Structure-activity relationships of non-peptide vasopressin V1a antagonists: 1-(1-multi-substituted benzoyl 4-piperidyl)-3,4-dihydro-2(1H)-quinolinones

During our systematic studies on the arginine vasopressin receptor V1a-antagonistic activity of 1-(1-benzoyl substituted 4-piperidyl)-3,4-dihydro-2(1H)-quinolinones, we found a general substituent effect on the benzene ring. Hydrogen-bonding ability at the ortho position was especially important for enhancement of the affinity of multi-substituted analogs. Details of the syntheses and structure-activity relationships for this series are presented.

The relation between respiratory inhibition and uptake of 1-methyl-isoquinoline (MIQ+) in mitochondria

The effect of 1-methyl-isoquinoline (MIQ+) on the respiratory inhibition and the uptake of MIQ+ were measured using mouse liver mitochondria. MIQ+ inhibited the electron transport of complex I but did not inhibit the respiration of mitochondria with succinate as a substrate. MIQ+ was taken up by mitochondria in an energy dependent process. Tetraphenylboron enhanced the MIQ+ uptake by mitochondria and its inhibitory effect on respiration. The respiratory inhibition of mitochondria by MIQ+ resulted in release of MIQ+ from mitochondria in medium containing glutamate and malate. These characteristics of MIQ+, for uptake into mitochondria and respiratory inhibition, were similar to those of 1-methyl-4-phenylpyridine (MPP+). The IC50 of MIQ+ for respiratory inhibition was higher than that of MPP+, and the amount of MIQ+ uptake by mitochondria was smaller that of MPP+. The lower ability of MIQ+ for respiratory inhibition as compared to that of MPP+ must result from the lower lipophilic ability of MIQ+ than that of MPP+. These results show that, unlike MPP+, MIQ+ cannot act as a rapid neurotoxin. But, it does not eliminate the possibility that MIQ+ acts as a neurotoxin in the long-term, since MIQ+ was taken up in mitochondria and inhibited the respiration.

Gamma Knife radiosurgery for meningiomas: four cases of radiation-induced edema

We review 48 cases of meningioma treated with Gamma Knife radiosurgery. The mean marginal dose was 15 Gy and the mean follow-up was 12 months. Follow-up computed tomography and magnetic resonance imaging showed tumor shrinkage in 19 cases, central necrosis in 1 case, loss of contrast enhancement in 1 case, and no change in 27 cases. We noted 4 cases of radiation-induced edema in supratentorial meningiomas.

Uptake of 1-methyl-4-phenylpyridinium ion (MPP+) and ATP content in synaptosomes

Symptoms such as those in Parkinson's disease are known to be induced by the neurotoxin, 1-methyl-4-phenylpyridinium (MPP+). We tried to quantitatively measure synaptosomal MPP+ uptake using an MPP+ selective electrode to study the correlation between MPP+ uptake and respiratory inhibition. Synaptosomal MPP+ uptake was low but could be increased by the addition of glucose as an energy substrate, or increased with an increase in the concentration of MPP+. The rate of uptake was 0.2 nmol/mg protein/min at 50 microM MPP+. Tetraphenylboron (TPB+), which enhances cation permeability, increased MPP+ uptake, and the increase was proportional to the TPB+ concentration. When external MPP+ concentration was increased above 200 microM, ATP was depleted and the uptake of MPP+ decreased, which resulted in the release of intrasynaptosomal MPP+. MPP+ uptake was also decreased by depolarization of the membrane potential in synaptosomes. MPP+ was presumed to be distributed across both the synaptosomal and inner mitochondrial membranes, and to be affected by membrane potential as a lipophilic cation. When respiration of the inner mitochondria was inhibited by increasing the intrasynaptosomal MPP+ concentration, the concentration of MPP+ in cytosol was presumed to increase by the release of MPP+ from the mitochondria, and synaptosomal MPP+ uptake would then be decreased.

Purification and characterization of bleomycin hydrolase, which represents a new family of cysteine proteases, from rat skin

Bleomycin (BLM) hydrolase, which hydrolyzes the carboxyamide bond in the beta-amino-alanine moiety, was purified from newborn rat skin. The enzyme was purified 2,500-fold over the crude extract to apparent homogeneity in five steps in the presence of 2-mercaptoethanol: 45-55% ammonium sulfate fractionation, followed by chromatographies on Sephacryl S-200, DEAE-cellulofine, Phe-Superose, and Mono Q ion-exchange. The native enzyme had a molecular mass of 280 kDa according to gel filtration. The subunit molecular mass was estimated as 48 kDa by SDS-PAGE, indicating that the enzyme was comprised of six identical subunits. The amino acid sequence of its NH2-terminus was determined to be acetyl-Met-Asn-Asn-Ala-Gly-Leu-Asn-Ser-Glu-Lys-, which was not found in the amino acid sequence database. The optimum pH of the enzyme was 7.5 with pepleomycin (PLM). The Km and Vmax values were 2.1 mM and 6.8 mu mol center dot mg-1 center dot h-1 for PLM, and 1.8 mM and 7.2 mu mol center dot mg-1 center dot h-1 for BLM-A2, respectively. The enzyme activity was inhibited by iodoacetic acid, N-ethylmaleinimide (NEM), and p-chloromercuribenzoic acid (pCMB) as well as divalent cations such as Cu2+, Cd2+, Hg2+, and Zn2+. It was effectively inhibited by a cysteine protease inhibitor E-64. However, cystatins A and C did not inhibit the activity. BLM hydrolase exhibited broad aminopeptidase substrate specificity towards aminoacyl-beta-naphthylamides such as basic, neutral, and hydrophobic amino acid residues, as well as acidic residues. These results indicated that BLM hydrolase represents a new family of cysteine proteases. Western blotting and immunohistochemical analyses showed that BLM hydrolase is ubiquitous in various rat tissues but at low levels in lung and adult skin tissues, suggesting that this enzyme plays an important role in the metabolism of antibiotics.

Cloning and sequencing of a cDNA encoding a taste-modifying protein, miraculin

A cDNA clone encoding a taste-modifying protein, miraculin (MIR), was isolated and sequenced. The encoded precursor to MIR was composed of 220 amino acid (aa) residues, including a possible signal sequence of 29 aa. Northern blot analysis showed that the mRNA encoding MIR was already expressed in fruits of Richadella dulcifica at 3 weeks after pollination and was present specifically in the pulp.

Bufalin induces apoptosis and influences the expression of apoptosis-related genes in human leukemia cells

A low concentration of bufalin, a component of bufadienoides in the traditional Chinese medicine chan'su, was shown previously to induce differentiation of a broad range of human leukemia cell lines. In the present study, we found that bufalin at concentrations of 10(-7) M and higher induced apoptosis in human leukemia cells, such as HL60, ML1, but not in mouse leukemia M1 cells. A mere 15 min pretreatment of HL60 cells with 10(-6) M bufalin, followed by incubation for 15 h without bufalin, caused fragmentation of DNA and a decrease in cell viability, indicating that the signal for induction of apoptosis is triggered rapidly upon treatment with bufalin. Bufalin-induced apoptosis in HL60 cells was inhibited by ZnCl2, an inhibitor of endonuclease, but not by cycloheximide, an inhibitor of protein synthesis. Northern blot analysis revealed that the levels of expression of the c-myc and bcl-2 genes in HL60 cells decreased with time after treatment with bufalin. These results suggest that bufalin induces apoptosis specifically in human leukemia cells by altering the expression of these genes involved in apoptosis.

Geranylgeraniol is a potent inducer of apoptosis in tumor cells

We screened various isoprenoids to find inducers of apoptosis for human leukemia HL-60 cells, and found that GGO (geranylgeraniol) had the most potent apoptosis-inducing activity, as judged from DNA fragmentation in HL-60 cells. The apoptosis-inducing activity of GGO is concentration- and time-dependent. DNA synthesis by HL-60 cells was selectively inhibited on treatment with GGO. Besides HL-60 cells, apoptosis was induced by GGO in various tumor cell lines, including human myeloid multipotential leukemia K562, lymphoblastic leukemia Molt3, and colon adenocarcinoma COLO320 DM.

Purification and characterization of metallo-beta-lactamase from Serratia marcescens

Carbapenem-hydrolyzing beta-lactamase from Serratia marcescens FHSM4055 was purified 926-fold by means of carboxylmethyl Sephadex C-50, Sephacryl S-200, and Mono S column chromatography. The molecular weight was 30,000 by SDS-PAGE and the isoelectric point was 8.7. The enzyme activity was inhibited by EDTA, and restored by adding zinc (II) or manganese (II). It was inhibited by p-chloromercuribenzoate and iodine as well as the heavy metals, Hg (II), Fe (II), Fe (III), and Cu (II). These results indicate that the enzyme is a metallo-beta-lactamase and that the SH-group of only one cysteine residue probably binds to the metal ion, thus contributing to the stability of the enzyme active center. The specific constant (kcat/Km) showed that the enzyme hydrolyzed various beta-lactam antibiotics such as carbapenems, cephalosporins, moxalactam, cephamycins, and penicillins other than monobactams. Ampicillin and piperacillin with respective amino- and imino-groups, ceftazidime with a carboxypropyloxyimino-group, and cefclidin with a carbamoylquinuclidine-group were poor substrates among the beta-lactam antibiotics other than the monobactams tested. The plots of the turnover number (kcat) against pH for the hydrolysis of cephaloridine gave an asymmetrical curve with the 'tail' on the acid side (pK1, 5.9; pK2, 9.0; pK3, 10.8), whereas those of kcat/Km gave a bell-shaped curve (pK1, 5.8; pK2, 9.8). Both results suggest that two ionic forms of an intermediate yield the same product at different rates and that the enzyme is stable under alkaline conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Novel role of vitamin K2: a potent inducer of differentiation of various human myeloid leukemia cell lines

When myeloblastic ML1 cells were cultured in the presence of Vitamin K2 (menaquinone, VK2), the population of cells capable of reducing NBT increased to 83.5% at low VK2 concentration of 1 microM, indicating VK2 induces cellular differentiation. VK2 also exerted differentiation-inducing action on histiocytic U937 and promyelocytic HL60 cell lines. None of these effects were observed with Vitamin K1 (phylloquinone, VK1), suggesting the geranylgeranyl group of the side chain of VK2 to be essential to these effects. Combinations of VK2 with other differentiation-inducers such as interferon-gamma, retinoic acid, or camptothecin additively or synergistically induced the differentiation of HL-60 cells. These results suggest that VK2 may safely be used in differentiation therapy in combination with other inducers.

Localization of phosphoneuroprotein 14 (PNP 14) and its mRNA expression in rat brain determined by immunocytochemistry and in situ hybridization

Distribution and ultrastructural localization of a novel phosphoneuroprotein with a molecular mass of 14 kDa (PNP 14), and expression of its mRNA were studied in the adult rat central nervous system (CNS) by immunocytochemistry and in situ hybridization histochemistry. PNP 14 immunoreactivity was abundant in the molecular layer, present moderately in the granular layer, and rare in the Purkinje cell layer of the cerebellar cortex. No PNP 14 immunoreactivity was detected in the cerebellar medulla. In the forebrain, immunoreactivity was found in the hippocampus, striatum, and throughout the cerebral cortex, especially in layer V. Electron microscopic immunocytochemical observation in the cerebellar cortex revealed many PNP 14-immunoreactive axon terminals making synaptic contact with dendritic processes in both granular and molecular layers. PNP 14 immunoreactivity was present mainly in the cytoplasmic matrix in the presynaptic axon terminals. PNP 14 mRNA was localized in the granular layer of the cerebellar cortex, in the hippocampus, and in the cerebral cortex, suggesting that PNP 14 is synthesized in neurons of the granular layer and then transported to the molecular layer by axonal transport. These morphological findings suggest that PNP 14 is likely to modulate the function of selected CNS synapses.

Immunohistochemical and histochemical evidence for the presence of noradrenaline, serotonin and gamma-aminobutyric acid in chief cells of the mouse carotid body

The immunohistochemical study revealed tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), serotonin, glutamate decarboxylase (GAD) and gamma-aminobutyric acid (GABA) immunoreactivities in the mouse carotid body. TH and DBH immunoreactivities were found in almost all chief cells and a few ganglion cells, and in relatively numerous varicose nerve fibers of the carotid body. The histofluorescence microscopy showed catecholamine fluorescence in almost all chief cells. However, no PNMT immunoreactivity was observed in the carotid body. Serotonin, GAD and GABA immunoreactivities were also seen in almost all chief cells of the carotid body. From combined immunohistochemistry and fluorescence histochemistry, catecholamine and serotonin or catecholamine and GABA were colocalized in almost all chief cells. Thus, these findings suggest that noradrenaline, serotonin and GABA may be synthesized and co-exist in almost all chief cells of the mouse carotid body and may play roles in chemoreceptive functions.

Activation of mitogen-activated protein kinase cascade through erythropoietin receptor

Erythropoietin is a cytokine which specifically regulates differentiation and proliferation of erythroid progenitor cells. We show here that binding of erythropoietin to its receptor induced activation of protein tyrosine kinases including Jak2, and of Ras, Raf-1, mitogen-activated protein (MAP) kinase kinase and MAP kinases (ERK1 and ERK2). Taken together with other observations, erythropoietin receptor-mediated signal activates MAP kinase cascade, which is the common signaling pathway activated by other cytokines and growth factor receptors with tyrosine kinase activity.

Localization of pituitary adenylate cyclase-activating polypeptide and its messenger ribonucleic acid in the rat testis by light and electron microscopic immunocytochemistry and in situ hybridization

Pituitary adenylate cyclase-activating-polypeptide (PACAP) is a new member of the secretin/glucagon/vasoactive intestinal peptide family of peptides; it occurs as two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. Rabbit antisera against synthetic PACAP27 were characterized by enzyme-linked immunosorbent assay. One of the antisera, using a high antibody titer, recognized both PACAP27 and PACAP38 and was found useful for immunohistochemistry. The distribution and ultrastructural localization of PACAP-like immunoreactivity (PACAP-LI) in the rat testes at different stages of spermatogenesis were studied with this antiserum. Four oligonucleotide probes, each complementary to a different region covering a different intron-exon junction, were chosen to maximize hybridization based on the predicted secondary structure of PACAP messenger RNA. PACAP-LI was detected in the developing germ cells but not in either Sertoli or Leydig cells. Intense PACAP-LI was found in spermatids situated near the lumen of the seminiferous tubules. Lower levels of PACAP-LI were detected in spermatogonia and primary spermatocytes, but no PACAP-LI was found in mature spermatids, testicular spermatozoa, or epididymal spermatozoa. In spermatids, PACAP-LI was detected during the cap phase and acrosome phase but not in the maturation phase. At the ultrastructural level, numerous gold particles representing PACAP-LI were found in both acrosomal granules and acrosomal caps of spermatids, while a few particles were found in the Golgi complex. Very few gold particles were seen in the acrosome of mature spermatids and spermatozoa. PACAP-LI decreased and finally disappeared from spermatids during the late developmental stages. In situ hybridization indicated that most of the signal was detected near the perimeter of seminiferous tubules in early developing germ cells, especially in spermatogonia and primary spermatocytes, suggesting that transcription of the PACAP gene occurs in spermatogonia and primary spermatocytes. The processing of the prohormone appears to be slow, and mature PACAP only appears in spermatids. These morphological findings suggest that PACAP-like substances, synthesized by germ cells, participate in spermatogenesis, particularly spermiogenesis, probably by an autocrine and paracrine mechanism. However, the possibility that PACAP acts on the Sertoli and/or Leydig cells cannot be excluded.

Selective inhibitory effect of bufalin on growth of human tumor cells in vitro: association with the induction of apoptosis in leukemia HL-60 cells

We found that bufalin, an active principle of the Chinese medicine chan'su, has selective inhibitory effects on the growth of various human cancer cells. In order to examine whether the growth-inhibitory effect of bufalin on human cancer cells is associated with apoptosis, human leukemia cells were treated with bufalin. HL-60, ML1, and U937 leukemia cells treated with bufalin at 10(-8) M and above had condensed and fragmented nuclei. Flow cytometric analysis of these cells treated with bufalin showed fragmented DNA smaller than that of the G1 phase. DNA of HL-60 cells treated with bufalin showed a ladder pattern characteristic of apoptosis, as analyzed by agarose gel electrophoretic analysis. DNA synthesis and topoisomerase II activity of HL-60 cells were markedly inhibited as the concentration of bufalin was increased. The concentration needed for inducing apoptosis of HL-60 cells was 10(-8) M, which is comparable to that of camptothecin, but lower than those of other antitumor drugs such as cisplatin, VP16 and all-trans retinoic acid. Apoptosis was not observed when human mononuclear and polymorphonuclear cells were treated with 10(-6) M bufalin for 24 h. These results indicate the association of the growth-inhibitory effect of bufalin with the induction of apoptosis, at least in HL-60 cells, and suggest the usefulness of bufalin for differentiation-apoptosis-inducing therapy for cancer.

Cell cycle arrest and protein kinase modulating effect of bufalin on human leukemia ML1 cells

Bufalin, an active principle of the traditional Chinese medicine chan'su, has been proved to be a potent differentiation inducer in human leukemia cells. To study the mechanism of the differentiation of human leukemia ML1 cells induced by bufalin, we measured the effect of 10 nM bufalin on cell growth, activities of various protein kinases, and cell cycle. The ML1 cell growth was inhibited significantly at 24 hr and the inhibiting effect persisted for 6 days. Activities of PKC, PKA, cdc2 kinase and CK II in ML1 cells were changed early by bufalin; PKA and PKC activities were inhibited, and cdc2 kinase and CK II activities were increased. These results suggest that bufalin induces differentiation of ML1 cells by modulating several protein kinase activities in a distinct way from RA and 1 alpha, 25(OH) 2D3. Cell cycle changes, measured by flow cytometry, became evident at 12 hr after treatment of ML1 cells with bufalin and the cells were preferentially arrested in the G2/M phase. This effect of bufalin on the cell cycle of leukemia cells is similar to that of topoisomerase inhibitors. Indeed, the activity of topoisomerase II but not topoisomerase I of ML1 cells was inhibited remarkably by the treatment of the cells with 10 nM bufalin.

Relationships between serum saturated fatty acids and serum total cholesterol and HDL-cholesterol in humans

To investigate the effects of serum saturated fatty acids (FAs) on human cholesterol metabolism, total-cholesterol (T-C), HDL-cholesterol (HDL-C), T-C/HDL-C ratio, and FA composition [myristic acid (MA, 14:0), palmitic acid (PA, 16:0) and stearic acid (SA, 18:0)] were determined in serum from 115 men and 120 women (20-70 years old). MA, PA and SA were expressed as percentages of serum total FAs. Using multivariate analysis to account for the confounding effects of age, body mass index, drinking, and smoking it was found that SA was negatively correlated with T-C and T-C/HDL-C ratio in both men and women. In men MA was negatively correlated with HDL-C, and in women SA was positively correlated with HDL-C. Although PA was the major component of serum saturated FAs, PA had no significant relation to any cholesterol indices in either sex. These results suggest that serum MA may aggravate and serum SA may improve cholesterol metabolism, thereby influencing the risk for ischaemic heart disease.

Topoisomerase inhibitors potentiate the effect of retinoic acid on cell growth inhibition and induction of differentiation of leukemia HL-60 cells

Camptothecin (CPT) and 4'-demethylepipodophyllotoxin ethylidene-beta-D-glucoside (VP16) at concentrations of 0-10 nM and 0-400 nM, respectively, have weak synergistic effects with retinoic acid (RA) on the induction of differentiation and growth inhibition of HL-60 cells. However, pretreatment of HL-60 cells with the above respective concentrations of CPT or VP16 for 1 h, had no influence on the differentiation of HL-60 cells induced by the following treatment with RA: when HL-60 cells were pretreated with CPT or VP16 at concentrations of 80 nM or 16 microM, respectively, the following treatment with RA had a synergistic effect on the induction of differentiation and growth inhibition. Morphology and biochemical markers were used to show that the differentiation-inducing effect of RA on HL-60 cells was potentiated by pretreatment with higher concentrations of 80 nM CPT or 16 microM VP16. The present results suggest that combination of CPT or VP16 at low concentration with RA or pretreatment with higher concentrations of camptothecin or VP16, followed by RA treatment may be useful for increasing the differentiation effect of RA and decreasing the side effects of RA.

Monoclonal antibodies as probes to detect conformational changes in the rat cysteine proteinase inhibitor cystatin A

Five monoclonal antibodies (MAbs), 77, 114, 138, 175 and 187, were established for rat cystatin A. MAbs 77, 114, 138 and 175 were shown to belong to the IgG1 subclass, whereas MAb 187 was an IgM. These MAbs partially suppressed inhibitory activity of rat cystatin A to papain. Their epitopes were mapped in detail on the molecule by examining the reactivities of the MAbs with NH2-terminally truncated forms and fragments of rat cystatin A by an enzyme-linked immunosorbent assay (ELISA), and by reactivity with the inhibitor on immunoblotting. In competitive binding assays the MAbs did not compete with each other, indicating that the epitopes recognized by these MAbs were substantially different. The conformational epitope recognized by the three MAbs 114, 138 and 175 belonged to one group that was highly sensitive to denaturation, but those epitopes were unchanged by NH2-terminal truncation. MAb 187 was able to recognize a linear epitope present in amino acid residues 15-50 in the NH2-terminal region. MAbs 77 and 114 reacted weakly with mouse cystatin A but not at all with human cystatin A, whereas MAb 187 reacted similarly with mouse cystatin A but at about half that level with human. The MAbs produced in this study should be useful tools for detecting conformational changes in the rat cystatin A molecule.

A new brain-specific 14-kDa protein is a phosphoprotein. Its complete amino acid sequence and evidence for phosphorylation

We previously reported a new brain-specific protein with a molecular mass of 14 kDa, specifically present in synapses around neurons but not in glial cells [Nakajo, S., Omata, K., Aiuchi, T., Shibayama, T., Okahashi, I., Ochiai, H., Nakai, Y., Nakaya, K. & Nakamura, Y. (1990) J. Neurochem. 55, 2031-2038]. In the present study, we determined the primary structure of this protein, found that it is phosphorylated in vitro and in vivo, and designated it phosphoneuroprotein 14 (PNP 14). The protein is a single polypeptide with 134 amino acid residues (molecular mass = 14122 Da), and it contains a hydrophobic region at the center of the molecule. The carboxy-terminal region has all seven proline residues, and is rich in glutamic acid, which contribute to the acidic property of the protein. The amino-terminal region possesses four unique repetitive motifs, Glu(Ser)-Lys-Thr-Lys-Glu(Gln)-Gly(Gln)-Val(Ala). When a cytosolic fraction prepared from rat cerebral cortex was incubated with [gamma-32P]ATP, 32P was incorporated into PNP 14. Phosphorylated PNP 14 was immunoprecipitated from rat brain synaptosomes labeled metabolically with [32P]orthophosphate. Injection of [32P]orthophosphate into the third ventricle of rat brain resulted in incorporation of radioactive phosphate into PNP 14. We have also found that Ca2+, calmodulin-dependent protein kinase II phosphorylates serine residue(s) of PNP 14 in vitro. The results suggest that PNP 14 may be important to neuronal cells, but not to glial cells, and that its physiological functions may be controlled by the phosphorylation reaction.

Cell and tissue distribution and developmental change of neuron specific 14 kDa protein (phosphoneuroprotein 14)

In the present paper, the distribution of a neuron-specific phosphoneuroprotein 14 (PNP 14) in cell and tissue was investigated in detail by the immunoblot method using affinity-purified antibody against this protein. The immunoblot of the supernatant fractions of various tissue homogenates of rat clearly demonstrated that PNP 14 was enormously rich in the brain. The content in rat brain was as much as 0.1% of the homogenate. The immunocytochemical study showed that the protein was localized at nerve endings in the cerebellum. Existence of the protein was also confirmed in cultured neuronal cells from postnatal rat midbrain, but not in glial cells. Examination of subcellular localization of PNP 14 indicates that the protein was present in synaptic plasma membranes and synaptic supernatant fractions, but not in synaptic vesicles. During the development of rat brain, PNP 14 came into existence after birth and it's amount linearly increased to a maximum at 21-28 days after birth. The content of the protein then remained at the same level for more than 10 months. We concluded that this protein is neuron specific and supposed that it may be involved in neuronal formation and function.

Gamma-aminobutyric acid (GABA) immunoreactivity in the mouse adrenal gland

Gamma-aminobutyric acid (GABA) immunoreactivity was revealed by immunocytochemistry in the mouse adrenal gland at the light and electron microscopic levels. Groups of weakly or faintly GABA immunoreactive chromaffin cells were often seen in the adrenal medulla. By means of immunohistochemistry combined with fluorescent microscopy, these GABA immunoreactive chromaffin cells showed noradrenaline fluorescence. The immunoreaction product was seen mainly in the granular cores of these noradrenaline cells. These results suggest the co-existence of GABA and noradrenaline within the chromaffin granules. Sometimes thick or thin bundles of GABA immunoreactive nerve fibers with or without varicosities were found running through the cortex directly into the medulla. In the medulla, GABA immunoreactive varicose nerve fibers were numerous and were often in close contact with small adrenaline cells and large ganglion cells; a few, however, surrounded clusters of the noradrenaline cells, where membrane specializations were formed. Single GABA immunoreactive nerve fibers, and thin or thick bundles of the immunoreactive varicose nerve fibers ran along the blood vessels in the medulla. The immunoreaction deposits were observed diffusely in the axoplasm and in small agranular vesicles of the GABA immunoreactive nerve fibers. Since no ganglion cells with GABA immunoreactivity were found in the adrenal gland, the GABA immunoreactive nerve fibers are regarded as extrinsic in origin.

Orally active, nonpeptide vasopressin V1 antagonists. A novel series of 1-(1-substituted 4-piperidyl)-3,4-dihdyro-2(1H)-quinolinone

A series of compounds has been synthesized and demonstrated to be antagonists of V1 receptors both in vitro and in vivo. These compounds are structurally related to the 1-(4-piperidyl)-2(1H)-quinolinones, including OPC-21268, an orally bioavailable AVP V1 antagonist with high V1 specificity. It has been found that the introduction of an acetamide group on the terminal alkoxy chain of 41-44 leads to an increase in oral activity. Certain of these compounds may have efficacy in the study of AVP V1 receptors.

Differentiation of promyelocytic leukemia cells HL-60 induced by daidzein in vitro and in vivo

We have screened more than one thousand synthetic and natural chemicals to explore differentiation inducers and found that daidzein has potent differentiation-inducing activity for human leukemia HL-60 cells, both in vitro and in vivo. In vitro study showed that daidzein at concentrations exceeding 10 micrograms/ml caused inhibition of HL-60 cells; and it induced differentiation of the cells into granulocytic lineage as judged by NBT reduction activity, phagocytic ability and morphological characteristics. Flow cytometry study indicated that daidzein arrested HL-60 cells in the G1 phase. The growth of HL-60 cells in the subrenal capsules of mice and in diffusion chambers implanted into the peritoneal cavities of mice was inhibited by 50 mg/kg daidzein. HL-60 cells treated with daidzein in vivo also exhibited characteristic morphological changes of matured cells. Moreover, the colony forming efficiency of HL-60 cells in diffusion chambers in mice was markedly inhibited by the administration of daidzein.