On the structure of Ge/GeO2 glasses.

Germanium-Germanium bonds or atomic germanium are unlikely to be present in germanium dioxide glasses containing excess germanium.

UNDP initiates MicroStart in Egypt to alleviate poverty.

PIP: The UN Development Program, in alliance with Egypt's Social Fund for Development, has agreed to pilot a MicroStart project under its Job Creation Programme as a means to promote income generation among the poor. This project aims to improve access in appropriating financial services offered by local organizations to the economically active poor in order to enhance their economic activities. The success to date has been limited and outreach to women is often restricted to special women-only projects, although some organizations have experimented with solidarity group lending in Egypt. In achieving a major objective of MicroStart in Egypt, it will be necessary to detect the compatibility of group lending methodologies in Egypt as well as to examine other appropriate mechanisms for increasing outreach to women.^ieng

Excretion and metabolism of tipredane, a novel glucocorticoid, in the rat, mouse, monkey, and human.

The excretion and metabolism of [3H]tipredane, a novel glucocorticoid, has been studied in mice, rats, marmosets, rhesus and cynomolgus monkeys, and humans. After oral administration, [3H]tipredane was rapidly absorbed, metabolized, and excreted into urine and feces. In mice and male rats, radioactivity was excreted primarily into feces or bile, whereas in female rats, monkeys, and humans, excretion was mainly via the renal route. Some sex differences in the proportions excreted into urine and feces were noted in rodents, with females eliminating relatively more radioactivity in urine. Tipredane was shown to be extensively metabolized, but the routes were highly species-dependent and, in the rat, they were sex-dependent. Unchanged tipredane was not detected in any urine, bile, or blood extracts. Urinary and blood extract profiles indicated that there were between 10 and 30 metabolites in rats and mice, the majority of which constituted < 2% of the dose. In these species, the major pathways involved loss of the thioethyl moiety, S-oxidation of the thiomethyl group, and saturation of the adjacent saturated C16-17 bond. Hydroxylation of the steroid B-ring was seen in the 7 alpha-position in mice and female rats, and in the 6 beta-position in male rats. Metabolism of tipredane in rhesus and cynomolgus monkeys and humans was similar, but less extensive and different to that seen in rodents. The major products, the 6 beta-hydroxylated sulfoxide and sulfone metabolites of tipredane, accounted for 21-36% of the dose in human and monkey urine, and were also major components in blood. In contrast to mice and rats, S-oxidation and an unsaturated C16-17 bond were evident in primates. Metabolism of tipredane was rapid and complex, with significant species differences, although the disposition in rhesus and cynomolgus monkeys seemed to be similar to humans.

Vapor Phase Vibrational Spectra for Re(2)O(7) and the Infrared Spectrum of Gaseous HReO(4). Molecular Shapes of Mn(2)O(7), Tc(2)O(7), and Re(2)O(7).

The Raman and infrared spectra of gas phase Re(2)O(7) are reported. The experimental vibrational spectra of molecular Tc(2)O(7) and Re(2)O(7) are compared with calculated spectra. The results of these studies agree with a nonlinear M-O-M bridge for Tc(2)O(7) and Re(2)O(7). For infrared intensity calculations, the point charge approximation is used, while for the Raman calculations a combination of bond and atom polarizabilities is adopted. Pure Re(2)O(7) was prepared from rhenium wire, but attempts to prepare it from rhenium powder and oxygen always led to infrared spectra showing serious contamination from a species containing an -OH linkage. Detailed experiments identified this molecule as HReO(4), a unique transition metal analogue of the perhalic acids, and a partial infrared spectrum of this molecule is reported.

Cloning and characterization of T-cell-reactive protein antigens from Listeria monocytogenes.

To explore the molecular basis of the T-cell-mediated immune response to Listeria monocytogenes, we cloned and expressed listerial antigens in Escherichia coli using the lambda-ZAP bacteriophage and Bluescript plasmid vectors. A two-stage screening strategy was implemented to identify T-cell-reactive antigens; the first stage involved antibodies or oligonucleotide probes and the second stage was based on assays for T-cell activation. A library of genomic DNA from L. monocytogenes was generated in lambda-ZAP, and then antigens, were detected in infected cells with a polyclonal rabbit anti-L. monocytogenes antiserum and an L. monocytogenes-specific monoclonal antibody. Also, synthetic oligonucleotide probes corresponding to the structural gene for listeriolysin O (LLO) were used to screen the recombinant DNA library. In each case, positive isolates were evaluated for T-cell antigenicity by measuring antigen-induced interleukin-2 production by polyclonal T cells taken from L. monocytogenes-immune mice. Phage clones were subcloned and expressed in the Bluescript plasmid and tested further for antigenic activity and LLO expression. Using this screening strategy, we successfully identified bacterial clones producing recombinant listerial antigens which activate L. monocytogenes-immune T cells in vitro. Antigens operative in the T-cell response during infection with L. monocytogenes include LLO, 62- and 39-kilodalton proteins, and other poorly defined bacterial surface components. We also found that high concentrations of recombinant LLO inhibited macrophage-mediated antigen presentation. These results are discussed in terms of the multiple functions of LLO as a virulence factor, inhibitor of antigen presentation, and potent antigen in the T-cell response to L. monocytogenes. These studies represent the first step toward a genetic definition of the antigens recognized in immune defense to L. monocytogenes.

Metabolism of temelastine (SK&F 93944) in hepatocytes from rat, dog, cynomolgus monkey and man.

A species comparison of the metabolic pathways of temelastine has been made using hepatocyte preparations from rat, dog, cynomolgus monkey, and man. Metabolites and unchanged temelastine were separated by HPLC and were compared with authentic standards by retention. The characteristic UV spectra of SK&F 93944 and its metabolites aided in the preliminary identification of metabolites in hepatocyte incubates, subsequently confirmed by liquid chromatography/mass spectrometry (LC/MS). The metabolic profile of temelastine is complex, both in vivo and in vitro, but all of the metabolites identified unambiguously from in vivo studies have also been demonstrated in vitro. Moreover, the time-dependent nature of the metabolic profile has been investigated in rat hepatocytes. Marked differences in the rate of production, extent of accumulation, and distribution between cells and culture medium have been observed for specific metabolites. Species differences in the metabolism of temelastine by rat, dog, cynomolgus monkey, and human hepatocytes have been observed. In particular, SK&F 94224 (a hydroxylated metabolite of temelastine) was not detected in human hepatocyte incubations at appreciable concentrations, but was present in varying amounts in the other species and especially in incubations from dog hepatocytes. Temelastine N-glucuronide was not detected in the rat hepatocyte system but was present to a modest or significant extent in hepatocyte incubations from dog, cynomolgus monkey, and man.

The analysis and characterization of isomeric metabolites of temelastine by the combined use of thermospray liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.

This paper describes the development and application of a combined thermospray liquid chromatographic/mass spectrometric and liquid chromatographic/tandem mass spectrometric method for distinguishing between five isomeric metabolites of Temelastine, comprising four hydroxylated metabolites and one N-oxide. The method allows the unambiguous characterization of all of the isomers either on their own or in the presence of each other. Clear results were obtained for the characterization of these metabolites in biological samples. Temelastine showed extensive phase I and phase II metabolism and the methodology was used to study the aglycone structures of the glucuronide conjugates derived from the hydroxylated metabolites. Photo-diode array ultraviolet spectroscopy was used as a complementary technique to help elucidate the site of glucuronidation in these species.

The structural identification of drug metabolites using thermospray liquid chromatography/mass spectrometry.

The structural identification of drug metabolites has been carried out using thermospray liquid chromatography/mass spectrometry (LC/MS). It has allowed the direct analysis of biological samples, in this case in vitro hepatocyte incubations, with the minimum of sample preparation. The technique also provided molecular weight information on several conjugates including glucuronides, a glutathione conjugate and one unidentified conjugate. A number of minor metabolites were also successfully identified using this method. The examples discussed in this paper illustrate the value of LC/MS in identifying unknown drug metabolites covering a wide polarity range in a complex biological mixture. However, this would not have been possible, if the interface had been unable to handle gradient separations.

Rapid structural analysis of the in vitro and in vivo metabolism of SK & F 95448 by the combined use of thermospray liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.

The thermospray liquid chromatography/mass spectrometry (LC/MS) interface has had a major impact on the direct analysis of the metabolic fate of xenobiotics in complex biological media. This paper outlines the rapidity and power of the LC/MS approach, and shows how detailed structural information can be obtained without recourse to individual compound isolation. This provides a great saving in time and effort. The additional specificity of liquid chromatography/tandem mass spectrometry is highlighted in identifying the sites of metabolic transformation. The ability to handle biological samples with little or no clean-up using wide high-performance liquid chromatographic gradients is a key feature of the success of this methodology.

Application of thermospray liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry for the identification of cynomolgus monkey and human metabolites of SK & F 101468, a dopamine D2 receptor agonist.

A combination of thermospray liquid chromatography-mass spectrometry (LC-MS) and LC MS MS has allowed the structural elucidation of a number of metabolites of 4-[2-(dipropylamino)ethyl]-1,3-dihydro-2H-indol-2-one (SK & F 101468) in monkey urine. By using LC-MS-MS with the third quadrupole (Q3) set up in multiple ion detection (MID) mode, a number of metabolites were subsequently detected in the human urine and plasma samples despite very low dosing regimes. This was achieved with minimal sample preparation, e.g. for the urine sample centrifugation was the only preparative step, in order to remove particulate matter, prior to analysis. The good signal-to-noise ratio obtained for the human samples, using LC MS MS with Q3 set up for MID, raised the possibility of a LC-MS-MS quantitative assay. As a result, the detection limit of this method for SK&F 101468 when dissolved in methanol was determined to be in the region of 20 pg on column.

The disposition of SK&F L-94901, a selective thyromimetic in rat, dog and cynomolgus monkey.

SK&F L-94901 is a novel thyromimetic, structurally related to thyroxine. The absorption, distribution, excretion and metabolism of radiochemically labelled [14C]-SK&F L-94901 has been investigated in the rat, dog and cynomolgus monkey. Oral absorption from solution was low or moderate in all three species. The compound was widely distributed and rapidly excreted, although traces of radioactivity were still evident in some tissues at 7 days post-dose, particularly in the kidney where radioactivity was located in an area approximating to the corticomedullary junction. Elimination of [14C]-SK&F L-94901 was both metabolic, mediated by the liver, and renal. The major metabolic routes of elimination were via oxidative deamination to lactate and acetate derivatives.

Effect of neonatal administration of steroids or gonadectomy upon oestradiol-induced luteinizing hormone release in rats of both sexes.

Implantation of oestradiol into adult rats of both sexes induced different patterns of LH secretion depending on the time at which gonadectomy or testosterone injection were performed. Castration 2 h after birth allowed an LH peak to occur daily at 18.00 h, but its amplitude was lower than that of adult gonadectomized female rats treated with oestradiol. Castration 24 h after birth elicited two kinds of response; a circadian discharge of LH lower than that of male rats gonadectomized 2 h after birth or a steady low level of LH. The LH rhythmicity induced by implantation of oestradiol was not seen after castration at 8 weeks of age. Neonatal administration of testosterone to female rats prevented the LH peak induced by oestradiol that was seen in adult ovariectomized rats. Neonatal or adult ovariectomy did not interfere with the rhythmical response of LH after implantation of oestradiol. Thus, it is concluded that sexual differentiation of the hypothalamus is primarily of masculine origin.

Interaction of the anti-estrogen CI-628 and estradiol on plasma LH and hypothalamic LH-RH in the female rat.

The effects of the anti-estrogen Ci-628 have been tested on both plasma LH and hypothalamic LH-RH content in ovariectomized or ovariectomized, estradiol (E2)-implanted rats, in order to correlate those parameters with the [3H]E2 retention in the hypothalamus and the pituitary. Incresing doses of CI-628 induced a dose-dependent inhibition of [3H]E2 retention in both cytosolic and nuclear fractions of the pituitary. In contrast, hypothalamic retention of [3H]E2 is only inhibited significantly with higher doses of CI-628 (2.4 and 24 mg/kg). In ovariectomized rats, only a high dose of CI-628 (24 mg/kg) is able to decrease elevated LH levels observed following castration. In the presence of E2, CI-628 has both estrogenic and anti-estrogenic properties on LH secretion. CI-628 acts at the pituitary level to decrease the tissue sensitivity to LH-RH, but has no effect on mediobasal hypothalamic (MBH) LH-RH content.