Inverse relationship of epidermal growth factor receptor and HER2/neu gene expression in human renal cell carcinoma

Expression of the oncogenes, epidermal growth factor (EGF) receptor, HER2/neu, c-myc, and c-fos, in renal cell carcinoma and corresponding nonneoplastic kidney tissue of 30 patients has been analyzed by Northern blot analysis. In renal cell carcinoma an inverse relationship of EGF receptor and HER2/neu gene expression was detected, with high expression of the EGF receptor gene in 22 of 30 (73%) cases and low expression of the HER2/neu gene in 28 of 30 (93%) cases. Furthermore, altered expression of the oncogenes c-myc and c-fos was detected in renal cell carcinoma, which appears to be related to the tumor grade of malignancy. Additional Southern blot analysis of six renal cell carcinomas gave no indication of chromosomal rearrangement events or gene amplification.     

Supplementation with beta-carotene or a similar amount of mixed carotenoids protects humans from UV-induced erythema

Carotenoids are useful oral sun protectants, and supplementation with high doses of beta-carotene protects against UV-induced erythema formation. We compared the erythema-protective effect of beta-carotene (24 mg/d from an algal source) to that of 24 mg/d of a carotenoid mix consisting of the three main dietary carotenoids, beta-carotene, lutein and lycopene (8 mg/d each). In a placebo-controlled, parallel study design, volunteers with skin type II (n = 12 in each group) received beta-carotene, the carotenoid mix or placebo for 12 wk. Carotenoid levels in serum and skin (palm of the hand), as well as erythema intensity before and 24 h after irradiation with a solar light simulator were measured at baseline and after 6 and 12 wk of treatment. Serum beta-carotene concentration increased three- to fourfold (P < 0.001) in the beta-carotene group, whereas in the mixed carotenoid group, the serum concentration of each of the three carotenoids increased one- to threefold (P < 0.001). No changes occurred in the control group. The intake of either beta-carotene or a mixture of carotenoids similarly increased total carotenoids in skin from wk 0 to wk 12. No changes in total carotenoids in skin occurred in the control group. The intensity of erythema 24 h after irradiation was diminished in both groups that received carotenoids and was significantly lower than baseline after 12 wk of supplementation. Long-term supplementation for 12 wk with 24 mg/d of a carotenoid mix supplying similar amounts of beta-carotene, lutein and lycopene ameliorates UV-induced erythema in humans; the effect is comparable to daily treatment with 24 mg of beta-carotene alone.     

Representative studies of the vitamin D status of 2-year-old children in Frankfurt am Main

In a representative sample population of 421 two-year-old Frankfurt children studied for vitamin-D nutritional status, only one case of subclinical rickets was discovered. 93.3% of the children have been a regular vitamin-D supplements during the first 12 month of life, but only 32.7% of them continued to receive the supplement beyond the age of one year. Risk groups were not identified, neither with regard to ethnic groups, nor smaller vitamin-D doses, or any other aspect.     

Effect of atorvastatin on plasma levels of asymmetric dimethylarginine in patients with non-ischaemic heart failure

BACKGROUND: Elevated plasma levels of asymmetric dimethylarginine (ADMA), an endothelial nitric oxide synthase (eNOS) inhibitor, may contribute to endothelial dysfunction in chronic heart failure (CHF). Since statins upregulate eNOS and ameliorate endothelial dysfunction in non-ischaemic CHF, we hypothesized that this may be in part through modification of ADMA. AIM: To evaluate the effect of atorvastatin on the relationship between ADMA and endothelial function in non-ischaemic CHF. METHODS: Twenty-four patients with CHF (ejection fraction <40%, New York Heart Association Functional Classes II and III) were randomised to atorvastatin treatment (40 mg) or placebo once daily for 6 weeks in a double-blinded, placebo-controlled crossover study. Plasma ADMA and l-arginine levels were measured by HPLC. Endothelial function was assessed by flow-mediated dilatation and invasive forearm plethysmography. RESULTS: Post-statin therapy, endothelial function was improved (p<0.05) independent of LDL-cholesterol reductions, but no changes were observed in ADMA levels or the l-arginine to ADMA ratio. There was a trend for ADMA to inversely correlate with endothelial function at baseline. CONCLUSIONS: Short-term atorvastatin treatment in non-ischaemic CHF improves endothelial function but has no effect on ADMA or the l-arginine to ADMA ratio. Our finding suggests that the observed statin-induced improvements in endothelial function are likely mediated via alternative pathways.     

Cytochrome P-450, reductive metabolism, and cell injury

A variety of organic compounds such as carbon tetrachloride, halothane, gentian violet, and benznidazole are reductively metabolized to free radicals by liver microsomal cytochrome P-450. Due to the fact that this metabolic activation occurs at a site where O2 usually becomes activated during the monooxygenase cycle, there is a competition between these xenobiotics and O2 for electrons. Reductive activation occurs at a maximal rate under anaerobic conditions. Cell injury may be directly produced by the reactive metabolites. It may also result from lipid peroxidation induced by interaction of the free radicals with polyunsaturated fatty acids of membrane phospholipids. For polyhalogenated alkanes the latter process is most likely the one leading to cell death. When loss of cell viability is mediated by lipid peroxidation, a complex O2 dependence may result, characterized by a maximum loss of cell viability at oxygen partial pressures (PO2) between 1 and 10 mm Hg. These PO2 values are found in the centrilobular area of the liver lobule.     

Antioxidant activity of the pyridoindole stobadine. Pulse radiolytic characterization of one-electron-oxidized stobadine and quenching of singlet molecular oxygen.

Antioxidant properties of stobadine, a pyridoindole derivative described to exhibit cardioprotective properties, were characterized. The radical scavenging potential of stobadine was evaluated using pulse radiolysis with optical detection, by which it is shown that one-electron oxidation of stobadine with radicals such as C6H5O., CCl3O2., Br2.-, and HO. (reaction rate constants approximately 5 x 10(8)-10(10) M-1 s-1) leads to the radical cation (absorbance maxima at 280 and 445 nm) which deprotonates from the indolic nitrogen (pKa = 5.0) to give a nitrogen-centered radical (absorbance maxima at 275, 335, and 410 nm), probably bearing a positive charge at the pyrido nitrogen. The radical of stobadine reacts with Trolox (i.e., 6-hydroxy-2,5,7,8-tetramethyl-chromane-2-carboxylic acid) with a rate constant of 1.2 x 10(7) M-1 s-1 at pH 7.0 by one-electron oxidation to yield the phenoxyl-type radical of Trolox. This reaction is reversible (k = 2 x 10(5) M-1 s-1). The redox potential of stobadine at pH 7 is 0.58 V/NHE. Stobadine is also a quencher of singlet molecular oxygen (1O2) with an overall quenching rate constant of 1.3 x 10(8) M-1 s-1, determined with the endoperoxide of 3,3'-(1,4-naphthylene)dipropionate (NDPO2) as 1O2 source and by monitoring 1O2 photoemission with a germanium diode.     

A novel biologically active selenooorganic compound--VII. Biotransformation of ebselen in perfused rat liver

Ebselen (PZ 51) is a selenoorganic compound with antioxidant and antiinflammatory properties, and its metabolism was studied in isolated perfused rat liver (hemoglobin-free, open system). 75Se-labelled ebselen was taken up into liver cells and radioactivity was excreted into bile. Biliary excretion of 75Se-compounds reached maximal values of 4 nmol/min per g wet wt. HPLC analysis of bile and effluent perfusate as well as identification of separated metabolites by mass spectrometry were carried out. The biliary metabolites were (a) an interesting novel Se-glucuronide, 2-glucuronylselenobenzanilide, (metabolite IV), as the major metabolite, and (b) an O-glucuronide, N-(4'-glucuronyloxyphenyl)-2-methylselenobenzanilide (metabolite III). The major effluent perfusate metabolites were Se-methylated derivatives (metabolites I and II). There was no evidence for sulfated metabolites. The selenodisulfide with glutathione, S-(2-phenyl-carbamoyl-phenylselenyl)-glutathione, was not detected, probably because of low steady-state concentrations and/or its biochemical lability. The selenium in ebselen is not bioavailable (e.g. for the synthesis of glutathione peroxidase), in contrast to selenite, for example, thus explaining the very low ebselen toxicity. However, the enzymatic steps in Se-methylation could be similar to those in the metabolism of selenite which include hydrogen selenide methylation. Se-glucuronides constitute a novel category of compounds in addition to the O-, N-, C- and S-glucuronide classes known in biology.     

Identification and quantitation of glutathione in hepatic protein mixed disulfides and its relationship to glutathione disulfide

The amount of glutathione present in hepatic protein mixed disulfides was determined to be 20–30 nmole/g liver. This was established using two specific enzymatic methods: (a) the coupled assay with DTNB and glutathione (GSSG) reductase and (b) a newly developed test using GSH transferase and 1-chloro-2,4-dinitrobenzene for the estimation of GSH released from proteins after borohydride treatment; further, these results were confirmed by HPLC analysis. Thus, authentic glutathione makes up only 2–6% of the value for total protein mixed disulfides. The latter were determined with the generally employed o-phthalaldehyde assay, which is not necessarily specific for GSH. The amount of glutathione mixed disulfides depends linearly on the content of glutathione disulfide in the liver cell in the range studied. By increasing the GSSG levels from 20 to about 60 nmole/g liver with paraquat, nitrofurantoin or t-butyl hydroperoxide, glutathione protein mixed disulfides are increased by a similar amount.