Mistaken identity of widely used esophageal adenocarcinoma cell line TE-7.

Cancer of the esophagus is the seventh leading cause of cancer death worldwide. Esophageal carcinoma cell lines are useful models to study the biological and genetic alterations in these tumors. An important prerequisite of cell line research is the authenticity of the used cell lines because the mistaken identity of a cell line may lead to invalid conclusions. Estimates indicate that up to 36% of the cell lines are of a different origin or species than supposed. The TE series, established in late 1970s and early 1980s by Nishihira et al. in Japan, is one of the first esophageal cancer cell line series that was used throughout the world. Fourteen TE cell lines were derived from human esophageal squamous cell carcinomas and one, TE-7, was derived from a primary esophageal adenocarcinoma. In numerous studies, this TE-7 cell line was used as a model for esophageal adenocarcinoma because it is one of the few esophageal adenocarcinoma cell lines existing. We investigated the authenticity of the esophageal adenocarcinoma cell line TE-7 by xenografting, short tandem repeat profiling, mutation analyses, and array-comparative genomic hybridization and showed that cell line TE-7 shared the same genotype as the esophageal squamous cell carcinoma cell lines TE-2, TE-3, TE-12, and TE-13. In addition, for more than a decade, independent TE-7 cultures from Japan, United States, United Kingdom, France, and the Netherlands had the same genotype. Examination of the TE-7 cell line xenograft revealed the histology of a squamous cell carcinoma. We conclude that the TE-7 cell line, used in several laboratories throughout the world, is not an adenocarcinoma, but a squamous cell carcinoma cell line. Furthermore, the cell lines TE-2, TE-3, TE-7, TE-12, and TE-13 should be regarded as one single squamous cell carcinoma cell line.

Evoked potential latency change with age suggests differential aging of primary somatosensory cortex.

The latencies of the first two cortical peaks in the somatosensory evoked potential were examined in subjects of various ages. Recent work on specialization of primary sensory cortex in primates implicates the cortical site of origin of the second cortical peak, P25, in the selective sensory losses of old age. The latency of the P25 peak changed significantly with age. The latency of the preceeding N20 peak, also of cortical origin but originating from a different site, showed no significant age-related change. Sex differences were present in both N20 and P25 latencies but were independent of the age effect in the latter. Our results provide electrophysiological evidence for differential aging of anatomically separate areas of somatosensory cortex.

Effect of alcohol consumption on state anxiety changes in male and female nonalcoholics.

Ten male and 10 female nonalcoholic college students were given drinks having alcohol levels of 0, 0.5, 0.8, and 1.2 g/kg. They were then given four complex psychomotor tests, immediately before and after which they were given the Spielberger State Anxiety Inventory, and asked to rate their performance on a five-point scale. Mean anxiety change scores were -.90, .75, 4.75, and 5.55 for the four alcohol doses, respectively. There was no significant correlation between anxiety change and actual performance on the visual vigilance task, but for males there was a significant correlation between anxiety change and perceived level of impairment.

Abnormal sensory evoked potentials in amyotrophic lateral sclerosis.

We have reviewed sensory evoked potential (EP) findings in 17 patients with amyotrophic lateral sclerosis (ALS). Somatosensory EPs were abnormal in 7 of 16 patients after lower-extremity stimulation and in 2 of 16 patients after upper-extremity stimulation. Brainstem auditory EP abnormalities were found in 2 of 12 patients. No abnormalities were noted on pattern reversal visual EPs in 12 patients. Overall, 47% of all ALS patients studied had at least one EP abnormality. EP evidence of CNS sensory dysfunction in ALS is more frequent than that noted clinically or pathologically and offers further support to previous observations of sensory system involvement in ALS.

Intraoperative brainstem auditory evoked potentials: significant decrease in postoperative morbidity.

Evoked potentials are commonly used for intraoperative monitoring of neural tissue under surgical threat despite the lack of unequivocal evidence demonstrating its effectiveness in preventing neural injury. This study retrospectively compares the auditory morbidity of posterior fossa microvascular decompressive surgery before and after the introduction of intraoperative brainstem auditory evoked potentials (BAEPs). All patients underwent a similar operative procedure performed by a single surgeon. The two groups were comparable with regards to age, sex, and indications for surgery. In the nonmonitored group, auditory morbidity had not declined with increasing experience of the surgeon. Ten of 152 patients (6.6%) suffered a profound hearing loss in the nonmonitored group. In the monitored group, none of 70 patients suffered a profound hearing loss. We attribute this significant decline (p = 0.02) in morbidity to the introduction of intraoperative BAEPs. We believe this to be the first demonstration of a significant decrease in operative morbidity directly associated with the use of intraoperative evoked potential monitoring.

Ocular bobbing in metabolic encephalopathy: clinical, pathologic, and electrophysiologic study.

A patient with atypical ocular bobbing resulting from metabolic encephalopathy is described. Neurologic examination showed no signs of brainstem dysfunction, and postmortem examination failed to disclose any changes in sites associated with ocular bobbing in other reports. However, brainstem auditory evoked responses showed evidence of bilateral dysfunction of brainstem white matter. This is the first demonstration of functional disturbance in brainstem loci that are thought to be responsible for the infrequently observed ocular bobbing in metabolic encephalopathy.

Daytime functioning and nighttime sleep before, during, and after a 146-hour tennis match.

Two adult males (ages 31 and 35 years) were studied while they participated in a week-long marathon tennis match under conditions of extreme sleep restriction (4-5 h reductions per night). Polysomnographic monitoring was conducted on the two nights prior to the marathon, continuously throughout the match, and on two recovery nights. In addition, measures of daytime sleepiness, mood state, and cognitive performance were obtained during the course of the study. Despite undergoing marked sleep restriction, both players continued to obtain their usual (baseline) amounts of slow wave sleep throughout the marathon. Both players showed a gradually increasing tendency toward daytime dozing across the first few days of the marathon. This tendency decreased on the fifth day but increased again on the sixth day of the match. Also, both players showed a pre- to postmatch decline on some cognitive measures. However, the players differed markedly in their ratings of sleepiness, mood ratings, recovery sleep patterns, and endurance with respect to the demands of the match. Results appear to be consistent with previous laboratory studies in documenting the primacy of the "slow wave sleep drive." Given the marked differences observed between the players, research designed to identify factors that predict response to sleep loss seems to be warranted.

Sleep variability across consecutive nights of home monitoring in older mixed DIMS patients.

Twenty patients with difficulties initiating and maintaining sleep (DIMS) were monitored in their homes for three consecutive nights using ambulatory polysomnography (PSG). Following each night of monitoring, patients provided subjective ratings of sleep disturbance and tolerance of the PSG equipment. Friedman analyses of variance performed on the objective and subjective parameters showed that the sample, as a whole, evidenced no systematic first night effects (FNE) in response to monitoring. Inspection of the data from each individual subject, nevertheless, showed that half of the sample did experience multiple FNE. Further, several scales from the Minnesota Multiphasic Personality Inventory discriminated those patients who showed multiple FNE from those who did not. However, far more striking was the finding that clinically and statistically significant intrasubject variability across nights was observed for each sleep parameter measured. Given this finding, a single ambulatory PSG study may not fully convey the nature of the sleep disturbance experienced by the DIMS patient even when FNE are absent. We thus, recommend multiple ambulatory sleep studies for those clinical and research situations in which it is necessary to document patients' night-to-night sleep variability. In contrast, when the goal of the PSG study is that of determining a sleep diagnosis, a single ambulatory study, in combination with other clinical data, may be sufficient.

Two methods of scoring sleep with the Oxford Medilog 9000: comparison to conventional paper scoring.

This study evaluated two methods of scoring taped polysomnographic data directly on the Medilog 9000 scanner: (a) screen-by-screen scoring, and (b) rapid screen scoring. Sixteen overnight polysomnograms recorded on Medilog 9000 recorders were scored using the above two methods and were also printed on paper for conventional paper scoring. Interscorer agreement was 87.8% for paper scoring, 85.5% for screen-by-screen scoring, and 84.2% for rapid screen scoring. Comparison of screen-by-screen scoring with paper scoring revealed small absolute deviations and correlations of r greater than 0.90 for all sleep parameters, with the exception of brief (less than 2 min) awakenings (r = 0.69). Rapid screen scoring resulted in slightly lower correlations and greater deviations from paper scoring on several sleep parameters, but appeared acceptable for most clinical purposes and greatly reduced the required scoring time. Although some statistically significant differences between scoring methods were observed, the size of effect was small and of doubtful clinical importance. These findings suggest that polysomnographic data recorded on Medilog 9000 recorders can be reliably and accurately scored on the Medilog scanner, obviating the laborious task of printing the taped data on paper.

Periodic limb movement variability in older DIMS patients across consecutive nights of home monitoring.

Older difficulty initiating and/or maintaining sleep (DIMS) patients who met criteria for periodic limb movement disorder (PLMD) were monitored for three consecutive nights in their homes using ambulatory polysomnography (PSG). Correlational analyses of the group data suggested little night-to-night variability in either movement indices or movement-related arousal indices for this sample. However, within-subjects comparisons suggested considerable variability in these indices and other sleep measures across nights. Nevertheless, for most subjects, the variability noted for these indices appeared to have little effect on PLMD severity classification or clinical treatment decisions derived from blind examinations of PSGs. Further, the initial PSG study generally led to a representative severity classification and clinical decision. Additional research is needed to determine the generalizability of these results to younger subjects, patients with complaints of excessive somnolence and other methods of home PSG monitoring.

Polysomnographic assessment of DIMS: empirical evaluation of its diagnostic value.

This investigation examined the diagnostic value of polysomnography (PSG) for evaluating disorders of initiating and maintaining sleep (DIMS). The sample consisted of 100 outpatients who presented to the Duke Sleep Disorders Center with a complaint of chronic insomnia. All patients were given comprehensive medical, psychiatric, behavioral, and ambulatory PSG evaluations. Sleep disorder diagnoses were assigned using the criteria of the Association of Sleep Disorders Centers. Overall, PSG yielded important diagnostic information in 65% of the sample: 34% were given a primary sleep disorder diagnosis that was heavily dependent on PSG data [periodic movements of sleep (PMS) = 25%, apnea = 3%, and subjective insomnia = 6%]; 15% were given a secondary diagnosis of one of these three disorders; and PSG ruled out suspected PMS in 9% and sleep apnea in 7% of the sample. Patients greater than 40 years of age had a significantly higher rate of positive PSG findings than younger patients. Using only the clinical exam, two experienced sleep clinicians were able to predict only 14 of 25 PMS cases and one of three cases of sleep apnea. Based on these data, we suggest using PSG routinely with older insomniacs and with younger patients who fail initial treatment.

Efficacy and side effects of flunitrazepam and pentobarbital in severely insomniac patients.

One hundred thirty-seven current or prospective recipients of hypnotics were screened to obtain a sample of 12 severely insomniac patients for a study concerning efficacy and side effects of 2 mg flunitrazepam and 100 mg pentobarbital as hypnotics. During the baseline period, these 12 subjects showed wide intraindividual variability of sleep and performance. This variability was not reduced by the hypnotics, which on the average did not adversely affect performance. Flunitrazepam, but not pentobarbital, slightly reduced sleep latency. Neither hypnotic prolonged sleep duration or reduced the number of wakings. The generalizability of the results to the population of recipients of hypnotics is discussed.

Efficacy and side effects of flurazepam and a combination of amobarbital and secobarbital in insomniac patients.

Flurazepam, 30 mg, was not more effective in inducing sleep than placebo. Barbiturates (100 mg amobarbital plus 100 mg secobarbital) were more effective in inducing and maintaining sleep than flurazepam or placebo. Contrary to work conducted in the sleep laboratory, the barbiturate hypnotics were still effective on the 14th night. Insomniacs performed poorly on psychomotor tests, but as a group they did not show statistically significant psychomotor impairment after the use of the hypnotics.

Effects of alcohol and flunitrazepam on mood and performance in healthy young men.

Alcohol and flunitrazepam did not have any pharmacokinetic interactions when ingested 30 minutes apart at night. Flunitrazepam, 2.0 mg, but not 0.8 Gm/kg alcohol had a strong deleterious effect on performance shortly after ingestion. The combination of flunitrazepam and alcohol impaired tracking in a divided attention task the following morning.

Limitations of brain stem auditory evoked potentials for intraoperative monitoring during a posterior fossa operation: case report and technical note.

We have encountered an example of the insensitivity of brain stem auditory evoked potentials (BAEPs) for monitoring the brain stem during a posterior fossa operation. The addition of somatosensory evoked potential recording to conventional BAEP protocols is readily accomplished and is likely to improve the sensitivity of intraoperative electrophysiological assessment of brain stem function.

Up and down the spinal cord: intraoperative monitoring of sensory and motor spinal cord pathways.

Monitoring of spinal cord function during certain orthopedic and neurosurgical procedures is done to reduce the likelihood of neurologic complications. This article is based on intraoperative experiences gained at Duke University Medical Center since 1978. Both ascending sensory (up) and descending motor (down) data can be evaluated to assist in improved patient outcomes. Refinements in technique and better understanding of the neural generators of evoked potentials obligate the components to have improved sensitivity and specificity of spinal intraoperative monitoring. An additional improvement has been the intraoperative use of motor evoked potentials. This discussion deals with a description of specific responses obtained following lower-limb mixed nerve stimulation in terms of neural generation, influences of rate and intensity, and anesthetic effects. The techniques and advantages of bipolar epidural recording and stimulation are discussed. Motor tract stimulation via the same epidural electrodes used for recording of sensory components is described. Case reports are presented to emphasize major points.

A review of electroencephalographic features of normal sleep.

The electrographic features of sleep have been studied intensively using both routine electroencephalography and polysomnography. The two sections of this paper describe and illustrate the major characteristics of sleep physiology and associated clinical electroencephalography. In the first section, criteria for definition of sleep stages are presented and correlated with the phasic and tonic physiological events noted to occur as a function of sleep stage. The phylogeny and ontogeny of sleep are discussed as well as the neurophysiological mechanisms that may underlie sleep control. The second section presents a clinically oriented description of the patterns and events of the sleep electroencephalogram as seen in a normal adult and pediatric population.

Somatosensory evoked potentials and the dorsal column myth.

Somatosensory evoked potentials (SEPs) are believed to travel primarily if not totally over the dorsal column (DC) system. The modalities of joint position sense and vibration are said to be mediated by the DCs. The authors cite classic and recent literature as well as their own work to reveal a lack of consistent agreement between clinical sensory (neurological examination) and electrophysiological (SEP) data regarding DC dysfunction. Documentation of this discrepancy is presented, and potential causes are examined. The authors conclude that, despite the classic tenets, there is not testable modality specific to the DC. Instead, there is likely a transmission of several proprioceptive modalities, not limited to the DC, that ascend variously in the spinal cord and are integrated at a higher level to produce somesthetic appreciation.

Ambulatory polysomnography: technical aspects and normative values.

Ambulatory polysomnographic (APSG) assessment of sleep disorders is now possible, but the technique of APSG is sufficiently different from in-laboratory PSG that normative data from in-laboratory PSG may not apply to APSG. This paper reviews the technical aspects of APSG and presents normative APSG data from 20 older healthy males. Subjects underwent medical and psychiatric screening before completing APSG in their homes. Total sleep time and the rapid-eye-movement sleep latency (RL) were both shorter than those reported by others using traditional in-laboratory techniques. The shorter total sleep may be related to behaviors at home that impinge upon sleep. The shorter RL may be related to differences in calculation methods. Periodic limb movements were common in our subjects but did not contribute to sleep disturbance. We conclude that APSG is sufficiently different from traditional PSG as to warrant collection of a large normative data base.

Ambulatory cassette polysomnography: findings from a large cohort of drug-free insomnia patients.

Technology for conducting ambulatory polysomnography (APSG) has been available for more than a decade, but relatively few studies have used this technology to study the sleep of subjects in their usual home sleeping environments. Herein we suggest the usefulness of this technology for the study of normal sleepers and insomniacs, and we report our APSG findings with a large cohort (n = 117) of drug-free insomnia outpatients. All patients completed a sleep-history questionnaire, a clinical interview with a sleep-disorders clinician, and one night of APSG in their homes. Most sleep parameters derived were consistent with previously reported laboratory PSG findings for insomniacs, except that values of rapid-eye-movement sleep latencies were generally shorter than typically found in laboratory studies. Moreover, results showed that APSG served to differentiate major age groups and diagnostic subtypes within our larger sample, and patient tolerance for APSG was within acceptable limits. We conclude that APSG is a useful technique for evaluating insomnia complaints.