Leo Katz

Scalp recorded auditory evoked potentials and sonomotor responses: An evaluation of components and recording techniques ☆

Abstract Early (0–8 msec), middle (8–50 msec) and long (50–500 msec) latency auditory evoked potentials (AEPs) were recorded from the scalp, ear, nose and mastoid regions of normal adult subjects using a balanced sternovertebral non-cephalic reference system. This study intended to differentiate neurogenic from myogenic components. Components judged to be neurogenic were greatest in amplitude at frontocentral scalp recording locations and were recorded during sleep. Some of these potentials were also recorded from the ear, mastoid and nose which suggests that these locations are often not ideal reference sites for recording AEPs. Certain scalp recorded middle and long latency AEPs were characterized by progressive shifts in their peak latencies in the sagittal and coronal planes. This “traveling wave” phenomenon suggests that these potentials arise in multiple spacially fixed cerebral generators. Components judged to be myogenic had latencies of 8–60 msec, were widely distributed over the scalp and were of greatest amplitude in relationship to actively contracting scalp muscle groups. One of these potentials, the post-auricular response, was recorded from the ear, mastoid and postauricular region. Except for the post-auricular response, these potentials were not observed in sleeping subjects. This suggests that middle latency AEPs can be recorded free of evoked myogenic contamination in normal adults during sleep if the recording electrode is not placed in the vicinity of the ear.

Efficacy of morning-only compared with split-dose polyethylene glycol electrolyte solution for afternoon colonoscopy: a randomized controlled single-blind study.

OBJECTIVES:Administering a purgative close to the time of colonoscopy is optimal for cleansing. The aim of this study was to compare the efficacy and tolerability of morning-only (AM-only) polyethylene glycol electrolyte solution (PEG-ELS) to split-dose (PM/AM) PEG-ELS for afternoon colonoscopy.METHODS:This was a single-center, prospective, randomized, investigator-blinded, non-inferiority study comparing AM-only to PM/AM PEG-ELS for afternoon outpatient colonoscopy. The primary end point was whole colon prep adequacy. Tolerance and polyp detection were secondary outcomes.RESULTS:Overall, 125 patients were randomized and 9 withdrew without taking any prep. Of 116 analyzed, 62 received AM-only prep and 54 received PM/AM prep. The whole colon prep was adequate in 92% in the AM-only group vs. 94% in the PM/AM group (95% lower confidence limit, LCL, for the difference=−11.3%, non-inferiority P=0.013), whereas the right colon prep was adequate in 93 and 92%, respectively (95% LCL=−7.8%, non-inferiority P=0.003). Polyp detection was greater, and not inferior, in the AM-only group (mean=1.57 vs. 0.94 polyps/patient, non-inferiority P=0.007). The overall incidence of adverse events was not significantly different between the two groups (P=0.273), but the AM-only group had lower incidence of abdominal pain (P=0.024). The AM-only group also had better sleep quality (P=0.007) and less interference with the previous workday (P=0.019).CONCLUSIONS:AM-only and PM/AM PEG-ELS are clinically equivalent with respect to cleansing efficacy and polyp detection. AM-only prep was associated with a lower incidence of abdominal pain, superior sleep quality, and less interference with workday before colonoscopy.

Body position affects recumbent postprandial reflux.

There is a lack of consensus as to whether there is a difference in the amount of gastroesophageal reflux when lying with the right versus the left side down. In an attempt to answer this question we conducted a two-part study. The first consisted of a questionnaire distributed to 103 gastroenterologists with a special interest in the esophagus. The second was a randomized study in 20 normal subjects given a high-fat meal to induce reflux. Postprandial reflux was monitored by esophageal pH testing for 4 h after random assignment to either the left or right lateral decubitus position (left or right side down) on different days. Of the 87 gastroenterologists responding to our survey, 45 were uncertain as to which position was associated with worse reflux. Among the 42 who did specify, 27 (64%) favored the right lateral decubitus position as associated with more reflux symptoms. The direct comparison of the two positions demonstrated that the total amount of reflux time was significantly (p < 0.05) greater with subjects in the right decubitus position (231 min) than in the left (117 min). Although total episodes of reflux were greater when lying on the right side (227), compared with the left (198), the difference was not significant. In addition, average overall acid clearance was significantly (p < 0.001) prolonged with right side down (0.77 +/- 0.14 min/episode) compared with left side down (0.29 +/- 0.08 min/episode).

Computer analysis of EEG activity in dementia of the Alzheimer's type and Huntington's disease

Computer analysis of the EEG was obtained in the course of evaluation of 35 patients with Dementia of the Alzheimers Type (DAT) and Huntingtons disease (HD), and compared to 20 age-matched normal controls. On-line computer analysis of the EEG consisted of: 1) compressed spectral array (CSA) displays (2-6 channels); 2) relative frequency power (4 bands) and 3) an averaged frequency power function [( alpha/alpha + theta power (microV 2)] X 100 = % EEG Power function). Frequency power reflected increased theta, and reduced alpha components, in patient groups. Significant correlation was obtained between % EEG Power function, and clinical stage of dementia. This function correctly identified 17/25 DAT, and 7/10 HD patients, and gave additional quantification to the primary EEG.

A validation study of 3 grading systems to evaluate small-bowel cleansing for wireless capsule endoscopy : a quantitative index, a qualitative evaluation, and an overall adequacy assessment

BACKGROUND Capsule endoscopy (CE) is a powerful tool for evaluating the small bowel. Assessment of small-bowel cleansing for CE is an essential quality measure. OBJECTIVE Our purpose was to validate 3 new scales that grade small-bowel cleansing for CE. DESIGN Prospective, randomized, single-center study. SETTING Tertiary university hospital. INTERVENTION Five experienced capsule endoscopists read 40 CEs twice, separated by 1 month, to grade small-bowel cleansing on 3 scales-quantitative index (QI; 0-10), qualitative evaluation (QE; poor, fair, good, excellent), and overall adequacy assessment (OAA; inadequate, adequate). The QI and QE evaluated both the entire and distal small bowel. Investigators received no prior training in these scales. MAIN OUTCOME MEASUREMENTS Intraclass correlation coefficients to assess intraobserver (test-retest) and interobserver reliability. PATIENTS Forty patients who underwent 1 CE between June 2005 and May 2006 and who satisfied entry criteria. RESULTS Intraobserver reliability was moderate to substantial for the QI (0.60-0.66), moderate for the OAA (0.56), and fair to moderate for the QE (0.37-0.47). Interobserver scores were lower: QI and OAA moderate (0.47-0.52, 0.41, respectively) and slight to fair for the QE (0.20-0.24). QI scores for the entire and distal small bowel were highly correlated for each reader (0.57-0.87), and distal small-bowel scores were lower by 1.3 points, indicating poorer cleansing (P = .001). A dichotomized QE of excellent/good versus fair/poor had moderate to substantial intraobserver and interobserver reliability (0.58-0.66, 0.41-0.49, respectively). There was a strong and highly significant association among all 3 scales (P < .001 between QI and both QE and OAA). CONCLUSION We have described and validated 3 scales for grading small-bowel cleansing for CE. An evaluation of small-bowel cleansing should be routinely incorporated into the CE report.

Is Single-Cell Apoptosis Sufficient for the Diagnosis of Graft-Versus-Host Disease in the Colon?

Low-grade lesions of graft-versus-host disease (GVHD) in the colon are not uncommon. To determine if minimal diagnostic criteria can be established in such biopsies, we correlated histologic findings with clinical history and investigated the role of endoscopy and electron microscopy in establishing GVHD. About 85 colonic biopsies that were histologically consistent with GVHD from 47 bone-marrow transplant recipients were reviewed retrospectively. Of nine cases showing only a single apoptotic cell in the intestinal epithelium, only four lacked any confounding factors of GVHD. These cases, while too few to assess the utility of finding one apoptotic cell with statistical significance, appear to support the idea that in the appropriate clinical setting, a single apoptotic cell could be reported as possibly representing early GVHD. Endoscopic findings did not reliably correlate with histology. Although electron microscopy can be a useful adjunct, it does not contribute to the diagnosis of GVHD.

The Effect on Colon Visualization During Colonoscopy of the Addition of Simethicone to Polyethylene Glycol-Electrolyte Solution: A Randomized Single-Blind Study

OBJECTIVES:Colonic bubbles associated with polyethylene glycol-electrolyte solution (PEG-ELS) are common and obscure mucosal visualization. This study aimed to determine whether adding simethicone decreases the incidence of bubbles.METHODS:Prospective, single-blind, randomized comparison of split dose PEG-ELS vs. PEG-ELS+simethicone (PEG-S) for outpatient colonoscopy. Bubble severity for colonic segments was assessed on withdrawal as A=no/minimal bubbles, B=moderate bubbles/interfere with detecting 5 mm polyp, C=severe bubbles/interfere with detecting 10 mm polyp. Primary end point was Grade B or C bubbles in any colon segment. Secondary end points were cleansing quality, incidence and severity of side effects, and polyp detection.RESULTS:One hundred and thirty nine patients enrolled; 13 withdrew before colonoscopy. Of 123 patients evaluated, 62 took PEG-S and 61 PEG-ELS. The incidence of grade B or C bubbles was much lower with PEG-S compared with PEG-ELS (2% vs. 38%; P=0.001). Overall cleansing (excellent or good) quality was not significantly different for either the whole colon (89% PEG-ELS, 94% of PEG-S, P=0.529) or right colon (88% PEG-ELS, 94% PEG-S, P=0.365). More PEG-S patients had excellent rather than good preps (whole colon 53% vs. 28%, P=0.004; right colon 53% vs. 35%, P=0.044). Need for any flushing was less with PEG-S (38% vs. 70%, P=0.001). The groups were not significantly different with respect to total procedure and withdrawal times, incidence or severity of side effects, or number of polyps/patient or adenomas/patient.CONCLUSIONS:Adding simethicone to PEG-ELS effectively eliminates bubbles, substantially reduces the need for flushing, and results in more excellent preparations.

Randomised clinical trial: polyethylene glycol 3350 with sports drink vs. polyethylene glycol with electrolyte solution as purgatives for colonoscopy – the incidence of hyponatraemia

Polyethylene glycol 3350 plus sports drink (PEG‐SD) is a hypo‐osmotic purgative commonly used for colonoscopy, though little safety data are available.

Bioactivity of Oral Linaclotide in Human Colorectum for Cancer Chemoprevention

Guanylate cyclase C (GUCY2C) is a tumor-suppressing receptor silenced by loss of expression of its luminocrine hormones guanylin and uroguanylin early in colorectal carcinogenesis. This observation suggests oral replacement with a GUCY2C agonist may be an effective targeted chemoprevention agent. Linaclotide is an FDA-approved oral GUCY2C agonist formulated for gastric release, inducing fluid secretion into the small bowel to treat chronic idiopathic constipation. The ability of oral linaclotide to induce a pharmacodynamic response in epithelial cells of the colorectum in humans remains undefined. Here, we demonstrate that administration of 0.87 mg of oral linaclotide daily for 7 days to healthy volunteers, after oral colon preparation with polyethylene glycol solution (MoviPrep), activates GUCY2C, resulting in accumulation of its product cyclic (c)GMP in epithelial cells of the cecum, transverse colon, and distal rectum. GUCY2C activation by oral linaclotide was associated with homeostatic signaling, including phosphorylation of vasodilator-stimulated phosphoprotein and inhibition of proliferation quantified by reduced Ki67-positive epithelial cells. In the absence of the complete oral colonoscopy preparation, linaclotide did not alter cGMP production in epithelial cells of the colorectum, demonstrating that there was an effect related to the laxative preparation. These data show that the current FDA-approved formulation of oral linaclotide developed for small-bowel delivery to treat chronic idiopathic constipation is inadequate for reliably regulating GUCY2C in the colorectum to prevent tumorigenesis. The study results highlight the importance of developing a novel GUCY2C agonist formulated for release and activity targeted to the large intestine for colorectal cancer prevention. Cancer Prev Res; 10(6); 345–54. ©2017 AACR.

Safety of sodium phosphate tablets in patients receiving propofol-based sedation for colonoscopy.

Goals: To compare the incidence of peri-procedure adverse events in patients undergoing colon cleansing with sodium phosphate tablets or polyethylene glycol solution prior to colonoscopy with propofol-based sedation. Background: Propofol is a rapidly acting hypnotic sedative general anesthetic agent increasingly being used for colonoscopy. Although traditionally patients fast overnight prior to a general anesthetic, a new Food and Drug Administration-approved sodium phosphate tablet purgative requires ingestion of 20 tablets with 56 ounces of clear liquid 3 to 5 hours prior to colonoscopy. Study: We retrospectively reviewed 97 outpatients who received propofol-based sedation for colonoscopy. This was a subset of a randomized, investigator-blinded, multicenter trial comparing sodium phosphate tablets with polyethylene glycol. Study data and anesthesia records were reviewed for peri-procedure hemodynamic, cardiac, and pulmonary adverse events as well as the need for hospital admission. Results: There were no statistically significant differences between the 2 groups when analyzed for the development of tachycardia, decrease in mean arterial pressure below 50 mmHg, or a reduction in the mean arterial pressure greater than 30% from the pre-procedure value. No patients in either group experienced hypoxia (oxygen saturation < 90%), excessive regurgitation, pneumonia, or hospital admission. Conclusions: Peri-procedure adverse events occurred rarely and with no increased frequency in patients using the sodium phosphate tablet purgative and receiving propofol-based sedation. The sodium phosphate tablet purgative is safe for patients receiving propofol-based sedation for colonoscopy.