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Biomedical subjects

M Harris

Publications and source records attributed to M Harris.

At least 451 records · Page 25Linked to original sources
PubMed1990

Fine needle aspiration cytology of salivary gland lesions: advantages and pitfalls.

Fine needle aspiration cytology (FNAC) was performed on 52 patients with salivary gland lesions. A definitive cytodiagnosis was possible in 45 cases: a sensitivity of 89% and a specificity of 94% was achieved. The pitfalls of FNAC of salivary gland lesions are reflected by the false positive and false negative rates which were 4%. Errors of cytodiagnosis are due to the morphological variability of these tumours which make sampling and interpretation difficult.

Biopsy, Needle↗
PubMed1990

Degenerative changes in masseter and temporalis muscles in limited mouth opening and TMJ ankylosis.

The masseter and temporalis muscles were studied ultrastructurally in eight cases suffering from restricted mouth opening and TMJ ankylosis. The changes varied from slight degeneration of muscle fibers, such as accumulation of lipid or lipofuscin deposits, Z-band streaming and derangement of myofilaments, in one case to moderate or severe changes of muscle atrophy and necrosis in the remaining seven cases. Nemaline bodies were also observed in one of these seven cases. In addition to these muscle changes neural degeneration especially of myelinated nerves were found in three of the cases studied. The present findings showed that in spite of the diversity of the underlying factors affecting the joint, there was many similarities in the changes observed within the muscle. It is postulated that these degenerative muscle changes probably play an important role in restricted mouth opening and TMJ ankylosis, and that some of these muscle pathology may be the result of neural involvement.

Actin Cytoskeleton↗
PubMed1990

Identification of factors associated with high breast cancer risk in the mothers of children with soft tissue sarcoma.

Information on the past medical history of the mothers of a population-based series of 177 children with soft tissue sarcoma was obtained by interview and from medical records. Eight mothers developed breast cancer, six premenopausally, compared with 3.26 expected (P = .04), but no excess of other types of cancers was detected. High breast cancer risk was associated with the following factors in the index child: age at diagnosis less than 24 months (relative risk [RR], 7.84), embryonal rhabdomyosarcoma (RR, 3.74), and male sex (RR, 3.02). Characteristics in the mother associated with high breast cancer risk were the following: late age at first birth (RR, 5.13), late age at birth of index child (RR, 5.69), and high birth-rank order of index child (RR, 4.08). The results suggest there may be a subset of childhood soft tissue sarcoma with a predominantly genetic etiology. The association between premenopausal breast cancer in the mother, late age at birth of index child, and early onset of soft tissue sarcoma in the index child suggests that these three events are not independent and that interactions between genetic and other factors may be important. The identification of a group of women at high risk for breast cancer affords an opportunity for screening and early detection. The study of cancer family syndromes may provide insights into underlying mechanisms in cancer genetics.

Adult↗
PubMed1990

Pet therapy for the homebound elderly.

The Visiting Nurses Association-Community Services, Inc., responding to community interest and support, developed a pet therapy program for homebound clients. Early reports indicate that the program has improved the physiological as well as psychosocial wellbeing of participants.

Aged↗
PubMed1990

What makes an effective manager?--health care and general management perceptions.

This paper explores the perceptions of Australian health service managers (and health service management students) regarding the qualities of effective managers, comparing and contrasting these views with those of Australian general managers (and general management students). The study forms part of a wider international project aimed at exploring the role of national culture in managerial behaviour and effectiveness. Overall, the skills dimension was perceived to be more important in terms of managerial effectiveness, particularly amongst health service managers, compared to the other main dimensions of knowledge and learning, beliefs and values and personality characteristics. Decision-making and planning and evaluation were considered to be the most important amongst the range of skills listed, followed by negotiation and conflict resolution. Health service managers rated pertinent technical knowledge more highly than any other aspect in the knowledge and learning dimension, indicating the importance of specialist education for health service managers. Some implications of these and other findings are discussed.

Attitude of Health Personnel↗
PubMed1990

Monovision.

Monovision has been a controversial contact lens correction modality for over 30 years. This paper addresses the major issues and concerns and considers them in the light of patient safety, visual efficiency and practitioner liability.

Adaptation, Ocular↗
PubMed1990

Acute subdural hematoma: morbidity and mortality related to timing of operative intervention.

In spite of major advances in the management of severe head injury (HI) acute subdural hematoma (ASDH) continues to be one of the most lethal of all intracranial injuries. Of 1,150 consecutive severe HI patients, 137 (12%) had ASDH. The following variables were assessed in regards to outcome morbidity/mortality from ASDH: mechanism of injury, age, sex, neurologic presentation, postoperative intracranial pressure (ICP), and timing from injury to operative evacuation of the ASDH. The only variables found to statistically correlate with outcome were presenting neurologic condition (p = 0.001) and elevated postoperative ICP greater than 45 mm Hg (p = 0.001). The timing from injury to operative evacuation of the ASDH in regards to outcome morbidity/mortality was not statistically significant even when examined at hourly intervals (p = 0.418).

Acute Disease↗
PubMed1989

Are germ cell tumors part of the Li-Fraumeni cancer family syndrome?

The occurrence of six cases of germ cell tumors, five testicular and one ovarian, in relatives of children with bone or soft tissue sarcomas is described. It is proposed that germ cell tumors may be an uncommon manifestation of the genetic predisposition to cancer that exists in the Li-Fraumeni cancer family syndrome.

Adult↗
PubMed1989

Structure-dependent induction of aryl hydrocarbon hydroxylase in human breast cancer cell lines and characterization of the Ah receptor.

The structure-dependent induction of aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin O-deethylase by 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, and 1,2,4,7,8-pentachlorodibenzo-p-dioxin was determined in the MCF-7, T47-D, and MDA-MB-231 human breast cancer cell lines. Both the MCF-7 and T47-D cells were responsive to the induction effects of the halogenated aryl hydrocarbons and the structure-induction relationships were comparable to the reported structure-activity (induction, receptor binding, and toxicity) relationships observed in rodents and rodent cells in culture. The induction of ethoxyresorufin O-deethylase in the T47-D cells was the most sensitive aryl hydrocarbon (Ah) receptor-mediated response in both cell lines and this enzyme activity was more inducible than aryl hydrocarbon hydroxylase. In contrast, the three congeners were inactive as monooxygenase enzyme inducers in the MDA-MB-231 cells. Despite the differential Ah responsiveness of the cell lines, incubation of the cells with [3H]-2,3,7,8-tetrachlorodibenzo-p-dioxin followed by extraction of the nuclei with high salt and velocity sedimentation analysis of the extracts showed that specifically bound nuclear Ah receptor complexes were present in the three cell lines. The sedimentation coefficients (and levels) for the nuclear receptors were 6.6 S (32.1 fmol/mg protein/mg DNA), 6.9 S (61.6 fmol/mg protein/mg DNA), and 7.4 S (38.2 fmol/mg protein/mg DNA) in the T47-D, MCF-7, and MDA-MB-231 cell lines, respectively. Cytosolic receptor was also detected in the MCF-7 and MDA-MB-231 cells. Thus, despite the differences in Ah responsiveness of the T47-D and MDA-MB-231 cells, comparable levels of nuclear receptor were detected in both cell lines. Furthermore, the elution profiles of the nuclear receptors from DNA-Sepharose columns by using a salt gradient were similar and this suggested that defects in the DNA-binding activity of MDA-MB-231 nuclear receptor complexes were not major factors associated with their failure to respond to 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds.

Aryl Hydrocarbon Hydroxylases↗
PubMed1989

Induction of cytochrome P450-dependent monooxygenase activities in rat hepatoma H-4-IIE cells in culture by 2,3,7,8-tetrachlorodibenzo-p-dioxin and related compounds: mechanistic studies using radiolabeled congeners.

Treatment of rat hepatoma H-4-IIE cells in culture with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PeCDD), 1,2,3,7,8-pentachlorodibenzofuran (PeCDF), 1,2,7,8-TCDF, and 2,3,7-trichlorodibenzo-p-dioxin (TrCDD) resulted in the structure-dependent induction of aryl hydrocarbon hydroxylase and ethoxyresorufin O-deethylase activities. The induction potencies followed the order 2,3,7,8-TCDD greater than 2,3,7,8-TCDF greater than 1,2,3,7,8-PeCDD approximately 1,2,3,7,8-PeCDF greater than 1,2,7,8-TCDF greater than 2,3,7-TrCDD and were comparable to structure-toxicity relationships which have previously been reported. In contrast, many of the properties of these compounds were structure-independent. For example, using tritiated congeners of high specific activity (greater than 30 Ci/mmol) the sedimentation coefficients (S) for the nuclear and cytosolic aryl hydrocarbon (Ah) receptor complexes were 5-6 and 9-10 S, respectively, for all the radioligands. Moreover, examination of the processing of nuclear Ah receptor complexes for the radiolabeled congeners showed that after 6 h, the rates of nuclear processing were very low and varied between 0.006 and 0.0385 fmol degraded/mg protein/mg total DNA. These results were consistent with the reported stability and persistence of the nuclear Ah receptor complexes and in addition, there were no apparent structure-dependent differences in the processing rates. Inspection of the nuclear receptor levels and the corresponding induced enzyme activities for the congeners showed that there was a linear correlation between average nuclear receptor complex levels (18-42 h) and induced enzyme activities (32-42 h) for all six radioligands; these data indicated that the rates of cytochrome P450-dependent gene expression correlated with the levels of nuclear Ah receptor complex. In contrast, the accumulation of occupied nuclear receptor complexes in rat hepatoma H-4-IIE cells was structure-dependent and appeared to be one of the factors which governed the observed structure-induction and the previously reported structure-toxicity relationships for 2,3,7,8-TCDD and related halogenated aryl hydrocarbons.

Animals↗
PubMed1989

2,2',4,4',5,5'-hexachlorobiphenyl as a 2,3,7,8-tetrachlorodibenzo-p-dioxin antagonist in C57BL/6J mice.

At doses as high as 750 to 1000 mumol/kg, 2,2',4,4',5,5'-hexachlorobiphenyl (HCBP) did not cause fetal cleft palate, suppress the splenic plaque-forming cell response to sheep red blood cells, or induce hepatic microsomal ethoxyresorufin O-deethylase (EROD) in C57BL/6J mice. Despite the lack of activity of HCBP in eliciting any of these aryl hydrocarbon (Ah) receptor-mediated responses, competitive binding studies indicated that HCBP competitively displaced 2,3,7,8-[3H]tetrachlorodibenzo-p-dioxin (TCDD) from the murine hepatic cytosolic receptor. Cotreatment of C57BL/6J mice with TCDD (3.7 nmol/kg) and HCBP or 4,4'-diiodo-2,2',5,5'-tetrachlorobiphenyl (I2-TCBP) (400 or 1000 mumol/kg) showed that both compounds partially antagonized TCDD-mediated cleft palate and immunotoxicity (i.e., suppression of the splenic plaque-forming cell response to sheep red blood cells), and HCBP antagonized TCDD-mediated hepatic microsomal EROD induction. Thus, HCBP and I2-TCBP, like the commercial polychlorinated biphenyl mixture Aroclor 1254, were partial antagonists of TCDD action in C57BL/6J mice; however, it was also apparent from the results that Aroclor 1254 was the more effective antagonist at lower doses. Using [3H]TCDD, it was also shown that some of the effects of HCBP on TCDD-mediated cleft palate may be due to the decreased levels of TCDD found in the fetal palates after cotreatment with TCDD and HCBP. 4,4'-[125I2]diiodo-2,2',5,5'-tetrachlorobiphenyl ([125I2]TCBP) of high specific activity (3350 Ci/mmol) was synthesized and used to investigate the direct binding of this compound to the murine hepatic Ah receptor or other cytosolic proteins. No direct specific binding was observed between 125I2-TCBP and any cytosolic proteins using a sucrose density gradient assay procedure. These results contrasted with previous studies with Aroclor 1254 that suggested that this mixture acted as a competitive Ah receptor antagonist.

Animals↗
PubMed1989

Monoclonal antibody detects embryonic epitope specific for nerve-derived transferrin.

Monoclonal antibodies were generated against transferrin purified from chick embryo extract by fusing spleen cells from BALB/c mice immunized against embryonic transferrin, with myeloma cells. Antibodies produced by the selected hybridoma clones were all type IgG. Twelve clones were selected for secretion of antibodies to the embryo extract-derived transferrin, and three clones were studied extensively. Immunoblotting was used to demonstrate antibody binding to several avian transferrin proteins derived from adult chicken serum, adult chicken peripheral nerves, and ovotransferrin. Screening and detailed epitope analysis were accomplished by solid-phase immunoassay. The results indicated that two clones, 2G9.1 and 2B11.1, recognized the embryonic and egg antigens in preference to the adult proteins. However, a third clone, 6H2.1, recognized the nerve-derived transferrin preferentially to both the embryonic and adult serum antigens. None of the clones recognized the serum-derived transferrin in preference to the other antigens. These results indicate that embryonic epitope(s) are conserved in the nerve- but not the serum-derived transferrin. They also show that the neural antigen has site(s) distinct from the embryonic proteins. No changes in displacement curves were observed after these proteins were digested with neuraminidase, indicating that the epitope differences discovered are not intimately related to sialic acid residues on the various transferrins.

Animals↗