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Biomedical subjects

S Isaacs

Publications and source records attributed to S Isaacs.

At least 37 records · Page 2Linked to original sources
PubMed1998

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↗
PubMed1998

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↗
PubMed1998

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↗
PubMed1997

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↗
PubMed1997

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↗
PubMed1996

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↗
PubMed1995

Recognizing nursing informatics.

In our climate of economic uncertainty, readily accessible and reliable information is essential for cost effective decision making and forward planning in an efficient and effective manner. Information systems are widely used in the business industries to achieve the above. The state hospitals in South Africa have also realized the need for functional information systems. Where does this leave the division of nursing? This division usually comprises at least one third of the hospital establishment with very specific and often complex needs. The nurse managers at all levels have to plan, predict, forecast, monitor, and control in a similar manner to the business industries. What makes their decisions more critical is that they are dealing with human lives. A nursing informatics section with specially trained nurses will have to become an integral part of nursing, to enable nursing to keep abreast of the increasing demand for accurate and timely information for effective decision making. This paper will evaluate the importance of recognizing the need for an informatics section to evolve within the division of nursing, rather than within the general department of medical informatics.

Attitude to Computers↗
PubMed1994

Lung tumor induction in A/J mice by the tobacco smoke carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene: a potentially useful model for evaluation of chemopreventive agents.

The purpose of this study was to establish a lung tumor model for the evaluation of chemopreventive agents against lung cancer in smokers. Lung tumor induction in A/J mice by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (BaP) was studied using protocols in which these two tobacco smoke carcinogens were given individually or in combination. Groups of female A/J mice were treated by either intragastric gavage (i.g.) or by intraperitoneal injection (i.p.) with various doses of NNK and/or BaP for 8 consecutive weeks. The mice were killed either 9 or 19 weeks later and tumors of the lung and forestomach were counted. The i.g. route of administration proved to be more satisfactory than i.p. administration, because it avoided complications due to tumor formation at the injection site and associated mortality. A dose-response relationship for lung tumor induction by i.g. administration of NNK and BaP in combination was established in the mice killed 9 or 19 weeks after completion of carcinogen treatment. The highest total doses of NNK and BaP (a total of 24 mumol of each) induced more lung tumors than would have been expected by extrapolation from the lower doses. Comparisons of NNK and BaP given individually showed that BaP was more tumorigenic to the lung than NNK when given by the i.g. route; i.p. administrations of BaP were complicated by local tumor formation and mortality. The most favorable dosing regimen of NNK and BaP for evaluation of chemopreventive agents appears to be a total dose of 24 mumol of each, administered in eight weekly subdoses i.g., with sacrifice 9 weeks after completion of dosing. This regimen induced 10.5 +/- 4.4 lung adenomas/mouse. A combination of benzyl isothiocyanate and phenethyl isothiocyanate, given 2 h prior to each gavage of NNK and BaP, was found to be an effective inhibitor of lung tumor formation, reducing the tumor multiplicity to 5.9 +/- 5.7 lung adenomas/mouse (P < 0.001) and completely inhibiting forestomach tumor development. The results of this study provide a convenient model for assessing the efficacy of chemopreventive agents against lung cancer induction by tobacco smoke carcinogens.

Adenoma↗
PubMed1994

Referrals for inadequate progress of labour from the midwife obstetric units to the referral hospitals in Cape Town.

Referrals for inadequate progress of labour from the Midwife Obstetric Units (MOUs) to the referral hospitals are responsible for a significant part (approximately 5%) of the workload of these institutions in the Peninsula Maternal and Neonatal Service Region in Cape Town. It is essential for the maintenance of community credibility in the MOUs that patients who develop complications are timely and speedily transferred to the appropriate referral hospital. A sample of 251 patients, who were transferred from the MOUs to the referral hospitals for inadequate progress of labour in the first half of 1992, was analysed. The study showed that midwives in the MOUs had largely adhered to the Departmental referral criteria for that potentially serious complication of labour and had kept excellent records. The referrals, in terms of eventual outcome for the patients and their infants, had been largely appropriate. Several areas of concern were identified. These included incomplete assessment of the stage of labour on admission and inadequate monitoring of the fetal heart in a number of patients. Provision of analgesia in labour was generally inadequate. Ambulance delay was disturbingly common. Recommendations for measures to redress these management deficiencies are presented.

Female↗
PubMed1993

Photochemical inactivation of cell-associated human immunodeficiency virus in platelet concentrates.

Photochemical decontamination (PCD) of platelet concentrates, with adequate preservation of platelet function, has been shown using 8-methoxypsoralen (8-MOP) and long wavelength UV light (UVA). To further evaluate this technique, models for the inactivation of pathogenic human cell-associated viruses and integrated proviral sequences are required. We have assessed the ability of the PCD technique to inactivate cell-associated human immunodeficiency virus 1 (HIV-1) in platelet concentrates. We correlated PCD inhibition of HIV-1 infectivity with 8-MOP-DNA adduct formation in contaminating nucleated cells, and measured the inhibition of polymerase chain reaction (PCR)-mediated amplification of cellular DNA sequences as a surrogate for inactivation of integrated proviral nucleic acid sequences. After PCD treatment (8-MOP 300 micrograms/mL, UVA 17 mW/cm2) for 60 minutes, 0.5 x 10(6) plaque-forming units (PFU)/mL of cell-associated HIV-1 were inactivated and no virus was detectable by infectivity assay. After 60 minutes of PCD, 15 8-MOP-DNA adducts per 1,000 bp were formed, while in the absence of UVA, no adducts were formed. PCR-mediated amplification of a 242-bp cellular DNA sequence (HLA-DQ-alpha) was inhibited when greater than eight psoralen-DNA adducts per 1,000 bp were present. These studies indicate that high titers of cell-associated HIV-1 in platelet concentrates were inactivated by PCD, and the numbers of 8-MOP-DNA adducts in nucleated cells were sufficient to inhibit amplification of DNA segments that encode for as few as 80 amino acids. Based on the frequency of 8-MOP-DNA adducts, for the 10-kb HIV-1 genome, the probability of an integrated genome without at least one 8-MOP adduct after 60 minutes of PCD was 10(-33).

Blood Component Transfusion↗
PubMed1993

Electrical stunning of red deer (Cervus elaphus).

Eighteen of 23 red deer (Cervus elaphus) at a deer slaughtering premises were successfully stunned with an apparatus modified from that normally used to stun sheep. The five unsuccessful electrical stuns were associated with poor head restraint and poor head contact by the electrodes. The median stunning current was 0.9 A, and in the majority of cases the duration of stunning was less than 1 second. The signs of the electrically induced epileptiform seizures in the deer were dissimilar to those seen in sheep, cattle and pigs, in that the initial tonic phase was less marked, and of shorter duration. A similar shorter and less obvious tonic phase was noted in four deer shot with a captive bolt pistol. Two animals which were electrically stunned, and bled within 10 seconds, showed no signs of recovery while bleeding. The electroencephalograms of four deer stunned with currents of 1.3 A for a duration of either 0.5 or 1.0 seconds were recorded under more controlled conditions. All four animals developed electroencephalograms typical of an epileptiform seizure. The animals exhibited behavioural reactions similar to the other 18 animals in the trial at the deer slaughtering premises and were rendered unconscious for between 54 and 122 seconds. The electroencephalogram activity amplitude was greater than that recorded immediately before stunning and took between 6 and 9 seconds to build up to maximum value. It is concluded that, providing the heads of deer are adequately restrained, head-only electrical stunning can be incorporated into a humane method of slaughter for deer.

Journal Article↗
PubMed1993

Risk factors for uveitis in sarcoidosis.

Uveitis is a potentially sight-threatening complication of sarcoidosis. The object of this study was to determine which patients with sarcoidosis are at greater risk of developing uveitis. We retrospectively assessed 136 patients with clinical, radiological and histological features of sarcoidosis. Of the 48 patients (35.3%) with signs of intra-ocular inflammation, 28 had anterior uveitis, 2 had posterior uveitis and 18 had signs of panuveitis. When patients with uveitis were compared with patients without ophthalmic involvement, no significant demographic, clinical or laboratory differences were found. On linear discriminant analysis, however, the presence of ocular inflammation could be predicted in 32 out of 48 patients (66.6%); age at diagnosis and an elevated serum calcium level were relative risk factors. Awareness of the high incidence of uveitis and education of those at greater risk may result in earlier diagnosis and treatment of ocular inflammation.

Adolescent↗