PubMed Health⌕ Search

Biomedical subjects

M de Rosa

Publications and source records attributed to M de Rosa.

15 recordsLinked to original sources
PubMed2004

[The current importance of veterinary public health: the SAPUVET project].

The authors propose reviewing the current needs for implementing veterinary public health programmes, from both the teaching and professional standpoints. This is warranted by the fact that veterinary public health has become extremely important in various fields of work, beyond conventional food inspection. The article discusses the public health role which veterinarians must play and the interactions between their activities and those of other groups such as doctors, epidemiologists, ecologists, chemists, or even sociologists and anthropologists. The authors also study and assess the basic working tool in veterinary public health--epidemiological surveillance--and how it operates on the basis of diagnosis and risk analysis. The second part of the article discusses the need to unify criteria for veterinary public health training and the role which the SAPUVET network is playing in doing so (SAPUVET is a European Union-supported project within the ALFA programme that is designed to establish links between Latin American and European veterinary faculties).

Animals↗
PubMed2001

Phenotype-genotype correlations in an extended family with adenomatosis coli and an unusual APC gene mutation.

PURPOSE: Genotype-phenotype correlations in familial adenomatous polyposis are only partially understood and, in particular, little is known about the biomolecular characteristics of desmoid tumors, which are one of the most serious and frequent manifestations of familial adenomatous polyposis. In the present study, we describe a family with familial adenomatous polyposis, with peculiar clinical characteristics (i.e., frequency and severity of desmoid neoplasms) associated with an unusual mutation of the adenomatosis polyposis coli gene. If confirmed by other investigations, these findings might help to understand the biologic mechanisms by which specific adenomatosis polyposis coli mutations predispose to desmoid tumors. METHODS: The family with familial adenomatous polyposis, living in southern Italy, was studied from 1985 to the end of 1999; at this date, 15 individuals have been affected by histologically verified familial adenomatous polyposis, 11 of whom had desmoid tumors. A total of 19 family members were studied for adenomatosis polyposis coli gene mutations; 13 of them tested positive and 6 negative. The analytical procedure-previously described-consisted of the extraction of peripheral blood cell DNA, amplification of exon 15 by polymerase chain reaction, single-strand conformation polymorphism analysis, and direct sequencing of the DNA fragment containing the mutation. RESULTS: The main clinical features of the family were 1) a high frequency of desmoid tumors and, consequently, a high penetrance of the desmoid trait in all branches of the family and in 11 (73.3 percent) of 15 affected individuals and 2) severity of desmoids in at least 4 family members, 2 of whom died for causes related to the presence of these tumors. The molecular basis of the disease was an uncommon mutation of the adenomatosis polyposis coli gene, consisting of a large deletion of 310 base pairs at codon 1,464, with duplication of the breakpoint (4,394ins15del310), leading to a stop codon at position 1,575. CONCLUSIONS: The present study shows that a truncating mutation in the adenomatosis polyposis coli gene at the beginning of the region frequently associated with desmoids induced a familial adenomatous polyposis phenotype featured by a high penetrance of the desmoid trait, with severe disease in several affected members of both sexes. The study may help to understand the biologic mechanisms of genotype-phenotype correlations in adenomatosis coli.

Adenomatous Polyposis Coli↗
PubMed2001

Innovative fermentation strategies for the production of extremophilic enzymes.

A new type of microfiltration (MF) bioreactor, developed in our laboratory, was investigated for use in improving efficiency of the production of extremophilic enzymes. In spite of the difficulties in cultivating hyperthermophiles, we achieved, in 300 h fermentation, more than 38 g/l dry weight of Sulfolobus solfataricus using a MF technique, and we demonstrated that the activity of alcohol dehydrogenase (ADH), as the reporter enzyme, was not affected by cell density. However, hyperthermophile cultivation is difficult to scale up because of evaporation and the very low growth rate. Thus, to achieve high productivity we cultivated, in the MF bioreactor, recombinant mesophilic hosts engineered for the production of two thermophilic enzymes, namely, trehalosyldextrin-forming enzyme (SsTDFE) and trehalose-forming enzyme (SsTFE) from Sulfolobus solfataricus. The traditional Luria-Bertani broth used for recombinant Escherichia coli growth was replaced with a semidefined medium. The latter was used in both the batch and the MF experiments, and the ratio of complex components (e.g., yeast extract and tryptone) to a simple carbon source (glycerol) was decreased during the fed-batch phase to further decrease the medium cost in view of industrial applications. The bioprocess developed was able to improve productivity 500 fold for rSsTFE and 60 fold for rSsTDFE with respect to the wild type cultivated in MF mode. Comparisons with another recombinant enzyme, alpha-glucosidase (rSsalphagly), from Sulfolobus solfataricus produced in our MF bioreactor are reported.

Bioreactors↗
PubMed2000

Repeatability of the ISAAC video questionnaire and its accuracy against a clinical diagnosis of asthma.

The objective of the study was to evaluate the performance of the International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire in terms of repeatability and accuracy against a clinical diagnosis of asthma achieved according to the National Heart, Lung and Blood Institute (NHLBI) algorithm. Two hundred and forty-one subjects, aged 13-14 years from two secondary schools in Rome, Italy, were enrolled. Video and written ISAAC questionnaires were completed twice, 3 months apart, by 194 and 190 adolescents, respectively. Two months later, 106 subjects were visited by two physicians blinded to the results of questionnaires. Sixteen subjects were classified as having clinical asthma (CA) at the clinical visit, and eight of them as having clinical active asthma (CAA) on the basis of at least one positive outcome of the NHLBI algorithm. The repeatability of video questionnaire was similar to that of the written questionnaire for items on exercise wheeze and nocturnal cough and, to a lesser degree, for items concerning any wheeze in the past. The video questionnaire showed a worse performance than the written questionnaire for items on asthma attack: K-value (95% CL) = 0.59 (0.37-0.80) for video scene no. 5 and K-value (95% CL) = 0.86 (0.74-0.98) for written question no. 6. The overall accuracy of the video questionnaire, estimated as a positive answer to any video scene, was lower in terms of sensitivity than that of any written question when CA was used as a gold standard (0.50 vs. 0.81, P=0.025) and increased with respect to CAA (0.75 vs. 0.87, P = 0.317). The specificity of any video scene was better than that of any written question, independently from the gold standard used. In conclusion, the video questionnaire showed a fairly good accuracy, although slightly lower than that of the written questionnaire and provided sufficiently reliable results. However, samples of subjects from different geographic areas and cultures should be studied in order to conclusively define the performance of the ISAAC video questionnaire.

Adolescent↗
PubMed1998

hMLH1 mutations in hereditary nonpolyposis colorectal cancer kindreds. Mutations in brief no. 182. Online.

Hereditary nonpolyposis colorectral cancer (HNPCC), an autosomal dominantly inherited predisposition for early onset colorectal cancer, accounts for at least 6% of all colorectal malignancies. HNPCC results from germ-line mutations in DNA mismatch repair (MMR) genes (hMSH2, hMLH1, hPMS1 and hPMS2) and is associated with a high rate of replication errors in tumor cells. Using PCR-SSCP, the protein truncation test and DNA sequencing we have analyzed the hMSH2 and hMLH1 genes in 10 Italian families that met the standard diagnostic criteria for HNPCC. We have identified three new mutations in the hMLH1 gene. One mutation consists in a deletion of one base pair at nucleotide 954 (954delC) in exon 11 that creates an early stop at codon 366 and is predicted to abolish normal protein function. The other two are missense mutations. Cys77Arg and Ser193Pro, that cause dramatic amino acid substitutions in two highly conserved MLH domains. The Cys77Arg mutation occurs within a domain (1-114 residues) that is very critical for MMR function. The Ser193Pro mutation occurs in a highly conserved central region of the MLH1 protein. No functional domains have yet been identified in this region. All mutant alleles cosegregate with the cancer phenotype.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Refolding of glutamate dehydrogenase from Bacillus acidocaldarius after guanidinium chloride-induced unfolding.

The hexameric NAD-dependent glutamate dehydrogenase from the thermophilic eubacterium Bacillus acidocaldarius is the first glutamate dehydrogenase which spontaneously refolds in vitro. After 24 h unfolding in 6 M guanidinium chloride at 20 degrees C, refolding was achieved by dilution of the denaturant. The yield of reconstitution obtained in the presence of 1,4 dithio-DL-threitol in the unfolding/refolding mixture was 75%. The unfolding/refolding equilibria have been studied by fluorescence, circular dichroism and catalytic activity, which was 50% inhibited at 0.08 M guanidinium chloride, a value 30-fold lower than the transition midpoint detected by physical changes. Refolding was attempted in the presence of various additives, at different temperatures and varying enzyme and residual guanidinium chloride concentration. The refolded enzyme, after removal of inactive aggregated species, completely resembles the native enzyme in term of its physicochemical and kinetic properties as well as thermophilicity.

Bacillus↗
PubMed1986

Glucose dehydrogenase from the thermoacidophilic archaebacterium Sulfolobus solfataricus.

Glucose dehydrogenase has been purified to homogeneity from cell extracts of the extreme thermoacidophilic archaebacterium Sulfolobus solfataricus. The enzyme utilizes both NAD+ and NADP+ as coenzyme and catalyses the oxidation of several monosaccharides to the corresponding glyconic acid. Substrate specificity and oxidation rate depend on the coenzyme present; when NAD+ is used, the enzyme binds and oxidizes specifically sugars presenting equatorial orientation of hydroxy groups at C-2, C-3 and C-4. The Mr of the native enzyme is 124,000 and decreases to about 60,000 in the presence of 6 M-guanidinium chloride and to about 30,000 in the presence of 5% (w/v) SDS. The enzyme shows maximal activity at pH 9, 77 degrees C and 20 mM-Mg2+, -Mn2+ or -Ca2+ and is fairly stable in the presence of chaotropic agents and water-miscible organic solvents such as methanol or acetone.

Amino Acids↗
PubMed1983

Secondary structure features of ribosomal RNA species within intact ribosomal subunits and efficiency of RNA-protein interactions in thermoacidophilic (Caldariella acidophila, Bacillus acidocaldarius) and mesophilic (Escherichia coli) bacteria.

Ribosomal subunits of Caldariella acidophila (max.growth temp., 90 degrees C) have been compared to subunits of Bacillus acidocaldarius (max. growth temp., 70 degrees C) and Escherichia coli (max. growth temp., 47 degrees C) with respect to (a) bihelical content of rRNA; (b) G . C content of bihelical domains and (c) tightness of rRNA-protein interactions. The principal results are as follows. Subunits of C. acidophilia ribosomes (Tm = 90-93 degrees C) exhibit considerable thermal tolerance over their B. acidocaldarius (Tm = 77 degrees C) and E. coli counterparts (Tm = 72 degrees C). Based on the "melting' hyperchromicities of the intact ribosomal subunits a 51-55% fraction of the nucleotides appears to participate in hydrogen-bonded base pairing regardless of ribosome source, whereas a larger fraction, 67-70%, appears to be involved in hydrogen bonding in the naked rRNA species. The G . C content of bihelical domains of both free and ribosome-bound rRNA increases with increasing thermophily; based on hyperchromicity dispersion spectra of intact subunits and free rRNA, the bihelical parts of C. acidophila rRNA are estimated to contain 63-64% G . C, compared to 58.5% G . C for B. acidocaldarius and 55% G . C for E. coli. The increment of ribosome Tm values with increasing thermophily is greater than the increase in Tm for the free rRNA, indicating that within ribosomes bihelical domains of the thermophile rRNA species are stabilized more efficiently than their mesophile counterparts by proteins or/ and other component(s). The efficiency of the rRNA-protein interactions in the mesophile and thermophile ribosomes has been probed by comparing the releases, with LiCl-urea, of the rRNA species from the corresponding ribosomal subunits stuck to a Celite column through their protein moiety; it has been established that the release of C. acidophila rRNA from the Celite-bound ribosomes occurs at salt-urea concentrations about 4-fold higher than those required to release rRNA from Celite-bound E. coli ribosomes. Compared to E. coli the C. acidophila 50 and 30 S ribosomal subunits are considerably less susceptible to treatment designed to promote ribosome unfolding through depletion of magnesium ions.

Bacillus↗
PubMed1982

Archaebacterial elongation factor Tu insensitive to pulvomycin and kirromycin.

A spermine-dependent, polyphenylalanine-synthesizing cell-free system having an optimum activity at 75-85 degrees C, has been developed from the extremely thermoacidophilic archaebacterium Caldariella acidophila. The C. acidophila system is totally insensitive to the EF-Tu targeted antibiotics pulvomycin (at 40 degrees C) and kirromycin (at 47-72 degrees C) contrary to control systems derived from both mesophilic (Escherichia coli) and thermoacidophilic (Bacillus acidocaldarius) eubacteria. The archaebacterial EF-Tu-equivalent factor is also immunologically unrelated to eubacterial EF-Tu and does not cross react with antibodies against Escherichia coli EF-Tu. The pulvomycin and kirromycin reactions thus provide new phyletic markers for archaebacterial ancestry.

Aminoglycosides↗
PubMed1975

Extremely thermophilic acidophilic bacteria convergent with Sulfolobus acidocaldarius.

A series of extremely thermophilic acidophilic bacteria has been characterized as closely resembling the species Sulfolobus acidocaldarius except for a totally different guanosine-cytosine content in the DNA; some conceptual consequences of this situation are discussed. Both organisms also share special features, including a very characteristic type of ether lipid, with other extreme acidophilic thermophiles.

Acetates↗
PubMed1975

Ultrastructure of an extremely thermophilic acidophilic micro-organism.

A thermoacidophilic micro-organism, isolated from volcanic hot springs near Naples, was cultivated in vitro, and examined by electron microscopy in sections and after negative staining. The cells were almost spherical, with a diameter of about 0.7 to 1.0 mum. Their morphology was very primitive: the protoplasm was composed only of ground cytoplasm, ribosomes, and randomly distributed DNA strands. They were surrounded by a plasma membrane and by an extracellular coat about 20 nm thick which displayed a regular hexagonal pattern. Cell replication occurred by binary fission with median constriction during which a bipolar localization of nuclear material was observable. The morphology is compared with that of other known micro-organisms living in similar habitats.

Bacteria↗