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Biomedical subjects

M A Parsons

Publications and source records attributed to M A Parsons.

At least 19 recordsLinked to original sources
PubMed1995

Involvement of anterior chamber angle structures in disseminated histoplasmosis: report of three cases.

This study describes the involvement of anterior chamber (AC) angle structures in patients with disseminated histoplasmosis. The postmortem eyes from three patients (aged 33, 41, and 42 years, respectively) with disseminated histoplasmosis, two of whom had acquired immunodeficiency syndrome, were examined by light microscopy using hematoxylin-eosin, periodic acid-Schiff (PAS), and Gomori's methenamide silver (GMS) stains. Electron microscopy studies of the choroid were performed in one eye. Significant numbers of budding yeast forms of Histoplasma capsulatum measuring 2-5 microns in diameter were observed within the trabecular meshwork, Schlemm's canal and in the deep intrascleral plexuses. All eyes showed massive involvement of the choroidal vasculature, including the choriocapillaris. The organisms were observed freely as well as in small clusters within the cytoplasm of circulating monocytes. The vessels of the limbal conjunctiva (two eyes) and ciliary body (three eyes) contained many Histoplasma organisms. In one eye, several budding yeast were noted in an iris vessel and in occasional histiocytes within the ciliary muscle. Blood smears containing Histoplasma organisms were observed in two cases. None of the patients had an ophthalmologic examination prior to death. Involvement of the intravascular structures of the eye as well as the AC angle was observed in three patients with disseminated histoplasmosis. The fungus most likely reached the AC angle structures by direct hematogenous dissemination or via the aqueous humor by migration from vessels in the ciliary body and iris. An abnormal retrograde blood flow into the AC angle structures may have also played an important role. We suggested that the intraocular pressure be monitored in cases of suspected disseminated histoplasmosis to detect functional alterations indicative of a blockage in the outflow channels.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Xanthogranulomatous cholecystitis.

Clinical, radiological and pathological findings in 31 patients with xanthogranulomatous cholecystitis have been reviewed. The spectrum of presentation was similar to that of cholelithiasis but fewer patients had biliary colic (17 per cent) and there were more complications (32 per cent). Four patients had a biliary fistula and four a perforated gallbladder with abscess formation. Patients characteristically had gallstones. Appearances often mimicked carcinoma of the gallbladder at ultrasonography and/or laparotomy, with xanthogranulomatous tissue extending to adjacent structures. Xanthogranulomatous cholecystitis and carcinoma of the gallbladder coexisted in three patients. The possibility should be considered that an 'inoperable tumour' of the gallbladder may in fact be xanthogranulomatous cholecystitis, a benign condition that frozen-section biopsy may confirm.

Adult↗
PubMed1994

Primary sebaceous carcinoma of lacrimal gland: a previously unreported primary neoplasm.

We describe a patient who presented with a rapidly growing neoplasm of the lacrimal gland which histologically was a sebaceous gland carcinoma. The eyelid was entirely normal on examination under anaesthesia. Sebaceous differentiation has been described on only three previous occasions, arising within pre-existing tumours of the lacrimal gland such as pleomorphic adenoma. In this case there is a single tumour cell line within normal lacrimal gland, and the eyelid is normal. This points to a previously unreported diagnosis of primary sebaceous carcinoma of the lacrimal gland.

Adenocarcinoma, Sebaceous↗
PubMed1994

Factors influencing physical activity in average-weight and overweight young women.

Young women are a specific population that is falling short of performing what is considered to be an optimal level of physical activity. The purpose of this study was to determine the ability of nine explanatory variables to predict physical activity in a sample of average-weight (n = 225) and overweight (n = 115) young women. Personal control, race, regular participation in organizations and groups, and interpersonal support were the significant predictors of physical activity in overweight women. For average-weight women, only three variables--personal control, regular participation, and race--were significantly related to physical activity. Recreational activity was routinely performed by 25% of the women. Of the 14% who reported regular vigorous physical activity, 26% were White and 10% were Black. The findings suggest that nurses in community settings design interventions that are sex and race specific and that include personal-control skill building, interpersonal support systems, and multiple forms of physical activity, particularly recreational forms.

Adolescent↗
PubMed1994

Effect of melanocyte stimulating hormone on human cultured choroidal melanocytes, uveal melanoma cells, and retinal epithelial cells.

PURPOSE: To establish methodology for the culture of human choroidal melanocytes to compare their responsiveness to melanocyte stimulating hormone (MSH) with that of their transformed melanoma counterparts and with that of the retinal epithelial cell. METHODS: Choroidal melanocytes from the choroid of eyes enucleated for the presence of malignant melanoma were cultured in MCDB 153 medium supplemented with insulin, transferrin, hydrocortisone, glutamine, nystatin, vitamin E, phorbol myristate acetate, bovine hypothalamic extract, cholera toxin, and chelexed fetal calf serum. RESULTS: High yields of pure spindle-shaped bipolar melanocytes were obtained with a doubling time of 3 to 4 days in nine consecutive eyes. Cells continued to divide after 4 months in culture. In contrast, uveal malignant melanoma cells grew rapidly in a relatively simple medium of Ham's F12:DMEM (1:1) supplemented with fetal calf serum, insulin, transferrin and glutamine. This medium was unable to support choroidal melanocytes. Choroidal melanocytes were DOPA-positive with appreciable tyrosinase activity that significantly increased with treatment with MSH. MSH also significantly altered the size, local density, and distribution of primary and mature melanosomes of ocular melanocytes. In contrast, uveal melanoma cells had a low level of tyrosinase activity and failed to respond to MSH with either an increase in enzyme activity or melanosome size. Retinal epithelial cells failed to show significant tyrosinase activity under the conditions studied or any increase in melanosome size in response to MSH. CONCLUSION: Ocular melanocytes show evidence of regulation by MSH and a range of mitogenic stimuli unlike the transformed melanoma cells, implying a loss of regulatory control in the latter.

Animals↗
PubMed1993

Eastern equine encephalitis virus in Ohio during 1991.

During August and September of 1991, an epizootic of eastern equine encephalitis (EEE) virus in horses occurred in Wayne and Holmes countries, OH. This was the first recorded epizootic of EEE virus in the state. Twelve horses were confirmed positive for EEE virus through virus isolation or seroconversion, and seven additional horses with compatible symptoms were in close spatial and temporal proximity to the confirmed cases and were presumed to have died from EEE virus. The outbreak was centered around the Killbuck Wildlife Area, a 2,147-ha tract maintained by the state, half of which consists of wooded swamp and marsh. Mosquitoes were collected in upland areas before the epizootic and in the swamp basin at the end of the epizootic to identify the mosquito species involved in EEE virus transmission. We collected and tested 22,095 specimens for the presence of virus. EEE virus was isolated from one pool of the most likely epizootic vector, Coquillettidia perturbans (Walker). The minimum infection rate for EEE virus in this species was 0.1/1,000. Dense populations of Aedes vexans (Meigen) and Culex salinarius Coquillett occurred in the area, but their densities peaked after the epizootic. It is unlikely that these species were involved in epizootic transmission. IgM antibody to EEE virus was detected in three bird species collected in the swamp.

Animals↗
PubMed1993

Improving school nursing practice in South Carolina through continuing education.

School nurses often provide direct health care to school-age children, and thus need a range of knowledge and skills to meet the needs of less healthy children, as well as healthy children. To meet this challenge in South Carolina, a statewide continuing education program with didactic and school-based clinical instruction was implemented to enhance the scope of school nurse practice. The physical, psychosocial, and environmental health dimensions of the school nurse's role improved significantly when the program ended at nine months and were maintained at 18 months follow-up. However, program management skills did not improve. Practice guidelines indicate continuing education can improve practice in areas under direct control of the school nurse. Focus on development of program management skills is called for in continuing education. Redefinition of this aspect is crucial to full development of the school nurse role and improved health for school-age children.

Adult↗
PubMed1993

Ocular involvement in mycosis fungoides.

A case of mycosis fungoides with bilateral intraocular involvement is reported. The diagnosis was established with the aid of a vitreous biopsy. Intraocular involvement, though rare, may be an early sign of extracutaneous disease.

Eye Neoplasms↗
PubMed1992

Non-random abnormalities of chromosomes 3, 6, and 8 associated with posterior uveal melanoma.

We present ten cases of posterior uveal melanoma which were karyotyped after short-term culture. One tumour had a normal chromosome complement. The remaining nine tumours were cytogenetically abnormal, with chromosomes 3, 6, 8, 11, and 13 most frequently involved. Abnormalities of chromosome 13 were seen in two cases, chromosome 11 in three cases, and chromosomes 3, 6, and 8 in five cases. Four tumours, all derived from the ciliary body, demonstrated monosomy 3 and i(8q), confirming the involvement of these aberrations with a subgroup of uveal melanomas arising from the ciliary body.

Aged↗
PubMed1992

C-myc oncogene expression in ocular melanomas.

We have investigated the expression of c-myc in 24 ocular melanomas by immunohistochemistry, using two monoclonal antibodies raised against a mid-sequence portion of the c-myc product (6E10) and against the C-terminus (9E10). The results were compared with other putative prognostic factors, including tumour size, cell type, proliferation index (determined by flow cytometry), and ploidy, as well as immunohistochemical staining for HMB-45 and S-100 antigens. Staining, often focal, for c-myc was found in both the nucleus and the cytoplasm of a proportion of the cells in most tumours studied. Total cell staining for myc protein correlated with proliferative index in diploid tumours; seven out of nine aneuploid and mixed aneuploid/diploid cells showed strong staining in at least one cellular compartment. A positive correlation with myc expression was also found for HMB-45 staining, but not for cell type or staining for S-100. The results support the hypothesis that myc protein is involved in cellular proliferation in uveal melanomas and indicate that immunohistochemistry for myc antigen may be a useful prognostic marker in these tumours.

Adult↗
PubMed1992

The ocular pathology of Norrie disease in a fetus of 11 weeks' gestational age.

The ocular pathology of Norrie disease was studied for the first time in a fetus of 11 weeks' gestation, following prenatal diagnosis using genetic markers for Norrie disease and elective abortion. The eyes were histologically normal, with no evidence of primary neuroectodermal maldevelopment of the retina, previously postulated to be the cause of the ocular changes. We believe that the retinal and other manifestations of Norrie disease are the result of a primary abnormality of vascular proliferation, probably in relation to persistent hyperplastic primary vitreous after approximately 14 weeks' gestation. We postulate that the ocular and otological effects of Norrie disease may be due to a genetically mediated abnormality of secretion of, or sensitivity to, angiogenic growth factors at endodermal-neuroectodermal interfaces during fetal and postnatal development.

Abortion, Legal↗
PubMed1992

The pituitary in cirrhosis: ultrastructure, growth hormone, and prolactin concentrations.

Micronodular cirrhosis was induced in male SUAH substrain Wistar rats by combined phenobarbitone and carbon tetrachloride treatment. Both pituitary and serum concentrations of growth hormone were significantly reduced in cirrhotic rats compared with age-related untreated rats or those treated only with phenobarbitone. Ultrastructurally growth hormone-secreting cells (somatotrophs) of pituitaries of cirrhotic rats appeared relatively inactive, having few hormone-containing granules, sparse rough endoplasmic reticulum, and small nuclei with areas of condensed chromatin. The cells themselves were smaller than similar cells of untreated rats with a reduced cytoplasmic area. In addition immunocytochemistry of pituitaries at light microscope level, using sheep anti-rat growth hormone antibody, showed that somatotrophs of cirrhotic rats were more heteromorphic and disorganized than those in controls. There was marked development of the folliculo-stellate cell system in pituitaries of cirrhotic rats, the cells were enlarged with distinct golgi, and numerous microvilli were projecting into dilated follicular lumena.

Animals↗
PubMed1992

Cutaneous xanthogranulomatous inflammation: a potential indicator of internal disease.

Cutaneous xanthogranulomatous inflammation is usually regarded as a primary disease process. We describe two patients with xanthogranulomatous pyelonephritis and nephro-cutaneous fistulae, one patient with xanthogranulomatous cholecystitis and a chole-cutaneous fistula and one patient with xanthogranulomatous appendicitis and appendiceal-cutaneous fistula. After the first case, awareness that cutaneous xanthogranulomatous inflammation can be secondary to related internal disease played a vital diagnostic role in the subsequent cases.

Aged↗
PubMed1992

Circulating prostate specific antigen-positive cells correlate with metastatic prostate cancer.

Analytical flow cytometry was used to study circulating prostate specific antigen (PSA)-positive cells in 40 consecutive patients with newly diagnosed, untreated prostate cancer; 25 patients (63%) had metastatic disease confirmed by a positive bone scan. Cell suspensions were prepared for each patient from both the primary tumour and peripheral blood samples. The cells were stained with a monoclonal antibody against PSA, and analysed by flow cytometry; PSA-positive cells were sorted according to their immunofluorescence and light scatter properties. The cellular deoxyribonucleic acid (DNA) content of each specimen was also analysed to establish ploidy status. PSA-positive cells were detected in the peripheral blood of 33 patients (83%). The presence of these cells in the circulation showed a higher degree of sensitivity and specificity in predicting positive bone scans than did serum PSA levels. Circulating PSA-positive cells may represent either a subpopulation of tumour cells with distinct metastatic properties or, alternatively, host immunocytes which take up PSA in an active or passive manner.

Aged↗