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Biomedical subjects

A Preston

Publications and source records attributed to A Preston.

At least 37 records · Page 2Linked to original sources
PubMed1996

Altered lipopolysaccharide characteristic of the I69 phenotype in Haemophilus influenzae results from mutations in a novel gene, isn.

The 169 phenotype of Haemophilus influenzae results from a mutation leading to a lipopolysaccharide molecule consisting only of lipid A and a single phosphorylated 2-keto-3-deoxyoctulosonic acid residue. In this paper we describe the identification of a gene which, when mutated, results in the 169 phenotype. We have named the gene isn. The predicted amino acid sequence of Isn is homologous to the product of the lmbN gene involved in the biosynthesis of the sugar-containing antibiotic lincomycin by Streptomyces lincolnensis. lsn is situated between two loci that are homologous to the dpp and art periplasmic permease systems in Escherichia coli. Northern (RNA) blot and primer extension analyses reveal that isn is transcribed as a monocistronic mRNA. Potential functions of Isn protein are discussed.

Amino Acid Sequence↗
PubMed1996

The lipooligosaccharides of pathogenic gram-negative bacteria.

Lipooligosaccharides (LOSs) are the major glycolipids expressed on mucosal Gram-negative bacteria, including members of the genera Neisseria, Haemophilus, Bordetella, and Branhamella. They can also be expressed on some enteric bacteria such as Campylobacter jejuni and Campylobacter coli strains. LOS is analogous to the lipopolysaccharide (LPS) found in other Gram-negative families. LOSs share similar lipid A structures with an identical array of functional activities as LPSs. LOSs lack O-antigen units with the LOS oligosaccharide structures limited to 10 saccharide units. The LOS species of pathogenic Neisseria can play a major role in pathogenesis through enhancing the resistance of the organism to killing by normal human serum. Other distinguishing characteristics of LOS are the structural and antigenic similarity of some LOS species to human glycolipids and the potential for certain LOSs to be modified in vivo by host substances or secretions. These modifications of LOS in different environments of the host result in synthesis of new LOS structures that probably benefit the survival of the pathogen. The LOS of N. gonorrhoeae can act as a ligand of human receptors, promoting invasion of host cells. It is becoming clearer that LOSs are crucial factors in the pathogenesis of bacteria that express them.

Animals↗
PubMed1989

What's new in pediatric uroradiology.

The diagnosis and treatment of infants and children with urinary tract abnormalities have recently been affected by three developments. First, hydronephrosis can be detected in the fetus on obstetrical ultrasonography. Prenatal detection has resulted in a marked increase in the number of neonates referred for uroradiologic evaluation. Ureteropelvic junction (UPJ) obstruction, ureterovesical junction obstruction (UVJ), and reflux have been found to be the most common causes of hydronephrosis. Prophylactic antibiotics begun soon after delivery can prevent infection and its sequelae. Second, multicystic dysplastic kidney can now be accurately diagnosed preoperatively by a combination of ultrasonography and renal scintigraphy. This diagnostic certainty makes the decision to remove such a kidney a philosophical one. Third, it has been learned that reflux is sometimes familial. Nuclear cystography is an accurate and efficient method for screening asymptomatic family members.

Child↗
PubMed1982

Aldosterone-induced proteins in renal epithelia.

Similar aldosterone-induced proteins have been demonstrated in two renal epithelia, the urinary bladder of the toad, Bufo marinus, and epithelia formed by cells of the A6 line derived from the kidney of the toad, Xenopus laevis. The proteins are induced along with the stimulation of Na+ transport but their synthesis is not dependent on Na+ transport per se. In view of the similar characteristics of the aldosterone-induced proteins in these two different epithelia, we suggest that they may have an important role in aldosterone-induced Na+ transport.

Aldosterone↗
PubMed1979

Standards and environmental criteria: the practical application of the results of laboratory experiments and field trials to pollution control.

The derivation of standards and their application to the regulation of marine environmental quality are discussed, including the rôle of monitoring. The significance of experimentally determined sublethal effects in relation to the setting of environmental standards is considered. Contemporary approaches to pollution control are compared especially as they affect problems of standard setting.

Animals↗
PubMed1978

Nutritional status of elderly residents in Missouri.

Nutritional assessment of white persons over 59 who participated in the 1973 Missouri Nutrition Survey was based upon biochemical measurements, dietary intakes using food frequency histories, anthropometric measurements, and a dental examination. There were three major nutritionally related problems: poor dental health, obesity, and anemia. The mean for DMF, periodental index, and oral hygiene index for males was 20.5, 4.9, and 3.9, respectively; for females, 17.6, 3.6, and 2.5. Over one-half of both sexes were edentulous. Of the women 59% were greater than 119% of desirable weight compared to 22% of the men. Using guidelines from the Ten-State Nutrition Survey, the following percentages of men had low blood levels: 20, hemoglobin and serum iron; 2, plasma vitamin A; 6, plasma carotene; 1, serum vitamin C; and 0, serum albumin. The percent of women with low biochemical levels were: 11, hemoglobin; 10, serum iron; 7, plasma vitamin A; 1, serum vitamin C; and 2, serum albumin. None of the subjects had low or deficient levels of erythrocyte glutathione reductase. One-half of the women compared to one-fifth of the men had consumed diets with one or more nutrients below 67% of the 1974 Recommended Dietary Allowances.

Aged↗
PubMed1977

The study and control of environmental radioactivity and its relevance to the control of other environmental contaminants.

The history of radioactivity as an environmental contaminant is briefly traced. The basic principles concerning radiological protection and their application to the natural environment are reviewed. The relevance of these aspects of radiological protection philosophy and methodology to the control of other environmental contaminants is examined, especially the development and application of basic standards to waste disposal situations. It is concluded that many of the control procedures developed for radioactivity could be applied with advantage to other potential pollutants.

Air Pollutants, Radioactive↗
PubMedDate not supplied

The "pseudo-ring-sling" complex in unilateral pulmonary agenesis. Case report.

Unilateral pulmonary agenesis is described in an infant. Computed tomography (CT) was responsible for identification of an anomalous course of the pulmonary artery and for providing information of prognostic importance regarding tracheal dimension in this rare condition.

Cystic Adenomatoid Malformation of Lung, Congenita↗