Search PubMed⌕ Search

Biomedical subjects

G Valenti

Publications and source records attributed to G Valenti.

At least 109 records · Page 6Linked to original sources
PubMed1991

Comparative efficacy of ceftriaxone versus ceftazidime in the treatment of nosocomial lower respiratory tract infections.

Seventy-two hospitalized patients with pneumonia or bacteremia were randomly allocated to receive ceftriaxone 2 g once daily i.v. or ceftazidime 2 g twice a day i.v. At the end of the study 60 patients were evaluable, 31 in the ceftazidime group and 29 in the ceftriaxone group. Thirty-four patients (ceftazidime = 15, ceftriaxone = 19) yielded one or more pathogens, of which 64% were gram-negative bacilli. Clinical cure or improvement was observed in 90% of patients in both groups. All 3 cases of bacteremia were cured. Three patients in each group failed to respond to the administered drug. Eradication of the pathogen(s) was observed in 82% of the ceftazidime group and in 86% of the ceftriaxone group. Two episodes of superinfection due to Pseudomonas aeruginosa were recorded in the ceftriaxone group, while Candida spp. was isolated from the sputum in 2 patients in the ceftazidime group. Three strains of P. aeruginosa (2 in the ceftazidime group, 1 in the ceftriaxone group) persisted despite the treatment. No side effects were seen except for skin rash in 2 patients receiving ceftazidime. Compliance was good in both groups, particularly with the once daily administration of ceftriaxone. Overall ceftriaxone and ceftazidime appear to be equally effective in the treatment of nosocomial pneumonia, with the exception of P. aeruginosa infection.

Adolescent↗
PubMed1991

Effects of cytidine 5'-diphosphocholine administration on basal and growth hormone-releasing hormone-induced growth hormone secretion in elderly subjects.

The basal and GH-releasing hormone-stimulated secretion of GH declines in the elderly. We tested the ability of cytidine 5'-diphosphocholine, a drug used in the treatment of stroke and Parkinson's disease, to alter GH secretion in 11 healthy elderly volunteers, aged 69-84. Each subject received an iv infusion of 2 g of cytidine 5'-diphosphocholine or normal saline. GHRH and TRH were also administered during cytidine 5'-diphosphocholine infusions. The infusion of cytidine 5'-diphosphocholine induced a 4-fold (p less than 0.05) increase in serum GH levels over basal values. A small increase in GH was seen after GHRH administration. However, the addition of GHRH to the cytidine 5'-diphosphocholine infusion resulted in a GH response which was significantly greater than that seen after GHRH alone; the integrated concentration of GH was more than 2-fold greater in the cytidine 5'-diphosphocholine treated group (706.85 +/- 185.1 vs 248.9 +/- 61.4 micrograms.l-1.(120 min)-1; p = 0.01). The PRL and TSH responses to TRH were not significantly affected by cytidine 5'-diphosphocholine infusion, indicating that dopaminergic mechanisms are not involved. These studies demonstrate that cytidine 5'-diphosphocholine can enhance basal and GHRH-stimulated GH release in the elderly, but the mechanism of action of the drug remains unclear.

Aged↗
PubMed1991

Evaluation of mucinous-like cancer antigen (MCA) in women with breast disease: preliminary results.

Mucinous-like cancer antigen (MCA) is a substance which is recognized by a novel monoclonal antibody, designated b12, when directed against a mixture of human breast cancer cell lines. The present study was carried out by means of a solid phase enzyme immuno assay to determine, prior to treatment, circulating levels of MCA in 131 women with malignant and in 99 with benign breast diseases (BBD). Statistical analysis did not reveal any significant difference between MCA values in healthy controls vs. BBD patients. By contrast, MCA levels were significantly higher in cancer patients as compared to the other groups (p less than 0.001). In particular, patients with metastatic disease had the highest MCA concentrations. The sensitivity and specificity of the test were 25.5 and 97.5%, respectively. The characteristics of MCA (low sensitivity, high specificity) encourage its evaluation as an indicator of tumor burden.

Adolescent↗
PubMed1991

Antidiuretic response: what markers for water channel components?

Antidiuretic hormone increases the water permeability of its target epithelial tissues by triggering the insertion into the apical cell membrane of aggregated intramembrane particles that contain channels specific for water. Little is known about the chemical composition of these membrane particles and of the water channel components. Present work describes a procedure for obtaining selected antibodies that specifically recognize ADH-induced components of the apical membrane in the amphibian urinary bladder epithelial cells.

Animals↗
PubMed1991

Identification of breast cyst subpopulations: biochemical and morphological features.

The concentration of insulin-like growth factor-I (IGF-I) and its relationship to other biochemical parameters of cyst fluids was investigated in 94 cyst fluids of 86 women with gross cystic breast disease. The relationship between the biochemical parameters and the cytological features of breast fluids (presence or absence of apocrine cells) was also studied. IGF-I was detected in all tested fluids, with a concentration 50 to 100 times lower than that found in plasma. IGF-I concentration was higher in cysts with a Na+/K+ ratio greater than 3 (greater than 3) and was inversely related to both dehydroepiandrosterone sulfate (DHEA-S) and epidermal growth factor (EGF) concentration (p less than 0.001). It is suggested that Na+/K+ greater than 3 cysts have a higher permeability to plasma and extracellular fluids compared to Na+/K+ less than 3 cysts. Apocrine cells were found in 78% of Na+/K+ less than 3 fluids as well as in 53% of Na+/K+ greater than 3 fluids. A well-defined relationship was found between the biochemical parameters of breast fluids, but the presence of either IGF-I or EGF was not related to the morphology of breast cysts as assessed by cytological examination.

Biopsy, Needle↗
PubMed1991

Fibrosclerotic lymphedema: pathophysiology and therapy.

We describe our experience with 12 patients with severe fibrotic lymphedema treated between 1979 and 1987. Each patient initially underwent nonoperative treatment (postural drainage and pneumatic compression) and in 10 patients who required operation, these measures were continued postoperatively. Operation included excision of subcutaneous tissue (debulking), which was extensive in 8 and limited in 2 patients. Only 2 patients were satisfactorily managed by nonoperative treatment alone. Based on the extensive pathophysiologic changes that occur in the tissue microenvironment with lymph stasis, it is unlikely that at this advanced stage of lymphedema that nonoperative treatment alone or "physiologic" operations such as lymphatic-venous shunt or lymphatic collector reconstruction is satisfactory. Rather, nearly all such patients require limited or extensive excision of the fibrotic-edematous subcutaneous tissue.

Connective Tissue↗
PubMed1990

Dissociated effect of buserelin on luteinizing hormone (LH) and alpha subunit in men.

Chronic treatment with LHRH analogs is known to depress testosterone (T) values to castration levels. In contrast to results from animal experiments, studies in humans indicate that a pituitary-dependent mechanism predominates in the suppression of plasma T. However, this reduction in T levels may occur when LH values are within or below the normal range. One explanation for this result has been that while absolute values of LH in serum may not change, the bioactivity of LH is reduced. The present study has been performed to determine whether this discrepancy between LH and T values is obscured by the hypersecretion of the alpha-subunit which is devoid of any biological activity but crossreacts in most RIAs with LH. Following 2 days of blood collection to establish basal serum hormone levels, six men with prostatic cancer were treated with the LHRH agonist, Buserelin (500 micrograms sc, daily injection) for 15 days. The most significant endocrine responses at the end of this treatment were as follows: 1) T levels were depressed to the castration range; 2) no change was seen in the LH values with a conventional RIA procedure which crossreacted with the alpha-subunit; 3) a significant decrease was found in the LH values evaluated with an immunoradiometric (IRMA) method, which shows no cross-reactivity with the alpha-subunit; 4) there was a significant increase in the alpha-subunit levels; and 5) serum FSH levels were significantly decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Secretion of alpha-subunit and intact gonadotropins after surgical and chemical castration.

In order to investigate the regulatory mechanisms involved in the secretion of glycoprotein hormones, we studied the secretory patterns of LH, FSH and alpha-subunit in hypogonadal men. Three groups of patients with carcinoma of the prostate were studied both before and 15 days after orchiectomy, or the initiation of ketoconazole or LHRH analog therapy. There were significant increases (P less than 0.01) in LH and alpha-subunit levels in the patients treated with orchiectomy and ketoconazole, but FSH levels increased only in the orchiectomized patients. After LHRH analog treatment, LH levels were significantly decreased when assayed with an immunoradiometric assay method which does not cross-react with alpha-subunit. FSH values were significantly lower than pretreatment levels, while alpha-subunit levels remained significantly elevated throughout the study period. These results demonstrate that after both chemical (ketoconazole) and surgical castration, the secretion of alpha subunit follows a pattern which is tightly correlated with that of LH but not of FSH. However, after LHRH analog treatment, alpha-subunit appears to be the sole secretory product of the gonadotroph.

Aged↗
PubMed1990

Effects of calcifediol treatment on the progression of renal osteodystrophy during continuous ambulatory peritoneal dialysis.

Mineral metabolism was studied in 31 patients with chronic renal failure on continuous ambulatory peritoneal dialysis (CAPD) for a year. After baseline observations, 1-year calcifediol treatment was started in all the patients (100 micrograms/day). After therapy, progressive normalization of calcium levels was found in all the patients, while plasma phosphate did not change. After therapy, plasma alkaline phosphatase and parathyroid hormone decreased significantly. 1,25-Dihydroxyvitamin D showed a slight increase, and 25-hydroxyvitamin D (extremely low at the start of the study) rose, reaching normal levels, after 1 year of treatment. Bone mineral density and bone biopsy indexes showed general improvement after calcifediol. In conclusion, calcifediol seems to act positively on the disorders of mineral metabolism in CAPD.

Alkaline Phosphatase↗
PubMed1990

Kinetics of anti-Xa activity during combined defibrotide-heparin administration in hemodialysis.

Defibrotide, a polydesoxyribonucleotide derivative with antithrombotic and fibrinolytic activity, capable of inducing the release of PGI2 from vascular endothelia, was proposed as an alternative to standard heparin coverage during blood dialysis for patients at risk of bleeding. The original procedure featured the preliminary washing of the dialysis circuit with heparin, which was then recirculated and eliminated, and the two drugs, heparin and defibrotide, are known to interact with each other. The purpose of this present study was to explore the ex-vivo heparin activity (assessed as anti-Xa activity) in diverse hemodialysis models using defibrotide (800 mg intravenous, in 4 bolus injections) and various dosages of heparin. Anti-Xa activity is negligible in dialysis conducted with defibrotide alone. When the circuit was prewashed with heparin (5000 and 2500 IU), there was evident anti-Xa activity (0.3-0.5 U/ml) in the first 30-60 minutes of dialysis; continuous heparin infusion (500 U/hour) resulted in high anti-Xa activity levels at the end of dialysis. Thus the best hemodialysis procedure for patients at high risk of bleeding should be one utilizing only defibrotide, or defibrotide plus small amounts of calcium heparin infused at the rate of 500 U/hour for not more than two hours.

Drug Interactions↗
PubMed1989

Calcitonin inhibition of growth hormone-releasing hormone-induced GH secretion in normal men.

Calcitonin has been shown to modulate pituitary hormone secretion in a variety of ways. In this study we examined the effects of a salmon calcitonin infusion on GHRH-induced GH secretion in 5 normal men. In addition, in vitro experiments were performed using primary cultures of rat anterior pituitary cells in order to examine whether there is a direct pituitary effect of CT. Infusion of CT significantly blunted the GH response to GHRH in all subjects without affecting basal GH secretion or plasma calcium levels. Infusion of CT was accompanied by significant increases in ACTH, beta-endorphin, cortisol and free fatty acid levels, and by a significant decrease in serum insulin levels. The addition of CT to primary cultures of rat pituitary cells did not alter basal or stimulated secretion of GH or ACTH. These results indicate that: 1) CT blunts the GH response to GHRH; 2) CT infusion results in the stimulation of the hypothalamic-pituitary-adrenal axis, and 3) this effect is probably exerted at the hypothalamic level, since no direct activity of CT was documented in vitro on either GH or ACTH secretion.

Adrenocorticotropic Hormone↗
PubMed1989

Fluorescence labeling of proteins related to ADH-induced change in frog bladder luminal membrane.

Sulfhydryl (SH) reactive reagents, such as eosin derivatives, have been found to be useful in labeling water pathways in red cells. In the present study we used an impermeable SH-reagent, a fluorescent maleimide analogue EMA (eosin-5'-maleimide), in order to identify proteins involved in water permeability response to antidiuretic hormone (ADH). We observed that: 1) EMA (1 mM) mucosal pretreatment did not modify either the basal water flux or the subsequent ADH-induced hydrosmotic response; 2) EMA added to the mucosal bath at the maximum response to ADH, significantly decreased net water flux by about 40%; similar results were obtained when 10(-5) M forskolin was used as a hydrosmotic agent. These results suggest that the inhibitory effect of EMA occurs at a post cAMP step, possibly at the level of the sulfhydryl groups of the water channels themselves. Fluorescence distribution in SDS-PAGE of Triton X-100 extracted proteins from bladder labeled with EMA in both control conditions and under ADH stimulation allowed us to identify apical membrane proteins, labeled during ADH stimulation and not labeled in water impermeable controls. Of particular importance are four proteins of 52, 32-35, 26, 17, kDa. These polypeptides are probably involved in ADH-stimulated water transport and may be components of the water channels.

Animals↗
PubMed1989

[Role of the ultrasonic examination in the diagnosis of pelvic pathology].

The diagnostic accuracy of sonography in pelvic pathology is assessed in the case in which the operator is aware of the clinical report. Results attribute in absolute terms more effectiveness to sonography than to the clinical examination but it must, in any case, be considered as an extension of the gynaecological examination and not a replacement of the anamnestic history and physical examination.

Diagnostic Errors↗
PubMed1989

Microtubules and actin microfilaments in the amphibian bladder granular cells.

Microtubules and microfilaments were localized by an immunocytochemical method in the granular cells of the frog bladder after fixation and isolation. An extensive array of microtubules was observed in the granular cells with an orientation towards the luminal plasma membrane in the supranuclear zone. Actin filaments formed a continuous bundle that underlined the cellular membrane. After incubation in the presence of colchicine, nocodazole, or tubulozole, the microtubular network appeared fragmented but did not disappear completely. These observations are related to the role of the cytoskeleton in the permeability response of the frog bladder epithelium to vasopressin.

Actin Cytoskeleton↗