Synthesis and in vitro cytotoxicity of 3- or 4-dialkylaminomethyl-1-azaanthraquinones

Six 3-dialkylaminomethyl-1-azaanthraquinones and five 4-dialkylaminomethyl-1-azaanthraquinones were synthesized and evaluated in vitro cytotoxicity against four human cancer cell lines. The compounds retained much of their cytotoxic activity against the multi-drug-resistant cell line (KB-V-1) as shown by resistance index.

Molecular cloning and analysis of transcription initiation in the Anagrapha falcifera multiple nucleocapsid polyhedrosis virus polyhedrin gene

Using Autographa californica multiple nucleocapsid polyhedrosis virus (AcMNPV) polyhedrin to probe the Southern blots of Anagrapha falcifera multiple nucleocapsid polyedrosis virus (AfMNPV), we identified the location of the AfMNPV polyhedrin gene within the 7.2 kb EcoRI fragment. The 7.2 kb EcoRI fragment of AfMNPV was cloned and the nucleotide sequences of the polyhedrin coding region and its flanking regions were determined. Nucleotide sequence analysis indicated the presence of an open reading frame (ORF) of 735 nucleotides (nt) which could encode 245 amino acids with a predicted molecular mass of 29 kDa. The nucleotide sequences within the coding region of the AfMNPV polyhedrin shared 80% similarity with the polyhedrin gene from AcMNPV but were most closely related to Bombyx mori NPV with 92% sequence identity. The size of the AfMNPV polyhedrin mRNA, determined by the Northern blot analysis, was estimated to be 1200 nt. The consensus promoter sequence (ATAAG) for the baculovirus very late gene was also observed. Two degenerate poly(A) tailing signals were found immediately downstream of the translational stop codon. The transcription initiation site, mapped by primer extension analysis, was found to be at T located 24 nt upstream from the A of the translation initiation codon. This site is located 26 nt downstream from the second A of the consensus TAAG, the transcription initiation site of most other NPVs.

Developmental association of the beta-galactoside-binding protein galectin-1 with the nuclear matrix of rat calvarial osteoblasts

The protein composition of the nuclear matrix changes significantly as the osteoblast matures from a proliferating pre-osteoblast to an osteocyte embedded in a mineralized matrix. These matrix protein are the result of developmental stage-specific gene expression during osteoblast differentiation. To isolate nuclear matrix proteins unique to the bone phenotype we analyzed nuclear matrix preparations from cultures of rat calvarial osteoblasts by high resolution two-dimensional gel electrophoresis at two different stages: proliferation (day 3) and differentiation (day 18, mineralized). We characterized one protein (14 kDa; pI 5.0), that was detectable only in the nuclear matrix of differentiated osteoblasts. By mass spectrometry and microsequencing, this protein was identified as the beta -galactoside-binding protein galectin-1. Both immunofluorescence staining of nuclear matrix preparations with the galectin-1 antibody and western blot analysis of subcellular fractions confirmed that galectin-1 is only associated with the nuclear matrix in differentiated osteoblasts as the result of differential retention. Galectin-1 protein and mRNA are present throughout osteoblast differentiation. Galectin-1 is present in the cytoplasmic and nuclear fractions in both proliferating and differentiated osteoblasts. However, its only stable binding is to the nuclear matrix of the differentiated osteoblast; but, in proliferating osteoblasts, galectin-1 is not retained in the nuclear matrix. Taken together, our results suggest that developmental association of galectin-1 with the nuclear matrix reflects differential subnuclear binding of galectin-1 during osteoblast differentiation.

Morphology of tricuspid valve in pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PAIVS) is a rare congenital cardiac anomaly that has been classified into two types: one is a more frequent type having dysplasia of tricuspid valve (TV) with a small annulus, underdeveloped right ventricle (RV) with a hypoplastic cavity and a hypertrophic wall; the other type has severe dysplasia of TV and dilatation of RV, right atrium (RA), and right atrioventricular junction with thinning of the RV wall. We performed a morphologic study on 11 autopsied hearts with PAIVS, giving particular emphasis to the variation of morphology of the TV. We could classify these hearts into 3 groups according to the degree of right ventricular development. In the first group of 7 cases (type I), the RVs were underdeveloped. Thick leaflets, restricted valve apparatus with short chordae, and small annuli were characteristics of the TV. In the second group of 3 cases (type II), the RVs showed marked enlargement of the cavity and thinning of the wall. The TV showed redundant, dysplastic, sail-like anterior leaflets, and the downward displacement of septal leaflet and/or posterior leaflet, which are the findings frequently observed in Ebstein's malformation. The RVs were dilated and with partially unguarded tricuspid orifice. The septal leaflet of the TV was dysplastic and, in two cases, the septal leaflet showed chordal structure at the upper surface facing the RA, which is a peculiar finding that has not been described in the literature. The remaining case was a heart with a moderately developed RV (type III). The TV showed mildly dysplastic appearance and we classify this as a separate type, because we could expect the best surgical results in this type. This type had optimal size of RV and the mildest degree of dysplasia of TV. In PAIVS, the morphology of TV correlates well with the type of the right ventricular development.

Aging and cerebrovascular disease

Aging influences cerebrovascular disease expression by a variety of mechanisms. Age-related changes in cerebral autoregulation, cellular metabolism, the blood-brain barrier, and autonomic function may leave the cerebrovascular system vulnerable to injury. Certain cerebrovascular disease, such as atrial fibrillation, watershed infarctions, carotid artery atherosclerosis, cerebral hemorrhages, subdural hematomas, and transient global amnesia manifest in the elderly. Vascular dementia and white matter disease are better understood with newer neuroimaging studies, careful neuropsychological and histopathologic examinations. Atherosclerosis and cerebral amyloid angiopathy may have larger roles than previously understood in Alzheimer's disease.

Relationship between global cytosolic Ca2+ concentration and Ca2+-activated K+ current in rabbit cerebral arterial myocyte

In smooth muscle cells, the sarcoplasmic reticulum (SR) has been identified as the primary storage site for intracellular Ca2+. The peripheral SR is in close proximity with plasma membrane to make a narrow subsarcolemmal space. In this study, we investigated the regulation of subsarcolemmal [Ca2+] ([Ca2+]sl) and global cytosolic [Ca2+] ([Ca2+]c) of rabbit arterial smooth muscle using whole cell patch clamp technique and microspectrofluorimetry. The Ca2+-activated K+ current (IK(Ca)) and the ratio of fura-2 fluorescence (R340/380) were considered to reflect the [Ca2+]sl and [Ca2+]c, respectively. At a holding potential of 0 mV, extracellular application of 10 mM caffeine, a well known Ca2+-releasing agent, induced transient increase of IK(Ca) and R340/380 (IK(Ca)-transient and R340/380-transient, respectively). The increase and decay of IK(Ca) transient was faster than R340/380-transient. By repetitive application of caffeine, when the refilling state of SR was supposed to be lower than the control condition, IK(Ca)-transient and R340/380 transient were suppressed to different levels; e.g. the second application 20 sec after the first could induce smaller IK(Ca) transient than R340/380-transient. Dissociation of IK(Ca)-transient and R340/380-transient was removed by sufficient (>3 min) washout of caffeine. Recovery from the dissociation was also dependent upon the membrane potential; faster recovery was observed at negative (-40 mV) holding potential than at depolarized (0 mV) condition. Dissociation of IK(Ca) from [Ca2+]c was also partially prevented by perfusion with Na+-free (replaced by NMDG+) extracellular solution. These results suggest that, 1) there is prominent spatial inhomogeneity of [Ca2+] in cerebral arterial myocyte, 2) [Ca2+]Sl is preferentially affected by the interference from nearby plasmalemmal Ca2+ regulation mechanism which is partly dependent upon extracellular Na+.

Detection of antibodies against DNA polymerase of hepatitis B virus in HBsAg-positive sera using ELISA

OBJECTIVES

DNA polymerase (pol) of Hepatitis B virus (HBV) includes 3 different domains such as terminal protein (TP), reverse transcriptase (RT) and RNase H. Humoral immune responses to each of these proteins have not been well documented previously, although antibody to pol was detected in serum of patients with chronic hepatitis B. We have constructed TP (amino acids 1-182), RT (amino acids 346-685) and RNase H (amino acids 690-832).

METHODS

By ELISA using each protein expressed in E. coli as antigens, the corresponding antibodies were tested in serum from 40 patients with type B viral chronic liver diseases. (20 HBeAg-positive and 20 HBeAg-negative). As negative controls, sera from 3 healthy young men were used. With the mean values of the OD, which were tested 4 times per each test sample and 3 times per each control sample, we considered to be positive if the mean OD of each test sample is 2-fold or higher than that of controls.

RESULTS

Five of 40 sera (12.5%) contained one or two different antibodies detectable by this method: 4 of 20 HbeAg-positive sera (20%) and 1 of 20 HbeAg-negative sera (5%). Anti-TP, anti-RT and anti-RNase H antibodies were detected in 2.5% (1/40), 10% (4/40) and 7.5% (3/40), respectively. Among 4/20 HbeAg-positive ELISA-positive sera, anti-TP, anti-RT and anti-RNase H were positive in 5% (1/20), 20% (4/20) and 10% (2/20), respectively, while 1 HBeAg-negative ELISA-positive sera were positive only for anti-RNase H.

CONCLUSIONS

These results suggest that the corresponding antibody responses to individual recombinant peptides derived from 3 domains of DNA polymerase may tend to be detected more frequently in HBeAg-positive sera than in HBeAg-negative sera from various patients with type B viral chronic liver diseases.

Gating provides improved accuracy for differentiating artifacts from true lesions in equivocal fixed defects on technetium 99m tetrofosmin perfusion SPECT

BACKGROUND

Because equivocal fixed perfusion defects on single photon emission computed tomography (SPECT) often cause a diagnostic dilemma in patients with suspected coronary artery disease (CAD), we used receiver-operating characteristic (ROC) curve analysis to evaluate the degree of increased accuracy provided by adding gated images for interpretation of such cases.

METHODS AND RESULTS

One hundred five (29%) of 365 consecutive patients undergoing technetium 99m tetrofosmin gated SPECT for evaluation of CAD demonstrated an equivocal fixed defect. Two independent observers graded the probability for true lesion with a 5-point system over 3 steps of interpretation: reviewing tomographic images alone (step 1), adding projection images (step 2), and adding gated cine images (step 3). Based on clinical criteria, 66 patients were categorized as disease negative and 25 as disease positive, while the final diagnosis was undetermined in 14 cases. Diagnostic performance was significantly higher at step 3 than at step 1 for both observers (p < 0.05 and < 0.0001) and at step 2 for observer B (p < 0.005). The maximum accuracy increased from 78.0% to 80.2% at step 2 to 84.6% to 86.8% at step 3. Moreover, the agreement of interpretation between the 2 observers was higher at step 3 (kappa = 0.53) than at step 1 (kappa = 0.29) or step 2 (kappa = 0.25).

CONCLUSION

In patients showing an equivocal fixed defect on 99mTc tetrofosmin SPECT, gated cine images provide improved differential accuracy and enhanced objectivity of interpretation by reducing interobserver variance.

Molecular cloning of a novel GTP-binding protein induced in fish cells by rhabdovirus infection

We have cloned and sequenced a cDNA encoding GTP-binding protein from a fish cell, CHSE-214. The clone was 1493 bp long and contained an open reading frame encoding 364 amino acids. It has the five sequence motifs G1-G5 that are conserved in all GTP-binding proteins. Its amino acid sequences are strikingly different from those of the well-characterized G-proteins. However, sequences closely related to this protein are found in various kinds of species including human, Arabidopsis, Drosophila and archaebacteria, suggesting a novel subfamily within the superfamily of the GTP-binding proteins. Northern analysis indicates that this gene is constitutively expressed at a low level in normal cells but is induced by fish rhabdovirus infection at about 24 h post infection and disappears thereafter. Based on these observations, we propose that this protein represents an evolutionarily conserved novel subfamily of GTP-binding proteins which may play an important role in fish rhabdovirus infection.

Experience of orthotopic liver transplantation in 11 patients with liver cirrhosis from Korea: medical factors affecting outcome

Orthotopic liver transplantation (OLT) has evolved to become a standard treatment of choice for end-stage liver diseases. The present study was performed to evaluate the peri-operative medical factors affecting transplantation outcome and to determine if patients with type B viral cirrhosis were acceptable for OLT. A total of 11 patients with end-stage cirrhosis, who have received OLT in Kangnam St. Mary's Hospital since May 1993, included 8 HBV-related cases, 1 Hepatitis C Virus (HCV)-related case, and 2 non-B, non-C cases. One-year cumulative survival rate by Kaplan-Meier method was 43.7%. Factors significantly associated with 1-year survival of the recipients during pre-OLT period were performance status and modified Pugh-Child score (p=0.015 and p=0.015, respectively). Among those 4 patients who lived longer than 1 year, 3 of 4 patients with HBsAg-positive had no HBV re-infection with our protocol. These results suggest that, to improve the outcome of OLT in cirrhosis patients, transplantation should be performed in the stage when patients maintain better performance and hepatic functional reserve during the end-stage of liver cirrhosis. In addition, patients with cirrhosis caused by HBV infection may be indicated for OLT, because HBV re-infection is preventable effectively with a high-dose hepatitis B immunoglobulin protocol.

Mechanism of regulation of 8-hydroxyguanine endonuclease by oxidative stress: roles of FNR, ArcA, and Fur

We found previously that 8-hydroxyguanine (oh8Gua) endonuclease in E. coli is induced in response to oxidative stress in a fashion similar to the oxidative response of the Mn-superoxide dismutase (MnSOD). In this study, attempts were made to identify the genes involved in the co-regulation of E. coli endonuclease and MnSOD (sodA). oh8Gua nuclease is induced by molecular oxygen and a superoxide radical generator (paraquat) but not by H2O2, suggesting that the regulation of this endonuclease is dependent on SoxRS but independent of OxyR. This enzyme was induced by paraquat in all of the soxRS mutant strains used (soxR-, soxS- and soxRc), whereas glucose-6-phosphate dehydrogenase (a member of the soxRS regulon) showed the expected responses; therefore, this possibility was excluded. The presence of metal chelators in the growth medium caused the induction of this enzyme, and this induction was suppressed by the addition of Fe++. Consistent with this finding, this enzyme was expressed under anaerobiosis in all of the mutant strains of fnr in particular, as well as fur, arcA, and combinations thereof. These findings suggest that the oxidative regulation of oh8Gua endonuclease is under control of fnr, fur, and arcA, where fnr plays a predominant role. The multiple involvement of regulatory genes as well as co-regulation with antioxidant enzyme will enhance the efficiency of cellular growth and survival in the aerobic environment.

Telomerase is strongly activated in hepatocellular carcinoma but not in chronic hepatitis and cirrhosis

Telomerase is highly activated in human immortal cell lines and tumor tissues, whereas it is not activated in primary cell strains and many tumor-adjacent tissues. It is suggested that telomerase activation is one of the critical steps in malignant transformation. In the present study, the telomerase activity was investigated in hepatocellular carcinoma tissues and non-tumor liver tissues from Korean patients with chronic hepatitis and cirrhosis. Eighty two liver tissues (24 chronic hepatitis specimens, 34 cirrhosis specimens, and 24 hepatocellular carcinomas) were obtained from 23 chronic viral hepatitis patients, 19 cirrhosis patients (including 7 liver transplants), and 24 patients with hepatocellular carcinoma, of which the surrounding non-tumor liver tissues were available in 16 patients (1 chronic hepatitis and 15 cirrhosis). As negative controls, 3 normal liver tissues were included. Protein from liver specimens was purified by a detergent lysis method as described elsewhere, and telomerase activity was measured in 2 diluents of each sample (1:1 and 1:100) by a telomeric repeat amplification protocol (TRAP). Telomerase was strongly activated in 79% (19/24) of the hepatocellular carcinomas, while weakly in 8% (2/24) of the chronic hepatitis tissues and in 24% (8/34) of the cirrhosis tissues. All of 3 normal control livers showed no telomerase activation. No relationship could be observed between the enhancement of telomerase activity and tumor nature. None of the chronic heaptitis or cirrhosis patients with mild telomerase activation in the liver have developed hepatocellular carcinoma for at least 2 years of follow-up period. These results suggest that the strong enhancement of telomerase activity may be a critical part of hepatocarcinogenesis, although the exact mechanism of such high activation in hepatocellular carcinoma is not clear. In addition, further study will be necessary to clarify the reason why no telomerase activity detectable by a conventional TRAP can be seen in some hepatocellular carcinoma.

Cloning of the 52-kDa chitinase gene from Serratia marcescens KCTC2172 and its proteolytic cleavage into an active 35-kDa enzyme

A chitinase gene (pCHI52) encoding the 52-kDa chitinase was isolated from a Serratia marcescens KCTC2172 cosmid library. This chitinase gene consists of 2526 bp with an open reading frame that encodes 485 amino acids. Escherichia coli harboring the pCHI52 gene secreted not only a 52-kDa but also a 35-kDa chitinase into the culture supernatant. We purified both 52-kDa and 35-kDa chitinases using a chitin affinity column and Sephacryl-S-300 gel filtration chromatography. We determined that the 17 N-terminal amino acid sequences of the 52-kDa and the 35-kDa chitinase are identical. Furthermore, a protease obtained from S. marcescens KCTC2172 cleaved the 52-kDa chitinase into the 35-kDa protein with chitinase activity. These results suggest that the 35-kDa chitinase derives from the 52-kDa chitinase by post-translational proteolytic modification. The optimal reaction temperature of 45 degrees C and the optimal pH of 5.5 were identical for both enzymes. The specific activities of the 52-kDa and 35-kDa chitinases on natural swollen chitin were 67 mumol min-1 mg-1 and 60 mumol min-1 mg-1, respectively.

Doppler flow velocity waveforms of human fetal ductus arteriosus and branch pulmonary artery

Doppler waveforms of the human fetal ductus arteriosus and the branch pulmonary artery are distinct in their shape and might reflect fetal cardiovascular hemodynamics and vessel wall characteristics. The waveform of ductus arteriosus had two peaks, a higher one in systole and a lower one in diastole. Both peaks had slow acceleration and deceleration and looked like two narrow base isosceles triangles. This unique waveform might be due to vessel wall characteristics and an instantaneous pressure gradient between the main pulmonary artery and descending aorta. The waveform of the branch pulmonary artery showed very steep acceleration with the onset of ejection followed by steep decline, then low velocity flow during diastole. The characteristic shape of the branch pulmonary artery might be related to high vascular resistance, decreased capacitance and the earlier reflection wave of pulmonary vessels.

Detailed analysis of a 17q21 microdissection library by sequence bioinformatics and isolation of region-specific clones

A region-specific microdissection library originating from human chromosome 17q21, was constructed using the MboI linker-adaptor microcloning technique. DNA sequencing of 241 microclones resulted in the identification of 74 novel coding sequences, paralogs of known genes, and known, but previously unmapped, genes or expressed sequence tags that were "virtually" mapped to chromosome 17q21. By pooling the microclones as multiplexed hybridization probes, and by virtue of their origin on 17q21, we were able to identify approximately 150 P1 clones from the human Reference Library Data Base P1 Library that potentially map to chromosome 17q21. Verification of the 17q21 location of 16 P1 clones was accomplished by PCR analysis with STS primer pairs to known 17q21 genes or by FISH. Our results demonstrate the substantial advantage of combining the sequence analysis of microclones with multiplex hybridization strategies for gene discovery and mapping specific gene rich regions of the genome.

Evidence for symbiont-induced alteration of a host's gene expression: irreversible loss of SAM synthetase from Amoeba proteus

Symbiont-bearing xD amoebae no longer produce a 45-kDa cytoplasmic protein that functions as S-adenosylmethionine synthetase in symbiont-free D amoebae. The absence of the protein in xD amoebae is attributable to xD amoeba's failure to transcribe the corresponding gene as a result of harboring bacterial symbionts. However, xD amoebae have about half the level of enzyme activity found in D amoebae, indicating that they use an alternative source for the enzyme. xD amoebae originated from D amoebae by bacterial infection and now depend on their symbionts for survival. xD amoebae exhibit irreversible nucleolar abnormalities when their symbionts are removed, suggesting that X-bacteria supply the needed enzyme. A monoclonal antibody against the 45-kDa protein was produced and used as a probe in cloning its corresponding cDNA. The product of the cDNA was found to have S-adenosylmethionine synthetase activity. These results show how symbiotic X-bacteria may become essential cellular components of amoeba by supplementing a genetic defect for an amoeba's house-keeping gene that is brought about by an action of X-bacteria themselves. This is the first reported example in which symbionts alter the host's gene expression to block the production of an essential protein.

Effect of silkworm hemolymph on the expression of E. coli beta-galactosidase in insect cell lines infected with recombinant baculoviruses

The effects of silkworm hemolymph on the expression of foreign genes by recombinant baculoviruses in cell lines were studied. The expression efficiency of beta-galactosidase by recombinant virus containing the E. coli lacZ gene at various concentrations of hemolymph and FBS was determined in BmN and Sf cell lines. The addition of hemolymph to the medium containing FBS accelerated the expression of beta-galactosidase by recombinant viruses in both cells. It was more effective in BmN cells than in Sf cells. Hemolymph was most effective in enhancing virus multiplicity under conditions of 5% FBS.

Runt homology domain proteins in osteoblast differentiation: AML3/CBFA1 is a major component of a bone-specific complex

The AML/CBFA family of runt homology domain (rhd) transcription factors regulates expression of mammalian genes of the hematopoietic lineage. AML1, AML2 and AML3 are the three AML genes identified to date which influence myeloid cell growth and differentiation. Recently AML-related proteins were identified in an osteoblast-specific promoter binding complex that functionally modulates bone-restricted transcription of the osteocalcin gene. In the present study we demonstrate that in primary rat osteoblasts AML-3 is the AML family member present in the osteoblast-specific complex. Antibody specific for AML-3 completely supershifts this complex, in contrast to antibodies with specificity for AML-1 or AML-2, AML-3 is present as a single 5.4 kb transcript in bone tissues. To establish the functional involvement of AML factors in osteoblast differentiation, we pursued antisense strategies to alter expression of rhd genes. Treatment of osteoblast cultures with rhd antisense oligonucleotides significantly decreased three parameters which are linked to differentiation of normal diploid osteoblasts: the representation of alkaline phosphatase-positive cells, osteocalcin production, and the formation of mineralized nodules. Our findings indicate that AML-3 is a key transcription factor in bone cells and that the activity of rhd proteins is required for completion of osteoblast differentiation.

Isolation and characterization of the 54-kDa and 22-kDa chitinase genes of Serratia marcescens KCTC2172

A DNA fragment (pCHI5422) containing two genes encoding a 54-kD and a 22-kDa chitinase was isolated from a cosmid DNA library of Serratia marcescens KCTC2172. The complete nucleotide sequence of pCHI5422 consisting of 4581 bp was determined. The nucleotide sequence of the 22-kDa chitinase consists of 681 bp of open reading frame encoding 227 amino acids and is located 1422 bp downstream of the translation termination codon of the 54-kDa chitinase sequence. The 54-kDa chitinase gene consisted of 1497 bp in a single open reading frame encoding 499 amino acids. The genes encoding the 54-kDa and 22-kDa chitinase were separately subcloned in Escherichia coli and the individual chitinases were expressed and purified from the culture broth using chitin affinity chromatography. When chitohexaose was used as substrate, the major product of the enzymatic reaction of both the 54-kDa and 22-kDa chitinases was a (GlcNAc)2 dimer with a minor amount of monomer. The specific activity of the 54-kDa and 22-kDa chitinases were 300 microM (min)-1 mg-1 and 17 microM (min)-1 mg-1 on the natural swollen chitin, respectively.

GB virus C/hepatitis G virus infection among Korean patients with liver diseases and general population

GB virus C and hepatitis G virus (GBV-C/HGV) have been identified from the patients with acute or chronic liver diseases as possible agents of non-B, non-C hepatitis by two different groups, independently. To investigate whether GBV-C/HGV plays a role among Korean patients with liver diseases, GBV-C/HGV RNA were evaluated in 337 sera by the reverse transcription polymerase chain reaction (RT-PCR) using specific primers derived from 5'-noncoding region of GBV-C/HGV genome. GBV-C/HGV RNA was identified in 11/337 (3.3%). They consisted of 1/160 (0.6%) and 10/177 (3.3%) among the general population and patients with liver diseases, respectively (P < 0.01). Nucleotide sequences of all PCR amplicons were determined by the dideoxy chain termination method and analyzed by molecular evolutionary methods. The phylogenetic tree showed all sequences could be divided into three genotypes. These results indicate that: (1) GBV-C/HGV already exist in Korea; (2) GBV-C/HGV may play some role as an etiologic factor among the Korean patients with liver diseases; (3) GBV-C/HGV infection is rare among Korean general population; and (4) there are at least three different types of GBV-C/HGV in Korea.

A novel 90-kDa stress protein induced in fish cells by fish rhabdovirus infection

A 90 kDa cellular protein in a fish cell, CHSE-214, showed increased expression by the infection of infectious hematopoietic necrosis virus (IHNV), heat shock, 2-mercaptoethanol, copper sulfate, and cadmium sulfate, and was detected in various kinds of cells such as human, rat, and mouse cells. The molecular mass of the 90 kDa protein was different from those of the hsp90 and grp94. In addition, all the anti-stress protein MAbs did not react with the 90 kDa protein. Finally, the subcellular distribution of the 90 kDa protein, determined by Western blots of subcellular fractions, was found to be mainly nuclear, both in normal and IHNV-infected CHSE-214 cells. The present results indicate that the 90 kDa protein is a kind of stress protein. However, based on its molecular mass, antigenic characteristics, and subcellular distribution, it is likely that this protein is a novel stress protein that has not been previously described in animal systems, especially in fish systems.

Differential activation of NAD kinase by plant calmodulin isoforms. The critical role of domain I

NAD kinase is a Ca2+/calmodulin (CaM)-dependent enzyme capable of converting cellular NAD to NADP. The enzyme purified from pea seedlings can be activated by highly conserved soybean CaM, SCaM-1, but not by the divergent soybean CaM isoform, SCaM-4 (Lee, S. H., Kim, J. C., Lee, M. S., Heo, W. D., Seo, H. Y., Yoon, H. W., Hong, J. C., Lee, S. Y., Bahk, J. D., Hwang, I., and Cho, M. J. (1995) J. Biol. Chem. 270, 21806-21812). To determine which domains were responsible for this differential activation of NAD kinase, a series of chimeric SCaMs were generated by exchanging functional domains between SCaM-4 and SCaM-1. SCaM-4111, a chimeric SCaM-1 that contains the first domain of SCaM-4, was severely impaired (only 40% of maximal) in its ability to activate NAD kinase. SCaM-1444, a chimeric SCaM-4 that contains the first domain of SCaM-1 exhibited nearly full ( approximately 70%) activation of NAD kinase. Only chimeras containing domain I of SCaM-1 produced greater than half-maximal activation of NAD kinase. To define the amino acid residue(s) in domain I that were responsible for this differential activation, seven single residue substitution mutants of SCaM-1 were generated and tested for NAD kinase activation. Among these mutants, only K30E and G40D showed greatly reduced NAD kinase activation. Also a double residue substitution mutant, K30E/G40D, containing these two mutations in combination was severely impaired in its NAD kinase-activating potential, reaching only 20% of maximal activation. Furthermore, a triple mutation, K30E/M36I/G40D, completely abolished NAD kinase activation. Thus, our data suggest that domain I of CaM plays a key role in the differential activation of NAD kinase exhibited by SCaM-1 and SCaM-4. Further, the residues Lys30 and Glu40 of SCaM-1 are critical for this function.

Induction of oh8Gua glycosylase in rat kidneys by potassium bromate (KBrO3), a renal oxidative carcinogen

It has been suggested that 8-hydroxyguanine (oh8Gua), a DNA adduct formed by active oxygens, impairs the maintenance of genetic integrity, oh8Gua glycosylase removes oh8Gua residues as a free base from DNA strands. In E. coli, it has been demonstrated that oh8Gua glycosylase is induced in response to oxidative stress, but the oxidative inducibility in mammalian tissues has not yet been studied. In the present study, the inducibility of oh8Gua glycosylase was tested by comparing activity changes of this enzyme in the kidney and the liver of rats treated with potassium bromate (KBrO3). KBrO3 is known to cause oxidative damage to the kidney but not to other organs. With a single dose of KBrO3 (80 mg/kg, i.p.), activity in the kidney was found to increase significantly at 3 h compared to that at zero time. At 6 h, activity peaked, showing a 6-fold increase over that at zero time. Thereafter, it decreased and returned to its zero time level at 12 h. With increasing doses of KBrO3 (up to 160 mg/kg, i.p.), activity increased linearly with increased dosage, and over 40 mg/kg, i.p., activity increased to a level significantly higher than that in the control. In contrast to the time- and dose-dependent changes in activity in the kidney, no significant change was observed in the liver under the same conditions as above. These results show that oh8Gua glycosylase is also induced oxidatively in mammalian tissues. The induction in this tissue as well as in E. coli indicates that the adaptive response of this enzyme to oxidative stress is a general phenomenon in aerobic organisms and implies that the repair of oh8Gua residues in DNA is a process important for the survival of organisms in an aerobic environment.

The organization of acromiodeltoid and spinodeltoid motor nuclei in rat spinal cord

The retrograde intraaxonal transport of fluorescent dyes (10% Bisbenzimide or 2% Nuclear Yellow) was used to identify the motoneuron populations that control two prime movers of the rat shoulder joint, the acromiodeltoid (Ad) and spinodeltoid (Sd) muscles. The Ad and Sd motor nuclei were both comprised of an average 30-40 motoneurons distributed between spinal segments C5 and C7, in lateral regions of Rexed's lamina IX. Although there was considerable overlap among them, the center of the Ad motor nucleus was consistently located more rostral and medial than that for the Sd motor nucleus.

Okadaic acid increases fibronectin synthesis in MC3T3-E1 cells

Okadaic acid, a potent specific inhibitor of serine/threonine protein phosphatases type 1 and 2A, affects several gene expressions in various cells. To determine whether okadaic acid affects the expression of fibronectin in MC3T3-E1 cells, we measured mRNA level and synthesis of fibronectin by Northern blot hybridization and immunoprecipitation methods, respectively. Okadaic acid (10-50 ng/ml) increased both mRNA level and synthesis of fibronectin in a dose-dependent manner. The increase of fibronectin mRNA by okadaic acid was strongly attenuated by the inhibition of new protein synthesis. The results indicate that okadaic acid, inhibitor of protein phosphatases, increases fibronectin synthesis in MC3T3-E1 cells.

Stimulation of fibronectin synthesis through the protein kinase C signalling pathway in normal and transformed human lung fibroblasts

We examined the role of the protein kinase C (PKC) signaling pathway in the stimulation of fibronectin synthesis in both normal and transformed human lung fibroblasts. Phorbol myristate acetate (PMA), a potent PKC activator, stimulated fibronectin synthesis in both normal and transformed fibroblasts in a time and dose dependent fashion. Down-regulation of PKC by prior exposure of cells to a high concentration of PMA blocked the increase in fibronectin synthesis and mRNA levels induced by PMA. Bisindolylmaleimide, a specific inhibitor of PKC, also abolished the PMA-induced fibronectin synthesis. 4 alpha-phorbol didecanoate, an inactive phorbol ester, failed to affect fibronectin synthesis. These data suggest that PMA stimulates fibronectin synthesis and gene expression through the PKC signaling pathway in both normal and transformed human lung fibroblasts.

Expression patterns of bone-related proteins during osteoblastic differentiation in MC3T3-E1 cells

Bone formation involves several tightly regulated gene expression patterns of bone-related proteins. To determine the expression patterns of bone-related proteins during the MC3T3-E1 osteoblast-like cell differentiation, we used Northern blotting, enzymatic assay, and histochemistry. We found that the expression patterns of bone-related proteins were regulated in a temporal manner during the successive developmental stages including proliferation (days 4-10), bone matrix formation/maturation (days 10-16), and mineralization stages (days 16-30). During the proliferation period (days 4-10), the expression of cell-cycle related genes such as histone H3 and H4, and ribosomal protein S6 was high. During the bone matrix formation/maturation period (days 10-16), type I collagen expression and biosynthesis, fibronectin, TGF-beta 1 and osteonectin expressions were high and maximal around day 16. During this maturation period, we found that the expression patterns of bone matrix proteins were two types: one is the expression pattern of type I collagen and TGF-beta 1, which was higher in the maturation period than that in both the proliferation and mineralization periods. The other is the expression pattern of fibronectin and osteonectin, which was higher in the maturation and mineralization periods than in the proliferation period. Alkaline phosphatase activity was high during the early matrix formation/maturation period (day 10) and was followed by a decrease to a level still significantly above the baseline level seen at day 4. During the mineralization period (days 16-30), the number of nodules and the expression of osteocalcin were high. Osteocalcin gene expression was increased up to 28 days. Our results show that the expression patterns of bone-related proteins are temporally regulated during the MC3T3-E1 cell differentiation and their regulations are unique compared with other systems. Thus, this cell line provides a useful in vitro system to study the developmental regulation of bone-related proteins in relation to the different stages during the osteoblast differentiation.

Regulatory elements that control transcription activation and unsaturated fatty acid-mediated repression of the Saccharomyces cerevisiae OLE1 gene

In Saccharomyces cerevisiae, unsaturated fatty acids are formed from saturated acyl-CoA precursors by Ole1p, a delta-9 fatty acid desaturase. OLE1 mRNA levels are differentially regulated by the addition of saturated or unsaturated fatty acids to the growth medium. One component of this regulation system involves the control of OLE1 transcription. Saturated fatty acids induce a 1.6-fold increase in transcription activity, whereas a large family of unsaturated fatty acids repress OLE1 transcription as much as 60-fold. A deletion analysis of OLE1 promoter::lacZ fusion reporter genes identified a 111-base pair (bp) fatty acid-regulated (FAR) region approximately 580 bp upstream of the start codon that is essential for transcription activation and unsaturated fatty acid repression. Deletion of an 88-bp sequence within that region resulted in a complete loss in transcription activation and unsaturated fatty acid regulation. The 111-bp FAR element strongly activates transcription and confers unsaturated fatty acid regulation on a heterologous CYC1 promoter test plasmid. Essential elements required for unsaturated fatty acid repression of OLE1 were found in the 5 and 3 region of the 111-bp sequence. The FAR element-mediated activation and fatty acid repression of transcription was found to be closely tied to fatty acyl-CoA metabolism. Two fatty acid activation genes, FAA1 and FAA4, were found to be essential for unsaturated fatty acid repression of OLE1 through the FAR sequences. Disruption of either gene results in reduced levels of unsaturated fatty acid repression; disruption of both genes completely blocks the regulatory response. Acyl-CoA binding protein (ACBP) plays a role in determining the level of FAR element activated transcription. Disruption of the ACBP gene causes a >5-fold activation of OLE1 transcription and a similar increase in OLE1 mRNA levels. Unsaturated fatty acid repression of OLE1 transcription, however, is not affected by the disrupted ACBP gene. These studies show that promoter elements responsible for unsaturated fatty acid-mediated transcription repression are tightly linked to OLE1 activation sequences and that OLE1 transcription levels are closely tied to acyl-CoA metabolism.

A constructive approach for nonlinear system identification using multilayer perceptrons

This paper combines a conventional method of multivariable system identification with a dynamic multi-layer perceptron (MLP) to achieve a constructive method of nonlinear system identification. The class of nonlinear systems is assumed to operate nominally around an equilibrium point in the neighborhood of which a linearized model exists to represent the system, although normal operation is not limited to the linear region. The result is an accurate discrete-time nonlinear model, extended from a MIMO linear model, which captures the nonlinear behavior of the system.

Okadaic acid inhibits alkaline phosphatase activity in MC3T3-E1 cells

Alkaline phosphatase activity is regulated by various hormones and growth factors at least in part through the phosphorylation of target proteins during the bone cell differentiation. To investigate the role of protein phosphorylation in alkaline phosphatase activity in MC3T3-E1 osteoblast, we used okadaic acid which is a potent specific inhibitor of serine/threonine protein phosphatases to type 1 and 2A. Alkaline phosphatase activity in cellular layer was measured by spectrophotometer using p-nitrophenyl phosphate as substrate and data were expressed as p-nitrophenyl of nmol/min/mg of protein. Okadaic acid (1-50 ng/ml) caused the inhibition of alkaline phosphatase activity in MC3TC-E1 cells. At 50 ng/ml of okadaic acid showed the maximal inhibitory effect on alkaline phosphatase activity. Okadaic acid (50 ng/ml) also inhibited alkaline phosphatase activity in all differentiation stages. These results indicate that okadaic acid inhibits alkaline phosphatase activity in MC3T3-E1 cells.

Ventricular tachycardia and exercise related syncope in children with structurally normal hearts: emphasis on repolarisation abnormality

OBJECTIVE

To emphasize the importance of ventricular tachycardia associated with repolarisation abnormality in syncope associated with exercise.

DESIGN

Retrospective analysis of data on children presenting with syncope between 1985 and 1993.

PATIENTS

5 apparently normal children with recurrent exercise related syncope associated with electrocardiographically abnormal TU complexes.

RESULTS

3 children were diagnosed as having an intermediate form of the long QT syndrome and catecholamine sensitive ventricular tachycardia because the abnormal TU complexes were associated with polymorphic ventricular tachycardia that was not typical of torsades de pointes. Tachycardia was induced by exercise in all patients and by isoprenaline in the one patient who was tested. One patient also had sinus node dysfunction. One child had incessant salvos of polymorphic ventricular arrhythmias and intermittent abnormal TU complexes suggestive of repolarisation abnormalities. The other had typical congenital long QT syndrome. Treatment was effective in three patients; two patients took a beta blocker alone and one took a beta blocker and low doses of amiodarone. One patient died suddenly, death being associated with sinus node dysfunction. In one patient with incessant ventricular arrhythmias treatment with a beta blocker, amiodarone, or Ic drugs was ineffective and always associated with proarrhythmia or syncope. He was not given further treatment and was asymptomatic despite having mild cardiomegaly.

CONCLUSIONS

Ventricular tachycardia associated with repolarisation abnormality was an important cause of exercise related syncope in apparently normal children. TU complex abnormalities can be identified by repeated electrocardiography. beta Blockers are effective in preventing recurrent episodes. The role of amiodarone in this type of ventricular tachycardia needs further evaluation.

Five cases of cytomegalovirus infection detected by in situ hybridization and antigenemia assay

We report five cases of cytomegalovirus infection in immunocompromised patients which were detected by either cytomegalovirus antigenemia assay or in situ hybridization. Four cases had leukemia and the other had chronic renal failure. All the three BMT recipients suffered from GvHD. Interestingly, there was an unique case of CMV disease without a history of BMT, which reminded us that CMV could attack immunocompromised patients who had not undergone transplantation, too. Four out of five cases died. We think that cytomegalovirus infection or disease should not be regarded as a minor problem in post-transplantation infection in Korea.

Echocardiographic evaluation of hearts with twisted atrioventricular connections (criss-cross heart)

An echocardiographic study was performed on seven patients with twisted atrioventricular connections (criss-cross heart) relative to the usual atrial arrangement. The atrioventricular connections were concordant in five patients and discordant in two. The ventriculoarterial junction was either double-outlet right ventricle (n = 6) or discordant connections (n = 1). Associated cardiac defects were ventricular septal defect (n = 7), pulmonary stenosis (n = 5), straddling tricuspid valve (n = 2), and straddling mitral valve (n = 1). Malalignment between the atrial and ventricular septum was the most important feature of this disease and resulted in altered spatial orientation of the trabecular ventricular septum, and recesses in the ventricles and the right atrium. When assessed by echocardiography, these anatomical features were not invariably recognized in every case, but they were dependent upon the type of atrioventricular connections and the presence of straddling of the atrioventricular valves. Left ventricular recess was the most consistent feature and was present in every patient, regardless of the atrioventricular connections. Right atrial recess was found in four of five patients with concordant atrioventricular connections but was not present in patients with discordant atrioventricular connections. Right ventricular recess was recognized as such in a single patient with concordant atrioventricular connection and straddling mitral valve. The trabecular septum was oriented in a horizontal plane in hearts with concordant atrioventricular connections and without atrioventricular valve straddling. The trabecular septum was oriented semivertically in all other hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional demonstration and endoscopic treatment of pancreaticoperitoneal fistula

An alcoholic man presented with bloody ascites, which was confirmed as pancreatic ascites complicating chronic pancreatitis. Endoscopic retrograde pancreatography [ERP] demonstrated a ductal disruption at the head of the pancreas, a fistulous tract, and extravasation to the peritoneal cavity. Furthermore, a computerized tomographic scan subsequent to the endoscopic retrograde pancreatography (ERP-CT scan) gave the three-dimensional anatomy of the fistulous tract by the residual contrast media in the pancreatic duct and the fistulous tract. The pancreatic ascites, which was refractory to conventional medical treatment of a 5-wk duration, was successfully treated by endoscopic placement of a pancreatic stent and administration of a somatostatin analogue.

Hydronephrosis secondary to congenital pelvic arteriovenous malformation: a case report

We report on a 26-year-old woman with a pelvic mass that caused ureteral obstruction and a hydronephrotic kidney. Diagnosis was congenital pelvic arteriovenous malformation and surgery was successful. The patient underwent staged preoperative intra-arterial embolization to decrease operative morbidity and facilitate complete removal.

Takayasu arteritis in Korean children: Clinical report of seventy cases

Seventy cases of Takayasu arteritis in Korean children are reported. There were 57 females and 13 males (male-to-female ratio; 1:4.4). The youngest patient was a 3-year-old female. Family history was positive in one patient. The most common chief complaints on admission were dyspnea, headache, palpitation, and edema which were due to hypertension and congestive heart failure. Hypertension was seen in 65 out of 70 patients (92.8%). The abdominal aorta, thoracic aorta, and renal arteries were the most commonly involved sites in these children. Two patients had nephrotic syndrome. The frequency of positive tuberculin reaction was much higher in children with Takayasu arteritis compared with the general population, and the intensity of the reaction was also stronger. The majority of the patients required immediate medical treatment to control congestive heart failure due to hypertension at initial presentation. When ESR was elevated, corticosteroid was administered. Surgical treatment showed good results in six out of ten cases. Percutaneous intraluminal angioplasty was effective for lowering the blood pressure in six out of nine cases. In three cases, restenosis occurred and angioplasty was repeated in two cases.

Pulmonary veins in total anomalous pulmonary venous connection with obstruction: demonstration using silicone rubber casts

We studied the postmortem vascular anatomy of four patients with total anomalous pulmonary venous connection (TAPVC) with obstruction using a silicone rubber casting method. Two patients were studied clinically but died before therapeutic intervention, one died after corrective surgery, and another was not diagnosed before death. The morphologic types were supracardiac (2), infracardiac (1), and mixed (1). One of the supracardiac forms had a stenosis at the left vertical vein by a bronchoarterial vise, and a collateral channel to the right superior caval vein was also present. In the other supracardiac case, a left upper pulmonary vein was connected to the left vertical vein above the stenotic portion, resulting in postoperative pulmonary hemorrhage into the left upper lobe. The patient with infracardiac TAPVC had a tree-shaped descending vertical vein and small opening at the inferior caval vein. In the mixed type, a right upper pulmonary vein ran between the pulmonary artery and bronchus draining into the superior caval vein, and the rest of the drainage was to the portal vein.

Homologous fibronectin enhances healing of excised wounds in rats

In order to evaluate the effects of a topical application of homologous fibronectin on the healing of skin wounds, we made 2 excisional wounds on the back skin of each rat, applied ointment with or without fibronectin purified from citrated homologous plasma, and evaluated the effect according to wound size and microscopic findings. Excised lesions treated with carrier alone, but the difference was significant only in the early phase of wound healing, 2 and 3 days, according to wound size and microscopic changes. A significant decrease in wound size could be found in both groups, treated with ointment containing and not containing fibronectin, between day 4 and 9 when wound contraction was a major contributor to wound closure. Therefore it can be concluded that topical application of fibronectin has a beneficial effect on wound healing during its early phase, but no significant influence on wound contraction.

Fixed subaortic stenosis: anatomical spectrum and nature of progression

Retrospective echocardiographic review identified 58 consecutive infants and children with fixed subaortic stenosis. Mean (SD) age at diagnosis was 4.8 (3.6) years (range two days to 14.7 years), and diagnosis occurred in infancy in eight. Associated cardiac abnormalities were present in 41 (71%) whereas fixed subaortic stenosis was an isolated lesion in 17 (29%). Four types of fixed subaortic stenosis were identified: short segment (47 (81%)), long segment (7 (12%)), posterior displacement of the infundibular septum with additional discrete narrowing of the left ventricular outflow tract (3 (5%)), and redundant tissue arising from the membranous septum (1 (2%)). Echocardiographic studies had been performed before the diagnosis of fixed subaortic stenosis in nine patients, all with associated abnormalities. These were performed in infancy in each and showed a "normal" left ventricular outflow tract in six and posterior deviation of the infundibular septum in three. In 16 patients serial echocardiographic studies had been performed after the diagnosis of fixed subaortic stenosis but before surgery of the left ventricular outflow tract. Rapid evolution of short segment to long segment narrowing was seen in one patient, and tethering of the aortic valve or mitral valve developed in a further four patients. Aortic valve or mitral valve involvement was not seen before the age of three years but was common thereafter (10/40 patients, 25%). Fixed subaortic stenosis may be an "acquired" lesion with the potential for changes in form as well as progression in severity of left ventricular outflow tract obstruction.

Study on Doppler waveforms from the fetal cardiovascular system

In order to see whether Doppler parameters from the fetal cardiovascular system change with fetal growth and to compare Doppler values from the various sites, a total of 274 Doppler studies on 73 human fetuses were analyzed. With advancing gestation, the heart rate decreased, the diastolic filling period of both atrioventricular valves increased, and the systolic ejection time of both semilunar valves remained unchanged. Most of the Doppler parameters from the 4 cardiac valves, the aortic arch, the branch pulmonary artery, and the ductus arteriosus increased with increasing gestation. Doppler waveforms from the branch pulmonary artery, the ductus arteriosus, and the aortic arch each had a distinct shape. More study is needed to define the exact relationship between the gestation period and the Doppler parameters and to determine whether Doppler parameters will be useful in assessing fetal heart function.

Anomalous subaortic position of the brachiocephalic vein (innominate vein): an echocardiographic study

In 24 (0.98%) of 2457 patients with congenital heart disease the brachiocephalic vein was in an anomalous position below the aortic arch. This is a much higher proportion of such cases than reported so far. This high frequency may arise from differences in the study population and the method of diagnosis. This venous anomaly was more common in patients with tetralogy of Fallot or ventricular septal defect with pulmonary atresia. Patients with the venous anomaly were more likely to have a right aortic arch. The anomalous course of the brachiocephalic vein from the neck to the junction of the superior vena cava was shown by cross sectional echocardiography. In doubtful cases, Doppler study usually clarified the anatomical arrangement.

Absent right superior caval vein (vena cava) with normal atrial arrangement

Eight cases of absent right superior caval vein (vena cava) with normal atrial arrangement from the Great Ormond Street database were reviewed. In each case the right subclavian vein and jugular vein drained into a persistent left superior caval vein through a bridging vein. In six cases the left superior caval vein drained into the right atrium by way of the coronary sinus, and in two cases it drained into the left atrium directly because of the complete unroofing of the coronary sinus. The frontal plane P wave axis was displaced leftwards and upwards in four out of seven cases in which an electrocardiogram was available. No case showed arrhythmia on a standard electrocardiogram preoperatively. Echocardiograms were available in four cases and in each case diagnosis of the anomalous connections of the systemic vein was possible. Only one third of the cases showed a crescentic shadow of the persistent left superior caval vein on chest x ray. A chest x ray and electrocardiogram do not provide the means of reliable diagnosis of this condition, though they may suggest the possibility of its existence. Definitive diagnosis requires cross sectional echocardiography or angiocardiography or both.