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Biomedical subjects

K Cooper

Publications and source records attributed to K Cooper.

At least 91 records · Page 5Linked to original sources
PubMed1997

Weight dissatisfaction and weight loss attempts among Canadian adults. Canadian Heart Health Surveys Research Group.

OBJECTIVE: To describe the pattern of weight dissatisfaction and weight loss attempts among Canadian adults and the reasons for and methods of weight loss among those trying to lose weight. DESIGN: Population-based, cross-sectional surveys. SETTING: Ten Canadian provinces between 1986 and 1992. PARTICIPANTS: A probability sample of 29,855 men and women aged 18 to 74 years was selected using provincial health insurance registration files; this paper describes the subsample of 19,841 (66%) participants from whom anthropometric data were collected. OUTCOME MEASURES: Discrepancy between actual and desired body mass index (BMI); attempts to lose weight; reasons for losing weight; methods of weight loss used. RESULTS: Whether their weight was in the acceptable range (BMI 20-24 kg/m2) or at a level of increasing risk (BMI > or = 27 kg/m2), women were more likely than men to wish they weighed less and to be trying to lose weight; almost two-thirds of women but less than half the men with BMI > or = 27 kg/m2 were trying to lose weight. Even among those with BMI 20-24 kg/m2, 32% of women (v. 10% of men) were trying to reduce their weight. Weight dissatisfaction and current and past weight loss attempts were all negatively associated with age among women, but were unrelated to age among men. People with higher ratios of waist to hip circumference (WHR), controlling for BMI, were no more likely to be trying to lose weight than those with lower WHR; in fact, for women with BMI 27-29 kg/m2, WHR was negatively associated with prevalence of weight loss attempts. The presence of diabetes, hypertension and hypercholesterolemia was also unrelated to weight loss attempts; regular smokers and sedentary people were less likely to report trying to lose weight, controlling for BMI. Among those currently trying to lose weight, the most commonly mentioned reason was to improve general health, followed by increasing attractiveness. Overall, the most frequently mentioned method of weight loss was dieting, followed by exercise. CONCLUSIONS: Substantial numbers of men whose BMI places them at increased health risk appear to be content with their weight and are not attempting to reduce it. Conversely, women, especially the young and middle-aged, are likely to consider themselves above their desired weight and to be trying to lose weight, even when their weight is within acceptable limits. This reinforces the need to consider differences between men and women in efforts to promote and support healthy weights among Canadians.

Adult↗
PubMed1997

Attitudes toward environmental hazards: where do toxic wastes fit?

The public is continually faced with making decisions about the risks associated with environmental hazards, and, along with managers and government officials, must make informed decisions concerning possible regulation, mitigation, and restoration of degraded sites or other environmental threats. We explored the attitudes regarding several environmental hazards of six groups of people: undergraduate science majors, undergraduate nonscience majors, and graduate students in environmental health, in ecological risk assessment, and in nonscience disciplines, as well as nonstudents over 35 yr of age. We had predicted that there would be significant differences in attitudes between science and nonscience majors and as a function of age. Relative concerns could be divided into three discrete classes (in descending order of concern): (1) general ecological problems (cutting tropical forests, polluting groundwater, trash along the coasts, lead in drinking water, and acid rain), (2) radon and nuclear wastes, and finally (3) specific nuclear waste facilities, chromium, fertilizers and pesticides, and electromagnetic waves. For any hazard, attitudes were consistent across groups with regard to ranking the severity of the environmental problem and willingness to expend funds to solve the problems. Attitudes about spending money to develop methods to evaluate risk fell in the middle level of concern. There were no major differences among classes of college-age students, or between them and older nonstudents.

Adult↗
PubMed1997

Follicular dendritic cell sarcoma. Clinicopathologic analysis of 17 cases suggesting a malignant potential higher than currently recognized.

BACKGROUND: The goal of this study was to characterize the clinicopathologic features of follicular dendritic cell sarcoma, a very uncommon neoplasm. METHODS: The 17 cases were collected from the consultation and surgical pathology files of the authors, including 8 previously reported cases. The histologic and immunohistochemical features and outcome were analyzed. RESULTS: The patients had a median age of 40 years, with a slight female predominance. Seven patients presented with enlarged lymph nodes, and ten presented with tumor in extranodal sites. Two cases were associated with hyaline-vascular Castleman's disease. The tumors had an average greatest dimension of 6.7 cm. The most common histologic feature was a storiform or fascicular array of spindle, ovoid, or polygonal cells with oval nuclei, delicate nuclear membrane, vesicular or granular chromatin, distinct nucleoli, indistinct cell borders, and frequently fibrillary cytoplasm. There were often scattered multinucleated forms. The tumor cells sometimes formed sheets, circular whorls, follicle-like structures, trabeculae, or pseudovascular spaces. There was a sprinkling of small lymphocytes, with or without cuffing around blood vessels. The neoplastic cells were immunoreactive for CD21 (17 of 17 cases), CD35 (17 of 17 cases), desmoplakin (10 of 17 cases), epithelial membrane antigen (14 of 16 cases), S-100 protein (6 of 17 cases), and CD68 (2 of 17 cases), but not cytokeratin. Ultrastructural studies showed villous processes connected by desmosomes. Only one harbored the Epstein-Barr virus. Among 13 patients with a median follow-up of 3 years, local recurrence occurred in 6, metastasis in 6, and 3 died of disease. CONCLUSIONS: Follicular dendritic cell sarcoma exhibits distinctive histologic features that permit its presumptive recognition, but a firm diagnosis requires confirmation with special studies. Because it has a significant recurrent and metastatic potential (the latter risk having been previously underestimated), it should be viewed as an intermediate grade malignancy. An intraabdominal location is associated with a particularly aggressive clinical course.

Adolescent↗
PubMed1997

bcl-2 and p53 protein expression in follicular lymphoma.

Recent studies have shown bcl-2 to be regulated by p53. Other studies have suggested an inverse relationship between p53 and bcl-2 protein expression in breast and colonic cancers and in a variety of subtypes of non-Hodgkin's lymphoma. This study investigates the relationship between bcl-2 and p53 protein expression and the correlation between these findings and the grade and cell type of follicular lymphomas according to the REAL classification. Paraffin-embedded nodal follicular lymphomas (n = 37) were subjected to bcl-2 and p53 immunohistochemistry on tissue sections using a three-step ABC system. Positive immunostaining for both oncoproteins was scored using a three-tiered scale: +, < 10 per cent cells; ++, 10-50 per cent cells; and ++(+), > 50 per cent cells (< 10 per cent was used as a cut-off to define negative tumours). Ninety-seven per cent (36/37) of follicular lymphomas expressed bcl-2 protein in all three grades, manifesting in the small cell (grade 1) through to the large cell (grade 3). p53 protein expression showed a pattern of increasing immunostaining with progression towards the high-grade follicular lymphoma: grade 1 = 6 per cent (1/16); grade 2 = 48 per cent (10/21); grade 3 = 100 per cent (6/6). Five cases comprised varying combinations of grades. This latter finding suggests a role for p53 mutation in the progression/transformation of follicular lymphoma. The mechanism, however, differs from that suggested in breast and colonic cancers, since an inverse relationship between bcl-2 and p53 was not demonstrated in the present study.

Adult↗
PubMed1997

Electrophysiological effects of Bacillus sphaericus binary toxin on cultured mosquito cells.

The electrophysiological effects of both trypsinactivated native and 42- and 51-kDa cloned binary toxins of Bacillus sphaericus were investigated on cultured Culex quinquefasciatus cells using the patchclamp technique. Rates of reduction in whole-cell membrane resistance were correlated with increasing native toxin concentration. The 42- or 51-kDa cloned toxin alone at 50 micrograms/ml reduced the resistance. Electrophysiological effects occurred before any changes were visible by phase-contrast microscopy.

Animals↗
PubMed1997

Distribution studies in CD-1 mice administered [14C]muconaldehyde.

Trans,trans-muconaldehyde (muconaldehyde, MUC), a microsomal hematotoxic ring-opened metabolite of benzene, has been proposed to play a role in benzene hematotoxicity. In the present study, [14C]muconaldehyde was administered to CD-1 mice and the distribution of [14C]muconaldehyde equivalents was investigated. The study was carried out to evaluate whether [14C]muconaldehyde equivalents could reach the bone marrow. [14C]Muconaldehyde at a dose of 2 mg/kg was administered intraperitoneally (3.4 microCi/mouse) and by intravenous injection (2.7 microCi/mouse). The amount of [14C]muconaldehyde equivalents was measured in the bone marrow, blood, liver, lung, kidney and spleen at 0.25, 0.5, 1, 2, 4, and 24 h after [14C]MUC administration. The results indicate that 0.044% or 0.018% of the total dose administered when given i.v. or i.p., respectively, reached the bone marrow. The elimination of the radioactivity in all organs had at least two phases. The bone marrow, kidney, and lung had a rapid first phase (t1/2 0.5-1.2 h) and a slower second phase (t1/2 2.8-15.7 h). In the liver, a slow first phase (t1/2 3.7 h) was followed by a more rapid second phase (t1/2 1.5 h). The level of radioactivity in blood and bone marrow was significantly higher when [14C]muconaldehyde was administered intravenously compared with intraperitoneally, demonstrating that the route of administration affects the distribution of [14C]muconaldehyde equivalents.

Absorption↗
PubMed1997

Rheumatic Aschoff nodules revisited. II: Cytokine expression corroborates recently proposed sequential stages.

AIMS: A recent immunohistochemical analysis of the Aschoff lesions in rheumatic fever, combining immunohistochemical analysis with comparative morphology, permitted the division of the Aschoff nodules into three stages: (1) Aschoff nodule without admixed lymphocytes, (2) Aschoff nodules with a few T lymphocytes, and (3) Aschoff nodules containing many admixed lymphocytes of both B- and T-cell phenotype. It was postulated that the order of progression was from stage 1 with macrophages only, to accumulation of first T lymphocytes (stage 2) and then B lymphocytes (stage 3). This study was undertaken to determine the role and distribution of interleukin 1 (IL-1), interleukin 2 (IL-2) and tumour necrosis factor alpha (TNF alpha) in the various stages of the rheumatic Aschoff nodule to investigate our hypothesis on the progression of these nodules. METHODS AND RESULTS: Sixteen fresh valve specimens from patients with acute rheumatic fever undergoing valve surgery were obtained. Tissue sections from 14 specimens identified as containing Aschoff nodules were subjected to immunohistochemistry for (1) T and B lymphocytes, to stage the lesions according to our previously proposed criteria; (2) IL-1, IL-2 and TNF alpha; and (3) CD4 and CD8 to phenotype the T lymphocytes. The stage 1 and 2 lesions expressed IL-1 and TNF alpha in the macrophages. The stage 3 lesions showed more variable expression of all three cytokines including IL-2 within T lymphocytes. CONCLUSION: TNF alpha and IL-1 secretion in macrophages is required for T and B lymphocytes activation and aggregation; suggesting that macrophages arrive at the scene of rheumatic injury prior to the lymphocytes. IL-2 is usually expressed later in the inflammatory process and was found only in the lymphoid aggregates. This study therefore produces corroborative evidence for our previously proposed developmental stages of the Aschoff nodule.

Acute Disease↗
PubMed1997

Adenoid cystic carcinoma of the salivary glands: a review of 10 years.

A retrospective analysis was performed of 50 patients with adenoid cystic carcinoma who were seen in the Department of Radiation Oncology, University of Witwatersrand, Johannesburg, South Africa, in the past 10 years. There were 25 men and 25 women with a mean age of 52 years (age range, 21 to 88 years). Five patients had metastatic disease, and 17 had neural invasion. Thirty-four patients had surgery (11, complete; 23, microscopic residual). Sixteen patients had radiotherapy as initial management. The disease-free survival was 26%, overall survival was 29%, and local control was 30% at 10 years. Most recurrences occurred in the first 3 years. Nine patients had metastasis following treatment. The mean survival after metastasis was 15 months. Seven prognostic variables were analyzed using the log-rank test. There was no impact of age, site, type of salivary gland (major vs. minor), tumor stage, node positivity, or neural invasion on disease-free survival, overall survival, or local control. Extent of surgical resection (complete vs. microscopic residual) had a significant impact on disease-free survival and local control (P < 0.05) but no impact on overall survival (P > 0.05) because of the slow-growing nature of these tumors. Similarly, patients who had microscopic residual after surgery and were treated with radiotherapy did better than those who had biopsy and radiotherapy, although this was not significant statistically (P > 0.05). Thus, whenever possible, every attempt must be made to remove all microscopic tumor by surgery. Addition of postoperative radiotherapy with high-energy photons did not improve the locoregional control or survival in our series. There is a place for neutrons in the treatment of adenoid cystic carcinomas in advanced cases of inoperable or recurrent tumors, as a review of literature shows.

Adult↗
PubMed1997

Comparative analysis of biotin intranuclear inclusions of gestational endometrium using the APAAP, ABC and the PAP immunodetection systems.

AIMS/BACKGROUND: Intranuclear inclusions have been observed in gestational endometrial glands. Although resembling Herpes simplex virus infected cells, these nuclei have been shown to contain endogenous biotin. Hence, immunohistochemical systems using the avidin-biotin complex will result in cross reaction and false positivity. This study investigates a series of 10 gestational endometria (formalin fixed and paraffin wax embedded) with intranuclear inclusions using three different immunodetection systems with primary anti-biotin. RESULTS: Both the alkaline phosphatase anti-alkaline phosphatase (APAAP) and peroxidase anti-peroxidase (PAP) systems confirmed that the intranuclear inclusions were endogenous biotin. The streptavidin biotin complex (StreptABC) system produced a positive reaction in both test sections and controls (omitting primary anti-biotin) in the presence of prior blocking with free avidin and biotin. In addition, aberrant immunoreactivity was observed in adjacent nuclei/cytoplasm of endometrial glands and decidualised stroma in the negative control of the PAP system. This was subsequently eliminated using microwave pretreatment prior to immunohistochemistry. CONCLUSION: The use of either the APAAP or PAP immunodetection systems (the latter with microwave pretreatment) is recommended for any immunohistochemical or non-isotopic in situ hybridisation investigation undertaken on gestational endometria.

Biotin↗
PubMed1997

Human papillomavirus and schistosomiasis associated bladder cancer.

AIMS: To determine the human papillomavirus DNA status of schistosomal associated squamous cell carcinoma of the urinary bladder in South Africa. METHODS: Twenty five archival samples of bladder squamous cell carcinoma associated with Schistosoma haematobium were subjected to non-isotopic in situ hybridisation and the polymerase chain reaction for the detection of human papillomavirus 6, 11, 16, 18, 31, and 33 genotypes. RESULTS: Using these two techniques, none of the 25 cases was shown to harbour human papillomavirus DNA. CONCLUSIONS: This study abrogates the role of human papillomavirus in schistosoma associated bladder carcinoma in South Africa. It is suggested that other factors including nitrosamine exposure, p53 mutation, and additional unknown chromosomal events play a major role in the development of this parasite associated neoplasm.

Carcinoma, Squamous Cell↗
PubMed1997

Myxoma in the carotid artery. Myxomatous occlusion of internal carotid artery.

BACKGROUND: We describe a patient with an unusual cause of internal carotid artery occlusion resulting in a stroke. CASE DESCRIPTION: A 41-year-old woman presented with a typical acute right middle cerebral artery territory infarct. Her hematological and cardiological status was assessed, including all extracranial vessels. Carotid angiography and a biopsy were performed of the occluded right internal carotid artery and demonstrated a myxoma. Cardiac investigations to determine the source of the myxoma, including transthoracic and transesophageal echocardiograms, CT and yo-yo CT scans, and MRI of the heart, were normal. No residual tumor or potential source of the tumor was found. CONCLUSION: The cause of stroke was a myxomatous occlusion of the right internal carotid artery. An entire cardiac tumor may have embolized with no detectable residual tumor in the heart; alternatively, a myxoma may have originated as a primary tumor in the carotid artery. To our knowledge, no primary myxoma has been reported to have originated in a blood vessel.

Adult↗