Scopus 1991-2000
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Publication Metadata only Quinolones and multidrug-resistant tuberculosis(1999-08-06) Khun Nanta Maranetra; Mahidol University; Faculty of Medicine, Siriraj Hospital, Mahidol UniversityThe prevalence of initial resistance of multidrug-resistant tuberculosis (MDR-TB) to at least isoniazid (INH) and rifampicin (RFP) in Thailand during the period 1993-1997 is reported; in this era, trends for INH + RFP + streptomycin (SM) and ethambutol (EMB), INH + RFP + SM or EMB and MDR-TB were stable. The prevalence of acquired MDR-TB is on a slight downward trend, with the latest level at 22.6%. Recommended management of MDR-TB is outlined and advantages and disadvantages of these guidelines discussed. The role of ofloxacin in MDR-TB is presented, with results from a study performed by the Thailand CDC showing that the percentage of strains resistant to ofloxacin was 4.3%, and to ciprofloxacin was 8.3%. The resistance to both ofloxacin and ciprofloxacin was very low at 1.4%. The percentage of cross-resistance between these fluoroquinolones was also low; 33% resistant to ofloxacin were also resistant to ciprofloxacin and only 17% of those resistant to ciprofloxacin were also resistant to ofloxacin. Results from a clinical trial evaluating ofloxacin with other drugs for MDR-TB are also reported. The regimen comprised ofloxacin 600 mg/day, pyrazinamide (PZA), two to three months of kanamycin (KM) or amikacin (AMK), para-aminosalicylic acid (PAS) plus EMB or thiacetazone. Drugs were given for 18 months. Follow-up was every three months for two years. Preliminary results revealed that the percentage of acquired MDR-TB resistant to specific agents was as follows: 36% resistant to INH and RFP, 23% resistant to INH, RFP plus EMB, 27% resistant to INH, RFP and SM, and 14% resistant to all four of these agents (INH + RFP + SM + EMB). All isolates were sensitive to ofloxacin. At one month of treatment, sputum culture conversion was approximately 25%, climbing to 93% by nine months of treatment. Treatment with ofloxacin in a combined regimen achieved a success rate of 78%. The role of quinolones in preventing TB in MDR-TB contacts is also discussed.Publication Metadata only Influence of hemoglobin E trait on the antimalarial effect of artemisinin derivatives(2000-05-22) Robert Hutagalung; Polrat Wilairatana; Sornchai Looareesuwan; Gary M. Brittenham; Victor R. Gordeuk; Mahidol University; Columbia University, College of Physicians and Surgeons; Center for Sickle Cell Disease - DCTo determine whether hemoglobin E trait influences the antimalarial effect of artemisinin derivatives, we retrospectively compared 32 case patients with hemoglobin E trait to 32 control patients who did not have hemoglobin E, β-thalassemia, glucose-6-phosphate dehydrogenase deficiency, or α-thalassemia trait on the basis of a mean corpuscular volume ≥78 femtoliters. All patients were admitted to the Hospital for Tropical Diseases in Bangkok, Thailand, with acute falciparum malaria. Control patients were matched to case patients with hemoglobin E trait by treatment with artemisinin derivatives versus other antimalarial drugs, by ethnic group, and by parasite count. Among 38 patients treated with artemisinin derivatives, the presence of hemoglobin E trait was associated with significantly faster parasite clearance (2.9-fold; 95% confidence interval [CI], 1.4-6.3; P = .006). Among 26 patients treated only with other antimalarial drugs, hemoglobin E trait did not significantly enhance parasite clearance (hazards ratio, 1.1; 95% CI, 0.5-2.5; P = .8). Hemoglobin E trait may potentiate the antimalarial effect of artemisinin derivatives.Publication Metadata only Prognostic significance of skin and subcutaneous fat sequestration of parasites in severe falciparum malaria(2000-06-01) Polrat Wilairatana; Mario Riganti; Pranom Puchadapirom; Benjanee Punpoowong; Suparp Vannaphan; Rachanee Udomsangpetch; Srivicha Krudsood; Gary M. Brittenham; Sornchai Looareesuwan; Mahidol University; MetroHealth Medical Center ClevelandIntradermal blood smear, histopathologic and immunohistologic studies were performed in severe malaria (n=10) and uncomplicated malaria (n=10) patients during positive parasitemia and within 6 hours after negative parasitemia by finger prick smears. Intradermal blood smears showed asexual forms and intraleukocytic pigments when finger prick blood smears showed negative results; however intradermal blood smear did not indicate disease severity within 6 hours after negative parasitemia by finger prick. Histopathologic findings showed 15 fold higher parasitized red blood cells sequestered in vessels of subcutaneous fatty tissue in severe malaria than in uncomplicated malaria (p<0.001) and may indicate disease severity. A panel of polyclonal antibodies against cytokines applied to skin biopsies clearly detected a higher titer against tumor necrosis factor-alpha (TNFα) and interleukin-10 (IL-10) in dermal vessels and stratum granulosum respectively, in severe malaria compared with uncomplicated malaria. Results of the study suggest that histopathology and immunohistology of skin and subcutaneous fatty tissue may indicate prognostic severity of malaria and may be associated with focal accumulation of cytokines.Publication Metadata only Parvovirus B19 caused fetal death : A case report in Thailand(2000-12-01) Prachumporn Booncharoen; Yaowalug Boonpasat; Siriporn Sriurairatana; Mahidol UniversityThis was a case of an intrauterine parvoviral B19 infection resulting in hydrops fetalis and enlarged placenta. Histologically, the virus was found to be in nucleated red cells of the fetus which was confirmed by electron microscopy. Careful placental examination at the gross and microscopic levels yielded the correct diagnosis.Publication Metadata only A case-control auditory evaluation of patients treated with artemisinin derivatives for multidrug-resistant Plasmodium falciparum malaria(2000-01-01) M. Van Vugt; B. J. Angus; R. N. Price; C. Mann; J. A. Simpson; C. Poletto; Saw Eh Htoo; S. Looareesuwan; N. J. White; F. Nosten; Shoklo Malaria Research Unit; Academic Medical Centre, University of Amsterdam; Mahidol University; John Radcliffe Hospital; Southern General Hospital Glasgow; Charing Cross HospitalThe artemisinin derivatives are now used widely in areas with multidrug- resistant Plasmodium falciparum malaria such as Southeast Asia, but concerns remain over their potential for neurotoxicity. Mice, rats, dogs, and monkeys treated with high doses of intramuscular artemether or arteether develop an unusual pattern of focal damage to brain stem nuclei (particularly those involved in auditory processing). To investigate whether a similar toxic effect occurs in patients treated with these compounds, clinical neurologic evaluation, audiometry and early latency auditory evoked responses were measured in a single-blind comparison of 79 patients who had been treated with ≥2 courses of oral artemether or artesunate within the previous 3 years, and 79 age- and sex-matched controls living in a malaria-endemic area on the northwestern border of Thailand. There were no consistent differences in any of these test results between the cases and controls. This study failed to detect any evidence of significant neurotoxicity in patients treated previously with oral artemether or artesunate for acute malaria.Publication Metadata only In vitro sensitivity of Plasmodium falciparum and clinical response to lumefantrine (benflumetol) and artemether(2000-05-10) Peerapan Tanariya; Pongsri Tippawangkoso; Juntra Karbwang; Kesara Na-Bangchang; Walther H. Wernsdorfer; Mahidol University; Universitat WienAims. To assess the sensitivity of 103 Plasmodium falciparum isolates to a combination of lumefantrine (benflumetol) and artemether (CGP 56697), with the objective of determining a correlation between in vitro drug sensitivity and therapeutic outcome. Methods. Patients suffered from uncomplicated falciparum malaria and came from areas of Thailand affected by multidrug resistance. CGP 56697 was given in the form of tablets containing 20 mg artemether and 120 mg lumefantrine. The standard dose regimen, 4 doses of 4 tablets over 48 h, was compared with two lower dose regimens (4 x 2 tablets and 3 x 4 tablets). Results. The parasites showed high resistance to chloroquine, fairly advanced resistance to mefloquine and compromised sensitivity to quinine. Sensitivity to artemisinin and lumefantrine prior to treatment was similar in all treatment groups. The 4 x 4 tablet regimen was more effective than the other regimens in coping with infections with relatively low sensitivity to artemisinin and/or lumefantrine. The EC 90 for artemisinin is an important determinant of treatment success. Parasite density at the start of treatment was identified as another critical predictor of treatment outcome. Conclusions. The results indicate that parasite exposure to the drugs may have been inadequate and/or too short in the cases of treatment failure, particularly marked in the lower dose regimens. This could probably be remedied by expanding the dose regimen in areas affected by multidrug resistance and in the case of relatively high parasitaemia.Publication Metadata only Accuracy of Orbscan total optical power maps in detecting refractive change after myopic laser in situ keratomileusis(1999-12-01) Sabong Srivannaboon; Dan Z. Reinstein; Hugo F S Sutton; Simon P. Holland; The University of British Columbia; Weill Cornell Medical College; Mahidol UniversityPurpose: To determine whether the refractive change obtained using the Orbscan-derived total optical power (TOP) map is in concordance with the manifest refractive change produced by laser in situ keratomileusis (LASIK). Setting: LASIK Vision Canada, Vancouver, BC, Canada (an ambulatory surgical center for refractive surgery). Methods: Twenty eyes of 10 consecutive bilateral LASIK patients were included in the study. Orbscan topographical analysis and manifest refraction were performed preoperatively and at least 1 month postoperatively. The change in manifest refraction (corrected to the corneal plane) before and after LASIK was correlated with the corneal power change averaged within the 2.0, 3.0, 4.0, and 5.0 mm diameter zones of TOP and axial power maps. Results: The central 4.0 mm zone TOP map gave the best correlation between manifest refractive change and Orbscan-measured corneal power change (r2= 0.835, P < .004). The correlation was higher with TOP maps than with anterior axial power maps. Conclusion: The corneal power change measured by the Orbscan TOP maps correlated highly with the changes in manifest refraction after LASIK.Publication Metadata only Erratum: Pharmacokinetic-pharmacodynamic evaluation of ceftazidime continuous infusion vs intermittent bolus injection in septicaemic melioidosis (British Journal of Clinical Pharmacology (2000) 49 (445-452))(2000-01-01) B. J. Angus; M. D. Smith; Y. Suputtamongkol; H. Mattie; A. L. Walsh; V. Wuthiekanun; W. Chaowagul; N. J. White; Mahidol University; Leiden University Medical Center - LUMC; Sappasitthiprasong HospitalAims. Experimental studies have suggested that constant intravenous infusion would be preferable to conventional intermittent bolus administration of beta-lactam antibiotics for serious Gram-negative infections. Severe melioidosis (Burkholderia pseudomallei infection) carries a mortality over 40% despite treatment with high dose ceftazidime. The aim of this study was to measure the pharmacokinetic and pharmacodynamic effects of continuous infusion of ceftazidime vs intermittent bolus dosing in septicaemic melioidosis. Methods. Patients with suspected septicaemic melioidosis were randomised to receive ceftazidime 40 mg kg-18 hourly by bolus injection or 4 mg kg-1h-1by constant infusion following a 12 mg kg-1priming dose and pharmacokinetic and pharmacodynamic parameters were compared. Results. Of the 34 patients studied 16 (59%) died. Twenty patients had cultures positive for B. pseudomallei of whom 12 (60%) died. The median MIC90of B. pseudomallei was 2 mg l-1, giving a minimum target concentration (4*MIC) of 8 mg l-1. The median (range) estimated total apparent volume of distribution, systemic clearance and terminal elimination half-lives of ceftazidime were 0.468 (0.241-0.573) l kg-1, 0.058 (0.005-0.159) l kg-1h-1and 7.74 (1.95-44.71) h, respectively. Clearance of ceftazidime and creatinine clearance were correlated closely (r = 0.71; P < 0.001) and there was no evidence of significant nonrenal clearance. Conclusions. Simulations based on these data and the ceftazidime sensitivity of the B. pseudomallei isolates indicated that administration by constant infusion would allow significant dose reduction and cost saving. With conventional 8 h intermittent dosing to patients with normal renal function, plasma ceftazidime concentrations could fall below the target concentration but this would be unlikely with a constant infusion. Correction for renal failure, which is common in patients with meliodosis is Clearance = k* creatinine clearance where k = 0.72. Calculation of a loading dose gives median (range) values of loading dose, D(L) of 18.7 mg kg-1(9.5-23) and infusion rate I = 3.5 mg kg-1h-1(0.4-13) (which equals 84 mg kg-1day-1). A nomogram for adjustment in renal failure is given.Publication Metadata only Lethal toxicity of Vibrio harveyi to cultivated Penaeus monodon induced by a bacteriophage(1999-02-26) Lila Ruangpan; Yaowanit Danayadol; Sataporn Direkbusarakom; Siriporn Siurairatana; T. W. Flegel; Thailand National Institute of Coastal Aquaculture; Mahidol UniversityIn Southern Thailand in 1996, intense luminescence in many shrimp rearing ponds was accompanied by massive mortality resulting in total crop loss within 3 or 4 d. Mortality was correlated with gross signs which shrimp farmers called (English translation) tea-brown gill syndrome (TBGS). Histological examination of moribund shrimp revealed massive lesions of the hepatopancreas characterized by hemocytic infiltration and the presence of bacterial cells. Bacterial isolation yielded several strains tentatively identified as Vibrio harveyi on the basis of luminescence and growth on BTB Teepol agar. Representative isolate VH1039 was selected and identified by biochemical tests as V. harveyi. When strain VH1039 and the other luminescent isolates were injected into normal shrimp (1 x 107cells shrimp-1), no significant mortality was observed in comparison with control shrimp injected without bacteria. Nor was any significant mortality observed after injection of supernatant fluids from normal or sonicated bacterial cultures of VH1039 (1 x 108cells ml-1). Transmission electron microscopy (TEM) of hepatopancreatic tissue from farmed TBGS shrimp revealed bacterial cells of Vibrio morphology together with large numbers of bacteriophage particles that had round to hexagonal heads of approximately 60 nm diameter and tails of approximately 100 nm length. These were either free, attached to cell walls of intact bacteria or in various stages of replication within bacterial cells. Gills of farmed TBGS shrimp were subsequently homogenized in lobster haemolymph buffer (LHB) and membrane filtered (0.22 μm). Compared to control shrimp injected with LHB, shrimp injected with the 1000x diluted gill filtrate (DGF) showed no significant mortality. However, when DGF was injected together with 1 x 107cells of strain VH1039, there was total mortality within 48 h. High and rapid mortality concurrent with brown gills was seen only in the mixed injection group. TEM of the artificially infected shrimp tissues did show the presence of bacterial cells, but no mature bacteriophage particles or lysed bacterial cells were found similar to those seen in farmed TBGS shrimp. In further tests, addition of DGF to cultures of VH1039 induced extreme but transitory toxicity of culture filtrates from 24 to 36 h. Treatment of DGF with a germicidal lamp (UV) for 30 min or with heat at 100°C for 15 min failed to stop shrimp mortality from mixed DGF/VH1039 injections. However, mortality was stopped if the heated DGF was treated with DNase. The results suggested that a bacteriophage may sometimes mediate the toxicity of V. harveyi in Penaeus monodon by the transfer of a toxin gene(s) or a gene(s) controlling toxin production.Publication Metadata only Chroman amide 12P inhibition of lipid peroxidation and protection against learning and memory impairment(2000-08-25) Opa Vajragupta; Orawan Monthakantirat; Yuvadee Wongkrajang; Hiroshi Watanabe; Penchom Peungvicha; Mahidol University; University of ToyamaStructure modification of the cerebroprotective chroman amide 12 to improve the drug delivery to the target organ by protecting the active hydroxy functional group was carried out in this study. Chroman amide 12P, which the O-acetyl group was served to protect the active group to be delivered to the target organ, was synthesized. Ex vivo antilipid peroxidation activity of 12P was significantly greater than the activity of 12 while the in vitro inhibition of 12P was found to be lower. These indicated that 12P with protected active group effectively reached the brain, the target site, but in vitro, 12P was unable to release its parent or released slowly. Neuropharmacological effect of 12P was investigated in mice. 12 and 12P (50-100 mg/kg, i.p.) showed significant suppression on the hypermotility induced by methamphetamine. 12P (100 mg/kg, i.p.) was more potent than 12, 54.36% and 38.73% suppression, respectively. The result suggested the enhancement of brain delivery and the antagonism against aberrant dopamine release. In the water maze test, 12P (200 mg/kg) as well as tacrine (3 mg/kg) significantly reduced the learning and memory impairment induced by scopolamine (0.5 mg/kg). The results support the enhanced brain delivery and the additional role of radical scavengers in the modulation of brain neurotransmitters in the aberrant condition. (C) 2000 Elsevier Science Inc.Publication Metadata only Recombinant activated factor VII in children with acute bleeding resulting from liver failure and disseminated intravascular coagulation(2000-01-01) Ampaiwan Chuansumrit; T. Chantarojanasiri; P. Isarangkura; S. Teeraratkul; S. Hongeng; P. Hathirat; Mahidol UniversityRecombinant activated factor VII (rFVIIa) was given to three children with acute bleeding resulting from liver failure and disseminated intravascular coagulation. Cases I and II (girls aged 3 years and 6 years, respectively) were diagnosed with Dengue hemorrhagic fever and prolonged shock. Case III, a boy aged 9 months, underwent left lobe hepatectomy for a hepatoblastoma, during which 60% of his liver was removed. This case was complicated by myoglobinuria, liver and renal impairment and early disseminated intravascular coagulation. All three patients exhibited active bleeding. Cases I and II received rFVIIa combined with other blood component replacement, while Case III received rFVIIa as the only hemostatic agent. A bolus of 40-180 μg/kg b.w. was administered followed by 16.533 μg/kg b.w. per h continuous infusion. As a result, bleeding was controlled, the prothrombin time was shortened and FVII clotting activity was significantly increased. In conclusion, rFVIIa has shown some efficacy in controlling acute bleeding in children with liver failure and disseminated intravascular coagulation. (C) 2000 Lippincott Williams and Wilkins.Publication Metadata only Partial purification and characterization of mitochondrial DNA polymerase from Plasmodium falciparum(2000-11-23) Porntip Chavalitshewinkoon-Petmitr; Srisucha Chawprom; Lieve Naesens; Jan Balzarini; Prapon Wilairat; Mahidol University; KU LeuvenMitochondria of chloroquine-resistant Plasmodium falciparum (K1 strain) were isolated from mature trophozoites by differential centrifugation. The mitochondrial marker enzyme cytochrome c reductase was employed to monitor the steps of mitochondria isolation. Partial purification of DNA polymerase from P. falciparum mitochondria was performed using fast protein liquid chromatography (FPLC). DNA polymerase of P. falciparum mitochondria was characterized as a γ-like DNA polymerase based on its sensitivity to the inhibitors aphidicolin, N-ethylmaleimide and 9-β-D-arabinofuranosyladenine-5'-triphosphate. In contrast, the enzyme was found to be strongly resistant to 2',3'-dideoxythymidine-5'-triphosphate (IC50> 400 μM) and differed in this aspect from the human homologue, possibly indicating structural differences between human and P. falciparum DNA polymerase γ. In addition, the DNA polymerase of parasite mitochondria was shown to be resistant (IC50> 1 mM) to the nucleotide analogue (S)-1-[3-hydroxy-2-phosphonylmethoxypropyl]adenine diphosphate (HPMPApp). (C) 2000 Elsevier Science Ireland Ltd.Publication Metadata only The mechanisms of parasite clearance after antimalarial treatment of Plasmodium falciparum malaria(2000-01-01) K. Chotivanich; R. Udomsangpetch; A. Dondorp; T. Williams; B. Angus; J. A. Simpson; S. Pukrittayakamee; S. Looareesuwan; C. I. Newbold; N. J. White; Mahidol University; Academic Medical Centre, University of Amsterdam; Weatherall Institute of Molecular Medicine; Nuffield Department of Clinical MedicineStudies were conducted to determine how malaria parasites are cleared from the blood after antimalarial treatment. Neither artesunate nor quinine decreased parasitized red cell deformability or increased antibody binding. In acute falciparum malaria, ring-infected erythrocyte surface antigen (RESA) was observed in erythrocytes without malaria parasites (RESA-red blood cell [RBC]), indicating prior parasitization. In uncomplicated malaria, RESA-RBC numbers increased significantly (P = .002) within 24 h of starting artesunate but rose much more slowly (7 days) after quinine treatment. In severe malaria, RESA-RBC increased significantly (P = .001) within hours of starting artesunate but not with quinine treatment (P = .43). RESA-RBCs were not produced after drug treatment of malaria parasite cultures in vitro. Rapid malaria parasite clearance after treatment with artemisinin derivatives results mainly from the extraction of drug-affected parasites from host erythrocytes - presumably by the spleen. This explains why the fall in hematocrit after treatment of hyperparasitemia is often less than that predicted from loss of parasitized cells.Publication Metadata only Neurological dysfunction following malaria: Disease- or drug-related? [1](2000-01-01) N. J. White; Mahidol UniversityPublication Metadata only Interactions of Penicillium marnefrei with human leukocytes in vitro(1999-01-01) Yong Rongrungruang; Stuart M. Levitz; Mahidol University; Boston Medical Center; Boston University School of MedicinePenicillium marneffei, a dimorphic fungus endemic in parts of Asia, causes disease in those with impaired cell-mediated immunity, especially persons with AIDS. The histopathology of penicilliosis marneffei features the intracellular infection of macrophages. We studied the interactions between human leukocytes and heat-killed yeast-phase P. marneffei. Monocyte-derived macrophages bound and internalized P. marneffei in the presence of complement-sufficient pooled human serum (PHS). Binding and phagocytosis were still seen if PHS was heat inactivated or omitted altogether. The binding of unopsonized P. marneffei to monocyte-derived macrophages occurred in the absence of divalent cations and was not affected by inhibitors of mannose and β-glucan receptors or monoclonal antibodies directed against CD14 and CD11/CD18. Binding was profoundly inhibited by wheat germ agglutinin. A vigorous respiratory burst was seen in peripheral blood mononuclear cells (PBMC) stimulated with P. marneffei, regardless of whether the fungi were opsonized. However, tumor necrosis factor alpha (TNF-α) release from PBMC stimulated with P. marneffei occurred only if serum was present. These data demonstrate that (i) monocyte-derived macrophages bind and phagocytose P. marneffei even in the absence of opsonization, (ii) binding is divalent cation independent but is inhibited by wheat germ agglutinin, suggesting that the major receptor(s) recognizing P. marneffei is a glycoprotein with exposed N-acetyl-β-D-glucosaminyl groups, (iii) P. marneffei stimulates the respiratory burst regardless of whether opsonins are present, and (iv) serum factors are required for P. marneffrei to stimulate TNF-α release. The ability of unopsonized P. marneffei to parasitize mononuclear phagocytes without stimulating the production of TNF-α may be critical for the virulence of this intracellular parasite.Publication Metadata only Early complications of gastric transposition operation(2000-12-01) Ravit Ruangtrakool; M. D. Lewis Spitz; Mahidol UniversityGastric transposition was performed in 100 children as a definitive procedure for oesophageal replacement between 1982 and 1997 for 69 oesophageal atresia (41 with distal tracheooesophageal fistula, 20 isolated oesophageal atresia and 8 with proximal tracheooesophageal fistula), 16 severe caustic stricture, 7 intractable peptic reflux stricture and 8 miscellaneous causes. Six mortalities were recorded. Sixty-five patients had complications postoperatively and respiratory complication was the most common complication especially in oesophageal atresia patients. Swallowing difficulty, particularly in oesophageal atresia, occurred in 21 per cent of the patients. Ten patients developed cervical leakage with spontaneous closure and 8 patients suffered from anastomosis stricture. Six jejunostomy revisions were required. Three of five pyloromyotomy obtained inadequate gastric drainage post gastric transposition and required the conversion to pyloroplasty. Because of the distinctive low major life-threatening morbidity and low mortality, we concluded that gastric transposition was a safe, easy and preferable procedure for oesophageal replacement in children.Publication Metadata only Effects of sulphapyridine on sperm transport through the rat epididymis and contractility of the epididymal duct(1999-01-01) G. Chaturapanich; K. Sujarit; C. Pholpramool; Mahidol UniversityThis study was undertaken to investigate the effects of sulphapyridine on the transport of spermatozoa through different regions of the epididymis and on the contractility of the epididymal duct in the rat. Sperm transport was investigated by labelling testicular spermatozoa with [3H]thymidine and measuring intraluminal pressures of the epididymis by micropuncture, using a servo-nulling pressure transducer system. In control rats, the transit times of epididymal spermatozoa from the initial segment to the caput, from the caput to the proximal cauda, and from the proximal cauda to the distal cauda were 2, 6 and 3 days, respectively, giving a total transit time of 11 days. The total transit time was shortened to 8 days after treatment with sulphapyridine at a dosage of 450 mg kg-1for 38-52 days. The rate of sperm transport was most affected in the caput epididymidis. Measurements of intraluminal pressures showed that sulphapyridine had no effect on spontaneous contractions in any regions of the epididymis. However, the frequency of contraction of the corpus and cauda epididymides in response to administration of 10 μg noradrenaline kg-1in the sulphapyridine-treated rats was significantly higher (P < 0.05) than it was in the controls. Methacholine, at a dose of 20 μg kg-1, produced a smaller increase in basal pressure in the caput epididymidis of sulphapyridine-treated rats (P < 0.05) compared with controls. The results led to the conclusion that sulphapyridine increases the rate of sperm transport from the caput through the cauda epididymidis, in part, by changes in the responsiveness of the epididymis to the autonomic nervous system.Publication Metadata only Cost-effectiveness of IVF in women 38 years and older(2000-05-01) C. Suchartwatnachai; A. Wongkularb; C. Srisombut; W. Choktanasiri; S. Chinsomboon; A. Rojanasakul; Mahidol UniversityObjective: To compare the cost per delivery in women younger than 38 years with women equal to or older than 38 years of age attempting IVF. Methods: All couples undergoing IVF treatment between October 1991 and September 1998 were enrolled in this study. A standard protocol of controlled ovarian hyperstimulation was employed throughout the study. Four hundred and seven cases were allocated to two groups - group I composed of patients younger than 38 years of age and group II of patient equal to or older than 38 years of age. The total cost of each successful outcome was the goal of our study. Results: A total of 407 women underwent 722 stimulated cycles for IVF of which 122 cycles (16.89%) did not proceed to oocyte retrieval. We found statistically significant differences in the cancellation rate, the number of hMG ampoules, the number of oocytes retrieved, the number of oocytes fertilized, the number of embryos transferred, the clinical pregnancy rate, the rate of multiple pregnancy, the delivery per initiated cycle and the cost per delivery between the two groups (P<0.05, significant). The cost per delivery in group II was approximately 3.6 times that of group I. Conclusions: Women age 38 years or more have less chance of a successful outcome from IVF treatment. Couples contemplating IVF should be provided with accurate information about prognosis for the pregnancy and the financial costs. Copyright (C) 2000 International Federation of Gynecology and Obstetrics.Publication Metadata only Protein polymorphism in natural populations of Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in Thailand(1999-11-06) Sangvorn Kitthawee; Duangta Julsilikul; Rosie G. Sharpe; Visut Baimai; Mahidol University; University of LeedsDiachasmimorpha longicaudata (Ashmead) is a larval parasitoid of tephritid flies and is widely used as a classical biological control agent. We have used allozyme electrophoresis to evaluate the genetic relationships of six populations of D. longicaudata in Thailand. Twelve loci were examined of which 11 were polymorphic in at least some populations, especially that of Nakornratchasima. We observed a complete lack of heterozygotes for seven of the 10 polymorphic loci in the Nakornratchisima female population, and a significant deficiency of heterozygotes at a further two loci. We discuss possible hypotheses for these findings in light of the haplo-diploid sex determination system of these wasps.Publication Metadata only Malaria in tree crop plantations in south-eastern and western provinces of Thailand(1999-09-01) Pratap Singhasivanon; Krongthong Thimasarn; Surapon Yimsamran; Kenneth Linthicum; Kaew Nualchawee; Darasri Dawreang; Suthep Kongrod; Nilarat Premmanisakul; Wanchai Maneeboonyang; Nelia Salazar; Mahidol University; Thailand Ministry of Public Health; Armed Forces Research Institute of Medical Sciences, Thailand; Asian Institute of Technology Thailand; SEAMEO-TROPMED NetworkDuring the past three decades almost half of the existing natural tropical forests in Thailand were destroyed and replaced by cash crops, rubber, coffee, fruit orchards (durian, rambutan, mangosteen) and other commercial plantations. In order to determine the proportion of malaria cases contracted from such commercial plantations, an epidemiological study was conducted between June 1996 to May 1997 in two districts, one in Pong Nam Ron, located in a south-eastern province near the Cambodian border and another in Sai Yok, in a western province along the Myanmar border. Data were collected by passive case detection from patients attending the existing malaria clinics and active case detection by monthly malariometric survey in selected villages. All malaria cases were thoroughly investigated and classified according to exposure to different ecotypes prior to onset of malaria symptoms in the preceding two weeks. Malaria cases acquired from commercial plantations accounted for 35.2% and 11.2% in Pong Nam Ron and in Sai Yok districts respectively. In such plantations, most of the malaria cases were contracted from fruit orchards and to a lesser extent from rubber and teak plantations. From this study it is evident that commercial plantations provide a significant site of malaria transmission in addition to the forest and foothills areas in Southeast Asia where efficient vectors such as An. dirus and An. minimus are prevalent and have adapted to such changed ecosystems.