Studies on the inhibition of pancreatic and carboxylester lipases by protamine

The basic protein protamine strongly inhibited hydrolysis of triolein emulsified with soybean phosphatidylcholine (PC) by pancreatic and carboxylester lipases; 10 micrograms/ml protamine, about 1000 times lower than the concentration of bovine serum albumin for the same effect, inhibited triolein hydrolysis completely. This inhibition was not affected by the incubation pH or bile salt concentration. Two other basic proteins, histone and purothionin, also inhibited hydrolysis of triolein emulsified with soybean PC, but they did not inhibit triolein hydrolysis by gastric lipase. When gum arabic was used as an emulsifier instead of soybean PC, these basic proteins did not affect triolein hydrolysis by pancreatic or carboxylester lipases. The effects of protamine on triolein hydrolysis by pancreatic and carboxylester lipases was studied using various phospholipids as emulsifiers. Protamine (10 micrograms/ml) did not inhibit hydrolysis of triolein emulsified with dicaproyl PC (DCPC), phosphatidic acid (PA), or phosphatidylserine (PS) by pancreatic and carboxylester lipases. Conversely, protamine at high concentrations slightly stimulated hydrolysis of triolein emulsified with DCPC or PA. Hydrolysis of triolein-phosphatidylethanolamine (PE) emulsion was inhibited slightly by protamine. The profiles of protamine inhibition of triolein-phosphatidyl-N,N-dimethyl ethanolamine (PDME) and triolein-phosphatidyl-N-monomethyl ethanolamine (PMME) emulsions were intermediate between those of PC and PE emulsions. These results suggest that the phospholipid species, especially choline moieties and fatty acid chain length, affect the lipase inhibitory activity of protamine profoundly. In vivo, oral administration of protamine to rats reduced and delayed the peak plasma triacylglycerol concentration, but neither bovine serum albumin nor an amino acid mixture with an amino acid composition identical to protamine affected plasma triacylglycerol levels.

Numerical simulation of nonpulsatile left ventricular bypass

A computer simulation was carried out to investigate the influence of nonpulsatile left ventricular assistance on hemodynamics. A simulation circuit was constructed to represent the circulatory system. A source of current was added to denote the nonpulsatile blood pump. The left and right ventricles were replaced by variable compliances. Left heart failure was simulated by decreasing the amount of compliance change of the left ventricle. We introduced a pulsatility indicator (PI) to clarify the pulsatility characteristics in the hemodynamics; this PI was defined as the ratio of the pulse pressure (PP) to the mean aortic pressure (AoP). When nonpulsatile bypass flow increased, the mean AoP, tension time index (TTI), and diastolic pressure time index (DPTI) increased, and cardiac output, PP, and PI decreased. When assisted flow increased with the constant total flow rate, the mean AoP and DPTI changed little; the PP, TTI, and PI decreased, and the endocardial viability rate increased. The PI would be helpful in evaluating the effect of pulsatility.

[Efficacy of left atrial only procedure for the treatment of chronic atrial fibrillation associated with mitral valve disease]

We supposed that chronic atrial fibrillation originated as a result of discontinuity of the refractory period of the dilated left atrium in the mitral valvular disease. We then performed left atrial only procedures to treat the chronic atrial fibrillation (AF) associated with mitral valve disease. These procedures were the left atrial isolation and the modified left sided maze procedure, consisting of isolation of all pulmonary veins and cryoablation to the posterior wall of the left atrium, in addition to excision of the left atrial appendage. Twenty-eight patients underwent these procedures over the past thirty months. Patient ages and the duration of AF ranged from 37 to 71 years and from 0.5 to 26 years, with an average of 8.3 years, respectively. Chronic AF disappeared in twenty-four patients (86%) at discharge. Three patients with severe tricuspid insufficiency had sustained AF and one patient had atrial flutter postoperatively. Three patients showed sick sinus syndrome postoperatively and two of these required a DDD pacemaker. Severe tricuspid regurgitation (p < 0.020) was the factor in recurrence of AF. Left atrial only procedures were effective in the treatment of chronic AF associated with mitral valvular disease.

Novel NTP binding property of rice dwarf phytoreovirus minor core protein P5

Rice dwarf phytoreovirus (RDV) mRNA synthesized from purified virion has a cap structure, m7GpppAm-, which suggests the presence of guanylyltransferase activity in the virion. We attempted to identify the enzyme involved in the cap formation by using a nucleoside triphosphate binding assay. Incubation of virion with [alpha-32P]GTP resulted in labeling of an 89-kDa protein that had not previously been identified in purified virus preparations. Interestingly this protein also covalently bound UTP and ATP, which is not a property of the known guanylytransferases. RDV particles catalyzed GTP-PPi, dGTP-PPi, ATP-PPi, and UTP-PPi exchange reactions. In SDS-polyacrylamide gel electrophoresis, the 89-kDa protein comigrated with the S5-coded protein, P5, which had been expressed by a baculovirus vector. Moreover, the labeled 89-kDa protein was precipitated by an antiserum against this recombinant RDV P5. Careful reinvestigation of purified virus particles by SDS-polyacrylamide gel electrophoresis and Western blotting analyses showed that they contained a small amount of P5 (<0.5% of the total protein) within the core. These results may suggest that the minor core protein of RDV, which is coded by S5, is a candidate guanylyltransferase, although the biological significance of its ATP and UTP binding activities remains largely unknown.

Pooled air in open heart operations examined by transesophageal echocardiography

BACKGROUND

The clinical significance of pooled air detected by transesophageal echocardiography during open heart operations is not clear.

METHODS

Thirty-eight consecutive patients undergoing an open heart operation or an operation on the ascending aorta were divided into two groups on the basis of the absence (group 1, n = 14) or presence (group 2, n = 24) of pooled air. They were examined for intramyocardial echo contrast, ST segment elevation, conduction disturbances, and regional wall motion abnormalities.

RESULTS

Echo contrast was found in no patient in group 1 and 66.7% of group 2 patients (p < 0.001). New regional wall motion abnormalities were detected in no patient in group 1 versus 33.3% of group 2 patients (p < 0.05), and ST segment elevation was seen in 33.3% of group 2 patients versus no group 1 patients (p < 0.05). Intramyocardial cardial echo contrast was newly detected after the appearance of pooled air more frequently in patients with ST segment elevation (p < 0.001). Atrioventricular block and sinus arrest appeared in 3 patients and 2 patients, respectively. Postoperative regional wall motion abnormalities were found in 25.0% of patients and were not closely related to intraoperative echo contrast findings.

CONCLUSIONS

Pooled air, which is often detected in open heart operation by means of transesophageal echocardiography, is related to several cardiac events, including ST segment elevation, conduction disturbances, and regional wall motion abnormalities, although most of these are transient.

Rom1p and Rom2p are GDP/GTP exchange proteins (GEPs) for the Rho1p small GTP binding protein in Saccharomyces cerevisiae

The RHO1 gene encodes a homolog of the mammalian RhoA small GTP binding protein in the yeast Saccharomyces cerevisiae. Rho1p is localized at the growth site and is required for bud formation. Multicopy suppressors of a temperature-sensitive, dominant negative mutant allele of RHO1, RHO1(G22S, D125N), were isolated and named ROM (RHO1 multicopy suppressor). Rom1p and Rom2p were found to contain a DH (Dbl homologous) domain and a PH (pleckstrin homologous) domain, both of which are conserved among the GDP/GTP exchange proteins (GEPs) for the Rho family small GTP binding proteins. Disruption of ROM2 resulted in a temperature-sensitive growth phenotype, whereas disruption of both ROM1 and ROM2 resulted in lethality. The phenotypes of deltarom1deltarom2 cells were similar to those of deltarho1 cells, including growth arrest with a small bud and cell lysis. Moreover, the temperature-sensitive growth phenotype of deltarom2 was suppressed by overexpression of RHO1 or RHO2, but not of CDC42. The glutathione-S-transferase (GST) fusion protein containing the DH domain of Rom2p showed the lipid-modified Rholp-specific GDP/GTP exchange activity which was sensitive to Rho GDP dissociation inhibitor. These results indicate that Rom1p and Rom2p are GEPs that activate Rho1p in S.cerevisiae.

[A case report of bypass grafting for coronary atherosclerosis with anomalous origin of the left coronary artery from the right coronary artery ostium-anterior subtype]

A 73-year-old female began to suffer from effort-induced chest pain and later disabling angina pectoris. Coronary angiographic evaluation disclosed that both the right and left coronary arteries originated from the right sinus of Valsalva. The dominant right coronary artery had a normal course with a 90% narrowing in the first segment. The left main trunk crossed anteriorly the pulmonary artery conus, thereafter dividing into the left anterior descending and circumflex coronary arteries with two 99% narrowings in the seventh and eleventh segment. She underwent bypass of the left anterior descending and right posterior descending coronary arteries with the left interthoracic artery, the right gastroepiploic artery, and saphenous vein graft on cardiopulmonary bypass support. The postoperative course was uncomplicated.

Risk factors for hepatitis C virus infection among blood donors in an HIV-epidemic area in Thailand

OBJECTIVE

The role of sexual transmission in hepatitis C virus (HCV) infection has not yet been completely elucidated. This study aimed to compare the risk factors for HCV and human immunodeficiency virus (HIV) infection in an HIV epidemic area of Thailand where HIV is mainly transmitted heterosexually.

DESIGN AND SUBJECTS

Sera from 3053 blood donors were collected and tested for HCV and HIV between January and March 1994. Altogether 1756 (57.5%) of the donors were interviewed about demographics and several risk factors.

RESULTS

The prevalence rates of HIV and HCV infections determined by antibody assays were 2.3% and 2.2%, respectively. Sexual risk factors were clearly shown among anti-HIV positive donors. These clear associations were not found, however, among anti-HCV positive donors. In contrast, previous histories of injecting drug use and being tattooed were found in some anti-HCV positive donors but less frequently in anti-HIV positive donors.

CONCLUSIONS

Sexual transmission may play a relatively minor role in HCV transmission compared with HIV, in this area.

The Arabidopsis ERECTA gene encodes a putative receptor protein kinase with extracellular leucine-rich repeats

Arabidopsis Landsberg erecta is one of the most popular ecotypes and is used widely for both molecular and genetic studies. It harbors the erecta (er) mutation, which confers a compact inflorescence, blunt fruits, and short petioles. We have identified five er mutant alleles from ecotypes Columbia and Wassilewskija. Phenotypic characterization of the mutant alleles suggests a role for the ER gene in regulating the shape of organs originating from the shoot apical meristem. We cloned the ER gene, and here, we report that it encodes a putative receptor protein kinases. The deduced ER protein contains a cytoplasmic protein kinase catalytic domain, a transmembrane region, and an extracellular domain consisting of leucine-rich repeats, which are thought to interact with other macromolecules. Our results suggest that cell-cell communication mediated by a receptor kinase has an important role in plant morphogenesis.

The protective effect of low power He-Ne laser against erythrocytic damage caused by artificial heart-lung machines

We studied the protective effects of low power He-Ne laser irradiation on erythrocytes against the damage caused by experimental artificial heart-lung machines. The erythrocyte suspension in a closed circuit was perfused with a roller pump. One of two circuits was used for laser treatment and the other for control. The laser group demonstrated significantly higher erythrocyte deformability and erythrocyte ATP levels, and lower free hemoglobin and lipid peroxide levels. A laser output power of 8.5 mW was most effective in protecting the erythrocytes. A further morphological finding using a scanning electron microscope showed fewer echinocytes and more discocytes in the laser group. This finding was consistent with the results of physiological and biochemical tests. Low power He-Ne laser irradiation was shown to protect human erythrocytes from the damage caused by an experimental artificial heart-lung machine, raising the possibility of the clinical application of low power He-Ne laser treatment during extracorporeal circulation in cardiovascular surgery.

Early cervical neoplasia confirmed by conization: diagnostic accuracy of cytology, colposcopy and punch biopsy

OBJECTIVE

To investigate the accuracy rates of cytology, colposcopy and punch biopsy in early cervical neoplasia confirmed by conization.

STUDY DESIGN

During the 10 years from 1984 to 1993, cold knife conization was performed on 151 patients with early cervical neoplasia proven by punch biopsy at our department. The accuracy rates of cytology, colposcopy and punch biopsy were investigated.

RESULTS

The accuracy rates of cytology, colposcopy and punch biopsy were 52% (78 of 151), 66% (100 of 151) and 66% (100 of 151), respectively.

CONCLUSION

These results suggest that a composite diagnosis with cytology, colposcopy and punch biopsy is necessary for a correct evaluation. Early cervical neoplasms are frequently seen in young women, and conservative procedures, such as conization, cryosurgery and laser vaporization, are the treatments of choice in order to preserve reproductive function. We recommend conization as the best conservative procedure, with preservation of reproductive function.

[The combination therapy with vinca-alkaloid slow infusion and cholchicine was effective to refractory idiopathic thrombocytopenic purpura. The patient could receive femoral head replacement in safety]

A 46-year-old man with idiopathic thrombocytopenic purpura (ITP) refractory to corticosteroid, splenectomy and other drugs was admitted to our hospital in August, 1994, because of aseptic necrosis of the right femoral head. Although high-dose intravenous gamma-globulin was ineffective, the platelet count was increased within two weeks by the combination therapy that consisted of 0.02 mg/kg vincristine alternating with 0.1 mg/kg vinblastine by slow infusion at a 1-week interval, and oral 1.5 mg/day colchicine. He subsequently underwent the femoral head replacement. This combination therapy seems to be useful for refractory ITP in preparation for surgery.

In vitro and in vivo testing of an implantable motor-driven left ventricular assist device

A totally implantable motor-driven left ventricular assist device (LVAD) has been developed and tested. The performance of this LVAD was tested in a mock circulatory system. This pump provided 8 L/min of output against a mean afterload of 120 mm Hg with a filling pressure of 20 mm Hg when the pump was operated in the fill/empty mode. The right and left pumps were tested in a mock loop. The right pump afterload was kept in the range from 23-32 mm Hg. With increase in the left pump afterload, the pump power output varied from 1.64 to 2.37 W. The instantaneous motor power input varied from 22.6 to 30.6 W with the total system efficiency ranging from 6.7 to 9.4%. To date, 4 in vivo studies have been conducted for up to 12 h. Two animals survived 12 and 10 h, respectively. Termination was due to bleeding in 1 animal, vent tube obstruction in 1, and respiratory failure in 2. All animals died of technical failure. Another experiment is to be undertaken, and a newly designed cannula is now being manufactured.

Coronary artery fistula to bronchial artery on contralateral side of coronary atherosclerosis and myocardial insufficiency. A case report

Among coronary vessels anomalies is the rare coronary artery fistula. Myocardial insufficiency resulting from fistula steal phenomenon can not be clinically distinguished from that of coronary atherosclerosis, if these conditions coexists in the same patient. The authors present a case of extracardiac left coronary artery fistula connecting the circumflex branch and left bronchial artery, with inferior wall myocardial insufficiency attributable to the right coronary artery atherosclerosis.

[Lupus anticoagulants in patients with systemic lupus erythematosus]

Lupus anticoagulants (LA) and anticardiolipin antibodies (aCL) are known as thrombosis-related antiphospholipid antibodies. LA is not as well characterized as aCL, and the relation between LA and aCL is not clarified. Since standardized method for the detection of LA has not been established, we measured LA activities in outpatients with SLE by using two different methods (KCT and dRVVT), and analyzed the characteristics of LA in SLE. LA was detected in 29.8% of all samples (14.3% in both methods, 15.5% in one method). IgG-aCL and IgM-aCL was detected in 38% and 20%, respectively, of all LA positive samples. Though a good correlation was observed between LA activities and IgG-aCL levels, a considerable number of LA positive samples were negative for aCL. This indicated the presence of factors with LA activity other than aCL. On the contrary there was also a high percentage of LA negative samples with positive aCL (42.4% in IgG-aCL, 47.4% in IgM-aCL), suggesting the presence of aCL with poor or low LA activity. These findings showed the heterogeneity of antiphospholipid antibodies both in LA and in aCL. The platelet function tests showed increased platelet adhesiveness and normal platelet aggregation in LA positive patients with SLE even in the inactive phase. The serum levels of factors such as protein C, protein S, antithrombin III and thrombomodulin were within normal range. Clinical features such as hemolytic anemia, thrombosis and abortion were more frequently observed in LA positive population than in LA negative population. The clinical features tend to be different between patients with dRVVT-LA and those with KCT-LA, though not significant. Because of the heterogeneity in LA, a combination of more than two different methods including dRVVT was recommended for the detection and the evaluation of LA.

Induction of antibodies against structural proteins of hepatitis C virus in mice using recombinant adenovirus

Replication-deficient recombinant adenoviruses expressing structural proteins of hepatitis C virus (HCV) were constructed. Each recombinant lacks adenoviral E1A and E3 genes and bears expression units for HCV structural proteins. The expression units contain HCV cDNAs coding for either the protein or core, one of two envelopes (E1 and E2) or all of these structural proteins (core, E1 and E2) under the control of the SR alpha promoter. In HeLa or HepG2 cells, the recombinants can express efficiently HCV genes after infection without replication of the recombinants. We detected 22-kDa core, 35-kDa E1 and 58-kDa E2 proteins of HCV in these cells. The recombinant expressing all three HCV structural proteins was inoculated into mice. Antibodies to each of the three HCV proteins were detected in all of the ten mice tested. The results indicate that the recombinant adenoviruses efficiently express HCV genes and induce specific antibody against the expressed HCV proteins in animals.

[Resolution of psoriasis vulgaris following allogeneic bone marrow transplantation for aplastic anemia]

A 36 year-old man had suffered from psoriasis vulgaris for about 25 years. He had received corticosteroids ointment and PUVA therapy with partial response. In 1987, he was diagnosed as having aplastic anemia (AA) and treated with various medications, but failed to respond. He received an allogeneic bone marrow transplantation (BMT) from his histocompatible sister in 1993. Conditioning regimen of BMT consisted of total lymphoid irradiation (7.5 Gy) and cyclophosphamide (200 mg/kg). Cyclosporin A and methotrexate were given for prophylaxis of graft-versus-host disease. On day 24, bone marrow examination disclosed normocellular marrow and karyotypic analysis completely confirmed the donor's origin. Before BMT, he had systemic psoriatic plaques with scales, together with nail involvement. After BMT, psoriatic plaques disappeared and nail deformity improved. He has remained in remission of his AA and completely free of psoriasis in the absence of immunosuppressive or other treatments. The cause of psoriasis is thought to be an immune-mediated disorder. Our case supports the observation that changing the host's immune system through allogeneic BMT can achieve remission of psoriasis. It is suggested that allogeneic BMT may be one strategy for the treatment of intractable immune-mediated disorders.

A modified maze procedure performed only on the left atrium for chronic atrial fibrillation associated with mitral valve disease: report of a case

We describe herein the successful treatment of a patient with chronic atrial fibrillation (AF) associated with mitral valve stenosis and regurgitation, achieved by performing a modified maze procedure on the left atrium alone. The patient was a 51-year-old man who had suffered from intractable AF for 17 years, causing multiple cerebral emboli and palpitations. He had undergone open mitral commissurotomy and balloon commissurotomy 15 and 7 years ago, respectively. On admission, an echocardiogram revealed mitral valve restenosis and thrombosis in the left atrial appendage. Prosthetic valvular replacement was performed following isolation of all pulmonary veins with cryoablation to the posterior wall of the left atrium and excision of the left atrial appendage. Postoperatively, the AF disappeared and echocardiogram demonstrated a left atrial kick in the mitral valvular inflow without any evidence of thrombosis in the left atrium. Thus, we believe that our modified "left side only" maze procedure is a simple and efficient method for the treatment of chronic AF with mitral valve disease.

Methanol traps the troponin-tropomyosin-actin complex in an "off-state"

We have investigated the effect of methanol at concentrations below 15% (v/v) on acto-heavy meromyosin (HMM)- and tropomyosin (Tm)-troponin (Tn)-acto-heavy meromyosin-ATPase activities. Methanol slightly enhanced ATPase activity of acto-HMM alone. It had no apparent effect on normalized Tm-Tn-acto-HMM-ATPase activity in the absence of Ca2+. In the presence of Ca2+, however, methanol markedly inhibited normalized Tm-Tn-acto-HMM ATPase activity. These results show that methanol affects the troponin-tropomyosin regulation of acto-HMM ATPase: methanol suppresses the Ca(2+)-sensitivity of the regulatory system and traps it in an "off-state."

Expression of hepatitis C virus envelope proteins in transgenic mice

In an attempt to establish a model for hepatitis C virus (HCV) infection, we produced mice transgenic for the HCV envelope genes, E1 and E2, under the control of a regulatory element from hepatitis B virus. F1-generation mice from the established founders demonstrated expression of both E1 and E2 proteins as glycosylated forms in their organs including the liver. Immunostaining revealed the localization of envelope proteins principally in the cytoplasm of hepatocytes around the hepatic central veins. Furthermore, E1 and E2 proteins were shown by immunoprecipitation to be associated with each other in the mouse liver. There was no evidence of tissue pathology in the mouse liver up to 16 months of age, suggesting that E1 and E2 proteins per se may not have direct pathogenic effects. Our results demonstrate the first successful expression of HCV gene products in the mouse liver and the association of in vivo expressed HCV envelope proteins. This transgenic mouse would be a good model to study the virus-cell interactions of HCV such as intracellular transport and assembly of envelope proteins. Also it may be a good model system to determine the role of these proteins in the pathogenesis of hepatitis or extra-hepatic manifestations in HCV infection by the introduction of cytotoxic T lymphocytes specific for the envelope proteins.

Proteolytic activity of NS3 serine proteinase of hepatitis C virus efficiently expressed in Escherichia coli

The serine proteinase of hepatitis C virus (HCV) non-structural protein NS3 was efficiently expressed in an active form as a fused protein with oligohistidine in Escherichia coli. The recombinant fusion protein was purified to near homogeneity by affinity chromatography on a metal chelation column. Trans-cleavage activity of this protein was investigated by using the substrate NS5 protein expressed in insect cells. The purified serine proteinase trans-cleaved the partially purified NS5 protein. In contrast, the NS3 proteins with mutations at the proposed catalytic site, Ser1165 or His1083, lost the trans-cleavage activity. Analysis of the authentic enzyme and variants with site-directed mutations provides a useful tool for understanding the structure-function relationship of the NS3 serine proteinase. We then developed an in vivo trans-cleavage assay system by coexpression of the NS3 proteinase and the NS5 substrate in E coli, and examined the effect of known inhibitors of serine proteinase. Inhibition of its proteolytic activity by N-p-tosyl-L-lysine chloromethyl ketone (TLCK) was observed, but only at high concentrations. The in vitro and in vivo trans-cleavage assays for NS3 serine proteinase will facilitate efficient testing for inhibitors of the replication of HCV and specific treatment for hepatitis C.