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Biomedical subjects

G Grandi

Publications and source records attributed to G Grandi.

At least 91 records · Page 5Linked to original sources
PubMed1986

New plasmid expression vectors for Bacillus subtilis.

The construction of new cloning vectors for Bacillus subtilis is described. They are derived from the in vitro joining of parts of pE194 and pUB110 DNAs. Their common feature is to present a cloning site immediately after the promoter and ribosome binding site of the erythromycin resistance gene, allowing the insertion and expression of either sticky or blunt ended DNA fragments coding for any heterologous gene. The cloning and expression of Escherichia coli beta-lactamase and EcoRI methylase are given as examples. The enzymes are efficiently synthesized by B. subtilis cells.

Bacillus subtilis↗
PubMed1986

Reliability of death certifications for different types of cancer. An autopsy survey.

A series of 1000 cases was selected, on the basis of a clinical and/or post-mortem diagnosis of cancer, out of 4927 autopsies performed at the Institute of Pathologic Anatomy and Histopathology of Turin University. The comparison between clinical and post-mortem diagnoses pointed to an overall concordance with regard to the correct identification of a malignancy as the underlying cause of death of 75%; if the correct identification of type and primary site of the tumor was also taken into account, the concordance was only 56%. The rate of false-positive and false-negative diagnoses, the confirmation rate and sensitivity index of clinical diagnoses, and the error of estimate of the overall frequency of the different types of tumors were computed. Pancreas, liver and biliary tract tumors appear to be the most difficult to identify correctly during life; also lung, stomach and colorectal cancers, lymphomas and leukemias show fairly high rate of clinical errors. Breast cancer, tumors of the nervous system and colorectal cancers appear to be overnotified. These results seem to underscore the necessity of being very careful in drawing conclusions on the frequency and distribution of the different types of cancer on the basis of current mortality statistics.

Age Factors↗
PubMed1986

nprR1 and nprR2 regulatory regions for neutral protease expression in Bacillus subtilis.

The gene coding for the Bacillus subtilis extracellular neutral protease was isolated from strain BGSC 1A341, an overproducer carrying the nprR2 region, and from strain 168, a normal producer with the nprR1 sequence. The sequence of about 600 nucleotides upstream from the start codon of the protease gene was determined for both strains. The two regions are highly homologous except for a stretch of 66 base pairs close to the promoter region, which is absent in the BGSC 1A341 gene. Northern blot analysis of the in vivo RNAs indicated that the different levels of enzyme secreted by the two strains were due to different amounts of transcripts that accumulated in the cells. Furthermore, at the end of exponential growth, the amount of transcript increased dramatically in the overproducer strain but remained approximately constant in the normal producer strain. The start point(s) for transcription, however, as determined by S1 nuclease mapping of the in vivo transcripts, appeared to be the same for both genes.

Bacillus subtilis↗
PubMed1986

Optic nerve in diabetes mellitus: a case control study.

The pathology of optic nerve in 80 diabetic subjects has been investigated in a morphologic study performed on autoptic material. Gliosis and demyelination resulted as the most frequently observed lesions (respectively 19 and 18 cases) and were associated to long history of diabetes. Additional findings were focal infarctions, atrophy, and broad spectrum of vascular lesions, mostly affecting the microcirculation, including thickening, hyalinosis, microaneurysms, as well as thromboses. An age-sex-matched control group, made of non diabetic subjects, did not share significantly lesions with the diabetics. Therefore, the authors suggest that diabetes mellitus plays an important role in the development of pathological changes in the optic nerves, thus claiming the marked vascular damage of early age onset diabetes as a possible pathogenetic factor.

Aged↗
PubMed1983

Bilateral follicular basal cell nevus with comedo-like lesions.

A 12-year-old white boy presented with symmetrically appearing papular, nodular, comedo-like, highly itching lesions involving the skin on his ankles. They had first appeared 3 years earlier. Numerous cutaneous biopsies showed tumoral buds of basalioma cells associated with follicular structures, infundibular cysts and also hypertrophy and hyperplasia of sebaceous glands. To the best of our knowledge, there are no reported cases with the same clinical and histopathological findings as in those reported here. We believe the lesions represent a "bilateral follicular basal cell nevus with comedones".

Ankle↗
PubMed1982

Translational attenuation of ermC: a deletion analysis.

ermC is a plasmid gene which specifies resistance to macrolide-lincosamide-streptogramin B antibiotics. The product of ermC was previously shown to be an inducible rRNA methylase, which is regulated translationally, and a mechanism for this regulation, termed the translational attenuation model, has been proposed. This model postulates that alternative inactive and active conformational states of the ermC mRNA are modulated by erythromycin-induced ribosome-stalling during translation of a leader peptide. In the present study the translational attenuation model was tested by constructing a series of deletants missing the ermC promoter and portions of the regulatory (leading) region. In these mutants, ermC transcription is dependent on fusion to an upstream promoter. Depending on the terminus of each deletion within the regulatory region, determined by DNA sequencing, ermC expression is observed to be either high level and inducible (like the wild-type), high level and noninducible, or low level and noninducible. The translational attenuation model predicts that as the deletions extend deeper into the leader region, successively masking and unmasking sequences required for translation of the methylase, an alternation of high and low level methylase expression will be observed. These predictions are confirmed. Based on this and other information, the model is refined and extended, and both direct translational activation and kinetic trapping of a metastable active intermediate during transcription are proposed to explain basal synthesis of methylase and to rationalize the effects of certain regulatory mutants.

Bacillus subtilis↗
PubMed1981

Melanosis cerebelli.

Melanosis cerebelli (melanic pigmentation involving the dentate nuclei and the granular layer of the cerebellar cortex) is described in three patients, aged between 72 and 99 years. In two cases atrophic changes of the Alzheimer type co-existed in the cerebral cortex. One patient had a history of tremors, possibly cerebellar in origin.

Aged↗
PubMed1981

Naturally occurring macrolide-lincosamide-streptogramin B resistance in Bacillus licheniformis.

Resistance to the macrolide-lincosamide-streptogramin B (MLS) group of antibiotics is widespread and of clinical importance. B. Weisblum and his coworkers have demonstrated that this resistance is associated with methylation of the 23S ribosomal ribonucleic acid of the large ribosomal subunit which results in a diminished affinity of this organelle for these antibiotics (Lai et al, J. Mol. Biol. 74:67-72, 1973). We report that 10 of 15 natural isolates of Bacillus licheniformis, a common soil organism, are resistant to the MLS antibiotics. The properties of this resistance (high level of tolerance for erythromycin, broad cross-resistance spectrum, and inducibility) suggest that resistance is conferred as described above. The resistance determinant from one of these strains was cloned onto a B. subtilis plasmid vector, and the resulting hybrid plasmid (pBD90) was used to prepare radioactive probe deoxyribonucleic acid for hybridization studies. All of the resistance B. licheniformis strains studied exhibited homology with the pBD90 insert. Plasmid pBD90 showed no homology to the following staphylococcal and streptococcal MLS-resistance plasmids: pE194, pE5, pAM77, pI258. Plasmids pE194 and pE5, on the other hand, carry homologous MLS genes but showed no detectable homology to one another in their replication genes. pBD90 specified a 35,000-dalton erythromycin-inducible protein, detectable in minicells, which therefore appears different from the 29,000-dalton inducible resistance protein specified by pE194. We conclude that there are at least three distinct MLS resistance determinants to be found among gram-positive bacteria.

Anti-Bacterial Agents↗
PubMed1980

Conformational alteration of mRNA structure and the posttranscriptional regulation of erythromycin-induced drug resistance.

The DNA sequence of the ermC gene of plasmid pE194 is presented. This determinant is responsible for erythromycin-induced resistance to the macrolide-lincosamide-streptogramin B group of antibiotics and specifies a 29,000 dalton inducible protein. The locations of the ermC promoter, as well as that of a probable transcriptional terminator, are established both from the sequence and by transcription mapping. The sequence contains an open reading frame sufficient to encode the previously identified 29,000 dalton ermC protein. Between the promoter and the putative ATG start codon is a 141 base pair leader sequence, within which several regulatory (constitutive) mutations have been mapped and sequenced. The leader has a second open reading frame, sufficient to encode a 19 amino acid peptide. It is suggested that induction by erythromycin involves a shift between alternative ribosome-bound mRNA conformations, so that the ribosome binding sequence and the start codon for synthesis of the 29K protein are unmasked in the presence of inducer. Possible active and inactive folded configuration of the leader sequence are presented, as well as the effects on these configurations of regulatory mutations.

Bacillus subtilis↗
PubMed1980

Posttranscriptional regulation of an erythromycin resistance protein specified by plasmic pE194.

Induction of the synthesis of a plasmid-encoded polypeptide (E3) by erythromycin is known to be required for the inducible expression of resistance to the macrolide-lincosamide-streptogramin B group of antibiotics in Bacillus subtilis strains carrying the plasmid pE194. This resistance is mediated by a specific N6-dimethylation of adenine in the 23S rRNA of the large ribosomal subunit. We show in this report that E3 induction is regulated posttranscriptionally in the sense that it can occur when RNA synthesis is blocked and that induction is accompanied by an increase in the functional half-life of E3 mRNA but not of the mRNA species that code for the remaining four known pE194 polypeptides. The induction of E3 is subject to feedback regulation and involves the ribosome. Modification of the erythromycin binding site on the ribosome by methylation or by mutation interferes with induction.

Bacillus subtilis↗
PubMed1979

Different specific activities of the monomeric and oligomeric forms of plasmid DNA in transformation of B. subtilis and E. coli.

(1) The low residual transforming activity in preparations of monomeric, supercoiled, circular (CCC) forms of the plasmids pC194 and pHV14 could be attributed to the presence in such isolates of a small number of contaminating multimeric molecules. (2) E. coli derived preparations of pHV14, as in vitro recombinant plasmid capable of replication in both E. coli and B. subtilis, contain oligomeric forms of plasmid DNA in addition to the prevalent monomeric CCC form. The specific transforming activity of pHV14 DNA for E. coli is independent of the degree of oligomerization, whereas in transformation of B. subtilis the specific activity of the purified monomeric CCC molecules is at least four orders of magnitude less than that of the unfractionated preparation. (3) Oligomerization of linearized pHV14 DNA by T4 ligase results in a substantial increase of specific transforming activity when assayed with B. subtilis and causes a decrease when used to transform E. coli.

Bacillus subtilis↗
PubMed1978

[Pulmonary bone-marrow embolism. Analysis of 53 cases].

The medical record and the lung sections were reviewed in 53 autoptic cases with pulmonary bone marrow embolism. In 31 cases the emboli could be ascribed to external cardiac massage, in one case to accident; in the other cases a definite aetiologic factor was lacking. The number of the emboli was largely variable from one section to another and sometimes very high (up to 16). The pulmonary bone marrow embolism has probably a clinical significance particularly when the underlying condition is severe.

Adult↗
PubMedDate not supplied

Diffuse pleural mesothelioma in Trieste. A survey based on autopsy cases.

Records of necropsies performed at the Institute of Pathological Anatomy and Histology of the University of Trieste during the period December 1 1971-December 31 1977 have been reviewed. Cases with a necropsy diagnosis of pleural tumor or lung sarcoma were reexamined. Twenty-six cases were accepted as definite diffuse pleural mesothelioma. Occupational history was indicative of asbestos exposure in 22 cases, with 12 patients having worked in shipyards. The high incidence of diffuse pleural mesothelioma in the Province of Trieste is emphasized.

Aged↗