Zinc protection against cadmium effect on estrual cycle of wistar rat

A single dose of cadmium chloride (2.2 mg/kg of body wt) increased the estrual cycle period about two times. This effect could be prevented by means of simultaneous administration of zinc at the same dose.     

Copper deficiency and hyperlipoproteinemia induced by a tetramine cupruretic agent in rabbits

The effectiveness of a cupruretic agent, N,N'-bis-(2 amino ethyl)-1,3-propanediamine HCl or 2,3,2-tetramine HCl (TETA), in the induction of copper (Cu) deficiency and the ability of a Cu-deficient diet in the maintenance of the depressed Cu status 10 wk after TETA treatment were examined in this study. In the first experiment, 42 male New Zealand White rabbits, 35 d of age, were randomly divided into three dietary treatments: a copper (Cu)-deficient (2.3 mg Cu/kg diet), a Cu-adequate (13.5 mg Cu/kg diet), and a commercial ration (21.6 mg Cu/kg diet) group. A single oral dose of 100 mg of 2,3,2-tetramine HCl TETA/kg body wt/d were administered to half of the rabbits from each treatment group for 10 d while the remaining rabbits were untreated. In the second experiment, 10 similar rabbits were assigned to three treatments: Cu-deficient plus TETA (n = 4); Cu-adequate plus TETA (n = 3); and Cu-adequate alone (n = 3). The rabbits were fed a TETA dose of 100 mg/d for three 4-d periods over 3 wk, and thereafter maintained on the diets for another 10 wk. Rabbits from the first experiment fed Cu-deficient diet and treated with TETA demonstrated cardiac hypertrophy and markedly reduced plasma and liver Cu concentrations that indicated that the animals were Cu-deficient. Significant elevations (twofold) in low density lipoprotein (LDL) protein, cholesterol, triglyceride, and apolipoprotein B (apo B) concentrations were observed in TETA treated rabbits fed Cu-deficient diet. In the second experiment, the plasma LDL protein level remained elevated, the plasma Cu level was reduced 45%, and the Cu level of the heart when expressed as microgram/g dry tissue was reduced, 10 wk post TETA treatment in rabbits maintained on Cu-deficient diet. Thus, Cu deficiency and hyperlipoproteinemia was rapidly induced by TETA and was still evident 10 wk posttreatment in rabbits maintained on a Cu-deficient diet.     

Enhancement of the kidney Cd burden by SH-containing chelating agents

The accumulation of Cd in the kidneys is enhanced markedly if chelating agents that contain SH-groups like 2,3 dimercaptopropanol (BAL) are injected immediately after the metal. This is not a transient effect but persists for more than 3 d. It is less pronounced at higher chelate doses or when the pH of urine is increased. Our experiments indicate that chelating agents, which form unstable complexes at acid pH and are able to pass through the cell membrane, will cause metal accumulation in the kidneys.     

Cell orientation induced by extracellular signals

Cells like fibroblasts and osteoblasts are oriented by different extracellular guiding signals like an electric field, a bent surface, and a periodically stretched surface. An automatic controller is responsible for the cell alignment. The controller contains both a deterministic and a stochastic signal. The following machine properties were determined: (1) The angle dependence of the cellular signal transformer is cos 2(psi 0 - psi). (2) The set point of the automatic controller is psi 0 = +/- 90 degrees. The cells like to orient their long axis perpendicular to the direction of the applied guiding signal. (3) The signal transformer measures the extracellular signal in a quadratic fashion. The cells cannot register the sign of the guiding field. (4) The stochastic signal in the automatic controller can be quantified by a characteristic time (approximately 130 min for fibroblasts). (5) The extracellular signal is registered in cell-made standards (ratio of the deterministic and stochastic signal equals one): 0.3 +/- 0.05 V/mm for human fibroblasts (electric field) and 85 +/- 3 microns for human fibroblasts and osteoblasts (cyclindrically bent surface). (6) The lag-time in the signal transduction system of fibroblasts is approximately 4 min.     

Effects of doxorubicin on the sensitivity of L1210 leukemia cells to deformation-associated trauma

Most of the cancer cells arrested in the microcirculation during hematogenous metastasis are rapidly killed; one major mechanism is surface-membrane rupture, associated with the mechanical deformation of cancer cells in capillaries. The feasibility of increasing the susceptibility of cancer cells to lethal, deformation-associated trauma by doxorubicin, was tested in an in vitro mechanical model system, by filtering suspensions of L1210 leukemia cells through 8-μm pore-size Nuclepore® membranes, with or without prior incubation with 10^-7M doxorubicin. The results showed that mechanically-induced loss of cancer cells immediately after filtration was increased from 18 to 55% in cells previously exposed to doxorubicin for 48 h. The results indicate the feasibility of chemotherapeutic enhancement of the mechanical killing-action of the microvasculature as a potential rate-regulator of hematogenous metastasis.     

Characterization of a nickel resistant mouse cell line

Nickel is a potent carcinogen and, at high concentrations, is toxic to mammalian cells. The effects associated with nickel exposure are well-documented but its mechanism of action in the cell has not yet been fully described. In order to understand the metabolic fate of nickel in mammalian cells, a variant cell population has been selected that continues to grow and divide in the presence of nickel chloride concentrations that are toxic to the parental cell line (Balb/c-3T3 mouse fibroblasts). Nickel resistance is not caused by altered uptake of nickel from the medium or increased clearance from the cells and is not associated with changes in metallothionein expression. Compared to the normal cells, the nickel resistant cells have a decreased number of chromosomes and numerous centromeric fusions. The expression of some proteins and the distribution of nickel bound by various proteins are altered in the nickel resistant cells. Preliminary results indicate that the nickel resistant phenotype may be transferred by genomic DNA-mediated transfection into a recipient NIH-3T3 cell line. Current investigations are directed at identifying a gene responsible for nickel resistance.     

A new technique for the study of erythrocyte survival by double labeling and use of a well-type Ge detector

A double label procedure with⁵⁷Co and⁵⁸Co has been developed for detailed in vivo studies of erythrocyte survival. A well-type Ge detector is used in the measurements. The activities necessary for these experiments are very low, and the associated dose received by the test persons can be neglected.     

Effects of etretinate on the distribution of elements in rats

We studied in the rat the effects of the drug etretinate (Tigason), given at three doses 3, 10, and 30 mg/kg body wt for 1 mo, on the concentrations of Na, K, Ca, Mg, Fe, S, P, Cu, and Zn in the plasma, brain, thymus, heart, liver, lung, kidney, testicle, muscle, and bone. The elements were simultaneously determined in tissues after nitric acid dissolution by inductively coupled plasma emission spectrometry using a JY 48 instrument. At the dose of 3 mg/kg, etretinate did not induce any statistically significant modifications of the element distribution. At the dose of 10 mg/kg, the main observed modifications were in plasma an increase of copper (+38%) and a decrease of zinc (-25%). At the highest dose of 30 mg/kg, some variations of the concentrations of elements in tissues were observed. But, on no account did retinoids induce an alteration of the mineral composition of bone, despite obvious macroscopic bone alterations.     

The involvement of heterochromatic damage in nickel-induced transformation

Nickel ions produce selective damage in heterochromatic regions of chromosomes. Male Chinese hamster embryo cells, which have heterochromatin along the entire long arm of the X-chromosome, exhibit an unusually high incidence of nickel-induced transformation compared with female cells of the same species. However, 3-methylcholanthrene, a carcinogen that produces a random distribution of chromosome damage, transforms female and male cells equally. Other species that do not have as much heterochromatin on the X-chromosome exhibit similar incidences of nickel-induced tumors in males and females. Four out of five of the male nickel-transformed Chinese hamster cell lines exhibit a deletion of the heterochromatic long arm of the X-chromosome as the only common karyotypic aberration. This result indicates that a deletion of a heterochromatic chromosomal region may be an important feature of the nickel-induced carcinogenic process. All of the male nickel transformed cells lines are able to form tumors in athymic nude mice.     

Determination of selenium in duplicate diets of residents of Pinhel,Portugal, by neutron activation

A rapid cyclic instrumental neutron activation analysis (CINAA) method has been used to determine the selenium content of 27 duplicate diet samples from each of the 27 districts surrounding Pinhel, Portugal. The accuracy and precision of the CINAA method have been evaluated by analyzing certified reference materials and observed to be within ±5–10% for samples containing at least 40 ppb of selenium. The detection limit has been found to vary between 26–42 ppb selenium depending on the sample composition. The average daily dietary intake has been calculated as 37 μg of selenium per day.     

Multielement determination in rice,wheat, and barley by instrumental neutron activation analysis

INAA has been used for the determination of Na, Mg, Al, Cl, K, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Br, Rb, Sr, Mo, and W in grains of rice, wheat, and barley, which were collected from different plant fields in Iraq. Samples and standards were irradiated in the IRT-5000 reactor, at neutron fluxes of 2 × 10¹³ cm⁻²·s⁻¹ and 3.2 × 10¹¹ cm⁻²·s⁻¹. Interferences of photopeaks with each other were considered, and reaction interferences were calculated and determined experimentally. Accuracy of our method was assessed by the analysis of IAEA standards Wheat Flour and Bovine liver. A good agreement has been achieved between the present results and recommended values. The precision and detection limit were determined for all elements in all types of grain.     

Measurement of exchange of trace metals between the body and its surroundings with the use of trace methodology

Application of general tracer theory to the problem of estimating fluxes of tracee between the gastrointestinal tract and the body proper, from observations of the movement of tracer, shows that a number of assumptions must be fulfilled. Two specific sets of assumptions are discussed and, in both cases, measurement of tracer fluxes yields information on the integrated absorption of the tracee.     

Interference of Manganese on neuroendocrinal system in exposed workers

The neurotoxic effects of Manganese (Mn) are well known, and are usually caused by high occupational exposure over long periods of time. The effects caused by low doses of this metal have been poorly evaluated. For this reason, we decided to evaluate neuroendocrinal tests in a group of 14 male workers employed in a ferrousmanganese foundry (exposed to Mn air concentrations within the TLV-TWA) and in 14 male control subjects, by analyzing FSH, LH, prolactin, and cortisol. The urinary Mn, prolactin, and cortisol levels were significantly higher in the worker’s group. The preliminary results of this research seem to show that for exposure below the TLV, Mn can somehow interfere with the neuroendocrine system. In order to confirm the existence of these effects and to verify their possible correlation with the dopaminergic control system, further studies are necessary.     

Maternal hair zinc concentration in neural tube defects in Turkey

Hair zinc concentration was measured in samples taken from 57 mothers who delivered infants with neural tube defects (NTD) (mainly anencephaly). Control groups consisted of 30 healthy mothers with normal offspring and 37 nonpregnant women from middle-income backgrounds. Zinc concentration was also measured in the hair of eight infants with NTD (four being anencephalic). The mean maternal hair zinc concentration in the NTD group (128.2 +/- 38.9 micrograms/g) was lower than that of the control women (p less than 0.001), whereas the mean hair zinc level of malformed babies (250.4 +/- 85.2 micrograms/g) was significantly higher than that of normal infants (193.4 +/- 39.2 micrograms/g) (p less than 0.05). Maternal nutritional zinc deficiency was thought to be one of the factors responsible for NTD in Turkey.     

Clastogenic activity of strontium chloride on bone marrow cells in vivo

Oral administration of different concentrations of Strontium chloride to laboratory bred mice in vivo induced chromosomal aberrations in bone marrow cell metaphase preparations. The degree of clastogenicity was directly proportional to concentration used at 6, 12, and 24 h of treatment. Duration of treatment could only be related positively in the lower doses. The females showed greater susceptibility than the males at all concentrations used.     

New directions in liposome gene delivery

The history of liposomes, progress in liposome gene delivery, and future directions are discussed. Specific characteristics of liposomes and DNA:liposome complexes have been identified that are essential for optimal delivery and gene expression. Of particular interest are the requirements for increased delivery and high levels of gene expression in vivo. At present, significant efforts are focused towards achieving specific delivery and gene expression in target organs and tissues.     

Dietary calcium and blood lead levels in women

Nutritional factors are known to influence metabolism and toxicity of several metals in animal experiments, but relevant human data are scarce and inconclusive. In this work, we tested the hypothesis that dietary calcium influences lead metabolism in humans. Blood lead concentrations were used as indicators of lead exposure and metabolism. Two groups of peasant women living in similar conditions in two different regions in Yugoslavia (100 in each) were chosen as subjects for this purpose. In region A, the dietary calcium intake was about 940 mg, and in region B about two times lower, i.e., 450 mg/day. The average blood lead concentration was significantly lower in women from region A (69 micrograms/L) than from region B (83 micrograms/L). Our results support the assumption that adequate calcium intake might be one of the preventive measures for decreasing lead absorption. This new evidence, sought for some time by nutritionists and toxicologists, needs further international confirmation.     

Study of the oxidative metabolic function and chemotaxis of neutrophils from patients with cancer influenced by Selenium Yeast

The effects of Selenium Yeast (SY) given orally to patients with cancer on the oxidative metabolic function and chemotaxis of neutrophils were studied by Lumino-dependent Chemiluminescence (CL) assay and agarose plates assay, respectively. The results showed that the background CL and the peak value CL of neutrophils from patients with cancer 14 d after taking SY were, on the average, 4 and 1.2 times higher than those before taking SY. The chemotactic index (CI) and chemotactic differential (CD) increased in response to SY supplementation; the differences are statistically significant (p less than 0.01), and no corresponding differences could be seen in the control group (taking yeast).