Extrastriatal and striatal D(2) dopamine receptor blockade with haloperidol or new antipsychotic drugs in patients with schizophrenia

BACKGROUND

Both traditional and atypical antipsychotics have been hypothesised to be effective in schizophrenia through limbic and cortical D(2) dopamine receptor blockade.

AIMS

To investigate this hypothesis with the D(2)/D(3)-selective positron emission tomography (PET) probe [(76)Br]-FLB457.

METHOD

PET scans were performed on 6 controls and 18 patients with schizophrenia treated with haloperidol or with risperidone, clozapine, amisulpride or olanzapine.

RESULTS

The D(2) dopamine receptor blockade was high in the temporal cortex with both haloperidol and atypical antipsychotics. The atypicals, however, induced a significantly lower D(2) binding index than haloperidol in the thalamus and in the striatum.

CONCLUSIONS

Results suggest that cortical D(2) dopamine receptors are a common target of traditional and atypical antipsychotics for therapeutic action. Higher in vivo binding to the D(2) receptors in the cortex than in the basal ganglia is suggested as an indicator of favourable profile for a putative antipsychotic compound.

Paralytic poliomyelitis associated with the Sabin 3 revertant strain of poliovirus in Bahrain

We report a case of vaccine-associated paralytic poliomyelitis (VAPP) in Bahrain. The case occurred in an 8-week-old infant who had received a dose of oral polio vaccine (OPV) 7 days after birth. She was in contact with two vaccinees who had received OPV during the national immunisation campaign conducted 10 days before her birth. Specimens from the infant were sent to the WHO Collaborating Centre for Virus Reference and Research Laboratory for serological testing and virus detection, including genomic sequencing. Clinical and virological features are presented of a case of VAPP caused by the Sabin 3 strain of poliovirus that had reverted towards neurovirulence. The case represents one in 51,879 first doses of OPV distributed between 1995 and 1998. In order to reduce further the risk of VAPP, the dose of OPV at birth has been discontinued and a sequential schedule of inactivated polio vaccine (IPV) followed by OPV will be recommended.

Cerebral gray and white matter reductions and clinical correlates in patients with early onset schizophrenia

Few magnetic resonance imaging studies of schizophrenia have investigated brain tissue volumes and their relation to clinical symptoms in patients with an early age at illness onset. The twofold purpose of the study was to investigate both gray and white matter volumes in schizophrenic men with an early age at illness onset, and to determine whether clinical features correlated with tissue volume changes, using an automated voxel-by-voxel image analysis procedure. Twenty male patients with DSM-IV diagnoses of schizophrenia, and an early age at onset (m+/-SD=19+/-2) were compared with 20 age-matched health men. Magnetic resonance (1.5-T) scans were obtained with an Inversion-Recovery prepared fast gradient echo sequence enhancing gray and white matter contrast. Statistical Parametric Mapping was used for image segmentation and comparison. Patients had significant gray matter reductions in medial frontal gyri, left insula, left parahippocampus, and left fusiform gyrus; bilateral white matter reductions in frontal lobes, and increased total cerebrospinal fluid volume were also observed. Negative symptom scores were negatively related to white matter volumes in cingulate regions, and in the right internal capsule. These findings emphasize a pattern of left-hemisphere gray matter abnormalities, and suggest that fronto-paralimbic connectivity may be altered in men with early onset schizophrenia.

In vivo extrastriatal and striatal D2 dopamine receptor blockade by amisulpride in schizophrenia

Amisulpride, a substituted benzamide with high affinity for dopamine D2 and D3 receptors only, has been reported to have therapeutic effects on both negative and positive schizophrenic symptoms, although at distinct dose ranges (50-300 mg/day vs. 400-1,200 mg/day). The purpose of this study was to investigate the binding of amisulpride to extrastriatal (i.e., thalamus and temporal cortex) and striatal D2 dopamine receptors with respect to plasma amisulpride determinations. Ten patients with schizophrenia treated with amisulpride over a wide range of doses (25-1,200 mg/day) were studied. Positron emission tomography images were acquired by using 76Br-FLB-457, a highly specific antagonist of the D2 and D3 dopamine receptors. Binding indexes (BI) in the regions studied were estimated with reference to values from six healthy subjects. A curvilinear relationship was demonstrated between plasma concentration of amisulpride and the BI in extrastriatal regions. The BI also varied as a function of plasma concentration in striatum. Furthermore, the data provide evidence for different binding profiles: low plasma concentrations (28-92 ng/mL) induced marked extrastriatal binding and low striatal binding, whereas higher plasma concentrations (>153 ng/mL) induced marked binding both in extrastriatal and striatal regions. Dose-dependent differential binding profiles of amisulpride to D2 receptors in extrastriatal and striatal regions were demonstrated, and two therapeutic ranges of plasma concentrations for negative and positive schizophrenic symptoms, respectively, are suggested.

Adverse events associated with prescription drug cost-sharing among poor and elderly persons

CONTEXT

Rising costs of medications and inequities in access have sparked calls for drug policy reform in the United States and Canada. Control of drug expenditures by prescription cost-sharing for elderly persons and poor persons is a contentious issue because little is known about the health impact in these subgroups.

OBJECTIVES

To determine (1) the impact of introducing prescription drug cost-sharing on use of essential and less essential drugs among elderly persons and welfare recipients and (2) rates of emergency department (ED) visits and serious adverse events associated with reductions in drug use before and after policy implementation.

DESIGN AND SETTING

Interrupted time-series analysis of data from 32 months before and 17 months after introduction of a prescription coinsurance and deductible cost-sharing policy in Quebec in 1996. Separate 10-month prepolicy control and postpolicy cohort studies were conducted to estimate the impact of the drug reform on adverse events.

PARTICIPANTS

A random sample of 93 950 elderly persons and 55 333 adult welfare medication recipients.

MAIN OUTCOME MEASURES

Mean daily number of essential and less essential drugs used per month, ED visits, and serious adverse events (hospitalization, nursing home admission, and mortality) before and after policy introduction.

RESULTS

After cost-sharing was introduced, use of essential drugs decreased by 9.12% (95% confidence interval [CI], 8.7%-9.6%) in elderly persons and by 14.42% (95% CI, 13.3%-15.6%) in welfare recipients; use of less essential drugs decreased by 15.14% (95% CI, 14.4%-15.9%) and 22.39% (95% CI, 20.9%-23.9%), respectively. The rate (per 10 000 person-months) of serious adverse events associated with reductions in use of essential drugs increased from 5.8 in the prepolicy control cohort to 12.6 in the postpolicy cohort in elderly persons (a net increase of 6.8 [95% CI, 5.6-8.0]) and from 14.7 to 27.6 in welfare recipients (a net increase of 12.9 [95% CI, 10.2-15.5]). Emergency department visit rates related to reductions in the use of essential drugs also increased by 14.2 (95% CI, 8.5-19.9) per 10 000 person-months in elderly persons (prepolicy control cohort, 32.9; postpolicy cohort, 47.1) and by 54.2 (95% CI, 33.5-74.8) among welfare recipients (prepolicy control cohort, 69.6; postpolicy cohort, 123.8). These increases were primarily due to an increase in the proportion of recipients who reduced their use of essential drugs. Reductions in the use of less essential drugs were not associated with an increase in risk of adverse events or ED visits.

CONCLUSIONS

In our study, increased cost-sharing for prescription drugs in elderly persons and welfare recipients was followed by reductions in use of essential drugs and a higher rate of serious adverse events and ED visits associated with these reductions.

[Cirrhosis with non alcoholic steatohepatitis: role of tamoxifen]

We report a case of non-alcoholic steatohepatitis with cirrhosis in a woman receiving tamoxifen as adjuvant treatment for breast cancer. Despite the presence of other risk factors for non-alcoholic steatohepatitis (such as diabetes, obesity and hyperlipidemia), the patient developed non-alcoholic steatohepatitis and cirrhosis only after tamoxifen was started. We suggest that patients receiving tamoxifen, especially patients with predisposing metabolic disorders, should be evaluated for non-alcoholic steatohepatitis, because progression to cirrhosis may occur.

Functional cloning of the adenylate cyclase gene of Candida albicans in Saccharomyces cerevisiae within a genomic fragment containing five other genes, including homologues of CHS6 and SAP185

We have cloned a genomic fragment of Candida albicans by complementation of a Saccharomyces cerevisiae cyr1 mutant. This fragment contains the two-thirds C-terminal part of the adenylate cyclase CaCYR1. The complete gene has been sequenced from PCR fragments amplified from genomic DNA, and contains an ORF of 1690 amino acids closely related to other fungal adenylate cyclases. Adjacent to the adenylate cyclase gene, we have sequenced six other putative genes. CaCHS6, CaYNL191 and CaYJL098 are named on the basis of their close similarity with S. cerevisiae genes. ORFs CaYJL097a and CaYJL097b represent two repeated homologues of the S. cerevisiae YJL097w, which probably arose from an ancient duplication. The last one is a hypothetical ORF, CaYKR049, which presents only a very weak similarity with YKR049. The S. cerevisiae homologues of three of these genes are co-localized on chromosome X but with a different order and orientation.

Abnormal psychosocial situations among inpatients from a child and adolescent psychiatric department in a teaching hospital in France

In order to examine the relationships between Associated Abnormal PsychoSocial Situations and psychiatric disorders in children and adolescents, an exploratory analysis using Axis V of the ICD-10 was performed on 1050 child and adolescent psychiatric inpatients. A logistic regression analysis was completed with respect to four groups of DSM-III-R diagnostic categories (Emotional Disorders, Disruptive Behavior Disorders, Specific Developmental Disorders, Non Specific Developmental Disorders). AAPSS were more frequently found in children and adolescents with Emotional Disorders or Disruptive Behavior Disorders than in those with Developmental Disorders but there was no diagnostic specificity in the distribution of AAPSS.

Functional connectivity in depressive, obsessive-compulsive, and schizophrenic disorders: an explorative correlational analysis of regional cerebral metabolism

In order to investigate the changes in functional relationships between brain regions in three psychiatric disorders, an exploratory statistical analysis of the regional cerebral metabolic rates for glucose (rCMRglu) obtained with positron emission tomography (PET) was performed. Correlations between various rCMRglu were computed in control, depressive, obsessive-compulsive, and schizophrenic groups to determine whether alterations of the correlation pattern were found in the psychiatric groups. The absence of correlation between left and right frontal lobes was common to the three psychiatric groups studied. Depressive patients recovered a better frontal interhemispheric coupling after successful treatment and the alterations in the depressed state also involved the relation between the right temporal cortex and the right thalamus. Obsessive-compulsive patients had not only lateral frontal dysfunction but also alterations in the functional relationships between cortex and thalami. In schizophrenic patients, the modifications of regional cerebral metabolic correlations involved both anterior and posterior cortical regions. Thus, although the relationship between left and right frontal lobes was altered in three psychiatric disorders, the pattern of functional connectivity between frontal regions, posterior cortical and subcortical regions differed depending on the diagnostic group.

Indomethacin-induced behavioral changes in an elderly patient with dementia

OBJECTIVE

To describe a case of behavioral changes induced by indomethacin in an elderly man with a history of senile dementia of the Alzheimer type.

CASE SUMMARY

A 92-year-old white man with a history of senile dementia of the Alzheimer type, glaucoma, and constipation was treated with indomethacin for an episode of pseudogout. After six doses of indomethacin 25 mg, the patient became very agitated, confused, and was physically and verbally aggressive to the nurses. Indomethacin was discontinued and the patient recovered after receiving haloperidol 0.5 mg/d p.o. over a period of 10 days.

DISCUSSION

Only a few cases of psychosis have been reported in the literature concerning the use of indomethacin in patients over the age of 60 years. The mechanism by which indomethacin causes psychosis is not well understood, but it is postulated that the acute psychosis may be related to the similarity between the molecular structure of indomethacin and serotonin. Both indomethacin and serotonin have an indolic moiety, which may explain the development of acute psychosis in this patient.

CONCLUSIONS

Healthcare providers should be aware that patients with a history of dementia who are receiving indomethacin may be at risk of developing severe behavior problems along with gastrointestinal and renal adverse effects.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XIV and its evolutionary implications

In 1992 we started assembling an ordered library of cosmid clones from chromosome XIV of the yeast Saccharomyces cerevisiae. At that time, only 49 genes were known to be located on this chromosome and we estimated that 80% to 90% of its genes were yet to be discovered. In 1993, a team of 20 European laboratories began the systematic sequence analysis of chromosome XIV. The completed and intensively checked final sequence of 784,328 base pairs was released in April, 1996. Substantial parts had been published before or had previously been made available on request. The sequence contained 419 known or presumptive protein-coding genes, including two pseudogenes and three retrotransposons, 14 tRNA genes, and three small nuclear RNA genes. For 116 (30%) protein-coding sequences, one or more structural homologues were identified elsewhere in the yeast genome. Half of them belong to duplicated groups of 6-14 loosely linked genes, in most cases with conserved gene order and orientation (relaxed interchromosomal synteny). We have considered the possible evolutionary origins of this unexpected feature of yeast genome organization.

Comparative study of poliovirus excretion after vaccination of infants with two oral polio vaccines prepared on Vero cells or on primary monkey kidney cells

A comparative study was designed to assess the bioequivalence of 2 oral poliovaccines (OPV) produced on 2 different cell systems: primary monkey kidney (PMK) cells and the Vero cell line. The Vero cell line has been used to overcome the problem of obtaining a regular supply of high quality monkeys that are devoid of latent viruses. For this study, 9 children were vaccinated with PMK-OPV and 12 children with Vero-OPV. The comparison covered poliovirus excretion, reversion of polioviruses in the 5'-noncoding region, and immunogenicity. Major molecular markers in the 5'-noncoding region related to neurovirulence already had been identified at position 480 for type 1, position 481 for type 2, and position 472 for type 3 poliovirus. Two nucleic-acid based methods were designed for studying these positions: a RT-PCR followed by sequencing, which required preliminary culture and cloning; and a type-specific nested PCR followed by sequencing, which enabled direct detection and genotyping of polioviruses. Twenty-eight stool specimens were analyzed by this second method with no PCR inhibition problem. The use of Vero cell line did not modify the global pattern of poliovirus excretion, reversion frequency, or seroconversion. These results provide additional support for the use of the well-characterized Vero cell line in OPV manufacturing.

Positional cloning of a gene involved in hereditary multiple exostoses

Hereditary multiple exostosis (EXT) is an autosomal dominant condition mainly characterized by the presence of multiple exostoses on the long bones. These exostoses are benign cartilaginous tumors (enchondromata). Three different EXT loci on chromosomes 8q (EXT1), 11p (EXT2) and 19p (EXT3) have been reported, and recently the EXT1 gene was identified by positional cloning. To isolate the EXT2 gene, we constructed a contig of yeast artificial chromosomes (YAC) and P1 clones covering the complete EXT2 candidate region on chromosome 11p11-p12. One of the transcribed sequences isolated from this region corresponds to a novel gene with homology to the EXT1 gene, and harbours inactivating mutations in different patients with hereditary multiple exostoses. This indicates that this gene is the EXT2 gene. EXT2 has an open reading frame encoding 718 amino acids with an overall homology of 30.9% with EXT1, suggesting that a family of related genes might be responsible for the development of EXT.

Intergenic Flip Flop, a method for systematic gene disruption and cloning in yeast

We have developed a strategy named Intergenic Flip Flop which, for each gene, allows us to produce in one experiment both a disrupting cassette and a plasmid for gap repair. The same method can also be used to insert a reporter gene downstream from the promoter. This approach extends the polymerase chain reaction (PCR)-based strategy proposed by Maftahi et al. 1996. Our method consists of PCR amplification of the two flanking intergenic regions of the open reading frame (ORF) of interest, using two sets of oligonucleotides. Each PCR product is flanked by two short defined nucleotidic sequences with a unique restriction site, allowing subsequent hybridization between them. The association of the two amplimers by the complementary sequences either in the same orientation as in genomic DNA or in the opposite orientation, allows the generation, after PCR, of two distinct cassettes which can be cloned into suitable vectors. When the amplimer in the head-to-tail orientation is cloned in a vector containing a selective marker for yeast such as G418 resistance, it provides a disrupting cassette after cleavage at the unique restriction site introduced by the PCR between the two intergenic amplimers. The amplimer with a direct orientation cloned into a yeast vector, after cleavage at the unique restriction site between the intergenic regions, permits cloning by gap repair of the gene of interest in yeast. Finally, a reporter gene can be inserted in the same plasmid. We report here the successful application of this strategy to an ORF of chromosome XIV of Saccharomyces cerevisiae: N1216.

[Monoamine oxidase inhibitors and food precautions. A comparison of utilization in Belgian psychiatric education institutes and current findings in the literature]

After an extensive survey of MAOI diets prescribed in different Belgian training institutes, there appears to be a confused situation which can cause obstacle for prescription. Of the diets received, we note that 211 foodstuffs and type of foodstuffs have been recommended for restrictive use. However, a most recent literature overviews shows restrictive recommendations for only 40 foodstuffs and types of foodstuffs. Its systematic analysis allows us to propose to the patient a personalized diet with little restrictions which is explained on an understandable rather than a descriptive basis. The adoption of this kind of diet should facilitate easier access to MAOI's, in case more simple therapy strategies have failed, especially in the atypical depressive disorders and tricyclic's refractory depressive disorders.

A 43.5 kb segment of yeast chromosome XIV, which contains MFA2, MEP2, CAP/SRV2, NAM9, FKB1/FPR1/RBP1, MOM22 and CPT1, predicts an adenosine deaminase gene and 14 new open reading frames

A 43,481 bp fragment from the left arm of chromosome XIV of Saccharomyces cerevisiae was sequenced. A gene for tRNA(phe) and 23 non-overlapping open reading frames (ORFs) were identified, seven of which correspond to known yeast genes: MFA2, MEP2, CAP/SRV2, NAM9, FKB1/FPR1/RBP1, MOM22 and CPT1. One ORF may correspond to the yet unidentified yeast adenosine deaminase gene. Among the 15 other ORFs, four exhibit known signatures, which include a protein tyrosine phosphatase, a cytoskeleton-associated protein and two ATP-binding proteins, four have similarities with putative proteins of yeast or proteins from other organisms and seven exibit no significant similarity with amino acid sequences described in data banks. One ORF is identical to yeast expressed sequence tags (EST) and therefore corresponds to an expressed gene. Six ORFs present similarities to human dbESTs, thus identifying motifs conserved during evolution. Nine ORFs are putative transmembrane proteins. In addition, one overlapping and three antisense ORFs, which are not likely to be functional, were detected.

The mitochondrial receptor complex: Mom22 is essential for cell viability and directly interacts with preproteins

A multisubunit complex in the mitochondrial outer membrane is responsible for targeting and membrane translocation of nuclear-encoded preproteins. This receptor complex contains two import receptors, a general insertion pore and the protein Mom22. It was unknown if Mom22 directly interacts with preproteins, and two views existed about the possible functions of Mom22: a central role in transfer of preproteins from both receptors to the general insertion pore or a more limited function dependent on the presence of the receptor Mom19. For this report, we identified and cloned Saccharomyces cerevisiae MOM22 and investigated whether it plays a direct role in targeting of preproteins. A preprotein accumulated at the mitochondrial outer membrane was cross-linked to Mom22. The cross-linking depended on the import stage of the preprotein. Overexpression of Mom22 suppressed the respiratory defect of yeast cells lacking Mom19 and increased preprotein import into mom19 delta mitochondria, demonstrating that Mom22 can function independently of Mom19. Overexpression of Mom22 even suppressed the lethal phenotype of a double deletion of the two import receptors known so far (mom19 delta mom72 delta). Deletion of the MOM22 gene was lethal for yeast cells, identifying Mom22 as one of the few mitochondrial membrane proteins essential for fermentative growth. These results suggest that Mom22 plays an essential role in the mitochondrial receptor complex. It directly interacts with preproteins in transit and can perform receptor-like activities.