Approach to non-compressive myeloneuropathy through a rendezvous of 11 cases from an Indian backdrop.

Introduction: Myeloneuropathy is a diagnosis ascribed to disorders that concomitantly affect the spinal cord and peripheral nerves. Recognizing this syndrome may sometimes be arduous, even for the most consummate clinicians, because symptomatology can mimic either spinal cord or peripheral nerve disease. Besides, examination findings suggest a predominantly myelopathic or neuropathic picture. This article reports a rendezvous of rare cases of clinically diagnosed myeloneuropathy with different etiological backgrounds and therapeutic responses. Methods: Eleven cases of non-compressive myeloneuropathy were admitted to the Department of General Medicine of Burdwan Medical College and Hospital, Burdwan, West Bengal, India, between May 2018 and May 2022. Results: We report the cases of 11 patients (6 men and 5 women) who presented with myeloneuropathy of different etiologies (vitamin B12, copper, and vitamin E deficiencies, organophosphate poisoning, chronic alcohol abuse, illicit substances abuse, anti-thyroid peroxidase/anti-thyroglobulin antibody-related neurologic disorder responsive to steroids, Sjögren syndrome, chikungunya infection, paraneoplastic, and hereditary). Conclusion: Meticulous historical analysis, careful clinical examination, and apposite utilization and interpretation of biochemical, electrophysiological, and neuroimaging findings are sine-qua-non for an accurate and consistent approach to evaluating a suspected case of myeloneuropathy, facilitating early treatment and recovery. Differential identification of these disorders needs an in-depth perception of the mode of onset of symptoms, the course of progression of the disease, the pattern of myelopathic/neuropathic findings, and recognition of other neurological or systemic manifestations. For untroubled understanding, etiologies of myeloneuropathies should be subdivided into a few broad categories, e.g., metabolic (nutritional), toxic (toxin-induced), infectious, inflammatory (immune-mediated), paraneoplastic, and hereditary disorders.

Introducción: La mieloneuropatía es un síndrome que afecta concomitantemente la médula espinal y los nervios periféricos. Reconocerlo a veces puede ser arduo, incluso para los médicos más experimentados, porque la sintomatología puede simular una enfermedad de la médula espinal o de los nervios periféricos. Además, los hallazgos del examen sugieren un cuadro predominantemente mielopático o neuropático. Este artículo describe una serie de casos raros de mieloneuropatía de distintas causas y con respuestas terapéuticas distintas. Métodos: Once casos de mieloneuropatía no compresiva fueron ingresados en el Departamento de Medicina General del Burdwan Medical College, and Hospital, Burdwan, Bengala Occidental, India, entre mayo de 2018 y mayo de 2022. Resultados: Presentamos 11 pacientes (seis hombres y cinco mujeres) con mieloneuropatía de diferentes etiologías (deficiencias de vitamina B12, cobre y vitamina E, intoxicación por organofosforados, abuso crónico de alcohol, abuso de sustancias ilícitas, trastorno neurológico relacionado con anticuerpos anti-tiroglobulina / antiperoxidasa tiroidea que responde a esteroides, síndrome de Sjögren, infección por chikungunya, paraneoplásico y hereditario). Conclusión: El análisis meticuloso de la historia y del examen clínico, así como la utilización e interpretación adecuadas de los hallazgos bioquímicos, electrofisiológicos y de neuroimagen son condiciones sine qua non para un enfoque preciso y consistente para evaluar un caso sospechoso de mieloneuropatía, lo que facilita el tratamiento temprano y su recuperación. El diagnóstico diferencial de esta patología requiere un conocimiento del modo de inicio de los síntomas, su progresión, el patrón de hallazgos mielopáticos/neuropáticos y el reconocimiento de otras manifestaciones neurológicas o sistémicas. Las etiologías de las mieloneuropatías deben subdividirse en trastornos metabólicos (nutricionales), tóxicos (inducidos por toxinas), infecciosos, inflamatorios (mediados por mecanismos inmunitarios), paraneoplásicos y hereditarias.

Androgen deprivation-induced elevated nuclear SIRT1 promotes prostate tumor cell survival by reactivation of AR signaling.

The NAD+-dependent deacetylase, Sirtuin 1 (SIRT1) is involved in prostate cancer pathogenesis. However, the actual contribution is unclear as some reports propose a protective role while others suggest it is harmful. We provide evidence for a contextual role for SIRT1 in prostate cancer. Our data show that (i) mice orthotopically implanted with SIRT1-silenced LNCaP cells produced smaller tumors; (ii) SIRT1 suppression mimicked AR inhibitory effects in hormone responsive LNCaP cells; and (iii) caused significant reduction in gene signatures associated with E2F and MYC targets in AR-null PC-3 and E2F and mTORC1 signaling in castrate-resistant ARv7 positive 22Rv1 cells. Our findings further show increased nuclear SIRT1 (nSIRT1) protein under androgen-depleted relative to androgen-replete conditions in prostate cancer cell lines. Silencing SIRT1 resulted in decreased recruitment of AR to PSA enhancer selectively under androgen-deprivation conditions. Prostate cancer outcome data show that patients with higher levels of nSIRT1 progress to advanced disease relative to patients with low nSIRT1 levels. Collectively, we demonstrate that lowering SIRT1 levels potentially provides new avenues to effectively prevent prostate cancer recurrence.

Heptachlor-induced epithelial to mesenchymal transition in HK-2 cells mediated via TGF-ß1/Smad signalling.

This study investigated the effect of heptachlor-induced oxidative stress (OS) on transforming growth factor (TGF)-ß1-mediated epithelial to mesenchymal transition (EMT) in human renal proximal tubular epithelial (HK-2) cells. Following treatment of HK-2 cells with an increasing concentration of heptachlor (0.01-10 µM) for 24 h, the intracellular reactive oxygen species and malondialdehyde level increased, whereas the glutathione-s-hydroxylase (GSH) level declined significantly in a dose-dependent manner. Pretreatment with N-acetyl cysteine attenuates the heptachlor-induced OS. In this study, we have shown that heptachlor-induced OS regulates the mRNA expression of TGF-ß1-mediated Smad signalling genes accompanied by increased nuclear localization of phosphorylated Smad-2 and phosphorylated Smad-3. Furthermore, the m-RNA and protein level of epithelial marker, that is, E-cadherin decreased while the mesenchymal marker, that is, α-smooth muscle actin increased in heptachlor exposed HK-2 cells. In conclusion, heptachlor-induced OS might be responsible for the activation of TGF-ß1/Smad signalling which ultimately leads to renal damage by means of EMT.

Air pollution, weight loss and metabolic benefits of bariatric surgery: a potential model for study of metabolic effects of environmental exposures.

BACKGROUND: Emerging experimental evidence suggests that air pollution may contribute to development of obesity and diabetes, but studies of children are limited. OBJECTIVES: We hypothesized that pollution effects would be magnified after bariatric surgery for treatment of obesity, reducing benefits of surgery. METHODS: In 75 obese adolescents, excess weight loss (EWL), high-density lipoprotein (HDL) cholesterol, triglycerides, alkaline phosphatase (ALP) and hemoglobin A1c (HbA1c ) were measured prospectively at baseline and following laparoscopic adjustable gastric banding (LAGB). Residential distances to major roads and the average two-year follow-up exposure to particulate matter <2.5 µm (PM2.5 ), nitrogen dioxide (NO2 ) and ozone were estimated. Associations of exposure with change in outcome and with attained outcome two years post-surgery were examined. RESULTS: Major-roadway proximity was associated with reduced EWL and less improvement in lipid profile and ALP after surgery. NO2 was associated with less improvement in HbA1c and lower attained HDL levels and change in triglycerides over two years post-surgery. PM2.5 was associated with reduced EWL and reduced beneficial change or attained levels for all outcomes except HbA1c . CONCLUSIONS: Near-roadway, PM2.5 and NO2 exposures at levels common in developed countries were associated with reduced EWL and metabolic benefits of LAGB. This novel approach provides a model for investigating metabolic effects of other exposures.

Isolation of flavonoids from apple peel using novel graphene oxide cotton fiber.

A novel graphene oxide cotton fibre (GOF) was used to adsorb flavonoids from crude ethanol extracts derived from apple peels. Ultra-high pressure liquid chromatography-mass spectrometry was used to analyse polyphenol content, and the resulting data demonstrated that GOF-based flash chromatography can be used to efficiently separate polyphenols from sugars and can facilitate the removal of 95% of the sugar content. Flavonoids can be easily separated from phenolic acids. Chalcones and flavonols were eluted with 100% methanol and subsequently flavan-3-ols can be eluted with 0.04 M sodium hydroxide. The novel GOF has the potential to be used in the isolation of flavonoids.

Phase-sensitive amplification via coherent population oscillations in metastable helium at room temperature.

In this Letter, we report our experimental results on phase-sensitive amplification (PSA) in a nondegenerate signal-idler configuration using ultranarrow coherent population oscillations in metastable helium at room temperature. We achieved a high PSA gain of nearly 7 with a bandwidth of 200 kHz by using the system at resonance in a single-pass scheme. Further, the measured minimum gain is close to the ideal value, showing that we have a nearly pure PSA. This is also confirmed from our phase-to-phase transfer curves measurements, illustrating that we have a nearly perfect squeezer, which is interesting for a variety of applications.

Transcription addiction: can we garner the Yin and Yang functions of E2F1 for cancer therapy?

Classically, as a transcription factor family, the E2Fs are known to regulate the expression of various genes whose products are involved in a multitude of biological functions, many of which are deregulated in diseases including cancers. E2F is deregulated and hyperactive in most human cancers with context dependent, dichotomous and contradictory roles in almost all cancers. Cancer cells have an insatiable demand for transcription to ensure that gene products are available to sustain various biological processes that support their rapid growth and survival. In this context, cutting-off hyperactivity of transcription factors that support transcription dependence could be a valuable therapeutic strategy. However, one of the greatest challenges of targeting a transcription factor is the global effects on non-cancerous cells given that they control cellular functions in general. Recently, there is growing realization regarding the possibility to target the oncogenic activation of transcription factors to modulate transcription addiction without affecting the normal activity required for cell functions. In this review, we used E2F1 as a prototype transcription factor to address transcription factor activity in cancer cell functions. We focused on melanoma considering that E2F1 executes critical functions in response to UV, an etiological factor of cutaneous melanoma and lies immediately downstream of the CDKN2A/pRb axis, which is frequently deregulated in melanoma. Further, activation of E2F1 in melanomas can also occur independent of loss of CDKN2A. Given its activated status and the ability to transcriptionally control a plethora of genes involved in regulating melanoma development and progression, we review the current literature on its differential role in controlling signaling pathways involved in melanoma as well as therapeutic resistance, and discuss the practical value of weaning melanoma cells from E2F1-mediated transcription dependence for melanoma management.

Making ends meet: the importance of the N- and C-termini for the structure, stability, and function of the third SH3 domain of CIN85.

SH3 domains are common structure, interaction, and regulation modules found in more than 200 human proteins. In this report, we studied the third SH3 domain from the human CIN85 adaptor protein, which plays an important role in both receptor tyrosine kinase downregulation and phosphatidylinositol 3 kinase inhibition. The structure of this domain includes an additional 90° kink after the last canonical ß-strand and features unusual interactions between the termini well outside the boundaries of the standard SH3 domain definition. The extended portions of the domain are well-structured and held together entirely by side chain-side chain interactions. Extensive expression screening showed that these additional contacts provide significantly increased stability to the domain. A similar 90° kink is found in only one other SH3 domain structure, while side chain contacts linking the termini have never been described before. As a result of the increased size of CIN85 SH3 domain C, the proximal proline rich region is positioned such that a possible intramolecular interaction is structurally inhibited. Using the key interactions of the termini as the basis for sequence analysis allowed the identification of several SH3 domains with flanking sequences that could adopt similar structures. This work illustrates the importance of careful experimental analysis of domain boundaries even for a well-characterized fold such as the SH3 domain.

Emergency presentations of Parkinson's disease: early recognition and treatment are crucial for optimum outcome.

Parkinson's disease (PD) is a debilitating condition associated with significant morbidity and mortality. Pathophysiologically the illness is due to a disruption of dopamine production in the basal ganglia and leads to a wide array of symptoms. These symptoms are not restricted to the nervous system; thus, the illness often presents acutely to a wide range of specialties, many of which may have limited experience in the condition. Patients often become unwell with illnesses unrelated to their PD. However, these conditions frequently lead to a deterioration in PD control. In addition, there exist certain acute complications of PD which are often difficult to recognise and carry significant mortality. Discussing the acute presentations of the illness under the umbrella of PD is important as it enables clinicians to focus upon the specific concerns involved in managing patients with the illness. A number of conditions are extremely common in PD and include falls, orthostatic hypotension, swallowing difficulties, psychosis, and hyperkinetic movement disorders. Optimal treatment of these conditions requires the consideration of issues specific to PD. Lesser recognised acute presentations of PD include the serotonin syndrome and neuroleptic malignant-like syndrome. While encountered less commonly, these conditions have been well described in the literature and untreated may prove fatal. They require urgent management, with their importance being further highlighted by the fact they may often mimic other illnesses, making diagnosis difficult. Therapeutic interventions aimed at treating PD and preventing its complications are evolving rapidly.

Serious neutropenia following etanercept administration in a 62 years female patient of rheumatoid arthritis.

Tumor necrosis factor (TNF) plays an important role in the inflammatory process of RA and the resulting joint pathology. Etanercept is a member of anti TNF family which is indicated in patients with moderate to severe active rheumatoid arthritis either alone or in combination with MTX. Very few cases of neutropenia with etanercept treatment have been reported worldwide so far. The mechanism of etanercept induced neutropenia is not yet established. We report a case of 62 year female patient, developing etanercept induced neutropenia after 1 month of starting treatment. The absolute neutrophil count (ANC) came down to 150/microl on the 6th day of diagnosis. Bone marrow examination revealed a maturation arrest of granulocytic cells. Other marrow components were normal. Causality assessment of adverse drug reactions was done as per Naranjo's Algorithm. It was a probable ADR. We propose the possible mechanism of neutropenia is bone marrow toxicity. This is contrary to a previous case report which suggested peripheral consumption of neutrophil as a cause of neutropenia. Recently, there are some reports of leukemia and other hematological malignancies associated with the use of etanercept and in those conditions neutropenia could be the first manifestation. Neither product label of the drug nor US FDA warns for periodic blood investigation during etanercept therapy. There is a definite need for total and differential count estimation at the beginning and regular interval during etanercept treatment to rule out possibilities of neutropenia.

Enkephalinase inhibitors: potential agents for the management of pain.

Management of acute and chronic pain has always been a key area of clinical research. Enkephalinase inhibitors (EIs) seem to be promising as therapeutic agents having antinociceptive action. They additionally possess anticraving, antidiarrhoeal and antidepressant actions. The antinociceptive action of EIs has been reported for over a decade however, their therapeutic potential is yet to be effectively explored. EIs may be broadly classified as endogenous and those that are obtained synthetically. Endogenous EIs include peptides like spinorphin and opiorphin. And compounds like RB 101, RB 120, RB 3007 constitute the synthetically obtained EIs. Endogenous and synthetic inhibitors enkephalin degrading enzymes have been studied in vivo using standard animal models. The potential EI targets appear to be APN (Aminopeptidase N), NEP (Neutral endopeptidase), DPP-III (Dipeptidyl peptidase). EIs possess the advantage that they lack the opioid side effects. This article reviews the mechanisms by which EIs act and elucidates the pathways involved.

Antiinflammatory activity of a polyherbal formulation.

The antiinflammatory activity of the polyherbal formulation Entox(®) was investigated in rats for acute and sub acute models of inflammation using carrageenan-induced rat paw edema and cotton pellet granuloma methods respectively at a dose of 300 mg/kg and 600 mg/kg administered orally. The formulation in doses of 300 mg/kg and 600 mg/kg showed 51.61% and 54.84% inhibition of paw edema, respectively at the end of 3 h. The percent inhibition of granuloma by cotton pellet method was 27.92% and 53.17%, respectively. The formulation showed a significant antiinflammatory activity in both the experimental models and the activity was comparable to that of the standard drug, indomethacin.

Deregulation and cross talk among Sonic hedgehog, Wnt, Hox and Notch signaling in chronic myeloid leukemia progression.

Deciphering the BCR-ABL-independent signaling exploited in chronic myeloid leukemia (CML) progression is an important aspect in cancer stem-cell biology. CML stem-cell compartment is dynamic as it progresses to terminal blast crisis where myeloid and lymphoid blasts fail to differentiate. We demonstrate cross-regulation of signaling network involving Sonic hedgehog (Shh), Wnt, Notch and Hox for the inexorable blastic transformation of CD34(+) CML cells. Significant upregulation in Patched1, Frizzled2, Lef1, CyclinD1, p21 (P < or =0.0002) and downregulation of HoxA10 and HoxB4 (P< or =0.0001) transcripts in CD34(+) cells distinguish blast crisis from chronic CML. We report Shh-dependent Stat3 activation orchestrates these mutually interconnected signaling pathways. Stimulation of CD34(+) CML cells with either soluble Shh or Wnt3a did not activate Akt or p44/42-mitogen activated protein kinase (MAPK) pathways. Interestingly, unlike dominant negative Stat3beta, introduction of constitutive active Stat3 in CD34(+) CML cells induces cross-regulation in gene expression. Additionally, Shh and Wnt3a-dependent regulation of cyclin-dependent kinase inhibitors (CDKI) in CML suggests their role in the network. Taken together, our findings propose that deregulation in the form of hyperactive Shh and Wnt with repressed Notch and Hox pathways involving Stat3, Gli3, beta-catenin, CyclinD1, Hes1, HoxA10 and p21 might act synergistically to form an important hub in CML progression.

In vitro anti-resorptive activity and prevention of ovariectomy-induced osteoporosis in female Sprague-Dawley rats by ormeloxifene, a selective estrogen receptor modulator.

Antiosteoporotic activity of ormeloxifene, a multifunctional SERM, using inhibition in parathyroid hormone (PTH) induced resorption of 45Ca from prelabeled chick and rat fetal limb bones in chase cultures and modulation of certain biochemical markers of bone turnover and bone mineral density (BMD) in ovariectomized adult female rats, was investigated. Ormeloxifene concentration-dependently inhibited PTH-induced resorption of 45Ca from chick fetal femora with treated/control (T/C) ratio of 0.71, 0.32 and 0.20 at 50, 100 and 200 microM concentration, in comparison to 0.49, 0.53 and 0.95 in case of CDRI-85/287 (a pure antiestrogen), tamoxifen and ethynylestradiol (100 microM), respectively. Using rat fetal limb bones, ormeloxifene (100 microM) exhibited T/C ratio of 0.67, in comparison to 1.43 with PTH alone. Heat-killed bones exhibited negligible resorption (2.9%; T/C: 0.098) in response to PTH. In adult female rats, ormeloxifene (1.25 and 12.5 mg/kg per day) inhibited ovariectomy-induced increase in serum total and bone-specific alkaline phosphatase and osteocalcin and urine calcium/creatinine ratio to almost intact control level. Ovariectomy was accompanied by marked decrease in bone mineral density of isolated femur and tibia, being maximum in femur neck (28.3%; P < 0.01) and midshaft (23.7%; P < 0.01), but only marginal (6.7%; P > 0.05) in region proximal to tibio-fibular separation point. Decrease in BMD based on T-/Z-score, too, was >2.5 S.D. than mean value of normal young adult/age-matched females. This was prevented by ormeloxifene and the effect, though apparently more in females supplemented with higher dose of ormeloxifene, was not always significantly different and clear dose-response was not evident until BMD data was evaluated on T-/Z-score basis. The analysis also demonstrated much higher threshold level of tibia than femur and more so for their mid-shafts. Increase in BMD of isolated bones was also observed in ormeloxifene-treated intact females, without significantly altering biochemical markers of bone turnover or uterine weight. Findings suggest potential of ormeloxifene in management of post-menopausal osteoporosis and beneficial effect on BMD in women taking this SERM for contraception or any hormone-related clinical disorder.

Subcellular targeting domains of Abutilon mosaic geminivirus movement protein BC1.

Abutilon mosaic geminivirus (AbMV) encodes two movement proteins, BV1 and BC1, which mediate the intra- and intercellular transport of viral DNA in plants cooperatively. It has been shown previously that singly expressed BC1, fused to green fluorescent protein (GFP), accumulates preferentially either at the cell periphery or around the nucleus in separate plant cells. To define the BC1 domains responsible for understanding the subcellular sorting, deletion mutants were fused to GFP and expressed transiently in epidermal cells of non-host (Allium cepa) as well as of host (Nicotiana benthamiana) plants with basically the same results in both species. BC1-mediated intracellular sorting was dependent on two protein domains, an "anchor domain" (amino acids 117 to 180) which is necessary and sufficient to fix GFP:BC1 at the cell periphery and the nuclear environment, and a "pilot domain" (amino acids 1 to 49) in the absence of which the fusion proteins were found at both sites in the same cell simultaneously.

Interaction with anti-implantation and estrogen antagonistic activities of dl-ormeloxifene, a selective estrogen receptor modulator, by tetracycline in female Sprague-Dawley rats.

Among the 10 commonly used therapeutic agents investigated, concurrent oral administration of tetracycline (140 mg/kg) twice daily on Days 1-5 post-coitum (pc) interfered with the post-coital anti-implantation activity and almost completely abolished estrogen antagonistic activity of the single anti-implantation (1.5 mg/kg, orally) dose of dl-ormeloxifene administered on Day 1 pc, resulting in the occurrence of resorbed implantations in 50% of the females. However, no such interaction was evident when tetracycline was administered intramuscularly or when ormeloxifene was administered at twice its anti-implantation dose. There was no effect of ormeloxifene and/or tetracycline treatment on serum estradiol and progesterone levels, and all animals presented apparently normal corpora lutea. Ormeloxifene administered per se inhibited aminopyrine-N-demethylase (AD), glucose-6-phosphate dehydrogenase (G-6-PDH) and glutathione-S-transferase (GST) in the liver on the day of maximal endometrial receptivity, which was prevented by tetracycline co-administration. Aniline hydroxylase and AD were not detected in small intestine or uterus in vehicle control or any of the treatment groups. There was, however, no effect of ormeloxifene plus tetracycline treatment on serum total alkaline phosphatase activity. Findings suggest that interference with anti-implantation action of ormeloxifene by tetracycline might be due primarily to the almost complete abolition of its estrogen antagonistic activity at the uterine level, effected by decreased bioavailability of ormeloxifene and/or its active metabolite(s) by altered enterohepatic recirculation because of the effect on gut microflora. This might alternatively be related to an increased rate of its metabolism and elimination from the system via prevention of ormeloxifene-induced inhibition of hepatic AD, G-6-PDH, and GST, which, by effecting a decreased rate of metabolism, might be responsible for prolonged (approximately 120 h) duration of estrogen antagonistic/anti-implantation action of ormeloxifene in this species.

Quantitative analysis of agonist-dependent parathyroid hormone receptor trafficking in whole cells using a functional green fluorescent protein conjugate.

Many G-protein coupled receptors (GPCRs) undergo ligand-dependent internalization upon activation. The parathyroid hormone (PTH) receptor undergoes endocytosis following prolonged exposure to ligand although the ultimate fate of the receptor following internalization is largely unknown. To investigate compartmentalization of the PTH receptor, we have established a stable cell line expressing a PTH receptor-green fluorescent protein (PTHR-GFP) conjugate and an algorithm to quantify PTH receptor internalization. HEK 293 cells expressing the PTHR-GFP were compared with cells expressing the wild-type PTH receptor in whole-cell binding and functional assays. 125I-PTH binding studies revealed similar Bmax and kD values in cells expressing either the PTHR-GFP or the wild-type PTH receptor. PTH-induced cAMP accumulation was similar in both cell lines suggesting that addition of the GFP to the cytoplasmic tail of the PTH receptor does not alter the ligand binding or G-protein coupling properties of the receptor. Using confocal fluorescence microscopy, we demonstrated that PTH treatment of cells expressing the PTHR-GFP conjugate produced a time-dependent redistribution of the receptor to the endosomal compartment which was blocked by pretreatment with PTH antagonist peptides. Treatment with hypertonic sucrose prevented PTH-induced receptor internalization, suggesting that the PTH receptor internalizes via a clathrin-dependent mechanism. Moreover, co-localization with internalized transferrin showed that PTHR-GFP trafficking utilized the endocytic recycling compartment. Experiments using cycloheximide to inhibit protein synthesis demonstrated that recycling of the PTHR-GFP back to the plasma membrane was complete within 1-2 h of ligand removal and was partially blocked by pretreatment with cytochalasin D, but not nocodazole. We also demonstrated that the PTH receptor, upon recycling to the plasma membrane, is capable of undergoing a second round of internalization, a finding consistent with a role for receptor recycling in functional resensitization.

Impact of copper on biomonitoring enzyme ethoxyresorufin-o-deethylase in cultured catfish hepatocytes.

The enzyme ethoxyresorufin-o-deethylase (EROD) of the cytochrome P4501A family (CYP1A) in fish liver is increasingly being used as a molecular marker for qualitative and quantitative estimation of aquatic pollution throughout the world. The regulation and expression of this enzyme protein is very important from the toxicological point of view. The regulation of gene expression for this enzyme is mediated by the aromatic hydrocarbon receptor. In addition, cellular glutathione status influences expression of CYP1A. In this study, we explored the relationships among glutathione, EROD, and copper in cultured hepatocytes from Indian catfish. EROD activity in cultured hepatocytes was induced by carbofuran (CF), a widely used agricultural pesticide, and by beta-napthoflavone (BNF), a known inducer of CYP1A. Addition of copper into the culture media of hepatocytes inhibited EROD activity significantly. The activity of EROD elevated by CF and BNF was inhibited in hepatocytes pretreated with CF and BNF exposed to CuSO4. This effect was reflected in the glutathione status of the cells. The level of glutathione was increased by 3.4 and 3.0 times in hepatocytes treated with CF and BNF, respectively. These levels were inhibited in hepatocytes exposed to CuSO(4). Thus, copper interactions with glutathione may play a role in regulating EROD in hepatocytes.