Biomedical subjects
Publications and source records attributed to D Durand.
Although the link between phosphate diabetes and neoplasm or benign mesenchymal tumors has been well documented, the nature of the phosphaturia factor remains unknown. We describe two cases of phosphate diabetes associated with bronchogenic cancer. In these case reports, we suggest that fibroblasts or osteoblasts synthesize a phosphate eliminating substance.
The ability of the fetal rat to respond to interleukin 1 beta (IL1 beta) by expressing alpha 1-acid glycoprotein (AGP) was investigated. Eight and 20 h after injection of 7 ng IL1 beta into 19-day fetuses, liver AGP mRNA increased by a factor of 66 and 82 respectively, while serum AGP levels increased by a factor of 3 and 5. Similar treatment of the mothers altered in the fetuses neither AGP serum levels nor the amount of liver AGP mRNA. The induction of AGP gene expression in the fetal liver in response to IL1 beta was similar to that observed in the adult liver. These results demonstrate that at day 19 the fetal rat liver has acquired a mature acute-phase system.
Rheological changes occurring during the gelation of low methoxy pectins in the presence of calcium ions were investigated. The onset of gelation was found to correspond to the same macroscopic rheology (i.e. value of G') whatever the gelling conditions. Sol-gel diagrams for calcium pectin systems were mapped out in terms of calcium level, temperature and pectin concentration. The thermodynamic parameters for the cross-linking process were derived.
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Developmental changes in hepatic growth hormone binding sites were examined in the genetically obese male fa/fa rats and in the lean littermates. At 16 days, fa/fa pups are normoinsulinemic; the specific binding of 125I-hGH to liver membranes is comparable in the two genotypes. At 4 weeks and later on, plasma membranes and Golgi fractions of male obese Zucker rats have more GH binding sites than lean littermates. The GH pituitary content is comparable in the two genotypes from 2 to 8 weeks and in 14-week-old fa/fa rats it is half that in lean animals. In the two genotypes plasma IGFI dramatically increases during puberty. At 4 weeks, plasma IGFI level is significantly higher in fa/fa rats than in lean littermates. In this model of genetic obesity, an increased GH binding to liver membranes is observed after the third week of life, shortly after the onset of hyperinsulinemia in the fa/fa rat.
Five preruminant calves, fitted with chronically indwelling catheters in the hepatic and portal veins and hepatic artery, were fed two kinds of diet (a conventional clotting milk diet and an incurdled milk diet) or fasted for 24 h. The statistical analysis of the plasma growth hormone (GH; nmol/l) or IGF1 (nmol/l) daily secretory profiles indicated that hormonal levels were very high in fed calves (GH mean values: 0.40 +/- 0.11 and 0.36 +/- 0.10, respectively; IGF1 mean values: 6.65 +/- 0.57 and 7.54 +/- 0.33, respectively). The GH secretory profile observed over a 24-hour period showed 7 secretory spikes without periodicity in both diets. In fasting animals, plasma GH and IGF1 concentrations were very low (0.17 +/- 0.08 and 3.08 +/- 0.36, respectively) and stable, they increased with refeeding (1.51 +/- 0.05 and 7.36 +/- 0.55, respectively). Hepatic IGF1 production (micrograms/kg body weight/day) was 195 +/- 7 in standard milk fed calves and -255 +/- 30 in others. Our results demonstrated that nutritional factors, such as different kinetics of gastric emptying or fasting, may influence hepatic IGF1 production in the conscious newborn calf.
We have studied the possible influence of steroid hormones and a beta-agonist (clembuterol) on hepatic insulin-like growth factor 1 (IGF1) production in young calves. For this purpose nine 20- to 40-day-old Holstein X Friesian male calves were fitted with chronically indwelling catheters in hepatic and portal veins and hepatic artery. Estradiol induced a simultaneous increase in plasma growth hormone (GH nmol/l) and IGF1 (nmol/l) levels (0.35 +/- 0.05 vs. 0.10 +/- 0.01 in control calves; 9.5 +/- 1.0 vs. 5.9 +/- 0.5 in controls, respectively). In the same way, 90 min after starting testosterone treatment, plasma GH levels increased from 0.21 +/- 0.08 to 1.30 +/- 0.40 while plasma IGF1 concentrations began to rise only 240 min after starting infusion (8.4 +/- 1.0) to reach maximal values at 300 min (10.7 +/- 1.1). Cortisol and clembuterol did not significantly modify either plasma GH levels or plasma IGF1 concentrations. Our results indicate that in young calves gonadal steroids exert their anabolic action through GH and IGF1.
Four young milk-fed calves were fitted with catheters chronically implanted in the mesenteric, portal and hepatic veins and in the hepatic artery, and with electromagnetic blood flow probes in the portal vein and hepatic artery, allowing continuous measurement of IGF-I hepatic production. According to a latin square design, these calves received iv mesenteric infusion of calcium (Ca2+; 5 mg/kg) or synthetic salmon calcitonin (sCT; 1 microgram/kg), or synthetic bovine parathyroid hormone (1-34) (bPTH; 1 microgram/kg), or solvent alone (1.2 ml/kg). Ca2+, sCT or bPTH had no significant effect on portal vein or hepatic artery blood flow. Hypercalcemia observed following Ca2+ infusion did not significantly modify hepatic IGF-I production. sCT decreased plasma Ca2+, inorganic phosphorus and GH concentrations and hepatic IGF-I production. bPTH induced a slight hypercalcemia and hypophosphatemia. It had no significant effect on plasma GH concentration, but increased significantly hepatic IGF-I production. Thus, the anabolic effects of PTH on bone may be partly mediated through an increase in hepatic IGF-I production.
The effects of dopamine on GH release were investigated both in vivo in freely moving intact rats and in rats with a mediobasal hypothalamic lesion, and in vitro in a perifusion system using dispersed male rat pituitary cells kept in primary culture. In vivo, dopamine (5 mg/kg body weight) induced a rapid and very transient increase in plasma GH levels in lesioned but not in intact rats. This increase was markedly inhibited by a prior injection of the D1 antagonist SCH 23390 (0.5 mg/kg) but not of the D2 antagonist domperidone (0.5 mg/kg). The D1 agonist SKF 38393 induced a dose-dependent stimulation of GH release in lesioned rats, and the effect obtained with a dose of 5 mg/kg was abolished by pretreatment with SCH 23390 (0.5 mg/kg). In vitro, dopamine (0.1 mumol/l) and SKF 38393 (0.1 mumol/l) provoked a rapid and reversible release of GH from superfused rat pituitary cells; this effect was markedly inhibited by simultaneous superfusion of SCH 23390 (1 mumol/l). These findings indicate that dopamine can stimulate basal GH release at the pituitary level and that this stimulation is mediated by D1 but not by D2 receptors. They also support the hypothesis that unidentified hypothalamic neurohormones may modulate this effect.
We have recently evaluated the in vivo role of the liver in lipoprotein homeostasis in the preruminant calf (Bauchart, D., D. Durand, P. M. Laplaud, P. Forgez, S. Goulinet, and M. J. Chapman, 1989. J. Lipid Res. 30: 1499-1514). We now present the partial characterization of lipoprotein particles in postprandial intestinal lymph at peak lipid absorption (i.e., 10 h after a meal) in the preruminant calf fed a curdled milk replacer. Intestinal lymph from four male preruminant calves was analyzed for its content of lipids and fractionated by sequential and density gradient ultracentrifugation into chylomicrons (Sf greater than 400), very low density lipoproteins (VLDL) (Sf less than 400; d less than 1.006 g/ml), and a series of lipoprotein subfractions with d greater than 1.006 g/ml. Postprandial lymph contained predominantly triglycerides (1099 +/- 611 mg/100 ml), with lesser amounts of phospholipids (197 +/- 107 mg/100 ml) and cholesterol (52 +/- 30 mg/100 ml). The most abundant particles were triglyceride-rich chylomicrons and VLDL which accounted for approximately 76% and approximately 19%, respectively, of total d less than 1.21 g/ml lipoproteins. As judged by negative stain electron microscopy, chylomicron particle diameters ranged from 650 to 2400 A, while VLDL were smaller and distributed over a distinct size range (340-860 A). These two lipoprotein classes each presented protein components with Mr comparable to those of human apoB-48, apoA-I, and C apoproteins, together with an Mr 52,000 protein resembling human beta 2-glycoprotein-I. In addition, VLDL exhibited a polypeptide with Mr approximately 61,000. Lymph lipoproteins with d greater than 1.006 g/ml consisted primarily (approximately 81% of total) of particles distributed over the 1.053-1.119 g/ml density range. Electrophoretic analysis of the latter lipoprotein fraction showed it to be heterogeneous, including particles with the migration characteristics of low and of high density lipoproteins, respectively. Subfractions in the d 1.053-1.076 g/ml range were dominated by particles with Stokes diameters typical of high density lipoproteins (HDL), but also contained three different populations of low density lipoprotein-like particles. The high molecular weight apolipoproteins in these same cholesteryl ester-rich (greater than 30% of lipoprotein mass) subfractions comprised components with Mr resembling those of human apoB-100 and apoB-48, respectively, and with the latter protein predominating to a varying degree. A counterpart to human apoA-I was the major protein component over the entire density range from d 1.053 to 1.119 g/ml.(ABSTRACT TRUNCATED AT 400 WORDS)
In the acceptance that, during early gonadogenesis, variations of germ cell (GC) proliferation express interactions between germ and somatic cells, early events occurring before histological differentiation of gonadal sex has been detected and timed through GC counts on larvae of Pleurodeles waltl (urodele amphibia) issued from male ZZ or female ZW monosexual offspring. Gonads differentiate in accordance with sexual genotype in ZZ and ZW larvae at room temperature and in ZZ larvae at 32 degrees C whereas they are sex-reversed at 32 degrees C in ZW larvae, becoming phenotypic neomales. At both the rearing temperatures, in genital ridges, GCs do not proliferate during a period called P0 period ending earlier in ZZ than in ZW larvae. The time when proliferation starts depends on sexual genotypes and determines a ZZP0 period shorter than ZWP0 period. After P0 period, at room temperature, a moderate increase in GC number determining a P1 period is observed in both ZZ and ZW larvae, whereas a strong proliferation, determining a P2 period, occurs on a differential pattern in ZZ and ZW larvae; thus, before sexual differentiation of gonads, ZW females have more GCs than ZZ males. At 32 degrees C, GC proliferation is moderate during P1 period and does not accelerate during P2 period in ZW larvae differentiating neotestes; they have a lower GC number than ZZ larvae reared at 32 degrees C. Thus, during P2 period, at both room temperature and at 32 degrees C, GC number correlates with future phenotype of gonads. Results suggest that differential molecular events arise during early gonadogenesis and that testes may differentiate in different ways according to whether phenotype conforms to genotype or sex reversion occurs.
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Hypercalcaemia is a frequent situation in clinical practice. An earlier detection is facilitated by routine analysis of serum calcium. The clinical manifestations depend on severity and the rate of onset of hypercalcaemia. Paucisymptomatic and asymptomatic presentations are the most frequent. Causes of hypercalcaemia are numerous and the mechanisms are various. PTH and vit. D play a preponderant part. In first of all iatrogenic cause are eliminated (all vit D preparations, thiazide diuretics, milk-alkali syndrome). Among non neoplastic hypercalcaemia primary hyperparathyroidism is the first diagnosis. Nephrolithiasis and asymptomatic forms are the most frequent presentations actually. The biochemical profile is not always typical. Generally the association of echography and tomodensitometry lead to the topographic diagnosis. Parathyroid surgical exploration is often necessary in difficult cases. Secondary, the other rare causes of hypercalcaemia are studied: sarcoidosis and granulomatosis disease, thyrotoxicosis and dome endocrinopathies, immobilisation hypercalcaemia, familial hypocalciuric, hypercalcaemia. All of this causes of hypercalcaemia are potentially reversible.
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Radiological exploration of the urinary tract has become highly sophisticated. The information provided by the new imaging techniques is extremely accurate and useful in the diagnosis and pretherapeutic assessment of most urinary tract diseases. Interventional radiology has given radiologists an important role in the treatment of some types of pathology. The authors describe the value of modern imaging and its different aspects in each of the principal branches of urinary tract pathology, viz.: tumours, obstructions, infections, vascular and prostatic diseases.
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