Neonatal mortality among preterm infants admitted to neonatal intensive care units in India and Pakistan: A prospective study

OBJECTIVE

To explore potential reasons for differences in preterm neonatal mortality in neonatal intensive care units (NICUs) in India and Pakistan.

DESIGN

A prospective observational study, the Project to Understand and Research Stillbirth and Preterms in Southeast Asia (PURPOSe) was conducted July 2018 to February 2020.

SETTING

Three hospitals in Davangere, India, and a large public hospital in Karachi, Pakistan.

POPULATION

Of a total of 3,202 preterm infants enrolled, 1,512 were admitted to a study NICU.

METHODS

We collected data for neonates, including length of stay, diagnoses, and diagnostic tests.

MAIN OUTCOME MEASURES

Neonatal mortality, tests performed, diagnoses ascertained.

RESULTS

For infants of equivalent weights and gestational ages, neonatal mortality in Pakistan was twice that in the Indian NICU. The mean newborn length of stay in Pakistan was 2 days compared with 10 days for India. Fewer diagnostics and other investigations were used to determine neonatal condition or guide treatment in the Pakistani NICU. Because of limited information from testing in Pakistan concerning clinical respiratory distress, respiratory distress syndrome appeared to be over-diagnosed, whereas other conditions including pneumonia, sepsis, necrotising entercolitis and intraventricular haemorrhage were rarely diagnosed.

CONCLUSION

In the Pakistani site, the limited resources available to the NICU appeared related to a shorter length of stay and decreased diagnostic testing, likely explaining the higher mortality. With improved care, reduction in mortality among preterm neonates should be achievable.

KatG catalase deficiency confers bedaquiline hyper-susceptibility to isoniazid resistant Mycobacterium tuberculosis

Multidrug-resistant tuberculosis (MDR-TB) is a growing source of global mortality and threatens global control of tuberculosis (TB) disease. The diarylquinoline bedaquiline (BDQ) recently emerged as a highly efficacious drug against MDR-TB, defined as resistance to the first-line drugs isoniazid (INH) and rifampin. INH resistance is primarily caused by loss-of-function mutations in the catalase KatG, but mechanisms underlying BDQ's efficacy against MDR-TB remain unknown. Here we employ a systems biology approach to investigate BDQ hyper-susceptibility in INH-resistant Mycobacterium tuberculosis . We found hyper-susceptibility to BDQ in INH-resistant cells is due to several physiological changes induced by KatG deficiency, including increased susceptibility to reactive oxygen species and DNA damage, remodeling of transcriptional programs, and metabolic repression of folate biosynthesis. We demonstrate BDQ hyper-susceptibility is common in INH-resistant clinical isolates. Collectively, these results highlight how altered bacterial physiology can impact drug efficacy in drug-resistant bacteria.

Clinical profile of children with posterior urethral valve at Tertiary Care Center

Background & Objective: Posterior Urethral Valves (PUV) are common cause of congenital obstructive uropathy in boys and may be associated with urinary tract infection(UTI) and chronic kidney disease(CKD) if not managed timely. The objective of our study was to determine the clinical profile of children with PUV. Methods: This is a descriptive case series comprising of 30 children aged 1-5 years, diagnosed and managed as PUV over six months, conducted at the Department of Pediatric Nephrology, National Institute of Child Health, Karachi. Patients were followed for 12 weeks and the outcome was assessed in terms of recovery, UTI, urinary incontinence and CKD. Descriptive statics were used for data analysis. Results: Thirty cases of PUV were managed during study period. Clinical presentations were poor urinary stream (83%), fever (73%), signs and symptom suggesting UTI (96.6%), pallor (73.3%), acute kidney injury (37%)and urinary retention (13%). UTI was confirmed in 73.3 % and E.Coli was the most common pathogen. Ultrasonography showed bilateral hydronephrosis/hydroureter in 80% and micturating cystourethrogram demonstrated vesicoureteral reflux in 86.66% cases. All patients received intravenous hydration (97%), urinary decompression, and antibiotics. Meropenem was the most commonly used. Packed cell transfusion and peritoneal dialysis was done in 73.33% and 13.3% respectively. Cystoscopic valve fulguration was done in 86.66% and vesicostomy in 13.3%. On short-term follow-up, 60% recovered,16.66% experienced UTI and remained incontinent whereas 23.33% had CKD. Conclusion: Our study showed a high frequency of UTI and AKI. E. coli was most common pathogen. Despite valve fulgration, significant patients had CKD. doi: https://doi.org/10.12669/pjms.38.7.5823 How to cite this:Yamin R, Moorani K, Shaikh M, Yamin S. Clinical profile of children with posterior urethral valve at Tertiary Care Center. Pak J Med Sci. 2022;38(7):1821-1826. doi: https://doi.org/10.12669/pjms.38.7.5823 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

199 An Audit Cycle of Antibiotic Prophylaxis for Laparoscopic Cholecystectomy

Aim

Due to the lack of clinical benefit and the risks of unnecessary antimicrobial use, current national guidelines do not recommend prophylactic antibiotic use in low-risk elective laparoscopic cholecystectomies, reserving their use for high-risk patients only. The aim of this audit was to assess compliance with local and national guidelines for antibiotic usage for laparoscopic cholecystectomies, to identify areas of improvement, implement change and re-audit to assess the effectiveness of this change.

Method

Data was collected retrospectively between 01/05/2021 and 01/08/2021 for patients undergoing elective laparoscopic cholecystectomies. Following the initial data collection, we implemented change by attaching pre-printed stickers of local antibiotic prophylaxis guidance to pre-operative notes. We prospectively re-audited between 01/11/21 and 01/12/21 to assess the effectiveness of this change.

Results

In the initial three-month period, 24.4% (10/41) of elective cases received correct antibiotic prophylaxis, with 58.5% of patients prescribed unnecessary post-operative antibiotics in the post-operative plan. Following the implementation of change, in the re-audit period there was a significant improvement, with 55% (11/20) of elective cases receiving correct antibiotic prophylaxis, and only 25% prescribed unnecessary post-operative antibiotics.

Conclusions

We show that pre-printed stickers are a simple intervention that can improve adherence to local guidance and reduce injudicious use of antibiotics in the pre- and post-operative periods. Improving antibiotic prescribing for laparoscopic cholecystectomies, one of the United Kingdom's most common surgical procedures, highlights the potential for significant cost savings and improved antimicrobial stewardship. We will re-audit again in the coming months to assess if this improvement has been sustained.

Pattern and Outcome of Dengue Fever in a Pediatric Tertiary Hospital: A Retrospective Report

Introduction

For Pakistan, dengue has been established as a public health problem. With superimposed factors such as poor socioeconomic conditions, limited public health awareness, poor hygiene, and sanitation conditions, the situation has become more severe and complications have become frequent. Almost 90% of all infections occur in children of age less than 18 years. This is a three-year retrospective report of dengue fever in Southern Pakistan.

Methods

In this retrospective analysis, all records of patients admitted to the National Institute of Child Health, Karachi, from May 1, 2016, till April 30, 2019, diagnosed with dengue fever were recruited. Their demographic, clinical, and biochemical records were assessed. The outcome was also recorded. Data were entered and analyzed using Statistical Package for Social Sciences (SPSS) for Windows version 20.0 (IBM Corp., Chicago).

Results

Among 93 cases of dengue fever, there were 71 (76.3%) male and 22 (23.7%) female children. Their mean age was 5.7 ± 3.07 years. The mean duration from onset of disease to hospitalization was 4.2 ± 2.1 days. The mean platelet count was 47391.30 ± 41370.61 x 10⁹/L. Fever (100%) and abdominal pain (35.5%) were common presentations. Bleeding episodes were seen in 31% of children, rash in 15%, disseminated intravascular coagulation in 3%, and 1% developed pleural effusion. There were no mortalities; 87 (93.5%) were discharged and six (6.5%) children left against medical advice.

Conclusion

Fever, abdominal pain, bleeding episodes, and rash were common presentations. Hematological, hepatological, neurological, and pleural complications were not uncommon. The outcome of the disease was adequate and there were no mortalities.

Integrating a Sport-Based Trauma-Sensitive Program in a National Youth-Serving Organization

There is a pressing need to equip youth-serving community organizations to respond to the unique needs of trauma-exposed children. Early prevention measures can be an effective means of redirecting children to self-regulatory healing, while facilitating their transition toward strength-based thriving. Sport can offer a powerful opportunity to reach these children; however there remains little information on how to effectively develop, deliver, evaluate, and sustain trauma-sensitive sport programs in a community context. The purpose of this paper is to outline a case study of integrating sport-based trauma-sensitive practices with BGC Canada's national Bounce Back League program. An interdisciplinary partnership of academic, community, and practice experts used a community-based participatory action research approach, paired with a knowledge translational approach, to guide the process of program development. Mixed methods (e.g., surveys, logbooks, interviews, focus groups, online communications) were used to generate ongoing insights of staff's training experiences, successes and challenges of program implementation, and potential impact of program on club members. Several stages of program development are described, including: (a) collaboratively planning the program; (b) piloting the program to three clubs; (c) adapting the program using pilot insights; (d) expanding the adapted program to ten clubs; and (e) creating opportunities to maintain, sustain, and scale-out practices throughout grant duration and beyond. Lessons learned regarding the leadership team's experiences in terms of developing, adapting, and integrating trauma-sensitive practices in this community context are shared.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10560-021-00776-7.

Spectrum and Antimicrobial Susceptibility Pattern of Micro-Organisms Associated With Neonatal Sepsis in a Hospital in Karachi, Pakistan

Background Neonatal sepsis is one of the most common causes of neonatal mortality and morbidity, particularly in developing countries. Its causative bacteria and their respective sensitivity patterns are different in each hospital and region. The objective of this study was to determine the causative bacteria and their antibiotics sensitivity patterns at the neonatal unit. Methods This prospective study was carried out at the Neonatology Unit of Kharadar General Hospital (KGH) from January 2017 to Jun 2019. A total of 162 neonates with suspected sepsis and positive blood cultures were included in the study. Blood culture was done by standard microbiological techniques (BACTEC Method). Continuous data were presented as mean and standard deviation, while categorical data were presented in frequency and percentages. Result Out of a total of 162 neonates with blood culture positive neonatal sepsis, males were 106 (65.4%). Gram-positive and Gram-negative bacteria were found with a frequency of 83 (51.5%) and 79 (48.5%), respectively. Staphylococcus aureus and Pseudomonas were the commonest isolates in 50.5% and 25.7% of cases, respectively. The Gram-positive organism was mostly sensitive to amikacin and vancomycin whereas the Gram-negative was mostly sensitive to amikacin, imipenem, meropenem, and ciprofloxacin. Conclusion Staphylococcus aureus was the most common bacteria isolated. For the sepsis, the causative bacteria and antibiotics sensitivity pattern changes over a period of time. Continued surveillance is required to help reduce morbidity and mortality through developing institution-based guidelines.

Frequency of Various Foreign Bodies Retrieved from the Airway During Bronchoscopy in Children: A Pediatric Tertiary Care Center Experience

Objective: To determine the frequency of various foreign bodies (FBs) retrieved from the airway during bronchoscopy in children at the National Institute of Child Health (NICH), Karachi, Pakistan.

Study Design: Cross-sectional descriptive study.

Place and Duration: Department of Pediatrics Surgery, NICH, Karachi, Pakistan from June 1, 2017 to November 30, 2017.

Methodology: Patients referred from the ER and Pediatrics Medicine Department, NICH, Karachi with a suspicion of tracheobronchial foreign body aspiration (FBA) was included in the study.

Results: A total of 96 children were studied. There were 71 males (74%) and 25 females (26%). Eighty-seven (90.6%) were below five years and nine (9.4%) were more than five years of age. Mean time interval between FBA and presentation at hospital was 15 h. FB was located primarily in the right main bronchus (54%), followed by left bronchus (40%) and trachea (6%). Betel nut was the most common FB retrieved in 87.5%. Other FBs were whistle 3.1%, peanut 3.1%, seed 1%, and miscellaneous 5.2%.

Conclusions: FBA is more common in male children, mostly below five years of age. During bronchoscopy, it was found that the FB was mostly located in the right main bronchus. Betel nut was found to be the most common FB aspirated.

AB0356 TARGETING THE RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLAST VIA CYCLIN DEPENDENT KINASE INHIBITION (TRAFIC): A PHASE 1B STUDY TO DETERMINE THE MAXIMUM TOLERATED DOSE OF SELICICLIB FOR REPURPOSING IN RHEUMATOID ARTHRITIS

Background:

Current rheumatoid arthritis (RA) therapeutics target immune inflammation and are subject to ceiling effects, with non-response observed in a third of recipients together with low remission rates. Synovial fibroblasts (SFs) are stromal cells not yet targeted in RA, whose hyperplastic and proliferative properties drive inflammation and tissue destruction. Seliciclib (R-roscovitine) is an orally available cyclin-dependent kinase (CDK) inhibitor that suppresses SF proliferation and ameliorates inflammatory arthritis in rodents.

Objectives:

To determine the maximum tolerated dose (MTD) of seliciclib in patients with active RA despite anti-TNF, with or without background conventional disease modifying anti-rheumatic drugs (cDMARDs). Safety and pharmacokinetics (PK) were also evaluated.

Methods:

A restricted, one-stage Bayesian continual reassessment method (CRM) determined MTD based on a target dose-limiting toxicity (DLT) probability of 35%. RA patients (DAS28 ≥3.2) were recruited sequentially to cohorts of 3 subjects each. Cohort 1 received 400mg seliciclib daily for 4 consecutive days each week for 4 weeks, added to existing therapy. Each subsequent cohort received a dose determined by the toxicity-based CRM algorithm, calculated upon conclusion of the previous cohort. Safety was assessed through adverse event (AE) monitoring. Associations with relevant PK parameters were sought.

Results:

15 anti-TNF recipients were enrolled, 10 of whom were also taking cDMARDs (median DAS28 4.9). Application of the CRM algorithm prompted one dose increment during the study (to 600mg for cohort 2), but reversion to 400mg for subsequent cohorts (Figure 1A). After treatment of 5 cohorts, 400mg was determined the MTD, with a DLT probability of 0.35 (CI 0.18-0.52; Figure 1B). 6 patients experienced DLTs, of which two were classified as serious AEs (SAEs) in keeping with the safety profile of seliciclib; these are summarised in Table 1. Of 43/65 total AEs reported at any dose that didnotcontribute to a DLT, 26 were possibly, probably or definitely related to seliciclib; 19 of these 26 were mild, 7 moderate and none severe. The most frequent AE was mild nausea. No relationship of safety and/or tolerability with concomitant cDMARD use or PK was seen.

Table 1.

Characteristics of patients who developed HZ at initiation of baricitinib

DLTSeliciclib dose (mg)Doses receivedContributing AEsContributing SAEsDescriptionOutcomeA1400830Constipation, N+V, liver injury; fatigue.Resolved2600430Constipation, N+V.Resolved3600101BFever, N+V, renal injury.Resolved4400831BConstipation, N+V, jaundice, liver injury.Resolved5400840Fever, dizziness, liver injury.Resolved6400890Dizziness, N+V, liver injury, bilirubin rise.Persistent AST rise

Conclusion:

The MTD of seliciclib has been defined for RA. No unexpected safety concerns were identified to preclude ongoing evaluation in patients, which focuses on clinical, radiological and biological indicators of efficacy.

Disclosure of Interests:

Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein, Stefan Siebert Grant/research support from: BMS, Boehringer Ingelheim, Celgene, GlaxoSmithKline, Janssen, Novartis, Pfizer, UCB, Consultant of: AbbVie, Boehringer Ingelheim, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Celgene, Janssen, Novartis, Michael Cole: None declared, Deborah Stocken: None declared, Stephen Kelly: None declared, Muddassir Shaikh: None declared, Amy Cranston: None declared, Miranda Morton: None declared, Jennifer Walker: None declared, Sheelagh Frame Employee of: Cyclacel Ltd., Wan-fai Ng: None declared, Chris Buckley Consultant of: Janssen, Pfizer, GSK, Galapagos, Gillead, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Andrew Filer: None declared, John D Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche

Malarial Hepatopathy in Children Visiting a Tertiary Healthcare Hospital in Karachi

Objective To determine the frequency of malarial hepatopathy in children that are visiting Lyari General Hospital in Karachi, Pakistan. Study design Cross sectional descriptive study. Material and methods Patients with age between two months and 15 years, who had positive blood film for Plasmodium falciparum or P. vivax, were included in the study. All patients were monitored for malarial hepatopathy. Result A total of 241 cases were included in the study. Mean age at admission was 4.1 ± 1.3 years and male to female ratio was 1.2:1. There were 133 (55.2%) cases of P. vivax, while 108 (44.8%) were of P. falciparum. Malarial hepatopathy was observed in 37 patients (15.4%). Malaria hepatopathy was present in 24.1% and 8.3% children having P. falciparum and P. vivax, respectively. Malaria hepatopathy was present in 24%, 18% and 6% in age groups two months to five years, >5 years to 10 years and >10 years, respectively. Conclusion Malarial hepatopathy was observed in about one-sixth of study population and it was more common between two months and five years age group.

Associations between psychosis endophenotypes across brain functional, structural, and cognitive domains

BACKGROUND

A range of endophenotypes characterise psychosis, however there has been limited work understanding if and how they are inter-related.

METHODS

This multi-centre study includes 8754 participants: 2212 people with a psychotic disorder, 1487 unaffected relatives of probands, and 5055 healthy controls. We investigated cognition [digit span (N = 3127), block design (N = 5491), and the Rey Auditory Verbal Learning Test (N = 3543)], electrophysiology [P300 amplitude and latency (N = 1102)], and neuroanatomy [lateral ventricular volume (N = 1721)]. We used linear regression to assess the interrelationships between endophenotypes.

RESULTS

The P300 amplitude and latency were not associated (regression coef. -0.06, 95% CI -0.12 to 0.01, p = 0.060), and P300 amplitude was positively associated with block design (coef. 0.19, 95% CI 0.10-0.28, p 0.38). All the cognitive endophenotypes were associated with each other in the expected directions (all p < 0.001). Lastly, the relationships between pairs of endophenotypes were consistent in all three participant groups, differing for some of the cognitive pairings only in the strengths of the relationships.

CONCLUSIONS

The P300 amplitude and latency are independent endophenotypes; the former indexing spatial visualisation and working memory, and the latter is hypothesised to index basic processing speed. Individuals with psychotic illnesses, their unaffected relatives, and healthy controls all show similar patterns of associations between endophenotypes, endorsing the theory of a continuum of psychosis liability across the population.

Detrimental Complications Of Meconium Aspiration Syndrome And Their Impact On Outcome

BACKGROUND

Meconium aspiration syndrome (MAS) is respiratory distress in an infant born through meconium stained amniotic fluid (MSAF) whose signs cannot be otherwise explained. MAS is associated with different complications. Many studies have been conducted in developed world to find the outcome associated with MAS but data from developing countries is lacking. Present study was conducted to determine the impact of chemical pneumonitis, pulmonary hypertension (PHN) and air leak on outcome of new-borns with MAS.

METHODS

This cross sectional descriptive study was conducted in a tertiary care Neonatology unit. The babies diagnosed with MAS were included in the study. All patients were monitored for development of complications. Outcome in terms of mortality was recorded. Outcome was compared by chisquare test and p-value <0.05 is considered significant.

RESULTS

Seventy two babies were included in the study. Mean gestation was 37±0.56 weeks and birth weight was 2.87±0.49 kg. Male to female ratio was 1.57:1 and mean age of admission was 9.59±5.27 hours. Chemical pneumonitis, PHN and chemical pneumonitis with PHN were observed in 23.6%, 20.8% and 26.4% neonates respectively. Mortality rate was 19.44%. The mortality was highest in babies having chemical pneumonitis with PHN (p-value=0.013) followed by chemical pneumonitis group (p-value=0.02) and PHN group (p-value=0.032).

CONCLUSIONS

About three fourth babies with MAS developed one or more complications. Mortality is significantly increases with the development of complications so as more the complications more is the mortality.

A randomized controlled trial of mindfulness-based stress reduction to prevent flare-up in patients with inactive ulcerative colitis

BACKGROUND/AIMS

The primary therapeutic goals in ulcerative colitis (UC) are to maintain excellent quality of life (QOL) by treating flare-ups when they occur, and preventing flare-ups. Since stress can trigger UC flare-ups, we investigated the efficacy of mindfulness-based stress reduction (MBSR) to reduce flare-ups and improve QOL.

METHODS

Patients with moderately severe UC, in remission, were randomized to MBSR or time/attention control. Primary outcome was disease status. Secondary outcomes were changes in markers of inflammation and disease activity, markers of stress and psychological assessments.

RESULTS

55 subjects were randomized. Absence of flares, time to flare and severity of flare over 1 year were similar between the two groups. However, post hoc analysis showed that MBSR decreased the proportion of participants with at least one flare-up among those with top tertile urinary cortisol and baseline perceived stress (30 vs. 70%; p < 0.001). MBSR patients who flared demonstrated significantly lower stress at the last visit compared to flared patients in the control group (p = 0.04). Furthermore, MBSR prevented a drop in the Inflammatory Bowel Disease Quality of Life Questionnaire during flare (p < 0.01).

CONCLUSION

MBSR did not affect the rate or severity of flare-ups in UC patients in remission. However, MBSR might be effective for those with high stress reactivity (high perceived stress and urinary cortisol) during remission. MBSR appears to improve QOL in UC patients by minimizing the negative impact of flare-ups on QOL. Further studies are needed to identify a subset of patients for whom MBSR could alter disease course.

Initiation of osteoporosis assessment in the fracture clinic results in improved osteoporosis management: a randomised controlled trial

Osteoporosis management post fragility fracture has traditionally been deficient with up to 60-90 % of patients remaining untreated for osteoporosis in some studies. Efforts have been made to address this deficiency with some successes reported.

INTRODUCTION

The aim of this study was to assess the efficacy of two different models of screening for osteoporosis in a community fracture clinic setting.

METHODS

A prospective randomised clinical trial was conducted to assess the DXA scan and treatment rates in patients with fragility fractures when assessment for osteoporosis had been initiated in the fracture clinic compared with the "usual care" of assessment initiation by the participant's general practitioner.

RESULTS

Sixty-six patients were enrolled in the study. Thirty-three patients each were in the control and intervention groups. The assessment rate (DXA scan rate) was significantly better in the intervention group where participants were referred for assessment from fracture clinic compared to the control group where participants were referred for assessment by their general practitioner (68 vs 36 %, respectively; p < 0.05). For patients who were assessed for osteoporosis, treatment rates were similar in both the control and intervention groups (100 vs 88 %, p > 0.05).

CONCLUSION

This study demonstrates that screening for osteoporosis initiated in fracture clinic results in improved osteoporosis management compared to screening initiated in primary care. Orthopaedic surgeons and other specialists need to be more active in managing osteoporosis in patients who present with fragility fractures and should at the very least initiate assessment in the fracture clinic setting.

Mycophenolate mofetil monotherapy in the management of paediatric uveitis

PURPOSE

To evaluate effectiveness and safety of mycophenolate mofetil (MMF) monotherapy in paediatric autoimmune uveitis.

METHODS

We reviewed medical records of patients, 18 years of age or younger, with autoimmune uveitis treated with MMF at our practice from 2005 to 2009. The dose and duration of MMF therapy, inflammation status, visual acuity, previous immunomodulatory therapies, and adverse effects were recorded. In addition, the following subgroups were defined: (1) Durable Disease Control: patients whose uveitis remained quiescent for at least 2 years on MMF monotherapy, with no more than two flare-ups successfully treated with an increase in MMF dosage and/or a short course (<1 month) of corticosteroids; (2) Short-term Inflammation Control: patients whose uveitis remained quiescent for less than 2 years, with no more than one flare-up successfully treated with an increase in MMF dosage and/or a short course of corticosteroids, or who initially achieved inflammation control but discontinued MMF because of significant adverse effects.

RESULTS

A total of 38 out of 52 patients (73.1%) obtained inflammation control following 2 months of MMF monotherapy, achieving ≤ 0.5+ grading in anterior chamber cell/flare and vitreous haze. In the cross-sectional analysis, 25 patients (48.1%) met the criteria for Durable Disease Control, and 13 others (25.0%) qualified for Short-term Inflammation Control. Visual acuity remained stable or improved in 94.2% of the study population. Six patients (11.5%) discontinued MMF because of significant adverse effects, the most common of which was gastrointestinal disturbances.

CONCLUSION

MMF monotherapy appears to be an effective and safe treatment in paediatric autoimmune uveitis.

Do COMT, BDNF and NRG1 polymorphisms influence P50 sensory gating in psychosis?

BACKGROUND

Auditory P50 sensory gating deficits correlate with genetic risk for schizophrenia and constitute a plausible endophenotype for the disease. The well-supported role of catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF) and neuregulin 1 (NRG1) genes in neurodevelopment and cognition make a strong theoretical case for their influence on the P50 endophenotype.

METHOD

The possible role of NRG1, COMT Val158Met and BDNF Val66Met gene polymorphisms on the P50 endophenotype was examined in a large sample consisting of psychotic patients, their unaffected relatives and unrelated healthy controls using linear regression analyses.

RESULTS

Although P50 deficits were present in patients and their unaffected relatives, there was no evidence for an association between NRG1, COMT Val158Met or BDNF Val66Met genotypes and the P50 endophenotype.

CONCLUSIONS

The evidence from our large study suggests that any such association between P50 indices and NRG1, COMT Val158Met or BDNF Val66Met genotypes, if present, must be very subtle.

The effect of COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes on hippocampal and lateral ventricular volume in psychosis

BACKGROUND

Morphometric endophenotypes which have been proposed for psychotic disorders include lateral ventricular enlargement and hippocampal volume reductions. Genetic epidemiological studies support an overlap between schizophrenia and bipolar disorder, and COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes have been implicated in the aetiology of both these disorders. This study examined associations between these candidate genes and morphometric endophenotypes for psychosis.

METHOD

A total of 383 subjects (128 patients with psychosis, 194 of their unaffected relatives and 61 healthy controls) from the Maudsley Family Psychosis Study underwent structural magnetic resonance imaging and genotyping. The effect of candidate genes on brain morphometry was examined using linear regression models adjusting for clinical group, age, sex and correlations between members of the same family.

RESULTS

The results showed no evidence of association between variation in COMT genotype and lateral ventricular, and left or right hippocampal volumes. Neither was there any effect of the BDNF, 5-HTTLPR, NRG1 and DTNBP1 genotypes on these regional brain volumes.

CONCLUSIONS

Abnormal hippocampal and lateral ventricular volumes are among the most replicated endophenotypes for psychosis; however, the influences of COMT, BDNF, 5-HTT, NRG1 and DTNBP1 genes on these key brain regions must be very subtle if at all present.

Induced Gamma Band Deficits in Early Psychosis

Objective:

Abnormalities in event related potentials (ERPs) have long been looked at as markers of disease in Schizophrenia. Over recent years there is a trend in the field to move from averaged trials ERPs analysis in the time-voltage domain, to time-frequency single trials analysis. Oscillations in the Gamma band (30-50Hz) have received particular attention in the context of the theories of core deficits in neuronal synchronization in Schizophrenia. in this study we aimed at replicating previously found Gamma band deficits in a sample of Early Psychosis patients.

Methods:

EEG was collected from 15 patients and 15 age matched controls using an auditory oddball paradigm. Time-frequency analysis in the Gamma band was performed using a Morlet wavelet transform. We tested differences between the groups using the Wilcoxon rank sum test, given the nonparametric nature of the data, to compare each group's average single trial Gamma power, maximizing the signal-to-noise ratio.

Results:

Patients with Early Psychosis showed, following target tones, a reduction in the total power of Gamma band activation (p< 0.01) as well as in induced Gamma band activation (p< 0.01). This was observed in a late latency interval at 400-500ms. the late burst of Gamma activity was not found in the frequent condition, for neither subjects group.

Conclusion:

The findings are compatible with previous studies suggesting deficits in the late intrinsically generated cognitive processing of auditory stimuli in Schizophrenia, already present in its early stage. They add further evidence of deficits in neuronal synchronisation in the early stages of psychotic disorders.

NF-kappaB activation as a key mechanism in ethanol-induced disruption of the F-actin cytoskeleton and monolayer barrier integrity in intestinal epithelium

Intestinal barrier disruption has been implicated in several intestinal and systemic disorders including alcoholic liver disease (ALD). Using monolayers of intestinal (Caco-2) cells, we showed that ethanol (EtOH) disrupts the barrier integrity via destabilization of the cytoskeleton. Because proinflammatory conditions are associated with activation of NF-kappa B (NF-kappaB), we hypothesized that EtOH induces disruption of cytoskeletal assembly and barrier integrity by activating NF-kappaB. Parental cells were pretreated with pharmacological modulators of NF-kappaB. Other cells were stably transfected with a dominant negative mutant for the NF-kappaB inhibitor, I-kappaBalpha. Monolayers of each cell type were exposed to EtOH and we then monitored monolayer barrier integrity (permeability); cytoskeletal stability and molecular dynamics (confocal microscopy and immunoblotting); intracellular levels of the I-kappaBalpha (immunoblotting); subcellular distribution and activity of NF-kappaB (immunoblotting and sensitive ELISA); and intracellular alterations in the 43kDa protein of the actin cytoskeleton, polymerized F-actin, and monomeric G-actin (SDS-PAGE fractionation). EtOH caused destabilizing alterations, including I-kappaBalpha degradation, NF-kappaB nuclear translocation, NF-kappaB subunit (p50 and p65) activation, actin disassembly (upward arrow G-, downward arrow F-), actin cytoskeleton instability, and barrier disruption. Inhibitors of NF-kappaB and stabilizers of I-kappaBalpha (e.g., MG-132, lactacystin, etc) prevented NF-kappaB activation while protecting against EtOH-induced injury. In transfected I-kappaBalpha mutant clones, stabilization of I-kappaBalpha to inactivate NF-kappaB protected against all measures of EtOH-induced injury. Our data support several novel mechanisms where NF-kappaB can affect the molecular dynamics of the F-actin cytoskeleton and intestinal barrier integrity under conditions of EtOH injury. (1) EtOH induces disruption of the F-actin cytoskeleton and of intestinal barrier integrity, in part, through I-kappaBalpha degradation and NF-kappaB activation; (2) The mechanism underlying this pathophysiological effect of the NF-kappaB appears to involve instability of the assembly of the subunit components of actin network.

Regulation of oxidant-induced intestinal permeability by metalloprotease-dependent epidermal growth factor receptor signaling

Inflammatory bowel disease (IBD) affects more than 1 million Americans with more than 30,000 new cases diagnosed each year. IBD increases patient morbidity and susceptibility to colorectal cancer, yet its etiology remains unknown. Current models identify two key determinants of IBD pathogenesis: hyperpermeability of the gut epithelial barrier to bacterial products and an abnormal immune response to these products. Two factors seem critical for hyperpermeability: oxidant-induced stress and proinflammatory cytokines (e.g., tumor necrosis factor-alpha). The aim of this study was to investigate the role of oxidant stress-mediated transactivation of the epidermal growth factor receptor (EGFR) in intestinal hyperpermeability. This study used the Caco-2 human colonic epithelial cell in vitro model of intestinal epithelium. Cells were grown on inserts for permeability and signaling studies and glass coverslips for microscopy studies. show that oxidant-induced intestinal hyperpermeability can be blocked by specific inhibitors of the EGFR, tumor necrosis factor convertase (TACE) metalloprotease, transforming growth factor (TGF)-alpha, and mitogen-activated protein kinases, especially extracellular signal-regulated kinase 1/2. We also show that oxidant initiates these signaling events, in part by causing translocation of TACE to cell-cell contact zones. In this study, our data identify a novel mechanism for oxidant-induced intestinal hyperpermeability relevant to IBD. We propose a new intestinal permeability model in which oxidant transactivates EGFR signaling by activation of TACE and cleavage of precursor TGF-alpha. These data could have a significant effect on our view of IBD pathogenesis and provide new therapeutic targets for IBD treatment.

Do citation classics in rhinology reflect utility rather than quality?

Citation rates have been suggested to be more of an indicator of utility than quality. The aim of this study was to apply measures of utility and quality to articles identified as citation classics in rhinology/anterior skull base surgery. There were 14 articles analysed in the study. The assessment of quality was performed by combining factors from previous publications on quality assessment and the various elements were categorised into four groups; quality of written article and publication, quality of research, quality of evidence-based methodology and quality of outcome. This study revealed that citation classics in rhinology/anterior skull base surgery were well-written and satisfied peer review in reputable journals in the specialty. Quality is satisfied by clarity of exposition and patient numbers. The research was generally asking an important question and the methodology overall was adequate and appropriate for the type of study performed. A good quality of research and outcome was demonstrated with a definite historical importance, and reports that stimulated further research and enquiry. Quality is not satisfied by the lack of randomised controlled trials, appropriate statistical analysis or patient criteria. In conclusion citation rates when considered as an individual measure, reflect utility rather than quality.

theta Isoform of protein kinase C alters barrier function in intestinal epithelium through modulation of distinct claudin isotypes: a novel mechanism for regulation of permeability

Using monolayers of intestinal Caco-2 cells, we discovered that the isoform of protein kinase C (PKC), a member of the "novel" subfamily of PKC isoforms, is required for monolayer barrier function. However, the mechanisms underlying this novel effect remain largely unknown. Here, we sought to determine whether the mechanism by which PKC- disrupts monolayer permeability and dynamics in intestinal epithelium involves PKC--induced alterations in claudin isotypes. We used cell clones that we recently developed, clones that were transfected with varying levels of plasmid to either stably suppress endogenous PKC- activity (antisense, dominant-negative constructs) or to ectopically express PKC- activity (sense constructs). We then determined barrier function, claudin isotype integrity, PKC- subcellular activity, claudin isotype subcellular pools, and claudin phosphorylation. Antisense transfection to underexpress the PKC- led to monolayer instability as shown by reduced 1) endogenous PKC- activity, 2) claudin isotypes in the membrane and cytoskeletal pools ( downward arrowclaud-1, downward arrowclaud-4 assembly), 3) claudin isotype phosphorylation ( downward arrow phospho-serine, downward arrow phospho-threonine), 4) architectural stability of the claudin-1 and claudin-4 rings, and 5) monolayer barrier function. In these antisense clones, PKC- activity was also substantially reduced in the membrane and cytoskeletal cell fractions. In wild-type (WT) cells, PKC- (82 kDa) was both constitutively active and coassociated with claudin-1 (22 kDa) and claudin-4 (25 kDa), forming endogenous PKC-/claudin complexes. In a second series of studies, dominant-negative inhibition of the endogenous PKC- caused similar destabilizing effects on monolayer barrier dynamics, including claudin-1 and -4 hypophosphorylation, disassembly, and architectural instability as well as monolayer disruption. In a third series of studies, sense overexpression of the PKC- caused not only a mostly cytosolic distribution of this isoform (i.e., <12% in the membrane + cytoskeletal fractions, indicating PKC- inactivity) but also led to disruption of claudin assembly and barrier function of the monolayer. The conclusions of this study are that PKC- activity is required for normal claudin assembly and the integrity of the intestinal epithelial barrier. These effects of PKC- are mediated at the molecular level by changes in phosphorylation, membrane assembly, and/or organization of the subunit components of two barrier function proteins: claudin-1 and claudin-4 isotypes. The ability of PKC- to alter the dynamics of permeability protein claudins is a new function not previously ascribed to the novel subfamily of PKC isoforms.

theta Isoform of protein kinase C alters barrier function in intestinal epithelium through modulation of distinct claudin isotypes: a novel mechanism for regulation of permeability

Using monolayers of intestinal Caco-2 cells, we discovered that the isoform of protein kinase C (PKC), a member of the "novel" subfamily of PKC isoforms, is required for monolayer barrier function. However, the mechanisms underlying this novel effect remain largely unknown. Here, we sought to determine whether the mechanism by which PKC- disrupts monolayer permeability and dynamics in intestinal epithelium involves PKC--induced alterations in claudin isotypes. We used cell clones that we recently developed, clones that were transfected with varying levels of plasmid to either stably suppress endogenous PKC- activity (antisense, dominant-negative constructs) or to ectopically express PKC- activity (sense constructs). We then determined barrier function, claudin isotype integrity, PKC- subcellular activity, claudin isotype subcellular pools, and claudin phosphorylation. Antisense transfection to underexpress the PKC- led to monolayer instability as shown by reduced 1) endogenous PKC- activity, 2) claudin isotypes in the membrane and cytoskeletal pools ( downward arrowclaud-1, downward arrowclaud-4 assembly), 3) claudin isotype phosphorylation ( downward arrow phospho-serine, downward arrow phospho-threonine), 4) architectural stability of the claudin-1 and claudin-4 rings, and 5) monolayer barrier function. In these antisense clones, PKC- activity was also substantially reduced in the membrane and cytoskeletal cell fractions. In wild-type (WT) cells, PKC- (82 kDa) was both constitutively active and coassociated with claudin-1 (22 kDa) and claudin-4 (25 kDa), forming endogenous PKC-/claudin complexes. In a second series of studies, dominant-negative inhibition of the endogenous PKC- caused similar destabilizing effects on monolayer barrier dynamics, including claudin-1 and -4 hypophosphorylation, disassembly, and architectural instability as well as monolayer disruption. In a third series of studies, sense overexpression of the PKC- caused not only a mostly cytosolic distribution of this isoform (i.e., <12% in the membrane + cytoskeletal fractions, indicating PKC- inactivity) but also led to disruption of claudin assembly and barrier function of the monolayer. The conclusions of this study are that PKC- activity is required for normal claudin assembly and the integrity of the intestinal epithelial barrier. These effects of PKC- are mediated at the molecular level by changes in phosphorylation, membrane assembly, and/or organization of the subunit components of two barrier function proteins: claudin-1 and claudin-4 isotypes. The ability of PKC- to alter the dynamics of permeability protein claudins is a new function not previously ascribed to the novel subfamily of PKC isoforms.

Critical role of the atypical {lambda} isoform of protein kinase C (PKC-{lambda}) in oxidant-induced disruption of the microtubule cytoskeleton and barrier function of intestinal epithelium

Oxidant injury to epithelial cells and gut barrier disruption are key factors in the pathogenesis of inflammatory bowel disease. Studying monolayers of intestinal (Caco-2) cells, we reported that oxidants disrupt the cytoskeleton and cause barrier dysfunction (hyperpermeability). Because the lambda isoform of protein kinase C (PKC-lambda), an atypical diacylglycerol-independent isozyme, is abundant in parental (wild type) Caco-2 cells and is translocated to the particulate fractions upon oxidant exposure, we hypothesized that PKC-lambda is critical to oxidative injury to the assembly and architecture of cytoskeleton and the intestinal barrier function. To this end, Caco-2 cells were transfected with an inducible plasmid, a tetracycline-responsive system, to create novel clones stably overexpressing native PKC-lambda. Other cells were transfected with a dominant-negative plasmid to stably inhibit the activity of native PKC-lambda. Cells were exposed to oxidant (H(2)O(2)) +/- modulators. Parental Caco-2 cells were treated similarly. We then monitored barrier function (fluorescein sulfonic acid clearance), microtubule cytoskeletal stability (confocal microscopy, immunoblotting), subcellular distribution of PKC-lambda (immunofluorescence, immunoblotting, immunoprecipitation), and PKC-lambda isoform activity (in vitro kinase assay). Monolayers were also processed to assess alterations in tubulin assembly, polymerized tubulin (S2, an index of cytoskeletal integrity), and monomeric tubulin (S1, an index of cytoskeletal disassembly) (polyacrylamide gel electrophoresis fractionation and immunoblotting. In parental cells, oxidant caused: 1) translocation of PKC-lambda from the cytosol to the particulate (membrane + cytoskeletal) fractions, 2) activation of native PKC-lambda, 3) tubulin pool instability (increased monomeric S1 and decreased polymerized S2), 4) disruption of cytoskeletal architecture, and 5) barrier dysfunction (hyperpermeability). In transfected clones, overexpression of the atypical (74 kDa) PKC-lambda isoform by itself ( approximately 3.2-fold increase) led to oxidant-like disruptive effects, including cytoskeletal and barrier hyperpermeability. Overexpressed PKC-lambda was mostly found in particulate cell fractions (with a smaller cytosolic distribution) indicating its activation. Disruption by PKC-lambda overexpression was also potentiated by oxidant challenge. Stable inactivation of endogenous PKC-lambda ( approximately 99.6%) by a dominant-negative protected against all measures of oxidant-induced disruption. We conclude that: 1) oxidant induces disruption of epithelial barrier integrity by disassembling the cytoskeleton, in large part, through the activation of PKC-lambda isoform; and 2) activation of PKC-lambda by itself appears to be sufficient for disruption of cellular cytoskeleton and monolayer barrier permeability. The unique ability to mediate an oxidant-like injury and cytoskeletal depolymerization and instability is a novel mechanism not previously attributed to the atypical subfamily of PKC isoforms.

Novel effect of NF-kappaB activation: carbonylation and nitration injury to cytoskeleton and disruption of monolayer barrier in intestinal epithelium

Using monolayers of intestinal cells, we reported that upregulation of inducible nitric oxide synthase (iNOS) is required for oxidative injury and that activation of NF-kappaB is key to cytoskeletal instability. In the present study, we hypothesized that NF-kappaB activation is crucial to oxidant-induced iNOS upregulation and its injurious consequences: cytoskeletal oxidation and nitration and monolayer dysfunction. Wild-type (WT) cells were pretreated with inhibitors of NF-kappaB, with or without exposure to oxidant (H(2)O(2)). Other cells were transfected with an IkappaBalpha mutant (an inhibitor of NF-kappaB). Relative to WT cells exposed to vehicle, oxidant exposure caused increases in IkappaBalpha instability, NF-kappaB subunit activation, iNOS-related activity (NO, oxidative stress, tubulin nitration), microtubule disassembly and instability (increased monomeric and decreased polymeric tubulin), and monolayer disruption. Monolayers pretreated with NF-kappaB inhibitors (MG-132, lactacystin) were protected against oxidation, showing decreases in all measures of the NF-kappaB --> iNOS --> NO pathway. Dominant mutant stabilization of IkappaBalpha to inactivate NF-kappaB suppressed all measures of the iNOS/NO upregulation while protecting monolayers against oxidant insult. In these mutants, we found prevention of tubulin nitration and oxidation and enhancement of cytoskeletal and monolayer stability. We concluded that 1) NF-kappaB is required for oxidant-induced iNOS upregulation and for the consequent nitration and oxidation of cytoskeleton; 2) NF-kappaB activation causes cytoskeletal injury following upregulation of NO-driven processes; and 3) the molecular event underlying the destabilizing effects of NF-kappaB appears to be increases in carbonylation and nitrotyrosination of the subunit components of cytoskeleton. The ability to promote NO overproduction and cytoskeletal nitration/oxidation is a novel mechanism not previously attributed to NF-kappaB in cells.

Theta-isoform of PKC is required for alterations in cytoskeletal dynamics and barrier permeability in intestinal epithelium: a novel function for PKC-theta

Using intestinal Caco-2 cells, we previously showed that assembly of cytoskeleton is required for monolayer barrier function, but the underlying mechanisms remain poorly understood. Because the theta-isoform of PKC is present in wild-type (WT) intestinal cells, we hypothesized that PKC-theta is crucial for changes in cytoskeletal and barrier dynamics. We have created the first multiple sets of gastrointestinal cell clones transfected with varying levels of cDNA to stably inhibit native PKC-theta (antisense, AS; dominant negative, DN) or to express its activity (sense). We studied transfected and WT Caco-2 cells. First, relative to WT cells, AS clones underexpressing PKC-theta showed monolayer injury as indicated by decreased native PKC-theta activity, reduced tubulin phosphorylation, increased tubulin disassembly (decreased polymerized and increased monomeric pools), reduced architectural integrity of microtubules, reduced stability of occludin, and increased barrier hyperpermeability. In these AS clones, PKC-theta was substantially reduced in the particulate fractions, indicating its inactivation. In WT cells, 82-kDa PKC-theta was constitutively active and coassociated with 50-kDa tubulin, forming an endogenous PKC-theta/tubulin complex. Second, DN transfection to inhibit the endogenous PKC-theta led to similar destabilizing effects on monolayers, including cytoskeletal hypophosphorylation, depolymerization, and instability as well as barrier disruption. Third, stable overexpression of PKC-theta led to a mostly cytosolic distribution of theta-isoform (<10% in particulate fractions), indicating its inactivation. In these sense clones, we also found disruption of occludin and microtubule assembly and increased barrier dysfunction. In conclusion, 1). PKC-theta isoform is required for changes in the cytoskeletal assembly and barrier permeability in intestinal monolayers, and 2). the molecular event underlying this novel biological effect of PKC-theta involves changes in phosphorylation and/or assembly of the subunit components of the cytoskeleton. The ability to alter the cytoskeletal and barrier dynamics is a unique function not previously attributed to PKC-theta.

Inhibition of oxidant-induced nuclear factor-kappaB activation and inhibitory-kappaBalpha degradation and instability of F-actin cytoskeletal dynamics and barrier function by epidermal growth factor: key role of phospholipase-gamma isoform

Using monolayers of intestinal (Caco-2) cells as a model for studying inflammatory bowel disease (IBD), we previously showed that nuclear factor-kappaB (NF-kappaB) activation is required for oxidant-induced disruption of cytoskeletal and barrier integrity. Epidermal growth factor (EGF) stabilizes the F-actin cytoskeleton and protects against oxidant damage, but the mechanism remains unclear. We hypothesized that the mechanism involves activation of phospholipase C-gamma (PLC-gamma), which prevents NF-kappaB activation and the consequences of this activation, namely, cytoskeletal and barrier disruption. We studied wild-type and transfected cells. The latter were transfected with varying levels (1-5 microg) of cDNA to either stably overexpress PLC-gamma or to inhibit its activation. Cells were pretreated with EGF before exposure to oxidant (H(2)O(2)). Stably overexpressing PLC-gamma (+2.0-fold) or preincubating with EGF protected against oxidant injury as indicated by 1) decreases in several NF-kappaB-related variables [NF-kappaB (p50/p65 subunit) nuclear translocation, NF-kappaB subunit activity, inhibitory-kappaBalpha (I-kappaBalpha) phosphorylation and degradation]; 2) increases in F-actin and decreases in G-actin; 3) stabilization of the actin cytoskeletal architecture; and 4) enhancement of barrier function. Overexpression induced inactivation of NF-kappaB was potentiated by EGF. PLC-gamma was found mostly in membrane and cytoskeletal fractions (<9% in the cytosolic fractions), indicating its activation. Dominant negative inhibition of endogenous PLC-gamma (-99%) substantially prevented all measures of EGF protection against NF-kappaB activation. We concluded 1) EGF protects against oxidant-induced barrier disruption through PLC-gamma activation, which inactivates NF-kappaB; 2) Activation of PLC-gamma by itself is protective against NF-kappaB activation; 3) the ability to modulate the dynamics of NF-kappaB/I-kappa Balpha is a novel mechanism not previously attributed to the PLC family of isoforms in cells; and 4) development of PLC-gamma mimetics represents a possible new therapeutic strategy for IBD.

PKC-beta1 isoform activation is required for EGF-induced NF-kappaB inactivation and IkappaBalpha stabilization and protection of F-actin assembly and barrier function in enterocyte monolayers

Using monolayers of intestinal Caco-2 cells, we reported that activation of NF-kappaB is required for oxidative disruption and that EGF protects against this injury but the mechanism remains unclear. Activation of the PKC-beta1 isoform is key to monolayer barrier integrity. We hypothesized that EGF-induced activation of PKC-beta1 prevents oxidant-induced activation of NF-kappaB and the consequences of NF-kappaB activation, F-actin, and barrier dysfunction. We used wild-type (WT) and transfected cells. The latter were transfected with varying levels of cDNA to overexpress or underexpress PKC-beta1. Cells were pretreated with EGF or PKC modulators +/- oxidant. Pretreatment with EGF protected monolayers by increasing native PKC-beta1 activity, decreasing IkappaBalpha phosphorylation/degradation, suppressing NF-kappaB activation (p50/p65 subunit nuclear translocation/activity), enhancing stable actin (increased F-actin-to-G-actin ratio), increasing stability of actin cytoskeleton, and reducing barrier hyperpermeability. Cells stably overexpressing PKC-beta1 were protected by low, previously nonprotective doses of EGF or modulators. In these clones, we found enhanced IkappaBalpha stabilization, NF-kappaB inactivation, actin stability, and barrier function. Low doses of the modulators led to increases in PKC-beta1 in the particulate fractions, indicating activation. Stably inhibiting endogenous PKC-beta1 substantially prevented all measures of EGF's protection against NF-kappaB activation. We conclude that EGF-mediated protection against oxidant disruption of the intestinal barrier function requires PKC-beta1 activation and NF-kappaB suppression. The molecular event underlying this unique effect of PKC-beta1 involves inhibition of phosphorylation and increases in stabilization of IkappaBalpha. The ability to inhibit the dynamics of NF-kappaB/IkappaBalpha and F-actin disassembly is a novel mechanism not previously attributed to the classic subfamily of PKC isoforms.

Key role of PLC-gamma in EGF protection of epithelial barrier against iNOS upregulation and F-actin nitration and disassembly

Upregulation of inducible nitric oxide synthase (iNOS) is key to oxidant-induced disruption of intestinal (Caco-2) monolayer barrier, and EGF protects against this disruption by stabilizing the cytoskeleton. PLC-gamma appears to be essential for monolayer integrity. We thus hypothesized that PLC-gamma activation is essential in EGF protection against iNOS upregulation and the consequent cytoskeletal oxidation and disarray and monolayer disruption. Intestinal cells were transfected to stably overexpress PLC-gamma or to inhibit its activation and were then pretreated with EGF +/- oxidant (H2O2). Wild-type (WT) intestinal cells were treated similarly. Relative to WT monolayers exposed to oxidant, pretreatment with EGF protected monolayers by: increasing native PLC-gamma activity; decreasing six iNOS-related variables (iNOS activity/protein, NO levels, oxidative stress, actin oxidation/nitration); increasing stable F-actin; maintaining actin stability; and enhancing barrier integrity. Relative to WT cells exposed to oxidant, transfected monolayers overexpressing PLC-gamma (+2.3-fold) were protected, as indicated by decreases in all measures of iNOS-driven pathway and enhanced actin and barrier integrity. Overexpression-induced inhibition of iNOS was potentiated by low doses of EGF. Stable inhibition of PLC-gamma prevented all measures of EGF protection against iNOS upregulation. We conclude that 1) EGF protects against oxidative stress disruption of intestinal barrier by stabilizing F-Actin, largely through the activation of PLC-gamma and downregulation of iNOS pathway; 2) activation of PLC-gamma is by itself essential for cellular protection against oxidative stress of iNOS; and 3) the ability to suppress iNOS-driven reactions and cytoskeletal oxidation and disassembly is a novel mechanism not previously attributed to the PLC family of isoforms.

Zeta isoform of protein kinase C prevents oxidant-induced nuclear factor-kappaB activation and I-kappaBalpha degradation: a fundamental mechanism for epidermal growth factor protection of the microtubule cytoskeleton and intestinal barrier integrity

Oxidant damage and gut barrier disruption contribute to the pathogenesis of a variety of inflammatory gastrointestinal disorders, including inflammatory bowel disease (IBD). In our studies using a model of the gastrointestinal (GI) epithelial barrier, monolayers of intestinal (Caco-2) cells, we investigated damage to and protection of the monolayer barrier. We reported that activation of nuclear factor-kappaB (NF-kappaB) via degradation of its endogenous inhibitor I-kappaBalpha is key to oxidant-induced disruption of barrier integrity and that growth factor (epidermal growth factor, EGF) protects against this injury by stabilizing the cytoskeletal filaments. Protein kinase C (PKC) activation seems to be required for monolayer maintenance, especially activation of the atypical zeta isoform of PKC. In an attempt to investigate, at the molecular level, the fundamental events underlying EGF protection against oxidant disruption, we tested the intriguing hypothesis that EGF-induced activation of PKC-zeta prevents oxidant-induced activation of NF-kappaB and the consequences of NF-kappaB activation, namely, cytoskeletal and barrier disruption. Monolayers of wild-type (WT) Caco-2 cells were incubated with oxidant (H2O2) with or without EGF or modulators. In other studies, we used the first gastrointestinal cell clones created by stable transfection of varying levels (1-5 microg) of cDNA to either overexpress PKC-zeta or to inhibit its expression. Transfected cell clones were then pretreated with EGF or a PKC activator (diacylglycerol analog 1-oleoyl-2-acetyl-glycerol, OAG) before oxidant. We monitored the following endpoints: monolayer barrier integrity, stability of the microtubule cytoskeleton, subcellular distribution and activity of the PKC-zeta isoform, intracellular levels and phosphorylation of the NF-kappaB inhibitor I-kappaBalpha, and nuclear translocation and activity of NF-kappaB subunits p65 and p50. Monolayers were also fractionated and processed to assess alterations in the structural protein of the microtubules, polymerized tubulin (S2), and monomeric tubulin (S1). Our data indicated that relative to WT monolayers exposed only to oxidant, pretreatment with EGF protected cell monolayers by 1) increasing native PKC-zeta activity; 2) decreasing several variables related to NF-kappaB activation [NF-kappaB (both p50 and p65 subunits) nuclear translocation, NF-kappaB subunits activity, I-kappaBalpha degradation, and phosphorylation]; 3) increasing stable tubulin (increased polymerized S2 tubulin and decreased monomeric S1 tubulin); 4) maintaining the cytoarchitectural integrity of microtubules; and 5) preventing hyperpermeability (barrier disruption). In addition, relative to WT cells exposed to oxidant, monolayers of transfected cells stably overexpressing PKC-zeta (approximately 3.0-fold increase) were protected as indicated by decreases in all measures of NF-kappaB activation as well as enhanced stability of microtubule cytoarchitecture and barrier function. Overexpression induced stabilization of I-kappaBalpha and inactivation of NF-kappaB was OAG-independent, although EGF potentiated this protection. Approximately 90% of the overexpressed PKC-zeta resided in particulate (membrane + cytoskeletal) fractions (with less than 10% in cytosolic fractions), indicating constitutive activation of the zeta isoform of PKC. Furthermore, antisense transfection to stably inhibit native PKC-zeta expression (-95%) and activation (-99%) prevented all measures of EGF-induced protection against NF-kappaB activation and monolayer disruption. We conclude the following: 1) EGF protects against oxidant disruption of the intestinal barrier integrity, in large part, through the activation of PKC-zeta and inactivation of NF-kappaB (an inflammatory mediator); 2) activation of PKC-zeta is by itself required for monolayer protection against oxidant stress of NF-kappaB activation; 3) the mechanism underlying this novel biological effect of the atypical PKC isoform zeta seems to involve suppression of phosphorylation and enhancement of stabilization of I-kappaBalpha; and 4) development of agents that can mimic or enhance PKC-zeta-induced suppression of NF-kappaB activation may be a useful therapeutic strategy for preventing oxidant damage to GI mucosal epithelium in disorders such as IBD. To our knowledge, this is the first report that PKC-zeta can inhibit the dynamics of NF-kappaB and cytoskeletal disassembly in cells.

The delta-isoform of protein kinase C causes inducible nitric-oxide synthase and nitric oxide up-regulation: key mechanism for oxidant-induced carbonylation, nitration, and disassembly of the microtubule cytoskeleton and hyperpermeability of barrier of intestinal epithelia

Using intestinal (Caco-2) cells, we found that oxidant-induced disruption of barrier integrity requires microtubule disassembly. Protein kinase C (PKC)-delta isoform seems to be essential for disruption, but the mechanism is unknown. Because inducible nitric-oxide synthase (iNOS) is key to oxidant stress, we hypothesized that PKC-delta activation is essential in oxidant-induced iNOS up-regulation and the consequent cytoskeletal oxidation and disarray and monolayer barrier dysfunction. Cells were transfected with an inducible plasmid to overexpress native PKC-delta or with a dominant-negative to inhibit the activity of native PKC-delta. Clones were then incubated with oxidant (H(2)O(2)) +/- modulators. Parental cells were treated similarly. Exposure to oxidant-disrupted monolayers by increasing native PKC-delta activity, increasing six iNOS-related variables (iNOS activity and protein, nitric oxide, oxidative stress, tubulin oxidation and nitration), decreasing polymerized tubulin, disrupting the cytoarchitecture of microtubules, and causing monolayer dysfunction. Induction of PKC-delta overexpression by itself (3.5-fold) led to oxidant-like disruptive effects, including activation of the iNOS-driven pathway. Overexpression-induced up-regulation of iNOS was potentiated by oxidants. iNOS inhibitors or oxidant scavengers were protective. Dominant inhibition of native PKC-delta activity (99.5%) prevented all measures of oxidant-induced iNOS up-regulation and protected the monolayer barrier. The conclusions are as follows. 1) Oxidants induce loss of epithelial barrier integrity by oxidizing and disassembling the cytoskeleton, in part, through the activation of PKC-delta and up-regulation of iNOS. 2) Overexpression and activation of PKC-delta are by themselves key for cellular injury by oxidative stress of iNOS. 3) We thus report a pathophysiological mechanism, activation of iNOS pathway and its injurious consequences to the cytoskeleton, including oxidation and nitration, among the "novel" subfamily of PKC isoforms.

Muscle activity and jaw movements as predictors of chewing performance

Chewing performance can be defined in terms of the reduction in food particle size after 15 chewing strokes. In this study, the relationship between chewing performance and electromyographic activity was investigated to develop optimal values of electromyographic variables, based on their ability to predict chewing performance. Electrognathographic and electromyographic recordings from surface electrodes over the digastric (abductor), masseter, and temporalis (adductors) muscles were made from 24 subjects while they chewed a hard fruit gum. A moderate negative correlation was found between the food particle size and the root mean square calculation for masseter activity (-.48; P < .01). Weaker positive correlations were found between particle size and the asynchrony of ipsilateral and contralateral anterior temporalis muscles (.36; P < .05). A multiple regression model of electromyographic and electrognathographic variables was able to predict chewing performance with an R2 value of .66. If chewing performance is used as an output measure of masticatory function, it may be possible to determine optimal ranges for electromyographic variables and jaw movements.

Jaw movement tremor as a predictor of chewing performance

The purpose of this study was to investigate normal physiologic tremor in jaw movement as a factor that may influence chewing performance more directly than either muscle activity or jaw displacement. Chewing performance was defined in terms of the reduction in food particle size after 15 chewing strokes. Data on chewing particle size and electromyographic activity were available for 24 asymptomatic adults from an earlier study. Jaw movements during chewing were recorded using electrognathography, and velocity and acceleration in three planes were determined. Power spectrum for acceleration was calculated during opening and closing phases of the chewing cycle. The frequency of the peak amplitude in the power spectrum represented physiologic tremor of the jaw. Tremor frequencies during both opening and closing phases of the chewing cycle were strong predictors of chewing performance. A multivariate model composed of variables derived from acceleration, together with electromyographic and jaw movement variables, produced a multivariate model that was able to predict chewing performance with an adjusted R2 value of .78.