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Biomedical subjects

M Harris

Publications and source records attributed to M Harris.

At least 667 records · Page 37Linked to original sources
PubMed1978

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on lipid profiles in tissue of the Fischer rat.

Female Fischer 344 rats were given single oral doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 10, 50 or 100 microgram/kg, and sacrificed 1, 3, 10, 14 or 21 days later. The fatty livers caused by a sub-lethal dose of TCDD involved a temporary increase in triglyceride and free fatty acid levels, with a persistent decrease in levels of sterol esters. In contrast, the fatty livers resulting from a lethal dose of TCDD involved a large increase in cholesterol esters and free fatty acids, with little change in triglyceride levels. These changes appeared to result in part from damage sustained by lysosomes. TCDD also altered the lipoprotein composition of the serum, the fatty acid composition of various lipid classes in liver and serum, and the ultrastructure of the liver (formation of myeloid bodies). A rapid, dose-dependent effect of TCDD, was the elevation of levels of organic-soluble fluorescent pigment in the heart. This pigment was found to match a previously characterized fraction of lipofuscins in fluorescence spectrum and chromatographic properties. The relatioship of these observations to a possible mechanism of toxicity for TCDD involving radical-induced lipid peroxidation is discussed.

Animals↗
PubMed1978

Cytoplasmic transfer of resistance to antimycin A in Chinese hamster cells.

A mutant subline of V79 Chinese hamster cells resistant to antimycin A (ANT) was obtained by treatment with ethyl methanesulfonate followed by serial selection in ANT-containing medium. Clonal derivatives of the resistant line are less susceptible than parent cells to growth inhibition by ANT in mass populations and show a higher plating efficiency in graded levels of inhibitor. Resistance to ANT is stable in drug-free medium and follows a pattern of incomplete dominance in hybrids between resistant and sensitive cells. No cross-resistance to chloramphenicol or other unrelated compounds was observed. Cytoplasmic transmission of ANT resistance can be readily demonstrated by fusing enucleated cytoplasts from resistant donors to sensitive recipient cells. The resulting cytohybrids ("cybrids") grow selectively in ANT but are identical karyotypically with the recipient cell type. As a putative mitochondrial marker, ANT resistance may be usefully combined with chloramphenicol resistance for studies on segregation and recombination in the mitochondrial genome of mammalian cells.

Antimycin A↗
PubMed1978

Primary signet ring cell carcinoma of the breast.

Three examples of primary signet ring cell carcinoma of the breast are described. This form of breast carcinoma deserves recognition as an entity because its prognosis may differ from colloid carcinoma of the breast and because of potential difficulty in distinguishing it from metastatic carcinoma.

Adenocarcinoma, Mucinous↗
PubMed1978

Mucin-producing carcinomas of the breast: ultrastructural observations.

The ultrastructural characteristics of mucin production in mammary mucoid carcinoma, signet ring cell carcinoma (Harris, Wells & Vasudev 1978), papillary carcinoma and lobular carcinoma are compared. The mucin in lobular carcinoma is confined to intracytoplasmic lumina whereas it is present as membrane bound granules in the other three types, although intracytoplasmic lumina also occur in the latter. A possible origin of intracytoplasmic lumina from distended Golgi cisternae is proposed. Possibly, extracellular mucin acts as a mechanical barrier between tumour cells and lymphatics, thus explaining the good prognosis of typical mucoid carcinomas.

Adenocarcinoma, Mucinous↗
PubMed1978

Pure Sertoli cell tumour of the ovary: report of a case with ultrastructural observations.

A case of pure Sertoli cell tumour of the ovary is described. Unusual features were its great size, lack of clinical hormonal activity and the presence of granulomas in its interstitium. Mitochondria with tubular christae are described for the first time in such a tumour. These, together with lipid droplets and plentiful smooth endoplasmic reticulum, suggest a potential for steroid hormone synthesis which was not expressed clinically. Dense membrane-bound granules of undetermined type were present in large numbers. The presence of cilia and microvilli, and the absence of annulate lamellae and Charcot-Böttcher crystalloids, suggests that the tumour cells may not be truly of Sertoli type.

Aged↗
PubMed1978

A sarcoma of myofibroblasts: an ultrastructural study.

A low-grade spindle cell sarcoma was shown by electron microscopy to be composed of myofibroblasts. It is suggested that the occurrence of myofibroblasts in spindle cell sarcomas might be of prognostic significance and that a systematic study to elucidate this point would be a valuable exercise.

Adolescent↗
PubMed1978

Odontogenic cyst growth and prostaglandin-induced bone resorption.

Forty-six odontogenic cysts produced significant quantities of bone-resorbing prostaglandins (PGs) in tissue culture. The follicular and periapical cysts released a mixture of PGEs and PGFs, while the keratocysts released only PGE2. There were also quantitative differences between the cyst types. Follicular cysts produced small quantities, as did keratocysts when allowance was made for their thin walls, whereas periodontal cysts are capable of relatively high activity. This prostaglandin activity can be related to the clinical behaviour of these lesions.

Bone Resorption↗
PubMed1977

Bronchodilator effect of hexoprenaline aerosol in bronchial asthma and chronic bronchitis.

The bronchodilator effects of aerosols of hexoprenaline (200 microgram and 400 microgram), and salbutamol (200 microgram) were compared in 15 patients with asthma, and nine patients with chronic bronchitis. In both groups of patients, hexoprenaline and salbutamol produced a similar increase in the forced expiratory volume in one second (FEV1), and mean percentage increase in FEV1. Neither drug caused tachycardia or arrhythmia. It was concluded that hexoprenaline aerosol was a safe and effective bronchodilator.

Adult↗
PubMed1977

Cognitive mediators between patients' social class and therapists' evaluations.

Previous research has shown that therapists are more likely to accept middle-class than lower-class persons for psychotherapy and to rate middle-class patients more favorably than lower-class patients. One explanation that has been offered is that lower-class patients may not conceptualize their experiences in a manner compatible with traditional kinds of therapy. This study investigated several cognitive variables that could theoretically serve as mediators between patients' social class and therapists' differential evaluations--specifically, verbal intelligence, psychological differentiation, and locus of control. Therapists evaluated patients after the initial therapy session. Results indicated that psychological differentiation was a mediator for therapists' judgments of both patients' desire for structure and their suitability for psychotherapy. Similarly, a locus of control orientation emphasizing the role of chance functioned as a mediator of therapists' judgments of suitability.

Attitude of Health Personnel↗
PubMed1977

The ultrastructure of tubular carcinoma of the breast.

The ultrastructure of four tubular carcinomas of the breast is described. The neoplastic tubules are single layered and lack a myo-epithelial component, an important feature in distinguishing tubular carcinoma from sclerosing adenosis. Numerous myo-fibroblasts are present in the stroma of all four tumours and, since cells of this type have been recorded only occasionally in the stroma of other types of breast carcinoma, it is suggested that they may be a characteristic feature of tubular carcinomas.

Breast Neoplasms↗
PubMed1977

The world hypotheses scale: rationale, reliability and validity.

Theoretical descriptions are presented for four different sets cognitive assumptions concerning the fundamental meaning of events. These cognitive assumptions or world hypotheses are called formism, mechanism, organicism, and contextualism. The development of a 12-item scale to measure individual preferences for these world hypotheses is described. Finally, several empirical studies are reported in which diverse behavioral correlates have been found for individuals preferences among world hypotheses. Specifically, significant results have been obtained for choice of careers, stability of friendships, and success in both group and individual therapies.

Journal Article↗