The chemical heterogeneity of ethylene–propylene copolymers by multiple fractionation techniques is addressed. Three metallocene copolymer samples with different ethylene contents, ranging from 30 to 50 mol% are analyzed using bulk methods to confirm their molecular heterogeneity. In a second step, the samples are fractionated by temperature rising elution fractionation (TREF) to obtain fractions at 30, 60, 90, and 130 °C. These fractions are subsequently analyzed regarding their thermal and molecular properties. Differential scanning calorimetry, crystallization analysis fractionation, and high‐temperature high performance liquid chromatography (HT‐HPLC) results reveal that the TREF fractions collected at 130 °C are mainly due to polypropylene homopolymer, which is rather unexpected considering the high ethylene contents of the bulk samples. Most importantly, HT‐HPLC reveals a remarkably high chemical heterogeneity of the fractions and thus the bulk samples. Solution 13C NMR provides the comonomer contents and sequence distributions of the fractions. These indicate that the same TREF fractions from different samples have distinctively different chemical compositions.
Summary Febrile neutropenic events (FNE) were studied in 90 patients on chemotherapy protocols for solid tumours, from 1986 to 1990. All patients received intensive chemotherapy with a high dose intensity. There were 51 FNE admissions in 31 patients, with an average event rate of 1.6/patient. The average periods of granulocytopenia, fever and admission were 3.5, 2.7 and 5.4 days respectively. The management of FNE consisted of accurate clinical observation and antibiotic treatment if indicated by symptoms of infection or by bacteriological cultures. Only 25 of 51 patients admitted received empiric broad-spectrum antibiotics, while 7 were treated after the results of bacteriological cultures were known. One patient died during granulocytopenia, of interstitial pneumonitis for which no bacteriological source was established. Recurrences of infection after discharge from the hospital were not seen. We conclude that in this group of young adult patients, FNE runs a favourable course. Only a short period of admission and a limited form of antibiotic treatment are needed, minimizing the load on the patient and the costs of their care.Abbreviation FNE
febrile neutropenic events 相似文献
Oral methadone may be prescribed to detainees with the aim of minimising the risk of fatal opioid poisoning on release. To study the circumstances under which methadone-related deaths can occur in detention, we audited reports of 17 [14 male, 3 female; median (range) age 34 (22–52) years] such deaths, July 2010–December 2011. The median (range) methadone dose was 40 (10–110) mg/d (N = 16). The median (range) post-mortem blood methadone concentration was 0.42 (0.16–1.40) mg/L. Those who died within 7 days of the commencement of methadone treatment were significantly younger (Mann-Whitney U 102.5, p < 0.05), were prescribed a significantly lower dose (U = 80.0, p < 0.05) and had significantly lower blood methadone concentrations at death (U = 106.5, p < 0.02) than in those given methadone long-term. In 8 reports the prisoner had been recorded as either ‘sleepy’ (N = 7), or ‘unwell’ in the hours before death. In 13 deaths, the prisoner was either found dead first thing in the morning, or in one instance could not be roused (‘snoring heavily’). Pneumonia, tracheobronchitis, end-stage cirrhosis, and ischaemic heart disease/coronary artery atherosclerosis were cited as associated factors in four patients, all of whom were on long term stable methadone treatment. Attention to warning signs of likely methadone toxicity (daytime or excessive drowsiness, snoring, nausea/vomiting) and associated risk factors (use of drugs such as benzodiazepines and gabapentinoids, the presence of respiratory infection, liver or renal disease) could help minimise the risk of unexpected death in patients given methadone. 相似文献
Quantitative trait loci (QTL) mapping of complex phenotypes has emerged as an important feature of the recombinant inbred (Rl) strain methodology. In this second study of our series on alcohol-related behaviors in mice, we examine alcohol acceptance, preference, and hypnotic dose sensitivity (HDS) to a standard dose of alcohol measured in BXD RI strains to identify candidate QTL regions responsible for their heritability. We detected highly significant marker associations for acceptance on chromosome 12 (Eif4e) , for preference on chromosome 1 (D1Rti2) and chromosome 7 (D7Mit7) , and for HDS on chromosome 7 (Mpmv1). These are the strongest QTL associations that we detected, but several other candidate QTL regions are reported. Given the limited number of BXD RI strains available, the large number of markers used herein, and the consequent chance of identifying false marker associations, these RI QTL mapping results must be seen as tentative, but an important first step toward identifying QTL for alcohol-related behaviors. 相似文献
BackgroundThe recommended external beam radiotherapy (EBRT) dose for cervical cancer is 40–50 Gy, but there is no consensus. In this study, 45-Gy and 50.4-Gy treatment groups were compared for fused doses to target tumor areas and organs at risk (OARs), clinical efficacy, and quality of life.MethodsSeventy-nine cases receiving radical radiotherapy within the past 3 years were retrospectively analyzed. EBRT and three-dimensional brachytherapy dose fusion values were calculated for target areas and OARs using Elastix V5.0. Clinical efficacy was assessed using Response Evaluation Criteria in Solid Tumors (RECIST), adverse events using Common Terminology Criteria for Adverse Events v4.03 (CTCAE4.03), and quality of life using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30).ResultsMinimum fused dose delivered to 90% of the high-risk clinical target volume (HRCTV D90) did not differ significantly between 45-Gy and 50.4-Gy groups, whereas D2cc values of rectum and bladder (OARs) were significantly lower in the 45-Gy group (both p < 0.05). Further analysis showed that these D2cc differences resulted primarily from EBRT. No grade III–IV adverse events were observed in either group during follow up. Short-term clinical efficacy, adverse events, and EORTC QLQ-C30 functional and symptom scales also did not differ significantly between groups (all p > 0.05). However, quality of life was markedly higher in the 45-Gy group (p < 0.05).ConclusionAppropriate EBRT dose reduction can reduce OAR irradiation without compromising total target area dose or clinical efficacy. Dose fusion can facilitate the judicious choice of EBRT to limit OAR exposure, reduce adverse events, and enhance the quality of life. 相似文献
BackgroundCardiac computed tomography (CT) is increasingly used in pediatric patients with congenital heart disease (CHD). Variability of practice and of comprehensive diagnostic risk across institutions is not known.MethodsFour centers prospectively enrolled consecutive pediatric CHD patients <18 years of age undergoing cardiac CT from January 6, 2017 to 1/30/2020. Patient characteristics, cardiac CT data and comprehensive diagnostic risk were compared by age and institutions. Risk categories included sedation and anesthesia use, vascular access, contrast exposure, cardiovascular medication, adverse events (AEs), and estimated radiation dose.ResultsCardiac CT was performed in 1045 pediatric patients at a median (interquartile range, IQR) age of 1.7 years (0.3, 11.0). The most common indications were arterial abnormalities, suspected coronary artery anomalies, functionally single ventricle heart disease, and tetralogy of Fallot/pulmonary atresia. Sedation was used in 8% and anesthesia in 11% of patients. Peripheral vascular access was utilized for 93%. Median contrast volume was 2 ml/kg. Beta blockers were administered in 11% of cases and nitroglycerin in 2% of cases. The median (IQR) total procedural dose length product (DLP) was 20 mGy1cm (10, 50). Sedation, vascular access, contrast exposure, use of cardiovascular medications and radiation dose estimates varied significantly by institution and age (p < 0.001). Seven minor adverse events (0.7%) and no major adverse events were reported.ConclusionCardiac CT for CHD is safe in pediatric patients when appropriate CT technology and expertise are available. Scans can be acquired at relatively low radiation exposure with few minor adverse events. 相似文献
AIM: To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography(MDCT) in suspected scaphoid fractures.METHODS: One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities.RESULTS: Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients(42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT(P < 0.01) concerning scaphoidfracture detection. The mean effective dose of MDCT was 0.1 m Sv compared to 0.002 m Sv of conventional radiography.CONCLUSION: Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma. 相似文献
Granulocyte‐monocyte apheresis (GMA) is an emerging therapeutic option in active course of ulcerative colitis (UC). Appropriate GMA dose, including total number, frequency, and duration of the individual GMA session, is a matter of debate. It was the aim of the present study to evaluate the efficacy of a dose‐intensified GMA regimen in patients with moderately to severely active UC. A prospective open‐label, single‐center study was performed in 10 patients with active UC (Rachmilewitz Clinical Activity Index [CAI] ≥ 8 points; Rachmilewitz Endoscopic Index ≥ 7 points). Patients had failed to improve after treatment with steroids and/or immunomodulators. GMA was performed twice weekly for 2 h to a maximum of 10 sessions. In each GMA session, the adsorber was changed after 1 h of treatment time. Four patients achieved remission with a CAI ≤ 4 points. Three patients had a response with an improvement of CAI of ≥3 points. Three patients showed no benefit from GMA. The quality of life score determined by the inflammatory bowel disease questionnaire‐Deutschland increased by 26 points in median. First and second filters had similar efficiency in granulocyte and monocyte adsorption. No major adverse effects were observed. Dose‐intensified GMA as reported in this study provided an encouraging short‐term response rate of 70% in patients with moderately to severely active UC not responding to standard steroid or immunomodulator therapy. Although all patients relapsed not later than 16 weeks, GMA might be useful to reduce steroid and immunomodulator usage, or to delay surgery in this patient group. 相似文献
下载免费PDF全文