Hematopoietic stem cells found in lineage-positive subsets in the bone marrow of 5-fluorouracil-treated mice

It is known that treatment of mice with 5-fluorouracil (5-FU, 150 mg/kg) confers radioprotection. To investigate this effect, we performed bone marrow transplantation (BMT) using C57BL/6-Ly5 congenic mice treated with 5-FU five days prior to experiments. The mononuclear cells (MNC) in 5-FU-treated bone marrow (BM) were 10 times more radioprotective than those in untreated BM. Moreover, the number of BM MNC expressing c-kit on their surface from 5-FU-treated mice was markedly decreased relative to those from untreated controls. These results showed that the surface characteristics of cells that contributed to this radio-protective effect differ from those of stem cells as reported recently. BM MNC of mice treated with 5-FU were separated on the basis of expression of the lineage-specific antigens (Lin), c-kit, and Ly6A/E. When injected into lethally irradiated mice, 1,000 Lin+ and Lin-c-kit+Ly6A/E+ cells showed radioprotective effects such that 100% and 60% survived, respectively. Flow cytometric analysis 165 days after BMT showed that 88.8% and 65.1% of peripheral blood (PB) in mice transplanted with Lin+ and Lin-c-kit+Ly6A/E+ was derived from donor mice, respectively. After six months, donor-derived Lin-c-kit+Ly6A/E+ cells which showed radioprotective effects on a secondary irradiated host were detected from mice transplanted with Lin+ cells from 5-FU-treated mice. Taken together, these findings demonstrated that stem cells expressing Lin+ present in the BM of mice treated with 5-FU other than Lin-c-kit+Ly6A/E+ cells and these Lin+ cells play an important role in the recovery of myeloablative mice.

[Anterior nerve roots enhancement on MRI in a case of Guillain-Barré syndrome]

A 4-year-old girl with Guillain-Barré syndrome (GBS) showed the abnormal enhancement on MRI in the anterior nerve roots corresponding to the region of her muscle weakness on the 26th day of illness. The enhancement on MRI almost disappeared on the 89th day of illness, when her symptoms had more improved. We think that enhanced spinal MRI is useful to reveal the involved nerve roots and the degree of the illness in GBS.

A case of iatrogenic growth retardation induced by a corticosteroid-containing anti-allergic drug

A nine-year old boy developed reduced growth velocity at the age of seven. The peak plasma growth hormone (GH) response to 3,4-dihydroxyphenylalanine, GH-releasing factor and insulin was 10.2, 8.1 and 7.6 micrograms/l, respectively, suggesting that the GH reserve was slightly reduced. Serum cortisol was undetectable and urinary excretion of 17-hydroxycorticosteroid was low (0.22-0.31 mg/day), but there were no physical or biochemical signs of adrenocortical insufficiency. He had taken an anti-allergic drug containing 0.25 mg of betamethasone and 2 mg of d-chlorpheniramine maleate per tablet for about 2 years to treat allergic rhinitis. Catch-up growth occurred when this drug was stopped. The present case suggests that daily administration of 0.25 mg of betamethasone can induce growth retardation and that ingestion of corticosteroid-containing preparations needs to be excluded in children who develop short stature without other symptoms.

Homing of 51Cr-labeled human peripheral lymphocytes to Graves' thyroid tissue xenografted into SCID mice

We have recently described a NUDE/SCID mouse model that has been useful for the study of human thyroid autoimmunity in in vivo conditions. The reappearance of lymphocytic infiltration in Graves' thyroid tissue and a humoral response in SCID mice (rexenografted with normalized thyroid tissues from NUDE mice) was detected only if autologous Graves' human peripheral lymphocytes (PBMC) were engrafted into the same animals. Therefore it was presumed that some autoreactive PBMC directed themselves to the thyroid. However, there was previously no direct evidence regarding the trafficking of the engrafted PBMC to the target tissue. To elucidate this point we have studied the migration of 51Cr-labeled PBMC in SCID mice. Human thyroid tissue from six Graves' disease (GD) patients and six patients with nontoxic nodular goiter were initially xenografted into NUDE mice for 8 weeks. The same tissues were retrieved and rexenografted into several "virgin" SCID mice, i.e., no previous xenografts. Autologous PBMC were isolated from blood of the same patients obtained at the time of the tissue rexenograftment and labeled with radioactive 51Cr. Twenty million labeled PBMC were engrafted into each SCID mouse. The distribution of labeled lymphocytes into mouse organs and trafficking into Graves' and normal xenografts was measured. A significant amount of radioactivity in Graves' xenografts was detected after 1 week with the peak of radioactivity at 2-3 weeks. This radioactivity was significantly higher than radioactivity in surrounding tissues (skin, muscle). In contrast, homing of autologous lymphocytes into normal paranodular thyroid tissue was very minimal; the radioactivity of GD thyroid xenografts with engrafted autologous lymphocytes was significantly higher than that of normal tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of monoclonal antibody against CD45RB on peripheral blood mononuclear cell proliferation and on HLA-DR and adhesion molecule expression on thyrocytes of patients with autoimmune thyroid disease

To evaluate the role of CD45 (especially that of the ectodomain region B) on immunocyte-thyrocyte signaling in patients with autoimmune thyroid disease (AITD), we have examined the in vitro and in vivo effects of a monoclonal antibody (mAb) against with CD45RB, termed MT3. MT3 was added to cultured peripheral blood mononuclear cells (PBMC) from patients with AITD and was additionally injected into severe combined immunodeficient (SCID) mice to which Graves' thyroid cells and intrathyroidal lymphocytes were engrafted. MT3 stimulated proliferation of PBMC when cultured for 2 to 3 days in patients with Hashimoto's thyroiditis (HT) and Graves' disease (GD) and in normal controls (NC). However, when cultured for 7 days, the stimulation index [SI: counts per minute (cpm) with mAb/cpm without mAb] was lowered by MT3 in NC and GD patients. However, the mean SI was not lowered in patients with HT. In SCID mice, the concentrations of human immunoglobulin G, antithyroglobulin and antithyroperoxidase antibodies in sera were not significantly changed by injecting MT3. The expression of human leukocyte antigen (HLA)-DR and intercellular adhesion molecule (ICAM)-1 on engrafted human thyrocytes decreased after the tissues were engrafted into the control mice to which vehicle alone was injected. However, in the mice injected with MT3, HLA-DR and ICAM-1 expression remained high or up-regulated by the injection.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of the novel calcium antagonist AE0047 on responses of isolated dog blood vessels to vasoconstricting agents and to nerve stimulation]

The effect of AE0047 on contractile responses to high K+ and agonists and to perivascular nerve stimulation was investigated using isolated dog cerebral, coronary and mesenteric arteries and mesenteric veins. AE0047 inhibited concentration-dependent contractions induced by KCl, norepinephrine, prostaglandin (PG) F2 alpha and serotonin. The inhibition of contractions caused by PGF2 alpha and serotonin was greater in cerebral arteries than in mesenteric arteries. The inhibitory effect of AE0047 on norepinephrine-induced mesenteric arterial contraction persisted for 24 hr or longer even though the strips were repeatedly washed. Greater inhibition was obtained in the arteries contracted with K+ than in those contracted with agonists. AE0047 reduced Ca(2+)-induced contraction in K(+)-depolarized mesenteric artery strips to a greater extent than those in PGF2 alpha-stimulated strips. The relaxation induced by transmural electrical stimulation in coronary arteries treated with phenotolamine was reduced by AE0047, whereas the norepinephrine-induced relaxation was unaffected. In cerebral arteries treated with superoxide dismutase, AE0047 reduced nicotine-induced relaxation but not NO-induced relaxation. These findings suggest that AE0047 selectively inhibits vasocontractions via voltage-dependent Ca channels and preferentially inhibits cerebroarterial contraction, these actions being long-lasting. AE0047 appears to reduce the release of neurotransmitter from adrenergic and nitroxidergic nerve terminals in blood vessels.

Protective effects of a glucocorticoid on downregulation of pulmonary beta 2-adrenergic receptors in vivo

We investigated the in vivo effects of a glucocorticoid on beta-agonist-induced downregulation of beta 1- and beta 2-adrenergic receptors (determined by [125I]iodocyanopindolol binding), mRNA expression (assessed by Northern blotting), and gene transcription (using nuclear run-on assays) in rat lung. Dexamethasone (Dex) (0.2 mg/kg/d, days 1-8) increased beta 1- and beta 2-receptor numbers by 70 and 69% above control, respectively, but did not change their mRNA expression. Isoproterenol (Iso) (0.96 mg/kg/d, days 2-8) decreased beta 1- and beta 2-receptor numbers by 48 and 51%, respectively, and also reduced mRNA expression by 69 and 57%, respectively. The combination of Dex and Iso resulted in no net change in beta 2-receptor number and its mRNA expression, although there was a significant reduction in beta 1-receptor number and mRNA expression. The mapping of beta 1- and beta 2-receptors by receptor autoradiography confirmed these findings over alveoli, epithelium, endothelium, and airway and vascular smooth muscle. We also measured the activation of the transcription factor, cyclic AMP response element binding protein (CREB) using an electrophoretic mobility shift assay. CREB-like DNA-binding activity was decreased after Iso treatment but this decrease was prevented after treatment with Dex. Nuclear run-on assays revealed that the transcription rate of the beta 1-receptor gene did not alter after Dex treatment, but was reduced after Iso treatment. The transcription rate of the beta 2-receptor gene was increased after Dex treatment by approximately twofold, but there was no change after Iso treatment. We conclude that glucocorticoids can prevent homologous downregulation of beta 2-receptor number and mRNA expression at the transcriptional level without affecting beta 1-receptors and that the transcription factor CREB may be involved in this phenomenon. Such an effect may have clinical implications for preventing the development of tolerance to beta 2-agonists in asthmatic patients treated with beta-agonist bronchodilators.

Thyroid stimulating antibody in sera of Graves' ophthalmopathy patients as a possible marker for predicting the efficacy of methylprednisolone pulse therapy

Nine patients with Graves' ophthalmopathy (GO) were treated with intravenous methylprednisolone pulse therapy and followed up by ophthalmological assessment, magnetic resonance imaging, and thyroid-associated autoantibody (thyroid stimulating antibody (TSAb), TSH binding inhibitor immunoglobulins (TBII), and anti-eye muscle antibody (EMAb)). Ophthalmological assessment was performed by the ophthalmopathy index (OI) which was made on the basis of the system recommended by the American Thyroid Association Committee. EMAb was expressed as the ratio of density of the 64 kDa band of eye muscle membrane to that of 92 kDa non-specific band found with all normal sera when assessed by western blotting. Five patients with mild ophthalmopathy (OI < 4) did not show progressive improvement in OI. Three of 4 patients with severe eye disease (OI > 4) showed a progressive and distinct improvement in OI. These 3 patients had high TSAb levels before methylprednisolone pulse therapy. One patient with severe ophthalmopathy did not respond to this pulse therapy; this patient's TSAb was negative. A significant positive correlation was observed between the activity of TSAb before treatment and the improvement in OI (delta OI) (r = 0.86, P < 0.01, n = 9). The relationship between delta OI and EMAb did not reach significance. These results suggest that TSAb in sera of GO patients can be a useful marker for predicting the efficacy of methylprednisolone pulse therapy.

Galactosylated proteins are recognized by the liver according to the surface density of galactose moieties

The recognition of 111In-labeled galactosylated superoxide dismutase (Gal-SOD) and galactosylated bovine serum albumin (Gal-BSA) by the liver was investigated in mice after intravenous injection. 111In-labeled galactosylated proteins were recovered in the liver by amounts that were highly dependent on the degree of galactose modification and the administered dose. The distribution patterns were analyzed based on a physiological pharmacokinetic model including an uptake process with Michaelis-Menten kinetics in the liver and hepatic plasma flow. The Michaelis constant of hepatic uptake of 111In-Gal-SOD was observed to inversely correlate with the number of galactose residues, without a significant change in maximum rate of uptake or extrahepatic clearance. This relation could be applied to 111In-Gal-BSA and other galactosylated proteins by using the surface density of galactose residues as a degree of modification, suggesting galactose density controls ligand recognition by the asialoglycoprotein receptor. The analysis also indicated that increasing galactose density higher than 1.0 x 10(-3) molecules/A2 did not affect the distribution of galactosylated proteins due to limitation by the hepatic plasma flow rate. In conclusion, efficient delivery of proteins modified with galactose to the liver will be achieved by controlling both the galactose density on the protein surface and the administered dose.

[Low-dose cytarabine ocfosfate therapy in an elderly acute myelogenous leukemia]

A 71-year-old man was admitted for severe anemia. Bone marrow puncture revealed 48% of blast cells. A diagnosis of acute myelogenous leukemia (AML-M 4) was made. As the patient was old, we administered 300mg of cytarabine ocfosfate (SPAC) for 21 days. Blast cells in bone marrow decreased 5.6%, and SPAC was considered effective. We treated him with the same dose of SPAC for 14 days after a 21-day interval from the end of the first treatment. Although leukemic cells were still seen in bone marrow after two treatments, we considered him in partial remission, and he was discharged. After discharge, the hematological findings remain almost normal with intermittent treatment of 150 mg of SPAC for over one year. Thus, cytarabine ocfosfate might be useful in elderly AML patients.

Bioactivity of thyrotropin (TSH) in patients with central hypothyroidism: comparison between in vivo 3,5,3'-triiodothyronine response to TSH and in vitro bioactivity of TSH

To investigate the cause(s) of central hypothyroidism with normal or elevated TSH concentrations, we evaluated the bioactivity of serum TSH as well as pituitary and thyroid function. Seven hypothyroid patients had documented deficiencies of anterior pituitary hormones other than TSH. Basal TSH concentrations ranged from 2.2-14.8 microU/mL. Six patients had low T4 and free T4 concentrations; the remaining patient had a low free T4 and a low normal T4 level with an elevated TSH concentration of 14.4 microU/mL. The mean increment in TSH 30, 60, and 90 min after TRH administration (mean delta TSH) in these patients was 13.5 +/- 9.1 microU/mL (mean +/- SD), which was not significantly different from the value in controls (9.2 +/- 3.5 microU/mL). However, the ratio of the T3 increment at 120 min (delta T3) to mean delta TSH (delta T3/mean delta TSH) in patients was 53.9 +/- 29.3 ng/microU, significantly lower than the control value of 239.5 +/- 97.5 ng/microU (P < 0.01), suggesting that the thyroid response to endogenous TSH was blunted. The serum T4 concentration correlated with the mean delta TSH in these patients (r = 0.78; P < 0.05), suggesting that hypothyroidism is dependent on conserved pituitary function. The mean bioactivity to immunoreactivity ratio of basal TSH in patients was 0.97 +/- 0.27 and was not significantly different from the normal value of 1.05 +/- 0.22. One of the two patients with high basal TSH (> 10 microU/mL) had a ratio of 0.59, which is just below the mean +/- SD of normal subjects (0.61), suggesting that most patients had normal TSH bioactivity in vitro. Our findings suggest that in vivo bioactivity of TSH is decreased because of a pituitary disorder, but in vitro bioactivity of TSH is variable in patients with central hypothyroidism.

The effects of dietary fiber from Lagenaria scineraria (yugao-melon) on colonic carcinogenesis in mice

BACKGROUND

The increasing trend of colon cancer in Japan is attributed to changes in dietary habits, that is, increased amounts of fat and decreased amounts of fiber in the diet. The effects of Japanese dietary fiber from Lagenaria scineraria (yugao-melon) on colonic carcinogenesis in mice were examined.

METHODS

Eighteen ICR mice in each group were fed with either a basal diet or a diet containing 5%, 10%, or 20% of yugao powder for 35 weeks. All the mice received a weekly intraperitoneal injection of 1,2-dimethylhydrazine (DMH), 10 mg/kg body weight for 10 weeks. The effects of yugao powder on the mucosal and luminal variables involved in colonic carcinogenesis were then compared with those of wheat bran in the mice without any carcinogen treatment.

RESULTS

The incidence of colon tumors (adenocarcinomas) was lower in the yugao powder diet groups than in the basal diet group at week 35 (24% vs. 50%, P < 0.05). The bile acid concentration in the colon was reduced in all the fiber diet groups except for the 5% yugao powder diet group. The colonic luminal pH acidified as yugao powder contents also increased in the yugao powder diet groups. The findings on the colonic short chain fatty acids, microflora, and mucosal fatty acids and ornithine decarboxylase activity were all inconsistent with a tendency to either develop or to inhibit carcinogenesis in both the fiber diet groups.

CONCLUSIONS

Dietary fiber from yugao-melon suppressed DMH-induced colonic carcinogenesis in mice by lowering the bile acid concentration and pH in the colon. The results of the luminal and mucosal variables examined also suggested that the mechanisms of action of yugao powder against colonic carcinogenesis differed from those of wheat brain.

Decreased expression of protein phosphatase type 2A in HL-60 variant (HL-60RAr) cells resistant to induction of cell differentiation by all-trans retinoic acid

To evaluate the molecular basis for susceptibility of the cell differentiation induced by all-trans retinoic acid (ATRA), we examined biochemical activities and expression of protein phosphatases type 1 (PP1) and type 2A (PP2A) from HL-60 cells that are susceptible to differentiation induced by ATRA and HL-60RAr cells, HL-60 variant cells that are resistant to such induction. One nM of calyculin-A (CAL-A) achieved the enhancement of granulocytic differentiation in ATRA-treated HL-60 (1 microM) cells. ATRA exerted no differential action in HL-60RAr cells, but when used in combination with CAL-A, the differential activity was partly resumed at functional and phenotypic levels without change in morphology. The phosphatase activity in the cytosol from HL-60RAr cells was 50% of that from parental HL-60 cells, but the enzyme activities in either membrane or nuclear fractions showed similar values. The decreased phosphatase activity in the cytosol of HL-60RAr cells was mainly due to the decreased expression of the PP2A catalytic subunit. This low level of PP2A protein was reflected at a relative deficiency in expression of the PP2A beta gene in HL-60RAr cells. The exposure to 1 microM ATRA resulted in downregulation of PP2A catalytic subunit protein in HL-60 cells, but ATRA did not affect PP2A expression in HL60RAr cells. Both cell lines expressed the proteins of each PP1 catalytic subunit isozyme (i.e., PP1 alpha, PP1 gamma, and PP1 delta) at comparable levels. ATRA treatment had no effect on the levels of PP1 isozymes. Our results show a correlation between the extent of PP2A expression and the response of HL-60 and HL-60RAr cells to the differentiative effects of ATRA.

Carbachol and cholecystokinin enhance accumulation of nicotine in rat pancreatic acinar cells

Nicotine is a possible risk factor for chronic pancreatitis and pancreatic cancer. To study the loci where nicotine might exert its effect, we examined interactions between nicotine and rat pancreatic acini. When pancreatic acini were incubated with [3H]nicotine, [3H]nicotine levels in pancreatic acini were increased in time-and dose-dependent manners, and the t1/2 for dissociation of [3H]nicotine was 63.8 min. At 4 degrees C, the association of [3H]nicotine was 33% of the association at 37 degrees C. Unlabeled nicotine had no significant effect on the accumulation of [3H]nicotine. In addition, surface-bound [3H]nicotine was not detected when acini were washed in a low-pH solution or when they were trypsinized. These results suggest that the accumulation of nicotine may be a biological phenomenon and that [3H]nicotine does not bind to surface receptors of acinar cells, but accumulates intracellularly. The addition of verapamil (0.1 mM) or 12-O-tetradecanoylphorbol-13-acetate (1 microM) had no effect on [3H]nicotine association, while 4-bromo-A23187 (2 microM) or EGTA (10 mM) significantly increased the accumulation of [3H]nicotine. Carbachol and cholecystokinin significantly enhanced the accumulation of [3H]nicotine in a dose-dependent manner. Taken together, the increasing effects of carbachol and cholecystokinin on the accumulation of nicotine may explain, at least in part, the mechanisms involved in the multiplicative effects of the combination of two risk factors, smoking habit and high-fat or high-protein diets, on human pancreatic diseases.

Translocation of protein phosphatase 1 catalytic subunits during 1,25-dihydroxyvitamin D3-induced monocytic differentiation of HL-60 cells

To elucidate the roles of protein phosphatases type 1 (PP1) and type 2A (PP2A) in 1,25-dihydroxy-cholecalciferol [1,25(OH)2D3]-induced differentiation of HL-60 cells into monocytes, we examined the enzyme activity and the protein and gene expressions of PP1 and PP2A in these cells. Calyculin-A augmented the 1,25(OH)2D3-induced differentiation of the cells. Treatment of the cells with 1,25(OH)2D3 led to a decrease in PP1-like activity in the cytosol fraction, with a concomitant increase in the membrane and nuclear PP1-like activity, as determined when protein phosphatase activity was assayed using myosin light chain as substrate in the presence of 5 nM okadaic acid. Western blot analysis with antibodies specific for PP1 catalytic subunit isozymes (PP1 alpha, PP1 gamma, and PP1 delta) showed that all three PP1 isozymes were expressed but were differentially distributed in each cellular fraction. Subcellular redistribution of PP1-like activity during 1,25(OH)2D3-induced differentiation was mainly attributed to PP1 gamma and PP1 alpha proteins. In contrast, the localizations of PP1 delta and PP2A catalytic and regulatory subunits were not significantly affected by 1,25(OH)2D3 treatment. The gene expressions of PP1 alpha and PP1 gamma appeared to be constant during processes of monocytic differentiation. The correlation between phenotypic and functional changes of HL-60 cells on the one hand and subcellular redistribution of PP1-like activity on the other suggest that the translocations of PP1 alpha and PP1 gamma isozymes may contribute to the 1,25(OH)2D3-induced monocytic differentiation of HL-60 cells.

Effect of leukotriene C4D4 antagonist on colonic damage induced by intracolonic administration of trinitrobenzene sulfonic acid in rats

We examined the effects of eicosanoid antagonists on colonic damage induced by trinitrobenzene sulfonic acid (TNB) in a rat inflammatory bowel model. TNB (30 mg) dissolved in 0.25 ml of 50% ethanol, was given intrarectally. The appropriate doses of ONO-1078 (a leukotriene C4D4 antagonist), ONO-4057 (a leukotriene B4 antagonist), and OKY-046 (a thromboxane A2 synthetase inhibitor) were given to obtain the same blood level, either 4 h before (pre-treatment model) or 24 h after (the post-treatment model) the administration of TNB (n = 8 in all groups). Drugs were given once daily for 6 days through a gastric feeding tube. Autopsy was performed on the 7th day. Colonic damage was assessed in terms of colonic damage scores, and myeloperoxidase (MPO) activity and eicosanoid concentrations in colonic tissues were measured. Compared with the group given TNB alone, the colonic damage score was reduced to 10% in the pre-treatment model with ONO-1078, but the score was not reduced in other groups, MPO activity was not changed in any group. The concentration of leukotriene C4 was reduced with ONO-1078 treatment, in both pre- and post-treatment models. These results demonstrated that a leukotriene C4D4 antagonist reduced colonic inflammation; however, its anti-inflammatory effect was limited in this colitis model.

Design for cell-specific targeting of proteins utilizing sugar-recognition mechanism: effect of molecular weight of proteins on targeting efficiency

Hepatic targeting of proteins utilizing the sugar-recognition mechanism was investigated in mice after intravenous injection. Five proteins with different molecular weights, i.e., bovine gamma-globulins (IgG), bovine serum albumin (BSA), recombinant human superoxide dismutase (SOD), soybean trypsin inhibitor (STI), and chicken egg white lysozyme (LZM), were modified with 2-imino-2-methoxyethyl 1-thiogalactoside to obtain galactosylated proteins (Gal-IgG, Gal-BSA, Gal-SOD, Gal-STI, and Gal-LZM). The numbers of galactose residues were 38, 20, 11, 6, and 5 for Gal-IgG, Gal-BSA, Gal-SOD, Gal-STI, and Gal-LZM, respectively. All galactosylated proteins were dose-dependently taken up by the liver and the relative amount accumulated in the liver was decreased with an increase of the administered dose. At low doses (0.05 and 0.1 mg/kg), Gal-IgG, Gal-BSA, and Gal-SOD could be taken up by the liver up to more than 70-80% of dose within 10 min after intravenous injection, but the maximum amounts accumulated in the liver were approximately 40 and 30% of the dose for Gal-STI and Gal-LZM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological and pharmacological properties of highly selective new endothelin converting enzyme inhibitor WS79089B isolated from Streptosporangium roseum No. 79089

WS79089B a highly specific endothelin converting enzyme (ECE) inhibitor has been isolated from the fermentation broth of Streptosporangium roseum No. 79089. WS79089B showed highly selective ECE inhibition activity with IC50 value of 0.14 microM and behaved as a competitive inhibitor of ECE, with Ki values of 8.9 x 10(-8) M. The sodium salt of WS79089B (FR901533) inhibited big endothelin-1 (big ET-1) induced pressor effect in a dose dependent manner when administered to male Sprague-Dawley rats intravenously dosed 2 minutes prior to big ET-1 challenge.

Glucocorticosteroids increase beta 2-adrenergic receptor transcription in human lung

beta 2-Adrenergic receptors (beta 2R) are widely distributed and mediate a wide range of cellular responses in lung. Because glucocorticosteroids increase expression of beta 2R in cell lines, we have investigated the effects of glucocorticoids on the beta 2R mRNA level and the number of beta 2R in human peripheral lung in vitro. Incubation of lung tissues with dexamethasone (Dex) elevated both beta 2R mRNA level (as measured by Northern blot analysis) and beta 2R number (as measured by [125I]iodocyanopindolol binding). The increased accumulation of beta 2R mRNA could be detected at 15 min (1.27 +/- 0.1-fold) and the maximal accumulation occurred at 2 h (2.73 +/- 0.5-fold). The Dex-induced increase in beta 2R mRNA returned to the control level by 17 h. The increase in beta 2R number (1.58 +/- 0.2-fold) was slower, reaching a maximum between 17 and 24 h. Dex increased beta 2R mRNA in a time- and concentration-dependent manner that was abolished by the steroid receptor antagonist mifepristone (RU-38486 or RU-486). The stability of beta 2R mRNA was unchanged by Dex, and a nuclear run-on assay revealed that Dex approximately doubled the transcriptional rate of the beta 2R gene. These observations suggest that glucocorticoids act on steroid receptors to increase beta 2R expression by increasing the rate of beta 2R gene transcription.

Influence of warm ischemia on isolation and primary culture of hepatocytes from rat liver for a hybrid artificial liver

To assess the possibility of using hepatocytes from ischemic liver, as a bioreactor of a hybrid artificial liver, we investigated the influence of warm ischemia on the isolation and culture of hepatocytes in rats. Warm ischemia was induced by clamping the liver hilus and the animals were divided into 3 groups according to the duration of ischemia: group A (no ischemia), group B (10 minutes) and group C (20 minutes). Hepatocytes were isolated by the collagenase perfusion method and cultured for 5 days. The yield and viability of the isolated hepatocytes were lower in group C. Rate of attachment was decreased as the duration of ischemia increased. There was no significant difference observed in functions in culture. Sufficient hepatocytes, as a bioreactor, can be isolated and cultured from warm ischemic liver within 10 minutes. Though the number of available hepatocytes were diminished, hepatocytes procured from longer warm ischemic liver could be utilized as a bioreactor.

Purification and properties of L-galactono-gamma-lactone dehydrogenase, a key enzyme for ascorbic acid biosynthesis, from sweet potato roots

L-Galactono-gamma-lactone dehydrogenase (L-galactono-gamma-lactone:ferricytochrome c oxidoreductase [EC 1.3.2.3], GLDHase) which catalyzes the terminal step in the biosynthesis of L-ascorbic acid (AsA) has been purified from roots of sweet potato (Ipomoea batatas L., cv. Kintoki). Highly purified preparation of the GLDHase was obtained by three column chromatography steps with a recovery of ca. 1%, after solubilization from mitochondria in sweet potato roots. SDS-PAGE exhibited a single band at 56 kDa. In the native state, the apparent molecular mass of the enzyme was 56 kDa, based on a Sephadex G-100 gel filtration. The pI and optimum pH values were 5.8 and 7.9, respectively. The Km value for L-galactono-gamma-lactone was 0.12 mM. Substrate inhibition was obtained at concentrations greater than 4.2 mM. The enzyme was inhibited by p-chloromercuribenzoate (PCMB) and acriflavine, and the inhibition of acriflavine was diminished by the addition of FAD or FMN. The only effective substrate for the GLDHase was L-galactono-gamma-lactone.

Association of idiopathic hypopituitarism and syringomyelia

The magnetic resonance in an 8-year-old boy with hypopituitarism and cervical syringomyelia are presented. Magnetic resonance imaging of the brain clearly demonstrated syringomyelia in the cervical spinal cord and transection of the pituitary stalk, findings identical to those reported in the literature. Both disorders have been seen in association with a difficult labor, so we suggest that this is not a chance finding.