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Biomedical subjects

T Joseph

Publications and source records attributed to T Joseph.

At least 109 records · Page 6Linked to original sources
PubMed1991

Shunt surgery for hydrocephalus in tuberculous meningitis: a long-term follow-up study.

Hydrocephalus is a common complication of tuberculous meningitis. Case studies of 114 patients with tuberculous meningitis and hydrocephalus, who underwent shunt surgery between July, 1975, and June, 1986, were reviewed to evaluate the long-term outcome and to outline a management protocol for these patients based on the results. Seven factors were studied in each case: 1) age at admission; 2) grade on admission (I to IV, classified by the authors; Grade I being the best and Grade IV being the worst); 3) duration of alteration of sensorium; 4) cerebrospinal fluid (CSF) cell content at initial examination; 5) CSF protein levels at initial examination; 6) number of shunt revisions required; and 7) the necessity for bilateral shunts. During a long-term follow-up period ranging from 6 months to 13 years (mean 45.6 months), the mortality rate was 20% for patients in Grade I; 34.7% for patients in Grade II; 51.9% for patients in Grade III; and 100% for patients in Grade IV. Only the grade at the time of admission was found to be statistically significant in determining final outcome (p less than 0.001). Based on these results, the authors advocate early shunt surgery for Grade I and II patients. For patients in Grade III, surgery may be performed either if external ventricular drainage causes an improvement in sensorium or without selection. All patients in Grade IV should undergo external ventricular drainage and only those who show a significant change in their neurological status within 24 to 48 hours of drainage, should have shunt surgery.

Adolescent↗
PubMed1991

Influence of adenosine receptor antagonists, aminophylline and caffeine, on seizure protective ability of antiepileptic drugs in rats.

Interaction of methylxanthines, aminophylline (AMP) and caffeine (CAF) on seizure protective ability of various antiepileptic drugs (AEDs), diphenylhydantoin (DPH), phenobarbitone (PB), diazepam (DZP), sodium valproate (SV) and ethosuximide (ESM) was investigated in rats. In the maximal electroshock seizure (MES) test, ED100 doses (mg/kg, ip), against hind limb tonic extension (HLTE) were DPH, 20; PB, 10; DZP, 10 and SV, 300. The interaction of AEDs with AMP (100 mg/kg, ip) reduced the seizure protection afforded by DPH, PB and DZP to 20%, while the efficacy of SV remained unimpaired. Interaction with CAF (200 mg/kg, ip) abolished the seizure protection by DPH and DZP, reduced that by PB to 20%, while the protective effect of SV was unchanged. In pentylenetetrazole (PTZ, 70 mg/kg, sc) induced seizure test, ED100 doses (mg/kg, ip) against clonic convulsions were PB, 10; DZP, 1; SV, 300 and ESM, 200. Complete seizure protection against clonic convulsions following SV or ESM was not significantly influenced by either AMP or CAF, whereas the protective effect of PB and DZP was reversed. SV and ESM showed a qualitative departure in their anti-seizure activity profiles following interaction with either AMP or CAF when compared with the other AEDs.

Aminophylline↗
PubMed1991

Effect of antiepileptic drugs valproic acid, carbamazepine and ethosuccimide on exploratory behaviour in mice.

Valproic acid in 100, 200 and 400 mg/kg doses produced a significant dose dependent decrease in exploratory behaviour, tested as number of head dips on the hole board. In the open field test, control mice entered less number of peripheral squares and more number of central squares on day 4 as compared to day 1 of the test. In the lower doses (100 and 200 mg/kg) valproic acid increased central square entries on day 1 with significant decrease by all doses on subsequent days indicating inhibition of exploratory behaviour. However, in peripheral square entry they followed the same pattern as control mice. Neither carbamazepine (10 and 20 mg/kg) nor ethosuccimide (100 and 200 mg/kg) affected exploratory behaviour in either the hole board or open field test.

Analysis of Variance↗
PubMed1990

Multicentric gliomas: two case reports and a review of the literature.

Multicentric gliomas are among the rarest of multiple intracranial neoplasms. Two biopsy proven cases are described with a review of the literature. Both cases had supratentorial and posterior fossa lesions. Computed tomography was performed in both cases, open and stereotaxic biopsy was done in one case and open biopsy of both lesions in the other case. The major problem in multicentric gliomas is the management. The two cases were managed differently based on the clinical condition and the location of the lesions.

Adult↗
PubMed1990

Effect of calcium channel blockers on experimentally induced seizures in rats.

Chemically different classes of calcium channel blockers were examined in rats for their effects on behavior, tolerability and protection against maximal electroshock seizures (MES) and pentylenetetrazol (PTZ) induced seizures. In MES test at doses (mg/kg, ip) that were devoid of side effects, felodipine, 50, afforded 100% protection, while nimodipine, 5; pimozide, 10; and thioridazine, 25, showed 50 to 66% protection. Nifedipine, 10, and diltiazem, 50, showed 30 and 66% protection respectively, but were associated with side effects. Verapamil and loperamide were ineffective against MES and PTZ induced seizures. Nimodipine, 1 mg/kg, ip, was the most potent agent and produced 100% protection against PTZ. Equieffective doses were pimozide, 25, felodipine, 50, and thioridazine, 50. The rest of the calcium channel blockers showed marginal to moderate activity against chemoshock. The data obtained suggest that some calcium channel blockers possess anticonvulsant activity and may be considered as adjuvant therapeutic agents in epileptics refractory to conventional antiepileptic medication.

Animals↗
PubMed1990

Erythrocyte and plasma cholinesterase activity in normal pregnancy.

Erythrocyte acetylcholinesterase and plasma cholinesterase was estimated in 50 normal pregnant women and 22 age matched normal non-pregnant women. Plasma cholinesterase was significantly decreased while erythrocyte cholinesterase was significantly increased during pregnancy. These changes may be related to altered haemodynamics and or other inter-related changes occurring in pregnancy.

Butyrylcholinesterase↗
PubMed1989

Primary tuberculous osteomyelitis of skull: report of two cases.

Two cases of primary tuberculous osteomyelitis of skull confirmed by appropriate laboratory investigations are described here. Primary tuberculous osteomyelitis of skull is rare. Only two cases of chronic granulomatous osteomyelitis have been described so far in the literature.

Adult↗
PubMed1989

Histopathological appraisal of carbon-dioxide laser dorsal root entry zone (DREZ) lesions in primates.

Dorsal Root Entry Zone (DREZ) thermocoagulation using radiofrequency has successfully been employed in the treatment of various deafferentation pain syndromes. The ability of surgical lasers to produce discrete lesions with precision has prompted their use in DREZ lesioning. The effects of carbon-dioxide laser induced DREZ lesions in the primate spinal cord were studied in the Bonnet monkey and the parameters necessary to produce a histologically ideal DREZ lesion were evaluated. Lesions were made with 10, 15 and 20 Watts power for pulse durations of 100 to 400 milliseconds at a constant beam spot size of 0.4 mm. It was found that histologically ideal lesions were produced with 20 Watts of power and a pulse duration of 300 milliseconds and with 15 Watts power and 400 millisecond pulse duration. The lesion lengths and widths at different parameters were also comparatively evaluated. The postulated mechanisms of deafferentation pain and the possible mode of action of DREZ lesions in management of pain are also reviewed.

Animals↗
PubMed1989

Effect of inhalation of insecticide spray on learning and memory in rats.

Acute exposure to insecticide (Baygon-spray; 5 ml/animal/5 min) inhalation in rats did not affect the learning process but produced a significant loss of memory (P less than 0.01 less than 0.001) whereas chronic exposure (one exposure per day for three weeks) produced a significant delay in learning (P less than 0.05) and memory (P less than 0.01). Acetylcholinesterase activity in brain after acute and chronic exposure declined significantly (P less than 0.01) during the learning process but returned to normal after 24 hr.

Acetylcholinesterase↗
PubMed1989

Placental transfer of paracetamol.

Paracetamol (1 g orally) was given to each of 10 healthy pregnant women undergoing normal vaginal delivery at the onset of second stage of labour. Following delivery, there was no significant difference in the serum concentration of paracetamol in the mother and the foetus (p less than 0.1), the mean value being 5.925 +/- 2.15 mg/ml and 7.875 +/- 2.22 mg/ml respectively. Paracetamol may be recommended as a safe analgesic-antipyretic during pregnancy and labour.

Acetaminophen↗
PubMed1989

Inhibition of anticonvulsant action of carbamazepine by aminophylline and caffeine in rats.

Interaction of two well known methyl xanthines, aminophylline--an antiasthmatic agent--and caffeine--commonly present in beverages, on the seizure protective ability of carbamazepine (CBZ) against electrically and chemically induced seizures in rats was investigated. Aminophylline (75 mg/kg, ip) did not alter the activity of CBZ (10 mg/kg, ip; ED100) on maximal electroshock seizures while dose dependent antagonism of CBZ efficacy was seen at 100 and 150 mg/kg, ip. Similar effects were observed with caffeine (200 and 250 mg/kg, ip). At the highest tolerated doses, aminophylline (150 mg/kg, ip) and caffeine (250 mg/kg, ip) produced antagonism of CBZ protection against pentylenetetrazole seizures. These observations support the possibility that the antagonism due to the interaction of these drugs could be related to their action at adenosine receptor sites in the brain.

Aminophylline↗
PubMed1988

Mapping antigenic domains expressed by Chlamydia trachomatis major outer membrane protein genes.

Chlamydia trachomatis is an obligate prokaryotic intracellular pathogen of humans that infects mucosal epithelial cells. Exposed domains of its major outer membrane protein (MOMP) are both serotyping and protective antigenic determinants. To identify these domains, we have cloned and epitope-mapped the genes of serovars A, C (C serogroup) and L2, B (B serogroup) with a panel of monoclonal antibodies (mAbs). Predominantly conserved regions of the genes of both serogroups are interspersed with four short variable domains (I-IV). Recombinant phage clones expressing specific MOMP antigenic determinants revealed that protective serotype-specific recognized epitopes in variable domains I and II. Protective subspecies and serogroup-specific mAbs recognized overlapping determinants in variable domain IV near the C terminus. A nonprotective species-specific mAb mapped to an invariant peptide of nine residues contained within variable domain IV. In the intact chlamydial organism of serovar B, variable domains II and IV were susceptible to proteolytic digestion, whereas both N and C termini were protected. These results suggest an arrangement of MOMP in the outer membrane in which three of the four variable domains are exposed to the outside and in which both N and C termini are presumably oriented toward the periplasmic space. This molecular analysis of MOMP antigenic determinants and their surface topology on intact chlamydiae will be useful toward the development of a recombinant subunit or synthetic chlamydial vaccine.

Amino Acid Sequence↗
PubMed1987

Protective monoclonal antibodies recognize epitopes located on the major outer membrane protein of Chlamydia trachomatis.

A panel of monoclonal antibodies (MAb) was generated against Chlamydia trachomatis serovar B, an etiologic agent of blinding trachoma. The specificities of MAb were determined by dot blot assay by using viable elementary bodies of 13 C. trachomatis serovars and two C. psittaci strains. The dot blot assay was used to identify those antigens that were unique and immunoaccessible on the chlamydial surface. MAb were identified that recognized bi-specific (serovars B and Ba) or subspecies-specific (various B complex serovars) surface-exposed antigenic determinants that were either resistant or sensitive to heat denaturation (56 degrees C, 30 min). All of the MAb recognized the major outer membrane protein as determined by either immunoblotting or radioimmunoprecipitation. MAb specific for immunoaccessible major outer membrane protein epitopes protected mice from toxic death after i.v. injection of B serovar elementary bodies and neutralized the infectivity of the organism for monkey eyes. In contrast, MAb reactive against non-immunoaccessible subspecies- or species-specific major outer membrane protein epitopes or against an immunoaccessible genus-specific epitope located on chlamydial lipopolysaccharide did not protect mice from toxic death or neutralize infectivity of the parasite for monkey eyes. These data suggest that those major outer membrane protein antigenic determinants that are serovar or serogroup specific and are accessible to antibody on the chlamydial cell surface may be useful as a recombinant subunit vaccine for trachoma.

Animals↗
PubMed1986

Hepatic subcellular distribution of short-chain beta-ketoacyl coenzyme A reductase and trans-2-enoyl coenzyme A hydratase: 25- to 50-fold stimulation of microsomal activities by the peroxisome proliferator, di-(2-ethylhexyl)phthalate.

The present study demonstrates unequivocally the existence of short-chain trans-2-enoyl coenzyme A (CoA) hydratase and beta-ketoacyl CoA reductase activities in the endoplasmic reticulum of rat liver. Subcellular fractionation indicated that all four fractions, namely, mitochondrial, peroxisomal, microsomal, and cytosolic contained significant hydratase activity when crotonyl CoA was employed as the substrate. In the untreated rat, based on marker enzymes and heat treatment, the hydratase activity, expressed as mumol/min/g liver, wet weight, in each fraction was: mitochondria, 684; peroxisomes, 108; microsomes, 36; and cytosol, 60. Following di-(2-ethylhexyl)phthalate (DEHP) treatment (2% (v/w) for 8 days), there was only a 20% increase in mitochondrial activity; in contrast, peroxisomal hydratase activity was stimulated 33-fold, while microsomal and cytosolic activities were enhanced 58- and 14-fold respectively. A portion of the cytosolic hydratase activity can be attributed to the component of the fatty acid synthase complex. Although more than 70% of the total hydratase activity was associated with the mitochondrial fraction in the untreated rat, DEHP treatment markedly altered this pattern; only 11% of the total hydratase activity was present in the mitochondrial fraction, while 49 and 29% resided in the peroxisomal and microsomal fractions, respectively. In addition, all four subcellular fractions contained the short-chain NADH-specific beta-ketoacyl CoA (acetoacetyl CoA) reductase activity. Again, in the untreated animal, reductase activity was predominant in the mitochondrial fraction; following DEHP treatment, there was marked stimulation in the peroxisomal, microsomal, and cytosolic fractions, while the activity in the mitochondrial fraction increased by only 39%. Hence, it can be concluded that both reductase and hydratase activities exist in the endoplasmic reticulum in addition to mitochondria, peroxisomes, and soluble cytoplasm.

Alcohol Oxidoreductases↗
PubMed1986

Molecular characterization of Chlamydia trachomatis and Chlamydia psittaci plasmids.

Plasmids from Chlamydia trachomatis LGV-434 (serotype L2) and Chlamydia psittaci meningopneumonitis strain Cal-10 were cloned into the BamHI and EcoRI sites of pBR322, respectively. The recombinant plasmids pCTL2 and pCPMn, each containing an entire respective chlamydial plasmid, were transformed into Escherichia coli. The sizes of the plasmids of C. trachomatis and C. psittaci were 7.3 and 6.2 kilobases, respectively. The two plasmids were found to be distinct by restriction endonuclease analysis, DNA-DNA hybridization, and electron microscopic heteroduplex analysis. However, partial homology was observed between restriction fragments of pCTL2 and pCPMn by Southern blot analysis. Polypeptide products encoded by these plasmids were synthesized in vitro by an E. coli-directed transcription-translation system and in vivo in E. coli maxicells and minicells. None of these polypeptides was immunoreactive with anti-chlamydial sera by immunoblotting or immunoprecipitation. Based on the comparative analysis data, the C. trachomatis and C. psittaci plasmids were found to share little genetic relatedness.

Chlamydia trachomatis↗