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1.
Hawkes WC Richter BD Alkan Z Souza EC Derricote M Mackey BE Bonnel EL 《Biological trace element research》2008,122(2):107-121
The essential nutrient selenium is required in microgram amounts [recommended dietary allowance (RDA) = 55 μg/day, 699 nmol/day]
and has a narrow margin of safety (upper tolerable intake limit = 400 μg/day, 5 μmol/day). We conducted a randomized placebo-controlled
study of high-selenium yeast, the form used in most supplements (300 μg/day, 3.8 μmol/day), administered to 42 free-living
healthy men for 48 weeks. Dietary intakes of selenium, macronutrients, and micronutrients were not different between groups
and did not change during the study. Supplementation more than doubled urinary selenium excretion from 69 to 160 μg/day (876
to 2,032 nmol/day). Urinary excretion was correlated with recent selenium intake estimated from 3-day diet records: urinary
selenium excretion = 42 μg/day (533 nmol/day) + 0.132 × dietary selenium intake, p < 0.001. Dietary selenium intake was not significantly correlated with the other indicators of selenium status, presumably
because urinary selenium excretion reflected recent intake, and tissue selenium was homeostatically controlled. After 48 weeks
of supplementation, plasma selenium was increased 60% from 142 to 228 μg/l (1.8 to 2.9 μmol/l), and erythrocyte selenium was
approximately doubled from 261 to 524 μg/l (3.3 to 6.6 μmol/l). Selenium concentrations increased more modestly in hair (56%)
and platelets (42%). Platelets were the only blood component in which glutathione peroxidase activity was significantly related
to selenium content. Selenium levels decreased rapidly after the end of supplementation, and there were no significant differences
in selenium status indicators between groups by week 96. The absorption, distribution, and excretion of selenium from high-Se
yeast were similar to selenium in foods. 相似文献
2.
Cometabolic biodegradation of methyl t-butyl ether by Pseudomonas aeruginosa grown on pentane 总被引:1,自引:0,他引:1
A bacterial strain identified as Pseudomonas aeruginosa was isolated from a soil consortium able to mineralize pentane. P. aeruginosa could metabolize methyl t-butyl ether (MTBE) in the presence of pentane as the sole carbon and energy source. The carbon balance for this strain, grown
on pentane, was established in order to determine the fate of pentane and the growth yield (0.9 g biomass/g pentane). An inhibition
model for P. aeruginosa grown on pentane was proposed. Pentane had an inhibitory effect on growth of P. aeruginosa, even at a concentration as low as 85 μg/l. This resulted in the calculation of the following kinetic parameters (μmax = 0.19 h−1, K
s = 2.9 μg/l, K
i = 3.5 mg/l). Finally a simple model of MTBE degradation was derived in order to predict the quantity of MTBE able to be degraded
in batch culture in the presence of pentane. This model depends only on two parameters: the concentrations of pentane and
MTBE.
Received: 16 July 1998 / Received revision: 11 November 1998 / Accepted 31 November 1998 相似文献
3.
Marques RC de Sousa AF do Monte SJ Oliveira FE do Nascimento Nogueira N Marreiro DN 《Biological trace element research》2007,120(1-3):11-18
Studies have evidenced that zinc metabolism is altered in presence of Down syndrome, and zinc seems to have a relationship
with the metabolic alterations usually present in this syndrome. In this work, the Zn-related nutritional status of adolescents
with Down syndrome was evaluated by means of biochemical parameters and diet. A case–control study was performed in a group
of adolescents with Down syndrome (n = 30) and a control group (n = 32), of both sexes, aged 10 to 19 years. Diet evaluation was accomplished by using a 3-day dietary record, and the analysis
was performed by the NutWin program, version 1.5. Antropometric measurements were performed for evaluation of body composition.
The Zn-related nutritional status of the groups was evaluated by means of zinc concentration determinations in plasma and
erythrocytes, and 24-h urinary zinc excretion, by using the method of atomic absorption spectroscopy. The diet of both groups
presented adequate concentrations of lipids, proteins, carbohydrates, and zinc. The mean values found for zinc concentration
in erythrocytes were 49.2 ± 8.5 μg Zn/g Hb for the Down syndrome group and 35.9 ± 6.1 μg Zn/g Hb for the control group (p = 0.001). The average values found for zinc concentration in plasma were 67.6 ± 25.6 μg/dL for the Down syndrome group and
68.9 ± 22.3 μg/dL for the control group. The mean values found for zinc concentration in urine were 244.3 ± 194.9 μg Zn/24 h
for the Down syndrome group and 200.3 ± 236.4 μg Zn/24 h for the control group. Assessment of body composition revealed overweight
(26.7%) and obesity (6.6%) in the Down syndrome group. In this study, patients with Down syndrome presented altered zinc levels
for some cellular compartments, and the average zinc concentrations were low in plasma and urine and elevated in erythrocytes. 相似文献
4.
The sialic acid/glycosaminoglycan ratio was determined in 35 coronary artery ectasia patients and 35 control subjects to determine
the possible role of fluoride in the etiology of the disease. The coronary artery ectasia patients and controls were selected
from subjects who underwent coronary angiography. The mean serum sialic acid level was significantly lower in patients with
coronary artery ectasia (CAE) than in controls (340.3 ± 28.6 vs. 427.0 ± 15.9 μg/mL, respectively; p < 0.001). The mean serum glycosaminoglycan level was significantly higher in patients with CAE than in controls (5,013.1 ± 158.6
vs. 3,833.6 ± 237.1 μg/mL, respectively; p < 0.001). The sialic acid/glycosaminoglycan ratio in patients with coronary artery ectasia was significantly lower than in
controls (0.068 ± 0.007 vs. 0.111 ± 0.005; p < 0.001). There was more than 38.7% reduction in this ratio in patients with CAE when compared with controls. We demonstrated
that chronic fluoride exposure has an important role in pathogenesis of coronary artery ectasia. 相似文献
5.
Rahman A Azad MA Hossain I Qusar MM Bari W Begum F Huq SM Hasnat A 《Biological trace element research》2009,127(2):102-108
The purpose of the study was to determine the concentration of trace elements present in scalp hair sample of schizophrenic
patients and to find out the relationship between trace elements level and nutritional status or socioeconomic factors. The
study was conducted among 30 schizophrenic male patients and 30 healthy male volunteers. Patients were recruited from Bangabandhu
Sheikh Mujib Medical University by random sampling. Hair trace element concentrations were determined by flame atomic absorption
spectroscopy and analyzed by independent t test, Pearson’s correlation analysis, regression analysis, and analysis of variance (ANOVA). Mn, Zn, Ca, Cu, and Cd concentrations
of schizophrenic patients were 3.8 ± 2.31 μg/gm, 171.6 ± 59.04 μg/gm, 396.23 ± 157.83 μg/gm, 15.40 ± 5.68 μg/gm, and 1.14 ± 0.89 μg/gm
of hair sample, while those of control subjects were 4.4 ± 2.32 μg/gm, 199.16 ± 27.85 μg/gm, 620.9 ± 181.55 μg/gm, 12.23 ± 4.56 μg/gm,
and 0.47 ± 0.32 μg/gm of hair sample, respectively. The hair concentration of Zn and Ca decreased significantly (p = 0.024; p = 0.000, respectively) and the concentration of Cu and Cd increased significantly (p = 0.021; p = 0.000, respectively) in schizophrenic patients while the concentration of Mn (p = 0.321) remain unchanged. Socioeconomic data reveals that most of the patients were poor, middle-aged and divorced. Mean
body mass indices (BMIs) of the control group (22.26 ± 1.91 kg/m2) and the patient group (20.42 ± 3.16 kg/m2) were within the normal range (18.5−25.0 kg/m2). Pearson’s correlation analysis suggested that only Ca concentration of patients had a significant positive correlation
with the BMI (r = 0.597; p = 0.000) which was further justified from the regression analysis (R
2 = 44%; t = 3.59; p = 0.002) and one-way ANOVA test (F = 3.62; p = 0.015). A significant decrease in the hair concentration of Zn and Ca as well as a significant increase in the hair concentration
of Cu and Cd in schizophrenic patients than that of its control group was observed which may provide prognostic tool for the
diagnosis and treatment of this disease. However, further work with larger population is suggested to examine the exact correlation
between trace element level and the degree of disorder. 相似文献
6.
Ersoy IH Koroglu BK Varol S Ersoy S Varol E Aylak F Tamer MN 《Biological trace element research》2011,143(2):619-624
Although there are many studies on effect of fluoride on trace elements in experimental animals, few studies exist on serum
trace elements levels in patients with endemic fluorosis. We aimed to determine the serum levels of trace elements including
serum copper (Cu), zinc (Zn), and serum levels of minerals including calcium (Ca), phosphorus (P), magnesium (Mg), sodium
(Na), potassium (K) in patients with endemic fluorosis. The study group consisted of 30 patients with endemic fluorosis (17
females, 13 males, mean age 33.53 ± 9.85 years). An age, gender, and body mass index matched 30 healthy volunteers comprised
control group (21 females, ten males with a mean age 33.93 ± 7.39 years). Urine fluoride levels of chronic fluorosis patients
were significantly higher than that of control subjects as expected (1.92 ± 0.10 mg/l vs. 0.41 ± 0.09 mg/l, respectively;
P < 0.001). Serum Cu levels (89.14 ± 16.77 μg/dL vs. 102.69 ± 25.04 μg/dL, respectively, P = 0.017), serum Zn levels (77.98 ± 20.58 μg/dL vs. 94.57 ± 35.87μg/dL, respectively, P = 0.032), and serum Mg levels (1.92 ± 0.18 mg/dL vs. 2.07 ± 0.31 mg/dL, respectively, p = 0.022) was significantly lower in chronic fluorosis patients than in controls. There were no statistically significant
differences between the fluorosis group and control group with respect to serum levels of Na, K, Ca, and P. We concluded that
chronic fluorosis is associated with reduced serum levels of Cu, Zn, and Mg. 相似文献
7.
Oze H Hirao M Ebina K Shi K Kawato Y Kaneshiro S Yoshikawa H Hashimoto J 《In vitro cellular & developmental biology. Animal》2012,48(2):123-130
Previous studies have demonstrated that oxygen environment is an important determinate factor of cell phenotypes and differentiation,
although factors which affect pericellular oxygen concentration (POC) in murine chondrogenic cell culture remain unidentified.
Oxygen concentrations in vivo were measured in rabbit musculoskeletal tissues, which were by far hypoxic compared to 20% O2 (ranging from 2.29 ± 1.16 to 4.36 ± 0.51%). Oxygen concentrations in murine chondrogenic cell (C3H10T1/2) culture medium
were monitored in different oxygen concentrations (20% or 5%) in the incubator and in different medium volumes (3,700 or 7,400 μl)
within 25-cm2 flasks. Chondrogenic differentiation was assessed by glycosaminoglycan production with quantitative evaluation of Alcian
blue staining in 12-well culture dishes. Expression of chondrogenic genes, aggrecan, and type II collagen α1, was examined
by quantitative real-time polymerase chain reaction. Oxygen concentrations in medium decreased accordingly with the depth
from medium surface, and POC at Day 6 was 18.99 ± 0.81% in 3,700-μl medium (1,480-μm depth) and 13.26 ± 0.23% in 7,400-μl
medium (2,960-μm depth) at 20% O2 in the incubator, which was 4.96 ± 0.08% (1,480-μm depth) and 2.83 ± 0.42% (2,960-μm depth) at 5% O2, respectively. The differences of POC compared by medium volume were statistically significant (p = 0.0003 at 20% and p = 0.001 at 5%). Glycosaminoglycan production and aggrecan gene expression were most promoted when cultured in moderately
low POC, 1,000 μl (2,960-μm depth) at 20% O2 and 500 μl (1,480-μm depth) at 5% O2 in 12-well culture dishes. We demonstrate that medium volume and oxygen concentration in the incubator affect not only POC
but also chondrogenic differentiation. 相似文献
8.
The presence of hexavalent chromium salt in culture medium negatively affected the growth dynamics and physiological parameters
of the benthic microalga Attheya ussurensis. After 1 day of exposure to toxicant at concentrations of 2, 4, 7, and 10 mg/l, the cell counts were 10, 7.9, 5.6, and 4.3
× 103 cells/ml, respectively (versus 13 × 103 cells/ml in the control). A tendency towards a decrease in cell number remained until the end of the experiments; after 7
days of exposure the cell counts were 133, 102, 11, and 7.5 × 103 cells/ml (versus 204 × 103 cells/ml in the control). With increase in potassium bichromate concentration in the culture medium, there was an increase
in the ratio of cell height to width and a change in the form of the cell to horseshoe shaped. The contents of chlorophyll
a in microalgal cells after 1 day of exposure to 2, 4, 7, and 10 mg/l were 40, 37, 34, and 30 μg/l, respectively (45 μg/l in
the control). After 7 days, at chromium salt concentrations of 2 and 4 mg/l, the chlorophyll a content was higher (670 and 647 μg/l) than in the control (605 μg/l); at 7 and 10 mg/l, it significantly decreased to 87
and 65 μg/l, respectively. The contents of carotinoids in microalgal cells after 7 days of exposure to 2 and 4 mg/l were comparable
to the control values, while at 7 and 10 mg/l they decreased sharply. The amount of phaeophytin (as a percentage of total
chlorophyll a content) increased with increasing potassium bichromate concentration. 相似文献
9.
Determination of copper in human tissues and body fluids may be crucial in the diagnosis of Wilson’s disease. In this study
we evaluated urinary copper excretion and urine and blood concentration in 14 patients in whom Wilson’s disease was confirmed
(group A) and in 21 subjects in whom the disease was only suspected (group B). The following values (mean ± SD) were found:
24-h urine (μg Cu/24 h), 152 ± 135 (A) and 31.8 ± 10.9 (B); urine (μg Cu/ml), 0.091 ± 0.087 (A) and 0.028 ± 0.011 (B); and
blood (μg Cu/ml), 0.62 ± 0.25 (A) and 0.72 ± 0.09 (B). By comparison, urine copper concentration in the group of apparently
healthy subjects was 0.035 ± 0.010 (n = 50), and blood copper concentration in autopsy cases of nonpoisoned people was 0.85 ± 0.19 (n = 73). 相似文献
10.
Quantification of arbuscular mycorrhizal fungi activity by the glomalin concentration on hyphal traps 总被引:9,自引:0,他引:9
Strips of horticultural film (16–32 cm2) were used to trap extraradical hyphae emanating from roots of sudangrass [Sorghum sudanense (Piper) Staph] enclosed in 40-μm mesh bags and colonized by Gigaspora rosea FL 224-1, Glomus intraradices EY 113/114, or Glomus caledonium UK 301-1. Strips of film were placed at opposite sides of 17–21 replicate sand culture pots for each isolate and were removed
after 12–14 weeks of plant growth. To extract glomalin, a strip was cut into small pieces and submerged in 2 ml of 20 mM citrate,
pH 7.0 and then autoclaved for 60 min. A quantitative enzyme-linked immunosorbent assay (ELISA) detected 0.005–0.04 μg glomalin
in the volume of extract tested. The Bradford protein assay detected 1.25–5 μg of protein in the volume of extract tested.
Both assays gave results ranging from 5–40 μg glomalin/cm2 of film. Protein assay values were correlated with ELISA values (r=0.6091, P≤0.001, n=118). Analysis of variance indicated that isolates differed in Bradford protein values (P=0.001), but not ELISA values (P=0.154). Spatial variability of glomalin deposition ca. 7 cm from roots on opposite sides of pots was indicated by significant
paired T tests (P<0.05) for protein values for each of the three isolates and ELISA for two isolates. These results indicate that hyphal traps,
Bradford protein assay and ELISA are useful to assess hyphal activity over a growing season.
Accepted: 11 October 1998 相似文献
11.
K. Hofvendahl C. Åkerberg G. Zacchi B. Hahn-Hägerdal 《Applied microbiology and biotechnology》1999,52(2):163-169
Simultaneous saccharification of starch from whole-wheat flour and fermentation to lactic acid (SSF) was investigated. For
saccharification the commercial enzyme mixture SAN Super 240 L, having α-amylase, amyloglucosidase and protease activity,
was used, and Lactococcus lactis ssp. lactis ATCC 19435 was used for the fermentation. SSF was studied at flour concentrations corresponding to starch concentrations
of 90 g/l and 180 g/l and SAN Super concentrations between 3 μl/g and 8 μl/g starch. Kinetic models, developed for the saccharification
and fermentation, respectively, were used for simulation and data from SSF experiments were used for model verification. The
model simulated SSF when sufficient amounts of nutrients were available during fermentation. This was achieved with high wheat
flour concentrations or with addition of yeast extract or amino acids. Nutrient release was dependent on the level of enzyme
activity.
Received: 26 January 1999 / Accepted: 20 February 1999 相似文献
12.
Abakay A Gokalp O Abakay O Evliyaoglu O Sezgi C Palanci Y Ekici F Karakus A Tanrikulu AC Ayhan M 《Biological trace element research》2012,145(2):151-157
The aim of this study was to investigate the respiratory function disorders that could be related to dust exposure during
the production of copper mine in copper mineworkers (CMWs). The study included 75 male CMWs (mean age, 32.0 ± 7.1 years, 58.6%
smokers) and 75 male age- and smoking status-matched healthy control subjects. Serum Cu level was significantly higher in
the CMW group (0.80 ± 0.62 μg/ml) than the control group (0.60 ± 0.39 μg/ml) (p = 0.017). Significant negative correlations were found between serum Cu level and forced expiratory volume in first second
(r = −0.600; p < 0.001) and between serum Cu level and forced vital capacity (r = −0.593; p = <0.001) in CMWs. Serum Cu level was significantly higher in the restrictive type pulmonary function disorders group (1.36 ± 0.62 μg/ml)
than obstructive type (0.90 ± 0.55 μg/ml) and normal pulmonary function pattern group (0.53 ± 0.43 μg/ml) (p < 0.001). Patients with radiological parenchymal abnormalities had significantly higher serum copper levels than those without
abnormalities (1.53 ± 0.52 vs. 0.71 ± 0.52 μg/ml, respectively; p = 0.002). In conclusion, result of the study has shown a negative association between pulmonary functions disorders and radiological
abnormalities and serum Cu levels in CMWs. 相似文献
13.
Young-Jae Kim Oyunbileg Galindev Jun Han Sei Su-Mi Bae Hosub Im Lanying Wen Young Rok Seo Woong Shick Ahn 《Biological trace element research》2009,131(2):103-109
Of trace elements in the serum of living organisms, selenium (Se) is an essential mineral and plays the role of an antioxidant
as selenoproteins protecting the organism against oxidative damage induced by hydrogen peroxide, other lipid hydroperoxides,
and their derivatives. The aim of this study was to determine the mean serum Se levels in healthy Korean volunteers (50 males
and 50 females) by using an inductively coupled plasma-mass spectrometry method. The samples were collected at the Health
Promotion Centre of Kangnam St. Mary’s Hospital, College of Medicine, the Catholic University of Korea, Kangnam District,
Seoul in accordance with procedures approved by the Institutional Review Board of the Catholic University of Korea. The mean
serum Se level in healthy subjects was 112.05 ± 30.42 μg/l. For gender, it was 120.81 ± 27.37 μg/l for females and 103.29 ± 31.05 μg/l
for males. From the study result, there was a significant difference between the mean Se concentrations of gender groups (p = 0.0035). Also, the study indicated no effect of age on Se levels (p > 0.05) in the healthy individuals. 相似文献
14.
Teng X Shi X Shan Z Jin Y Guan H Li Y Yang F Wang W Tong Y Teng W 《Biological trace element research》2008,121(1):23-30
Iodine excess may lead to thyroid diseases. Our previous 5-year prospective survey showed that the prevalence and incidence
of hypothyroidism or autoimmune thyroiditis increased with iodine intake. The aim of the present study was to investigate
the optimal range of iodine intake by comparing the prevalence of thyroid diseases in three areas with slightly different
levels of iodine intake. In 2005, 778 unselected women subjects from three areas with different iodine intake levels were
enrolled. Levels of serum thyroid hormones, thyroid autoantibodies, and urinary iodine were measured, and thyroid B ultrasounds
were performed. Among the subjects with mildly deficient iodine intake, those with adequate intake, and those with more than
adequate intake, the prevalence of clinical and subclinical hypothyroidism was 0, 1.13, and 2.84%, respectively (P = 0.014); that of thyroid goiter was 24.88, 5.65, and 11.37%, respectively (P < 0.001); that of serum thyrotropin values was1.01, 1.25, and 1.39 mIU/l, respectively; and that of serum thyrotropin/thyroglobulin
ratio was 7.98, 6.84, and 5.11, respectively (P < 0.001). In conclusion, median urinary iodine 100~200 μg/l may reflect the safe range of iodine intake levels. Serum thyrotropin/thyroglobulin
ratio might be a better index of evaluating iodine status. 相似文献
15.
Shahzad Z. Iqbal R. Russell M. Paterson Ijaz A. Bhatti Muhammad R. Asi Munir A. Sheikh Haq N. Bhatti 《Mycotoxin Research》2010,26(3):205-209
The occurrence of aflatoxin B1 (AFB1) in chilies from Pakistan was determined by using HPLC in work undertaken in Pakistan.
Whole (n = 22) and powdered (n = 22) chilies were analyzed. Sixteen (73.0%) and 19 (86.4%) samples of whole and ground chilies, respectively, were contaminated.
The mean concentration in powdered chilies (32.20 μg/kg) was higher statistically than in whole chilies (24.69 μg/kg). Concentrations
ranged from 0.00 to 89.56 μg/kg for powdered chilies, compared with 0.00–96.3 μg/kg for whole chilies. The limits of detection
and quantification were 0.05 μg/kg and 0.53 μg/kg, respectively. The concentrations were high in general and greater than
the statutory limit set by the European Union. There is considerable scope for improvements in chili production in Pakistan. 相似文献
16.
Sherri M. Jones Timothy A. Jones Roshni Shukla 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1997,180(6):631-638
Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred
within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and
amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms−1 ranged from 1265 ± 208 μs (P1, N = 18) to 4802 ± 441 μs (N4, N = 13). Amplitudes ranged from 3.72 ± 1.51 μV (P1/N1, N = 18) to 1.49 ± 0.77 μV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from −38.7 ± 7.3 μs dB−1 (P1, N = 18) to −71.6 ± 21.9 μs dB−1 (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 ± 0.08 μV dB−1 (P1/N1, N = 18) to 0.07 ± 0.04 μV dB−1 (P3/N3, N = 11). The mean response threshold across all animals was −21.83 ± 3.34 dB re: 1.0 g ms−1 (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity.
Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and
specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide
a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail.
Accepted: 18 January 1997 相似文献
17.
dos Santos Rocha PB de Castro Amorim A de Sousa AF do Monte SJ da Mata Sousa LC do Nascimento Nogueira N Neto JM do Nascimento Marreiro D 《Biological trace element research》2011,143(2):603-611
Research has investigated the participation of zinc transport proteins and metallothionein in the metabolism of this mineral.
However, studies about the genetic expression of these proteins in obese patients are scarce. The study determined the expression
of zinc transporter protein codifying genes (ZnT-1, Zip-1 and Zip-3) and of metallothionein in 55 obese women, aged between
20 and 56 years. The assessment of body composition was carried out using anthropometric measurements and bioelectrical impedance.
Zinc intake was obtained by recording diet over a 3-day period, and the nutritional analysis was carried out using NutWin
software version 1.5. The plasmatic and erythrocytary zinc were analyzed by atomic absorption spectrophotometry (λ = 213. 9 nm). The determination of mRNA expression of the zinc transporter proteins and metallothionein was carried out using
blood, using the RT-PCR method. The mean values of body mass index were 37.9 ± 5.5 kg/m2. The average intake of zinc was 9.4 ± 2.3 mg/day. The analysis of the zinc plasma concentrations showed values of 58.4 ± 10.9 μg/dL.
The mean values of zinc in the erythroytes were 38.7 ± 9.1 μg/g Hb. The metallothionein gene had a higher expression in the
blood, when compared to zinc transporters ZnT-1, Zip-1, and Zip-3 (p = 0.01). The study shows that there are alterations in the biochemical parameters of zinc in obese patients assessed, as
well as higher expression of the codifying gene metallothionein, when compared to the investigated zinc transporters. 相似文献
18.
Cadmium and mercury concentrations were measured in the tissues of 64 individual albatrosses [23 wandering albatrosses (Diomedea exulans), 9 royal albatrosses (Diomedea epomophora) and 32 shy albatrosses (Thalassarche cauta)] which were killed as by-catch in longline fishing activities between 1991 and 1994. Mercury concentrations were also determined
for 33 shy albatross eggs (excluding shells). The birds were all sexed and assigned to one of two age classes (immature and
adult). The three species exhibited differences both in overall concentrations of cadmium and mercury, and also in the pattern
of accumulation of metals with age and sex. Wandering albatrosses exhibited the highest mercury concentrations with a mean
concentration in adult liver samples of 920.0 ± 794.1 μg g−1 dry weight. Shy albatrosses had the lowest mercury concentrations with mean concentrations in adult livers of 36.3 ± 21.4 mg
g−1 dry weight. The highest mercury concentration was 1800 μg g−1 for an adult female wandering albatross. Cadmium concentrations were less variable, with adult royal albatrosses having the
highest average concentrations (180.0 ± 165.0 in adult kidneys) and adult shy albatrosses the lowest (40.1 ± 20.0 in adult
kidney). The highest individual cadmium concentration was 287 μg g−1 for a juvenile wandering albatross. There was no evidence of increased accumulation of cadmium with age in any of the species,
but wandering albatrosses showed higher mercury concentrations in adults than juveniles. Female wandering albatrosses also
had significantly higher mercury concentrations than males. The mercury contents of the shy albatross eggs were very low,
with a maximum concentration of 5.4 μg g−1. The results of this study are consistent with the findings of previous work on albatrosses and support the notion that the
life-history strategy of these species (i.e. long-lived with low reproductive output) may be an important determinant in the
concentrations of some metals found in their tissues.
Accepted: 15 February 1999 相似文献
19.
The synthesis of poly(3-hydroxyalkanoates) (PHA) by Pseudomonas putida KT2442 growing on long-chain fatty acids was studied in continuous cultures. The effects of the growth rate on the biomass
and polymer concentration were determined and it was found that the PHA concentrations decreased with increasing growth rates.
The highest volumetric productivity was 0.13 g PHA l-1 h-1 at a specific growth rate (μ) of 0.1 h-1. The molecular mass of the polymer remained constant at all growth rates but changes in the monomeric composition of the
PHA synthesized were observed. Variation of the carbon to nitrogen (C/N) ratio of the substrate feed at μ=0.1 h-1 revealed optimal PHA formation at C/N=20 mol/mol. In order to optimize PHA production P. putida KT2442 was cultivated to high cell densities in oxygen-limited continuous cultures. In this way a maximum biomass concentration
of 30 g/l containing approximately 23% PHA was achieved. This corresponds to a volumetric productivity of 0.69 g l-1 h-1.
Received: 14 December 1995 / Received revision: 18 April 1996 / Accepted: 22 April 1996 相似文献
20.
Monica Daniela Doşa Laurentiu-Tony Hangan Eduard Crauciuc Cristina Galeş Mihai Nechifor 《Biological trace element research》2011,142(1):36-46
Research was performed on a group of 30 patients with non-insulin-dependent diabetes mellitus (NIDDM), who never received
antidiabetic medication before, and on a group of 17 healthy adults. The patients were administered treatment with metformin,
1,000 mg/day. Plasmatic and urinary concentration of magnesium have been measured, copper and zinc along with the concentrations
of glucose, HDL, LDL, cholesterol, tryglicerides, HbA1c, and total erythrocyte magnesium, in advance and after 3 months of
treatment. Data showed significant differences in the NIDDM group vs the control group: for plasma magnesium—1.95 ± 0.19 vs
2.20 ± 0.18 mg/dl, p < 0.001; urine magnesium—237.28 ± 34.51 vs 126.25 ± 38.22 mg/24 h, p < 0.001; erythrocyte magnesium—5.09 ± 0.63 vs 6.38 ± 0.75 mg/dl, p < 0.001; plasma zinc—67.56 ± 6.21 vs 98.41 ± 20.47 μg/dl, p < 0.001; urine zinc—1,347.54 ± 158.24 vs 851.65 ± 209.75 μg/24 h, p < 0.001; plasma copper—111.91 ± 20.98 vs 96.33 ± 8.56 μg/dl, p < 0.001; and urine copper—51.70 ± 23.79 vs 36.00 ± 11.70 μg/24 h, p < 0.05. Treatment with metformin for 3 months modified significant erythrocyte magnesium—5.75 ± 0.61 vs 5.09 ± 0.63 mg/dl,
p < 0.001 and urine magnesium—198.27 ± 27.07 vs 237.28 ± 34.51 mg/24 h, p < 0.001, whereas it did not modify significant the plasmatic and urinary concentration of the other cations. The erythrocyte
magnesium concentration was inversely correlated with HbA1c (r = −0.438, p = 0.015). The plasma level of copper was positively correlated with HbA1c (r = 0.517, p < 0.003), tryglicerides (r = 0.534, p < 0.003), and cholesterol (r = 0.440, p < 0.05), and the plasma level of zinc was inversely correlated with glycemia (r = −0.399, p = 0.029). Our data show a significant action of metformin therapy, by increasing the total intraerythrocyte magnesium concentration
and decreasing the urinary magnesium elimination, positively correlated with the decrease of glycemia and HbA1c in NIDDM patients. 相似文献