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Biomedical subjects

A Rey

Publications and source records attributed to A Rey.

At least 55 records · Page 3Linked to original sources
PubMed2000

Thallium-201 scintigraphy is not predictive of late cardiac complications in patients with Hodgkin's disease treated with mediastinal radiation.

PURPOSE: To assess whether abnormalities depicted by Thallium-201 scintigraphy can predict the occurrence of late cardiac complications in patients with Hodgkin's disease treated with mantle field radiation therapy. METHODS AND MATERIALS: Thallium scintigraphy was performed in 49 patients at a median of 75 months after initial treatment (range 28-208 months). Initial treatment consisted in chemotherapy, given to two-thirds of the patients and mantle field radiation, delivered to all patients, using a 25-MV linear accelerator. Myocardial perfusion defects were observed in 78% of patients on thallium scintigraphy. These patients had their cardiac status reassessed at a median follow-up of 13.5 years after treatment. RESULTS: Forty-two patients were assessable, as data on the cardiac status were missing in 7 patients. The majority of patients received at least 40 Gy, and 75% of them were treated with one field per day. The median follow-up of patients is 13.5 years (range 9-24.5). Eleven cardiac complications were observed in 9 patients (coronary artery disease [n = 2], conduction-system abnormalities [n = 3], valvular defects [n = 5], and congestive heart disease [n = 1]). The median 15-year actuarial incidence of cardiac complications was 21% (95% confidence interval of 9-40%). The positive and negative predictive value of thallium scintigraphy was 19% and 77%, respectively. The univariate analysis showed that the extent of left ventricle exposure to irradiation was an adverse prognostic factor, and chemotherapy administered before mantle field irradiation was of borderline significance. CONCLUSION: Thallium scintigraphy is not predictive of late cardiac complications. The extent of left ventricle exposure to radiation and possibly chemotherapy given before radiation treatment are adverse prognostic factors.

Adolescent↗
PubMed2000

Synthesis and characterization of mixed-ligand oxorhenium complexes with the SNN type of ligand. Isolation of a novel ReO[SN][S][S] complex.

A new series of mixed-ligand oxorhenium complexes 4-9, with ligands 1-3 (L1H2) containing the SNN donor set and monodentate thiols as coligands (L2H), is reported. All complexes were synthesized using ReOCl3(PPh3)2 as precursor. They were isolated as crystalline products and characterized by elemental analysis and IR and NMR spectroscopy. The ligands 1 and 2 (general formula RCH2CH2NHCH2CH2SH, where R = N(C2H5)2 in 1 and pyrrolidin-1-yl in 2) act as tridentate SNN chelates to the ReO3+ core, leaving one open coordination site cis to the oxo group. The fourth coordination site is occupied by a monodentate aromatic thiol which acts as a coligand. Thus, three new "3 + 1" [SNN][S] oxorhenium complexes 4-6 (general formula ReO[RCH2CH2NCH2CH2S][SX], where R = N(C2H5)2 and X = phenyl in 4, R = N(C2H5)2 and X = p-methylphenyl in 5, and R = pyrrolidinlyl and X = p-methylphenyl in 6) were prepared in high yield. Complex 4 adopts an almost perfect square pyramidal geometry (tau = 0.07), while 6 forms a distorted square pyramidal geometry (tau = 0.24). In both complexes 4 and 6, the basal plane is formed by the SNN donor set of the tridentate ligand and the S of the monodentate thiol. On the other hand, the ligand 3, [(CH3)2CH]2NCH2CH2NHCH2CH2SH, acts as a bidentate ligand, probably due to steric hindrance, and it coordinates to the ReO3+ core through the SN atoms, leaving two open coordination sites cis to the oxo group. These two vacant positions are occupied by two molecules of the monodentate thiol coligand, producing a novel type of "2 + 1 + 1" [SN][S][S] oxorhenium mixed-ligand complexes 7-9 (general formula ReO[[(CH3)2CH]2NCH2CH2NHCH2CH2S][SX][SX], where X = phenyl in 7, p-methylphenyl in 8, and benzyl in 9). The coordination sphere about rhenium in 7 and 8 consists of the SN donor set of ligand 3, two sulfurs of the two monodentate thiols, and the doubly bonded oxygen atom in a trigonally distorted square pyramidal geometry (tau = 0.44 and 0.45 for 7 and 8, respectively). Detailed NMR assignments were determined for complexes 5 and 8.

Journal Article↗
PubMed2000

Increased cyclooxygenase-2 and 5-lipoxygenase activating protein expression in peritoneal macrophages during ovalbumin immunization of mice and cytosolic phospholipase A(2) activation after antigen challenge.

The present study investigates phenotypic and functional differentiation of peritoneal macrophages during ovalbumin-induced subcutaneous immunization of mice. For the first time we show that, in mouse peritoneal macrophages, ovalbumin immunization induces an increase in cyclooxygenase-2 (COX-2) and 5-lipoxygenase activating protein (FLAP) expression whereas it inhibits cytosolic phospholipase A(2) (cPLA2) expression. The study of arachidonic acid (AA) metabolism in peritoneal macrophages from control (cPM) and ovalbumin-immunized (iPM) mice shows that the reduced cPLA2 expression is correlated to a reduced basal AA metabolism, but is not a limiting factor for the opsonized zymosan-, PMA-, or A23187-triggered AA metabolism. We also show that in vitro ovalbumin challenge induces, only in iPM, cPLA2 activation through phosphorylation of serine residues, via a mechanism involving MAP kinases, and through increased intracellular calcium concentrations, leading to eicosanoid production. In parallel, we report that, in peritoneal macrophages, ovalbumin immunization induces the expression of CD23, the low affinity receptor for IgEs known for its involvement in allergic diseases. Thus, the modified expression of the enzymes involved in AA metabolism and the difference of response of cPM and iPM toward the antigen are important elements to understand the underlying mechanisms of ovalbumin-induced allergic responses.

5-Lipoxygenase-Activating Proteins↗
PubMed2000

An extended study of heavy metal deposition in Galicia (NW Spain) based on moss analysis.

This paper describes the first attempt to determine the levels of heavy metal contamination in Galicia (NW Spain) by analysis of moss species. Samples of Scleropodium purum and Hypnum cupressiforme were collected from 75 sites, in 1995 and 1997, and analysed by atomic absorption spectrophotometry and atomic fluorescence for Al, As, Co, Cr, Cu, Fe, Hg, Ni, Pb and Zn. Comparisons were made between the two moss species used and, for those elements present at different concentrations in the two species, regression lines were made for interspecies calibration. Distribution maps were drawn up for each of the elements according to their concentration in the moss. In certain areas it was possible to relate deposition to the existence of known sources of contamination. The study demonstrates that the highest levels of elements were found in the most heavily industrialised and populated areas. Concentrations of As, Cu, Hg and Ni, recorded during the 1997 sampling were significantly higher than those found in 1995, possibly due to agricultural and industrial activities.

Agriculture↗
PubMed2000

Graphemes are perceptual reading units.

Graphemes are commonly defined as the written representation of phonemes. For example, the word 'BREAD' is composed of the four phonemes /b/, /r/, /e/ and /d/, and consequently, of the four graphemes 'B', 'R', 'EA', and 'D'. Graphemes can thus be considered the minimal 'functional bridges' in the mapping between orthography and phonology. In the present study, we investigated the hypothesis that graphemes are processed as perceptual units by the reading system. If the reading system processes graphemes as units, then detecting a letter in a word should be harder when this letter is embedded in a multi-letter grapheme than when it corresponds to a single-letter grapheme. In Experiment 1A, done in English, participants were slower to detect a target letter in a word when the target letter was embedded in multi-letter grapheme (i.e. 'A' in 'BEACH') than when it corresponded to a single-letter grapheme (i.e. 'A' in 'PLACE'). In Experiment 1B, this effect was replicated in French. In Experiment 2, done in English, this grapheme effect remained when phonemic similarity between the target letter alone and the target letter inside the word was controlled. Together, the results are consistent with the assumption that graphemes are processed as perceptual reading units in alphabetic writing systems such as English or French.

Humans↗
PubMed2000

Analysis of clinicopathologic prognostic factors for 157 uterine sarcomas and evaluation of a grading score validated for soft tissue sarcoma.

BACKGROUND: Uterine sarcomas (US) are rare and carry a poor prognosis characterized by high rates of local recurrence and metastasis. The aim of this study was to test, for what the authors believe was the first time with US, the prognostic impact of the histologic grade validated by the French Federation of Anticancer Centers (FNCLCC) for soft tissue sarcomas (STS). The grade is the sum of the scores allocated for three major histologic criteria: tumor differentiation, mitotic count, and tumor necrosis. Other histologic and clinical factors were tested as well. METHODS: The study included 157 patients in whom 78 leiomyosarcomas (LMS), 52 malignant mixed müllerian tumors (MMMT), and 27 endometrial stroma sarcomas (ESS) were documented. RESULTS: The median follow-up was 54 months (range, 6-230 months). The median OS and EFS were 33 and 13 months, respectively. The FNCLCC grade validated in soft tissue sarcomas was not a prognostic factor for survival or relapse for any of the US histologic subtypes. For LMS, stage and mitotic count were the only factors that had an influence on survival and relapse. For MMMT, stage and age were the only prognostic factors, and none of the histologic criteria impacted on the outcome. For ESS, the grade defined by Norris and Taylor was an important prognostic factor, particularly for survival. CONCLUSIONS: The FNCLCC grading score could not be used as a prognostic indicator for uterine sarcomas. The diagnosis of US is in itself an unfavorable prognostic factor, except when the diagnosis is low grade ESS.

Adult↗
PubMed2000

Complete necrosis induced by preoperative chemotherapy in Wilms tumor as an indicator of low risk: report of the international society of paediatric oncology (SIOP) nephroblastoma trial and study 9.

BACKGROUND: The SIOP Nephroblastoma therapeutic protocols include a period of preoperative chemotherapy followed by nephrectomy and a period of postoperative chemotherapy. From the outset, identification of low-risk groups has been an aim of the SIOP Nephroblastoma Trials and Studies. Now that 90% of children with Wilms tumor can be cured, attention is even more focused on the identification of patients who could benefit from less aggressive postoperative therapy, thus minimizing the morbidity and late effects associated with treatment. The prognostic implications of total necrosis in nephroblastoma after chemotherapy have not been investigated hitherto. PROCEDURE: Between November 1, 1987 and June 30, 1993, 599 patients referred to the SIOP-9 Nephroblastoma Trial and Study were preoperatively treated and classified as stages I-IV nonanaplastic Wilms tumor. RESULTS: Of these 599 patients, pathologic examination of the nephrectomy specimen revealed a completely necrotic Wilms tumor (CNWT) with no viable tumor remaining in 59 (10%): these comprised 37 stages I-III and 22 stage IV. Of these patients, 58 (98%) had no evidence of disease at 5 years vs. 90% for the rest of the cohort (P < 0.05). Stages I-III patients represented 63% of CNWT and had a 97% overall survival rate. The only death was related to veno-occlusive disease and occurred in a stage I patient in the month following nephrectomy. Stage IV patients represented 37% of CNWT (vs. only 10% of all other cases of unilateral nonanaplastic Wilms tumor) and had a 100% rate of survival. Children with CNWT were older (mean 59 months vs. 43 months); their tumor at diagnosis was larger and had regressed more significantly at subsequent ultrasound examination. The data also uphold the hypothesis that Wilms tumors of blastemic pattern are most aggressive, but also are extremely responsive to chemotherapy. CONCLUSIONS: Patients with unilateral nonanaplastic WT that showed total necrosis following preoperative chemotherapy had excellent outcome and should benefit from less aggressive postoperative treatment in further trials. Other very responsive tumors, such as Wilms with <10% viable tumor, should also be assessed.

Adolescent↗
PubMed2000

Ovarian transposition for patients with cervical carcinoma treated by radiosurgical combination.

OBJECTIVE: To assess the indications, effectiveness, and complications of ovarian transposition before pelvic irradiation for cervical cancer. DESIGN: Prospective study. SETTING: Gynecologic oncology department at a French cancer center. PATIENT(S): One hundred seven patients treated for cervical cancer. INTERVENTION(S): Ovarian transposition to the paracolic gutters with radical hysterectomy and lymphadenectomy. MAIN OUTCOME MEASURE(S): Clinical and laboratory follow-up tests for ovarian function. RESULT(S): Bilateral ovarian transposition was achieved in 104 patients (98%). Twelve patients were lost to follow-up or excluded because of evolution of the disease. Preservation of ovarian function was achieved in 83% of the patients having follow-up. The rates of ovarian preservation were 100% for patients treated exclusively by surgery, 90% for patients treated by postoperative vaginal brachytherapy, and 60% for patients treated by postoperative external radiation therapy and vaginal brachytherapy. The main risk for ovarian failure was found in patients treated by external radiation therapy. CONCLUSION(S): Ovarian transposition is a safe and effective procedure for preserving ovarian function in patients treated by a radiosurgical combination. This procedure should be performed in patients <40 years of age with a small invasive cervical carcinoma (<3 cm) treated by initial surgery. In such selected cases, the risk of ovarian metastasis is low.

Abdominal Pain↗
PubMed2000

Perinatal toxicology of Ruta chalepensis (Rutaceae) in mice.

Dried leaf infusions of Ruta chalepensis L. (Rutaceae), 'rue', 'ruda', were found to cause perinatal changes in mice, at daily doses of 0.16, 0.80 and 1.60 g/kg, administered p.o. from 1 to 14 days post coitum. Significant decreases in the appearance time of physical signs, righting reflex and cliff avoidance together with minus scores in string test and swimming ability were observed. Moreover, histological studies showed progressive angiogenic development on placenta blood supply and weakness at blood barrier in brain, thymus and pery-lymph vestibule. We found out that the results tend to confirm the embryotoxic effect of the plant and its harmful use.

Animals↗
PubMed2000

Visual and phonological codes in letter and word recognition: evidence from incremental priming.

Critical issues in letter and word priming were investigated using the novel incremental priming technique. This technique adds a parametric manipulation of prime duration (or prime intensity) to the traditional design of a fast masked priming study. By doing so, additional information on the time course and nature of priming effects can be obtained. In Experiment 1, cross-case letter priming (a-A) was investigated in both alphabetic decision (letter/non-letter classification) and letter naming. In Experiment 2, cross-case word priming was investigated in lexical decision and naming. Whereas letter priming in alphabetic decision was most strongly determined by visual overlap between prime and target, word priming in lexical decision was facilitated by both orthographic and phonological information. Orthographic activation was stronger and occurred earlier than phonological activation. In letter and word naming, in contrast, priming effects were most strongly determined by phonological/articulatory information. Differences and similarities between letter and word recognition are discussed in the light of the incremental priming data.

Adult↗
PubMed2000

Testing a process-based model of tree seedling growth by manipulating.

A model was developed that simulated photosynthesis, growth and allocation in tree seedlings. The model was parameterized with data from experiments on seedlings of sycamore (Acer pseudoplatanus L.), Sitka spruce (Picea sitchensis (Bong) Carr.) and young birch trees (Betula pendula Roth.). In these experiments, CO2 concentration ([CO2]) and nutrient addition rate were varied. Parameters quantifying nutrient uptake, translocation and starch synthesis were fitted, based on data from control treatments. Elevated [CO2] and low-nutrient treatments were then used to test the predicted response of growth and allocation against observations. The model accurately predicted total seedling growth in the elevated [CO2] treatments. A response of growth to elevated [CO2] was seen in the birch and sycamore experiments, but not in the Sitka spruce, because of photosynthetic down-regulation. Predictions of allocation were reasonably accurate in the birch and Sitka spruce experiments, but were notably poorer in the sycamore experiments, possibly because of differences in sink strength between root and shoot. In the birch and sycamore experiments, little change in allocation with elevated [CO2] was observed or predicted. This was ascribed to the relative values of K(Tc) and K(Tn), the translocation coefficients that determine the sensitivity of allocation to carbon and nitrogen uptake rates, respectively. Growth and allocation in the low-nutrient treatments were poorly predicted by the model. In Sitka spruce, it was suspected that the photosynthetic parameters measured in August 1994 had been higher earlier in the season, before nutrients became depleted. In sycamore, the discrepancies were thought to relate to differences in sink strength between root and shoot that could not be described by the model.

Carbon Dioxide↗
PubMed2000

Tirapazamine plus cisplatin versus cisplatin in advanced non-small-cell lung cancer: A report of the international CATAPULT I study group. Cisplatin and Tirapazamine in Subjects with Advanced Previously Untreated Non-Small-Cell Lung Tumors.

PURPOSE: A phase III trial, Cisplatin and Tirapazamine in Subjects with Advanced Previously Untreated Non-Small-Cell Lung Tumors (CATAPULT I), was designed to determine the efficacy and safety of tirapazamine plus cisplatin for the treatment of non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients with previously untreated NSCLC were randomized to receive either tirapazamine (390 mg/m(2) infused over 2 hours) followed 1 hour later by cisplatin (75 mg/m(2) over 1 hour) or 75 mg/m(2) of cisplatin alone, every 3 weeks for a maximum of eight cycles. RESULTS: A total of 446 patients with NSCLC (17% with stage IIIB disease and pleural effusions; 83% with stage IV disease) were entered onto the study. Karnofsky performance status (KPS) was >/= 60 for all patients (for 10%, KPS = 60; for 90%, KPS = 70 to 100). Sixty patients (14%) had clinically stable brain metastases. The median survival was significantly longer (34.6 v 27. 7 weeks; P =.0078) and the response rate was significantly greater (27.5% v 13.7%; P <.001) for patients who received tirapazamine plus cisplatin (n = 218) than for those who received cisplatin alone (n = 219). The tirapazamine-plus-cisplatin regimen was associated with mild to moderate adverse events, including acute, reversible hearing loss, reversible, intermittent muscle cramping, diarrhea, skin rash, nausea, and vomiting. There were no incremental increases in myelosuppression, peripheral neuropathy, or renal, hepatic, or cardiac toxicity and no deaths related to tirapazamine. CONCLUSION: The CATAPULT I study shows that tirapazamine enhances the activity of cisplatin in patients with advanced NSCLC and confirms that hypoxia is an exploitable therapeutic target in human malignancies.

Adult↗
PubMed2000

Laboratory and field evaluation of metallic copper on Aedes albopictus (Diptera: Culicidae) larval development.

Laboratory bioassays and field trials were carried out to study the effect of metallic copper on the development of Aedes albopictus (Skuse). Multiwire electric cable was used as a source of metallic copper. Three different doses were used in laboratory tests (5, 10, and 20 g/liter) and two in field tests (20 and 40 g/liter). In the laboratory, 10 g/liter induced high mortality and a lack of development in Ae. albopictus larvae and doses of 20 g/liter completely inhibited development. Larval mortality was higher in earlier instars than in third through fourth instars and pupae. No effects were reported on egg hatching. Copper ion concentration in water increased up to 574 ppb for 5 g/liter dose, 710 ppb for 10 g/liter dose, and 1,210 ppb for 20 g/liter dose, within week 6. The increasing concentration of copper in water was correlated positively with the decreasing production of adults. Copper ions concentration < 500 ppb did not or only slightly affected larval development and mortality of Ae. albopictus in laboratory tests. Copper concentrations between 500 and 1,000 ppb delayed larval development and caused high mortality. Copper concentrations > 1,000 ppb inhibited larval development completely killing all the larvae. This last result has been achieved by the use of a 20 g/liter dose of metallic copper in water. Copper also affected adult weight. In field trials, 20 g/liter reduced the number of larvae in treated pots by 90%, and 40 g/liter completely prevented oviposition. Moreover, the persistence of the toxic action of metallic copper in the field lasted for several months.

Aedes↗
PubMed2000

[Endolymphatic sac tumor: a rare tumor of internal ear. Report of two cases].

Papillary tumors of the temporal bone are rare and aggressive neoplasms. Recently described, these tumors had initially a presumed middle-ear origin. Only recently, convincing anatomic, morphological and immunohistochemical arguments exist for an endolymphatic sac origin (inner-ear origin). We report two cases of endolymphatic sac tumor. These tumors can be encountered sporadically or in Von Hippel-Lindau disease. They classically grow very slowly, resulting in late clinical manifestations with expansive mass invading temporal bone and extending in posterior fossa. Radiologically, these endolymphatic sac tumors can mimic metastatic carcinoma, paraganglioma, or cerebellar haemangioblastoma specially in von Hippel-Lindau disease. Histology shows a papillary epithelial tumor with hypervascular stroma, without atypia. The treatment for these tumors is surgical and curative when early diagnosed. In apparently sporadic cases, genetic analysis for Von Hippel-Lindau disease should be considered.

Adult↗
PubMed2000

[Clinical application of the multichannel auditory brainstem implant].

OBJECTIVE: To investigate the surgical techniques and speech performance of multichannel auditory brainstem implant (ABI) in patients with bilateral acoustic neuromas (neurofibromatosis type 2). METHODS: The nucleus 21 channel auditory brainstem implant was implanted into the lateral recess of the fourth ventricle through the translabyrinthine approach in 7 patients after removal of the tumor. The accurate placement of electrode array was ensured by the electromyogram monitoring of the 7th and 9th nerves and the electrically evoked auditory brainstem responses (EABR). Initial switch-on occurred six weeks postoperatively. Speech evaluation was performed every 3 months for the first year and annually thereafter. RESULTS: During the surgery, the lateral recess could be found and the typical EABR could be recorded in 6 cases. They later reported a significant benefit from the device. Two of the cases have achieved functional open-set speech understanding. In contrast, one patient with no EABR because of difficulty of the anatomic location during the surgery had no sensations postoperatively. CONCLUSION: The multichannel ABI could effectively restore auditory sensations in patients deafened by bilateral acoustic neuromas. The accurate location of the cochlear nucleus complex during surgery was the key factor for the success of the operation.

Adolescent↗