Biomedical subjects

Alessandro Riva

Publications and source records attributed to Alessandro Riva.

16 recordsLinked to original sources

PubMed2006

Structure of cristae in cardiac mitochondria of aged rat.

Interfibrillar mitochondria (IFM) of the heart in aged Fischer 344 rats show a biochemical defect which might be reflected in their morphology. We examined by high resolution scanning electron microscopy over 5500 mitochondria to determine if a concomitant structural alteration existed. This methodology provides a means of examining mitochondrial cristae in three dimensions. Cristae of in situ subsarcolemmal mitochondria (SSM) and of IFM in both 6- and 24-month-old Fischer rats are predominantly lamelliform. When isolated, these organelles, whether of SSM or IFM origin, display enhanced heterogeneity, but they have similar crista morphology irrespective of the age of the rat. Crista configuration does not play a major role in age-related cardiac mitochondrial defects.

Aging↗

PubMed2006

Cytomorphological study on human submandibular gland following treatment with secretagogue drugs.

Using specimens of human submandibular glands, we have investigated in vitro the morphological modifications induced by clozapine, a dibenzodiazepine derivative that is used in psychotic patients and that provokes hypersalivation, a side-effect of therapy. The effects of the drug, used alone or in combination with carbachol, have been compared with those observed after treatment with drugs acting on specific receptors. To quantify the response to stimulation, we have calculated (with statistical methods) the number of microvilli and microbuds (corresponding to pits seen in images obtained by transmission electron microscopy) per square micrometre of the cytoplasmic surface of the intercellular canaliculi luminal membrane in images obtained by high-resolution scanning electron microscopy. Clozapine, when directly acting on human submandibular specimens, induces a small secretory response in serous cells; this is partially decreased by muscarinic and adrenergic antagonists and by combined incubation with carbachol, thus confirming its behaviour as a partial agonist to muscarinic receptors. We also suggests that the drug acts on the nerve terminals contained within the glandular specimens.

Adult↗

PubMed2005

Diagnostic evaluation of HER-2 as a molecular target: an assessment of accuracy and reproducibility of laboratory testing in large, prospective, randomized clinical trials.

PURPOSE: To critically assess the accuracy and reproducibility of human epidermal growth factor receptor type 2 (HER-2) testing in outside/local community-based hospitals versus two centralized reference laboratories and its effect on selection of women for trastuzumab (Herceptin)-based clinical trials. EXPERIMENTAL DESIGN: Breast cancer specimens from 2,600 women were prospectively evaluated by fluorescence in situ hybridization (FISH) for entry into Breast Cancer International Research Group (BCIRG) clinical trials for HER-2-directed therapies. RESULTS: HER-2 gene amplification by FISH was observed in 657 of the 2,502 (26%) breast cancers successfully analyzed. Among 2,243 breast cancers with central laboratory immunohistochemistry (10H8-IHC) analysis, 504 (22.54%) showed overexpression (2+ or 3+). Outside/local laboratories assessed HER-2 status by immunohistochemistry in 1,536 of these cases and by FISH in 131 cases. Overall, the HER-2 alteration status determined by outside/local immunohistochemistry showed a 79% agreement rate [kappa statistic, 0.56; 95% confidence interval (95% CI), 0.52-0.60], with FISH done by the central laboratories. The agreement rate comparing BCIRG central laboratory 10H8-IHC and outside/local laboratory immunohistochemistry was 77.5% (kappa statistic, 0.51; 95% CI, 0.46-0.55). Finally, HER-2 status, determined by unspecified FISH assay methods at outside/local laboratories, showed a 92% agreement rate (kappa statistic, 0.83; 95% CI, 0.73-0.93), with FISH done at the BCIRG central laboratories. CONCLUSIONS: Compared with the HER-2 status determined at centralized BCIRG reference laboratories, these results indicate superiority of FISH to accurately and reproducibly assess tumors for the HER-2 alteration at outside/local laboratories for entry to clinical trials.

Biomarkers, Tumor↗

PubMed2005

Adjuvant docetaxel for node-positive breast cancer.

BACKGROUND: We compared docetaxel plus doxorubicin and cyclophosphamide (TAC) with fluorouracil plus doxorubicin and cyclophosphamide (FAC) as adjuvant chemotherapy for operable node-positive breast cancer. METHODS: We randomly assigned 1491 women with axillary node-positive breast cancer to six cycles of treatment with either TAC or FAC as adjuvant chemotherapy after surgery. The primary end point was disease-free survival. RESULTS: At a median follow-up of 55 months, the estimated rates of disease-free survival at five years were 75 percent among the 745 patients randomly assigned to receive TAC and 68 percent among the 746 randomly assigned to receive FAC, representing a 28 percent reduction in the risk of relapse (P=0.001) in the TAC group. The estimated rates of overall survival at five years were 87 percent and 81 percent, respectively. Treatment with TAC resulted in a 30 percent reduction in the risk of death (P=0.008). The incidence of grade 3 or 4 neutropenia was 65.5 percent in the TAC group and 49.3 percent in the FAC group (P<0.001); rates of febrile neutropenia were 24.7 percent and 2.5 percent, respectively (P<0.001). Grade 3 or 4 infections occurred in 3.9 percent of the patients who received TAC and 2.2 percent of those who received FAC (P=0.05); no deaths occurred as a result of infection. Two patients in each group died during treatment. Congestive heart failure and acute myeloid leukemia occurred in less than 2 percent of the patients in each group. Quality-of-life scores decreased during chemotherapy but returned to baseline levels after treatment. CONCLUSIONS: Adjuvant chemotherapy with TAC, as compared with FAC, significantly improves the rates of disease-free and overall survival among women with operable node-positive breast cancer.

Adult↗

PubMed2005

In vitro activity of amphibian peptides alone and in combination with antimicrobial agents against multidrug-resistant pathogens isolated from surgical wound infection.

The in vitro activities of three amphibian peptides magainin II amide, citropin 1.1 and temporin A alone and in combination with eight clinically used antimicrobial agents (imipenem, ceftazidime, clarithromycin, vancomycin, amikacin, polymyxin E, ciprofloxacin and linezolid) were investigated against several multidrug-resistant Pseudomonas aeruginosa and Staphylococcus aureus strains isolated from surgical wound infections. Antimicrobial activities were measured by MIC, MBC and time-kill studies. P. aeruginosa strains were more susceptible to magainin II amide and less susceptible to temporin A. S. aureus isolates were highly susceptible to temporin A and citropin 1.1. The combination studies showed synergy between citropin 1.1 and clarithromycin. Magainin II amide and temporin A showed synergism with imipenem and ceftazidime. Finally, all peptides showed synergistic effects with polymyxin E. These results provide evidence for the potential use of these antimicrobial peptides in the topical or systemic treatment of surgical wound infections.

Amphibian Proteins↗

PubMed2005

Structural differences in two biochemically defined populations of cardiac mitochondria.

To determine whether there are structural differences in two topologically separated, biochemically defined mitochondrial populations in rat heart myocytes, the interior of these organelles was examined by high-resolution scanning electron microscopy. On the basis of a count of 159 in situ subsarcolemmal mitochondria (SSM, i.e., those that directly abut the sarcolemma), these organelles possess mainly lamelliform cristae (77%), whereas the cristae in in situ interfibrillar mitochondria (IFM, i.e., those situated between the myofibrils, n = 300) are mainly tubular (55%) or a mixture of tubular and lamelliform (24%). Isolated SSM (n = 374), similar to their in situ counterparts, have predominantly lamelliform cristae (75%). The proportions of crista types in isolated IFM (n = 337) have been altered, with only 20% of these organelles retaining exclusively tubular cristae, whereas 58% are mixed; of the latter, lamelliform cristae predominate. This finding suggests that, in contrast to SSM, the cristae in IFM are structurally plastic, changing during isolation. These observations on >1,000 organelles provide the first quantitative morphological evidence for definitive differences between the two populations of cardiac mitochondria.

Animals↗

PubMed2004

Results of two open-label, multicenter phase II studies of docetaxel, platinum salts, and trastuzumab in HER2-positive advanced breast cancer.

BACKGROUND: Preclinical data indicate that docetaxel, platinum salts, and the combination of both drugs are highly synergistic with the anti-HER2 antibody trastuzumab. The University of California at Los Angeles-Oncology Research Network (UCLA-ORN) and the Breast Cancer International Research Group (BCIRG) have conducted two phase II studies to evaluate docetaxel and trastuzumab in combination with either cisplatin or carboplatin for the treatment of women with advanced breast cancer that overexpresses HER2. METHODS: Each study enrolled 62 patients with HER2-overexpressing tumors. Patients received a median of six cycles of docetaxel at 75 mg/m2 of body surface area and cisplatin (BCIRG 101 study) at 75 mg/m2 or carboplatin (UCLA-ORN study) at AUC = 6 mg/mL. min given on day 1 and then every 21 days. Trastuzumab was given on day 1, cycle 1 (4 mg/kg) and then continued weekly at 2 mg/kg for 1 year or until disease progression. Tumor measurements were obtained at baseline, after three cycles of chemotherapy, and then every 3 months. HER2 gene amplification was determined by fluorescence in situ hybridization. RESULTS: Patient characteristics were comparable between trials with the exception that 15% of the patients in the UCLA-ORN study had received previous adjuvant taxane therapy. Both regimens were well tolerated, with manageable toxicities. Hematologic toxicities were more frequent in patients in the UCLA-ORN study than in patients in the BCIRG 101 study, whereas the reverse pattern was observed for non-hematologic toxicities. One patient in each study developed reversible congestive heart failure. Responses were observed in 49 of 62 patients in the BCIRG 101 study (overall response rate = 79%, 95% confidence interval [CI] = 66% to 89%) and in 34 of 59 evaluable patients in the UCLA-ORN study (overall response rate = 58%, 95% CI = 44% to 70%). Median times to progression were 9.9 months (95% CI = 8.3 to 13.1 months) and 12.7 months (95% CI = 8.6 to 15.5 months) for patients in the BCIRG 101 and UCLA-ORN studies, respectively. Overall response rates were higher and median time to progression was longer in the subset of patients whose tumors harbored HER2 gene amplification. CONCLUSION: Combinations of docetaxel, a platinum salt, and trastuzumab are feasible and active in patients with advanced breast cancers that overexpress HER2. The BCIRG is conducting ongoing randomized studies of the three-drug combination in both the metastatic and adjuvant settings.

Adult↗

PubMed2004

Future options with trastuzumab for primary systemic and adjuvant therapy.

HER2 positivity can be detected early in breast cancer development and is associated with a poor outcome. Primary systemic therapy with trastuzumab (Herceptin; F. Hoffmann-La Roche, Basel, Switzerland) in combination with taxanes and other cytotoxic agents has been studied in phase II clinical trials in women with HER2-positive breast cancer. These combinations have achieved pathologic complete response rates of 12% to 42% and clinical complete response rates of 30% to 67%. These results compare favorably with those of primary systemic therapy using standard combinations in patients with unselected (HER2-positive or -negative) breast cancer. Consequently, larger studies are in progress in which trastuzumab is administered before surgery in combination with chemotherapy. Trastuzumab is continued as monotherapy afterward to complete 1 year of treatment or until disease progression. These studies aim to provide further proof of the clinical benefits associated with trastuzumab as primary systemic therapy. They will also investigate the molecular determinants of sensitivity and resistance. In addition, four major randomized trials, in more than 13,500 patients, are investigating the impact of adding trastuzumab to standard adjuvant therapy. Planned interim cardiac safety analyses have been passed without concerns. Recruitment to these studies has either recently been completed or continues as planned. Together, this extensive program, which includes analysis of predictive molecular and pathologic makers, will establish the efficacy, safety, and role of trastuzumab in early breast cancer.

Antibodies, Monoclonal↗

PubMed2003

Junctional complex revisited by high-resolution scanning electron microscopy.

The present study correlates the ultrastructural morphology of junctional complexes as revealed by transmission electron microscopy (TEM) with that observed by high-resolution scanning electron microscopy (HRSEM), thanks to a new modification of the osmium tetroxide maceration technique. The removal of all cytoplasmic organelles by this technique allows the inspection of the inner side of the plasmalemma. With this treatment, a continuous band of tightly packed particles is observed at the most apical portion of lateral membranes. Just below this band, irregular clusters of apparently identical particles are placed all around the cellular contour. The topographical correspondence among these clusters and spot desmosomes seen by TEM identifies them as desmosomes. The continuous band seems to represent the combination of both zonulae, occludens and adherens. Regarding the nature of the particles, we suppose that they probably consist of peripheral membrane proteins clustered at the cytoplasmic surface of intercellular junctions and involved in the linkage between cytoskeleton and plasmalemma.

Adolescent↗

PubMed2003

Docetaxel and doxorubicin compared with doxorubicin and cyclophosphamide as first-line chemotherapy for metastatic breast cancer: results of a randomized, multicenter, phase III trial.

PURPOSE: This randomized, multicenter, phase III study compared doxorubicin and docetaxel (AT) with doxorubicin and cyclophosphamide (AC) as first-line chemotherapy (CT) in metastatic breast cancer (MBC). PATIENTS AND METHODS: Patients (n = 429) were randomly assigned to receive doxorubicin 50 mg/m(2) plus docetaxel 75 mg/m(2) (n = 214) or doxorubicin 60 mg/m(2) plus cyclophosphamide 600 mg/m(2) (n = 215) on day 1, every 3 weeks for up to eight cycles. RESULTS: Time to progression (TTP; primary end point) and time to treatment failure (TTF) were significantly longer with AT than AC (median TTP, 37.3 v 31.9 weeks; log-rank P =.014; median TTF, 25.6 v 23.7 weeks; log-rank P =.048). The overall response rate (ORR) was significantly greater for patients taking AT (59%, with 10% complete response [CR], 49% partial response [PR]) than for those taking AC (47%, with 7% CR, 39% PR) (P =.009). The ORR was also higher with AT in patients with visceral involvement (58% v 41%; liver, 62% v 42%; lung, 58% v 35%), three or more organs involved (59% v 40%), or prior adjuvant CT (53% v 41%). Overall survival (OS) was comparable in both arms. Grade 3/4 neutropenia was frequent in both groups, although febrile neutropenia and infections were more frequent for patients taking AT (respectively, 33% v 10%, P <.001; 8% v 2%, P =.01). Severe nonhematologic toxicity was infrequent in both groups, including grade 3/4 cardiac events (AT, 3%; AC, 4%). CONCLUSION: AT significantly improves TTP and ORR compared with AC in patients with MBC, but there is no difference in OS. AT represents a valid option for the treatment of MBC.

Adult↗

PubMed2003

Mitochondria of human adrenal cortex have tubular cristae with bulbous tips.

By taking advantage of a modified osmium maceration technique, we have been able to examine by high resolution scanning electron microscopy (HRSEM) the interior of human adrenocortical mitochondria from which all soluble material has been extracted. The so-called vesicles apparent in thin sections examined by transmission electron microscopy actually are finger-like cristae as determined by HRSEM. These digitiform cristae have a segmented appearance and a bulbous tip. The segmented form of the cristae may have important metabolic implications.

Adrenal Cortex↗

PubMed2002

Evidence for the use of chemotherapy in breast cancer.

Several distinct historical phases mark the evolution of chemotherapy for breast cancer, including the introduction of single agents in the 1960s, the development of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF)-based regimens in the 1970s, the evaluation of the anthracyclines in the 1980s, and the incorporation of the taxanes in the 1990s. The greatest benefit from the use of standard combination chemotherapy occurs in the adjuvant setting, where absolute improvements in overall survival on the order of 10% have been achieved. In contrast, advances have been more modest in the treatment of metastatic disease, and novel agents and regimens are required for further progress. Of the new cytotoxic drugs introduced in the past decade, the taxanes and capecitabine appear to be the most promising, and have demonstrated activity alone and in combination for the treatment of metastatic disease. The introduction of trastuzumab, an antibody directed against the HER2 receptor protein, heralded the birth of targeted molecular therapy against breast cancer. It is clear that in the near future the further evaluation of trastuzumab combinations and the development of additional molecular agents will propel clinical breast cancer research. One of the main challenges of the new era will be identifying and validating predictive factors so that therapy may be individualized based on tumor biology, rather than empirically selected.

Biomarkers, Tumor↗

PubMed2002

Docetaxel in the treatment of breast cancer: an update on recent studies.

Recently there has been great interest in developing combination regimens involving taxanes and anthracyclines for the treatment of advanced breast cancer. Docetaxel in particular has substantial activity when combined with doxorubicin. In one randomized trial, the combination of doxorubicin 50 mg/m(2) and docetaxel 75 mg/m(2) showed significantly greater activity than doxorubicin plus cyclophosphamide (AC), producing a higher response rate (60% v 47%) and longer time to progression. In a second study, 484 patients were randomized to receive either docetaxel plus doxorubicin and cyclophosphamide (TAC) or 5-florouracil plus doxorubicin and cyclophosphamide. The response rate was significantly higher in the TAC arm (54% v 42%), including patients with unfavorable prognostic factors. Febrile neutropenia occurred more frequently in patients receiving TAC, but the incidence of infection and septic death was low and no greater than in the 5-florouracil/doxorubicin/cyclophosphamide arm. TAC was not associated with an increased risk of cardiotoxicity. Data on time to progression and survival are not yet available. The TAC and doxorubicin/docetaxel regimens have been compared with non-docetaxel-containing programs in randomized adjuvant trials which have completed accrual but are not yet mature. A second generation of adjuvant trials compares sequential versus synchronous docetaxel-based polychemotherapy. In addition, based on preclinical data suggesting a synergistic interaction between docetaxel, platinum salts, and trastuzumab, as well as preliminary data from pilot studies in patients with HER2-positive metastatic disease showing tolerability and activity, adjuvant studies of this novel three-agent combination are in progress in patients with HER2-positive early breast cancer.

Antibodies, Monoclonal↗

PubMed2002

Combination chemotherapy for metastatic breast cancer.

Despite more than four decades of effort, the improvement in survival in metastatic breast cancer has been modest. Recently, however, new drugs such as the taxanes have emerged as pivotal agents in the treatment of metastatic disease and they are now being investigated in the adjuvant setting. In addition, the introduction of molecularly targeted therapies such as trastuzumab provides a new paradigm for the development of biologic treatments. The incorporation of trastuzumab into new combination regimens based on potential molecular synergies is a focus of current research.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

Phase III trial comparing granulocyte colony-stimulating factor to leridistim in the prevention of neutropenic complications in breast cancer patients treated with docetaxel/doxorubicin/cyclophosphamide: results of the BCIRG 004 trial.

This randomized, double-blind, phase III trial compared granulocyte colony-stimulating factor (G-CSF; filgrastim) and leridistim (formerly myelopoietin), a chimeric dual agonist that binds both G-CSF and interleukin-3 receptors, for the prevention of neutropenic complications in patients with breast cancer receiving TAC (docetaxel/doxorubicin/cyclophosphamide) chemotherapy. Patients with metastatic (44%) or localized breast cancer (56%) were randomized to G-CSF 5 microg/kg subcutaneously (s.c.) daily (n = 135), leridistim 5 microg/kg s.c. daily (n = 139), or leridistim 10 microg/kg s.c. every other day alternating with placebo (n = 139). Following administration of TAC (docetaxel 75 mg/m2, doxorubicin 50 mg/m2, cyclophosphamide 500 mg/m2) on day 1, patients received growth factor beginning on day 2 until the postnadir absolute neutrophil count exceeded 1500 cells/ microL. Chemotherapy cycles were repeated every 21 days. The incidence of febrile neutropenia was 7% in the G-CSF arm, 19% in the daily leridistim arm (P = 0.003 for comparison with G-CSF) and 22% in the alternate-day leridistim arm (P < 0.001 for comparison with G-CSF). There was no significant difference between treatment arms in the cumulative percentage of patients experiencing grade 4 neutropenia at some point during therapy (85%-88%). However, grade 4 neutropenia occurred in 53% of cycles in the G-CSF cohort, 61% of cycles in the daily leridistim group (P = 0.063 for comparison with G-CSF), and 63% of cycles in the alternate-day leridistim group (P = 0.015 for comparison with G-CSF). We conclude that G-CSF is superior to leridistim in the prevention of febrile neutropenia in patients with advanced breast cancer receiving TAC chemotherapy. The up-front prophylactic use of G-CSF is a reasonable supportive therapy for patients treated with docetaxel/anthracycline-based combination chemotherapy.

Adult↗

PubMed2002

HER2-positive breast cancer: update on Breast Cancer International Research Group trials.

HER2 gene amplification occurs in approximately 20% of primary breast cancers and is associated with a poor prognosis. Recently, trastuzumab, a humanized murine monoclonal antibody directed against the extracellular domain of HER2, was introduced for the treatment of patients with HER2-overexpressing advanced breast cancer. Trastuzumab has activity as both a single agent and in combination with chemotherapy. However, trastuzumab in conjunction with anthracyclines produces an unacceptably high rate of cardiac toxicity, which has prompted the search for alternative regimens. Docetaxel and the platinum salts are logical candidates to be combined with trastuzumab since these agents exhibit potent synergy with the antibody in preclinical experiments. Furthermore, the available phase II clinical data using the TCH (docetaxel/platinum/trastuzumab) regimen suggest this combination has significant activity. The Breast Cancer International Research Group (BCIRG) 006 trial is a 3-arm adjuvant study comparing doxorubicin/cyclophosphamide followed by docetaxel, the same regimen with trastuzumab administered with docetaxel (TH), and TCH in 3150 women with node-positive or high-risk node-negative, HER2-positive breast cancer. BCIRG 007 compares TH and TCH as first-line therapy in patients with HER2-positive metastatic breast cancer. In both trials, entry is restricted to patients whose tumors are positive for HER2 gene amplification as determined by fluorescence in situ hybridization. The data from these trials, in addition to the results from other ongoing randomized studies, will help define the optimal way to utilize trastuzumab in the management of patients with HER2-positive breast cancer.

Antibiotics, Antineoplastic↗