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Biomedical subjects

T J John

Publications and source records attributed to T J John.

At least 19 recordsLinked to original sources
PubMed1992

Ulnar nerve inoculation of poliovirus in bonnet monkey: a new primate model to investigate neurovirulence.

A new monkey model of poliovirus neurovirulence has been developed avoiding the currently used intraspinal injection route which traumatizes the spinal cord. Poliovirus type 1 (0.1 ml) was inoculated into the ulnar nerve of bonnet monkeys (Macaca radiata) at the right elbow. Five monkeys were inoculated with 10(7) TCID of LSc/2ab (Sabin vaccine strain); none developed any illness. Limb paralysis, clinically resembling spinal poliomyelitis in children, developed in all four monkeys given greater than or equal to 10(5) TCID50 of Mahoney strain, and in three of four monkeys given 10(4) or 10(3) TCID50. Higher functions and cranial nerves were not affected. Paralysis occurred more frequently in the lower limbs (11 limbs in seven monkeys) than in upper limbs (six limbs in seven monkeys). The incubation period, from inoculation to onset of paralysis, ranged from 5 to 12 days. Further progression of paralysis to other limbs occurred within 2 to 6 days. No illness developed in two monkeys given 10(2) TCID50 of Mahoney virus. All monkeys given LSc/2ab and those given greater than 10(2) TCID50 Mahoney virus developed humoral antibody response; however, infection of the gastrointestinal tract was detected by virus isolation from throat swabs and stools only in monkeys given Mahoney virus, but not in those given LSc/2ab. Thus, intraneural spread of Mahoney virus to the spinal cord, neurovirulence of Mahoney but not of LSc/2ab and retrograde gastrointestinal infection with Mahoney but not with LSc/2ab are the features of this experimental model.

Animals↗
PubMed1992

Evaluation of modified passive haemagglutination assay for Vi antibody estimation in Salmonella typhi infections.

A simple passive haemmagglutination assay (PHA) was developed to detect Vi antibodies, to improve the diagnosis of typhoid fever by small laboratories. The Vi capsular antigen of Salmonella typhi was extracted by alternate alcohol and acetone precipitation. Formalin fixed, sheep red blood cells treated with chromium chloride were sensitised with this Vi antigen and antibodies detected and measured by PHA. The test had a sensitivity of 83.3% among 30 cases of typhoid fever confirmed by culture. The specificity of the test was 94%, making it suitable for use in laboratories without facilities for IFAT or ELISA.

Antibodies, Bacterial↗
PubMed1992

Ultrastructural specialization of intestinal epithelium over Peyer's patches in the bonnet monkey, Macaca radiata.

The follicle associated epithelium (FAE) which separates the lymphoid follicle of Peyer's patch from the gut lumen is known to have specialized cells called M cells or "microfold" cells in man and certain animals. These cells are considered to be involved in antigen uptake and transport. Our light microscopic study of the small intestine of bonnet monkeys suggested the presence of such specialised cells in FAE. We have confirmed the presence of M cells in bonnet monkey FAE having ultrastructural features very similar to those of human M cells.

Animals↗
PubMed1992

T-lymphocyte mediated injury of beta cells in dual-aetiology diabetes mellitus in Swiss albino mouse.

Earlier we had described a dual aetiology diabetes mellitus (DADM) in mice injected with a sub-diabetogenic dose of streptozotocin (SD-SZN) and afterwards infected with coxsackie B3 virus (CBV). Further experiments were conducted to understand the mechanism of diabetogenesis. In in vitro stimulation and proliferation tests, the splenic lymphocytes (SLC) of mice given either SD-SZN or CBV infection showed lower responses to two T cell mitogens than those of control mice, indicating an immunosuppressive effect. Unexpectedly, SLC of mice given both SD-SZN and CBV showed enhanced response, indicating immunoactivation; they were not stimulated to proliferation in response to CBV antigen, indicating that the immunoactivation was not directed against CBV, but against streptozotocin or cellular elements. When mice were depleted of T cells by injecting with anti-thymocyte serum, the diabetogenic effect of SD-SZN and CBV infection was abrogated, without diminishing the replication of virus in the pancreas. Thus beta cell injury in DADM appears to be T cell-mediated.

Animals↗
PubMed1992

Microscopic anatomy of small intestine of Macaca radiata with special reference to gut associated lymphoid tissue.

The hitherto unreported microscopic anatomy of the small intestine of the bonnet monkey (M. radiata) was studied. There was a striking similarity in the general structure and cellular composition of the small intestine of the animal and that of humans. Of special interest was our observation of the occurrence of cells interspersed in the follicle associated epithelium which were morphologically similar to human M cells. These cells were pale, devoid of a brush border and frequently had lymphocytes apparently enclosed within them.

Animals↗
PubMed1992

Biological characterisation of group F streptococci causing human infections.

Fifty five strains of group F streptococci (GFS) isolated from clinical samples of 53 patients with diverse diseases, were characterised by a battery of physiological tests. Among them 37 (67%) were Streptococcus anginosus F, 14 (25%) were Strep. intermedius, two of which were mannitol positive and 4 (7%) were Strep. constellatus. Determination of minimum inhibitory concentrations of penicillin, erythromycin, ampicillin, gentamicin and cefazolin showed that despite their biochemical heterogeneity, all strains were uniformly susceptible to these antibiotics. Except for bacteraemia, other diseases due to GFS responded well to surgical drainage and/or antibiotics.

Bacteremia↗
PubMed1992

Salmonella typhi cell wall protein showing antigenic similarity to transferrin.

Antiserum to cell wall proteins of S. typhi showed immunoprecipitin lines of identity with homologous antigen, normal human serum and human transferrin. Also, anti-transferrin antibody showed immunoprecipitin band with S. typhi cell wall proteins and agglutinated S. typhi whole cells, but not Eschericia coli. It is speculated that transferrin or a transferrin-like protein present in the cell wall may play a role in iron-uptake by S. typhi.

Agglutination Tests↗
PubMed1992

Clinical and laboratory profile of AIDS in India.

The clinical features and results of laboratory investigations of the first 19 Indian patients with AIDS seen in our hospital are presented. Weight loss, fever, and diarrhea were the most common symptoms. Tuberculosis (TB) was the most common secondary infectious disease; among 13 patients, seven had only pulmonary TB, five had pulmonary and extrapulmonary TB, and one had only extrapulmonary TB. Oropharyngeal candidiasis was found in 11 patients. Other secondary infections were predominantly by virulent bacteria. Opportunistic infections other than candidiasis were infrequent; one patient had cryptococcosis, two had symptomatic cryptosporidiosis, one had noncoagulase-positive staphylococcus septicemia, and one had cytomegalovirus retinitis. Reduced lymphocyte counts (particularly of the CD4 subset), anemia, hypoalbuminemia, hyperglobulinemia, and elevated liver enzyme levels were frequent laboratory findings. Six patients are under follow-up, two are lost to follow-up, and 11 have died. Lymphocyte counts less than 500/mm3 were only seen in those patients who subsequently died. Response to antituberculosis therapy was good in several patients. Thus, the clinical profile of Indian patients with AIDS is not different from the common picture of patients of low socioeconomic and poor hygienic standards; patients presented with TB, undernutrition, and multiple infections. Therefore, a large population of patients with AIDS in India will not be recognized unless they are tested for evidence of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Immune response to purified chick embryo cell culture rabies vaccine manufactured in India.

The immunogenic efficacy of the first batch of indigenous purified chick embryo cell culture grown (PCEC) rabies virus vaccine has been measured in ten subjects. All of them were immunologically naive to rabies virus, and were given 5 doses of the vaccine in the post-exposure regime of injections on days 0, 3, 7, 14 and 30. On day 7, four subjects had developed very low levels of rabies virus neutralizing antibody, as detected and measured in the suckling mouse neutralization test. On day 14, all subjects had protective levels of antibody, which were maintained or enhanced by day 30. With the limited data presented here, the immunogenic efficacy of this batch of vaccine appeared similar to that of a batch of imported PCEC vaccine investigated earlier.

Animals↗
PubMed1992

Plasmid mediated multidrug resistance in Salmonella typhi.

Between September 1989 and February 1991, strains of S. typhi showing multiple drug resistance were isolated from blood cultures of patients with typhoid fever. A total of 283 isolates were obtained over a period of 18 months. Forty four (11%) of these isolates were resistant to chloramphenicol, ampicillin, co-trimoxazole and tetracycline, the first three being drugs currently used in treating typhoid fever. Forty of the 44 multi-resistant strains tested showed transfer of resistance 'en block' to recipient Escherichia coli K 12 (J62-2). All 44 multi-resistant strains were sensitive to ciprofloxacin and ofloxacin. Since the resistance is plasmid-mediated, the problem is likely to get aggravated.

Ampicillin Resistance↗
PubMed1991

Immune response to intradermally injected inactivated poliovirus vaccine.

Immune response to intradermal inoculation of a fractional dose of inactivated poliovirus vaccine (IPV) was measured in 8 adults and 10 children who were previously immune. A striking 4-fold to 1024-fold antibody booster response to all 3 poliovirus serotypes was found in 15 subjects and a similar response to 2 poliovirus serotypes occurred in the other 3 children. Induration and erythema of 3 mm diameter or above, indicative of a cell-mediated immune response, was seen in 12 subjects. Intradermal inoculation of IPV may be a useful technique for secondary immunisation programmes against polio and its use for primary immunisation merits investigation.

Adult↗
PubMed1991

False resistance of salmonellae to trimethoprim-sulphamethoxazole in disc diffusion method.

Apparent resistance to trimethoprim-sulphamethoxazole (TMP-SMZ) in disc diffusion method was found in 14 strains of Salmonella typhi and 2 strains of S. paratyphi A grown on Mueller Hinton agar (MHA) of one manufacturer. On MHA from another manufacturer and on diagnostic sensitivity test agar (DSTA), these 16 strains were sensitive to TMP-SMZ. The minimum inhibitory concentration of trimethoprim (TMP) assayed by agar dilution method, on DSTA medium for these 16 strains was in the range of 0.01 to 0.04 micrograms/ml. Thus, the apparent resistance was a spurious result due to the unsatisfactory quality of the batch of MHA of the first manufacturer. Presumably the medium contained thymine or its derivatives which act as antagonists to TMP and sulphonamide drugs.

Culture Media↗