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1.
Feeding a marginally low iron content diet (18-20 mg iron/kg diet) to weaned (21-day-old) rats for 8 weeks produced a significant decrease in liver non-heme iron (66%, p less than 0.001) but no change in blood hemoglobin. Total iron contents of liver (56%, p less than 0.01), spleen (20%, p less than 0.05), and kidney (19%, p less than 0.05) were also found to decrease along with increased zinc, copper, calcium, manganese lead and cadmium in various organs. The magnitude of alteration of a metal was different in different organs. However, liver was found to be the most affected organ. Two weeks of rehabilitation with iron-sufficient diet (390 mg iron/kg diet) normalized these altered levels.  相似文献   

2.
Summary Feeding a marginally low iron content diet (18–20 mg iron/kg diet) to weaned (21-day-old) rats for 8 weeks produced a significant decrease in liver non-heme iron (66%, p<0.001) but no change in blood hemoglobin. Total iron contents of liver (56%, p<0.01), spleen (20%, p<0.05), and kidney (19%, p<0.05) were also found to decrease along with increased zinc, copper, calcium, manganese lead and cadmium in various organs. The magnitude of alteration of a metal was different in different organs. However, liver was found to be the most affected organ. Two weeks of rehabilitation with iron-sufficient diet (390 mg iron/kg diet) normalized these altered levels.  相似文献   

3.
Summary In biotin-deficient rats, a decreased intestinal transport of Na+, H2O and L-phenylalanine, and no transport differences of 3-O-methyl-D-glucose were observed. The lower Na+ and L-phenylalanine transport appears to be referable to a decreased energy availability and probably not to the lack of a carrier.  相似文献   

4.
Summary Catalase, peroxidase and superoxide dismutase were found to inhibit significantly carrageenin edema and the primary phase of adjuvant arthritis in rats after i.v. injection. Heat-inactivated enzymes were as effective as the native enzymes. None of 10 scavengers of oxygen radicals inhibited the adjuvant arthritis at any time. Accordingly, no evidence for a participation of oxygen radicals in the secondary arthritis phase could be found, whereas a role of oxygen radicals in the primary arthritis phase and in carrageenin edema cannot be ruled out.  相似文献   

5.
Summary The effect of L-aspartic acid, L-asparagine and/or L-asparaginase were compared with those of imipramine on immobility, number of defecations, increase of nociceptive threshold, and hypothermia, induced by forced swimming in rats. L-Aspartic acid was found to be as effective as imipramine in reducing the effects of forced swimming, presumable by normalizing the decreased level of endogenous L-aspartic acid, due to the inhibition of L-asparaginase activity and/or by stimulated the inhibited enzyme. The other treatments antagonized the immobility, but not the increased number of defecations. All compounds abolished the elevation of nociceptive threshold and hypothermia.  相似文献   

6.
Zusammenfassung Die Synthese von Arginin-Vasopressin, Lysin-Vasopressin und Oxytocin, deren Glycinrest eine14C-Markierung trägt, wird mit Hilfe der Festkörpermethode nachMerrifield beschrieben.

Supported by National Institutes of Health grants No. AM-13567 and No. AM-10080 and the Atomic Energy Commission.

Abbreviations follow the rules of the IUPAC-IUB Commission on Biochemical Nomenclature in Biochemistry5, 2485 (1966). All optically-active amino acids are ofl-configuration. The following additional abbreviations were used: N-hydroxysuccinimide ester (OSu), ethanol (EtOH), methanol (MeOH), acetic acid (AcOH),n-butanol (n-BuOH), pyridine (Pyr) and N,N-dicyclohexylcarbodiimide (DCCI). Protected peptides and hormones were visualized on thinlayer plates according to the procedure byH. Zahn andE. Rexroth, Z. analyt. Chem.148, 181 (1955). The biological activities of the hormones were measured against the U.S.P. Posterior Pituitary Reference Standard; the four-point design was used for these bioassays and standard errors were calculated according to the method ofC. I. Bliss,The Statistics of Bioassay (Academic Press, New York, N.Y. 1952).

Acknowledgments. The authors wish to thank Mr.D. Schlesinger for some of the amino acid derivatives used, and MissM. Wahrenburg and Mrs.A. Silverman for bioassays.  相似文献   

7.
The distribution of eight components of the extracellular matrix in immature human placenta was studied by an indirect immunofluorescence method with monospecific antibodies. In the stroma of the term chorionic villi, collagen types I, III, IV, V, and fibronectin formed a mesh of fibers and conglomerates. Heparan sulphate proteoglycan formed multiple conglomerates, whereas laminin comprised small, scanty, discrete granules. Collagen type IV, laminin, entactin, and heparan sulphate proteoglycan were confined to the basement membrane of the trophoblast. Sometimes, only collagen type IV was identified in fetal vascular basement membrane.  相似文献   

8.
The goal of this study was to provide data on the dose-dependent production of dicentrics and micronuclei in human lymphocytes irradiated with 22.6 MeV protons and to estimate the possible contribution of intracellular superoxide dismutases (SOD) to the relative biological effectiveness (RBE) of protons. For the dose-response study, heparinized whole blood of a healthy volunteer was irradiated with protons and X-rays employing radiation doses of 0.5-4 Gy. Three biological endpoints were analyzed: chromosomal aberrations, micronuclei, and specific activity of cytosolic (CuZnSOD) and mitochondrial (MnSOD) superoxide dismutases in harvested human blood cells. Dicentric dose-response curves fit a linear-quadratic form (alpha = 0.094 +/- 0.006, beta = 0.032 +/- 0.001) induced with X-rays and (alpha = 0.119 +/- 0.057, beta = 0.029 +/- 0.014) for 22.6 MeV protons. Protons were more effective than X-rays in producing exchanges, particularly at 0.5 and 1 Gy. In contrast to X-ray irradiated samples where a significant increase in the specific activity of MnSOD was recorded (up to a radiation dose of 1 Gy), irradiation with protons markedly reduced its activity. As a consequence of the reduced activity of MnSOD, the chromosomal dose-response curve became quadratic. The RBE for dicentrics varies with dose (from 2.2 to 1.01) and reduced activity of MnSOD is an important contributor to the RBE of protons. SODs, particularly MnSOD, play an important role in defending DNA from reactive oxygen species. A reduced activity of SOD, particularly MnSOD, is an important contributor to the RBE of protons.  相似文献   

9.
The present article seeks to provide an overview of the general characteristics of the cultural and scientific climate in the Duchy of Urbino. Three of the Duchy’s milieus seem to have been particularly important for scholars who were engaged in the study of mathematics: the so-called “School of Urbino”, the environment of the court, and the world of the technicians and engineers. While the Urbino School has already been the object of previous studies, the other two milieus and their effect on the mathematicians’ work have been rather neglected and are, consequently, addressed here. The paper’s final section presents some documents that attest the importance of Renaissance scholars’ interaction with these environments to their actual scientific activity, taking the case of Guidobaldo dal Monte as an example.  相似文献   

10.
V Lance  D W Owens  I P Callard 《Experientia》1979,35(8):1119-1120
Plasma progesterone, testosterone, total estrogens and immunoreactive gonadotropin were measured in nesting and non-nesting sea turtles, Chelonia mydas. Progesterone and gonadotropin concentrations were significantly higher in nesting than in non-nesting turtles, testosterone was not significantly different in either group and total estrogens appeared to be slightly in the nesting group.  相似文献   

11.
This article discusses the intersection of science and culture in the marketplace and explores the ways in which radium quack and medicinal products were packaged and labelled in the early twentieth century US. Although there is an interesting growing body of literature by art historians on package design, historians of science and medicine have paid little to no attention to the ways scientific and medical objects that were turned into commodities were packaged and commercialized. Thinking about packages not as mere containers but as multifunctional tools adds to historical accounts of science as a sociocultural enterprise and reminds us that science has always been part of consumer culture. This paper suggests that far from being receptacles that preserve their content and facilitate their transportation, bottles and boxes that contained radium products functioned as commercial and epistemic devices. It was the 1906 Pure Food and Drug Act that enforced such functions. Packages worked as commercial devices in the sense that they were used to boost sales. In addition, 'epistemic' points to the fact that the package is an artefact that ascribes meaning to and shapes its content while at the same time working as a device for distinguishing between patent and orthodox medicines.  相似文献   

12.
Summary In hand-raised groups of 4 populations of Blackcaps, different patterns of juvenile moult as well as differences in wing length and body weight, adaptive to the various degrees of migratory performance, could be demonstrated. 33 F1-hybrids which were produced experimentally with 2 of these groups (1 African×1 European) showed an intermediate expression of these adaptations relevant to migration, indicating that these physiological and morphological features are under strong direct genetic control.  相似文献   

13.
When free DHEA, its sulfatide, and sulfate were assayed in maternal plasma as well as in umbilical cord arterial and venous plasma, rather high concentrations were found in either fraction from cord arterial plasma, reflecting the fetal contribution not only of free DHEA and DHEA sulfate, but also of the lipophile steroid sulfatide. Since high DHEA levels were associated with elevated c-AMP concentrations, a certain interrelationship of both parameters is indicated. In the course of delivery, a rapid decrease of free estriol in maternal plasma was observed. Higher concentration of free estriol in umbilical venous plasma pointed at its placental biosynthesis from fetal precursors.  相似文献   

14.
This article discusses the intersection of science and culture in the marketplace and explores the ways in which radium quack and medicinal products were packaged and labelled in the early twentieth century US. Although there is an interesting growing body of literature by art historians on package design, historians of science and medicine have paid little to no attention to the ways scientific and medical objects that were turned into commodities were packaged and commercialized. Thinking about packages not as mere containers but as multifunctional tools adds to historical accounts of science as a sociocultural enterprise and reminds us that science has always been part of consumer culture. This paper suggests that far from being receptacles that preserve their content and facilitate their transportation, bottles and boxes that contained radium products functioned as commercial and epistemic devices. It was the 1906 Pure Food and Drug Act that enforced such functions. Packages worked as commercial devices in the sense that they were used to boost sales. In addition, ‘epistemic’ points to the fact that the package is an artefact that ascribes meaning to and shapes its content while at the same time working as a device for distinguishing between patent and orthodox medicines.  相似文献   

15.
Summary The activity patterns of interneurones in the flight systems of dragonflies and mayflies were investigated using standard intracellular recording and staining techniques, and were compared with those of crickets and locusts. The results show several basic similarities in the operation of a central motor pattern generator for flight in all four groups of insects. These similarities can be explained as resulting from conservative evolution of flight pattern generating circuitry within the central nervous system.  相似文献   

16.
M Jemmali  Y Ueno  K Ishii  C Frayssinet  M Etienne 《Experientia》1978,34(10):1333-1334
Samples of corn suspected of causing infertility and refusal symptoms were analyzed and found to contain nivalenol, deoxynivalenol, T2 toxin and zearalenone, metabolites from Fusarium species.  相似文献   

17.
Summary Significant quantities of a newly discovered peptide, neuropeptide Y, were found in the rat pancreas, where they were localized to nerves in the exocrine parenchyma and around arterial and ductal structures. Although unaffected by surgical parasympathectomy, the periarterial and periductal nerves were abolished by chemical sympathectomy, suggesting that NPY is partially costored with sympathetic transmitters in nerve fibers.  相似文献   

18.
Summary Plasma progesterone, testosterone, total estrogens and immunoreactive gonadotropin were measured in nesting and non-nesting sea turtles,Chelonia mydas. Progesterone and gonadotropin concentrations were significantly higher in nesting than in non-nesting turtles, testosterone was not significantly different in either group and total estrogens appeared to be slightly higher in the nesting group.  相似文献   

19.
Phylogeography of crossbills, bullfinches, grosbeaks, and rosefinches   总被引:1,自引:0,他引:1  
Mitochondrial cytochrome b (cyt b) from 24 Carduelini species including crossbills, bullfinches, grosbeaks, rosefinches, and other related, but not conclusively classified species, was sequenced. These sequences were also compared with all the available sequences from the genera Carduelis, Serinus, and Passer. Phylogenetic analyses consistently gave the same groups of finches and the calculated divergence times suggest that speciation of the studied species occurred between 14 and 3 million years ago (Miocene-Pliocene), appearing before the Passer, Carduelis, and Serinus genera. Pleistocene glaciations may have been important in sub-speciation. Crossbills are integrated within the genus Carduelis, and within redpolls; the common crossbill shows subspeciation with Loxia japonica in the Pleistocene epoch. Pinicola enucleator groups together with bullfinches and is probably the ancestor of the group. Hawfinch is only distantly related to the studied groups, and might either represent an isolated genus or be related to the New World genus Hesperiphona. The grosbeak genera Eophona and Mycerobas are clearly sister groups, and species belonging to the former might have given rise to Mycerobas species. The isolated (in classification) Uragus sibiricus and Haematospiza sipahi are included within the genus Carpodacus (rosefinches); Carpodacus nipalensis is outside the genus Carpodacus in the molecular analyses and might be an isolated species or related to the genus Montifringilla.  相似文献   

20.
Summary Samples of corn suspected of causing infertility and refusal symptoms were analyzed and found to contain nivalenol, deoxynivalenol, T2 toxin and zearalenone, metabolites fromFusarium species.  相似文献   

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