Guinea pig airway hyperresponsiveness induced by blockade of the angiotensin II type 1 receptor. Role for endogenous nitric oxide

Losartan is the first angiotensin II type 1 (AT1) receptor antagonist to become available for the treatment of hypertension. However, recent reports have revealed several cases of losartan-induced bronchoconstriction. We investigated to determine the mechanism of losartan-induced bronchoconstriction, considering in particular the involvement of endogenous nitric oxide (NO). In this study, we examined the effects of losartan on airway obstruction and endogenous NO production using anesthetized guinea pigs and cultured airway epithelial cells. Five minutes after administration of angiotensin II (Ang II), the bronchoconstriction induced by acetylcholine was not changed. In contrast, Ang II in the presence of losartan caused a significant increase in the acetylcholine responsiveness. Pretreatment with L-N omega-nitroarginine-methylester (L-NAME) potentiated acetylcholine-induced bronchoconstriction 5 min after administration of Ang II, and L-arginine reversed this action of L-NAME on the acetylcholine responsiveness. Moreover, Ang II administration increased NO concentration in expired air (12.5 +/- 1.5 ppb for saline, 40 +/- 5 ppb for Ang II, p < 0.01), and losartan significantly inhibited Ang II-stimulated NO release (20 +/- 3.5 ppb) from guinea pig airway. In cultured airway epithelial cells, Ang II also increased NO release (160 +/- 25 nM), and the effect of this Ang II-induced NO release was significantly inhibited by pretreatment with losartan (25 +/- 8 nM, p < 0.01). These findings suggest that losartan-induced bronchoconstriction may result from inhibition of endogenous NO release in the airway.

Subthreshold concentration of endothelin-1-enhanced, capsaicin-induced bronchoconstriction in anaesthetized guinea-pigs

An increasing number of studies have been performed to address a possible role for endothelin-1 (ET-1) as a significant mediator in asthma. However, the effects of subthreshold concentrations of ET-1, which cannot elicit bronchial smooth muscle contraction itself, in asthma has yet to be determined. This study determined these effects of ET-1 on capsaicin-induced bronchoconstriction in anaesthetized guinea-pigs. Aerosolized ET-1 administered at doses of 10(-9) M and higher induced a dose-dependent increase in pulmonary resistance, but ET-1 at 10(-10) M did not have any bronchoconstrictive effect. However, this subthreshold concentration of ET-1 potentiated capsaicin-induced bronchoconstriction. In addition, the potentiation of capsaicin-induced bronchoconstriction by this subthreshold concentration of ET-1 was completely abolished by BQ788 (ET(B) receptor antagonist), but not BQ123 (ET(A) receptor antagonists). Immunoreactive substance P (SP) levels in bronchoalveolar lavage fluid after capsaicin administration were significantly higher than those after solvent administration. However, ET-1 alone did not significantly stimulate immunoreactive SP release and ET-1 (10(-10) M) did not potentiate capsaicin-induced immunoreactive SP release. In contrast, ET-1 (10(-10) M) potentiated exogenous neurokinin A- and SP-induced bronchoconstriction. These findings suggest that a subthreshold concentration of endothelin-1 does not potentiate the tachykinin release induced by capsaicin but the airway smooth muscle contraction through endothelin-B receptors.

pH-dependent growth retardation of Escherichia coli caused by overproduction of Na+/H+ antiporter

The overproduction of Na+/H+ antiporter NhaA in Escherichia coli caused growth retardation. Quantities and the activity of the antiporter were studied for their causative roles in terms of this retardation. We constructed a series of nhaA-expression plasmids differing in their transcriptional and translational efficiencies. Low-level nhaA expression complemented the defect of an nhaA mutant and allowed the mutant to survive on a high-NaCl or high-LiCl medium. However, when the production of NhaA was strongly induced by the combination of a stronger promoter, an efficient translational initiation signal and a high copy number plasmid, the growth of the cells carrying the plasmid was severely retarded. This growth retardation correlated well with the amount of NhaA protein produced from the plasmids. Surprisingly, the growth retardation caused by overproduction of NhaA was enhanced more extensively at an alkaline pH than at a neutral pH, in which the antiporter activity was stimulated. However, these retardations were also observed for mutant NhaA antiporters without the activity. These results indicated that the growth retardation was due to an overproduction of the antiporter rather than its increased antiporter activity, and also affected by a pH-dependent change in NhaA, possibly its structural change.

Increased production of endogenous nitric oxide in patients with bronchial asthma and chronic obstructive pulmonary disease

BACKGROUND

Nitric oxide (NO) plays an important role as an inflammatory mediator in the airways. Though direct measurement of endogenous NO has been difficult in humans, we have recently found that measurement of NO derivatives in induced sputum may be useful for assessing airway inflammation in asthmatic patients.

OBJECTIVE

This study was designed to determine the direct in vivo evidence of increased production of endogenous NO in patients with bronchial asthma and chronic obstructive pulmonary disease (COPD).

METHODS

We have investigated simultaneous assessment of NO using two non-invasive methods, such as NO level in exhaled air and induced sputum, in these patients. We determined the concentration of stable end-products of NO (nitrite plus nitrate) in induced sputum and exhaled NO concentration using a chemiluminescence analyser in 10 normal controls, 10 asthmatic patients and 11 patients with COPD, and evaluated whether endogenous NO levels correlate with percentage of neutrophils and interleukin-8 (IL-8) level in induced sputum in patients with COPD.

RESULTS

We found significantly higher concentrations of exhaled NO in patients with bronchial asthma (25.1 [5.1] p.p.b.) than in patients with COPD (12.1 [1.9] p.p.b.) and normal controls (5.2 [1.4] p.p.b.). However, higher concentrations of NO derivatives in induced sputum were found in patients with bronchial asthma (1190 [106] micromol/L) and COPD (950 [105] micromol/L) than in normal controls (514 [30] micromol/L). In patients with asthma, but not in those with COPD, concentrations of NO derivatives in induced sputum were significantly correlated with concentrations of exhaled NO (r = 0.64, P < 0.05). Moreover, in patients with COPD, concentrations of NO derivatives in induced sputum were significantly correlated with percentage of neutrophils (r = 0.71, P < 0.05) and IL-8 level (r = 0.80, P < 0.01).

CONCLUSION

We conclude the increased production of endogenous NO in patients with asthma and COPD, and that NO derivatives in induced sputum are more valuable than exhaled NO in assessing airway inflammation in patients with COPD.

Severity of exercise-induced bronchoconstriction is related to airway eosinophilic inflammation in patients with asthma

Exercise-induced bronchoconstriction (EIB) is widely prevalent in asthmatic patients. Eosinophilic airway inflammation is considered to be a major factor in the pathogenesis of asthma. However, the effects of eosinophilic airway inflammation on EIB have been elucidated insufficiently. To examine the relationship between the severity of EIB and eosinophilic inflammation, sputum induction and exercise challenge were performed in 21 asthmatic patients. Significantly higher percentages of eosinophils and levels of eosinophil cationic protein (ECP) were found in induced sputum in EIB-positive asthmatics (median (range), eosinophils: 23.5 (11.0-61.0)%; ECP: 1,475 (74.8-17,701) ng x mL(-1)) than in EIB-negative asthmatics (eosinophils: 6.0 (1.0-41.5)% (p=0.006); ECP: 270.6 (10.8-7,700) ng x mL(-1) (p=0.049)). There was a significant correlation between the severity of EIB and the sputum eosinophil percentage (r=0.59, p=0.009) and the level of ECP (r=0.47, p=0.037). The area under the curve of the forced expiratory volume in one second for 30 min after exercise correlated with the percentage of eosinophils (r=0.60, p=0.008) and the level of ECP (r=0.45, p=0.04). There was no correlation between airway responsiveness to methacholine on the one hand and EIB, sputum eosinophils or ECP on the other. In conclusion, these results provide evidence that the severity of bronchoconstriction evoked by exercise is more closely related to eosinophilic airway inflammation than airway hyperresponsiveness to methacholine in asthmatic patients.

Clinical implication of protein levels of IL-5 in induced sputum in asthmatic patients

To determine whether protein levels of interleukin-5 (IL-5) in induced sputum reflect the degree of eosinophilic inflammation, we evaluated the role of IL-5 on clinical characteristics in stable asthmatic patients. IL-5 level, differential eosinophil count, and level of eosinophil cationic protein (ECP) in induced sputum were all significantly higher for asthmatics than for normal controls. Both eosinophil counts and ECP levels in induced sputum were inversely correlated with the degree of airflow limitation (FEV1/FVC). In addition, patients with measurable IL-5 in sputum had significantly more eosinophils, higher levels of ECP in sputum, and lower FEV1 (percent predicted) than did patients with levels of IL-5 beneath the limit of detection. However, we found no significant difference in IL-5 levels between atopic and nonatopic asthmatics. IL-5 level in induced sputum is a good indicator of eosinophilic inflammation in atopic and nonatopic asthmatic patients.

Effects of transjugular intrahepatic portosystemic shunt (TIPS) on esophageal motor function and gastroesophageal reflux

The effects of transjugular intrahepatic portosystemic shunt (TIPS) placement on esophageal motor function and gastroesophageal reflux were investigated in patients with esophageal varices. In six men with esophageal varices, esophageal manometry and upper gastrointestinal endoscopy were performed before and 15-20 days after TIPS placement. Intraesophageal pH monitoring was performed in the four patients with severe esophageal varices (defined as the largest sized varices) following TIPS placement. Findings were compared with those in six healthy men (controls) who underwent esophageal manometry and intraesophageal pH monitoring. The esophageal varices resolved or were reduced after TIPS placement. Resting lower esophageal sphincter (LES) pressures were similar in the study group before and after TIPS placement and in the control subjects. The incidence and progression of esophageal contractions were similar in the study group before and after TIPS placement and in the control subjects. At 3 cm above the LES, the amplitude of esophageal contraction after TIPS placement was significantly higher than that before TIPS placement. At 3 and 8 cm above the LES, the amplitude of esophageal contraction in the control subjects was significantly higher than that in the study group before and after TIPS placement. Esophageal acid exposure time after TIPS placement was similar to that in the controls. TIPS placement is a useful treatment that improves esophageal motor function without the occurrence of pathologic gastroesophageal reflux.

Inhibitory action of spinorphin, an endogenous regulator of enkephalin-degrading enzymes, on carrageenan-induced polymorphonuclear neutrophil accumulation in mouse air-pouches

Whether spinorphin, an endogenous regulator of enkephalin-degrading enzymes, plays a role in an anti-inflammatory action was examined, using a mouse air-pouch assay as a model of acute inflammation. Repeated intravenous administration (6 times) of spinorphin every hour significantly suppressed carrageenan-induced polymorphonuclear neutrophil (PMN) accumulation, an indicator of inflammation (3.21+/-0.95 x 10[6] cells vs 8.92+/-0.96 x 10[6] cells, 10mg/kg spinorphin-treated vs saline-treated group, n=5, P<0.01) at 6 hr. The combination of spinorphin and leuhistin (2 mg/kg, i.v.), a specific inhibitor of aminopeptidase N (APN), markedly suppressed the PMN accumulation induced by carrageenan (1.11+/-0.17 x 10[6] cells, 88% inhibition compared to the saline-treated group, n=5, P<0.01). This inhibition was less than, but comparable to that of dexamethasone (30 mg/kg/one shot, i. v.), a representative anti-inflammatory drug. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator, its inhibitory activity being modulated by APN.

CYFRA 21-1, a cytokeratin subunit 19 fragment, in bronchoalveolar lavage fluid from patients with interstitial lung disease

1. It has been suggested that CYFRA21-1, a cytokeratin subunit 19 fragment, is potentially useful for diagnosis and monitoring of lung carcinoma. However, serum levels of CYFRA21-1 are also increased in a high proportion of patients with interstitial lung disease. In this study we measured CYFRA21-1 levels in bronchoalveolar lavage fluid from 10 normal subjects, 18 patients with idiopathic pulmonary fibrosis and 14 patients with sarcoidosis, and determined whether any relationship exists between CYFRA21-1 levels in bronchoalveolar lavage fluid and clinical parameters. 2. CYFRA21-1 levels in bronchoalveolar lavage fluid were significantly higher in patients with sarcoidosis (mean value 8.3 ng/ml, P < 0.01) and idiopathic pulmonary fibrosis (42.5 ng/ml, P < 0.005) than in normal controls (1.0 ng/ml). Moreover, higher CYFRA21-1 levels in bronchoalveolar lavage fluid were found in sarcoidosis patients in radiological stage 2 or 3 than in those in stage 1. In patients with idiopathic pulmonary fibrosis, there was a significant correlation between CYFRA21-1 levels, and percentage of inflammatory cells in bronchoalveolar lavage fluid (r = 0.56, P < 0.05) and the magnitude of the alveolar--arterial oxygen pressure difference [P(A-a)O2] gradient (r = 0.66, P < 0.01). 3. Serial bronchoalveolar lavage samples were obtained from six patients with clinically active pneumonitis after they had undergone systemic corticosteroid therapy. CYFRA21-1 levels were significantly lower after these patients exhibited clinical improvement (P < 0.05). 4. These findings suggest that the level of CYFRA21-1 in bronchoalveolar lavage fluid is a useful marker for the clinical diagnosis of pneumonitis, and is also adequate for the evaluation of disease activity, especially over the course of treatment.

Reconstitution of F1-ATPase activity from Escherichia coli subunits alpha, beta and subunit gamma tagged with six histidine residues at the C-terminus

An engineered gamma subunit of Escherichia coli F1-ATPase with extra 14 and 20 amino acid residues at the N- and C-termini (His-tag gamma), respectively, was overproduced in E. coli and purified. Six histidines are included in the C-terminal extension. The reconstituted F1 containing alpha, beta, and His-tagged gamma exhibited sixty percent of the wild-type ATPase activity. The reconstituted alphabeta His-tag gamma complex was subjected to affinity chromatography with nickel-nitrilotriacetic acid (Ni-NTA) agarose resin. ATPase activity was eluted specifically with imidazole. These results implied that the tag sequence protruded to the surface of the complex and did not seriously impair the activity. The reconstituted alphabeta His-tag gamma complex, even after its binding to the resin, exhibited ATPase activity suggesting that the gamma subunit, when fixed to a solid phase, may rotate the alphabeta complex. This system may provide a new approach for analysis of the rotation mechanisms in F1-ATPase.

[Traumatic aortic regurgitation: report of two surgical cases]

Two successful surgical cases with aortic regurgitation due to blunt trauma are reported. Case 1: A 48-year-old female was transferred to our hospital after a traffic accident. She was intubated and mechanically ventilated. Twelve days later, echocardiography demonstrated massive aortic regurgitation. The next day, aortic valve replacement was performed using a 21 mm SJM mechanical valve. The central part of the non-coronary cusp was torn and perforated 15 mm long. She is in good condition three years after surgery. Case 2: A 57-year-old male was transferred to the nearest hospital because he was involved in a snowslide accident. A month after the injury, catheterization showed massive aortic regurgitation and pulmonary hypertension. An aortotomy revealed that the intima around the right coronary ostium was completely torn. A perforation with a diameter of 3 mm was also observed on the right coronary cusp. After coronary cusps were excised, interrupted mattress sutures buttressed with pledgets were passed through the aortic wall at the distal level of the intimal laceration and then to the aortic annulus. A 25 mm SJM prosthetic valve was seated at the aortic ring. As the right coronary ostium was included in the plicated aortic wall, aortocoronary bypass was constructed using the great saphenous vein. He is doing well 14 months after surgery. Aortic regurgitation due to blunt trauma is rare and difficult to diagnose. Sometimes cardiac failure progresses rapidly. Therefore, urgent surgery is recommended as soon as the diagnosis is confirmed.

A novel MR angiography technique: SPEED acquisition using half-Fourier RARE

A novel MR angiography (MRA) method, swap phase encode extended data (SPEED), was developed. Two one-shot images with the phase-encode directions swapped were collected within a single breath-hold period and processed with a maximum intensity projection (MIP) to obtain an image. In this study, a long echo train two-dimensional rapid acquisition with relaxation enhancement (RARE) sequence with half-Fourier (half-RARE) was used to obtain the pulmonary MRA images. The MIP image obtained using the SPEED technique presented promising results for pulmonary vessels.

[Transjugular intrahepatic portosystemic shunt for the treatment of refractory ascites]

Five cirrhotic patients with refractory ascites were treated with transjugular intrahepatic portosystemic shunt (TIPS). Before TIPS, although patients were received salt restriction (5 g/day), diuretic therapy (furosemide 112 mg/day, spironolactone 140 mg/day), albumin infusion and paracentesis, ascites did not show improvement. After TIPS, urine volume and urinary sodium excretion increased significantly. Mean body weight decreased significantly from 73 kg before TIPS to 63 kg a month after TIPS. Improvement of ascites after TIPS were associated with a significant reduction in the dose of diuretics. On discharge, complete resolution of ascites was found in 2 patients and mild ascites remained in 3 other patients. Four patients presented 6 episodes of shunt stenosis in the follow-up period, and were treated with balloon dilatation. Ascites increased on shunt dysfunction and showed improvement after balloon dilatation. Post-TIPS encephalopathy was seen in 2 patients and one of 2 was disabled. In conclusion, although post-TIPS shunt dysfunction and encephalopathy are common. TIPS is an effective therapy for refractory ascites in patients with cirrhosis.

An autopsy case of peripheral neuroepithelioma in posterior mediastinum with p53 point mutation

An 18-year old male was admitted to our hospital complaining of back pain. His chest computed tomography showed a tumor in the posterior mediastinum. Open biopsy was performed, and a diagnosis of peripheral neuroepithelioma was made. No genetic abnormalities were detected in the DNA obtained from the biopsy specimen. He received chemotherapy and radiation several times. These treatment regimens were effective, but he relapsed 14 months later and died of respiratory failure due to tumor growth. Autopsy examination revealed a large tumor which occupied almost the entire right thoracic cavity, but there was no evidence of metastasis to other organs. Chromosomal translocation t(14;17) (q24;p12.2) and point mutation of exon 5 of the p53 gene were detected.

Determination of sedatives and anesthetics in plasma by liquid chromatography-mass spectrometry with a desalting system

Though liquid chromatography-mass spectrometry (LC-MS) is a powerful tool for analysis of drugs and their metabolites, it does not allow the use of a non-volatile buffer such as phosphate buffer. We used a column-switching desalting system in combination with atmospheric pressure chemical ionization LC-MS for analysis of sedatives and anaesthetics. The drugs examined were flumazenil, butorphanol, midazolam, lorazepam, phenobarbital and flunitrazepam. The separation was carried out on a reversed-phase column using acetonitrile-0.1 M phosphate buffer as a mobile phase. The mass spectra are almost the same as those obtained by direct analysis and the molecular ions were clearly observed. In the analysis, phosphate buffer was completely removed with the trapping column and did not interfere with ionization of the drugs in MS. The chiral separation of lorazepam was achieved on a chiral column with UV, optical rotatory detection and MS. This method is sufficiently sensitive and accurate for the pharmacokinetic studies of these drugs in biological samples.

Subunit interactions of Escherichia coli F1-ATPase: mutants of the gamma subunits defective in interaction with the epsilon subunit isolated by the yeast two-hybrid system

Previously, we established a method to detect subunit interactions of F1-ATPase by the yeast two-hybrid system (Moritani, C., et al. Biochim. Biophys. Acta 1274, 67-72, 1996). Here, we isolated mutants of the gamma subunits defective in interaction with the epsilon subunit by this new procedure to study the molecular basis of coupling mechanisms of the F1F0-ATPase. Based on the intensities of the reporter gene expression in this system, five mutants of the gamma subunit with different levels of gamma-epsilon interactions were isolated and their single base substitutions were determined. Mutants with a substitution of Pro-55 for Leu, Thr-102 for Met, Val-141 for Asp, or Gln-235 for Leu exhibited decreased reporter gene expression, suggesting decreased levels of interaction, while Asp-85 for Gly mutation caused a higher level of expression, suggesting increased interaction. Among these point mutations, G85D, M102T, or D141V mutations were introduced into the gamma subunit gene in the plasmid carrying whole unc operon. Transformants carrying a deletion mutant of the whole unc operon with these expression plasmids were analyzed. Mutations M102T and D141V with decreased gamma-epsilon interaction caused increases of membrane-bound F1-ATPase activity and proton pumping activity, while G85D with increased gamma-epsilon interaction exhibited lower levels of F1-ATPase activity in the membranes. Molecular assembly of the F1 subunits on the mutant membranes detected by Western blotting exhibited no defect for all three mutants. These results suggested that the correlation between the ATPase activity and gamma-epsilon interaction is reciprocal and this interaction may regulate the ATPase activity. The topological and functional importance of Gly-85, Met-102, and Asp-141 together with Leu-55 and Leu-235 in gamma-epsilon interaction is discussed.

Gin4 of S. cerevisiae is a bud neck protein that interacts with the Cdc28 complex

BACKGROUND

A number of proteins make up the Cdc28 complex in Saccharomyces cerevisiae, and regulate CDK activity. The cell cycle regulator Nik1 (Hsl1) is a protein kinase that interacts with the Cdc28 complex. The growth inhibitor Gin4 is structurally similar to Nik1 and may play a redundant role in the regulation of the cell cycle. We investigated the functions of Gin4 with respect to those of Nik1.

RESULTS

GIN4 was not essential for growth, and cells deficient in the GIN4 gene displayed no obvious defects in cell cycle regulation. The delta(gin)4 delta(nik)1 strain was temperature sensitive and showed an abnormal cell shape and FACS profile at permissive temperatures. GFP-fused Gin4 was localized at the bud-neck from late G1 to the M phase. Over-production of the C-terminal portion of Gin4 was toxic for cell growth, and this domain was required for the bud-neck localization of Gin4-GFP. High copy expression of Gin4-GFP disturbed the bud-neck localization of Gin4 in the abnormally elongated cells. Cytokinesis was defective in the delta(gin)4 cdc28 double mutants. The GST-Gin4 fusion protein physically associates with the Cdc28 complex.

CONCLUSIONS

Gin4 is a bud-neck protein. GIN4 and NIK1 have distinct but partially overlapping functions. The major function of GIN4 is to ensure proper mitotic progression and cytokinesis.

Interaction of the delta and b subunits contributes to F1 and F0 interaction in the Escherichia coli F1F0-ATPase

Interactions of the F1F0-ATPase subunits between the cytoplasmic domain of the b subunit (residues 26-156, bcyt) and other membrane peripheral subunits including alpha, beta, gamma, delta, epsilon, and putative cytoplasmic domains of the a subunit were analyzed with the yeast two-hybrid system and in vitro reconstitution of ATPase from the purified subunits as well. Only the combination of bcyt fused to the activation domain of the yeast GAL-4, and delta subunit fused to the DNA binding domain resulted in the strong expression of the beta-galactosidase reporter gene, suggesting a specific interaction of these subunits. Expression of bcyt fused to glutathione S-transferase (GST) together with the delta subunit in Escherichia coli resulted in the overproduction of these subunits in soluble form, whereas expression of the GST-bcyt fusion alone had no such effect, indicating that GST-bcyt was protected by the co-expressed delta subunit from proteolytic attack in the cell. These results indicated that the membrane peripheral domain of b subunit stably interacted with the delta subunit in the cell. The affinity purified GST-bcyt did not contain significant amounts of delta, suggesting that the interaction of these subunits was relatively weak. Binding of these subunits observed in a direct binding assay significantly supported the capability of binding of the subunits. The ATPase activity was reconstituted from the purified bcyt together with alpha, beta, gamma, delta, and epsilon, or with the same combination except epsilon. Specific elution of the ATPase activity from glutathione affinity column with the addition of glutathione after reconstitution demonstrated that the reconstituted ATPase formed a complex. The result indicated that interaction of b and delta was stabilized by F1 subunits other than epsilon and also suggested that b-delta interaction was important for F1-F0 interaction.

Exchangeability of the b subunit of the Cl(-)-translocating ATPase of Acetabularia acetabulum with the beta subunit of E. coli F1-ATPase: construction of the chimeric beta subunits and complementation studies

The gene encoding the b subunit of the Cl(-)-translocating ATPase (aclB) was isolated from total RNA and poly(A)+ RNA of Acetabularia acetabulum and sequenced (total nucleotides of 3038 bp and an open reading frame with 478 amino acids). The deduced amino acid sequence showed high similarity to the beta subunit of the F type ATPases, but was different in the N-terminal 120 amino acids. The role of the N-terminal region was investigated using an F -ATPase beta-less mutant of E. coli, JP17. The JP17 strain expressing the aclB could not grow under conditions permitting oxidative phosphorylation, although ACLB was detected in the membrane fraction. The beta subunit was divided into three portions: amino acid position from 1 to 95 (portion A), 96 to 161 (portion B) and 162 to the C-terminus (portion C). The corresponding regions of ACLB were designated as portions A' (from 1 to 106), B' (from 107 to 172) and C' (from 173 to 478). Chimeric proteins with combinations of A-B'-C', A-B-C' and A'-B-C restored the function as the beta subunit in E. coli F0F1-complex, but those with combinations of A'-B'-C and A-B'-C had no function as the beta subunit. These findings suggested that portion B plays an important role in the assembly and function of the beta subunit in the F0F1-complex, while portion B' of ACLB exhibited inhibitory effects on assembly and function. In addition, portion A was also important for interaction of the beta subunit with the alpha subunit in E. coli F0F1-complex. These findings also suggested that the b subunit of the Cl(-)-translocating ATPase of A. acetabulum has a different function in the Cl(-)-translocating ATPase complex, although the primary structure resembled to the beta subunit of the F1-ATPase.

[Aortic arch replacement performed in emergency in a short-term after grafting for abdominal aortic aneurysm]

Two cases of successful staged replacement of multiple aortic aneurysms are reported. Case 1: A 65-year-old man was found to have abdominal aortic and aortic arch aneurysms. He underwent abdominal aneurysmectomy and Y-grafting in the first stage. A month after his discharge, he was transferred to our hospital because of abrupt chest pain. Two days later, he fell into shock and emergent aortic arch replacement was performed successfully. Case 2: A 46-year-old man was transferred to our hospital because of abrupt abdominal pain and shock. CT scan revealed the rupture of the abdominal aneurysm. He received emergent abdominal aneurysmectomy and Y-grafting successfully. Three months later, he was readmitted because of back pain. CT scan revealed DeBakey Type I dissecting aneurysm. After three days, PaO2 of blood gas analysis fell to 46 mmHg, and absent femoral pulsation and oliguria were also observed. Therefore, aortic arch replacement was performed in emergency. The intimal tear was found in the distal aortic arch. The both of cases are doing well 24 months and 10 months after surgery respectively. It is important to scrutinize the order of surgery for multiple aortic aneurysms and to control blood pressure properly after aneurysmectomy.

Closure of a ventricular septal defect in a patient with von Willebrand disease

Few reports of open heart surgery being performed in patients with von Willebrand disease (vWD) have been documented. We describe herein the case of a 5-year-old girl with a ventricular septal defect (VSD) and vWD who underwent patch closure under cardiopulmonary bypass (CPB). The hematological parameters relating to vWD, namely, factor VIII, von Willebrand factor, and factor VIII-related antigen were monitored perioperatively. These laboratory findings were elevated after the termination of CPB, and consistently maintained within the normal range for 4 months postoperatively. The operation was successfully completed without the administration of factor VIII concentrates or homologous blood products.

Occurrence of subtypes of gustatory cells in cat circumvallate taste buds

Transmission-electron microscopy of cat taste buds confirmed that, as in other mammals, each taste bud comprised four distinct types of cells: Type I, Type II, Type III (gustatory), and Type IV (basal) cells. Gustatory cells made synaptic contacts with nerves to which synaptic vesicles were gathered. The following are the main findings on the cat gustatory cells: 1) The synaptic vesicles of gustatory cells were essentially all dense-cored in type; small clear vesicles, which usually are intermingled in other mammals, could not be found. 2) The vesicles were accumulated not only in the synaptic area but also in the basal cytoplasm. This implies endocrine and paracrine functions. 3) On the basis of the fine structure of the vesicles, two subtypes of gustatory cells were discriminated. A large part of the cells contained vesicles measuring about 180 nm in diameter, while a small part had smaller ones of about 100 nm in diameter. This is the first demonstration of a dual population of gustatory cells in mammals, suggesting different messenger substances utilized.

[Relationship between exercise-induced hypoxemia and long-term survival in patients with chronic obstructive pulmonary disease]

In patients with chronic obstructive pulmonary disease (COPD), exercise-induced hypoxemia (EIH) is an important limiting factor of exercise performance, but there are very few reports of the prognostic value of EIH. We therefore examined whether EIH is related to long-term outcome in patients with COPD. We gathered data on survival of 77 patients with COPD who had undergone three-minute incremental treadmill exercise tests between 1979 and 1988. A plastic catheter was placed percutaneously into a brachial artery to measure arterial blood gases at each stage of exercise. Expired gas was analyzed continuously during exercise with a Respiromonitor RM-300 (Minato Medical Science). As an index of the severity of EIH we used the delta PaO2/delta VO2 (mmHg/L/min), PaO2-slope. Patients were assigned to two groups according to PaO2-slope, and actuarial survival curves were plotted for the two groups. The survival data were analyzed by generalized Wilcoxon analysis. Survival was significantly better in the group with low PaO2-slopes (< 20 mmHg/L/min) than in the group with high PaO2-slopes (> or = 20 mmHg/ L/min) (p = 0.0031). Also, among the patients in whom PaO2 during exercise was less than 60 mmHg, there was a significant difference in survival between those who received home oxygen therapy and those who did not. We conclude that the degree of EIH can be used to predict survival in patients with COPD, and that the degree of EIH should be considered when prescribing continuous home oxygen therapy for these patients.