Modulation of morphine analgesia in alphaCGRP mutant mice

A homozygous CGRP-/- mouse line was generated by the targeted disruption of exon 5 in the calcitonin/alphaCGRP gene using homologous recombination. The mutant mice lack alphaCGRP mRNA. Furthermore CGRP immunoreactivity almost completely disappears from the spinal cord and is not at all observed in spinal ganglia and muscle synapses. However, motor end plates were still detected by acetylcholinesterase staining. Antinociceptive behavior tested by the tail flick and hot plate tests did not significantly differ in mutant and wild-type mice, except when challenged by morphine. Paradoxically, morphine analgesia was reduced in mutant mice compared with controls in the tail flick test, but not in the hot plate test. Thus, alphaCGRP differentially modulates opiate pain pathways.

Selection of cDNAs encoding putative type II membrane proteins on the cell surface from a human full-length cDNA bank

We have developed a simple method to test whether a hydrophobic segment near the N-terminus of a protein functions as a type II signal anchor (SA) in which the N-terminus faces the cytoplasm. A cDNA fragment containing the putative SA sequence of a target clone was fused in-frame to the 5' end of a cDNA fragment encoding the protease domain of urokinase-type plasminogen activator (u-PA). The resulting fused gene was expressed in COS7 cells. Fibrinolytic activity on the cell surface was measured by placing a fibrin sheet in contact with the transfected COS7 cells after removing the medium. When the cDNA fragment encoded a SA, the fibrin sheet was lysed by the u-PA expressed on the cell surface. The fibrinolytic activity was not detected in the culture medium, suggesting that the u-PA remains on the cell surface anchored via the SA in the membrane without being cleaved by signal peptidase. This fibrin sheet method was successfully applied to select five novel cDNA clones encoding putative type II membrane proteins from a human full-length cDNA bank.

Hypoproteinemia caused by tricuspid regurgitation: report of a case

A case of tricuspid regurgitation (TR) complicated by severe hypoproteinemia is presented herein. A 68-year-old man who had undergone coronary artery bypass grafting (CABG) for postinfarction angina suffered repeated inferior myocardial infarction due to obstruction of the proximal right coronary artery, 3 years after which he developed systemic edema. Investigations revealed TR associated with hypoproteinemia; however, treatment consisting of aggressive diuretic therapy and albumin administration proved ineffective. The hypoproteinemia manifested as protein-losing enteropathy clinically, and the tricuspid valve was replaced to eliminate high venous pressure. The serum protein levels became normalized after the operation. Although TR is generally well tolerated in the absence of pulmonary hypertension, surgical management is recommended for patients with severe protein deficiency resistant to medical treatment.

The implication of anthracosis in the development of pulmonary adenocarcinoma

The relationship between anthracosis, which is the deposition of black dust matter in the lung parenchyma, and the development of pulmonary adenocarcinoma has not been fully characterized. In order to clarify whether background black dust matter deposition could be implicated in the development of pulmonary adenocarcinoma, we measured the level of anthracosis at autopsy in 47 patients who had died of pulmonary adenocarcinoma. Both lungs of all 47 cadavers were examined. Twenty-micrometer sections were cut from formalin-fixed, paraffin-embedded blocks of the largest cut surface of each lung. Black dust matter was extracted from the sections and blotted onto a nitrocellulose membrane. The density of the blotted black dust matter was then analyzed using an imaging densitometer. There were no significant differences in the density of black dust matter deposition between lungs affected by pulmonary adenocarcinoma and control lungs. However, well differentiated adenocarcinomas tended to develop more frequently than poorly differentiated ones in lungs showing less deposition. We found a very strong correlation between the degree of black dust matter deposition and smoking history. Patients with severe anthracosis tended to have a poorer prognosis than those with mild anthracosis.

Microsatellite instability and frameshift mutations in the Bax gene in hereditary nonpolyposis colorectal carcinoma

We studied microsatellite instability (MI) and bax gene abnormalities in colorectal carcinomas from 36 patients diagnosed as having hereditary nonpolyposis colorectal cancers (HNPCC) according to the clinical criteria (12 with confirmed HNPCC in group A and 24 at high risk of HNPCC in group B) and from 20 randomly selected patients with other colorectal cancers. MI was examined at 4 dinucleotide microsatellite loci and one mononucleotide locus. Frameshift mutations in the bax gene were detected by polymerase chain reaction-single strand conformation polymorphism analysis. MI was detected in 7 of the 12 patients in group A and 12 of the 24 in group B. Three MI patterns were identified: type 1, MI in both mono- and dinucleotide repeats; type 2, MI only in mononucleotide repeats and type 3, MI only in dinucleotide repeats. Most MI-positive patients in group A showed type 1 MI, whereas in group B, 5 showed type 1, 3 showed type 2 and 4 showed type 3. Frameshift mutations in the bax gene correlated strongly with type 1 and type 2 MI. These results indicate that mutations of different DNA mismatch repair genes may cause several types of MI and result in several different clinical phenotypes of HNPCC. The bax gene may be one of the target genes which play a role in the tumorigenesis of HNPCC.

Esophageal dysplasia and chronic esophagitis: detection at upper gastrointestinal tract endoscopy

Cancer of the esophagus becomes symptomatic at an advanced phase with a late diagnosis, when the tumor is already incurable. Early diagnosis has been shown to improve the survival rates. Conventional esophagoscopy is largely available but its sensitivity to detect early cancer or precancerous lesions remains controversial. In this study we tested the sensitivity of conventional esophagoscopy to identify suspicious areas and compared to histopathology of endoscopic biopsies to detect dysplasia and chronic esophagitis in a population at risk for cancer in southern Brazil. Adult males scheduled to have outpatient endoscopy were examined by two experienced endoscopists and any small (< 5 mm) plaque, nodule, erosion, hyperemia and or friable areas of the mucosa were biopsied and looked for the presence of early cancer or precancerous lesions. Normal appearing mucosa at the middle third of the esophagus was also biopsied and results compared for sensitivity, specificity, positive and negative predictive value. Of the 89 individuals with satisfactory biopsies, 3 had dysplasias, 29 moderate or severe chronic esophagitis and 57 normal findings at the histopathological study. We found no early cancer. We found two large, vegetating lesions confirmed to be advanced squamous cell carcinoma but they were excluded from analysis. To detect dysplasia or moderate/severe chronic esophagitis conventional esophagoscopy had a sensitivity of 40.6%, specificity of 78.9%, positive predictive value of 52% and negative predictive value of 70.3.

CONCLUSIONS

In this study, conventional esophagoscopy had a low sensitivity to detect dysplasias and/or chronic esophagitis and techniques to improve endoscopic identification of these lesions in individuals at risk for cancer are much needed.

Supraannular aortic root enlargement in patients with small aortic annulus: efficacy and safety

BACKGROUND

To accommodate optimal sized aortic valve, our experiences with supraan-nular aortic root enlargement (SAE) in 20 patients with small aortic annulus have been described.

METHODS

From June 1981 to April 1996, aortic valve replacement with a St. Jude Medical (SJM) valve had been performed in 46 patients with aortic stenosis consecutively. After August 1993, we employed SAE in patients to insert 23 mm or larger aortic prostheses (SAE group, n = 20; control group, n = 26). Patients were followed-up for a period of 1.7 to 8.3 years.

RESULTS

There were no intra- or postoperative complications. The pressure gradient across the prosthesis was greater than 30 mmHg in 4 patients of the control group and in 1 patient of the SAE group. Only in nineteen patients (73%) of the control group, 23 mm or larger sized valves could be implanted by a conventional technique. By contrast, with SAE, 23 mm or larger sized SJM prostheses were possible to implant in 19 out of 20 patients (95%).

CONCLUSION

To avoid valve-patient mismatch, SAE of aortic root is safe and effective.

[A case of infective thoracic aortic aneurysm ruptured to the lung]

We report a successful surgical treatment of an infective thoracic aortic aneurysm ruptured to the left lung. A 63-year-old man who had been suffering from fever and cough showed twice of hemoptysis. Chest CT revealed a descending thoracic aortic aneurysm ruptured to the left lung. A semiemergent operation was performed. At operation, aneurysm of descending thoracic aorta was found adherent to the left lung. Aneurysmectomy with left pneumonectomy was carried out. The postoperative course of the patient was uneventful. Conceivably, in order to avoid massive intraoperative bleeding during division of dense adhesion and postoperative graft infection, concomitant lung resection is necessary.

Isolation and characterization of a cDNA for human mouse, and rat full-length stem cell growth factor, a new member of C-type lectin superfamily

cDNA encoding stem cell growth factor (SCGF; 245 aa), a novel human growth factor for primitive hematopoietic progenitor cells, has been previously reported (Hiraoka, A., Sugimura, A., Seki, T., Nagasawa, T., Ohta, N., Shimonishi, M., Hagiya, M. and Shimizu, S. Proc. Natl. Acad. Sci. USA 94, 7577-7582, 1997). Here we report the cloning and characterization of a full-length SCGF cDNA. This protein consists of 323, 328 and 328 aa in the human, murine and rat forms, the latter two of which share 85.1% and 83.3% aa identity, and 90.4% and 90.4% aa similarity to the human protein, respectively. Because the newly identified human clone encodes the protein longer by 78 aa than that previously identified, we term the longer clone as hSCGF-alpha and the shorter one as hSCGF-beta. The computer-assisted homology search reveals that SCGF is a new member of the C-type lectin superfamily, and that SCGF shows the greatest homology to tetranectin among the members of the family (27.2-33.7% aa identity and 46.0-53.6% aa similarity). SCGF transcripts are detected in spleen, thymus, appendix, bone marrow and fetal liver. Fluorescent in situ hybridization mapping indicates that the SCGF gene is located on chromosome 19 at position q13.3 for human form and on chromosome 7 at position B3-B5 for murine form, which are close to flk-2/flt3 ligand and interleukin-11 genes of both human and murine species.

Experimental study on the scavenging effects of ginsenosides on oxygen free radicals using model of heterotopic heart transplantation in rats

Oxygen-derived free radicals play an important role in myocardial injury associated ischemia and reperfusion. To investigate whether ginsenosides, as an additive agent of cardioplegic solution, can decrease toxicity of oxygen free radicals in myocardial injury, a heterotopic heart transplantation model in Wistar rats was employed. St. Thomas II cold cardioplegia containing ginsenosides 80 mg/l was used in the experimental group. St. Thomas II cold cardioplegia alone was used in the control group. After global ischemia for 60 minutes and reperfusion for 30 minutes of a transplanted heart, SOD activity in the myocardium treated with ginsenosides was significantly higher than that in the control group (N=10, p< 0.01), whereas the MDA in the myocardium treated with ginsenosides were markedly lower than that of the control group (p< 0.01). The amounts of oxygen free radicals in the myocardium treated with ginsenosides were significantly lower than that of the control group (p <0.001). This study demonstrates that ginsenosides, as a proper additive agent of cardioplegic solution, can decrease toxicity of oxygen free radicals, suggesting one of the mechanisms for its protective effects against myocardial ischemia and reperfusion injury.

Cloning of human polyubiquitin cDNAs and a ubiquitin-binding assay involving its in vitro translation product

During large-scale in vitro translation analysis of a human full-length cDNA bank, we found a clone producing a remarkably smaller translation product than that expected from the open reading frame. The cDNA encodes a polyubiquitin, UbC, composed of nine tandem repeats of the ubiquitin unit. The bank contained twelve UbC cDNAs including four full-length ones. Sequencing analysis of these clones showed that UbC cDNAs can be classified into two types, UbC1 and UbC2, in each of which there are six polymorphic nucleotide variations. The present UbC cDNA was in vitro translated in a rabbit reticulocyte or wheat germ extract to produce a free ubiquitin labeled with [35S]methionine. The labeled ubiquitin could be used as a substrate for thiol ester formation with ubiquitin-activating enzyme E1 or ubiquitin-conjugating enzyme E2.

[Long-term results of patients undergone surgical repair for acute type A dissection]

We evaluated the long-term results of 28 operative survivors who underwent surgical repair for acute type A dissection. Residual dissection of the thoracic aorta was found in 21 patients (75.0%) postoperatively, and 6 of them underwent reoperation with no operative death. There were 2 late death; one died in the third operation for thoracoabdominal aorta and the other died of cancer. Two of 4 patients with Marfan's syndrome required total aortic replacement ultimately. Since the elective reoperation can be performed safely, careful follow-up and management is essential for the improved survival of the patients with residual aortic dissection.

Long-term thrombosis after transvenous permanent pacemaker implantation

To assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis after long-term transvenous permanent pacemaker implantation, venograms were performed in 100 consecutive patients at the elective replacement of the pacemaker. Mean follow-up period after initial transvenous permanent pacemaker implantation was 6.0 years. The venograms demonstrated normal in 77 patients. The remaining 23 venograms showed venous stenosis in 11 patients and total obstruction in 12 patients. Twenty-one of these 23 patients had venous collateral circulation. No difference was found in the incidence of venous abnormalities according to the route of entry, the lead insulation, the total number of the implanted leads, and anticoagulant and antiaggregant drugs. All these patients have remained asymptomatic. In conclusion, the incidence of venous thrombosis after long-term transvenous pacing is 23% and the causes of venous thrombosis may be endothelial trauma and underlying venous stenosis. As this article describes a retrospective limited study, we cannot find the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs to prevent venous thrombosis formation after transvenous permanent pacemaker implantation. Further prospective study will be needed to assess the efficacy of prophylactic administration of anticoagulant and antiaggregant drugs.

Surgical treatment of the coronary artery to pulmonary artery fistulas in adults

Coronary artery to pulmonary artery fistula (CA-PAF) is a rare congenital anomaly. The purpose of this retrospective study was to analyze 11 adult patients with CA-PAFs treated surgically, and to evaluate the surgical management and long-term results. There were no surgical deaths and all patients survived the follow-up periods (mean 7.2 years). All symptomatic patients improved their New York Heart Association functional class. As surgical correction is safe and effective, with good long-term results, all the patients with CA-PAF in adults can be candidates for surgery to prevent life-threatening complications.

Transiliac vein approach to a permanent pacemaker implantation after aortic valve reoperation

This article describes the case of a 71-year-old woman in whom a permanent pacemaker implantation was performed through an iliac vein because of superior vena cava obstruction after aortic valve reoperation. During a 6-month follow-up, the patient did well and the pacemaker performance was satisfactory.

Identification and characterization of a novel SH3-domain binding protein, Sab, which preferentially associates with Bruton's tyrosine kinase (BtK)

Protein interaction cloning method was used to identify a novel molecule, Sab, which binds to the SH3 domain of Bruton's tyrosine kinase (Btk), the deficient cytoplasmic tyrosine kinase in human X-linked agammaglobulinemia and murine X-linked immunodeficiency. Immunoprecipitation using the anti-Sab antibody identified the protein product of the gene as a 70 kDa molecule. While Sab does not have a proline-rich sequence, it was shown to bind to Btk through the commonly conserved structure among SH3 domains. Remarkably, Sab exhibited a high preference for binding to Btk rather than to other cytoplasmic tyrosine kinases, which suggests a unique role of Sab in the Btk signal transduction pathway.

Structure of the mouse klotho gene and its two transcripts encoding membrane and secreted protein

We previously established a novel mouse model for human aging and identified the genetic foundation responsible for it. A defect in expression of a novel gene, termed klotho (kl), leads to a syndrome resembling human aging in mice. The kl gene encodes a single-pass membrane protein whose extracellular domain carries homology to beta-glucosidases. In this report, we present the entire mouse kl gene organization. The mouse kl gene spans about 50 kilobases and consists of five exons. The promoter region lacks a TATA-box and contains four potential binding sites for SP1. We further show that two kl gene transcripts encoding membrane or secreted protein are generated through alternative transcriptional termination. These findings provide fundamental information for further study of the kl gene which may regulate aging in vivo.

Halofuginone inhibits neointimal formation of cultured rat aorta in a concentration-dependent fashion in vitro

Halofuginone, an anticoccidial quinoazolinone, can specifically inhibit collagen type alpha1 (I) synthesis and gene expression, and also inhibits cultured smooth muscle cell proliferation. The aim of this study was to investigate the effect of halofuginone on neointimal formation of rat aorta after culture in a concentration-dependent manner in vitro. Thoracic aorta of Wistar rats was removed and manipulated to damage the endothelium under sterile conditions, and culture for 15 days in halofuginone-free or halofuginone-added culture medium (n = 20). Segments of cultured aorta were studied by histologic and immunohistochemical methods. Proliferation of neointimal layers consisting of loose multilayer cellular structure was observed in the halofuginone-free control group after 15 days of rat aorta culture, and neointimal formation was significantly decreased as an increasing concentration of halofuginone was added. As with precultured fresh aorta, no intimal proliferation was observed in the cultured segments of aorta with 500 ng/ml halofuginone added to culture medium. The proliferation of cell nuclear antigen index was significantly higher in the halofuginone-free control group than that in the halofuginone-added groups. The present results suggest that halofuginone can inhibit neointimal formation of rat aorta after culture in a concentration-dependent fashion in vitro.

Expression cloning of cDNA encoding a human beta-1,3-N-acetylglucosaminyltransferase that is essential for poly-N-acetyllactosamine synthesis

The structure and biosynthesis of poly-N-acetyllactosamine display a dramatic change during development and oncogenesis. Poly-N-acetyllactosamines are also modified by various carbohydrate residues, forming functional oligosaccharides such as sialyl Lex. Herein we describe the isolation and functional expression of a cDNA encoding beta-1,3-N-acetylglucosaminyltransferase (iGnT), an enzyme that is essential for the formation of poly-N-acetyllactosamine. For this expression cloning, Burkitt lymphoma Namalwa KJM-1 cells were transfected with cDNA libraries derived from human melanoma and colon carcinoma cells. Transfected Namalwa cells overexpressing the i antigen were continuously selected by fluorescence-activated cell sorting because introduced plasmids containing Epstein-Barr virus replication origin can be continuously amplified as episomes. Sibling selection of plasmids recovered after the third consecutive sorting resulted in a cDNA clone that directs the increased expression of i antigen on the cell surface. The deduced amino acid sequence indicates that this protein has a type II membrane protein topology found in almost all mammalian glycosyltransferases cloned to date. iGnT, however, differs in having the longest transmembrane domain among glycosyltransferases cloned so far. The iGnT transcript is highly expressed in fetal brain and kidney and adult brain but expressed ubiquitously in various adult tissues. The expression of the presumed catalytic domain as a fusion protein with the IgG binding domain of protein A enabled us to demonstrate that the cDNA encodes iGnT, the enzyme responsible for the formation of GlcNAcbeta1 --> 3Galbeta1 --> 4GlcNAc --> R structure and poly-N-acetyllactosamine extension.

Human cDNA encoding a novel TGF-beta superfamily protein highly expressed in placenta

Recently, we developed a simple method for detecting a secretory signal sequence encoded by a cDNA fragment. In this study, we used this method to select cDNA clones encoding secretory proteins from a human full-length cDNA library. Full-sequencing analysis of the candidate clones revealed that one clone encoded a novel TGF-beta superfamily protein. The clone encodes a protein of 308 amino acids of which the C-terminal region shows a characteristic feature of TGF-beta superfamily proteins: seven conserved cysteine residues at the C-terminal preceded by a putative processing site composed of a basic amino acid repeat. The corresponding transcripts are highly expressed in the placenta, so the novel protein may play an important role in reproduction.

Is the dog a useful model for accelerated calcification study of cardiovascular bioprostheses?

Chitosan posttreatment has been shown to be effective in prevention of calcification of the glutaraldehyde treated bovine pericardium when implanted subdermally in rats for 12 weeks. The efficacy of chitosan posttreatment in complete calcium mitigation of the glutaraldehyde treated porcine aortic valves implanted in the right side of the heart in dogs was well-documented in our previous study. In this study, an attempt has been made to evaluate the merit of the chitosan posttreatment in prevention of calcification of the glutaraldehyde (GA) treated porcine aortic valved conduits in the systemic circulation in dogs for a period of 5 months. Eleven mongrel dogs underwent left thoracotomy. Porcine aortic valved conduits treated with 0.625% GA (n = 5) and GA-chitosan (n = 6) were implanted in the descending thoracic aortas of the dogs for 5 months. Gross histological observations showed no calcification in either the 0.625% GA treated or in the GA-chitosan treated valved conduits at 5 months. This was confirmed by results of quantitative analyses for calcium in each explant. There was no significant difference in calcium content between the GA only (Ca, 0.43 +/- 0.26 mg/g) and GA-chitosan treated (Ca, 0.51 +/- 0.19 mg/g; p = 0.5959) valved conduits. This study suggests that the dog is not a suitable model for evaluating the efficacy of a calcium mitigating agent in bioprostheses implanted in systemic circulation.

Minimum inhibitory concentration of various single agents and the effect of their combinations against Helicobacter pylori, as estimated by a fast and simple in vitro assay method

OBJECTIVES

Fast and simple in vitro methods of accurately assaying anti-Helicobacter pylori (H. pylori) activity are needed to facilitate the selection of optimal drugs for the eradication of H. pylori. With that purpose in mind, we developed a broth microdilution technique that uses a 96-well flat-bottom microplate.

METHODS

Clinical isolates of H. pylori were placed in 25-cm2 tissue culture flasks and were grown in an atmosphere of 5% CO2 in air at 37 degrees C and 100% humidity. Then they were inoculated in 96-well flat-bottom microplates. After 24 h, the bacterial growth was assessed by automatic measurement at A450 with a microplate reader. Minimum inhibitory concentrations (MICs) of 11 drugs against H. pylori and the effect of two-drug combinations were respectively evaluated by the broth microdilution technique and by calculating the fractional inhibitory concentration index according to the checkerboard titration method.

RESULTS

The MICs of all drugs tested with this system roughly agreed with those of previous reports in which the agar dilution method was used. The MIC of lansoprazole, a proton pump inhibitor, was low (0.88 microg/ml) and surpassed that of metronidazole (3.15 microg/ml). The effect of the combination of macrolide antibiotics with tetracycline was favorable. The proton pump inhibitor demonstrated a strong additive effect with macrolide antibiotics and fostered the activity of ecabet sodium (mucosal protective agent).

CONCLUSION

This system could estimate the MIC of individual drugs quickly and simply, and could accurately measure the efficacy of two-drug combinations in vitro.

Eradication of Helicobacter pylori in patients with end-stage renal disease under dialysis treatment

The efficacy and safety of combination therapy with amoxicillin, lansoprazole, and plaunotol for the eradication of Helicobacter pylori in patients on dialysis were evaluated. The study subjects comprised 15 dialysis patients in whom H pylori had been found in the gastric mucosa. The patients were given 500 mg amoxicillin once a day for 3 weeks, 30 mg lansoprazole once a day for 8 weeks, and 80 mg plaunotol three times a day for 24 weeks. Endoscopy was performed on entry and at 4 and 24 weeks after cessation of amoxicillin. The concentrations of serum gastrin and gastric juice ammonia also were measured. Fourteen patients completed the treatment protocol, one having dropped out because of nausea and diarrhea. H pylori was eradicated in 11 of the 14 patients 4 weeks after the end of amoxicillin therapy (eradication rate, 78.6%). All but one patient was free of H pylori 24 weeks after the amoxicillin was discontinued. Patients who became negative for H pylori had significantly decreased serum gastrin and gastric juice ammonia concentrations. Our findings indicate that a combination of amoxicillin, lansoprazole, and plaunotol can be used to eradicate H pylori in patients on dialysis.

Mitral regurgitation caused by mitral paraannular cyst

A case of mitral regurgitation (MR) caused by mitral paraannular cyst is reported. A 37-year-old woman on maintenance hemodialysis was admitted to Akita University Hospital because of congestive heart failure. Echocardiography revealed mitral paraannular cyst, which caused coaptation failure of the mitral leaflets and significant MR. She underwent decapsulation of the cyst followed by mitral valve replacement. Postoperative echocardiography showed no recurrence of the cyst three years after surgery. Although mitral annular calcification has been described as a cause of MR in patients with uremia, a report of a solitary intracardiac cyst which causes significant MR is quite rare.

Surgical treatment of isolated secundum atrial septal defect in patients more than 50 years old

BACKGROUND

Arrhythmia-related thromboembolic accidents continue to occur in patients even after closure of secundum atrial septal defect. Older age is usually not a contraindication to the repair of an atrial septal defect. To assess the importance of the type of management in elderly patients with atrial septal defect our clinical experience is reviewed.

METHODS

Between 1974 and 1994, 49 patients 50 years of age or older (average, 57.4 years) underwent surgical closure of secundum atrial septal defect. All patients have been followed up for 2 to 21 years (mean, 9.7 years).

RESULTS

There were no operative deaths. Functional classes in most of the patients were improved after operation. There were two cerebrovascular thromboembolic accidents with one permanent neurologic dysfunction, hemiparesis, and one septal dehiscence in the early postoperative period. One patient (2%) died of renal failure 6 years after operation, late arrhythmias developed in 3 patients (6%), 3 patients had a late stroke (6%), and 1 patient was not available for follow-up.

CONCLUSIONS

Long-term operative results are satisfactory and beneficial to the quality of life in elderly patients. Because there is no safe and effective nonsurgical alternative to surgical closure, atrial septal defect repair in elderly patients without severe pulmonary vascular disease should not be delayed once the diagnosis had been made.

Composite graft replacement of the aortic root in patients with Marfan's syndrome

Between October, 1979 and September 1994, 18 consecutive patients with Marfan's syndrome underwent replacement of the ascending aorta and aortic valve with a composite graft. There were 11 men and seven women; the mean age was 38.7 years. All patients had annuloaortic ectasia with significant aortic regurgitation. Ten of the 18 patients had aortic dissection. Concomitant procedures were performed in three patients. The hospital mortality rate was 17%, and two patients with concomitant procedures died early after surgery. There were three late deaths, two of which were related to late aortic complications. The actuarial 8-year survival rates in patients with and without aortic dissection were 58.3% and 77.8%, respectively. Since aortic dilatation and its complications are progressive in patients with Marfan's syndrome, improved surgical results can be obtained early in the course of the disease before cardiac disturbances and aortic dissections emerge.

Cloning and expression of cDNA encoding a human ubiquitin-conjugating enzyme similar to the Drosophila bendless gene product

cDNA encoding a novel human ubiquitin-conjugating enzyme has been cloned from an epidermoid carcinoma KB cDNA library. This clone encodes a protein of 152 amino acids with a calculated M(r) of 17,137. The amino acid sequence showed 80% identity with the Drosophila's bendless gene product (ubiquitin-conjugating enzyme E2). The corresponding transcripts are highly expressed in heart, skeletal muscle, and testis. The product expressed in Escherichia coli exhibited the ability to form a thiol ester linkage with ubiquitin in a ubiquitin-activating enzyme E1-dependent manner. These results suggest that the obtained cDNA encodes a novel human E2 which may be involved in protein degradation mainly in the muscles and testis.

[Aortic root replacement employing Cabrol and Piehler techniques]

Between February, 1982, and September, 1994, 24 patients underwent aortic root replacement using a valve-bearing composite graft and coronary perfusion grafts. The indications for surgery were annulo-aortic ectasia in 21 patients, and aortic dissection associated with significant aortic regurgitation in 3 patients. Aortic root was reconstructed employing the techniques described by Cabrol and colleagues (Cabrol operation) in 16, and by Piehler and Pluth (Piehler operation) in 8. Two of 16 patients who underwent Cabrol operation required concomitant procedures. Four patients (25.0%) who underwent Cabrol operation had technical troubles relating to coronary reattachements (kinking and torsion of coronary grafts in 2, obstruction of left limb of coronary graft in 1, and coronary graft compression by aortic wall wrapping in 1), while one patient (12.5%) having Piehler operation had coronary graft compression by partial wrapping of aortic root. The hospital deaths occurred in 4 patients undergone Cabrol operation, with the hospital mortality rate being 16.7%. Three patients including 2 with concomitant procedures died of low cardiac output and one died of rupture of residual dissecting aneurysm of the aortic arch. No pseudoaneurysm nor anastomotic stenosis was observed in any hospital survivors. Late deaths occurred in 5 patients, in whom there was no late complication relating to coronary reconstruction. However, late obstruction of left ostial stenosis developed in one patient who underwent Piehler operation, which required coronary artery bypass. We conclude that aortic root replacement using coronary perfusion grafts provides sound coronary anastomoses without late pseudoanurysm. Coronary reattachments is facilitated by use of Piehler technique, preventing coronary graft kinking or torsion. Late coronary ostial stenosis should be considered as a possible cause of fatal myocardial infarction and sudden death, and careful follow-up is required for patients having these kinds of operation for the prevention of late cardiac events.

Major identity determinants in the "augmented D helix" of tRNA(Glu) from Escherichia coli

By a kinetic analysis of 59 variant transcripts of Escherichia coli tRNA(Glu) with glutamyl-tRNA synthetase (GluRS), the U11.A24 base-pair, the U13.G22..A46 base-triple, and the lack of residue 47 (delta47) were found to serve as major determinants for tRNA(Glu) identity. This is the first system for which major identity determinants are reported to be clustered in the "augmented D helix", consisting of the D stem with some neighboring residues and the variable loop. Other identity determinants are U34, U35, C36 and A37 in the anticodon loop, and G1.C72 and U2.A71 in the acceptor stem. Phosphate-group protection by GluRS from ethylnitrosourea was observed most strongly for the minor groove side of D-stem helix, indicating that GluRs tightly binds to the D stem for recognition, on the minor groove side, of the potent identity-determinant groups of the U11.A24 and U13.G22 base-pairs. A46 is not involved in direct recognition by GluRS; the U13.G22..A46 base-triple is required probably for formation of the structural features that are recognized by GluRS. In this context, the essential role of characteristic delta47 in tRNA(Glu) identity may be to maintain the U13.G22..A46 base-triple.

[Coronary artery bypass grafting in a patient with severe coronary disease due to Kawasaki disease: a case report]

A 14-year-old girl with severe coronary artery disease due to mucocutaneous lymph node syndrome, "Kawasaki disease", admitted to our hospital. Though she had no angina on any effort in her daily life, coronary angiography (CAG) demonstrated 90% stenosis and a large aneurysm of left main trunk. Based on the CAG findings, we determined to do the coronary artery bypass grafting (CABG) to left anterior descending artery (LAD) and 1st diagonal branch (D1) to prevent the occurrance of fatal acute myocardial infarction. We attempted to use bilateral internal thoracic arteries (ITAs) at the beginning of this surgery. While LAD was grafted with left one, D1 was done with saphenous vein (SV) because of difficulty of harvesting right one. The weaning from cardiopulmonary bypass was easy and the postoperative course was of no event. A month later, CAG showed the good patency of both left ITA and SV graft.

A three-dimensional structure model of the complex of glutamyl-tRNA synthetase and its cognate tRNA

A docking model of glutamyl-tRNA synthetase (GluRS) and tRNAGlu was constructed, on the basis of the distinguished similarity between the X-ray crystallographic three-dimensional structures of the N-terminal halves of the Thermus thermophilus GluRS in the free state and the Escherichia coli glutaminyl-tRNA synthetase in a complex with tRNAGln. The modeled structure is energetically favorable and is also well consistent with the results of site-directed mutagenesis studies. The model indicates that the GluRS-specific insertions 2 and 3 fit and bind to the acceptor stem and the D arm, respectively, of the cognate tRNA without affecting other contacts. In particular, insertion 3 strongly interacts with the two D-stem base pairs that are essential for the tRNA-GluRS recognition.

Preliminary evidence suggesting variations of GtH 1 and GtH2 mRNA levels at different stages of gonadal development in rainbow trout, Oncorhynchus mykiss

To study the variations of alpha and beta GtH 1 and 2 gene expression during gonadal development in male and female rainbow trout, chum salmon alpha and beta GtH 1 and 2 probes were used. The alpha subunit cDNA probe used is identical to the cDNA encoding the alpha subunit common to both GtH 1 and 2. Total RNAs were prepared from pooled pituitaries and the validation of the use of these probes for studying the variation of GtH mRNAs was made by Northern blot analysis. The quantitative determination of GtH mRNAs employed slot blot hybridization. In males and females, beta GtH 1 predominates in early stages of gonadal development (spermatogonia A and previtellogenesis), beta GtH 2 being weakly expressed. Both beta GtH 1 and beta GtH 2 are expressed during prespermiation, spermiation, and the periovulatory period with a predominance of beta GtH 2. In both sexes alpha GtH variations follow beta GtH 2 variations.

Dacron coronary graft obstruction after composite graft replacement of aortic root

Obstruction of the left coronary ostial anastomosis is a rare late complication after composite graft replacement of the ascending aorta and the aortic valve with separate Dacron coronary grafts. Intimal proliferation caused by the turbulent blood flow at this site may be the cause of the obstruction, which is considered a possible cause of late cardiac events such as sudden death and global myocardial infarction. We describe a case of tight stenosis at the left coronary ostial anastomosis in a 38-year-old woman with Marfan's syndrome who had undergone a composite graft replacement that employed separate Dacron coronary grafts.

[Squamous cell carcinoma of the ureter as a late complication of ureterocutaneostomy--a case report]

A case of squamous cell carcinoma of the ureter was reported. A 62-year-old woman, who underwent left nephrectomy and right ureterocutaneostomy at the age of thirty-one because of tuberculosis of the urinary tract, visits our hospital periodically for an ureteral catheter change. An urgent nephrostomy was performed because of ureteral stricture on March 8, 1994. Three months later tenderness and induration appeared at the former ureteral stoma. The resected specimen was histologically diagnosed as squamous cell carcinoma. Right palliative ureterectomy did not produce the desired effects due to the invasion of the tumor into the surrounding organs. In this rare case, it is suggested that chronic infection and irritation of the indwelling catheter might be causative of squamous cell carcinoma of the ureter.

Architectures of class-defining and specific domains of glutamyl-tRNA synthetase

The crystal structure of a class I aminoacyl-transfer RNA synthetase, glutamyl-tRNA synthetase (GluRS) from Thermus thermophilus, was solved and refined at 2.5 A resolution. The amino-terminal half of GluRS shows a geometrical similarity with that of Escherichia coli glutaminyl-tRNA synthetase (GlnRS) of the same subclass in class I, comprising the class I-specific Rossmann fold domain and the intervening subclass-specific alpha/beta domain. These domains were found to have two GluRS-specific, secondary-structure insertions, which then participated in the specific recognition of the D and acceptor stems of tRNA(Glu) as indicated by mutagenesis analyses based on the docking properties of GluRS and tRNA. In striking contrast to the beta-barrel structure of the GlnRS carboxyl-terminal half, the GluRS carboxyl-terminal half displayed an all-alpha-helix architecture, an alpha-helix cage, and mutagenesis analyses indicated that it had a role in the anticodon recognition.

[Evaluation on the perioperative left ventricular function of aortic valve replacement in patients with chronic aortic regurgitation]

To evaluate the perioperative left ventricular function in 36 patients undergoing aortic valve replacement (AVR) in patients with isolated chronic aortic regurgitation (AR), hemodynamic variables before and within the first 24 hours and one month after operation were measured with Swan-Ganz catheter and echocardiography. The patients were divided into two groups based on preoperative left ventricular end-systolic volume index (LVESVI): 5 patients had a LVESVI of 90 ml/m2 and greater (group I), 31 had a LVESVI smaller than 90 ml/m2 (group II). Left ventricular dimension at end-diastole and end-systole, left ventricular end-diastolic volume index at one month after operation significantly decreased in comparison with that of preoperation. However, left ventricular ejection fraction in the two groups were not improved, and left ventricular mass index in group I did not decreased. On the other hand, changes of cardiac index, stroke volume index and left ventricular stroke work index within the first 24 hours after operation were not significantly different between the two groups. The incidence of postoperative premature ventricular contraction in group I was significantly higher than that of group II. However, there was no difficult problems in postoperative management of the two groups. It is suggested that AVR in AR with left ventricular dysfunction can safely be operated and its postoperative management is similar to AVR in AR with no left ventricular dysfunction.

cDNA cloning and characterization of human glyoxalase I isoforms from HT-1080 cells

We have isolated two kinds of cDNA clones encoding glyoxalase I from a human fibrosarcoma HT-1080 cDNA library. One of them is identical to the glyoxalase I cDNA isolated by us, and the other encodes a protein in which alanine at position 111 of the reported sequence for glyoxalase I is replaced by glutamic acid. When the two cDNAs were co-translated in vitro, three bands representing two homodimers and one heterodimer appeared on native polyacrylamide gel electrophoresis, as observed for glyoxalase I purified from human erythrocytes or derived from a HT-1080 cell lysate. Escherichia coli cells carrying an expression vector of one of the novel glyoxalase I cDNAs showed glyoxalase I activity. These results reveal that two isoforms of human glyoxalase I showing different electrophoretic properties result from a change in one amino acid residue.

Novel homogeneous enzyme immunoassay: chitinase activity enhancement immunoassay (CAEIA)

A novel homogeneous enzyme immunoassay has been developed that takes advantage of the observation that the activity of a bacterial chitinase could be enhanced by the binding of a ligand conjugate of a monoclonal antibody to the enzyme (L-MAbchi). The enhancement was suppressed by an antiligand antibody (AbL). Free ligand molecules competed for AbL combining with L-MAbchi, and the suppression of the enhancement was reduced. Thus the concentration of free ligand could be estimated. Biotin was used as a ligand in this model experiment. When this monoclonal antibody was conjugated with a ligand (e.g., biotin), we furthermore found that the enhancement could be suppressed by an antiligand antibody (AbL). When free ligand molecules are added to the system, competition with L-MAbchi results to reduce the suppression of enhancement.

Construction of a human full-length cDNA bank

We aimed to construct a full-length cDNA bank from an entire set of human genes and to analyze the function of a protein encoded by each cDNA. To achieve this purpose, a multifunctional phagemid shuttle vector, pKA1, was constructed for preparing a high-quality cDNA library composed of full-length cDNA clones which can be sequenced and expressed in vitro and in mammalian cells without subcloning the cDNA fragment into other vectors. Using this as a vector primer, we have prepared a prototype of the bank composed of full-length cDNAs encoding 236 human proteins whose amino acid sequences are identical or similar to known proteins. Most cDNAs contain a putative cap site sequence, some of which show a pyrimidine-rich conserved sequence exhibiting polymorphism. It was confirmed that the vector permits efficient in vitro translation, expression in mammalian cells and the preparation of nested deletion mutants.

Characterization of monoclonal antibodies to chitinase A1 and enhancement of chitinase A1 activity by monoclonal antibodies

A total of eleven hybridomas which secrete antibodies against chitinase A1 were established. Among the eleven monoclonal antibodies (MAbs) obtained, six recognized the catalytic domain, three recognized the type III region and two recognized the chitin binding domain of chitinase A1. Of the two MAbs which recognized the chitin binding domain one was found to also react with chitinase D, but none of the other MAbs which recognized either the type III region or the chitin binding domain reacted with chitinase D despite the extensive amino acid sequence similarity between both the type III and chitin binding domains of the two chitinases. Two of the eleven MAbs enhanced chitinase activity significantly, while the other MAbs did not have any significant effect on chitinase A1 activity.

[Aortic dissection with giant pseudoaneurysm as a rare late complication of aortic valve replacement--a case report]

A 60-year-old man who had received aortic valve replacement for aortic regurgitation at 47 years of age developed sudden syncope and shock on Mar. 28, 1991. Close examination including CT scan and aortography revealed DeBakey type I aortic dissection with giant pseudoaneurysm which compressed superior vena cava and right pulmonary artery and caused superior vena cava syndrome. He underwent elective ascending aortic replacement under profound hypothermic cardiopulmonary bypass and circulatory arrest on Jun. 17, 1991. The giant pseudoaneurysm was present posterolaterally to the ascending aorta. It communicated with the false lumen and contained massive thrombi. The intimal tear of the ascending aorta existed along the suture line of previous aortotomy.

Astrovirus as a cause of gastroenteritis in Japan

We used an enzyme immunoassay (EIA) to screen for astrovirus in stool specimens from outbreaks and sporadic cases of gastroenteritis collected between 1982 and 1992 in six prefectural public health institutes in Japan. Three outbreaks of gastroenteritis involving schoolchildren and adults were confirmed to be attributable to astrovirus. Astrovirus was detected in 6 to 10% of the specimens from patients with sporadic gastroenteritis from whom no other bacterial or viral agent had been identified. Among the sporadic cases, astrovirus was most frequently detected in infants less than 1 year of age, and the incidence peaked in March and April. Using specimens from recent outbreaks, we found that the EIA was more sensitive than electron microscopy (EM) for the detection of astrovirus, and many EM-negative specimens were positive by EIA. However, some stool specimens previously found to have astrovirus-like particles by EM were negative by EIA, perhaps because of inadequate storage conditions, such as long-term storage and repeated freezings and thawings. Our results indicate that astrovirus is more commonly associated with childhood gastroenteritis than has been previously appreciated and suggest that further studies to examine the epidemiology and disease burden of this virus are needed.

The roles of the C-terminal domain and type III domains of chitinase A1 from Bacillus circulans WL-12 in chitin degradation

The mature form of chitinase A1 from Bacillus circulans WL-12 comprises a C-terminal domain, two type III modules (domains), and a large N-terminal domain which contains the catalytic site of the enzyme. In order to better define the roles of these chitinase domains in chitin degradation, modified chiA genes encoding various deletions of chitinase A1 were constructed. The modified chiA genes were expressed in Escherichia coli, and the gene products were analyzed after purification by high-performance liquid chromatography. Intact chitinase A1 specifically bound to chitin, while it did not show significant binding activity towards partially acetylated chitosan and other insoluble polysaccharides. Chitinases lacking the C-terminal domain lost much of this binding activity to chitin as well as colloidal chitin-hydrolyzing activity. Deletion of the type III domains, on the other hand, did not affect chitin-binding activity but did result in significantly decreased colloidal chitin-hydrolyzing activity. Hydrolysis of low-molecular-weight substrates, soluble high-molecular-weight substrates, and insoluble high-molecular-weight substrates to which chitinase A1 does not bind were not significantly affected by these deletions. Thus, it was concluded that the C-terminal domain is a chitin-binding domain required for the specific binding to chitin and that this chitin-binding activity is important for efficient hydrolysis of the sufficiently acetylated chitin. Type III modules are not directly involved in the chitin binding but play an important functional role in the hydrolysis of chitin by the enzyme bound to chitin.

[Adjunctive methods for surgery of descending thoracic aortic aneurysm]

During the last 6 years, we employed partial extracorporeal circulation (PEC) in 7 cases and left heart bypass (LHB) in 9 cases as adjunctive methods for surgery of descending thoracic aortic aneurysm. During the aortic clamping, systemic heparinization was performed to keep an ACT more than 400 seconds in a PEC group, while it was kept from 200 to 250 seconds in LHB group. The bypass flow was controlled to maintain the distal arterial pressure over 50 mmHg in both groups. Hemodynamics during the aortic clamping were stable in both groups and significant differences were not found between them. However, ventricular fibrillation occurred in one case of LHB group, who suffered from coronary artery disease, and required subsequent PEC to maintain systemic circulation. Both PEC and LHB provided adequate intraoperative hemodynamics and postoperative serum biochemistries. But we preferred to adopt PEC to maintain the diatal perfusion in cases with heart disease, who are likely to develop circulatory deterioration under the aortic clamping.

Fast and highly parallel content addressing of a large amount of information recorded in a holographic memory

It has recently become possible to fabricate spatial light modulators for holographic information retrieval. We analyze the signal-to-noise ratios in two typical holographic information retrieval systems, serial and inverted, and we discuss the possibilities of implementing holographic information retrieval with a newly proposed spatial light modulator that uses a Fabry-Perot étalon with a piezoelectrically driven mirror.

Long-term results of primary closure for ventricular septal defects in the first year of life

The long-term results of primary closure for large ventricular septal defects (VSDs) in infants under 1 year of age with severe symptoms were studied over a period of more than 10 years. Between January, 1971 and March, 1982, 49 infants underwent primary closure of a VSD through a right ventriculotomy using complete cardiopulmonary bypass with mild hypothermia. There were four hospital deaths but no late deaths. Two of four infants with residual shunts had a left ventricular-right atrial shunt which necessitated reoperation. Surgical heart block occurred in two infants who recovered sinus rhythm in the late period. The cardiothoracic ratio decreased from 60.5% preoperatively to 50.6% in the late postoperative period. Examination by cardiac catheterization revealed that the pulmonary-to-systemic pressure ratio (Pp/Ps) of 23 patients with a Pp/Ps of over 0.75 fell from 0.89 +/- 0.09 preoperatively to 0.42 +/- 0.12 by 1 month postoperatively, then to 0.27 +/- 0.05 in the late postoperative period. The latest values for the cardiac index and left ventricular ejection fraction were 3.4 l/min per m2 and 64.4%, respectively. More than 10 years after their operation, all the survivors were growing normally and maintaining a good quality of life, which supports our recommendation that primary repair should be performed in the first year of life for infants with large VSDs.

[Conduction disturbances after coronary artery bypass grafting with retrograde cardioplegia]

We studied forty-six cases, who had undergone coronary artery bypass grafting with retrograde cold blood cardioplegia for myocardial protection, to manifest the frequency and causative factors of postoperative conduction disturbances. We obtained the following conclusions. 1) Postoperative conduction disturbances developed in nineteen cases (41.3%), all of which were right bundle branch blocks, but these were usually transient and were not associated with further complications in the follow-up period. 2) There were no significant differences in many factors, including number of grafts, aortic cross-clamp times, or peak CK-MB between cases with and without postoperative conduction disturbances.