Nicotinamide Adenine Dinucleotide Phosphate Dehydrogenase Research Articles

Saliva‑microbiome‑derived signatures: expected to become a potential biomarker for pulmonary nodules (MCEPN-1).

Oral microbiota imbalance is associated with the progression of various lung diseases, including lung cancer. Pulmonary nodules (PNs) are often considered a critical stage for the early detection of lung cancer; however, the relationship between oral microbiota and PNs remains unknown. We conducted a 'Microbiome with pulmonary nodule series study 1' (MCEPN-1) where we compared PN patients and healthy controls (HCs), aiming to identify differences in oral microbiota characteristics and discover potential microbiota biomarkers for non-invasive, radiation-free PNs diagnosis and warning in the future. We performed 16S rRNA amplicon sequencing on saliva samples from 173 PN patients and 40 HCs to compare the characteristics and functional changes in oral microbiota between the two groups. The random forest algorithm was used to identify PN salivary microbial markers. Biological functions and potential mechanisms of differential genes in saliva samples were preliminarily explored using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Cluster of Orthologous Groups (COG) analyses. The diversity of salivary microorganisms was higher in the PN group than in the HC group. Significant differences were noted in community composition and abundance of oral microorganisms between the two groups. Neisseria, Prevotella, Haemophilus and Actinomyces, Porphyromonas, Fusobacterium, 7M7x, Granulicatella and Selenomonas were the main differential genera between the PN and HC groups. Fusobacterium, Porphyromonas, Parvimonas, Peptostreptococcus and Haemophilus constituted the optimal marker sets (area under curve, AUC = 0.80), which can distinguish between patients with PNs and HCs. Further, the salivary microbiota composition was significantly correlated with age, sex, and smoking history (P < 0.001), but not with personal history of cancer (P > 0.05). Bioinformatics analysis of differential genes showed that patients with PN showed significant enrichment in protein/molecular functions related to immune deficiency and energy metabolisms, such as the cytoskeleton protein RodZ, nicotinamide adenine dinucleotide phosphate dehydrogenase (NADPH) dehydrogenase, major facilitator superfamily transporters and AraC family transcription regulators. Our study provides the first evidence that the salivary microbiota can serve as potential biomarkers for identifying PN. We observed a significant association between changes in the oral microbiota and PNs, indicating the potential of salivary microbiota as a new non-invasive biomarker for PNs. Clinical trial registration number: ChiCTR2200062140; Date of registration: 07/25/2022.

Targeting lncRNA NEAT1 hampers Alzheimer's disease progression.

Long noncoding RNA nuclear enriched abundant transcript 1 (lnc-NEAT1) is closely implicated in neurological diseases, while its implication in Alzheimer's disease (AD) is rarely reported. This study aimed to investigate the effect of lnc-NEAT1 knockdown on neuron injury, inflammation, and oxidative stress in AD, as well as its interaction with downstream targets and pathways. APPswe/PS1dE9 transgenic mice were injected with negative control or lnc-NEAT1 interference lentivirus. Besides, AD cellular model was constructed by amyloid β treatment in mice primary neuron cells; then, knockdown of lnc-NEAT1 and microRNA-193a was performed alone or in combination. In vivo experiments revealed that Lnc-NEAT1 knockdown improved cognition in AD mice reflected by Morrison water maze and Y-maze assays. Besides, lnc-NEAT1 knockdown reduced injury and apoptosis, decreased inflammatory cytokine levels, repressed oxidative stress level, and activated adenosine cyclophosphate response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) and nuclear factor erythroid 2-related factor 2 (NRF2)/nicotinamide adenine dinucleotide phosphate dehydrogenase 1 (NQO1) pathways in hippocampi of AD mice. Notably, lnc-NEAT1 down-regulated microRNA-193a both in vitro and in vivo and acted as a decoy of microRNA-193a. In vitro experiments showed that lnc-NEAT1 knockdown decreased apoptosis and oxidative stress, improved cell viability, also activated CREB/BDNF and NRF2/NQO1 pathways in AD cellular model. Meanwhile, microRNA-193a knockdown showed the opposite effects, which also attenuated lnc-NEAT1 knockdown-mediated reduction in injury, oxidative stress, and CREB/BDNF and NRF2/NQO1 pathways of AD cellular model. In conclusion, lnc-NEAT1 knockdown reduces neuron injury, inflammation, and oxidative stress through activating microRNA-193a mediated CREB/BDNF and NRF2/NQO1 pathways in AD.

Chemoprevention of Prostate Cancer Cells by Vitamin C plus Quercetin: role of Nrf2 in Inducing Oxidative Stress

To assess the effect of sequential treatment with Vitamin C (VC) and Quercetin (Q) on Nrf2-related oxidative stress in PC3 and DU145 cells, viability was measured by MTT assay. Intracellular ROS levels were determined, using 2'-7'-dichlorodihydrofluorescein diacetate fluorescent as a probe. Nrf2 gene expression was investigated by quantitative reverse transcription polymerase chain reaction, and Nrf2 protein levels were defined by western blot analysis. The activity of glutathione peroxidase (GPx), glutathione reductase (GR), nicotinamide adenine dinucleotide phosphate dehydrogenase quinone 1 (NQO1) and hemeoxygenase 1 (HO-1) enzymes were measured. The IC50 values for VC + Q were 263.03–372.1 µM and 144.2–194.1 µM respectively and 200 µM VC + 50 µM Q (dose no.1) and 100 µM VC + 75 µM Q (dose no.2) were selected. Sequential treatment of PC3 cells led to a significant reduction of Nrf2 mRNA expression and protein levels in addition to a significant reduction of GPx, GR and NQO1 enzymatic activity. Although the data was slightly different for DU145 cells after the treatments, in terms of Nrf2 gene expression, we obtained the same results. Our study revealed the significant effects of sequential treatment with VC + Q on Nrf2 suppression in prostate cancer cells.

Idebenone Protects against Acute Murine Colitis via Antioxidant and Anti-Inflammatory Mechanisms.

Oxidative stress is a key player of the inflammatory cascade responsible for the initiation of ulcerative colitis (UC). Although the short chain quinone idebenone is considered a potent antioxidant and a mitochondrial electron donor, emerging evidence suggests that idebenone also displays anti-inflammatory activity. This study evaluated the impact of idebenone in the widely used dextran sodium sulphate (DSS)-induced mouse model of acute colitis. Acute colitis was induced in C57BL/6J mice via continuous exposure to 2.5% DSS over 7 days. Idebenone was co-administered orally at a dose of 200 mg/kg body weight. Idebenone significantly prevented body weight loss and improved the disease activity index (DAI), colon length, and histopathological score. Consistent with its reported antioxidant function, idebenone significantly reduced the colonic levels of malondialdehyde (MDA) and nitric oxide (NO), and increased the expression of the redox factor NAD(P)H (nicotinamide adenine dinucleotide phosphate) dehydrogenase quinone-1 (NQO-1) in DSS-exposed mice. Immunohistochemistry revealed a significantly increased expression of tight junction proteins, which protect and maintain paracellular intestinal permeability. In support of an anti-inflammatory activity, idebenone significantly attenuated the elevated levels of pro-inflammatory cytokines in colon tissue. These results suggest that idebenone could represent a promising therapeutic strategy to interfere with disease pathology in UC by simultaneously inducing antioxidative and anti-inflammatory pathways.

Batryticatus Bombyx Protects Dopaminergic Neurons Against MPTP-Induced Neurotoxicity by Inhibiting Oxidative Damage.

Oxidative stress plays an important role in the degeneration of dopaminergic neurons in Parkinson’s disease (PD). Altered redox homeostasis in neurons interferes with several biological processes, ultimately leading to neuronal death. Oxidative damage has been identified as one of the principal mechanisms underlying the progression of PD. Several studies highlight the key role of superoxide radicals in inducing neuronal toxicity. Batryticatus Bombyx (BB), the dried larva of Bombyx mori L. infected by Beauveria bassiana (Bals.) Vuill., has been used in traditional medicine for its various pharmacological effects. In the present study, BB showed a beneficial effect on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity by directly targeting dopaminergic neurons. Treatment with BB improved behavioral impairments, protected dopaminergic neurons, and maintained dopamine levels in PD mouse models. Here, we investigated the protective effects of BB on MPTP-induced PD in mice and explored the underlying mechanisms of action, focusing on oxidative signaling. In MPTP-induced PD, BB promoted recovery from impaired movement, prevented dopamine depletion, and protected against dopaminergic neuronal degradation in the substantia nigra pars compacta (SNpc) or the striatum (ST). Moreover, BB upregulated mediators of antioxidative response such as superoxidase dismutase (SOD), catalase (CAT), glutathione (GSH), Heme oxygenase 1 (HO-1), and NAD(P)H (nicotinamide adenine dinucleotide phosphate) dehydrogenase (NQO1). Thus, treatment with BB reduced the oxidative stress, improved behavioral impairments, and protected against dopamine depletion in MPTP-induced toxicity.

Effect of the Lipid Peroxidation Product 4-Hydroxynonenal on Neuroinflammation in Microglial Cells: Protective Role of Quercetin and Monochloropivaloylquercetin

The lipid peroxidation-derived aldehyde 4-hydroxynonenal (HNE) has been implicated in a number of oxidative stress-induced inflammatory pathologies such as neurodegenerative diseases and aging. In this regard, we investigated the effects of HNE on neuroinflammatory responses by measuring cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) induction with cytokine production. In addition, we measured nuclear factor erythroid 2-related factor 2 (Nrf-2)/Kelch-like ECH-associated protein 1 (Keap1) signaling proteins, and antioxidant enzymes heme oxygenase-1 (HO-1) and nicotinamide adenine dinucleotide phosphate dehydrogenase, quinone 1 (NQO1), and compared the results with quercetin and monochloropivaloylquercetin (MPQ) pretreated microglial cells. Cytotoxicity was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and production of cytokines was determined by cytokine array. Furthermore, intracellular Nfr2/Keap1 signaling proteins, HO-1, NQO1, and COX-2 expression were analyzed by western blot in 2.5 μM HNE treated BV-2 cells. Inducible nitric oxide synthase (iNOS) and COX-2 mRNA levels were measured with reverse transcription-quantitative polymerase chain reaction. HNE induced both COX-2 mRNA and protein levels, iNOS mRNA expression, and cytokine production. In addition, HNE markedly increased Keap1 levels and decreased cytoplasmic Nrf-2 expression with antioxidant enzyme HO-1 levels. Quercetin and monochloropivaloylquercetin treatment alleviated neuroinflammatory responses in microglial cells, by decreasing COX-2 mRNA expression. Monochloropivaloylquercetin decreased cytoplasmic Keap1 levels and increased nuclear translocation of Nrf-2 resulted in induction of HO-1 and NQO1 expression. These results suggest that HNE could be a link between oxidative stress and inflammation in BV-2 microglia cells. In particular, monochloropivaloylquercetin alleviated inflammation, probably by decreasing the expression of proinflammatory genes and strengthening the antioxidant defense system.

The role of quercetin and vitamin C in Nrf2-dependent oxidative stress production in breast cancer cells.

The balance between the production and elimination of reactive oxygen species (ROS) is essential in determining whether cells survive or undergo apoptosis. Nuclear factor erythroid 2-related factor 2 (Nrf2) may act as a sensor for electrophilic stress, thus regulating the intracellular antioxidant response. The present study investigated the role of vitamin C (VC) and quercetin (Q) in the induction of Nrf2-mediated oxidative stress in cancer cells. An MTT assay was conducted to examine the anti-proliferative effects of VC and Q. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were performed to determine the messenger RNA (mRNA) and protein expression of Nrf2, respectively. The activity of nicotinamide adenine dinucleotide phosphate dehydrogenase quinone 1, heme oxygenase 1, glutathione peroxidase, glutathione reductase and reduced glutathione were measured by spectrophotometric analysis. Intracellular generation of ROS was determined using 2'-7'-dichlorodihydrofluorescein diacetate fluorescent probes. The results demonstrated that the cytotoxicity (50% inhibitory concentration) of VC and Q were 271.6-480.1 and 155.1-232.9 µM, respectively. Additionally, there was a significant decrease in the expression of Nrf2 mRNA and protein levels following the treatment of breast cancer cells with VC and Q (P=0.024). Following treatment with VC and Q, the nuclear/cytosolic Nrf2 ratio was reduced by 1.7-fold in MDA-MB 231 cells, 2-fold in MDA-MB 468 cells, 1.4-fold in MCF-7 cells and 1.2 fold in A549 cells. Sequential treatment with VC and Q decreased endogenous production of ROS in a dose-dependent manner (P=0.027). The results of the current study suggest that VC and Q treatment may be developed as an adjuvant for patients with cancer and overexpression of Nrf2.

Lutein alleviates arsenic-induced reproductive toxicity in male mice via Nrf2 signaling.

This study aims to investigate the mechanisms involved in the action of lutein (LU) alleviating arsenic-induced reproductive toxicity using mice model. Forty male Kunming mice were received following treatments by gavage: normal saline solution (control), arsenic trioxide (ATO; 5 mg/kg/day), LU (40 mg/kg/day), and ATO + LU (5 mg/kg/day + 40 mg/kg/day). At the end, the mice were killed by cervical dislocation and weighed. Pathological examination was done on the testis. The biomedical parameters including superoxide dismutase (SOD), glutathione (GSH), total antioxidative capability, malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and reproductive indexes were analyzed. The messenger RNA (mRNA) and protein expression of Nrf2, heme oxygenase 1 (HO-1), glutathione S-transferase (GST), nicotinamide adenine dinucleotide phosphate dehydrogenase, quinone 1 (NQO1) in testis were detected by real-time polymerase chain reaction and Western blot. We found that there was a decrease in sperm count; testis somatic index; the activities of SOD, GSH, total antioxidative capacity (p < 0.01, respectively) in ATO-treated mice, while there was an increase in the levels of sperm abnormalities, MDA, and 8-OHdG than control (p < 0.01, respectively). The groups treated with ATO + LU showed recovery of the measured parameters between those of ATO or saline-treated group. The antagonized interaction between ATO and LU was statistically significant (p < 0.01). Mice treated with ATO + LU also showed greater mRNA expression of Nrf2, HO-1, NQO1, and GST than ATO or saline-treated groups. These findings suggest that LU alleviates reproductive toxicity induced by arsenic in male mice via Nrf2 signaling, which implicates a possible mechanism of LU in preventing the reproductive injury, and elucidates that consuming the rich plant sources of LU will alleviate the reproductive toxicity induced by chemicals.

Low-dose carvedilol protects against acute septic renal injury in rats during the early and late phases.

Recent findings from septic acute renal injury studies have implicated the mitochondrion as an important factor in kidney injury, and that increased sympathetic nerve activity may contribute to the induction of organ failure. This study investigated the impact of a nondepressor dose of carvedilol, which is a beta-adrenoreceptor antagonist with antioxidant activity, on septic renal injury induced in rats with cecal ligation and puncture (CLP). Three groups of rats were studied. The first group was the sham-operated control. The other 2 groups of rats underwent CLP, and were administered either the vehicle or carvedilol (2.0 mg/kg body mass, by intraperitoneal (i.p.) injection, daily for 2 days as well as 30 min prior to CLP). Kidney function, inflammatory parameters, mitochondrial function, and renal perfusion pressure (RPP) were investigated at 6 and 18 h after CLP. Carvedilol did not significantly induce hypotension, and it significantly improved RPP and renal dysfunction induced with CLP, together with significant reductions in serum levels of interleukin 6 and tumor necrosis factor-alpha. Septic kidney injury mediated increased levels of malondialdehyde and protein carbonyls. Carvedilol also attenuated the decrease in kidney mitochondrial glutathione and nicotinamide adenine dinucleotide phosphate dehydrogenase. Further, intracellular renal edema and inflammation induced with CLP were reduced with carvedilol. These findings suggest renoprotective effects of carvedilol in sepsis.

Mitochondria: a pathogenic paradigm in hypertensive renal disease.

Mitochondria were first described in 1840 as bioblasts, elementary organisms responsible for vital cellular functions, but were subsequently named mitochondria, from the Greek names mitos (thread) and chondros (granule), which describes their appearance during spermatogenesis.1 Their discovery generated substantial interest given their structure resembling bacteria, which led in subsequent years to important scientific discoveries positioning mitochondria as the energy powerhouse of the cell. The unique architecture of mitochondria, consisting of 2 membranes (outer and inner) and compartments (intermembrane space and matrix), is crucial for their vital functions. Mitochondria serve not only as primary sources of cellular energy, but also modulate several cellular processes, including oxidative phosphorylation, calcium homeostasis, thermogenesis, oxygen sensing, proliferation, and apoptosis.2 Therefore, mitochondrial injury and dysfunction might be implicated in the pathogenesis of several diseases. Hypertension accounts for nearly 30% of patients reaching end-stage renal disease.3 Renal injury secondary to hypertension or to ischemia associated with renovascular hypertension (distal to renal artery stenosis) may have significant and detrimental effect on health outcomes. Studies have highlighted several deleterious pathways, including inflammation, oxidative stress, and fibrosis that are activated in the hypertensive kidney, eliciting functional decline.4,5 However, the precise molecular mechanisms responsible for renal injury have not been fully elucidated. Over the past few years, increasing evidence has established the experimental foundations linking mitochondrial alterations to hypertensive renal injury (Table). Mitochondriopathies, abnormalities of energy metabolism secondary to sporadic or inherited mutations in nuclear or mitochondrial DNA (mtDNA) genes, may contribute to the development and progression of hypertension and its complications. In addition, several studies have reported mitochondrial damage and dysfunction consequent to hypertensive renal disease. View this table: Table. Evidence of Renal Mitochondrial Damage in Models of Hypertension and Antihypertensive Treatment Importantly, hypertensive-induced renal injury is characterized by activation of several deleterious pathways, including oxidative stress, renin–angiotensin–aldosterone …

Chronic hypoxia increases rat diaphragm muscle endurance and sodium-potassium ATPase pump content

The effects of chronic hypoxia (CH) on respiratory muscle are poorly understood. The aim of the present study was to examine the effects of CH on respiratory muscle structure and function, and to determine whether nitric oxide is implicated in respiratory muscle adaptation to CH. Male Wistar rats were exposed to CH for 1-6 weeks. Sternohyoid and diaphragm muscle contractile properties, muscle fibre type and size, the density of fibres expressing sarco/endoplasmic reticulum calcium-ATPase (SERCA) 2 and sodium-potassium ATPase (Na+,K+-ATPase) pump content were determined. Muscle succinate dehydrogenase (SDH) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) dehydrogenase activities were also assessed. Acute and chronic blockade of nitric oxide synthase (NOS) was employed to determine whether or not NO is critically involved in functional remodelling in CH muscles. CH improved diaphragm, but not sternohyoid, fatigue tolerance in a time-dependent fashion. This adaptation was not attributable to increased SDH or NADPH dehydrogenase activities. The areal density of muscle fibres and relative area of fibres expressing SERCA2 were unchanged. Na+,K+-ATPase pump content was significantly increased in CH diaphragm. Chronic NOS inhibition decreased diaphragm Na+,K+-ATPase pump content and prevented CH-induced increase in muscle endurance. This study provides novel insight into the mechanisms involved in CH-induced muscle plasticity. The results may be of relevance to respiratory disorders characterised by CH, such as chronic obstructive pulmonary disease.

Iron and Parenteral Nutrition

There is ample evidence that iron is an essential trace element, but assessment of iron status and decisions on the amounts needed and the means of delivery in patients on parenteral nutrition (PN) have been unclear. Although iron requirements may diminish during acute illness, the frequent concurrence of blood loss and iron deficiency argue strongly for maintenance of levels of delivery in line with basal requirements. Maintenance of iron delivery has not been thought likely to present risk, but new data are questioning this. The needs of menstruating, pregnant, and lactating women are greater than those of adult men. The evidence favors an intravenous dose of around 1 mg of elemental iron per day in adult men and postmenopausal women. Doses of 1.5 mg/d [DOSAGE ERROR CORRECTED] in menstruating women and 2.0 mg/d [DOSAGE ERROR CORRECTED] for those in the later stages of pregnancy or lactating can be supported. A calibrated response is required in the growing child. Continued monitoring of iron status is recommended. Iron is an essential component for most PN regimens. The quantity of iron to be included should take account of predicted requirements.

Monoamine Oxidase-B Mediates Ecstasy-Induced Neurotoxic Effects to Adolescent Rat Brain Mitochondria

3,4-Methylenedioxymethamphetamine (MDMA)-induced neurotoxicity and the protective role of monoamine oxidase-B (MAO-B) inhibition were evaluated at the mitochondrial level in various regions of the adolescent rat brain. Four groups of adolescent male Wistar rats were used: (1) saline control, (2) exposed to MDMA (4 x 10 mg/kg, i.p.; two hourly), (3) treated with selegiline (2 mg/kg, i.p.) 30 min before the same dosing of MDMA, and (4) treated with selegiline (2 mg/kg, i.p.). Body temperatures were monitored throughout the whole experiment. Animals were killed 2 weeks later, and mitochondria were isolated from several brain regions. Our results showed that "binge" MDMA administration causes, along with sustained hyperthermia, long-term alterations in brain mitochondria as evidenced by increased levels of lipid peroxides and protein carbonyls. Additionally, analysis of mitochondrial DNA (mtDNA) revealed that NDI nicotinamide adenine dinucleotide phosphate dehydrogenase subunit I and NDII (nicotinamide adenine dinucleotide phosphate dehydrogenase subunit II) subunits of mitochondrial complex I and cytochrome c oxidase subunit I of complex IV suffered deletions in MDMA-exposed animals. Inhibition of MAO-B by selegiline did not reduce hyperthermia but reversed MDMA-induced effects in the oxidative stress markers, mtDNA, and related protein expression. These results indicate that monoamine oxidation by MAO-B with subsequent mitochondrial damage may be an important contributing factor for MDMA-induced neurotoxicity.

RECOGNITION OF A NOVEL MELANOTIC MUTANT IN A FIELD POPULATION OF CULEX PIPIENS QUINQUEFASCIATUS IN SOUTHERN ZAMBIA

Genetic mutations controlling eye color, fat body color, structural abnormalities, and insecticide resistance are common in mosquitoes. We have identified a novel color variant of Culex pipiens quinquefasciatus characterized by a heavily pigmented integument in adult specimens circulating in field populations of this species in southern Zambia. Mosquitoes were collected monthly by pyrethrum spray catch between November and May 2004-05 and 2005-06, with between 25% and 80% of the total Cx. p. quinquefasciatus collections comprising this pigmented variety. The identity of pigmented specimens was morphologically confirmed as Cx. p. quinquefasciatus by examination of orientation of the dorsal and ventral arms of the male genitalia of F1 male progeny reared in the laboratory, and molecularly verified by diagnostic polymerase chain reaction and nicotinamide adenine dinucleotide phosphate dehydrogenase subunit 4 nucleotide sequence homology. Preliminary laboratory rearings indicated that the pigmentation was heritable and not influenced by larval habitat and environmental conditions. Further investigation into the mechanism of the mutation, inheritance patterns, and potential linkage to additional markers is pending.

Morphofunctional Evidence of Changes in Principal and Mitochondria-Rich Cells in the Epidermis of the Frog Rana kl. esculenta Living in a Polluted Habitat

The epidermis of vertebrates is the body's principal barrier against environment and its possible contaminants. The presence of keratins, as well as specific detoxifying molecules or enzyme activities, in the various epidermis layers is believed to be involved in providing protection from harmful environmental influences. Anuran integument is poorly hornified and thus permeable to some endogenous and exogenous compounds and thus serves as a good bioindicator of overall environmental conditions. In the present investigation, we studied the epidermis of Rana kl. esculenta adult specimens collected at two different rice fields, relatively unpolluted and heavily polluted, respectively. Environmental pollution was assayed by chemical analysis performed on both sediments and animals. We evaluated the structural aspects of the epidermis at both light and electron microscopy levels and the pattern of keratinization by immunohistochemistry. Furthermore, we studied the activities of some enzymes (acid and alkaline phosphatase, nitric oxide synthase-related nicotinamide adenine dinucleotide phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, catalase, nonspecific esterases, and succinic dehydrogenase) involved mainly in membrane transport, xenobiotics, and oxidative metabolism. Compared with controls, in polluted animals we found the following results: (1) an increase in pollutant levels (i.e., cadmium, mercury, and lead); (2) less keratinized superficial cells in the epidermis; and (3) changes in most enzyme activities in keratinocytes and mitochondria-rich cells (particularly glucose-6-phosphate dehydrogenase and esterases, both important to counteract oxidative and toxic stress). Taken as a whole, the present data indicate the morphofunctional plasticity of the frog epidermis in response to environmental contamination.

Arsenic trioxide (AT) is a novel human neutrophil pro‐apoptotic agent: effects of catalase on AT‐induced apoptosis, degradation of cytoskeletal proteins and de novo protein synthesis

The anti-cancer drug arsenic trioxide (AT) induces apoptosis in a variety of transformed or proliferating cells. However, little is known regarding its ability to induce apoptosis in terminally differentiated cells, such as neutrophils. Because neutropenia has been reported in some cancer patients after AT treatment, we hypothesised that AT could induce neutrophil apoptosis, an issue that has never been investigated. Herein, we found that AT-induced neutrophil apoptosis and gelsolin degradation via caspases. AT did not increase neutrophil superoxide production and did not induce mitochondrial generation of reactive oxygen species. AT-induced apoptosis in PLB-985 and X-linked chronic granulomatous disease (CGD) cells (PLB-985 cells deficient in gp91(phox) mimicking CGD) at the same potency. Addition of catalase, an inhibitor of H2O2, reversed AT-induced apoptosis and degradation of the cytoskeletal proteins gelsolin, alpha-tubulin and lamin B1. Unexpectedly, AT-induced de novo protein synthesis, which was reversed by catalase. Cycloheximide partially reversed AT-induced apoptosis. We conclude that AT induces neutrophil apoptosis by a caspase-dependent mechanism and via de novo protein synthesis. H2O2 is of major importance in AT-induced neutrophil apoptosis but its production does not originate from nicotinamide adenine dinucleotide phosphate dehydrogenase activation and mitochondria. Cytoskeletal structures other than microtubules can now be considered as novel targets of AT.

Histochemical Demonstration of the Alterations in the Renal Dehydrogenases Activities Induced by Lead in Wistar Albino Rats (Rattus norvegicus).

A total of 112 male albino rats (Rattus norvegicus) were divided into seven groups and exposed to lead acetate trihydrate (0, 0.125, 0.25, 0.5, 1.0, 2.0 and 4 per cent for 1 to 8 months) in drinking water to investigate possible histochemical changes of nine renal dehydrogenases due to lead intoxication. A marked increase in the activity of lactate-, glucose-6-phosphate-, α-glycerophosphate-, reduced nicotinamide adenine dinucleotide (NAD)- and reduced nicotinamide adenine dinucleotide phosphate (NADP) dehydrogenase was observed while significant reduction was recorded in the activity of succinate-, malate-, isocitrate- and glutamate dehydrogenase. Changes in the activity of renal dehydrogenases were seen mainly in the pars recta and to a lesser extent in the pars convoluta and the ascending thick segment of the loop of Henle while the other medullary portions of the renal tubule were less affected. These histochemical findings led us to conclude that such changes in the renal dehydrogenases activities were due to chronic lead exposure and could be an adaptation to the metabolic, structural and functional alterations in the organelles of the renal cells especially the mitochondria.

Elucidation of Schistosoma japonicum population dynamics in pigs using PCR-based identification of individuals representing distinct cohorts

The study reported here investigated the interactions of successive infections and acquired resistance of pigs to challenge infections of Schistosoma japonicum. Two morphologically indistinguishable geographical isolates from China (from Anhui and Zhejiang provinces) were used for the infections. The worms of the two isolates were distinguishable by PCR-linked restriction fragment length polymorphism analysis of the nicotinamide adenine dinucleotide phosphate dehydrogenase I gene of the mitochondrial genome. Thirty-two pigs divided into seven groups were used in the experiment. Two groups received a single infection by either the Anhui or the Zhejiang isolate. In Challenge Groups 1, 4, 6, 8 and 12, a primary infection of the Zhejiang isolate was followed by a challenge infection with the Anhui isolate at week 1, 4, 6, 8 or 12 after the primary infection. In this way it was possible to determine whether worms recovered by perfusion originated from the primary or the challenge infection. Only the challenge infection at week 1 resulted in a higher worm burden when compared with a single primary infection with the Zhejiang isolate. The results showed that challenge worms were able to establish, and that the proportion of worms originating from challenge infection increased at the later challenge infections, however without an increase in the total number of worms. In addition, mixed pairs of the two isolates were found in all challenge-infected groups. The results indicate that pigs are able to mount a partial resistance against re-infection with S. japonicum by 4 weeks after a primary infection, but that worms of the challenge infections eventually replace the primary infection. The finding of mixed pairs of the two isolates indicates that worms of S. japonicum are either polygamous or able to wait in solitude for up to 12 weeks for a partner.

Adaptative changes of metabolic zonation during the development of cirrhosis in growing rats

To evaluate changes in liver metabolic zonation during development of juvenile cirrhosis, zonal activities of succinate dehydrogenase, glutamate dehydrogenase, glucose-6-phosphatase, and nicotinamide adenine dinucleotide phosphate (NADPH) dehydrogenase were measured by quantitative cytochemistry in the liver of developing rats intoxicated with carbon tetrachloride and phenobarbitone. During treatment, activities were most decreased in perivenular zones and subsequently at the periphery of the cirrhotic nodules for succinate dehydrogenase and glucose-6-phosphatase, whereas glutamate dehydrogenase and NADPH dehydrogenase were less affected. In the periportal zones, enzyme activities decreased less. After stopping intoxication, the rats remained cirrhotic, but enzyme activities returned to control perivenular levels at the periphery of the cirrhotic nodule and to control periportal levels at its center. It is concluded that a metabolic zonation persists in carbontetrachloride/phenobarbitone-induced juvenile cirrhosis and that enzyme activities can recover despite persisting cirrhosis. In this model, afferent vessels seem to be located at the center of the cirrhotic nodules, and efferent vessels, at their periphery. A different metabolic zonation may exist in other human and animal liver cirrhosis that could be related to the site of initial liver damage.

The metabolite ratio as a function of chloral hydrate dose and intracellular redox state in the perfused rat liver.

Chloral hydrate (CH), an intermediate metabolite of trichloroethylene, is reduced to trichloroethanol (TCE) by alcohol dehydrogenase and aldehyde reductase, and is also oxidized to trichloroacetic acid (TCA) by the nicotinamide adenine dinucleotide (NAD)-dependent enzyme, CH dehydrogenase. Alcohol dehydrogenase requires reduced NAD (NADH), aldehyde reductase requires reduced nicotinamide adenine dinucleotide phosphate (NADPH) and CH dehydrogenase requires NAD to complete the reaction. It is unclear which reaction is predominant at the physiological redox level in intact liver cells. To study this question, we perfused the livers of well-fed rats with Krebs-Ringer buffer solution containing 0.1 mM pyruvate/1.0 mM lactate. The levels of TCE and TCA in the effluent were measured by gas chromatography, and the fluorescence of reduced pyridine nucleotides was measured with a surface fluorometer. When a low concentration (below 0.25 mM) of CH was administered, more TCA than TCE was produced. When a high concentration of CH was administered (over 0.5 mM), TCE production was greater. Reduced pyridine nucleotides decreased inversely with the CH concentration. Even at low CH concentrations, pyridine nucleotides were not reduced. When 10 mM lactate was added to the perfusate in order to reduce the pyridine nucleotides in the liver cells, the TCE/TCA ratio increased. On the other hand, the TCE/TCA ratio tended to fall following the addition of 5.0 mM pyruvate. In conclusion, the TCE/TCA ratio was altered according to the concentration of CH, and to the redox level of pyridine nucleotides in the liver.