Increasing intakes of iron reduce status, absorption and biliary excretion of copper in rats

High intakes of Fe may impair Cu status, but the underlying mechanism is not known. Male rats, aged 7 weeks, were given purified diets adequate in Cu (8 mg Cu/kg) and containing either 7, 40 or 389 mg Fe/kg. After 6 weeks the concentrations of Fe in liver and spleen were positively related with dietary Fe level and those of Cu were negatively related with dietary Fe level. Increasing Fe intakes reduced apparent absorption and biliary excretion of Cu in a dose-dependent fashion. In individual rats, biliary Cu excretion showed a significant, positive correlation with liver Cu concentration. It is concluded that increased Fe intakes depress Cu absorption which produces a decrease in plasma and organ Cu concentrations. As a result, biliary Cu excretion is lowered which contributes to achieving Cu balance at high Fe intakes. Because the concentrations of Cu in plasma and bile, and also plasma ceruloplasmin (EC 1.16.3.1) activities, showed much greater percentage reductions with increasing Fe intake than did the concentrations of Cu in organs, it is possible that increased Fe status interferes with the mobilization of Cu stores.

Dietary ascorbic acid lowers the concentration of soluble copper in the small intestinal lumen of rats

We tested the hypothesis that ascorbic acid in the diet of rats lowers the concentration of soluble Cu in the small intestine, causing a decrease in apparent Cu absorption. Male rats were fed on diets adequate in Cu (5 mg Cu/kg) without or with 10 g ascorbic acid/kg. The diet with ascorbic acid was fed for either 6 or 42 d. Ascorbic acid depressed tissue Cu concentrations after a feeding period of 42, but not after 6 d. Dietary ascorbic acid lowered apparent Cu absorption after 6, but not after 42 d. The lowering of tissue Cu concentrations after long-term ascorbic acid feeding may have increased the efficiency of Cu absorption, and thus counteracted the inhibitory effect of ascorbic acid. Dietary ascorbic acid caused a significant decrease in the Cu concentrations in the liquid phase of both the proximal and distal parts of the small intestinal lumen. This effect was due to both a decrease in the amount of Cu in the liquid digesta and an increase in the volume of the liquid phase; only the latter effect for the distal intestine was statistically significant. We conclude that ascorbic acid supplementation lowers Cu absorption by decreasing the concentration of soluble Cu in the small intestine.

Comparison between time-dependent changes in iron metabolism of rats as induced by marginal deficiency of either vitamin A or iron

To compare the changes in Fe metabolism during the development of vitamin A and Fe deficiencies, rats were given either a control diet with sufficient Fe (35 mg added Fe/kg feed) and retinol (1200 retinol equivalents/kg feed), a diet without added vitamin A or a diet with sufficient vitamin A but only 3.5 mg added Fe/kg feed. During a period of 10 weeks, indicators of vitamin A and Fe status were monitored. Neither vitamin A nor Fe deficiency produced clinical signs. Fe deficiency induced an immediate fall in blood haemoglobin concentration. Vitamin A deficiency produced a mild anaemia as the first change in Fe metabolism, pointing to impaired erythropoiesis. This effect was followed by a rise in Fe absorption and an increased amount of Fe in the spleen. By the end of the study, blood haemoglobin, packed cell volume, plasma Fe and Fe content in kidney and femur had increased above control levels, while total Fe-binding capacity had decreased. We speculate that the initial anaemia was masked later by haemoconcentration. The decrease in Fe mobilization, shown by lower total Fe-binding capacity, and the increase in Fe absorption may have caused the observed continuous rise in tissue Fe concentration in rats with vitamin A deficiency. In the rats with Fe deficiency, low tissue Fe levels coincided with high Fe absorption and high total Fe-binding capacity. Thus, changes in Fe metabolism with vitamin A deficiency differed from those with Fe deficiency.

[Chronic empyema associated with large cell carcinoma of lung: case report with review of the literature]

A 71-year-old female was seen with a complaint of chest pain and cough, and a history of tuberculous pleurisy and artificial pneumothorax 40 years ago. The diagnosis of empyema with carcinoma was made by chest X-ray and CT scans. The examination of lung function showed a restrictive disorder. The value of the predicted postoperative FEV1 0.75 l encouraged to perform operation. A left pleuropneumonectomy and combined resections of the invasive portion of the pericardium and left atrium was performed. Histological examination revealed large cell carcinoma of lung (pT 4 N 1 M 0). The literatures are reviewed concerning the thoracic malignant tumor arising in chronic empyema cavity on Japanese cases.

Ascorbic acid feeding of rats reduces copper absorption, causing impaired copper status and depressed biliary copper excretion

The feeding of diets enriched with ascorbic acid (10 g/kg) to rats has previously been shown to lower plasma and liver copper concentrations. The present studies corroborate this. We hypothesized that ascorbic acid initially reduces copper absorption, this effect being masked later by the stimulatory effect on copper absorption of the impaired copper status. We also hypothesized that the impaired copper status as induced by ascorbic acid feeding is followed by a diminished biliary excretion of copper in an attempt to preserve copper homeostasis. Our hypotheses are supported by the present studies. Ascorbic acid feeding initially reduced apparent copper absorption, and in the course of the experiment this effect tended to turn over into a stimulatory effect. Copper deficiency, as induced by feeding a diet containing 1 mg Cu/kg instead of 5 mg Cu/kg, systematically increased copper absorption. Biliary excretion of copper in rats given ascorbic acid was unaffected initially but became depressed after prolonged ascorbic acid feeding. A similar time course was seen for fecal endogenous copper excretion that was calculated as the difference between true and apparent copper absorption. Copper deficiency systematically reduced biliary copper excretion and fecal endogenous copper loss.

[Interaction among the relative risk factors of primary liver cancer in a case-control study]

This paper evaluates the combined effect of HBsAg, drinking water and aflatoxin B1 (AFB1) on the primary hepatocellular carcinoma (PHC) in a case-control study which was carried out in Fusui, Guangxi. We used relative risk model (from subadditive to supermultiplicative) to fit the relationship. The results showed that the combined effect of HBsAg infection and drinking pond-ditch water is nearly multiplicative, and the combined effect of HBsAg infection and AFB1 intake as well as drinking pond-ditch water and AFB1 intake were nearly additive.

Myocutaneous flaps in genitourinary oncology

Between January 1983 and September 1992, 32 myocutaneous flaps were fashioned in 28 patients for reconstruction following treatment of genitourinary malignancies or complex pelvic fistulas. Of the myocutaneous flaps 14 were used to obtain primary soft tissue coverage of large but otherwise uncomplicated wounds and 10 were used to cover previously irradiated resection sites. Four myocutaneous flaps were used to repair complex radiation-induced fistulas involving the bladder, vagina, urethra and rectum. Flaps were used to cover infected or nonhealing open wounds in 8 cases, 4 of which also had been previously irradiated. Myocutaneous flap donor sites were the tensor fascia lata in 11 cases, gracilis in 9, rectus abdominis in 10 and rectus femoris in 2. There was 1 major complication (flap loss) and 9 minor complications. There were no perioperative deaths. Myocutaneous flaps are an effective means of covering large groin, perineal and lower abdominal surgical defects after radical surgery.

[Epidemiological study on risk factors of cervical cancer]

The relationship between cervical cancer and risk factors including virus infection of cervix was studied with methods of molecular and serological epidemiology. DNA extracted from cervical biopsies taken from 57 cases and 51 controls were tested for HPV6/11, HPV16/18 by Dot-blot hybridization and for HSV-2 by PCR. Sera were detected for HCMV-IgM by ELISA. The results and risk factors were analyzed by logistic regression model. The multiple logistic regression model results showed that HPV16/18 infection was an important risk factor, the infection rate was significantly higher in the group of cervical cancer, the OR was 31.96. Other risk factors were the educational level and the number of birth, the OR were 0.57 and 1.85, respectively. The difference of HSV-2 infection of cervix and HCMV-IgM in serum was not significant between the two groups.

Recombinant soluble human thrombomodulin: a randomized, blinded assessment of prevention of venous thrombosis and effects on hemostatic parameters in a rat model

Thrombomodulin is an endothelial surface receptor that binds thrombin and accelerates the activation of protein C. We compared the effects of a recombinant thrombomodulin analog (TME), recombinant hirudin (r-HIR), heparin sodium (HEP), and normal saline (Control) on thrombus formation, activated partial thromboplastin time (APTT), thrombin time (TT), platelet aggregation and tail transection bleeding time (BT) in a rat model of vena cava thrombosis.

RESULTS

TME, r-HIR and HEP prevented venous thrombosis in this model in a dose-dependent manner. At the dose required to reduce vena cava thrombosis by 50% (ED50), TME did not prolong the APTT or TT as did HEP and r-HIR. Platelet aggregation in response to thrombin was not effected by TME but was inhibited by both r-HIR and HEP. BT did not differentiate the agents tested.

CONCLUSION

TME inhibited venous thrombosis in a rat vena cava model with less effect on hemostatic variables than HEP or r-HIR.

The in vitro pharmacology of SC-51146: a potent antagonist of leukotriene B4 receptors

Previously, we reported that SC-41930 is a potent leukotriene B4 (LTB4) receptor antagonist. An analog of SC-41930, SC-51146, was evaluated as an antagonist of LTB4 receptors. SC-51146 was shown to bind to LTB4 high affinity binding sites on human neutrophils (PMN) with a dissociation constant (KD) value of 1.5 +/- 0.1 nM, compared to 19 +/- 1.3 nM for SC-41930. PMN chemotaxis studies and Scatchard analyses of [3H]LTB4 binding in PMN membranes indicated that SC-51146 acted as a competitive antagonist. The IC50 value of SC-51146 for the inhibition of PMN chemotaxis induced by 30 nM LTB4 was 38 +/- 12 nM. SC-51146 inhibited PMN degranulation induced by 50 nM LTB4 with an IC50 value of 29 +/- 7 nM. The antagonism by SC-51146 of LTB4-induced PMN degranulation appeared to be noncompetitive. The specificity of SC-51146 for LTB4 receptors vs. fMLP receptors was improved approximately 29 and 44 times over SC-41930. SC-51146 showed relatively weak inhibitory activity on the production of superoxide, LTB4 and/or prostaglandin E2 by human PMN or HL-60 cells. SC-51146 had little activity on ram seminal vesicle cyclooxygenase, and no activity on porcine pancreatic phospholipase A2. SC-51146 is a racemate comprised of the (+) enantiomer, SC-53228, and the (-) enantiomer, SC-53229. Both stereoisomers exhibited pharmacological profiles similar to SC-51146 in these aforementioned in vitro systems. The highly potent and specific antagonistic action of SC-51146 on LTB4 receptors should be particularly useful in elucidating the role of LTB4 in the pathogenesis of inflammatory diseases where excessive levels of LTB4 have been reported.

Construction, expression, and properties of a recombinant chimeric human protein C with replacement of its growth factor-like domains by those of human coagulation factor IX

The cDNA encoding a chimeric human protein C (PC), in which its epidermal growth factor-(EGF) like regions have been replaced with equivalent structures from human factor IX (fIX), was constructed and the gene product was expressed in human 293 cells. A molecular subpopulation of the recombinant chimeric protein (r-[PC/delta EGF-1,2/delta fIXEGF-1,2]) was purified that contained the full complement (9 residues/mol) of gamma-carboxyglutamic acid (Gla). After conversion by thrombin to its activated form (r-[APC/delta EGF-1,2/delta fIXEGF-1,2]), this latter enzyme was found to possess approximately 10% of the activity of wild-type recombinant APC (wtr-APC) in an APTT assay. In assay systems employing purified components, the activity of the mutant enzyme toward prothrombinase cofactor Va (fVa) and tenase cofactor VIII (fVIII) was approximately 30% and < 10%, respectively, of that of wtr-APC. The chimeric protein displayed full reactivity with a Ca(2+)-dependent monoclonal antibody to the Gla domain of PC, yielding a C50 for Ca2+ that was very similar to that obtained with wtr-PC (ca. 3.7 mM). Titrations of the dependency on Ca2+ of the intrinsic fluorescence of r-[PC/delta EGF-1,2/delta fIXEGF-1,2] allowed calculation of a C50 value of 0.34 mM, again very similar to that of wtr-PC. As with wtr-PC, Ca2+ inhibited the thrombin-catalyzed activation of r-[PC/delta EGF-1,2/delta fIXEGF-1,2] with aKi of 148 microM, as compared to a Ki of 125 microM for wtr-PC. At a saturating level of Ca2+, activation of r-[PC/delta EGF-1,2/delta fIXEGF-1,2/] by the thrombin/thrombomodulin (thrombin/TM) complex occurred at approximately 70% of the rate of that of wtr-PC.(ABSTRACT TRUNCATED AT 250 WORDS)

Fragile X syndrome unstable element, p(CCG)n, and other simple tandem repeat sequences are binding sites for specific nuclear proteins

The trinucleotide repeat sequences which become unstable in fragile X syndrome and myotonic dystrophy are located in the untranslated regions of their respective genes, FMR1 and DM1. This implies that a functional constraint other than coding capacity maintains the presence of the repeats. In the case of fragile X syndrome, sequences adjacent to the repeat are methylated in affected individuals and the FMR1 gene is transcriptionally inactive. We demonstrate that the fragile X p(CCG)n repeat itself is methylated in vivo and that methylation of this repeat is able to inhibit in vitro binding of a novel, specific nuclear p(CCG)n binding protein (CCG-BP1)--one of at least 10 distinct simple tandem repeat sequence binding proteins (STR-BPs). We describe additional, apparently distinct, binding activities both for the methylated form of the p(CCG)n repeat and for each of the single strands of the repeat.

Dietary fructose vs glucose lowers copper solubility in the digesta in the small intestine of rats

The hypothesis was tested that dietary fructose vs glucose lowers copper solubility in the digesta in the small intestine of rats, which in turn causes a decreased copper absorption. Male rats were fed adequate-copper (5 mg Cu/kg) diets containing either fructose or glucose (709.4 g monosaccharide/kg) for a period of 5 wk. Fructose vs glucose significantly lowered copper concentrations in plasma and the liver, but did not alter hepatic copper mass. Fructose feeding resulted in a significantly lesser intestinal solubility of copper as based on either a smaller soluble fraction of copper in the liquid phase of small intestinal contents or a lower copper concentration in the liquid phase. The latter fructose effect can be explained by the observed fructose-induced increase in volume of liquid phase of intestinal digesta. After administration of a restricted amount of diet extrinsically labeled with 64Cu, rats fed fructose also had significantly lower soluble 64Cu fraction in the digesta of the small intestine. Although this study shows that fructose lowered intestinal copper solubility, only a slight reduction of apparent copper absorption was observed. It is suggested that the fructose-induced lowering of copper status in part counteracted the fructose effect on copper absorption at the level of the intestinal lumen.

[Anoxia-reperfusion injury to endothelial cells: mechanism and protection]

Endothelial cells in the aortic walls of inbred SD rats were cultured in MEM culture medium containing 10% calf serum, and an anoxia-reperfusion injury model was established. The effect of anoxia-reperfusion injury on cultured endothelial cells was studied by measurements of membrane fluidity, intracellular Ca content, the release rate of 51Cr and the uptake rate of trypan-blue. The effect of fructose 1-6 diphosphate (FDP) and captopril (Cap) on cultured endothelial cells was also investigated. The findings indicated that the two drugs might protect cultured endothelial cells from anoxia-reperfusion injury. The mechanism of anoxia-reperfusion injury and the protective effect of the two drugs on cultured endothelial cells were briefly discussed.

Intrathymic injection of donor alloantigens induces specific tolerance to cardiac allografts

The induction of donor-specific tolerance would eliminate the risk of long-term immunosuppression while ensuring allograft function and survival. Male Buffalo (RT1b) rats were exposed to donor alloantigen by an intrathymic, intrasplenic, s.c., or i.v. injection of 25 x 10(6) syngeneic Buffalo (RT1b) or MHC fully mismatched Lewis (RT1l), ACI (RT1a), or UV-B irradiated Lewis (RT1l) splenocytes. The Buffalo recipients were given 1 cc of rabbit antirat antilymphocyte serum (ALS) i.p. at the time of the donor antigen injection, and 21 days later received a heterotopic Lewis or ACI heart transplant. Only intrathymic alloantigen injection induced a donor-specific tolerance which allowed the cardiac allograft to survive indefinitely (mean survival time [MST] > 176.8 days) in > 86% of the recipients without the need for further immunosuppression, whereas groups receiving antigen injections at other sites rejected cardiac allografts in control time (MST approximately 7.0 days). Histologic examination of long-term tolerated Lewis cardiac allografts revealed the presence of healthy cardiac myocytes without mononuclear infiltration. Buffalo rats with a long-term surviving Lewis cardiac allograft did not reject a second Lewis cardiac allograft (MST > 100.0 days), but rejected a heterotopic ACI cardiac allograft in normal time (MST approximately 7.0 days). By limiting dilution analysis (LDA), maturation of donor-specific CTLs (pCTL) from long-term recipient splenocytes was markedly diminished, whereas third party pCTL was not altered, and T helper-precursors were moderately decreased without alteration in the peripheral CD4+ and CD8+ phenotype frequencies. MLC responses of recipients with long-term surviving cardiac allografts to donor-specific and third party stimulation were not significantly different from naive controls. Microchimerism is unlikely because Lewis allograft survival was also prolonged (MST > 96.0 days) in rats receiving UV-B irradiated Lewis splenocytes which cannot proliferate. The absence of increased allograft survival after transfer of long-term recipient splenocytes into naive animals suggests that donor-specific suppressor cells are not present. Additionally, in vitro lymphocyte proliferative responses to mitogenic or allogeneic stimulation in MLC was not diminished by the addition of these long-term recipient splenocytes. This model emphasizes the importance of exposure of T cell precursors to foreign donor alloantigen in the thymic environment for the development of unresponsiveness to a donor-specific vascularized allograft.

Leukotriene B4-induced granulocyte trafficking in guinea pig dermis. Effect of second-generation leukotriene B4 receptor antagonists, SC-50605 and SC-51146

Leukotriene B4 (LTB4) is a proinflammatory product of arachidonic acid metabolism that has been implicated as a mediator in a number of inflammatory diseases. When injected intradermally into the guinea pig, LTB4 elicits a dose-dependent migration (chemotaxis) of neutrophils (PMNs) into the injection sites as assessed by the presence of a neutrophil marker enzyme myeloperoxidase. SC-41930 (7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]-3,4-dihydro-8-p ropyl-2H-1-benzopyran-2-carboxylic acid), a first-generation LTB4 receptor antagonist inhibited the chemotactic actions of LTB4 when coadministered into the dermal site and when given orally with ED50 values of 340 ng and 1.7 mg/kg, respectively. The second-generation LTB4 receptor antagonists SC-50605 (7-[3-[2(cyclopropylmethyl)-3-methoxy-4-(4-thiazolyl)phenoxy]propoxy]- 3,4-dihydro-8-propyl-2H-1-benzopyran-2-carboxylic acid) and SC-51146 (7-[3-[2(cyclopropylmethyl)-3-methoxy-4-[(methylamino)carbonyl] phenoxy]propoxy]-3,4-dihydro-8-propyl-2H-1-benzopyran-2-propanoic acid) inhibited LTB4-induced chemotaxis when coadministered with ED50 values of 70 ng and 32 ng, respectively, and when given intragastrically with ED50 values of 0.10 and 0.09 mg/kg, respectively. SC-41930, SC-50605, and SC-51146 had oral durations of action of 5.5, 15, and 21 h, respectively. These potent, LTB4 receptor antagonists may well have application in the medical management of disease states such as asthma, rheumatoid arthritis, inflammatory bowel disease, contact dermatitis, and psoriasis, where LTB4 is implicated as an inflammatory mediator.

Alpha-1,4-glucan lyase, a new class of starch/glycogen degrading enzyme. I. Efficient purification and characterization from red seaweeds

This study presents the first purification and characterization of an alpha-1,4-glucan lyase. The enzyme degraded alpha-1,4-glucan to produce 1,5-anhydrofructose. A simple and efficient purification procedure has been developed and the enzyme has been purified to homogeneity from two red seaweeds Gracilariopsis lemaneiformis and Gracilaria verrucosa. alpha-1,4-Glucan lyase was apparently a single polypeptide as a molecular weight of 111,000 was observed in SDS-gel electrophoresis, and 98,000 by gel filtration chromatography on Sephacryl S-200. Amino acid composition analysis of the enzyme showed high amounts of Asp/Asn, Gly and Glu/Gln. The isoelectric point of the enzyme was 3.9, as revealed by isoelectrofocusing. The concentrations of maltotriose, maltose and amylopectin that yield half of the maximum activity were 798 micrograms ml-1 (1.58 mM), 1,418 micrograms ml-1 (4.14 mM) and 1,600 micrograms ml-1, respectively. alpha-1,4-Glucan lyase exhibited a wide pH optimum range from pH 2.5 to 7.0 for maltose and from pH 3.5 to 7.5 for amylopectin. The optimal temperature for activity of the algal lyase was 50 degrees C when maltose or amylopectin was used as a substrate under the assay conditions. The Arrhenius activation energies were 45.8 and 44.0 kJ mol-1 for maltose and amylopectin as substrate, respectively. Only one form of alpha-1,4-glucan lyase was found in cell-free extracts of the two red seaweeds.

Haptoglobin types in Chinese ethnic groups

The distribution of haptoglobin (HP) types was examined in six different Chinese ethnic groups. The gene frequencies were compared among these groups and to those reported in other Chinese Han populations. The effects of sex and age on the distribution of HP types are also discussed.