Xylitol formation by Candida guilliermondii in media containing different nitrogen sources

The xylose conversion into xylitol by Candida guilliermondii was evaluated in semi-synthetic media supplemented with different nitrogen sources in a ratio C/N equal 25.6. It was noticed that the xylitol yield was around 80% and also that the type of nitrogen source did not influence this bioconversion.     

Xanthine oxidase inhibitory activity of Lychnophora species from Brazil ("Arnica")

Twenty-two extracts from five Lychnophora species and one Lychnophoriopsis species, traditionally used in Brazil as analgesic, anti-inflammatory, and to treat bruise and rheumatism were examined for the inhibition of xanthine oxidase (XO), the enzyme that catalyses the metabolism of hypoxanthine and xanthine into uric acid. Sixteen extracts were tested. All of them were found to have excellent XO inhibitory activity, with inhibitions greater than 38% at 100 microg/mL in the assay mixture. The most active plants examined were Lychnophora trichocarpha, Lychnophora ericoides, Lychnophora staavioides and Lychnophoriopsis candelabrum, with inhibitions of 77%, 78%, 66% and 63% at 100 microg/mL, respectively, and IC(50) values of 6.16, 8.28, 33.97 and 37.70 microg/mL, respectively.     

Embryotoxic effects of 2,3,7,8 tetrachlorodibenzo-p-dioxin administered to female rats before mating

2,3,7,8-Tetrachlorodibenzo-p-dioxin was administered to female rats by gavage for 2 consecutive weeks at daily doses of 0, 0.125, 0.5, and 2 μg/kg. After treatment females were caged with untreated males. All dams were killed on Day 21 of gestation. Their reproductive statuses were recorded and live fetuses were examined for external, visceral, and skeletal malformations. At 0.125 μg/kg no effects were observed on both maternal and fetal toxicity; 0.5 μg/kg reduced maternal weight gain and increased postimplantation loss. At 2 μg/kg the following features became evident: reduction of both maternal weight gain and ovulation rate, increase of pre- and postimplantation loss, and fetal growth retardation. Also, malformed fetuses were observed at this dose level.     

Reduction and binding of arsenate in marmoset monkeys

The metabolism of ⁷⁴As-arsenate (As V, 0.4 mg As/kg body weight, IV) in marmoset monkeys (two males and two females) was studied. Unlike all other animal species studied so far, the marmoset was found to be unable to metabolize the arsenate to dimethylarsinic acid. Most of the absorbed arsenate was reduced to arsenite (As III) in vivo. Only 20% was excreted in the urine as unchanged As V. A further 20% of the dose was excreted as As III. The rest of the As III produced was bound to the tissues, giving a distribution picture very similar to that reported earlier for marmoset monkeys given arsenite. The tissues with longest retention of arsenic were the liver, upper gastrointestinal tract (oral cavity and esophagus), skin, kidneys and gall bladder. The pronounced accumulation in the liver resulted from specific binding of arsenic to the rough microsomal membranes, unique to this animal species.At the time of this study, visiting researcher at the National Institute of Environmental Medicine and the Department of Environmental Hygiene, the Karolinska Institute, Stockholm, Sweden     

Tissue distribution and retention of74As-dimethylarsinic acid in mice and rats

The metabolism of dimethylarsinic acid (DMA), a common pesticide and the primary metabolite of inorganic arsenic in mammals, has been studied in mice and rats. About 80% of an oral dose (0.4 mg As/kg body weight) was absorbed from the gastrointestinal tract. In the mice, more than 99% of the dose was eliminated within 3 days, as compared to about 50% in the rats, mainly due to accumulation in the blood. The tissue distribution in the mice was characterized by highest initial (0.5–6 hr) concentrations in kidneys, lungs, intestinal mucosa, stomach, and testes. Tissues with longest retention time were lungs, thyroid, intestinal walls and lens. No demethylation of the⁷⁴As-DMA to inorganic arsenic was observed, but some of the⁷⁴As-DMA in the tissues was apparently in a complexed form.This work was performed within the framework of the contract of collaboration No. 1644-81-10 TS ISP S between the Commission of the European Communities and the National Institute of Environmental Medicine, Stockholm     

Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin administered to pregnant rats during the preimplantation period

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was given by gavage to pregnant rats on the 1st–3rd days of gestation in dosages of 0 (control), 0.125, 0.5, and 2 μg/kg/day. The treatment did not increase pre- and postimplantation losses. Mean fetal weight was reduced at the 0.5 and 2 μg/kg dose levels.     

Sex Differences in Recovery from Aphasia

The influence of sex on recovery from aphasia was investigated for oral expression and auditory verbal comprehension separately in 264 males and 121 females subdivided according to presence/absence of rehabilitation. The conclusions were that females recover significantly better than males in oral expression, but not in auditory verbal comprehension.These results are discussed with regard to the possible existence of a different cerebral organization in males and females.     

GM1 ganglioside therapy in acute ischemic stroke. Italian Acute Stroke Study--Hemodilution + Drug

Eleven of 31 clinical centers participating in the Italian Acute Stroke Study--Hemodilution carried out a preliminary study on the effectiveness of ganglioside GM1 in acute stroke; 502 patients were randomized to GM1 (GM1, n = 121), GM1 plus hemodilution (GM1 + H, n = 128), placebo (P, n = 130), or placebo plus hemodilution (P + H, n = 123) groups less than or equal to 12 hours after onset of a hemispheric cerebral infarct. The patients were treated for 15 days and were evaluated on Days 21 and 120 after the onset of stroke. Intention-to-treat analysis failed to show any differences in neurologic deficit, mortality, or neurologic disability among the groups. Efficacy analysis showed a significantly higher degree of neurologic improvement in GM1 group patients compared with patients in the P group during the first 15 days. GM1-treated patients (GM1 and GM1 + H groups) showed a significantly higher degree of neurologic improvement during the first 10 days compared with the placebo-treated patients (P and P + H groups). These differences were no longer statistically significant at Day 120. Our results provide a rationale for the planning of a larger, multicenter trial of GM1 ganglioside in acute stroke.