Citations

The inclusion of neurocognitive end points in clinical trials of patients with CNS tumors is increasing. Neurocognitive end points are used to understand what cognitive problems exist before treatment to establish a baseline by which the effect of treatment is judged, and to determine whether different treatment regimens improve neurocognitive function due to better tumor control, slow expected neurocognitive deterioration due to the tumor, or have more or less short- and long-term neurotoxicity. However, the use of neurocognitive end points in clinical trials for patients with CNS tumors is in its infancy, so that long-term outcomes are difficult to predict and the ability to determine the effects of different agents and treatment approaches is scant. Including this aspect of patient evaluation in addition to survival and time to tumor progression will yield better risk-versus-benefit assessments as well as provide a basis for improving interventions.

The basis for ethnicity-related distinctions in gonadotropin secretion are unknown but may have important populational and physiological implications. In male contraceptive trials, exogenous testosterone and progestins suppress spermatogenesis to a greater degree in Asian than Caucasian men. In addition, iv infusion of testosterone inhibits LH release more in Asian than Caucasian volunteers. We test the converse postulate that experimental reduction of androgen-dependent negative feedback by way of the steroidogenic inhibitor combination ketoconazole/dexamethasone will unveil ethnicity-related mechanisms of regulated LH secretion in young men. LH release was monitored by sampling blood every 10 min for 24 h followed by immunoradiometric assay, model-free pulse detection, an entropy (regulatory) statistic, and cosine regression. Statistical comparisons revealed that healthy young Asian and Caucasian men maintain comparable baseline concentrations of LH, testosterone, estradiol, SHBG, and molar testosterone to SHBG ratios. In contrast, the two ethnic groups differ prominently in each of basal, pulsatile, entropic, and 24-h rhythmic LH adaptations to short-term androgen withdrawal. Therefore, we postulate that physiological nonuniformity of sex steroid-dependent negative feedback in particular may contribute to populational diversity in LH regulation.

Abstract Background. Small bowel adenocarcinoma is a rare gastrointestinal malignancy that is treated primarily with surgery. Even with optimal resection, however, survival is poor and recurrences are common. Response rates to palliative combination chemotherapy are low, and the median duration of survival for metastatic disease is less than 1 year. This study aimed to document the response rate and survival time for patients with advanced small bowel adenocarcinoma who were not surgically curable and were treated with a regimen of 5-fluorouracil (5-FU), mitomycin C (Mutamycin®; Bristol-Myers Squibb; Princeton, NJ), and doxorubicin (Adriamycin®; Bedford Laboratories; Bedford, OH), the FAM regimen. Methods. This multi-institutional study was performed by the Eastern Cooperative Oncology Group (ECOG). Between November, 1983 and December, 1985, 39 patients with advanced or recurrent disease were enrolled. Chemotherapy was given as follows: 5-FU, 600 mg/m2 on days 1, 8, 29 and 36; mitomycin C, 10 mg/m2 on day 1; and doxorubicin, 30 mg/m2 on days 1 and 29. Eligibility criteria included an ECOG performance status score of 0–2, measurable disease, and adequate baseline organ function. Prior chemotherapy was allowed. Response was measured by examination and imaging techniques. Survival time and time to progression were evaluated by the method of Kaplan and Meier, and these outcomes were stratified by clinical and laboratory covariates. Results. Of the 39 evaluated patients, 38 were eligible and 36 were evaluable for response. Grade 3–5 toxicities were experienced by a total of 26 patients (20 grade 3, 5 grade 4, 1 grade 5). The most common adverse events were neutropenia and vomiting. Responses were seen in a total of seven patients (2 complete responses, 5 partial responses), for a response rate of 18.4% (95% confidence interval of 7.8%–34.4%). The median survival time was 8 months. Conclusions. The FAM regimen was active and tolerable for patients with advanced small bowel adenocarcinoma; however, the results were no better than those seen with other chemotherapy combinations.

Mutations in the MEN1 gene are associated with the multiple endocrine neoplasia syndrome type 1 (MEN1), which is characterized by parathyroid hyperplasia and tumors of the pituitary and pancreatic islets. The mechanism by which MEN1 acts as a tumor suppressor is unclear. We have recently shown that menin, the MEN1 protein product, interacts with mixed lineage leukemia (MLL) family proteins in a histone methyltransferase complex including Ash2, Rbbp5, and WDR5. Here, we show that menin directly regulates expression of the cyclin-dependent kinase inhibitors p27 Kip1 and p18 Ink4c . Menin activates transcription by means of a mechanism involving recruitment of MLL to the p27 Kip1 and p18 Ink4c promoters and coding regions. Loss of function of either MLL or menin results in down-regulation of p27 Kip1 and p18 Ink4c expression and deregulated cell growth. These findings suggest that regulation of cyclin-dependent kinase inhibitor transcription by cooperative interaction between menin and MLL plays a central role in menin's activity as a tumor suppressor.

Long QT syndrome is a malfunction of cardiac ion channels resulting in impaired ventricular repolarization that can lead to a characteristic polymorphic ventricular tachycardia known as torsades de pointes. Stressors, by increasing sympathetic tone, and drugs can provoke torsade de pointes, leading to syncope, seizures, or sudden cardiac death in these patients. Beta blockade, implantation of cardioverter defibrillators, and left cardiac sympathetic denervation are used in the treatment of these patients. However, these treatment modalities do not guarantee the prevention of sudden cardiac death. Certain drugs, including anesthetic agents, are known to contribute to QT prolongation. After reviewing the literature the authors give recommendations for the anesthetic management of these patients in the perioperative period.

Background In airway smooth muscle (ASM), volatile anesthetics deplete sarcoplasmic reticulum (SR) Ca(2+) stores by increasing Ca(2+) "leak." Accordingly, SR replenishment becomes dependent on Ca(2+) influx. Depletion of SR Ca(2+) stores triggers Ca(2+) influx via specific plasma membrane channels, store-operated Ca(2+) channels (SOCC). We hypothesized that anesthetics inhibit SOCC triggered by increased SR Ca(2+) "leak," preventing SR replenishment and enhancing ASM relaxation. Methods In porcine ASM cells, SR Ca was depleted by cyclopiazonic acid or caffeine in 0 extracellular Ca(2+), nifedipine and KCl (preventing Ca(2+) influx through L-type and SOCC channels). Extracellular Ca(2+) was rapidly introduced to selectively activate SOCC. After SOCC activation, SR was replenished and the protocol repeated in the presence of 1 or 2 minimum alveolar concentration halothane, isoflurane, or sevoflurane. In other cells, characteristics of SOCC and interactions between acetylcholine (Ach) and volatile anesthetics were examined. Results Cyclopiazonic acid produced slow SR leak, whereas the caffeine response was transient in ASM cells. Reintroduction of extracellular Ca(2+) rapidly increased [Ca(2+)]i. This influx was insensitive to nifedipine, SKF-96365, and KBR-7943, inhibited by Ni and blockade of inositol 1,4,5-triphosphate-induced SR Ca(2+) release, and enhanced by ACh. Preexposure to 1 or 2 minimum alveolar concentration halothane completely inhibited Ca(2+) influx when extracellular Ca(2+) was reintroduced, whereas isoflurane and sevoflurane produced less inhibition. Only halothane and isoflurane inhibited ACh-induced augmentation of Ca(2+) influx. Conclusion Volatile anesthetics inhibit a Ni/La-sensitive store-operated Ca(2+) influx mechanism in porcine ASM cells, which likely helps maintain anesthetic-induced bronchodilation.

Background Volatile anesthetics relax airway smooth muscle (ASM) by altering intracellular Ca2+ concentration ([Ca2+]i). The authors hypothesized that relaxation is produced by decreasing sarcoplasmic reticulum Ca2+ content via increased Ca2+ "leak" through both inositol trisphosphate (IP3) and ryanodine receptor channels. Methods Enzymatically dissociated porcine ASM cells were exposed to acetylcholine in the presence or absence of 2 minimum alveolar concentration (MAC) halothane, and IP3 levels were measured using radioimmunoreceptor assay. Other cells were loaded with the Ca2+ indicator fluo-3 and imaged using real-time confocal microscopy. Results Halothane increased IP3 concentrations in the presence and absence of acetylcholine. Inhibition of phospholipase C blunted the IP3 response to halothane. Exposure to 2 MAC halothane induced a transient [Ca2+]i response, suggesting depletion of sarcoplasmic reticulum Ca2+. Exposure to 20 microM Xestospongin D, a cell-permeant IP3 receptor antagonist, resulted in a 45+/-13% decrease in the [Ca2+]i response to halothane compared with halothane exposure alone. In permeabilized cells, Xestospongin D or 0.5 mg/ml heparin decreased the [Ca2+]i response to halothane by 65+/-13% and 68+/-22%, respectively, compared with halothane alone. In both intact and permeabilized cells, 20 microM ryanodine blunted the [Ca2+]i response to halothane by 32+/-13% and 39+/-21%, respectively, compared with halothane alone. Simultaneous exposure to Xestospongin D and ryanodine completely inhibited the [Ca2+]i response to halothane. Conclusions The authors conclude that halothane reduces sarcoplasmic reticulum Ca2+ content in ASM cells via increased Ca2+ leak through both IP3 receptor and ryanodine receptor channels. Effects on IP3 receptor channels are both direct and indirect via elevation of IP3 levels.

AbstractSummary: We report identification of short‐chain acyl‐CoA dehydrogenase (SCAD) deficiency in a 12‐year‐old boy who suffered from recurrent attacks of vomiting once or twice a year from infancy. Growth and development were normal and there were no muscular symptoms. Metabolic screening was performed during a hospitalization at 8 years of age and revealed an increased excretion of ethylmalonic acid (EMA; 45–80 mmol/mol creatinine, normal 0.2–6.6), suggesting a degradation defect of short‐chain fatty acids. An increased n‐butyrylcarnitine was found in freshly collected serum (0.9 µmol/L; normal <0.4) but not in dry blood spots. Neither of the frequent SCAD gene variants 625G>A and 511C>T was present, but direct sequencing of the promoter and coding regions of the SCAD gene revealed that the patient had mutations on both alleles: 417G>C (Trp115Cys) and 1095G>T (Gln341His). Neither mutation has been described before in compound heterozygosity or homozygosity. Enzymatic investigations subsequently confirmed a defect of SCAD in both fibroblasts and muscle extracts. Furthermore, expression studies of both mutations demonstrated impaired enzyme function or structure. To our knowledge, this case is the first description of a patient with proven SCAD deficiency presenting with recurrent emesis but without other symptoms, and emphasizes the wide clinical phenotype of this disorder.