Sugarcane growth promotion by the endophytic bacterium Pantoea agglomerans 33.1

The promotion of sugarcane growth by the endophytic Pantoea agglomerans strain 33.1 was studied under gnotobiotic and greenhouse conditions. The green fluorescent protein (GFP)-tagged strain P. agglomerans 33.1::pNKGFP was monitored in vitro in sugarcane plants by microscopy, reisolation, and quantitative PCR (qPCR). Using qPCR and reisolation 4 and 15 days after inoculation, we observed that GFP-tagged strains reached similar density levels both in the rhizosphere and inside the roots and aerial plant tissues. Microscopic analysis was performed at 5, 10, and 18 days after inoculation. Under greenhouse conditions, P. agglomerans 33.1-inoculated sugarcane plants presented more dry mass 30 days after inoculation. Cross-colonization was confirmed by reisolation of the GFP-tagged strain. These data demonstrate that 33.1::pNKGFP is a superior colonizer of sugarcane due to its ability to colonize a number of different plant parts. The growth promotion observed in colonized plants may be related to the ability of P. agglomerans 33.1 to synthesize indoleacetic acid and solubilize phosphate. Additionally, this strain may trigger chitinase and cellulase production by plant roots, suggesting the induction of a plant defense system. However, levels of indigenous bacterial colonization did not vary between inoculated and noninoculated sugarcane plants under greenhouse conditions, suggesting that the presence of P. agglomerans 33.1 has no effect on these communities. In this study, different techniques were used to monitor 33.1::pNKGFP during sugarcane cross-colonization, and our results suggested that this plant growth promoter could be used with other crops. The interaction between sugarcane and P. agglomerans 33.1 has important benefits that promote the plant's growth and fitness.

Cardiac myocytes and dendritic cells harbor human immunodeficiency virus in infected patients with and without cardiac dysfunction: detection by multiplex, nested, polymerase chain reaction in individually microdissected cells from right ventricular endomyocardial biopsy tissue

Two hundred fifteen patients infected with human immunodeficiency virus (HIV) participated in a prospective longitudinal study of HIV-related heart disease. Evaluation included signal-averaged electrocardiography and echocardiography. Fifteen patients underwent endomyocardial biopsy, 5 had cardiovascular symptoms and 10 did not. Cardiac myocytes or dendritic cells were prepared by individual cell microdissection to sort them from other cell types such as interstitial cells or circulating blood elements. HIV proviral sequences were amplified in samples of 15 to 20 cells of each type by multiplex, nested, polymerase chain reaction and hybridized to 32P-labeled probes specific for regions within the gag and pol genes of HIV-1. The results showed the presence of HIV sequences in myocytes of 2 of 5 patients with cardiac symptoms and in 6 of 10 without. Thus, symptomatic HIV cardiomyopathy did not appear to be a direct consequence of the virus on myocardial cells. In dendritic cells, HIV sequences were detected in 5 of 5 patients with cardiac symptoms and in 8 of 10 with apparently normal ventricular function. Furthermore, dendritic cells were somewhat more numerous in the myocardium of symptomatic than asymptomatic patients. Our studies are the first to directly detect the HIV genome in purified cardiac myocytes from patients with and without cardiac dysfunction. Our findings do not support a direct role of the virus in myocardial dysfunction. However, the results do suggest that the interstitial dendritic cells may be involved in some manner in the development of cardiac dysfunction observed in HIV-infected patients.

Serum pyridinoline as a specific marker of collagen breakdown and bone metabolism in hemodialysis patients

Type I collagen represents more than 90% of bone matrix. Quantitative analysis of collagen cross-link molecules such as pyridinoline (PYD) provides valuable information on bone resorption rate. We have studied 37 hemodialysis patients who underwent a systematic transiliac bone biopsy for histomorphometry study. Eighteen of them had tetracycline double labeling, allowing to determine dynamic, in addition to static bone parameters. Measurement of serum-free PYD was performed using a new competitive enzyme immunoassay. Serum PYD values were compared with those of three other serum markers of bone metabolism, namely intact PTH (iPTH), bone-specific alkaline phosphatase (bAP), and osteocalcin, for the correlations with bone histomorphometric parameters. Serum PYD levels (mean +/- SD) were significantly higher in dialysis patients than in normal individuals, 90.6 +/- 99.6 nM versus 1.9 +/- 0.4 nM, respectively. Patients with high turnover bone disease had significantly higher serum PYD levels than patients with normal or low bone turnover, 108.8 +/- 108.0 nM versus 34.1 +/- 12.8 nM, respectively. Serum PYD levels were positively correlated with bone resorption parameters including osteoclast surface (r = 0.59, p < 0.0001) and osteoclast number/mm2 (r = 0.61, p < 0.0001), and also with bone formation parameters, osteoblast surface (r = 0.43, p < 0.008), double-labeled surface (r = 0.81, p < 0.001), and BFR (r = 0.91, p < 0.0001). The BFR was better correlated with serum PYD levels than with either serum iPTH or osteocalcin concentrations. However, correlation with serum bAP was comparable.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of two community-wide smoking cessation contests

The Pawtucket (Rhode Island) Heart Health Program is designed to effect a community-wide change in heart disease morbidity and mortality by reducing smoking prevalence and other behavioral risks for this disease. The initial emphasis of the Pawtucket Heart Health Program was on the development of risk factor programs within specific churches, work sites, and other organizations in the community. At the end of 9 months of programming, however, only one organization had elected to begin a stop-smoking program. Given the community smoking prevalence of 43.4%, it was decided that larger-scale interventions would be required if a significant public health impact was to be realized. Therefore, a community-wide campaign was mounted to recruit as many participants as possible into the "Up in Smoke" cessation program. A lottery was attached to this program, with the contingency based on program attendance rather than cessation per se. One hundred three participants, including residents of neighboring communities, enrolled in three Up in Smoke lottery groups. At a 3-month follow-up, only 11 (7%) of smokers from the Up in Smoke lottery reported that they were not smoking (10% of those actually contacted). For a variety of reasons, the "Quit and Win" approach was later adopted by the Pawtucket Heart Health Program as the primary smoking intervention. One month after the end of the contest, 20% of those contacted reported not smoking. The percentage of quitters for the Up in Smoke program increased while the Quit and Win rate decreased over longer periods of follow-up. These and other data were compared with those of participants of a screening program conducted concurrently. Lotteries in general and face-to-face recruitment in large crowds were shown to be effective recruiting methods for large-scale smoking cessation programs.

Genetic linkage between serum levels of the third component of complement and the H-2 complex

AKR/J (H-2kk) mice have higher serum C3 levels than DBA/2J (H-2dd). The F1 hybrids have intermediate levels. Analysis of the progeny of backcrosses at 21 days of age shows that C3 levels in mice of H-2dk type are significantly higher than those with H-2dd type and lower than those with H-2kk type. In addition, mice of H-2kk, H-2dk, and H-2dd types have C3 levels not significantly different from those of AKR/J, AKD2F1, and DBA/2J respectively. These findings demonstrate linkage between a gene controlling C3 levels and the H-2 complex.

Interactions between calcium, phosphate, and albumin on the surface of titanium

The deposition of calcium phosphate on chemically polished commercially pure titanium immersed in Hank's balanced salt solution (HBSS) with bovine serum albumin (BSA) (concentrations 0 and 4 mg/mL) has been investigated. Electrochemical techniques, 125I labeling of albumin, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used. A tricalcium phosphate layer with a thickness of ca. 1 microm was formed for periods of immersion in HBSS ranging between 1 and 2 weeks. A concentration of 4 mg/mL of BSA prevented its formation, even for periods as long as 1 month. In the absence of BSA, the electrochemical behavior of titanium specimens was significantly affected by the length of immersion time, reflecting the changes that slowly occur on their surface. In the presence of BSA, the surfaces maintained most of their original electrochemical activity. Surface studies have shown that calcium and phosphate become incorporated in the surface at very early stages of immersion. Albumin, which was rapidly adsorbed on titanium, was slowly desorbed when titanium was placed in HBSS. Protein and phosphate may coexist on the same surface, but initially adsorbed albumin molecules prevent the precipitation of a thick layer of tricalcium phosphate.

Experimental anxiety in the black and white model in cycling, pregnant and lactating rats

This study demonstrates changes in experimental anxiety assessed in the black and white paradigm during various reproductive states of female rats. Low levels of experimental anxiety were observed during late proestrus and on day 17 of gestation, stages related to high progesterone (P) levels. In estrus, metestrus, diestrus and on day 21 of gestation, stages characterized by low P concentrations, high levels of experimental anxiety, similar to those exhibited by ovariectomized females, were found. No changes in experimental anxiety were observed on day 8 of lactation compared to ovariectomized females. These data are discussed from the standpoint of the putative anxiolytic-like effect of progestins.

Novel cosmetic formulations containing a biosurfactant from Lactobacillus paracasei

Cosmetic and personal care products including toothpaste, shampoo, creams, makeup, among others, are usually formulated with petroleum-based surfactants, although in the last years the consume trend for "green" products is inducing the replacement of surface-active agents in these formulations by natural surfactants, so-called biosurfactants. In addition to their surfactant capacity, many biosurfactants can act as good emulsifiers, which is an extra advantage in the preparation of green cosmetic products. In this work, a biosurfactant obtained from Lactobacillus paracasei was used as a stabilizing agent in oil-in-water emulsions containing essential oils and natural antioxidant extract. In the presence of biosurfactant, maximum percentages of emulsion volumes (EV=100%) were observed, with droplets sizes about 199nm. These results were comparable with the ones obtained using sodium dodecyl sulfate (SDS), a synthetic well known surfactant with high emulsify capacity. Moreover, the biosurfactant and emulsions cytotoxicity was evaluated using a mouse fibroblast cell line. Solutions containing 5g/L of biosurfactant presented cell proliferation values of 97%, whereas 0.5g/L of SDS showed a strong inhibitory effect. Overall, the results herein gathered are very promising towards the development of new green cosmetic formulations.

Behavioural similarities between mother rats and benzodiazepine-treated non-maternal animals

Mother rats nursing large litters are hyperphagic, aggressive towards conspecifics, and show less freezing behaviour than non-maternal animals. These naturally occurring adaptations resemble those elicited by benzodiazepine treatment in virgin rats, indicating a common neurochemical change in the brains of mother rats and benzodiazepine-treated virgins. In line with this hypothesis, it was found that three functional benzodiazepine antagonists (FG 7142, pentylenetetrazol, caffeine) decreased food intake, lowered aggression and strengthened freezing in lactating mother rats. These psychopharmacological observations support the idea that GABA neurotransmission is enhanced during motherhood in the rat.

Behavior of mother rats in conflict tests sensitive to antianxiety agents

Previous studies of freezing and open-field activity have demonstrated that lactating rats are less fearful or less anxious than nonpregnant ones. The purpose of this investigation was to observe the behavior of mother rats in conflict tests, which are frequently used in studies on the neurobiology of anxiety. In the punished drinking test, in which licking from a water spout is punished by electric shocks, mothers (observed on Day 1 postpartum following 24 hr of water deprivation) were found to drink more than virgins. Mothers (Day 1 postpartum) also consumed more food than controls in an unfamiliar open field. In contrast, no difference between mothers (Day 5 postpartum) and virgins was present in the exploration of an electrified shock probe. The largest maternal anticonflict effects in the drinking and feeding tests were recorded when the females were tested with their pups. Increased punished drinking was also observed in virgin rats treated with the anxiolytic benzodiazepine midazolam. Water-deprived virgins and mothers did not differ in the shock titration test, a result suggesting that diminished pain reactivity was unlikely to account for the increased punished drinking in mothers. Moreover, females in late pregnancy, which are hypoalgesic (Gintzler, 1980), did not lick more than virgins in the punished drinking test. Following 24 hr of water deprivation, unpunished drinking was higher in lactating females than in virgins, so the increased acceptance of punishment by mothers might have been due to their being more thirsty than virgins.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of brain natriuretic peptide in the diagnosis of heart failure

A diagnosis of heart failure (HF) can be difficult, especially in patients with mild symptomatology. The purpose of this study was to evaluate the significance of brain natriuretic peptide (BNP) in the diagnosis of HF with systolic or isolated diastolic ventricular dysfunction. One hundred patients and 9 controls were included in the study. Eighty-five patients were diagnosed with HF, based on clinical and echocardiographic findings. BNP levels were accurate for the diagnosis of HF, with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.92. In addition, BNP levels showed an excellent accuracy for the diagnosis of isolated diastolic HF (AUC = 0.89). These data suggest that the measurement of BNP levels may be helpful in the diagnosis of HF and in selecting patients for further evaluation. Furthermore, BNP measurement can play an important role in the diagnosis of isolated diastolic HF.

An immunocytochemical and biochemical study of the microtubule-associated protein MAP-2 during post-lesion dendritic remodeling in the central nervous system of adult rats

A monoclonal antibody against the microtubule-associated protein MAP-2 was used to examine the fate of this molecule during post-lesion dendritic remodeling in the hippocampus and septum of adult rats. Qualitative and quantitative immunocytochemical analyses were carried out in the dentate gyrus after unilateral destruction of the entorhinal cortex (EC). An increase in MAP-2 immunoreactivity was detected in dendritic processes located in the outer 2/3 of the ipsilateral molecular layer (ML) 2 days after the lesion. whereas dendritic staining decreased considerably in the inner 1/3 of the same ML. The increase of staining was also detected 4, 6 and 8 days after the lesion; it was accompanied by an increase in the immunoreactivity in the inner 1/3 of the ML. After that period, a progressive decrease in anti-MAP-2 staining toward control levels was detected along the whole extent of the ipsilateral ML. This was concurrent with alterations in dendritic orientation, and a decrease in stained dendrites in the inner 1/3 of the ML. By 30 days post-lesion anti-MAP-2 staining was almost identical to that of the contralateral ML, although the alterations in dendritic morphology were still present in the ipsilateral ML. Changes in MAP-2 levels were also evaluated by densitometry of Western blots or dot immunobinding of hippocampal extracts obtained at different post-lesion intervals. The results obtained revealed a pattern of change in MAP-2 levels identical to that observed with the immunohistochemical stain. A similar, immunocytochemical and biochemical, analysis conducted in the lateral septal nucleus after unilateral transection of the fimbria showed no changes in the distribution and/or content of MAP-2 at any post-lesion interval analyzed (2, 10 and 20 days post-lesion). The present observations show that post-lesion dendritic remodeling is concurrent with modifications in the levels and distribution of MAP-2. These modifications suggest that the dendritic cytoskeleton is dynamically changing in response to perturbation of the synaptic environment. In addition, our results indicate that these changes may only occur in those neurons which have the capability to remodel their post-synaptic surface in response to deafferentation.

Motivational aspects of maternal anxiolysis in lactating rats

RATIONALE AND OBJECTIVE

This study examines the role of maternal motivation on the reduced anxiety-like responses displayed by lactating rats in the plus maze test.

RESULTS

Maternal animals, both lactating and sensitized (ovariectomized females behaving maternal after a continuous exposure to pups), displayed anxiolytic-like responses in the plus maze test in contrast to ovariectomized non-maternal rats. However, the levels of experimental anxiety were lower in lactating than in sensitized females. Pups placed in the open arms of the maze further reduced the low levels of anxiety-like behavior of both sensitized and lactating rats. Low doses of haloperidol (0.05 and 0.1 mg/kg), a dopamine antagonist, which interfere with maternal motivation but has neither anxiolytic nor anxiogenic effect in the plus maze test, significantly increased the anxiety-like responses of lactating rats. The presence of the pups in the open arms of the maze overrode the behavioral effect of haloperidol on lactating dams' anxiety-related behavior.

CONCLUSIONS

These experiments show that maternity induces changes in the way the animals react to the environment, rendering them less anxious to aversive stimuli. The degree of experimental anxiolysis displayed by maternal animals varies according to their maternal motivation, which is modulated by the female's endocrine state, the pups and/or the dopaminergic system.

Purificaiton and characterization of mouse serum protein with specific binding affinity for C4 (Ss protein)

A new component of the complement (C).system, with a specific binding affinity for the activated Ss-protein (C4) has been identified in mouse serum. This protein, named Ss- (or C4)-binding protein (Ss-bp), was purified about 200 times from mouse plasma. Ss-bp is a heat stable (56 degrees C, 60 rain) beta-globulin with a sedimentation coefficient in sucrose density ultracentrifugation of 10s. Its concentration in serum of adult male and female mice is 160 and 60 mug/ml, respectively. In EDTA-plasma, Ss and Ss-bp are not associated and can be separated by chromatography in Sephadex G-200. However, in serum Ss-bp binds tightly to Ss. The bonds between these proteins cannot be reversed by chelation of divalent cations. As a consequence of the formation of Ss/Ss-bp complexes, the properties of Ss-bp appear to be quite different in serum of mice with high (Ss-H) or low (Ss-L) levels of Ss-protein. In Ss-H serum, all of Ss- bp is bound to Ss. In Ss-L serum, Ss-bp is mostly free. Because the electrophoretic mobilities of free and complexed Ss-bp are quite different, Ss-bp appears to be polymorphic in serum (but not in EDTA- plasma). The strict dependency of the apparent electrophoretic mobility of Ss-bp on the levels of Ss in serum was demonstrated in a series of congenic mice and among the progeny of a cross between Ss-H and Ss-L strains of mice. Without exception, the slow and fast varieties of Ss-bp were associated with the Ss-L and Ss-H traits. Ss-bp of the slow variety can be transformed into the fast variety by addition of pure human C4, or C4-sufficient guinea pig serum, to Ss-L serum. In both instances Ss-bp formed stable complexes with C4 or a C4- derived peptide. These findings highlight the binding specificity of Ss- bp for the fourth component of the complement system, and in addition they demonstrate a functional homology between the Ss-protein and C4 from two different species.

Sequential analysis of K-ras mutations in aberrant crypt foci and colonic tumors induced by azoxymethane in Fischer-344 rats on high-risk diet

Forty Fischer-344 male rats were given a high-risk diet (HRD) that was high in fat, low in fiber and low in calcium. After 4 weeks, the rats were given two weekly s.c. injections of azoxymethane (AOM, 15 mg/kg body wt), and remained on the same diet till death. Eight rats were killed at 12 weeks and again at 20 weeks in order to microdissect aberrant crypt foci (ACF) containing four or more crypts/focus from their colons. The remaining 24 rats were killed at 30 weeks to harvest colonic tumors. The polymerase chain reaction (PCR) was used to amplify specific DNA segments in the K-ras gene from ACF and colonic tumors. The PCR-amplified DNAs were sequenced to identify the point mutations in codons 12 and 13. All the mutations detected in the ACF and colonic tumors were G to A transitions in the second position of codon 12. These mutations were present in the ACF of 2/8 (25%) and 3/8 (37%) rats at 12 and 20 weeks respectively. The mutations were present in colonic tumors of 7/24 (29%) rats. These results provide important evidence for the significance of K-ras mutations in ACF (> 4 crypts/focus) as early markers of malignant potential in the colons of F344 rats exposed to AOM while receiving a high-risk western style diet.

Anti-IgA antibodies in selective IgA deficiency and in primary immunodeficient patients treated with gamma-globulin

Sera from 106 blood donors, 40 patients with primary immunodeficiencies (ID) treated with gamma-globulin, and 46 patients with selective IgA deficiency were analyzed by an enzyme-linked immunosorbent assay for anti-IgA antibodies. Increased levels of antibodies to IgA were found in 5.6% of the blood donors, 17.5% of the ID patients, and 36.8% of the isolated IgA deficiencies. The percentage was higher in patients with IgA and IgG2 deficiencies (50%). The percentage of patients having increased levels of anti-IgA antibodies was similar to the total prevalence of the 10 other autoantibodies studied. These anti-IgA antibodies were mainly of the IgG class, except from one blood donor with IgM antibodies, and two patients, one with isolated IgA deficiency and the other with common variable immunodeficiency who had anti-IgA antibodies of the IgE class. The latter patient developed a near fatal anaphylactic reaction when intravenous gamma-globulin was administered. Most of the patients with severe adverse reactions to gamma-globulin did not present anti-IgA antibodies. Our data suggest that at least in some immunodeficient patients the elevated amounts of anti-IgA antibodies are not related to the administration of exogenous IgA. The importance of measuring anti-IgA antibodies of the IgG and IgE isotypes in IgA-deficient patients as well as in patients in treatment with gamma-globulin is emphasized.

Systematic review with meta-analysis: the risk of major gastrointestinal bleeding with non-vitamin K antagonist oral anticoagulants

BACKGROUND

Gastrointestinal (GI) bleeding is a common complication among anticoagulated patients. Non-vitamin K antagonist oral anticoagulants (NOACs) are associated with increased risk of GI (major and clinically relevant non-major) bleeding. However, more information is needed regarding severe events.

AIM

To evaluate the risk of NOACs major GI bleeding.

METHODS

We searched for phase III randomised clinical trials (RCT) evaluating NOACs (apixaban, dabigatran, edoxaban and rivaroxaban) and reporting major GI bleeding events, in MEDLINE, Cochrane Library, SciELO collection and Web of Science databases (July 2015). Meta-analysis was performed to estimate risk ratio (RR) and 95% confidence intervals (95% CIs). Heterogeneity was assessed with the I(2) test.

RESULTS

A total of 23 studies were included. Among patients with atrial fibrillation, the risk of major GI bleeding was not different between NOACs and vitamin K antagonists (VKA) (RR 1.08, 95% CI 0.85-1.36, I(2)  = 78%; 5 RCTs) or acetylsalicylic acid (RR 0.78, 95% CI 0.36-1.72; 1 RCT). Similar results were found for patients undergoing orthopaedic surgery and those with venous thromboembolism. NOACs were not found to increase the risk compared to low-molecular-weight heparin (LWMH) alone (RR 1.42, 95% CI 0.55-3.71, I(2)  = 7%; 8 RCTs), the sequential treatment with LMWH-VKA (RR 0.77, 95% CI 0.49-1.21, I(2)  = 43%; 7 RCTs) or placebo (RR 1.48, 95% CI 0.15-14.84, I(2)  = 21%; 2 RCTs).

CONCLUSION

Despite previous evidence supporting the association of non-vitamin K antagonist oral anticoagulants and overall GI bleeding, non-vitamin K antagonist oral anticoagulants are not associated with increased risk of major GI bleeding compared to other anticoagulant drugs (with known increased risk of these events).

Diazepam, but not buspirone, induces similar anxiolytic-like actions in lactating and ovariectomized Wistar rats

Previous reports indicate that the behavioural effects (including anxiolytic-like actions, hypothermia, "serotonergic syndrome," maternal behaviour and aggression and reduction in ambulation) of the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), are completely blocked in lactating rats. The present study compares the behavioural effects of buspirone (1.25, 2.5 and 5.0 mg/kg) and diazepam (0.5, 1.0, 2.0 and 4.0 mg/kg) between ovariectomized and mid-lactating rats. The study was carried out on Wistar female rats under inverted light/dark cycle conditions, by using the burying behaviour paradigm, the elevated plus maze and a general activity test. In both ovariectomized and lactating rats, diazepam produced a dose-dependent reduction in burying behaviour and an increase in the time spent in open arms, responses interpreted as anxiolytic. Buspirone at all doses (1.25, 2.5 and 5.0 mg/kg) produced clear motor impairments in lactating, but not in ovariectomized animals, indicating that the effects of this drug on the anxiety paradigms are unspecific. Diazepam, by contrast, at the highest dose (4.0 mg/kg) similarly inhibited ambulation in both conditions. In the elevated plus maze, control lactating subjects spent more time in the open arms compared with saline-treated ovariectomized subjects, suggesting an anxiolytic-like effect of lactation per se. The present results support the idea that some behavioural actions of drugs acting at the serotonergic system vary between ovariectomized and lactating rats.

Muscarinic toxins: novel pharmacological tools for the muscarinic cholinergic system

Muscarinic receptors are widely spread throughout the body, and are involved in the regulation of fundamental physiological processes, like the modulation of the heart rate, control of motor systems and modulation of learning and memory. In the central nervous system the cholinergic transmission is mainly mediated by muscarinic receptors; there are five subtypes that are all expressed in the brain of mammals (m1-m5). There are regional differences in their concentrations in the brain and more than one subtype is expressed in the same cell. It has been difficult to study their localization and function in vivo due to the lack of ligands that exclusively act on one subtype of the receptor. We studied the action of the muscarinic toxins MT1, MT2 and MT3, from the venom of the snake Dendroaspis angusticeps, on muscarinic receptors, by using the classical muscarinic radioligand 3H-NMS as reporter of the inhibition of its own binding, to either native or cloned receptors. We have also studied the in vivo effects on memory retention of the injection of the toxins into discrete brain regions. The muscarinic toxins appear to be invaluable tools to study receptor pharmacology, physiology and structure/function relationships. They would enable the design of new, more selective, pharmacological agents.

Accelerated neuronal differentiation induced by p53 suppression

p53, a tumor suppressor gene product, has been implicated in the control of cell growth and malignant transformation in different cell types. Here we studied the role of p53 in normal central nervous system development. We show that p53 is expressed in neuroblasts and is down regulated when migrating neurons reach their destination. The suppression of p53 either by the addition of antisense oligonucleotides to culture medium or by the culture of neurons from p53-/- mice accelerated their differentiation. This effect is accompanied by an early induction of MAP1b and a premature dephosphorylation of tau. p53 suppression also reduced levels of p21. Taken collectively these results suggest that the expression of p53 in neuroblasts might prevent neuronal terminal differentiation.

Effects of bicuculline infusions in the ventromedial hypothalamus and amygdaloid complex on food intake and affective behavior in mother rats

The mother rat is hyperphagic, aggressive toward other adults, and less fearful than non-maternal rats. The present experiments were conducted to examine whether GABAergic (gamma-aminobutyric acid) mechanisms in the ventromedial hypothalamus and amygdala participate in the control of these behavioral changes. Unilateral infusions of the GABA receptor blocker bicuculline (60 ng/0.5 microliter) into the ventromedial hypothalamus depressed food intake and lowered aggression. Similar infusions into the amygdaloid complex did not affect eating, but they did reduce aggressive behavior. Freezing behavior, a natural fear response, was not affected by the hypothalamic or the amygdaloid bicuculline infusions. These data support previous evidence suggesting a role for GABA in the regulation of postpartum changes in food intake and affective behavior.