Skeletal resistance to the calcemic action of parathyroid hormone in uremia: role of 1,25 (OH)2 D3

Studies were carried out to investigate the role of 1,25(OH)2D3 in the skeletal resistance to the calcemic action of parathyroid hormone. The change in serum calcium after the intravenous infusion of 2 U of parathyroid extract (PTE)/kg body wt/hr for eight hours was evaluated in thyroparathyroidectomized (T-PTX) dogs before, and one, two and three days after, induction of uremia by bilateral ureteral ligation (11 dogs) or by bilateral nephrectomy (8 dogs). In another six nephrectomized and T-PTX dogs, 0.68 ug of 1, 25 (OH)2D3/day was given on the day of nephrectomy and for two days thereafter. Serum creatinine in each day of the study was not different among the three groups. The study also included the evaluation of the effect of sham operation (five dogs) and the administration of 1,25 (OH)2D3 to dogs with normal renal function (four dogs) on the calcemic response to PTE, as well as the reproducibility of such a response in the same animal. The results showed that 1) the calcemic response to PTE was markedly impaired after one day of bilateral ureteral ligation or nephrectomy, but the impairment was more severe after nephrectomy; 2) the calcemic response to PTE after two or three days of bilateral ureteral ligation was similar to that seen at one day after nephrectomy; 3) 1, 25 (OH)2D3 partially restored the calcemic response to PTE in the nephrectomized animals to levels similar to those seen after one day of bilateral ureteral ligation; 4) sham operation did not affect the response to PTE, and repeated infusion of PTE produced similar changes in the concentrations of serum calcium. The data indicate that (a) a deficiency of 1,25 (OH)2D3 is at least partly responsible for the skeletal resistance to the calcemic action of PTH in uremia; (b) uremia, per se, may also contribute to this phenomenon; and (c) the kidney after one day of complete bilateral ureteral ligation may still produce 1,25 (OH)2D3, but this ability is compromised after two days of ureteral obstruction.     

Cryosurgery of the ureter in dogs

The effect of cryosurgery on the ureter has been studied in dogs. A single 1- or 2-min cryosurgical exposure produced stricture in two of eight animals. A tumoricidal cryosrugical dose consisting of three, 2-min exposures caused stricture in six of eight dogs. Histopathologic examination of the ureter after repetitive cryosurgery showed progressive, persistent loss of smooth muscle, fibrosis of the lamina propria, and early loss with subsequent regeneration of the transitional epithelium. Although there was no loss of ureteral integrity, the possibility of permanent ureteral damage should be considered with the use of cryosurgery.     

Bulling among yearling feedlot steers

The effect of ingestion of 250 ml X-ray contrast medium on resting gastrooesophageal sphincter pressure was studied in 10 normal human subjects. Twenty minutes after initiated intake of the contrast medium, a significant fall in sphincter pressure was recorded. In the light of studies on the neurogenic and hormonal regulation of the sphincter pressure it is attempted to account for this effect, and it is concluded that it must be a manifestation of a reflectory relaxation of the sphincter region. From a clinical point of view the consequence must be a demand for standardized conditions with regard to composition and pH of the contrast medium, time schedule and degree of abdominal compression in those cases in which radiological evaluation of the resistance against reflux is called for.     

Gas exchange during exercise in healthy people II. Venous admixture

1. Venous admixture/cardiac output ratio (Qva/Qt) has been measured in twenty-four healthy volunteer subjects of both sexes aged 20-71 years, at rest and during the steady state of treadmill exercise at two rates of work, and breathing air and breathing oxygen. 2. With oxygen breathing, Qva/Qt was considerably less during exercise than during the time subjects were taking either normal or deep breaths of oxygen at rest, and did not significantly increase with the intensity of exercise. It is postulated that the increase in ventilation during exercise opens most or all of those alveoli which, during oxygen breathing at rest, close because of critically low ventilation/perfusion (V/Q) ratios. 3. With air breathing, Qva/Qt fell from rest to exercise (especially in older subjects), presumably due to improved ventilation of alveoli at the lung bases. With an increase in work rate Qva/Qt increased in all age groups. This increase was not due to increase in the shunt fraction (Qs/Qt), nor to limitation of diffusing capacity; it arose from an increase in V/Q variance. 4. Equations have been derived for the prediction of normal Qva/Qt during exercise, with or without correction for the effects of increasing pulmonary capillary temperature. These effects do not materially influence the accuracy of prediction, but may be relevant to some of the interpretations. In particular, they provide a further indication that Qs/Qt probably cannot be measured by breathing oxygen at rest, even in deep breathing.     

Plasma progestins, estradiol, and luteinizing hormone following prostaglandin F2 alpha injection

Dairy animals, ranging from days 8 to 13 of the estrous cycle, were fitted with indwelling jugular catheters 1 day prior to either intramuscular injection of prostaglandin F2alpha free acid (30 mg, n=4) or intrauterine deposition of prostaglandin F2alpha free acid (10 mg, n = 3). Blood samples were collected at 6, 4, 2, and 0 h prior to administration of prostaglandin F2alpha and at 1, 3, and every 2 h thereafter until ovulation. Progestins, estradiol, and luteinizing hormone in plasma were measured by radioimmunoassay. Hormonal changes and interrelationships within animals were evaluated by least squares analyses. Decreases in progestins of plasma within 24 h indicated prostaglandin F2alpha induced luteolysis in six of the seven animals. Estradiol increased linearly from time of injection to 52 h postinjection. Intervals from administration of prostaglandin to onset of estrus, peak of luteinizing hormone, and ovulation were 74.9 +/- 21, 78.8 +/- 21, and 99.5 +/- 19 h.     

Increasing polyunsaturation of milk fats by feeding formaldehyde protected sunflower-soybean supplement

A practical means of protecting fats of a feed concentrate containing high polyunsaturated fatty acids is described. A ground mixture of 30% soybeans and 70% sunflower seeds was treated with 1% formaldehyde to protect the unsaturated lipids from microbial hydrogenation in the rumen. This was fed as a supplement to two Holstein cows in amounts that were doubled weekly. These ranged from 524 to 8384 g/day and provided successively increasing intakes of 100, 200, 400, 800, and 1600 g of linoleic acid daily. Percent milk fat increased by more than one, and linoleic acid (C18:2) of milk fat increased from 2.5 to 20% with compensatory declines in myristic (C14:0) and palmitic (C16:0) acids. Cholesterol and vitamin E of plasma both doubled at the highest supplementation. Milk yield, solids-not-fat, protein and milk cholesterol were unaltered. Fat in feces doubled from about 3 to 6%. Daily linoleic acid content of feces increased from 25 g to 120 g, indicating a dietary loss of 7 to 10% of this polyunsaturated acid. These cheaper feed ingredients elevated the polyunsaturated fats in milk as effectively as the expensive purified casein and safflower oil supplements in previous experiments.     

Chloramphenicol antibody causing interference in antibody detection and identification tests

Investigation of the serum of three patients with positive antibody detection tests demonstrated the cause in each to be an antibody against chloramphenicol, a bacteriostatic agent used in commercial red blood cell reagents. Washing of these red cells prior to use prevented agglutination. All three examples of anti-chloramphenicol antibody were IgM and were in low titer when tested at room temperature and 37 C in saline. Two of the antibodies bound complement. The possibility of an antibody to an ingredient of the commercial preservative solution should be considered if problems are encountered in tests with unwashed commercial red blood cell reagents.     

Significance of a new type of human fetal hemoglobin carrying a replacement isoleucine replaced by threonine at position 75 )E 19) of the gamma chain

Mating speed of flies which have been aged either in the light, in the dark or in a light-and-dark cycle was measured using two strains, Rochester (R) and Salvador (S), of Drosophila mercatorum. A significant difference in mating tendency depending on the condition of pretreatment was found between R and S strains, while both strains showed a similar pattern of the diurnal rhythm in the light-and-dark cycle. Compared under the same conditions, S flies usually showed a higher mating speed than R flies. Mating speed seems to be affected by at least two different genetic systems. One of them is the genetic system determining absolute speed of mating. Another is the genetic system determining sensitivity to the environmental conditions. There may be considerable differentiation in both systems between R and S strains.