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Biomedical subjects

M Crespi

Publications and source records attributed to M Crespi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Prevalence survey of precancerous lesions of the oesophagus in a high-risk population for oesophageal cancer in France.

The prevalence of precancerous lesions of the oesophagus and their association with alcohol drinking, tobacco smoking and some dietary factors were examined in an endoscopic survey carried out in Lower Normandy, France, a high-risk area for oesophageal cancer. The study included 134 male volunteers of 35-64 years of age. In 124 of the volunteers oesophageal biopsies were evaluable. At histology, the prevalence of chronic oesophagitis, epithelial atrophy and dysplasia was 63%, 1.6% and 4.8%, respectively. The prevalence of these precancerous lesions was significantly associated with cigarette smoking and frequent consumption of butter.

Adult↗
PubMed1992

Pre-cancerous lesions of the oesophagus in Argentina: prevalence and association with tobacco and alcohol.

The prevalence of pre-cancerous lesions of the oesophagus and their association with alcohol and tobacco were examined in an endoscopic survey carried out in La Plata, Argentina. The study included 406 subjects over 15 years of age attending several gastroenterology clinics because of various gastrointestinal symptoms. Among males, the prevalence rates of chronic oesophagitis, epithelial atrophy and dysplasia were 42%, 3.8% and 2.4% respectively, and in females these prevalences were 36%, 2.5% and 0.0%. The presence of these pre-cancerous lesions was significantly associated with alcohol drinking and tobacco smoking.

Adolescent↗
PubMed1992

Isolation and characterization of genes encoding chaperonin 60 beta from Arabidopsis thaliana.

Chaperonins (Cpn) are implicated in the folding and assembly of multimeric proteins in plastids and mitochondria of eukaryotes and in prokaryotes. Plastid Cpn is composed of two different polypeptides termed Cpn60 alpha and Cpn60 beta. We have isolated cDNA and genomic clones encoding Cpn60 beta from Arabidopsis thaliana. The steady-state level of the cpn60 beta mRNAs is higher in etiolated leaves and sucrose-treated plants as compared to control leaves. The A. thaliana cpn60 beta gene family consists of at least three different coding units. It was confirmed that Cpn beta-encoding genes have a high level of conservation among plants.

Amino Acid Sequence↗
PubMed1992

Fasciation induction by the phytopathogen Rhodococcus fascians depends upon a linear plasmid encoding a cytokinin synthase gene.

Rhodococcus fascians is a nocardiform bacteria that induces leafy galls (fasciation) on dicotyledonous and several monocotyledonous plants. The wild-type strain D188 contained a conjugative, 200 kb linear extrachromosomal element, pFiD188. Linear plasmid-cured strains were avirulent and reintroduction of this linear element restored virulence. Pulsed field electrophoresis indicated that the chromosome might also be a linear molecule of 4 megabases. Three loci involved in phytopathogenicity have been identified by insertion mutagenesis of this Fi plasmid. Inactivation of the fas locus resulted in avirulent strains, whereas insertions in the two other loci affected the degree of virulence, yielding attenuated (att) and hypervirulent (hyp) bacteria. One of the genes within the fas locus encoded an isopentenyltranferase (IPT) with low homology to analogous proteins from Gram-negative phytopathogenic bacteria. IPT activity was detected after expression of this protein in Escherichia coli cells. In R.fascians, ipt expression could only be detected in bacteria induced with extracts from fasciated tissue. R.fascians strains without the linear plasmid but containing this fas locus alone could not provoke any phenotype on plants, indicating additional genes from the linear plasmid were also essential for virulence. These studies, the first genetic analysis of the interaction of a Gram-positive bacterium with plants, suggest that a novel mechanism for plant tumour induction has evolved in R.fascians independently from the other branches of the eubacteria.

Alkyl and Aryl Transferases↗
PubMed1992

Determination of textile dyes in organs of Oncorhynchus mykiss W. after in vitro exposure.

The quantitative determination in organs of Oncorhynchus mykiss W. of a premetallized dye (C.I. Acid Violet 66) and the azoic base (C.I. Acid Red 217), used in wool dyeing, is studied in this paper. UV-VIS Spectrophotometry was used for the chromatic quantification and atomic absorption spectrophotometry for the detection of the metal. The method described here is as satisfactory for the detection of some commercial dyes as the methods developed by ETAD (Ecological and Toxicological Association of the Dyestuffs Manufacturing Industry).

Animals↗
PubMed1992

The plasmid-encoded chloramphenicol-resistance protein of Rhodococcus fascians is homologous to the transmembrane tetracycline efflux proteins.

The nucleotide sequence of the chloramphenicol-resistance gene (cmr) of Rhodococcus fascians NCPPB 1675 (located on the conjugative plasmid pRF2) allowed the identification of two possible open reading frames (ORFs), of which ORF1 was consistent with the mutational analysis. Biochemical analysis of cmr revealed that it does not encode an antibiotic-modifying enzyme. The amino acid sequence of ORF1 predicted a hydrophobic protein, with 12 putative membrane-spanning domains, homologous to proteins involved in the efflux of tetracycline across the plasma membrane. Expression of the cmr gene was induced by addition of chloramphenicol to the growth media. The promoter of this gene was restricted to 50 bp upstream from a 200 bp 5'-untranslated mRNA region, the latter containing two inverted repeats. At the amino acid level, the cmr gene is 52% identical to a previously identified chloramphenicol-resistance determinant in Streptomyces lividans, indicating a wider dispersion of this type of cmr gene among the actinomycetes.

Amino Acid Sequence↗
PubMed1991

Illegitimate integration of non-replicative vectors in the genome of Rhodococcus fascians upon electrotransformation as an insertional mutagenesis system.

Electrotransformation of Rhodococcus fascians by non-replicating plasmids containing a suitable resistance marker resulted in stable transformants by integration of these constructs at various sites in the genome, thereby generating different mutations. Tagged genes could be isolated in Escherichia coli owing to the presence of a CoIE1 replicon and an ampicillin resistance gene in the inserted sequences. Southern analysis and nucleotide sequencing revealed that recombination can occur at defined locations in the plasmid, while no site preference for target sequences could be detected. Low homology between the recombining sequences indicates illegitimate recombination. The specificity of the plasmid sites could be explained by assuming a linear recombination intermediate, generated by cleavage of the transformed plasmid.

Base Sequence↗
PubMed1991

Epidemiological study of precursor lesions of oesophageal cancer among young persons in Huixian, China.

A total of 538 subjects (354 males, 184 females) were investigated in a high-risk area for oesophageal cancer in China to provide large-scale data on the prevalence of chronic oesophagitis among persons below 25 years of age. The survey included an oesophagoscopy with guided biopsies and cytology, a physical examination, an interview and collection of a 10-ml blood sample and overnight urine. Histologically confirmed oesophagitis was found in 43.5% of male and 35.6% of female subjects. Mild and moderate oesophagitis was associated positively with consumption of burning hot beverages, family history of oesophageal cancer, frequent consumption of cottonseed oil, cigarette smoking, a clinical diagnosis of oral leukoplakia and seborrhoeic dermatitis; negative associations were seen with frequent consumption of fresh fruit, meat and eggs. A significantly higher level of urinary nitrate was found in the diseased group, but no difference was seen with regard to any of the N-nitrosamino acids measured.

Adolescent↗
PubMed1990

An epidemiological study of precursor lesions of esophageal cancer among young persons in a high-risk population in Huixian, China.

The occurrence of chronic esophagitis, considered a precursor condition for esophageal cancer, among persons 15 to 26 yr of age and risk factors for the disease were investigated in Huixian, Henan Province, a high-risk area for esophageal cancer in the People's Republic of China. The 538 study subjects underwent an esophagoscopy with guided biopsies and cytology, a physical examination, an interview with a questionnaire including known and suspected risk factors for esophageal lesions, and collection of a 10-ml blood sample and overnight urine. One-third of the subjects was selected from households with a case of esophageal cancer in the past 6 yr and two-thirds came from control households. Histologically confirmed very mild, mild, and moderate esophagitis was observed in 31.6%, 10.7%, and 1.1% of 354 male and 30.4%, 4.3%, and 1.1% of 184 female subjects, respectively. In the multivariate case-control analysis of mile and moderate esophagitis compared with very mild esophagitis and normal subjects, the prevalence of mild and moderate disease was found to be positively associated with the consumption of burning hot beverages [odds ratio (OR) = 4.7], the prevalence of esophagitis among siblings (OR = 4.4), and family history of esophageal cancer (OR = 1.8) and negatively associated with the frequent consumption of fresh fruits (OR = 0.3) and wheat flour products (OR = 0.4). Weaker associations were seen for cigarette smoking and the use of cottonseed oil as the main cooking oil. Univariate associations seen with a clinical diagnosis of oral leukoplakia (OR = 2.7) and seborrheic dermatitis (OR = 3.7) are probably due to common risk factors such as smoking and nutritional deficiency. The present findings suggest that exposures early in life to environmental risk factors and nutritional deficiency may be responsible for inflammation and a weakened esophageal epithelium, resulting in a condition possibly more favorable for the development of esophageal cancer.

Adolescent↗
PubMed1989

Precursor lesions of oesophageal cancer in young people in a high-risk population in China.

Young people (15-26 years) were selected from households in a population in China at high risk of oesophageal cancer on the basis of whether a case of oesophageal cancer had (166 participants) or had not (372 participants) occurred in a first-degree relative. In an endoscopic survey 43.5% of the male subjects and 35.9% of the female subjects showed histological signs of chronic oesophagitis. The presence of these precursor lesions was significantly associated in a multivariate logistic model with consumption of burning hot beverages, a family history of oesophageal cancer (including second-degree relatives), infrequent consumption of fresh fruit, and infrequent consumption of dietary staples other than maize.

Adolescent↗
PubMed1989

The effect of interferon on cells persistently infected with HIV.

In this study the effect of interferon (IFN) on uninfected cells (H9-) and cells infected (H9+) with HIV-1 was investigated. In both H9- and H9+, IFN was unable to inhibit Sindbis virus replication. HIV-1 replication was inhibited by a maximum of 22% at 1000 U/ml of IFN. In both H9- and H9+ cells IFN exhibited a limited antiproliferative effect. There was activation of the 2'-5' oligo-A-synthetase (E enzyme) and the protein kinase enzyme systems, but low activation of the ribonuclease F was seen in both H9- and H9+ cells. From these results it can be concluded that IFN produces a limited antiviral and antiproliferative effect in both H9- and H9+ cells, and a defective ribonuclease F pathway might be responsible for this limited activity.

Cell Line↗
PubMed1988

Interferon status after measles virus infection.

Peripheral blood leucocytes from patients who had recently had measles infection were examined for their ability to produce alpha- or gamma-interferon, their antiviral state and the level of E enzyme. These results were compared with peripheral blood leucocytes from healthy control subjects. The results show that while peripheral blood leucocytes from control patients produced alpha- and gamma-interferon, those from the measles patients produced only alpha-interferon. The peripheral blood leucocytes from all the measles patients were in an antiviral state whereas those from only 20% of the controls were in this state. Since gamma-interferon is mainly produced by T lymphocytes, the lack of gamma-interferon production by peripheral blood leucocytes from patients with measles correlates with previously reported depressed T-cell function in patients after measles infection.

Adolescent↗
PubMed1988

Blood, retinol and zinc riboflavin status in relation to precancerous lesions of the esophagus: findings from a vitamin intervention trial in the People's Republic of China.

Data from a double-blind intervention trial in China are reanalyzed to explore auxiliary information. The trial had shown that in a high-risk area for esophageal cancer the dietary supplementation of apparently healthy individuals with a combination of retinol, riboflavin, and zinc did not lead to a different prevalence of precancerous lesions of the esophagus among those receiving the active treatment compared to a placebo group. However, improvement of blood retinol and zinc levels were also observed in the placebo group. The logistic regression analysis presented in this paper illustrates that those individuals who showed large increases in retinol, riboflavin, and zinc blood levels were more likely to have a histologically normal esophagus at the end of the trial. This effect is clearer for retinol than for riboflavin and zinc and it is independent of whether the change was caused by the active treatment or occurred otherwise.

Adult↗
PubMed1988

Effect of interferon on Vero cells persistently infected with Sendai virus compared to Vero cells persistently infected with SSPE virus.

Persistent infections with Sendai and SSPE virus were established in Vero cells. Sequential passages of these cells were monitored by immunofluorescence and for their sensitivity to the antiviral and antiproliferative effects of interferon (IFN). The cells rapidly developed resistance to the antiviral effect of IFN as judged by the inability of IFN to inhibit the replication of exogenous Sindbis virus. This decrease was accompanied by a reduction in the induction of the 2'-5' oligo A synthetase. Both cell lines were resistant to the antiproliferative effect of IFN. A decrease or absence of IFN receptors on the surface of the cells was not found to be the cause of their resistance to IFN.

2',5'-Oligoadenylate Synthetase↗