[Ambulatory blood pressure monitoring in hypertensive CAPD patients]

The periodic structure of 24-hour blood pressure variation(circadian rhythm of blood pressure by ambulatory blood pressure monitoring(ABPM) in hypertensive CAPD patients was investigated by a new method of analysis based upon the maximum entropy method(MEM). In addition, this method allows the adequacy of antihypertensive therapies to be evaluated in such patients. The results were as follows; 1) The frequency of non-dipper type hypertension was 88%(36/41 cases), and the remaining 12% (5/41) were dipper type hypertension patients. The rise in morning blood pressure(morning surge: MS) was noted in 64% of the former. 2) Night time systolic blood pressure(182 +/- 22 mmHg, n = 36) was higher in patients with non-dipper type hypertension than in those with the dipper type(151 +/- 17 mmHg, n = 5, p < 0.01). 3) The standardized level of systolic blood pressure(SLSBP) calculated by MEM analysis in patients with non-dipper type hypertension(177 +/- 7 mmHg) was comparable with that in those with dipper type hypertension(168 +/- 13 mmHg, ns). 4) Treatment with long-acting Ca antagonist alone significantly reduced both SLSBP and the area over the SLSBP from 188 +/- 18 mmHg to 160 +/- 7 mmHg(p < 0.01, n = 8), and area over the SLSBP from 2,735 +/- 340 mmHg.hr to 1,945 +/- 298 mmHg.hr(p < 0.01, n = 8). 5) In addition to long-acting Ca antagonist, administration of alpha 1-blocker given at bed time was significantly efficacious in reducing the rise in morning blood pressure, MS. The present study using MEM analysis of ABPM suggests that the blood pressure profile of hypertensive CAPD patients is characterized by a non-dipper type dominance and a frequent morning surge. Furthermore, the combined therapy with long-acting Ca antagonist and alpha 1-blocker was substantially effective both in reducing the overall blood pressure level, and in inhibiting the MS. This combined antihypertensive therapy may be potentially useful to prevent CAPD patients from the future development of cardiovascular complications.

Evidence for degradation of cytokines in the serum of patients with atopic dermatitis by calcium-dependent protease

Changes in the levels of cytokines in the circulating blood and skin have been reported in patients with atopic dermatitis (AD). We determined IFN-gamma, IL-2, IL-4, IL-5 and IL-10 in both the serum and plasma of 45 AD patients and 20 healthy donors. Since differences in the levels of these cytokines between serum and plasma were found, the roles of Ca2+ and proteolytic enzymes were examined. Levels of IL-2 and IL-10 were measured in citrated plasma to which various amounts of CaCl2, protease inhibitors, and proteases had been added. All cytokine determinations were carried out using a standard ELISA. The plasma levels of IFN-gamma, IL-2, and IL-5 were significantly elevated, but the serum levels of these cytokines were not significantly changed. The levels of IL-2 in the plasma of the AD patients averaged 4.25-fold higher than in the serum of the AD patients, and 2.5-fold higher than in the plasma of healthy controls (P < 0.001). CaCl2 produced a dose-dependent decrease in IL-2 and IL-10 in citrated plasma. The protease inhibitors PMSF, aprotinin and leupeptin produced a dose-dependent increase in measurable levels of IL-2 and IL-10 in plasma. A decrease in IL-2 levels was also seen in CaCl2-supplemented serum-free medium, and this was accentuated by the addition of the proteases thrombin, trypsin, chymotrypsin and elastase. These findings suggest that although significant changes in cytokine levels have been reported not to occur in circulating blood but have been reported to occur in the skin of AD patients both in vivo and in vitro, cytokines can indeed also be found to be elevated in circulating blood when assessed carefully by statistically valid methods. Further, it is suggested that during the preparation of serum, some circulating cytokines are degraded by calcium-dependent proteases, and that Ca2+ itself can also affect the measurement of cytokines. The measurement of circulating cytokines needs to be carefully reassessed.

Role of EspB in experimental human enteropathogenic Escherichia coli infection

Enteropathogenic Escherichia coli (EPEC), a leading cause of diarrhea among infants in developing countries, induces dramatic alterations in host cell architecture that depend on a type III secretion system. EspB, one of the proteins secreted and translocated to the host cytoplasm via this system, is required for numerous alterations in host cell structure and function. To determine the role of EspB in virulence, we conducted a randomized, double-blind trial comparing the ability of wild-type EPEC and an isogenic DeltaespB mutant strain to cause diarrhea in adult volunteers. Diarrhea developed in 9 of 10 volunteers who ingested the wild-type strain but in only 1 of 10 volunteers who ingested the DeltaespB mutant strain. Marked destruction of the microvillous brush border adjacent to adherent organisms was observed in a jejunal biopsy from a volunteer who ingested the wild-type strain but not from two volunteers who ingested the DeltaespB mutant strain. Humoral and cell-mediated immune responses to EPEC antigens were stronger among recipients of the wild-type strain. In addition, four of the volunteers who ingested the wild-type strain had lymphoproliferative responses to EspB. These results demonstrate that EspB is a critical virulence determinant of EPEC infections and suggest that EspB contributes to an immune response.

Serum CYFRA 21-1 in cervical cancer patients treated with radiation therapy

BACKGROUND

A fragment of cytokeratin 19, referred to as CYFRA 21-1, is abundant in the serum of many patients with malignant tumors and is recognized as one of the established tumor markers, especially for non-small-cell lung cancer. In this study, the clinical usefulness of CYFRA 21-1 was investigated in cervical cancer patients treated with radiation therapy with reference to squamous-cell-carcinoma-related antigen (SCC-Ag), a common tumor marker of cervical squamous cell carcinoma.

MATERIALS AND METHODS

The serum levels of CYFRA 21-1 and SCC-Ag of 50 patients with squamous cell carcinoma of the uterine cervix were measured before and after radiation therapy.

RESULTS

CYFRA 21-1 was positive in 52% of the patients. The incidence increased with the stage of the cancer, and post-treatment increases were a sign of disease progression. During radiation, serum levels of CYFRA 21-1 decreased significantly and reflected the radiation effect well. In addition, CYFRA 21-1 was negative in all patients without distant metastasis at the end of radiation therapy. Compared with SCC-Ag, patients were less often positive for CYFRA 21-1, but there was a statistically positive correlation between the two markers (correlation matrix=0.69).

CONCLUSIONS

CYFRA 21-1 can be used in monitoring the outcome of patients with squamous cell carcinoma of the uterine cervix. It may be particularly useful for patients without SCC-Ag.

Reduction of globotriaosylceramide in Fabry disease mice by substrate deprivation

We used a potent inhibitor of glucosylceramide synthase to test whether substrate deprivation could lower globotriaosylceramide levels in alpha-galactosidase A (alpha-gal A) knockout mice, a model of Fabry disease. C57BL/6 mice treated twice daily for 3 days with D-threo-1-ethylendioxyphenyl-2-palmitoylamino-3-pyrrolidi no-propanol (D-t-EtDO-P4) showed a concentration-dependent decrement in glucosylceramide levels in kidney, liver, and spleen. A single intraperitoneal injection of D-t-EtDO-P4 resulted in a 55% reduction in renal glucosylceramide, consistent with rapid renal glucosylceramide metabolism. A concentration-dependent decrement in renal and hepatic globotriaosylceramide levels was observed in alpha-Gal A(-) males treated for 4 weeks with D-t-EtDO-P4. When 8-week-old alpha-Gal A(-) males were treated for 8 weeks with 10 mg/kg twice daily, renal globotriaosylceramide fell to below starting levels, consistent with an alpha-galactosidase A-independent salvage pathway for globotriaosylceramide degradation. Complications observed with another glucosylceramide synthase inhibitor, N-butyldeoxynojirimycin, including weight loss and acellularity of lymphatic organs, were not observed with D-t-EtDO-P4. These data suggest that Fabry disease may be amenable to substrate deprivation therapy.

Antitachycardia burst pacing for pleomorphic reentrant ventricular tachycardias associated with non-coronary artery diseases: a morphology specific programming for ventricular tachycardias

To study the role of antitachycardia burst pacing in patients with reentrant pleomorphic ventricular tachycardia (VT) associated with non-coronary artery diseases, the efficacy of antitachycardia pacing and appropriate antitachycardia pacing cycle length were evaluated in each pleomorphic VT morphology of seven patients. Seven patients were included in this study. Clinically documented pleomorphic VTs were reproduced in an electrophysiologic study. For each VT, rapid ventricular pacing was attempted from the apex of the right ventricle at a cycle length which was 20 ms shorter than that of VT and repeated after a decrement of the cycle length in steps of 10 ms until the VT was terminated or accelerated. All 16 VTs could be entrained by the rapid pacing, and 13 of the 16 VTs (81%) were terminated, whereas pacing-induced acceleration was observed in the other 3 VTs of the 3 patients. VT cycle length (VTCL), block cycle length (BCL) which was defined as the longest VT interrupting paced cycle length, %BCL/VTCL and entrainment zone which was defined as VTCL minus BCL, varied in each VT morphology of each patient. In two patients, antitachycardia pacing was effective in all VT morphologies and the maximum difference of the %BCL/VTCL among the pleomorphic VTs was less than 10%. Thus, antitachycardia pacing seemed to be beneficial for these patients. In the other 5 patients, a difference of more than 10% in %BCL/VTCL was observed among the pleomorphic VT morphologies and/or at least one VT morphology showed pacing-induced acceleration. Compared to the 13 terminated VTs, three accelerated VTs had a wide entrainment zone [160 +/- 44 vs 90 +/- 48 ms, p < 0.04] and small %BCL/VTCL [61 +/- 6 vs 77 +/- 11%,p<0.03]. In pleomorphic VTs associated with non-coronary artery diseases, responses to rapid pacing was not uniform; VT might be terminable or accelerated even in the same patient. We need to pay close attention when programming antitachycardia pacing in patients with pleomorphic VT.

Culture in the presence of sugars increases activity of multi-drug efflux transporter on Haloferax volcanii

We found that when a growth medium contained glucose, wild-type cells of Haloferax volcanii were able to grow even in the presence of doxorubicin (DOX), an anti-cancer reagent, whereas they usually cannot grow in its presence. The reason was that cells grown in the presence of glucose (glucose-grown cells) showed high multi-drug efflux activity even though the growth medium contained no DOX or substrates of the transporter. This transporter was ATP-driven and the elevation of efflux activity was not due to an increase in intracellular ATP contents. The activity was increased not only by glucose but also by sugars that could be metabolized.

Segmented filamentous bacteria prevent colonization of enteropathogenic Escherichia coli O103 in rabbits

Despite their distribution in the intestines of many mammals, including man, segmented filamentous bacteria (SFB) have not been found in rabbits, nor has any function been identified for these uncultivable microbes. New Zealand White rabbits were infected with rabbit enteropathogenic Escherichia coli O103 (REPEC O103) derivatives, followed up clinically, and randomly killed 1-4 days after inoculation. Intestinal tissue samples were examined by electron and light microscopy to search for SFB and to evaluate REPEC O103 colonization. Twelve of 21 rabbits showed SFB colonization on ileal absorptive villi. The presence of SFB was correlated with lack of REPEC 0103 ileal colonization (P<.01) and disease. Rabbits without SFB were always colonized by this pathogen. SFB appear to inhibit intestinal colonization by REPEC O103 and thus protect against REPEC 0103 disease. SFB colonization in rabbits is also described for the first time.

[The current status and future applications of gene therapy and immunogene therapy for malignant lymphoma]

The present therapy for malignant lymphoma including stem cell transplantation, has been greatly developed. However, treatments still remain ineffective for many patients. Gene therapy is providing new strategies for the treatments of malignant lymphoma. There are three major approaches; 1) killing the tumor cell itself by introducing anti-sense genes against oncogene, tumor suppressor genes or drug-sensitive genes. 2) modifying the immune response by introducing genes that will trigger anti-tumor response or tumor specific genes to antigen presenting cell. 3) decreasing the sensitivity of hemopoietic cells by introducing drug resistance genes. We describe here the current and future applications of gene therapy for malignant lymphoma.

Acetylation at the N-terminus of actin strengthens weak interaction between actin and myosin

The N-terminus of all actins so far studied is acetylated. Although the pathways of acetylation have been well studied, its functional importance has been unclear. A negative charge cluster in the actin N-terminal region is shown to be important for the function of actomyosin. Acetylation at the N-terminus removes a positive charge and increases the amount of net negative charges in the N-terminal region. This may augment the role of the negative charge cluster. To examine this possibility, actin with a nonacetylated N-terminus (nonacetylated actin) was produced. The nonacetylated actin polymerized and depolymerized normally. In actin-activated heavy meromyosin ATPase assays, the nonacetylated actin showed higher K(app) without significantly changing V(max), compared with those of wild-type actin. This is in contrast to the effect of the N-terminal negative charge cluster, which increases V(max) without changing K(app). These results indicate that the acetylation at the N-terminus of actin strengthens weak actomyosin interaction.

Glycosphingolipid depletion in fabry disease lymphoblasts with potent inhibitors of glucosylceramide synthase

BACKGROUND

Fabry disease is an inherited X-linked disorder resulting in the loss of activity of the lysosomal hydrolase alpha-galactosidase A and causing the clinical manifestations of renal failure, cerebral vascular disease, and myocardial infarction. The phenotypic expression of this disorder is manifest by the accumulation of glycosphingolipids containing alpha-galactosyl linkages, most prominently globotriaosylceramide.

METHODS

Based on quantitative structure activity studies, we recently reported two newly designed glucosylceramide synthase inhibitors based on 1-phenyl-2-palmitoylamino-3-pyrrolidino-1-propanol (P4). These inhibitors, 4'-hydroxy-P4 and ethylenedioxy-P4, were evaluated for their ability to deplete globotriaosylceramide and other glucosylceramide-based lipids in Fabry lymphocytes and were compared with N-butyldeoxynojirimycin, another reported glucosylceramide synthase inhibitor.

RESULTS

Concentrations as low as 10 nmol/L of 4'-hydroxy-P4 and ethylenedioxy-P4 resulted in 70 and 80% depletion, respectively, of globotriaosylceramide, with maximal depletion occurring at three days of treatment. There was no impairment of cell growth. In contrast, N-butyldeoxynojirimycin only minimally lowered globotriaosylceramide levels, even at concentrations as high as 10 micromol/L. Globotriaosylceramide depletion was confirmed by the loss of binding of FITC-conjugated verotoxin B subunit to the lymphoblasts.

CONCLUSIONS

These findings suggest that selective glucosylceramide synthase inhibitors are highly effective in the depletion of globotriaosylceramide from Fabry cell lines. We suggest that these compounds have potential therapeutic utility in the treatment of Fabry disease.

Microbial demetallization of crude oil: Nickel protoporphyrin disodium as a model organo-metallic substrate

A soil isolate designated as YA-1 strain was selected for its ability to degrade nickel protoporphyrin disodium (NiPPDS). The strain was capable of utilizing NiPPDS as the sole source of carbon. This strain, a gram-negative aerobic rod, was identified as Pseudomonas azelaica YA-1 based on the result of its 16S rRNA analysis. Product analyses by HPLC showed that this strain can decompose the porphyrin ring to which a metal ion is bound. However, the use of whole bacterial cells cannot result in extensive NiPPDS degradation; therefore, the YA-1 enzyme was extracted and purified. This NiPPDS-degrading enzyme named as protoporphyrinase was purified from P. azelaica YA-1 by ammonium sulfate fractionation and sequential chromatographies using DEAE Toyopearl 650 M, CM Toyopearl 650 M and Biogel P-60 columns, with a yield of 11.3% based on the enzyme activity and an overall purification of 498-fold. The molecular weight of this enzyme is estimated to be 39,000 Da by SDS-PAGE and 34,000 Da by gel filtration. The optimum pH and temperature for the enzyme were 7.0 and 30 degrees C, respectively. The activity was stable at pH 2.0-11.0 and at temperatures below 50 degrees C. The enzyme activity was inactivated by ferric chloride, potassium ferricyanide, ZnCl2 and CdCl2.

The effect of phospholipase A2 on bacterial translocation in a cell culture model

The activity of phospholipase (PL)A2 is elevated in the intestinal epithelia of patients with inflammatory bowel disease (IBD). Recently, we reported that lysophosphatidylcholine (L-PC), the PLA2 hydrolysis product of phosphatidylcholine (PC), stimulates bacterial translocation (BT) in an enterocyte cell-culture model. These two observations stimulated us to examine the effects of extracellular PLA2 on intestinal epithelial permeability. Human Caco-2 enterocytes were grown to confluence on porous filters in the apical chamber of a two-chamber cell-culture system. Monolayer integrity and tight-junction permeability were measured by dextran blue (DB) permeability and transepithelial electric resistance (TEER). Monolayers were treated with PC, L-PC, or PLA2 with and without PC. The magnitude of BT was determined 2 h after treatment by adding Escherichia coli to the apical chamber followed by quantitatively culturing basal chamber samples. Thin-layer chromatography (TLC) was utilized to verify PLA2 hydrolysis of PC to L-PC. Statistical analysis was performed by one-way analysis of variance. The magnitude of BT across monolayers pretreated with PLA2 + PC significantly increased compared to either PC or PLA2 (6.83 +/- 0.069, 2.41 +/- 0.46, and 3.06 +/- 1.14 log10 colony forming units/ml, respectively, P < 0.05). Absence of DB-permeability in any group confirmed monolayer integrity. TLC of PL samples harvested from the apical monolayer surface confirmed PC hydrolysis. PLA2 mediates hydrolysis of PC to L-PC when both are applied to the apical surface of cultured enterocyte monolayers, resulting in increased BT and increased TEER with no damage to monolayer integrity. These observations may have implications in the pathogenesis and treatment strategies for IBD.

In vivo interactions of rabbit enteropathogenic Escherichia coli O103 with its host: an electron microscopic and histopathologic study

A family of human and animal pathogens, including enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC), trigger formation of 'attaching and effacing' lesions on cultured and intestinal epithelial surfaces. However, our understanding of these events in vivo is incomplete. To further study these interactions in a natural infection model, weaned rabbits were infected with rabbit enteropathogenic E. coli O103 (REPEC O103), followed clinically, and infected tissues were evaluated by electron and light microscopy. Of the 36 rabbits challenged, morbidity and mortality were 65 and 23%, respectively. Twenty-four hours after infection, expression of fimbriae-like organelles was observed on the bacterial surface. Microvilli of ileal Peyer's patches (PP) became disorganized, and intestinal mucus secretion increased which coincided with intraluminal binding of the pathogen in the proximal colon. Forty-eight hours after infection, there was conspicuous lack of fimbriae-like organelle expression, while bacterial adherence preferentially occurred at the domed villi of PP. Seventy-two hours after infection, broad morphological heterogeneity was noted within pedestals beneath attached bacteria, including extended pseudopods. We conclude that REPEC O103 express surface organelles during initial exposure to the host, that the initial target sites of adherence are the domed villi of ileal PP, and that increased mucus secretion occurs during REPEC O103 infection. As well, extended pseudopod formation was demonstrated in vivo.

Induction of apoptosis in metastatic foci from human gastric cancer xenografts in nude mice and reduction of circulating tumor cells in blood by 5-FU and 1-hexylcarbamoyl-5-fluorouracil

Antimetastatic effects of 5-FU and its derivative, 1-hexylcarbamoyl-5-fluorouracil (HCFU) on human gastric cancer micrometastasis and their mode of action were evaluated, using a spontaneous lung metastasis model (HY-1) in nude mice. Metastases were first detected in the lung from 4 weeks after subcutaneous transplantation, growing intravascularly and forming micrometastases at 100% incidence by 6 weeks after implantation. Lung metastasis in mice bearing subcutaneous tumors was significantly inhibited by HCFU at doses of 100-150 mg kg(-1) day(-1) without severe toxic side-effects, when orally administered three times per week either from week 4 or week 6 to 9 weeks after implantation. Spontaneous lung metastasis was also inhibited by the administration of 5-FU, but to lesser extent than with HCFU at equimolar low doses. Apoptosis within primary tumors and lung metastatic foci, as detected by the terminal-deoxynucleotidyltransferase-mediated dUTP nick-end labeling method, was found to be significantly enhanced by HCFU as well as 5-FU administration at doses of more than 100 mg kg(-1) day(-1) and 50 mg kg(-1) day(-1) respectively. However, proliferating activity of the metastatic foci, as evaluated by MIB-1 immunostaining, was not significantly suppressed by HCFU or 5-FU treatment. Furthermore, polymerase chain reaction analysis using human specific primers for the beta-globin gene, which proved to be capable of detecting 10 tumor cells/ml mouse blood, revealed that circulating tumor cells in the peripheral blood of mice bearing primary tumors were reduced by HCFU or 5-FU administration. These results indicate that circulating tumor cells in blood and micrometastases in the lung are sensitive to these chemotherapeutic agents, and suggest that the anti-metastatic effect of these agents is mediated, at least in part, by enhanced apoptosis rather than by inhibition of cell proliferation.

Glucosylceramide synthase: assay and properties

Glucosylceramide synthesis is a key step in the formation of most mammalian glycosphingolipids. The expanding number of cellular functions that may be glycosphinolipid dependent and the identification of this glucosylceramide synthase as a potential therapeutic target for several sphingolipid storage disorders necessitate the availability of a reliable assay for glucosylceramide synthase. Coupled with the recent sequencing of this enzyme, the liposome-based assay utilizing a single extraction step should aid in the understanding of this critical early pathway in glycosphingolipid formation.

Significance of mesangial expression of alpha-smooth muscle actin in the progression of IgA nephropathy

To determine whether phenotypic modulation of mesangial and interstitial cells correlated with the long-term prognosis of IgA nephropathy (IgAN), we analyzed retrospectively 27 patients with IgAN whose creatinine clearance at the time of renal biopsy was normal. The patients were subdivided into two groups according to the course of renal function during follow-up. Thirteen patients maintained normal renal function for more than 15 years (stable group), and 14 progressed to end-stage renal disease (ESRD group). The score of mesangial cell cellularity in the ESRD group was significantly higher than in the stable group. Immunohistochemistry localized alpha-smooth muscle actin (alpha-SMA) in renal mesangial cells of approximately half these patients. Macrophages localized predominantly in the mesangial area in patients with mesangial expression of alpha-SMA, which was associated with the expression of macrophage-colony-stimulating factor. Noteworthily, the score of mesangial alpha-SMA expression and the incidence of patients with mesangial expression of alpha-SMA at the time of renal biopsy were markedly higher in the ESRD group than in the stable group. However, there was no significant difference in both the score of interstitial alpha-SMA expression and the incidence of patients with interstitial expression of alpha-SMA between these two groups. These results suggest that macrophages recruited into the mesangium may induce phenotypic modulation of mesangial cells and that mesangial alpha-SMA expression predicts a progressive decline in renal function in patients with IgAN.

The phase I/II clinical study of carbon ion therapy for cancer of the uterine cervix

PURPOSE

The phase I/II clinical study of carbon beam therapy was undertaken for 31 cases of advanced cervical cancer of stages IIIB and IVA from June 1995 to November 1997. The main purpose was to determine clinically useful fraction doses without severe acute reaction of normal tissues and to assess tumor control dose levels achievable without significant normal tissue toxicity.

PATIENTS AND METHODS

The treatment was given with four fixed fractions per week (24 fractions over 6 weeks) and was initiated with a fraction dose of 2.2 Gray equivalent (GyE), and the dose was increased as 2.4 GyE, 2.6 GyE, 2.8 GyE, and 3.0 GyE. Consequently, the total dose initiated was 52.8 GyE, to increase up to 72.0 GyE in 4.8-GyE increments in the dose-escalation fashion. Thirty patients with eligible advanced cervical cancers consisting of 27 squamous cell carcinomas and three adenocarcinomas were analyzed.

RESULTS

Acute response of normal tissues was less than with photon treatment until fraction doses of 2.8 GyE were administered, and patients finished treatment with comfortable conditions. Severe late complications occurred in the two patients who received more than 67.2 GyE. The 2-year cumulative survival rate and the local control rate of 27 patients with squamous cell carcinoma were 61.5% and 59.3%, respectively. According to stages, the 2-year survival rates of stage IIIB and IVA patients were 54.4% and 75.0%, respectively. The 2-year local control rates of stage IIIB and IVA patients were 52.6% and 75.0%, respectively.

DISCUSSION

These results indicated that the disease control seems to be relatively better for very advanced disease and with dose escalation treatment. Local control was not significantly correlated with total dose and tumor volume. The results of the present study, despite small numbers and short observation, suggest that an adequate fraction dose for pelvis fields is 2.8 to 3.0 GyE and that the carbon beam therapy might be advantageous for advanced cervical cancer.

Quantitation of hepatitis B virus genomic DNA by real-time detection PCR

Quantitation of hepatitis B virus (HBV) DNA in serum is a useful method for the monitoring of HBV replication. We attempted to develop a quantitative assay system for HBV DNA that is more sensitive, accurate, and reproducible than existing systems. We detected HBV DNA by real-time detection PCR (RTD-PCR) based on Taq Man chemistry. The efficacy of this assay was evaluated by quantitatively measuring sequential levels of synthetic DNA and DNA in clinical serum samples. The detection limit of this system was as few as 10 DNA copies/reaction. A linear standard curve was obtained between 10(1) and 10(8) DNA copies/reaction. The coefficient of variation for both intra- and interexperimental variability indicated remarkable reproducibility. This system detected HBV DNA in 100% of chronic hepatitis B patients tested and never detected HBV DNA in healthy volunteers who were negative for HBV markers. These observations suggest that RTD-PCR is an excellent candidate for a standard HBV quantification method.

A new Lp(a) assay that is unaffected by apo(a) size polymorphism

We developed sandwich ELISA methods in which anti-apo(a) kringle 4 type 5 through protease (K4 x 5-Pro) domain monoclonal antibody (clone: 203E2) is employed in each instance as the capture antibody and one of the three species of monoclonal antibody [Mab] (clones: 108B8, 202A9, 2B3) is used as the labeled antibody. Using serum containing apo(a) with 34 repeats of kringle 4 as the calibrator, a commercial kit using anti-Lp(a) polyclonal antibody (Pab) or anti-apo(a) Mab overestimated the Lp(a) concentration in samples containing apo(a) with more than 34 repeats of kringle 4 and underestimated the Lp(a) concentration in samples containing apo(a) with fewer than 34 repeats of kringle 4. Moreover, it was demonstrated that the ratios of commercial kit values to anti-apo(a) K4 x 5-Pro Mab-based method values increased as the size of apo(a) increased. The ratios of apo(a) K5 x Pro Mab-based method values to anti-apo(a) K4 x 5-Pro Mab-based method values, however, remained almost constant regardless of the size polymorphism. Thus, we suggest that apo(a) size heterogeneity can significantly affect Lp(a) measurement in the Lp(a) assay using anti-Lp(a) Pab. The novel Lp(a) assay method, using only anti-apo(a) K4 x 5-Pro Mab, is not subject to this phenomenon.

Enteropathogenic Escherichia coli translocated intimin receptor, Tir, requires a specific chaperone for stable secretion

Enteropathogenic Escherichia coli (EPEC) secretes several Esps (E. coli-secreted proteins) that are required for full virulence. Insertion of the bacterial protein Tir into the host epithelial cell membrane is facilitated by a type III secretion apparatus, and at least EspA and EspB are required for Tir translocation. An EPEC outer membrane protein, intimin, interacts with Tir on the host membrane to establish intimate attachment and formation of a pedestal-like structure. In this study, we identified a Tir chaperone, CesT, whose gene is located between tir and eae (which encodes intimin). A mutation in cesT abolished Tir secretion into culture supernatants and significantly decreased the amount of Tir in the bacterial cytoplasm. In contrast, this mutation did not affect the secretion of the Esp proteins. The level of tir mRNA was not affected by the cesT mutation, indicating that CesT acts at the post-transcriptional level. The cesT mutant could not induce host cytoskeletal rearrangements, and displayed the same phenotype as the tir mutant. Gel overlay and GST pulldown assays demonstrated that CesT specifically interacts with Tir, but not with other Esp proteins. Furthermore, by using a series of Tir deletion derivatives, we determined that the CesT binding domain is located within the first 100 amino-terminal residues of Tir, and that the pool of Tir in the bacterial cytoplasm was greatly reduced when this domain was disrupted. Interestingly, this domain was not sufficient for Tir secretion, and at least the first 200 residues of Tir were required for efficient secretion. Gel filtration studies showed that Tir-CesT forms a large multimeric complex. Collectively, these results indicate that CesT is a Tir chaperone that may act as an anti-degradation factor by specifically binding to its amino-terminus, forming a multimeric stabilized complex.