Reconstitution of the F1-ATPase activity from purified alpha, beta, gamma and delta or epsilon subunits with glutathione S-transferase fused at their amino termini

Systems for overexpression and purification of active alpha, beta and gamma subunits of Escherichia coli H(+)-ATPase were established. The alpha and beta subunits recovered as soluble form were purified by hydroxyapatite column chromatography. Since the gamma subunit was overexpressed as the insoluble form, this subunit was purified by polyacrylamide gel-electrophoresis containing sodium dodecyl sulfate. By subsequent denaturation of this subunit with guanidine hydrochloride and renaturation, the active gamma subunit for reconstitution of the F1-ATPase activity with the purified alpha and beta subunit was obtained. The delta and epsilon subunits which were fused to the carboxy terminus of glutathione S-transferase (GST) were overproduced and purified by affinity chromatography. These fused proteins (delta-GST and epsilon-GST) were incubated with the purified alpha, beta and gamma subunits and applied to affinity chromatography. The alpha beta gamma delta-GST and alpha beta gamma epsilon-GST complex were eluted specifically by addition of glutathione and exhibited high and low ATPase activity, respectively, with a subunit stoichiometry similar to that in the native F1-ATPase, indicating that active complexes could be reconstituted with the fused proteins. These results suggested that the amino-terminal ends of the delta and epsilon subunits are not involved in formation of the active complex. The fused epsilon-GST bound the gamma subunit strongly, and the alpha subunit weakly. The delta-GST bound the gamma subunit significantly, and the alpha and beta subunits very weakly.

Acidic catecholamine metabolites and 5-hydroxyindoleacetic acid in urine: the influence of diet

Concentrations of vanillylmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), vanillic acid (VA) and 5-hydroxyindoleacetic acid (5-HIAA) in urine from healthy subjects were determined by a high-performance liquid chromatography system with a mixed-mode (C18/anion-exchange) column and an 8-channel electrochemical detector, in order to study the influence of diet, diurnal variation and age. The urinary excretion of 5-HIAA increased significantly after eating banana, pineapple, tomato, kiwi fruit and walnut. An increase in the urinary excretion of DOPAC and HVA after eating banana and that of VA after taking vanilla was also noted. The urinary excretion of VMA was not significantly influenced by any of the foods examined. The urinary excretion of 5-HIAA in the first-morning urine increased beyond the upper limit of the reference value when banana was taken at 2000 h the previous day. The excretion of all metabolites in the second-morning urine in the fasting state was within respective reference ranges. Diurnal variation of the excretion of VMA, DOPAC, HVA and 5-HIAA in urine was relatively small, but that of VA was large. The concentrations (mmol/mol creatinine) of VMA, DOPAC, HVA, 5-HIAA and VA in the first-morning urine from healthy subjects increased from 7 days after birth to 1 year and then decreased to adult levels at 13 years of age.

Clinical significance of serum concentration of interleukin 8 in patients with bronchial asthma or chronic pulmonary emphysema

Interleukin-8 (IL-8) belongs to the family of chemotactic cytokines and has been shown to activate neutrophils in vitro and in vivo. In this study, we measured IL-8 concentration in the serum of patients with pulmonary emphysema or bronchial asthma. IL-8 concentration in serum of emphysema patients was significantly higher than in asthmatics; in emphysema patients it was significantly correlated with the smoking index and the annual decrease of FEV1.0. In asthmatics IL-8 concentration was below the level of detection, but was markedly increased during exacerbation of asthma. Our findings suggest that IL-8 may be one of the causal factors in these diseases.

Changes in nasal and oral respiratory resistance before and after uvulopalatopharyngoplasty

Twelve patients with complaints of sleep apnea were examined with the all-night sleep test. They underwent uvulopalatopharyngoplasty (UPPP) and were studied with the all-night sleep test again 3 to 6 months after the operation. Nasal and oral respiratory resistance was measured in sitting and supine position before and after surgery using a microrhinograph. The physiological effect of UPPP was also compared with the results of an MRI anatomical study. Nasal and oral respiratory resistance was significantly decreased post-operatively (p <0.05). The decreased value of post-operative nasal respiratory resistance in a supine position was more marked than that of oral resistance, suggesting that UPPP eliminates the obstruction at the soft palate, especially in a supine position. Although our study was performed in awake patients enlargement of the airway in the middle pharyngeal region may improve the nasal and oral respiratory function during sleep.

Relationship between oral breathing and nasal obstruction in patients with obstructive sleep apnea

In 30 normal subjects and 20 patients complaining of snoring or sleep apnea nasal percentage of total respiratory air volume (nasal fraction) was measured when nasal resistance was gradually increased. The switching point from nasal to oral breathing was also examined. Nasal respiratory resistance was measured by a rhinograph, and nasal fraction was measured with an inductive body-plethysmograph and with a CPAP nasal mask when the patients were at rest. Several sizes of cotton pledgets were inserted into the nasal vestibules as obturators, and nasal respiratory resistance and nasal fraction were measured repeatedly until subjects had to breathe through the mouth completely. Although the value of nasal respiratory resistance in patients with complaints of snoring or sleep apnea was higher than that of normal subjects, most of the patients did not complain of a sensation of nasal obstruction. However, the switching point from nasal to oro-nasal breathing in patients with complaints of snoring or sleep apnea was statistically higher than that in normal subjects. These results suggest that patients with complaints of snoring or sleep apnea can easily breathe through the mouth during sleep, and that chronic nasal obstruction may induce obstructive sleep apnea. Therefore, measurements of nasal respiratory resistance and nasal fraction are useful to evaluate obstructive sleep apnea.

[Syphilitic thoracic aortic aneurysm with destruction of vertebral body, producing numbness of lower extremities and paraplegia]

Numbness and paraplegia are uncommon complaints in patient with thoracic aortic aneurysm (TAA). The patient was a 64-year-old man. He suffered numbness and gait disturbance (paraplegia). The blood examination showed no positive findings except a Wassermann was positive. Roentgen examination of the chest showed two abnormal shadows like tumors. The CT and MRI revealed destruction of the vertebral bodies and TAAs adjacent to the spinal cord. After the graft replacement was performed, numbness and paraplegia disappeared. This suggests that in our patient the TAAs destruct the vertebral body and produce pressure on the spinal cord, causing numbness and paraplegia. We experienced a rare case of the syphilitic TAA producing bone destruction, numbness and paraplegia.

[Transjugular intrahepatic portosystemic shunt for upper gastrointestinal bleeding due to portal hypertension: 2-year results]

We performed transjugular intrahepatic portosystemic shunt (TIPS) in 25 patients with liver cirrhosis who developed upper gastrointestinal bleeding due to portal hypertension. The procedure was successful in 23 patients, in whom portal pressure decreased by 51%. Bleeding was stopped in all 5 emergency for whom other treatments, including sclerotherapy, had failed. During the follow-up period (mean: 367 days), shunt dysfunction due to stenosis was observed in 75% of the patients. However, by percutaneous transluminal angioplasty, the patency could be maintained in 85% of the cases after 1 year and 73% of the cases after 2 years. Re-bleeding was observed in 13% of the cases after both 1 and 2 years. Color Doppler ultrasonography was useful for detecting shunt dysfunction. TIPS seems to be an effective treatment of upper gastrointestinal bleeding due to portal hypertension.

Inactivation of cholinesterase by ascorbic acid in the presence of cupric ions: a possible mechanism for the inactivation of an enzyme by the metal-catalyzed oxidation system

The mechanism of inactivation of cholinesterase (EC 3.1.1.8) by the Cu2+ -ascorbic acid (AsA) system was investigated. Incubation of the enzyme with the Cu2+ -AsA system under aerobic conditions resulted in an irreversible loss of enzyme activity. At low concentrations of Cu2+, the extent of inactivation showed the same dependence in accordance with the extent of oxidation of AsA. Saturation kinetics were observed with respect to the concentration of AsA. No change in the dissociation constant of the enzyme-AsA complex was observed at various concentrations of Cu2+. Catalase at a low concentration partially protected the enzyme from the inactivation, but did not affect the oxidation of AsA. In addition, catalase at a high concentration completely protected both the enzyme from inactivation and the AsA from oxidation. Both thiourea and thiocyanate completely protected the enzyme from the inactivation, while AsA was partially oxidized only in the initial phase. Our proposed mechanism for the inactivation of an enzyme by the Cu2+ -AsA system is as follows. A ternary complex involving the enzyme, Cu2+ and AsA is formed. This is followed by a redox reaction within the complex which generates a superoxide (.O2-) and hydrogen peroxide (H2O2). The H2O2 then reacts with .O2- in a Haber-Weiss reaction producing the hydroxyl radical (.OH). Another role of H2O2 is the conversion of the reduced Cu+ within the complex to Cu2+. Thus, repeated cycles of the redox reaction between the Cu2+ and AsA take place at the same locus, producing multiple .OH, which causes its complete inactivation.

Simultaneous determination of catecholamines, their basic metabolites and serotonin in urine by high-performance liquid chromatography using a mixed-mode column and an eight-channel electrochemical detector

A high-performance liquid chromatographic method for simultaneous determination of free catecholamines, their basic metabolites and serotonin in human urine was developed. The compounds were separated on a precolumn of cation-exchange resin and a mixed-mode (C18/cation-exchange) column and determined by an eight-channel electrochemical detector. By this method, free norepinephrine (NE), epinephrine (E), dopamine (DA), normetanephrine (NMN), metanephrine (MN), 3-methoxy-tyramine (3-MT) and serotonin (5-HT) were determined in 40 min with inter-assay precision of 1.9, 3.2, 1.2, 1.6, 1.6, 5.5 and 3.2%, respectively. Detection limits were between 0.05 (E) and 0.3 (3-MT) pmol. The mean values of analytical recovery for NE, E, DA, NMN, MN, 3-MT, 5-HT were 99, 104, 104, 99, 102, 109 and 99%, respectively.

Comparison of bronchodilator responses to adrenomedullin and proadrenomedullin N-terminal 20 peptide

This study was designed to determine and compare airway responses to synthetic human adrenomedullin(AM) and proadrenomedullin N-terminal 20 peptide (PAMP) in anesthetized guinea pigs in vivo. 10(-7) M AM and PAMP significantly inhibited acetylcholine-and histamine-induced bronchoconstriction. However, this significant bronchodilator effect of PAMP lasted about five minutes, which was much shorter than that of AM. In addition, the bronchodilator effect of AM is approximately 100-fold more potent than PAMP. We demonstrated that PAMP had a potent bronchodilator activity, and induced a rapid and short-lasting bronchodilation. These findings suggest that AM and PAMP may play important roles in airway functions.

Determination of medetomidine, atipamezole and midazolam in pig plasma by liquid chromatography-mass spectrometry

Medetomidine, atipamezole and midazolam in pig plasma were determined by liquid chromatography-mass spectrometry (LC-MS) with an atmospheric pressure chemical ionization interface system by the use of detomidine as an internal standard. The method was applied to studies of pharmacokinetic behaviour of these drugs.

Adrenomedullin inhibits the secretion of cytokine-induced neutrophil chemoattractant, a member of the interleukin-8 family, from rat alveolar macrophages

This study was undertaken to determine the effects of adrenomedullin (AM) on the secretion of cytokine-induced neutrophil chemoattractant (CINC), a member of the interleukin-8 family, from lipopolysaccharide-stimulated rat alveolar macrophages in vitro. AM significantly increased cAMP levels in alveolar macrophages in a dose-dependent fashion. On the other hand, AM significantly inhibited CINC secretion from alveolar macrophages in a dose-dependent fashion, and 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) also significantly inhibited CINC secretion. These findings suggest that AM may play important roles in the regulation of airway inflammation via a cAMP-dependent mechanism.

Essential aspartic acid residues, Asp-133, Asp-163 and Asp-164, in the transmembrane helices of a Na+/H+ antiporter (NhaA) from Escherichia coli

The importance of negatively charged residues in transmembrane helices of many cation-coupled transporters has been widely demonstrated. Four Asp residues were located in the putative transmembrane helices of the Escherichia coli Na+/H+ antiporter, NhaA. We replaced each of these Asp residues by Asn in plasmid encoded nhaA and expressed these constructs in an E. coli mutant defective in both nhA and nhaB. Substitution of Asp-65 or Asp-282 (in the extramembrane region) had no effect on supporting the host mutant growth in the high NaCl- or LiCl-containing medium, and these two mutants had normal Na+/H+ and Li+/H+ antiporter activities. In contrast, substitution of Asp-133, Asp-163 or Asp-164 was detrimental to survival of the host mutant and impaired both Na+/H+ and Li+/H+ antiporter activities. These three Asp residues, conserved in the nhaA homologs from different species and which are located closely in the 3rd and 4th putative transmembrane helices, appear to play important roles in cation binding and transport.

Angiotensin II stimulates peptide leukotriene production by guinea pig airway via the AT1 receptor pathway

Angiotensin II (Ang II) regulates a variety of physiological functions, including contraction of smooth muscle. Peptide leukotrienes (LTs) have recently been reported to be potent bronchoconstrictors and may play a role in the pathogenesis of airway inflammation. However, the possibility that Ang II and peptide LTs interact in the control of airway function has not been studied. In this study, we showed that Ang II receptors are present on guinea pig airway, and that they are of the AT1 subtype. We showed the possibility that Ang II induced the release of peptide LTs from guinea pig airway by activation of the AT1 receptor pathway. Our findings thus suggest that interaction between Ang II and peptide LTs might increase airway inflammation in the guinea pig.

[Thoracoscopic treatment of a giant bulla: a case report]

A 38-year-old man was admitted to our hospital because of left giant bulla and pneumothorax. His chest X-rays and CT scan showed giant bulla of the left upper lobe and left pneumothorax. We performed bullectomy using the ENDOPATH ENDO LINEAR CUTTER 60 mm and 35 mm disporsable surgical stapler under thoracoscopic guidance. Clipping with end-clips and fibrin glue were effective for miner air leakage. There were no complications such as prolonged air leakage or incomplete lung re-expansion. His post operative couse was uneventful and he was discharged from the hospital on the 11th post operative day. When performed along with mini-thoracotomy, thoracoscopic operation is useful in treating patients with giant bulla.

Angiotensin II stimulates production of nitric oxide in guinea pig airways via AT1 receptor activation

Angiotensin II (Ang II) and nitric oxide (NO) regulate a variety of physiological functions. In this study, we suggest that inhaled Ang II produces an initial bronchodilation apparently by stimulating NO production via AT1 receptors. Also, we demonstrate that following the initial bronchodilation, Ang II causes bronchoconstriction in the guinea pig, also via AT1 receptors. Both of the findings are important for our understanding of airway functions induced by Ang II.

Enhancement of Escherichia coli H(+)-ATPase caused by binding of monoclonal antibodies is attributed to structural changes of Leu-456 and Ser-440 in the alpha subunit

Five monoclonal antibodies against the alpha subunit of F1-ATPase from Escherichia coli alpha 104, alpha 105, alpha 107, alpha 109, and alpha 110 were prepared. The monoclonal antibodies alpha 104 and alpha 110 enhanced the F1-ATPase activity maximally to 1.6- and 1.7-fold that of the wild-type, respectively, while alpha 105 did not. Both antibodies bound to a peptide corresponding to the region between residues 354 and 513. Mutations in this region which caused reduced binding of the alpha subunit to the antibodies were identified at residues Ser-440, Leu-456, Leu-471, Leu-482, Met-483, and Ser-506 for alpha 104 and residues Ser-440, Leu-456, Leu-471, Asp-476, Leu-482, Met-483, and Ser-506 for alpha 110. These residues are possibly involved in the epitopes for the antibodies and are located close together on the surface of the alpha subunit. Among the mutations, Leu-456 to Pro and Ser-440 to Pro mutations caused increase of the F1-ATPase activity up to 1.9 and 1.2 times that of the wild-type, respectively, while Leu-471 to Pro mutation caused a defect in assembly of the F1-ATPase on the membrane. The other mutations caused no significant change in ATPase activity. These results suggested that Ser-440 and Leu-456 have an important role in regulating catalysis by the F1-ATPase, but that the neighboring residue Leu-471 has an important role in assembly of the F1-ATPase complex. It was also suggested that binding of the monoclonal antibodies alpha 104 and alpha 110 to residues Ser-440 and Leu-456 caused local conformational changes, leading to enhancing effects on F1-ATPase activity similar to the Ser-440 to Pro and Leu-456 to Pro mutations.

Hypothalamic hamartoma: anatomic, immunohistochemical and ultrastructural features

Four patients with hypothalamic hamartoma were examined by CT and/or MR imaging, immunohistochemistry and electron microscopy. The hamartomas arose from the hypothalamus and extended inferiorly. LH-RH neurons were detected in three cases by immunohistochemistry. Electron microscopy revealed large myelinated axons, axon terminals containing dense-core vesicles and axon terminals with clear vesicles forming asymmetrical synapses. The development of hypothalamic hamartoma and its functional manifestations (precocious puberty and laugh attacks) are discussed in reference to the migration of LH-RH neurons from the olfactory placode.

Thrombomodulin in exercise-induced asthma

Thrombomodulin (TM) is a membrane protein present in the vascular endothelium. It has also been found in human plasma, within which, however, its pathological functions have not been clearly described. In this study, the plasma TM concentrations in 19 asthmatic patients were determined by sandwich enzyme immunoassay using two monoclonal antibodies for human TM. The concentration of plasma TM in exercise-induced asthma (EIA)-positive asthmatic patients was significantly increased by exercise challenge. In addition, for these patients a positive correlation was found between the severity of EIA and the degree of change in plasma TM induced by exercise challenge. These findings suggest that the increase in influx of TM into the plasma in EIA-positive asthmatics may be due to generalized pulmonary endothelial damage following exercise challenge.

Portal hypertensive colopathy: endoscopic findings and the relation to portal pressure

Portal hypertensive colopathy (PHC) is a new clinical entity in patients with liver cirrhosis. In this study, colonoscopic findings and clinical features including upper gastrointestinal endoscopy and hepatic hemodynamics were prospectively investigated among 35 PH patients with a hepatic venous pressure gradient (HVPG) of greater than 12 mmHg due to chronic liver diseases. Colonoscopy was also performed in 100 patients without liver disease as non-PH controls. The colonoscopy revealed vascular ectasias, vascular irregularity, vascular dilatation, solitary red spots, diffuse red spots, and hemorrhoids in 26, 32, 30, 25, 10 and 25, respectively, of 35 PH patients compared to 3, 7, 3, 11, 0 and 19, respectively, in controls. PHC was endoscopically diagnosed in 27 of 35 PH patients according to our criteria. These patients with PHC were more frequently associated with esophageal varices and portal hypertensive gastropathy, and had higher HVPG than PH patients without PHC. Portal hypertension is an important factor in the etiology of PHC.

Adrenomedullin, a newly discovered hypotensive peptide, is a potent bronchodilator

The present study was designed to examine the effect of adrenomedullin (AM), a novel vasorelaxant peptide originally isolated from human pheochromocytoma, on histamine- or acetylcholine-induced bronchoconstriction in anesthetized guinea pigs in vivo. AM significantly inhibited acetylcholine-induced bronchoconstriction in a dose-dependent fashion. AM also significantly inhibited histamine-induced bronchoconstriction, but 10(-10) M AM had no significant inhibitory effect on this response. We also found that AM induced a long-lasting bronchodilator response, while isoproterenol induced transient bronchodilation. These preliminary findings suggest that AM may play important roles in airway function.

A critical cytoplasmic domain of the interleukin-5 (IL-5) receptor alpha chain and its function in IL-5-mediated growth signal transduction

Interleukin-5 (IL-5) regulates the production and function of B cells, eosinophils, and basophils. The IL-5 receptor (IL-5R) consists of two distinct membrane proteins, alpha and beta. The alpha chain (IL-5R alpha) is specific to IL-5. The beta chain is the common beta chain (beta c) of receptors for IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytoplasmic domains of both alpha and beta chains are essential for signal transduction. In this study, we generated cDNAs of IL-5R alpha having various mutations in their cytoplasmic domains and examined the function of these mutants by expressing them in IL-3-dependent FDC-P1 cells. The membrane-proximal proline-rich sequence of the cytoplasmic domain of IL-5R alpha, which is conserved among the alpha chains of IL-5R, IL-3R, and GM-CSF receptor (GM-CSFR), was found to be essential for the IL-5-induced proliferative response, expression of nuclear proto-oncogenes such as c-jun, c-fos, and c-myc, and tyrosine phosphorylation of cellular proteins including JAK2 protein-tyrosine kinase. In addition, analysis using chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c suggested that dimerization of the cytoplasmic domain of beta c may be an important step in activating the IL-5R complex and transducing intracellular growth signals.

Topographical relation between serotonin-containing paraneurons and peptidergic neurons in the intestine and urethra

Luminal stimulation of enterochromaffin (EC) cells is known to cause their release of serotonin which in turn may induce a variety of reflexes via mucosal intrinsic neurons. To morphologically support this idea, the present study demonstrates a close topographical relationship between EC cells and nerves, using whole-mount preparations. Beaded nerve fibers containing vasoactive intestinal polypeptide (VIP) were observed in close proximity to serotonin-immunoreactive EC cells in the small and large intestines of the rat and guinea pig; in whole-mount preparations, the VIP nerve fibers appeared to underlie EC cells. This finding correlates with the physiological datum that the intra-arterial infusion of serotonin causes VIP release from the intestine. Canine urethral serotonin cells, a counterpart of the intestinal EC cells, were shown to contact intraepithelial nerves immunoreactive for calcitonin gene-related peptide. The neuroparaneuronal connection in the urethra may play an important role in the serotonin-evoked urethrogenital reflex. Intestinal and urethral serotonin-containing paraneurons, which are sensory in nature, may release serotonin in response to luminal stimuli, and directly activate adjacent peptidergic neurons to initiate the reflex arcs.

Residues interacting with serine-174 and alanine-295 in the beta-subunit of Escherichia coli H(+)-ATP synthase: possible ternary structure of the center region of the subunit

The mutation of serine-174 to phenylalanine that causes a defect in the Escherichia coli F1-ATPase beta-subunit is suppressed by further mutations; Gly-149 to Ser, Ala-295 to Thr, Ala-295 to Pro, or Leu-400 to Gln (Miki, J., Fujiwara, K., Tsuda, M., Tsuchiya, T. and Kanazawa, H. (1990) J. Biol. Chem. 265, 21567-21572). We analyzed the effects of these second site mutations and of a newly identified Asn-158 to Tyr mutation on the activities of the ATPase without the original Ser-174 to Phe mutation. The beta-subunit with each amino acid replacement was expressed in the mutant strain JP17, which does not have a beta-subunit. Cells transformed with the plasmid carrying Ala-295 to Pro mutation alone did not grow on minimal medium agar supplemented with succinate as the sole carbon source, and showed 3% of the wild-type ATPase activity, suggesting that this mutation caused structural alterations affecting the catalytic function of the enzyme. Conversely transformants with other mutations grew well and had higher ATPase activities, suggesting that these mutations did not cause extensive structural alterations. From the transformants with the plasmid carrying the Ala-295 to Pro mutation, seven revertants capable of cell growth on succinate plates were isolated and reversion mutations were identified at residues 140, 159, 166, 171, 172 and 184 of the beta-subunits. The results suggested that Ser-174 and Ala-295 do not necessarily interact directly, but that the regions including these suppression mutation sites close to Ser-174, and Ala-295 interact with each other for the proper functioning of the ATPase. The ternary structure of the region surrounded by the residues which were identified as the reversion mutation sites for Ser-174 to Phe and Ala-295 to Pro mutations is important for the catalytic function of this enzyme.