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Biomedical subjects

M Crespi

Publications and source records attributed to M Crespi.

At least 37 records · Page 2Linked to original sources
PubMed1999

The GASTER project: building a computer network in digestive endoscopy: the experience of the European Society for Gastrointestinal Endoscopy. Gastrointestinal Endoscopy Application for Standards in Telecommunication, Education and Research.

Digestive endoscopy is currently the main diagnostic procedure for investigation of the digestive tract whenever a digestive disease is suspected. From 1970 to 1985, digestive endoscopy was performed with endoscopes equipped with fiberoptic bundles, whereas the last decade was marked by the development of electronic endoscopes, characterized by the presence of a CCD (charge coupled device) at the tip of the endoscope. Thus the physician looks at a TV screen to control the procedure and examine in detail the gut wall. Endoscopes examine the foregut until the duodenum and the hindgut, up to the three last intestinal loops. When the endoscopic workstation comprises a computer, it is possible to acquire electronic images during the endoscopy and use these images as support of the information about the results of the procedure. These numeric images can then be stored in databases containing text attached to them. Starting with these images, one may expect many developments in the near future that will change the management of the patient with digestive diseases. Physicians will become able to exchange images and text related to one patient or one procedure, although they are equipped with different workstations. Therefore, it is obvious that the information exchanged must be written in a standard format that makes it understandable by all systems. The European Society of Gastrointestinal Endoscopy is a scientific society that groups most of the gastroenterologists in Europe. This society has initiated a research program to develop standards for the exchange of images and text. The Gastrointestinal Endoscopy Applications for Standards in Telecommunication, Education, and Research (GASTER) project intends to implement a multimedia database of endoscopic images based on a standard format of images and a standard terminology for descriptive terms. These standards must be validated by use in different endoscopy units. The database will collect images from these centers that will be linked to the coordinating center through a network based on an integrated services digital network (fast electronic connection). This database will then be used for the development of computer applications. The output of the GASTER project will bring advances at three levels: (1) The physicians will be able to exchange images about the procedures their patients have undergone and will thus obtain more complete information, improving quality of care. They will also benefit from help-to-decision applications based on validated reference images from the database. (2) At the patient level, the quality of care will be improved through a better dissemination of information between the physicians in charge of the patient, thus there is better follow-up of the patient and a decrease in redundant examinations. (3) At the level of national health care systems, the benefit will be a decrease in cost of care due to a better follow-up of the patients, a decrease in redundant examinations, and a faster decision made to treat the patient. The possibility of consulting a database of a scientifically validated images used as reference material will also improve quality control in digestive endoscopy.

Computer Communication Networks↗
PubMed1999

Alteration of enod40 expression modifies medicago truncatula root nodule development induced by sinorhizobium meliloti

Molecular mechanisms involved in the control of root nodule organogenesis in the plant host are poorly understood. One of the nodulin genes associated with the earliest phases of this developmental program is enod40. We show here that transgenic Medicago truncatula plants overexpressing enod40 exhibit accelerated nodulation induced by Sinorhizobium meliloti. This resulted from increased initiation of primordia, which was accompanied by a proliferation response of the region close to the root tip and enhanced root length. The root cortex of the enod40-transformed plants showed increased sensitivity to nodulation signals. T(1) and T(2) descendants of two transgenic lines with reduced amounts of enod40 transcripts (probably from cosuppression) formed only a few and modified nodulelike structures. Our results suggest that induction of enod40 is a limiting step in primordium formation, and its function is required for appropriate nodule development.

Journal Article↗
PubMed1998

The minimal standard terminology for digestive endoscopy: introduction to structured reporting.

The wider use of computers for the management of endoscopic data and the use of electronic endoscopes for the production of high quality endoscopic images has made the standardization of terminology and images formats necessary in digestive endoscopy reports. The European Society for Gastrointestinal Endoscopy and the American Society for Gastrointestinal Endoscopy have combined their efforts to propose a Minimal Standard Terminology for Computerized Databases in Endoscopy. This terminology is based on the following principles: no term describing findings less frequent than 1%, of the daily practice, and no term based on subjective impressions. The Minimal Standard Terminology has been developed according to the natural process of constructing an endoscopic report in natural language and deals with the following: reasons for performing the examination, endoscopic findings, endoscopic diagnosis, additional therapeutic and diagnosis procedures (biopsies, etc.). It is subdivided according to the main organs examined with an endoscopy. Until now, the Minimal Standard Terminology was tested in many centers and was shown to accurately cover 95% of routine examinations for the upper gastrointestinal tract, colonoscopy and cholangio-pancreatography. It is currently being tested in an a prospective way in several centers in Europe (with a grant from the European Commission DGXIII-C4) and in the USA (with grant from the AHDHF).

Endoscopy, Digestive System↗
PubMed1998

Identification of novel putative regulatory genes induced during alfalfa nodule development with a cold-plaque screening procedure.

Until now very few plant genes with possible regulatory functions during nodule development have been isolated. We have used a modified cold-plaque screening method to identify new transcripts expressed at low levels that are induced during nodulation. Several clones were isolated and characterized by their mRNA expression patterns during nodule development and in spontaneous nodules. Sequence homology with known genes of other organisms indicated that transcripts corresponded to (i) "basic" genes probably required during the growth of the nodule organ (e.g., structural proteins), (ii) genes related to the metabolic adaptations taking place during nodule morphogenesis and function (e.g., carbonic anhydrase), and (iii) genes containing regulatory motifs and/or homologies (three clones out of the 20 identified). The latter genes encode a zinc-finger-containing protein, a putative protein kinase, and a Wilm's tumor (WT) suppressor homologue, respectively. Expression of the kinase and WT suppressor homologues was induced early in nodulation, although the latter was activated transiently. Accumulation of the Zn-finger gene transcripts was detected at a later stage of development and seems to be regulated in a complex manner. Hence, using a cold-plaque screening procedure, we could identify genes that may play regulatory roles in the signal transduction pathways activated during nodule development.

Amino Acid Sequence↗
PubMed1998

Gastric cancer and Helicobacter pylori: biologic and epidemiologic inconsistencies.

In this report we examine biologic and epidemiologic data with the aim of understanding any correlations between Helicobacter pylori infection and preneoplastic and neoplastic changes. As far as biologic data are concerned, some elements point to the role of H. pylori in the development of preneoplastic and neoplastic changes, such as intestinal metaplasia and dysplasia. The relationship with H. pylori would mainly be due to an increased cellular proliferation with the presence of immature cells in the superficial layers, susceptible to metaplastic or dysplastic modifications. The subsequent passage toward cancer is probably caused by other factors inasmuch as H. pylori is not able to colonize metaplastic or dysplastic areas and hyperproliferation remains at comparable levels, even in the absence of infection. In fact, available epidemiologic data show a high prevalence of H. pylori infection in some geographic areas with a high incidence of gastric cancer. It is also true, however, that there are several populations in which a low neoplastic risk is associated with a high prevalence of infection. We stress the methodologic weaknesses of several studies that attempt to establish a strict association between cancer and H. pylori. Therefore, epidemiologic data are still contradictory and do not permit identifying a precise role of H. pylori as a predominant causative agent in the onset of preneoplastic and neoplastic changes. We conclude that H. pylori behaves as a possible cofactor of other known damaging agents to the gastric mucosa, contributing to the risk of developing neoplastic modifications that may also be subject to individual genetic susceptibility.

Gastrointestinal Neoplasms↗
PubMed1998

Helicobacter pylori and gastric cancer: what is the real risk?

Some epidemiological data point to an association between infection from Helicobacter pylori (Hp) and gastric cancer, although several unresolved issues still cast doubts on the real weight of this association. These issues are as follows: the male-to-female ratio of gastric cancer ranges from 4:1 to 1.5:1 in all studies, whereas the prevalence of Hp infection is the same in both sexes; the prevalence of Hp infection is as high as 90% in several developing countries where the frequency of gastric cancer is very low; the acquisition of the infection at a young age, considered very important with regard to the risk for cancer, varies from 4.2% to 83% in several countries in which the mortality for stomach cancer is approximately 10 in 100,000; and the incidence of cancer in patients with a duodenal ulcer is half that of the general population, but Hp infects up to 100% of these patients. In the sequence of events that leads to gastric cancer, Hp appears to play a role only in the very initial steps, as a causative agent of chronic inflammation. The further events that cause gastric atrophy, intestinal metaplasia, dysplasia, and cancer are multifactorial, involving environmental agents and the host response. It is therefore inappropriate to consider Hp a direct carcinogen for humans. This also applies to specific strains of the bacterium such as the cagA gene. In fact, Hp infection is widespread in humans, and only a small minority will ever be affected by peptic ulcer and cancer.

Adenocarcinoma↗
PubMed1997

enod40 induces dedifferentiation and division of root cortical cells in legumes.

Under nitrogen-limiting conditions Rhizobium meliloti can establish symbiosis with Medicago plants to form nitrogen-fixing root nodules. Nodule organogenesis starts with the dedifferentiation and division of root cortical cells. In these cells the early nodulin gene enod40, which encodes an unusually small peptide (12 or 13 amino acids), is induced from the beginning of this process. Herein we show that enod40 expression evokes root nodule initiation. (i) Nitrogen-deprived transgenic Medicago truncatula plants overexpressing enod40 exhibit extensive cortical cell division in their roots in the absence of Rhizobium. (ii) Bombardment of Medicago roots with an enod40-expressing DNA cassette induces dedifferentiation and division of cortical cells and the expression of another early nodulin gene, Msenod12A. Moreover, transient expression of either the enod40 region spanning the oligopeptide sequence or only the downstream region without this sequence induces these responses. Our results suggest that the cell-specific growth response elicited by enod40 is involved in the initiation of root nodule organogenesis.

Journal Article↗
PubMed1997

Cloning of a WD-repeat-containing gene from alfalfa (Medicago sativa): a role in hormone-mediated cell division?

Rhizobium meliloti can interact symbiotically with Medicago plants thereby inducing the formation of root nodules. Screening of a young nodule cDNA library led to the isolation of a cDNA from Medicago sativa, Msgbl, that comprises a new member of the RACK1 (Receptor of Activated C Kinase) subfamily of WD-repeat proteins. This subfamily shows homology to the beta-subunit of heterotrimeric G proteins. Besides RACK1, this subfamily contains several plant genes including the well characterized auxin-inducible ArcA of tobacco. The Msgbl gene is strongly expressed in young embryos and in leaves, and is induced upon cytokinin treatment of roots. Whereas northern analysis failed to reveal differences in expression between total RNA from roots and nodules, in situ hybridization demonstrated that the transcript was most abundant in dividing cells of nodule primordia and in the nodule meristem. Msgbl may be related to the signal transduction acting in response to hormone-mediated cell division.

Amino Acid Sequence↗
PubMed1997

A carbonic anhydrase gene is induced in the nodule primordium and its cell-specific expression is controlled by the presence of Rhizobium during development.

Under nitrogen starvation, Rhizobium meliloti is able to induce nitrogen-fixing nodules on alfalfa roots. Certain alfalfa cultivars spontaneously develop pseudonodules in the absence of bacteria. A transcript, Msca1, expressed in spontaneous and R. meliloti-induced nodules, that codes for a carbonic anhydrase (CA), an enzyme catalyzing the hydration of CO2 has been identified. This is the first CA gene cloned from a non-photosynthetic tissue in plants. Msca1 was activated initially in all cells of the bacterium-induced nodule primordium and was also induced by cytokinin treatment of alfalfa roots. The presence of CA enzymatic activity in different nodule types was demonstrated. Thus, Msca1 is a new early nodulin gene with a function possibly related to the increased amyloplast deposition of the dividing cortical cells. Msca1 transcripts were subsequently found mainly in a peripheral envelope of cells in developing and mature nodules. This novel pattern of gene expression is controlled by the presence of the bacterium inside the nodule. Sucrose synthase and phosphoenol pyruvate carboxylase (PEPC), other genes of the carbon fixation metabolism, were expressed in the same peripheral cells and even more strongly in the nitrogen-fixing region. Analysis of expression patterns of these genes indicated that early CA function may not be related to carbon fixation through PEPC. CA might be acting in pH regulation and/or CO2/HCO3-transport during nodule initiation. Thus, carbonic anhydrase may play different roles at several stages of nodule development and function.

Amino Acid Sequence↗
PubMed1997

Medium-large polyps of the colon: a contribution for their clinical profile and a proper surveillance.

A retrospective analysis of polypoid lesions of the colon larger than 1 cm was performed with the aim to study their characteristics and a proper surveillance schedule. We reviewed all colon polypoid lesions larger than 1 cm found and treated during the period January 1984- December 1993 that were not considered cancer macroscopically. The records of 361 patients with 391 polyps are the object of this report. The polyps were divided into subgroups according to size: A) less than 20 mm, B) between 21 and 30 mm, and C) larger than 30 mm. Out of 391 polypoid lesions 373 were adenomas: 60% were found in males. The age group distribution showed no differences among the subgroups. The pedunculated type showed a decrease from 69.1% to 43.3% with the increasing of size: inverse figures were observed for sessile polyps. The lesions were mainly located in left colon. Synchronous adenomas were found in 25.4% patients, and metachronous and previous adenomas respectively in 24.8% and 5.2%: no significant difference was present in the subgroups. Synchronous malignancy in the colon was found in 2% of the patients. Histological characteristics demonstrated a decrease of tubular adenoma from 46.5% to 22.6% from subgroup A to C, while villous adenomas increased inversely from 6.6% to 15.1%. The presence of severe dysplasia ranged from 20.9% to 56.1% in subgroups A and C, respectively, and adenomas with invasive cancer showed a significant increase from the subgroup A to C, respectively from 4.3% to 10.5%. During an average 36-month follow-up we observed 2 metachronous colon cancers, surgically treated in Dukes stage B, 84 metachronous adenomas, all less than 10 mm and without malignant alterations. Our data confirm other literature reports regarding the profile of colon adenomas with an increasing risk of malignancy with the increase of size and the presence of villous structure. In our opinion the assessment of a "clean colon" status is important when an adenoma is found in the colon. The proper follow-up for adenomas must be tailored for any individual patient when risk factors such as size, villous structure, personal and family history of neoplastic lesions of the colon are present. The follow-up schedule, presently recommended for colon adenomas, must be flexible according to these parameters.

Adenoma↗
PubMed1996

Dietary profiles and anti-oxidants in a rural population of central Italy with a low frequency of cancer.

This descriptive, cross-sectional study reports the anti-oxidant activities of a population sample of 736 individuals, randomly selected from residents of two small towns of the Latina province of Italy (an area at low frequency of cancer). The circulating levels of vitamins A, C and E, ceruloplasmin, carotenoids (lutein + zeaxanthin, lycopene, alpha- and beta-carotene, cryptoxanthin), cholesterol, high-density lipoprotein cholesterol and triglycerides, as well as anthropometric measurements (skin-folds, height, weight) were evaluated. A dietary interview was also performed by means of a semi-quantitative questionnaire. All the anti-oxidants were above the cut-off points for normality, whereas body mass index, % fat and serum lipids were not clearly suggestive of a protected population. The data obtained could be useful to estimate the baseline values of protective microelements and to assess dietary profiles in populations following a Mediterranean diet.

Adolescent↗
PubMed1995

Prevalence of Helicobacter pylori infection and gastritis among young adults in China.

To investigate the prevalence of gastritis and H. pylori infection among young Chinese in Henan Province, a high incidence area for oesophageal cancer in China, the gastric mucosa was examined in 194 asymptomatic subjects, aged 15-26 years, in the course of an epidemiological study of precursor lesions of oesophageal cancer. Histopathological grading of gastritis and determination of H. pylori infection were performed on haematoxylineosin and Warthin-Starry stained section. An enzyme-linked immunosorbent assay was used to detect the presence of serum IgG antibodies to H. pylori. A very high prevalence of gastritis (93.8%) was found: 71 subjects (36.6%) presented with superficial gastritis (14 active), 94 (48.5%) with diffuse gastritis (92 active) and in 17 cases (8.8%) diffuse gastritis (16 active) was accompanied by focal atrophy. Silver staining detected H. pylori in 166 (85.6%) of the study participants. However, serological techniques identified H. pylori in only 109 (56.2%). H. pylori was seen in all the 119 cases showing histological signs of active gastritis, in 41 of the 63 cases (65%) without activity, and also in 50% (6/12) of histologically normal subjects. H. pylori infection was found to be associated with a 2.5-fold higher prevalence of chronic atrophic gastritis compared with non-atrophic gastritis. A family history of stomach cancer, consumption of pickled vegetables more than twice a month, and a high monthly salt consumption (> 500 g/month) also showed a positive association.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Cancer risk related to uncommon migration within Italy.

AIMS AND BACKGROUND: Given the industrialization in Italy over this past century much migration has occurred within the country especially from southern to northern regions. Following repeated drainings of the pre-existing marsh area (Pontina plain) during the 1930s the Latina province received an unusual north-south immigration from the regions of Veneto, Friuli and Emilia Romagna. This consisted principally of manual workers, farmers and their families. Four new towns developed after a few years (Littoria, later renamed Latina, Sabaudia, Pontinia and Aprilia), and the whole province quickly reached a population of 60,000. The availability of a population-based Cancer Registry in the Latina province allowed us to assess the cancer risk in this migrant population. METHODS: Standardized Incidence ratios (SIRs) according to cancer site and sex were computed for residents over the age of 55 years, born in northern Italy. Population data, by sex, age and region of birth were based on the 1981 census. The age-sex-site specific incidence rates for the 1983-1987 period for the entire population of the Latina province over 55 years of age were used as standard. RESULTS: A significant excess of cancer risk for subjects of both sexes born in northern Italy was found. In addition, a statistically significant higher risk was observed for the cancers of the lung, skin (non-melanomas) and prostate in males, and of the mouthpharynx, lung and skin (non-melanomas) in females. CONCLUSIONS: SIRs for all sites confirm the findings from other studies on migrants in Italy and strongly support the hypothesis that the place of birth has an important influence on the frequency of cancer. Some possible etiological factors are suggested for cancer sites with higher frequencies in northern-born subjects.

Aged↗
PubMed1994

The fas operon of Rhodococcus fascians encodes new genes required for efficient fasciation of host plants.

Three virulence loci (fas, att, and hyp) of Rhodococcus fascians D188 have been identified on a 200-kb conjugative linear plasmid (pFiD188). The fas locus was delimited to a 6.5-kb DNA fragment by insertion mutagenesis, single homologous disruptive recombination, and in trans complementation of different avirulent insertion mutants. The locus is arranged as a large operon containing six open reading frames whose expression is specifically induced during the interaction with host plants. One predicted protein is homologous to P-450 cytochromes from actinomycetes. The putative ferredoxin component is of a novel type containing additional domains homologous to transketolases from chemoautotrophic, photosynthetic, and methylotrophic microorganisms. Genetic analysis revealed that fas encodes, in addition to the previously identified ipt, at least two new genes that are involved in fasciation development, one of which is only required on older tobacco plants.

Alkyl and Aryl Transferases↗