Use of a gamma-2 herpesvirus as a vector to deliver antibodies to rhesus monkeys

The gamma-2 herpesvirus of rhesus monkeys, rhesus monkey rhadinovirus (RRV), persists principally in B cells of its host. We constructed recombinant strains of RRV expressing the rhesus monkey-derived anti-SIV monoclonal antibodies 4L6 and 5L7 and compared the RRV-mediated in vivo delivery of these antibodies in rhesus monkeys with previous studies that utilized intramuscular delivery with an adeno-associated virus (AAV) vector. Recombinant RRV-4L6 and RRV-5L7 were both shown to stably produce the antibodies in persistently infected B-cell lines in culture. Two RRV-negative rhesus monkeys were experimentally infected with recombinant RRV-4L6 and two with recombinant RRV-5L7. Following infection, the appearance of the delivered antibody was readily detected in all four animals. However, the levels of the delivered antibody were considerably lower than what has been typically observed following intramuscular AAV delivery. Furthermore, three of the four monkeys had an antibody response to the delivered antibody as had been observed previously with intramuscular AAV delivery of these same antibodies. We conclude that this recombinant herpesvirus has no inherent advantage over AAV for delivery of potentially therapeutic monoclonal antibodies in a rhesus monkey model.

Inexplicable Outcome of Early Appearance of Hepatocellular Carcinoma in the Allograft After Deceased Donor Liver Transplantation: A Case Report

BACKGROUND

This case represents the earliest appearance of de novo HCC after liver transplantation (OLT) compared with cases of previously reported literatures.

CASE REPORT

A 45-year-old man underwent deceased donor OLT owing to decompensated liver cirrhosis. He had YMDD viral mutation and hepatitis B (HBV) and C (HCV) coinfection but no tumor was found in the liver on MRI before OLT. The donor was a healthy young female donor who was HCV and HBV negative. There was no tumor in the explant liver. After OLT, HCV RNA and hepatitis B surface antigen became undetectable with DNA-positive HBV. Nine months after OLT, a computed tomography (CT) scan was performed owing to abdominal pain, detecting a mass occupying the right lobe that depicted enhanced characteristics typical of HCC. The chest CT demonstrated metastatic lung nodules in the right basal lower lobe. Fluorescence in situ hybridization showed tumor cells from the recipient.

CONCLUSIONS

To the best of our knowledge, this is the first report of de novo hepatocellular carcinoma that has emerged within a short period of undergoing OLT.

Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene

We investigate the transient photoconductivity of graphene at various gate-tuned carrier densities by optical-pump terahertz-probe spectroscopy. We demonstrate that graphene exhibits semiconducting positive photoconductivity near zero carrier density, which crosses over to metallic negative photoconductivity at high carrier density. These observations can be accounted for by the interplay between photoinduced changes of both the Drude weight and carrier scattering rate. Our findings provide a complete picture to explain the opposite photoconductivity behavior reported in (undoped) graphene grown epitaxially and (doped) graphene grown by chemical vapor deposition. Notably, we observe nonmonotonic fluence dependence of the photoconductivity at low carrier density. This behavior reveals the nonmonotonic temperature dependence of the Drude weight in graphene, a unique property of two-dimensional massless Dirac fermions.

Perfusion defects detected after liver transplantation on multidetector computerized tomography: short- and long-term follow-up

BACKGROUND

Perfusion defects are sometimes found during the follow-up computerized tomography (CT) after liver transplantation (OLT). This study sought to determine the short- and long-term outcomes of perfusion defects observed after OLT with the use of multidetector CT.

METHODS

From February 4, 2004, to December 8, 2011, a total 46 LTs were performed in our hospital owing to end-stage liver cirrhosis (n = 43), liver cirrhosis with hepatocellular carcinoma (HCC; n = 1), combined HCC with cholangiocellular carcinoma (CCC; n = 1), or hepatic failure from acute hepatitis A (n = 1). The transplanted livers were procured from cadaveric (n = 24) or living related donors (n = 22). The average age of the recipient was 53.3 ± 10.4 years. The male-female ratio was 30:16. Postoperative multidetector CT was performed with a dynamic sequence in 203 examinations and with a portal phase in 46 examinations. The contrast media was Radisense. The rate of injection of 120 mL was 3 mL/s with a power injector; the iodine concentration was 300 or 370 mg/dL. Follow-up ranged from 3 months 3 days to 7 years 363 days. We classified perfusion defects as chronic segmental or subsegmental benign ischemia, transient focal perfusion defects, benign subcapsular ischemia, or fatal whole liver perfusion defects.

RESULTS

There were 3 cases of chronic segmental or subsegmental benign ischemia, 8 focal transient perfusion defects, 1 benign subcapsular ischemia, and 4 fatal whole liver perfusion defects. Except the fatal cases, all other perfusion defects occurred in the courses of benign conditions without resection or reoperation.

CONCLUSIONS

Most perfusion defects were benign and uneventful, requiring no treatment, with the exception of fatal whole liver perfusion defects, which resulted in death after detection.

Cryoprotection of fibroblasts by carboxylated poly-L-lysine upon repeated freeze/thaw cycles

The cryoprotection of carboxylated h-poly-L-lysine (COOH-PLL) was investigated on fibroblasts [L-929 cells and human dermal fibroblasts (HDFs)] during multiple freeze/thaw cycles. COOH-PLL was not toxic to two fibroblast cell types even at 25% (w/v) concentration, whereas dimethylsulphoxide (DMSO) was highly toxic over 3.13% (v/v). When L-929 cells were subjected to 5 freeze/thaw cycles, the media containing 7.5% (w/v) COOH-PLL maintained cell morphology and significantly suppressed growth inhibition as well as cell detachment (P < 0.05). The result was comparable to the media containing 10% (v/v) DMSO. For HDFs, COOH-PLL could effectively retain cell viability and proliferation against 3 freeze/thaw cycles. Cell viability of HDFs was decreased after 5 freeze/thaw cycles, but COOH-PLL exerted better cryoprotection. The cell type might account for the difference in the observations. The data demonstrated that COOH-PLL is a good cryoprotectant for mammalian cells against repeated freeze/thaw cycles, and may be used for cell preservation in fields of cell transplantation, tissue engineering and regenerative medicine.

Beneficial effects of Undaria pinnatifida ethanol extract on diet-induced-insulin resistance in C57BL/6J mice

This study was performed to evaluate the beneficial effect of Undaria pinnatifida ethanol extract (UEFx) on insulin resistance in diet-induced obese mice. A high-fat diet was supplemented with the UEFx at 0.69% (wt/wt) dose, which contains an equivalent amount of 0.02% fucoxanthin (wt/wt), or with Fx at 0.02% (wt/wt) dose in diet. After 9 weeks, both UEFx supplement significantly lowered the amount of visceral fat, the size of adipocyte, the fasting blood glucose concentration, the plasma insulin and the insulin resistance index similar to pure as shown by Fx supplement, compared to the high-fat (HF) control group. Blood glucose level was negatively correlated with hepatic glucokinase activity (r = -0.533, p < 0.05), whereas positively correlated with hepatic gluconeogenic enzyme activities (r = 0.463, p < 0.05 for glucose-6-phosphatase; r = 0.457, p < 0.05 for phosphoenolpyruvate carboxykinase). Ratio of hepatic glucokinase/glucose-6-phosphatase and glycogen content were significantly elevated by the UEFx and Fx supplements. Supplementation of the UEFx as well as Fx seemed to stimulate the β-oxidation activity and inhibit the phosphatidate phosphohydrolase activity resulting in a decrease in the hepatic lipid droplet accumulation. The results indicate that the UEFx can prevent insulin resistance and hepatic fat accumulation that is partly mediated by modulating the hepatic glucose and lipid homeostasis in the high fat-induced obese mice.

Rodent-specific hypoxia response elements enhance PAI-1 expression through HIF-1 or HIF-2 in mouse hepatoma cells

Plasminogen activator inhibitor-1 (PAI-1) is an important regulator of numerous pathophysiological processes such as inflammation, thrombosis, angiogenesis and tumor metastasis. Its expression is induced by hypoxia at the transcriptional level, via the hypoxia inducible factor-1 (HIF-1) or -2 (HIF-2). In this study, we elucidated the mechanism of transcriptional regulation of mouse PAI-1 gene by hypoxia in mouse hepatoma cells. We searched for hypoxia response elements (HREs) of murine PAI-1 promoter using several molecular biological assays. DNAse I hypersensitivity assay first suggested that PAI-1 gene expression is up-regulated by protein-DNA interactions at the -3.6- and -3-kb upstream regions of the PAI-1 gene transcription start site. An approximately 6.4-kb region of DNA containing the 5'-flanking promoter region of the PAI-1 gene was isolated, mapped, and cloned into reporter gene assay vectors and sequenced. Luciferase reporter gene assay subsequently identified two functional HREs, located around -3.6 kb of the 5'-flanking promoter region of PAI-1 gene that were responsible for the enhancement of luciferase reporter gene activity. Mutation of the HREs in this fragment abolished luciferase reporter gene activity. Finally, in vitro and in vivo protein-DNA interaction assays confirmed binding of the two HREs to HIF-1 or HIF-2 protein. Our results show that two HREs located around -3.6 kb of the 5'-flanking promoter region of the mouse PAI-1 gene function as hypoxia enhancers, which, alongside other regulatory regions, control PAI-1 gene transcription by HIF-1 or HIF-2 under hypoxic environments in mouse hepatoma cells.

Distribution and determinants of maximal physical work capacity of Korean male metal workers

The distribution of maximal physical work capacity (MPWC) can be used to establish an upper limit for energy expenditure during work (EEwork). If physically demanding work has wearing effects, there will be a negative relationship between MPWC and workload. This study was conducted to investigate the distribution of MPWC among Korean metal workers and to examine the relationship between workload and MPWC. MPWC was estimated with a bicycle ergometer using a submaximal test. Energy expenditure was estimated by measuring heart rates during work. The study subjects were 507 male employees from several metal industries in Korea. They had a lower absolute VO2max than the Caucasian populations described in previous studies. The older workers had a lower physical capacity and a greater overload at work. A negative relationship was found between MPWC and workload across all age groups. Upper limits for EEwork for all age groups and for older age groups are recommended based on the 5th percentile value of MPWC.

Modeling and experimental verification of plasmas induced by high-power nanosecond laser-aluminum interactions in air

It has been generally believed in literature that in nanosecond laser ablation, the condensed substrate phase contributes mass to the plasma plume through surface evaporation across the sharp interface between the condensed phase and the vapor or plasma phase. However, this will not be true when laser intensity is sufficiently high. In this case, the target temperature can be greater than the critical temperature, so that the sharp interface between the condensed and gaseous phases disappears and is smeared into a macroscopic transition layer. The substrate should contribute mass to the plasma region mainly through hydrodynamic expansion instead of surface evaporation. Based on this physical mechanism, a numerical model has been developed by solving the one-dimensional hydrodynamic equations over the entire physical domain supplemented by wide-range equations of state. It has been found that model predictions have good agreements with experimental measurement for plasma front location, temperature, and electron number density. This has provided further evidence (at least in the indirect sense), besides the above theoretical analysis, that for nanosecond laser metal ablation in air at sufficiently high intensity, the dominant physical mechanism for mass transfer from the condensed phase to the plasma plume is hydrodynamic expansion instead of surface evaporation. The developed and verified numerical model provides useful means for the investigation of nanosecond laser-induced plasma at high intensities.

Chromosome aberration and lipid peroxidation in chromium-exposed workers

Chromosome aberration frequency and lipid peroxidation levels were analyzed to investigate their efficacy as biological markers for monitoring the genotoxicity and oxidative damage in Korean chromium (Cr)-exposed workers. Fifty-one Cr-exposed workers and 31 age-matched controls in ten chrome-plating plants were sampled. The Cr level was measured in the workers' blood and urine, and in the ambient air at the workplaces. The conventional Giemsa staining method and fluorescence in situ hybridization (FISH) technique were used for chromosome aberration analysis. Spectrum green whole chromosome paint specific for chromosome 4 was used in the FISH procedure. As for lipid peroxidation, malondialdehyde (MDA) was measured in the blood plasma as thiobarbituric acid-reactive substances (TBARS). The blood Cr concentration was statistically correlated with both the frequency of chromatid exchange and the total frequency of chromosome/chromatid breaks and exchanges, as detected by the Giemsa staining. Meanwhile, the frequency of translocation, as detected by the FISH technique, was significantly higher in the Cr-exposed workers than in the controls and it correlated with the blood Cr concentration. Although the concentration of MDA, the metabolite of lipid peroxidation, in the exposed workers was higher than that of the controls, no statistically significant correlation between the MDA level and the blood or urine Cr levels was observed. Accordingly, the genotoxicity and oxidative damage (plasma lipid peroxidation) in the Korean Cr-exposed workers were consequential at quite low exposure levels, plus chromosome rearrangement, especially translocation, was clearly evident as a biological response marker for Cr exposure based on a significant positive correlation between the translocations detected by FISH and the Cr in the blood.

Comparison of myocardial infarction with sequential ligation of the left anterior descending artery and its diagonal branch in dogs and sheep

We report a comparison of the effects of myocardial infarction in dogs and sheep using sequential ligation of the left anterior descending artery (LAD) and its diagonal branch (DA), with hemodynamic, ultrasonographic and pathological evaluations. Five animals were used in each group. After surgical preparation, the LAD was ligated at a point approximately 40% of the distance from the apex to the base of the heart, and after one hour, the DA was ligated at the same level. Hemodynamic and ultrasonographic measurements were performed preligation, 30 minutes after LAD ligation, and 1 hour after DA ligation. As a control, two animals in each group were used for the simultaneous ligation of the LAD and the DA. Two months after the coronary ligation, the animals were evaluated as previously, and killed for postmortem examination of their hearts. All seven animals in the dog group survived the experimental procedures, while in the sheep group only animals with sequential ligation of the LAD and DA survived. Statistically significant decreases in systemic arterial blood pressure and cardiac output, and an increase in the pulmonary artery capillary wedge pressure (PACWP) were observed one hour after sequential ligation of the LAD and its DA in the sheep, while only systemic arterial pressures decreased in the dog. Ultrasonographic analyses demonstrated variable degrees of anteroseptal dyskinesia and akinesia in all sheep, but in no dogs. Data two months after coronary artery ligation showed significant increases in central venous pressure, pulmonary artery pressure, and PACWP in the sheep, but not in the dog. Left ventricular end-diastolic dimension and left ventricular end-systolic dimension in ultrasonographic studies were also increased only in the sheep. Pathologically, the well-demarcated thin-walled transmural anteroseptal infarcts with chamber enlargement were clearly seen in all specimens of sheep, and only-mild-to-moderate chamber enlargements with endocardial fibrosis were observed in the dog hearts. In conclusion, this study confirms that the dog is not a suitable model for myocardial infarction with failure by coronary artery ligation despite negligent operative mortality, when compared directly with an ovine model.

Double-blind naltrexone and placebo comparison study in the treatment of pathological gambling

BACKGROUND

The authors' goal was to assess the efficacy and tolerability of naltrexone in the treatment of pathologic gambling disorder.

METHODS

Eighty-three subjects who met criteria for DSM-IV pathologic gambling disorder were enrolled in a 1-week single-blind placebo lead-in followed by an 11-week double-blind naltrexone or placebo trial. Naltrexone was started at 25 mg/day and titrated upward until maximum symptom improvement or 250 mg/day was achieved. Gambling symptom change was assessed with the patient-rated Clinical Global Impression (PG-CGI-PT), clinician-rated CGI (PG-CGI-MD), and the Gambling Symptom Rating Scale (G-SAS). Side effects were monitored weekly and liver function tests biweekly.

RESULTS

Data from 45 patients were analyzed. Using random regression analysis, significant improvement was noted in all three gambling symptom measures: patient-rated Clinical Global Impression, p <.001; clinician-rated CGI, p <.001; Gambling Symptom Rating Scale, p <.019. At study end, 75% of subjects taking naltrexone were much or very much improved on both the PE-CEI PT and the PG-CGI-MD, compared with only 24% of those on placebo. Elevated liver enzymes occurred in four subjects who were taking analgesics concurrently. Nausea was common during the first week of treatment.

CONCLUSIONS

Results suggest that naltrexone is effective in reducing the symptoms of pathologic gambling. Until further studies corroborate the present findings, our report should be interpreted cautiously.

Variable numbers of TTC repeats in Mycobacterium leprae DNA from leprosy patients and use in strain differentiation

Strain differentiation of Mycobacterium leprae would be of great value for epidemiological investigation to identify the infectious sources of leprosy, to understand transmission patterns, and to distinguish between relapse and reinfection. From the M. leprae genome sequence database, TTC DNA repeats were identified. Primer sets designed to amplify the region flanking TTC repeats revealed PCR products of different sizes, indicating that the number of repeats at each locus may be variable among M. leprae strains. The TTC repeats were not found in Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium marinum, or human tissues, which indicated their specificity to M. leprae. Sequence analysis of the TTC repeat region in each of the M. leprae strains showed a variation of 10 to 37 repeats. In the M. leprae strains of 34 multibacillary patients at Cebu, Philippines, M. leprae with 24 and 25 TTC repeats was most common, and this was followed by strains with 14, 15, 20, 21, and 28 repeats. This study thus indicates that there are variable numbers of TTC repeats in a noncoding region of M. leprae strains and that the TTC region may be useful for strain differentiation for epidemiological investigations of leprosy.

Reduction of hexavalent chromium collected on PVC filters

Chromium exists at various valences, including elemental, trivalent, and hexavalent chromium, and undergoes reduction-oxidation reactions in the environment. Since hexavalent chromium is known as a human carcinogen, it is most important to evaluate the oxidation-reduction characteristics of the hexavalent chromium species. Although hexavalent chromium can be reduced to trivalent state, the detailed information on this in workplace environments is limited. The purpose of this study was to investigate hexavalent chromium reduction in time in various conditions. A pilot chrome plating operation was prepared and operated in a laboratory for this study. There was evidence that the hexavalent chromium was reduced by time after mist generation. The percentage ratio (with 95% confidence intervals in parentheses) of hexavalent chromium to total chromium was almost 100% (99.1 approximately 102.3) immediately after mist generation, and was reduced to 87.4% (84.8 approximately 89.9) at 1 hour and 81.0% (78.3 approximately 83.5) at 2 hours, respectively. Another test indicated that hexavalent chromium collected on PVC filters was also reduced by time after sampling. Hexavalent chromium was reduced to 90.8% (88.2 approximately 93.3) at 2 hours after sampling. It also was found that hexavalent chromium was reduced during storage in air. It is recommended that air samples of hexavalent chromium be protected against reduction during storage.

The in vitro blood compatibility of poly(ethylene oxide)-grafted polyurethane/polystyrene interpenetrating polymer networks

Poly(ethylene oxide) (PEO)-grafted polyurethane (PU)/polystyrene (PS) interpenetrating polymer networks (IPNs) were synthesized. The effects of the mobile pendant PEO chains with their microphase separated structure on blood-compatibility were investigated. The morphology of both the fracture surface as well as the top surface indicate that the size of the dispersed domains of the PS-rich phase decreased as the grafting with the PEO was increased. The swelling ratio also decreased as the grafting with the PEO was increased. However, the dynamic contact angle and the interfacial energy between IPN surface and water decreased, due to the structural reorganization of the pendant PEO chains. PU/PS IPNs have an excellent mechanical property as compared with PU homopolymers. The adsorption of bovine plasma fibrinogen (BPF) onto the PU/PS IPNs and PU homopolymers was effectively suppressed by the PEO-grafting. In the platelet adhesion test, the amount of platelets adsorbed, activated, and/or coagulated upon the PEO-grafted PU/PS IPNs were reduced when compared to the ungrafted PU homopolymers.

Biochemical, molecular and physiological characterization of a new beta-casein variant detected in Korean cattle

There are seven known genetic variants of bovine beta-casein (beta-CN)--A1, A2, A3, B, C, D and E. In this study, we identified a new genetic variant (named beta-CN H) which migrates slower than the other variants in acidic starch gel electrophoresis. We confirmed through protein and DNA sequence analyses that the H variant differs at five residues from the A2 sequence: Arg25/Cys, Leu88/Ile, Gln117/Glu, Glu175/Gln and Gln195/Glu. Of these substitutions the 25th residue was contained in the casein phosphopeptide (CPP) region. In rats, calcium solubilizing effect of the CPP of bovine variant H was increased by approximately 23% compared with that of the CPP of non-H. Using extensive Korean Bos taurus pedigrees, we confirmed that beta-CN H was controlled by a codominant allele.

Increase in signal intensities on T1-weighted magnetic resonance images in asymptomatic manganese-exposed workers

OBJECTIVES

To clarify the clinical significance of increased signal intensities on T1 weighted magnetic resonance imaging (MRI) we performed a large-scale epidemiological study on asymptomatic manganese (Mn)-exposed workers with its focus on MRI.

METHODS

We randomly selected 121 male workers out of a total of 750 workers including Mn-exposed, non-exposed manual, and non-exposed clerical workers in the factories. We studied environmental and biological monitoring, neurological examination, and MRI.

RESULTS

The proportion of workers with increased signal intensities among the exposed, the non-exposed manual workers, and the non-exposed clerical workers was 46.1%, 18.8%, and 0%, respectively. Especially, 73.5% of the welders showed increased signal intensities. In no subject, were clinical signs of manganism observed. The pallidal index correlated with blood Mn concentration.

CONCLUSION

Increase in signal intensities on the T1-weighted image reflect recent exposure to Mn, but not necessarily manganism. At which increase of signal intensity, the progression of manganism from Mn exposure occurs, remains to be solved.

Idiopathic parkinsonism with superimposed manganese exposure: utility of positron emission tomography

It is difficult to distinguish manganism from idiopathic parkinsonism by clinical signs only. Case history and examination: A 48-year-old welder for over 10 years complained of masked face, right side (arm and leg) resting tremor, and bradykinesia for over one year. Magnetic resonance imaging (MRI) findings showed symmetrical high signal intensities in the globus pallidus on T1 weighted image. These intensities disappeared almost completely six months after cessation of exposure. 18F-6-fluorodopa (18F-dopa) positron emission tomography (PET) findings showed reduced 18F-dopa uptake in the left putamen, findings which appear in idiopathic parkinsonism. A PET study is necessary to distinguish manganism from idiopathic parkinsonism, especially in a working environment with elevated Mn concentrations, such as welding.

Biological control of fusarium wilt of cucumber by chitinolytic bacteria

ABSTRACT Two chitinolytic bacterial strains, Paenibacillus sp. 300 and Streptomyces sp. 385, suppressed Fusarium wilt of cucumber (Cucumis sativus) caused by Fusarium oxysporum f. sp. cucumerinum in nonsterile, soilless potting medium. A mixture of the two strains in a ratio of 1:1 or 4:1 gave significantly (P < 0.05) better control of the disease than each of the strains used individually or than mixtures in other ratios. Several formulations were tested, and a zeolite-based, chitosan-amended formulation (ZAC) provided the best protection against the disease. Dose-response studies indicated that the threshold dose of 6 g of formulation per kilogram of potting medium was required for significant (P < 0.001) suppression of the disease. This dose was optimum for maintaining high rhizosphere population densities of chitinolytic bacteria (log 8.1 to log 9.3 CFU/g dry weight of potting medium), which were required for the control of Fusarium wilt. The ZAC formulation was suppressive when added to pathogen-infested medium 15 days before planting cucumber seeds. The formulation also provided good control when stored for 6 months at room temperature or at 4 degrees C. Chitinase and beta-1,3-glucanase enzymes were produced when the strains were grown in the presence of colloidal chitin as the sole carbon source. Partial purification of the chitinases, followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and activity staining, revealed the presence of five bands with molecular masses of 65, 62, 59, 55, and 52 kDa in the case of Paenibacillus sp. 300; and three bands with molecular masses of 52, 38, and 33 kDa in the case of Streptomyces sp. 385. Incubation of cell walls of F. oxysporum f. sp. cucumerinum with partially purified enzyme fractions led to the release of N-acetyl-D-glucosamine (NAGA). NAGA content was considerably greater when pooled enzyme fractions (64 to 67) from Paenibacillus sp. were used, because they contained high beta-1,3-glucanase activity in addition to chitinase activity. Suppression of Fusarium wilt of cucumber by a combination of these two bacteria may involve the action of these hydrolytic enzymes.

Streptokinase secretion by Serratia marcescens signaled by the C-terminal 41 amino acid segment of metalloprotease

In order to investigate the secretion signal of Serratia marcescens metalloprotease (SMP) and examine the ability of the secretion signal to secrete foreign proteins, hybrid genes encoding the passenger-SMP C-terminal segments were constructed. As a passenger protein, streptokinase (SK) deprived of its signal peptide was used. Three kinds of SMP C-terminal segments containing 41, 80, or 220 amino acid residues were fused to the C-terminus of SK as secretion signals. The SK-SMP chimeric proteins containing 41 or 220 amino acid segments of the SMP C-terminus were secreted into the culture medium by the SMP transporter of S. marcescens. This result suggests that cytoplasmic SK is secreted into the external medium by the C-terminal segments of SMP and also shows that the smallest, 41 amino acid segment of the SMP C-terminus functions as a secretion signal of foreign proteins as well as SMP.

Nucleotide sequence of nucleocapsid protein (N) of Hantaan virus isolated from a Korean hemorrhagic fever patient

The nucleotide sequence of the nucleocapsid protein (N) coding region of a Hantaan virus strain (CFC94-2) isolated from a Korean Hemorrhagic Fever (KHF) patient was determined by sequencing a series of deletion mutants. Comparison of the N coding sequence of CFC94-2 to the sequence of the prototype of Hantaan virus, strain 76-118 reveals a 4.97% difference in the nucleotide sequence and a 1.6% difference in the deduced amino acid sequence. The rate of amino acid sequence variation in N protein of different Hantaan viruses (1.6%) is quite similar to that in G1 and G2 envelope proteins (1.7%). These results suggest that N protein may be under a similar selection pressure to G1 and G2 envelope proteins against host immune system.

The Leu-3 residue of Serratia marcescens metalloprotease inhibitor is important in inhibitory activity and binding with Serratia marcescens metalloprotease

Serratia marcescens metalloprotease inhibitor (SmaPI) is a proteinase inhibitor toward Serratia marcescens metalloprotease (SMP). In sequential deletion analysis of the N-terminal region of the SmaPI, SmaPIs starting at Ser-2 and Leu-3 residues, respectively, had nearly a full inhibitory activity toward SMP. However, SmaPI starting at Ala-4 residue showed severely decreased inhibitory activity. Furthermore, kinetic analysis demonstrated that SmaPI starting at the Ala-4 residue had an inhibition constant for SMP approximately fourfold higher than that of wild-type SmaPI. The interactions of Leu-3 with SMP contribute 0.73 kcal mol-1 to the overall stability of the SMP-SmaPI complex (8.44 kcal mol-1). To elucidate the detailed role of the Leu-3 residue in inhibitory activity of SmaPI, several site-directed mutations were introduced. The inhibitory activities of Leu-3 mutants in which the Leu-3 has been converted to Ala, Asp, Gly, Ile, Lys, Phe, or Pro were correlated with the hydrophobicities of substituted amino acids. About 0.3 kcal mol-1 is attributable to the side chain of the Leu-3 residue in the binding with SMP. From these results, it is suggested that (i) in contrast with the Erwinia chrysanthemi inhibitor, Gly-1 and Ser-2 of SmaPI are not critical and (ii) the hydrophobicity of Leu-3 may be important in its inhibitory activity and binding with SMP.

Revaluation on the types and pattern of distribution of sinusoidal fenestrations in the lobule of normal rat liver

BACKGROUND

There is a need to identify the existence of large fenestrations and to evaluate the type and pattern of the distribution of sinusoidal fenestrations in the hepatic lobule.

METHODS

The sinusoidal fenestrations in the rat liver lobule were investigated by scanning electron microscopy of perfusion-fixed specimens and by transmission electron microscopy of freeze-fracture replicas from immersion-fixed specimens. Ringer solution used for precleaning was equilibrated with 84%/16% O2/CO2 at 37 degrees C, and the perfusion pressure was maintained at 5-10 mmHg in the portal vein.

RESULTS

The fenestrations were recognized on the luminal surface of sinusoids on the basis of regional difference in size and distribution within the lobule and divided into three types: small, medium-sized, and large. The small fenestrations were numerous in each region. The number of medium-sized fenestrations was large in the pericentral and intermediate regions, while that of large fenestrations was predominant in the intermediate region. Based on the occurrence of fenestrations, the sinusoids were also divided into three types. The type I sinusoid mainly showed small fenestrations and was predominant in the periportal region. The type II sinusoid showed small and medium-sized fenestrations and was predominant in the pericentral region. The type III sinusoid showed all the types of fenestrations including large ones and was predominant in the intermediate region. The images showing dumbbell-shaped or irregularly shaped margins were observed between small or medium-sized fenestrations on the freeze-fracture replica.

CONCLUSIONS

1) The fenestrations are divided into three types according to the size and pattern of distribution within the lobule. 2) The sinusoids are also divided into three types based on the distribution pattern of each type of fenestrations. 3) The small fenestrations are evenly distributed throughout the entire lobule, while the medium-sized and large fenestrations show the regional difference within the lobule. 4) The large fenestrations exist as real structures of the endothelial lining cells of sinusoids and may result from the fusion of contiguous smaller ones.

Characterization of a metalloprotease inhibitor protein (SmaPI) of Serratia marcescens

As suggested by Y. Suh and M.J. Benedik (J. Bacteriol. 174: 2361-2366, 1992), Serratia marcescens ATCC 27117 produced very small amounts (0.8 U ml-1) of an inhibitor protein (SmaPI) that shows an inhibitory activity against extracellular 50-kDa metalloprotease (SMP) of S. marcescens and that is localized in the periplasm of cells at the optimal growth temperature of 25 degrees C. A recombinant S. marcescens harboring plasmid pSP2 encoding SMP and SmaPI genes produced 20 U of SmaPI ml-1 that is also localized in the periplasm of cells at 25 degrees C. However, a large amount of SmaPI (86 Uml-1) was extracellularly produced at the supraoptimal growth temperature 37 degrees C from the recombinant S. marcescens (pSP2). We purified SmaPI from the culture supernatant of S. marcescens (pSP2) grown at 37 degrees C, and some biochemical properties were characterized. SmaPI had a pI value of about 10.0 and was a monomeric protein with a molecular mass of 10,000. SmaPI was produced from a precursor SmaPI by cleavage of a signal peptide (26 amino acid residues). The inhibitor was stable in boiling water for up to 30 min. The thermostability of SmaPI can be attributed to its reversible denaturation. SmaPI inhibited SMP by formation of a noncovalent complex with a molar ratio of 1:1 and showed a high protease specificity, which inhibited only SMP among the various proteases we examined.

Purification and Characterization of a Maltotetraose-Forming Alkaline (alpha)-Amylase from an Alkalophilic Bacillus Strain, GM8901

An alkalophilic bacterium, Bacillus sp. strain GM8901, grown at pH 10.5 and 50(deg)C, produced five alkaline amylases in culture broth. At an early stage of the bacterial growth, amylase I (Amyl I) was produced initially and then, as cultivation progressed, four alkaline amylases, Amyl II, Amyl III, Amyl IV, and Amyl V, were produced from proteolytic degradation of Amyl I. A serine protease present in the culture medium was believed to be involved in Amyl I degradation. We purified Amyl I from the culture supernatant by ammonium sulfate precipitation, heparin-Sepharose CL-6B column chromatography, phenyl-Toyopearl column chromatography, and Mono Q HR5/5 high-performance liquid chromatography. The molecular weight of Amyl I was estimated to be about 97,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amyl I had an extremely high optimal pH of 11.0 to 12.0 and was stable in a broad pH range of 6.0 to 13.0. Amyl I had an optimal temperature of 60(deg)C and was stable up to 50(deg)C. Thermostability was increased in the presence of Ca(sup2+) and soluble starch. The enzyme required metal ions such as Ca(sup2+), Mg(sup2+), Cu(sup2+), Co(sup2+), Ag(sup+), Zn(sup2+), and Fe(sup2+) for its enzyme activity and was inhibited by 1 mM EDTA and 1 mM phenylmethylsulfonyl fluoride. According to the mode of action of Amyl I on starch, Amyl I was classified as an (alpha)- and exo-amylase. Amyl I produced maltotetraose predominantly from starch via intermediates such as maltohexaose and maltopentaose.

Antithrombogenicity of hydrophilic polyurethane-hydrophobic polystyrene IPNs. I. Synthesis and characterization

A series of interpenetrating polymer networks (IPNs) composed of hydrophilic polyurethane (PU) and hydrophobic polystyrene (PS) were prepared by the simultaneous polymerization method. The PU network was synthesized via the isocyanate-terminated PU prepolymer based on polyethylene glycol (PEG), a highly hydrophilic oligomer, and hexamethylene diisocyanate (HDI). The bulk and surface characteristics of these materials were analyzed by differential scanning calorimetry (DSC), tensile testing, scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA), and contact angle measurement. The PU/PS IPNs prepared in this study exhibited phase separated structures, which had dispersed PS domains in the continuous PU matrix, in both the bulk and surface showing two transition temperatures. The IPN containing 50 wt% of PS showed good mechanical properties. The enrichment of PU phase in the surface was revealed by SEM, ATR-FTIR, ESCA, and contact angle measurement.

Antithrombogenicity of hydrophilic polyurethane-hydrophobic polystyrene IPNs. II. In vitro and ex vivo studies

To investigate the effect of hydrophilic and hydrophobic surfaces with phase separated structure on their blood responses, interpenetrating polymer networks (IPNs) composed of hydrophilic polyurethane (PU) and hydrophobic polystyrene (PS) were prepared by simultaneous polymerization. In vitro protein adsorption, in vitro platelet adhesion, and ex vivo A-A shunt test were carried out to evaluate the blood compatibility of the PU/PS IPNs. The results of protein adsorption on the PU/PS IPN surfaces indicated that albumin preferentially adsorbed on the hydrophilic surface (PU), while fibrinogen preferentially adsorbed on the hydrophobic surface (PS). The PU/PS IPNs exhibited suppressive properties for both platelet adhesion and activation. The occlusion time of U50S50 IPN containing 50 wt% of PS was twice as long as that of the PU control (50 min), indicating enhanced blood compatibility, presumably due to the selective adsorption of plasma proteins and the suppression of the adhesion and activation of platelets.

Surface roughness evaluation via ultrasonic scanning

Despite extensive applications of ultrasonic waves to various nondestructive testing and evaluation of materials, scattering of focused ultrasonic waves due to surface roughness has not been fully investigated. This paper presents an analytical and experimental evaluation of surface roughness measurement using focused ultrasonic beams. The characteristics of focused ultrasonic waves are analyzed by using the impulse response method with a sine-modulated Gaussian pulse as source. First, the beam profile in the focal plane of the focused ultrasonic transducer is analyzed both numerically and experimentally. Second, peak amplitude distribution and reflected waveforms from a flat surface with various incident angles are analytically generated and compared with experimental results. Then, the peak amplitudes of the ultrasonic waves reflected from cusped surfaces which are easily found among machined surfaces are analyzed and compared with experimental data for the first time. The analysis shows good agreement between analytical and experimental results. The excellent correlation between the measurements using a profilometer and the proposed ultrasonic system demonstrates a good potential for surface roughness measurement by ultrasonic sensing.

Some observations on the morphological evidence for mechanism of the bile secretion

The morphological evidence of the intracellular route of bile secretion was investigated in the liver of goldfish (Carassius auratus) as revealed by electron microscopy. Smooth surfaced tubules or cisterns within or adjacent to the Golgi apparatus showed linear saccular forms and contained sparse particulate or cloudy materials of low electron density. The isolated vacuoles were restrictedly found between the Golgi apparatus and the intracellular bile canaliculus or hepatocytic side at the zone of transition. These vacuoles showed no reaction for acid phosphatase activity, and contained only a few cloudy materials similar to those found in the saccular tubules and within the bile canaliculus. Some of these vacuoles fused with the luminal cytolemmas of the bile canaliculus. Bases on these findings, it was assumed that these vacuoles are structures participating in transport and secretion of bile constituents and derive from the linearly sacculated tubules or cisterns in the Golgi zone. Duct cells showed no morphological evidence to suggest bile secretion.