Dietary habits and esophageal cancer.

Cancer of the esophagus is an underestimated, poorly understood, and changing disease. Its overall 5-year survival is less than 20%, even in the United States, which is largely a function of a delay in diagnosis until its more advanced stages. Additionally, the epidemiologic complexities of esophageal cancer are vast, rendering screening and prevention limited at best. First, the prevalence of esophageal cancer is unevenly distributed throughout the world. Second, the two histological forms (squamous cell and adenocarcinoma) vary in terms of their geographic prevalence and associated risk factors. Third, some populations appear at particular risk for esophageal cancer. And fourth, the incidence of esophageal cancer is in continuous flux among groups. Despite the varied prevalence and risks among populations, some factors have emerged as consistent associations while others are only now becoming more fully recognized. The most prominent, scientifically supported, and long-regarded risk factors for esophageal cancer are tobacco, alcohol, and reflux esophagitis. Inasmuch as the above are regarded as important risk factors for esophageal cancer, they are not the sole contributors. Dietary habits, nutrition, local customs, and the environment may be contributory. Along these lines, vitamins, minerals, fruits, vegetables, meats, fats, salted foods, nitrogen compounds, carcinogens, mycotoxins, and even the temperature of what we consume are increasingly regarded as potential etiologies for this deadly although potentially preventable disease. The goal of this review is to shed light on the less known role of nutrition and dietary habits in esophageal cancer.

Estimating genome-wide heterozygosity: effects of demographic history and marker type.

Heterozygosity-fitness correlations (HFCs) are often used to link individual genetic variation to differences in fitness. However, most studies examining HFCs find weak or no correlations. Here, we derive broad theoretical predictions about how many loci are needed to adequately measure genomic heterozygosity assuming different levels of identity disequilibrium (ID), a proxy for inbreeding. We then evaluate the expected ability to detect HFCs using an empirical data set of 200 microsatellites and 412 single nucleotide polymorphisms (SNPs) genotyped in two populations of bighorn sheep (Ovis canadensis), with different demographic histories. In both populations, heterozygosity was significantly correlated across marker types, although the strength of the correlation was weaker in a native population compared with one founded via translocation and later supplemented with additional individuals. Despite being bi-allelic, SNPs had similar correlations to genome-wide heterozygosity as microsatellites in both populations. For both marker types, this association became stronger and less variable as more markers were considered. Both populations had significant levels of ID; however, estimates were an order of magnitude lower in the native population. As with heterozygosity, SNPs performed similarly to microsatellites, and precision and accuracy of the estimates of ID increased as more loci were considered. Although dependent on the demographic history of the population considered, these results illustrate that genome-wide heterozygosity, and therefore HFCs, are best measured by a large number of markers, a feat now more realistically accomplished with SNPs than microsatellites.

Deletion of Sod1 in Motor Neurons Exacerbates Age-Related Changes in Axons and Neuromuscular Junctions in Mice.

Whole-body knock-out of Cu,Zn superoxide dismutase (Sod1KO) results in accelerated, age-related loss of muscle mass and function associated with neuromuscular junction (NMJ) breakdown similar to sarcopenia. In order to determine whether altered redox in motor neurons underlies this phenotype, an inducible neuron-specific deletion of Sod1 (i-mnSod1KO) was compared with wild-type (WT) mice of different ages (adult, mid-age, and old) and whole-body Sod1KO mice. Nerve oxidative damage, motor neuron numbers and structural changes to neurons and NMJ were examined. Tamoxifen-induced deletion of neuronal Sod1 from two months of age. No specific effect of a lack of neuronal Sod1 was seen on markers of nerve oxidation (electron paramagnetic resonance of an in vivo spin probe, protein carbonyl, or protein 3-nitrotyrosine contents). i-mnSod1KO mice showed increased denervated NMJ, reduced numbers of large axons and increased number of small axons compared with old WT mice. A large proportion of the innervated NMJs in old i-mnSod1KO mice displayed a simpler structure than that seen in adult or old WT mice. Thus, previous work showed that neuronal deletion of Sod1 induced exaggerated loss of muscle in old mice, and we report that this deletion leads to a specific nerve phenotype including reduced axonal area, increased proportion of denervated NMJ, and reduced acetyl choline receptor complexity. Other changes in nerve and NMJ structure seen in the old i-mnSod1KO mice reflect aging of the mice.

QTL mapping for sexually dimorphic fitness-related traits in wild bighorn sheep.

Dissecting the genetic architecture of fitness-related traits in wild populations is key to understanding evolution and the mechanisms maintaining adaptive genetic variation. We took advantage of a recently developed genetic linkage map and phenotypic information from wild pedigreed individuals from Ram Mountain, Alberta, Canada, to study the genetic architecture of ecologically important traits (horn volume, length, base circumference and body mass) in bighorn sheep. In addition to estimating sex-specific and cross-sex quantitative genetic parameters, we tested for the presence of quantitative trait loci (QTLs), colocalization of QTLs between bighorn sheep and domestic sheep, and sex × QTL interactions. All traits showed significant additive genetic variance and genetic correlations tended to be positive. Linkage analysis based on 241 microsatellite loci typed in 310 pedigreed animals resulted in no significant and five suggestive QTLs (four for horn dimension on chromosomes 1, 18 and 23, and one for body mass on chromosome 26) using genome-wide significance thresholds (Logarithm of odds (LOD) >3.31 and >1.88, respectively). We also confirmed the presence of a horn dimension QTL in bighorn sheep at the only position known to contain a similar QTL in domestic sheep (on chromosome 10 near the horns locus; nominal P<0.01) and highlighted a number of regions potentially containing weight-related QTLs in both species. As expected for sexually dimorphic traits involved in male-male combat, loci with sex-specific effects were detected. This study lays the foundation for future work on adaptive genetic variation and the evolutionary dynamics of sexually dimorphic traits in bighorn sheep.

Hiatal hernias: a review of the pathophysiologic theories and implication for research.

BACKGROUND: The pathophysiology of hiatal hernias is incompletely understood. This study systematically reviewed the literature of hiatal hernias to provide an evidence-based explanation of the pathogenetic theories and to identify any risk factors at the molecular and cellular levels. METHODS: A systematic search of the Medline and Pubmed databases on the pathophysiology of hiatal hernias was performed to identify English-language citations from the database inception to December 2010. RESULTS: Although few studies have examined the relationship of molecular and cellular changes of the diaphragm to the pathogenesis of hiatal hernias, there appear to be three dominant pathogenic theories: (1) increased intraabdominal pressure forces the gastroesophageal junction (GEJ) into the thorax; (2) esophageal shortening due to fibrosis or excessive vagal nerve stimulation displaces the GEJ into the thorax; and (3) GEJ migrates into the chest secondary to a widening of the diaphragmatic hiatus in response to congenital or acquired molecular and cellular changes, such as the abnormalities of collagen type 3 alpha 1. CONCLUSIONS: The pathogenesis of hiatal hernias at the molecular and cellular levels is poorly described. To date, no single theory has proved to be the definitive explanation for hiatal hernia formation, and its pathogenesis appears to be multifactorial.

A review of the potential applications and controversies of non-invasive testing for biomarkers of aspiration in the lung transplant population.

Despite improvements in one-yr survival following lung transplantation, five-yr survival lags significantly behind the transplantation of other solid organs. The contrast in survival persists despite advancements in anti-rejection regimens, suggesting a non-alloimmune mechanism to chronic lung transplant failure. Notably, markers of aspiration have been demonstrated in bronchoalveolar lavage (BAL) fluid concurrent with bronchiolitis obliterans syndrome (BOS). This recent evidence has underscored gastroesophageal reflux (GER) and its associated aspiration risk as a non-alloimmune mechanism of chronic lung transplant failure. Given the suggested safety and efficacy of laparoscopic anti-reflux procedures in the lung transplant population, identifying those at risk for aspiration is of prime importance, especially concerning the potential for long-term improvements in morbidity and mortality. Conventional diagnostic methods for GER and aspiration, such as pH monitoring and detecting pepsin and bile salts in BAL fluid, have gaps in their effectiveness. Therefore, we review the applications and controversies of a non-invasive method of defining reflux injury in the lung transplant population: the detection of biomarkers of aspiration in the exhaled breath condensate. Only by means of assay standardization and directed collaboration may such a non-invasive method be a realization in lung transplantation.

The evolution and long-term results of laparoscopic antireflux surgery for the treatment of gastroesophageal reflux disease.

BACKGROUND: For nearly 2 decades, the laparoscopic correction of gastroesophageal reflux disease (GERD) has demonstrated its utility. However, the surgical technique has evolved over time, with mixed long-term results. We briefly review the evolution of antireflux surgery for the treatment of GERD, provide an update specific to the long-term efficacy of laparoscopic antireflux surgery (LARS), and analyze the factors predictive of a desirable outcome. MATERIALS AND METHODS: PubMed and Medline database searches were performed to identify articles regarding the laparoscopic treatment of GERD. Emphasis was placed on randomized control trials (RCTs) and reports with follow-up >1 year. Specific parameters addressed included operative technique, resolution of symptoms, complications, quality of life, division of short gastric vessels (SGVs), mesh repair, and approximation of the crura. Those studies specifically addressing follow-up of <1 year, the pediatric or elderly population, redo fundoplication, and repair of paraesophageal hernia and short esophagus were excluded. RESULTS: LARS has varied in technical approach through the years. Not until recently have more long-term, objective studies become available to allow for evidenced-based appraisals. Our review of the literature found no long-term difference in the rates of heartburn, gas-bloat, antacid use, or patient satisfaction between laparoscopic Nissen and Toupet fundoplication. In addition, several studies have shown that more patients had an abnormal pH profile following laparoscopic partial as opposed to total fundoplication. Conversely, dysphagia was more common following laparoscopic total versus partial fundoplication in 50% of RCTs at 12-month follow-up, though this resolved over time, being present in only 20% with follow-up >24 months. We confirmed that preoperative factors, such as hiatal hernia, atypical symptoms, poor antacid response, body mass index (BMI), and postoperative vomiting, are potential predictors of an unsatisfactory long-term outcome. Last, no trial disfavored division of the short gastric vessels (SGVs), closure of the crura, or mesh repair for hiatal defects. CONCLUSION: LARS has significantly evolved over time. The laparoscopic total fundoplication appears to provide more durable long-term results than the partial approach, as long as the technical elements of the operation are respected. Division of the SGVs, closure of the crura, and the use of mesh for large hiatal defects positively impacts long-term outcome. Hiatal hernia, atypical symptoms, poor antacid response, body mass index (BMI), and postoperative vomiting are potential predictors of failure in LARS.

Microaggregations of oceanic plankton observed by towed video microscopy.

Oceanic plankton have been hypothesized to occur in micropatches (<10 meters) that can have a large impact on marine ecosystem dynamics. Towed video microscopy was used to unobtrusively determine distributions of oceanic plankton over a continuum of scales from microns to hundreds of meters. Distinct, taxa-specific aggregations measuring less than 20 centimeters were found for copepods but not for nonmotile (cyanobacterial colonies) or asexual (doliolid phorozooids) forms, which suggests that these small patches are related to mating. Significant patchiness was also found on larger scales and was correlated among taxa, indicating physical control. These video observations provide new insights into basic plankton ecology by allowing quantitative assessment of individual plankton in their natural, undisturbed state.

Comparison of bacterial 16S rRNA variable regions for microbiome surveys of ticks.

Ticks vector diverse pathogenic bacteria that are important to identify in public health and veterinary contexts. Technological advances in high throughput sequencing have given an unprecedented opportunity to comprehensively characterize bacterial associates of ticks, but recent studies have used different 16S rRNA variable regions and sequence read lengths with little consideration of whether they reveal the same bacterial diversity. We compare the effectiveness of bacterial surveys using three library preparations across nine 16S variable regions and a set of 12 tick specimens (Acari: Ixodidae). We identify the bacterial assemblages present in extractions from wild-collected Ixodes scapularis from two regions of Canada, and provide the first microbiome survey for Ixodes angustus. Four bacterial families accounted for most diversity, with Rickettsiaceae being replaced as most common by Enterobacteriaceae or Pseudomonadaceae in some I. scapularis, and Francisellaceae being most abundant in I. angustus. The commercially available Ion 16S kit, based on 6 amplicons representing 16S regions V2, V3, V4, V67, V8 and V9, gave the most comprehensive estimates of bacterial families, with the Ion V4 amplicon generally giving the highest estimated diversity. Sequencing of the V4 amplicon by the MR DNA commercial service also provided cost effective assays of tick microbiomes that were within the range of results from the Ion 16S kit. Subtraction of the number of reads found in an extraction control sample lowered estimates of the number of bacterial families by approximately half. Our study shows that diversity patterns obtained from 16S microbiome surveys depend on the amplicon and protocol used, demonstrating that more than one marker region is needed to provide reliable inferences.

Intermittent energy restriction and weight loss: a systematic review.

BACKGROUND/OBJECTIVES: Intermittent energy restriction (IER) is an eating pattern of regular daily periods of restricted energy intake followed by periods of unrestricted energy intake. This is gaining prominence as an alternative weight-loss strategy to daily energy restriction (DER). The aim of this systematic review was to determine the effectiveness of IER on weight loss in overweight and obese adults and compare this with DER. SUBJECTS/METHODS: A systematic literature search was conducted using the CINAHL, Embase, Medline, PsycINFO, Cochrane and Scopus databases. Eight studies that assigned overweight or obese adults to IER or to a DER 'control' were deemed eligible for inclusion. RESULTS: All studies reported significant weight loss for IER groups. Average weight loss was approximately 0.2-0.8 kg per week. IER resulted in comparable weight loss to DER when overall energy restriction remained similar between diets. The majority of studies that reported body composition outcomes have shown equal efficacy for fat mass, fat-free mass and waist circumference. CONCLUSIONS: Weight loss was achieved in overweight and obese adults following IER and this loss was comparable to a DER diet. IER may be an effective alternative strategy for health practitioners to promote weight loss for selected overweight and obese people.

The measurement of phosphatidate phosphohydrolase in human amniotic fluid.

Phosphatidate phosphohydrolase (EC 3.1.3.4) activity can be found in late gestational human amniotic fluid and is thought to originate in type II alveolar cells of the fetal lungs where it plays an important role in lung surfactant synthesis. In the present study, phosphatidate phosphohydrolase activity was detected and characterized in a 105 000 X g pellet of amniotic fluid using either [32P]phosphatidate or a water-soluble analog, 1-O-hexadecyl-rac-[2-(3)H]glycerol 3-phosphate as substrate. With either substrate, enzyme activity was optimal at pH 6.0. The soluble analog was hydrolyzed with a Km value of 163 micrometer and a V of 30 nmole/min per mg of protein, and offered several advantages over phosphatidate as a substrate for assaying phosphatidate phosphohydrolase in amniotic fluid. Using the synthetic analog, phosphatidate phosphohydrolase activity was measured in the 700 X g supernatant fraction of 30 human amniocentesis samples and compared with another index of fetal lung maturity, the phosphatidylcholine/sphingomyelin ratio. The results suggest that the new phosphohydrolase assay may be clinically useful in the assessment of fetal lung development.

Randomized study of prophylactic platelet transfusion threshold during induction therapy for adult acute leukemia: 10,000/microL versus 20,000/microL.

PURPOSE: We designed and conducted a randomized single-institution trial comparing two common prophylactic platelet transfusion thresholds in patients undergoing induction therapy for acute leukemia. PATIENTS AND METHODS: Seventy-eight patients undergoing induction therapy for acute leukemia were randomized to receive prophylactic apheresis platelet concentrates when the platelet count was either < or = 10,000/microL or < or = 20,000/microL. RESULTS: There was no significant difference in the total number of bleeding episodes per patient with a median of four in the < or = 10,000/microL arm and two in the < or = 20,000/microL arm (25th to 75th percentiles of 2, 7 and 1, 5, respectively; P = .12). Patients randomized to the < or = 10,000/microL arm received more platelet transfusions for bleeding [one (0, 2) v zero (0, 0); P = .0003]. In contrast, patients on the < or = 20,000/microL arm received more platelet transfusions for prophylactic indications [10 (5, 14) v six (3, 8); P = 0.001], as would be expected, but less for bleeding. Nevertheless, the total number of platelet transfusions given to patients on the < or = 20,000/microL arm was higher and nearly significant [11 (6, 15) v seven (5, 11); P = .07]. There were no statistically significant differences between the groups with regard to RBC transfusion requirements, febrile days, days hospitalized, days thrombocytopenic, need for HLA-matched platelets, remission rate, or death during induction chemotherapy. No patient in either group died from hemorrhage or underwent major surgery for bleeding complications. CONCLUSION: Giving prophylactic platelets at a threshold of < or = 10,000/microL compared with < or = 20,000/microL can decrease the total utilization of platelets with only a small adverse effect on bleeding, and no statistically significant effect on morbidity.

A model of lifetime osteoporosis impact.

The study goal was to use population-based data to model aspects of lifetime osteoporosis impact not previously studied, specifically: (1) to estimate person-years of fracture-related functional impairment against the trajectory of functional status in the general population; (2) jointly to consider hip, vertebral, and Colles' fractures in estimating the percent of women who will ever fracture; and (3) to estimate the lifetime number of fractures expected in a cohort of 10,000 50-year-old white postmenopausal women. The model estimates that 54% of 50-year-old women will sustain osteoporosis-related fractures during their remaining lifetimes. Beyond the functional impairment expected in similarly aged, unfractured women, osteoporosis-related fractures are estimated to cause 6.7% of women to become dependent in basic activities of daily living; 7.8% are expected to require nursing home care for an average of 7.6 years.

A phase III study of belagenpumatucel-L, an allogeneic tumour cell vaccine, as maintenance therapy for non-small cell lung cancer.

BACKGROUND: Treatment options after first-line chemotherapy are limited in non-small cell lung cancer (NSCLC). Belagenpumatucel-L is a therapeutic vaccine comprised of 4 transforming growth factor (TGF)-ß2-antisense gene-modified, irradiated, allogeneic NSCLC cell lines that may be useful for maintenance after initial treatment. METHODS: Stage III/IV NSCLC patients who did not progress after platinum-based chemotherapy were randomised 1:1 to receive maintenance belagenpumatucel-L or placebo. Patients were eligible for randomisation between one and four months from the end of induction chemotherapy. The primary endpoint was overall survival. RESULTS: This phase III trial enrolled 270 patients in the belagenpumatucel-L arm and 262 in the control arm. Belagenpumatucel-L was well tolerated with no serious safety concerns. There was no difference in survival between the arms (median survival 20.3 versus 17.8months with belagenpumatucel-L versus placebo, respectively; hazard ratio (HR) 0.94, p=0.594). There were also no differences in progression-free survival (4.3months versus 4.0 for belagenpumatucel-L vs placebo, respectively; HR 0.99, p=0.947). A prespecified Cox regression analysis demonstrated that the time elapsed between randomisation and the end of induction chemotherapy had a significant impact on survival (p=0.002) and that prior radiation was a positive prognostic factor (median survival 28.4months with belagenpumatucel-L versus 16.0months with placebo; HR 0.61, p=0.032). CONCLUSIONS: Although the overall trial did not meet its survival endpoint, improved survival for belagenpumatucel-L is suggested in patients who were randomised within 12weeks of completion of chemotherapy and in those who had received prior radiation. Further studies of belagenpumatucel-L in NSCLC are warranted.

Kinetics of esmolol, an ultra-short-acting beta blocker, and of its major metabolite.

Esmolol is an ultra-short-acting beta blocker. Its kinetics was studied in eight healthy subjects after continuous intravenous infusion of 400 micrograms/kg/min over 2 hr. The concentrations of esmolol and its major metabolite, 3-[4-(2-hydroxy-3-[isopropylamino]propoxy)phenyl]propionic acid, in blood and urine were determined by gas chromatographic-mass spectrometric assay and HPLC. The distribution and elimination t1/2s of esmolol averaged 2.03 and 9.19 min. The apparent volume of distribution of esmolol averaged 3.43 l/kg and was four times the volume of the central compartment. The total clearance of esmolol averaged 285 ml/min/kg, indicating that nonhepatic routes play a predominant role in its clearance. The t1/2s of formation and elimination of the metabolite averaged 2.82 min and 3.72 hr. The ratio of the metabolite formation and elimination rate constants of the parent drug (kf/k10) averaged 0.829, suggesting that 82.9% of esmolol was converted to the metabolite (which is consistent with the urinary recovery of 71% of the dose as unconjugated metabolite). The volume of distribution and total clearance of the metabolite averaged 0.411 l/kg and 1.28 ml/min/kg. Esmolol was followed by a significant reduction of isoproterenol-induced increase in heart rate and systolic blood pressure at doses of 50, 150, and 400 micrograms/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)

The Clinician Interview-Based Impression (CIBI): a clinician's global change rating scale in Alzheimer's disease.

Global assessments are Food and Drug Administration-required primary outcome measures in trials of putative antidementia drugs. Global ratings are intended to provide an index of clinical importance of change that cannot be obtained from quantitative assessment measures such as mental status examinations. We examined the performance of a global assessment of change instrument, the Clinician Interview-Based Impression (CIBI), in the placebo group of a 30-week, randomized, double-blind clinical trial of tacrine in patients with Alzheimer's disease. Initially there were 184 placebo patients, of whom 125 completed the 30-week study. Descriptive statistics, correlations with changes on other assessment instruments, and test-retest reliability were determined for the CIBI. At week 30, clinicians rated more than 40% of patients on the CIBI as unchanged. The CIBI ratings were weakly but significantly correlated, in the expected direction, with change scores on the quantitative cognitive assessments. The CIBI was modestly reliable on test-retest at weeks 22 and 24 but less reliable compared with other quantitative outcome measures. Modifications of the CIBI that might improve its reliability and acceptance include (1) no restrictions on the form of the bedside mental status assessment, (2) inclusion of caregiver input, and (3) better definition of ratings on the global scale. Global instruments, if properly constructed, can provide an index of clinically important change for the assessment of dementia patients.

Effect of antipsychotic withdrawal on extrapyramidal symptoms: statistical methods for analyzing single-sample repeated-measures data.

Using symptom severity ratings of extrapyramidal side effects (EPS) during a 4-week antipsychotic washout period, we illustrate particular problems associated with repeated measures of symptom severity and demonstrate four analysis methods. The often suggested analysis of variance and multivariate analysis of variance found no mean change in weekly Simpson Angus scores over the 4-week washout despite the fact that 43% had clinically significant EPS prior to drug discontinuation. On the other hand, the Friedman Analysis of Ranks and Cochran-Mantel-Haenszel (CMH) statistics found significant change over the washout period. These two less well-known techniques place fewer restrictions on the data, can be more sensitive to patterns of change, and may be more appropriate for psychiatric data. The CMH method is particularly attractive since it does not require complete data on all subjects as do many other techniques. This minimizes the number of cases lost to missing data and increases the generality of the results.

Usefulness of tumor volumetry by magnetic resonance imaging in assessing response to radiation therapy in carcinoma of the uterine cervix.

PURPOSE: Clinical evaluation of tumor size in cervical cancer is often difficult, and clinical signs of radiation therapy failure may not be present until well after completion of treatment. The purpose of this study is to investigate early indicators of treatment response using magnetic resonance (MR) imaging for quantitative assessment of tumor volume and tumor regression rate before, during, and after radiation therapy. METHODS AND MATERIALS: Thirty-four patients with cervical cancer Stages IB [5], IIB [8], IIIA [1], IIIB [14], IVA [3], IVB [1], and recurrent [2] were studied prospectively with four serial MR examinations obtained at the start of radiation therapy, at 2-2.5 weeks (20-24 Gy), at 4-5 weeks (40-50 Gy), and 1-2 months after treatment completion. Tumor volume was assessed by three-dimensional volumetric measurements using T2-weighted images of each MR examination. The volume regression rate was generated based on the four sequential MR studies. These findings were correlated with local control, metastasis rate, and disease-free survival. Median follow-up was 18 months (range: 9-43 months). RESULTS: The tumor regression rate after a dose of 40-50 Gy correlated significantly with treatment outcome. The actuarial 2-year disease-free survival was 88.4% in patients with tumors regressing to < 20% of the initial volume compared with 45.4% in those with > or = 20% residual (p = 0.007). The incidence of local recurrence was 9.5% (2 out of 21) and 76.9% (10 out of 13), respectively (p < 0.001). Analysis by initial tumor volume showed that this observation was valid in patients with initial volumes between 40 and 100 cm3. Analysis by FIGO stage confirmed this observation in all patients except those with Stage IB. CONCLUSION: Sequential tumor volumetry using MR imaging appears to be a sensitive measure of the responsiveness of cervical cancer to irradiation. Treatment response can be assessed as early as during the course of radiation therapy by measurement of initial tumor volume and regression rate at 40-50 Gy. In patients with large (> 40 cm3) and advanced (Stage > or = IIIA) tumors, this technique may be helpful in supplementing the clinical examination for response assessment. The identification of patients at high risk for treatment failure may ultimately lead to improved clinical outcome.

Tumor perfusion studies using fast magnetic resonance imaging technique in advanced cervical cancer: a new noninvasive predictive assay.

PURPOSE: This study investigated sequential changes in tumor blood supply using magnetic resonance (MR) perfusion imaging and assessed their significance in the prediction of outcome of patients with advanced cervical cancer. The purpose of this project was to devise a simple, noninvasive method to predict early signs of treatment failure in advanced cervical cancer treated with conventional radiation therapy. METHODS AND MATERIALS: Sixty-eight MR perfusion studies were performed prospectively in 17 patients with squamous carcinomas (14) and adenocarcinomas (3) of the cervix, Stages bulky IB (1), IIB (5), IIIA (1), IIIB (8), and IVA (1), and recurrent (1). Four sequential studies were obtained in each patient: immediately before radiation therapy (pretherapy), after a dose of 20-22 Gy/ approximately 2 weeks (early therapy), after a dose of 40-45 Gy/ approximately 4-5 weeks (midtherapy), and 4-6 weeks after completion of therapy (follow-up). Perfusion imaging of the tumor was obtained at 3-s intervals in the sagittal plane. A bolus of 0.1 mmol/kg of MR contrast material (gadoteridol) was injected intravenously 30 s after beginning image acquisition at a rate of 9 ml/s using a power injector. Time/signal-intensity curves to reflect the onset, slope, and relative signal intensity (rSI) of contrast enhancement in the tumor region were generated. Median follow-up was 8 months (range 3-18 months). RESULTS: Tumors with a higher tissue perfusion (rSI > or = 2.8) in the pretherapy and early therapy (20-22 Gy) studies had a lower incidence of local recurrence than those with a rSI of < 2.8, but this was not statistically significant (13% vs. 67%; p = 0.05). An increase in tumor perfusion early during therapy (20-22 Gy), particularly to an rSI of > or = 2.8, was the strongest predictor of local recurrence (0% vs. 78%; p = 0.002). However, pelvic examination during early therapy (20-22 Gy) commonly showed no appreciable tumor regression. The slope of the time/signal-intensity curve obtained before and during radiation therapy also correlated with local recurrence. Follow-up perfusion studies did not provide information to predict recurrence. CONCLUSION: These preliminary results suggest that two simple MR perfusion studies before and early in therapy can offer important information on treatment outcome within the first 2 weeks of radiation therapy before response is evident by clinical examination. High tumor perfusion before therapy and increasing or persistent high perfusion early during the course of therapy appear to be favorable signs. High perfusion suggests a high blood and oxygen supply to the tumor. The increase in tumor perfusion seen in some patients early during radiation therapy suggests improved oxygenation of previously hypoxic cells following early cell kill. Radiation therapy is more effective in eradicating these tumors, resulting in improved local control. Our technique may be helpful in identifying early-while more aggressive therapy can still be implemented-those patients who respond poorly to conventional radiation therapy.

Neurotoxic esterase: characterization of the solubilized enzyme and the conditions for its solubilization from chicken brain microsomal membranes with ionic, zwitterionic, or nonionic detergents.

Neurotoxic esterase (NTE) is a membrane-bound protein found in highest concentration in brain and lymphocytes. The enzyme has no known physiological function, but its organophosphorylation and aging in neural tissue are thought to trigger the pathogenesis of organophosphorus-induced delayed neuropathy (OPIDN). Solubilization of NTE from microsomal membranes from hen or chick brain was studied with ten detergents encompassing ionic, zwitterionic, or nonionic types. Corrected yields of NTE solubilized over a range of [detergent]/[protein] ratios were determined by dividing the activity not sedimenting in detergent at 100,000 g for 60 min at 4 degrees by the activity in the original microsomal fraction with no detergent present. Highest corrected yields were obtained with sodium cholate (44%), Triton X-100 (48%), and nonyl-GPS (57%). Partial loss of NTE activity occurred in the presence of detergent which could be prevented by the inclusion of asolectin in the solubilization preparation. NTE could not be solubilized by omitting detergent or by substituting 2 M NaCl for detergent. Mipafox pI50 values obtained from complete titration curves carried out on NTE solubilized in Triton X-100, sodium cholate, or sodium cholate/asolectin were indistinguishable from the value for native enzyme from brain homogenate. These results indicate that NTE exhibits the properties of an integral membrane protein with lipid dependence. The enzyme can be solubilized in good yield with a variety of detergents with retention of its characteristic differential inhibition by paraoxon and mipafox, a necessary prelude to bulk purification of the enzymatically active protein.