Efficacy, dose reduction, and resistance to high-dose fluticasone in patients with eosinophilic esophagitis

BACKGROUND & AIMS

We evaluated the efficacy and safety of high-dose swallowed fluticasone propionate (FP) and dose reduction in patients with eosinophilic esophagitis (EoE) and analyzed esophageal transcriptomes to identify mechanisms.

METHODS

We conducted a randomized, multisite, double-blind, placebo-controlled trial of daily 1760 mcg FP in participants age 3-30 years with active EoE. Twenty-eight participants received FP, and 14 participants received placebo. After 3 months, participants given FP who were in complete remission (CR) received 880 mcg FP daily, and participants in the FP or placebo groups who were not in CR continued or started, respectively, 1760 mcg FP daily for 3 additional months. The primary end point was histologic evidence for CR. Secondary end points were partial remission (PR), symptoms, compliance, esophageal gene expression, esophageal eosinophil count, and the relationship between clinical features and FP responsiveness.

RESULTS

After 3 months, 65% of subjects given FP and no subjects given placebo were in CR (P = .0001); 12% of those given FP and 8% of those given placebo were in PR. In the FP group, 73% of subjects remained in CR, and 20% were in PR after the daily dose was reduced by 50%. Extending FP therapy in FP-resistant participants did not induce remission. FP decreased heartburn severity (P = .041). Compliance, age, sex, atopic status, or anthropomorphic features were not associated with response to FP. Gene expression patterns in esophageal tissues of FP responders were similar to those of patients without EoE; there was evidence for heterogeneous steroid signaling in subjects who did not respond to FP and preliminary evidence for transcripts predictive of FP responsiveness.

CONCLUSIONS

Daily administration of a high dose of FP induces histologic remission in 65%-77% of patients with EoE after 3 months. A 50% dose reduction remained effective in 73%-93% of patients who initially responded to FP. Nonresponders had evidence of steroid resistance; histologic and molecular markers may predict resistance. Clinicaltrials.gov number: NCT00426283.

Foreign body impaction as presentation of eosinophilic esophagitis

Esophageal foreign body is a frequent pediatric presentation, and eosinophilic esophagitis (EoE) is an important underlying disease. To determine characteristics common in the presentation of esophageal foreign body indicative of underlying EoE and reach a recommendation for the appropriate scenario in which to obtain esophageal mucosal biopsy, 312 pediatric esophageal foreign bodies requiring operative removal were reviewed. Patients older than 18 years or with a known history of esophageal surgery or pathology were excluded. Eligibility criteria were met in 271 cases. Twenty-seven patients were biopsied, and 18 were diagnosed with EoE. The following factors were identified in the EoE population: food impaction (89%), older age (average 12.2 years), male sex (78%), atopic disease (61%), previous esophageal foreign body or frequent dysphagia (83%), and endoscopic abnormalities (100%). These factors are all associated with an underlying diagnosis of EoE, and patients meeting these criteria should be strongly considered for intraoperative esophageal mucosal biopsy.

Effect of decreased parenteral soybean lipid emulsion on hepatic function in infants at risk for parenteral nutrition-associated liver disease: a pilot study

PURPOSE

We performed a pilot trial to compare reduced dose versus standard soybean lipid emulsion in neonates at risk for parenteral nutrition-associated liver disease.

METHODS

A prospective randomized controlled trial was performed (2009-2011) enrolling surgical patients ≥ 26 weeks' gestation anticipated to require >50% of daily caloric intake from parenteral nutrition (PN) for at least 4 weeks. Randomization occurred into either reduced (1.0 g/kg/day) or standard (3g/kg/day) groups. Co-primary outcomes for interpretation of the results were conjugated bilirubin and total bile acids. Additional outcomes included ALT, AST, GGT, alkaline phosphatase, growth, and essential fatty acid levels. Outcomes were compared between treatment groups using Wilcoxon rank sums tests.

RESULTS

Twenty-eight patients (47% enrollment rate) were included in the study with an average treatment duration of 5.4 weeks. Groups had similar PN calories and protein intake throughout the study. Total increase from baseline was smaller in the reduced vs. standard group for conjugated bilirubin (p=0.04) and total bile acids (p=0.02). Weight z-score increased more in the standard group, and no patient experienced essential fatty acid deficiency.

CONCLUSION

Markers of cholestasis rose at a slower rate using reduced lipid doses. This pilot study demonstrates feasibility and need for a larger study evaluating the effects of reduced lipids in patients at risk for developing parenteral nutrition-associated liver disease.

Foreign Body as Initial Symptom of Eosinophilic Esophagitis

Objective: 1) Determine characteristics common in the presentation of esophageal foreign body that indicate presence of underlying esophageal pathology. 2) Provide clinical guidelines to consider esophageal mucosal biopsy during foreign body removal.

Method: Three hundred twelve cases of pediatric patients with an esophageal foreign body requiring esophagoscopy for removal were reviewed. Patients were excluded if a history of esophageal surgery or pathology was present. Factors common to those patients subsequently diagnosed with eosinophilic esophagitis (EE) were identified.

Results: Eligibility criteria were met in 271 cases. Of these, 27 underwent esophageal biopsy and 18 were diagnosed with EE. The following factors were compared between the EE population and the group as a whole: food impaction (89% of EE patients, 11% of non-EE patients), older age (average EE age 11.9, overall average age 4.5), atopic disease (61.1% of EE, 17.0% non-EE), abnormalities on esophagoscopy (94.4% of EE, 8.9% overall), and previous esophageal foreign body or frequent dysphagia (83.3% of EE, 5.9% non-EE). Eighteen percent of EE patients had 2 or more impactions requiring esophagoscopy prior to a biopsy being taken.

Conclusion: Older age, food impaction, history of atopic disease or previous esophageal foreign body, and abnormalities on esophagoscopy are all associated with EE. Patients meeting these criteria should be strongly considered for mucosal biopsy during foreign body removal. Failure to do so may lead to repeated foreign body events.

Adverse outcomes associated with gastroesophageal reflux disease are rare following an apparent life-threatening event

OBJECTIVE

To evaluate for adverse outcomes associated with gastroesophageal reflux disease (GERD) following an apparent life-threatening event (ALTE) and potential risk factors of these outcomes.

STUDY DESIGN

Retrospective cohort study of well-appearing infants (<12 months) admitted for ALTE. Patients were followed for adverse outcomes associated with GERD (including aspiration pneumonia, failure-to-thrive, or anti-reflux surgery), second ALTE, or death. Risk factors evaluated included: age, prematurity, gender, previous event, diagnosis of GERD, gastrointestinal (GI) testing positive for gastroesophageal reflux, length of stay (LOS), and neurologic impairment diagnosed in follow-up.

RESULTS

Four hundred sixty-nine patients met inclusion criteria, mean age was 45 days, 110 (22%) were premature. Patients were followed for an average of 7.8 years; 3.8% of all patients had an adverse outcome associated with GERD. The only significant risk factors were a longer LOS, and development of neurological impairment. A diagnosis of GERD and positive reflux testing during the initial hospitalization were not associated with adverse outcomes associated with GERD.

CONCLUSIONS

Adverse outcomes associated with GERD are rare following an ALTE. Patients who developed neurological impairment and a longer initial LOS were at higher risk for developing these outcomes. Positive testing for gastroesophageal reflux during hospitalization for ALTE did not predict adverse outcomes associated with GERD.

Clinical variables as prognostic tools in pediatric-onset ulcerative colitis: a retrospective cohort study

BACKGROUND

Clinical variables may identify a subset of patients with pediatric-onset ulcerative colitis (UC) (≤18 years at diagnosis) at risk for adverse outcomes. We postulated that routinely measured clinical variables measured at diagnosis would predict colectomy in patients with pediatric-onset UC.

METHODS

We conducted a chart review of patients with pediatric-onset UC at a single center over a 10-year period. We compared patients with and without colectomy across several variables, used proportional hazards regression to adjust for potential confounders, and assessed the ability of a UC risk score to predict colectomy.

RESULTS

Among 470 patients with inflammatory bowel disease ICD9-coded encounters, 155 patients had UC and 135 were eligible for analysis. The 1- and 3-year colectomy rates were 16.7% (95% confidence interval [CI]: 11.0%-24.8%) and 35.6% (26.7%-45.4%). White blood cell (WBC) count and hematocrit measured at diagnosis were associated with colectomy at 3 years, even after correcting for potential confounding variables. A UC Risk Score derived from the WBC count and hematocrit was strongly associated with colectomy risk, with a high negative predictive value (NPV) for colectomy at 1 and 3 years (NPV = 0.95 and 0.89, respectively), but low positive predictive value (PPV = 0.22 and 0.38, respectively).

CONCLUSIONS

A risk score calculated from WBC and hematocrit measured at diagnosis was associated with, but incompletely predictive of, colectomy in pediatric-onset UC. These data suggest 1) routinely measured clinical variables may have a prognostic role in risk stratification, and 2) multicenter prospective studies are needed to optimize risk stratification in pediatric UC. Our findings have impact on the design of such studies.

Improving the prevention, early recognition, and treatment of pediatric obesity by primary care physicians

To determine if participation in a learning collaborative (LC) would improve care processes for prevention, early recognition, and treatment of childhood obesity by primary care physicians (PCP), the authors conducted pre-post evaluations of the use of obesity related care processes by 18 primary care practices following participation in a 9-month LC based on the Model for Improvement. Prior to the LC, chart audits revealed that 55% of patients had a BMI recorded; this rose to 97% of patients at its conclusion. Following the LC, 11 practices had implemented systematic prevention advice to parents of infants compared with 3 prior to the LC. All practices developed plans for evaluation and management of children with an elevated BMI. Participation in an LC increased the number of primary care practices that provided anticipatory guidance regarding obesity prevention and that identified and treated overweight or obese children.

Elimination of soybean lipid emulsion in parenteral nutrition and supplementation with enteral fish oil improve cholestasis in infants with short bowel syndrome

BACKGROUND

Parenteral nutrition-associated liver disease (PNALD) is a potentially fatal complication for children with intestinal failure. Fish oil-based lipid emulsions have shown promise for the treatment of PNALD but are not readily available. Six cases are presented in which cholestasis resolved after soybean lipid emulsion (SLE) was removed from parenteral nutrition (PN) and enteral fish oil was given.

METHODS

A retrospective review at a tertiary children's hospital (July 2003 to August 2008) identified 6 infants with intestinal failure requiring PN for >6 months who developed severe hepatic dysfunction that was managed by eliminating SLE and providing enteral fish oil.

RESULTS

Twenty-three infants with short bowel syndrome requiring prolonged PN developed cholestasis. SLE was removed in 6 of these patients, and 4 of the 6 received enteral fish oil. Standard PN included 2-3 g/kg/d SLE with total PN calories ranging from 57 to 81 kcal/kg/d at the time of SLE removal. Hyperbilirubinemia resolved after elimination of SLE within 1.8-5.4 months. Total PN calories required to maintain growth generally did not change.

CONCLUSIONS

Temporary elimination of SLE and supplementation with enteral fish oil improved cholestasis in PN-dependent infants. Further trials are needed to evaluate this management strategy.

Correlation of duodenal histology with tissue transglutaminase and endomysial antibody levels in pediatric celiac disease

BACKGROUND & AIMS

IgA antibodies against tissue transglutaminase (TTGA) and endomysium (EMA) are sensitive and specific markers for celiac disease (CD). Data correlating TTGA and EMA levels with degree of villous atrophy are limited. We compared duodenal histopathology in pediatric CD patients with TTGA and EMA serologies, symptoms, height, and weight.

METHODS

We identified 117 pediatric patients retrospectively who had serologic testing for IgA TTGA and IgA EMA and duodenal biopsies graded by modified Marsh criteria as 0-3c. Data were analyzed with Spearman rank correlation and multinomial logistic regression.

RESULTS

IgA TTGA (r = .704, P < .001) and IgA EMA (r = 0.740, P < .001) correlated with intestinal villous atrophy in pediatric CD patients by Spearman rank correlation. Similar correlations were found in a subset of 23 patients younger than 3 years of age. Multinomial logistic regression revealed increased probability of Marsh 3a or greater changes with increasing TTGA or EMA levels. Strongly positive antibody levels (TTGA >100 units or EMA titer >1:1280) were highly specific (>98%) for Marsh 3a or greater lesions. Among symptoms, abdominal distention and diarrhea were associated with abnormal histology.

CONCLUSIONS

IgA TTGA and EMA levels correlate with duodenal villous atrophy in pediatric CD patients. IgA TTGA >100 or EMA >1:1280 were nearly always associated with CD histopathology. With further validation of this observation, strongly positive titers might be considered sufficient for diagnosis of pediatric patients at risk for CD. Symptoms, height, and weight are not reliable predictors of CD.

Gastrointestinal polyposis in childhood: clinicopathologic and genetic features

Gastrointestinal polyps and certain extraintestinal lesions in children may herald a hereditary polyposis syndrome, with an increased risk of neoplasia and other health problems for both children and their relatives. The availability of molecular/genetic screening tests has increased early diagnosis of younger members of known polyposis families. This article reviews the gross and microscopic features of polyposis syndromes of childhood and summarizes the molecular/genetic advances in this field. Clinical management is also briefly discussed.

Prolongation of satiety after low versus moderately high glycemic index meals in obese adolescents

BACKGROUND

One in 5 American children is overweight, despite a decrease in total fat consumption. This has sparked an interest in the carbohydrate composition of diets, including the glycemic index (GI).

OBJECTIVE

To investigate whether a low-GI meal replacement (LMR) produced similar metabolic, hormonal, and satiety responses in overweight adolescents as a low-GI whole-food meal (LWM) when compared with a moderately high-GI meal replacement (HMR).

METHODS

Randomized, crossover study comparing LMR, HMR, and LWM in 16 (8 male/8 female) adolescents during 3 separate 24-hour admissions. The meal replacements consisted of a shake and a nutrition bar. Identical test meals were provided at breakfast and lunch. Metabolic and hormonal indices were assessed between meals. Measures of participants' perceived satiety included hunger scales and ad libitum food intake.

RESULTS

The incremental areas under the curve for glucose were 46% and 43% lower after the LMR and LWM, respectively, compared with the HMR. Insulin's incremental area under the curve was also significantly lower after both low GI test meals (LMR = 36%; LWM = 51%) compared with the HMR. Additional food was requested earlier after the HMR than the LMR (3.1 vs 3.9 hours, respectively), although voluntary energy intake did not differ.

CONCLUSIONS

Differences in insulin response between the meal replacements occurred, and prolongation of satiety after the LMR, based on time to request additional food, was observed. We speculate that the prolonged satiety associated with low GI foods may prove an effective method for reducing caloric intake and achieving long-term weight control.

High-dose steroids, ursodeoxycholic acid, and chronic intravenous antibiotics improve bile flow after Kasai procedure in infants with biliary atresia

BACKGROUND/PURPOSE

Early reports suggest that the use of steroids after Kasai portoenterostomy may improve bile flow and outcome in infants with biliary atresia.

METHODS

Of 28 infants with biliary atresia, half received adjuvant high-dose steroids, and half received standard therapy. Infants in the steroid group (n = 14) received intravenous solumedrol (taper of 10, 8, 6, 5, 4, 3, 2 mg/kg/d), followed by 8 to 12 weeks of prednisone (2 mg/kg/d). The steroid protocol also included ursodeoxycholic acid indefinitely and intravenous antibiotics for 8 to 12 weeks followed by oral antibiotic prophylaxis. Infants in the standard therapy group (n = 14) received no steroids, occasional ursodeoxycholic acid, and perioperative intravenous antibiotics followed by oral antibiotic prophylaxis. The infants were not assigned randomly, but rather received standard therapy or adjuvant steroid therapy according to individual surgeon preference.

RESULTS

Eleven of 14 (79%) in the steroid group and 3 of 14 (21%) in the standard therapy group had a conjugated bilirubin level less than 1.0 within 3 to 4 months of surgery (P <.001). Fewer patients in the steroid group (21% v 85%) required liver transplantation or died during the first year of life (P <.001). Infants in the steroid group did better despite the fact that this group included 5 infants with biliary atresia-polysplenia-heterotaxia syndrome, a subgroup that might have been expected to have a poor prognosis. Neither bile duct size nor liver histology was a reliable predictor of success or failure in either group.

CONCLUSIONS

Adjuvant therapy using high-dose steroids, ursodeoxycholic acid, and intravenous antibiotics may accelerate the clearance of jaundice and decrease the need for early liver transplantation after Kasai portoenterostomy.

Antioxidant status of young children: response to an antioxidant supplement

OBJECTIVE

To study oxidative stress indicators in healthy young children and their response to a commercially available fruit- and vegetable-based antioxidant supplement.

DESIGN

Healthy children were randomly assigned to a placebo and a supplement (commercial antioxidant supplement produced from dried fruit and vegetable extracts and fortified with antioxidants, resembling a gummy-type candy). The placebo and the supplement were taken in 2 doses per day for 21 days.

SUBJECTS

Participants were 39 children (26 boys and 13 girls) aged 5 to 10 years. Research was conducted at Primary Children's Medical Center and the University of Utah, Salt Lake City.

MAIN OUTCOME MEASURES

Breath and urine samples were collected on days 1 and 21 and assayed for breath pentane and urine 8-hydroxydeoxyguanosine, malondialdehyde, nitrites, and 8-isoprostane as noninvasive indicators of oxidative stress. Urine oxygen radical absorbance capacity was measured at days 1 and 21 as an indirect indicator of the antioxidant capacity of the body. Three-day food records were collected at the beginning and end of the study to measure intake of dietary fruit; vegetable; and antioxidant vitamins A, C, and E.

STATISTICAL ANALYSIS

Descriptive statistics, repeated measures analysis of variance, paired t tests, and Pearson r correlations.

RESULTS

Markers of oxidative stress were not significantly different between the placebo and supplement groups at day 1 or day 21. The oxidative stress indicators of the healthy children in this study appear to be similar to those of healthy adults and were not changed by antioxidant supplementation. The diet record analyses indicated that mean fruit and vegetable intakes (2.75 servings/day) were similar to the national average intake for children in the United States.

APPLICATIONS/CONCLUSIONS

This research presents original information on the subject of oxidative stress in healthy children. The results of this study may be useful as reference baseline markers to use in conjunction with clinical dietary evaluations and for future research with healthy children and with children in disease states who are subject to elevated levels of oxidative stress.

Pancreatitis: etiology, diagnosis, and management

Inflammation of the pancreas (pancreatitis) has many presentations in children and adolescents, ranging from intrauterine congenital onset with sequelae of early exocrine pancreatic insufficiency as in the diseases of cystic fibrosis and Shwachman-Diamond syndrome to postnatal onset as a consequence of embryologic anomalies affecting pancreatic drainage postulated to exist in pancreas divisum, or of traumatic, obstructive, hemodynamic, metabolic or biochemical insults. The etiology is often elusive with up to 30% of cases being idiopathic. Modern imaging modalities of endoscopic ultrasonography and magnetic resonance cholangiopancreatography extend the diagnostic power of conventional abdominal ultrasonography and computed tomography. In addition, there is increasing pediatric experience with endoscopic retrograde cholangiopancreatography. Medical management remains supportive, with optimal timing and indications for surgery in cases of pancreatic necrosis and pseudocyst assessed. Three temporal patterns of pancreatitis appear in children: acute pancreatitis, recurrent acute pancreatitis, and chronic pancreatitis. Acute pancreatitis is of abrupt onset, often attributable to a specific cause, and of variable severity and duration but self-limited with eventual resolution. Acute attacks of pancreatitis recurring after periods of remission characterize acute recurrent pancreatitis and indicate an intrinsic problem or susceptibility. Chronic pancreatitis is present in most of these cases in which pancreatic inflammation and destruction never completely remits.

Nasal septal perforation: a rare extraintestinal manifestation of Crohn's disease

Nasal manifestations of Crohn's disease are quite rare. They are typified by chronic mucosal inflammation, obstruction, bleeding, and occasionally septal perforation--signs and symptoms that are common to many disease states of the nose. Nasal findings, much like oral lesions, can precede the more typical gastroenterologic manifestations of Crohn's disease. Otolaryngologists should be aware of such an association and consider the diagnosis of Crohn's disease in atypical cases of nasal disease. We report the case of a 12-year-old boy who had severe Crohn's disease and a nasal septal perforation, and we discuss this complication in the context of its otolaryngologic manifestations.

Growth of children with a functionally single ventricle following palliation at moderately increased altitude

The bidirectional Glenn and Fontan procedures are empirically performed as interim and definitive procedures in children with a functionally single ventricle. The optimal stage of palliation, nonetheless, remains unknown. During childhood, growth is a fundamental measure of response to therapy. Growth may be influenced by the degree of cyanosis, the volume load on the ventricle, and cardiac performance. Thus, the weight and stature of children with a functionally single ventricle who underwent a bidirectional Glenn procedure or a Fontan procedure were studied to determine the effect of each intervention on growth. Z scores for weight and stature were retrospectively determined prior to palliation, at yearly intervals for 4 years, and from long-term measurements until 18 years of age in all patients with at least 2 years of observation following palliation. Growth was evaluated in 54 patients with a bidirectional Glenn procedure, and 65 patients with a Fontan procedure. The Z scores for weight were improved after each method of surgical palliation. Stature, however, was improved only following the bidirectional Glenn procedure. Growth was impaired in patients who developed protein losing enteropathy. Weight improved only during the initial 2 years after the Fontan procedure in patients who had a surgical fenestration. Over the long-term, patients who underwent a Fontan procedure were more likely to have a Z score less than -2.0 for weight and stature than patients who underwent only a bidirectional Glenn procedure. Late mortality and the incidence of heart transplantation were increased in patients who experienced a decrease in their rate of growth, defined as a negative change of more than one Z score in weight or stature, following the Fontan procedure. In conclusion, at moderately increased altitude, children with a functionally single ventricle grow more appropriately following the bidirectional Glenn procedure than following the Fontan procedure. A decrease in the rate of growth is associated with a poor prognosis following the Fontan procedure.

Yersinia enterocolitis mimicking Crohn's disease in a toddler

A 31/2-year-old girl presented with persistent abdominal pain, fever, vomiting, and diarrhea accompanied by rash, oral ulceration, anemia, and an elevated sedimentation rate. Initial evaluation revealed no pathogens and was extended to include abdominal ultrasound and computed tomography showing marked ileocecal edema and mesenteric adenopathy. Colonoscopy revealed focal ulceration from rectum to cecum with histology of severe active colitis with mild chronic changes. Enteroclysis demonstrated a nodular, edematous terminal ileum. Because of the patient's clinical deterioration despite antibiotics, these features were construed consistent with Crohn's disease, and glucocorticoid therapy was begun. By the ninth hospital day, admission cultures grew Yersinia enterocolitica, and trimethoprim/sulfamethoxazole was begun followed by prompt clinical improvement. The delay in diagnosis afforded an unusually comprehensive clinical description of the presentation and diagnosis of Yersinia enterocolitis in childhood.

Are scintiscans accurate in the selection of reflux patients for pyloroplasty?

BACKGROUND

Gastric emptying scintiscans are currently used to select reflux patients for added pyloroplasty at the time of fundoplication. The accuracy of this scan selection approach has been assumed. If preoperative scintiscans do not reliably predict postfundoplication gastric emptying, however, the decision to add pyloroplasty to the fundoplication operation may be inappropriate and even harmful.

METHODS

The authors studied 27 children prospectively before and after gastric fundoplication. Gastric emptying at 60 minutes was measured by double isotopic labeling of liquid (111In) and solid (99mTc) phases of a test meal specifically designed for label fixation. The authors' question involved the accuracy of preoperative gastric scintiscans in predicting postfundoplication delay of gastric emptying (DGE). An evaluation of pyloroplasty as an effective treatment for DGE was not part of the study design. Pyloroplasty was performed as a secondary operation in three of the study children, however, because they persisted with unrelieved symptoms of retching, fullness, and abdominal discomfort. Scintiscan-documented postfundoplication delay in gastric emptying was present in all three patients at 18, 58, and 12 weeks, respectively. Additional scintiscans were performed in these patients after pyloroplasty.

RESULTS

Gastric emptying of solids at 60 minutes did not show a significant change after a gastric fundoplication operation, although the trend was in the direction of a decrease (paired t test, P= .13). Liquid emptying at 60 minutes, however, was significantly increased (paired t test, P = .01). The variation in values between patients was wide, and the correlation between pre- and postoperative study results in the same patient was poor (r2 = 0.337 for solids and r2 = 0.116 for liquids). Most unexpectedly, scintiscans after postfundoplication pyloroplasty in the three patients with persistent symptoms showed no improvement in delayed gastric emptying on repeat scintiscan 42 to 117 weeks later.

CONCLUSIONS

The data suggest that preoperative scintiscan evidence for postfundoplication DGE is probably accurate for solid emptying but not for liquids, at least as measured by the double isotope methodology of our study. Preoperative scintiscans that use a liquid phase label only may be highly misleading for the prediction of postfundoplication DGE. Furthermore, pyloroplasty may not be useful as treatment even when postfundoplication delay in gastric emptying can be accurately anticipated or confirmed. A fundamental motility disorder of the gastric body seems to be more important than muscular resistance at the gastric outlet as a cause for postfundoplication DGE, and the most effective treatment approach remains unclear.

Procedural medicine. Is your number up?

It is commonly argued that maintaining competence in procedural medicine requires the continuing practice of minimum numbers of procedures. While these continuing practice requirements may pose few problems for doctors working in city or regional hospitals, they may be impossible to meet in rural general practice. The authors review the literature relating to psychomotor skills in procedural medicine and argue that there is little or no evidence to justify the judging of competency by numbers of procedures performed. Instead it appears that with appropriate initial training, doctors can be expected to retain their psychomotor skills even after lengthy periods without practice.

The human intestinal response to enteral nutrients: a review

This review identifies the factors which influence mucosal integrity during enteral nutrition. These include biliary and pancreatic secretions, trophic influences of endocrine and gastrointestinal polypeptides, intestinal blood flow, and innervation. Fiber, bacterial fermentation products, purines, and glutamines are potential essential nutrients which may not be provided by parenteral nutrition. However, contrary to experience in animal models, the specific advantages of intraluminal delivery of nutrients for the maintenance of mucosal integrity and structure remain unproven in the human. Current evidence in the human suggests that changes in small bowel structure and function when enteral nutrients are excluded are minor and rapidly reversible as long as general nutritional status is maintained.

Effects of the pyrrolizidine alkaloid heliotrine on cell division and chromosome breakage in cultures of leucocytes from the marsupial Potorous tridactylus

Heliotrine causes an almost complete suppression of cell division in leucocyte cultures at a concentration of 2 X 10-4M; below 1 X 10-6M, its effect on the mitotic index is very slight. The mean interval for cells to enter first mitosis is extended by 10 hr with 5 X 1O-5M heliotrine. Both chromosome and chromatid breaks are produced at this latter concentration of heliotrine, the total damage being approxi. mately equivalent to that produced by 300 r of X-irradiation delivered at 25 rJmin. The chromosome breakage is considered to be true chromosome damage since it appears in cells in first division following treatment. Thus it would appear that heliotrine is capable of breaking the chromosomes in G1. i.e. before DNA synthesis. Most alkylating agents do not demonstrate any capacity to induce breakage before the replicating phase. Breakage in G1 has been demonstrated by treatment with hydroxylamine and 8-ethoxycaffeine with which the action ofheliotrine is compared.

Nonlinear analysis of the baroreceptor reflex system

The regulation of blood pressure by the baroreceptor reflex was examined in anesthetized dogs. The receptor feedback path was broken by surgical intervention, the input (carotid sinus pressure) was controlled by an external servo system, and simultaneous records of input and output (systemic arterial pressure) were obtained. A variety of pressure waveforms were applied to the carotid sinus so that the nonlinear behavior could be explored thoroughly. Most of the input waveforms consisted of relatively small signals about an operating point in the normal blood pressure range.

The nonlinear behavior of the reflex was illustrated in a number of ways. Square waves, sinusoids, and short pulses produced asymmetric arterial pressure waveforms. An overshoot in the arterial pressure always followed the rising edge of the input square wave, but was generally absent following the negative-going part of the square wave. Either positive or negative pulses caused a transient drop in arterial pressure. The sinusoidal response was often distorted, with the falling portion of the output waveform steeper than the rising portion. The system behaved as a rectifier, or envelope-detector, as illustrated by 1) the decrease in mean arterial pressure when either the amplitude or the frequency of a sinusoidal input was increased and 2) the appearance in the arterial pressure waveform of a component correlated with the envelope of a modulated carrier. Another nonlinear phenomenon was the decrease in low-frequency sinusoidal gain caused by the addition of a high-frequency sinusoid to the sinus pressure waveform. This behavior indicates that if closed loop behavior in the intact animal is to be predicted from the open loop sinewave response, the effects of the cardiac pressure pulse must be considered.

A model was constructed from standard electronic components to simulate the input-output behavior of the baroreceptor reflex. The model was able to simulate the response to high- and low-frequency sinusoids and to reproduce the essential features of the square-wave and pulse responses. On this basis the model was considered adequate for simulating the performance of the baroreceptor reflex in certain open loop and closed loop situations.