Thrombin-induced platelet aggregation, phosphoinositide metabolism and protein phosphorylation in NIDDM patients treated by diet, sulphonylurea or insulin

We studied thrombin-induced metabolism of phosphoinositide, protein phosphorylation and platelet aggregation in platelets from 32 NIDDM patients and 12 control subjects. To clarify the effect of diet, sulphonylureas, or insulin treatment, the subjects were divided into three groups based on the type of treatment. Thrombin-induced platelet aggregation was measured with an aggregometer. Low-dose thrombin (0.25 U/ml)-stimulated platelet aggregation in diabetic patients was significantly increased compared with the control subjects. Platelet aggregation in the sulphonylurea and insulin groups was significantly lower than in the diet group. On the other hand, in platelets incubated with [32P]orthophosphate, thrombin-induced incorporation of 32P radioactivity into phosphatidic acid (PA) was significantly lower in the sulphonylurea and insulin groups than in the diet group. Thrombin-induced incorporation of [32P] radioactivity into phosphatidylinositol (PIP) for 10 s was significantly higher in the sulphonylurea group than in the diet group. There were no differences in thrombin-induced 47 kDa protein phosphorylation between platelets from the diet, sulphonylurea, or insulin groups. These results suggest that sulphonylureas and insulin induce suppression of thrombin-induced activation of phospholipase C, which mediates hydrolysis of PIP and PIP2 and production of PA, which leads to inhibition of platelet aggregation.

Appearance of spermatozoon after administration of mast cell blocker to a patient with azoospermia

Since a close relationship has been suggested to exist between testicular disfunction and the increased mast cells in the testis, we used a mast cell blocker for the treatment of patients with idiopathic infestility. An infertile male with idiopathic azoospermia was treated with administration of a mast cell blocker, tranilast for one year. The patient was found to have sperm within his ejaculate. However, the ultimate goal of pregnancy was not achieved by the microfertilization technique. To evaluate the possible significance of this new treatment, further basic research will be needed to clarify the relationship between mast cell proliferation and impaired testicular function.

Inhibitory effect of enalapril on the constriction of the ductus arteriosus in newborn rats

Caesarean newborn rats were given subcutaneously enalapril maleate (EM), an angiotensin-converting enzyme inhibitor, (1) immediately or (2) 180 min after delivery. The ductus arteriosus (DA) in these newborn pups was calibrated 30, 60 and 90 min after the EM-treatment. The results were as follows: (1) DA calibers of the pups given 10 or 50 mg/kg EM just at caesarean delivery remained significantly larger than those of the controls thereafter until 90 min. (2) The DA was completely closed 180 min after caesarean delivery. However, with 50 mg/kg EM given at this time, the DA was temporarily re-opened and then constricted. It is concluded that, in newborn rats, EM has the direct inhibitory action on the constriction of the DA, and that it also has the re-opening action on the once-constricted DA.

The gradient of basic fibroblast growth factor concentration in human pancreatic cancer cell invasion

It has been reported that basic fibroblast growth factor (b-FGF) is overexpressed in human pancreatic cancer cells, and that the overexpressed b-FGF contributes to the disease progression (Yamanaka et al. Cancer Res. 53, 5292-5297, 1993). Pancreatic cancer aggressively invades surrounding tissues by penetrating basement barriers. Thus, effect of b-FGF on pancreatic cancer, cell invasion to Matrigel basement membrane, was studied. The high gradient of b-FGF increased the invasiveness of human pancreatic cancer cells in a dose-dependent manner. Furthermore, the invasiveness of the cells was suppressed by anti-FGF receptor antibody. These results suggest that b-FGF plays an important role in human pancreatic cancer cell invasion to basement membrane.

Possible involvement of peripheral 5-HT4 receptors in copper sulfate-induced vomiting in dogs

The involvement of visceral afferent fibers and 5-HT3 or 5-HT4 receptors in the vomiting induced by oral administration of copper sulfate was investigated in beagle dogs. Vomiting induced by copper sulfate (100 mg/kg) was inhibited markedly by bilateral abdominal vagotomy and bilateral greater splanchnic nerve section. The vomiting induced by copper sulfate was inhibited by blocking 5-HT4 receptors with high doses (1 and 3 mg/kg, i.v.) of ICS 205-930. On the other hand, blocking 5-HT3 receptors with MDL 72222 (0.5 and 5 mg/kg, i.v.) or low doses (0.01 mg/kg i.v.) of ICS 205-930 had no apparent effect on the vomiting induced by copper sulfate. Oral administration of a 5-HT4 receptor agonist, 5-methoxytryptamine (5-MT), caused vomiting at a dose of 100 mg/kg, and the vomiting was inhibited markedly by abdominal visceral nerve section or a high dose (1 mg/kg, i.v.), but not a low dose (0.01 mg/kg, i.v.), of ICS 205-930. Intravenous administration of 5-MT (10 mg/kg) failed to induce vomiting. These results suggest that the abdominal visceral afferent fibers and possibly peripheral 5-HT4 receptors play an important role in the vomiting induced by oral administration of copper sulfate in dogs.

M13 bacteriophage DNA inhibits duck hepatitis B virus during acute infection

We investigated effects of various DNAs on duck hepatitis B virus replication in vivo. One-day-old ducks were infected intravenously with DHBV. Various DNAs were then injected intravenously, and duck hepatitis B virus levels were followed for up to 20 days after the inoculation. When M13 bacteriophage DNA (M13 DNA), heat-denatured Escherichia coli DNA or phi X 174 phage DNA was injected intravenously at a dose of 2.45 mg/kg body wt daily for 10 days, a significant decrease of serum duck hepatitis B virus DNA was detected within 10 days. The efficacy was twice that reported with antisense DNA on a weight basis and far more than that reported on a molar basis. M13 DNA was superior, on the basis of effective dose, to acyclovir as an anti-duck hepatitis B virus agent. On treatment with M13 DNA, serum 2-5 A synthetase level was increased five to six times, suggesting that the antiviral effect of M13 DNA is at least partly due to induction of endogenous interferon, which in turn induces 2-5 A synthetase. No significant inhibitory effect on replication of duck hepatitis B virus was demonstrated by DNAs obtained from herring testes, herring sperm, salmon testes, human placenta or calf thymus. On discontinuation of M13 DNA injection on day 10, duck hepatitis B virus reappeared in the serum at later time points. Digestion of M13 DNA with S1 nuclease resulted in marked reduction of antiviral activity. These results show that M13 DNA, not its digested product, has potent antiviral activity.

[Alteration of gamma-aminobutyric acid in streptozotocin-induced diabetic rat retina]

To elucidate possible alteration of gamma-aminobutyric acid (GABA) in the diabetic retina, the distribution and determination of GABA was analyzed in streptozotocin-induced diabetic and normal rats after electroretinogram (ERG) recording. Immunoreactivity of GABA was found in the inner nuclear layer, inner plexiform layer, and ganglion cell layer in normal and diabetic rats. In the inner nuclear layer, strong immunoreactivity of GABA was found in amacrine-like cells. In diabetic retinas, GABA immunoreactivity was higher than in normal retinas. The contents of GABA increased began 1 week after occurrence of diabetes mellitus, attained a maximum at 2 months, and maintained this amount for 5 months. The latencies of oscillatory potentials of ERG were prolonged beginning 1 month after occurrence. These results suggest that increase of GABA in the amacrine cells of diabetic retinas may be related with the abnormality of oscillatory potentials.

Possible involvement of central cholinergic system in ameliorating effects of indeloxazine, a cerebral activator, on disturbance of learning behavior in rats

Effects of indeloxazine, a cerebral activator, on passive avoidance learning by disruption of cholinergic transmission were studied in rats. The shortened latency was prolonged when indeloxazine was administered before training in rats subjected to scopolamine-injection, ethylcholine aziridinium ion (AF64A)-treatment and nucleus basalis magnocellularis (NBM) lesion. Indeloxazine administered immediately after training also showed ameliorating effects on passive avoidance in NBM-lesioned rats. Indeloxazine increased extracellular acetylcholine concentration in the frontal cortex of rats. Indeloxazine possesses facilitatory effects on cerebral function in part due to activation of the central cholinergic system.

Immunosuppression by a neutral thiol protease from parasitic helminth larvae in mice

The composition and immunological suppression of a novel proteinaceous material, a neutral thiol protease (NTP), isolated from the metacercaria of the helminth Paragonimus westermani are reported. From cDNA cloning and sequencing, the protease was found to be composed of 215 amino acid residues and closely resembled the known cysteine proteases. Treatment of adult mice with the enzyme suppressed the delayed footpad reaction and haemagglutinin antibody production, and reduced expression of the major histocompatibility complex and interleukin 2 receptor on lymphocytes, and induced suppressor cells in the spleen. In addition, stable and long-term skin graft survival was achieved by concomitant administration of the enzyme at a low dose.

The T-cell antigen CD5 acts as a receptor and substrate for the protein-tyrosine kinase p56lck

CD5 is a T-cell-specific antigen which binds to the B-cell antigen CD72 and acts as a coreceptor in the stimulation of T-cell growth. CD5 associates with the T-cell receptor zeta chain (TcR zeta)/CD3 complex and is rapidly phosphosphorylated on tyrosine residues as a result of TcR zeta/CD3 ligation. However, despite this, the mechanism by which CD5 generates intracellular signals is unclear. In this study, we demonstrate that CD5 is coupled to the protein-tyrosine kinase p56lck and can act as a substrate for p56lck. Coexpression of CD5 with p56lck in the baculovirus expression system resulted in the phosphorylation of CD5 on tyrosine residues. Further, anti-CD5 and anti-p56lck coprecipitated each other in a variety of detergents, including Nonidet P-40 and Triton X-100. Anti-CD5 also precipitated the kinase from various T cells irrespective of the expression of TcR zeta/CD3 or CD4. No binding between p59fyn(T) and CD5 was detected in T cells. The binding of p56lck to CD5 induced a 10- to 15-fold increase in p56lck catalytic activity, as measured by in vitro kinase analysis. In vivo labelling with 32P(i) also showed a four- to fivefold increase in Y-394 occupancy in p56lck when associated with CD5. The use of glutathione S-transferase-Lck fusion proteins in precipitation analysis showed that the SH2 domain of p56lck could recognize CD5 as expressed in the baculovirus expression system. CD5 interaction with p56lck represents a novel variant of a receptor-kinase complex in which receptor can also serve as substrate. The CD5-p56lck interaction is likely to play roles in T-cell signalling and T-B collaboration.

[A case of intracranial arteriovenous malformation presenting with intracranial hypertension]

A case of unruptured arteriovenous malformations (AVMs) presenting benign intracranial hypertension is reported. A 14-year-old male suffered from headache and papilledema. Intracranial pressure was 260 mmH2O. Unenhanced CT demonstrated no evidence of hemorrhage or hydrocephalus. Angiogram demonstrated a large AVM in the left temporal lobe supplied by the left posterior cerebral artery and left middle cerebral artery. It drained into the transverse sinus. Surgical excision of the AVM eliminated the headache and papilledema. AVM causes hemorrhage in 50% of cases, seizure in 30%, and other focal neurological deficits in 20%. Benign intracranial hypertension is an uncommon effect of unruptured AVMs. Only 13 cases have been reported in the literature. Benign intracranial hypertension associated with unruptured AVMs occurs in young patients with high flow AVMs that drain into the major sinus. The mechanism of intracranial hypertension associated with unruptured AVM is unknown. However, there are several possible mechanisms of intracranial hypertension associated with unruptured AVMs. The arterial blood shunting into a major sinus impedes venous return from the surrounding brain. That causes the increase of cerebral blood volume and the elevation of sinus pressure. This mechanism would reduce CSF absorption and would increase intracranial pressure. Pharmacological therapy is ineffective in controlling intracranial hypertension. Surgical excision of AVM effectively reduced intracranial hypertension. Thus, surgical excision of AVMs, if it can be done with low risk, is the treatment of choice to decrease intracranial hypertension in patients with unruptured cerebral AVMs.

Magnesium regulates ion transport across canine tracheal epithelium

We examined the effect of Mg2+ on potential difference (PD) and short circuit current (SCC) of the posterior epithelial membrane of canine trachea using an Ussing chamber. After the exchange to a Mg(2+)-free solution, PD and SCC rapidly increased, reaching maximal values within 3 min, followed by a gradual return towards the baseline over 60 min. In a Ca(2+)-free solution, Mg2+ removal did not alter PD and SCC values. Increased Mg2+ in the solution produced significant gradual decreases in PD and SCC. The decreases in PD and SCC were reversed by the addition of excessive Ca2+ to the solution. Mg2+ removal did not alter significantly isoproterenol-induced increases in PD and SCC values, while increased Mg2+ significantly reduced the increases. These findings indicate that extracellular Mg2+ is an important determinant in ion transport across the airway epithelium, probably through antagonistic actions of Mg2+ and Ca2+.

Respiratory load compensation during hypercapnic ventilatory response in pulmonary emphysema

The purpose of this study is to examine the relationship between mechanical factors and the load compensation during hypercapnia in emphysema. In 36 clinically stable patients, we conducted pulmonary function tests and hypercapnic ventilatory response (HCVR) tests with and without inspiratory flow-resistive loading (IRL) (17 cm H2O/L/s). The mean value of HCVR significantly decreased with IRL, while that of the mouth occlusion pressure (P0.1) response increased. Regardless of IRL, the HCVR values were correlated with FEV1/FVC and airway resistance. The load compensation, evaluated by the ratio of the HCVR value and the P0.1 response before and after IRL, was inversely correlated with percent FRC (r = -0.38, r = -0.39; both p < 0.05). Breathing pattern analysis at the end-tidal pressure of carbon dioxide of 55 mm Hg elicited the decrease of (tidal volume/inspiratory time (VT/TI) and the increase of TI and TI/TTOT. Although the absolute changes of VT and f were inconsistent among subjects, each relative ratio before and after IRL was correlated again with percent FRC (r = -0.46, r = 0.44: both p < 0.01). Therefore, the position of the inspiratory muscles at the onset of inspiration may influence the load compensation during hypercapnia in emphysema.

Development and characterization of macrophage hybridomas derived from murine peritoneal exudate cells

Mouse macrophage (Mphi) hybridoma clones were generated by somatic cell hybridization of myeloma X63 cells (H-2d) with C57BL/6 (H-2b) peritoneal exudate cells elicited with a streptococcal preparation, OK432, or thioglycollate medium. Although they hardly adhered to plastic dishes and could not be morphologically distinguished from parental X63 tumor cells, the clones retained Mphi characteristics. These included phagocytosis and production of lysozyme and nonspecific esterase, suggesting that they were hybridomas derived from Mphi. Some of them expressed various levels of Ia antigen and Fc receptor. Because they induced proliferation of T cells from Balb/c mice but not those from C57BL/6 mice, the Ia antigen of Mphi hybridoma was assumed to be derived from peritoneal Mphi. The level of proliferation induction was correlated to the level of Ia antigen expression. Several clones produced a factor that cytostatically inhibited growth of murine mammary carcinoma and was serologically identified with arginine deiminase.

Growth regulation in primary culture of rabbit arterial smooth muscle cells by platelet-derived growth factor, insulin-like growth factor-I, and epidermal growth factor

Many studies have linked the proliferation of smooth muscle cells (SMC) to the development of atherosclerotic lesions. We examined the effects of platelet-derived growth factor (PDGF), insulin-like growth factor-I (IGF-I), and epidermal growth factor (EGF) on the regulation of SMC grown on type I collagen-coated dishes in serum-free primary culture. When added alone, PDGF (10 ng/ml), IGF-I (20 ng/ml), and EGF (10 ng/ml) produced minimal effects on BrdU (5-bromo-2'-deoxyuridine) incorporation into cellular DNA and on cell growth. However, simultaneous addition of PDGF and IGF-I significantly stimulated DNA synthesis and cell growth. The combination of PDGF, IGF-I, and EGF synergistically stimulated DNA synthesis and cell proliferation. Flow cytometric analysis indicated that type I collagen alone promoted the phenotypic modulation and progression of the cells from the G0 (contractile phenotype) to the G1A phase (intermediate phenotype), PDGF and IGF-I, together, stimulated the rate of cell transition from the G1A to the G1B and S phases (synthetic phenotype), and PDGF, IGF-I, and EGF together stimulated the rate of cell transition into the S and G2+ M phases. In contrast, in quiescent secondary cultured SMC (G1B phase), PDGF alone was able to initiate DNA synthesis, although IGF-I and EGF were required to complete DNA synthesis. These results reveal that PDGF and IGF-I stimulate the cells to complete the G1A phase and proceed to the G1B phase and that EGF regulates the rate of entry into the S phase in rabbit SMC in primary culture. Furthermore, differences in the responsiveness to these growth factors between primary and secondary cultures reflected the varying phenotypic properties of vascular SMC.

Differential effects of chronic L-dopa treatment on lipid peroxidation in the mouse brain with or without pretreatment with 6-hydroxydopamine

Whether or not chronic L-dopa treatment (100 mg/kg, intraperitoneally (i.p.), twice daily for 4 weeks) alters lipid peroxidation in the brain as an indicator of neuronal damage was examined in normal mice and mice in which catecholamine (CA) neurons had been injured previously by the administration of 6-hydroxydopamine (6-OHDA), followed by recovery. In normal mice, chronic L-dopa treatment reduced the thiobarbituric acid reacting substances (TBARS) level, an indicator of lipid peroxidation, in the cerebral cortex. In contrast, in mice with CA neuronal injury induced by pretreatment with 6-OHDA, the chronic L-dopa treatment markedly increased the TBARS in the striatum and frontal cortex, despite recovery of the striatal dopamine levels similar to those in the control mice. These findings suggest that the long-term high-dose administration of L-dopa enhances the progression of neuronal damage in patients with injured CA neurons such as those with Parkinson's disease.

Structure and regulation of the chicken erythroid delta-aminolevulinate synthase gene

Erythroid cells regulate heme biosynthesis in a manner that is distinct from all other cell types. While heme negatively regulates the synthesis of the housekeeping delta-aminolevulinate synthase (ALAS-N) in all non-erythroid cells, the expression of an erythroid-specific isozyme (ALAS-E) is developmentally regulated in red blood cells. As a first step towards understanding the molecular basis for the transcriptional regulation of ALAS-E during erythropoiesis, we cloned and characterized the chicken ALAS-E locus. This gene spans 18 kbp and is composed of eleven exons. The intron/exon structure of erythroid ALAS was found to be conserved among several vertebrate species. Direct RNA sequencing identified a 5' untranslated region that is derived from two continuous exons and is predicted to form a very stable stem-loop structure that bears resemblance to the ferritin iron-responsive element. Tissue-specific expression of the ALAS-E gene was analyzed by transient transfection assays in hematopoietic cells of both erythroid and non-erythroid origins. These experiments identified distal (-784 to -505 bp) and proximal (-155 to +21 bp) promoter elements which are required for high level, erythroid-specific transcription.

[Angiomyolipoma of the anterior mediastinum--a case report]

An asymptomatic 22-year-old female showed an enlarged mediastinal shadow in a chest X-ray mass screening. Computed tomogram indicated a tumor with a CT-number of 7-8 in her left anterior mediastinum, adjacent to the pericardium. With MRI the tumor showed a low signal intensity of T1 weighted images and a high signal intensity of T2 weighted images. Thoracotomy revealed that the tumor was yellow-whitish, and had a size of 7 x 7 x 1 cm. It was histologically composed of fatty tissue, smooth muscle, and vascular tissue, and was diagnosed as angiomyolipoma. Although angiomyolipomas are often found in the kidney, they are very rare in the mediastinum and difficult to diagnose by image analysis.

Temporal and spatial changes in GATA transcription factor expression are coincident with development of the chicken optic tectum

The molecular mechanisms specifying patterns of gene expression in the vertebrate brain, which in turn determine the developmental fates of specific neurons, are yet to be clearly defined. Individual members of a recently identified family of transcriptional regulatory proteins, the GATA factors, are required for the differentiation of certain hematopoietic cell lineages. We show here that two of the members of this gene family, GATA-2 and GATA-3, are expressed within discrete cell populations of the chicken optic tectum during embryogenesis, and that they have highly restricted patterns of expression in the developing chicken brain. Furthermore, the induction of GATA factor expression within specific cell layers parallels the well established spatial (rostral to caudal) and temporal pattern of optic tectum development. The observation that both the timing of appearance and the localization of expression of GATA-2 and GATA-3 are correlated with optic tectum development suggest that these transcription factors may be associated with the initiation of gene transcription required for the determination of specific neuronal fates within visual areas of the vertebrate brain.

Effect of maternal paraquat administration on the fetal ductus arteriosus in the rat

The ductus arteriosus (DA) in the fetal rat was calibrated using a whole-body freezing method, 3 hr after maternal treatment with paraquat at a dose of 25 mg/kg of body weight on days 19-21 of gestation. On days 20 and 21, the DA was significantly constricted. The DA was also significantly constricted on day 19 2/3 but not on day 19 1/2. It is concluded that paraquat has a constrictive effect on the DA and that the onset of this effect occurs in the first half of day 19 of gestation.

[Genetic characteristics of Japanese pedigrees with Leber's hereditary optic neuropathy]

Although point mutation at nucleotide position 11778 of mitochondrial (mt) DNA is associated with Leber's hereditary optic neuropathy (LHON), the existence of the mutation alone is not sufficient for LHON expression. Whether the mutation is homo- or heteroplasmic, or whether secondary mutations additionally exist did not explain intra- or interfamilial phenotypic variations in at least 10 Japanese pedigrees tested. Segregation analysis showed that both mtDNA mutation and abnormal X-linked gene (XLG) are necessary for development of optic atrophy, and that an unfortunate X-inactivation is involved. The frequency of the presumed abnormal XLG and its penetrance are estimated to be about 0.1 and 0.2, respectively. The latter value is about twice as high as the value for Caucasian pedigrees. This evidence suggests a relatively homogeneous mtDNA abnormality and a low disease threshold derived from the XLG abnormality in female offsprings in Japanese LHON maternal lines.

Amplification of N-myc gene and increase of urinary VMA and HVA in patients with neuroblastic tumors

Neuroblastic tumor cases in our departments were evaluated in terms of the stage of the tumor, N-myc amplification, urinary vanillylamndelic acid (VMA)/homovanillic acid (HVA) and survival rate. Two asymptomatic cases, diagnosed when under a year old by mass screening, had no amplifications of N-myc but showed more than one value of urinary VMA/HVA ratio. The patients are now doing well eight years after complete excision of the neuroblastoma which had originated in the sympathetic ganglion. On the other hand, two other symptomatic cases, operated on at the ages of 3 and 5 years, showed remarkable amplifications with less than one value of urinary VMA/HVA, and died from the tumor soon after partial resection of the neuroblastoma and ganglioneuroblastoma which had originated in the adrenal gland and the sympathetic ganglion, respectively. The present monograph reports our cases and discusses prognostic factors.