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Biomedical subjects

N Bhamarapravati

Publications and source records attributed to N Bhamarapravati.

At least 73 records · Page 4Linked to original sources
PubMed1981

Quantitation of dengue precipitating antibody by inhibition countercurrent immunoelectrophoresis.

The inhibition countercurrent immunoelectrophoresis test was employed to detect dengue virus antibody in patients' sera. Anti-dengue type 2 titers determined by inhibition countercurrent immunoelectrophoresis correlated well with hemagglutination inhibition titers. In secondary cases, more than fourfold increases in precipitating antibodies were observed. The control sera were negative except for sera from a few patients with systemic lupus erythematosus, which showed low titers. Simultaneous detection of dengue virus antigen and antibody in sera collected during the acute phase could confirm at least 90% of cases. This method is recommended as a routine technique to quantitate antibody in sera from suspected cases of dengue hemorrhagic fever.

Antibodies, Viral↗
PubMed1981

Histocompatibility antigens and dengue hemorrhagic fever.

Histocompatibility antigen (HLA) A and B typing on lymphocytes from 87 unrelated Thai children who had been hospitalized with dengue shock syndrome (DSS) and/or dengue hemorrhagic fever (DHF) was compared with that found in 138 controls who had not been hospitalized with clinical dengue infection. These data are presented as descriptive information; however, a statistical analysis was performed to identify potentially important relationships for future study. Several deviations (P less than 0.05) were detected in the distribution of four HLA-A and three HLA-B antigens. The prevalence of one HLA-A antigen and two HLA-B antigens appeared to relate to the development of DSS, with a positive association seen for HLA-A2 and HLA-B blank and a negative relationship for HLA-B13. These findings require confirmation, but they do suggest that genetic susceptibility may be important in the development of DHF/DSS and indicate that further broader studies of genetic markers might be rewarding.

Child↗
PubMed1980

Electron microscopic study of the vascular endothelial cell in dengue hemorrhagic fever.

Electron microscopic studies were performed from skin biopsies taken from patients aged between 1-14 years suffering from dengue hemorrhagic fever. Several capillaries showed marked distortion, but severely damaged vessels were not observed in this study. In many cases, however, swelling of a single endothelial cell was noted. This was characterized by a rarefaction of the cytoplasm and formation of the plasma membrane which extruded into lumen and narrowed it. In many vessels examined, these blebs became detached from the endothelium and were found free within the capillary lumen. Myelin figures were often observed in such vessels. Mitochondria in the swollen endothelial cells often showed contraction of the inner compartments. Although, most of the endothelial junctional complexes were intact, several gap formations, in vascular wall were observed. Vacuolation of the cytoplasm and increase in the pinocytotic vesicles in endothelial cells which represented transport of plasma fluids from the capillary to the pericapillary space were quite evident. In no case did there seem to be marked alternation of the basement membrane of the capillary. The morphological alterations observed in this study only suggest the non-specific response of the dermal capillaries. These findings were similar to the findings observed in capillaries after being subjected to heat or ischemia.

Adolescent↗
PubMed1979

Rapid detection of dengue viral antigens by counterimmunoelectrophoresis.

Counterimmunoelectrophoresis (CIE) was applied to detect dengue viral antigen in an experimental system and in clinical situations. In the experimental system, all four types of dengue viruses (dengue 1 to 4) were detected when tested against rabbit hyperimmune sera. With homologous antibody, antigen could be detected when hemagglutinating titer was as low as 1:20. In clinical situations, 67% of the sera of patients with dengue hemorrhagic fever collected on day 4 after onset of fever were positive by CIE. Antigens could be detected most frequently from day 4 to day 7. In 11% of the cases, antigens were found to persist as long as 38 days. Validity of this detection was confirmed in some cases by immunologic methods. Virtues of CIE are its technical simplicity, rapidity, and economy.

Antigens, Viral↗
PubMed1979

The HLA antigens and leprosy in Thailand.

HLA-A and -B locus antigens were determined in 170 unrelated patients with leprosy and 100 healthy controls. There were no statistically significant deviations from expected antigen distribution in patients with any of the various forms of leprosy, though the number of patients studied is relatively small. There were some interesting trends, particularly a possible decrease in the number of tuberculoid patients with A9, and an increase in the proportions of lepromatous patients with B18 and B40. Limited evidence of a genetically controlled pre-disposition to the clinical manifestations of leprosy suggests that further studies with extended typing should be carried out on the HLA haplotype segregation in informative leprosy families. These should provide a clearer indication of the relevance of the HLA (including DR) and possibly of other non-HLA loci to the possible mechanism(s) of disease susceptibility.

Adolescent↗
PubMed1979

Immunofluorescence study of skin rash in patients with dengue hemorrhagic fever.

Fifty-three skin biopsy specimens obtained from the cutaneous rashes of patients who had dengue hemorrhagic fever (DHF) were studied by immunofluorescence technique. Six specimens showed deposits of IgM, beta 1 C-globulin, dengue antigen, and fibrinogen during the first week of fever. Some but not all of these components (IgM, beta 1 C, dengue antigen) were demonstrated in 29 specimens. Twenty-three of them yielded negative results. Granular deposits of IgM and beta 1 C appeared in the blood vessel walls of dermal papillae. Dengue antigen was seen in mononuclear cells that were closely infiltrated around the blood vessel wall in dermal papillae. Fibrinogen was located within or about the blood vessels. The findings suggest that the cutaneous rashes occurring in DHF are caused by an immunopathologic process.

Antigens, Viral↗
PubMed1979

Immunopathological studies of Plasmodium berghei infected mice: (effect of carbon particles).

An attempt was made to block the role of the macrophages in the immune response by saturating them with carbon particles. The experiment was performed on Swiss albino female mice injected intraperitoneally with 10(5) P. berghei berghei. These mice were injected with carbon particles of 20 mgs on the day before the inoculation and again 10 mgs on day 4 and day 9 after the inoculation. The degree of parasitaemia was slightly higher throughout the experiment in the infected mice treated with carbon than in those untreated. By direct immunofluorescent method the free floating form of malaria antigen was detected in the infected organs (liver, kidney and spleen) on day 3 of infection onwards. The antigen was more intense in the carbon treated mice than in the untreated ones. The granular form of the antigen in the walls of glomerular capillaries of the kidney, in the Kupffer cells of the liver and in the reticulo-endothelial cells of the spleen, the malarial antibody and the immune complex (malaria antigen, antibody and mouse beta 1 C globulin) in the kidney were detected later on (day 11).

Animals↗
PubMed1979

Demonstration of dengue antibody complexes on the surface of platelets from patients with dengue hemorrhagic fever.

By the direct immunofluorescent technic, dengue antigen, human immunoglobulins, and beta 1C globulin were detectable on the surfaces of platelet suspensions from 48% of patients with dengue hemorrhagic fever. The percentages of positive-staining platelets were not related to the severity of thrombocytopenia, which was marked on the day after the patient developed shock or subsidence of fever. It is suggested that an immunologic mechanism is one of the factors associated with the thrombocytopenia caused by increased platelet destruction.

Adolescent↗
PubMed1979

Plasmodium berghei--infected mice. Focal glomerulonephritis in hyperimmune state.

Twenty-one male Swiss albino mice were injected intraperitoneally with 2 x 10(5) Plasmodium berghei berghei-infected cells. Twenty-four mice were used as a noninfected control group. On the tenth day after infection, three mice were killed and the remainder were treated with chloroquine phosphate (0.025% solution) given orally. The dosage was subsequently adjusted to keep the parasitemia below 5%. Eighteen of the controls received the same chloroquine dosage. Diffuse proliferative glomerulonephritis was seen from day 10 of infection up to two months after treatment. Granular deposits of immune complex were seen in all glomeruli. At the end of third month and thereafter, all experimental mice were in a hyperimmune state, and the kidneys showed the characteristic of focal glomerulonephritis resembling some types of human focal glomerulonephritis.

Animals↗
PubMed1978

Ultrastructural studies on dengue virus infection of human lymphoblasts.

Ultrastructural studies of dengue-2 virus-infected lymphoblastoid Raji cells showed that the virus induced an increase in the size of the rough endoplasmic reticula (RER) and that the replication of the virus was confined to the cisternae of these RER. The proliferating RER formed cytoplasmic inclusions that could be seen by light microscopy. This observation could be used as evidence of a cytopathogenic effect of dengue virus on infected Rajii cells in routine cultures. Accumulation of virions in the infected cells was minimal in comparison with other cell systems, however. Sporadic clusters of mature virions were often seen on the plasma membrane. These extracellular virions were distributed adjacent to the virus-bearing RER and were presumably released virions. Vertical transmission of the virus was evident in mitotic lymphoblasts. The replication pattern of dengue virus in lymphoblastoid cells suggests that efforts should be made to determine whether blast-transformed lymphocytes, numerous in secondary dengue infections, support dengue virus replication in vivo.

Cell Line↗
PubMed1978

Liver changes in hamsters infected with a liver fluke of man, Opisthorchis viverrini.

Thirty male Syrian golden hamsters were each infected with 100 metacercariae of Opisthorchis viverrini. The hamsters were killed at 3, 7, 15, 30, 154 days of infection. The early pathological changes consisted of an acute inflammatory reaction involving the bile ducts of the second order and the portal connective tissue, especially the large veins, as well as focal coagulation necrosis of the liver lobules. As the flukes developed into adults they induced hyperplasia and adenomatous formations of the bile duct epithelium. There was also a granulomatous response to the adult flukes and eggs. Resolution of the granulomas led to periductal and portal scarring. These findings suggest that immunopathologic mechanisms may be important in the pathogenesis of liver fluke disease.

Animals↗
PubMed1978

Influence of dietary protein and vitamin B12 on the toxicity and carcinogenicity of aflatoxins in rat liver.

The influence of dietary protein content and dietary vitamin B12 supplement on the hepatotoxicity and carcinogenicity of aflatoxin in rat liver was studied. In animals fed a low-protein diet, aflatoxin induced extensive toxic and carcinogenic effects. Cirrhosis was significantly prevented to a certain level by vitamin B12 administration, but the incidence of cholangiofibrosis and hyperplastic nodules was unchanged. No toxic effect was observed in animals receiving high-protein diet with no vitamin B12 supplement in this study (33 weeks). Only one rat bearing a hepatoma was observed in this group. However, hepatoma and hyperplastic nodules were found in the group receiving high-protein diet plus vitamin B12. Cholangiofibrosis and cirrhosis were not observed in the high-protein group regardless of vitamin B12 administration.

Aflatoxins↗