PubMed HealthSearch

Biomedical subjects

S Sarasombath

Publications and source records attributed to S Sarasombath.

At least 19 recordsLinked to original sources

Metabolic and immune effects of dietary arginine, glutamine and omega-3 fatty acids supplementation in immunocompromised patients.

To evaluate the nutritional, metabolic and immune effects of dietary arginine, glutamine and omega-3 fatty acids (fish oil) supplementation in immunocompromised patients, we performed a prospective study on the effect of immune formula administered to 11 severe trauma patients (average ISS = 24), 10 burn patients (average % TBSA = 48) and 5 cancer patients. Daily calorie and protein administration were based on the patient's severity (Stress factor with the range of 35-50 kcal/kg/day and 1.5-2.5 g/kg/day, respectively) Starting with half concentration liquid immune formula through nasogastric tube by continuous drip at 30 ml/h and increasing to maximum level within 4 days. The additional energy and protein requirement will be given either by parenteral or oral nutritional support. Various nutritional, metabolic, immunologic and clinical parameters were observed on day 0 (baseline), day 3, 7, and 14. Analysis was performed by paired student-t test. Initial mean serum albumin and transferrin showed mild (trauma) to moderate (burn and cancer) degree of malnutrition. Significant improvement of nutritional parameters was seen at day 7 and 14 in trauma and burn patients. Significant increase of total lymphocyte count (day 7, P < 0.01), CD4 + count (day 7, p < 0.01), CD8 + count (day 7, p < 0.0005 & day 14, p < 0.05), complement C3 (day 7, p < 0.005 day 14, p < 0.01), IgG (day 7, and 14, p < 0.0005), IgA (day 7, p < 0.0005 & day 14, p < 0.05), in all patients. C-reactive protein decreased significantly on day 7 (p < 0.0005) and day 14 (p < 0.005). 3 cases of burn wound infection, one case of UTI and one case of sepsis were observed. Two cases of hyperglycemia in burn, 3 cases of hyperbilirubinemia in trauma, 10 cases of elevated LFT (5 trauma/5 burn), and one case of hyponatremia in cancer patients were observed. Two cases of nausea, 4 cases of vomiting, 5 cases of diarrhea (< 3 times/day), 2 cases of abdominal cramp, 1 case of distension were observed. The feeding of IMMUNE FORMULA was well tolerated and significant improvement was observed in nutritional and immunologic parameters as in other immunoenhancing diets. Further clinical trials of prospective double-blind randomized design are necessary to address the so that the necessity of using immunonutrition in critically ill patients will be clarified.

Adult

Opsonophagocytosis and intracellular killing activity of neutrophils in patients with human immunodeficiency virus infection.

In this study, neutrophils isolated from asymptomatic HIV positive individuals, patients with AIDS-related complex (ARC), ARC patients receiving zidovudine (AZT) and full-blown AIDS patients were assayed for their opsonophagocytic and intracellular killing activities. Progressively decreasing opsonophagocytosis of C. albicans by neutrophils correlated with increasing severity of the disease in all groups of HIV infected individuals, as compared to neutrophils isolated from healthy controls. The intracellular killing of C. albicans by neutrophils of asymptomatic and ARC patients did not differ significantly from controls. Neutrophils of ARC patients receiving AZT and AIDS patients showed a slightly decreased killing activity in comparison to that of neutrophils from healthy controls.

Acquired Immunodeficiency Syndrome

A study of cell-mediated immune response to pancreatic antigens in patients with fibrocalculous pancreatic diabetes.

In order to investigate whether there was any association between autoimmunity to pancreatic antigens with FCPD as well as IDDM, cell-mediated immune response to pancreatic antigens was studied by lymphoproliferation assay in 7 FCPD, 17 IDDM, 33 NIDDM patients and 102 normal controls. Optimal pancreatic antigen concentrations used were 100, 150 and 200 micrograms/ml. Positive results were considered for each concentration of antigens tested, at stimulation index (SI) > (mean +/- 2 SD) SI obtained from normal age-matched controls with the use of the corresponding concentration of antigen. The one who gave positive result with any of these optimal antigen concentrations was considered to be the responder to pancreatic antigens. With this criterion, the responders were found to be 3/7 (42.9%) FCPD, 6/17 (35.3%) IDDM and 6/33 (18.2%) NIDDM patients; while there were 11 of all 102 (10.8%) normal controls.

Adolescent

Analysis of Salmonella typhi isolates from Southeast Asia by pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) revealed that multiple genetic variants of Salmonella typhi are simultaneously present in Southeast Asia and are associated with sporadic cases of typhoid fever and occasional outbreaks. Comparative analysis of PFGE patterns also suggested that considerable genetic diversity exists among S. typhi strains and that some PFGE patterns are shared between isolates obtained from Malaysia, Indonesia, and Thailand, implying movement of these strains within these regions of Southeast Asia, where they are endemic.

Asia, Southeastern

Monoclonal antibodies against protein antigens of salmonellae causing paratyphoid fever and their diagnostic application.

Hybrid clones producing monoclonal antibodies (MAbs) specific for Salmonella paratyphi A (72 clones), S. paratyphi B (9 clones) and S. paratyphi C (8 clones) were produced by using the affinity purified Salmonella protein (Bp) as immunogens. MAbs to S. paratyphi A and S. paratyphi B reacted specifically with the 52 kDa homologous flagellin protein components while those to S. paratyphi C reacted with a 61 kDa flagellin protein component. The MAbs against S. paratyphi A and S. paratyphi B were used to establish a double antibody sandwich ELISA for detection of the 52 kDa flagellin antigens in serum samples from patients with acute paratyphoid A and paratyphoid B fever. With this assay system, 6.25 ng per ml of flagellin antigens of S. paratyphi A and S. paratyphi B could be detected. However, the assay system could not detect the flagellin antigens in patients' sera. The presence of IgM antibodies to the 52 kDa antigens of S. paratyphi A and S. paratyphi B in the acute sera from paratyphoid A or paratyphoid B patients suggested that the 52 kDa protein components of both salmonellae are good immunogens for human and might be used as antigens for early diagnosis of paratyphoid A and paratyphoid B fever.

Antibodies, Monoclonal

Immunological detection of Salmonella paratyphi A in raw prawns.

A slot blot enzyme-linked immunosorbent assay, using monoclonal antibodies specific only for Salmonella paratyphi A, to detect S. paratyphi A contamination in raw prawns has been established. When artificially contaminated prawn samples were tested. S. paratyphi A contamination could be identified correctly within 20 h. No false positives from samples artificially contaminated by other microorganisms were obtained. The sensitivity was such that as few as 1 S. paratyphi A organism per g of raw prawn could be detected. Therefore, the assay constituted a promising test for the rapid and specific detection of S. paratyphi A in prawns.

Animals

Fusion protein of Salmonella typhi flagellin as antigen for diagnosis of typhoid fever.

We previously established the specific 52 kDa antigen of Salmonella typhi, detected by our monoclonal antibodies, which was a flagellin protein. Comparison of the nucleotide sequences of phase-1 flagellin of Salmonella species available through GenBank database showed high homology at both ends of the genes with lower degree of homology in the middle portion which contained the antigenically variable regions. Thus, proteins from the central regions of flagellin genes should be species specific and could be used as specific antigens for the immunodiagnostic tests. In this report, recombinant protein derived from the central region of S. typhi flagellin was produced as a fusion protein with glutathione-S-transferase. This fusion protein was used as specific S. typhi antigen for the immunodiagnostic test to detect IgM antibodies in sera using enzyme-linked immunosorbent assay. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of this test were 53.5, 98.0, 91.5, 82.1 and 92.4%, respectively.

Antibodies, Bacterial

Molecular cloning and expression of Salmonella paratyphi A 52 kDa specific protein gene.

Monoclonal antibodies (MAbs) specific to Salmonella paratyphi A have been established by our group in 1989. These MAbs were proven to be species-specific for 52 kDa protein of S. paratyphi A but the nature of this protein is unknown. However, our group have proved that the 52 kDa protein which is specific to S. typhi was flagellin. This present study has characterized the 52 kDa protein of S. paratyphi A and identified its encoded gene. The plasmid containing the specific 52 kDa antigen gene was cloned from the S. paratyphi A genome, herein designated pSKA-4. Partial nucleotide sequences from this clone was analysed by computer program and found to be phase 1-a flagellin gene of S. paratyphi A. In addition, the nucleotide sequence analysis from such clone also showed that the structural gene for phase 1 flagellin has amino acid sequences conserved at the terminal whereas the central region is variable among Salmonella spp. Therefore, the central portion of flagellin which highly polymorphic in amino acid sequences would be the most specific to S. paratyphi A, thus, should be used as specific antigen for developing specific diagnosis of S. paratyphi A infection. Using the PCR technique, an expression plasmid containing the antigen gene producing only the variable region in the central portion of flagellin from S. paratyphi A, namely pSKA-7, has been established. The recombinant protein produced by the established plasmid has a MW 33.5 kDa as detected by immunoblotting using specific MAbs. Further study by using this specific flagellin protein for immunodiagnosis of S. paratyphi A infection is being carried out in our laboratory.

Animals

Production of monoclonal antibodies to Vi polysaccharide antigen of Salmonella typhi.

Twenty-four Vi antigen-specific monoclonal antibodies were produced in this study. The MAbs were found to be highly specific to Vi possessing bacteria. Selected MAbs were used in a direct agglutination assay for rapid identification of S. typhi in primary bacterial culture and also used to develop an assay to detect Vi antigen in clinical specimens. The result showed that they could not detect the antigen in urine and serum from acute patients even they could detect as low as 0.02 micrograms/ml of Vi antigen added in normal urine. The study has shown that these MAbs are very useful for rapid identification of S. typhi in primary bacterial culture and they can replace polyclonal anti-Vi antibodies which have been used routinely in bacteriological laboratories.

Agglutination Tests

Molecular cloning and expression of Salmonella typhi flagellin: characterization of 52 kDa specific antigen of S. typhi.

We previously reported monoclonal antibodies (MAbs) specific to S. typhi 52 kDa antigen which do not cross react with related protein antigens from 11 bacteria causing enteric fever and enteric fever-like illness. Using the combination of these specific MAbs and recombinant DNA technology, expression plasmids containing the antigen gene producing substantial amount of the S. typhi protein antigen have been established. Plasmid pSKM-T7 containing the specific 52 kDa antigen gene was cloned and the antigen expressed was detectable by immunoblotting using specific mAbs. The complete nucleotide sequence of this gene was compared with other bacterial sequences and found to be highly homologous with the flagellin gene H1-d of S. muenchen except in the hypervariable region in the central portion. The specific 52 kDa antigen of S. typhi detected by our MAbs is thus a flagellin.

Antibodies, Monoclonal

Presence of autoimmunity to pancreatic antigens in a patient with fibrocalculous pancreatic diabetes.

A case of fibrocalculous pancreatic diabetes (FCPD) is reported for which antibody and cellular immune characteristics were determined. The patient, a Thai woman, had serum islet cell antibodies (ICA) that were detected by both immunoperoxidase staining and an indirect enzyme-linked immunosorbent assay (ELISA). Serum anti-human insulin antibodies were negative by a displacement ELISA. Lymphoproliferation assay against pancreatic antigen prepared from a blood group O cadaveric donor was positive. Increased CD8+ lymphocytes were observed using direct immunofluorescence staining and flow cytometry. CD4+ T lymphocytes, B lymphocytes and NK cells were within normal levels. These findings provide evidence for autoimmunity to pancreatic antigens in a patient with fibrocalculous pancreatic diabetes.

Adult

Production and characterization of monoclonal antibodies against the excretory-secretory antigen of the liver fluke (Opisthorchis viverrini).

Monoclonal antibodies (MoAb) were produced against a major soluble metabolic product (excretory-secretory, ES) of Opisthorchis viverrini. The latter was obtained in a form of spent culture medium in which the adult flukes had been maintained in vitro. The MoAb produced were exclusively associated with either IgG or IgM isotypes. When screened against a panel of parasite antigens by indirect ELISA, these MoAb exhibited three patterns of reactivity. Approximately 50% of the MoAb were highly specific for O. viverrini and another 25% cross-reacted only with Clonorchis sinensis. The remaining 25% cross-reacted extensively with other parasites. Results from radioimmunoprecipitation and immunoblotting experiments showed all MoAb to react with the 89-kDa glycoprotein. By indirect immunofluorescence, these MoAb reacted almost exclusively with the tegumental surface, tegumental cells, cecum and developing miracidium. Different lines of evidence suggest that these MoAb reacted with different epitopes on the same 89-kDa polypeptide carrier.

Animals

Studies on the 52 kDa antigen of Salmonella typhi: physicochemical stability, purification by affinity chromatography and immunochemical specificity.

The 52 kDa specific protein antigen of Salmonella typhi, as identified by monoclonal antibodies (Ekpo et al. 1990) has been studied with respect to its physicochemical stability, purification by affinity chromatography and immunochemical specificity. It was found that the 52 kDa protein was degraded into smaller antigenic fragments of MW 30-51 kDa when treated with acetone, ethanol, sodium thiocyanate, 0.3M sodium chloride and Veronal and Tris buffers. The exact chemical nature of the degradation of the protein under these conditions is not known but digestion by conventional proteases and dissociation of the non-covalent subunit type have been ruled out. It is proposed that the degradation may be the result of yet unidentified enzyme(s) which become activated by various physical or chemical treatments. Affinity chromatography using a specific monoclonal antibody has been carried out in an attempt to purify the 52 kDa protein. The binding of S. typhi protein to the column was saturable at 65.6 microgram protein/ml gel. The amount of S. typhi protein adsorbed on the column was 0.51% of the total sonicated cell protein. SDS-PAGE of the immunoadsorbent purified protein revealed bands at Mr 15-58 kDa, indicating that the protein obtained had been severely degraded. However, Western blot of the purified protein stained with a specific monoclonal antibody and with rabbit polyclonal antibody against S. typhi showed striking similarity, indicating that the protein obtained was close to immunochemical purity. The 52 kDa protein purified by affinity adsorbent was used as an antigen for the detection of specific IgM in sera of patients. It was shown that sera of patients infected with S. typhi as well as those infected with other bacteria, contained specific IgM against the 52 kDa protein. Thus, it appears that the 52 kDa protein contains species specific as well as cross-reacting epitopes. The possible development of specific diagnosis of S. typhi based on the present experimental results in discussed.

Antibodies, Monoclonal

Monoclonal antibodies to 52-kilodalton protein of Salmonella typhi.

Ten monoclonal antibodies (6 immunoglobulin G1 kappa [IgG1 kappa] and 4 IgG2b kappa) from six hybrid clones specific for Salmonella typhi antigen were produced by immunizing BALB/cJ mice with affinity-purified S. typhi proteins (Bp). The latter were prepared by passing crude S. typhi Bp through an affinity column made from Sepharose conjugated to IgG antibodies against partially purified S. typhi Bp. The eluent was subsequently used as the immunogen for the production of monoclonal antibody. All 10 monoclonal antibodies reacted specifically with a 52-kilodalton (kDa) protein of S. typhi and were species specific. The presence of IgM antibody to the 52-kDa antigen in the sera of a majority of patients with acute typhoid fever suggested that this 52-kDa protein is also a good immunogen for humans. The potential usefulness of this antigen in the early diagnosis of typhoid fever is discussed.

Acute-Phase Proteins

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

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