Structure of the X-phase of 38% brominated betaine calcium chloride dihydrate

The structures of the high- and low-temperature phases of 38% brominated BCCD [betaine (trimethylammonioacetate) calcium chloride dihydrate], the latter being known as the X-phase, have been determined by single-crystal neutron diffraction at 295 and 20 K, respectively. The symmetry of the X-phase is described by the P212121 space group. The distortion with respect to the high-temperature Pnma phase is characterized by anti-symmetric displacements of the betaine molecules as well as of the Ca octahedra. On the basis of a symmetry-mode analysis, we propose an interpretation of the direct phase transition that occurs around 80 K between these two phases.

Olanzapine reduces urge to drink after drinking cues and a priming dose of alcohol

RATIONALE

Haloperidol, a D2 antagonist, has been shown to moderate the effects of alcohol consumption on craving.

OBJECTIVE

The present study was designed to determine whether a single 5-mg dose of olanzapine (a D2/5-HT2 antagonist) would influence responses to alcohol cues or an alcohol challenge. It was hypothesized that olanzapine would attenuate cue-elicited urge to drink, attenuate the effects of alcohol consumption on urge to drink, and reduce the rewarding effects of alcohol.

METHODS

To test these hypotheses, 26 heavy social drinkers were randomized to receive either 5 mg olanzapine or placebo approximately 8 h before each of two experimental sessions. Participants consumed a moderate dose of alcohol in one experimental session and a non-alcohol control beverage in another session.

RESULTS

Results indicated that mere exposure to alcohol cues and consumption of alcohol increased urge to drink and that olanzapine attenuated these effects. Results also indicated that alcohol increased subjective stimulation and high while olanzapine did not moderate these effects.

CONCLUSIONS

These results suggest that olanzapine did not influence the rewarding effects of alcohol but did attenuate the effects of alcohol cues and an alcohol challenge on urge to drink.

A transient inhibition of mitochondrial ATP synthesis by nitric oxide synthase activation triggered apoptosis in primary cortical neurons

In order to investigate the relationship between nitric oxide-mediated regulation of mitochondrial function and excitotoxicity, the role of mitochondrial ATP synthesis and intracellular redox status on the mode of neuronal cell death was studied. Brief (5 min) glutamate (100 microM) receptor stimulation in primary cortical neurons collapsed the mitochondrial membrane potential (psi(m)) and transiently (30 min) inhibited mitochondrial ATP synthesis, causing early (1 h) necrosis or delayed (24 h) apoptosis. The transient inhibition of ATP synthesis was paralleled to a loss of NADH, which was fully recovered shortly after the insult. In contrast, NADPH and the GSH/GSSG ratio were maintained, but progressively decreased thereafter. Twenty-four hours after glutamate treatment, ATP was depleted, a phenomenon associated with a persistent inhibition of mitochondrial succinate-cytochrome c reductase activity and delayed necrosis. Blockade of either nitric oxide synthase (NOS) activity or the mitochondrial permeability transition (MPT) pore prevented psi(m) collapse, the transient inhibition of mitochondrial ATP synthesis, early necrosis and delayed apoptosis. However, blockade of NOS activity, but not the MPT pore, prevented the inhibition of succinate-cytochrome c reductase activity and delayed ATP depletion and necrosis. From these results, we suggest that glutamate receptor-mediated NOS activation would trigger MPT pore opening and transient inhibition of ATP synthesis leading to apoptosis in a neuronal subpopulation, whereas other groups of neurons would undergo oxidative stress and persistent inhibition of ATP synthesis leading to necrosis.

Reciprocal connections between the medullary dorsal reticular nucleus and the spinal dorsal horn in the rat

The synaptic architecture of spinal afferents of the dorsal portion (DRtd) of the medullary dorsal reticular nucleus (DRt) is studied. After iontophoretic injections of cholera toxin subunit B (CTb) into the superficial (laminae I-II), deep (laminae IV-V) or entire (laminae I-V) dorso-ventral extent of the spinal dorsal horn at the cervico-thoracic or lumbo-sacral levels, axonal boutons of two distinct types were labelled in the DRtd. Type A boutons (82% after cervico-thoracic injections and 92% after lumbo-sacral injections) were roundish, small and presented few mitochondria and small, round synaptic vesicles. Type B boutons (18% after cervico-thoracic injections and 8% after lumbo-sacral injections) were elongated, two to three times larger, and exhibited numerous mitochondria and larger round vesicles. Both types of bouton established asymmetrical synaptic contacts with small dendritic profiles and, less frequently, with dendritic trunks and perikarya. Retrograde labelling occurred in the postsynaptic profile of 15-18% type A boutons labelled from any injection site. Taken together with previous data on DRt-spinal synaptic contacts at the superficial dorsal horn, the present results point to the occurrence of a reciprocal excitatory loop connecting the dorsal DRt and lamina I, which may be at the basis of the DRt-mediated pain-facilitating effects described recently.

Fludarabine-based stem cell transplantation protocol for Fanconi's anaemia in myelodysplastic transformation

Allogeneic stem cell transplantation (SCT) represents the treatment of choice for severe bone marrow (BM) failure in patients with Fanconi's anaemia (FA). However, for FA patients developing leukaemic or myelodysplastic transformation, the results of SCT are much less encouraging. We present a 17-year-old girl with myelodysplastic transformation of FA (refractory anaemia with excess blasts) and oculocutaneous albinism, who was treated by sibling SCT using conditioning with fludarabine, cyclophosphamide (CY) and anti-lymphocyte globulin (ALG). She had rapid engraftment with no toxicity and no graft-versus-host disease (GVHD). Twenty-two months after SCT, she had 100% donor chimaerism on Southern blot analysis.

D-Glucose prevents glutathione oxidation and mitochondrial damage after glutamate receptor stimulation in rat cortical primary neurons

The possible neuroprotective effect of D-glucose against glutamate-mediated neurotoxicity was studied in rat cortical neurons in primary culture. Brief (5-min) exposure of neurons to glutamate (100 microM) increased delayed (24-h) necrosis and apoptosis by 3- and 1.8-fold, respectively. Glutamate-mediated neurotoxicity was accompanied by a D-(-)-2-amino-5-phosphonopentanoate (100 microM) and N(omega)-nitro-L-arginine methyl ester (1 mM)-inhibitable, time-dependent ATP depletion (55% at 24 h), confirming the involvement of NMDA receptor stimulation followed by nitric oxide synthesis in this process. Furthermore, the presence of D-glucose (20 mM), but not its inactive enantiomer, L-glucose, fully prevented glutamate-mediated delayed ATP depletion, necrosis, and apoptosis. Succinate- cytochrome c reductase activity, but not the activities of NADH-coenzyme Q(1) reductase or cytochrome c oxidase, was inhibited by 32% by glutamate treatment, an effect that was abolished by incubation with D-glucose. Lactate accumulation in the culture medium was unmodified by any of these treatments, ruling out the possible involvement of the glycolysis pathway in either glutamate neurotoxicity or D-glucose neuroprotection. In contrast, D-glucose, but not L-glucose, abolished glutamate-mediated glutathione oxidation and NADPH depletion. Our results suggest that NADPH production from D-glucose accounts for glutathione regeneration and protection from mitochondrial dysfunction. This supports the notion that the activity of the pentose phosphate pathway may be an important factor in protecting neurons against glutamate neurotoxicity.

[Teleconsulta en neurology in a health unit: preliminary approach]

This paper begins by discussing the influence of neurological diseases in the practice of general practitioners. A thorough review of the literature allows us to conclude that the frequency of neurological complaints in general practice varies between 7% and 15% and that complaints of sleep disorders reach about 26% in those cases. However, general practitioners do not refer all these neurological cases to a neurologist. They screen the cases and refer only 9% of all observed patients. Next, we briefly analyse the impact of telemedicine in general practice. Given this technique's novelty, we present a predictive model for the utility of teleconsultation, which we are currently developing and testing. We then summarise the current status of general practitioners' referrals to our hospital's neurological outpatient clinic, given previous measures that targeted waiting list reduction and adequate referral. After this overview, we present our methodology, which includes the development and implementation of the technologies needed for teleconsultation and the discussion and application of medical protocols for clinical data, benefits and costs. Simultaneously, we investigated the real need for teleconsultation in Neurology according to the literature and to several, more or less optimistic, models of acceptance. Based on this method, teleconsultation began its regular operation in July 1998. We discuss the result of the first 14 weeks of operation. We observed that referral developed according to calculated predictions and that there were clear advantages regarding diagnostics, medication, exam requests, cost avoidance and patient trips to the central hospital. The data collected predicts that this method is useful, efficient and able to substantially reduce costs.

Illegitimate villin transcripts in normal bone marrow precludes detection of colon cancer micrometastases

Villin is a specific marker for normal and tumoral colon tissue. We have developed a highly sensitive assay using reverse transcription (RT) and real-time PCR to detect villin transcripts. The sensitivity of detection is one colon cancer cell. However, high levels of illegitimate villin transcripts were observed in normal bone marrow, precluding the use of villin RT-PCR for routine detection of colon cancer cells in bone marrow of patients with colon cancer.

Induction of micronuclei by CsCl in vivo and in vitro

In the present study, we report the results of an investigation of the potential of nonradioactive CsCl for the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow and in human lymphocytes cultured and blocked with cytochalasin-B. No significant increase in micronucleus frequency was observed in the polychromatic erythrocytes of mice which received 500 mg/kg of CsCl. In vitro experiments with human lymphocytes cultured in medium containing 250 and 500 micrograms/ml CsCl also showed no increase in micronucleus frequency compared to untreated controls. These same experiments, however, demonstrated a reduction in mitotic activity with increasing CsCl concentration in the culture medium. This report is the first to describe studies on the possible induction of micronuclei in vitro and in vivo by nonradioactive CsCl.

Peroxynitrite anion stimulates arginine release from cultured rat astrocytes

The biosynthesis of the physiological messenger nitric oxide (*NO) in neuronal cells is thought to depend on a glial-derived supply of the *NO synthase substrate arginine. To expand our knowledge of the mechanism responsible for this glial-neuronal interaction, we studied the possible roles of peroxynitrite anion (ONOO-), superoxide anion (O2*-), *NO, and H2O2 in L-[3H]arginine release in cultured rat astrocytes. After 5 min of incubation at 37 degrees C, initial concentrations of 0.05-2 mM ONOO- stimulated the release of arginine from astrocytes in a concentration-dependent way; this effect was maximum from 1 mM ONOO- and proved to be approximately 400% as compared with control cells. ONOO(-)-mediated arginine release was prevented by arginine transport inhibitors, such as L-lysine and N(G)-monomethyl-L-arginine, suggesting an involvement of the arginine transporter in the effect of ONOO-. In situ xanthine/xanthine oxidase-generated O2*- (20 nmol/min) stimulated arginine release to a similar extent to that found with 0.1 mM ONOO-, but this effect was not prevented by arginine transport inhibitors. *NO donors, such as sodium nitroprusside, S-nitroso-N-acetylpenicillamine, or 1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium+ ++-1,2-diolate, and H2O2 did not significantly modify arginine release. As limited arginine availability for neuronal *NO synthase activity may be neurotoxic due to ONOO- formation, our results suggest that ONOO(-)-mediated arginine release from astrocytes may contribute to replenishing neuronal arginine, hence avoiding further generation of ONOO- within these cells.

Nitric oxide mediates brain mitochondrial maturation immediately after birth

The possible role of nitric oxide (*NO) in brain mitochondrial maturation was studied. Within the first 5 min after birth, a sharp increase in ATP concentrations was observed, coinciding with an increase in mitochondrial complex II-III (succinate-cytochrome c reductase) activity, while complex I (NADH-CoQ1 reductase) and complex IV (cytochrome c oxidase) activities remained unchanged. Under the same circumstances, cGMP concentrations were increased by 5 min after birth, correlating significantly with ATP concentrations. Since ATP concentrations also correlated significantly with mitochondrial complex II-III activity, these three parameters may be associated. Inhibition of *NO synthase activity brought about by the administration of N(omega)-nitro-L-arginine monomethyl ester to mothers prevented the postnatal increase in cGMP and ATP levels and complex II-III activity. These results suggest that early postnatal mitochondrial maturation in the brain is a *NO-mediated process.

Roles of nitric oxide in brain hypoxia-ischemia

A large body of evidence has appeared over the last 6 years suggesting that nitric oxide biosynthesis is a key factor in the pathophysiological response of the brain to hypoxia-ischemia. Whilst studies on the influence of nitric oxide in this phenomenon initially offered conflicting conclusions, the use of better biochemical tools, such as selective inhibition of nitric oxide synthase (NOS) isoforms or transgenic animals, is progressively clarifying the precise role of nitric oxide in brain ischemia. Brain ischemia triggers a cascade of events, possibly mediated by excitatory amino acids, yielding the activation of the Ca2+-dependent NOS isoforms, i.e. neuronal NOS (nNOS) and endothelial NOS (eNOS). However, whereas the selective inhibition of nNOS is neuroprotective, selective inhibition of eNOS is neurotoxic. Furthermore, mainly in glial cells, delayed ischemia or reperfusion after an ischemic episode induces the expression of Ca2+-independent inducible NOS (iNOS), and its selective inhibition is neuroprotective. In conclusion, it appears that activation of nNOS or induction of iNOS mediates ischemic brain damage, possibly by mitochondrial dysfunction and energy depletion. However, there is a simultaneous compensatory response through eNOS activation within the endothelium of blood vessels, which mediates vasodilation and hence increases blood flow to the damaged brain area.

DNA content by flow cytometry in gastric carcinoma: pathology, ploidy and prognosis

BACKGROUND/AIMS

The prognostic relevance of histopathologic findings in gastric carcinoma is well established. Studies on DNA-ploidy are still scanty and contradictory.

METHODOLOGY

Histopathologic parameters, DNA ploidy and S-phase were evaluated in 78 cancer patients curatively resected, using formalin-fixed paraffin-embedded tissue.

RESULTS

Thirty-nine tumors (50%) were aneuploid. No significant correlation was found between histologic data and ploidy, but tumors with nodal involvement were more frequently aneuploid. In univariate analysis, tumor location (p=0.05), tumor size (p=0.01), differentiation grade (p=0.02), Lauren classification (p=0.01), deeper infiltration of gastric wall (p=0.001), nodal affectation (p=0.0000) and number of lymph nodes (p=0.01), TNM stage (p=0.0000), type of gastrectomy performed (p=0.04), and DNA ploidy (p=0.04) significantly influenced survival. S-phase values had no effect on prognosis. In the multiple regression model, factors independently associated with survival were TNM stage (p=0.0009), nodal affectation (p=0.01) and, marginally, ploidy (p=0.08).

CONCLUSIONS

In gastric carcinoma curatively resected, the more relevant prognostic factors were stage and nodal involvement. Fifty percent of the tumors were aneuploid. Aneuploidy was significantly associated with poorer prognosis.

Induction of glucose-6-phosphate dehydrogenase by lipopolysaccharide contributes to preventing nitric oxide-mediated glutathione depletion in cultured rat astrocytes

Treatment of cultured rat astrocytes with lipopolysaccharide (LPS; 1 microg/ml) increased mRNA expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting step in the pentose phosphate pathway (PPP), in a time-dependent fashion (0-24 h). This effect was accompanied by an increase in G6PD activity (1.74-fold) and in the rate of glucose oxidation through the PPP (6.32-fold). Inhibition of inducible nitric oxide synthase (iNOS) activity by 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT; 50 microM) did not alter the LPS-mediated enhancement of G6PD mRNA expression or PPP activity. Blockade of nuclear factor-kappaB (NF-kappaB) activation by N-benzyloxycarbonyl-Ile-Glu-(O-tert-butyl)-Ala-leucinal (1 microM) prevented the expression of both iNOS mRNA and G6PD mRNA, suggesting that iNOS and G6PD are co-induced by LPS through a common transcriptional pathway involving NF-kappaB activation. Incubation of cells with LPS for 24 h increased intracellular NADPH concentrations (1.63-fold) as compared with untreated cells, but GSH concentrations were not modified by LPS treatment up to 60 h of incubation. However, inhibition of G6PD activity by dehydroepiandrosterone (DHEA; 100 microM), which prevented LPS-mediated enhancements in PPP activity and NADPH concentrations, caused a 50% decrease in the GSH/GSSG ratio after 24-36 h and in GSH concentrations after 60 h of incubation. Furthermore, the changes in glutathione concentrations caused by DHEA were abolished by AMT, suggesting that nitric oxide and/or its reactive derivatives would be involved in this process. From these results, we conclude that LPS-mediated G6PD expression prevents GSH depletion due to nitric oxide and suggest that this phenomenon may be a contributing factor in the defense mechanisms that protect astrocytes against nitric oxide-mediated cell injury.

Nitric oxide mediates glutamate-induced mitochondrial depolarization in rat cortical neurons

Mitochondria have been considered to be a target for glutamate neurotoxicity. The aim of the present work was to investigate the mechanisms leading to glutamate-mediated mitochondrial deenergization, as measured by mitochondrial membrane potential and cell respiration in cultured neurons. Glutamate exposure to cells induced pronounced mitochondrial depolarization associated with an impairment in neuronal respiration, leading to neuronal ATP depletion. These effects were prevented by both the nitric oxide (. NO) synthase inhibitor Nomega-nitro-l-arginine methyl ester and by the N-methyl-d-aspartate glutamate-subtype receptor inhibitor d-(-)-2-amino-5-phosphopentanoate. Our results suggest that glutamate causes ATP depletion by collapsing mitochondrial membrane potential through a.NO-mediated mechanism.

The medullary dorsal reticular nucleus facilitates pain behaviour induced by formalin in the rat

The influence of the dorsal reticular nucleus (DRt) on pain behaviour during the formalin test was studied in the rat by lesioning the nucleus through local application of electrical current or quinolinic acid. Animals in which the DRt was lesioned ipsilaterally to the paw injected with formalin spent less time in focused (licking, biting or scratching the injected paw) and total (focused pain behaviour plus protection of the injected paw during movements) pain behaviour, and showed paw-jerks less frequently than non-lesioned animals in both phases 1 and 2 of the test. Animals in which the DRt was lesioned contralaterally to the injected paw presented a decrease in total pain behaviour and number of paw-jerks only during phase 2. The number of superficial (laminae I-II) and deep (laminae III-VI) spinal dorsal horn cells expressing the c-fos proto-oncogene 2 h after subcutaneous injection of formalin was reduced by 34% and 50%, respectively, in animals with an ipsilateral DRt lesion as compared to non-lesioned rats. No differences in c-fos expression were observed after lesioning the DRt contralateral to the formalin injection. The results indicate that the DRt is involved in the facilitation of nociception during the formalin test by enhancing the response capacity of dorsal horn neurons to noxious stimulation. It is suggested that the pronociceptive action of the DRt is mediated by the reciprocal connections it establishes with the spinal dorsal horn.

Clinical, cytogenetic and toxicological studies in rural workers exposed to pesticides in Botucatu, São Paulo, Brazil

Pesticides can cause gene mutations and chromosomal aberrations in exposed individuals. We have investigated 24 workers exposed to pesticides. Clinical examinations and cytogenetic and toxicological tests were performed. Ten non-exposed individuals were used as controls. Toxicological dosages of copper, zinc and manganese (metals found in some pesticides), hepatic enzyme dosage (GOT, GPT, AR) and acetylcholinesterase activity were performed in 16 workers and 8 controls. In the exposed workers, the most relevant clinical symptoms were poor digestion with fullness sensation after meals, irritated eyes, headache and fasciculations. The exposed group showed significantly lower manganese dosage and acetylcholinesterase activity, and significantly higher levels of alkaline phosphatase. Cytogenetic studies showed significantly higher chromosomal aberrations in the exposed group compared to the control group. Although the workers used protection against the pesticide's fog, the results revealed that the workers were contaminated with the pesticides. Therefore, the cytogenetic, toxicological studies with clinical examination are necessary for monitoring workers who are exposed to pesticides in any situation.

[CHARGE association]

Posterior choanal atresia is a congenital malformation which can occur isolated or in combination to additional malformations. In CHARGE association the other anomalies are: coloboma, heart disease, retarded development/growth or central nervous system abnormalities, genital hypoplasia or hypogonadism and ear abnormalities or deafness. The authors present three cases of CHARGE association and they also review the clinical findings required for the diagnosis.