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Biomedical subjects

A Wald

Publications and source records attributed to A Wald.

At least 145 records · Page 8Linked to original sources
PubMed1984

Computer analysis of radionuclide esophageal transit studies.

For detailed examination of the esophageal transit of a swallowed radioactive liquid bolus, three computer-based techniques have been developed: (a) analysis of time-activity curves with decomposition into rapid and residual components, yielding the mean transit time for the former and the residual fraction for the latter; (b) reduction of dynamic image sequences to single condensed images, facilitating subjective assessment; and (c) tracking of the centroid of radioactivity, permitting quantification of retrograde motion. Studies were performed on 12 normal subjects and on six patients with motility disorders. Elevated residual fractions were observed in all the patients, and an abnormal degree of retrograde motion in two. Two normal and two abnormal studies exemplify the variety of patterns observed in condensed images.

Adult↗
PubMed1983

Inappropriate use of cimetidine in hospitalized patients.

We reviewed the records of 100 medical and surgical patients who received cimetidine while hospitalized. Cimetidine use was categorized by FDA criteria as justified (23%), acceptable (40%), or unjustified (37%); prescribing patterns were similar in medical and surgical patients. Furthermore, intravenous cimetidine was often given when patients were receiving oral feedings, which resulted in unnecessary increases in hospital costs.

Administration, Oral↗
PubMed1983

Pregnancy-related changes in small intestinal myoelectric activity in the rat.

To determine if changes in intestinal motility occur during pregnancy, we studied small intestinal myoelectric activity, using monopolar electrodes, in fasted pregnant rats from day 12 to day 18 of the 22-day gestation period. We also studied fasting myoelectric activity in postpartum, nonpregnant, and castrate females. In all rats, the interdigestive myoelectric complex was invariably present with recurring activity fronts appearing at the proximal electrode and moving slowly abroad. Intervals between fronts were similar in all four groups, ranging from 12.61 min to 14.58 min. In pregnant rats, however, there was loss of the periodicity characteristic of activity fronts in the other groups; intervals up to 43 min in length were occasionally noted. Unorganized, randomly occurring spike potentials characterized these intervals. The average coefficient of variation of interval length was significantly (p less than 0.05) greater in pregnant rats (0.401) than in castrate (0.197) and nonpregnant rats (0.248). These studies confirm the presence in rats of pregnancy-related changes in small intestinal myoelectric activity.

Animals↗
PubMed1983

Biofeedback for neurogenic fecal incontinence: rectal sensation is a determinant of outcome.

Fifteen subjects (ages 5-33 years) with meningomyelocele and fecal incontinence underwent anorectal manometry followed by biofeedback conditioning of the external anal sphincter or nearby gluteal muscles. Seven of the 15 subjects undergoing biofeedback had improvement, defined as a 75% or greater decrease in the frequency of soiling, with a mean follow-up period of 23.1 months (range, 8-30 months). The seven subjects who improved with biofeedback had significantly lower thresholds of rectal sensation (smallest volume of distension perceived) than did the eight nonresponders; all responders had a sensory threshold less than or equal to 20 ml, whereas five of eight nonresponders had thresholds exceeding this level. Twenty-one children (ages 4-17 years) also underwent anorectal manometry, but not biofeedback conditioning, in order to evaluate the relationship of rectal sensation and peripheral neurological deficits. Fifteen of the 36 subjects with meningomyelocele had absent rectal sensation or thresholds exceeding 20 ml; there was no correlation of anorectal manometric parameters and peripheral sensorimotor levels. Response to biofeedback by children with meningomyelocele strongly correlates with rectal sensory thresholds which do not correlate with peripheral sensorimotor levels. If children with meningomyelocele and fecal incontinence are motivated and have adequate strength and coordination of the muscles of the lower extremities, anorectal manometry is the most accurate test to identify those who may benefit from biofeedback conditioning.

Adolescent↗
PubMed1982

Effect of pregnancy on gastrointestinal transit.

In order to evaluate the possible effects of pregnancy-associated sex steroids on gastrointestinal function, we determined gastrointestinal transit times and sex steroid levels in 15 women during the third trimester of their pregnancies and again 4--6 weeks following delivery when gastrointestinal function had symptomatically returned to normal. Gastrointestinal transit time from ingestion of a liquid lactulose meal to its delivery to the cecum was determined by monitoring breath hydrogen concentrations at 10-min intervals. Gastrointestinal transit times were significantly prolonged in the third trimester of pregnancy, when progesterone and estradiol levels were increased, compared to the postpartum period. This study supports previous findings which suggest that increasing levels of progesterone and estradiol affect gastrointestinal function and therefore may contribute to gastrointestinal symptoms that often occur in pregnant women.

Adult↗
PubMed1982

Hepatic angiosarcoma associated with short-term arsenic ingestion.

In a 45 year old man, hepatic angiosarcoma developed 33 years after medicinal arsenic ingestion of only six months' duration. In addition, the patient had a history of basal cell carcinomas without having had excessive sunlight exposure. Factor VIII staining of the tumor supports an endothelial cell origin of the tumor. The development of skin cancers and hepatic angiosarcoma in this patient suggests that there may be no safe threshold of arsenic exposure. A careful history concerning even short-term arsenic exposure in all patients with hepatic angiosarcoma may uncover more examples of this association.

Arsenic↗
PubMed1982

Lactose malabsorption in recurrent abdominal pain of childhood.

In order to evaluate the role of lactose malabsorption in children with recurrent abdominal pain, we performed a prospective controlled double-blinded study in 40 children with RAP of at least three months' duration. Children were studied for lactose malabsorption by breath hydrogen determinations after ingestion of lactose (2 gm/kg of body weight; maximum 50 gm). Lactose malabsorbers were retested with 12.5 gm lactose; lactose absorbers were retested with lactose for ability to produce hydrogen. All children underwent a dietary trial which included two lactose elimination periods. Although 12 children (30%) were lactose malabsorbers, only three malabsorbed part of the smaller, more physiologic, lactose load. Improvement rates of lactose malabsorbers and absorbers during lactose elimination were not significantly different as judged by their physicians and as determined by a 50% or more decrease in pain frequency. These results suggest that lactose malabsorption is of little importance in children with RAP.

Abdomen↗
PubMed1982

Stimulation of gastric acid secreted by glycine and related oligopeptides in humans.

To investigate the effect of oligopeptides on gastric secretion in humans, we investigated acid secretion in healthy volunteers after the intragastric infusion of physiological saline, glycine (100 mM), diglycine (50 mM), triglycine (33 mM), and tetraglycine (25 mM). All test solutions were equivalent in glycine content, osmolality (300 mosmol), and pH (5.5). Although the rate of acid secretion was greater during glycine than saline infusion [5.6 +/- 0.8 vs. 3.3 +/- 1.1 mmol/h (means +/- SE); P less than 0.05], the rate of acid secretion during glycine infusion was not significantly different from that induced by its related peptides. There were increases in plasma glycine concentration during infusion of glycine and its related peptides but no detectable changes in serum gastrin levels. The increases in plasma glycine must have been due to absorption from the small intestine because there was no gastric absorption of glycine in free or dipeptide form nor diglycine hydrolysis in the stomach. Therefore, our results permit implicating only the increased plasma glycine concentrations as the stimulus for acid secretion by glycine and its homologous peptides.

Adult↗
PubMed1981

Evidence refuting a role for increased abdominal pressure in the pathogenesis of the heartburn associated with pregnancy.

As a model of pseudopregnancy, the lower esophageal sphincter pressure and plasma gastrin and basal gastric pH levels were determined before and after diuresis in 10 men with tense ascites due to cirrhosis of the liver. Prior to diuresis, when abdominal pressure was increased, sphincter pressure was increased. After diuresis, when ascites was no longer a clinical problem, sphincter pressure was normal. None of the men had heartburn or demonstrable acid reflux either before or after diuresis. In addition, no differences in basal fasting levels of gastrin or gastric pH were noticed before and after diuresis. This study refutes a role for increased abdominal pressure due to an enlarging uterus in the pathogenesis of the heartburn of pregnancy. Moreover, it is consistent with those studies which suggest that increasing progesterone levels seen during pregnancy induce a loss of basal lower esophageal sphincter pressure and thereby allow the occurrence of acid reflux which produces symptomatic heartburn.

Abdomen↗
PubMed1981

Amyloidosis and chronic intestinal pseudoobstruction.

A 39-year-old woman with multiple myeloma developed chronic intestinal pseudoobstruction associated with gastrointestinal amyloidosis. Motor abnormalities of the lower esophageal and anal sphincters correlated closely with amyloid infiltration in affected areas. Manometric abnormalities of esophageal and anal sphincter function may provide indirect evidence of amyloid deposition of gastrointestinal smooth muscle in an appropriate clinical setting.

Adult↗
PubMed1981

Biofeedback therapy for fecal incontinence.

Twenty-five patients (ages 10 to 79 years; average, 48 years) with fecal incontinence underwent anorectal manometry with a three-balloon system connected to a physiograph. On a basis of manometric criteria showing the presence of rectal sensation, 17 patients underwent biofeedback conditioning. Underlying disorders included irritable bowel syndrome, diabetes mellitus, anal sphincter damage from surgery or disease, and neurogenic anal dysfunction. Twelve of the 17 patients who received biofeedback training had significant improvement in bowel soiling. Follow-up periods ranged from 2 to 38 months (mean, 15 months). There were no significant differences in threshold of rectal sensation, relaxation of the internal anal sphincter, and pre- and postbiofeedback thresholds of external anal sphincter contraction between responders and nonresponders. Minimal criteria for successful treatment appeared to be ability to sense rectal distension, good motivation, and absence of significant psychological dysfunction. Biofeedback conditioning is a simple and effective technique in the treatment of selected patients with fecal incontinence.

Adolescent↗
PubMed1981

Gastrointestinal transit: the effect of the menstrual cycle.

Gastrointestinal transit time as well as serum estradiol and progesterone levels were measured in 15 normally menstruating women twice during their menstrual cycle, once in the follicular phase (days 8-10) when progesterone levels are low and once in the luteal phase (days 18-20) when progesterone levels are increased. Each subject had a progesterone rise during the luteal phase and onset of menses at the expected time documenting ovulatory cycles. Gastrointestinal transit time from ingestion of lactulose to the delivery of the disaccharide to the cecum was determined by monitoring breath hydrogen levels at 10-min intervals. Gastrointestinal transit time was significantly (p less than 0.01) prolonged in the luteal phase when progesterone levels were increased compared with the follicular phase. This study demonstrates that the menstrual cycle plays an important role in determining the gastrointestinal transit time in normally menstruating women.

Adult↗
PubMed1981

Use of biofeedback in treatment of fecal incontinence in patients with meningomyelocele.

Fourteen children (aged 5 to 17 years) with meningomyelocele and significant fecal soiling underwent anorectal manometry using a three-balloon system connected to a physiograph. On the basis of manometric criteria demonstrating some rectal sensation, eight patients were treated with biofeedback conditioning. Patients were taught to contract the external and sphincter or nearby gluteal muscles in response to various volumes of rectal distention. Four of the eight patients who were treated with biofeedback had a good clinical response with disappearance of soiling or a greater than 75% improvement in the frequency of soiling. Follow-up periods ranged from three to 12 months. The minimum criteria for successful treatment appeared to be normal threshold of rectal sensation and ability to contract gluteal or related muscles. Anorectal manometry is a rapid, easily obtained test that can identify those children with meningomyelocele and fecal incontinence who may benefit from biofeedback conditioning. Biofeedback is a simple, safe, and effective technique in the treatment of certain children with fecal soiling due to neurogenic anal sphincter dysfunction.

Adolescent↗