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Biomedical subjects

Visith Sitprija

Publications and source records attributed to Visith Sitprija.

35 records · Page 2Linked to original sources
PubMed2003

The impact of a low dose, low volume, multi-site immunization on the production of therapeutic antivenoms in Thailand.

Therapeutic antivenom against snakes was first produced by Albert Calmette in 1894. Since then antivenoms have saved the life of countless snakebite victims. However, there are still many problems associated with antivenom production, for example variable percentage of responder horses, low neutralizing potency of antivenom, the large amount of snake venom needed for immunization and the difficulties encountered in producing potent polyvalent antivenoms. These problems have led to shortage and high cost of antivenom and, in some cases, failure of treatment. In 1997, a new immunization protocol for antivenom production was reported. It involves the injection of venom at low dose (approx. 2mg/horse) emulsified in Complete Freund's adjuvant in low volume (0.1-0.2 ml/site) in a total of 10 sites around the neck area of the horse. This immunization protocol has minimized the local reaction at the injection site thus allowing the use of the potent oil adjuvant. This, together with the increase in total surface area of the droplets, allow a more effective immune response to take place, e.g. enhancing the migration and activation of more antigen presenting cells and lymphocytes. The low dose, low volume multi-site immunization has resulted in dramatic improvements on the antivenom production in terms of amount of venom used for immunization, the time required to reach hyperimmune stage, the percent of responder horses and the potency of the antivenom. Furthermore, this protocol has made it possible to produce potent truly polyvalent antivenoms against several elapid and viperid snakes. This immunization protocol has alleviated various problems associated with antivenom production and has implications for immunization in general.

Animals↗
PubMed2003

Antihemorrhagin in the blood serum of king cobra (Ophiophagus hannah): purification and characterization.

King cobra (Ophiophagus hannah) serum was found to possess antihemorrhagic activity against king cobra hemorrhagin. The activity was stronger than that in commercial king cobra antivenom. An antihemorrhagin has been purified by ion exchange chromatography, affinity chromatography and gel filtration with a 22-fold purification and an overall yield of 12% of the total antihemorrhagic activity contained in crude serum. The purified antihemorrhagin was homogeneous in disc-PAGE and SDS-PAGE. Its apparent molecular weight determined by SDS-PAGE was 120 kDa. The antihemorrhagin was also active against other hemorrhagic snake venoms obtained in Thailand and Japan such as Calloselasma rhodostoma, Trimeresurus albolabris, Trimeresurus macrops and Trimeresurus flavoviridis (Japanese Habu). It inhibited the proteolytic activity of king cobra venom. It is an acid- and thermolabile protein and does not form precipitin lines against king cobra venom.

Animals↗
PubMed2003

Potassium depletion in a healthy north-eastern Thai population: no association with tubulo-interstitial injury.

Potassium depletion prevails among the healthy population of north-east Thailand, as well as among patients with certain metabolic disorders such as upper urinary tract stones, the sudden unexplained death syndrome, distal renal tubular acidosis and hypokalaemic periodic paralysis. However, definite proof of the relationship of potassium depletion and these metabolic disorders is lacking. We prospectively studied muscle and kidney potassium content including renal tissue pathology in three groups of healthy adult Thai subjects who died of vehicular accidents. Group 1 (n = 24) were Bangkok city dwellers; groups 2 (n = 10) and 3 (n = 22) lived in north-eastern Thailand in the metropolitan area and in the villages, respectively. The muscle potassium content of group 1 (338.5 +/- 9.6 mEq/kg dry weight (DW)) were similar to group 2 (307.9 +/- 11.9 mEq/kg DW), but was greater than group 3 (295.4 +/- 9.1 mEq/kg DW; P < 0.01). The kidney potassium content of group 1 (208.6 +/- 7.8 mEq/kg DW) was significantly higher than group 3 (175.9 +/- 6.3 mEq/kg DW, P < 0.05). In group 3, the muscle potassium correlated linearly with the kidney potassium (r = 0.455, P = 0.33). None of the group 3 patients had renal histopathological change compatible with a diagnosis of focal or diffuse interstitial nephritis. This study confirms that potassium depletion is common among healthy rural dwellers in north-east Thailand. This deficit was probably chronic. However, there was minimal renal tubulo-interstitial change.

Adolescent↗
PubMed2003

Nephrology in South East Asia: fact and concept.

The developing countries of South East Asia lie within the tropics. Renal disease in this region represents the interaction between the kidney and the environment abetted by low levels of socioeconomic development in many areas. Together with genetic susceptibility to some diseases, there are widespread infectious diseases and prominently encountered plant and animal toxins. Chronic renal failure, most commonly the outcome of chronic glomerulonephritis and frequently to persistent nephrolithiasis as well as acute renal failure due to a variety of stimuli, are among the most common renal problems encountered. Renal replacement therapy is both a clinical and economic problem. The epidemiology of renal disease in the region is poorly understood, and workforce and treatment facilities are not adequate for the caseload in a number of countries in the region. Many people with chronic renal disease simply cannot afford the necessary treatment. The principle focus for the future must be on prevention strategies and the provision of appropriate health services within the current economic and technological restraints.

Asia, Southeastern↗
PubMed2003

Overview of tropical nephrology.

Tropical nephrology covers renal diseases commonly seen in the tropics and elsewhere and specific tropical renal diseases seen mostly or only in the tropical area. Emphasis in this article is placed on the latter category, which includes renal involvement in tropical infectious diseases, natural toxin poisoning, and environmental renal problems. Pathologically, all renal structures can be affected. There is, therefore, a broad spectrum of pathologic changes, and clinical renal manifestations vary from mild urinary sediment changes to acute renal failure. Inflammatory processes plays an essential role in the pathogenesis of renal involvement in infection and toxin groups. Both models share the same inflammatory pathways through cytokines, chemokines, and mediators. Hemodynamic alterations, immune response, and direct nephrotoxicity are involved in the development of renal lesions.

Female↗
PubMed2003

Leptospiral nephropathy.

Renal involvement is common in leptospirosis. Clinical manifestations vary from urinary sediment changes to acute renal failure. Renal failure is observed in 44% to 67% of patients. Hypokalemia frequently occurs. Severe hypotension is an important warning sign for the later development of renal and pulmonary complications. Prognosis of the disease is generally good except for its association with pulmonary complications, especially pulmonary hemorrhage and acute respiratory distress syndrome. Interstitial nephritis is the basic renal lesion. Vasculitis is observed in the acute phase of the disease. Tubular necrosis and interstitial nephritis are responsible for renal failure. Glomerular changes usually are not remarkable. Hemodynamic alterations, immune response, and direct nephrotoxicity are responsible for the development of renal lesions. As in many infectious diseases, decreased renal blood flow and glomerular filtration rate play a basic role. Bacterial invasion and toxicity of outer membrane with generation of cytokines, chemokines, and cellular infiltration are important in cellular injury.

Comorbidity↗
PubMed2003

Isolation, toxicity and amino terminal sequences of three major neurotoxins in the venom of Malayan krait (Bungarus candidus) from Thailand.

We isolated the most lethal toxins in the venom of the Malayan krait (Bungarus candidus), one of the medically most important snake species in southeast Asia. Three beta-BTx like basic neurotoxins, T1-1, T1-2, and T2, with PLA2 activity were isolated from pooled venom of eight B. candidus from southern Thailand by cation-exchange chromatography, followed by adsorption chromatography on hydroxylapatite and RP-HPLC, with 14-, 16-, and 4-fold increases in toxicity compared to crude venom. The LDs50 determined in mice weighing 18-20 g were 0.26, 0.22, and 0.84 micro g per mouse with i.v. injection. T1-1 and T1-2 possessed comparable lethal toxicities to those of beta1-BTx, the most toxic neurotoxin in B. multicinctus venom, and the major neurotoxin in B. flaviceps venom. The apparent molecular weights of the native toxins were approximately 25-25.5 kDa. They consist of two polypeptide chains with apparent molecular weights of 15.5-16.5 and 8-8.5 kDa, respectively. The amino terminal sequences of the two chains of each of the toxins determined by Edman degradation exhibited considerable similarity with those of the A-chains and B-chains of beta-BTxs in the venom of Bungarus multicinctus.

Amino Acid Sequence↗
PubMed2003

Medical residency training in the US: important considerations.

The United States attracts medical scholars from abroad. However, the previously open-armed welcome extended to medical residents in America no longer exists for a variety of reasons. A series of barriers based on high educational standards and a rigid system of testing scientific and clinical skills and communication abilities, now tend to eliminate many applicants. Added to this is that American medical colleges now produce a near adequate number of new graduates and that foreign trained residents are often relegated to less desirable programs. These may not provide the level of training expected by the applicant. Less attractive programs are also less likely to enhance the scholar's chances of gaining an academic career and professional recognition on returning home. Applicants for residencies in the US should now be aware that only the best are likely to gain entrance to highly desired posts and to quality fellowships after completing a residency in America. All of this should be weighed against the stress and high costs that are now entailed in obtaining postgraduate medical training in America. This study endeavors to summarize what a young doctor should know about the application process for an American residency position and what he might expect from it.

Clinical Competence↗
PubMed2003

Oral bacterial flora of dogs with and without rabies: a preliminary study in Thailand.

The authors studied the bacterial flora of the dog oral cavity and of bite wounds, Aerobic bacteria were isolated from mouth swabs of 16 normal and 5 rabid dogs as well as from infected dog-bite wounds from 18 patients. A total of 20 different microbial species were recovered from mouth swab cultures. The most frequently isolated organisms were Klebsiella pneumoniae ssp pneumoniae, Escherichia coli, Staphylococcus aureus, Citrobacter freundii, Enterobacter cloacae, Acinetobacter calcoaceticus, and Pasteurella species. There were no differences in the aerobic bacterial flora between rabid and nonrabid dogs. From the cultures of the bite wound swabs, the authors found that almost all of the organisms identified were part of the normal oral flora of the dog. One or more aerobic bacteria were isolated from the infected dog-bite wounds. Two patients had four, 3 had three, 4 had two, and 6 had one of the nine organisms in their wounds. The predominant species of bacteria involved in infection of bite wounds were, as follows: Staphylococcus aureus, Pasteurella multocida, E. coli, Moraxella species, Pasteurella canis, and Enterobacter cloacae. However, three wound cultures had no aerobic bacterial growth. The results of this study show that the infected bite wounds may contain a mixed bacterial flora that colonize human skin and the oral cavity of dogs.

Animals↗
PubMed2002

Postexposure treatment of rabies infection: can it be done without immunoglobulin?

The last remaining international manufacturer of equine rabies immunoglobulin (ERIG) discontinued production in 2001. However, ERIG remains an essential biological that has no substitute other than human rabies immunoglobulin (HRIG), which is in short supply and virtually unaffordable in developing countries. Physicians in regions where canine rabies is endemic and neither ERIG nor HRIG is available are providing less-than-optimal treatment to patients exposed to rabies. If no immunoglobulin is available, they have only 1 therapy option: use of a vaccine schedule that produces the highest and, hopefully, earliest neutralizing antibody response. However, treatment failures must still be expected. Early, aggressive wound cleansing and more intensive efforts at canine control and are ever more important. Countries that have the resources to manufacture their own rabies immunoglobulins must be encouraged to do so.

Animals↗
PubMed2002

Comorbidities in patients with end-stage renal disease in developing countries.

Patients with end-stage renal disease (ESRD) who are on renal replacement therapy (RRT) usually have a certain number of comorbid factors. Cardiovascular diseases are the most common comorbidities and the most common causes of mortality in ESRD patients. Noncardiovascular comorbid factors including nutrition also have impact on survival of ESRD patients on RRT. There are scarce data regarding comorbidity in developing countries. Available data have shown that hypertension, diabetes, and various cardiovascular disorders are the leading comorbidities. Improvement in outcome for ESRD patients would depend on improving quality in RRT as well as a better understanding and management of comorbid conditions.

Asia↗
PubMed2002

Hypotension, renal failure, and pulmonary complications in leptospirosis.

During a recent outbreak of leptospirosis in northeastern Thailand, 148 patients with serologically diagnosed leptospirosis were seen in Loei hospital. The common serotypes were L. pyrogenes, and L. sejroe. Hypotension with a mean arterial pressure less than 70 mmHg upon admission or within 24 h after admission was observed in 94 patients or 64%. 30 patients had normal renal function; 30 patients had prerenal azotemia with mild pulmonary complication in 2; and 34 patients had acute renal failure. 29 patients with acute renal failure had pulmonary complications including pulmonary hemorrhage in 8, pulmonary edema in 3, acute respiratory distress syndrome (ARDS) in 14 and interstitial pneumonitis in 4. 54 patients had normal blood pressure. In this group 5 patients had acute renal failure; 16 had prerenal azotemia and 33 had normal renal function. Interstitial pneumonitis was noted in one patient with prerenal azotemia. Less renal complication and minimal pulmonary complication were seen in leptospirosis patients with normal blood pressure. The patients with normal renal function had no pulmonary complication. Good association existed between hypotension, renal failure and pulmonary complications.

Acute Kidney Injury↗
PubMed2002

Leptospirosis in northeastern Thailand: hypotension and complications.

During an outbreak of leptospirosis in northeastern Thailand, 148 patients with serologically diagnosed leptospirosis were seen in Loei Hospital. The clinical features were consistent with those described for the classic manifestation of the disease. However, hypotension was a common finding: noted in 94 patients (64%) upon admission or early in the course of the disease. Of these hypotensive patients, 64 (68%) had impaired renal function: 30 patients (32%) had prerenal azotemia and 34 (36%) were in renal failure. Pulmonary complications, including pulmonary edema, hemorrhage, ARDS, and interstitial pneumonitis, occurred in 22% of patients and were often associated with renal failure. A clear association existed between hypotension and renal failure and pulmonary complications. The overall mortality rate was 3.4%. The causes of death were pulmonary complications, renal failure, and sepsis. The death rate among patients with complications was 11.6%. Blood exchange, in addition to conventional treatment, was beneficial in severe leptospirosis with complications and hyperbilirubinemia.

Adult↗
PubMed2002

Magnesium and zinc status in survivors of sudden unexplained death syndrome in northeast Thailand.

Sudden Unexplained Death Syndrome (SUDS) is a major health problem in rural residents of Northeast Thailand. The cause of death in SUDS is suspected to be cardiovascular abnormalities. As magnesium (Mg) and zinc (Zn) deficiency contribute significantly to several cardiovascular diseases, we investigated the Mg- and Zn-status of patients with sudden respiratory distress and cardiac arrest who had survived resuscitation attempts or a near-SUDS episode (N-SUDS). The following subjects were enrolled: 12 N-SUDS inhabitants of rural Northeast Thailand (rural group 1, R1), 13 rural villagers with no past history of N-SUDS (rural group 2, R2), 15 urban Northeasterners (urban group 1, U1); 13 Bangkokians (urban group 2, U2). All subjects were free of structural heart disease. Magnesium and zinc were assessed by atomic absorption spectrophotometry of samples of plasma, red blood cells (RBC), white blood cells (WBC), and 24-hour urine. The mean levels of magnesium in the RBC, WBC, and 24-hour urine of N-SUDS patients (R1) were significantly lower than those of the urban groups (U1 and U2), while the plasma levels did not show any differences. When comparing the Zn-status of R1 with that of the urban groups (U1 and U2), the plasma, RBC, and WBC levels were found to be significantly lower in R1 (except for the RBC-Zn of the U1 group), while the 24-hour urine levels was higher. Although the magnesium and zinc parameters were not significantly different between the rural groups R1 and R2, the prevalence of hypomagnesuria (<2.2 mmol/day), hypozincemia (<9.7 micromol/l), and hyperzincuria (>10.7 micromol/day) was higher in the R1 group. These findings suggest that the homeostasis of both magnesium and zinc is altered in N-SUDS patients. Similar alterations, to a lesser degree, were observed in those people living in the same rural environment (R2).

Death, Sudden, Cardiac↗
PubMed2002

Capacity of Thai green pit viper antivenom to neutralize the venoms of Thai Trimeresurus snakes and comparison of biological activities of these venoms.

The capacity of Thai green pit viper antivenom raised to Trimeresurus albolabris to neutralize the venoms from six species of Trimeresurus sp. in Thailand has been examined. They were Trimeresurus albolabris, T. macrops, T. popeiorum, T. hageni, T. purpureomaculatus, and T. kanburiensis. The antivenom neutralized lethal and hemorrhagic activities of all these venoms. The capacity of antivenom to neutralize lethal toxicity of the venom was expressed as the amounts (mg) of snake venom neutralized by 1 ml of the antivenom. The largest capacity was found with the homologous venom. Results of immunodiffusion, immunoblotting, and antigen-antibody complex formation experiments supported the results of neutralization experiments. Several biological activities of the Trimeresurus venoms were also examined and compared. They were lethal, hemorrhagic, proteolytic, phospholipase A, arginine ester hydrolyse, and thrombin activities. There was no correlation between the ratios of lethal toxicity and hemorrhagic activity, lethal toxicity and phospholipase A activity, as well as hemorrhagic activity and proteolytic activity.

Animals↗
PubMed2002

A pilot experiment for production of Malayan krait antivenom: immunization of rabbits with Bungarus candidus venom.

Immunization with Bungarus candidus venom was performed in four rabbits at high dose (initial dose, 75 microg/kg) and low dose (initial dose, 50 microg/kg). Each dose group consisted of two rabbits; one rabbit received the venom subcutaneously (s.c.) and the other intradermally (i.d.). The venom was injected as emulsified solutions with the same volume of Freund's complete adjuvant until the 4th immunization, thereafter as plain solutions. By stepwise increments of the immunizing dose, the higher dose group received a dose of 200 microg/kg and the lower dose group 150 microg/kg after the 5th immunization, respectively. Thereafter, seven additional immunizations were performed within six months. All rabbits were sacrificed two weeks after the last immunization (12th). Antilethal activity of the immunized antisera thus obtained was determined not only with the homologous venom but also with two heterologous venoms from Bungarus fasciatus and Bungarus flaviceps. Immunodiffusion analysis was also performed with these venoms. The results obtained in this pilot trial provided useful information for production of Malayan krait antivenom at Queen Saovabha Memorial Institute.

Animals↗