Indwelled femoral vein non-cuffed, double-lumen hemodialysis catheter complicated by pulmonary thromboembolism.

Non-cuffed, double-lumen hemodialysis (HD) catheters can be inserted at the bedside in the femoral, internal jugular or subclavian position. The femoral route is less risky, and the incidence of life-threatening complications is lower for femoral cannulation than for internal jugular and subclavian cannulations. However, here we describe a life-threatening complication of an extensive deep vein thrombosis and subsequent pulmonary thromboembolism following femoral cannulation of a double-lumen HD catheter. The possible mechanisms and treatment for this potentially fatal thromboembolic event are discussed in this report.

Polarization-Dependent Periodic Pulse Oscillation in a Diode-Laser-Pumped and Intracavity Frequency-Doubled Nd:YVO 4 Laser.

We demonstrate that two cross-polarized longitudinal modes can have 50% higher conversion efficiency than two parallel-polarized longitudinal modes in a diode-laser-pumped and intracavity frequency-doubled Nd:YVO(4) laser when operated under periodic pulse oscillation. Through simulations of the rate equations for primary frequency intensities and gains, we also verify that this effect can be attributed to gain competition and complementary conversion coefficient between second-harmonic and sum-frequency generations.

Effects of ethionine feeding on urinary and tissue ascorbic acid concentrations in rats.

The effect of feeding 0.25% ethionine for 3-10 weeks to male and female rats on urinary and tissue ascorbate contents were studied. The concentrations of ascorbic acid in the urine, blood, liver and adrenals were significantly reduced in the rats receiving ethionine as compared to those receiving stock diet. This decrease was not apparently due to feed intake, not reversed by supplementation of methionine, but can be partially restored by removing ethionine from stock diet. The response to trichloro-2-methyl-2-propanol stimulation of urinary ascorbic acid was considerably suppressed by ethionine administration. In vitro the enzymatic synthesis of the vitamin from glucuronolactone by liver homogenate of ethionine-fed rats was significantly decreased from that of stock diet-fed controls. These results indicate that ethionine reduces the capacity to synthesize ascorbate which, in turn, causes a decrease of ascorbic acid contents in the urine, blood, liver and adrenals.

Zinc deficiency and bone formation in guinea pig alveolar implants.

Bone formation under zinc deficiency conditions was investigated using alveolar implants in guinea pigs, from which bone formed solely during the period of zinc deficiency could be obtaned. Thirty-six guinea pigs (GP) weighing 175-195 g were randomly divided into three groups: group 1 received a -Zn diet, (1.0 +/- 0.2 ppm Zn); group 2 pair fed control, and group 3 ad libitum control. After 3 weeks of dietary treatment, the right incisor was extracted and a nylon mesh tube (1.0 cm long) was implanted into the incisor alveolar cavity. Two weeks after implantation, all GP were killed and bone-containing nylon implants (BCNIs) and femurs were removed for Zn, Ca and P analyses. Compared to the two control groups, -Zn group showed two to fourfold less zinc in femurs and in BCNIs, respectively. Femur, but not BCNI, from pair-fed GP had significantly higher zinc concentration than that of GP in group 3, Ca and P concentrations in -Zn BCNI were not significantly reduced, but P in -Zn femur was. When BCNIs were cultured for 48 hours in BGJ media containing 35SO4 or 14C-glucosamine, -Zn BCNIs incorporated significantly more 14C and slightly higher 35S into their glycosaminoglycan (GAG) fraction. It is concluded that under our standardized conditions zinc deficiency does not show an effect on Ca and P depositions into bone, but it seems to interfere with glycosaminoglycan metabolism of membranous bone.

Biosynthesis of dimethyl selenide from sodium selenite in rat liver and kidney cell-free systems.

A pathway for the synthesis of dimethyl selenide from sodium selenite was studied in rat liver and kidney fractions under anaerobic conditions in the presence of GSH, a NADPH-generating system, and S-adenosylmethionine. Chromatography of liver or kidney soluble fraction on Sephadex G-75 yielded a Fraction C (30,000 molecular weight) which synthesized dimethyl selenide, but at a low rate. Addition of proteins eluting at the void volume (Fraction A) to Fraction C restored full activity. Fractionation of Fraction A on DEAE-cellulose revealed that its ability to stimulate Fraction C was associated with two fractions, one containing glutathione reductase and the other a NADPH-dependent disulfide reductase. It was concluded that Fraction C contains a methyltransferase acting on small amounts of hydrogen selenide produced non-enzymically by the reaction of selenite with GSH, and that stimulation by Fraction A results partly from the NADPH-linked formation of hydrogen selenide catalyzed by glutathione reductase present in Fraction A. Washed liver microsomal fraction incubated with selenite plus 20 mM GSH also synthesized dimethyl selenide, but addition of soluble fraction stimulated activity. A synergistic effect was obtained when liver soluble fraction was added to microsomal fraction in the presence of a physiological level of GSH (2 mM), whereas at 20 mM GSH the effect was merely additive. The microsomal component of the liver system was labile, had maximal activity around pH 7.5, and was exceedingly sensitive to NaAsO2 (93% inhibition by 10(-6) M arsenite in the presence of a 20,000-fold excess of GSH). The microsomal activity apparently results from a Se-methyltransferase, possibly a dithiol protein, that methylates hydrogen selenide produced enzymically by the soluble fraction or non-enzymically when a sufficiently high concentration of GSH is used.

Effects of stock or purified diet on rat liver enzymes involved in the synthesis of dimethyl selenide.

Rats fed either a stock deit or a purified diet based on casein were tested for their ability to convert 75Se-sodium selenite to volatile selenium (dimethyl selenide) in vivo. This conversion was also studied in liver and kidney in vitro. When injected with a subacute dose of selenite (2 mg Se/kg), rats previously fed stock diet volatilized more than twice as much of the dose compared to rats fed the purified diet, confirming earlier findings. Parallel dietary effects were also observed in vitro using subcellular fractions incubated with 75Se-selenite, glutathione, TPNH, and S-adenosylmethionine. The 9-000 X g supernate prepared from rats fed stock diet synthesized dimethyl selenide at approximately twice the rate of that prepared from rats fed purified diet. A fourfold higher activity was observed with liver microsomal fractions from rats fed the stock diet, whereas cytosol was slightly more active in rats fed the purified diet. Kidney fractions showed analogous changes with diet, although the activity of kidney microsomal fraction was very low. Only minor differences in the levels of glutathione reductase, nonspecific disulfide reducatse, and non-protein thiols were observed in liver and kidney from rats fed the two diets. Considering the effects of diet on the various enzymes known from our previous studies to be involved in dimethyl selenide synthesis, it was concluded that the enhanced ability of rats fed stock diet to synthesize dimethyl selenide results from the induction of a liver microsomal enzyme, apparently a Se-methyltransferase, caused by unknown substances in the stock diet.

Ceruloplasmin: the copper transport protein with essential oxidase activity.

Ceruloplasmin, the blue copper-protein of vertebrate plasma, has been reviewed mainly from a functional point of view. However we have surveyed the chemistry and state copper in the molecule because of the implications of the recent data of Ryden (13,28). His observations suggest that unless special precautions are taken in the isolation of ceruloplasmin degradation, probably proteolytic, produces fragments of various sizes. When isolated, these fragments appear to be held together by noncovalent interactions. Comparison of their catalytic and spectral properties reveals no significant differences from a single homogeneous species of molecular weight of 134,000 isolated by Ryden's methods. On the other hand, the homogeneous molecule may differ in properties highly sensitive to conformation and three-dimensional parameters. Three types of copper atoms have been identified in ceruloplasmin, but their amino acid environment is still unknown. Ceruloplasmin possesses significant oxidase activity towards Fe(II) and numerous aromatic amines and phenols. Its ferroxidase activity has led to the discovery that it is a molecular link between copper and iron metabolism. Ceruloplasmin mobilizes iron into the plasma from iron storage cells in the liver. An equally important duty is that ceruloplasmin, after its rapid biosynthesis in the liver, serves as a major copper transport vehicle, comparable to transferrin. Evidence is accumulating that the copper atoms of ceruloplasmin are a prerequisite for copper utilization in the biosynthesis of cytochrome oxidase and other copper proteins. The ability of ceruloplasmin to release copper at specific cellular sites may be related to its broad substrate spectrum of biological reducing agents. A possible third role of ceruloplasmin is as a contributor to the regulation of the balance of biogenic amines through its oxidase action on the epinephrine and the hydroxyindole series. Thus ceruloplasmin is a copper-protein with several important functions, all of which are directly related to its oxidase activity.

The biological role of ceruloplasmin and its oxidase activity.

Ceruloplasmin (ferroxidase) the blue Cu-protein of vertebrate plasma, possesses significant oxidase activity towards Fe(II) and numerous aromatic amines and phenols. Its ferroxidase activity has led to the discovery that it is a molecular link between copper and iron metabolism. Ceruloplasmin mobilizes iron into the plasma from iron storage cells in the liver. An additional role of Cp may be as a contributor to the regulation of the balance of biogenic amines through its oxidase action on the epinephrine and the hydroxyindole series. Ceruloplasmin also serves as a major copper transport vehicle, comparable to transferrin for iron. Evidence is presented that the copper atoms of Cp are a prerequisite for copper utilization in the biosynthesis of cytochrome oxidase. The ability of Cp to release copper at specific cellular sites is believed to be related to its broad substrate spectrum of biological reducing agents. Thus Cp is a serum protein with several important functions, all of which are directly related to its oxidase activity.

Acid-volatile selenium formation catalyzed by glutathione reductase.

The production of acid-volatile selenide (apparently H2Se) was catalyzed by glutathione reductase in an anaerobic system containing 20 mM glutathione, 0.05 mM sodium selenite, a TPNH-generating system, and microgram quantities of highly purified yeast glutathione reductase. H2Se production in this system was proportional to glutathione reductase concentration and was maximal at pH 7. Significant nonenzymic H2Se production occurred in the system lacking glutathione reductase and TNPH. A concentration of arsenite (0.1 mM) which does not inhibit glutathione reductase inhibited selenide volatilization, as did bovine serum albumin (1.67 mg/ml). Both appear to inhibit Se volatilization by reacting with the selenide product(s). The selenotrisulfide derivative of glutathione (GSSeSG) was readily converted to H2Se by glutathione reductase and TPNH without the addition of glutathione. These results suggest that GSSeSG formed nonenzymically from glutathione and selenic undergoes stepwise reduction by glutathione reductase (or excess GSH) to GSSeH and finally to H2Se. The same pathway operates when glutathione is used as the reducing agent but to a lesser extent.

Electrophoretic and functional variants of NADH-methemoglobin reductase in hereditary methemoglobinemia.

The electrophoretic mobility and activity of NADH-methemoglobin reductase in erythrocytes of patients with hereditary methemoglobinemia, obligatory heterozygotes, and normal subjects were examined. Six distinct electrophoretic variants were found in studies of erythrocytes from members of ten different families. Five variants (Boston Slow, Duarte, Princeton, Puerto Rico, and California) were associated with significant methemoglobinemia and moderate to marked decreases in enzymic activity. Precise correlations between levels of NADH-methemoglobin reductase activity, electrophoretic mobility, and clinical severity of methemoglobinemia, however, could not be drawn. One variant (Boston Fast) was associated with almost normal activity and very minimal methemoglobinemia. Nine members from three generations of two Italian families were found to have two bands with NADH-methemoglobin reductase activity in their erythrocytes, one with normal mobility and one with a mobility identical with that of Boston Fast. No functional or clinical impairment could be attributed to this abnormality. The observations made in this investigation were consistent with an autosomal recessive mode of inheritance of multiple alleles for NADH-methemoglobin reductase. As has been shown to be true for hemoglobin and glucose-6-phosphate dehydrogenase, multiple aberrations in the NADH-methemoglobin reductase of human erythrocytes apparently exist, some with and some without functional consequences. Two bands with NADPH-methemoglobin reductase activity with electrophoretic mobilities distinct from those of the NADH-methemoglobin reductase were found in human erythrocytes. These bands were normal in hemolysates of erythrocytes from patients with hereditary methemoglobinemia, but were absent from the hemolysate of erythrocytes deficient in NADPH-methemoglobin reductase activity. These latter erythrocytes, however, contained normal concentrations of methemoglobin and had a normal ability to reduce methemoglobin in vitro. These observations were most consistent with the thesis that the NADH-methemoglobin reductase, distinct from any NADPH-methemoglobin reductase, was the major system responsible for the reduction of methemoglobin to hemoglobin in human erythrocytes.