Orthodontic correction of anterior open bite using skeletal anchorage: systematic review and meta-analysis

The purpose of this study was to investigate the scientific evidence on the short- and long-term effects of orthodontic correction of anterior open bite (AOB) using skeletal anchorage (SA). Clinical studies on the use of SA for AOB in patients with permanent dentition, or at least 12 years of age, were searched. Short- and long-term (≥2 years) outcomes were collected. Mean differences were calculated from pooled data. Twenty-four eligible articles with a total of 362 subjects were selected for inclusion in the meta-analysis. There was a significant increase in overbite (3.88 mm, P < 0.001) and maxillary molar intrusion (-2.15 mm, P < 0.001). The mandible showed counterclockwise rotation with anterosuperior chin movement (all P < 0.001). Long term, the decrease in overbite was 19.9% and decrease in molar intrusion was 22.9%. The decrease in the mandibular projection was 14.6% for ANB (A-point-nasion-B-point angle) and 46.2% for mandibular anteroposterior position. The overall risk of bias in the included studies was rated as moderate to high, and publication bias existed for several key variables. SA for maxillary molar intrusion effectively improved dental and skeletal outcomes, but there was a long-term decrease in overbite and maxillary molar position. The variable data quality, heterogeneity, and publication bias in investigated outcomes are limitations in interpreting the findings.

228 Resilience, Mindset and Burnout of Healthcare Workers During the COVID-19 Pandemic

Introduction

We investigated the impact of the Biopsychosocial challenges associated with the COVID-19 Pandemic on the Healthcare Workforce, exploring the impact on and relationship between Healthcare Workers’ Mindset, Resilience and Burnout.

Method

An electronic survey was distributed to Healthcare Workers through Professional Associations' websites and social media. The survey contained demographic questions, a Burnout Inventory, a General Resilience scale, a scale to assess for Resilience during the Pandemic, as well as an Adapted Dweck Mindset instrument to measure Mindset as related to Workplace Environment and Resilience. Univariate and multivariate analysis was undertaken to examine the relationship between these factors.

Results

1,370 healthcare workers completed the questionnaire. 58.5%, 25.4%, 28.5% reported having Burnout, Low General Resilience and Low COVID Resilience, respectively. Burnout was significantly associated with Fixed Mindset, Low General Resilience and Low COVID Resilience. Resilience Training was found to be protective for Burnout.

Conclusions

The COVID-19 Pandemic has led to a higher proportion of HCWs experiencing Burnout than previously reported. Our findings demonstrate that HCWs with Low Resilience and Fixed Mindsets are more likely to experience Burnout, suggesting that, in combination with improved institutional support, there is a role for personalised Resilience and Mindset Training, in helping reduce the proportion of HCW Burnout.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Molecular Diversity of Mycobacterium tuberculosis Strains in Northwestern Iran

Background

Years after the development of antituberculosis (TB) drugs, many people continue to suffer from this disease. To control the spread of TB, strains of the Mycobacterium tuberculosis complex need to be determined, and sources of infection must be identified. Such steps should help to prevent transmission of the infection.

Objectives

The aim of this study was to perform molecular genotyping of isolates of the M. tuberculosis complex obtained from patients in northwestern Iran.

Methods

One hundred ninety-four culture-positive M. tuberculosis isolates obtained from patients in northwestern Iran were analyzed using the mycobacterial interspersed repetitive unit-exact tandem repeats (MIRU-ETR) method.

Results

The MIRU-ETR method distinguished 162 different patterns in the 194 isolates, comprising 23 clusters and 139 unique patterns. Its discriminatory power according to the Hunter-Gaston discriminatory index (HGDI) was 0.9978. The largest cluster contained six isolates.

Conclusions

This research indicated that various strains of M. tuberculosis were responsible for TB and that the majority of cases were due to reactivation.

Arch width changes in patients with Class II division 1 malocclusion treated with maxillary first premolar extraction and non-extraction method

Background

The aim of this study was to determine arch width changes during maxillary first premolars extraction and non-extraction treatment in patients with Class II division 1 malocclusion.

Material and Methods

Dental casts of 91 Class II division 1 patients (36 males and 55 females) were evaluated. The minimum age of the subjects at the beginning of treatment was above 16 years. 48 patients were treated with extraction of the maxillary first premolars and 43 patients were treated without extraction. Pre- and post-treatment maxillary and mandibular inter-canine and inter-molar arch widths were measured.

Results

At the end of treatment, maxillary and mandibular inter-canine widths of both groups increased significantly. The maxillary inter-molar width decreased in the extraction group and increased in the non-extraction group. The mandibular inter-molar width increased significantly in both groups. No significant differences were observed between males and females.

Conclusions

The results of this study indicated that there was a tendency for an increase in arch width during both the extraction and non-extraction treatment except maxillary inter-molar width in the extraction cases.

Key words:Dental arch, malocclusion, angle Class II, tooth movement, extraction.

Assessment of Factors Affecting Adolescent Patients' Compliance with Hawley and Vacuum Formed Retainers

INTRODUCTION

Success of orthodontic retention with removable retainers almost entirely depends on patients' compliance.

AIM

This study was carried out to investigate the relationship between adolescent orthodontic patients' compliance and various clinical and social factors.

MATERIALS AND METHODS

The data were collected from 77 orthodontic patients aged 7-11 years old who had finished the full fixed appliance therapy. Hawley's retainers were used in 34 patients and 43 patients used Vacuum Formed Retainers (VFRs). The subjects completed a questionnaire including several identifiers allowing the respondents to be classified into subgroups. They were also asked to indicate how long they wore their retainers during the day, by writing the number of hours in the report-card for the next three months. Comparison of the results was performed by one-way ANOVA and independent sample-t tests.

RESULTS

No significant differences were found between males and females. Type of the retainer, patients' grade of study, mothers' occupation, clinicians' and parents' attitudes and filling the report cards had significant effect on mean wear hours per day. When compliance of the patients was assessed according to treatment location, Living place, parents' educational degrees and ethnicity, no significant differences could be found.

CONCLUSION

The adolescent patients' compliance was greater with VFRs than with Hawley's retainers. Parental attitude and doctor-patient relationship had a great impact on adolescent patients' compliance.

Shear bond strength and debonding characteristics of metal and ceramic brackets bonded with conventional acid-etch and self-etch primer systems: An in-vivo study

Background

Different in-vitro studies have reported various results regarding shear bond strength (SBS) of orthodontic brackets when SEP technique is compared to conventional system. This in-vivo study was designed to compare the effect of conventional acid-etching and self-etching primer adhesive (SEP) systems on SBS and debonding characteristics of metal and ceramic orthodontic brackets.

Material and Methods

120 intact first maxillary and mandibular premolars of 30 orthodontic patients were selected and bonded with metal and ceramic brackets using conventional acid-etch or self-etch primer system. The bonded brackets were incorporated into the wire during the study period to simulate the real orthodontic treatment condition. The teeth were extracted and debonded after 30 days. The SBS, debonding characteristics and adhesive remnant indices (ARI) were determined in all groups.

Results

The mean SBS of metal brackets was 10.63±1.42 MPa in conventional and 9.38±1.53 MPa in SEP system, (P=0.004). No statistically significant difference was noted between conventional and SEP systems in ceramic brackets. The frequency of 1, 2 and 3 ARI scores and debonding within the adhesive were the most common among all groups. No statistically significant difference was observed regarding ARI or failure mode of debonded specimens in different brackets or bonding systems.

Conclusions

The SBS of metal brackets bonded using conventional system was significantly higher than SEP system, although the SBS of SEP system was clinically acceptable. No significant difference was found between conventional and SEP systems used with ceramic brackets. Total SBS of metal brackets was significantly higher than ceramic brackets. Due to adequate SBS of SEP system in bonding the metal brackets, it can be used as an alternative for conventional system.

Key words:Shear bond strength, Orthodontic brackets, Adhesive remnant index, self-etch.

Volume shifts, unfolding and rolling of haustra in the isolated guinea pig caecum

The large intestine extracts water from chyme and compacts chyme into faecal conglomerates; it is unclear what role the special pockets known as colonic haustra have in these events. Here we monitored the movements of haustra in isolated preparations of guinea pig caecum using videocamera and ultrasound and related them to contractions of muscle flaps and movements of glass beads in haustral pockets. We found that in partially filled caecal loops localized contractions of taeniae shift volume back and forth between adjacent haustra; volume unfolds haustral walls in a characteristic sweep with sequential intrahaustral folds popping out; cyclic contractions and relaxations of the fold then produce the caterpillar-like movement known as haustral rolling; ultrasound showed that haustral rolling made the haustral flow channel narrower and longer as haustral folds increase their height from 7.5 +/- 1.5 mm to 16 +/- 4 mm and their distance from 4.1 +/- 0.2 mm to 7.9 +/- 0.3 mm; luminal contents were alternatively shaken off the haustral wall, whirled around the lumen or left to settle. We also suspended the row of haustra between two taeniae inside a frame and attached flaps of taeniae and haustral folds to strain gauges to record their mechanical activity; both taeniae and haustral folds produced an undulating baseline tension; during rolling, folds produced phasic contractions at 17 +/- 2 cycles min-1 which propagated distally across haustral septa; rolling constantly shuffled around glass beads placed inside the haustra. When we stimulated the intramural nerves to the caecum through bipolar electrodes, all contractile activity was temporarily inhibited and haustral septa flattened; a rebound contraction then propagated aborally from the caecal pole and swept the glass beads ahead of it. Thus, tonic contractions of taeniae shift caecal contents back and forth across haustral septa; expansion of haustra triggers haustral rolling which shuffles contents; both these movements produce local flow within and between haustra which might enhance the separation of solid and liquid colonic contents.

Role of altered responsiveness of hypertrophic smooth muscle in manometric abnormalities of the obstructed opossum oesophagus

The movements of the obstructed oesophagus are abnormal, but whether this relates to the disease causing the obstruction, to the altered load conditions or to abnormal neuromuscular functions in hypertrophic smooth muscle is unclear. In an opossum model of chronic oesophageal obstruction, we compared the mechanical responsiveness of hypertrophic smooth muscle in vitro to in vivo manometric function. Related to their greater thickness, strips of hypertrophic muscle generated greater force in response to electrical stimulation and to stretch than control strips. Hypertrophic muscle often generated repetitive contractions; spread of contractions orad from the stimulus site was common in hypertrophic oesophageal bands. On manometry, the obstructed oesophagus generated abnormally high pressures proximally, and highly variable pressure amplitudes in the middle and distally; pressure waves often occurred simultaneously throughout the oesophagus, were repetitive or multi-peaked and led to a lasting rise of oesophageal pressure. Alterations in the intrinsic neuromuscular functions of hypertrophic smooth muscle including generation of greater force, repetitive or spontaneous contractions, and retrograde spread of contractions explain many, but not all, of the manometric abnormalities seen in the chronically obstructed oesophagus.

Preservation of peristaltic reflex in hypertrophied ileum of guinea pig

Chronic obstruction of the guinea pig ileum leads to distension and muscular hypertrophy, but how this affects passive biomechanical and nerve-mediated contractions and clearance known as peristaltic reflex is unclear. Ileum of controls had a diameter of 3.0 +/- 1.1 mm and a circular muscle thickness of 37.2 +/- 11.2 microns; 4 wk after placement of a nonconstricting Gore-Tex band, the ileum was distended to 10.0 +/- 0.19 mm, and its muscle had hypertrophied to 195.0 +/- 61.2 microns. Hypertrophied segments exceeded controls in capacity (e.g., 5.1 +/- 1.1 vs. 1.1 +/0 0.2 ml at 6 cm), compliance, and hysteresis. Threshold volumes and pressures that triggered the reflex were 3.3 +/- 1.3 ml and 3.1 +/- 0.01 mmHg in hypertrophied vs. 0.7 +/- 0.2 ml and 1.5 +/- 0.2 mmHg in controls. The diameter increase that triggered the reflex was 1.4 +/- 0.1 mm in hypertrophied segments and 0.6 +/- 0.1 mm in controls. Hypertrophied segments generated fewer contractions of virtually double the amplitude and failed to generate a pressure differential between up- and downstream sites as controls did. Hypertrophied segments generated larger stroke volumes and cumulative clearance than controls. The ratio of antegrade to retrograde clearance was similar in hypertrophied and control segments. The length of the occluding segment in hypertrophied preparations exceeded that of controls. Control contractions indented the antimesenteric border and propagated antegrade from their site of origin; bizarre writhing movements of hypertrophied segments made their contractions difficult to monitor. Thus distension and muscular hypertrophy do not interfere with the ability of the chronically obstructed guinea pig ileum to generate a peristaltic reflex at least as readily and as powerful and as effective in clearing the lumen as controls.

Cecum of guinea pig is a reservoir and sigmoid is a high-resistance conduit

We compared the filling responses of the cecum and the sigmoid of the guinea pig using volumes up to 60 ml and 2.5 ml, respectively. In the isolated cecum, each 1-cm increment of hydrostatic pressure above zero led to accommodation of 10 ml volume; in the sigmoid, the yield pressure (at which accommodation first occurred) was 6 cm H2O, and pressure increments up to 20 cm H2O produced volume increments of less than 0.5 ml. Resting pressure at half-maximal filling was 5.0 +/- 0.7 cm H2O for the sigmoid and 1.7 +/- 0.6 cm H2O for the cecum. K+ depolarization led to a significant upward shift in the pressure curves of both segments. Ca2+ withdrawal decreased sigmoid and cecal pressures at some volumes. Distension of the cecum triggered intermittent contractions, which began with the shortening of the teniae and were associated with low-amplitude pressures and expulsion of a 5- to 10-ml volume. Distension of the sigmoid produced propagating contractions that were associated with high-amplitude pressures and lengthening; compartmentalization in the sigmoid prevented efflux from it, and volume inflow was not affected by pressure waves. Our observations indicate that its large capacity and great distensibility make the cecum suitable for reservoir functions, whereas its narrowness and lack of distensibility make the sigmoid a high-resistance conduit.

Dynamic imaging of obstructed opossum esophagus. From altered load to altered contractility

We studied by barium contrast the dynamics of experimental obstruction in the opossum esophagus. Immediately after banding the gastroesophageal junction, entrapment of the bolus between the band and the peristaltic contraction led to esophageal bulging, forceful retropulsion of the bolus at the band, and the repeated triggering of peristaltic contractions by the retropelled bolus. In ensuing weeks, triggering of contractions became more difficult and contractions led to bizarre "corkscrew" movements of the increasingly distended and tortuous esophagus. A tight contraction ring that moved very slowly retrograde was occasionally observed in the chronically distended esophagus. Computer-assisted analysis showed that the area and perimeter of the bolus were abnormally large in chronic obstruction and that during its passage through the esophagus the compactness of the bolus increased no longer. Configurational analysis of the cone that the peristaltic contraction shapes at the tail of the barium column showed this to narrow progressively on passage through the normal esophagus and, paradoxically, to widen in both acute and chronic obstruction.

Morphological changes of myenteric neurons in the partially obstructed opossum esophagus

We have previously described a model of partial esophageal obstruction which leads to hypertrophic and degenerative changes in the smooth muscle cells. In the present communication we describe changes occurring in the myenteric plexus including increased thickness, varicosities and irregular angulations of nerve fiber bundles. The perikarya of myenteric neurons in the obstructed esophagus showed elongated mitochondria, dilated cisternae of the endoplasmic reticulum and increased numbers of secondary lysosomes and multimembranous dense bodies. In myenteric axons, there was infiltration of Schwann cell subunit by collagen fibrils.

Infiltration of hypertrophic esophageal smooth muscle by mast cells and basophils

Partial obstruction leads to chronic distension and muscular hypertrophy of the opossum esophagus. The smooth muscle cells of the circular muscle layer enlarge, become pleomorphic and are surrounded by an amorphous ground substance in the extracellular space. Here we describe the histological and ultrastructural features of a peculiar cellular infiltrate in the hypertrophic smooth muscle. The infiltrate consisted uniquely of mast cells and basophils. In per unit area, the number of mast cells increased from 0.9 +/- 0.1 cells in controls to 3.7 +/- 0.2 in hypertrophic smooth muscle; the corresponding numbers for basophils were 2.5 +/- 0.2 and 7.2 +/- 0.3 cells. Cells were seen primarily in the septal spaces of the circular muscle layer and at the interface of the circular and longitudinal muscle layer. The cytoplasm of basophils is normally packed with round and oval granules. The granules stain metachromatically and with varying intensity on Wright-Giemsa stains. On transmission electronmicroscopy, granules display a membrane and a great diversity in the structure of their luminal contents. In hypertrophic muscle, most granules were discharging their contents into the cytoplasm or extracellular space. The membranes of adjacent empty granules then fused to form a chain of vacuoles. Similar changes occurred also in the mast cells which differed from the basophil by their lack of nuclear lobulation and by the greater homogeneity of their cytoplasmic granules. It is possible that these inflammatory cells are involved in the reconstruction of the smooth muscle and its connective tissue which occur during esophageal distension and hypertrophy.

Hypertrophic smooth muscle in the partially obstructed opossum esophagus. Excitability and electrophysiological properties

Partial obstruction of the opossum esophagus leads to thickening of the circular muscle, hypertrophy of smooth muscle cells, and diminution of the extracellular space. The pharmacological and electrophysiological properties of this hypertrophied muscle were studied. Carbachol produced phasic and tonic contractions of the circular muscle. The EC50 for tonic contractions was greater for hypertrophied than for normal muscle (21.1 +/- 3.9 mumol/L vs. 4.8 +/- 2.2 mumol/L; P less than 0.05). The resting membrane potential difference of hypertrophied muscle (-50.8 +/- 0.2 mV) was similar to that of normal muscle (-50.0 +/- 0.2 mV). Electrical stimulation of intrinsic nerves in the normal muscle produced a hyperpolarization followed by a depolarization of smooth muscle membrane potential. Hypertrophied muscle responded either with an attenuated hyperpolarization or no hyperpolarization, both of which were followed by a depolarization. The space constant in the long axes of the hypertrophied circular muscle cells was greater than normal (4.4 +/- 0.2 mm vs. 3.4 +/- 0.1 mm; P less than 0.001). The threshold potential for initiation of action potentials was more negative for hypertrophied (-43.2 +/- 0.4 mV) than for normal circular muscle (-41.6 +/- 0.2 mV; P less than 0.005). These data indicate that alterations in neuromuscular function accompany the hypertrophy of esophageal smooth muscle.

Motility changes in opossum esophagus from experimental esophagitis

We assessed how acute inflammation affects the contractile activity of the esophageal body. Two models of esophagitis were used: nine opossums had an esophageal perfusion of 100 meq hydrochloric acid for 2 hr and were studied at 24 hr. Ten had the perfusion for 4 h and their esophagitis were studied in vitro after 72 hr. Comparisons were made in all instances to animals who had esophageal saline perfusion for identical periods. All acid-perfused animals developed gross and histologic evidence of mucosal inflammation; in three animals, inflammatory changes extended into the submucosa and the muscularis propria. Manometric recordings in the acid-perfused animals revealed esophageal shortening, frequent failure of primary peristalsis and frequent occurrence of spontaneous contractions. Recordings of isometric tension of muscle in vitro revealed spontaneous contractions in strips from the mucosa and from the circular and from the longitudinal muscle. The amplitude of contractions in response to electrical stimulation was decreased, but the duration of contractions was increased largely because of a prolonged recovery phase. These changes in mechanical response occurred with stimulus parameters directed at both the muscle and the intrinsic nerves. We conclude that esophageal inflammation can lead to an increased irritability and decreased stimulus response of the smooth muscle of the esophagus even where it is not directly involved in an inflammatory response. These changes correspond to the functional abnormalities of the esophagus seen in patients with reflux esophagitis.

Anorectal manometry in active and quiescent ulcerative colitis

Anorectal function was measured in 11 patients with active medically intractable ulcerative colitis, seven patients with quiescent ulcerative colitis, and 18 healthy subjects. The anal resting pressure, squeeze pressure, and ability to defecate a balloon were similar in all groups. Significantly lower rectal distention volumes were required for rectal sensation, critical volume, and to induce rectal contractility in patients with active disease compared to controls or patients with quiescent disease. Rectal compliance was significantly reduced in patients with active and quiescent disease. The increased rectal sensitivity and contractility in patients with active colitis appear to be related to active mucosal inflammation and ulceration. Episodes of mucosal inflammation may be responsible for chronic changes in the rectal wall resulting in fibrosis and decreased compliance in patients with quiescent disease. The frequency and urgency of defecation and the fecal incontinence may be due to a hypersensitive, hyperactive, and poorly compliant rectum.

Rectosigmoid motility in patients with quiescent and active ulcerative colitis

We studied the pathophysiology of diarrhea in ulcerative colitis by evaluating and comparing rectosigmoid motility before, during, and after a 900-cal meal in healthy subjects, patients with quiescent ulcerative colitis, and patients with active ulcerative colitis. Three intraluminal pressure transducers were used for recording of rectosigmoid motility. Motility during fasting, eating, and after eating a meal was similar in patients with quiescent disease and controls. Motility increased significantly during eating in controls, but not in patients with quiescent disease. In patients with active colitis, motility was significantly reduced during fasting, eating, and after eating, compared with controls. Motility increased significantly during eating in patients with active disease. Propagated activity was similar in the three study groups; therefore, the decreased motility was due to decrease in segmental contractions. These findings suggest that diarrhea in patients with active colitis may be related to the loss of normal segmental contractions which delay distal stool transport.

Duodenal resistance to the emptying of various solutions from the isolated cat stomach

Experiments were conducted to determine to what extent the duodenum resists the emptying of various solutions from the isolated stomach. Cat stomachs were maintained in Krebs solution in vitro, and filled with 100 ml isotonic saline solution, isotonic glucose, hypertonic saline solution, hypertonic glucose, or dilute acid. Gastric pressure was constantly monitored; gastric output was collected constantly by a cannula in the proximal or distal duodenum. For all solutions, cumulative gastric output at all times was considerably less with the distal than the proximal cannula position. This difference was almost entirely caused by a smaller fractional gastric output during the first minute of gastric emptying, and by reduced amplitude of the gastric stroke volume with the distal cannula position. Some differences were observed in the gastric emptying rate for the various solutions; isotonic saline solution emptied particularly slowly and hydrochloric acid emptied particularly fast. In addition, the various solutions produced different gastric pressure patterns, which could not be entirely explained by differences in residual gastric volume. We concluded that the cat duodenum provides a resistance to gastric emptying over and above that generated by the pylorus, and that the duodenal resistance is caused by limitations in duodenal capacity. It is furthermore concluded that the mechanical activity of the isolated stomach and duodenum is affected by the chemical composition of their luminal contents.

Ion transport in human cecum, transverse colon, and sigmoid colon in vitro. Baseline and response to electrical stimulation of intrinsic nerves

In a flux chamber study of ion transport in human colon, we compared baseline rates with those measured during electrical stimulation of intrinsic nerves. In baseline studies, sodium was absorbed throughout, but maximally in transverse colon. In cecum, sodium absorption accounted for the short circuit current and chloride was not absorbed. Chloride was absorbed in transverse and sigmoid colon, however. Residual current was minimal in cecum and transverse colon, but increased in sigmoid colon. Neural stimulation caused chloride secretion in cecum, reduced chloride absorption in sigmoid colon, but caused no change in transverse colon; sodium absorption decreased in cecum. A neurotransmitter of unknown identity affects baseline short circuit current in sigmoid colon. Half of the increase in short circuit caused by neural stimulation in sigmoid colon is mediated by muscarinic receptors. The identity of the other transmitter(s) is not known. It is not substance P or histamine. The three divisions of the colon differ in relative rates of baseline ion transport and in their transport responses to intrinsic nerve stimulation.

Surgical treatment in familial visceral myopathy

In a kindred with a familial visceral myopathy, seven patients had operations seeking relief of chronic abdominal pain and other symptoms of intestinal obstruction; one patient had an 80% cystectomy and a Y-V-plasty of the bladder neck for urinary retention. Five patients with megaduodenum had bypass operations; a side-to-side duodenojejunostomy was done in four and a retrocolic gastrojejunostomy in one. Two of these died of postoperative complications, and one developed symptomatic adhesions. Two other patients who had duodenojejunostomy have done well for 6 years and 1 1/2 years respectively. One patient with dilation of the distal jejunum and proximal ileum had relief of intestinal obstructive symptoms from jejunostomy to decompress the destal jejunum. One patient who had a resection of the descending and sigmoid colon for sigmoid volvulus has done well for four years. Three of these seven patients developed peritonitis postoperatively, and two had symptomatic adhesions after operations. Duodenal aspiration from a patient who developed postoperative peritonitis grew E. coli, 10(13) colonies per ml. After review of the results of operations in other families and in our kindred, we favor side-to-side duodenojejunostomy in megaduodenum. Duodenal aspirate must be cultured before operation. Evidence of bacterial overgrowth in the aspirate should prompt appropriate antibiotic treatment to reduce the likelihood of sepsis.