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Biomedical subjects

H J McClung

Publications and source records attributed to H J McClung.

At least 19 recordsLinked to original sources
PubMed1998

The Internet as a source for current patient information.

OBJECTIVE: The purpose of this study was to assess the quality of information a lay person could obtain from Internet (Net) sources regarding the treatment of childhood diarrhea. It also afforded an opportunity to evaluate the awareness and compliance of the general medical community with the American Academy of Pediatrics (AAP) guidelines on the management of acute diarrhea. METHODS: This was a prospective, open, observational, literature review performed with a computer workstation and medical library. The AAP practice parameter on the management of acute gastroenteritis in young children was selected as the current standard by which to judge all other documents. The Net was searched, and all documents retrievable from the first 300 references were evaluated for compliance with current recommendations on the management of diarrhea in children. RESULTS: Of 60 articles published by traditional medical sources, only 12 (20%) conformed to current AAP recommendations for treatment of children. The source of the information, even if from a major academic medical center, did not improve the likelihood of compliance. CONCLUSIONS: As demonstrated by information supplied on World Wide Web sites by traditional medical sources, recommendations for the treatment of acute diarrhea show a low percentage of concurrence with the AAP guidelines. Major medical institutions, schools, and hospitals need to devise ways to carefully monitor and establish quality control of what is being distributed from their home pages. Patients must be warned about the voluminous misinformation available on medical subjects on the Net.

Acute Disease↗
PubMed1996

Galactose-containing carbohydrates are preferentially absorbed in the neonatal pig colon.

Previous studies on the piglet colon in newborns cleared of bacterial metabolic activity showed a capacity for lactose absorption. Colonic absorption occurred at a flux rate equal to the assimilation of lactose by the small intestine but by a process that did not involve either glucose-galactose sodium cotransport or simple diffusion. Surprisingly, colonic lactose transport did not require either fermentation or cleavage of the disaccharide for uptake. Experiments were designed to test the selectivity of the colonic transport process for a variety of carbohydrates. Colonic tissues from 4-7-d-old piglets were mounted in Ussing chambers and the mucosal-to-serosal flux of radiolabeled carbohydrates was compared with that of lactose. The results showed a 3-4-fold greater flux of galactose-containing sugars as compared with glucose-containing carbohydrates at concentrations up to 40 mM. Even lactulose, a synthetic disaccharide assumed to require bacterial digestion before assimilation, was transported readily. N-Acetylgalactosamine, a component of colonic mucus, inhibited the flux of lactose, whereas N-acetylglucosamine did not. Similarly, lactosylated BSA inhibited lactose flux, whereas nonlactosylated BSA did not. The capacity of the colon of the newborn to differentiate moieties as similar as glucose and galactose suggests an absorptive process for carbohydrates with a high degree of discrimination.

Animals↗
PubMed1996

Differentiating cyclic from chronic vomiting patterns in children: quantitative criteria and diagnostic implications.

OBJECTIVE: To establish criteria to differentiate two patterns of vomiting and to identify the predominant diagnoses for each group. METHODS: All children 2 to 18 years of age referred to a pediatric gastroenterology service who presented with recurrent vomiting (three episodes of vomiting within a 3-month period) as a primary complaint from 1985 to 1991 were retrospectively reviewed (n = 106). The vomiting pattern (emeses per hour and episodes per month), diagnostic studies, and therapeutic responses were compared by Mann-Whitney U and chi-squared tests. RESULTS: Based on the criteria of peak intensity (four or more emeses per hour) and frequency (nine or fewer episodes per month), two subgroups were differentiated: chilcren with a cyclic pattern (n = 34), who vomited at a higher peak intensity (12.6 +/- 1.6 vs 1.5 +/- 0.1 emeses per hour) but at a lower frequency (1.9 +/- 4.8 vs 36.6 +/-0.3 episodes per month) than those with a chronic pattern (n = 72). Among children with a cyclic patern, nongastrointestinal (65%) causes, especially peptic and infectiouus disorders, predominated over nongastrointestinal ones (10%). CONCLUSIONS: On the basis of quantitative historical criteria, children with recurrent vomiting can be classified into two subgroups that seem to be clinically and etiologically distinct. Abdominal migraine was the dominant diagnosis in those with cyclic vomiting, whereas peptic and infectious gastrointestinal disorders predominated in those with chronic vomiting. This differentiation between cyclic and chronic patterns of vomiting may be a useful diagnostic clue to the clinician.

Child↗
PubMed1995

Constipation and dietary fiber intake in children.

OBJECTIVE: Severe constipation in children is associated with rectal overdistension and insensitivity. Treatment typically involves three phases: disimpaction (days to weeks), laxative use (months), and a high-fiber diet (lifelong). The purpose of this survey is a discussion of therapies that recognize the unique problems that children with severe constipation have. METHODS: Four-day diet logs were obtained from children who had no history of chronic bowel disease. Their intake of dietary fiber was determined from the logs and was compared with the dietary fiber ingested by children who had chronic constipation. These data sets were compared in light of our current understanding of the need for dietary fiber. RESULTS: Approximately half of the children from families who were health conscious enough to request dietary evaluation still fell below the age + 5 guidelines for grams of dietary fiber intake per day. The children referred to use with chronic constipation had all been instructed "to eat a high-fiber diet." Those constipated patients were consuming less than one fourth of the recommended fiber intake. CONCLUSIONS: This survey underscored the difficulties in beginning and in maintaining high-fiber diets in children. When families receive advice to administer a high-fiber diet, they are unable to accomplish this unless they receive intensive and ongoing dietary counseling. Even among health-conscious families, only half of the children received the recommended amounts of dietary fiber. Further public education in this regard is warranted.

Cathartics↗
PubMed1994

Sedation with meperidine and midazolam in pediatric patients undergoing endoscopy.

We conducted a randomized, double-blind trial evaluating the efficacy and safety of meperidine 2 mg.kg-1 (M) and meperidine 2 mg.kg-1 plus midazolam 0.05 mg.kg-1 (M + M) in 40 pediatric outpatients (age 1 to 17 years) undergoing upper endoscopy procedures. The physician and nurse performing the procedure were asked to rate cooperation, emotional status, drowsiness, and overall efficacy. A blinded observer recorded the frequency of negative behaviors indicating distress, vital signs, and oxygen saturation before, during, and after the procedure. No significant differences were noted in the overall efficacy of the regimens. Good or excellent efficacy was noted in 15 of 21 children (71%) in the M group and 15 of 19 children (79%) in the M + M group by physicians; nurses assigned a good or excellent rating for 14 of 21 (67%) and 13 of 19 (68%) in the M and M + M groups, respectively. Immediately following the procedure, amnesia was noted in 4 of 17 (23%) patients who received M versus 14 of 18 (78%) patients who received M + M (P = 0.002). Of the children who received M + M, the amnesia tended to occur more frequently in older children (> 11 years, 8 children, rate of amnesia 100%) than in younger children (< or = 11 years, 6 of 10 evaluable children, rate of amnesia 60%). There was no significant difference between the frequency of negative behaviors, rate of adverse effects, or changes in vital signs or oxygen saturation noted with the two drug regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Efficacy of diazepam and meperidine in ambulatory pediatric patients undergoing endoscopy: a randomized, double-blind trial.

Medications are routinely administered to children prior to upper gastrointestinal endoscopy procedures. We evaluated the efficacy and safety of four dosage regimens: meperidine 2 mg/kg (M); low-dose meperidine 1 mg/kg and diazepam 0.1 mg/kg (M low+D); high-dose meperidine 2 mg/kg and diazepam 0.1 mg/kg (M high+D); and, diazepam 0.1 mg/kg (D) in a randomized, double-blind trial in 71 pediatric patients (ages 1 to 19 years). Cooperation, emotional state, and sedation were rated. The frequency of negative behavior demonstration (i.e., crying, gagging, flailing, nervous behavior) indicating ineffective or inadequate sedation was recorded before, during, and after the procedure. Vital signs and oxygen saturation were noted. Significant differences were observed in the efficacy of the various sedation regimens. Overall, the physicians and nurses rated M most effective in children < 11 years. In these children, M high + D and D were rated least effective by the nurses, whereas physicians felt that D was least effective. In the older children, M, M low + D, and M high + D were rated similarly effective by physicians and nurses, and D was rated least effective. In both age groups, the lowest incidence of negative behaviors during the endoscopy procedure occurred in patients who received M. Combinations of D and M + D resulted in an increased incidence of negative behaviors; thus, M may be the preferred sedation regimen in children undergoing endoscopy. The addition of diazepam to meperidine may be detrimental in terms of eliciting negative behaviors.

Adult↗
PubMed1993

Lactose flux occurs by differing mechanisms in the colon and jejunum of newborn piglets.

The unidirectional flux of 10- and 40-mM lactose was studied in newborn porcine jejunum and colon mounted in Ussing chambers. Polyethylene glycol 400 was used to measure passive paracellular permeability. The mucosal-to-serosal flux and the tissue accumulation of labeled lactose from the colon was similar to that of lactose-derived glucose from the jejunum. However, only jejunum showed a lactose-stimulated increase in short-circuit current. In jejunum, glucose was the sole sugar identified in the serosal bath, whereas in colon, only intact lactose was identified. Despite colonic lactose flux, polyethylene glycol oligomers were not found in the serosal bath, suggesting that they do not share the same route of absorption. Colonic lactose transport was nonsaturable between 1 and 40 mM. Under nongradient conditions, no net colonic lactose transport was observed. Cumulatively, these data suggest that the colon, unlike the jejunum, does not contain a glucose-galactose sodium cotransporter. The colon of the newborn piglet transports intact lactose at a flux equal to that of lactose-derived glucose by the small intestine, but by a different mechanism that is as yet undefined.

Animals↗
PubMed1993

Is combination therapy for encopresis nutritionally safe?

Chronic constipation accounts for 3% to 5% of pediatric primary care outpatient visits. The most severely affected of this group develop a flaccid colon insensitive to distention, and encopresis. Laxatives and lubricants have been the standard therapeutic agents during the bowel decompression phase of encopretic therapy. Fiber has been the cornerstone of maintenance programs. Each of these agents is accompanied by considerable anxiety in the lay literature. This study evaluates the safety of combined high-fiber, laxative, and lubricant therapy on bowel movement frequency, fecal soiling, and nutritional status over a 6-month period. Blood chemistry values, dietary fiber intake, defecation pattern, and psychological profile were evaluated before and after the 6-month study. Biochemical and anthropometric indicators of nutritional status were not adversely affected by the therapy. Seventy-five percent of the children were able to remain free of soiling and the remaining 4 of 16 had soiling episodes reduced to a frequency of less than once a week. This study confirms that children with encopresis can respond to a combined program of increased fiber intake, laxatives, and mineral oil following a complete bowel cleanout, without experiencing deleterious effects.

Cathartics↗
PubMed1992

Enterohepatic distribution of carnitine in developing piglets: relation to glucagon and insulin.

L-Carnitine plays a crucial role in the perinatal transition from carbohydrate to lipid-derived energy. To examine the potential contribution of assimilated dietary carnitine to the elevated hepatic concentrations in newborns, we measured carnitine concentrations in sow milk, jejunum, and liver, and in vitro jejunal carnitine transport in piglets aged 1-36 d. Hepatic and sow milk total carnitine concentrations peaked soon after birth and declined with age (p = 0.035 and 0.026, respectively). Although jejunal total carnitine concentrations remained stable, jejunal carnitine flux was higher at 2 d of age than in older piglets. To examine the possible signals that regulate hepatic carnitine, portal enteroinsular hormones were measured by RIA. Portal glucagon (p = 0.0006), insulin (p = 0.0001), and glucagon:insulin ratio (p = 0.037) were related to age. Portal glucagon was highest in newborns and during weaning, whereas insulin increased progressively with age; the portal glucagon:insulin ratio, like hepatic carnitine, peaked soon after birth and fell with age. A multiple regression analysis indicated a positive association between glucagon and hepatic carnitine and a negative one between insulin and hepatic carnitine (R = 0.802, p = 0.001). An overall pattern of elevated dietary carnitine levels and increased small intestinal absorption and hepatic accumulation of carnitine is noted in early development. The finding of a similar pattern in glucagon-to-insulin ratio suggests that both hormones may participate in the regulation of enterohepatic carnitine distribution in newborns.

Aging↗
PubMed1991

Recurrent pancreatitis in three patients with chronic idiopathic intestinal pseudo-obstruction.

Chronic idiopathic intestinal pseudo-obstruction is a syndrome with substantial morbidity and mortality associated both with the syndrome and with its therapy. Standard therapy has included prokinetic agents and intravenous nutritional support when oral feedings are inadequate to maintain nutriture. We report three children with chronic intestinal pseudo-obstruction who experienced one or more attacks of pancreatitis. Two patients developed pseudocysts. One patient died. All three patients underwent cholecystectomy; one had stones, one had acalculous cholecystitis, and one had a normal gallbladder. All patients received prokinetic agents and total parenteral nutrition as therapy for their pseudo-obstruction. Candidate mechanisms to explain the etiology for pancreatitis in chronic intestinal pseudo-obstruction include biliary dysmotility associated with pseudo-obstruction and excessive cholinergic stimulation due to therapy with prokinetic agents.

Child↗
PubMed1991

Absorption of lactose from colon of newborn piglet.

Piglets in three age groups (1-3, 9-11, and 16-25 days after birth) were used for in vivo colonic perfusions. Studies compared an isosmolar (312 mosM) with a high osmolar (551 mosM) solution and two equimolar substrates (with hexose concentrations of 73.1 mM), lactose and glucose-galactose. From the isosmolar perfusates, lactose absorption was 0.43 +/- 0.04 in the 18-20 day olds and 1.04 +/- 0.2 mumol.cm-1.min-1 in the 1-3 day olds; absorption from the glucose-galactose solution was negligible in all age groups (less than 0.05 +/- 0.05 mumol.cm-1.min-1). From the high osmolar perfusate, lactose absorption also exceeded that of glucose and galactose. In a third set of perfusion studies, the concentration of lactose was varied between 15 and 240 mM perfusate. Five-day-old animals absorbed 67% more lactose than 18-day-old animals; the right colon absorbed 57% more than the left. Lactose absorption, correlated with its concentration in the perfusate (r = 0.99), was nonsaturable at concentrations up to 240 mM, and was correlated with the uptake both of sodium (r2 = 0.59 for young and 0.64 for older neonates) and of chloride (r2 = 0.55 for young and 0.31 for older neonates). The results suggest that lactose may be removed from the colon without apparent cleavage by beta-galactosidase.

Animals↗
PubMed1991

Glucose flux from dietary disaccharides: all sugars are not absorbed at equal rates.

Considerable discrepancies exist in the literature regarding the rates of glucose absorption from the common dietary disaccharides, lactose, maltose, and sucrose. This study compared the unidirectional flux of glucose derived from dietary disaccharides with that of their constituent monosaccharides in vitro. Lactose-stimulated short-circuit current (Isc) and mucosal-to-serosal flux (Jm----s) were lower than that of an equimolar glucose-galactose mixture and were phlorizin inhibitable. Maltose- and glucose-stimulated Isc were similar, but Jm----s of glucose derived from the hydrolysis of maltose was lower than that of free glucose. Sucrose-stimulated Isc and Jm----s were similar to that of an equimolar glucose-fructose mixture. Isc and Jm----s of glucose from both maltose and sucrose were phlorizin and acarbose inhibitable. We conclude that the rate of glucose uptake from disaccharides is less than or equal to that of free glucose and is dependent on the glucose source. We speculate that regulation of glucose uptake from disaccharides can occur at three sites: the hydrolytic enzyme, the glucose transporter, and the tight junctions.

Absorption↗
PubMed1990

Failure to conserve lactose and glucose polymers during frozen storage of fecal specimens: methods for preservation.

Freezing is often used to retard bacterial enzymatic activity in fecal specimens collected to quantify specific carbohydrates. The effectiveness of freezer storage on preservation of lactose and glucose polymers was assessed. The data showed that more than 50% of lactose that was added to fecal supernatants that were stored without treatment for more than 50 days at -20 degrees C was lost. Adjustment of pH with HCl (pH 4.9), with HgCl2 (pH 6.3 or 5.85), or with NaOH (pH 10) improved carbohydrate preservation (P less than 0.0004). Storage of the supernatants of fecal homogenates lessened the loss of carbohydrate compared with the total homogenates (P less than 0.001). In supernatants, degradation occurred via simple hydrolysis; in homogenates, degradation occurred by hydrolysis and fermentation to a variety of end-products. Unprocessed fecal specimens that were frozen for months, then retrieved and incubated with lactose or glucose polymers showed extensive fermentative capacity. Cumulatively, the data indicate that enzymatic activity in feces is not halted by storage in the freezer, even if bacteria have been filtered from the stool.

Animals↗
PubMed1990

Efficacy and safety of a diazepam and meperidine combination for pediatric gastrointestinal procedures.

Little has been published about outpatient sedation for pediatric patients. We designed a study to evaluate the efficacy and adverse effects of diazepam and meperidine in combination for sedation in ambulatory pediatric patients undergoing endoscopy, colonoscopy, or liver biopsy. Thirty patients (7 months-20 years) were observed. Each patient received a single combined dose of intravenous diazepam and meperidine. The standard dose was 0.1 mg/kg for diazepam and 2.0 mg/kg for meperidine. In patients weighing greater than 100 lb, set doses of meperidine (100 mg) and diazepam (5 mg) were used. The time to achieve sedation and the vital signs were measured; cooperation, emotional state, and drowsiness were rated before, during, and after procedures. The amnesic effect was noted, as were any adverse effects. Diazepam and meperidine were effective in 26 of 30 patients, with sedation generally produced within 2-3 min. Cooperation and emotional state improved significantly following drug administration (p less than 0.05). When a prospective 24-h telephone follow-up study was instituted in 40 consecutive patients receiving diazepam and meperidine no significant adverse effects were noted. Only 20% of patients old enough to be questioned remembered the procedure. Diazepam and meperidine in combination appear to be effective and safe in pediatric patients undergoing gastrointestinal procedures. Prolonged monitoring of patients does not appear necessary in this patient population.

Adolescent↗