Gastro-oesophageal reflux disease: Medical or surgical treatment? Report of an interactive workshop

Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.     

Induction of primary anti-viral cytotoxic T cells by in vitro stimulation with short synthetic peptide and interleukin-7.

The present study investigated whether a short synthetic peptide NPP, with a modified sequence (147-158 R156-) derived from influenza A virus nucleoprotein with high affinity for Kd major histocompatibility complex class I molecules, could induce primary influenza virus-specific cytotoxic T (Tc) cells in vitro. Naive BALB/c (H-2d) splenocytes did not respond to the stimulation with only NPP with the generation of effector Tc cells specific for influenza A virus-infected target cells in vitro. However, they were able to do so if cultured with NPP in the presence of IL-7. IL-7 activity in this system differed significantly from IL-2 activity in the specificity of the effect. The use of exogenous IL-2, instead of IL-7, with NPP resulted in the induction of lytic cells that lysed both influenza virus-infected and uninfected syngeneic target cells. These results suggest that IL-7 is a potent regulatory cytokine in the antigen-specific activation of resting naive Tc cell precursors and may provide the necessary conditions for the induction of human primary Tc cells in vitro.     

Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains

We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.      

High-performance liquid chromatographic determination of p-aminohippuric acid and iothalamate in human serum and urine: comparison of two sample preparation methods

A high-performance liquid chromatography method applied to determine p-aminohippuric acid (PAH) and iothalamate (IOT) in serum and urine samples of patients was evaluated according to recovery, reproducibility and linearity utilizing narrow-bore columns. The mobile phase consisted of 0.15 M sodium dihydrogenphosphate with 1.2 mM tetrabutylammonium sulphate, the pH was adjusted to pH 4.6, acetonitrile was added to a final ratio of 95:5 (v/v), the flow-rate was set at 0.3 ml/min. The separation was achieved on a ODS Hypersil column (200 x 2.1 mm I.D.). The UV detector was set at 254 nm. PAH and IOT are used for evaluation of kidney function [effective renal plasma flow (ERPF) and glomerular filtration rate (GFR)]). Under the described chromatographic conditions two sample preparation techniques, ultrafiltration and acetonitrile precipitation were compared. The results demonstrate the accuracy of both methods in evaluation of ERPF and GFR. Due to its cost-effectiveness we recommend the acetonitrile precipitation method in clinical routine.     

Japanese encephalitis virus glycoproteins

Mature Japanese encephalitis (JE) virus, or N-form virus, contained three structural proteins: V-1, V-2, and V-3. The large membrane protein V-3 was glycosylated, whereas both V-1 (the small membrane protein) and V-2 (the nucleocapsid protein) were not. Intracellular (I-form), immature virions from infected chick embryo cells did not contain V-1 but a larger protein NV-2, which was glycosylated. T-form virions, released by LLC-MK₂ cells incubated with tris(hydroxymethyl)amino-methane (Tris), also contained the glycoprotein NV-2 instead of the nonglycosylated and smaller V-1. We therefore concluded that JE contained two structural membrane glycoproteins, at least one of which is modified during morphogenesis. The NV-2 polypeptide was heterogeneous, and slight differences in electrophoretic mobility were detected among the NV-2 polypeptide peaks from glucosamine-labeled I-form and T-form virions, glucosamine-labeled cell extracts, and amino acid-labeled cell extracts. The significance of these differences is not clear, but they may indicate that NV-2 is composed of several proteins of similar molecular weight. By analyzing extracts of infected cells labeled with glucosamine or amino acids, we tentatively classified the intracellular polypeptide NV-3 as a virus-specified nonstructural glycoprotein; this polypeptide may be a proteolytic fragment of V-3. The virus-specified polypeptides NV-5, NV-4, and NV-1 were classified as nonglycosylated, nonstructural proteins.     

Detection of lignin biopolymer- and vitamin E-stimulated reduction of DNA strand breaks in H2O2- and MNNG-treated mammalian cells by the comet assay

In this study the possible protective effects of water-soluble sulfur-free lignin biopolymer and vitamin E (alpha-tocopherol) on DNA in human VH10 cells and hamster V79 cells exposed to H2O2 and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated. The level of DNA damage (DNA strand breaks) was measured using single-cell gel electrophoresis, i.e., comet assay. Lignin biopolymer and vitamin E exhibited a protective effect against the overall DNA damage induced after H2O2 treatment. If H2O2-treated human cells were incubated for 90 minutes to ligate frank breaks of DNA, two lesion-specific enzymes, endonuclease III and formamidopyrimidine DNA glycosylase (FPG), significantly increased the level of DNA strand breaks originating from oxidized pyrimidines and purines. Preincubation of cells with lignin or vitamin E reduced mainly the level of oxidized pyrimidines. Reduction of oxidized purines was less evident. In addition, lignin biopolymer exhibited a protective effect against MNNG-induced DNA damage, whereas vitamin E exhibited a protective effect only against H2O2-induced DNA damage. These findings suggest that the antioxidant nature of lignin biopolymer enables a reduction of the level of frank breaks and of oxidized DNA bases in H2O2-treated cells, and its adsorptive capacity enables binding of nitroso compounds and reduction of alkylation in MNNG-treated cells.     

Lamina propria of sex cords in human fetal testis: an immunohistological and stereological study

Testicular peritubular cells are located in the lamina propria of seminiferous tubules. These cells, significantly contributing to the basal membrane of seminiferous epithelium, have been studied in a number of species. However, there is a lack of data on the development of the lamina propria in the human testis. The aim of our survey was to investigate the characteristics of the lamina propria and, in particular, peritubular cells in the fetal human testes by immunohistological and stereological methods. Therefore, testes (14–39 weeks of gestation, n=45) were dissected and fixed in a 4% buffered paraformaldehyde solution. Several pieces of each testis were embedded in paraffin and processed for immunohistochemical and stereological analysis. All investigated testes have shown sex cords in the process of development and differentiation. Morphologically, peritubular cells in the lamina propria can be divided into two types: fibroblast-like (FL) and myoid-like (ML) type (cells which much resemble mature myoid cells). By immunohistochemistry, both FL and ML cells are found to be strongly positive for the intermediate filament desmin, but negative for -smooth actin. While FL cells intensively express Ki-67 demonstrating proliferative activity, ML cells are found to be negative. The basement membrane of sex cords as well as the blood vessels of the interstitium show strong positivity to collagen IV and laminin. Concerning the correlation between the appearance of the investigated antigens with the gestational age, all antigens have been expressed (in the manner described above) already in the 14th week of gestation. The stereological analysis of the number (Nv) and volume (Vv) of peritubular cells indicates a pulsatile development of these cells in the lamina propria of the human fetal testis. While the stereological variables determined for FL cells show a gradual decrease, the same variables determined for ML cells demonstrate a successive increase. It appears that the lamina propria of the fetal human testes shares many of the properties previously discovered in rodents.     

Bacterial and mammalian DNA alkyltransferases sensitize Escherichia coli to the lethal and mutagenic effects of dibromoalkanes

Here we confirm and extend our previous studies demonstrating that the mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is markedly enhanced (not prevented) in bacteria expressing the O6- alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli ogt gene. We demonstrate that, in close parallel with mutagenesis, the Ogt ATase sensitizes the bacteria to the lethal effects of these carcinogens, suggesting that one or more of the potentially mutagenic lesions induced by DBE and DBM in the presence of Ogt has additional lethal capacity. We further demonstrate that the sensitization to both lethality and mutagenesis by DBE and DBM is a property shared by other DNA alkyltransferases. This objective was accomplished by quantifying the induction of mutations and lethal events in ogt- ada- E. coli expressing an exogenous bacterial or mammalian ATase from a multicopy plasmid. Mammalian recombinant ATases enhanced the lethal and mutagenic actions of DBE and suppressed the lack of sensitivity of the vector- transformed bacteria to DBM. In most cases the order of effectiveness of the ATases ranked: murine > human > Ogt > rat. Further comparisons included the full-length Ada ATase from E. coli and a truncated Ada version (T-ada) that retains the O6-methylguanine binding domain of the protein. The full-length Ada ATase was effective in enhancing the lethality but not the mutagenicity induced by DBE and DBM. The T-ada ATase provided less sensitization than Ada to lethality by DBE, but of the three bacterial ATases T-ada yielded the highest sensitization to mutagenesis by this compound. T-ada and Ada ATases were in general less effective than the mammalian versions, with the exception of the rat recombinant ATase. The effectiveness of the different mammalian and bacterial ATases in promoting the deleterious actions of dibromoalkanes was compared with the effectiveness of these proteins in suppressing the lethal and mutagenic effects induced by N-nitroso-N-methylurea. The ability to sensitize E. coli to the lethal and mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase, since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt- ada- cells showed no effect, in spite of the reported potential of bioactive dihaloethane- derived species to alkylate Trx.