Amanjit Bal

Fungal Rhinosinusitis: A Categorization and Definitional Schema Addressing Current Controversies

Fungal (rhino‐) sinusitis encompasses a wide spectrum of immune and pathological responses, including invasive, chronic, granulomatous, and allergic disease. However, consensus on terminology, pathogenesis, and optimal management is lacking. The International Society for Human and Animal Mycology convened a working group to attempt consensus on terminology and disease classification.

Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration vs Conventional Transbronchial Needle Aspiration in the Diagnosis of Sarcoidosis

BACKGROUND Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is superior to conventional transbronchial needle aspiration (cTBNA) in the staging of lung cancer. However, its efficiency in diagnosis of sarcoidosis when combined with endobronchial biopsy (EBB) and transbronchial lung biopsy (TBLB) has not been studied. This randomized controlled trial compares diagnostic yield of EBUS-TBNA vs cTBNA in combination with EBB and TBLB. METHODS Patients with clinical diagnosis of sarcoidosis were randomized 1:1 to EBUS-TBNA or cTBNA. All patients underwent TBLB and EBB. The primary outcome was detection of granulomas. The secondary end points were the individual and cumulative yields of various procedures, serious adverse events, and procedure time. RESULTS Of the 130 patients, sarcoidosis was diagnosed in 117 (62 cTBNA, 55 EBUS-TBNA). The two groups were similar at baseline. Granulomas were demonstrated in 104 (53 cTBNA, 51 EBUS-TBNA) patients and were similar in two groups (85.5% vs 92.7%, P = .34). Individually, EBUS-TBNA had the highest yield (41 of 55, 74.5%), which was better than cTBNA (30 of 62, 48.4%, P = .004) or EBB (40 of 111, 36.3%, P < .0001) but not TBLB (78 of 112, 69.6%, P = .54). Adding EBB/TBLB to cTBNA led to an increase in granuloma detection, whereas the addition of TBLB (but not EBB) significantly enhanced the yield of EBUS-TBNA. The procedure time was significantly longer with EBUS-TBNA. No major adverse events occurred. CONCLUSIONS Individually, EBUS-TBNA has the highest diagnostic yield in sarcoidosis, but it should be combined with TBLB for the optimal yield. The diagnostic yield of cTBNA (plus EBB and TBLB) is similar to EBUS-TBNA plus TBLB. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT01908868; URL: www.clinicaltrials.gov.

Impairment of mitochondrial energy metabolism in different regions of rat brain following chronic exposure to aluminium.

The present study was designed with an aim to evaluate the effects of chronic aluminium exposure (10 mg/kg b.wt, intragastrically for 12 weeks) on mitochondrial energy metabolism in different regions of rat brain in vivo. Mitochondrial preparations from aluminium treated rats revealed significant decrease in the activity of various electron transport complexes viz. cytochrome oxidase, NADH cytochrome c reductase and succinic dehydrogenase as well, in the hippocampus region. The decrease in the activity of these respiratory complexes was also seen in the other two regions viz. corpus striatum and cerebral cortex, but to a lesser extent. This decrease in the activities of electron transport complexes in turn affected the ATP synthesis and ATP levels adversely in the mitochondria isolated from aluminium treated rat brain regions. We also studied the spectral properties of the mitochondrial cytochromes viz. cyt a, cyt b, cyt c1, and cyt c in both control and treated rat brains. The various cytochrome levels were found to be decreased following 12 weeks of aluminium exposure. Further, these impairments in mitochondrial functions may also be responsible for the production of reactive oxygen species and impaired antioxidant defense system as observed in our study. The electron micrographs of neuronal cells depicted morphological changes in mitochondria as well as nucleus only from hippocampus and corpus striatum regions following 12 weeks exposure to aluminium. The present study thus highlights the significance of altered mitochondrial energy metabolism and increased ROS production as a result of chronic aluminium exposure in different regions of the rat brain.

Mitochondrial energy metabolism impairment and liver dysfunction following chronic exposure to dichlorvos.

Although the effects of acute pesticide poisoning are well known but, hardly any data exists regarding the health effects after long-term low-level exposure. Major unresolved issues include the effect of moderate exposure in the absence of poisoning. The present study elucidates a possible mechanism by which chronic organophosphate exposure (dichlorvos 6 mg/kg b.wt., s.c. for 12 weeks) causes liver dysfunction. Mitochondria, a primary site of cellular energy generation and oxygen consumption represent a likely target for organophosphate poisoning. Therefore, the objective of the current study was planned with an aim to investigate the effect of chronic dichlorvos exposure on liver mitochondrial electron transport chain (ETC), mitochondrial calcium uptake and its implications on the induction of liver enzymes and liver dysfunction in rodent model. Our results indicated decreased mitochondrial electron transfer activities of cytochrome oxidase along with altered mitochondrial complexes I and II activity. This decrease in the activities of electron transport complexes in turn affected the ATP synthesis and ATP levels adversely in the mitochondria isolated from dichlorvos (DDVP) treated rat liver. Mitochondrial preparation from DDVP treated rat liver demonstrated significant increase in mitochondrial Ca(2+) uptake and increase ROS levels. The alterations in the mitochondrial calcium uptake, mitochondrial electron transfer enzyme activities and increase ROS levels in turn might have caused an increase in liver enzymes (ALT, AST and ALP). The electron micrographs of liver cells depicted morphological changes in mitochondria as well as nucleus following 12 weeks of exposure to DDVP. These studies provide an evidence of impaired mitochondrial bioenergetics which may lead to liver dysfunction after chronic exposure to dichlorvos.

Susceptibility of mitochondrial superoxide dismutase to aluminium induced oxidative damage

Aluminium has been implicated in various neurodegenerative diseases but exact mechanism of action is still not known. Mitochondria being a major site of reactive oxygen species production are considered to be target of oxidative stress and it seems that the oxidative damage to mitochondrial proteins may underlie the pathogenesis of aluminium induced neurodegeneration. Thus, the present study was undertaken to reveal the effects of chronic aluminium exposure (10mg/kg b.wt, intragastrically for 12 weeks) on the oxidative damage to mitochondrial proteins in male albino Wistar rats. Chronic aluminium exposure resulted in decrease in the activity of mitochondrial superoxide dismutase (MnSOD) and aconitase in different regions of rat brain suggesting increased oxidative stress. This decrease in MnSOD activity in turn might be responsible for the increased protein oxidation as observed in our study. All these processes taken together may cause increased oxidative damage to mitochondrial proteins in general. By taking the advantage of recent immunochemical probe for oxidatively modified proteins, we identified MnSOD to be susceptible to oxidative damage in aluminium treated animals. The quantitative RT-PCR analysis for Lon protease, a protease involved in the removal of oxidatively modified proteins from mitochondria, showed decreased mRNA expression suggesting increased oxidative damage and decreased removal of mitochondrial proteins. The identification of specific proteins as targets of oxidative damage may provide new therapeutic measures to reverse the effects of aluminium induced neurodegeneration.

Spectrum of fungal rhinosinusitis; histopathologist's perspective

Aims: Clinical presentation can provide a clue to the subcategories of fungal rhinosinusitis (FRS); however, tissue examination provides accurate classification. The aim was to analyse the incidence and histopathological spectrum of FRS.

Aluminium-induced oxidative DNA damage recognition and cell-cycle disruption in different regions of rat brain.

The present study was undertaken to reveal the effects of chronic aluminium exposure (10 mg/kg/b.wt, intragastrically for 12 weeks) on the oxidative DNA damage and its implication on the expression of p53 and other cell-cycle regulatory proteins in male Wister rats. Chronic aluminium exposure resulted in increased formation of 8-hydoxydeoxyguanosine in the mitochondrial DNA isolated from different regions of rat brain. The agarose gel electrophoresis revealed the DNA fragmentation pattern in aluminium-treated rat brain regions. Increased expression of p53 demonstrated that aluminium induces DNA damage. Western blot and mRNA expression analysis demonstrated increased expression of cyclin D1, suggesting disruption of cell cycle. The immunohistochemical studies showed nuclear localization of p53; however, the localization of cyclin D1 was both cytoplasmic and nuclear in aluminium-treated rat brain regions. Thus, the findings of the present study reveal that aluminium-induced oxidative damage to DNA may be involved in the neurodegeneration via increase in p53 expression and activation of cell cycle.

Nigrostriatal neuronal death following chronic dichlorvos exposure: crosstalk between mitochondrial impairments, α synuclein aggregation, oxidative damage and behavioral changes

BackgroundIn recent years, several lines of evidence have shown an increase in Parkinsons disease prevalence in rural environments where pesticides are heavily used. Although, the underlying mechanism for neuronal degeneration in sporadic PD remains unknown, mitochondrial dysfunction, oxidative stress and proteasomal dysfunction are proposed as contributing factors. In this study rats were chronically and continuously exposed to the pesticide, dichlorvos to identify the molecular mechanism of nigrostaital neuronal degeneration.ResultChronic dichlorvos exposure (2.50 mg/kg b.wt.s.c/daily for 12 weeks) caused nigrostriatal dopaminergic degeneration. The degenerative changes were accompanied by a loss of 60-80% of the nigral dopamine neurons and 60-70% reduction in striatal dopamine and tyrosine hydroxylase levels. Dichlorvos exposed animals also showed α -synuclein and ubiquitin positive inclusions along with swollen, dystrophic neurites and mitochondrial abnormalities like decreased complex I&IV activities, increased mitochondrial size, axonal degeneration and presence of electron dense perinuclear cytoplasmic inclusions in the substantia nigra of rats. These animals also showed evidence of oxidative stress, including increased mitochondrial ROS levels, decreased MnSOD activity and increased lipid peroxidation. Measurable impairments in neurobehavioral indices were also observed. Notable exacerbations in motor impairments, open field and catalepsy were also evident in dichlorvos exposed animals.ConclusionAll these findings taken together indicate that chronic dichlorvos exposure may cause nigrostaital neurodegenaration and significant behavioral impairments.

Protective efficacy of mitochondrial targeted antioxidant MitoQ against dichlorvos induced oxidative stress and cell death in rat brain

Dichlorvos is a synthetic insecticide that belongs to the family of chemically related organophosphate (OP) pesticides. It can be released into the environment as a major degradation product of other OPs, such as trichlorfon, naled, and metrifonate. Dichlorvos exerts its toxic effects in humans and animals by inhibiting neural acetylcholinesterase. Chronic low-level exposure to dichlorvos has been shown to result in inhibition of the mitochondrial complex I and cytochrome oxidase in rat brain, resulting in generation of reactive oxygen species (ROS). Enhanced ROS production leads to disruption of cellular antioxidant defense systems and release of cytochrome c (cyt c) from mitochondria to cytosol resulting in apoptotic cell death. MitoQ is an antioxidant, selectively targeted to mitochondria and protects it from oxidative damage and has been shown to decrease mitochondrial damage in various animal models of oxidative stress. We hypothesized that if oxidative damage to mitochondria does play a significant role in dichlorvos induced neurodegeneration, then MitoQ should ameliorate neuronal apoptosis. Administration of MitoQ (100 μmol/kg body wt/day) reduced dichlorvos (6 mg/kg body wt/day) induced oxidative stress (decreased ROS production, increased MnSOD activity and glutathione levels) with decreased lipid peroxidation, protein and DNA oxidation. In addition, MitoQ also suppressed DNA fragmentation, cyt c release and caspase-3 activity in dichlorvos treated rats compared to the control group. Further electron microscopic studies revealed that MitoQ attenuates dichlorvos induced mitochondrial swelling, loss of cristae and chromatin condensation. These results indicate that MitoQ may be beneficial against OP (dichlorvos) induced neurodegeneration.

Neurobehavioral impairments, generation of oxidative stress and release of pro-apoptotic factors after chronic exposure to sulphur mustard in mouse brain.

Recent global events have focused attention on the potential threat of international and domestic chemical terrorism, as well as the possibility of chemical warfare proliferation. Sulphur mustard (SM) is one of the potent chemical warfare agents (CWA), which initiates a cascade of events that converge on the redox mechanisms common to brain injury. The present study was designed to examine the effects of chronic SM exposure on neurobehavioral impairments, mitochondrial oxidative stress in male Swiss Albino mice and its role in inducing apoptotic neuronal cell death. The animals were divided into four groups (control, low, medium and high dose) of 5 animals each. Exposure to SM was given percutaneously daily for 12 weeks. The results demonstrated impairment in neurobehavioral indices viz. rota rod, passive avoidance and water maze tests in a dose dependent manner. There was a significant increase in lipid peroxidation and protein carbonyl content whereas, decrease in the activity of manganese superoxide dismutase (MnSOD), glutathione reductase and glutathione peroxidase suggesting impaired antioxidant defense system. Immunoblotting of cytochrome c, Bcl-2, Bax and activation of caspase-3 suggest induction of apoptosis in a dose dependent manner. Finally, increased p53 expression suggests that it may target the mitochondrial pathway for inducing apoptosis in response to DNA damage signals. In conclusion, chronic SM exposure may have the potential to generate oxidative stress which may trigger the release of cytochrome c as well as caspase-3 activation in neurons leading to cell death by apoptosis in a dose dependent manner which may in the end be responsible for the disruption of cognitive functions in mice.