Serologic responses of Korean soldiers serving in malaria-endemic areas during a recent outbreak of Plasmodium vivax

Anti-Pv200 antibody levels were assessed in samples from endemic areas of Plasmodium vivax malaria in the Republic of Korea (ROK), using an indirect enzyme-linked immunosorbent assay (ELISA) method. Asymptomatic carriers of P. vivax were detected using nested polymerase chain reaction (PCR) of blood samples. Anti-Pv200 antibody levels in 20 vivax malaria patients (optical density +/- standard deviation [OD +/- SD] values 1.85 +/- 0.29 of IgG isotype and 1.33 +/- 1.33 of IgM isotype) were markedly higher than those of uninfected, malaria-naive controls (0.08 +/- 0.16 of IgG isotype and 0.04 +/- 0.04 of IgM isotype). Antibody levels for 7 out of 8 soldiers with a recent malaria infection were sustained above the cut-off values for 4 months after successful treatment. Analysis of serum collected from 40 healthy, asymptomatic soldiers who had a P. vivax malaria attack within 3 months after our sampling, revealed 11 antibody-positive samples (27.5%), compared to 5 positive samples (12.5%) collected from a random selection of 40 soldiers. Among a larger pool of 1,713 soldiers who had served in high-risk areas for P. vivax transmission, 15% were antibody positive. Among 1,000 blood samples from asymptomatic soldiers who had served in the high-risk areas, 4 samples (0.4%) were parasite positive, as determined by nested PCR. Our results show that anti-Pv200 antibody levels can provide useful information in the late diagnosis of P. vivax malaria infection in a previously naive population and also in large seroepidemiologic studies. Furthermore, our results suggest that asymptomatic P. vivax carriers could be important in the current outbreak of malaria in Korea.

Mitochondrial ATPase 6 gene expression in unfertilized oocytes and cleavage-stage embryos

OBJECTIVE

To compare the level of mitochondrial ATPase 6 gene expression in unfertilized oocytes and cleavage-stage embryos.

DESIGN

Reverse transcription polymerase chain reaction was performed in unfertilized oocytes and cleavage-stage embryos derived from tripronucleate embryos to determine ATPase 6 gene expression.

SETTING

Department of Obstetrics and Gynecology, Human Genetics Laboratory, Infertility Medical Center of CHA General Hospital, College of Medicine, Pochon CHA University, Seoul, Korea.

PATIENT(S)

Oocytes were obtained from infertile couples undergoing in vitro fertilization.

INTERVENTION(S)

Unfertilized oocytes collected at 48 hours after retrieval and cleavage-stage embryos derived from tripronucleate embryos were prepared for evaluation of mitochondrial gene expression.

MAIN OUTCOME MEASURE(S)

Comparison of ATPase 6 gene expression by using single-cell reverse transcription polymerase chain reaction.

RESULT(S)

Expression of unfertilized oocytes decreased compared with early cleavage-stage embryos.

CONCLUSION(S)

Our findings of decreased ATPase 6 expression in unfertilized oocytes suggest that there may be a decrease in the mitochondrial functional capacity of oxidative phosphorylation.

The short-term changes of bone mineral metabolism following bone marrow transplantation

Organ transplantation is now the treatment of choice for many patients with life-threatening chronic diseases. A new set of side effects unique to these groups of patients has become recognized, and bone disease is one of these complications. However, little is known about the effects of myeloablative treatment followed by bone marrow transplantation (BMT) on bone mineral metabolism. We have prospectively investigated 31 patients undergoing BMT for hematologic diseases. Serum concentrations of calcium, phosphorus, creatinine, gonadotropins, sex hormones, and the biochemical markers of bone turnover were measured. The samples were collected before BMT and 1, 2, 3, 4, and 12 weeks, 6 months, and 1 year after BMT. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry before BMT and 1 year after BMT. The serum carboxy-terminal cross-linked telopeptide of type I collagen increased progressively until 4 weeks after BMT. Thereafter, it began to decrease and reached basal values after 1 year. Serum osteocalcin decreased progressively until 3 weeks after BMT. After that, it increased and reached basal values after 3 months. No distinct differences were observed in the serum biochemical turnover markers between males and females, or between patients who received total body irradiation and those who did not. One year after BMT, lumbar spine BMD had decreased by 2.2%, and total proximal femoral BMD had decreased by 6.2%. Eighty-six percent of the women (12/14) went into a menopausal state immediately after BMT. This was caused by high gonadotropin levels and low estradiol levels. In contrast, gonadotropin levels and testosterone levels did not change significantly in the male patients after BMT. In conclusion, the rapid impairment of bone formation and the increase in bone resorption, as shown by the biochemical markers in this study, might play a role in post-BMT bone loss.

Neural control of the compensatory increase of testosterone in hemicastrated adult male rats

It is unclear why the concentration of testosterone increases in the testicular vein after hemicastration without corresponding alteration in gonadotropins. The present work was undertaken to examine whether the testosterone levels could be modified by denervation of the testis in adult rats. Both systemic and testicular blood samples were collected either immediately before or 6 and 24 hours after hemicastration from the rats two weeks after denervation of either inferior spermatic nerves (ISN) or ISN plus superior spermatic nerves (ISN-SSN). Increase of testicular testosterone induced by hemicastration was significantly (P<0.05) inhibited in these rats, as compared with the sham animals (at 6 and 24 hours, ISN vs sham: 16.00+/-3.35 vs 42.72+/-13.85 and 26.93+/-8.68 vs 71.16+/-13.30 whilst ISN-SSN vs sham: 31.63+/-7.92 vs 60.61+/-18.11 and 27.70+/-8.93 vs 93.92+/-19.73 ng/ml, respectively), whereas no significant change in LH was observed in all the experimental groups. FSH underwent no alteration in all the ISN denervation groups, but a significant elevation was observed in the ISN-SSN denervation groups (P<0.05) before hemicastration. Therefore, it appears that the change in FSH is not the cause of the inhibition of testosterone increase in the hemicastrated rats after testicular denervation and that ISN plays an active role in regulation of testosterone increase induced by hemicastration.

Language supports for children's understanding of numerical fractions: cross-national comparisons

This study examined Croatian, Korean, and U.S. children's knowledge of numerical fractions prior to school instruction. The research is part of an ongoing project examining the influence of language characteristics on mathematical thinking and performance. The part-whole quantitative relation denoted by numerical fractions may be easier to understand in East Asian languages like Korean. In these languages, the concept of fractional parts is embedded in the mathematics terms used for fractions. The results from this study suggest that the Korean vocabulary of fractions may influence the meaning 6- to 7-year-old children ascribe to numerical fractions and that this results in children being able to associate numerical fractions with corresponding pictorial representations prior to formal instruction.

[A novel chiral selector in capillary electrophoresis--beta-cyclodextrin polymer]

Three chiral selectors CM-beta-CD, EP-beta-CD, beta-CD were studied for the enatio-separation of three drugs under optimum conditions respectively. The results demonstrate that the resolving power for the drugs is as follows CM-beta-CD > EP-beta-CD > beta-CD, with the exception of lobeline. This is due to the--CH2COOCH3 group of CM-beta-CD, which will change the combination and improve the recognition on guest molecules. Although EP-beta-CD is inferior to CM-beta-CD for the separation of chlorpheniramine and verapamil, it has excellent recognition on lobeline and it has not been reported previously. In most cases EP-beta-CD is superior to beta-CD. The explanations are: (1) EP-beta-CD has good solubility in water, which enables high concentrations to be used and consequently achieves excellant separation of racemic compounds, (2) the polymerization of beta-CD changes the properties of CD units and the process produces a more rigid and different conformation from CD, (3) we must attribute much merits to the cooperation or synergism of two, three or even more CD moieties of two polymers for inclusion. Complexation with analytes possesses more than one guest part in their structure.

Enhanced hepatocyte uptake and liver targeting of methotrexate using galactosylated albumin as a carrier

Liver targeting of drugs has wide therapeutic implications due to numerous liver-related diseases. Using conjugates of methotrexate (MTX) to variously galactosylated bovine serum albumin (BSA), we studied whether we could enhance the liver targeting of MTX, a model drug, via galactose receptors selectively abundant on the hepatocytes. Here, we report that the galactosylation of the carrier protein BSA significantly enhanced the hepatocyte uptake and liver targetability of MTX. In vitro, the amount of MTX taken up by rat hepatocytes was positively correlated with the galactose content in BSA. MTX conjugates were relatively stable in plasma, but released MTX with time in liver homogenates. These results imply that the conjugates would exert low toxicity in the blood, but have therapeutic activity in the liver by liberating MTX. In vivo, MTX-galactosylated BSA conjugates (MTX-L(24)BSA) showed significantly different pharmacokinetics from free MTX or MTX-BSA conjugates. The plasma level of free MTX rapidly declined in a biexponential fashion with an apparent terminal half-life of 0.35 h. MTX-BSA conjugates showed the slowest decline with an apparent terminal half-life of 6 h, whereas MTX-L(24)BSA showed a biphasic pattern; a rapid distributive phase with a half-life of 0.567 h and a slow terminal phase. MTX-L(24)BSA showed the highest liver targetability, when evaluated in terms of two indices based on the area under the total amount of radioactivity-time curve (AUQ); Te*(liver), % AUQ(liver) to total AUQ, and te*, the ratio of AUQ(liver) to AUQ(kidney). Compared with free MTX and MTX-BSA, MTX-L(24)BSA showed about twofold higher Te*(liver) of 87.5%. The te* of MTX-L(24)BSA was 25- and fourfold higher than those of free MTX and MTX-BSA, respectively. Moreover, MTX-L(24)BSA showed a gradual increase in the therapeutically active intact form of MTX in the liver while showing the lowest level of intact MTX in the kidney. These results suggest that galactosylated BSA has a great potential as an hepatocyte-directed and more effective liver targeting carrier of drugs for liver diseases.

A case of primary transitional cell carcinoma of the fallopian tube

The primary carcinoma of the fallopian tube is the rarest of all gynecologic malignancies and histologically most of them are adenocarcinomas. Primary transitional cell carcinomas are extremely rare in the fallopian tube. A 63-year-old postmenopausal woman presenting with lower abdominal pain was found to have a left adnexal mass. Exploratory laparotomy revealed a mass arising from the fallopian tube with the histologic features of transitional cell carcinoma. Light and electron microscopic studies supported the notion of transitional cell carcinoma. The tumor was extended to the muscle layer and confined to the left fallopian tube without metastasis. The patient received 3 courses of systemic cisplatin-based chemotherapy and has been well with no evidence of recurrence until August, 1998.

Co-administration of toluene and xylene antagonized the testicular toxicity but not the hematopoietic toxicity caused by ethylene glycol monoethyl ether in Sprague-Dawley rats

Occupational painters are exposed to ethylene glycol monoethyl ether (EGEE), a widely used emulsifying solvent known to cause testicular degeneration and bone marrow depression, together with toluene (TOL) and xylene (XYL) as a mixture. In the previous study (Chung et al., Tox. Lett. 104:143, 1999), testicular atrophy caused by EGEE (200 mg/kg) was shown to be antagonized by co-administration of TOL (250 mg/kg) and XYL (500 mg/kg). This study was conducted to provide histological support for the previously observed antagonistic protective effect of TOL + XYL on EGEE inducible testicular toxicity and to determine whether a similar antagonistic effect can be demonstrated against the EGEE derived hematopoietic toxicity. Compared to the extent of seminiferous tubule degeneration caused by EGEE (150 mg/kg, six times per week for 4 weeks), testes of rats given co-administration of TOL (250 mg/kg) + XYL (500 mg/kg) showed dramatically reduced tubular degeneration. Hyperplasia of Leydig cells in the interstitium was observed in both EGEE and EGEE + TOL + XYL-treated rats. Although a minimal dose of EGEE causing testicular atrophy was used, WBC and platelet counts were decreased significantly. In the TOL + XYL-treated control group, the WBC and platelet counts were not decreased. However, the bone marrow depression caused by EGEE was not reversed by the combined administration of TOL + XYL. In all experimental groups (EGEE alone, TOL + XYL, EGEE + TOL + XYL), plasma levels of creatinine and alkaline phosphatase were significantly decreased. In addition to the marked testicular atrophy, EGEE also decreased the weights of adrenal glands and epididymis. In conclusion, while the testicular degeneration caused by EGEE was antagonized by TOL + XYL, the EGEE derived hematopoietic suppression was not reversed.

[Vasoactive intestinal polypeptide induced prolactin release is model dependent in free-moving rats]

Our previous experiments in vitro showed that the stimulating effects of vasoactive intestinal polypeptide (VIP) on pituitary (PRL) depended on the endocrinal status of the animals. The present investigation was to determine whether the effect of VIP varied in vivo with changes of different physiological conditions. For infusion of VIP (5 micrograms/100 g body weight) and collection of blood sample, all the animals were cannulated with silicon tube into jugular vein 2-3 d before the experiments. The results showed that VIP concentration in blood was increased rapidly after the infusion (maximum: 21.32 +/- 2.33 ng/ml at 10 min and lasting more than 30 min). The concentration of PRL in blood of all the animals tested was increased significantly (P < 0.05) after VIP infusion. The increase rate of PRL induced by VIP was higher in male rats (158.04 +/- 37.06), but lower in the female (Diestrus: 50.42 +/- 16.44, Proestrus: 62.67 +/- 21.34) and in Suckling-depended lactating ones (Suckled 90.00 +/- 36.00 vs. Separated 31.05 +/- 4.42). The above observations suggest that the VIP action in vivo depends on the endocrinal and/or neural status of the animals.

A case of Strongyloides stercoralis infection

Strongyloidiasis has been recognized as one of the life-threatening parasitic infections in the immunocompromised patients. We report an intestinal infection case of Strongyloides stercoralis in a 61-year-old man. Rhabditiform larvae were detected in the stool examination and developed to filariform larvae having a notched tail through the Harada-Mori filter paper culture. The patient received five courses of albendazole therapy but not cured of strongyloidiasis.

Expression of a non-inactivating K+ channel driven by a rat heat shock promoter increased the resting potential in Aplysia silent neurons

We assessed the role of a non-inactivating K+ channel (aKv5.1) in the resting potential by overexpressing this channel by heat shock in the neurons. A reporter gene lacZ linked to a promoter region spanning from the -285 to the +88 base of the rat HSP70ib gene was induced 62.5-fold when this DNA construct was microinjected into the neurons of the marine mollusk Aplysia and treated with heat shock at 30 degrees C for 3 h. Using this efficient induction system, we induced the expression of aKv5.1 by heat shock in cultured, electrically silent neurons of Aplysia and examined its effect on the resting potential. The channel expression increased the resting potential by approximately 10 mV. This increase was specific to heat shock induction and abolished by treatment with TEA, a specific K+ channel blocker. These results provide the direct evidence that a low voltage-activated, non-inactivating K+ channel can contribute to the resting potential.

RNA-Stimulated ATPase and RNA helicase activities and RNA binding domain of hepatitis G virus nonstructural protein 3

Hepatitis G virus (HGV) nonstructural protein 3 (NS3) contains amino acid sequence motifs typical of ATPase and RNA helicase proteins. In order to examine the RNA helicase activity of the HGV NS3 protein, the NS3 region (amino acids 904 to 1580) was fused with maltose-binding protein (MBP), and the fusion protein was expressed in Escherichia coli and purified with amylose resin and anion-exchange chromatography. The purified MBP-HGV/NS3 protein possessed RNA-stimulated ATPase and RNA helicase activities. Characterization of the ATPase and RNA helicase activities of MBP-HGV/NS3 showed that the optimal reaction conditions were similar to those of other Flaviviridae viral NS3 proteins. However, the kinetic analysis of NTPase activity showed that the MBP-HGV/NS3 protein had several unique properties compared to the other Flaviviridae NS3 proteins. The HGV NS3 helicase unwinds RNA-RNA duplexes in a 3'-to-5' direction and can unwind RNA-DNA heteroduplexes and DNA-DNA duplexes as well. In a gel retardation assay, the MBP-HGV/NS3 helicase bound to RNA, RNA/DNA, and DNA duplexes with 5' and 3' overhangs but not to blunt-ended RNA duplexes. We also found that the conserved motif VI was important for RNA binding. Further deletion mapping showed that the RNA binding domain was located between residues 1383 and 1395, QRRGRTGRGRSGR. Our data showed that the MBP-HCV/NS3 protein also contains the RNA binding domain in the similar domain.

An inducible gene product for 6-phosphofructo-2-kinase with an AU-rich instability element: role in tumor cell glycolysis and the Warburg effect

Cancer cells maintain a high glycolytic rate even in the presence of oxygen, a phenomenon first described over 70 years ago and known historically as the Warburg effect. Fructose 2,6-bisphosphate is a powerful allosteric regulator of glycolysis that acts to stimulate the activity of 6-phosphofructo-1-kinase (PFK-1), the most important control point in mammalian glycolysis. The steady state concentration of fructose 2,6-bisphosphate in turn depends on the activity of the enzyme 6-phosphofructo-2-kinase (PFK-2)/fructose-2, 6-bisphosphatase, which is expressed in several tissue-specific isoforms. We report herein the identification of a gene product for this enzyme that is induced by proinflammatory stimuli and which is distinguished by the presence of multiple copies of the AUUUA mRNA instability motif in its 3'-untranslated end. This inducible gene for PFK-2 is expressed constitutively in several human cancer cell lines and was found to be required for tumor cell growth in vitro and in vivo. Inhibition of inducible PFK-2 protein expression decreased the intracellular level of 5-phosphoribosyl-1-pyrophosphate, a product of the pentose phosphate pathway and an important precursor for nucleic acid biosynthesis. These studies identify a regulatory isoenzyme that may be essential for tumor growth and provide an explanation for long-standing observations concerning the apparent coupling of enhanced glycolysis and cell proliferation.

A case with sarcomatoid hepatocellular carcinoma

Hepatocellular carcinoma (HCC) with sarcomatous features is a rare neoplasm which has been found in only 1.8% of surgically resected HCC and has a higher incidence of metastasis than usual HCC. We recently experienced a case of sarcomatoid HCC removed from a 49-year-old man. A surgically resected liver revealed a well-defined grayish-white solid firm mass showing extensive central necrosis and infiltrative growth margin. Microscopically, the entire tumor was composed of pleomorphic spindle cells with prominent nucleoli and frequent mitosis. It showed a sinusoidal infiltrative growth pattern at the tumor-nontumor boundary. The tumor cells reacted positively with AE3 (high molecular cytokeratin) and Vimentin and reacted negatively with AE1 (low molecular cytokeratin), cytokeratin19, carcinoembryonic antigen, alpha-fetoprotein, Factor VIII, CD31 and CD68. The spindle-shaped tumor cells were considered to originate from hepatocyte rather than from bile duct epithelium or mesenchymal elements.

Ligand binding to thrombin exosite II induces dissociation of the thrombin-heparin cofactor II(L444R) complex

Heparin cofactor II (HCII) inhibits thrombin rapidly in the presence of heparin or dermatan sulfate. The product of the inhibition reaction is a kinetically stable, 1:1 complex between the two proteins. We recently observed that heparin induces dissociation of complexes containing thrombin and the reactive site mutant HCII(L444R) to yield active thrombin and cleaved inhibitor (Han, J. -H., Van Deerlin, V. M. D., and Tollefsen, D. M. (1997) J. Biol. Chem. 272, 8243-8249). In the current study, we have investigated the mechanism by which heparin induces dissociation of the thrombin-HCII(L444R) complex. Heparin oligosaccharides >/=6 sugars in length induce dissociation, which suggests that dissociation does not depend on binding of a heparin molecule simultaneously to both proteins in the complex. Binding of heparin to HCII(L444R) in the complex also does not appear to be required, since the heparin dose response is unaltered for complexes containing the double mutant HCII(L444R/K173Q), which has decreased affinity for heparin. By contrast, binding of heparin to thrombin appears to be necessary and sufficient to induce dissociation. First, heparin fails to induce dissociation of complexes that contain thrombin(K236E), a variant with decreased heparin affinity. Second, a monoclonal IgG that interacts with the heparin-binding site of thrombin mimicks heparin in its ability to induce dissociation of the thrombin-HCII(L444R) complex. Finally, the complex of HCII(L444R) with thrombin(desPPW), which binds normally to heparin but lacks Pro60BPro60CTrp60D in an insertion loop ("60-loop") between the heparin-binding site and the catalytic site, does not dissociate in the presence of heparin. These results suggest that binding of heparin to thrombin induces an allosteric effect causing destabilization of the thrombin-HCII(L444R) complex and that the allosteric effect may be mediated by the 60-loop.

New titanium alloys for biomaterials: a study of mechanical and corrosion properties and cytotoxicity

Three new titanium alloys with Zr, Nb, Ta, Pd and In as alloying elements were developed and compared with currently used implant metals, namely, pure Ti and Ti-6Al-4V alloy, in terms of mechanical and corrosion properties, and cytotoxicity. New alloys showed comparable mechanical properties with that of the Ti-6Al-4V alloy, but increased corrosion potential, somewhat decreased breakdown potential and increased corrosion rate. There were no significant differences in cell growth on the surface of the various metal specimens, indicating that the cells cannot differentiate between the passivated surfaces of the various Ti metals.

Mutational analysis of the hepatitis C virus RNA helicase

The carboxyl-terminal three-fourths of the hepatitis C virus (HCV) NS3 protein has been shown to possess an RNA helicase activity, typical of members of the DEAD box family of RNA helicases. In addition, the NS3 protein contains four amino acid motifs conserved in DEAD box proteins. In order to inspect the roles of individual amino acid residues in the four conserved motifs (AXXXXGKS, DECH, TAT, and QRRGRTGR) of the NS3 protein, mutational analysis was used in this study. Thirteen mutant proteins were constructed, and their biochemical activities were examined. Lys1235 in the AXXXXGKS motif was important for basal nucleoside triphosphatase (NTPase) activity in the absence of polynucleotide cofactor. A serine in the X position of the DEXH motif disrupted the NTPase and RNA helicase activities. Alanine substitution at His1318 of the DEXH motif made the protein possess high NTPase activity. In addition, we now report inhibition of NTPase activity of NS3 by polynucleotide cofactor. Gln1486 was indispensable for the enzyme activity, and this residue represents a distinguishing feature between DEAD box and DEXH proteins. There are four Arg residues in the QRRGRTGR motif of the HCV NS3 protein, and the second, Arg1488, was important for RNA binding and enzyme activity, even though it is less well conserved than other Arg residues. Arg1490 and Arg1493 were essential for the enzymatic activity. As the various enzymatic activities were altered by mutation, the enzyme characteristics were also changed.

Intravascular lymphomatosis: a clinicopathological study of two cases presenting as an interstitial lung disease

AIMS

Intravascular lymphomatosis is an uncommon type of non-Hodgkin's lymphoma characterized by intravascular proliferation of neoplastic lymphoid cells. Although the tumour is basically a systemic disease, eventually involving multiple organs, primary presentation in the lung is rare.

METHODS AND RESULTS

We describe the clinicopathological features of two patients with intravascular lymphomatosis presenting in the lung. One patient complained of fever, headache and chest pain; the other, of dyspnoea on exertion and headache. Both patients showed reticulonodular density on chest radiography and decreased diffusion capacity. Lung biopsy showed features characteristic of intravascular lymphomatosis. Malignant lymphoid cells were CD30 positive T-cells of anaplastic large cell type in one patient and B-cells of large cell type in the other. There was a poor response to chemotherapy and both patients died of the disease within 3 months of diagnosis.

CONCLUSIONS

These cases and 10 previous reports illustrate the need to include intravascular lymphomatosis in the differential diagnosis of interstitial lung disease.

DNA helicase activity of the hepatitis C virus nonstructural protein 3

Hepatitis C virus (HCV) nonstructural protein 3 (NS3) is a known RNA helicase, an enzyme that unwinds RNA x DNA and RNA x RNA duplexes. We have now deciphered the biochemical characteristics of the HCV NS3 DNA helicase activity. Recombinant NS3 was expressed in Escherichia coli, purified to near homogeneity, and tested for DNA helicase activity. The optimal conditions for DNA unwinding (for example, the preferred pH and magnesium ion concentration) were similar to those for RNA unwinding. The DNA helicase activity was very sensitive to potassium ion concentration, while DNA binding and DNA-stimulated ATPase activities were not. The direction of DNA unwinding was determined to be 3' to 5'. All four ribonucleoside triphosphates (ATP, GTP, CTP, UTP) and deoxynucleoside triphosphates (dATP, dGTP, dCTP, dTTP) could serve as energy sources, but GTP and dGTP were less efficient than the others. When nucleotide analog inhibitors were added to the DNA helicase reaction, the overall order of inhibitory capacity was: adenosine 5'-O-(3-thiotriphosphate) > adenylyl-imidodiphosphate and adenylyl-(beta,gamma-methylene)-diphosphate > AMP. DNA helicase activity was inhibited strongly by ssDNA and ssRNA, but was little affected by dsDNA. The ATPase activity was stimulated greatly by ssDNA and ssRNA, but not by dsDNA. The NS3 protein could unwind up to 500 base pairs of duplex DNA. The possible multifunctional nature of the NS3 protein is discussed and compared with that of Simian virus 40 large T antigen.

Inhibition of meizothrombin and meizothrombin(desF1) by heparin cofactor II

Meizothrombin and meizothrombin(desF1) are intermediates formed during the conversion of prothrombin to thrombin by factor Xa, factor Va, phospholipids, and Ca2+ (prothrombinase). These intermediates are active toward synthetic peptide substrates but have limited ability to interact with platelets or macromolecular substrates such as fibrinogen. Meizothrombin and meizothrombin(desF1) activate protein C, however, and may exert primarily an anticoagulant effect. In this study, we investigated the inhibition of meizothrombin and meizothrombin(desF1) by two glycosaminoglycan-dependent protease inhibitors, heparin cofactor II (HCII) and antithrombin (AT). Purified recombinant meizothrombin and meizothrombin(desF1) were inhibited by HCII in the presence of dermatan sulfate with maximal second-order rate constants of 8 x 10(6) M-1.min-1 and 1.8 x 10(7) M-1.min-1, respectively, but were inhibited less than one-tenth as fast by AT in the presence of heparin. Similarly, the products of the prothrombinase reaction were inhibited in situ more effectively by HCII than by AT. When HCII and dermatan sulfate were present continuously during the prothrombinase reaction, meizothrombin was trapped as a sodium dodecyl sulfate-stable complex with HCII and no amidolytic activity could be detected with a thrombin substrate. Our findings indicate that HCII is an effective inhibitor of meizothrombin and meizothrombin(desF1) and, therefore, might regulate the anticoagulant activity of these proteases.

The role of mucosal biopsy in the diagnosis of chronic diarrhea: value of multiple biopsies when colonoscopic finding is normal or nonspecific

OBJECTIVES

There are controversies about taking routine mucosal biopsy when the gross colonoscopic finding is normal. This study was conducted to determine the frequency of clinically important histological abnormalities, prospectively, in chronic diarrhea patients with grossly normal or nonspecific colonoscopic findings.

METHODS

One hundred and eighteen patients suffering from nonbloody diarrhea with average frequency of more than two times a day for more than 4 weeks were included. Multiple biopsies (cecum, ascending colon, mid-transverse colon, descending colon, sigmoid colon and rectum) were taken during colonoscopic examinations and each biopsy specimen was reviewed by one pathologist after H&E and Masson-trichrome staining.

RESULTS

Clinically significant abnormalities (2 collagenous colitis, 1 lymphocytic colitis, 1 eosinophilic enterocolitis, 1 ulcerative colitis and 4 melanosis coli) were observed in 9 patients (7.6%). Sixteen cases (13.6%) of borderline histological abnormalities were observed (8 cases of possible collagenous colitis and 8 cases showing some features of lymphocytic colitis). Ninety two cases (78.8%) showed nonspecific inflammation only.

CONCLUSION

Clinically important histological lesions can exist in significant percentage in spite of normal or nonspecific colonoscopic findings, which can justify routine mucosal biopsy in the evaluation of chronic diarrhea patients. The clinical significance of borderline histological abnormalities needs to be determined by careful follow-up studies.

Intestinal pathologic findings at early stage infection by Centrocestus armatus in albino rats

This study was performed to observe intestinal pathology in early infection by Centrocestus armatus. The flukes were in the lowermost part of the intervillous space of the duodenum and jejunum from 1 day to 7 days postinfection (PI). The stroma of villi around the young fluke was edematous and infiltrated by inflammatory cells such as lymphocytes, plasma cells and eosinophils. The crypt became mildly hyperplastic and villi were moderately atrophied at 4 days PI. The intestinal lesion produced was confined to the areas around the fluke. The pathologic findings were not significantly different between 1,000 and 5,000 metacercariae infection groups. It is suggested that the lesion should be produced by mechanical destruction of the fluke on the enteroepithelial cells.

Towards defining a minimal functional domain for NTPase and RNA helicase activities of the hepatitis C virus NS3 protein

Hepatitis C virus (HCV) possesses two separate enzymatic functions in the NS3 protein: a protease and an NTPase/RNA helicase. In order to determine the minimal domain for NTPase and RNA helicase activities of the HCV NS3 protein, serial deletion mutants were constructed. The NS3H protein a fusion protein of 25 amino acids (aa) from an expression vector and the C-terminal 466 aa of the HCV NS3 protein, contains an NTPase/RNA helicase activity. We made deletion mutants of 10, 30, 50, 97, and 135 aa from the C-terminus and 16 and 32 aa from the N-terminus of the NS3H protein. The deleted protein lacking 50 aa from the C-terminus still possessed both activities, while the protein lacking 97 aa from the C-terminus lost an RNA helicase activity. The mutant lacking 16 amino acids from the N-terminus retained the enzymatic activities and the N-terminal 32 aa deleted mutant lost an NTPase/RNA helicase activity. A combinational deletion mutant lacking 16 aa the N-terminus and 50 aa from the C-terminus retained the enzymatic activities. These results show that the functional domain of the HCV NTPase/ RNA helicase is about 400 aa in length and maps between NS3 residues 1209 and 1608.

Heparin facilitates dissociation of complexes between thrombin and a reactive site mutant (L444R) of heparin cofactor II

Heparin cofactor II (HCII) inhibits thrombin by forming a stable 1:1 complex. Heparin and dermatan sulfate increase the rate of complex formation >/=1000-fold. Mutation of leucine 444 to arginine at the P1 position of recombinant HCII (rHCII) increases the rate of inhibition of thrombin approximately 100-fold in the absence of a glycosaminoglycan (Derechin, V. M., Blinder, M. A., and Tollefsen, D. M. (1990) J. Biol. Chem. 265, 5623-5628). We now report that heparin facilitates dissociation of the thrombin-rHCII(L444R) complex. In the presence of heparin, thrombin is inhibited rapidly and completely by a 35-fold molar excess of rHCII(L444R), but subsequently approximately 50% of the thrombin activity reappears with a t1/2 of approximately 20 min. At higher ratios of rHCII(L444R) to thrombin, the reappearance of thrombin activity is delayed and the final plateau of activity is decreased. Electrophoretic analysis indicates that proteolysis of excess rHCII(L444R) precedes the reappearance of thrombin activity. Addition of heparin at longer intervals after formation of the thrombin-rHCII(L444R) complex causes a progressive decrease in the thrombin plateau, suggesting that in the absence of heparin the complex is slowly converted to a non-dissociable form. By contrast to heparin, dermatan sulfate does not facilitate dissociation of the thrombin-rHCII(L444R) complex. Our findings indicate that the P1 residue of HCII affects not only the rate of inhibition of thrombin but also the stability of the resulting complex.

Characterization of RNA binding activity and RNA helicase activity of the hepatitis C virus NS3 protein

The Hepatitis C Virus (HCV) NS3 protein has RNA binding activity, RNA-stimulated NTPase activity, and RNA helicase activity. The RNA binding activity of the C-terminal domain of the HCV NS3 protein is less sensitive to pH, KCl, and MgCl2 than NTPase and the RNA helicase activity. The overall order of the binding of homoribopolymer for the NS3 protein was poly(U) > > poly(A) > poly(G), poly(C). The minimal RNA binding size of the HCV NS3 protein was determined using a gel retardation assay and is estimated between 7 nt and 20 nt. The HCV RNA helicase unwinds RNA/DNA heteroduplexes as well as RNA/RNA duplexes and it catalytically translocates in the 3' to 5' direction.

C-terminal domain of the hepatitis C virus NS3 protein contains an RNA helicase activity

The Hepatitis C Virus (HCV) NS3 protein contains amino acid motifs of a serine proteinase, a nucleotide triphosphatase (NTPase), and an RNA helicase based on amino acid sequence analysis. Proteinase and NTPase activities of the HCV NS3 protein were reported by several investigators. Here, we show that the recombinant HCV NS3 protein purified from a T7 promoter and His-tag expression system possesses an RNA helicase activity. The recombinant HCV NS3 protein consists of 466 amino acids from the carboxy terminal of a HCV NS3 open reading frame and 25 additional residues from the vector. The recombinant HCV NS3 protein was purified by metal-binding chromatography. The helicase activity requires ATP and divalent cations such as Mg2+ and Mn2+. The helicase activity was abolished by monoclonal antibody specific to the HCV NS3 protein.

Lymphatic delivery and pharmacokinetics of methotrexate after intramuscular injection of differently charged liposome-entrapped methotrexate to rats

The lymph node targeting ability and pharmacokinetics of methotrexate (MTX) after intramuscular (i.m.) injection of differently charged liposome-entrapped [3H]MTX to rats were evaluated using [3H]MTX as a tracer. Neutral liposomes were prepared with a mixture of phosphatidylcholine, cholesterol and alpha-tocopherol (8:4:0.1, molar ratio). Positively and negatively charged liposomes were also prepared by incorporation of stearylamine (8:4:0.1, molar ratio) and dicetylphosphate (8:4:0.1:1, molar ratio) into neutral liposomes respectively. The encapsulation efficiency (as expressed in terms of radioactivity) in liposomes was increased as alpha-tocopherol was incorporated into the lipid bilayer. The disappearance of [3H]MTX from the i.m. injection site was rapid and essentially complete after 30 min. On the other hand, the disappearance of radioactivity of liposome-entrapped [3H]MTX was much slower when compared to free drug. The area under the drug concentration-time curve (AUC) of liposome-entrapped [3H]MTX in lymph nodes was significantly increased when compared to free [3H]MTX. It suggested that liposomes injected by the i.m. route entered into the lymphatics and only drug released from liposomes diffused directly into the systematic circulation. The liposome-entrapped [3H]MTX by i.m. route was markedly localized in the lymph nodes. The concentration of MTX-equivalents in regional lymph node after i.m. injection of liposome-entrapped [3H]MTX was > 100-350 fold higher when compared to the plasma concentration. These values are more than 10-20 fold higher compared to the i.m. injection of free [3H]MTX. The positively charged liposomes were more localized in lymph nodes compared to neutral and negatively charged ones. While liposomes injected by i.v. route were localized in liver, spleen and lung compared to free [3H]MTX, it was evident that i.m. administration of liposomes resulted in enhanced localization of MTX in the lymphatic system but decreased deposition in kidney, liver and other non-targeting tissues compared to free [3H]MTX. The targeting ability and carrier properties of liposome-entrapped anticancer drugs with varying surface charge, lipid compositions and route of administration are of significant importance to alter biodistribution in chemotherapy.

Regulation of corticotropin-releasing factor secretion and synthesis in the human neuroblastoma clones- BE(2)-M17 and BE(2)-C

The BE(2)-M17 and BE(2)-C human neuroblastoma cell lines have been shown to synthesize and secrete corticotropin-releasing factor (CRF) following retinoic acid treatment. It has been demonstrated that CRF secretion and intracellular synthesis increases in response to forskolin treatment. In this report, we have further characterized these cells in response to protein kinase C activators, dexamethasone, interleukin-1 alpha, as well as various neurotransmitters and peptides. Nanomolar concentrations of the phorbol ester--phorbol 12 myristate 13--acetate (TPA), increased intracellular CRF content in both cell lines while increasing secretion only in the BE(2)-M17 cell. Nanomolar concentrations of dexamethasone were not able to alter basal levels of secretion and content in either cell type. However, in the BE(2)-M17 cell but not the BE(2)-C cell, the same concentrations of dexamethasone added to 30 microM forskolin augmented levels of CRF secretion and content. Likewise, the same augmented response in CRF secretion and content was seen only in the BE(2)-M17 cell line when nanomolar concentrations of dexamethasone were added to 20 nM TPA. Furthermore, only in the BE(2)-M17 cell line were micromolar levels of the biogenic amine serotonin able to increase levels of CRF secretion and content. No effects on CRF in both cell lines were demonstrable with picomolar levels of interleukin-1 alpha as well as micromolar levels of acetylcholine, norepinephrine, arginine-vasopressin, oxytocin, and angiotensin-II. The potential usefulness of these cells as models of central nervous system or placental CRF-containing neurons is discussed.

Modulation of apoptosis in human myeloid leukemic cells by GM-CSF

Apoptosis (programmed cell death) regulates cell population size. To determine the mechanisms whereby hematopoietic growth factors (HGFs) modulate apoptosis in human myeloid leukemic cells, we evaluated the roles of protein and mRNA synthesis for altering apoptosis in growth factor-stimulated vs. quiescent leukemic TF1 cells. Lysates of cells from the granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent myeloid leukemic cell line TF1 were separated into high molecular weight (HMW) pellets of intact DNA and supernatants of fragmented low MW (LMW) DNA, and the DNA purified from these fractions was quantified. In the absence of both GM-CSF and fetal bovine serum (FBS), 70% of the DNA was fragmented after 3 days in culture, with a characteristic apoptotic ladder-like pattern on agarose gel electrophoresis, whereas this proportion had initially been < 5%. In contrast, less than 5% of the DNA was fragmented in cells incubated with GM-CSF plus FBS or GM-CSF alone. Delayed addition of GM-CSF, but not FBS, permitted partial rescue of the cells, inhibiting increasing rates of accumulation of fragmented DNA. When the macro-molecular synthesis inhibitor cycloheximide (CHX) or actinomycin D (Act D) was present for 26 hours in the absence of GM-CSF and FBS, apoptosis was inhibited. In contrast, in the presence of GM-CSF or FBS, apoptosis was enhanced upon addition of CHX or Act D. The latter effect persisted even with the late addition of CHX. These findings indicate that disparate mechanisms of enhancing or inhibiting apoptosis exist in myeloid leukemic cells related to environmental conditions, including HGF-regulated cellular synthesis of distinct proteins and mRNA.

Hemodynamic adaptations at birth and neonates delivered vaginally and by Cesarean section

In order to assess the possible influence of differences in delivery mode on cardiovascular adaptation at birth, we measured left ventricular output and its regional distribution in the major organs sequentially using an echographic technique during the first 96 h of life. We studied 27 normal newborns, of whom 15 were delivered vaginally and 12 by cesarean section. We also measured umbilical arterial and venous catecholamine concentrations. The umbilical arterial epinephrine and norepinephrine concentrations in the infants delivered vaginally were significantly greater than those in the infants delivered by cesarean section (epinephrine 1,195 +/- 208 vs. 565 +/- 81 pg/ml, p < 0.05; norepinephrine 11,832 +/- 3,819 vs. 5,153 +/- 1,400 pg/ml, p < 0.05). The left ventricular output and its regional distribution showed a similar pattern in the two groups, and there were no significant differences between them. These results indicate that the capacity of infants delivered by cesarean section to tolerate cardiovascular changes during the early neonatal period is comparable to that in infants delivered vaginally, even though there are significant differences in the catecholamine surge between these groups.

Transfection of a differentiated human hepatoma cell line (Huh7) with in vitro-transcribed hepatitis C virus (HCV) RNA and establishment of a long-term culture persistently infected with HCV

T7 RNA polymerase transcripts of a putative full-length cDNA clone of hepatitis C virus type 1 (HCV-1) were used to transfect a differentiated human hepatoma cell line, Huh7. The transfected genome replicated in cells, as evidenced by the appearance of progeny HCV RNA, detection of negative-strand viral RNA, and incorporation of [3H]uridine into the viral genome. Incubation of naive Huh7 cells with conditioned medium from transfected cells resulted in a new HCV infection, suggesting the production of biologically active virus in the inoculum. Maintenance of the transfected cells under serum-free culture conditions resulted in the selection of persistently infected cells which displayed a distinctive cellular morphology. This is the first demonstration that HCV RNA produced from cloned HCV cDNA is infectious and replication competent. This approach should provide a valuable system for studying HCV replication, persistence, and pathogenicity.

Interleukin-1 alpha induces corticotropin-releasing factor secretion and synthesis from NPLC-KC cells through various second messenger pathways

Interleukin-1 (IL1) is a key messenger implicated in endocrine and immune systems that interact to mediate the stress response. Corticotropin-releasing factor (CRF) secretion and synthesis in the NPLC-KC human hepatoma cell line has been shown to respond to IL1 stimulation. We have studied how various inhibitors of second messenger pathways alter this IL1 effect. NPLC-KC cells were grown in six-well Costar plates and treated for 12 or 24 h with or without 500 pM IL1 (alpha form) in the presence of various inhibitors of second messenger pathways. Inhibitors included the protein kinase C (PKC) inhibitor, H-7; the protein kinase A inhibitor, IP20; or the cyclooxygenase inhibitor indomethacin (IND). Both cell extracts and secretion media were assayed for CRF-like immunoreactivity by radioimmunoassay. IP20, H-7, and IND all reduced basal CRF secretion at 24 h but not at 12 h. No effects were seen on basal CRF synthesis with these inhibitors. The three inhibitors also reduced IL1 effects on CRF secretion at 12 and 24 h. The reduction seen with all three inhibitors was statistically significant (P < 0.05) at 12 h. Although a reduction was seen with all three inhibitors at 24 h, a statistically significant reduction (P < 0.05) was demonstrable only for H-7. IL1 stimulated CRF synthesis in the NPLC-KC cells appears to only involve PKC pathways. Only the PKC inhibitor H-7 reduced the augmentation that IL1 produces on CRF synthesis. This effect was statistically significant at 12 and 24 h (P < 0.05).

Natural interferon-alpha versus its combination with 6-methyl-prednisolone in the therapy of type II mixed cryoglobulinemia: a long-term, randomized, controlled study

Type II mixed cryoglobulinemia (MC) is an often progressive vasculitis characterized by circulating cold-precipitable proteins that usually consists of polyclonal IgG and monoclonal IgM kappa with rheumatoid factor (RF) activity. Its etiology is unknown, although recent evidence strongly suggests that hepatitis C virus (HCV) plays a major role. Plasmapheresis, corticosteroids, and cytotoxic drugs have been used in the therapy of MC patients. Recently, favorable results with recombinant interferon-alpha (rIFN alpha) have been reported. To further assess its effectiveness, we studied the effects of natural human interferon-alpha (nIFN alpha), alone and in combination with 6-methyl-prednisolone (PDN), in a prospective, randomized, controlled trial in patients with symptomatic MC. Sixty-five patients were enrolled onto the trial, 52 (80%) of whom presented serum anti-HCV antibodies and specific genomic RNA sequences. Fifteen patients received nIFN alpha (3 MU) intramuscularly (IM) three times weekly, whereas 17 patients also received 16 mg/d of PDN orally on non-IFN days. Moreover, 18 patients received 16 mg/d of PDN only, and 15 were untreated. Treatment was discontinued after 1 year and patients were monitored for 8 to 17 months (mean, 13). A complete response was achieved in eight of 15 patients (53.3%) treated with nIFN alpha and nine of 17 (52.9%) treated with nIFN alpha plus PDN, as compared with three of 18 patients (16.7%) who received PDN only (P < .05) and one of 15 (6.7%) untreated controls (P < .01). Partial response occurred in two of 15 (13.3%) patients treated with nIFN alpha, three of 17 (17.6%) who received nIFN alpha plus PDN, one of 18 (5.5%) who received PDN only, and one of 15 (6.7%) controls. A complete response in six patients (66.7%) was achieved within 3 months in the group that received nIFN alpha plus PDN, as compared with two patients (25%) of those who received nIFN alpha alone (P < .02). In anti-HCV-positive patients, the clinical response occurred in step with reduced or undetectable levels of HCV RNA and transaminase normalization. Quantification of circulating HCV RNA represented a good predictive response marker. The probability of relapse within 3 months after treatment was 100% (three of three patients) and 75% (six of eight patients), respectively, in patients who received PDN alone or nIFN alpha alone as compared with none of those who received nIFN alpha plus PDN (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

The BE (2)-M17 neuroblastoma cell line synthesizes and secretes corticotropin-releasing factor

The BE (2)-M17 human neuroblastoma has previously been shown to express corticotropin-releasing factor (CRF) mRNA following retinoic acid treatment. It is demonstrated in this report that both cell extracts and cell incubation medium of retinoic acid-treated BE (2)-M17 cells were shown to contain CRF-like immunoreactivity (CRF-LI) by RIA. CRF-LI secretion and content were also dose-dependently increased by forskolin. In addition, cell extracts were applied to a C18 Vydac column and peak CRF-LI from the collected fractions was shown to coincide in time of elution with peak immunoreactivity seen with oxidized synthetic CRF standard. Thus, in containing the CRF peptide, the BE (2)-M17 cells are useful models for further study of CRF cellular and genetic regulation.

Increased serum soluble interleukin-2 receptors in Caucasian and Korean schizophrenic patients

Recent studies have identified immunologic abnormalities in some schizophrenic subjects. This experiment replicates previous findings that serum soluble interleukin-2 receptors (SIL-2Rs) are elevated in schizophrenic patients, and is the first study to describe this phenomenon in non-Caucasian patients. Despite differences between Korean and Caucasian schizophrenic patients in absolute serum SIL-2R levels, both groups were significantly elevated when compared with their respective ethnic control groups (477 +/- 171 U/ml versus 354 +/- 172 U/ml and 763 +/- 347 U/ml versus 567 +/- 231 U/ml, respectively). Neither age, gender, medication status, nor duration of illness correlated with SIL-2R levels. These findings are further evidence that immune activation is present, regardless of ethnic origin, in some schizophrenic patients.

Effect of noise on the detection of rib fractures by residents

RATIONALE AND OBJECTIVES

The authors assessed the effect of noise on the detectability of rib fractures by residents.

METHODS

Eight radiology residents read chest posterior-anterior radiographs of 92 subjects with rib fracture(s) and 28 normal subjects to detect rib fracture(s) according to a five-point scale of confidence, under quiet and "noisy" conditions. Each individual's attitude toward noise was measured by a multiple-choice questionnaire.

RESULTS

The readers were divided into two groups depending on the questionnaire result: group A readers were accustomed to a quiet environment, and group B readers were accustomed to noisy environments or were unaffected by noise. Group A's performance, measured by the area (Az) under the receiver operating characteristic (ROC) curve, was better in quiet conditions when compared with their performance in noisy conditions; however, the opposite tendency was observed for group B. There was a significant individual difference of performance in response to noise.

CONCLUSION

Effect of noise on the detection of rib fractures depends on an individual's attitude toward sound and noise.

Corticotropin-releasing factor is secreted in the BE(2)-C neuroblastoma cell and is responsive to forskolin

The BE(2)-C human neuroblastoma has been shown to express corticotropin-releasing factor (CRF) messenger RNA. In this study, BE(2)-C cells were treated 5 days with 5 microM retinoic acid. Cell extracts were also applied onto a C18 Vydac column and fractions were assayed for CRF-like immunoreactivity (CRF-LI) which coincided in time of elution with oxidized or non-oxidized CRF synthetic CRF standard. With forskolin treatment, secretion media and cell extract CRF-LI increased in a concentration-dependent fashion. Thus, this cell line synthesizes and secretes CRF and is a good model for studying CRF regulation.

Detection of hepatitis C virus RNA: comparison of one-stage polymerase chain reaction (PCR) with nested-set PCR

We evaluated a new hepatitis C virus RNA assay based on one-stage PCR followed by liquid hybridization with an oligonucleotide probe and compared it with nested-set PCR. The one-stage and nested-set PCR assays had identical sensitivities in analytical experiments and showed 100% concordance when clinical specimens were used. One-stage PCR may be less prone to contamination than nested-set PCR.

Diagnostic value of exclamation mark hairs

Exclamation mark (EM) hair can lead to the misdiagnosis of alopecia areata (AA) because it is widely considered as pathognomonic for AA. Typical EM hairs were also found in trichotillomania. EM hairs collected from 2 cases of trichotillomania and 9 cases of AA were compared under light microscopy. There were two sorts of EM hairs, one with frayed distal ends and the other with blunt distal ends. The majority (77.8%) of the EM hairs from AA had frayed distal ends, while the majority (82.2%) of that from trichotillomania had blunt distal ends. EM hairs, even with frayed distal ends, are not pathognomonic of AA.

Long term treatment of chronic hepatitis C with interferon alfa-2b: disappearance of HCV-RNA in a pilot study of eight haemophilia patients

This pilot study was designed to establish the effect of long term alpha interferon treatment in haemophilia patients with chronic hepatitis C. Overall, three of eight (37.5%) patients showed a complete response, three of eight (37.5%) a transient response, and two of eight (25.0%) no response. HCV-RNA detection by polymerase chain reaction was more sensitive in detecting relapse than alanine amino-transferase (ALT) activity measurement, suggesting that current interferon schedules based on the ALT response should be re-evaluated critically.

5' end-dependent translation initiation of hepatitis C viral RNA and the presence of putative positive and negative translational control elements within the 5' untranslated region

Hepatitis C virus (HCV) is a distant relative of pestiviruses and flaviviruses, but it has a 5' untranslated region (UTR) with some features structurally similar to that of picornaviruses. In order to test the role of the 5' UTR in controlling the expression of the HCV polyprotein, we fused full-length or deleted versions of the 5' UTR of HCV-1 RNA to chloramphenicol acetyl transferase (CAT) mRNA to monitor CAT activity in vivo. We found: (1) the full-length 5' UTR of HCV-1 RNA is translationally inactive while 5' deletions which mimic a 5' subgenomic RNA detected in vivo are active, (2) an efficient cis-acting element which represses translation is found at the 5' terminus, (3) a putative element which enhances translation is found near the 3' terminus of the 5' UTR, (4) additional cis-acting elements including small open reading frames (ORFs) upstream from the putative enhancer element downregulate translation. We did not find evidence supporting the existence of an internal ribosome entry site in the 5' UTR of HCV-1 RNA. These data suggest that HCV may employ a distinctive translation control strategy such as the generation of subgenomic viral mRNA in infected cells. Translational control of HCV might be responsible for some of the characteristic pathobiology seen in viral infection.

[Comparative study on the effectiveness of modified Kato's cellophane thick smear and Stoll's dilution egg counting technique for quantitative fecal examination of helminth eggs]

A total of 197 fecal specimens was prepared for quantitative examination of helminth eggs by modified Kato's cellophane thick smear (M.C.T.S.) and Stoll's dilution egg counting technique (D.E.C.T.). The comparative effectiveness of two techniques was evaluated and conversion function was deduced. The average time required for the microscopic examination on one slide by M.C.T.S. was 12.6 minutes and that of D.E.C.T. was 14.6 minutes. M.C.T.S. showed lower false negative rate than D.E.C.T. in light worm burden cases. Functions to convert the counts obtained by M.C.T.S. to E.P.G. by Stoll's dilution egg counting technique were 47.86 x 10(0.87) logM.C.T.S. in A. lumbricoides, 41.69 x 10(0.82) logM.C.T.S. in T. trichiura and 63.10 x 10(0.85) logM.C.T.S. in C. sinensis. It was suggested M.C.T.S. be better than D.E.C.T. for the quantitative examination of intestinal helminthiases such as A. lumbricoides, T. trichiura, and C. sinensis infections even in the cases with low worm burden.

Tissue and species differences in bile salt-dependent neutral cholesteryl ester hydrolase activity and gene expression

Enzymatic activity and mRNA abundance for neutral bile salt-dependent cholesteryl ester hydrolase (CEH) were determined in rat and rabbit tissues. In rat liver and intestine, enzyme activity and mRNA levels varied independently. Particularly striking in most tissue samples was the absence of detectable CEH mRNA in the presence of enzymatic activity, suggesting that there was an exogenous source of enzyme. Rabbits differed from rats in four ways. First, neither CEH activity nor mRNA was present in any liver sample. Second, CEH mRNA was present in nearly all intestinal samples, and its abundance tended to correlate with enzymatic activity. Third, rabbit CEH mRNA was approximately 250 bases shorter than the rat message. Fourth, we have previously shown that rat plasma contains CEH activity, whereas in the present studies, rabbit plasma did not contain such activity. Overall, our studies indicate that CEH activity in rat liver, intestine, and plasma can be derived exogenously, most likely from the uptake and transport of pancreatic enzyme. In contrast, in rabbit the lack of CEH activity in plasma and liver and the capacity of the intestine for in situ synthesis of CEH suggest that this animal does not have the same ability to distribute pancreatic CEH. These species differences in CEH metabolism may partly explain the greater susceptibility of rabbit tissues to accumulate cholesteryl esters.

The melanoma growth stimulatory activity receptor consists of two proteins. Ligand binding results in enhanced tyrosine phosphorylation

The human melanoma growth-stimulatory activities (MGSA alpha, beta, gamma/GRO) are products of immediate early genes coding for cytokines that exhibit sequence similarity to platelet factor-4 and beta-thromboglobulin. MGSA/GRO alpha has been demonstrated to partially complete for binding to the approximately 58-kDa neutrophil receptor for another beta-thromboglobulin-related chemotactic protein, IL-8. We demonstrate that when [125I]MGSA/GRO alpha was cross-linked to receptors/binding proteins from human placenta, there were two major [125I]MGSA cross-linked bands of approximately 64,000 and approximately 84,000 Mr. Because [125I]MGSA exists primarily in monomer and dimer forms at the concentrations used here, it is not clear whether the receptor/binding proteins represented by the cross-linked bands are approximately 50,000 and approximately 70,000 or approximately 58,000 and approximately 78,000 Mr. Ligand binding to the receptor proteins is associated with enhanced tyrosine phosphorylation of a number of substrates, including proteins in the same Mr range as the MGSA/GRO receptor/binding proteins.

The melanoma growth stimulatory activity receptor consists of two proteins. Ligand binding results in enhanced tyrosine phosphorylation

The human melanoma growth-stimulatory activities (MGSA alpha, beta, gamma/GRO) are products of immediate early genes coding for cytokines that exhibit sequence similarity to platelet factor-4 and beta-thromboglobulin. MGSA/GRO alpha has been demonstrated to partially complete for binding to the approximately 58-kDa neutrophil receptor for another beta-thromboglobulin-related chemotactic protein, IL-8. We demonstrate that when [125I]MGSA/GRO alpha was cross-linked to receptors/binding proteins from human placenta, there were two major [125I]MGSA cross-linked bands of approximately 64,000 and approximately 84,000 Mr. Because [125I]MGSA exists primarily in monomer and dimer forms at the concentrations used here, it is not clear whether the receptor/binding proteins represented by the cross-linked bands are approximately 50,000 and approximately 70,000 or approximately 58,000 and approximately 78,000 Mr. Ligand binding to the receptor proteins is associated with enhanced tyrosine phosphorylation of a number of substrates, including proteins in the same Mr range as the MGSA/GRO receptor/binding proteins.