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Biomedical subjects

M Simon

Publications and source records attributed to M Simon.

At least 307 records · Page 17Linked to original sources
PubMed1993

Psychiatric manifestations of olivo-ponto-cerebellar atrophy and treatment with clozapine.

Patients with multiple system atrophy, a neurodegenerative disease entity, have a high incidence of associated mental disturbances such as a mood disorder with or without psychotic features. Treatment of the psychiatric symptoms, without compromising neurological status, is often complicated and unsuccessful. This article describes a patient with olivo-ponto-cerebellar atrophy and treatment-resistant psychotic depression whose psychiatric symptoms were successfully treated with clozapine without aggravating the neurological disabilities.

Clozapine↗
PubMed1993

[Necrotizing fasciitis, caused by Neisseria meningitidis, simultaneously involving an arm and a leg].

INTRODUCTION: Necrotizing fasciitis is usually due to Streptococcus species but can be caused by a variety of organisms, among which Neisseria species are distinctly rare, as only four cases have been reported in the literature. CASE REPORT: We report the first case of Neisseria meningitidis necrotizing fasciitis in a non-immunocompromised man, with a possibly predisposing effect of non-steroidal anti-inflammatory drugs. Neisseria meningitidis group C was isolated from subcutaneous and bullae aspirates. The involvement of two distant sites strongly suggests hematogenous dissemination of the microorganism. Four previous cases of fasciitis caused by Neisseria species are reviewed. CONCLUSION: Although Streptococcus group A is the main cause of apparently primary necrotizing fasciitis, Neisseria meningitidis must be considered a possible etiologic agent of this severe soft tissue infection.

Arm↗
PubMed1993

[Frequent occurrence of BoLA w16 in cows susceptible to mastitis].

The association between BoLA class I antigens and mastitis was studied in Boheman Pied breed and its crosses. The mastitis status was followed during two years according to three diagnostic criteria: California Mastitis Test, bacteriological findings and the altered taste of milk. The antigen w16 was found to be significantly associated with susceptibility to mastitis in all diagnostic tests. On the other hand there were some indications that the wll animals were rather resistant to mastitis.

Animals↗
PubMed1993

Predictors of dental students' belief in the right to refuse treatment to HIV-positive patients.

We examined predictors of dental student's belief that they should be allowed to refuse treatment to HIV-infected persons. We surveyed 181 first; second-, and fourth-year dental students at a large urban university using a 44-item, self-administered anonymous questionnaire and a measure of dispositional optimism. Several composite measures were created and their relationship to belief in the right to refuse treatment was assessed. Regression techniques were used to describe the relationship between the dependent and independent variables. Results indicated that non-professional attitudes, low optimism scores, low levels of comfort with homosexuality, and gender were the best predictors of belief in the right to refuse treatment to HIV-infected patients. Neither knowledge of HIV, year in dental school, or fear of contagion reliably predicted belief in the right to refuse treatment.

Adult↗
PubMed1993

Symptomatic displacement of the lesser trochanter following trochanteric fracture fixation.

Unstable intertrochanteric hip fractures are characterized by comminution of the posteromedial cortex, resulting in a fragment of variable size containing the lesser trochanter. Controversy exists as to whether it is necessary to perform reduction and fixation of this fragment. This case lends further support to the practice of fixating the lesser trochanteric fragment in unstable intertrochanteric fractures.

Aged↗
PubMed1993

Approaches for providing target values to improve usefulness of external quality assessment scheme. The Spanish experience.

The aim of this communication is to highlight the specific aspects of external quality assessment schemes that need to be discussed in a European context: target values, transferability of results and accredit of laboratories. The Spanish situation is presented here. The most reliable way to provide target values is to analyse the control samples by reference methods. However, it is not possible for the majority of national schemes and other approaches are presently used: the verification of consensus means is a practicable solution adopted in Spain. An initial network involving selected routine laboratories has been developed, to attain transferability of results. The traceability of routine calibrators from certified reference materials should be demonstrated. To accredit laboratories for licensing is a complex activity that should consider many aspects, results from the national quality assessment scheme bring one. A scoring system is being used in Spain for guidance, and the complete guidelines are under preparation.

Accreditation↗
PubMed1992

Substrate analogue induced changes of the CO-stretching mode in the cytochrome P450cam-carbon monoxide complex.

The CO-stretching mode of the carbon monoxide ligand in reduced cytochrome P450cam, in the absence or presence of camphor and in the presence of nine different camphor analogues, was measured at room temperature using Fourier transform infrared spectroscopy. Substrate-free cytochrome P450cam--CO reveals a broad, slightly structured band resulting from an overlap of several stretching mode signals. The multitude of the signals indicates that cytochrome P450 exists in a dynamic equilibrium of several conformational substates. Binding of camphor or camphor analogues strongly influences this equilibrium. For substrate analogues which are not able to form a hydrogen bond to the hydroxyl group of tyrosine 96, the CO-stretching band is rather broad and asymmetric. In contrast, substrate analogues with one quinone group which form a hydrogen bond to the Tyr96 OH induce a shift and a sharpening of the CO-stretching mode band. For substrate analogues with two hetero groups, the infrared spectrum is slightly asymmetric or a minor band appears. Sterical hindrance, substrate mobility, and protein flexibility finally determine the position and width of the CO-stretching mode signals.

Camphor↗
PubMed1992

[Ocular manifestations in porphyria cutanea tarda].

Ninety two patients suffering from porphyria cutanea tarda were examined ophthalmologically in a paired case-control study. The incidence of pinguecula and that of pterygium were 8 times and 2 times higher, respectively, in PCT patients that in the control group. The photodamage of the conjunctiva is presumed to be a result of the photoactivity of uroporphyrin in the tissues.

Conjunctiva↗
PubMed1992

Supercoiled DNA wraps around the bacteriophage phi 29 head-tail connector.

Supercoiled pBR322 DNA wraps around the outside of the isolated Bacillus subtilis bacteriophage phi 29 head-tail connector, the crux of the DNA packaging machine of the viral precursor capsid or prohead. The contour length of the supercoiled DNA, determined by EM, decreased by approximately 180 base pairs for each connector bound. Mass and radial density determinations by scanning transmission EM showed that the increased mass of the connector-DNA complex relative to the connector alone was equivalent to approximately 170 base pairs of DNA and was located around the outside of the connector. Topoisomerase I treatment of the complexes followed by deproteinization suggested that supercoils were restrained by the connectors. Connectors bound linear and open-circular plasmid DNAs inefficiently but were not wrapped by these DNAs. The wrapping of supercoiled DNA around the isolated phi 29 connector is hypothesized to reflect the initiation phase of the normal process of DNA packaging. Packaging substrates would be supercoiled, wrapped by the connector, linearized, and translocated by rotation of the connector relative to the viral capsid with the aid of ATP hydrolysis.

Bacillus Phages↗
PubMed1992

Cloning and stable maintenance of 300-kilobase-pair fragments of human DNA in Escherichia coli using an F-factor-based vector.

A bacterial cloning system for mapping and analysis of complex genomes has been developed. The BAC system (for bacterial artificial chromosome) is based on Escherichia coli and its single-copy plasmid F factor. It is capable of maintaining human genomic DNA fragments of greater than 300 kilobase pairs. Individual clones of human DNA appear to be maintained with a high degree of structural stability in the host, even after 100 generations of serial growth. Because of high cloning efficiency, easy manipulation of the cloned DNA, and stable maintenance of inserted DNA, the BAC system may facilitate construction of DNA libraries of complex genomes with fuller representation and subsequent rapid analysis of complex genomic structure.

Cloning, Molecular↗
PubMed1992

Identification of murine homologues of the Drosophila son of sevenless gene: potential activators of ras.

Several findings suggest that signals from tyrosine kinases are transduced, at least in part, through ras proteins. These findings include (i) blockage of the transforming activity of constitutively active tyrosine kinases by inhibiting ras function and (ii) genetic screens in Caenorhabditis elegans and in Drosophila that identified ras genes as downstream effectors of tyrosine kinases. The recently isolated Drosophila gene Son of sevenless (Sos) is postulated to act as a positive regulatory link between tyrosine kinase and ras proteins by catalyzing exchange of GDP for GTP on ras protein. Such exchange proteins have been reported in extracts of mammalian cells but have not been previously characterized at a molecular level. As Sos appears to function in this role in Drosophila, we sought to isolate a vertebrate counterpart(s). We have characterized two widely expressed murine genes with a high degree of homology to Sos. Hybridization with human DNA and RNA indicates a high degree of conservation of these genes in other vertebrates.

Amino Acid Sequence↗
PubMed1992

Immune-associated surface markers of human keratinocytes.

The results of a number of investigations have proved that human keratinocytes (HKs) possess the ability to synthesize and express cell surface moieties characteristic of effector and/or accessory cells of the immune system. The present paper summarizes the known immune cell surface features of HKs, reflecting their stage of activation and differentiation. The surface and functional characteristics of HKs suggest their monocyte/macrophage behavior, which fits in well with the presumed active involvement of HKs in the skin immune system.

Antigens, CD↗
PubMed1992

The continuing dilemma of lobular carcinoma in situ.

We reviewed the courses of 250 consecutive women with lobular carcinoma in situ of the breast entered into the Surveillance, Epidemiology, and End Results program of the Michigan Cancer Foundation, Detroit, Mich, between 1973 and 1986. No patient had known invasive cancer at the time of initial entry. The average follow-up was 93.1 months; 212 patients had mastectomy for the initial lesion and 65 patients had less than mastectomy, of whom one developed a new lesion in the ipsilateral breast. Thirty-seven patients (14.8%) were later found to have lesions in the contralateral breast, 25 within the first year. Thirteen of the 38 lesions (5.2% of the total series) were invasive, and 11 were primarily ductal. Seventeen patients died, two of breast cancer, two of unknown causes, and 13 of non-breast-related causes. The maximum mortality from breast cancer is 1.6% to this point. The frequency of mastectomy fell from 78.1% in the years 1973 through 1983 to 52% in 1984 through 1986, reflecting a change in surgical philosophy. Although no guarantees can be given to any individual patient, the great majority of patients with LCIS unassociated with a proved invasive cancer can be safely treated with less than mastectomy.

Breast Neoplasms↗
PubMed1992

Control of peroxisome proliferation in Saccharomyces cerevisiae by ADR1, SNF1 (CAT1, CCR1) and SNF4 (CAT3).

The Saccharomyces cerevisiae ADR1 gene has recently been demonstrated to control transcription of several genes encoding peroxisomal proteins or proteins necessary for peroxisome formation. Therefore, the effect of two other genes (SNF1 (CAT1, CCR1) and SNF4 (CAT3)) known to control derepression of glucose-repressible genes was studied. Levels of transcripts of genes encoding catalase A, fatty acid beta-oxidation enzymes and of the PAS1 gene are reduced in snf1 and snf4 mutants on ethanol as well as on oleic acid medium. By immunogold labelling with an antibody directed against peroxisomal thiolase, clusters of peroxisomes were detected in wild-type cells, whereas smaller single peroxisomes were observed in adr1 mutant cells. Results of immunofluorescence experiments are consistent with these observations. No peroxisomes were detected in snf1 and snf4 mutants by immunogold labelling as well as by immunofluorescence.

Acetyl-CoA C-Acetyltransferase↗