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Biomedical subjects

L Barbieri

Publications and source records attributed to L Barbieri.

At least 73 records · Page 4Linked to original sources
PubMed1992

Inhibition of protein synthesis in liver and kidney of mice by bolesatine: mechanistic approaches to the mode of action at the molecular level.

Protein synthesis was assayed in liver and kidney of mice treated with bolesatine, a toxic glycoprotein from the mushroom Boletus satanas (Lenz) which was previously shown to be an inhibitor of protein synthesis by cell-free systems in vitro and by cultured cell-lines. Protein synthesis in vivo (Swiss mice) is inhibited in a dose-dependent manner in liver and kidney. The mechanism of action does not appear to be due to RNA-N-glycosidase activity of bolesatine or a RNAase activity of this toxin on the ribosomal RNAs. Ribosomes do not appear to be damaged by pretreatment with bolesatine as judged by a poly(U) translation system. Thus bolesatine cannot be included in the group of protein synthesis inhibitors of plant origin known as ribosome-inactivating proteins (RIPs).

Animals↗
PubMed1992

Transrectal microwave hyperthermia for benign prostatic hyperplasia: long-term clinical, pathological and ultrastructural patterns.

Transrectal microwave hyperthermia of the prostate was administered to 191 patients with bladder outlet obstruction due to benign prostatic hyperplasia who were either at poor operative risk or who refused surgery. Patients were divided in 2 groups according to age and they underwent either 5 or 10, 60-minute sessions of hyperthermia, with a calculated intraprostatic temperature of 42.5 plus or minus 0.5C. Light and electron microscopy showed no irreversible damage at the glandular epithelium but did demonstrate a significant increase in neoformed intraprostatic capillary-like vessels. At 1, 12 and 24 months residual urine volume was significantly decreased in the majority of patients but only a minor amelioration of urinary flow rates and subjective symptoms was observed. According to maximum flow nomograms all patients were still obstructed postoperatively. Transrectal hyperthermia cannot be considered a genuine alternative to surgery for patients with bladder outlet obstruction due to benign prostatic hyperplasia.

Aged↗
PubMed1992

Ribosome-inactivating proteins from plants: present status and future prospects.

Plant ribosome-inactivating proteins (RIPs) are N-glycosidases which cleave the N-glycosidic bond of adenine in a specific ribosomal RNA sequence. Most commonly RIPs are single-chain proteins (type 1 RIPs), but some (type 2 RIPs) possess a galactose-specific lectin domain that binds to cell surfaces. The latter RIPs are potent toxins, the best known of which is ricin. RIPs have antiviral and abortifacient activities, and, in a widespread application, can also be linked to antibodies or ligands to form immunotoxins or conjugates specifically toxic to a given type of cell.

Adenine↗
PubMed1992

[Digital radiology with storage phosphors in cephalometric study in orthodontics].

Conventional radiology is continually modified with the development of digital systems which can be used for several types of radiologic examinations. Our study was aimed at evaluating the advantages of these new technologies in the orthodontic field, where the problems associated with image quality and radiation protection are major especially in young patients; the latter goal is achievable by dramatically reducing radiation dose and by avoiding repeating the exam. In our study, we compared lateral teleradiographs of the skull for cephalometric analysis obtained using conventional and digital diagnostic methods. The preliminary results demonstrated that the two imaging techniques did not differ relative to bone structure representation, even though the digital system provided better visualization of soft tissue structures. Computed radiography also allowed a marked reduction in the number of repeats and reduced radiation dose. The current disadvantages of this imaging method are the high initial cost of the equipment, reduced work rate, and the need of frequent technical assistance.

Adolescent↗
PubMed1992

[Coronary angioplasty in the aged: short and long term efficacy in patients with unstable angina].

Coronary revascularization procedures in elderly patients are associated with an increase of perioperative complications and death in comparison with younger patients. To assess if a conservative coronary angioplasty approach is useful, 54 consecutive patients (pts) with severe unstable angina were retrospectively evaluated. Mean age was 73 years (range 70-82 years). Multivessel coronary disease was present in 26 pts (48%), angina at rest within the last 2 days in 26 (48%) and an episode of myocardial infarction within 2 weeks in 21 (38%). In 51 cases, regardless of the extension of the coronary disease, only the stenosis considered "culprit" of the symptoms, as assessed by angiography and by noninvasive studies, was dilated. The angiographic success rate was 98% (53 of 54 pts). Two pts had procedure--related myocardial infarction. One patient died after emergency bypass surgery for an abrupt left anterior descending artery occlusion. The mean hospital stay was 8 days (range 2-40 days) and in 75% cases was less than 6 days. Follow-up (achieved in 51 pts) ranged from 1 to 40 months (mean 20 months). In 3 pts a second vessel was treated with a new angioplasty 15-30 days after the first procedure due to the persistence of symptoms. During follow-up three pts died (1 death was cardiac). Of the survivors, 35 were asymptomatic in moderate medical regimen, 1 required bypass surgery and 3 were managed with repeat angioplasty. Survival was 95% at 6 months and 90% at 2 years. At six months 86% of pts were event free (80% and 70% at one and two years, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

A cortical lectin from the oocytes of Rutilus rutilus stimulates mitogenic activity and release of soluble factors from human lymphocyte cultures and inhibits protein synthesis in a cell-free system.

1. A cortical granule lectin was isolated from vitellogenic oocytes of a bony fish, the roach Rutilus rutilus. 2. The lectin agglutinates human erythrocytes, is specific for L-rhamnose and is composed of different polypeptide subunits. 3. The lectin is the first lectin of animal origin that inhibits protein-synthesis by a rabbit reticulocyte lysate, and is also mitogenic for human lymphocytes.

Adult↗
PubMed1991

Effects of plant ribosome-inactivating proteins on ribosomes from Musca domestica.

1. Ribosomes from M. domestica larvae were isolated and their susceptibility to the action of several ribosome-inactivating proteins (RIPs) from plants was tested. 2. Ribosome-inactivating proteins inhibited, to different extents, phenylalanine polymerization by ribosomes. 3. Analysis of RNA from RIP-treated ribosomes showed the appearance of an aniline-cleavable rRNA fragment resulting from the N-glycosidase activity of the RIPs. 4. The release of adenine from saporin 6-treated M. domestica ribosomes was demonstrated by h.p.l.c. analysis.

Adenine↗
PubMed1991

[Double-contrast enema. Study of the mucosal pattern and the organ profile with conventional and digital methods].

A solid state digital system (FCR 101) was employed in our comparative evaluation of the image quality of conventional versus digital techniques in the study of colon by means of double-contrast enema. Sixty patients were examined with a single AP view, using digital radiography with 100% radiation dose and progressive 50% and 75% reductions; the radiographs thus obtained were then compared with the corresponding conventional ones. The examined parameters were organ profile and mucosal pattern. Each digital and conventional radiograph was evaluated by 2 independent radiologists and a value was given to each parameter i.e., 1 = good, 2 = sufficient, 3 = insufficient. Upon comparison of the average values obtained for digital and conventional radiographs in optimal conditions and with a dose reduced by 50%, the digital technique was seen to give a more detailed and accurate representation of both low-contrast mucosal pattern and of organ profile. With the dose reduced by 75%, a slight increase was observed in background noise which caused a slight loss in image definition, but this did not reduce image readability with respect to conventional radiographs. To conclude, the digital method with a 50% exposure reduction is to be preferred in the examination of the colon, especially in pediatric radiology; furthermore, since this technique allows better detailing at lower contrast, it is to be preferred in the study of the pathologic conditions affecting mainly/only the mucosal pattern--e.g., cancer, ulcerative colitis, Crohn's disease, and so on. An exposure dose reduced by 75% may be used for following lesions previously diagnosed and when a less detailed depiction of the mucosal pattern is enough.

Adult↗
PubMed1990

Purification and properties of new ribosome-inactivating proteins with RNA N-glycosidase activity.

Ribosome-inactivating proteins (RIPs) similar to those already known (Stirpe & Barbieri (1986) FEBS Lett. 195, 1-8) were purified from the seeds of Asparagus officinalis (two proteins, asparin 1 and 2), of Citrullus colocynthis (two proteins, colocin 1 and 2), of Lychnis chalcedonica (lychnin) and of Manihot palmata (mapalmin), from the roots of Phytolacca americana (pokeweed antiviral protein from roots, PAP-R) and from the leaves of Bryonia dioica (bryodin-L). The two latter proteins can be considered as isoforms, respectively, of previously purified PAP, from the leaves of P. americana, and of bryodin-R, from the roots of B. dioica. All proteins have an Mr at approx, 30,000, and an alkaline isoelectric point. Bryodin-L, colocins, lychnin and mapalmin are glycoproteins. All RIPs inhibit protein synthesis by a rabbit reticulocyte lysate and phenylalanine polymerization by isolated ribosomes and alter rRNA in a similar manner as the A-chain of ricin and related toxins (Endo et al. (1987) J. Biol. Chem. 262, 5908-5912).

Amino Acid Sequence↗
PubMed1990

Toxicity of, and histological lesions caused by, ribosome-inactivating proteins, their IgG-conjugates, and their homopolymers.

The toxicity of, and the lesions brought about by, several ribosome-inactivating proteins (bryodin, gelonin, momordin, pokeweed antiviral protein from seeds, saporin 6, trichokirin and momorcochin-S), either native, or conjugated to bovine IgG, or polymerized, were studied in the mouse. Severe necrotic liver damage was the main lesion present in animals receiving lethal doses of the proteins. The toxicity of ribosome-inactivating proteins increased after conjugation to IgG or homopolymerization. The toxicity of conjugates to mouse was not predictable from the inhibitory activity on cell-free protein synthesis.

Animals↗
PubMed1990

Blood clearance and organ distribution and tissue concentration of native, homopolymerized and IgG-conjugated ribosome-inactivating proteins.

1. The blood clearance, organ distribution and tissue concentration of several native, homopolymerized, and IgG-conjugated 125I-labelled ribosome-inactivating proteins (RIPs) were determined in mice. 2. Native RIPs were cleared rapidly from blood, with half-lives of 4-8 min, and were concentrated mainly in the kidneys. 3. After conjugation to IgG the three RIPs studied showed increased blood half-lives and decreased concentrations in the kidneys. 4. The two homopolymers studied had blood half-lives and kidney concentrations intermediate to those of free and conjugated RIPs. 5. These results indicate that after IgG-conjugation the increased half-lives of the RIPs studied were at least in part due to the larger molecular size of the conjugates and to their lower renal excretion.

Animals↗
PubMed1989

Purification and properties of a new ribosome-inactivating protein with RNA N-glycosidase activity suitable for immunotoxin preparation from the seeds of Momordica cochinchinensis.

A ribosome-inactivating protein similar to those already known (Stirpe and Barbieri (1986) FEBS Lett. 195, 1-8) was purified from the seeds of Momordica cochinchinensis. This protein, for which the name of momorcochin-S is proposed, is a glycoprotein, has an Mr of approx. 30,000, and an alkaline isoelectric point and can be considered as an iso-form of the previously purified momorcochin from the roots of M. cochinchinensis. Momorcochin-S inhibits protein synthesis by a rabbit-reticulocyte lysate and phenylalanine polymerization by isolated ribosomes, and alters rRNA in a similar manner as the A-chain of ricin and related toxins (Endo et al. (1987) J. Biol. Chem. 262, 5908-5912). Momorcochin-S was linked to a monoclonal antibody (8A) against human plasma cells, and the resulting immunotoxin was selectively toxic to target cells.

Amino Acid Sequence↗
PubMed1989

Ribosome-inactivating proteins from plant cells in culture.

1. Ribosome-inactivating proteins were found in high amounts in one line of cells of Phytolacca americana (pokeweed) cultured in vitro and, in less quantity, in lines of Saponaria officinalis (soapwort) and of Zea mays (corn) cells. 2. The main ribosome-inactivating protein from pokeweed cells was purified to homogeneity. It is a protein with Mr 29,000 and basic pI, similar to the 'pokeweed antiviral protein' (PAP), a ribosome-inactivating protein from pokeweed leaves. We propose to call the pokeweed antiviral protein isolated from pokeweed cells PAP-C. 3. PAP-C inactivates ribosomes in a less-than-equimolar ratio, thus inhibiting protein synthesis by a rabbit reticulocyte lysate with an IC50 (concentration causing 50% inhibition) of 0.067 nM (2 ng/ml), and modifies rRNA in a manner apparently identical to that of ricin and other ribosome-inactivating proteins. It inhibits protein synthesis by intact cells with an IC50 of 0.7-3.4 microM, and is toxic to mice with an LD50 of 0.95 mg/kg.

Amino Acid Sequence↗
PubMed1989

An immunotoxin containing momordin suitable for bone marrow purging in multiple myeloma patients.

Attempts have been made by a number of methods to eliminate minimal residual disease from bone marrow to be reinfused in autologous transplantation. In this paper we describe a conjugate containing a monoclonal antibody, named 8A, recognising a plasma cell-associated antigen, and momordin, a ribosome-inactivating protein similar to the ricin A-chain. This immunotoxin is active on target cell lines and on neoplastic plasma cells, while myeloid progenitors are fairly resistant. The conjugate is shown to be acceptable for ex vivo purging in autologous bone marrow transplantation in multiple myeloma patients.

Antibodies, Monoclonal↗
PubMed1989

Selective killing of CD4+ and CD8+ cells with immunotoxins containing saporin.

Saporin, a ribosome-inactivating protein from the seeds of Saponaria officinalis, was covalently linked to an anti-CD4 monoclonal antibody. The resulting immunotoxin at 10(-9)M concentration was toxic to CD4+ lymphocytes without affecting other cells. Selective elimination of CD4+ and CD8+ cells was also obtained with murine monoclonal anti-CD4 and anti-CD8 antibodies and an immunotoxin consisting of saporin linked to an anti-mouse IgG antibody.

Antineoplastic Agents, Phytogenic↗
PubMed1989

N-terminal sequence of some ribosome-inactivating proteins.

The N-terminal portion of some type 1 ribosome-inactivating proteins (RIPs) isolated from the seeds of Gelonium multiflorum, Momordica charantia, Bryonia dioica, Saponaria officinalis and from the leaves of Saponaria officinalis are reported in the present paper. Their relationship with other RIPs is discussed.

Amino Acid Sequence↗
PubMed1989

Immunotoxins containing saporin 6 and monoclonal antibodies recognizing plasma cell-associated antigens: effects on target cells and on normal myeloid precursors (CFU-GM).

Monoclonal antibodies 8A and 62B1, recognizing plasma cell-associated antigens, were covalently linked to saporin 6, a ribosome-inactivating protein similar to the A-chain of ricin. Both immunotoxins were tested on target human cell lines U266 and Raji, on non-target K562 cell line and on myeloid CFU-GM progenitors. The cloning efficiency and viability of target cells were strongly reduced by 8A-saporin 6 and 62B1-saporin 6 immunotoxins, with an ID50 up to 200,000-fold lower than free saporin 6, whilst the K562 non-target cell line was unaffected. Normal human myeloid precursors (CFU-GM) were inhibited by immunotoxins only to a limited extent. An application of this model for autologous bone marrow transplantation in multiple myeloma patients is proposed. Since no eradication of cloning target cells was achieved by a single immunotoxin, mixtures made with different antibodies could help to reach this goal.

Animals↗