A nested case-control study was conducted in Washington County, MD, to determine whether low serum micronutrients are related to the subsequent risk of cervical cancer. Among the 15,161 women who ...donated blood for future cancer research during a serum collection campaign in 1974, 18 developed invasive cervical cancer and 32 developed carcinoma in situ during the period January 1975 through May 1990. For each of these 50 cases, two matched controls were selected from the same cohort. The frozen sera of the cases and their matched controls were analyzed for a number of nutrients. The mean serum levels of total carotenoids, alpha-carotene, beta-carotene, cryptoxanthin, and lycopene were lower among cases than they were among controls. When examined by tertiles, the risk of cervical cancer was significantly higher among women in the lower tertiles of total carotenoids (odds ratio 2.7; 95% confidence limit, 1.1-6.4), alpha-carotene (odds ratio, 3.1; 95% confidence limit, 1.3-7.6), and beta-carotene (odds ratio, 3.1; 95% confidence limit, 1.2-8.1) as compared to women in the upper tertiles and the trends were statistically significant. Cryptoxanthin was significantly associated with a lower risk of cervical cancer when examined as a continuous variable. Retinol, lutein, alpha- and gamma-tocopherol, and selenium were not related to cervical cancer risk. Smoking was also strongly associated with cervical cancer. These findings are suggestive of a protective role for total carotenoids, alpha-carotene and beta-carotene in cervical carcinogenesis and possibly for cryptoxanthin and lycopene as well.
Based on the integrated chemostratigraphic and lithostratigraphic studies, as well as biostratigraphic and palaeoecological analyses of conodonts in the Ledai-179 core, we present a combined model of ...change in the upper Wenlock and lowermost Ludlow strata of the inner shelf settings in the eastern part of the Baltic Basin. The comparison of the delta super( 13)C trend, and conodont and lithological successions confirms previous suggestions that the Bir?tonas and Neve?is formations correspond to the Homerian. This is quite unexpected, however, that the chronostratigraphic position of the ?irvinta Formation changed from the Gorstian to the upper part of the Homerian. The numerical biostratigraphic changepoint analyses of local conodont richness, per capita immigration and also per capita extirpation rates revealed several episodes of permanent change. These episodes of dynamic states either preceded or postdated the Mulde extinction interval at the beginning of the late Homerian delta super( 13)C excursion, which points to possible transient effects of this extinction event on conodonts.
The exact pathogenesis of liver injury and fibrosis in chronic hepatitis C (CHC) is unclear. Free radicals play a role in CHC liver damage. Antioxidants (AO) (enzymatic and nonenzymatic) scavenge ...free radicals and prevent tissue injury. The aims of our study were to estimate serum levels of malondialdehyde (MDA), serum and liver levels of nonenzymatic fat-soluble AO, and to correlate the liver AO levels with the degree of inflammation and fibrosis on biopsy.
AO levels were estimated by high-pressure liquid chromatography in the pretreatment serum and liver biopsy specimen of 20 treatment-naïve patients with CHC who were not on vitamin supplements. Serum levels of MDA were measured as a marker of increased oxidative stress. Twenty-two healthy individuals with no history of vitamin supplementation served as controls. AO analyzed were: retinol, alpha- and gamma-tocopherol, lutein, beta-cryptoxanthin, lycopene, and alpha- and beta-carotene.
Twenty CHC patients (11 men, nine women, mean age 48.5 +/- 7.9 yr) were studied. Patients and controls were comparable in age and sex. Serum MDA levels were significantly higher in CHC patients compared with controls (1.62 +/- 0.57 vs 0.23 +/- 0.15 micromol/L, p = < 0.0000). Serum levels of all AO except lutein were significantly decreased in CHC patients, and their levels were two to ten times lower than serum levels in controls. Liver levels of alpha-carotene (p = 0.0004), beta-carotene (p = 0.006), and lutein (p = 0.002) correlated with the serum levels, whereas the levels of retinol, alpha-tocopherol, lycopene, and beta-cryptoxanthin showed no correlation. Serum MDA levels were significantly higher in patients with moderate-to-severe inflammation or fibrosis compared with those with mild inflammation or fibrosis. The levels of all liver AO except alpha-carotene were significantly lower in patients with moderate-to-severe fibrosis. The severity of inflammation (portal or lobular) did not affect liver AO levels.
Our findings suggest that increased oxidative stress is present in patients with CHC. Micronutrient AO are severely depleted in serum and liver tissue of patients with CHC, and liver levels of some AO appear to reflect serum levels. Increasing fibrosis is associated with decreased liver AO levels indicating that severe disease may be a consequence of AO depletion or decreased liver storage resulting from fibrosis.
Differences in lung cancer risk by race/ethnicity have been observed among smokers. To determine whether these observations might reflect differences in the formation of carcinogen-DNA adducts, we ...analysed blood specimens (n =151) collected from smokers who were recruited for possible participation in an antioxidant vitamin intervention study. Mononuclear cells were analysed for polycyclic aromatic hydrocarbon (PAH)-DNA adducts by competitive enzyme-linked immunosorbent assay. Genotypes of glutathione S-transferase M1 and P1 (GSTM1 and GSTP1), enzymes involved in the detoxification of PAH metabolites, were determined by polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively. GSTM1 was present in 65 out of 88 (73.4%), 16 out of 32 (50.0%) and 16 out of 29 (54.8%) of African-Americans, Caucasians and Latinos, respectively (p =0.022). Homozygosity for the GSTP1 codon 105 variant was found in 25.6%, 6.3% and 10.0% of African-Americans, Caucasians and Latinos, respectively (p =0.023). Regression analysis of the log-transformed adduct levels confirmed that Caucasian and Latino subjects had lower PAH-DNA adduct levels than African-American subjects, after adjustment for gender, education,α -tocopherol and β-carotene levels, and GSTM1 status. Further adjustment for age and current smoking habits had no impact on these findings. Although crude analysis suggested that the GSTM1-positive genotype may be associated with lower PAH-DNA levels in Caucasians (but not in African-Americans or Latinos), a formal test for interaction between GSTM1 and ethnicity was not significant. We found no association between adduct levels and GSTP1 genotype. Although the mechanism is unclear, ethnic differences in DNA damage levels may in part explain why African-Americans have higher lung cancer incidence rates than other ethnic groups.
Oxidative stress in unilateral ureteral obstruction (UUO) contributes to the development of glomerular and tubulointerstitial lesions. The present study investigated whether oxidized low-density ...lipoprotein (oLDL) contributes to the pathogenesis of kidney injury in UUO, and whether alpha-tocopherol modulates such cytotoxicity and promotes repair. Male Sprague-Dawley rats weighing 100-125 g were assigned to three groups of 6 animals each: (1) sham, regular chow; (2) UUO, regular chow; and (3) UUO, alpha-tocopherol supplementation. We found a significant increase in the level of oxidative stress in the UUO group as measured by malondialdehyde (MDA) content in both plasma and kidneys. The LDL isolated from this group was cytotoxic to rat mesangial cells. The level of oxidation and cytotoxicity was significantly reduced when animals were treated with alpha-tocopherol. Plasma cholesterol concentration, kidney MDA, and transforming growth factor beta1 mRNA expression were all significantly increased in the UUO animals, and partially reduced in alpha-tocopherol-treated animals. Our data suggest that oxidative modification of LDL is associated with the renal injury in UUO. Taken together, our data support the concept that alpha-tocopherol can modulate LDL oxidation and its cytotoxic effects on rat mesangial cells in vitro.
Eine in den letzten Jahren entwickelte flexible Herstellungstechnologie für pyroelektrische Infrarotsensoren auf der Basis von Lithiumtantalat (LiTaO
) ermöglicht es, Sensoren zu entwerfen und zu ...fertigen, die einen hohen Signal-Rausch-Abstand besitzen und der geplanten Anwendung optimal angepasst sind. So wurden ultradünne, freitragende LiTaO
-Schichten mit einer Dicke von weniger als 1 μm hergestellt, mit denen die Sensoren eine spezifische Detektivität
von über
5×10
cm Hz
erreichen.
In recent years, a flexible technology has been developed for the manufacturing of pyroelectric infrared detectors based on lithium tantalate (LiTaO
allowing the fabrication of detectors with very high signal-to-noise ratios and their customization for particular applications. In this way, ultrathin self-supporting LiTaO
layers with film thicknesses of less than 1 μm have been manufactured for high-performance detectors with a maximum specific detectivity
of more than
5×10
cm Hz
W
Zusammenfassung
Eine in den letzten Jahren entwickelte flexible Herstellungstechnologie für pyroelektrische Infrarotsensoren auf der Basis von Lithiumtantalat (LiTaO
3
) ermöglicht es, Sensoren zu ...entwerfen und zu fertigen, die einen hohen Signal-Rausch-Abstand besitzen und der geplanten Anwendung optimal angepasst sind. So wurden ultradünne, freitragende LiTaO
3
-Schichten mit einer Dicke von weniger als 1 μm hergestellt, mit denen die Sensoren eine spezifische Detektivität
D
*
von über
5×10
9
cm Hz
1/2
W
-1
erreichen.
Abstract
In recent years, a flexible technology has been developed for the manufacturing of pyroelectric infrared detectors based on lithium tantalate (LiTaO
3
)
allowing the fabrication of detectors with very high signal-to-noise ratios and their customization for particular applications. In this way, ultrathin self-supporting LiTaO
3
layers with film thicknesses of less than 1 μm have been manufactured for high-performance detectors with a maximum specific detectivity
D
*
of more than
5×10
9
cm Hz
1/2
W
-1
.
The aim of the article is to present a developed algorithm of a stepped structural optimization method in the case of load combinations. The presentation of external loading via load combinations ...usually is employed in design codes. The pin‐jointed steel structures as light‐weight ones are widely used in actual engineering practice. The employment of dissipative features of material via elastic‐plastic model ensures a significant reduction of structural carrying capacity reserves (essential economic effect) versus the employment of structural response only in the elastic range. The stability, stiffness, constructional requirements and actual functions for cross‐sectional properties of standard profiles are employed in the optimization process aiming to obtain an optimal light‐weight structure which deformed behavior is compatible with codified requirements for such class of engineering structures. FEM mathematical models realizing structural optimization method steps are developed.
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