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31.
R Middendorff D Müller S Wichers AF Holstein MS Davidoff 《Canadian Metallurgical Quarterly》1997,82(12):4154-4161
Previous studies have demonstrated that nitric oxide (NO) influences Leydig cell function. Here we provide evidence for NO production and activity in seminiferous tubules and blood vessels of the human testis. By immunohistochemistry, the soluble guanylyl cyclase (sGC), the intracellular NO receptor, and the second messenger, cyclic guanosine monophosphate (cGMP), were detected in myofibroblasts of the peritubular lamina propria in Sertoli cells, as well as in endothelial and smooth muscle cells of testicular blood vessels. Performed with isolated tubules and blood vessels, the biological activity of sGC could be proved by cGMP generation in response to treatments with the NO donor, sodium nitroprusside. The endothelial and neuronal subtypes of NO synthase (NOS) were localized immunohistochemically to the same cell types that express sGC and cGMP. In isolated tubules and vessels, the presence of endothelial NOS and neuronal NOS was confirmed by immunoblotting, and NOS activity was demonstrated by decreased cGMP production upon incubation with the NOS inhibitor L-nitro arginine methylester. These findings show that peritubular cells, Sertoli cells, and testicular blood vessels may be sites of NO production and activity, possibly involved in relaxation of seminiferous tubules and blood vessels to modulate sperm transport and testicular blood flow, respectively. 相似文献
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J Müller-Ehmsen K Brixius C Schulze RH Schwinger 《Canadian Metallurgical Quarterly》1997,355(6):727-732
Insect cell lines in culture are used for a variety of studies. In this laboratory imaginal disc cell lines have been established from primary cultures from third instar larvae, and used for a number of experiments. The effect of ageing on the morphology and physiology of Drosophila cell lines has received very little attention, although problems of genotypic or phenotypic changes in cell lines with age are recognized in other areas of animal cell culture. We tested our cell line Cl8+ for any difference in growth, morphology and response to 20-hydroxyecdysone (20HE) at different ages (passage numbers). The cells were found to multiply faster, adhere less firmly to the substrate and to lose the tendency to aggregate at higher passages. The response to 20HE in terms of cell numbers and induction of beta-galactosidase was similar at all passage numbers but morphological changes in hormone-treated cells were less obvious in the higher passages. Cell lines are likely to vary in the extent of ageing effects but workers are advised to be aware of the possibilities. We suggest the effects of age on cell lines should be established, and passage numbers noted in experimental reports. 相似文献
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Blood flow is a critical parameter for obtaining satisfactory temperature distributions during clinical hyperthermia. This study examines the changes in blood flow distribution in normal porcine skeletal muscle before, during and after a period of regional microwave hyperthermia. The baseline blood flow distribution during general anaesthesia and after the insertion of the thermal probes was established independently in order to isolate the changes due to hyperthermia. General anaesthesia alone and thermocouple insertion during anesthesia had no significant effect on the muscle blood flow distribution. Regional microwave heating generated a non-uniform blood flow distribution which was a function of the tissue temperature distribution. Blood flow was greater in those tissues samples in which higher temperatures were recorded and less in those sampled further from the applicators peak SAR (Specific Absorption Rate). The increase in blood flow appears to be primarily a local phenomenon. Although muscle blood flow may be considered to be uniform prior to heating, this does not hold during hyperthermia treatment. Therefore, the non-uniform nature of the blood distribution during heating should be incorporated into any practical bioheat transfer model. 相似文献
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37.
R Kürzl 《Canadian Metallurgical Quarterly》1993,53(1):15-19
OBJECTIVE: To analyze HLA-DR4 alleles in New Zealand Polynesians with rheumatoid arthritis (RA). METHODS: Thirty Polynesians and 30 Caucasians with RA, as well as 65 Polynesian and 60 Caucasian healthy blood donors, were DR4 subtyped using the polymerase chain reaction and sequence-specific oligonucleotide probes. RESULTS: The frequency of DR4 (DRB1*04) was increased in both Polynesian (P < 0.001) and Caucasian (P < 0.005) RA patients compared with race-matched controls. Dw4 (DRB1*0401) was detected in 15 of 30 Caucasian patients but only 2 of 30 Polynesian patients (P < 0.001). In Polynesians, RA was associated with Dw15 (DRB1*0405), which was present in 11 of 30 patients and 3 of 65 controls (P < 0.001). Dw13 (DRB1*0403) was the most frequent DR4 allele in healthy Polynesians, but was not significantly associated with RA. CONCLUSION: The predominance of the Dw13 subtype in Polynesians may explain in part the low prevalence of RA in this population. The association of Dw15 with RA in Polynesians supports the hypothesis that the third hypervariable region of DR beta determines susceptibility to RA. 相似文献
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39.
2-Hydroxy-5-methyllaurophenone oxime (FLM 5011) is an inhibitor of lipoxygenase with antiinflammatory and antiallergic actions. We incubated FLM 5011 on the human immortal cell line Hep G2 and found a similar metabolite spectrum as in rat urine and faeces. We also measured the cytotoxicity of FLM 5011 on Hep G2 monolayers by the amido black assay and found that the influence of cell proliferation is partly due to apoptotic activities. Although the metabolic activity of Hep G2 cells is lower compared to rat hepatocyte cultures they are a suitable test system for biotransformation studies. Their higher proliferation rate allows toxicity to be characterised more exactly. 相似文献
40.
AO Güre NK Altorki E Stockert MJ Scanlan LJ Old YT Chen 《Canadian Metallurgical Quarterly》1998,58(5):1034-1041
Supplementation with high doses of alpha-tocopherol has increased the oxidation resistance of LDL in many clinical trials. There have been only a few placebo-controlled trials in healthy persons of alpha-tocopherol doses usually contained in dietary supplements. We carried out a single-blind, placebo-controlled, randomized trial to examine the effect of 200 mg RRR-alpha-tocopheryl acetate/d on the oxidation resistance of atherogenic lipoproteins (VLDL+LDL including intermediate-density lipoproteins) in 40 smoking men. VLDL+LDL oxidation resistance was assessed as conjugated dienes after copper induction and hemin degradation after hydrogen peroxide induction. Also, the LDL total peroxyl-radical trapping antioxidant parameter (LDL TRAP) and plasma malondialdehyde were measured at baseline and after 2 mo of supplementation. Plasma RRR-alpha-tocopherol concentrations were measured at 2-h intervals for 12 h at baseline and after 2 mo of supplementation. Compared with placebo, 200-mg RRR-alpha-tocopheryl acetate supplementation elevated plasma and VLDL+LDL alpha-tocopherol concentrations, LDL TRAP, and oxidation resistance of VLDL+LDL. Plasma alpha-tocopherol increased by 88% (P < 0.0001), VLDL+LDL alpha-tocopherol increased by 90% (P < 0.0001), and LDL TRAP by 58% (P < 0.0001). The time to the start of oxidation (lag time) was prolonged by 34% when assessed with a copper-induced method and by 109% when assessed with a hemin + hydrogen peroxide-induced method; the time to maximal oxidation was prolonged by 21% (copper-induced method) in the vitamin E-supplemented group. Changes in plasma alpha-tocopherol, lipid-standardized alpha-tocopherol, and VLDL+LDL alpha-tocopherol correlated significantly with changes in LDL TRAP, lag time, and time to maximal oxidation. Differences in changes between groups in the area under the curve for plasma alpha-tocopherol were significant (P < 0.009). Our results suggest that 200 mg oral RRR-alpha-tocopheryl acetate/d had a clear effect on the in vitro oxidation of VLDL+LDL in smoking men. 相似文献