Functional connectivity alterations between default mode network and occipital cortex in patients with obsessive-compulsive disorder (OCD)

Introduction

A meta-analysis by Gürsel et al. (2018) found altered functional connectivity in OCD patients within and between default mode (DMN), salience (SN), and frontoparietal networks (FPN), as well as evidence for aberrant fronto-striatal circuitry.

Objectives

Testing the replicability of meta-analysis rsfMRI findings in OCD patients.

Methods

We measured functional connectivity during resting-state fMRI in a sample of OCD patients (n=24) and controls matched for age and sex (n=33). The CONN toolbox implemented in SPM was used to perform seed-to-voxel analysis using 30 seed regions based on the previous meta-analytic findings.

Results

OCD patients showed reduced functional connectivity between SN and DMN compared to controls, replicating previous findings. We did not observe significant group differences of functional connectivity within the DMN, SN, or FPN. The strongest finding consisted of altered connectivity between DMN and SN to the visual network. OCD patients showed reduced functional connectivity between the left lateral parietal seed (LPl) and the inferior lateral occipital pole left (iLOCl) compared to controls. Furthermore, the LPl was found to be hyperconnected with the right superior lateral occipital cortex (sLOCr) and the right precuneus. This finding was positively correlated to OCD symptom severity, especially compulsions.

Conclusions

Our findings replicated partly the meta-analysis findings, specifically reduced connectivity between SN and DMN. Using seeds based on the meta-analysis, we identified aberrations between the SN and, in particular, the DMN to the visual network. This raises the question about the visual system’s involvement in OCD symptoms and the abnormal connectivity of a unimodal region to the multimodal DMN.

Disclosure

No significant relationships.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Glucose and the wandering mind: not paying attention or simply out of fuel?

RATIONALE/OBJECTIVES

The impact of raising glycaemia by ingestion of a glucose drink has revealed cognitive facilitation, particularly for memory and attention. This study aimed to extend current knowledge by examining, for the first time, whether glucose load also moderates task-related (TRT) and task-unrelated thoughts (TUT) during activities that vary in their requirement for sustained attention.

METHOD

A 2 (25 g glucose vs. placebo) × 2 (fast vs. slow version of the Sustained Attention to Response Task (SART)) repeated measures, counterbalanced design was used with 16 healthy adults. Self-report questionnaires probed participants' levels of TRT and TUT during SART performance. Prior to testing, the Short Imaginal Processes Inventory (SIPI) was also administered to help pinpoint the nature of thought processes during the task before and after treatment.

RESULTS

Analysis of variance revealed no significant effect of treatment; however, we report a pattern of results that is consistent with glucose facilitation effects on task accuracy for more demanding attention tasks (d = 0.56). Additionally, glucose improved the monitoring and task reflection as measured by TRT (d = 0.33) in the more demanding task but no effect on TUT. Probing the nature of thought processes further, we also report two novel correlations (in the placebo) between fears of failure (indexed by the SIPI) and the number of TUT episodes and perceived poor attention control (indexed by the SIPI) and number of TUT and speculate that glucose may act to buffer against TUT episodes under externally demanding situations.

CONCLUSIONS

These data extend previous research examining the glucose facilitation effect to the processing of internal thought processes.

Melanoma sentinel node biopsy and prediction models for relapse and overall survival

BACKGROUND

To optimise predictive models for sentinal node biopsy (SNB) positivity, relapse and survival, using clinico-pathological characteristics and osteopontin gene expression in primary melanomas.

METHODS

A comparison of the clinico-pathological characteristics of SNB positive and negative cases was carried out in 561 melanoma patients. In 199 patients, gene expression in formalin-fixed primary tumours was studied using Illumina's DASL assay. A cross validation approach was used to test prognostic predictive models and receiver operating characteristic curves were produced.

RESULTS

Independent predictors of SNB positivity were Breslow thickness, mitotic count and tumour site. Osteopontin expression best predicted SNB positivity (P=2.4 × 10⁻⁷), remaining significant in multivariable analysis. Osteopontin expression, combined with thickness, mitotic count and site, gave the best area under the curve (AUC) to predict SNB positivity (72.6%). Independent predictors of relapse-free survival were SNB status, thickness, site, ulceration and vessel invasion, whereas only SNB status and thickness predicted overall survival. Using clinico-pathological features (thickness, mitotic count, ulceration, vessel invasion, site, age and sex) gave a better AUC to predict relapse (71.0%) and survival (70.0%) than SNB status alone (57.0, 55.0%). In patients with gene expression data, the SNB status combined with the clinico-pathological features produced the best prediction of relapse (72.7%) and survival (69.0%), which was not increased further with osteopontin expression (72.7, 68.0%).

CONCLUSION

Use of these models should be tested in other data sets in order to improve predictive and prognostic data for patients.

Spatial and temporal epidemiology of sporadic human cases of Escherichia coli O157 in Scotland, 1996-1999

In Scotland, between 1995 and 2000 there were between 4 and 10 cases of illness per 100000 population per year identified as being caused by Escherichia coli O157, whereas in England and Wales there were between 1 and 2 cases per 100000 population per year. Within Scotland there is significant regional variation. A cluster of high rate areas was identified in the Northeast of Scotland and a cluster of low rate areas in central-west Scotland. Temporal trends follow a seasonal pattern whilst spatial effects appeared to be distant rather than local. The best-fit model identified a significant spatial trend with case rate increasing from West to East, and from South to North. No statistically significant spatial interaction term was found. In the models fitted, the cattle population density, the human population density, and the number of cattle per person were variously significant. The findings suggest that rural/urban exposures are important in sporadic infections.

Aromatherapy and behaviour disturbances in dementia: a randomized controlled trial

A random controlled trial of the relaxing effects of an aromatherapy massage on disordered behaviour in dementia was conducted. Twenty-one patients were randomly allocated into one of three conditions, aromatherapy and massage (AM), conversation and aromatherapy (CA) and massage only (M). AM showed the greatest reduction in the frequency of excessive motor behaviour of all three conditions. This reached statistical significance between the hours of three and four pm (p < 0.05). Post hoc analysis suggested that at this time of day the AM consistently reduced motor behaviour when compared with CA (p = 0.05). This provides preliminary evidence of a measurable sedative effect of aromatherapy massage on dementia within a robust scientific paradigm. Further research is recommended with an expanded sample size.

Psychometric evaluation of a short observational tool for small-scale research projects in dementia

Dementia is a degenerating illness and the lack of a reliable measure of self-report in particular presents particular difficulties for research. Often in the later stages of dementia behavioural measurement is the only tool available for the evaluation of treatment techniques. This paper describes and evaluates a short observational tool suitable for clinical assessment purposes. The scale has been shown to have the potential for adequate inter-rater reliability, test retest reliability, and convergent and divergent validity, if the study limitations reflecting statistical rather than ecological validity, and limitations of sample size are borne in mind.

Intra-arterial thrombolysis should be the initial treatment of the acutely ischaemic lower limb

We review and discuss the initial management of acute arterial occlusion. Thrombolytic therapy has been available for over 25 years but has failed to gain universal acceptance in the initial management of this condition. Support for the use of initial thrombolytic therapy in all patients is based on the following arguments. It may be difficult to distinguish clinically between an embolic or a thrombotic occlusion, and inappropriate surgery in the latter may have disastrous consequences. Therefore, arteriography should be performed in all patients. It is then easy to place a catheter for thrombolytic therapy. This therapy allows treatment of associated medical problems before definitive surgery, and it may enable a more accurate assessment of the obstruction and better planning of surgery after dissolution of some of the occluding thrombus. Recanalisation may make reconstructive surgery easier and, finally, the results with initial thrombolysis are better than with surgery alone. The case against the motion is that expeditious surgery is in the patient's best interest, particularly in embolus, and when there is ischaemic damage to the limb. Furthermore, the reports of thrombolysis currently available are uncontrolled and do not demonstrate convincingly that the results of thrombolytic therapy are superior to surgery alone.

Calcium ion as intracellular messenger and cellular toxin

Ca2+ serves a nearly universal intracellular messenger function in cell activation, but excess Ca2+ is also a cellular toxin. The possibility of Ca2+ intoxication is minimized by an elaborate autoregulatory system in which changes in Ca2+ influx rate across the plasma membrane are rapidly compensated for by parallel changes in Ca2+ efflux rate. By this mean, cellular Ca2+ homestasis is maintained so that minimal changes in total cell calcium and cytosolic Ca2+ concentration occur during sustained Ca2(+)-mediated responses. Rather than a sustained increase in cytosolic Ca2+ concentration, it is the localized cycling of Ca2+ across the plasma membrane that is the critically important Ca2+ messenger during the sustained phase of cellular responses mediated via surface receptors linked to the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2). PIP2 hydrolysis gives rise to inositol(1,4,5)trisphosphate (IP3) and diacylglycerol (DAG). The IP3 acts to release Ca2+ from an intracellular pool, thereby causing a transient rise in cytosolic Ca2+ concentration. This transient Ca2+ signal activates calmodulin-dependent protein kinases transiently, and hence, causes the transient phosphorylation of a subset of cellular proteins that mediate the initial phase of the response. The DAG brings about the association of protein kinase C (PKC) with the plasma membrane where a receptor-mediated increase in Ca2+ cycling across the membrane regulates PKC activity. The sustained phosphorylation of a second subset of proteins by PKC mediates the sustained phase of the response. Hence, Ca2+ serves as a messenger during both phases of the cellular response, but its cellular sites of action, its mechanisms of generation, and its molecular targets differ during the initial and sustained phases of the response.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of Hermissenda K+ channels by cytoplasmic and membrane-associated C-kinase

Pharmacologic activation of endogenous protein kinase C (PKC) together with elevation of the intracellular Ca2+ level was previously shown to cause reduction of two voltage-dependent K+ currents (IA and ICa2+-K+) across the soma membrane of the type B photoreceptor within the eye of the mollusc Hermissenda crassicornis. Similar effects were also found to persist for days after acquisition of a classically conditioned response. Also, the state of phosphorylation of a low-molecular-weight protein was changed only within the eyes of conditioned Hermissenda. To examine the role of PKC in causing K+ current changes as well as changes of phosphorylation during conditioning (and possibly other physiologic contexts), we studied here the effects of endogenous PKC activation and exogenous PKC injection on phosphorylation and K+ channel function. Several phosphoproteins (20, 25, 56, and 165 kilodaltons) showed differences in phosphorylation in response to PKC activators applied to intact nervous systems or to isolated eyes. Specific differences were observed for membrane and cytosolic fractions in response to both the phorbol ester 12-deoxyphorbol 13-isobutyrate 20-acetate (DPBA) or exogenous PKC in the presence of Ca2+ and phosphatidylserine/diacylglycerol. Type B cells pretreated with DPBA responded to PKC injection with a persistent reduction of K+ currents. In the absence of DPBA, PKC injection also caused K+ current reduction only following Ca2+ loading conditions. However, the direct effect of PKC injection in the absence of DPBA was only to increase ICa2+-K+. According to a proposed model, the amplitude of the K+ currents would depend on the steady-state balance of effects mediated by PKC within the cytoplasm and membrane-associated PKC. The model further specifies that the effects on K+ currents of cytoplasmic PKC require an intervening proteolytic step. Such a model predicts that increasing the concentration of cytoplasmic protease, e.g., with trypsin, will increase K+ currents, whereas blocking endogenous protease, e.g., with leupeptin, will decrease K+ currents. These effects should be opposed by preexposure of the cells to DPBA. Furthermore, prior injection of leupeptin should block or reverse the effects of subsequent injection of PKC into the type B cell. All of these predictions were confirmed by results reported here. Taken together, the results of this and previous studies suggest that PKC regulation of membrane excitability critically depends on its cellular locus. The implications of such function for long-term physiologic transformations are discussed.

Early experience with B mode ultrasound mapping of the long saphenous vein prior to femorodistal bypass

B mode ultrasound was used to assess and map the long saphenous vein in 20 limbs prior to femorodistal bypass. The assessment was compared with operative findings. Eighteen of 19 adequate veins and 8 of 9 anatomical abnormalities or major divisions were correctly identified. B mode ultrasound allows accurate marking of the vein, facilitating dissection, alerts the surgeon to possible difficulties and is an ideal non-invasive technique for preoperative assessment of the long saphenous vein.

Comparison of the detection of breast carcinoma metastases by routine histological diagnosis and by immunohistochemical staining

The detection of metastases in 371 axillary lymph nodes by immunohistochemical staining and by routine histological examination was compared in the surgically removed tissue from 50 consecutive patients with breast carcinoma. The primary tumour and axillary lymph nodes were stained with three monoclonal antibodies directed against epitopes of the human milk fat globule (HMFG1; HMFG2; E29), and an anticytokeratin antibody (CAM 5.2), in a double-bridge immunoalkaline phosphatase staining technique. Metastases revealed by further sectioning through the tissue were identified before the immunohistological comparison. The use of immunohistochemical staining resulted in an increased detection of metastases in both infiltrating ductal carcinoma (13.1%) and infiltrating lobular carcinoma (37.5%), an overall increase of 17.3%. The follow-up data over a minimum period of 2 years is available for these patients.

Direct contact B-scan ultrasound in the diagnosis of solid breast masses

Our experience of breast ultrasound in the differentiation of benign and solid malignant breast masses indicates a specificity of 93% for carcinoma; 7% of cancers were regarded as benign. Eight of 89 proven fibroadenomas were considered possibly malignant. Typical, and overlapping, features are described, and the world literature is discussed. Whereas most previous workers have used a water-path technique, we employ direct contact B-scanning, which is quick, simple, and apparently at least as successful. The small group of solid masses where there is overlap between fibroadenoma and carcinoma needs further study; this might be helped by histological correlation with the ultrasound appearances of malignancy, the causes of which are still debated. The exclusion of a focal solid mass in a patient with a breast lump can reduce the biopsy rate.

Accuracy of aspiration cytology in the diagnosis of breast disease

The accuracy of fine needle aspiration cytology has been assessed in 480 consecutive breast lesions where definitive histology was later available. The results in terms of specificity and sensitivity have also been compared to mammography and clinical examination. With adequate smears aspiration cytology was 100 per cent specific with no false positive diagnosis. This compares with 15 false positive mammograms and 12 false positive diagnoses on clinical examination. Cytology was unsatisfactory in 36 per cent of benign lesions owing to poor cellularity of the sample but when considered with mammography and examination led to a reduction in biopsies for benign disease. A definitive cytological diagnosis of malignant tumours resulted in a reduction in frozen sections with a substantial saving of resources and improvement in patient counselling. No mastectomy was performed for benign disease.

The prognostic value of the monoclonal antibodies HMFG1 and HMFG2 in breast cancer

The monoclonal antibodies HMFG1 and HMFG2 identify antigens of the milk fat globule membrane which are also found on breast epithelial cells. Immunohistochemical staining was performed using both antibodies on formalin fixed, paraffin embedded sections of 93 breast carcinoma, 36 histologically benign lesions and 29 histologically normal breast tissue blocks. In both normal and benign breast disease the staining was largely extracellular whilst in malignant tissue the staining was variable and often intracellular. Nine carcinomas did not stain with either antibody. The staining patterns of malignant tissues were graded and no correlation was found between the grades and survival or indices of prognosis, (the oestrogen receptor status, Bloom's grade and the presence or absence of metastases to the axillary nodes.) This study indicates that with the present methods available for grading staining patterns, although of diagnostic value, these monoclonal antibodies are unlikely to assist in determining either the degree of tumour differentiation or prognosis in breast carcinoma.

Assessment of a scoring scheme for the preoperative diagnosis of breast lumps

The value and accuracy of a scoring system applied to clinical examination, aspiration cytology and mammography has been assessed in the diagnosis of 224 consecutive 'new' patients attending a breast clinic with a breast lump. In 72 of 99 patients with breast cancer (80%) the scores were high enough to allow definitive surgery without formal histology; all were subsequently confirmed as breast carcinomas. Cytology proved the most accurate investigation with no false positives and a correct diagnosis in 146 of 148 adequate specimens (98.6%). This system reduced the frozen section rate by 74% and allowed for a more appropriate counselling of patients prior to mastectomy.

Identification of a novel hepatic calcium binding protein

Calcium binding activity in the 100,000 X g supernatant of bovine liver has been isolated by a procedure involving DEAE cellulose and Sephadex G-100 chromatography. In addition to calmodulin, two new high affinity calcium binding proteins have been identified. On gel filtration chromatography these proteins migrate with apparent molecular weights of 83,700 and 51,400; whereas by sodium dodecyl sulfate polyacrylamide gel electrophoresis, the two proteins migrate identically with Mr 63,000. In the presence of millimolar Mg2+, both proteins bind up to one mol Ca2+/mol protein. Half-maximal binding occurs at approximately 0.1 microM Ca2+. Amino acid compositional analysis reveals that both proteins are acidic, and contain about 40% glx and asx. Peptide mapping procedures suggest that these proteins may be highly homologous or multiple forms of a single protein. The results show the existence of calcium binding protein(s) other than calmodulin in hepatic cytosol.

Detection of yeast ribosomal RNA sequences in E. coli infected with hybrid bacteriophage

Yeast ribosomal DNA was inserted into Escherichia coli on a bacteriophage vector and the host cell RNA was then extracted and analyzed for the presence of yeast ribosomal RNA sequences. RNA complementary to yeast rDNA was detected by hybridization. The transcription of yeast rDNA was found to be independent of phage RNA synthesis and to occur on the same DNA strand as rRNA transcription in yeast. However, hybridization to restriction fragments of yeast rDNA suggested that the RNA species detected in E. coli differ somewhat from authentic yeast rRNA.