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  • 1
    ISSN: 1432-5241
    Keywords: Facial aging ; Oral implants ; Hydroxyapatite ; Facial skeletal augmentation ; Facial rejuvenation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Facial aging is almost exclusively a result of soft tissue changes in patients with full dentition. Loss of teeth can hasten facial aging and make aging more pronounced as a result of bony erosion of the alveolar ridges. This article describes these changes and demonstrates that properly selected oral implants and precisely placed hydroxyapatite implants can integrate with facelifts to produce superior facial rejuvenation in edentulous patients.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Short (5 days)-to long-term (4 months) corticosterone (CORT) administration by injection, pellet implantation, or in the drinking water decreased glial fibrillary acidic protein (GFAP) by 20–40% in hippocampus and cortex of intact rats. In contrast to CORT, adrenalectomy (ADX) caused elevations (50–125%) in hippocampus and cortex GFAP within 12 days of surgery that persisted for at least 4 months. CORT replacement of ADX rats decreased GFAP amount in hippocampus and cortex. The effects of long-term CORT and ADX on GFAP in hippocampus and cortex were also seen in striatum, midbrain, and cerebellum, findings suggestive of brain-wide adrenal steroid regulation of this astrocyte protein. The changes in GFAP amount due to CORT and ADX were paralleled by changes in GFAP mRNA, indicating a possible transcriptional or at least genomic effect of adrenal steroids. Glucocorticoid regulation of GFAP was relatively specific; it could not be generalized to other astrocyte proteins or other major structural proteins of neurons. The negative regulation of GFAP and GFAP mRNA by adrenal steroids suggested that increases in GFAP that result from brain injury may be attenuated by glucocorticoids. However, chronic CORT treatment of intact rats did not reverse or reduce the large increases in GFAP caused by trauma-or toxicant-induced brain damage. Thus, glucocorticoids and injury appear to regulate the expression of GFAP through different mechanisms. In contrast to the lack of effects of CORT on brain damage-induced increases in GFAP, CORT treatment begun in 2-week ADX rats, after an increase in GFAP had time to occur, did reverse the ADX-induced increase in GFAP. These results suggest that the increase in GFAP resulting from ADX is not mediated through an injury-linked mechanism.
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  • 3
    ISSN: 1360-0443
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Nitrous oxide is commonly used (abused) recreationally by inhaling it in a bolus form (i.e. single or several breaths). The time course of the psychoactive effects of nitrous oxide, via this mode of inhalation, has not been adequately characterized and thus formed the basis for this study. Twelve healthy volunteers participated in four sessions, using a randomized, cross-over, placebo-controlled design. In each session one of the following four measures were assessed: self-reported strength of drug effects, mood, memory and psyckomotor performance. Within sessions, subjects were exposed to four different concentrations of nitrous oxide in a randomized fashion: 0% (oxygen-placebo), 40%, 60% and 80%. At each concentration, or “trial”, subjects took four deep breaths of the gas. Peak drug effects, as reported by our subjects, occurred within 30 seconds after the last inhalation of nitrous oxide, persisted for about a minute, and then gradually subsided to near-baseline levels by 5 minutes post-inhalation. Certain aspects of mood were briefly affected by nitrous oxide, generally in a dose-related fashion with increases in visual analog scale ratings of “anxious”, “stimulated”, “coasting (spaced out)”, “lightheaded”, “confused”, and “high”. Free recall of words that had been presented between 30 and 60 seconds post-inhalation was significantly reduced after 80% nitrous oxide, relative to oxygen-placebo. There was a trend towards psychomotor impairment (Concentration x time: p – 0.08), as measured by the Digit Symbol Substitution Test, with peak decrements in performance (about a minute after inhalation) being greater after 80% nitrous oxide than after 0% nitrous oxide. Our results suggest that there arc acute, albeit brief, adverse effects of inhaling bolus concentrations of nitrous oxide.
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  • 4
    ISSN: 1442-2042
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Clinical characteristics of prostate cancer patients were anatyzed to compare the rates of progression of prostate cancer between patients in Japan (Gunma Urological Oncology Study Group: GUOSG) and the USA (Roswell Park Cancer Institute: RPCI), between 1980 and 1989. The stage of disease was more advanced and the age was greater in GUOSG patients compared with RPCI patients. However, the prostate cancer death rate of stage D patients at RPCI was significantly higher than that of the GUOSG. Moreover, the survival rate of stage A patients in the GUOSG was better than that of RPCI patients. The possibility of biases which may affect both the clinical characteristics and survival rates in the 2 populations studied is discussed. To determine whether there is a real difference in the rate of prostate cancer growth between the 2 countries will require a prospective study, ideally conducted in large population groups.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Communications in mathematical physics 164 (1994), S. 351-384 
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract This article investigates the limiting behavior of a diffusion in a half space with a complicated boundary condition. The boundary condition implements a reflection condition everywhere except a number of small sets or “holes” that meet Dirichlet or mixed boundary conditions. Probabilistic methods associated with the Feynman-Kac formula are used to find the limiting behavior of the diffusion equations as the number of holes gets large and the size of each hole is reduced. With particular scaling homogenization occurs, and we see that the complicated boundary condition is replaced by a simple mixed boundary condition depending on the capacitance and distribution of the holes.
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  • 6
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-072X
    Keywords: Biodegradation ; Nitropolycyclic aromatic hydrocarbons ; Aerobic ; Anaerobic ; Mycobacterium ; 1-Nitropyrene ; cis-Dihydrodiols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The metabolism of 14C-labeled 1-nitropyrene in microcosms containing nonsterile estuarine sediments, and in cultures of a Mycobacterium sp. previously isolated from oil-contaminated sediments was investigated. Although mineralization of 1-nitropyrene by pure cultures of the Mycobacterium sp. totaled only 12.3% after 10 days of incubation, over 80% of the ethyl acetate extractable 14C-labeled compounds consisted of 1-nitropyrene metabolites. High pressure liquid chromatographic analysis of 1-nitropyrene degradation products indicated that two major metabolites were formed. They were identified as 1-nitropyrene cis-9,10-and 4,5-dihydrodiols, based on their UV-visible, mass and NMR spectra. Time course studies in microcosms showed that 1-nitropyrene was degraded slowly under aerobic and anaerobic conditions in estuarine sediments. Less than 1% had been converted to 14CO2 after 8 weeks of aerobic incubation. The addition of 1-nitropyrene to anaerobic sediments resulted in no 14CO2 evolution; however, the nitro group of 1-nitropyrene was reduced to form 1-aminopyrene. Although the mineralization of 1-nitropyrene in sediments was slow, the Mycobacterium sp. metabolized 1-nitropyrene in pure culture. This bacterium appears promising for the bioremediation of this ubiquitous pollutant in contaminated waste.
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  • 8
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Cytochrome P-450 ; Dihydrodiol ; K-region ; Metabolism ; Phenanthrene ; Polycyclic aromatic hydrocarbons ; Streptomyces flavovirens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The metabolism of phenanthrene, a polycyclic aromatic hydrocarbon (PAH), by Streptomyces flavovirens was investigated. When grown for 72 h in tryptone yeast extract broth saturated with phenanthrene, the actinomycete oxidized 21.3% of the hydrocarbon at the K-region to form trans-9,10-dihydroxy-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol). A trace of 9-phenanthrol was also detected. Metabolites isolated by thin-layer and high performance liquid chromatography were identified by comparing chromatographic, mass spectral, and nuclear magnetic resonance properties with those of authentic compounds. Experiments using [9-14C]phenanthrene showed that the trans-9,10-dihydrodiol had 62.8% of the radioactivity found in the metabolites. Circular dichroism spectra of the phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was (−)-9S,10S, the same as that of the principal enantiomer produced by mammalian enzymes. Incubation of S. flavovirens with phenanthrene is an atmosphere of 18O2, followed by gas chromatographic/mass spectral analysis of the metabolites, indicated that one atom from molecular oxygen was incorporated into each molecule of the phenanthrene trans-9,10-dihydrodiol. Cytochrome P-450 was detected in 105,000×g supernatants prepared from cell extracts of S. flavovirens. The results show that the oxidation of phenanthrene by S. flavovirens was both regio- and stereospecific.
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  • 9
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Fish-eating waterbirds from the Great Lakes of North America have shown symptoms of poisoning similar to those observed in laboratory exposures of various avian species to planar halogenated hydrocarbons (PHHs). PHHs, include among others, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) and have been implicated in some of the reproductive problems of Great Lakes waterbirds. The objectives of this study were to assess the overall potencies of PCB-containing extracts from colonial water-bird eggs taken from the Great Lakes and to compare the potencies with the location and spatial distribution of the colonies. The potencies of the extracts were assessed by their ability to induce cytochrome P450IA1-associated ethoxyresorufin O-deethylase (EROD) activity in H4IIE rat hepatoma cells as compared to the standard, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The H4IIE bioassay-derived TCDD-equivalents (TCCD-EQs) in the waterbird eggs concur with residue analyses and biological data from other studies. The greatest concentrations of TCDD-EQs were found in waterbird eggs from historically polluted, industrialized or urbanized areas in which the reproductive impairment of colonial waterbirds was most severe. However, significant concentrations of TCDD-EQs were detected at all sites tested; with a range of 49 to 415 pg TCDD-EQ/g egg, uncorrected for extraction efficiencies. The H4IIE bioassay proved to be a useful biomonitoring tool to assess the overall potency of complex PHH mixtures in environmental samples.
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  • 10
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The possible diurnal variation in cardiac [Ca2++ Mg2+]-dependent ATPase (Ca2+ pump) activity and the influence of pinealectomy and melatonin on this enzyme in rat heart have been studied. Lowest levels of cardiac sarcolemma] membrane [Ca2++ Mg2+]-dependent ATPase activity were measured in late afternoon in rats kept under a 14:10 light:dark cycle. Late in the dark phase the enzyme activity began to increase with the rise continuing until 0900, 3 hr after light onset. These time-dependent changes in [Ca2++ Mg2+]-dependent ATPase activity did not occur in either pinealectomized or light-exposed rats suggesting that melatonin, secreted from the pineal gland during the night, induces the change in [Ca2++ Mg2+]-dependent ATPase activity. In vitro studies in which cardiac tissue was incubated in the presence of melatonin over a wide range of doses showed that this indole stimulated the Ca2+ pump. The half-maximal effect of melatonin was observed at a melatonin concentration of 28 ng/ml. These findings suggest that the daily change in [Ca2++ Mg2+]-dependent ATPase activity in the sarcolemma of heart tissue is a result of the circadian rhythm in pineal melatonin production and secretion. These findings may be applicable to normal cardiac physiology.
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