Repulsive contribution of surface sialic acid residues to cell adhesion to substratum

Roles of surface sialic acid residues in cell adhesion to substratum were investigated in model systems to clarify their contribution to intercellular interactions. Treatment of cells of a fibroblastic cell line, Swiss 3T3, an epithelial cell line, TES-1, and a T lymphoma cell line, BW5147, with a sialylated oligosaccharide binding lectin enhanced adhesion to plastic plates irrespective of the cell lineage. This enhancement was inhibited by the addition of sialyl lactose. Digestion of the cells with sialidase or endoglycoceramidase also augmented adhesion. On the other hand, adhesion was reduced by pre-coating plastic plates with gangliosides but not with desialylated gangliosides. These findings suggest that sialic acid residues exposed to cell surfaces negatively regulate cell adhesiveness.

Novel mutations in the V2 vasopressin receptor gene in two pedigrees with congenital nephrogenic diabetes insipidus

Novel mutations in the V2 vasopressin receptor gene were identified in two Japanese pedigrees with X-linked congenital nephrogenic diabetes insipidus. The V2 receptor belongs to the family of G-protein-coupled receptors that contain seven distinct transmembrane domains, and the V2 receptor gene is encoded by three exons. The coding regions amplified by polymerase chain reaction were directly sequenced. In a pedigree, one of four consecutive guanine sequences (nucleotides 528-531) in the second exon was deleted (528delG). This deletion mutation results in a frame shift beginning at codon 154 in the second intracellular domain and a premature termination at codon 161. In another pedigree, a missense mutation (A-->G) was identified at nucleotide position 310 in the second exon. This point mutation, H80R, changes a histidine at codon 80 in the second transmembrane domain to an arginine that is more positively charged than histidine under the neutral environment. Each mutation cosegregated with the phenotype of diabetes insipidus and supposed to be a cause for resistance to arginine vasopressin.

Two cases of asymptomatic adrenocortical insufficiency with autoimmune thyroid disease

Two cases of asymptomatic adrenocortical insufficiency are reported. Both patients had a normal cortisol and increased ACTH. The cortisol response to ACTH was impaired, although not absent, in both cases. One case was associated with autoimmune polyglandular syndrome type II (Graves' disease and vitiligo), and the other was possibly associated with an early stage of Hashimoto's thyroiditis, suggesting autoimmune pathogenesis of their adrenocortical insufficiency. CT of the abdomen revealed unilateral enlargement of the adrenal glands in one case, but no enlargement of the adrenal glands in another case. Adrenal hypofunction seemed to be compensated for by increased trophic hormone (ACTH), as in subclinical hypothyroidism. However, prolonged ACTH stimulation increased urinary 17-OHCS in both cases, and normalized cortisol response to ACTH in one case. In both cases, the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were normal, and adrenal autoantibodies were negative, suggesting that neither negative adrenal autoantibodies nor normal PRA can exclude asymptomatic adrenocortical insufficiency. The results suggest that a rapid ACTH test should be performed in cases with increased ACTH, especially those associated with other autoimmune endocrine disorders.

Glibenclamide enhances but pinacidil reduces attenuation in sympathetic responsiveness after acute coronary artery occlusion

To investigate the role of ATP-sensitive K+ channels in modulating the efferent autonomic response following acute myocardial ischemia/infarction, we examined the effects of a blocker (glibenclamide) and an opener (pinacidil) of ATP-sensitive K+ channels on the time course and extent of the attenuation in efferent cardiac sympathetic responsiveness in anesthetized dogs. We measured the effective refractory periods (ERPs) at nonischemic sites basal and apical to the area of myocardial ischemia/infarction in the baseline state and during bilateral stimulation of the ansae subclaviae before and after each drug administration and 5, 30, 60, 120, and 180 minutes after latex injection of a diagonal branch of the left anterior descending coronary artery. Animals received either vehicle (n = 12), glibenclamide (0.3 mg.kg-1, n = 10), pinacidil (0.15 mg.kg-1 + 0.2 mg.kg-1 infusion, n = 10), or a combination of these two drugs (n = 9) intravenously. In another group of dogs receiving just pinacidil (n = 10), an intra-aortic balloon was inflated distal to the renal arteries to prevent pinacidil-induced hypotension. Another group of dogs received either high-dose glibenclamide (0.3 mg.kg-1 + 0.15 mg.kg-1, n = 4), low-dose glibenclamide (0.06 mg.kg-1, n = 4), medium-dose pinacidil (0.03 mg.kg-1 + 0.04 mg.kg-1 infusion, n = 4), or low-dose pinacidil (0.0075 mg.kg-1 + 0.01 mg.kg-1 infusion, n = 4). In all dogs, basal sites exhibited no attenuation of sympathetically induced shortening of the ERP throughout the period of acute myocardial ischemia/infarction. Cumulative attenuation in sympathetic responsiveness (shortening of ERP < or = 2 milliseconds induced by bilateral stimulation of the ansae subclaviae) at nonischemic test sites apical to the area of ischemia/infarction during a 3-hour period was greater in the glibenclamide group (26 of 44 sites, P = .008) and less in the pinacidil (2 of 44 sites, P = .002) and pinacidil-balloon (1 of 48 sites, P < .001) groups compared with the vehicle group (14 of 46 sites). Glibenclamide abolished the protective effect of pinacidil so that 10 of 45 sites had < 2-millisecond shortening during a 3-hour period in the glibenclamide + pinacidil group (P = .018 versus pinacidil group, P = .286 versus vehicle group). Such effects of glibenclamide and pinacidil on sympathetic attenuation were dose dependent. Maintaining the blood glucose level during glibenclamide administration did not affect the sympathetic attenuation after acute coronary artery occlusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Gastrin receptor gene expression in several human carcinomas

Gastrin has been shown to enhance the growth of various human tumors. The present study was designed to examine the gastrin receptor gene expression in various human carcinoma cell lines and in surgically resected carcinoma tissues. By Northern blot analysis, gastrin receptor mRNA was detected in 3 out of 7 small cell lung carcinoma cell lines. Gastrin receptor mRNA was also expressed in one out of 8 colon carcinoma cell lines and 2 out of 10 colon carcinoma tissues. Moreover, one of two small cell carcinoma cell lines of the stomach clearly expressed gastrin receptor mRNA. However, none of the gastric adenocarcinoma cell lines or surgically resected gastric adenocarcinomas tested had any detectable expression of gastrin receptor gene. These findings may suggest a role of gastrin receptor in the growth and differentiation of certain human carcinomas.

Isolated congenital left ventricular diverticulum in an adult. A case report

A sixty-three-year-old man presented himself with atrial flutter and congestive heart failure. Cardiac catheterization revealed that left ventricular diverticulum was located on the anterobasal wall with narrow connection to the left ventricular cavity. Coronary angiography revealed normal coronary arteries. The patient had been asymptomatic until adult life with no other thoracoabdominal or cardiac anomalies. This is an extremely rare finding in the adult population.

Vertebral measurements for assessment of osteoporosis

We measured the vertebral heights and spinal bone mineral density (BMD) of healthy women, and morphometrically evaluated the physiological features of the vertebrae to investigate the relationship of BMD to types of spinal deformity as well as the radiographic detection rate for decreased vertebral bone density. Vertebral BMD was measured from L1 to L4 using dual X-ray absorptiometry and from L1 to L3 using quantitative computed tomography in 245 healthy women ranging in age from 22 to 81 years. The vertebral heights, anterior (Ha), middle (Hm), and posterior (Hp), were measured from T12 through L5, and the Ha/Hp and Hm/Hp ratios were calculated. Although the age-related reduction of vertebral height was not as marked as that of BMD, the vertebral heights, especially the Ha and Hm from T12 to L5 vertebrae, and the Ha/Hp and Hm/Hp from T12 to L3, significantly decreased with age. The presence of a wedge-shaped deformity was strongly related to cortical BMD, and biconcave deformity to trabecular BMD. Although investigation of the sensitivity and specificity of several criteria revealed that vertebra-specific dimension criteria are useful in the detection of decreased bone density, the detection of decreased BMD using vertebral measurements is considered to be limited.

Intravascular treatment of spinal arteriovenous malformations using a microcatheter--with special reference to serial xylocaine tests and intravascular pressure monitoring

Spinal arteriovenous malformations (spinal AVMs) are now treated using microcatheters and various embolic materials. Interventional techniques of this type are thought to be the first choice for treatment of spinal AVMs. In this study, we used the Tracker vascular access system and MAGIC catheter for intravascular treatment of spinal AVMs in order to avoid proximal occlusion. Notably, serial provocation tests using xylocaine (20 mg in bolus) and intermittent intravascular pressure monitoring in the anterior spinal artery were conducted during embolizations of five intramedullary AVMs. We used 150-350 microns polyvinyl alcohol particles (Ivalon) and/or polyvinyl alcohol (PVA) solutions as embolic materials for occlusion of these AVMs. Vital signs and neurologic functions were carefully monitored during and after the procedure. We were able totally to obliterate the nidus or markedly to reduce its size while preserving the anterior spinal artery in each of the patients. The xylocaine test was conducted an average of 2.6 times (2-4 times) during embolization. For the two patients who were treated with Ivalon and PVA solutions, the final provocation test became positive, and the embolization procedure was terminated. On the other hand, the remaining patients had a positive result on first xylocaine test and were treated with Ivalon alone. At the same time, intravascular pressure monitoring was performed via the microcatheter, which was located in the anterior spinal artery. The value of the intravascular systolic pressure prior to embolization was 71.6 +/- 14.1 mm Hg and it gradually increased during the procedure, and reached 99.6 +/- 12.6 mm Hg (90% of the systemic systolic blood pressure) by the conclusion of embolization. Serial xylocaine tests and intravascular pressure monitoring may be useful for the treatment of spinal AVMs fed mainly by the anterior spinal artery, and embolization with liquid embolic material should be terminated when the provocation test becomes positive and intravascular pressure increased to 90% of the systemic blood pressure.

Anti-inflammatory effects of recombinant human manganese superoxide dismutase on adjuvant arthritis in rats

The anti-inflammatory effects of recombinant human manganese superoxide dismutase on adjuvant arthritis was investigated. Local application of this manganese superoxide dismutase given every 2 days not only significantly reduced foot swelling but also retarded radiological bone destruction in adjuvant arthritis. Copper zinc superoxide dismutase had little effect on foot swelling.

Effect of varicella zoster virus antigen-antibody complexes on hydrogen peroxide generation by human polymorphonuclear leukocytes

Hydrogen peroxide (H2O2) generation by human polymorphonuclear leukocytes (PMN) incubated with varicella zoster virus (VZV) antigen was studied by cytofluorography. Hydrogen peroxide generation was detected in the presence of VZV-seropositive sera. When seropositive sera were heat-inactivated, H2O2 generation was reduced. When PMN were pre-incubated with Leu-11b, a monoclonal antibody to the Fc receptor on PMN, H2O2 generation was also reduced. These results suggest that VZV antigen-antibody-complement complexes induce H2O2 generation by PMN after these complexes attach to Fc receptors on PMN.

Tropomodulin in rat cardiac muscle. Localization of protein is independent of messenger RNA distribution during myofibrillar development

Tropomodulin is a 40.6-kD protein that colocalizes with actin filament pointed ends in skeletal muscle. We report the sequence of two partial-length complementary DNA (cDNA) clones of rat cardiac tropomodulin that cover 90% of the coding region. The cDNA sequence is 90% conserved between human and rat, with the predicted amino acid sequence similarity even higher at 95%. Anti-tropomodulin antibodies label a single polypeptide with an apparent mobility of 43,000 in Western blot analysis of rat cardiac muscle. Immunofluorescence experiments using this anti-tropomodulin antibody result in labeling that is coincident with thin filament ends, as demonstrated by double localization with alpha-actinin antibody. Tropomodulin protein is organized into a sarcomeric staining pattern with the earliest appearance of myofibrils in rat cardiocytes. The localization of tropomodulin protein at or near thin filament ends led us to examine the distribution of tropomodulin messenger RNA (mRNA) during myofibrillar development in vitro. Fluorescent in situ hybridization experiments using tropomodulin cDNA probe in cardiocytes that have been cultured for 3 to 5 days show a distribution of large mRNA patches. The cytoplasmic location of tropomodulin mRNA at this time, which bears no relation to the developed myofibrils, suggests that tropomodulin protein is targeted to thin filament ends rather than using localized translational machinery. However, the distribution of tropomodulin mRNA in cultured cardiocytes changes over the next 2 weeks from large perinuclear patches to small concentrations arranged along myofibrils throughout the cell. The reorganization of tropomodulin mRNA throughout the cardiocyte appears to be distinct from the pattern of glyceraldehyde-3-phosphate dehydrogenase mRNA within the same time period. Increasing intracellular density of myofibrils within developing cardiocytes may lead to redistribution of selected mRNAs for localized translation.

Endoglycoceramidase treatment inhibits synchronous oscillations of intracellular Ca2+ in cultured cortical neurons

Gangliosides are major components of nerve cell membranes and are especially rich in synaptic areas. In order to evaluate the role of endogenous gangliosides in synapse formation, endoglycoceramidase (EGCase) was used to remove oligosaccharides of gangliosides from the cell surface. We have reported previously that synapse formation between cultured rat cerebral cortical neurons can be estimated by the synchronous oscillation of synaptic activity monitored by fura-2 calcium imaging. Continuous application of endoglycoceramidase (EGCase) together with its activator protein dose-dependently decreased the frequency of synchronous oscillations without any morphological changes in neurons and their neurites. The result suggests that oligosaccharides liberated from glycosphingolipids on cultured cortical cell surface with EGCase are important for synapse formation between cortical neurons.

Effect of DP-1904, a thromboxane A2 synthetase inhibitor, on crescentic nephritis in rats

The antinephritic effect of DP-1904 [6-(1-imidazolylmethyl)-5,6,7,8-tetrahydronaphthalene-2-carboxylic acid hydrochloride], a thromboxane A2 synthetase inhibitor, was compared with that of OKY-046, using an experimental model of nephritis, crescentic-type anti-glomerular basement membrane nephritis. Test drugs were given p.o. once daily from the day after the the development of glomerular alteration as well as the elevation of proteinuria and plasma cholesterol. On the other hand, OKY-046 (20 mg/kg per day), a thromboxane A2 synthetase inhibitor, significantly inhibited only deterioration in the glomeruli. DP-1904 and OKY-046 inhibited glomerular thromboxane B2 production and increased glomerular prostaglandin E2 and 6-keto prostaglandin F1 alpha production in normal and nephritic rats. Both drugs inhibited the increase in platelet aggregability, restored decreased renal tissue blood flow to a near-normal level and decreased the deposition of rat immunoglobulin G on glomerular basement membrane in nephritic rats. These results suggest that DP-1904 may be an effective agent for the treatment of proliferative glomerulonephritis.

Urate oxidase is imported into peroxisomes recognizing the C-terminal SKL motif of proteins

Rat liver urate oxidase synthesized from cDNA through coupled transcription and translation was incubated at 26 degrees C for 60 min with purified peroxisomes from rat liver. Urate oxidase was efficiently imported into the peroxisomes, as determined by resistance to externally added proteinase K. The amount of imported urate oxidase increased with time and the import was temperature dependent. A synthetic peptide composed of the C-terminal 10 amino acid residues of acyl-CoA oxidase (the C-terminal tripeptide is Ser-Lys-Leu) inhibited the import of urate oxidase, whereas other peptides, in which the C-terminal Ser-Lys-Leu (SKL) sequence was deleted or mutated, were not effective. Two mutant urate oxidase proteins in which the C-terminal Ser-Arg-Leu (SRL) sequence was deleted or mutated to Ser-Glu-Leu (SEL) were not imported into peroxisomes. With substitution of a lysine residue for arginine in the SRL tripeptide at the C-terminus the import activity was retained. These results show that urate oxidase is important into peroxisomes via a common pathway with acyl-CoA oxidase, and that the C-terminal SRL sequence functions as a peroxisomal-targeting signal.

Multicentric glioma studied with positron emission tomography: a case report

Positron emission tomography (PET) studies of a multicentric glioma case were undertaken using 11C-methionine (Met) and 18F-fluorodeoxyuridine (FUdR). Met-PET revealed high accumulating lesion in both the left and right hemispheres, whereas in the FUdR-PET, the lesion on the right showed marked accumulation, but not that on the left. For both foci, the histologic diagnoses were anaplastic astrocytoma, but the lesion on the right showed higher density of undifferentiated tumor cells than that on the left. PET studies using Met and FUdR are effective in delineating the proliferative potential of glioma cells, which otherwise cannot be determined by histopathologic studies.

Impaired cell-mediated immunity to cytomegalovirus (CMV) in leukemic children with prolonged CMV viruria

To determine the role of cell-mediated immunity (CMI) to cytomegalovirus (CMV) in leukemic children after CMV infection, CMI to CMV antigen was studied using CMV-specific lymphocyte blastogenic responses (LBR) and interferon (IFN) production. Four children, who continuously secreted CMV in urine more than 2 years after symptomatic CMV infection (CMV disease) (group 1), showed impaired LBR to CMV antigen, though they had normal LBR to phytohemagglutinin (PHA) and concanavalin A (Con A). Impairment of LBR either to AD-169 strains or autologous and heterologous wild strains was observed. IFN production was not detected in three of four children. Six leukemic children, who had no viruria after cessation of CMV disease (group 2), showed good responses to CMV antigens. IFN was detected in all six children in group 2. Eight leukemic children, who were seropositive to CMV at the onset of leukemia (group 3), showed good responses to CMV antigens and IFN production. These results suggest that impaired cell-mediated immunity to CMV antigen might contribute to prolonged excretion of CMV in urine in leukemic children.

TGF-beta-induced macrophage colony-stimulating factor gene expression in various mesenchymal cell lines

We report here that transforming growth factor-beta (TGF-beta) can increase the expression level of macrophage colony-stimulating factor (M-CSF) mRNA in a variety of mesenchymal cell lines derived from osteoblasts, bone marrow stromal cells, fibroblasts, and myoblasts. The M-CSF activity in the conditioned medium of mouse osteoblast-like MC3T3-E1 cells was increased by TGF-beta as well as interleukin-1 (IL-1) treatment. The increase of M-CSF mRNA expression was observed as early as 2 h after TGF-beta or IL-1 addition and was superinduced by cycloheximide treatment. Nuclear run-off assays revealed that the increase in M-CSF mRNA by TGF-beta as well as IL-1 occurred, at least in part, at the transcriptional level. Platelet-derived growth factor (PDGF) also enhanced the M-CSF production in MC3T3-E1 cells. Furthermore, TGF-beta and IL-1 distinctly induced both PDGF-A and PDGF-B chain mRNA in MC3T3-E1 with different time courses. Our present studies suggest that PDGF autocrine loop-dependent and loop-independent pathways could modulate the M-CSF production stimulated by TGF-beta or IL-1 and account for the complexity of the cytokine network involving M-CSF in vivo under various physiological and pathological conditions.