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.     

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.     

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.     

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.     

Precise large deletions by the PCR-based overlap extension method

The authors describe an efficient method for generating large deletions (>200 nts) of precise length using the PCR-based method of gene splicing by overlap extension (1). This method is technically simple and less time consuming than conventional loop-out mutagenesis techniques requiring preparation of a single-stranded DNA template.     

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.     

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).     

Transformation of human kidney epithelial cells to tumorigenicity by nickel(II) and V-HA-RAS oncogene

Nickel is a toxic metal of environmental concern that has been found to be carcinogenic in man and animals. Primary human kidney (NHKE) cells were immortalized or rescued from senescence after exposure to NiSO₄. The cell lines (IHKE) displayed abnormal karyotype and anchorage independent growth was observed. However, none of the IHKE cells produced tumor upon injection into athymic nude mice. Transfer of the v-Ha-ras oncogene into IHKE cells induced conversion of the immortalized cells into cell lines (THKE) that were tumorigenic when transplanted into athymic nude mice. Ha-ras DNA was present in the transformed cell lines and expressed at high level.     

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.     

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.     

Hydroxyl radical and singlet oxygen production and DNA damage induced by carcinogenic metal compounds and hydrogen peroxide

Carcinogenic chromium(VI), iron(III) nitrilotriacetate, cobalt(II), and nickel(II) react with hydrogen peroxide leading to the production of active species including hydroxyl radical and singlet oxygen, which cause DNA damage.     

The distribution of cadmium within the human prostate

Five normal prostates from autopsies of humans aged 61-76 yr were divided into 2 x 24 topographically well-defined pairs of slices that were analyzed for cadmium (Cd) and examined histologically. The corresponding kidney cortex concentrations were also determined. The concentrations in ng Cd/g wet wt were in the range of 50-500 in the prostates and 8,000-39,000 in the kidneys with good mutual correlation. Large variations in Cd concentrations within the prostates were found. The concentrations were highest at the base (near the bladder) and lowest at the apex of the gland. Furthermore, large variations within horizontal layers were found, and this variation was not correlated to the histological amount of stroma or glands.     

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.     

Soluble vs insoluble hexavalent chromate

Soluble CaCrO₄ and insoluble PbCrO₄ were tested for induction of mutation to 6-thioguanine (base-substitution, deletion, addition, and frameshift mutations) or ouabain (base-substitution mutations) resistance in Chinese hamster ovary cells and morphological transformation in C3H/101/2 mouse embryo cells. CaCrO₄ induced dose-dependent cytotoxicity and mutation to 6-thioguanine resistance, but did not induce mutation to ouabain resistance or morphological transformation. Highly cytotoxic amounts of CaCrO₄ induced conversion of 10T1/2 cells to adipocytes, but cell lines derived from such cells were not transformed. PbCrO₄ was not mutagenic in either mutation assay but induced a dose-dependent, low frequency of focus formation. Cell lines established from these foci had a 3–5-fold increased saturation density, grew in soft agarose, and were tumorigenic in nude mice. Chronic exposure to CaCrO₄ or PbCl₂ did not induce transformation, PbCl₂ was inactive even at acutely cytotoxic concentrations, and sequential treatments with CaCrO₄ and PbCl₂ did not induce transformation. Light and scanning electron microscopy showed progressive cytoplasmic engulfment of PbCrO₄ particles and extensive vacuolization of cells in contact with the particles. No particles were observed inside of vacuoles. We suggest that internalization of PbCrO₄ and the associated cellular stress response may be related to PbCrO₄-induced neoplastic transformation of 10T1/2 cells.     

Production and purification of hybrid Ty-VLPs

This article describes how pure Ty-VLPs (virus-like particles) can be prepared from hybrid Ty-VLPs. Many different hybrid Ty-VLPs have been produced and may be easily purified. Since the sedimentation properties of different hybrid Ty-VLPs are similar, a simple purification process can be used for any VLP. This fast, versatile, and easy process allows for the production of a variety of recombinant proteins.