NK-dependent DC maturation is mediated by TNFalpha and IFNgamma released upon engagement of the NKp30 triggering receptor

Natural killer (NK) cells were recently shown to play a relevant role in the process of dendritic cell (DC) maturation. This function is exerted either by direct DC stimulation or through killing those DCs that did not properly acquire a mature phenotype. While killing of immature DCs is dependent on the function of the NKp30 triggering receptor, the mechanism by which NK cells induce DC maturation is still unclear. In this study, we show that also the NK-mediated induction of DC maturation is dependent on NKp30. Upon NK/DC interaction, resulting in NKp30 engagement, NK cells produced tumor necrosis factor alpha (TNFalpha) (and interferon gamma [IFNgamma]) that, in turn, promoted DC maturation. Masking of NKp30 with specific monoclonal antibodies (mAbs) strongly reduced maturation of DCs cocultured with NK cells. In addition, supernatant from NK cells stimulated via NKp30 induced DC maturation, and this effect was neutralized by anti-TNFalpha antibodies (Abs). This NKp30 function is controlled by the HLA-specific inhibitory NK receptors. Accordingly, the ability to promote maturation was essentially confined to NK cells expressing the killer immunoglobulin-like receptor-negative (KIR-) NKG2A(dull) phenotype. Finally, the analysis of perforin-deficient NK cells allowed the dissection of the 2 NKp30-mediated NK-cell functions, since NKp30 could induce cytokine-dependent DC maturation in the absence of NK-mediated DC killing.     

Absence of alpha7-containing neuronal nicotinic acetylcholine receptors does not prevent nicotine-induced seizures

Nicotine is the primary addictive component in tobacco, and at relatively low doses it affects cardiovascular responses, locomotor activity, thermoregulation, learning, memory, and attention. At higher doses nicotine produces seizures. The mechanisms underlying the convulsive effects of nicotine are not known, but studies conducted on a number of inbred strains of mice have indicated a positive correlation between the number of alpha-bungarotoxin (alpha-BTX) binding sites in the hippocampus and the sensitivity to nicotine-induced seizures. Because alpha7-containing neuronal nicotinic acetylcholine receptors (nAChRs) represent the major binding site for alpha-BTX, mice lacking the alpha7 nAChR subunit were predicted to be less sensitive to the convulsive effects of nicotine. To test this hypothesis, we injected nicotine intraperitoneally in alpha7 mutant mice and found that the dose-response curve for nicotine-induced seizures was similar in the alpha7 +/+, alpha7 +/- and alpha7 -/- mice. The retained sensitivity to the convulsant effects of nicotine could not be explained by the presence of cholinergic compensatory mechanisms such as increases in mRNA levels for other nAChR subunits, or changes in binding levels or affinity for nicotinic ligands such as epibatidine and nicotine. These findings indicate that alpha7 may not be necessary for the mechanisms underlying nicotine-induced seizures.     

STUDIES ON THE EFFECT OF DOPAMINE ON THE HUMAN PLATELET RESPONSE

1. The present study investigated the in vitro effect of dopamine on platelet responses in healthy subjects. 2. Dopamine concentrations over 5 mumol/L induced a primary aggregating response and a slight release of alpha-granule proteins, beta-thromboglobulin and platelet factor-4 in all subjects. In 25% of investigated subjects a delayed secondary aggregation was observed with dopamine concentrations over 100 mumol/L. 3. Low dopamine concentrations (5-7.5 nmol/L) increased the platelet sensitivity to other aggregating agents (adenosine diphosphate, collagen and sodium arachidonate). The effect of subaggregating concentrations of serotonin was potentiated by dopamine. 4. The effect of dopamine on platelet responses was prevented by low concentrations of alpha-adrenoceptor antagonists (phentolamine and yohimbine); antagonists of dopamine receptors (haloperidol and domperidone) were able to decrease the extent of the dopamine-induced secondary aggregating wave in the responders, but they failed to prevent the primary aggregation and the effects on platelet response to other aggregating agents. 5. The present data demonstrated that the effects of dopamine on human platelets are mainly mediated by interactions with alpha-adrenoceptors.     

Increased sensitivity to nicotine-induced seizures in mice expressing the L250T alpha 7 nicotinic acetylcholine receptor mutation

High doses of nicotine, the addictive component of tobacco, induce clonic-tonic seizures in animals. Pharmacological and biochemical data have suggested that alpha 7-containing neuronal nicotinic receptors (nAChRs) contribute to these seizures. To study potential alpha 7 contributions, we examined alpha 7 subunits with a Leu250-to-Thr substitution in the channel domain, which creates a gain-of-function mutation. Previous studies have shown that mice homozygous for the alpha 7 L250T mutation (T/T) die shortly after birth, but animals heterozygous for the mutation (+/T) are viable and grow to adulthood. Hippocampal neurons from the +/T mice exhibited altered alpha 7-type currents with increased amplitudes and slower desensitization kinetics, confirming a partial gain of function for the alpha 7 nAChR. We found that +/T mice were more sensitive to the convulsant effects of nicotine compared with their wild-type (+/+) littermates. Furthermore, although their behavior was normal in basal conditions, +/T mice showed a unique nicotine-induced phenotype, consisting of head-bobbing and paw-tapping movements. Increased sensitivity to nicotine-induced seizures occurred despite a 60% decline in brain alpha 7 nAChR protein levels. There were no changes in the levels of alpha 4, alpha 5, alpha 6, alpha 7, beta 2, and beta 4 mRNA, or in [(125)I]epibatidine and [(3)H]nicotine binding between +/T and +/+ mice. Recent data from our laboratory show that alpha 7-null mice maintain normal sensitivity to nicotine-induced seizures. Hence, these present findings suggest that alterations in the properties rather than absence of alpha 7 nAChRs might affect the mechanisms underlying the convulsive properties of nicotine.     

Maternal and neonatal omentin-1 levels in gestational diabetes

Purpose

To evaluate the effect of gestational diabetes on omentin-1 in maternal and cord plasma. As a potent mediator of insulin resistance, Omentin-1, an adipokine derived from human adipose and placental tissue, may be an important player in the pathophysiology of gestational diabetes.

Methods

This was a prospective case–control study. The study included 96 women with gestational diabetes and 96 pregnant women without. Omentin-1 was measured at the time of the oral glucose tolerance test, at 32 weeks in maternal plasma and right after delivery in umbilical cord blood by ELISA assay.

Results

Over a period of 2 years, 200 patients were enrolled. Omentin-1 levels did not significantly differ between both groups throughout the pregnancy: omentin-1 levels were 157 ± 83 ng/ml in women with gestational diabetes and 158 ± 93 ng/ml in women without gestational diabetes (p = 0.94) at time of the oral glucose tolerance test and 118 ± 77 ng/ml in women with diabetes and 150 ± 89 ng/ml in women without (p = 0.12) at 32 weeks, respectively. Both groups showed a decrease in omentin-1 levels throughout pregnancy, with a more pronounced decrease in diabetic women (13 ± 53 versus 4 ± 48 ng/ml; p = 0.5). Neonatal omentin-1 levels were significantly lower in offspring of diabetic mothers: 106 ± 61 versus 134 ± 45 ng/ml (p = 0.03).

Conclusions

There was no significant difference in omentin-1 levels between healthy and diabetic mothers throughout the pregnancy. However, we found significantly lower omentin-1 levels in offspring of diabetic mothers. This may indicate a risk for the development of insulin resistance in later life.

     

Increasing value of autopsies in patients with brain tumors in the molecular era

Journal of Neuro-Oncology - Gliosarcoma is characterized by the World Health Organization as a Grade IV malignant neoplasm and a variant of glioblastoma. The association of race and ethnicity with...     

Supraventricular tachycardia,pregnancy, and water: A new insight in lifesaving treatment of rhythm disorders

Pregnancy may predispose to paroxysmal supraventricular tachycardia (SVT), in subjects with or without identifiable heart disease. Many physiological conditions such as autonomic nervous system changes, altered systemic hemodynamics, etc. can contribute to the onset of arrhythmias during pregnancy. Some cases reported the occurrence of arrhythmias in relation to systemic fluid variations. We report the case of a pregnant woman who experienced SVT due to fluid depletion, detected by bioimpedance vector analysis (BIVA), which was successfully treated by water repletion under tight BIVA monitoring. Emergency physicians can overcome dangerous drug administration by considering historical examination and using fast and reproducible techniques such as BIVA.     

Lactose malabsorption and intolerance: What should be the best clinical management?

Lactose malabsorption (LM) is the incomplete hydrolysis of lactose due to lactase deficiency, which may occur as a primary disorder or secondary to other intestinal diseases. Primary adult-type hypolactasia is an autosomal recessive condition resulting from the physiological decline of lactase activity. Different methods have been used to diagnose LM. Lactose breath test represents the most reliable technique. A recent consensus conference has proposed the more physiological dosage of 25 g of lactose and a standardized procedure for breath testing. Recently a new genetic test, based on C/T13910 polymorphism, has been proposed for the diagnosis of adult-type hypolactasia, complementing the role of breath testing. LM represents a wellknown cause of abdominal symptoms although only some lactose malabsorbers are also intolerants. Diagnosing lactose intolerance is not straightforward. Many non-malabsorber subjects diagnose themselves as being lactose intolerant. Blind lactose challenge studies should be recommended to obtain objective results. Besides several studies indicate that subjects with lactose intolerance can ingest up to 15 g of lactose with no or minor symptoms. Therefore a therapeutic strategy consists of a lactose restricted diet avoiding the nutritional disadvantages of reduced calcium and vitamin intake. Various pharmacological options are also available. Unfortunately there is insufficient evidence that these therapies are effective. Further double-blind studies are needed to demonstrate treatment effectiveness in lactose intolerance.     

Lack of association between IDE genetic variability and Down's syndrome

Virtually all patients with Down's syndrome develop Alzheimer disease (AD) during their life; thus, it is extremely important to investigate potential determinants of AD in this population. Previous studies found an association of DS with -48C/T presenilin-1 and with the -850 tumor necrosis factor-alpha, two polymorphisms of genes involved in amyloid beta modulation In this study, we evaluated whether the insulin-degrading enzyme (IDE), a protease involved in the degradation of endogenous brain-derived Abeta peptides, is involved in DS-related AD. To this end, 287 DS patients were compared with 251 apparently healthy controls, in order to assess the association between DS and two single nucleotide polymorphisms located on the introns 14 and 24 of the IDE gene. The comparison of allele and genotype distribution between cases and controls showed no evidence for an association with regard to IDE polymorphism, for both the SNPs (i.e., IDE 185 and IDE 199). In conclusion, the findings of our study suggest that the two IDE polymorphisms considered in the analysis do not appear to play a major role in DS-related AD.