Effects of ethanol and acetaldehyde on the contraction of cultured Ito cells

The effects of ethanol (Et-OH) and acetaldehyde (Ac-CHO) on the contraction of cultured Ito cells were studied using a time-interval videotape recorder (VTR). Ito cells were isolated from Wistar rats and cultured for 4 days. The motion of the cells was recorded by VTR and the sequential changes of the surface area of the each cell were evaluated by an image analyzer. No contraction of Ito cells was observed after incubation with Et-OH (100 mM) or Ac-CHO (500 microM) alone. Ten nanomoles endothelin-1 (ET-1) caused Ito cells to contract gradually. Pre-incubation of ET-1 with Ac-CHO at 37 degrees C for 1 hr inhibited the contraction of Ito cells completely. This inhibition was not seen in pre-incubation of ET-1 with Et-OH. In addition, the Ito cells which were pre-cultured with Ac-CHO for 6 hr did not contract at all after incubation with ET-1. In the isoelectric focusing of ET-1, a band was clearly seen at pI 4.6 after the treatment with Et-OH as well as non-treated ET-1. Two extra bands of ET-1 appeared in the anodic side of the gel after treatment with Ac-CHO, indicating the conformational changes of ET-1. These results indicated that the contraction of Ito cells induced by ET-1 was inhibited completely by Ac-CHO. This inhibitory effect of Ac-CHO was thought to be caused by binding Ac-CHO to ET-1 itself or to ET-1 receptors.

Correlation between tumor proliferation and tumor tissue level of urokinase-type plasminogen activator

We established a xenotransplanted human colon cancer strain, TK-3, which produces urokinase-type plasminogen activator (U-PA) and carcinoembryonic antigen (CEA) simultaneously. Immunohistochemical staining of U-PA revealed that U-PA was located in the cytoplasm of cancer cells. Using TK-3, we investigated whether the tissue level of U-PA changed when the tumor proliferated locally. The mice were divided into three groups: mice of group A, B and C were sacrificed at 4, 5 and 6 weeks after tumor inoculation, respectively. The tissue level of U-PA was 0.78 +/- 0.183 ng/mg protein in group A, 0.95 +/- 0.189 in group B and 1.13 +/- 0.311 in group C. The values of groups B and C increased significantly compared with those of group A, and the tumor weight in each group showed a similar increase. The level of plasminogen activator inhibitor type 2 also increased (0.14 +/- 0.078 ng/mg protein in group A, 0.17 +/- 0.096 in group B, 0.24 +/- 0.172 in group C). On the other hand, the tissue level of CEA did not change significantly (78 micrograms/g tissue in group A, 88 in group B, 76 tissue in group C), and no correlation was observed between the tissue levels of U-PA and CEA. These results suggest that U-PA plays an important role not only in metastasis, but also in local tumor proliferation, and that its biological action in the autocrine system is independent of CEA.

Genetic factors related to the development of carcinoma in digestive organs in alcoholics

Heavy drinkers do not always develop alcoholic liver disease or cancer of the digestive organs, indicating that genetic factors may be involved. Recently, the presence of genetic polymorphisms of cytochrome P4502E1 (2E1) was confirmed. The genotype of 2E1 was separated into three types; type A which is homozygous for the c1 gene, type B which is heterozygous for the c1 and c2 genes, and type C which is homozygous for the c2 genes. In the present study the relationship between genotypes of 2E1 and digestive diseases, including alcoholic liver disease, was analyzed. In healthy controls, the prevalence of types A, B and C was 69%, 31% and 0%, respectively. In patients with esophageal cancer, four out of five patients (80%) were type B, and the prevalence of type B was significantly higher than that in normal controls. These results suggest that the c2 gene of 2E1 may be related to the development of esophageal cancer. In patients with gastric disease, the prevalence of types A and B was 72% and 28%, respectively. In patients with large bowel disease, the prevalence of type A was 83-100%, significantly higher than that in healthy controls. These results suggest that the c2 gene of 2E1 may not be related to the development of large bowel disease. However, the possibility should be considered that the c1 gene of 2E1 may link to its development. In this study, the relationship between the genotype of 2E1 and alcoholic liver disease was also analyzed. All patients with alcoholic liver disease, including one hepatoma, had the c2 gene but not the c1 gene. The frequency of the c2 gene was quite different from that in non-alcoholic liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ethanol and acetaldehyde on the maturation of hepatic secretory glycoproteins

The effects of ethanol and acetaldehyde on the maturation and secretion of hepatic glycoproteins in cultured rat hepatocytes were analysed using a pulse-chase labelling method and autoradiography following two-dimensional gel electrophoresis. A spot for transferrin was detected at mol. wt 77,000 and pI 5.2-5.4 on the autoradiogram in the control culture. The spot for transferrin shifted to the more basic isoforms by treatment for 3 hr with monensin or tunicamycin. The spot for transferrin also shifted to the more basic side by treatment with acetaldehyde for 3 hr or by additional treatment for 3 hr following pretreatment with ethanol for 6 hr. However, the shift of transferrin was not observed following treatment with ethanol for 3 hr. These results suggest that glycosylation of secretory glycoproteins in the Golgi apparatus is inhibited by acetaldehyde, but not by ethanol itself, and that this inhibition may play an important role in the development of alcoholic liver disease.

Serotonergic measures in blood and brain and their correlations in rats treated with tranylcypromine, a monoamine oxidase inhibitor

Tranylcypromine, a monoamine oxidase inhibitor, was administered to male Wistar rats in order to investigate its effects on blood and brain serotonin related substances after 1, 4, and 24 h following injection and possible relations between serotonergic measures in central nervous system and periphery. The dose of the drug tested was responsible for an increase in blood serotonin with a simultaneous fall in its metabolite 5-hydroxyindoleacetic acid (5-HIAA) compared to either pretreatment or control values. These changes were the most marked after 4 and 24 h following tranylcypromine injection. Almost all brain areas studied (cerebellum, medulla, hypothalamus, striatum, midbrain, hippocampus, and cortex) were to be affected by monoamine oxidase inhibitor treatment. They exhibited a rise in serotonin content starting from 1 h after drug administration and lasted in many parts of the brain up to 24 h, which was accompanied by a parallel fall in 5-HIAA level. All these changes were significant when compared to baseline and control values. Alterations in blood serotonin correlated positively with changes in brain serotonin and negatively with brain 5-HIAA, while the opposite pattern of correlations was found regarding blood 5-HIAA and the content of serotonin and 5-HIAA in various brain areas studied. This pattern of correlations speaks in favor of an existence of mutual relations between blood and brain serotonin related substances. Our results suggest that blood serotonin and 5-HIAA may serve as an index of monoamine oxidase inhibitor action on the central serotonergic system.

Differentiation-dependent expression of sialyl stage-specific embryonic antigen-1 and I-antigens on human lymphoid cells and its implications for carbohydrate-mediated adhesion to vascular endothelium

Expression of two developmentally regulated carbohydrate antigens, the sialyl stage-specific embryonic antigen-1 (SSEA-1) and I-antigens, in human lymphocytes and lymphocytic leukemia cells was investigated using specific monoclonal antibodies. Sialyl SSEA-1 was expressed only on natural killer (NK) cells, and was essentially absent on resting mature T and B cells among normal peripheral lymphocytes. On the other hand, the I-antigen was strongly expressed on virtually all mature B cells, moderately expressed on most mature T cells, but not expressed on NK cells in normal donors. Expression of the two antigens on normal T and B cells was reversible; in vitro stimulation of normal lymphocytes with concanavalin A (Con A) resulted in the loss of I-antigen and appearance of sialyl SSEA-1 on CD3+ T blasts, whereas stimulation with pokeweed mitogen led to loss of I-antigen expression and appearance of sialyl SSEA-1 antigen on CD19+ B blasts. Among lymphocytic leukemia cells, sialyl SSEA-1 was detected primarily on leukemia cells having immature properties such as most common acute lymphocytic leukemia (cALL) blasts, while the I-antigen was frequently expressed on malignant cells having relatively mature properties, such as those found in adult T-cell leukemia or chronic lymphocytic leukemia, and only occasionally on cALL blasts. Among normal peripheral lymphocytes, the sialyl SSEA-1+I-antigen- NK cells selectively underwent E-selectin (ELAM-1, endothelial-leukocyte adhesion molecule-1)-dependent adhesion to endothelial cells, while the I-antigen+sialyl SSEA-1- mature T and B cells did not, in line with the recent finding that sialyl SSEA-1 serves as a specific ligand for E-selectin. Con A blasts, which are sialyl SSEA-1+I-antigen-, also exhibited significant E-selectin-dependent adhesion to endothelial cells. These results indicate that expression of the sialyl SSEA-1 and I-antigens varies alternately depending on the differentiation/activation status of the lymphocytes, and that this at least partly regulates the behavior of lymphocytes at the vessel wall.

Ethanol and acetaldehyde metabolism in cultured rat hepatocytes

In the present study, ethanol (Et-OH) and acetaldehyde (Ac-CHO) metabolism in primary cultured hepatocytes isolated from chronically alcohol-fed rats were analysed to elucidate the characteristics of the metabolism of Ac-CHO produced through the non-alcohol dehydrogenase (non-ADH) pathway. Dimethyl sulfoxide was added to the culture medium to prevent a decrease in P450 IIE1 activity. Ac-CHO formed in the culture medium was trapped by semicarbazide to prevent a reutilization of Ac-CHO by hepatocytes. The degradation rate of Ac-CHO in the liver was similar in alcohol and non-alcohol-treated rats. Therefore, the characteristic of the metabolism of Ac-CHO in the chronically alcohol-fed rats was not clarified in this study. The possibility that the Ac-CHO trapping by semicarbazide was only 70%, and that the remaining Ac-CHO was reutilized for oxidation in the hepatocytes, should be considered. Some method to trap Ac-CHO completely in the culture medium is needed to clarify the characteristics of Ac-CHO metabolism.

Role of the aldehyde dehydrogenase-1 isozyme in the metabolism of acetaldehyde

At least four types of aldehyde dehydrogenase (ALDH) isozymes exist in human liver: acetaldehyde (Ac-CHO) is metabolized mainly by ALDH2. However, the role of ALDH1 in Ac-CHO metabolism is not well known, because ALDH1 deficiency is rare. In the present study, changes in blood levels of Ac-CHO were analyzed in a person with ALDH1 deficiency who is also heterozygous for the ALDH2 alleles, and subjects with normal ALDH1, in order to clarify the roles of ALDH1 in the metabolism of Ac-CHO. By isoelectric focusing analysis of ALDH in red blood cells (RBC), the ALDH1 band was not detectable in a male subject, indicating ALDH1 deficiency. In this subject, ALDH1 activity was nearly null, but the activities in his wife and two children were normal. Serial changes of blood Ac-CHO levels following a small amount of ethanol were analyzed. The peak levels of Ac-CHO were not different between the subject with ALDH1 deficiency and the person with normal ALDH1. However, the decrease from the peak values of Ac-CHO was clearly slower in the deficient subject than in ALDH1 normal subjects. Changes in Ac-CHO in blood were also analyzed in vitro. Ac-CHO metabolism by RBC from the ALDH1 deficient subjects was clearly slower than in those from controls. These results indicate that ALDH1 plays an important role in the metabolism of Ac-CHO in blood.

Blood-brain barrier transfer of L-Trp and alpha-MTrp in Li-treated rats

Blood-brain barrier (BBB) transport for L-Trp and alpha-methyl-L-tryptophan was evaluated in Li-treated rats. Five different brain areas as well as left to right differences were examined. No left to right difference in the PS product was observed. Lithium treatment had a significant effect on the plasma concentration of Val, Leu and Ile but no effect on plasma total or free Trp. The ratio of plasma Trp to the sum of Leu, Val, Ile, Phe, Met and Tyr is increased in the Li-treated rats but not significantly. However, the ratio of Trp/(Val+Leu+Ile) is significantly increased in the Li-treated rats. The Km apparent (Kmapp) for the BBB Trp transport is significantly decreased (affinity of the carrier for Trp is increased) in the Li-treated rats. A decrease in the Kmapp is one of the possible factors responsible for an increase in the brain Trp concentration and subsequent increase in the brain serotonin synthesis in Li-treated rats.

The role of growth factor in wound healing

A pig wound healing model was developed to study the morphological processes involved in incisional and excisional wound healing, the immunohistochemical localization of TGF-alpha in wound healing, and the latter's relevance. In incisional wounds, a few layers of epidermis were regenerated after only 32 hours. In contrast, several layers of epidermis were regenerated on day 7 in excisional wounds. In general, the incisional wound model is useful for evaluating tensile strength, while the excisional wound model is suitable for evaluating epidermal regeneration. Immunohistochemical study showed that keratinocytes migrating from wound edges expressed TGF-alpha very faintly, while TGF-alpha was present prominently in the upper several layers of the epidermis adjacent to the wound, which resembled normal epidermis and showed no changes during the wound healing process.

Autoradiographic study of peripheral benzodiazepine receptors in animal brain tumor models and human gliomas

In vitro binding of [3H]PK-11195 (1-(2-chlorophenyl)-N-methyl-(1- methylpropyl)-3-isoquinoline carboxamide) in rodent AA ascites and C6 glioma as well as in human gliomas was investigated. The Bmax (mean +/- S.D.) of AA ascites tumor and C6 glioma is 1.39 +/- 0.15 pmol/mg tissue and 4.50 +/- 0.76 pmol/mg tissue, respectively. This Bmax is 9 and 30 times, respectively, higher than the one found in the rat cortex (0.15 +/- 0.03 pmol/mg tissue). A Bmax of 1.26 +/- 0.24 pmol/mg tissue and 0.64 +/- 0.08 pmol/mg tissue was found in human malignant and low grade gliomas respectively. This Bmax value should be compared to 0.35 +/- 0.04 pmol/mg tissue found in the normal human cortex. There are significant (P less than 0.05) differences between Bmax in tumors and normal cortex. There was no significant difference in KD between the malignant and low grade gliomas. C6 glioma has a KD significantly greater than rat cortex. In some cases of human low grade gliomas, kinetic measurements suggested the presence of two affinity receptor sites. However, at this time, heterogeneity of the tissue cannot be excluded as being at least in part a source of this.

Endothelins inhibit serotonin-induced platelet aggregation via a mechanism involving protein kinase C

Endothelins are a family of three peptides that act as local hormones released by the endothelium. They were found to inhibit rabbit and dog platelet aggregation in vivo, but no effect was observed in vitro. In order to investigate the possible interaction between endothelins and human platelet serotonin receptors, their effects on platelet aggregation induced by serotonin was studied. Endothelin-1, -2 and -3 had a dual action, on platelet aggregation and calcium mobilization induced by serotonin. When added at the same time as serotonin, endothelin potentiated the response to the amine. On the contrary, preincubation of platelet suspension with endothelin resulted in a concentration-dependent inhibition of the serotonin-mediated platelet response. Moreover, endothelin-1 inhibited serotonergic amplification of epinephrine-induced aggregation of platelets. We hypothesize that endothelins can bind to the platelet membrane and interact with serotonin receptors. The diverse effect of endothelins on serotonin-induced aggregation and calcium mobilization may be due to stimulation of protein kinase C.

The 55-kilodalton protein in an oriC complex fraction is glycogen synthase

Three proteins with molecular masses of 35, 55, and 75 kDa were found in an oriC complex fraction after purification through CsCl density gradient centrifugation (W. G. Hendrickson, T. Kusano, H. Yamaki, R. Balakrishnan, M. King, J. Murchie, and M. Schaechter, Cell 30:915-923, 1982). Of these three proteins, the 55-kDa protein was determined to be glycogen synthase on the basis of the N-terminal amino acid sequence and the molecular weight. The oriC complex was formed in glgA mutant cells, which produce no detectable glycogen, as well as in wild-type cells. None of the 35-, 55-, and 75-kDa proteins were detected in the fraction from this mutant. The results indicate that these proteins were not constituents of the oriC complex.

Expression of the angiotensinogen gene and localization of its protein in the human heart

BACKGROUND

There have been no reports on the presence of the tissue renin-angiotensin system in the human heart, although the presence of angiotensinogen has been described in the animal heart.

METHODS AND RESULTS

To determine whether angiotensinogen is synthesized in the human heart, we examined angiotensinogen messenger RNA (mRNA) synthesis in autopsy hearts by using ribonuclease protection assay. As a result, angiotensinogen mRNA was detected in the atrial muscle, muscles of the conduction system, and the left ventricular wall. In the left ventricular wall, mRNA expression was more prominent in the subendocardial muscles than in the midcardial or epicardial muscles. Using a monoclonal antibody to human angiotensinogen in immunoblotting experiments, we detected two closely spaced bands at approximately 70 kd in the heart, which was quite consistent with the human angiotensinogen molecule. Immunohistochemical studies with this monoclonal antibody demonstrated intense immunoreactivity in the atrial muscles, the muscles of the conduction system, and those of the subendocardial layers.

CONCLUSIONS

We conclude that angiotensinogen was synthesized in the human heart. It was evident that the localization of angiotensinogen was not ubiquitous in the cardiac muscles, showing its predilection for the atrial muscles, muscles of the conduction system, and subendocardial layer of the left ventricle.

[Microheterogeneity of serum glycoproteins in alcoholic liver disease]

It has been reported that microheterogeneity (M-HT) of serum glycoproteins including transferrin is found in alcoholic liver disease (ALD). In the present study, M-HT of serum glycoproteins in ALD patients was analyzed using the Western blotting technique after isoelectric focusing. M-HT was found in serum alpha 1-antitrypsin, alpha 2-macroglobulin, ceruloplasmin, alpha 1-acid glycoprotein and hemopexin as well as transferrin, but not in serum prealbumin. M-HT disappeared following treatment with sialidase in one group of glycoproteins, but not in another group of glycoproteins. In hemopexin, M-HT was recognized only after treatment with sialidase. These results suggest that mechanisms of the appearance of M-HT of serum glycoproteins in ALD may differ. One mechanism is the interference of glycosylation of glycoproteins in the Golgi apparatus, and another is the decrease of asialo-protein receptors in hepatocytes.

Blood serotonergic mechanisms in type 2 (non-insulin-dependent) diabetes mellitus

Serotonin (5-hydroxytryptamine, 5HT) is believed to play a role in vasospasm and increased platelet aggregability that in turn could contribute to atherosclerosis. The present study was designed to evaluate a possible participation of serotonin in the development of vascular complications in diabetes mellitus. Whole blood and plasma serotonin, the platelet uptake and release of the amine and serotonin- induced platelet aggregation were studied in 32 patients with Type 2 diabetes. The patients were divided into three groups according to the presence and advancement of retinopathy. Mean levels of blood serotonin content were significantly lower in diabetic patients. The concentration of the amine in the plasma was markedly increased in diabetes. It was correlated with vascular changes of the retina. We established that platelets from diabetic patients took up less serotonin when compared to the control group. Concomitantly enhanced spontaneous release of 5HT from platelets was observed. The platelets of diabetic patients showed increased response to serotonin. There was a relation between serotonin-induced aggregation and the presence of retinopathy. These results suggest that serotonin may be involved in the pathogenesis of diabetic vasculopathy.

Influence of the tumor mass on the valine rate constants and on valine incorporation into proteins in an experimental brain tumor model

Quantitative autoradiography was used to estimate regional transfer coefficients for valine incorporation and the rate of valine (exogenous and total) incorporation into proteins in an implanted brain-tumor model (AA ascites tumor). Special attention was paid to the evaluation of the tumor mass influence on the transfer coefficients and the rate of incorporation. The size of the tumors used in this study ranged from 2 to 5 mm in diameter. Nine groups of two to three animals each were used to determine the transfer coefficient. The transfer coefficients for movement of the label between different compartments were significantly greater in the tumor than in the normal brain. There is no tumor mass effect on the transfer coefficients or the rate of valine incorporation into proteins in surrounding or remote brain structures. The ratio between specific radioactivities of the free value in tissue and plasma was also measured. Results indicate that approximately the same fraction of the total valine is recycled in cortex as in the tumor tissue. The mean rates of exogenous valine incorporation into proteins (nmol g-1 min-1) is about one order of magnitude greater in the tumor than in the contralateral parietal cortex.

Effects of vitamin A on collagen metabolism by cultured rat liver cells

Conflicting results have been reported concerning the phenotypes of collagen produced by cultured Ito cells. These variations may be attributed to differences in pretreatment, i.e., with or without vitamin A to facilitate the separation of Ito cells. In the present study, the effects of vitamin A on collagen metabolism by Ito cells and hepatocytes of rats were analyzed. In cultured Ito cells, staining reactions to type I collagen increased, and those to type IV collagen and laminin decreased after pretreatment with vitamin A. The rate of collagen synthesis by Ito cells decreases significantly by treatment with vitamin A. The decrease was clearer in degraded collagen than in intact collagen. The synthesis of type I collagen increased and that of type IV collagen significantly decreased in Ito cells by treatment with vitamin A. In the hepatocytes, the staining reaction to type I collagen increased with vitamin A pretreatment. The net collagen and type III collagen synthesis in hepatocytes decreased by treatment with vitamin A. These results indicate that vitamin A modifies collagen metabolism in different cell types in different ways.

Plasminogen activators and plasminogen activator inhibitor 1 before and after venous occlusion of the upper limb in thromboangiitis obliterans (Buerger's disease)

Plasma levels of plasminogen activators (t-PA, u-PA) and their inhibitor (PAI-1) were studied in patients suffering from Buerger's disease and healthy volunteers before and after 15 minutes of venous occlusion test. The baseline levels of t-PA in group of patients did not differ from those of controls. On the contrary patients with Burger's disease showed a marked increase in u-PA antigen concentrations with concomitant decrease in PAI-1 antigen levels. During venous stasis t-PA antigen concentrations increased in all subjects, however it was much pronounced in controls. Venous occlusion resulted in significant decrease in free PAI-1 levels in the group of patients only. In conclusion, Buerger's disease is associated with the endothelial derangement with increased u-PA release and decreased PAI-1 release, which does not influence the function of fibrinolytic system. The fact that the reduced response of the endothelium to release t-PA after venous stasis goes in parallel with marked decrease in PAI-1 antigen levels seems to suggest that patients suffering from Buerger's disease are not at high risk of intravascular fibrin deposition.

Purification and characterization of formaldehyde dehydrogenase from rat liver cytosol

Formaldehyde dehydrogenase was purified to electrophoretic and column chromatographic homogeneity from rat liver cytosolic fraction by a procedure which includes ammonium sulfate precipitation, DEAE-cellulose-, hydroxyapatite-, Mono Q-chromatography, and gel filtration. Its molecular mass was estimated to be 41 kDa by gel filtration and SDS-PAGE, suggesting that it is a monomer. It utilized neither methylglyoxal nor aldehydes except formaldehyde as a substrate. It has been reported that liver class III alcohol dehydrogenase and formaldehyde dehydrogenase are the same enzyme and oxidize formaldehyde and long chain primary alcohols. However, the enzyme examined here did not use n-octanoi as a substrate. The Km values for formaldehyde and NAD+ were 5.09 and 2.34 microM at 25 degrees C, respectively. The amino acid sequences of 10 peptides obtained from the purified enzyme after digestion with either V8 protease or lysyl endopeptidase were determined. From these results, the enzyme was proved to be different from the previously described mammalian formaldehyde dehydrogenase and is the first true formaldehyde dehydrogenase to be isolated from a mammalian source.