Less-Frequent Fusarium Species of Clinical Interest: Correlation between Morphological and Molecular Identification and Antifungal Susceptibility

Forty-eight Fusarium isolates morphologically identified as belonging to seven species of clinical interest (i.e., Fusarium chlamydosporum, Fusarium dimerum, Fusarium incarnatum, Fusarium napiforme, Fusarium nygamai, Fusarium proliferatum, and Fusarium sacchari) were characterized molecularly by the analysis of the sequences of the TUB region of the β-tubulin gene. F. chlamydosporum and F. dimerum were the most genetically heterogeneous species. A high degree of correlation between the morphological and molecular identification was shown among the isolates studied. A table with the key morphological features for the identification of these Fusarium species is provided. The antifungal susceptibilities of the Fusarium isolates to 11 antifungal drugs were tested; terbinafine was the most active drug against all the species tested with the exception of F. incarnatum, for which amphotericin B was the most active.The most frequent species causing fusariosis are Fusarium solani, Fusarium oxysporum, and Fusarium verticillioides (1, 16, 47), but several other species are also found to cause human infections, although less frequently. Some of these species are Fusarium chlamydosporum, Fusarium dimerum, Fusarium incarnatum, and the following other species that are included into the Gibberella fujikuroi species complex: Fusarium napiforme, Fusarium nygamai, Fusarium proliferatum, and Fusarium sacchari (30, 31). These species have been associated with different types of infection, in particular with keratomycoses and other ocular infections (10) and with disseminated infections in immunocompromised patients (2, 6, 17, 20, 23, 24, 26, 39, 41, 43, 44). The real incidence of these species is unknown since they are poorly known and laboratorians and clinical microbiologists are not generally aware of their possible presence in human infections.Since the species of Fusarium are generally resistant to all the available antifungal drugs (40), it could be considered that speciation of Fusarium is necessary only for epidemiological purposes. However, some in vitro data concerning particular species seem to be very promising and deserve to be investigated clinically. For instance, F. verticillioides isolates were susceptible to posaconazole and terbinafine and Fusarium thapsinum isolates to terbinafine (4). The identification of fusaria to the species level is not easy, and in numerous clinical cases the etiological agent is reported as being a Fusarium sp. However, several recent studies have demonstrated the usefulness of molecular methods for the identification of those Fusarium species that are difficult to distinguish morphologically (1, 4, 47). In recent years, the in vitro antifungal susceptibilities of the most frequent species of Fusarium have been evaluated (1, 3, 4, 40, 47), but only a few isolates of the less-common species have been studied. The objectives of our study were (i) to evaluate the correlation between the morphological and the molecular identification of less-frequent Fusarium species isolates received by our laboratory and (ii) to determine the antifungal susceptibilities of isolates representative of those less-common Fusarium species of clinical interest identified molecularly.     

Effects of chronic noise stress on spatial memory of rats in relation to neuronal dendritic alteration and free radical-imbalance in hippocampus and medial prefrontal cortex

Spatial memory is coordinated with different brain regions especially hippocampus (HIP) and medial prefrontal cortex (mPFC). Influence of noise stress on working and reference memory error in rats was evaluated by radial eight-arm maze experiment. Changes in the dendritic count were observed in the brain regions such as CA1, CA3 regions of HIP and layers II, III of mPFC. In order to understand the possible mechanism behind noise stress-induced changes, free radical status and acetylcholinesterase (AChE) activity in HIP and mPFC were evaluated. Plasma corticosterone level was also evaluated. Results obtained in this study showed that after noise-stress exposure, 100 dBA/4h per day for 30 days, working and reference memory error increased significantly (P < 0.05) when compared to control animals. Neuronal dendritic count in the HIP was reduced in the 2nd and 3rd order dendrites but not in the mPFC. Superoxide dismutase, lipid peroxidation, plasma corticosterone level and AChE activity were significantly increased in the 1 day, 15 days and 30 days stress groups animal significantly. Catalase and glutathione peroxidase activity were increased in the 1 day and 15 days noise-stress groups but decreased in the 30 days noise-stress group and GSH level was decreased in all the stress exposed animals. In conclusion, oxidative stress, increased AChE activity, reduced dendritic count in HIP, mPFC regions and elevated plasma corticosterone level which develops in long-term noise-stress exposed rats, might have caused the impairment of spatial memory.     

Detoxification of formate by formate dehydrogenase-loaded erythrocytes and carbicarb in folate-deficient methanol-intoxicated rats

BACKGROUND: Formic acid is a toxic metabolite responsible for the metabolic acidosis in methanol poisoning. Formate dehydrogenase (EC 1.2.1.2) converts formate into CO2 in the presence of NAD. We examined the in vitro and in vivo efficiency of formate dehydrogenase-loaded carrier erythrocytes along with carbicarb in eliminating the formate in methanol-intoxicated folate-deficient rats. METHOD: Formate dehydrogenase-loaded erythrocytes were prepared by hypotonic dialysis method. Carbicarb (carb) (equimolar solution of sodium carbonate and sodium bicarbonate) was used to treat metabolic acidosis. Folate depletion was induced by methotrexate (MTX) treatment. Experimental design consisted of 8 groups: saline control, methanol control, MTX control, ELE control, MTX-methanol control, MTX-methanol-carb, MTX-methanol-carb-ELE, and MTX-MeOH-ELE group. Male Wistar rats treated with MTX (0.3 mg/kg) for a week were injected (i.p.) with methanol (4 g/kg). Twelve hours later, the carbicarb solution was infused, and then a formate dehydrogenase-loaded erythrocytes suspension (40% hematocrit) was infused (i.v.) in bolus. Blood samples were collected every hour for 4 h from the cannulated left jugular vein. Blood methanol and formate were estimated respectively with HPLC and fluorimetric assay. Blood pH, blood pO2, pCO2 and bicarbonate were also measured. RESULTS: There was marked elimination of formate in selected groups. CONCLUSION: Formate dehydrogenase-loaded erythrocytes, along with carbicarb, facilitates removal of formate, in methanol poisoning.     

Methanol-induced oxidative stress in rat lymphoid organs

Methanol is primarily metabolized by oxidation to formaldehyde and then to formate. These processes are accompanied by formation of superoxide anion and hydrogen peroxide. This paper reports data on the effect of methanol on antioxidant status and lipid peroxidation in lymphoid organs such as the spleen, thymus, lymph nodes and bone marrow of rats. Male Wistar albino rats were intoxicated with methanol (2.37 g/kg b.w intraperitoneally) for detecting toxicity levels for one day, 15 d and 30 d, respectively. Administration of methanol at 15 and 30 d significantly (p<0.05) increased lipid peroxidation and decreased the enzymatic (superoxide dismutase, catalase, glutathione peroxidase) and non-enzymatic antioxidants (reduced glutathione and vitamin C) in lymphoid organs. However, lipid peroxidation and enzymatic and non-enzymatic antioxidants in the acute methanol exposed group animals were found to be significantly (p<0.05) increased. In one day methanol intoxication, the levels of free radicals initially increased, and to remove these free radicals, antioxidants levels were elevated, which generally prevented oxidative cell damage. But in longer periods of intoxication, when the generation of reactive free radicals overwhelmed the antioxidant defense, lipid peroxidation increased. Further, decreased antioxidants in 15 and 30 d methanol intoxication may have been due to overutilization of non-enzymatic and enzymatic antioxidants to scavenge the products of lipid peroxidation. In addition, the liver and kidney markers of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine significantly increased. This study concludes that exposure to methanol causes oxidative stress by altering the oxidant/antioxidant balance in lymphoid organs of the rat.     

Which is the real gold standard for small-volume renal tumors? Radical nephrectomy versus nephron-sparing surgery

BACKGROUND AND PURPOSE: Until recently, the gold standard for treatment of localized renal-cell carcinoma with a normal contralateral unit was deemed to be a formal radical nephrectomy. Advocates of nephron-sparing surgery have recently challenged this concept; we wished to evaluate the evidence to determine which treatment is objectively superior for patients with renal tumors up to 4 cm. MATERIALS AND METHODS: MEDLINE, CANCERLIT, and EMBASE computer literature searches were performed to identify peer-reviewed papers pertaining to radical nephrectomy (RN), nephron-sparing surgery (NSS), or comparisons of these methods for tumors as large as 4 cm in maximum diameter. Review of the bibliographies of recovered articles and data in recent textbooks were used to supplement the computerized searches. There were a total of 797 cases in the RN group and 1211 in the NSS group. The parameters specifically evaluated were evidence of local recurrence, disease progression, and death within 33 months, this period being chosen primarily because it was the shortest follow-up in the studies evaluated. The data were then subjected to rigorous statistical analysis. Laparoscopic radical nephrectomy (LRN) and laparoscopic nephron-sparing surgery (LNSS) articles were also reviewed; however, current follow-up periods were considered too short to draw a statistically significant conclusion. RESULTS: Disease-specific survival rates (P=0.001; Mann-Whitney test) as well as the incidence of metastases (P<0.05; Mann-Whitney test) were significantly better in the NSS group. The incidence of local recurrence (P=0.22; Mann-Whitney test) was not significantly different. It should be borne in mind that there are different follow-up periods for each study, and this may have had an impact on the results. CONCLUSION: Nephron-sparing surgery seems to be as effective as RN in patients with renal cell tumours up to 4 cm, although only a large randomized controlled trial with long follow-up periods would provide a definite answer.     

Anti-ulcer activity of ethanol extract of Terminaliapallida Brandis. in Swiss albino rats

Ethanol extract of Terminalia pallida Brandis. (EETP) was evaluated for its anti-ulcer activity against various models of ulcers, such as drug-induced ulcers, histamine-induced ulcers and ethanol-induced ulcers in Swiss albino rats. The EETP at the doses of 250 and 500 mg/kg per os (p.o.) exhibited significant protection against ulcers produced by indomethacin, histamine and the effect was comparable to that of the reference drug famotidine (30 mg/kg b.w) orally. The extract also afforded significant protection against ethanol-induced gastric ulceration. Meanwhile, EETP significantly lowered the elevated lipid peroxide level (thiobarbituric acid reactive substances (TBARS)) and restored the altered glutathione level in ethanol-induced gastric ulceration. The present investigation revealed that the EETP exhibited significant anti-ulcer activity by enhancing antioxidant potential of the gastric mucosa, thereby reducing mucosal damage.     

Lack of poly(ADP-ribose) polymerase-1 gene product enhances cellular sensitivity to arsenite

Arsenite (As3+) has long been known to induce cancer and other degenerative diseases. Arsenite exerts its toxicity in part by generating reactive oxygen species. Identification of genetic factors that contribute to arsenic mutagenicity and carcinogenicity is critical for the treatment and prevention of arsenic exposure in human population. As poly(ADP-ribose) polymerase (PARP) is critical for genomic DNA stability, role of PARP-1 was evaluated in arsenic-induced cytotoxic and genotoxic effects. Our study revealed that telomere attrition, probably owing to arsenite-induced oxidative stress, was much more pronounced in PARP-1-/- mouse embryonic fibroblasts (MEF; 40%) compared with PARP-1+/+ MEFs (10-20%). Correlation observed between telomere reduction and apoptotic death in PARP-1 null cells strongly indicates that the telomere attrition might be a trigger for enhanced apoptotic death after arsenite treatment. Elevated DNA damage detected by alkaline comet assay points to an impaired repair ability of arsenite-induced DNA lesions in PARP-1-/- MEFs. Consistent with elevated DNA damage, increased micronuclei induction reflecting gross genomic instability was also observed in arsenite-treated PARP-1-/- MEFs. Microarray analysis has revealed that arsenite treatment altered the expression of about 311 genes majority of which have known functions in cellular responses to stress/external stimulus and cell growth and/or maintenance. Our results suggest an important role for PARP-1 gene product in the maintenance of chromosome-genome stability in response to arsenite-induced DNA damage.     

Evaluation of antipyretic potential of Vernonia cinerea extract in rats

The methanol extract of the whole plant of Vernonia cinerea (MEVC) was evaluated for its antipyretic potential on normal body temperature and yeast-induced pyrexia in rats. MEVC significantly reduced the normal body temperature at doses of 250 and 500 mg/kg body weight p.o. MEVC also lowered the elevated body temperature in the case of yeast-induced pyrexia in a dose dependent manner. The antipyretic effect of the extract at a dose of 500 mg/kg was identical to that of the standard drug paracetamol.