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Biomedical subjects

A Novelli

Publications and source records attributed to A Novelli.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Identification of beta-adrenoceptor subtypes in bovine ovarian and myometrial cell membranes.

Beta-adrenoceptor (beta-AR) concentrations were measured in the ovary and in the myometrium of 36 adult Friesian cows using a radiometric assay. The beta-AR content in both tissues was determined using the highly specific antagonist (-) [3H]CGP 12177 and the amounts of beta-AR subtypes were discriminated in the presence of highly selective unlabelled ligands (CGP 20712A, ICI 118 551, CGP 25827A). Scatchard analysis revealed a good linearity and Kd values suggested the existence of high affinity beta-adrenergic sites in the bovine genital tract. Total beta-AR concentrations in the ovary and in the myometrium were, respectively, 87 +/- 7 (SEM) and 240 +/- 27 fmol mg-1 of membrane protein. beta 2-AR concentrations were significantly higher (P < 0.01) in the ovary (66 +/- 5) and the myometrium (180 +/- 29) than those of beta 1-AR (21 +/- 4 and 60 +/- 5, respectively). Significant differences (P < 0.05) were also to be found between high affinity state beta 2-AR and low affinity beta 2-AR concentrations, but their values correlated negatively in the two different tissues. Natural and synthetic agonists inhibited (-) [3H]CGP 12177 binding to beta-AR in the following order of potency: (-)isoproterenol > (+/-)clenbuterol > or = (-)adrenaline >> >> (-)noradrenaline, whereas synthetic antagonists inhibited binding in the following order of potency: (-)propranolol >> (+/-)ICI 118 551 >> >> (+/-)CGP 20712A.

Animals↗
PubMedDate not supplied

Structural study of adenovirus type 2 fibre using anti-fibre and anti-peptide sera.

Peptides corresponding to the N- and C-extremities of the adenovirus 2 fibre polypeptide were synthesized, coupled to tetanus toxoid and injected into rabbits. Two sera were obtained: the anti-NTT serum and the anti-CTT serum. These sera and an anti-native-fibre serum were used to study fragments generated by hydrochloric acid cleavage of the fibre. The 44-Kd fragment corresponding to the 2/3 N-terminal part of the molecule retained its antigenic reactivity. This is consistent with a shaft structure for this part of the fibre. The anti-peptide sera were used to orientate the fibre, i.e., to determine the site of anchorage of this protein in the penton base. First, immunorevelation of blots of enzymatic digests of native or dissociated penton suggested that the N-extremity of the fibre was involved in the assembly of this protein in the penton base. Second, attempts were made to determine the accessibility of the fibre ends in the penton structure by ELISA assays and by immunorevelation of penton in Western blots. The results agreed with the proposed orientation derived from study of the enzymatic digests. Since the 2 anti-peptide sera and the peptides were unable to affect viral adsorption, it was not possible to determine how the fibre is orientated with respect to the cell receptor. However, the anti-peptide sera were found to inhibit viral production slightly.

Adenoviruses, Human↗
PubMedDate not supplied

Continuous infusion of vancomycin in methicillin-resistant staphylococcus infection.

OBJECTIVE: The aim of the study was to verify the therapeutic response of vancomycin in methicillin-resistant staphylococcus infection (MRSA/ MRCNS) administered according to two different methods (intermittent infusion vs. continuous infusion). METHOD: Experimental plan: retrospective study; study environment: university hospital, two intensive care units. Twenty-five critically ill patients submitted to antibiotic treatment with vancomycin for infection from MRSA/MRCNS were studied. The patients, who were classified according to SAPS II scores, were divided into two groups: group A (n = 14): dose of vancomycin of 0.5 g x 4/day and group B (n = 11): dose of 2 g/day of vancomycin administered in a continuous infusion. Before the antibiotic therapy was started (T1) and prior to its end (T2), the following parameters were evaluated: degree of impairment of the main organs and systems by means of sepsis-related organ failure assessment score (SOFA) and count of the white blood cells (WBC). The length of the hospital stay during intensive care was calculated for both groups (statistics: Student t test). RESULTS: No significant differences were found in the SAPS II scores and in the length of the hospital stay. In a comparison of the T1 and T2 results, we noted that patients of group A had no variations in the SOFA scores (4.84 +/- 2.48 vs. 4 +/- 3.9) and in the WBC mean values (12,415 +/- 5,099 vs. 12,841 +/- 6,864 cells/mm3). In contrast, in the patients of group B, we noted significant variations (p < 0.05) in the mean values of the SOFA scores (6.62 +/- 2.2 vs. 4.37 +/- 3.5) and in the mean values relative to the WBC count (17,242 +/- 12,842 vs. 10,757 +/- 3,610 cells/mm3). CONCLUSIONS: In critically ill patients suffering from MRSA/MRCNS infection, vancomycin administration in continuous infusions improved organ function and leukocyte response, but did not seem to modify the overall evolution of the disease.

Adult↗
PubMedDate not supplied

In vitro activity of moxifloxacin compared to other fluoroquinolones against different erythromycin-resistant phenotypes of group A beta-hemolytic streptococcus.

The aim of the present study was to evaluate the in vitro activity of moxifloxacin (BAY 12-8039) compared to ciprofloxacin, ofloxacin and sparfloxacin against 156 group A beta-hemolytic Streptococcus strains. Sixty strains were macrolide-, lincosamide- and streptogramin-B-susceptible; 16 strains exhibited a constitutive resistance phenotype; 32 strains exhibited an inducible phenotype, and 48 strains were characterized by the M-type efflux-dependent phenotype. The minimum inhibition concentrations were determined by an agar dilution method according to NCCLS-approved guidelines. Moxifloxacin showed an enhanced activity compared with the other fluoroquinolones against the different macrolide-resistant phenotypes.

Anti-Bacterial Agents↗
PubMedDate not supplied

Evaluation of tuberoinfundibular dopamine function by neuropharmacologic means in old male rats.

Baseline prolactin (PRL) levels and the PRL-lowering effect of nomifensine (Nom), an indirect dopamine (DA) agonist, were evaluated in young adult (3-5 months) and old (21 and 27 months) male rats. In addition, PRL responsiveness to acute or repeated administration of haloperidol (Hal), a DA receptor antagonist, was assessed in either young or old rats. Baseline PRL levels did not differ significantly between young and aged rats either when rats were killed by decapitation or underwent sampling from the retro-orbital venous plexus. Administration of Nom (10.0 mg/kg i.p.), a drug which inhibits PRL levels in normal rats and humans but lacks any action in conditions of impaired tuberoinfundibular DA (TIDA) function, affected PRL levels in aged rats not differently than in young rats. The PRL inhibition induced by the drug was greater in both groups when basal PRL levels were higher. Acute administration of Hal (0.5 mg/kg i.p.) increased significantly and to the same extent as PRL levels in aged and young rats. In aged rats treated chronically with Hal (0.5 mg/kg i.p., twice daily for 14 days) and sampled at the 8th day, 1 h after the first daily Hal injection, plasma PRL rose to levels about 3-fold as high as those after the first injection; in young rats, instead, the PRL-releasing effect of Hal was similar to that evoked by the first administration. 3 days after Hal withdrawal, baseline PRL levels were significantly higher in aged Hal-treated rats than in vehicle-injected or young Hal-treated rats and so were pituitary concentrations of PRL.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMedDate not supplied

Development of voltage-dependent ionic currents in rat cerebellar granule cells grown in primary culture.

In this work we studied the excitable properties of cerebellar granule cells grown in primary culture in the presence of "high" KCl (25 mM). Whole cell patch-clamp records of currents were obtained from cells at 1-33 days in culture (DIC). Sodium currents, blocked by TTX, were present from the first DIC and did show slow developmental changes. Two types of potassium currents were detected at all DIC: a delayed rectifier current (IK) and an inactivating current (IA). Both IK and IA increased until 7 to 9 DIC (four and two times respectively). Most of the IA increase, however, correlated with an increase in cell size, monitored by measurements of cell membrane capacitance (Cm) and the current density thus did not change. Conversely, delayed rectifier potassium current density did increase in the initial DIC (3-6) and did not change significantly after this time. Calcium currents were not detectable at any DIC under our experimental conditions.

Action Potentials↗
PubMedDate not supplied

[Plasma and tissue antibiotic concentrations: what is their prognostic value?].

Pharmacokinetic studies of antimicrobial agents usually involve the determination of tissue distribution, since most infections develop outside the vascular compartment. Comparative analyses of the results are often complicated by their extreme variability, depending on the various types of methods used, the type of antimicrobial agent, and the characteristics of the various tissue compartments. In general, concentrations in tissue and body fluids with no barriers to penetration of drugs are fairly predictable from blood levels in relation to simple diffusion through capillary pores. This is valid for hydrosoluble drugs such as the beta-lactams as well as liposoluble drugs like the quinolones and most of the macrolides. Thus we may derive, in a predictive sense for the clinical results, both the hematic and interstitial fluid pharmacokinetic profile of the above molecules, which are useful in relation to the MIC or MBC of extracellular pathogens. For molecules such as azithromycin, in which tropism is mainly intracellular, hematic levels do not reflect those which are therapeutic in the infection site. In tissues and body fluids with barriers to the penetration of drugs, such as the central nervous system, eye and bronchial secretions, it is always useful and especially for any new antimicrobial agent to determine the concentrations which are achieved in relation to both dosage and pathological state of the tissue compartment. The significance of the chemotherapeutic formula which gives substantial predictive value of the therapeutic efficacy at the level of blood concentrations in relation to minimal inhibitory concentration of sensitive bacteria, needs to be critically re-evaluated in light of the pharmacokinetic behavior of newer antimicrobial agents.

Anti-Bacterial Agents↗
PubMedDate not supplied

Changes in fibronectin production in rat liver during cirrhotic evolution due to treatment with CCl4 and steroid hormones: correlation with plasmatic fibronectin.

Previous our studies showed that some steroid hormones, as pure crystalline Progesterone (pPc) and 17-alpha-hydroxyprogesterone capronate (17 alpha HPC) heightened the cirrhogenic action produced in rat liver by carbon tetrachloride. Medroxyprogesterone (MPA), however, did not appear to promote cirrhosis, but increased just steatosis. In the present paper, we have studied the above mentioned steroid hormones for their possible capability of inducing changes in plasma fibronectin concentration. For this purpose, the soluble plasma fibronectin level was measured in female rats 45 days after CCl4-induced cirrhosis, and it was compared with the insoluble fibronectin of liver (detected by immunostaining) and the collagen content in the organ. The results obtained show that, after treatment with CCl4 and MPA, both plasma and liver fibronectin content strongly increases, whereas liver collagen content lowers. However, after treatment with CCl4 alone or in association with the other two steroid hormones, any changes in fibronectin content is not observable, but, on the contrary, is evident a heightened collagen production associated with a cirrhotic change of liver.

17 alpha-Hydroxyprogesterone Caproate↗
PubMedDate not supplied

[Morphologic changes in the liver of rats treated with monensin].

Monensin, a carboxylic ionophore, collapse Na+ gradient across biological membranes, increases intracellular pH and affects many processes involved in transport, posttranslational modification and secretion of proteins, moreover endocytosis and degradation in lysosomes. Concerning the liver, the action of monensin in vitro or in perfused liver, showed an altered secretion of protein and altered transport of VLDL; in bile-fistula rats, monensin caused a decrease of bile flow, altered protein profile and bile acids secretion. Because the effects of monensin seem to be complicated, in this note it has been studied the action of monensin on the morphology of liver cells to have a picture not only of the parenchymal cells, but also of the sinusoidal cells, which cooperation with the general liver functions become increasingly evident. The results obtained after staining of liver biopsies with Sudan Black, Sudan III and Sudan IV showed that monensin induces a diffuse cholestasis and islands of hepatocytes in steatosis, in agreement with the data in literature. Cells lining the sinusoid with phagocytic activity and that might be identified with fat-storing cells, showed an increase of their lipid droplets that might be attributed to vitamin A.

Animals↗
PubMedDate not supplied

Modulation of neutrophil functions by a beta-interferon of human origin.

The effects of a beta interferon (beta-IFN) of human origin on different parameters of human neutrophil functioning were evaluated in vitro. In the concentration range 10(2)-10(4) IU/ml beta-IFN enhanced superoxide anion (O2-) production evoked by the peptide N-formylmethionyl-leucylphenylalanine (FMLP), 10(-7) M, when O2- production elicited by FMLP in the absence of beta-IFN treatment was 2.43 +/- 0.32 nmol cytochrome C reduced/10(6) cells/min. The enhancement afforded by 10(3) and 10(4) IU/ml beta-IFN was statistically significant. When FMLP-induced O2- generation was 4.55 +/- 0.3 nmol cytochrome C reduced/10(6) cells/min, no increase was detected after beta-IFN treatment. Phagocytosis was enhanced by beta-IFN in one case, with no effect in four others. Chemotaxis was not affected by exposure to beta-IFN. These results indicated that beta-IFN could exert modulating effects on some neutrophil functions that varied according to the extent of cell response to the stimuli.

Chemotaxis, Leukocyte↗
PubMedDate not supplied

Excitatory amino acid signal transduction in cerebellar cell cultures.

In primary cultures of cerebellar granule cells excitatory amino acid recognition sites are coupled with the stimulation of inositol phospholipid (PI) hydrolysis, cGMP formation and 45Ca2+ uptake. Mg2+, 2-amino-5-phosphonovalerate (APV) and phencyclidine (PCP) potently inhibit signal transduction in response to N-methyl-D-aspartate (NMDA), glutamate (GLU) and aspartate (ASP). Activation by quisqualate (QUIS) is transduced selectively into stimulation of PI hydrolysis and this response is not sensitive to inhibition by Mg2+, APV and PCP. Activation by kainate (KA) is transduced into potent stimulation of cGMP formation and 45Ca2+ uptake. Transduction of KA signal is not affected by Mg2+ and is relatively insensitive to PCP and APV.

Amino Acids↗