Study of trace elements in blood of cancer patients by proton-induced X-ray emission (PIXE) analysis

Proton-induced X-ray emission (PIXE) analysis was employed to determine the concentrations of six elements in the plasma and erythrocytes of 18 cancer subjects (15 males and 3 females) with neoplastic disorders and in 70 controls (35 males and 35 females). It was found that the concentrations of Br, K, and Zn were significantly elevated in the erythrocytes of the cancer subjects compared to the controls, whereas the concentration of Fe was significantly depressed, but with no difference observed in the concentration of Ca. In the plasma, the concentrations of Br, Cu, Ca, and K were significantly elevated, whereas the concentrations of Fe and Zn were found to be significantly depressed compared to the controls.     

A preliminary report on the intervention trials of primary liver cancer in high-risk populations with nutritional supplementation of selenium in China

The purpose of this study was to evaluate the effect of selenium (Se) in the prevention of human primary liver cancer. Three intervention trials were conducted among the residents at high risk to primary liver cancer (PLC) in Qidong county, Jiang-su province, the People's Republic of China. This area has the second highest rate of PLC in China. One trial was undertaken among the general population in a township with supplement of table salt fortified with 15 ppm anhydrous sodium selenite (Se-salt) for 5 y and the other four townships with similar PLC incidence rate served as the controls using normal table salt. The second trial was undertaken among hepatitis B virus surface antigen carriers (HBVsAg+) receiving supplement of 200 micrograms Se in form of selenized yeast (Se-yeast) daily vs placebo for 4 y. The third trial was carried out in members of families with high PLC incidence using Se-yeast (200 micrograms of Se daily) vs placebo for 2 y. The results showed that nutritional supplement of Se could reduce the PLC incidence significantly.     

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.     

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.     

Zinc transport by fibroblasts from patients with acrodermatitis enteropathica

Acrodermatitis enteropathica (AE) is a zinc deficiency disease. To date, the only defect has been demonstrated in the gut. We have investigated zinc uptake in fibroblasts established from four unrelated patients with AE using normal skin fibroblasts as controls. Zinc content of AE and control cells was similar (0.3 fmol/cell). Zinc accumulation over 24 h from a complete culture medium was similar in both normal controls and mutant cells. The fraction of zinc removed by Pronase treatment remained constant at 50 pmol/micrograms DNA, whereas the zinc remaining after Pronase treatment accumulated rapidly for 8 h, then more slowly. Analysis of binding data showed no significant difference between AE and control cells, with apparent Ka values of 4-6 X 10(6) M-1 and between 1 and 2 X 10(8) receptors/cell. Analysis of Pronase resistant data showed no difference between the control and the mutant cells with apparent Km values of 0.2-0.3 microM and Vmax values of 17-19 pmol/micrograms DNA/h. No difference in zinc efflux rates was detected. We conclude that the defect that underlies acrodermatitis enteropathica is either not expressed in fibroblasts or cannot be detected under these experimental conditions.     

Study of correlation of se content in human hair and internal organs by INAA

The correlations of essential element Se between human hair and kidney-cortex, liver, and lung from the same subjects were investigated by instrumental neutron activation analysis, using the reaction⁷⁶Se (n, γ)^77mSe, for 24 Chinese autopsies. The concentration of Se is higher in kidney-cortex (2.04–5.36 mg/kg) than in liver (0.73–2.29), lung (0.50–1.85), and hair (0.37–1.43). It is important to know that there are significant relationships of Se concentration between hair and the other three internal organs. The correlation coefficient by linear regression analysis are 0.639, 0.570, and 0.635 for liver, lung, and kidney-cortex, respectively; and theP values are all less than 0.01 for the three tissues.     

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.     

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.     

Attenuation of spontaneous pseudopod formation in human neutrophils by pentoxifylline

The effects of pentoxifylline (PTX) on spontaneous pseudopod formation in neutrophils in response to the tripeptide formyl-Met-Leu-Phe (fMLP), endotoxin, human complement C5a, and leukotriene B₄ (LTB₄) were examined in autologous plasma. Unseparated supernatant leukocyte suspensions from fresh heparinized venous human blood were incubated with PTX (0-5 mM) for 25 min and then stimulated for 5–25 min within a range of concentrations of fMLP, endotoxin, complement C5a, and LTB₄. The cell suspensions were fixed with glutaraldehyde and stained with crystal violet in acetic acid; the percentage of neutrophils with pseudopods was determined under high-resolution light microscope. The results show that PTX significantly decreases formation of pseudopods in the presence of all four stimulators. The mechanism of pseudopod suppression appears to be independent of the adenosine receptor. PTX and its analogues, HWA 138 and HWA 448, decreased pseudopod formation by similar amounts when stimulated with 10⁻⁸M fMLP. These results suggest that PTX may improve microvascular perfusion and attenuate neutrophilmediated injury by reducing the degree of neutrophil pseudopod formation in free suspension and microvascular entrapment.     

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.     

Sodium selenite therapy and thyroid-hormone status in cystic fibrosis and congenital hypothyroidism

The effectiveness of a peroral sodium selenite therapy (115 μg Se/m² BSA/d) administered to cystic fibrosis patients (n=32) could after three months be identified in a significant serum selenium increase (0.69→0.96 μmol/L), a significant malondialdehyde decrease (2.72→1.64 μmol/L), as well as in a significant serum vitamin E increase (4.31→5.72 μg/mL) Parallel to that, a serum T₃ increase as well as a highly significant decrease in the serum T₄/T₃-ratio were found, too, which point to improved peripheral T₄→T₃ conversion during selenium medication. Type-I-iodothyronine-5′-deiodinase has recently been identified as a specific selenoenzyme. In the case of congenital hypothyroidism (n=37) application of sodium selenite in the above specified dosage yielded a mean serum selenium increase (0.87→1.12 μmol/L), a not significant T₃ increase (2.57→2.61 nmol/L) as well as a not significant TSH decrease (5.34→4.49 mIU/L) without an expected T₄ decrease. With the serum lipids, however, a lowering of total cholesterol (4.85→4.53 mmol/L) simultaneous with a mean increase in HDL-cholesterol (1.52→1.66 mmol/L) as well as a decrease in LDL-cholesterol (2.93→2.52) could be observed. We view the reduction of the atherogenic serum lipid constellation in the course of selenium medication as an expression of increased thyroid-hormone efficacy.     

Expression vectors for the construction of hybrid Ty-VLPs

Purification of expressed proteins can be facilitated by expressing the rccombinant protein as a fusion with a carrier protein that assembles into paniculate structures. This article describes the use of expression vectors in producing a hybrid of the yeast retrotransposon Ty, which self-assembles into virus-like particles (VLPs). Hybrid VLPs can be used in such laboratory applications as the production of polyclonal and monoclonal antibodies, structure/function analyses, the detection of important antigenic determinants, and cpitope mapping of monoclonal antibodies.     

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.     

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.     

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.     

Human erythrocyte damage at the initial stages of oxidative stress

Specific fluorescent probes have been used to monitor changes in erythrocyte membranes in the first stages of the hemolytic process induced by irradiation with visible light in the presence of protoporphyrin IX. Although no change, or even a slight increase of fluorescence anisotropy, occurred with two probes having a preferential binding to membrane proteins, such as fluorescamine and 3-pyrene maleimide, the fluorescence anisotropy of two lipophilic probes, namely diphenyl-hexatriene and anilino-naphtalene sulfonate, underwent a substantial decrease upon irradiation.     

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.     

Deformation-Driven,lethal damage to cancer cells

Direct and indirect, in vivo and in vitro observations are in accord with the hypothesis that as a consequence of their deformation within capillaries, cancer cells undergo sphere-to-cylinder shape-transformations that create a demand for increased surface area. When this demand cannot be met by apparent increases in surface area accomplished by nonlethal, surface “unfolding,” the cell surface membrane is stretched; if expansion results in more than a 4% increase in true surface area, the membrane ruptures, resulting in cancer cell death. It is suggested that this deformation-driven process is an important factor in accounting for the rapid death of circulating cancer cells that have been trapped in the microvasculature. Therefore, this mechanism is thought to make a significant contribution to metastatic inefficiency by acting as a potent rate-regulator for hematogenous metastasis.     

Levels of some trace elements in selected autopsy organs,and in hair and blood samples from adult subjects of the Italian population

This study, which is part of a research program for the determination of trace element reference levels in various human tissues for the Italian population, presents the concentrations of Se, Hg, Cr, Cs, Sc, Rb, Zn, Fe, Co, and Sb in lung, liver, spleen, and kidney autopsy samples taken from 14 adult subjects of the Italian population who died from accidental causes. Concentrations of the same trace elements are given also for blood and hair samples taken from subjects of the general Italian population and of a population group living in a small coastal town that has an average annual fish consumption well above the national average. The analytical method used was Instrumental Neutron Activation Analysis. The levels and distribution of the trace elements in the various human organs examined are analyzed and discussed.