Additional booster doses in patients with chronic lymphocytic leukemia induce humoral and cellular immune responses to SARS-CoV-2 similar to natural infection regardless ongoing treatments: A study by ERIC, the European Research Initiative on CLL.

Profound immune dysregulation and impaired response to the SARS-CoV-2 vaccine put patients with chronic lymphocytic leukemia (CLL) at risk of severe COVID-19. We compared humoral memory and T-cell responses after booster dose vaccination or breakthrough infection. (Green) Quantitative determination of anti-Spike specific antibodies. Booster doses increased seroconversion rate and antibody titers in all patient categories, ultimately generating humoral responses similar to those observed in the postinfection cohort. In detail, humoral response with overscale median antibody titers arose in >80% of patients in watch and wait, off-therapy in remission, or under treatment with venetoclax single-agent. Anti-CD20 antibodies and active treatment with BTK inhibitors (BTKi) represent limiting factors of humoral response, still memory mounted in ~40% of cases following booster doses or infection. (Blue) Evaluation of SARS-CoV-2-specific T-cell responses. Number of T-cell functional activation markers documented in each patient. The vast majority of patients, including those seronegative, developed T-cell responses, qualitatively similar between treatment groups or between vaccination alone and infection cases. These data highlight the efficacy of booster doses in eliciting T-cell immunity independently of treatment status and support the use of additional vaccination boosters to stimulate humoral immunity in patients on active CLL-directed treatments.

The structure of chemical vapor deposited graphene substrates for graphene-enhanced Raman spectroscopy.

Defects and nanocrystalline grain structures play a critical role in graphene-enhanced Raman spectroscopy (GERS). In this study, we selected three types of few-layer, polycrystalline graphene films produced by chemical vapor deposition (CVD), and we tested them as GERS substrates. The graphene structure was controlled by decreasing the CVD temperature, thus obtaining (i) polycrystalline with negligible defect density, (ii) polycrystalline with high defect density, (iii) nanocrystalline. We applied rhodamine 6G as a probe molecule to investigate the Raman enhancement. Our results show that nanocrystalline graphene is the most sensitive GERS substrate, indicating that the GERS effect is primarily connected to the nanocrystalline structure, rather than to the presence of defects.

Intrinsic resistance to selumetinib, a selective inhibitor of MEK1/2, by cAMP-dependent protein kinase A activation in human lung and colorectal cancer cells.

BACKGROUND: MEK is activated in ∼40% colorectal cancer (CRC) and 20-30% non-small cell lung cancer (NSCLC). Selumetinib is a selective inhibitor of MEK1/2, which is currently in clinical development. METHODS: We evaluated the effects of selumetinib in vitro and in vivo in CRC and NSCLC cell lines to identify cancer cell characteristics correlating with sensitivity to MEK inhibition. RESULTS: Five NSCLC and six CRC cell lines were treated with selumetinib and classified according to the median inhibitory concentration (IC(50)) values as sensitive (≤1 µM) or resistant (>1 µM). In selumetinib-sensitive cancer cell lines, selumetinib treatment induced G1 cell-cycle arrest and apoptosis and suppression of tumour growth as xenografts in immunodeficient mice. Evaluation of intracellular effector proteins and analysis of gene mutations showed no correlation with selumetinib sensitivity. Microarray gene expression profiles revealed that the activation of cAMP-dependent protein kinase A (PKA) was associated with MEK inhibitor resistance. Combined targeting of both MEK and PKA resulted in cancer cell growth inhibition of MEK inhibitor-resistant cancer cell lines in vitro and in vivo. CONCLUSION: This study provides molecular insights to explain resistance to an MEK inhibitor in human cancer cell lines.

Situational and motivational factors associated with unhealthy alcohol use among Russian women with HIV and hepatitis C Virus co-infection.

Introduction: Alcohol use is prevalent among Russian women with HIV and hepatitis C Virus (HCV) co-infection despite alcohol's known harmful health effects for this population. Identifying factors that facilitate continued unhealthy alcohol use is critical to developing effective alcohol reduction interventions. This study assessed situational and motivational factors associated with unhealthy alcohol use among HIV/HCV co-infected women in clinical care in St. Petersburg, Russia. Methods: Guided by the motivational model for alcohol use, we conducted 30 semi-structured interviews with women living with HIV/HCV co-infection to identify situational and motivational factors associated with unhealthy drinking and barriers and facilitators to abstaining. Interviews were recorded and analyzed using a the-matic analysis approach. Results: Despite awareness of the health risks associated with alcohol use, many women reported heavy episodic drinking, particularly in social situations. A key motive for drinking was coping with negative emotions triggered by stressful situations, such as work- and family-related conflicts. Key situational factors included drinking with family and friends and in social situations. Women who endorsed negative drinking coping motives were the most motivated to stop drinking. Health concerns were also cited as reasons to stop drinking; however, few women reported that their doctors recommended that they abstain. Conclusions: Several situational and motivational facilitators of alcohol use and barriers to alcohol reduction were identified, as well as some opportunities for prevention, among women in care for HIV in Russia. Awareness-raising and training regarding the adverse consequences of alcohol use among persons with HIV/HCV co-infection should include clinicians, patients and relatives.

Gene expression profiling of phytoplasma-infected Madagascar periwinkle leaves using differential display.

Phytoplasmas are small (0.2-0.8 µm), wall-less, pleiomorphic prokaryotes responsible of numerous economically important plant diseases. They are characterized by a very small genome and are obligate parasites of phloem tissues and some insects that act as vectors of infection. To investigate molecular mechanisms involved in pathogenesis, the differential display technique was here applied to identify plant genes whose transcription was significantly altered in leaves of Madagascar periwinkle (Catharanthus roseus (L.) G.Don) infected by 'Candidatus Phytoplasma pyri'. We detected, reamplified, cloned, and sequenced 16 putative differentially expressed cDNA fragments. Northern blot analysis revealed that seven of the 16 genes identified were up-regulated following phytoplasma infection, while three genes were down-regulated. The remaining six genes did not show significant changes in the level of expression. Identified genes are mainly involved in plant defence/stress responses, protein metabolism and transport, transcriptional regulation, vesicle trafficking, and carbohydrate metabolism. The possible role played by these genes in the phytoplasma infection is discussed.

Comparison with naloxone of two dynorphin A analogues with K- and delta-opioid antagonist activity.

Recently, we have demonstrated that substitution of 1,2,3,4 tetrahyidroisoquinoline-3- carboxylic acid (Tic) in place of Gly2 in dynorphin A-(1-13)-NH2 (DYN) analogue (A) decreased the affinity to the kappa, delta, and micro receptors, and kappa selectivity. The doubly substituted analogue [2',6'-dimethyl-L-tyrosine (Dmt1)-Tic2]DYN (B) exhibited high delta-affinity (Ki=0.39 nM) while micro- and kappa-affinities were only an order of magnitude less (4-5 nM). Bioactivity of [Tic2]DYN peptide (A) on guinea-pig ileum and rabbit jejunum revealed potent delta- and kappa-antagonism thus indicating that the conversion from a kappa-agonist to antagonist occurred with the inclusion of Tic into DYN analogues, similar to the appearance of antagonist properties with delta-opioid agonists containing a Tic2 residue. The present study was undertaken to compare the k- and delta-opioid antagonistic activity of two [Tic2] DYN peptides (A and B) with naloxone a well known non selective opioid receptor antagonist. This comparison was performed by using the model of opioid withdrawal in vitro. Following a 4 min in vitro exposure to U50-488 H (10(-8) M), a selective k opioid receptor agonist, the guinea-pig isolated ileum exhibited a strong contracture after the addition of naloxone (10(-5) M). Also, following a 4 min in vitro exposure to deltorphin II (10(-8) M), a selective delta opioid receptor agonist, the rabbit jejunum exhibited a strong contracture after the addition of naloxone (10(-5) M). Results are expressed as percent of Ach contractions. In our study, we showed that in guinea pig ileum the peptide A (k opioid receptor antagonist) was able to induce a strong contracture at a concentration of 10(-9) M when injected 4 min after U50-488H (10(-8) M). Also, in rabbit jejunum the peptide B (delta-opioid receptor antagonist) was able to induce a strong contracture at a concentration of 10(-10) M when injected 4 min after deltorphin II (10(-8) M). The results of our experiments indicate that both peptide A (k receptor opiod antagonist) and peptide B (alpha receptor opioid antagonist) showed an antagonistic activity higher than naloxone.

Characterization of immune responses to anti-PD-1 mono and combination immunotherapy in hematopoietic humanized mice implanted with tumor xenografts.

BACKGROUND: The success of agents that reverse T-cell inhibitory signals, such as anti-PD-1/PD-L1 therapies, has reinvigorated cancer immunotherapy research. However, since only a minority of patients respond to single-agent therapies, methods to test the potential anti-tumor activity of rational combination therapies are still needed. Conventional murine xenograft models have been hampered by their immune-compromised status; thus, we developed a hematopoietic humanized mouse model, hu-CB-BRGS, and used it to study anti-tumor human immune responses to triple-negative breast cancer (TNBC) cell line and patient-derived colorectal cancer (CRC) xenografts (PDX). METHODS: BALB/c-Rag2nullIl2rγnullSIRPαNOD (BRGS) pups were humanized through transplantation of cord blood (CB)-derived CD34+ cells. Mice were evaluated for human chimerism in the blood and assigned into experimental untreated or nivolumab groups based on chimerism. TNBC cell lines or tumor tissue from established CRC PDX models were implanted into both flanks of humanized mice and treatments ensued once tumors reached a volume of ~150mm3. Tumors were measured twice weekly. At end of study, immune organs and tumors were collected for immunological assessment. RESULTS: Humanized PDX models were successfully established with a high frequency of tumor engraftment. Humanized mice treated with anti-PD-1 exhibited increased anti-tumor human T-cell responses coupled with decreased Treg and myeloid populations that correlated with tumor growth inhibition. Combination therapies with anti-PD-1 treatment in TNBC-bearing mice reduced tumor growth in multi-drug cohorts. Finally, as observed in human colorectal patients, anti-PD-1 therapy had a strong response to a microsatellite-high CRC PDX that correlated with a higher number of human CD8+ IFNγ+ T cells in the tumor. CONCLUSION: Hu-CB-BRGS mice represent an in vivo model to study immune checkpoint blockade to human tumors. The human immune system in the mice is inherently suppressed, similar to a tumor microenvironment, and thus allows growth of human tumors. However, the suppression can be released by anti-PD-1 therapies and inhibit tumor growth of some tumors. The model offers ample access to lymph and tumor cells for in-depth immunological analysis. The tumor growth inhibition correlates with increased CD8 IFNγ+ tumor infiltrating T cells. These hu-CB-BRGS mice provide a relevant preclinical animal model to facilitate prioritization of hypothesis-driven combination immunotherapies.

A novel keratinase from Clostridium sporogenes bv. pennavorans bv. nov., a thermotolerant organism isolated from solfataric muds.

A bacterium which can grow on chicken feathers and which exhibits keratinolytic activity was isolated from solfataric muds. It was classified as belonging to the genus Clostridium and closely related to C. sporogenes. Based on its unique capability to degrade chicken feathers, it was designated as Clostridium sporogenes bv. pennavorans bv. nov. The keratinase purified from the culture supernatant is a monomer of 28.7kDa molecular mass. The enzyme is relatively thermostable and is active over a broad range of temperature and pH. Specific enzymatic assays demonstrate that keratinase can act on a large variety of soluble and insoluble protein substrates.

Appropriate intervention strategies for weight gain induced by olanzapine: a randomized controlled study.

Weight gain induced by antipsychotics is the second most frequently given reason for noncompliance with pharmacologic therapy; excessive sedative effects rank first, with extrapyramidal side effects ranking third. Frequently, weight gain leads to inconsistent pharmacologic treatment; this exposes patients to the risk of recurrent symptoms. In fact, one of the key contributors to good clinical outcomes in schizophrenic patients is compliance with pharmacologic treatment. The goals of this study were to evaluate weight gain in a group of patients treated with olanzapine, diet modifications, and moderate physical activity and to compare the findings with those from a second group of patients who were given only olanzapine treatment. For 8 wk, investigators followed 2 groups of patients suffering from schizophrenia and hypomania in bipolar disorder, according to the nosographic criteria of The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The first group (A) of 18 patients (9 female, 9 male) affected by manic episodes in bipolar disorder received olanzapine (10-20 mg/d), jogged lightly for 30 min 3 times a week, and complied with a diet that consisted of 500 kcal/d less than usual. The second group (B) of 10 patients (4 female, 6 male) with schizophrenia received only olanzapine (10-20 mg/d). All patients from both groups were weighed at the beginning of the observation period and weekly thereafter for 2 mo. After 2 mo of observation, group A showed a mean weight gain of 1.47 kg, whereas group B exhibited a mean weight gain of 3.5 kg; the difference between the 2 groups was almost 2 kg (P<.005). Group A showed a statistically significant reduction in weight gain compared with group B, clearly demonstrating the effectiveness of moderate physical activity and diet therapy in reducing weight gain in atypical antipsychotic treatment. Therefore, patient weight and body mass index must be monitored during the first weeks of antipsychotic treatment, with the goals of avoiding significant weight gain and treatment interruption.

The effect of isoquinoline alkaloids on opiate withdrawal.

Our interest has been centered on isoquinoline alkaloids obtained from Argemone mexicana (Papaveraceae), Aristolochia constricta (Aristolochiaceae) and the opium alkaloid, papaverine. In this respect, the effect of these isoquinoline alkaloids was investigated on contractions induced by naloxone of isolated guinea pig ileum acutely exposed to morphine in vitro. The activity of these alkaloids was compared to the control compound, papaverine. Furthermore, the effect of these isoquinoline alkaloids was also determined on naloxone-precipitated withdrawal in isolated guinea pig ileum exposed to DAMGO (highly selective mu opioid receptor agonist) and U50-488H (highly selective kappa opioid receptor agonist) to test whether the possible interaction of isoquinoline alkaloids on opioid withdrawal involves mu- and/or kappa-opioid receptors. Isoquinoline alkaloids from A. mexicana (from 5 x 10(-6) to 1 x 10(-4) M), from A. constricta (1 x 10(-5) x 10(-5)-1 x 10(-4) M) as well as papaverine treatment (1 x 10(-7)-5 x 10(-6)-1 x 10(-6) M) before or after the opioid agonists were able of both preventing and reversing the naloxone-induced contraction after exposure to mu (morphine and DAMGO) or kappa (U50-488H) opiate receptor agonists in a concentration-dependent manner. Both acetylcholine response and electrical stimulation were also reduced by isoquinoline alkaloids and papaverine treatment as well as the final opiate withdrawal was still reduced. The results of the present study indicate that isoquinoline alkaloids as well as papaverine were able to produce significant influence on the opiate withdrawal in vitro and these compounds were able to exert their effects both at mu and kappa opioid agonists.

Subcellular distribution of "intersecting' beta-N-acetylglucosaminyltransferase in Dictyostelium discoideum. A likely marker for the Golgi apparatus.

Glycoprotein processing in Dictyostelium discoideum is characterized by enzyme catalyzed steps not reported in other organisms. One of these is the formation of a beta 1 --> 4 linkage between GlcNAc and the mannose linked to the core mannose in the alpha 1 --> 6 position of N-glycosides. A simple and sensitive assay for this GlcNAc transferase activity, using a tri-mannose acceptor and a low concentration of UDP-GlcNAc, was developed. Homogenates of the organism were subjected to sub-cellular fractionation by centrifugation in discontinuous sucrose gradients. The specific activity was enriched 4-5-fold in a crude membrane fraction. The transferase was purified 10-12-fold in a membrane fraction that bands on top of 1.1 M sucrose. This fraction was also enriched in nucleotidyldiphosphatase. The enriched fraction was deficient in glucose-6-phosphatase, an endoplasmic reticulum marker. Approx. 80% of the transferase activity was latent, and unavailable to protease. Purified membranes were either subjected to phase separation in Triton X-114, or sodium carbonate extraction or sonication. In each case, the transferase behaved as an intrinsic membrane protein. Several secreted and lysosomal proteins are modified by the enzyme. These data support the idea that the GlcNAc transferase is present as an integral Golgi membrane protein and that at least the catalytic center of the transferase is on the lumenal side of the vesicles.

Cathepsin D from the liver of the antarctic icefish Chionodraco hamatus exhibits unusual activity and stability at high temperatures1.

Cathepsin D was purified to homogeneity from the liver of Antarctic icefish by anion-exchange chromatography followed by affinity chromatography on concanavalin-A Sepharose. The purified enzyme showed a molecular mass of 40 kDa and displayed optimal activity at pH 3.0 with a synthetic chromogenic substrate. The N-terminal sequence of this proteinase was determined by automated Edman degradation and was used to design a primer for use in reverse-transcriptase polymerase chain reaction. The open reading frame of the cloned cDNA encoded an aspartic proteinase, which contained the experimentally determined N-terminal sequence. The predicted sequence (396 residues) had a high similarity with those of cathepsin D from various vertebrate sources, but was considerably different from that of nothepsin, a distinct aspartic proteinase described previously from Antarctic fish [1]. Determination of kinetic parameters for substrate hydrolysis showed that, at temperatures between 8 and 50 degrees C, the icefish cathepsin D had a higher specificity constant (kcat/Km) than human cathepsin D. The stability of both enzymes was measured at 50 degrees C and half-lives of 55 and 3 min were derived for icefish and human cathepsin D, respectively.

Treatment of bulimia nervosa with fluvoxamine: a randomized controlled trial.

Bulimia nervosa (BN) is one of the most common eating disorders in industrialized societies. It has been suggested that reduced serotonin activity triggers some of the cognitive and mood disturbances associated with BN. For this reason, the pharmacologic treatment of BN consists mainly of selective serotonin reuptake inhibitors (SSRIs), which have been proven effective. At present, the physiologic bases of this disorder are not yet completely understood. We conducted a randomized controlled trial to verify the efficacy of the SSRI fluvoxamine in patients with a diagnosis of BN. Twelve female outpatients aged 21 to 34 years with a diagnosis of BN-binge purging (as defined by the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders [DSM IV]) were randomly assigned to 2 treatment groups: the fluvoxamine 200 mg/day group and the placebo group. The patients underwent weekly clinical assessments for 12 weeks. At the end of the observation period, there was a statistically significant reduction in the number of binge-eating crises and purging episodes in the fluvoxamine group compared with placebo. In no case was treatment interrupted because of emergent side effects. These findings support the hypothesis that fluvoxamine is well tolerated and effective in reducing binge-eating crises and purging episodes in patients with BN.

Use of sibutramine, an inhibitor of the reuptake of serotonin and noradrenaline, in the treatment of binge eating disorder: a placebo-controlled study.

Binge-eating disorder, which is characterized by repeated episodes of uncontrolled eating, is common in obese patients and is often accompanied by comorbid psychiatric disorders, especially depression. In previous studies, selective serotonin reuptake inhibitors have demonstrated efficacy in reducing the frequency of binge eating and addressing comorbid psychiatric disorders, but they have not shown the ability to promote weight loss. Sibutramine, a new serotonin and norepinephrine reuptake inhibitor, has been shown in short- and long-term studies to be effective in promoting and maintaining weight loss in obese patients who have binge-eating disorder. In this randomized, double-blind, placebo-controlled study, the efficacy, safety, and tolerability of sibutramine were evaluated in the treatment of binge-eating disorder in obese patients. Twenty patients were randomly assigned in equal numbers to receive either sibutramine 10 mg/day or placebo for 12 weeks. Assessments were made at baseline and every 2 weeks throughout the study. Binge frequency, defined as the number of days during the previous week that included binge-eating episodes, was the primary outcome measure. By the end of the study, the binge frequency among patients given sibutramine was significantly lower than that among those given placebo. The main adverse events in the sibutramine group were dry mouth and constipation. The findings suggest sibutramine is an effective medication in the treatment of binge-eating disorders and is well tolerated. In addition, it addresses the 3 main goals in the treatment of binge-eating disorder: reducing the frequency of binge eating, promoting and maintaining weight loss, and treating the comorbid psychiatric conditions.

Design of mu selective opioid dipeptide antagonists.

We have recently designed potent delta selective opioid antagonist dipeptides on the basis of a simple conformational analysis. Following a similar procedure we found a mu selective dipeptide antagonist, 2,6-dimethyl-Tyr-D-Phe-NH2. Although its selectivity is not as high as those of the quoted delta selective dipeptides it has good in vitro activity and looks very promising for further development since the 2,6-dimethyl-Tyr-D-Phe message, like the delta selective 2,6-dimethyl-Tyr-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid counterpart, seems able to impart antagonism to longer peptides.

Further studies on the involvement of the arachidonic acid cascade in the acute dependence produced by mu, kappa and delta opioid agonists in isolated tissues.

The effects of phospholipase A2, cyclooxygenase-1, cyclooxygenase-2, and 5-lipoxygenase inhibitors on acute opiate withdrawal induced by selective mu, kappa and delta receptor agonists was investigated in vitro. After a 4 min in vitro exposure to D-Ala2-N-methyl-Phe-Gly5-ol)enkephalin (DAMGO; a highly selective mu agonist) and trans(+/-)-3,4-dichloro-N-methyl-N-(2(1pyrrolidynyl)-cyclohexyl)-+ ++benzeneacetamid (U50-488H; a highly selective K agonist) a strong contraction of the guinea pig isolated ileum was observed after the addition of naloxone. This effect was also observed when rabbit isolated jejunum was pretreated with deltorphin (a highly selective delta agonist). Mepacrine (a phospholipase A2 inhibitor), tolmetin (a selective cyclooxygenase-1 inhibitor) and meloxicam (a selective cyclooxygenase-2 inhibitor) treatment before or after DAMGO or U50-488H were able to both prevent and reverse the naloxone-induced contraction after exposure to the opioid agonists, in a concentration-dependent fashion. In addition, nordihydroguaiaretic acid (a 5-lipooxygenase inhibitor) was able to block the naloxone-induced contraction following exposure to DAMGO or U50-488H if injected either before or after the opioid agonist. In contrast, mepacrine, tolmetin, meloxicam and nordihydroguaiaretic acid did not affect the naloxone-induced contraction after exposure to deltorphin. The results of the present study confirm and extend a previous study performed with morphine indicating that arachidonic acid and its metabolites (prostaglandins and leukotrienes) are involved in the development of opioid withdrawal induced by selective mu and kappa opioid agonists whereas no effects were observed on withdrawal induced by the selective delta opioid agonist deltorphin.

Synthesis and pharmacological activity of deltorphin and dermorphin-related glycopeptides.

The solid phase procedure, based on the Fmoc chemistry, was used to prepare some opioid deltorphin (H-Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2, DEL C) and dermorphin (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2, DER) analogues in which a D-glucopyranosyl moiety is beta-O-glycosidically linked to a Thr4 or Thr7 side chain. Their activities were determined in binding studies based on displacement of mu- and delta-receptor selective radiolabels from rat brain membrane synaptosomes, in guinea pig ileum and rabbit jejenum bioassays, and, in vivo, by a mouse tail-flick test after intracerebroventricular (icv) and subcutaneous (sc) administrations. The glyco analogues modified at position 4 displayed low opioid properties, while Thr7-glycosylated peptides retained high delta- or mu-selectivity and remarkable activity in vivo. In particular, as systemic antinociceptive agents, the latter glucoside-bearing compounds were more potent than the parent unglycosylated peptide counterparts, showing a high blood to brain rate of influx which may be due to the glucose transporter GLUT-1.

Differential influence of D1 and D2 dopamine receptors on acute opiate withdrawal in guinea-pig isolated ileum.

1. The effects exerted by D1 and D2 dopamine agonists and antagonists on the acute opiate withdrawal induced by mu- and kappa-receptor agonists were investigated in vitro. 2. Following a 4 min in vitro exposure to morphine (moderately selective mu-agonist), [D-Ala2, Me-Phe4, Gly-ol5]enkephalin (DAMGO, highly selective mu-agonist) or U-50488H (highly selective kappa-agonist) the guinea-pig isolated ileum exhibited a strong contracture after the addition of naloxone. 3. The non-selective dopamine receptor antagonist haloperidol when added before or after the opioid agonists, was able dose-dependently to prevent or to reverse the naloxone-induced contracture after exposure to mu- (morphine and DAMGO) and kappa- (U-50488H) opioid agonists. The non-selective dopamine receptor agonist, apomorphine, was able to exert the same effects only at the highest concentration used. 4. The selective D2 dopamine receptor antagonist, sulpiride, was also able to reduce dose-dependently both mu- and kappa-opioid withdrawal, whereas the D1-receptor selective antagonist SCH 23390 did not affect either mu- or kappa-opioid withdrawal. 5. Bromocriptine, a D2 selective dopamine receptor agonist was able to increase significantly, and in a concentration-dependent manner, the naloxone-induced contracture by mu- and kappa-opioid agonists, whereas SKF 38393, a D1 selective dopamine receptor agonist, increased only the withdrawal after morphine or U50-488H. 6. Our data indicate that both D1 and D2 dopamine agonists and antagonists are able to influence opiate withdrawal in vitro, suggesting an important functional interaction between the dopaminergic system and opioid withdrawal at both the mu- and kappa-receptor level. 7. Furthermore, the ability of sulpiride to block strongly opiate withdrawal when compared to SCH 23390, as well as the effect of bromocriptine to increase opiate withdrawal suggest that D2 dopamine receptors may be primarily involved in the control of opiate withdrawal.

Dexamethasone-induced selective inhibition of the central mu opioid receptor: functional in vivo and in vitro evidence in rodents.

1. Endogenous corticosteroids and opioids are involved in many functions of the organism, including analgesia, cerebral excitability, stress and others. Therefore, we considered it important to gain information on the functional interaction between corticosteroids and specific opioid receptor subpopulations. 2. We have found that systemic administration (i.p.) of the potent synthetic corticosteroid, dexamethasone, reduced the antinociception induced by the highly selective mu agonist, DAMGO or by less selective mu agonists morphine and beta-endorphin administered i.c.v.. On the contrary dexamethasone exerted little or no influence on the antinociception induced by a delta 1 agonist, DPDPE and a delta 2 agonist deltorphin II. Dexamethasone potentiated the antinociception induced by the kappa agonist, U50,488. 3. In experiments performed in an in vitro model of cerebral excitability in the rat hippocampal slice, dexamethasone strongly prevented both the increase of the duration of the field potential recorded in CA1, and the appearance and number of additional population spikes induced by mu receptor agonists. 4. In both models pretreatment with cycloheximide, a protein synthesis inhibitor, prevented the antagonism by dexamethasone of responses to the mu opioid agonists. 5. Our data indicate that in the rodent brain there is an important functional interaction between the corticosteroid and the opioid systems at least at the mu receptor level, while delta and kappa receptors are modulated in different ways.

Identification of a high-molecular-weight cadmium-binding protein in copper-resistant Bacillus acidocaldarius cells.

Bacillus acidocaldarius grown in the presence of Cu++ was capable of accumulating the metal in the form of a protease-sensitive high molecular weight (HMW) moiety whose formation was inhibited by actinomycin D. Only cells preadapted in Cu++ were able to grow in a Cd(++)-containing medium. A cell-free extract from cadmium-stressed cells was fractionated by gel-permeation chromatography. The majority of cadmium was found associated with a HMW protein fraction which was further purified by anion exchange chromatography and high-performance liquid chromatography. The molecular weight of the purified protein was estimated to be 23,000 by SDS-PAGE. Amino acid analysis showed a low cysteine content and an abundance of aspartate and glutamate. It is likely that the cadmium-binding protein is an essential component of the mechanism mediating recovery from heavy metal toxicity.