A homopolymer stretch composed of variable numbers of cytidine residues in the terminal repeats of infectious laryngotracheitis virus

A homopolymer stretch composed of variable numbers of cytidine residues was found within the inverted terminal repeats of infectious laryngotracheitis virus (ILTV). A polymerase chain reaction procedure was developed to amplify a 750-bp fragment containing this homopolymer stretch. This fragment was then sequenced directly to determine the number of repeated cytidine residues in this homopolymer stretch, which could be used for strain differentiation. By this procedure, vaccine strains of tissue culture origin could be differentiated into two types: type I contains eight repeated cytidine residues, whereas type II contains 10 such residues. Vaccine strains of chicken embryo origin could also be divided into two types: type I contains mainly 11 repeated cytidine residues, whereas type II contains 15-21 such repeats. In comparison, two of the five field isolates examined contain 12-13 repeats; the other three field isolates contain 15-19 repeats, which were similar to the type II chicken-embryo-origin vaccines. The number of repeated cytidine residues described here could serve as a marker for the strain differentiation and epidemiologic study of ILTV.

Expression of major piroplasm protein (p33) of Theileria sergenti (Korean isolate) and its immunogenicity in guinea pigs

To investigate the development of a subunit vaccine against theileriosis in cattle, the DNA fragments encoding piroplasm surface protein (p33) of Theileria sergenti of a Korean isolate were expressed in baculoviruses. The expressed p33 was characterized by indirect fluorescent antibody (IFA) and western blotting analysis. The expression of p33 was mainly detected on the surface of infected Sf21 cells by IFA. The immunoblotting analysis revealed the presence of a same molecular weight protein band of p33. The antigenicity of expressed polypeptide was further examined through the inoculation of a guinea pig. The sera of guinea pigs immunized with p33 expressed cell lysate showed similar fluorescent antibody patterns and reacted with the same molecular weight protein of T. sergenti in immunoblotting analysis, thus indicating that this protein can be a promising candidate for a subunit vaccine in the future.

Molecular cloning and characterization of a cDNA encoding a transferrin homolog from Bombyx mori

We isolated a cDNA representing a message that was strongly induced by injection with E. coli in Bombyx mori. The 2160 bp cDNA has an open reading frame of 644 amino acids and the deduced product a predicted molecular mass of 71 kDa. The cDNA sequence shared high homology with the transferrins known so far, and its deduced peptide had unique features of transferrins, that is, sites of cystein residues and iron binding. We suggest that the B. mori transferrin plays an important role in the self-defense system.

Guanosine 5',3'-cyclic monophosphate enhances lipopolysaccharide-induced nitric oxide synthase expression in mixed glial cell cultures of rat

Primary mixed glial cell cultures treated with lipopolysaccharide (LPS; 1.0 microg/ml) showed biphasic increases of inducible nitric oxide synthase (iNOS) mRNA expression 6 h and 24-36 h after LPS treatment. Dibutyryl-guanosine 5',3'-cyclic monophosphate (db-cGMP; 1.0 mM) enhanced the second phase of the LPS-induced iNOS expression 24 and 30 h after LPS stimulation. KT5823 (1.0 microM), a protein kinase G (PKG) inhibitor, inhibited the LPS-induced iNOS expressions at 24 and 30 h and their enhancements caused by db-cGMP. In astrocyte-enriched cultures with reduced microglial contamination, the LPS-induced iNOS expression was decreased, though slightly enhanced by db-cGMP. These results suggest that cGMP/PKG signaling may be involved in the second phase of the LPS-induced glial iNOS expression and its upregulation, which are apparent in the presence of microglial cells.

Rapid degradation of PrxI and PrxII induced by silica in Rat2 cells

Peroxidases of the peroxiredoxin (Prx) family catalyze the reduction of H(2)O(2) and lipid peroxides. The effects of H(2)O(2), 12-O-tetradecanoylphorbol 13-acetate (TPA), and silica on the abundance of two cytosolic isoforms of Prx (PrxI and PrxII) were examined in Rat2 cells. TPA induces the production of reactive oxygen species (ROS) in various mammalian cell types, and silica induces the production of ROS in Rat2 cells. Whereas H(2)O(2) and TPA did not affect the concentration of PrxI or Prx II, silica triggered a rapid degradation of both Prx enzymes. Silica also induced degradation of the NF-kappaB inhibitor IkappaB-alpha. N-Acetylcysteine and diphenyleneiodonium, both of which inhibit the accumulation of intracellular ROS, each blocked silica-induced degradation of IkappaB-alpha but had no effect on that of the Prx enzymes, suggesting that ROS do not contribute to Prx proteolysis. The silica-induced degradation of Prx enzymes was also insensitive to the proteasome inhibitors MG132 and lactacystin, whereas IkappaB-alpha proteolysis was completely blocked by these inhibitors. Experiments with the Ca(2+) ionophore A23187 indicated that a Ca(2+)-dependent protease such as calpain might contribute substantially to silica-induced degradation of PrxII, but only moderately to that of PrxI. These results indicate that silica increases cellular oxidative stress not only by inducing ROS production, but also by triggering the degradation of Prx enzymes that are responsible for elimination of cellular ROS. Such aggravated oxidative stress might be important in the initial pathogenesis of silica-associated pulmonary diseases.

Protein kinase CKII interacts with and phosphorylates the SAG protein containing ring-H2 finger motif

To investigate the biological function of CKII, we have identified proteins that interact with the subunits of CKII using the yeast two-hybrid system. Here we report that SAG, an antioxidant protein containing Ring-H2 finger motif, is a cellular partner associating with the beta subunit of CKII. SAG does not interact with the alpha subunit of CKII. Analysis of SAG deletion mutants indicates that the Ring-H2 motif of SAG is necessary and sufficient for its binding to the beta subunit of CKII. Recombinant SAG can be phosphorylated by CKII in vitro, providing evidence that the beta subunit mediates the interaction of CKII enzyme with substrate proteins. Overlay experiment shows that SAG and the beta subunit of CKII associate directly in vitro and that CKII-mediated phosphorylation of SAG does not affect the interaction between SAG and the beta subunit of CKII. Northern blot analysis indicates that both SAG and the beta subunit of CKII were relatively rich in human heart, liver, skeletal muscle, and pancreas, but were detected in only trace amounts in brain, placenta, and lung. Our present results suggest that CKII may play a role in the regulation of SAG function.

Characterization of three isoforms of mammalian peroxiredoxin that reduce peroxides in the presence of thioredoxin

A peroxidase from yeast that reduces H2O2 with the use of electrons provided by thioredoxin (Trx) together with homologs from a wide variety of species constitute the peroxiredoxin (Prx) family of proteins. Twelve mammalian Prx members have been previously identified in association with various cellular functions apparently unrelated to peroxidase activity. These mammalian proteins have now been divided into three distinct types, Prx I, II, and III, on the basis of their deduced amino acid sequences and immunological reactivity. With the use of recombinant proteins, Prx I, II, and III have now been shown to possess peroxidase activity and to rely on Trx as a source of reducing equivalents. None of the three proteins exhibited peroxidase activity in the presence of glutaredoxin. All three enzymes showed similar kinetic properties: the Vmax was 6-13 micromol/min per mg at 37 degrees C, the Km for Trx was 3-6 microM, and the Km for H2O2 was < 20 microM. Immunoblot analysis of various rat tissues and cultured cells indicated that most cell types contain the three Prx isoforms, the sum of which amounts to approximately 1-10 microg per milligram of soluble protein. Prx I and II are cytosolic proteins, whereas Prx IlI is localized in mitochondria. These results suggest that, together with glutathione peroxidase and catalase, Prx enzymes likely play an important role in eliminating peroxides generated during metabolism as well as during stimulation of cell surface receptors.

Current status of peritoneal dialysis in Korea: efforts to achieve optimal outcome

Since its introduction in 1981, peritoneal dialysis (PD) has become firmly established as an effective mode of renal replacement therapy and serves an increasing patient population in Korea. The latest registry data indicate that about 3700 end-stage renal disease patients are maintained on chronic PD, representing 24.1% of the country's dialysis population. The majority (93.3%) of these patients are on continuous ambulatory peritoneal dialysis (CAPD) using the two-bag disconnect system, while only 3.3% are on automated PD. Under current renal reimbursement policies, most dialysis patients have to pay 20% of dialysis fees. Thus CAPD patients on 4 x 2-L daily exchanges pay about US$200 per month, not including medication and travel costs. Traditionally, most PD centers in Korea have used the "standard" prescription of 4 exchanges of 2 L of solution for most of their patients. A recent survey of 1467 patients who commenced CAPD in 1997 revealed that 84% of these patients were initially prescribed 4 x 2-L exchanges, while 12% were given a daily volume of 6 L. With this standard prescription, the percentages of Korean CAPD patients initially achieving the adequacy target of Kt/V urea > or = 2.0 and standardized creatinine clearance (SCCr) > or = 60 L/week/1.73 m2, were 74.4% and 82.1%, respectively. It is likely that, among current Korean CAPD patients, a much lower percentage will achieve the clearance targets compared to this initial outcome, but the precise data are not available. However, it is not clear whether the levels of small-solute clearance recommended for optimal PD outcomes, and proposed by the NKF-DOQI guidelines, will bring the expected benefits to Korean patients. Overall survival of Korean PD patients appears to be as good as, or even better than, that in most other countries. Recently, a single large PD center reported patient survival of 92.1%, 85.6%, 81.4%, and 67.6% at 1, 2, 3, and 5 years respectively. Other centers also reported similar outcomes. As in other countries, cardiovascular deaths predominate among Korean patients: death was due to cardiac causes in 29%, to vascular causes in 21%, and to infectious causes in 24%. Peritonitis is the most important barrier to prolonged use of CAPD in Korea, and more PD patients transfer to hemodialysis because of peritonitis than in other countries. To further reduce the morbidity and mortality of Korean PD patients, various control measures need to be implemented that can reduce or prevent peritonitis and other infectious complications. Also, to further improve long-term patient outcome, Korean nephrologists need to establish and practice optimal clearance targets in the chronic care of these patients.

Characterization of the murine gene encoding 1-Cys peroxiredoxin and identification of highly homologous genes

A new type of peroxiredoxin, named 1-Cys peroxiredoxin (1-Cys Prx), reduces hydrogen peroxide with the use of electrons from unidentified electron donor(s). We have isolated the mouse gene encoding 1-Cys Prx (CP-3) and shown that it is comprised of five exons and four introns. Analysis of 5' flanking regions revealed binding sequences of several putative transcription factors such as Sp1, Pit-1a, c-Jun, c-Myc and YY1. It is noticeable that several potential Sp1 binding sites assigned the -60 through -96bp from putative transcription initiation site. The gel shift assays showed that Sp1 and Pit-1a bind specifically to each binding site in 1-Cys Prx promoter. We also isolated two highly related genes such as CP-2 and CP-5. These genes are encoded by single exons, and show 85% of nucleotide sequence homology with the CP-3. The structural features of these genes suggest that they might be intronless genes derived from the CP-3 by the mechanism involving retrotransposition. In addition, our data suggest that they are inserted to a specific site of the mouse L1 repetitive element. The 1-Cys Prx was actively transcribed in a variety of adult tissues as well as in the developing embryos. These results suggest that only the 1-Cys Prx gene might be relevant for studying the function of the 1-Cys Prx in the murine system.

Up-regulation of clusterin (sulfated glycoprotein-2) in pancreatic islet cells upon streptozotocin injection to rats

Clusterin is a heterodimeric glycoprotein which has been shown to play important roles in programmed cell death and/or in tissue reorganization not only during embryonic development but also in damaged tissues. Recently, we reported the transient induction of clusterin in pancreatic endocrine cells during early developmental stages of islet formation. In the present study, we have investigated the expression of clusterin in pancreatic tissue of streptozotocin-treated rats which were undergoing extensive islet tissue reorganization due to degeneration of insulin beta cells. Clusterin was found in endocrine cells identified as glucagon-secreting alpha cells at the periphery of the islet. Using immunoelectron microscopy, clusterin-positive cells showed the typical ultrastructural features of pancreatic alpha cells. In addition, colocalization of clusterin and glucagon in the same secretory granules was shown by double immunogold labeling. These results imply that clusterin is a secretory molecule having endocrine and/or paracrine actions in parallel with glucagon. Further, we noted that clusterin expression was increased in pancreatic alpha cells during the process of beta cell death upon streptozotocin injection. The increase was significant as early as 1-3 h after streptozotocin treatment prior to any morphological alteration of islet beta cell and any manifestation of hyperglycemia. The expression of clusterin was steady-stately up-regulated during the process of islet reorganization caused by streptozotocin-induced cytotoxic injury. Therefore, we suggest that clusterin might be considered as a molecule induced by both embryonic development and drug-induced reorganization of the endocrine pancreas. Since clusterin expression is up-regulated in alpha cells, but not in beta cells undergoing degeneration, it may play a protective role against the cytotoxic insult.

Opioid receptor gene: cytokine response element and the effect of cytokines

Previous studies demonstrated that cytokines regulate opioid and opioid receptor gene expression in neuronal and immune cells. The gene sequence analysis of opioid receptors revealed that mu-, delta- and kappa-opioid receptor promoter regions contain potential cytokine response elements (NF-IL6 binding sites). It was postulated that the response elements present in opioid receptor promoter regions may have a role in the cytokine effects on opioid receptor gene expression through cis-trans interaction. The present study investigated whether cytokines have an effect on opioid receptor gene expression by cytokine-induced transcription factor, NF-IL6, using a number of immune cell lines which respond to cytokines. Further investigation was made to determine whether the potential cytokine response element DNA sequences on opioid receptor promoter region have functional significance which may be affected by the DNA context of the opioid receptor promoter in immune cell lines. Tandem repeats of conserved cytokine response elements of IL-6 gene fused to a heteropromoter SV40 were utilized as a positive control and expressed 2-fold increased promoter activity after cytokine stimulation. Transient transfection studies in time courses (24-72 h) and different dose treatments (100-500 U/ml for IL-6 and 50-200 U/ml for IL-1 alpha+beta) were also carried out to investigate the possibility that the upregulated gene expression may be transient or cytokine-dose-dependent. Our data demonstrated that there was no significant cytokine-stimulated opioid receptor gene expression in immune cells tested. In addition, the cytokine response elements (NF-IL6 binding sites) in opioid receptor genes are not functional. These results contradict the previous reports in which cytokines modulated the expression of opioid and opioid receptors in neuronal and immune cells. The possible reasons regarding the different results were discussed.

Functional studies on the interaction between human replication protein A and Xeroderma pigmentosum group A complementing protein (XPA)

The human replication protein A (RPA; also known as human single-stranded DNA binding protein, HSSB) is a multisubunit complex (70, 34 and 11 kDa subunits) involved in the three processes of DNA metabolism; replication, repair, recombination. We found that both 34 and 70 kDa subunits (p34 and p70, respectively), of RPA interacts with the Xeroderma pigmentosum group A complementing protein (XPA), a protein that specifically recognizes UV-damaged DNA. Our mutational analysis indicated that no particular domains of RPA p70 were essential for its interaction with XPA. We also examined the effect of this XPA-RPA interaction on in vitro simian virus 40 (SV40) DNA replication catalyzed by the crude extract and monopolymerase system. XPA inhibited SV40 DNA replication in vitro through its interaction with RPA. Taken together, these results suggest that there is a role for RPA in the regulation of DNA metabolism through its ability to modulate the interactions of proteins involved in the processes of DNA metabolism.

Bovine herpes virus expressing envelope protein (E2) of bovine viral diarrhea virus as a vaccine candidate

The gene encoding the envelope protein (E2) of bovine viral diarrhea virus (BVDV) was expressed under the thymidine kinase (TK) promoter of Korean bovine herpesvirus 1 (BHV-1) isolate. Thymidine kinase negative (TK-) BHV-1 recombinants expressing E2 of BVDV were constructed and the expression of E2 was identified by immunofluorescence and Western blotting. Compared to wild type BHV-1, the recombinant BHV-1 had a delayed cytopathogenic effect in cells. The immunogenicity of the recombinant BHV-1 was examined in guinea pigs and cattle. Although an increase in body temperature was detected for a few days, the inoculated cattle returned to normal temperature with the development of neutralizing antibodies to BVDV.

Risk factors influencing the decline of residual renal function in continuous ambulatory peritoneal dialysis patients

OBJECTIVE

To assess the nature of the decline in residual renal function (RRF) after the initiation of peritoneal dialysis, and to identify risk factors influencing the preservation of RRF.

DESIGN

A retrospective single-center study.

SETTING

Tertiary medical center.

PATIENTS

Eighty patients who were clinically stable and had been on continuous ambulatory peritoneal dialysis (CAPD) for a minimum of 6 months.

MAIN OUTCOME MEASURES

All subjects had at least three measurements of RRF, which was calculated as the average of creatinine clearance (Ccr) and urea clearance from a 24-hour urine collection. All measurements of RRF were plotted on a logarithmic scale and a linear scale against the duration of CAPD. Covariables used in the correlation analyses were age, sex, the presence of diabetes mellitus, mean blood pressure, mean diastolic blood pressure, hematocrit and Ccr at the start of peritoneal dialysis, peritoneal membrane transport characteristics by peritoneal equilibration test (PET), and the rate of peritonitis.

RESULTS

A significant correlation was found between CAPD duration and RRF decline represented on a logarithmic scale with a correlation coefficient (r) of 0.355 (p < 0.001). In contrast, on a linear scale, the correlation coefficient was only 0.273 (p < 0.01). By linear multiple regression analysis, the only independent risk factor for the decline of RRF was the rate of peritonitis (r = -0.446, p < 0.001).

CONCLUSION

These results suggest that RRF declines exponentially rather than linearly with time, and that the rate of peritonitis is an independent risk factor for the decline of RRF in CAPD patients.

Early rehabilitation program in postmastectomy patients: a prospective clinical trial

The purpose of this study was to determine whether 20 patients who received an early postmastectomy rehabilitation treatment program showed more improvement in range of shoulder motion and functional activities than 13 patients who received instruction for exercise only. Data were obtained at preoperatively, three days after operation, at discharge and at postdischarge one month for each patient on parameters such as range of motion of the ipsilateral shoulder joint, upper extremity circumferential measurements, as well as 10 elements of shoulder function. Postoperatively, both groups showed an increased range of motion of the shoulder joint and improved functional activities, but the group that received postoperative rehabilitation management had a better range of shoulder motion and less difficulty in five items for functional assessment. This study also showed that an early rehabilitation program did not increase postoperative complications. We concluded that an early rehabilitation program or intensive instruction program only by a well-trained physical therapist or physiatrist was beneficial to postmastectomy patients in regaining the function and range of shoulder motion, and significantly better in a rehabilitation group.

Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae

A yeast peroxidase that reduces H2O2 and alkyl hydroperoxides with the use of reducing equivalents provided by thioredoxin was identified previously and named thioredoxin peroxidase (TPx) [Chae, H. Z., Chung, S. J., and Rhee, S. G. (1994) J. Biol. Chem. 269, 27670-27678]. A second type thioredoxin-dependent peroxidase, named type II TPx, has now been purified from yeast, and several peptide sequences have been obtained. Using those sequences, the corresponding cDNA has been identified from the GenBank database. Comparison of the predicted sequence of 176 amino acids of type II TPx with that of the 195 residues of TPx, now renamed type I TPx, revealed no substantial homology except for a short segment preceding Cys62 of type II TPx. Kinetic characterization of the reactions catalyzed by type I and II TPxs revealed that type I preferentially reduces H2O2 rather than alkyl hydroperoxides, whereas type II shows the reverse specificity. Type II TPx contains three cysteine residues at positions 31, 62, and 120. Experiments with mutant proteins in which these three cysteine residues were replaced individually with serine suggest that Cys62-SH constitutes the site of oxidation by peroxides and that the oxidized Cys62 reacts with the Cys120-SH group of another type II TPx molecule to form an intermolecular disulfide linkage. The formed disulfide can then be reduced by thioredoxin, but not by glutathione. Thus, type II TPx mutants lacking Cys62 or Cys120 showed no detectable TPx activity, whereas mutation of Cys31 had no effect on TPx activity. An antioxidant function of type II TPx in intact cells was demonstrated by the observation that Escherichia coli cells overexpressing wild-type protein were less sensitive to inhibition of growth by alkyl hydroperoxides than were control cells or cells overexpressing the mutant protein lacking Cys62.

Antibody reaction of human anti-Toxoplasma gondii positive and negative sera with Neospora caninum antigens

Anti-Neospora caninum antibody was detected in anti-Toxoplasma gondii positive and negative human sera by ELISA, western blot and immunofluorescence assay (IFA). Twelve cases out of 172 (6.7%) Toxoplasma-positive sera cross-reacted with both T. gondii and N. caninum antigens, and one out of 110 Toxoplasma-negative sera reacted with N. caninum antigen by ELISA. By western blot, all 12 sera reacted with T. gondii antigens with various banding patterns but specifically at 30 kDa (SAG1) and 22 kDa (SAG2) bands. With N. caninum antigen, the number of reactive bands was reduced, however a 43 kDa band reacted in three cases in Toxoplasma-positive sera in addition to one in Toxoplasma-negative control sera. All sera of the Toxoplasma-positive group labeled surface membrane of T. gondii, but reacted differently with N. caninum. Fluorescence was detected in surface membrane, subcellular organelles, or both in N. caninum. And one case in the Toxoplasma-negative group also reacted with N. caninum strongly in subcellular organelles. This suggested that the antibody against N. caninum may be present in human sera although the positive rate was very low in this study. The possibility of human infection with N. caninum remains to be evaluated further.

Radiological findings in myxoid liposarcoma of the anterior mediastinum

CT and MR findings of a rare myxoid liposarcoma involving the anterior mediastinum are reported. The mass was a low density lesion with calcific septations and some peripheral frond-like enhancement on CT. MRI showed heterogeneous intermediate to high signal intensity on T1 weighted images and high signal intensity on T2 weighted images. The signal of the mass was not suppressed on fat suppressed images.

Serum C-reactive protein: a predictor of mortality in continuous ambulatory peritoneal dialysis patients

OBJECTIVE

To evaluate the predictive value of a single baseline serum C-reactive protein (sCRP) as a marker of mortality in continuous ambulatory peritoneal dialysis (CAPD) patients.

DESIGN

A review of prospectively collected data in a 2-year follow-up study.

SETTING

Tertiary medical center.

PATIENTS

The study included 106 patients who were stable and had been on CAPD for a minimum of 3 months.

MAIN OUTCOME MEASURES

Patient survival rate was the main outcome measure of this study. Other outcome measures were technique survival rate, peritonitis rate, and hospitalized days. Covariables used in the survival analysis were age, sex, the presence of cardiovascular disease or diabetes mellitus, sCRP, serum albumin, hematocrit, cholesterol, HDL-cholesterol, malnutrition by subjective global assessment (SGA), weekly Kt/V urea, and weekly standardized creatinine clearance (SCCr).

RESULTS

The 2-year patient survival rate was significantly lower in the increased sCRP group than in the normal sCRP group (66.7% vs 94.1%, p = 0.001), although there was no significant difference in technique failure, peritonitis rate, and hospitalized days between the two groups. By Cox proportional hazards analysis, independent predictors of mortality were: cardiovascular disease (relative risk, RR = 8.96, p < 0.005); increased sCRP level (RR = 1.19, p < 0.05); and high hematocrit (RR = 1.18, p < 0.05).

CONCLUSION

Serum CRP at enrollment is an independent predictor of 2-year patient survival in CAPD patients.

Transient expression of clusterin (sulfated glycoprotein-2) during development of rat pancreas

Clusterin has been known to play important roles not only in remodeling damaged tissues, but also in tissue reorganization during embryonic development. In the present study, we have investigated the expression of clusterin in the endocrine pancreas during embryonic development. Although a weak immunoreaction was detected in some pancreatic primordial cells at day 14 of gestation, distinct clusterin expression was identified by immunocytochemistry and Northern blot analysis at the 16th day of gestation. Clusterin-producing cells, which corresponded to insulin-containing cells, accounted for the major portion of the developing islet of Langerhans up to 18 days of gestation. Thereafter, clusterin-producing cells display similar distribution and morphological features to glucagon-producing cells. Clusterin expressed in the pancreas was shown by Western blot analysis to be a disulfide-linked heterodimer of 70 kDa with an alpha-subunit of 32 kDa. During early developmental stages, however, we found that proteolytic internal cleavage of the clusterin molecule occurred from the 18th day of gestation. Only one 70 kDa band on the 16th day and two bands (32 kDa and 70 kDa) on the 18th day of gestation were detected by Western blot analysis even in reducing conditions, while only a single 32 kDa band was detected on the second day after birth. The levels of clusterin mRNA in the pancreas transiently increased from the 16th day of gestation to the second day after birth, during the period when active cellular reorganization takes place to form the classic cellular features of the islet. Among various tissue (kidney, brain, liver, heart, lung and pancreas) the levels of clusterin mRNA were the highest in the pancreas from the 18th day of gestation to the second day after birth. In contrast, the lowest expression was observed in adult pancreatic tissue. The higher expression of clusterin in developing pancreas must indicate its involvement in tissue organization during development.

Interleukin-1 beta, -6 and interferon-gamma productions in patients undergoing continuous ambulatory peritoneal dialysis

In order to investigate cytokine productions in patients undergoing continuous ambulatory peritoneal dialysis (CAPD), we studied the production of interleukin (IL)-1 beta, -6 and interferon (IFN)-gamma by cultured peripheral blood mononuclear cells (PBMC) in peritonitis-free CAPD patients. The correlation of cytokine production with plasma parathyroid hormone (PTH) and albumin levels was also evaluated. While the release of IL-1 beta was not markedly different from controls release of IL-6 from 24-hour cultured PBMCs was significantly greater than that of controls, (Mean +/- S.D., IL-6: 2186.8 +/- 1217.9 pg/ml, vs 1516.3 +/- 767.9, p < 0.05). The addition of lipopolysaccharide (LPS, 10 micrograms/ml, significantly stimulated IL-1 beta and -6 production of PBMCs in CAPD patients and controls, compared to an unstimulated condition. The LPS-induced IL-1 beta production was also not markedly different from controls, whereas LPS-induced IL-6 production was significantly higher than controls (IL-6: 13,220.7 +/- 7177.4 vs 7411.4 +/- 1236.9, p < 0.05). However, the percentage increases of IL-6 production stimulated with LPS in CAPD patients were not significantly different from controls (p > 0.05). No difference of baseline IFN-gamma was detected between CAPD patients controls, but phytohemagglutinin (PHA, 10 micrograms/ml)-stimulated IFN-gamma release was significantly higher in CAPD patients than controls (2425.9 +/- 1565.0 pg/ml vs 1364.0 +/- 755.1, p < 0.05). There was no significant correlation between PTH and, IL-1 beta, serum albumin level and LPS-stimulated IL-6 production (r = 0.54, p < 0.05). In conclusion, CAPD seems to partly induce activation of PBMCs with an enhanced release of IL-6 and IFN-gamma, and CAPD patients with higher serum albumin levels tend to show higher IL-6 production in immune response.

Cloning and expression of a novel gene encoding a new antibacterial peptide from silkworm, Bombyx mori

We differentially screened a novel gene encoding a new antibacterial peptide from the immunized Bombyx mori cDNA library. The gene showed a similar structure to that of cecropin-family, encoding 59 amino acids including a putative leader peptide and mature peptide. The deduced peptide, named Enbocin, had conserved amino acid residues which have been known to play an important role in the antibacterial activities. Enbocin genomic sequence revealed that the transcription unit of Enbocin gene was about 1.2 kb, and the coding sequence was interrupted by an intron of 660 bases. Recombinant Enbocin, expressed under the control of the baculovirus polyhedrin promoter, demonstrated a broad range of antibacterial activities against gram positive and gram negative bacteria.

Crystallization and preliminary X-ray studies of hORF6, a novel human antioxidant enzyme

HORF6 is a member of the novel antioxidant enzyme family found in humans. A recombinant form of hORF6 expressed and purified from E. coli has been crystallized by the hanging-drop method using various PEG's as precipitating agents. HORF6 crystallizes in two different monoclinic space groups, P21 and C2. The P21 crystals have unit-cell dimensions of a = 47.85, b = 75.17, c = 63.30 A and beta = 110.21 degrees and contain two monomers per asymmetric unit, while the C2 crystals have unit-cell dimensions of a = 165.27, b = 95.44, c = 166.44 A and beta = 128.97 degrees and contain more than six monomers per asymmetric unit. The P21 crystals with the smaller unit cell diffract X-rays better and behave well for the X-ray analysis. A native data set from a single crystal of the P21 space group gas been collected to 2.0 A resolution.

Crystal structure of a novel human peroxidase enzyme at 2.0 A resolution

Hydrogen peroxide (H2O2) has been implicated recently as an intracellular messenger that affects cellular processes including protein phosphorylation, transcription and apoptosis. A set of novel peroxidases, named peroxiredoxins (Prx), regulate the intracellular concentration of H2O2 by reducing it in the presence of an appropriate electron donor. The crystal structure of a human Prx enzyme, hORF6, reveals that the protein contains two discrete domains and forms a dimer. The N-terminal domain has a thioredoxin fold and the C-terminal domain is used for dimerization. The active site cysteine (Cys 47), which exists as cysteine-sulfenic acid in the crystal, is located at the bottom of a relatively narrow pocket. The positively charged environment surrounding Cys 47 accounts for the peroxidase activity of the enzyme, which contains no redox cofactors.

Hepatitis G virus infection in hemodialysis and continuous ambulatory peritoneal dialysis patients

To determine the prevalence and clinical relevance of HGV infection in dialysis patients, we performed a cross-sectional study of 61 HD patients and 79 Continuous Ambulatory Peritoneal Dialysis (CAPD) patients. HGV-RNA was identified by reverse-transcription (RT) polymerase chain reaction (PCR) assay with primers from the 5'-untranslated region of the viral genome. The prevalence of HGV infection was similar in HD and CAPD patients (9.8% vs. 12.7%), while that of HCV infection was significantly higher in HD patients compared to CAPD patients (16.4% vs. 1.3%, p < 0.05). The mean age (49.2 +/- 13.4 vs. 46.7 +/- 13.0 years), male to female ratio (2.4:1 vs. 1.3:1), history of transfusion (62.3% vs. 49.4%), history of hepatitis (27.9% vs. 26.6%), mean ALT level during the previous 6 months (22.4 +/- 37.9 vs. 14.0 +/- 7.4 IU/L), and the prevalence of HBsAg (8.2% vs. 6.3%) showed no difference between HD and CAPD patients. In both HD and CAPD patients, the presence of HGV RNA was not related to age, sex, duration of dialysis, history of transfusion, history of hepatitis, or to the presence of HBV or HCV markers. There was no significant difference in the clinical and biochemical data between patients with isolated HGV infection (n = 12) and patients without viremia (n = 106). The clinical feature of patients coinfected with HGV and HBV (n = 2), or HGV and HCV (n = 2) seemed to be similar to those of patients with isolated HBV (n = 8) or HCV (n = 9) infection. In conclusion, the prevalence of HGV infection was not different between HD and CAPD patients, and HGV infections did not seem to be associated with clinically significant hepatitis. The routes of HGV transmission, other than transfusion or contamination during HD procedure, were suspected.

Characterization of a mammalian peroxiredoxin that contains one conserved cysteine

A new type of peroxidase enzyme, named thioredoxin peroxidase (TPx), that reduces H2O2 with the use of electrons from thioredoxin and contains two essential cysteines was recently identified. TPx homologs, termed peroxiredoxin (Prx), have also been identified and include several proteins, designated 1-Cys Prx, that contain only one conserved cysteine. Recombinant human 1-Cys Prx expressed in and purified from Escherichia coli has now been shown to reduce H2O2 with electrons provided by dithiothreitol. Furthermore, human 1-Cys Prx transiently expressed in NIH 3T3 cells was able to remove intracellular H2O2 generated in response either to the addition of exogenous H2O2 or to treatment with platelet-derived growth factor. The conserved Cys47-SH group was shown to be the site of oxidation by H2O2. Thus, mutation of Cys47 to serine abolished peroxidase activity. Moreover, the oxidized intermediate appears to be Cys-SOH. In contrast to TPx, in which one of the two conserved cysteines is oxidized to Cys-SOH and then immediately reacts with the second conserved cysteine of the second subunit of the enzyme homodimer to form an intermolecular disulfide, the Cys-SOH of 1-Cys Prx does not form a disulfide. Neither thioredoxin, which reduces the disulfide of TPx, nor glutathione, which reduces the Cys-SeOH of oxidized glutathione peroxidase, was able to reduce the Cys-SOH of 1-Cys Prx and consequently could not support peroxidase activity. Human 1-Cys Prx was previously shown to exhibit a low level of phospholipase A2 activity at an acidic pH; the enzyme was thus proposed to be lysosomal, and Ser32 was proposed to be critical for lipase function. However, the mutation of Ser32 or Cys47 has now been shown to have no effect on the lipase activity of 1-Cys Prx, which was also shown to be a cytosolic protein. Thus, the primary cellular function of 1-Cys Prx appears to be to reduce peroxides with the use of electrons provided by an as yet unidentified source; the enzyme therefore represents a new type of peroxidase.

Mammalian peroxiredoxin isoforms can reduce hydrogen peroxide generated in response to growth factors and tumor necrosis factor-alpha

Mammalian tissues express three immunologically distinct peroxiredoxin (Prx) proteins (Prx I, II, and III), which are the products of distinct genes. With the use of recombinant proteins Prx I, II, and III, all have now been shown to possess peroxidase activity and to rely on Trx as a source of reducing equivalents for the reduction of H2O2. Prx I and II are cytosolic proteins, whereas Prx III is localized in mitochondria. Transient overexpression of Prx I or II in cultured cells showed that they were able to eliminate the intracellular H2O2 generated in response to growth factors. Moreover, the activation of nuclear factor kappaB (NFkappaB) induced by extracellularly added H2O2 or tumor necrosis factor-alpha was blocked by overproduction of Prx II. These results suggest that, together with glutathione peroxidase and catalase, Prx enzymes likely play an important role in eliminating peroxides generated during metabolism. In addition, Prx I and II might participate in the signaling cascades of growth factors and tumor necrosis factor-alpha by regulating the intracellular concentration of H2O2.

Abnormal distribution of Fc gamma receptor type IIa polymorphisms in Korean patients with systemic lupus erythematosus

OBJECTIVE

Abnormal immune complex clearance is a feature of systemic lupus erythematosus (SLE). Polymorphisms of the Fc gamma receptor type IIa (Fc gammaRIIa) genes (the receptor binds IgG2 and IgG3) are important disease susceptibility factors in some populations. This study sought to determine the effects of these polymorphisms among Korean patients with SLE.

METHODS

Polymerase chain reaction of genomic DNA and allele-specific oligonucleotide hybridization were used to determine Fc gammaRIIa genotypes in Korean patients with SLE and healthy control subjects. Clinical manifestations were analyzed in each patient and correlated with the genotypes.

RESULTS

Among the 73 SLE patients, there was an abnormal distribution of Fc gammaRIIa alleles when compared with 64 controls: 11.0% of the SLE patients were homozygous for Fc gammaRIIa-H131 compared with 34.4% of the controls (odds ratio [OR] 0.20, 95% confidence interval [95% CI] 0.04-0.95, chi2 = 5.7, P = 0.01699). The allelic frequency of Fc gammaRIIa-H131 was significantly lower in the SLE patients than in the controls (49.3% versus 63.3%; P = 0.02019), and it was also significantly lower in lupus patients with nephritis compared with the normal population (OR 0.53, 95% CI 0.29-0.95, chi2 = 5.15, P = 0.02330), but was not significantly lower in lupus patients without nephritis (P = 0.13663 versus controls). Clinically, the level of proteinuria was significantly higher in the lupus nephritis patients who had R/R131 than in those who had H/H131 or R/H131.

CONCLUSION

An abnormal distribution of Fc gammaRIIa polymorphisms was associated with SLE in Korean patients. There was a significant decrease in the Fc gammaRIIa-H/H131 genotype and H131 allelic frequency in SLE patients, particularly in those with nephritis. This suggests that the H131 allele confers some protection from SLE in this population.

Characterization of a human alpha1-antitrypsin variant that is as stable as ovalbumin

The metastability of inhibitory serpins (serine proteinase inhibitors) is thought to play a key role in the facile conformational switch and the insertion of the reactive center loop into the central beta-sheet, A-sheet, during the formation of a stable complex between a serpin and its target proteinase. We have examined the folding and inhibitory activity of a very stable variant of human alpha1-antitrypsin, a prototype inhibitory serpin. A combination of seven stabilizing single amino acid substitutions of alpha1-antitrypsin, designated Multi-7, increased the midpoint of the unfolding transition to almost that of ovalbumin, a non-inhibitory but more stable serpin. Compared with the wild-type alpha1-antitrypsin, Multi-7 retarded the opening of A-sheet significantly, as revealed by the retarded unfolding and latency conversion of the native state. Surprisingly, Multi-7 alpha1-antitrypsin could form a stable complex with a target elastase with the same kinetic parameters and the stoichiometry of inhibition as the wild type, indicating that enhanced A-sheet closure conferred by Multi-7 does not affect the complex formation. It may be that the stability increase of Multi-7 alpha1-antitrypsin is not sufficient to influence the rate of loop insertion during the complex formation.

Thioredoxin peroxidase is a novel inhibitor of apoptosis with a mechanism distinct from that of Bcl-2

Thioredoxin peroxidase (TPx) is a member of a newly discovered family of proteins that are conserved from yeast to mammals and to which natural killer enhancing factor belongs. These proteins are antioxidants that function as peroxidases only when coupled to a sulfhydryl reducing system. The physiological function of TPx in cells is not yet known. Here we demonstrate that when the human TPx II, a member of this family, is stably overexpressed in Molt-4 leukemia cells, it protects from apoptosis induced by serum deprivation, ceramide, or etoposide. TPx II, like Bcl-2, is able to inhibit release of cytochrome c from mitochondria to cytosol, and it inhibits lipid peroxidation in cells. TPx II, unlike Bcl-2, could prevent hydrogen peroxide accumulation in cells, suggesting that it functions upstream of Bcl-2 in the protection from apoptosis and may be implicated as an endogenous regulator of apoptosis.

Impact of metabolic acidosis on serum albumin and other nutritional parameters in long-term CAPD patients

To evaluate the effects of metabolic acidosis on serum albumin and other nutritional parameters in long-term continuous ambulatory peritoneal dialysis (CAPD) patients, we undertook a retrospective study involving 106 CAPD patients who had monthly biochemical measurements and urea kinetic studies every 6 months for more than 2 years. The patients were divided into three groups according to their mean total CO2 (tCO2) level of the 2-year follow-up (Group I: mean tCO2 < 22 mmol/L; Group II: 22 mmol/L < or = tCO2 < 26 mmol/L; Group III: mean tCO2 > or = 26 mmol/L), and the clinical, biochemical, and urea kinetic data were compared between the three groups. The mean tCO2 in Groups I, II, and III were 20.62 +/- 1.2 mmol/L, 23.91 +/- 1.1 mmol/L, and 27.3 +/- 0.8 mmol/L, respectively. The percentage of body weight (Bwt) to ideal body weight (IBW) was significantly higher in Group I (113.1 +/- 15.3%) compared to Group II (103.5 +/- 11.5%) and Group III (98.7 +/- 8.0%) (p < 0.05), but the percentage of lean body mass (LBM) to Bwt was not different between the three groups. Compared to Group III, Group I had significantly higher blood urea nitrogen (BUN) (61.1 +/- 14.3 vs 46.1 +/- 7.2 mg/dL, p < 0.05), serum albumin (4.04 +/- 0.31 vs 3.75 +/- 0.39 g/dL, p < 0.05), and normalized protein equivalent to nitrogen appearance (NPNA) (1.02 +/- 0.21 vs 0.88 +/- 0.14 g/kg/day, p < 0.05), and more ultrafiltration volume (1.4 +/- 0.4 vs 1.0 +/- 0.3 L/day, p < 0.05), in spite of comparable dialysis dose and albumin loss into the dialysate. No differences were observed in the three groups in the changes of tCO2, Bwt/IBW, LBM/Bwt, BUN, and albumin from the baseline values after the 2-year follow-up. Using stepwise multiple regression analysis, NPNA, Bwt/IBW, and ultrafiltration volume were independent factors affecting mean tCO2 level. In conclusion, low tCO2 levels in long-term CAPD patients may reflect increased protein intake, and the mild to moderate degrees of metabolic acidosis may not affect the nutritional status of well-dialyzed CAPD patients.

Cloning and sequencing of the secY gene homolog from Mycobacterium bovis BCG

The complete nucleotide sequence of a 1,513 bp fragment of Mycobacterium bovis BCG containing the secY gene homolog and partial adk gene that encodes an adenylate kinase has been determined. The secY gene of BCG has an open reading frame of 441 amino acids with homology to the SecY protein family. Comparative analyses of the deduced amino acid sequence of additional partial ORF revealed strong similarity to the known adenylate kinases.

The effect of anti-hypertensive drugs on DNA synthesis and proliferation of cultured rat aortic smooth muscle cells

The aim of this study was to elucidate the effects of anti-hypertensive drugs, nifedipine, furosemide, hydrochlorothiazide, captopril, and atenolol on DNA synthesis and proliferation of cultured rat aortic smooth muscle cells induced by fetal calf serum. Aortic smooth muscle cells from Sprague-Dawley rats were isolated, cultured, and seeded in multi-well plates. When confluent, cells were cultured in a conditioned medium without fetal calf serum. After 72 hours, cells were cultured in the medium retaining 10% fetal calf serum with or without anti-hypertensive drugs by increasing the concentration between 10(-8) and 10(-4) M. DNA synthesis was assessed by [3H]-thymidine uptake and proliferation by cell numbers using a hemocytometer. Nifedipine at a concentration of 10(-5) M and 5 x 10(-5) M inhibited serum-induced DNA synthesis significantly by 50.8% and 86.6%, respectively (p < 0.05). The results of cell numbers paralleled those of 3H-thymidine incorporation. Serum-induced DNA synthesis was also reduced by 32.6% at the highest dose of furosemide (10(-4) M), but there was no statistical significance. Hydrochlorothiazide, captopril, and atenolol did not show anti-proliferative effect throughout any of the doses. In conclusion, among the various anti-hypertensive drugs, nifedipine seems to be most beneficial in view of its direct inhibitory effect on DNA synthesis and proliferation of smooth muscle cells, as well as for its anti-hypertensive effect.

[Cloning and sequencing of p33 in a Korean isolate of Theileria sergenti]

The gene encoding the 33 kDa piroplasm surface protein of Theileria sergenti isolated in Korea was cloned and the nucleotide sequence was determined by dideoxy chain termination method. The cloned gene corresponds to 869 bp encoding an open reading frame 283 amino acids. Comparison of the sequence between Korean and Japanese isolates showed 99.4% homology rate in the nucleotide sequence and 98.9% homology rate in the amino acid sequence.

[Rapid detection of Theileria sergenti by polymerase chain reaction]

Four separate pairs of oligonucleotide primers within the coding region in a T. sergenti 33-kDa surface protein gene were selected to detect T. sergenti by PCR. The specificity of PCR-amplified DNA was examined by digestion with restriction enzyme and Southern blot hybridization using T. sergenti p33 DNA probe. PCR appears to be specific for T. sergenti, without detectable signals from uninfected erythrocytes, uninfected bovine leukocytes and other hemoparasites, including A. marginale and B. ovata. Although 46 of 71 specimens (64.8%) from grazing cattle were microscopically positive, PCR in this study showed that 64 specimens (88.7%) were positive. Therefore, PCR proves a useful diagnostic tool for detecting T. sergenti-infected cattle. In addition, it is also revealed that PCR was significantly more sensitive than traditional microscopic examination using Giemsa's stain.

Management of chronic hypotony following trabeculectomy with mitomycin C

Chronic hypotony is marked by decreased vision and late-onset leaking bleb after filtration surgery using topical mitomycin C; to manage this condition we followed a three-step approach: first, intrableb autologous blood injection; second, surgical exploration and additional suturing of the scleral flap; third, excision of the cystic bleb and advancement of a fornical conjunctival flap. For the avascular flap cystic blebs of five patients. In three of the six eyes, there was no increase of intraocular pressure (IOP); two eyes showed massive hyphema and were mildly resistant to the injection of autologous blood, and in one, a leaking hole was seen in the bleb wall two days after the injection of blood. Two eyes of three in which blood injection had failed, and another, in which the bleb had spread over more than half the eyeball, and which was the patient's only sighted eye, underwent the second step of the procedure. The remaining leaking eye, in which blood injection had been complicated, and another, in which spontaneous leakage from a thin avascular bleb had occurred, were subjected to the third step. After each of the three approaches, IOP increased on average from 1.67 to 5.67 mmHg, from 2.33 to 11.33 mmHg, and from 1.5 to 7 mmHg, respectively; each approach successfully improved vision. Intrableb autologous blood injection is a simple procedure for the management of chronic overfiltration and a way of determining whether excessive filtration is occurring through the scleral flap, in which case additional suturing is required, or in another way. Depending on the status of the bleb, additional suturing or excision of the cystic bleb and advancement of the fornical conjunctival flap are useful modalities for the treatment of late-onset leaking filtration bleb.

Interlimb interaction and stabilization of contralateral leg in isokinetic knee evaluation

OBJECTIVE

To determine if peak torque (PT) production during isokinetic knee testing is affected by the stabilization and movement patterns of the contralateral leg.

DESIGN

Repeated measure design.

INTERVENTION AND MAIN OUTCOME MEASURE

Thirty subjects participated in comparing the force outputs in relation to the movement pattern of both legs. Another group of 45 subjects volunteered to perform five maximal isokinetic extension-flexion contractions in each of three different knee testing conditions: (1) without stabilization of the contralateral leg; (2) with a bar in front of the ankle joint of the contralateral leg; (3) with the contralateral leg strapped just above the level of the malleoli and the muscles of that leg induced reciprocally to perform isometric contractions with respect to the testing leg. PT was used to compare the strength of three different conditions.

RESULTS

Significantly greater PT was measured when the contralateral leg of the subject was fixed and induced to contract reciprocally.

CONCLUSION

More rigorous standardization of isokinetic strength testing procedures is needed due to differences in PT production of knee muscles according to the stabilization and movement pattern of the contralateral leg.

Complete sequence of the UPP gene encoding uracil phosphoribosyltransferase from Mycobacterium bovis BCG

The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.

Xanthogranulomatous cholecystitis: CT features with emphasis on differentiation from gallbladder carcinoma

PURPOSE

To evaluate the computed tomographic (CT) features of xanthogranulomatous cholecystitis (XGC) and to distinguish it from gallbladder carcinoma.

MATERIALS AND METHODS

Retrospective analysis was performed in 11 patients with XGC and 17 patients with gallbladder carcinoma in which the wall was thickened. The following CT features were analyzed: maximum wall thickness, intramural hypoattenuated nodules, mucosal line, patterns of wall thickening and enhancement, and the presence of stones. The changes outside the gallbladder were also compared.

RESULTS

The mean thickness of the gallbladder wall was 1.8 cm in patients with XGC and 2.1 cm in patients with gallbladder carcinoma. Intramural hypoattenuated nodules were seen in all patients with XGC but in only seven patients with gallbladder carcinoma (P = .008). The mucosal line was observed in nine patients with XGC and in six with gallbladder carcinoma (P = .02). The gallbladder wall was more diffusely thickened in patients with XGC (10 of 11 patients) than in patients with gallbladder carcinoma (seven of 17 patients) (P = .01). The occurrence of changes outside the gallbladder did not differ statistically significantly.

CONCLUSION

Because of a statistically significant overlap of CT features, only when intramural hypoattenuated nodules occupy a large area of the thickened gallbladder wall can the diagnosis of XGC be highly suggestive. The diagnosis of XGC at CT may indicate a less aggressive surgical approach.

Epidermal growth factor (EGF)-induced generation of hydrogen peroxide. Role in EGF receptor-mediated tyrosine phosphorylation

Recent evidence indicates that reactive oxygen species (ROS) may function as intracellular messengers in receptor signaling pathways. The possible role of ROS in epidermal growth factor (EGF) signaling was therefore investigated. Stimulation of A431 human epidermoid carcinoma cells with EGF resulted in a transient increase in the intracellular concentration of ROS, measured with the oxidation-sensitive fluorescent probe 2',7'-dichlorofluorescin diacetate and laser-scanning confocal microscopy. The predominant ROS produced appeared to be H2O2, because the EGF-induced increase in fluorescence was completely abolished by incorporation of catalase into the cells by electroporation. The elimination of H2O2 by catalase also inhibited the EGF-induced tyrosine phosphorylation of various cellular proteins including the EGF receptor and phospholipase C-gamma1. The dependence of H2O2 production on the intrinsic tyrosine kinase activity of the EGF receptor and the autophosphorylation sites located in its COOH-terminal tail was investigated. EGF failed to induce H2O2 generation in cells expressing a kinase-inactive EGF receptor. However, normal H2O2 generation was observed in cells expressing a mutant receptor from which the 126 COOH-terminal amino acids had been deleted to remove four (out of the total of five) autophosphorylation sites. These results suggest that EGF-induced H2O2 formation requires the kinase activity but probably not the autophosphorylation sites of the EGF receptor and that inhibition of protein tyrosine phosphatase activity by H2O2 may be required for EGF-induced protein tyrosine phosphorylation to be manifested.

The effects of high glucose concentration on angiotensin II- or transforming growth factor-beta-induced DNA synthesis, hypertrophy and collagen synthesis in cultured rat mesangial cells

Hyperglycemia is a principal characteristic of diabetes, and has an influence on many cellular functions. In order to investigate whether the intracellular signaling pathways inducing proliferation, hypertrophy and matrix synthesis of mesangial cells are altered in a diabetic environment, we evaluated the effects of a high concentration of extracellular glucose(25 mM; 450 mg/dl) on [3H]thymidine uptake, hypertrophy, and [3H]proline incorporation into a collagenase-sensitive protein, induced by angiotensin II(Ang II) or transforming growth factor(TGF)-beta, in cultured rat mesangial cells. The exposure to a high glucose concentration for 7 days significantly inhibited Ang II(10(-6) M)-induced [3H]thymidine uptake, compared to normal glucose concentration (5 mM)(M +/- SD., 1050 +/- 100 cpm/well vs 550 +/- 97, p < 0.05), and markedly prevented the inhibition of [3H]thymidine uptake by TGF-beta(1 ng/ml)(132 +/- 10 vs 340 +/- 67, p < 0.05). The administration of H-7(50 microM), a protein kinase C(PKC) inhibitor, did not reverse these effects of high glucose on [3H]thymidine uptake. On flow cytometric analysis of cell size, the mean cell size was significantly greater for the cells exposed to high glucose or treated with Ang II or TGF-beta, compared to that for the untreated cells. But the addition of Ang II or TGF-beta to the cells exposed to high glucose did not show further enlargement in size. The exposure to high glucose and the treatment with Ang II or TGF-beta significantly increased collagen synthesis, measured by [3H]proline incorporation. The Ang II -or TGF-beta-induced increase of [3H]proline incorporation did not show changes under high glucose culture condition, compared to normal glucose concentration(Ang II, 27880 +/- 3560 cpm vs 26978 +/- 2284, TGF-beta, 26559 +/- 3700 vs 25800 +/- 1660, p > 0.05). In conclusion, although the signaling pathway for DNA synthesis by Ang II or TGF-beta are influenced, possibly mediated by PKC-independent mechanism(s), the pathway inducing hypertrophy or collagen synthesis by both agents appears to be unchanged under the high extracellular glucose concentration in cultured rat mesangial cells.

Studies on bone markers and bone mineral density in patients with chronic renal failure

Renal osteodystrophy has become a frequent complication in patients with chronic renal failure (CRF), and various histologic forms such as high turnover, low turnover and mixed bone disease have been demonstrated. The only reliable method for distinguishing patients with high turnover from those with low turnover bone disease is bone histomorphometric study, but its clinical utility is restricted. Because of its invasive nature, efforts have been made to predict indirectly the type and severity of this metabolic bone disease by serum assays. In this cross-sectional study, we measured total and regional (head, arms, trunk, ribs, legs, spine and pelvis) bone mineral densities (BMD) by dual X-ray absorptiometry (DXA) in patients with variable degrees of CRF and correlated them with various bone markers. Decreased BMDs were detected in various skeletal sites (trunk and pelvis) in the patients' group. Total BMD Z score was lower in predialysis CRF patients than in the control subjects. Decreased BMD Z scores on weight-bearing bone were pronounced at L1 lumbar vertebra, femur trochanter, femur neck and Ward's triangle. Positive linear correlations were found between creatinine clearance and trunk, ribs, pelvis, and spine BMDs. There were inverse linear correlations between total BMD and total BMD Z score and alkaline phosphatase (AP), urine deoxypyridinoline (U-DPD) in the patients' group. There were no correlations between regional and total BMD, total BMD Z score and serum calcium, ionized calcium, and serum phosphate. There were inverse linear correlations between BUN, creatinine and bone-specific alkaline phosphatase in the predialysis CRF group. We evaluated the correlations between intact parathyroid hormone (i-PTH) and biochemical and other bone markers. There was statistically significant linear correlation between i-PTH and AP. Other bone markers have no significant correlations with i-PTH. Our results demonstrated that there is significant bone loss in patients with CRF before the start of dialysis and also regional variations of BMDs in predialysis CRF patients. DXA is a useful method for evaluating regional and total BMDs and provides information about diverse regional skeletal changes. AP, i-PTH and U-DPD can predict BMD of predialysis CRF patients.

The changes in muscle strength and relaxation time after a comprehensive rehabilitation program for patients with myotonic dystrophy

Myotonic dystrophy is a muscular disorder characterized by muscle weakness and myotonia. Myotonia manifests with abnormally slow relaxation after strong voluntary contraction of the muscles. In our previous study we reported that quinine sulfate provided therapeutic benefit to myotonia and a home exercise program based on muscle strengthening exercises improved muscle strength. The purpose of this study was to determine the effect of a multi-therapeutic program in patients with myotonic dystrophy. For six months, seven patients with myotonic dystrophy received heat therapy, were given psychologic intervention using relaxation techniques, were trained at home, and were given quinine sulfate. The changes in muscle strength and relaxation time between the post-six-months home exercise program combined with quinine sulfate therapy, and the post-six months multi-therapeutic program, were assessed from the first dorsal interossei, the elbow flexors, and the knee extensors. The results were as follows: 1) The mean muscle strength of the each of the three muscles after the six months multi-therapeutic program was improved but was not significant compared with the post-six-months home exercise program combined with quinine sulfate therapy. 2) The mean relaxation time of each of the three muscles after the six months multi-therapeutic program was significantly reduced compared with the home exercise program combined with quinine sulfate therapy. In conclusion, the multi-therapeutic program undertaken in this study was the better program for the patients with myotonic dystrophy.

Removal of hydrogen peroxide by thiol-specific antioxidant enzyme (TSA) is involved with its antioxidant properties. TSA possesses thiol peroxidase activity

The thiol-specific antioxidant protein (TSA) protects glutamine synthetase from inactivation by a metal-catalyzed oxidation (MCO) system comprised of dithiothreitol (DTT)/Fe3+/O2 but not by the ascorbate/Fe3+/O2 MCO system. The removal of sulfur-centered radicals or H2O2 has been proposed as the protective mechanism of TSA. Like catalase, TSA prevents the initiation of the rapid O2 uptake phase during MCO of DTT but causes only partial inhibition when added after the reaction is well into the propagation phase. Stoichiometric studies showed that the antioxidant property of TSA is, at least in part, due to its ability to catalyze the destruction of H2O2 by the overall reaction 2 RSH + H2O2 --> RSSR + H2O. Results of kinetic studies demonstrate that the removal of H2O2 by TSA correlates with its ability to protect glutamine synthetase from inactivation. In the presence of thioredoxin, TSA is more active, whereas C170S (an active mutant of TSA in which cysteine 170 was replaced by a serine) and open reading frame 6 (a human antioxidant protein homologous to TSA with only one conserved cysteine residue) are only slightly affected. The thiol specificity of the protective activity of TSA derives from the fact that the oxidized form of TSA can be converted back to its sulfhydryl form by treatment with thiols but not by ascorbate.