Search PubMed⌕ Search

Biomedical subjects

S Johnson

Publications and source records attributed to S Johnson.

At least 505 records · Page 28Linked to original sources
PubMed1982

Improved preparation of poly(A) Sepharose and the isolation of oligo(U) containing heterogeneous nuclear RNA from Friend erythroleukemic cells.

When poly(A) sepharose (prepared according to previously published procedures) was stored in aqueous buffer at 4 degrees C for 5 days or longer, it bound nonspecifically a high percentage of the input RNA which could not be eluted with formamide. We have found that treatment with ethanolamine, followed by dehydration with ethanol yielded poly(A) sepharose which was stable for many months and possessed a low degree of nonspecific binding. Chromatography on poly(A) sepharose permitted the specific isolation of that fraction of Friend erythroleukemic cell heterogeneous nuclear RNA (hnRNA) which contained oligo(U) sequences. Approximately 10% of the hnRNA which contained a poly(A) sequence [poly(A+)] also contained an oligo(U) sequence. Interestingly, prior HCHO denaturation of the hnRNA enhanced binding of the poly(A+) oligo(U+) hnRNA to poly(A) sepharose by tenfold. This suggested that the oligo(U) sequence may be in a region with secondary structure, possibly an intramolecular duplex with the 3' poly(A). Friend cell oligo(U) sequences ranged from 20 to 50 nucleotides in length and, thus, were similar to the oligo(U) sequences which heretofore had only been shown to be present in HeLa cell hnRNA. These results established that rodent cell hnRNA contain oligo(U) sequences and demonstrate, for the first time, that hnRNA containing both a poly(A) and an oligo(U) sequence can be separated from other classes of hnRNA. In addition, conditions are presented for the removal of HCHO from nucleic acid.

Animals↗
PubMed1982

A mobile intensive care unit based on a standard ambulance trolley bed.

An inexpensive, versatile Mobile Intensive Care Unit is described. By designing the unit around a standard ambulance trolley no running costs are incurred in the maintenance of a purpose-built unit based on an ambulance used purely for this purpose. The equipment is portable and compact and can be transported by any available means, including a taxi, to the referring hospital. Only when the patient is ready for transfer is an ambulance asked for, making the minimum use of emergency ambulance time. It contains all the equipment necessary to monitor and ventilate artificially a critically ill patient during transfer and all the drugs and disposables to treat any emergencies that may arise in this period.

Equipment Design↗
PubMed1982

Dracontiasis in Rajasthan. VI. Epidemiology of dracontiasis in Barmer district, Western Rajasthan, India.

Epidemiology of guinea worm disease was studied in relation to sex, age, community and drinking water of inhabitants of 12 desert villages in Barmer district, Western Rajasthan, India. Data were also stratified with respect to first infection and reinfection. Infection was significantly (p less than 0.001) more prevalent in males (7.5%) than females (4.1%). Among all age groups peak infection (9.9%) occurred in those aged 30-39 years. Non-vegetarian communities had a higher incidence than vegetarian communities. Between-community difference was significant (p less than 0.01). First infection cases (11.0%) peaked in those aged 20-29 years while people aged 30-39 years were most susceptible to reinfection (84.6%). Between-age differences with respect to first and reinfection were insignificant (p greater then 0.05). Of various water sources reported pond water was a major source of contamination. 82.7% of the population examined was at risk of developing guinea worm infection at any time. No effective treatment is yet available.

Adolescent↗
PubMed1982

Changes in quantitative norepinephrine levels in delayed pig flank flaps.

A quantitative norepinephrine assay was used to follow tissue norepinephrine concentrations serially in bipedicle delayed pig flank flaps. In contrast to a previous study by Palmer, norepinephrine concentration decreased significantly after 24 hr, but then gradually returned to normal at 10 days. This suggests that the pig flank flap maintains much of its adrenergic innervation following bipedicle delay. It appears unlikely that adrenergic denervation explains the delay phenomenon in this model. The combined results of this study and others suggest that the degree of adrenergic denervation of a flap is determined by the anatomic layout of the flap with respect to the underlying cutaneous adrenergic neural anatomy. This experiment suggests that the effectiveness of adrenergic blocking agents in improving flap survival is dependent on the degree of adrenergic denervation of the flap.

Animals↗
PubMed1982

Biochemical characterization of canavalin, the major storage protein of jack bean.

The structure of canavalin, a jack bean (Canavalis ensiformis) protein homologous to phaseolin, the major seed storage protein of Phaseolus vulgaris, has been investigated by x-ray crystallography and found to be a hexamer composed of three identical pairs of similar but nonidentical subunits related by a perfect 3-fold axis and pseudo dyad axes (strict C(3) and pseudo D(3)). One member of each pair of subunits is derived from the amino terminal half of a precursor polypeptide of molecular weight 49,000 and the other from its carboxy terminal half. Thus, the crystallographic evidence indicates that the precursor polypeptide is a tandem duplicate and is structurally redundant (McPherson A. 1982 J Biol Chem 255: 10472). A number of physical and chemical properties of the protein in both the uncleaved and the cleaved form were investigated. These included the native molecular weights, amino acid analyses, number of exposed sulfhydryl groups, carbohydrate content, metal ion analysis, crystallization behavior, and the fate of the protein in developing seeds. It was also found that the purified precursor protein possesses a substantial level of alpha-d-mannosidase activity and seems to share a number of other physical and chemical properties with that enzyme.

Journal Article↗
PubMed1982

The effect of the scaleless gene, sc, on growth performance and carcass composition of broilers.

Two experiments were conducted in which featherless broilers (scaleless, sc/sc) were compared with feathered broilers for growth and body composition characteristics at environmental temperatures of 22, 34, and 38 C. The sc gene reduces growth and efficiency at 22 C but at 38 C the sc/sc broilers gain more, eat more, and are more efficient than feathered broilers. They achieve greater live, New York dressed, and eviscerated weights and consistently have greater eviscerated yields. The sc/sc broilers have more protein and mineral content and less fat than the feathered broilers.

Animals↗
PubMed1982

Nutrition knowledge and attitudes of elementary school students after receiving nutrition education.

The effect of a nine-week nutrition education program on nutrition knowledge and selected nutrition/food attitudes of kindergarten through sixth grade pupils was examined. Children in the experimental group participated in the program for a nine-week instructional period; those in the control group participated later. Knowledge and attitude assessment instruments were administered to both groups immediately before and after the instructional period. In the lower grades (kindergarten through grade 3), responses on two of the three attitude scales were positively influenced by the nutrition education program. On the third attitude scale there was a trend toward a positive effect in all but one of the lower grades, but the trend was significant only in first grade. In the upper grade levels (4 through 6), the effect of nutrition education on the nutrition and food attitude scale responses was mixed; it tended to be most positive in grade 4 and least positive in grade 6. The nutrition education program also had a significant positive effect on the nutrition knowledge score of pupils in all grades except sixth. In this grade, the trend was positive but was not significant.

Attitude to Health↗
PubMed1981

INfluence of biotin supplementation on sow reproductive efficiency.

A herd of 116 sows was divided into two groups. Animals in one group had their food supplemented with 1160 micrograms/day of biotin in pregnancy and 2320 micrograms/day in lactation, over a 12-month period. The other group served as a control. Those receiving biotin farrowed significantly more live pigs in parities 2 and 4 than in the control animals; the increase in parity 3 only just failed to reach significance. There was no consistent effect on the weaning to service internal although a significant difference (P = 0.05) was seen with the third litters.

Animals↗
PubMed1981

Inhibition of desaturation of palmitic, linoleic and eicosa-8,11,14-trienoic acids in vitro by isomeric cis-octadecenoic acids.

The effects of the positional isomers of cis-18 : 1 acids on the desaturation of 18 : 2 omega 6 leads to 18 : 3 omega 6 (delta 6 desaturase), 20 : 3 omega 6 leads to 20 : 4 omega 6 (delta 5 desaturase) and 16 : 0 leads to 16 : 1 (delta 9 desaturase) were investigated using essential fatty acid deficient rat liver microsomes. The isomeric cis-18 : 1 acids were found to be inhibitory for the delta 6, delta 5 and delta 9 desaturases, and the position of the double bond is important in determining the degree of inhibition. The effects of the several cis-18 : 1 isomers on delta 6 and delta 5 desaturases were parallel in magnitude exept for the cis-delta isomer which gave 17.5% inhibition for delta 6 desaturase and no inhibition for delta 5 desaturase. The strongest inhibitor for delta 6 desaturase (cis-delta 8 18 : 1) was also the most potent inhibitor for delta 5 desaturase, and the weakest inhibitor for delta 6 desaturase (cis-delta 3 18 : 1) was the least effective inhibitor on delta 5 desaturase. The delta 9 desaturase was maximally inhibited by cis-delta 10 and delta 11 18 : 1 isomers. The cis-18 : 1 acid isomers in partially hydrogenated edible fats may have effects on the lipid metabolism through their inhibitory effects on the desaturases.

8,11,14-Eicosatrienoic Acid↗
PubMed1981

Rapid tests for esculin hydrolysis by anaerobic bacteria.

Esculin hydrolysis is one of the biochemical tests used in the identification of anaerobic microorganisms. The conventional method by use of growing microbial cells requires 24-48 hours of incubation. On the other hand, growth independent methods like the buffered esculin test, the spot test, and the PathoTec strip test utilize the presence of constitutive enzymes and, therefore, yield results in 1-4 hours. A total of 817 anaerobic organisms were used in this study to determine the sensitivity and specificity of the three rapid methods. All three rapid methods gave excellent correlation with the standard conventional method. Over 99% of the organisms gave comparable results with the spot test and the buffered esculin test within one hour; the PathoTec strip test required up to 4 hours. The former two were not only more rapid but also more economical than the PathoTec strip test.

Anaerobiosis↗