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Biomedical subjects

Visith Sitprija

Publications and source records attributed to Visith Sitprija.

At least 19 recordsLinked to original sources
PubMed2006

Effects of Russell's viper venom fractions on systemic and renal hemodynamics.

Changes in systemic and renal hemodynamics induced by Russell's viper venom are well established. The component of the venom responsible for hemodynamic alteration has not been identified. By Sephadex column chromatography five fractions of Russell's viper (Daboia russellii siamensis) venom were isolated. Each venom fraction consisted of phospholipase A2, proteolytic enzyme, phosphomonoesterase, phosphodiesterase, arginine ester hydrolase and hyaluronidase of varying activities. Hemodynamic effects of each venom fraction including mean arterial pressure, cardiac output, systemic and renal vascular resistance, renal blood flow and glomerular filtration rate were studied in five groups of dogs; each group had four dogs. Minimal hemodynamic changes were observed in dogs receiving venom fraction I. Increased renal vascular resistance with diminution of renal blood flow and glomerular filtration rate was observed in dogs receiving venom fractions II, III, IV and V. A markedly increased renal vascular resistance with maximal decrease in renal blood flow and glomerular filtration rate was caused by fraction III of the venom with highest PLA2 and proteolytic enzyme activities. However, renal hemodynamic changes appeared to correlate better with proteolytic enzyme activity than PLA2 activity. The findings suggested the proteolytic enzyme as an important determinant of hemodynamic alteration. Fractional excretion of Na was increased in dogs injected with venom fraction IV, and is presumed to be due to the inhibition of tubular reabsorption of Na by a natriuretic factor in this venom fraction.

Animals↗
PubMed2006

Revision of the Thai Red Cross intradermal rabies post-exposure regimen by eliminating the 90-day booster injection.

The Thai Red Cross intradermal post-exposure rabies prophylaxis regimen (TRC-ID) is being used in Thailand, the Philippines, Sri Lanka and is making inroads in India. It consists of two injections of 0.1 mL of any World Health Organization recommended tissue culture rabies vaccine intradermally at two sites on days 0, 3, 7, followed by one injection on days 28 and 90. Two decades of experience had shown that approximately 11% of 187,000 possibly rabies exposed subjects who received the TRC-ID schedule, did not return for the 90-day booster. No rabies deaths had, however, been reported from this group. This stimulated two studies to determine whether the 90-day booster can be abolished. They demonstrated that, if the single 28-day 0.1 mL injection is increased to two at two sites, a comparable antibody response can be achieved and the 90-day booster can be omitted. The tissue culture rabies vaccine used in the preliminary study was purified chick embryo vaccine (PCEC Chiron) and for this study it was chromatography purified Vero cell vaccine (CPRV, Aventis-Pasteur). CPRV had been previously shown to be as immunogenic and effective as purified Vero cell rabies vaccine (PVRV).

Antibodies, Viral↗
PubMed2006

Molecular cloning of the major lethal toxins from two kraits (Bungarus flaviceps and Bungarus candidus).

The major lethal toxins present in the venoms of the red-headed krait, Bungarus flaviceps, and the Malayan krait, Bungarus candidus, have both been purified. Each consists of two polypeptide chains, A and B, joined by a disulfide bond. In the present study, primary structures of these toxins were determined by Edman degradation and by nucleotide sequencing of the cDNA clones. Amino acid sequencing of the N-terminus and enzymatically digested peptides revealed that the A and B chains were highly homologous to those of beta-bungarotoxins (beta-Bgts) from Bungarus multicinctus, respectively. We isolated cDNA clones encoding the A and B chains from both B. flaviceps and B. candidus venom gland cDNA libraries using probes designed based on the cDNA sequence of beta-Bgt from B. multicinctus. Two isoforms of the A chain and one isoform of the B chain were obtained from B. flaviceps, and one isoform of the A chain and two isoforms of the B chain were obtained from B. candidus. Both of the two A chains from B. flaviceps are made up of 119 amino acids and comprise 15 cysteine residues, while the A chains of beta-Bgt from other Bungarus species including B. candidus comprise 13 cysteine residues. The B chains from both species are composed of 59 amino acid residues and comprise seven cysteines. In conclusion, the lethal toxin from B. flaviceps is considered to be a novel isoform of beta-Bgt, which has a different pattern of cysteine residues from known beta-Bgts.

Amino Acid Sequence↗
PubMed2006

Snakebite nephropathy.

There is a broad clinical spectrum of renal involvement in snakebite. Besides the local and systemic symptoms, clinical renal manifestations vary from mild proteinuria, haematuria, pigmenturia to acute renal failure. Bites by haemotoxic snakes and myotoxic snakes are the common causes of renal involvement especially acute renal failure. Therefore, renal failure is often associated with haemorrhagic diathesis, intravascular haemolysis and rhabdomyolysis. Renal pathological changes include mesangiolysis, glomerulonephritis, vasculitis, tubular necrosis, interstitial nephritis and cortical necrosis. Tubular necrosis is an important pathological counterpart of acute renal failure. Haemodynamic alterations induced by cytokines and vasoactive mediators leading to renal ischaemia are important in the pathogenesis of acute renal failure. Haemolysis, intravascular coagulation and rhabdomyolysis are important contributing factors. Direct nephrotoxicity can be induced by the venom through metalloproteases and phosphilipase A2. Immunologic mechanism plays a minor role in the pathogenesis of the renal lesion.

Animals↗
PubMed2006

Is injecting a finger with rabies immunoglobulin dangerous?

Treating potentially rabies virus infected wounds requires the injection of rabies immunoglobulin into and around the wounds, followed by vaccination with an approved tissue culture rabies vaccine. A significant number of such bite wounds involves fingers where there is little space for expansion. Injecting immunoglobulin into such areas under pressure may induce a compartment syndrome caused by compromising circulation. We carried out a retrospective review and a prospective study of patients seen with digital bite injuries and found that it is a safe procedure if carried out with care by experienced staff.

Adolescent↗
PubMed2005

Rabies control in South and Southeast Asia.

We have the knowledge and tools to eliminate the threat of canine rabies but this disease, nevertheless, remains a public health threat in many parts of the world. Lack of motivation by governments, cultural issues and inadequate funding remain barriers. This is amazing since the number of human rabies deaths worldwide is greater than that from polio, meningococcal meningitis, Japanese encephalitis, yellow fever, SARS, bird flue and other scourges that attract more attention. Safe and effective vaccines are now widely available. Reduced dose effective and less expensive post-exposure vaccination regimens have helped eliminate nerve tissue vaccines in Thailand, Philippines and Sri Lanka. India and Pakistan, the major users of dangerous nerve tissue derived Semple type vaccine, are now considering following suite. Immediate wound care and prompt use of a potent vaccine will save a majority of infected persons. Rabies immunoglobulin, injected into and around bite wounds, provides added safety for the severely exposed. The high cost of rabies immunoglobulin and tissue culture vaccines are remaining barriers, but new manufacturers and the use of intradermal vaccination schedules can reduce costs. Ultimately, it is the need to control rabies in dogs that must occupy most of our attention. The tools are available, but attitudes must change before they can be applied. There have been many new developments since publication of the last WHO rabies expert committee report in 1992 (new version in print)] and we will address those that have practical applicability.

Animals↗
PubMed2005

Adverse reactions to human rabies immune globulin manufactured by the Thai Red Cross Society.

Rabies Immunoglobulins (RIG) are an essential part of optimal management of rabies exposures [World Health Organization (WHO)]. They provide protection against the virus during the critical initial 7 days before adequate endogenous vaccine induced antibodies are formed. Even though Human Rabies Immune Globulin (HRIG) is the ideal product for post-exposure rabies treatment it, like most biological, can cause very rare adverse reactions. A retrospective review of a series of 8737 patients, who received HRIG at one institution, revealed that only 15 (0.183 %) reported transient mild adverse reactions.

Adolescent↗
PubMed2005

Haemodynamics in leptospirosis: effects of plasmapheresis and continuous venovenous haemofiltration.

BACKGROUND: Haemodynamics in leptospirosis may differ from that of sepsis because of frequently obeserved myocarditis and severe cholestatic jaundice. A haemodynamic study was therefore made in 10 patients with severe leptospirosis. METHODS AND RESULTS: All patients had pulmonary complications with a chest X-ray showing either pulmonary oedema or infiltration. Renal failure was present in nine patients. Three patterns of haemodynamics were revealed. The first pattern was observed in six patients who showed increased cardiac index, decreased systemic vascular resistance, normal pulmonary capillary wedge pressure, normal pulmonary vascular resistance and hypotension. The pattern resembled that of sepsis. The second pattern shown in two patients with haemoptysis consisted of a normal cardiac index, normal systemic vascular resistance, normal blood pressure, normal pulmonary capillary wedge pressure and increased pulmonary vascular resistance. The third pattern was observed in two patients with severe jaundice who had hypotension, a relatively low cardiac index, increased systemic vascular resistance and normal pulmonary capillary wedge pressure, and pulmonary vascular resistance. Plasmapheresis performed in two patients and continuous venovenous haemofiltration performed in two patients improved systemic haemodynamics and normalized blood pressure with a resolution of lung signs.

Adult↗
PubMed2005

Enteric fever-like illness caused by infection with citrobacter amalonaticus.

'Enteric fever' is a potentially fatal, severe systemic disease, which is encountered worldwide. Traditionally, enteric fever refers to a bacteremic illness caused by members of certain Salmonella serotypes, notably: Salmonella typhi, a Gram-negative bacterium, and to a lesser extent, Salmonella paratyphi A, B and C. In addition, other non-salmonella organisms may produce a syndrome clinically indistinguishable from "enteric fever". Brucella sp., Campylobacter sp., Edwardsiella tarda, Enterobacter Cloacae, Escherichia coli, Klebsiella pneumoniae, Providencia alcalifaciens, Pseudomonas sp., Serratia marcescens, Francisella sp. and Yersinia pp have been identified in enteric fever This is, to the best of the authors' knowledge, the first case of Citrobacter to be reported presenting as enteric fever in a normal host in Thailand.

Citrobacter↗
PubMed2005

Etiologies of glomerular diseases in Thailand: a renal biopsy study of 506 cases.

BACKGROUND: The nationwide renal registry has not yet been organized in Thailand, and the literature contains no registry of renal pathologic finding across the Southeast Asian (SEA) countries in the modern era when electron microscopy (EM) is routinely available. OBJECTIVE: The aim of the present study was to examine the prevalence of renal pathology in Thai population. MATERIAL AND METHOD: The authors reviewed the case file and renal biopsy specimens of King Chulalongkorn University Hospital to identify all adult native renal biopsy specimens received from January 2001 to December 2004, investigating prevalence and clinical and histological data. Biopsy of renal graft and in cases of trauma and tumors the authors excluded. Most of the biopsy specimens obtained The authorsre analyzed using light microscopy (LM), immunofluorescense (IF), and EM. Final diagnosis was made for each patient based on clinicopathologic correlations. RESULTS: A total of 506 native renal biopsies were processed during this period, 69.8% were female and 30.2% were male. Their age average was 37 +/- 14.2 (13-80) years. The most common indications for renal biopsy were nephrotic syndrome and SLE (36.8%, 34.5%, respectively), followed by asymptomatic hematuria/proteinuria in 10.9% of patients. Secondary glomerular diseases were dominant against primary diseases in all but elderly age group (>50 years), particularly LN. Among primary glomerular diseases, the prevalence of IgAN, focal segmental glomerulosclerosis, and membranous nephropathy were 31.0%, 24.9%, and 13.1%, respectively. The provisional clinical diagnosis was correct in three fourths (73.2%) of the SLE cases. Postbiopsy complications occurred in 3.3% (17/506). Gross hematuria was seen in 2.3% (12/506), and perinephric hemptoma in 0.79%. Three of them required blood transfusion but none of them died and required an invasive procedure for resolution. The major complications were 2 folds less than regular prevalence (0.6% compared to 1.3%). CONCLUSION: Although the data was collected from single center where EM is routinely performed, the authors believe that IgAN is the commonest primary GN in SEA countries. The authors are looking forward to seeing the nationwide registry data in Thailand and other SEA countries.

Adolescent↗
PubMed2004

Survival of naturally infected rabid dogs and cats.

A total of 1820 dogs and 332 cats that appeared ill or had bitten humans or animals were observed for >or=10 days. Of these, 957 dogs and 94 cats that were confirmed to be rabid survived <10 days after admission to our institution. This study supports current recommendations that dogs and cats that are suspected of being rabid should be euthanized and examined or, if this is inappropriate, confined and observed for 10 days.

Animals↗
PubMed2004

Genetic typing of feline rabies virus isolated in greater Bangkok, Thailand.

To study the molecular epidemiology of rabies virus that is prevalent among cats in greater Bangkok, Thailand, a total of 17 rabies virus isolates from cats were characterized and compared with 120 rabies virus isolates from dogs. Analyses were performed on the genetic polymorphism in the rabies virus nucleoprotein (N) gene. Rabies virus N gene of isolates was amplified by reverse transcriptionpolymerase chain reaction. The diversity of N gene was revealed by the restriction fragment length polymorphism (RFLP) method. The rabies virus isolates from cats could be classified into 5 types, designated as Dd I-Hf I, Dd II-Hf II, Dd III-Hf I, Dd IV-Hf I, and Dd IV-Hf III. Type Dd I-Hf I was encountered more frequently than the others. It was apparent that no less than five rabies virus types presented in the areas of Bangkok. Moreover, all five RFLP patterns were typical of those which had been observed in dogs. Our findings suggest that there had been viral transmission between the dogs and the cats.

Animals↗
PubMed2004

Acute hypercalcemia-induced hypertension: the roles of calcium channel and alpha-1 adrenergic receptor.

OBJECTIVE: To study the mechanism(s) of acute hypercalcemia-induced hypertension in dogs. MATERIAL AND METHOD: Adult male mongrel dogs were intravenously infused with: 1) normal saline solution, 2) CaCl2 solution, 3) CaCl2 + calcium channel blocker (verapamil), 4) CaCl2 + selective alpha-1 adrenergic receptor blocker (prazosin), or 5) CaCl2 + verapamil + prazosin. Either verapamil or prazosin treatment was started at forty minutes before CaCl2 infusion and then was co-administered throughout the three-hour experimental period. Systemic and renal hemodynamics parameters were determined. RESULTS: Infusion of CaCl2 caused increases in mean arterial blood pressure (p < 0.01), total peripheral resistance (p < 0.001), and renal vascular resistance (p < 0.001). Prior treatment with either verapamil or prazosin lowered baseline blood pressure (p < 0.01) and could prevent hypercalcemia-induced hypertension. This occurred accompanying regaining to near normal values of abnormal systemic hemodynamics parameters. Combination of both drugs showed more profound effects, particularly on lowering renal vascular resistance. CONCLUSION: Acute hypercalemic hypertension is caused by an increase in vascular resistance mediated via the direct effect of calcium on vascular smooth muscle as well as the indirect effect of calcium induced hypercatecholaminemia. The stimulatory effect of hypercalcemia on renal vascular resistance is more prominent than that on peripheral vascular resistance.

Acute Disease↗
PubMed2003

Rabies update for travel medicine advisors.

Rabies is a neglected disease in many developing countries. It is preventable, and the tools to prevent it are known. There is urgent need for more funding, for study of innovative dog population-control measures, and for sustainable canine immunization. Safe and effective tissue-culture rabies vaccines and human and equine rabies immunoglobulins (HRIG and ERIG) are not readily available in many regions where rabies is endemic. This and the continuing presence and spread of rabies have increased the risk for travelers, who cannot rely on being able to receive optimal postexposure treatment in many parts of the world. Alternatives to HRIG or ERIG are not available. Travelers who leave the safe environments of tourist hotels and buses in regions of Asia, Russia, Africa, and Latin America where canine rabies is endemic may be at risk of life-threatening exposure to rabies.

Animals↗