A study to assess smoking habits and smoking exposure in sportspeople

BACKGROUND

Tobacco smoking is a leading public health concern and is the most preventable cause of morbidity and mortality worldwide. Sportspeople are no exception and those who smoke are predisposed to the same hazardous health effects as the general public, in addition to the potential effects it may have on their sporting performance.

AIM

We aimed to ascertain the prevalence of tobacco consumption in a sporting population. We also endeavoured to quantify the use of electronic cigarettes (e-cigarettes) and assess exposure to passive smoking.

DESIGN

Observational study.

METHODS

A web-based e-questionnaire was distributed to participants from various sports across Ireland between November 2017 and January 2018, and data were analysed using SPSS.

RESULTS

A total of 546 sportspeople completed the survey with more than twice as many male respondents. Of whom, 16% of participants were current smokers, with males significantly more likely to smoke (P < 0.001), 26% of rugby players were current smokers which was significantly higher when compared with other sports (P < 0.01), 10% of all participants were exposed to second-hand smoke for more than 1 h per day and 2% of all participants were current users of e-cigarettes.

CONCLUSION

The prevalence of smoking in our study population was higher than other literature reports. Further studies are essential to evaluate the potential negative effects this may be having on sporting performance, career progression and indeed injury occurrence/rehabilitation. It is imperative to address the matter of smoking in athletes, not only for public health concerns but also considering they are important role models in our society.

Non-invasive assessment of ventriculo-arterial coupling using aortic wave intensity analysis combining central blood pressure and phase-contrast cardiovascular magnetic resonance

BACKGROUND

Wave intensity analysis (WIA) in the aorta offers important clinical and mechanistic insight into ventriculo-arterial coupling, but is difficult to measure non-invasively. We performed WIA by combining standard cardiovascular magnetic resonance (CMR) flow-velocity and non-invasive central blood pressure (cBP) waveforms.

METHODS AND RESULTS

Two hundred and six healthy volunteers (age range 21-73 years, 47% male) underwent sequential phase contrast CMR (Siemens Aera 1.5 T, 1.97 × 1.77 mm2, 9.2 ms temporal resolution) and supra-systolic oscillometric cBP measurement (200 Hz). Velocity (U) and central pressure (P) waveforms were aligned using the waveform foot, and local wave speed was calculated both from the PU-loop (c) and the sum of squares method (cSS). These were compared with CMR transit time derived aortic arch pulse wave velocity (PWVtt). Associations were examined using multivariable regression. The peak intensity of the initial compression wave, backward compression wave, and forward decompression wave were 69.5 ± 28, -6.6 ± 4.2, and 6.2 ± 2.5 × 104 W/m2/cycle2, respectively; reflection index was 0.10 ± 0.06. PWVtt correlated with c or cSS (r = 0.60 and 0.68, respectively, P < 0.01 for both). Increasing age decade and female sex were independently associated with decreased forward compression wave (-8.6 and -20.7 W/m2/cycle2, respectively, P < 0.01) and greater wave reflection index (0.02 and 0.03, respectively, P < 0.001).

CONCLUSION

This novel non-invasive technique permits straightforward measurement of wave intensity at scale. Local wave speed showed good agreement with PWVtt, and correlation was stronger using the cSS than the PU-loop. Ageing and female sex were associated with poorer ventriculo-arterial coupling in healthy individuals.

AS-amyloidosis. Dual pathology or novel disease? A multimodality, multi-centre assessment across health and disease

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

onbehalf

AS-Amyloidosis consortium

Background

The coexistence of severe aortic stenosis (lone AS) and transthyretin cardiac amyloidosis (lone amyloidosis) is common, but the resultant AS-amyloidosis phenotype is unclear.

Purpose

We characterised AS-amyloidosis, hypothesizing that the dual insult of AS-amyloidosis results is a severe phenotype.

Methods

We compared four cohorts with deep phenotyping: 81 older age controls, 359 lone AS, 36 AS-amyloidosis (Perugini grade 2 and 3) and 107 lone amyloidosis (Perugini grade 2 and 3).

Results

AS-amyloidosis was similar to lone AS with respect to left ventricular mass and LVEF (57 (45, 64)%). It was similar to lone amyloidosis with respect to lateral S" (0.04 (0.03, 0.06) m/s), NT-proBNP (4149 (1449, 6459) ng/L) and troponin T (56 (34, 100) ng/L). Whilst, prevalence of carpal tunnel syndrome (CTS) (17%) and diastolic function (E/A ratio 1.1 (0.8, 2.8)) were intermediate.

Conclusion

AS-amyloidosis is not a double insult from AS and amyloidosis, but a mixed phenotype with features similar to lone amyloidosis (cardiac biomarkers), lone AS (remodelling and LVEF) or intermediate (diastology and CTS).

Characteristics across all 4 groups Variable Older age controls (n = 81) Lone AS (n = 359) AS-amyloidosis (n = 36) Lone amyloidosis (n = 107) P value Age (years) 82 (80, 84)*†‡ 85 (80, 88)§∞ 88 (85, 92)# 80 (75, 84) &lt;0.005 Sex (% male) 69 *‡ 49 ∞ 61 # 94 &lt;0.005 Carpal tunnel syndrome (%) 0 2 § 17 # 38 &lt;0.005 Voltage/mass ratio 0.22 (0.14, 0.27)‡ 0.18 (0.13, 0.28)∞ 0.18 (0.09, 0.21)# 0.07 (0.05, 0.10) &lt;0.005 NT-ProBNP (ng/L) 131 (66, 221)*†‡ 1629 (639, 3941)§∞ 4149 (1449, 6459) 2888 (1755, 5483) &lt;0.005 hsTnT (ng/L) 12 (8, 17)*†‡ 24 (15, 40)§∞ 56 (34, 100) 62 (41, 82) &lt;0.005 Inferolateral wall thickness (cm) 0.9 (0.8, 1.0)*†‡ 1.1 (0.9, 1.3)∞ 1.3 (1.1, 1.5)# 1.7 (1.6, 1.9) &lt;0.005 Anteroseptal wall thickness (cm) 1.0 (0.9, 1.2)*†‡ 1.4 (1.2, 1.6)§∞ 1.5 (1.3, 1.8) 1.7 (1.6, 1.9) &lt;0.005 Indexed LV mass (g/m2) 79 (66, 102)*†‡ 128 (99, 152)∞ 126 (116, 140)# 174 (159, 200) &lt;0.005 LVEF (%) 59 (54, 63)‡ 59 (50, 65)∞ 57 (45, 64)# 39 (31, 48) &lt;0.005 Lateral S" (m/s) 0.08 (0.07, 0.09)*†‡ 0.07 (0.05, 0.08)§∞ 0.05 (0.04, 0.07) 0.05 (0.04, 0.06) &lt;0.005 Septal S" (m/s) 0.06 (0.06, 0.08)*†‡ 0.05 (0.04, 0.06)∞ 0.04 (0.03, 0.06) 0.04 (0.03, 0.05) &lt;0.005 E/A 0.7 (0.6, 0.8)*†‡ 0.8 (0.7, 1.3)§∞ 1.1 (0.8, 2.8)# 2.4 (1.8, 3.3) &lt;0.005 RV Wall thickness (cm) 0.4 (0.3, 0.4)*†‡ 0.4 (0.4, 0.6)∞ 0.6 (0.4, 0.7)# 0.8 (0.7, 1.0) &lt;0.005 TAPSE (cm) 2.4 (2.0, 2.7)*†‡ 2.1 (1.6, 2.5)∞ 1.9 (1.5, 2.1)# 1.4 (1.2, 1.9) &lt;0.005 Classical LFLG AS (%) 9 13 0.472 * p &lt; 0.05, Old age control vs Lone AS † p &lt; 0.05, Old age control vs AS-amyloidosis ‡ p &lt; 0.05, Old age control vs Lone amyloidosis § p &lt; 0.05, Lone AS vs AS-amyloidosis ∞ p &lt; 0.05, Lone AS vs Lone amyloidosis # p &lt; 0.05, AS-amyloidosis vs Lone amyloidosis Abstract Figure. AS-amyloidosis compared to other cohorts

Pulsatile and resistive systolic loads as determinants of left ventricular remodelling after physical training

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): British Heart Foundation Barts Cardiovascular Biomedical Research Centre

onbehalf

The Marathon Study Consortium

Introduction

Cardiovascular function depends on the inter-relation between heart and vasculature.  The contribution of aorta and peripheral vessels to the total systolic load of the left ventricle (LV) can be represented respectively by a "pulsatile" and a "resistive" component. We sought to understand their interrelation by exploring how LV remodelling occurred with altered load associated with an external stimulus (training). Methods: 237 untrained healthy male and female subjects volunteering for their first-time marathon were recruited. At baseline and after 6 months of unsupervised training, race completers underwent 1.5T cardiac magnetic resonance, brachial and non-invasive central blood pressure assessment. For analysis, runners were divided into 4 groups according to the variation (positive versus null or negative) in Total Arterial Compliance Index (TACi), representing the pulsatile component of the LV load, and in Systemic Vascular Resistance Index (SVRI), representing the resistive component of the LV load. Results: 138runners (age 21-69 years; F: 51%) completed the race. Data are reported for each variable as Δ mean [95% Confidence Interval]. In the whole cohort, training was associated with a small increase in LV mass index (+3g/m2, [0, 6 g/m2]), indexed LV end-diastolic volume (EDVi) (+3ml/m2, [-2, 5 3ml/m2]), in LV mass/LVEDV ratio (+0.02g/ml, [0.00, 0.04 g/ml]) and in TACi (+0.02ml/m2, [0.02, 0.38 ml/m2]). SVRi mildly fell (-43dyn·s/cm2[-103, 17dyn·s/cm2]). TACi increase was associated with LVEDVi increase and no change in LV mass/EDV (eccentric remodelling). On the other hand, both TACi reduction and SVRi increase were associated with increase in LV mass/EDV and no significant change in LVEDVi (concentric remodelling). A similar increase in LV mass was observed in all groups. See Table. Conclusion: Cardiac remodelling observed after mild, medium term, unsupervised training seems to be related to the modifications of aorta and peripheral vessels. In particular, a reduction in pulsatile load seems associated with eccentric LV remodelling, while an increase in both pulsatile and resistive with concentric LV remodelling. Further research is needed to understand the interaction between TACi and SVRi.

Table 1 LV EDVi (ml/m2) LV mass index (g/m2) LV mass/EDV TACi increase (n = 75) +4 [0, 9] +3 [0, 7] 0 [-0.03, 0.03] TACi decrease (n = 62) -1 [-6, 4] +3 [0, 8] 0.04 [0.01, 0.07] SVRi increase (n = 63) 0 [-4,4] +3 [0, 7] +0.03 [0, 0.06] SVRi decrease (n = 73) +3 [-3, 7] +3 [-1, 6] +0.01 [-0.02, 0.04]

Myocardial fibrosis quantification by cardiac CT predicts outcome in severe aortic stenosis

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Background

Myocardial extracellular volume (ECV) increases with fibrosis, oedema or infiltration. ECV by CMR predicts all-cause and cardiovascular mortality in severe AS after valve intervention. Previous studies have shown that ECV can be reliably quantified by computed tomography (ECVCT), but these studies have not differentiated between ECV elevation due to fibrosis or cardiac amyloid deposition (13-16% of patients with severe AS). 

Purpose

We hypothesised that ECVCT quantification, performed as part of a transcatheter aortic valve implantation (TAVI) work-up CT, predicts survival in patients with severe AS without cardiac amyloid (lone AS).

Methods

Patients aged ≥75, with severe AS, referred for TAVI at Barts Heart Centre (as part of ATTRact-AS (NCT03029026)) underwent CT as part of their clinical work-up. All patients had 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD) scintigraphy and those with a positive result were excluded.  CT was performed on a 128-slice dual-source 3rdgeneration scanner (Siemens Somatom FORCE) and ECVCT was acquired during the TAVI work-up CT using additional pre- and 3-minute post-contrast ‘axial shuttle mode’ acquisitions (no additional contrast).  ECVCT was calculated from the Hounsfield units (HU) and a venous haematocrit (HCT): ECVCT = (1-HCT) x (ΔHUmyo/ΔHUblood).

Results

Following exclusion of 16 patients with cardiac uptake on DPD, 93 patients (41% male, aged 85 ± 5 years) were included in the study.  All patients had severe AS (AV Vmax 4.12 ± 0.63m/s, mean AV gradient 42 ± 14mmHg, AVA 0.71 ± 0.23cm2). The mean HCT was 0.38 ± 0.04 and total dose-length product for additional research scans was 364 ± 41 mGy.cm. 76 patients (82%) underwent TAVI. ECVCT was 32 ± 3% in the entire cohort, which we then split into those with a ‘higher’ ECVCT (&gt;34%, n = 23, representing the highest quartile) and those with a ‘lower’ ECVCT (≤34%, n = 70, representing the lower quartiles). Over a median follow-up of 25 months (IQR 17-34 months) there were 27 deaths (29%), of whom 11 did not undergo TAVI (41%). There were 10 deaths in the 23 patients (44%) with a higher ECVCT, compared to 17 in the 70 patients (24%) with a lower ECVCT (p = 0.03, figure 1). This mortality difference remained significant when those patients who did not undergo TAVI were excluded (p = 0.03).

Conclusions

Myocardial fibrosis quantified by ECVCT is associated with a significantly worse prognosis in lone AS, even after patients with AS-amyloid are excluded. ECVCT can be performed as a simple addition to the TAVI work-up CT and provides additional prognostic information.

Abstract Figure.

Automated analysis of single cells using Laser Tweezers Raman Spectroscopy

In recent years, significant progress has been made into the label-free detection and discrimination of individual cancer cells using Laser Tweezers Raman Spectroscopy (LTRS). However, the majority of examples reported have involved manual trapping of cells, which is time consuming and may lead to different cell lines being analysed in discrete batches. A simple, low-cost microfluidic flow chamber is introduced which allows single cells to be optically trapped and analysed in an automated fashion, greatly reducing the level of operator input required. Two implementations of the flow chamber are discussed here; a basic single-channel device in which the fluid velocity is controlled manually, and a dual-channel device which permits the automated capture and analysis of multiple cell lines with no operator input. Results are presented for the discrimination of live epithelial prostate cells and lymphocytes, together with a consideration of the consequences of traditional 'batch analysis' typically used for LTRS of live cells.

Car Safety Seat Usage and Selection Among Families Attending University Hospital Limerick

The safest way for children to travel within a car is by provision of a weight-appropriate safety-seat. To investigate this, we conducted a cross-sectional study of adult parents who had children under 12 years, and collected information related to: car use, safety-seat legislation, and type of safety-seat employed. Data were reviewed on 120 children from 60 respondents. Ninety-eight (81.7%) children were transported daily by car. Forty-eight (81.4%) respondents were aware that current safety-seat legislation is based on the weight of the child. One hundred and seven (89.9%) children were restrained during travel using a car safety-seat. One hundred and two (96.2%) safety seats were newly purchased, installed in 82.3% (88) cases by family members with installation instructions fully read in 58 (55.2%) cases. Ninety-nine (83.2%) children were restrained using an appropriate safety-seat for their weight. The results show that four out of five families are employing the most appropriate safety-seat for their child, so providing an effective mechanism to reduce car-related injury. However, the majority of safety-seats are installed by family members, which may have child safety consequences.

The Establishment of a Pilot Paediatric Obesity Clinic at the University Hospital, Limerick

This study describes the establishment of a pilot Paediatric Obesity Clinic (POC) in the University Hospital Limerick (UHL). Referrals were received from consultant paediatricians in the catchment areas of UHL for paediatric patients with high levels of excess adiposity. Fifteen patients and their families were invited to the POC in 2012. An initial medical assessment was conducted by 2 consultant paediatricians. Patients were also reviewed by a dietitian, a physiotherapist and physical activity experts from local Sports Partnerships. Twelve children and their families attended the POC (mean age = 8.08 years; Range = 3.6-13.6): 11/12 were overweight and 9/12 were obese. Abnormalities in blood work were detected as follows: 1/7 had elevated LDL-cholesterol; 2/8 had elevated triglyceride levels; 4/8 had elevated fasting insulin; 2/8 had elevated fasting glucose. With the current prevalence of obesity in paediatric populations, initiatives such as UHL's POC need to be established, funded and supported, to try to meet complex, multidisciplinary patient needs and to prevent future complex and expensive health complications.

Disturbance of the gut microbiota in early-life selectively affects visceral pain in adulthood without impacting cognitive or anxiety-related behaviors in male rats

Disruption of bacterial colonization during the early postnatal period is increasingly being linked to adverse health outcomes. Indeed, there is a growing appreciation that the gut microbiota plays a role in neurodevelopment. However, there is a paucity of information on the consequences of early-life manipulations of the gut microbiota on behavior. To this end we administered an antibiotic (vancomycin) from postnatal days 4-13 to male rat pups and assessed behavioral and physiological measures across all aspects of the brain-gut axis. In addition, we sought to confirm and expand the effects of early-life antibiotic treatment using a different antibiotic strategy (a cocktail of pimaricin, bacitracin, neomycin; orally) during the same time period in both female and male rat pups. Vancomycin significantly altered the microbiota, which was restored to control levels by 8 weeks of age. Notably, vancomycin-treated animals displayed visceral hypersensitivity in adulthood without any significant effect on anxiety responses as assessed in the elevated plus maze or open field tests. Moreover, cognitive performance in the Morris water maze was not affected by early-life dysbiosis. Immune and stress-related physiological responses were equally unaffected. The early-life antibiotic-induced visceral hypersensitivity was also observed in male rats given the antibiotic cocktail. Both treatments did not alter visceral pain perception in female rats. Changes in visceral pain perception in males were paralleled by distinct decreases in the transient receptor potential cation channel subfamily V member 1, the α-2A adrenergic receptor and cholecystokinin B receptor. In conclusion, a temporary disruption of the gut microbiota in early-life results in very specific and long-lasting changes in visceral sensitivity in male rats, a hallmark of stress-related functional disorders of the brain-gut axis such as irritable bowel disorder.

Food and beverage advertising during children's television programming

BACKGROUND

Increasing prevalence of overweight and obese children in developed countries poses a substantial threat to long-term health. One well-described factor is the amount of time spent watching television, with exposure to food advertising a known influence on food preferences and consumption patterns.

AIMS

Following recent formulation of new rules regarding advertising of food during children's programming, we sought to examine the advertising content in children-specific television broadcasts on Irish television.

METHODS

Advertisement content analysis for 5 weekdays of children-specific television broadcasting from 0700 to 1700 hours on Irish television was performed. Data were coded and transferred to SPSS for analyses. Food and beverage advertisements were coded based on type of product, nutritional content, intended age group and outcome.

RESULTS

322 advertisements were broadcast during the recording period. 31 % (n = 101) of advertisements related to food or beverage products with 66.3 % (n = 68) of food advertisements being for foods that should be eaten in moderation. The most frequently recorded food advertisement was for fast food products (27.3 %, n = 24), followed by sweets/candy (21.6 %, n = 19) and dairy products (17.0 %, n = 15). The most frequently recorded beverage advertisement was for natural orange juices (46.2 %, n = 6). 54.7 % (n = 176) of advertisements were adult specific with 27.3 % (n = 88) being children specific. All food and beverage advertisements were associated with a positive outcome (n = 322).

CONCLUSIONS

These results demonstrate that food and beverages depicted in advertisements during children's programming are predominantly unhealthy foods with high salt and sugar contents. The findings from this study again highlight the ongoing need for new rules regarding food advertising in children's programming.

The relationship between intact PTH and biointact PTH (1-84) with bone and mineral metabolism in pre-dialysis chronic kidney disease (CKD)

OBJECTIVES

Abnormalities in PTH are implicated in the pathogenesis of bone abnormalities in chronic kidney disease (CKD)-mineral bone disorder (CKD-MBD). PTH concentrations are important in clinical decision and management. This emphasises the importance of providing an assay which measures biologically active PTH. We compared concentrations of intact PTH with biointact PTH (1-84) in CKD and end stage renal disease (ESRD) and investigated the relationship between the 2 PTH assays with bone and mineral laboratory parameters and bone mineral density (BMD) in CKD.

DESIGN AND METHODS

We assessed 140 patients (61 in ESRD and 79 with CKD stages 1-4) in this cross-sectional study. We measured biointact PTH (1-84) as well as routine biochemical parameters on all subjects. In the CKD cohort, bone turnover markers; bone alkaline phosphatase (BAP) and tartrate resistant acid phosphatase (TRACP)-5b and bone mineral density (BMD) were also determined.

RESULTS

In ESRD, intact PTH concentration was significantly higher compared to biointact PTH (1-84) (422 [443] v/s 266 [251] pg/mL, (p<0.001) with an average bias of 60%. In CKD, intact PTH concentration was also higher compared to biointact PTH (1-84) (79[55] v/s 68[49] pg/mL p<0.001) with an average bias of 18%. Only the biointact PTH (1-84) assay showed any significant correlation with serum calcium concentrations (r=-0.26, p<0.05) and phosphate (r=0.25, p<0.05) in CKD. Following multilinear regression analysis and adjustment for all significant co-variables, only eGFR, BAP and 25 (OH)vitamin remained significantly associated with intact PTH and biointact PTH (1-84). The strength of association was stronger between BAP and biointact PTH (1-84) (biointact PTH (1-84): p=0.007, intact PTH: p=0.01). In adjusted analyses, only biointact PTH (1-84) was significantly associated with BMD at the fore-arm (FARM) (p=0.049).

CONCLUSIONS

The study confirms the differences between intact PTH and biointact PTH (1-84) in ESRD. Whilst there may be similarities in the diagnostic ability of both intact and biointact PTH (1-84), our data suggest that biointact PTH (1-84) assay may better reflect bone metabolism and BMD in CKD. Further longitudinal studies are needed.

The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner

Bacterial colonisation of the intestine has a major role in the post-natal development and maturation of the immune and endocrine systems. These processes are key factors underpinning central nervous system (CNS) signalling. Regulation of the microbiome-gut-brain axis is essential for maintaining homeostasis, including that of the CNS. However, there is a paucity of data pertaining to the influence of microbiome on the serotonergic system. Germ-free (GF) animals represent an effective preclinical tool to investigate such phenomena. Here we show that male GF animals have a significant elevation in the hippocampal concentration of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid, its main metabolite, compared with conventionally colonised control animals. Moreover, this alteration is sex specific in contrast with the immunological and neuroendocrine effects which are evident in both sexes. Concentrations of tryptophan, the precursor of serotonin, are increased in the plasma of male GF animals, suggesting a humoral route through which the microbiota can influence CNS serotonergic neurotransmission. Interestingly, colonisation of the GF animals post weaning is insufficient to reverse the CNS neurochemical consequences in adulthood of an absent microbiota in early life despite the peripheral availability of tryptophan being restored to baseline values. In addition, reduced anxiety in GF animals is also normalised following restoration of the intestinal microbiota. These results demonstrate that CNS neurotransmission can be profoundly disturbed by the absence of a normal gut microbiota and that this aberrant neurochemical, but not behavioural, profile is resistant to restoration of a normal gut flora in later life.

Kynurenine pathway in psychosis: evidence of increased tryptophan degradation

The kynurenine pathway of tryptophan degradation may serve to integrate disparate abnormalities heretofore identified in research aiming to elucidate the complex aetiopathogenesis of psychotic disorders. Post-mortem brain tissue studies have reported elevated kynurenine and kynurenic acid in the frontal cortex and upregulation of the first step of the pathway in the anterior cingulate cortex of individuals with schizophrenia. In this study, we examined kynurenine pathway activity by measuring tryptophan breakdown, a number of pathway metabolites and interferon gamma (IFN-gamma), which is the preferential activator of the first-step enzyme, indoleamine dioxygenase (IDO), in the plasma of patients with major psychotic disorder. Plasma tryptophan, kynurenine pathway metabolites were measured using high-performance liquid chromatography (HPLC) in 34 patients with a diagnosis on the psychotic spectrum (schizophrenia or schizoaffective disorder) and in 36 healthy control subjects. IFN-gamma was measured using enzyme-linked immunosorbent assay (ELISA). The mean tryptophan breakdown index (kynurenine/tryptophan) was significantly higher in the patient group compared with controls (P < 0.05). IFN-gamma measures did not differ between groups (P = 0.23). No relationship was found between measures of psychopathology, symptom severity and activity in the first step in the pathway. A modest correlation was established between the tryptophan breakdown index and illness duration. These results provide evidence for kynurenine pathway upregulation, specifically involving the first enzymatic step, in patients with major psychotic disorder. Increased tryptophan degradation in psychoses may have potential consequences for the treatment of these disorders by informing the development of novel therapeutic compounds.

Tryptophan catabolism in females with irritable bowel syndrome: relationship to interferon-gamma, severity of symptoms and psychiatric co-morbidity

Irritable bowel syndrome (IBS) has been linked with abnormal serotonin functioning and immune activation. Tryptophan forms the substrate for serotonin biosynthesis, but it can alternatively be catabolized to kynurenine (Kyn) by the enzyme indoleamine 2,3-dioxygenase (IDO), the main inducer of which is interferon-gamma. The primary aim of this study was to test the hypothesis that IBS is associated with increased tryptophan (Trp) catabolism along the Kyn pathway due to increased IFN-gamma levels. Plasma Kyn, Trp and IFN-gamma levels were measured in 41 female IBS subjects and 33 controls. Indoleamine 2,3-dioxygenase activity was assessed using the Kyn to Trp ratio. Psychiatric co-morbidity was assessed using the Patient Health Questionnaire, and severity of IBS assessed using self-report ordinal scales. Irritable bowel syndrome subjects had increased Kyn concentrations compared with controls (P = 0.039) and there was a trend for Kyn:Trp to be increased in the IBS group (P = 0.09). There was a positive correlation between IBS severity and Kyn:Trp (r = 0.57, P < 0.001). Those with severe IBS symptoms had increased Kyn:Trp (P < 0.005) compared to those with less severe symptoms and controls, and were over twice as likely to have depression or anxiety compared to those with less severe IBS (RR = 2.2, 95% CI 1.2-3.9). No difference in IFN-gamma levels was observed between groups; however, IFN-gamma was positively correlated with Kyn:Trp in IBS (r = 0.58, P = 0.005) but not controls (r = 0.12, P = 0.5). Females with IBS have abnormal Trp catabolism. The Kyn:Trp is related to symptom severity, and those with severe IBS symptoms have increased shunting of Trp along the Kyn pathway which contributes to the abnormal serotonergic functioning in this syndrome.

Evidence for association and epistasis at the DAOA/G30 and D-amino acid oxidase loci in an Irish schizophrenia sample

The D-amino acid oxidase (DAO) signaling pathway has been implicated in schizophrenia pathogenesis. This may be mediated through modulation of NMDA function by DAO, which is in turn activated by DAO activator (DAOA, formerly G72). Chumakov et al. (2002); PNAS 99: 13675-13680, identifying the novel schizophrenia susceptibility gene DAOA/G30 and a number of independent studies have since reported evidence of association between the DAOA and DAO genes and schizophrenia. However, at least two studies have failed to replicate the epistatic interaction between these loci described in the original report and there have been differences in the associated alleles/haplotypes reported at each locus. In this study, we performed association and epistasis analyses of the DAOA/G30 and DAO loci in a sample of 373 cases with DSM-IV schizophrenia/schizoaffective disorder and 812 controls from the Republic of Ireland. Corrected for the number of tests performed, we found evidence for association between markers at both genes and schizophrenia: DAOA/G30 (P = 0.005, OR = 1.34 (1.09, 1.65)) and DAO (P = 0.003, OR = 1.43 (1.12, 1.84). The data suggest that evidence for association at DAO (marker rs2111902) is more consistent than previously realized, particularly in Caucasian schizophrenia populations. We identified evidence for epistatic interaction between the associated SNPs at DAOA and DAO genes in contributing to schizophrenia risk (OR = 9.3 (1.4, 60.5). Based on these data, more systematic investigation of genes involved in DAO signaling is required.

A novel luminescent lifetime-based optrode for the detection of gaseous and dissolved oxygen utilising a mixed ormosil matrix containing ruthenium (4,7-diphenyl-1,10-phenanthroline)3Cl2 (Ru.dpp)

A novel luminescent lifetime optrode is presented for the detection of gaseous and dissolved oxygen. The optrode utilises ruthenium (4,7-diphenyl-1,10-phenanthroline)(3)Cl(2) as the sensing fluorophore immobilised in a hydrophobic ormosil matrix. The ormosil matrix is synthesised at room temperature from octyltriethoxysilane and methyltriethoxysilane precursors. Investigations of different ormosils were conducted and the most effective one was selected for optrode production. Optrodes were tested for responses to gaseous and dissolved oxygen. Their responses were modelled using traditional two-site or two-exponential methods and feed-forward artificial neural networks. Comparison of the two modelling methodologies is presented and further improvements in modelling and ormosil design are suggested.

Confirmation and refinement of an 'at-risk' haplotype for schizophrenia suggests the EST cluster, Hs.97362, as a potential susceptibility gene at the Neuregulin-1 locus

Two recent association studies have implicated the neuregulin-1 gene (NRG1) at chromosome 8p21-22 as a susceptibility gene for schizophrenia. Stefansson et al identified three 'at-risk' haplotypes (HapA, B and C) which spanned the NRG1 locus and shared a common core haplotype. Subsequently, they demonstrated evidence that the core haplotype was associated with schizophrenia in an independent Scottish sample. To confirm and refine this haplotype we investigated the NRG1 locus in an independent Irish case-control sample. We did not find the core haplotype to be associated in our sample. However, we identified a refined 2-marker haplotype (HapB(IRE)) that shared common alleles with one of the Icelandic 'at-risk' haplotypes and is in significant excess in the Irish cases (19.4%) vs controls (12.3%) (P=0.013). This refined 'at-risk' haplotype is also in significant excess in the Scottish case sample (17.0% vs 13.5%; P=0.036). Interestingly, this refined 'at-risk' haplotype is positioned close to an EST cluster of unknown function (Hs.97362) within intron 1 of NRG1.

A practical guide to capacity assessment and patient consent in Hong Kong

A person's decision-making capacity is pivotal when a doctor determines whether a person has the ability to make his or her own decisions, and thus it has major clinical, ethical, and legal significance, especially in Hong Kong, where the Mental Health Ordinance has introduced Guardianship provisions and provisions for the treatment of mentally incapacitated persons. This paper examines the legal concept of decision-making capacity and its clinical assessment within the local context. It is important for doctors to be aware of the legal mechanisms under which both urgent and non-urgent treatment can be given to mentally incapacitated persons, provided that the treatment is necessary and given in the best interests of the patient.

Early cerebro-craniofacial dysmorphogenesis in schizophrenia: a lifetime trajectory model from neurodevelopmental basis to 'neuroprogressive' process

Understanding the temporal origin(s) of schizophrenia, through specifying the earliest identifiable pathology, might indicate when to look for etiological factor(s), what their nature might be, and how course of illness might evolve from these origins. From this premise, earlier formulations are elaborated to offer a rigorously data-driven model that roots schizophrenia in cerebro-craniofacial dysmorphogenesis, particularly along the mid-line but involving other structures, over weeks 9/10 through 14/15 of gestation. However, a brain that has been compromised very early in fetal life is still subject to the normal endogenous programme of developmental, maturational and involutional processes on which a variety of exogenous biological insults and psychosocial stressors can impact adversely over later pregnancy, through infancy and childhood, to maturation and into old age, to sculpt brain structure and function; it should be emphasised that the effects of such endogenous programmes and exogenous insults on such an already developmentally-compromised brain may be different from their effects on a brain whose early fetal origins were unremarkable. From these early origins, a lifetime trajectory model for schizophrenia from developmental basis to 'neuroprogressive' process is constructed. Thereafter, consideration is given to what the model can explain, including cerebral asymmetry and homogeneity, what it cannot explain, what empirical findings would challenge or disprove the model, what cellular and molecular mechanisms might underpin the model, and what are its implications.

High-performance liquid chromatographic assay for diltiazem in small-volume blood specimens and application to pharmacokinetic studies in rats

A high-performance liquid chromatographic (HPLC) method was developed which involves the use of two 5-microns BDS silica gel columns (15 cm x 4.6 mm I.D.) in series for increased resolution and sensitivity, and an organic mobile phase for both extraction and elution of diltiazem. Plasma samples (400 microliters) were extracted using the organic mobile phase [n-hexane-methanol-dichloromethane-ammonia (370:35:30:0.3)] and the extracts were monitored at 240 nm. Desipramine (30 micrograms ml-1) was the internal standard. The limit of quantification in plasma was 20 ng ml-1 with a correlation coefficient of > or = 0.999 within the 20-800 ng ml-1 standard window. The inter- and intra-assay R.S.D.s were within 5%. The recovery of diltiazem varied from 101.1% at 20 ng ml-1 to 93.7% at 400 ng ml-1. The method was applied to the investigation of diltiazem absorption in a rat. Drug absorption was based on the intestinal single-pass perfusion model. The concentration of diltiazem in all test perfusion solutions was 1 mg ml-1 (2.4 mM) and the flow-rate through the system was 3.33.10(-3) ml s-1. A non-specific mucolytic absorption enhancer was also added to a diltiazem solution and studied in the in situ system. The pharmacokinetics of diltiazem hydrochloride were investigated in two study groups of Wistar rats (n = 4). A two-sample Student's t-test was employed to compare values of the area under the curve (AUC). The pharmacokinetic data indicated that the AUC in the group which received the enhancer [18.12 +/- 5.43 ng ml-1 h-1 (+/- S.D.)] was higher than that in the control group (11.49 +/- 3.67 ng h-1 ml-1), t-test; p = 0.0483. Hence it was shown that administration of an enhancer could increase the oral bioavailability of diltiazem.

Mechanism of irreversible inactivation of phosphomannose isomerases by silver ions and flamazine

Silver ions and silver-containing compounds have been used as topical antimicrobial agents in a variety of clinical situations. We have previously shown that the enzyme phosphomannose isomerase (PMI) is essential for the biosynthesis of Candida albicans cell walls. In this study, we find that PMI can be inhibited by silver ions. This process is shown to be irreversible, and is a two-step process, involving an intermediate complex with a dissociation constant, Ki, of 59 +/- 8 microM, and a maximum rate of inactivation of 0.25 +/- 0.04 min-1 in 50 mM Hepes buffer, pH 8.0 at 37 degrees C. The enzyme can be protected against this inactivation by the substrate mannose 6-phosphate, with a dissociation constant of 0.31 +/- 0.04 mM, close to its Km value. Flamazine (silver sulfadiazine) is a silver-containing antibiotic which is used clinically as a topical antimicrobial and antifungal agent. We compared the ability of silver sulfadiazine and two other silver-containing compounds to irreversibly inactivate C. albicans PMI. The addition of the organic moiety increased the affinity of the compounds, with silver sulfadiazine showing a Ki of 190 +/- 30 nM. In all cases, the maximum inhibition rate was similar, implying a similar rate-determining step. Silver sulfadiazine does not inhibit Escherichia coli PMI, and this suggests a role of the only free cysteine, Cys-150, in the inactivation process. To confirm this, we mutated this residue to alanine in C. albicans PMI. The resultant Cys150 --> Ala mutant protein showed similar Vm and Km values to the wild-type enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Arginine 304 is an active site residue in phosphomannose isomerase from Candida albicans

The reaction catalyzed by Candida albicans phosphomannose isomerase (PMI) (EC 5.3.1.8) has a bell-shaped pH dependence, with pKa's at 5.6 and 8.7. The enzyme can be inhibited in a time-dependent manner using the arginine-specific modification reagent phenylglyoxal. This modification takes place with a rate constant of 0.022 +/- 0.002 min-1 mM-1 at 37 degrees C in 50 mM Hepes buffer, pH 8.5. The enzyme can be protected from this inactivation by the addition of the substrate mannose 6-phosphate at concentrations close to its Km value. The pH dependence of the inactivation reaction shows a single pKa at 9.1 +/- 0.1, which is close to one of the values for the pH dependence of the enzyme-catalyzed reaction. Using [7-14C]phenylglyoxal, it is shown that a single molecule is incorporated into the enzyme in the absence of substrate and that this inactivates the enzyme. This incorporation of radioactivity is prevented by the coincubation with substrate. The modified protein has then been reduced with sodium borohydride to fix the modification and then cleaved with Asp-N protease. The resultant peptides were separated by HPLC, and the radioactivity was counted. Sequencing of the peptide with the highest incorporation level identified it as DNVVRAGFTPKFK, which corresponds to amino acids 300-312 of phosphomannose isomerase. Radioactive counting of the phenylthiohydantoin amino acid derivatives confirmed that the modified amino acid was arginine 304. The role of this residue in the catalytic reaction of phosphomannose isomerase is discussed.

Identification of Cys-150 in the active site of phosphomannose isomerase from Candida albicans

Candida albicans phosphomannose isomerase (PMI) (EC 5.3.1.8) has been recently cloned and overexpressed in Escherichia coli. The enzyme can be irreversibly inactivated by iodoacetate in 50 mM borate buffer, pH 9.0, in a time-dependent manner at a rate of 4.2 +/- 0.03 min-1 M-1. This inhibition can be prevented by the substrate mannose 6-phosphate with a Ks of 0.22 +/- 0.05 mM, slightly lower than its Km value. However, metals such as zinc and cadmium, which are reversible, competitive inhibitors for PMI, do not protect the enzyme against modification. The protein has been labeled by using [2-14C]iodoacetate, in the presence or absence of substrate, and the protein is fully inactivated when 1.0 thiol group is modified per molecule of enzyme. Tryptic maps of the modified protein have been produced. The protected peptide has been identified and sequenced, and the phenylthiohydantoin amino acids have been collected. The modified amino acid is Cys-150. This cysteine residue is conserved in mammalian and yeast phosphomannose isomerases, but not in bacterial species where it is replaced with asparagine. We therefore purified PMI from E. coli and showed that this enzyme is not sensitive to inactivation by iodoacetate. The iodoacetate is presumably inhibiting PMI by sterically blocking the mannose 6-phosphate binding site. Multiple sequence alignment procedures were used to try to identify potential ligands of the zinc atom that is essential for enzyme activity and thus to delineate the active site region.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of the retinoblastoma gene product in bladder carcinoma cells associates with a low frequency of tumor formation

Upon inactivation of both alleles of the retinoblastoma gene (RB), individuals develop the intraocular eye tumor, retinoblastoma. The gene encodes a Mr 110,000 phosphorylated nuclear protein that may be involved in regulation of the cell cycle. Besides retinoblastoma, mutations of the gene have been detected in several other types of tumors, including bladder carcinoma. Up to one-third of bladder carcinomas may contain mutations of the RB gene. Introducing the retinoblastoma gene into single retinoblastoma, osteosarcoma, or prostate carcinoma cell lines suppresses their tumorigenicity as assayed in nude mice. We have sought to extend these results by introducing the retinoblastoma gene into multiple bladder carcinoma lines, and analyzing several of the resulting, cloned lines. We have found that inhibition of tumorigenicity, as assayed by tumor growth in nude mice or growth of cells in soft agar, is the only consistent phenotype observed upon re-expression of RB in all bladder carcinoma cells examined. The effect of RB expression on growth and cellular morphology varied depending on the particular parental cell line. We conclude that RB expression generally correlates with reduced tumorigenicity, but not reduced growth rate, in bladder carcinoma cells.

Suppression of tumorigenicity of human prostate carcinoma cells by replacing a mutated RB gene

Introduction of a normal retinoblastoma gene (RB) into retinoblastoma cells was previously shown to suppress several aspects of their neoplastic phenotype, including tumorigenicity in nude mice, thereby directly demonstrating a cancer suppression function of RB. To explore the possibility of a similar activity in a common adult tumor, RB expression was examined in three human prostate carcinoma cell lines. One of these, DU145, contained an abnormally small protein translated from an RB messenger RNA transcript that lacked 105 nucleotides encoded by exon 21. To assess the functional consequences of this mutation, normal RB expression was restored in DU145 cells by retrovirus-mediated gene transfer. Cells that maintained stable exogenous RB expression lost their ability to form tumors in nude mice, although their growth rate in culture was apparently unaltered. These results suggest that RB inactivation can play a significant role in the genesis of a common adult neoplasm and that restoration of normal RB-encoded protein in tumors could have clinical utility.

Homozygous deletion of the retinoblastoma gene in an acute lymphoblastic leukemia (T) cell line

Human leukemia cell lines were examined for the status of the retinoblastoma (RB) protein by immunoblotting analysis using antibodies raised against the TrpE-RB fusion protein. One of 16 cell lines examined, the T-cell acute lymphoblastic leukemia (ALL) line HSB-2, lacked the 110-Kd RB protein. Southern blot analysis of genomic DNA extracted from HSB-2 cells showed a large homozygous deletion of the RB gene, stretching from exon 18 beyond exon 27. Northern blot analysis showed multiple, abnormal RB transcripts in HSB-2. A truncated protein (72 Kd) was detected with 35S-methionine labeling but not with 32P-orthophosphate labeling of the HSB-2 cells. The genomic deletion of greater than 85 kb DNA at the RB locus (13q14) was not detectable in the karyotype of the HSB-2 cells. Among the 16 human leukemia cell lines examined for the status of the RB gene, only one, the HSB-2 line, showed an abnormal RB protein. Further study of primary leukemia and lymphoma samples appears to be warranted.

Phosphorylation of the retinoblastoma gene product is modulated during the cell cycle and cellular differentiation

Introduction of an exogenous retinoblastoma (RB) gene in RB-deficient retinoblastoma or osteosarcoma cells has been shown to suppress their neoplastic phenotype. In experiments designed to explore the potential mechanism of RB tumor suppression, we report here that the phosphorylation state of RB protein is modulated during normal cellular events. In resting cells, RB protein is present in its least phosphorylated form; in rapidly proliferating cells, RB protein is highly phosphorylated. Maximal phosphorylation is associated with S phase of the cell cycle. Induction of differentiation in several human leukemia cell lines by treatment with phorbol ester or retinoic acid leads to dephosphorylation of RB. Time course studies indicate that RB dephosphorylation precedes the total arrest of cell growth during differentiation. These observations strongly suggest that the function of RB protein is modulated by a phosphorylation/dephosphorylation mechanism during cell proliferation and differentiation.