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Biomedical subjects

R Hill

Publications and source records attributed to R Hill.

At least 271 records · Page 15Linked to original sources
PubMed1976

C- and Q-band polymorphisms in the chromosomes of three human populations.

The incidence of the various classes of C-band and Q-band polymorphisms on ten pairs of chromosomes in the human complement have been investigated in three Scottish populations, two from the mainland (newborn and 14 year olds) and one, of individuals over 65 years, from an island in the Outer Hebrides. Although there is an overall similarity between the populations, there are some differences, especially with the island group. For all populations, over 90% of the C-band size variants fall within the medium class. Rather more variation is found in the Q-band intensity polymorphisms: the island population appears to have fewer Brilliant and Intense variants than do the other two groups, 2-9 per person as compared to 4-2 and 3-9 for the newborn and 14 year olds respectively; this may be an age difference rather than a population difference.

Adolescent↗
PubMed1976

The segregation of human chromosome polymorphisms.

The inheritance of C-band and Q-band polymorphisms have been investigated in 32 families. C-band inversion and size polymorphisms appear to segregate in a Mendelian manner, with the possible exception of the very large variant of chromosome number 9 which may be selectively inherited. There is some evidence to suggest a preferential segregation of Brilliant Q-band polymorphisms but it may be that this is an artifact caused by insufficient data and scoring error.

Blood Cells↗
PubMed1976

Hydrogen ion concentration of human tears: Effects of prolonged eye closure.

Using a closed chamber microelectrode technique, human tear hydrogen ion concentration was measured following periods of eye closure of 6 to 8 hours and then compared with normal open eye findings from the same patients. Closed eye tears were found to be significantly more acid (average age difference = 26 nM/1) and required some 3 to 4 hours to return to average open eye levels. The population rate for this return averaged 6.9 nM/1/hr. This degree of acid shift measured for prolonged eye closure, however, remained, for the average patient, well within comfort limits commonly cited, and appeared insufficient to distrub the water content or optical parameters of hydrophilic polymers in common use today for therapeutic or cosmetic purposes.

Adult↗
PubMed1976

Kinetics of fibrinogen and platelet adherence to biomaterials.

The initial task was to establish a conceptually and materially simple test procedure that could quantitate and evaluate the thrombogenic potential of a biomaterial surface. Since the primary events of thrombus formation on prosthetic surfaces are believed to involve the deposition of a plasma protein monolayer followed by platelet adhesion to its fibrinogen component, it seemed reasonable to focus on the binding kinetics of fibrinogen and platelets to a commonly used biomaterial. Employing solutions of 125I-fibrinogen in buffered saline, the adsorption characteristics of several types of biomedical tubing could be compared, and the competition and exchange among plasma proteins at surface binding sites of PVC were evaluated. Human platelets with 51Cr were found to adhere to PVC surfaces proportional to surface fibrinogen concentration, but only in the presence of plasma; the circulation of labelled platelets in buffered saline only resulted in significant adherence to the native surface, while surface fibrinogen was inhibitory. Physiological concentrations of albumin were the most effective in preventing both fibrinogen adsorption and platelet adherence. The most important consequence of this work, perhaps, is the many avenues of future experimentation discovered from this methodological approach, not only in the thrombogenic evaluation of a specific biomedical surface, but also in the delineation of thrombogenic sequelae in general.

Adhesiveness↗
PubMed1975

The use of rapeseed meal as a protein supplement in poultry and pig diets.

Rapeseed meal would be used in much larger amounts in poultry and pig diets if its use was related solely to cost and nutritive value. In certain circumstances there are undesirable effects that severely lmiit its use. Most of the rapeseed meal available at present in the UK is strongly goitrogenic when fed to poultry or pigs, but it is not certain if this is necessarily harmful, nor if this is related to other effects that occur in particular situations and are clearly undesirable. From current data, diets in which rapeseed meal can be included most satisfactorily are those for broilers, growing pullets and finishing pigs. Plant breeders are actively selecting types of rape that have low or zero thioglucoside content and it is hoped that these new varieties will cause none of the ill-effects described in this review.

Animal Feed↗
PubMed1975

Indomethacin blockade of renal PGE-synthesis: effect on total renal and tubular function and plasma renin concentration in hydropenic rats and on their response to isotonic saline.

The effects of indomethacin (I), a blocker of prostaglandin (PG)-synthetase, was studied in rats in an attempt to elucidate the physiological role of renal PGE. Plasma-I-concentrations of 13-14 mug/ml reduced renal venous plasma PGE-concentration significantly from 216 to 85 pg/ml within 45 min. Urine flow and solute excretion decreased by 42% and 20%, respectively, while urine osmolality increased 450 mOsm. Inulin clearance (CIN) and proximal reabsorption rate was unaffected, while renal plasma flow (RPF) decreased by 18%. Plasma renin concentration decreased slightly but significantly. An i.v. saline load equal to 1% b.wt. given to I-treated rats failed to elevate significantly either urine flow, solute excretion, CIN, RPF or proximal reabsorption rate, but plasma renin decreased further. The normal inverse relationship between plasma renin and proximal reabsorption rate was absent. The data are consistent with the concept that intrarenal PGE plays in adjustment of renal vascular resistance, and support the concept of a physiological role of intrarenal PGE in regulating salt and water excretion. The data do not support any major physiological role of PGE in regulating proximal tubular function.

Animals↗