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Biomedical subjects

G Parry

Publications and source records attributed to G Parry.

At least 109 records · Page 6Linked to original sources

Social support and life events in working class women. Stress buffering or independent effects?

Several authors have suggested that social support reduces the risk of psychiatric disorder by providing a "buffer" against the adverse effects of stressful events. Others have proposed, in contrast, that social support is beneficial irrespective of life stress. We addressed this issue in a community survey of 193 working class mothers by measuring social support, threatening life events, psychiatric symptomatology, and psychological well-being via a detailed assessment combining a standardized interview and case-identification procedure with self-report questionnaires yielding continuous measures of distress and well-being. Subject selection minimized confounding between support and events. The effects of life stress and social support were found to be largely independent of one another, although detailed analysis suggested that the conclusions drawn in such studies are affected by the measures and statistics used.

Adult↗

The case of the anxious executive: a study from the research clinic.

Most psychotherapists are neither active researchers nor consumers of research findings. Research approaches are needed which build a bridge between clinical realism and independent evidence, but which are applicable in National Health Service settings by clinicians lacking substantial research resources. A new method of clinical inquiry is described which combines measurement techniques developed in psychotherapy research with the therapist's session notes and client perceptions of helpful events in therapy. The method is illustrated by a case study which examines the content of helpful and unhelpful therapy sessions.

Adult↗

Collagenous substrata regulate the nature and distribution of glycosaminoglycans produced by differentiated cultures of mouse mammary epithelial cells.

We have investigated the influence of culture substrata upon glycosaminoglycans produced in primary cultures of mouse mammary epithelial cells isolated from the glands of late pregnant mice. Three substrata have been used for experiments: tissue culture plastic, collagen (type I) gels attached to culture dishes, and collagen (type I) gels that have been floated in the culture medium after cell attachment. These latter gels contract significantly. Cells cultured on all three substrata produce hyaluronic acid, heparan sulfate, chondroitin sulfates and dermatan sulfate but the relative quantities accumulated and their distribution among cellular and extracellular compartments differ according to the nature of the culture substratum. Notably most of the glycosaminoglycans accumulated by cells on plastic are secreted into the culture medium, while cells on floating gels incorporate almost all their glycosaminoglycans into an extracellular matrix fraction. Cells on attached collagen gels secrete approx. 30% of their glycosaminoglycans and assemble most of the remainder into an extracellular matrix. Hyaluronic acid is produced in significant quantities by cells on plastic and attached gels but in relatively reduced quantity by cells on floating gels. In contrast, iduronyl-rich dermatan sulfate is accumulated by cells on floating gels, where it is primarily associated with the extracellular matrix fraction, but is proportionally reduced in cells on plastic and attached gels. The results are discussed in terms of polarized assembly of a morphologically distinct basal lamina, a process that occurs primarily when cells are on floating gels. In addition, as these cultures secrete certain milk proteins only when cultured on floating gels, we discuss the possibility that cell synthesized glycosaminoglycans and proteoglycans may play a role in the maintenance of a differentiated phenotype.

Animals↗

Interaction of mouse mammary epithelial cells with collagen substrata: regulation of casein gene expression and secretion.

Mouse mammary epithelial cells (MMEC) secrete certain milk proteins only when cultured on floating collagen gels. We demonstrate here that modulation of milk proteins by substrata is manifested at several regulatory levels; (i) Cells cultured on floating collagen gels have 3- to 10-fold more casein mRNA than cells cultured on plastic or attached collagen gels. (ii) Cells on the latter two "flat" substrata, nevertheless, synthesize a significant amount of caseins, indicating that the remaining mRNA is functional. (iii) Cells on all substrata are inducible for casein mRNA and casein proteins by prolactin, but the extent of induction is greater on collagen than that on plastic--i.e., the substratum confers an altered degree of inducibility. (iv) Cells on all substrata synthesize casein proteins at rates proportional to the amount of casein mRNA, but the newly synthesized caseins in cells on plastic are degraded intracellularly, whereas those synthesized by cells on floating gels are secreted into the medium. (v) Cells on all substrata examined lose virtually all mRNA for whey acidic protein despite the fact that this mRNA is abundant in the mammary gland itself; we conclude that additional, as-yet-unknown, factors are necessary for synthesis and secretion of whey acidic protein in culture.

Animals↗

Inflammatory neuropathy in homosexual men with lymphadenopathy.

Twelve homosexual men had peripheral neuropathy with fever, night sweats, and lymphadenopathy. Sensory symptoms predominated, but there was also weakness and cranial nerve dysfunction. Manifestations were multifocal in nine and distal and symmetric in three. CSF was abnormal in all eight patients examined. Sural nerve in five patients showed axonal degeneration, accompanied in two by segmental demyelination. Four patients had epineurial and endoneurial perivascular chronic inflammatory cells without evidence of vasculitis. Neuropathy remitted spontaneously in six patients. Four patients received steroids without clinical response, although one later responded to plasmapheresis-lymphocytapheresis. Four patients later progressed to AIDS.

Acquired Immunodeficiency Syndrome↗

Modulation of secreted proteins of mouse mammary epithelial cells by the collagenous substrata.

It has been shown previously that cultures of mouse mammary epithelial cells retain their characteristic morphology and their ability to produce gamma-casein, a member of the casein gene family, only if they are maintained on floating collagen gels (Emerman, J.T., and D.R. Pitelka, 1977, In Vitro, 13:316-328). In this paper we show: (a) Cells on floating collagen gels secrete not only gamma-casein but also alpha 1-, alpha 2-, and beta-caseins. These are not secreted by cells on plastic and are secreted to only a very limited extent by cells on attached collagen gels. (b) The floating collagen gel regulates at the level of synthesis and/or stabilization of the caseins rather than at the level of secretion alone. Contraction of the floating gel is important in that cells cultured on floating glutaraldehyde cross-linked gels do not secrete any of the caseins. (c) The secretion of an 80,000-mol-wt protein, most probably transferrin, and a 67,000-mol-wt protein, probably butyrophilin, a major protein of the milk fat globule membrane are partially modulated by substrata. However, in contrast to the caseins, these are always detectable in media from cells cultured on plastic and attached gels. (d) Whey acidic protein, a major whey protein, is actively secreted by freshly isolated cells but is secreted in extremely limited quantities in cultured cells regardless of the nature of the substratum used. alpha-Lactalbumin secretion is also decreased significantly in cultured cells. (e) A previously unreported set of proteins, which may be minor milk proteins, are prominently secreted by the mammary cells on all substrata tested. We conclude that while the substratum profoundly influences the secretion of the caseins, it does not regulate the expression of every milk-specific protein in the same way. The mechanistic implications of these findings are discussed.

Animals↗

The fragile self: narcissistic disturbance and the protective function of depression.

The role of self-esteem in the aetiology of depressive disorders is not limited to negative self-evaluations. A broader concept, embracing the experience of the self, is necessary. A developmental model of self-esteem regulation is proposed, derived in part from Mahler's work on separation-individuation in infants and Kohut's work on narcissism. A concept of a 'fragile self' is formulated and developed; the depressive state is seen as protecting this fragile self. The model provides a coherent account of individual differences in proneness to depression (in interaction with environmental factors) which is useful to psychotherapists, yet open to empirical test and research use. The model is discussed in relation to psychological research on depression and implications for clinical practice are outlined.

Depressive Disorder↗

Detection of transformed cells using a fluorescent probe: the molecular basis for the differential reaction of fluorescamine with normal and transformed cells.

Normal and transformed fibroblasts can be discriminated by a flow cytometry assay on the basis of their differential reaction with fluorescamine. The cause of altered reactivity of transformed cells with this fluorescent probe has been investigated by a detailed analysis of its reaction with chicken embryo fibroblasts transformed by a temperature sensitive mutant of Rous sarcoma virus. The subcellular distribution of fluorescent adducts characterized by cell fractionation and gel electrophoresis procedures supports the hypothesis that transformed cells possess a surface barrier which decreases the accessibility of fluorescamine to reactive macromolecules. The barrier has been identified as being composed at least partly of hyaluronic acid, because of the ability of purified and specific hyaluronidase (from Streptomyces hyalurolyticus) to modulate the response of transformed cells to fluorescamine. Enzyme treatment of transformed cells prior to reaction with fluorescamine causes them to resemble nontransformed cells both in the nature of components labeled and in their fluorescence intensity. It is suggested that fluorescamine monitors an altered surface hyaluronic acid composition which occurs upon transformation. Its significance is discussed in terms of the known physical properties of the molecule and the finding that it is an early event in the process of transformation.

Animals↗

Role of src gene in growth regulation of Rous sarcoma virus-infected chicken embryo fibroblasts.

We report here a study of the mechanisms leading to loss of growth control in chicken embryo fibroblasts transformed by Rous sarcoma virus (RSV). We have been particularly concerned with the role of the src gene in this process, and have used RSV mutants temperature sensitive (ts) for transformation to investigate the nature of the growth regulatory lesion. The two principal findings were (1) the stationary phase of the cell cycle (G1) in chick embryo fibroblasts seems to have two distinct regulatory compartments (using the terminology of Brooks et al. we refer to these as 'Q' and 'A' states). When rendered stationary at 41.5 degrees C by serum deprivation, normal cells enter a Q state, but cells infected with the ts-mutant occupy an A state. (2) Whereas normal cells can occupy either state depending on culture conditions, the ts-infected cells, at 41.5 degrees C, do not seem to enter Q even though a known src gene product, a kinase, is reported to be inactive at this temperature. We discuss the possibility that viral factors other than the active src protein kinase influence growth control in infected cultures.

Animals↗

The uncoupled regulation of fibronectin and collagen synthesis in Rous sarcoma virus transformed avian tendon cells.

We have investigated the regulation of fibronectin and procollagen synthesis in normal and Rous sarcoma virus transformed primary avian tendon cells. These two proteins interact at the cell periphery and both are reportedly lost upon transformation. We thus examined whether their synthesis was coordinately regulated in Rous sarcoma virus-infected cells. It was found that while the synthesis of both pro alpha 1 and pro alpha 2 peptides was reduced upon transformation, the synthesis of fibronectin was not altered. Nevertheless, long term radiolabeling demonstrated that fibronectin levels were reduced in transformed cells. It is concluded that the reduction in levels of these components at the surface is brought about by different mechanisms; collagen levels being regulated by procollagen synthesis and fibronectin levels by degradation and/or release into the culture medium. The possibility is discussed that fibronectin is lost from the cell periphery of primary avian tendon cells as a consequence of decreased levels of anchoring collagen molecules.

Animals↗

Cryptococcal granuloma presenting as an intracranial mass.

A case of cryptococcosis of the central nervous system presenting as an intracranial space occupying lesion is described. The world literature and epidemiology of this unusual disease are surveyed. Problems in the diagnosis and the use of modern diagnostic techniques are discussed. The authors suggest that cryptococcosis should be included in the differential diagnosis of an intracranial space occupying lesion.

Adult↗

Detection of an early surface change during oncogenic transformation.

Fluorescamine, which can label surface components of cells grown as monolayers in culture, has been used to probe alterations in chicken embryo fibroblasts infected with a temperature-sensitive mutant of Rous sarcoma virus, Prague A, LA24. The fluorescence of bound fluorescamine on cells at the permissive temperature (35 degrees) was found to be about 1/3 that of cells cultured at the nonpermissive temperature (41 degrees). During development of the transformed phenotype, i.e., after transfer of the cells from 41 degrees to 35 degrees, the decrease in surface fluorescence was observed to be an early event occurring within the first 4-8 hr after temperature shift. This alteration took place on a time scale similar to that of changes in 2-deoxyglucose transport and an increased rate of DNA synthesis, but before any major morphological changes. The change was related to cell transformation rather than to growth differences of the cells at the two temperatures. Further, it was found that fluorescamine was not monitoring the loss of LETS glycoprotein from the surface or the loss of any other surface components that could be detected by lactoperoxidase-catalyzed iodination of surface proteins. When fluorescamine-labeled components were resolved by polyacrylamide gel electrophoresis, significant differences were seen between components from cells cultured at 35 degrees compared with those from cells cultured at 41 degrees. Based on these results, possible mechanisms accounting for the fluorescence differences are suggested.

Avian Sarcoma Viruses↗