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Biomedical subjects

A Sommer

Publications and source records attributed to A Sommer.

At least 343 records · Page 19Linked to original sources
PubMed1986

Primary structure and cDNA cloning of human fibroblast collagenase inhibitor.

We report the primary structure and cDNA cloning of human fibroblast collagenase inhibitor, a glycoprotein that appears to play a central role in modulating the activity of a number of metalloendoproteases of connective tissue origin including collagenase, gelatinase, and proteoglycanase. Secreted human fibroblast collagenase inhibitor was purified and subjected to automated Edman degradation. The secreted protein consists of 184 amino acid residues; it contains two sites of N-linked oligosaccharide linkage and six disulfide bonds. Synthetic oligonucleotide probes based on selected amino acid sequences of the inhibitor were used to screen a lambda gt10 cDNA library from a human fibroblast line. Two overlapping cDNA clones were characterized to determine the complete coding and noncoding sequences of the specific mRNA. The amino acid sequence deduced from the nucleotide sequence agrees with that determined by protein sequencing. One clone appears to contain the complete 5' end and, in addition, the cDNA sequence predicts a 23-amino acid leader peptide. The other clone represents the 3' end of the mature message and includes a short poly(A)+ tract. This 3' sequence is remarkably similar to a reported cDNA encoding part of the protein derived from mouse fibroblast poly(A)+ RNA. However, this inhibitor has no substantial homology with previously sequenced protease inhibitors.

Amino Acid Sequence↗
PubMed1986

[Nitrogen metabolism in the large intestine of ruminants. 2. Metabolism of i.v. infused 15N-urea by additional supply of fermentable material to the large intestine of bulls].

The experiment was carried out on 3 bulls with body weights of 201, 168 and 190 kg, respectively. The animals were equipped with a ileo caecal re-entrant cannula and with catheters in the jugular veins on both sides. The pelleted ration was composed of straw 70-72%, cereals 10%, molasses 12-41%, ammoniumhydrogencarbonate 3%, urea 2% and mineral mixture 1%. During a preliminary period ileal digesta were collected, deep-freezed and stored. During the main experiment 15N-urea was infused intravenously for 24 hours. In this period and during the following 6 hours outflowing ideal digesta were collected quantitatively. At the same time precollected, unlabelled digesta together with a supplement of partly hydrolysed straw meal were reintroduced into the caecal part of the cannula. Plasma urea-N, urinary-N as well as several N-fractions of faeces and digesta were analysed for 15N abundance. A urea flux rate of 27.9 +/- 3.4 mumol per minute per kg 0.75 was estimated. It was calculated that 52% of this amount of urea was transferred into the digestive tract. In both, digesta and faeces NH3-N was highest 15N-labelled indicating a direct urea entry and degradation in both segments of the digestive tract. The amounts of 15N-excess found during the period of digesta replacement were in faeces 0.25 and in ileal digesta 4.02% of the infused amount of 15N. Although the microbial utilization of endogenous urea-N was generally low in the large intestine there was a clear stimulation of this process due to the additional supply of the large intestine with a fermentable source.

Animals↗
PubMed1986

Breast-feeding, weaning patterns, and the risk of xerophthalmia in Southern Malawi.

A case-control study of breast-feeding and weaning patterns associated with xerophthalmia was conducted among children aged 24-71 mo in Southern Malawi in 1983. One hundred fifty-two children with active xerophthalmia were compared to 151 clinically normal children matched on age (+/- 12 mo), sex, and village of residence. All children were initially breast-fed; however, children with xerophthalmia began weaning onto porridge (p = 0.05) and ceased breast-feeding earlier (p less than 0.01 for 24-47 mo olds), had a shorter weaning interval (p less than 0.005), and were fully weaned from the breast for a longer duration (p less than 0.025) than the controls. The association between earlier cessation of breast-feeding and subsequent xerophthalmia was strongest during the immediate post-weaning years. These findings imply a protective role for breast-feeding against xerophthalmia in early childhood.

Age Factors↗
PubMed1986

Prevalence and severity of xerophthalmia in southern Malawi.

The first population-based study of xerophthalmia in Africa was conducted in the Lower Shire River Valley of Malawi in the autumn of 1983. A total of 5,436 children under six years of age were examined by three survey teams over an eight-week period. The prevalence of active xerophthalmia was 3.9%. Rates for night blindness and active corneal disease were more than five times the World Health Organization criterion for a problem of public health importance. Xerophthalmic corneal scarring occurred at a rate of 5.9/1,000, more than 10 times the World Health Organization criterion. All cases of bilateral blindness in this age group were considered to be due to vitamin A deficiency. Given recent evidence from Asia linking even subclinical vitamin A deficiency to increased risk of mortality and morbidity, this disease is not only a leading cause of blindness in this area, but may have an important impact on child survival as well.

Child, Preschool↗
PubMed1986

Blindness and visual impairment in southern Malawi.

There is a paucity of reliable information on the prevalence and causes of blindness in sub-Saharan Africa, and this produces problems in designing and evaluating blindness prevention programmes. To address this problem and to provide baseline data for the evaluation of such programmes, the government of Malawi, in conjunction with a number of agencies, conducted a population-based prevalence survey of ocular disease in the Lower Shire River Valley in southern Malawi, an area where blindness is common. The prevalence of bilateral blindness found (1.27%) is similar to that in other developing countries and represents a significant public health problem. At least 60% of this blindness is preventable or easily reversible.

Adult↗
PubMed1986

Childhood blindness from corneal ulceration in Africa: causes, prevention, and treatment.

Corneal scarring is responsible for approximately 70% of blindness in children in African countries. Recent studies confirm that measles infection is a common predisposing factor and that vitamin A deficiency is responsible for the majority of bilateral corneal ulceration. Herpes simplex keratitis (caused by human (alpha) herpesvirus types 1 and 2), ophthalmia neonatorum, and the use of traditional eye medicines also constitute significant causes of corneal ulceration in children in Africa. Intervention strategies, the management of corneal ulceration in children, and areas for future investigation are discussed.

Africa↗
PubMed1986

A simple surveillance system for xerophthalmia and childhood corneal ulceration.

A simple cost-effective surveillance system is described for reporting cases of xerophthalmia and childhood corneal ulceration. The system is suitable for use by ophthalmic auxiliaries in developing countries.Presented are the results of a 2-year surveillance involving 15 hospitals in 11 areas of the United Republic of Tanzania. Cases of xerophthalmia in its early stages (characterized by night blindness or Bitot's spots) were found in all areas surveyed. Of almost 300 cases of unilateral and bilateral corneal ulceration, 46% and 79%, respectively, followed a recent infection with measles. The single most important cause of bilateral corneal ulceration was vitamin A deficiency. The surveillance system has proved to be particularly useful as a first step in defining the type and distribution of serious corneal disease in children.

Child↗
PubMed1985

Automated differential threshold perimetry for detecting glaucomatous visual field loss.

Because early glaucomatous visual field defects occur asymmetrically across the horizontal meridian, we analyzed data from automated perimetry by comparing sums of threshold values of corresponding groups of points in the superior and inferior hemispheres of the central 30 degrees tested by the Humphrey Field Analyzer. We developed patterns and criteria from 25 early glaucomatous and 36 normal control eyes to achieve optimal balance between sensitivity (96%) and specificity (86%). Application of these criteria to an independent group of 27 glaucomatous and 105 control eyes yielded a sensitivity of 88.9% and specificity of 85.7%. Minor modification of the criteria improved sensitivity and specificity to more than 90% for both patients and controls.

Adult↗
PubMed1985

Preparation and characterization of two monoclonal antibodies against different epitopes in Escherichia coli ribosomal protein L7/L12.

Two monoclonal antibodies with specificities for Escherichia coli 50 S ribosomal subunit protein L7/L12 were isolated. The antibodies and Fab fragments thereof were purified by affinity chromatography using solid-phase coupled L7/L12 protein as the immunoadsorbent. The two antibodies were shown to recognize different epitopes; one in the N-terminal and the other in the C-terminal domain of protein L7/L12. Both intact antibodies strongly inhibited polyuridylic acid-directed polyphenylalanine synthesis, ribosome-dependent GTPase activity, and the binding of elongation factor EF-G to the ribosome. Ratios of antibody to ribosome of 4:1 or less were effective in inhibiting these activities. Neither antibody prevented the association of ribosomal subunits to form 70 S ribosomes. The Fab fragments showed similar effects.

Animals↗
PubMed1985

Race and primary open-angle glaucoma.

A comparison of racial distributions for three groups of patients showed that 115 of 140 patients (81.6%) with open-angle glaucoma, 221 of 392 patients (56.4%) with ocular hypertension, and 1,028 of 2,109 patients (48.7%) in a random sample were black. Average age at diagnosis was significantly (P = .006) higher for whites than for blacks (69.1 years vs 63.7 years). Black patients with primary open-angle glaucoma had a significantly larger mean cup-disk ratio (P less than or equal to .002) and a higher but not significantly higher mean intraocular pressure at the time of diagnosis. Advanced glaucomatous visual field loss was more frequent at the time of diagnosis in blacks (43 of 129 patients or 33.3%) than in whites (five of 27 patients or 18.5%), but this difference was not significant.

Adult↗
PubMed1985

False-positive reporting of Down syndrome on Ohio and New York birth certificates.

Although correction for underreporting of congenital malformations on birth certificates is included in most studies, inaccuracy of reporting has not been widely examined. Two separate investigations were conducted on the inaccuracy of Down syndrome (DS) reporting on birth certificates; ie, false-positive cases in which an individual coded as DS did not in fact have DS. In Ohio, 824 individuals were coded as DS on their birth certificate during 1970-1981. Of these, a definitive determination as to whether or not they had DS was made on 778 by using cytogenetic data, medical records, the state's birth defects registry, school records, and by questioning physicians. Fifty-seven false-positives were found, indicating a 7.8% level of coding inaccuracy for all races and 6.9% for whites only. Nine of these arose from miscodings during data processing; 48 were misdiagnosed as DS. This can be contrasted with false-negatives also studied in Ohio, where 66.1% of DS cases were not reported on the birth certificate. No statistical differences were observed between false-positives and true DS in the distribution of sexes, in population size of county of birth, or in year of birth (although there was a declining false-positive rate over the 12 year period). The percentage of DS false-positives, however, was significantly higher for younger maternal ages (greater than or equal to 30 years) than older ones (greater than or equal to 30 years) and for nonwhites compared to whites. Further, there was a strong negative correlation between the percentage of false-positives and the degree of certainty expressed in reporting DS on the birth certificate.

Adolescent↗
PubMed1985

[Nitrogen metabolism in the large intestine of ruminants. 1. Metabolism of i.v. infused 15N-urea without additional carbohydrate supply to the large intestine].

The experiments were carried out on 3 bulls (body weight: 172, 229 and 193 kg), equipped with ileo-caecal cannulas and with catheters in the jugular veins on both sides. The offered pelleted ration consisted of straw 73%, molasses 12%, cereals 10%, ammonium hydrogen carbonate 3% and urea 2%. Feed intake amounted to about 3 kg per animal and day. During a preliminary period of 5 days 50% of ileal digesta were collected for 12 hours daily, deep-freezed and stored. In the main experiment 15N-urea was infused intravenously for 24 hours. During this period and during the following 6 hours ileal digesta were collected and replaced by precollected, unlabelled digesta. The urea metabolism was estimated by the 15N-labelling of blood urea, by the 15N-excretion via faeces and urea, by the appearance of 15N in ileal digesta and by the 15N-labelling of faecal NAN, NH3 and bacterial fraction. The time course of the 15N-labelling of plasma urea during infusion can be described by an exponential function. The urea flux rate was estimated from the calculated plateau value. The flux rate for the 3 animals was 28.8, 30.7 and 34.8 mumol per minute per kg0.75, respectively. During the infusion of 15N-urea 1.0-2.4% of the infused amount of 15N' appeared in ileal digesta, half of it in the TCA precipitable fraction. At the same time the 15N-labelling of faecal NH3 increased sharply, however, the 15N-labelling of the faecal bacterial fraction was smaller by one order of magnitude. Deficiency of fermentable substrates and problems of inhomogenity of the NH3 pool are supposed as reasons for this result. 30 to 50% of the urea flux entered the digestive tract, the direct entry of urea into the large intestine seems to be only very low.

Animal Feed↗
PubMed1985

The ecology of trachoma: an epidemiological study in southern Mexico.

A total of 1097 people in two communities in Chiapas, Mexico, were examined for trachoma, and information was obtained about personal and family hygiene. Trachoma was hyperendemic; approximately 25% of those under 10 years old were found to have significant inflammatory trachoma and almost 100% of those aged over 40 years had cicatricial trachoma, although the prevalence of trachoma differed significantly between the two communities. Risk factor analysis was performed by contingency table analysis and chi(2) testing. The most important parameter associated with the occurrence and severity of inflammatory trachoma in children was the frequency of face washing. Children who washed their faces 7 or more times per week had significantly less trachoma than those who washed less often (chi(2) (2df) = 28.7; P < 0.001). This effect was independent of age, use of clean water and soap, or use of clothes to dry the face. Children who washed infrequently and who used clothes to dry the face or clean the nose were more at risk for trachoma. No parameters of family hygiene or socioeconomic status correlated with the amount of trachoma in a family.These data confirm and quantify for the first time the long-held belief that trachoma is associated with poor personal hygiene and suggest potentially effective and efficient intervention strategies.

Adolescent↗