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Biomedical subjects

C Rossi

Publications and source records attributed to C Rossi.

At least 91 records · Page 5Linked to original sources
PubMed2000

Flavonoids apigenin and quercetin inhibit melanoma growth and metastatic potential.

Flavonoids are a class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including chemoprevention and tumor growth inhibition. Our aim was to investigate the effects of several polyphenols on the growth and metastatic potential of B16-BL6 melanoma cells in vivo. Intraperitoneal administration of quercetin, apigenin, (-)-epigallocathechin-3-gallate (EGCG), resveratrol, and the anti-estrogen tamoxifen, at the time of i.m. injection of B16-BL6 cells into syngeneic mice, resulted in a significant, dose-dependent delay of tumor growth, without toxicity. The relative descending order of potency was EGCG > apigenin = quercetin = tamoxifen > resveratrol > control. Furthermore, polyphenols significantly potentiated the inhibitory effect of a non-toxic dose of cisplatin. When tested for the ability to inhibit lung colonization, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the number of B16-BL6 colonies in the lungs in a dose-dependent manner, with quercetin and apigenin being more effective than tamoxifen. Interestingly, quercetin, apigenin, and tamoxifen (but not EGCG or resveratrol) significantly decreased the invasion of B16-BL6 cells in vitro, with quercetin and apigenin being more effective than tamoxifen. This suggests that anti-invasive activity is one of the mechanisms underlying inhibition of lung colonization by quercetin and apigenin. In conclusion, quercetin and apigenin inhibit melanoma growth and invasive and metastatic potential; therefore, they may constitute a valuable tool in the combination therapy of metastatic melanoma.

Animals↗
PubMed2000

Liposome-based formulations for the antibiotic nonapeptide Leucinostatin A: Fourier transform infrared spectroscopy characterization and in vivo toxicologic study.

Leucinostatin-A is a nonapeptide isolated from Paecilomyces marquandii, Paecilomyces lilacinus A257, and Acremonium sp., exerting remarkable phytotoxic, antibacterial (especially against Gram-positive) and antimycotic activities. With the aim to find alternative formulation for in vivo administration, a number of Leucinostatin-A-loaded liposomal formulations have been prepared and characterized. Both large unilamellar vesicles and multilamellar vesicles consisting of synthetic and natural lipids were evaluated. In addition, to determine the nature of peptide-membrane interactions and the stability of liposomes loaded with Leucinostatin-A, a Fourier Transform Infrared Spectroscopy study was performed. The results suggest that the mode of interaction of the peptide is dependent on its concentration, on bilayer fluidity, and on liposome type. Finally, the LD50 of both free and liposome-delivered Leucinostatin-A was determined in mice. These results suggest that the incorporation of Leucinostatin-A into liposomes may result in decreased Leucinostatin-A toxicity, as the intraperitoneal administration of Leucinostatin-A-loaded liposomes reduced the LD50 of Leucinostatin-A 15-fold.

Animals↗
PubMed2000

IDN5109, a taxane with oral bioavailability and potent antitumor activity.

IDN5109 is a new taxane, derived from 14beta-hydroxy-10-deacetylbaccatin III, selected for its lack of cross-resistance in tumor cell lines expressing the multidrug resistant phenotype. Because, unlike paclitaxel, IDN5109 is a poor substrate for P-glycoprotein, we hypothesized that IDN5109 given p.o. could improve bioavailability compared with paclitaxel. Here, we studied the p.o. and i.v. pharmacokinetics of IDN5109 together with its antitumor activity. Using a high-performance liquid chromatography method, the bioavailability of IDN5109 was determined to be 48% after oral delivery. IDN5109 given p.o. was highly active against the two human ovarian carcinoma xenografts 1A9 and HOC18 (90-100% tumor regressions) and showed significant activity on the paclitaxel-resistant MNB-PTX1 xenograft (10% tumor regressions). The p.o. administration was as active as the i.v. route at doses reflecting the pharmacokinetic data. IDN5109 is the first taxane with good oral bioavailability and potent antitumor activity and represents a potential candidate for clinical investigation.

Administration, Oral↗
PubMed2000

First trimester biochemical screening for Down syndrome: free beta hCG versus intact hCG.

To compare free beta hCG versus intact hCG in first trimester Down syndrome screening we analysed 63 cases of Down syndrome and 400 unaffected control pregnancies between 10 and 13 weeks' gestation. The Down syndrome median multiple of the median (MoM) was significantly higher (p=0.001) for free beta hCG (1.89 MoM) than for intact hCG (1.37 MoM). Although distributions for free beta hCG (unaffected, 0.2157; DS, 0.2322) are wider than for intact hCG (unaffected, 0.1697; DS, 0.2158), overall 27% of Down syndrome cases were above the 95th percentile for free beta hCG compared to 19% for intact hCG. Combined with maternal age, free beta hCG detected 45% of Down syndrome pregnancies at a 5% false positive rate. Intact hCG combined with maternal age demonstrated a detection efficiency comparable to maternal age alone (35% versus 32%). In contrast, a recent study (Haddow et al., 1998-NEJM 338: 955-961) indicated that intact hCG yielded a higher first trimester Down syndrome detection efficiency than free beta hCG (29% versus 25% respectively). Re-analysis of distribution parameters in the Haddow et al. study, however, show that free beta hCG was actually the better marker (23% detection for intact hCG versus 29% for free beta hCG).

Adult↗
PubMed2000

Ommaya-catheter-related Staphylococcus epidermidis cerebritis and recurrent bacteremia documented by molecular typing.

A 26-year-old woman receiving intrathecal chemotherapy for acute leukemia developed Ommaya-catheter-associated cerebritis and bacteremia caused by two clones of Staphylococcus epidermidis. Genomic fingerprinting of 19 staphylococcal isolates from the cerebrospinal fluid, blood, catheter and skull biopsy was necessary to establish the etiologic diagnosis and to guide medical and surgical therapy.

Adult↗
PubMed2000

Identification of different forms of calpastatin mRNA co-expressed in the notochord of Xenopus laevis embryos.

We isolated three Xenopus cDNA clones, Xcalp1, Xcalp2 and Xcalp3, which encode different forms of calpastatin mRNA. Compared to the canonical form of mammalian calpastatin, the predicted Xcalp3 protein contained a very long N-terminal domain L and an additional inhibitory domain. The other two deduced calpastatin proteins were truncated forms, both lacking domain L and containing four (Xcalp2) and two (Xcalp1) inhibitory domains, respectively. The presence of Xcalp1, Xcalp2 and Xcalp3 transcripts was detected by in situ hybridization in the notochord from the embryonic stage 20 to stage 36, afterwards the expression was only present in the growing tailbud. As shown by RT-PCR, the three calpastatin mRNAs were also expressed in the adult brain.

Amino Acid Sequence↗
PubMed2000

Hysteroscopic evaluation of menopausal women with endometrial thickness of 4 mm or more.

STUDY OBJECTIVE: To assess the diagnostic and operative potential of hysteroscopy in postmenopausal patients selected by ultrasound criteria. DESIGN: Cohort study (Canadian Task Force classification II-2). SETTING: Outpatient ultrasound and hysteroscopy department of a university-affiliated hospital. PATIENTS: One hundred fifty-five postmenopausal women with endometrial thickness of 4 mm or more by ultrasound, in menopause for at least 1 year, with or without menopausal complaints. INTERVENTIONS: Transvaginal ultrasound and office hysteroscopy with eye-directed biopsy specimens using a 5-mm, continuous-flow, operative hysteroscope. MEASUREMENTS AND MAIN RESULTS: Of the 155 women, 129 (83%) were asymptomatic (irregular bleeding). Hysteroscopy showed endometrial pathology in 28% of asymptomatic patients (23 polyps, 5 cases of hyperplasia, 8 submucous myomata) and 76% of symptomatic women (13 polyps, 6 hyperplasia, 1 submucous myoma). Hysteroscopic results compared with histologic diagnosis showed a positive predictive value equal to 97. 1% and 95% in asymptomatic and symptomatic women, respectively, and a negative predictive value equal to 100% in both groups. CONCLUSION: Office hysteroscopy with endometrial biopsy samples has a diagnostic and operative role in postmenopausal patients selected based on endometrial thickness on ultrasound, in view of the high prevalence of endometrial pathology in both symptomatic and asymptomatic women.

Adult↗
PubMed2000

Amifostine (WR-2721) selective protection against melphalan genotoxicity.

Amifostine (WR-2721) is an aminothiol compound dephosphorylated at the tissue site by alkaline phosphatase to the active metabolite, which is able to inactivate electrophilic substances and scavenge free radicals. Amifostine effects against melphalan-induced DNA strand breaks were studied in normal human white blood cells (WBC) and K562 leukemic cells using the single cell gel electrophoresis (SCGE) or Comet assay, a reported method for measuring DNA damage in individual cells. Prior to treatment (1 h, 37 degrees C) with increasing doses of melphalan, with or without S9, the cells were treated (15 min, 37 degrees C) with a control medium or amifostine (3 mg/ml). Treatment of normal and leukemic cells with melphalan induced a dose-dependent 'comet formation'. Melphalan-induced DNA damage follows a normal distribution in WBC. On the other hand, in K562, a significant proportion of undamaged cells remains even with doses at which mean DNA damage is serious. Pretreatment with WR-2721 protects WBC, but not K562, against the genotoxic effect of melphalan. Amifostine might even strengthen the action of the antiblastic drug against K562 cells. S9 addition appears to enhance melphalan effectiveness. SCGE appears as a suitable primary screening method for in vitro and in vivo studies on drug-DNA interactions and their modulations by endogenous/exogenous factors.

Amifostine↗
PubMed2000

A novel interpretation of the role of von Willebrand factor in thrombotic microangiopathies based on platelet adhesion studies at high shear rate flow.

Clinical manifestations of thrombotic microangiopathies (TMA) are secondary to platelet aggregation and thrombotic occlusion of the microvasculature of the affected organs. Abnormalities in von Willebrand factor (vWF) in these patients were considered instrumental in promoting the process leading to microvascular thrombosis. We evaluated the capacity of plasma in these patients to induce adhesion of normal platelets and thrombus formation under conditions of controlled fluid shear stress. We also studied vWF multimeric distribution to establish whether abnormalities of this glycoprotein correlate with platelet adhesion and thrombus formation. Plasma from patients in the acute phase and remission showed the same capacity to induce platelet adhesion and thrombus formation at a low level of shear rate (600 sec(-1)) as plasma from control subjects. At a high shear rate (1,500 sec(-1)), platelet adhesion and thrombus dimensions were significantly increased (P: < 0.05) by plasma from patients with TMA compared with controls. The capacity to enhance thrombus formation at high shear stress was present during the acute phase and disease remission and did not correlate with the presence of unusually large vWF multimers. Increased thrombus formation with patient plasma is completely normalized by blocking the interaction of vWF with the platelet receptors, glycoprotein (GP)Ib and GPIIb-IIIa, suggesting that the phenomenon is completely mediated by vWF. Our results suggest the possibility of an intrinsically altered vWF molecule in these patients that is probably more effective than normal vWF in mediating platelet adhesion and thrombus formation.

Adult↗
PubMed2000

Homologous and heterologous glycoproteins induce protection against Junin virus challenge in guinea pigs.

Tacaribe virus (TACV) is an arenavirus that is genetically and antigenically closely related to Junin virus (JUNV), the aetiological agent of Argentine haemorrhagic fever (AHF). It is well established that TACV protects experimental animals fully against an otherwise lethal challenge with JUNV. To gain information on the nature of the antigens involved in cross-protection, recombinant vaccinia viruses were constructed that express the glycoprotein precursor (VV-GTac) or the nucleocapsid protein (VV-N) of TACV. TACV proteins expressed by vaccinia virus were indistinguishable from authentic virus proteins by gel electrophoresis. Guinea pigs inoculated with VV-GTac or VV-N elicited antibodies that immunoprecipitated authentic TACV proteins. Antibodies generated by VV-GTac neutralized TACV infectivity. Levels of antibodies after priming and boosting with recombinant vaccinia virus were comparable to those elicited in TACV infection. To evaluate the ability of recombinant vaccinia virus to protect against experimental AHF, guinea pigs were challenged with lethal doses of JUNV. Fifty per cent of the animals immunized with VV-GTac survived, whereas all animals inoculated with VV-N or vaccinia virus died. Having established that the heterologous glycoprotein protects against JUNV challenge, a recombinant vaccinia virus was constructed that expresses JUNV glycoprotein precursor (VV-GJun). The size and reactivity to monoclonal antibodies of the vaccinia virus-expressed and authentic JUNV glycoproteins were indistinguishable. Seventy-two per cent of the animals inoculated with two doses of VV-GJun survived lethal JUNV challenge. Protection with either VV-GJun or VV-GTac occurred in the presence of low or undetectable levels of neutralizing antibodies to JUNV.

Animals↗
PubMed2000

Comparison of two rapid diagnostic assays for detection of immunoglobulin M antibodies to dengue virus.

Two easy-to-use commercial diagnostic assays, a dipstick enzyme-linked immunosorbent assay (ELISA) (Integrated Diagnostics, Baltimore, Md.) and an immunochromatographic card assay (PanBio, Brisbane, Australia) were evaluated for detection of immunoglobulin M (IgM) antibody to dengue virus with an in-house IgM antibody capture microplate ELISA as a reference assay. The dipstick ELISA was based on the indirect-ELISA format using dengue 2 virus as the only antigen and enzyme-labeled goat anti-human IgM antibody as the detector. The total assay time was 75 min. The immunochromatographic card assay was based on the antibody capture format and separately measured both anti-dengue virus IgM and IgG in the same test. Colloidal-gold-labeled anti-dengue virus monoclonal antibody bound with dengue virus 1 to 4 antigen cocktail was the detector, and anti-human IgM and IgG were the capture antibodies. The total assay time was <10 min. Sera from 164 individuals classified as either anti-dengue virus IgM positive (94) or anti-dengue virus IgM negative (70) in the reference microplate ELISA with a dengue virus 1 to 4 antigen cocktail were tested in the two commercial assays. The dipstick ELISA missed 7 of 94 positive samples, for a sensitivity of 92.6%, while the immunochromatographic card assay missed two positive samples, for a sensitivity of 97.9%. Of the 70 negative samples, four were false positive by the dipstick ELISA and two were false positive in the immunochromatographic card assay, resulting in specificities of 94.3 and 97.1%, respectively. Both commercial assays provide sensitive and specific detection of anti-dengue virus IgM antibody and could prove useful in settings where the microplate ELISA is impractical.

Antibodies, Monoclonal↗
PubMed2000

Evaluation of immunoglobulin M (IgM) and IgG enzyme immunoassays in serologic diagnosis of West Nile Virus infection.

A unique urban encephalitis epidemic in Romania signaled the emergence of neurological infection due to West Nile (WN) virus as a novel public health threat in Eastern Europe and provided an opportunity to evaluate patterns of immunoglobulin G (IgG) and IgM reactivity in IgM capture and IgG enzyme-linked immunosorbent assays (ELISAs). WN virus infection was diagnosed serologically in 236 of 290 patients from whom acute serum or cerebrospinal fluid (CSF) samples were available. In 37% of serum samples and in 25% of CSF samples collected in the first week of illness, anti-WN virus IgM antibody was detected in the absence of virus-specific IgG. The switch to an IgG antibody response occurred after 4 to 5 days of illness and earlier in CSF than in serum. A specific humoral immune response was detected in the CSF before the serum in some patients for whom paired CSF and serum samples from the same day were available. IgM antibody in convalescent serum samples persisted beyond 2 months after the onset of illness in more than 50% of patients. ELISA optical density values and antibody concentrations were well correlated for both IgM and IgG immunoassays. Anti-WN virus IgM antibody in acute-phase samples did not cross-react significantly with flaviviruses in other antigenic groups.

Antibodies, Viral↗
PubMed2000

Essential thrombocythemia in young adults: major thrombotic complications and complications during pregnancy--a follow-up study in 68 patients.

OBJECTIVES: Although essential thrombocythemia (ET) is usually primarily considered a disorder of middle age, it has been observed in children and young adults. However, the real risk for thrombosis in these patients has not been clearly established. DESIGN: Prospective analysis of consecutive patients younger than 40 at the time of the diagnosis of ET and followed in our department between 1980 and 1998. SUBJECTS: Sixty-eight patients (28 males and 40 females, median follow-up 99.14 months) affected by ET diagnosed in agreement with the Polycythemia Vera Study Group criteria. INTERVENTIONS: Asymptomatic ET patients were not treated. In contrast, patients with associated atherosclerotic risk factors, microvascular disturbances, or a previous major arterial thrombosis were given acetyl salicylic acid (ASA 100 mg/day). Only patients with major thrombotic complications and a platelet count > 1,000 x 10(9)/L received cytoreductive therapy. OUTCOME MEASURES: (1) to evaluate thrombotic complications in young patients with ET, (2) to relate thrombotic risk to the presence of general atherosclerotic risk factors, and (3) to adopt treatment, and (4) to report the outcome of the pregnancies monitored in our population. RESULTS: Fifteen patients had major thrombosis, 11 of which were the presenting features of ET. No rethrombosis has been observed. Only one patient with thrombotic complications was under efficient treatment. Atherosclerotic risk factors are more common in patients with major arterial thrombosis than in asymptomatic subjects. Thirteen normal babies were delivered out of 16 pregnancies, 6 of the pregnant women were on ASA therapy. CONCLUSIONS: Most thrombosis in young ET patients occurred at the time of the diagnosis, and venous thrombotic events represent one-third of total thrombosis. Cardiovascular risk factors seem to be concurrent stimuli for arterial thrombosis in ET. The thrombotic complication rate was 2.6/100 patients/year ASA reduces microvascular disturbances, thrombosis, and rethrombosis and possibly reduces obstetric complications in women with ET.

Acute Disease↗
PubMed2000

Choice of cesarean section and perception of legal pressure.

OBJECTIVE: To evaluate the perception of "Defensive Medicine" by hospital based obstetricians and the influence of this attitude on the choice of cesarean delivery. SUBJECTS AND METHODS: Questionnaire sent by mail to a sample (76) of obstetricians of general district, teaching and university hospitals in a region of southern Italy (Puglia). Doctors were selected as the head, the most senior and the most junior specialist of each department. Independent variables of the study were considered as demographic data of the subjects, years of service, interest in private practice, size of the hospital, background cesarean section rate, personal and site of work exposure to legal claims. Outcome measures were experience and confidence in training for operative vaginal and breech delivery, use of the partogram in labor, opinion about a trial of labor after a previous cesarean section and about cesarean section on request, personal perception of defensive medicine. Univariate and multivariate analysis of data were performed. RESULTS: The response rate was 83%. According to our data, seniority in service meant confidence in and request of more teaching of obstetrics manoeuvres, size of hospitals was positively related to a more rationale approach of the diagnosis of dystocia, heads of units were keener to accept the patient's wish for a cesarean section. Doctors with large private practices were less likely to be sued and the perception of legal pressure was directly related to the rate of cesarean section in each unit. DISCUSSION: Defensive Medicine is a reality that encompasses all categories of doctors in this survey. The only differences were in the rate of perception of legal pressure. We believe that residential programs should be modified in order to improve specialists' understanding of malpractice problems and that the patient-doctor relationship should be ameliorated in public hospitals.

Adult↗
PubMed2000

Expression of vascular endothelial growth factor can predict event-free survival in stage II colon cancer.

The usefulness of chemotherapy in patients with stage II disease continues to be debated. Biological prognostic factors may allow further insight into the optimal treatment strategy for patients with node-negative disease. Vascular endothelial growth factor (VEGF) seems to be essential for angiogenesis and for the growth of colorectal cancer. Recently, it was shown able to predict disease recurrence in patients with stage II colon cancer. Specimens of surgically resected colon cancer were immunostained for VEGF. Consecutive patients referred to the study institutions were considered eligible for this study. The main inclusion criteria were stage II tumor, sufficient tumor material, and adequate follow-up information. Analysis was performed on 121 patients. The recurrence rate in the patients with VEGF-positive tumors was 50% (18 of 36 patients), which was significantly higher than that observed in patients with VEGF-negative tumors [11.7% (10 of 85 patients); P = 0.001]. Also the degree of VEGF immunoreactivity was significantly higher in 28 relapsing patients compared with 93 disease-free patients (mean VEGF score, 2.84 0.38 versus 0.66 +/- 0.17; P = 0.0001). VEGF may be used in a clinical setting to identify patients at high risk for relapse who may benefit from adjuvant treatment including new therapeutic strategies such as monoclonal antibody neutralizing VEGF.

Adult↗
PubMed2000

[Prosthesis-related infections].

Long-term prosthetic devices are rapidly recovered by host proteins which increase bacterial adhesion. The bacteria can also produce extracellular polysaccharide material, which in combination of host proteins, produce a biofilm. This one decreases the host defense mechanisms, antibiotics penetration and efficacy, increasing infectivity of the pathogens. Most often, the device is contaminated in the perioperative period by commensal flora. It can also be infected by hematogenous seeding or by contiguous infection. Various clinical presentations of infected devices are described depending on the type of prosthesis, its anatomical localisation and the time elapsed since insertion. Postoperative acute sepsis, insidious infectious signs or isolated device malfunction without signs of infection have all been described. The prosthetic infection rate is low, but when it occurs, the consequences are catastrophic. Excepted in some selected cases, the classical treatment combines the removal of the prosthesis and a long-term appropriate antibiotic therapy. If infection is suspected, it's crucial to establish the diagnosis accurately often by using invasive diagnostic methods (CT-scan guided biopsy, etc.) to obtain adequate samples which detailed microbiological analysis should be carefully interpreted.

Bacterial Adhesion↗