Search PubMed⌕ Search

Biomedical subjects

A Mathur

Publications and source records attributed to A Mathur.

At least 253 records · Page 14Linked to original sources
PubMed1981

Congenital infection of mice with Japanese encephalitis virus.

Transplacental transmission of Japanese encephalitis virus (JEV) when given intraperitoneally was demonstrated in pregnant mice as shown by isolation of the virus from placenta and fetal tissues. Furthermore, JEV could be isolated from the brain, liver, and spleen of newborn mice. The effect of JEV at different periods of gestation in pregnant mice was demonstrated for the first time, and the consequences of maternal infection on fetuses and neonates were studied. JEV infection during the 1st week of gestation caused a significantly higher number of fetal and neonatal deaths (66%) than during the 3rd week of gestation (13.8%). The number of abortions, stillbirths, and neonatal deaths was higher in infected mothers than in controls. No congenital abnormalities were found in any of the newborn mice. Sera obtained from 5-week-old health mice delivered by mothers infected during the 3rd week of gestation contained JEV hemagglutination inhibiting and immunoglobulin M antibodies. The results of these preliminary experiments show the usefulness of mice as a model for further elucidation of JEV infection during pregnancy and its effects on the fetus.

Abortion, Spontaneous↗
PubMed1981

Thymus-dependent lymphocytes of dengue virus-infected mice spleens mediate suppression through prostaglandin.

Our earlier observations indicate that adoptive transfer of spleen cells obtained from dengue type 2 virus (DV)-primed mice suppressed DV antigen-specific antibody secretion as detected by Jerne PFC technique. Findings of this paper indicate that the suppression was produced by non-glass-adherent cells, macrophage-depleted (by carbonyl iron) cells and by T lymphocytes of the spleen but not by the glass-adherent cells and B lymphocytes. The activity of these cells is dependent upon production of prostaglandin as shown by abrogation of their suppressor activity by pre-treatment of cells by indomethacin or aspirin which are known to block synthesis of prostaglandins.

Animals↗
PubMed1981

Dengue virus-induced cytotoxic factor suppresses immune response of mice to sheep erythrocytes.

The present study was undertaken to investigate if the suppressed cell-mediated immune responses observed in dengue type 2 virus (DV)-infected mice could be due to the cytotoxic factor (CF) produced in the spleens of DV-infected mice. We have observed that CF given intravenously (i.v.) kills splenic cells and reduces the total cells in the spleen. Mice treated with CF have a significantly depressed immune response to sheep erythrocytes, viz. delayed-type-hypersensitivity as measured by footpad swelling reaction at 24 hr; Jerne's antibody plaque-forming cells in the spleen; and migration inhibition of spleen cells in presence of antigen. These findings are similar to those seen earlier in DV-infected mice.

Animals↗
PubMed1980

Transplacental infection with Japanese encephalitis virus.

During a widespread epidemic of Japanese encephalitis, five pregnant women affected by the illness were observed. The diagnosis of Japanese encephalitis virus (JEV) infection was established on the basis of clinical presentation, rising titers of hemagglutination-inhibiting antibody, and the presence of specific IgM antibodies. Two women aborted, two were delivered of apparently normal children, and the fate of one case is not known. From brain, liver, and placental tissues of one of the aborted fetuses, JEV was isolated. This appears to be the first report of human transplacental infection with JEV.

Adult↗
PubMed1980

Production of cytotoxic factor in the spleen of dengue virus-infected mice.

Swiss albino mice inoculated i.c. with dengue type 2 virus (DV) show presence of a factor in the spleen which is cytotoxic to the normal mice spleen cells in vitro. The cytotoxic factor is present in the homogenate as well as in the culture supernatants of the spleen cells. Maximum cytotoxic activity is present in the spleen of moribund mice on 10-11 p.i. day. No cytotoxic activity was found in the homogenates of brain, liver, heart and skeletal muscles. Sera from a few mice only had cytotoxic activity and were not complement-dependent. Cytotoxic activity in the homogenate and culture supernatant (TCF) of various spleen cell populations was screened. Cytotoxicity of glass-non-adherent cells was significantly higher. DV-infected spleen cells, depleted of macrophages by carbonyl iron treatment, had higher cytotoxic activity. B-cell-enriched fractions and the glass-adherent cells had negligible cytotoxic activity. Purified lymphocytes and the T-lymphocyte-enriched fractions had maximum cytotoxicity. Thus, a cytotoxic factor is produced by T lymphocytes of the spleen of DV-infected mice which kills normal mouse spleen cells in vitro.

Animals↗
PubMed1980

Characterization of the cytotoxic factor produced in the spleen of dengue virus-infected mice.

Data presented in the study show that the cytotoxic factor (CF) produced in the spleen of (dengue-virus) infected mice can be purified by agarose-gel electrophoresis and Sephadex G-100 gel filtration. CF is non-dialysable, heat-labile, trypsin-sensitive, unstable at acidic and alkaline pH, a macromolecular substance which sediments on ultracentrifugation and is retained by a Millipore filter of 0.45 micron size. Its approximate molecular weight is 1.15 (+/- 0.34) x 10(5) as determined by gel filtration.

Animals↗
PubMed1979

Zinc and copper levels in whole blood and plasma from patients with squamous cell carcinomas of head and neck.

Zinc in plasma and whole blood from 13 patients with squamous cell carcinoma of the head and neck was significantly decreased, and the copper:zinc ratio in the plasma was significantly higher than in healthy controls. The plasma zinc was significantly lower in patients who did not respond to therapy and who died within 12 months than in those who responded to therapy and had a remission within 12--15 months. In patients responding to therapy and alive after 12--15 months, zinc in the plasma and whole blood and the copper:zinc ratio became normal. These results suggest a potential screening and predicting value of zinc in the plasma and whole blood and the copper:zinc ratio in squamous cell carcinoma of the head and neck.

Adult↗
PubMed1979

Effect of different levels of dietary zinc on development of chemically induced oral cancer in rats.

Four-week-old female rats distributed among three experimental groups were fed a 0.23 (zinc-deficient), 0.77 (zinc-adequate) or 3.06 (zinc-supplemented) mmol zinc/kg diet and oral cancer was induced by repeated application of the water-soluble carcinogen 4-nitroquinoline N-oxide (4NQO) to the palatal mucosa. The clinical development of oral cancer differed significantly among the three groups (P less than 0.05). In rats fed the zinc-supplemented diet, the macroscopic oral cancer appeared early and the survival time was shorter than in either of the other groups. It was concluded that a zinc-supplemented diet accelerates, and a zinc-deficient diet retards the development of chemically induced oral cancer in rats.

4-Nitroquinoline-1-oxide↗
PubMed1979

Influence of zinc on onset and progression of oral carcinogenesis in rats.

Three-week-old female rats were fed 0.09 (zinc-deficient), 0.77 (zinc-adequate) or 3.98 (zinc-supplemented) mmol zinc/kg diet in three experimental groups and the palatal mucosa was painted with the water-soluble carcinogen 4-nitroquinoline N-oxide (4NQO) three times a week for 20 weeks. The zinc-supplemented diet seemed to retard the induction of carcinogenesis, whereas a low-zinc diet had the opposite effect. Once initial cellular changes had been induced the supplementary zinc seemed to accelerate their further advancement. Zinc-deficiency in animals fed a copper/zinc low-zinc diet was reflected in the plasma and liver zinc levels as well as in the copper/zinc ratio. The development of cancer was accompanied by a decrease in plasma zinc and an increase in the plasma copper/zinc ratio as well as in the liver zinc. These changes were most remarkable in the zinc-supplemented group.

4-Nitroquinoline-1-oxide↗
PubMed1979

Dengue virus-induced thymus-derived suppressor cells in the spleen of mice.

Adoptive transfer of spleen cells obtained from mice given three weekly i.p. doses of dengue type 2 virus (DV) suppressed DV antigen-specific antibody secretion as detected by the Jerne plaque technique. This suppression was produced by non-glass-adherent cells but not by glass-adherent cells. Immune spleen cells depleted of macrophages by carbonyl iron treatment had higher suppressor activity. Immune spleen cell homogenate could transfer the activity equally well. The immune spleen cells were separated into T and B lymphocytes by a nylon wool column. B lymphocytes had no suppressor activity; almost all the suppressor activity was present in T lymphocytes. Thus, macrophages and B lymphocytes had no suppressor activity; it was mediated by T lymphocytes through soluble factors.

Animals↗
PubMed1979

Variable effect on peripheral blood leucocytes during JE virus infection of man.

The peripheral blood leucocytes of twenty-four cases of Japanese encephalitis (JE) were studied and the findings were compared with those in twenty-five normal health controls of matching age and sex. In the early phases of the disease marked neutrophil leucocytosis was seen which returned to almost normal levels by the fourth week. Lymphopenia was associated with diminished T lymphocytes but the number of B lymphocytes remained within the normal range. Though the number of T lymphocytes was reduced, their function of leucocyte migration inhibition in the presence of JE virus antigen was significantly higher. The phagocytic activity of the neutrophils, as shown by the uptake of neutral red dye, was diminished but the phagocytic activity of monocytes as shown by the uptake of neutral red dye, was diminished but the phagocytic activity of monocytes as shown by the uptake of neutral red dye or ingestion of latex particles remained unaffected. HI antibodies against JE virus were significantly higher in cases of encephalitis as compared with the control group. Thus, JE virus infection in man has a variable effect on different components of the peripheral blood leucocytes.

Adolescent↗
PubMed1979

Differential depletion of T lymphocytes in the spleen of dengue virus-infected mice.

Following the i.c. inoculation of dengue type 2 virus (DV) the spleen weight of infected mice was reduced, as was the proportion of cells killed by ATS and complement (T lymphocytes) in spleen-cell suspensions. In DV-infected mice the mean haemolysin titre, 16 days after i.p. inoculation of 4 x 10(8) SRBC, was 47 compared with 406 in normal mice and spleen cells from DV-infected mice produced significantly reduced direct GVH reactivity in Parker strain (PS) infant mice. Adoptive transfer of spleen cells obtained from mice given three weeks i.p. doses of DV or a single i.c. dose, suppressed antigen-specific antibody secretion as detected by Jerne plaque technique. This suppression was abrogated by pretreating the transferred cells with ATS and complement. Thus DV selectively depletes T-lymphocyte subpopulations responsible for helper and effector functions and spares suppressor T cells in the spleen of infected mice.

Animals↗
PubMed1979

Histochemical study on the innervation of the heart of Pteropus giganteus.

Histochemical study of the innervation of the heart of the Indian flying fox Pteropus giganteus has been made using Coupland and Holmes' technique for cholinesterase. Distribution of nerve plexuses in the heart wall has been described. Nerve cells, nerve endings and various types of synapses have been reported. Specialized muscle fibres are found to contain less nerve fibres and conduction of the impulse of contraction is reported to take place through muscle fibres.

Acetylcholinesterase↗