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D Beck

Publications and source records attributed to D Beck.

At least 73 records · Page 4Linked to original sources
PubMed1994

Genotypic and phenotypic diversity of Rhizobium isolated from chickpea (Cicer arietinum L.).

The diversity of 16 strains of chickpea-infective rhizobia from various geographical origins was analysed using genotypic and phenotypic approaches. Multilocus enzyme electrophoresis was performed, and restriction fragment length polymorphisms of the amplified 16S + IGS (intergenic spacer) rRNA gene, assimilation of 147 carbon sources, antibiotic resistance, and tolerance to NaCl and extreme pH values and temperatures were tested. These approaches had different discriminating powers. Esterase polymorphisms gave a unique pattern for each strain, allowing this method to be used for strain fingerprinting. Genetic distances between strains were estimated. The three approaches used in this study yielded consistent results. They evidenced high heterogeneity among the strains, and made it possible to classify the strains into two clusters. Isozyme patterns for superoxide dismutase were particularly interesting, since they delineated the same two groups. The phenotypic tests clearly confirmed the existence of two genetic groups on the basis of 11 phenotypic characters. Owing to the large phylogenetic distance between the two groups of strains, the taxonomic status of chickpea-infective strains is discussed.

Bacterial Proteins↗
PubMed1994

Comparative metabolism of SC-42867 and SC-51089, two PGE2 antagonists, in rat and human hepatocyte cultures.

1. The metabolism of SC-42867 and SC-51089, two PGE2 antagonists, was studied in cultured rat and human hepatocytes. Both compounds possess an 8-chlorodibenzoxazepine moiety, but differ from each other by the nature of the side chain connected to the nitrogen atom. SC-42867 and SC-51089 and their in vitro metabolites were separated by reversed-phase hplc. The major metabolites of both compounds were identified by mass spectrometry (ms) analysis. 2. SC-42867 was metabolized on the tricyclic moiety only. Oxidative N-dealkylation with opening of the oxazepine ring was the major metabolic pathway obtained in rat hepatocytes. The metabolic profile obtained in cultured human hepatocytes was comparable with that of cultured rat hepatocytes. However, the compound was metabolized to a much lower extent by the human cells. 3. SC-51089 was extensively metabolized by both cultured rat and human hepatocytes. Human cells metabolized this compound quite differently than cultured rat hepatocytes. Aromatic hydroxylation with consequent glucuronidation and sulphation were the main metabolic pathways observed in cultured human hepatocytes. Oxidative N-dealkylation with opening of the oxazepine ring and consequent glucuronidation was the major metabolic pathway observed in rat hepatocytes. Further metabolism occurred, in contrast with the human hepatocytes, mainly on the side chain. 4. The present in vitro results are compared with data of previous in vivo studies performed in rat.

Adult↗
PubMed1994

Transvaginal sonography, color flow imaging, computed tomographic scanning, and CA 125 as a routine follow-up examination in women with pelvic tumor: detection of recurrent disease.

We were trying to determine whether transvaginal sonography combined with color flow imaging should be used routinely for detecting recurrent pelvic tumors in patients treated for pelvic cancer. Eighteen patients who had completed their treatment for pelvic tumor were examined every 6 months by gynecologic examination, a CT scan, serum CA 125 levels, and transvaginal sonography with color flow imaging. Laparotomy or fine-needle biopsy was performed when a recurrent pelvic mass was observed or suspected on CT scans or transvaginal sonography. In nine of 18 patients a recurrent pelvic tumor was observed or suspected on CT scans or on transvaginal sonography. A recurrent pelvic tumor was diagnosed on laparotomy in five patients. In four patients, only a fine-needle biopsy was performed and only two of them had positive results. The highest sensitivity and specificity for detecting recurrent pelvic tumors were achieved by transvaginal sonography (100 and 91%, respectively) and by color flow imaging (86 and 100%, respectively). Intratumoral blood vessels were detected in all cases with recurrent pelvic tumors, and in only one of these cases the PI was high. We recommend a routine follow-up with transvaginal sonography in women completing their treatment for pelvic tumors. When a recurrence of tumor is only suspected on transvaginal sonography, color flow imaging may be used as an additional diagnostic tool.

Aged↗
PubMed1993

[Late sequelae in a group of children and adolescents treated for cancer between 1981 and 1986 in Switzerland].

An ever-growing number of children with malignant diseases can today be cured and will have prolonged survival. Their quality of life, which can be altered by a substantial number of late effects of the disease or its treatment, is a prominent field of long-term assessment. In a cross-sectional study based on clinical and paraclinical parameters and covering 59 children and young adults treated between 1981 and 1986 for a childhood malignant disease, we investigated late effects in the long-term survivors. Late effects were found in 36 (61%) of these patients; their spectrum is wide, but most often affected are the CNS and the musculoskeletal system. Two thirds of the patients have mild or moderate and one third severe problems. The frequency of the late effects and the type of problem vary greatly according to the initial diagnosis; our results show a significant difference of severity according to the number of affected systems (p < 0.05). The results of our study match those of other similar reports and confirm the high frequency of late effects in survivors of pediatric cancer. A prospective study, assessing a large population of patients, is needed to determine the underlying causes and to develop primary and secondary prevention strategies.

Adolescent↗
PubMed1993

Prognostic factors and long-term survival in endometrial adenocarcinoma with cervical involvement.

The clinical, surgical, and histopathologic data from 202 patients with endometrial adenocarcinoma with cervical involvement are presented. One hundred fifty-one (75%) had histopathologically confirmed cervical involvement at the time of their definitive surgery, while in 51 (25%) no cervical involvement was conclusively identified. The 5-year actuarial survival for patients with true surgical stage II endometrial carcinoma (N = 24) was 76%. Extrauterine disease was documented in 32% (27/84) of patients in which the primary treatment modality was surgical. The 5-year actuarial survival was 65% for all patients with clinical surgical stage II disease. There appeared to be a survival advantage for patients treated by radical surgery as compared with more conventional treatments, especially in patients with numerous high-risk factors. The subgroup of patients (N = 53) having tumor grossly involving the cervix had a 5-year survival of 48%. In this subgroup of patients, radical hysterectomy offered improved 5-year survival over more traditional forms of treatment, particularly compared with simple hysterectomy or combined treatment with radiation and surgery. Multivariate analysis positively correlated myometrial invasion, grade, uterine serosal involvement, lower uterine segment involvement, adnexal metastasis, pelvic metastasis, aortic node metastasis, and peritoneal cytology, with disease-free survival. Clinical and surgical findings correlated poorly; therefore, primary surgical evaluation is recommended when possible.

Adenocarcinoma↗
PubMed1993

Culturing of primary hepatocytes as entrapped aggregates in a packed bed bioreactor: a potential bioartificial liver.

Conventional culture systems for hepatocytes generally involve cells cultured as flat, monolayer cells, with limited cell-cell contact, in a static pool of medium, unlike the liver in vivo where the parenchymal cells are cuboidal, with extensive cell-cell contact, and are continuously perfused with blood. We report here a novel bioreactor system for the culturing of primary hepatocytes with cuboidal cell shape, extensive cell-cell contact, and perfusing medium. The hepatocytes were inoculated into the bioreactor and allowed to recirculate at a rate optimal for them to collide and form aggregates. These newly-formed aggregates were subsequently entrapped in a packed bed of glass beads. The bioreactor was perfused with oxygenated nutrient medium, with controlled oxygen tension, pH, and medium perfusion rate. The hepatocytes were viable for up to the longest time point studied of 15 days in culture based on urea synthesis, albumin synthesis and cell morphology. Light microscopy studies of hepatocytes cultured for 15 days in the bioreactor showed interconnecting three-dimensional structures resembling the hepatic cell plate in the liver organ. Electron microscopy studies on the same cells revealed ultrastructure similar to the hepatocytes in vivo, including the presence of plentiful mitochondria, rough and smooth endoplasmic reticulum, glycogen granules, peroxisomes, and desmosomes. We believe that our hepatocyte bioreactor is a major improvement over conventional culture systems, with important industrial applications including toxicology, drug metabolism, and protein/peptide synthesis. The hepatocyte bioreactor concept may also be used as the basis for the development of a bioartificial liver to provide extracorporeal hepatic support to patients with hepatic failure.

Albumins↗
PubMed1993

Metabolism in vitro of radioiodinated N-isopropyl-p-iodoamphetamine by isolated hepatocytes.

An in vitro technique for the determination of radiopharmaceutical metabolism has been developed using isolated hepatocytes. Radioiodinated N-isopropyl-p-iodoamphetamine (IMP; iofetamine, USP) was employed a model tracer in these studies because its labeled metabolites are well-characterized. Hepatocytes isolated from the rat and human produced labeled metabolites in vitro for up to 4 h in a manner similar to that reported for humans in vivo. Identical metabolites were generated by all cell types investigated, but the rate of metabolism differed (rat >> human; female > male; fresh > frozen). The utility of this methodology for the preclinical evaluation of potential radiopharmaceuticals is described.

Adult↗
PubMed1993

[Surgery with the laser scalpel. Physical principles and clinical effectiveness].

BACKGROUND: The conventional surgical method for cutting vascularized tissue with scalpel and scissors may now be improved by use of the laser scalpel. In particular, the frequent interruption necessitated and the poor visibility caused by bleeding may be mitigated owing to the haemostatic properties of laser light. This instrument may be of particular value for tasks involving extrabulbar structures, such as extraocular muscles and lacrimal tissue, as well as for facial surgery. MATERIALS AND METHODS: The mode of action and physical properties of a new laser scalpel are described and its characteristics compared with those of other instruments on the market. The probe consists of a clad, sculptured silica fibre with a core diameter of 0.6 mm and a conical 0.15 mm-diameter cutting tip. Radiation generated by a low cw-Nd:YAG laser module is fed into the probe, at the exit point of which a maximal power density of 57 kW/cm2 is attained. Radiated laser energy penetrates the tissue as an incision is made, thereby inducing an efficient blood flow stasis which is amplified by thermal energy diffusing from the immediate surroundings of the scalpel tip. RESULTS: In this report, the laser scalpel is implemented for the excision of a vascularized, amelanotic, facial naevus. Both the cutting and haemostatic effects were found to be excellent, occurrence of the latter phenomenon being supported by ultrastructural findings. The healing response was comparable to that observed after conventional surgery. CONCLUSION: The new laser scalpel represents an inexpensive and effective cutting and haemostatic tool powered by a standard cw Nd:YAG laser module, with a wide spectrum of potential applications.

Aged↗
PubMed1993

The effects of intraoperative administration of OKT3 during renal transplantation.

The use of the monoclonal antibody OKT3 for induction immunosuppression in renal transplantation is increasing--however, the safety of intraoperative administration continues to be questioned because of first-dose effects. The current study was designed to examine the effects of intraoperative administration of OKT3 on the cardiovascular and pulmonary systems in 161 consecutive renal transplant recipients. Patients receiving OKT3 intraoperatively during renal transplant (99 cadaver recipients) were compared with 62 patients not administered the drug (31 cadaver, 25 living-related-donor, 6 living-nonrelated donor). Intraoperative airway pressure (highest, average), O2 saturation (SaO2), temperature, blood pressure changes, cardiac rhythm, and bronchospasm were compared in these two groups. Significant physiologic changes noted in the group receiving OKT3 included increased temperature (both intraoperative and postoperative), decreased SaO2 (postoperative), and increased FiO2 (postoperative). Despite these differences, no clinically significant changes were noted in the group receiving OKT3. OKT3 induction given at the time of surgery was associated with a significantly increased one- and three-year graft function. This study demonstrates that first-dose administration of OKT3 intraoperatively during renal transplantation is safe and effective.

Adult↗
PubMed1993

Uterine artery flow velocity waveforms and color flow imaging in women with perimenopausal and postmenopausal bleeding. Correlation to endometrial histopathology.

We performed Doppler studies of the uterine artery in 85 women with postmenopausal and perimenopausal bleeding. Sixty-six women had non-malignant changes and 19 women had malignant changes on histologic examination of the endometrium. Uterine fibroids were detected in 30 women. When malignant changes were detected in the endometrium, uterine artery resistance index was always below 0.83. The mean uterine artery resistance index was significantly lower in the group of women with pathologic changes of the endometrium (RI = 0.77 +/- 0.03) compared to the group with non pathologic changes (RI = 0.85 +/- 0.08 p < 0.01), excluding the women with uterine fibroids. The lowest mean resistance index in the uterine artery was observed in the group of women with uterine fibroids (RI = 0.60 +/- 0.09 p < 0.001). In five of six patients with endometrial carcinoma blood vessels were detected around the myometrium by using color flow imaging. Their RI was always less than 0.5. In five patients, blood vessels were detected in uterine fibroids but their RI was always more than 0.5. All six women with endometrial carcinoma but only seven of 13 women with endometrial hyperplasia, had endometrial thickness greater than 5 mm. Doppler velocimetry of the uterine artery carries a high sensitivity (100%) in detecting pathological changes of the endometrium in patients presenting with postmenopausal or perimenopausal bleeding. The presence of high resistance in this vessel, may allow a more conservative approach in this group of patients.

Aged↗
PubMed1993

Screening for ovarian cancer in women with breast cancer with transvaginal sonography and color flow imaging.

The aim of the present study was to determine the efficacy of transvaginal color flow imaging as a screening tool for ovarian cancer. Six hundred patients with previous breast carcinoma were screened for ovarian cancer. Screening was performed using transvaginal sonography with color flow imaging. Serum CA 125 levels were measured in patients with abnormal sonographic findings. Eighty-three percent of the ovaries were detected in the premenopausal patients by ultrasonographic scanning and only 26% of the ovaries were detected in the postmenopausal patients. Intraovarian blood vessels were detected in 11% of the premenopausal women. The PI was less than 1 in 80% of these ovaries, but, on repeated examinations, the values of PI increased in all the blood vessels to greater than 1. Intraovarian blood vessels were detected in 1.8% of the normal ovaries observed in the postmenopausal women, but PI was always greater than 1. Eleven women with complex ovarian cysts (not simple) and one woman with enlarged ovaries underwent explorative laparotomy. In three women, primary malignant ovarian tumors were diagnosed and in one woman metastatic ovarian cancer was diagnosed. The specificity of sonography in detecting malignant ovarian tumors was 97.5% and the positive predictive value was 25%. The specificity of color flow imaging in detecting primary malignant ovarian tumors was 99.8% and the positive predictive value was 60%. In selected groups of women, screening for ovarian cancer with transvaginal color flow imaging may be justified.

Adult↗
PubMed1992

Differentiation-related expression of adhesion molecules and receptors on human neuroblastoma tissues, cell lines and variants.

The expression of cellular adhesion molecules (CAM) involved in cell adhesion and immune recognition was measured on neuroblastoma tissue samples, on a neuroblastoma (NB) cell line, SK-N-SH, and on 3 phenotypically different variants, SH-SY5Y, SH-EP, SH-IN, representing neuronal, Schwannian/glial or intermediate NB-cell types. Immunohistochemical analysis of CAM expression by NB and related tumors at different stages of differentiation revealed a co-expression of several CAM (ICAM-1/CD54, LFA-3, VLA-2 and HLA-ABC) associated with low stages and more highly differentiated NB tumors and peripheral neuroepitheliomas (PN). In contrast, N-CAM was uniformly expressed on all NB tumors. Flow cytometric analysis of CAM surface expression by SK-N-SH and variant cells revealed highly variable phenotypes. Expression of ICAM-1, LFA-3, VLA-2 and HLA-ABC molecules was associated with the epithelial cell type represented by the SH-EP variant. In contrast, low expression of these molecules and high expression of N-CAM was associated with the neuronal SH-SY5Y cells. Exposure of the NB cells to differentiation inducers (retinoic acid, 5'-bromodeoxyuridine and phorbol esters) and cytokines (tau-interferon, alpha-tumor necrosis factor) resulted in a variable up-regulation of the expression of all CAMs, except N-CAM, regardless of the type of differentiation induced. In an attempt to establish a link between the pattern of expression of CAM on NB cells and their susceptibility to natural killer (NK) or lymphokine-activated killer (LAK) cell lysis, the analysis revealed that NB cells expressing CAM and a differentiated phenotype were less susceptible to NK lysis, but no difference in the sensitivity of the NB cell types to LAK effectors was observed. Treatment of NB target cells with cytokines or PMA decreased their susceptibility to NK and LAK lysis, while induction of differentiation with RA or BUdR resulted in no changes in the sensitivity to NK and LAK lysis. In conclusion, expression of HLA-ABC and several co-regulated CAMs was shown to be associated with a differentiated phenotype in NB, with an overall decreased sensitivity to NK/LAK effector cells.

Antigens, Differentiation, T-Lymphocyte↗