Insights from genomic analysis of a novel Coxiella burnetii strain isolated in Israel

The diagnosis of Q fever is challenging due to nonspecific symptoms and negative standard blood culture results. Serological testing through immunofluorescence assay (IFA) is the most commonly used method for diagnosing this disease. Polymerase chain reaction (PCR) tests can also be used to detect bacterial DNA if taken at an appropriate time. Once the presence of bacteria is confirmed in a sample, an enrichment step is required before characterizing it through sequencing. Cultivating C. burnetii is challenging as it can only be isolated by inoculation into cell culture, embryonated eggs, or animals. In this article, we describe the isolation of C. burnetii from a valve specimen in Vero cells. We conducted genome sequencing and taxonomy profiling of this isolate and were able to determine its taxonomic affiliation. Furthermore, Multispacer sequence typing (MST) analysis suggests that the infection originated from a local strain of C. burnetii found around northern Israel and Lebanon. This novel strain belongs to a previously described genotype MST6, harboring the QpRS plasmid, never reported in Israel.

Enhanced production yields of rVSV-SARS-CoV-2 vaccine using Fibra-Cel® macrocarriers

The COVID-19 pandemic has led to high global demand for vaccines to safeguard public health. To that end, our institute has developed a recombinant viral vector vaccine utilizing a modified vesicular stomatitis virus (VSV) construct, wherein the G protein of VSV is replaced with the spike protein of SARS-CoV-2 (rVSV-ΔG-spike). Previous studies have demonstrated the production of a VSV-based vaccine in Vero cells adsorbed on Cytodex 1 microcarriers or in suspension. However, the titers were limited by both the carrier surface area and shear forces. Here, we describe the development of a bioprocess for rVSV-ΔG-spike production in serum-free Vero cells using porous Fibra-Cel® macrocarriers in fixed-bed BioBLU®320 5p bioreactors, leading to high-end titers. We identified core factors that significantly improved virus production, such as the kinetics of virus production, the use of macrospargers for oxygen supply, and medium replenishment. Implementing these parameters, among others, in a series of GMP production processes improved the titer yields by at least two orders of magnitude (2e9 PFU/mL) over previously reported values. The developed process was highly effective, repeatable, and robust, creating potent and genetically stable vaccine viruses and introducing new opportunities for application in other viral vaccine platforms.

Monkeypox DNA levels correlate with virus infectivity in clinical samples, Israel, 2022

The current monkeypox virus global spread and lack of data regarding clinical specimens' infectivity call for examining virus infectivity, and whether this correlates with results from PCR, the available diagnostic tool. We show strong correlation between viral DNA amount in clinical specimens and virus infectivity toward BSC-1 cell line. Moreover, we define a PCR threshold value (Cq ≥ 35, ≤ 4,300 DNA copies/mL), corresponding to negative viral cultures, which may assist risk-assessment and decision-making regarding protective-measures and guidelines for patients with monkeypox.

Centaur antibodies: Engineered chimeric equine-human recombinant antibodies

Hyper-immune antisera from large mammals, in particular horses, are routinely used for life-saving anti-intoxication intervention. While highly efficient, the use of these immunotherapeutics is complicated by possible recipient reactogenicity and limited availability. Accordingly, there is an urgent need for alternative improved next-generation immunotherapies to respond to this issue of high public health priority. Here, we document the development of previously unavailable tools for equine antibody engineering. A novel primer set, EquPD v2020, based on equine V-gene data, was designed for efficient and accurate amplification of rearranged horse antibody V-segments. The primer set served for generation of immune phage display libraries, representing highly diverse V-gene repertoires of horses immunized against botulinum A or B neurotoxins. Highly specific scFv clones were selected and expressed as full-length antibodies, carrying equine V-genes and human Gamma1/Lambda constant genes, to be referred as “Centaur antibodies”. Preliminary assessment in a murine model of botulism established their therapeutic potential. The experimental approach detailed in the current report, represents a valuable tool for isolation and engineering of therapeutic equine antibodies.

Fc-Independent Protection from SARS-CoV-2 Infection by Recombinant Human Monoclonal Antibodies

The use of passively-administered neutralizing antibodies is a promising approach for the prevention and treatment of SARS-CoV-2 infection. Antibody-mediated protection may involve immune system recruitment through Fc-dependent activation of effector cells and the complement system. However, the role of Fc-mediated functions in the efficacious in-vivo neutralization of SARS-CoV-2 is not yet clear, and it is of high importance to delineate the role this process plays in antibody-mediated protection. Toward this aim, we have chosen two highly potent SARS-CoV-2 neutralizing human monoclonal antibodies, MD65 and BLN1 that target distinct domains of the spike (RBD and NTD, respectively). The Fc of these antibodies was engineered to include the triple mutation N297G/S298G/T299A that eliminates glycosylation and the binding to FcγR and to the complement system activator C1q. As expected, the virus neutralization activity (in-vitro) of the engineered antibodies was retained. To study the role of Fc-mediated functions, the protective activity of these antibodies was tested against lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice, when treatment was initiated either before or two days post-exposure. Antibody treatment with both Fc-variants similarly rescued the mice from death reduced viral load and prevented signs of morbidity. Taken together, this work provides important insight regarding the contribution of Fc-effector functions in MD65 and BLN1 antibody-mediated protection, which should aid in the future design of effective antibody-based therapies.

Therapeutic antibodies, targeting the SARS-CoV-2 spike N-terminal domain, protect lethally infected K18-hACE2 mice

Neutralizing antibodies represent a valuable therapeutic approach to countermeasure the current COVID-19 pandemic. Emergence of SARS-CoV-2 variants emphasizes the notion that antibody treatments need to rely on highly neutralizing monoclonal antibodies (mAbs), targeting several distinct epitopes for circumventing therapy escape mutants. Previously, we reported efficient human therapeutic mAbs recognizing epitopes on the spike receptor-binding domain (RBD) of SARS-CoV-2. Here we report the isolation, characterization, and recombinant production of 12 neutralizing human mAbs, targeting three distinct epitopes on the spike N-terminal domain of the virus. Neutralization mechanism of these antibodies involves receptors other than the canonical hACE2 on target cells, relying both on amino acid and N-glycan epitope recognition, suggesting alternative viral cellular portals. Two selected mAbs demonstrated full protection of K18-hACE2 transgenic mice when administered at low doses and late post-exposure, demonstrating the high potential of the mAbs for therapy of SARS-CoV-2 infection.

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Isolation of potent neutralizing antibodies, targeting the NTD of SARS-CoV-2

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Involvement of both protein and glycan moieties in antibody binding was suggested

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Post-exposure protection of lethally infected K18-hACE2 mice by BLN12 and BLN14

Post-exposure protection of SARS-CoV-2 lethal infected K18-hACE2 transgenic mice by neutralizing human monoclonal antibody

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), exhibits high levels of mortality and morbidity and has dramatic consequences on human life, sociality and global economy. Neutralizing antibodies constitute a highly promising approach for treating and preventing infection by this novel pathogen. In the present study, we characterize and further evaluate the recently identified human monoclonal MD65 antibody for its ability to provide protection against a lethal SARS-CoV-2 infection of K18-hACE2 transgenic mice. Eighty percent of the untreated mice succumbed 6-9 days post-infection, while administration of the MD65 antibody as late as 3 days after exposure rescued all infected animals. In addition, the efficiency of the treatment is supported by prevention of morbidity and ablation of the load of infective virions in the lungs of treated animals. The data demonstrate the therapeutic value of human monoclonal antibodies as a life-saving treatment for severe COVID-19 infection.

Comparative Analysis of the Global Transcriptomic Response to Oxidative Stress of Bacillus anthracis htrA-Disrupted and Parental Wild Type Strains

We previously demonstrated that the HtrA (High Temperature Requirement A) protease/chaperone active in the quality control of protein synthesis, represents an important virulence determinant of Bacillus anthracis. Virulence attenuation of htrA-disrupted Bacillus anthracis strains was attributed to susceptibility of ΔhtrA strains to stress insults, as evidenced by affected growth under various stress conditions. Here, we report a comparative RNA-seq transcriptomic study generating a database of differentially expressed genes in the B. anthracishtrA-disrupted and wild type parental strains under oxidative stress. The study demonstrates that, apart from protease and chaperone activities, HtrA exerts a regulatory role influencing expression of more than 1000 genes under stress. Functional analysis of groups or individual genes exhibiting strain-specific modulation, evidenced (i) massive downregulation in the ΔhtrA and upregulation in the WT strains of various transcriptional regulators, (ii) downregulation of translation processes in the WT strain, and (iii) downregulation of metal ion binding functions and upregulation of sporulation-associated functions in the ΔhtrA strain. These modulated functions are extensively discussed. Fifteen genes uniquely upregulated in the wild type strain were further interrogated for their modulation in response to other stress regimens. Overexpression of one of these genes, encoding for MazG (a nucleoside triphosphate pyrophosphohydrolase involved in various stress responses in other bacteria), in the ΔhtrA strain resulted in partial alleviation of the H₂O₂-sensitive phenotype.

Evaluating the efficacy of RT-qPCR SARS-CoV-2 direct approaches in comparison to RNA extraction

The genetic identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is based on viral RNA extraction prior to RT-qPCR assay. However, recent studies have supported the elimination of the extraction step. This study was performed to assess the necessity for the RNA extraction, by comparing the efficacy of RT-qPCR in several direct approaches versus the gold standard RNA extraction, in the detection of SARS-CoV-2 in laboratory samples, as well as in clinical oro-nasopharyngeal SARS-CoV-2 swabs. The findings showed an advantage for the extraction procedure; however a direct no-buffer approach might be an alternative, since it identified more than 60% of positive clinical specimens.

A rapid high-throughput sequencing-based approach for the identification of unknown bacterial pathogens in whole blood

High-throughput DNA sequencing (HTS) of pathogens in whole blood samples is hampered by the high host/pathogen nucleic acids ratio. We describe a novel and rapid bacterial enrichment procedure whose implementation is exemplified in simulated bacteremic human blood samples. The procedure involves depletion of the host DNA, rapid HTS and bioinformatic analyses. Following this procedure, Y. pestis, F. tularensis and B. anthracis spiked-in samples displayed an improved host/pathogen DNA ratio of 2.5-5.9 orders of magnitude, in samples with bacteria spiked-in at 103-105 CFU/ml. The procedure described in this study enables rapid and detailed metagenomic profiling of pathogens within 8-9 h, circumventing the challenges imposed by the high background present in the bacteremic blood and by the unknown nature of the sample.

Case Report: Imported Melioidosis from Goa, India to Israel, 2018

A previously healthy young man presented with a chronic cavitary pulmonary infection that began while in Goa, India. Burkholderia pseudomallei was cultured from sputum samples. The infection fully resolved after prolonged antibiotic treatment. Other than traveling during the monsoon season, extensive use of well-water for water-pipe smoking of cannabis was identified as a possible risk factor for infection. This is one of the first reports of travel-associated melioidosis from India. Genomic and immunological characterization suggested that the B. pseudomallei isolate collected from the reported case exhibited limited similarity to other B. pseudomallei strains.

Rapid identification of unknown pathogens in environmental samples using a high-throughput sequencing-based approach

In the event of a bioterror attack, a prompt, sensitive and definite identification of the agents involved is of major concern for confirmation of the event and for mitigation of countermeasures. Whether the information from intelligence forces is limited concerning the biothreat identity or one suspects the presence of a novel or engineered agent, the genetic identification of microorganisms in an unknown sample is challenging. High-throughput sequencing (HTS) technologies can sequence a heterogeneous mixture of genetic materials with high sensitivity and speed; nevertheless, despite the enormous advantages of HTS, all previous reports have analyzed unknown samples in a timeframe of a few days to a few weeks. This timeframe might not be relevant to an emergency scenario. Here, we present an HTS-based approach for deciphering the genetic composition of unknown samples within a working day. This outcome is accomplished by a rapid library preparation procedure, short-length sequencing and a prompt bioinformatics comparison against all available microbial genomic sequences. Using this approach, as a proof of concept, we were able to detect two spiked-in biothreat agents, B. anthracis and Y. pestis, in a variety of environmental samples at relevant concentrations and within a short timeframe of eight hours.

TREATMENTS OF HEPATITIS C VIRUS LIVER CIRRHOSIS WITH PEGYLAT INTERFERON-RIBAVIRIN AND INTERFERON FREE – COMPARATIVE STUDY

The article describes the adverse effects and efficiency of hepatitis C virus liver cirrhosis treatments available through the National Health Insurance Services, on a population of patients hospitalized at Victor Babes Infectious and Tropical Diseases Hospital, from 2012 to 2016. The population of patients was split into two distinct groups, for which we’ve recorded and comparatively analyzed demographic, clinical and paraclinical characteristics in a database. An evident success was recorded, from the point of view of hitting a clinical SVR index, in the DAA therapy group A, 87% percent compared to 2% in group B for the traditional standard therapy of PegInterferon + Ribavirin. Likewise, the number of adverse effects was lower in Group B versus Group A. Some side effects remained specific to the current cirrhosis treatment, which should be closely monitored.

T cells play an essential role in anti-F1 mediated rapid protection against bubonic plague

Plague, which is initiated by Yersinia pestis infection, is a fatal disease that progresses rapidly and leads to high mortality rates if not treated. Antibiotics are an effective plague therapy, but antibiotic-resistant Y. pestis strains have been reported and therefore alternative countermeasures are needed. In the present study, we assessed the potential of an F1 plus LcrV-based vaccine to provide protection shortly pre- or post-exposure to a lethal Y. pestis infection. Mice vaccinated up to one day before or even several hours after subcutaneous challenge were effectively protected. Mice immunized one or three days pre-challenge were protected even though their anti-F1 and anti-LcrV titers were below detection levels at the day of challenge. Moreover, using B-cell deficient μMT mice, we found that rapidly induced protective immunity requires the integrity of the humoral immune system. Analysis of the individual contributions of vaccine components to protection revealed that rF1 is responsible for the observed rapid antibody-mediated immunity. Applying anti-F1 passive therapy in the mouse model of bubonic plague demonstrated that anti-F1 F(ab')(2) can delay mortality, but it cannot provide long-lasting protection, as do intact anti-F1 molecules. Fc-dependent immune components, such as the complement system and (to a lesser extent) neutrophils, were found to contribute to mouse survival. Interestingly, T cells but not B cells were found to be essential for the recovery of infected animals following passive anti-F1 mediated therapy. These data extend our understanding of the immune mechanisms required for the development of a rapid and effective post-exposure therapy against plague.

P01-341-Socialization aspects in children with stuttering

Stuttering, as a communication disorder, is a field of great interest, with many hypothesis regarding its nature and appropriate treatment. Many studies tried to emphasize the bond between stuttering and anxiety. Frequently, stuttering is associated with strong emotional reaction, as anxiety, emphasized by negative consequences of “not being able to talk accurately”. This turns in avoidance of speak and social problems as school difficulties.

The aim of this study is anxiety evaluation in children with stuttering through specialized psychological intervention.

We applied MASC (Multidimensional Anxiety Scale for Children) and CDI (Child Depression Inventory) to 20 children diagnosed with stuttering, aged 6–16, from Cluj -Napoca, both at the beginning and at the end of the study. Psychological intervention consisted of two evaluation sessions (one with the parent and one with the child) and ten group sessions (psychodrama and cognitive-behavioral techniques).

The results showed a significant decrease of anxiety (p < 0.05), and no difference in depression symptoms (for statistical data we used SPSS 16.0 Program).

Detection of single atoms and buried defects in three dimensions by aberration-corrected electron microscope with 0.5-A information limit

The ability of electron microscopes to analyze all the atoms in individual nanostructures is limited by lens aberrations. However, recent advances in aberration-correcting electron optics have led to greatly enhanced instrument performance and new techniques of electron microscopy. The development of an ultrastable electron microscope with aberration-correcting optics and a monochromated high-brightness source has significantly improved instrument resolution and contrast. In the present work, we report information transfer beyond 50 pm and show images of single gold atoms with a signal-to-noise ratio as large as 10. The instrument's new capabilities were exploited to detect a buried Sigma3 {112} grain boundary and observe the dynamic arrangements of single atoms and atom pairs with sub-angstrom resolution. These results mark an important step toward meeting the challenge of determining the three-dimensional atomic-scale structure of nanomaterials.

Neutralization of Yersinia pestis-mediated macrophage cytotoxicity by anti-LcrV antibodies and its correlation with protective immunity in a mouse model of bubonic plague

Plague is a life-threatening disease caused by Yersinia pestis, for which effective-licensed vaccines and reliable predictors of in vivo immunity are lacking. V antigen (LcrV) is a major Y. pestis virulence factor that mediates translocation of the cytotoxic Yersinia protein effectors (Yops). It is a well-established protective antigen and a part of currently tested plague subunit vaccines. We have developed a highly sensitive in vitro macrophage cytotoxicity neutralization assay which is mediated by anti-LcrV antibodies; and studied the potential use of these neutralizing antibodies as an in vitro correlate of plague immunity in mice. The assay is based on a Y. pestis strain with enhanced cytotoxicity to macrophages in which endogenous yopJ was replaced by the more effectively translocated yopP of Y. enterocolitica O:8. Mice passively immunized with rabbit anti-LcrV IgG or actively immunized with recombinant LcrV were protected against lethal doses of a virulent Y. pestis strain, in a mouse model of bubonic plague. This protection significantly correlated with the in vitro neutralizing activity of the antisera but not with their corresponding ELISA titers. In actively immunized mice, a cutoff value for serum neutralizing activity, above which survival was assured with high degree of confidence, could be established for different vaccination regimes. The impact of overall findings on the potential use of serum neutralizing activity as a correlate of protective immunity is discussed.

Enhancement of resolution in core-loss and low-loss spectroscopy in a monochromated microscope

The significant enhancement of the energy resolution in the new generation of commercially available monochromated transmission electron microscopes presents new challenges in term of selecting the correct experimental conditions and understanding the various effects that can potentially influence the quality of the EELS data. In this respect we investigated the effect of point spread function of the detector and spectrum-diffraction mixing on the energy resolution and the intensity of the zero loss peak tails. Alternative approaches to improve the energy resolution by mathematical methods have been tested. By using a simple and commonly available test case (Si L(2,3) edges) we assessed the efficiency of the deconvolution algorithms to improve the resolution. The results show that the deconvolution is not always successful in improving the resolution of the core loss EELS data and the results may not always be reliable. Contrary to this, the application of the Richardson-Lucy deconvolution algorithm on some bandgap measurements data appears to be very effective. The procedure proved successful in removing the contribution of the zero-loss peak tails and allows an easier access to spectroscopic information starting at energy losses as low as of 0.5 eV with monochromated spectra and 1 eV with the non-monochromated spectra.

Angular and Local Spectroscopic Analysis to Probe the Vertical Alignment of N-doped Well-separated Carbon Nanotubes

Vertically aligned well-separated N-doped multiwalled carbon nanotubes (CNTs) were grown on a silicon substrate by plasma enhanced chemical vapor deposition (PECVD). Angular near-edge X-ray absorption fine structure (NEXAFS) was used to investigate the vertical alignment of as-grown CNTs. In addition, both individual tubes and tube bundles were characterized by high-resolution electron energy loss spectroscopy (HREELS). Simultaneous analysis of both spectroscopic techniques provides information on chemical environment, orbital orientation between carbon and heteroatoms, and local curvature effects. We demonstrate the utility of NEXAFS as an in situ probe of CNTs.

Čerenkov losses: A limit for bandgap determination and Kramers–Kronig analysis

Measuring low energy losses in semiconductors and insulators with high spatial resolution becomes attractive with the increasing availability of modern transmission electron microscopes (TEMs) equipped with monochromators, C(s) correctors and energy filters. In this paper, we demonstrate that Cerenkov losses pose a limit for the interpretation of low energy loss spectra (EELS) in terms of interband transistions and bandgap determination for many materials. If the velocity of a charged particle in a medium exceeds the velocity of light, photons are emitted leading to a corresponding energy loss of a few electronvolt. Since these losses are strong for energies below the onset of interband transitions, they change the apparent loss function of semiconductors and insulators, with the risk of erroneous interpretation of spectra. We measured low energy losses of Si and GaAs with a monochromated TEM demonstrating the effect of sample thickness on Cerenkov losses. Angle resolved EELS and energy filtered diffraction patterns (taken without a monochromator) show the extremely narrow angular distribution of Cerenkov losses. The latter experiment provides a method that allows to decide whether Cerenkov radiation masks the very low loss signal in EELS.

Generation of Yersinia pestis attenuated strains by signature-tagged mutagenesis in search of novel vaccine candidates

In a search for novel attenuated vaccine candidates for use against Yersinia pestis, the causative agent of plague, a signature-tagged mutagenesis strategy was used and optimized for a subcutaneously infected mouse model. A library of tagged mutants of the virulent Y. pestis Kimberley53 strain was generated. Screening of 300 mutants through two consecutive cycles resulted in selection of 16 mutant strains that were undetectable in spleens 48 h postinfection. Each of these mutants was evaluated in vivo by assays for competition against the wild-type strain and for virulence following inoculation of 100 CFU (equivalent to 100 50% lethal doses [LD50] of the wild type). A wide spectrum of attenuation was obtained, ranging from avirulent mutants exhibiting competition indices of 10(-5) to 10(-7) to virulent mutants exhibiting a delay in the mean time to death or mutants indistinguishable from the wild type in the two assays. Characterization of the phenotypes and genotypes of the selected mutants led to identification of virulence-associated genes coding for factors involved in global bacterial physiology (e.g., purH, purK, dnaE, and greA) or for hypothetical polypeptides, as well as for the virulence regulator gene lcrF. One of the avirulent mutant strains (LD50, >10(7) CFU) was found to be disrupted in the pcm locus, which is presumably involved in the bacterial response to environmental stress. This Kimberley53pcm mutant was superior to the EV76 live vaccine strain because it induced 10- to 100-fold-higher antibody titers to the protective V and F1 antigens and because it conferred efficacious protective immunity.

Enantioselective synthesis of 2- and 3-substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine derivatives and enantiomeric purity control by capillary electrophoresis

A rapid and simple procedure for enantioselective preparation of 2- and 3-substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine derivatives (A and B, respectively) is described. The enantiomeric purity of each isomer was determined by capillary electrophoresis using a dual-cyclodextrin system (S-beta-CD/beta-CD) dissolved in formic acid-ammonia buffer (pH 4, ionic strength 50 mM).

Investigation of hexagonal and cubic GaN by high-resolution electron energy-loss spectroscopy and density functional theory

High-resolution electron energy-loss spectroscopy in a transmission electron microscope is a very powerful method for the study of electronic structure of materials. The fine structure of Ga L(2,3) and N ionization edges in c-GaN and h-GaN was studied using a TEM equipped with a monochromator and high-resolution energy spectrometer. The experimental results were compared with the results of calculation based on the density functional theory using the Wien2k code and show that the best fit is achieved when the core hole effect is taken into account. The effect of the core hole value and the supercell size on the energy-loss near-edge structure have been investigated. A different behaviour was found for c-GaN and h-GaN: better agreement is obtained for a 0.5 core hole for h-GaN and for a full core hole for c-GaN. The anisotropic behaviour of the experimental spectra and calculated spectra for h-GaN have been studied and the "magic" angle was determined.

Materials science applications of HREELS in near edge structure analysis and low-energy loss spectroscopy

New experiments made possible with a commercial transmission electron microscope (TEM) equipped with a high-resolution electron energy loss spectrometer (EELS) are presented. With this commercial system, a 100 meV energy resolution using a sub 2 nm probe or 500 meV at a 0.20 nm probe are possible, in combination with other modern techniques available for TEMs. In this paper a number of explorative examples of the first results are shown. The benefit of the increased resolution for detecting more details in near edge structures are shown for the Ti K edge in TiO(2) (brookite) and for the N K edge in cubic and hexagonal GaN. The bandgap of GaN is studied in both crystal structures, as well as the dependency of the low-loss spectrum on the momentum transfer direction in diffraction mode.

Atypical antipsychotic use in treating adolescents and young adults with developmental disabilities

OBJECTIVE

To study the usage, efficacy, and side effects patterns of atypical neuroleptics (atypicals) in adolescents and young adults with developmental disabilities (DDs) (mental retardation).

METHOD

We undertook a chart review of adolescents and young adults (under age 25 years) seen by our specialized mental health team.

RESULTS

Risperidone and olanzapine were by far the most frequently prescribed atypicals. Robust clinical effects were noted for both psychotic and nonpsychotic disorders. Most patients tolerated atypicals well, although a significant minority did experience neuroleptic induced movement disorders (NIMDs), particularly dystonias and dyskinesias. Female patients with DDs appear to be at particular risk of NIMDs.

CONCLUSIONS

Atypicals are useful in treating various conditions associated with DDs. This population, however, seems particularly sensitive to NIMDs, hence caution and close monitoring are required.

Role of meiosis-activating sterols in rat oocyte maturation: effects of specific inhibitors and changes in the expression of lanosterol 14alpha-demethylase during the preovulatory period

In vitro studies on mouse oocytes have shown that two closely related sterols, subsequently named meiosis-activating sterols (MAS), can overcome the inhibitory effect of hypoxanthine on the resumption of meiosis. These sterols are synthesized by cytochrome P(450) lanosterol 14alpha-demethylase (LDM), a key enzyme in cholesterol biosynthesis. We have used specific inhibitors of LDM, azalanstat (RS-21607) and RS-21745, to test whether MAS is an obligatory mediator in the resumption of meiosis in the rat. Addition of azalanstat and RS-21745 (1-200 microM) to culture medium of rat isolated cumulus-enclosed oocyte and preovulatory follicle-enclosed oocyte stimulated by LH/hCG did not allow separation between their inhibition of the resumption of meiosis and the degeneration of oocytes. In both models, doses of the drug that inhibited oocyte maturation also increased oocyte degeneration. The inhibitors only partially suppressed follicular progesterone production. We have examined by reverse transcriptase-polymerase chain reaction, Western blotting, and immunocytochemistry the ovarian expression of LDM mRNA and protein during the preovulatory period. We did not find evidence for the stimulation of this enzyme by LH/hCG. The strongest staining by LDM antiserum was obtained in primordial and primary oocytes, and the staining was reduced with oocyte growth. In addition, strong LDM staining could be observed in some of the granulosa cells, especially of the corona radiata localized in close proximity to the oocyte. In conclusion, our results with specific inhibitors and molecular approaches do not reveal evidence to support the hypothesis that MAS is an obligatory step in the stimulation of the resumption of meiosis. Specific inhibitors of MAS synthesis did not prevent spontaneous or LH-stimulated meiosis at doses that have previously been shown to effectively suppress LDM activity. Much higher concentrations of the inhibitors, which affected meiosis, were detrimental to oocytes, leading to their degeneration. The timing of LDM expression in the ovary was incompatible with a role for MAS in meiosis. Finally, the preferential localization of LDM protein to the oocytes suggests MAS production in oocytes rather than its transport from the somatic compartment as implied by the proposed role of MAS as a cumulus-oocyte signal molecule.

Synthesis of 2-substituted-2,3- dihydro-1,4-dioxino[2,3-b]pyridine derivatives

[reaction--see text] A variety of 2-substituted-2,3-dihydro-1,4-dioxino[2,3-b]pyridines B have been synthesized from the readily available 2-nitro-3-oxiranylmethoxypyridine 1 via a Smiles rearrangement. We demonstrate how variations of reaction conditions affect the product distribution of A and B.

ToxR-independent expression of cholera toxin from the replicative form of CTXphi

The ctxAB operon, which encodes cholera toxin, resides in the genome of CTXphi, a filamentous bacteriophage. Within Vibrio cholerae cells, the CTXphi genome can exist either as a replicating plasmid or as a prophage integrated into the chromosome. Previous work established that ToxR is required for chromosomal ctxAB expression. We have learned that strains harboring the CTXphi replicative form produce cholera toxin under all conditions tested, independently of ToxR. During passage of CTXphi lysogens through the infant mouse intestine, transduction of CTXphi to a recipient strain can be detected, indicating that phage excision and replication occur in vivo. These results suggest that phage induction might provide a novel mechanism for the regulation of cholera toxin production.