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Biomedical subjects

A Sommer

Publications and source records attributed to A Sommer.

At least 271 records · Page 15Linked to original sources
PubMed1989

Ultraviolet light exposure and risk of posterior subcapsular cataracts.

Posterior subcapsular (PSC) cataracts are a visually disabling form of cataract and account for 40% of surgical cases. Although PSC opacities may occur following intraocular inflammation, trauma, or use of steroids, the cause is often unknown. A case-control study was undertaken to investigate the role of exposure to ultraviolet light in the B range (UV-B) and other potential risk factors for the development of PSC cataracts. Surgical PSC cataract cases from a large rural ophthalmic practice on the lower eastern shore of Maryland were matched with phakic controls without PSC cataract changes from the same geographic area by age, sex, and referral pattern. All patients with PSC opacities who underwent cataract surgery in a 12-month period were chosen. One hundred sixty-eight cases and 168 controls were interviewed regarding sunlight exposure, drug use, occupational history, history of diabetes, hypertension, and other diseases. Matched-pairs analyses indicated that a history of relatively high exposure to UV-B was associated with increased risk of PSC cataracts. The association of PSC cataracts with steroid use and diabetes was reconfirmed. Subjects with blue eyes and less than high school education were also at increased risk for PSC cataracts. Smoking and hypertension were not found to be PSC cataract risk factors. These data suggest that UV-B exposure may be an important risk factor for PSC cataracts.

Adult↗
PubMed1989

Interaction of heparin with human basic fibroblast growth factor: protection of the angiogenic protein from proteolytic degradation by a glycosaminoglycan.

Fibroblast growth factors (FGF) are a family of heparin-binding angiogenic polypeptide mitogens. In the presence of heparin, recombinant human basic fibroblast growth factor (bFGF) is fully protected from tryptic digestion and partially protected from chymotryptic digestion. Complete protection of bFGF by heparin is achieved at ratios of growth factor:heparin of approximately 10 or less (w/w). The protection requires bioactive bFGF because inactivated bFGF is rapidly degraded by trypsin or chymotrypsin in the presence of heparin. The bFGF-heparin interaction forms hydrophobic complexes which become insoluble in aqueous buffers at bFGF:heparin ratios of 8 to 10 (w/w). The heparin was found to bind up to a tenfold excess of bFGF on a weight basis. bFGF in the presence of heparin is as active as bFGF alone in inducing 3H-thymidine incorporation into Swiss 3T3 fibroblast DNA.

Animals↗
PubMed1989

Cost effectiveness of current approaches to the control of retinopathy in type I diabetics.

Diabetic retinopathy is a leading cause of blindness among working age Americans. The epidemiology of diabetic eye disease has been well described in population-based studies and the effects of laser treatment have been tested in randomized controlled trials. The authors have designed a computer simulation model using the published reports of these studies to predict the medical and economic effects of applying currently accepted methods for the control of diabetic retinopathy to the population of type I diabetics. Recommendations for screening are taken from the Public Health Committee of the American Academy of Ophthalmology. Treatment recommendations and treatment efficacy are drawn from the reports of the Diabetic Retinopathy Study (DRS) and the Early Treatment Diabetic Retinopathy Study (ETDRS). Costs of screening and treatment are drawn from published Medicare reimbursement data. Over a 60-year period, the model predicts that proliferative diabetic retinopathy (PDR) requiring panretinal photocoagulation (PRP) will eventually develop in 72% of type I diabetics and macular edema will develop in 42%. If these treatments are delivered as recommended in the clinical trials, the model predicts a cost of $966 per person-year of vision saved from proliferative retinopathy and $1118 per person-year of central acuity saved from macular edema. This is only one seventh of the $6900 average cost of 1 year of Social Security Disability for those disabled by vision loss. Therefore, this model supports the use of federally funded eye care to prevent blindness in medically uninsured diabetics.

Adolescent↗
PubMed1989

Human basic fibroblast growth factor gene encodes four polypeptides: three initiate translation from non-AUG codons.

Human basic fibroblast growth factor (bFGF) is an angiogenic polypeptide mitogen present in a wide variety of mesoderm- and neuroectoderm-derived tissues. bFGF cDNA and genomic clones predict a 17.8-kDa (155-amino acid) gene product based on the presence of a single putative translational initiator ATG codon. However, a bFGF protein isolated from human placenta contains two additional amino acids NH2-terminal to the predicted initiator methionine. We report here that the human cell line SK-HEP-1 coexpresses four molecular forms (17.8, 22.5, 23.1, and 24.2 kDa) of bFGF. The 17.8-kDa bFGF protein is translationally initiated at the previously predicted methionine (AUG) codon, whereas the 22.5-, 23.1-, and 24.2-kDa proteins initiate at unusual non-AUG codons. The higher molecular weight forms are colinear NH2-terminal extensions of the 18-kDa bFGF.

Animals↗
PubMed1989

New imperatives for an old vitamin (A).

This year marks the 75th anniversary of the discovery of vitamin A by E.V. McCollum. Interest over the past 40 years has focused almost exclusively on the ocular complications of deficiency. Recent data from Indonesia, India, Thailand, Tanzania, Guatemala and elsewhere are reorienting concerns. Observational studies indicate that vitamin A--deficient children grow poorly, are more anemic, have more infections and are more likely to die than their peers, and that the magnitude of many of these consequences is directly related to the severity of the deficiency, even after adjusting for other variables. The few supplementation trials completed to date support these conclusions. Even after excluding children with frank deficiency at baseline, vitamin A-supplemented children have grown faster, developed higher hemoglobin values, and died less frequently (by 30-60%) than their nonsupplemented peers. The great surprise is not the central role vitamin A plays in each of these areas (McCollum and others recognized this long ago), but that this single nutrient can so profoundly affect children who are subject to multiple adverse influences.

Animals↗
PubMed1989

The importance of age in evaluating anthropometric indices for predicting mortality.

Weights and heights were obtained on approximately 4,000 preschool-aged children in six rural villages of West Java between 1977 and 1978. Deaths occurring in the ensuing 18 months were ascertained at three-month intervals. The abilities of relative weight for height and height for age to discriminate children at greatest risk of dying were compared. Younger children (less than or equal to two years) with low height for age (less than 95% of the reference median) were at greater risk of dying than children of the same age who were not stunted. This risk declined with increasing age, and among children aged 3-5 years, those who were stunted were at no greater risk than those of normal height for age. The mortality risk associated with mild wasting (80-90% of the reference median) also declined with increasing age. However, the risk of dying among moderately to severely wasted (less than 80% of the reference median) children increased with increasing age. These results suggest that stunting, rather than wasting, puts younger children at greater risk of death, but among older children, wasting carries a greater relative mortality risk over an 18-month period.

Age Factors↗
PubMed1989

Olsalazine versus placebo in the treatment of mild to moderate ulcerative colitis: a randomised double blind trial.

The effect of olsalazine, an analogue of sulphasalazine, consisting of two molecules 5-aminosalicylic acid linked by an azobond has been investigated for the treatment of ulcerative colitis. In a randomised double blind trial we compared 2 g olsalazine with placebo for four weeks. Of the 105 patients, with mild to moderate ulcerative colitis, entered in the trial 52 received olsalazine, and 53 placebo. Treatment had to be terminated prematurely because of untoward effects of olsalazine (mainly diarrhoea) in three patients and treatment failure--that is, increased rectal bleeding in four patients (olsalazine group: one placebo group: three). After four weeks' treatment, a statistically significant improvement in the endoscopic findings in rectum and a positive trend in the reduction of rectal mucus and blood discharge was observed in the patients treated with olsalazine. No statistically significant difference was found for other factors, including stool frequency, consistency, urge to defecate, abdominal pain, and biopsy findings. A comparison between these clinical and endoscopic parameters at study entry and those at study completion (within drug evaluation) showed significant improvement in six of 10 parameters during treatment with olsalazine and in two of 10 during placebo treatment. This difference suggests the significant effect of olsalazine. We conclude that 2 g olsalazine was tolerated as well as placebo, apart from causing diarrhoea in some patients and was slightly superior to placebo during four weeks' treatment of mild to moderate ulcerative colitis. A study with 3 or 4 g olsalazine per day may show a more definite effect.

Adolescent↗
PubMed1989

Large dose vitamin A to control vitamin A deficiency.

Vitamin A deficiency is a serious problem throughout the developing world. An estimated 25-50 million children may well suffer the physiologic consequences of vitamin A deficiency; 5 million develop xerophthalmia, of whom 250,000 to 500,000 go blind every year; and untold numbers are at increased risk of diarrhea, respiratory disease, and death. Even mild vitamin A deficiency has been associated with a 14- to 10-fold increase in mortality, and controlled field trials have demonstrated vitamin A supplementation can reduce childhood death rates by 30%-70%. Three general intervention strategies exist for improving vitamin A status of high-risk, rural, economically deprived populations. These include nutrition education leading to increased dietary intake; vitamin A fortification of centrally processed, widely consumed dietary items; and periodic administration of large doses of vitamin A. At present, the latter is far and away the most widely employed intervention activity, because of its immediate impact, and because it can be implemented through the existing (and specialized) health care infrastructure. Vitamin A is a fat-soluble vitamin stored in the liver, so that a large dose of 200,000 IU (100,000 IU for children under 1 year of age) every 6 months reduces mortality, stimulates growth, and prevents xerophthalmia and nutritional blindness. Recent data suggest more frequent administration, every 3 to 4 months, may be desirable. Side effects have been minimal, with mild nausea, vomiting, and headaches in less than 1% to 4% of recipients. Care should be taken, however, that doses above 10,000 IU not be administered to women during the first trimester of pregnancy because of potential teratogenic effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1989

Transformation by basic fibroblast growth factor requires high levels of expression: comparison with transformation by hst/K-fgf.

Basic fibroblast growth factor is a potent mitogen for a variety of cell types and has been suggested to have transforming activity. To test this hypothesis, we have introduced a human bFGF cDNA into NIH 3T3 cells either by DNA transfection or by retrovirus infection. We have compared the properties of cell lines obtained with cells prepared similarly but expressing the hst/K-fgf growth factor. While bFGF does not contain an amino terminal signal sequence and is not secreted from cells in which it is synthesized, hst/K-fgf does contain a signal sequence and is secreted from cells. Our results show that the transformed phenotype correlates directly with the level of bFGF expression, since all transformed clones expressed high levels of bFGF, while nontransformed clones expressed comparatively low levels of bFGF. In contrast, even low levels of hst/K-fgf expression resulted in a transformed phenotype. These results suggest that bFGF is an inefficient transforming protein and that this may relate to its lack of secretion.

Animals↗
PubMed1989

[The hormonal response in bulls to the administration of zeranol and rumensin].

The objective of the study was to investigate the influence of the growth stimulators Ralgro zeranol and Rumensin on changes in concentrations of certain hormones in the blood of beef bulls. In the first experiment 21 bulls were investigated which were divided into three groups. The first group was control, the second was administered the Ralgro stimulator (3X) and the third the Ralgro and Rumensin stimulators. In the second experiment there were 12 bulls. The animals in the test group were implanted Ralgro five times during the fattening period. Alternate changes, mostly insignificant, were recorded between the groups in the concentration of triiodothyronine and cyclic adenosine phosphate. Thyroxine concentrations were reduced during all investigations of the first and second experiments in the animals stimulated by the Ralgro preparation. A significant increase was recorded in the bulls at the age of 14.3 months in the second experiment (62.8 nmol.l-1, in comparison with 56.9 nmol.l-1). In both experiments an identical trend of insulin content was observed--in seven out of the total number of eight observations the animals treated with the Ralgro preparation had statistically insignificantly higher values. The largest differences were recorded at the age of 11.1 and 14.3 months in the second experiment (3.9 microIU.ml-1 and 3.6 microIU.ml-1). Significant differences were observed in testosterone concentrations in the second bulls of the test group were lower by 1.9+ nmol.l-1 and 3.4++ nmol.l-1, respectively.

Animals↗
PubMed1989

Familial occurrence of primary fibromyalgia.

Seventeen families of patients with primary fibromyalgia were studied for evidence of inherited primary fibromyalgia. Fifty parents and siblings were included in the analysis. Twenty-six (52%, mean age 33.5 years) had characteristic symptoms and findings of primary fibromyalgia. Eleven (22%, mean age 28 years) were asymptomatic but had clinical evidence of abnormal muscle consistency to palpation without tender or trigger points. One person had clinical evidence of lupus. Thirteen (26%) had no evidence of fibromyalgia or abnormal muscle consistency. The mode of inheritance was autosomal dominant. Identical twins are described who developed symptoms of primary fibromyalgia within six months of each other, as are two brothers who developed abnormal palpable muscle consistency years before acquiring the characteristic findings of the fibromyalgia syndrome. Primary fibromyalgia may be an inherited condition with a variable latent stage before clinical expression of the disease.

Adolescent↗