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J Best

Publications and source records attributed to J Best.

At least 109 records · Page 6Linked to original sources

Protein nitrogen unit precipitation procedure for allergenic extracts: collaborative study.

Protein nitrogen unit (NU) determination is one of the methods used to test and label the concentration of allergenic extracts. This recently standardized method is applicable to all allergenic extracts. One PNU/mL is equivalent to 1 X 10(-5) mg nitrogen determined to be in the material precipitated from 1 mL allergenic extract by phosphotungstic acid (PTA), a protein precipitant. The nitrogen is quantitated by the Kjeldahl method or another analytical method of equivalent accuracy and precision. A collaborative study of the optimized PNU precipitation method in which 6 samples were analyzed in duplicate by 6 laboratories using the Kjeldahl method for the determination of nitrogen yielded a mean of 0.1358 mg N/mL, a repeatability standard deviation and coefficient of variation of 0.0071 mg N/mL and 5.23%, respectively, and a reproducibility standard deviation and coefficient of variation of 0.0188 mg N/mL and 13.84%, respectively. The method has been adopted official first action.

Allergens↗

Preservation of normal cortical vasculature in ischaemic renal failure in the dog.

Ischaemic renal failure in the dog was studied by clamping one renal artery for 2 hr in 18 animals. Total renal blood flow was measured for 3 hr after this and only reduced by about 30%. Fine detail renal angiography showed a normal cortical perfusion pattern. Urine flow rates and creatinine clearances from these kidneys, however, were found to be grossly impaired over this period. Seven days later the angiogram of the oliguric kidney remained normal. Two-hour unilateral renal ischaemia in the dog leads to a form of acute renal failure with a striking disparity between glomerular perfusion and clearance, arguing agains a primary circulatory defect.

Acute Kidney Injury↗

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Economics, Nursing↗

Effect of prolonged hyperinsulinaemia on adipocyte insulin binding and action in normal man.

Prolonged moderate insulinaemia over 20 h in normal humans produces a significant reduction of in vivo insulin action. To examine the effects in man of such moderate hyperinsulinaemia on in vitro glucose metabolism, insulin-receptor binding, glucose transport and incorporation of glucose into lipid were determined in adipocytes isolated from paired gluteal fat biopsies, taken from six normal human volunteers before and 1 h after 20 h of exogenous hyperinsulinaemia (plasma insulin 38 +/- 3 mU/l). Specific binding of insulin to isolated adipocytes was not altered (6.7 +/- 0.7 versus 7.6 +/- 1.5% per 10(5) cells). Basal glucose transport of 3-O-[14C]methylglucose in the absence of insulin was reduced after hyperinsulinaemia (5.2 +/- 1.1 versus post 4.3 +/- 1.3 pmol/7 s per 10(5) cells, 0.1 less than P greater than 0.05; or expressed as percent of maximal response: 60 +/- 5 versus post 49 +/- 1%, P less than 0.05), but maximal transport (9.2 +/- 1.5 versus post 8.7 +/- 1.5 pmol/7 s per 10(5) cells) and ED50 (87 +/- 17 versus 67 +/- 15 pmol/l) were unchanged. Conversion of glucose into lipid, using 3-D-[3H]glucose, was unchanged basally, at maximal response or ED50 of the dose response curve. In conclusion, moderate 20 h in vivo hyperinsulinaemia in normal humans induces only a small change in basal vitro adipocyte glucose transport, and no change in insulin-receptor binding or in vitro incorporation of glucose into lipid. These data suggest that the adipocyte does not contribute to the impaired insulin action produced by in vivo moderate hyperinsulinaemia in man.

3-O-Methylglucose↗

Eye alignment and cortical binocularity in strabismic kittens: a comparison between tenotomy and recession.

Interocular alignment was assessed by corneal light reflex photography in 15 normal and 26 strabismic kittens. Strabismus was induced at 3-4 weeks of age by severing one extraocular muscle (tenotomy), by cutting and reinserting the muscle at another position on the ocular globe (recession), or by combining recession of the medial rectus muscle with resection of the lateral rectus muscle of the same eye. Nineteen strabismic and five normal kittens were followed longitudinally from 12 days to about 6 months of age. Three out of six longitudinally followed tenotomized cats and six out of the 13 recessed cats conserved their postoperative ocular deviation throughout the testing period ("large-angle strabismics"). Three tenotomized and seven recessed cats showed a transient deviation for 1-2 weeks after surgery, after which the interocular deviation diminished to values found in normal cats ("microstrabismic" cats). Both recessed-resected cats showed a transient interocular deviation. In spite of their different developmental histories, all cats showed a clear breakdown of binocularity in area 17. Large-angle strabismics showed a dominance of the non-operated eye, while in microstrabismic cats, both eyes were equally effective in driving cortical cells. It thus appears that a transient strabismus is sufficient to produce a reduction of binocularity in area 17.

Animals↗