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Biomedical subjects

A Sommer

Publications and source records attributed to A Sommer.

At least 127 records · Page 7Linked to original sources
PubMed1995

The role of universal distribution of vitamin A capsules in combatting vitamin A deficiency in Bangladesh.

Vitamin A deficiency is a major public health problem among preschool-aged children in many developing countries. In Bangladesh, a national nutritional surveillance system was initiated in 1990 to monitor 1) the occurrence of vitamin A deficiency by history of night blindness and 2) the routine coverage of national twice-yearly prophylactic vitamin A capsule (VAC) distribution. This study comprised data collected from June 1990 to August 1994. The VAC distribution had a mean coverage rate of 48.7% (95% confidence interval (CI) 48.4-49.0) in the rural areas; the coverage rate in the urban slums was 93.7% (95% CI 93.4-94.0). In the rural areas, the mean prevalence of night blindness was 0.86% (95% CI 0.81-0.91) and the bimonthly prevalence of night blindness ranged from 0.50% (95% CI 0.32-0.77) to 1.48% (95% CI 1.19-1.85), while in the urban slums the mean prevalence was 0.22% (95% CI 0.18-0.28) and the bimonthly prevalence ranged from zero to 0.62% (95% CI 0.27-1.37). The efficiency of VAC distribution was 27% (95% CI 17.6-35.3) in the rural areas and 77.8% (95% CI 61.8-87.1) in the urban slums. After adjustment for multiple potentially confounding factors, VAC receipt by individual children reduced the risk of night blindness in both rural and urban areas (rural areas: odds ratio (OR) = 0.74, 95% CI 0.63-0.87; urban slums: OR = 0.39, 95% CI 0.19-0.82). Breastfeeding was a protective factor for night blindness in both rural (OR = 0.53, 95% CI 0.42-0.67) and urban (OR = 0.32, 95% CI 0.15-0.66) areas. Night blindness was inversely related to the level of routinely attained coverage, and the degree of protection was associated with the time interval between the moment of VAC receipt and the moment of data collection. Although the prevalence of vitamin A deficiency in Bangladesh has been considerably lower in the 1990s than it was in the 1980s, it is still prevalent at all socioeconomic levels. Supplementation with high-dose VACs is an effective strategy for reducing night blindness, but the efficiency of the program will improve when coverage in the rural areas increases.

Bangladesh↗
PubMed1995

Reduced seroconversion to measles in infants given vitamin A with measles vaccination.

Administration of 100,000 IU vitamin A at the time of measles immunisation is currently recommended for infants in developing countries. However, the safety and value of giving vitamin A, a potent immune enhancer, with live measles virus vaccines are unknown. We conducted a randomised, double-blind, placebo-controlled clinical trial in Indonesia to evaluate the effect of simultaneous vitamin A supplementation on the immune response to measles immunisation at six months of age. 336 infants received either vitamin A (100,000 IU) or placebo when immunised with standard-titre Schwarz measles vaccine. 82% of infants seroconverted to measles. In a multiple logistic regression model adjusting for maternal antibody titres, vitamin A supplementation was associated with a lower likelihood of seroconversion to measles (odds ratio 0.40, 95% CI 0.19-0.88), and girls were less likely to seroconvert than boys (0.34, 0.15-0.76). Immunisation with standard-titre Schwarz vaccine at six months of age in this study population is characterised by high seroconversion rates. However, simultaneous high-dose vitamin A may interfere with seroconversion to live measles vaccine in infants with maternal antibody.

Antibodies, Viral↗
PubMed1995

Spectrum of X-linked hydrocephalus (HSAS), MASA syndrome, and complicated spastic paraplegia (SPG1): Clinical review with six additional families.

X-linked hydrocephalus (HSAS) (MIM *307000), MASA syndrome (MIM *303350), and complicated spastic paraplegia (SPG1) (MIM *312900) are closely related. Soon after delineation, SPG1 was incorporated into the spectrum of MASA syndrome. HSAS and MASA syndrome show great clinical overlap; DNA linkage analysis places the loci at Xq28. In an increasing number of families with MASA syndrome or HSAS, mutations in L1CAM, a gene located at Xq28, have been reported. In order to further delineate the clinical spectrum, we studied 6 families with male patients presenting with MASA syndrome, HSAS, or a mixed phenotype. We summarized data from previous reports and compared them with our data. Clinical variability appears to be great, even within families. Problems in genetic counseling and prenatal diagnosis, the possible overlap with X-linked corpus callosum agenesis and FG syndrome, and the different forms of X-linked complicated spastic paraplegia are discussed. Since adducted thumbs and spastic paraplegia are found in 90% of the patients, the condition may be present in males with nonspecific mental retardation. We propose to abandon the designation MASA syndrome and use the term HSAS/MASA spectrum, incorporating SPG1.

Agenesis of Corpus Callosum↗
PubMed1995

The prevalence of blindness and visual impairment among nursing home residents in Baltimore.

BACKGROUND: Although the prevalence of blindness and visual impairment increases with age, most surveys of ocular disease do not include nursing home residents. METHODS: We conducted a population-based prevalence survey of persons 40 years of age or older residing in nursing homes in the Baltimore area. Of 738 eligible subjects in 30 nursing homes, 499 (67.6 percent) participated in the study. They had their eyes examined and their visual acuity tested and were interviewed in detail. The nonparticipants were more likely to be older, to be white, and to have lower scores on the Mini-Mental State Examination. RESULTS: The prevalence of bilateral blindness (visual acuity < or = 20/200) was 17.0 percent. The prevalence of visual impairment (< 20/40 but > 20/200) was 18.8 percent. The frequency of blindness increased from 15.2 percent among those under 60 years of age to 28.6 percent among those 90 or older. The age-adjusted prevalence of blindness was 50 percent higher among blacks than among whites (P < 0.01). As compared with the noninstitutionalized population from the same communities, the rate of blindness among nursing home residents was 13.1 times higher for blacks and 15.6 times higher for whites. Cataract was the leading cause of blindness, followed by corneal opacity, macular degeneration, and glaucoma. We judged that 20 percent of the functional blindness and 37 percent of the visual impairment could be remedied by adequate refractive correction. CONCLUSIONS: Blindness and visual impairment are highly prevalent among nursing home residents. Much of this loss of vision could be treated or prevented with appropriate ophthalmologic care.

Adult↗
PubMed1995

Hypertension, perfusion pressure, and primary open-angle glaucoma. A population-based assessment.

OBJECTIVE: To evaluate the association of vascular factors with primary open-angle glaucoma (POAG). DESIGN: A population-based prevalence survey of ocular disease among black and white residents. SETTING: Communities of east Baltimore, Md. PARTICIPANTS: A stratified cluster sample of 5308 residents 40 years of age or older. MAIN OUTCOME MEASURES: Primary open-angle glaucoma as defined by demonstrable glaucomatous optic nerve damage based on visual fields and/or optic disc findings. Intraocular pressure level was not a criterion for diagnosis. RESULTS: Systolic and diastolic blood pressure showed modest, positive association with POAG. The effect of blood pressure on POAG was modified by age, with a stronger association among older subjects. Lower perfusion pressure (blood pressure-intraocular pressure) was strongly associated with an increased prevalence of POAG, with a sixfold excess for those in the lowest category of perfusion pressure. CONCLUSION: These results suggest that POAG is associated with an alteration in factors related to ocular blood flow and a breakdown of autoregulation.

Adult↗
PubMed1995

Neural rim area declines with increased intraocular pressure in urban Americans.

OBJECTIVE: To determine intraocular pressure (IOP)-related differences in the neural rim area among urban Americans without known optic nerve disease. DESIGN: Population-based prevalence study conducted in 16 cluster areas in East Baltimore, Md. PARTICIPANTS: A population-based sample of 1521 black and 1851 white individuals aged 40 years and older without evidence of optic nerve disease. MAIN OUTCOME MEASURE: Intraocular pressure-related differences in neural rim area, neural rim area-to-disc area ratio, and cup-to-disc ratio. RESULTS: We analyzed optic disc photographs using the Imagenet system (Topcon Instrument Corp of America, Paramus, NJ). After adjusting for age and disc area, white Americans had a 6% decrease in neural rim area for every 10-mm Hg increase in IOP (P = .0001). In black Americans, there was a quadratic relationship between neural rim area and IOP, with little decline with IOP up to approximately 17 mm Hg, after which neural rim area declined significantly with higher IOP (P = .001). Similarly, the neural rim area-to-disc area ratio decreased and the vertical cup-to-disc ratio increased with increasing IOP in both black and white Americans. CONCLUSIONS: The higher the level of IOP, the smaller was the amount of neural rim tissue in the optic disc for both black and white Americans. However, the relationship between IOP and neural rim area was different in whites and blacks.

Adult↗
PubMed1995

Treatment of ovariectomized rats with the complex of rhIGF-I/IGFBP-3 increases cortical and cancellous bone mass and improves structure in the femoral neck.

Sixteen-week-old Sprague-Dawley rats were ovariectomized (Ovx) or sham-operated and housed for 8 weeks to develop osteopenia prior to systemic administration of rhIGF-I (0.9 and 2.6 mg/kg) alone or the rhIGF-I/IGFBP-3 (0.9, 2.6 and 7.5 mg/kg) complex. After 8 weeks of treatment, proximal femurs were fixed, embedded, and cut through the midneck region. Structural and dynamic histomorphometric analyses were performed using standard techniques. Ovx increased endocortical resorption and modeling-dependent periosteal formation which resulted in decreased cortical bone area. Despite increased bone formation, trabecular number, thickness, and area were all reduced due to increased resorption. Structural changes following Ovx included fewer struts and nodes, a higher percentage of the simpler strut forms, and reduced endocortico-trabecular connectivity. Eight weeks of treatment with rhIGF-I or rhIGF-I/IGFBP-3 promoted periosteal and endocortical bone formation and reduced the endocortical resorption induced by Ovx. Both rhIGF-I formulations stimulated bone formation on existing trabecular surfaces which increased trabecular thickness and area but not trabecular number. These treatments prevented further deterioration of the trabecular network caused by Ovx and preserved endocortico-trabecular connectivity. In summary, changes in the femoral neck following Ovx appear to be similar in rats and humans. The highest dose of rhIGF-I/IGFBP-3 used in this study showed the best results in promoting cortical and cancellous bone formation, and appears to be promising therapy for human osteopenias.

Animals↗
PubMed1995

Double-blind trial of omeprazole and amoxicillin to cure Helicobacter pylori infection in patients with duodenal ulcers.

BACKGROUND/AIMS: Anti-Helicobacter pylori treatment with combinations of omeprazole and amoxicillin is a promising treatment option. The aim of this study was to investigate whether a daily omeprazole dose of 120 mg combined with amoxicillin would cure H. pylori infection at a rate comparable with that achieved with "triple therapy." METHODS: In a double-blind, randomized, controlled, and multicenter trial in Germany, 270 patients with an H. pylori-associated duodenal ulcer were treated with 40 mg omeprazole three times a day and 750 mg amoxicillin three times a day for the first 14 days (n = 139) followed by 20 mg omeprazole once daily until day 42 or with omeprazole plus 750 mg amoxicillin placebo three times a day for the same time period (n = 131). RESULTS: Cure rates of H. pylori infection were 91% in the omeprazole plus amoxicillin group, 0% in the omeprazole plus placebo group, and 89% and 0%, respectively, performing an intention-to-treat analysis. Cure of H. pylori infection in patients pretreated with omeprazole was only 58% compared with 95% in patients who were not. The cumulative 12-month relapse rates were 11.3% and 44% in the treatment groups and 1.6% in H. pylori-negative and 49% in H. pylori-positive patients. CONCLUSIONS: The combination of 120 mg omeprazole daily and 2.25 g amoxicillin daily with its H. pylori cure rate of around 90% is one of the best tolerated and most effective treatment regimens.

Adolescent↗
PubMed1995

Pharmacokinetics and bioavailability of rhIGF-I/IGFBP-3 in the rat and monkey.

Circulating IGF-I exists primarily as part of a ternary 150 kDa complex comprising equimolar amounts of IGF-I, IGFBP-3 and acid labile subunit (ALS). It is also known that in contrast to IGF-I and IGFBP-3 there exists a substantial quantity of unbound ALS in the circulation. As part of our preclinical development program, we have investigated the pharmacokinetic properties of a complex of human recombinant IGF-I and IGFBP-3. Systematic administration of rhIGF-I/IGFBP-3 results in binding of this binary complex to endogenous free ALS and thus leads to increased circulating levels of 150 kD ternary complex (IGF-I/IGFBP-3/ALS). In contrast to the administration of free IGF-I, IGF-I/IGFBP-3 dosing leads to increased systemic IGF-I exposure (i.e. increased area under the time vs. serum concentration curve or AUC) and decreased clearance (CL). Upon administration of equimolar doses of IGF-I/IGFBP-3 to the rat and monkey, it was found that in the monkey AUC was increased and CL decreased when compared to the rat. In addition, the pharmacokinetic profile suggests that saturation of excess ALS occurs at considerably lower doses of rhIGF-I/IGFBP-3 in the monkey than in the rat. Finally, the bioavailability of rhIGF-I/IGFBP-3 was assessed in the rat and found to be approximately 85% and 50% after intramuscular and sub-cutaneous administration, respectively. It was concluded that the formation of the 150 kD ternary complex had a significant impact on increasing the systemic exposure to rhIGF-I when administered as the binary complex (rhIGF-I/IGFBP-3). In addition, IGFBP-3 increases the therapeutic index of rhIGF-I even at doses that significantly exceed the saturation of ALS.

Animals↗
PubMed1995

Systemic administration of rhIGF-I or rhIGF-I/IGFBP-3 increases cortical bone and lean body mass in ovariectomized rats.

The purpose of this study was to compare dose-related effects on cortical bone and lean body mass following subcutaneous administration of rhIGF-I alone, or bound to an equimolar amount of rhIGFBP-3 to adult Ovx rats. At the age of 16 weeks, rats were ovariectomized or sham-operated and were allowed 8 weeks to develop osteopenia. After being divided into control (saline treated) or treatment groups, rats were injected daily during an 8-week period with 0.9 and 2.6 mg/kg of rhIGF-I, or with 0.9, 2.6, and 7.5 mg/kg of rhIGF-I bound to rhIGFBP-3. Fluorescent bone markers were given 9 and 2 days prior to necropsy. Body weights and lean body mass were monitored throughout the experiment. Cortical bone histomorphometry was performed on tibial cross-sections at the tibiofibular junction, and endochondral bone growth was measured at the distal femoral metaphysis. All rats treated with rhIGF-I or the rhIGF-I/IGFBP-3 complex had increased body weights, corresponding to a dose-dependent increase in lean body mass. Endochondral growth was slightly increased in all experimental groups, but was not dose-dependent. A dramatic increase in periosteal, modeling-dependent formation, coupled with decreased or unchanged resorption on the endocortical envelope resulted in a dose-dependent increase in cortical thickness and cross-sectional area in groups treated with the complex of rhIGF-I/IGFBP-3. This complex appeared to be more effective in promoting positive musculoskeletal changes than rhIGF-I alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

The effect of systemically administered rhIGF-I/IGFBP-3 complex on cortical bone strength and structure in ovariectomized rats.

The action of systematically administered recombinant human insulinlike growth factor-I (rhIGF-I) complexed to its natural binding protein-3 (rhIGFBP-3) on cortical bone dynamic, structural, and mechanical properties was tested in previously ovariectomized (Ovx) rats. Bilateral ovariectomy or sham surgery was performed on 16-week-old female Sprague-Dawley rats. Eight weeks after surgery basal Sham and Ovx rats were killed to establish baseline cortical bone values before the initiation of treatment with rhIGF-I/IGFBP-3 complex. At that time, Ovx rats had increased body weight and body fat mass with reduced femoral BMC and BMD relative to basal Shams. Bone formation rates in Ovx rats were increased on both cortical envelopes relative to time-matched controls. The thickness of the inner lamellar bone layer and average cortical width were reduced due to increased endocortical erosion. A similar ratio between Sham and Ovx rats in body mass and composition and femoral BMC and BMD continued throughout the experiment. Sixteen weeks after surgery bone formation rates at both cortical envelopes in Ovx rats were reduced relative to Shams, but endocortical erosion remained high causing a further decrease in thickness of the inner lamellar layer. As a result of periosteal bone modeling. Ovx rats exhibited a larger femoral cross-sectional area and periosteal perimeter, as well as a thicker outer lamellar layer. Newly deposited periosteal bone increased ultimate torque values in the Ovx rats relative to Shams at 16 weeks. Treatment of Ovx rats with the rhIGF-I/IGFBP-3 complex increased body weight, lean body mass, and femoral BMC and BMD.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1995

Incidence of acute angle-closure glaucoma after pharmacologic mydriasis.

PURPOSE: To study the incidence of acute angle-closure glaucoma secondary to pupillary dilation and to identify screening methods for detecting angles at risk of occlusion. METHODS: We studied 5,308 respondents to the Baltimore Eye Survey, a cross-sectional, population-based survey conducted in a multiracial urban community. We measured incidence of acute angle-closure glaucoma after pharmacologic mydriasis and the specificity and sensitivity associated with three screening criteria in identifying those with potentially occludable angles. The screening factors were presence of shallow anterior chamber on penlight examination, history of glaucoma, and blindness. RESULTS: Of the 4,870 subjects whose eyes were dilated on screening examination, none developed acute angle-closure glaucoma. However, 38 patients of the 1,770 who were referred for definitive eye examination were judged to have occludable angles on the basis of gonioscopic methods. Of note, subjects aged 70 years and more were three times more likely to have occludable angles than those aged 40 to 69 years (P < .004) In 14 black subjects with occludable angles, six were detected by history of glaucoma and not by shallow anterior chamber configuration; alternatively, in 24 white subjects, 11 (46%) were detected on the basis of shallow anterior chambers (Fisher's exact test, P = .014). When the three screening factors were considered alone and in combination, the most effective combination for predicting a potentially occludable angle was to use shallow anterior chamber on penlight examination and history of glaucoma. These criteria provide 60.5% sensitivity and 93.3% specificity. CONCLUSION: If screening is performed accurately and the results are negative, the risk of dilating a potentially occludable angle was less than one in 333 subjects (negative predictive value, 0.997) in this population.

Acute Disease↗
PubMed1995

Cataract surgery in one eye or both. A billion dollar per year issue.

PURPOSE: To measure the relative effect of cataract surgery in the second eye compared with the first eye on functional impairment, satisfaction, and vision problems. METHODS: Seventy-five randomly selected ophthalmologists in three cities in the United States were enrolled in a National Study of Cataract Outcomes. They, in turn, referred eligible, sequential patients scheduled for first-eye cataract surgery. Interviews were conducted at enrollment, 4 months after first-eye surgery, and 12 months after first-eye surgery. An attempt was made to conduct a special, preoperative interview of those patients scheduled to undergo second-eye surgery before the 4-month interview. Each interview included administration of the VF-14 (a 14-item questionnaire that assessed visual function), as well as questions about symptoms possibly related to cataract, "trouble with vision," and satisfaction with vision. RESULTS: Seven hundred seventy-two patients were enrolled in the study, and interview data to 12 months were obtained from 669 (86%) patients. Of these patients, 243 (36%) underwent cataract extraction in the second eye during the 12-month period of observation. Overall, subjects who underwent cataract surgery in both eyes during the 12-month period had 61% greater improvement in VF-14 score (P < 0.001), 27% more decline in trouble with vision (P < 0.001), and 24% greater improvement in satisfaction with vision (P < 0.001) compared with those who underwent surgery in only one eye. CONCLUSIONS: Cataract surgery in the second eye of patients with bilateral cataract is associated with clinical and statistically significant improvement in functional impairment, trouble with vision, and satisfaction with vision.

Aged↗
PubMed1995

Predictors of outcome in patients who underwent cataract surgery.

PURPOSE: To identify preoperative patient characteristics associated with a lack of improvement on one or more measures 4 months after cataract surgery. METHODS: The authors collected preoperative and 4-month postoperative information on 552 patients undergoing first-eye cataract surgery from the practices of 72 ophthalmologists in three cities. The principal outcomes assessed were (1) Snellen visual acuity, (2) a cataract-related symptom score (possible range: 0, 0 of 6 symptoms present or bothersome, to 18, all 6 symptoms very bothersome), and (3) a measure of functional impairment in patients with cataract--the VF-14 score (possible range: 0, inability to perform any of the applicable activities, to 100, no difficulty performing any of the applicable activities). Multiple logistic regression was used to assess the association between preoperative patient characteristics and failure to improve on one or more outcome measures. Multiple linear regression was used to estimate the adjusted rate of lack of improvement in one or more outcome measures for one group of patients compared with another. RESULTS: Although 91 patients (16.5%) failed to improve on one or more of the outcome measures assessed, only 2 (0.4%) failed to improve on all three measures. The 91 patients who did not improve on at least one measure were approximately one sixth as likely to be satisfied with their vision postoperatively as the 461 patients who improved on all three outcome measures. Preoperative age of 75 years of age or older, VF-14 score of 90 or higher, cataract symptom score of 3 or lower, and ocular comorbidity (glaucoma, diabetic retinopathy, or age-related macular degeneration) were associated independently with increased likelihood of not improving on one or more measure (odds ratio: 3.57, 2.10, 3.29, and 2.16, respectively). The mean adjusted rate of failure to improve on at least one of the outcome measures ranged from 20.5% to 26.5% for patients with these preoperative characteristics compared with 8.8% to 13.8% for those patients without them. The preoperative level of Snellen visual acuity was not associated with the likelihood of not improving on one or more of the outcomes assessed. CONCLUSIONS: The authors conclude that specific preoperative characteristics (age, comorbidity, cataract symptom score, and VF-14 score) are independent predictors of patient outcome after cataract surgery.

Aged↗