Benzodiazepine modulation of recombinant alpha1beta3gamma2 GABA(A) receptor function efficacy determination using the Cytosensor microphysiometer

The nonsteroidal antioestrogen tamoxifen has been shown to block a number of voltage-gated cation-selective channels but its effect on ligand-gated cation-selective channels has not been studied. We have investigated the action of tamoxifen and the related derivative toremifene on ligand-gated cationic nicotinic acetylcholine and 5-HT3 receptor channels. Tamoxifen and toremifene both inhibited cationic currents of adult-type human muscle nicotinic acetylcholine receptors expressed in Xenopus oocytes with similar IC50 values of 1.2 +/- 0.03 microM (nH = 0.84 +/- 0.02) and 1.2 +/- 0.1 microM (nH = 1.1 +/- 0.1), respectively. Tamoxifen could also block native 5-HT3 receptors in NG108-15 neuroblastoma/glioma hybrid cells with IC50 = 0.81 +/- 0.15 microM and nH of 1.3 +/- 0.3. The characteristics of block by tamoxifen at the 5-HT3 receptor were voltage- and use-independent. The inhibition of the 5-HT-evoked currents were not overcome by increasing concentrations of 5-HT consistent with a noncompetitive mechanism of block.     

A fetal sheep liver extract reverses age-related increments in spontaneous and induced cytokine production by indirect environmental effects

BALB/c, DBA/2 and C57BL/6 mice of different ages (ranging from 8 to 110 weeks of age) were used as spleen cell donors to assay cytokine production from ConA activated spleen and Peyer's Patch (PP) lymphocytes. As reported in an earlier publication, there was an age-related decline in IL-2 production in all strains, with a general increase in IL-4 and IL-10 production with age, this being particularly marked for PP cell preparations. Similar conclusions were reached from independent analysis of CD44hi and CD44lo cell populations in these groups (memory vs. naive cells, respectively). Interestingly, IL-6 production was dramatically increased (some 4-5-fold in the different strains) and significantly increased levels of IL-6 were detected in the serum of aged mice. A previously described sheep fetal liver extract was able to reverse, to varying degrees, these cytokine changes associated with aging. Interestingly, when cells from aged mice were adoptively transferred to lethally irradiated young (8 week) recipients, the cytokine production phenotype of cells harvested from recipient mice 3 weeks later was that of the aged donor, unless recipients were treated continually with extract. Treatment of the donor alone produced minimal changes in cytokine production 3 weeks following adoptive transfer. The effect of extract was reversed in treated aged mice by concomitant daily intravenous infusion of the competitive inhibitor of nitric oxide synthesis (NG-monomethyl-L-arginine (NMMA)), which also decreased the increased serum nitrate levels in mice treated with extract. Our data suggest an important role for reactive nitrogen products, themselves induced by fetal liver extract, in age-associated changes in cytokine production.     

Parameter estimates for direct, maternal, and grandmaternal genetic effects for birth weight and weaning weight in Hereford cattle

Birth and weaning weights adjusted for age of dam from four lines of Hereford cattle were analyzed to determine the relationships among grandmaternal, maternal, and direct genetic effects. Three lines were selected for 1) weaning weight (WWL), 2) yearling weight (YWL), and 3) an index of yearling weight and muscle score (IXL). The fourth line was an unselected control line (CTL). Numbers of observations ranged from 1,699 (CTL) to 2,811 (WWL), and number of animals in the pedigree file ranged from 2,266 to 3,192. Two animal models were used to obtain estimates by REML using an average information method. Model 1 included random direct and maternal genetic, permanent maternal environmental, and residual environmental effects, and fixed sex x year effects. Model 2 additionally included random grandmaternal genetic and permanent grandmaternal environmental effects. For birth weight, Models 1 and 2 gave almost identical estimates for direct and maternal heritability, and for the fraction of variance that was due to maternal permanent environmental effects. Estimates for grandmaternal heritability could be obtained only for IXL (.03) and CTL (.01). For weaning weight, estimates for direct heritability were similar from both models. Estimates for maternal heritability from Model 1 were .18, .20, .13, and .20, and corresponding estimates from Model 2 were .34, .31, .13, and .34 for WWL, YWL, IXL, and CTL, respectively. For IXL, estimates for variances that were due to grandmaternal genetic and grandmaternal permanent environmental variances could not be obtained and were set to zero. Grandmaternal heritability estimates for WWL, YWL, and CTL were .05, .09, and .12. Estimates of correlations between direct and maternal genetic effects were -.13, -.44, -.11, and -.26 for WWL, YWL, IXL, and CTL. Estimates of correlations between direct and grandmaternal genetic effects were .21, .83, and .55, and those between maternal and grandmaternal genetic effects were -.99, -.84, and -.76 for WWL, YWL, and CTL, respectively. These results indicate that grandmaternal effects may be important for weaning weight and that maternal heritability may be underestimated if grandmaternal effects are not included in the model.     

Loss of glucose transport in developing avian red cells

OBJECTIVE: This study aimed to examine the characteristics of intraretinal changes associated with macular holes and epiretinal membranes by scanning retinal thickness analysis. STUDY DESIGN: The study design was a nonconsecutive case series. PATIENTS: Fifty-six eyes of patients who had either a suspected or clinically diagnosed macular hole or epiretinal membrane were recruited. INTERVENTIONS: A commercial prototype of the scanning retinal thickness analyzer (RTA) was used. It projected a laser slit beam onto the retina and scanned it, in 200 or 400 msec, across a 2- x 2-mm area, yielding multiple optical cross sections that were recorded digitally. RESULTS: Epiretinal membranes were detected, and sites of attachment could be identified. Full-thickness holes corresponded to intraretinal cavities in which the inner retinal surface was broken, usually at the center. The majority of eyes with full-thickness macular holes showed increased retinal thickness surrounding the hole. The so-called "cuff of subretinal fluid," however, often was not present by retinal thickness analysis, despite clinical diagnosis to the contrary, even though retinal thickness analysis is capable of detecting such fluid. In 20 (42%) of 47 eyes diagnosed or suspected of having macular holes, scanning retinal thickness analysis showed findings different from those reported by retinal specialists. CONCLUSIONS: Examination of macular holes with the scanning RTA provides useful information in the diagnosis of macular holes in addition to that obtained through conventional techniques. The findings support the idea that many macular holes develop in association with intraretinal cystic changes. The precise chronology of the events remains to be determined.     

Memorizing and recalling spatial-temporal patterns in an oscillator model of the hippocampus

We describe the model of the hippocampus consisting of interactive oscillators with input from the entorhinal cortex (modulating the main information flow by a theta rhythm) and the septum (a theta rhythm generator). When interconnections between oscillators are allowed to strengthen in an adaptive way, the network can be trained using a series of lessons. This results in a connection matrix that memorizes the temporal sequence of inputs. Presenting one of the lessons to the trained network results in reproduction of the remainder of the sequence. In this paper, we create such a connection matrix, derive from it an appropriate Markov chain and simulate the chain to illustrate its dynamics.     

The risk of non-Hodgkin's lymphoma after Hodgkin's disease, with special reference to splenic treatment

BACKGROUND AND OBJECTIVE: One of the consequences of the enormous improvement in survival rates of patients treated for Hodgkin's disease (HD) is the emergence in the long term of treatment-related complications, particularly secondary cancers. This study was undertaken to observe the occurrence of non-Hodgkin's lymphoma (NHL) in patients treated for HD and to identify the etiological role of various risk factors, especially spleen irradiation, in the pathogenesis of this illness. DESIGN AND METHODS: From 1972 to 1996, the Department of Radiation Oncology and the Hematology Section of "La Sapienza" University of Rome observed and analyzed the occurrence of NHL in 1,391 patients treated for HD. The average follow-up period was 84 months. For a more accurate calculation of the risk of the occurrence of NHL, the patients were first divided into 3 groups according to their initial treatment and also according to the total treatment they had received. Then, in order to establish the possible connection between NHL and splenic treatment the patients were also divided into 3 subgroups according to whether they had undergone splenectomy, splenic irradiation or neither of these. Two different methods of statistical analysis were used: (a) the cumulative risk (confidence interval) was evaluated in relation to treatment (initial and at the time of salvage) and (b) the Cox model was applied to identify the variables which play a role in the appearance of NHL. The cumulative risk of developing NHL was assessed using the Kaplan and Meier method. A multivariate analysis was performed using the Cox Proportional Hazard Model. RESULTS: A total of 20 cases of NHL were observed, appearing between 17 and 206 months after initial treatment. The cumulative risk was 0.8%, 1.8%, 2.6% and 3.5% at 5, 10, 15 and 20 years respectively. According to the multivariate analysis, significant risk factors were splenic irradiation and age (> 40 years). Splenic irradiation (vs no splenectomy/no splenic irradiation) showed a relative risk of 5.69, p = 0.0280, while age over 40 showed a relative risk of 3.05, p = 0.0152. INTERPRETATION AND CONCLUSIONS: From the results of this study, if appears that there is a possibility that splenic irradiation and age over 40 increase the risk of NHL in HD patients. Further studies are needed to investigate in greater depth the role of spleen irradiation in the occurrence of this illness.     

Compartmentation of [14C]glutamate and [14C]glutamine oxidative metabolism in the rat hippocampus as determined by microdialysis

Metabolic compartmentation of amino acid metabolism in brain is exemplified by the differential synthesis of glutamate and glutamine from the identical precursor and by the localization of the enzyme glutamine synthetase in glial cells. In the current study, we determined if the oxidative metabolism of glutamate and glutamine was also compartmentalized. The relative oxidation rates of glutamate and glutamine in the hippocampus of free-moving rats was determined by using microdialysis both to infuse the radioactive substrate and to collect 14CO2 generated during their oxidation. At the end of the oxidation experiment, the radioactive substrate was replaced by artificial CSF, 2 min-fractions were collected, and the specific activities of glutamate and glutamine were determined. Extrapolation of the specific activity back to the time that artificial CSF replaced 14C-amino acids in the microdialysis probe yielded an approximation of the interstitial specific activity during the oxidation. The extrapolated interstitial specific activities for [14C]glutamate and [14C]glutamine were 59 +/- 18 and 2.1 +/- 0.5 dpm/pmol, respectively. The initial infused specific activities for [U-14C]glutamate and [U-14C]glutamine were 408 +/- 8 and 387 +/- 1 dpm/pmol, respectively. The dilution of glutamine was greater than that of glutamate, consistent with the difference in concentrations of these amino acids in the interstitial space. Based on the extrapolated interstitial specific activities, the rate of glutamine oxidation exceeds that of glutamate oxidation by a factor of 5.3. These data indicate compartmentation of either uptake and/or oxidative metabolism of these two amino acids. The presence of [14C]glutamine in the interstitial space when [14C]glutamate was perfused into the brain provided further evidence for the glutamate/glutamine cycle in brain.