Subcortical brain volume abnormalities in 2028 individuals with schizophrenia and 2540 healthy controls via the ENIGMA consortium

The profile of brain structural abnormalities in schizophrenia is still not fully understood, despite decades of research using brain scans. To validate a prospective meta-analysis approach to analyzing multicenter neuroimaging data, we analyzed brain MRI scans from 2028 schizophrenia patients and 2540 healthy controls, assessed with standardized methods at 15 centers worldwide. We identified subcortical brain volumes that differentiated patients from controls, and ranked them according to their effect sizes. Compared with healthy controls, patients with schizophrenia had smaller hippocampus (Cohen's d=-0.46), amygdala (d=-0.31), thalamus (d=-0.31), accumbens (d=-0.25) and intracranial volumes (d=-0.12), as well as larger pallidum (d=0.21) and lateral ventricle volumes (d=0.37). Putamen and pallidum volume augmentations were positively associated with duration of illness and hippocampal deficits scaled with the proportion of unmedicated patients. Worldwide cooperative analyses of brain imaging data support a profile of subcortical abnormalities in schizophrenia, which is consistent with that based on traditional meta-analytic approaches. This first ENIGMA Schizophrenia Working Group study validates that collaborative data analyses can readily be used across brain phenotypes and disorders and encourages analysis and data sharing efforts to further our understanding of severe mental illness.

Cortical abnormalities in bipolar disorder: an MRI analysis of 6503 individuals from the ENIGMA Bipolar Disorder Working Group

Despite decades of research, the pathophysiology of bipolar disorder (BD) is still not well understood. Structural brain differences have been associated with BD, but results from neuroimaging studies have been inconsistent. To address this, we performed the largest study to date of cortical gray matter thickness and surface area measures from brain magnetic resonance imaging scans of 6503 individuals including 1837 unrelated adults with BD and 2582 unrelated healthy controls for group differences while also examining the effects of commonly prescribed medications, age of illness onset, history of psychosis, mood state, age and sex differences on cortical regions. In BD, cortical gray matter was thinner in frontal, temporal and parietal regions of both brain hemispheres. BD had the strongest effects on left pars opercularis (Cohen's d=-0.293; P=1.71 × 10^-21), left fusiform gyrus (d=-0.288; P=8.25 × 10^-21) and left rostral middle frontal cortex (d=-0.276; P=2.99 × 10^-19). Longer duration of illness (after accounting for age at the time of scanning) was associated with reduced cortical thickness in frontal, medial parietal and occipital regions. We found that several commonly prescribed medications, including lithium, antiepileptic and antipsychotic treatment showed significant associations with cortical thickness and surface area, even after accounting for patients who received multiple medications. We found evidence of reduced cortical surface area associated with a history of psychosis but no associations with mood state at the time of scanning. Our analysis revealed previously undetected associations and provides an extensive analysis of potential confounding variables in neuroimaging studies of BD.

Widespread white matter microstructural differences in schizophrenia across 4322 individuals: results from the ENIGMA Schizophrenia DTI Working Group

The regional distribution of white matter (WM) abnormalities in schizophrenia remains poorly understood, and reported disease effects on the brain vary widely between studies. In an effort to identify commonalities across studies, we perform what we believe is the first ever large-scale coordinated study of WM microstructural differences in schizophrenia. Our analysis consisted of 2359 healthy controls and 1963 schizophrenia patients from 29 independent international studies; we harmonized the processing and statistical analyses of diffusion tensor imaging (DTI) data across sites and meta-analyzed effects across studies. Significant reductions in fractional anisotropy (FA) in schizophrenia patients were widespread, and detected in 20 of 25 regions of interest within a WM skeleton representing all major WM fasciculi. Effect sizes varied by region, peaking at (d=0.42) for the entire WM skeleton, driven more by peripheral areas as opposed to the core WM where regions of interest were defined. The anterior corona radiata (d=0.40) and corpus callosum (d=0.39), specifically its body (d=0.39) and genu (d=0.37), showed greatest effects. Significant decreases, to lesser degrees, were observed in almost all regions analyzed. Larger effect sizes were observed for FA than diffusivity measures; significantly higher mean and radial diffusivity was observed for schizophrenia patients compared with controls. No significant effects of age at onset of schizophrenia or medication dosage were detected. As the largest coordinated analysis of WM differences in a psychiatric disorder to date, the present study provides a robust profile of widespread WM abnormalities in schizophrenia patients worldwide. Interactive three-dimensional visualization of the results is available at www.enigma-viewer.org.

Subcortical volumetric abnormalities in bipolar disorder

Considerable uncertainty exists about the defining brain changes associated with bipolar disorder (BD). Understanding and quantifying the sources of uncertainty can help generate novel clinical hypotheses about etiology and assist in the development of biomarkers for indexing disease progression and prognosis. Here we were interested in quantifying case-control differences in intracranial volume (ICV) and each of eight subcortical brain measures: nucleus accumbens, amygdala, caudate, hippocampus, globus pallidus, putamen, thalamus, lateral ventricles. In a large study of 1710 BD patients and 2594 healthy controls, we found consistent volumetric reductions in BD patients for mean hippocampus (Cohen's d=-0.232; P=3.50 × 10-7) and thalamus (d=-0.148; P=4.27 × 10-3) and enlarged lateral ventricles (d=-0.260; P=3.93 × 10-5) in patients. No significant effect of age at illness onset was detected. Stratifying patients based on clinical subtype (BD type I or type II) revealed that BDI patients had significantly larger lateral ventricles and smaller hippocampus and amygdala than controls. However, when comparing BDI and BDII patients directly, we did not detect any significant differences in brain volume. This likely represents similar etiology between BD subtype classifications. Exploratory analyses revealed significantly larger thalamic volumes in patients taking lithium compared with patients not taking lithium. We detected no significant differences between BDII patients and controls in the largest such comparison to date. Findings in this study should be interpreted with caution and with careful consideration of the limitations inherent to meta-analyzed neuroimaging comparisons.

Role of the Kv4.3 K+ channel in ventricular muscle. A molecular correlate for the transient outward current

The expression of 15 different K+ channels in canine heart was examined, and a new K+ channel gene (Kv4.3), which encodes a rapidly inactivating K+ current, is described. The Kv4.3 channel was found to have biophysical and pharmacological properties similar to the native canine transient outward current (I(to)). The Kv4.3 gene is also expressed in human and rat heart. It is concluded that the Kv4.3 channel underlies the bulk of the I(to) in canine ventricular myocytes, and probably in human myocytes. Both the Kv4.3 and Kv4.2 channels are likely to contribute to the I(to) in rat heart, and differential expression of these two channels can account for observed differences in the kinetic properties of the I(to) in different regions of rat ventricle. There are significant differences in the pattern of K+ channel expression in canine heart, compared with rat heart, and these differences may be an adaptation to the different requirements for cardiac function in mammals of markedly different sizes. It is possible that the much longer ventricular action potential duration observed in canine heart compared with rat heart is due, in part, to the lower levels of Kv1.2, Kv2.1, and Kv4.2 gene expression in canine heart.

The structure of anxiety symptoms among preschoolers

This study examined whether anxiety symptoms in preschoolers reflect subtypes of anxiety consistent with current diagnostic classification systems, or should be better regarded as representing a single dimension. Parents of a large community sample of preschoolers aged 2.5 to 6.5 years rated the frequency with which their children experienced a wide range of anxiety problems. Exploratory factor analysis indicated four or five factors and it was unclear whether separation anxiety and generalized anxiety represented discrete factors. Results of confirmatory factor analyses indicated a superior fit for a five-correlated-factor model, reflecting areas of social phobia, separation anxiety, generalized anxiety, obsessive-compulsive disorder and fears of physical injury, broadly consistent with DSM-IV diagnostic categories. A high level of covariation was found between factors, which could be explained by a single, higher order model, in which first order factors of anxiety subtypes loaded upon a factor of anxiety in general. No significant differences were found in prevalence of anxiety symptoms across genders. Symptoms of PTSD in this sample were rare.

Ultrasonographic evaluation of diaphragmatic motion

OBJECTIVE

To evaluate the technical feasibility and utility of ultrasonography in the study of diaphragmatic motion at our institution.

METHODS

The study consisted of 2 parts. For part I, in 23 volunteers we performed 23 studies on 46 hemidiaphragms with excursions documented on M-mode ultrasonography For part II, in 22 patients we performed 52 studies in 102 hemidiaphragms. In 50 studies both hemidiaphragms were studied, and in another 2 studies only 1 hemidiaphragm was studied. Patients' ages ranged from birth to 66 years (mean, 23 years). There were 16 male and 6 female patients. Indications for the study were (1) suggestion of paralysis of the diaphragm (n = 22); (2) if the diaphragm was already known to be paralyzed, for evaluation of response to phrenic nerve or pacer stimulation (n = 9); and (3) follow-up of previous findings (n = 21). Patients were examined in the supine position in the longitudinal semicoronal plane from a subcostal or low intercostal approach. Motion was documented with real-time ultrasonography and measured with M-mode ultrasonography.

RESULTS

Of the 102 clinical hemidiaphragms studied, findings included normal motion (n = 42), decreased motion (n = 22), no motion (n = 6), paradoxical motion (n = 10), positive pacer response (n = 13), negative pacer response (n = 2), positive phrenic stimulation (n = 6), and negative phrenic stimulation (n = 1). There were no failures of visualization.

CONCLUSIONS

Ultrasonography proved feasible and useful in evaluating diaphragmatic motion. In our practice it has replaced fluoroscopy. Ultrasonography has advantages over traditional fluoroscopy, including portability, lack of ionizing radiation, visualization of structures of the thoracic bases and upper abdomen, and the ability to quantify diaphragmatic motion.

Practice parameter: corticosteroid treatment of Duchenne dystrophy: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society

BACKGROUND

The Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society develop practice parameters as strategies for patient management based on analysis of evidence.

OBJECTIVE

To review available evidence on corticosteroid treatment of boys with Duchenne dystrophy.

METHODS

Relevant literature was reviewed, abstracted, and classified. Recommendations were based on a four-tiered scheme of evidence classification, and areas for future research are defined.

RESULTS

Seven class I studies and numerous less rigorous trials all demonstrated that corticosteroid treatment for 6 months with prednisone (0.75 or 1.5 mg/kg/day) increased muscle strength, performance, and pulmonary function and significantly slowed the progression of weakness. Two class I trials examined the effect of lower dosage of prednisone (0.30 and 0.35 mg/kg/day), demonstrated lesser but similar benefits, and showed a lower frequency of side effects (e.g., weight gain). The only significant side effects in all class I trials were weight gain and development of a cushingoid facial appearance. One longer-term trial of daily prednisone (0.3 to 0.7 mg/kg/day), a class III study, showed prolongation of functional ability and slower progression of weakness in patients during 3 years of treatment. One class IV, open trial of alternate-day prednisone (2 mg/kg for 2 months, then two-thirds dose every other day) extended ambulation by approximately 2 years in treated compared with untreated patients. Deflazacort, a corticosteroid similar in structure to prednisone, produced similar improvement in muscle strength and function with a similar side effect profile.

CONCLUSIONS

Prednisone has been demonstrated to have a beneficial effect on muscle strength and function in boys with Duchenne dystrophy and should be offered (at a dose of 0.75 mg/kg/day) as treatment. If side effects require a decrease in prednisone, tapering to dosages as low as 0.3 mg/kg/day gives less robust but significant improvement. Deflazacort (0.9 mg/kg/day) can also be used for the treatment of Duchenne dystrophy in countries in which it is available. Benefits and side effects of corticosteroid therapy need to be monitored. The offer of treatment with corticosteroids should include a balanced discussion of potential risks.

Noninvasive ductal carcinoma of the breast: the relevance of histologic categorization

A consecutive series of 130 review-confirmed cases of noninvasive ductal carcinoma of breast (DCIS) in women without previous breast carcinoma was analyzed. Histologic variables assessed included histologic pattern, nuclear grade, necrosis, and involved duct counts. These were correlated with presentation, extent of DCIS in the breast, completeness of excision, and outcome. Comedo DCIS had an occult presentation significantly more often than noncomedo DCIS. Micropapillary DCIS was significantly more likely than other patterns to involve multiple quadrants of breast, irrespective of nuclear grade or necrosis. Solid DCIS was significantly more often completely excised when compared with all other patterns, while high-grade DCIS was significantly more often incompletely excised compared with low-grade DCIS. Follow-up showed invasive recurrence in 16% of cases treated by primary local excision only and 3% cases treated by mastectomy or with re-excision. Of local excision cases with follow-up longer than 3 years, 22% had invasive recurrence. Invasive recurrence only followed high-grade DCIS and most often followed comedo DCIS. The need for strict definition of categories of DCIS is stressed.

Role for macrophage migration inhibitory factor in asthma

Macrophage migration inhibitory factor (MIF) is an immunologic regulator that is expressed in inflammatory and autoimmune disorders. We investigated MIF's role in asthma using genetic approaches in a mouse model and in a cohort of asthma patients. Mice genetically deficient in MIF that were primed and aerosol-challenged with ovalbumin showed less pulmonary inflammation and lower airway hyperresponsiveness than genetically matched, wild-type controls. MIF deficiency also resulted in lower titers of specific IgE, IgG(1), and IgG(2a), and decreased pulmonary, T(H)2 cytokine levels. IL-5 concentrations were lower and corresponded to decreased eosinophil numbers in bronchoalveolar lavage fluid. T cell studies also showed a lower level of antigen-specific responses in MIF-KO versus wild-type mice. In an analysis of 151 white patients with mild, moderate, or severe asthma (Global Initiative for Asthma criteria), a significant association was found between mild asthma and the low-expression, 5-CATT MIF allele. Pharmacologic inhibition of MIF may be beneficial and could be guided by the MIF genotype of affected individuals.

Nuclear export signal located within theDNA-binding domain of the STAT1transcription factor

Latent signal transducers and activators of transcription (STATs) reside in the cytoplasm but rapidly accumulate in the nucleus following cytokine stimulation. Nuclear accumulation requires specific tyrosine phosphorylation and STAT dimerization. The presence of STATs in the nucleus is transient, however, and within hours the STATs reappear in the cytoplasm. Results indicate that STAT1 can be dephosphorylated in the nucleus and actively exported by the chromosome region maintenance 1 (CRM1) export receptor. CRM1 recognizes a specific amino acid sequence located within the DNA-binding domain of STAT1. This region shares sequence and functional properties of characterized nuclear export signals. The location of this sequence within STAT1 suggests that it is not accessible to CRM1 when STAT1 is bound to DNA. Evidence is presented to support a model in which STAT1 is tyrosine dephosphorylated in the nucleus and dissociates from DNA, allowing recognition by CRM1 and nuclear export. The regulated export of STAT1 may contribute to silencing of the signal pathway and/or to re-establish STAT1 in the cytoplasm to monitor activity of receptor-kinase signals.

Electroconvulsive therapy: results in depressive illness from the Leicestershire trial

Electroconvulsive therapy was investigated in a double blind trial. Altogether 186 clinically selected patients were referred to the trial, but 48 of these did not participate. According to the present state examination, 95 of the remaining 138 patients fell into one of the classes of major depression. Patients were randomly allocated to a course of real or simulated electroconvulsive therapy. Treatment was given twice a week with a maximum of eight treatments. On the Hamilton depressive rating scale the improvement in the group given real treatment was significantly greater than that in the group given simulated treatment both at two weeks (p = 0.014) and at four weeks (p = 0.0001). At follow up at 12 and 28 weeks there was no difference between the treatment groups. At the end of the four week trial consultants, who were blind to the allocation of treatment, rated the patients who had received real treatment as having made a significantly greater improvement than the patients who had received simulated treatment (p less than 0.00005). Further analysis showed that electroconvulsive therapy was effective in depression associated with delusions and in depression associated with retardation.

Exaggerated neural response to emotional faces in patients with bipolar disorder and their first-degree relatives

Neuroimaging studies have demonstrated abnormalities in patients with bipolar disorder, including overactivity in anterior limbic structures in response to fearful or happy facial expressions. We investigated whether such anomalies might constitute heritable deviations underlying bipolar disorder, by virtue of being detectable in unaffected relatives carrying genetic liability for illness. Twenty patients with bipolar I disorder, twenty of their unaffected 1st degree relatives and twenty healthy volunteers participated in functional magnetic resonance imaging experiments of facial emotion processing. In one of these experiments, the participants watched faces expressing fear of varying intensities (moderate and high), intermixed with the non-emotional faces, and in another experiment - faces expressing moderate or high degrees of happiness intermixed with non-emotional faces. Repeated measures 2x3x3 ANOVA with emotion (fear and happy), intensity (neutral, moderate, and high) as within-subjects variables and group (patients, relatives, and controls) as between-subjects variable produced two clusters of differential activation, located in medial prefrontal cortex and left putamen. Activity in medial prefrontal cortex was greater in patients and in relatives compared with healthy volunteers in response to both fearful and happy faces. Activity in left putamen in response to moderate fear was greater in patients and in relatives compared with controls. Patients (but not relatives) showed also a greater activation in response to high intensity happy faces, compared with controls. Region of Interest analysis of amygdala activation showed increased activity in left amygdala in both patients and relatives groups in response to intensively happy faces. Exaggerated medial prefrontal cortical and subcortical (putamen and amygdala) responses to emotional signals may represent heritable neurobiological abnormalities underlying bipolar disorder.

Early and late environmental risk factors for schizophrenia

Although a high proportion of liability to schizophrenia is under genetic control, a number of environmental risk factors have been identified. The earliest of these are complications of pregnancy and birth, though whether these cause or reflect disturbed brain development is not absolutely clear. Neurodevelopmental deviance is also indicated by neurological dysfunction, social, behavioural and cognitive deficits during childhood. Immigrant status is a significant risk factor, especially prominent among the African Caribbean population in England, though the mechanism is unknown. Later environmental risk factors include adverse life events and substance abuse. An additive model of multiple genetic and environmental risk factors of small effect may be too simplistic and an interactive model where genetic predisposition is compounded by environmental effects is more in keeping with current evidence. The nature of such interactions can be explored more fully when susceptibility genes for schizophrenia are identified.

The Edinburgh randomised trial of breast cancer screening: results after 10 years of follow-up

The Edinburgh Randomised Trial of Breast Cancer Screening recruited 44,288 women aged 45-64 years into the initial cohort of the trial during 1978-81, and 10 years of follow-up is now complete. A total of 22,944 women were randomised into the study group and were offered screening for 7 years; the remaining women formed the control group. After 10 years, breast cancer mortality is 14-21% lower in the study group than in the controls depending on the precise definition of the end point. These differences are not statistically significant; for breast cancer as the underlying cause of death the relative risk is 0.82 (95% confidence interval 0.61-1.11). Rates of locally advanced and metastatic cancer were substantially lower in the study group, but screening has failed to achieve marked reductions in rates of small node-positive cancers. Those women who accepted the final invitation to screening have been monitored over the 3 year period prior to their first screen under the UK service screening programme. Interval cases, expressed as a proportion of the control incidence, increased from 12% in the first year to 67% in the third year. The reduction in breast cancer mortality for older women (aged at least 50 years) is the same as that for the total study group for this duration of follow-up. For analyses of breast cancer mortality in younger women updates recruited to the trial from 1982 to 1985 (10,383 women with 6-8 years' follow-up) have been included. The reduction in breast cancer mortality for women aged 45-49 years at entry was 22% (relative risk = 0.78, 95% confidence interval = 0.46-1.31).

Clinical heterogeneity in senile dementia

Roth and Morrisey (1952), in isolating senile dementia (senile psychosis) as a distinct nosological entity, used as their definition “an illness of insidious onset pursuing a uniformly progressive course with steadily augmenting mental decay”. In 1955 Roth defined senile psychosis as “a condition with a history of gradual and continuously progressive failure in the common activities of everyday life and a clinical picture dominated by failure of memory and intellect and disorganization of a personality, where these were not attributable to specific causes such as infection, neoplasm, chronic intoxication or cerebral vascular disease known to have produced cerebral infarction”. Kay (1962) defines dementia as a “gross deterioration of intellectual capacity and of memory, together with severe and persistent disorientation for time and place”. He diagnosed senile dementia “when there was no evidence of focal brain disease”. Roth et al. (1966) describe senile dementia as “the extreme form of intellectual decay of old age”.

Patients' knowledge of pregnancy-related issues in inflammatory bowel disease and validation of a novel assessment tool ('CCPKnow')

BACKGROUND

Inflammatory bowel diseases (IBD) require complex therapeutic decisions and life choices concerning pregnancy, but little is known about patient's knowledge of IBD and its treatment before and during pregnancy.

AIM

To develop a novel tool (Crohn's and Colitis Pregnancy Knowledge Score 'CCPKnow') to assess knowledge of pregnancy-related issues in IBD. The validated tool was then applied to determine knowledge in patients.

METHOD

Discriminate ability of 'CCPKnow' was validated in four groups with different levels of IBD knowledge. Reliability and readability were tested by Cronbach-α and Flesch-Kencaid. Construct validity was subsequently assessed against general IBD knowledge (CCKnow) in 145 women with IBD. Associations between patient factors and knowledge were studied.

RESULTS

Median CCPKnow scores differed significantly between the validation groups (P < 0.001). CCPKnow displayed excellent internal consistency, reliability (Cronbach-α 0.94), readability (reading age 9 years) and close correlation with CCKnow (Spearman's ρ 0.64; P < 0.001). Of 145 patients, 44.8% had poor, 27.6% adequate, 17.3% good and only 10.3% very good knowledge. Better knowledge was associated with Caucasian ethnicity, higher income, having a partner, having children, Crohn's and Colitis Association membership, longer disease duration and Crohn's disease.

CONCLUSIONS

Crohn's and Colitis Pregnancy Knowledge Score, a novel knowledge assessment tool of pregnancy and IBD, demonstrated excellent test characteristics. We found that nearly half of the women with IBD had poor knowledge, identifying a pressing need for better education.

Risk of breast cancer in women with palpable breast cysts: a prospective study. Edinburgh Breast Group

BACKGROUND

7% of women in the western world develop palpable breast cysts. Studies of the relation between cysts and breast cancer have conflicting results. There are two clearly defined types of cyst. We investigated whether one cyst type is associated with a higher rate of breast-cancer development than the other.

METHODS

We studied 1374 women with palpable breast cysts presenting between 1981 and 1987, who had cysts aspirated between 1981 and 1989. Cysts were classified as type I if the sodium/potassium (Na+/K+) ratio in the cyst fluid was less than 3, or type II if the Na+/K+ ratio was 3 or more. Data on incidence of breast cancer were available until January, 1995, and we compared them with the expected numbers of cancers calculated from age-specific breast-cancer incidence in Scotland in 1988.

FINDINGS

65 cancers developed during follow-up. The overall standardised incidence rate of breast cancer in patients with palpable cysts was 2.81 (95% CI 2.17-3.59). The relative incidence rate was increased for all cyst types. The standardised incidence rate of developing breast cancer among women younger than 45 years was highest at 5.94 (2.97-10.63), with a significant trend for decreasing relative incidence rate with age (p<0.05). Women older than 54 years had a standardised incidence rate of 1.73 (0.86-3.10). The standardised incidence rate of breast cancer was highest in the first year after aspiration (7.02 [3.73-12.00]) but the risk was still raised after 5 years (2.68 [1.84-3.76]).

INTERPRETATION

Women with breast cysts are at an increased risk of breast cancer, especially at younger ages. The type of cyst did not alter the associated relative incidence rate of breast-cancer development.

Are auditory P300 and duration MMN heritable and putative endophenotypes of psychotic bipolar disorder? A Maudsley Bipolar Twin and Family Study

BACKGROUND

Impaired P300 auditory response has been reported in patients with psychotic bipolar disorder (BPD) and unaffected relatives of psychotic bipolar patients. Deficits in mismatch negativity (MMN), however, have not been observed in bipolar patients. To our knowledge, no family study of MMN in BPD has been reported. The current study combined the Maudsley twin and bipolar family samples using genetic model fitting analyses to: (1) assess the relationship between BPD and MMN, (2) substantiate the association between psychotic BPD and P300 variables, (3) verify the genetic overlap of BPD with P300 amplitude previously reported in the twin sample, and (4) examine the shared genetic influences between BPD and bilateral temporal scalp locations of P300 components.

METHOD

A total of 301 subjects were included in this study, including 94 twin pairs, 31 bipolar families, and 39 unrelated healthy controls. Statistical analyses were based on structural equation modelling.

RESULTS

Both P300 and MMN are heritable, with heritability estimates of 0.58 for MMN, 0.68-0.80 for P300 amplitude, and 0.21-0.56 for P300 latency. The bipolar patients and their relatives showed normal MMN. No significant association, either genetic or environmental, was found with BPD. BPD was significantly associated with reduced P300 amplitude and prolonged latency on midline and bilateral temporal-posterior scalp areas. Shared genetic factors were the main source of these associations.

CONCLUSIONS

The results confirm that MMN is not an endophenotype for psychotic BPD whereas P300 amplitude and latency components are valid endophenotypes for psychotic BPD.

Measuring the human retinal oxygenation response to a hyperoxic challenge using MRI: eliminating blinking artifacts and demonstrating proof of concept

The retinal oxygenation response to a hyperoxic challenge measured using MRI appears to be an early and accurate marker of retinopathy risk in experimental models, with promising clinical potential. However, the application of this technique in humans is limited by blinking artifacts that can confound detection of subtle signal intensity changes. We asked subjects to refrain from blinking during a 12-s fast low-angle shot (FLASH) image, and to blink if needed during the following 3-s rest period. This no-blink blink cycle was repeated sequentially 20 times during either room-air or 100% oxygen breathing. Significant change (P < 0.05) was detected for the first time from the resultant blinking-artifact-free images in the preretinal vitreous oxygen tension (upper limit of about 13 mm Hg (1.8 KPa, N = 3)) following a 10-min hyperoxic inhalation challenge. These results provide the proof-of-concept data needed for future MRI evaluation of the retinal oxygenation response and human retinopathy, such as diabetic retinopathy.

Brain MRI abnormalities in schizophrenia: same genes or same environment?

BACKGROUND

Structural brain volume abnormalities are among the most extensively studied endophenotypes in schizophrenia. Bivariate genetic model fitting (adjusted to account for selection) was used to quantify the genetic relationship between schizophrenia and brain volumes and to estimate the heritability of these volumes.

METHOD

We demonstrated by simulation that the adjusted genetic model produced unbiased estimates for endophenotype heritability and the genetic and environmental correlations. The model was applied to brain volumes (whole brain, hippocampus, third and lateral ventricles) in a sample of 14 monozygotic (MZ) twin pairs concordant for schizophrenia, 10 MZ discordant pairs, 17 MZ control pairs, 22 discordant sibling pairs, three concordant sibling pairs, and 114 healthy control subjects.

RESULTS

Whole brain showed a substantial heritability (88%) and lateral ventricles substantial common environmental effects (67%). Whole brain showed a significant genetic correlation with schizophrenia, whereas lateral ventricles showed a significant individual specific correlation with schizophrenia. There were significant familial effects for hippocampus and third ventricle, but the analyses could not resolve whether these were genetic or environmental in origin (around 30%each).

CONCLUSIONS

Using genetic model fitting on twin and sibling data we have demonstrated differential sources of covariation between schizophrenia and brain volumes, genetic in the case of whole brain volume and individual specific environment in the case of lateral ventricles.

Gastric emptying of solid food in patients with gastroesophageal reflux

While delayed gastric emptying of solid food has been reported in patients with symptoms of gastroesophageal reflux, the study populations were not defined by 24-h intraesophageal pH monitoring. Moreover, the influence that the gastric emptying rate may have on patterns of reflux during the day or night, as well as on esophagitis, is not known. In this study, we compared the gastric emptying rate of solid food (in vivo intracellular labeled chicken liver) observed in asymptomatic control volunteers (n = 15) with that of symptomatic patients with an abnormal 24-h pH record who had either the presence (n = 22) or absence (n = 11) of endoscopic esophagitis. We found no significant difference in the gastric emptying rate between the asymptomatic control volunteers and the symptomatic patients with and without esophagitis. Moreover, there was no significant correlation between the gastric emptying rate and the degree of daytime or nighttime distal esophageal acid exposure found during 24-h intraesophageal pH monitoring. Only 6% of the symptomatic patients had a gastric emptying rate that exceeded the mean value plus 2 SD of that found in the asymptomatic control volunteers. We believe these support a de-emphasis of the role that delayed gastric emptying of solid food may play in the pathophysiology of gastroesophageal reflux in most patients.