PubMed Health⌕ Search

Biomedical subjects

M A Parsons

Publications and source records attributed to M A Parsons.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Aggressive toxoplasma retinitis.

Toxoplasma infection is a common cause of infectious uveitis. It usually produces a characteristic fundal appearance, with evidence of previous inflammation. However, it may occur in an atypical and aggressive form. Steroids administered to salvage vision may then worsen the clinical course. Retinal biopsy may be diagnostic in cases where doubt exists. We illustrate these points with two cases.

Aged↗
PubMed1992

Congenital adenoma of the iris and ciliary body: light and electron microscopic observations.

A 23-year-old man had a lesion in the right inferior iris which appeared to have enlarged since it was first seen when the patient was aged 5 years. The lesion was excised by a partial iridocyclectomy. Histopathologically the neoplasm was composed of both pigmented and non-pigmented cells. Pseudoacini, containing acid mucopolysaccharides, were present throughout the tumour matrix. Electron microscopically the non-pigmented cells were found to possess a convoluted plasmalemma, abundant rough endoplasmic reticulum, and numerous desmosomes and gap junctions. The pigmented cells contained large, round, mature melanosomes, occasional premelanosomes, and desmosomes, which resembled the posterior pigment epithelium of the iris. The intercellular matrix contained fine collagen fibrils resembling vitreous. We believe that this neoplasm represents a congenital adenoma of the ciliary body and iris.

Adenoma↗
PubMed1992

Factors which influence necropsy requests: a psychological approach.

AIMS: To determine which factors influence a clinician's decision to request a necropsy. METHODS: Patient age, confidence in premortem diagnosis, relatives' attitudes, and conditions of necropsy practice were combined factorially (two levels each) in separate medical and surgical questionnaires based on clinical case histories. The interactions between the factors were measured by a repeated measures factorial analysis of variance for each of the two clinical groups. The influence of the clinician's interest in necropsies on these interactions was also examined by a similar method. RESULTS: Necropsies were more likely to be requested on young patients, when diagnostic confidence was low, and when relatives' attitudes were favourable. Conditions of necropsy practice did not affect the likelihood of a request and there was no apparent overall difference in necropsy requests between the two groups of clinicians. The "patient age" and "relatives" factors had less influence on the decision of the surgical group to request necropsy. This was attributed to the opportunity to "see for themselves" at operation and was supported by the finding that surgeons were very likely to request necropsies in the absence of surgical intervention. Clinicians from both groups with a high pre-existing interest in the necropsy were consistently more likely to request necropsies. CONCLUSIONS: The "case history" based questionnaires successfully measured the relative influence of multiple factors in relation to the decision of clinicians to request a necropsy. These findings suggest that any attempt to reverse the decline in necropsy rates should focus on changing the clinician's perception of the value of the modern necropsy.

Age Factors↗
PubMed1992

Gelatinolytic metalloproteinase secretion patterns in ocular melanoma.

Fifteen posterior uveal melanoma cell lines were analyzed qualitatively for gelatinolytic and caseinolytic proteinase activity after one to five in vitro passages. All 15 cell lines secreted a gelatinolytic metalloproteinase, with an apparent molecular weight of 72 kD, into protein-free culture media; nine of these secreted an additional gelatinolytic metalloproteinase with an apparent molecular weight of 92 kD. Neither species had the ability to degrade casein. This approach may provide insight into the mechanisms of tumor metastasis in uveal melanoma.

Aged↗
PubMed1992

Mucinous sweat-gland adenocarcinoma of the eyelid.

A case of mucinous sweat-gland adenocarcinoma of the eyelid, clinically diagnosed as a cyst, is presented. This lesion, although accounting for a small proportion of all sweat gland tumors, has a predilection for the eyelid. It is locally aggressive, has metastatic potential, and wide local excision is recommended as the primary procedure. This case illustrates the clinical, macroscopic, and histopathological features of a rare primary malignancy of the eyelid.

Adenocarcinoma↗
PubMed1989

The ultrastructural pathological features of congenital microcoria. A case report.

We describe the light microscopic, immunohistochemical, and electron microscopic findings in a sporadic case of congenital microcoria in a 72-year-old man with senile cataract. We demonstrated a lack of myofilaments and desmin in the stromal cytoplasmic processes of the anterior pigmented cells of the iris, although other features of muscle differentiation were present in these few surviving cell processes that normally form the pupil dilator muscle. Degenerative changes in anterior pigment cells and iris stromal atrophy were thought to be late secondary features of microcoria. The findings suggest that congenital microcoria results from a defect of intermediate filaments in the terminal fetal stages of differentiation of the anterior pigmented epithelial cell of the iris, with absence of myofilaments and consequent failure of development of a functional dilator pupil muscle.

Aged↗
PubMed1989

Carrier detection and prenatal diagnosis in Norrie disease.

We report the use of DNA probes to determine carrier status in three young women from a large kindred with Norrie disease. One of the women requested prenatal diagnosis during pregnancy. In this pedigree, Norrie disease was not characterized by a deletion at DXS7.

Blindness↗