Normalization of serum calcium by cinacalcet in a patient with hypercalcaemia due to a de novo inactivating mutation of the calcium-sensing receptor

Familial benign hypocalciuric hypercalcaemia (FHH) results from a heterozygous inactivating mutation of the calcium-sensing receptor (CaR) and is characterized by hypercalcaemia, hypocalciuria and inappropriately normal plasma levels of parathyroid hormone. In a minority of patients, a loss of function mutation of the CaR results in severe hypercalcaemia associated with complications for which no effective surgical or medical treatment is available. We investigated the effects of the calcimimetic agent cinacalcet, an allosteric modulator of the CaR, in a 26-year-old man presenting with hypercalcaemia due to a de novo inactivating mutation of the CaR. Complicating features were recurrent psychosis and progressive severe osteoporosis. A single dose of either 30 or 60 mg of cinacalcet resulted in a 63-88% decline in plasma parathyroid hormone levels within 2 h of administration of the agent, reverting to baseline levels after 12 h. Normalization of serum calcium was more gradual but sustained for up to 12 months of treatment with a maintenance twice-daily oral dose of 60+30 mg cinacalcet. In addition to its beneficial effects in primary and secondary hyperparathyroidism, cinacalcet may open new therapeutic avenues in the management of a subset of patients with severe hypercalcaemia due to inactivating mutations of the CaR.     

In vitro interactions of PGE and cAMP with murine and human erythroid precursors

Addition of prostaglandins of the E series (PGE1, PGE2) in methylcellulose cultures of murine marrow results in a dose-dependent inhibition of the cloning efficiency of both BFU-E and CFU-C. However, CFU-E growth is unaffected. The inhibitory action of PGE is progressively overcome by increasing amounts of colony-stimulating factor (CSF), and with some limitations, also of erythropoietin (Ep). Addition of PGF2 alpha' associated or not with indomethacin, does not exert any significant effect on these hemopoietic precursors. In an attempt to unvail the mechanism(s) underlying these phenomena, dibutyryl-cyclic AMP (db-cAMP), theophylline (an inhibitor of phosphodiesterase), or theophylline + PGE were plated at various concentrations. Both db-cAMP and theophylline induce an inhibitory influence on both BFU-E and CFU-C growth, which mimicks that by PGEs; additionally, theophylline potentiates the inhibitory action of PGE1. In all these studies, the CFU-E number was not significantly modified. PGE action on BFU-E proliferation is clearly species-dependent, since PGE1 addition to human marrow methylcellulose cultures induces a significant enhancement of the number of both BFU-E and CFU-E derived colonies. This action was abolished upon removal of adherent cells, thus suggesting that PGE1 evokes a release of factor(s) enhancing human erythroid colony growth by adherent cells.     

Progressive histopathological changes in pancreatic islets of Zucker Diabetic Fatty rats.

Thus far, histopathological changes in the pancreatic islets of Zucker Diabetic Fatty (ZDF) rats, an animal model of type 2 diabetes mellitus (or non-insulin-dependent diabetes mellitus), have only been studied in male rats and in 18-weeks old rats or younger. In this study, we have examined in both male and female ZDF rats the histopathological changes longitudinally, from 6 to 32 weeks of age. We studied islet architecture and cellular distribution of the various islet hormones both in ZDF and control rats. In the ZDF rats, aging was initially associated with an enlargement of the islets. From 18 weeks onwards, no further enlargement was noted but islet boundaries became increasingly irregular, leading to the appearance of projections of endocrine cells into the surrounding exocrine tissue. At the islet boundaries as well as within the islets progressive fibrosis was observed with increasing amounts of collagen and reticular fibers. In the islets, staining intensity of both insulin and islet amyloid polypeptide (IAPP) increased slightly till 10 weeks of age and thereafter decreased rapidly. In contrast, the staining intensities of glucagon, somatostatin, and pancreatic polypeptide (PP) did not change. Even at the age of 32 weeks, just the beta-cells and not the other endocrine islet cells appear to be affected. In control rats, aging evoked only minor changes. Thus, we observed that during prolonged development of diabetes mellitus in both male and female ZDF rats histopathological changes in the pancreatic islets became progressively more severe, eventually leading to disintegration of the islets.     

Expression of phosphorylcholine-specific B cells during murine development

The TEPC 15 (T15) clonotype, a putatively germline antibody specificity, does not appear in the neonatal B-cell repertoire until approximately 1 wk of age. This report extends this observation by the demonstration that (a) the T15 clonotype follows similar kinetics of appearance in germfree as well as conventionally-reared mice; (b) maternal influences and genetic background play a minor role in the development of the T15 clonotype since CBFI neonates raised by C57BL/6 or BALB/c mothers acquire the T15 clonotype at the same time in ontogeny as BALB/c neonates; (c) the lack of phosphorylcholine (PC)-specific B cells shortly after birth is reflected in a dearth of PC-binding cells in the neonate as well; and (d) no PC-specifc B cells are found in 19-day fetal liver or in bone marrow until 7 days of life, coincident with their appearance in the spleen. These findings, along with a previous report that PC-specific splenic B cells are tolerizable as late as day 10 after birth, confirm the invariant, late occurrence of the T15 clonotype and support a highly- ordered, rigorously predetermined mechanism for the acquisition of the B- cell repertoire. The results are discussed in light of other studies on the ontogeny of B-cell specificity, and in terms of the implications on the mechanism by which antibody diversity is generated.     

The coagulant-active phospholipid content is a major determinant of in vivo thrombogenicity of prothrombin complex (Factor IX) concentrates in rabbits

In vitro evaluation of prothrombin complex concentrates in a thrombin generation assay, using DAPA and purified components of the prothrombinase complex, demonstrated significant levels of coagulant- active "phospholipid replacing" activity. Quantification of this activity showed a significant correlation (r = 0.8747, p less than 0.01) with thrombogenicity measured in vivo in a stasis model in rabbits. Extracted lipid material retained full phospholipid replacing activity in the vitro assay. Thin-layer chromatographic characterization confirmed the presence of phospholipids with known coagulant activity in vitro. In vivo, the extracted material was nonthrombogenic but augmented the thrombogenicity of purified factor Xa. Substitution of a synthetic coagulant-active phospholipid (phosphatidylcholine-phosphatidylserine lipid vesicles) for the extracted phospholipid produced a similar augmentation of a factor-Xa- induced thrombogenicity in vivo. It is concluded that the coagulant- active phospholipid content of prothrombin complex concentrates is a major determinant of thrombogenicity but requires the presence of activated clotting factors for its expression in vivo.     

Normal bone mineral density and lean body mass,but increased fat mass,in young adult patients with congenital adrenal hyperplasia

Patients with congenital adrenal hyperplasia attributable to 21-hydroxylase deficiency are treated with glucocorticoids. Glucocorticoid administration, even in substitution doses, may cause decreased bone mineral density (BMD) and obesity. The purpose of this study was to determine BMD, lean mass, and fat mass in young adult male (M, n = 15) and female (F, n = 15) patients with 21-hydroxylase deficiency, who had been treated with currently recommended low doses of glucocorticoids. Measurements were performed with dual-x-ray absorptiometry. In addition, calcaneal ultrasound measurements were performed (broadband ultrasound attenuation and speed of sound). Results were compared with those in age- and sex-matched controls; to adjust for height, lean and fat mass were divided by (height)(2). M and F patients [M, 21.7 +/- 2.4; F, 20.6 +/- 2.9 yr old (mean +/- SD)] were shorter than the controls (M, P < 0.001; F, P < 0.003) and their body mass indices were higher [M patients (25.0 +/- 3.6) vs. controls (22.3 +/- 1.9 kg/m(2)) (P < 0.02); F patients (25.5 +/- 4.5) vs. controls (21.9 +/- 2.3 kg/m(2)) (P < 0.02)]. BMD values (lumbar spine L1-L4, femoral neck, and total body) were not different from controls. Calcaneal ultrasound measurements showed that M patients had higher speed of sound values [M patients (1564 +/- 38) vs. controls (1529 +/- 29 m/sec) (P < 0.01)]. Lean mass in M and F patients was not different from controls when adjusted for height. Fat mass was higher in M and F patients when adjusted for height [M patients 5.6 +/- 2.9 vs. controls 2.7 median (1.7-7.0 min-max) kg/m(2) (P < 0.04); F patients 8.7 +/- 2.8 vs. controls 5.8 (4.3-10.7) kg/m(2) (P < 0.02)]. Relative fat mass (fat mass as a percentage of the total body mass) was higher in patients, compared with controls [M patients 22.0 +/- 9.1 vs. controls 12.8 (8.5-27.0)% (P < 0.04); F patients 34.1 +/- 5.0 vs. controls 29.0 +/- 5.1% (P < 0.02)]; this resulted from increased fat mass, not from decreased lean mass. Fat distribution over the body was not different in patients and controls. No significant correlations were found between cumulative glucocorticoid doses in the last 0.5, 2, or 5 yr or mean salivary morning levels of 17-hydroxyprogesterone and androstenedione in the last 5 yr on one hand and bone parameters, lean mass, or fat mass on the other hand. We conclude that, at prevailing low-dose glucocorticoid regimens, young adult patients with 21-hydroxylase deficiency have normal BMD. Their lean mass is in accordance with height, but fat mass is increased, with a normal distribution over the body. This results in a higher fat percentage of the total body and a higher body mass index than in healthy peers. Because overweight and increased fat mass are associated with the metabolic syndrome and increased cardiovascular risk, weight management should have appropriate attention in the follow-up of congenital adrenal hyperplasia patients, to prevent overweight-associated morbidity.