Anomalous pressure dependence of the electronic transport and anisotropy in SrIrO3films

Iridate oxides display exotic physical properties that arise from the interplay between a large spin-orbit coupling and electron correlations. Here, we present a comprehensive study of the effects of hydrostatic pressure on the electronic transport properties of SrIrO3(SIO), a system that has recently attracted a lot of attention as potential correlated Dirac semimetal. Our investigations on untwinned thin films of SIO reveal that the electrical resistivity of this material is intrinsically anisotropic and controlled by the orthorhombic distortion of the perovskite unit cell. These effects provide another evidence for the strong coupling between the electronic and lattice degrees of freedom in this class of compounds. Upon increasing pressure, a systematic increase of the transport anisotropies is observed. The anomalous pressure-induced changes of the resistivity cannot be accounted for by the pressure dependence of the density of the electron charge carriers, as inferred from Hall effect measurements. Moreover, pressure-induced rotations of the IrO6octahedra likely occur within the distorted perovskite unit cell and affect electron mobility of this system.

Public health crisis of road traffic accidents in India: Risk factor assessment and recommendations on prevention on the behalf of the Academy of Family Physicians of India

Roads are considered a sign of development bringing colossal benefits to community as socioeconomic and logistic facilitator. Yet, growth of road network has brought road crashes leading to civic pain from premature deaths of productive age group. In 2017, 16 citizens were killed and 53 injured every hour on Indian roads as per officially reported data, while a fair number go unreported. This is unacceptably high when compared with international standards. Risk correlates of road traffic injuries (RTIs) need to be redefined so as to form a continuum with other confounding factors that impact to take lives on road. Risk factors impacting RTIs vary from human components to the roles and responsibilities of healthcare stakeholders. We should have made roads safer for all citizens because a large percentage of population – children, pedestrians, cyclists, motorcyclists, and the elderly – are most vulnerable. A taskforce was set up by the Academy of Family Physicians of India to scientifically analyze the literature available to assess risks and put forward appropriate recommendations.

Immunoprotective responses of T helper type 1 stimulatory protein-S-adenosyl-L-homocysteine hydrolase against experimental visceral leishmaniasis

It is well known that a patient in clinical remission of visceral leishmaniasis (VL) remains immune to reinfection, which provides a rationale for the feasibility of a vaccine against this deadly disease. In earlier studies, observation of significant cellular responses in treated Leishmania patients as well as in hamsters against leishmanial antigens from different fractions led to its further proteomic characterization, wherein S-adenosyl-L-homocysteine hydrolase (AdoHcy) was identified as a helper type 1 (Th1) stimulatory protein. The present study includes immunological characterization of this protein, its cellular responses [lymphoproliferation, nitric oxide (NO) production and cytokine responses] in treated Leishmania-infected hamsters and patients as well as prophylactic efficacy against Leishmania challenge in hamsters and the immune responses generated thereof. Significantly higher cellular responses were noticed against recombinant L. donovani S-adenosyl-L-homocysteine hydrolase (rLdAdoHcy) compared to soluble L. donovani antigen in treated samples. Moreover, stimulation of peripheral blood mononuclear cells with rLdAdoHcy up-regulated the levels of interferon (IFN)-γ, interleukin (IL)-12 and down-regulated IL-10. Furthermore, vaccination with rLdAdoHcy generated perceptible delayed-type hypersensitivity response and exerted considerably good prophylactic efficacy (∼70% inhibition) against L. donovani challenge. The efficacy was confirmed by the increased expression levels of inducible NO synthase and Th1-type cytokines, IFN-γ and IL-12 and down-regulation of IL-4, IL-10 and transforming growth factor (TGF)-β. The results indicate the potentiality of rLdAdoHcy protein as a suitable vaccine candidate against VL.

Single staged complete length excision of the holocord ependymoma: Team work

The authors present a case of a 15-year-old male patient who presented with gradually progressive quadriparesis for 3 years. Magnetic resonance imaging of the spine was suggestive of heterogeneously enhancing mass lesion extending from cervicomedullary junction to conus. This holocord spinal tumor was excised in a single stage with standard microsurgical technique. In immediate postoperative period, the patient had deterioration in power in both lower limbs which improved in follow-up at 6 months. Histopathology of the tumor was suggestive of ependymoma. Holocord ependymoma is a rare entity; until now, only six cases have been described in the literature. To the author's best knowledge, this is only the second case of holocord ependymoma excised in a single stage.

Remote cerebellar hemorrhage: Report of 2 cases and review of literature

Remote cerebellar hemorrhage (RCH) is an extremely rare and potentially devastating complication of supratentorial and spinal surgeries. While there are numerous postulates explaining the patho-physiology behind this phenomenon, including the most popular CSF over drainage theory, the exact cause for the same is still largely unknown. In this report, we present 2 cases of remote cerebellar hemorrhage encountered following 2 different surgical procedures. One patient had preceding pterional craniotomy for ruptured anterior communicating artery aneurysm while the other one developed RCH after placement of EVD. Both of them had history of poorly controlled hypertension, contrary to most reports where hypertension has not been found to be commonly associated with it. Moreover, while most cases have been reported to occur following supratentorial craniotomies and spinal surgeries, one of our patients developed the same after placement of the EVD, which, to the best of our knowledge, has not been reported earlier.

Enhanced mechanical strength and biocompatibility of electrospun polycaprolactone-gelatin scaffold with surface deposited nano-hydroxyapatite

In this study for the first time, we compared physico-chemical and biological properties of polycaprolactone-gelatin-hydroxyapatite scaffolds of two types: one in which the nano-hydroxyapatite (n-HA) was deposited on the surface of electrospun polycaprolactone-gelatin (PCG) fibers via alternate soaking process (PCG-HAAS) and other in which hydroxyapatite (HA) powders were blended in electrospinning solution of PCG (PCG-HAB). The microstructure of fibers was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which showed n-HA particles on the surface of the PCG-HAAS scaffold and embedded HA particles in the interior of the PCG-HAB fibers. PCG-HAAS fibers exhibited the better Young's moduli and tensile strength as compared to PCG-HAB fibers. Biological properties such as cell proliferation, cell attachment and alkaline phosphatase activity (ALP) were determined by growing human osteosarcoma cells (MG-63) over the scaffolds. Cell proliferation and confocal results clearly indicated that the presence of hydroxyapatite on the surface of the PCG-HAAS scaffold promoted better cellular adhesion and proliferation as compared to PCG-HAB scaffold. ALP activity was also observed better in alternate soaked PCG scaffold as compared to PCG-HAB scaffold. Mechanical strength and biological properties clearly demonstrate that surface deposited HA scaffold prepared by alternate soaking method may find application in bone tissue engineering.

Analysis of finit in urine sample using thin layer chromatography

Finit is a common insecticide generally used to control a variety of insects in homes. Routinely it is analysed by Gas Liquid Chromatography (GLC) and High Performance Liquid Chromatography (HPLC). An attempt has been made to develop a new method for analysis of finit in urine samples using Thin Layer Chromatography (TLC) technique which is inexpensive, accurate and non-destructive. Finit was extracted from urine using solvent extraction methods and then identified on the TLC plates. For detection on developed plates, palladium chloride, silver nitrate, iodine vapour and bromophenol blue were used which successfully increased the sensitivity without dispensing with the simplicity of the method. The method developed is simple, inexpensive, accurate and non-destructive that allows for sensitive and reproducible analysis of finit.

Disseminated superficial and warty type of porokeratosis: a rare coexistence

A 60-year-old male presented with hyperpigmented annular plaques with raised keratotic wall and central groove along with warty plaque involving the trunk and the extremities, respectively. A provisional diagnosis of porokeratosis was made which was confirmed histopathologically. Herein, we report a case of rare coexistence of disseminated superficial and warty porokeratosis.

Pattern of poisoning cases in a hospital in a Terai district of central Nepal

Poisoning is a major global health problem and is one of the major causes of hospitalization through emergency. The objective of this study is to evaluate the characteristics of poisoning cases admitted to emergency department over a one year period. A hospital based study was carried out in the emergency department, Mahendra Adarsha Chikitsalaya, Chitwan analyzing the data of the poisoning cases attended for one year duration by searching all the medical records. A total of 921 poisoning cases presented to emergency department in the year 2007. The female to male ratio was 1.17:1. Most of poisoning occurred in the age group 15-24 years. Snake bite was the commonest form of poisoning amongst all cases. By occupation, 46.0% cases were in farmers. Accidental poisoning prevailed over intentional poisoning. Seasonal trend revealed maximum cases being in summer (42.4%). Poisoning shows seasonal trend and hence proper intervention is required in community level.

A case of leprosy with multiple cranial neuropathy mimicking Melkerson Rosenthal syndrome

Involvement of cranial nerves is not uncommon in leprosy with trigeminal and facial nerves being commonly affected. Other cranial nerves can also be involved especially in longstanding cases of leprosy towards the lepromatous pole. Herein, we report a case of leprosy with multiple cranial neuropathy mimicking Melkerson Rosenthal syndrome.

Prevalence of pharmacotherapy in the department of paediatric dentistry

BACKGROUND

Pharmacotherapy plays important role in the management of paediatric dental patients in the department of paediatric dentistry. Many children at their early age suffer from different kinds of dental conditions such as acute and chronic irreversible pulpitis, acute and chronic alveolar abscesses, dentoalveolar and vestibular abscesses, etc along with physiological tooth movement that requires professional help for dental treatment. Treatment of such conditions most frequently requires pharmacotherapy as an either adjunct to dental therapeutic procedure or as a monotherapy.

OBJECTIVE

To assess the prescribing patterns vis-a-vis generic or trade name, generic class, dosage form, route, frequency, duration, number of drugs per patient, cost and indication of drug therapy, patterns of dental treatment and Frankl's behavioral rating.

MATERIALS AND METHODS

Prescriptions of 200 paediatric dental patients undergoing dental treatment in the department of paediatric dentistry were analyzed prospectively for a period of six months in a dental teaching hospital.

RESULTS

133 (56.5%) patients were males and 87 (43.5%) females and age group 6-10 years was the most frequent group (70%, P = 0.0000000) and all the patients received pharmacotherapy. Total numbers of 357 drugs were prescribed. Out of them, 212 (59.4%, P = 0.0000008) were analgesic agents, 133 (37.3%) antimicrobial agents (AMAs) and 12 (3.3%) other drugs. Extended spectrum Penicillins were the most commonly prescribed (90.2%) AMA followed by Metronidazole (9.8%). 247 drugs (69.2%, P = 0.0000000) were prescribed by trade names. 60% (P = 0.0000002) drugs were prescribed in the form of tablet or capsule followed by syrup 37% and administered entirely through oral route. Percentage of patients receiving three drugs, two drugs and one drug was 13.5%, 56.5% (P = 0.0000000) and 30% respectively and one patient received on average 1.78 medicines. 133 patients (56.5%, P = 0.0000000) received both AMA and analgesic agent. Minimum to maximum number of days for pharmacotherapy were 2 to 15 and highest frequency was up to four times a day. Cost of medicines was in the range of 10-150 Nepalese Rupees. Chronic irreversible pulpitis was the commonest diagnosis (28%) and extraction (92.5%) was the commonest dental procedure. Frankl's behaviour rating showed that 78.5% (P = 0.0000000) patients had positive attitude towards the dental procedures.

CONCLUSION

Findings of the study suggest that pharmacotherapy is the mainstay in therapy to treat the paediatric dental patients along with dental procedures either to control the dental pain or odontogenic infection. Age group 6-10 years, chronic irreversible pulpitis and dental extraction are the commonest age group, diagnosis and dental procedure respectively in the department of paediatric dentistry. Analgesic (non-steroidal anti-inflammatory drugs- Nimesulide, Ibuprofen and Paracetamol) and Amoxicillin are the most frequently prescribed drugs mostly in the solid dosage forms in trade names via oral route. Duration of pharmacotherapy ranges from 2 to 15 days with highest frequency being up to 4 times a day. Majority of the patients are manageable without any behavioural modification technique- physical or pharmacological.

Substance Use among Medical Students in Kathmandu Valley

Introduction: Substance use including tobacco and alcohol is the most important cause of preventable morbidity, disability, and premature mortality. The study aims to specify the prevalence and the pattern of use of different substance. Methods: A cross sectional study was performed amongst first year and final year students in four medical colleges in Kathmandu using self administered anonymous questionnaire.Data collectedfrom 446 students were analyzed. Results: Prevalence of substance use was found to be 60.3% among the medical students. Alcohol (57.6%) was the substance most prevalently used followed by tobacco (27.58%) and cannabis (12.8%). Mean age of first exposure was 17.94 (Confidence interval: 17.91-17.97). There was significant difference in the useof tobacco and cannabis amongst final year students than first year students. Male and female differed significantly in use of every substance except for benzodiazepine. Medical college, college and school were place of first exposure in 17.26%, 15.92% and 13.23% of the cases respectively. Family history was associated with substance use in medical students and was statistically significant (P<0.0001).Experimentation was the major reason for the use of most of the substances. Conclusions: Substance use is prevalent in male medical students of both first and final year. Hence steps should be initiated early in school, college and medical college to prevent substance use. Keywords: alcohol, medical students, substance use, tobacco.

Substance use among medical students in Kathmandu valley

INTRODUCTION

Substance use including tobacco and alcohol is the most important cause of preventable morbidity, disability, and premature mortality. The study aims to specify the prevalence and the pattern of use of different substance.

METHODS

A cross sectional study was performed amongst first year and final year students in four medical colleges in Kathmandu using self administered anonymous questionnaire.Data collectedfrom 446 students were analyzed.

RESULTS

Prevalence of substance use was found to be 60.3% among the medical students. Alcohol (57.6%) was the substance most prevalently used followed by tobacco (27.58%) and cannabis (12.8%). Mean age of first exposure was 17.94 (Confidence interval: 17.91-17.97). There was significant difference in the useof tobacco and cannabis amongst final year students than first year students. Male and female differed significantly in use of every substance except for benzodiazepine. Medical college, college and school were place of first exposure in 17.26%, 15.92% and 13.23% of the cases respectively. Family history was associated with substance use in medical students and was statistically significant (P<0.0001).Experimentation was the major reason for the use of most of the substances.

CONCLUSIONS

Substance use is prevalent in male medical students of both first and final year. Hence steps should be initiated early in school, college and medical college to prevent substance use.

Bilateral lagophthalmos in leprosy: is it a rare phenomenon?

Lagophthalmos is one of the well known complications of leprosy due to involvement of the facial nerve. Herein, we report three cases of bilateral lagophthalmos due to leprosy which presented to us within a span of just three months. In all these cases, lagophthalmos was not the presenting complaint and it was detected by the treating doctor during examination. This report is being presented to highlight the importance of cranial nerve examination in all cases of leprosy as at times early changes of lagophthalmos may go unnoticed by the patient.

INrf2 (Keap1) targets Bcl-2 degradation and controls cellular apoptosis

Cytosolic inhibitor of Nrf2 (INrf2) is an adaptor protein that mediates ubiquitination/degradation of NF-E2-related factor 2 (Nrf2), a master regulator of cytoprotective gene expression. In this paper, we demonstrate that INrf2 degrades endogenous antiapoptotic B-cell CLL/lymphoma 2 (Bcl-2) protein and controls cellular apoptosis. The DGR domain of INrf2 interacts with the BH2 domain of Bcl-2 and facilitates INrf2:Cul3-Rbx1-mediated ubiquitination of Bcl-2 by the conjugation of ubiquitin molecules to lysine17 of Bcl-2. Further studies showed that INrf2 enhanced etoposide-mediated accumulation of Bax, increased release of cytochrome c from mitochondria, activated caspase-3/7, and enhanced DNA fragmentation and apoptosis. Antioxidants antagonized Bcl-2:INrf2 interaction, led to the release and stabilization of Bcl-2, increased Bcl-2:Bax heterodimers and reduced apoptosis. Moreover, dysfunctional/mutant INrf2 in human lung cancer cells failed to degrade Bcl-2, resulting in decreased etoposide and UV/γ radiation-mediated DNA fragmentation. These data provide the first evidence of INrf2 control of Bcl-2 and apoptotic cell death, with implications in antioxidant protection, survival of cancer cells containing dysfunctional INrf2, and drug resistance.

Monocular visual loss due to herniation of gyrus rectus: A case report with review of literature

The authors present an unusual case of a polar mass in the frontal lobe of the brain, causing acute monocular visual loss in a 50-year-old woman with history of breast carcinoma treated with surgery, radiation and chemotherapy. Neuroimaging demonstrated herniation of the gyrus rectus into the suprasellar cistern resulting in compression of the anterior visual pathway.

Anxiogenic potential of ciprofloxacin and norfloxacin in rats

INTRODUCTION

The possible anxiogenic effects of fluoroquinolones, namely ciprofloxacin and norfloxacin, were investigated in adult Charles Foster albino rats of either sex, weighing 150-200 g.

METHODS

The drugs were given orally, in doses of 50 mg/kg for five consecutive days and the experiments were performed on the fifth day. The tests included open-field exploratory behaviour, elevated plus maze and elevated zero maze, social interaction and novelty-suppressed feeding latency behaviour.

RESULTS

The results indicate that ciprofloxacin- and norfloxacin-treated rats showed anxious behaviour in comparison to control rats in all the parameters studied. However, ciprofloxacin- and norfloxacin-treated rats did not differ significantly from each other in various behavioural parameters.

CONCLUSION

The present experimental findings substantiate the clinically observed anxiogenic potential of ciprofloxacin and norfloxacin.

Chiari I malformation associated with atlanto-axial dislocation: focussing on the anterior cervico-medullary compression

BACKGROUND

Chiari I malformation with atlantoaxial dislocation may cause both posterior and anterior cervicomedullary compression. We studied the clinicoradiological features and surgical outcome in patients having Chiari I malformation with atlantoaxial dislocation.

METHOD

Thirty-nine patients with Chiari I malformation with atlanto-axial dislocation underwent preoperative and follow-up neurological status assessment. In Chiari I malformation with reducible atlanto-axial dislocation (n = 11), a direct posterior stabilization was done. In Chiari I malformation with irreducible atlanto-axial dislocation (n = 28), a single stage transoral decompression with posterior stabilization and/or posterior decompression and duraplasty were done in 18 patients. In 10 patients, only posterior decompression and/or posterior stabilization was performed. Seven among the latter patients subsequently deteriorated and required transoral decompression. Comparison of mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization versus the posterior procedure alone was done using T-test and proportional significance also calculated.

FINDINGS

Patients with Chiari I malformation with atlanto-axial dislocation have a high incidence of long tract signs and sphincteric disturbances with a decrease in the mean foramen magnum diameter. The mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization were significantly better than those patients who underwent the posterior procedure alone. The latter patients also showed significant clinical improvement following transoral decompression. In the presence of Chiari I malformation with reducible atlanto-axial dislocation, reduction and stabilization of atlanto-axial dislocation resulted in neurological improvement. The follow up neurological status scores of these patients improved after surgical intervention even in the presence of poor preoperative grades.

CONCLUSIONS

Patients with Chiari I malformation should be investigated for the presence of atlanto-axial dislocation. In case atlantoaxial dislocation coexists, priority must be given to relieving anterior cervicomedullary compression.

Spinal ossifying lipoma

A case of ossifying spinal lipoma is reported. The patient presented with a large swelling over the lumbar region with a dermal sinus in the centre. Imaging revealed an intradural lipoma connected with a large subcutaneous lipoma in which there was a prominent island of bone. The lipoma was excised and there were no postoperative neurological deficits. To the best of our knowledge, this is the first report of a spinal ossifying lipoma associated with a dermal sinus.

Primary plasma cell granuloma of petrous bone

Plasma cell granulomas are rare intracranial lesions that can mimic a variety of intracranial tumours. As they are usually benign lesions, their identification assumes importance. We report a case of plasma cell granuloma in a 52-year-old man presenting with features of left sided V, VII and bilateral VIII nerve involvement who underwent subtotal excision of the lesion. The relevant literature is reviewed.

Foramen magnum tumors: a series of 30 cases

BACKGROUND AND AIMS

Foramen magnum tumors, especially those located ventrally, are surgically challenging. We studied clinical and surgical details of extramedullary tumors located in the region of the foramen magnum.

MATERIAL AND METHODS

A series of 30 cases of extramedullary tumors at the foramen magnum, operated over a period of 8 years is presented.

RESULTS

There were 10 neurofibromas, 8 meningiomas, 6 chordomas, 2 tuberculomas and 4 miscellaneous tumors. The clinical profile consisted of sensory symptoms in all the patients, quadriparesis in 24, lower cranial nerve affection in 8 and sphincter disturbances in 6 patients. The surgical approaches consisted of an extreme lateral approach in 10, a posterior or posterolateral approach in 18 and a per-oral route in 2 cases. Total excision of the tumor was performed in 24 and a subtotal excision of the tumor was done in 6 cases. Two patients died, one due to meningitis and the other due to chest infection. Eight other patients had complications like CSF leak, meningitis, pseudomeningocele, laryngeal edema, and transient worsening of neurological deficits.

CONCLUSIONS

Foramen magnum tumors have long been regarded as difficult lesions both in terms of diagnosis and management. However, with the availability of MR imaging, newer surgical techniques and skull basal exposures, the excision of these lesions is becoming easier and safer.

Lymphocutaneous sporotrichosis treated with three different modalities

Three cases of lymphocutaneous sporotrichosis were treated with three different modalities and oral saturated solution of potassium iodide was found to be best modality.

Painful bruising syndrome

Painful bruising syndrome is a distinctive but rare clinical entity. A case of this condition in a psychiatrically normal teenage girl is reported.

Does pentoxifylline find a place in the armementarium of leprologists in type II reaction?

Alternative therapeutic interventions in Type II lepra reaction are being considered following serious problems associated with the use of steroids and thalidomide. Pentoxifylline (PTX) has been used in Type II reaction with varying degrees of success. The results of a study on the use of this drug in a dose of 1200 mg per day for a period of 2 months in patients with ENL reaction are discussed. Five patients, one of whom was HIV positive--all with severe Type II reaction, were regularly evaluated for regression of inflammatory symptoms and clinical involution of ENL lesions while on PTX therapy and thereafter. It was found that PTX led to a total elimination of systemic symptoms within a week. ENL lesions regressed in two weeks. However, in one patient, lesions recurred after one month of therapy. It appears that PTX is well tolerated and could be used as an additional drug in the armamentarium of leprologists in the management of Type II reaction, especially in HIV co-infection, where long-term steroids are contraindicated. However, further studies to compare the effects of PTX with currently, widely used drugs for the treatment of ENL reaction are necessary.

Ecologic perspective of dermatologic problems in North Eastern India

In the nations of the developing world, the incidence of skin diseases is especially affected by geography. Epidemiological studies of skin diseases are important in the study of disease pattern, changes in disease pattern and for planning dermatology service and research for a country. This report records the pattern of skin diseases encountered in the North-East region of India. The incidence of non-infectious dermatoses was slightly higher than that of infectious dermatoses in this part of the country.

Acquired (digital) fibrokeratoma

Acquired digital fibrokeratoma is a rarely reported disorder, especially in the Indian literature. We report our findings on one such case, occurring at an unusual site.

Changing trends in sexually transmitted diseases in North Eastern India

A retrospective data analysis was carried out to find the trends in frequency and distribution of different STDs in North Eastern (NE) India during 1995-1999. The commonest STD was chancroid (25.7%) followed by condylomata acuminata (CA), nongonococcal urethritis (NGU), lymphogranuloma venereum (LGV), syphilis, gonorrhoea (GONO), herpes genitalis (HG), mixed infection (MI) and balanoposthitis (BP). Interestingly no case of donovanosis (Dono) was seen. HIV infection accounted for 9.62% of the total STD patients. A comparison of the present data with that reported a decade back (1986-1990) revealed a sharp decline in the incidence of syphilis, chancroid, GONO, whereas a conspicuous upward trend in CA and NGU. Factors responsible for these variations are analysed briefly.

Effect of environmental deprivation on anxiety in rats

Environmental deprivation (ED) induced a significant increase in open-field ambulation, rears, self-groomings, faecal pellets and decrease in activity in centre in Charles Foster albino rats of 30, 45 and 60 days age groups. In elevated plus maze, significant attenuation of open arm time/entries and augmentation of enclosed arm time/entries were noted in ED rats of all the three age groups. Similarly ED rats also showed significant decrease in time spent on open arms, entries, head dips and stretched attend postures in comparison to age matched rats reared under normal environmental conditions. The results indicate that imposition of environmental deprivation in rats' life consistently resulted in significant anxiogenic behaviour on all the tests. However, the anxiogenic effect of ED was less marked when it was imposed at 60th day of life in rats.

NAD(P)H:quinone oxidoreductase 1 deficiency and increased susceptibility to 7,12-dimethylbenz[a]-anthracene-induced carcinogenesis in mouse skin

BACKGROUND

The phase II enzyme NAD(P)H :quinone oxidoreductase 1 (NQO1) catalyzes quinone detoxification, protecting cells from redox cycling, oxidative stress, mutagenicity, and cytotoxicity induced by quinones and its precursors. We have used NQO1(-/-) C57BL/6 mice to show that NQO1 protects them from skin cancer induced by the polycyclic aromatic hydrocarbon benzo[a]pyrene. Herein, we used NQO1(-/-) mice to investigate whether NQO1 also protects them against 7,12-dimethylbenz[a]anthracene (DMBA), where methyl substituents diminish primary quinone formation.

METHODS

Dorsal skin of NQO1(-/-) or wild-type C57BL/6 mice was shaved. When tested as a complete carcinogen, DMBA (500 or 750 microg in 100 microL of acetone) alone was applied to the shaved area. When tested as a tumor initiator, DMBA (200 or 400 nmol in 100 microL of acetone) was applied to the shaved area; 1 week later, twice-weekly applications of phorbol 12-myristate 13-acetate (PMA)-10 microg dissolved in 200 microL of acetone-to the same area began and were continued for 20 weeks. Tumor development was monitored in all mice (12-15 per group). All statistical tests were two-sided.

RESULTS

When DMBA (750 microg) was tested as a complete carcinogen, about 50% of the DMBA-treated NQO1(-/-) mice but no DMBA-treated wild-type mouse developed skin tumors. When DMBA (both concentrations) was used as a tumor initiator, NQO1(-/-) mice developed larger tumors at a greater frequency than their wild-type littermates. Twenty-three weeks after the first PMA treatment in the tumor initiator test, all 30 NQO1(-/-) mice given 400 nmol of DMBA had developed skin tumors, compared with 33% (10 of 30) of treated wild-type mice (P<.001).

CONCLUSIONS

NQO1(-/-) mice are more susceptible to DMBA-induced skin cancer than are their wild-type littermates, suggesting that NQO1 may protect cells from DMBA carcinogenesis.

Functional characterization and role of INrf2 in antioxidant response element-mediated expression and antioxidant induction of NAD(P)H:quinone oxidoreductase1 gene

Antioxidant response element (ARE) and nuclear transcription factor Nrf2 are known to regulate expression and coordinated induction of NQO1 and other detoxifying enzyme genes in response to antioxidants and xenobiotics. A cytosolic inhibitor of Nrf2, INrf2, that retains Nrf2 in the cytoplasm, was cloned and sequenced. Treatment of cells with antioxidants and xenobiotics results in the release of Nrf2 from INrf2. Nrf2 then moves in the nucleus. This leads to the induction of ARE-mediated NQO1 and other detoxifying enzyme genes expression. INrf2 after dissociation from Nrf2 remains in the cytosol. Overexpression of INrf2 repressed ARE-mediated NQO1 gene expression. Deletion mapping of INrf2 revealed the requirement of KELCH domain (amino acid residues 361-597) and C-terminal region (amino acid residues 598-624) in retention of Nrf2 in the cytosol. Both these regions of INrf2 independently retained Nrf2 in the cytosol leading to the repression of ARE-mediated NQO1 gene expression. These results may indicate that two different regions of INrf2 interact with a single molecule of Nrf2 or two or more molecules of Nrf2 interact with a single molecule of INrf2. The transcription of Nrf2 and INrf2 did not change in response to antioxidants and xenobiotics. This indicated that INrf2 and/or Nrf2 might be post-transcriptionally modified in response to antioxidants and xenobiotics leading to the release of Nrf2 from INrf2 and induction of ARE-mediated NQO1 and other detoxifying enzyme genes expression.

In vivo role of NAD(P)H:quinone oxidoreductase 1 (NQO1) in the regulation of intracellular redox state and accumulation of abdominal adipose tissue

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a flavoprotein that utilizes NAD(P)H as an electron donor, catalyzing the two-electron reduction and detoxification of quinones and their derivatives. NQO1-/- mice deficient in NQO1 activity and protein were generated in our laboratory (Rajendirane, V., Joseph, P., Lee, Y. H., Kimura, S., Klein-Szanto, A. J. P., Gonzalez, F. J., and Jaiswal, A. K. (1998) J. Biol. Chem. 273, 7382-7389). Mice lacking a functional NQO1 gene (NQO1-/-) were born normal and reproduced adeptly as the wild-type NQO1+/+ mice. In the present report, we show that NQO1-/- mice exhibit significantly lower levels of abdominal adipose tissue as compared with the wild-type mice. The NQO1-/- mice showed lower blood levels of glucose, no change in insulin, and higher levels of triglycerides, beta-hydroxy butyrate, pyruvate, lactate, and glucagon as compared with wild-type mice. Insulin tolerance test demonstrated that the NQO1-/- mice are insulin resistant. The NQO1-/- mice livers also showed significantly higher levels of triglycerides, lactate, pyruvate, and glucose. The liver glycogen reserve was found decreased in NQO1-/- mice as compared with wild-type mice. The livers and kidneys from NQO1-/- mice also showed significantly lower levels of pyridine nucleotides but an increase in the reduced/oxidized NAD(P)H:NAD(P) ratio. These results suggested that loss of NQO1 activity alters the intracellular redox status by increasing the concentration of NAD(P)H. This leads to a reduction in pyridine nucleotide synthesis and reduced glucose and fatty acid metabolism. The alterations in metabolism due to redox changes result in a significant reduction in the amount of abdominal adipose tissue.

Small maf (MafG and MafK) proteins negatively regulate antioxidant response element-mediated expression and antioxidant induction of the NAD(P)H:Quinone oxidoreductase1 gene

The antioxidant response element (ARE) is known to regulate expression and induction of NQO1, GST Ya, and other detoxifying enzyme genes in response to antioxidants and xenobiotics. The nuclear transcription factor Nrf2 and Nrf1 bind to the ARE and positively regulate expression and induction of the NQO1 and GST Ya genes. In this study, we demonstrate that overexpression of small Maf (MafG and MafK) proteins negatively regulate ARE-mediated expression and tert-butyl hydroquinone induction of the NQO1 and GST Ya genes in transfected Hep-G2 cells. In similar experiments, overexpression of small Maf proteins also repressed Nrf2-mediated up-regulation of ARE-mediated NQO1 and GST Ya genes expression in Hep-G2 cells co-transfected with Nrf2 and small Maf proteins. Band and supershift assays with the NQO1 gene ARE and nuclear proteins demonstrate that small MafG and MafK bind to the ARE as Maf-Maf homodimers and Maf-Nrf2 heterodimers. Therefore, Maf-Maf homodimers and possibly Maf-Nrf2 heterodimers play a role in negative regulation of ARE-mediated transcription and antioxidant induction of NQO1 and other detoxifying enzyme genes. In contrast to Maf-Nrf2, the Maf-Nrf1 heterodimers failed to bind with the NQO1 gene ARE and did not demonstrate the repressive effect in transfection assays.

NRH:quinone oxidoreductase2 (NQO2)

The quinone oxidoreductases [NAD(P)H:quinone oxidoreductase1 (NQO1) and NRH:quinone oxidoreductase2 (NQO2)] are flavoproteins. NQO1 is known to catalyse metabolic detoxification of quinones and protect cells from redox cycling, oxidative stress and neoplasia. NQO2 is a 231 amino acid protein (25956 mw) that is 43 amino acids shorter than NQO1 at its carboxy-terminus. The human NQO2 cDNA and protein are 54 and 49% similar to the human liver cytosolic NQO1 cDNA and protein. Recent studies have revealed that NQO2 differs from NQO1 in its cofactor requirement. NQO2 uses dihydronicotinamide riboside (NRH) rather than NAD(P)H as an electron donor. Another difference between NQO1 and NQO2 is that NQO2 is resistant to typical inhibitors of NQO1, such as dicoumarol, Cibacron blue and phenindone. Flavones, including quercetin and benzo(a)pyrene, are known inhibitors of NQO2. Even though overlapping substrate specificities have been observed for NQO1 and NQO2, significant differences exist in relative affinities for the various substrates. Analysis of the crystal structure of NQO2 revealed that NQO2 contains a specific metal binding site, which is not present in NQO1. The human NQO2 gene has been precisely localized to chromosome 6p25. The human NQO2 gene locus is highly polymorphic. The NQO2 gene is ubiquitously expressed and induced in response to TCDD. Nucleotide sequence analysis of the NQO2 gene promoter revealed the presence of several cis-elements, including SP1 binding sites, CCAAT box, xenobiotic response element (XRE) and an antioxidant response element (ARE). The complement of these elements regulates tissue specific expression and induction of the NQO2 gene in response to xenobiotics and antioxidants. The in vivo role of NQO2 and its role in quinone detoxification remains unknown.

NAD(P)H:quinone oxidoreductase 1 deficiency increases susceptibility to benzo(a)pyrene-induced mouse skin carcinogenesis

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a flavoprotein that catalyzes the metabolic detoxification of quinones and their derivatives. This protects cells against quinone-induced oxidative stress, cytotoxicity, and mutagenicity. C57BL6 NQO1-/- mice, deficient in NQO1 RNA and protein, were generated in our laboratory. To investigate the role of NQO1 in chemical carcinogenesis, the dorsal skin of NQO1-deficient (NQO1-/-) and wild-type (NQO1+/+) mice were treated with a single dose of benzo(a)pyrene, followed by twice weekly applications of phorbol-12-myristate-13-acetate. The NQO1-/- mice showed a much higher frequency of skin tumor development when compared with their wild-type littermates. Interestingly, the male NQO1-/- mice were slower to develop skin tumors than their NQO1-/- female littermates. Histological analysis of the NQO1-/- tumors showed proliferative activity. These results demonstrate that NQO1 acts as an endogenous factor in protection against benzo(a)pyrene carcinogenicity.

Antioxidant regulation of genes encoding enzymes that detoxify xenobiotics and carcinogens

Antioxidants are substances that delay or prevent the oxidation of cellular oxidizable substrates. The various antioxidants exert their effect by scavenging superoxide or by activating a battery of detoxifying/defensive proteins. In this chapter, we have focused on the mechanisms by which antioxidants induce gene expression. Many xenobiotics (e.g., beta-naphthoflavone) activate genes similar to those activated by antioxidants. The promoters of these genes contain a common cis-element, termed the antioxidant response element (ARE), which contains two TRE (TPA response element) or TRE-like elements followed by GC box. Mutational studies have identified GTGAC***GC as the core of the ARE sequence. Many transcription factors, including Nrf, Jun, Fos, Fra, Maf, YABP, ARE-BP1, Ah (aromatic hydrocarbon) receptor, and estrogen receptor bind to the ARE from the various genes. Among these factors, Nrf-Jun heterodimers positively regulate ARE-mediated expression and induction of genes in response to antioxidants and xenobiotics. This Nrf-Jun heterodimerization and binding to the ARE requires unknown cytosolic factors. The mechanism of signal transduction from antioxidants and xenobiotics includes several steps: (1) Antioxidants and xenobiotics undergo metabolism to generate superoxide and related reactive species, leading to the generation of a signal to activate expression of detoxifying/defensive genes. (2) The generation of superoxide and related reactive species is followed by activation of yet to be identified cytosolic factors by unknown mechanism(s). (3). Activated cytosolic factors catalyze modification of Nrf and/or Jun proteins, which bind to the ARE in promoters of the various detoxifying/defensive genes. (4) The transcription of genes encoding detoxifying/defensive proteins is increased. The unknown cytosolic factors are significant molecules because they represent the oxidative sensors within the cells. Identification of the cytosolic factors will be of considerable importance in the field of antioxidants and gene regulation research. Future studies will also be required to completely understand the molecular mechanism of signal transduction from antioxidants and xenobiotics to Nrf-Jun. In addition to the Nrf-Jun pathway, mammalian cells also contain other pathways that activate gene expression in response to oxidative stress. These include NF-KB-, HIF-1-, Mac-1-, and SRF-mediated pathways. It is expected that collectively these pathways increase transcription of more than four dozen genes to protect cells against oxidative stress.

An unusual case of primary lymphoma of the skull base extending from cerebellopontine angle to cavernous sinus and orbit. A case report

The authors describe a rare case of a primary central nervous system lymphoma of the cerebellopontine angle, extending into the right cavernous sinus and orbit. The patient presented with multiple right sided cranial nerve palsies and rapidly progressive proptosis and ophthalmoplegia of the right eye. Imaging revealed a cerebellopontine angle mass extending into cavernous sinus. Surgical decompression of the tumor was undertaken through a right sided retromastoid craniectomy. Histopathology revealed Non Hodgkin's lymphoma of diffuse large cell type. There was no evidence of systemic lymphoma. Primary lymphoma of cerebellopontine angle with direct extension into cavernous sinus and orbit is rare and to our knowledge this is the only case reported.

Regulation of genes encoding NAD(P)H:quinone oxidoreductases

NAD(P)H:quinone oxidoreductase (NQO1) and NRH:quinone oxidoreductase (NQO2) are flavoproteins that catalyze two-electron reduction and detoxification of quinones and its derivatives. This leads to the protection of cells against redox cycling, oxidative stress, and neoplasia. NQO1 is expressed ubiquitously in all the tissues. However, the level of expression varied among the human tissues. NQO1 gene is expressed at higher levels in several tumor tissue types, including liver and colon, as compared to normal tissues of similar origin. NQO1 gene expression is coordinately induced with other detoxifying enzyme genes in response to xenobiotics, antioxidants, oxidants, heavy metals, and radiations. Deletion mutagenesis in the NQO1 gene promoter identified several cis-elements including antioxidant response element (ARE), a basal element, and AP-2 element. ARE elements have also been found in the promoter regions of other detoxifying enzyme genes including glutathione S-transferases. ARE is essentially required for expression and coordinated induction of NQO1 and other detoxifying enzyme genes. Nuclear transcription factors Nrf2 and c-Jun bind to the ARE and activate the gene expression. The binding of Nrf2 + c-Jun to the ARE required unknown cytosolic factor(s). In addition to Nrf2 and c-Jun, other nuclear transcription factors including Nrf1, Jun-B, and Jun-D also bind to the ARE and regulate expression and induction of NQO1 gene. A hypothetical model is presented based on the available information on ARE-mediated regulation of detoxifying enzyme genes. Briefly, the Nrf2 is retained in the cytosplasm by a repressor protein Keap1 in untreated normal cells. The treatment of cells with xenobiotics and antioxidants leads to the activation of unknown cytosolic factor(s) that catalyze modification of Nrf2 and/or Keap1. The modification follows dissociation of Nrf2 and Keap1. The free Nrf2 translocates in the nucleus. Nrf2 in the nucleus heterodimerizes with c-Jun and binds to the ARE resulting in the induction of NQO1 and other ARE-regulated genes expression. The identity of cytosolic factor(s) remains unknown.

Role of NAD(P)H:quinone oxidoreductase 1 (DT diaphorase) in protection against quinone toxicity

NQO1-/- mice, along with Chinese hamster ovary (CHO) cells, were used to determine the in vivo role of NAD(P)H:quinone oxidoreductase 1 (NQO1) in cellular protection against quinone cytotoxicity, membrane damage, DNA damage, and carcinogenicity. CHO cells permanently expressing various levels of cDNA-derived P450 reductase and NQO1 were produced. Treatment of CHO cells overexpressing P450 reductase with menadione, benzo[a]pyrene-3,6-quinone (BPQ), and benzoquinone led to increased cytotoxicity as compared with CHO cells expressing endogenous P450 reductase. In a similar experiment, overexpression of NQO1 significantly protected CHO cells against the cytotoxicity of these quinones. Knockout (NQO1-/-) mice deficient in NQO1 protein and activity had been generated previously in our laboratory and were used in the present studies. Wild-type (NQO1+/+) and knockout (NQO1-/-) mice were given i.p. injections of menadione and BPQ, followed by analysis of membrane damage and DNA damage. Both menadione and BPQ induced lipid peroxidation in hepatic and non-hepatic tissues, indicating increased membrane damage. Exposure to BPQ also resulted in increased hepatic DNA adducts in NQO1-/- mice as compared with NQO1+/+ mice. The skin application of BPQ alone and BPQ + 12-O-tetradecanoylphorbol-13-acetate (TPA) failed to induce papillomas, or other lesions, for up to 50 weeks in either NQO1+/+ or NQO1-/- mice. The various results from CHO cells and NQO1-/- mice indicated that NQO1 protects against quinone-induced cytotoxicity, as well as DNA and membrane damage. The absence of BPQ-induced skin carcinogenicity in NQO1-/- mice may be related to the strain (C57BL/6) of mice used in the present study and/or due to poor BPQ absorption into the skin and/or due to detoxification of BPQ by cytosolic NRH:quinone oxidoreductase 2 (NQO2).

Mouse NRH:quinone oxidoreductase (NQO2): cloning of cDNA and gene- and tissue-specific expression

The mouse NQO2 cDNA and gene with flanking regions were cloned and sequenced. Analysis of the primary structure of the mouse NQO2 protein revealed the presence of glycosylation, myristylation, protein kinase C and caseine kinase II phosphorylation sites. These sites are conserved in the human NQO2 protein. The mouse NQO2 gene promoter contains several important cis-elements, including the antioxidant response element (ARE), the xenobiotic response element (XRE), and an Sp1 binding site. Northern analysis of eight mouse tissues indicated wide variations in the expression of the NQO2 and NQO1 genes. NQO2 gene expression was higher in liver and testis compared with the NQO1 gene, which was highest in the heart. NQO1 gene expression was undetectable in the testis. Mouse kidney showed significantly higher expression levels of NQO1 compared with NQO2. Brain, spleen, lung, and skeletal muscle showed undetectable levels of NQO2 and NQO1 gene expression. NQO2 activity followed a more or less similar pattern of tissue-specific expression as NQO2 RNA. Interestingly, the NQO2 activity remained unchanged in the NQO1-/-mice tissues compared with NQO1+/+ mice, with the exception of the liver. The livers from NQO1-/-mice showed a 45% increase in NQO2 activity compared with the NQO1+/+ mice. The mouse NQO2 cDNA was subcloned into the pMT2 eukaryotic expression vector which, upon transfection in monkey kidney COS1 cells, produced a significant increase in NQO2 activity. Deletion of 54 amino acids from the N-terminus of the mouse NQO2 protein resulted in the loss of NQO2 expression and activity in transfected COS1 cells. This indicates that deletion of exon(s) encoding the N-terminus of NQO2 from the endogenous gene in mouse embryonic (ES) stem cells should result in NQO2-null mice.

Folliculitis decalvans in a family

Two cases of folliculitis decalvans in a family are reported for its rarity and clinical interest.

Cerebellar medulloblastoma in a 65 year old Indian male

A case of cerebellar medulloblastoma in a 65 year old male is reported. Cerebellar medulloblastoma is classically seen during childhood, and less than 25% of these tumours are found in adults below 40 years of age. Rarely, cases are reported above the age of 40 years. So far only three cases have been reported in patients aged above 64 years and none of these case reports are from India.

Nrf2 and c-Jun regulation of antioxidant response element (ARE)-mediated expression and induction of gamma-glutamylcysteine synthetase heavy subunit gene

gamma-Glutamylcysteine synthetase (gamma-GCS) is a rate-limiting enzyme in the de novo synthesis of glutathione, a known scavenger of electrophiles and reactive oxygen species (ROS). The gamma-GCS gene is expressed ubiquitously and induced coordinately with NAD(P)H:quinone oxidoreductase(1) (NQO1) and glutathione S-transferase Ya (GST Ya) in response to xenobiotics and antioxidants. The antioxidant response element (ARE) is required for expression and induction of these genes. In the current report, we demonstrated that ARE-mediated gamma-GCS gene expression and induction is regulated by similar Nrf and Jun factors as reported earlier for the NQO1 and GST Ya genes. The gamma-GCS gene ARE competed with the binding of nuclear proteins (Nrf + Jun) to the NQO1 gene ARE (hARE). In addition, the overexpression of Nrf2 and Nrf1 with c-Jun significantly up-regulated gamma-GCS ARE-mediated basal expression and beta-naphthoflavone induction of the chloramphenicol acetyltransferase gene in transfected HepG2 cells. Interestingly, Nrf2 + c-Jun was more effective than Nrf1 + c-Jun in the regulation of ARE-mediated gamma-GCS gene expression. Further experiments demonstrated that the c-Jun level within the cells is an important determinant of the level of ARE-mediated gamma-GCS gene expression. Therefore, at higher concentrations of c-Jun, gamma-GCS gene expression is repressed, presumably due to generation of a sufficient amount of c-Jun + c-Fos complex that interferes with the binding of Nrf2 + c-Jun complex to the ARE.