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Biomedical subjects

J Mohan

Publications and source records attributed to J Mohan.

At least 55 records · Page 3Linked to original sources
PubMed1983

Location--allocation models, social science and health service planning: an example from North East England.

This paper reports on a project carried out by the author to assess strategies for hospital location in the Durham Health District, England. This project was set up in the context of a dispute on hospital strategy between the relevant Regional and Area Health Authorities and so the development of the dispute is outlined. This is followed by a summary of the work carried out in which some reservations about the techniques employed are put forward. The subsequent debates between the Regional and Area Health Authorities are also discussed. The paper concludes by raising more general issues concerning the role of the state and the use of knowledge in planning.

Catchment Area, Health↗
PubMed1980

Vascular smooth muscle response to fibrinogen degradation products and 5-hydroxytryptamine: possible role in cerebral vasospasm in man.

1 Experiments were performed to determine the effects of fibrin(ogen) degradation products on the following in vitro vascular preparations: rabbit aortic strip, rat aortic strip and human basilar arterial strip. 2 Citrated plasma and streptokinase were incubated at 37 degrees C to produce a crude preparation of fibrinogen degradation products and 0.1 ml aliquots were removed at various time intervals. These samples were tested for intrinsic activity and possible interactions with EC50 and threshold concentrations of 5-hydroxytryptamine on the vascular preparations. 3 Enhancement of the responses obtained by both concentrations of 5-hydroxytryptamine was produced by samples taken throughout the streptokinase incubation period, the maximum effect being seen at 90 min. 4 The 90 min incubate produced volume-dependent (25-400 microliters) potentiations of the responses developed in the three vascular preparations to the EC50 and threshold concentrations of 5-hydroxytryptamine. 5 It is suggested that fibrin(ogen) degradation products may be involved in the intense vasoconstriction of the cerebral arteries following subarachnoid haemorrhage.

Animals↗
PubMed1977

Effects of (+) and (-)-propranolol on the responses of the human isolated basilar artery to cerebrospinal fluid obtained from patients with subarachnoid haemorrhage and cerebral arterial spasm.

1. The human isolated basilar artery has been used as a model to investigate the aetiology of cerebral arterial spasm associated with rupture of intracranial aneurysms. 2. The isolated artery is contracted by 5-hydroxytryptamine, noradrenaline, six prostaglandins and cerebrospinal fluid from patients with ruptured aneurysms and cerebral arterial spasm. 3. These contractions are reversed by (+/-)--, (+)-- and (--)-propranolol in concentrations known to produce local anaesthetic effects on isolated frog sciatic nerve; the (+) isomer was 2.5 to 10 times more potent (-)-propranolol in antagonising all contractions. 4. As the two isomers are known to have similar local anaesthetic potency but (-)-propranolol has greater beta-adrenoreceptor blocking effects we conclude that the antagonistic effects described do not involve beta-adrenoreceptor blockade. 5. The data indicate that propranolol may be of clinical use in reversing cerebral arterial spasm.

Basilar Artery↗
PubMed1976

Ribosomal DNA and its expression in Drosophila melanogaster during growth and development.

Ribosomal DNA content has been determined in several adult and larval tissues of Drosophila melanogaster. Underreplication of rRNA genes was observed in polytenic salivary glands of larvae. On the contrary, polytenic/polyploid ovaries showed no decrease in rDNA. It is concluded that polyteny is not necessarily associated with underreplication of rDNA. No other tissue examined displayed any change in rDNA redundancy. Third-instar-larvae showed a decrease in rDNA amount which might be partly accounted for by underreplication of rDNA in salivary glands. No such decrease was seen in pupae. Bobbed genotypes were essentially similar to wild type in all tissues except salivary glands. In this case, it was found that the extent of underreplication is less in bobbed as compared to wild genotypes. Ribosomal DNA activity was examined in various tissues of Drosophila melanogaster. The rates of rRNA synthesis vary greatly between various tissues. It is concluded that a control at the level of gene activity operates as differences in the amount of precursor rRNA synthesized can be observed both in flies of varying rDNA contents as well as in various tissues of the same genotype.

Animals↗
PubMed1976

Malignant spread of haemangioblastoma: report on two cases.

Two cases are described in which, after successful removal of a cerebellar haemangioblastoma followed by several years of freedom from symptoms, there developed a progressive spinal cord compression, leading to death. At necropsy the spinal cords in both cases and the brainstem in one case, were irregularly plastered with haemangioblastoma. Although there was no doubt that malignant spread had occurred from one or more primary tumours, the histology of the tumour tissue was in no way different from that of conventional haemangioblastoma.

Adenoma↗
PubMed1976

Evidence for the presence of a vasoactive substance (possibly involved in the aetiology of cerebral arterial spasm) in cerebrospinal fluid from patients with subarachnoid haemorrhage.

Cerebrospinal fluid from patients with subarachnoid haemorrhage and cerebral arterial spasm contracted the isolated basilar artery and potentiated contractions produced by 5-hydroxytryptamine, noradrenaline, and six prostaglandins. The unidentified substance in cerebrospinal fluid probably plays a role in the aetiology of cerebral arterial spasm.

Adolescent↗
PubMed1975

The synthesis of 5S RNA and its relationship to 18S and 28S ribosomal RNA in the bobbed mutants of Drosophila melanogaster.

Ribosomes contain one molecule each of 5S, 18S and 28S RNA. In Drosophila melanogaster although the genes for 18S + 28S are physically separated from the 5S RNA genes, the multiplicity of various ribosomal RNA genes is roughly the same. Thus a coordinate synthesis of these three molecules might seem feasible. This problem has been approached by determining the molar ratios of various RNA's in ovaries and in adult flies. In ovaries there is a slight excess of 5S RNA molecules over other rRNA's, but in adult flies no such differences exist. Bobbed mutants also have the same molar ratios as wild-type flies. Results on 5S RNA synthesis in both in vitro and in vivo studies show that it is reduced in coordination with 18S + 28S rRNA in the bobbed mutants of Drosophila melanogaster. Various possibilities are discussed in considering the implications of these results.

DNA↗
PubMed1975

Pupillary constriction and ptosis following caudal epidural analgesia.

This study reports pupillary changes occurring in seventeen of twenty pregnant women at term who received caudal analgesia for the relief of pain in the first and second stages of labour. It is suggested that 10 ml or more of analgesic solution, injected into the sacral epidural space, reaches high enough (probably to T1) to cause meiosis and/or ptosis.

Anesthesia, Caudal↗
PubMed1975

Indian students' perceptions of the ideal self, the ideal leader, the ideal teacher, Indira Gandhi and the business executive.

The Activity Vector Analysis (AVA) was administered to three samples drawn from a population of graduate students at an Indian university. Results indicated a high positive relationship among the perceptions of the ideal self, ideal teacher, and ideal leader. Likewise, the consensual profile of Indira Gandhi was found to be quite similar to the ideal self cluster (r = .96). The collective perception of the business executive, however, was only remotely similar to the other two character profiles.

Adolescent↗
PubMed1974

Ribosomal RNA cistron multiplicity and nucleolar organizers in hexaploid wheat.

The ribosomal DNA (DNA complementary to ribosomal RNA) content of twelve different wheat genotypes has been studied. Some of these genotypes are aneuploids with deletions or additions of chromosomes bearing nucleolar organisers. The rDNA contents of these genotypes provide several examples of a clear departure from a correlation between the number of rRNA cistrons and the number of nucleolar organisers. Thus the number of rRNA cistrons per nucleolar organiser is not constant in wheat. Wheat DNA was found to have a mean buoyant density of approximately 1.702 g/cc for all genotypes studied and rRNA hybridized selectively to DNA of buoyant density approximately 1.710 g/cc. The thermal stabilities of all the rRNA/DNA hybrids were essentially identical.

Cell Nucleolus↗