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Biomedical subjects

S Isaacs

Publications and source records attributed to S Isaacs.

At least 19 recordsLinked to original sources

Illness outbreak associated with Escherichia coli O157:H7 in Genoa salami. E. coli O157:H7 Working Group.

BACKGROUND: An outbreak of Escherichia coli O157:H7 infection was identified in the spring of 1998, with a 7-fold increase in the number of laboratory-confirmed E. coli O157:H7 cases in southern Ontario. This prompted an intensive investigation by local, provincial and federal public health officials. METHODS: Case interviews of 25 people from southern Ontario were conducted using a broad food history and environmental exposure survey. Laboratory investigations involved both case and food sampling. Specimens of foods sold locally and reportedly consumed by those affected were tested. Common suppliers of suspected foods were identified by cross-referencing suppliers' lists with stores frequented by those who fell ill. A case-control study involving 25 cases and 49 age-matched controls was conducted. This was followed by a comprehensive environmental investigation of the meat processing plant identified as the source of the E. coli. RESULTS: Thirty-nine outbreak-related cases occurred between April 3 and June 2, 1998. Of the 36 case specimens tested all were positive for E. coli O157:H7. The case-control study identified Genoa salami as the most probable (odds ratio 8 [confidence interval 2-35]) source of the outbreak. Samples of Genoa salami produced by the most commonly identified supplier later tested positive for E. coli O157:H7, and the pathogen matched the same pulsed-field gel electrophoresis pattern and phage type of the case specimens. INTERPRETATION: Our investigation, which led to a national recall of the brand of dry fermented Genoa salami identified as the source of the outbreak, supports an adherence to stringent manufacturing requirements for fermented meat products. A review of the Canadian standards for fermented meat processing and the effectiveness of their implementation is warranted.

Adolescent↗

Expression of p53 and p21waf1/cip1 in gastric carcinoma: lack of inter-relationship or correlation with prognosis.

AIMS: The cell cycle regulators p53 and p21waf1/cip1 are expressed variably in human cancers. We investigated their expression in gastric carcinoma and determined their inter-relationship and prognostic significance. METHODS: Immunohistochemistry was used to determine their expression in material from 100 resected specimens of gastric carcinoma, and comparison was then made of the degree of expression between each, with conventional clinicopathological indices and with survival. RESULTS: Positivity was found with p53 (40%) and p21 (75%). There was no significant correlation between the expression of each individual marker, nor between each marker and 5-year survival. There appeared to be an association between p53 expression and lymph node metastases, and a higher frequency of p21waf1/cip1 expression in males. CONCLUSIONS: The expression of p53 and p21waf1/cip1 as detected by immunohistochemistry were of no value in predicting the prognosis of patients with gastric carcinoma.

Biomarkers, Tumor↗

Tonsillectomy and tonsillitis in Cape Town--age and sex of patients.

OBJECTIVES: To assess the sex and age of patients undergoing tonsillectomy in the Cape Town metropolitan area. METHODOLOGY: A retrospective audit was conducted from 1991 to 1995 comparing the sex and age of patients undergoing tonsillectomy with patients admitted to hospital for acute tonsillitis and the general population. RESULTS: A total of 7,250 tonsillectomies were performed for recurrent tonsillitis, and 111 adult patients were admitted with acute tonsillitis. When the data for the adult tonsillectomy patients were isolated, the female/male ratio was 3.22:1, which is highly significant when compared with the data for the general population (Cornfield's 95% confidence limit: 2.82, 3.68) and for patients with acute tonsillitis (Cornfield's 95% confidence limit: 1.14, 2.65). CONCLUSION: Recurrent tonsillitis requiring tonsillectomy occurs more commonly in female than male patients.

Adolescent↗

Parathyroid and thyroid function five years after treatment of laryngeal and hypopharyngeal carcinoma.

The proximity of the thyroid and parathyroid glands to the larynx and hypopharynx puts them at risk from treatment of squamous cell carcinoma (SCC) of this region. Consequently parathyroid and thyroid function was evaluated in patients surviving at least 5 years following treatment of primary SCC of the larynx or hypopharynx. Twenty-eight patients, initially treated from 1990 to 1992, were assessed and divided into four groups according to treatment received. Hypoparathyroidism (partial and hypocalcaemic) occurred in 88% and hypothyroidism (clinical and subclinical) in 50% in Group 1 (radiotherapy only) Group 2 (salvage laryngectomy for failed radiotherapy) had 66% hypoparathyroid and 33% hypothyroid. Group 3 (surgery + radiotherapy combined) had 89% hypoparathyroid and 89% hypothyroid. Group 4 (surgery only) had 63% hypoparathyroid and 63% hypothyroid. Significant endocrine hypofunction therefore occurs following the treatment of laryngopharyngeal carcinoma, more so with radiotherapy and combined therapy than with surgery alone.

Carcinoma, Squamous Cell↗

Ethnicity and patterns of spondyloarthritis in South Africa--analysis of 100 patients.

OBJECTIVE: To determine the spectrum and ethnic differences of spondyloarthritis disease patterns in patients attending the Rheumatic Diseases Unit, University of Cape Town, South Africa. METHODS: A retrospective survey of case records of 100 patients with spondyloarthritis seen between January 1988 and January 1995. RESULTS: Of these 100 patients, 71 were male, 53 were Colored [mixed race descendants of Khoisan (Hottentot and Bushmen), Whites, Malays and Black Africans], 40 White, 5 Black and 2 Indian (descendants of immigrants from the Indian subcontinent). Our results show that the prevalence and disease patterns of spondyloarthritis in this South African cohort are comparable to those seen in Europe and North America with respect to clinical and radiological features, as well as therapeutic and orthopedic surgical requirements. No major ethnic differences in disease patterns were observed in White and Colored patients studied. CONCLUSION: The spectrum of spondyloarthritis in South Africa is similar to that seen elsewhere in the world. Our study confirmed the rarity of these conditions in Black South Africans.

Age of Onset↗

Hypoparathyroidism after the treatment of laryngopharyngeal carcinoma.

Thirty patients with squamous cell carcinoma of the laryngopharynx were treated with surgery (total laryngectomy and hemithyroidectomy) and radiotherapy. Group 1 (n = 7) patients had surgery only; Group 2 (n = 7) had radiotherapy followed by salvage surgery while Group 3 (n = 16) had surgery followed by radiotherapy. Parathyroid hormone and calcium levels were measured pre- and post-operatively and post-radiotherapy. In Group 1 no patients were hypoparathyroid. In Group 2, 29 per cent of patients preoperatively and 57 per cent post-operatively, were hypoparathyroid. In Group 3, no patients were hypoparathyroid pre-operatively, while 25 per cent were hypoparathyroid post-operatively and post-radiotherapy. Parathyroid hormone and calcium levels were averaged and compared within and between each group. There was no significant difference within each group, when comparing levels post-operatively and post-radiotherapy from those of pre-operatively. There was no significant difference in levels between each of Groups 1, 2 or 3 (p > 0.05).

Aged↗

Evidence for a prostate cancer susceptibility locus on the X chromosome.

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Adult↗

Suicide in the Northwest Territories: A descriptive review.

The incidence of suicide among the populations of the Northwest Territories (NWT) is notably higher than in the rest of Canada. A comparison of three five-year time periods between 1982 and 1996 reveals an increasing incidence rate, particularly for Nunavat, the eastern half of the NWT, occupied primarily by Inuit people. This is largely attributable to a rising use of hanging as opposed to other methods of suicide. A coroner's record review of suicides occurring between 1994 and 1996 demonstrates the preponderance of young males and of Inuit among those who committed suicide, the majority of whom committed suicide in familiar settings, usually their own homes, and often while others were on the premises. Thirty-six percent of those who committed suicide had experienced a recent family or relationship breakup, and twenty-one percent were facing criminal proceedings. Understanding the impact of these and other reported circumstances on the imminent risk of suicide requires further investigation.

Adolescent↗

User attitudes to a heritage hospital information system.

A heritage system is one that has exceeded its lifespan but continues to be used for various reasons, despite the problems it may be causing. Groote Schuur Hospital has a Hospital Information System that is more than 25 years old. The present study reports the result of a survey on users' attitude and sense of involvement in this system. An attempt is made to determine whether users feel the need for change and whether a sense of involvement is related to this need.

Attitude to Computers↗

High prevalence of GBV-C hepatitis G virus infection in a rural South African population.

A novel virus, GBV-C/hepatitis G virus (GBV-C/HGV), has been cloned and characterised recently. GBV-C/HGV global epidemiology and risk factors for acquisition are currently unclear. We aimed to establish the determinants of this infection in a rural South African (SA) population. The study population included two samples, namely a community-based sample, and consenting persons from a nonspecialist outpatient department in the same district. A questionnaire regarding demographic details and putative risk factors was administered; blood samples were taken on which a polymerase chain reaction (PCR) was performed for both 5'NCR and NS5a regions of GBV-C/HGV using commercially available primers and probes. Two hundred and forty-nine people were studied with a mean GBV-C/HGV prevalence of 10.4%. Outpatient department and community prevalences differed significantly (18.0% and 6.3%, respectively, P = 0.004). GBV-C/HGV infection was associated with excessive alcohol consumption (P = 0.02; OR, 4.18) and a lack of waterborne sewerage (P = 0.04). PCR amplification of the NS5a region of all but two South African GBV-C/HGV positive samples showed poor reactivity. The prevalence of GBV-C/HGV in rural SA appears to be higher than that reported from Europe and North America. Infection appeared to be associated with excess alcohol intake and a history of previous blood transfusion. The discrepant NS5a and 5'NCR PCR sensitivity in this study raises the possibility of genetic differences in southern African GBV-C/HGV.

Adolescent↗

Hepatitis E in South Africa: evidence for sporadic spread and increased seroprevalence in rural areas.

Hepatitis E virus (HEV) is a major cause of non-A, non-B hepatitis in developing countries. Factors influencing sporadic spread of hepatitis E are unclear. We examined anti-HEV seroprevalence and demographic data from 407 urban and 360 rural black South African adults living in formal housing, squatter camps, or mud huts. Anti-HEV sero-prevalence ranged from 5.8% to 19.1% (mean 10.7%) in the different regions. Mean urban and rural rates were 6.6% and 15.3%, respectively (P = 0.0001). Rural mud hut dwellers, using unchlorinated river water, were at greater risk (17.4%) than rural villagers (5.3%; P = 0.008). A linear relation was found between seroprevalence and age, suggesting sporadic spread. The high prevalence in mud hut dwellers suggests that contaminated water plays a major role in HEV spread in South Africa. Routine chlorination or boiling of river drinking water before consumption may reduce HEV infection.

Adult↗