Induction of HLA class II in HTLV-I infected neuronal cell lines

Prenatal methylazoxymethanol acetate (MAMac) injection disrupts cell migration in developing rats. We investigated the electrophysiological characteristics of hippocampal CA1 pyramidal neurons from young MAMac-treated animals (postnatal days 25-35). In vitro intracellular recordings from CA1 cells in MAMac-treated tissue revealed resting membrane potential (mean, -61.5 +/- 1.5 mV), action potential amplitude (mean, 69 +/- 3.1 mV), action potential duration (mean, 2.1 +/- 0.2 ms), input resistance (mean, 51.5 +/- 3.6 M omega) and time constant (mean, 33.2 +/- 1.2 ms) similar to those of CA1 cells from control tissue. However, MAMac-treated tissue could be distinguished as having a higher percentage of cells (62% vs. 10%) which fire a burst of action potentials in response to suprathreshold current injection. The synaptic responses of CA1 cells in MAMac-treated and control tissue were comparable. The CA1 field response to stimulation was also comparable at all stimulus intensities tested (50-1500 microA). Elevation of extracellular potassium concentration ([K+]o) from 3 mM to 6 mM resulted in epileptiform discharge activity in response to stratum radiatum stimulation in all MAMac-treated slices (10/10) but in only one-third of controls (3/9). Spontaneous epileptiform discharges were also observed in the majority (8/13) of MAMac-treated slices bathed in 6 mM KCl but in no controls. These data suggest that MAMac treatment during fetal development not only disrupts normal anatomical organization but also leads to alterations in electrophysiological features of the hippocampal CA1 pyramidal cell region. As such, the MAMac model may provide insights into early onset seizure syndromes associated with developmental abnormalities.     

What are the determinants of children''s exposure to environmental tobacco smoke at home?

Methylazoxymethanol acetate (MAM) is a substance that inhibits migration of neurons in the embryonic brain. After intraperitoneal injection of two different doses of MAM to pregnant rats, microcephaly with or without complete development of the cerebral cortex was observed in every litter. High MAM doses (30 mg/kg) resulted in the lack of superficial layers (II-IV) of the cerebral cortex when the deep layers (V, VI) were seen. The claustrum was present but composed of loosely packed, medium-size, triangular or fusiform neurons with anarchic oriented long axes. After administration of low MAM doses (14 mg/kg) two different parts (medial and lateral) of the insular claustrum were observed. Our results suggest that neurons of the insular claustrum create two different subpopulations of cells, which were similar to that observed in primitive insectivore (e.g., hedgehog), but fuse in development.     

A positive coping strategy. Humour in the oncology setting

We have studied the effects of lead, cadmium and hexavalent chromium in cultured human lymphocytes. Both the proliferative response and the generation of antibodies were evaluated, and the metal accumulation in the cells was measured. Lead added in the range of human exposure caused a significant enhancement in Ig production, which was related to the Pb concentration in the cells. An inhibitory effect on blastogenesis, was detected at Cd doses found in occupationally exposed subjects. Chromium induced reductions in both blastogenesis and Ig production in relation to its capability to enter the cells.     

Soil-Structure Interaction and Pulse Shape Effect on Structural Element Damage to Blast Load

The mode approximation method (MAM) is an effective approach when analyzing dynamic structural responses and damages to blast loading. The pressure-impulse (P-I) diagram generated from the MAM provides an efficient and accurate estimation of structural damage of simple or combined failure modes. In the previous works for damage assessment of underground reinforced concrete structures, the soil-structure interaction (SSI) was simplified as a constant damping or stiffness effect, and the pulse shape effect of the blast load on the P-I diagrams was not discussed. In the present study, a generalized iteration procedure is adopted in derivation of the P-I equations on the basis of the MAM; therefore, the nonconstancy of SSI and the pulse shape effect on underground RC structure damage to blast load can be analyzed. Result of the present study shows that the nonconstancy of SSI and the pulse shape effect has certain effects, and they cannot be simply ignored in damage assessment of buried structures. The generalized iteration procedure is also proved a helpful tool in carrying out such analysis.     

Screening for gestational diabetes mellitus: a critical review

Bovine haptoglobin, which has been recognized as an acute phase protein following tissue injury and inflammation, was detected as a 33 k + 20 k Dalton fraction in the sera from calves transported by road for 2 days. The sera also possessed suppressive activity on lymphocyte proliferative response to concanavalin A. A significant correlation (r = 0.57, P < 0.05) was observed between haptoglobin concentrations and lymphocyte suppression in the sera. Furthermore, the haptoglobin fraction obtained from acute phase sera exerted dose-dependent suppression on lymphocyte blastogenesis. These circumstantial data suggest the possible involvement of bovine haptoglobin, at least in part, as an immunomodulator in serum suppression of lymphocyte blastogenesis in transported calves.     

Expression of the superantigen Mycoplasma arthritidis mitogen in Escherichia coli and characterization of the recombinant protein

Mycoplasma arthritidis mitogen (MAM), is a soluble protein with classical superantigenic properties and is produced by an organism that causes an acute and chronic proliferative arthritis. Unfortunately, the process of obtaining purified MAM from M. arthritidis culture supernatants is extremely time-consuming and costly, and very little material is recovered. Thus, our laboratory has expressed MAM in Escherichia coli by using a protein fusion expression system. The construction and expression of recombinant MAM (rMAM), as well as a comparison of the biological properties of rMAM to those of native MAM, are discussed. Briefly, conversion of the three UGA codons to UGG codons was required to obtain full-length expression and mitogenic activity of rMAM. Antisera to native MAM recognized both rMAM and the fusion protein. The T-cell receptor Vbeta and major histocompatibility complex class II receptor usages by rMAM and the fusion protein were identical to that of native MAM. In addition, the ability to induce suppression and form the superantigen bridge could also be demonstrated with rMAM. Importantly, dose-response experiments indicated that homogeneous native MAM and rMAM were of equal potency. Thus, MAM has been successfully expressed in E. coli, thereby creating a viable alternative to native MAM.     

Heroin antinociception changed from mu to delta receptor in streptozotocin-treated mice

CD-1 mice were treated intravenously with streptozotocin, 200 mg/kg, and tested 2 weeks later or treated with 60 mg/kg and tested 3 days later. Both treatments changed the tail flick response of heroin and 6-monoacetylmorphine (6 MAM) given intracerebroventricularly from a mu- to delta-opioid receptor-mediated action as determined by differential effects of opioid receptor antagonists. The response to morphine remained mu. Heroin and 6 MAM responses involved delta1 (inhibited by 7-benzylidenenaltrexone) and delta2 (inhibited by naltriben) receptors, respectively. These delta-agonist actions did not synergize with the mu-agonist action of morphine in the diabetic mice. The expected synergism between the delta agonist, [D-Pen2-D-Pen5]enkephalin (DPDPE), and morphine was not obtained in diabetic mice. Thus, diabetes disrupted the purported mu/delta-coupled response. In nondiabetic CD-1 mice, heroin and 6 MAM produced a different mu-receptor response (not inhibited by naloxonazine) from that of morphine (inhibited by naloxonazine). Also, these mu actions, unlike that of morphine, did not synergize with DPDPE. The unique receptor actions and changes produced by streptozotocin suggest that extrinsic in addition to genetic factors influence the opioid receptor selectivity of heroin and 6 MAM.     

Patterns of growth deficiency in rats exposed in utero to undernutrition, ethanol, or the neuroteratogen methylazoxymethanol (MAM)

Children and experimental animals exposed to ethanol (EtOH) in utero commonly have low birthweights, and many remain small at maturity. Low body weight or small stature in adulthood may reflect an inability to recover from in utero growth retardation, or it may reflect a separate, postnatal growth deficiency. In this study, daily body weights (postnatal days 1 to 60) were compared among the offspring of the following groups of Long Evans rats: dams fed liquid diet containing 35% EtOH-derived calories; their pair-fed and chow-fed controls; and dams exposed to methylazoxymethanol (MAM) in two previous studies, in which offspring exhibited reduced numbers of growth hormone releasing factor (GRF) neurons. All treatments produced a number of offspring with weight deficits beginning after birth and persisting into maturity. Three distinct patterns of growth deficiency were observed: (1) weight loss relative to controls in the first weeks of life, seen in offspring exposed to EtOH, pair feeding, or MAM on gestation day 13 (G13); (2) a delay in the onset of the prepubertal growth spurt, seen in all EtOH-exposed offspring and in G13 MAM-exposed dwarfs; and (3) failure to sustain the prepubertal growth spurt, seen only after exposure to MAM on G14. The results of this study support the view that prenatal EtOH exposure is capable of affecting postnatal growth specifically; moreover, the pattern of growth deficiency seen in EtOH-exposed offspring was distinct from that of the undernourished offspring of pair-fed dams.     

Effect of pentachlorophenol on immune function

The organochlorine compound, pentachlorophenol, was evaluated for effects on immune system function in male Fisher 344 rats. Pentachlorophenol was prepared in an olive oil vehicle and was administered by oral gavage twice weekly for 28 days at a dose of 2.0 mg/kg per treatment. Exposure to pentachlorophenol increased body weight gains (P=0.024) during the treatment period. Liver (P=0.034) and kidney (P=0.012) body weight ratios were also increased. Pentachlorophenol exposure enhanced T-lymphocyte blastogenesis induced by concanavalin A (Con A)(P=0.0001) and phytohemagglutinin (PHA)(P=0.048) evaluated using stimulation indices. Corresponding B-lymphocyte blastogenesis induced by lipopolysaccharide/dextran (LPS/dex)(P=0.0034) was also enhanced by pentachlorophenol exposure. Pentachlorophenol suppressed the antibody response against sheep red blood cells (SRBCs) by 39% when the response was expressed per viable spleen cell (P=0.006). This suppression was not evident when the response was expressed per spleen (P=0.22), suggesting that a compensatory mechanism or extramedullary splenic hemopoiesis was occurring minimizing the overall impact on humoral immunity. The enhanced B- and T-lymphocyte blastogenesis may also reflect compensatory or hemopoietic activity. Pentachlorophenol exposure had no effect on peritoneal macrophage phagocytosis (P=0.31) or lymphocyte cell surface antigen expression. The observed alterations in lymphocyte blastogenesis and humoral immunity subsequent to pentachlorophenol exposure do not appear to be associated with phagocytosis or lymphocyte cell surface antigen expression.     

Behavioral effects of methylazoxymethanol-induced micrencephaly.

This study was prompted by reports of functionally normal humans with micrencephaly or cortical hypoplasia. Methylazoxymethanol acetate (MAM) treatment, which induces micrencephaly in rats, was administered by injection (20 mg/kg) on Gestational Day 14. Prior to weaning and into adulthood, offspring were assessed on many behavioral tests. There were 3 findings. First, MAM rats (forebrain weight less than two-thirds of controls) were not profoundly hyperactive. Increased activity was seen only on prolonged tests or after amphetamine administration. Second, MAM rats were hypoactive in some conditions. These rats were light shy and less likely to explore lighted areas. MAM rats appeared hyperreactive to environmental stimuli, but not hyperactive. Finally, no MAM effect on behavior was as large as that on brain weight. Thus, as with clinical findings, rat micrencephalics are more remarkable for functional sparing than for behavioral abnormalities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ethanol enhances the mitogen-driven lymphocyte proliferation in patients with psoriasis

Ethanol has been reported to exacerbate psoriasis. Since immunological mechanisms are considered to be important for the pathogenesis of psoriasis, we compared the effects of ethanol on lymphocyte proliferation in 15 healthy control individuals and 15 patients with psoriasis. We employed the spontaneous and phytohemagglutin in (PHA)-induced uptake of 3H-TdR to measure lymphocyte proliferation. Ethanol was added to cultures at concentrations ranging from 0.5 to 0.0005% (vol./vol.). We found that both spontaneous and PHA-driven lymphocyte proliferations were significantly lower in patients with psoriasis (P < 0.002). Spontaneous blastogenesis in both controls and patients remained stable under ethanol. In controls, ethanol suppressed the PHA-driven lymphocyte proliferation in a dose-dependent fashion. By contrast, in patients with psoriasis ethanol significantly increased lymphocyte proliferation by 2-3 times (p < 0.002). Our data indicate that in psoriasis the lower lymphocyte transformation is abnormally enhanced by minimal doses of ethanol.     

Longitudinal studies of immune function in cattle experimentally infected with bovine immunodeficiency-like virus and/or bovine leukemia virus

The effects of single or dual infection with bovine immunodeficiency-like virus (BIV) and/or, bovine leukemia virus (BLV) on bovine immune function were examined over a 4 year period. Holstein calves were infected with BIV (four calves), BLV (five calves), BIV and BLV (five calves), or sham inoculated (three calves). Lymphocyte blastogenesis to mitogens, seven tests of neutrophil function, and mononuclear cell subset analysis by flow cytometry (BoCD4, BoCD8, BoCD2, BoWC1, sIgM+, and monocytes) were performed at regular intervals to 49 months post-infection. These data were analyzed for main effects of each virus and interaction as a 2 x 2 factorial. BIV infected cattle had lower neutrophil antibody-dependent cell-mediated cytotoxicity and iodination responses during 2 of the 4 years post-infection (P < 0.05). BIV infection was not associated with any long-term significant changes in lymphocyte blastogenesis to mitogens or changes in mononuclear cell subset numbers in blood. There was a tendency for animals infected with BIV alone to have decreased lymphocyte blastogenic responses to mitogens, but this was not statistically significant. BLV infection caused an increase in total mononuclear cells with no dramatic shift in the relative proportions of the various subsets. Co-infection with BIV and BLV did not consistently cause a different response than either virus did individually. One BIV infected animal died of non-BLV lymphosarcoma 7 months after infection. All other animals had no unusual clinical signs. In summary, infection with BIV caused a significant, temporary decrease in neutrophil function with no consistent statistically significant alteration in lymphocyte blastogenesis or mononuclear cell numbers during the first 4 years after infection. BLV infection caused an increase in lymphocyte numbers, and there appeared to be no synergism between the viruses.     

Effect of prenatal treatment with methylazoxymethanol on carbachol-, norepinephrine- and glutamate-stimulated phosphoinositide metabolism in the neonatal, young, and adult offspring

Carbachol-, norepinephrine- and glutamate-stimulated phosphoinositide metabolism was investigated in the neonatal, young and adult cerebral cortex slices of rats prenatally treated with methylazoxymethanol (MAM) on gestational day 15 (GD15) or GD19. In rat offspring treated on GD15 there was a significant reduction in the accumulation of [3H]inositol phosphates induced by carbachol and a significant increase in the accumulation of [3H]inositol phosphates induced by norepinephrine on day 7, whereas no changes were observed at the other ages. No significant changes, on the other hand, were observed for glutamate-stimulated phosphoinositide metabolism in GD15 treated rats and for carbachol-, norepinephrine- and glutamate-stimulated phosphoinositide metabolism in animals treated on GD19 at any of the different ages evaluated. These results indicate that treatment with MAM on GD15, which results in a marked microencephaly, causes a marked alteration of muscarinic and alpha 1-adrenergic receptor-stimulated phosphoinositide metabolism during brain development and that these alterations undergo adaptive changes in the adult brain.     

Decreased seizure threshold and more rapid rate of kindling in rats with cortical malformation induced by prenatal treatment with methylazoxymethanol

In humans, cortical malformations are highly epileptogenic. In rats, prenatal treatment with methylazoxymethanol (MAM) cause a diffuse cortical malformation that is yet not associated with seizures. We performed rapid hippocampal kindling in MAM and control rats. We show that MAM rats present (i) a lower initial afterdischarge threshold; (ii) a more rapid progression to generalized seizures. We conclude that MAM rats may serve as models for human epileptogenic cortical malformations.     

Morphological criteria for the therapeutic effectiveness of antirheumatic drugs

Sixteen healthy adults had serial studies of delayed-type skin test reactivity and in vitro lymphocyte blastogenesis to several antigens over a period of 7 months. In many subjects blastogenesis varied broadly from month to month without apparent cause. Responses to all antigens usually increased or decreased together on sequential testing. Blastogenesis to coccidioidin appeared to result largely from cross-reaction with histoplasmin. Humoral factors were not demonstrably responsible for these changes. Blastogenesis rose consistently and non-specifically in subjects following revaccination to vaccinia virus. These studies reflect the lymphocyte blastogenesis reaction as a dynamic equilibrium, subject to spontaneous variation, and responding non-specifically to stimuli such as vaccination. Whatever the causes for these changes, it is clear that serial determinations of blastogenesis response to various antigens do not carry the apparent consistency of the skin test response to that antigen, and single tests must be cautiously interpreted.     

Effects of macrocyclic lactones on ingestion in susceptible and resistant Haemonchus contortus larvae

The effects of ivermectin and ivermectin aglycone on pharyngeal uptake of a carbohydrate substrate (3H-inulin) were measured in larvae of a macrocyclic lactone (ML)-susceptible isolate and 2 ML-resistant isolates of Haemonchus contortus. The resistant isolates showed a tolerance (in terms of the concentration of compound required to reduce feeding to 50%) toward ivermectin of approximately 4.5- and 9-fold and toward ivermectin aglycone of approximately 14-fold, compared to the susceptible isolate. This indicates that susceptible and resistant isolates can be readily distinguished on the basis of the sensitivity of pharyngeal uptake to MLs. The use of various metabolic inhibitors in this assay system did not reveal the nature of the resistance mechanism. Pretreatment of resistant larvae with inhibitors of multidrug resistance mechanisms (P-glycoprotein and multidrug resistance protein) and detoxification enzymes (monooxygenases, esterases, and glutathione transferases) did not reduce their level of tolerance to the ivermectin aglycone.     

Neocortex in the hippocampus: an anatomical and functional study of CA1 heterotopias after prenatal treatment with methylazoxymethanol in rats

Migration disorders cause neurons to differentiate in an abnormal heterotopic position. Although significant insights have been gained into the etiology of these disorders, very little is known about the anatomy of heterotopias. We have studied heterotopic masses arising in the hippocampal CA1 region after prenatal treatment with methylazoxymethanol (MAM) in rats. Heterotopic cells were phenotypically similar to neocortical supragranular neurons and exhibited the same temporal profile of migration and neurogenesis. However, they did not express molecules characteristic of CA1 neurons such as the limbic-associated membrane protein. Horseradish peroxidase injections in heterotopia demonstrated labeled fibers not only in the neocortex and white matter but also in the CA1 stratum radiatum and stratum lacunosum. To study the pathophysiological consequences of this connectivity, we compared the effects of neocortical and limbic seizures on the expression of Fos protein and on cell death in MAM animals. After metrazol-induced seizures, Fos-positive cells were present in CA1 heterotopias, the only hippocampal region to be activated with the neocortex. By contrast, kainic acid-induced seizures caused a prominent delayed cell death in limbic regions and in CA1 heterotopias. Together, these results suggest that neocortical heterotopias in the CA1 region are integrated in both the hippocampal and neocortical circuitry.     

Non-natural aglycones of glycopeptide antibiotics of the vancomycin group. Synthesis and antibacterial activity

A new approach for the modification of the heptapeptide core of glycopeptide antibiotics was proposed based on the replacement of amino acid residues in positions 1 and 3 in teicoplanin aglycone and in position 1 in the eremomycin aglycone. Six novel nonnatural aglycones of the vancomycin type were obtained. Compounds derived from the teicoplanin aglycone exhibited in vitro activity against Gram-positive bacteria, and two of them were also active against the vancomycin-resistant enterococci.