Search PubMed⌕ Search

Biomedical subjects

L Stevens

Publications and source records attributed to L Stevens.

At least 73 records · Page 4Linked to original sources
PubMed1997

Retinopathy and vision loss in insulin-dependent diabetes in Europe. The EURODIAB IDDM Complications Study.

PURPOSE: To assess the frequency of retinopathy and vision loss in patients with insulin-dependent diabetes mellitus and their relations to potentially modifiable risk factors. METHODS: The authors conducted a multicenter cross-sectional study of diabetic complications and their risk factors using standardized methods of assessment. The sample was comprised of 3250 insulin-dependent diabetic patients (1668 men, 1582 women) aged 15 to 60 years with mean (standard deviation) duration of diabetes of 14.7 (9.3) years from 31 European diabetes centers; 2991 of the patients were eligible for retinal photography. Visual acuity was measured using the Snellen chart. Retinopathy was evaluated by retinal photographs (two fields per eye) graded at a central facility. Glycated hemoglobin (HbA1c), cholesterol, triglyceride, fibrinogen, von Willebrand factor, and urinary albumin excretion rate were assessed at a single location. RESULTS: Corrected visual acuity was greater than or equal to 1.0 in both eyes in 69.7% of patients and less than or equal to 0.1 in the best eye in 2.3%. Factors significantly related to vision loss were age, duration of diabetes, glycated hemoglobin (HbA1c), and level of retinopathy. Mild nonproliferative retinopathy was found in 25.8% of the patients, moderate-severe nonproliferative retinopathy in 9.8% of the patients, and proliferative retinopathy in 10.6% of the patients. After adjustment for age, duration of diabetes, HbA1c, and albumin excretion rate, significant risk factors for moderate-severe nonproliferative retinopathy were blood pressure and triglyceride, and risk factors for proliferative retinopathy were triglyceride and fibrinogen. CONCLUSION: Vision loss is a common complication of patients with insulin-dependent diabetes, with diabetic retinopathy an important cause. Apart from poor glycemic control, several other potentially modifiable risk factors for retinopathy may be important, including elevated blood pressure, plasma triglyceride, and fibrinogen. In view of the possible barriers to the full implementation of strict glycemic control in this type of diabetes, additional strategies for the prevention and slowing of progression of retinopathy should be investigated, such as blood pressure and lipid lowering therapies.

Adolescent↗
PubMed1997

Contractile properties and myosin heavy chain composition of newborn rat soleus muscles at different stages of postnatal development.

This study was undertaken to correlate some of the functional characteristics with the myofibrillar composition in myosin heavy chain isoforms on newborn and adult rat soleus muscles. The following postnatal ages were chosen in order to determine the role of innervation in the establishment of the mature muscle phenotype: before (postnatal day 6), when (postnatal day 12), and after (days 17 and 23) the monosynaptic innervation appeared. The steady state of definitive innervation was controlled on adult muscles (i.e. approximately 13 weeks). Muscle maturation was followed by ATPase staining and fibre diversity was observed at postnatal day 12. The functional properties of skinned bundles isolated from newborn rats were determined by Calcium/Strontium activation characteristics (Tension/pCa and pSr relationships). From postnatal days 6 to 17, the Soleus bundles exhibited Calcium/Strontium activation characteristics intermediate between slow and fast fibre populations previously described in muscles. At day 23, the Calcium/Strontium activation characteristics of the soleus were closer to those of a slow type. Moreover, we observed a decrease in Ca affinity concomitant with the installation of the monosynaptic innervation, and an increase of the slow type I during postnatal development. Finally, this work reported a greater correlation between the Calcium/Strontium activation parameters and the myosin heavy chain isoform composition at the postnatal days when the mature monosynaptic innervation pattern occurred.

Animals↗
PubMed1997

The Hampshire Depression Project: development and piloting of clinical practice guidelines and education about depression in primary health care.

This paper describes the development and piloting of a comprehensive educational programme about recognition and management of depressive illness in primary care. Full evaluation of the effectiveness of the programme is currently underway in a randomized controlled trial, the Hampshire Depression Project (HDP), involving 56 general practices. The programme consists of clinical practice guidelines, practice-based seminars and follow-up sessions. Each part of the programme has been designed to be flexible, clinically oriented and relevant to all members of the multidisciplinary primary care team. The pilot study established the need for a systematic approach to the access of practices and practice teams, and the organization and process of the seminars. Application of this approach was associated with excellent attendance in the main programme.

Depression↗
PubMed1997

Comparative study of ovomucoid isolated from Muscovy duck (Cairina moschata), domestic goose (Anser anser) and domestic duck (Anas platyrhynchos).

1. Ovomucoids were purified from Muscovy duck, domestic duck and domestic goose. 2. Peptide maps of cyanogen bromide-cleaved ovomucoids from Muscovy duck and domestic duck were very similar to one another, but differed from that of goose. 3. Muscovy duck ovomucoid showed the same protease inhibitory pattern as ovomucoid from domestic duck, inhibiting trypsin in the molar ratio of 1:2 and chymotrypsin 1:1. 4. Inhibitory complexes could be detected between chymotrypsin and ovomucoid from both Muscovy and domestic duck, but not from goose, by using non-denaturing gels. 5. No complexes could be detected between DFP-inactivated chymotrypsin and any of the ovomucoids. 6. The results show that of ovomucoid from Muscovy duck more closely resembles that from domestic duck than goose.

Animals↗
PubMed1997

Which features of smoking determine mortality risk in former cigarette smokers with diabetes? The World Health Organization Multinational Study Group.

OBJECTIVE: The effects of quitting smoking on mortality risk in individuals with diabetes is unknown and may differ from the benefits observed in the general population. We therefore determined the mortality risks in ex-smokers with diabetes, compared with subjects who have never smoked, by the number of years since quitting, the number of cigarettes smoked, and the number of years of smoking. RESEARCH DESIGN AND METHODS: An international cohort study of 4,427 individuals with diabetes was studied. Baseline examinations were performed in 1975-1977 when smoking habits were determined by questionnaire. Mortality follow-up continued until 1988. RESULTS: All-cause mortality risks were higher for recent quitters (1-9 years; relative risk [RR], 1.53 [95% CI 1.19-1.97]; P = 0.001) than for those who quit earlier (> or = 10 years; RR, 1.25 [95% CI 1.03-1.52]; P = 0.02), compared with subjects who have never smoked. These risks were highest in those who had smoked the longest (> or = 30 years: RR, 1.66 [95% CI 1.22-2.26]; P = 0.001; vs. 1-9 years: RR, 1.17 [95% CI 0.85-1.60]; P = 0.3). Risks were also highest in those who had smoked the most and least number of cigarettes. Adjustment for key confounders, which included a previous history of heart disease, proteinuria, and blood pressure, did not materially affect these relationships. CONCLUSIONS: Quitting smoking does reduce mortality risk in ex-smokers with diabetes, but risks remain high several years after quitting and are highly dependent on the duration of smoking. Thus, individuals with diabetes who smoke should be encouraged to quit as soon as possible in the course of disease.

Adult↗
PubMed1997

Mouse RT6 locus 1 and rat RT6.2 are NAD+. Arginine ADP-ribosyltransferases with auto-ADP-ribosylation activity.

We report that rat RT6.2 and recombinant mouse Rt6 locus 1 proteins possess auto-ADP-ribosyltransferase activity and that Rt6, but not RT6, catalyzes the ADP-ribosylation of exogenous histones. Based on NH2OH sensitivity, it appeared that the ADP-ribose was attached to arginine residues on proteins. We also observed that the NAD+ concentration in culture medium correlates inversely with the proliferation of rat RT6+ T cells. The data suggest that lymphocyte surface ADP-ribosyltransferases could be involved in signaling and immunoregulatory processes.

ADP Ribose Transferases↗
PubMed1997

Sex chromosomes and sex determining mechanisms in birds.

The sex chromosomes in birds are designated Z and W, and the male is the homomorphic sex (ZZ) and the female heteromorphic (ZW). In most avian species the Z chromosome is a large chromosome, usually the fourth or fifth largest, and it contains almost all the known sex-linked genes. The W chromosome is generally a much smaller microchromosome, containing a high proportion of repeat sequence DNA. Recently a gene encoding a protein involved in transcriptional activation of chromatin has been detected on the W chromosome. The weight of evidence suggests that sex determination in birds is by a genic balance mechanism, in which the ratio of autosomes to Z chromosomes is the crucial factor. DNA sequences homologous to the testis determining factor in humans have been detected in both male and female birds, but it is not clear that they have a sex-related function in birds. A number of different practical methods have been developed to distinguish the sex of birds, based on sex-linked genes, the amount of DNA per cell and using DNA probes for sex-linked sequences.

Animals↗
PubMed1996

Some repair-deficient mutants of Dictyostelium discoideum display enhanced susceptibilities to bleomycin.

Dictyostelium discoideum, a soil eukaryote, is highly resistant to DNA-damaging agents; repair mutants are more susceptible. Susceptibility to bleomycin, produced by Streptomyces verticillus, is greater for mutants which are susceptible to other agents than for resistant strains. The high potential for DNA repair may result from the need to cope with chemicals produced by other soil microorganisms.

Animals↗
PubMed1996

Role of nonspecific cross-reacting antigen, a CD66 cluster antigen, in activation of human granulocytes.

Nonspecific cross-reacting antigen (NCA) is the name of a family of highly glycosylated bacterial-binding receptors found on human granulocytes and other tissues. These glycoproteins are members of the immunoglobulin supergene family and are related structurally to carcinoembryonic antigen. In this study, we demonstrate that ligation of granulocyte NCA results in the activation of the cells, as measured by degranulation and the flux of intracellular calcium. These studies further the proposition that NCA has a function in the immune response of granulocytes against bacterial infections.

Antibodies, Monoclonal↗
PubMed1996

Excess mortality and its relation to hypertension and proteinuria in diabetic patients. The world health organization multinational study of vascular disease in diabetes.

OBJECTIVE: To determine the extent that mortality in IDDM and NIDDM patients is in excess of that of the general population and examine its relation to hypertension and proteinuria in diabetic patients. RESEARCH DESIGN AND METHODS: A stratified random sample of 4,714 diabetic patients aged 35-55 years participating in the World Health Organization Multinational Study of Vascular Disease in Diabetes has been followed up from 1975 to 1987. Excess mortality, compared with the background population, was assessed in terms of standardized mortality ratios (SMRs) for each of the 10 international cohorts. The relationship between excess mortality and proteinuria/hypertension was examined by diabetes type and sex. RESULTS: SMRs were in general higher in patients with IDDM (ranging from 188 to 686 for men and from 336 to 790 for women) than with NIDDM (from 138 to 370 for men and from 126 to 435 for women). For both diabetes types and in both sexes, SMRs decreased with increasing age and increased with increasing diabetes duration. Patients with both hypertension and proteinuria experienced a strikingly high mortality risk: 11-fold for men with IDDM and 18-fold for women with IDDM and 5-fold for men with NIDDM and 8-fold for women with NIDDM. Even in the absence of proteinuria and hypertension, SMRs were significantly increased in both IDDM (284 men and 360 women) and NIDDM (192 men and 236 women) patients. CONCLUSIONS: Considerable international differences were found not only in mortality rates for the two types of diabetes but also in the extent of excess mortality among centers. IDDM patients had a high excess mortality in comparison with the general population. The significant excess mortality was demonstrated even in patients without proteinuria and without hypertension for both sexes and diabetes types.

Adult↗
PubMed1996

Egg proteins: what are their functions?

The principal functions so far attributed to egg proteins are: (i) provision of nutrient for the developing embryo; (ii) protection of the egg from microbial attack; and (iii) transport of nutrients into the developing embryo. All the proteins contribute to the nutrient role in the form of the amino acid residues they contain. Some also contribute to the phosphate reserves. Protection is provided by a variety of means, including the physical barrier of albumen with its high viscosity, and the chemical barriers in the form of protease inhibitors, nutrient sequesters, a lytic enzyme, and antibodies. Various proteins are involved in nutrient uptake, either by acting as carriers or in the form of membrane receptors.

Amino Acids↗