Carotid artery repair for radiation-associated atherosclerosis is a safe and durable procedure

OBJECTIVE: The development of carotid atherosclerosis after neck irradiation is well documented. There has been concern about the safety and durability of carotid artery repair through a radiated field. The objective of this report is to describe the immediate and long-term results of a series of cases collected in a 13-year interval. METHODS: From 1984 to 1997, 24 patients underwent 26 carotid artery operations. All the patients had undergone prior radiation therapy at a mean interval of 17 years, with an average radiation dose of 6300 rad. Severe scarring of the skin or radiation fibrosis were present in two thirds of the patients, with 4 patients having permanent tracheostomies. The indications for carotid surgery included cerebral or monocular transient ischemic attack (58%), asymptomatic high-grade stenosis (27%), prior stroke (12%), and tumor invasion of the carotid artery (4%). General anesthesia was used with selective shunting on the basis of carotid artery back pressure or electroencephalography monitoring. Patch angioplasty closure was used in 79% of the patients. The operations included standard carotid endarterectomy (n = 20), external carotid endarterectomy (n = 2), carotid patch angioplasty alone (n = 2), aortocarotid bypass grafting (n = 1), and carotid interposition grafting (n = 1). Four patients required skin grafting or myocutaneous flaps. RESULTS: No deaths or strokes occurred within 30 days of the operations. Six patients had transient cranial nerve palsy, and two had wound infections. The patients were followed from 1 to 156 months, with six patients being followed for longer than 18 months. No strokes were seen at late follow-up examination. Duplex scan examination documented one occlusion, in a patient with primary closure, and two restenoses, one of which necessitated reoperation. The remainder of the grafts were widely patent. CONCLUSIONS: Carotid surgery after neck irradiation is safe and durable. The long-term patency rates and the protection against subsequent neurologic events are similar to the results obtained in the absence of radiation therapy. Problems of wound healing were not found in this series.     

Exercise training, postprandial hypertriglyceridemia, and LDL subfraction distribution

The purpose of this study was to examine differences in postprandial hypertriglyceridemia (PP-HTG) and low density lipoprotein (LDL) subfraction distribution among groups of men and women with different fitness levels. Fifty-four men and women (ages 30-53 yr) were recruited based on their previous two-year activity level: sedentary (S), recreational exercisers (R), and endurance trained (T). After a 24-h dietary preparation, blood was collected, and LDL subfractions were separated and analyzed for cholesterol (C) and apoprotein B100. Plasma triglyceride (TG) concentration was assessed before and at 2, 4, 6, and 8 h after fat meal. PP-HTG was significantly higher for the S group compared with the two activity groups. LDL3-C and LDL3-apoprotein B100 were significantly higher for the S group compared with the T group and for men compared with women. These findings suggest that both recreational and competitive aerobic training are associated with a lower TG response after a fatty meal. However, higher volume aerobic training may be necessary to reduce the number of dense LDL molecules and their cholesterol content.     

Mutant rescue by BAC clone injection in zebrafish

PURPOSE: To evaluate the rate of tumor recurrence within the irradiated volume after initial low-dose irradiation of limited-stage small-cell lung cancer (SCLC), to assess the tolerance of a sequential combination of low-dose chest irradiation followed by chemotherapy, and to confirm the responsiveness of limited-stage SCLC to low-dose irradiation. METHODS AND MATERIALS: In this pilot study, 26 patients with limited-stage SCLC were treated by first-line 20-Gy thoracic irradiation followed 3 weeks later by chemotherapy (cisplatin, doxorubicin, and etoposide for six cycles). RESULTS: We present our final results with a median follow-up of surviving patients of 7 years. The response rate to this low-dose irradiation was 83%, with an overall response rate to radiochemotherapy of 96% and a median survival of 21 months. No unexpected early or late toxicity was observed. The rate of initial isolated local failure was 8%, which compares favorably with other published series using higher doses of radiochemotherapy. CONCLUSION: An initial chest irradiation of 20 Gy before chemotherapy could be sufficient to reduce the risk of local failure during the time of survival of patients with limited-stage SCLC. Potential advantages of this treatment may be the prevention of resistance mechanisms to radiotherapy induced by preliminary chemotherapy and a reduced radiation-induced toxicity.     

Differences in muscle endurance and recovery between fallers and nonfallers, and between young and older women

BACKGROUND: Significant morbidity and mortality are associated with falls in older adults. We tested the hypothesis that older women with a history of falls demonstrate decreased muscle endurance and longer recovery times following fatiguing exercise. METHODS: We evaluated dynamic endurance and recoverability of the quadriceps femoris of 29 young women (YW) (M age = 21.7), 26 older women with a history of falls (FA) (M age = 73.3), and 27 older women with no history of falls (NF) (M age = 71.2) using an isokinetic dynamometer. Subjects performed repeated maximal concentric knee extensions until the force output of two consecutive repetitions fell below 50% of their maximal voluntary contraction (MVC). Recovery was defined as the time required for the return of force output > or = 80% MVC for 2 consecutive repetitions, within a set consisting of 3 maximal contractions. One minute rest was allowed between sets. We collected electromyographic (EMG) data from the quadriceps during all testing to evaluate spectral shifts. RESULTS: ANOVA with a post-hoc Bonferroni-Dunn test revealed time to fatigue was significantly faster in FA than YW (p < .02) and in FA than NF (p < .05), but not different between YW and NF. Time to recovery was significantly slower in FA than YW (p = .01), but not different between YW and NF, or between FA and NF, EMG median frequency power shift (from the beginning to the end of the test) was significantly less in FA (p < .001) than either YW (p < .002) or NF (p < .05). CONCLUSIONS: Older women with a history of falls demonstrate decreased muscular endurance compared to YW and NF, and increased time to recover from fatiguing exercise when compared to young women.     

The haematological management of patients with cyanotic congenital heart disease. A time for consensus?

AIMS: Recurrent venesection of patients with cyanotic congenital heart disease may be detrimental, with an increased risk of cerebrovascular events and symptomatic iron-deficiency. The aim of this study was to determine the venesection policies as practised in hospitals within a U.K. region and to determine if these policies followed current recommendations. METHODS AND RESULTS: Fifty-eight consultants (56% response rate) in cardiac specialties completed self-assessment questionnaires regarding the indications for and practice of venesection. Sixty-one percent of those responding were involved directly in the care of patients with cyanotic congenital heart disease and of these clinicians 97% used venesection. Indications for venesection varied, with 51% of those responding using an elevated haemoglobin per se (6.5-21.0 g. dl-1); 78% an elevated haematocrit (0.55-0.75) and 83% symptoms. Desired maintenance haemoglobin and haematocrit levels also varied greatly. Fifty percent of the consultants responding routinely screened their patients for iron deficiency and 23% felt there was no indication for investigating a low mean corpuscular volume. Only 18% of the policies described followed any evidence based principles. CONCLUSIONS: The practice of venesecting patients with congenital cyanotic heart disease varies greatly. Policies in many hospitals do not reflect the minimal benefits and considerable risks associated with recurrent venesection.     

Relationship between thermal stability, degradation rate and expression yield of barnase variants in the periplasm of Escherichia coli

An advantage of exporting a recombinant protein to the periplasm of Escherichia coli is decreased proteolysis in the periplasm compared with that in the cytoplasm. However, protein degradation in the periplasm also occurs. It has been widely accepted that the thermodynamic stability of a protein is an important factor for protein degradation in the cytoplasm of E.coli. To investigate the effect of the thermodynamic stability of an exported protein on the extent of proteolysis in the periplasm, barnase (an extracellular ribonuclease from Bacillus amyloliquefaciens) fused to alkaline phosphatase leader peptide was used as a model protein. A set of singly or doubly mutated barnase variants were constructed for export to the E.coli periplasm. It was found that the half-life of the barnase variants in vivo increased with their thermodynamic stability in vitro. A dominant factor for the final yield of exported barnase was not exportability but the turnover rate of the barnase variant. The yield of a stabilized mutant was up to 50% higher than that of the wild type. This suggests that exporting a protein to the periplasm and using protein engineering to enhance the stability can be combined as a strategy to optimize the production of recombinant proteins.     

Radiological features of focal nodular hyperplasia of the liver in children

BACKGROUND: Focal nodular hyperplasia (FNH) is an unusual hepatic tumour in children and should be distinguished from other hepatic lesions. OBJECTIVE: To describe the imaging characteristics of FNH in children. MATERIALS AND METHODS: We examined five patients (three boys and two girls, mean age 9.4 years) with pathologically confirmed FNH. The diagnosis was obtained by tumour resection (n = 4) and percutaneous needle biopsy (n = 1). One patient with multiple FNHs showed recurrent lesions after tumour resection. All patients were studied with US (including colour and power Doppler US [n = 3]) and CT. Dynamic enhanced CT scans were available in three patients. MRI (n = 2) or coeliac angiography (n = 1) was performed in three patients. RESULTS: Seven of eight FNH lesions in five patients were demonstrated by imaging. The average size of the lesions was 6.5 cm. Six lesions detected on US showed variable echogenicity with a central hyperechoic scar (n = 2). On Doppler examination, central or peripheral hypervascular areas were seen (n = 3). Six lesions detected on contrast-enhanced CT showed high attenuation (n = 4) or iso-attenuation (n = 2). On early phase scans, all the lesions (n = 3) showed high attenuation. Irregular linear or ovoid central scars were detected in two patients on CT. MR demonstrated three lesions in two patients, one of which had not been detected by US or CT. A central low signal intensity scar (n = 1) was seen on T2-weighted MRI. Coeliac angiography performed in one patient showed a hypervascular mass with homogeneous staining. CONCLUSION: FNH in children shows a wide spectrum of imaging findings on various radiological examinations and the typical central scar was not always seen on imaging studies. Dynamic enhanced CT obtained in the early phase and colour Doppler studies may be helpful in the diagnosis of FNH by allowing characterisation of tumour vascularity. FNH should be included in the differential diagnosis of liver mass in children.