Melatonin Inhibits GnRH-Induced Increase of cFOS Immunoreactivity in Neonatal Rat Pituitary

In neonatal rat gonadotrophs, melatonin inhibits several GnRH-induced effects: stimulation of LH release as well as the increase of several second messengers as cAMP, diacylglycerol and [ Ca²⁺]_i . Recently, GnRH has been shown to induce expression of immediate early genes of fos and jun family in adult rat gonadotrophs. The purpose of this study was to determine, whether melatonin inhibits the GnRH-induced induction of cFos in neonatal rat pituitary cells.     

Drug analysis with polarographic methods. 33. Electroanalytic studies of a new benzodiazepine: [6(o-chlorophenyl)-2,4-dihydro-2-[(4-methyl-1-piperazinyl) methylene]-8-nitro-1H-imidazol[1,2-a][1,4]benzodiazepine-1-one (WHO) (loprazolam,1)] and content determination its drug forms

Loprazolam (1) is a tricyclic benzodiazepine containing a new butazadiene moiety, which has not been investigated by polarography up to now. 1 is reduced in three waves at a DME over the whole pH-region. In BRP (pH 2-9) 10 electrons are consumed in this process. The first step is suitable for the determination of 1 in Loprazolam tablets containing 1 or 2 mg. These tablets are on the pharmaceutical market in several European countries. The mechanism of the electrode process will be reported in the communication XXXIV.     

Neuropeptide Y in the female reproductive tract of the rat. Distribution of nerve fibres and motor effects

The spontaneous firing of single neurones in the region of the lateral reticular nucleus was the subject of a pharmacological study employing microiontophoretic and systemic application of adrenoceptor agonists and antagonists. Both iontophoretic noradrenaline and systemic clonidine depressed neuronal firing. The depressions were consistently reversed by the alpha-2 antagonist RX781094. Other adrenergic antagonists, prazosin and sotalol, were ineffective. The results suggest the existence of alpha-2 receptors in this region of the brain.     

The FAD-containing monooxygenase-catalyzed N-oxidation and demethylation of trimethylamine in rat liver microsomes

Trimethylaminuria (TMAuria), the excessive urinary excretion of the odorous trimethylamine (TMA), accompanies elimination of TMA in sweat and corresponding "fish-odor" syndrome. TMA was oxidized in vitro in rat liver microsomes from male Sprague-Dawley rats to TMA N-oxide and N-demethylated to dimethylamine (DMA). Both reactions were inhibited to 1-3% of normal activity by preincubation of microsomes without NADPH-generating system at 37 degrees C for 10 minutes indicating the FAD-containing monooxygenase-catalyzed reactions. On the other hand, the reactions were not inhibited by gas phase containing up to 80% carbon monoxide/20% oxygen mixture. The results are compatible with the hypothesis that in rat liver microsomes the N-oxygenation and N-demethylation of TMA are catalyzed only or predominantly by FAD-containing monooxygenases, and the cytochrome P-450 monooxygenases play a negligible, if any, role.     

Hybridization of the 18 alpha-satellite probe to chromosome 1 revealed in PGD

Although the chromosome 18 alpha-satellite probe is considered to have a very low polymorphism rate, the routine use of this probe in prenatal diagnosis revealed rare variants in size and copy number of these sequences. A polymorphic signal was detected in preimplantation genetic diagnosis (PGD) for aneuploidy, in a patient with repeated early miscarriages. A third small signal of chromosome 18 alpha-satellite probe was observed in two of four evaluated embryos. Hybridization to the woman's metaphasic lymphocytes revealed that the small signal was localized in the pericentromeric region of chromosome 1. Reanalysis of blastomeres with telomeric probes for chromosome 18q confirmed the presence of only two copies of chromosome 18. Options for verifying PGD analysis results, to prevent misdiagnosis in cases of suspected polymorphism, are discussed. Although some authors speculate about a possible role of heterochromatin polymorphism in infertility, this rare polymorphism of 18 alpha-satellite sequences is in itself probably a normal variant. This is the third report of a cross-hybridization of the chromosome 18 alpha-satellite probe and the first report of the localization of the polymorphic 18 alpha-satellite signal to chromosome 1.     

Aberrant IgA1 glycosylation is inherited in familial and sporadic IgA nephropathy

IgA nephropathy (IgAN) is a complex trait determined by genetic and environmental factors. Most IgAN patients exhibit a characteristic undergalactosylation of the O-glycans of the IgA1 hinge region, which promotes formation and glomerular deposition of immune complexes. It is not known whether this aberrant glycosylation is the result of an acquired or inherited defect, or whether the presence of aberrant IgA1 glycoforms alone can produce IgAN. A newly validated lectin enzyme-linked immunosorbent assay (ELISA) was used to determine the serum level of galactose-deficient IgA1 (Gd-IgA1) in a cohort of 89 IgAN patients and 266 of their relatives. High Gd-IgA1 levels (> or =95th percentile for controls) were observed in all 5 available patients with familial IgAN, in 21 of 45 (47%) of their at-risk relatives (assuming autosomal dominant inheritance), and in only 1 of 19 (5%) of unrelated individuals who married into the family. This provides evidence that abnormal IgA1 glycosylation is an inherited rather than acquired trait. Similarly, Gd-IgA1 levels were high in 65 of 84 (78%) patients with sporadic IgAN and in 50 of 202 (25%) blood relatives. Heritability of Gd-IgA1 was estimated at 0.54 (P = 0.0001), and segregation analysis suggested the presence of a major dominant gene on a polygenic background. Because most relatives with abnormal IgA1 glycoforms were asymptomatic, additional cofactors must be required for IgAN to develop. The fact that abnormal IgA1 glycosylation clusters in most but not all families suggests that measuring Gd-IgA1 may help distinguish patients with different pathogenic mechanisms of disease.     

Hidradenoma papilliferum with oxyphilic metaplasia: a clinicopathological study of 18 cases, including detection of human papillomavirus

Reported here are 18 cases of hidradenoma papilliferum with oxyphilic metaplasia. All patients were women ranging in age from 29 to 74 years. Each presented clinically with a small, solitary tumor in the anogenital region. Microscopically, in addition to classic histopathological features, in every case there was oxyphilic metaplasia of the constituent epithelial cells. This finding could be likened to apocrine metaplasia, a term used in breast pathology. Other histopathological findings observed in this series, analogous to benign breast disease, included sclerosing adenosis-like changes, atypical apocrine adenosis-like changes, changes corresponding to usual ductal epithelial hyperplasia, epitheliomatosis with a streaming growth pattern, lamprocyte-like changes, clear cell change of the myoepithelium, foamy histiocyte reaction, and stromal fibrosis. Immunohistochemistry inferred that in the majority of cases oxyphilic metaplasia resulted from more lysosomes, whereas numerous mitochondria were detected in only 3 cases. Using 2 different PCR methods we identified HPV in 4 of 15 cases of hidradenoma with oxyphilic metaplasia. In addition, HPV was detected in 3 of 16 conventional papillary hidradenomas used as a control group. The following HPV types were identified: 16, 31, 33, 53, and 56. The last type was found in 5 cases. More than one HPV type from a single lesion was seen in 5 cases. Our observations are consistent with previous publications noting similarities between tumors of the breast and sweat glands. Oxyphilic metaplasia, areas with solid growth, and changes simulating atypical apocrine adenosis are rare and poorly recognized in hidradenoma papilliferum and may cause diagnostic difficulties; in our cases several submitting pathologists suspected malignancy. A causal role for HPV in hidradenoma papilliferum cannot be confirmed from our results, as the detection rate is too low. The exact role of the HPV in etiology and pathogenesis of this neoplasm has yet to be determined.     

Trio engagement via plasma membrane phospholipids and the myristoyl moiety governs HIV-1 matrix binding to bilayers

Localization of the HIV type-1 (HIV-1) Gag protein on the plasma membrane (PM) for virus assembly is mediated by specific interactions between the N-terminal myristoylated matrix (MA) domain and phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P₂]. The PM bilayer is highly asymmetric, and this asymmetry is considered crucial in cell function. In a typical mammalian cell, the inner leaflet of the PM is enriched in phosphatidylserine (PS) and phosphatidylethanolamine (PE) and contains minor populations of phosphatidylcholine (PC) and PI(4,5)P₂. There is strong evidence that efficient binding of HIV-1 Gag to membranes is sensitive not only to lipid composition and net negative charge, but also to the hydrophobic character of the acyl chains. Here, we show that PS, PE, and PC interact directly with MA via a region that is distinct from the PI(4,5)P₂ binding site. Our NMR data also show that the myristoyl group is readily exposed when MA is bound to micelles or bicelles. Strikingly, our structural data reveal a unique binding mode by which the 2′-acyl chain of PS, PE, and PC lipids is buried in a hydrophobic pocket whereas the 1′-acyl chain is exposed. Sphingomyelin, a major lipid localized exclusively on the outer layer of the PM, does not bind to MA. Our findings led us to propose a trio engagement model by which HIV-1 Gag is anchored to the PM via the 1′-acyl chains of PI(4,5)P₂ and PS/PE/PC and the myristoyl group, which collectively bracket a basic patch projecting toward the polar leaflet of the membrane.     

Association of genetic variability in selected regions in visfatin (NAMPT) gene with anthropometric parameters and dietary composition in obese and non-obese Central-European population

AimsVisfatin (NAMPT/PBEF) is a recently identified adipocytokine which harbors strong insulin-mimetic activity and was reported to be associated with obesity. However, nothing is known about whether visfatin is related to specific nutritional behavior which may result in obesity development. This is the first study focusing on genetic variability of the visfatin gene and its association with circulating visfatin, anthropometric parameters and dietary composition.Materials and MethodsWe analyzed a total of 11 exons and adjacent non-coding regions of the NAMPT gene in 20 extremely obese Czech individuals (mean BMI 52.2 ± 5.0 SD) using direct sequencing and a frequency of rs2302559 was established in the validation cohort of another 605 individuals with completed 7-day food records and complex anthropometric measurements. Serum levels of visfatin, leptin and leptin-receptor were measured in all sequenced individuals and in part of the validation cohort.ResultsThree common polymorphisms were identified, two in non-coding regions (rs78411774 A/C, rs71564769 A/C) and one synonymous SNP in exon 7 (rs2302559 A/G). The rs2302559 showed significant correlation with visfatin serum level throughout the entire study cohort (p < 0.001); there was a significant tendency toward higher visfatin levels in G allele carriers with GG homozygotes having the highest visfatin serum levels. Furthermore, a negative correlation was observed between visfatin and leptin serum level (p = 0.01). No association between investigated SNPs and anthropometric parameters or native dietary composition was observed.ConclusionThis is the first study to demonstrate that the rs2302559 polymorphism in the PBEF gene is related to circulating levels of visfatin. As the SNP is synonymous, we hypothesize it might be linked to another SNP in the PBEF gene which controls visfatin serum levels.