Soluble expression in Escherichia coli of murine endogenous retroviral transmembrane envelope protein having immunosuppressive activity

Recently, we cloned a fragment of the endogenous murine leukemia viral envelope gene from beta cell line (MIN6N8a) as a new autoantigen gene, whose product was reactive with nonobese diabetic (NOD) mice sera. As a result of determination of nucleotide sequence, this envelope protein had the CKS-17 peptide sequence having immunosuppressive activity. To investigate the role of our cloned transmembrane envelope protein in the pathogenesis of autoimmune insulin-dependent diabetes mellitus (IDDM) as an autoantigen or immunosuppressive modulator, a high amount of transmembrane envelope protein was essentially required. Therefore, the expression of our cloned retroviral transmembrane envelope gene was tried in Escherichia coli by a pET vector. However, the expression rate was very low (less than 2%) and most of the expressed protein was insoluble. To improve solubility, the hydrophobic transmembrane anchor domain of our envelope gene was deleted and then the expression of the hydrophilic transmembrane envelope protein was carried out by using the same pET expression system. The expressed protein was completely soluble and the expression yield was dramatically improved by around 25-fold increase. The hydrophilic transmembrane envelope protein was purified by one-step Ni-NTA affinity chromatography and then the fusion tag consisting of the six-histidine peptide and S peptide was removed by cleavage with enterokinase. The processed hydrophilic retroviral transmembrane envelope protein was still immune reactive with NOD sera and also showed immunosuppressive activity by down-regulating the Th1-type cytokine (interferon-gamma) and up-regulating the Th2-type cytokine (interleukin 10).

Developmental patterns of GalBeta1,3(4)GlcNAc alpha2,3-sialyltransferase (ST3Gal III) expression in the mouse: in situ hybridization using DIG-labeled RNA probes

Sialic acids are key determinants for biological processes, such as cell-cell interaction and differentiation. Sialyltransferases contribute to the diversity in carbohydrate structure through their attachment of sialic acid in various terminal positions on glycolipid and glycoprotein (N-linked and O-linked) carbohydrate groups. Galbeta 1,3(4)GlcNAc alpha2,3-sialyltransferase (ST3Gal III) is involved in the biosynthesis of sLe(x)and sLe(a) known as selectin ligands and tumor-associated carbohydrate structures. The appearance and differential distribution of ST3Gal III mRNA during mice embryogenesis [embryonic (E) days; E9, E11, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes coupled with alkaline phosphatase detection. On E9, all tissues were positive for ST3Gal III mRNA expression, whereas ST3Gal III mRNA on E11 was not detected throughout all tissues. On E13, ST3Gal III mRNA was expressed in different manner in various tissues. In this stage, ST3Gal III mRNA was positive only in the liver, pancreas and bladder. On E15, specific signal for ST3Gal III was detected in the liver, lung and forebrain. These results indicate that ST3GAI III is differently expressed at developmental stages of mice embryo, and this may be importantly related with regulation of organogenesis in mice.

Identification and characterization of an Escherichia coli invasion gene locus, ibeB, required for penetration of brain microvascular endothelial cells

Escherichia coli K1 is the most common gram-negative organism causing neonatal meningitis, but the mechanism by which E. coli K1 crosses the blood-brain barrier is incompletely understood. We have previously described the cloning and molecular characterization of a determinant, ibeA (also called ibe10), from the chromosome of an invasive cerebrospinal fluid isolate of E. coli K1 strain RS218 (O18:K1:H7). Here we report the identification of another chromosomal locus, ibeB, which allows RS218 to invade brain microvascular endothelial cells (BMEC). The noninvasive TnphoA mutant 7A-33 exhibited <1% the invasive ability of the parent strain in vitro in BMEC and was significantly less invasive in the central nervous system in the newborn rat model of hematogenous E. coli meningitis than the parent strain. The TnphoA insert with flanking sequences was cloned and sequenced. A 1,383-nucleotide open reading frame (ORF) encoding a 50-kDa protein was identified and termed ibeB. This ORF was found to be 97% identical to a gene encoding a 50-kDa hypothetical protein (p77211) and located in the 13-min region of the E. coli K-12 genome. However, no homology was observed between ibeB and other known invasion genes when DNA and protein databases in GenBank were searched. Like the TnphoA insertion mutant 7A-33, an isogenic ibeB deletion mutant (IB7D5) was unable to invade BMEC. A 7. 0-kb locus containing ibeB was isolated from a LambdaGEM-12 genomic library of E. coli RS218 and subcloned into a pBluescript KS vector (pKS7-7B). pKS7-7B was capable of completely restoring the BMEC invasion of the noninvasive TnphoA mutant 7A-33 and the ibeB deletion mutant IB7D5 to the level of the parent strain. More importantly, the ibeB deletion mutant IB7D5 was fully complemented by pFN476 carrying the ibeB ORF (pFN7C), indicating that ibeB is required for E. coli K1 invasion of BMEC. Taken together, these findings indicate that several E. coli determinants, including ibeA and ibeB, contribute to crossing of the blood-brain barrier.

Prenatal fragile X detection using cytoplasmic and nuclear-specific monoclonal antibodies

We have been carrying out studies aimed at improving prenatal detection of the fragile X chromosome/mutation. Our current protocol requires a turnaround time (TAT) of several days. In an attempt to reduce the TAT, we have turned to the use of monoclonal antibodies (mAbs). Monoclonal antibody 1A1 (provided by Dr. Mandel of INSERM) immunostaining was performed according to a modified three-step immunocytochemical procedure. We found that cytoplasmic staining intensities, using mAb 1A1/avidin biotinylated complex/diaminobenzidine, varied from light to heavy within each sample, with controls exhibiting a majority of heavily stained cells in both chorionic villus (CV) sample and amniotic fluid cultured cells. Using mAb 1A1 and a new nuclear-specific antibody, mAb 3F11, we found that CV cultured cells harboring the FMR1 full mutation could be distinguished from controls as early as 10 weeks of gestation in both male and female specimens. Western blot analysis showed that the antibodies have similar staining patterns but that mAb 3F11 has fewer background/nonspecific bands. Our results demonstrate that it is feasible to detect fragile X full mutations within one day after obtaining cells from CV specimens taken as early as 10 weeks of gestation.

Effectiveness of ranitidine bismuth citrate, clarithromycin, and metronidazole therapy for treating Helicobacter pylori

OBJECTIVE

There are limited data available from the United States on the effectiveness of ranitidine bismuth citrate (RBC) plus two antibiotics to treat Helicobacter pylori. Therefore, the following study was undertaken to evaluate RBC with two antibiotics, which have been used successfully in combination, to treat H. pylori.

METHODS

Adults with and without abdominal symptoms, who had never received H. pylori eradication therapy, were tested for the presence of H. pylori infection either by in-office rapid serology assays or histology. Positive subjects were administered the 13C-urea breath test. Subjects who had a positive urea breath test were then treated with RBC 400 mg b.i.d., clarithromycin 500 mg b.i.d., and metronidazole 500 mg b.i.d. for 10 days. Four to 6 wk after completing antibiotics all subjects were asked to return for a second urea breath test to assess treatment success.

RESULTS

Forty-seven of the 50 subjects enrolled into this study completed the antibiotic regimen and returned for a repeat urea breath test. Thirty-seven subjects were negative for H. pylori by urea breath test and 10 were positive, resulting in a 79% eradication rate. Seven subjects (14%) stopped their medication because of side effects. When analysis was performed on the 40 subjects who took > or = 80% of their medication (per-protocol), the eradication rate was 90%.

CONCLUSIONS

The combination of RBC with clarithromycin and metronidazole successfully treated H. pylori infection after only 10 days of therapy. The per-protocol eradication rate from this study was similar to that seen with Food and Drug Administration (FDA)-approved regimens. In conclusion, RBC plus clarithromycin and metronidazole should be considered as a first-line treatment regimen for H. pylori infection, and may only need to be taken for a period of 10 days, as opposed to 14 days for FDA-approved regimens.

Cocaine enhances brain endothelial adhesion molecules and leukocyte migration

Leukocyte infiltration of cerebral vessels in cocaine-associated vasculopathy suggests that cocaine may enhance leukocyte migration. We have investigated cocaine's effects on leukocyte adhesion in human brain microvascular endothelial cell (BMVEC) cultures and monocyte migration in an in vitro blood-brain barrier (BBB) model constructed with BMVEC and astrocytes. Cocaine (10(-5) to 10(-9) M) enhanced adhesion of monocytes and neutrophils to BMVEC. In the BBB model, cocaine (10(-4) to 10(-8) M) enhanced monocyte transmigration. Cocaine increased expression of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1, CD54), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (ELAM-1) on BMVEC. The peak effect on ICAM-1 expression was between 6 and 18 h after treatment. ICAM-1 was increased by cocaine in BMVEC, but not in human umbilical vein endothelial cells, and the enhancement was greater in a coculture of BMVEC with monocytes. ICAM-1 expression was enhanced by a transcriptional mechanism. Polymyxin B inhibited up-regulation of adhesion molecules by LPS but not by cocaine. In LPS-activated BMVEC/monocyte coculture, cocaine increased secretion of tumor necrosis factor-alpha and interleukin-6. Taken together, these findings indicate that cocaine enhances leukocyte migration across the cerebral vessel wall, in particular under inflammatory conditions, but the effects are variable in different individuals. Cocaine's effects are exerted through a cascade of augmented expression of inflammatory cytokines and endothelial adhesion molecules. These could underlie the cerebrovascular complications of cocaine abuse.

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

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

Immunomodulatory functions of hyaluronate in the LEW-to-F344 model of chronic cardiac allograft rejection

BACKGROUND

CD44 is an important leukocyte cell surface glycoprotein with diverse functions including cell adhesion, homing, migration, and activation.

METHODS

Because administration of the principal ligand of CD44, hyaluronate (HA), in soluble form, can inhibit CD44-HA interaction, we tested the effects of HA in vivo in an established model of chronic allograft rejection. Control F344 recipients of LEW hearts received either no treatment or low-dose cyclosporine (CsA) for 30 days from the day of transplantation. Experimental animals received 30 days of CsA in combination with 30 or 90 days of low molecular weight HA (LMW-HA).

RESULTS

CsA therapy alone resulted in approximately 40% long-term (>100 days) graft survival, whereas CsA + LMW-HA (30-day and 90-day protocols) significantly increased long-term graft survival to 60% and 92%, respectively. Light microscopy and immunohistology of CsA-treated and CsA + LMW-HA-treated grafts harvested at day 30 after transplantation demonstrated that LMW-HA + CsA therapy decreased mononuclear cell infiltration and afforded better preservation of myocardial architecture. In addition, LMW-HA + CsA-treated grafts exhibited decreased expression of interferon-gamma and the growth factors transforming growth factor-beta, platelet-derived growth factor, and fibrogenic growth factor-beta. Long-term surviving grafts were assessed for arteriosclerosis, the sine qua non of chronic rejection in this model. Using a standardized scoring system, significantly less arteriosclerosis was seen in grafts from LMW-HA + CsA-treated animals at 120 days after transplantation compared with CsA alone-treated grafts. This difference was not significant, however, in grafts harvested at >150 days.

CONCLUSION

This is the first report indicating that CD44-HA interactions play an important role in chronic allograft rejection.

Synthesis and hypoglycemic effect of chrysin derivatives

A series of 18 chrysin derivatives, prepared by alkylation and condensation, were fully characterized by NMR and other techniques and tested in vivo against the diabetes mellitus. Several modified compounds especially those with propyl, butyl, octyl and tolyl groups were found to have hypoglycemic effect on diabetec mice in spite of the fact that chrysin itself had inhibited insulin release by 40-60%. None of the test animals died at the maximum dose 500mg/kg and did not cause any significant change in general feature, water and food consumption, body weight and organ weight when we examined the acute oral toxicity of those compounds having significant hypoglycemic effect.

A previously undescribed intron and extensive 5' upstream sequence, but not Phox2a-mediated transactivation, are necessary for high level cell type-specific expression of the human norepinephrine transporter gene

The synaptic action of norepinephrine is terminated by NaCl-dependent uptake into presynaptic noradrenergic nerve endings, mediated by the norepinephrine transporter (NET). NET is expressed only in neuronal tissues that synthesize and secrete norepinephrine and in most cases is co-expressed with the norepinephrine-synthetic enzyme dopamine beta-hydroxylase (DBH). To understand the molecular mechanisms regulating human NET (hNET) gene expression, we isolated and characterized an hNET genomic clone encompassing approximately 9. 5 kilobase pairs of the 5' upstream promoter region. Here we demonstrate that the hNET gene contains an as-yet-unidentified intron of 476 base pairs within the 5'-untranslated region. Furthermore, both primer extension and 5'-rapid amplification of cDNA ends analyses identified multiple transcription start sites from mRNAs expressed only in NET-expressing cell lines. The start sites clustered in two subdomains, each preceded by a TATA-like sequence motif. As expected for mature mRNAs, transcripts from most of these sites each contained an additional G residue at the 5' position. Together, the data strongly support the authenticity of these sites as the transcriptional start sites of hNET. We assembled hNET-chloramphenicol acetyltransferase reporter constructs containing different lengths of hNET 5' sequence in the presence or the absence of the first intron. Transient transfection assays indicated that the combination of the 5' upstream sequence and the first intron supported the highest level of noradrenergic cell-specific transcription. Forced expression of the paired-like homeodomain transcription factor Phox2a did not affect hNET promoter activity in NET-negative cell lines, in marked contrast to its effect on a DBH-chloramphenicol acetyltransferase reporter construct. Together with our previous studies suggesting a critical role of Phox2a for noradrenergic-specific expression of the DBH gene, these data support a model in which distinct, or partially distinct, molecular mechanisms regulate cell-specific expression of the NET and DBH genes.

Near infrared spectroscopic monitoring of secondary cerebral energy failure after transient global hypoxia-ischemia in the newborn piglet

The present study was done to establish whether the secondary cerebral energy failure could be reproduced in the newborn piglet subjected to transient global hypoxia-ischemia, and whether the evolution of secondary cerebral energy failure could be monitored by measuring the changes of Cyt aa3 using NIRS. Fifteen anesthetized, ventilated newborn piglets (< 3 day) were divided into 2 groups. Eight of hypoxia-ischemia (HI) group were induced transient HI by breathing 8% oxygen and complete occlusion of bilateral common carotid arteries for 30 min followed by release of occluders and reoxygenation and maintained for up to 48 h. Seven were given sham operation and maintained for 48 h also. Monitoring of cerebral Hb, HbO, HbT and Cyt aa3 were continued throughout the experiment using near infrared spectroscopy. Na+, K(+)-ATPase activity, lipid peroxidation products (conjugated dienes), tissue high energy phosphates (ATP and phosphocreatine) levels and brain glucose and lactate levels were determined biochemically in the cerebral cortex harvested at the termination of experiment. HbT as an index of a cerebral blood volume increased at 2 h after resuscitation significantly in HI group. During hypoxia-ischemia Cyt aa3 fell to -2.0 +/- 0.5 mu l-1 (p < 0.01), returned to baseline on resuscitation, but decreased again progressively from 33 h, and finally fell to -2.2 +/- 0.9 mumol l-1 (p < 0.01) at 48 h in spite of normal physiologic values. There were no changes in control animals. Cerebral level of ATP and PCr in HI group decreased significantly compared to control and ATP concentrations were correlated with the final levels of Cyt aa3. In HI group, cerebral Na+, K(+)-ATPase activity decreased, but the cerebral level of conjugated dienes, glucose, lactate was not different compared to controls. These findings suggest that secondary cerebral energy failure was successfully reproduced in the newborn piglets after transient hypoxia-ischemia and the continuous in vivo NIRS monitoring can be used as a useful tool for the monitoring of delayed cerebral injury.

Apolipoprotein E alters metabolism of AbetaPP in cells engaged in beta-amyloidosis

Canine smooth muscle cells (SMCs), cultured from amyloid-affected brain blood vessels accumulate Alzheimer amyloid-beta peptide (Abeta) intracellularly, either spontaneously or after treatment with apolipoprotein E (apoE). ApoE is codeposited with Abeta, which suggests that apoE participates in Abeta accumulation. We tested the hypothesis that apoE-induced accumulation of Abeta in SMCs is caused by an increased production of amyloid-beta precursor protein (AbetaPP) and/or its altered metabolism. We found that 24 hours of treatment with apoE3 or apoE4 induced intracellular accumulation of Abeta-immunoreactive deposits in SMCs but did not influence AbetaPP production and processing. The treatment with apoE3 or E4 for 3 days resulted in the following: increased Abeta-accumulation; reduced levels of secreted Abeta; increased production and cellular retention of mature AbetaPP770; and reduced culture growth, cell proliferation, and viability. ApoE4, but not apoE3, increased cellular levels of mRNA AbetaPP 770 (the main form produced in SMCs) about ninefold. ApoE3 stimulated production and cellular retention of endogenous apoE. We hypothesize that Abeta accumulation is triggered by apoE, which may bind and immobilize soluble Abeta produced in SMCs. The newly formed Abeta deposits may further accelerate Abeta accumulation by altering metabolism of AbetaPP.

Identification and characterization of a novel Ibe10 binding protein that contributes to Escherichia coli invasion of brain microvascular endothelial cells

The molecular basis of Escherichia coli traversal of the blood-brain barrier in the development of E. coli meningitis is not well understood. We have previously shown that a novel Ibe10 protein found in cerebrospinal fluid isolates of E. coli is necessary for invasion of the brain microvascular endothelial cells (BMEC) that constitute the blood-brain barrier both in vitro and in a newborn rat model of hematogenous meningitis. Here we identified a novel Ibe10 binding molecule/receptor (Ibe10R) on both bovine BMEC (HBMEC) and human BMEC (HBMEC) that is responsible for invasion by E. coli. Ibe10R, an approximately 55-kDa protein, was purified from BBMEC by Ibe10-Ni-Sepharose affinity chromatography. Bovine Ibe10R, as well as polyclonal antibodies to Ibe10R, blocked E. coli invasion of BBMEC very effectively. The N-terminal amino acid sequence of Ibe10R showed 75% homology to serum albumin. However, the amino acid sequence of an Ibe10R fragment generated by limited enzymatic digestion did not reveal homology to any other proteins, suggesting that Ibe10R represents a novel albumin-like protein. Immunocytochemical analysis of BBMEC using anti-Ibe10R antibody suggested that only a subset of cultured BBMEC express Ibe10R on their surface. Enrichment of Ibe10R-positive BBMEC by fluorescence-activated cell sorting with anti-Ibe10R antibody resulted in enhanced invasion by E. coli. The anti-Ibe10R antibody raised against bovine Ibe10R also blocked E. coli invasion of HBMEC very effectively. Interestingly, anti-Ibe10R antibody affinity chromatography of HBMEC membrane proteins revealed a smaller protein with an approximate molecular mass of 45 kDa. These results suggest that the Ibe10 of E. coli interacts with a novel BMEC surface protein, Ibe10R, for invasion of both BBMEC and HBMEC.

Quantification of sub-femtomole amounts of Alzheimer amyloid beta peptides

We evaluated methods for the quantitative Western blot analysis of A beta 1-40 and A beta 1-42. Both chromogenic and chemiluminescent detection methods gave similar sensitivities (0.15 fmol of A beta 1-40 and 0.3 fmol of A beta 1-42); however, the chromogenic method was more rapid, simpler, less expensive and gave fewer background problems; consequently, it yielded more reliable results. Adsorption to various types of laboratory plasticware can greatly interfere with the accurate measurement of A beta, but this can be prevented by the addition of SDS or bovine serum albumin. Among several methods for concentrating A beta from biological materials, immunoadsorption to Sepharose-bound antibodies was the most efficient. It yielded 50% recovery of 1 pM A beta 1-42 or A beta 1-40 and so was a suitable method to measure A beta levels in human plasma. Through combined immunoadsorption and Western blotting we could determine the amounts of A beta isoforms secreted from 1 x 10(6) cells after a culture period as short as 1 h. This eliminates the need to use radiolabelling or over-expression to study A beta precursor processing Bovine serum contains subnanomolar A beta levels, similar to those that reportedly stimulate cell proliferation. That cultured cells quickly secrete these levels of A beta suggests that the peptide might exert an autocrine effect.

Rabbits treated with chronic isepamicin are resistant to mivacurium and rocuronium

We compared the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium after chronic isepamicin therapy for 7 days in 56 anesthetized rabbits. Train-of-four stimuli were applied every 10 s to the common peroneal nerve, and the force of contraction of the tibialis anterior muscle was measured. Chronic isepamicin therapy is associated with a rightward shift of the mivacurium and rocuronium dose-response curves. The effective dose for 50% twitch depression of mivacurium and rocuronium increased significantly, from 16.9 +/- 4.8 and 56.5 +/- 5.3 microg/kg, respectively, with placebo to 30.6 +/- 5.3 and 75.6 +/- 4.7 microg/kg, respectively, during isepamicin therapy. The isepamicin rabbits receiving mivacurium 0.18 mg/kg or rocuronium 0.6 mg/kg had an accelerated recovery from neuromuscular blockade compared with those receiving placebo. The results of this study show that mivacurium and rocuronium have both a decreased effect and a shorter duration of action in rabbits when used during concurrent isepamicin therapy.

IMPLICATIONS

We studied the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium during chronic isepamicin therapy in rabbits. Mivacurium and rocuronium have both a decreased effect and a shorter duration of action during chronic aminoglycoside antibiotic therapy in rabbits.

Percutaneously implantable catheter-port system for chemotherapeutic infusion through the hepatic artery

OBJECTIVE

The goal of this study was to determine the feasibility and outcomes of percutaneously implantable catheter-port system placement in the hepatic artery for the purpose of intraarterial chemotherapeutic infusion.

CONCLUSION

Percutaneously implantable catheter-port system placement is safe and technically feasible for use in the hepatic artery. The implantation procedure is less invasive than surgical implantation of similar port systems.

Polymorphism analysis of the CYP1A1 locus in Koreans: presence of the solitary m2 allele

This study determined the complete genotype and the frequencies of all four mutations [T6235C (m1), A4889G (m2), T5639C (m3) and C4887A (m4)] of the CYP1A1 from 48 healthy Koreans and 17 Korean lung cancer patients. The mutations were analyzed by polymerase chain reaction (PCR)/restriction fragment length polymorphism (RFLP) and single stand conformation polymorphism (SSCP) simultaneously in order to improve accuracy as well as to screen for possible new alleles. Previously, the m2 mutation has always been linked to the m1 mutation. Also, the m1m2 double mutant allele (*2B) was thought to have a positive correlation with lung cancer susceptibility. Here we report the presence of the solitary m2 mutant allele without the m1 mutation (m1+m2) for the first time. This would be an evidence to support the theory of intragenic recombination in the CYP1A1 locus. The m1 mutation frequencies of healthy Koreans and lung cancer patients were 38.5% and 29.4%, respectively. The m2 mutation frequencies of healthy Koreans and lung cancer patients were 25.0% and 14.7%, respectively. Unlike the case for both Japanese and Caucasian lung cancer patients, neither m1 nor m2 mutations were overrepresented in Korean lung cancer patients. The m2 mutation frequency in Korean patients was significantly higher than those for Caucasians (2.7%) and the Japanese (19.8%). The African-American specific m3 mutation and m4 mutation found in Caucasians were not discovered in this study. The CYP1A1 allele with novel mutation was also not present.

N-acetylcysteine increases the biosynthesis of recombinant EPO in apoptotic Chinese hamster ovary cells

Sodium butyrate (NaBu) is known to enhance the rate of biosynthesis of recombinant proteins in Chinese hamster ovary cells (CHO). Here we demonstrate that supplementation with NaBu during rapid growth brings about abrupt death of the cells. The death of the cells is due to apoptosis, as assessed by intranucleosomal DNA fragmentation. The promotion of apoptotic death of the cells could be partially blocked by treatment with the well-known antioxidant, N-acetylcysteine (NAC). Strikingly, the NAC treatment enhanced the production of recombinant EPO two-fold compared with that of the culture without NAC supplementation. These results showed that NaBu treatment supplemented with NAC not only inhibits apoptosis, but also exerts a synergistic effect on the biosynthesis of recombinant EPO.

Clinical significance of intrahepatic biliary stricture in efficacy of hepatic resection for intrahepatic stones

In the Far East, hepatic resection is the definitive treatment for complicated intrahepatic stones (IHS). However, many investigators have reported that the associated intrahepatic biliary stricture is the main cause of treatment failure. A retrospective comparative study was undertaken to clarify the long-term efficacy of hepatic resection for treatment of IHS and to investigate the clinical significance of intrahepatic biliary stricture in treatment failure after hepatic resection performed in 44 patients with symptomatic IHS. The patients were divided into two study groups: group A, with intrahepatic biliary stricture (n = 28) and group B, without stricture (n = 16). Residual or recurrent stones, recurrence of intrahepatic biliary stricture, late cholangitis, and final outcomes were analyzed and compared statistically between the two groups. The patients were followed up for a median duration of 65 months after hepatectomy. The overall incidence of residual or recurrent stones was 36% and 11%, respectively, in groups A and B. The initial treatment failure rate was 50% in group A and 31% in group B. Intrahepatic biliary stricture recurred in 46% of patients in group A, while none of the group B patients had biliary stricture recurrence (P = 0.001). More than two-thirds of the restrictures in group A were identified at the primary site. The incidence of late cholangitis was higher in group A (54%) than in group B (6%) (P = 0. 002). Three-quarters of the patients with cholangitis in group A had severe cholangitis, that was recurrent, and related to stones and strictures (n = 11). They and 2 asymptomatic patients in group B required secondary procedures done at a median of 12 months after hepatectomy. Final outcomes after hepatectomy with or without secondary management were good in 80%, fair in 16%, and poor in 4% of our 44 patients. Most recurrent cholangitis after hepatectomy in patients with IHS was related to recurrent intrahepatic ductal strictures. Therefore, to be effective, hepatic resection should include the strictured duct. However, with hepatectomy alone it is difficult to clear the IHS or relieve the ductal strictures completely, particularly in patients with bilateral IHS, so perioperative team approaches that include both radiologic and cholangioscopic interventions should be combined for the effective management of IHS.

Clinical characteristics and outcome of children with pneumonia attributable to penicillin-susceptible and penicillin-nonsusceptible Streptococcus pneumoniae

OBJECTIVE

To compare the clinical characteristics, treatment, and outcome of pediatric patients with pneumonia attributable to isolates of Streptococcus pneumoniae that were either susceptible or nonsusceptible to penicillin.

DESIGN

Multicenter, retrospective study.

SETTING

Eight children's hospitals in the United States.

PARTICIPANTS

Two hundred fifty-four children with pneumococcal pneumonia identified from patients enrolled in the United States Pediatric Multicenter Pneumococcal Surveillance Study during the 3-year period from September 1, 1993 to August 31, 1996.

OUTCOME MEASURES

Demographic and clinical variables including necessity for and duration of hospitalization, frequency of chest tube placement, antimicrobial therapy, susceptibility of isolates, and clinical outcome.

RESULTS

There were 257 episodes of pneumococcal pneumonia that occurred in 254 patients. Of the 257 isolates, 22 (9%) were intermediate and 14 (6%) were resistant to penicillin; 7 (3%) were intermediate to ceftriaxone and 5 (2%) were resistant to ceftriaxone. There were no differences noted in the clinical presentation of the patients with susceptible versus nonsusceptible isolates. Twenty-nine percent of the patients had a pleural effusion. The 189 (74%) hospitalized patients were more likely to have an underlying illness, multiple lung lobe involvement, and the presence of a pleural effusion than nonhospitalized patients. Fifty-two of 72 hospitalized patients with pleural effusions had a chest tube placed, and 27 subsequently underwent a decortication drainage procedure. Eighty percent of the patients treated as outpatients and 48% of the inpatients received a parenteral second or third generation cephalosporin followed by a course of an oral antimicrobial agent. Two hundred forty-eight of the patients (97.6%) had a good response to therapy. Six patients died; however, only 1 of the deaths was related to the pneumococcal infection.

CONCLUSION

The clinical presentation and outcome of therapy did not differ significantly between patients with penicillin-susceptible versus those with nonsusceptible isolates of S pneumoniae. Hospitalized patients were more likely to have underlying illnesses, multiple lobe involvement, and the presence of pleural effusions than patients who did not require hospitalization. In otherwise normal patients with pneumonia attributable to penicillin-resistant pneumococcal isolates, therapy with standard beta-lactam agents is effective.

Cloning and expression of cDNA for a human Sia alpha 2,3Gal beta 1, 4GlcNA:alpha 2,8-sialyltransferase (hST8Sia III)

The cDNA encoding human Sia-alpha2,3-Gal-beta1,4-GlcNAc-R:alpha2, 8-sialyltransferase, hST8Sia III, was isolated by screening of a human brain cDNA library with polymerase chain reaction-amplified DNA probe generated from the sequence of mouse ST8Sia III (mST8Sia III) and by 5' rapid amplification of cDNA ends of mRNA isolated from human brain tissues. Comparative analysis of the predicted protein-coding region between our cloned hST8Sia III and mST8Sia III showed 92 and 96% identities in the nucleotide and the amino acid sequence, respectively. The soluble hST8Sia III protein expressed in COS-7 showed an extremely high catalytic activity of transferring sialic acid through alpha2,8-linkage to intact fetuin glycoprotein, whereas the transferring activity was completely undetectable toward either alpha2,6-sialylated glycoprotein or desialylated glycoprotein acceptors. Northern analysis of hST8Sia III showed that the transcript corresponding to 11 kb was expressed in both human fetal and adult brain, while the expression of the 5.5-kb transcript was restricted to fetal liver, indicating that the expression of hST8Sia III is developmentally and tissue-specifically regulated.