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Biomedical subjects

N Robinson

Publications and source records attributed to N Robinson.

At least 109 records · Page 6Linked to original sources
PubMed1989

Employers' attitudes to diabetes.

In order to examine the knowledge and attitude of employers to diabetes and diabetic employees, a questionnaire was sent to a random sample of approximately 2500 businesses and industries in eight different areas of the United Kingdom. Information was collected on the employment of people with diabetes, such as sickness absence, suitability of types of job for the diabetic person, the proportion of people with diabetes registered as disabled, and the provision of pension schemes. Only 1% of firms claimed that they would not consider a person with diabetes for employment within the firm. Nearly a third of employers did not know whether they employed anyone with diabetes. Over a quarter of the manufacturing industries reported some jobs that were unsuitable and 8% reported certain unfavourable job conditions for a diabetic employee such as shift work, working at heights, strenuous work, etc. A total of 7% of those firms with a diabetic employee reported that diabetic workers were more often absent from work due to sickness and 16% of firms employing a diabetic person did not allow paid time off for clinic visits. The attitude of the majority of employers seemed to indicate that diabetes in itself does not limit employment prospects since most people with diabetes have few problems arising from their condition and can make good employees in a range of occupations.

Absenteeism↗
PubMed1989

Unemployment and diabetes.

Unemployment was examined in a random sample of diabetic clinic attenders and a group of non-diabetic control subjects aged 17-65 years, selected from eight different centres in Great Britain. Data on employment were obtained using a postal questionnaire and medical details were collected from diabetic clinic notes. Out of a 61% response rate, 22% of males and 12% of females with diabetes were unemployed compared with 8 and 5% of the control group (both p less than 0.001). A greater percentage of people with diabetes were economically inactive, that is retired, unable to work, ill or housewives compared with the control group (29 vs 14%, p less than 0.001). Young people with diabetes (16-25 years) had the highest rates of unemployment. A matched pairs analysis confirmed that diabetic men had higher unemployment rates than their controls (14 vs 7%, p less than 0.001). Comparisons were made between unemployment rates for the eight geographical areas and published unemployment statistics; unemployment rates were significantly higher for men with diabetes except at one centre. A stepwise multiple logistic regression analysis indicated that variables which were predictive of unemployment were similar to those expected for people without diabetes. Unemployment is apparently a problem for the person with diabetes, especially for the young.

Adolescent↗
PubMed1989

Infrequency of blacks among patients having carotid endarterectomy.

We reviewed demographic data on patients having 2,256 carotid endarterectomies in eight large hospitals in North Carolina to determine the frequency of blacks among these patients. Blacks comprised only 4.6% of the patients having carotid endarterectomy even though they comprised 26% of all patients discharged and 22% of the general population of the state. Data from the National Inpatient Profile of the Commission on Professional and Hospital Activities, which represents patients discharged from short-term, nonfederal hospitals throughout the United States, show that nationwide, blacks comprise only 2.7% of the patients having carotid endarterectomy, whereas they comprise 12.0% of all patients discharged, 12.1% of the general population, and 10.7% of patients discharged following Class I surgical procedures. Blacks have only 67 carotid endarterectomies per 100,000 patients discharged; this rate is five or more times higher in whites. Among black patients having carotid endarterectomy, women predominate, whereas men predominate among white patients having carotid endarterectomy (p = 0.006). The underrepresentation of blacks among patients having carotid endarterectomy lends support to the concept that carotid vascular disease in blacks is distributed intracranially rather than extracranially as opposed to the extracranial rather than intracranial distribution in whites.

Adult↗
PubMed1988

Nicotine gum: chew rate, subjective effects and plasma nicotine.

Two studies were conducted to assess the effects of varying the rate at which single pieces of nicotine gum (4 mg) were chewed. In each study, six cigarette-deprived volunteers were tested during four sessions. In each session, they were required to chew the gum for 10 min at varying rates; a variety of self-report and physiologic responses were recorded before and after chewing. All chewed gum was analyzed for amount of nicotine extracted, and blood samples were collected for nicotine analysis. Additionally, in Experiment 2, a measure of masticatory pressure was employed to assess the intensity of chewing and to empirically verify the number of chews. In both studies, we found a weak, but direct, relation between chew rate and the amount of extracted nicotine. Experiment 2 revealed a probable cause of the weaker than expected "dose-effect" function: subjects showed compensatory changes in behavior by chewing slower than instructed in the high rate conditions, and by chewing faster than instructed in the low rate conditions. Thus, despite instructions to vary chew rates across an 8-fold range, actual chew rate varied by only 2.2-fold. Intensity of chewing remained constant across conditions. Taken together, the findings suggest that rate of chewing nicotine gum can make a difference in the amount of nicotine extracted from the gum; however, compensatory changes in chew rate may attenuate attempts to systematically vary nicotine dose in this manner.

Adult↗
PubMed1988

Depression and diabetes.

The incidence and prevalence of depression in diabetic patients in the United Kingdom is unknown. Since depression may influence blood glucose control which in turn may be related to the development of diabetic complications, it is important to estimate its prevalence in diabetic patients. The prevalence of depression was investigated in a group of Caucasian and West Indian, insulin-(IDDM) and non-insulin-dependent (NIDDM) adult diabetics and a non-diabetic comparison group. Prevalence of depression was 8.5% for both groups and a further 19.2% and 14.6%, respectively, had borderline depression. Presence of depression was unrelated to sex, ethnic group, duration or type (IDDM or NIDDM) of diabetes and social class but significantly related to type of accommodation, marital status, and amount of social contact. A higher percentage of diabetics with psychiatric symptoms had one or more current complications compared to 'normal' diabetics. Diabetics suffer from a similar amount of depression to non-diabetics, but psychiatric symptoms may be related to the frequency of diabetic complications.

Adult↗
PubMed1988

Computer algorithm for modeling transmission over one or two conduction pathways through AV node.

The goal of this study was to develop and test models of conduction through the atrioventricular node, particularly to encompass possible transmission over multiple pathways. Output from the atrioventricular node was related to its input, the variable coupling interval of a single extrastimulus introduced to scan diastole during programmed atrial stimulation. Trials were performed three times in 15 patients after pacing for eight beats at 100 beats/min. Hyperbolic and exponential functions were used to model trial data. For conduction over a single pathway, the standard error of the estimate was less with the exponential than with the hyperbolic model. The preferred exponential model had the general form A2H2 = K1 + K2 exp(-A1A2/K3), with K1, K2, K3 being the parameters fitted. The algorithm describing transmission over two pathways minimized sums of squares of deviations from two such exponential functions, with potential "bifurcation" points between the functions being those farthest from the computed single curve of best fit. The model predicted (R2 greater than 0.90) that 43% of the trials showed single conduction pathways and the remaining 57% showed dual pathways. A cardiologist who independently examined the data discarded eight trials because of insufficient data or scatter and agreed with presence of two pathways and the point of discontinuity in plots in 81% of trials. The reasons for discordance were minor and thus the model was reasonably verified.

Adolescent↗
PubMed1986

Whole body oxygen utilization during acute carbon monoxide poisoning and isocapneic nitrogen hypoxia.

Carbon monoxide (CO) poisoning occurs frequently in victims of enclosed space fires, resulting in the formation of carboxyhemoglobin (COHb). Based on in vitro studies it has been suggested that CO poisoning causes a left shift of the oxyhemoglobin dissociation curve, decreasing peripheral oxygen extraction and exacerbating hypoxic injury. Formation of carboxycytochrome oxidase has also been postulated to act as a toxin by blocking cellular oxygen utilization. The effects of in vitro CO poisoning were evaluated in studies of 12 anesthetized, paralyzed dogs ventilated at 150 cc/kg/min. Six were subjected to CO poisoning by ventilation with a 0.5% CO in air inspirate. Six were ventilated with a mixture of air and nitrogen (N2) to produce a similar decrement of arterial oxyhemoglobin (aO2Hb) saturation. Arterial and mixed venous blood gases, thermal dilution cardiac output, and spectrophotometric arterial and mixed venous O2Hb and COHb saturation were measured. Oxygen consumption (VO2) and extraction (EXT) were calculated from these measurements and the CO and N2 groups were compared by ANOVA and Wilcoxon sign rank test as oxyhemoglobin was progressively decreased. There were no significant differences in VO2 or O2 EXT in these two sets of animals subjected to equivalent reductions of arterial oxyhemoglobin despite the fact that CO poisoning was the mode of desaturation in one group. These findings suggest that CO poisoning is primarily a hypoxic lesion caused by replacement of O2Hb by COHb. Effects predicted from in vitro studies may not be manifest in vivo due to physiologic responses active in the whole organism. This may have implications for the resuscitation of CO-injured patients.

Animals↗
PubMed1985

Prognostic factor study of survival after enucleation for juxtapapillary melanomas.

We reviewed 242 cases of choroidal and ciliary body melanoma that were treated by enucleation to determine the importance of juxtapapillary location as a prognostic factor for tumor-related deaths. Analysis involved Kaplan-Meier survival curves and Cox proportional hazards analysis. Patients with juxtapapillary tumors had a worse prognosis than those with tumors in other locations (64% vs 78% five-year survival), but the difference was not statistically significant. Juxtapapillary location was not an independent risk factor on Cox multivariate analysis. Risk factors included number of epithelioid cells per high-power field, largest tumor dimension, location of the tumor's anterior margin, and invasion to the line of transection. In 63 cases (26%), the tumor was in contact with the optic disc. For these juxtapapillary tumors, we also evaluated the prognostic importance of six variables relevant to juxtapapillary location. On univariate analysis, tumor height at the disc margin, subarachnoid space invasion, and postlaminar optic nerve invasion were significantly related to survival, while disc compression by tumor, prelaminar optic nerve invasion, and extent of disc perimeter surrounded by tumor were not. On Cox multivariate analysis, however, none of these six variables was an independent risk factor. Risk factors for juxtapapillary tumors included number of epithelioid cells per high-power field and location of the tumor's anterior margin.

Choroid Neoplasms↗
PubMed1985

Role of life events and difficulties in the onset of diabetes mellitus.

The role of stressful life and difficulties in the onset of insulin-dependent (Type 1) diabetes mellitus was examined in a group of 13 newly diagnosed diabetics and sibling and neighbourhood controls. Subjects aged between 17-34 years, were interviewed and information was collected over the 3 year period preceding clinical diagnosis of diabetes. Diabetics had a higher frequency of one or more severe life events prior to diagnosis i.e. 77% compared with their siblings and age/sex matched controls i.e. 39% and 15% respectively. Diabetics also had a higher percentage of 2 or more severe life events prior to diagnosis i.e. 54% compared with 8% for siblings and 8% for neighbourhood controls. The frequency of severe difficulties was also higher for diabetics--46% compared with 13% and 23% for siblings and neighbourhood controls respectively. Stressful events and difficulties may be triggering factors involved in the aetiology of insulin-dependent diabetes.

Adolescent↗
PubMed1984

Biochemical genetic analysis of formycin B action in Leishmania donovani.

Formycin B is cytotoxic toward Leishmania and is a potential chemotherapeutic agent for leishmaniasis. In order to determine the mechanism of action of formycin B, we have isolated and characterized clonal populations of formycin B-resistant Leishmania donovani. These formycin B-resistant clones are also cross-resistant to formycin A and allopurinol riboside-mediated growth inhibition. Incubation of the formycin B-resistant cells with [3H]formycin B indicates that, unlike wild type cells, the resistant populations cannot accumulate phosphorylated metabolites of exogenous [3H]formycin B. This is due to a defective transport system for formycin B in the resistant cells. However, wild type and mutant cells incorporate [3H]formycin A equally efficiently into [3H]formycin A-containing nucleotides and into RNA. These data suggest that formycin B cytotoxicity in Leishmania is not mediated by its incorporation as the adenosine analog into RNA. A plausible alternative hypothesis is proposed for the mechanism of action of the pyrazolo (4,3-d)pyrimidine C-nucleosides based upon depletion of an essential intracellular metabolite.

Allopurinol↗
PubMed1984

Modified tissue culture medium for corneal storage I. Investigation of the effect of antibiotics on bacterial contamination.

A series of experiments were performed to determine the effect of modified tissue culture medium (MTCM), temperature, time, and antibiotics on the replication of Staphylococcus epidermidis and Pseudomonas aeruginosa. A known inoculum of the organisms (usually 10(6)/mL) was introduced, and the recovery of viable organisms was compared by different methods of culturing, including techniques of diluting, inactivating, or removing the antibiotic from the system. The invalidity of techniques that failed to remove the antibiotic from the system was substantiated. The newly developed antibiotic removal device was superior to all other culturing techniques. Penicillin G potassium was ineffective in the MTCM system, and gentamicin reagent solution was not uniformly effective against a gentamicin-sensitive strain of P aeruginosa. Placement of the MTCM at room temperature for two hours enhanced the antibacterial activity of gentamicin, although organisms may still be recovered in small numbers.

Anti-Bacterial Agents↗
PubMed1984

Modified tissue culture medium for corneal storage. II. Investigation of the effect of the corneoscleral rim on bacterial contamination.

Our previous experiments showed the effect of time, temperature, and antibiotics on replication of Staphylococcus epidermidis and Pseudomonas aeruginosa introduced into the modified tissue culture medium (MTCM). Penicillin G potassium was ineffective in the MTCM, and gentamicin sulfate was not uniformly effective against a gentamicin-sensitive organism. Placement of the MTCM at room temperature for two hours enhanced the antibacterial activity of gentamicin. Culturing techniques that fail to remove the antibiotic from the system are invalid. Experiments reported herein showed that the addition of the corneoscleral rim (or extraneous protein) prolongs the survival of these same organisms. Organisms can survive in the MTCM despite high concentrations of gentamicin. Maintaining the MTCM at room temperature for two hours after storage at 4 degrees C effectively reduces but may not completely eliminate the recovery of organisms. The antibiotic removal device may be superior to other methods for recovering viable organisms.

Animals↗
PubMed1984

Neuronal and oligodendrocytic response to cortical injury: ultrastructural and cytochemical changes.

A needle wound was made in the adult rat cerebral cortex. Responses of neurons and oligodendrocytes at the site of injury were followed over a period of 450 days and correlations made between morphological and enzyme cytochemical changes to clarify some phenomena previously unresolved. Evidence from acid phosphatase activity in degenerating neurons showed no increase in the number of cytochemically stained lysosomal profiles nor changes in the subcellular localization of the acid phosphatase reaction product. Our observations indicated that the majority of dying neurons were not digested by their own acid phosphatase 'autodigestion' but by the process of heterodigestion. The time-course study revealed that not all the traumatized neurons were eliminated but some persisted permanently in an attenuated 'atrophic' state. The atrophic neurons were small in size with low cytoplasmic-nuclear ratios and exhibited low levels of glucose-6-phosphatase and cytochrome oxidase activities. The acid phosphatase activity was slightly increased as evidenced by cytochemically stained hypertrophic Golgi cisternae and a slight increase in the number of lysosomes. The low level of enzyme activities concerned with carbohydrate metabolism reflected the low metabolic activity in atrophic neurons whilst an increase in Golgi-lysosomal enzyme activity suggested some anabolic process necessary for their survival. Oligodendrocytes displayed only minor changes in morphology, and their glucose-6-phosphatase and cytochrome oxidase activities were normal, suggesting that these cells have little or no involvement in the repair of a cerebral wound. The absence of significant changes in lysosomal acid phosphatase activity indicated a minimal role, if any, of oligodendrocytes in the process of phagocytosis.

Acid Phosphatase↗
PubMed1984

Social class and risk factors for vascular disease in diabetes.

Mortality statistics for England and Wales and for the U.S.A. indicate that death rates from diabetes mellitus are higher in the lower socioeconomic classes. In an attempt to explain this mortality difference, social-class differences in possible risk factors for the large- and small-vessel disease complications of diabetes have been examined in 95 insulin dependent diabetics (IDDs) and 79 non-insulin dependent diabetics (NIDDs) and comparative data obtained from 155 non-diabetic controls. Control males in the lower social class group were significantly shorter, more obese, smoked more and had lower Type A behaviour scores. Lower class female controls had significantly higher serum cholesterol levels. For the diabetic groups there were no social class differences in either fasting blood glucose levels or the prevalence of diabetic complications. Lower class NIDDs were significantly shorter and had lower Type A scores. This group also had higher mean cholesterol levels and smoked more, but these differences did not achieve statistical significance. Male IDDs showed no significant social class differences in possible risk factors but lower class females IDDs smoked more and had higher mean triglyceride levels. This concentration of risk factors for vascular disease in the diabetics of lower social class, particularly the NIDDs, may partly explain the increased mortality found in this group.

Adult↗