Endothelin-2-converting enzyme from human renal adenocarcinoma cells is a phosphoramidon-sensitive, membrane-bound metalloprotease

From the membrane fraction of cultured human renal adenocarcinoma (ACHN) cells, two endothelin-2-converting enzymes (ECE-2A and ECE-2B) were solubilized with detergent Lubrol PX and separated by hydrophobic butyl fast-performance liquid chromatography. The pH range of the converting activity of ECE-2B for big endothelin-1 (big ET-1), big ET-2, or big ET-3, was very narrow, and the optimal pH for each substrate was significantly different; the pH optimum for big ET-1 was 6.8 and that for big ET-2 or big ET-3 was 6.4. The ET-converting activity was abolished by phosphoramidon, 1,10-phenanthroline and EDTA but was not inhibited by thiorphan, E-64, leupeptin, PCMS, p-APMSF, or pepstatin A. The conversion efficiency for big ET-2 or big ET-3 by ECE-2B was approximately one-eighth of that for big ET-1. The molecular weight of ECE-2B was estimated to be 400 kDa by gel filtration. Because these characteristics of ECE-2B are very similar to those of ET-1-converting enzyme (ECE-1) in endothelial cells, these results raise the possibility that ECE-2B is identical to ECE-1 and that a single ECE physiologically converts all big ETs to the corresponding ETs in ET-producing cells.

[A case of primary cardiac amyloidosis with amyloid A protein]

A case of cardiac amyloidosis in a 46-year-old male is reported. He was admitted for dyspnea. Physical examination revealed third and forth heart sound and hepatomegaly. Radiographic heart-thoracic ratio was 53%. Electrocardiogram showed first degree A-V block, rS pattern in V1-V4 leads, and ambulatory electrocardiogram showed ventricular tachycardia. Echocardiogram revealed hypertrophy and highly refractile echoes of the left ventricular wall. Endomyocardial biopsy was performed and it demonstrated amyloid fibrils, which were characterized immunohistochemically as Amyloid A (AA) protein, which is generally a constituent in secondary amyloidosis. Urine protein electrophoresis showed lambda type Bence-Jones protein, but bone marrow biopsy was normal. There was no evidence of malignancy, chronic inflammatory disease, or collagen disease. This case was diagnosed as primary amyloidosis with AA protein. It is rare that, in spite of its being a case of primary amyloidosis, its constituent protein is AA protein.

Effect of phosphoramidon on big endothelin-2 conversion into endothelin-2 in human renal adenocarcinoma (ACHN) cells. Analysis of endothelin-2 biosynthetic pathway

The biosynthetic pathway of endothelin (ET)-2 was analyzed in cultured ACHN cells. In the supernatant, we detected three ET-2-related peptides, ET-2, big ET-2(1-38) and big ET-2(22-38). Phosphoramidon decreased the amount of ET-2 and increased that of big ET-2(1-38) dose-dependently. The amount of big ET-2(1-37) did not significantly change. These results suggest that big ET-2 is composed of 38 and not 37 amino acid residues, and that a putative ET-2-converting enzyme (ECE-2) should be classified as a phosphoramidon-sensitive neutral metalloprotease, bearing a resemblance to the putative ET-1-converting enzyme (ECE-1) in endothelial cells.

Identification of an upstream regulatory region essential for cell type-specific transcription of the pro-alpha 2(V) collagen gene (COL5A2)

The transcriptional features of the human alpha 2(V) collagen gene (COL5A2) were examined by transfection experiments coupled to various DNA binding assays. This approach identified an upstream region essential for the cell type-specific expression of the COL5A2 promoter. Within this region are two nuclear factor-binding sites, FP-A and FP-B, responsible for the formation of distinct DNA-protein complexes. Mutations introduced across each of the two binding sites eliminated the formation of the cognate complex and decreased promoter activity by about 3-fold (FP-A) and 40-fold (FP-B) in transfection experiments. Competition experiments using recognition sequences for known transcription factors exhibiting some similarity to the FP-A- and FP-B-binding sites failed to inhibit COL5A2/protein interactions. Thus, COL5A2 expression appears to be under the positive control of a short regulatory sequence likely to harbor two novel nuclear factor-binding sites.

Clearance of HBsAg in seven patients with chronic hepatitis B

The natural history of chronic hepatitis B patients who spontaneously cleared serum HBsAg was investigated. A total of 351 patients with chronic hepatitis B were observed in our hospital for at least 3 yr. Seven of these patients became HBsAg negative during the follow-up period. HBsAg disappeared within 6 mo (range = 11 to 169 days, mean = 70 days) after acute elevation of ALT. ALT levels as high as 500 IU were found in three patients, whereas such elevation was not demonstrated in the other four patients. After the disappearance of HBsAg, ALT levels returned to normal in all patients. With one exception, all patients seroconverted to antibody to HBsAg; however, hepatitis B virus DNA remained detectable in serum using the polymerase chain reaction in five patients. The titer of percent inhibition of antibody to HBcAg gradually decreased to less than 70% when a 1:200 dilution of the serum of six patients was used. Four of the patients had active liver disease develop: two had chronic active hepatitis and two had cirrhosis. Three of these four patients subsequently had hepatocellular carcinoma develop. These findings suggest that patients may suffer complications of chronic hepatitis even after normalization of transaminase activities and after the clearance of HBsAg. Thus hepatitis B virus should be considered as a possible factor associated with hepatocellular carcinoma even in the absence of HBsAg, particularly if serum hepatitis B virus DNA persists.

Evaluation of morphological changes of the atherosclerotic aorta by enhanced computed tomography

Enhanced and non-enhanced computed tomography (CT) were performed in 405 subjects (222 men; 183 women; mean age 57 years). Intimal atherosclerotic changes of the aorta were quantified by enhanced CT, revealing the atheromatous intima to be projecting and thick-walled, while non-enhanced CT demonstrated aortic calcification. We measured the degree of aortic intimal changes at various segments of the aorta. In 224 cases, CT was performed from the aortic root to the bifurcation of the abdominal aorta. Intimal changes were found predominantly at the aortic arch, the middle descending thoracic and the infrarenal abdominal aorta. As for the intimal changes, aortic calcification and aortic pulse wave velocity were significant atherosclerotic characteristics. The aortic diameter did not show a significant association with intimal change. Among the various atherosclerotic risk factors, intimal change was significantly associated with age, systolic blood pressure, serum total cholesterol and diabetes mellitus, whereas gender, diastolic blood pressure, relative weight and cigarette use were not significantly related. For coronary artery disease and arteriosclerosis obliterans, aortic intimal changes constituted a significant atherosclerotic feature. In cerebrovascular disease, however, aortic intimal change did not play a significant role.

[Usefulness of 18F-fluorodeoxyglucose positron emission tomography for evaluating myocardial viability in old myocardial infarction]

The purpose of this study is to compare the characteristics of images obtained by positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) in the fasted state (> 6 hours) and in the glucose-loaded state (oral 50 g glucose load). In the both condition FDG-PET were performed in 18 cases with old myocardial infarction. PET images in the fasted state were divided into 2 groups (Group A; 12 cases and Group B; 6 cases). FDG uptake of normal region was visually absent (grade 0) in group A, whereas it was visually apparent (grade 1-3) in group B. Serum free fatty acid in group B was significantly lower than that in group A. In the 7 cases, the relation between myocardial FDG uptake of the infarcted regions and reversibility after coronary intervention was studied. Both in the fasted and in the glucose-loaded state, postoperative improvement was observed in the segments, in which myocardial uptake of FDG were visually apparent (glucose-loaded state, 11/13 segments; fasted state, 6/8 segments). Therefore FDG-PET images appeared to be useful for evaluating myocardial viability.

[Effect of DQ-2556, a new cephalosporin derivative, on fecal microflora]

A new cephalosporin derivative antibacterial agent, DQ-2556, was administered intravenously to 4 healthy adult male volunteers at 2 grams per dosage 2 times a day for 5 days, and degrees of effects of drug concentrations on the fecal microflora were investigated. 1. The total viable count remained unchanged during the study period due to the minimal change in the number of members of the family Bacteroidaceae, which were the most dominant organisms. In one of the volunteers, however, the total count was remarkably reduced immediately after the end of administration of the drug. 2. Among the obligate anaerobes, most of the organisms decreased except members of the family Bacteroidaceae. A marked increase of lecithinase-positive clostridia was noted in 2 volunteers. 3. The number of aerobes, including facultative anaerobes, members of the family Enterobacteriaceae were suppressed but bacilli and yeasts showed slight increases. In many cases, increases in enterococci were also observed. 4. DQ-2556 was not detected in the feces from any of the volunteers during the study period. 5. Neither Clostridium difficile nor its toxin D-1 was detected in any of the volunteers. 6. Diarrhoea or other side-effects were not noted in any of the volunteers.

Effect of nipradilol on cardiovascular hemodynamics during exercise in angina pectoris with old myocardial infarction

Nipradilol (3,4-dihydro-(2-hydroxy-3-isopropylamino)-propoxy-3-nitroxy-2H-1- benzopyran, K-351, CAS 81486-22-8) is a new type of beta-blocker with vasodilating action. The effect of nipradilol on hemodynamics at rest and during exercise with a multi-stage bicycle ergometer in supine position was studied in 8 male patients suffering from angina pectoris with old myocardial infarction. Nipradilol was orally given at the daily dose of 12 mg (b.i.d.) for one week, and various hemodynamic parameters were measured at rest and during exercise before and after the treatment with nipradilol. At rest, the blood pressure was almost unchanged, heart rate was significantly reduced, cardiac output tended to decrease, and the pulmonary blood pressure and left ventricular ejection fraction (EF) were almost unchanged. At peak exercise, the blood pressure tended to decline, heart rate was significantly reduced, cardiac output tended to decrease and the pulmonary blood pressure and EF increased significantly. Consequently, the antianginal effect of nipradilol is considered to be attributable to the reduction in myocardial oxygen consumption caused by a decrease in double product. It is thus suggested that nipradilol exerts its antianginal effect without adversely affecting the cardiac performance.

Chimeric HU-IHF proteins that alter DNA-binding ability

Chimeric proteins between Escherichia coli histone-like HU and IHF were constructed by genetic engineering, in which part of the arm region was replaced by the corresponding region of IHF alpha (designated as HupANhimA) or IHF beta (HupANhimD); alternatively, an alpha-helix 2-beta 1 region was replaced by the corresponding region of IHF alpha (HupAXhimA) or IHF beta (HupAXhimD) (symbols N and X indicate NotI and XhoI junctions). These proteins were synthesized in a hupA-hupB double-deletion mutant. HupANhimA exhibited marked reduction in nonspecific DNA binding in vitro, and a drastic loss of HU activity in replicative transposition of Mu phage in vivo. HupANhimD also showed a significant reduction in the ability for DNA binding, though this protein supported Mu phage development. In contrast, the other two chimeric HU proteins showed only slight changes in nonspecific DNA-binding ability: they retained activities for transposition of Mu phage in vivo. These observations confirm that the flexible arm of HU-2, a domain proposed for DNA binding [Tanaka et al., Nature 310 (1984) 376-381; Goshima et al., Gene 96 (1990) 141-145], plays an important role in the physiological function of this protein. The results indicate that a unique conformation of the arm structure of HU protein, particularly the N-terminal half of a two-strand antiparallel beta-ribbon of the structure, is important for the DNA-binding ability of this protein.

Unoperated thoracic aortic aneurysms: survival rates of the patients and determinants of prognosis

The purpose of this study was to evaluate the long-term prognosis of unoperated thoracic aortic aneurysms, and to detect the risk factors which determine the prognosis of unoperated patients. The subjects were 52 unoperated patients with 58 thoracic aortic aneurysms (22 of the ascending aorta, 36 of the descending aorta or the aortic arch) and 38 with abdominal aortic aneurysms. The survival rates of the patients with ascending aortic aneurysms at 3 years and 5 years and those of the patients with descending aortic aneurysms at 5 years were significantly higher than those of the patients with abdominal aortic aneurysms. The risk factors for rupture of thoracic aortic aneurysms were the large size of aneurysms and non-management by the cardiologist and the risk factors for death unrelated to the aneurysms were patient age, male gender and non-management by the cardiologist.

Reverse redistribution on Tl-201 SPECT images after reperfusion therapy for acute myocardial infarction: possible mechanism and prognostic implications

So-called reverse redistribution on stress Tl-201 imaging has been reported previously, but its significance and clinical implications are not well understood. In patients who received reperfusion therapy for acute myocardial infarction, we frequently observed reverse redistribution on stress Tl-201 images. To investigate the significance of reverse redistribution, 61 patients who underwent reperfusion within 4 h of the onset of chest pain underwent submaximal exercise Tl-201 imaging 3 weeks later. We performed simultaneous coronary arteriography and left ventriculography. We divided these 61 patients into three groups based on the pattern of Tl-201 images. Reverse redistribution was found in 19 patients (Group A), 12 patients had redistribution (Group B), and 30 patients had nonreversible defects (Group C). All patients in Group A had less residual stenosis than those in the other groups, and showed significant improvement of left ventricular function. Furthermore, 12 patients (Group A) demonstrated reverse redistribution or a normal pattern in a follow-up study performed 12 months later. However, in the delayed images the defect was smaller than that shown in the previous study. None of the patients had any symptoms and all returned to their previous occupations. In conclusion, reverse redistribution was common in patients undergoing reperfusion therapy for acute myocardial infarction, especially those with little residual stenosis. Reverse redistribution appears to indicate improved regional wall function in such patients.

[Pulmonary kinetics of 13N-ammonia in smoking subjects--a quantitative study using dynamic PET]

To evaluate the effect of smoking on nonrespiratory function in the lung, a dynamic PET with 13NH3 in the lung was performed in 18 normal volunteers without lung disease nor congestion (9 non-smokers, 4 exsmokers, 5 smokers). After intravenous bolus injection of 13NH3, twenty serial 5.5-second scans followed by six 30-second scans were performed. Regions of interests were assigned on the ventral, lateral and dorsal part of the right lung and time-activity curves were generated through 26 images. The activity curve demonstrated a biexponential clearance from the lung with fast and slow component. The retention fraction (RF), fractional size of the slow component, was calculated, and the half-times (t 1/2) of both components were also evaluated. A significant increase of RF and prolongation of t 1/2 of slow component were observed in smokers compared to non-smokers and exsmokers. However, no significant difference of RF nor t 1/2 of both components was observed between non-smokers and exsmokers. These results suggest that long term smoking may modify the pulmonary kinetics of 13NH3, but the change is reversible after cessation of smoking for one year or longer.

Expansion rate of thoracic aortic aneurysms and influencing factors

The risk of rupture of an aortic aneurysm increases with size and rapid expansion rate. We studied the expansion rate of thoracic aortic aneurysms and the factors influencing expansion rate, and compared the results with those of abdominal aortic aneurysms. Forty thoracic aortic aneurysms and 25 abdominal aortic aneurysms were serially examined with enhanced and nonenhanced computed tomography. The mean expansion rate of thoracic aortic aneurysms was 1.3 +/- 1.2 mm/yr and was significantly lower than 3.9 +/- 3.2 mm/yr of abdominal aortic aneurysms. The factors increasing expansion rate of thoracic aortic aneurysms were initial size of aneurysms, diastolic blood pressure, and presence of renal failure by univariate analysis. Multivariate analysis concerning the entire aortic aneurysms also revealed that the large size of the aneurysm and the presence of the aortic aneurysm in the abdomen increased expansion rate of aneurysms.

High-energy phosphate metabolism of the myocardium in normal subjects and patients with various cardiomyopathies--the study using ECG gated MR spectroscopy with a localization technique

Nuclear magnetic resonance spectroscopy (MRS) is a new technique for the evaluation of myocardial metabolism. Recently, localized MRS has been clinically available to measure by a non-invasive method the relative concentrations of the high-energy phosphate metabolites in the myocardium. We performed ECG gated P-31 MRS using ISIS (image-selected in vivo spectroscopy) in 15 normal volunteers, 12 patients with hypertrophic cardiomyopathy, 12 with left ventricular hypertrophy, 6 with dilated cardiomyopathy and 11 with specific heart muscle disease. Myocardial peak height ratios of PCr/gamma-ATP, Pi/gamma-ATP and PCr/Pi were measured. Myocardial P-31 MRS demonstrated a significant decrease in the ratio PCr/ATP in patients with hypertrophic cardiomyopathy and specific heart muscle disease as compared with normal subjects, indicating myocardial metabolic disturbance in these patients. The ratio of PCr/ATP in patients with dilated cardiomyopathy did not differ significantly from that of normal subjects. However, exercise MRS revealed a marked decrease of PCr peak in an asymptomatic patient with dilated cardiomyopathy, which may indicate a latent metabolic disturbance in the myocardium of dilated cardiomyopathy.

Prolongation of canine epidural anesthesia by liposome encapsulation of lidocaine

The purpose of our study was to produce a long-acting lidocaine by using a liposome that would entrap the drug. Egg yolk phosphatidylcholine and cholesterol were used as liposome materials. After epidural administration, the pharmacodynamics and pharmacokinetics of liposomal and free lidocaine were studied in 20 dogs. Two percent liposomal or free lidocaine (3.0 mL) was injected into the lumbar epidural space. Nerve blocking effects were estimated by measuring somatosensory evoked potentials. Recovery time from the epidural block in the liposomal lidocaine group (170 +/- 49.5 min) was approximately three times longer than that in the free lidocaine group (61 +/- 18.1 min). The areas under the drug concentration-time curves (AUC0-infinity) and time to maximal concentration (Tmax) in the liposomal lidocaine group were significantly larger than those in the free lidocaine group. These results suggest that the prolongation of epidural blockade by liposomal lidocaine is caused by a slow release of the drug from liposomes. The present study suggests that liposomal lidocaine can be used as a long-acting local anesthetic.

Segmental analgesic effect and reduction of halothane MAC from epidural fentanyl in humans

To clarify the site of action of epidural fentanyl, we compared the effects of epidural and intravenous fentanyl on the change in pressure pain threshold (PPT) and the minimum alveolar concentration (MAC) of halothane. Seventy patients who underwent gastrectomy in the PPT study group and 84 female patients who underwent hysterectomy in the MAC study group were assigned randomly to seven groups in each study. The seven groups each received a bolus injection of 1, 2, or 4 micrograms/kg of fentanyl, either intravenously or epidurally, and of saline solution epidurally. Compared with intravenous fentanyl, epidural fentanyl significantly increased (P less than 0.01) PPT around surgical incisions by approximately 50%, 100%, and 150% of preadministration levels 1 h after administration of 1, 2, and 4 micrograms/kg, respectively, and significantly reduced (P less than 0.05) halothane MAC at the same doses. These data suggest that the more potent analgesic and anesthetic effects of epidural fentanyl, compared with intravenous fentanyl, are due mainly to the segmental analgesia produced by its spinal analgesic action.