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Biomedical subjects

C Morris

Publications and source records attributed to C Morris.

248 records · Page 14Linked to original sources
PubMedDate not supplied

Investigation by immunofluorescence of arterial lesions in rabbits on two different lipid supplements and treated with pyridinol carbamate.

Rabbits maintained on a pellet diet supplemented with cholesterol, or on a semi-synthetic diet containing beef fat but no added cholesterol, have been studied in relation to their development of hyperlipidaemia and of lipid-filled arterial lesions. The influence of pyridinol carbamate on animals on both diets was also examined but found to produce no significant effect. Animals on both diets developed a hyperlipoproteinaemia. In cholesterol-fed animals this developed quickly, became gross, and was characterized by the presence of an anomalous lipoprotein of very low density, large molecular size and abnormally high cholesterol content. Beef fat fed animals showed a more moderate hyperlipidaemia which developed more slowly and the lipoproteins qualitatively resembled those in normal rabbits. Differences in the rate and severity of development of aortic lesions between the two different dietary supplements were found to reflect differences in the duration and intensity of hyperlipoproteinaemia between the groups. Arterial lesions in cholesterol-fed animals were more extensive and contained larger numbers of fat-filled cells than those in beef fat-fed animals. Comparisons were made (in many cases on the identical section) between lesions treated with a fluorescein labelled antiserum to total rabbit serum low density lipoproteins (TLDL) and with a conventional lipid stain. Precise agreement was found between the distribution of lipid reacting with Oil red 0 and specific fluorescence for TLDL in endothelial cells, in extracellular deposits in the intimal ground-substance and in medial smooth muscle cells. But fat-filled cells in the intima and in reticulo-endothelial tissue showed variable immunofluorescent reactivity. The reason for this discrepancy is discussed. Agreement between the distribution of conventional lipid staining and specific immunofluorescence for TLDL was also found in extracellularly distributed material in arterioles and smaller vessels at certain sites. It is suggested that these results establish that rabbit TLDL serve as the vehicles transporting lipid into the experimental lesions, just as the homologous human lipoproteins do in human atherosclerosis.

Animals↗
PubMedDate not supplied

Hoarding, compulsive buying and reasons for saving.

Two studies examined hypotheses about compulsive hoarding, compulsive buying and beliefs about saving and discarding derived from the cognitive-behavioral model of compulsive hoarding [Frost, R. O. and Hartl, T. (1996). A cognitive behavioral model of compulsive hoarding. Behaviour Research and Therapy, 34, 341-350.]. Study 1 examined the hypotheses in a college student population, while study 2 compared members of a support group for hoarding and clutter-related problems with a nonclinical control. Across studies the hypotheses were supported. Compulsive hoarding was associated with compulsive buying and the frequency of acquisition of possessions discarded by others, suggesting that compulsive acquisition may be a broader construct than compulsive buying among people with hoarding problems. Regarding its association with OCD symptoms, hoarding was most closely associated with the impaired mental control features of OCD. Finally, offa hoarding-related task, hoarding was associated with a greater frequency of reasons to save, but was not associated with fewer reasons to discard a target possession.

Adult↗
PubMedDate not supplied

Neuritogenic-neurotoxic effects of membrane-associated forms of amyloid precursor protein.

The membrane-bound glycoprotein, amyloid precursor protein (APP), plays a central role in Alzheimer's disease (AD). The present paper investigates the neuritogenic-neurotoxic properties of this protein and relates them to possible aetiopathological mechanisms in AD. Marked differences in neuritic differentiation were detected when comparing untransfected tetraploid mouse neuroblastoma cells (or vector only cells) with transfected cells overexpressing APP(751). Transfected cells developed neurites quicker, and whereas all transfected cells differentiated, the degree of differentiation of untransfected cells was more variable. Fully differentiated transfected and untransfected cells had marked differences in neuritic morphology. Transfected cells had more neurites per cell, these being shorter and more branched than neurites on untransfected cells. The precocious differentiation of transfected cells was not maintained with neuritic process disintegration and cell death occurring from the seventh day onwards. Untransfected cells continued to extend their neuritic processes for up to five weeks. Membrane-associated forms of APP were responsible for these effects, rather than secreted APP or the beta/A4-peptide. Combined data from Western blot and immunocytochemical procedures showed a prominent accumulation of APP-C-terminal fragments in the perinuclear region, neuritic varicosities and growth cones of transfected cells, suggesting their involvement in the neuritogenic-neurotoxic process. Similar neuritogenic-neurotoxic mechanisms occurring in vivo, in association with compensatory synaptoplastic responses in the aged brain, may be part of the pathological process in AD.

Alzheimer Disease↗
PubMedDate not supplied

EGF-receptor and extracellular matrix changes in mouse pulmonary carcinogenesis.

Malignant Balb/c mouse lung cell clones related to alveologenic carcinoma exhibited low levels of epidermal growth factor (EGF) receptor activity compared to nonmalignant cell clones. Immunoprecipitation of cell homogenates and immunohistochemistry on urethane-induced lung tumors suggest that the absence of activity reflects decreased amounts of EGF receptor protein. Low levels of EGF receptor alone cannot cause neoplastic transformation, since a nonneoplastic cell cone, B5D3, exhibited low levels of EGF receptor despite its nontransformed phenotype. The reduced levels of EGF receptor in malignant clones have been mimicked by long-term (12 h) treatment of a nontransformed cell clone with 200 nM phorbol dibutyrate. The detection of mutated ras oncogene in the transformed cell lines, taken together with the EGF receptor findings, suggests that more than one alteration in the signal transduction pathway may be necessary for transformation in alveologenic adenoma and carcinoma cell systems. A further phenotypic feature of transformation, reduced expression of the extracellular matrix proteins fibronectin and laminin, may be mediated at the transcriptional level.

Animals↗
PubMedDate not supplied

Patient pull, Part II: The implications for design and development.

Listening to the consumer is a well-established business principle, but how well is it realized in the medical device industry? Part I of this article outlined the key drivers of change in the industry and the implications for various stakeholders. Part II focuses on the design and development process and discusses how to involve patients throughout the process to develop medical devices that people want to use.

Consumer Advocacy↗
PubMedDate not supplied

Technology and the legal discourse of fetal autonomy.

The relationship between society, medicine, and the law is multi-faceted and complex. This Article examines the process of, and the influences on, the construction of fetal personhood in the legal discourses in American and Commonwealth case law and statutes. It demonstrates how the physical and visual separation of the fetus, as made possible by medical advances, has influenced the development of legal doctrine relating to the rights of the fetus.

Abortion, Induced↗
PubMedDate not supplied

Central venous catheter placement: extending the role of the nurse.

OBJECTIVE: To improve the quality of the percutaneous tunnelled central venous catheter placement service for patients being treated for malignant disease. DESIGN: A clinical nurse specialist was specially trained to insert percutaneous tunnelled central venous catheters according to predetermined guidelines. Catheters were inserted under local anaesthetic in the outpatient department or the ward. The quality of the service was analysed and compared with the pre-existing service provided by junior medical staff. SUBJECTS: Two hundred adult patients with malignant disease seen between January 1995 and January 1996 at the Christie Hospital Trust. MAIN OUTCOME MEASURES: Success of the procedure, insertion-related infection rates and waiting times compared to historical controls. RESULTS: The rate of failed insertions fell from 20% to 3% with a concomitant reduction in surgical referrals; for 97% of patients waiting time was reduced to less than one working day compared with 80% previously. Line-related infection rates in the first thirty days following insertion fell from 10 episodes per 72 lines inserted to two episodes per 200 lines inserted. CONCLUSIONS: Training and using a clinical nurse specialist has improved the quality of service and gives junior doctors more opportunity to become competent in the technique of central venous catheter placement. The introduction of guidelines has encouraged a standard approach that facilitates audit.

Adult↗