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Biomedical subjects

F Rossi

Publications and source records attributed to F Rossi.

At least 199 records · Page 11Linked to original sources
PubMed1998

L-Cysteinesulfinic acid modulates cardiovascular function in the periaqueductal gray area of rat.

L-Cysteinesulfinic acid (CSA) involvement in modulating periaqueductal gray (PAG) pressor neurons has been evaluated in the rat. Intra-PAG CSA induced an increase in mean blood pressure partially antagonized by (2S)-alpha-ethylglutamic acid (EGA), a group II metabotropic glutamate receptors (mGluRs) antagonist. Conversely, the NMDA antagonist, DL-AP5, or the mGluRs antagonists, (+)-MCPG, UPF523, or (RS)-alpha-methylserine-O-phosphate (MSOP), were devoid of any activity on the CSA effect. These data show that the excitatory amino acid CSA, probably by stimulating an mGluR, contributes with glutamate in modulating cardiovascular function at the PAG matter.

Animals↗
PubMed1998

Anterior sagittal transanorectal approach to the posterior urethra in the pediatric age group.

PURPOSE: Surgical access to the posterior urethra is often difficult and several surgical solutions have been proposed. We suggest an anterior sagittal transanorectal approach based on splitting the anterior rectal wall only. This alternative technique provides excellent exposure to the retrourethral region, permitting simple and safe surgery. MATERIALS AND METHODS: Between 1994 and 1996 we performed surgery via the anterior sagittal transanorectal approach in 8 patients with a mean age of 9.06 years. Patients included 1 girl with a posttraumatic urethrovaginal fistula, 3 with intersex disorders (2 with mixed gonadal dysgenesis raised as boys and 1 with male dysgenetic pseudohermaphroditism with an enlarged urtricle) and 4 boys (1 with penile agenesis raised as girl, 2 with urethral duplication and 1 with prostatic rhabdomyosarcoma). The patient was placed in a knee-chest position. A midline sagittal incision was made through the anterior anorectal wall only and deepened through the perineal body to expose the posterior urethra and retrovesical space. After the pathological condition was corrected the anterior rectal wall and perineal body were reconstructed. The operation was completed with protective colostomy. In our final patient with prostatic rhabdomyosarcoma the anterior sagittal transanorectal approach was used without colostomy. Anorectal manometry was done 6 months postoperatively. RESULTS: All patients were completely continent of stool and urine. Convalescence was unremarkable in all cases. Postoperative manometry in 7 patients revealed no differences from preoperative measurements. CONCLUSIONS: This procedure should be considered a useful alternative to other techniques for various congenital and acquired pelvic disorders.

Adolescent↗
PubMed1998

Identification and clustering of dairy propionibacteria by RAPD-PCR and CGE-REA methods.

A total of 67 classical propionic acid bacteria (PAB) strains, 10 of which were from type culture collections and 57 from milk, typical Italian cheeses, acid whey and feed flour of different regions, were analysed by Randomly Amplified Polymorphic DNA (RAPD-PCR) and by Conventional Gel Electrophoresis Restriction Endonuclease Analysis (CGE-REA). The genotypic traits achieved using RAPD-PCR with three primers (OPL-01, OPL-02 and OPL-05) and SmaI CGE-REA patterns were compared by numerical analysis and allowed a clear distinction of four clusters corresponding to the currently described species of classical propionibacteria according to type and reference strains positions. No discrepancies exist in species recognition between the two methods; 36 isolates were identified as Propionibacterium freudenreichii, 15 as P. jensenii, four as P. acidipropionici and two as P. thoenii. Many differences, however, were observed in intraspecific clustering. Numerical comparison of RAPD-PCR profiles appeared to be a suitable method for highlighting the presence of particular phenotypic characters, while intraspecific differentiation obtained by CGE-REA analysis allowed association of strains at high similarity levels on the basis of their geographical origin.

Animals↗
PubMed1998

Structure of cyclic peptides: the crystal and solution conformation of cyclo(Phe-Phe-Aib-Leu-Pro).

A solid-state and solution conformation analyses of the cyclopentapeptide cyclo(Phe-Phe-Aib-Leu-Pro) has been carried out by X-ray diffraction and nuclear magnetic resonance techniques. The structure of the hexagonal crystals, grown from a methanol solution [a = b = 16.530(4) A, c = 21.356(9) A, space group P6(5), Z = 6], shows the presence of one intramolecular N-H ..O=C hydrogen bond with the formation of a gamma-turn (C7). The Aib3 residue, at the center of the gamma-turn, presents unexpected values of the torsion angles [phi = 70.5 degrees and psi = -73.8 degrees], which have been observed only once before for this helicogenic residue. A cis peptide bond occurs between Leu4 and Pro5; all other peptide bonds are trans. The overall conformation for the cyclopentapeptide with one cis-peptide bond on one side and an intramolecular gamma-turn on the opposite side results in an equatorial topology of the side-chains of the Phe1, Phe2 and Leu4 residues. Indeed, the Calpha-Cbeta and Cbeta-Cgamma bonds of these residues lie approximately in the mean plane of the cyclic ring system. The structure is compared with data in the literature on cyclic pentapeptides. In addition the Pro-Phe-Phe moiety shows a conformation similar to that observed in other larger cyclic bioactive peptides, which indicates a reduced number of conformations for this sequence. The solution study was carried out in three different solvent systems: chloroform, acetonitrile and methanol in the temperature interval 220-300 K. In all three solvents the room temperature spectra show that the peptide is conformationally nonhomogeneous. In acetonitrile at low temperatures it is possible to reduce the conformational equilibrium to two predominant conformers which differ for the cis-trans isomerism of the Leu4-Pro5 peptide bond.

Magnetic Resonance Spectroscopy↗
PubMed1998

Cerebral hemodynamics in primary headaches: the transcranial Doppler experience.

This paper is an extensive review of the use of transcranial Doppler (TCD) devices in "vascular" forms of headache, and a discussion of the possible occurrence of nonunivocal results, particularly in migraine with or without aura. Despite the large variability in findings, TCD is a noninvasive, safe, and reproducible method for studying hemodynamic phenomena which characterize the clinical profile of migraine and cluster headache attacks. Similarly, it can detect cerebrovasomotor reactivity to external/internal environmental stimuli, as well as responses to pharmacological (therapeutic or diagnostic) agents. Possible future applications of TCD in monitoring vasomotor changes in response to selective stimuli (sympathetic, neuropeptidergic, etc.) are also considered.

Cerebrovascular Circulation↗
PubMed1998

Business management of headache centers.

Economic evaluation of the costs and benefits of a headache center or unit has become very important for headache specialists. Many of the problems concerning this "financial" approach to headache derive from the model of organization of the Headache Unit, which is dependent on the various approaches to healthcare practiced in the country considered. So far there are two models of headache center that are generally considered: the hospital-based center and the independent center. An argument favoring hospital-based headache clinics is the lower costs, primarily because of their functional connection with the services of a general hospital, i.e., neuroradiology, neurophysiology, routine laboratory analysis, etc. Another is that the headache specialist has the possibility to visit the patients presenting to the emergency room in the acute phase of headache. Independent clinics have greater costs, but are equally as effective as hospital-based models.

Ambulatory Care Facilities↗
PubMed1998

Successful meropenem therapy of a brain abscess and meningitis arising from acute purulent otomastoiditis: case report.

We describe a case of a 25-year-old female with an acute left otomastoiditis, accompanied by a left temporal extradural abscess with moderate perifocal edema and meningitis. Intravenous meropenem (2 g 8-hourly) and intravenous methylprednisolone (40 mg once daily) were commenced empirically. Teicoplanin (400 mg once daily intravenously) was added after 5 days when culture results were available. Teicoplanin was discontinued on day 25 but meropenem and methylprednisolone were continued for a further 15 days, after which the abscess completely resolved without sequelae. No treatment-induced adverse effects or seizures were observed. Thus, in selected patients, antibacterials (in conjunction with a corticosteroid) may be successfully used without surgery to treat brain abscesses and in such circumstances meropenem is a useful option for empiric therapy.

Adult↗
PubMed1998

Antibiotic prophylaxis for surgical procedures: a survey from an Italian university hospital.

The aims of this study were: 1) to evaluate the surgical prophylaxis regimens adopted by surgeons of the University Hospital of the Faculty of Medicine and Surgery of the 2nd University of Naples during the period January-March 1996; 2) to compare uses of antibiotic prophylaxis carried out in surgical departments to standard international guidelines; 3) to assess the cost of surgical prophylaxis. Data from 1,085 surgical patients from January 1, 1996 to March 31, 1996, were collected, reporting surgical department, type of surgery, antibiotics used, dosage, and length of the prophylactic treatment. Collected data underwent computer-assisted evaluation and comparison to the international guidelines. Four-hundred and twenty-five patients with concomitant diseases, who did not meet inclusion criteria into standard guidelines, were excluded from the study. The remaining patients (N = 660) underwent clean or clean-contaminated surgical procedures. Two-hundred and twenty patients underwent clean surgical procedures, with prophylactic antibiotic treatment lasting from 1.1 +/- 0.3 to 4.6 +/- 2.8 days. Four-hundred and forty patients underwent a clean-contaminated surgical procedure, with antibiotic prophylaxis lasting from 3.6 +/- 2.4 to 5.2 +/- 3.7 days. Third generation cephalosporins were the most frequently used antibiotics both in patients undergoing clean (163 patients = 74.1%), and clean-contaminated surgical procedures (321 patients = 73%). The resulting costs were about ten-fold higher than costs of antibiotic prophylaxis carried out according to international guidelines. In conclusion, our research highlights the habit of non-compliance with standard guidelines for antibiotic prophylaxis both in terms of drug choice and treatment duration.

Antibiotic Prophylaxis↗
PubMed1998

Bioavailability of timolol and aceclidine after ocular instillation in the rabbit.

The bioavailability of timolol and aceclidine after the ocular instillation of each drug (timolol 0.5% or aceclidine 2%) or both combined (timolol 0.5% + aceclidine 2%) has been evaluated in rabbits. 15 male albino rabbits were treated by the instillation of timolol and aceclidine alone or combined in the conjunctival sac of the right eye. Timolol concentrations in humor aqueous were assayed at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 6 hr after instillation by high-performance liquid chromatography (HPLC). Aceclidine was assayed by a pharmacodynamic method: pupillary diameter at the following time intervals 0 (basal value), 1 min, 5 min, 30 min, 1 hr, 2 hr, 4 hr, 6 hr after treatment. Our results demonstrated that no differences in timolol and aceclidine bioavailability were found between simple-drug preparations and their combination.

Administration, Topical↗
PubMed1998

[Hospital intensive monitoring of adverse reactions of ACE inhibitors].

BACKGROUND AND AIMS: Angiotensin II converting enzyme (ACE) inhibitors represent one of the most important pharmacological instruments for the treatment of arterial hypertension and are currently also used for other cardiovascular indications. The actions of ACE-inhibitors mainly depends on blocking the ACE enzyme in the renin-angiotensin-aldosterone system. However, the ACE enzyme also has a kinase activity. The inhibition of this enzyme may also cause an accumulation of tissue mediators (bradykinin) responsible for a number of adverse reactions. METHODS: An intensive hospital monitoring programme of adverse reactions to drugs, known as MIO[symbol: see text]'96, was carried out by the Centre of Pharmacoepidemiology of the Faculty of Medicine and Surgery at the Second University of Naples during the period 25 March-18 April 1996. The main aims of the programme were to highlight the incidence of adverse reactions to the drugs monitored and the definition of the risk/benefit ratio taking account of the main physiological and pathophysiological variations of patients. This paper reports the results of the programme of adverse effects correlated to the use of ACE-inhibitors. A total of 175 records were compiled for 105 patients receiving antihypertensive treatment with a number of ACE-inhibitors (captopril, enalapril, lisinopril); a very high mean incidence of adverse events was documented (22%) without any severe undesirable effects. RESULTS: The following adverse events were documented (the cumulative incidence is given in brackets): dysgeusia (17%), flush (8%), headache (33%), exanthema (17%), diarrhoea (8%), vertigo (8%), xerostomia (8%). Coughing was not reported in any patient. CONCLUSIONS: Further periods of intensive monitoring will be required to obtain a greater quantity of data from the Intensive Monitoring of adverse events through the MIO[symbol: see text]'97 programme.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Targeted overexpression of the neurite growth-associated protein B-50/GAP-43 in cerebellar Purkinje cells induces sprouting after axotomy but not axon regeneration into growth-permissive transplants.

B-50/GAP-43 is a nervous tissue-specific protein, the expression of which is associated with axon growth and regeneration. Its overexpression in transgenic mice produces spontaneous axonal sprouting and enhances induced remodeling in several neuron populations (; ). We examined the capacity of this protein to increase the regenerative potential of injured adult central axons, by inducing targeted B-50/GAP-43 overexpression in Purkinje cells, which normally show poor regenerative capabilities. Thus, transgenic mice were produced in which B-50/GAP-43 overexpression was driven by the Purkinje cell-specific L7 promoter. Uninjured transgenic Purkinje cells displayed normal morphology, indicating that transgene expression does not modify the normal phenotype of these neurons. By contrast, after axotomy numerous transgenic Purkinje cells exhibited profuse sprouting along the axon and at its severed end. Nevertheless, despite these growth phenomena, which never occurred in wild-type mice, the severed transgenic axons were not able to regenerate, either spontaneously or into embryonic neural or Schwann cell grafts placed into the lesion site. Finally, although only a moderate Purkinje cell loss occurred in wild-type cerebella after axotomy, a considerable number of injured transgenic neurons degenerated, but they could be partially rescued by the different transplants placed into the lesion site. Thus, B-50/GAP-43 overexpression substantially modifies Purkinje cell response to axotomy, by inducing growth processes and decreasing their resistance to injury. However, the presence of this protein is not sufficient to enable these neurons to accomplish a full program of axon regeneration.

Animals↗
PubMed1997

HsN3 proteasomal subunit as a target for human immunodeficiency virus type 1 Nef protein.

HIV-1 Nef protein is important for pathogenicity, but its biochemical function remains obscure. To clarify its role, a yeast two-hybrid system (ths) screening was utilized to identify Nef cellular partners. Of 79 yeast clones harboring cDNAs for putative Nef binding proteins, 27 (34%) contained the coding region for HsN3 proteasomal subunit. HsN3 behaved as bona fide Nef partner in ths control crosses. Nef-HsN3 interaction was confirmed by in vitro binding experiments. In particular, recombinant Nef was able to capture the HsN3 subunit from a natural proteasome preparation. In Nef, the interacting region was mapped within aa 34-143, which span the structured portion of the protein, including the SH3-binding domain. In HsN3, Nef-binding portion was restricted to aa 73-249, and the tract 219-249-reminiscent of SH3 domain N-terminal 3/5ths-was shown to be essential, though not sufficient. Attempts to purify a Nef-HsN3 complex from transfected COS7 cells were unsuccessful. However, Nef was found to markedly downregulate intracellular levels of both a coexpressed HsN3 and the endogenous simian homologue. These results suggest that Nef, by binding to a subunit, might alter proteasome function in infected cells.

Amino Acid Sequence↗
PubMed1997

Thrombomucin, a novel cell surface protein that defines thrombocytes and multipotent hematopoietic progenitors.

MEP21 is an avian antigen specifically expressed on the surface of Myb-Ets-transformed multipotent hematopoietic precursors (MEPs) and of normal thrombocytes. Using nanoelectrospray tandem mass spectrometry, we have sequenced and subsequently cloned the MEP21 cDNA and named the gene thrombomucin as it encodes a 571-amino acid protein with an extracellular domain typical of the mucin family of proteoglycans. Thrombomucin is distantly related to CD34, the best characterized and most used human hematopoietic stem cell marker. It is also highly homologous in its transmembrane/intracellular domain to podocalyxinlike protein-1, a rabbit cell surface glycoprotein of kidney podocytes. Single cell analysis of yolk sac cells from 3-d-old chick embryos revealed that thrombomucin is expressed on the surface of both lineage-restricted and multipotent progenitors. In the bone marrow, thrombomucin is also expressed on mono- and multipotent progenitors, showing an overlapping but distinct expression pattern from that of the receptor-type stem cell marker c-kit. These observations strengthen the notion that the Myb-Ets oncoprotein can induce the proliferation of thrombomucin-positive hematopoietic progenitors that have retained the capacity to differentiate along multiple lineages. They also suggest that thrombomucin and CD34 form a family of stem cell-specific proteins with possibly overlapping functions in early hematopoietic progenitors.

Animals↗
PubMed1997

Monitoring protein-protein interactions in intact eukaryotic cells by beta-galactosidase complementation.

We present an approach for monitoring protein-protein interactions within intact eukaryotic cells, which should increase our understanding of the regulatory circuitry that controls the proliferation and differentiation of cells and how these processes go awry in disease states such as cancer. Chimeric proteins composed of proteins of interest fused to complementing beta-galactosidase (beta-gal) deletion mutants permit a novel analysis of protein complexes within cells. In this approach, the beta-gal activity resulting from the forced interaction of nonfunctional weakly complementing beta-gal peptides (Deltaalpha and Deltaomega) serves as a measure of the extent of interaction of the non-beta-gal portions of the chimeras. To test this application of lacZ intracistronic complementation, proteins that form a complex in the presence of rapamycin were used. These proteins, FRAP and FKBP12, were synthesized as fusion proteins with Deltaalpha and Deltaomega, respectively. Enzymatic beta-gal activity served to monitor the formation of the rapamycin-induced chimeric FRAP/FKBP12 protein complex in a time- and dose-dependent manner, as assessed by histochemical, biochemical, and fluorescence-activated cell sorting assays. This approach may prove to be a valuable adjunct to in vitro immunoprecipitation and crosslinking methods and in vivo yeast two-hybrid and fluorescence energy transfer systems. It may also allow a direct assessment of specific protein dimerization interactions in a biologically relevant context, localized in the cell compartments in which they occur, and in the milieu of competing proteins.

Animals↗
PubMed1997

Regulation of blood pressure by L-arginine-nitric oxide pathway within the superior colliculus of rats.

Injection into the superior colliculus of anaesthetised rats of the nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME; 1 micromol), but not its inactive enantiomer N(omega)-nitro-D-arginine methyl ester (D-NAME; 1 micromol), significantly (P < 0.01) increased the mean arterial blood pressure. Injection to the superior colliculus of L-arginine (L-Arg; 1 micromol), the substrate for NO synthase, significantly (P < 0.01) lessened the pressor effect of L-NAME, while D-arginine (D-Arg; 1 micromol) did not affect it. L-Arg (7.5 micromol), but not D-Arg (7.5 micromol) administered at the peak of the pressor response to L-NAME (1 micromol) also partially reversed this pressor response (P < 0.05). These data would suggest that endogenously produced NO acts within the superior colliculus to modulate the arterial blood pressure.

Analysis of Variance↗
PubMed1997

Reestablishment of the olivocerebellar projection map by compensatory transcommissural reinnervation following unilateral transection of the inferior cerebellar peduncle in the newborn rat.

It is unclear whether reparative processes in the injured mammalian brain are able to restore the topographic organisation of neuronal connections. To address this question, we have investigated the plasticity of the olivocerebellar system. This pathway has a precise topographic arrangement, in which subsets of inferior olivary neurons project to parasagittally oriented Purkinje cell compartments. Following unilateral transection of the inferior cerebellar peduncle in newborn rats, axons from the contralateral projection cross the cerebellar midline and reinnervate the deafferented hemicerebellum. By this experimental approach, we first analysed the behaviour of calcitonin gene-related peptide (CGRP)-immunoreactive climbing fibres. This marker is transiently expressed by a subset of developing inferior olivary axons, which terminate in the cerebellar cortex into several parasagittal strips. We show that transcommissural axons reestablish the original pattern of climbing fibre bands within a few days after lesion. Then, in adult animals injured at birth, we assessed whether the newly formed climbing fibre bands align with zebrin II+/- Purkinje cell compartments, as in normal conditions. The newly formed projection is organised in parasagittally oriented strips which mirror the distribution of their counterparts on the intact side and are precisely aligned to the heterogeneous Purkinje cell compartments. In addition, the patchy distribution of olivo-nuclear fibres suggests that specific reinnervation is also achieved in the deep nuclei. Thus, transcommissural olivocerebellar reinnervation is not random, but it is regulated by selective interactions between distinct subsets of olivocerebellar axons and target neurons aimed at reestablishing the correct projection map.

Animals↗
PubMed1997

Evidence for non-adrenergic non-cholinergic contractile responses in bovine and swine trachea.

Non-adrenergic non-cholinergic (NANC) contraction of airway smooth muscle has been observed in some but not all animal species. The aim of this study was to investigate the NANC-contractile responses in bovine and swine trachea. Proximal and distal bovine and swine trachea were cut in strips and placed in 10 ml organ baths equilibrated in Krebs Henseleit (KH) solution and electrically stimulated (10 sec, 60 V, 2 ms, 4, 10 and 30 Hz). Contractile frequency response curves performed in the presence of the muscarinic antagonist, atropine (100 mM), the angiotensin converting enzyme inhibitor, captopril (1 microM) and the neutral endopeptidase inhibitor, thiorphan (1 microM), added 30 min prior to electrical field stimulation (EFS). In some tissues, incubated with atropine thiorphan and captopril, were also evaluated the effects of a pretreatment with capsaicin (10 microM) or a selective NK1 receptor antagonist, SR 14033 (100 nM) added to the baths 30 min prior to EFS. Bovine and swine proximal and distal tracheal preparations contracted in a frequency-dependent manner to EFS (4, 10 and 30 Hz). Some experiments were also performed with substance P (0.1 nM to 1 microM) in absence or in presence of SR 14033 (10 nM or 100 nM). At the maximum frequency tested (30 Hz), the contractile response elicited in bovine proximal and distal preparations was 194.5 +/- 17.1% and 229.7 +/- 24.1%, of ACh (100 microM), respectively. Similarly, the contractile response elicited by EFS (30 Hz) in swine proximal and distal preparations was 187.2 +/- 12.1% and 181.6 +/- 9.2% of ACh (100 microM), respectively. In tissues incubated with atropine, a significant decrease in smooth muscle sensitivity to EFS was observed (P < 0.05). When tissues were pretreated with captopril and thiorphan, a significant increase in the contractile response to EFS (30 Hz) was observed in all tested tissue preparations (bovine, proximal 210.1 +/- 14.4%, distal 264.3 +/- 16.2%; swine, proximal 199.3 +/- 14.9%, distal 206.3 +/- 16.2%, P < 0.05). In the presence of atropine, captopril and thiorphan a significant increase in the contractile response was observed in bovine and swine distal preparations compared with tissues incubated with atropine only (P < 0.05). These effects were antagonized by a pretreatment with a selective NK1 receptor antagonist, SR 14033. A pretreatment with capsaicin statistically (P < 0.05) enhanced EFS-induced contraction in all tested preparations respect to tissues incubated with atropine, thiorphan and captopril. Substance P induced a concentration dependent contraction of bovine and swine isolated tracheal preparations which was antagonized by a pretreatment with a selective NK1 receptor antagonist, SR 14033. No significant difference in the contractile potency (EC50) nor in maximum response (Emax) was observed to exogenously administered substance P between proximal and distal tracheal preparations. These data suggest that NANC contractile responses are present in bovine and swine trachea and are more evident in distal airways.

Animals↗