Stage based recipient and donor outcome in twin-to-twin transfusion syndrome treated by fetoscopic laser surgery using Solomon technique

OBJECTIVE

To evaluate twin survival stratified by Quintero stage in patients with twin-to-twin transfusion syndrome (TTTS) after Solomon laser treatment.

METHODS

Single center cohort of consecutive twin pregnancies treated with Solomon laser for TTTS. Preoperative Quintero stage, perioperative characteristics and obstetric factors were related to neonatal survival of the recipient and donor at discharge. Determinants of twin survival were evaluated using univariate, logistic regression and cumulative survival probability analyses.

RESULTS

Of 402 twins with TTTS, 80 (19.9%) had stage I, 126 (31.3%) stage II, 169 (42%) stage III and 27 (6.7%) stage IV. Post laser TAPS or recurrent TTTS occurred in 19 (4.7%) patients and 11 (2.7%) required repeat laser. Preterm premature rupture of membranes occurred in 150 (37.3%) patients and median gestational age of delivery 32+1 weeks. In 303 (75.4%) both twins were alive at discharge; [66 (82.5%) in stage I, 101 (80.2%) in stage II, 114 (67.5%) in stage III and 22 (81.5%) in stage IV, p=0.062]. Compared to recipients, donor survival was only lower in stage III (155 (91.7%) recipients vs 118 (69.8%) donors, Chi square 24.685, p<0.0001). Larger intertwin size discordance and umbilical artery (UA) end-diastolic velocity (EDV) determined donor demise (Nagelkerke R2 0.38, P<0.001). Overall, spontaneous post laser donor demise accounted for the majority (39.5%) of all losses. Cumulative donor survival decreased from 92% to 65% with size discordance >30% and 48% when UA EDV was absent (p<0.001).

CONCLUSION

Solomon laser achieves TTTS resolution and double survival in a high proportion of cases. Recipient and donor survival is comparable unless there is significant size discordance and placental dysfunction. This degree of unequal placental sharing, typically found in stage III, is the primary factor preventing double survival due to a higher rate of donor demise. This article is protected by copyright. All rights reserved.

The effect of horseshoes and surfaces on horse and jockey centre of mass displacements at gallop

Horseshoes influence how horses' hooves interact with different ground surfaces, during the impact, loading and push-off phases of a stride cycle. Consequently, they impact on the biomechanics of horses' proximal limb segments and upper body. By implication, different shoe and surface combinations could drive changes in the magnitude and stability of movement patterns in horse-jockey dyads. This study aimed to quantify centre of mass (COM) displacements in horse-jockey dyads galloping on turf and artificial tracks in four shoeing conditions: 1) aluminium; 2) barefoot; 3) GluShu; and 4) steel. Thirteen retired racehorses and two jockeys at the British Racing School were recruited for this intervention study. Tri-axial acceleration data were collected close to the COM for the horse (girth) and jockey (kidney-belt), using iPhones (Apple Inc.) equipped with an iOS app (SensorLog, sample rate = 50 Hz). Shoe-surface combinations were tested in a randomized order and horse-jockey pairings remained constant. Tri-axial acceleration data from gallop runs were filtered using bandpass Butterworth filters with cut-off frequencies of 15 Hz and 1 Hz, then integrated for displacement using Matlab. Peak displacement was assessed in both directions (positive 'maxima', negative 'minima') along the cranio-caudal (CC, positive = forwards), medio-lateral (ML, positive = right) and dorso-ventral (DV, positive = up) axes for all strides with frequency ≥2 Hz (mean = 2.06 Hz). Linear mixed-models determined whether surfaces, shoes or shoe-surface interactions (fixed factors) significantly affected the displacement patterns observed, with day, run and horse-jockey pairs included as random factors; significance was set at p<0.05. Data indicated that surface-type significantly affected peak COM displacements in all directions for the horse (p<0.0005) and for all directions (p≤0.008) but forwards in the jockey. The largest differences were observed in the DV-axis, with an additional 5.7 mm and 2.5 mm of downwards displacement for the horse and jockey, respectively, on the artificial surface. Shoeing condition significantly affected all displacement parameters except ML-axis minima for the horse (p≤0.007), and all displacement parameters for the jockey (p<0.0005). Absolute differences were again largest vertically, with notable similarities amongst displacements from barefoot and aluminium trials compared to GluShu and steel. Shoe-surface interactions affected all but CC-axis minima for the jockey (p≤0.002), but only the ML-axis minima and maxima and DV-axis maxima for the horse (p≤0.008). The results support the idea that hoof-surface interface interventions can significantly affect horse and jockey upper-body displacements. Greater sink of hooves on impact, combined with increased push-off during the propulsive phase, could explain the higher vertical displacements on the artificial track. Variations in distal limb mass associated with shoe-type may drive compensatory COM displacements to minimize the energetic cost of movement. The artificial surface and steel shoes provoked the least CC-axis movement of the jockey, so may promote greatest stability. However, differences between horse and jockey mean displacements indicated DV-axis and CC-axis offsets with compensatory increases and decreases, suggesting the dyad might operate within displacement limits to maintain stability. Further work is needed to relate COM displacements to hoof kinematics and to determine whether there is an optimum configuration of COM displacement to optimise performance and minimise injury.

Influence of Speed, Ground Surface and Shoeing Condition on Hoof Breakover Duration in Galloping Thoroughbred Racehorses

Simple Summary

In the stride cycle of a horse, there is a period of time when the hoof pushes off from the ground surface and rotates through an angle of approximately 90 degrees before it is lifted off. This time period is known as hoof breakover. Using slow-motion video footage, this study measured breakover duration in retired Thoroughbred racehorses galloping at a range of speeds on two surfaces (artificial and turf) in four shoeing conditions (aluminium, barefoot, GluShu and steel). Hooves from different limbs were assessed separately in this asymmetric gait. Increasing speed was correlated with decreasing breakover duration, and this trend was more enhanced in the hindlimbs than in the forelimbs at high gallop speeds. Breakover duration was faster on the artificial surface compared to the turf surface for all limbs, under the ground conditions studied. The first limb to contact the ground surface after the suspension phase (the ‘non-leading’ hindlimb), was additionally influenced by shoeing condition and an interaction that occurred between shoeing condition and speed. Determining parameters that alter breakover duration will be important for lowering the risk of musculo-skeletal injuries, optimising gait quality and improving performance in galloping racehorses during both training and racing.

Abstract

Understanding the effect of horseshoe–surface combinations on hoof kinematics at gallop is relevant for optimising performance and minimising injury in racehorse–jockey dyads. This intervention study assessed hoof breakover duration in Thoroughbred ex-racehorses from the British Racing School galloping on turf and artificial tracks in four shoeing conditions: aluminium, barefoot, aluminium–rubber composite (GluShu) and steel. Shoe–surface combinations were tested in a randomized order and horse–jockey pairings (n = 14) remained constant. High-speed video cameras (Sony DSC-RX100M5) filmed the hoof-ground interactions at 1000 frames per second. The time taken for a hoof marker wand fixed to the lateral hoof wall to rotate through an angle of 90 degrees during 384 breakover events was quantified using Tracker software. Data were collected for leading and non-leading forelimbs and hindlimbs, at gallop speeds ranging from 23–56 km h⁻¹. Linear mixed-models assessed whether speed, surface, shoeing condition and any interaction between these parameters (fixed factors) significantly affected breakover duration. Day and horse–jockey pair were included as random factors and speed was included as a covariate. The significance threshold was set at p < 0.05. For all limbs, breakover times decreased as gallop speed increased (p < 0.0005), although a greater relative reduction in breakover duration for hindlimbs was apparent beyond approximately 45 km h⁻¹. Breakover duration was longer on turf compared to the artificial surface (p ≤ 0.04). In the non-leading hindlimb only, breakover duration was affected by shoeing condition (p = 0.025) and an interaction between shoeing condition and speed (p = 0.023). This work demonstrates that speed, ground surface and shoeing condition are important factors influencing the galloping gait of the Thoroughbred racehorse.

Jockey Perception of Shoe and Surface Effects on Hoof-Ground Interactions and Implications for Safety in the Galloping Thoroughbred Racehorse

Riding racehorses is a high-risk profession and optimizing safety alongside performance is paramount. Horseshoes play a critical role in providing traction with the ground surface and are therefore a major determinant of safety. However, the subjective perceptions of expert riders influence attitudes towards using different shoes and must be taken into consideration before any changes may be implemented. This study used a questionnaire-based method to evaluate jockey opinion of four shoeing conditions (aluminum, steel, GluShu, and barefoot) trialed at gallop over turf and artificial surfaces. Nine Lickert-style questions explored impact, cushioning, responsiveness, grip, uniformity, smoothness of ride, safety, adaptation period, and overall rating for each shoe-surface combination. A total of 94 questionnaires, based on 15 horse-rider pairs, were assessed using descriptive statistics and linear mixed models performed in SPSS (P < .05). Data indicate that shoe type significantly affected all question responses, with the exception of impact. Surface-type significantly affected perception of grip and safety. Overall, jockeys showed a preference for aluminum and steel shoes across both artificial and turf tracks. These rated "excellent" and were considered to be "very supportive" in approximately 80% of trials, with a 100% "active" response, good grip, and a quick adaptation period. In contrast, barefoot and GluShu conditions were generally considered "moderately supportive," with barefoot appearing favorable on the artificial surface. On turf, barefoot was deemed the least smooth and the only condition that jockeys sometimes marked "unsafe" (17% of responses). Future work aims to investigate the relationship between jockey opinion and hoof kinematic data.

Testosterone treatment of men with mild cognitive impairment and low testosterone levels

INTRODUCTION

This study investigated the effects of testosterone (T) treatment on cognition, mood, and quality of life in men with mild cognitive impairment (MCI) and low serum T levels.

METHODS

A total of 351 community-dwelling men were screened, and 37 men evidenced both MCI and low T of whom 27 agreed for further screening. Twenty-two met all the study inclusion/exclusion criteria and enrolled in a 6-month randomized, double-blind, placebo-controlled study.

RESULTS

Total T levels significantly increased in the T treatment group. No significant changes were observed in measures of cognition, mood, or quality of life other than improvement in 1 objective measure of verbal memory (P < .05) and decreased depression symptoms (P < .02) in the treatment group.

CONCLUSIONS

Testosterone treatment may modestly improve verbal memory and depression symptoms in men with both MCI and low T.

Amyloid precursor protein (APP) processing genes and cerebrospinal fluid APP cleavage product levels in Alzheimer's disease

The aim of this exploratory investigation was to determine if genetic variation within amyloid precursor protein (APP) or its processing enzymes correlates with APP cleavage product levels: APPα, APPβ or Aβ42, in cerebrospinal fluid (CSF) of cognitively normal subjects or Alzheimer's disease (AD) patients. Cognitively normal control subjects (n = 170) and AD patients (n = 92) were genotyped for 19 putative regulatory tagging SNPs within 9 genes (APP, ADAM10, BACE1, BACE2, PSEN1, PSEN2, PEN2, NCSTN and APH1B) involved in the APP processing pathway. SNP genotypes were tested for their association with CSF APPα, APPβ, and Aβ42, AD risk and age-at-onset while taking into account age, gender, race and APOE ε4. After adjusting for multiple comparisons, a significant association was found between ADAM10 SNP rs514049 and APPα levels. In controls, the rs514049 CC genotype had higher APPα levels than the CA, AA collapsed genotype, whereas the opposite effect was seen in AD patients. These results suggest that genetic variation within ADAM10, an APP processing gene, influences CSF APPα levels in an AD specific manner.

CDIO and the Liverpool Constructionarium

The Constructionarium initiative can be classified as the implement section of the conceive, design, implement, operate (CDIO) innovative educational framework for civil engineering students. CDIO is an international learning and teaching initiative which is based on the principle of embedding active learning into engineering education at all levels. The Constructionarium provides a practical construction experience for various civil engineering structures such as a gravity concrete oil rig, a cable-stayed steel bridge, a transmission tower, a subway entrance hall and a clay core dam, all at a reduced scale. Students are required to follow the same professional and health and safety procedures that a construction contractor follows on a real construction project. A collaborating construction contractor and a design consultant offer close supervision, support and guidance for all site activities, typically covering preparation of method statements, risk assessments, construction planning, costing, setting-out, use of construction tools, and so on. The Constructionarium is a concentrated learning week for students for which there is no other equivalent replacement activity. In this paper, the Liverpool Constructionarium is presented in detail, including pre-Constructionarium preparation, learning objectives, running projects, associated problems and learning outcomes. In addition the results from pre- and post-Constructionarium questionnaires are presented to show measurement of learning outcomes from student feedback.

Effect of zinc supplementation on respiratory tract infections in children with cystic fibrosis

Zinc (Zn) has significant anti-oxidant and anti-inflammatory activity. Zn deficiency can occur in subsets of patients with cystic fibrosis (CF) especially those with malabsorption and impaired growth. Although supplemental Zn has significantly reduced infections in various disorders, its efficacy has not been thoroughly investigated in CF. We performed a double blind placebo controlled pilot study to investigate the effect of daily 30 mg elemental Zn for 1 year on the rate of respiratory tract infections (RTIs), use of antibiotics and plasma cytokines in 26 children with CF (ages 7-18 years). Plasma Zn, Cu, inflammatory cytokines and ex vivo generation of IL-2 were measured at baseline and at the end of the study. The number of days of oral antibiotics was lower in Zn treated patients compared to placebo (P = 0.05). However, compared to placebo, the effect of Zn was greater in patients who exhibited low plasma Zn at baseline (P = 0.02) than those who had plasma Zn levels identical to normal subjects (P = 0.55). Zn supplementation was marginally effective in reducing percentage increase in plasma IL-6 and IL-8 while increasing the percentage change in ex vivo generation of IL-2 in isolated mononuclear cell. In conclusion, oral intake of 30 mg/day of Zn reduced the number of days of oral antibiotics used to treat RTIs in children with CF. A higher daily Zn dose may be needed to decrease RTIs and modify immune responses.

Conditional expression of a Gi-coupled receptor in osteoblasts results in trabecular osteopenia

G protein-coupled receptors (GPCRs) coupled to activation of Gs, such as the PTH1 receptor (PTH1R), have long been known to regulate skeletal function and homeostasis. However, the role of GPCRs coupled to other G proteins such as Gi is not well established. We used the tet-off system to regulate the expression of an activated Gi-coupled GPCR (Ro1) in osteoblasts in vivo. Skeletal phenotypes were assessed in mice expressing Ro1 from conception, from late stages of embryogenesis, and after weaning. Long bones were assessed histologically and by microcomputed tomography. Expression of Ro1 from conception resulted in neonatal lethality that was associated with reduced bone mineralization. Expression of Ro1 starting at late embryogenesis resulted in a severe trabecular bone deficit at 12 wk of age (>51% reduction in trabecular bone volume fraction in the proximal tibia compared with sex-matched control littermates; n = 11; P < 0.01). Ro1 expression for 8 wk beginning at 4 wk of age resulted in a more than 20% reduction in trabecular bone volume fraction compared with sex-matched control littermates (n = 16; P < 0.01). Bone histomorphometry revealed that Ro1 expression is associated with reduced rates of bone formation and mineral apposition without a significant change in osteoblast or osteoclast surface. Our results indicate that signaling by a Gi-coupled GPCR in osteoblasts leads to osteopenia resulting from a reduction in trabecular bone formation. The severity of the phenotype is related to the timing and duration of Ro1 expression during growth and development. The skeletal phenotype in Ro1 mice bears some similarity to that produced by knockout of Gs-alpha expression in osteoblasts and thus may be due at least in part to Gi-mediated inhibition of adenylyl cyclase.

Off flavours in large waterbodies: physics, chemistry and biology in synchrony

The Laurentian Great Lakes of North America are a drinking water source for millions of Canadian and US consumers. These waterbodies have undergone extensive change over the past century as a result of widespread degradation and remediation. Many of the Lakes are prone to taste and odour (T&O), and although these outbreaks have been poorly monitored, evidence suggests that they are increasing in frequency. Tracing and controlling T&O in such large systems presents a challenging task, due to their physical size and complexity. This paper presents an overview of recent investigative and management approaches to T&O in Lake Ontario and its outflow, the St. Lawrence River. We have identified three distinct patterns of T&O in these source-waters, caused by geosmin and 2-methylisoborneol and differing in their planktonic and benthic sources, and temporal and spatial dynamics. Each pattern has required a different approach by scientists and management, in partnership with the water industry. We have shown these T&O outbreaks are caused and moderated by physical, chemical and biological mechanisms over a spectrum of spatial and temporal scales. Canadian municipalities affected by these outbreaks have been key to the investigation of the links between T&O and ecosystem processes with the aim to develop more proactive water treatment and long-term management.

Ablation of atrial fibrillation in the rapid pacing canine model using a multi-electrode loop catheter

OBJECTIVES

This investigation details our experience using a loop catheter to ablate atrial fibrillation (AF) in dogs.

BACKGROUND

Atrial fibrillation is the most common arrhythmia and has significant morbidity. Maintenance of normal sinus rhythm (NSR) after conversion in many patients is still a challenge.

METHODS

A multi-electrode loop catheter was used to create linear atrial lesions to ablate AF in a rapid atrial pacing model in 29 dogs. Rhythm status was assessed over a six-month recovery period, after which tissue analysis was performed.

RESULTS

Acute conversion to NSR or atrial tachycardia (AT) was achieved in 90% of cases. Six of 26 conversions occurred after only left atrial (LA) lesions, and two after just right atrial lesions. Sixteen (62%) of 26 lesions that resulted in AF conversion were in the LA, and 11 of these 16 conversions occurred during a lesion connecting the mitral ring to the pulmonary veins. Acute conversion rate was similar with ring and coil electrodes, but AT was more frequent with coil electrodes (63% vs. 31%). At six months 80% of dogs were in NSR, 14% were in AT, and 7% remained in AF. There was an average reduction in P-wave amplitude of 64 +/- 26% after power application. Tissue analysis revealed transmural contiguous lesions when final outcome was NSR, and nontransmural/noncontiguous lesions where AF persisted.

CONCLUSIONS

Multi-electrode loop catheters can create contiguous transmural lesions in either atrium to safely and effectively ablate AF and provide a stable long-term rhythm outcome in this dog model. The left atrium appears to be the dominant chamber that sustains AF. Atrial tachycardia is a frequent acute outcome with coil electrodes.

Time course of left atrial mechanical recovery after linear lesions: normal sinus rhythm versus a chronic atrial fibrillation dog model

INTRODUCTION

The extent of left atrial (LA) mechanical function recovery after creation of linear lesions using the loop catheter has not been determined.

METHODS AND RESULTS

LA mechanical function was assessed before and after linear lesions using transthoracic two-dimensional and Doppler echocardiography in two groups: (1) normal, which consisted of eight healthy dogs in normal sinus rhythm (NSR); and (2) atrial fibrillation (AF), which consisted of nine dogs in spontaneous AF for 6 months following rapid pacing-induced AF. NSR was restored with linear lesions in all AF dogs. All animals were in NSR 5 months after linear lesions. In the normal dogs, the maximal velocity of the transmitral flow "A" wave was reduced by 42% during the first week postablation and by 24% at 5 months versus preablation. At 5 months, no differences in LA function were noted between the normal and the AF group for all measured Doppler parameters. At 5 months, the LA systolic area in AF dogs was reduced by 40% (preablation 12.9 +/- 2.9 cm2, postablation 7.6 +/- 1.2 cm2; P < 0.01) and in the normal dogs by 21% (preablation 10.0 +/- 0.9 cm2, postablation 7.8 +/- 1.2 cm2; P < 0.02), being the same in both groups within 3 months of recovery.

CONCLUSION

The creation of linear lesions with the loop catheter does not result in LA expansion. In normal dogs, LA mechanical activity is reduced for 3 weeks postablation. The time course of LA mechanical function recovery is the same for the AF and the NSR dogs, and it is complete at 3 months postablation. At 5 months, LA systolic function parameters in both groups are reduced by 24% versus the preablation values of the normal dogs. Linear lesions result in a significant reduction in LA size.

Sulfides impair short chain fatty acid beta-oxidation at acyl-CoA dehydrogenase level in colonocytes: implications for ulcerative colitis

The disease process of ulcerative colitis (UC) is associated with a block in beta-oxidation of short chain fatty acid in colonic epithelial cells which can be reproduced by exposure of cells to sulfides. The aim of the current work was to assess the level in the beta-oxidation pathway at which sulfides might be inhibitory in human colonocytes. Isolated human colonocytes from cases without colitis (n = 12) were exposed to sulfide (1.5 mM) in the presence or absence of exogenous CoA and ATP. Short chain acyl-CoA esters were measured by a high performance liquid chromatographic assay. 14CO2 generation was measured from [1-14C]butyrate and [6-14C]glucose. 14CO2 from butyrate was significantly reduced (p < 0.001) by sulfide. When colonocytes were incubated with hydrogen sulfide in the presence of CoA and ATP, butyryl-CoA concentration was increased (p < 0.01), while crotonyl-CoA (p < 0.01) and acetyl-CoA (p < 0.01) concentrations were decreased. These results show that sulfides inhibit short chain acyl-CoA dehydrogenase. As oxidation of n-butyrate governs the epithelial barrier function of colonocytes the functional activity of short chain acyl-CoA dehydrogenase may be critical in maintaining colonic mucosal integrity. Maintaining the functional activity of dehydrogenases could be an important determinant in the expression of ulcerative colitis.

Colonic luminal hydrogen sulfide is not elevated in ulcerative colitis

It has been proposed that the reduction in n-butyrate oxidation by colonic epithelial cells observed in ulcerative colitis may be related to exposure to reduced forms of sulfur derived from dissimilatory sulfate reduction by luminal microflora. This study aims to compare stool sulfide concentrations in control and colitic subjects. Control subjects had significant colorectal disease excluded by virtue of their selection. Patients with ulcerative colitis were stratified by disease extent and activity, and by salicylate drug use. Stool sulfide was measured using a direct spectrophotometric method on NaOH (free sulfide) and zinc acetate (total sulfide) stool slurries. Fifteen control and 19 colitic subjects were studied. There was no significant difference in stool sulfide between control and colitic patients (free sulfide, control = 0.52 (0.17), colitic = 0.45 (0.10), t = 0.36, P = 0.71, total sulfide, control = 1.33 (0.21), colitic = 0.96 (0.15), t = 1.44, P = 0.16). Disease extent or activity did not significantly influence stool sulfide. These results do not support a primary etiologic role for luminal sulfide in ulcerative colitis.

Effect of sulphide on short chain acyl-CoA metabolism in rat colonocytes

BACKGROUND

It has been proposed that the diminished n-butyrate oxidation observed in ulcerative colitis may be the result of sulphide induced inhibition of short chain acyl-coenzyme A (acyl-CoA) dehydrogenase activity.

AIM

To examine the acyl-CoA ester profiles in isolated rat colonic epithelial cells treated in vitro with sodium hydrogen sulphide (NaHS).

METHODS

Isolated rat colonic epithelial cell suspensions were incubated for 10 minutes in the presence of [1-14C] n-butyrate (5 mM), with and without NaHS (1.5 mM). Incubations were carried out both in the presence and the absence of exogenous CoA and ATP. Metabolic performance was assessed by 14CO2 production and by acyl-CoA ester production measured by HPLC with ultraviolet detection.

RESULTS

Results are given as mean (SEM). For colonocytes incubated in the presence of exogenous CoA and ATP, treatment with NaHS significantly diminished 14CO2 production (control 0.97 (0.06) mumol/g dry weight cells/min, treated 0.26 (0.09) mumol/g dry weight cells/min, p = 0.0019), was associated with an increase in butyryl-CoA concentrations in the final reaction mixture at 10 minutes (control 2.55 (0.28) mumol/g dry weight cells, treated 3.32 (0.32) mumol/g dry weight cells, p = 0.002), and a reduction in crotonyl-CoA concentrations (control 0.274 (0.02) mumol/g dry weight cells, treated 0.120 (0.04) mumol/g dry weight cells, p = 0.008). The mean concentration of acetyl-CoA in the reaction mixture at 10 minutes was not significantly different between control and sulphide treated incubations. There were no significant differences in acyl-CoA ester profiles observed when cells were incubated in the absence of exogenous CoA and ATP.

CONCLUSIONS

These results support the view that sulphides inhibit n-butyrate oxidation in colonic epithelial cells by inhibiting short chain acyl dehydrogenation of activated fatty acids.

Hydrogen sulphide produces diminished fatty acid oxidation in the rat colon in vivo: implications for ulcerative colitis

BACKGROUND

Several lines of evidence suggest a possible role for reduced forms of sulphur (including sulphide) in ulcerative colitis. The aims of this study were to assess the metabolic profile of colonic epithelial cells after treatment in vivo with hydrogen sulphide and correlate this with mucosal histological appearances.

METHODS

Adult Sprague-Dawley rats had antegrade Roux-en-Y colostomies fashioned to allow access to the 'in-flow' bowel. Animals were treated with 2 mL sodium hydrosulphide (10, 20, 30 mmol/L) or saline control twice daily via the stoma for four (acute experiments) and 90 (chronic experiments) days. Isolated colonic epithelial cell suspensions prepared from such animals were incubated in the presence of [1-14C]-labelled n-butyrate (5 mmol/L) or [6-14C]glucose (5 mmol/L). Metabolic performance was measured radiometrically (14CO2 production) and enzymatically (ketone body production and lactogenesis). The histological appearances of treated mucosa were scored for acute inflammatory changes.

RESULTS

There was a highly significant reduction in 14CO2 production from both n-butyrate and glucose in all groups compared to the control in both acute and chronic experiments. There was no difference between groups with respect to histological appearance and no evidence of acute inflammation in any specimen.

CONCLUSIONS

Sodium hydrosulphide impairs rat colonic epithelial metabolic performance in vivo, but does not produce mucosal inflammation.

Methionine derivatives diminish sulphide damage to colonocytes--implications for ulcerative colitis

BACKGROUND

Bacterial production of anionic sulphide is increased in the colon of ulcerative colitis and sulphides can cause metabolic damage to colonocytes.

AIMS

To assess the reversal of the damaging effect of sulphide to isolated colonocytes by methionine and methionine derivatives.

METHODS AND SUBJECTS

Isolated colonocytes were prepared from rat colons and 12 human colectomy specimens. In cell suspensions 14CO2/acetoacetate generation was measured from [1-14C]-butyrate (5.0 mmol/l) in the presence of 0-2.0 mmol/l sodium hydrogen sulphide. The effect of 5.0 mmol/l L-methionine, S-adenosylmethionine 1,4 butane disulphonate and DL-methionine-S-methylsulphonium chloride on sulphide inhibited oxidation was observed.

RESULTS

In rat colonocytes sodium hydrogen sulphide dose dependently reduced oxidative metabolite formation from n-butyrate, an action reversed in order of efficacy by S-adenosylmethionine 1,4 butane disulphonate > DLmethionine-S-methyl-sulphonium chloride > L-methionine. In human colonocytes S-adenosylmethionine 1,4 butane disulphonate most significantly improved 14CO2 production (p = < 0.005) suppressed by sodium hydrogen sulphide.

CONCLUSION

Sulphide toxicity in colonocytes is reversible by methyl donors. The efficiency of sulphide detoxification may be an important factor in the pathogenesis and treatment of ulcerative colitis for which S-adenosylmethionine 1,4 butane disulphonate may be of therapeutic value.

Fc gamma RIIA alleles are heritable risk factors for lupus nephritis in African Americans

Allelic variants of Fc gamma R confer distinct phagocytic capacities providing a mechanism for heritable susceptibility to immune complex disease. Human Fc gamma RIIa has two codominantly expressed alleles, R131 and H131, which differ substantially in their ability to ligate human IgG2. The Fc gamma RIIa-H131 is the only human Fc gamma R which recognizes IgG2 efficiently and optimal IgG2 handling occurs only in the homozygous state. Therefore, since immune complex clearance is essential in SLE, we hypothesized that Fc gamma RIIA genes are important disease susceptibility factors for SLE, particularly lupus nephritis. In a two-stage cross-sectional study, we compared the distribution of Fc gamma RIIA alleles in African Americans with SLE to that in African American non-SLE controls. A pilot study of 43 SLE patients and 39 controls demonstrated a skewed distribution of Fc gamma RIIA alleles, with only 9% of SLE patients homozygous for Fc gamma RIIa-H131 compared with 36% of controls (odds ratio, 0.18; 95% CI, 0.05-0.69, P = 0.009). This was confirmed with a multicenter study of 214 SLE patients and 100 non-SLE controls. The altered distribution of Fc gamma RIIA alleles was most striking in lupus nephritis. Trend analysis of the genotype distribution showed a highly significant decrease in Fc gamma RIIA-H131 as the likelihood for lupus nephritis increased (P = 0.0004) consistent with a protective effect of the Fc gamma RIIA-H131 gene. The skewing in the distribution of Fc gamma RIIA alleles identifies this gene as a risk factor with pathophysiologic importance for the SLE diathesis in African Americans.

Selective inhibition of fatty acid oxidation in colonocytes by ibuprofen: a cause of colitis?

Ibuprofen is associated with initiation or exacerbation of ulcerative colitis. As ibuprofen selectively inhibited fatty acid oxidation in the liver or caused mitochondrial damage in intestinal cells, its effect on substrate oxidation by isolated colonocytes of man and rat was examined. Ibuprofen dose dependently (2.0-7.5 mmol/l) and selectively inhibited 14CO2 production from labelled n-butyrate in colonocytes from the proximal and distal human colon (n = 12, p = < 0.001). Glucose oxidation was either unaltered or increased. Because short chain fatty acid oxidation is the main source of acetyl-CoA for long chain fatty acid synthesis, the inhibition of prostaglandin synthesis by ibuprofen in the colonic mucosa could also occur at this level. Because the concentrations of ibuprofen that can be attained in the human colon are not known, conclusions drawn from current dosages are tentative. The inhibition of fatty acid oxidation by ibuprofen may be biochemically implicated in the initiation and exacerbation of ulcerative colitis, manifestation of which would depend on the ibuprofen concentrations reached in the colon.

Sulphide impairment of substrate oxidation in rat colonocytes: a biochemical basis for ulcerative colitis?

1. Isolated colonic epithelial cells of the rat were incubated for 40 min with [6-14C]glucose and n-[1-14C]butyrate in the presence of 0.1-2.0 mmol/l NaHS, a concentration range found in the human colon. Metabolic products, 14CO2, acetoacetate, beta-hydroxybutyrate and lactate, were measured and injury to cells was judged by diminished production of metabolites. 2. Oxidation of n-butyrate to CO2 and acetoacetate was reduced at 0.1 and 0.5 mmol/l NaHS, whereas glucose oxidation remained unimpaired. At 1.0-2.0 mmol/l NaHS, n-butyrate and glucose oxidation were dose-dependently reduced at the same rate. 3. To bypass short-chain acyl-CoA dehydrogenase activity necessary for butyrate oxidation, ketogenesis from crotonate was measured in the presence of 1.0 mmol/l NaHS. Suppression by sulphide of ketogenesis from crotonate (-10.5 +/- 6.1%) compared with control conditions was not significant, whereas suppression of ketogenesis from n-butyrate (-36.00 +/- 5.14%) was significant (P = < 0.01). Inhibition of FAD-linked oxidation was more affected by NaHS than was NAD-linked oxidation. 4. L-Methionine (5.0 mmol/l) significantly redressed the impaired beta-oxidation induced by NaHS. Methionine equally improved CO2 and ketone body production, suggesting a global reversal of the action of sulphide. 5. Sulphide-induced oxidative changes closely mirror the impairment of beta-oxidation observed in colonocytes of patients with ulcerative colitis. A hypothesis for the disease process of ulcerative colitis is that sulphides may form persulphides with butyryl-CoA, which would inhibit cellular short-chain acyl-CoA deHydrogenase and beta-oxidation to induce an energy-deficiency state in colonocytes and mucosal inflammation.

Reducing sulfur compounds of the colon impair colonocyte nutrition: implications for ulcerative colitis

BACKGROUND

Mercaptides (sodium hydrogen sulfide and sodium methanethiol) and mercapto-fatty acid (sodium mercaptoacetate) are reducing agents that help to maintain anaerobic conditions in the colonic lumen. The metabolic effect of these agents on n-butyrate and glucose oxidation in human colonocytes is unknown.

METHODS

Isolated human colonocytes were prepared from 31 colectomy specimens, and generation of oxidative metabolites from [1-14C]n-butyrate and [6-14C]glucose was measured in the presence and absence of reducing agents. Injury to cells was judged by diminished production of metabolites.

RESULTS

The injurious action of mercaptides at all sites of the colon was of the order of sodium hydrogen sulfide > methanethiol > mercaptoacetate. Significant inhibition of n-butyrate (< 0.005) but not glucose oxidation was observed with sodium hydrogen sulfide in the ascending colon, splenic flexure, and rectosigmoid region. Hydrogen sulfide more significantly inhibited fatty acid oxidation in the rectosigmoid than in the ascending colon (P < 0.02).

CONCLUSIONS

Metabolic effects of sodium hydrogen sulfide on butyrate oxidation along the length of the colon closely mirror metabolic abnormalities observed in active ulcerative colitis, and the increased production of sulfide in ulcerative colitis suggests that the action of mercaptides may be involved in the genesis of ulcerative colitis.

Lipogenesis from n-butyrate in colonocytes. Action of reducing agent and 5-aminosalicylic acid with relevance to ulcerative colitis

Cell membranes of colonic epithelial cells (CEC) in ulcerative colitis show structural abnormalities which are specific to the disease and which suggest impaired lipogenesis in CECs. Lipogenesis from [1-14C]-n-butyrate, the chief oxidative fuel of colonic epithelial cells, was measured in isolated CECs under control conditions, with or without glucose and in the presence of mercaptoacetate, a major reducing agent in the colonic lumen. Glucose significantly (p < 0.01) stimulated lipogenesis from [1-14C]-butyrate which was reversed by 5 mM mercaptoacetate. Mercaptoacetate significantly diminished CEC thiolase activity (EC 2.3.1.9). 5-Aminosalicylic acid reversed the adverse effects of mercaptoacetate in the saponifiable fraction of extracted lipids. Changes in lipogenesis due to colonic luminal reducing agents would affect the barrier function of CECs a feature relevant to the disease process of ulcerative colitis.

Speech and language characteristics of genetic syndromes

A series of tables is presented as a diagnostic aid for the clinician when presented with a client who has a genetic syndrome. Information is provided on physical features, inheritance pattern, incidence rate, speech and language characteristics, and references. The speech and language clinician is cautioned that there is great variation of expression in genetic syndromes. However, the tables can be used to find those characteristics identified in the literature as manifested in a particular genetic syndrome.

Radiation dose to critical organs of staff and patients during neuroradiology

The doses delivered to some critical organs of patients and staff during cerebral angiography, X-ray computer assisted tomographic scanning and 99Tcm brain scanning have been measured or assessed. The results show that doses received by staff and by the patients' gonads are generally quite low. However, patients having two or more of the investigations could receive skin and orbit doses in excess of 25 rad.

Multiple forms of elongation factor 1 from calf brain

Heavy and light forms of elongation factor 1 (EF-1) from calf brain have been partially purified. The heterogeneous heavy species (EF-1(H)) with molecular weights of 2.5 x 10(5) to over 1 x 10(6) appears to be a complex or aggregate of the light form of the enzyme (EF-1(L)); the latter has a molecular weight of between 50,000 and 60,000. EF-1(H) but not EF-1(L), contains significant amounts of free and esterified cholesterol. Although EF-1(H) and EF-1(L) are both active in aminoacyl-tRNA binding to ribosomes, EF-1(L) reacts with GTP and aminoacyl-tRNA more efficiently than EF-1(H).