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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Starved cells of Candida utilis accumulated Zn2+ by two different processes. The first was a rapid, energy- and temperature-independent system that probably represented binding to the cell surface. The cells also possessed an energy-, pH-, and temperature-dependent system that was capable of accumulating much greater quantities of the cation than the binding process. The energy-dependent system was inhibited by KCN, Na2HAsO4, m-chlorophenyl carbonylcyanide hydrazone, N-ethylmaleimide, EDTA and diethylenetriaminepenta-acetic acid. The system was specific inasmuch as Ca2+, Cr3+, Mn2+, Co2+ or Cu2+ did not compete with, inhibit, or enhance the process, Zn2+ uptake was inhibited by Cd2+. The system exhibited saturation kinetics with a half-saturation value of 1.3 muM and a maximum rate of 0.21 (nmol Zn2+) min(-1) (mg dry wt(-1)) at 30 degrees C. Zn2+ uptake required intact membranes since only the binding process was observed in the presence of nystatin, toluene, or sodium dodecyl sulphate. Cells did not exchange recently accumulated toluene, or sodium dodecyl sulphate. Cells did not exchange recently accumulated 65Zn following the addition of a large excess of non-radioactive Zn2+. Similarly, cells pre-loaded with 65Zn did not lose the cation during starvation, and efflux did not occur when glucose and exogenous Zn2+ were supplied after the starvation period. Efflux was only observed after the addition of toluene or nystatin, or when cells were heated to 100 degrees C. Cells fed a large quantity of Zn2+ contained a protein fraction resembling animal cell metallothionein. In batch culture, cells of C. utilis accumulated Zn2+ only during the lag phase and the latter half of the exponential-growth phase.
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PMID:Accumulation and storage of Zn2+ by Candida utilis. 0 25

A reliable method for studying lead absorption and excretion in rats is described. Lead absorption occurs primarily in theduodenum where lead enters the epithelial mucosal cells. There is a relative mucosal block for lead with increasing intraluminal doses. Certain substances which bind lead and increase its solubility enhance its absorption. Iron, zinc, and calcium decrease the absorption of lead without affecting its solubility, probably by competing for shared absorptive receptors in the intestinal mucosa. The total body burden of lead does not affect lead absorption. Thus, lead does not have a feedback mechanism which limits absorption. Lead absorption is increased during rapid periods of growth and in iron-deficient animals. It is diminished with starvation and in iron-overloaded animals. The excretion and kinetics of tracer doses of radiolead were quantified. Erythrocytes seem to serve an important role in transport. Excretion occurs in urine and stool. Bile is an important route of excretion in the gut. Although most of a tracer dose is rapidly excreted, the excretory process is limited permitting lead accumulation primarily in bone.
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PMID:Factors affecting the absorption and excretion of lead in the rat. 63 10

The possible potentiation of an infection upon the metabolic consequences of trauma was tested in rats using a 2 X 2 block design which included control, femoral fracture, pneumococcal infection, and fracture plus infection groups. Infection introduced unique metabolic effects different from those of starvation, femoral fracture, or both together. Infection-induced effects included an accelerated conversion of 14C-alanine to glucose, higher serum haptoglobin, alpha2-macrofetoprotein, copper, and ceruloplasmin values, and lower serum iron, zinc, and transferrin concentrations. The first three of these infection-induced effects were diminished in rats with a femoral fracture. No measured effect of infection was increased in traumatized rats.
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PMID:Specific metabolic effects imposed by Streptococcus pneumoniae upon the response to femoral fracture in the rat. 90 63

The effect of zinc deficiency during the latter third of gestation on avoidance conditioning of young adult male rats was compared with the effect of intrauterine starvation and normal pregnancy. Animals which had experienced zinc deficiency avoided shock less well than the offspring of pair-fed control dams. The offspring of pair-fed dams avoided shock less well than animals which were the product of normal pregnancy. Response latencies were inferior in the zinc-deficient group, whereas intertrial responses were less on both the previous zinc-deficient and intrauterine starved animals.
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PMID:Some effects of prenatal zinc deficiency on behavior of the adult rat. 111 97

1. The main forage for camels in northern Djibouti (mangrove with Avicennia marina) is very poor in nitrogen and energy. In a trial, 32 young camels (less than 2 years old) were used in four groups of eight each. 2. All the camels received mangrove as basal diet ad lib. 3. After 1 month, the camels received mineral supplementation in copper and zinc (groups 1 and 3) or/and a concentrate rich in protein and energy (groups 2 and 3) or continued with the basal diet (controls). 4. Any supplementation was stopped after 2 months for 1 month. 5. Growth performance was 550 g/day (concentrate-supplemented camels) and 570 g/day (concentrate+mineral-supplemented camels). 6. The growth was negative for the two others groups (-260 g/day). 7. Food intake of mangrove was slightly more important with mineral supplementation only and with mineral+concentrate supplementation. 8. The changes in metabolic profiles have shown an important catabolism in non-supplemented animals, an increase of urea and free fatty acid concentrations in plasma and a decrease of glucose concentrations. 9. Three camels died in the control group with symptoms of starvation and signs of liver damage (increase of liver enzymes glutamate dehydrogenase and gamma-glutamyl transferase).
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PMID:The influence of high dietary protein, energy and mineral intake on deficient young camel (Camelus dromedarius)--I. Changes in metabolic profiles and growth performance. 135 89

O6-Methylguanine-DNA methyltransferase (MGMT) is decisively involved in protecting mammalian cells against genotoxic effects of alkylating carcinogens. We analysed regulation of MGMT expression after exposing rat hepatoma H4IIE cells to various 'stress' factors. Treatments that damage DNA such as alkylation, hydrogen peroxide, ultraviolet or X-ray exposure, as well as restriction enzymes introduced into cells by electroporation or arrest of replication by hydroxyurea significantly induced MGMT mRNA (2.5 to 5-fold). Slight induction (up to 2.5-fold) was observed after heat shock or cadmium/zinc treatment. No or only a very weak induction (less than 1.5-fold) was observed after treatment with 6-thioguanine, 5-azacytidine, transfection of methylated DNA, depletion of MGMT by feeding with O6-methylguanine or O6-benzylguanine, serum starvation and feeding of starved cells, cAMP, TPA and dexamethasone treatment. Inhibitors of protein kinases, H8 and H9, induced MGMT mRNA. On the other hand, an inhibitor of phosphatases (sodium vanadate) prevented induction of MGMT by N-methyl-N'-nitro-N-nitrosoguanidine. The data indicate that DNA breaks are an ultimate signal for MGMT mRNA induction and that protein phosphorylation is involved in regulating MGMT expression.
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PMID:Stress factors affecting expression of O6-methylguanine-DNA methyltransferase mRNA in rat hepatoma cells. 142 Mar 62

Zinc deficiency, whether a result of an acquired or inherited abnormality of zinc metabolism, is associated with characteristic cutaneous findings. The inherited variety is known as acrodermatitis enteropathica. We present a case of zinc deficiency secondary to starvation induced by anorexia nervosa. Since the cutaneous stigmata of zinc deficiency and anorexia nervosa can initially be subtle and occasionally overlap, we believe that screening zinc levels in patients with anorexia nervosa with prominent cutaneous findings should be considered.
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PMID:Acquired zinc deficiency in association with anorexia nervosa: case report and review of the literature. 148 78

The first scientific understandings on the value of nutrition and the assimilation of food, in the Greek language "metabole" (metabolism), are published in the Corpus Hippocraticum. But the conception of metabolism was introduced in scientific literature not earlier than 1839 by Theodor Schwann (1810-1882) and 1842 by Justus von Liebig (1803-1873). The antique ideas were completed in the 17th century by the theory of ferments, introduced by the iatro-chemist Johann Baptist van Helmont (1577-1644), and the Italian priest Lazzaro Spallanzani (1729-1799) could proof the existence of such processes in the living organism by animal experiments in 1776. Then Schwann could discover in the gastric juice a substance in 1835 which he called "pepsin". In the time of the voyages of discovery new, not yet known malnutritions on the ships were known as scurvy, beriberi and in the northern countries rickets. Then it became clear that not only the three groups of food, but also supplementary materials, known in 1912 as vitamines by Casimir Funk (1884-1967), could develop determined effects. The starvation in the first and the second world war showed clearly, that deterioration of food supply diminished the condition of immunity. Failed food experiments with gelatin, synthetically produced citric acid and the discussions of malnutrition diseases, based on a deficiency of zinc, of toddlers, are discussed as the malnutrition illness kwashiorkor in the third world. In conclusion a citation of the famous American physiologist Graham Lusk (1866-1932) is mentioned from the year 1906, who praised the scientific priority of the German medical research.
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PMID:[Nutrition and individual defense--historical considerations]. 205 90

The intracellular storage of zinc in Malpighian tubules of Drosophila hydei was studied by X-ray microanalysis of freeze-dried cryosections. Mass dense vacuoles in the proximal region of the anterior larval Malpighian tubule cells were found to accumulate zinc, not sodium. The zinc content was enhanced considerably after addition of zinc to the food of the larvae. Zinc-containing vacuoles were also found after pupation. After starvation of larvae in sea water, Na was detected in these vacuoles in addition to Zn. A small increase of Na and a remarkable increase of Zn was found in the vacuoles after injection of Ringer solution with ouabain into the larvae. Similar vacuoles in cells of untreated posterior tubules exhibit only low zinc levels.
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PMID:Mass dense vacuoles in Drosophila Malpighian tubules contain zinc, not sodium. A reinvestigation by X-ray microanalysis of cryosections. 208 40

Several species of protozoan parasites of the family Trypanosomatidae have a surface membrane-associated enzyme which is capable of hydrolyzing extracellular 3'-nucleotides and nucleic acids, thereby aiding in the acquisition of nutritionally required purines and Pi from their hosts. In Crithidia luciliae, this 3'-nucleotidase/nuclease previously has been shown to be highly regulated as purine and/or Pi starvation of this trypanosomatid leads to as much as a 1000-fold increase in enzyme activity. We have purified the enzyme to apparent homogeneity from detergent extracts of purine-starved C. luciliae by heparin-agarose chromatography followed by Mono Q and Mono S fast protein liquid chromatography. The enzyme had an apparent molecular weight of 43,000 and a pI of approximately 5.8. The enzyme displayed broad pH optima, with peaks at 8.0, for both nucleotidase and nuclease activities. The pH optima shifted to lower values when the activity was assayed in the presence of sulfhydryl reagents. The enzyme was most active with 3'-AMP and poly(A) in nucleotidase and nuclease assays, respectively. As a nuclease the enzyme hydrolyzed RNA at a faster rate than single-stranded DNA with no detectable hydrolysis of double-stranded DNA. The loss of enzyme activity which occurred upon storage at acid pH was prevented by the inclusion of Zn2+ in storage buffers. The physicochemical and kinetic properties of this trypanosomatid enzyme suggest that it is similar to the class I nucleases found in fungi and in germinating seedlings of higher plants.
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PMID:An inducible 3'-nucleotidase/nuclease from the trypanosomatid Crithidia luciliae. Purification and characterization. 215 95


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