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Biomedical subjects

A Rossi

Publications and source records attributed to A Rossi.

At least 181 records · Page 10Linked to original sources
PubMed2000

Anti-inflammatory cyclopentenone prostaglandins are direct inhibitors of IkappaB kinase.

NF-kappaB is a critical activator of genes involved in inflammation and immunity. Pro-inflammatory cytokines activate the IkappaB kinase (IKK) complex that phosphorylates the NF-kappaB inhibitors, triggering their conjugation with ubiquitin and subsequent degradation. Freed NF-kappaB dimers translocate to the nucleus and induce target genes, including the one for cyclo-oxygenase 2 (COX2), which catalyses the synthesis of pro-inflammatory prostaglandins, in particular PGE. At late stages of inflammatory episodes, however, COX2 directs the synthesis of anti-inflammatory cyclopentenone prostaglandins, suggesting a role for these molecules in the resolution of inflammation. Cyclopentenone prostaglandins have been suggested to exert anti-inflammatory activity through the activation of peroxisome proliferator-activated receptor-gamma. Here we demonstrate a novel mechanism of antiinflammatory activity which is based on the direct inhibition and modification of the IKKbeta subunit of IKK. As IKKbeta is responsible for the activation of NF-kappaB by pro-inflammatory stimuli, our findings explain how cyclopentenone prostaglandins function and can be used to improve the utility of COX2 inhibitors.

Amino Acid Sequence↗
PubMed2000

Mass spectrometry of avermectins: structural determination of two new derivatives of Ivermectin B(1a).

Fragmentation pathways of Avermectins were studied by electron impact (EI), chemical ionisation (CI), electrospray ionisation (ESI) and by collision experiments. Structure characterisation was obtained using ESI combined with multi-stage (MS(n)) tandem mass spectrometry, analysis of homologues, and effects on fragment masses of H/D exchange. By these approaches the structures of two new derivatives of Avermectins were characterised.

Antiprotozoal Agents↗
PubMed2000

Role of the AZFa candidate genes in male infertility.

The AZFa region on the Y-chromosome long arm has been recently assembled in a complete sequence map contained in a contig and shown to span more than 1 Mb. It contains three genes, USP9Y, DBY and UTY, but only the former two can be at present considered candidate genes for the infertile phenotype associated with deletion of this interval. These genes have X-homologues and are expressed in many tissues, even if DBY has a shorter transcript expressed in the testis only, strengthening its role in spermatogenesis. Only few patients with gene-specific deletion have been reported and a clear genotype-phenotype relation is still lacking. While deletions or even smaller mutations in USP9Y seem to be associated with a testicular phenotype of severe hypospermatogenesis, patients with deletions of DBY may present both Sertoli cell-only syndrome and severe hypospermatogenesis. On the contrary, the phenotype of patients with deletion of both USP9Y and DBY seem to be invariably azoospermia with a testicular histology of Sertoli cell-only.

Chromosome Mapping↗
PubMed2000

Salt-tolerant phenol-degrading microorganisms isolated from Amazonian soil samples.

Two phenol-degrading microorganisms were isolated from Amazonian rain forest soil samples after enrichment in the presence of phenol and a high salt concentration. The yeast Candida tropicalis and the bacterium Alcaligenes faecoalis were identified using several techniques, including staining, morphological observation and biochemical tests, fatty acid profiles and 16S/18S rRNA sequencing. Both isolates, A. faecalis and C. tropicalis, were used in phenol degradation assays, with Rhodococcus erythropolis as a reference phenol-degrading bacterium, and compared to microbial populations from wastewater samples collected from phenol-contaminated environments. C. tropicalis tolerated higher concentrations of phenol and salt (16 mM and 15%, respectively) than A. faecalis (12 mM and 5.6%). The yeast also tolerated a wider pH range (3-9) during phenol degradation than A. faecalis (pH 7-9). Phenol degradation was repressed in C. tropicalis by acetate and glucose, but not by lactate. Glucose and acetate had little effect, while lactate stimulated phenol degradation in A. faecalis. To our knowledge, these soils had never been contaminated with man-made phenolic compounds and this is the first report of phenol-degrading microorganisms from Amazonian forest soil samples. The results support the idea that natural uncontaminated environments contain sufficient genetic diversity to make them valid choices for the isolation of microorganisms useful in bioremediation.

Alcaligenes↗
PubMed2000

Fourier transform infrared determination of CO2 evolved from carbonate in carbonated apatites.

A quantitative method based on FTIR has been developed to determine carbonate in synthetic apatites. The method measures the evolved CO2 after reaction of 50 mg apatite with 2 mL of hydrochloric acid (0.5 M) in a reaction vessel, heated to 40 degrees C. The CO2 evolved was swept by a carrier of nitrogen to a laboratory-made infrared gas cell of 39 mm pathlength and 490 microL volume. The signals were recorded as a function of time and the areas of the chemigram peaks obtained from the measurements in the wavenumber range of 2,500-2,150 cm(-1), were interpolated using a calibration curve. The method can be used to study apatites with carbonate contents below 0.2% with a sampling frequency of 8 h(-1).

Apatites↗
PubMed2000

Spinal dysraphism: a review of neuroradiological features with embryological correlations and proposal for a new classification.

Our purpose was to review the neuroradiological features of spinal dysraphism and to correlate them with clinical findings and up-to-date embryological theory. We also aimed to formulate a working classification which might prove useful in clinical practice. We reviewed series of 986 children referred to our Spina Bifida Centre in the past 24 years. There were 353 children with open spinal (OSD) and 633 with closed (skin-covered) spinal (CSD) dysraphism. By far the most common open abnormality was myelomeningocele, and all patients with OSD had a Chiari II malformation. CSD was categorised clinically, depending on the presence of a subcutaneous mass in the back. CSD with a mass mainly consisted of lipomas with dural defects and meningoceles, and accounted for 18.8 % of CSD. CSD without a mass were simple (tight filum terminale, intradural lipoma) or complex (split cord malformations, caudal regression). Our suggested classification is easy to use and to remember and takes into account clinical and MRI features; we have found it useful and reliable when making a preoperative neuroradiological diagnosis in clinical practice.

Child, Preschool↗
PubMed2000

Cognitive symptoms of mania in pure and mixed episodes evaluated with the Positive and Negative Syndrome Scale.

To investigate the clinical specificity of mixed affective patients, we compared the clinical characteristics of pure manic patients with those of mixed manic patients. The clinical symptoms of 146 bipolar inpatients hospitalized for a manic episode were assessed by means of the Positive and Negative Syndrome Scale. Mixed patients showed more positive and cognitive symptoms and among these the lack of judgement and insight was prominent. Further studies are needed to clarify the specificity of lack of insight of the mixed bipolar patients.

Adult↗
PubMed2000

Awareness of illness and outcome in schizophrenia.

The purpose of the present study was to investigate whether awareness of illness affects specific measures of outcome in schizophrenia. Patient awareness was evaluated using a shortened version of the Scale to Assess Unawareness of Mental Disorder (SUMD). Patient outcome was assessed by means of the Strauss-Carpenter scale. Our findings indicate that lack of awareness of "negative symptoms" has a considerable impact on outcome: in fact "Social Contacts" highly correlated with Blunt Affect, Anhedonia and Asociality items on the SUMD. Lack of awareness seems then to be a powerful predictor of poor outcome.

Adult↗
PubMed2000

Molecular cloning of Schistosoma mansoni calcineurin subunits and immunolocalization to the excretory system.

In order to explain the schistosomicidal effect of cyclosporin A, the hypothesis was advanced that the drug, complexed with cyclophilin, inhibits the phosphatase activity of parasite calcineurin (CN), with mechanisms similar to those operating in its immunosuppressive action. As a preparatory step to the testing of this hypothesis, we report the molecular cloning of both CN subunits in Schistosoma mansoni. The catalytic (A) subunit has a predicted sequence of 607 amino acids and shows substantial similarity to other cloned CNs, except for the carboxy-terminal end that is highly divergent. The regulatory (B) subunit consists of 169 amino acids that are 86% identical to those of the human counterpart and, from its anomalous electrophoretic mobility, it appears to be myristoylated. The results of Southern blotting experiments are compatible with the existence of multiple genes for CNA and a single gene for CNB. Western blots showed that both subunits are present at all stages of the parasite life cycle and can be detected both in the soluble and in the membrane fraction. Immunofluorescence confocal microscopy revealed a striking concentration of the anti-CNA reactivity in 6-8 discrete spots in the schistosomula and in distinct spots along the body of the adult parasite, corresponding to the expected localization of flame cells. Both patterns were confirmed by a perfect co-localization of the anti-CNA signal with that of a previously characterized anti-flame cell monoclonal antibody. The preferential confinement of schistosome CN to the protonephridial system suggests that the enzyme in the parasite may fulfil similar functions to those performed in mammalian kidneys.

Amino Acid Sequence↗
PubMed2000

Thoracic radiotherapy and daily vinorelbine as radiosensitizer in locally advanced non small cell lung cancer: a phase I study.

Experimental studies have shown that vinorelbine is a powerful radiosensitizer in vitro. To date, no reports on clinical activity of the single agent vinorelbine as radiosensitizer have been published. The aim of the present phase I study was to determine the maximum tolerated dose (MTD) of vinorelbine administered daily concurrently with thoracic radiotherapy, with or without amifostine support, in the treatment of locally advanced non small cell lung cancer. In vitro studies have shown that vinorelbine can potentiate the antitumor effects of radiation therapy. Amifostine is a sulphydril compound that has shown to protect normal tissues from chemotherapy and radiotherapy-induced toxicities. Radiotherapy lasted 6 weeks and the total dose was 55 Gy. The daily fraction was 1.8 Gy, administered 5 days a week for 5 weeks and increased to 2.0 Gy during the sixth and last week. Concurrent vinorelbine was administered daily with a planned escalation of the dose from 4, to 5 and 6 mg/m(2). Fourteen patients were enrolled in the study. The first dose of vinorelbine was 4 mg/m(2) and it showed to be feasible without dose-limiting toxicity (DLT). Instead, the second dose level of 5 mg/m(2) was unfeasible because three out of six patients had DLT (grade 4 neutropenia, treatment interruption longer than 2 weeks for prolonged grade 2 neutropenia and treatment interruption longer than 2 weeks for prolonged grade 3 esophagitis together with grade 4 dyspnea). At that time, the study continued adding amifostine to vinorelbine in order to increase its MTD. Amifostine was administered by means of subcutaneous injection 15 min before each radiotherapy fraction at the fixed dose of 300 mg/m(2). However, 5 mg/m(2) of vinorelbine were considered unfeasible even with amifostine support because three out of five patients showed DLT (grade 4 neutropenia, febrile grade 4 neutropenia and grade 3 liver toxicity). Among 14 patients enrolled in the study, eight completed the planned treatment because six patients experienced DLT, which determined treatment interruption. Overall, four partial and two complete responses were observed. Two partial and one complete response were observed in those three patients who had been treated with the first dose of vinorelbine. In conclusion, our data show that the MTD of daily vinorelbine is 4 mg/m(2). Therefore, this is the recommended dose of daily vinorelbine to be administered with concurrent thoracic radiotherapy in a phase II trial. Finally, amifostine administered subcutaneously failed to increase the MTD of daily vinorelbine.

Adenocarcinoma↗
PubMed2000

Amifostine plus cisplatin plus vinorelbine in the treatment of advanced non small cell lung cancer: a multicenter phase II study.

PURPOSE: to evaluate the activity and toxicity of the combination cisplatin plus vinorelbine plus amifostine in advanced non small cell lung cancer (NSCLC). PATIENTS AND METHODS: a two-stage Simon design was applied. To proceed after the first stage, responses from seven of 19 patients were needed. Overall, 17 responses from 40 treated patients were required to comply with the design parameter. Inclusion criteria were cyto-histologically proven stage IIIB-IV NSCLC; age of 70 years or less; Eastern Cooperative Oncology Group (ECOG) performance status of 2 or less; normal cardiac, hepatic, renal and bone marrow functions; and no previous chemotherapy. Patients were staged by physical examination, biochemistry, chest radiograph, brain, thoracic and abdominal computed tomographic (CT) scans, and bone scan. All patients received cisplatin 100 mg/m(2) intravenously (iv) day 1, vinorelbine 25 mg/m(2) iv days 1-8-15-22, amifostine 740 mg/m(2) iv day 1 every 4 weeks up to six cycles. Eleven of 40 enrolled patients were stage IIIB and 29 stage IV, with a median age of 57 years (range, 38-70 years). RESULTS: all patients were evaluable for response and toxicity (intention to treat analysis). We observed 20 (50%) objective responses, with four (10%) complete responses. Median time to progression was 20 weeks, and median survival was 45 weeks. The toxicity was manageable. The reported main toxicities were neutropenia grade 4 in 10% of patients, grade 1 and grade 3 nephrotoxicity both in 5% of patients and grade 1 amifostine-related hypotension in 15% of patients. CONCLUSION: these data show that cisplatin plus vinorelbine plus amifostine is an active and feaseable regimen in stage IIIB-IV NSCLC. A phase III trial comparing cisplatin plus vinorelbine versus cisplatin plus vinorelbine plus amifostine in advanced NSCLC is warranted.

Adult↗
PubMed2000

Cardiac compromise in a patient with Down's Syndrome: a lesson learnt.

A 49 year old burn victim with Down's Syndrome (Trisomy 21) was admitted with 15% body surface area (BSA) superficial burns. This was complicated by a large atrioseptal defect. Her course was stormy with difficulties encountered in managing her fluid status. Adequate fluid resuscitation was difficult to maintain with a fragile compromise between pulmonary insufficiency and renal impairment. She expired 12 days post-injury. Cardiac anomalies are not uncommon in the subgroup of patients with major burns who respond poorly to fluid resuscitation.

Acute Kidney Injury↗
PubMed2000

Natriuretic peptide levels in atrial fibrillation: a prospective hormonal and Doppler-echocardiographic study.

OBJECTIVES: The objective was to determine the independent association between atrial fibrillation (A-Fib) and activation of natriuretic peptides. BACKGROUND: The association of A-Fib with activation of N-terminal atrial and brain natriuretic peptides (N-ANPs and BNPs, respectively) is uncertain but of great importance for the diagnostic utilization of natriuretic peptides. This uncertainty is related to the lack of appropriate controls, with left ventricular (LV) and atrial overload similar to A-Fib. METHODS: We prospectively measured N-terminal atrial and BNPs and endothelin-1 levels in 100 patients and 14 age- and gender-matched control subjects. The 32 patients with A-Fib were compared with 68 patients in sinus rhythm and similar LV and atrial overload (due to mitral regurgitation or LV dysfunction) measured simultaneously with hormonal levels with comprehensive Doppler echocardiography. RESULTS: Patients with A-Fib compared with those in sinus rhythm had similar symptoms, comorbid conditions, cardioactive medications, pulmonary pressure, left atrial volume, and LV ejection fraction and filling characteristics but demonstrated higher N-ANP levels (2,613 +/- 1,681 vs. 1,654 +/- 1,323 pg/ml, p = 0.007) even after adjustment for the underlying cardiac disease (p < 0.0001). Conversely, BNP levels were similar in both groups (165 +/- 163 vs. 160 +/- 269 pg/ml, p = 0.9). In multivariate analysis, a higher N-ANP level was associated with A-Fib (p = 0.0003), symptom class (p < 0.0001) and endothelin-1 level (p = 0.032) independently of left atrial volume and LV ejection fraction. Conversely, BNP showed no independent association with and was most strongly associated with LV ejection fraction (p < 0.0001). CONCLUSIONS: Atrial fibrillation is an independent determinant of higher N-ANP levels and blurs its association with LV dysfunction. Conversely, the BNP is not independently associated with A-Fib and is strongly determined by LV dysfunction, for which it is an independent marker.

Aged↗
PubMed2000

Stability and networks of hydrogen bonds of the collagen triple helical structure: influence of pH and chaotropic nature of three anions.

The thermal stability of the trimeric species formed by seven type I collagen CNBr peptides was determined at neutral and acidic pH. Melting temperature of peptide trimers and free energy change for monomer to trimer transition were used as indices of trimer stability. A greater stability at neutral pH than at acidic pH was found for all peptides analysed because in most conditions an entropic gain overwhelms an enthalpic cost. Enthalpic reasons are prevailing only in some conditions of the more acidic peptides. The overlap zone of type I collagen fibrils is more basic than the gap zone and is therefore more sensitive to variations of pH from neutral to acidic, e.g. in bone degradation when osteoclasts acidify the lacuna lying between cell and bone. Peptide trimer stability in neutral conditions is influenced also by the chaotropic nature and the concentration of three anions: chloride, sulfate and phosphate. This was more evident for sulfate at the highest concentration used (0.5 M) when a greater stability is caused by entropic reasons. The contribution of hydroxyproline to the stability of peptide trimers is greater at neutral than at acidic pH, particularly at the highest concentration of sulfate. All our data indicate that pH, chaotropic nature and concentration of three anions influence the networks of hydrogen bonds present in the collagen triple helical structure.

Animals↗
PubMed2000

Synthesis and characterization of a cobalt(III) complex with 1-(D-3-mercapto-2-methylpropionyl)-L-proline.

The reaction of CoCl2 with 1-(D-3-mercapto-2-methylpropionyl)-L-proline (L or captopril) yields a new nanocrystalline complex with general formula [CoL2(OH)]2. The complex has been characterised with infrared (IR) and ultra-violet visible (UV-vis) spectroscopies, magnetic measurements, X-ray photoelectron spectroscopy (XPS), and wide angle X-ray scattering (WAXS). XPS analyses is a valuable tool for studying the chemical composition and the chemical state of elements at the surface of solids whereas WAXS provides information on the short range order. A model is proposed for the binding of the complex and its structure: the Co(III) ion is bonded with a pseudo-octahedral configuration. Captopril molecules are coordinated via mercapto group and amidic C=O group to Co(III) ions: two S atoms are bridging bonded between two Co(III) ions. The OH- ion completes the coordination around the Co(III).

Captopril↗
PubMed2000

A novel monoclonal antibody specific for lymphatic endothelium.

The difficulty of identifying and differentiating lymphatic and blood microvessels in tissue sections can be overcome by a monoclonal antibody specific for lymphatic endothelium. Unfortunately, the only known antibody also reacts with the endothelium of some blood vessels. The technique of double immunization (passive, with an antiserum to blood endothelium, and active, with a suspension of lymphatic endothelial cells) was, therefore, used to increase the chances of recognizing specific lymphatic antigens by the mouse immune system. The monoclonal antibody obtained, LyMAb, a G1 immunoglobulin, reacted strongly with the endothelium of bovine thoracic duct, mesenteric collecting vessels and lymphatic vessels of gallbladder and lymph nodes and moderately with those of the intestinal wall. Blood vessels (intercostal arteries, azygos vein and blood microvessels of all organs tested) were consistently negative. The antibody was species-specific and did not react with formalin-fixed, paraffin-embedded sections. Cross-reactivity was limited to some connective tissue fibres and scattered cells in the lymph node parenchyma, intestinal villi and hepatic lobules.

Animals↗