Intravenous administration of L-kynurenine to rhesus monkeys: effect on quinolinate and kynurenate levels in serum and cerebrospinal fluid

The effects of 2-buten-4-olide (2-B40), an endogenous feeding suppressant, on the secretion of luteinizing hormone (LH) were studied in ovariectomized rats. Intraperitoneal (ip) administration of 2-B40: adult female ovariectomized Wistar rats were given daily ip injections of solution containing 2-B40 at 0, 50 or 100 mg/kg body wt for 14 days. This ip treatment with 2-B40 significantly decreased the mean LH concentration and pulse frequency of LH. Intravenous (iv) administration of 2-B40: a solution of 2-B40 (50 or 100 mg/kg body wt) was slowly injected through an intra-atrium catheter and blood samples were taken every 6 min for 2 h. This iv treatment significantly suppressed the LH pulse frequency but had no significant effect on the LH amplitude or mean LH. Injection of 2-B40 into the third cerebroventricle: the injection of 2-B40 into the third cerebroventricle of freely moving rats decreased the mean LH concentration and the frequency and amplitude of LH pulses. Third cerebroventricle injection of a corticotropin-releasing factor (CRF) receptor antagonist before third cerebroventricle injection of 2-B40: the specific CRF receptor antagonist alpha-helical-CRF (9-41) was injected into the third cerebroventricle of ovariectomized rats before injection of 2-B40. Administration of 2-B40 into the third cerebroventricle significantly decreased the mean LH, concentration and pulse frequency. Third cerebroventricle injection of the CRF antagonist at 50 micrograms/rat and then 2-B40 also resulted in significant suppression of the mean LH concentration and pulse frequency.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemostatic profile in nephrotic syndrome

OBJECTIVE: To evaluate the coagulation profile and its relation to steroid therapy, and the frequency of thromboembolic complications and its correlation with coagulation parameters in nephrotic syndrome (NS). SETTING: Hospital based. SUBJECTS AND METHODS: Forty children with NS were subdivided into four groups, namely, fresh cases, steroid dependent, remission after therapy and steroid resistant. An equal number of age and sex matched children served as controls. In all the study and control subjects, detailed clinical examination, liver function tests, renal function tests and detailed coagulation profile were done. Evaluation of renal veins and inferior vena cava for the presence of thrombosis was also done by abdominal ultrasonography. RESULTS: Thrombocytosis was detected in 57.5% and the degree of thrombocytosis was directly related to the amount of proteinuria. The mean prothrombin and thrombin times were within normal range in the study children. The activated partial thromboplastine time (APTT) was prolonged in six cases (15%) and three out of these six children had thromboembolic complications. Antithrombin-III level was significantly lower (p < 0.001) whereas protein C and S were significantly elevated (p < 0.001) as compared to controls. The levels became normal with remission of the disease. Steroid therapy significantly increased the levels of proteins C, protein S. AT-III and fibrinogen as compared to controls. Thromboembolic complications were seen in 3 cases (7.6%) and were associated with very low levels of AT-III and protein C and all three had serum albumin below 2 g/dl. CONCLUSIONS: The importance of coagulation profile in nephrotic syndrome is highlighted and a high index of suspicion for thromboembolic complications is warranted in patients with thrombocytosis, hyper fibrinogenemia, prolonged APTT and in children with low levels of AT-III, protein C and protein S.     

In vitro maintenance of Leishmania amastigotes directly from lesions: advantages and limitations

Leishmania amazonensis (MHOM/BR/77/LTB0016) amastigotes were obtained from mouse cutaneous lesions and maintained in vitro for 48 hr at pH 4.6, 33 C. These organisms were reproducing, capable of transformation to promastigotes, and did not display the promastigote-specific antigen, GP46. In contrast, 97% of the organisms maintained for 24 hr at 31 C, pH 7.3, were positive for GP46. Thus, short-term cultivation of this L. amazonensis strain under appropriate conditions can provide a high yield of amastigotes for various in vivo and in vitro studies. However, the possible interference of host immunoglobin on the surface of these amastigotes needs to be considered because fluorescent-labeled anti-mouse immunoglobulin was detected on 16% of lesion-derived amastigotes even after 114 hr of cultivation.     

Comparison of binding parameters of sigma 1 and sigma 2 binding sites in rat and guinea pig brain membranes: novel subtype-selective trishomocubanes

Comparisons of binding parameters of [3H](+)-pentazocine and [3H]1,3-di-o-tolylguanidine (DTG) at sigma binding sites in guinea pig and rat brain membranes demonstrated that [3H](+)-pentazocine binds to a single high-affinity site, whereas [3H]DTG binds to two high-affinity sites in both species. The Kd values of the radioligands were similar in both types of membranes. However, the density of sigma 1 sites in guinea pig was significantly higher than that of rat. Novel trishomocubanes were tested for their affinities at sigma 1 and sigma 2 binding sites in guinea pig brain membranes using [3H](+)-pentazocine and [3H]DTG as the radioligands. N-(4-Phenylbutyl)-3-hydroxy-4- azahexacyclo[5.4.1.0(2,6).0(3,10).0(5,9).0(8,11)]dodecane (ANSTO-14) showed the highest affinity for the sigma 1 site (Ki = 9.4 nM) and 19-fold sigma 1/sigma 2 selectivity, as a result of increasing the alkyl chain between the cubane moiety and the aromatic ring. N-(3'-Fluorophenyl)methyl- 3-hydroxy-4-azahexacyclo[5.4.1.0(2,6).0(3,10).0(5,9).0(8,11]dodeca ne (ANSTO-19), displayed the highest affinity for sigma 2 sites (Ki = 19.6 nM) and 8-fold sigma 2/sigma 1 selectivity due to a fluoro substitution in the meta position of the aromatic ring. These represent structurally novel lead compounds, especially for the development of selective sigma 2 receptor ligands.     

Physical,optical, and electrical properties of a new conducting polymer

This work studies the electrical and optical properties of the conducting polymer composite films of polypyrrole–chitosan (PPy–CHI). The surface plasmon resonance (SPR) technique was used to study the optical properties of PPy and PPy–CHI composite films. Then, the values of the real and imaginary parts of the refractive indexes of PPy and PPy–CHI films were obtained by nonlinear least square fitting using Fresnel equations for a three-layer system of SPR system. The electrical conductivity measurements showed that the conductivity of the electrochemical prepared films improved in the presence of CHI and can be controlled by varying the CHI amount in the composite. The thermal diffusivity of the PPy–CHI composite films was measured by open photoacoustic spectroscopy and it has been shown that the thermal diffusivity is related to the electron migration in the conjugation chain length. The increase in electromagnetic interference shielding effectiveness (EMI SE) with the increase in electrical conductivity of the films is mostly from shielding by reflection rather than absorption.     

Enzymatic synthesis of N-linked oligosaccharides terminating in multiple sialyl-Lewis(x) and GalNAc-Lewis(x) determinants: clustered glycosides for studying selectin interactions

Galactosyltransferase, sialyltransferase, and fucosyltransferase were used to create a panel of complex oligosaccharides that possess multiple terminal sialyl-Le(x) (NeuAc alpha 2-3Gal[Fuc alpha 1-3] beta 1-4GlcNAc) and GalNAc-Le(x) (GalNAc[Fuc alpha 1-3]beta 1-4GlcNAc). The enzymatic synthesis of tyrosinamide biantennary, triantennary, and tetraantennary N-linked oligosaccharides bearing multiple terminal sialyl-Le(x) was accomplished on the 0.5 mumol scale and the purified products were characterized by electrospray MS and 1H NMR. Likewise, biantennary and triantennary tyrosinamide oligosaccharides bearing multiple terminal GalNAc-Le(x) determinants were synthesized and similarly characterized. The transfer kinetics of human milk alpha 3/4-fucosyltransferase were compared for biantennary oligosaccharide acceptor substrates possessing Gal beta 1-4GlcNAc, GalNAc beta 1-4GlcNAc, and NeuAc alpha 2-3Gal beta 1-4GlcNAc which established NeuAc alpha 2-3Gal beta 1-4GlcNAc as the most efficient acceptor substrate. The resulting complex oligosaccharides were chemically tethered through the tyrosinamide aglycone to the surface of liposomes containing phosphatidylthioethanol, resulting in the generation of glycoliposomes probe which will be useful to study relationships between binding affinity and the micro- and macro-clustering of selectin ligand.     

Voltage- and use-dependent inhibition of Na+ channels in rat sensory neurones by 4030W92, a new antihyperalgesic agent

1. Whole cell patch clamp techniques were used to study the effects of 4030W92 (2,4-diamino-5-(2,3-dichlorophenyl)-6-fluoromethylpyrimidine), a new antihyperalgesic agent, on rat dorsal root ganglion (DRG) neurones. 2. In small diameter, presumably nociceptive DRG neurones under voltage-clamp, 4030W92 (1-100 microM) produced a concentration-related inhibition of slow tetrodotoxin-resistant Na+ currents (TTXR). From a holding potential (Vh) of -90 mV, currents evoked by test pulses to 0 mV were inhibited by 4030W92 with a mean IC50 value of approximately 103 microM. 3. The inhibitory effect of 4030W92 on TTX(R) was both voltage- and use-dependent. Currents evoked from a Vh of -60 mV were inhibited by 4030W92 with a mean IC50 value of 22 microM, which was 5 fold less than the value obtained at -90 mV. Repeated activation of TTX(R) by a train of depolarizing pulses (5 Hz, 20 ms duration) enhanced the inhibitory effects of 4030W92. These data could be explained by a preferential interaction of the drug with inactivation states of the channel. In support of this hypothesis 4030W92 (30 microM) produced a significant hyperpolarizing shift of 10 mV in the slow inactivation curve for TTX(R) and markedly slowed the recovery from channel inactivation. 4. Fast TTX-sensitive Na+ currents (TTXs) were also inhibited by 4030W92 in a voltage-dependent manner. The IC50 values obtained from Vhs of -90 mV and -70 mV were 37 microM and 5 microM, respectively. 4030W92 (30 microM) produced a 13 mV hyperpolarizing shift in the steady-state inactivation curve of TTXs. 5. High threshold voltage-gated Ca2+ currents were only weakly inhibited by 4030W92. The reduction in peak Ca2+ current amplitude produced by 100 microM 4030W92 was 20+/-6% (n=6). Low threshold T-type Ca2+ currents were inhibited by 17+/-8% and 43+/-3% by concentrations of 4030W92 of 30 microM and 100 microM, respectively (n=6). 6. Under current clamp, some cells exhibited broad TTX-resistant action potentials whilst others showed fast TTX-sensitive action potentials in response to a depolarizing current injection. In most cells a long duration (800 ms) supramaximal current injection evoked a train of action potentials. 4030W92 (10-30 microM) had little effect on the first spike in the train but produced a concentration-related inhibition of the later spikes. The number of spikes per train was significantly reduced from 9.7+/-1.5 to 4.2+/-1.0 and 2.6+/-1.1 in the presence of 10 microM and 30 microM 4030W92, respectively (n=5). 7. Thus, 4030W92 is a potent voltage- and use-dependent inhibitor of Na+ channels in sensory neurones. This profile can be explained by a preferential action of the drug on a slow inactivation state of the channel that results in a delayed recovery to the resting state. This state-dependent modulation by 4030W92 of Na+ channels that are important in sensory neurone function may underlie or contribute to the antihyperalgesic profile of this compound observed in vivo.     

Rhesus macaques infected with macrophage-tropic simian immunodeficiency virus (SIVmacR71/17E) exhibit extensive focal segmental and global glomerulosclerosis

We previously showed that inoculation of rhesus macaques with molecularly cloned lymphocytetropic simian immunodeficiency virus (SIVmac239) results in SIV-associated nephropathy (SIVAN) and that the glomerulosclerotic lesions were associated with the selection of macrophagetropic (M-tropic) variants (V. H. Gattone et al., AIDS Res. Hum. Retroviruses 14:1163-1180, 1998). In the present study, seven rhesus macaques were inoculated with M-tropic SIVmacR71/17E, and the renal pathology was examined at necropsy. All SIVmacR71/17E-infected macaques developed AIDS, and most developed other systemic complications, including SIV-induced encephalitis and lentivirus interstitial pneumonia. There was no correlation between the length of infection (42 to 97 days), circulating CD4(+) T-cell counts, and renal disease. Of the seven macaques inoculated with SIVmacR71/17E, five developed significant mesangial hyperplasia and expansion of matrix and four were clearly azotemic (serum urea nitrogen concentration of 40 to 112 mg/dl). These same five macaques developed focal segmental to global glomerulosclerotic lesions. Increased numbers of glomerular CD68(+) cells (monocytes/macrophages) were found in glomeruli but not the tubulointerstitium of the macaques inoculated with SIVmacR71/17E. All macaques had glomerular deposits of immunoglobulin G (IgG), IgM, and tubuloreticular inclusions, and six of seven had IgA deposition. However, there was no correlation between the presence of circulating anti-SIVmac antibodies, immunoglobulin deposition, and glomerular disease. Tubulointerstitial infiltrates were mild, with little or no correlation to azotemia, while microcystic tubules were evident in those with glomerulosclerosis or azotemia. The four most severely affected macaques were positive for diffuse glomerular immunostaining for viral core p27 antigen, and there was intense staining in the glomeruli of the two macaques with the most severe glomerulosclerosis. Viral sequences were isolated from glomerular and tubulointerstitial fractions from macaques with severe glomerulosclerosis but only from the tubulointerstitial compartment of those that did not develop glomerulosclerosis. Interviral recombinant viruses generated with env sequences isolated from glomeruli confirmed the M-tropic nature of the virus found in the glomeruli. The correlation between the increased number of CD68(+) cells (monocytes/macrophages) in the glomeruli, the localization of p27 antigen in the glomeruli, and the glomerular pathology confirms and extends our previous observations of an association between glomerular infection and infiltration by M-tropic virus and SIVAN.