Src homology 2 domains of protein tyrosine phosphatase are phosphorylated by insulin receptor kinase and bind to the COOH-terminus of insulin receptors in vitro

To clarify the role of protein tyrosine phosphatases(PTPase) containing Src homology 2 (SH2) regions on insulin signaling, we investigated the interactions between SH2 regions of PTPase and insulin receptors. We made a pair of SH2 domains of PTP1C and SH-PTP2 fusion proteins coupled to glutathione-S-transferase (GST) using pGEX-3X expression vector. After incubating with insulin, insulin receptors were incubated with SH2 proteins in the presence of 100 mu ATP at 4 degrees C for 3 hr, and then immunoprecipitated and analyzed by SDS-PAGE. We found that SH2 domains of SH-PTP2 were phosphorylated, but not those of PTP1C by insulin receptor kinase and the SH2 domains of SH-PTP2, but not those of PTP1C, directly bound to the phosphorylated COOH-terminus of insulin receptors in vitro.

Molecular cloning and characterization of a human carboxylesterase gene

A cDNA encoding human liver carboxylesterase and its gene were isolated. Nucleotide sequence analyses of the cDNA revealed that the predicted enzyme protein consists of 567 amino acids, including 18 amino acids of a putative signal peptide. Comparison of the deduced amino acid sequences of this enzyme with those of seven other carboxylesterases in various mammalian species, together with experimental data from several other laboratories, showed that these enzymes can be classified into three groups depending on the sequences at their carboxyl terminals and the presence or absence of one exon. A human carboxylesterase gene was found to span approximately 30 kb and to have 14 small exons. Alignments of this gene with those of human cholinesterase and rat cholesterol esterase indicated insertional sites at some introns and homologous amino acid sequences around them, although these genes have different numbers of exons. Thus the results supported the conclusion that these esterases evolved from a common ancestral gene.

Enhanced c-fos expression after intracellular iron deprivation

Intracellular iron deprivation by deferoxamine treatment, which leads to cells arrest in the S phase, enhanced c-fos expression in the neuroblastoma cell line, IMR32. The c-fos expression of iron deprived cells retained its response to stimulation by TPA, and cytosolic PKC activity did not decline after iron deprivation. The data suggest that PKC was not down-regulated. Creatine kinase activity also remained constant in the cytosol of iron deprived cells, indicating intact cellular function. Iron deprivation may activate the growth-related oncogene, c-fos, through some means other than the PKC pathway.

[A case report underwent simultaneous CEA and CABG followed by FPB]

A case of 67-year-old man with stenoses of both carotid arteries, double vessel diseases of coronary arteries, and left superficial femoral artery obstruction, for which surgical treatments were performed, is herein reported. He was in HYHA class IV because of unstable angina pectoris and pain in the left leg and in the state of chronic renal and hepatic disorders which made his condition worse. Coronary angiography showed stenoses in the origin of the right coronary artery and in the proximal left anterior descending artery at the degrees of about 95% and 90%, respectively. Carotid arteriography revealed both internalcarotid artery stenoses over 90%. The left carotid endarteractomy was not indicated because of presence of obstructive lesions of intracranial arteries in the left side. He underwent simultaneous surgery for the coronary and carotid occlusive diseases. He gained consciousness at the post operative 1st day and underwent left femoroperoneal saphenous vein bypass at the post operative 2nd day. He is leading a normal life without angina pectoris, left intermittent claudication and neurological deficit and has been followed up for 9 months postoperatively.

Alanyl glutamine-enriched total parenteral nutrition restores intestinal adaptation after either proximal or distal massive resection in rats

This study was designed to determine whether alanyl glutamine-containing total parental nutrition (TPN) can restore the impaired adaptive process of the remaining intestine, observed with administration of conventional TPN, after massive small-bowel resection. Seventy-four male Sprague-Dawley rats weighing 250 g were randomly divided into seven groups. Group I rats (n = 10) were killed after overnight fasting. Group II animals (n = 32) underwent massive small bowel resection (85%) with preservation of the first 15 cm of jejunum. Group III animals (n = 32) were also submitted to massive small-bowel resection with preservation of 15 cm of terminal ileum. Three different TPN solutions were prepared. Solution A was a conventional formulation that did not contain glutamine. Solution B contained 1.88 times the amino acid concentration of solution A. Solution C was prepared by adding alanyl glutamine (2 g/100 mL) to solution A. Solutions B and C were isonitrogenous and isocaloric. Each solution was infused to groups II and III, which were subdivided into groups IIA (n = 10), IIB (n = 11), IIC (n = 11), IIIA (n = 10), IIIB (n = 11), and IIIC (n = 11). After 1 week of TPN (270 kcal/kg per day), the experimental animals were killed and the intestine was taken for examination. Final body weight did not differ significantly among the groups, and there was no difference in nitrogen balance among the animals that received solution B or C.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of acetylcholine release in the hippocampus by 6R-L-erythro-5,6,7,8-tetrahydrobiopterin is mediated by 5-hydroxytryptamine

Recently, we reported that 6R-L-erythro-tetrahydrobiopterin (6R-BH4), a natural cofactor for L-aromatic amino acid hydroxylases, enhances in vivo release of acetylcholine (ACh) in the rat hippocampus: the enhancement was abolished after depletion of brain catecholamines and 5-hydroxytryptamine (5-HT) by pretreatment with reserpine. In the present study, we have used in vivo brain microdialysis to clarify the neuronal mechanism involved in the enhancement of ACh release by 6R-BH4. After depletion of catecholamines by pretreatment of rats with alpha-methyl-p-tyrosine, 6R-BH4 added to the perfusion fluid still induced an increase in extracellular ACh levels monitored by microdialysis as an index of ACh release. In contrast, after depletion of 5-HT by pretreatment with p-chlorophenylalanine, most of the 6R-BH4-induced enhancement was eliminated. Exogenous 5-HT and dopamine (DA) but not noradrenaline added to the perfusion fluid stimulated ACh release with 5-HT being far more potent. Intraperitoneal administration of 5-hydroxytryptophan and L-DOPA also enhanced ACh release, presumably by their conversion to 5-HT and catecholamines, respectively. Administration of 6R-BH4 increased hippocampal 5-HT release, as indicated by increased extracellular levels of the major 5-HT metabolite, 5-hydroxyindoleacetic acid. These results suggest that 6R-BH4 stimulates ACh release in the hippocampus, mainly by augmenting release of 5-HT, a potent stimulator of ACh release, and partly by augmenting release of DA.

Detection of collagenase mRNA in odontoclasts of bovine root-resorbing tissue by in situ hybridization

The odontoclast, which is morphologically similar to osteoclast, is thought to play a major role in root resorption of deciduous teeth. High collagenolytic activity has been detected in the root resorbing tissue. In order to identify collagenase-producing cells and the role of collagenase in root resorption of deciduous tooth, in situ hybridization of collagenase mRNA in bovine root-resorbing tissue sections was performed using a digoxigenin-labeled, nonradioactive RNA probe. Collagenase mRNA expression was clearly observed in odontoclasts in addition to the macrophages, fibroblasts, odontoblasts, and cementoblasts. Multinuclear odontoclasts showed intense tartrate-resistant acid phosphatase (TRAP) activity. We also examined interleukin-1 (IL-1) mRNA expression in the root-resorbing tissue by in situ hybridization. IL-1 transcripts were found to be expressed in odontoclasts, fibroblasts, and macrophages suggesting that IL-1 might be an important factor for promoting root resorption. These results suggest that the collagenase produced by odontoclasts may play a key role in dentin collagen degradation in root resorption.

Processing of epidermal glucosylceramides is required for optimal mammalian cutaneous permeability barrier function

The interstices of the mammalian stratum corneum contain lipids in a system of continuous membrane bilayers critical for the epidermal permeability barrier. During the transition from inner to outer stratum corneum, the content of polar lipids including glucosylceramides, decreases while ceramide content increases. We investigated whether inhibition of glucosylceramide hydrolysis would alter epidermal permeability barrier function. Daily topical applications of bromoconduritol B epoxide (BrCBE) to intact murine skin selectively inhibited beta-glucocerebrosidase, increased glucosylceramide content of stratum corneum with ceramide content remaining largely unchanged, and caused a progressive, reversible decrease in barrier function. Histochemistry of inhibitor-treated epidermis revealed persistence of periodic acid-Schiff-positive staining in stratum corneum cell membranes, consistent with retention of hexose moieties. Electron microscopy of inhibitor-treated samples revealed no evidence of toxicity or changes in the epidermal lipid delivery system. However, immature membrane structures persisted in the intercellular spaces throughout the stratum corneum, with reappearance of mature membrane structures progressing outward from the lower stratum corneum upon termination of BrCBE. Finally, the induced barrier abnormality was not reversed by coapplications of ceramide. These data demonstrate that glucosylceramide hydrolysis is important in the formation of the epidermal permeability barrier, and suggest that accumulation of glucosylceramides in stratum corneum intercellular membrane domains leads to abnormal barrier function.

[A case report of total intravenous anesthesia for renal transplantation]

A 20-year-old female patient with chronic renal failure received renal transplantation under total intravenous anesthesia with droperidol, fentanyl and ketamine. Anesthesia was induced with droperidol 12.5 mg, fentanyl 100 micrograms, ketamine 100 mg and vecuronium bromide 5 mg, and maintained with fentanyl and ketamine. Ketamine was given continuously at a rate of 2.0 mg.kg-1.h-1. After the renal artery and vein of the donor kidney were anastomosed with the patient's internal iliac artery and vein, the urine output of 7.7 ml.min-1 was obtained. The patient recovered from anesthesia smoothly and her postoperative course was uneventful. Although plasma epinephrine, cortisol and ADH levels showed significant changes during anesthesia mainly due to surgical stress, they returned to normal values after the end of operation. We conclude that this method of anesthesia would be a choice for renal transplantation.

Evidence that cyclosporine causes both intracellular migration and inappropriate urinary excretion of magnesium in rats

We determined the effects of cyclosporine on calcium, magnesium, and potassium metabolism in rats. Thirty Sprague-Dawley rats were randomized into three groups of ten animals each--control rats given olive oil, rats given cyclosporine at a dosage of 5 mg/kg daily, and rats given 15 mg/kg daily for four weeks. Urinary excretion of calcium, magnesium, and potassium was determined before and after 2 and 4 weeks of cyclosporine therapy. All rats were sacrificed after 4 weeks of therapy, and calcium, magnesium, and potassium concentrations in serum and tissues were determined. Serum magnesium levels were significantly lower in the cyclosporine-treated groups than in the control group, but there was no significant difference between the control and either of the cyclosporine-treated groups with regard to total urinary excretion of magnesium after four weeks of treatment. Magnesium content in the kidney, muscle, and liver was significantly higher in the 15 mg/kg group than in the control group. Calcium content in the kidney and liver was significantly higher as well. Potassium content in any type of tissue was similar in the three groups. We conclude that the intracellular migration of magnesium plays an important role--as does impaired renal conservation of magnesium--in the pathogenesis of cyclosporine-induced hypomagnesemia and that there is a discrepancy between magnesium and potassium metabolism in cyclosporine-treated rats.

Intracranial calcifications associated with nephrogenic diabetes insipidus

A 6-year-old boy with nephrogenic diabetes insipidus (NDI) and intracranial calcification is reported. The calcifications were symmetrical and located in the basal ganglia and in the subcortical regions of the frontal, temporal, parietal and occipital lobes. Episodes of hyperosmolality during infancy are considered to be one of the causes of intracranial calcification in NDI. However, other unknown factors may be involved, because up to now there have been no reports of intracranial calcification in patients with central diabetes insipidus.

Effects of verapamil on the cardiac alpha 1-adrenoceptor signalling system in diabetic rats

We evaluated the effects of chronic verapamil treatment on the cardiac alpha 1-adrenoceptor signalling system in streptozocin-induced diabetic rats. The decrease in maximum cell surface [3H]bunazosin binding (Bmax) in isolated cardiac myocytes from the diabetic group (-46%, P < 0.01) was completely reversed by a 4-week course of verapamil, while Bmax in the verapamil-treated control group was unchanged. Similarly, the reduction in ventricular inositol 1,4,5-trisphosphate (IP3) production after stimulation with 10 microM noradrenaline (NA) seen in diabetes (-30%, P < 0.01) was completely normalized by verapamil, while the response in the verapamil-treated control group was unaffected. These results indicate that verapamil can induce complete recovery of the impaired cardiac alpha 1-adrenoceptor signalling system in the diabetic heart without affecting glucose metabolism.

An isozyme of microsomal carboxyesterases, carboxyesterase Sec, is secreted from rat liver into the blood

It is generally believed that liver carboxyesterases are localized exclusively in the endoplasmic reticulum (ER), mostly in the lumen, loosely bound to the inner side of the membrane. A cDNA clone, clone (8-1/2-1) supposed to code for one of the isozymes, carboxyesterase E1, was isolated by Takagi et al. [J. Biochem. 104, 801-806 (1988)]. However, the protein coded by clone (8-1/2-1) had no consensus ER retention signal at its carboxy terminus, and the mechanism of its retention by ER lumen was unclear. When clone (8-1/2-1) was expressed in COS cells in this study, the plasmid-coded protein was secreted into the medium. When the carboxy terminal portion of the clone (8-1/2-1)-coded protein was replaced with the corresponding region of another carboxyesterase, pI 6.1 esterase, which had the HVEL sequence at the carboxy terminus, the chimeric protein was retained in the COS cells. We searched for a secretory form carboxyesterase in rat blood immunochemically using polyclonal antibodies to carboxyesterase E1, and detected a cross-reacting protein with a molecular weight of 68 kDa. The molecular weight was decreased by endoglycosidase F treatment but not by endoglycosidase H treatment, indicating that the protein carries complex type sugar chains. In addition, the cross-reacting protein was labeled with [3H] diisopropylfluorophosphate (DFP), suggesting that the protein has an esterase-type active center serine.(ABSTRACT TRUNCATED AT 250 WORDS)

Squamous cell carcinoma-associated antigen in uroepithelial carcinoma

We investigated the clinical significance of squamous cell carcinoma (SCC) antigen determined by radioimmunoassay on patients with uroepithelial carcinoma. Serum SCC antigen levels and the positive rates were significantly higher in uroepithelial carcinoma having an SCC component than in normal controls, benign urologic diseases, other urogenital carcinomas, or in pure transitional cell carcinoma (TCC) of uroepithelial carcinomas. A substantial number of patients with pure TCC showed a positive serum level of SCC antigen. Immunohistochemical staining of SCC antigen on the uroepithelial carcinomas confirmed that some, not all, pure TCC, mostly grade 3, expressed SCC antigen in their cells. These results suggested a biologic characteristic of grade 3 TCC which is closely related to that of SCC. The serum levels of SCC antigen correlated well with the disease extensions in uroepithelial carcinoma containing SCC component. Changes in serum levels of SCC antigen following treatment reflected the clinical courses of patients, particularly in those with elevated pretreatment levels. The results of our study indicated that the determination of SCC antigen would be clinically useful for monitoring clinical courses of patients with uroepithelial carcinomas containing SCC component and of those with pure TCC whose pretreatment level was elevated.

[A case of CA19-9 producing transitional cell carcinoma of the ureter effectively responsive to combination chemotherapy]

We report a case of CA19-9 producing transitional cell carcinoma of the right ureter effectively responsive to combination chemotherapy (methotrexate, vinblastine, doxorubicin and cisplatin (M-VAC) regimen) in a 53-year-old woman. The maximum level of serum CA19-9 showed 3,000 U/ml and clinical staging of the tumor was T4 N3 M0. Marked regression of the tumor was identified by computed tomographic scan and the level of serum CA19-9 returned to the normal range after 3 courses of M-VAC therapy. Right total nephro-ureterectomy and partial cystectomy was done and the surgical specimen revealed no viable tumors. She is alive without evidence of local recurrence or metastasis at 6 months after resection. The serum CA19-9 level was useful for monitoring the clinical course.

Prevention of catheter-related sepsis during parenteral nutrition: effect of a new connection device

A prospective study was carried out to determine the clinical effect of a newly devised catheter connection method (I system) and piggyback access system. Previous studies have demonstrated that the I system avoided bacterial contamination in vitro during tubing change that Luer-Lock connectors did not. The purpose of this study was to investigate the ability of this device coupled with a new closed-system piggyback technique for multipurpose access to reduce catheter-related sepsis in clinical practice. Two hundred and thirty patients receiving total parenteral nutrition were divided into two groups. Group I (n = 106) used the I system connector and group L (n = 124) used a Luer-Lock connector. Catheters in both groups were used for multipurpose access for infusion and blood sampling. In group L, a three-way stopcock and/or pig-gyback system was used for multiple access. In group I, a newly designed closed-system piggyback was used. The incidence of catheter-related sepsis was significantly lower in group I (1.89%/catheter) than in group L (12.10%/catheter) (p < .01, chi 2 analysis), and the average duration of use of each catheter was significantly longer in group I than in Group L (p < .01 by generalized Wilcoxon test). The results of this clinical study suggest that the newly designed connection method and piggyback access system are able to reduce catheter-related sepsis.

Increase in cardiac muscle fructose content in streptozotocin-induced diabetic rats

To evaluate the activation of the sorbitol pathway in cardiac muscle in diabetic rats, we measured sorbitol, fructose, and myo-inositol content in cardiac tissue obtained from control and streptozotocin-diabetic rats, with or without an 8-week insulin treatment, using gas chromatography-mass spectrometry (GC-MS). Cardiac fructose and sorbitol content in 10-week diabetic rats increased by 60-fold and 3.9-fold of those of control rats, respectively (P less than .001). In contrast, cardiac myo-inositol content in 10-week diabetic rats decreased to 56% (P less than .025) of the control value. The abnormalities in cardiac fructose, sorbitol, and myo-inositol content were completely normalized by the 8-week insulin treatment, which was initiated 2 weeks after the induction of diabetes. There was no difference in cardiac aldose reductase activity between control and diabetic rats. However, cardiac sorbitol dehydrogenase activity in diabetic rats was 151% (P less than .005) higher than that of control rats, although hepatic sorbitol dehydrogenase activity was not different between the two groups. These results indicate that the sorbitol pathway is significantly activated in cardiac tissue obtained from streptozotocin-induced diabetic rats, which results in the marked cardiac accumulation of fructose.

Zinc-deficient diet impairs adaptive changes in the remaining intestine after massive small bowel resection in the rat

An investigation was conducted on the influence of the presence of zinc in an elemental diet on the mucosa of residual intestine after massive small bowel resection. A total of 34 male Sprague-Dawley rats were divided into five groups: control animals (n = 10) were killed after overnight fasting; a second group (n = 14) underwent massive small bowel resection preserving 10 cm of terminal ileum, and the third group (n = 10) underwent sham operation. Animals in the second and third groups were fed either a commercially available elemental diet or a zinc-deficient diet for 2 weeks; they were then killed. In animals receiving the zinc-deficient diet, a significant decrease (P < 0.05) was noted in plasma zinc and total protein, and in mucosal wet weight (duodenum), thickness (duodenum and ileum), and protein (duodenum) and DNA (duodenum) content. Mucosal sucrase and maltase specific activities in the duodenum and ileum fell but diamine oxidase levels did not. These results suggest that zinc plays an important role in intestinal adaptation in the rat, and indicate that this trace element is essential for intestinal mucosal preservation in this animal.

Identification of an amino acid residue involved in the substrate-binding site of rat liver uricase by site-directed mutagenesis

Computer analysis has shown that a conserved amino acid sequence (Leu 160 to Lys 164) of rat liver uricase is also present in other enzymes with purine substrates. The significances of the amino acids in this sequence were studied by site-directed mutagenesis. Replacement of Lys 164 by Glu or Ile resulted in loss of uricase activity and decrease in binding of the competitive inhibitor xanthine. The far ultraviolet circular dichroic spectra of the mutant uricases were identical to that of the wild type protein, indicating that the replacement of Lys 164 by other amino acids did not result in serious modification of the conformation of uricase. These findings suggest that this amino acid is involved in the substrate-binding site of the enzyme.

beta-Glucocerebrosidase activity in murine epidermis: characterization and localization in relation to differentiation

The intercellular lipids of the stratum corneum, which are highly enriched in ceramides, are critical for the mammalian epidermal permeability barrier. During the terminal stages of epidermal differentiation, the glucosylceramide content is dramatically reduced, while the content of free ceramides increases. To investigate whether beta-glucocerebrosidase (beta-GlcCer'ase) could be responsible for this change in lipid content, we characterized its activity in murine epidermis, compared enzyme activity to other murine tissues, and localized beta-GlcCer'ase activity within the epidermis. Epidermal extracts demonstrated linear 4-methylumbelliferyl-beta-D-glucose hydrolysis (to 3 h) with protein concentrations between 1 and 250 micrograms/ml. Whole epidermis contained comparable beta-glucosidase activity (9.1 +/- 0.4 nmol/min per mg DNA) to murine brain and liver, and 5-fold higher activity than spleen. Epidermal beta-glucosidase activity was stimulated greater than 15-fold by sodium taurocholate at pH 5.6, and inhibited at acidic pH (3.5-4.0). Bromoconduritol B epoxide (greater than or equal to 1.0 microM), inhibited epidermal enzyme activity by greater than 75%, while activity in brain, liver, and spleen was only inhibited by 6, 17, and 14%, respectively. Moreover, beta-GlcCer'ase mRNA expression in murine epidermis exceeded levels in liver, brain, and spleen. Finally, beta-GlcCer'ase activity was highest in the outer, more differentiated epidermal cell layers including the stratum corneum. In summary, mammalian epidermis contains an usually high percentage (approximately 75%) of beta-glucocerebrosidase activity, and the concentration of activity in the more differentiated cell layers may account for the replacement of glucosylceramide by ceramides in the outer epidermis.

[Problems and prevention in using arterial grafts for coronary artery bypass grafting]

The arterial graft has proved to be superior to the saphenous vein graft for coronary bypass grafting (CABG), because of its excellent long-term patency. However, there mains controversial on the choice of the arterial grafts. Six hundreds and twenty seven patients who had CABG using both arterial grafts and saphenous vein grafts, operated upon over 11-years period between 1980 and 1991, have been analysed. Some disadvantages and complications associated with the use of arterial grafts were demonstrated in our series. We discussed, the flow capacity, myocardial protection and postoperative complications in using arterial grafts for CABG.