Inhibition of STAT-mediated cytokine responses to chemically-induced colitis prevents inflammation-associated neurobehavioral impairments

Depression can be associated with chronic systemic inflammation, and production of peripheral proinflammatory cytokines and upregulation of the kynurenine pathway have been implicated in pathogenesis of depression. However, the mechanistic bases for these comorbidities are not yet well understood. As tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO), which convert tryptophan to kynurenine, are rate-limiting enzymes of the kynurenine pathway, we screened TDO or IDO inhibitors for effects on the production of proinflammatory cytokines in a mouse macrophage cell line. The TDO inhibitor 680C91 attenuated LPS-induced pro-inflammatory cytokines including IL-1β and IL-6. Surprisingly, this effect was TDO-independent, as it occurred even in peritoneal macrophages from TDO knockout mice. Instead, the anti-inflammatory effects of 680C91 were mediated through the suppression of signal transducer and activator of transcription(STAT) signaling. Furthermore, 680C91 suppressed production of proinflammatory cytokines and STAT signaling in an animal model of inflammatory bowel disease. Specifically, 680C91 effectively attenuated acute phase colon cytokine responses in male mice subjected to dextran sulfate sodium (DSS)-induced colitis. Interestingly, this treatment also prevented the development of anxiodepressive-like neurobehaviors in DSS-treated mice during the recovery phase. The ability of 680C91 to prevent anxiodepressive-like behavior in response to chemically-induced colitis appeared to be due to rescue of attenuated dopamine responses in the nucleus accumbens. Thus, inhibition of STAT-mediated, but TDO-independent proinflammatory cytokines in macrophages can prevent inflammation-associated anxiety and depression. Identification of molecular mechanisms involved may facilitate the development of new treatments for gastrointestinal-neuropsychiatric comorbidity.

Comparison of the diagnostic yield of transbronchial lung biopsies by forceps and cryoprobe in diffuse parenchymal lung disease

Background

Transbronchial lung cryobiopsy (TBLC) in the diagnosis of diffuse parenchymal lung disease (DPLD) has shown a promising yield in recent times, with low post-procedural mortality and morbidity.

Objectives

To compare the yield of TBLC and conventional transbronchial forceps lung biopsy (TBLB).

Methods

A prospective study was carried out in patients with DPLD over a period of 1 year in a tertiary respiratory care institute in New Delhi, India. All 87 patients enrolled underwent both TBLB and TBLC. The procedures were performed in the bronchoscopy suite under conscious sedation and local anaesthesia, with an attempt to take a minimum of three biopsy specimens by conventional TBLB followed by TBLC. A 1.9 mm cryoprobe with a freezing time of 4 - 5 seconds was used. An Arndt endobronchial blocker was used to control bleeding along with locally administered medications.

Results

TBLB and TBLC led to a definitive diagnosis in 27 (31.0%) and 69 (79.3%) cases, respectively. The commonest diagnoses were hypersensitivity pneumonitis, sarcoidosis and pulmonary tuberculosis. TBLC led to additional diagnoses in 42 cases (48.3%). Pneumothorax was observed in 12 cases (13.8%), and moderate bleeding occurred in 63 (72.4%). There were no procedure-related deaths.

Conclusion

TBLC had a better diagnostic yield than conventional TBLB in DPLD. It has the potential to become a safe day-care procedure in a resource-limited setting, if certain precautions are taken.

Study synopsis

What the study adds. Compared with transbronchial forceps lung biopsy, transbronchial lung cryobiopsy (TBLC) led to additional diagnoses in 42 (48.3%) of 87 patients with clinicoradiological features of diffuse parenchymal lung disease. Pneumothorax was observed in 12 cases (13.8%) and moderate bleeding in 63 (72.4%). TBLC without rigid bronchoscopy or advanced airway devices under conscious sedation had a good diagnostic yield with an acceptable adverse events profile.Implications of the findings. TBLC under conscious sedation is not resource intensive and can be carried out in settings with limited resources.

Cdk5 mediates rotational force-induced brain injury

Millions of traumatic brain injuries (TBIs) occur annually. TBIs commonly result from falls, traffic accidents, and sports-related injuries, all of which involve rotational acceleration/deceleration of the brain. During these injuries, the brain endures a multitude of primary insults including compression of brain tissue, damaged vasculature, and diffuse axonal injury. All of these deleterious effects can contribute to secondary brain ischemia, cellular death, and neuroinflammation that progress for weeks, months, and lifetime after injury. While the linear effects of head trauma have been extensively modeled, less is known about how rotational injuries mediate neuronal damage following injury. Here, we developed a new model of repetitive rotational head trauma in rodents and demonstrated acute and prolonged pathological, behavioral, and electrophysiological effects of rotational TBI (rTBI). We identify aberrant Cyclin-dependent kinase 5 (Cdk5) activity as a principal mediator of rTBI. We utilized Cdk5-enriched phosphoproteomics to uncover potential downstream mediators of rTBI and show pharmacological inhibition of Cdk5 reduces the cognitive and pathological consequences of injury. These studies contribute meaningfully to our understanding of the mechanisms of rTBI and how they may be effectively treated.

A modified standard American diet induces physiological parameters associated with metabolic syndrome in C57BL/6J mice

Investigations into the causative role that western dietary patterns have on obesity and disease pathogenesis have speculated that quality and quantity of dietary fats and/or carbohydrates have a predictive role in the development of these disorders. Standard reference diets such as the AIN-93 rodent diet have historically been used to promote animal health and reduce variation of results across experiments, rather than model modern human dietary habits or nutrition-related pathologies. In rodents high-fat diets (HFDs) became a classic tool to investigate diet-induced obesity (DIO). These murine diets often relied on a single fat source with the most DIO consistent HFDs containing levels of fat up to 45-60% (kcal), higher than the reported human intake of 33-35% (kcal). More recently, researchers are formulating experimental animal (pre-clinical) diets that reflect mean human macro- and micronutrient consumption levels described by the National Health and Nutrition Examination Survey (NHANES). These diets attempt to integrate relevant ingredient sources and levels of nutrients; however, they most often fail to include high-fructose corn syrup (HFCS) as a source of dietary carbohydrate. We have formulated a modified Standard American Diet (mSAD) that incorporates relevant levels and sources of nutrient classes, including dietary HFCS, to assess the basal physiologies associated with mSAD consumption. Mice proffered the mSAD for 15 weeks displayed a phenotype consistent with metabolic syndrome, exhibiting increased adiposity, fasting hyperglycemia with impaired glucose and insulin tolerance. Metabolic alterations were evidenced at the tissue level as crown-like structures (CLS) in adipose tissue and fatty acid deposition in the liver, and targeted 16S rRNA metagenomics revealed microbial compositional shifts between dietary groups. This study suggests diet quality significantly affects metabolic homeostasis, emphasizing the importance of developing relevant pre-clinical diets to investigate chronic diseases highly impacted by western dietary consumption patterns.

Integrated regulation of PKA by fast and slow neurotransmission in the nucleus accumbens controls plasticity and stress responses

Cortical glutamate and midbrain dopamine neurotransmission converge to mediate striatum-dependent behaviors, while maladaptations in striatal circuitry contribute to mental disorders. However, the crosstalk between glutamate and dopamine signaling has not been entirely elucidated. Here we uncover a molecular mechanism by which glutamatergic and dopaminergic signaling integrate to regulate cAMP-dependent protein kinase (PKA) via phosphorylation of the PKA regulatory subunit, RIIβ. Using a combination of biochemical, pharmacological, neurophysiological, and behavioral approaches, we find that glutamate-dependent reduction in cyclin-dependent kinase 5 (Cdk5)-dependent RIIβ phosphorylation alters the PKA holoenzyme autoinhibitory state to increase PKA signaling in response to dopamine. Furthermore, we show that disruption of RIIβ phosphorylation by Cdk5 enhances cortico-ventral striatal synaptic plasticity. In addition, we demonstrate that acute and chronic stress in rats inversely modulate RIIβ phosphorylation and ventral striatal infusion of a small interfering peptide that selectively targets RIIβ regulation by Cdk5 improves behavioral response to stress. We propose this new signaling mechanism integrating ventral striatal glutamate and dopamine neurotransmission is important to brain function, may contribute to neuropsychiatric conditions, and serves as a possible target for the development of novel therapeutics for stress-related disorders.

Systemic Administration of a Brain Permeable Cdk5 Inhibitor Alters Neurobehavior

Cyclin-dependent kinase 5 (Cdk5) is a crucial regulator of neuronal signal transduction. Cdk5 activity is implicated in various neuropsychiatric and neurodegenerative conditions such as stress, anxiety, depression, addiction, Alzheimer's disease, and Parkinson's disease. While constitutive Cdk5 knockout is perinatally lethal, conditional knockout mice display resilience to stress-induction, enhanced cognition, neuroprotection from stroke and head trauma, and ameliorated neurodegeneration. Thus, Cdk5 represents a prime target for treatment in a spectrum of neurological and neuropsychiatric conditions. While intracranial infusions or treatment of acutely dissected brain tissue with compounds that inhibit Cdk5 have allowed the study of kinase function and corroborated conditional knockout findings, potent brain-penetrant systemically deliverable Cdk5 inhibitors are extremely limited, and no Cdk5 inhibitor has been approved to treat any neuropsychiatric or degenerative diseases to date. Here, we screened aminopyrazole-based analogs as potential Cdk5 inhibitors and identified a novel analog, 25-106, as a uniquely brain-penetrant anti-Cdk5 drug. We characterize the pharmacokinetic and dynamic responses of 25-106 in mice and functionally validate the effects of Cdk5 inhibition on open field and tail-suspension behaviors. Altogether, 25-106 represents a promising preclinical Cdk5 inhibitor that can be systemically administered with significant potential as a neurological/neuropsychiatric therapeutic.

RORγt-Expressing Pathogenic CD4+ T Cells Cause Brain Inflammation during Chronic Colitis

Neurobehavioral disorders and brain abnormalities have been extensively reported in both Crohn's disease and ulcerative colitis patients. However, the mechanism causing neuropathological disorders in inflammatory bowel disease patients remains unknown. Studies have linked the Th17 subset of CD4⁺ T cells to brain diseases associated with neuroinflammation and cognitive impairment, including multiple sclerosis, ischemic brain injury, and Alzheimer's disease. To better understand how CD4⁺ T lymphocytes contribute to brain pathology in chronic intestinal inflammation, we investigated the development of brain inflammation in the T cell transfer model of chronic colitis. Our findings demonstrate that CD4⁺ T cells infiltrate the brain of colitic Rag1 ^-/- mice in proportional levels to colitis severity. Colitic mice developed hypothalamic astrogliosis that correlated with neurobehavioral disorders. Moreover, the brain-infiltrating CD4⁺ T cells expressed Th17 cell transcription factor retinoic acid-related orphan receptor γt (RORγt) and displayed a pathogenic Th17 cellular phenotype similar to colonic Th17 cells. Adoptive transfer of RORγt-deficient naive CD4⁺ T cells failed to cause brain inflammation and neurobehavioral disorders in Rag1 ^-/- recipients, with significantly less brain infiltration of CD4⁺ T cells. The finding is mirrored in chronic dextran sulfate sodium-induced colitis in Rorc^fl/fl Cd4-Cre mice that showed lower frequency of brain-infiltrating CD4⁺ T cells and astrogliosis despite onset of significantly more severe colitis compared with wild-type mice. These findings suggest that pathogenic RORγt⁺CD4⁺ T cells that aggravate colitis migrate preferentially into the brain, contributing to brain inflammation and neurobehavioral disorders, thereby linking colitis severity to neuroinflammation.

Association of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Ureaplasma species infection and organism load with cervicitis in north Indian population

Cervicitis is predominantly caused by Neisseria gonorrhoeae and Chlamydia trachomatis, which accounts for almost half of all the cases of cervicitis. The role of newer organisms like Mycoplasma genitalium and Ureaplasma sp. and association of bacterial load with cervicitis are also not well established. So the study aimed to determine the relative frequency of these organisms and their load in association with cervicitis cases from north India. A case-control study involving 300 women was conducted using quantitative real-time PCR from endocervical swabs for identification of organisms and quantification of bacterial load. Among 150 cervicitis cases, C. trachomatis, N. gonorrhoeae, M. genitalium and Ureaplasma parvum were detected in 5 (3·3%), 10 (6·6%), 37(24·6%) and 47 (31·3%) respectively. Old age (<0·001, chi-squared test) and irregular menstrual cycles (<0·001, chi-squared test) were significantly associated with cervicitis. M genitalium was the only organism to be associated significantly with cervicitis with regard to age (<0·031) and symptoms like discharge (P < 0·033, chi-squared test) and dysuria (P < 0·044, chi-squared test) in multivariate analysis. Our finding suggests that the bacterial load of these organisms is not significantly associated with cervicitis. However, we found significant association of M. genitalium infection with clinical characteristics of cervicitis cases.

High Fructose Corn Syrup-Moderate Fat Diet Potentiates Anxio-Depressive Behavior and Alters Ventral Striatal Neuronal Signaling

The neurobiological mechanisms that mediate psychiatric comorbidities associated with metabolic disorders such as obesity, metabolic syndrome and diabetes remain obscure. High fructose corn syrup (HFCS) is widely used in beverages and is often included in food products with moderate or high fat content that have been linked to many serious health issues including diabetes and obesity. However, the impact of such foods on the brain has not been fully characterized. Here, we evaluated the effects of long-term consumption of a HFCS-Moderate Fat diet (HFCS-MFD) on behavior, neuronal signal transduction, gut microbiota, and serum metabolomic profile in mice to better understand how its consumption and resulting obesity and metabolic alterations relate to behavioral dysfunction. Mice fed HFCS-MFD for 16 weeks displayed enhanced anxiogenesis, increased behavioral despair, and impaired social interactions. Furthermore, the HFCS-MFD induced gut microbiota dysbiosis and lowered serum levels of serotonin and its tryptophan-based precursors. Importantly, the HFCS-MFD altered neuronal signaling in the ventral striatum including reduced inhibitory phosphorylation of glycogen synthase kinase 3β (GSK3β), increased expression of ΔFosB, increased Cdk5-dependent phosphorylation of DARPP-32, and reduced PKA-dependent phosphorylation of the GluR1 subunit of the AMPA receptor. These findings suggest that HFCS-MFD-induced changes in the gut microbiota and neuroactive metabolites may contribute to maladaptive alterations in ventral striatal function that underlie neurobehavioral impairment. While future studies are essential to further evaluate the interplay between these factors in obesity and metabolic syndrome-associated behavioral comorbidities, these data underscore the important role of peripheral-CNS interactions in diet-induced behavioral and brain function. This study also highlights the clinical need to address neurobehavioral comorbidities associated with obesity and metabolic syndrome.

HMGB1: A Common Biomarker and Potential Target for TBI, Neuroinflammation, Epilepsy, and Cognitive Dysfunction

High mobility group box protein 1 (HMGB1) is a ubiquitous nuclear protein released by glia and neurons upon inflammasome activation and activates receptor for advanced glycation end products (RAGE) and toll-like receptor (TLR) 4 on the target cells. HMGB1/TLR4 axis is a key initiator of neuroinflammation. In recent days, more attention has been paid to HMGB1 due to its contribution in traumatic brain injury (TBI), neuroinflammatory conditions, epileptogenesis, and cognitive impairments and has emerged as a novel target for those conditions. Nevertheless, HMGB1 has not been portrayed as a common prognostic biomarker for these HMGB1 mediated pathologies. The current review discusses the contribution of HMGB1/TLR4/RAGE signaling in several brain injury, neuroinflammation mediated disorders, epileptogenesis and cognitive dysfunctions and in the light of available evidence, argued the possibilities of HMGB1 as a common viable biomarker of the above mentioned neurological dysfunctions. Furthermore, the review also addresses the result of preclinical studies focused on HMGB1 targeted therapy by the HMGB1 antagonist in several ranges of HMGB1 mediated conditions and noted an encouraging result. These findings suggest HMGB1 as a potential candidate to be a common biomarker of TBI, neuroinflammation, epileptogenesis, and cognitive dysfunctions which can be used for early prediction and progression of those neurological diseases. Future study should explore toward the translational implication of HMGB1 which can open the windows of opportunities for the development of innovative therapeutics that could prevent several associated HMGB1 mediated pathologies discussed herein.

Vascular endothelial growth factor: Evidence for autocrine signaling in hepatocellular carcinoma cell lines affecting invasion

BACKGROUND AND AIM

Vascular endothelial growth factor (VEGF) is a well-known pivotal regulator of tumor angiogenesis. Apart from endothelial cells, it is also expressed in nonendothelial cells, including tumor cells themselves. Hence the aim of this study was to investigate the autocrine effects of VEGF in hepatocellular carcinoma (HCC) -derived cell lines.

MATERIALS AND METHODS

Two hepatocellular carcinoma cell lines (Hep3B and HepG2) were screened for expression of VEGF by quantitative real-time polymerase chain reaction (PCR) and its receptors VEGF-R1, VEGF-R2, and neuropilin-1 expression by reverse transcriptase-PCR, respectively. Furthermore, VEGF transcript was silenced by siRNA and the effects on cell migration, viability, and proliferation were determined by the wound healing assay, MTT assay, and propidium iodide staining, respectively.

RESULTS

Both Hep3B and HepG2 cell lines expressed VEGF and all the three receptors at high levels. VEGF siRNA inhibited VEGF expression significantly in both Hep3B and HepG2 cell lines. Silencing of VEGF showed decreased migration in the Hep3B cell line. In both cell lines tested, there was decreased cell viability but no effect on cellular proliferation.

CONCLUSION

Our data indicates that autocrine signaling of VEGF through its receptors exists in HCC cell lines, which has important implications for tumor invasion, metastasis, and for designing interventional strategies.

Effect of behavioral testing on spine density of basal dendrites in the CA1 region of the hippocampus modulated by (56)Fe irradiation

A unique feature of the space radiation environment is the presence of high-energy charged particles, including (56)Fe ions, which can present a significant hazard to space flight crews during and following a mission. (56)Fe irradiation-induced cognitive changes often involve alterations in hippocampal function. These alterations might involve changes in spine morphology and density. In addition to irradiation, performing a cognitive task can also affect spine morphology. Therefore, it is often hard to determine whether changes in spine morphology and density are due to an environmental challenge or group differences in performance on cognitive tests. In this study, we tested the hypothesis that the ability of exploratory behavior to increase specific measures of hippocampal spine morphology and density is affected by (56)Fe irradiation. In sham-irradiated mice, exploratory behavior increased basal spine density in the CA1 region of the hippocampus and the enclosed blade of the dentate gyrus. These effects were not seen in irradiated mice. In addition, following exploratory behavior, there was a trend toward a decrease in the percent stubby spines on apical dendrites in the CA3 region of the hippocampus in (56)Fe-irradiated, but not sham-irradiated, mice. Other hippocampal regions and spine measures affected by (56)Fe irradiation showed comparable radiation effects in behaviorally naïve and cognitively tested mice. Thus, the ability of exploratory behavior to alter spine density and morphology in specific hippocampal regions is affected by (56)Fe irradiation.

Radiation exposure prior to traumatic brain injury induces responses that differ as a function of animal age

Purpose:

Uncontrolled radiation exposure due to radiological terrorism, industrial accidents or military circumstances is a continuing threat for the civilian population. Age plays a major role in the susceptibility to radiation; younger children are at higher risk of developing cognitive deterioration when compared to adults. Our objective was to determine if an exposure to radiation affected the vulnerability of the juvenile hippocampus to a subsequent moderate traumatic injury.

Materials and methods:

Three-week-old (juvenile) and eight-week-old young adult C57BL/J6 male mice received whole body cesium-137 (¹³⁷Cs) irradiation with 4 gray (Gy). One month later, unilateral traumatic brain injury was induced using a controlled cortical impact system. Two months post-irradiation, animals were tested for hippocampus-dependent cognitive performance in the Morris water-maze. After cognitive testing, animals were euthanized and their brains frozen for immunohistochemical assessment of activated microglia and neurogenesis in the hippocampal dentate gyrus.

Results:

All animals were able to learn the water maze task; however, treatment effects were seen when spatial memory retention was assessed. Animals that received irradiation as juveniles followed by a moderate traumatic brain injury one month later did not show spatial memory retention, i.e., were cognitively impaired. In contrast, all groups of animals that were treated as adults showed spatial memory retention in the probe trials.

Conclusion:

Although the mechanisms involved are not clear, our results suggest that irradiation enhanced a young animal's vulnerability to develop cognitive injury following a subsequent traumatic injury.

Cranial irradiation alters dendritic spine density and morphology in the hippocampus

Therapeutic irradiation of the brain is a common treatment modality for brain tumors, but can lead to impairment of cognitive function. Dendritic spines are sites of excitatory synaptic transmission and changes in spine structure and number are thought to represent a morphological correlate of altered brain functions associated with hippocampal dependent learning and memory. To gain some insight into the temporal and sub region specific cellular changes in the hippocampus following brain irradiation, we investigated the effects of 10 Gy cranial irradiation on dendritic spines in young adult mice. One week or 1 month post irradiation, changes in spine density and morphology in dentate gyrus (DG) granule and CA1 pyramidal neurons were quantified using Golgi staining. Our results showed that in the DG, there were significant reductions in spine density at both 1 week (11.9%) and 1 month (26.9%) after irradiation. In contrast, in the basal dendrites of CA1 pyramidal neurons, irradiation resulted in a significant reduction (18.7%) in spine density only at 1 week post irradiation. Analysis of spine morphology showed that irradiation led to significant decreases in the proportion of mushroom spines at both time points in the DG as well as CA1 basal dendrites. The proportions of stubby spines were significantly increased in both the areas at 1 month post irradiation. Irradiation did not alter spine density in the CA1 apical dendrites, but there were significant changes in the proportion of thin and mushroom spines at both time points post irradiation. Although the mechanisms involved are not clear, these findings are the first to show that brain irradiation of young adult animals leads to alterations in dendritic spine density and morphology in the hippocampus in a time dependent and region specific manner.

Involvement of nitric oxide in the protective effects of dehydroepiandrosterone sulphate on stress induced neurobehavioral suppression and brain oxidative injury in rats

The involvement of nitric oxide (NO) in the effects of dehydroepiandrosterone sulphate (DHEAS) on restraint stress induced neurobehavioral and brain oxidative/nitrosative stress markers was investigated in rats. Exposure of rats to restraint stress suppressed behavioral activity in the elevated plus maze and this was associated with increases in malondialdehyde (MDA) and decrease in reduced glutathione (GSH) and brain NO metabolite (NOx) levels in brain homogenates. Pretreatment with DHEAS (5-40mg/s.c.) reversed the stress induced changes in behavioral and oxidative stress markers and also brain NOx levels. The beneficial effect of DHEAS (40mg/kgs.c.) was blocked by pretreatment with nitric oxide synthase inhibitor, L-NAME (50mg/kgi.p.) while pretreatment of rats with NO-precursor l-Arginine (100mg/kg i.p.) produced potentiation of action of sub effective dose of DHEAS (5mg/kgs.c.). The DHEAS effects were stress specific as these behavioral and biochemical parameters were not much influenced in non-stressed rats. These observations suggest that pretreatment with DHEAS has a protective effect on restraint stress induced alteration of neurobehavioral changes and brain oxidative injury in rats and NO-dependent mechanisms may be involved in this effect.

Differential role of nitric oxide (NO) in acute and chronic stress induced neurobehavioral modulation and oxidative injury in rats

The present study evaluated the effects of acute and chronic restraint stress (RS 1 h or 6 h), and their modulation by nitrergic agents on neurobehavioral and oxidative stress markers in rats. Acute RS (1 h or 6 h) reduced open arm entries (OAE) and open arm time (OAT) in the elevated plus maze test - which were attenuated by the NO precursor, L-arginine but not influenced appreciably by the NO synthase inhibitor, L-NAME. These behavioral changes were associated with differential changes in brain NO metabolites (NOx) but consistently reduced GSH and raised MDA levels in comparison to the control group. Following RS 1 h x 10 the neurobehavioral suppression and changes in brain oxidative stress markers were less pronounced as compared to the acute RS (1 h) group indicating adaptation. L-arginine pretreatment facilitated this adaptation to chronic RS (1 h). Interestingly RS 6 h x 10, induced severe behavioral suppression and aggravation of MDA and NOx levels and L-NAME pretreatment tended to protect against these chronic RS induced aggravations. These results suggest that acute and chronic RS induces duration/intensity dependent neurobehavioral and oxidative injury which are under the differential regulatory control of NO.

Age related differences in stress-induced neurobehavioral responses in rats: modulation by antioxidants and nitrergic agents

The effect of restraint stress (RS) on neurobehavioral and brain oxidative/nitrosative stress markers and their modulation by antioxidants and nitrergic agents were evaluated in young (2 months) and old (16 months) male Wistar rats. Exposure to RS, induced anxiogenesis when tested in the elevated plus maze (EPM) and open field (OF) tests and such changes were greater in the old as compared to the young rats. These behavioral alterations were associated with enhanced levels of malondialdehyde (MDA) and reductions in glutathione (GSH), catalase (CAT) and nitric oxide metabolites (NOx) levels in brain homogenates-the effects being greater in intensity in the old as compared to the young animals. Pretreatment with antioxidants, alpha-tocopherol (25 and 50mg/kg) and N-acetylcysteine (100 and 200mg/kg) consistently reversed the RS-induced behavioral and biochemical alterations in both young and old rats. Similar attenuations of RS-induced changes were seen after pretreatment with NO precursor L-arginine (500 and 1000mg/kg) while the NO synthase inhibitor N-nitro L-arginine methyl ester (L-NAME) (50 and 100mg/kg) tended to aggravate the effects of RS in both age groups of rats. The results suggest that susceptibility to stress-induced neurobehavioral alterations may increase with age and interactions of reactive oxygen species (ROS) and nitric oxide in the central nervous system may exert a regulatory influence in such age dependent responses to stress.

Protective effects of dietary ginger (Zingiber officinales Rosc.) on lindane-induced oxidative stress in rats

The protective effect of dietary feeding of Zingiber officinales Rosc. (ginger) against lindane-induced oxidative stress was investigated in male albino rats. Oxidative stress was monitored by estimating the extent of lipid peroxidation, activities of the oxygen free radical (OFR) scavenging enzymes superoxide dismutase (SOD) and catalase (CAT) and the status of the glutathione redox cycle antioxidants. Lindane administration (30 mg/kg bw orally for 4 weeks) was associated with enhanced lipid peroxidation and compromised antioxidant defenses in rats fed a normal diet. Concomitant dietary feeding of ginger (1%w/w) significantly attenuated lindane-induced lipid peroxidation, accompanied by modulation of OFR scavenging enzymes as well as reduced glutathione (GSH) and the GSH dependent enzymes glutathione peroxidase (Gpx), glutathione reductase (GR) and glutathione-S-transferase (GST) in these rats. These findings suggest that a diet containing naturally occurring compounds is effective in exerting protective effects by modulating oxidative stress.

Modulation of stress-induced neurobehavioral changes and brain oxidative injury by nitric oxide (NO) mimetics in rats

The present study evaluated the effects of NO mimetics on stress-induced neurobehavioral changes and the possible involvement of ROS-RNS interactions in rats. Restraint stress (RS) suppressed both percent open arm entries and time spent in the open arms in the elevated plus maze (EPM) test. These RS-induced changes in EPM activity were attenuated by the NO mimetics, l-arginine, isosorbide dinitrate and molsidomine, in a differential manner. RS-exposed rats showed (a) increased lipid peroxidation (MDA) and (b) lowered reduced glutathione (GSH) and NO metabolites (NOx), in brain homogenates of these animals. Pretreatment with the NO mimetics also differentially influenced RS-induced changes in brain oxidative stress markers. The results suggest that NO may protect against stress-induced anxiogenic behavior and oxidative injury in the brain and highlight the significance of ROS-RNS interactions.

Comparative effect of topical application of lindane and permethrin on oxidative stress parameters in adult scabies patients

OBJECTIVES

The insecticides lindane and permethrin are commonly used for treatment of scabies. Animal studies have shown the presence of insecticide induced oxidative stress. Hence, this study was undertaken to assess and compare the effects of topical application of lindane and permethrin on oxidative stress parameters in scabies patients.

DESIGN AND METHODS

Patients were alternatively assigned to treatment by either 1% lindane lotion or 5% permethrin cream. Blood samples were collected before and 12-14 h after the application of the drugs and evaluated for oxidative stress parameters and compared with healthy controls.

RESULTS

Serum malondialdehyde (MDA) levels, erythrocyte superoxide dismutase (SOD) and catalase (CAT) activity were significantly increased while blood glutathione (GSH) levels were significantly decreased in the lindane group as compared to controls and the permethrin group. The permethrin treated group showed a non significant alteration in the oxidative stress parameters.

CONCLUSION

Topical application of lindane induced significant oxidative stress as compared to permethrin which appears to be a safer option for the treatment of scabies.

Current trends in nitric oxide research

Nitric oxide (NO), a molecule with multidimensional effects has generated exponential amount of research since its identification as a biological messenger almost two decades back. The recent trend in NO research is to explore newer dimensions in the cellular and molecular mechanisms of actions and interactions of NO with various biomolecules and their implications in various pathophysiological states. Advances in our knowledge of the mechanisms by which this pleiotropic molecule regulates the expression of eukaryotic genes has generated considerable excitement and is paving the way for development of novel NO based therapeutic strategies. However, it is still a challenge to understand fully the paradox of beneficial and damaging effects of this exciting molecule. This review will discuss the current trends of research in this area especially highlighting the new insights gained from recent experimental and clinical studies. New approaches to reduce or augment the availability of NO to benefit a wide range of clinical conditions and avenues for future research are also briefly discussed.

Possible involvement of free radicals in the differential neurobehavioral responses to stress in male and female rats

The effect of restraint stress (RS) on neurobehavioral and brain oxidative stress parameters, and their modulation by antioxidants were evaluated in male and cycling female rats. Exposure to RS suppressed both open arm entries and open arm time in the elevated plus maze and these changes were more marked in males than in females. Assay of brain homogenates revealed that the behavioral suppression was associated with similar differential increases in malondialdehye (MDA) and decreases in glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) levels in males and females. Pretreatment with alpha-tocopherol (25 and 50 mg/kg) and N-acetylcysteine (100 and 200 mg/kg), attenuated the stress induced alteration of behavioral and oxidative stress markers in a consistent manner in both male and female rats. These findings suggest that males may be more susceptible than females to stress induced neurobehavioral changes and free radicals may exert a regulatory influence in such gender dependent responses to stress.

Role of free radicals in stress-induced neurobehavioural changes in rats

Effect of restraint stress (RS) and its modulation by antioxidants were evaluated on elevated plus maze (EPM) and open field (OF) tests in rats. Restraint stress (RS for 1 hr) reduced the number of open arm entries, as also the time spent on open arms indicating enhanced anxiogenic response in the EPM test as compared to normal non RS group of rats. Pretreatment with ascorbic acid (100 and 200 mg/kg) and alpha-tocopherol (30 and 60 mg/kg) attenuated these RS-induced effects. In the OF test, RS-reduced (a) ambulations; and (b) rearings, whereas an increase was seen in (a) latency of entry and (b) number of fecal boluses. The RS-induced changes in OF parameters were reversed after pretreatment with the antioxidants, (ascorbic acid and alpha tocopherol). Biochemical data showed that RS enhanced MDA levels in both serum and brain, and these were attenuated after pretreatment with the antioxidants. The pharmacological and biochemical results indicate that free radicals might be involved in such stress-induced neurobehavioural effects.

Virological investigation of a hepatitis E epidemic in North India

INTRODUCTION

Hepatitis E virus (HEV) infection is of major public health concern in the developing countries, including the Indian subcontinent, due to epidemics of large proportions, increased morbidity and high mortality, especially in pregnant women. This study shows the findings of two different epidemics that occurred due to HEV.

METHODS

Blood samples were collected from 116 suspected HEV patients. Sera were separated and tested for hepatitis A virus HAV immunoglobulin M (IgM), hepatitis B virus surface antigen, hepatitis C virus (HCV) antibody and HEV IgM by Micro ELISA. 15 acute samples were subjected to reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of HEV ribonucleic acid (RNA).

RESULTS

Of the 116 blood samples collected, 68 (58.6 percent) were positive for HEV IgM antibodies. Mixed infections of HEV with HAV and HCV were detected in three (4.4 percent) and five (7.4 percent) cases, respectively. 15 HEV IgM-positive acute blood samples subjected to RT-PCR showed the presence of specific 343 bp amplified HEV ORF1 gene product in five cases. No untoward effects were observed in the five HEV-infected pregnant women during their follow-up.

CONCLUSION

This study confirms the HEV aetiology and highlights a major disease outbreak that occurred due to mixing of drinking water with sewerage.

Immunotoxicity of phosphamidon following subchronic exposure in albino rats

Effect of subchronic doses of phosphamidon exposure on humoral and cell mediated immune (CMI) responses were studied in male albino rats using SRBC, ovalbumin and KLH as antigens. Humoral immune responses were assessed by estimating antibody titre against antigen and splenic plaque forming cells (PFC) assay. CMI responses were studied by using leucocyte migration inhibition (LMI), macrophage migration inhibition (MMI) and delayed type hypersensitivity (DTH) response. Results obtained in the present study revealed marked suppression of humoral and CMI responses in a dose dependent pattern. Hence, suppression of immune responses by phosphamidon even at subchronic doses is clearly an important aspect for its safety evaluation.

Protective effect of melatonin against propoxur-induced oxidative stress and suppression of humoral immune response in rats

Effect of melatonin in attenuation of propoxur induced oxidative stress and suppression of humoral immune response was studied in rats. Oral administration of propoxur (10 mg/kg) increased lipid peroxidation in serum after 28 days treatment. Superoxide dismutase, catalase and glutathione were also altered following propoxur exposure. In addition propoxur exposure markedly suppressed humoral immune response as assessed by antibody titre and plaque forming cell assay. Simultaneous treatment with melatonin (5 mg/kg, ip) markedly attenuated the effect of propoxur on (a) lipid peroxidation, (b) oxidative stress parameters and (c) immunotoxicity. Results have been discussed in the light of possible immunopotentiating and antioxidant effects of melatonin to understand the influence of oxidative stress on propoxur induced immunomodulation.

Molecular heterogeneity among north Indian isolates of Group A Streptococcus

AIM

To monitor molecular heterogeneity among the clinical isolates of group A Streptococcus (GAS) from north India by Vir and emm typing.

METHODS AND RESULTS

GAS isolates, 31 from pharyngitis and nine from rheumatic fever (RF)/rheumatic heart disease (RHD) patients were differentiated into 16 Vir types (VT). These isolates were further discriminated into 23 emm types. Most of emm types were Vir type specific, except few (7.5%), which revealed different Vir types within same emm type. The most prevalent emm type found was emm 49 (15%) followed by 7.5% of emm 69, emm 71 and emm 75 which were different from emm type distribution reported from south India.

CONCLUSIONS

Analysis of data revealed 40% heterogeneity by Vir typing and 57.5% by emm typing among GAS isolates which is significant in view of small number of isolates studied. SIGNIFICANCE OF IMPACT OF THE STUDY: The molecular study for the first time demonstrates different emm types prevalent and circulating in northern region of India and such data may help in selection of types for vaccine development.

Rapid detection of Haemophilus influenzae by hel gene polymerase chain reaction

AIMS

To evaluate the efficiency of hel gene polymerase chain reaction (PCR) to detect Haemophilus influenzae in various clinical/non-clinical samples.

METHODS AND RESULTS

Seventy-four clinical samples (cerebrospinal fluid, blood, sputum, throat and nasal swabs) and throat swabs of 17 asymptomatic carriers were collected. Primers were used to amplify the hel gene of H. influenzae encoding P4 outer membrane protein directly from the processed samples. The samples were also examined by conventional culture methods and the results were compared with those of PCR. The culture methods showed positive results in 60 (65.9%) of 91 samples in contrast to 62 (68.12%) samples tested positive by PCR. None of the culture-positive samples were PCR-negative while two of the culture-negative samples were PCR-positive. The specificity of the products was confirmed by Southern hybridization and failure of various other organisms to amplify the hel gene product. The sensitivity of the PCR assay was found to be 50 pg of DNA.

CONCLUSIONS

These findings suggest that the hel gene PCR is a rapid, sensitive and a specific new method for direct identification of H. influenzae.

SIGNIFICANCE AND IMPACT OF THE STUDY

Thus, this PCR test can improve the detection rate of H. influenzae in suspected clinical samples as compared with that of conventional culture methods.

Dynamics of market correlations: taxonomy and portfolio analysis

The time dependence of the recently introduced minimum spanning tree description of correlations between stocks, called the "asset tree" has been studied in order to reflect the financial market taxonomy. The nodes of the tree are identified with stocks and the distance between them is a unique function of the corresponding element of the correlation matrix. By using the concept of a central vertex, chosen as the most strongly connected node of the tree, an important characteristic is defined by the mean occupation layer. During crashes, due to the strong global correlation in the market, the tree shrinks topologically, and this is shown by a low value of the mean occupation layer. The tree seems to have a scale-free structure where the scaling exponent of the degree distribution is different for "business as usual" and "crash" periods. The basic structure of the tree topology is very robust with respect to time. We also point out that the diversification aspect of portfolio optimization results in the fact that the assets of the classic Markowitz portfolio are always located on the outer leaves of the tree. Technical aspects such as the window size dependence of the investigated quantities are also discussed.

Outer-membrane-protein subtypes of Haemophilus influenzae isolates from North India

Haemophilus influenzae serotype b and non-typable isolates from blood, cerebrospinal fluid, sputum and throat swabs of patients and carriers in North India were analysed by outer-membrane protein (OMP) profiling. OMP analysis could differentiate the samples into 18 different subtypes. The non-typable isolates were more variable than the serotype b samples. OMP subtypes 1-6 were found only among the serotype b isolates and subtypes 7-18 among the non-typable isolates, while subtypes 2 and 8 were exhibited by both. The OMP profiles of isolates from blood, cerebrospinal fluid and sputum are in complete agreement with their ribotypes and RAPD fingerprints. The present study demonstrates for the first time the subtyping of Indian H. influenzae isolates by an easy and less-expensive method that is applicable to developing countries like India.

Expression and purification of E2/NS1 protein of hepatitis C virus and detection of anti-E2/NS1 antibodies in chronic liver disease patients

Glycoproteins on the surface of viral particles present the main target of neutralizing antibodies. The structural proteins of most Flaviviruses are known to elicit neutralizing antibodies and, thus, to help in both the natural resolution of the infection and the protection from challenge with homologous hepatitis C virus (HCV). Because such antigens are associated with the viral clearance in both humans and chimpanzees, we aimed to express the E2/NS1 protein of HCV and to study the role of anti-E2/NS1 antibodies in the natural resolution of HCV infection. The prevalence of anti-E2/NS1 antibodies to recombinant E2/NS1 protein was seen by Western blot in chronic liver disease patients (15 chronic hepatitis and 12 cirrhotic patients), who were positive for anti-HCV and negative for HBV infection. The study also included 2 negative controls (positive for HBV infection and negative for anti-HCV antibodies) and 2 healthy controls (negative for both HBV and HCV infection). Anti-E2/NS1 was present in 20% of the chronic hepatitis and 16% of the cirrhosis patients. None of the controls were positive for anti-E2/NS1 antibodies. Serum samples positive for anti-E2/NS1 antibodies were also positive for HCV RNA by RT/PCR. Accordingly, the presence of anti-E2/NS1 may have very little or no role in the natural resolution of HCV infection.

Association of pyrogenic exotoxin genes with pharyngitis and rheumatic fever/rheumatic heart disease among Indian isolates of Streptococcus pyogenes

AIM

To monitor the presence of various pyrogenic exotoxin genes in strains of Streptococcus pyogenes isolated in India.

METHODS & RESULTS

Isolates recovered from pharyngitis (52) and rheumatic fever (RF)/ rheumatic heart disease (RHD) (8) patients were analysed for the presence of toxin genes, speA, speB and speF, by PCR. The specificity of the products was confirmed by restriction enzyme digestion and Southern hybridization. Among the 60 isolates studied, the incidence of speA, speB and speF were 5(8.3%), 56(93.3%) and 53(88.3%), respectively. The expression of these genes was established in representative isolates by RT-PCR.

CONCLUSIONS

Comparative analysis of frequency of the speA, speB and speF genes, among pharyngitis and RF/RHD associated isolates, showed higher incidence in RF/RHD (25%, 100%,100%) as compared to pharyngitis patients (5.8%, 92.3%, 86.5%), respectively. SIGNIFICANCE OF STUDY: The presence of the speA gene, which is usually associated with scarlet fever or toxic shock-like syndrome, within few Indian isolates may be indicative of new virulent strains circulating within the Indian community. High distribution of toxin genes among RF/RHD compared to pharyngitis isolates indicate their possible role in increased virulence.

Identification of human hepatocyte protein(s), which binds specifically to the recombinant envelope-2/non-structural-1 protein of hepatitis C virus

Hepatitis C virus (HCV), which is the major pathogen responsible for human chronic liver disease, has special tropism for hepatocytes. Although, low-density lipoprotein receptor, CD81 and negatively charged glycosaminoglycans have been proposed as candidate receptors for HCV, no confirmed receptor(s) on the hepatocytes have been identified to date. It is also suggested that additional, yet unidentified, cellular proteins may be involved in the host-viral interaction. Therefore, this study was conducted with the main aim to identify hepatocyte protein(s) that may have affinity for the HCV structural protein, envelope-2/non-structural-1 (E2/NS1) protein. For the binding studies, hepatocytes were isolated from fresh normal human liver tissues. The hepatocyte proteins on the nitrocellulose paper were reacted with recombinant E2/NS1 protein and anti-E2 (rabbit). In another approach, to rule out the possibility of binding of rec-E2/NS1 with the hepatocyte cytoplasmic proteins, hepatocyte plasma membrane proteins were passed through CNBr-activated and recombinant E2/NS1 bound sepharose-4B column. The recombinant E2/NS1 binding hepatocyte plasma membrane protein(s) were eluted and were then analyzed. Altogether, our data suggest that E2/NS1 protein of HCV binds to two hepatocyte proteins of molecular weights 25-28 kDa and 59-60 kDa. These results indicate the possible role of the above proteins (25-28 kDa and 59-60 kDa) in the viral binding to the hepatocytes.

Subtype distribution of Haemophilus influenzae isolates from north India

A total of 120 Haemophilus influenzae isolates from blood, cerebrospinal fluid, sputum and throat swabs of patients and carriers in North India was characterised by biotyping, ribotyping and random amplification of polymorphic DNA (RAPD)-PCR. Of these, 77 isolates (64%) were serotype b; the other 43 (36%) were non-typable. Biotype I was the most predominant among the typable strains and biotype II among the non-typable strains. Ribotyping with restriction endonucleases HaeIII and EcoRI differentiated the isolates into three and six ribotypes, respectively. However, RAPD fingerprints generated by the application of arbitrary primers AP1 and AP2 provided a higher level of discrimination. RAPD typing revealed distinct polymorphism among the serologically typable isolates. This study is the first report that stratifies the subtypes of H. influenzae strains from India by molecular techniques.

Intracameral amphotericin B: initial experience in severe keratomycosis

PURPOSE

Fungal keratitis is a significant cause of ocular morbidity in India. The most commonly implicated fungi are Aspergillus spp. Patients often present with hypopyon, which usually contains fungal elements. The treatment is difficult owing to poor intraocular penetration of most available antifungal agents. This study evaluated the results of intracameral injection of amphotericin B in natamycin resistant cases of severe keratomycosis.

METHODS

Three patients of culture proven Aspergillus flavus corneal ulcer with hypopyon not responding to topical natamycin 5%, amphotericin B 0.15%, and oral itraconazole were administered intracameral amphotericin B. The first case received 7.5 microg in 0.1 mL followed by two subsequent injections of 10 microg in 0.1 mL each, the second case received two injections of 10 microg in 0.1 mL, and the third patient received a single dose of 10 microg in 0.1 mL. Culture of the aqueous sample also grew A. flavus in all three cases.

RESULTS

All three cases responded favorably, with the ulcer and hypopyon clearing completely. There was no clinical evidence of corneal or lenticular toxicity in any patient.

CONCLUSIONS

Intracameral amphotericin B may be a useful modality in the treatment of severe keratomycosis not responding to topical natamycin. It ensures adequate drug delivery into the anterior chamber and may be especially useful to avoid surgical intervention in the acute stage of the disease.

Characterization of a Galactose Specific Adhesin of Enteroaggregative Escherichia coli

A fimbrial adhesin was identified from an enteroaggregative Escherichia coli strain. The adhesin was purified to 740-fold by sequential chromatography on an affinity matrix and gel filtration column in the FPLC system. The homogeneity of the purified protein was established by analytical isoelectrofocussing (pI 7.25). The native adhesin appeared as a high-molecular-weight aggregative protein as revealed by gel filtration chromatography on Superose 12HR10/30 column. However, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis the molecular weight of the adhesin was found to be 18 kDa and this was further confirmed by gel filtration chromatography on Superose 6HR 10/30 column presence of 6 M guanidine hydrochloride. The N-terminal 15-amino-acid sequence of the adhesin did not show homology with any of the previously reported fimbrial adhesins. The purified adhesin showed adhesion to human erythrocytes in the presence of Ca(2+) (5 mM). The optimum temperature and pH for the hemadhesion activity was found to be 25 degrees C and 6.5, respectively. The inhibition study clearly suggested that the binding site of the adhesin could recognize galactose as the specific sugar. The fluorescence of 4-methylumbelliferyl-alpha-D-galactopyranoside was quenched on binding to the adhesin and maximum reversal of fluorescence quenching was observed by competitive substitution titration with raffinose. The adhesin was found to contain one binding site per monomer for its specific sugar residue. The association constant and the free energy of binding were obtained as 3.98 x 10(5) M(-1) and -31.97 kJ/mol, respectively. The adherence of the bacteria to HEp-2 monolayer was inhibited in presence of galactose and this was further supported by a significant reduction in the bacterial adherence to the HEp-2 cells, pretreated with beta-D-galactosidase.

Entamoeba histolytica: rapid detection of indian isolates by cysteine proteinase gene-specific polymerase chain reaction

Amoebiasis, caused by Entamoeba histolytica, is still one of the major problems for developing countries like India. Early detection of the parasite is a must for its prevention and control. In this study, PCR analysis of the cysteine proteinase gene from clinical isolates of symptomatic intestinal and amoebic liver abscess (ALA) cases has been compared with the stool microscopy, serology, and ultrasonography methods. The clinical isolates negative for E. histolytica by stool microscopy demonstrated the presence of the cysteine proteinase gene by PCR amplification. Also the gene copy number was increased in ALA samples compared with intestinal cases. Hence an accurate, early, and easier detection was possible by cysteine proteinase gene amplification directly from the clinical samples.