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1.
Epilepsy Res ; 192: 107129, 2023 05.
Article in English | MEDLINE | ID: mdl-36958107

ABSTRACT

Presurgical evaluation of refractory epilepsy involves functional investigations to minimize postoperative deficit. Assessing language and memory is conventionally undertaken using Wada and fMRI, and occasionally supplemented by data from invasive intracranial electroencephalography, such as electrical stimulation, corticortical evoked potentials, mapping of high frequency activity and phase amplitude coupling. We describe the comparative and complementary role of these methods to inform surgical decision-making and functional prognostication. We used Wada paradigm to standardize testing across all modalities. Postoperative neuropsychological testing confirmed deficit predicted based on these methods.


Subject(s)
Drug Resistant Epilepsy , Epilepsy , Humans , Epilepsy/diagnostic imaging , Epilepsy/surgery , Magnetic Resonance Imaging , Electrocorticography , Drug Resistant Epilepsy/diagnostic imaging , Drug Resistant Epilepsy/surgery , Electric Stimulation , Electroencephalography
2.
Curr Med Chem ; 19(4): 613-24, 2012.
Article in English | MEDLINE | ID: mdl-22204334

ABSTRACT

The inbuilt 2-N-hydroxy-1-oxo-3-carboxylic acid of isoquinolone was designed as pyrophosphate mimic for hepatitis C NS5B polymerase. Various 2-hydroxy-1-oxo-1,2-dihydroisoquinoline-3-carboxylic acid derivatives 11a-p were synthesized and evaluated as HCV NS5B polymerase inhibitors. Compound 11c exhibited moderate inhibitory potency based on the inorganic pyrophosphate generation (IC50 = 9.5 µM) and based on NTP incorporation by NS5B enzyme (IC50 = 5.9 µM). Compound 11c demonstrated antiviral activity (EC50 = 15.7 µM) and good selectivity in HCV genotype 1b replicon Ava.5 cells. Compound 11c reduced the interaction of NTP to NS5B polymerase. Docking model showed that 11c situated in similar orientation to the bound uridine triphosphate in the active site of NS5B polymerase. As a result, 2-hydroxy-1-oxo-1,2-dihydroisoquinoline-3-carboxylic acid was disclosed as a novel inbuilt ß-N-Hydroxy-γ-keto-acid pharmacophore for HCV NS5B polymerase inhibitors.


Subject(s)
Carboxylic Acids/pharmacology , Enzyme Inhibitors/pharmacology , Isoquinolines/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Carboxylic Acids/chemical synthesis , Carboxylic Acids/chemistry , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Isoquinolines/chemical synthesis , Isoquinolines/chemistry , Keto Acids , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Viral Nonstructural Proteins/metabolism
3.
BJOG ; 118(7): 825-31, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21401854

ABSTRACT

OBJECTIVE: To investigate anti-müllerian hormone (AMH) as a best test of ovarian reserve in women with transfusion-dependent ß-thalassaemia, and the relationship between AMH and iron overload. DESIGN AND SETTING: A case-control study in a tertiary medical centre. POPULATION: Twenty-nine women with transfusion-dependent ß-thalassaemia and 29 healthy controls of a similar age were recruited. METHODS: Blood sampling, questionnaires and medical record reviews were used. MAIN OUTCOME MEASURES: The history of iron overload-related morbidities, haematological phenotypes, serum levels of AMH and ferritin, and hormonal profiles were analysed. RESULTS: The serum levels of AMH, luteinising hormone, and estradiol were lower in women with transfusion-dependent ß-thalassaemia than in age-matched normal controls. In women with transfusion-dependent ß-thalassaemia, the serum AMH level was significantly inversely related to the ferritin level, but not related to the presence of hypogonadotrophic hypogonadism, diabetes and haematological phenotypes. The serum ferritin level was positively associated with advanced age and the presence of hypogonadotrophic hypogonadism in the study participants. However, the inverse relationship between AMH and ferritin still exists after further adjustment for advanced age in women with transfusion-dependent ß-thalassaemia. CONCLUSIONS: The present study indicates that the serum AMH levels in women with transfusion-dependent ß-thalassaemia are lower when compared with normal healthy women of a similar age, and are significantly negatively correlated with their serum ferritin levels. This implies that ovarian function might be impaired by the chronic iron overload status in women with transfusion-dependent ß-thalassaemia.


Subject(s)
Anti-Mullerian Hormone/blood , Blood Transfusion , Iron Overload/blood , beta-Thalassemia/blood , beta-Thalassemia/therapy , Adolescent , Adult , Anti-Mullerian Hormone/deficiency , Biomarkers/blood , Case-Control Studies , Child , Female , Ferritins/blood , Hospitals, University , Humans , Predictive Value of Tests , Prognosis , Risk Factors , Sensitivity and Specificity , Surveys and Questionnaires
4.
Curr Med Chem ; 17(32): 3806-26, 2010.
Article in English | MEDLINE | ID: mdl-20858218

ABSTRACT

Hepatitis C virus (HCV), a causative agent for non-A and non-B hepatitis, has infected approximately 3% of world's population. The current treatment option of ribavirin in combination with pegylated interferon possesses lower sustained virological response rates, and has serious disadvantages. Unfortunately, no prophylactic vaccine has been approved yet. Therefore, there is an unmet clinical need for more effective and safe anti-HCV drugs. HCV NS5B RNA dependent RNA polymerase is currently pursued as the most popular target to develop safe anti-HCV agents, as it is not expressed in uninfected cells. More than 25 pharmaceutical companies and some research groups have developed ≈50 structurally diverse scaffolds to inhibit NS5B. Here we provide comprehensive account of the drug development process of these scaffolds. NS5B polymerase inhibitors have been broadly classified in nucleoside and non nucleoside inhibitors and are sub classified according to their mechanism of action and structural diversities. With some additional considerations about the inhibitor bound NS5B enzyme X-ray crystal structure information and pharmacological aspects of the inhibitors, this review summarizes the lead identification, structure activity relationship (SAR) studies leading to the most potent NS5B inhibitors with subgenomic replicon activity.


Subject(s)
Antiviral Agents/chemistry , Enzyme Inhibitors/chemistry , Hepatitis C/drug therapy , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Viral Nonstructural Proteins/antagonists & inhibitors , Amides/chemistry , Amides/therapeutic use , Antiviral Agents/therapeutic use , Azoles/chemistry , Azoles/therapeutic use , Clinical Trials as Topic , Enzyme Inhibitors/therapeutic use , Humans , Nucleosides/chemistry , Nucleosides/therapeutic use , Pyrimidines/chemistry , Pyrimidines/therapeutic use , RNA-Dependent RNA Polymerase/metabolism , Viral Nonstructural Proteins/metabolism
5.
Clin Exp Obstet Gynecol ; 34(4): 207-11, 2007.
Article in English | MEDLINE | ID: mdl-18225679

ABSTRACT

PURPOSE: To propose a novel concept that progesterone receptor antagonists, e.g., mifepristone, may prove effective in treating a variety of cancers--even those not shown to be hormonally dependent or possessing progesterone receptors. METHODS: Multiple human leukemia cell lines were evaluated for mRNA expression of an immunomodulatory protein called the progesterone-induced blocking factor (PIBF) that suppresses natural killer (NK) cell activity during normal pregnancy. Furthermore, we evaluated the effects of progesterone (P) and mifepristone in PIBF protein expression. Finally, the effect of mifepristone treatment of mice with advanced leukemia was evaluated. RESULTS: All tumor cell lines evaluated were found to express mRNA for PIBF and some were found to even express the PIBF protein. The addition of P to the media increased the expression of PIBF and mifepristone downregulated its expression. Treatment of mice with spontaneous leukemia when they already had extensive disease seemed to increase the length and quality of their life. CONCLUSIONS: These data and other experience with mice with lung cancer and some anecdotal human cancer experience suggest that various cancers may utilize similar mechanisms used by the fetus to escape NK cell surveillance. Mifepristone and other progesterone receptor antagonists may deserve a clinical trial in human cancer even where there is no knowledge of the presence of progesterone receptors.


Subject(s)
Hormone Antagonists/pharmacology , Killer Cells, Natural/drug effects , Leukemia/drug therapy , Mifepristone/pharmacology , Pregnancy Proteins/drug effects , Receptors, Progesterone/antagonists & inhibitors , Animals , Cell Line, Tumor , Humans , Mice , Pregnancy Proteins/metabolism , Progesterone/physiology , RNA, Messenger/drug effects , Suppressor Factors, Immunologic
6.
Bone Marrow Transplant ; 37(6): 569-74, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16462756

ABSTRACT

The thalassemias are a heterogeneous group of inherited hypochromic anemias of varying severity. The mainstay of supportive treatment is regular blood transfusion accompanied by iron-chelating therapy. Hematopoietic stem cell transplantation (HSCT) provides an alternative option when curative therapy is considered. More than 400 patients in Taiwan have beta-thalassemia major or other transfusion-dependent thalassemias, and their treatment costs account for a considerable percentage of the National Health Insurance expenditure. In this report, we estimated the treatment costs of conventional therapy (regular blood transfusion accompanied by iron-chelating agents) and HSCT. The undiscounted medical cost of 20 years of follow-up (20 years from diagnosis) and the undiscounted total lifetime cost were NT$ 4 739 888 (NT$ means New Taiwan Dollars)/US$ 149 288 and NT$ 11 529 990/US$ 363 149, respectively, for patients undergoing conventional therapy, and NT$ 2 639 982/US$ 83 149 and NT$ 3 511 172/US$ 110 588, respectively, for those undergoing successful HSCT. Comparisons of treatment costs and other parameters between these two modalities can add to the information base on which policy is made by health authorities or clinicians.


Subject(s)
Blood Transfusion/economics , Cost of Illness , Stem Cell Transplantation/economics , beta-Thalassemia/economics , beta-Thalassemia/therapy , Child, Preschool , Disease-Free Survival , Female , Fetal Blood/cytology , Follow-Up Studies , Histocompatibility Testing , Humans , Infant , Male , Siblings , Taiwan , Time Factors
7.
Br J Cancer ; 86(10): 1634-8, 2002 May 20.
Article in English | MEDLINE | ID: mdl-12085215

ABSTRACT

Cancer chemotherapy is limited by the modest therapeutic index of most antineoplastic drugs. Some glucuronide prodrugs may display selective anti-tumour activity against tumours that accumulate beta-glucuronidase. We examined the toxicity and anti-tumour activity of 9-aminocamptothecin glucuronide, a new glucuronide prodrug of 9-aminocamptothecin, to evaluate its potential clinical utility. 9-aminocamptothecin glucuronide was 25-60 times less toxic than 9-aminocamptothecin to five human cancer cell lines. Beta-glucuronidase activated 9-aminocamptothecin glucuronide to produce similar cell killing as 9-aminocamptothecin or topotecan. The in vivo toxicity of 9-aminocamptothecin glucuronide in BALB/c mice was dose-, route-, sex- and age-dependent. 9-aminocamptothecin glucuronide was significantly less toxic to female than to male mice but the difference decreased with age. 9-aminocamptothecin glucuronide and 9-aminocamptothecin produced similar inhibition (approximately 80%) of LS174T human colorectal carcinoma tumours. 9-aminocamptothecin glucuronide cured a high percentage of CL1-5 human lung cancer xenografts with efficacy that was similar to or greater than 9-aminocamptothecin, irinotecan and topotecan. The potent anti-tumour activity of 9-aminocamptothecin glucuronide suggests that this prodrug should be further evaluated for cancer treatment.


Subject(s)
Antineoplastic Agents/therapeutic use , Camptothecin/therapeutic use , Glucuronides/therapeutic use , Prodrugs/therapeutic use , Adenocarcinoma/drug therapy , Adenocarcinoma/pathology , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/toxicity , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Camptothecin/analogs & derivatives , Camptothecin/pharmacology , Camptothecin/toxicity , Drug Stability , Female , Glucuronides/pharmacokinetics , Glucuronides/pharmacology , Glucuronides/toxicity , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/pathology , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/pathology , Prodrugs/pharmacology , Prodrugs/toxicity , Sex Factors , Solubility , Topotecan/pharmacology , Topotecan/toxicity , Tumor Cells, Cultured/drug effects , Weight Loss , Xenograft Model Antitumor Assays
8.
J Med Chem ; 44(23): 3759-63, 2001 Nov 08.
Article in English | MEDLINE | ID: mdl-11689062

ABSTRACT

A hypothetical pharmacophore of 5 alpha-reductase inhibitors was generated and served as a template in virtual screening. When the pharmacophore was used, eight isoflavone derivatives were characterized as novel potential nonsteroidal inhibitors of rat 5 alpha-reductase. This investigation has demonstrated a practical approach toward the development of lead compounds through a hypothetic pharmacophore via three-dimensional database searching.


Subject(s)
5-alpha Reductase Inhibitors , Enzyme Inhibitors/chemistry , Isoflavones/chemistry , 3-Oxo-5-alpha-Steroid 4-Dehydrogenase/chemistry , Animals , Binding Sites , Databases, Factual , Enzyme Inhibitors/pharmacology , In Vitro Techniques , Isoflavones/pharmacology , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Models, Molecular , Rats , Structure-Activity Relationship
9.
Mol Pharmacol ; 60(6): 1439-48, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11723253

ABSTRACT

Because the transcription factor, nuclear factor (NF)-kappaB, plays a key role in cellular inflammatory and immune responses, components of the NF-kappaB-activating signaling pathways are frequently used as targets for anti-inflammatory agents. This study shows that 2-(3',4'-dihydroxyphenyl)-5-hydroxybenzo[b]furan (GF-015) and 2,3-di(3',4'-dihydroxy-transstyryl) pyridine (GF-90), two conjugated polyhydroxybenzene derivatives, inhibited a common step in NF-kappaB activation in human NCI-H292 epithelial cells by preventing tumor necrosis factor (TNF)-alpha- and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced IkappaB kinase (IKK) complex activation. Both agents inhibited the TNF-alpha- or TPA-induced expression of cyclooxygenase (COX)-2 mRNA and protein, COX-2 promoter activity, and prostaglandin E2 (PGE2) production. Overexpression of wild-type NF-kappaB-inducing kinase, IKKalpha, and IKKbeta led, respectively, to 3.5-, 2.6-, and 2.6-fold increases in COX-2 promoter activity, and these effects were inhibited by both compounds. GF-015 and GF-90 also prevented the TNF-alpha- and TPA-induced activation of IKK and NF-kappaB-specific DNA-protein binding activity. These results suggest that the inhibitory effect of GF-015 and GF-90 on TNF-alpha-induced COX-2 protein expression was caused by suppression of IKK activity and NF-kappaB activation in the COX-2 promoter, resulting in attenuation of COX-2 gene expression and PGE2 production.


Subject(s)
Anti-Inflammatory Agents/pharmacology , Benzofurans/pharmacology , I-kappa B Proteins , Isoenzymes/genetics , NF-kappa B/metabolism , Prostaglandin-Endoperoxide Synthases/genetics , Protein Serine-Threonine Kinases/metabolism , Pyridines/pharmacology , Tumor Necrosis Factor-alpha/physiology , Cells, Cultured , Cyclooxygenase 2 , DNA/drug effects , DNA/metabolism , DNA-Binding Proteins/metabolism , Dinoprostone/metabolism , Enzyme Activation , Humans , I-kappa B Kinase , Isoenzymes/drug effects , Isoenzymes/metabolism , Membrane Proteins , NF-KappaB Inhibitor alpha , NF-kappa B/drug effects , Phosphorylation , Promoter Regions, Genetic/drug effects , Promoter Regions, Genetic/genetics , Prostaglandin-Endoperoxide Synthases/drug effects , Prostaglandin-Endoperoxide Synthases/metabolism , RNA, Messenger/drug effects , RNA, Messenger/metabolism , Tetradecanoylphorbol Acetate/pharmacology , Transcription, Genetic/drug effects , Tumor Necrosis Factor-alpha/drug effects
10.
J Cardiovasc Pharmacol ; 38(6): 893-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11707693

ABSTRACT

3-[[4-(2-Methoxyphenyl)piperazin-1-yl]methyl]-5-(methylthio)-2,3-dihydroimidazo[1,2-c]quinazoline (DL-017), a quinazoline derivative, exhibits alpha 1 -adrenoceptor antagonistic and type I antiarrhythmic effects on mammalian cardiac tissues. In the current study, the effects of DL-017 on the hemodynamic profile in anesthetized, spontaneously hypertensive rats were evaluated. Intravenous administration of DL-017 induced dose-dependent reductions of heart rate and blood pressure, which persisted over 2 h. DL-017 exerted a maximal antihypertensive effect at 0.1 mg/kg, which was similar to that of 0.1 mg/kg of prazosin. DL-017 was able to block the pressor response to phenylephrine but not to angiotensin II. Regional cerebral blood flow of the right parietal cortex decreased by 14 +/- 4% 10 min after bolus injection and then rapidly returned to control levels while the arterial pressure was still low. These results indicate that blockade of the alpha 1 -adrenoceptor by DL-017 contributes to reduction of arterial pressure. The antihypertensive effect without reflex tachycardia and loss of autoregulation of cerebral blood flow makes DL-017 suitable for chronic long-term treatment of hypertension.


Subject(s)
Adrenergic alpha-Agonists/pharmacology , Hypertension/drug therapy , Quinazolines/pharmacology , Animals , Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , Cerebral Cortex/blood supply , Cerebral Cortex/drug effects , Cerebrovascular Circulation/drug effects , Dose-Response Relationship, Drug , Heart Rate/drug effects , Kinetics , Laser-Doppler Flowmetry , Male , Phenylephrine/antagonists & inhibitors , Prazosin/pharmacology , Rats , Rats, Inbred SHR , Regional Blood Flow/drug effects , Vasoconstrictor Agents/antagonists & inhibitors
11.
Water Res ; 35(13): 3041-8, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11487098

ABSTRACT

A series of unsteady-state reaeration tests were performed in a 500-L tank at 0.81-4.58 m3/h diffused-air flow rate and 288-302 K water temperature. Three different types of impurities: soybean oil, surfactant, and diatomaceous earth were doped to simulate the impurities in wastewaters and the effects of the impurities on the oxygen transfer rate were investigated. The ASCE and the two-zone oxygen mass-transfer models were used to analyze the unsteady-state reaeration data and the volumetric mass-transfer coefficients determined from the unsteady-state reaeration data were correlated as a function of the diffused-air flow rate, water temperature, and impurity concentration. The results showed that the alpha factors based on the ASCE model are less sensitive to the impurity concentration while the presence of the impurities significantly reduces the alpha factors in the gas bubble zone. The saturation DO concentration and volumetric oxygen mass-transfer rate can be predicted by the two-zone model along with the correlation obtained in this study.


Subject(s)
Oxygen/chemistry , Water Pollutants, Chemical/metabolism , Water/chemistry , Atmospheric Pressure , Diatomaceous Earth/chemistry , Diffusion , Kinetics , Mathematics , Models, Chemical , Soybean Oil/chemistry , Surface-Active Agents/chemistry , Temperature
12.
Diabetes Care ; 24(5): 850-4, 2001 May.
Article in English | MEDLINE | ID: mdl-11347742

ABSTRACT

OBJECTIVE: To study the prevalence of and risk factors for abnormal glucose tolerance in transfusion-dependent beta-thalassemic patients. RESEARCH DESIGN AND METHODS: A total of 89 transfusion-dependent beta-thalassemic patients were interviewed. Diabetes was previously diagnosed in 14 of them. In the remaining 75 patients, 68 participated in an oral glucose tolerance test. Potential risk factors were identified using the independent t test, chi2 test, and Fisher's exact test. Logistic regression analysis was used to select the independent risk factors that best predicted abnormal glucose tolerance A two-tailed P value of <0.05 was considered to be statistically significant. RESULTS: The prevalence of impaired glucose tolerance was 8.5% (7 of 82) and that of diabetes was 19.5% (16 of 82). Presentation with diabetic ketoacidosis was 31.1% (5 of 16). The risk factors for abnormal glucose tolerance found in transfusion-dependent beta-thalassemic patients were serum ferritin concentration and hepatitis C infection. CONCLUSIONS: The interaction of iron overload and hepatitis C infection worsened the prognosis of thalassemic patients. Aggressive iron-chelation therapy as well as prevention and treatment of hepatitis C infection should be mandatory in managing glucose homeostasis in transfusion-dependent beta-thalassemic patients in Taiwan.


Subject(s)
Blood Transfusion , Glucose Intolerance/epidemiology , beta-Thalassemia/blood , beta-Thalassemia/therapy , Adolescent , Adult , Child , Diabetes Mellitus/epidemiology , Female , Ferritins/blood , Hepatitis B/epidemiology , Hepatitis C/epidemiology , Humans , Iron Chelating Agents/therapeutic use , Male , Patient Compliance , Prevalence , Risk Factors , Taiwan , beta-Thalassemia/complications
13.
Biotechnol Prog ; 17(1): 203-7, 2001.
Article in English | MEDLINE | ID: mdl-11170500

ABSTRACT

An expression vector characterized by tight regulation and high expression of cloned genes appears to be indispensable for the engineering need. To achieve this goal, in association with lacI the T7 A1 promoter containing two synthetic lac operators was constructed into a runaway-replication vector. To further examine this vector system, lacZ was subcloned and placed under the control of the T7 A1 promoter on the plasmid. With the application of the thermal induction alone, the Escherichia coli strain harboring the recombinant plasmid was able to produce 15,000 Miller units of beta-galactosidase, while it yielded the recombinant protein with 45,000-50,000 Miller units upon both thermal and chemical induction. In sharp contrast, only 60-90 Miller units of beta-galactosidase was obtained for the cell at an uninduced state. As a result, the production yield of beta-galactosidase over the background level is amplified approximately 170-fold by thermal induction and 500-fold by thermal and chemical induction. To produce the recombinant protein on a large scale, an approach by connecting two fermenters in series was newly developed. By applying the three-stage temperature shift in this dual fermenter system, 55,000 Miller units of beta-galactosidase was obtained. Overall, it shows the potential use of the vector system developed here for its tight control and high production of recombinant proteins.


Subject(s)
Bacteriophage T7/genetics , DNA Replication/genetics , Genetic Vectors , Lac Operon , Promoter Regions, Genetic , beta-Galactosidase/genetics , Base Sequence , Cloning, Molecular , Fermentation , Molecular Sequence Data , Plasmids , Recombinant Proteins/genetics
14.
Water Res ; 35(17): 4159-65, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11791845

ABSTRACT

The adsorption isotherms of yellow and red dye solutions onto granular activated carbon at varying solution pHs (2-8). temperatures (15-50 degrees C), and alcohol concentrations (0-20%) were experimentally determined by batch tests and the Tóth model was found to best fit the adsorption isotherm data for varying solution pHs. temperatures, and alcohol concentrations. The maximum adsorption capacity was found to decrease with increasing solution pH and alcohol concentration and could be predicted by the correlation equations obtained in this study. A correlation equation was also obtained to account for the effects of solution temperature on the adsorption equilibrium constant. The 25 degrees C water was found to be a very poor regenerant for the carbon bed presaturated with the yellow dye compared with 20% alcohol solution. A simple equation was derived, based on non-linear wave propagation theory, to predict the desorption curves of activated carbon bed. Given presaturation concentration, bed density and void fraction, and adsorption isotherm, the wave propagation theory predicted the desorption curves quite satisfactorily.


Subject(s)
Coloring Agents/chemistry , Water Purification/methods , Adsorption , Alcohols/chemistry , Charcoal/chemistry , Hydrogen-Ion Concentration , Models, Chemical , Temperature
15.
Chin J Physiol ; 44(3): 143-50, 2001 Sep 30.
Article in English | MEDLINE | ID: mdl-11767286

ABSTRACT

The electromechanical effects of 3-[[4-(2-methoxy phenyl)piperazin-1-yl]methyl]-5-(methylthio)-2,3-dihydroimidazo[1,2-c]quinazoline (DL-017), a newly synthesized quinazoline-derived antihypertensive agent, on mammalian cardiac tissues were evaluated. In driven canine Purkinje fibers, DL-017 decreased twitch tension, the maximal rate of upstroke of the action potential (Vmax), and intracellular Na+ activity (a(i)Na) in a concentration-dependent manner. The action potential duration was decreased in canine Purkinje fibers but increased in guinea pig papillary muscles. In guinea pig ventricular papillary muscles, phenylephrine in the presence of 1 microM propranolol increased the twitch tension in a concentration-dependent manner. At 10 microM, phenylephrine significantly decreased a(i)Na and shortened the action potential duration. DL-017 at 0.01 microM inhibited these phenylephrine-induced effects and shifted the concentration-dependent curve to the right. In sinoatrial nodes, DL-017 inhibited pacemaker activity, involving decreases in the slope of diastolic depolarization and Vmax and an increase in a delay of repolarization. These results suggest that, in addition to blockade of alpha1-adrenoceptors and Na+ channels, DL-017 reduces cardiac excitability and contractility in association with inhibition of slow inward Ca2+ and outward K+ channels. Since two order higher concentrations are required, the contribution of DL-017 to cardiac depressant from blockade of ionic channels seems to be less important when this compound is clinically used as an antihypertensive drug.


Subject(s)
Adrenergic alpha-1 Receptor Antagonists , Adrenergic alpha-Antagonists/pharmacology , Anti-Arrhythmia Agents/pharmacology , Antihypertensive Agents/pharmacology , Quinazolines/pharmacology , Action Potentials/drug effects , Animals , Biological Clocks/drug effects , Dogs , Dose-Response Relationship, Drug , Drug Evaluation , Female , Guinea Pigs , Heart Ventricles/drug effects , Male , Models, Animal , Papillary Muscles/drug effects , Purkinje Fibers/drug effects , Sinoatrial Node/drug effects , Sinoatrial Node/physiology
16.
Opt Lett ; 26(8): 536-8, 2001 Apr 15.
Article in English | MEDLINE | ID: mdl-18040377

ABSTRACT

Self-induced pulsations that are associated with atomic interference have been found in a laser-diode-pumped LiNdP(4)O(12) microchip laser with an intracavity KTP frequency-doubling crystal operating in a ? scheme. The instability and peculiar pulsations that were observed have been verified by a linear stability analysis and numerical simulation of two-mode laser equations, including nonlinear absorptions of a purely quantum nature and spontaneous-emission noise.

17.
Opt Lett ; 26(14): 1060-2, 2001 Jul 15.
Article in English | MEDLINE | ID: mdl-18049519

ABSTRACT

Dynamical instability, chaotic pulsations, and generalized bistability have been observed in a laser-diode-pumped microchip Nd:YAG laser operating in a double transition scheme in which lasing occurs on two transitions with overlapping gain profiles, F(3/2)(4)(2)? I(11/2)(4)(3) and F(3/2)(4)(1)? I(11/2)(4)(2), and simultaneously involves excited Nd atoms from different sublevels of the upper manifold. The modeling of the experimental results requires rate equations that include cross-gain coupling among oscillating modes that belong to different transitions whose population inversion densities are determined by the Boltzmann distribution.

18.
Cell ; 103(2): 331-42, 2000 Oct 13.
Article in English | MEDLINE | ID: mdl-11057905

ABSTRACT

The Drosophila eye disc is a sac of single layer epithelium with two opposing sides, the peripodial membrane (PM) and the disc proper (DP). Retinal morphogenesis is organized by Notch signaling at the dorsoventral (DV) boundary in the DP. Functions of the PM in coordinating growth and patterning of the DP are unknown. We show that the secreted proteins, Hedgehog, Wingless, and Decapentaplegic, are expressed in the PM, yet they control DP expression of Notch ligands, Delta and Serrate. Peripodial clones expressing Hedgehog induce Serrate in the DP while loss of peripodial Hedgehog disrupts disc growth. Furthermore, PM cells extend cellular processes to the DP. Therefore, peripodial signaling is critical for eye pattern formation and may be mediated by peripodial processes.


Subject(s)
Body Patterning , Drosophila Proteins , Drosophila/embryology , Embryonic Induction , Eye/embryology , Transcription Factors , Animals , Calcium-Binding Proteins , Gene Expression Regulation, Developmental , Head/embryology , Hedgehog Proteins , Insect Proteins/metabolism , Intercellular Signaling Peptides and Proteins , Jagged-1 Protein , Larva , Membrane Proteins/metabolism , Nuclear Proteins/metabolism , Phosphoproteins/metabolism , Photoreceptor Cells, Invertebrate/embryology , Proto-Oncogene Proteins/metabolism , Serrate-Jagged Proteins , Wnt1 Protein
19.
J Med Syst ; 24(3): 159-72, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10984870

ABSTRACT

In a longitudinal panel study design, 80 hospitals in Virginia were selected for analysis to test the hypothesis that the introduction of the prospective payment system (PPS) in October 1983 had helped hospitals enhance their operational performance in technical efficiency. A non-parametric method called Data Envelopment Analysis (DEA) was used to calculate and compare the efficiency scores for each peer group of hospitals (by bed size) between the year 1984 and the year 1993. Contrary to expectations, no significant difference in technical efficiency was found in each hospital peer group over the study period. Nevertheless, the case study demonstrates that if hospital managers use this analytical tool appropriately, they may spot where any organizational weakness lies and how they can improve it.


Subject(s)
Economics, Hospital , Efficiency, Organizational , Hospital Administration , Prospective Payment System , Ambulatory Care/economics , Ambulatory Care/organization & administration , Diagnosis-Related Groups/economics , Diagnosis-Related Groups/organization & administration , Hospital Bed Capacity , Hospital Costs , Humans , Longitudinal Studies , Patient Discharge/economics , Personnel, Hospital/economics , Process Assessment, Health Care/economics , Process Assessment, Health Care/organization & administration , Regression Analysis , Statistics, Nonparametric , Virginia
20.
Gen Pharmacol ; 34(1): 25-31, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10793265

ABSTRACT

The pharmacological characterization of EK112, a new combined angiotensin II and thromboxane A(2) receptor blocking agent, was examined in this study. EK112 was found to be a angiotensin II receptor antagonist, as revealed by its competitive antagonism of angiotensin II-induced smooth muscle contraction (pA(2) value of 7. 63 +/- 0.14) in rabbit aorta. It also had an angiotensin II blocking action in guinea pig ileum (pA(2) value of 7.87 +/- 0.67). Additionally, EK112 also possessed thromboxane A(2) receptor blocking activity, since it competitively antagonized aortic contractile responses elicited by U46619 and PGF(2alpha)(pK(B) values of 6.67 +/- 0.09 and 6.24 +/- 0.09, respectively) in rat. In contrast, EK112 did not affect the contractile responses to many other receptor agonists. EK112 did not mimic that of the angiotensin-converting enzyme (ACE) inhibitor, captopril, to enhance the muscle contraction elicited by bradykinin in guinea pig ileum, suggesting that EK112 did not inhibit ACE. Neither cyclic AMP nor cyclic GMP content in rat aortic rings was changed by EK112. These data demonstrate that EK112 is a selective antagonist of angiotensin II > thromboxane A(2) thromboxane A(2) receptor.


Subject(s)
Angiotensin II/antagonists & inhibitors , Receptors, Thromboxane/antagonists & inhibitors , Vasoconstrictor Agents/antagonists & inhibitors , Angiotensin II/pharmacology , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Aorta/drug effects , Aorta/physiology , Captopril/pharmacology , Male , Rabbits , Rats , Rats, Wistar , Vasoconstriction/drug effects , Vasoconstriction/physiology , Vasoconstrictor Agents/pharmacology
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