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D T Shum

Publications and source records attributed to D T Shum.

31 records · Page 2Linked to original sources
PubMed1990

Usefulness of immunoperoxidase staining with high-molecular-weight cytokeratin in the differential diagnosis of small-acinar lesions of the prostate gland.

There are a number of benign, small-acinar lesions in the prostate gland that may be difficult to differentiate from small-acinar adenocarcinoma. An important diagnostic criterion in this differentiation is the loss of the basal layer in small-acinar adenocarcinoma and its preservation in benign conditions. A monoclonal antibody to high-molecular-weight cytokeratins (34 beta E12) has been shown to stain these basal cells preferentially. To assess the usefulness of this antibody in distinguishing benign from malignant small-acinar lesions, we examined 21 cases of small-acinar adenocarcinoma and 47 examples of benign lesions, which included atypical adenomatous hyperplasia, atrophy, post-sclerotic hyperplasia, basal cell hyperplasia, and fibroepithelial nodule. Positive staining with 34 beta E12 was seen in 13/13 cases of atypical adenomatous hyperplasia, although in some cases the staining was weak and focal. Positivity with 34 beta E12 was also demonstrated in all other benign lesions studied. All 21 cases of small-acinar adenocarcinoma showed no reactivity with 34 beta E12. The results suggest that 34 beta E12 is of value in distinguishing between well-differentiated, small-acinar prostatic adenocarcinoma and its mimics. However, care is needed in interpretation of staining in formalin-fixed material due to the variable reactivity, particularly in cases of atypical adenomatous hyperplasia.

Adenocarcinoma↗
PubMed1988

Histogenesis of Dupuytren's disease: an immunohistochemical study of 30 cases.

Thirty-seven specimens from the hands of 30 patients with Dupuytren's disease were examined by light microscopy after immunohistochemical staining for the presence of desmin intermediate filaments. Results indicated that desmin-positive cells were present in the proliferative Dupuytren's nodules, and that the number of desmin-positive cells decreased significantly in the fibrous phase of the disease. Also, on the basis of the pattern of distribution of the desmin-positive cells around vessels, we postulate that the desmin-positive cells in Dupuytren's nodules were migrating perivascular smooth muscle cells from the vessel wall. The exact fate of these cells is uncertain, but we hypothesize that these displaced perivascular smooth muscle cells are capable of transforming into collagen-producing, desmin-negative myofibroblasts that form the cellular basis of Dupuytren's lesions.

Adult↗
PubMed1987

Transitional cell carcinoma in the Muir-Torre syndrome.

The association of multiple sebaceous neoplasms and visceral malignancies is known as the Muir-Torre syndrome. We describe a patient who had papillary transitional cell carcinoma of the right renal pelvis resected in 1981 and papillary transitional cell carcinoma of the left renal pelvis removed surgically in 1983. Recurrent transitional cell carcinoma necessitated further resection of tumor in the right renal pelvis in 1983, right nephrectomy and partial ureterectomy in 1984, and removal of the right ureteral stump in 1985. History included multiple seborrheic keratoses, a keratoacanthoma and 4 sebaceous carcinomas between 1968 and 1985. In 1971 partial colectomy and jejunectomy were performed for stage D (Duke classification) adenocarcinoma of the transverse colon. Despite this the patient remains alive and well with no evidence of residual or metastatic disease. The Muir-Torre syndrome is a subtype of the cancer family syndrome, with gastrointestinal tract tumors being the most frequent visceral malignancies. Urinary tract carcinomas are present in just more than 10 per cent of the cases. This entity is discussed and the literature is reviewed with emphasis on the urological associations.

Aged↗
PubMed1986

The value of nuclear contour index in the diagnosis of mycosis fungoides. An assessment of current ultrastructural morphometric diagnostic criteria.

Skin biopsy specimens from 43 patients with established mycosis fungoides (MF) and 28 with non-MF lymphoid skin infiltrations were studied by transmission electron microscopy. The nuclear contour index (NCI) of infiltrating lymphoid cells was obtained by means of a Zeiss Videoplan computer and measuring tablet. Classification of the material into MF and non-MF groups was done according to the diagnostic criteria used by McNutt et al. (1980, 1981) and Meijer et al. (1980); this study evaluates the usefulness of these previously published criteria based on quantitative electron microscopy. Statistical analysis confirmed that the mean NCI (MNCI) of the lymphoid cells of patients with MF is significantly greater than that in patients with other lymphoid infiltrates (P less than 0.001). However, all published diagnostic criteria (McNutt et al., 1980, 1981, and Meijer et al., 1980) tested in the authors' larger patient population yielded lower sensitivity than has been reported. The diagnostic criteria based on values of MNCI, percentage of lymphoid cells with NCI greater than 7, and percentage of lymphoid cells with nuclear profile area of greater than 30 microns2 reported by McNutt et al. (1981) appear to be better than others, and provide the highest sensitivity rate, which is in the range of 44% to 47%. There were no false-positive findings. It was concluded that the use of ultrastructural morphometry according to the techniques and diagnostic criteria of McNutt et al. (1981) is useful in the diagnosis of MF.

Adolescent↗
PubMed1986

Metastatic tumours of the testes.

Metastatic tumours of the testes are uncommon, making up little more than 2% of all testicular neoplasms. The most frequent primary sites are the lung and prostate. Only rarely do these lesions present clinically either as the first sign of malignant disease or as a complicating factor during the course of known disease. The authors present two cases illustrating both of these occurrences. The first, a man with carcinoma of the common bile duct, initially had a mass in the testicle and the second, a patient with carcinoma of the prostate, had his clinical course complicated by a symptomatic metastasis to the right testis. The authors also reviewed their local autopsy experience and identified 16 more cases. Metastases were grossly visible in 38% (6 of 16). The most frequent primary sites were lung (four cases), stomach (four) and prostate (three). Routes of spread as well as possible explanations for the low incidence are discussed.

Adenocarcinoma↗
PubMed1982

Stimulation of monocyte production by an endogenous mediator induced by a component from Listeria monocytogenes.

A monocytosis-producing activity (MPA) is present in a saline-extractable material (SE) from Listeria monocytogenes. The mechanism of stimulation of monocyte production by SE was studied. Serum obtained from mice at appropriate times after injection of SE induced monocytosis in normal recipients. The monocytosis-inducing activity present in serum differed from SE with respect to timing of the monocytosis, fractionation pattern on a Sephadex G-200 column, and thermolability. The minimum dose of SE capable of producing a monocytosis was 100 micrograms. Antibody to SE capable of detecting SE at a concentration of greater than 5 micrograms/ml failed to detect SE in samples of active serum. Therefore it seemed highly unlikely that activity in serum was due to the presence of trace amounts of SE. The activity present in serum was thermolabile and had a molecular weight of about 38,000. The data are consistent with the hypothesis that injection of SE caused the production or release of an endogenous mediator capable of stimulating monocytosis.

Animals↗
PubMed1979

Stimulation of monocyte precursors in vivo by an extract from Listeria monocytogenes.

A water-soluble monocytosis-producing activity (MPA) extracted from Listeria monocytogenes was found to stimulate proliferation of promonocytes in vivo. Mice were pulse-labelled for 2 h with tritiated thymidine ([3H]TdR) at various times after intraperitoneal injection of MPA. Autoradiography of bone marrow cells revealed an increased labelling index of promonocytes of MPA-treated mice which was maximum 8 h after the MPA injection. Mice labelled with [3H]TdR 8 h after MPA injection developed a monocytosis at the expected time (peak at 48 h) and the blood monocytes were found to be highly labelled. Both the generation time of monocyte precursors and the halftime of blood monocytes were found to be shorter than the corresponding values in control mice.

Animals↗
PubMed1979

Immunological properties of partially purified material with monocytosis-producing activity from Listeria monocytogenes.

A fraction rich in a monocytosis-producing activity (MPA) has been obtained by a two-stage chromatographic separation from a saline extract (SE) of Listeria monocytogenes. Like SE, the purified material elicits monocytosis and decreases the halftime of circulating monocytes. The purification of MPA eliminates the following found in SE: the in vitro mitogenic activity, the in vitro adjuvant activity, the immunosuppressive activity, and the granulocytosis-promoting and the lymphopenia-inducing activities.

Animals↗
PubMedDate not supplied

Microscopic acanthosis nigricans in type 2 diabetes.

BACKGROUND: Acanthosis nigricans (AN) has been associated with insulin resistance. Individuals with type 2 diabetes are insulin-resistant and, therefore, could be expected to manifest AN. However, the prevalence and predictors of AN are unknown in this population. OBJECTIVE: An outpatient population with Type 2 diabetes (DM) was compared with matched controls (C) for microscopic and clinical AN along with measurement of body habitus, insulin, glucose, and androgen levels. METHODS: Twenty-four individuals with DM (12M, 12F) from a tertiary care center were compared with 24 C (12M, 12F). Fasting glucose, insulin, sex hormone binding globulin, androstenedione, dihydroepiandrosterone sulfate, and testosterone were measured. Height, weight, waist/hip measures, and a clinical survey for acanthosis were recorded. A 2-mm skin biopsy from midaxilla of the nondominant arm was taken for pathological review. RESULTS: C and DM were matched for age and body mass index (BMI). Prevalence of microscopic AN in C was 12% (3/24) and in DM was 21% (5/24; NS). In C, AN was predicted by waist, waist/hip ratio, and fasting insulin measures, while none of the variables examined was predicative of AN in DM. CONCLUSIONS: Microscopic acanthosis nigricans was found in similar numbers of people with DM when compared with C. Fasting insulin levels most strongly predicted the presence of AN in C, while no significant predictors of AN were found in the population with DM.

Acanthosis Nigricans↗
PubMedDate not supplied

Choriocarcinoma metastatic to the lung. A cytologic study with identification of human choriogonadotropin with an immunoperoxidase technique.

A case of choriocarcinoma metastatic to the lung following a previous hydatidiform mole is presented. It was possible to make definitive identification of trophoblastic elements on a needle aspiration biopsy using an immunoperoxidase staining technique, thus avoiding diagnostic thoracotomy prior to therapeutic intervention. A method of immunoperoxidase staining of previously fixed and Papanicolaou-stained needle aspiration biopsy specimens is also described, and other uses of the immunoperoxidase technique on needle biopsy specimens are discussed.

Adult↗