The gravitational field and brain function

The frontal cortex is recognized as the highest adaptive control center of the human brain. The principle of the "frontalization" of human brain function offers new possibilities for brain research in space. There is evolutionary and experimental evidence indicating the validity of the principle, including it's role in nervous response to gravitational stimulation. The gravitational field is considered here as one of the more constant and comprehensive factors acting on brain evolution, which has undergone some successive crucial steps: "encephalization", "corticalization", "lateralization" and "frontalization". The dominating effects of electrical responses from the frontal cortex have been discovered 1) in experiments under gravitational stimulus; and 2) in processes potentially relating to gravitational adaptation, such as memory and learning, sensory information processing, motor programing, and brain state control. A brain research experiment during space flight is suggested to test the role of the frontal cortex in space adaptation and it's potentiality in brain control.

Calcium/phospholipid regulates phosphorylation of a Mr "87k" substrate protein in brain synaptosomes

Depolarization-induced calcium influx into rat cerebral cortex synaptosomes increased the phosphorylation of several synaptosomal proteins as examined by 32Pi incorporation. A phosphopeptide mapping technique involving NaDodSO4/polyacrylamide gels has been used to show that phosphorylation of a Mr 87,000 substrate protein is stimulated by depolarization-induced calcium influx. Phosphorylation of this Mr 87,000 substrate occurred in synaptosomal cytosol and was markedly stimulated by calcium/phosphatidylserine. Calmodulin inhibited this phosphorylation reaction. This substrate for calcium/phospholipid-dependent protein kinase is enriched in and appears to be specific to neurons.

The sensitivity of radiography of the postoperative stomach

The results of radiology and endoscopy were compared in 140 patients who had undergone gastric surgery for ulcer disease. Of 74 patients who were examined with single-contrast radiography, 37 had abnormalities that were demonstrated endoscopically. The radiographic sensitivities in these patients were: gastritis 2/22 (9%); ulcer 3/5 (60%); obstruction 8/8 (100%); and miscellaneous abnormalities 2/2 (100%). The predictive accuracy of a diagnosis of ulcer was 38%. Of the 66 patients who were examined with double-contrast radiography, 33 abnormalities were found with endoscopy. The radiographic sensitivities were: gastritis 3/13 (23%); ulcer 7/10 (70%); obstruction 4/4 (100%); and miscellaneous abnormalities 6/6 (100%). The predictive accuracy of a diagnosis of ulcer was 44%. Radiology appears to be unreliable in diagnosing gastritis and recurrent ulceration in the postoperative stomach. The double-contrast technique does not offer significant improvement over the single-contrast method in evaluating these postoperative problems.

Extent of colonic visualization with the fiberoptic sigmoidoscope

Forty-two patients underwent flexible sigmoidoscopy in the radiology department. After maximal insertion of the sigmoidoscope, a supine abdominal film documented the position of the tip of the instrument. Correlation with barium enema in all patients determined the extent of visualization of the colon relative to the length of insertion of the sigmoidoscope. Insertion to 60 cm was achieved in 31 (74%), 40-59 cm in six (14%), 25-39 cm in three (7%), and under 25 cm in two (5%), with a mean depth of insertion of 54 cm. Full insertion examined the entire sigmoid colon in 14 (45%) of 31 patients. Insertion between 40-59 cm achieved complete sigmoid evaluation in only one (17%) of six patients. Thus, flexible sigmoidoscopy does not necessarily guarantee evaluation of the entire sigmoid colon.

Detection of gastric ulcer: comparison of single- and double-contrast examination

The radiographic sensitivities of single- and double-contrast examinations for detecting gastric ulcer were compared. Single-contrast radiography detected 30 (75%) of 40 endoscopically verified gastric ulcers. Only 56% of ulcers under 5 mm were detected with the single-contrast method, while 88% of those larger were identified. Double-contrast radiography detected 58 (62%) of 93 endoscopically verified gastric ulcers. Only 45% of ulcers under 5 mm were detected with the double-contrast method, while 78% of those larger were identified. Statistically, the probability of ulcer detection was found to be primarily dependent on ulcer size, regardless of the technique used, and no significant difference could be demonstrated between the sensitivities of single- and double-contrast radiography.

Treatment of vincristine-induced ileus with sincalide, a cholecystokinin analog

Sincalide, a synthetic analog of cholecystokinin capable of stimulating bowel motility, has been administered to 12 patients with symptoms and signs of vincristine-induced ileus. Patients were given intravenous infusions of sincalide 0.01 microgram/kg/h over 2-24 h (mean, 8 h) for 1-12 days (mean, 5 days), usually until all evidence of ileus had resolved. Improvement was noted within 48 h of initiation of therapy in eight patients (75%), whereas marginal or no responses were observed in four patients. The mean duration of ileus was 3.6 days in responders and 7.7 days in nonresponders. Toxicity was minimal and consisted of diarrhea in two patients, in whom symptoms promptly resolved with discontinuation of the drug. Further explorations of this promising agent in the treatment of vincristine-induced ileus appears warranted.

Sensitivity of single- vs. double-contrast radiology in erosive gastritis

Radiologic sensitivity was determined in 54 patients with endoscopically diagnosed erosive gastritis. Four (24%) of 17 cases examined by single-contrast radiography and 16 (43%) of 37 cases examined by double-contrast radiography were detected. Double-contrast views and compression filming were both equally effective in diagnosing erosive gastritis during examinations where both were used. Although double-contrast examinations were more effective than single-contrast studies, both radiologic methods demonstrated poor sensitivity in detecting erosive gastritis.

Radiologic detection and spectrum of appearances of peptic esophageal strictures

We compared radiology and endoscopy in 80 patients with peptic esophageal stricture, with special attention to radiographic sensitivity for stricture caliber. Each stricture was classified by length into three types: 1) short (6-25 mm in length); 2) annular (under 6 mm in length); and 3) long (over 25 mm in length). Overall, radiology detected 95% of all strictures, including 90% of those over 1 cm in caliber. Morphologically, 75% of all strictures were short; 14% annular, and 11% long. Radiographically, smooth-stricture margins reliably excluded active esophagitis, while irregularity correlated well with its presence. Properly performed, barium esophagram can accurately detect esophageal strictures with a sensitivity approximating that of endoscopy.

Efficacy of radiology of the esophagus for evaluation of dysphagia

The efficacy of radiology in evaluating dysphagia was studied in 86 patients by comparison to endoscopic findings. In the 66 patients with endoscopic abnormalities radiology was correct in 54, for a sensitivity of 82%. Sensitivity of radiology improved to 95% if mild esophagitis was excluded. In the 20 patients with normal endoscopy, radiology was normal in 18 (90%). Thus radiology proved to be a reliable means of evaluating the esophagus in patients with dysphagia.

Reconstitution of acetylcholine receptor function using purified receptor protein

Membrane preparations containing only the four acetylcholine receptor polypeptide subunits (40, 50, 60, and 65 x 10(3) daltons) were purified from Torpedo californica electroplax. The receptor protein was extracted from these membranes with 2% aqueous sodium cholate, and complete dissolution into discrete molecular species was confirmed by sedimentation analysis. The solubilized preparation reassociated with exogenous phospholipids when the detergent was removed by dialysis and formed spherically sealed vesicles 400--600 A in diameter. The reconstituted receptor preparations had nearly 90% of their alpha-bungarotoxin binding sites exposed on the exterior surface of the vesicles. In a reproducible manner, the reconstituted acetylcholine receptor responded to carbamoylcholine by exhibiting a rapid efflux of 22Na+ from within the vesicles. Such preparations were successfully reconstituted only from acetylcholine receptor stabilized by asolectin above a minimal level upon dissolution of the original membrane preparation by detergent. In addition to the response to carbamoylcholine, the reconstituted preparations also exhibited pharmacological characteristics that resemble those observed for the original electroplax membranes. In terms of the carbamoylcholine-induced signal, a significantly large fraction of the total receptor was functionally reconstituted. The results also confirm the notion that only the four polypeptides considered to constitute the receptor are essential for acetylcholine-mediated cation translocation and rule out possible roles for other polypeptide species.

Quantitation of cation transport by reconstituted membrane vesicles containing purified acetylcholine receptor

A stopped-flow spectroscopic technique was used to study the kinetics of ion transport by reconstituted membrane preparations containing purified acetylcholine receptor. Influx of thallium (I) into membrane vesicles was monitored as a decrease, due to quenching by the thallous ion, in the fluorescence of an entrapped fluorophore. In a reproducible manner, the reconstituted receptor responded to cholinergic agonists by mediating rapid ion transport in the millisecond time range. The effect of agonists was blocked by receptor desensitization and by histrionicotoxin and was absent in membrane vesicles lacking receptor. Analysis of the fast kinetics of cation transport produced by saturating concentrations of agonists yielded an estimated rate of transport through a single reconstituted receptor channel. Comparison of this rate with those reported for in vivo preparations and for purified membranes shows that the reconstituted protein closely resembles the physiologically active receptor.

Reflux esophagitis revisited: prospective analysis of radiologic accuracy

A prospective radiologic-endoscopic study of the esophagogastric region in 266 patients, including 206 normals and 60 with esophagitis, is reported. The endoscopic classification grading severity of esophagitis was grade 1 -- normal; grades 2, 3, and 4 -- mild, moderate, and severe esophagitis, respectively. Radiology detected 22% of patients with mild esophagitis, 83% with moderate esophagitis, and 95% with severe esophagitis. Although hiatal hernia was present in 40% of normals and 89% with esophagitis, absence of radiographic hiatal hernia excluded esophagitis with 95% accuracy. The implications of this study regarding the role of radiology in evaluating patients with suspected reflux esophagitis are discussed.

Sensitivity of double-contrast barium enema: emphasis on polyp detection

Colonoscopically verified lesions (230 in 178 patients) were reviewed and compared to results of double-contrast barium enema studies performed by radiologists specifically interested in gastrointestinal disease. Eighteen carcinomas and 22 cases of colitis found endoscopically were accurately identified radiographically. In 140 patients with 190 polyps, 16 lesions were missed radiologically, a false-negative error for polyps of 8.4%. All undetected polyps were distal to the splenic flexure with the majority located in the sigmoid colon. Thus, the double-contrast barium enema study was quite effective in finding colon polyps, particularly proximal to the splenic flexure.

Transition form nonspecific motility disorder to achalasia

Achalasia is thought to be closely related to other motility disorders of the esophagus. In spite of this, transition between these disorders has rarely been documented. We present a patient who underwent a transition from a nonspecific motility disorder to achalasia. In addition there was return of peristalsis following a Heller myotomy.

Inflammatory fibroid polyp of the duodenum

Inflammatory fibroid polyp of the gastrointestinal tract is an unusual lesion of apparent submucosal origin but of unknown etiology. The stomach is most commonly involved with typical presentation being a rounded or oval polyp in the gastric antrum. Occurrence in the duodenum is distinctly rare since only three previous cases have been reported. We present a patient with an unusually long inflammatory fibroid polyp arising in the third portion of the duodenum.

Multiple esophageal webs

The case of a patient with numerous web-like constrictions involving the entire body of the esophagus is presented. The appearance is unlike any previously described for esophageal webs and rings. No known etiologic factors could be implicated and we have no speculations as to the cause.

Glucagon effects on the human small intestine

In healthy volunteers, the effects of intravenously administered glucagon on small intestinal function was investigated. Bolus doses resulting in plasma glucagon concentrations of greater than 800 pg/ml (5 min after injection) abolished jejunal contractions for 4.4 +/- 0.4 (SEM) min after a latency period of 49 +/- 4 sec. During continuous intravenous glucagon infusion, jejunal dilatation and increase in mean transit time (MTT) occurred at plasma levels greater than 720 pg/ml, while inhibition of water and electrolyte absorption was observed only with plasma glucagon concentrations of 1760 +/- 114 pg/ml. Under these conditions, the propulsion of fasting intestinal contents was slowed without change in flow rate. The observed effects cannot be attributed to the simultaneously occurring rise in plasma insulin and glucose concentrations. Short-term increases in circulating glucagon concentration inhibit intestinal tone, contractions, and propulsion with only a minor effect on water and electrolyte absorption limited to a narrow concentration range of plasma glucagon. Neither effect occurs at glucagon levels likely to occur under physiologic concentrations. The latency period preceding the abolition of jejunal contractions suggests that glucagon does not act directly on intestinal smooth muscle cells.

Secondary achalasia in esophagogastric carcinoma:re-emphasis of a difficult differential problem

Six cases of esophagogastric junction carcinoma are reviewed, with emphasis placed on differential diagnosis between achalasia and carcinoma. All six had abnormal motility with aperistalsis being the most common finding. Three patients demonstrated tapering of the distal esophagus simulating achalasia. Patients over 40 with recent onset of esophageal symptoms and radiographic signs suggesting achalasia should be suspected of harboring carcinoma.

Studies of the composition of purified Torpedo californica acetylcholine receptor and of its subunits

Under conditions that limit proteolytic degradation, the detergent-solubilized purified receptor protein from Torpedo californica exists in monomeric and dimeric forms. The purified receptor complex is composed of four different polypeptide subunits of apparent molecular weights 40 000, 50 000, 60 000, and 65 000. The individual polypeptides have been purified and their amino acid compositions have shown them to be relatively hydrophobic. In addition, the carbohydrate composition of the intact receptor complex and of the individual polypeptides has been determined. Amino acid analysis provided evidence for the occurrence of a component with chromatographic properties similar to those of phosphoserine. Treatment of receptor with CH3NH2 in base, a condition which provided quantitative modification of O-phosphoserine residues in beta-casein, completely eliminated the peak corresponding to phosphoserine following mild acid hydrolysis. We conclude that the receptor contains O-phosphoserine residues to the extent of approximately seven residues per molecule and these residues occur in all constituent polypeptides. Other forms of O-substituted serine and threonine were also shown to occur, most likely as glycosylated residues.

Reflux esophagitis: radiographic and endoscopic correlation

Although the value of endoscopy in reflux esophagitis is accepted, the role of radiology has not been well defined. The radiographic and endoscopic findings in 75 patients were correlated. A grading system was employed to stage the severity of involvement. Thirty-five appeared normal on endoscopy and 40 had esophagitis of differing stages of severity. The results indicate that radiography is insensitive in mild degrees of inflammation but that its sensitivity and accuracy improves in more severe grades of esophagitis.

The extent of successful colonscopy: its implication for the radiologist

Records of 230 colonoscopies were reviewed to determine the success in viewing the entire colon and the extent of the colon viewed when colonoscopy was incomplete. It was found that colonoscopy was complete to the cecum or ileum in 57% of studies, and that an average 63.8% of the colon was viewed during incomplete studies. Overall, 84.4% of the combined length of all colons examined was successfully viewed. The significant numbers of incomplete colonoscopies suggest that colonoscopy and the barium enema examination must remain complementary for maximum detection of colon lesions.

Transfer of episome F'lac+ and chromosomal trp+ genes from Erwinia amylovora to Salmonella typhimurium

The F'lac+ episome of Escherichia coli origin was transferred by conjugation with frequencies of 10(-7) to 10(-5) from Erwinia amylovora to 14 out of 15 Salmonella typhimurium trp female parents. The chromosomal trp+ genes were transferred with frequencies of 10(-7) to 10(-6) only to one trpB and 2 trpD female parents, which have a point mutation in the 2nd and fourth structural genes, respectively, of the tryptophan operon. The transferred male trp+ genes became integrated at the selected sites of the S. tryphimurium chromosome. The resulting Trp+ hybrids were phenotypically stable, lacked a cryptic trp allele selected against in the female parent, had high genetic homology values in the tryptophan region, and showed biochemical reactions and pathogenicity typical of S. typhimurium.

Lower esophageal sphincter responses to enteric hormones in two patients with Zollinger-Ellison syndrome

The effect of exogenous glucagon and secretin on resting lower esophageal sphincter (LES) tone during endogenous hypergastrinemia was studied in 2 patients with proven Zollinger-Ellison Syndrome (ZES). Intravenous glucagon and in one patient secretin, in dosages which decrease LES pressure in normals during LES stimulation by exogenous gastrin, caused a decrease in resting LES pressure in the ZES patients. This drop in LES tone occurred both during concomitant serum gastrin rise caused by secretin and serum gastrin decline caused by glucagon. This finding suggests that the action of secretin on LES pressure may be independent on endogenous gastrin, while the glucagon effect on LES tone may be mediated through gastrin.

Major complications of coloscopy: bleeding and perforation

The overall frequency and types of complications associated with diagnostic coloscopy and coloscopic polypectomy are unknown. A statewide survey of coloscopists was conducted to determine the morbidity and mortality associated with coloscopy. Twenty-eight physicians performed a total of 1,106 coloscopic procedures. 9 colonic perforations and 5 episodes of colonic bleeding resulted in a 1.3% complication rate. Explanations for several of the complications are identified and preventive measures proposed. 1 patient died of an unrecognized perforation of the sigmoid colon, resulting in a 0.09% mortality rate. Of 14 complications reported in this series, 12 occurred during the early experience (less that 40 procedures) of the coloscopist. Training programs in coloscopy need to be established in order to reduce the morbidity and mortality associated with a physician's early coloscopic experience.