[Relation of habitual exercise to basal metabolic rate and energy expenditure during exercise in older people]

The relation between habitual exercise and the basal metabolic rate, energy expenditure during exercise (lactic threshold and maximal oxygen uptake) was examined in 291 older people. Metabolic rate was highest in old players of gatebowl (a form of croquet) (male; 23.3 +/- 2.3, female; 22.7 +/- 3.0 kcal/kg/day), higher in old untrained people (male; 21.9 +/- 2.5, female; 20.8 +/- 2.4 kcal/kg/day), and lower in old people in a home for the aged (male; 20.6 +/- 3.5, female; 20.8 +/- 3.7 kcal/kg/day). Energy expenditure while walking at a speed of less than 100 m/min was similar in trained and untrained old people aged 60-69 years. However, lactic threshold was higher in trained (30.2 +/- 4.8 ml/kg/min) than in untrained (20.9 +/- 2.8 ml/kg/min) females aged 60-69 years. Maximal oxygen uptake was higher in trained (male; 50.4 +/- 4.1, female; 36.6 +/- 3.9) than in untrained (male; 30.9 +/- 3.7, female; 26.8 +/- 2.8) old people aged 60-69 years. It was suggested that a higher basal metabolic rate, lactic threshold and maximal oxygen uptake resulted in higher daily physical activity and larger daily energy consumption in trained old people.

[Pharmacokinetics of MX2, a new morpholino anthracycline, in CSF following intravenous injection]

MX2 x HCl is a new morpholino anthracycline derivative with molecular weight 622.07, and highly lipophilic. In the animal experiments, MX2 was found to cross the blood brain barrier after i.v. injection. Its distribution into the brain was increased by intracarotid injection. In the present study, we examined the distribution of MX2 into the cerebrospinal fluid (CSF) after i.v. administration (5 mg/kg) in normal rabbits. Five min after injection, plasma concentration of MX2 reached to the maximum level (4344.5 ng/ml). CSF concentration of MX2 was at the highest level (75.8 ng/ml) 10 min after injection, and thereafter decreased gradually in parallel with plasma concentration. At 5 hrs after injection, CSF concentration became 26.7 ng/ml, AUC half time of elimination, and mean residence time were 3093.8 ng.hr/ml, 4.57 hrs and 5.10 hrs in plasma and 212.3 ng.h/ml, 5.23 hrs and 7.14 hrs in CSF, respectively. These results indicate that MX2 is able to distribute into CSF after i.v. injection, and expected to be a new anticancer drug for brain and leptomeningeal tumors.

Identification of human T cell hybridoma-derived macrophage activating factor as interleukin-2

Macrophages are activated by a two-step mechanism involving at least two kinds of factors, a priming and a triggering factor, to become cytotoxic to various tumor cells. In the present study, we purified macrophage-activating factor for cytotoxicity I (MAF-C I), defined as a priming macrophage activating factor (MAF), by about 1,600-fold from the culture supernatant of a human T cell hybridoma, H3-E9-6, by a series of chromatographic procedures. We identified MAF-C I activity released from H3-E9-6 cells as interleukin-2 (IL-2) from the following findings. (i) The physicochemical properties of MAF-C I and IL-2 were almost identical. (ii) Purified MAF-C I active fraction also showed T cell proliferating activity. (iii) MAF-C I activity in the purified fraction was completely neutralized by anti-IL-2 antibodies. (iv) Human recombinant IL-2 (rIL-2), at a suboptimal dose, and lipopolysaccharide (LPS) synergistically induced monocyte-mediated cytotoxicity.

Regulation of two forms of the TNF receptors by phorbol ester and dibutyryl cyclic adenosine 3',5'-monophosphate in human histiocytic lymphoma cell line U-937

Recently the cDNA for two different forms of TNF receptor, with gene products of molecular masses of 60 and 80 kDa, have been cloned. In the present report, we investigated the effects of phorbol ester and dibutyryl cAMP on the regulation of the transcript for each type of TNF receptor in U-937 cells. Our results indicate that exposure of these cells to either phorbol ester or dibutyryl cAMP increases the steady state mRNA levels of the 80 kDa form. This effect is dose- and time-dependent. The induction of the p80 receptor transcript by PMA and dibutyryl cAMP was additive suggesting independent mechanisms of induction. Under identical conditions, both agents failed to induce the transcript for the p60 form of the TNF receptor. As demonstrated by actinomycin D pulse-chase experiment, the mRNA for the p80 receptor was found to be highly stable with an approximate half-life of 16 h. No significant change in the half-life was observed when cells were treated with phorbol ester. The mechanisms by which phorbol ester and dibutyryl cAMP induce the upregulation of p80 receptor mRNA appear to be different. Induction of receptor transcript by cycloheximide suggests the presence of a labile repressor protein. Interestingly, the effect of cycloheximide on the induction of the p80 mRNA was found to be additive with that of dibutyryl cAMP but not with phorbol ester. 1-(5-Isoquinolinylsufonyl)-2-methylpiperazine (H7) and N[2-(methylamino) ethyl]-5-isoquinolinesulfonamide (H-8), inhibitors of protein kinase C and protein kinase A, respectively, both inhibited the phorbol ester-mediated induction of the p80-transcript but not that mediated through dibutyryl cAMP. Since dibutyryl cAMP undergoes intracellular dissociation into cAMP and butyric acid, we found that exposure of cells to sodium butyrate alone could induce p80 mRNA in a dose-dependent manner, thus suggesting the role of histone hyperacetylation. Furthermore forskolin treatment, an intracellular inducer of cAMP, increased the receptor transcript level whereas isobutylmethylxanthine, an inhibitor of phosphodiesterase, had no effect. Interestingly, while the p80 form of the TNF receptor mRNA levels was elevated by both phorbol ester and dibutyryl cAMP, only dibutyryl cAMP increased the TNF binding; phorbol ester treatment decreased the binding activity. Thus, our results demonstrate that the genes for the two forms of TNF receptors are differentially regulated. Furthermore, the mechanism of regulation by PMA differs from that by dibutyryl cAMP.

Inhibition of tyrosine activity by cultured lichen tissues and bionts

Axenic, cultured thallus tissues from forty-six species of lichens were evaluated for their inhibitory effect on tyrosinase activity. Methanol extracts of tissues of three lichens, i.e. HYPOGYMNIA PHYSODES, LETHARIA VULPINA, and CETRARIA JUNIPERINA strongly inhibited tyrosinase activity, but extracts from the corresponding natural thalli showed only weak inhibition. The mycobiont of HYPOGYMNIA PHYSODES showed a higher inhibitory action than its photobiont.

Pharmacokinetics of temocapril, an ACE inhibitor with preferential biliary excretion, in patients with impaired liver function

Six subjects with normal liver function (Group 1) and 7 patients with liver dysfunction (Group 2; mean ICGR15 value 30.5 (5.2)%; range 16 to 56) received a single oral dose of 1 mg temocapril, a prodrug-type ACE inhibitor, with preferentially excreted by the biliary route. The plasma temocapril concentrations in Group 2 at 30 min and 1 h postdose were significantly higher than in Group 1, but the difference had disappeared 2 h postdosing. Although the half life of temocapril diacid in Group 2 was significantly longer than in Group 1, there was no significant difference between the two groups in AUC, Cmax or tmax. In Group 2, urinary recovery of temocapril was significantly increased, suggesting a possible delay in the bioactivation of temocapril into the diacid, but recovery of the diacid itself was not abnormal. ACE inhibitory action in Group 2 remained unchanged. Temocapril is regarded as an ACE inhibitor the disposition and efficacy of which are little affected in patients with impaired liver function.

[In vitro ENU-induced carcinogenesis of rat fetal astroglia--biological character of mutant glial cell]

To investigate glial carcinogenesis in vitro, fetal rat brain cells were cultured and exposed to ENU (approximately 200 micrograms/ml). The cells were passaged weekly thereafter. Morphological changes were observed under the phase contrast microscope. When mutant colonies where the cells lost contact inhibition and grew in a multilayer fashion appeared, the cells were cloned. To assess the biological characters of cells, expression of GFAP, vimentin, A2B5 and p53 product were determined by immunohistochemistry and flow cytometry. Tumor forming ability of the cells was evaluated by both colony forming efficiency in low serum medium (LSM; 2% FBS, 300 cells/100 mm dish) and transplantability to nude mice. Both primary cultured and ENU-treated cells were positive for GFAP and vimentin, but population of A2B5 positive cells was less than 5%, thus indicating that these cells were astroglial in origin. The mutant colonies appeared 7 weeks after ENU treatment. These cells grew rapidly with cell doubling time ranging between 18 to 26 hours, while non-ENU-treated astroglias had a longer cell doubling time (48 to 55 hours). The cloned mutant glial cell lines formed large colonies in LSM (efficiency 20-40%), but astroglial cells did not. The mutant astroglial cells also developed tumors in nude mice. p53 protein was never detected in normal astroglia, however, some glial cells treated by ENU abruptly became p53 positive after several passages. These p53 positive cells formed stratified colonies thereafter. These results indicate that mutant astroglial cells can be induced by a single dose of ENU in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of tenascin in human gliomas: its relation to histological malignancy, tumor dedifferentiation and angiogenesis

The immunohistochemical distribution of tenascin (TN), fibronectin (FN), and laminin (LN) was investigated in 56 human gliomas (8 astrocytomas, 15 anaplastic astrocytomas, and 33 glioblastomas) with regards to the histological degree of malignancy and the degree of tumor cell differentiation evaluated by the staining of glial fibrillary acidic protein (GFAP). In 8 anaplastic astrocytomas and 28 glioblastomas, TN was predominantly immunolocalized in the basement membrane zone of the proliferating tumor vessels; sections of all astrocytomas were negative for TN staining. FN was localized in the basement membrane zone of the vessels in all astrocytomas, 12 anaplastic astrocytomas, and 22 glioblastomas. In 7 anaplastic astrocytomas and 19 glioblastomas, both TN and FN were expressed to various degrees in the tumor vessels. However, most of the TN-positive vessels did not express FN, and most of the FN-positive vessels were negative for TN staining. Furthermore, in 6 anaplastic astrocytomas and 12 glioblastomas, either TN or FN, but not both, were expressed in any area on serial sections. Most of the tumor cells around TN-positive, FN-negative tumor vessels did not express GFAP. On the other hand, GFAP was present in most tumor cells around TN-negative, FN-positive vessels. LN was detected in all vascular and pial-glial basement membrane zone of the tissues examined. These findings indicate that the degree of histological malignancy and the degree of cell dedifferentiation of human gliomas correlate well with the expression of TN, but are inversely correlated with the expression of FN.(ABSTRACT TRUNCATED AT 250 WORDS)

Okadaic acid induces down-modulation and shedding of tumor necrosis factor receptors. Comparison with another tumor promoter, phorbol ester

Protein kinase C modulates the receptor for tumor necrosis factor (TNF) in wide variety of different cell types. However, there is no information about the role of phosphatases in the regulation of the TNF receptor. In this report, we investigated the effect of okadaic acid, an inhibitor of serine/threonine phosphatases, on TNF receptors in U-937 cells, a human histiocytic lymphoma cell line. In our study okadaic acid induced a dose- and time-dependent down-modulation of TNF receptors. On exposure of cells to 0.5 microM okadaic acid for 60 min at 37 degrees C, a complete down-regulation of the receptors was observed, but no modulation occurred at 4 degrees C. Scatchard analysis of the binding data on U-937 cells revealed that okadaic acid caused a decrease in the high affinity cell surface receptor number without a significant change in the affinity constant. The down-regulation of the TNF receptor by okadaic acid was not specific to U-937 cells, as it was also observed with several other cell types. Okadaic acid had no significant effect on the internalization of the receptor, but it did induce a shedding of the TNF receptor from its cell surface. On exposure of cells to okadaic acid, a dose- and time-dependent increase in the 40-kDa polypeptide was detected in the medium with anti-p80 antibodies by Western blot analysis. The secreted product was also found to bind TNF. The mechanism by which okadaic acid down-modulates the TNF receptor appears to be quite different from that of phorbol ester. First, okadaic acid synergistically potentiated the effect of phorbol ester. Second, the phorbol ester-mediated down-modulation could be blocked by H-7 and staurosporine, well known protein kinase C inhibitors, but these inhibitors had no effect on okadaic acid-mediated response. Third, phorbol ester-mediated down-modulation of the TNF receptor was reversible after removal of the agent, but the response mediated through okadaic acid was irreversible. Fourth, the TNF receptor was down-regulated by okadaic acid but not by phorbol ester in cells depleted of protein kinase C. Thus, overall, our results demonstrate that serine/threonine phosphatases can down-modulate and induce shedding of TNF receptors by a mechanism distinct from that of protein kinase C.

Effect of Pinellia ternata tuber on the efferent activity of the gastric vagus nerve in the rat

Effect of intraduodenal infusion with the hot aqueous extract of Pinellia ternata tuber on the efferent discharges in the gastric branch of the vagus nerve was observed in the anesthetized rat. The infusion of the extract in doses of 2-15O mg per animal (c.a. 300 g, b.wt.) resulted in a dose-related increase in efferent activity of the vagal gastric nerve. The enhancement of the nerve activity following administration of 150 mg of this substance lasted longer than 90 min. It was observed that the suppressive effect on vagal gastric activity due to apomorphine and copper sulfate was antagonized by prior administration of the extract. From these observations it is suggested that Pinellia tuber acts as a facilitatory agent on gastric function.

Pharmacological actions of "kyushin," a drug containing toad venom (3): Effects on experimentally induced arrhythmia

The pharmacological effects of the toad venom-containing drug "kyushin" on aconitine- and thyroxine-induced arrhythmia in guinea pigs, on the conduction system in Langendorff preparations of rabbit hearts and on the autonomic nervous system in cats were studied. "kyushin" significantly inhibited the aconitine-induced arrhythmia after intraduodenal administration (i.d.) with 80 mg/kg, and the thyroxine-induced arrhythmia with 40 mg/kg i.d. Although "kyushin" itself did not affect the conduction system with 30 mg/ml of the maximal concentration being able to be prepared, bufalin and cinobufagin as constituents of toad venom produced inhibition with 0.3 mg/ml and 1 mg/ml, respectively. The decrease in heart rate induced by electrical stimulation to the parasympathetic nerve (vagus nerve) was potentiated by "kyushin" at 30 mg/kg i.d. The anti-arrhythmic effects of "kyushin" may be attributable to both possible inhibitory effect on the conduction system and potentiating effect on the parasympathetic nervous system.

Pharmacological actions of "kyushin," a drug containing toad venom(2): effects on urinary volume and electrolyte excretion

A study was conducted on the pharmacological actions of the toad venom-containing drug "Kyushin" (KY-2 and KY-R) on urinary volume and electrolytes excretion, regional blood flow, renal artery blood flow and carrageenin-induced hind-paw edema. In rabbits, KY-2 and KY-R significantly increased urinary volume after intravenous administration of 8 mg/kg. In guinea pigs, KY-2 and KY-R produced a significant increase in urinary volume after intraduodenal administration (i.d.) of 80 mg/kg. In guinea pigs treated with propranolol, KY-2 at 20 and 40 mg/kg p.o. and KY-R at 40 mg/kg p.o. increased urinary volume. At 40 mg/kg i.d. both KY-2 and KY-R produced an increase in regional blood flow, as determined by the hydrogen gas clearance method, of the brain areas including the amygdaloid nucleus, but did not affect regional blood flow in liver, kidney and skeletal muscle, or renal artery blood flow. In rats, carrageenin-induced hind-paw edema was inhibited by KY-2 or KY-R at 600 mg/kg p.o.

Down-modulation of cell surface expression of p80 form of the tumor necrosis factor receptor by human immunodeficiency virus-1 tat gene

Tumor necrosis factor-alpha (TNF-alpha) induces the expression of human immunodeficiency virus type-1 (HIV-1) in vitro in chronically infected cells of T and monocytic origin. The tat protein from the HIV-1 virus has been shown to be essential for HIV replication and in the immunosuppression associated with the virus infection. Previous studies in our laboratory have shown that HIV-1 tat gene induces TNF-beta (lymphotoxin) in human B-lymphoblastoid cells (Sastry et al., 1990, J. Biol. Chem. 265, 20091-20093). In an attempt to characterize further the relationship between the host and HIV-1, we investigated the effect of the functional HIV-1 tat gene on the expression of TNF receptors in a human B lymphoblastoid cell line (Raji). We report here that Raji cells transfected with HIV-1 tat gene express fewer cell surface TNF receptors than control cells. At least a 5-fold decrease in the receptor number without any significant change in receptor affinity was observed. The decrease in TNF receptors in tat-transfected Raji cells (Raji-tat cells) was found not to be due to receptor occupancy by the autocrine production of TNF-beta. The decrease in the cell surface expression of TNF receptors in Raji-tat cells was also found to be not due to a decrease in the gene expression of the receptor. The kinetics, amount of TNF binding and its internalization were temperature dependent, and it was different in Raji-tat cells than in the control cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of daily physical activity on insulin action in the elderly

The effects of daily physical activity on peripheral insulin action were investigated in aged individuals. Glucose infusion rates (GIR) during the euglycemic insulin clamp procedure in aged bedridden, aged controls, and aged athletes were compared with those in young controls and young athletes at insulin infusion rates of 40 and 400 mU.m-2.min-1 to estimate insulin action at physiological and maximal insulin concentrations, respectively. At both insulin infusion rates, GIR was significantly higher in aged athletes and significantly lower in aged bedridden subjects than in aged controls. Although there was no statistical difference in GIR at 400 mU.m-2 x min-1 between young athletes and young controls, GIR at 40 mU.m-2 x min-1 was higher in young athletes than in young controls. Comparison of the aged and young groups showed that although GIR at 400 mU.m-2 x min-1 was significantly lower in aged controls than in young controls, there was no significant difference between the aged athletes and the young athletes. We conclude that insulin responsiveness (insulin action at the postreceptor binding site) may decrease with the aging process and may be further affected by physical inactivity. Although physical training may improve insulin responsiveness in aged individuals up to levels similar to those in young athletes, physical training in young individuals may improve only insulin sensitivity.

Inherited WT1 mutation in Denys-Drash syndrome

Patients with the Denys-Drash syndrome (Wilms' tumor, genital anomalies, and nephropathy) have been demonstrated to carry de novo constitutional mutations in WT1, the Wilms' tumor gene at chromosome 11p13. We report three new cases, two carrying a previously described WT1 exon 9 mutation and one with a novel WT1 exon 8 mutation. However, unlike patients in previous reports, one of our three patients inherited the affected allele from his phenotypically unaffected father. This observation indicates that the WT1 exon 9 mutation affecting 394Arg demonstrated in over one-half of the patients with the Denys-Drash syndrome may exhibit incomplete penetrance. Consequently, familial studies in patients affected by this syndrome are recommended.

Effects of the new thromboxane A2 antagonist vapiprost on isolated canine blood vessels

Effects of the new thromboxane A2 antagonist vapiprost (SN-309, GR-32191B, CAS 85505-64-2) on isolated canine blood vessels were investigated. U46619 ((15S)-hydroxy-11a, 9a-(epoxymethano) prosta-5Z, 13E-dienoic acid) 10(-10)-10(-6) mol/l, a thromboxane A2 analogue, produced concentration-dependent contractions of oblong or ring preparations isolated from basilar, coronary, mesenteric and femoral arteries. Vapiprost 10(-8) and 10(-7) mol/l significantly and concentration-dependently shifted the concentration-contraction curves for U46619 of these arteries to the right. The pA2 values were 8.80 +/- 0.09 in basilar arteries, 8.67 +/- 0.12 in coronary arteries, 8.86 +/- 0.05 in mesenteric arteries and 9.01 +/- 0.07 in femoral arteries. On the other hand, oblong or ring preparations of basilar, coronary, mesenteric and femoral arteries showed sustained contractile responses to KCl 3 x 10(-2) mol/l, U46619 10(-7) mol/l or prostaglandin (PG) F2 alpha 10(-5) mol/l. Norepinephrine (NE) 3 x 10(-5) mol/l also produced sustained contractions in mesenteric and femoral arterial preparations, but not in basilar and coronary arterial preparations. Vapiprost 10(-10)-3 x 10(-6) mol/l relaxed these four arterial preparations constricted with U46619 10(-7) mol/l and PGF 2 alpha 10(-5) mol/l in a concentration-dependent fashion, but hardly affected them constricted with KCl 3 x 10(-2) mol/l. NE 3 x 10(-5) mol/l-induced contractures of mesenteric and femoral arterial preparations were not influenced by any concentrations of vapiprost. Results indicate that vapiprost has an antagonistic action on a so-called TP-receptor and/or a vasoconstrictive prostaglandin(s)-receptor and thus produces vasorelaxation.

Modulation of two forms of tumor necrosis factor receptors and their cellular response by soluble receptors and their monoclonal antibodies

Recently, two different receptors for human tumor necrosis factor (TNF) with molecular masses of 60 kDa (p60) and 80 kDa (p80) have been identified. In this report, we investigated the effect of the soluble forms of these receptors and monoclonal antibodies against them on ligand interaction, receptor down-regulation, and mediation of cellular response in U-937 cells. Our results indicate that p60 and p80 constitute 20-30 and 60-80% of the total TNF-binding sites on U-937 cells, respectively. However, by cross-linking, only the p80 form of the receptor could be detected. In contrast to unlabeled TNF, the anti-p60 and anti-p80 antibodies together only partially inhibited ligand binding, and this inhibition was not additive. Lack of additive inhibition of binding was found to be not due to stereo-chemical hindrance. TNF binding to cells can be completely displaced by soluble forms of either the p60 or p80 receptor. However, 100-fold more of the p80 than the p60 form of the soluble receptor is needed for equivalent displacement. Under optimum conditions, TNF and the anti-p80 and anti-p60 antibodies down-regulated 30, 80, and 20% of the TNF receptors, respectively. The anti-p60 and anti-p80 antibodies down-regulated not only their own receptors, but also reciprocal receptors, suggesting a cross-communication between the p60 and p80 forms of the TNF receptor. In spite of inhibiting as much as 80% of TNF binding, none of the receptor antibodies significantly inhibited the cytotoxic response to TNF in U-937 cells. Soluble forms of both receptors, however, completely abrogated the cellular response to TNF. Thus, overall, our results indicate that the antibodies against both receptors together inhibit the majority of the receptor-ligand interaction without any significant effect on the biological response to TNF.

Correlation of contractile dysfunction and abnormal tissue energy metabolism during hypoperfusion with norepinephrine in isolated rat hearts: differences between normal and diabetic hearts

The relationship of myocardial high-energy phosphate depletion and lactate accumulation with contractile dysfunctions was investigated in streptozotocin-diabetic (DM) and normal rat hearts. The isolated hearts were perfused with 10(-6) M norepinephrine (NE) at various low-flow rates (0.4-6 ml/min/g heart wt) for 1 h. Left ventricular pressure (LVP) and contractile force (CF) were monitored, through a water-filled balloon in LV and through a hook attached to the apex, respectively. In DM hearts resting CF (diastolic tension) increased, when the perfusion flow rate was reduced below 6 ml and reached a maximum at a flow rate of less than 3 ml. The large increase in LV stiffness correlated with an elevation in diastolic LVP. In normal hearts these parameters were elevated at a flow rate below 1 ml. A flow-dependent decrease in developed CF was more prominent in DM than in normal hearts, while developed LVP and perfusion pressure were slightly higher in DM hearts with a marked increase in the LV stiffness. A flow-dependent decrease in high-energy phosphates and increases in inorganic phosphate and lactate were more prominent in the inner than in the outer layer of LV free wall in both groups. The change of ATP in the inner layer was greater, while increases of lactate in both layers were smaller in DM hearts. Changes in mechanical parameters correlated well with the ATP decrease and lactate increase in the inner layer in both groups. The correlation curves, however, were not coincidental: at the same low ATP and high lactate level, the LV stiffness was higher in DM hearts. Results indicate that DM hearts are more susceptible to flow-reduction with NE and depletion of total ATP in their tissue, and easily suffer from increased LV stiffness. This cannot be explained by the rate of decrease in total ATP and lactate accumulation alone.

Reduced nicotinamide adenine dinucleotide oxidase involvement in defense against oxygen toxicity of Streptococcus mutans

The growth inhibition of the Streptococcus mutans group, including Streptococcus mutans, Streptococcus cricetus, Streptococcus rattus and Streptococcus sobrinus, on glucose by oxygen and the properties of reduced nicotinamide adenine dinucleotide (NADH) oxidase induced by oxygen, using a representative oxygen-tolerant strain, were examined. The growth response to oxygen varied among strains and correlated with the level of NADH oxidase activity in the cell extract. The induced synthesis of NADH oxidase as well as superoxide dismutase was affected by oxygen tension and energy sources. The induced NADH oxidase involved at least two types, major H2O-forming NADH oxidase and minor H2O2-forming NADH oxidase activity. In the presence of a scavenger of H2O2, pyruvate, the growth inhibition by oxygen in an oxygen-sensitive strain (GS5) was protected but not in another oxygen-sensitive strain (MT8148). The high level of induced H2O-forming NADH oxidase activity protected against oxygen toxicity.

A comparative study on tissue distribution and metabolic adaptation of IMP-GMP 5'-nucleotidase

1. Activity of a cytoplasmic 5'-nucleotidase which preferentially hydrolyzes IMP and GMP (IMP-GMP 5'-nucleotidase) was determined by a specific immunochemical method in two species of birds and two species of mammals. 2. The activity was markedly high in avian liver, and it increased two-fold in response to a high protein diet in chicken liver. 3. In mammals, the activity was high in testis and spleen. In the rat, the activities in liver, kidney and heart extracts increased by about 30% in response to the high protein diet, while they increased three-fold in regenerating liver. 4. Low activities were detected in skeletal muscles and in erythrocytes of all the species studied.

Activation of human monocytes by interleukin-2 and various cytokines

We previously reported that human macrophages cultured with IL-2 for a long period (lymphokine-activated macrophages, LAMs) showed high tumoricidal activity against human and murine leukemic cell lines through a different mechanism from lymphokine-activated killer (LAK) cells. In this report, we investigated the effects of various cytokines on the tumoricidal activity of IL-2-induced LAMs against HeLa cells. CSF-1 and IL-1 were found to enhance the tumoricidal activity of LAM in a dose-dependent manner, whereas IFN-gamma and TNF had inhibitory effects. CSF-1 in combination with a low dose of IL-2 synergistically induced LAMs with highly tumoricidal activity. We also found that monocytes from some donors that did not respond to IL-2 were differentiated to tumoricidal macrophages by treatment with a combination of CSF-1 and IL-2. Furthermore, IL-2-induced LAMs were found to produce cytotoxic factors in the culture medium when they were cocultured with tumor cells, and the cytotoxic activity in the culture supernatant of LAMs was also increased by the incubation of LAMs with CSF-1. The cytotoxicity of the supernatants from macrophages with different tumoricidal activity correlated with their cell-mediated cytotoxicity. It is suggested from these results that the cytotoxicity of LAMs is regulated by CSF-1, IL-1, IFN-gamma, and TNF, and that the production of cytotoxic molecules is involved in cell-mediated killing by LAMs.

Exercise training increases glucose transporter content in skeletal muscles more efficiently from aged obese rats than young lean rats

Glucose uptake in rat skeletal muscles decreases with age and obesity, but increases with chronic exercise training. The purpose of our study was to determine whether the GLUT4 content in several skeletal muscles from 1-mo-old young, lean rats and 12-mo-old aged, obese rats alters with exercise training. For exercise, a treadmill run of approximately 1 km/day was made for 4 wk by both groups of rats. The concentration of GLUT4 per protein in membrane fraction from several skeletal muscles was measured by immunoblotting. The amount of GLUT4 in the gastrocnemius and white quadriceps from aged rats slightly but significantly decreased to 73% and 78% of that from young rats, respectively. However, no significant difference in GLUT4 amount in the soleus, plantaris, and red quadriceps was observed between young and aged rats. The exercise training resulted in a larger increase in the amount of GLUT4 in each muscle from aged rats than in muscles from young rats. In aged rats, GLUT4 amount increased significantly with exercise training by 30, 33, 41, and 27% in the soleus, plantaris, gastrocnemius, and red quadriceps, respectively, compared with the sedentary controls. However, in young rats, exercise-induced increase of GLUT4 amount was significant only in the plantaris, and the increase was 17%. In exercised aged, obese rats, decreases of body weight, plasma triglyceride levels, and plasma free fatty acid were also observed.(ABSTRACT TRUNCATED AT 250 WORDS)