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Biomedical subjects

A Rodriguez

Publications and source records attributed to A Rodriguez.

At least 145 records · Page 8Linked to original sources
PubMed1998

Application of gas and liquid chromatography-mass spectrometry to the evaluation of pirimiphos methyl degradation products in industrial water under ozone treatment.

The organophosphorus compound pirimiphos methyl was oxidized in water under ozonolysis in the presence of formulating agents. A rapid sample handling procedure was developed based on liquid-solid extraction with nonporous carbon cartridges. This sorbent material allowed recovery of the polar degradation products (DPs). Analysis of oxidized solutions was performed with both GC-ion trap (IT)-MS using either electron impact or chemical ionization as ionization modes and LC-atmospheric pressure ionization (API)-MS using either an ionspray (ISP) or an atmospheric pressure chemical ionization (APCI) interface in order to confirm the presence of DPs. The performances of both technologies were evaluated for structure elucidation and quantitation by using pirimiphos methyl, 2,4-aminophenol and cyanuric acid as external standards of DPs. LC-API-MS techniques allowed the detection of six DPs, of which two were not detected by GC-IT-MS techniques, even after a derivatization procedure with BF3-MeOH reagent. ISP was the most suitable ionization method for identifying the DPs, because sodium or potassium adduct ions were of great help in confirming the molecular mass of unknowns. APCI provided more fragmentation patterns than ISP. However unequivocal identification of all DPs was impossible and only a tentative degradation pathway of pirimiphos methyl in water under ozone is proposed. At the end of the reaction time, DPs accounted for between 70 and 85% of the initial concentration of methyl pirimiphos.

Chromatography, Liquid↗
PubMed1998

Dredd, a novel effector of the apoptosis activators reaper, grim, and hid in Drosophila.

Caspases are widely conserved proteases considered to be essential effectors of apoptosis. We identified a novel Drosophila gene, dredd, which shares extensive homology to all members of the caspase gene family. Cells specified for programmed death in development exhibit a striking accumulation of dredd RNA that requires signaling by the death activators REAPER, GRIM, and HID. Furthermore, directed misexpression of each activator was sufficient to drive ectopic accumulation of dredd RNA. Heterozygosity at the dredd locus suppressed apoptosis in transgenic models of reaper- and grim-induced cell killing, demonstrating that levels of dredd product can modulate signaling triggered by these death activators. Finally, expression of REAPER, GRIM, and HID was found to trigger processing of DREDD protein precursor through a mechanism that is insensitive to, and upstream of, known caspase inhibitors. Taken together, these observations establish mechanistic connections between activators of apoptosis and a new downstream death effector in Drosophila.

Amino Acid Sequence↗
PubMed1998

9-Hydroxy-9-(3-methylbut-3-en-1-ynyl)-9H-fluorene-1-carbonitrile.

The N atom in the title compound, C19H13NO, lies -0.0365 (14) A from the plane formed by the fluorene system, and the C [symbol: see text] N distance is 1.143 (2) A. The C [symbol: see text] C distance is 1.191 (2) A, and the ethynyl group deviates slightly from linearity, with C-C [symbol: see text] C-C bond angles of 172.0 (1) and 176.1 (2) degrees. Terminal CH2 and CH3 groups are 50:50 disordered, with equal C-C distances of 1.408 (3) and 1.406 (3) A.

Crystallography, X-Ray↗
PubMed1998

Strategies to decrease costs associated with GBS prophylaxis in preterm gestations.

Objective: 1) To evaluate the costs associated with a practice of routinely culturing women for Group B beta-Streptococcus (GBS) who are at risk for preterm delivery. 2) To evaluate the charges associated with a policy of empiric antibiotic therapy in women suspected of imminent delivery prior to 37 weeks gestation.Methods: In our hospital, women who present with preterm contractions (PTC), preterm labor (defined as uterine contractions resulting in cervical change, PTL), and preterm rupture of the membranes (PROM) were cultured for GBS. Women with PTL and PROM received parenteral antibiotic therapy pending availability of culture results (48 hours). We reviewed the records of women who participated in a study to determine the sensitivity and specificity of a rapid test for GBS (Am J Obstet Gynecol 1997;176:S35). Results of the Lim broth culture, our gold standard, were used for this analysis. The charges for performing cultures ($32/culture) and administering intravenous ampicillin ($54/dose) were calculated.Results: There were 118 women with PTC, 52 women with PTL, and 64 with PROM. Thirty-four (14.5%) of the cultures were positive. The results are presented below.In women with PTC, the incidence of GBS was 12.7%. The culture results were available and guided care in only the 6 women who delivered between 2 and 7 days. In women with PTL the incidence of positive cultures was 11.5%. All of the women received antibiotics pending results of cultures. The majority of the women had delivery delayed 48 hours until results were available. Care was modified in the 7 women who delivered between 2 and 7 days. In women with PROM the incidence of GBS was 20.3%. The culture results were available and guided therapy in 11 women.Conclusions: Our findings suggest that GBS cultures have limited clinical value in women with PTC. Only 6 women, 5.5%, had their care modified as a result of the cultures, at a cost of $3776. In women with PTL, we over-treated the majority of women with antibiotics, most of whom delivered after culture results were available. Cultures had minimal impact on management. Antibiotics should be reserved for women whose labor is progressing on tocolysis. In women with PROM, most delivered prior to availability of culture results. We would have saved $2048 had no cultures been obtained. These results are probably irrelevant, if routine antibiotic administration is utilized in PROM to prolong latency intervals regardless of GBS status.

Journal Article↗
PubMed1998

4-Nitro-1-(trimethylsilylethynyl)benzene.

The title molecule, C11H13NO2Si, lies on a mirror plane, with only one methyl group lying out of plane. The C[symbol: see text]C triple bond has a length of 1.199 (4) A. Bond angles Si-C[symbol: see text]C and C[symbol: see text]C-C(Ar) are 177.9 (3) and 178.0 (3) degrees, respectively. The Si-Csp3 bond lengths are 1.831 (4) and 1.838 (3) A, while the Si-Csp distance is 1.839 (3) A.

Crystallography, X-Ray↗
PubMed1998

Risk factors, treatment, and outcome of central nervous system recurrence in adults with intermediate-grade and immunoblastic lymphoma.

To evaluate the incidence, risk factors, and outcome of central nervous system (CNS) recurrence in adult patients with non-Hodgkin's lymphoma, we evaluated 605 newly diagnosed patients with large-cell and immunoblastic lymphoma who participated in prospective chemotherapy studies. The Kaplan-Meier estimate of probability of CNS recurrence at 1 year after diagnosis was 4.5% (95% confidence interval [CI], 4.4 to 4.6). Twenty-four patients developed CNS recurrence after a median of 6 months from diagnosis (range, 0 to 44 months). In univariate analysis, an increased risk for CNS recurrence was associated with an advanced disease stage (P = .0014), an increased LDH (P = .0000), the presence of B-symptoms (P = . 0037), involvement of more than one extranodal site (P = .0000), poor performance status (P = .0005), and B-cell phenotype (P = .008). Bone marrow involvement (P = .005), involvement of parenchymal organs (P = .03), and involvement of skin, subcutaneous tissue, and muscle (P = .002) were also associated with an increased risk for CNS disease. Multivariate logistic regression analysis identified only involvement of more than one extranodal site (P = .0005) and an increased LDH (P = .0008) as independent predictors of CNS recurrence. Established CNS recurrence had a poor prognosis. Only 1 of 24 patients remains alive and the Kaplan-Meier estimate of probability of survival at 1 year after the diagnosis of CNS recurrence is only 25.3% (95% CI, 6.9 to 43.7). Intrathecal treatment provided symptomatic benefit in only 1 of 6 patients. Radiation treatment provided symptomatic improvement in 6 of 9 patients treated. However, remissions were short and followed by systemic or CNS recurrence. Serum LDH and involvement of more than one extranodal site are independent risk factors for CNS recurrence in patients with large-cell lymphoma. The presence of both risk factors identifies a patient group at high risk for CNS recurrence. Established CNS recurrence can be rapidly fatal. Transient responses occur after radiation treatment.

Adult↗
PubMed1998

Current global status of carotid artery stent placement.

Our purpose was to review the current status of carotid artery stent placement throughout the world. Surveys were sent to major interventional centers in Europe, North and South America, and Asia. Information from peer-reviewed journals was also included and supplemented the survey. The survey asked various questions regarding the patients enrolled, procedure techniques, and results of carotid stenting, including complications and restenosis. Of the centers which were sent surveys, 24 responded. The total number of endovascular carotid stent procedures that have been performed worldwide to date included 2,048 cases, with a technical success of 98.6%. Complications that occurred during carotid stent placement or within a 30-day period following placement were recorded. Overall, there were 63 minor strokes, with a rate of occurrence of 3.08%. The total number of major strokes was 27, for a rate of 1.32%. There were 28 deaths within a 30-day postprocedure period, resulting in a mortality rate of 1.37%. Restenosis rates of carotid stenting have been 4.80% at 6 mo. Endovascular stent treatment of carotid artery atherosclerotic disease is growing as an alternative to vascular surgery, especially for patients that are at high risk for standard carotid endarterectomy. The periprocedural risks for major and minor strokes and death are generally acceptable at this early stage of development.

Angioplasty, Balloon↗
PubMed1998

Multiple analysis of a foodborne outbreak caused by infant formula contaminated by an atypical Salmonella virchow strain.

An outbreak of food poisoning involving most autonomous Spanish communities was detected in the first half of 1994. The causative food was infant formula milk contaminated by lactose-fermenting Salmonella virchow. It was not possible to isolate the causative strain from the manufacturer's facilities. During the same period of time, there was a significant increase in lactose-non-fermenting Salmonella virchow strains compared with the same period in previous years. Simultaneously, lactose-non-fermenting strains were recovered from clinical samples from children and from some milk samples that were involved in the outbreak. Therefore, it was speculated that the outbreak might be more extensive than initially thought. The following epidemiological markers were used for typing the Salmonella virchow strains involved in the outbreak: (i) phage typing: (ii) ribotyping, using a set of 20 different endonucleases: and (iii) pulsed-field gel electrophoresis, using three different endonucleases. The most useful markers for this serotype were phage typing and pulsed-field gel electrophoresis, since ribotyping was not able to distinguish all strains tested. The results obtained revealed that the outbreak was caused by at least two strains: one presenting phage type 4-4a and pulsed-field patterns A1 or A2 and L+ or L-, and another presenting phage type 2 and pulsed-field patterns A1 or A2 and L+ or L-. The results indicate that the outbreak was more extensive than initially thought and that the Virchow serotype is very clonal in Spain.

Animals↗
PubMed1998

Fatty acid desaturase activities and polyunsaturated fatty acid composition in human liver between the seventeenth and thirty-sixth gestational weeks.

OBJECTIVE: The aim of the study was to characterize n-3 and n-6 fatty acid delta5- and delta6-desaturase activities and their time course variations in human fetal liver between the 17th and 36th gestational week. STUDY DESIGN: Twenty-one biologic samples were obtained after legally approved medical abortion, according to French law. The desaturase activities were measured in the 21 liver samples by a radiochemical method by means of reverse-phase high-performance liquid chromatography. The fatty acid composition (percentage by weight) of liver phospholipids was assessed in 16 samples by gas-liquid chromatographic analysis. RESULTS: Both delta5- and delta6-desaturase activities were significantly expressed between the 17th and 36th gestational weeks. During the second trimester n-6 fatty acid delta5- and delta6-desaturase activities showed opposite patterns of variation; both then remained stable between the 25th and 36th weeks. Delta6-desaturation was higher in n-3 than n-6 fatty acids and peaked at the 18th gestational week. The percentages of linoleic and docosahexaenoic acids in liver microsomes were positively correlated with the gestation age (P < .01), whereas arachidonic acid remained stable. CONCLUSION: Significant n-3 and n-6 delta5- and delta6-desaturase activities are expressed in human fetal liver as early as the 17th gestational week and are stable throughout the third trimester. Their theoretic capacity evaluated from in vitro measurements appears lower than polyunsaturated fatty acid requirements and is not directly related to liver microsomal membrane fatty acid composition.

Arachidonic Acid↗
PubMed1998

Outcomes in anterior uveitis associated with the HLA-B27 haplotype.

OBJECTIVE: This study aimed to test the hypothesis that patients presenting with anterior uveitis who are HLA-B27 positive, either with or without associated systemic disease, have a less-favorable outcome than do patients with idiopathic anterior uveitis who are HLA-B27 negative. DESIGN: Retrospective case-controlled series. PARTICIPANTS: Ninety-seven patients who were HLA-B27 positive with no systemic disease, 94 patients who were HLA-B27 positive with systemic disease, and 72 patients who were HLA-B27 negative who presented with anterior uveitis were studied. MAIN OUTCOME MEASURES: Ocular complications (e.g., secondary glaucoma, cataract formation, pupillary synechiae, vitritis, cystoid macular edema, and optic disc edema), medical and surgical treatment, number of recurrent attacks, and final visual acuity were recorded for all patients. RESULTS: The patients who were HLA-B27 positive, either with or without systemic disease, experienced a greater number of complications than did the patients who were HLA-B27 negative. Periocular corticosteroids, systemic corticosteroids, and systemic immunosuppressive chemotherapy were required in a far greater number of HLA-B27-positive patients than in HLA-B27-negative patients (60% vs. 11%, 53% vs. 7%, and 18% vs. 1%, respectively; P < 0.001). The percentage of legally blind eyes was significantly greater in the HLA-B27-positive group, both with and without systemic disease, when compared with the HLA-B27-negative group (11% vs. 2%; P < 0.005). CONCLUSIONS: The prognosis of anterior uveitis associated with the HLA-B27 haplotype, either with or without associated systemic disease, is less favorable when compared with that of HLA-B27-negative patients with idiopathic anterior uveitis.

Adolescent↗
PubMed1998

Chromosomal sublocalization of the transcribed human telomere repeat binding factor 2 gene and comparative mapping in the mouse.

Telomere repeat binding factor 2 (TERF2) is one of two recently cloned mammalian telomere binding protein genes. TERF2 binds as a dimer with high affinity to the double-stranded TTAGGG telomeric repeat through an evolutionarily conserved myb-type DNA binding domain. TERF2 prevents telomere end-to-end fusion and may be important in maintaining genomic stability. We localized the transcribed TERF2 gene to human chromosome 16q22.1, tightly linked to the EST HUM000S343. The mouse Terf2 gene is situated by itself in a newly defined "bin" on chromosome 8 one crossover distal to Psm10 and Sntb2. Human TERF2 and mouse Terf2 are therefore part of a large evolutionarily conserved linkage group comprised of at least 25 known paralogous genes between human chromosome 16q and mouse chromosome 8.

Animals↗
PubMed1998

dRGS7 encodes a Drosophila homolog of EGL-10 and vertebrate RGS7.

We identified a Drosophila gene encoding a homolog of the regulator of G-protein signaling (RGS) protein family. This gene (dRGS7) is expressed in neurons of the embryo and adult fly and is predicted to encode a 428-amino acid protein with >55% overall amino acid sequence identity with the vertebrate protein RGS7 and the C. elegans EGL-10. The dRGS7 protein is 50% conserved in the C-terminal RGS domain with RGS7 and EGL-10 but, remarkably, displays much greater conservation with the N-terminal regions of these proteins. This finding implies a conserved function for these homologs from divergent species involving domains outside the RGS domain. The dRGS7 protein also has a domain of similarity with Dishevelled and pleckstrin, raising the possibility that these proteins interact with common signaling components.

Amino Acid Sequence↗
PubMed1998

Use of spiral computed tomography for the assessment of blunt trauma patients with potential aortic injury.

PURPOSE: The purpose of this study was to prospectively examine the accuracy of contrast-enhanced spiral thoracic computed tomography (CEST-CT) for direct detection of traumatic aortic injury resulting from blunt thoracic trauma. METHODS: During a 25-month period, all blunt trauma patients who had abnormal mediastinal contours on admission chest radiographs underwent CEST-CT. The presence and location of mediastinal blood and any direct signs of aortic injury, such as pseudoaneurysm, were recorded. Computed tomographic results were compared with results of aortography, when performed, surgery, or clinical status at discharge. RESULTS: There were 7,826 patients classified as having blunt trauma admitted during the study. Of these, 1,104 (14.3%) had CEST-CT performed. Mediastinal hemorrhage was detected on 118 (10.7%) of all thoracic computed tomographic scans. Direct evidence of aortic injury was detected in 24 patients (20.3%) with mediastinal hemorrhage and 2.2% of all patients undergoing CEST-CT. In this prospective series, CEST-CT was 100% sensitive based on clinical follow-up; it was 99.7% specific, with 89% positive and 100% negative predictive values and an overall diagnostic accuracy of 99.7%. CONCLUSION: CEST-CT is a valuable ancillary study for the detection of traumatic aortic injury. Spiral computed tomography is accurate for the detection and localization of both hemomediastinum and direct signs of aortic injury.

Acute Disease↗
PubMed1998

Comparative study of the use of poly(glycolic acid), calcium alginate and pluronics in the engineering of autologous porcine cartilage.

New cartilage formation has been successfully achieved by technology referred to as tissue engineering. Polymers and hydrogels such as poly(glycolic acid), calcium alginate, and poly(ethylene) and poly(propylene) hydrogels have been used as cell carriers to regenerate cartilage in the nude mouse model. The next step toward human applications of engineered cartilage is to demonstrate their potential in immunocompetent animal models. This study compared the suitability of three polymers for generating tissue engineered elastic cartilage using autologous cells in an immuno-competent porcine animal model. Auricular cartilage was obtained from pigs. Chondrocytes were isolated onto fiber based poly(glycolic acid) (PGA) scaffolds or suspended in calcium alginate or pluronic F127 gel at constant concentrations. Chondrocyte-polymer constructs were either implanted (PGA) or injected (calcium alginate and pluronic) as autologous implants subcutaneously into the pigs from which the cells had been isolated. Specimens were harvested and analyzed grossly and historically after 6 weeks in vivo. All explants demonstrated cartilage formation to a variable degree. When using PGA or calcium alginate, the overall histological appearance of the tissue formed is that of fibrocartilage with thick bundles of collagen dispersed in the tissue. When using pluronics as scaffold, histologic features resemble those of native elastic cartilage, showing a more organized arrangement of the cells, which seems to correlate to functional properties as elastin presence in the tissue engineered cartilage. Elastic cartilage engineered in an immunocompetent animal model varies with the type of polymer used. The behavior of the cell-polymer constructs is not fully understood and outcome seems to be related to several factors, including inflammatory reaction. Further studies with similar models are needed to determine the feasibility of engineering tissue generated from different cell-polymer constructs prior to human application.

Alginates↗
PubMed1998

High-dose chemotherapy for relapsed and refractory diffuse large B-cell lymphoma: mediastinal localization predicts for a favorable outcome.

PURPOSE: This study was performed to evaluate the outcome of high-dose chemotherapy and autologous transplantation in patients with diffuse B-cell large-cell lymphoma, and, specifically, to evaluate the impact of primary mediastinal localization on the outcome of high-dose chemotherapy. PATIENTS AND METHODS: A retrospective review was performed of all patients with diffuse large B-cell lymphoma who underwent autologous marrow or peripheral-blood stem-cell transplantation at our institution between January 1 986 and December 1995. RESULTS: Ninety patients were identified, of whom 31 (34%) had a primary mediastinal B-cell large-cell lymphoma (PML). Cumulative probabilities of disease-free survival, overall survival, and disease progression are 40% (95% confidence interval [CI], 29 to 51), 42% (95% CI, 31 to 53), and 52% (95% CI, 40 to 64), respectively. By univariate analysis, low lactate dehydrogenase (LDH) level and low Ann Arbor stage at transplant were associated with improved survival and disease-free survival. There was a trend for improved disease-free survival and survival for patients with PML. Multivariate stepwise Cox regression analysis showed that LDH level, Ann Arbor stage, and primary mediastinal localization were independent favorable prognostic factors for disease-free survival and survival. LDH level and Ann Arbor stage were also predictive for the risk of disease progression. CONCLUSION: Our results indicate that patients with PML may display an increased susceptibility to high-dose chemotherapy compared with other types of B-cell large-cell lymphoma. These findings, if confirmed, may have implications for the initial management of patients with PML.

Adolescent↗
PubMed1998

Hyper-CVAD and high-dose methotrexate/cytarabine followed by stem-cell transplantation: an active regimen for aggressive mantle-cell lymphoma.

PURPOSE: Diffuse and nodular forms of mantle-cell lymphoma (MCL) are consistently associated with poor prognosis. In an effort to improve the outcome, we adopted a treatment plan that consisted of four courses of fractionated cyclophosphamide (CY) 1,800 mg/m2 administered with doxorubicin (DOX), vincristine (VCR), and dexamethasone (Hyper-CVAD) that alternated with high-dose methotrexate (MTX) and cytarabine (Ara-C). After four courses, patients were consolidated with high-dose CY, total-body irradiation, and autologous or allogeneic blood or marrow stem-cell transplantation. PATIENTS AND METHODS: Forty-five patients were enrolled; 25 patients were previously untreated, 43 patients had Ann Arbor stage IV disease, and 42 patients had marrow involvement. Forty-one patients had diffuse histology, two patients had nodular, and two patients had blastic variants. RESULTS: Hyper-CVAD/MTX-Ara-C induced a response rate of 93.5% (complete response [CR], 38%; partial response [PR], 55.5%) after four cycles of pretransplantation induction chemotherapy. All patients who went on to undergo transplantation achieved CRs. For the 25 previously untreated patients, the overall survival (OS) and event-free survival (EFS) rates at 3 years were 92% (95% confidence interval [CI], 80 to 100) and 72% (95% CI, 45 to 98) compared with 25% (95% CI, 12 to 62; P = .005) and 17% (95% CI, 10 to 43; P = .007), respectively, for the previously treated patients. When compared with a historic control group who received a CY, DOX, VCR, and prednisone (CHOP)-like regimen, untreated patients in the study had a 3-year EFS rate of 72% versus 28% (P = .0001) and a better OS rate (92% v 56%; P = .05). Treatment-related death occurred in five patients: all were previously treated and two received allogeneic transplants. CONCLUSION: The Hyper-CVAD/MTX-Ara-C program followed by stem-cell transplantation is a promising new therapy for previously untreated patients with MCL.

Adult↗