Antagonism of p53-dependent apoptosis by mitogen signals

p53-mediated apoptosis is antagonized by growth factor stimulation. Here, we show that p53-dependent cell death induced by DNA damage was effectively prevented by mitogen activation. The levels of Bcl-2, Bcl-xL, and Bax were not altered by cisplatin treatment and mitogen rescue. Instead, the protection against p53-regulated apoptosis was mediated by at least three distinct signaling pathways. Either phosphatidylinositol (PI) 3-kinase or mitogen-activated protein kinase kinase (MEK) antagonized p53-induced apoptosis, and an additive preventive effect was observed when both kinases were activated. However, the combination of PI 3-kinase and MEK was not sufficient to completely prevent apoptosis induced by DNA damage. Mitogen activation further suppressed cisplatin-induced p53 expression, and the inhibition was mainly dependent on the Ca2+ pathway. Our results demonstrate that effective antagonism of p53-dependent apoptosis by mitogenic activation requires the presence of multiple signal pathways, including PI 3-kinase, MEK, and Ca2+.

Requirement of I-E molecule for thymocyte apoptosis induced by staphylococcal enterotoxin B in vivo

In vivo administration of bacterial superantigen staphylococcal enterotoxin B (SEB) to BALB/c mice led to thymus atrophy resulting from thymocyte apoptosis. In this study, we demonstrated that SEB induced a substantial reduction in thymocyte numbers in BALB/c, B10. D2 (H-2(d) haplotype), B10.BR, C3H/HeJ, C3H/HeN (H-2(k)), and (BALB/c x B6)F1 (H-2(dxb)), but caused little or no effect in I-E- strains such as B6, B10, A.BY (H-2(b)), and A.SW (H-2(s)) mice. Elimination of CD4(+)CD8(+) cells predominantly accounted for the thymocyte loss, although the numbers of other subpopulations may also be reduced. Thymocyte apoptosis was shown by an increase in the level of DNA fragmentation in BALB/c but not in B6 mice after SEB administration. Treatment with anti-I-Ed monoclonal antibody to BALB/c mice blocked SEB-induced thymocyte apoptosis when anti-I-Ad exerted less effect. In contrast to SEB, staphylococcal enterotoxin A led to comparable levels of thymus atrophy in BALB/c and B6 mice. Studies on the surface marker expression indicated that CD25 expression was upregulated on BALB/c mouse thymocytes but with only a moderate increase in B6 mice. The CD4(+)CD8(+) cells were the major (>90%) population that expressed elevated levels of CD25 in BALB/c mice. An increase in the expression of TCRalphabeta, CD3, and CD69 surface markers was also observed on thymocytes from BALB/c mice, but not from I-E- strains. The differential response of I-E+ and I-E- mice to SEB may be exploited as a model for the study of apoptosis in the thymus.

Controlling Legionella in hospital water systems: experience with the superheat-and-flush method and copper-silver ionization

OBJECTIVE

To evaluate the effect of copper-silver ionization on Legionella colonization and nosocomial legionnaires' disease and to compare the efficacy of metal ions versus the superheat-and-flush method of disinfection.

DESIGN

Prospective determination over a 36-month period of copper and silver ion concentrations in the recirculating hot-water system, Legionella colonization of the hospital water distribution system, and cases of nosocomial legionnaires' disease. Retrospective comparison of results with the previous 13 years, during which the superheat-and-flush method was used.

SETTING

The Pittsburgh Veterans' Affairs Health Care System (University Drive Division) acute-care hospital.

INTERVENTION

Three copper-silver ionization systems were installed on the hot-water distribution system in November 1994.

RESULTS

The average number of cases of legionnaires' disease per year and the percentage of distal sites positive for Legionella pneumophila for the superheat-and-flush method versus the copper-silver ionization method was six cases with 15% positivity versus two cases with 4% positivity, respectively. The reduction in Legionella colonization after copper-silver ionization was significant (P<.05) compared to the superheat and flush. Mean copper and silver ion concentrations (mg/L) were 0.29 and 0.054 from hot-water tanks, and 0.17 and 0.04 from distal outlets, respectively.

CONCLUSIONS

We conclude that a properly maintained and monitored copper-silver ionization system was more effective than the superheat-and-flush method for reducing the recovery of Legionella from the hospital water distribution system.

Inhibition of hTAFII32-binding implicated in the transcriptional repression by central regions of mutant p53 proteins

We previously identified a movable and regulable inactivation function within the central region (CRts247) of a temperature-sensitive p53 (p53(ts)) mutant, p53(N247I). Here we showed that central regions from several p53(ts) mutants behaved similarly, i.e. they repressed a neighboring activation domain only when existing in the mutant status. Using chimeric protein GAL4VP16-CRts247 as an example, we demonstrated that de novo protein synthesis was not required for the reactivation of the chimeric protein, indicating that a post-translational mechanism was involved in the control of CRts247 activity. The CRts247-conferred thermo-regulability did not work via a mechanism demanding either an alteration of the subcellular compartmentalization of or the inactivation of DNA-binding activity of the GAL4 chimera. Further, CRts247 did not function in trans, eliminating the possibility that the observed repression was because of the competition for a putative factor(s) by the mutant p53 domain. Rather, CRts247 bestowed temperature-dependent interaction with hTAFII32 to the VP16 activation domain. In a parallel experiment, CRts247 also caused a large reduction in the affinity of hTAFII32 to the p53 activation domain at the nonpermissive temperature. These results strongly suggested that inhibition of hTAFII32 binding could be one of the mechanisms responsible for the transcriptional repression by mutant p53 central regions.

Comparison of the characteristics of double-pass erbium-doped superfluorescent fiber sources obtained from different flattening techniques

We investigate and compare the characteristics of erbium-doped superfluorescent fiber sources (SFS's) obtained from the use of different flattening techniques in double-pass forward (DPF) and double-pass backward (DPB) configurations. The intrinsic flattening technique consists of optimizing the length of the erbium-doped fiber. The extrinsic flattening methods include the addition of a samarium-doped fiber (SDF) and a fiber-Bragg-grating (FBG) notched filter at the output end separately to shape the SFS spectrum. Although intrinsically flattened DPF and DPB SFS's have a large output power of >34 mW, they are accompanied by an approximately 3-dB ripple. The FBG-flattened DPF and DPB SFS's can achieve a wide linewidth of 35 nm with a small ripple of approximately 1.7 dB and better pump-power-dependent mean-wavelength stability; SDF-flattened DPF and DPB SFS's are inferior because of the SDF's lossy spectrum.

Streptococcal pyrogenic exotoxin B induces apoptosis and reduces phagocytic activity in U937 cells

Treatment of U937 human monocyte-like cells with Streptococcus pyogenes led to an induction of apoptosis in these cells. A comparison between the wild-type strain and its isogenic protease-negative mutant indicated that the production of streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, caused a greater extent of apoptosis in U937 cells. Further study using purified SPE B showed that this protease alone could induce U937 cells to undergo apoptosis, which was characterized by morphologic changes, DNA fragmentation laddering on the gel, and an increase in the percentages of hypodiploid cells. The protease activity of SPE B was required for apoptosis to proceed, since treatment with cysteine protease inhibitor E64 or heat inactivation abrogated this death-inducing effect. The SPE B-induced apoptosis pathway was interleukin-1beta converting enzyme (ICE) family protease dependent. Further experiments showed that the phagocytic activity of U937 cells was reduced by SPE B. Treatment with E64 and heat inactivation both abrogated this phagocytosis-inhibitory effect. Taken together, the present data show that SPE B not only possesses the ability to induce apoptosis in monocytic cells but also helps bacteria to resist phagocytosis by host cells.

Preclinical pharmacokinetics, interspecies scaling, and tissue distribution of a humanized monoclonal antibody against vascular endothelial growth factor

Vascular endothelial growth factor (VEGF) plays a crucial role in angiogenesis and in pathological processes such as tumor growth, rheumatoid arthritis, and ocular neovascularization. A recombinant humanized monoclonal antibody (rhuMAb), rhuMAb VEGF, has been developed to inhibit the effects of VEGF in the treatment of solid tumors. Intravenous and s.c. pharmacokinetic studies were conducted in mice, rats, and cynomolgus monkeys. In addition, the tissue distribution of i.v. 125I-rhuMAb VEGF was investigated in rabbits. At a dose of approximately 10 mg/kg, the clearance of rhuMAb VEGF from the serum was 15.7 ml/day/kg in mice, 4.83 ml/day/kg in rats, and 5.59 ml/day/kg in cynomolgus monkeys, and the terminal half-life ranged from 6 to 12 days in all species. After s.c. administration, rhuMAb VEGF had a bioavailability of 69% in rats and 100% in mice and cynomolgus monkeys. Pharmacokinetic data in mice, rats, and cynomolgus monkeys were used to predict the pharmacokinetics of rhuMAb VEGF using allometric scaling in humans. The predicted serum clearance of rhuMAb VEGF in humans was 2.4 ml/day/kg and the terminal half-life was 12 days. Two hours after i.v. bolus administration of 125I-rhuMAb VEGF in rabbits, trichloroacetic acid-precipitable radioactivity was noted primarily in the plasma, with lesser amounts in highly perfused tissues such as kidneys, testes, spleen, heart, and lungs. At 48 h after dosing, trichloroacetic acid-precipitable radioactivity was noted in plasma with minimal distribution to testes, bladder, heart, lungs, and kidneys. Tissue distribution and pharmacokinetic data indicate that rhuMAb VEGF is cleared slowly and distributes to specific sites in the body.

ED staff members' personal use of complementary therapies and their recommendations to ED patients: a southeastern US regional survey

BACKGROUND

Use of complementary and alternative therapies has increased in the United States during the past 5 years. Little is known about the use of these therapies in emergency departments.

METHODS

The Center for the Study of Complementary and Alternative Therapies, University of Virginia, surveyed staff in 10 emergency departments in the southeast region of the United States with the purpose of exploring ED practitioners' personal use of complementary therapies and recommendations of these therapies to patients.

RESULTS

ED staff reported back rub or massage, music, and prayer or spiritual practices as the 3 most frequently used complementary therapies for personal well-being. Back rub or massage and spiritual practices including prayer and group support were most frequently recommended to patients. Clinicians expressed interest in acquiring additional knowledge of complementary therapies and support for integration of these therapies in emergency departments.

CONCLUSIONS

Use of complementary therapies for personal well-being and for patient care by ED staff in the southeast region of the United States is limited. Most ED staff are not familiar with these therapies, but a majority of staff (70%) want to learn more about them. Findings suggest that ED nurses would like additional training in, and better referral patterns to, complementary therapies.

Molecular cloning of bovine telomerase RNA

Telomerase is a ribonucleoprotein reverse transcriptase essential for the maintenance of telomere length. However, the available information concerning the biochemical and structural aspects of mammalian telomerases is scarce, primarily due to the low abundance of these enzymes and the difficulty and expense involved in its purification. To overcome these problems, we started to purify and characterize telomerase from bovine testis. Bovine telomerase was purified over columns of hydroxyapatite, DEAE-Sepharose, heparin-agarose, phenyl-agarose and spermine-agarose. In a sedimentation study performed using a 15-40% glycerol gradient, partially purified bovine telomerase exhibited an apparent molecular weight of more than 1000 kDa. One 435-bp RNA, bTR, was cloned from the most purified telomerase fraction and shown to be co-purified with telomerase activity in a glycerol gradient. bTR shares 83% similarity to the human telomerase RNA and 65% to the mouse telomerase RNA. A putative template region encompassing 10 nucleotides (5'-CUAACCCUAA-3') complementary to the mammalian telomere sequence (TTAGGG)n is located between nucleotides 38-47 of bTR. Besides, the bTR 5'-flanking region shares only three regulatory elements with that of hTR: a TATA-like sequence, a CCAAT box and an E1A-F box. Furthermore, the addition of in-vitro transcribed bTR reconstituted telomerase activity after removal of the endogenous bTR by micrococcal nuclease digestion. Northern blot analysis identified a single RNA of about 430-440 nucleotides expressed in the bovine testis and an immortalized bovine cell line. Taken together, these data strongly suggest that bTR is the RNA component of bovine telomerase.

Peripheral neural modulation of endotoxin-induced hyperventilation

OBJECTIVE

To delineate the role of the peripheral neural reflexes involved in modulating hyperventilation during endotoxemia.

DESIGN

A prospective, randomized, controlled, multigroup study.

SETTING

Research animal laboratory.

SUBJECTS

Adult Sprague-Dawley rats (n=43; 354+/-24 g) of either gender.

INTERVENTIONS

Eight rats received a sham operation on their vagus, carotid sinus, and aortic nerves before the administration of a saline vehicle to serve as the time control. In the endotoxin group, 11 rats received a sham operation before endotoxin challenge. The remaining 24 rats received bilateral vagotomy (n=8), perivagal capsaicin treatment (n=8), or denervation of peripheral chemoreceptors (n=8) before endotoxin challenge. After the breathing pattern returned to a steady state, endotoxin (L-4130, serotype 0111, B4 lipopolysaccharide; 50 mg/kg) was injected into the vein. The rat's respiration was then monitored continuously for 5 hrs or until the animal died.

MEASUREMENTS AND MAIN RESULTS

The respiratory rate and tidal volume did not change over the 5-hr observation period in the time control group. In the endotoxin group, the respiratory rate increased significantly from baseline (135.4%) 2 hrs after endotoxin challenge and increased persistently until the rats died. The tidal volume increased gradually to < or =132.8% of baseline 4 hrs after endotoxin challenge. Bilateral cervical vagotomy and perineural capsaicin treatment of the vagus nerves eliminated the tachypnea response to endotoxin injection. Denervation of the peripheral chemoreceptor accentuated the hyperventilation response to endotoxin, and resulted in the shortest survival time.

CONCLUSIONS

Both lung vagal C-fiber afferents and peripheral chemoreceptors are involved in modulating the hyperventilation response after endotoxin challenge in rat models. Stimulation of vagal C-fiber afferents increased the respiratory rate. Conversely, the role of peripheral chemoreceptors was to restrain the hyperventilatory response and these receptors may play a protective role during endotoxemia.

Pharmacokinetics and pharmacodynamics of sibrafiban (Ro 48-3657), an orally active IIb/IIIa antagonist, administered alone or in combination with heparin, aspirin, and recombinant tissue-type plasminogen activator in beagles

This study characterized the pharmacokinetics (PK) and pharmacodynamics (PD) of sibrafiban (Ro 48-3657) in the presence of aspirin, heparin, and recombinant tissue-type plasminogen activator (rt-PA) in beagles. Sibrafiban is a double prodrug that undergoes bioconversion to the inactive prodrug Ro 48-3656 and to the active IIb/IIIa antagonist, Ro 44-3888, after oral administration. After oral sibrafiban, peak Ro 48-3656 plasma concentrations were observed earlier than Ro 44-3888 and were five- to sixfold higher than Ro 44-3888 peak concentrations. Administration of sibrafiban with heparin and aspirin or heparin and rt-PA did not alter sibrafiban PK. Ro 48-3656 and Ro 44-3888 PK and inhibition of platelet-aggregation profiles in groups treated with sibrafiban and heparin/aspirin or sibrafiban and heparin/rt-PA were similar to those of the group receiving sibrafiban alone. Sibrafiban resulted in >80% inhibition of adenosine diphosphate (ADP)-mediated platelet aggregation and an approximate sixfold increase in bleeding time (BT) compared with baseline measurements. The BT increase was greater in the sibrafiban, heparin, and rt-PA-treated group, during rt-PA administration, compared with the group treated with sibrafiban alone. The recovery of platelet aggregation may be slower after administration of sibrafiban with heparin and rt-PA. Sibrafiban had no effect on rt-PA PK or heparin PD.

Role of streptococcal pyrogenic exotoxin B in the mouse model of group A streptococcal infection

Streptococcal pyrogenic exotoxin B (SPE B) is a cysteine protease produced by Streptococcus pyogenes. In this study, the differences in virulence between protease-positive clinical isolates and their protease-negative mutants were examined in a mouse model. Isogenic protease-negative mutants were constructed by homologous recombination, using integrational plasmids to disrupt the speB gene. These mutants caused less mortality and tissue damage than protease-positive strains when inoculated into BALB/c mice via air pouch, suggesting that SPE B cysteine protease plays an important role in the pathogenesis of S. pyogenes infection. Reconstitution of SPE B in the air pouches increased the mortality of mice receiving the speB mutant strain. Infiltrated cell numbers in the exudates from the air pouches of mice infected with SPE B-producing S. pyogenes were higher than those from mice infected with protease-negative mutants at 12 h. However, despite pretreatment with vinblastine to deplete neutrophils, injection of protease-positive bacteria still resulted in severe tissue injury, indicating that neutrophil infiltration may not be the major factor involved in SPE B-enhanced tissue damage. The role of SPE B was further confirmed by demonstrating that SPE B immunization of mice conferred protection from challenge with a lethal dose of protease-positive bacteria.

Inhibition of immune cell proliferation with haloperidol and relationship of tyrosine hydroxylase expression to immune cell growth

Previous studies indicated that exogenous dopamine and its agonists directly regulated mitogen-induced immune cell proliferation. In this study, we further investigated role of endogenous dopamine in immune cell growth. Haloperidol, a general antagonist for dopamine receptors, could reduce the cell growth rate of T cell hybridoma (10I) and rat nervous pheochromocytoma cells (PC12). Tyrosine hydroxylase (TH) catalyzes the initial rate-limiting step of catecholamine biosynthesis in the nervous system. Flow cytometric analysis indicated the expression of TH in various immune cells. The presence of TH in PC12 cells was used as a control. Temporal studies indicated that the expression of TH increased during 10I cell growth. Both alpha-methyl-p-tyrosine and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine reduced TH expression and cell growth in a dose-dependent manner. These results suggest that immune T cells express TH which is correlated to cell growth, and that dopamine released from these cells may bind to the receptors to act in an autocrine or paracrine way.

Disinfection of water distribution systems for Legionella

Hospital-acquired legionnaires' disease arises from the presence of Legionella in hospital water systems. Legionella not only persists in hot water tanks but is also found in the biofilm throughout the entire water distribution system. Conditions within water systems that promote Legionella colonization include water temperature, configuration and age of the hot water tank, physicochemical constituents of the water, plumbing materials, and commensal microflora. Hospital-acquired legionnaires' disease has been prevented by instituting control measures directed at the water distribution system. These include superheat-and-flush, copper/silver ionization, ultraviolet light, instantaneous heating systems, and hyperchlorination. Each of the above disinfection methods has been proven to be effective in the short-term, but long-term efficacy has been difficult due to limitations associated with each method. The complexities of Legionella disinfection, including advantages and disadvantages of each method, are reviewed. A successful Legionella prevention program requires cooperation and communication among hospital administrative personnel, engineers, and infection control staff. Routine environmental surveillance cultures for Legionella are the critical component for successful long-term disinfection. Culture results document the efficacy of the disinfection method and alert the hospital staff to consider Legionella in hospitalized patients with pneumonia.

The telomeres of Streptomyces chromosomes contain conserved palindromic sequences with potential to form complex secondary structures

The chromosomes of the gram-positive soil bacteria Streptomyces are linear DNA molecules, usually of about 8Mb, containing a centrally located origin of replication and covalently bound terminal proteins (which are presumably involved in the completion of replication of the telomeres). The ends of the chromosomes contain inverted repeats of variable lengths. The terminal segments of five Streptomyces chromosomes and plasmids were cloned and sequenced. The sequences showed a high degree of conservation in the first 166-168bp. Beyond the terminal homology, the sequences diverged and did not generally cross-hybridize. The homologous regions contained seven palindromes with a few nucleotide differences. Many of these differences occur in complementary pairs, such that the palindromicity is preserved. Energy-optimized modelling predicted that the 3' strand of the terminal palindromes can form extensive hairpin structures that are similar to the 3' ends of autonomous parvovirus genomes. Most of the putative hairpins have a GCGCAGC sequence at the loop, with the potential to form a stable single C-residue loop closed by a sheared G:A pairing. The similarity between the terminal structures of the Streptomyces replicons and the autonomous parvoviral genomes suggests that they may share some structural and/or replication features.

In vitro gene transfer in mammalian cells via a new cationic liposome formulation

A new cationic liposome formulation of sphingosine (SP) and dioleoylphosphatidylethanolamine (DOPE) was developed as an efficient transfection reagent. This SP/DOPE liposome showed efficient transfection in a wide variety of mammalian cancer cells. No significant cytotoxicity of the SP/DOPE liposome to cells was observed. The tranfection activity was greater than that of a well-reported liposome which was made from a cholesterol derivative 3beta-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and the neutral lipid DOPE. In addition, the SP/DOPE liposome was found to be less toxic to cells than the DC-Chol/DOPE liposome. Stable transfections mediated by SP/ DOPE liposome were also demonstrated. These results suggest that the SP/DOPE liposome may provide a good gene delivery system to be used in the human cancer gene therapy.

Induction of thymocyte apoptosis in mice by Yersinia enterocolitica products

In-vivo administration of the culture supernates from Yersinia enterocolitica resulted in thymus atrophy in C3H/HeJ mice, known to be lipopolysaccharide (LPS)-nonresponders. The thymocytes underwent apoptosis as characterised by fragmented DNA ladders on agarose gel electrophoresis, a cell death detection ELISA and a morphological study by the TUNEL reaction. As a control, LPS treatment did not induce thymocyte apoptosis in C3H/HeJ mice. Flow cytometric analysis indicated that thymus atrophy was due predominantly to the deletion of CD4+ CD8+ T cells. When cells were undergoing apoptosis, an elevation in the percentage of T-cell receptor (TCR)-alphabeta(high) cells was observed at 24 h, which was correlated with the increase in the percentages of cells expressing high levels of the Vbeta6 and Vbeta8 TCR. Gel electrophoretic analysis demonstrated the presence of protein bands with mol.wts ranging from 17 to 65 kDa in Y. enterocolitica culture supernates.

Effect of group A streptococcal cysteine protease on invasion of epithelial cells

Cysteine protease of group A streptococci (GAS) is considered an important virulence factor. However, its role in invasiveness of GAS has not been investigated. We demonstrated in this study that two strains of protease-producing GAS had the ability to invade A-549 human respiratory epithelial cells. Isogenic protease mutants were constructed by using integrational plasmids to disrupt the speB gene and confirmed by Southern hybridization and Western immunoblot analyses. No extracellular protease activity was produced by the mutants. The mutants had growth rates similar to those of the wild-type strains and produced normal levels of other extracellular proteins. When invading A-549 cells, the mutants had a two- to threefold decrease in activity compared to that of the wild-type strains. The invasion activity increased when the A-549 cells were incubated with purified cysteine protease and the mutant. However, blockage of the cysteine protease with a specific cysteine protease inhibitor, E-64, decreased the invasion activity of GAS. Intracellular growth of GAS was not found in A-549 cells. The presence or absence of protease activity did not affect the adhesive ability of GAS. These results suggested that streptococcal cysteine protease can enhance the invasion ability of GAS in human respiratory epithelial cells.

The N-terminal 178-amino-acid domain only of the SV40 large T antigen acts as a transforming suppressor of the HER-2/neu oncogene

The deregulation of the HER-2/neu protooncogene was demonstrated in a wide variety of human cancers and shown to be correlated with the progress of malignancy and metastasis in animal models. Repression of HER-2/neu overexpression suppressed the malignant phenotypes of HER-2/neu-overexpressing cancer cells. This suggested that HER-2/neu may be a good target for developing anti-cancer drugs. We found a deletion mutant of simian virus 40 (SV40) large T antigen (LT) suppresses the HER-2/neu oncogene expression at the transcriptional level. PCR clones of this mutant SV40LT, named LT425, which contains the N-terminal region of amino acid residues 1-178 of SV40LT, were subcloned and stably transfected into the HER-2/neu-overexpressing human ovarian cancer SKOV3.ip1 cells. These LT425 clones were found to be able to down-regulate the endogenous production of p185(HER-2/neu). In addition, the LT425-expressing stable transfectants showed reduced growth rate, low soft agarose colony forming ability, and low tumorigenic potential as compared with the parental line. These data suggested that the N-terminal 178 amino acids domain only of SV40LT may act as a transforming repressor of HER-2/neu oncogene.

Determination of Ro 48-3656 in rat plasma by reversed-phase high-performance liquid chromatography. Comparison of 1.5-microm nonporous silica to 3.5-microm porous silica analytical columns

We describe a method for measuring Ro 48-3656 in EDTA rat plasma by neutral pH, reversed-phase high-performance liquid chromatography using a 1.5-microm nonporous silica, C18 analytical column and UV absorbance detection to support pharmacokinetic studies. We also describe a comparison of the 1.5-microm nonporous silica C18 column versus 3.5-microm porous silica C18 columns. The final method using the 1.5-microm nonporous silica column demonstrated good precision (of both quantification and retention time), accuracy and recovery, linearity of dilution and limit of quantification (40 ng/ml Ro 48-3656 using a 20 microl injection). Samples of neat EDTA rat plasma were prepared by ultrafiltration followed by direct injection onto the HPLC column.

Effect of dopamine on immune cell proliferation in mice

Dopamine is known as a precursor of catecholamine and one of the neurotransmitters in brain and peripheral tissues. Recent studies suggest an important role of dopamine in immune responses. In the present study, intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which lowered endogenous dopamine suppressed splenocyte proliferation in response to mitogens such as lipopolysaccharide (LPS) and concanavalin A (Con A). Moreover, intravenous injection of the specific agonists of dopamine DA-1 receptor (SKF38393) or DA-2 receptor (LY171555) into mice enhanced the splenocyte proliferation stimulated by LPS or Con A. In the in vitro cultures, dopamine, SKF38393 and LY171555 directly promoted cell proliferation to LPS or Con A. These results indicate that dopamine has an ability to regulate B- and T-cell proliferation both in vivo and in vitro.

Identification of the DRB1*1313 allele in a sibling pair

Sequence-specific oligonucleotide probe hybridization (PCR/SSOP), which is now routinely used in HLA laboratories to type for alleles of the class II loci, can also detect the presence of previously unknown alleles. In the course of clinical typing for DRB1, we identified two samples with probe hybridization patterns appropriate for DRB1*1313, a previously submitted sequence that had been withdrawn. Direct sequencing showed that the two individuals carried an allele with an exon 2 sequence identical to that previously submitted for DRB1*1313.

Negative regulation of a heterologous promoter by human cytomegalovirus immediate-early protein IE2

The HCMV IE2 protein promiscuously activates transcription of many viral and cellular genes. IE2 also negatively autoregulates its own expression by binding to a strategically positioned IE2 binding site, called CRS, located immediately downstream of the TATA box of the HCMV major IE promoter. Here we show that IE2 is able to repress transcription driven by a heterologous promoter, RSV LTR. Repression of RSV LTR by IE2 is completely dependent of DNA sequences downstream of the TATA box of RSV LTR. A DNA sequence, 5'-CGATACAATAAACG-3', evidently matching the proposed CRS consensus sequence, is located between nucleotides -13 and +1 (relative to the transcription start site) of RSV LTR. Three lines of evidence support the notion that this RSV CRS element is involved in the IE2-mediated repression of RSV LTR. First, introduction of mutation to the RSV CRS element renders to the mutant RSV LTR resistance to IE2-mediated repression. Second, a mutant IE2 defective in DNA binding cannot downregulate transcription from RSV LTR. Third, IE2 specifically binds to the wild-type, but not the mutant, RSV CRS element in vitro. These data, in conjunction with previous works, demonstrate that IE2 can passively repress transcription of homologous and heterologous promoters that contain a CRS element.

Instability of artificially circularized chromosomes of Streptomyces lividans

The chromosomes of Streptomyces species are linear molecules, containing long terminal inverted repeats and covalently bound terminal proteins. These chromosomes undergo spontaneous deletions of the terminal sequences at high frequencies and become circularized in several cases examined. Artificial circularization of the Streptomyces lividans chromosome was also achieved by targeted recombination in vivo, in which the terminal inverted repeats of the chromosome were connected by a kanamycin resistance gene (aphII). Under kanamycin selection, the circularized chromosomes harboured tandem amplifications of a 20.2 kb sequence that included the aphII gene flanked by direct repeats and deletions nearby. On release from kanamycin selection, the aphII amplifications and the neighbouring sequences were deleted from the chromosomes, rendering all the cultures kanamycin sensitive. The chloramphenicol resistance gene, which was prone to deletion in wild-type S. lividans, became much more stable in the kanamycin-sensitive derivatives. These results indicate that the telomeres and/or certain terminal sequences may be involved in the structural instability of Streptomyces chromosomes.

Reflex apneic response evoked by laryngeal exposure to wood smoke in rats: neural and chemical mechanisms

We investigated the neural and chemical mechanisms contributing to the immediate ventilatory responses to laryngeal exposure to wood smoke in anesthetized Sprague-Dawley rats. Five milliliters of wood smoke were delivered into a functionally isolated larynx at a constant flow rate of 1.4 ml/s while the animals breathed spontaneously. Within 1 s after exposure, laryngeal wood smoke consistently triggered an apnea in each of the 42 rats tested. The apneic duration reached 1,636.4 +/- 105.4 (SE) % (n = 42) of the baseline expiratory duration. This apneic response was not affected by denervation of recurrent laryngeal nerves (n = 6) or by removal of smoke particulates (n = 14), but it was totally eliminated by topical application of an anesthetic (n = 8; lidocaine hydrochloride, 8%) to the laryngeal mucosa or by sectioning of the superior laryngeal nerves (n = 42). Furthermore, laryngeal application of a hydroxyl radical scavenger (dimethylthiourea; 500 mg/ml; n = 8) greatly diminished or abolished the smoke-induced apneic response, but it did not affect the apneic response evoked by laryngeal exposure to air saturated with 6% ammonia. These results suggest that the immediate apneic response to laryngeal wood smoke is a reflex resulting from the stimulation of the superior laryngeal afferents by the gas phase of wood smoke and that the stimulation is mediated through a hydroxyl radical mechanism.

Enhanced deoxyribonucleic acid damage and repair but unchanged apoptosis in uterine leiomyomas treated with gonadotropin-releasing hormone agonist

OBJECTIVE

Our purpose was to investigate the histopathologic changes in uterine leiomyomas in cell proliferation, proliferating cell nuclear antigen expression, angiogenesis, and apoptosis after treatment with gonadotropin-releasing hormone agonist.

STUDY DESIGN

Fifteen consecutive patients who had undergone gonadotropin-releasing hormone agonist treatment before surgery and 44 patients who did not were studied. The volumes of myomas were determined ultrasonographically, and in patients receiving gonadotropin-releasing hormone agonist therapy measurements were done again after administration of the gonadotropin-releasing hormone agonist to evaluate the response to treatment. Paraffin sections were stained with hematoxylin and eosin, PC 10 for proliferating cell nuclear antigen expression, MIB 1 for measurement of cell proliferation, ApopTag for apoptosis, and factor VIII for quantitation of microvessel density. A deoxyribonucleic acid fragmentation test was also done on nine cases with available frozen tissues.

RESULTS

Most of the leiomyomas showed substantial expression of proliferating cell nuclear antigen. Gonadotropin-releasing hormone agonist therapy further induced significant overexpression of proliferating cell nuclear antigen (p = 0.0004, chi 2 test). All three leiomyomas that failed to respond to therapy showed less proliferating cell nuclear antigen staining compared with the good responders. In contrast, data from MIB 1 immunostaining showed that < 0.3% of leiomyoma cells were proliferating. However, positive-staining cells were more frequently detected in the treatment group (0.075% +/- 0.091% vs 0.002% +/- 0.010%, p = 0.0002, Mann-Whitney U test). Apoptosis developed spontaneously in leiomyoma cells independent of gonadotropin-releasing hormone agonist therapy. No significant change in apoptosis but a significant increase in microvessel density was observed in the treatment group compared with the control group.

CONCLUSION

Enhanced deoxyribonucleic acid damage or repair with cell growth arrest may be responsible for the action of gonadotropin-releasing hormone agonist in shrinking uterine leiomyomas. Moreover, the extent of proliferating cell nuclear antigen expression seems to be associated with the response to gonadotropin-releasing hormone agonist therapy.

Immunolocalization of the pseudorabies virus immediate-early protein IE180 by immunoperoxidase staining

The immediate-early (1E) gene of pseudorabies virus (PRV) expresses immediately upon infection, a phosphorylated protein (immediate-early protein, IE180) that can transactivate viral other genes and plays an essential role in regulating viral gene expression. In order to detect and localize IE180 in infected cells early on, this gene was cloned for overexpression, and the expressed products were applied to generate specific antibodies against IE180 protein. Two recombinant expression plasmids pN and pNB were constructed by cloning the IE gene onto pET 30a(+) expression vector via NcoI and BamHI sites. Plasmid pN contains the 1.8-kb NcoI-NcoI fragment of IE gene coding for the N-terminus of 616 amino acid residues, while pNB contains the 2.8-kb NcoI-Bam HI fragment coding for the rest of the IE180 protein. Both pN and pNB were transformed, respectively, into E. coli cells and produced large amounts of IE protein products during induction with 1 mM IPTG. The expressed IE proteins for pN and pNB were 60 kDa and 100 kDa in size, respectively. These expression products were purified and then used as antigens to immunize mice for preparing specific antibodies against PRV IE180 protein. The specificities of the mice immune sera were confirmed by their abilities to react with IE180 protein present in the PRV infected cells in the Western immunoblotting assay. Furthermore, immunoperoxidase staining of PRV infected cells undertaken with these antisera revealed the subcellular distribution of the IE proteins in the infected cells and also demonstrated their transportation from the cytoplasm to the nucleus during infection.

Immunomodulation in women with endometriosis receiving GnRH agonist

OBJECTIVE

To assess the changes in the subpopulations of lymphocytes and in lymphocyte mitogenic activity in women with endometriosis receiving GnRH-agonist treatment.

METHODS

Twenty-six women with advanced endometriosis from the National Cheng Kung University Medical College were studied. Each received a total of six doses of GnRH agonist at 4-week intervals. Immunologic responses at various times after receiving GnRH-agonist treatment, including numbers of peripheral blood lymphocytes subsets and the lymphocyte proliferative activity, were analyzed using a repeated measures analysis of variance. Twenty-six healthy women who visited our gynecologic clinics for routine Papanicolaou smear examination at the time of the recruitment were enrolled as controls. The responses for each patient receiving GnRH agonist were normalized with respect to those of her matched control at each of the time points. The differences between post- and pretreatment data were estimated using generalized estimating equations.

RESULTS

There was no significant difference in the sizes of lymphocyte subsets between patients and controls before treatment. After GnRH-agonist treatment, there was a trend in the rise of natural killer cell numbers early in the treatment period, with P values of .05 and .07 at 1-2 weeks and 2-3 weeks, respectively. This rise in natural killer cell numbers was not significant until 3-4 weeks and the second month after the treatment. There were no significant changes in the CD4+ and CD8+ T-cell subsets and B cells, although a slight increase in total T cells (ie, CD3+ T) was observed 1-2 weeks after receiving GnRH agonist. The T-cell mitogenic activities at the end of 2 and 4 months after GnRH-agonist treatment were 1.5 and 1.8 times, respectively, of those before treatment.

CONCLUSION

The increase in natural killer cell numbers and the upregulation of T-lymphocyte mitogenic activity, which might be caused by a direct effect of GnRH agonist or a consequence resulting from the depression of estradiol by GnRH agonist, may have implications in the clinical treatment of endometriosis.

Immunomagnetic selection of CD34+ peripheral blood stem cells for autografting in patients with breast cancer

Contamination of transplants with tumour cells may contribute to relapse after peripheral blood stem cell transplantation (PBSCT). We studied the feasibility of CD34+ cell selection from blood-derived autografts obtained following G-CSF-supported cytotoxic chemotherapy in a group of 25 patients with breast cancer (10 with high-risk stage II/III and 15 with stage IV without bone or bone marrow involvement). Using immunomagnetic beads (Isolex 300 SA. Baxter) CD34+ cells were enriched and released by chymopapain resulting in a median purity of 95% (range 82-99%) and a median recovery of 80% (range 27-132%). The enrichment procedure did not change the proportion of CD34+ subsets coexpressing HLA-DR, CD38 and Thy-1, while L-selectin was removed from the cell surface following selection. Using a sensitive immunocytological technique with a cocktail of epithelial-specific antibodies (anti-cytokeratin 8, 18 and 19; HEA125; BM7 and BM8), five leukaphereses products contained epithelial cells, whereas the selected CD34+ cell fraction was free of tumour cells. A neutrophil count of 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l was reached after a median time of 14 and 10d following 40 high-dose chemotherapy (HDC) cycles. Our results indicate that immunomagnetic selection of CD34+ cells yields highly purified autografts devoid of tumour cells whereas the engraftment ability of the progenitor and stem cells is fully retained.

The Xanthomonas campestris gumD gene required for synthesis of xanthan gum is involved in normal pigmentation and virulence in causing black rot

A cloned 4.1-kb EcoRI fragment from Xanthomonas campestris pv. campestris was previously shown to complement the non-mucoid mutant P22 and increase xanthan gum production after being transformed into the wild-type strain Xc17. The gene responsible for these effects was identified, sequenced, and shown to be the gumD gene which has previously been proposed to encode glucose transferase activity, an enzyme required for adding the first glucose residue to the isoprenoid glycosyl carrier lipid during xanthan synthesis. A gumD mutant, isolated from Xc17 by gene replacement, was shown to possess altered pigment xanthomonadin profiles and exhibit reduced virulence in causing black rot in broccoli. This study appears to be the first to demonstrate that interruption of a gene required for xanthan synthesis can lead to reduced virulence of X. campestris.

Refined fetal abdominal growth assessment in normal pregnancy: Part I. Abdominal anteroposterior diameter

BACKGROUND

The assessment of the adequacy of fetal growth by parameters other than the abdominal anteroposterior diameter (AAPD) of the fetus has been studied extensively. However the designs of these studies and the statistical methods used appears to deserve some criticism, based on present knowledge. Noncross-sectional cases selection, uncertainty of the fetal normality and inadequacy in statistical method, mostly ignored the changing property of each standard deviation (SD) of each gestational age (GA) which was proposed by Altman et. al. in 1993, are the three most common flaws in previous publishes. We tried to use AAPD with a strict study design as well as a reasonable statistical method to evaluate the fetal growth.

METHODS

This study was performed in the Division of Maternal Fetal Medicine, National Cheng Kung University Hospital, Taiwan. The prenatal sonographic data of the fetuses were collected prospectively based on the following criteria: (1) accurate dating by knowing the maternal last menstration period (LMP) and early ultrasonography of the fetuses, (2) singleton pregnancy, (3) no fetal structural or chromosomal abnormality confirmed by prenatal ultrasonography and postnatal examination, (4) GA at birth was between 37 and 41 weeks' gestation, (5) no birth asphyxia, (6) appropriate birth body weight, and (7) no maternal medical disease or obstetrical complication which might predictably interfere with fetal growth. The collected data were analyzed by polynomial regression test and the best-fit equation for prediction of fetal growth was selected. The standard deviation (SD) of each GA was modeled before constructing the fetal growth centile charts by Altman's method.

RESULTS

A total of 2077 cross-sectional sonographic data meeting the above criteria were collected for statistical analysis. The best-fit equation for the prediction of fetal GA by AAPD is GA = 20.8539 - 3.36743 x AAPD + 0.86927 x (AAPD)2 - 0.03789 x (AAPD)3 +/- k x [1.2533 x (0.36772 + 0.10938 x AAPD)], (r = 0.97287, p < 0.0001). The best-fit equation for prediction of fetal AAPD by GA is AAPD = -2.49495 + 0.38247 x GA - 1.07071 x 0.001 x (GA)2 +/- k x [1.2533 x (0.01760 + 0.01372 x GA)], r = 0.97122, p < 0.0001. The SD of AAPD for each complete GA was not the same. The fetal growth centile charts in the study are presented in this article.

CONCLUSIONS

The SD of each complete GA changed with each specific GA. The GA of the fetus can be assessed accurately by measuring the AAPD alone. The utilization of these growth centile charts for evaluation of fetal growth is recommended.

V beta 8+CD4-CD8- subpopulation induced by staphylococcal enterotoxin B

Injection of staphylococcal enterotoxin B (SEB) into BALB/c mice induced the depletion of V beta 8+ T-cells which were either V beta 8+CD4+ or V beta 8+CD8+ cells. The CD8 molecule on V beta 8+CD8+ cells was found to decrease at 72 h after SEB treatment while the V beta 8 molecule on V beta 8+ cells or CD4 molecule on V beta 8+CD4+ cells was not affected. Furthermore, a subpopulation of V beta 8+CD4-CD8- T-cells was also induced after SEB-priming. This subpopulation can be found in spleen or lymph nodes. It was small in size and constituted the major part of V beta 8+ cells in lymph nodes at 72 h after SEB-priming. Some of the V beta 8+CD4-CD8- T-cells might be autoreactive because they could be stimulated to proliferative by syngenic mitomycin C-treated splenocytes.

Involvement of hydroxyl radical in the immediate ventilatory responses to inhaled wood smoke in rats

Spontaneous inhalation of wood smoke (approximately 6 ml) via a tracheostomy immediately triggered either a slowing of respiration (SR, n = 51) or an augmented inspiration (AI, n = 32) in 83 anesthetized Sprague-Dawley rats studied. To investigate the involvement of hydroxyl radical (OH.) in evoking these immediate smoke-induced ventilatory responses, smoke challenges were repeated following intravenous infusion (0.05 ml/min for 20 min) of saline vehicle, dimethylthiourea (DMTU, 500 mg/kg), deferoxamine (DEF, 20 mg/kg), or iron-saturated DEF (DEF + Fe, 20 mg/kg). DMTU is a scavenger for OH.. DEF is an iron-chelator which prevents the formation of OH., whereas DEF saturated with iron results in the loss of its iron-chelating properties. In the vehicle group, both the SR (n = 8) and the AI (n = 7) were unaffected by the pretreatment. However, in the DMTU group, the SR (n = 23) was abolished in seven and attenuated in 16 rats, while the AI (n = 10) was eliminated in eight and unaffected in two rats. In the DEF group, the SR (n = 12) was abolished in three and attenuated in nine rats, while the AI (n = 8) was eliminated in six and unaffected in two rats. In contrast, in the DEF + Fe group, both the SR (n = 8) and the AI (n = 7) were not attenuated by the pretreatment. These results suggest that an increase in OH. burden following smoke inhalation is actively involved in evoking the acute irritant effects of wood smoke on breathing in rats.

Lack of evidence for the role of staphylococcal enterotoxins in rheumatoid arthritis

OBJECTIVE

The etiology of rheumatoid arthritis (RA) is not clear. Evidence of limited usage of T cell receptor V beta genes has been found in rheumatoid synovium. Therefore, a pathological mechanism in which superantigens (SAgs) activate T cells with particular T cell receptor V beta chains may exist. However, no direct functional studies of this possible mechanism have yet been reported. In this study we investigated the direct functional responses of lymphocytes from patients with RA to different bacterial superantigens.

METHODS

A primary lymphocyte proliferation test to four different staphylococcal enterotoxins (SEs) was performed in 36 patients with RA to gather information about the relationship between SAg and RA.

RESULTS

The results showed that patients with RA had a decreased proliferative response to all four SEs compared with normal subjects. The decreased response was also found in Con A stimulation. This decreased proliferative response to SEs was not unique to RA patients, but was also observed in patients with systemic lupus erythematosus.

CONCLUSION

We hypothesize that this decreased response to SEs only reflects the generalized immunodeficient status of patients with RA. The results do not suggest that any of the four SEs are involved in the pathogenesis of RA.

Diversity associated with the second expressed HLA-DRB locus in the human population

Although diversity within the HLA-DRB region is predominantly focused in the DRB1 gene, the second expressed DRB loci, DRB3, DRB4, and DRB5, also exhibit variation. Within DRB1(*)15 or DRB1(*)16 haplotypes, four new variants were identified: 1) two new DRB5 alleles, DRB5*0104 and DRB5*0204, 2) a haplotype carrying a DRB1(*)15 or *16 allele without the usual accompanying DRB5 allele, and 3) a haplotype carrying a DRB5(*)0101 allele without a DRB1(*)15 or *16 allele. The evolutionary origins of these haplotypes were postulated based on their associations with the DRB6 pseudogene. Within HLA haplotypes which carry DRB3, a new DRB3(*)0205 allele and one unusual DRB3 association were identified. Finally, two new null DRB4 alleles are described: DRB4(*)0201N, which exhibits a deletion in the second exon, and a second allele, DRB4(*)null, which lacks the second exon completely. Gene conversion-like events and variation in the number of functional genes through reciprocal recombination and inactivation contribute to the diversity observed in the second expressed HLA-DRB loci.

6-Hydroxydopamine induces thymocyte apoptosis in mice

6-Hydroxydopamine (6-OHDA) induces degeneration of noradrenergic nerves and has been shown to alter the immune responses. In this study, intraperitoneal administration of 6-OHDA induces mouse thymus atrophy. The lowest levels of thymus weight and cell number were reached at days 3 and 5 in mice receiving 6-OHDA treatment; they gradually recovered thereafter. On flow cytometry analysis, the most substantial reductions were recorded for CD4+CD8+ thymocytes, although the numbers of other subpopulations, i.e. CD4+CD8-, CD4-CD8+ and CD4-CD8- cells were also reduced. DNA fragmentation, a characteristic of apoptosis, was detected in the thymocytes following 6-OHDA injection. Pretreatment with desipramine greatly blocked the reduction in thymus size and thymocyte number, the changes in thymocyte subpopulations, the percentage of subdiploid (apoptotic) cells and the appearance of DNA fragmented bands. Furthermore, 6-OHDA-induced thymocyte apoptosis could also be detected in vitro, and was blocked by desipramine treatment. These results indicate that 6-OHDA induces mouse thymocytes to undergo apoptosis both in vivo and in vitro, and this effect is inhibited by catecholamine uptake blocker.

Human cytomegalovirus immediate-early protein IE2 tethers a transcriptional repression domain to p53

The IE2 gene of human cytomegalovirus has been implicated in the development of coronary restenosis, and the gene product appears to inhibit p53-dependent transactivation. Here we describe an analysis of the IE2-p53 interaction. Repression of p53 function by IE2 requires two separable domains of IE2. The N terminus of IE2 interacts with p53. IE2 has little effect on the ability of p53 to bind specific DNA sequences. Reduction of the transactivation activity of p53 is caused by a transcriptional repression function contributed by the C-terminal domain of IE2. These findings suggest that IE2 may function as a transcriptional repressor, which is recruited to p53's target genes by interacting with p53.

In vivo analysis of a superantigen-induced T cell suppressor factor

We have previously reported that the superantigen staphylococcal enterotoxin B (SEB) was able to suppress an immune response to sheep red blood cells when administered intravenously to mice. While the capacity of the superantigens to stimulate lymphocytes and accessory cell functions has been thoroughly examined, it is clear that these agents may also exhibit potent immunosuppressive activity both in vivo and in vitro. This SEB-induced immunosuppression was determined by our laboratories to be mediated by a population of T suppressor cells. The suppression may be due to the generation of inhibitory lymphokines, including IL-10 or transforming growth factor beta, following superantigen stimulation. Alternatively, the immunomodulatory activity may be due to the activation of antigen-specific and/or genetically restricted suppressor cells by SEB. The mechanism of activity of these suppressor cells has not been fully defined. In this report we wished to determine whether a suppressor factor generated from SEB-activated T cells in vitro may be responsible for the inhibition of antibody or delayed-type hypersensitivity responses in vivo. We observed that both antibody and delayed-type hypersensitivity responses were inhibited following administration of the SEB-induced suppressor factor. The in vivo inhibitory activity of the SEB-induced suppressor factor was found to be genetically restricted at the "I-J" locus. In addition, monoclonal anti-I-J antibodies recognized the suppressor factor in a haplotype-specific fashion. These results show that the suppressive product of SEB-induced T cells possesses the ability to inhibit, in a genetically restricted fashion, both cellular and humoral immune responses.

Comparison of N-acetylcysteine and methylene blue, alone or in combination, for treatment of acetaminophen toxicosis in cats

Acetaminophen is widely used in human beings for analgesic purposes, but is one of the most frequent causes of poisoning in cats. Acetaminophen-poisoned cats develop methemoglobinemia and sometimes hepatic failure. To determine the benefit of using methylene blue, a treatment for methemoglobinemia, along with N-acetylcysteine (NAC), the recommended treatment for acetaminophen-poisoned cats, groups of 3 male and 3 female cats each were given methylene blue NAC, or both after administration of acetaminophen (120 mg/kg of body weight, PO). Male cats seemed more susceptible than female cats to acetaminophen toxicosis, because 3 males died of hepatic failure (2 cats given acetaminophen/methylene blue and 1 given acetaminophen/NAC/methylene blue). Although NAC alone seemed to elicit the best overall response, methylene blue, alone or in combination with NAC, may be useful in female cats.

A movable and regulable inactivation function within the central region of a temperature-sensitive p53 mutant

p53 is the most frequently mutated gene in human cancer. Naturally occurring mutations of p53 are mainly located within a region containing residues 100-300 and are predominantly of missense type, resulting in loss of the protein's DNA binding activity. Here we show that this type of mutation also represses the p53 N-terminal activation domain. The repression activity is localized in the central region of mutant p53 containing residues 101-318. Interestingly, the central region of a temperature-sensitive mutant p53N247I possesses a movable and regulable inactivation function. It represses other activities present on the same polypeptide chain without strict regard to the configuration of that polypeptide only at the nonpermissive temperature (37 degrees C) and not at the permissive temperature (30 degrees C). Furthermore, this mutant p53 region exhibits no other activity, and its function is independent of endogenous p53 status.

Prediction of early pregnancy outcomes

OBJECTIVE

A prospective study was performed on the conception hormones of early pregnancy in order to examine their sensitivity and predictability for early pregnancy loss.

METHODS

The serum levels of progesterone, estradiol and human chorionic gonadotropin (hCG) were measured and analyzed at 5-8 weeks of gestation in pregnancies occurring both with and without ovarian stimulation.

RESULTS

If a level of < 10 ng/ml of progesterone was chosen as the cut-off value for the prediction of early pregnancy loss, the sensitivity and specificity were 56% and 98%, respectively. The optimal cut-off value was chosen at < 0.5 multiples of the median (MoM) and < 0.4 MoM for estradiol and hCG, respectively. This gave a sensitivity of 80% for estradiol and 85% for hCG, and a specificity of 93% for estradiol and 81% for hCG at week 8 of gestation.

CONCLUSION

The combined determination of conception hormones is an efficacious method of monitoring early pregnancy and may be used for predicting outcome.

Changes of protein kinase C subspecies in staphylococcal enterotoxin-B-induced thymocyte apoptosis

Our previous studies demonstrated that intravenous administration of staphylococcal enterotoxin B (SEB) to BALB/c mice resulted in thymocyte apoptosis. In the present study, we evaluated the role of protein kinase C (PKC) in thymocyte apoptosis induced by SEB. Our results showed that the level of protein phosphorylation in the thymocytes was reduced after the in vivo SEB treatment for 24 h. The activity of classical PKC subspecies was decreased in both cytosolic and membrane fractions of thymocytes following SEB administration. The lowest level of PKC activity was reached by 24 and 48 h, then was recovered gradually after 72 h. Furthermore, the mRNA expression of PKC-beta and, to a much less extent, PKC-alpha, but not PKC-sigma, in thymocytes was reduced by SEB. The decrease of mRNA level of PKC-beta showed good correlation with the pattern of PKC activity. These results provide direct evidence showing the changes in PKC subspecies mRNA expression during the process of apoptosis.

Intravaginal foreign body retained for a long duration

An intravaginal foreign body of long duration can pose a diagnostic dilemma, since a number of diagnostic modalities may fail to detect its existence. We present the case of an 8-year-old girl who suffered from a bloody, malodorous vaginal discharge for over 4 years, during which time she had been evaluated by several gynecologists. A vaginal examination performed under analgesia revealed a pinpoint-sized opening 2 cm above the hymen. We inserted a cannula and injected radio-opaque contrast medium. An intravaginal filling defect was visible, which strongly suggested the presence of a foreign body. An incision through this scarred area was performed and two foreign bodies, one shaped like a plastic tube and the other a cap, were removed. We conclude that vaginography may provide an alternative diagnostic tool for this condition.

A role for activator-mediated TFIIB recruitment in diverse aspects of transcriptional regulation

BACKGROUND

Transcription by RNA polymerase II in eukaryotic cells requires the ordered assembly of general transcription factors on the promoter to form a preinitiation complex. Transcriptional activator proteins (activators) stimulate transcription by increasing the rate and/or extent of preinitiation complex assembly. We have shown previously that acidic activators increase the stable association of TFIIB on the promoter, a process we refer to as 'recruitment'. In this study, we provide evidence that diverse activators facilitate TFIIB assembly by a related mechanism. We then investigate the activator-mediated assembly of TFIIB with regard to two aspects of transcription: the distance-dependence of activator function, and reinitiation.

RESULTS

We have previously described amino-acid-substitution mutants of TFIIB that are able to support an activator-independent basal level of transcription but do not respond to acidic activators. We now show that these mutants also do not respond to other classes of activators. We demonstrate that this defect is due to a failure of the activators to recruit the mutant TFIIB to the promoter. Activators often lose activity as their distance from the initiation site is increased. We show that this impaired transcriptional activity correlates with a decrease in TFIIB recruitment. Finally, we find that following the initiation of transcription, TFIIB dissociates from the promoter, requiring the activator-mediated reassembly of TFIIB in the preinitiation complex for each new round of transcription.

CONCLUSION

We have provided evidence that diverse activators recruit TFIIB to the promoter by a related mechanism. This central step in transcriptional activation is sensitive to promoter architecture, and is required for each new round of transcription.

Comparative study of the mammalian liver innervation: an immunohistochemical study of protein gene product 9.5, dopamine beta-hydroxylase and tyrosine hydroxylase

The liver innervation of eight different mammalian species was examined by immunohistochemical localization of protein gene product (PGP) 9.5 to visualize the general innervation for autonomic nerve fibres. In addition, dopamine beta-hydroxylase (DBH) and tyrosine hydroxylase (TH), two enzymes involved in catecholamine synthesis, were localized immunohistochemically to delineate hepatic sympathetic nerve fibres. We found that: (1) Within the interlobular region of each species, PGP 9.5, DBH and TH-positive nerve fibres were all seen in close association with branches of hepatic arteries, portal veins and bile ducts. (2) Within the parenchyma of the guinea-pig, cat, dog, pig, monkey and human liver, the presence of the three immuno-positive nerve fibres could be unequivocally identified, although the density of these intralobular fibres showed marked species variation. Moreover, immunoelectron microscopic study confirmed that PGP 9.5-positive nerve terminals of the human liver are in close apposition to hepatocytes. (3) In mouse and rat, no parenchymal nerve fibres immunoreactive for PGP 9.5, TH or DBH could be demonstrated.

Transcriptional regulation by p53. Functional interactions among multiple regulatory domains

The tumor suppressor p53 protein possesses activities typical of eukaryotic transcriptional activators; p53 binds to specific DNA sequences and stimulates transcription of the target genes. By a series of deletion and domain-swapping studies, we report here that (i) p53 has two auxiliary domains, which have little effect on the DNA binding activity of its core domain but are capable of modulating its transactivation activity in a target site-dependent manner; (ii) p53 contains two cell-specific transcriptional inhibitory domains, I1 and I2, which are active in Saos-2 and HeLa cells but not in HepG2 and Hep3B cells; and (iii) I1 inhibits the activity of several structurally different activating regions. These results demonstrate that the apparent transcriptional activity of p53 is determined by collaborations among its regulatory domains, its target sites, and the cellular environment.

Immunomodulatory effects of acute exercise bout in sedentary and trained rats

The immune response to acute exercise after long-term training was evaluated in rats. After 10 wk of exercise training on a drum exerciser, both sedentary control and trained groups ran with the intensity of 70% of peak oxygen consumption (VO2peak) for 10 min immediately before sacrifice. The mitogenic activity of spleen lymphocytes in trained group to staphylococcal enterotoxin B, a polyclonal T cell activator, decreased as compared to the sedentary control following acute exercise. However, proliferative response to lipopolysaccharide, a B cell mitogen, was augmented. Furthermore, the interleukin-2 production was reduced in the trained group. The lymphocyte subpopulations in the spleen and the peripheral blood lymphocytes were analyzed by flow cytometry. Although the tendency of changes in some populations was observed in trained vs untrained groups, no statistically significant difference was manifested. The serum levels of both norepinephrine and epinephrine increased immediately after acute exercise. The increase in serum lactate concentration was observed following acute exercise in sedentary control, but less prominent in the trained group.