Search PubMed⌕ Search

Biomedical subjects

B A Lewis

Publications and source records attributed to B A Lewis.

72 records · Page 4Linked to original sources
PubMed1976

The sodium-retaining effect of renal nerve activity in the cat: role of angiotensin formation.

1. The effect of low-frequency stimulation of the renal nerves on renal function and renin release has been investigated. The experiments were performed in unilaterally nephrectomized, anaesthetized cats in which the nerves to the remaining kidney were sectioned. 2. When stimulation frequency was adjusted to reduce renal blood flow by approximately 15% for 15 min, glomerular filtration rate was hardly affected. The ratio sodium clearance/glomerular filtration rate was significantly reduced and plasma renin activity was significantly increased. 3. When the renal nerves were similarly stimulated in the presence of the beta-adrenergic receptor blocking agent, propranolol, the glomerular filtration rate was significantly reduced and the rise in plasma renin activity was significantly inhibited. The reduction of sodium clearance/glomerular filtration rate was as great as in the control animals. 4. The results are consistent with the view that the maintenance of glomerular filtration rate, during renal nerve stimulation which reduced renal blood flow, may be mediated by the local generation of angiotensin. The results also suggest that angiotensin does not play an important role in the sodium retention associated with increased renal nerve activity.

Aminohippuric Acids↗
PubMed1975

Basolateral plasma membranes of intestinal epithelial cells. Identification by lactoperoxidase-catalysed iodination and isolation after density perturbation with digitonin.

Lactoperoxidase-catalysed iodination was used to label intestinal epithelial cell sheets with 125I. The iodination was carried out under conditions that allowed little penetration of lactoperoxidase into the cells and membrane-bound 125I therefore provided an effective marker for following plasma-membrane fragments through subcellular-fractionation procedures. 2. After homogenization and isopycnic zonal centrifugation through sucrose gradients two peaks of membrane-bound 125I were detected. One coincided with brush border enzymes such as alkaline phosphatase, disaccharidases and L-leucine B-naphthylamidase, whereas the other was coincident with the major peak of (Na++K+)-stimulated ATPase (adenosine triphosphatase), which has been thought to be concentrated in the basolateral plasma membranes of these cells. Neither peak of 125I reflected the distribution of any marker for an intracellular organelle. 3. A larger proportion of the (Na++K+)-stimulated ATPase, and thus of the basolateral plasma-membrane material, was found in a crude 'mitochondrial' fraction. It was not readiily separated from mitochondria by conventional techniques of subcellular fractionation. 4. Treatment of the 'mitochondrial' fraction with digitonin increased the density of basolateral plasma membrane but had little effect on mitochondrial density. A purified preparation of digitonin-loaded basolateral plasma membranes was isolated at a density of 1.20-1.22 by isopycnic centrifugation. 5. The enzymic composition of this preparation of basolateral plasma membranes is compared with previous preparations isolated from intestinal mucosal 'scrape' materials and from isolated cells.

Adenosine Triphosphatases↗
PubMedDate not supplied

Subgrouping children with familial phonologic disorders.

Familial aggregation of speech and language disorders was examined as a basis of subgrouping children with phonologic disorders. Fifty-nine children with phonologic disorders were subgrouped according to whether or not other nuclear family members reported a history of speech/language disorders. Thirty-four subjects (58%) reported at least one other nuclear family member affected and 25 subjects (42%) reported no other nuclear family members affected. Groups were compared on measures of articulation, phonology, language, and oral motor skills to determine if the familial phonologic subgroup presented a unique profile of speech and language deficits. Significant group differences were not observed. However, children with positive nuclear family histories tended to perform more poorly than children without histories on all tasks, although not reaching significance. Although all parents were considered to have achieved normal adult articulation, parents of children with positive family histories also tended to perform more poorly than parents of children with negative histories. Results suggested that poorer oral motor coordination and productive phonology may distinguish individuals with familial phonologic disorders from individuals with phonologic disorders of unknown origin.

Child↗
PubMedDate not supplied

Academic outcomes in children with histories of speech sound disorders.

Tests of phonology, semantics, and syntax were administered to 52 preschool children (19 girls and 33 boys, age 4-6 years) with moderate to severe speech sound disorders. The children's performance on these tests was used to predict language, reading, and spelling abilities at school age (age 8-11 years). Language impairment at school age was related to poor performance on preschool tests of syntax and nonsense word repetition, while reading impairment was predicted by poor performance in all preschool test domains (phonology, semantics, and syntax). In contrast, spelling impairment was predicted by deficits in preschool tests of phonological processing as measured by the Word Discrimination subtest of the Test of Language Development - Primary 2. Family history for speech and language disorders did not predict language, reading, or spelling impairment at school age. However, family history for reading disorders was a good predictor of school-age spelling difficulties.

Child↗
PubMedDate not supplied

Alcohol expectancies and social deficits relating to problem drinking among college students.

Standardized questionnaires were administered to 116 male and female undergraduates to examine how social deficits and alcohol expectancies relate to alcohol use. Participants were classified as either problem or nonproblem drinkers based on the Rutgers Collegiate Substance Abuse Screening Test. Problem drinkers reported experiencing social anxiety, shyness, and lower self-esteem to a greater extent than nonproblem drinkers. Problem drinkers also held more positive alcohol expectancies than nonproblem drinkers. Contrary to our hypotheses, however, particular types of alcohol expectancies did not interact with specific areas of social functioning to influence problem drinking. Overall, these findings suggest that problem drinkers have positive expectations about the immediate effects of alcohol consumption even though drinking is linked to long-term impairment in social functioning.

Alcoholic Intoxication↗
PubMedDate not supplied

Follow-up of children with early expressive phonology disorders.

Fifty-two children identified at age 4 to 6 years as demonstrating a moderate to severe expressive phonology disorder were followed to the third and fourth grades. Children were classified into two groups based on the presence of an early phonology disorder in isolation (P) or the presence of a phonology disorder with other language problems (PL). At follow-up, articulation measures failed to differentiate the groups; however, the PL group performed more poorly than the P group on measures of phoneme awareness, language, reading decoding, reading comprehension, and spelling. The P group demonstrated poor spelling skills relative to their reading and language abilities, suggesting residual spelling weaknesses in these children. The PL group reported more nuclear family members with speech-language disorders and with reading disorders than the P group. Findings support previous research linking early language disorders with later reading difficulties.

Child↗
PubMedDate not supplied

Speech production skills of nuclear family members of children with phonology disorders.

The speech production skills of 38 school-aged siblings and 94 parents of children with phonology disorders were assessed by administering tasks involving the repetition of multisyllabic real and nonsense words, and "difficult-to-articulate" phrases and sentences. Results demonstrated that speech production, as measured by these tasks, continues to improve into adulthood. Furthermore, family members who reported histories of childhood speech and language problems performed more poorly on these challenging articulatory tasks than did individuals without such a history. These tasks were positively correlated with reading, spelling, and language achievement measures, thus suggesting a relationship between spoken and written language.

Adolescent↗
PubMedDate not supplied

Urea enzymatic dialysis procedure for determination of total dietary fiber.

A method that uses urea and enzymes for determination of total dietary fiber (TDF) in foods has been developed and compared with the AOAC enzymatic-gravimetric method (43.A14-43.A20). In the evaluation, results for crude protein and ash contamination were higher by the AOAC method, particularly for samples that form gels during ethanol precipitation. The new urea enzymatic dialysis (UED) method quantitatively recovered, with less variation, more of the purified and semipurified dietary fiber products. TDF recoveries for carboxymethylcellulose and locust bean gum were 98% (SD 3.3) and 95% (SD 6.1) by the AOAC method and 99% (SD 1.0) and 100% (SD 0.6) by the UED method, respectively. The UED method was the more effective in removing starch. For kale samples, starch recovery was 3.5 and 0.2% from TDF residues obtained using the AOAC and UED methods, respectively. Differences were not significant among replicate values for determination of TDF in foods by the UED method (P greater than 0.01). Preliminary studies suggest that the new method can separately determine soluble and insoluble dietary fiber. The data indicate that the UED method is more precise and accurate than the AOAC method.

Dialysis↗