Schwann cell responses to forskolin and cyclic AMP analogues: comparative study of mouse and rat Schwann cells

Forskolin and cAMP analogues (8-bromo cAMP and dibutyryl cAMP) induced proliferation or surface galC expression, depending on the concentrations, in rat and mouse Schwann cells in vitro. However, rat Schwann cells required much higher concentrations of these agents than mouse Schwann cells in both proliferation and surface galC expression. The concentrations needed for cellular proliferation were 0.5 microM forskolin or 10 microM cAMP analogues in mice and 2.5 microM forskolin or 50 microM cAMP analogues in rats. Surface galC was expressed in mouse Schwann cells at concentrations of 10 microM forskolin or 100 microM cAMP analogues, while in rat Schwann cells, 50 microM forskolin or 500 microM cAMP analogues was needed for expression of surface galC. Rat Schwann cells transformed from an elongated spindle shape to flattened cells by the addition of these agents. However, mouse Schwann cells remained spindle shaped and their processes were apparently elongated at concentrations of more than 1.0 microM forskolin or 100 microM cAMP analogues. These results may reflect the differences in the cellular metabolism between mouse and rat cells. Moreover, the elongation of mouse Schwann cell processes appeared to be associated with surface galC expression, suggesting that elongation may be an initial signal for differentiation in mouse Schwann cells.

Up-regulation of dystrophin mRNA by exposure to dibutyryl cAMP in the C2C12 muscle cell line

The effect of dibutyryl cAMP on dystrophin mRNA expression was investigated in C2C12 myogenic cells by a semi-quantitative RT-PCR method. The dystrophin mRNA level was enhanced by the addition of low concentrations of dibutyryl cAMP for 16h in the growth medium. The relative amounts of dystrophin/G3PDH mRNA at 10(-4) M dibutyryl cAMP were about 2.6-fold higher compared to control. We examined MLC1a mRNA expression in order to know whether the induction of dystrophin mRNA is due to the facilitation of myogenic differentiation by dibutyryl cAMP. MLC1a mRNA expression at 10(-4) M dibutyryl cAMP was similar to that of control. Thus we conclude that the dibutyryl cAMP enhancement of dystrophin mRNA expression is not due to a secondary event involving the formation of differentiated myotubes. The induction of CREB mRNA by dibutyryl cAMP suggests that the up-regulation of dystrophin mRNA expression might occur via transcriptional activation.

Molecular cloning of a novel actin-binding protein, p57, with a WD repeat and a leucine zipper motif

A 57 kDa protein (p57) was obtained during the study on phosphatidylinositol-specific phospholipase C. Its cDNA was isolated from calf spleen and human leukemia cell line HL60 libraries and cloned. In the primary structures of p57, they have two unique amino acid sequence motifs, a WD repeat and a leucine zipper motif. Furthermore, p57 shared sequence similarity (40%) with coronin, an actin-binding protein responsible for chemotaxis, cell motility, and cytokinesis of Dictyostelium discoideum, which has only the WD repeat. p57 also showed an actin-binding activity and was mainly expressed in immune tissues. From these results, we conclude that p57 is a coronin-like novel actin-binding protein in mammalian cells but may also have a different function from coronin.

Okadaic acid induces both augmentation and inhibition of opsonized zymosan-stimulated superoxide production by differentiated HL-60 cells. Possible involvement of dephosphorylation of a cytosolic 21K protein in respiratory burst

We found that okadaic acid (OA), a potent tumor promoter and a phosphatase inhibitor, has a unique opposing effect on opsonized zymosan (Op.-zym.)-elicited O2.- production by differentiated HL-60 cells in a narrow range of concentrations but does not induce any O2.- production by itself. Okadaic acid magnified the O2.- production 2.5-fold at 1.0 microM, while it inhibited it at 2.0 microM or higher concentrations. This effect of OA did not correspond to the changes in the expression of surface receptors (CD11b/CD18, CR3) for Op.-zym., because they were weakly down-regulated by OA at any concentration. Two-dimensional gel electrophoresis revealed that in the absence of OA, Op.-zym. induced rapid dephosphorylation of a cytosolic 21K protein with a very slight increase in phosphorylation of membranous p47phox, which is one of the cytosolic factors required for respiratory burst. In the presence of a stimulatory concentration (1.0 microM) of OA, the Op.-zym.-caused dephosphorylation of the 21K protein was still observed and the phosphorylation of p47phox was enhanced. In the presence of an inhibitory concentration (2.0 or 5.0 microM) of OA, the Op.-zym.-induced dephosphorylation of the 21K protein was strongly inhibited while p47phox was heavily phosphorylated. Acid hydrolysis of the 21K phosphoprotein yielded only phosphoserine as a phosphoamino acid. Furthermore, at least part of the 21K protein seemed to be associated with p67phox and p47phox, because it was co-immunoprecipitated with those cytosolic factors. These results suggest that a cytosolic 21K protein plays an important role in respiratory burst through dephosphorylation by a phosphoserine phosphatase, and that the dephosphorylated 21K protein may work synergistically with the phosphorylated p47phox on the pathway for activation of the respiratory burst oxidase.

Conventional protein kinase C (PKC)-alpha and novel PKC epsilon, but not -delta, increase the secretion of an N-terminal fragment of Alzheimer's disease amyloid precursor protein from PKC cDNA transfected 3Y1 fibroblasts

A large soluble N-terminal fragment of Alzheimer's disease amyloid precursor protein (secreted form of APP: APPs) is produced by constitutive processing in the middle of the amyloid beta-protein portion of APP. Recent studies indicate that the activation of endogenous protein kinase C (PKC) with phorbol ester raises the rate of secretion of APPs. We constructed rat fibroblast 3Y1 cells that stably overexpress PKC isoenzymes alpha, delta, or epsilon, and analyzed the amount of APPs released from these PKC transfectants. The levels of APPs released from 3Y1 cells overexpressing PKC alpha and -epsilon were higher than those from PKC delta-transfected and control cells expressing vector only. These results suggest that specific isoforms of PKC regulate the secretion of APPs through a signaling pathway.

[Physiological significance of superoxide dismutase isozymes]

Superoxide dismutases (SODs) scavenge superoxide anion and participate in an essential role as a defense system against oxidative stress in body. Cu,Zn-SOD is localized at cytoplasm. A defect in the Cu,Zn-SOD gene has been demonstrated in some cases of familial amyotrophic lateral sclerosis. Trisomy of chromosome 21 in Down's syndrome increases the level of this isozyme and causes the disease. Inactivation of Cu,Zn-SOD by glycation under hyperglycemic conditions may also be a critical factor for diabetic complication. The expression of the second isozyme, Mn-SOD localized at mitochondrial matrix, is regulated in a complex manner by many stimulants such as interleukin-1, -6, tumor necrosis factor, lipopolysaccharide, and tumor promoters phorbol ester (TPA) and okadaic acid. This isozyme seems to work as a defense mechanism against damage during inflammatory responses. The third isozyme, extracellular SOD, is highly glycosylated and has affinity for heparin sulfate. This may participate in scavenging superoxide in plasma and, therefore, missense mutation in heparin binding domain increases the serum level of this isozyme, although the physiological role is not clearly understood yet.

[The effect of lactitol (NS-4) on the concentrations of ammonia and amino acids in blood and cerebrospinal fluid in Eck fistula (portacaval-shunted) dogs]

Lactitol and lactulose were compared in their effect on the concentrations of ammonia and amino acids in blood and cerebrospinal fluid (CSF) in Eck fistula dogs. Drugs were administered intragastrically for four weeks from three weeks after the portacaval-shunt operation. The concentration of ammonia in the blood and CSF had increased three- to five-fold three weeks after the operation and increased gradually thereafter. Eck fistula dogs showed a characteristic profile of plasma amino acids, with increased concentrations of tryptophan (Trp) and aromatic amino acids (AAA) and reduced concentrations of branched-chain amino acids. The profile of CSF amino acids revealed substantial increases in the concentrations of AAA as well as glutamine (Gln), Trp and glutamic acid. Lactitol at doses of 1 and 3 g/kg/day significantly decreased the ammonia concentration in both the blood and CSF after administration for two and four weeks. Lactitol at a dose of 3 g/kg/day significantly decreased the concentration of Trp in the plasma and the concentrations of valine, leucine, AAA and Gln in CSF. Lactulose showed effects similar to those of lactitol. These findings suggest that lactitol may be a promising agent for the clinical treatment of hyperammonemia and hepatic encephalopathy, since it decreased the concentration of ammonia in the blood and CSF and the elevated concentrations of AAA in CSF associated with the development of hepatic encephalopathy.

High-energy underwater shock wave treatment for internal iliac muscle metastasis of prostatic cancer: a first clinical trial

The first clinical trial of high-energy shock wave (SW) combined with chemotherapy to treat metastasis of prostate cancer in the internal iliac muscle was conducted. The patient, a 57-year-old man, diagnosed as having mucin-producing, poorly differentiated adenocarcinoma of the prostate invading the bladder wall, had been treated by total cystoprostatectomy. Five months later, metastatic tumors were found in the left axillar subcutaneous tissue and the right internal iliac muscles. For the axillar metastasis we performed radiation and left subclavicular arterial infusion of cisplatin 70 mg, THP-adriamycin (THP) 50 mg and methotrexate 50 mg. For the right internal muscular metastasis, 10,000 to 20,000 shots of SW and simultaneous intravenous injection of carboplatin 100 mg and THP 10 mg were carried out. Neither of the tumors decreased in size, but on magnetic resonance images, the SW-treated tumor exhibited a central low-intensity area. The SW-treated tumor was resected and central necrosis and a collection of mucin in the central area were observed. Hormone-resistant prostate cancer is well-known to be a multidrug-resistant tumor. It is noteworthy that SW and chemotherapy induced necrosis in such a refractory cancer without any significant side effects.

[Ureteritis cystica--report of a case diagnosed by biopsy under ureteroscopy]

A 62-year-old male with left ureteritis cystica was reported. Extracorporeal shock wave lithotripsy (ESWL) was performed for his left renal stone 14 and 17 months earlier. However, small fragments remained in the lower calyx and pyuria, microhematuria and bacteriuria continued. Drip infusion pyelography (DIP) showed a small filling defect of the left dilated ureter. Retrograde pyelography revealed multiple, small filling defects of the left middle through the lower ureter. Multiple small submucosal cysts were observed mostly in the pelvic ureter by ureteroscopic examination. Ureteroscopic cold punch biopsy proved ureteritis cystica. The ureteral dilatation improved and filling defects disappeared after the treatment with antibiotics.

Different organization of intermediate filaments in columnar cells of rat large intestinal mucosa as revealed by confocal laser scanning microscopy and quick-freezing and deep-etching method

The relationship between cell differentiation and ultrastructural changes of intermediate filaments (IF) was studied in columnar cells of large intestinal mucosa of rats by confocal laser scanning microscopy and quick-freezing and deep-etching method. A feature of the IF in immature columnar cells was minibundle formation with prominent branching, which organized the meshwork structures. The minibundles, which appeared to be formed by the attachment of two or more IF in side-to-side fashion, were loosely distributed throughout the cytoplasm. In contrast, in mature columnar cells, the IF were densely distributed under the terminal web in the cytoplasm and beneath the upper part of the lateral membrane regions, whereas the other areas of the cytoplasm contained only a small number of IF. Minibundle formation was not observed, and the branching was rarely identified. The changes in the distribution and density of IF, which are expressed in specific areas of mature columnar cells, apparently represent a characteristic of intracellular differentiation. It is suggested that the dissociation of minibundled IF, which was often observed in the immature columnar cells, is an important step in the acquisition of functional polarity in cells of this type.

Transient Activation and Tyrosine Phosphorylation of a Protein Kinase in Tobacco Cells Treated with a Fungal Elicitor

Suspension-cultured tobacco cells respond to fungal elicitor by activating the transcription of so-called defense genes. This response has been shown to be blocked by staurosporine, an inhibitor of protein kinases, and by Gd3+, which blocks Ca2+ channels. We report here that treating tobacco cells with the elicitor triggers the rapid and transient activation of a 47-kD protein kinase that phosphorylates serine and/or threonine residues of the myelin basic protein (MBP). Staurosporine and Gd3+ inhibited the elicitor-induced activation of the 47-kD MBP kinase, and staurosporine inhibited the activity of the MBP kinase itself. In the presence of either cycloheximide or calyculin A, the elicitor induced sustained activation of the MBP kinase. Immunoblot and immunoprecipitation analysis using a phosphotyrosine-specific antibody showed that tyrosine phosphorylation of the 47-kD MBP kinase was induced in tobacco cells that had been treated with the elicitor. The results suggest that the 47-kD MBP kinase is a component of the pathway for transduction of the elicitor signal in tobacco cells and that the activity of the MBP kinase is regulated by the post-translational phosphorylation of tyrosine residues.

C1q-binding immunoglobulin G in MRL/l mice consists of immune complexes containing antibodies to DNA

Previous studies have shown that the majority of C1q-binding IgG in patients with systemic lupus erythematosus (SLE) is composed of autoantibodies to the collagen-like region of C1q. Mice of the MRL/l strain are considered as a murine model of human SLE and possess autoantibodies to nuclear antigens as well as IgM and IgG rheumatoid factors (RF). This study was undertaken to characterize the C1q-binding IgG in MRL/l mice. In contrast to human SLE, C1q-binding IgG in MRL/l mice showed immunochemical characteristics of immune complexes rather than those of autoantibodies to C1q. Namely, C1q-binding IgG in MRL/l mice was large-sized upon HPLC gel filtration and abolished by digestion with pepsin or by high salt concentration, and bound to the globular region of C1q. The C1q-binding activity in MRL/l mice was absorbed by double-stranded DNA- or single-stranded DNA-cellulose. The medium-sized immune complexes containing RF have been well documented in MRL/l mice. In this study, however, mouse IgG-Sepharose failed to absorb fully C1q-binding IgG. We conclude that the majority of C1q-binding IgG in MRL/l mice consists of large-sized immune complexes containing antibodies to DNA.

Symphalangism (two phalanges) in the digits of the Japanese foot

We report here an investigation into the number of phalanges of the 2nd to 5th toes in a Japanese population. The number of phalanges in each of these toes is normally three, distal, middle and proximal. However, occasionally only two phalanges are observed. In this condition, known as symphalangism, the middle and distal phalanges are fused (synarthrosis of the distal interphalangeal joint). The incidence of symphalangism in the 488 feet was found to be 72.5% in the 5th toe, 11.9% in the 4th toe, 0.8% in the 3rd toe, and 0.0% in the 2nd toe. No left-to-right or sex differences were observed. The reported overall incidence of symphalangism in the 5th toe of the foot in the Japanese population (74.7%) is significantly higher than that in the European population (40.2%). In the present sample, the incidence of symphalangism of the 4th toe (11.9%) was significantly higher than that in Japanese population samples previously studied (4.2%).

Effects of glucose and SNK-860, an aldose reductase inhibitor, on the polyol pathway and chemiluminescence response of human neutrophils in vitro

An in vitro incubation study was conducted to investigate whether increased activity of the polyol pathway in human neutrophils under diabetic conditions resulted in a decrease of superoxide anion produced by NADPH oxidase on the membrane of neutrophils. Lucigenin-enhanced chemiluminescence (CL) to phorbol myristate acetate as respiratory burst and sorbitol levels in neutrophils after incubation with glucose and an aldose reductase (AR) inhibitor, SNK-860 (SNK) were measured. Sorbitol levels increased from 0.210 +/- 0.029 nmol 10(7) cells-1 in 5 mmol l-1 glucose to 0.446 +/- 0.036 nmol 10(7) cells-1 in 40 mmol l-1 glucose, while CL decreased from 0.542 +/- 0.034 cpm cell-1 in 5 mmol l-1 glucose to 0.430 +/- 0.018 cpm cell-1 in 40 mmol l-1 glucose. The addition of 10 mumol l-1 SNK normalized the increased sorbitol levels in neutrophils exposed to 40 mmol l-1 glucose and improved, but did not normalize, the decrease in CL induced by 40 mmol l-1 glucose (p < 0.001). Galactose (40 mmol l-1) also reduced CL, which was improved by the addition of SNK (p < 0.01). These results suggest that impaired respiratory burst induced by high-glucose concentrations is caused by competition for NADPH resulting from increased polyol pathway activity and/or glycation and that an AR inhibitor may be capable in part of preventing increased susceptibility to infection in diabetic patients.

Traumatic rupture of the extensor tendons at the musculotendinous junction

Ten cases of closed extensor tendon rupture at the musculotendinous junction are reported. In five patients the rupture occurred at work, and in five during athletic activities. In each instance, indirect tendon injury resulted from a strong stretching force applied to a contracting muscle. In one case, rupture of the extensor pollicis longus tendon occurred proximal to the extensor retinaculum. In eight cases of complete tendon rupture direct repair was impossible. Of these eight patients, five were treated by side-to-side juncture and three by tendon transfer. Two patients with incomplete rupture were treated by splinting. All patients improved after treatment.

Dynamic analysis of intraarticular pressure in the glenohumeral joint

Dynamic analysis of intraarticular pressure was performed in 180 glenohumeral joints. The intraarticular pressure demonstrated characteristic changes during shoulder movement. In the healthy group minimum pressure was measured at 40 degrees of elevation in the scapular plane. In patients with contractures the pressure increased in the early phase of elevation and persisted. Pressure changes of the group with incomplete tears of the rotator cuff resembled those of the healthy group, whereas those in the massive tear group showed only slight pressure changes. When patients with rotator cuff tears had no limitation of arm elevation, pressure changes close to the normal pattern were found. However, when active elevation was markedly limited, no significant pressure changes were noted in some cases. In unstable shoulders the rate of pressure increase was slower, and the range of pressure changes was more limited than that in the healthy group. It is speculated that changes in intraarticular pressure reflect the intraarticular volume. Measurement of the intraarticular pressure may be clinically useful in functional assessment.

Backscattered electron imaging of crystal matrix protein on the surface of calcium oxalate crystals using colloidal gold

In order to clarify the presence and localization of crystal matrix protein (CMP) upon calcium oxalate crystals, scanning electron microscopy (SEM) and backscattered electron imaging (BEI) techniques were used. This protein exhibits a remarkable affinity with calcium oxalate crystals and may be important in stone pathogenesis. In this paper, rabbit anti-human CMP polyclonal antibody was used as first antibody, and for the second antibody, goat anti-rabbit IgG conjugated with 20 nm immunogold was used. Freshly prepared crystals from male urine were fixed in SEM fixative, then blocked and washed with phosphate-buffered saline and bovine serum albumin (PBS/BSA). First and second antibodies were reacted in PBS/BSA. Crystals were then dehydrated and finally coated for SEM study. The SEM technique showed bipyramidal shaped dihydrate calcium oxalate crystals in every sample and even at high magnification, colloidal gold could barely be seen. BEI clearly demonstrated the presence and localization of the gold on the surface of the crystals as well as on the macromolecules eluted from the crystals by dissolving them in ethylenediamminetetraacetic acid solution.

Classification of hepatitis C virus into major types and subtypes based on molecular evolutionary analysis

Molecular evolutionary analysis was applied to determine the number of hepatitis C virus (HCV) types and subtypes based on all the HCV nucleotide sequences available from the DNA data banks (DDBJ, GenBank (NCBI), EMBL) and the literature. There was an excellent concordance among the types and subtypes assigned based on different HCV genomic regions. Only one HCV isolate was assigned to different HCV types based on the 5' non-coding (NC) and envelope 1 (E1) regions. The 5' NC region was well conserved and could be used to assign only types and not subtypes. From the sequence data available there were 13 subtypes based on the core region and 14 subtypes based on the E1 and non-structural protein 5 (NS5) regions.

Activation of the basolateral Cl- conductance by cAMP in rabbit renal proximal tubule S3 segments

The regulatory mechanism of basolateral Cl- conductance in rabbit renal proximal tubule S3 segments was investigated with conventional and Cl- sensitive microelectrodes. After the basolateral Cl-/HCO3- exchanger was blocked by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) we increased the bath K+ concentration from 5 mmol/l to 20 mmol/l, which depolarized the cells and thereby increased intracellular Cl- activity ([Cl-]i). This [Cl-]i response was enhanced by +63% in the presence of forskolin (20 mumol/l), by +40% in the presence of dibutyryl adenosine 3',5'-cyclic monophosphate (db-cAMP) (1 mmol/l) and by +44% in the presence of parathyroid hormone (PTH, 10 nmol/l), whereas it was inhibited by a Cl- channel blocker, indanyl-oxyacetic acid (IAA-94, 0.3 mmol/l). In addition, forskolin, PTH and chlorophenylthio-cAMP enhanced the electrogenic response to removal of bath Cl- after the blockade of K+ conductance, and this activation was also sensitive to IAA-94. On the other hand, 2 mumol/l ionomycin and 0.5 mumol/l phorbol myristate failed to activate the [Cl-]i response to elevation of bath K+ concentration and the electrogenic response to Cl- removal, and ionomycin had no effect even in the absence of DIDS. These results indicate that this basolateral Cl- conductance can be activated by cAMP, while neither the increase in cytosolic Ca2+ nor the activation of protein kinase C has direct effects on this conductance.

Suppression of reperfusion arrhythmia by ischemic preconditioning in the rat: is it mediated by the adenosine receptor, prostaglandin, or bradykinin receptor?

The mechanism for the suppression of reperfusion arrhythmia by preconditioning (PC) remains unknown. This study aimed to examine the roles of the adenosine receptor, prostaglandin (PG), and bradykinin (BK) receptor in PC. Under pentobarbital anesthesia, the coronary artery of the rat was occluded for 5 min and then reperfused. In untreated controls, this protocol induced ventricular tachycardia (VT) in 100% of the rats and ventricular fibrillation (VF) in 60%. PC with 2 min ischemia/5 min reperfusion prior to the 5 min coronary occlusion significantly reduced the incidence of reperfusion VT and VF to 30% and 0%, respectively. This antiarrhythmic effect of the PC was not blocked when rats were pretreated with 8-phenyltheophylline (8-PT, 10 mg/kg), aspirin-DL-lysin (18 mg/kg), or a specific BK receptor antagonist, Hoe140 (20 nmol/kg). None of these agents alone significantly modified the incidence of reperfusion VT or VF. These results suggest that neither the adenosine receptor, endogenous PG, nor BK receptor play a major role in the mechanism of suppression of perfusion arrhythmias by PC in the rat heart.

Inheritance of seed α-amylase inhibitor in the common bean and genetic relationship to arcelin

The inheritance of seed α-amylase inhibitor in the common bean and the genetic relationships among the variants and six arcelin variants in the common bean were investigated by crossing between accessions containing different αAI and arcelin variants. All seed proteins in parental, F1 and F2 seeds from the crosses were examined by Western-blot analysis. All F1 seeds gave combined αAI banding patterns from parents on the blotting membranes. The segregation of F2 seeds for αAI variants indicated that the polypeptides of αAI variants were inherited as single co-dominant units. Moreover, αAI and arcelin behaved as a single block in crosses, indicating a close linkage relationship between the genes controlling these proteins.