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1.
M. A. Chaudhri M. Koulmanda M. T. Haukka N. Noorbakhs 《Biological trace element research》1987,12(1):149
There are some papers in the literature on the trace element contents of fetal livers of 20-wk gestation time and over. However,
there is very little information on this subject for fetal livers of less than 20-wk gestation. We have initiated a program
on the measurement of trace elements in fetal livers of 12–22-wk gestation, using thick-target X-ray fluorescence analysis.
The liver samples were obtained from freshly aborted fetuses. After removing blood from the samples, they were chopped into
small pieces and freeze dried. The resulting material was ground into fine powder and compressed into 3-mm thick pellets,
with boric acid backing. A similar pellet was also made of NBS—Bovine Liver—which was used as the standard for calculating
the absolute concentrations of different trace elements.
The measurements were carried out using a commercial Wave-Length-Dispersive XRF-System. Different X-ray tubes were used for
different sets of elements in order to maximize the detection sensitivity. The results are compared with those of fetal liver
of longer gestation and adult livers. 相似文献
2.
Jones JA Gray MR Oliveira BE Koch M Castellot JJ 《Journal of cell communication and signaling》2007,1(2):127-143
The six proteins of the CCN family have important roles in development, angiogenesis, cell motility, proliferation, and other
fundamental cell processes. To date, CCN5 distribution in developing rodents and humans has not been mapped comprehensively.
CCN5 strongly inhibits adult smooth muscle cell proliferation and motility. Its anti-proliferative action predicts that CCN5
would not be present in developing tissues until the proliferation phase of tissue morphogenesis is complete. However, estrogen
induces CCN5 expression in epithelial and smooth muscle cells, suggesting that CCN5 might be widely expressed in embryonic
tissues exposed to high levels of estrogen. 9–16 day murine embryos and fetuses and 3–7 month human fetal tissues were analyzed
by immunohistochemistry. CCN5 was detected in nearly all developing tissues. CCN5 protein expression was initially present
in most tissues, and at later times in development tissue-specific expression differences were observed. CCN5 expression was
particularly strong in vascular tissues, cardiac muscle, bronchioles, myotendinous junctions, and intestinal smooth muscle
and epithelium. CCN5 expression was initially absent in bone cartilaginous forms but was increasingly expressed during bone
endochondral ossification. Widespread CCN5 mRNA expression was detected in GD14.5 mice. Although CCN2 and CCN5 protein expression
patterns in some adult pathologic conditions are inversely expressed, this expression pattern was not found in developing
mouse and human tissues. The widespread expression pattern of CCN5 in most embryonic and fetal tissues suggests a diverse
range of functions for CCN5.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
Marta López Alonso Felipe Prieto Montaña Marta Miranda Cristina Castillo Joaquín Hernández José Luis Benedito 《Biometals》2004,17(4):389-397
Since the toxicity of one metal or metalloid can be dramatically modulated by the interaction with other toxic or essential metals, studies addressing the chemical interactions between trace elements are increasingly important. In this study correlations between the main toxic (As, Cd, Hg and Pb) and nutritional essential (Ca, Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Zn) elements were evaluated in the tissues (liver, kidney and muscle) of 120 cattle from NW Spain, using Spearman rank correlation analysis based on analytical data obtained by ICP-AES. Although accumulation of toxic elements in cattle in this study is very low and trace essential metals are generally within the adequate ranges, there were significant associations between toxic and essential metals. Cd was positively correlated with most of the essential metals in the kidney, and with Ca, Co and Zn in the liver. Pb was significantly correlated with Co and Cu in the liver. A large number of significant associations between essential metals were found in the different tissues, these correlations being very strong between Ca, Cu, Fe, Mn, Mo and Zn in the kidney. Co was moderately correlated with most of the essential metals in the liver. In general, interactions between trace elements in this study were similar to those found in polluted areas or in experimental studies in animals receiving diets containing high levels of toxic metals or inadequate levels of nutritional essential elements. These interactions probably indicate that mineral balance in the body is regulated by important homeostatic mechanisms in which toxic elements compete with the essential metals, even at low levels of metal exposure. The knowledge of these correlations may be essential to understand the kinetic interactions of metals and their implications in the trace metal metabolism. 相似文献
4.
Kjell Youngren Elisabeth Jeanclos Hana Aviv Masayuki Kimura Jeffrey Stock Moneer Hanna J. Skurnick Arlene Bardeguez A. Aviv 《Human genetics》1998,102(6):640-643
Telomere length, measured by terminal restriction fragments, was examined in tissues from human fetuses of gestational ages
estimated as 15–19 weeks. The length of telomeres was similar in most fetal tissues. However, there were significant variations
in telomere length among fetuses, with no apparent relationship between gestational age and telomere length. We conclude that
synchrony in telomere length exists among tissues of the human fetus. This synchrony is apparently lost during extrauterine
life.
Received: 12 January 1998 / Accepted: 19 March 1998 相似文献
5.
In September 2014, a pod of seven sperm whales (Physeter macrocephalus) was stranded along the Adriatic coast of Southern Italy. Concentrations of 20 essential and non-essential trace elements were quantified in the brain, muscle, liver and kidneys of three female sperm whales, which died in this event.The essential elements copper, iron, manganese and zinc showed low ranges of variability, suggesting a homeostatic physiological control, while selenium concentrations were associated with age. Molybdenum, nickel and chromium showed low ranges of concentrations and no evidence of preferential accumulation in selected organs. Very low concentrations of the non-essential elements cadmium, lead, tin and vanadium were detected in all tissues, suggesting a minor impact of these pollutants on the sperm whale populations of the Mediterranean Sea. Aluminum was revealed to have relatively high concentrations, together with a high variability between tissues and individuals, reaching the highest values in the kidneys and muscle of the oldest female, which was pregnant; the rare earth elements – lanthanum and cerium – were also detected in the kidneys of this female, indicating that pregnancy probably influenced metal concentrations in body tissues. 相似文献
6.
Sheep fetuses at day 70 of gestation (term = 145 days) were implanted subcutaneously with a biodegradable implant containing a luteinizing-hormone-releasing hormone (LHRH) agonist (buserelin) to investigate whether treatment with LHRH agonist would induce a state of desensitization of the fetal gonadotrophs and thus influence fetal gonadal development. Treatment with the LHRH agonist for 35-40 days caused a significant reduction in mean fetal plasma concentrations of LH and follicle-stimulating hormone (FSH) compared with control fetuses. LH pulses were evident in control fetuses but were completely abolished by buserelin treatment. Furthermore, the pituitary content of LH and FSH was significantly depleted in fetuses implanted with LHRH agonist. A bolus intravenous injection of 500 ng LHRH given to control fetuses caused a rapid and significant increase in plasma LH and FSH concentrations which was sustained for at least 60 min after injection. Pretreatment with buserelin completely abolished the LH and FSH responses to a bolus injection of LHRH. There were no differences between the sexes in fetal gonadotrophin concentrations or pituitary sensitivity to LHRH in control or agonist-treated fetuses. Furthermore, buserelin treatment for 35-40 days had no effect on the morphological appearance of the fetal gonads when compared with control fetuses, at least to day 110 of pregnancy. These results provide evidence for the induction of a state of desensitization of the LHRH receptors of the fetal pituitary gonadotrophs following long-term treatment with an LHRH agonist, but provide no evidence for a role for gonadotrophin secretion in gonadal development at this stage in fetal life. 相似文献
7.
M. A. Chaudhri M. Koulmanda M. T. Haukka N. Noorbakhs 《Biological trace element research》1987,12(1):149-149
There are some papers in the literature on the trace element contents of fetal livers of 20-wk gestation time and over. However, there is very little information on this subject for fetal livers of less than 20-wk gestation. We have initiated a program on the measurement of trace elements in fetal livers of 12–22-wk gestation, using thick-target X-ray fluorescence analysis. The liver samples were obtained from freshly aborted fetuses. After removing blood from the samples, they were chopped into small pieces and freeze dried. The resulting material was ground into fine powder and compressed into 3-mm thick pellets, with boric acid backing. A similar pellet was also made of NBS—Bovine Liver—which was used as the standard for calculating the absolute concentrations of different trace elements. The measurements were carried out using a commercial Wave-Length-Dispersive XRF-System. Different X-ray tubes were used for different sets of elements in order to maximize the detection sensitivity. The results are compared with those of fetal liver of longer gestation and adult livers. 相似文献
8.
Microenvironmental studies of pre-B and B cell development in human and mouse fetuses 总被引:5,自引:0,他引:5
Immunofluorescence techniques were used to trace the development of cells expressing mu heavy chains in humans and mice. IgM B cells were distinguished from pre-B cells by their additional expression of kappa or lambda light chains. Generation of pre-B and progeny B cells was evident in hemopoietic fetal liver and bone marrow, but not in thymus, heart, lung, spleen, kidney, and placental tissues. Pre-B and B cells, in a ratio of 2 to 1, were abundant in sections of hemopoietic liver and in bone marrow from 12- to 15-wk-old human fetuses, whereas these cells were rare in nonhemopoietic liver samples obtained beyond the 34th week. In mouse fetal liver mu+ cells appeared first around the 12th day of gestation and increased in frequency throughout the third trimester. On day 17 of gestation, kappa light chain expression by 1% of mu+ cells was noted, and the percentage of kappa+/mu+ cells increased progressively to more than 80% by 5 days after birth. Pre-B and B cells were interspersed among myeloid and more abundant erythropoietic cellular elements in the extrasinusoidal areas adjacent to hepatic cords. A loose clustering or "starburst" distribution pattern of pre-B cells became evident around day 17. These observations suggest a model for in situ generation of pre-B and progeny B cells in the hemopoietic fetal liver. In the midst of more numerous erythropoietic elements, immunoglobulin-negative precursors divide to generate a loose colony of mu+ pre-B cells that divide again before giving rise to a wave of IgM B cells. 相似文献
9.
Fowden AL Forhead AJ 《American journal of physiology. Endocrinology and metabolism》2011,300(1):E94-102
In adults, the adrenal glands are essential for the metabolic response to stress, but little is known about their role in fetal metabolism. This study examined the effects of adrenalectomizing fetal sheep on glucose and oxygen metabolism in utero in fed conditions and after maternal fasting for 48 h near term. Fetal adrenalectomy (AX) had little effect on the rates of glucose and oxygen metabolism by the fetus or uteroplacental tissues in fed conditions. Endogenous glucose production was negligible in both AX and intact, sham-operated fetuses in fed conditions. Maternal fasting reduced fetal glucose levels and umbilical glucose uptake in both groups of fetuses to a similar extent but activated glucose production only in the intact fetuses. The lack of fasting-induced glucogenesis in AX fetuses was accompanied by falls in fetal glucose utilization and oxygen consumption not seen in intact controls. The circulating concentrations of cortisol and total catecholamines, and the hepatic glycogen content and activities of key gluconeogenic enzymes, were also less in AX than intact fetuses in fasted animals. Insulin concentrations were also lower in AX than intact fetuses in both nutritional states. Maternal glucose utilization and its distribution between the fetal, uteroplacental, and nonuterine maternal tissues were unaffected by fetal AX in both nutritional states. Ovine fetal adrenal glands, therefore, have little effect on basal rates of fetal glucose and oxygen metabolism but are essential for activating fetal glucogenesis in response to maternal fasting. They may also be involved in regulating insulin sensitivity in utero. 相似文献
10.
Zinc deficiency (ZD) is teratogenic in rats, and fetal skeletal defects are prominent. This study identifies fetal skeletal malformations that affect calcified and non-calcified bone tissue as a result of gestational zinc deficiency in rats, and it assesses the effect of maternal ZD in fetal bone calcification. Pregnant Sprague-Dawley rats (180-250 g) were fed 1) a control diet (76.4 micrograms Zn/g diet) ad libitum (group C), 2) a zinc-deficient diet (0 microgram/g) ad libitum (group ZD), or 3) the control diet pair-fed to the ZD rats (group PF). On day 21 of gestation, laparotomies were performed. Fetuses were weighed, examined for external malformations, and stained in toto with a double-staining technique for the study of skeletal malformations. Maternal and fetal tissues were used for Zn, Mg, Ca, and P determinations. Gross external malformations were present in 97% of the ZD fetuses. No external malformations were found in fetuses from groups C and PF. Ninety-one percent of cleared ZD fetuses had multiple skeletal malformations, whereas only 3% of the fetuses of group PF had skeletal defects; no skeletal malformations were found in fetuses from group C. Some of the skeletal malformations described in the ZD fetuses, mainly affecting non-calcified bone, were not mentioned in previous reports, thus stressing the importance of using double-staining techniques. Examination of stained fetuses and counting of ossification centers revealed important calcification defects in ZD fetuses. These effects were confirmed by lower Ca and P concentrations in fetal bone with alteration of the Ca:P ratio. 相似文献
11.
Microbial heavy-metal resistance 总被引:57,自引:0,他引:57
D. H. Nies 《Applied microbiology and biotechnology》1999,51(6):730-750
We are just beginning to understand the metabolism of heavy metals and to use their metabolic functions in biotechnology,
although heavy metals comprise the major part of the elements in the periodic table. Because they can form complex compounds,
some heavy metal ions are essential trace elements, but, essential or not, most heavy metals are toxic at higher concentrations.
This review describes the workings of known metal-resistance systems in microorganisms. After an account of the basic principles
of homoeostasis for all heavy-metal ions, the transport of the 17 most important (heavy metal) elements is compared.
Received: 25 November 1998 / Received revision: 18 February 1999 / Accepted: 20 February 1999 相似文献
12.
The 3rd coronary artery, whose anatomical significance is defined, is a normal variant of the conus branch of the right coronary artery. This study involved the stereoscopic comparative investigation of human fetal hearts from 13 to 40 weeks of age and human adult hearts from 18 to 88 a of age. The incidence of the 3rd coronary artery in human fetuses was 45 out of 218 or 20.6%. No clear sexual differences were observed. Anastomoses had already developed between the 3rd coronary and the branches of the left anterior descending artery during the fetal stage. The 3rd coronary artery orifices in human fetuses was located at 9 o'clock (+/- 0 degree) most frequent (48.9%), and at 8 o'clock (-30 degrees) most infrequent (22.2%). The incidence of the 3rd coronary artery in human adults was 36.8%. In the human adult's normal group, the orifice was located at 9 o'clock (+/- 0 degree) most frequent (59.0%), and at 8 o'clock (-30 degrees) most infrequent (14.8%), while on the other hand in the pathologic group, the orifice was located at 9 o'clock (+/- 0 degree) most frequent (54.9%) and at 10 o'clock (+30 degrees) most infrequent (11.5%). Further, multiple 3rd coronary artery orifices, which were not observed in human fetal hearts, were observed in the human adults' heart. Furthermore, the existence of multiple orifices and the fact that human adult hearts had a higher incidence than human fetal hearts suggests the possibility that the 3rd coronary artery develops after birth. 相似文献
13.
Seasonal changes of zinc, copper, and iron in gilthead sea bream (Sparus aurata) fed fortified diets
Emilio Carpeme Rossella Serra Maurizio Manera Gloria Isani 《Biological trace element research》1999,69(2):121-139
Four groups of gilthead sea bream (Sparus aurata) were fed diets with additional metal contents: a basal diet (diet A) contained Zn at 60.9 ± 1.9 mg/kg diet, Cu at 3.9 ±
0.9 mg/kg diet, and Fe at 138.3 ± 6.8 mg/kg diet; the other diets were supplemented with copper (20 mg/kg, diet B), iron (100
mg/kg, diet C), or zinc (300 mg/kg, diet D). Two consecutive year-classes (0+ and 1+ age fish) from the same parent stock were examined. Several fish tissues were analyzed for metal contents in five different
periods of each year in order to determine (1) the sensitivity of certain tissues as indicators of trace element metabolism
and (2) possible seasonal variations. Growth data were similar for gilthead sea bream fed the basal diet and the metal-fortified
diets. Mineral concentrations in tissues were found to be little affected by the dietary supplementation of trace elements,
suggesting an efficient homeostatic control of these three metal concentrations. Tissues involved in metal metabolism (e.g.,
liver, kidney, gills) presented greater variations between minimum and maximum values with respect to other tissues (e.g.,
brain, muscle, eye). Seasonal variations were observed during the 2 yr of this study and were especially evident for zinc
and copper concentrations in the liver. The overall pattern of metal variations showed a decreasing trend during the 2 yr.
Results from this study indicate that (1) trace element concentrations in fish tissues vary with age and life cycle and (2)
trace element requirements may vary in function of age and life cycle. 相似文献
14.
The influence of experimentally produced oligohydramnios on lung growth and pulmonary surfactant content in fetal rabbits. 总被引:2,自引:0,他引:2
M Higuchi T Kato H Yoshino K Matsuda K Gotoh H Hirano K Koyama M Maki 《Journal of developmental physiology》1991,16(4):223-227
To study the effect of oligohydramnios on lung growth and biochemical lung development in fetal rabbits, amniotic fluid was drained through a tube inserted into the maternal peritoneal cavity on the 23 day of gestation. Littermate fetuses without an amniotic shunt were used as controls. The fetuses were delivered abdominally on the 28 day of gestation. In a total of 8 pregnant does, 17 fetuses underwent amniotic shunting and 22 fetuses were used as controls. The amniotic shunt produced a significant reduction in the amniotic fluid volume. There were no differences in the wet weights of the fetal body, liver or brain between the two groups. However, the amniotic shunt significantly decreased the wet weight of the fetal lung, fetal lung wet weight/body weight ratio, and protein concentration per lung as compared to the control fetuses. In the fetal liver and brain tissues, no changes were found in the concentrations of total phospholipids, phosphatidylcholine (PC) or disaturated phosphatidylcholine (DSPC, the main component of lung surfactant) per g of wet tissue and per mg of protein. However, the lungs of the fetuses with amniotic shunts contained significantly more PC and DSPC, and the L/S ratio was higher than in the control fetuses. These results suggest that the oligohydramnios produced by an amniotic shunt causes pulmonary hypoplasia, but raises the pulmonary surfactant content of fetal rabbit lung. 相似文献
15.
Vital cell labeling techniques were used to trace the fate of the medial edge epithelial (MEE) cells during palatal fusion in vivo. Mouse palatal tissues were labeled in utero with DiI. The fetuses continued to develop in utero and tissues of the secondary palate were examined at several later stages of palatal ontogeny. The presence and distribution of DiI was correlated with the presence of cell phenotype-specific markers. During the initial stages of palatal fusion the DiI-labeled MEE were present in the midline position. These cells were attached to an intact laminin-containing basement membrane and contained keratin intermediate filaments. At later stages of palatogenesis the DiI-labeled MEE were not separated from the mesenchyme by an intact basement membrane and did not contain keratin. In late fetal development, DiI-labeled cells without an epithelial morphology were present in the mesenchyme. The transition of the DiI-labeled cells from an epithelial phenotype to a mesenchymal phenotype is consistent with a fate of epithelial-mesenchymal transformation rather than programmed cell death. 相似文献
16.
Reem Rahil-Khazen Bj?rn J Bolann Andreas Myking Rune J Ulvik 《Journal of trace elements in medicine and biology》2002,16(1):15-25
Autopsy tissue samples from the brain front lobe, cerebellum, heart, kidney (cortex and medulla), liver, pancreas, spleen and ovary were analysed for AL, B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr and Zn in 30 (17 women and 13 men) subjects ranging in age from 17 to 96 years at Haukeland University Hospital in Norway. The tissues were selected from macroscopically normal organs and samples were handled according to guidelines recommended to avoid contamination in the pre-analytical phase. Concentration of the trace elements were determined by the inductively coupled plasma atomic emission spectrometry technique (ICP-AES). In most tissues the concentrations of the essential trace elements followed the order Fe> Zn> Cu> Mn> Se> Cr> Co except in the ovary where Se was higher than Mn. The liver was the major site of deposition for Co, Cu and Mn as well as the spleen for Co, brain front lobe for Cu and pancreas for Mn. Ba, Sr and Ni built up in the ovary foLLowed by the kidney. Older subjects accumulated Ba and Sr in most tissues, whereas Al accumulated in the kidney cortex and Cd in the brain cerebellum. Generally males had higher concentrations of trace elements in the different tissue sampLes than females with the exception of Mn in the brain front lobe and heart and Sr in the liver. ICP-AES is a useful method to assess the concentration and the profiLe of trace elements in human autopsy tissues. 相似文献
17.
R T Stone D R Campion J Klindt R J Martin 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1985,180(1):191-195
Lines of swine previously selected for either high backfat (obese) or low backfat (lean) were investigated to determine the effect of maternal obesity and the relationship between serum parameters and body composition. Fetal weight, percentage body protein, fat, fat-free organic matter and ash, and serum concentrations of albumin, growth hormone, triiodothyronine, and cortisol were compared in fetuses from straight line and reciprocal crosses at 110 days of gestation. Fetuses from the obese line weighed less but had a greater percentage body protein, fat, and fat-free organic matter than did fetuses from the lean line. Serum concentrations of albumin and triiodothyronine were less whereas those of growth hormone were greater in fetuses from the lean line compared to fetuses from the obese line. Values for these parameters in fetuses from the reciprocal crosses were generally intermediate to those of fetuses from the lean and obese lines. Comparisons of fetuses from the reciprocal and line crosses by linear contrast showed that the observed differences were mainly due to the average genetic effect of individual fetal genotypes and not due to maternal effects. Correlations computed from the residual variance showed a positive relationship between percentage body protein, serum albumin, and triiodothyronine while percentage body fat was not correlated with any of the other traits. Serum growth hormone was negatively correlated with fetal weight. We conclude that there is no apparent maternal effect of obesity or relationship of fetal fat content with any of the other variables measured in these lines of swine at the stage of fetal development at which these determinations were made. 相似文献
18.
Veronique Dermauw Marta Lopéz Alonso Luc Duchateau Gijs Du Laing Tadele Tolosa Ellen Dierenfeld Marcus Clauss Geert Paul Jules Janssens 《PloS one》2014,9(1)
The amount of trace elements present in edible bovine tissues is of importance for both animal health and human nutrition. This study presents data on trace element concentrations in semitendinosus and cardiac muscles, livers and kidneys of 60 zebu (Bos indicus) bulls, sampled at Jimma, Ethiopia. From 28 of these bulls, blood samples were also obtained. Deficient levels of copper were found in plasma, livers, kidneys and semitendinosus muscles. Suboptimal selenium concentrations were found in plasma and semitendinosus muscles. Semitendinosus muscles contained high iron concentrations. Trace elements were mainly stored in the liver, except for iron and selenium. Cardiac muscles generally contained higher concentrations of trace elements than semitendinous muscles except for zinc. A strong association was found between liver and kidney concentrations of copper, iron, cobalt and molybdenum. Liver storage was well correlated with storage in semitendinosus muscle for selenium and with cardiac muscle for cobalt and selenium. Plasma concentrations of copper, selenium, cobalt were well related with their respective liver concentrations and for cobalt and selenium, also with cardiac muscle concentrations. The data suggest multiple trace element deficiencies in zebu cattle in South-West Ethiopia, with lowered tissue concentrations as a consequence. Based on the comparison of our data with other literature, trace element concentrations in selected edible tissues of Bos indicus seem quite similar to those in Bos taurus. However, tissue threshold values for deficiency in Bos taurus cattle need to be refined and their applicability for Bos indicus cattle needs to be evaluated. 相似文献
19.
Giulia Andreani Stefano Cottignoli Bruno Perfetti Gorkem Kismali Emilio Carpenè Gloria Isani 《Biological trace element research》2010,137(2):177-189
Trace metals such as Zn, Cu, and Fe are essential for life; differently, no biochemical function is known for Cd. Changes
in dietary metal concentrations can cause deficiency or toxicity. Studies on trace elements in cat are lacking. This paper
aimed to analyze Zn, Cu, Fe and Cd concentrations in liver and kidney of pathological domestic cat and to isolate metallothionein
(MT) in these tissues. It was not possible to explore a possible correlation between metal concentrations and pathologies
because the incidence for each of them was too low. Fe was the most abundant metal; in particular, the liver accumulates average
Fe concentrations one order of magnitude higher than Zn and Cu, ranging from 66.75 and 1,444.23 μg/g. Significantly, higher
levels of Fe were found in the liver of elder animals. Zn concentrations varied between 26.31 and 84.78 μg/g in the liver
whereas in the kidney, ranged between 7.69 and 71.15 μg/g. Cu concentrations were between 2.37 and 112.91 μg/g in liver and
between 2.12 and 9.85 μg/g in kidney. Cd was the least abundant metal with the exception of the kidney of the oldest cats
where it reached a maximum of 13.71 μg/g. Gel-filtration metal distribution profiles from cytosolic extracts revealed the
presence of Cd, Cu, Zn thioneins either in the liver or in the kidney. Because tissue samples were taken from pathological
cats from different breed and age, care must be taken to use these data as a baseline profile of trace elements in healthy
animals. Our results are indicative that for some specimens the feed levels of Fe and Cu could be higher than the optimal
dietary intake and in few cats, there was also an exposure to Cd that was counteracted by MT biosynthesis. 相似文献
20.
A circular recombinant plasmid composed of a 12.5 kb fragment of human DNA including the entire insulin gene and the 4.3 kb bacterial plasmid pBR322 was microinjected into fertilized C57BL/6 mouse eggs. 753 eggs were injected with 30000 gene copies in a volume of 1-2 pl; 379 eggs survived micromanipulation and were subsequently cultured to the blastocyst stage. From 282 embryos that were transferred into the uteri of pseudopregnant ICR/Swiss foster females, 60 fetuses and corresponding placentas could be recovered at day 16-19 of pregnancy. High molecular weight DNA was extracted from these tissues and was screened with radioactively labelled hybridization probes for the presence of the injected DNA sequences. By restriction endonuclease analysis in conjunction with Southern blot hybridization, we found that in two normally developed fetuses at day 18, the fetal and placental tissues contained the human insulin gene including the flanking regions and bacterial plasmid sequences. Our results indicate that the injected DNA integrated into the mouse genome within its pBR322 region and properly replicated with the host DNA during development. The intensities of the hybridization bands suggest that at least one copy of foreign plasmid DNA was present per cell in the two fetuses and their placentas. 相似文献