Ameliorative effect of naringenin on hyperglycemia-mediated inflammation in hepatic and pancreatic tissues of Wistar rats with streptozotocin- nicotinamide-induced experimental diabetes mellitus

In diabetes mellitus (DM), sustained hyperglycemia results in the generation of reactive oxygen species, ultimately leading to increased oxidative stress and inflammation in vital tissues. In the present study, possible ameliorative effects of naringenin on hyperglycemia-mediated inflammation in experimental streptozocin (STZ)-nicotinamide-induced DM were sought. DM was induced experimentally in overnight-fasted Wistar rats (150-180 g) by intra-peritoneal injection of STZ (50 mg/kg.b.w) and of nicotinamide (110 mg/kg.b.w); control rats (n = 6) received only vehicle (0.5 ml of 0.1 M of cold citrate buffer; pH 4.5). One group of diabetic rats (n = 6) was left untreated while another group of diabetic rats (n = 6) received naringenin (50 mg/kg b.w./day) orally for 21 days. At this time, hemotological indices (erythrocyte sedimentation rate [ESR], total white blood cell [WBC] count, differential WBC percentage, and platelet count) were measured. Significant alterations in expression of gene and protein biomarkers of inflammation in hepatic and pancreatic tissues were determined by measuring mRNA levels and the level of protein expressed, respectively, as was the total nitric oxide level in these tissues. Diabetic rats showed significantly higher mean ESR values, total WBC counts, differential WBC percentages, and platelet counts than those in control rats; similarly, mean mRNA levels of C-reactive protein, pro-inflammatory cytokine, nuclear factor-κB and inducible nitric oxide synthase genes and mean intensities of expression of the corresponding proteins in the hepatic and pancreatic tissue samples from diabetic rats significantly exceeded those in control rats. However, in diabetic rats treated with naringenin, the values of hematological, mRNA transcript and protein indices of inflammation were all lower than those in diabetic rats. These results suggest that naringenin possibly alleviates hyperglycemia-mediated inflammation in experimental STZ-nicotinamide-induced DM in Wistar rats.

PCR for the molecular diagnosis of mycotic keratitis

Mycotic keratitis, an infection of the cornea caused by fungi, is a medical emergency, with patients presenting with considerable pain and distress. For effective management of the condition, a specific diagnosis must be made rapidly to permit early initiation of antifungal therapy. Currently, direct microscopic examination and culture of corneal material constitute the 'gold standard' for diagnosis. However, rapid, sensitive yet specific tests are needed to detect a small number of, or nonviable, fungi. PCR has many potential advantages when used as a diagnostic aid for mycotic keratitis; the present review covers these advantages, and possible limitations. An expert assessment is also made of studies that have used PCR for the diagnosis of mycotic keratitis. The review concludes with a Five-year view of the potential impact of PCR in management of mycotic keratitis.

Antihypercholesterolemic and antioxidative effects of an extract of the oyster mushroom, Pleurotus ostreatus, and its major constituent, chrysin, in Triton WR-1339-induced hypercholesterolemic rats

Hypercholesterolemia and oxidative stress are known to accelerate coronary artery disease and progression of atherosclerotic lesions. In the present study, an attempt was made to evaluate the putative antihypercholesterolemic and antioxidative effects of an ethanolic extract of the oyster mushroom (Pleurotus ostreatus) and chrysin, one of its major components, in hypercholesterolemic rats. Hypercholesterolemia was induced in rats by a single intraperitoneal injection of Triton WR-1339 (300 mg/kg body weight (b.wt.)), which resulted in persistently elevated blood/serum levels of glucose, lipid profile parameters (total cholesterol, triglycerides, low-density lipoprotein-, and very low-density lipoprotein-cholesterol), and of hepatic marker enzymes (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase). In addition, lowered mean activities of hepatic antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) and lowered mean levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) were observed. Oral administration of the mushroom extract (500 mg/kg b.wt.) and chrysin (200 mg/kg b.wt.) to hypercholesterolemic rats for 7 days resulted in a significant decrease in mean blood/serum levels of glucose, lipid profile parameters, and hepatic marker enzymes and a concomitant increase in enzymatic and nonenzymatic antioxidant parameters. The hypercholesterolemia-ameliorating effect was more pronounced in chrysin-treated rats than in extract-treated rats, being almost as effective as that of the standard lipid-lowering drug, lovastatin (10 mg/kg b.wt.). These results suggest that chrysin, a major component of the oyster mushroom extract, may protect against the hypercholesterolemia and elevated serum hepatic marker enzyme levels induced in rats injected with Triton WR-1339.

Protective role of chrysin against oxidative stress in d-galactose-induced aging in an experimental rat model

AIM

To evaluate the putative protective role of chrysin, an isoflavone, on D-galactose-induced aging in an experimental rat model.

METHODS

Rats were divided into five groups of five each. Group I received 0.9% saline only. Groups II, III and IV received d-galactose (50 mg/kg bodyweight) intraperitoneally, additionally group III and group IV received chrysin (20 mg/kg bodyweight) and α-tocopherol acetate (200 mg/kg bodyweight), respectively. Group V received chrysin alone. The experiment period was for a period of 8 weeks. After the rats were killed, the tissue samples were analyzed for mean activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, glucose-6-phosphate dehydrogenase, reduced glutathione, vitamin C, vitamin E, malondialdehyde and protein carbonyl. Histopathological studies were also carried out for morphological conformation.

RESULTS

Tissue samples from D-galactose-exposed untreated rats showed significantly (P < 0.05) lower levels of enzymatic and non-enzymatic anti-oxidants, and significantly (P < 0.05) higher levels of malondialdehyde and protein carbonyl when compared with group I and group III rats. Oral administration of chrysin for a period of 8 weeks, concomitant with the exposure to D-galactose, appeared to protect against oxidative damage and maintained all parameters at near normal levels. Histopathological studies confirmed the oxidative damage caused by D-galactose alone in tissues and also showed the tissue protective role of chrysin in rats receiving D-galactose and chrysin.

CONCLUSION

These results suggest that chrysin protects against oxidative stress-induced tissue damage in D-galactose-induced aging in an experimental rat model.

Glutathione S-transferase and metallothionein levels in the freshwater prawn Macrobrachium malcolmsonhi exposed to mercury

Healthy juveniles of M. malcolmsoniiwere exposed to 24.1 microg l(-1) of mercury (96 hr LC50: 145 microg l(-1) Hg) for a period of 21 days. The hepatopancreas and gills of the prawns were sampled on 8th, 15th and 22nd day of exposure. Accumulation and elimination of Hg, activity of glutathione S-transferase (GST), content of glutathione (GSH) and metallothionein (MT) level were studied. Mercury accumulation was found to be higher in the hepatopancreas (88.60 microg g(-1)) and lower in the gills (67.8 microg g(-1)). However, Hg elimination was found to be faster in the gills (62%) and slower in the hepatopancreas (58%). Therefore, the rate of Hg elimination did not match the rate of its uptake. The activity of GST was found to be higher in tissues of test prawns (5.94-9.13 nmol mg(-1) protein min(-1)) on all sampling days when compared with controls (3.454.23 nmol mg(-1) protein min(-1)). Similarly, the content of GSH was found to be higher in tissues of test prawns (0.80-1.43 micromol g(-1) protein) on all sampling days when compared with controls (0.55-1.00 micromol g(-1) protein). These results indicate the formation of glutathione conjugate in test prawns to eliminate Hg. The induction of MT level was also found to be higher in tissues of test prawns (57.50-75.76 nmol g(-1) protein) on all sampling days when compared with control (20.24-45.22 nmol g(-1) protein). This indicates the fact that sequestration of Hg has occurred for its easy elimination. Thus, induction of GST-GSH and MT ensured protection and adaptation of test prawns to thrive in Hg contaminated environment.

Prevention of selenite-induced cataractogenesis by an ethanolic extract of Cineraria maritima: an experimental evaluation of the traditional eye medication

In the present study, the antioxidant potential of an ethanolic extract of Cineraria maritima and its efficacy in preventing selenite-induced cataractogenesis were assessed in vitro and in vivo. In the in vitro phase of the study, lenses dissected out from the eyes of Wistar rats were incubated for 24 h at 37 °C in Dulbecco's modified Eagle medium (DMEM) alone (group I), in DMEM containing 100 μM of selenite only (group II), or in DMEM containing 100 μM of selenite and 300 μg/ml C. maritima extract added at the same time (group III). Gross morphological examination of the lenses revealed dense opacification in group II, minimal opacification in group III, and no opacification in group I lenses. The mean activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase were significantly lower in group II than in group I or group III lenses, while malondialdehyde concentration was significantly higher in group II lenses than in group I and group III lenses. In the in vivo phase of the study, dense opacification of lenses was noted in all rat pups (100%) that had received a single subcutaneous injection of sodium selenite alone (19 μM/kg body weight) on postpartum day 10, whereas cataract formation occurred in only 33.3% of rat pups that had received selenite as well as an intraperitoneal injection of the extract of C. maritima (350 mg/kg body weight) for five consecutive days. These observations suggest that the ethanolic extract of C. maritima may prevent experimental selenite-induced cataractogenesis.

Sub-lethal impact of carbaryl on food utilization in the freshwater prawn Macrobrachium malcolmsonii

This study determines the toxic effect of carbaryl (Sevin50% W.P) on the food utilization parameters in intermoult juveniles of the prawn, Macrobrachium malcolmsonii. The prawns (4.5-5.0 cm in length and 1.0-1.25 g wet wt.) were exposed to three sub-lethal concentrations of carbaryl (5.15, 7.73 and 15.47 microgl-1) for duration of 40 days. The toxic medium was renewed daily. The prawns were fed ad libitum with known energy quantity of boiled goat liver on daily basis. The overall wet weight gain was calculated. The energy lost through unconsumed food (15-60%), faeces (15-109%), ammonia excretion (9-27%) and moults (13-26%) of the prawns were calculated. The feeding rate, the rate and efficiency of absorption, the metabolic and food conversion rates and the gross and net food conversions efficiencies were found to be significantly declined (p<0.05) in test prawns when compared to that of the control. The energy lost through faeces, ammonia excretion and exuvia was found to be significantly elevated (p<0.05) in test prawns than that of the control. The effectof carbaryl on the bioenergetics parameters was severe in the highest sub-lethal concentration, less in the intermediate concentration and least in the lowest sub-lethal concentration. The results indicated that decrease in feeding, absorption, metabolism and food conversion are interdependent and toxicity of carbaryl diverting energy from production to maintenance pathways, which ultimately resulting in declined growth of M. malcolmsonii.

Protective effect of chrysin on carbon tetrachloride (CCl4)—induced tissue injury in male Wistar rats

Chrysin, a natural flavonoid has been reported to possess potent anti-inflammatory, anti-cancer and antioxidation properties. In the present study, we aimed to evaluate the putative protective effect of chrysin, an isoflavone, on carbon tetrachloride (CCl4)-induced toxicity in male Wistar rats. Intraperitoneal administration of CCl4 (2 ml/kg) to rats for 4 days resulted in significantly elevated ( p < 0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH), when compared to normal rats. In addition, the tissues (liver, kidney and brain) and haemolysate samples showed considerable increase in levels ( p < 0.05) of malondialdehyde (MDA) and lowered levels ( p < 0.05) of reduced glutathione (GSH), vitamin C and E when compared to values in normal rats. Quantitative analysis of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) exhibited lower activities of these antioxidant enzymes in the tissues and haemolysate of CCl4-administered rats. The protective action of chrysin on CCl4-induced rat was demonstrated with SGPT, SGOT, ALP and LDH resuming to near normal levels, while the mean levels of GSH and of vitamin C and E were elevated, the mean activities of CAT, SOD and Gpx were enhanced and the mean level of MDA was lowered in the tissue and haemolysate samples when compared to the CCl4-exposed untreated rats. The expression of the iNOS gene appeared to be up-regulated in the liver and kidney samples of CCl4-exposed untreated rats, whereas in CCl4-exposed chrysin-treated rats, the mRNA transcript levels of iNOS approximated normal levels. These results strongly suggest that chrysin is able to prevent the oxidative damage induced by CCl4 in the liver, brain, kidney and haemolysate of male Wistar rats.

Alterations in the lenticular protein profile in experimental selenite-induced cataractogenesis and prevention by ellagic acid

BACKGROUND

Accumulating evidence suggests that oxidative stress underlies age-related formation of cataract, and that antioxidants retard cataractogenesis. This study aimed to evaluate whether ellagic acid, a natural polyphenol with antioxidant properties, prevents alterations in the lenticular protein profile in an experimental model of selenite cataract.

METHODS

Alterations in lenticular protein were determined by two-dimensional electrophoresis (2DE) and image analysis. Eluted αA-crystallin spots were analyzed by mass spectrometry. Western blot analysis was also performed to confirm the differential expression of certain crystallins and cytoskeletal proteins.

RESULTS

In cataractous lenses, 2DE and image analysis revealed approximately 45 and 60 prominent spots in soluble and insoluble protein fractions respectively. Analysis of the pI and molecular weight of protein spots revealed differences in the expression of crystallin proteins in soluble and insoluble fractions. Western blot analysis confirmed changes in the expression of αA- and βB1- crystallins in both soluble and insoluble protein fractions, while mass spectrometry confirmed the degradation of αA-crystallin in selenite cataractous lenses. Western blot analysis also confirmed the occurrence of altered expression of certain cytoskeletal proteins in insoluble fractions. However, the lenticular protein profile in lenses from selenite-challenged, ellagic acid-treated rats was essentially similar to that noted in lenses from normal rats.

CONCLUSIONS

The present study confirms the importance of structural and cytoskeletal proteins in the maintenance of lenticular transparency; the results also suggest that ellagic acid prevents lenticular protein alterations induced by selenite in an experimental setting.

Bacopa monniera leaf extract up-regulates tryptophan hydroxylase (TPH2) and serotonin transporter (SERT) expression: implications in memory formation

AIM OF THE STUDY

To examine the effect of Bacopa monniera leaf ethanolic extract (BMEE) on the serotonergic system of postnatal rats with reference to learning and memory.

MATERIALS AND METHODS

From postnatal day (PND)-15-29, rats were treated with BMEE (40 mg/kg BW+0.5% gum acacia) by oral gavage. Behavioural tests (Y-maze, hole-board and passive avoidance) were used to evaluate their learning (PND-32-37) and retention of memory (PND-47-53). Effect of BMEE on neurotransmitter system was analyzed by ELISA and semi-quantitative polymerase chain reaction (PCR).

RESULTS

Oral administration of BMEE improved learning and retention of memory significantly in all behavioural tasks. Following BMEE treatment, the level of serotonin (5-HT) increased while dopamine (DA) decreased significantly. We also found variation in the level of acetylcholine (ACh). However, no significant changes were observed in the level of ACh and glutamate (Glu). The level of 5-HT was significantly elevated up to PND-37 and was then restored to normal level on PND-53. Interestingly, concomitant up-regulation was recorded in the mRNA expression of serotonin synthesizing enzyme tryptophan hydroxylase-2 (TPH2) and serotonin transporter (SERT) on PND-29 and PND-37, which was restored on PND-53.

CONCLUSIONS

The results suggest that BMEE treatment significantly enhances the learning and retention of memory in postnatal rats possibly through regulating the expression of TPH2, 5-HT metabolism and transport.

Assessment of dominance hierarchy through urine scent marking and its chemical constituents in male blackbuck Antelope cervicapra, a critically endangered species

In ungulates the process of chemical communication by urinary scent marking has been directly related to reproductive dominance, territorial defense and proximity to resources. The differences in the frequency of urine marking and chemical composition of urine of males Antelope cervicapra before, during and after the dominance hierarchy period were assessed. The variations in the urine marking and its chemical profiles of dominant males (n=9), bachelors (n=5) and sub-adult males (n=5) were compared to find out how the dominance hierarchy influences the confined blackbuck herd under semi-natural captive conditions. The frequency of urine marking is significantly higher (p<0.001) in dominant males. Twenty-eight major constituents were identified in the urine of dominant males (before, during and after the dominance hierarchy period), bachelor and sub-adult males. Among these, three specific compounds namely, 3-hexanone (I), 6-methyl-5-hepten-2-one (II) and 4-methyl-3-heptanone (III) were seen only in dominant males urine during the dominance hierarchy period. Based on the behavioural observation and the unique chemical constituents in the urine, it is concluded that the dominant male scent odor suppresses aggression, scent marking, scent production and territorial patrolling activities of subordinate males, through which the dominant male establish their hierarchy and attains success in reproduction.

Keratitis due to Aspergillus flavus: clinical profile, molecular identification of fungal strains and detection of aflatoxin production

PURPOSE

To document the clinical profile of patients with keratitis due to Aspergillus flavus and to elaborate on differences in the aflatoxin-producing potential of keratitis strains versus environmental strains of A. flavus.

METHODS

Over a 6-month period, strains of Aspergillus flavus were isolated in culture from corneal scrape or biopsy material of patients who presented with suppurative keratitis (clinical isolates). The strains were confirmed to be A. flavus by molecular methods (amplification of the internal transcribed spacer 2 [ITS 2] region and direct sequencing followed by comparative GenBank analysis). The aflatoxin-producing potential of each strain was determined by thin-layer chromatography. The ability of each strain to form sclerotia in Czapek-Dox agar (CDA) after 7 days incubation at 30 degrees C in the dark and to produce a beige ring in yeast extract sucrose agar supplemented with methyl beta-cyclodextrin and sodium desoxycholate (YESD medium) after 3 days incubation at 30 degrees C was also assessed. For comparison, the tests were also run on 10 strains of A. flavus (identity confirmed by molecular methods) collected from local farming areas (environmental isolates).

RESULTS

Aflatoxin B1 was detected in 16 (80%) of 20 culture filtrate or mycelial homogenate samples of the clinical isolates (mean concentration: 366.7+/-125.4 parts per billion [ppb]) but in only eight (40%) of 20 samples of environmental isolates (mean concentration: 306.6+/-125.4 ppb). Seven of the eight aflatoxin-producing clinical isolates and two of the four aflatoxin-producing environmental isolates formed sclerotia (>400 microm) and a beige ring in culture.

CONCLUSIONS

Aflatoxin B1 was detected in a significantly higher percentage of growth samples of clinical isolates (80%) than growth samples of environmental isolates (40%) (chi(2)=6.667; p=0.0098); the therapeutic implications of this finding require further study. The production of sclerotia and a beige ring in culture appear to be useful markers of aflatoxin-producing potential in strains of A. flavus isolated from keratitis.

Alterations in lenticular proteins during ageing and selenite-induced cataractogenesis in Wistar rats

PURPOSE

To determine putative alterations in the major lenticular proteins in Wistar rats of different ages and to compare these alterations with those occurring in rats with selenite-induced cataract.

METHODS

Lenticular transparency was determined by morphological examination using slit-lamp biomicroscopy. Alterations in lenticular protein were determined by sodium dodecyl sulfate-PAGE (SDS-PAGE) and confirmed immunologically by western blot.

RESULTS

Morphological examination did not reveal observable opacities in the lenses of the rats of different age groups; however, dense nuclear opacities were noted in lenses of rats in the selenite-cataract group. Western blot assays revealed age-related changes in soluble and urea-soluble lenticular proteins. Decreased alphaA- and betaB1-crystallins in the soluble fraction and aggregation of alphaA-crystallin, in addition to the degraded fragment of betaB1-crystallin, in the urea-soluble fraction appeared to occur in relation to increasing age of the rats from which the lenses were taken; similarly, cytoskeletal proteins appeared to decline with increasing age. The lenses from rats in the selenite-cataract group exhibited similar changes, except that there was also high molecular weight aggregation of alphaA-crystallin.

CONCLUSIONS

The results of this study suggest that there is loss, as well as aggregation, of alphaA-crystallin in the aging rat lens, although there is no accompanying loss of lenticular transparency.

Regulatory effect of acetyl-l-carnitine on expression of lenticular antioxidant and apoptotic genes in selenite-induced cataract

Differential expression of apoptotic genes has been demonstrated in selenite-induced cataract. Acetyl-l-carnitine (ALCAR) has been shown to prevent selenite cataractogenesis by maintaining lenticular antioxidant enzyme and redox system components at near normal levels and also by inhibiting lenticular calpain activity. The aim of the present experiment was to investigate the possibility that ALCAR also prevents selenite-induced cataractogenesis by regulating the expression of antioxidant (catalase) and apoptotic [caspase-3, early growth response protein-1 (EGR-1) and cytochrome c oxidase subunit I (COX-I)] genes. The experiment was conducted on 9-day-old Wistar rat pups, which were divided into normal, cataract-untreated and cataract-treated groups. Putative changes in gene expression in whole lenses removed from the rats were determined by measuring mRNA transcript levels of the four genes by RT-PCR analysis, using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an internal control. The expression of lenticular caspase-3 and EGR-1 genes appeared to be upregulated, as inferred by detecting increased mRNA transcript levels, while that of COX-I and catalase genes appeared to be downregulated (lowered mRNA transcript levels) in the lenses of cataract-untreated rats. However, in rats treated with ALCAR, the lenticular mRNA transcript levels were maintained at near normal (control) levels. These results suggest that ALCAR may prevent selenite-induced cataractogenesis by preventing abnormal expression of lenticular genes governing apoptosis.

Prevention of selenite-induced cataractogenesis by rutin in Wistar rats

PURPOSE

To investigate whether rutin retards selenite-induced cataractogenesis in Wistar rat pups.

METHODS

On postpartum day ten, Group I rat pups received an intraperitoneal injection of saline. Group II and III rat pups received a subcutaneous injection of sodium selenite. Group III also received an intraperitoneal injection of rutin once daily on postpartum days 9-14. Both eyes of each pup were examined from day 16 up to postpartum day 30. After sacrifice, extricated pup lenses were analyzed for mean activities of catalase, superoxide dismutase, glutathione peroxidase, glutathione S-transferase, and glutathione reductase. In addition, the mean concentrations of reduced glutathione (GSH) and of malondialdehyde were analyzed in samples of lenses and hemolysate.

RESULTS

There was dense lenticular opacification in all of Group II, minimal opacification in 33.3% of Group III, no opacification in 66.7% of Group III, and no opacification in Group I. Significantly lower mean activities of lenticular antioxidant enzymes were noted in Group II, compared to Group I and III. Significantly lower mean concentrations of GSH and higher mean concentrations of malondialdehyde were noted in samples of hemolysate and lens from Group II, compared to the values in Group I and III.

CONCLUSION

Rutin prevents experimental selenite-induced cataractogenesis in rat pups, possibly by preventing depletion of antioxidant enzymes and of GSH, and by inhibiting lipid peroxidation.

Ultrastructural observations in gills and hepatopancreas of prawn Macrobrachium malcolmsonii exposed to mercury

The juveniles of M. malcolmsonii were exposed to 24.1 microg l(-1) of Hg fora period of 21 days. The gills and hepatopancreas of test prawns were sampled and processed for electron microscopic observations. Mitochondria are the organelle most affected in the gills of test prawns. The number of mitochondria and the electron-density of the matrix were found to be less in test prawns. The in-folding of cell membrane associated with mitochondria was absent in test prawns. This suggests that operation of the mitochondrial pumps was affected in the gills of test prawns. Vacuoles with crystalline granular inclusions were noted in the gills of test prawns. These are suggestive of metal-rich inorganic deposits or granules representing detoxified dumps of Hg. In the hepatopancreas of test prawns, the tubules exhibit vacuoles with granular inclusion and the cell cytoplasm contains electron-dense granules, which indicate a storage detoxification of Hg. The mitochondria were shrunken in the hepatopancreas of test prawns. This suggests attenuation of its function. The rough endoplasmic reticulum appeared vesiculated and dilated. These reactions denote the hyperactivity of the rough endoplasmic reticulum. Membranous whorl-like structures with myelin fibers and residual bodies were seen in the hepatopancreas of test prawns. Such structures indicate the involvement of lysosomal breakdown in detoxification process. The ultrastructural alterations are suggestive of the operation of compensatory mechanisms within the test prawns to enable it to tolerate Hg toxicity. However these alterations would have an impact on the cellular integrity of the gills and hepatopancreas and such alterations can be taken as 'biomarkers' for assessing Hg pollution in the aquatic environment.

Evaluation of lenticular antioxidant and redox system components in the lenses of acetyl-L-carnitine treatment in BSO-induced glutathione deprivation

PURPOSE

To investigate whether acetyl-L-carnitine (ALCAR) retards L-buthionine-(S,R)-sulfoximine (BSO)-induced cataractogenesis in Wistar rat pups.

METHODS

On postpartum day 3, group I pups received intraperitoneal (ip) saline and group II and group III pups received i.p. injections of BSO once daily for three consecutive days. In addition, group III pups received ip ALCAR once daily from postpartum days 3-15. Both eyes of each pup were examined up from postpartum day 16 to day 30. After sacrifice, extricated pup lenses were analyzed for antioxidant and redox system components.

RESULTS

There was dense lenticular opacification in all group II pups, minimal opacification in 40% of group III pups, and no opacification in 60% of group III pups and in all of group I pups. Group II lenses exhibited significantly lower values of antioxidant and redox system components and higher malondialdehyde concentrations than in group I or group III lenses.

CONCLUSIONS

ALCAR prevents cataractogenesis in the BSO-induced cataract model, possibly by inhibiting depleting antioxidant enzyme and redox system components and inhibiting lipid peroxidation.

Anticataractogenic effect of an extract of the oyster mushroom, Pleurotus ostreatus, in an experimental animal model

PURPOSE

To evaluate the efficacy of Pleurotus ostreatus extract in preventing selenite-induced cataractogenesis.

METHODS

In vitro, enucleated rat lenses, divided into one control and three experimental groups (selenite only, simultaneous selenite and extract, initial extract and subsequent selenite), underwent morphological and biochemical evaluation. The anti-cataractogenic effect was also evaluated in vivo.

RESULTS

In vitro, simultaneous incubation of extract with selenite-challenged lenses caused a decrease in lens opacification by maintaining antioxidant components at near normal levels. In vivo, P.ostreatus (300 mg/kg body weight) prevented cataract in 75% of rats.

CONCLUSION

Extract of P. ostreatus prevents experimental selenite-induced cataractogenesis.

Manifestation of carbaryl toxicity on soluble protein and histopathology in the hepatopancreas and gills of the prawn, Macrobrachium malcolmsonii

The present study examined alterations in the protein pattern and histopathology of the hepatopancreas and gills of Macrobrachium malcolmsonii following exposure to Sevin, the commercial grade of carbaryl (1-Naphthylmethyl carbamate) pesticide. Juvenile prawns were exposed to sub-lethal concentrations 5.15 microg l(-1), 7.73 microg l(-1) and 15.47 microg l(-1) of carbaryl for 21 days. Samples were obtained from the hepatopancreas and gills of prawns. The concentration of buffer soluble protein in tissues of test prawns was significantly (p<2.5%) lower than the control. This suggests that proteins were utilized to generate energy in order to withstand carbaryl induced toxic stress. Polypeptide bands of different molecular mass (150-10 kDa) in tissues of test prawns stained less intensely than those in control. This indicates that carbaryl toxicity caused protein degradation in tissues of test prawns. The histology of the hepatopancreas and gills showed few marked pathological changes in prawns exposed to carbaryl. These include rupture of the basal laminae, abnormal infiltration/aggregation of hemocytes in the interstitial sinus of the hepatopancreas and in the hemocoelic space of gill lamellae, fused gill lamellae and necrosis like appearance both in the tubules of the hepatopancreas and gill lamellae. The structural alterations observed in the hepatopancreas and gills of the prawns suggest that carbaryl caused tissue damage in M. malcolmsonii. Protein degradation is a phenomenon in damaging tissues, and thus, under such condition the hepatopancreas and gills of test prawns would not perform their vital functions, which in turn ultimately affect the survival and growth of M. malcolmsonii. The changes noted in protein and histology of test prawns can be taken as biomarkers for monitoring pesticide pollution in aquatic environments. Since this species of prawn is a nutritious delicacy to human being, monitoring aquatic pollution by carbaryl is warranted.

Use of chlorazol black E mounts of corneal scrapes for diagnosis of filamentous fungal keratitis

PURPOSE

To determine whether chlorazol black E, a chitin-specific stain, can be used to detect fungal filaments in corneal scrapings and to compare its sensitivity as a diagnostic aid for fungal keratitis with that of gram and lactophenol cotton blue stains.

DESIGN

Prospective study, laboratory investigation.

METHODS

Between December 1, 2005 and July 31, 2006, corneal scrapes from 163 patients with ulcerative keratitis were used for culture and to prepare smears that were stained by lactophenol cotton blue, chlorazol black E, or gram stains. A diagnosis of fungal keratitis was established if fungal growth occurred on the inoculated areas of multiple culture plates.

RESULTS

Fungi were isolated from corneal scrapes of 82 patients. Taking fungal culture positivity as the gold standard for diagnosis of fungal keratitis, direct microscopic examination of chlorazol black E mounts had a sensitivity of 82% and specificity of 98%; culture results and chlorazol black E results were identical in 89.6% of patients. Lactophenol cotton blue mounts and gram-stained smears had a sensitivity of 85%, specificity of 90% to 91%, and 88% agreement with culture results.

CONCLUSIONS

Chlorazol black E can be used for detection of fungal filaments in corneal scrapings; however, it is less sensitive than lactophenol cotton blue and gram stains as a diagnostic aid for fungal keratitis.