391 resultados para Centrally
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Background In a previous study, the European Organisation for Research and Treatment of Cancer (EORTC) reported a scoring system to predict survival of patients with low-grade gliomas (LGGs). A major issue in the diagnosis of brain tumors is the lack of agreement among pathologists. New models in patients with LGGs diagnosed by central pathology review are needed. Methods Data from 339 EORTC patients with LGGs diagnosed by central pathology review were used to develop new prognostic models for progression-free survival (PFS) and overall survival (OS). Data from 450 patients with centrally diagnosed LGGs recruited into 2 large studies conducted by North American cooperative groups were used to validate the models. Results Both PFS and OS were negatively influenced by the presence of baseline neurological deficits, a shorter time since first symptoms (<30 wk), an astrocytic tumor type, and tumors larger than 5 cm in diameter. Early irradiation improved PFS but not OS. Three risk groups have been identified (low, intermediate, and high) and validated. Conclusions We have developed new prognostic models in a more homogeneous LGG population diagnosed by central pathology review. This population better fits with modern practice, where patients are enrolled in clinical trials based on central or panel pathology review. We could validate the models in a large, external, and independent dataset. The models can divide LGG patients into 3 risk groups and provide reliable individual survival predictions. Inclusion of other clinical and molecular factors might still improve models' predictions.
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AimTo identify the bioclimatic niche of the endangered Andean cat (Leopardus jacobita), one of the rarest and least known felids in the world, by developing a species distribution model.LocationSouth America, High Andes and Patagonian steppe. Peru, Bolivia, Chile, Argentina.MethodsWe used 108 Andean cat records to build the models, and 27 to test them, applying the Maxent algorithm to sets of uncorrelated bioclimatic variables from global databases, including elevation. We based our biogeographical interpretations on the examination of the predicted geographic range, the modelled response curves and latitudinal variations in climatic variables associated with the locality data.ResultsSimple bioclimatic models for Andean cats were highly predictive with only 3-4 explanatory variables. The climatic niche of the species was defined by extreme diurnal variations in temperature, cold minimum and moderate maximum temperatures, and aridity, characteristic not only of the Andean highlands but also of the Patagonian steppe. Argentina had the highest representation of suitable climates, and Chile the lowest. The most favourable conditions were centrally located and spanned across international boundaries. Discontinuities in suitable climatic conditions coincided with three biogeographical barriers associated with climatic or topographic transitions.Main conclusionsSimple bioclimatic models can produce useful predictions of suitable climatic conditions for rare species, including major biogeographical constraints. In our study case, these constraints are also known to affect the distribution of other Andean species and the genetic structure of Andean cat populations. We recommend surveys of areas with suitable climates and no Andean cat records, including the corridor connecting two core populations. The inclusion of landscape variables at finer scales, crucially the distribution of Andean cat prey, would contribute to refine our predictions for conservation applications.
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BACKGROUND AND PURPOSE: The EORTC 22043-30041 trial investigates the role of the addition of androgen suppression to post-operative radiotherapy in patients who have undergone radical prostatectomy. As part of the quality assurance of radiotherapy (QART) a Dummy Run (DR) procedure was performed. MATERIALS AND METHOD: The protocol included detailed and published delineation guidelines. Participating institutions digitally submitted radiotherapy treatment volumes and a treatment plan for a standard clinical case. Submissions were centrally reviewed using the VODCA software platform. RESULTS: Thirty-eight submissions from thirty-one institutions were reviewed. Six were accepted without comments. Twenty-three were accepted with comments on one or more items: target volume delineation (22), OAR delineation (23), planning and dosimetry (3) or treatment verification (1). Nine submissions were rejected requiring resubmission, seven for target volume delineation reasons alone. Intervention to highlight the importance of delineation guidelines was made prior to the entry of the first patient in the trial. After this, a lower percentage of resubmissions was required. CONCLUSIONS: The EORTC 22043-30041 Dummy Run highlights the need for timely and effective QART in clinical trials. The variation in target volume and OAR definition demonstrates that clinical guidelines and radiotherapy protocols are not a substitute for QART procedures. Early intervention in response to the Dummy Run improved protocol understanding.
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The state of Vaud model of the pre-hospital chain of survival is an example of an efficient way to deal with pre-hospital emergencies. It revolves around a centrally located dispatch center managing emergencies according to specific key words, allowing dispatchers to send out resources among which we find general practitioners, ambulances, physician staffed fast response cars or physician staffed helicopters and specific equipment. The Vaud pre-hospital chain of survival has been tailored according to geographical, demographical and political necessities. It undergoes constant reassessment and needs continuous adaptations to the ever changing demographics and epidemiology of pre-hospital medicine.
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The goal of this paper is to present an optimal resource allocation model for the regional allocation of public service inputs. Theproposed solution leads to maximise the relative public service availability in regions located below the best availability frontier, subject to exogenous budget restrictions and equality ofaccess for equal need criteria (equity-based notion of regional needs). The construction of non-parametric deficit indicators is proposed for public service availability by a novel application of Data Envelopment Analysis (DEA) models, whose results offer advantages for the evaluation and improvement of decentralised public resource allocation systems. The method introduced in this paper has relevance as a resource allocation guide for the majority of services centrally funded by the public sector in a given country, such as health care, basic and higher education, citizen safety, justice, transportation, environmental protection, leisure, culture, housing and city planning, etc.
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Tolperisone (Mydocalm) is a centrally acting muscle relaxant with few sedative side effects that is used for the treatment of chronic pain conditions. We describe three cases of suicidal tolperisone poisoning in three healthy young subjects in the years 2006, 2008 and 2009. In all cases, macroscopic and microscopic autopsy findings did not reveal the cause of death. Systematic toxicological analysis (STA) including immunological tests, screening for volatile substances and blood, urine and gastric content screening by GC-MS and HPLC-DAD demonstrated the presence of tolperisone in all cases. In addition to tolperisone, only the analgesics paracetamol (acetaminophen), ibuprofen and naproxen could be detected. The blood ethanol concentrations were all lower than 0.10 g/kg. Tolperisone was extracted by liquid-liquid extraction using n-chlorobutane as the extraction solvent. The quantification was performed by GC-NPD analysis of blood, urine and gastric content. Tolperisone concentrations of 7.0 mg/l, 14 mg/l and 19 mg/l were found in the blood of the deceased. In the absence of other autopsy findings, the deaths in these three cases were finally explained as a result of lethal tolperisone ingestion. To the best of our knowledge, these three cases are the first reported cases of suicidal tolperisone poisonings.
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BACKGROUND: Concomitant chemoradiotherapy and accelerated radiotherapy independently improve outcomes for patients with locally advanced head and neck squamous-cell carcinoma (HNSCC). We aimed to assess the efficacy and safety of a combination of these approaches. METHODS: In our open-label phase 3 randomised trial, we enrolled patients with locally advanced, stage III and IV (non-metastatic) HNSCC and an Eastern Cooperative Oncology Group performance status of 0-2. We randomly allocated patients centrally with a computer program (with centre, T stage, N stage, and localisation as minimisation factors) in a 1:1:1 ratio to receive conventional chemoradiotherapy (70 Gy in 7 weeks plus three cycles of 4 days' concomitant carboplatin-fluorouracil), accelerated radiotherapy-chemotherapy (70 Gy in 6 weeks plus two cycles of 5 days' concomitant carboplatin-fluorouracil), or very accelerated radiotherapy alone (64·8 Gy [1·8 Gy twice daily] in 3·5 weeks). The primary endpoint, progression-free survival (PFS), was assessed in all enrolled patients. This trial is completed. The trial is registered with ClinicalTrials.gov, number NCT00828386. FINDINGS: Between Feb 29, 2000, and May 9, 2007, we randomly allocated 279 patients to receive conventional chemoradiotherapy, 280 to accelerated radiotherapy-chemotherapy, and 281 to very accelerated radiotherapy. Median follow-up was 5·2 years (IQR 4·9-6·2); rates of chemotherapy and radiotherapy compliance were good in all groups. Accelerated radiotherapy-chemotherapy offered no PFS benefit compared with conventional chemoradiotherapy (HR 1·02, 95% CI 0·84-1·23; p=0·88) or very accelerated radiotherapy (0·83, 0·69-1·01; p=0·060); conventional chemoradiotherapy improved PFS compared with very accelerated radiotherapy (0·82, 0·67-0·99; p=0·041). 3-year PFS was 37·6% (95% CI 32·1-43·4) after conventional chemoradiotherapy, 34·1% (28·7-39·8) after accelerated radiotherapy-chemotherapy, and 32·2% (27·0-37·9) after very accelerated radiotherapy. More patients in the very accelerated radiotherapy group had RTOG grade 3-4 acute mucosal toxicity (226 [84%] of 268 patients) compared with accelerated radiotherapy-chemotherapy (205 [76%] of 271 patients) or conventional chemoradiotherapy (180 [69%] of 262; p=0·0001). 158 (60%) of 265 patients in the conventional chemoradiotherapy group, 176 (64%) of 276 patients in the accelerated radiotherapy-chemotherapy group, and 190 (70%) of 272 patients in the very accelerated radiotherapy group were intubated with feeding tubes during treatment (p=0·045). INTERPRETATION: Chemotherapy has a substantial treatment effect given concomitantly with radiotherapy and acceleration of radiotherapy cannot compensate for the absence of chemotherapy. We noted the most favourable outcomes for conventional chemoradiotherapy, suggesting that acceleration of radiotherapy is probably not beneficial in concomitant chemoradiotherapy schedules. FUNDING: French Ministry of Health.
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Ripglut1;glut2-/- mice have no endogenous glucose transporter type 2 (glut2) gene expression but rescue glucose-regulated insulin secretion. Control of glucagon plasma levels is, however, abnormal, with fed hyperglucagonemia and insensitivity to physiological hypo- or hyperglycemia, indicating that GLUT2-dependent sensors control glucagon secretion. Here, we evaluated whether these sensors were located centrally and whether GLUT2 was expressed in glial cells or in neurons. We showed that ripglut1;glut2-/- mice failed to increase plasma glucagon levels following glucoprivation induced either by i.p. or intracerebroventricular 2-deoxy-D-glucose injections. This was accompanied by failure of 2-deoxy-D-glucose injections to activate c-Fos-like immunoreactivity in the nucleus of the tractus solitarius and the dorsal motor nucleus of the vagus. When glut2 was expressed by transgenesis in glial cells but not in neurons of ripglut1;glut2-/- mice, stimulated glucagon secretion was restored as was c-Fos-like immunoreactive labeling in the brainstem. When ripglut1;glut2-/- mice were backcrossed into the C57BL/6 genetic background, fed plasma glucagon levels were also elevated due to abnormal autonomic input to the alpha cells; glucagon secretion was, however, stimulated by hypoglycemic stimuli to levels similar to those in control mice. These studies identify the existence of central glucose sensors requiring glut2 expression in glial cells and therefore functional coupling between glial cells and neurons. These sensors may be activated at different glycemic levels depending on the genetic background.
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Aim: To compare a less intensive regimen based on high-dose imatinib (IM) to an intensive IM/HyperCVAD regimen in adults with Ph+ ALL, in terms of early response and outcome after stem cell transplantation (SCT). Methods: Patients aged 18-60 years with previously untreated Ph+ ALL not evolving from chronic myeloid leukemia were eligible if no contra-indication to chemotherapy and SCT (ClinicalTrials.gov ID, NCT00327678). After a steroid prephase allowing Ph and/or BCR-ABL diagnosis, cycle 1 differed between randomization arms. In arm A (IM-based), IM was given at 800 mg on day 1-28, combined with vincristine (2 mg, day 1, 8, 15, 22) and dexamethasone (40 mg, day 1-2, 8-9, 15-16, and 22-23) only. In arm B (IM/HyperCVAD), IM was given at 800 mg on day 1-14, combined with adriamycin (50 mg/m2, day 4), cyclophosphamide (300 mg/m2/12h, day 1, 2, 3), vincristine (2 mg, day 4 and 11), and dexamethasone (40 mg, day 1-4 and 11-14). All patients received a cycle 2 combining high-dose methotrexate (1 g/m2, day 1) and AraC (3 g/m2/12h, day 2 and 3) with IM at 800 mg on day 1-14, whatever their response. Four intrathecal infusions were given during this induction/consolidation period. Minimal residual disease (MRD) was centrally evaluated by quantitative RQ-PCR after cycle 1 (MRD1) and cycle 2 (MRD2). Major MRD response was defined as BCR-ABL/ABL ratio <0.1%. Then, all patients were to receive allogeneic SCT using related or unrelated matched donor stem cells or autologous SCT if no donor and a major MRD2 response. IM/chemotherapy maintenance was planned after autologous SCT. In the absence of SCT, patients received alternating cycles 1 (as in arm B) and cycles 2 followed by maintenance, like in the published IM/HyperCVAD regimen. The primary objective was non-inferiority of arm A in term of major MRD2 response. Secondary objectives were CR rate, SCT rate, treatment- and transplant-related mortality, relapse-free (RFS), event-free (EFS) and overall (OS) survival. Results: Among the 270 patients randomized between May 2006 and August 2011, 265 patients were evaluable for this analysis (133 arm A, 132 arm B; median age, 47 years; median follow-up, 40 months). Main patient characteristics were well-balanced between both arms. Due to higher induction mortality in arm B (9 versus 1 deaths; P=0.01), CR rate was higher in the less intensive arm A (98% versus 89% after cycle 1 and 98% versus 91% after cycle 2; P= 0.003 and 0.006, respectively). A total of 213 and 205 patients were evaluated for bone marrow MRD1 and MRD2. The rates of patients reaching major MRD response and undetectable MRD were 45% (44% arm A, 46% arm B; P=0.79) and 10% (in both arms) at MRD1 and 66% (68% arm A, 63.5% arm B; P=0.56) and 25% (28% arm A, 22% arm B; P=0.33) at MRD2, respectively. The non-inferiority primary endpoint was thus demonstrated (P= 0.002). Overall, EFS was estimated at 42% (95% CI, 35-49) and OS at 51% (95% CI, 44-57) at 3 years, with no difference between arm A and B (46% versus 38% and 53% versus 49%; P=0.25 and 0.61, respectively). Of the 251 CR patients, 157 (80 arm A, 77 arm B) and 34 (17 in both arms) received allogeneic and autologous SCT in first CR, respectively. Allogeneic transplant-related mortality was similar in both arms (31.5% versus 22% at 3 years; P=0.51). Of the 157 allografted patients, 133 had MRD2 evaluation and 89 had MRD2 <0.1%. In these patients, MRD2 did not significantly influence post-transplant RFS and OS, either when tested with the 0.1% cutoff or as a continuous log covariate. Of the 34 autografted patients, 31 had MRD2 evaluation and, according to the protocol, 28 had MRD2 <0.1%. When restricting the comparison to patients achieving major MRD2 response and with the current follow-up, a trend for better results was observed after autologous as compared to allogeneic SCT (RFS, 63% versus 49.5% and OS, 69% versus 58% at 3 years; P=0.35 and P=0.08, respectively). Conclusions: In adults, the use of TK inhibitors (TKI) has markedly improved the results of Ph+ ALL therapy, now close to those observed in Ph-negative ALL. We demonstrated here that chemotherapy intensity may be safely reduced when associated with high-dose IM. We will further explore this TKI-based strategy using nilotinib prior to SCT in our next GRAAPH-2013 trial. The trend towards a better outcome after autologous compared to allogeneic SCT observed in MRD responders validates MRD as an important early surrogate endpoint for treatment stratification and new drug investigation in this disease.
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PURPOSE: To evaluate the cause of recurrent pathologic instability after anterior cruciate ligament (ACL) surgery and the effectiveness of revision reconstruction using a quadriceps tendon autograft using a 2-incision technique. TYPE OF STUDY: Retrospective follow-up study. METHODS: Between 1999 and 2001, 31 patients underwent ACL revision reconstruction because of recurrent pathologic instability during sports or daily activities. Twenty-eight patients were reviewed after a mean follow-up of 4.2 years (range, 3.3 to 5.6 years). The mean age at revision surgery was 27 years (range, 18 to 41 years). The average time from primary procedure to revision surgery was 26 months (range, 9 to 45 months). A clinical, functional, and radiographic evaluation was performed. Also magnetic resonance imaging (MRI) or computed tomography (CT) scanning was performed. The International Knee Documentation Committee (IKDC), Lysholm, and Tegner scales were used. A KT-1000 arthrometer measurement (MEDmetric, San Diego, CA) by an experienced physician was made. RESULTS: Of the failures, 79% had radiographic evidence of malposition of their tunnels. In only 6 cases (21%) was the radiologic anatomy of tunnel placement judged to be correct on both the femoral and tibial side. The MRI or CT showed, in 6 cases, a too-centrally placed femoral tunnel. After revision surgery, the position of tunnels was corrected. A significant improvement of Lachman and pivot-shift phenomenon was observed. In particular, 17 patients had a negative Lachman test, and 11 patients had a grade I Lachman with a firm end point. Preoperatively, the pivot-shift test was positive in all cases, and at last follow-up in 7 patients (25%) a grade 1+ was found. Postoperatively, KT-1000 testing showed a mean manual maximum translation of 8.6 mm (SD, 2.34) for the affected knee; 97% of patients had a maximum manual side-to-side translation <5 mm. At the final postoperative evaluation, 26 patients (93%) graded their knees as normal or nearly normal according to the IKDC score. The mean Lysholm score was 93.6 (SD, 8.77) and the mean Tegner activity score was 6.1 (SD, 1.37). No patient required further revision. Five patients (18%) complained of hypersensitive scars from the reconstructive surgery that made kneeling difficult. CONCLUSIONS: There were satisfactory results after ACL revision surgery using quadriceps tendon and a 2-incision technique at a minimum 3 years' follow-up; 93% of patients returned to sports activities. LEVEL OF EVIDENCE: Level IV, case series, no control group.
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Goals: Adjuvant chemotherapy decisions in breast cancer are increasing based on the pathologist's assessment of the proliferation fraction in the tumor. Yet, how good and how reproducible are we pathologists at providing reliable Ki-67 readings on breast carcinomas. Exactly how to count and in which areas to count within a tumor remains inadequately standardized. The Swiss Working Group of Gyneco- and Breast Pathologists has tried to appreciate this dilemma and to propose ways to obtain more reproducible results.Methods: In a first phase, 5 pathologists evaluated Ki67 counts in 10 breast cancers by exact counting (500 cells) and by eyeballing. Pathologists were free to select the region in which Ki67 was evaluated. In a second phase 16 pathologists evaluated Ki-67 counts in 3 breast cancers also by exact counting and eyeballing, but in predefined fields of interest. In both phases, Ki67 was assessed in centrally immunostained slides (ZH) and on slides immunostained in the 11 participating laboratories. In a third phase, these same 16 pathologists were once again asked to read the 3 cases from phase 2, plus three new cases, and this time exact guidelines were provided as to what exactly is considered a Ki-67 positive nucleus.Results: Discordance of Ki67 assessment was due to each of the following 4 factors: (i) pathologists' divergent definitions of what counts as a positive nucleus (ii) the mode of assessment (counting vs. eyeballing), (iii) immunostaining technique/protocol/antibody, and (iv) the selection of the area in which to count.Conclusion: Providing guidelines as to where to count (representative field in the tumor periphery and omitting hot spots) and what nuclei to count (even faintly immunostained nuclei count as positive) reduces the discordance rates of Ki67 readings between pathologists. Laboratory technique is only of minor importance (even over a large antibody dilution range), and counting nuclei does not improve accuracy, but rather aggravates deviations from the group mean values.Disclosure of Interest: None Declared
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Centrally located in America’s upper Midwest, Iowa lies in the heart of a 12-state region that will have installed an average of 2,701 mfi per year through 2014. In 2009 alone, this region, which is within one day delivery from Iowa, installed turbines valued at $7.8 billion! Once you understand how this exploding growth in the market intersects with the supply chain established by over 250 Iowa companies that are already providing components and services to wind energy manufacturers, you have an outstanding picture of exactly why all major wind manufacturing components are made in Iowa.
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BACKGROUND: Cilengitide is a selective αvβ3 and αvβ5 integrin inhibitor. Data from phase 2 trials suggest that it has antitumour activity as a single agent in recurrent glioblastoma and in combination with standard temozolomide chemoradiotherapy in newly diagnosed glioblastoma (particularly in tumours with methylated MGMT promoter). We aimed to assess cilengitide combined with temozolomide chemoradiotherapy in patients with newly diagnosed glioblastoma with methylated MGMT promoter. METHODS: In this multicentre, open-label, phase 3 study, we investigated the efficacy of cilengitide in patients from 146 study sites in 25 countries. Eligible patients (newly diagnosed, histologically proven supratentorial glioblastoma, methylated MGMT promoter, and age ≥18 years) were stratified for prognostic Radiation Therapy Oncology Group recursive partitioning analysis class and geographic region and centrally randomised in a 1:1 ratio with interactive voice response system to receive temozolomide chemoradiotherapy with cilengitide 2000 mg intravenously twice weekly (cilengitide group) or temozolomide chemoradiotherapy alone (control group). Patients and investigators were unmasked to treatment allocation. Maintenance temozolomide was given for up to six cycles, and cilengitide was given for up to 18 months or until disease progression or unacceptable toxic effects. The primary endpoint was overall survival. We analysed survival outcomes by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00689221. FINDINGS: Overall, 3471 patients were screened. Of these patients, 3060 had tumour MGMT status tested; 926 patients had a methylated MGMT promoter, and 545 were randomly assigned to the cilengitide (n=272) or control groups (n=273) between Oct 31, 2008, and May 12, 2011. Median overall survival was 26·3 months (95% CI 23·8-28·8) in the cilengitide group and 26·3 months (23·9-34·7) in the control group (hazard ratio 1·02, 95% CI 0·81-1·29, p=0·86). None of the predefined clinical subgroups showed a benefit from cilengitide. We noted no overall additional toxic effects with cilengitide treatment. The most commonly reported adverse events of grade 3 or worse in the safety population were lymphopenia (31 [12%] in the cilengitide group vs 26 [10%] in the control group), thrombocytopenia (28 [11%] vs 46 [18%]), neutropenia (19 [7%] vs 24 [9%]), leucopenia (18 [7%] vs 20 [8%]), and convulsion (14 [5%] vs 15 [6%]). INTERPRETATION: The addition of cilengitide to temozolomide chemoradiotherapy did not improve outcomes; cilengitide will not be further developed as an anticancer drug. Nevertheless, integrins remain a potential treatment target for glioblastoma. FUNDING: Merck KGaA, Darmstadt, Germany.
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Tolperisone (Mydocalm(®)) is a centrally acting muscle relaxant with few sedative side effects that is used for the treatment of chronic pain conditions. We describe three cases of suicidal tolperisone poisoning in three healthy young subjects in the years 2006, 2008 and 2009. In all cases, macroscopic and microscopic autopsy findings did not reveal the cause of death. Systematic toxicological analysis (STA) including immunological tests, screening for volatile substances and blood, urine and gastric content screening by GC-MS and HPLC-DAD demonstrated the presence of tolperisone in all cases. In addition to tolperisone, only the analgesics paracetamol (acetaminophen), ibuprofen and naproxen could be detected. The blood ethanol concentrations were all lower than 0.10g/kg. Tolperisone was extracted by liquid-liquid extraction using n-chlorobutane as the extraction solvent. The quantification was performed by GC-NPD analysis of blood, urine and gastric content. Tolperisone concentrations of 7.0mg/l, 14mg/l and 19mg/l were found in the blood of the deceased. In the absence of other autopsy findings, the deaths in these three cases were finally explained as a result of lethal tolperisone ingestion. To the best of our knowledge, these three cases are the first reported cases of suicidal tolperisone poisonings.
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The mechanisms sustaining high blood pressure in conscious one-kidney, one-clip Goldblatt rats were evaluated with the use of SK&F 64139, a phenylethanolamine N-methyltransferase inhibitor capable of crossing the blood-brain barrier and of captopril, an angiotensin converting enzyme inhibitor. The rats were studied 3 weeks after left renal artery clipping and contralateral nephrectomy. During the developmental phase of hypertension, two groups of rats were maintained on a regular salt (RNa) intake, whereas two other groups were given a low salt (LNa) diet. On the day of the experiment, the base-line mean blood pressure measured in the LNa rats (177.4 +/- 5.2 mm Hg, mean +/- S.E., n = 15) was similar to that measured in the RNa rats (178.7 +/- 5.4 mm Hg, n = 16). SK&F 64139 (12.5 mg p.o.) induced a significantly more pronounced (P less than .001) blood pressure decrease in the RNa rats (-25.6 +/- 3.6 mm Hg, n = 8) than in the LNa rats (-4.3 +/- 3.3 mm Hg, n = 7) during a 90-min observation period. On the other hand, captopril (10 mg p.o.) normalized blood pressure in LNa rats (n = 8), but produced only a 13.4 mm Hg blood pressure drop in RNa rats (n = 8). RNa rats treated with SK&F 64139 were found to have decreased phenylethanolamine N-methyltransferase activity by an average 80% in selected brain stem nuclei when compared with nontreated rats. No significant difference in plasma catecholamine levels was found between the RNa and LNa rats. These results suggest that, in this experimental model of hypertension, the sodium ion might increase the model of hypertension, the sodium ion might increase the vasoconstrictor contribution of the sympathetic system via a centrally mediated neurogenic mechanism while at the same time it decreases the renin-dependency of the high blood pressure.