Revisiting the two rhythm generators for respiration in lampreys

In lampreys, respiration consists of a fast and a slow rhythm. This study was aimed at characterizing both anatomically and physiologically the brainstem regions involved in generating the two rhythms. The fast rhythm generator has been located by us and others in the rostral hindbrain, rostro-lateral to the trigeminal motor nucleus. More recently, this was challenged by researchers reporting that the fast rhythm generator was located more rostrally and dorsomedially, in a region corresponding to the mesencephalic locomotor region. These contradictory observations made us re-examine the location of the fast rhythm generator using anatomical lesions and physiological recordings. We now confirm that the fast respiratory rhythm generator is in the rostro-lateral hindbrain as originally described. The slow rhythm generator has received less attention. Previous studies suggested that it was composed of bilateral, interconnected rhythm generating regions located in the caudal hindbrain, with ascending projections to the fast rhythm generator. We used anatomical and physiological approaches to locate neurons that could be part of this slow rhythm generator. Combinations of unilateral injections of anatomical tracers, one in the fast rhythm generator area and another in the lateral tegmentum of the caudal hindbrain, were performed to label candidate neurons on the non-injected side of the lateral tegmentum. We found a population of neurons extending from the facial to the caudal vagal motor nuclei, with no clear clustering in the cell distribution. We examined the effects of stimulating different portions of the labeled population on the respiratory activity. The rostro-caudal extent of the population was arbitrarily divided in three portions that were each stimulated electrically or chemically. Stimulation of either of the three sites triggered bursts of discharge characteristic of the slow rhythm, whereas inactivating any of them stopped the slow rhythm. Substance P injected locally in the lateral tegmentum accelerated the slow respiratory rhythm in a caudal hindbrain preparation. Our results show that the fast respiratory rhythm generator consists mostly of a population of neurons rostro-lateral to the trigeminal motor nucleus, whereas the slow rhythm generator is distributed in the lateral tegmentum of the caudal hindbrain.

Post coronavirus disease mucormycosis: a deadly addition to the pandemic spectrum

OBJECTIVE

To study the possible association between invasive fungal sinusitis (mucormycosis) and coronavirus disease.

METHODS

A prospective observational study was conducted at a tertiary care centre over four months, involving all patients with mucormycosis of the paranasal sinuses suffering from or having a history of coronavirus disease infection.

RESULTS

Twenty-three patients presented with mucormycosis, all had an association with coronavirus disease 2019. The ethmoids (100 per cent) were the most common sinuses affected. Intra-orbital extension was seen in 43.47 per cent of cases, while intracranial extension was only seen in 8.69 per cent. Diabetes mellitus was present in 21 of 23 cases, and was uncontrolled in 12 cases. All patients had a history of steroid use during their coronavirus treatment.

CONCLUSION

New manifestations of coronavirus disease 2019 are appearing over time. The association between coronavirus and mucormycosis of the paranasal sinuses must be given serious consideration. Uncontrolled diabetes and over-zealous use of steroids are two main factors aggravating the illness, and both of these must be properly checked.

Relating gastric scintigraphy and symptoms to motility capsule transit and pressure findings in suspected gastroparesis

BACKGROUND

Wireless motility capsule (WMC) findings are incompletely defined in suspected gastroparesis. We aimed to characterize regional WMC transit and contractility in relation to scintigraphy, etiology, and symptoms in patients undergoing gastric emptying testing.

METHODS

A total of 209 patients with gastroparesis symptoms at NIDDK Gastroparesis Consortium centers underwent gastric scintigraphy and WMCs on separate days to measure regional transit and contractility. Validated questionnaires quantified symptoms.

KEY RESULTS

Solid scintigraphy and liquid scintigraphy were delayed in 68.8% and 34.8% of patients; WMC gastric emptying times (GET) were delayed in 40.3% and showed 52.8% agreement with scintigraphy; 15.5% and 33.5% had delayed small bowel (SBTT) and colon transit (CTT) times. Transit was delayed in ≥2 regions in 23.3%. Rapid transit was rarely observed. Diabetics had slower GET but more rapid SBTT versus idiopathics (P ≤ .02). GET delays related to greater scintigraphic retention, slower SBTT, and fewer gastric contractions (P ≤ .04). Overall gastroparesis symptoms and nausea/vomiting, early satiety/fullness, bloating/distention, and upper abdominal pain subscores showed no relation to WMC transit. Upper and lower abdominal pain scores (P ≤ .03) were greater with increased colon contractions. Constipation correlated with slower CTT and higher colon contractions (P = .03). Diarrhea scores were higher with delayed SBTT and CTT (P ≤ .04).

CONCLUSIONS & INFERENCES

Wireless motility capsules define gastric emptying delays similar but not identical to scintigraphy that are more severe in diabetics and relate to reduced gastric contractility. Extragastric transit delays occur in >40% with suspected gastroparesis. Gastroparesis symptoms show little association with WMC profiles, although lower symptoms relate to small bowel or colon abnormalities.

Diabetic and idiopathic gastroparesis is associated with loss of CD206-positive macrophages in the gastric antrum

BACKGROUND

Animal studies have increasingly highlighted the role of macrophages in the development of delayed gastric emptying. However, their role in the pathophysiology of human gastroparesis is unclear. Our aim was to determine changes in macrophages and other cell types in the gastric antrum muscularis propria of patients with diabetic and idiopathic gastroparesis.

METHODS

Full thickness gastric antrum biopsies were obtained from patients enrolled in the Gastroparesis Clinical Research Consortium (11 diabetic, 6 idiopathic) and 5 controls. Immunolabeling and quantitative assessment was done for interstitial cells of Cajal (ICC) (Kit), enteric nerves protein gene product 9.5, neuronal nitric oxide synthase, vasoactive intestinal peptide, substance P, tyrosine hydroxylase), overall immune cells (CD45) and anti-inflammatory macrophages (CD206). Gastric emptying was assessed using nuclear medicine scintigraphy and symptom severity using the Gastroparesis Cardinal Symptom Index.

RESULTS

Both diabetic and idiopathic gastroparesis patients showed loss of ICC as compared to controls (Mean [standard error of mean]/hpf: diabetic, 2.28 [0.16]; idiopathic, 2.53 [0.47]; controls, 6.05 [0.62]; P=.004). Overall immune cell population (CD45) was unchanged but there was a loss of anti-inflammatory macrophages (CD206) in circular muscle (diabetic, 3.87 [0.32]; idiopathic, 4.16 [0.52]; controls, 6.59 [1.09]; P=.04) and myenteric plexus (diabetic, 3.83 [0.27]; idiopathic, 3.59 [0.68]; controls, 7.46 [0.51]; P=.004). There was correlation between the number of ICC and CD206-positive cells (r=.55, P=.008). Enteric nerves (PGP9.5) were unchanged: diabetic, 33.64 (3.45); idiopathic, 41.26 (6.40); controls, 46.80 (6.04).

CONCLUSION

Loss of antral CD206-positive anti-inflammatory macrophages is a key feature in human gastroparesis and it is associates with ICC loss.

Constipation-Predominant Irritable Bowel Syndrome Females Have Normal Colonic Barrier and Secretory Function

OBJECTIVES

The objective of this study was to determine whether constipation-predominant irritable bowel syndrome (IBS-C) is associated with changes in intestinal barrier and secretory function.

METHODS

A total of 19 IBS-C patients and 18 healthy volunteers (all females) underwent saccharide excretion assay (0.1 g ¹³C mannitol and 1 g lactulose), measurements of duodenal and colonic mucosal barrier (transmucosal resistance (TMR), macromolecular and Escherichia coli Bio-Particle translocation), mucosal secretion (basal and acetylcholine (Ach)-evoked short-circuit current (Isc)), in vivo duodenal mucosal impedance, circulating endotoxins, and colonic tight junction gene expression.

RESULTS

There were no differences in the in vivo measurements of barrier function between IBS-C patients and healthy controls: cumulative excretion of ¹³C mannitol (0-2 h mean (s.e.m.); IBS-C: 12.1 (0.9) mg vs. healthy: 13.2 (0.8) mg) and lactulose (8-24 h; IBS-C: 0.9 (0.5) mg vs. healthy: 0.5 (0.2) mg); duodenal impedance IBS-C: 729 (65) Ω vs. healthy: 706 (43) Ω; plasma mean endotoxin activity level IBS-C: 0.36 (0.03) vs. healthy: 0.35 (0.02); and in colonic mRNA expression of occludin, zonula occludens (ZO) 1-3, and claudins 1-12 and 14-19. The ex vivo findings were consistent, with no group differences: duodenal TMR (IBS-C: 28.2 (1.9) Ω cm² vs. healthy: 29.8 (1.9) Ω cm²) and colonic TMR (IBS-C: 19.1 (1.1) Ω cm² vs. healthy: 17.6 (1.7) Ω cm²); fluorescein isothiocyanate (FITC)-dextran (4 kDa) and E. coli Bio-Particle flux. Colonic basal Isc was similar, but duodenal basal Isc was lower in IBS-C (43.5 (4.5) μA cm^-2) vs. healthy (56.9 (4.9) μA cm^-2), P=0.05. Ach-evoked ΔIsc was similar.

CONCLUSIONS

Females with IBS-C have normal colonic barrier and secretory function. Basal duodenal secretion is decreased in IBS-C.

High risk of post-infectious irritable bowel syndrome in patients with Clostridium difficile infection

BACKGROUND

Infectious enteritis is a commonly identified risk factor for irritable bowel syndrome (IBS). The incidence of Clostridium difficile infection (CDI) is on the rise. However, there is limited information on post-infectious IBS (PI-IBS) development following CDI and the host- and infection-related risk factors are not known.

AIM

To determine the incidence and risk factors for PI-IBS following CDI.

METHODS

A total of 684 cases of CDI identified from September 2012 to November 2013 were surveyed. Participants completed the Rome III IBS questionnaire and details on the CDI episode. Predictive modelling was done using logistic regression to evaluate risk factors for PI-IBS development.

RESULTS

A total of 315 CDI cases responded (46% response rate) and 205 were at-risk (no pre-CDI IBS) for PI-IBS development. A total of 52/205 (25%) met the Rome III criteria for IBS ≥6 months following CDI. IBS-mixed was most common followed by IBS-diarrhoea. In comparison to those without subsequent PI-IBS, greater percentage of PI-IBS patients had CDI symptoms >7 days, nausea, vomiting, abdominal pain during CDI, anxiety and a higher BMI. Using logistic regression, CDI symptoms >7 days [Odds ratio (OR): 2.96, P = 0.01], current anxiety (OR: 1.33, P < 0.0001) and a higher BMI (OR: 1.08, P = 0.004) were independently associated with PI-IBS development; blood in the stool during CDI was protective (OR: 0.44, P = 0.06).

CONCLUSIONS

In this cohort study, new-onset IBS is common after CDI. Longer CDI duration, current anxiety and higher BMI are associated with the diagnosis of C. difficile PI-IBS. This chronic sequela should be considered during active management and follow-up of patients with CDI.

Improving the detection of environmental enteric dysfunction: a lactulose, rhamnose assay of intestinal permeability in children aged under 5 years exposed to poor sanitation and hygiene

Background

Environmental enteric dysfunction (EED) is an asymptomatic intestinal disorder affecting populations living in conditions of poor sanitation and hygiene. The study tested intestinal barrier function in infants with EED.

Methods

We prospectively studied an advanced high-performance liquid chromatography mass spectrometry assay of urine collected after oral intake of the monosaccharide, L-rhamnose and the disaccharide, lactulose, in 112 children from three continents.

Findings

Compared to the US cohort (n=27), the cohorts of children from Peru (n=19) and Zambia (n=85) were older with evidence of growth impairment. The median (range) of age (months) was 8.0 (2.0 to 13.0), 27.0 (15.0 to 29.0) and 21.0 (12.0 to 36.0), respectively. The median (range) of height for age Z score was −0.1 (−1.8 to 2.4), −1.8 (−3.3 to −0.2) and −2.3 (−8.5 to 1.2), respectively. Among children with valid sugar data (n=22 USA, n=19 Peru, n=73 Zambia), there were no significant differences in the median rhamnose urine concentrations between the three groups. The median (range) lactulose concentration (µg/mL) was 6.78 (0.29 to 31.90), 47.60 (4.23 to 379.00) and 75.40 (0.67 to 873.00) in the US, Peruvian and Zambian cohorts, respectively (p<0.001). The lactulose/rhamnose ratio (LRR) was higher in cohorts from Peru (0.75, 0.15, 5.02) and Zambia (2.26, 0.08, 14.48) compared to the US (0.14, 0.06, 1.00) cohort (p<0.001). In a multivariate effect modification model, higher weight-for-age z scores were associated with lower post-dose lactulose when rhamnose excretion was constant (p=0.003).

Conclusions

This non-invasive two saccharide permeability protocol measures changes in intestinal permeability in children with EED and permits the identification of individuals for interventional trials.

Germ-free mice as a model to study effect of gut microbiota on host physiology

The alterations in resident gut microbiota seen in chronic gastrointestinal disorders have led to an increasing interest in the role of gut bacteria in maintaining intestinal barrier function. While acute alterations in colonic secretomotor function in response to pathogens have been well described, the effect of commensal bacteria on intestinal barrier function and colonic secretomotor function still remains poorly understood. Germ-free mice represent a model system to study effect of gut microbes on host gastrointestinal physiology. The study by Lomasney et al. represents an important step in this direction by demonstrating that the colonic secretomotor function is largely preserved in germ-free mice, hence making them a suitable model to study effect of gut microbiota on host function.

On the fiftieth anniversary. Postinfectious irritable bowel syndrome: mechanisms related to pathogens

BACKGROUND

Gastrointestinal (GI) infections resulting from bacterial, viral, and parasitic pathogens predispose to postinfectious irritable bowel syndrome (PI-IBS) and other functional GI disorders. Existing literature supports the role of enterochromaffin cell hyperplasia, serotonin synthesis and reuptake, impaired barrier function, altered immune activation, and potentially mast cell activation in the pathophysiology of PI-IBS.

PURPOSE

The objective of this review was to summarize from the literature the characteristics of the pathogens commonly implicated in PI-IBS, their acute enteritis phases, and the changes seen in the postinfectious phase that may contribute toward development of IBS. A limitation of our current understanding is that the postinfectious GI sequelae reported in prior studies followed epidemic diarrheal outbreaks often involving more than one pathogen, or the studies focused on highly selected, tertiary referral patients. Understanding the mechanisms, natural history, and optimized management of individuals suffering PI-IBS following the more typical sporadic infection requires larger studies of PI-IBS following GI infections encountered in community settings. These studies should include genetic, physiological, and molecular studies to provide more generalizable information that can ultimately be used to diagnose, manage, and potentially prevent the development of PI-IBS.

Next-generation sequencing for disorders of low and high bone mineral density

To achieve an efficient molecular diagnosis of osteogenesis imperfecta (OI), Ehlers-Danlos syndrome (EDS), and osteopetrosis (OPT), we designed a next-generation sequencing (NGS) platform to sequence 34 genes. We validated this platform on known cases and have successfully identified the causative mutation in most patients without a prior molecular diagnosis.

INTRODUCTION

Osteogenesis imperfecta, Ehlers-Danlos syndrome, and osteopetrosis are collectively common inherited skeletal diseases. Evaluation of subjects with these conditions often includes molecular testing which has important counseling and therapeutic and sometimes legal implications. Since several different genes have been implicated in these conditions, Sanger sequencing of each gene can be a prohibitively expensive and time-consuming way to reach a molecular diagnosis.

METHODS

In order to circumvent these problems, we have designed and tested a NGS platform that would allow simultaneous sequencing on a single diagnostic platform of different genes implicated in OI, OPT, EDS, and other inherited conditions, leading to low or high bone mineral density. We used a liquid-phase probe library that captures 602 exons (~100 kb) of 34 selected genes and have applied it to test clinical samples from patients with bone disorders.

RESULTS

NGS of the captured exons by Illumina HiSeq 2000 resulted in an average coverage of over 900X. The platform was successfully validated by identifying mutations in six patients with known mutations. Moreover, in four patients with OI or OPT without a prior molecular diagnosis, the assay was able to detect the causative mutations.

CONCLUSIONS

In conclusion, our NGS panel provides a fast and accurate method to arrive at a molecular diagnosis in most patients with inherited high or low bone mineral density disorders.

Endoscopic full-thickness biopsy of the gastric wall with defect closure by using an endoscopic suturing device: survival porcine study

BACKGROUND

The pathogenesis of several common gastric motility diseases and functional GI disorders remains essentially unexplained. Gastric wall biopsies that include the muscularis propria to evaluate the enteric nervous system, interstitial cells of Cajal, and immune cells can provide important insights for our understanding of the etiology of these disorders.

OBJECTIVES

To determine the technical feasibility, reproducibility, and safety of performing a full-thickness gastric biopsy (FTGB) by using a submucosal endoscopy with mucosal flap (SEMF) technique; the technical feasibility, reproducibility, and safety of tissue closure by using an endoscopic suturing device; the ability to identify myenteric ganglia in resected specimens; and the long-term safety.

DESIGN

Single center, preclinical survival study.

SETTING

Animal research laboratory, developmental endoscopy unit.

SUBJECTS

Twelve domestic pigs.

INTERVENTIONS

Animals underwent an SEMF procedure with gastric muscularis propria resection. The resultant offset mucosal entry site was closed by using an endoscopic suturing device. Animals were kept alive for 2 weeks.

MAIN OUTCOME MEASUREMENTS

The technical feasibility, reproducibility, and safety of the procedure; the clinical course of the animals; the histological and immunochemical evaluation of the resected specimen to determine whether myenteric ganglia were present in the sample.

RESULTS

FTGB was performed by using the SEMF technique in all 12 animals. The offset mucosal entry site was successfully closed by using the suturing device in all animals. The mean resected tissue specimen size was 11 mm. Mean total procedure time was 61 minutes with 2 to 4 interrupted sutures placed per animal. Histology showed muscularis propria and serosa, confirming full-thickness resections in all animals. Myenteric ganglia were visualized in 11 of 12 animals. The clinical course was uneventful. Repeat endoscopy and necropsy at 2 weeks showed absence of ulceration at both the mucosal entry sites and overlying the more distal muscularis propria resection sites. There was complete healing of the serosa in all animals with minimal single-band adhesions in 5 of 12 animals. Retained sutures were present in 10 of 12 animals.

LIMITATIONS

Animal experiment.

CONCLUSIONS

FTGB by using the SEMF technique and an endoscopic suturing device is technically feasible, reproducible, and safe. Larger tissue specimens will allow improved analysis of multiple cell types.

Rhabdomyosarcoma in middle ear of an adult: a rare presentation

Rhabdomyosarcoma of the middle ear is a rare tumor, even rarer in adults and has a very poor prognosis. We report here an unusual case of rhabdomyosarcoma in middle ear of an adult, mimicking chronic suppurative otitis media and facial nerve palsy.

Unusual metallic foreign bodies in the larynx: two case reports

Impaction of a foreign body (FB) in the larynx is a rare situation. It is more common in children then older age group. The authors report two cases of unusual foreign bodies in the larynx which presented with complaints of sudden onset of change of voice without any respiratory difficulty. One was of 9 y and other was a 7-y-old boy with foreign body in the glottis. In both cases there was accidental inhalation of the FB which was immediately followed by difficulty of speech. Metallic foreign bodies were removed successfully by direct laryngoscopy under general anesthesia (GA) which is followed by recovery of the symptoms.

What are the important subsets of gastroparesis?

Gastroparesis is often divided into subsets based on etiology and pathophysiology; however, the utility of these subsets in the diagnosis and treatment of gastro-paresis is not well defined. The objectives are to consider the subsets of gastroparesis from the perspectives of etiology and pathogenesis, pathophysiology, histopathology, and clinical associations, with particular focus on similarities and differences between diabetic and idiopathic gastroparesis and consideration of the potential subset of painful gastroparesis. We conclude that idiopathic and diabetic gastroparesis has similar initial presentations and manifestations, except that idiopathic gastroparesis tends to be associated more frequently with pain. Myopathic disorders are uncommon. Extrinsic denervation was considered the most common etiology; however, with the decline in surgery for peptic ulceration and in-depth study of full-thickness gastric biopsies, the most common intrinsic defects are being recognized in the interstitial cells of Cajal (ICC-opathy) and with immune infiltration and neuronal changes (intrinsic neuropathic gastroparesis). Histomorphological differences at the microscopic level between diabetic and idiopathic gastroparesis are still of unclear significance. Two gastroparesis subsets worthy of special mention, because they are potentially reversible with identification of the cause, are postviral gastroparesis, which has a generally good prognosis, and iatrogenic gastroparesis, especially in patients with non-surgical gastroparesis, such as diabetics exposed to incretins such as pramlintide and exenatide.

Clinical-histological associations in gastroparesis: results from the Gastroparesis Clinical Research Consortium

BACKGROUND

Cellular changes associated with diabetic (DG) and idiopathic gastroparesis (IG) have recently been described from patients enrolled in the Gastroparesis Clinical Research Consortium. The association of these cellular changes with gastroparesis symptoms and gastric emptying is unknown. The aim of this study was to relate cellular changes to symptoms and gastric emptying in patients with gastroparesis.

METHODS

Earlier, using full thickness gastric body biopsies from 20 DG, 20 IG, and 20 matched controls, we found decreased interstitial cells of Cajal (ICC) and enteric nerves and an increase in immune cells in both DG and IG. Here, demographic, symptoms [gastroparesis cardinal symptom index score (GCSI)], and gastric emptying were related to cellular alterations using Pearson's correlation coefficients.

KEY RESULTS

Interstitial cells of Cajal counts inversely correlated with 4 h gastric retention in DG but not in IG (r = -0.6, P = 0.008, DG, r = 0.2, P = 0.4, IG). There was also a significant correlation between loss of ICC and enteric nerves in DG but not in IG (r = 0.5, P = 0.03 for DG, r = 0.3, P = 0.16, IG). Idiopathic gastroparesis with a myenteric immune infiltrate scored higher on the average GCSI (3.6 ± 0.7 vs 2.7 ± 0.9, P = 0.05) and nausea score (3.8 ± 0.9 vs 2.6 ± 1.0, P = 0.02) as compared to those without an infiltrate.

CONCLUSIONS & INFERENCES

In DG, loss of ICC is associated with delayed gastric emptying. Interstitial cells of Cajal or enteric nerve loss did not correlate with symptom severity. Overall clinical severity and nausea in IG is associated with a myenteric immune infiltrate. Thus, full thickness gastric biopsies can help define specific cellular abnormalities in gastroparesis, some of which are associated with physiological and clinical characteristics of gastroparesis.

A randomized controlled trial of an Internet-based cognitive-behavioural skills package for carers of people with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) poses a major burden on families. Carers (e.g. parents or partners) of people with AN are often highly distressed and may inadvertently respond in ways that can contribute to the maintenance of the disorder, e.g. through high levels of over-involvement and criticism [also known as expressed emotion (EE)]. This study aimed to evaluate the efficacy of a novel web-based systemic cognitive-behavioural (CBT) intervention for carers of people with AN, designed to reduce carer distress and teach skills in how to offer effective support.

METHOD

Carers of people with AN (n=64) were randomly allocated to either the web-intervention, overcoming anorexia online, with limited clinician supportive guidance (by email or phone), or to ad-hoc usual support from the UK patient and carer organization Beat. Carer outcomes were assessed at post-treatment (4 months) and follow-up (6 months).

RESULTS

Compared with the control intervention, web-based treatment significantly reduced carers' anxiety and depression (primary outcome) at post-treatment, with a similar trend in carers' EE. Other secondary outcomes did not favour the online intervention. Gains were maintained at follow-up.

CONCLUSIONS

This is the first ever study to use an online CBT program to successfully reduce carer distress and improve carers' ability to support the person with AN.

Purification and transfection of cochlear Schwann cells

Schwann cells line nerve fibers in the peripheral nervous system (PNS) and synthesize myelin. In addition, they support neuronal survival, neurite growth and regeneration. In dissociated cultures of postnatal mouse spiral ganglia, regenerating neurites spontaneously associate with Schwann cells. However, the mechanisms and consequences of interactions between cochlear Schwann cells and spiral ganglion neurites have not been examined. Further, the similarities and differences between cochlear Schwann cells and other PNS Schwann cells have not been studied. Experiments to examine these questions will rely on the ability to purify and characterize cochlear Schwann cells. Here we present methods for purifying Schwann cells from postnatal mouse cochleas and for transfecting them with expression plasmids. Dissociated spiral ganglia were plated on poly-D-lysine/laminin in medium containing neurotrophins, leukemia inhibitory factor (LIF), N2 supplement and serum and maintained for 5 days. Cells were harvested with trypsin/EDTA and subjected to an immuno-magnetic purification procedure. After 24 h in vitro, cultures were >85% Schwann cells. Nucleofection of purified Schwann cells with pMax-green fluorescent protein (pMax-GFP) plasmid, or with pEGFP-C-vimentin plasmid returned >45% transfection efficiency. These methods will allow the in-depth characterization of cochlear Schwann cells and an evaluation of their biochemical, functional, and genetic mechanisms that may promote neurite growth from the spiral ganglion.

Maternal death due to extended spectrum beta-lactamase-producing E. coli: a warning for the future?

We describe a maternal death due to necrotising fasciitis caused by an extended spectrum beta-lactamase-producing Escherichia coli resistant to routinely used antimicrobial agents. Necrotising fasciitis is a rare complication of septicaemia with a high mortality. Signs of infection were insidious and masked by the use of routine analgesic agents and concurrent preeclampsia. The incidence of infection with extended spectrum beta-lactamase-producing organisms is increasing both in the United Kingdom and globally and will need to be considered in the obstetric setting. The use of the current Modified Early Warning Scores was of limited help in this case. Where there is no response to routine antibiotics within 12h, microbiological review is indicated.

Randomised controlled trial of CD-ROM-based cognitive-behavioural self-care for bulimia nervosa

BACKGROUND

Cognitive-behavioural self-care is advocated as a first step in the treatment of bulimia nervosa.

AIMS

To examine the effectiveness of a CD-ROM-based cognitive-behavioural intervention in bulimia nervosa and eating disorder not otherwise specified (NOS) (bulimic type) in a routine setting.

METHOD

Ninety-seven people with bulimia nervosa or eating disorder NOS were randomised to either CD-ROM without support for 3 months followed by a flexible number of therapist sessions or to a 3-month waiting list followed by 15 sessions of therapist cognitive-behavioural therapy (CBT) (ISRCTN51564819). Clinical symptoms were assessed at pre-treatment, 3 months and 7 months.

RESULTS

Only two-thirds of participants started treatment. Although there were significant group x time interactions for bingeing and vomiting, favouring the CD-ROM group at 3 months and the waiting-list group at 7 months, post hoc group comparisons at 3 and 7 months found no significant differences for bingeing or vomiting. CD-ROM-based delivery of this intervention, without support from a clinician, may not be the best way of exploiting its benefits.

Trends in colorectal day case surgery in NHS Trusts between 1998 and 2005

OBJECTIVE

Day case surgery is safe and offers potential benefits to both patients and healthcare providers. This study aimed to describe national changes in colorectal day case workload between 1998 and 2005.

METHODS

Admission data relating to Office of Population Censuses and Surveys Classification of Surgical Operations and Procedures (4th revision) (OPCS-4) coloproctology operation codes were analysed using the Hospital Episode Statistics (HES) database. Day case rates (DCRs) were calculated as the proportion of elective cases performed on an ambulatory basis.

RESULTS

In total, 3 119 058 colorectal admissions were recorded on the HES database between 1998 and 2005; 1 891 474 (61%) of these were for lower gastrointestinal endoscopies. Emergency cases accounted for 527 665 (17%), elective inpatient cases for 406 368 (13%) and elective day cases for 293 551 (9%) admissions. Throughout the study period the DCRs for five commonly performed elective colorectal procedures were: 0.70 for anal lesion excisions (OPCS-4 codes: H48.1, H48.2 and H48.3); 0.16 for haemorrhoidectomy (OPCS-4 code: H51.1); 0.63 for anal fissure procedures (OPCS-4 codes: H56.2 and H56.4); 0.39 for elective procedures for anal fistula (OPCS-4 codes: H55.1, H55.2, H55.3 and H55.4); 0.37 for elective pilonidal surgery (OPCS-4 codes: H59 and H60.2). Two emergency operations, drainage of perianal and pilonidal abscesses (OPCS-4 codes: H58.2 and H60.3 respectively), were identified as operations potentially amenable to day surgery. Over the seven study years, an annual average of 8559 (+/-SD 307) admissions were coded to drainage of a perianal abscess and 4676 (+/-SD 478) admissions to drainage of pilonidal abscess. The average annual bed usage associated with these procedures was 18 831 (+/-SD 718) and 7623 (+/-SD 436) bed days respectively.

CONCLUSIONS

Colorectal day case surgery is currently under-exploited in the NHS. By lifting some of the barriers to day case surgery significant resource savings may be possible.

Metal ion levels after metal-on-metal Ring total hip replacement: a 30-year follow-up study

Metal-on-metal bearings for total hip replacement (THR) are becoming increasingly popular. Improved wear characteristics mean that these articulations are being inserted into younger patients in the form of THR and resurfacing procedures. This has led to concerns regarding potential carcinogenicity because of the increased exposure to metal ions that the procedure brings. We have studied the serum cobalt and chromium concentrations in patients who had primary, well-fixed Ring metal-on-metal THRs for more than 30 years. The levels of cobalt and chromium were elevated by five and three times, respectively compared with those in our reference groups. Metal-on-metal articulations appear to be the source of metal ions throughout the life of the prosthesis. In three patients who had undergone revision of a previous metal-on-metal THR to a metal-on-polyethylene replacement the levels of metal ions were within the normal range. The elevations of cobalt and chromium ions seen in our study were comparable with those in patients with modern metal-on-metal THRs.

Culture conditions determine the prevalence of bipolar and monopolar neurons in cultures of dissociated spiral ganglion

To gain insight into the mechanisms that control the generation or maintenance of the characteristic bipolar morphology of cochlear spiral ganglion neurons, we have taken advantage of our recently developed procedure for culture of dissociated newborn mouse spiral ganglion. In these cultures, inclusion of the cytokine leukemia inhibitory factor (LIF) in the medium increases neuronal survival and the number of bipolar neurons. Here we tested effects of two other LIF-type cytokines (ciliary neurotrophic factor, CNTF; and human recombinant oncostatin M, hOSM) and of bone morphogenetic protein 4 (BMP4) on survival, morphology and neurite lengths of neurons in cultures of dissociated spiral ganglion. Like LIF, CNTF and hOSM increased neuronal survival and the number of surviving bipolar neurons. BMP4 also increased neuronal survival, but unlike LIF, CNTF and hOSM, increased the number of monopolar neurons and neurons with no neurites. In addition, population histograms demonstrate that the population lengths of the longer and shorter neurites of bipolar neurons were shorter in BMP4 containing cultures than in control or LIF cultures. When LIF and BMP4 were simultaneously added to the cultures, the BMP4 effects predominated. These experiments demonstrate that exposure to different environmental conditions can result in different morphologies in the surviving population of spiral ganglion neurons in culture.

Silent myocardial ischaemia and haemoglobin concentration: a randomized controlled trial of transfusion strategy in lower limb arthroplasty

BACKGROUND AND OBJECTIVES

Red cell transfusion is commonly used in orthopaedic surgery. Evidence suggests that a restrictive transfusion strategy may be safe for most patients. However, concern has been raised over the risks of anaemia in those with ischaemic cardiac disease. Perioperative silent myocardial ischaemia (SMI) has a relatively high incidence in the elderly population undergoing elective surgery. This study used Holter monitoring to compare the effect of a restrictive and a liberal red cell transfusion strategy on the incidence of SMI in patients without signs or symptoms of ischaemic heart disease who were undergoing lower limb arthroplasty.

MATERIALS AND METHODS

We performed a multicentre, controlled trial in which 260 patients undergoing elective hip and knee replacement surgery were enrolled and randomized to transfusion triggers that were either restrictive (8 g/dl) or liberal (10 g/dl). Participants were monitored with continuous ambulatory electrocardiogram (ECG) (Holter monitoring), preoperatively for 12 h and postoperatively for 72 h. The tapes were analysed for new ischaemia by technicians blinded to treatment. The total ischaemia time in minutes was divided by the recording time in hours and an ischaemic load in min/h was calculated. Haemoglobin levels were measured preoperatively, postoperatively in the recovery room, and on days one, three and five after surgery.

RESULTS

The mean postoperative haemoglobin concentration was 9.87 g/dl in the restrictive group and 11.09 g/dl in the liberal group. In the restrictive group, 34% were transfused a total of 89 red cell units, and in the liberal group 43% were given a total of 119 red cell units. A postoperative episode of silent ischaemia was experienced by 21/109 (19%) patients in the restrictive group and by 26/109 (24%) patients in the liberal group [mean difference -4.6%; 95% confidence interval (CI): -15.5% to 6%, P = 0.41). There was no significant difference (P = 0.53) between the overall ischaemic load in the restrictive group (median 0 min/h, range 0-4.18) and the liberal group (median 0 min/h, range 0-19.48). In those patients who did experience postoperative SMI, the mean ischaemic load was 0.48 min/h in the restrictive group and 1.51 min/h in the liberal group (ratio 0.32, 95% CI: 0.14-0.76, P = 0.011). The median postoperative length of hospital stay in the restrictive group was 7.3 days [range 5-11; interquartile range (IQR) 6-8] compared with 7.5 days (range 5-13; IQR 7-8) in the liberal group. The numbers were not large enough to conclude equivalence.

CONCLUSIONS

In patients without preoperative evidence of myocardial ischaemia undergoing elective hip and knee replacement surgery, a restrictive transfusion strategy seems unlikely to be associated with an increased incidence of SMI. A proportion of these patients experience moderate SMI, regardless of the transfusion trigger. Use of a restrictive transfusion strategy did not increase length of hospital stay, and use of this strategy would lead to a significant reduction in red cell transfusion in orthopaedic surgery. Our data did not indicate any potential for harm in employing such a strategy in patients with no prior evidence of cardiac ischaemia who were undergoing elective orthopaedic surgery.

Survival and morphology of auditory neurons in dissociated cultures of newborn mouse spiral ganglion

We have systematically characterized neuronal survival and growth in cultures derived from newborn/postnatal day 1 mouse cochlea. Dissociated cultures of the cochlear spiral ganglion provide an experimental environment in which to examine molecular mechanisms of survival, development and physiology of auditory neurons. To relate survival to the total number of neurons present in the source tissue, three cochleas from different newborn CD-1 mice were embedded in Araldite resin and serially sectioned at 5 mum thickness. All neurons were counted. To avoid overcounting, each section served as a lookup section for the next, giving 8240+/-423 (S.D.) neurons per ganglion. Cultures maintained in the presence of adjacent non-neural tissue, brain-derived neurotrophic factor, neurotrophin 3, leukemia inhibitory factor (LIF) and 10% fetal bovine serum returned the best overall survival (30%) at 42 h post-plating. Best overall survival required the continuous presence of a serum component(s) larger than 100,000 MW. Plating efficiency (number of neurons that attach to the well after 4 h) was similar in the presence or absence of LIF. Inclusion of LIF maintained 100% survival of plated neurons over 42 h of culture; without LIF, a large fraction of the neurons did not survive. LIF appeared to maintain survival by preferentially preserving a population of bipolar neurons, while having little effect on the number of monopolar neurons. This work provides quantitative measures of survival and morphology of auditory neurons in vitro. The results support the idea that survival of spiral ganglion neurons in vivo may depend on interactions with adjacent, non-neural tissue and raise the possibility that maintenance of bipolar morphology after hair cell damage may require biochemical mechanisms in addition to those induced by neurotrophins.

Oxoid aura system as a semi-automated, standard antimicrobial susceptibility test method

The need for a national strategy for antimicrobial resistance surveillance is well recognised. The diversity of susceptibility testing methods in the UK has led to the development of a standard method by the British Society for Antimicrobial Chemotherapy. Here, use of an early manual-measurement Oxoid Aura system is compared with an in-house, non-standard method. The usefulness of such a system in the evaluation of antibiotic susceptibility data collected for Staphylococcus aureus, including methicillin-resistant S. aureus, is also examined. An automated version of this equipment is now available.

Deception by applicants to family practice residencies

BACKGROUND AND OBJECTIVES

Our residency program experienced applicants who actively misrepresented qualifications, background, or abilities. The experiences of other family practice residencies were unknown. This study 1) determined what information family practice residency directors required from applicants, 2) assessed whether this information was confirmed or verified, and 3) describes the deceptive application information discovered by program directors.

METHODS

A questionnaire was sent to directors of all accredited family practice residencies. Information was collected about required information, data confirmation, and the deception and misrepresentation perceived.

RESULTS

Thirty-two percent of the directors responded. Eight of 13 items on the Electronic Residency Application System were designated as required by more than half of responding directors. Only two of the items (licensure and certain facts in the personal statement) were confirmed by a majority of directors who required them. Deception was recognized by nearly half of respondents within the past 5 years. Most cases involved specialty choice or the personal statement of candidates and were recognized during the interview or by direct confirmation of data.

CONCLUSIONS

Most directors appear to accept application information at face value. Recognition of deception about application information was reported. Misrepresentation by applicants may be a more common event than previously realized and may require more thorough verification of application credentials.

Analysis of the activity of promoters from two photosynthesis-related genes psaF and petH of spinach in a monocot plant, rice

The subunit III of photosystem I and ferredoxin-NADP(+)-oxidoreductase are encoded by nuclear genes, namely psaF and petH. The activity of their promoters from spinach has been evaluated in transgenic tobacco earlier. Evaluation of the activity of these Dicotyledoneae-specific promoters has been carried out in a monocot system (i.e. rice) by transient gene expression system, based on electroporation-mediated gene delivery into protoplasts from leaves and roots. It has been found that various promoter deletions show higher activity in leaf protoplasts and elements for quantitative response are widely distributed. Transgenic rice has also been produced with a petH promoter and gus reporter gene construct. Although petH promoter is a weak promoter in comparison to the 35S promoter, it expresses well in green tissues and could be useful for plant genetic engineering.

Isolation, characterization, and cloning of porcine complement component C7

Activation of the complement system through the classical, alternative, or lectin pathway results in the formation of the terminal complement complex. C7 plays an integral role in the assembly of this complex with target cell membranes. To date, only human C7 has been cloned and characterized; thus, in this study, we characterized the porcine complement component C7. Porcine C7 was isolated by affinity chromatography as a single glycoprotein with an approximate molecular mass of 90 kDa and 100 kDa under reducing and nonreducing conditions, respectively. The full-length porcine C7 cDNA was isolated, and the predicted amino acid sequence exhibited 80% identity with human C7 with conservation of the cysteine backbone and two putative N-linked glycosylation sites. Porcine C7 mRNA expression was detected in all tissues investigated, except polymorphonuclear and mononuclear leukocytes. Addition of purified porcine C7 restored the hemolytic activity of C7-depleted human sera in a dose-dependent manner. A functionally inhibitory mAb against porcine C7 attenuated the hemolytic activity of human, rabbit, or rat sera, suggesting an important conserved C7 epitope among species. These data demonstrate that porcine and human C7 are highly conserved, sharing structural and functional characteristics.

Spire contains actin binding domains and is related to ascidian posterior end mark-5

Spire is a maternal effect locus that affects both the dorsal-ventral and anterior-posterior axes of the Drosophila egg and embryo. It is required for localization of determinants within the developing oocyte to the posterior pole and to the dorsal anterior corner. During mid-oogenesis, spire mutants display premature microtubule-dependent cytoplasmic streaming, a phenotype that can be mimicked by pharmacological disruption of the actin cytoskeleton with cytochalasin D. Spire has been cloned by transposon tagging and is related to posterior end mark-5, a gene from sea squirts that encodes a posteriorly localized mRNA. Spire mRNA is not, however, localized to the posterior pole. SPIRE also contains two domains with similarity to the actin monomer-binding WH2 domain, and we demonstrate that SPIRE binds to actin in the interaction trap system and in vitro. In addition, SPIRE interacts with the rho family GTPases RHOA, RAC1 and CDC42 in the interaction trap system. Thus, our evidence supports the model that SPIRE links rho family signaling to the actin cytoskeleton.

Residency orientation: what we present and its effect on our residents

BACKGROUND AND OBJECTIVES

This study describes the content of family practice residency orientation programs, presents data about resident satisfaction with orientation, and determines if residents feel prepared for residency duties.

METHODS

We surveyed program directors and first-year residents at 100 family practice residency programs. We used questionnaires to collect data about orientation activities; program demographics; and resident characteristics, satisfaction, and preparation.

RESULTS

Sixty-nine percent of directors and 68% of their residents responded. The activity most frequently presented was a social event with faculty, while the least frequently presented was an assessment of cognitive knowledge. Even though residents desire orientation to clinical programs, and directors wish to promote group cohesion, the greatest number of orientation activities were presented to introduce hospital services and administration. Eighty-seven percent of residents were at least "somewhat satisfied," and 83% felt at least "somewhat prepared" for clinical duties after completing orientations. Residents from military programs were more likely not to be satisfied with their orientations. Extreme satisfaction was associated with residents in community-based programs. Being totally prepared was associated with having had prior graduate medical education.

CONCLUSIONS

While residents had previously reported having clinical needs from an orientation, the most frequently reported activities were nonclinical. Most residents reported having been satisfied with their orientations and having felt prepared for their new duties. Directors should consider increasing the clinical content of their orientations, including an assessment of residents' knowledge and clinical skills.

Nucleotide sequence of psbQ gene for 16-kDa protein of oxygen-evolving complex from Arabidopsis thaliana and regulation of its expression

The psbQ gene encoding a 16-kDa polypeptide of the oxygen-evolving complex of photosystem II has been isolated from Arabidopsis thaliana and characterized. The gene consists of a 28 nucleotide long leader sequence, two introns and three exons encoding a 223-amino-acid precursor polypeptide. The first 75 amino acids act as a transit peptide for the translocation of the polypeptide into the thylakoid lumen. Expression studies show that the gene is light-inducible and expresses only in green tissues with high steady-state mRNA levels in leaves. Using this gene as a probe, restriction fragment length polymorphism between two ecotypes, Columbia and Estland, has also been detected.

Right from the start: the family practice orientation study

BACKGROUND AND OBJECTIVES

Orientation to a residency program introduces residents to the essential functions of their duties, clarifies expectations, and acclimates them to a new social group. This study identified the orientation goals of family practice residency directors and compared those goals to the perceived needs of first-year family practice residents.

METHODS

We surveyed program directors and PGY-1 residents at 100 accredited family practice residency programs. Questionnaires obtained descriptive information about orientation programs and resident demographics and assessed directors' goals and residents' needs from orientations.

RESULTS

The orientation goal ranked most highly by directors was development of group cohesion. The need ranked most highly by residents was introduction to call duties and inpatient problems. Ranked responses of each group were not well associated.

CONCLUSIONS

The orientation goals of program directors and the reported orientation needs of residents were poorly associated. Most directors chose nonclinical areas as their most important goals for orientation. In contrast, most residents valued clinically related information during orientation to residency.

Lack of effect of erythromycin and ketoconazole on the pharmacokinetics and pharmacodynamics of steady-state intranasal levocabastine

The single-dose effects of the cytochrome P-450 inhibitors erythromycin and ketoconazole on the steady-state pharmacokinetics and electrocardiographic repolarization pharmacodynamics of intranasal levocabastine, a potent and selective H1-receptor antagonist, were evaluated in healthy young male subjects. Two randomized, open-label, placebo-controlled, two-way crossover studies were performed. Levocabastine nasal spray was administered as two sprays per nostril (0.05 mg/spray) twice daily (for a total daily dose of 0.4 mg) for 6 days. On Day 7, a single dose of 0.2 mg was administered followed immediately by a single dose of either oral placebo, erythromycin 333 mg, or ketoconazole 200 mg. In all treatment groups, levocabastine was rapidly absorbed, with peak plasma concentrations reached at approximately 3 hours in the erythromycin study and 2.8 hours in the ketoconazole study. The mean terminal half-life was approximately 45 and 44 hours, respectively. In both studies, mean steady-state plasma concentrations and pharmacokinetics of levocabastine following the single doses of erythromycin or ketoconazole were not significantly different from corresponding values seen with the concomitant administration of the placebo. No clinically significant mean changes from baseline in QT or QTc (QT corrected for heart rate) intervals occurred in any of the treatment groups, and none of the subjects in either study experienced abnormally prolonged QTc intervals. Intranasal levocabastine was well tolerated, with no difference in the incidence of adverse events between treatment groups in either study; adverse events were generally mild in severity. Since levocabastine undergoes only minimal hepatic metabolism and is not a substrate for or an inhibitor of cytochrome P-450, the likelihood of systemic drug interactions with drugs affecting the cytochrome P-450 system is minimal.

An outbreak of post-surgical wound infections due to Mycobacterium abscessus

An outbreak of post-operative wound infections due to Mycobacterium abscessus is described. During a 5-month period 45 post-surgical patients developed wound infection, manifested by wound breakdown, cellulitis, and discharge and progressing slowly to suppuration and sinus formation. The majority (43/45) had undergone out-patient operations, and 40 had had surgery in the inguinal region. The source of infection was identified as contaminated tap water. A study revealed serious deficiencies in the disinfection and sterilisation techniques employed in the operating theatre (OT), including major defects in the autoclaving machine. The outbreak was controlled after several specific measures were instituted. The patients responded well to treatment with conventional first-line anti-tuberculous drugs administered for 3-8 months. The report highlights the necessity of strict monitoring of disinfection and sterilisation techniques in surgical units and OTs.

Study of azathioprine encapsulation into liposomes

The factors influencing the encapsulation of azathioprine (AZA) into liposomes were investigated to find out the conditions for its optimal entrapment. Similar studies for comparison were also carried out on 6-mercaptopurine (6-MP), of which AZA is a prodrug. AZA and also 6-MP show higher encapsulation efficiencies in MLVs as compared to LUVs. Variation in phospholipid composition does not seem to affect the loading capacity of either of the two drugs. The encapsulation efficiency of both the drugs improves upon addition of cholesterol in the bilayer, but the effect is seen only up to 30% cholesterol. Thereafter the effect becomes constant. AZA shows better incorporation in the positively charged liposomes as compared to those with neutral or negative charge. The entrapment of 6-MP is, however, found to be independent of the charge on the liposomes. Entrapment efficiency for both the drugs markedly depends on the pH of the hydration medium, yielding better entrapment efficiencies at high pH values. The rise in solute concentration initially causes increase in the entrapment of the two drugs which is followed by a decreasing phase.

Stability-indicating analysis of isoxazolyl penicillins using dual wavelength high-performance liquid chromatography

Stability-indicating high-performance liquid chromatography analytical procedures were developed for specific determination of four isoxazolyl penicillins during degradation under neutral and accelerated acid/alkali conditions. The chromatographic conditions were set so that the drug peak was well separated from the peaks of the degradation products. Peak homogeneity of the resolving drug peak was assessed by the shape of the ratio chromatogram. Good and reproducible separations were achieved on a reversed-phase column using a mobile phase consisting of acetonitrile and a solution of 20 mM potassium dihydrogen phosphate plus 10 mM tetramethylammonium chloride in water (adjusted to pH 5). Optimal separations for all four drugs were achieved within the range of 15-21% organic modifier in the mobile phase. The detection wavelengths were 220 nm and 240 nm. The stability-indicating nature of the methods was confirmed by the linearity of the pseudo-first order plots. The utility of dual-wavelength chromatography in establishment of stability-indicating assays is highlighted.

The Stanmore total hip arthroplasty. A 15- to 20-year follow-up study

An ongoing study was made of 804 primary Stanmore total hip prostheses implanted in 839 patients between 1973 and 1991. The earliest surviving implants were brought back for radiologic and clinical review in 1995 at an average of 17 years after surgery. The remainder of the patients still living were sent a questionnaire to assess their current status. Survivorship was 95% at 10 years, 85% at 15 years, and 73% at 20 years. The average Merle d'Aubigné-Postel score was excellent up until 14 years. Patient satisfaction remained high until 22 years. Overall, 10% of the prostheses had failed. The results of this study suggest that the Stanmore prosthesis is capable of producing satisfactory long-term results that compare favorably with those of other cemented prostheses.

Effect of human milk prostaglandins and lactoferrin on respiratory syncytial virus and rotavirus

The effect of lactoferrin and prostaglandins E and F2 alpha on the growth of rotavirus and respiratory syncytial virus in cell culture was investigated. Lactoferrin inhibited the growth of respiratory syncytial virus at a concentration tenfold lower than that normally present in human milk. The prostaglandins had no effect on either virus growth, even at a concentration of 100-fold more than that found in human milk. Lactoferrin may have some antiviral properties in human milk in addition to its known antibacterial functions.

Rapid release and deactivation of plasminogen activators in human endothelial cell cultures in the presence of thrombin and ionophore A23187

alpha-Thrombin, DFP-thrombin, and ionophore A23187 induce the rapid release (less than 5 minutes) of a variety of proteins, including t-PA forms (Mr 110 and 70 k, after SDS-PAGE) from primary cultures, and both t-PA and u-PA (Mr 90 and 54 k) from subcultured human HUVECs. All PA activity forms are rapidly decreased in the releasates by some unknown mechanism. gamma-Thrombin does not induce the release of PAs from cultured HUVECs.