Purification, reconstitution, and cloning of an NMDA receptor-ion channel complex from rat brain synaptic membranes: implications for neurobiological changes in alcoholism.
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Biomedical subjects
Publications and source records attributed to H Minami.
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A calcyclin-associated protein with an apparent molecular weight of 50,000 (CAP-50) was purified from rabbit lung. The procedure included ammonium sulfate precipitation, anion and cation ion-exchange, and calcyclin affinity chromatographies. Interestingly, partial amino acid sequences of lysyl-endpeptidase-digested fragments indicated that CAP-50 was a member of the Ca2+/phospholipid-binding proteins, the annexin family. The sequence of a proteolytic peptide with Staphylococcus aureus V8 protease on NH2-terminal region is not homologous with any other annexin family proteins. Phospholipid binding studies showed that CAP-50 bound to phosphatidylserine, phosphatidylethanolamine, phosphatidylinositol, and phosphatidic acid-containing vesicles, in a Ca(2+)-dependent manner. In the presence of Ca2+/calcyclin, CAP-50 formed a complex with calcyclin and bound to the PS-containing vesicles. The apparent Kd value of calcyclin for CAP-50 was calculated to be 1.61 x 10(-6) M. Zero-length cross-linking studies indicated that 1 mol of CAP-50 bound to an equimolar unit of calcyclin. CAP-50 inhibited the phospholipase A2 activity, dose-dependently (IC50 = 0.2 microM), however, calcyclin did not alter the inhibitory effect. With the 125I-calcyclin gel overlay method, calcyclin bound tightly to CAP-50 in a Ca(2+)-dependent manner after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results suggest that rabbit lung CAP-50 is a newly identified member of the annexin family. Ca2+/calcyclin apparently regulates the function of CAP-50 on cytosolic face of the plasma membrane.
Developmental changes in glucose transporter mRNA levels in the jejunum of rats of different ages were examined by using slot blot RNA analysis. The level of SGLT1 mRNA did not change significantly through life. The GLUT5 mRNA level was highest in 10-day-old rats and then decreased reaching the adult level by day 20 after birth. The GLUT2 mRNA level was low in rats of 5 and 10 days old, but then increased progressively reaching the adult value by day 25 after birth. These results indicate that the expressions of intestinal facilitative glucose transporter genes change markedly in the third week after birth.
A single intragastric administration of glycine, L- and D-alanine, and L-and D-serine into rats resulted in a more than 20-fold stimulation of intestinal mucosal ornithine decarboxylase (ODC) within 4 h. The stimulation of ODC activity was accompanied by an increase in the amount of immunoreactive ODC protein. The induction of ODC by D-amino acids was in all likelihood attributable to an enhanced accumulation of ODC-specific mRNA species as revealed by Northern blot and dot-blot hybridization analyses. However, the induction by glycine and L-amino acids was not explainable by changes of mRNA since the changes in mRNA contents were only marginal. Since the turnover rates of L-serine-induced and D-serine-induced intestinal ODC protein were the same as the non-induced control, we concluded that the induction by glycine and L-amino acids was brought about by an increased efficiency of translation of the ODC message.
Using in vivo and in vitro techniques, the mechanism by which intestinal mucosa obtains glutamine from luminal oligopeptides was investigated in humans. The rate of hydrolysis by mucosal brush border membrane was more than threefold greater for alanylglutamine than for glycylglutamine. Despite this difference, rates of dipeptide and amino acid disappearance during intestinal perfusion were greater from test solutions containing glycylglutamine than alanylglutamine. Furthermore, rates of intraluminal appearance of products of hydrolysis during the infusion of two dipeptides were similar and less than 5% of the disappearance rate of the parent dipeptide. In contrast to free glutamine, uptake of peptide-bound glutamine by brush border membrane vesicles was not inhibited by deletion of sodium or addition of free amino acids to the incubation medium but was inhibited by other oligopeptides and stimulated by a proton gradient. Inhibition constants for the saturable uptake of glycylglutamine and alanylglutamine by vesicles were not significantly different, suggesting similar affinities for the peptide transporter. It is concluded that in human intestine the predominant mechanism for assimilation of glutamine-dipeptides is absorption as intact dipeptide rather than hydrolysis.
Excellent results have been reported after small caliber catheters were used for iatrogenic pneumothoraces. However, the value of using such catheters for spontaneous pneumothoraces is not clear. The purpose of this study, therefore, is to examine the efficacy of small caliber catheters in managing spontaneous pneumothoraces. Seventy six episodes of spontaneous pneumothorax were treated using a small caliber catheter (No. 5.5 or 7.0 French) connected to a Heimlich valve. All catheters were inserted by physicians. The treatment was considered successful when there was no air leakage and little or no residual pneumothorax. Before the lungs were fully expanded, four patients had died and one had refused to comply with further treatment. The remaining 71 episodes of pneumothoraces were evaluated for efficacy. The treatment was successful in 60 patients (84.5%) and ineffective in the remaining 11. The conventional large caliber tube was inserted in 10 of the 11 failures, but they were successful in only six. No major complications resulting from catheter insertion occurred, and no catheters became occluded. The catheter was easy to insert, and the scar that remained after removal of the catheter was very small. Not only are small caliber catheters effective for managing spontaneous pneumothoraces, they are the initial treatment of choice.
We have investigated the relative contribution of hydrolysis, intact transport and urinary excretion to the renal clearance of Gly-Sar, Gly-Sar-Sar, and Gly-Gly-Sar in fed and starved rats. The results obtained from isolated kidney perfusion studies are summarized as follows: 1) clearance was fastest for Gly-Gly-Sar and slowest for Gly-Sar-Sar, 2) urinary excretion of Gly-Sar-Sar exceeded that of Gly-Gly-Sar or Gly-Sar, 3) there was accumulation of products of hydrolysis of Gly-Gly-Sar in the perfusate but not of Gly-Sar or Gly-Sar-Sar, 4) isolated brush-border and basolateral membranes of renal tubular cells lacked hydrolytic activity against Gly-Sar and Gly-Sar-Sar but possessed hydrolytic activity against Gly-Gly-Sar, 5) an excess amount of Gly-Sar-Sar reduced the rate of clearance of Gly-Gly-Sar by approximately 40% and significantly increased urinary excretion of this peptide, 6) the nonfiltering kidney cleared Gly-Gly-Sar at a rate which was 50% of that of the filtering kidney but did not clear Gly-Sar, and 7) starvation for 96 h was without a significant effect on the renal clearance of either Gly-Sar or Gly-Sar-Sar but significantly reduced the renal clearance of Gly-Gly-Sar and the brush-border membrane hydrolase activity against this peptide. We conclude that the molecular structure determines the affinity of oligopeptides for the membrane transport and hydrolytic systems, which, in turn, determines their efficiency for clearance by the kidney.
We report a technique for performing subcapsular orchiectomy using the ultrasonic surgical aspirator (USA). The procedure was simple and safe, and was completed within one hour in 2 patients on whom it was carried out. Operative complications such as bleeding, postoperative pain and wound swelling were minimal, and compression dressings were not necessary. Postoperatively, the serum testosterone value was lowered to the castrate level. We conclude that subcapsular orchiectomy using USA is superior to conventional bilateral scrotal orchiectomy, and will be a useful option.
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A 66-year-old male presented to our hospital in January 1990 with chief complaints of hemoptysis and cough. These symptoms had developed 10 months previously and had gradually increased. Fine crepitations were audible over the right lower lung field. There were no results suggesting an inflammatory process such as leucocytosis, elevation of ESR or positive CRP reaction. Chest X-ray film on the first visit showed fine nodular shadows in the right lower lung field, and chest CT revealed fine nodular shadows and mild dilatation of the right lower lobe bronchus. Transbronchial lung biopsy specimens showed granulomas with multinucleated giant cells, alveolitis and Masson bodies. The open lung biopsy specimens showed numerous macrophages and foreign body giant cells, and extensive organizing exudates in the bronchioles and alveolar spaces. Proliferation of smooth muscle and fibrosis around the dilated bronchioles were also seen. Thus, this patient demonstrated BOOP pattern, with granulomas and foreign body giant cells. His hemoptysis appeared to have resulted from inflammation of dilated bronchioles. His symptoms and abnormal shadows on chest X-ray improved without any therapy after admission. After treatment with corticosteroid, the diffuse fine nodular shadows disappeared. There has been no recurrence of symptoms to date, although this patient has continued living in the same environment as prior to admission. BAL findings during his prolonged follow-up revealed decrease in lymphocytes and elevation of CD4/CD8 ratio. Although the presence of granulomas suggests the possibility of an allergic reaction, no antigenic material could be identified in this case.(ABSTRACT TRUNCATED AT 250 WORDS)
A Forum discussion group hosted by Dr Eilif Liisberg was formed from a few of the participants at a WHO nursing conference in Geneva. Subjects discussed were the status of nursing and changing attitudes to patients.
The expressions of Na(+)-dependent glucose transporter (SGLT1) and five facilitative glucose transporter genes (GLUT1-5) in the small intestine of streptozotocin (STZ)-induced diabetic rats were examined by RNA blotting analysis. The transcripts of SGLT1 mRNA gave bands of 4.5 Kilobases (Kb) and 2.8Kb (very faint band). The levels of SGLT1 mRNA were significantly increased in 30- and 60-day STZ rats, but not changed in acute diabetic rats (2- to 10- day STZ rats). The GLUT2 mRNA levels changed in parallel with the D-galactose transport activity, being increased about 4-fold in 5-day STZ rats. The transcripts of GLUT5 mRNA gave three bands of 5.1Kb, 2.8Kb and 2.OKb, whose levels were significantly reduced in 30- and 60-day STZ rats. These results suggest that the facilitative glucose transporter (GLUT2), in addition to the Na(+)-dependent glucose transporter (SGLT1), may play an important role in intestinal glucose transport in diabetic rats.
We purified a new EF-hand type calcium binding protein from chicken gizzard smooth muscle, tentatively named calgizzarin (Todoroki, H., et al. J. Biol. Chem. (1991) in press. Based on the internal peptide sequence of calgizzarin, we isolated and sequenced a cDNA clone coding for calgizzarin from a rabbit lung cDNA library. This clone (pCALG) has 309 nucleotides of open reading frame including termination codon TGA, 621 nucleotides of the 5' leader and 186 nucleotides of the 3' noncoding region. The polypeptides deduced from the open reading frame were consisted of 102 amino acid residues with a molecular weight of 11,429. Computer aided homology analysis revealed that calgizzarin exhibits a 43.2% homology to S-100 alpha, 38.6% to S-100 beta and 40.0% to annexin II light chain, p10. By Northern blot analysis, with pCALG, a band of 1.1 kbp was detected in rabbit lung, suggesting pCALG contains nearly full length of mRNA.
Coulometric biosensors using glutamate receptor (GluR) ion channel protein as a signal-amplifying sensory element that exploit the glutamate-triggered Na+ ion current through bilayer lipid membranes have been fabricated. The formation of stable planar bilayer lipid membranes was achieved by applying the folding method across a small circular aperture bored through a thin polyimide film. The multichannel type sensing membranes, formed across an aperture of ca. 120 microns diameter, contained more than 10 GluR proteins and showed L-glutamate-triggered response as a composite of individual single-channel currents. The single-channel type sensing membranes, formed across an aperture of ca. 20 microns diameter, contained a sufficiently small number of GluR proteins so that the response was observed as a series of single-channel pulse currents. Dependence of the integrated channel current on the glutamate concentration was examined. A sharp concentration dependence of up to ca. 1.5 x 10(-7) M and 3 x 10(-6) M for the multichannel and single-channel type sensors, respectively, was observed. A high selectivity for L-glutamate compared with D-glutamate for inducing the channel current was observed. A detection limit as low as ca. 3 x 10(-8) M was attained for the multichannel type sensor. This remarkable sensitivity is discussed in terms of the potential use of GluR ion channel protein for a new type of sensing system.
A novel Ca(2+)-binding protein, tentatively designated calgizzarin, has been purified to apparent homogeneity from chicken gizzard smooth muscle by W-7 (N-(6-aminohexyl-5-chloro-1-naphthalenesulfonamide))-Sepharose affinity chromatography and ion-exchange chromatography. Application of W-7-Sepharose affinity chromatography to various tissues revealed that calgizzarin-like proteins were abundant in bovine aorta and rabbit lung. Using the same procedure, we could purify a calgizzarin-like protein from rabbit lung. Calgizzarin has a Mr of 13,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and approximately 30,000 as determined by gel filtration on a TSK G 3000SW high performance liquid chromatography column, suggesting that calgizzarin seems to be a rodlike protein. The isoelectric point of calgizzarin was found to be pH 5.8. Calgizzarin can exist as a dimer by forming a disulfide bridge. The 45Ca autoradiographic technique showed that the protein binds to Ca2+. On an alkaline/urea gel, calgizzarin migrated faster in the presence of EGTA than in the presence of CaCl2, thereby indicating a Ca(2+)-dependent conformational change in this protein. The partial amino acid sequence (65 amino acid residues) of calgizzarin was seen to be SLLAVFQRYAGREGDNLKLSKKEFRTFMNTELASFTKNQKDPAVVDRMMKRLDINSDGQLDFQEF, and two putative Ca(2+)-binding sites (GREGDNLKLSKKE and D INSDGQLDFQE) were detected. So far as the obtained 65-amino acid sequence is concerned, calgizzarin has approximately a 50% sequence homology with S-100 alpha, 47% with S-100 beta, and 39% with pEL-98 protein.
We present a rare case of simultaneous bilateral pneumothorax complicating bronchioloalveolar cell carcinoma. Autopsy revealed that numerous subpleural alveolar spaces were distended and most of the small airways were narrowed by cancer cells. We conclude that a check-valve mechanism may be responsible for pneumothorax in patients with bronchioloalveolar cell carcinoma.
We have evaluated the effects of LDL-aphereses performed over 15 to 62 months, involving both Double Filtration Plasmapheresis (DFPP) and LDL Adsorbent Plasmapheresis (LAPP), for 5 patients with familial hypercholesterolemia (FH) (1; homozygous, and 4; heterozygous) using computer image analysis by coronary angiography, (CAG). Results by CAG showed that in homozygous FH, 9 (75%) of 12 segments demonstrated no progression, 2 (16.7%) segments showed regression, and only 1 (8.3%) segment showed progression. In heterozygous FH, 27 (81.8%) of 33 segments showed progression, and 6 (18.2%) segments showed regression. Aorto coronary bypass was beneficial with obtained patency in 13 (93%) of the 14 grafts. We also performed an autopsy on one patient, with heterozygous FH who died suddenly probably due to fibrillation. The patient had received long-term LDL apheresis for 6 years and 7 months and had shown angiographic regression. The pathological findings showed no typical or new atheroma, significant cicatrization in the thickened intima and an eccentric thickened wall lesion. The serial angiographic findings together with the pathological findings very clearly support the use of LDL-apheresis for producing "true" regression in coronary atherosclerosis in FH.
The pharmacokinetics of a 72-hour infusion of 240 mg/m2 etoposide administered concurrently with 90 mg/m2 cisplatin was studied in 12 lung cancer patients. The area under the curve (AUC), elimination half-life, steady state concentration, systemic clearance, renal clearance of etoposide and distribution volume at steady state were 225.4 +/- 39.2 micrograms x h/ml, 8.1 +/- 3.4 h, 3.1 +/- 0.6 micrograms/ml, 18.8 +/- 3.1 ml/min/m2, 3.1 +/- 1.4 ml/min/m2, 9.6 +/- 3.8 l/m2, respectively, which were in accordance with those reported previously in patients treated with etoposide alone. Although concentration at 24 hours, total bilirubin level and total protein level were correlated with the AUC which in turn correlated with hematologic toxicity, the variables were not predictive of hematologic toxicity. We conclude that the concomitant administration of cisplatin at a dose level of 30 mg/m2/day might not affect the pharmacokinetics of prolonged etoposide infusion.