[Vascular anastomoses in free jejunal reconstruction to the neck vessels: an experience of consecutive 20 cases without using surgical microscope]

Twenty consecutive cases of pharyngoesophageal cancer who underwent free jejunal reconstruction were reported. The common carotid or external carotid artery was used for a feeder of the free graft. The internal jugular vein were served as a drainage vein. All anastomoses were performed in an end-to-side fashion without using surgical microscopes. Mean carotid artery clamping time was 16 minutes and no neurological complications were noticed postoperatively. Graft failure was occurred in 1 patient. The presenting technique, showing 95% success rate, is recommended as a simple option for vascular anastomosis in free jejunal reconstructive surgery.

[The synthesis and spectral study of multicomponent heteropoly compounds with Keggin structure]

The Multicomponent heteropoly compounds [Me4N]3 + x[PVxMoyW12-x-yO40]. n(H2O) with Keggin structure have been synthesized, and have been characterized by FTIR and NIR FT-Raman. The vibrational regularity of oxygen-containing bonds (P-Oa, M = Od, M-Ob-M and M-Oc-M) in these heteropoly compounds have been studied. The vibrational frequencies nu as (M = Od) and nu as (M-Ob-M) was shown to prove the reason why the acidity of the heteropoly compounds descended and the oxidization increased by the substitution of V atoms.

[Synthesis and spectroscopic studies of the oxothio heteropolyanion of [PMo9V3O40]6-]

Some compounds were obtained through addition H2S to the heteropoly-compound (NH4)4H2[PMo9V3O40].10H2O in dimethyformamide. The FTIR spectrum and NIR FT-Raman spectrum of these compounds were investigated. The spectroscopic studies of the compound II showed that it is a oxothio heteropoly-compound.

Sexual and fertility behaviors of American females aged 15-19 years: 1985, 1990, and 1995

OBJECTIVES

This study characterized changes in sexual and reproductive behaviors from 1985 through 1995 among American females aged 15 to 19 years and related these changes to family factors.

METHODS

Nationally representative sample survey data from the 1995 National Survey of Family Growth were analyzed with Weibull hazards models of age at first intercourse and first pregnancy and with logistic regression models of contraceptive use at first intercourse and pregnancy outcome.

RESULTS

Improvements in the family socioeconomic situations of young women have lessened the risk of teen motherhood, while changes in family structure have increased the risk. Young women whose parents have more than a high school education, who live with both parents, and who attend church delay the timing of first sexual intercourse and are more likely to use a contraceptive.

CONCLUSIONS

The trend of increases in teenage motherhood has ended owing to a halt in increases in the proportion of sexually active young women and substantial improvement in contraception, with the greatest improvements among those from advantageous family situations.

Cluster monte carlo study of multicomponent fluids of the stillinger-helfand and widom-rowlinson type

Phase transitions of fluid mixtures of the type introduced by Stillinger and Helfand are studied using a continuum version of the invaded cluster algorithm. Particles of the same species do not interact, but particles of different types interact with each other via a repulsive potential. Examples of interactions include the Gaussian molecule potential and a repulsive step potential. Accurate values of the critical density, fugacity, and magnetic exponent are found in two and three dimensions for the two-species model. The effect of varying the number of species and of introducing quenched impurities is also investigated. In all the cases studied, mixtures of q species are found to have properties similar to q-state Potts models.

Effects of growth hormone and prolactin on hematopoiesis

The use of the neuroendocrine hormones growth hormone (GH) and prolactin (PRL) in preclinical models, demonstrating promotion of hematopoietic recovery and immune function, offers promise for several clinical situations. These hormones do not appear to produce the same extent of immune/hematopoietic effects when compared to conventional hematopoietic and immune stimulating cytokines (i.e. G-CSF or interleukin-2). However, their pleiotropic effects and limited toxicity after systemic administration makes them attractive to test in myeloablative situations. More work needs to be performed to understand the mechanism(s) of GH and PRL action, particularly with regard to hematopoietic progenitor cell expansion and differentiation both in normal and pathologic situations.

Characterisation of tribochemically assisted bonding of composite resin to porcelain and metal

OBJECTIVE

The fracture of bonded ceramic to metal restorations remains a problem in clinical dental practice. The use of resin based composites to repair such fractures is generally unsatisfactory. Tribochemical technology creates a surface layer of small silica particles fused to the surface substrate. Such a layer potentially improves adhesion of resin to both alloy and porcelain. Adhesion between two substrates is traditionally studied using shear or tensile bond strength tests. However, the highest stress at bond failure may not represent the real bonding characteristics correctly. An alternative method is to describe the bonding characteristics by determining the strain energy release rate for a given interface. This study compares the bonding characteristics of a resin to gold/porcelain interface using a tribochemical coating process with those of a control group using simple gritblasting.

METHODS

Pre-cracked specimens were subjected to load-unload cycles using a simple four point bending test and the resultant strain energy release rates were calculated.

RESULTS

Tribochemically pretreating the porcelain resulted in a significant increase in the resultant strain energy release rate from 42.72+/-3.65J/m(2) for the controls to 61.35+/-6.26J/m(2). Likewise there was a significant improvement in the strain energy release rate for the gold/composite interface from 27.31+/-3.00J/m(2) to 42.13+/-4.83J/m(2).

CONCLUSIONS

Tribochemical technology offers significant potential advantages for clinical dental practice.

Accuracy and predictability of intraocular lens power calculation after photorefractive keratectomy

PURPOSE

To investigate the accuracy and predictability of intraocular lens (IOL) power calculation in postoperative photorefractive keratectomy (PRK) eyes.

SETTING

Gimbel Eye Centre, Calgary, Alberta, Canada.

METHODS

The results in 5 cataract surgery eyes that had had PRK were analyzed retrospectively. Target refractions based on actual and refraction-derived keratometric values were compared with postoperative achieved refractions. The target refractions calculated using 5 IOL formulas and 2 A-constants were also compared with the achieved refractions.

RESULTS

In postoperative PRK eyes, the power calculation was more accurate and predictable when the smaller of either the actual or refraction-derived keratometric value was used to calculate the IOL power. The difference between target and achieved refractions appeared smaller when the Binkhorst formula was used. No significant hyperopic shift was observed after cataract surgery.

CONCLUSION

The smaller of the actual or the refraction-derived keratometric value is recommended for calculating IOL power in post-PRK eyes.

Experience with PCR screening

The COBAS AmpliScreen Hepatitis C (HCV) Test, Version 2.0, which is designed for screening pools composed of samples from individual units of blood or plasma, employs a MultiPrep sample processing procedure that simultaneously extracts and concentrates HCV, HIV-1 and Hepatitis B virus particles from plasma. An HCV Internal Control (IC) RNA serves as an extraction and amplification control for each independently processed sample. Processed samples are amplified by RT-PCR using HCV-specific complementary primers and detected by hybridization of the amplified products to HCV- and IC-specific oligonucleotide probes. The analytical sensitivity of the test is 25 International Units (IU) of HCV per mL of pooled plasma; all HCV genotypes are detected with similar efficiency. The test detected HCV RNA 23 to 32 days prior to anti-HCV antibody seroconversion for four of the five seroconversion panels tested. The test had sufficient sensitivity to reproducibly detect a single infected unit containing 2.4 x 10(3) copies of HCV per mL in a pool with 23 uninfected units. COBAS AmpliScreen tests for HIV-1 and HBV now being validated by Roche Molecular Systems also incorporate the MultiPrep specimen processing method, thereby making it possible to use a single processed specimen to screen for all three viruses.

Inhibition of adhesion of Escherichia coli k88ac fimbria to its receptor, intestinal mucin-type glycoproteins, by a monoclonal antibody directed against a variable domain of the fimbria

Strains of enterotoxigenic Escherichia coli that express K88 fimbriae are among the most common causes of diarrhea in young pigs. Adhesion of bacteria to receptors on intestinal epithelial cells, mediated by K88 fimbriae, is the initial step in the establishment of infection. Three antigenic variants of K88 fimbriae exist in nature: K88ab, K88ac, and K88ad. K88ac is the most prevalent and may be the only variant of significance in swine disease. Each K88 fimbrial variant is composed of multiple antigenic determinants. Some of these determinants are shared among the three variants and may be referred to as conserved epitopes, whereas others are unique to a specific variant and may be referred to as variable epitopes. In this study, monoclonal antibodies (MAbs) specific to either variable or conserved epitopes of K88ac fimbriae were produced. The specificity of each MAb was tested by enzyme-linked immunosorbent and immunoblot assays. Fab fragments were prepared from these MAbs and were tested for their ability to block the binding of K88-positive bacteria and purified fimbriae to porcine enterocyte brush border vesicles and purified K88 receptors, respectively. The purified receptors were intestinal mucin-type sialoglycoproteins (IMTGP) isolated from porcine enterocytes (A. K. Erickson, D. R. Baker, B. T. Bosworth, T. A. Casey, D. A. Benfield, and D. H. Francis, Infect. Immun. 62:5404-5410, 1994). Fab fragments prepared from MAbs specific for variable epitopes blocked the binding of bacteria to brush borders and of fimbriae to IMTGP. However, those from MAbs specific for a conserved epitope did not. These observations indicate that the receptor-binding domain of a K88ac fimbria is contained, at least in part, within the antigenically variable epitopes of that fimbria. Epitope mapping for one of the MAbs, which recognizes a linear epitope on K88ac fimbriae, indicated that this MAb binds to the region from amino acid no. 64 to no. 107 on the major subunit of K88ac fimbriae.

Application of membrane-based dendrimer/DNA complexes for solid phase transfection in vitro and in vivo

In this study a general description of the use of solid support membranes as the device for DNA delivery mediated by PAMAM dendrimers is presented. In contrast to the other DNA carriers, dendrimer/DNA complexes retain the ability to transfect after drying, which enabled coating or incorporation of complexes into poly(DL-lactide-co-glycolide) or collagen-based bioerodable membranes. These studies provide support for the use of this technology for in vitro and in vivo transfection of skin cells. Expression of luciferase or green fluorescent protein from pCF1-Luc and pEGFP1 plasmids indicated that dendrimer/DNA complexes can mediate transfection after dissociation from the solid support and/or when retained on the surface of the membranes. Modification of the membranes by incorporation of an anionic lipid, phosphatidyl glycerol (PG) at 1-5% concentrations, resulted in more efficient in situ transfection, particularly with dendrimer/DNA complexes formed at the low charge ratios (1-5). We also report data supporting the feasibility of membrane-based dendrimer/DNA complexes, particularly formed at lower than neutralizing conditions, for topical in vivo delivery of DNA to hairless mouse skin.

Characterization and esterification of hemicelluloses from rye straw

Hemicelluloses were extracted with 10% KOH/0.5% Na(2)B(4)O(7). 10H(2)O from delignified rye straw. Esterification of the hemicelluloses with various acyl chlorides was performed in a homogeneous N,N-dimethylformamide and lithium chloride system using 4-(dimethylamino)pyridine catalyst and triethylamine as a neutralizer. The degree of substitution was controlled between 0.37 and 1.65. Under an optimum condition (sample 14, molar ratio 3:1), >90% of the free hydroxyl groups in native hemicelluloses were stearoylated at 75 degrees C for 40 min. Meanwhile, the products were characterized by FT-IR and GPC techniques as well as their solubilities. The molecular mass measurements (31400-123300 g mol(-)(1)) showed only a minimal degradation of the macromolecular hemicelluloses during rapid reactions at 48-75 degrees C for 20-40 min.

Rta of murine gammaherpesvirus 68 reactivates the complete lytic cycle from latency

Herpesviruses are characterized as having two distinct life cycle phases: lytic replication and latency. The mechanisms of latency establishment and maintenance, as well as the switch from latency to lytic replication, are poorly understood. Human gammaherpesviruses, including Epstein-Barr virus (EBV) and human herpesvirus-8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), are associated with lymphoproliferative diseases and several human tumors. Unfortunately, the lack of cell lines to support efficient de novo productive infection and restricted host ranges of EBV and HHV-8 make it difficult to explore certain important biological questions. Murine gammaherpesvirus 68 (MHV-68, or gammaHV68) can establish de novo lytic infection in a variety of cell lines and is also able to infect laboratory mice, offering an ideal model with which to study various aspects of gammaherpesvirus infection. Here we describe in vitro studies of the mechanisms of the switch from latency to lytic replication of MHV-68. An MHV-68 gene, rta (replication and transcription activator), encoded primarily by open reading frame 50 (ORF50), is homologous to the rta genes of other gammaherpesviruses, including HHV-8 and EBV. HHV-8 and EBV Rta have been shown to play central roles in viral reactivation from latency. We first studied the kinetics of MHV-68 rta gene transcription during de novo lytic infection. MHV-68 rta was predominantly expressed as a 2-kb immediate-early transcript. Sequence analysis of MHV-68 rta cDNA revealed that an 866-nucleotide intron 5' of ORF50 was removed to create the Rta ORF of 583 amino acids. To test the functions of MHV-68 Rta in reactivation, a plasmid expressing Rta was transfected into a latently infected cell line, S11E, which was established from a B-cell lymphoma in an MHV-68-infected mouse. Rta induced expression of viral early and late genes, lytic replication of viral DNA, and production of infectious viral particles. We conclude that Rta alone is able to disrupt latency, activate viral lytic replication, and drive the lytic cycle to completion. This study indicates that MHV-68 provides a valuable model for investigating regulation of the balance between latency and lytic replication in vitro and in vivo.

Dihydrofolate reductase from Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is the first human virus known to encode dihydrofolate reductase (DHFR), an enzyme required for nucleotide and methionine biosynthesis. We have studied the purified KSHV-DHFR enzyme in vitro and analyzed its expression in cultured B-cell lines derived from primary effusion lymphoma (PEL), an AIDS-associated malignancy. The amino acid sequence of KSHV-DHFR is most similar to human DHFR (hDHFR), but the viral enzyme contains an additional 23 amino acids at the carboxyl-terminus. The viral DHFR, overexpressed and purified from E. coli, was catalytically active in vitro. The K(m) of KSHV-DHFR for dihydrofolate (FH(2)) was 2.4 microM, which is significantly higher than the K(m) of recombinant hDHFR (rhDHFR) for FH(2) (390 nM). K(m) values for NADPH were similar for the two enzymes, about 1 microM. KSHV-DHFR was inhibited by folate antagonists such as methotrexate (K(i): 200 pM), aminopterin (K(i): 610 pM), pyrimethamine (K(i): 29 nM), trimethoprim (K(i): 2.3 microM), and piritrexim (K(i): 3.9 nM). In all cases, K(i) values for these folate antagonists were higher for KSHV-DHFR than for rhDHFR. The viral enzyme was expressed at levels two- to tenfold higher than hDHFR in PEL cell lines as an early lytic cycle gene. KSHV-DHFR mRNA and protein appeared from 6 to 24 h after chemical induction of the KSHV lytic cycle. Epitope-tagged KSHV-DHFR and rhDHFR both localized to the nucleus of transfected cells, while other KSHV nucleotide metabolism genes localized to the cytoplasm. DHFR activity was not essential for viral replication in cultured PEL cells. Since hDHFR was not detectable in peripheral blood mononuclear cells (PBMCs), KSHV-DHFR may function to provide increased DHFR activity in vivo in infected cells that have little or none of their own enzyme.

Balance of mass, momentum, and energy in splintering central collisions for 40Ar up to 115 MeV /Nucleon

For central collisions of (17-115)A MeV 40Ar+Cu, Ag, Au, an overall balance is determined for the average mass, energy, and longitudinal momentum. Light charged particles and fragments are separated into forward-focused and isotropic components in the frame of the heaviest fragment. Energy removal by the isotropic component reaches 1-2 GeV. For such high deposition energies, statistical multifragmentation models predict much more extensive nuclear disassembly than is observed.

Immunological effects of BCG as an adjuvant in autologous tumor vaccines

The role of Bacillus Colmette-Guérin (BCG) as an adjuvant in autologous tumor vaccines was examined. In nine patients with renal cell cancer, irradiated tumor cells alone (wild-type, WT) or with BCG were inoculated intradermally into contralateral thighs. Seven to 10 days later, the draining vaccine-primed lymph nodes (WT-VPLN and BCG-VPLN) were excised. BCG increased the number of harvested VPLN cells by 10-fold (mean +/- SE = 61.8 +/- 20.6/x10(-7)/patient). BCG-VPLN had significantly greater percentages of CD3(+) and CD4(+) T cells compared to WT-VPLN. Both groups of VPLN cells were activated in vitro with anti-CD3 or anti-CD3/CD28 mAbs followed by expansion in IL-2. Anti-CD3/CD28 activation resulted in greater expansion of CD4(+) T cells compared to anti-CD3. After activation, VPLN cells were stimulated with irradiated autologous tumor targets and cytokines (IFN-gamma, GM-CSF, IL-10) released into the supernatants were measured 24 h later. Anti-CD3/CD28-activated BCG-VPLN cells were found to have a greater release of IFN-gamma compared with that of WT-VPLN cells, which was not observed significantly with IL-10 or GM-CSF. BCG resulted in increased VPLN cell yield as well as enhanced type 1 (IFN-gamma release) immune responses of VPLN cells to autologous tumor without upregulating type 2 (IL-10 release) responses. Anti-CD3/CD28 was superior to anti-CD3 activation in this cellular response.

Refractive error in cataract surgery after previous refractive surgery

Bilateral cataract extraction with posterior chamber intraocular lens (IOL) implantation was performed in a patient after previous photorefractive keratectomy, radial keratotomy (RK) combined with astigmatic keratotomy, and retreatment of RK. Significant hyperopic error was observed after cataract surgery, and the IOLs were eventually exchanged in both eyes. A review of this case found that the refractive error was smaller when a refraction-derived keratometric value was selected for IOL power calculation. Nevertheless, hyperopic error still occurred.

[Colorectal cancer: lymphatic metastasis and choice of operation]

OBJECTIVE

To study lymphatic metastasis of colorectal cancer for deceding the of dissection extent of dissection.

METHODS

Six hundred and twenty-three lymph nodes from 74 cases of colorectal cancer were analyzed after D(3) resection. They were classified into peritumor, longitudinal spread, and upward spread groups. The metastasis rate of lymph node and its incidence were calculated.

RESULTS

The metastasis rate of lymph node and its incidence in the peritumor, longitudinal spread, and upward spread (N(2) and N(3)) groups were 47.2% and 38.6%, 22.8% and 18.6%, and 29.7% (20.3% and 9.4%) and 10.2% (19.0% and 5.3%), respectively. The distribution rate of metastatic lymph node was 61.2%, 17.1%, and 21.6% in the peritumor, longitudinal spread, and upward spread groups, respectively. Within 2.0 cm on the anal side of rectal cancer, the metastasis rate was 3.7%, whereas in 2.0 - 4.0 cm no metastasis was observed cancer at the lower part of the rectum demonstrated a higher lateral metastasis rate.

CONCLUSIONS

Colorectal cancer tends to metastasize to longitudinal and the risk of metastasis increased in the stage of pT(3) and pT(4) or low differentiation stage. Jump metastasis is also a feature. D(3) radical resection is necessary for colorectal cancer, but extended lateral lymph node needs enectomy or total mesorectal excision. No residual tumor tissue exists at the anastomosis site after low anterior resection when the excision distance is beyond 2.0 cm from the anal margin of rectal cancer.

[Effect of gui xin tong on sorbitol and nerve conduction velocity in diabetic rats]

OBJECTIVE

To investigate the effect of Gui Xin Tong(GXT) on sorbitol and nerve conduction velocity in diabetic rats.

METHOD

The model rats suffering from diabetes were induced by STZ, and blood sugar levels above 16 mmol/L were chosen for observation. The rats were divided into GXT group, AG group and control group. The nerve conduction velocity, aldose reductase activity and sorbitol in STZ induced diabetic rats were investigated.

RESULT

Compared with the control group GXT could increase the sciatic nerve conduction velocity significantly (P < 0.05), decrease the RBC and sciatic nerve, aldose reductase activity, and RBC-sorbitol content.

CONCLUSION

GXT has the effect of improving nerve conduction velocity significantly and reducing aldose reductase activity and sorbitol

Performance characteristics of the AmpliScreen HIV-1 test, an assay designed for screening plasma mini-pools

This study evaluated the performance characteristics of the AmpliScreen(TM)Human Immunodeficiency Virus-Type 1 (HIV-1) Test, Version 1.5, a test designed for screening pools composed of samples from individual units of blood or plasma. HIV-1, hepatitis C (HCV) and hepatitis B (HBV) virus particles were simultaneously extracted and concentrated from plasma by a multi-prep sample processing procedure. An HIV-1 Internal Control (IC) RNA was added to each sample to serve as an extraction and amplification control. Processed samples were amplified by RT-PCR using HIV-1-specific complementary primers and detected by hybridization of the amplified products to HIV-1- and IC-specific oligonucleotide probes. The analytical sensitivity of the test (concentration that yields >/=95% positive results in a set of replicate tests) was 25 copies of HIV-1 RNA per mL of pooled plasma. Representative strains from all HIV-1 group M subtypes were reproducibly detected (>95% positive results among 22 replicate tests) at concentrations of 30 to 75 viral particles per ml. The test exhibited excellent specificity; it did not cross-react with a set of 30 viral and five bacterial isolates and yielded negative results on a panel of 500 blood samples from HIV-1 seronegative donors. Samples containing abnormally high levels of haemoglobin, albumin, triglycerides or bilirubin in plasma samples did not interfere with the detection of HIV-1 RNA at a concentration of 100 copies of per ml. The test detected HIV-1 RNA 7-17 days prior to anti-HIV-1 antibody seroconversion for all 10 seroconversion panels tested. A fully automated COBAS AmpliScreen(TM)version of this test is being validated. COBAS AmpliScreen tests for HCV and HBV also incorporate the multi-prep specimen processing method, thereby making it possible to use a single processed specimen to screen for all three viruses.

Accounting for the computational basis of consciousness: a connectionist approach

This paper argues for an explanation of the mechanistic (computational) basis of consciousness that is based on the distinction between localist (symbolic) representation and distributed representation, the ideas of which have been put forth in the connectionist literature. A model is developed to substantiate and test this approach. The paper also explores the issue of the functional roles of consciousness, in relation to the proposed mechanistic explanation of consciousness. The model, embodying the representational difference, is able to account for the functional role of consciousness, in the form of the synergy between the conscious and the unconscious. The fit between the model and various cognitive phenomena and data (documented in the psychological literatures) is discussed to accentuate the plausibility of the model and its explanation of consciousness. Comparisons with existing models of consciousness are made in the end.

Photorefractive keratectomy in keratoconus suspects

PURPOSE

To compare the refractive outcome after photorefractive keratectomy (PRK) in keratoconus-suspect patients with that in patients with normal corneal topography.

SETTING

Gimbel Eye Centre, Calgary, Alberta, Canada.

METHOD

In a retrospective study, 3 patients (5 eyes) with unusually shaped corneal topography before surgery were selected as keratoconus suspects. Corneal topography (inferior-superior [I-S] value, central corneal power, and central power difference between both eyes), preoperative and 1 year postoperative refraction, and visual acuity in the keratoconus suspects were compared with those in a control group.

RESULTS

The mean preoperative I-S value was 1.79 diopters (D) in the keratoconus-suspect eyes and 0.35 D in the control group eyes (P = .0001). The I-S value of individual corneas in the keratoconus suspects was more than 2 standard deviations above the mean in the control group except in 1 eye in which the steepened area was located in the central cornea. The central power difference between the eyes of this patient was 3.60 D, which was significantly higher than that in the control group. The refractive outcomes in the keratoconus suspects were comparable to those in the control group.

CONCLUSION

In this study, the refractive outcomes after PRK in the keratoconus suspects and controls were comparable. However, further investigation with a larger sample and longer follow-up is needed.

Simultaneous extraction of hepatitis C virus (HCV), hepatitis B virus, and HIV-1 from plasma and detection of HCV RNA by a reverse transcriptase-polymerase chain reaction assay designed for screening pooled units of donated blood

BACKGROUND

Testing for viral nucleic acids should reduce the residual risk of transmitting viral infections by transfusion of blood components. The AmpliScreen Hepatitis C (HCV) Test, Version 2.0, was designed for screening pools composed of samples from individual units of blood or plasma.

STUDY DESIGN AND METHODS

An ultracentrifugation step during sample processing simultaneously extracts and concentrates HCV, HIV type 1, and hepatitis B virus particles from plasma. An HCV internal control RNA serves as an extraction and amplification control for each processed sample. Processed samples are amplified by reverse transcriptase polymerase chain reaction and detected by hybridization of the amplified products to HCV- and internal-control-specific oligonucleotide probes. Plasma samples containing known quantities of HCV were used to evaluate analytical sensitivity and precision.

RESULTS

The analytical sensitivity of the test was 25 IU of HCV per mL of pooled plasma; all HCV genotypes were detected with similar efficiency. The test did not react with other blood-borne viruses. The within-run and total coefficients of variation were 1.3-13.0 percent and 1.7-22.0 percent, respectively, with low copy samples producing the more variable results. The test performed well using plasma collected in either EDTA, ACD, or PPT Vacutainer tubes. Plasma samples containing elevated levels of hemoglobin, albumin, triglycerides, or bilirubin did not interfere with the test. The test detected HCV RNA 23 to 32 days prior to seroconversion for four of the five seroconversion panels tested.

CONCLUSION

The AmpliScreen HCV Test, Version 2.0 provides a reproducible and specific method for screening pooled blood units for HCV. Theoretically, this test has sufficient sensitivity to detect a single infected unit containing 2.4 x 10(3) IU of HCV per mL in a pool with 95 uninfected units and should reduce the window period by at least 20 to 30 days.

Comparison of 4 topical anesthetic agents for effect and corneal toxicity in rabbits

PURPOSE

To compare the onset time, duration of action, corneal toxicity, and corneal epithelial healing time of 4 topical anesthetic agents in rabbits.

SETTING

Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.

METHOD

Fifty-six rabbits were treated with 4 topical anesthetics (bupivacaine, lidocaine, procaine, and benzocaine) at different concentrations and different pH of solutions. Corneal sensation, corneal toxicity, and corneal epithelial healing time were measured.

RESULTS

The onset time of all 4 anesthetic agents was within 1 minute; however, bupivacaine and lidocaine produced significantly longer action than procaine or benzocaine (P < .05). Buffered bupivacaine and lidocaine had a significantly longer anesthetic effect than that of the nonbuffered solutions (P < .05). No significant effect on corneal epithelial healing time or corneal toxicity was observed.

CONCLUSION

Topical bupivacaine and lidocaine had a longer anesthetic effect, particularly in buffered solutions. No significant corneal toxicity was observed.

Stabilized plasmid-lipid particles for regional gene therapy: formulation and transfection properties

Previous work (Wheeler et al, Gene Therapy 1999; 6: 271-281) has shown that plasmid DNA can be entrapped in 'stabilized plasmid-lipid particles' (SPLP) containing the fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), low levels (5-10 mol%) of cationic lipid, and stabilized by a polyethyleneglycol (PEG) coating. The PEG moieties are attached to a ceramide anchor containing an arachidoyl acyl group (PEG-CerC20). These SPLP exhibit low transfection potencies in vitro, due in part to the long residence time of the PEG-CerC20 on the SPLP surface. In this work we employed SPLP stabilized by PEG attached to ceramide containing an octanoyl acyl group (PEG-CerC8), which is able to quickly exchange out of the SPLP, to develop systems that give rise to optimized in vitro and in vivo (regional) transfection. A particular objective was to achieve cationic lipid contents that give rise to maximum transfection levels. It is shown that by performing the dialysis procedure in the presence of increasing concentrations of citrate, SPLP containing up to 30 mol% of the cationic lipid dioleoydimethylammonium chloride (DODAC) could be generated. The SPLP produced could be isolated from empty vesicles by sucrose density gradient centrifugation, and exhibited a narrow size distribution (62 +/- 8 nm, as determined by freeze-fracture electron microscopy) and a high plasmid-to-lipid ratio of 65 microg/micromol (corresponding to one plasmid per particle) regardless of the DODAC content. It was found that isolated SPLP containing 20-24 mol% DODAC resulted in optimum transfection of COS-7 and HepG2 cells in vitro, with luciferase expression levels comparable to those achieved for plasmid DNA-cationic lipid complexes. In vivo studies employing an intraperitoneal B16 tumor model and intraperitoneal administration of SPLP also demonstrated maximum luciferase expression for DODAC contents of 20-24 mol% and significantly improved gene expression in tumor tissue as compared with complexes. We conclude that SPLP stabilized by PEG-CerC8 and containing 20-24 mol% cationic lipid are attractive alternatives to plasmid DNA-cationic lipid complexes for regional gene therapy applications.

A cost comparison of methohexital and propofol for ambulatory anesthesia

Methohexital is eliminated more rapidly than thiopental, and early recovery compares favorably with propofol. We designed this study to evaluate the recovery profile when methohexital was used as an alternative to propofol for the induction of anesthesia before either sevoflurane or desflurane in combination with nitrous oxide. One hundred twenty patients were assigned randomly to one of four anesthetic groups: (I) methohexital-desflurane, (II) methohexital-sevoflurane, (III) propofol-desflurane, or (IV) propofol-sevoflurane. Recovery times after the anesthetic drugs, as well as the perioperative side effect profiles, were similar in all four groups. A cost-minimization analysis revealed that methohexital was less costly for the induction of anesthesia. At the fresh gas flow rates used during this study, the costs of the volatile anesthetics for maintenance of anesthesia did not differ among the four groups. However, at low flow rates (< or = 1 L/min), the methohexital-desflurane group would have been the least expensive anesthetic technique. In conclusion, methohexital is a cost-effective alternative to propofol for the induction of anesthesia in the ambulatory setting. At low fresh gas flow rates, the methohexital-desflurane combination was the most cost-effective for the induction and maintenance of general anesthesia.

IMPLICATIONS

Using methohexital as an alternative to propofol for the induction of anesthesia for ambulatory surgery seems to reduce drug costs. When fresh gas flow rates < or = 1 L/min are used, the combination of methohexital for the induction and desflurane for maintenance may be the most cost-effective general anesthetic technique for ambulatory surgery.

Physicochemical and structural characterization of alkali soluble lignins from oil palm trunk and empty fruit-bunch fibers

Six alkali soluble lignin fractions were extracted from the cell wall materials of oil palm trunk and empty fruit-bunch (EFB) fibers with 5% NaOH, 10% NaOH, and 24% KOH/2% H(3)BO(3). All of the lignin fractions contained rather low amounts of associated neutral sugars (0.8-1.2%) and uronic acids (1.1-2.0%). The lignin fractions isolated with 5% NaOH from the lignified palm trunk and EFB fibers gave a relatively higher degree of polymerization as shown by weight-average molecular weights ranging between 2620 and 2840, whereas the lignin fractions isolated with 10% NaOH and 24% KOH/2% H(3)BO(3) from the partially delignified palm trunk and EFB fibers showed a relatively lower degree of polymerization, as shown by weight-average molecular weights ranging between 1750 and 1980. The results obtained by alkaline nitrobenzene oxidation showed that all of the lignin preparations contained a high proportion of noncondensed syringyl units with small amounts of noncondensed guaiacyl and fewer p-hydroxyphenyl units. The lignin fraction extracted with 5% NaOH from the lignified EFB fiber was mainly composed of beta-O-4 ether-linked units. Small amounts of 5-5', beta-5, and beta-beta' carbon-carbon linkages were also found to be present between the lignin structural units. Further studies showed that uronic, p-hydroxybenzoic, and ferulic acids in the cell walls of palm fibers were esterified to lignin.

Multi-agent reinforcement learning: weighting and partitioning

This article addresses weighting and partitioning, in complex reinforcement learning tasks, with the aim of facilitating learning. The article presents some ideas regarding weighting of multiple agents and extends them into partitioning an input/state space into multiple regions with differential weighting in these regions, to exploit differential characteristics of regions and differential characteristics of agents to reduce the learning complexity of agents (and their function approximators) and thus to facilitate the learning overall. It analyzes, in reinforcement learning tasks, different ways of partitioning a task and using agents selectively based on partitioning. Based on the analysis, some heuristic methods are described and experimentally tested. We find that some off-line heuristic methods perform the best, significantly better than single-agent models.

Cellular tropism and viral interleukin-6 expression distinguish human herpesvirus 8 involvement in Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease

Human herpesvirus 8 (HHV-8) infection has been implicated in the etiology of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD), three diseases that frequently develop in immunocompromised, human immunodeficiency virus-positive individuals. One hypothesis that would account for different pathological manifestations of infection by the same virus is that viral genes are differentially expressed in heterogeneous cell types. To test this hypothesis, we analyzed the localization and levels of expression of two viral genes expressed in latent and lytic infections and the viral homologue of interleukin-6 (vIL-6). We show that PEL parallels KS in the pattern of latent and lytic cycle viral gene expression but that the predominant infected cell type is a B cell. We also show that MCD differs from KS not only in the infected cell type (B-cell and T-cell lineage) but also in the pattern of viral gene expression. Only a few cells in the lesion are infected and all of these cells express lytic-cycle genes. Of possibly greater significance is the fact that in a comparison of KS, PEL, and MCD, we found dramatic differences in the levels of expression of vIL-6. Interleukin-6 is a B-cell growth and differentiation factor whose altered expression has been linked to plasma cell abnormalities, as well as myeloid and lymphoid malignancies. Our findings support the hypothesis that HHV-8 plays an important role in the pathogenesis of PEL and MCD, in which vIL-6 acts as an autocrine or paracrine factor in the lymphoproliferative processes common to both.

Effect of diclofenac sodium and dexamethasone on cultured human Tenon's capsule fibroblasts

BACKGROUND AND OBJECTIVE

To investigate the effect of diclofenac sodium and dexamethasone on cultured human Tenon's capsule fibroblasts.

MATERIALS AND METHODS

Two experiments were conducted. In the first experiment, fibroblasts were treated with either diclofenac sodium or dexamethasone at different concentrations, and the cell growth was quantified by using Coulter counter and hexosaminidase methods at 1, 3, 5, and 7 days after adding the drugs. In the second experiment, the cells were treated with each drug for 24 hours and then the cultures were switched to a drug-free medium. The cell growth was quantified at day 7 after removing the drugs from the medium.

RESULTS

In the first experiment, inhibition of fibroblast growth in a dose-dependent manner was observed from days 1 to 7 in the cultures treated with each drug. The inhibitory was more pronounced in the diclofenac treated cultures. The typical spindle-shaped fibroblasts treated with higher concentrations of the drugs became spherical cells. In the second experiment, inhibition was not observed when the cultures were switched to a drug-free medium. The spherical cells recovered to spindle-shaped cells and proliferated as normal cells.

CONCLUSION

Our results have shown that diclofenac sodium and dexamethasone can significantly inhibit human Tenon's capsule fibroblast growth in a cell culture model. The inhibitory effect was not observed when the cultures were switched after 24 hours to a drug-free culture medium.

Prolactin exerts hematopoietic growth-promoting effects in vivo and partially counteracts myelosuppression by azidothymidine

Prolactin (PRL) is a neuroendocrine hormone that influences immune and hematopoietic development. The mechanism of action of this hormone in vivo remains unclear; therefore, we assessed the effects of PRL on hematopoiesis in vivo and in vitro. Normal resting mice were treated with 0, 1, 10, or 100 microg of recombinant human prolactin (rhPRL) for 4 consecutive days and euthanized on the fifth day for analysis of myeloid and erythroid progenitors in the bone marrow and spleen. Both frequencies and absolute numbers of splenic colony-forming unit granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-e) were significantly increased in mice receiving rhPRL compared to the controls that had received saline only. Bone marrow cellularities were not significantly affected by any dose of rhPRL, but the absolute numbers and frequencies of bone marrow CFU-GM and BFU-e were augmented by rhPRL. These results suggest that rhPRL can promote hematopoiesis in vivo. Because rhPRL augments myeloid development in vivo, we examined the potential of the hormone to reverse the anemia and myelosuppression induced by azidothymidine (AZT). Mice were given rhPRL injections concurrent with 2.5 mg/mL AZT in drinking water. rhPRL partially restored hematocrits in the animals after 2 weeks of treatment and increased CFU-GM and BFU-e in both spleens and bone marrow. The experiments with AZT and rhPRL support the conclusion that the hormone increases myeloid and erythroid progenitor numbers in vivo, and they suggest that the hormone is clinically useful in reversing myelosuppression induced by AZT or other myeloablative therapies.

Kinetics of Kaposi's sarcoma-associated herpesvirus gene expression

Herpesvirus gene expression can be classified into four distinct kinetic stages: latent, immediate early, early, and late. Here we characterize the kinetic class of a group of 16 Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 genes in a cultured primary effusion cell line and examine the expression of a subset of these genes in KS biopsies. Expression of two latent genes, LANA and vFLIP, was constitutive and was not induced by chemicals that induce the lytic cycle in primary effusion lymphoma (PEL) cell lines. An immediate-early gene, Rta (open reading frame 50 [ORF50]), was induced within 4 h of the addition of n-butyrate, and its 3.6-kb mRNA was resistant to inhibition by cycloheximide. Early genes, including K3 and K5 that are homologues of the "immediate-early" gene of bovine herpesvirus 4, K8 that is a positional homologue of Epstein-Barr virus BZLF1, vMIP II, vIL-6, and polyadenylated nuclear (PAN) RNA, appeared 8 to 13 h after chemical induction. A second group of early genes that were slightly delayed in their appearance included viral DHFR, thymidylate synthase, vMIP I, G protein-coupled receptor, K12, vBcl2, and a lytic transcript that overlapped LANA. The transcript of sVCA (ORF65), a late gene whose expression was abolished by Phosphonoacetic acid, an inhibitor of KSHV DNA replication, did not appear until 30 h after induction. Single-cell assays indicated that the induction of lytic cycle transcripts resulted from the recruitment of additional cells into the lytic cycle. In situ hybridization of KS biopsies showed that about 3% of spindle-shaped tumor cells expressed Rta, ORF K8, vIL-6, vMIP I, vBcl-2, PAN RNA, and sVCA. Our study shows that several KSHV-encoded homologues of cellular cytokines, chemokines, and antiapoptotic factors are expressed during the viral lytic cycle in PEL cell lines and in KS biopsies. The lytic cycle of KSHV, probably under the initial control of the KSHV/Rta gene, may directly contribute to tumor pathogenesis.

Effects of temperature and photoperiod on thermogenesis in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus)

We examined the effects of temperature and photoperiod on metabolic thermogenesis and the thermogenic characteristics of brown adipose tissue in plateau pikas (Ochotona curzoniae) and root voles (Microtus oeconomus), the dominant species of small mammals in the alpine meadow ecosystems on the Qinghai-Tibetan Plateau. Pikas and voles were acclimated in the following groups: (1) Long day-warm temperature (16L:8D, 23 degrees C) (2) Long day-cold temperature (16L:8D, 5 degrees C), (3) short day-warm temperature (8L:16D, 23 degrees C), and (4) short day-cold temperature (8L:16D, 5 degrees C). Both temperature and photoperiod were important environmental cues for changes in thermogenesis for both species. Low temperature and short photoperiod induced increases in metabolic rate, nonshivering thermogenesis (NST), mitochondrial protein contents of brown adipose tissue, and cytochrome C oxidase activity of brown adipose tissue mitochondria in both species. Plateau pikas were more sensitive to cold (79% of the total NST response) than to short photoperiod (21%), while root voles were more sensitive to short photoperiod (60% of the total NST response) than to cold (40%), although cold clearly enhanced thermogenesis. Their thermogenic characteristics correlated with their preferred habitats: plateau pikas are found mainly in more exposed microhabitats in open sunny meadow, while root voles live in more sheltered microhabitats in relatively closed shrub. Our results also showed that temperature and photoperiod combined induce thermogenic adjustments in both species in seasonal acclimatization in their alpine meadow macrohabitat.

[Omega-mercaptohexanoic acid self-assemble-modified gold electrode and its catalytic property for redox reaction of chlorophylls]

Omega-mercaptohexanoic acid (6-MHA) self-assemble-modified gold electrode has been made by the authors. The SERS spectrum and the variations of double-layer capacitance (Cd) which occurred in the formation of 6-MHA self-assembled monolayers (SAM) on gold electrode surface were studied. The structure model of this SAM was deduced. The results show that 6-MHA can form stable SAM on gold electrode, and this 6-MHA SAM electrode has obvious catalysis for the redox reaction of chlorophylls.

[A rational selection of retroperitoneal lymphadenectomy for advanced epithelial ovarian cancer]

OBJECTIVE

To evaluate the rational application of retroperitoneal lymphadenectomy to advanced epithelial ovarian cancer.

METHODS

42 patients of advanced epithelial ovarian cancer were treated by retroperitoneal lymphadenectomy. Two groups were divided according to the residual disease post-operation. A: 26 patients with the residual disease < 2 cm; B: 16 patients > or = 2 cm. The regime of combined chemotherapy was the same in the two groups after operation. Clinical stage and pathologic grade showed no difference.

RESULTS

The 5-year survival rate was 53.8% (14/26) in A and 12.5% (2/16) in B. There was a significant difference between the two groups (P < 0.001).

CONCLUSIONS

The survival rate could be greatly improved for advanced epithelial ovarian cancer through retroperitoneal lymphadenectomy when the residual disease was smaller than 2 cm. This procedure would not be performed if the residual disease was larger than or equal to 2 cm.

Use of neuroendocrine hormones to promote reconstitution after bone marrow transplantation

A survey of the previous literature and the data shown here indicate that neuroendocrine hormones such as growth hormone and prolactin may be of potential clinical use after bone marrow transplantation (BMT) to promote hematopoietic and immune recovery. The amounts of hormones used in our model do not promote weight gain suggesting that their lymphohematopoietic actions were independent of their anabolic effects. While the hormones may not produce the same extent of immune/hematopoietic effects when compared to conventional hematopoietic and immune stimulating cytokines (i.e. IL-2 or G-CSF), their pleiotropic effects and limited toxicity after systemic administration makes them attractive to test in the post-BMT setting. However, more work needs to be performed to understand the mechanism(s) of their action, particularly with regard to T-cell function and development.

Evaluation of a commercial PCR kit for diagnosis of cytomegalovirus infection of the central nervous system

We evaluated the AMPLICOR cytomegalovirus (CMV) PCR kit for the diagnosis of neurologic CMV infections on 43 positive and 112 negative archived cerebrospinal fluid specimens originally tested by an in-house PCR method. The AMPLICOR kit showed sensitivity and specificity of 95 and 100%, respectively, versus the home-grown assay, indicating its utility in this clinical setting.

Ultrasensitive reverse transcription-PCR assay for quantitation of human immunodeficiency virus type 1 RNA in plasma

With the recent introduction of combination therapy, human immunodeficiency virus type 1 (HIV-1) RNA levels in plasma have been dramatically reduced, frequently to below the limit of quantitation (400 copies/ml of plasma) of the AMPLICOR HIV-1 MONITOR Test (Roche Diagnostic Systems). To achieve enhanced sensitivity of the AMPLICOR HIV-1 MONITOR Test, a modified specimen preparation procedure that allows input of RNA from 10-fold more plasma per amplification reaction was developed. This "ultrasensitive" method allows the accurate quantitation of plasma HIV-1 RNA levels as low as 50 copies/ml. A precision study yielded average within-run and between-run coefficients of variation (CV) of 24.8 and 9.6%, respectively. A multicenter reproducibility study demonstrated that the laboratory-to-laboratory reproducibility of this assay is good, with an average CV of 32%. The linear range of this test is between 50 and 50,000 copies/ml of plasma. RNA concentrations measured by the ultrasensitive and standard HIV-1 MONITOR tests exhibited good agreement within the shared linear range of the two methods. The two measurements were within a factor of 2 for 91% of the specimens tested, with the concentration measured by the ultrasensitive method being only slightly lower (median, 22% lower). Preliminary studies suggest that this assay will prove to be useful for predicting the stability of viral suppression in patients whose RNA levels drop below 400 copies/ml in response to highly active antiretroviral therapy.

Evaluation of the AMPLICOR cytomegalovirus test with specimens from human immunodeficiency virus-infected subjects

The AMPLICOR cytomegalovirus (CMV) test, a new qualitative assay for the detection of CMV DNA in plasma, was compared to conventional methods and quantitative PCR (Q-PCR) assays by using leukocytes and plasma from 179 blood samples from subjects with AIDS. For the diagnosis of CMV disease, cell-based assays such as a Q-PCR with polymorphonuclear leukocytes (Q-PCR-PMNL) and a pp65 antigenemia assay had the highest sensitivities but suffered from a lack of specificity. The best agreement between the results of the Q-PCR-PMNL assay and those of the AMPLICOR test was found when a threshold diagnostic value of 690 copies per 10(5) cells was selected for the Q-PCR-PMNL assay. In that context, the AMPLICOR CMV test had a sensitivity of 96.4% and a specificity of 95.3% when results were compared to results of the cell-based PCR assay. This threshold was close to the one described as associated with the best sensitivity and specificity for the diagnosis of CMV disease in a recently published study (4). Blood samples that tested positive by the Q-PCR-PMNL assay but negative by the AMPLICOR CMV test were associated with viral loads (mean, 785 copies, median, 96 copies per 10(5) leukocytes) lower than the viral loads of blood samples that tested positive by both assays (mean, 21,452 copies; median, 9,784 copies per 10(5) leukocytes) (P = 0.003). The AMPLICOR CMV test gave positive results at least 48 days before the development of symptomatic CMV disease in a longitudinal analysis of a limited subset of patients (n = 6) from whom sequential specimens were available for testing. In conclusion, the AMPLICOR CMV test is a very convenient assay combining rapidity, simplicity, and the possibility of batch testing. A positive result by this test seems particularly important since this implies, in most instances, the presence or the imminence of CMV disease, although a negative test result does not rule out disease.

Beta cyclodextrins enhance adenoviral-mediated gene delivery to the intestine

PURPOSE

In general, the intestinal epithelium is quite refractory to viral and non-viral methods of gene transfer. In this report, various cyclodextrin formulations were tested for their ability to enhance adenoviral transduction efficiency in two models of the intestinal epithelium: differentiated Caco-2 cells and rat jejunum.

METHODS

Transduction efficiency of replication-deficient adenovirus type 5 vectors encoded with either the E. coli beta-galactosidase or the jellyfish green fluorescent protein gene was assessed by X-gal staining or visualization of fluorescence 48 hours after infection. In vivo experiments were performed using an intestinal loop ligation technique.

RESULTS

Several formulations of neutral and positively charged beta cyclodextrins significantly enhanced adenoviral-mediated gene transfer in the selected models. The cyclodextrin formulations studied increased adenoviral transduction in the intestine by enhancing both viral binding and internalization. Viral binding was significantly increased on cell membranes treated with positively charged cyclodextrins, as seen with confocal microscopy and rhodamine-labeled virus. Permeability studies and TEER readings revealed that the most successful formulations gently disrupt cell membranes. This enhances internalization of viral particles and results in increased levels of gene expression.

CONCLUSIONS

These formulations can be of value in gene transfer to cells and tissues in which adenoviral infection is limited due to a lack of fiber and alpha(v) integrin receptors. They are simple to prepare and do not affect the ability of the virus to transduce target cells.

Expression of mucin-type glycoprotein K88 receptors strongly correlates with piglet susceptibility to K88(+) enterotoxigenic Escherichia coli, but adhesion of this bacterium to brush borders does not

Three antigenic variants of the K88 fimbrial adhesin exist in nature, K88ab, K88ac, and K88ad. Enterotoxigenic Escherichia coli (ETEC) strains that produce these fimbriae cause life-threatening diarrhea in some but not all young pigs. The susceptibility of pigs to these organisms has been correlated with the adherence of bacteria to isolated enterocyte brush borders. Whether that correlation holds for multiple K88 variants and over a broad genetic base of pigs is unknown and was the impetus for this study. We also desired to examine the correlation of the expression of a porcine intestinal brush border mucin-type glycoprotein (IMTGP) which binds K88ab and K88ac with the susceptibility of piglets to K88(+) ETEC. Of 31 neonatal gnotobiotic pigs inoculated with K88ab+ or K88ac+ ETEC, 13 developed severe diarrhea, became dehydrated, and died or became moribund. Another pig became severely lethargic but not dehydrated. In vitro brush border adherence analysis was not possible for 10 of the severely ill pigs due to colonization by challenge strains. However, of the 17 pigs that did not become severely ill, 8 (47%) had brush borders that supported the adherence of K88ab+ and K88ac+ bacteria in vitro, suggesting a poor correlation between in vitro brush border adherence and piglet susceptibility to K88(+) ETEC. By contrast, the expression of IMTGP was highly correlated with susceptibility to K88(+) ETEC. Of the 12 pigs that produced IMTGP, 11 developed severe diarrhea. The other pig that produced IMTGP became lethargic but not severely diarrheic. Only 2 of 18 pigs that did not produce IMTGP became severely diarrheic. Colonizing bacteria were observed in histologic sections of intestines from all pigs that expressed IMTGP except for the one that did not develop severe diarrhea. However, colonizing bacteria were observed in histologic sections from only one pig that did not produce IMTGP. The bacterial concentration in the jejuna and ilea of pigs expressing IMTGP was significantly greater (P < 0.005) than that in pigs not expressing IMTGP. These observations suggest the IMTGP is a biologically relevant receptor for K88ab+ and K88ac+ E. coli or a correlate for expression for such a receptor.

A viral gene that activates lytic cycle expression of Kaposi's sarcoma-associated herpesvirus

Herpesviruses exist in two states, latency and a lytic productive cycle. Here we identify an immediate-early gene encoded by Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpesvirus eight (HHV8) that activates lytic cycle gene expression from the latent viral genome. The gene is a homologue of Rta, a transcriptional activator encoded by Epstein-Barr virus (EBV). KSHV/Rta activated KSHV early lytic genes, including virus-encoded interleukin 6 and polyadenylated nuclear RNA, and a late gene, small viral capsid antigen. In cells dually infected with Epstein-Barr virus and KSHV, each Rta activated only autologous lytic cycle genes. Expression of viral cytokines under control of the KSHV/Rta gene is likely to contribute to the pathogenesis of KSHV-associated diseases.