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Biomedical subjects

K Robinson

Publications and source records attributed to K Robinson.

At least 73 records · Page 4Linked to original sources
PubMed1999

The role of patients in the implementation of the National Kidney Foundation-Dialysis Outcomes Quality Initiative.

Patients have a fundamental right to be involved in making decisions that affect their health care treatment and outcomes. Patients need to be knowledgeable about disease process and treatment options to exercise this right. The National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) Clinical Practice Guidelines on Hemodialysis Adequacy, Peritoneal Dialysis Adequacy, Treatment of Anemia of Chronic Renal Failure, and Vascular Access, introduced in 1997, include new clinical recommendations that may impact patient treatment choices. Access to these guidelines presents a unique professional opportunity to empower patients through education related to NKF-DOQI. This article highlights the role of patients in implementing NKF-DOQI in light of studies conducted by two renal patient organizations, the National Kidney Foundation (NKF) and the American Association of Kidney Patients (AAKP). Results from the AAKP survey indicate that end-stage renal disease patients are willing to change behavior to feel better and live longer. Results from the NKF focus study show that dialysis patients need to receive information about NKF-DOQI and understand its direct impact on patient outcomes. In addition, results from both studies reveal that patients feel strongly about participating in health care decisions that impact on their treatment and outcomes.

Association↗
PubMed1999

Prevalence and determinants of hyperhomocysteinemia in hemodialysis and peritoneal dialysis.

BACKGROUND: Hyperhomocysteinemia is an independent risk factor for atherosclerotic complications in patients with end-stage renal disease, although the mechanisms remain unclear. The major determinants of plasma homocysteine concentration are usually folate, vitamin B12, pyridoxal 5'-phosphate (vitamin B6), and glomerular filtration rate. METHODS: We measured factors, including plasma folate, vitamin B12, vitamin B6, creatinine, as well as the dose and duration of dialysis, that might affect plasma homocysteine concentrations in 130 patients on hemodialysis (HD) and compared these observations with those in 46 patients on peritoneal dialysis (PD). Independent determinants of total homocysteine were identified using a multiple logistical regression analysis. RESULTS: Total homocysteine values averaged 29.8 mumol/liter in HD patients, significantly higher than the mean value of 19.9 mumol/liter observed in patients on PD (P < 0.001). The prevalence of hyperhomocysteinemia was 90.8% among HD patients, significantly higher than the prevalence of 67.4% among PD patients. Folate values in HD patients averaged 45.5 nmol/liter and were significantly lower than in PD patients (104.2 nmol/liter, P < 0.001). For patients on HD, the only determinant of total homocysteine concentration was plasma folate (r = -0.31, P < 0.001). In contrast, for PD patients, total homocysteine did not correlate with plasma folate, vitamin B12, or vitamin B6. CONCLUSIONS: Hyperhomocysteinemia is more prevalent and intense in HD patients compared with those on PD. The homocysteine response may become refractory to excess folate supplementation in PD patients.

Creatinine↗
PubMed1999

Homocysteine, vitamin status and risk of vascular disease; effects of gender and menopausal status. European COMAC Group.

BACKGROUND: Elevated plasma total homocysteine (tHcy) is a known risk factor for vascular disease. Gender, age, and circulating levels of folate, vitamins B(6)and B(12)affect tHcy levels. Objectives To study associations of gender and age with levels of plasma tHcy, and to examine the relationships of tHcy and circulating levels of folate, vitamins B(6)and B(12)with risk of vascular disease in men and women (pre- and post-menopausal). MATERIAL AND METHODS: In a multicentre case-control study in Europe, 750 patients (544 men, 206 women) with documented vascular disease of the coronary, cerebral, or peripheral vessels and 800 control subjects (570 men, 230 women) were enrolled. Plasma tHcy levels (fasting and after methionine loading) and circulating levels of the vitamins were measured. Adjustment for age and centre was carried out for all statistical analyses, with additional adjustment for serum creatinine and vitamins for the tHcy comparisons between the sexes and between cases and controls. Risk analyses included adjustment for creatinine and traditional risk factors. Relationships between age, gender and tHcy were studied among control subjects only. RESULTS: Fasting tHcy levels were lower in women than in men. Levels of tHcy showed a positive association with age, for both sexes. In the post-menopausal age category, female post-methionine load tHcy levels surpassed levels of men. Elevation of tHcy (defined as >80th percentile of controls) appeared to be at least as strong a risk factor for vascular disease in women as in men, even before the menopause. For post-methionine load tHcy, there was a 40% stronger association with vascular disease in women than in men. In both sexes, but especially in pre-menopausal women, low circulating levels of vitamin B(6)conferred a two- to threefold increased risk of vascular disease, independent of tHcy. In men, but not in women, low (defined as <20th percentile of controls) circulating folate levels were associated with a 50% increased risk of vascular disease. CONCLUSIONS: Elevation of tHcy appears to be at least as strong a risk for vascular disease in women as men, even before the menopause. Our data indicate that associations of the various tHcy measurements (and the vitamins that determine them), with risks of vascular disease may differ between the sexes. The tHcy-independent relationship of vitamin B(6)with vascular disease indicates that it will be advisable to test the effects of vitamin B(6)in clinical trials.

Case-Control Studies↗
PubMed1999

Quality of life outcomes following dacryocystorhinostomy: external and endonasal laser techniques compared.

AIMS/BACKGROUND. Endonasal laser dacryocystorhinostomy (ELDCR) has recently become established as an alternative technique to conventional external DCR (EXDCR) for relief of epiphora. The aim of this study was to compare quality of life and symptomatic outcomes in patients treated by these two methods. METHODS. A postal questionnaire was sent to 204 ELDCR and 78 EXDCR patients who had undergone surgery under our care more than 6 months previously. The questionnaire included the validated 18-item Glasgow Benefit Inventory (GBI) and 5 further questions addressing ocular symptomatology. RESULTS. Fully completed questionnaires were received from 156 ELDCR and 50 EXDCR patients. Mean GBI scores of +16.8 (ELDCR) and +23.2 (EXDCR) were obtained (Mann-Whitney U test = NS). Ocular symptom scores were +33 (ELDCR) and +54 (EXDCR) (p=0.005). CONCLUSION. Patients undergoing either ELDCR or EXDCR experience significant benefit in their healthcare status as detected by the GBI. There is no significant difference between the scores obtained by the two groups of patients. There were improvements in ocular symptom scores in both groups, with patients who had EXDCR scoring significantly better than the ELDCR group.

Journal Article↗
PubMed1999

A profile of the clients of male sex workers in three Australian cities.

OBJECTIVE: This paper describes the profile of clients as reported by 186 male sex workers in three Australian cities. METHOD: The data were collected using a diary which was completed after each commercial sexual encounter with a male client over a two-week period. The data reported in this study are based on reports from 2,088 sex encounters and a profile of 1,776 clients. RESULTS: The findings reveal, for example, that the most common source used for recruiting clients was advertisements, followed by escort agencies, although there were differences between the three cities; the majority of the clients were in their 40s but clients of street workers were younger; clients were most often classified as 'middle class', with differences by source of client recruitment; less than half the clients were identified as being gay and a significant number were identified as bisexual or straight; alcohol and drug use took place in a small percentage of the encounters; most workers had some information about their clients, such as occupation and home number; violence was infrequent; and unsafe sex was requested in a minority of the encounters. CONCLUSION: Overall, the results reveal that clients of male sex workers are a highly heterogeneous group. IMPLICATIONS: The paper highlights a number of issues which can further promote safety and public accountability in male sex work.

Adolescent↗
PubMed1999

Discriminant analysis of ribotype profiles of Escherichia coli for differentiating human and nonhuman sources of fecal pollution.

Estuarine waters receive fecal pollution from a variety of sources, including humans and wildlife. Escherichia coli is a ubiquitous bacterium in the intestines of warm-blooded animals and is used as an indicator of fecal pollution. However, its presence does not specifically differentiate sources of pollution. A total of 238 E. coli isolates from human sources (HS) and nonhuman sources (NHS) were collected from the Apalachicola National Estuarine Research Reserve, from associated sewage treatment plants, and directly from animals and tested for ribotype (RT) profile. HS and NHS isolates showed 41 and 61 RT profiles, respectively. At a similarity index of ca. 50%, HS and NHS isolates demonstrated four clusters, with the majority of HS and NHS isolates located in clusters C and D; isolates obtained directly from human and animal feces also could be grouped within these clusters. Discriminant analysis (DA) of RT profiles showed that 97% of the NHS isolates and 100% of the animal fecal isolates were correctly classified. The average rate of correct classification for HS and NHS isolates was 82%. We conclude that DA of RT profiles may be a useful method for identifying HS and NHS fecal pollution and may potentially facilitate management practices.

Animals↗
PubMed1999

Evidence-based medicine and its implications for audiological science.

Evidence-based medicine is the use of current best evidence in making decisions about individual patients. It involves formulating a question, searching for information, appraisal of the literature, implementation and subsequent audit. Two case studies involving a non-linear hearing aid and cochlear implantation are used to illustrate the process. Critical appraisal of the evidence-based medicine in the general literature shows little sign that the approach is effective and indicates that further rigorous evaluation is a priority. It is suggested that systematic reviews and clinical practice guidelines should be a high priority for audiologists and that a working group of audiologists should form to promote their production.

Adolescent↗
PubMed1999

Homocysteine: an emerging age-related cardiovascular risk factor.

Homocysteine is an intermediate formed during the metabolism of the essential sulfur containing amino acid methionine. Homocysteine concentration rises progressively with age in men and women, making it an important risk factor for cardiovascular disease. The causes are still under study, but likely culprits include clinical or subclinical folate and B vitamin deficiencies and possibly renal dysfunction. The association between adverse cardiovascular events and plasma homocysteine persists in older populations. In women, homocysteine levels increase after menopause and may be related to decreased estrogen concentrations. Folic acid supplementation decreases homocysteine concentration, but coadministration of vitamin B12 may be needed to prevent irreversible neurologic damage.

Age Factors↗
PubMed1999

Homocysteine and arterial occlusive disease: a concise review.

Many cross-sectional and prospective studies have shown that raised serum/plasma levels of total homocysteine increase the risk of coronary, cerebral, and peripheral artery disease. The risk associated with hyperhomocysteinemia appears to be concentration-dependent and not attributable to traditional risk factors. The odds ratio for ischemic heart disease has been estimated to be 1.4 for every 5 mumol/l increase of total plasma homocysteine. Median fasting total plasma homocysteine in adult males is approximately 10 mumol/l. Mild hyperhomocysteinemia is estimated to occur in 5-10% of the general population. Plasma concentrations are increased as a result of age, male gender, impaired renal function, low vitamin B intake, and genetically-determined defects of the enzymes involved in homocysteine metabolism. Folate supplements can reduce total homocysteine levels by approximately 25%. Studies in vitro and in vivo indicate that homocysteine can impair endothelial function. Despite increasing recognition of hyperhomocysteinemia as a risk factor for arterial occlusive disease, irrefutable proof that mild hyperhomocysteinemia contributes directly to the pathogenesis of atherothrombosis will come if interventions to lower total homocysteine reduce cardiovascular events. Family studies may also provide evidence of causality if genetic causes of hyperhomocysteinemia are found to segregate with disease.

Arterial Occlusive Diseases↗
PubMed1998

Implications of developmental plasticity for the language acquisition of deaf children with cochlear implants.

The study of language acquisition in profoundly deaf children with cochlear implants informs us about the developmental plasticity of the auditory system. Sensory activity leads to neural development, and the sustained effects of sensory inactivity can lead to a loss of responsiveness. These effects may be reversed by the subsequent provision of sensory stimulation, such as that delivered by cochlear implants. Behavioral and electrophysiological research on the effects of speech deprivation on language acquisition shows that the age and modality of language acquisition is an important determinant of adult linguistic performance. Studies on profoundly deaf children deprived of speech stimulation, and then provided with a cochlear implant giving them access to the speech frequencies, shows that congenitally deaf children implanted under the age of around 5 years are likely to perform better on speech perception and speech production tasks than children implanted at an older age. Further investigation is required to understand why these large individual differences exist. In addition, other key issues for research are the effects of compensatory visual and somatosensory development prior to implantation, whether there is a maturational delay that approximates to the period of speech deprivation prior to implantation, and whether there are a number of sensitive periods that together describe the cascade of processes that underlies language acquisition.

Adult↗
PubMed1998

High homocysteine, low folate, and low vitamin B6 concentrations: prevalent risk factors for vascular disease in heart transplant recipients.

BACKGROUND: A high plasma homocysteine concentration is a risk factor for atherosclerosis and thrombosis, which are major causes of morbidity and mortality in heart transplant patients. High homocysteine concentrations may be caused by lower folate and vitamin B6 levels. We hypothesized that these patients might have high homocysteine concentrations and low levels of folate and vitamin B6, which could contribute to the development of vascular complications. METHODS: Total fasting plasma homocysteine was measured in 189 cardiac transplant recipients and in healthy controls, as were concentrations of folate, vitamin B12, vitamin B6, and creatinine. RESULTS: Homocysteine concentrations were higher in recipients than controls (19.1+/-13.0 vs. 11.0+/-3.0 micromol/L, P<0.01), and hyperhomocysteinemia (>90th percentile for controls, 14.6 micromol/L) was seen in 68% of recipients (P<0.01). Folate and vitamin B6 concentrations were lower (5.9+/-4.2 vs. 7.9+/-4.2 pmol/L and 40+/-25 vs. 84+/-77 nmol/L, respectively; P<0.01 for both). Folate and vitamin B6 deficiencies were seen in 10.8% and 17.91% of recipients, respectively (P<0.01). Hyperhomocysteinemia was more frequent in patients with vascular complications after transplantation than in those without (79.2% vs. 63.8%, P<0.05). CONCLUSIONS: Elevated plasma homocysteine and deficiencies of folate and vitamin B6 are common in transplant recipients. A high homocysteine concentration was more common in patients with vascular complications. Prospective studies are now required to evaluate the role of these abnormalities as risk factors for the atherothrombotic complications of transplantation.

Arteriosclerosis↗
PubMed1998

Low circulating folate and vitamin B6 concentrations: risk factors for stroke, peripheral vascular disease, and coronary artery disease. European COMAC Group.

BACKGROUND: A high plasma homocysteine concentration is a risk factor for atherosclerosis, and circulating concentrations of homocysteine are related to levels of folate and vitamin B6. This study was performed to explore the interrelationships between homocysteine, B vitamins, and vascular diseases and to evaluate the role of these vitamins as risk factors for atherosclerosis. METHODS: In a multicenter case-control study in Europe, 750 patients with documented vascular disease and 800 control subjects frequency-matched for age and sex were compared. Plasma levels of total homocysteine (before and after methionine loading) were determined, as were those of red cell folate, vitamin B12, and vitamin B6. RESULTS: In a conditional logistic regression model, homocysteine concentrations greater than the 80th percentile for control subjects either fasting (12.1 micromol/L) or after a methionine load (38.0 micromol/L) were associated with an elevated risk of vascular disease independent of all traditional risk factors. In addition, concentrations of red cell folate below the lowest 10th percentile (<513 nmol/L) and concentrations of vitamin B6 below the lowest 20th percentile (<23.3 nmol/L) for control subjects were also associated with increased risk. This risk was independent of conventional risk factors and for folate was explained in part by increased homocysteine levels. In contrast, the relationship between vitamin B6 and atherosclerosis was independent of homocysteine levels both before and after methionine loading. CONCLUSIONS: Lower levels of folate and vitamin B6 confer an increased risk of atherosclerosis. Clinical trials are now required to evaluate the effect of treatment with these vitamins in the primary and secondary prevention of vascular diseases.

Adult↗
PubMed1998

Prospective study of hyperhomocysteinemia as an adverse cardiovascular risk factor in end-stage renal disease.

BACKGROUND: Retrospective and case-control studies show that hyperhomocysteinemia is an independent risk factor for atherosclerosis in patients with end-stage renal disease. We studied prospectively the association between total homocysteine and cardiovascular outcomes. METHODS AND RESULTS: In all, 167 patients (93 men, 74 women; mean age, 56.3+/-14.7 years) were followed for a mean duration of 17.4+/-6.4 months. Cardiovascular events and causes of mortality were related to total homocysteine values and other cardiovascular risk factors. Cox regression analysis was used to identify the independent predictors for cardiovascular events and mortality. Fifty-five patients (33%) developed cardiovascular events and 31 (19%) died, 12 (8%) of cardiovascular causes. Total plasma homocysteine values ranged between 7.9 and 315.0 micromol/L. Levels were higher in patients who had cardiovascular events or died of cardiovascular causes (43.0+/-48.6 versus 26.9+/-14.9 micromol/L, P=.02). The relative risk (RR) for cardiovascular events, including death, increased 1% per micromol/L increase in total homocysteine concentration (RR, 1.01; CI, 1.00 to 1.01; P=.01). CONCLUSIONS: These prospective observations confirm that hyperhomocysteinemia is an independent risk factor for cardiovascular morbidity and mortality in end-stage renal disease, with an increased RR of 1% per micromol/L increase in total homocysteine concentration. Interventional studies are needed to evaluate the possible effects of modifying this risk factor in these patients.

Adult↗
PubMed1998

UKCCSG's germ cell tumour (GCT) studies: improving outcome for children with malignant extracranial non-gonadal tumours--carboplatin, etoposide, and bleomycin are effective and less toxic than previous regimens. United Kingdom Children's Cancer Study Group.

BACKGROUND: We report the efficacy and late effects of carboplatin, etoposide, and bleomycin (JEB) for extracranial non-gonadal tumours (GCII, 1989-95) compared with the 5 previous regimens (GCI, 1979-1988) consisting of 3 vincristine, actinomycin, and cyclophosphamide (VAC) and 2 platinum-based protocols. METHODS AND RESULTS: Median follow-up for 52 patients in the GCI study and 46 in GCII was 105 and 48 months, respectively. For GCI, 5- and 10-year actuarial survival was 63% (95% Confidence interval 50 to 75%) or 72% (57 to 83%) if 6 cases given low-dose VAC were excluded. For GCII, 5-year survival was significantly greater at 95% (83 to 99%), p = 0.01. Event-free survival was 46% at 5 years for GCI (33 to 59%) or 52% excluding the low-dose VAC cases (38 to 66%), while for GCII it was 87% (74 to 94%), p = 0.002. Five-year event-free survival of 21 children given cisplatin, etoposide, and bleomycin (BEP) in GCI was 57% (37 to 76%) compared with 87% (74 to 94%) for 46 given JEB in GCII, P = 0.02. Late effects in 30 evaluable survivors of GCI and 43 GCII included renal impairment in 6 in GCI and 0 in GCII and deafness in 11 and 4, respectively. Among 17 survivors of sacrococcygeal tumours treated in GCI, 4 have neuropathic bladder/bowel and another shortening of a leg. In GCII, 4 of 26 have neuropathic bladder/bowel with lower limb weakness in one. CONCLUSIONS: We found JEB to be more effective and less toxic than our previous regimens. Some survivors of sacrococcygeal tumours have neurological late effects.

Adolescent↗
PubMed1998

Wife caregivers' and supportive others' perceptions of the caregivers' health and social support.

Perceptions of health and social support held by 75 wives caring for their mentally impaired husbands at home were compared with those of 75 supportive others, that is, secondary caregivers. Ratings by the two groups were significantly correlated, suggesting that the reports of wife caregivers may be considered valid. Supportive others rated physical help received by wife caregivers significantly higher than did the caregivers. Nondepressed caregivers perceived themselves to be significantly healthier than their supportive others perceived them. Depressed caregivers reported larger social networks than did their supportive others. Findings point to the importance of gaining the perspectives of both primary and secondary caregivers in order to understand the total reality of the caregiving situation.

Adult↗
PubMed1998

Semantic memory in Alzheimer's disease: representativeness, ontologic category, and material.

Alzheimer's disease (AD) patients with semantic memory difficulty and AD patients with relatively preserved semantic memory named pictures and judged the category membership of words and pictures of natural kinds and manufactured artifacts that varied in their representativeness. Only semantically impaired patients were insensitive to representativeness in their category judgments. AD subgroup judgments did not differ for natural kinds compared to manufactured artifacts nor for words compared to pictures. AD subgroup differences could not be explained by dementia severity, memory, reading, and visuoperception. The similarity process for relating coordinate members of a taxonomic category contributes to the normal appreciation of word and picture meaning, and this process is compromised in AD patients with semantic difficulty.

Aged↗
PubMed1998

High plasma homocysteine: a risk factor for vascular disease in the elderly.

Homocysteine is an intermediate compound formed during the metabolism of methionine. Several studies have shown that plasma homocysteine concentrations rise with age. Overt or borderline deficiencies of folate, vitamin B12 or B6 and possibly age-related kidney dysfunction are the major causes of homocysteine elevation in the elderly population. Multiple case-control and prospective studies have shown that a high plasma homocysteine concentration is an independent risk factor for cardiovascular diseases; this association persists in the elderly. Supplementation with folic acid either alone or with vitamins B12 and B6 can lower plasma homocysteine. Intervention studies to assess the effects (if any) of such treatment on prognosis are now in progress in patients with vascular disease.

Aged↗