Retinal Thy-1 expression during development

PURPOSE

To evaluate the developmental expression of Thy-1 in the retina. Thy-1, the most abundant mammalian neuronal surface glycoprotein, is likely to play a significant role in retinal development. In the mammalian retina, it is found predominantly, if not exclusively, on retinal ganglion cells.

METHODS

Rat retinae of various ages were stained immunohistochemically for Thy-1 with 2G12, a monoclonal Thy-1 antibody. Sections were analyzed digitally to quantify bound antibody. Using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR), the expression of Thy-1 protein was compared with the levels of mRNA detected.

RESULTS

Thy-1-dependent fluorescence was detected in rat retinae from birth, albeit at low levels. Thy-1 labeling was localized predominantly to the ganglion cell layer. Minimal, fine patterns of linear and reticular fluorescence were noted in the inner nuclear layer. Thy-1 levels reached a maximal level at approximately postnatal day 14. RT-PCR measurements showed a similar time course for the increase in Thy-1 expression.

CONCLUSIONS

The Thy-1 antigen is present in the inner retina at birth. Its level increases steadily after birth and peaks during the second week of life. Thy-1 expression is approximately coterminous with synaptogenesis of the inner plexiform layer and may play a role in synaptogenesis of the inner retina or in other developmental milestones in the formation of the visual system.

The relationship between socioeconomic status and diabetes control and complications in the EURODIAB IDDM Complications Study

OBJECTIVE

To determine whether there are socioeconomic differences in diabetes control and complications in people with IDDM.

RESEARCH DESIGN AND METHODS

We conducted a prevalence survey of 1,217 men and 1,170 women with IDDM age 25-60 years from European clinics. Age at completion of education defined socioeconomic status: < or = 14 years defined those with primary education; 15-18 years, as secondary education; and > 19 years, as college education. Glycemic control, lipids, diet, retinopathy, neuropathy, and heart disease were assessed centrally.

RESULTS

People with a primary education were older and had diabetes for longer than those with a college education. The mean percentage of HbA1c was worst in the primary-educated men (6.6 vs. 6.1%, P = 0.0007 for trend) and women (6.5 vs. 6.0%, P = 0.0007). Total cholesterol level was higher in primary-educated than in college-educated men (5.6 vs 5.3 mmol/l, P = 0.002), as was triglyceride level (1.23 vs. 1.02 mmol/l, P = 0.0001). College-educated people were the least likely to be current smokers (P < 0.0001), and were most likely to partake in vigorous exercise (P < 0.001). Surprisingly, There was little difference in the prevalence of heart disease by educational status in men, while it was highest in the least educated women, but proliferative retinopathy was more common in primary- than in college-educated men (16 vs 10%, P = 0.04) as was macroalbuminuria (15 vs 9%, P = 0.03). Glycemic control could not fully account for these differences.

CONCLUSIONS

Healthy lifestyles are more prevalent in better educated men and women with IDDM, but these are not reflected in heart disease prevalence in men. The lower prevalence of severe microvascular complications in better educated men, unaccounted for by better glycemic control, requires further investigation.

Ethnic differences in mortality from cardiovascular disease in the UK: do they persist in people with diabetes?

STUDY OBJECTIVE

To determine whether ethnic differences in cardiovascular disease mortality persist in people with non-insulin-dependent diabetes mellitus.

DESIGN

This was an ecological study in which routine mortality data from 1985-86, which coded all mentioned causes of death, provided the numerator. The UK population derived from 1981 census formed the denominator.

SETTING

United Kingdom.

PARTICIPANTS

Records of all deaths in people aged 45 years and above were extracted if diabetes was mentioned anywhere on the death certificate. The denominator was aged five years to approximate to the 1986 population. Mortality rates where a cardiovascular underlying cause was given were compared between South Asians, African-Caribbeans, and those born in England and Wales. The latter group formed the standard for directly standardised rate ratios.

MAIN RESULTS

Mortality from heart disease was approximately three times higher in diabetic South Asian born men and women than in those with diabetes born in England and Wales. This ethnic difference was greatest in the younger age group. Conversely, stroke mortality rates in African-Caribbeans were 3.5-4 times higher than those in the England and Wales population. Despite this high mortality from stroke, ischaemic heart disease death rates were not high in African-Caribbean men.

CONCLUSIONS

Ethnic differences in cardiovascular mortality persisted and were greater in those with diabetes. Thus the high risk of heart disease should be targeted for intervention in South Asians, and the high rates of stroke targeted in African-Caribbeans.

The use of the Micral-Test strip to identify the presence of microalbuminuria in people with insulin dependent diabetes mellitus (IDDM) participating in the EUCLID study

In IDDM, microalbuminuria (urinary albumin excretion rate (AER) of 20-200 micrograms/min) is a predictor of persistent proteinuria and diabetic nephropathy. Early intervention may prevent or reduce the rate of progression of renal complications. The Micral-Test strip can be used to establish a semi-quantitative estimate of AER. We assessed the field performance of the Micral-Test strip in detecting microalbuminuria in the EUCLID study, an European wide, 18 centre study of 530 IDDM participants, aged 20 to 59 years. People with macroalbuminuria were excluded. On entry, all participants had albumin concentrations from two overnight urine collections measured by a central laboratory, and the corresponding Micral-Test performed on the two collections locally. a cut off of > or = mg/l albumin from the first Micral-Test, to detect a centrally measured albumin concentration > or = 20 mg/l, yielded 29 (5.8%) false negative results and 58 (11.6%) false positive results (sensitivity 70%, specificity 87%). The mean AER, from two collections, was compared with the corresponding 'pooled' Micral-Test results (mean of the two readings). Receiver Operating Characteristic (ROC) curves were used to assess if there was a suitable 'pooled' Micral-Test result for screening microalbuminuria. A 'pooled' Micral-Test result (> or = 15 mg/l) was used to detect mean AER > or = 20 micrograms/min (sensitivity 78%, specificity 77%). This 'pooled cut-off' had already been used for screening on to the study and led to an over-estimate (154 vs. 77) of the true number of microalbuminuric participants on the study. In conclusion, our findings suggest that the Micral-Test strip is not an effective screening tool for microalbuminuria, using the 'pooled' result from two measurements did not improve the sensitivity of the test.

The relationship between pregnancy and long-term maternal complications in the EURODIAB IDDM Complications Study

Pregnancy is believed to exacerbate diabetes complications, although the degree to which this occurs, and the advice that should be given to women contemplating pregnancy is unclear. We examined 776 nulliparous and 582 parous women with Type 1 diabetes from a cross-sectional study performed in 31 European centres. Glycaemic control was better in parous women. Age and duration adjusted prevalence of microalbuminuria was similar in parous and nulliparous women, but macroalbuminuria was lower in parous women (6% versus 10%, p < 0.0001). Prevalence of all retinopathy was lower in parous women (34% in women who had two or more pregnancies, 45% in women who had one), compared with 48% in nulliparous women (chi 2 for trend = 47.1, p < 0.0001). Proliferative retinopathy was lower in parous (8% and 7%, respectively) compared with nulliparous women (16%, chi 2 for trend = 52.2, p < 0.0001). These differences persisted when adjusted for glycaemic control. Excluding referrals for pregnancy, parous women were more likely to have been referred to the diabetes clinic with complications than nulliparous women (p = 0.001). It is unlikely that our findings can be explained by women with complications being advised against pregnancy, or by the better glycaemic control in parous women. Equivalent levels of microalbuminuria and background retinopathy in parous and nulliparous women suggests that pregnancy may not exacerbate these early complications.

Mortality and morbidity associated with body weight in people with IDDM. The WHO Multinational Study of Vascular Disease in Diabetes

OBJECTIVE

Strict glycemic control in people with insulin-dependent diabetes mellitus (IDDM) reduces the risk of microvascular complications, but improvements in control are also associated with weight gain. Fears about the mortality risks of obesity may limit the acceptability of tight control. Therefore, we examined morbidity and mortality risks associated with body weight in people with IDDM.

RESEARCH DESIGN AND METHODS

This was a cohort study of 644 men and 576 women with IDDM from nine centers worldwide. Baseline examinations were performed in 1975-1977, and mortality follow-up continued until 1988.

RESULTS

Body weight was positively associated with blood pressure and, in men, with cholesterol. Fasting blood glucose was higher in the most obese groups in women only. There were 204 deaths among the men and 148 among the women. There was a reverse J-shaped relationship between body weight and all-cause mortality, with the highest mortality rates occurring in the leanest body mass index (BMI) category. The age-, duration-, and center-adjusted mortality rate ratio (95% confidence interval) comparing BMI category < 20 kg/m2 with BMI category > or = 22 and < 24 kg/m2 was 2.64 (1.59-4.38) in men and 1.54 (0.77-3.06) in women. Additional adjustment for smoking, blood pressure, glucose, cholesterol, and proteinuria did not qualitatively alter these findings.

CONCLUSIONS

We conclude that except in very lean people with IDDM, body weight is not significantly associated with mortality. Thus, efforts to improve glycemic control should not be restricted by concerns about the effects of weight gain on mortality.

Mortality risk by body weight and weight change in people with NIDDM. The WHO Multinational Study of Vascular Disease in Diabetes

OBJECTIVE

Care guidelines for people with non-insulin-dependent diabetes mellitus (NIDDM) emphasize the importance of weight loss in reducing mortality risk. However, existing evidence regarding the relationship between weight and mortality and the effects of weight change is conflicting. We examined these relationships in the World Health Organization Multinational Study of Vascular Disease in Diabetes.

RESEARCH DESIGN AND METHODS

This was a cohort study of 1,416 men and 1,544 women. Baseline examinations were performed in 1975 through 1977, a morbidity follow-up was performed in 1983, and a mortality follow-up continued until 1988. Data were analyzed according to geographical groups: Europeans, East Asians, and Native Americans. The relationship between weight change and mortality was analyzed for Europeans only.

RESULTS

Generally, body mass index (BMI) was positively associated with age, blood pressure, and cholesterol but was negatively associated with duration of diabetes, prevalence of retinopathy, and use of insulin. There was no clear relationship between BMI and mortality across the geographical groups. In Europeans, weight loss in the leanest subjects at baseline (BMI < 26 kg/m2) was associated with a threefold increase in mortality risk compared with those who had maintained a steady weight (relative risk [RR] 3.05, 95% confidence interval [CI] 1.26-7.36). Only in the most obese group was weight loss associated with a reduction in mortality risk (BMI > 29 kg/m2, RR 0.84, 95% CI 0.40-1.74).

CONCLUSIONS

The positive association of BMI with age, blood pressure, and cholesterol and the negative association with duration of diabetes, retinopathy, and use of insulin may explain why there is no strong relationship between BMI and mortality in NIDDM. Weight loss, particularly in the relatively lean diabetic person, may be associated with an increased mortality risk.

Hypertensive retinopathy in Afro-Caribbeans and Europeans. Prevalence and risk factor relationships

The prevalence of hypertension is particularly high in people of black African descent throughout the world, and the consequences of hypertension, such as hypertensive heart and renal disease and stroke, are also more common. But there is little consensus on whether hypertensive retinopathy follows a similar pattern. We determined the prevalence of hypertensive retinopathy and its relationships with resting and ambulatory blood pressure in a population study of Afro-Caribbeans and Europeans aged 40 to 64 years in London, UK. Retinal photographs of 651 participants were graded for hypertensive retinopathy. Age- and sex-standardized prevalence of retinopathy was 11% (95% confidence interval, 8% to 14%) in Europeans and 21% (95% confidence interval, 16% to 26%) in Afro-Caribbeans (P < .001), respectively. This ethnic difference in prevalence was greatest in normotensive women (8% in Europeans versus 20% in Afro-Caribbeans, P < .001). Resting systolic pressure was 8 mm Hg higher in normotensive Afro-Carribean compared with European women, but this could not fully account for the ethnic difference in the prevalence of retinopathy. Examination of the different relationships of age and resting and ambulatory blood pressures with hypertensive retinopathy showed that these relationships were strongest in European women and weakest in Afro-Caribbean women. We conclude that hypertensive retinopathy is more common in Afro-Caribbeans, particularly women, and that ethnic differences in resting blood pressure cannot fully account for this. The relatively weak relationship between resting and ambulatory blood pressures and retinopathy in Afro-Caribbeans suggests that factors other than blood pressure determine the high rates of hypertensive retinopathy in this group.

The relationship between smoking and microvascular complications in the EURODIAB IDDM Complications Study

OBJECTIVE

To examine the relationship between smoking and both glycemic control and microvascular complications in patients with insulin-dependent diabetes mellitus (IDDM).

RESEARCH DESIGN AND METHODS

This was a prevalence survey of 3,250 men and women aged 15-60 years with IDDM from 31 diabetes centers in 16 European countries. Participants completed a questionnaire, had retinal photographs taken, and performed a 24-h urine collection. HbA1c, frequency of hypoglycemic and ketoacidotic episodes, urinary albumin excretion rates, and retinopathy were compared by smoking category.

RESULTS

The prevalence of smoking was 35% in men and 29% in women. Current smokers had poorer glycemic control and, among men, were more likely to have had a ketoacidotic episode than were those who never smoked. Ex-smokers had equivalent glycemic control and marginally more hypoglycemic episodes did than those who never smoked. Current smokers had a higher prevalence of microalbuminuria and total retinopathy than did those who never smoked. Ex-smokers had a higher prevalence of macroalbuminuria and proliferative retinopathy than did those who never smoked, but both had a similar prevalence of microalbuminuria. Adjustment for either current or long-term glycemic control could not fully account for these differences.

CONCLUSIONS

Smoking is associated with poorer glycemic control and an increased prevalence of microvascular complications compared with not smoking. Ex-smokers can achieve glycemic control equivalent to and have a prevalence of early complications similar to that of those who never smoked. We suggest that poorer glycemic control can account for some of the increased risk of complications in smokers, and that quitting smoking would be effective in reducing the incidence of complications. Urgent action is required to reduce the high smoking rates in people with IDDM.

Effect of mitomycin C and fluorouracil-supplemented trabeculectomies on the anterior segment

OBJECTIVES

To determine whether there is increased risk to the corneal endothelium when mitomycin C is used in trabeculectomy surgery instead of fluorouracil, and whether these agents play a role in accelerating cataract formation.

DESIGN, SETTINGS, AND PARTICIPANTS

We analyzed the corneal endothelium and the lens preoperatively and postoperatively in 30 eyes of 21 patients who underwent either a fluorouracil- or mitomycin C-supplemented trabeculectomy.

RESULTS

No significant differences were found between these two groups in the rate of cataract progression, magnitude of endothelial cell loss, or appearance of endothelial cell morphologic characteristics. Endothelial cell loss accounted for approximately 7% to 8% of the preoperative counts in both groups. In addition, four (27%) of 15 eyes in each group showed evidence of cataract progression as graded by the Lens Opacities Classification System II.

CONCLUSION

Fluorouracil- and mitomycin C-supplemented trabeculectomies cause similar changes in the lens and corneal endothelium.

Assessment of intraocular pressure by palpation

PURPOSE/METHODS

Corneal specialists may assess the intraocular pressure by palpation although this technique has never been validated. We explored the reliability of a tactile assessment of the intraocular pressure in comparison to Goldmann tonometry.

RESULTS/CONCLUSION

There was little correlation between tactile assessment of the intraocular pressure and tonometry. However, palpation was moderately successful in identifying most eyes (five of seven eyes) with an intraocular pressure greater than 30 mm Hg. Although palpation was generally inaccurate, it may serve as a warning for marked increases in intraocular pressure exceeding 30 mm Hg.

Assessing equity in access to health care provision in the UK: does where you live affect your chances of getting a coronary artery bypass graft?

STUDY OBJECTIVES

Equity should be monitored routinely for all health care services, but ideal studies for each service would be prohibitively expensive and time consuming. A simple, quick, and cheap method for the preliminary exploration of equity in health care provision using routine data was devised. This method was illustrated by examining whether coronary artery bypass graft (CABG) operations reflect socioeconomic differences in ischaemic heart disease (IHD) mortality.

DESIGN

Ecological comparison of operation rates was undertaken for CABG for 1991 and IHD mortality for 1981-85 by quartiles of Townsend deprivation score.

SETTING

North East Thames Regional Health Authority, London, UK.

SUBJECTS

All residents of this region aged 35-74 were the denominator population. Numerators were 26,834 IHD deaths and 1041 CABG operations for the defined time periods.

MAIN RESULTS

IHD mortality showed a steady, significant increase with increasing area deprivation scores for both men and women. CABG rate ratios increased linearly for women, while for men there was a U shaped pattern, being lowest for the second and third quartiles. This pattern was attenuated, but not abolished, when adjusted for geographical proximity to cardiothoracic surgical units. The ratio of CABG operations to IHD mortality by deprivation was relatively constant in women suggesting equitable provision. In men, this ratio was significantly lower for the third quartile.

CONCLUSIONS

Inequities may exist in the provision of CABG operations for men in this region and this finding should be the stimulus for further detailed studies. Other health care systems should also examine equity in provision.

From the surgery to the surgeon: does deprivation influence consultation and operation rates?

BACKGROUND

Concern about equity of access to health care has increased since the health care reforms implemented in the 1990s. Access to specialist health care is controlled by general practitioners; assessing and ensuring equity should therefore begin in general practice.

AIM

This study set out to determine whether there are socioeconomic differences in the relationship between expressed need for possible surgical intervention (consulting a general practitioner) and surgical provision.

METHOD

Information on the social class distribution of expressed need was obtained from the third national morbidity survey (1981-82) for 140,049 patients consulting a general practitioner. The conditions examined were: inguinal hernia, gallstones, tonsillitis, varicose veins, cataract and osteoarthritis. This expressed need was compared with the appropriate operation for all residents of North East Thames Regional Health Authority from January 1991 to July 1992 classified, according to area of residence, by the Townsend deprivation score.

RESULTS

The relationship between expressed need and provision by deprivation was concordant for some conditions, but discordant for others. For cataract and tonsillitis, there was an inverse U pattern between increasing deprivation and both patient consultation and operation ratios. For varicose veins, deprivation was associated with higher patient consultation and operation ratios. For hernia, gallstones and osteoarthritis, consultations increased with deprivation, but operation ratios were either unrelated to deprivation scores (hernia and gallstones) or decreased by deprivation score (hip operations).

CONCLUSION

There are marked socioeconomic differences in consultation ratios for these common conditions which may not be matched by operation ratios. For discordant comparisons, people in the most deprived quartiles were generally least likely to receive surgery despite being most likely to consult a general practitioner with symptoms. If validated, these findings have important implications for general practice and service providers.

Echocardiographic measures of left ventricular structure and their relation with rest and ambulatory blood pressure in blacks and whites in the United Kingdom

OBJECTIVES

This study attempted to determine whether people of black African descent have more left ventricular hypertrophy than those of white European descent and whether this can be explained by rest or ambulatory blood pressure.

BACKGROUND

Mortality associated with hypertension is higher in black populations than among whites, but differences in morbidity and their associations with blood pressure are inconsistent.

METHODS

We examined 1,166 black and white men and women 40 to 64 years old in a community survey in London, United Kingdom. Echocardiograms were obtained for all subjects and ambulatory blood pressure recordings for 319.

RESULTS

Adjusted for body size, ventricular septal thickness was greater in blacks than whites (p < 0.05), and cavity dimension was smaller (p < 0.05). In men, ventricular septal thickness was > 10 mm for 32% of whites and 53% of blacks; for women these figures were 14% and 38%, respectively. Relative wall thickness was greater in blacks (p < 0.01 for men and women), but left ventricular mass index was similar in the two ethnic groups. In men, hypertension resulted in an increase in wall thickness in both ethnic groups, but cavity dimension decreased in blacks and increased in whites. Wall thickness was higher in blacks than in whites for equivalent levels of either rest (p = 0.05) or ambulatory (p = 0.007) blood pressure.

CONCLUSIONS

Left ventricular mass index may not be valid for comparison between ethnic groups because this derived measure does not take into account ethnic differences in ventricular structural response to hypertension. Interventricular wall thickness may be more valid. Using this measure, we demonstrate greater ventricular hypertrophy in blacks than in whites, unexplained by differences in either rest or ambulatory blood pressure. The pattern of ventricular hypertrophy observed in blacks is associated with an increased mortality risk. Conventional blood pressure thresholds for instituting antihypertensive treatment may be too conservative for people of black African descent.

Median analysis of blood pressure for a sample including treated hypertensives

We consider the analysis of epidemiological studies in which the outcome of interest is a physiological disturbance (such as blood pressure) which may have been corrected by medical intervention (such as antihypertensive treatment). It is important to take account of such intervention in studying the determinants of hypertension. We recommend using the median as a measure of location and assuming that the underlying values of subjects under intervention lie above the median. Some well-established exact methods for simple problems are presented. An example is given in which the blood pressure differences between Afro-Caribbeans and Europeans are underestimated by about one-quarter if adjustment is not made for treated hypertensives.

Relationship of glucose intolerance to coronary risk in Afro-Caribbeans compared with Europeans

Afro-Caribbeans have low mortality rates from coronary heart disease, despite a high prevalence of diabetes mellitus. We examined 1166 Afro-Caribbean and European men and women aged 40-64 years in a community survey in London, UK. Prevalence of glucose intolerance (combining impaired glucose tolerance, new and known diabetes) was 31% in Afro-Caribbeans and 14% in Europeans (p < 0.001). In men, the prevalence of probable coronary heart disease was 6% in Afro-Caribbeans and 13% in Europeans (p < 0.01). Triglyceride was lower in Afro-Caribbeans than Europeans; in men, HDL cholesterol was higher. Afro-Caribbean men were less centrally obese, while Afro-Caribbean women were more centrally obese than their European counterparts. Fasting and 2-h insulin levels were higher in Afro-Caribbeans than Europeans. Glucose intolerance was associated with high triglyceride, low HDL cholesterol and central obesity in European but not in Afro-Caribbean men. In Europeans, fasting triglyceride was 1.49 mmol/l in normoglycaemic and 1.89 mmol/l in glucose intolerant men (p < 0.05), in Afro-Caribbean men triglyceride was 1.08 and 1.22 mmol/l, respectively. Waist hip ratio was 0.94 in normoglycaemic, and 0.98 in glucose intolerant European men (p < 0.001). In Afro-Caribbean men, waist hip ratio was 0.93 in both groups. At each level of insulin, glucose or central obesity, triglyceride was lower in Afro-Caribbean men and women than in Europeans. We speculate that despite high insulin levels, Afro-Caribbeans have a favourable lipoprotein pattern which persists in the presence of glucose intolerance, and may be related to body fat distribution.(ABSTRACT TRUNCATED AT 250 WORDS)

Equity in the NHS. Monitoring and promoting equity in primary and secondary care

Although need is often assumed to be the most important factor in determining the use of health services, there are many inequities in the provision and use of NHS services in both primary and secondary care. For example, existing data from district child health information services have been combined with census data for small areas to show wide variations in immunisation rates between affluent and deprived areas. Purchasers of health care are already responsible for assessing health needs and evaluating services, and the process of monitoring equity is a logical extension of these activities. Routine data sources used to collect activity data in both primary and secondary care can be used to assess needs for care and monitor how well these needs are met. Purchasers and providers should collaborate to improve the usefulness of these routine data and to develop a framework for monitoring and promoting equity more systematically.

Methods for epidemiological surveys of ethnic minority groups

OBJECTIVE--Research into the health of minority ethnic groups is often restricted by methodological difficulties. These include the lack of accurate population denominators, the choice of an appropriate sampling frame, correctly assigning ethnic group, and biases in techniques used for sampling and investigation. This article reviews the available sources or mortality and morbidity data, and assesses their uses and limitations for research involving ethnic minority groups. Suitable sampling frames and review methods used to assign ethnicity are discussed. Sources of bias are high-lighted and methods used to overcome these biases are presented. CRITERIA FOR INCLUSION OF ARTICLES--Articles have been chosen which best illustrate the problems encountered and show how these problems can be addressed. CONCLUSIONS--The increased documentation of ethnic origin on routine data sources is welcomed, but attention must be paid to ensuring that congruent definitions in data collection are used. The worrying consequences of the Commission of European Communities directive, which describes the need for explicit consent to be obtained from subjects before data is used for anything other than its original purpose, are discussed.

pH-dependent binding of synthetic beta-amyloid peptides to glycosaminoglycans

The senile plaques found within the cerebral cortex and hippocampus of the Alzheimer disease brain contain beta-amyloid peptide (A beta) fibrils that are associated with a variety of macromolecular species, including dermatan sulfate proteoglycan and heparan sulfate proteoglycan. The latter has been shown recently to bind tightly to both amyloid precursor protein and A beta, and this binding has been attributed largely to the interaction of the core protein of heparan sulfate proteoglycan with A beta and its precursor. Here we have examined the ability of synthetic A beta s to bind to and interact with the glycosaminoglycan moieties of proteoglycans. A beta(1-28) associates with heparin, heparan sulfate, dermatan sulfate, and chondroitin sulfate. The interaction of these sulfated polysaccharides with the amyloid peptide results in the formation of large aggregates that are readily sedimented by centrifugation. The ability of both A beta(1-28) and A beta(1-40) to bind glycosaminoglycans is pH-dependent, with increasing interaction as the pH values fall below neutrality and very little binding at pH 8.0. The pH profile of heparin-induced aggregation of A beta(1-28) has a midpoint pH of approximately 6.5, suggesting that one or more histidine residues must be protonated for binding to occur. Analysis of the A beta sequence reveals a consensus heparin-binding domain at residues 12-17, and this motif contains histidines at positions 13 and 14 that may be involved in the interaction with glycosaminoglycans.(ABSTRACT TRUNCATED AT 250 WORDS)

Lateral geniculate nucleus in glaucoma

To assess glaucomatous damage to the lateral geniculate nucleus of the thalamus, as well as to its magnocellular and parvocellular layers, we examined the autopsy sections of the lateral geniculate nucleus of individuals with and without glaucoma. Five patients with a documented history of glaucoma and five controls with no ophthalmic or chronic central nervous system disease were included in this study. Neurons were counted in autopsy sections of the lateral geniculate nucleus. Cells were counted in 40 random microscopic fields of the magnocellular and parvocellular layers respectively. The mean magnocellular cell density for the glaucoma group of 2.72 +/- 0.13 cells per square millimeter (mean +/- SEM) was significantly less than that for the control group of 3.76 +/- 0.13 cells per square millimeter (P < .001). There was no statistical difference in the parvocellular layer. These data suggest that glaucoma leads to greater loss of magnocellular tissue at the level of the lateral geniculate.

Resting and ambulatory blood pressure differences in Afro-Caribbeans and Europeans

To investigate why mortality from stroke in people of Afro-Caribbean origin is twice the average for England and Wales, we examined 1166 European and Afro-Caribbean people in London. Age-standardized median systolic blood pressure was 6 mm Hg higher (128 versus 122 mm Hg) in Afro-Caribbean than European men and 17 mm Hg higher (135 versus 118 mm Hg) in Afro-Caribbean than European women. Migrants from West Africa and the Caribbean had similar blood pressures. Body mass index was higher in Afro-Caribbean than European women, accounting for 4 mm Hg of the systolic difference. Diabetes prevalence was 16% in Afro-Caribbeans and 5% in Europeans (P < .001), accounting for 1 mm Hg of the difference in systolic pressure in men and 2 mm Hg in women. In participants not taking antihypertensive medication, mean fall in ambulatory systolic pressure between daytime and nighttime, adjusted for resting blood pressures, was 24 mm Hg in Europeans and 18 mm Hg in Afro-Caribbeans (P = .05), and percent day-night fall in systolic blood pressure adjusted for resting systolic pressure was 17% in Europeans and 12% in Afro-Caribbeans (P < .05). This difference persisted when men and women and normotensive and hypertensive individuals were examined separately. We estimate that the differences in blood pressure between Afro-Caribbeans and Europeans may be enough to account for ethnic differences in stroke mortality in women but not men. The reasons for the high prevalence of hypertension and related morbidity in this and other populations of African descent remain to be established.

Calcium channel blockers in the management of low-tension and open-angle glaucoma

Fifty-six patients with either open-angle or low-tension glaucoma who were concurrently taking calcium channel blockers were compared to similar groups not taking such medications for a mean follow-up period of 3.4 years. Serial stereoscopic optic nerve photographs and visual fields of all patients were evaluated for evidence of glaucomatous progression. In patients with low-tension glaucoma, there was a significant difference in the progression of visual field defects, with only two of 18 eyes (11%) of patients taking calcium channel blockers, compared to ten of 18 eyes (56%) of controls showing new visual field defects. Similarly, low-tension glaucoma patients taking calcium channel blocker therapy demonstrated no evidence of progressive optic nerve damage, compared to eight of 18 control eyes (44%). In contrast, patients with open-angle glaucoma taking calcium channel blockers showed no marked difference in the progression of glaucoma, compared to controls. These findings suggest that calcium channel blockers may be useful in the management of low-tension glaucoma.

Tuberculosis screening in health service employees: who needs chest X-rays?

There is uncertainty in the NHS about which individuals should be offered pre-employment screening by chest X-ray and whether this procedure is of value in the detection of tuberculosis. To provide evidence for practice, pre-employment chest X-ray and tuberculin skin test status were examined retrospectively for employees of a health district. Cases were those with an abnormal chest X-ray; referents were a sample of the remainder with a normal chest X-ray. The majority of the population had positive tuberculin skin tests and there was no difference between cases (58 positive out of 68) and referents (170 positive out of 212). Most of the X-ray abnormalities were trivial; four findings were thought significant, but would have caused no problems if undetected and none of these findings was related to tuberculosis. We conclude that in new employees in Hampstead health district, X-ray abnormalities are rare and not predicted by testing tuberculin skin reactivity; neither procedure is justified routinely as a means of screening for tuberculosis. The situation in districts with a high incidence of tuberculosis needs to be investigated.

Per rectal diazepam therapy in convulsive disorders

One hundred and twenty children with persistent convulsions (lasting > or = 10 min) were treated with per rectal diazepam (dosage: 0.2 to 0.7 mg/kg/dose). Another group of 100 age matched children with convulsions, along with those who did not respond to rectal therapy were given intravenous diazepam in a dosage of 0.2 to 0.3 mg/kg/dose. Rectal treatment was effective in 80.83% cases while intravenous diazepam was effective in 90% cases which is statistically just significant (p < 0.05). No significant difference was observed in the efficacy of two routes of administration in controlling convulsions of different clinical types and various etiological groups (p < 0.05), except for primary generalized type where intravenous route was more effective than the rectal one (p < 0.05). No significant side-effect was observed with rectal therapy. Among the 23 (19.17%) children in whom rectal therapy failed, 12 (10%) responded to intravenous diazepam while the remaining 11 (9.17%) cases were resistant to both routes of administration.

Endocrine regulation of calcium and phosphate in rat eye lens and its significance in cataract formation

Parathyroid hormone (PTH), calcitonin (CT)and calciferol (Vit. D3) operate synchronously to maintain a balance between calcium and phosphate levels in serum. An aberration of specific steps in the homeostatic process results in hypo/hyper phosphatemia. These aberrations may eventually lead to several diseased states. PTH and Vit. D3 induced hypercalcemia can, however, be significantly inhibited by calcitonin (CT). These findings have been correlated with the levels of calcium and phosphate obtained from human senile cataractous lenses of cortical and nuclear types. The comparison of the results indicate that amongst these three hormones PTH is most vulnerable in leading towards conditions for possible cataract formation in rat lens.

Topochemically related hormone structures. Synthesis of partial retro-inverso analogs of LH-RH

The syntheses of five partial retro-inverso luteinizing hormone-releasing hormone (LH-RH) analogs [g-Tyr5, m-Gly6]LH-RH, [g-Tyr5-r-Gly6, R,S-m-Leu7] LH-RH, [g-p-Glu1, m-His2]LH-RH, [g-p-Glu1-r-D-His-R,S-m-Trp3]LH-RH, and [g-Pro9-propionyl-des-Gly10]LH-RH, have been accomplished by solution methods. The choice of sequence to be reversed was based on suggested biodegradation mechanisms of LH-RH. A (gem)-diamino alkylidene residue, which was produced via Curtius rearrangement of a peptide segment, and a 2-substituted malonyl residue mark the initiating and terminating site, respectively, of the reversed sequence.