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1.
AJNR Am J Neuroradiol ; 44(2): 157-164, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36702499

RESUMO

BACKGROUND AND PURPOSE: Given the increased use of stereotactic radiosurgical thalamotomy and other ablative therapies for tremor, new biomarkers are needed to improve outcomes. Using resting-state fMRI and MR tractography, we hypothesized that a "connectome fingerprint" can predict tremor outcomes and potentially serve as a targeting biomarker for stereotactic radiosurgical thalamotomy. MATERIALS AND METHODS: We evaluated 27 patients who underwent unilateral stereotactic radiosurgical thalamotomy for essential tremor or tremor-predominant Parkinson disease. Percentage postoperative improvement in the contralateral limb Fahn-Tolosa-Marin Clinical Tremor Rating Scale (TRS) was the primary end point. Connectome-style resting-state fMRI and MR tractography were performed before stereotactic radiosurgery. Using the final lesion volume as a seed, "connectivity fingerprints" representing ideal connectivity maps were generated as whole-brain R-maps using a voxelwise nonparametric Spearman correlation. A leave-one-out cross-validation was performed using the generated R-maps. RESULTS: The mean improvement in the contralateral tremor score was 55.1% (SD, 38.9%) at a mean follow-up of 10.0 (SD, 5.0) months. Structural connectivity correlated with contralateral TRS improvement (r = 0.52; P = .006) and explained 27.0% of the variance in outcome. Functional connectivity correlated with contralateral TRS improvement (r = 0.50; P = .008) and explained 25.0% of the variance in outcome. Nodes most correlated with tremor improvement corresponded to areas of known network dysfunction in tremor, including the cerebello-thalamo-cortical pathway and the primary and extrastriate visual cortices. CONCLUSIONS: Stereotactic radiosurgical targets with a distinct connectivity profile predict improvement in tremor after treatment. Such connectomic fingerprints show promise for developing patient-specific biomarkers to guide therapy with stereotactic radiosurgical thalamotomy.


Assuntos
Conectoma , Tremor Essencial , Radiocirurgia , Humanos , Tremor/diagnóstico por imagem , Tremor/cirurgia , Resultado do Tratamento , Tálamo/diagnóstico por imagem , Tálamo/cirurgia , Imageamento por Ressonância Magnética , Tremor Essencial/cirurgia
2.
Front Pediatr ; 9: 707650, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34722416

RESUMO

Background: It has been suggested that children and infants can develop multisystem inflammatory syndrome in children (MIS-C) in response to a SARS-CoV-2 infection and that Black children are overrepresented among cases. The aim of the current study was to quantify the association between Black, Asian, or other non-White genetic background and COVID-19-related MIS-C in children and infants. Methods: Eight different research groups contributed cases of MIS-C, potentially related to SARS-CoV-2 infection. Several sensitivity analyses were performed, including additional data available from the literature. Analyses were stratified by geographical region. Results: Seventy-three cases from nine distinct geographical regions were included in the primary analyses. In comparison to White children, the relative risk for developing MIS-C after SARS-CoV-2 infection was 15 [95% confidence interval (CI): 7.1 to 32] for Black children, 11 (CI: 2.2 to 57) for Asian, and 1.6 (CI: 0.58 to 4.2) for other ethnic background. Conclusion: Pediatricians should be aware of the fact that the risk of COVID-19-related MIS-C is severely increased in Black children.

3.
Animal ; 15(3): 100136, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33785184

RESUMO

Intramuscular fat (IMF) content affects eating and nutritional quality of lamb meat. Muscle density measured by computer tomography is an in vivo proxy measure of IMF content that affects eating and nutritional quality of lamb meat. Lambs sired by high muscle density (HMD) or low muscle density (LMD) rams, selected for slaughter on commercial criteria were measured for meat quality and nutritional traits. A restricted maximum likelihood model was used to compare lamb traits. Additionally, regression analysis of sire estimated breeding value (EBV) for muscle density was performed for each meat quality trait. Muscle density EBV had a negative regression with IMF content (P < 0.001). For each unit increase in muscle density EBV, there was a significant decrease in loin (-1.69 mg/100 g fresh weight) and topside IMF (-0.03 mg/100 g fresh weight). Muscle density EBV had a negative regression with grouped saturated and monounsaturated fatty acids concentration (and monounsaturated proportion P < 0.001). Muscle density EBV had a negative regression with loin sensory traits tenderness, juiciness and overall liking and many novel tenderness sensory traits measured (P < 0.05). Selecting for LMD EBV increased IMF content and favourable meat eating quality traits. In contrast, sire muscle density EBV had a positive regression with loin polyunsaturated:saturated fat ratio and grouped polyunsaturated proportion traits (including total polyunsaturated proportion, total omega-6 (n-6) and total omega-3 (n-3) fatty acids (P < 0.001). This is explained by the fact that as sire muscle density EBV increases, polyunsaturated fatty acid proportion increases and the proportion of saturated and monounsaturated fatty acid content decreases. Muscle density EBV had a positive regression with shear force and the novel toughness sensory traits (P < 0.05). Selection for HMD EBV's increased shear force and toughness traits, which is unfavourable for the consumer. Low muscle density sired meat had higher meat colour traits chroma/saturation (+0.64, SD 2.30, P = 0.012), redness (+0.52, SD 1.91, P = 0.012) and yellowness (+0.31, SD 1.49, P = 0.08) compared to HMD sired meat. Selection for LMD could be used within a breeding programme to increase IMF content and enhance both meat colour and improve eating quality parameters.


Assuntos
Carne , Músculo Esquelético , Tecido Adiposo , Animais , Ácidos Graxos Insaturados , Masculino , Carne/análise , Valor Nutritivo , Ovinos , Carneiro Doméstico
4.
Transplant Proc ; 50(10): 3552-3558, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30577236

RESUMO

Thromboelastography (TEG) is a viscoelastic test that allows rapid evaluation of clot formation and fibrinolysis from a sample of whole blood. TEG is increasingly utilized to guide blood product resuscitation in surgical patients and transfusions for liver transplant patients. Patients with severe liver failure have significant derangement of their clotting function due to impaired production of procoagulant and anticoagulant factors. Traditional coagulation studies are limited by the short time needed for the result and provide little information about the dynamics and strength of clot formation. In addition, traditional coagulation studies do not correlate well with bleeding episodes and may lead to over-transfusion of various blood products. Evidence is less robust regarding the use of TEG for transfusion management decisions in severe liver failure patients awaiting, undergoing, or immediately after liver transplant surgery. However, the available evidence suggests that systematic implementation of TEG rather than traditional coagulation studies results in the administration of fewer blood products without increased mortality or complications. The purpose of this study is to review the literature regarding the use of TEG in liver failure patients prior to liver transplant, intraoperatively, and postoperatively. Additional high-quality randomized controlled studies should be performed to evaluate the use of TEG to guide transfusion decisions, particularly in the postoperative period following liver transplantation.


Assuntos
Transplante de Fígado/métodos , Tromboelastografia/métodos , Feminino , Humanos , Pessoa de Meia-Idade
5.
Radiat Prot Dosimetry ; 176(1-2): 45-49, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-27288356

RESUMO

For the first time, plutonium retention in human upper airways was investigated based on the dosimetric structure of the human respiratory tract proposed by the International Commission on Radiological Protection (ICRP). This paper describes analytical work methodology, case selection criteria, and summarizes findings on soluble (ICRP 68 Type M material) plutonium distribution in the lungs of a former nuclear worker occupationally exposed to plutonium nitrate [239Pu(NO3)4]. Thirty-eight years post-intake, plutonium was found to be uniformly distributed between bronchial (BB), bronchiolar (bb) and alveolar-interstitial (AI) dosimetric compartments as well as between the left and right lungs. 239+240Pu and 238Pu total body activity was estimated to be 2333 ± 23 and 42.1 ± 0.7 Bq, respectively. The results of this work provide key information on the extent of plutonium binding in the upper airways of the human respiratory tract.

6.
Case Rep Pediatr ; 2014: 696703, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24707424

RESUMO

We present a case of a 3-year-old boy with neurodegeneration. Family history reveals Rendu-Osler-Weber disease. Magnetic resonance imaging (MRI) of the spinal cord and spinal angiography showed a spinal arteriovenous fistula with venous aneurysm, causing compression of the lumbar spinal cord. Embolisation of the fistula was executed, resulting in clinical improvement. A week after discharge he was readmitted with neurologic regression. A second MRI scan revealed an intraspinal epidural haematoma and increase in size of the aneurysm with several new arterial feeders leading to it. Coiling of the aneurysm and fistulas was performed. Postoperative, the spinal oedema increased despite corticoids, causing more extensive paraplegia of the lower limbs and a deterioration of his mental state. A laminectomy was performed and the aneurysm was surgically removed. Subsequently, the boy recovered gradually. A new MRI scan after two months showed less oedema and a split, partly affected spinal chord. This case shows the importance of excluding possible arteriovenous malformations in a child presenting with progressive neurodegeneration. In particular when there is a family history for Rendu-Osler-Weber disease, scans should be performed instantly to rule out this possibility. The case also highlights the possibility of good recovery of paraplegia in paediatric Rendu-Osler-Weber patients.

7.
Health Phys ; 100 Suppl 2: S79-91, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21451312

RESUMO

Factors affecting the random and systematic error in calibrating three sets of 100 LiF:Mg,Ti thermoluminescent detector chips were investigated. The chips were held in a polymethyl methacrylate plate with 0.3 cm deep wells covered with a thin top plate, affixed to a polymethyl methacrylate phantom 150 cm from a 3.2 × 10(10) GBq 137Cs source, used to irradiate the chips to 4.52 mGy. Three sets of chips were used: one new, one heavily used, and one having relatively high degrees of visible physical damage. Variations in the exposure rate across the plate were measured with an ion chamber. Experimental drift was judged by performing successive calibrations on subsequent days, while always reading the chips in the same order. The chips were subject to manual examination to determine variations in mass and physical quality. This study indicates that more accurate calibrations can be obtained by accounting for the error caused by nonuniformity in the delivered dose, which was in this study as high as 4.4% from the center to the edges of the target. Making use of more than three calibrations only reduces the standard deviation as a percentage of the mean of a set by less than 1%. Desirable dosimeters in commercially rejected sets were identified by comparing each dosimeter's standard deviation of response across all calibrations to a commercially acceptable control set. Up to 50% variations in mass and visual quality, including opacity, fracture, and surface scratches to chips, showed little to no correlation with their response.


Assuntos
Dosimetria Termoluminescente/instrumentação , Dosimetria Termoluminescente/estatística & dados numéricos , Reutilização de Equipamento/estatística & dados numéricos , Física Médica , Humanos , Proteção Radiológica
8.
Physiol Meas ; 31(7): 1047-64, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20585148

RESUMO

A real-time neonatal seizure detection system is proposed based on a Gaussian mixture model classifier. The system includes feature transformation techniques and classifier output postprocessing. The detector was evaluated on a database of 20 patients with 330 h of recordings. A detailed analysis of the choice of parameters for the detector is provided. A mean good detection rate of 79% was obtained with only 0.5 false detections per hour. A thorough review of all misclassified events was performed, from which a number of patterns causing false detections were identified.


Assuntos
Eletroencefalografia/métodos , Modelos Neurológicos , Convulsões/classificação , Artefatos , Eletrodos , Reações Falso-Positivas , Humanos , Recém-Nascido , Movimento , Distribuição Normal , Curva ROC , Processamento de Sinais Assistido por Computador
9.
Artigo em Inglês | MEDLINE | ID: mdl-19162803

RESUMO

The goal of neonatal seizure detection is the development of a patient independent system to alert staff in the neonatal intensive care unit of ongoing seizures. This study demonstrates the potential in adapting a patient independent classifier using patient specific data. Supervised adaptation is investigated using the basic gradient descent algorithm and least mean squares procedures. An increase in mean ROC area of 3% is obtained for the best performing learning algorithm, yielding an increase in mean accuracy of 7.7% compared to the patient independent algorithm.


Assuntos
Algoritmos , Inteligência Artificial , Diagnóstico por Computador/métodos , Eletroencefalografia/métodos , Reconhecimento Automatizado de Padrão/métodos , Convulsões/diagnóstico , Humanos , Recém-Nascido , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
J Biol Rhythms ; 15(2): 126-34, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10762031

RESUMO

Entrainment of circannual rhythms of body mass and reproduction was monitored for 3 years in female golden-mantled ground squirrels maintained in a simulated natural photoperiod. Both pinealectomized and pineal-intact squirrels generated circannual rhythms of body mass and estrus, but only the intact animals entrained these rhythms to a period of 365 days. In the second and third years after treatment, the period of the body mass rhythm was significantly shorter than 365 days for pinealectomized squirrels, and variance in tau among these animals was significantly greater than for intact squirrels. A similar pattern was evident in the rhythm of reproduction, which was phase-disrupted in pinealectomized squirrels but entrained in intacts. Seasonal changes in duration of nocturnal melatonin secretion by the pineal appear to be necessary to produce phase-delays required to entrain the circannual clock to a period of 12 months.


Assuntos
Luz , Glândula Pineal/fisiologia , Sciuridae/fisiologia , Estações do Ano , Animais , Peso Corporal/fisiologia , Feminino , Melatonina/sangue , Concentração Osmolar , Fotoperíodo , Reprodução/fisiologia , Reprodução/efeitos da radiação , Sciuridae/sangue
11.
Cancer Control ; 7(2): 157-64, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10783820

RESUMO

BACKGROUND: Pain is often poorly controlled in cancer patients. Chronic pain affects adult patients at all stages of cancer management. Optimal pain management may require attention to psychosocial variables and the inclusion of nonpharmacological techniques. METHODS: Three nonpharmacological strategies that are effective in reducing pain caused by cancer--patient psycho-education, supportive psychotherapy, and cognitive-behavioral interventions--are reviewed. Recommendations for physicians to facilitate a mental health referral are also discussed. RESULTS: Effective treatment of cancer pain begins with assessing the severity, characteristics, and impact of pain. Emotional distress (especially anxiety, depression, and beliefs about pain) has emerged as predictive of patient pain levels. Appropriate pain management may require a multidisciplinary approach. CONCLUSIONS: Patient psycho-education has empowered patients to actively participate in pain control strategies. Supportive psychotherapy can assist patients in managing the stressors associated with cancer, and cognitive-behavioral therapy helps patients to recognize and modify the factors that contribute to physical and emotional distress.


Assuntos
Terapia Cognitivo-Comportamental , Neoplasias/fisiopatologia , Manejo da Dor , Dor/psicologia , Educação de Pacientes como Assunto , Psicoterapia , Adulto , Humanos , Saúde Mental , Dor/etiologia , Medição da Dor , Encaminhamento e Consulta , Apoio Social , Estresse Psicológico
12.
Bioorg Med Chem Lett ; 9(12): 1727-32, 1999 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-10397509

RESUMO

Following our discovery of the strong binding of thiadiazole 1 to the AF-2 neuropeptide receptor of gastrointestinal nematodes (e.g., Ascaris suum), we prepared two series of analogs. Only the series containing the thiadiazole ring had potencies comparable to that of compound 1. Analog 50 exhibited an apparent potency in the AF-2 binding assay 300 times that of compound 1.


Assuntos
Anti-Helmínticos/síntese química , Proteínas de Helminto/metabolismo , Neuropeptídeos/metabolismo , Tiadiazóis/síntese química , Animais , Anti-Helmínticos/química , Anti-Helmínticos/farmacologia , Ascaris suum , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Proteínas de Helminto/efeitos dos fármacos , Neuropeptídeos/efeitos dos fármacos , Relação Estrutura-Atividade , Tiadiazóis/química , Tiadiazóis/farmacologia
13.
Vet Parasitol ; 80(2): 127-36, 1998 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-9870365

RESUMO

An in vitro method for testing activity of buparvaquone in serum on the infection and development of Theileria in its bovine host mononuclear cells is described and results compared with the effect exhibited in vivo. Serum samples were collected over a time course from calves in a clinical trial of 5 mg kg(-1) buparvaquone prophylaxis on Theileria annulata or T. parva experimental infection. To evaluate drug levels and persistence in each animal for a period of 14 days and its effect on the early infection stages, the sera were tested on established macroschizont infected cell lines and against the in vitro infection and development process of the sporozoite and trophozoite stages of the two Theileria species. Results from the in vitro assays show that buparvaquone in serum can completely prevent the establishment of Theileria infection during the first 48 h after administration at 5 mg kg(-1). After seven days, levels are sufficient to delay the establishment of infection. The drug is more effective in the prevention of the de novo development of the parasite in cells than against established macroschizont infected cell culture. At low concentrations, it is more effective against T. parva than against T. annulata. Drug effect peaks during the first 24 h but residual effect persists for 14 days, particularly against T. parva infection. These novel findings demonstrate how high doses of buparvaquone could over-protect calves if used in the 'infection-and-treatment' method of immunisation when drug is administered prophylactically at the same time as infection with live sporozoites. It is suggested that in certain high Theileria risk situations there may be potential for the immunoprophylactic use of buparvaquone without simultaneous infection. The in vitro assay itself has been shown to be of value as a model for Theileria establishment in cattle.


Assuntos
Antiprotozoários/farmacologia , Naftoquinonas/farmacologia , Theileria annulata/crescimento & desenvolvimento , Theileria parva/crescimento & desenvolvimento , Theileriose/prevenção & controle , Animais , Antiprotozoários/uso terapêutico , Bioensaio/veterinária , Bovinos , Linhagem Celular , Naftoquinonas/uso terapêutico , Theileria annulata/efeitos dos fármacos , Theileria parva/efeitos dos fármacos , Theileriose/tratamento farmacológico , Fatores de Tempo
14.
J Vet Pharmacol Ther ; 21(3): 190-8, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9673959

RESUMO

PNU-87407 and PNU-88509, beta-ketoamide anthelmintics that are structurally related to each other and to the salicylanilide anthelmintic closantel, exhibit different anthelmintic spectra and apparent toxicity in mammals. The basis for this differential pharmacology was examined in experiments that measured motility and adenosine triphosphate (ATP) levels in larval and adult stages of the gastrointestinal nematode, Haemonchus contortus, and in a vertebrate liver cell line and mitochondria. PNU-87407 and PNU-88509 both exhibited functional cross-resistance with closantel in larval migration assays using closantel-resistant and -sensitive isolates of H. contortus. Each compound reduced motility and ATP levels in cultured adult H. contortus in a concentration- and time-dependent manner; however, motility was reduced more rapidly by PNU-88509, and ATP levels were reduced by lower concentrations of closantel than the beta-ketoamides. Tension recordings from segments of adult H. contortus showed that PNU-88509 induces spastic paralysis, while PNU-87407 and closantel induce flaccid paralysis of the somatic musculature. Marked differences in the actions of these compounds were also observed in the mammalian preparations. In Chang liver cells, ATP levels were reduced after 3 h exposures to > or = 0.25 microM PNU-87407, > or = 1 microM closantel or > or = 10 microM PNU-88509. Reductions in ATP caused by PNU-88509 were completely reversible, while the effects of closantel and PNU-87407 were irreversible. PNU-87407, closantel and PNU-88509 uncoupled oxidative phosphorylation in isolated rat liver mitochondria, inhibiting the respiratory control index (with glutamate or succinate as substrate) by 50% at concentrations of 0.14, 0.9 and 7.6 microM, respectively.


Assuntos
Anti-Helmínticos/farmacologia , Haemonchus/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Salicilanilidas/farmacologia , Desacopladores/farmacologia , Trifosfato de Adenosina/metabolismo , Amidas , Animais , Anti-Helmínticos/administração & dosagem , Linhagem Celular , Relação Dose-Resposta a Droga , Feminino , Haemonchus/fisiologia , L-Lactato Desidrogenase/análise , Larva/efeitos dos fármacos , Larva/fisiologia , Mitocôndrias Hepáticas/metabolismo , Fosforilação Oxidativa , Ratos , Trichostrongylus/efeitos dos fármacos , Trichostrongylus/fisiologia
15.
Exp Parasitol ; 87(3): 171-84, 1997 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9371082

RESUMO

Polyamines (PA) are essential for viability and replication of all cells; organisms either synthesize PA or acquire them from the environment. How nematodes that parasitize the gut satisfy their PA requirement has not been resolved. The primary regulatory enzyme in PA biosynthesis in most animals is ornithine decarboxylase (ODC). This enzyme has recently been characterized in free-living nematodes and in the parasitic species. Haemonchus contortus. Nematode and mammalian ODC are reported to differ in subcellular localization, kinetics, and sensitivity to inhibitors. We cloned an H. contortus cDNA that encodes a full-length ODC (sequence data from this article have been deposited with the GenBank Data Library under Accession Nos. AF016538 and AF016891). This cDNA was functionally expressed in strains of Escherichia coli and Saccharomyces cerevisiae that lack ODC and are dependent upon exogenous PA for survival. Expression of nematode ODC reversed the PA-dependence phenotype of both microorganisms. The complemented yeast strain was used to develop a nutrient-dependent viability screen for selective inhibitors of nematode ODC. The antiprotozoal drug stilbamidine isethionate was identified as active in this screen, but biochemical characterization revealed that this compound did not inhibit ODC. Instead, like other cationic diamidines, stilbamidine probably inhibits yeast S-adenosylmethionine decarboxylase. Nonetheless, the activity in the screen of the known ODC inhibitor difluoromethylornithine (DFMO) validates the concept that specific recombinant microorganisms can serve as the basis for extremely selective and facile screens.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Haemonchus/enzimologia , Inibidores da Ornitina Descarboxilase , Estilbamidinas/farmacologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , DNA Complementar/genética , Inibidores Enzimáticos , Escherichia coli/genética , Teste de Complementação Genética , Haemonchus/genética , Proteínas de Helminto/efeitos dos fármacos , Dados de Sequência Molecular , Ornitina Descarboxilase/genética , Poliaminas/metabolismo , Proteínas Recombinantes/biossíntese , Saccharomyces cerevisiae/genética , Seleção Genética , Homologia de Sequência de Aminoácidos
17.
Int J Parasitol ; 26(1): 25-35, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9198593

RESUMO

To determine if a cuticle microenvironment pH is maintained by adult Haemonchus contortus, organic acid excretion kinetics and absorption kinetics of selected model weak acids and a weak base were measured in incubation media that varied in buffer capacity (0.25-20 mM HEPES or 5 mM glycine) and initial pH (7.5 or 3.5). To evaluate the importance of the cuticle as a pathway for organic acid excretion and drug absorption the pharynx was paralyzed with 1 nM ivermectin. H. contortus changed the media pH from initial values of 7.5 or 3.25 to an asymptotic value of approximately 5.6. The rate of pH change depended on the buffer capacity, but was not affected by chemical ligation with ivermectin. The intrinsic rate of excretion of organic acids (0.045 +/- 0.016 micromol/cm2 x h) was constant during the first 8-12 h of incubation and was independent of initial pH, buffer capacity or ivermectin ligation. The rates of absorption of the model weak acids, benzoic acid and p-nitrophenol, and the model weak base, aniline, were not affected by initial pH, buffer capacity or ivermectin ligation. These results suggest that H. contortus excretes organic acid endproducts of carbohydrate metabolism across its cuticle, and that these acids maintain a microenvironment pH within the water-filled pores of the cuticle that controls the rate of adsorption of weakly acidic or basic drugs.


Assuntos
Compostos de Anilina/metabolismo , Benzoatos/metabolismo , Haemonchus/metabolismo , Nitrofenóis/metabolismo , Absorção , Ácidos/metabolismo , Álcalis/metabolismo , Animais , Anti-Helmínticos/metabolismo , Ácido Benzoico , Transporte Biológico , Feminino , Concentração de Íons de Hidrogênio , Ivermectina/metabolismo
18.
J Antibiot (Tokyo) ; 48(8): 820-3, 1995 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7592027

RESUMO

A novel cyclodepsipeptide of fungal origin, PF1022A, recently was reported to have anthelmintic activity. To supplement published reports and determine potential utility of PF1022A as a ruminant anthelmintic, the compound was examined in in vitro and in vivo models. Assays used measured motility of Haemonchus contortus (intrinsic drug potency), ATP levels (parasite death), and activity against H. contortus, Ostertagia ostertagi, and Trichostrongylus colubriformis in the jird (spectrum, potency, and efficacy by various routes). The potency of PF1022A in reducing motility is greater than commercial anthelmintics. Examination of ATP levels in PF1022A-paralyzed H. contortus indicates that worms are not killed, suggesting the compound acts as a neurotoxin in nematodes. In the jird, PF1022A has activity orally against each of the parasites studied and at doses comparable to all commercial anthelmintics, except the macrocyclic lactones which are more potent. Unfortunately, for some nematode species, parenteral delivery is ineffective at realistic doses.


Assuntos
Anti-Helmínticos/uso terapêutico , Depsipeptídeos , Hemoncose/tratamento farmacológico , Peptídeos Cíclicos/uso terapêutico , Trifosfato de Adenosina/metabolismo , Administração Oral , Animais , Feminino , Gerbillinae , Haemonchus/efeitos dos fármacos , Estrutura Molecular , Ostertagia/efeitos dos fármacos , Trichostrongylus/efeitos dos fármacos
19.
Thromb Haemost ; 72(6): 793-8, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7740443

RESUMO

Dermatan sulphate catalyses thrombin inhibition by heparin cofactor II; it has a lower haemorrhagic to antithrombotic ratio than that of heparin in animal models. Consecutive patients aged forty years or more, electively undergoing total hip replacement under general anaesthesia, were randomly allocated to one of three dosage regimens of dermatan sulphate (MF701, Mediolanum Farmaceutici) given intramuscularly. These were 200 mg once daily (n = 50), 200 mg twice daily (n = 52) and 300 mg twice daily (n = 51), administered from twenty-four hours pre-operatively until the tenth postoperative day. The overall incidence of DVT assessed by bilateral venography was 53%, 51% and 34% respectively (Chi-square test for trend p = 0.06). The incidence of major proximal DVT was 10.6%, 8.5% and 2.1% respectively. Pulmonary embolism (PE) and bleeding were assessed in all 153 patients. There was one case of PE in each dose group. The incidence of bleeding episodes, volume of blood lost and blood transfusion requirements were low and showed no increase with increasing dose. The patients were followed up 4-8 weeks after discharge. We conclude that the two lower doses were subtherapeutic in this population, however dermatan sulphate given 300 mg twice daily, proved to be efficacious with an incidence of proximal major DVT of 2.1% and a low incidence of bleeding complications. A trial of dermatan sulphate 300 mg twice daily compared to standard prophylactic agents is needed.


Assuntos
Dermatan Sulfato/uso terapêutico , Prótese de Quadril/efeitos adversos , Tromboflebite/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Perda Sanguínea Cirúrgica , Relação Dose-Resposta a Droga , Estudos de Avaliação como Assunto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Flebografia , Complicações Pós-Operatórias/mortalidade , Embolia Pulmonar/etiologia , Valores de Referência , Fatores de Risco , Tromboflebite/etiologia
20.
J Pharm Sci ; 83(7): 1052-9, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7965664

RESUMO

This multidisciplinary study demonstrates the utility of the biophysical model approach to assess biological activity of anthelmintics in light of drug-delivery principles. The relationships between drug absorption and efficacy for a set of structurally disparate anthelmintics were determined in cultures of Haemonchus contortus, a nematode that parasitizes the ruminant gastrointestinal tract. Uptake, parameterized by the permeability coefficient, Pe, was shown to occur by absorption across the cuticle. Rates of drug appearance in nematode carcasses paralleled rates of drug disappearance from the medium, and absorption reached an apparent equilibrium within a few hours. The parasite/medium partition coefficient, K, was derived from the ratio of drug concentration in the parasite vs the medium at equilibrium. Pe and K values for each anthelmintic were correlated with lipophilicity (as measured by the partition coefficient (PC) in n-octanol/water) and both parameters plateaued at log PC approximately 2.5, with maximum Pe approximately 8 x 10(-4) cm/min and log K < or = 2.0. Absorption kinetics were related to in vitro potency by monitoring motility of H. contortus. The time required to reduce motility by 50% (t* 50) and Pe were used to calculate Cn*, the drug concentration in the parasite at t* 50, as an indicator of intrinsic potency. The quantitative interplay of apparent biological activity expressed as t* 50, dose, and intrinsic potency highlights the important contribution of drug-uptake kinetics.


Assuntos
Anti-Helmínticos/química , Anti-Helmínticos/farmacologia , Haemonchus/efeitos dos fármacos , Haemonchus/metabolismo , Modelos Biológicos , Modelos Químicos , Absorção , Animais , Anti-Helmínticos/farmacocinética , Transporte Biológico , Físico-Química/métodos , Feminino , Cinética , Relação Estrutura-Atividade
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