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Biomedical subjects

S Barton

Publications and source records attributed to S Barton.

At least 91 records · Page 5Linked to original sources
PubMed1988

The effect of a bradykinin antagonist on vasodilator responses with particular reference to the submandibular gland of the cat.

A bradykinin analogue, D-Arg[Hyp3, Thi5,8, D-Phe7]-Bk, antagonized the vasodilator effect of bradykinin injected close-arterially in the submandibular salivary gland of the cat, without affecting that due to acetylcholine or nerve stimulation. The same analogue also antagonized the hypotensive response to bradykinin injected intravenously in cats and rabbits. We conclude that functional hyperaemia in the submandibular gland of the cat is not due to the release of bradykinin by salivary kallikrein.

Animals↗
PubMed1988

Psychosocial implications of recurrent genital herpes simplex virus infection.

Fifty seven patients experiencing first attacks of genital herpes simplex virus infection (HSVI) were compared with 50 patients who were concerned about frequently recurring attacks despite routine counselling and reassurance. Using the general health questionnaire this latter group was found to be more psychologically distressed and more socially naive than the first attack group, as measured by socioeconomic class and the lie score of the Eysenck personality questionnaire; otherwise the two groups were similar. Patients presenting to clinics with frequently recurring genital HSVI may therefore be especially psychologically distressed, socially naive, and disadvantaged. Managing these patients needs to include understanding these problems as well as giving advice and using antiviral agents.

Adolescent↗
PubMed1988

The natural history of early cervical neoplasia and cervical human papillomavirus infection.

This article deals with the natural history of cervical human papillomavirus infection and precancer. It traces the development of the transformation zone and maturation of the normal squamous epithelium. Potential aetiological agents and a possible cofactor are briefly discussed. The natural history of premalignant disease and its relationship to invasive disease is also covered.

Cell Transformation, Viral↗
PubMed1987

Provision of the immunoglobulin heavy chain enhancer downstream of a test gene is sufficient to confer lymphoid-specific expression in transgenic mice.

To test whether the immunoglobulin heavy chain enhancer is sufficient to direct lymphoid specific gene expression in vivo, we have incorporated into the mouse germ line a test gene (chloramphenicol-acetyl transferase) whose transcription is potentiated by the enhancer. Analysis of transgenic mice bearing single-copy integrations of the injected DNA indicates that provision of the enhancer downstream of the test gene (beyond the polyadenylation site) is sufficient to direct lymphoid-specific expression. The tissue specificity is considerable as judged by the fact that transgene expression is at least one thousandfold higher in spleen than in liver. Within the lymphoid family, expression of the transgene is much higher in surface IgM+ spleen cells than in thymocytes high in Thy-1 expression, suggesting that the enhancer preferentially directs expression to cells of the B lineage.

Acetyltransferases↗
PubMed1987

Centralized obesity and cardiovascular disease risk in Mexican Americans.

The association between body fat distribution patterns and cardiovascular disease risk variables (high density lipoprotein (HDL) cholesterol, total cholesterol, diastolic and systolic blood pressures, and fasting blood glucose levels) was sought in a sample of Mexican American adults who were studied during 1981-1983 in Starr County, Texas. In the sample, all diabetics were excluded to see whether centralized obesity carried any risk for cardiovascular disease independent of diabetes. A component of centralized body fat distribution was identified through the use of principal components analysis of five skinfold measurements, which included the upper and lower extremities and trunk areas. The centralized obese were compared with generalized (peripheral) obese and nonobese controls in four subgroups of the population: younger and older adult males and females. The means of all cardiovascular risk variables were in a direction indicating that the centralized obese were significantly at greater risk than nonobese controls (in particular, HDL cholesterol, total cholesterol, and blood glucose levels). The generalized obese differed from the centralized obese in having significantly lower blood glucose levels, and tended to be intermediate between centralized obese and nonobese controls in the other variables. The data confirm that centralized obesity as defined by a linear combination of skinfold measures works in the same way as the waist-to-hip circumference ratio in describing a body build factor which heightens the risk of cardiovascular disease in the obese independent of the clinical diabetic state.

Adult↗
PubMed1987

The effects of isotretinoin on follicular and sebaceous gland differentiation.

Follicular and sebaceous gland cell differentiation was investigated during treatment of acne patients with isotretinoin. Sebaceous glands were significantly reduced in volume and showed decreased metabolic activity as measured by glucose-6-phosphate dehydrogenase and succinic dehydrogenase enzyme activities. There was no measurable change in the volume of follicular duct epithelium or in its metabolic activity during treatment. Metabolic activity was also unchanged in the interfollicular epidermis, contrasting with the effects of another retinoid, etretinate. These findings provide no support for the proposition that alteration in the process of follicular keratinization forms a substantial part of the mode of action of isotretinoin.

Acne Vulgaris↗
PubMed1987

Cytogenetic evidence for involvement of B lymphocytes in acquired idiopathic sideroblastic anemias.

We studied the cellular distribution of an unusual chromosomal abnormality, an interstitial deletion of the long arm of chromosome 13, in the peripheral blood lymphocytes of two patients with acquired idiopathic sideroblastic anemia (AISA). We found no metaphases containing the 13q- abnormality in preparations of phytohemagglutinin (PHA)-stimulated lymphocytes from either patient. In both cases, however, some metaphases from Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines contained the clonal karyotypic abnormality. These observations indicate that B lymphocytes but not T cells are expressed as members of the clonal cohort of cells. Our results strongly suggest that the initial pathogenetic events that led to expansion of the 13q- clone occurred in a progenitor cell capable of giving rise to both hematopoietic and B lymphoid cells.

Aged↗
PubMed1986

Differentiation of the myocardial rudiment of mouse embryos: an ultrastructural study including freeze-fracture replication.

The differentiation of the myocardial rudiment was examined in mouse embryos, isolated between the afternoons of the eighth and ninth days of gestation, by means of transmission electron microscopy of ultrathin sections and of freeze-fracture replicas; some of the material used for sectioning was labelled with ruthenium red. Formation of the presumptive pericardial cavity commences during the late presomite stage (afternoon of the eighth day) and the myocardial rudiment originates in situ as a thickening of the splanchnic pericardial lining. Initially, the myocardium comprises an epithelium or plate directly exposed to the pericardial lumen and overlying a separate layer of endocardial elements. As the heart tube bulges into the pericardial coelom, it becomes surrounded by a sleeve of myocardium which thickens and stratifies during the ninth day and subsequently (on the tenth day) acquires an epicardial covering of flattened cells. The myocardium commences pulsations at or about the 3-4 somite stage (morning of the ninth day) by which time the myoblasts already contain striated myofibrillae and specialised cell junctions. From its earliest appearance, the myocardial plate contains tight junctions and desmosomes between the lateral borders of the apical parts of the myoblasts. Gap junctions soon appear in the same regions and they increase in number and extent, as the myoblasts elongate and divide, thus establishing contact in various planes; they are supplemented by the formation of fasciae adherentes and of more desmosomes. On the other hand, tight junctions decline in extent and are eventually confined to the epicardium. Other features such as caveolae and T-tubules are not established by the end of the ninth day and coupling arrangements of the sarcoplasmic reticulum are only in the rudimentary stages of formation.

Animals↗
PubMed1985

Quantitative evaluation of the dermal vasculature of diabetics.

The dermal microvasculature has been compared in 51 diabetics and 51 matched non-diabetic controls using tissue measurement techniques and functional assessments of blood vessel reactivity. Blood vessel walls were thicker in different groups of diabetics than the controls (p less than 0.01) but the degree of thickness did not differ between patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus or between diabetics with and without vascular complications. Vascular lumina were narrower in diabetics than in controls (p less than 0.01) and diabetics with vascular complications had a greater reduction in luminal area than those without such complications (p less than 0.001) but the luminal area did not differ between the insulin-dependent and the non-insulin-dependent groups. The luminal perimeter was also reduced in the diabetic group compared to controls. The weal and flare response to intracutaneous histamine acid phosphate (50 micrograms) was markedly decreased (p less than 0.001) in diabetic subjects compared with controls, as was the response to a topically applied vasodilator (Transvasin). The degree of reduction did not differ between patients with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but diabetics with vascular complications show impaired responses as compared to those without. The maximum increase in skin temperature on the volar surface of the right middle finger during a period of reactive hyperaemia following 3 min of cuff-induced ischaemia was also markedly decreased in diabetics compared with control subjects. It did not differ between those with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but did between diabetics with vascular complications as compared with those without. This study confirms that the cutaneous vasculature of diabetics differs markedly from that of matched control subjects. The results also indicate that there are significant differences between diabetics with vascular complications and those without. The quantitative approaches adopted may have predictive value.

Adult↗
PubMed1984

A study of vasoactive intestinal peptide and acetylcholine as possible mediators of vasodilatation in the cat submandibular gland.

Vasoactive intestinal polypeptide (VIP) is a powerful vasodilator agent in the submandibular gland of the cat, and its effect can be reduced by avian pancreatic polypeptide (APP), or by desensitization of the gland's blood vessels to VIP. However, the vasodilatation caused by parasympathetic nerve stimulation is not reduced by either of these means. We conclude, therefore, that VIP is unlikely to be a major mediator of this atropine-resistant vasodilatation. Experiments with a potentiator of acetylcholine, eserine, and with a depleter, suggest that acetylcholine plays some role in this vasodilatation, but it too does not appear to be the major physiological mechanism. Substance P and ATP were neither potent nor consistent vasodilators and are unlikely mediators.

Acetylcholine↗