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1.
CMAJ Open ; 11(6): E1083-E1092, 2023.
Article in English | MEDLINE | ID: mdl-37989514

ABSTRACT

BACKGROUND: Physicians play a critical role across health care delivery systems, yet their own well-being is often overlooked; mindfulness has been widely recommended as a promising modality to support physician wellness. We sought to explore how physicians experience and engage with a 5-week applied mindfulness program and how they perceive its impact on their personal well-being in the context of their daily lives. METHOD: We delivered the Applied Mindfulness Program for Medical Personnel (AMP-MP) at a tertiary care hospital in downtown Toronto, Canada. This prospective qualitative study consists of a thematic analysis of post-program interviews with physicians, from across different specialties, who participated in the AMP-MP. The program includes 2-hour sessions, delivered once a week over 5 weeks, and is based on the teachings of Thích Nhat Hanh. RESULTS: We interviewed 28 physicians after they completed the AMP-MP. Our data show that a 5-week training was sufficient for physicians to develop a foundational level of mindfulness that integrated into their daily life. Two themes were identified: mindfulness encourages behavioural and cognitive changes that facilitate well-being, and mindfulness improves communication with patients and colleagues. INTERPRETATION: Our results show applied mindfulness to be well received by physicians as an effective modality to increase their perceived sense of wellness and enhance communication with their patients and colleagues. Further research is necessary to better understand the individual and systemic implications of mindfulness training, and how this modality can complement other efforts being made to address and maintain physician wellness.

2.
Clin Oncol (R Coll Radiol) ; 30(9): 571-577, 2018 09.
Article in English | MEDLINE | ID: mdl-29773446

ABSTRACT

AIMS: Deep inspiration breath hold (DIBH) reduces cardiac radiation exposure by creating cardiac-chest wall separation in breast cancer radiotherapy. DIBH requires sustaining chest wall expansion for up to 40 s and involves complex co-ordination of thoraco-abdominal muscles, which may not be intuitive to patients. We investigated the effect of in-advance preparatory DIBH coaching and home practice on cardiac doses. MATERIALS AND METHODS: Successive patients from 1 February 2015 to 31 December 2016 with left-sided breast cancer who underwent tangential field radiotherapy utilising the DIBH technique were included. The study cohort consisted of patients treated by a physician who routinely provided DIBH coaching and home practice instructions at least 5 days before simulation. The control group included non-coached patients under another physician's care. Minimum, maximum and mean cardiac doses and V5, V10 and V30 from DIBH and free breathing simulation computed tomography scans were obtained from the planning system. DIBH and free breathing cardiac doses and volume exposures were compared between the coached and non-coached groups using the two-sample t-test, Fisher's exact test and the Mann-Whitney U-test. RESULTS: Twenty-seven coached and 42 non-coached patients were identified. The DIBH maximum cardiac dose was lower in coached patients at 13.1 Gy compared with 19.4 Gy without coaching (P = 0.004). The percentage cardiac volume exposure in DIBH was lower in coached patients; the DIBH V10 was 0.5% without coaching and 0.1% with coaching (P = 0.005). There was also a trend towards lower DIBH V5 in the coached group compared with the non-coached group (1.2% versus 1.9%, P = 0.071). No significant differences in patient cardiopulmonary comorbidity factors that might influence cardiac doses were found between the groups. CONCLUSIONS: Our results suggest that cardiac dose sparing can potentially be further improved with a 5 day regimen of preparatory DIBH coaching and in-advance home practice before simulation. These hypothesis-generating findings should be confirmed in a larger study.


Subject(s)
Breath Holding , Heart/radiation effects , Mentoring , Practice, Psychological , Radiation Exposure/prevention & control , Unilateral Breast Neoplasms/radiotherapy , Adult , Aged , Breathing Exercises , Female , Heart/diagnostic imaging , Humans , Middle Aged , Organs at Risk , Radiation Dosage , Tomography, X-Ray Computed
3.
J Ethnopharmacol ; 216: 8-17, 2018 Apr 24.
Article in English | MEDLINE | ID: mdl-29339110

ABSTRACT

BACKGROUND AND PURPOSE: Based on ethno-botanical information collected from diabetic patients in Cuba and firstly reported inhibition of PTP1B and DPPIV enzymes activities, Allophylus cominia (A. cominia) was identified as possible source of new drugs that could be used for the treatment of type 2 diabetes mellitus (T2-DM). EXPERIMENTAL APPROACH: in this study, the activity of the characterised extracts from A. cominia was tested on the glucose uptake using HepG2 and L6 cells, 3T3-L1 fibroblasts and adipocytes as well as their effect on the fat accumulation using 3T3-L1 adipocytes. KEY RESULTS: on 2-NBDG glucose uptake assay using HepG2 and L6 cells, extracts from A. cominia enhanced insulin activity by increasing glucose uptake. On HepG2 cells Insulin EC50 of 93 ± 21nM decreased to 13 ± 2nM in the presence of the flavonoids mixture from A.cominia. In L6 cells, insulin also produced a concentration-dependent increase with an EC50 of 28.6 ± 0.7nM; EC50 decreased to 0.08 ± 0.02nM and 5 ± 0.9nM in the presence of 100µg/ml of flavonoids and pheophytins mixtures, respectively. In 3T3-L1 fibroblasts, insulin had an EC50 of >1000nM that decreased to 38 ± 4nM in the presence of the flavonoids extract. However, in adipocytes, insulin produced a significant concentration-dependent increase and an EC50 of 30 ± 8nM was a further confirmation of the insulin responsiveness of the adipocytes to the insulin. At 100µg/ml, flavonoids and pheophytins extracts decreased fat accumulation in 3T3-L1 adipocytes by two folds in comparison to the control differentiated cells (p < 0.05). The crude extract of A. cominia did not show any enhancement of 2-NBDG uptake by 3T3-L1 adipocytes in the presence or absence of 100nM insulin. In addition, in fully differentiated adipocytes, both extracts produced significant decrease in lipid droplets in the cells and no lipid accumulation were seen after withdrawal of the extracts from the cell growth medium. However, there was no effect of both extracts on total protein concentration in cells as well as on Glut-4 transporters. CONCLUSIONS AND IMPLICATIONS: the pharmacological effects of the extracts from A. cominia observed in experimental diabetic models were shown in this study. A. cominia is potentially a new candidate for the treatment and management of T2-DM.


Subject(s)
4-Chloro-7-nitrobenzofurazan/analogs & derivatives , Adipocytes/drug effects , Adipogenesis/drug effects , Deoxyglucose/analogs & derivatives , Flavonoids/pharmacology , Hepatocytes/drug effects , Hypoglycemic Agents/pharmacology , Muscle, Skeletal/drug effects , Pheophytins/pharmacology , Plant Extracts/pharmacology , Sapindaceae , 3T3-L1 Cells , 4-Chloro-7-nitrobenzofurazan/metabolism , Adipocytes/metabolism , Animals , Deoxyglucose/metabolism , Dose-Response Relationship, Drug , Flavonoids/isolation & purification , Glucose Transporter Type 4/metabolism , Hep G2 Cells , Hepatocytes/metabolism , Humans , Hypoglycemic Agents/isolation & purification , Insulin/pharmacology , Lipid Droplets/drug effects , Lipid Droplets/metabolism , Mice , Muscle, Skeletal/metabolism , Pheophytins/isolation & purification , Phytotherapy , Plant Extracts/isolation & purification , Plants, Medicinal , Rats , Sapindaceae/chemistry , Time Factors
4.
J Ethnopharmacol ; 203: 39-46, 2017 May 05.
Article in English | MEDLINE | ID: mdl-28341245

ABSTRACT

BACKGROUND: Ethno-botanical information from diabetic patients in Cuba led to the identification of Allophylus cominia as a possible source of new drugs for the treatment of type 2 diabetes mellitus (T2-DM). EXPERIMENTAL: Chemical characterization of the extracts from A. cominia was carried out using chromatographic and spectroscopic methods. The extracts were tested for their activity on PTP1B, DPPIV, α-glucosidase enzymes and α-amylase. RESULTS: The flavonoid rich fractions from A. cominia inhibited DPPIV enzyme (75.3±2.33%) at 30µg/ml and produced a concentration-dependent inhibition against DPPIV with a Ki value of 2.6µg/ml. At 30µg/ml, flavonoids and pheophytins extracts significantly inhibited PTP1B enzyme (100±2.6% and 68±1% respectively). The flavonoids, pheophytin A and pheophytin B fractions showed significant concentration-dependent inhibition against PTP1B with Ki values of 3µg/ml, 0.64µg/ml and 0.88µg/ml respectively. At 30µg/ml, the flavonoid fraction significantly inhibited α-glucosidase enzyme (86±0.3%) in a concentration-dependent pattern with a Ki value of 2µg/ml. None of the fractions showed significant effects on α-amylase. Fatty acids, tannins, pheophytins A and B, and a mixture of flavonoids were detected in the methanolic extract from A. cominia. The identified flavonoids were mearnsitrin, quercitrin, quercetin-3-alloside, and naringenin-7-glucoside. CONCLUSION: The pharmacological effects of the extracts from A. cominia earlier observed in experimental diabetic models was confirmed in this study. Thus a new drug or formulation for the treatment of T2-DM could be developed from A. cominia.


Subject(s)
Flavonoids/pharmacology , Pheophytins/pharmacology , Plant Extracts/pharmacology , Sapindaceae/chemistry , Animals , Diabetes Mellitus, Type 2/chemically induced , Diabetes Mellitus, Type 2/drug therapy , Dipeptidyl Peptidase 4/drug effects , Dipeptidyl Peptidase 4/metabolism , Dose-Response Relationship, Drug , Flavonoids/administration & dosage , Flavonoids/isolation & purification , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/isolation & purification , Hypoglycemic Agents/pharmacology , Pheophytins/administration & dosage , Pheophytins/isolation & purification , Plant Extracts/administration & dosage , Plant Extracts/chemistry , Protein Tyrosine Phosphatase, Non-Receptor Type 1/antagonists & inhibitors , Protein Tyrosine Phosphatase, Non-Receptor Type 1/metabolism , Swine , alpha-Amylases/antagonists & inhibitors , alpha-Amylases/metabolism , alpha-Glucosidases/drug effects , alpha-Glucosidases/metabolism
5.
PLoS One ; 10(3): e0120634, 2015.
Article in English | MEDLINE | ID: mdl-25793734

ABSTRACT

MAIN OBJECTIVE: The thinning of prelaminar tissue and prelamina cupping is known to occur by ischemia, as we see in anterior ischemic optic neuropathy. Since normal tension glaucoma (NTG) is thought to be more related to vascular factor than in primary open-angle glaucoma (POAG), we hypothesized that prelamina thinning may occur prominently in NTG patients. This study investigated the difference in prelaminar tissue thickness between patients with POAG and NTG and verified the factors related to prelaminar thinning. METHODS: Complete ophthalmic examination including standard automatic perimetry was performed in all patients. The prelaminar tissue thickness was measured in all patients by performing enhanced depth imaging with a Heidelberg Spectralis Optical Coherence Tomography. The retinal nerve fiber layer and optic nerve head parameters were obtained using the Heidelberg Retina Tomography II and Cirrus Optical Coherence Tomography. Various ocular factors and their relationships with prelaminar thickness were analyzed. RESULTS: The mean prelaminar tissue thickness was significantly thinner in patients with POAG than in those with NTG. The difference in the prelaminar thickness between patients with POAG and those with NTG was greater in the early field defect group than in the moderate and severe field groups. In multivariate analysis, the mean prelaminar thickness was related to the intraocular pressure, mean deviation, cup-disc ratio, and cup volume. CONCLUSIONS: The prelaminar tissue was thinner in patients with POAG than in patients with NTG, and intraocular pressure had a strong influence on the prelaminar thickness in both POAG and NTG. This may indicate that mechanical compression is the main pathogenic factor in both POAG and NTG.


Subject(s)
Glaucoma, Open-Angle/pathology , Low Tension Glaucoma/pathology , Retina/pathology , Female , Humans , Male , Middle Aged , Tomography, Optical Coherence
6.
Neurochem Int ; 79: 12-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25445986

ABSTRACT

Oxidative stress and calcium imbalance are consistently reported in bipolar disorder (BD). Polymorphism of voltage-dependent calcium channel, L type, alpha 1C subunit (CACNA1c), which is responsible for the regulation of calcium influx, was also shown to have a strong association with BD. These alterations can lead to a number of different consequences in the cell including production of reactive species causing oxidative damage to proteins, lipids and DNA. Lithium is the most frequent medication used for the treatment of BD. Despite lithium's effects, long-term use can result in many negative side effects. Therefore, there is an urgent need for the development of drugs that may have similar biological effects as lithium without the negative consequences. Moreover, polyphenols are secondary metabolites of plants that present multi-faceted molecular abilities, such as regulation of cellular responses. Vitis labrusca extract (VLE), a complex mixture of polyphenols obtained from seeds of winery wastes of V. labrusca, was previously characterized by our group. This extract presented powerful antioxidant and neuroprotective properties. Therefore, the ability of VLE to ameliorate the consequences of hydrogen peroxide (H2O2)-induced redox alterations to cell viability, intracellular calcium levels and the relative levels of the calcium channel CACNA1c in comparison to lithium's effects were evaluated using a neuroblastoma cell model. H2O2 treatment increased cell mortality through apoptotic and necrotic pathways leading to an increase in intracellular calcium levels and alterations to relative CACNA1c levels. VLE and lithium were found to similarly ameliorate cell mortality through regulation of the apoptotic/necrotic pathways, decreasing intracellular calcium levels and preventing alterations to the relative levels of CACNA1c. The findings of this study suggest that VLE exhibits protective properties against oxidative stress-induced alterations similar to that of lithium. These findings suggest that VLE may be an attractive potential candidate as a novel therapeutic agent for BD.


Subject(s)
Lithium/pharmacology , Neurons/drug effects , Plant Extracts/pharmacology , Vitis/chemistry , Apoptosis/drug effects , Bipolar Disorder/drug therapy , Calcium Channels, L-Type/drug effects , Calcium Channels, L-Type/metabolism , Calcium Signaling/drug effects , Cell Death/drug effects , Cell Line , Humans , Necrosis , Oxidation-Reduction
7.
Intern Med J ; 44(6): 525-36, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24946813

ABSTRACT

New oral anticoagulants (NOAC) are becoming available as alternatives to warfarin to prevent systemic embolism in patients with non-valvular atrial fibrillation and for the treatment and prevention of venous thromboembolism. An in-depth understanding of their pharmacology is invaluable for appropriate prescription and optimal management of patients receiving these drugs should unexpected complications (such as bleeding) occur, or the patient requires urgent surgery. The Australasian Society of Thrombosis and Haemostasis has set out to inform physicians on the use of the different NOAC based on current available evidence focusing on: (i) selection of the most suitable patient groups to receive NOAC, (ii) laboratory measurements of NOAC in appropriate circumstances and (iii) management of patients taking NOAC in the perioperative period, and strategies to manage bleeding complications or 'reverse' the anticoagulant effects for urgent invasive procedures.


Subject(s)
Anticoagulants/therapeutic use , Benzimidazoles/therapeutic use , Morpholines/therapeutic use , Pyrazoles/therapeutic use , Pyridones/therapeutic use , Thiophenes/therapeutic use , Thrombophilia/drug therapy , beta-Alanine/analogs & derivatives , Administration, Oral , Anticoagulants/administration & dosage , Anticoagulants/adverse effects , Anticoagulants/pharmacokinetics , Atrial Fibrillation/complications , Benzimidazoles/administration & dosage , Benzimidazoles/adverse effects , Benzimidazoles/pharmacokinetics , Blood Coagulation Tests , Blood Loss, Surgical/prevention & control , Contraindications , Dabigatran , Drug Interactions , Drug Monitoring , Drug Substitution , Elective Surgical Procedures , Emergencies , Hematoma, Epidural, Spinal/chemically induced , Hematoma, Epidural, Spinal/prevention & control , Hemorrhage/chemically induced , Hemorrhage/prevention & control , Hemorrhage/therapy , Humans , Kidney Diseases/metabolism , Liver Diseases/metabolism , Morpholines/administration & dosage , Morpholines/adverse effects , Morpholines/pharmacokinetics , Patient Selection , Pyrazoles/administration & dosage , Pyrazoles/adverse effects , Pyridones/administration & dosage , Pyridones/adverse effects , Rivaroxaban , Stroke/complications , Thiophenes/administration & dosage , Thiophenes/adverse effects , Thiophenes/pharmacokinetics , Thrombophilia/etiology , beta-Alanine/administration & dosage , beta-Alanine/adverse effects , beta-Alanine/pharmacokinetics , beta-Alanine/therapeutic use
8.
J Consult Clin Psychol ; 80(3): 365-72, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22409641

ABSTRACT

OBJECTIVE: To examine whether metacognitive psychological skills, acquired in mindfulness-based cognitive therapy (MBCT), are also present in patients receiving medication treatments for prevention of depressive relapse and whether these skills mediate MBCT's effectiveness. METHOD: This study, embedded within a randomized efficacy trial of MBCT, was the first to examine changes in mindfulness and decentering during 6-8 months of antidepressant treatment and then during an 18-month maintenance phase in which patients discontinued medication and received MBCT, continued on antidepressants, or were switched to a placebo. In total, 84 patients (mean age = 44 years, 58% female) were randomized to 1 of these 3 prevention conditions. In addition to symptom variables, changes in mindfulness, rumination, and decentering were assessed during the phases of the study. RESULTS: Pharmacological treatment of acute depression was associated with reductions in scores for rumination and increased wider experiences. During the maintenance phase, only patients receiving MBCT showed significant increases in the ability to monitor and observe thoughts and feelings as measured by the Wider Experiences (p < .01) and Decentering (p < .01) subscales of the Experiences Questionnaire and by the Toronto Mindfulness Scale. In addition, changes in Wider Experiences (p < .05) and Curiosity (p < .01) predicted lower Hamilton Rating Scale for Depression scores at 6-month follow-up. CONCLUSIONS: An increased capacity for decentering and curiosity may be fostered during MBCT and may underlie its effectiveness. With practice, patients can learn to counter habitual avoidance tendencies and to regulate dysphoric affect in ways that support recovery.


Subject(s)
Antidepressive Agents/therapeutic use , Cognitive Behavioral Therapy , Depressive Disorder/therapy , Adult , Depressive Disorder/drug therapy , Depressive Disorder/prevention & control , Depressive Disorder/psychology , Female , Humans , Male , Middle Aged , Secondary Prevention , Treatment Outcome
9.
Arch Dis Child Fetal Neonatal Ed ; 97(4): F295-8, 2012 Jul.
Article in English | MEDLINE | ID: mdl-21406452

ABSTRACT

Preterm infants, especially very preterm infants, are usually growth-restricted at the time of hospital discharge. Proposed interventions to promote catch-up growth following hospital discharge include multinutrient fortification of expressed breast milk for breastfed infants and nutrient-enriched formula milk for formula-fed infants. The current evidence to support these strategies is limited. Fortification of expressed breast milk may increase weight gain and skeletal and head growth during infancy, but more research is needed to define which nutrients confer most benefit, and which population of infants is likely to receive most benefit. Trials that have assessed feeding preterm infants with commercially available nutrient-enriched formula milk ('preterm' or 'postdischarge' formulae) compared with standard formula milk have not found consistent evidence of an effect on growth parameters or development, probably because ad libitum fed infants reduce their intake relative to the calorie-density of the milk. Future studies should focus on the effect of formulae enriched with protein and minerals rather than energy and assess the effect on lean mass and skeletal growth.


Subject(s)
Growth Disorders/diet therapy , Infant, Premature, Diseases/diet therapy , Food, Fortified , Growth Disorders/physiopathology , Humans , Infant Formula , Infant Nutritional Physiological Phenomena , Infant, Newborn , Infant, Premature , Infant, Premature, Diseases/physiopathology , Milk, Human , Patient Discharge
10.
West Indian Med J ; 59(3): 245-8, 2010 Jun.
Article in English | MEDLINE | ID: mdl-21291100

ABSTRACT

Anxiety modulation often requires pharmaceutical intervention, and though effective in the short-term, benzodiazepines may cause impaired motor function. As a potential alternative, anxiety-modulating effects of a neem leaf (Azadirachta indica, A Juss) extract were investigated using ethological analysis of rat behaviour on an elevated X maze and compared with diazepam treatment. Sexually immature female Sprague-Dawley rats received 0.07 or 7 mg/kg neem leaf steroidal extract, a sham injection, a 1% DMSO/saline vehicle, 2 mg/kg diazepam or no treatment one hour prior to a recorded five-minute exploration of the elevated X maze. Neem matched diazepam in anxiety reduction as both treatments caused a decrease in per cent protected stretched-attend postures (PPSAP). Neem treatment had no effect on closed arm entries or total rears, distinguishing it pharmacologically from diazepam which resulted in a predictable decrease in those locomotor measures. Whereas both neem and diazepam reduced anxiety in complex ethological behavioural indices, only neem produced anxiolysis without motor deficiency.


Subject(s)
Anxiety/drug therapy , Azadirachta , Phytotherapy , Plant Extracts/therapeutic use , Plant Leaves , Animals , Anti-Anxiety Agents/pharmacology , Diazepam/pharmacology , Female , Rats , Rats, Sprague-Dawley
11.
J Clin Psychopharmacol ; 27(5): 493-7, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17873683

ABSTRACT

OBJECTIVE: Neuroanatomic evidence suggests that patients with bipolar disorder (BD) have impaired cortical inhibition (CI). However, there is little in vivo neurophysiological evidence supporting the occurrence of such impairments in this disorder. Using 3 transcranial magnetic stimulation paradigms, known as short-interval CI (SICI), cortical silent period (SP), and interhemispheric inhibition (IHI), the authors measured inhibition in the motor cortex. METHOD: Fifteen patients with BD and 15 healthy subjects were enrolled. Short-interval CI involves stimulating with a subthreshold pulse a few milliseconds before a suprathreshold pulse, thereby inhibiting the size of the motor-evoked potential (MEP) produced by the suprathreshold pulse. In the SP paradigm, inhibition is reflected by the SP duration (ie, the duration of electromyographic activity cessation following a transcranial magnetic stimulation-induced MEP). Interhemispheric inhibition involves a subthreshold conditioning stimulus applied to the right motor cortex several milliseconds before a suprathreshold test stimulus is applied to the left motor cortex which inhibits the size of the MEP produced by the test stimulus by 50% to 75%. RESULTS: Patients with BD demonstrated deficits in all 3 paradigms: SICI (F1,28 = 5.55, P = 0.03; Cohen d = 0.86), SP (F1,28 = 5.24, P = 0.03; Cohen d = 0.84), and IHI (F1,28 = 3.41, P = 0.02; Cohen d = 0.77) compared with healthy volunteers with a large effect size. CONCLUSIONS: Our study supports the hypothesis that CI is decreased in BD. Further understanding of the neurophysiology of such deficiencies may help to elucidate future treatment options.


Subject(s)
Bipolar Disorder/physiopathology , Motor Cortex/physiopathology , Neural Inhibition/physiology , Transcranial Magnetic Stimulation/methods , Adult , Electromyography , Evoked Potentials, Motor , Female , Functional Laterality , Humans , Male , Middle Aged , Severity of Illness Index , Synaptic Transmission/physiology , gamma-Aminobutyric Acid/metabolism
12.
J Biomed Opt ; 11(4): 041125, 2006.
Article in English | MEDLINE | ID: mdl-16965153

ABSTRACT

The phenomenon of enhanced backscattering (EBS) of light, also known as coherent backscattering (CBS) of light, has been the object of intensive investigation in nonbiological media over the last two decades. However, there have been only a few attempts to explore EBS for tissue characterization and diagnosis. We have recently made progress in the EBS measurements in tissue by taking advantage of low spatial coherence illumination, which has led us to the development of low-coherence enhanced backscattering (LEBS) spectroscopy. In this work, we review the current state of research on LEBS. After a brief discussion of the basic principle of EBS and LEBS, we present an overview of the unique features of LEBS for tissue characterization, and show that LEBS enables depth-selective spectroscopic assessment of mucosal tissue. Then, we demonstrate the potential of LEBS spectroscopy for predicting the risk of colon carcinogenesis and colonoscopy-free screening for colorectal cancer (CRC).


Subject(s)
Colonic Neoplasms/diagnosis , Refractometry/methods , Spectrum Analysis/methods , Tomography, Optical Coherence/methods , Animals , Drug Evaluation, Preclinical/methods , Humans , Light , Reproducibility of Results , Scattering, Radiation , Sensitivity and Specificity
13.
Life Sci ; 79(21): 2001-9, 2006 Oct 19.
Article in English | MEDLINE | ID: mdl-16854434

ABSTRACT

Recent work has indicated that prolonged treatment with nitric oxide (NO) donors results in tissue storage of NO as S-nitrosothiols and N-nitrosamines. The possibility thus exists that NO treatment may result in the development of tissue stores of NO with functionally significant effects following removal of the original NO source. In these studies, the effects of 10 min treatment with two chemically distinct NO sources, S-nitrosoglutathione (GSNO) and (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA-NO) were determined in canine pulmonary artery using a superfusion system that permitted continuous isometric force recording during addition and removal of the NO donors. Relaxation that persisted for up to 1 h after removal of the NO source, was demonstrated for both NO sources, but at lower concentrations relative to the relaxant EC(50) for GSNO versus DEA-NO. Persistent relaxation with both NO sources was fully reversed by both the sGC inhibitor, ODQ, and an inhibitor of cGMP-dependent protein kinase, Rp-8-Br-PET-cGMPS, indicating that persistent relaxation was consistent with persistent activation of the sGC-cGMP signaling pathway. In separate measurements, a GSNO-induced persistent increase in both tissue cGMP ([cGMP](i)) and relaxation were fully reversed by both ODQ and the thiol reducing agent dithiothreitol (DTT). The results indicate that vascular smooth muscle is capable of converting short-lived NO responses following short term exposure to NO donors by a mechanism consistent with prolonged sGC activation, resulting in persistent relaxation. Reversal of this cGMP-dependent process with DTT suggests that it occurs via mechanisms that are thiol redox sensitive.


Subject(s)
Guanylate Cyclase/metabolism , Nitric Oxide Donors/pharmacology , Nitric Oxide/metabolism , Pulmonary Artery/drug effects , Vasodilation/drug effects , Animals , Cyclic GMP/metabolism , Dogs , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Female , In Vitro Techniques , Isometric Contraction/drug effects , Male , Nitric Oxide Donors/chemistry , Pulmonary Artery/enzymology , Structure-Activity Relationship , Time Factors
14.
West Indian Med J ; 55(1): 4-8, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16755811

ABSTRACT

Choline is important for the synthesis of acetylcholine, an integral neurotransmitter involved in memory formation. In order to investigate the effect of choline supplementation on memory consolidation, the study utilized a T-maze to facilitate passive avoidance learning and memory in young female Sprague-Dawley rats. Rats were placed in two groups; choline-supplemented that received choline chloride daily for two weeks, and control that received vehicle daily for two weeks. Rats were evaluated to determine their ability to avoid an aversive electric foot-shock (0.1 mA at 60V) when they characteristically entered the preferred dark area (DA) of the T-maze. Both groups of rats showed preference, without significant difference, for entry into DA of the T-maze. However, fifteen minutes after passive avoidance both choline supplemented and control rats avoided entry into DA. This display of DA avoidance 15 minutes after training, suggests that both groups of rats had acquired short-term memory of the aversive stimulus. However, when the test was repeated 24 hours after training, the control group did not avoid entry into DA, whereas the choline-supplemented group either avoided entry or entered after a significantly longer latency period (p < 0.01). These results suggest that supplementation with choline facilitated the consolidation of short-term memory of the avoidance learning into intermediate long-term memory in young rats.


Subject(s)
Avoidance Learning/drug effects , Choline/pharmacology , Dietary Supplements , Memory, Short-Term/drug effects , Age Factors , Animals , Female , Memory/drug effects , Rats , Rats, Sprague-Dawley , Time Factors
15.
J Psychiatry Neurosci ; 31(3): 189-96, 2006 May.
Article in English | MEDLINE | ID: mdl-16699605

ABSTRACT

OBJECTIVE: Many studies indicate a genetic predisposition to bipolar disorder (BD) and suggest that a number of abnormal genes are involved in its development. In this study, we used DNA microarray technology to analyze gene-expression profiles in the postmortem frontal cortex of subjects with BD. METHODS: Microarray hybridization was performed using human 19K microarray with universal human reference RNA in each hybridization. The reference cDNA was labelled with Cy3 and experimental cDNA, with Cy5. Glass array slides were cohybridized with equal amounts of mixed reference and experimental cDNA. Selected gene targets were further verified using real-time polymerase chain reaction (PCR). RESULTS: We found that 831 genes were differentially expressed in subjects with BD, including a number of genes in the mitochondrial electron transport chain (ETC), phosphatidylinositol-signalling system and glycolysis/ gluconeogenesis. Eight genes coding for the components of the mitochondrial ETC were identified along with 15 others related to mitochondrial function. Downregulation of NADH-ubiquinone oxidoreductase 20-kd subunit (ETC complex I), cytochrome c oxidase polypeptide Vic (ETC complex IV) and ATP synthase lipid-binding protein (ETC complex V) were further verified by real-time PCR. We also found that the expression of the NADH-ubiquinone oxidoreductase 20-kd subunit was increased in subjects with BD who were receiving mood-stabilizing treatment with lithium at the time of death, when compared with subjects with BD who were not being treated with lithium. CONCLUSIONS: Because the mitochondrial ETC is a major source for the generation of reactive oxygen species, these findings suggest that oxidative damage may play an important role in the pathophysiology of BD and that neuroprotection against this damage may be involved in the effect of lithium treatment.


Subject(s)
Bipolar Disorder/genetics , Bipolar Disorder/metabolism , Electron Transport Chain Complex Proteins/genetics , Electron Transport Chain Complex Proteins/metabolism , Electron Transport/physiology , Prefrontal Cortex/metabolism , Adult , DNA, Complementary/biosynthesis , DNA, Complementary/genetics , Down-Regulation , Female , Humans , Male , Middle Aged , Oligonucleotide Array Sequence Analysis , Reverse Transcriptase Polymerase Chain Reaction
16.
Am J Psychiatry ; 163(2): 257-64, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16449479

ABSTRACT

OBJECTIVE: The authors previously identified depression-specific differences in brain responses to an emotional challenge in patients with bipolar and unipolar mood disorder. In this study, potential markers of bipolar risk and resilience were examined in a new cohort of lithium-responsive bipolar patients and their healthy siblings. METHOD: Changes in regional cerebral blood flow (rCBF) were measured with [(15)O]water positron emission tomography after induction of transient sadness in nine euthymic lithium responders and nine healthy siblings. The patterns of change in these groups were compared, and then they were contrasted with previous findings on bipolar responders to valproate. RESULTS: Common to all three groups with induced sadness were rCBF increases in the dorsal/rostral anterior cingulate and anterior insula and decreases in the orbitofrontal and inferior temporal cortices. Distinguishing the groups were decreases in the medial frontal cortex in the patients but an increase in this region in the siblings. DISCUSSION: Common changes with emotional challenge were identified in bipolar patients and their healthy siblings. These were not seen previously in healthy subjects without a family history of mood disorder, suggesting a potential marker of bipolar risk. The siblings' unique increases in the medial frontal cortex appear to identify a compensatory response in this at-risk group, as this pattern was not seen previously in healthy subjects without depression risk factors. This differential change pattern in patients and their siblings highlights the role of the anterior cingulate and medial frontal regions in mediating resiliency and vulnerability in bipolar disorder families.


Subject(s)
Biomarkers , Bipolar Disorder/diagnosis , Brain/blood supply , Brain/diagnostic imaging , Emotions/physiology , Positron-Emission Tomography , Siblings/psychology , Adult , Bipolar Disorder/diagnostic imaging , Bipolar Disorder/drug therapy , Brain/drug effects , Cohort Studies , Depressive Disorder/diagnosis , Depressive Disorder/diagnostic imaging , Depressive Disorder/drug therapy , Emotions/drug effects , Female , Frontal Lobe/blood supply , Frontal Lobe/diagnostic imaging , Gyrus Cinguli/blood supply , Gyrus Cinguli/diagnostic imaging , Humans , Lithium/pharmacology , Lithium/therapeutic use , Male , Oxygen Radioisotopes , Regional Blood Flow/drug effects , Regional Blood Flow/physiology , Risk Factors , Temporal Lobe/blood supply , Temporal Lobe/diagnostic imaging , Valproic Acid/pharmacology , Valproic Acid/therapeutic use , Water
17.
West Indian med. j ; West Indian med. j;55(1): 4-8, Jan. 2006. tab, graf
Article in English | LILACS | ID: lil-472679

ABSTRACT

Choline is important for the synthesis of acetylcholine, an integral neurotransmitter involved in memory formation. In order to investigate the effect of choline supplementation on memory consolidation, the study utilized a T-maze to facilitate passive avoidance learning and memory in young female Sprague-Dawley rats. Rats were placed in two groups; choline-supplemented that received choline chloride daily for two weeks, and control that received vehicle daily for two weeks. Rats were evaluated to determine their ability to avoid an aversive electric foot-shock (0.1 mA at 60V) when they characteristically entered the preferred dark area (DA) of the T-maze. Both groups of rats showed preference, without significant difference, for entry into DA of the T-maze. However, fifteen minutes after passive avoidance both choline supplemented and control rats avoided entry into DA. This display of DA avoidance 15 minutes after training, suggests that both groups of rats had acquired short-term memory of the aversive stimulus. However, when the test was repeated 24 hours after training, the control group did not avoid entry into DA, whereas the choline-supplemented group either avoided entry or entered after a significantly longer latency period (p < 0.01). These results suggest that supplementation with choline facilitated the consolidation of short-term memory of the avoidance learning into intermediate long-term memory in young rats.


La colina es importante para la síntesis de la acetilcolina – un neurotransmisor integral que participa en la formación de la memoria. Para investigar el efecto de la suplementación con colina en la consolidación de la memoria, el estudio utilizó un laberinto T para facilitar la memoria y el aprendizaje de evitación pasiva en ratas hembras jóvenes Sprague-Dawley. Las ratas fueron colocadas en dos grupos: uno que recibió cloruro de colina diariamente por espacio de dos semanas, y uno de control que recibió vehículo diariamente por dos semanas. Las ratas fueron evaluadas a fin de determinar su habilidad para evitar un choque eléctrico aversivo (0.1mA a 60V) cuando entraban característicamente a la preferida área oscura (AO) del laberinto en T. Ambos grupos de ratas mostraron preferencia – sin diferencia significativa – por entrar en el área oscura del laberinto en T. Sin embargo, quince minutos después de la evitación pasiva, tanto las ratas que recibieron la suplementación con colina como las ratas de control, evitaban entrar al área oscura. El hecho de que se observe la evitación del área oscura15 minutos después del entrenamiento, sugiere que ambos grupos de ratas habían adquirido una memoria a corto plazo del estímulo aversivo. Sin embargo, cuando la prueba se repitió 24 horas después del entrenamiento, el grupo de control no evitó el entrar al AO, mientras que el grupo que recibió el complemento de colina, o evitó entrar o entró luego de un período de latencia significativamente más largo (P < 0.01). Por lo tanto, estos resultados sugieren por consiguiente que la suplementación con colina facilitó la consolidación de la memoria a corto plazo del aprendizaje de la evitación, y su transformación en memoria a largo plazo en las ratas jóvenes.


Subject(s)
Animals , Female , Rats , Avoidance Learning/drug effects , Choline/pharmacology , Memory, Short-Term/drug effects , Dietary Supplements , Age Factors , Time Factors , Memory/drug effects , Rats, Sprague-Dawley
18.
Int J Impot Res ; 15(5): 347-54, 2003 Oct.
Article in English | MEDLINE | ID: mdl-14562136

ABSTRACT

Phosphodiesterase (PDE) inhibitors represent an important advance in the treatment of erectile dysfunction (ED). In spite of widespread use and generally good efficacy, as a class they remain ineffective in 15-57% of men. Specific cohorts of patients with severe vascular or neurogenic basis to their ED, such as diabetic men or those who have undergone radical pelvic surgery, demonstrate lower response rates with PDE inhibition treatment. We believe that circulating levels of nitric oxide (NO) may be enhanced through delivery of adequate concentrations of free oxygen radical scavenger molecules such as vitamin E. Higher levels of NO, theoretically, should produce increased penile blood flow with the potential for a synergistic effect when combined with a PDE5 inhibitor. With this hypothesis in mind, 20 adult male Sprague-Dawley streptozotocin-induced (60 mg/kg i.p.) diabetic rats were divided into four therapeutic groups (n=5). Group I--control animals received peanut oil, group II--vitamin E 20 IU/day, group III--sildenafil 5 mg/kg/day and group IV--vitamin E 20 IU/day plus sildenafil 5 mg/kg/day, by oral gavage daily for 3 weeks. Erectile function was assessed as a rise in intracavernous pressure following cavernous nerve electrostimulation. Penile tissue was harvested to determine the changes in tissue morphology including neuronal nitric oxide synthase, smooth muscle alpha-actin and endothelial cell integrity. PDE5 protein content and activity were measured. Significant increases in intracavernous pressure were measured in the animals receiving combined vitamin E plus sildenafil treatment. Immunohistochemical staining showed increases of neuronal nitric oxide synthase, endothelial cell and smooth muscle cell staining. Western blot analysis did not show significant differences of PDE5 protein between the groups. However, higher PDE5 activity was measured in the sildenafil group and lower activity of PDE5 was recorded in the cohort receiving vitamin E with sildenafil. Vitamin E enhanced the therapeutic effect of the PDE5 inhibitor in a meaningful way in this animal model of diabetes. This study indicates a potential means of salvaging erectile function among patients who are refractory to sildenafil.


Subject(s)
3',5'-Cyclic-GMP Phosphodiesterases/antagonists & inhibitors , Erectile Dysfunction/drug therapy , Free Radical Scavengers/pharmacology , Phosphodiesterase Inhibitors/pharmacology , Piperazines/pharmacology , Vitamin E/pharmacology , Animals , Cyclic Nucleotide Phosphodiesterases, Type 5 , Diabetes Complications , Disease Models, Animal , Drug Therapy, Combination , Erectile Dysfunction/complications , Male , Purines , Rats , Rats, Sprague-Dawley , Sildenafil Citrate , Sulfones
19.
Environ Microbiol ; 3(9): 600-3, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11683870

ABSTRACT

An enriched sulphidogenic consortium capable of mineralizing benzene was used to study the metabolic pathway of anaerobic benzene degradation. Benzoate was detected in active cultures and benzene was confirmed to be the source of this benzoate by the addition of deuterated benzene (D6) and subsequent detection of deuterated benzoate (D5) in active cultures but not in autoclaved controls. Benzoate was utilized by this culture at 1/12 the rate of benzene, while its presence did not inhibit benzene utilization. The benzene utilization rate was reduced, however, in the presence of 2-fluorobenzoate. When the culture was supplemented with [(13)C]-bicarbonate, the carboxyl group on benzoate was not labelled with [(13)C]-carbon, suggesting that this transformation relies on a more complex set of reactions than simple addition of carbonate.


Subject(s)
Bacteria/metabolism , Benzene/metabolism , Benzoates/metabolism , Bacteria/growth & development , Biodegradation, Environmental , Culture Media , Gas Chromatography-Mass Spectrometry , Methane/metabolism , Substrate Specificity , Sulfates/metabolism
20.
Antimicrob Agents Chemother ; 45(8): 2210-4, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11451676

ABSTRACT

The activity of telithromycin, a new ketolide, was evaluated in vitro and in vivo against Mycobacterium avium complex (MAC) strains. The MIC of telithromycin for several M. avium isolates obtained from the blood of AIDS patients ranged from 16 to >128 microg/ml (MIC at which 90% of isolates are inhibited, >128 microg/ml), and the compound did show activity in the macrophage system at concentrations greater than 8 or 16 microg/ml, but this was dependent on the MAC strain used. Telithromycin was then administered to mice infected with MAC strain 101 for 4 weeks at doses of 100, 200, or 400 mg/kg of body weight/day. Treatment with 100 and 200 mg/kg/day was bacteriostatic, but at 400 mg/kg/day telithromycin was bactericidal for MAC strains. The frequency of the emergence of resistance to telithromycin was low despite prolonged usage (12 weeks). This study demonstrates that telithromycin is active in vivo against MAC and warrants further evaluation.


Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance , Ketolides , Macrolides , Macrophages/microbiology , Mycobacterium avium Complex/drug effects , Mycobacterium avium-intracellulare Infection/drug therapy , Animals , Dose-Response Relationship, Drug , Female , Humans , Mice , Mice, Inbred C57BL , Microbial Sensitivity Tests , Mycobacterium avium Complex/isolation & purification , Mycobacterium avium-intracellulare Infection/blood
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