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Biomedical subjects

S Nimmannitya

Publications and source records attributed to S Nimmannitya.

51 records · Page 3Linked to original sources
PubMed1980

Isolation of dengue viruses from peripheral blood leukocytes of patients with hemorrhagic fever.

Dengue viruses were isolated by a plaque technique in LLC-MK2 cells from washed peripheral blood leukocytes of patients with hemorrhagic fever. In comparison with plasma, the use of peripheral blood leukocytes permitted greater than three times the recovery rate of viruses, allowed for the isolation of strains of virus from patients with high serum levels of antibody to dengue virus, and extended the period of detectable viremia. The use of peripheral blood leukocytes was especially useful for isolation of viruses from patients with hemorrhagic fever, in whom antibody titers were generally quite high during the acute phase of the disease. This method is recommended for use by laboratories with access to the appropriate acute-phase specimens. Of the peripheral blood leukocytes, adherent monocytes appeared to be the cells most likely affected; however, involvement of atypical lymphocytes, which are commonly found in patients with hemorrhagic fever, or polymorphonuclear leukocytes could not be excluded by this study. Only a small number of infected centers could be identified by infectious-center assays, but the marked augmentation of recovery of virus with the use of peripheral blood leukocytes indicated the presence in patients of a subpopulation of cells that permit dengue virus infection.

Dengue↗
PubMed1979

Absence of leukocytes permissive to dengue 2 virus in the acute phase of dengue hemorrhagic fever.

Patients with primary dengue infection developed dengue 2 virus (D2V) permissive peripheral blood leukocytes (PBL) 2--3 weeks after infection. PBL from healthy individuals with dengue antibody were permissive to D2V in vitro, suggesting that immunologically mediated in vitro D2V permissiveness persists for a relatively long time after recovery from dengue infection. However, PBL obtained from second infection dengue hemorrhagic fever patients did not support D2V growth during the acute phase of illness but did so during convalescence. Leukocytes from dengue-immune patients with typhoid fever or non-dengue viral illness were permissive throughout both acute and convalescent phases of illness although there was tendency for increased permissiveness during convalescence. Acute phase PBL from DHF patients synthesized and secreted dengue neutralizing antibody in culture. Absence of D2V replication in these cultures was strongly, but not completely, correlated with antibody production. Other immunological mechanisms, in addition to antibody, may be operating in vitro or in vivo during acute phase dengue hemorrhagic fever to alter the permissiveness of PBL to D2V infection.

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↗
PubMed1978

The defined antigen substrate sphere system with direct immunohistoperoxidase for detection of soluble dengue antigen in sera of patients with dengue hemorrhagic fever.

The defined antigen substrate sphere system is a simple method for detecting antigen or antibody in the circulation. The technic is based on the coupling of antigen or antibody with Sepharose 4B beads that have been activated by cyanogen bromide. In this study the activated beads were exposed to dengue antigen in the serum from a patient with dengue hemorrhagic fever and then stained with antidengue antibody conjugated with horseradish peroxidase. The positive reaction showed brown beads by light microscopy, whereas the negative reaction gave colorless beads. The authors examined 134 specimens from 91 cases. The results were positive in 53.85%. The dengue antigen appeared in the sera on the day before shock or subsidence of fever. The percentages of sera containing soluble dengue antigen were greatest on the day of shock or subsidence of fever (33.33%) and on the fifth day of fever (28.07%). The highest titers of soluble dengue antigen (1:40 to 1:80) appeared in the sera of patients who had Grade III disease on the day of shock. The dengue antigen appeared most often in sera that had high titers of dengue antibody. It is postulated that this detected dengue antigen may be a part of soluble immune complexes formed during the hyperimmune stage of the immune response, and plays a significant role in the pathogenesis of dengue hemorrhagic fever and shock syndrome.

Antibodies, Viral↗
PubMed1976

Shock syndrome in primary dengue infections.

During 1974, 114 patients with dengue hemorrhagic fever were studied at the Bankok Children's Hospital. Over 40% of the patients had dengue shock syndrome. Five fatal cases were included in the study. Primary dengue infections were identified by absent or low titered antibodies in acute sera and the sequential development of IgM antibodies followed by IgG antibodies during convalescence. Three patients, aged 4,8, and 12 years, had primary dengue infections with shock. Although no convalescent sera could be tested two other patients, aged 7 to 12 years, with fatal disease also appeared to have primary infections. At the time of shock patients with primary infections had subnormal concentrations of complement factor 3. The data show that in older children dengue shock syndrome associated with complement depression can occur during primary as well as secondary infections.

Antibodies, Viral↗
PubMed1976

Immunofluorescent staining of the surfaces of lymphocytes in suspension from patients with dengue hemorrhagic fever.

Immunofluorescent staining of lymphocytes suspensions from 55 of 62 patients with dengue hemorrhagic fever was positive for dengue antigen and human beta1C/a-globulin on the surface, from the second ay before shock or subsidence of fever. The percentages of positive staining of both components gradually increased to a maximum on the day of shock or subsidence of fever. B lymphocytes increased during the course of the disease. Neither dengue antigen nor human beta1C/a-globulin was detected on the surface of the lymphocytes from normal controls or patients with other diseases. By double immunofluorescent staining with different colors of fluorochromes, antidengue antibody with fluorescein isothiocyanate and antihuman gamma -globulin or antihuman beta1C/a-globulin with lissamine rhodamine B on the same lymphocytes revealed dengue antigen appearing only on B lymphocytes. The human beta1C/a-globulin and dengue antigen were located on the surface of the same lymphocytes. The pattern of the staining by both components showed fine and coarse irregular granules over the lymphocyte surface. The fluorescent granules seemed to be on the surface but not in the intracellular vacuoles of the lymphocytes.

Alpha-Globulins↗
PubMed1975

Indirect fluorescent antibody technic for demonstration of serum antibody in dengue hemorrhagic fever cases.

One hundred eighty-three sera from two groups of children with dengue hemorrhagic fever and 37 control sera were examined for antibody against dengue virus by an indirect immunofluorescent method. When the reciprocal titer of 16 or higher was used as the diagnostic level, positive tests could be obtained in 80% of Group I and 100% of Group II sera after 3--6 days of fever. Positive tests were obtained in 100% of both groups after the first week of fever. There was no false-positive among the control sera. Preparation of the antigen is relatively easy, and the antigen may be stored for at least 3 months. The immunofluorescent method is rapid and simple, and is recommended for routine detection of serum antibody in dengue hemorrhagic fever.

Dengue↗
PubMed1975

Evaluation of the plasma kinin system in dengue hemorrhagic fever.

The role of the plasma kinin system in the pathogenesis of dengue hemorrhagic fever (DHF) ws explored by simultaneously measuring factor XLL (Hageman), prekallikrein, kallikrein inhibitors, bradykinin, and complement (C3) in the blood of Thai children with DHF and acute febrile illnesses other than dengue. Prekallikrein, factor XII, and C3 levels were significantly lower in DHF patients compared to fever control patients with the lowest mean levels found in dengue patients with shock. However, bradykinin concentrations were not elevated and mean activity levels of kallikrein inhibitors were not depressed in dengue patients. Two dengue patients first studies at least 2 days before onset of shock had falling C3 levels which were more closely related temporally to the onset of shock than were their rising levels of prekallikrein. The results fail to provide convincing evidence ofr activation of the plasma kinin system leading to free bradykinin or a significant role for bradykinin in the immunopathogenesis of DHF. By contrast, the results refocus attention on complement as a potentially important humoral mediator of the dengue shock syndrome.

Antigens, Viral↗