Comparative analyses of published cost effectiveness models highlight critical considerations which are useful to inform development of new models.

Background: Comparative analyses of published cost effectiveness models provide useful insights into critical issues to inform the development of new cost effectiveness models in the same disease area.Objective: The purpose of this study was to describe a comparative analysis of cost-effectiveness models and highlight the importance of such work in informing development of new models. This research uses genotypic antiretroviral resistance testing after first line treatment failure for Human Immunodeficiency Virus (HIV) as an example.Method: A literature search was performed, and published cost effectiveness models were selected according to predetermined eligibility criteria. A comprehensive comparative analysis was undertaken for all aspects of the models.Results: Five published models were compared, and several critical issues were identified for consideration when developing a new model. These include the comparator, time horizon and scope of the model. In addition, the composite effect of drug resistance prevalence, antiretroviral therapy efficacy, test performance and the proportion of patients switching to second-line ART potentially have a measurable effect on model results. When considering CD4 count and viral load, dichotomizing patients according to higher cost and lower quality of life (AIDS) versus lower cost and higher quality of life (non-AIDS) status will potentially capture differences between resistance testing and other strategies, which could be confirmed by cross-validation/convergent validation. A quality adjusted life year is an essential outcome which should be explicitly explored in probabilistic sensitivity analysis, where possible.Conclusions: Using an example of GART for HIV, this study demonstrates comparative analysis of previously published cost effectiveness models yields critical information which can be used to inform the structure and specifications of new models.

Semen characteristics and sperm morphology of serow (Capricornis sumatraensis).

The serow (Capricornis sumatraensis) is a critically endangered species. The objectives of this study were to evaluate ejaculate quality in captive males, and to investigate and characterize sperm morphology. Semen was collected using electroejaculation. Mean (+/-S.D.) seminal characteristics were: semen volume 2.3+/-0.8 mL, pH 7.8+/-0.4, and osmolality 329.9+/-32.9mOsmol/kg; sperm concentration 515.8+/-263.1 x 10(6) cells/mL; wave motion score (1-5) 3.9+/-0.4; motile sperm 60.5+/-22%; viable sperm 68.3+/-9.4%; morphologically normal sperm 70.8+/-19.3%; and an opacity that was yellowish to milky-white. Sperm head length, width, degree of elongation, area, and perimeter were 6.0+/-0.6 microm, 4.3+/-0.3 microm, 71.7+/-8.6%, 19.8+/-2.5 microm(2), and 17.9+/-2.1 microm. Based on these measurements, we categorized sperm head morphometry as small, medium, or large. In addition, sperm morphology was examined by light and scanning electron microscopy; overall, morphologically normal and abnormal sperm were similar to those reported for other bovidae. In summary, this study provided baseline data regarding semen characteristics of C. sumatraensis, which should be of value in the preservation of this endangered species.

Biological control of rodents using Sarcocystis singaporensis.

Parasites have been identified as an important factor in regulating vertebrate populations. In replicated field experiments (plots up to 4 ha) performed in Thailand we tested whether commensal and field rodents could be artificially infected and controlled with the host-restricted apicomplexan protozoon Sarcocystis singaporensis which is endemic in Southeast Asia. When bait-pellets containing high numbers of these parasites were consumed by rodents of three species (Rattus norvegicus, Rattus tiomanicus, Bandicota indica) in different agricultural habitats (chicken farm, oil palm plantation, ricefield), we observed a parasite-induced mortality ranging from 58% to 92%. Detection of merozoites of S. singaporensis in lung tissue samples of rats collected dead at the experimental sites using a species-specific monoclonal antibody confirmed that S. singaporensis was the causative agent of mortality. As observed with brown rats, the parasite's effect on the host was not related to sex. These experiments demonstrate for the first time that artificial infection of rodents with an endemic protozoon has the potential for effective population control.

Blood coagulation and platelet profiles in persistent post-splenectomy thrombocytosis. The relationship to thromboembolism.

To clarify the possible role of persistent thrombocytosis after splenectomy being a predisposing factor causing development of thromboembolism, blood coagulation profiles and platelet functions were studied in 34 cases being 1-18 years post-splenectomy from non-malignant diseases. Persistent thrombocytosis was observed in 16 with significant negative correlation between hemoglobin level and platelet count indicated the role of anemia on persistent post-splenectomy thrombocytosis. Blood coagulation profiles showed accelerated thrombin formation or hypercoagulability as measured by thrombin generation test especially in cases with thrombocytosis, together with decreased fibrinolytic activity and high fibrinogen, but in presence of high antithrombin III activity. Concerning the platelet, the aggregation to ristocetin was defective, the improved aggregation to ADP and adrenaline was achieved only in whom with intact spleen giving defective platelet aggregation. The finding indicated the role of spleen contributing to abnormal platelet aggregation. Another interesting observation was the decreased platelet 5-hydroxytryptamine content in splenectomized cases. The overall changes on blood coagulation and platelets post-splenectomy including those with persistent thrombocytosis did not thoroughly shift to hypercoagulable state, since a high antithrombin III activity and some platelet defect remained. These present findings, therefore, unlikely predisposed to the occurrence of thromboembolism even in those with persistent thrombocytosis.

Sarcosporidiasis in rodents from Thailand.

One to six Sarcocystis spp. were identified in the skeletal muscles of 41 (33%) of 124 wild rodents (Rattus spp. and Bandicota indica) mainly captured in the central plains of Thailand throughout the year in 1995. Included were S. singaporensis, S. villivillosi, and S. murinotechis-like cysts all of which showed a striated cyst wall at the light microscopical level, and Sarcocystis cymruensis, S. sulawesiensis, and S. zamani which possessed smooth cyst walls. The ultrastructure of the cyst wall and other morphological characteristics used to distinguish species are described. By inoculation of muscle cysts from wild-caught rodents into coccidia-free pythons (Python reticulatus, P. molurus bivittatus), we confirmed that P. reticulatus is a suitable definitive host for S. singaporensis and S. zamani in Thailand. Furthermore, we showed by fecal examination of reticulated pythons collected in the wild and subsequent experimental infection of laboratory rats that these hosts also are naturally infected with both species. Sarcocystis cymruensis is reported for the first time from Southeast Asia. This parasite was prevalent in brown rats (Rattus norvegicus) and bandicoot rats (B. indica) which were captured near human habitations; it is likely to be transmitted to rats via cats. The definitive hosts of S. sulawesiensis and S. murinotechis are unknown. Hence, at least three Sarcocystis spp. (S. singaporensis, S. zamani, S. villivillosi) are likely to cycle between snakes and rodents in agricultural areas in Thailand. Among these, S. singaporensis appears to be the most prevalent species.

Significance of blood coagulation and platelet profiles in relation to pulmonary thrombosis in beta-thalassemia/Hb E.

In beta-Thalassemia hemoglobin E (beta-thal Hb E), hypoxemia with abnormal lung function was described and postmortem examination in these patients showed organized pulmonary trombi with thickened arterial wall, particularly in post-splenectomized cases. Coagulation and platelet profiles were studied in 58 beta-thal Hb E patients. In 35 cases with intact spleen, the fibrinolytic activity was significantly decreased with high antithrombin III activity, while coagulation tests revealed mild abnormality. The platelet aggregation to ADP, adrenaline, collagen and ristocretin were defective and platelet 5-hydroxytryptamine content was lower than normal. Twenty-three patients who had been splenectomized for 5-18 years, decreased fibrinolytic activity and high antithrombin III activity were also observed. The coagulation profiles and platelet aggregation in response to ADP, adrenaline and collagen showed better results. Fourteen cases exhibited thrombocytosis and their thrombin generation was in the hypercoagulable range. Platelet aggregation in response to ristocetin remained defective and platelet 5-hydroxytryptamine content was lower than in cases with intact spleens. Defective aggregation to ristocetin would indicate abnormal von Willebrand's factor (vWF). Decreased fibrinolysis should very likely have a role in the occurrence of thrombosis and the better hemostatic profiles in post-splenectomized cases would contribute to the more frequent thrombotic incidence in these cases.

Low dose aspirin and its antithrombotic effect in ischaemic stroke patient.

The investigators conducted a study of low dose aspirin and antithrombotic effectiveness in ischaemic strokes at Siriraj hospital Medical School, Mahidol University from July 1986 to June 1987. Thirty-six patients, 27 males and 9 females were enrolled in the study. The ages of the patients ranged from 33 to 80 years with a mean age of 55 +/- 12 years. Forty-seven per cent of patients had hyperfunction of platelet before treatment which fell to 3 and 0 per cent 24 hours and 7 days after low dose aspirin treatment (75 mg/d). The platelet count was significantly increased to compensate its hypofunction after seven days of treatment. There was no change in euglobulin lysis time, serotonin level in platelet after low dose aspirin treatment. Plasma prostacyclin in ischaemic stroke patients was statistically significantly reduced in comparison to normal subjects (223.8 pg/ml); but there was no further suppression of plasma prostacyclin after low dose aspirin therapy. Thus, we conclude that low dose aspirin (75 mg/d) is effective for antithrombotic effect in ischaemic stroke patients without any suppression of prostacyclin. We do recommend low dose aspirin for recurrent ischaemic stroke prophylaxis as it has fewer side effects, is cheap, easily administered and effective.

Clinical study on antithrombotic effects of ticlopidine in ischemic stroke.

The investigators conducted a clinical study on antithrombotic effectiveness in ischemic stroke at Siriraj Hospital Medical School, Mahidol University from May 1987 to May 1989. Twenty-nine patients, 16 males and 13 females were enrolled in the study. The ages of the patients ranged from 30-87 years with a mean age of 63 +/- 11 years. Ticlopidine (250 mg) could significantly inhibit platelet aggregation induced by ADP and collagen within 24 hours of drug administration. After 1 week to 6 months, only aggregation by ADP was still inhibited significantly without significant effects on fibrinolytic activity and prostacyclin. Hematocrit was significantly decreased at the 1st and 2nd month of treatment. Serious side effects were skin rash and severe headache while the other common ones were dizziness, and diarrhea but these effects disappeared without discontinuing the drug. Most patients who suffered from nausea, diarrhea and headache, had temporary elevated SGPT. It may be concluded that only half of the recommended dose of ticlopidine has inhibitory effects on both phases of ADP-induced aggregation without interfering with fibrinolytic activity and can maintain prostacyclin. However, it also possesses either serious or common side-effects. This drug, therefore, should be used with the awareness of the clinician.

Effect of land preparation methods on growth, seed yields of Jasmine 105 paddy rice (Oryza sativa L.) and growth of weeds, grown in Northeast Thailand.

This experiment was carried out on a grower's paddy field, Ban Som Hoeng Village, Kantarawichai, Mahasarakham Province, Northeast Thailand with the use of Roi-Et soil series (Oxic Paleustults) in the rainy season of the 2006 (May to November) to investigate effect of land preparation methods on rice plant heights, amounts of weeds and seed yields of Jasmine 105 aromatic paddy rice (Oryza sativa L.). The experiment was laid in a Randomized Complete Block Design (RCBD) with four replications. The results showed that plant height due to treatments was significantly highest for T3 but T3 was similar to T2, whilst T1 (control) was the least. Mean values of dry weight of narrow leaf type of weeds, in most cases, were significantly lowest with T3 followed by T2 and T3, particularly at the final two sampling periods. Broad leaf type of weeds was significantly highest with T2 throughout the experimental period, whilst T1 and T3, in most cases, were similar. Unfilled seeds were significantly highest with T3 but similar to T1 but T2 was the lowest, whilst filled seeds were significantly highest with T3, both T1 and T2 gave a similar weight. Numbers of panicles m(-2) were significantly highest with T3 but T3 was similar to T2, whilst T1 was the least. Seed size or 1000-seed weight was significantly highest with T3, whilst T2 and T1 were similar. Seed yield was highest and highly significant with T3 (1,136.25 kg ha(-1)) but T3 was similar to T2 (1,083.31 kg ha(-1)), whilst T1 was the lowest (487.50 kg ha(-1)). Land preparation method of T3 treatment may be recommended as the first choice, whilst T2 may be used as an alternative choice.

Residual effects of applied chemical fertilisers on growth and seed yields of sunflower (Helianthus annuus cv. high sun 33) after the harvests of initial main crops of maize (Zea mays L.), soybean (Glycine max L.) and sunflower (Helianthus annuus).

The experiments consisted of two locations, i.e., the first one was carried out on a growers's upland area at Saraburi Province, Central Plane region of Thailand with the use of Chatturat soil series (Typic Haplustalfs, fine, mixed) and the second experiment was carried out at Suranaree Technology university Experimental Farm, Suranaree Technology University Northeast Thailand with the use of Korat soil series (Oxic Paleustults). The experiments aimed to investigate the effect of residual effects of applied chemical fertilisers on growth and seed yields of sunflower (Helianthus annuus) after the harvests of initial main crops of maize, soybean and sunflower. The experiments consisted of four cultural methods being practiced by growers in both regions. For Methods 1 and 2, each had four fertiliser treatments; Method 3 consisted of two fertiliser treatments and Method 4 was used as a control treatment. The results showed that soil pH, organic matter and nutrients of Korat soil series were most suited soil conditions for growth of sunflower plants, whilst that of Chatturat soil series at Saraburi province was an alkaline soil with a mean value of soil pH of 7.8. Chatturat soil series, in most cases, gave higher amounts of seed yields (1,943.75 kg ha(-1)) than Korat soil series. Residual effects of applied chemical fertilisers to main crops of soybean gave better growth and seed yields of sunflower plants and it is considered to be the first choice. The use of sunflower and maize as main crops gave a second choice for subsequent crop of sunflower.

Effects of crop residues of sunflower (Helianthus annuus), maize (Zea mays L.) and soybean (Glycine max) on growth and seed yields of sunflower.

This pot experiment was carried out at Suranaree Technology University Experimental Farm, Northeast Thailand to investigate effects of crop residues of sunflower, maize and soybean on total dry weight, top dry weight, plant height, root dry weight and seed yield of sunflower plants with the use of Korat soil series (Oxic Paleustults) during the rainy season (July-October) of the 2001. The experiment was laid in a split plot arranged in a Completely Randomized Design (CRD) with four replications where the crop residues of maize, sunflower and soybean were used as main plots. Whilst crop residues of roots, top growth and roots+top growth were used as subplots. The results showed that crop residues derived from roots of both sunflower and soybean plants had their significant inhibition effects of allelopathic substances on plant height, root dry weight, top growth dry weight and total dry weight plant(-1) of the sunflower plants than those derived from top growth of both crops alone (sunflower and soybean). Maize plant residues had no significant inhibition effect on growth of subsequent crop of sunflower.