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Biomedical subjects

S Benvenuti

Publications and source records attributed to S Benvenuti.

At least 73 records · Page 4Linked to original sources

Determination of glycyrrhizin and 18 alpha-, 18 beta-glycyrrhetinic acid in rat plasma by high-performance thin-layer chromatography.

An HPTLC method is described for the simultaneous determination of glycyrrhizinic acid tripotassium salt (3K-G), 18 alpha- and 18 beta-glycyrrhetinic acid (18 alpha-GA, 18 beta-GA) in rat plasma, after oral administration of 3K-G (30 mg/kg once a day for 30 days). Systolic pressure and the volume of urine excreted in 24 hours were recorded during this period to observe any drug-induced effects.

Animals↗

Helicobacter pylori and gastric ulcer therapy: reflections and uncertainties.

The relationship between Helicobacter pylori (HP) and gastric ulcer therapy is examined by analyzing both the data that suggest that eradication of HP renders the gastric mucosa less susceptible to development of gastric ulcer as well as the substantial body of evidence that does not support this contention. The results reported in clinical trials with colloidal bismuth citrate, antimicrobial agents (furazolidone), and combinations of anti-ulcer and antimicrobial agents (H2-antagonist+cefixime, H2-antagonist+metronidazole) are reviewed. Also analyzed is the relationship between HP eradication and ulcer recurrence. Only one study is available on this aspect, and the limited evidence it provides in favour of a prophylactic effect of eradication therapy is not entirely convincing. The authors conclude that there is no reasonable case for the dogmatic assumption that eradication of HP facilitates either acute healing or long-term prophylaxis of gastric ulcer, though certain subgroups of gastric ulcer patients may benefit from eradication therapy.

Anti-Bacterial Agents↗

Effects of ipriflavone and its metabolites on a clonal osteoblastic cell line.

Protective effects of ipriflavone, an isoflavone derivative, in osteoporosis are believed to be caused by the inhibitory action on bone resorption. A direct effect of ipriflavone on bone formation is as yet unknown. Ipriflavone and four of its metabolites (I, II, III, and V) were examined for their effects on parathyroid hormone response, collagen synthesis, alkaline phosphatase activity, and cell proliferation in a clonal cell population of rat osteoblastic cells. Pretreatment of osteoblasts with high concentrations of ipriflavone for 48 h significantly inhibited the cAMP response to parathyroid hormone, producing a shift in the dose-response curve; at lower concentrations metabolites II and III potentiated the cAMP accumulation induced by low doses of parathyroid hormone. The 48 h treatment with metabolite V at the 1 nM dose significantly stimulated collagen synthesis in osteoblastic cells. Ipriflavone and metabolite I showed a biphasic stimulatory action on the alkaline phosphatase activity of osteoblasts, with a maximal effect at the 0.1 and 1 nM doses, respectively. A similar biphasic response was observed with ipriflavone and metabolite I on osteoblastic cell growth, with a maximal effect at the 0.1 nM concentration. These results suggest a direct role of ipriflavone in modulating the synthetic and growth properties of osteoblast-like cells.

Alkaline Phosphatase↗

Studies on the genotoxic properties of essential oils with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay.

Genotoxic properties of essential oils from Anthemis nobilis L., Artemisia dracunculus L., Salvia officinalis L., Salvia sclarea L., Satureja hortensis L., Satureja montana L., Thymus capitatus L., Thymus citriodorus Schreb., Thymus vulgaris L., Citrus bergamia Risso, were studied with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay. The essential oil of Artemisia dracunculus L. "Piemontese" turned out to be active in the rec-assay but not in the Salmonella test. DNA-damaging activity was demonstrated to be due to the estragol component of the oil. Advantages of the combined use of these two short-term microbial assays in genotoxic studies are discussed.

Animals↗

Antisecretory agents, peptic secretion and serum pepsinogen in man.

Less attention has been devoted to the effects of antisecretory agents on pepsin secretion than to those on gastric acid secretion, particularly in human subjects. Moreover, comparison of the various trials is far from being simple and straightforward owing to the fact that the studies available present substantial variability in terms of types of subjects (controls, DU patients), gastric secretion (basal, stimulated), type of stimulation (pentagastrin, histamine, insulin, meals, sham feeding) antisecretory drug administration route (oral, i.v.) and considered parameters (concentration, output). This review of the published data reveals that all antisecretory agents reduce pepsin output, regardless of their sometimes very different mechanism of action. Despite this, there are differences in antisecretory effects according to the agent used to stimulate gastric secretion. Even within a single drug class (H2-antagonists, prostaglandins) there may be differences depending on the potency of the compound used.

Anti-Ulcer Agents↗

[Echography in scrotal trauma].

The Authors report 28 cases of scrotal traumas evaluated during a period of 5 years on an amount of 1.100 scrotal echography: 5 patients with severe scrotal trauma are investigated with echography within 2 hours while the others between 1 and 6 days. Some cases of overlooked trauma were studied some months later. In their experience the authors underline the importance of echography in early diagnosis of scrotal contents lesions which need a surgical exploration and those which allow a medical treatment. Also ultrasound investigation is important in evaluating and in the follow-up the scrotal content lesions caused by trauma.

Biopsy, Needle↗

[Echography of injuries of the penis].

The Authors report 3 cases of penile trauma observed in a period of 6 months. The patients were studied by penile echography and cavernosography. In this series+ echotomography resulted more accurate than cavernosography which gave always negative results.

Evaluation Studies as Topic↗

[No acid, no ulcer: such a simple axiom?].

According to the traditional view gastric acid and pepsin are a sine qua non for ulcer development. Acid suppression, however, is far from being the only successful therapeutic approach, and similar healing rates are achieved by drugs with substantially different mechanisms of action--antacids, H2-antagonists, antimuscarinics, cytoprotective and site-protective agents--thus denoting a multifactorial pathogenesis. Even with the antisecretory compounds, the relationship between gastric acid and ulcer healing gives rise to perplexity: antacids prove effective at widely varying doses; pirenzipine and H2-blockers, which are clinically equieffective, differ considerably in antisecretory efficacy; H2-antagonist studies on early vs late postprandial dosing yield contradictory clinical results; morning and bedtime single administrations of H2-antagonists prove equiactive on ulcer healing, leading to a reappraisal of the alleged importance of nocturnal acidity. Ulcer sealants such as colloidal bismuth and sucralfate prove as effective as H2-antagonists despite their total lack of antisecretory activity, thereby apparently undermining the primary pathogenetic role of acid. However, with the spectacular 100% healing rates achieved by the protonpump blocker, omeprazole, the wheel has come full circle, and gastric acid appears to re-emerge as a primary element in pathogenesis. Specific therapy, based on the predominant pathogenetic factor involved, is likely to be a feasible proposition, but, at present, remains little more than a remote possibility.

Animals↗

[Plasma cell leukemia. Bibliographic review and ultrastructural study (by transmission and scanning electron microscopy) in 2 cases].

After a brief examination of the recent literature on plasma cell leukemia, the Authors describe the clinical features and the ultrastructural findings of the peripheral blood plasma cells, examined with transmission (T.E.M.) and scanning (S.E.M.) electron microscopes, of two patients with acute plasma cell leukemia. Both of them had a previous history of myeloma. T.E.M. confirmed the diagnostic value of the asynchronous plasma cells, and S.E.M. showed the characteristic microvilli and blebs, previously observed.

Aged↗

Impaired homing ability in anosmatic pigeons.

In an attempt to explain apparent differences in the pigeon homing behaviour over different regions, some experiments with anosmatic birds have been repeated on German birds. The poor initial orientation in either controls or experimentals in many single experiments and in pooled data was an insufficient basis for the evaluation of the influence of olfactory deprivation on homeward directedness. Homing success, however, was significantly worse in experimentals than in controls, which confirmed the result of impaired homing ability of anosmatic pigeons.

Animals↗

Corticosteroid-induced osteoporosis: pathogenesis and prevention.

In spite of their adverse side effects, natural and synthetic glucocorticoids (GCs) occupy a unique role in several fields of medicine. They are potent regulators of bone cell growth and differentiation and the actions on the skeleton and related tissues depend on several factors including the dose, duration of the exposure, the steroid type and the species. In humans some of the effects are indirect, such as the regulation of intestinal calcium absorption and PTH secretion. Other effects are due to the cellular response that occurs within the bone microenvironment. It has been well established in in vitro studies that GCs can promote osteoblast differentiation from mesenchymal osteoprogenitors both in rat calvarial culture and in adherent marrow stromal cells. Moreover, GCs are able to enhance expression of the mature osteoblast phenotype, increasing mineralized nodules, osteocalcin secretion, and the bone morphogenetic protein-6 message level. However, the mechanisms by which GCs affect bone metabolism are still unclear. Recent studies with GCs on bone cells suggested that the production of cytokines and growth factors and the expression of their receptors may also be influenced by GCs. In fact, GCs are able to inhibit the synthesis of cytokines, such as interleukin-1 which stimulates bone remodeling by monocytes and macrophages. Moreover, osteoprotegerin, a recently cloned member of the tumor necrosis factor receptor family, is down-regulated by GCs, offering a possible interpretation for the induction of bone resorption by GCs. GC-induced inhibition of bone resorbing cytokines may contribute to explain the therapeutic actions of GCs in several diseases such as rheumatoid arthritis and myeloma. Furthermore, GCs modulate osteoclast recruitment, even if there is no clear explanation for a direct effect of GCs on osteoclastic precursors. Sustained stimulation of matrix degradation by isolated avian osteoclasts incubated with GCs has been reported, as well as cytotoxic effects on osteoclastic cells from neonatal rat long bones.

Glucocorticoids↗