Search PubMed⌕ Search

Biomedical subjects

A Sommer

Publications and source records attributed to A Sommer.

At least 199 records · Page 11Linked to original sources
PubMed1993

[Determining energy density distribution in laser irradiation fields, generated by the LILAB system].

Laser energy densities of less than 1 J/cm2 had no apparent effect on human tissues, while energy densities of more than 4 J/cm2 resulted in tissue damage. For non-punctiform laser applications, therefore, a laser beam distribution system that provides a homogeneous energy density distribution is of advantage, since such a system permits safe application of the laser in the effective therapeutic range. Conventional laser scanners for medical use have been reported to produce grossly inhomogeneous energy density distributions. The new LILAB system, which is a very fast laser beam distribution system, readily generates application fields of different configuration with high homogeneous energy density distribution. The article presents an example of a randomly selected application field, in which the energy densities at the edges and at the centre are compared.

Animals↗
PubMed1993

Long-term follow-up after eradication of Helicobacter pylori with a combination of omeprazole and amoxycillin.

Early studies have suggested that omeprazole may facilitate the eradication of Helicobacter pylori. Sixty patients with duodenal ulcer and H. pylori colonization were randomly assigned to receive either omeprazole monotherapy (n = 30) or combination therapy with omeprazole and amoxycillin (n = 30) for a total duration of 6 weeks. Four patients receiving monotherapy and three receiving combination therapy had to be withdrawn from the study. All (100%) duodenal ulcers healed in patients receiving combination therapy, and 25 out of 26 (96%) healed in the group receiving monotherapy. H. pylori was eradicated in 22 out of 27 (82%) patients receiving combination therapy; only two ulcer relapses (9%) occurred within 18 months in these 22 patients. Of the five patients who remained H. pylori-positive after combination therapy, two relapsed during the 18-month follow-up. In the monotherapy group, all patients remained H. pylori-positive after treatment, and duodenal ulcer relapsed in 16 out of 25 (64%) patients within the median follow-up of 18 months. Adverse events were not reported in the group treated with combination therapy; one patient receiving monotherapy reported severe headache. These results lend further support to existing data that H. pylori eradication prevents duodenal ulcer relapse and show that combination therapy with omeprazole and amoxycillin is effective and well tolerated.

Adolescent↗
PubMed1993

Properties of glycosylated and non-glycosylated human recombinant IGF binding protein-3 (IGFBP-3).

The interaction of insulin-like growth factor-I with glycosylated and nonglycosylated human recombinant IGFBP-3 was studied by competition binding and by realtime biospecific interaction analysis (BIA). No significant difference was found in the affinity of the two forms of recombinant IGFBP-3 for IGF-I. Combining the results from the two different methods of binding analysis, a dissociation constant of 50 +/- 14 pM was determined. This value compares favorably to that reported for IGF-I binding to natural human plasma-derived IGFBP-3. Subcutaneous injection into rats of IGF-I either bound to glycosylated or nonglycosylated IGFBP-3 yielded an area under the curve (AUC) that was essentially the same for either form of IGFBP-3 and was twice as large as the AUC obtained after injection of IGF-I in the free form. Circulating IGF-I peak levels were reached in less than 1 h post-injection for free IGF-I, 4 and 8 h post-injection for the nonglycosylated and glycosylated IGF-I/IGFBP-3 complexes respectively. Neutral gel filtration of rat serum samples 4 and 8 h post-injection revealed that the IGF-I delivered bound to the nonglycosylated IGFBP-3 circulated as a 40-50 kDa complex at the 4 h time point and as a 130-140 kD complex at the 8 h time point. IGF-I delivered as a complex with glycosylated IGFBP-3 was found to circulate as a 140 kD complex at 4 and 8 h post-injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Automated suprathreshold screening for glaucoma: the Baltimore Eye Survey.

PURPOSE: To evaluate automated suprathreshold perimetric screening for glaucoma in a population-based survey of ocular disorders in east Baltimore, Maryland. METHODS: A population-based sample of persons > or = 40 years of age residing in 16 clusters was selected for an ocular screening examination that included automated suprathreshold testing with the Full Field 120 program of the Humphrey Field Analyzer. Subjects who failed the test underwent manual testing to confirm the defect. Subjects were referred for definitive examination by an ophthalmologist if they had an abnormal field, visual acuity worse than 20/30, intraocular pressure > 21 mm Hg, optic disc damage, a history of glaucoma, or shallow angles. The sensitivity and specificity of the automated visual field testing for identifying glaucoma was estimated and compared with other methods to screen for glaucoma. RESULTS: Of 5,341 subjects > or = 40 years of age who underwent a screening eye examination at neighborhood centers, 4,735 (89%) completed the automated field test. The median test time was 7.25 minutes per eye. Screening test results were abnormal in one or both eyes in 1,234 (26%) of the subjects. Kinetic perimetry was performed on 95% of these subjects, and defects were confirmed for 448 (36%) of them. Hence, 9.5% of the 4,735 subjects who completed the automated test were referred for definitive examination because the defect on automated perimetry was confirmed on manual testing. For a specificity of 90%, the sensitivity of the screening visual field test to detect glaucoma was 52% for 17 or more relative or absolute defects, higher than that of intraocular pressure at 39% for a cut-off of 20.5 mm Hg, vertical cup-to-disc ratio at 45% for a cut-off of 0.53, narrowest remaining rim width at 42% for a cut-off of 0.16, and was comparable to a combination of these and other nonfield parameters. CONCLUSION: Suprathreshold testing performed better than nonperimetry-based screening tests for glaucoma. However, a number of logistical weaknesses of this visual field screening method were identified.

Adult↗
PubMed1993

[Biochemical indicators of nitrogen and energy metabolism in the plasma and blood of beef bulls during the grazing season].

Concentrations of total proteins, urea, total lipids in the blood plasma and glucose concentrations in the blood of beef bullocks were followed after their transition from winter feed rations to pasture, and in the subsequent grazing cycles within two years. Blood was taken by punctures from the vena jugularis from the same six bullocks all the time. In the 1st year of observation, blood sampling took place a week before the bullocks were moved to pasture, in the 2nd year of observation blood was taken twice in weekly intervals before pasture. During grazing, biological material was sampled in weekly intervals between 1st and 5th week (May--cycle I, June--cycle II), then in the tenth week (July--cycle III) and in the 14 week (August--pasture cycle IV). The concentrations of total proteins in the blood plasma of beef bullocks (Fig. 1) insignificantly increased after transition from indoor housing to pasture, this increase continued in the second year of observation for two weeks after transition to pasture, and in the first year of observation for four weeks with a break in the 2nd week. In the subsequent period, the concentrations of total proteins decreased to the values approaching the starting values. The concentrations of plasma urea in beef bullocks (Fig. 2) significantly increased in both years of observation after transition from stable fattening to pasture (p < 0.01 and p < 0.05, resp.). In the second week after transition to pasture, further highly significant increase in the concentrations of plasma urea was observed in both years of observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1992

Organization of phosphatidylcholine and sphingomyelin in the surface monolayer of low density lipoprotein and lipoprotein(a) as determined by time-resolved fluorometry.

Fluorescent analogs of phosphatidylcholine (PC) and sphingomyelin (SM) labeled with diphenylhexatrienylpropionic acid (DPH) were prepared and incorporated into the surface layer of human low density lipoprotein (LDL) and lipoprotein(a) (Lp(a)). Fluorescence anisotropy measurements of DPH-PC and DPH-SM in both lipoprotein classes were carried out at different temperatures ranging from 20 to 37 degrees C. DPH-PC as well as DPH-SM were shown to reside in more rigid domains in Lp(a) than in LDL according to higher anisotropy values in Lp(a). In both LDL and Lp(a), DPH-PC experienced a more rigid environment than DPH-SM, suggesting different environments of PC and SM in the surface shell of the lipoproteins. Fluorescence lifetimes of the labeled lipoproteins were determined by phase and modulation fluorometry. We found bimodal Lorentzian distributions for the decay times of DPH-PC and DPH-SM in LDL and Lp(a). Lifetime distribution centers for labeled lipids were very similar except for DPH-PC in Lp(a) which was shifted to longer lifetimes, suggesting a less polar environment of PC in Lp(a) than in LDL. The distributional width of DPH-PC in Lp(a) was broader than in LDL. Accordingly, phosphatidylcholine must be localized in a more homogeneous environment in LDL as compared with Lp(a). On the other hand, no difference in distributional widths was observed for DPH-SM in both lipoproteins, showing that SM organization in Lp(a) is unaffected by apo(a). From the obtained fluorescence data we propose that apoproteins discriminate between the choline phospholipids and preferentially associate with phosphatidylcholine. This effect is enhanced in Lp(a) due to the presence of apolipoprotein(a).

Fluorescence Polarization↗
PubMed1992

Autosomal dominant inheritance of tetramelic monodactyly.

We report on tetramelic monodactyly with autosomal dominant inheritance. The propositus and all affected relatives had only digital malformations as determined by physical examination or history. Since it could not be determined that the involved digits of the propositus or relatives were fifth fingers and toes, we conclude this to be the first report of this type of hand and foot malformation with autosomal dominant inheritance.

Adult↗
PubMed1992

National outcomes of cataract extraction. Increased risk of retinal complications associated with Nd:YAG laser capsulotomy. The Cataract Patient Outcomes Research Team.

PURPOSE: The authors studied 57,103 randomly selected Medicare beneficiaries who underwent extracapsular cataract extraction in 1986 or 1987 to determine the possible association between performance of neodymium (Nd):YAG laser capsulotomy and the risk of subsequent retinal break or detachment. METHODS: Cases of cataract surgery were identified from Medicare claims submitted in 1986 and 1987 and were followed through the end of 1988. Episodes of cataract surgery, posterior capsulotomy, and retinal complications were ascertained based on procedure and diagnosis codes listed in physician bills and hospital discharge records. Lifetable and Cox's proportional hazards models were used to analyze the risk of retinal detachment or break in patients undergoing and not undergoing capsulotomy during the period of observation. RESULTS: Of the 57,103 persons identified as having undergone extracapsular cataract extraction in 1986 or 1987, 13,709 subsequently underwent Nd:YAG laser capsulotomy between 1986 and 1988. A total of 337 persons had aphakic or pseudophakic retinal detachments between 1986 and 1988 and an additional 194 underwent repair of a retinal break. Proportional hazards modeling shows a 3.9-fold increase in the risk of retinal break or detachment among those who underwent capsulotomy (95% confidence interval: 2.89 to 5.25). Younger patient age, male sex, and white race also were associated with increased risk of retinal complications after extracapsular cataract extraction. CONCLUSION: The authors conclude that there is a statistically significant increase in the risk of retinal detachment or break in those patients who undergo capsulotomy after cataract extraction. Therefore, capsulotomy should be deferred until the patient's impairment caused by capsular opacification warrants the increased risk of retinal complications associated with performance of capsulotomy.

Aged↗
PubMed1992

An evaluation of optic disc and nerve fiber layer examinations in monitoring progression of early glaucoma damage.

From annual examinations of 813 ocular hypertensive eyes, the authors compared optic disc and nerve fiber layer photographs in 2 age-matched subgroups: 37 eyes that converted to abnormal visual field tests at the end of a 5-year period and 37 control eyes that retained normal field tests. Disc change was detected in only 7 of 37 (19%) converters to field loss and in 1 of 37 (3%) controls. Progressive nerve fiber layer atrophy was observed in 18 of 37 (49%) converters and in 3 of 37 (8%) controls. Serial nerve fiber layer examination was more sensitive than color disc evaluation in the detection of progressive glaucoma damage at this early stage of glaucoma. The evaluation of cup-to-disc ratio or of the nerve fiber layer appearance in the initial photograph taken 5 years before field loss were equally predictive of future field damage. The position of nerve fiber layer defects was highly correlated with the location of subsequent visual field loss.

Aged↗
PubMed1992

Maternal but not paternal transmission of 15q11-13-linked nondeletion Angelman syndrome leads to phenotypic expression.

Angelman syndrome (AS) may result from either maternally inherited deletions of chromosome 15q11-13 or from paternal uniparental disomy for chromosome 15. This is in contrast to Prader-Willi syndrome (PWS), which is caused by either paternal deletion of this region or maternal disomy for chromosome 15. However, 40% of AS patients inherit an apparently intact copy of chromosome 15 from each parent. We now describe a family in which three sisters have given birth to four AS offspring who have no evidence of deletion or paternal disomy. We show that AS in this family is caused by a mutation in 15q11-13 that results in AS when transmitted from mother to child, but no phenotype when transmitted paternally. These results suggest that the loci responsible for AS and PWS, although closely linked, are distinct.

Angelman Syndrome↗
PubMed1992

[The nitrogen metabolism in the large intestine of ruminants. 8. Metabolism of intracecally infused 15N-urea with a supplement of pectin in heifers].

Three heifers with live weights of 255, 261 and 300 kg were supplied with ileo-caecal re-entrant cannulas, jugular vena catheters and bladder catheters. The ration consisted of 4 kg maize silage and 4 kg wheat straw pellets. In a previous period 50% of the digesta flow was collected over 12 h/d on 5 consecutive days and stored in a deep-freeze. During the main period the re-entrant cannulas were disrupted and the flowing digesta was quantitatively collected. Precollected digesta and pectin were infused into the distal part of cannula hourly for about 30 hours. During the first 24 hours the digesta was also supplemented with 15N-labelled urea. The amount of pectin corresponded to about 10% of digesta dry mater. An analysis of urine, faeces, digesta and blood plasma were carried out. The application of pectin increased the 15N-incorporation in the bacterial protein of faeces from 4.7% (without supplementation in an earlier experiment) to 10.5% of the introduced 15N. The ammonia-fraction of faeces was markedly higher than the bacterial fraction. The 15N-utilization of urea by the microbes of large intestine was lower in the actual trial evident than with supplementation of starch in the anterior experiment. During the pectin administration the amount of urine increased in comparison with earlier experiments and according to the literature to about the 4.5 fold. The amount of passage of 15N at the ileum cannula (recycled 15N) was 3.8% of the 15N intake. It is the same amount as in experiments in which starch was applied.

Animal Feed↗
PubMed1992

Xerophthalmia and growth in preschool Indonesian children.

Approximately 4000 preschool children in West Java, Indonesia, were examined for xerophthalmia and weighed and measured at 3-mo intervals from March 1977 to December 1978. Children recovering from xerophthalmia over a 3-mo interval gained an average of 124 g (95% CI 42-206) more over 3 mo than normal children. Their height gain was similar to normal children's. Children who developed xerophthalmia during a 3-mo period gained 199 g (95% CI 114-313) less and grew 0.28 cm (95% CI 0.12, 0.44) less than their normal peers. Children with chronic xerophthalmia gained 120 g (95% CI 49-191) less and grew 0.21 cm (95% CI 0.05-0.37) less than normal children. These data suggest that linear and ponderal growth is adversely affected by chronic and incident xerophthalmia, but that catch-up ponderal growth is experienced by children recovering from xerophthalmia.

Body Height↗
PubMed1992

Depressed immune response to tetanus in children with vitamin A deficiency.

A randomized, double-masked, placebo-controlled clinical trial was conducted with 236 preschool children, age 3-6 y, in Indonesia to assess immune status in mild vitamin A deficiency. The immune response to tetanus immunization was used as a measure of immune competence. Clinically normal children (n = 118) and children with mild xerophthalmia (n = 118) were randomly assigned to receive oral vitamin A (60,000 micrograms retinol equivalent) or placebo treatment for a total of four study groups. Two weeks after treatment, children were immunized with diphtheria-pertussis-tetanus vaccine. The immunoglobulin G (IgG) responses to tetanus at baseline and 3 wk following immunization were measured by ELISA. After adjusting for previous tetanus immunization, clinically normal and xerophthalmic children receiving vitamin A had a significantly greater IgG response to tetanus than clinically normal and xerophthalmic children receiving placebo (P less than 0.05). These results suggest that children with mild vitamin A deficiency have a relative immune depression compared with children who have been supplemented to normal vitamin A levels.

Antibody Formation↗