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Biomedical subjects

H Clarke

Publications and source records attributed to H Clarke.

At least 37 records · Page 2Linked to original sources
PubMed1999

Breast health practices and South Asian women.

Breast cancer is an important women's health issue in all communities. To detect breast cancer early, all women should practise monthly breast self-examination, have regular clinical breast examinations and attend mammography screening at suggested intervals. Participation in these breast health practices is influenced by a wide variety of factors, including how women define health and health practices, priorities in women's lives and their explanations of the causes of diseases such as cancer.

Adult↗
PubMed1998

Beliefs related to breast health practices: the perceptions of South Asian women living in Canada.

Breast cancer is becoming a major concern for many South Asian women. Clinical observations of women from a South Asian community living in Canada revealed an under use of early detection strategies. The purpose of this qualitative ethnoscience study was to examine breast health practices from the perspective of South Asian women to provide a foundation for the development of culturally suitable breast health services for this group. Open-ended interviews were conducted with a convenience sample of 50 South Asian women over the age of 30 who had not been diagnosed with breast cancer. Adequate representation of the main religious groups (i.e. Sikh, Hindu, Muslim and Christian) was ensured through sampling techniques. Analysis of translated interviews involved identification of themes and the development of a taxonomy to represent relationships among emerging cultural themes and domains. Four central domains of beliefs related to breast health practices were identified: beliefs about a woman's calling, beliefs about cancer, beliefs about taking care of your breasts and beliefs about accessing services. These beliefs hold important implications for how health promotion strategies should be structured and offered, In particular, attention must be paid to the language that is used to talk about breast cancer, the importance of the role of the family in women's health decisions and traditions related to using narratives to share information and advice.

Adult↗
PubMed1998

Clinical relapses and disease activity on magnetic resonance imaging associated with viral upper respiratory tract infections in multiple sclerosis.

BACKGROUND: Although the risk of clinical attacks of multiple sclerosis seems to be significantly increased with viral upper respiratory tract infections (URTI), serological evidence for the reported association remains controversial. In addition, although MRI is six to 10 times more sensitive than clinical exacerbations in indexing disease activity, any possible association between URTI and MRI activity has yet to be investigated. OBJECTIVES: To examine the relation between URTI and disease activity, in multiple sclerosis patients participating in a placebo controlled trial of interferon beta-1a, as indexed both by clinical exacerbation rate and by the number and volume of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) enhancing lesions on MRI. "At risk" periods were defined around symptomatic URTI, with or without serological confirmation. RESULTS: The relative risk of clinical relapse for serologically unconfirmed symptomatic URTI was 2.1 (p=0.004). Raised antiviral antibody titres conferred a relative risk of multiple sclerosis exacerbations that was 3.4 times higher than the "not at risk" periods (annual attack rates of 5.7 v 1.6, respectively, p=0.006). There was no definite relation between the number or the volume of active lesions on MRI and either symptomatic or serologically defined at risk periods. CONCLUSIONS: These results confirm the previously reported association between viral infections and multiple sclerosis exacerbations and indicate that the relative risk may be even higher when viral infection is serologically confirmed. However, the results, perhaps because of the confounding effects of interferon beta-1a, do not provide convincing evidence of increased blood-brain barrier breakdown or inflammation during periods of virally induced immune stimulation.

Adult↗
PubMed1998

Protein synthesis and secretion by the epididymis of the brushtail possum, Trichosurus vulpecula.

In this study of brushtail possums, proteins present in epididymal fluid and not present in blood plasma and those that become associated with spermatozoa as they pass along the tract were investigated. At least 19 proteins were present in epididymal fluid in the various regions of the tract that were not detected in serum. Some of these may be present on the sperm plasmalemma. Six proteins were extracted from caput spermatozoa (M(r) 117,000, 103,000, 87,500, 85,000, 62,000 and 33,000) that did not appear in the caudal sperm extracts. Eight proteins (M(r) 50,000, 49,000, 32,000, 27,000, 26,500, 25,000, 24,500 and 18,000) were localized to caudal sperm extracts. These findings suggest that some sperm proteins are lost or modified, whereas others are added to the sperm plasma membrane during epididymal transit. In vitro incorporation of [35S]methionine by the epididymal tissue showed that the distal caput and corpus are the most active regions in the synthesis and secretion of proteins. Four caudal epididymal proteins (M(r) 72,000, 31,000, 26,500 and 21,000) were partially sequenced. Those of M(r) 31,000 and 26,500 had the same N-terminal amino acid sequence suggesting post-translational modification of the same protein; they showed homology to a retinoic acid-binding protein. The protein of M(r) 72,000 was found to be homologous to alpha-fetoprotein, whereas the protein of M(r) 21,000 showed no significant homology to any protein in the database. These results show that the lumen of the epididymis has many proteins that are not present in the blood, some of which appear to become associated with spermatozoa during epididymal transit.

Amino Acid Sequence↗
PubMed1997

The Stanmore total hip arthroplasty. A 15- to 20-year follow-up study.

An ongoing study was made of 804 primary Stanmore total hip prostheses implanted in 839 patients between 1973 and 1991. The earliest surviving implants were brought back for radiologic and clinical review in 1995 at an average of 17 years after surgery. The remainder of the patients still living were sent a questionnaire to assess their current status. Survivorship was 95% at 10 years, 85% at 15 years, and 73% at 20 years. The average Merle d'Aubigné-Postel score was excellent up until 14 years. Patient satisfaction remained high until 22 years. Overall, 10% of the prostheses had failed. The results of this study suggest that the Stanmore prosthesis is capable of producing satisfactory long-term results that compare favorably with those of other cemented prostheses.

Adolescent↗
PubMed1997

Selection of antigens for use in a virus-vectored immunocontraceptive vaccine: PH-20 as a case study.

The European wild rabbit (Oryctolagus cuniculus) has become the major agricultural and environmental pest species in Australia. Current methods of rabbit control are lethal procedures which are increasingly questioned for their overall efficiency, applicability, specificity, cost and humaneness. New initiatives are required. One such initiative is virus-vectored immunocontraception. In this approach, the lagomorph-specific myxoma virus will be genetically engineered to include genes encoding components of rabbit gametes which can induce an immune response that causes infertility. Central to such a strategy is the ability to identify antigens capable of inducing an immunocontraceptive response. A strategy for identifying such antigens has been described previously. A case study of one sperm antigen, PH-20, is reported here. The issues involved in developing this antigen to the stage where it could be considered as a candidate for insertion into a recombinant myxoma virus with the ultimate goal of testing for immunocontraceptive efficacy are discussed. Techniques for inserting genes into myxoma virus have been described previously. The knowledge gained from research with this particular antigen are broadly applicable to other antigens used for both immunocontraceptive vaccines in general and, specifically, for virus-vectored immunocontraception.

Animals↗
PubMed1997

Quantitative visualization of flow through a centrifugal blood pump: effect of washout holes.

To clarify the effect of washout holes on the flow in a centrifugal blood pump to prevent blood stagnation, a quantitative flow visualization technique was applied to compare flows in models with and without washout holes. A scaled-up model of a prototype pump and a high speed video camera were used for the flow visualization, and images were processed by particle tracking velocimetry. Particular attention was paid to the flow through the gaps behind and in front of the impeller. The results showed that in the gap behind the impeller, washout holes caused not only an inward flow, but also an increase in the tangential velocities. In the gap in front of the impeller, washout holes caused an outward flow and a decrease in the tangential velocities. Head flow characteristics were little affected by the washout holes in this initial design for which the flow through the washout holes was set to be approximately 10% of the flow in the external circuit. These results suggest that the flow through washout holes is significant in the prevention of blood stagnation in 2 ways. First, the inward radial velocity behind the impeller and outward velocity in front of the impeller result in fluid exchange, and second, a tangential velocity increase reduces fluid stagnation behind the impeller.

Blood Flow Velocity↗
PubMed1997

Alpha-glutathione s-transferase (alpha-GST) release, an early indicator of carbon tetrachloride hepatotoxicity in the rat.

1. The use of the cytoplasmic enzyme, alpha glutathione s-transferase (alpha-GST) as an early index of carbon tetrachloride (CCl4) toxicity in the rat was investigated and compared with a standard enzyme, marker, aspartate aminotransferase (AST). The hepatotoxic effects of CCl4 in the rat were determined in a time and dose-response study. 2. Following CCl4 exposure, alpha-GST release was shown to be an earlier and more sensitive biomarker of hepatotoxicity than AST. 3. Significant increases in alpha-GST were detected 2 h after CCl4 exposure. Using the enzyme marker AST, this early hepatotoxic injury went undetected. At 6 and 16 h, alpha-GST was also a more sensitive indicator of hepatotoxicity than AST. 4. alpha-GST release was significantly increased at a dose of 5 microliters/kg, the lowest concentration of CCl4 administered and clearly responded in a dose-dependent manner with increasing doses of CCl4. In contrast, release of AST did not reach statistical significance until a dose of 25 microliters/kg. 5. Thus, these findings indicate that alpha-GST is a more sensitive and more accurate reflector of CCl4 induced hepatotoxicity than AST.

Administration, Oral↗
PubMed1996

Trial of isotretinoin and calcitriol monitored by CA 125 in patients with ovarian cancer.

Twenty-two asymptomatic women with rising CA 125 levels after chemotherapy for ovarian cancer were entered into a trial of isotretinoin combined with calcitriol. Tumours were evaluated according to precise criteria based on serial CA 125 levels and by comparing regression slopes of CA 125 before and during therapy. There was no evidence based on CA 125 of any responses or significant change in tumour growth rate.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Forward planning and stability of the Australian migration program.

"Should the Australian immigration intake be forward-planned and, if so, should the resulting intake be numerically stable through time? There are sound reasons for anticipating the effects of current intakes on future intakes and for basing current intakes on Australia's long-term national objectives. These policy requirements imply a case for forward planning but not the need for a stable intake. Appropriately designed numerically unstable intakes are preferable to stable intakes because instability, while introducing adjustment costs, avoids more significant losses due to reduced selectivity in the entry mix."

Australia↗
PubMed1996

United Kingdom labour emigration and capital exports 1816-1991.

"This paper is concerned primarily with examining the nature of linkages between capital and labour emigration from the U.K. We also consider whether the primary impulses for emigration were push or pull influences--the main intent is to look at the relation between the flows rather than the determinants of either. The nature of the capital-labour link is examined qualitatively using historical argument and quantitatively using statistical tests and causality analysis. The starting time for analysis is the end of the Napoleonic Wars when useful data became available." (SUMMARY IN FRE AND SPA)

Demography↗
PubMed1995

Cerebellar hypoplasia in the second trimester associated with microcephaly at birth.

The antenatal diagnosis of microcephaly is most commonly made in the third trimester. Biometric measurements of the head of three or four standard deviations below the mean are suggestive of microcephaly. We report a case of microcephaly where abnormalities in intracerebral architecture, i.e. cerebellar hypoplasia, were noted early in the second trimester.

Adult↗
PubMed1995

Factors affecting the absolute bioavailability of nifedipine.

1. Nifedipine was administered to eight volunteers (seven Caucasian, one East Asian of Chinese origin) as a single 10 mg capsule orally and as 2.5 mg intravenously. The pharmacokinetics were determined under fasting conditions and following 200 ml double strength grapefruit juice taken orally both 2 h before and at the time of dosing. 2. In a separate study, the pharmacokinetics of nifedipine were defined in eight South Asian volunteers (with both parents originating from the Indian subcontinent) following 10 mg nifedipine orally and 2.5 mg intravenously. 3. The administration of grapefruit juice did not alter the pharmacokinetics of intravenous nifedipine, but resulted in a significantly increased area under the plasma concentration-time curve (AUC) (191 +/- 59 c.f. 301 +/- 95 ng ml-1 h, P < 0.05) and bioavailability (0.63 +/- 0.18 c.f. 0.86 +/- 0.15, P < 0.05) following oral nifedipine. The elimination half-life was unchanged by administration of grapefruit juice and there was no evidence of decreased formation of the nitropyridine first-pass metabolite. 4. The AUC of nifedipine after intravenous administration was significantly higher in South Asian subjects than in Caucasians (146 +/- 39 c.f. 74 +/- 18 ng ml-1 h, P < 0.002). This was due to a lower systemic clearance in the South Asians which was 50% of that in the Caucasians. The half-life was markedly prolonged in South Asians (4.1 +/- 1.9 c.f. 1.7 +/- 0.5 h, P < 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1994

Cerebrospinal fluid shunt infection due to Corynebacterium xerosis.

We report the case of a neonate who developed ventriculitis following insertion of a ventriculoperitoneal shunt. Corynebacterium xerosis was isolated from CSF and from the tip of the catheter after it was removed. The isolate was resistant to multiple antibiotics, but the infant responded to treatment with vancomycin.

Ciprofloxacin↗
PubMed1993

The relation of venous ulceration with ambulatory venous pressure measurements.

Two hundred thirty-six limbs of 220 unselected patients who were admitted with venous problems (83 with ulcers) were studied with continuous-wave Doppler ultrasonography, duplex scanning, and ambulatory venous pressure measurements. Patients with evidence of deep venous disease because of reflux or obstruction in the deep veins on Doppler and duplex ultrasonic examination or with an ambulatory venous pressure greater than 45 mm Hg despite the ankle cuff had venography. One hundred fifty-three limbs had superficial venous disease (reflux in the superficial veins with competent popliteal valves), and 83 limbs had deep venous disease (popliteal reflux on duplex examination or deep venous obstruction on venography). No ulceration occurred in limbs with ambulatory venous pressure < 30 mm Hg, and there was a 100% incidence with ambulatory venous pressure > 90 mm Hg. A linear increase occurred from 14% in limbs with ambulatory venous pressure between 31 and 40 mm Hg to 100% in limbs with ambulatory venous pressure greater than 90 mm Hg (r = 0.79). In the groups studied, an increased incidence of ulceration was associated with an increase in ambulatory venous pressure irrespective of whether the venous problem was the result of superficial or deep venous disease. Ambulatory venous pressure has both diagnostic and prognostic significance in patients with venous disease.

Blood Flow Velocity↗