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Biomedical subjects

G Grandi

Publications and source records attributed to G Grandi.

At least 73 records · Page 4Linked to original sources
PubMed1991

Expression of Bordetella pertussis fimbrial (fim) genes in Bordetella bronchiseptica: fimX is expressed at a low level and vir-regulated.

To identify the elements involved in Bordetella pertussis fimbriae regulation and to determine whether fimX is an expressed gene, the promoter regions of fimX, fim2 and fim3 from strain BPSA1 were isolated and linked to the promoterless CAT gene in pLAFR2. By following CAT activity in Bordetella bronchiseptica vir+ and vir- strains we established that the fimX promoter, like those for fim2 and fim3, is active, although at a low level, and vir-regulated. This suggests that the fimX protein might be produced in minute quantities which are not detectable by conventional methods. Comparison of the three fim promoter sequences and transcriptional activities identifies two conserved elements necessary for transcription in the -60 to -20 region: the 'fim box' and the 'C-stretch'. Mutations in these two sequences drastically reduce transcription and alter the interaction with vir components, suggesting a role for the two elements in the regulation of fim genes. Finally, we suggest that the apparent constitutive nature of fim3 in BPSA1 is due to a modification in the length of the 'C-stretch'.

Base Sequence↗
PubMed1991

Intracranial metastases from malignant pleural mesothelioma. Report of three autopsy cases and review of the literature.

We report three cases of brain metastases from malignant pleural mesothelioma that were seen at autopsy. We present a summarized review of 15 similar reports that were previously published. Our study included three aged male patients with a long occupational history of heavy asbestos exposure. In two patients, the metastases were discovered incidentally at autopsy, and there were no neurologic symptoms referred to before death. In the other patient, who had clinically occult mesothelioma, the intracranial tumor was discovered ante mortem: in this patient, the clinical features, as well as a computed tomographic scan, suggested a primary tumor of the brain. Interestingly, the histologic features of the latter case that were seen at autopsy depicted a spindle cell tumor that focally exhibited pseudopalisading, necrosis, vascular buds, which deceptively recalled a glioblastoma. All the three cases shared a basic sarcomatous pattern of malignant pleural mesothelioma in both primary and metastatic tumors. The immunohistochemical profile was consistent with such interpretation. It was concluded that metastases to the brain from malignant pleural mesothelioma, although rare, are not exceptional even if their clinical relevance is not prominent. They are seen concomitantly with high-grade tumors, and by mimicking a primary tumor on a clinical, instrumental, and histologic ground, they may occasionally represent a potential source of diagnostic pitfall.

Adult↗
PubMed1990

Structural features of neutral protease from Bacillus subtilis deduced from model-building and limited proteolysis experiments.

The overall folding of neutral protease from Bacillus subtilis has been predicted by computer-aided modelling, taking as a basis the known three-dimensional structure of thermolysin. As expected from the 50% similarity of sequence between the two proteins, the structure of B. subtilis protease is similar to that of thermolysin, including the two-domain topology and location of elements of regular secondary structure (helices and strands), whereas specific differences were predicted in loop regions. A protruding and loose loop predicted in B. subtilis has been detected also experimentally by a limited proteolysis approach. Incubation of B. subtilis protease at pH 9.0 for 24 h at room temperature with trypsin at 20:1 ratio (by mass) leads to a specific and almost quantitative fission of the Arg214-Asn215 peptide bond located in a highly exposed, and thus probably flexible, loop of the protease. On the other hand, thermolysin was completely resistant to tryptic hydrolysis when reacted under identical conditions. The 'nicked' B. subtilis protease can be isolated by gel filtration chromatography at neutral pH, whereas the two constituting fragments 1-214 and 215-300 are separated under protein-denaturing conditions. Overall, these results indicate that the limited proteolysis approach can pinpoint a peculiar difference in surface structure between the two similar protein molecules of B. subtilis neutral protease and thermolysin and emphasize the potential use of proteolytic enzymes as structural probes of globular proteins.

Amino Acid Sequence↗
PubMed1990

Colostomy irrigation in the elderly. Effective recovery regardless of age.

One hundred forty elderly cancer outpatients with colostomy in the authors' rehabilitation department were included in an analysis of the feasibility, effectiveness, and safety of periodic irrigation of remaining colon with lukewarm tap water with the aim of regaining full continence. Sixteen patients did not have a sufficiently long remaining bowel (cecostomy, transverse colostomy) and 17 were considered unsuitable to learn the technique because of advanced neoplastic disease with poor life expectancy, intercurrent disease, or stomal problems. One hundred seven patients were proposed to perform the irrigation: 17 refused to do so with the remaining 90 able to learn the method without problems. Nearly all patients achieved full continence for at least 24 hours. Three patients refused to continue, and nine interrupted for minor complications. The median duration of irrigation in the whole group is 257 days (range, 1 to 2669 days): 32 patients have been irrigating from one to five years, and 9 patients for more than 5 years. Based on these results, we recommend irrigation as standard rehabilitative treatment for elderly patients.

Age Factors↗
PubMed1990

Histopathology in Atherina boyeri (Pisces: Atherinidae) resulting from infection by Telosentis exiguus (Acanthocephala).

The histopathology developing in the sand smelt Atherina boyeri Risso 1810 from Northern Italy as the result of a natural infection by Telosentis exiguus Von Linstow 1901 (Acanthocephala) was studied and described. Microscope examination of sections of intestinal tissues showed that the parasites did not penetrate through all intestinal layers, and that damage was mostly limited to the epithelium.

Acanthocephala↗
PubMed1990

[Effect of hysterectomy and ovariectomy on the incidence of malignant neoplasms of the female genital tract].

The true risk population for uterine and ovary cancer have been studied, according to the prevalence of histerectomy and oophorectomy in the Trieste area female population. The calculation of the females at risk for these tumors permits to recalculate the incidence rates that are usually underestimated. This adjustment increases the rates in all genital tract tumors from 14% to 18%, but does not modify the relative frequency per age groups or the incidence in the temporal trends. An exception is represented from the uterine corpus cancer in which the correction of the population modifies the temporal trend for the age group over 60 years. The incidences tend in fact to increase significantly more after the adjustment.

Female↗
PubMed1989

Effect of Glu-143 and His-231 substitutions on the catalytic activity and secretion of Bacillus subtilis neutral protease.

On the basis of the homology with the Bacillus thermoproteolyticus zinc endopeptidase thermolysin, we hypothesized that Glu-143 and His-231 are the key residues for the catalytic activity of the Bacillus subtilis neutral protease. To test this possibility by site-directed mutagenesis, we substituted these two residues with Ala, Ser, Trp and Arg, and Leu, Val and Cys respectively. All these substitutions dramatically affected the amount of secreted mutant proteins, as determined by immunological methods, and their catalytic activities. No appreciable secretion was observed with the three Glu mutants Trp, Ser and Arg, whereas the Glu----Ala mutant enzyme was secreted at a level of a few hundred micrograms per litre of culture. The His mutants were all secreted at higher levels (in the order of a few milligrams per litre) and their residual catalytic activity could be determined using Z-Ala-Leu-Ala as substrate. Our results confirm the key role played by Glu-143 and His-231 in catalysis and moreover suggest the existence of a relationship between the catalytic activity of the enzyme and the extent of its secretion. In this context, we present data suggesting an autoproteolytic mechanism of cleavage of the precursor form of the enzyme, analogous to the one previously reported for the B. subtilis subtilisin.

Amino Acid Sequence↗
PubMed1989

Cloning and nucleotide sequence of the isoamylase gene from a strain of Pseudomonas sp.

A strain of Pseudomonas sp., SMP1, isolated from a soil sample collected in the Monterotondo area (Rome), secreted isoamylase activity into the culture medium. The enzyme was purified and optimal reaction and stability conditions were determined by varying pH and temperature. The chemico-physical properties of the enzyme were similar to those of the isoamylase purified in Japan more than 20 years ago from 'Pseudomonas amyloderamosa' strain SB15. A genomic library of SMP1 was prepared in Escherichia coli using pUC12 as vector. Two isoamylase-producing colonies were identified out of 6300 screened. The hybrid plasmids isolated from the two clones showed common restriction patterns. The chromosomal portion of one of these plasmids (pSM257) was completely sequenced. Comparison between the deduced amino acid sequence of the isoamylase and the published sequences of other amylolytic enzymes showed the presence of conserved domains.

Amino Acid Sequence↗
PubMed1989

The pathology of optic nerve aging.

The pathology of the optic nerve in the advanced elderly has been investigated at autopsy in a sample of 50 subjects (43 males, 7 females), aged 95-103 years. Septal fibrous thickness and slendering of nerve fibers were the most frequently encountered lesions as well as degenerative processes involving the cribriform lamina. Other significant features included gliosis, demyelination, and corpora amylacea. Complete arteriosclerotic disease was rarely observed. The results of the present study suggest that optic nerve pathology in aged people is almost the consequence of an inadequate blood supply; nevertheless, the degree of these lesions does not seem to parallel that usually observed in other sites particularly injured by ischemic disease.

Aged↗
PubMed1988

A rapid and versatile site-directed method of mutagenesis for double-stranded plasmid DNA.

This paper describes a new method for site-directed mutagenesis which allows mutations by deletion, insertion or substitution of large fragments of DNA with more than 50% efficiency and does not require subcloning in a single-stranded (ss) DNA vehicle. The site of mutagenesis is removed from a linearized plasmid DNA by BAL 31 digestion, ss DNA regions are generated by limited exonuclease treatment and the mutated target site is reconstituted by annealing of the plasmid DNA to a 35-70 nucleotide long mutated ss oligodeoxynucleotide containing the desired mutation. The circularized plasmid is finally used to transform directly Escherichia coli competent cells.

Base Sequence↗
PubMed1988

Cloning of a novel pilin-like gene from Bordetella pertussis: homology to the fim2 gene.

A search for pilin genes in a Bordetella pertussis (Bp) genomic library has led to the identification of several clones which hybridize to synthetic oligonucleotides with sequences derived from amino acid sequences of Bp fimbrial subunits. One of these clones (corresponding to a gene we have named fimX) contains an open reading frame encoding a protein with a molecular weight of about 20 kD and a sequence similar but not identical to the fimbrial subunit fim2 and to other fimbrial protein sequences. In this communication we present the cloning and nucleotide sequence of the fimX gene and its homology to the fim2 gene. A genomic analysis on the positional relationship between the two genes is also presented.

Amino Acid Sequence↗
PubMed1988

Bordetella pertussis pilin and pilin-like genes.

Bordetella pertussis fimbriae, which mediate the adherence of the microorganism to the epithelium of the respiratory tract, elicit a protective immunogenic response which could be taken advantage of for the creation of an acellular vaccine against pertussis. A few of the fimbrial proteins have been partially characterized by immunological means which recently the cloning and characterization of pilin and pilin-like genes are allowing us to study their structure, regulation of expression during the infectious cycle of Bordetella pertussis, and the basis for antigenic variation. In this communication we will review recent data on Bordetella pertussis pilin and pilin-like genes and their products, with particular emphasis on data most relevant to the design of an acellular vaccine.

Amino Acid Sequence↗
PubMed1987

Testis cytological structure, plasma sex steroids, and gonad cytosol free steroid receptors of heterologous gonadotropin (hCG)-stimulated silver eel, Anguilla anguilla L.

Complete testicular maturation was induced in silver eels, kept at 24 degrees in fresh water, by a single injection of 1000 I.U. of heterologous gonadotropin (hCG). Each week, for 4 weeks, some eels were examined for testis structural pattern, plasma sex steroids, and gonad cytosol steroid receptors. The first effect of the hCG was on the tubular organization of the testis, followed by spermatogenesis. Plasma androgens were not detectable in the untreated eels, whereas a peak was detected a week after in those treated with the injection and afterward a decline. Plasma progesterone and estradiol showed a peak 2 weeks after treatment. Untreated eel gonads showed a high content of cytosolic free estradiol receptors which disappeared in the hCG-treated ones, a peak of free progesterone receptors was found 1 week after injection. The results are discussed in relation to the differentiation and maturation of eels testes.

Anguilla↗
PubMed1987

Localization of beta-hydroxysteroid dehydrogenase in Anguilla anguilla testis.

The histochemical reaction for 3 beta-hydroxysteroid dehydrogenase was applied to glutaraldehyde fixed eel testis and successively processed for transmission electron microscopy. The reaction product was found only on the smooth endoplasmic reticulum and in the intermembrane space of mitochondria of the Leydig cells of hCG treated silver eels. The positive cytochemical reaction appears to be coupled with an enlargement of the Leydig cells and an increase of their smooth endoplasmic reticulum.

3-Hydroxysteroid Dehydrogenases↗