[The Raman spectra study on crystal-octadecyl hydrogen maleate (OHM)]

Raman spectra of crystal-octadecyl hydrogen maleate (OHM), whose geometric disposition of the experiment has y (zx) y y(zz)y, and y(xz)y, y(xx)y respectively, have been recorded and analyzed with the purpose of understanding the structure of OHM crystal. It shows that some of the Raman-active modes of alkyl chain appear polarization. The analysis for crystal structure indicates that the molecular of OHM arrange in layers along [100] and [001] by the mode of dimers, and the molecular layers of chain pile up along [010]. The other groups of OHM corresponding Raman vibration peaks have been analysed as well.

[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.