Metabolic-associated fatty liver disease and risk of esophagogastric cancer: a systematic review and meta-analysis

INTRODUCTION

Metabolic-associated fatty liver disease (MAFLD) has been found to be strongly linked to several diseases. Although previous studies have explored the association between MAFLD and extrahepatic cancers, research on the relationship between MAFLD and gastric carcinoma (GC) and esophageal carcinoma (EC) is relatively scarce and requires updating. Therefore, the objective of this study is to conduct a comprehensive investigation into the association between MAFLD and GC or EC.

MATERIAL AND METHODS

We conducted a comprehensive search for relevant studies published up to 5 August 2022, using the PubMed, Embase and Web of Science databases. To estimate the risk ratio (RR) and the 95% confidence interval (CI), we employed a random-effects model. We also conducted subgroup analyses based on study characteristics. The protocol for this systematic review is registered in the Prospero database under the registration number CRD42022351574.

RESULTS

Our analysis included eight eligible studies, comprising a total of 8 629 525 participants. We found that the pooled RR values for the risk of GC in patients with MAFLD were 1.49 (95%CI: 1.17-1.91), whereas the pooled RR values for the risk of EC in patients with MAFLD were 1.76 (95%CI: 1.34-2.32).

CONCLUSIONS

Based on our meta-analysis, we conclude that there is a significant association between the presence of MAFLD and the development of GC and EC.

Unsuppressed Striatal Activity and Genetic Risk for Schizophrenia Associated With Individual Cognitive Performance Under Social Competition

BACKGROUND AND HYPOTHESIS

Social competition affects human behaviors by inducing psychosocial stress. The neural and genetic mechanisms of individual differences of cognitive-behavioral response to stressful situations in a competitive context remain unknown. We hypothesized that variation in stress-related brain activation and genetic heterogeneity associated with psychiatric disorders may play roles towards individually differential responses under stress.

STUDY DESIGN

A total of 419 healthy subjects and 66 patients with schizophrenia were examined functional magnetic resonance imaging during working memory task including social competition stressors. We explored the correlation between stress-induced brain activity and individual working memory performance. The partial least squares regression was performed to examine the genetic correlates between stress-related activity and gene expression data from Allen Human Brain Atlas. Polygenic risk score (PRS) was used to assess individual genetic risk for schizophrenia.

STUDY RESULTS

Greater suppression of bilateral striatal activity was associated with better behavioral improvement in working memory manipulation under social competition (left: rPearson = -0.245, P = 4.0 × 10-6, right: rPearson = -0.234, P = 1.0 × 10-5). Genes transcriptionally related to stress-induced activation were linked to genetic risk for schizophrenia (PFDR < 0.005). Participants with decreased accuracy under social competition exhibited higher PRS of schizophrenia (t = 2.328, P = .021). Patients with schizophrenia showed less suppressed striatal activity under social stress (F = 13.493, P = 3.5 × 10-4).

CONCLUSIONS

Striatal activity change and genetic risk for schizophrenia might play a role in the individually behavioral difference in working memory manipulation under stress.

The Systemic Immune-Inflammation Index May Be a Novel and Strong Marker for the Accurate Early Prediction of Acute Kidney Injury in Severe Acute Pancreatitis Patients

OBJECTIVE

This research was performed to investigate the correlation between acute kidney injury (AKI) and systemic immune-inflammation index (SII) in severe acute pancreatitis (SAP) patients.

METHODS

The study included 218 SAP patients from Chongqing Jiangjin Center Hospital during January 2016 to October 2020. The SII was defined as platelet × neutrophil/lymphocyte ratio. After univariate analysis, logistic regression analysis was used for analyzing independent risk factors of AKI in SAP patients. Receiver operating characteristic (ROC) curve was used for analyzing the prognostic value of the SII.

RESULTS

AKI occurred in 74 cases and its incidence rate was 33.9%. The median SII value of AKI patients was higher than that of patients without AKI. After multivariate analysis, SII, age, triglyceride (TG), neutrophil ratio (NEU-R), C-reactive protein (CRP), aspartate aminotransferase (AST), and serum albumin (ALB) were independent predictors of AKI. Serum ALB was an independent protective factor. The optimum threshold truncation value of SII was 2880.1*10^9/L. Compared with other inflammatory factors, SII had a better prediction efficiency.

CONCLUSION

The SII, TG, NEU-R, CRP, and ALB were significant independent predictors of AKI in SAP patients. Serum TG, NEU-R, CRP, and SII were risk factors. Serum ALB was a protective factor. The SII may be a novel, simple, and strong marker for the accurate early prediction of AKI in SAP patients.

[Effect of electrode array type and insertion technique on the insertion force: in vitro cochlear model study]

Objective: To investigate the effect of insertion technique and electrode array type on the insertion force of electrode array, and to provide a basis for further optimizing electrode design and facilitating mini-invasive electrode insertion. Methods: Three types of electrode array from Nurotron (Standard Electrode, Slim-medium Electrode, Slim-long Electrode) were studied. from July 2019 to December 2019. These electrode arrays were inserted into the phantom models of the cochlea, manually or robot-assisted(medium speed and low speed). The real-time force during electrode array insertion was recorded by ATI Nano 17 Ti sensors and was analyzed by accessory software. Origin 2020b software was used for statistical processing. Results: The insertion force of all electrode arrays progressively increased with the insertion depth. With the manual technique, the peak force of slim-medium electrode insertion was significantly smaller than that of the standard electrode insertion((71.0±16.6) mN vs (140.9±52.7) mN, Z=3.683, P<0.01), and the peak force of the slim-long electrode insertion was between the peak force of standard electrode and slim-medium electrode(P>0.05). No difference was found in the force variation of insertion among the three electrodes(P>0.05). With medium-speed and low-speed robotic assistance, the peak force characteristics of three electrodes were similar to those with the manual technique, but the force variation of standard electrode insertion ((83.9±9.7) mN/s) at medium speed was significantly larger than that of the slim-long electrode insertion ((69.2±4.0)mN/s), and the force variation of the standard electrode insertion at low speed was significantly greater than the other two electrodes. For the same electrode, robot-assisted insertion presented significantly lower peak force and force variation than manual insertion for each type of electrode array. But there was no difference in the peak force and force variation between two-speed levels of robot assistance (P>0.05). Conclusions: The insertion force of the electrode array will be lower when a slim electrode array or robot technique is applied. Long electrode array might make manual insertion difficult or less precise. Robot assistance has advantage on force control during electrode array insertion.

[Clinical features of 141 fatal cases of coronavirus disease in Jinyintan Hospital in Wuhan, China]

Objective: To describe the epidemiological characteristics and clinical features of patients with fatal coronavirus disease (COVID-19), in order to provide evidence for clinical diagnosis and treatment. Methods: In this retrospective study, we analyzed data on 141 fatal cases of confirmed COVID-19 that occurred among patients in Jinyintan Hospital in Wuhan, China, from January 20 to March 6, 2020. We analyzed their epidemiological characteristics, clinical and radiological features, laboratory results, and treatment. Results: Of the 141 patients (49 females, 92 males), the median age was 77 years (range: 24-92 years). The most likely source of exposure included the Huanan seafood market (n=3, 2%), family members (n=6, 4%), and hospital-acquired infection (n=8, 6%). The remaining 116 patients (72%) had no known source of exposure. Of the patients, 101 (72%) had chronic diseases. The most common comorbidities were hypertension, diabetes and coronary heart disease. The most common clinical manifestations were fever (n=121, 85%), dry cough (n=77, 54%), shortness of breath (n=23, 16%), and chest pain (n=15, 10%). Less common clinical manifestations included fatigue (n=7, 4%), headache (n=3, 2%), disorders of consciousness (n=2, 1%), diarrhea (n=2, 1%) and lumbago (n=1, 0.7%). In terms of laboratory tests, the absolute value of lymphocytes in most patients was reduced (n=132, 94%), but C-reactive protein (n=141, 100%), procalcitonin(n=121, 89%), serum amyloid (n=140, 99%) were significantly increased. The most common findings on imaging of the lungs were bilateral multiple mottling and ground-glass opacity (n=101, 72%), mainly in the lower lobes (n=15, 10%), with lesions being more common on the right. Other imaging findings included diffuse consolidation (n=4, 3%), ground-glass opacity and consolidation (n=20, 14%), and pneumothorax (n=1, 0.7%). All patients were treated with antibiotics and antiviral drugs. Other treatments included immunoglobulin (n=49, 35%), corticosteroids (n=45, 32%), continuous renal replacement therapy (n=24, 17%), and extracorporeal membrane oxygenation (n=12, 9%). All patients were treated with oxygen therapy. The mode of administration included invasive mechanical ventilation (n=61, 43%), noninvasive mechanical ventilation (n=65, 46%), and nasal catheter oxygen inhalation (n=15, 11%). The direct causes of death were acute respiratory distress syndrome (n=90, 64%), multiple organ failure (n=24, 17%), sudden cardiac arrest (n=11, 8%), viral myocarditis (n=8, 5%), acute myocardial infarction (n=4, 3%), cerebrovascular accident (n=3, 2%), and acute gastrointestinal bleeding (n=1, 0.7%). Conclusions: Risk factors for death due to COVID-19 included older age, male sex, and the presence of comorbidities. The most common direct causes of death were acute respiratory distress syndrome, multiple organ failure, sudden cardiac arrest, and viral myocarditis.

A Scoring System for Surgical Site Infection after Pancreaticoduodenectomy Using Clinical Data

Object: To analyze the factors influencing surgical site infection (SSI) after pancreaticoduodenectomy and to establish a scoring system for predicting such infections. Methods: Patients who underwent pancreaticoduodenectomy in the Department of Hepatobiliary Surgery of the Second Affiliated Hospital of Chongqing Medical University from January 2015 to March 2019 were divided randomly into a model group and a test group in a proportion of 3:1. According to whether an SSI occurred after operation, the model group was divided into an incision-infection group and a non-infection group. Univariable analysis and multivariable regression analysis were used to analyze factors related to post-operative incision infection and to establish a clinical predictive scoring system. The scoring system was evaluated for the test group. Results: A total of 236 patients, 177 in the model group and 59 in the test group, were included. In the model group, univariable and logistic regression analysis showed that tumor nature (benign versus malignant), post-operative albumin concentration, pancreatic fistula formation, post-operative cough, and peri-operative blood transfusion were the independent risk factors for incision infection. Then we established a clinical predictive scoring system. In the test group, the area under the receiver operator characteristic curve of the system was 0.768 (p < 0.001, with sensitivity = 59.1% and specificity = 94.6%). Conclusion: The scoring system had good clinical prediction ability and high specificity, so it was worth using in the clinic.

Nonalcoholic fatty liver disease and mortality from all causes, cardiovascular disease, and cancer: a meta-analysis

Whether nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of mortality remains controversial. The present study aimed to clarify this issue. A systematic search of PubMed and Embase was conducted through October 2018. Studies providing risk estimates of NAFLD and mortality were included. A random-effects model was employed to calculate summary risk estimates. Subgroup analyses were performed to identify potential effect modifiers. Fourteen studies, involving 498501 subjects and 24234 deaths, were included. Patients with NAFLD were found to be at an elevated risk of all-cause mortality compared with those without [hazard ratio (HR) = 1.34; 95% confidence interval (CI) 1.17-1.54)]. The significantly positive association between NAFLD and all-cause mortality could not be modified by age, sex, follow-up duration, and adjustment for body mass index, diabetes, smoking or hypertension (all Pinteraction > 0.05), and remained in sensitivity analyses. No significant associations of NAFLD with CVD (HR = 1.13; 95% CI 0.92-1.38) and cancer (HR = 1.05; 95% CI 0.89-1.25) mortality were found. In conclusion, NAFLD is a predictor of increased all-cause mortality but not CVD and cancer mortality. These findings have important implications for decision making in public health and clinical practice, and highlight the urgency of developing effective treatments for NAFLD.

Risk Assessment of Laparoscopic Cholecystectomy in Liver Cirrhotic Patients with Clinically Significant Portal Hypertension: A Retrospective Cohort Study

Objective: This study was aimed to evaluate the correlation between clinically significant portal hypertension (CSPH) and postoperative complications and risk predictors of postoperative complications. Methods: The retrospective study was conducted to identify the effect. The cirrhotic patients were divided into two groups, those with or without CSPH. The intraoperative and postoperative conditions were evaluated. Multivariate logistic regression analysis was performed to identify potential risk predictors for postoperative complications in cirrhotic patients with CSPH. Results: The cirrhotic patients with CSPH who underwent laparoscopic cholecystectomy (LC) had postoperative hospitalization than the patients without CSPH. However, the incidence of postoperative complications between two groups showed no significant difference. The results of multivariate analysis showed that male, gallbladder wall >3 mm, size of stones ≥1 cm, scores of Model for end-stage liver disease (MELD) ≥10, and operation time >60 minutes were the potential risk predictors for postoperative complications. Conclusions: CSPH did not increase the incidence of postoperative complications in cirrhotic patients who underwent LC, but increased conversion rate and prolonged postoperative hospitalization. Furthermore, our study showed that gender, sizes of gallbladder wall and stones, scores of MELD, and operation time were the important postoperative risk predictors for cirrhotic patients with CSPH.

Shenfu Injection Attenuates Bile Duct Injury in Rats with Acute Obstructive Cholangitis

Background: We investigated the effect of Shenfu injection (SFI) in Wistar rats with acute obstructive cholangitis (AOC) and considered the possible molecular mechanisms of the effects. Methods: The 96 rats were divided randomly into three groups. In one group, the common bile duct was subjected to ligation (BDL), and 0.2 mL of saline was injected into the proximal bile ducts. To create AOC, again, the common bile duct was ligated, and 0.2 mL of lipopolysaccharide (LPS)) (2 mg/mL) was injected into the proximal ducts. In the Shenfu injection (SFI) group, the material (10 mg/kg) was injected into the tail vein 2 hours before induction of AOC. The hepatic histopathologic changes were observed under a light microscope. The endotoxin, tumor necrosis factor-α (TNF-α), alanine transaminase (ALT), and total bilirubin (TB) concentrations in the serum were measured at different time points (0, 4, 8, and 16 hours) after ligation. The expression of nuclear transcription factor-κB (NF-κB) and CD14 in Kupffer cells also was analyzed at different times by Western blotting. Results: The TNF-α, ALT, and TB concentrations in the serum and the expression of CD14 and NF-κB in Kupffer cells were significantly higher in the SFI group than in the BDL group, but all were significantly lower than in the AOC group. Compared with the AOC group, the edema of cholangiocytes was alleviated in the SFI group, and the infiltration of inflammatory cells around cholangiocytes was reduced. Conclusion: Shenfu injection significantly alleviated bile duct injury. The potential mechanism may be associated with inhibition of CD14 expression and prevention of NF-κB activation in Kupffer cells.

[Factors of hearing preservation in acoustic neuroma surgery]

Over the past 50 years, the focus of acoustic neuroma surgery has shifted from low mortality and tumor resection to retention of neurological function. Hearing preservation is another point in addition to facial nerve function preservation. Hearing preservation rates overall ranged from 2% to 93% in recent studies. Characteristics such as approach, pre-operative neurological function, tumor size, nerve of origin and fundal fluid of the internal auditory canal have been reported as possible influencing factors. This review provides a summary of recent studies and describes the prognostic factors that predict hearing preservation.

[The exploration of gene promoter methylation profiling in nasal polyp]

Objective:To explore the gene promoter methylation profiles of nasal polyp, and to analysis the promoter methylation differences between the nasal polyp and the normal nasal mucosa.Method:Total DNA of the nasal polyp tissues and normal nasal mucosa were extracted. After immunoprecipitation and whole genome amplification, the DNA was labeled with Cy3/5 and hybridized in NimbleGen hybridization chamber. For array hybridization, Roche Nimblegen CpG Promoter array was used. The slides were scanned using the Axon GenePix 4000B microarray scanner. The different genes were analyzed through pathway and verified by Real-time PCR.Result:3010 genes were found to have promoter hypermethylation in normal nasal mucosa or nasal polyp.2,62%(79/3010) of the genes had promoter hypermethylation in all the nasal polyps, which were negative in normal nasal mucosa.10.66%(321/3010) of the genes had promoter hypermethylation in normal nasal mucosa, which were negative in all the nasal polyps. Three pathways were found in the promoter hypermethylation of the nasal polyps. Fourteen pathways were found in the negative hypermethylation of the nasal polyps.Conclusion:Genes promoter methylation plays an important role in the development of nasal polyps, and the gene promoter methylation profiling may yield new some clues on the mechanism of nasal polyps.

[Personal dose monitoring of radiation workers in medical institutions at the municipal level and below in a city from 2011 to 2014]

Objective: To determine the personal dose level of radiation workers in medical institutions at the municipal level and below in a city, and to provide a scientific support for strengthening the radiation protection in the city's medical institutions. Methods: Information of the successful applicants for the "Radiation Worker Permit" from 174 medical institutions at the municipal level and below was collected from October 1, 2011 to December 31, 2014. The annual effective dose was calculated based on the personal dose monitoring report, and indicators including sex, permit application time, hospital level, type of occupational radiation, length of radiation work, blood test, and micronucleated lymphocyte rate were analyzed. Results: Of the 1 143 radiation worker permit applications submitted by medical institutions the municipal level and below in this city from 2011 to 2014, 1 123 provided at least one personal dose monitoring report. The annual effective dose of the radiation workers was 0-4.76 mSv (mean 0.31±0.40 mSv) , and the collective annual effective dose was 351.96 mSv. The annual effective dose was significantly different between radiation workers with different times of permit application, hospital levels, and types of occupational radiation (P<0.05) . Interventional radiology workers had the highest annual effective dose (0.63 mSv) , and annual effective dose was significantly different between interventional radiology workers with different lengths of radiation work (H=10.812, P<0.05) . Conclusion: The personal radiation dose of radiation workers in medical institutions at the municipal level and below in this city is maintained at a relatively low level, suggesting that the occupational environment is relatively safe for these workers. However, more focus should be placed on clinical interventional radiology workers.

[The exploration of VEGF-B methylation in the nasal polyp]

Objective:The objective of this study is to investigate the methylation status of vascular endothelial cell growth factor B (VEGF-B) gene and to indentify the roles in pathogenesis,development and classification of nasal polyps.Method:The methylation status of VEGF-B gene of 28 nasal polyp tissues and 12 samples of inferior turbinate tissues were detected by methylationspecific-polymerase chain reaction (MS-PCR) and gene sequencing.Result:There was significant statistic diference between nasal polyp tissue group and control group (χ ²=4.096,P<0.05). The results of gene sequencing suggest that the VEGF-B gene promoter were hypomethylation status in the nasal polyps.Conclusion:Methylation status of VEGF-B promoter may play an important role in the pathogenetic mechanism of nasal polyps.

Percutaneous Transhepatic Gallbladder Drainage Combined with Laparoscopic Cholecystectomy: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To investigate the clinical effect of the laparoscopic cholecystectomy (LC) after percutaneous transhepatic gallbladder drainage (PTGD) in elder acute cholecystitis.

METHODS

The Cochrane Library, PubMed, China National Knowledge Infrastructure (CNKI), VIP, and Wanfang Databases were searched for randomized controlled trials (RCTs) on LC after PTGD in elder acute cholecystitis published from 1970 to July 2017. Two researchers selected RCTs, extracted data, and evaluated methodological quality independently, and RevMan 5.3 software was used for the meta-analysis. The chi-square test was used for heterogeneity analysis of RCTs included, and the funnel plots were used to evaluate publication bias.

RESULTS

A total of 9 RCTs with 1000 patients were included in this analysis. Compared with the direct LC Group, the PTGD Group has significant better effect in operative duration (minutes) [standard mean difference (SMD) = -1.37, 95% confidence interval (95% CI): -2.52 to -0.22, P = .02], the amount of intraoperative bleeding (mL) (SMD = -1.38, 95% CI: -2.11 to -0.65, P = .0002), conversion rate to laparotomy (%) [odds ratio (OR) = 0.16, 95% CI: 0.08 to 0.31, P < .00001], postoperative complication morbidity (%) (OR = 0.29, 95% CI: 0.17 to 0.51, P < .0001), and postoperative hospital stay (days) (SMD = -1.26, 95% CI: -1.94 to -0.59, P = .0003). The funnel plots were slightly asymmetric, which suggested the presence of publication bias.

CONCLUSION

The PTGD before scheduled LC can effectively not only shorten operative duration, intraoperative bleeding less, and postoperative hospital stay but also decrease the rate to laparotomy and postoperative complication morbidity in elder acute cholecystitis, and it is recommended to be regarded as the preferred therapy of the elder patients.

[A combination use of endoscope and microscope in cerebral pontine angle surgery]

Objective: To evaluate the application of combination use of microscope and endoscope in cerebral pontine angle (CPA) surgery. Methods: A total of 72 patients undergone lateral skull base surgeries via endoscope under microscopic control from January 2006 to January 2015 was reviewed respectively. The patients including 35 males and 37 females were composed of 22 cases of vestibular swannnomas, 45 cases of cranial neuropathy and 5 cases of CPA chelesteatoma. Twenty cases of vestibular swannnomas, 15 cases of cranial neuropathy and 2 cases of CPA chelesteatoma undergone the surgery via retrosigmoid approach, while other cases undergone the surgery via retrolabyrinthine approach. Surgical procedures were accomplished under the control of microscope and different angular endoscope with imaging fusion. The surgical results were evaluated according to subjective and objective criteria, and all patients were followed up for 15 years. Results: The symptoms was disappeared in the cranial neuropathy patients, without facial paralysis, complication of other nerves or hearing loss. Twenty-two patients with vestibular schwannomas got total tumor removal without facial palsy or neurological deficits; useful hearing was preserved in 16 of 22 patients (72.7%), and no tumor recurrence was found during 1-5 years follow-up. There was also no facial palsy or other complications in 5 cases of CPA chelesteatoma, which gained completely surgical removal; useful hearing was preserved in 3 of 5 cases of these patients and no recurrence was occurred during 1-1.5 years follow-up. Conclusions: A combination use of endoscope and microscope could combine advantages and avoid disadvantages of two techniques. It can provide better exposure with minimal invasion in CPA surgery, and is especially applicable in surgery for cranial neuropathy, vestibular schwannoma and CPA cholesteatoma, which should be performed through retrosigmoid approach and retrolabyrinthine approach.

Changes in rumen protozoal community by condensed tannin fractions of different molecular weights from a Leucaena leucocephala hybrid in vitro

AIMS

To evaluate the effects of condensed tannins (CTs) fractions of differing molecular weights (MWs) from a Leucaena leucocephala hybrid-Rendang on the rumen protozoal community in vitro.

METHODS AND RESULTS

The effects of unfractionated CTs (F0) and CT fractions of different MWs (F1 > F2 > F3 > F4 > F5) on protozoal population and community were evaluated in vitro using rumen microbes and ground guinea grass as the substrate. Higher-MW CT fractions F1 and F2 significantly (P < 0·05) decrease the number of ciliate protozoa. The real-time PCR analysis showed that the total protozoa was significantly (P < 0·05) lower in F0 and all CTs with fractions F1 and F2 having the lowest value. High-throughput sequencing of the partial 18S rRNA gene showed that the genus Entodinium significantly (P < 0·05) decreased with increasing MWs of CT, whereas Anoplodinium-Diplodinium were significantly (P < 0·05) increased. Inclusion of the highest MW CT fraction F1 decreased the relative abundance of the minor genera such as Eudiplodinium and Polyplastron compared to the control and CT fractions F2-F5.

CONCLUSION

CTs of differing MWs could reduce and alter the rumen protozoa population in vitro. This effect was more pronounced for higher-MW CTs.

SIGNIFICANCE AND IMPACT OF THE STUDY

The high MW CTs should be considered as a feed supplement in the ruminant diet to reduce the protozoal population which are known to be associated with methanogens as a means to mitigate methane production in the rumen.

Hyperphagia in male melanocortin 4 receptor deficient mice promotes growth independently of growth hormone

KEY POINTS

Loss of function of the melanocortin 4 receptor (MC4R) results in hyperphagia, obesity and increased growth. Despite knowing that MC4Rs control food intake, we are yet to understand why defects in the function of the MC4R receptor contribute to rapid linear growth. We show that hyperphagia following germline loss of MC4R in male mice promotes growth while suppressing the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. We propose that hyperinsulinaemia promotes growth while suppressing the GH-IGF-1 axis. It is argued that physiological responses essential to maintain energy flux override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth.

ABSTRACT

Defects in melanocortin-4-receptor (MC4R) signalling result in hyperphagia, obesity and increased growth. Clinical observations suggest that loss of MC4R function may enhance growth hormone (GH)-mediated growth, although this remains untested. Using male mice with germline loss of the MC4R, we assessed pulsatile GH release and insulin-like growth factor-1 (IGF-1) production and/or release relative to pubertal growth. We demonstrate early-onset suppression of GH release in rapidly growing MC4R deficient (MC4RKO) mice, confirming that increased linear growth in MC4RKO mice does not occur in response to enhanced activation of the GH-IGF-1 axis. The progressive suppression of GH release in MC4RKO mice occurred alongside increased adiposity and the progressive worsening of hyperphagia-associated hyperinsulinaemia. We next prevented hyperphagia in MC4RKO mice through restricting calorie intake in these mice to match that of wild-type (WT) littermates. Pair feeding of MC4RKO mice did not prevent increased adiposity, but attenuated hyperinsulinaemia, recovered GH release, and normalized linear growth rate to that seen in pair-fed WT littermate controls. We conclude that the suppression of GH release in MC4RKO mice occurs independently of increased adipose mass, and is a consequence of hyperphagia-associated hyperinsulinaemia. It is proposed that physiological responses essential to maintain energy flux (hyperinsulinaemia and the suppression of GH release) override conventional mechanisms of pubertal growth to promote the storage of excess energy while ensuring growth. Implications of these findings are likely to extend beyond individuals with defects in MC4R signalling, encompassing physiological changes central to mechanisms of growth and energy homeostasis universal to hyperphagia-associated childhood-onset obesity.

Molecular Weight, Protein Binding Affinity and Methane Mitigation of Condensed Tannins from Mangosteen-peel (Garcinia mangostana L)

The objectives of this study were to determine the molecular weight of condensed tannins (CT) extracted from mangosteen (Garcinia mangostana L) peel, its protein binding affinity and effects on fermentation parameters including total gas, methane (CH₄) and volatile fatty acids (VFA) production. The average molecular weight (M_w) of the purified CT was 2,081 Da with a protein binding affinity of 0.69 (the amount needed to bind half the maximum bovine serum albumin). In vitro gas production declined by 0.409, 0.121, and 0.311, respectively, while CH₄ production decreased by 0.211, 0.353, and 0.549, respectively, with addition of 10, 20, and 30 mg CT/500 mg dry matter (DM) compared to the control (p<0.05). The effects of CT from mangosteen-peel on in vitro DM degradability (IVDMD) and in vitro N degradability was negative and linear (p<0.01). Total VFA, concentrations of acetic, propionic, butyric and isovaleric acids decreased linearly with increasing amount of CT. The aforementioned results show that protein binding affinity of CT from mangosteen-peel is lower than those reported for Leucaena forages, however, the former has stronger negative effect on IVDMD. Therefore, the use of mangosteen-peel as protein source and CH₄ mitigating agent in ruminant feed requires further investigations.

Cerebral Inefficient Activation in Schizophrenia Patients and Their Unaffected Parents during the N-Back Working Memory Task: A Family fMRI Study

Background

It has been suggested that working memory deficits is a core feature of symptomatology of schizophrenia, which can be detected in patients and their unaffected relatives. The impairment of working memory has been found related to the abnormal activity of human brain regions in many functional magnetic resonance imaging (fMRI) studies. This study investigated how brain region activation was altered in schizophrenia and how it was inherited independently from performance deficits.

Method

The authors used fMRI method during N-back task to assess working memory related cortical activation in four groups (N = 20 in each group, matching task performance, age, gender and education): schizophrenic patients, their unaffected biological parents, young healthy controls for the patients and older healthy controls for their parents.

Results

Compared to healthy controls, patients showed an exaggerated response in the right dorsolateral prefrontal cortex (brodmann area [BA] 46) and bilateral ventrolateral prefrontal cortex, and had reduced activation in bilateral dorsolateral prefrontal cortex (BA 9). In the conjunction analysis, the effect of genetic risk (parents versus older control) shared significantly overlapped activation with effect of disease (patients versus young control) in the right middle frontal gyrus (BA 46) and left inferior parietal gyrus (BA 40).

Conclusions

Physiological inefficiency of dorsal prefrontal cortex and compensation involvement of ventral prefrontal cortex in working memory function may one physiological characteristics of schizophrenia. And relatively inefficient activation in dorsolateral prefrontal cortex probably can be a promising intermediate phenotype for schizophrenia.

Obesity and sex influence insulin resistance and total and multimer adiponectin levels in adult neutered domestic shorthair client-owned cats

In this study, we estimated insulin sensitivity and determined plasma concentrations of total-, low-molecular-weight (LMW), and high-molecular-weight (HMW) adiponectin and leptin in 72 domestic shorthair, neutered, client-owned cats. Glucose tolerance was assessed with an intravenous glucose tolerance test and body fat percentage (BF%) was measured with dual-energy x-ray absorptiometry. Total adiponectin was measured with 2 different ELISAs. Low-molecular-weight and HMW adiponectin plasma concentrations were determined by Western blot analysis after sucrose-gradient velocity centrifugation, and the adiponectin multimer ratio [SA = HMW/(HMW + LMW)] was calculated. Differences in glucose tolerance, leptin, total adiponectin, and multimer ratio among lean (BF% <35; n = 26), overweight (35 <BF% <45; n = 28), and obese (BF% >45; n = 18) cats as well as between male (n = 34) and female (n = 38) neutered cats were evaluated by linear regression and 2-way ANOVA. Sex and age were included as covariates for analysis of BF%, whereas BF%, fat mass, and lean body mass were covariates for analysis of sex differences. Increased BF% was negatively correlated with multimer ratio (SA, r = -45; P < 0.002), whereas no differences were found in total adiponectin concentrations among BF% groups (P > 0.01). Male cats had indices of decreased insulin tolerance and significantly lower total adiponectin concentrations than did female cats (mean ± SEM, 3.7 ± 0.4 vs 5.4 ± 0.5 μg/mL; P < 0.02). Altered SAs could contribute to an obesity-associated decreasing glucose tolerance in cats, and low total adiponectin concentrations may relate to increased risk of diabetes mellitus in neutered male cats.

Hypothalamic distribution of somatostatin mRNA expressing neurones relative to pubertal and adult changes in pulsatile growth hormone secretion in mice

The age-associated decline in growth hormone (GH) secretion may be a consequence of the reduction in the number of GH-releasing hormone (GHRH) positive neurones. However, it remains unclear whether an alteration in the number or distribution of somatostatin (SST) neurones contributes to this change. In the present study, we characterised the role of SST in modulating the change in pulsatile GH secretion in male C57Bl/6J mice throughout puberty and into early adulthood. We assessed pulsatile GH secretion in mice at 4, 8 and 16 weeks of age. These ages correspond to early pubertal, early adulthood and adulthood, respectively. We show an elevation in peak, total and pulsatile GH secretion coinciding with periods of rapid linear growth. Using in situ hybridisation and morphometric methods, we mapped the distribution of Sst mRNA expression within the mouse brain relative to this change in pulsatile GH secretion. The results obtained show that altered pulsatile GH secretion in male mice from 4-16 weeks of age does not coincide with a significant change in the number of Sst mRNA expressing neurones or an abundance of Sst mRNA expression throughout the arcuate nucleus (ARC) and periventricular nucleus (PeV). Rather, we observed a progressive decline in Sst mRNA expressing neurones within subnuclei of the paraventricular nucleus at this time. We conclude that structural changes in Sst expression within the PeV and ARC may not reflect the observed decline in pulsatile GH secretion in mice from puberty into early adulthood.

Epistatic interactions of AKT1 on human medial temporal lobe biology and pharmacogenetic implications

AKT1 controls important processes in medial temporal lobe (MTL) development and plasticity, but the impact of human genetic variation in AKT1 on these processes is not known in healthy or disease states. Here, we report that an AKT1 variant (rs1130233) previously associated with AKT1 protein expression, prefrontal function and schizophrenia, affects human MTL structure and memory function. Further, supporting AKT1's role in transducing hippocampal neuroplasticity and dopaminergic processes, we found epistasis with functional polymorphisms in BDNF and COMT--genes also implicated in MTL biology related to AKT1. Consistent with prior predictions that these biologic processes relate to schizophrenia, we found epistasis between the same AKT1, BDNF and COMT functional variants on schizophrenia risk, and pharmacogenetic interactions of AKT1 with the effects on cognition and brain volume measures by AKT1 activators in common clinical use--lithium and sodium valproate. Our findings suggest that AKT1 affects risk for schizophrenia and accompanying cognitive deficits, at least in part through specific genetic interactions related to brain neuroplasticity and development, and that these AKT1 effects may be pharmacologically modulated in patients.

The decline in pulsatile GH secretion throughout early adulthood in mice is exacerbated by dietary-induced weight gain

The transition between puberty and adulthood is accompanied by a slowing in linear growth. Although GH is a key factor that drives somatic development into adulthood, early adulthood coincides with a reduction in circulating levels of GH. To this extent, a pathological decline in postpubertal GH secretion is detrimental to attainment of peak lean muscle mass and bone mass and promotes adiposity and increases susceptibility to the development of obesity in adulthood. Here we characterized pulsatile GH secretion in C57BL/6J mice at 12 and 16 wk of age. Deconvolution analysis of these measures reveals a reduction in pulsatile GH secretion between 12 and 16 wk of age. Dietary intervention with high-fat feeding at 8 wk of age results in a significant increase in adiposity, the development of glucose intolerance, and hyperinsulinemia. We show the exacerbation of the age-associated decline in pulsatile GH secretion in high-fat-fed mice after 4 wk of dietary intervention (at 12 wk of age), and a further suppression of pulsatile GH secretion by 8 wk of dietary intervention (at 16 wk of age). Suppressed pulsatile secretion of GH did not coincide with an elevation in circulating free fatty acids. Rather, we observed increased hepatic triglyceride content and an eventual decrease in circulating levels of IGF-I. Given the established role of GH in maintaining healthy aging, we anticipate that an advancing of the age-associated decline in pulsatile GH secretion as a consequence of dietary-induced weight gain may have long-term ramifications on adult health.

Investigation of anatomical thalamo-cortical connectivity and FMRI activation in schizophrenia

The purpose of this study was to examine measures of anatomical connectivity between the thalamus and lateral prefrontal cortex (LPFC) in schizophrenia and to assess their functional implications. We measured thalamocortical connectivity with diffusion tensor imaging (DTI) and probabilistic tractography in 15 patients with schizophrenia and 22 age- and sex-matched controls. The relationship between thalamocortical connectivity and prefrontal cortical blood-oxygenation-level-dependent (BOLD) functional activity as well as behavioral performance during working memory was examined in a subsample of 9 patients and 18 controls. Compared with controls, schizophrenia patients showed reduced total connectivity of the thalamus to only one of six cortical regions, the LPFC. The size of the thalamic region with at least 25% of model fibers reaching the LPFC was also reduced in patients compared with controls. The total thalamocortical connectivity to the LPFC predicted working memory task performance and also correlated with LPFC BOLD activation. Notably, the correlation with BOLD activation was accentuated in patients as compared with controls in the ventral LPFC. These results suggest that thalamocortical connectivity to the LPFC is altered in schizophrenia with functional consequences on working memory processing in LPFC.

GH does not modulate the early fasting-induced release of free fatty acids in mice

Fasting results in the mobilization of adipose stores and the elevation of levels of free fatty acids (FFA). In humans, this process is driven by a release in GH. Little is known regarding the role of GH in modulating this process during early stages of fasting in the mouse. Confirmation of the role of GH in modulating FFA release in the fasting mouse is of particular importance given the frequent use of mouse models to study metabolic mechanisms. Here, we correlate the initial release of FFA throughout fasting in mice with pulsatile GH secretion. Observations illustrate the rapid release of FFA in response to food withdrawal. This does not correlate with a rise in GH secretion. Rather, we observed a striking loss in pulsatile secretion of GH throughout the first 6 h of fasting, suggesting that GH does not modulate the initial release of FFA in the mouse in response to fasting. This was confirmed in GH receptor knockout mice, in which we observed a robust fasting-induced rise in FFA. We further illustrate the dynamic relationship between the orexigenic and anorexigenic hormones ghrelin and leptin during fasting in the mouse. Our findings show an initial suppression of leptin and the eventual rise in circulating levels of acyl-ghrelin with fasting. However, altered acyl-ghrelin and leptin secretion occurs well after the rise in FFA and the suppression of GH secretion. Consequently, we conclude that although acyl-ghrelin and leptin may modulate the physiological response to drive food intake, these changes do not contribute to the initial loss of pulsatile GH secretion. Rather, it appears that the suppression of GH secretion in fasting may occur in response to an elevation in fasting levels of FFA or physiological stress. Observations highlight a divergent role for GH in modulating FFA release between man and mouse.

Development of a method for the determination of pulsatile growth hormone secretion in mice

Measures of pulsatile GH secretion require frequent collection and analysis of blood samples at regular intervals. Due to blood volume constraints, repeat measures of circulating levels of GH in mice remain challenging. Consequently, few observations exist in which the pulsatile pattern of GH secretion in mice have been characterized. To address this, we developed a technique for the collection and analysis of circulating levels of GH at regular and frequent intervals in freely moving mice. This was achieved through the development of a sensitive assay for the detection of GH in small (2 μl) quantities of whole blood. The specificity and accuracy of this assay was validated following guidelines established for single-laboratory validation as specified by the International Union of Pure and Applied Chemistry. We incorporated an established method for tail-clip blood sample collection to determine circulating levels of GH secretion in 36 whole blood samples collected consecutively over a period of 6 h. Resulting measures were characterized by peak secretion periods and interpulse stable baseline secretion periods. Periods characterized by elevated whole blood GH levels consisted of multicomponent peaks. Deconvolution analysis of resulting measures confirmed key parameters associated with pulsatile GH secretion. We show a striking decrease in pulsatile GH secretion in mice after 12-18 h of fasting. This model is necessary to characterize the pulsatile profile of GH secretion in mice and will significantly contribute to current attempts to clarify mechanisms that contribute to the regulation of GH secretion.

Interactive effects of DAOA (G72) and catechol-O-methyltransferase on neurophysiology in prefrontal cortex

BACKGROUND

Accumulating evidence indicates that genetic polymorphisms of D-amino acid oxidase activator (DAOA) (M24; rs1421292; T-allele) and catechol-O-methyltransferase (COMT) (Val¹⁵⁸Met; rs4680) likely enhance susceptibility to schizophrenia. Previously, clinical association between DAOA M24 (T-allele) and a functionally inefficient 3-marker COMT haplotype (that included COMT Val¹⁵⁸Met) uncovered epistatic effects on risk for schizophrenia. Therefore, we projected that healthy control subjects with risk genotypes for both DAOA M24 (T/T) and COMT Val¹⁵⁸Met (Val/Val) would produce prefrontal inefficiency, a critical physiological marker of the dorsolateral prefrontal cortex (DLPFC) in schizophrenic patients influenced by both familial and heritable factors.

METHODS

With 3T blood oxygen level dependent functional magnetic resonance imaging data, we analyzed in SPM5 the proposed interaction of DAOA and COMT in 82 healthy volunteers performing an N-back executive working memory paradigm (2-back > 0-back).

RESULTS

As predicted, we detected a functional gene x gene interaction between DAOA and COMT in the DLPFC.

CONCLUSIONS

The neuroimaging findings here of inefficient information processing in the prefrontal cortex seem to echo prior statistical epistasis between risk alleles for DAOA and COMT, albeit within a small sample. These in vivo results suggest that deleterious genotypes for DAOA and COMT might contribute to the pathophysiology of schizophrenia, perhaps through combined glutamatergic and dopaminergic dysregulation.

Cloning, expression and protective capacity of 37 kDa outer membrane protein gene (ompH) of Pasteurella multocida serotype B:2

The major outer membrane protein (OmpH) of 4 local Malaysian strains of Pasteurella multocida serotype B:2 were characterized in comparison to ATCC strains. Three major peptide bands of MW 26, 32 and 37 kDa were characterized using SDSPAGE. Two of these fragments, the 32 kDa and 37 kDa were observed to be more reactive with a mouse polyclonal antiserum in all of the local isolates as well as the ATCC strains in a Western blot. However, the 32 kDa fragment was found to cross react with other Gram negative bacteria. Therefore, the 37 kDa OmpH was selected as vaccine candidate. The 37 kDa ompH gene of the isolated strain 1710 was cloned into an Escherichia coli expression vector to produce large amounts of recombinant OmpH (rOmpH). The 37 kDa ompH gene of strain 1710 was sequenced. In comparison to a reference strain X-73 of the ompH of P. multocida, 39bp was found deleted in the 37 kDa ompH gene. However, the deletion did not shift the reading frame or change the amino acid sequence. The rOmpH was used in a mice protection study. Mice immunized and challenged intraperitoneally resulted 100% protection against P. multocida whilst mice immunized subcutaneously and challenged intraperitoneally only resulted 80% protection. The rOmpH is therefore a suitable candidate for vaccination field studies. The same rOmpH was also used to develop a potential diagnostic kit in an ELISA format.

Biological validation of increased schizophrenia risk with NRG1, ERBB4, and AKT1 epistasis via functional neuroimaging in healthy controls

CONTEXT

NRG1 is a schizophrenia candidate gene and plays an important role in brain development and neural function. Schizophrenia is a complex disorder, with etiology likely due to epistasis.

OBJECTIVE

To examine epistasis between NRG1 and selected N-methyl-d-aspartate-glutamate pathway partners implicated in its effects, including ERBB4, AKT1, DLG4, NOS1, and NOS1AP.

DESIGN

Schizophrenia case-control sample analyzed using machine learning algorithms and logistic regression with follow-up using neuroimaging on an independent sample of healthy controls.

PARTICIPANTS

A referred sample of schizophrenic patients (n = 296) meeting DSM-IV criteria for schizophrenia spectrum disorder and a volunteer sample of controls for case-control comparison (n = 365) and a separate volunteer sample of controls for neuroimaging (n = 172).

MAIN OUTCOME MEASURES

Epistatic association between single-nucleotide polymorphisms (SNPs) and case-control status; epistatic association between SNPs and the blood oxygen level-dependent physiological response during working memory measured by functional magnetic resonance imaging.

RESULTS

We observed interaction between NRG1 5' and 3' SNPs rs4560751 and rs3802160 (likelihood ratio test P = .00020) and schizophrenia, which was validated using functional magnetic resonance imaging of working memory in healthy controls; carriers of risk-associated genotypes showed inefficient processing in the dorsolateral prefrontal cortex (P = .015, familywise error corrected). We observed epistasis between NRG1 (rs10503929; Thr286/289/294Met) and its receptor ERBB4 (rs1026882; likelihood ratio test P = .035); a 3-way interaction with these 2 SNPs and AKT1 (rs2494734) was also observed (odds ratio, 27.13; 95% confidence interval, 3.30-223.03; likelihood ratio test P = .042). These same 2- and 3-way interactions were further biologically validated via functional magnetic resonance imaging: healthy individuals carrying risk genotypes for NRG1 and ERBB4, or these 2 together with AKT1, were disproportionately less efficient in dorsolateral prefrontal cortex processing. Lower-level interactions were not observed between NRG1 /ERBB4 and AKT1 in association or neuroimaging, consistent with biological evidence that NRG1 × ERBB4 interaction modulates downstream AKT1 signaling.

CONCLUSION

Our data suggest complex epistatic effects implicating an NRG1 molecular pathway in cognitive brain function and the pathogenesis of schizophrenia.

Use of propranolol in infantile haemangioma among Chinese children

OBJECTIVE

To describe the use of propranolol as first-line treatment or as single therapy to control the proliferating phase of infantile haemangioma in Chinese children.

DESIGN

Retrospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Children 3 years old or younger with facial haemangioma who took oral propranolol between 1 December 2008 and 1 December 2009.

RESULTS

There were 12 such patients, all of whom underwent prior clinical evaluation before starting the treatment. Ten patients had a solitary facial haemangioma and two had multiple haemangiomas. The mean age of symptom onset was 12 days. The mean age for starting propranolol treatment was 7 months, and in all cases a clinical response was observed within 7 days. Five (41%) of the patients had complete resolution 2 to 6 months after starting medication, at which time they were 5 to 12 months old. Two of them had a recurrence of the haemangioma within 8 weeks of stopping the drug, but responded to a second treatment course. In these two patients, the propranolol dosage had been tailed down rapidly and the therapy was of a shorter duration than in those without recurrence. The remaining seven patients are still taking propranolol and responding satisfactorily. Hypotension was observed in two patients, one of whom tolerated a lower dose and in the other, therapy was reinitiated at her older age. No serious side-effect was encountered in the remaining patients.

CONCLUSION

Propranolol was useful as first-line or single-agent treatment of facial infantile haemangioma in Chinese children, and gave rise to minimal side-effects. Although recurrence of infantile haemangioma occurred after propranolol was tailed off rapidly after a relatively short duration, an optimal treatment duration and tapering schedule has not yet been defined. Nevertheless, patients responded well to second courses of propranolol therapy.

Observation of dynamic samples using simple coverslip fluidics

The ability to observe samples undergoing controlled fluid flow under the microscope is important for studying biochemical processes and motion dynamics. We describe here a simple method to achieve this using coverslips shaped using a fiber scribe. Testing showed good directional flow control within the test range of 0-1 ml/min flow rate and an ability to sustain a flow rate up to approximately 1 ml/min. Testing with a sealed T-channel coverslip demonstrated the ability to construct fluid network branches with this scheme. We also demonstrated the usefulness of this procedure in motion dynamic studies of Dunaliella algae swimming under fluid flow.

Age-related alterations in simple declarative memory and the effect of negative stimulus valence

Healthy aging has been shown to modulate the neural circuitry underlying simple declarative memory; however, the functional impact of negative stimulus valence on these changes has not been fully investigated. Using BOLD fMRI, we explored the effects of aging on behavioral performance, neural activity, and functional coupling during the encoding and retrieval of novel aversive and neutral scenes. Behaviorally, there was a main effect of valence with better recognition performance for aversive greater than neutral stimuli in both age groups. There was also a main effect of age with better recognition performance in younger participants compared to older participants. At the imaging level, there was a main effect of valence with increased activity in the medial-temporal lobe (amygdala and hippocampus) during both encoding and retrieval of aversive relative to neutral stimuli. There was also a main effect of age with older participants showing decreased engagement of medial-temporal lobe structures and increased engagement of prefrontal structures during both encoding and retrieval sessions. Interestingly, older participants presented with relatively decreased amygdalar-hippocampal coupling and increased amygdalar-prefrontal coupling when compared to younger participants. Furthermore, older participants showed increased activation in prefrontal cortices and decreased activation in the amygdala when contrasting the retrieval of aversive and neutral scenes. These results suggest that although normal aging is associated with a decline in declarative memory with alterations in the neural activity and connectivity of brain regions underlying simple declarative memory, memory for aversive stimuli is relatively better preserved than for neutral stimuli, possibly through greater compensatory prefrontal cortical activity.

Prefrontal cognitive systems in schizophrenia: towards human genetic brain mechanisms

Schizophrenia has complex genetic heritability. It is also genetically heterogeneous. To the extent that genes are associated with symptom constellations in schizophrenia, they do so by affecting the development and function of neural systems that mediate the expression of such diverse behavioral, cognitive and perceptual phenomena. The genetic mechanisms of human brain dysfunction remain to be well understood. "Imaging genetics" is an emerging field that attempts to integrate the basic biology of putative disease mechanisms with physiological correlates from the live human brain. Here, we review recent imaging genetics work on prefrontal brain systems associated with working memory and executive function - heritable traits relevant to schizophrenia. Starting with genetic variation in dopaminergic systems (e.g., COMT), we examined the modulation of prefrontal brain networks during active cognitive processing; there is also evidence that variation in the expression of dopamine-related downstream intra-cellular signaling molecules (e.g., AKT1) are implicated. Moreover, these genetic variants evidence epistasis on neuroimaging measures, lending further support to the conceptualization that non-additive combinations of multiple genes modulate active human cognitive brain mechanisms. The imaging genetics platform therefore could extend understanding of genetic mechanisms of human cognitive brain processes relevant to neuropsychiatric disease.

Immunological profiles of immune restoration disease presenting as mycobacterial lymphadenitis and cryptococcal meningitis

OBJECTIVES

A proportion of HIV patients beginning antiretroviral therapy (ART) develop immune restoration disease (IRD). Immunological characteristics of IRD were investigated in a cohort of HIV patients beginning therapy in Kuala Lumpur, Malaysia.

METHODS

Peripheral blood mononuclear cells were collected at weeks 0, 6, 12, 24 and 48 of ART from five patients experiencing IRD [two with cryptococcal and three with Mycobacterium tuberculosis (Mtb) disease], eight non-IRD controls who had begun ART with CD4 T-cell counts of <100 cells/microL and 17 healthy controls. Leukocytes producing interferon-gamma (IFNgamma) were quantified by enzyme-linked immunospot assay after stimulation with purified protein derivative (PPD), early secretory antigenic target-6 (ESAT-6), Cryptococcus neoformans or Cytomegalovirus antigens. Plasma immunoglobulin (IgG) antibodies reactive with these antigens were assessed by enzyme-linked immunosorbent assay. Proportions of activated (HLA-DR(hi)) and regulatory (CD25 CD127(lo) and CTLA-4(+)) CD4 T-cells were quantified by flow cytometry.

RESULTS

Plasma HIV RNA declined and CD4 T-cell counts rose within 8-27 weeks on ART. Mtb IRD patients displayed elevated IFNgamma responses and/or plasma IgG to PPD, but none responded to ESAT-6. Cryptococcal IRD occurred in patients with low baseline CD4 T-cell counts and involved clear IFNgamma and antibody responses to cryptococcal antigen. Proportions of activated and regulatory CD4 T-cells declined on ART, but remained higher in patients than in healthy controls. At the time of IRD, proportions of activated CD4 T-cells and regulatory CD4 T-cells were generally elevated relative to other patients.

CONCLUSIONS

Cryptococcal and Mtb IRD generally coincide with peaks in the proportion of activated T-cells, pathogen-specific IFNgamma responses and reactive plasma IgG. IRD does not reflect a paucity of regulatory CD4 T-cells.

Age-related alterations in default mode network: impact on working memory performance

The default mode network (DMN) is a set of functionally connected brain regions which shows deactivation (task-induced deactivation, TID) during a cognitive task. Evidence shows an age-related decline in task-load-related modulation of the activity within the DMN during cognitive tasks. However, the effect of age on the functional coupling within the DMN and their relation to cognitive performance has hitherto been unexplored. Using functional magnetic resonance imaging, we investigated functional connectivity within the DMN in older and younger subjects during a working memory task with increasing task load. Older adults showed decreased connectivity and ability to suppress low frequency oscillations of the DMN. Additionally, the strength of the functional coupling of posterior cingulate (pCC) with medial prefrontal cortex (PFC) correlated positively with performance and was lower in older adults. pCC was also negatively coupled with task-related regions, namely the dorsolateral PFC and cingulate regions. Our results show that in addition to changes in canonical task-related brain regions, normal aging is also associated with alterations in the activity and connectivity of brain regions within the DMN. These changes may be a reflection of a deficit in cognitive control associated with advancing age that results in deficient resource allocation to the task at hand.

Genetic variation in AKT1 is linked to dopamine-associated prefrontal cortical structure and function in humans

AKT1-dependent molecular pathways control diverse aspects of cellular development and adaptation, including interactions with neuronal dopaminergic signaling. If AKT1 has an impact on dopaminergic signaling, then genetic variation in AKT1 would be associated with brain phenotypes related to cortical dopaminergic function. Here, we provide evidence that a coding variation in AKT1 that affects protein expression in human B lymphoblasts influenced several brain measures related to dopaminergic function. Cognitive performance linked to frontostriatal circuitry, prefrontal physiology during executive function, and frontostriatal gray-matter volume on MRI were altered in subjects with the AKT1 variation. Moreover, on neuroimaging measures with a main effect of the AKT1 genotype, there was significant epistasis with a functional polymorphism (Val158Met) in catechol-O-methyltransferase [COMT], a gene that indexes cortical synaptic dopamine. This genetic interaction was consistent with the putative role of AKT1 in dopaminergic signaling. Supportive of an earlier tentative association of AKT1 with schizophrenia, we also found that this AKT1 variant was associated with risk for schizophrenia. These data implicate AKT1 in modulating human prefrontal-striatal structure and function and suggest that the mechanism of this effect may be coupled to dopaminergic signaling and relevant to the expression of psychosis.

Dysfunctional and compensatory prefrontal cortical systems, genes and the pathogenesis of schizophrenia

Cognitive deficits are critical determinants of schizophrenia morbidity. In this review, we offer a mechanistic perspective regarding schizophrenia-related changes observed in prefrontal cortical networks engaged in working memory. A body of earlier work converges on aberrations in putative macrocircuit stability and functional efficiency as the underlying pathophysiology of the cognitive deficits in schizophrenia. In parsing the dysfunctional prefrontal cortical dynamics of schizophrenia, recent functional magnetic resonance imaging and electoencephalography works suggest that in the context of reduced capacity for executive aspects of working memory, patients engage a larger network of cortical regions consistent with an interplay between reduced signal-to-noise components and the recruitment of compensatory networks. The genetic programming underlying these systems-level cortical interactions has been examined under the lens of certain schizophrenia susceptibility genes, especially catechol-o-methyltransferase (COMT) and GRM3. Variation in COMT, which presumably impacts on cortical dopamine signaling, translates into variable neural strategies for working memory and altering patterns of intracortical functional correlations. GRM3, which impacts on synaptic glutamate, interacts with COMT and exaggerates the genetic dissection of cortical processing strategies. These findings reveal novel insights into the modulation and parcellation of working memory processing in cortical assemblies and provide a mechanistic link between susceptibility genes and cortical pathophysiology related to schizophrenia.

Epistasis between catechol-O-methyltransferase and type II metabotropic glutamate receptor 3 genes on working memory brain function

Dopaminergic and glutamatergic systems are critical components responsible for prefrontal signal-to-noise tuning in working memory. Recent functional MRI (fMRI) studies of genetic variation in these systems in catechol-O-methyltransferase (COMT) and in metabotropic glutamate receptor mgluR3 (GRM3), respectively, suggest that these genes influence prefrontal physiological signal-to-noise in humans. Here, using fMRI, we extend these individual gene findings to examine the combined effects of COMT and GRM3 on dissociable components of the frontoparietal working memory network. We observed an apparent epistatic interaction of these two genes on the engagement of prefrontal cortex during working memory. Specifically, the GRM3 genotype putatively associated with suboptimal glutamatergic signaling was significantly associated with inefficient prefrontal engagement and altered prefrontal-parietal coupling on the background of COMT Val-homozygous genotype. Conversely, COMT Met-homozygous background mediated against the effect of GRM3 genotype. These findings extend putative brain dopaminergic and glutamatergic relationships indexed by COMT and GRM3 to a systems-level interaction in human cortical circuits implicated in working memory dysfunction such as in schizophrenia.

Dysfunctional prefrontal regional specialization and compensation in schizophrenia

OBJECTIVE

It has been suggested that in healthy persons higher-order cognitive processing engaged by incremental working memory load hierarchically employs more dorsal than ventral prefrontal resources in healthy individuals. Given that working memory performance is impaired in schizophrenia, especially at higher executive loads, the authors investigated how this prefrontal functional organization might be altered in disease, independent of performance deficits.

METHOD

Using N-back working memory functional magnetic resonance imaging (fMRI) data, the authors studied 15 patients with schizophrenia and 26 healthy comparison subjects. Subgroups based on median performance accuracy at 2-back were analyzed; high performers included eight schizophrenia patients and 14 comparison subjects, and low performers included seven patients and 12 comparison subjects.

RESULTS

High-performing but not low-performing comparison subjects responded to incremental working memory executive load with disproportionately greater dorsal but not ventral prefrontal cortex activation, which also predicted performance accuracy. In the high- and low-performing patient groups, incremental working memory load caused a disproportionate increase in ventral but not dorsal prefrontal cortex activation relative to the respective comparison group, which also correlated with accuracy. Functional connectivity between the ventral prefrontal cortex and posterior parietal cortex was relatively greater in patients, whereas comparison subjects had greater functional connectivity between the dorsal prefrontal cortex and posterior parietal cortex.

CONCLUSIONS

The hierarchical organization of the prefrontal cortex may be compromised in schizophrenia, resulting in loss of functional specialization and integration at the dorsal prefrontal cortex and in compensatory activation from the ventral prefrontal cortex, which may ultimately affect working memory and executive cognition.

fMRI study of maintenance and manipulation processes within working memory in first-episode schizophrenia

OBJECTIVE

Working memory, a critical cognitive capacity that is affected in schizophrenia, can be divided into maintenance and manipulation processes. Previous behavioral research suggested that manipulation is more affected than maintenance in patients with chronic schizophrenia. In this study of first-episode schizophrenia patients, the authors evaluated the extent to which the two working memory processes are affected early in the course of schizophrenia.

METHOD

Study subjects were 11 first-episode schizophrenia patients and 11 matched healthy comparison subjects. Each group performed two verbal working memory tasks while undergoing functional magnetic resonance imaging. One task required maintenance of information; the other required manipulation of information in addition to maintenance.

RESULTS

Under behaviorally matched conditions, both groups activated a predominantly left-sided frontal-parietal network. The manipulation plus maintenance task elicited activation of greater magnitude and spatial extent. With both tasks, patients showed less bilateral dorsolateral prefrontal cortex activation and greater ventrolateral prefrontal cortex activation, relative to the comparison subjects. A group-by-task interaction was observed for activation at the left dorsolateral and ventrolateral prefrontal cortex. The increase in activation when patients engaged in the manipulation plus maintenance task was disproportionately less in the dorsolateral prefrontal cortex and greater in the ventrolateral prefrontal cortex.

CONCLUSIONS

These functional neuroanatomical findings add support to earlier suggestions that manipulation of information is selectively more affected than maintenance of information in persons with schizophrenia. They also suggest the presence of interacting regions of dysfunctional and compensatory prefrontal responses in the dorsolateral and ventrolateral prefrontal cortex, respectively, that are more prominent when information is manipulated. This disrupted prefrontal network is present relatively early in the course of schizophrenia.