The action of various vitamin D3 metabolites on calcium and phosphorus metabolism in chick embryo calvariae

Summary Chick embryos from vitamin D-deficient hens given physiological doses of 1,25-dihydroxyvitamin D₃ or 24,25-dihydroxyvitamin D₃ or both become severely hypocalcemic, hyperphosphatemic and fail to hatch as compared to those derived from hens given 25-hydroxyvitamin D₃ or 24,25-difluoro-25-hydroxyvitamin D₃. Calvariae from the former contain less mineral and on incubation in vitro produce significantly lower calcium and higher phosphate concentration in the medium than do the calvariae derived from the embryos of hens supported on 25-hydroxyvitamin D₃ or 24,24-difluoro-25-hydroxyvitamin D₃.     

Cadmium-induced changes in renal hemodynamics in the domestic fowl

Low i.v. doses of cadmium chloride (15 micrograms Cd) given to pullets resulted in a significant reduction in urine flow (UF), glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). However, in hens treated with the heavy metal chelate FeNa EDTA prior to cadmium treatment no oliguria or reduction in GFR or ERPF was observed. It is suggested that the renal changes following the i.v. administration of cadmium to diuretic hens and alleviated in hens primed with the heavy metal chelate may result from changes in glomerular hemodynamics.     

Cadmium-induced changes in renal hemodynamics in the domestic fowl

Summary Low i.v. doses of cadmium chloride (15 g Cd) given to pullets resulted in a significant reduction in urine flow (UF), glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). However, in hens treated with the heavy metal chelate FeNa EDTA prior to cadmium treatment no oliguria or reduction in GFR or ERPF was observed.It is suggested that the renal changes following the i. v. administration of cadmium to diuretic hens and alleviated in hens primed with the heavy metal chelate may result from changes in glomerular hemodynamics.     

Vitamin D receptors in heart: effects on atrial natriuretic factor.

We report that receptors for vitamin D exist in distinct regions of the heart in female and male mice, predominantly in the right atrium where most of the cardial atrial natriuretic peptide (ANF) is produced. Tritiated 1,25-dihydroxyvitamin D3 (1,25-D3, vitamin D, soltriol) and ANF are colocalized in nuclei and cytoplasm respectively in identical cardiomyocytes. Changes of ANF tissue and blood levels under dietary deficiency and treatment with 1,25-D3 suggest direct genomic actions of vitamin D on myoendocrine cells of the atrium for the regulation of ANF manufacture and secretion. These results were obtained by combining thaw-mount autoradiography with immunocytochemistry using tritiated 1,25-D3 and an antibody against rat ANF. This antibody was also used in a radioimmunoassay to determine atrial natriuretic factor in plasma, atria and ventricles of normal or vitamin D-deficient mice.     

Vitamin D receptors in heart: Effects on atrial natiuretic factor

We report that receptors for vitamin D exist in distinct regions of the heart in female and male mice, predominantly in the right atrium where most of the cardial atrial natriuretic peptide (ANF) is produced. Tritiated 1,25-dihydroxyvitamin D₃ (1,25-D₃, vitamin D, soltriol) and ANF are colocalized in nuclei and cytoplasm respectively in identical cardiomyocytes. Changes of ANF tissue and blood levels under dietary deficiency and treatment with 1,25-D₃ suggest direct genomic actions of vitamin D on myoendocrine cells of the atrium for the regulation of ANF manufacture and secretion. These results were obtained by combining thaw-mount autoradiography with immunocytochemistry using tritiated 1,25-D₃ and an antibody against rat ANF. This antibody was also used in a radioimmunoassay to determine atrial natriuretic factor in plasma, atria and ventricles of normal or vitamin D-deficient mice.     

单目视频运动目标轨迹三维重建的平滑约束法

提出了利用单目视频重建运动目标三维轨迹的平滑约束方法.通过引入平滑约束,得到重建运动目标三维轨迹的无约束最优化模型,进而推导出其闭式最优解.提出的平滑约束是对运动目标三维轨迹的本质约束,更具一般性,可以反映目标运动的连续、渐变与平滑特性,与基于离散余弦变换基和多项式基等预先定义基约束相比具有更强的适应性,同时能够直接应用于部分观测数据缺失的情形.给出了单目视频轨迹重建问题的几何解释,并对轨迹重建问题中的唯一性进行分析.仿真和真实单目视频序列上的实验证明了提出方法的有效性和先进性.     

Reproductive consequences of mega vitamin E supplements in female rats

Summary Female rats fed 0, 25, 2500 and 10,000 IU vitamin E/kg diet for 3 months were examined for reproductive performance. On 10,000 IU vitamin E/kg diet, the fertility of inseminated rats was significantly reduced as compared to rats given normal or nutritional levels of vitamin E.This work was supported by research grants from the National Research Council of Canada and the Research Committee of The University of British Columbia. We thank Mrs Virginia Green for her help in statistical analysis. Reprint requests should be addressed to Dr I. D. Desai, Professor of Nutrition.     

Invertébrés marins du lagon néo-calédonien. I. Étude structurale d'une nouvelle sapogénine extraite d'une holothurie:Bohadschia vitiensis Semper

Summary Acid hydrolysis of Cuvier's organs alkoholic extract of sea- cucumber,Bohadschia vitiensis, led to many sapogenins. The first 3 isolated compounds had already been isolated from another sea-cucumber species/seychellogenin, 22,25-oxido-holothurinogenin and 24,25-dehydro holothurinogenin. The 4th product is a new sapogenin formulated,4, on the basis of spectroscopic data.     

The role of parathyroid hormone and calcitonin in magnesium absorption in the rat small intestine

Summary We studied duodenal and ileal magnesium (Mg) absorption in intact, parathyroidectomized (PTX), thyroid-(TX) and thyroparathyroidectomized (TPTX) rats with iodine hormones replaced, and, additionally, in PTX rats receiving bovine parathyroid hormone 1–34 and 1,25-dihydroxyvitamin D₃, respectively. Ma absorption was reduced after PTX and TPTX in the duodenum, but not in the ileum, whereas TX had no influence on duodenal or ileal Mg absorption. Both bovine parathyroid hormone 1–34 and 1,25-dihydroxyvitamin D₃ increased Mg absorption in the duodenum and the ileum in PTX rats.Acknowledgments. We are grateful to B. Schreiber, K. Schwille and I. Goldberg for technical and secretarial help. Supported by Deutsche Forschungsgemeinschaft (Schw 210/3). Reprint requests to P.O.S., University Hospital, Maximiliansplatz, D-8520 Erlangen.     

Accumulation of Phosvel in adipose tissue of hens.

Phosvel, an organophosphorus pesticide, was stored in the adipose tissue of hens after they were given daily a single oral dose. The concentration of Phosvel in fat was related to the size of the daily dose.     

Inhibitory action of estradiol on testosterone production in rat embryo]

Embryos from Rats given an injection of 0,5-1 mg of oestradiol benzoate on days 17--19 of pregnancy show a 3--4-fold reduction in their testicular testosterone content with respect to the control embryos, 24--48 hrs later. OEstradiol most likely acts by inhibiting LH secretion, which in turn results in a lowered testosterone production.     

A comparative study of the differentiation of dissociated nerve cells under different culture conditions.

In vitro differentiation of chick embryo brain cells was compared under several culture conditions. Morphological observations and acetylcholinesterase histochemical staining revealed that the development was similar in all conditions tested if cells have been derived from 7 days embryos. Considering the cultures from 11 days embryos, the cell dissociation by trypsin and the plastic surface proved to be the most favourable conditions in contrast to mechanical dissection and collagen surface.     

Production of antibodies against bradykinin.

High-titer antibodies against bradykinin were raised in rabbits. 2 different conjugates of bradykinin were used for immunization: bradykinin coupled to human serum albumin via 1,5-difluoro-2,4-dinitrobenzene and bradykinin coupled to edestin via 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide. The sensitivity of the radioimmunoassay method is in the range of 1-50 pg of bradykinin. Cross-reaction of anti-bradykinin antisera occurred with kallidin and met-lys-bradykinin.     

Production of antibodies against bradykinin

Summary High-titer antibodies against bradykinin were raised in rabbits. 2 different conjugates of bradykinin were used for immunization: bradykinin coupled to human serum albumin via 1,5-difluoro-2,4-dinitrobenzene and bradykinin coupled to edestin via 1-ethyl-3(3-dimethyl-aminopropyl)-carbodiimide. The sensitivity of the radioimmunoassay method is in the range of 1–50 pg of bradykinin. Cross-reaction of anti-bradykinin antisera occurred with kallidin and met-lysbradykinin.     

Antifertilityeffects of clonidine in laying hens

Summary Clonidine was anovulatory and markedly antigonadal in laying hens when infused for 1 week from minipump implants at daily rates of 1.08 mg per hen or greater. The ovaries of hens treated with clonidine responded to FSH injections which suggests that the antigonadal effect of clonidine resulted from a reduction in the output of gonadotropin by the pituitary. These data suggest that ₂ receptors may be important in regulating avian fertility.     

The effect of 5-bromodeoxyuridine on mouse embryos during neurulation in vitro

Summary Mouse embryos explanted at various stages during neurulation were cultured for 20–28 h in the presence of 25–900 g/ml of 5-bromodeoxyuridine (BUdR). BUdR strongly inhibited closure of the cranial neural tube, which was found to be stage-dependent. When mouse embryos were exposed to BUdR after development of the concave curvature in the neuroepithelium of the midbrain to the upper hindbrain regions, they became insensitive to the drug-induced open cranial neural tube. Histological observations showed that BUdR interfered with interkinetic migration and cytokinesis of the neuroepithelial cells. These cellular abnormalities were not dependent on the morphological development of the cranial neural folds. The³H-BUdR experiment confirmed that the label was mostly incorporated into the DNA fraction.Acknowledgment. This work was supported by Grant-in-Aids for scientific research No. 557469 and 58480391 from the Ministry of Education, Japan.     

A comparative study of the differentiation of dissociated nerve cells under different culture conditions

Summary In vitro differentiation of chick embryo brain cells was compared under several culture conditions. Morphological observations and acetylcholinesterase histochemical staining revealed that the development was similar in all conditions tested if cells have been derived from 7 days embryos. Considering the cultures from 11 days embryos, the cell dissociation by trypsin and the plastic surface proved to be the most favourable conditions in contrast to mechanical dissection and collagen surface.M. Sensenbrenner is Maitre de Recherche au CNRS.     

Lack of influence of vitamin D deficiency on insulin release from the isolated pancreatic islets of rats

Pancreatic islets were isolated from young (100 g) and adult (390 g), normal and vitamin D deficient male Sprague-Dawley rats. The release of insulin from leucine-stimulated or glucose-stimulated islet was not altered by vitamin D deficiency. The in vitro addition of either 25-hydroxy- or 1,25-dihydroxyvitamin-D had no effect on insulin release from either normal or vitamin D deficient islets. We conclude that the earlier report (Normal et al., Science 209 (1980) 823-825) on vitamin D deficiency depressing insulin secretion from the perfused pancreas must be related to the vitamin's effect on insulin synthesis and not the islet's release of insulin.     

The effect of 5-bromodeoxyuridine on mouse embryos during neurulation in vitro

Mouse embryos explanted at various stages during neurulation were cultured for 20-28 h in the presence of 25-900 micrograms/ml of 5-bromodeoxyuridine (BUdR). BUdR strongly inhibited closure of the cranial neural tube, which was found to be stage-dependent. When mouse embryos were exposed to BUdR after development of the concave curvature in the neuroepithelium of the midbrain to the upper hindbrain regions, they became insensitive to the drug-induced open cranial neural tube. Histological observations showed that BUdR interfered with interkinetic migration and cytokinesis of the neuroepithelial cells. These cellular abnormalities were not dependent on the morphological development of the cranial neural folds. The 3H-BUdR experiment confirmed that the label was mostly incorporated into the DNA fraction.