Biomedical subjects

M Loyer

Publications and source records attributed to M Loyer.

9 recordsLinked to original sources

PubMed1997

Clinical specificity of prison inmates with severe mental disorders. A case-control study.

BACKGROUND: We wished to determine whether prison inmates with severe mental disorders possess specific clinical characteristics compared with psychiatric in-patients suffering from similar problems. METHOD: Under a case-control design, 69 male prison inmates suffering from a schizophrenic or major affective disorder were matched for age and diagnostic spectrum to 60 male psychiatric in-patients. Standardised interviews were used to diagnose psychiatric disorders according to DSM-III-R and social functioning criteria. Case-notes were reviewed to cull data regarding social life, criminal record and service use. RESULTS: Inmates were more likely to suffer from delusional/NOS psychotic disorders (72%) or major depression (70%), and psychiatric in-patients from schizophrenic or bipolar disorder (62% and 71%, respectively). Comorbidity was more prevalent among inmates than among in-patients, while in-patients presented less social autonomy than did inmates. CONCLUSIONS: The clinical specificity of prison inmates with severe mental disorders clearly differentiates them from psychiatric in-patients, and warrants recognition of their special needs for assessment and integrated treatment approaches.

Adaptation, Psychological↗

PubMed1997

Novel mutations and DNA-based screening in non-Jewish carriers of Tay-Sachs disease.

We have evaluated the feasibility of using PCR-based mutation screening for non-Jewish enzyme-defined carriers identified through Tay-Sachs disease-prevention programs. Although Tay-Sachs mutations are rare in the general population, non-Jewish individuals may be screened as spouses of Jewish carriers or as relatives of probands. In order to define a panel of alleles that might account for the majority of mutations in non-Jewish carriers, we investigated 26 independent alleles from 20 obligate carriers and 3 affected individuals. Eighteen alleles were represented by 12 previously identified mutations, 7 that were newly identified, and 1 that remains unidentified. We then investigated 46 enzyme-defined carrier alleles: 19 were pseudodeficiency alleles, and five mutations accounted for 15 other alleles. An eighth new mutation was detected among enzyme-defined carriers. Eleven alleles remain unidentified, despite the testing for 23 alleles. Some may represent false positives for the enzyme test. Our results indicate that predominant mutations, other than the two pseudodeficiency alleles (739C-->T and 745C-->T) and one disease allele (IVS9+1G-->A), do not occur in the general population. This suggests that it is not possible to define a collection of mutations that could identify an overwhelming majority of the alleles in non-Jews who may require Tay-Sachs carrier screening. We conclude that determination of carrier status by DNA analysis alone is inefficient because of the large proportion of rare alleles. Notwithstanding the possibility of false positives inherent to enzyme screening, this method remains an essential component of carrier screening in non-Jews. DNA screening can be best used as an adjunct to enzyme testing to exclude known HEXA pseudodeficiency alleles, the IVS9+1G-->A disease allele, and other mutations relevant to the subject's genetic heritage.

California↗

PubMed1996

[Suicide prevention by preventing mental disorders: how far did we get in Quebec?].

The relationship between mental illness and suicide no longer has to be demonstrated. In Quebec however, those intervening in the prevention of suicide, without denying this link, appear not to have integrated this information in their practice. As in North America and Europe, very few prevention centres have evaluated the efficiency and impact of their intervention. Finally, the few programs promoting mental health or preventing mental illness elaborated in Quebec seldom aim at preventing suicide. In these conditions how can we expect reducing the suicide rate?

Humans↗

PubMed1995

Interallelic complementation of beta-subunit defects in fibroblasts of patients with propionyl-CoA carboxylase deficiency microinjected with mutant cDNA constructs.

Propionic acidemia results from deficiency of propionyl-CoA carboxylase (PCC) activity. PCC is a biotin-dependent, mitochondrial enzyme composed of alpha- and beta-subunits (structure, alpha 4 beta 4), with the alpha-subunit containing the biotin ligand. About two-thirds of fibroblast lines from patients with mutations in the PCCB (beta-subunit) gene show interallelic complementation in cell fusion experiments (the pccB and pccC subgroups of the pccBC major group defining beta-subunit mutations, where pccB x pccC fusions show complementation). We previously identified the mutations in several pccB or pccC cell lines and suggested that point mutations or small, in-frame insertions or deletions were likely responsible for the complementation obtained between beta-subunit defects. To test this hypothesis, we have introduced five different mutations (three pccB and two pccC) that fit these criteria into a PCC beta-subunit cDNA plasmid expressed from a cytomegalovirus promoter. The cDNA plasmids were microinjected into mutant fibroblasts and the cells were assayed by radioautographic detection of 14C-propionate incorporation into cellular macromolecules. Four different mutations (Pro228Leu or dupKICK140 from pccB or delta IIe408 or Arg410Trp from pccC) complemented cells from complementation subgroups in a pattern congruent with the results obtained in cell fusion experiments. The fifth mutation, Arg536Asn, which was found both in a complementing pccB and a non-complementing pccBC cell line, failed to complement any of the mutant cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Metabolism, Inborn Errors↗

PubMed1994

Correction of the metabolic defect in propionic acidemia fibroblasts by microinjection of a full-length cDNA or RNA transcript encoding the propionyl-CoA carboxylase beta subunit.

Propionyl-CoA carboxylase (PCC) is a mitochondrial, biotin-dependent enzyme, composed of an equal number of alpha and beta subunits, that functions in the catabolism of branched-chain amino acids and other metabolites. Mutations of the PCCA (alpha subunit) or PCCB (beta subunit) gene cause the inherited metabolic disease, propionic acidemia. We report the cloning of a full-length cDNA encoding the beta subunit of human PCC. The open reading frame encodes a pre-beta polypeptide of 539 amino acids (58,205 Da). The cDNA was introduced into the expression vector, pRc/CMV, and microinjected into the nucleus or, as ribotranscripts, into the cytoplasm of fibroblast lines from patients with defects of the beta subunit. The restoration of function was monitored by autoradiography of PCC-dependent [14C]-propionate incorporation into cellular protein. These results confirm the completeness of the clone and demonstrate the capacity for beta subunits derived from the microinjected cDNA or RNA to be transported into mitochondria and assembled with endogenously derived alpha subunits to form functional PCC.

Amino Acid Sequence↗

PubMed1994

Suicide and mental disorders: a case-control study of young men.

OBJECTIVE: By means of the psychological autopsy method and a case-control design, the authors examined the association of specific mental disorders and comorbidity with suicide among young men. METHOD: Seventy-five men aged 18-35 years whose deaths were adjudicated as completed suicides by coroners of greater Montreal and Quebec City were matched to 75 living young men for age, neighborhood, marital status, and occupation. For each subject in both groups a key respondent best acquainted with the subject was interviewed by clinicians using standardized schedules. Information from the coroner and medical records was also collected. Two experienced psychiatrists, blind to outcome, established best-estimate DSM-III-R diagnoses. RESULTS: Six-month prevalence rates for all axis I diagnoses for the suicide and comparison groups were 88.0% and 37.3%, respectively; major depression was present in 38.7% and 5.3%, alcohol dependence in 24.0% and 5.3%, psychoactive substance dependence in 22.7% and 2.7%. Borderline personality disorder was identified in 28.0% and 4.0%, respectively. Of the suicide subjects, 28.0% had at least two of the following disorders: major depression, borderline personality disorder, and alcohol or drug dependence; the rate was 0.0% among the comparison subjects. CONCLUSIONS: In young men, completed suicide is linked to specific mental disorders, namely, major depression, borderline personality disorder, and substance abuse. Comorbidity involving any of these disorders is frequently associated with completed suicide.

Adolescent↗

PubMed1994

[Suicide among young male adults in Quebec: psychopathology and utilization of medical services].

Seventy five young male adults between the age of 18 and 35 who had committed suicide were compared with 75 male adults still alive matched for age, residence, marital and employment status. For each group a principal respondent was interviewed in order to reconstitute the psychological profile of each individual, as well as their utilisation of health services. This was completed by the study of the coroner's reports and the medical records when available. At six months the prevalence for all axis I diagnosis was 88.8% for the suicide group and 37.3% for the control group. Among the subjects who had committed suicide 38.7% were afflicted by major depression, 24% by alcohol dependency and 28.7% were dependent on drugs. Borderline personalities were present in 28% of the suicide group compared to 5% in the control group. Forty five percent (45%) of the subjects who had killed themselves had consulted a mental health professional in the year preceding the suicide compared to 5% in the control group. However, 78.5% of the suicide group had consulted during the same period a health professional compared to 73.3% of the controls.

Adolescent↗

PubMed1994

Mutations participating in interallelic complementation in propionic acidemia.

Deficiency of propionyl-CoA carboxylase (PCC; alpha 4 beta 4) results in the rare, autosomal recessive disease propionic acidemia. Cell fusion experiments have revealed two complementation groups, pccA and pccB, corresponding to defects of the PCCA (alpha-subunit) and PCCB (beta-subunit) genes, respectively. The pccBCC group includes subgroups, pccB and pccC, which are thought to reflect interallelic complementation between certain mutations of the PCCB gene. In this study, we have identified the mutations in two pccB, one pccC, and two pccBC cell lines and have deduced those alleles participating in interallelic complementation. One pccB line was a compound heterozygote of Pro228Leu and Asn536Asp. The latter mutation was also detected in a noncomplementing pccBC line. This leaves Pro228Leu responsible for complementation in the pccB cells. The second pccB line contained an insertional duplication, dupKICK140-143, and a splice mutation IVS + 1 G-->T, located after Lys466. We suggest that the dupKICK mutation is the complementing allele, since the second allele is incompatible with normal splicing. The pccC line studied was homozygous for Arg410Trp, which is necessarily the complementing allele in that line. For a second pccC line, we previously had proposed that delta Ile408 was the complementing allele. We now show that its second allele, "Ins.Del," a 14-bp deletion replaced by a 12-bp insertion beginning at codon 407, fails to complement in homozygous form. We conclude that the interallelic complementation results from mutations in domains that can interact between beta-subunits in the PCC heteromer to restore enzymatic function. On the basis of sequence homology with the Propionibacterium shermanii transcarboxylase 12S subunit, we suggest that the pccC domain, defined by Ile408 and Arg410, may involve the propionyl-CoA binding site.

Alleles↗

PubMed1990

Comparative study of hemolytic substances produced by coagulase-negative Staphylococcus strains.

Hemolytic substances H7, H62, and E56, produced by Staphylococcus haemolyticus 7 and 62 and S. epidermidis 56, respectively, were purified. H7 and H62 are probably similar on the basis of their isoelectric focusing profiles in 8 M urea and complete immunological identity as revealed by immunodiffusion with rabbit anti-H7 and anti-E56 sera. For E56, we observed seven bands instead of three in isoelectric focusing and only partial immunological identity with H7 and H62. However, H7 and E56 were similar with regard to the following characteristics: hemolytic spectra against different erythrocytes, kinetics of erythrocyte lysis, heat stability, and inhibition by phosphatidylcholine. E56 was not active at a temperature lower than or equal to 25 degrees C, and its activity increased more rapidly with increased temperature compared with H7. For both substances, the complexes obtained by molecular filtration on Ultrogel AcA54 and the purified peptides by reverse-phase high-pressure liquid chromatography showed some hemolytic activity. These results suggest that a particular association or the presence of a given peptide could enhance the activity.

Chromatography, High Pressure Liquid↗