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Biomedical subjects

S Sarasombath

Publications and source records attributed to S Sarasombath.

At least 37 records · Page 2Linked to original sources
PubMed1988

Methylprednisolone therapy in aplastic anaemia: correlation of in vitro tests and lymphocyte subsets with clinical response.

20 patients with aplastic anaemia were treated with methylprednisolone 1 g/d for 3 d followed by prednisolone 60 mg on alternate days. At 3 months after therapy, 7 of 20 patients (35%) showed recovery, 2 had died and 11 were non-responders. Only newly diagnosed patients were responders. Results of in vitro tests were correlated with clinical response. The first test was designed to determine whether removing various subpopulation of cells would increase the numbers of progenitor cells. In the second test blood cells were collected at 1 month after starting treatment and assayed for progenitor cells. Data from both tests did not correlate with the response to therapy. Lymphocyte subsets were measured in the blood before and at 1 month after treatment. The absolute numbers of OKT3+, OKT4+ and OKT8+ cells were significantly decreased compared to the normal population. The number of HNK1+ cells was also decreased but no significant difference was observed. Responders had a higher number of HNK1+ cells compared to non-responders. No significant differences of OKT3+, OKT4+ and OKT8+ cells among responders and non-responders were observed. Therefore a high number of HNK1+ cells prior to therapy may identify patients responding to the treatment.

Adolescent↗
PubMed1988

Characterization of monoclonal antibodies to protein antigen of Salmonella typhi.

Two monoclonal antibodies were produced against protein antigens of Salmonella typhi. One of the antibodies (STP14) belongs to the immunoglobulin G1K subclass, and the other (STP13) was assigned to the immunoglobulin G2a(kappa) subclass. Both antibodies could recognize the 34.0-kilodalton protein antigen from S. typhi. The specificity of these antibodies was tested by immunoblotting with a panel of crude protein antigens from 12 bacteria causing enteric fever and enteric fever-like illness: S. typhi, S. paratyphi A, S. paratyphi B, S. paratyphi C, S. choleraesuis, S. enteritidis, S. krefeld, S. panama, S. typhimurium, Escherichia coli, Pseudomonas pseudomallei, and Yersinia enterocolitica. In a modified double-antibody sandwich enzyme-linked immunosorbent assay they could detect the protein antigen at ca. 0.6 microgram/ml. These monoclonal antibodies should be of great value in the diagnostic test for detecting S. typhi antigen in samples of bodily fluids isolated from patients with typhoid fever and in studies of the chemical structure and other immunological properties of this 34.0-kilodalton protein.

Antibodies, Bacterial↗
PubMed1988

Natural killer cells in dengue hemorrhagic fever/dengue shock syndrome.

Natural killer (NK) cell activity against K-562 target cells and HNK-1+ cell levels were serially determined in peripheral blood of 62 Thai children with dengue hemorrhagic fever/dengue shock syndrome aged 4-12 years and 59 age-matched normal controls. The studies were performed on febrile stage, 1st and 2nd day of subsidence of fever (shock stage), 3rd and 4th day of subsidence of fever (early convalescent stage) and once again on the late convalescent stage (approximately 14-18 days after subsidence of fever). The study revealed that during the course of disease the NK cell activity was not changed significantly from the normal controls. In contrast, the levels of HNK-1+ cells, which exhibited almost all NK and killer cell functional activities, were significantly decreased in the febrile and the shock stages and were normal in the early and late convalescent stages. The NK cell activity, on the per-cell basis, was significantly increased in the early disease stage when compared to that of the later period of the disease and of the normal controls. The study also revealed that patients with grade III of disease severity exhibited significantly more NK cell functional activities per cell than grade II on febrile stage and the first day of shock. These results suggest that natural killer cells were active in defense against dengue viral infection and might play some role in the pathogenesis of dengue hemorrhagic fever/dengue shock syndrome. Their functions might also determine the severity of the disease.

Child↗
PubMed1988

Kinetics of lymphocyte subpopulations in dengue hemorrhagic fever/dengue shock syndrome.

A kinetic study of lymphocyte subpopulations was performed in 61 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) patients aged 8 months to 12 years and in 59 age-matched normal controls. There were 36 patients in grade 2 and 25 patients in grade 3 of the disease severity. The studies were performed on febrile stage, the day of subsidence of fever or shock stage, 3 subsequent days after subsidence of fever or shock, and once on the recovery stage (approximately 14-18 days after subsidence of fever or shock). The study revealed that the absolute total lymphocytes, CD3+, CD4+, CD8+ and HNK-1+ cells were decreased on febrile stage and their lowest values were noted on the first day of subsidence of fever or shock, while B1+ cells were in the normal range. Thereafter, all lymphocyte subpopulations were increased. The total lymphocytes, B1+ and CD8+ cells were rapidly increased and were above normal value on day 2 after subsidence of fever or shock (early convalescence), then gradually declined to the normal range. In contrast, CD3+, CD4+ and HNK-1+ cells were increased gradually and reached their normal values on day 2 after subsidence of fever or shock. The T4:T8 ratio began to reverse on the day of subsidence of fever or shock, reached its peak on day 2 after shock and returned to normal ratio rapidly thereafter. Thus, the absolute lymphopenia on the day of shock was due to the decrement or T cells (both CD4+ and CD8+ cells) and HNK-1+ cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1987

Enzyme-linked immunosorbent assay for detection of Salmonella typhi protein antigen.

A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was designed for the detection of Salmonella typhi protein antigen. The optimal concentration of antibody for coating the plate was found to be 50 micrograms/ml. The optimum conditions for antibody coating and antigen and conjugate incubation were 37 degrees C for 3 h, 37 degrees C for 2 h, and 4 degrees C overnight, respectively. The enzyme-substrate reaction was allowed to take place at 30 degrees C for 1 h. The established ELISA was found to be reproducible, with an inter-run coefficient of variation of less than 12% for the detection of an S. typhi protein antigen concentration of 0.5 to 50 micrograms/ml. The minimal detectable level of the antigen was 0.5 micrograms/ml. Cross-reactions were observed with the high level (50 micrograms/ml) of protein antigens obtained from Salmonella typhimurium, Escherichia coli, Salmonella paratyphi A, and Salmonella enteritidis. The ELISA established was used for the detection of S. typhi protein antigen in serum from 62 patients with typhoid, 30 patients with clinically diagnosed typhoid fever, 21 patients with paratyphoid, 17 patients with pyrexia caused by other bacteria, and 160 normal, healthy individuals. It was found that the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of this assay were 83.87, 89.04, 87.93, 67.53, and 95.31%, respectively.

Antigens, Bacterial↗
PubMed1987

Systemic and intestinal immunities after natural typhoid infection.

A 2-year study of systemic and intestinal immunity to Salmonella typhi was performed in 14 patients who were suffering from typhoid fever in an attempt to extrapolate the mechanism of immune responses in this disease. The methods employed were the leukocyte migration inhibition agarose test for the measurement of systemic cell-mediated immunity. The systemic immunoglobulin G (IgG) and IgM that were specific to S. typhi and anti-O and anti-H agglutinins were measured by indirect enzyme-linked immunosorbent assay (ELISA) and the Widal test, respectively. The immunobead ELISA was used to measure total secretory IgA (SIgA), and indirect ELISA was used to measure SIgA that was specific to S. typhi in the intestinal lavage fluid. The results revealed that the patients developed various types of immune response to S. typhi that had various magnitudes and durations. After the onset of illness, the cell-mediated immunity persisted for 16 weeks; IgG, IgM, and anti-O and anti-H agglutinin persisted for 2 years, 16 weeks, 16 weeks, and 36 weeks, respectively. SIgA can persist in the gut for about 48 weeks. Thus, the immunities as a whole can barely persist beyond 1 year after the onset of illness, unless there are persistent booster stimulations by S. typhi bacilli that exist in the environment, and then the immunities may be lifelong.

Adolescent↗
PubMed1987

Detection of Salmonella typhi protein antigen in serum and urine: a value for diagnosis of typhoid fever in an endemic area.

Using haemoculture as the gold standard, a double antibody sandwich ELISA for the detection of Salmonella typhi Barber protein antigen (BP) was compared with the Widal test. Specimens used were serum and urine obtained from normal healthy individuals and from patients with typhoid fever, paratyphoid fever, pyrexia caused by other bacteria and pyrexia with negative haemoculture. The ELISA for antigenuria gave a significantly higher sensitivity, specificity, accuracy and positive predictive value than the Widal test (p less than 0.05). The ELISA for antigenaemia gave a significantly higher sensitivity and positive predictive value only. All other values were not significantly different. The timing of specimen collection was critical for sensitivity in the ELISA for antigenaemia and antigenuria, and the best results could be obtained by carrying out both assays simultaneously. The clearance of BP from serum into urine occurred around 16 days after the onset of fever in one patient. In two patients, BP could be detected in sera up to 3 weeks after the onset of fever. In two patients, serum BP could still be detected although haemoculture was negative.

Antigens, Bacterial↗
PubMed1987

Gel-filtration chromatography of Salmonella protein antigens and their implication in immunodiagnosis.

Crude Barber protein (Bp) antigens were prepared from Salmonella typhi, S. krefeld and S. derby by an original method that has been described previously. These antigens were subjected to gel-filtration chromatography using Sephadex G-200. A sharp peak that eluted together with the void volume was thus separated from a broad second peak that eluted from the column at positions equivalent to 118,000 to 12,000 daltons. The proteins eluted in the latter peak were arbitrarily divided into 5 fractions and, together with the first peak, subjected to polyacrylamide gel electrophoresis and immunoprecipitation with both homologous and heterologous rabbit antisera. The extent of immunological cross reactivities was determined by enzyme-linked immunosorbent assay. The preliminary results obtained by this technique showed species-specific protein antigens to have molecular weights ranging between 36,000 and 68,000 daltons.

Animals↗
PubMed1987

Systemic and intestinal immunities after different typhoid vaccinations.

The comparative studies of systemic and intestinal immunities to S. typhi were performed in 29 healthy volunteers during 2 years after receiving oral vaccination with attenuated S. typhi Ty21a in gelatin capsule, parenteral vaccination with acetone inactivated or heat inactivated-phenol preserved S. typhi Ty2. The methods used were immunobead ELISA for total secretory IgA and indirect ELISA for specific secretory IgA in the intestinal lavage fluid. The specific systemic IgG, IgM and anti-O, anti-H agglutinins were measured by indirect ELISA and Widal test respectively. The leukocyte migration inhibition test was used for the measurement of systemic cell mediated immunity. The results indicate that the oral S. typhi Ty21a stimulated intestinal immunity better than both parenteral vaccines but evoked less systemic antibody response. The stimulation of systemic cell-mediated immunity by the live attenuated and acetone inactivated vaccine was comparable while stimulation by heat inactivated-phenol preserved vaccine was less pronounced. The same studies were performed in 26 healthy volunteers during 6 months following different doses of oral vaccination with S. typhi Ty21a in enteric-coated capsule. The results suggest that the stimulation of intestinal and systemic immunities by this vaccine is dosage dependent. Three doses of vaccine provide better stimulation than two doses and one dose, respectively.

Administration, Oral↗