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Biomedical subjects

G Bertoni

Publications and source records attributed to G Bertoni.

At least 91 records · Page 5Linked to original sources
PubMed1992

Cloning and transposon vectors derived from satellite bacteriophage P4 for genetic manipulation of Pseudomonas and other gram-negative bacteria.

We developed transposon and cloning shuttle vectors for genetic manipulation of Pseudomonas and other gram-negative bacteria, exploiting the unique properties and the broad host range of the satellite bacteriophage P4. P4::Tn5 AP-1 and P4::Tn5 AP-2 are suicide transposon vectors which have been used for efficient Tn5 mutagenesis in Pseudomonas putida. pKGB2 is a phasmid vector with a cloning capacity of about 7.5 kb; useful unique cloning sites are SacI and SacII in the streptomycin resistance determinant and PvuI and XhoI in the kanamycin resistance determinant. pKGB4 is a cosmid derived from pKGB2 and carries the additional cloning site SmaI in the kanamycin resistance determinant; its cloning capacity is about 18 kb. These vectors and their recombined derivatives were transferred from Escherichia coli to P. putida by transduction and may be used for other bacterial species susceptible to P4 infection.

Coliphages↗
PubMed1992

Randomized placebo-controlled trial of oral liquid simethicone prior to upper gastrointestinal endoscopy.

It has been suggested that pre-procedural oral simethicone improves visibility in upper GI tract endoscopy. We examined three-hundred-thirty patients referred for upper endoscopy who were randomized and were required to swallow a placebo solution or one of three liquid simethicone solutions 15 min prior to the examination. These solutions contained 65 mg, 65 mg and 195 mg of drug dissolved in 90 ml, 30 ml and 90 ml of water, respectively. Patients treated with both dosages of simethicone revealed significantly less foam and bubbles in both the stomach and the duodenum compared to placebo. Only the 90 ml volume adequately cleared both locations. The reduction of examination time could be found both in patients with an intact stomach and in patients with or without gastric bile reflux, but was most striking in patients with previous gastric resection (examination time being reduced by almost 50% and the need of adjunctive lavage being reduced about 20 fold compared to placebo). In conclusion, pre-procedural oral simethicone should be routinely considered in patients with previous gastric resection. The utility of the drug is less evident in patients with normal gastric anatomy.

Double-Blind Method↗
PubMed1991

Inhibition of Epstein-Barr virus production in P3HR-1 cells by Epstein-Barr virus-seropositive human serum.

The effect of human serum with or without Epstein-Barr virus (EBV) antibodies was characterized on virus production in P3HR-1 cells. Cell culturing with EBV-seropositive sera reduced both production of infectious virus and amounts of virion DNA in the supernatants. EBV DNA was also reduced in the cells. Such reductions in cell-associated EBV DNA depended upon the concentration of seropositive serum and incubation time. Decreased frequencies of productive EBV DNA-replicating cells were observed in cell populations which had reduced levels of cell-associated EBV DNA. The inhibitory effect of seropositive serum was reversed upon switching the cells to medium with seronegative serum. In serial sera of an acute infectious mononucleosis patient the EBV DNA-reducing activity arose in parallel to antibodies against EBV membrane antigen and nuclear antigen. Possible mechanisms were discussed for antibody-mediated inhibition of EBV production.

Antibodies, Viral↗
PubMed1990

Genetic analysis of chromosomal operons involved in degradation of aromatic hydrocarbons in Pseudomonas putida TMB.

The catabolic pathway for the degradation of aromatic hydrocarbons encoded by Pseudomonas putida TMB differs from the TOL plasmid-encoded pathway as far as regulation of the upper pathway is concerned. We found, by analyzing Tn5-induced mutants and by Southern blot hybridization with appropriate probes derived from the TOL plasmid pWW0, that the catabolic genes of strain TMB were located on the bacterial chromosome and not on the 84-kb plasmid harbored by this strain. The catabolic genes of TMB and pWW0 had sequence homology, as shown by Southern blot hybridization, but differed significantly in their restriction patterns. The analysis of the mutants suggests that a regulatory mechanism similar to that present in pWW0 coexists in TMB with a second mode of regulation which is epistatic on the former and that the chromosomal region carrying the catabolic genes is prone to rearrangements and deletions.

Chromosome Mapping↗
PubMed1990

Synthetic peptides to identify antigenic determinants on Epstein-Barr virus gp350/220.

We synthesized three peptides, MA1 - Thr19-Val28(+Tyr) -, MA2 - Ser807-Ala816-, and MA3-Ser718-Glu729(+Tyr) from the sequence of Epstein-Barr virus gp350/220 and immunized rabbits with these peptides. Rabbit antisera to the peptides had antipeptide radioimmunoassay titers of 1:400 for anti-MA1, 1:200 for anti-MA2, and 1:1600 for anti-MA3. The anti-MA1 serum recognized gp350/220 in Western blotting to SDS-electrophoresed proteins from 12-O-tetradecanoylphorbol-13-acetate- and n-butyrate-treated B95-8 cells, but anti-MA2 and MA3 sera did not. None of the sera reacted with gp350/220 by membrane or cytoplasmic immunofluorescence or by immunoprecipitation of Triton X-100 solubilized proteins.

Animals↗
PubMed1989

Isolation and characterization of an ipt gene from the Ti plasmid Bo542.

A 1.9 kb clone of the T-DNA region of the Agrobacterium tumefaciens Ti plasmid Bo542 which exhibited homology to the isopentenyl transferase (ipt) locus of pTiA6 was identified by low stringency DNA hybridization. Introduction of this segment of pTiBo542 DNA into cells of Nicotiana tabacum or N. glauca caused tumor formation in vivo, and allowed hormone independent growth in vitro. Furthermore, this DNA segment complemented ipt mutant strains of A. tumefaciens, restoring their ability to cause tumors on Kalanchöe leaves and tomato stems. The complete DNA sequence of this segment has been determined, revealing an open reading frame homologous to other known Agrobacterium ipt genes.

Alkyl and Aryl Transferases↗
PubMed1989

Intracellular synthesis of Epstein-Barr virus membrane antigen gp350/220. Inhibitory effect of monensin on its expression.

We have defined the intracellular expression and localization of gp350/220, one of the Epstein-Barr virus (EBV) induced membrane antigens, on 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and n-butyrate-treated P3HR-1 cells. 1B6 monoclonal antibody (mAb) immunoprecipitated gp350/220 from [35S]-methionine-labeled cells, as confirmed with other mAbs (2L10, 72A1, and C1), to the same membrane antigen. The appearance of gp350/220 was observed about 14 h after TPA and n-butyrate activation and reached a maximal level at about 48 h. 1B6 mAb membrane immunofluorescence-positive and cytoplasmic fluorescence-positive cells appeared progressively in cell populations at the same frequencies. Cytoplasmic immunofluorescent staining with 1B6 mAb demonstrated a paranuclear complex which was identical to a rhodamine-labeled wheat germ agglutinin-stained pattern which has been ascribed to the Golgi apparatus. We investigated the effect of monensin on gp350/220 expression and processing. Monensin at 10(-7) M significantly inhibited membrane antigen expression in the Golgi apparatus and on the cell surface, but had a negligible effect on synthesis of viral capsid antigen, early antigen, and viral DNA. The inhibition of gp350/220 with monensin was further characterized by the immunoprecipitation of gp350/220 with anti-MA-positive human sera and mAbs. Monensin treatment resulted in the accumulation of a 165-kD molecule which was judged to be a precursor of gp350/220. These results were consistent with the view that the Golgi apparatus plays an important role as a place of synthesis, processing, and maturation of gp350/220.

Antigens, Viral↗
PubMed1989

Hereditary adenomatosis of the colon and rectum: clinical features of eight families from northern Italy.

Adenomatosis coli (or familial polyposis of the large bowel) and related syndromes are relatively rare diseases characterized by an autosomal dominant mode of inheritance. In these diseases, the entire colorectal mucosa is covered by hundreds (often innumerable) polyps of various dimensions. In addition, several extracolonic abnormalities have been reported. In the present study, we describe the clinical features of eight families from northern Italy fulfilling the diagnostic criteria of adenomatosis coli. Information was available on 123 unaffected and 30 affected family members. The most relevant findings of the study can be summarized as follows. 1) Gene frequency was calculated to be between 1:7,300 and 1:19,000. Segregation ratio in affected branches was 0.57, with a gene penetrance of nearly 60% and a male:female ratio of 1.73. 2) Extracolonic manifestations were present in all families and in 15 of 30 affected patients, the most frequent being cutaneous cysts and retinal lesions. No case fulfilling the classical criteria of Gardner syndrome was observed. 3) When the diagnosis of adenomatosis followed the appearance of symptoms, colorectal cancer had usually already developed, whereas no malignant changes were observed in individuals diagnosed in the asymptomatic stage. When colectomy with ileorectal anastomosis was the treatment of choice, polyps tended to recur in the rectal stump, and long-term endoscopic follow-up was necessary. In conclusion, adenomatosis coli may account for a definite proportion of colorectal neoplasms observed in the general population. Taking into consideration the genetic base of the disease, it follows that individuals at risk should be closely monitored for several years. Moreover, clinical investigations should not be limited to the large bowel, but should be extended to the skin, upper digestive tract, fundus oculi, bones, and probably other organs.

Adenomatous Polyposis Coli↗
PubMed1988

Unimpaired membrane dynamics in parathyroid cells in insulin deficient rats.

The responsiveness of parathyroid cells in insulin deficient and short-term diabetic rats was investigated by morphometric analysis. Insulin deficiency was produced by intravenous injection of D-mannoheptulose and short-term (7 days) diabetes mellitus by intraperitoneal application of streptozotocin. Parathyroid glands were stimulated for parathyroid hormone secretion by decreasing the serum calcium concentration through intravenous infusion of EGTA. Parathyroid cells of controls, insulin deficient, and short-term diabetic rats responded to reduced serum calcium by a 45% increase of the cell surface area. This increase is assumed to be the result of the membrane-bound transport of parathyroid hormone from the Golgi complex and secretory granules to the plasma membrane and subsequent exocytic release of parathyroid hormone induced by the low serum calcium concentration. Therefore, the unimpaired increase in the cell surface area of parathyroid cells in insulin deficient and short-term diabetic rats indicates that insulin does not modulate the release of parathyroid hormone. It is also considered likely that synthesis of parathyroid hormone is not suppressed in short-term diabetes but that fat metabolism is disturbed leading to accumulation of lipid vacuoles.

Animals↗
PubMed1988

Inhibition of Epstein-Barr virus (EBV) release from P3HR-1 and B95-8 cell lines by monoclonal antibodies to EBV membrane antigen gp350/220.

Antibody-mediated inhibition of Epstein-Barr virus (EBV) release from the EBV-productive cell lines P3HR-1 and B95-8 was probed with two monoclonal antibodies (MAbs), 72A1 and 2L10, which immunoprecipitated the same EBV membrane antigen (MA) gp350/220 found with the 1B6 MAb with which inhibition of EBV release from P3HR-1 cells was first described. These three MAbs were not equivalent in either MA reactivities or functional effects, reflecting the variable expression of different epitopes of gp350/220. 1B6 recognized MA on P3HR-1 cells, which expressed predominately the gp220 form of MA. 1B6 did not recognize (or barely recognized) a determinant on B95-8 cells. MAbs 2L10 and 72A1 reacted as well with B95-8 cells as they did with P3HR-1 cells. MAbs 1B6 and 2L10 neutralized neither P3HR-1 nor B95-8 virus, but 72A1 neutralized both viruses. MAbs 1B6 and 72A1 inhibited P3HR-1 virus release, as measured by the assay for infectious virus and by DNA hybridization analysis of released virus, but 2L10 had no such activity. 72A1 (but not 1B6) inhibited release of EBV from B95-8 cells. These experiments pointed to the presence of three different epitopes on gp350/220, identified with the respective MAbs and having varying involvement in virus neutralization and virus release inhibition.

Antibodies, Viral↗
PubMed1987

Nasobiliary drainage following endoscopic sphincterotomy. A useful method of preventing and treating early complications.

The authors analyze a retrospective study of 850 patients who underwent endoscopic sphincterotomy (ES). One group of patients (705) routinely had nasobiliary drainage following ES as a prophylactic measure to prevent complications, while 145 patients were not drained. Complications, mortality and the need for emergency surgery were compared in both groups. In the drained group, the complication rate was 2% vs 10.3% in the nondrained group (P less than 0.001), and mortality was 0.4% vs 2.7% (P = 0.03). Emergency surgery was required in 0.1% in the drained patients versus 3.4% in the nondrained group (P = 0.01). Based on these data within the limits of a retrospective study, the authors strongly support the routine use of nasobiliary drainage to prevent complications, which usually occur within the first 24 h, and also to facilitate the immediate treatment of the complications. This procedure is also highly recommended when ES is performed by inexperienced endoscopists and with a technically demanding ES, which is frequently followed by complications.

Bile↗
PubMed1986

Foreign bodies of the biliary tract. Endoscopic management.

In the period 1978-1984, 23 patients underwent endoscopic intervention for foreign bodies of the biliary tract. The patients are subdivided into three groups: the first group consists of 11 cases in which the foreign bodies were suture threads, either simple or as a nidus for gallstones; the second group consists of six patients with a sump syndrome of the biliary tract; the third group includes six patients who retained drainage tubes or stents after a biliary tract operation. In our series, endoscopic extraction was performed as a first-choice procedure. The high success rate may favor endoscopy as a low-morbidity, low-mortality approach and as an alternative to a relaparotomy.

Biliary Tract↗
PubMed1986

Colonoscopic excision of large and giant colorectal polyps. Technical implications and results over eight years.

Large polyps are sessile or pedunculated lesions that are larger than or equal to 3 cm in size. Sixty-six colonoscopic piecemeal excisions of large pedunculated and sessile polyps (75 percent of 88 recognized large polyps) were performed over eight years. The macroscopic feature of the lesions and the result of an extensive snare biopsy were the deciding factors for endoscopic as opposed to surgical removal. Only three complications (4.5 percent) were recorded (two hemorrhages and one colonic wall burn syndrome), none of which required surgery. Fifty patients with 52 adenomatous lesions had colonoscopic follow-up (range, 3 to 85 months). Of 36 sessile adenomas, two cases of residual (5.5 percent) and four of recurrent disease (11 percent) were observed. Colonoscopic removal is an alternative to local surgical excision of large benign colorectal polyps, and often can be an alternative method to elective colectomy in elderly and high-risk patients.

Adenocarcinoma↗