Nitroglycerin, a nitric oxide generator attenuates ferric nitrilotriacetate-induced renal oxidative stress, hyperproliferative response and necrosis in ddY mice

Nitric oxide (NO) is a short lived, readily diffusible intracellular messenger molecule associated with multiple organ-specific regulatory functions. In this communication, we elucidate the effect of exogenous NO administration, using nitroglycerin (GTN), on ferric nitrilotriacetate (Fe-NTA)-induced renal oxidative stress, hyperproliferative response and necrosis in ddY mice. Fe-NTA is a known complete renal carcinogen as well as renal and hepatic tumor promoter, which act by generating oxidative stress in the tissues. GTN treatment to ddY mice prior to Fe-NTA administration resulted in a highly significant protection against Fe-NTA-induced renal oxidative stress, hyperproliferative response and necrosis. In oxidative stress protection studies, the decrease in the level of renal glutathione and antioxidant enzyme activities induced by Fe-NTA were significantly reversed by GTN pretreatment in a dose-dependent manner (12-46% recovery, P<0.05-0.001). GTN pretreatment also resulted in a dose-dependent inhibition (24-39% inhibition, P<0.05-0.001) of Fe-NTA-induced lipid peroxidation as measured by TBARS formation in renal tissues. Similarly, in hyperproliferation protection studies, GTN pretreatment showed a strong inhibition of Fe-NTA-induced renal ornithine decarboxylase (ODC) activity (51-57% inhibition, P<0.001) and [3H]thymidine incorporation (43-58% inhibition, P<0.001) into renal DNA. GTN pretreatment almost completely prevented kidney biomolecules from oxidative damage and protected the tissue against the observed histopathological alterations. From this data, it can be concluded that exogenously produced NO from GTN might scavenge reactive oxygen species (ROS) and decreases toxic metabolites of Fe-NTA and thereby inhibiting renal oxidative stress. In addition, exogenously produced NO can also inhibit Fe-NTA-induced hyperproliferative response by down-regulating the activity of ODC and the rate of [3H]thymidine incorporation into renal DNA and could be suggested as another possible clinical application for this NO-donor (GTN, traditionally used as a vasodilator) in oncological medicine.     

Aerobic salivary bacteria in wild and captive Komodo dragons

During the months of November 1996, August 1997, and March 1998, saliva and plasma samples were collected for isolation of aerobic bacteria from 26 wild and 13 captive Komodo dragons (Varanus komodoensis). Twenty-eight Gram-negative and 29 Gram-positive species of bacteria were isolated from the saliva of the 39 Komodo dragons. A greater number of wild than captive dragons were positive for both Gram-negative and Gram-positive bacteria. The average number of bacterial species within the saliva of wild dragons was 46% greater than for captive dragons. While Escherichia coli was the most common bacterium isolated from the saliva of wild dragons, this species was not present in captive dragons. The most common bacteria isolated from the saliva of captive dragons were Staphylococcus capitis and Staphylococcus capitis and Staphylococcus caseolyticus, neither of which were found in wild dragons. High mortality was seen among mice injected with saliva from wild dragons and the only bacterium isolated from the blood of dying mice was Pasteurella multocida. A competitive inhibition enzyme-linked immunosorbent assay revealed the presence of anti-Pasteurella antibody in the plasma of Komodo dragons. Four species of bacteria isolated from dragon saliva showed resistance to one or more of 16 antimicrobics tested. The wide variety of bacteria demonstrated in the saliva of the Komodo dragon in this study, at least one species of which was highly lethal in mice and 54 species of which are known pathogens, support the observation that wounds inflicted by this animal are often associated with sepsis and subsequent bacteremia in prey animals.     

Influence of cultivation conditions on citrate production by Aspergillus niger in a semi-pilot-scale plant

The influence of some fermentation parameters on the semi-pilot scale (alteration of growth conditions,e.g., sugar concentration, incubation temperature and initial pH) on citrate production was demonstrated in parent and mutant strains ofAspergillus niger. Raw material from sugar industry (cane molasses) was examined as basal fermentation medium in a stirred stainless-steel 15-L fermentor. After growth on medium with 150 g/L sugar, the parent strain produced 51.2 g/L citric acid; the mutant strain achieved production maximum of 96.2 g/L. Comparing the growth, kinetic (volumetric substrate uptake rate, rate of substrate consumption and volumetric productivity rate) and production parameters it was found that the mutant strain grows more rapidly, with slightly changed morphology (intermediate, shiny round pellets with diameter 0.6–0.7 mm), and exhibits a higher citrate production and higher efficiency of sugar utilization.     

Dogs as alternative intermediate hosts of Taenia solium in Papua (Irian Jaya), Indonesia confirmed by highly specific ELISA and immunoblot using native and recombinant antigens and mitochondrial DNA analysis

Serology (ELISA and immunoblot) using native glycoproteins, affinity purified glycoproteins, and a recombinant antigen is known to be highly specific to Taenia solium cysticercosis in humans and pigs. These techniques were applied for dogs in the highly endemic area of cysticercosis in Papua (Irian Jaya), Indonesia. Analysis of dog sera by both ELISA and immunoblot revealed 7 of 64 dogs were highly positive. Examination of two sero-positive dogs revealed cysticerci of T. solium in the brain and heart of these dogs. Mitochondrial DNA analysis confirmed that they were the same as T. solium previously confirmed from pigs and biopsies from local people from Irian Jaya. It is suggested that the life cycle of T. solium may be completed not only between humans and pigs but also between humans and dogs.     

Transition metal acetylsalicylates and their anti-inflammatory activity

Mononuclear and binuclear transition metal [Co(II), Cu(II), Ni(II) and Zn(II)] acetylsalicylates of the type [M(L)2], [M(L)2Cl2] and [(M)2(L)4] have been prepared and characterized on the basis of their physical, spectral and analytical data. The complexes have been investigated in an in vivo animal model for anti-inflammatory activity and show a better effect and a more potent action than acetylsalicylic acid.     

Oesophageal cancer in Africa

Oesophageal cancer, the eighth most frequent cancer in the world occurs as two main subtypes, squamous cell carcinoma (more prevalent in developing countries) and adenocarcinoma (more common in developed countries). Certain populations of central, eastern, and southern Africa display very high frequencies of oesophageal squamous cell carcinoma, presenting a serious health burden to the continent. Most patients are diagnosed at a late stage because of the asymptomatic development of the disease, with associated poor prognosis. A better understanding of the aetiological agents and molecular mechanisms involved in the development of oesophageal squamous cell carcinoma may offer opportunities to reduce exposure to environmental risk factors and also allow early diagnosis or predict response to therapy. Epidemiologic studies have identified smoking, alcohol consumption, diets poor in fresh fruit and vegetables, consumption of foods contaminated with Fusarium verticillioides, and HPV infection as risk factors associated with the development of this disease in Africa. Although we have an incomplete understanding of the molecular events involved in the development of oesophageal squamous cell carcinoma, advances have been made that suggest lines of future exploration. South African patients with oesophageal squamous cell carcinoma display a lower incidence of point mutations in the p53 gene than described elsewhere, suggesting that the profile of aetiological agents may be different than described for other high-risk areas for oesophageal cancer. Recent studies suggest that RARbeta and COX II is frequently downregulated and upregulated, respectively, in oesophageal squamous cell carcinomas. These results suggest potential therapeutic opportunities that can be exploited to combat the high incidence of this disease in Africa.     

Heart and breast muscle mitochondrial dysfunction in pulmonary hypertension syndrome in broilers (Gallus domesticus)

This study was conducted to determine function and defects in electron transport in muscle mitochondria of meat chickens (broilers) with pulmonary hypertension syndrome (PHS). The respiratory control ratio (RCR, indicative of respiratory chain coupling) was higher in the control than in PHS breast and heart muscle mitochondria, but there were no differences in the ADP/O (an index of oxidative phosphorylation). Sequential additions of ADP improved the RCR in the control breast muscle mitochondria and the ADP/O in PHS breast and heart muscle mitochondria. Basal hydrogen peroxide production, (an indicator of electron leak), was higher in PHS breast and heart muscle mitochondria than in controls and differences in electron leak in PHS mitochondria were magnified by inhibiting electron transport at Complex I and III (cyt b(562)). Complex I activity was lower in PHS heart mitochondria but there was no difference in Complex II activity. Thus, compared to controls, PHS mitochondria exhibited site-specific defects in electron transport within Complex I and III that could contribute to lower respiratory chain coupling. Additionally, it appears that healthy broilers may exhibit higher basal levels of electron leak compared to other avian species. Together, these findings provide insight into inefficient cellular use of oxygen that may contribute to the development of PHS in broilers.     

Bovine blastocyst development from oocytes injected with freeze-dried spermatozoa

Pronuclear formation, and the chromosomal constitution and developmental capacity of bovine zygotes formed by intracytoplasmic sperm injection with freeze-dried (lyophilized) spermatozoa were evaluated. Frozen-thawed spermatozoa were selected, freeze-dried, and stored at 4 degrees C until use. After 22-24 h of in vitro maturation oocytes were denuded and injected singly with a lyophilized spermatozoon. Injected oocytes were activated by treatment with 10 microM ionomycin (5 min) alone and in combination with 1.9 mM 6-dimethylaminopurine (DMAP) for 4 h. Ionomycin plus DMAP activation treatment resulted in a significantly higher proportion of sperm-injected oocytes with two pronuclei than was found after activation with ionomycin alone (74% vs. 56%; P < 0.03). The rates of cleavage, morula, and blastocyst development of sperm-injected oocytes treated with ionomycin plus DMAP were higher than after activation with ionomycin alone (63.3%, 34.2%, and 29.6% vs. 44.7%, 18.7%, and 10.6%, respectively; P < 0.05). Seventy-three percent of blastocysts produced with lyophilized sperm were diploid. These results demonstrate that in vitro-matured bovine oocytes can be fertilized with freeze-dried sperm cells, and that resultant zygotes can develop into karyotypically normal blastocysts.     

<Emphasis Type="Italic">Trichiurus nickolensis</Emphasis>, a new hairtail from Australia belonging to the <Emphasis Type="Italic">Trichiurus russelli</Emphasis> complex (Perciformes: Trichiuridae)

A new hairtail, Trichiurus nickolensis, is described on the basis of ten specimens collected off northwestern Australia, off the Northern Territory, and in the Gulf of Carpentaria, Queensland. The new species strongly resembles T. brevis Wang and You in Wang et al., 1992, off Hainan Island, South China Sea, and T. russelli Dutt and Thankam, 1966, off the Waltair Coast, Andhra Pradesh, India, in having the highest point of the supraoccipital crest situated directly above the posterior margin of the eye and a relatively short caudal peduncle. Trichiurus nickolensis differs from those two species in being strongly pigmented on the anterior section of the dorsal fin membrane (vs. slightly pigmented), and having a dorsal head margin that appears concave in lateral view, rises gently from snout tip to above middle of orbit, and then extends more steeply to dorsal fin origin (vs. rising gently from tip of snout to dorsal fin origin). The new species also has a greater number of dorsal fin rays (III, 138–143 vs. III, 127–132 and III, 127–131 in T. brevis and T. russelli, respectively) and total vertebrae (160–166 vs. 147–155 and 149–153), and shorter preanal length (mean 30% TL vs. 33% TL and 35% TL), head length (11% TL vs. 12% TL and 13% TL) and upper jaw length (4% TL vs. 5% TL and 5% TL).     

New class of steroidal alkaloids from Fritillaria imperialis

Two members of a new class of C-nor-D-homo steroidal alkaloids, impranine (1). and dihydroimpranine (2). along with a new pyridyl-pregnane-type steroidal alkaloid, fetisinine (3). and a known base, korsevine (4). were isolated from the bulbs of Fritillaria imperialis. The structures of the compounds were established on the basis of spectroscopic techniques and some chemical transformations. Compounds 1 and 2 form a new class of steroidal alkaloids, named as "impranane."