Search PubMed⌕ Search

Biomedical subjects

N Robert

Publications and source records attributed to N Robert.

At least 19 recordsLinked to original sources
PubMed1999

Uterine adenocarcinoma in a captive sika deer.

A uterine adenocarcinoma with widespread visceral implantation and lymphatic metastases is described in a 4-yr-old captive nulliparous sika deer (Cervus nippon). The tumor was histologically characterized by proliferation of irregularly shaped acini and tubules lined by single- or multi-layered pleomorphic epithelial cells, which were sometimes multinucleated and contained PAS positive mucin. The neoplastic tissue was invasive and showed a marked desmoplastic reaction. A relationship between the tumor and a hormonal imbalance could not be ruled out. This is the first report of a tumor of the reproductive tract in a cervid.

Adenocarcinoma↗
PubMed1998

Sixteen-week multidrug regimen versus cyclophosphamide, doxorubicin, and fluorouracil as adjuvant therapy for node-positive, receptor-negative breast cancer: an Intergroup study.

PURPOSE: The Intergroup conducted this breast cancer adjuvant trial to compare an investigational 16-week regimen with cyclophosphamide, doxorubicin, and fluorouracil (5-FU; CAF). The 16-week regimen features greater doxorubicin and 5-FU dose-intensity than CAF and improved scheduling of antimetabolites with sequential methotrexate and 5-FU, as well as infusion 5-FU. PATIENTS AND METHODS: A total of 646 node-positive, receptor-negative patients were randomly assigned to receive either the 1 6-week regimen or six cycles of CAF. Breast cancer outcomes included recurrence as well as disease-free and overall survival. Toxicity was evaluated by the Common Toxicity Criteria (CTC). Treatment-related quality of life was assessed by the Breast Chemotherapy Questionnaire (BCQ) before, during, and 4 months after treatment in 163 patients. The trial was designed to use one-sided tests of significance for power calculations, but is now reported with both one-sided and the traditional two-sided tests of significance. RESULTS: At a median follow-up of 3.9 years, the estimated 4-year recurrence-free survival rate was 67.5% with the 16-week regimen versus 62.7% with CAF (P = .19, two-sided; P = .095, one-sided). The estimated 4-year survival rate was 78.1% with the 16-week regimen versus 71.4% with CAF (P = .10, two-sided; P = .05, one-sided). CAF produced significantly higher grades of leukopenia, granulocytopenia, and thrombocytopenia, as well as liver and cardiac toxicity, whereas the 16-week regimen produced significantly higher grades of anemia, nausea, stomatitis, and weight loss, as well as skin and neurotoxicity. There were three treatment-related deaths with CAF but none with the 16-week regimen. During treatment, quality of life declined significantly more with the 16-week regimen than CAF, but by 4 months posttreatment, there was no difference. CONCLUSION: The 16-week regimen produced marginally better breast cancer outcomes than CAF with similar toxicity but a greater reduction in during-treatment quality of life. The 16-week regimen should not be used instead of a standard-dose regimen without careful consideration of the 16-week regimen's pros and cons, which include its complicated schedule. It should probably not be tested further, but its antimetabolite schedules and frequent drug administration (ie, dose density) should be considered in the development of new regimens.

Adult↗
PubMed1998

Sporotrichosis in a nine-banded armadillo (Dasypus novemcinctus).

An adult female nine-banded armadillo (Dasypus novemcinctus) died in the quarantine station of a private Swiss zoo. Multifocal ulcerative skin lesions and multiple hemorrhages in the lungs were found at necropsy. The spleen was enlarged and dark red. Histologically, there was diffuse granulomatous infiltration, including multinucleated giant cells, of the skin lesions, lungs, spleen, liver, heart, and kidneys. Abundant periodic acid-Schiff-positive yeastlike cells were demonstrated intracellularly in giant cells and extracellularly scattered throughout the tissues. Morphology of the cells varied, with some nonbudding cells resembling Cryptococcus neoformans and others resembling Sporothrix schenckii. A diagnosis of sporotrichosis was confirmed by immunofluorescence studies. This is the first report of sporotrichosis in an armadillo in a zoological garden and the third report of sporotrichosis in D. novemcinctus.

Animals↗
PubMed1997

[Occurrence of Mycobacterium genavense in birds].

A total of 253 birds were investigated to determine the presence of mycobacteria. Scrapings from various internal organs were stained according to Ziehl-Neelsen, and acid-fast bacilli were found in 26 birds (10.2%). Cultivation of mycobacteria was attempted from 22 livers, 12 spleens, 14 kidneys, 12 lungs, and 9 intestines from these 26 birds. Each sample was first decontaminated using a modified sodium dodecyl sulfate method, and three media were inoculated (Bactec 12 B; Löwenstein-Jensen, Herrold). Using a Polymerase-Chain-Reaction-Restriction-Enzyme-Analysis (PRA), M. genavense could be identified in 19 of 26 birds (73%). M. avium could be isolated from three birds and M. fortuitum from one bird. In total, mycobacteriosis was the primary diagnosis made in 24 of 26 birds (92%). A presumptive diagnosis of mycobacteriosis was already made macroscopically in 14 of these birds. In the remaining 10 cases, bacteriological and histological investigations with specific staining methods were necessary for diagnosis. Several different histological changes were found. We observed individual macrophages as well as epitheloid cell proliferation, with variable, relatively mild inflammatory and fibrous reactions. We could not find any correlation between infection with a mycobacterium species and a specific tissue reaction pattern. This report demonstrates that M. genavense is an important cause of avian mycobacteriosis especially in pet birds.

Animals↗
PubMed1996

A collagen binding protein from Lactobacillus reuteri is part of an ABC transporter system?

The gene coding for a collagen binding protein from Lactobacillus reuteri NCIB 11951 was cloned and sequenced. A genomic lambda library was constructed and recombinant plaques were screened using antisera raised against purified collagen binding proteins from the same L. reuteri strain. The positive plaques were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis, which revealed the expression of a 29 kDa protein, which reacted with the antisera and bound 125I-labelled type I collagen. The sequence of the corresponding gene, cnb showed that the collagen binding protein has sequence similarities to the solute binding component of bacterial ABC transporters.

Amino Acid Sequence↗
PubMed1996

Variations in measured vessel diameters using coronary measurement system.

The Coronary Measurement System (CMS, MEDIS, Leiden, Netherlands) is a film-based QCA system that allows the user to vary the intensity of the light source which illuminates the film, thereby changing the brightness of the image viewed by the digitizing video camera. We found that significant variations in calibration factor (mm/pixel) and measured diameter can occur as a result of variations in either of these intensities. We calculated the variability of the measured diameters for a range of light intensities used for vessel measurement and for calibration. The root mean square deviations in estimated vessel diameter for simulated vessels having actual diameters of 2.03, 2.56, 3.03, and 3.55 mm were 0.13, 0.13, 0.13, and 0.11 mm, respectively, while the ranges (maximum-minimum estimates) were 0.47, 0.45, 0.47, and 0.36 mm, respectively. These results show that while mean errors due to changes in brightness are small, there is the potential for larger errors for certain combinations of light intensities.

Coronary Angiography↗
PubMed1996

Effect of alpha interferon (IFN-alpha) on 2'-5' oligoadenylate synthetase activity in peripheral blood mononuclear cells of patients with chronic hepatitis C: relationship to the antiviral effect of IFN-alpha.

Alpha interferon (IFN-alpha) is, to date, the only treatment with proven efficacy in patients with chronic hepatitis C. However, less than 15% of the patients have a sustained response to IFN-alpha. Interferon acts through the induction of various cellular enzymes. Among them, the 2'-5' oligoadenylate synthetase (2-5OAS) is (at least in part) responsible for a direct antiviral effect of IFN-alpha. The aim of this study was to determine whether basal and IFN-alpha-induced in vivo and in vitro 2-5OAS activities measured in peripheral blood mononuclear cells predict biochemical and virological responses to IFN-alpha in patients with chronic hepatitis C. 2-5OAS activity in peripheral blood mononuclear cells and the antiviral effect of IFN-alpha were studied in 36 patients with chronic hepatitis C (27 men and 9 women; mean age, 44.7 years). Basal in vivo 2-5OAS activity (mean +/- standard error of the mean) was 4.41 +/- 0.69 nmol/10(6) cells. It was significantly induced at month 3 of IFN-alpha therapy (18.07 +/- 2.74 nmol/10(6) cells; P = 0.0001). No significant differences were found in basal in vivo 2-5OAS activities, in IFN-alpha-induced/basal in vitro 2-5OAS activity ratios, in IFN-alpha-induced in vivo 2-5OAS activities, and in IFN-alpha-induced/basal in vivo 2-5OAS activity ratios between the patients with and without a biochemical response (normal alanine aminotransferase activity in serum) or a virological response (normal alanine aminotransferase activity in serum and negative hepatitis C virus RNA detection) at any step of the study. At month 3 of therapy, p69, which is considered to be the active isoform of 2-5OAS, was induced, as demonstrated by Western blot (immunoblot) analysis in 50% of the patients, and induction of the p100 isoform was observed in 70% of the patients. No significant relationship with the response to IFN-alpha therapy was observed. Our results suggest that a deficiency of the IFN-alpha-dependent 2-5OAS system, which could be genetically determined, is unlikely to be responsible for the failure to achieve biochemical and virological responses to IFN-alpha therapy in patients with chronic hepatitis C.

2',5'-Oligoadenylate Synthetase↗
PubMed1996

Phase I trial of high-dose mitoxantrone plus cyclophosphamide and filgrastim in patients with advanced breast carcinoma.

PURPOSE: To determine the maximum-tolerated dose (MTD) of mitoxantrone that could be safely used in combination with cyclophosphamide and filgrastim in patients with advanced breast carcinoma. PATIENTS AND METHODS: Twenty-seven patients with metastatic (n = 24) or locally advanced (n = 3) breast carcinoma received escalating doses of mitoxantrone (16, 20, 24, 28, or 32 mg/m2) plus cyclophosphamide at one of three dose levels: group 1, 1,200 mg/m2; group 2, 2,400 mg/m2; and group 3,600 mg/m2. All patients also received filgrastim 5 micrograms/kg administered subcutaneously beginning on day 2 and continuing until the post-nadir absolute neutrophil count (ANC) was > or = 10,000/microL. Treatment was repeated every 3 weeks if the ANC was > or = 2,000/microL and platelet count > or = 90,000/microL for a maximum of six cycles. Dose escalation occurred within each group if zero of three or one of four patients had dose-limiting toxicity during the first cycle. RESULTS: The MTD of mitoxantrone was 24 mg/m2 in group 1, less than 16 mg/m2 in group 2, and 28 mg/m2 in group 3. Neutropenia was dose-limiting, and cumulative neutropenia and thrombocytopenia occurred with continued therapy. Nonhematologic toxicity consisted predominantly of nausea, vomiting, alopecia, and fatigue. Three patients (11%) had a > or = 10% decrease in the left ventricular ejection fraction (LVEF), one patient (4%) had a decrease in the LVEF below normal, and none developed clinical congestive heart failure. Of patients with stage IV breast carcinoma who had not received prior chemotherapy for advanced disease, objective responses occurred in nine of 20 (45%), and the median response duration was 5 months. CONCLUSION: In combination with 600 mg/m2 of cyclophosphamide and filgrastim, the MTD of mitoxantrone is 28 mg/m2, a dose that is approximately twofold to 2.8-fold higher than the conventional dose used without a hematopoietic growth factor.

Adult↗
PubMed1995

CD5-mediated specific delivery of DNA to T lymphocytes: compartmentalization augmented by adenovirus.

Specific DNA delivery has been achieved via interactions between an asialoorosomucoid-polylysine conjugate and the asialoglycoprotein receptor. We have now extended this technology to another cell type. In order to achieve DNA delivery uniquely to T cells, we have employed an antibody-polylysine conjugate which binds and is internalized via CD5. Binding analyses of the T101 monoclonal antibody to Jurkat cells and freshly isolated human peripheral T lymphocytes were performed and Scatchard plots revealed Kd values of 1.4 and 1.2 pM, respectively. To introduce DNA into the T cell, a complex of T101-polylysine and the luciferase plasmid was formed (T101-PL-DNA). 125I-labeled antibody alone or T101-PL-DNA complexes were both shown to internalize. Subcellular fractionation indicated that the complex remained in the endosomal compartment of the cell for up to 90 min. However, with the addition of adenovirus particles, there was a decrease of labeled complex in the endosomal fraction over time suggesting it was no longer 'tethered' to the endosome vesicle. In vitro transfections confirmed this result showing the addition of adenovirus particles during incubation resulted in increased expression of the luciferase protein. Without adenovirus, there was limited expression of the transduced gene. These data revealed that T101 can deliver DNA via an antibody-PL conjugate. The addition of adenovirus allowed the DNA to escape the endosome enabling expression of the reporter gene.

Adenoviridae↗
PubMed1995

Proteolytic activity of proteasome on myofibrillar structures.

The physiologic function of proteasome remains unclear. Evidence suggests a role in degradation of ubiquitin-protein conjugates, MHC antigen presentation, and some specificity of substrate within certain cell types. To explore further the properties of proteasome we have examined its effect on a well defined structure, the myofibril. We find that despite its large size (20S) proteasome is able to degrade myofibrils and intact, permeabilized muscle fibrils. The proteins degraded showed some specificity because actin, myosin and desmin were degraded faster than alpha-actinin, troponin T and tropomyosin. Changes in ultrastructure were slow and included a general loss of structure with Z and I bands effected before the M band and costameres.

Animals↗
PubMed1995

Activity of the interferon-induced 2',5'-oligoadenylate synthetase in patients with chronic hepatitis C.

The interferon-induced 2',5'-oligoadenylate synthetase (2-5OAS) is responsible, at least in part, for the antiviral state established in cells in response to viral infections. The purpose of this work was to study the relationship between hepatitis C virus (HCV) infection and 2-5OAS in patients with chronic hepatitis C. Peripheral blood mononuclear cells (PBMC) of 27 patients with chronic hepatitis C were investigated, as well as PBMC of 10 control subjects. Then, the patients were treated with 3 mu interferon-alpha 2a three times per week. At month 3 of therapy, PBMC were sampled. Of the total PBMC samples obtained, half were used for determination of in vivo 2-5OAS activity. The remaining cells were cultured for 24 h in either the absence or presence of 500 U/ml of interferon-alpha 2a for the determination of in vitro 2-5OAS activity. The mean basal in vivo 2-5OAS activities were 3.6 +/- 2.8 nmol/10(6) cells in patients versus 1.6 +/- 1.1 nmol/10(6) cells in controls (p < 0.01). Basal in vivo 2-5OAS activity did not correlate with mean HCV viremia, quantified by a "branched DNA"-based assay. Before treatment, interferon-alpha was detected in the serum of 2 patients in 27. After a 24 h culture of PBMC in the presence of interferon, in vitro 2-5OAS activity was significantly induced in the PBMC of both the patients and the controls. However, in vitro induction of 2-5OAS activity was significantly lower in the PBMC of the patients than in the PBMC of the controls (p < 0.01). At month 3 therapy, in vivo 2-5OAS activity was significantly induced (20.5 +/- 17.9; p < 0.0001). In vitro IFN inductions of 2-5OAS activity in PBMC before treatment and at month 3 of therapy were not significantly different. In conclusion, in vivo 2-5OAS activity is significantly induced in patients with chronic hepatitis C, but endogenously produced interferon-alpha does not seem to be involved. Chronic induction of 2-5OAS activity results in a decreased sensitivity of PBMC to exogenous interferon induction. Whether this phenomenon plays a role in the resistance of chronic hepatitis C to interferon therapy remains uncertain.

2',5'-Oligoadenylate Synthetase↗
PubMed1995

Leukemogenic potential of adjuvant chemotherapy for early-stage breast cancer: the Eastern Cooperative Oncology Group experience.

PURPOSE: Since large numbers of patients with early-stage breast cancer now receive adjuvant chemotherapy containing cyclophosphamide, a known leukemogenic agent, it is important to determine the risk of secondary acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Therefore, we identified all cases of AML or MDS developing in patients treated on six clinical adjuvant chemotherapy trials conducted by the Eastern Cooperative Oncology Group (ECOG). PATIENTS AND METHODS: The patients population included 2,638 patients with previously untreated primary operable breast cancer entered onto six clinical trials conducted by the ECOG between 1978 and 1987. There are 19,200 persons-years of follow-up study and a mean follow-up duration of 7.3 years. Clinical data were obtained from flow sheets submitted to the ECOG Data Management Office. RESULTS: Of 2,638 patients at risk with 19,200 person-years of follow-up study, three patients developed MDS (two with a characteristic cytogenetic abnormality). Two patients developed acute leukemia; however, one had adult T-cell leukemia associated with human T-lymphotrophic virus type 1 (HTLV-1) and a second patient developed AML after receiving additional cyclophosphamide for metastatic breast cancer. The estimated incidence rate for MDS is three per 19,200 or 16 per 100,000 person-years of follow-up study with a 95 percent confidence interval of three to 46 per 100,000 person-years. If all five patients (three MDS and two acute leukemia) are included, the estimated incidence rate is five per 19,200 or 26 per 100,000 person-years of follow-up study with a 95 percent confidence interval of eight to 61 per 100,000 person-years. CONCLUSION: These data suggest that the risk of secondary AML or MDS among patients with early breast cancer who receive standard-dose cyclophosphamide-containing adjuvant chemotherapy is not much higher than in the general population. However, physicians must remain alert to the possible long-term consequences of alkylating agent and anthracycline-based chemotherapy.

Acute Disease↗
PubMed1995

Eastern Cooperative Oncology Group studies of paclitaxel and doxorubicin in advanced breast cancer.

Based on their single-agent activity in metastatic breast cancer, paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) and doxorubicin have been alternated and combined in Eastern Cooperative Oncology Group studies to identify a tolerable dose and schedule. A pilot trial in patients who had received no more than one prior chemotherapy regimen alternated paclitaxel 200 mg/m2 and doxorubicin 75 mg/m2 every 3 weeks. Seven of 12 patients had objective (complete plus partial) responses. A second (phase I) trial combined doxorubicin as an intravenous push and paclitaxel as a 24-hour continuous infusion. To evaluate the effect of the schedule on toxicity, the drug administration sequence (doxorubicin-->paclitaxel or paclitaxel-->doxorubicin) was alternated both between and within patients. initial doses were paclitaxel 150 mg/m2 and doxorubicin 50 mg/m2 in six patients, with a subsequent six patients receiving 175 and 60 mg/m2, respectively. Dose-limiting mucositis was seen at the second dose level when paclitaxel preceded doxorubicin, suggesting an important role for the administration sequence in determining toxicity (and possibly efficacy) in this regimen. These results support the sequence of doxorubicin 50 mg/m2 followed by paclitaxel 150 mg/m2 as the maximum tolerated dose. This combination has been incorporated as a treatment arm in an ongoing randomized prospective phase III Intergroup trial. By comparing the combination with both drugs as single agents (with crossover to the opposite agent at disease progression), investigators will attempt to assess response, toxicity, and time to progression as well as the degree of cross-resistance between the two agents. Given the poor prognosis of patients with advanced breast cancer, the three arms also will be evaluated in terms of patients' quality of life.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Characterization of an interferon-induced 48-kD protein immunologically related to the double-stranded RNA-activated protein kinase PKR.

Polyclonal antibodies raised against purified and urea-denatured double-stranded protein kinase (PKR) from human origin cross-reacted by immunoblotting with a 48-kD protein (p48) induced by the three types of interferon (IFN), alpha, beta, and gamma. The induction of p48 is IFN dose dependent and its accumulation occurs a few hours after the addition of IFN. The induction of p48 is blocked by actinomycin D. Analysis by two-dimensional gel isoelectric-focusing, revealed p48 as a single spot with an isoelectric point (pI) of 6.8. In the same experiment the PKR was revealed as several subspecies with pI values in the pH range of 7.4-8.0. Cell fractionation experiments indicated that PKR and p48 have different subcellular localizations: PKR was found to be associated with the microsomal pellet as shown previously whereas p48 was recovered in the microsomal supernatant fraction. In addition to these differences, PKR and p48 were found to be differentially expressed in some human cells treated with the three types of IFN. For example, in HeLa cells, IFN-alpha or IFN-beta induced similarly both PKR and p48 whereas IFN-gamma induced mainly p48. In U937 cells in which PKR was not expressed with or without IFN treatment, p48 was strongly induced by all three types of IFN. These results suggest different mechanisms for the induction of PKR and p48. In view of its presence in different types of human cells and its induction by different types of IFN, it is possible to suggest that p48 might play an important role in mediating some of the action of IFN.

Enzyme Activation↗
PubMed1994

Binary vascular reconstruction from a limited number of cone beam projections.

This paper describes a method to perform reconstruction of vascular cross-sectional images from a limited number of x-ray angiographic cone-beam projections. It is assumed that the projection data can be simplified by identifying blood vessels in each angiogram and removing signals due to other structures. Under these conditions, the x-ray attenuation coefficient, mu, can be modeled as a binary variable having a value mu 0 within the vessel and "0" outside. The reconstruction is performed by minimizing a cost function using the method of simulated annealing. In this paper, we demonstrate that the introduction of a priori information allows one to reconstruct a sphere and a simulated branched vessel from three views with, respectively, 97% and 93% of voxels having correct values. The addition of a continuity constraint for the reconstruction of the branched vessel resulted in further reduction in the percentage of misplaced voxels. Calculations require from one to six hours of CPU time on a Sun SparcStation 2 computer for the cases investigated here. The effect of noise, "cooling" schedule, and number of views on the reconstruction are examined using simulated vessel projections. Modifications to our approach to accelerate the reconstruction are also discussed.

Angiography↗
PubMed1994

Performance of glass fiber antiscatter devices at mammographic energies.

Using fiber optic manufacturing techniques, it is possible to produce a radiographic grid that discriminates against scattered radiation in two dimensions. Such grids consist of septa composed of glass with a high lead content; the interspace material is air, so that approximately 80% of the grid area is open. In this way, effective high ratio grids can be produced with relatively low Bucky factors. The performance of samples of such grid material is characterized in terms of both scatter rejection and dose efficiency for application in digital mammography in both slot-beam and area-beam geometry. For area beams, five- to tenfold improved scatter rejection relative to conventional grids was observed. In slot configurations, such grids could provide improved SNR/dose performance and more effective utilization of the heat loading capability of the x-ray source.

Fiber Optic Technology↗
PubMed1994

Cloning, sequencing, and expression in Escherichia coli of the D-hydantoinase gene from Pseudomonas putida and distribution of homologous genes in other microorganisms.

Pseudomonas putida DSM 84 produces N-carbamyl-D-amino acids from the corresponding D-5-monosubstituted hydantoins. The gene encoding this D-hydantoinase enzyme was cloned and expressed in Escherichia coli. The nucleotide sequence of the 1.8-kb insert of subclone pGES19 was determined. One open reading frame of 1,104 bp was found and was predicted to encode a polypeptide with a molecular size of 40.5 kDa. Local regions of identity between the predicted amino acid sequence and that of other known amidohydrolases (two other D-hydantoinases, allantionase and dihydroorotase) were found. The D-hydantoinase gene was used as a probe to screen DNA isolated from diverse organisms. Within Pseudomonas strains of rRNA group I, the probe was specific. The probe did not detect D-hydantoinase genes in pseudomonads not in rRNA group I, other bacteria, or plants known to express D-hydantoinase activity.

Amidohydrolases↗