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Biomedical subjects

A Rizzi

Publications and source records attributed to A Rizzi.

At least 91 records · Page 5Linked to original sources
PubMed1996

The mouse vas deferens: a pharmacological preparation sensitive to nociceptin.

The newly discovered neuropeptide, nociceptin (alias orphanin FQ), was tested for its potential direct effects, as well as for its ability to modify the electrically evoked contractions in several isolated organs suspended in vitro. The electrically stimulated mouse vas deferens is a sensitive preparation on which nociceptin exerts an inhibitory effect which is not affected by naloxone. The mouse vas deferens is therefore proposed as a bioassay for nociceptin and related compounds.

Amino Acid Sequence↗
PubMed1996

Vasoactive intestinal polypeptide-like immunoreactivity in astrocytes of the human brain.

Vasoactive intestinal polypeptide-like immunoreactive (VIP-LIR) astrocytes were found in the subcortical white matter of the human forebrain parietal lobe. Astrocytes expressing VIP-LIR represented a minority (0.97%) of the GFAP-stained astrocyte population in the white matter. The close anatomical relationship between the VIP-LIR astrocyte bodies and processes and the brain vasculature strongly suggests that they may play a role in the local control of blood flow and of the barrier properties of the vessel walls.

Astrocytes↗
PubMed1996

Receptors for kinins in the human isolated umbilical vein.

1. The human umbilical vein has been found to contract in response to bradykinin (BK) and desArg9BK. 2. The rank order of potency of agonists, in the presence of the B1 receptor antagonist Lys[Leu8]desArg9BK, is as follows: [Hyp3, Tyr(Me)8]BK (pD2 8.88) = [Hyp3]BK (pD2 8.86) = LysBK (pD2 8.81) > or = BK (pD2 8.60) >> [Aib7]BK (pD2 6.38) >> desArg9BK and LysdesArg9BK (inactive). 3. Hoe 140 (pA2 8.42) inhibits the effects of BK while other B2 receptor peptide antagonists are very weak and WIN 64338 is practically inactive. 4. Venoconstrictor responses to desArg9BK of fresh tissues increase with time during the in vitro incubation and reach a maximum after 4-6 h. The activity of Hoe 140 (pA2 5.48) is negligible against B1 receptor agonists. 5. When measured in the presence of the selective B2 receptor antagonist Hoe 140 (400 nM), the order of potency of kinin related peptides on the B1 receptor is Lys[desArg9]BK (pD2 8.60) > desArg9BK (pD2 6.69). BK, LysBK, [Hyp3]BK and other B2 receptor agonists are inactive. 6. The B1 receptor antagonist, Lys[Leu8]desArg9BK (pA2 7.99), inhibits the response of the human vein to B1 receptor agonists (LysdesArg9BK or desArg9BK), but do not alter the effect of BK. 7. The results summarized in this paper indicate that the human isolated umbilical vein is a sensitive preparation containing both B1 and B2 receptors. The human B2 receptor shows some similarity with that of the rabbit (at least for agonist potencies) and differs from the B2 receptor of the guinea-pig. Compared to the rabbit B1 receptor, the human B1 receptor shows low sensitivity to peptides that lack the N-terminal Lys.

Adult↗
PubMed1996

Characterization of endothelin receptors in the human umbilical artery and vein.

The aim of the present study was to characterize pharmacologically endothelin receptors that are present in human umbilical vessels. 2. Endothelin-1 (ET-1) and endothelin-2 (ET-2) are potent stimulants of both the human umbilical artery (pEC50 7.9 and 7.5) and vein (pEC50 8.1 and 8.0). Endothelin-3 (ET-3) is inactive on the artery but contracts the vein (pEC50 7.6). IRL1620 is inactive in both vessels. The order of potency of agonists is suggestive of a typical ET(A) receptor in the artery (ET-1 = ET-2 > > ET-3) and a mixture of ET(A) and ET(B) receptors in the vein (ET-1 = ET-2 > or = ET-3). 3. The selective ET(A) receptor antagonist, BQ123, competitively inhibits the effect of ET-1 in the human umbilical artery (pA2 6.9), while in the vein, only a mixture of BQ123 and BQ788 (a selective ET(B) antagonist) weakly displaces to the right of the cumulative concentration-response curve to ET-1. Contractions induced by ET-3 in the vein are inhibited by BQ788 (pA2 7.6), but not by BQ123. 4. Inhibition of Ca2+ channels by nifedipine (0.1 microM) is accompanied by a significant decrease of the maximal response to ET-1 by 40% in the artery and by 30% in the vein. The response of the vein to ET-3 is almost abolished by nifedipine. 5. The results indicate that: (i) endothelins contract the human isolated umbilical artery via stimulation of an ET(A) receptor type; (ii) the contraction induced by ET-1 in the vein is mediated by both ET(A) and ET(B) receptors, while ET-3 stimulates the ET(B) receptor; (iii) the contribution of Ca2+ channels to the contraction mediated by the ET(B) receptor appears to be more important than to that mediated by the ET(A) receptor.

Adult↗
PubMed1996

VIP-like immunoreactivity within neurons and perivascular neuronal processes of the human cerebral cortex.

Using indirect immunocytochemical techniques, neurons with VIP (Vasoactive Intestinal Polypeptide)-like immunoreactivity (ir) have been demonstrated in the human cerebral cortex of the parietal lobe. In all the cortical layers containing positive neurons, perivascular immunoreactive neuronal processes have been detected: in arterioles, they are located in the adventitial and smooth muscle layers; in capillaries, they establish tight anatomical relations with the endothelium-pericyte layer and the perivascular glial sheath. Bodies of positive neurons have also been seen adhering to capillary walls. The detection of perivascular VIP-like ir provides morphological evidence of the role played by this polypeptide in the regulation of the cerebral blood flow. Moreover, the relationships between immunoreactive neuronal processes and perivascular glia might corroborate the suggestion that VIP is involved in the functioning of the blood-brain barrier.

Antibodies, Monoclonal↗
PubMed1996

Long-term variations of serum laminin and procollagen III peptide in chronic HCV hepatitis after alpha-interferon therapy.

Twenty-three out of 40 patients affected by chronic HCV hepatitis responded (i.e. aminotransferases returned to normal) after 6-month treatment with 6 MU tiw of recombinant alpha-interferon 2a (IFN); in 11 (Group 1), the remission was maintained for a mean observation time of 33.15 months (range 20-50) after withdrawal of therapy; 12 (Group 2) relapsing after IFN withdrawal, were treated again obtaining in 10 a second response. Seventeen did not respond (Group 3). Serum markers of connective tissue metabolism (laminin and aminoterminal peptide of type III procollagen -NPIIIP-) were assayed in all patients before treatment and every 6th month, to evaluate long-term effects of IFN therapy. In non-responders, NPIIIP after treatment was not different from baseline, while laminin significantly increased at 6 and 12 months; in responders, NPIIIP decreased significantly after therapy, maintaining values lower than baseline on long-term observation. Laminin decreased significantly six months after the end of therapy and remained lower than baseline in all sustained responders. In this group, the drop in laminin was progressive, whereas in Group 2, laminin showed only a slight decrease on long-term control. Our data show that these serum markers persistently decrease in sustained responders to IFN, while in relapsed cases, prolonged therapy is needed to obtain minor effects on laminin; on the contrary, in non-responders, NPIIIP remains unchanged and laminin significantly increases, suggesting a persistence of active fibrogenesis.

Antiviral Agents↗
PubMed1996

Pulmonary actinomycosis: surgical considerations.

Pulmonary actinomycosis is a rare disease. Of 2,247 patients presenting with a radiological pulmonary opacity, 13 (0.6%) were identified with pulmonary actinomycosis in a 13 year period. Twelve of the 13 patients underwent thoracotomy and one had clinical diagnosis and subsequent medical treatment alone. Neither mortality nor major complications were observed. One patient had recurrent disease after surgery. The other surgical patients are well and free from disease at a minimum 6 month follow-up. Diagnosis of actinomycosis is frequently difficult because it often infects pre-existing cavitary disease in the lung. As a consequence, the infection may progress to stages which will not respond to medical treatment alone. Surgery then provides the best method to achieve diagnosis and ultimate treatment.

Actinomycosis↗
PubMed1995

Dynamics of peak dispersion in capillary zone electrophoresis including wall adsorption I. Theoretical model and results of simulation.

A mathematical model is described for the simulation of peak profiles in capillary zone electrophoresis taking wall adsorption into account. It is based on such physico-chemical relations as mass balance equations, sorption rate equations and appropriate boundary conditions. The numerical solution of the model is carried out, allowing the depiction of the concentration profile of the sample in the capillary as a result of the dynamics of the processes involved, which depend on a number of input parameters: rate constants, adsorption isotherms, column dimensions, field strength etc. Four cases are discussed in detail, namely those with either slow or fast adsorption kinetics and linear or nonlinear isotherms.

Adsorption↗
PubMed1995

Intracavitary therapy of neoplastic effusions with cytokines: comparison among interferon alpha, beta and interleukin-2.

Preliminary studies have suggested that the intracavitary administration of cytokines may represent a new effective palliative therapy of malignant effusions. To define further the therapeutic role of cytokines in the treatment of neoplastic fluid accumulation, 70 cancer patients with pleural, pericardial or peritoneal cytologically proven neoplastic effusions were randomized to receive intracavitary cycles with interleukin-2 (IL-2; 6 x 10(6) IU), interferon (IFN alpha; 2 x 10(7) U) or IFN beta (6 x 10(6) U) every week for 2 or 3 weeks. A clinical control of fluid accumulation was obtained in 39/70 (56%) patients. In patients with mesothelioma, the response rate was significantly higher with IL-2 than with IFN alpha or -beta, while there was no difference in patients with tumors other than mesothelioma. Moreover, the duration of the period during which drainage was not required was significantly longer in patients treated with Il-2 than in the other groups. Toxicity was low in all patients. According to preliminary data, this study demonstrates that intracavitary administration of cytokines, including IL-2, IFN alpha and -beta, is a new well-tolerated palliative therapy for malignant effusions, with an efficacy substantially comparable to that described with the most commonly used treatments with tetracyclines or cytostatic agents.

Adult↗
PubMed1995

Results of surgical management of tuberculosis: experience in 206 patients undergoing operation.

Between January 1978 and December 1990, 206 operations for pulmonary tuberculosis were performed at our institution, a former sanatorium located in northern Italy. Patients with tuberculoma and pleural tuberculous disease were excluded from this series. Cavitary sequelae, bronchiectases, and hemoptysis were the most common indications for resection. Scar cancer and mycetoma were associated diseases in more than 60% of the patients. Healing was achieved in 90% of the patients. Operative mortality was 3%. Overall morbidity was 29.1%. Patient stratification showed that sputum-positive patients had a higher morbidity (30%) and a lower healing rate (86.2%). Before operation, an accurate assessment of both the performance status and the functional reserve of the surgical candidates is emphasized. Despite a high complication rate, aggressive surgical treatment of drug-resistant tuberculosis or its stabilized sequelae is warranted to achieve anatomobiological eradication of the disease, thus avoiding long-term troublesome complications.

Adolescent↗
PubMed1995

Impact of autologous blood transfusion on blood support in general thoracic surgery: analysis of 969 patients over a 5-year period.

Autologous blood transfusion (ABT) is increasingly used in order to avoid transfusion-related risks. The effectiveness of this simple and feasible procedure depends on several factors, such as the timing of surgery, the patient's overall condition and, last but not least, the pre-disposition of the medical team towards the routine use of ABT. We report our experience in blood support with ABT for general thoracic surgical patients, indicating an overall partially satisfactory outcome due to a limited use of the procedure. In 1992, 61 patients (38%) received autologous blood only, as compared to 9 patients (6%) who had received ABT in 1989. The average pre-deposit per patient ratio in 1992 was 1.2 units, which provided insufficient autologous blood support. In the same period, only 23 patients were subjected to acute normovolemic hemodilution (ANH). However, we noted a reduction of homologous transfusions from 2.9 +/- < 2.1 in 1989 to 2.0 +/- < 1.5 in 1992 (P < 0.01). In addition, we observed that a single pre-deposit was not enough to enhance erythropoiesis and to improve post-operative red blood cell rescue when performed in patients with Hb > 11 g%. Based on our data, we emphasize a more extensive move to ANH, along with pre-deposit, in order to avoid unnecessary homologous blood transfusions.

Blood Transfusion↗
PubMed1994

Improved separation of diastereomeric derivatives of enantiomers by a physical network of linear polyvinylpyrrolidone applied as pseudophase in capillary zone electrophoresis.

Diastereomeric analytes were separated using capillary zone electrophoresis with polyvinylpyrrolidone as polymeric additive to the buffer solution. As test substances derivatives of D- and L- alpha-amino and alpha-hydroxy acids formed by reaction with (+)-O,O'-diacetyl- and (+)-O,O'-dibenzoyl-L-tartaric anhydride, respectively, were used. The physical network formed by the linear polymer is supposed to act as a kind of pseudophase. It was found that the network affects the mobility of diastereomeric compounds to a different extent, enhancing the selectivity of the system. In nearly all cases of aromatic acids the diastereomer carrying the D-amino acid was more strongly retained than the L-isomer, as opposed to the situation with aliphatic acids.

Amino Acids↗
PubMed1993

alpha-Interferon in the treatment of chronic viral hepatitis: effects on fibrogenesis serum markers.

Forty patients with chronic viral hepatitis or active cirrhosis (33 anti-HCV positive) entered a recombinant human alpha 2A interferon randomized trial. Twenty-one subjects were treated with 6 million units (MU) three times per week for 6 months. Nineteen were not treated. Six months later in 12 patients of the treated group (60% of the evaluable 20) with normalized serum aminotransferases levels (responders), fibrogenesis serum markers (NPIIIP and laminin) were significantly lower than baseline. In the untreated patients and in non-responders NPIIIP and laminin were unchanged. Semi quantitative histological evaluation (allotting scores for inflammation, necrosis and fibrosis) confirmed a significant improvement of necro-inflammation in the responders. These data suggest that alpha-IFN treatment may decrease stimuli for fibrogenesis by reducing liver inflammation and necrosis, thus preventing evolution to cirrhosis.

Adult↗