Functional analysis of the cag pathogenicity island in Helicobacter pylori isolates from patients with gastritis, peptic ulcer, and gastric cancer

Helicobacter pylori is the causative agent of a variety of gastric diseases, but the clinical relevance of bacterial virulence factors is still controversial. Virulent strains carrying the cag pathogenicity island (cagPAI) are thought to be key players in disease development. Here, we have compared cagPAI-dependent in vitro responses in H. pylori isolates obtained from 75 patients with gastritis, peptic ulcer, and gastric cancer (n = 25 in each group). AGS gastric epithelial cells were infected with each strain and assayed for (i) CagA expression, (ii) translocation and tyrosine phosphorylation of CagA, (iii) c-Src inactivation, (iv) cortactin dephosphorylation, (v) induction of actin cytoskeletal rearrangements associated with cell elongation, (vi) induction of cellular motility, and (vii) secretion of interleukin-8. Interestingly, we found high but similar prevalences of all of these cagPAI-dependent host cell responses (ranging from 56 to 80%) among the various groups of patients. This study revealed CagA proteins with unique features, CagA subspecies of various sizes, and new functional properties for the phenotypic outcomes. We further showed that induction of AGS cell motility and elongation are two independent processes. Our data corroborate epidemiological studies, which indicate a significant association of cagPAI presence and functionality with histopathological findings in gastritis, peptic ulcer, and gastric cancer patients, thus emphasizing the importance of the cagPAI for the pathogenicity of H. pylori. Nevertheless, we found no significant association of the specific H. pylori-induced responses with any particular patient group. This may indicate that the determination of disease development is highly complex and involves multiple bacterial and/or host factors.     

Über die sogenannten Myxome des Herzens

Zusammenfassung Die 15jährige Patientin litt wiederholt an Angina, die wohl über einer latenten Sepsis zu einer Endokardveränderung führte. Diese bedingte einen Thrombus des linken Vorhofes in der Gegend der Fossa ovalis. Aus der Zeit rühren embolische Narben der Milz und der linken Niere her. Unter eintretender Organisation des Thrombus wurde er durch den Blutstrom zu einem polypenförmigen Gebilde abgeglättet und ausgezogen. Er reichte nun durch das Ostium venosum sin. hindurch in die linke Herzkammer hinein und täuschte klinisch eine Insuffizienz der Klappe mit Stenose des Ostiums vor. Der organisierte Thrombus entartete in seinem größten Teile schleimig, während der neu angebildete Teil an der Basis auch jetzt noch wie ein typischer organisierter Thrombus aussah. Mikroskopisch konnte ich alle Bestandteile nachweisen, die die Autoren in den Myxomen beschrieben. Auch fand ich entzündliche Elemente, ebenso hyalines Fibrin, besonders in dem jüngeren, basalen Teile des Gebildes. Aus alledem komme ich zur Diagnose Thrombus myxomatodes und meine, daß auch alle die bisher beschriebenen primären Tumoren des endokards, außer den bösartigen Gewächsen, organisierte Thromben darstellen.Mit 5 Textabbildungen.     

Use of soluble recombinant TNF receptor to improve detection of TNF secretion in cultures of tumor infiltrating lymphocytes.

The accurate quantitation of picogram amounts of TNF is possible by ELISA and is useful in many areas of biomedical research, including studies of TNF release in vitro by stimulated lymphocytes and macrophages, and of serum levels in patients with cancer and sepsis. However, we show in this report that the detection of recombinant TNF standards by ELISA falls over time with incubation at 37 degrees C, and is further decreased when incubated with tumor infiltrating lymphocytes (TIL), making accurate quantitation difficult. We demonstrate that the soluble dimeric form of the TNF receptor can prevent this decrease, both in the presence and absence of TIL. In contrast, the soluble monomeric TNF receptor was much less effective in preventing this decrease. In addition, the dimeric but not the monomeric TNF receptor was found to inhibit bioactivity of TNF as measured by L929 cytotoxicity. The dimeric TNF receptor does not interfere with the detection of recombinant TNF standards by ELISA, and entirely stabilizes TNF levels incubated over 48 h at 37 degrees C in the presence and absence of TIL. This protection is specific, and the TNF receptor does not stabilize interferon-gamma. The dimeric form of the soluble TNF receptor has proven useful in detecting TNF released by TIL transduced with the TNF cDNA that are currently being used in studies of the gene therapy of cancer with TIL. The dimeric TNF receptor may also prove useful in the accurate quantitation of TNF released by stimulated lymphocytes and macrophages in vitro, and in the quantitation of serum TNF levels in patients.     

Bestimmung der Bindung von Trijodthyronin an Serumproteine mittels Dextran-Gel-Filtration

Zusammenfassung 1. Es wird eine Methode zur gleichzeitigen Bestimmung des sog. freien und des proteingebundenen Anteils von in vitro zugesetztem L-Trijodthyronin-¹³¹Jod im Serum mittels Dextran-Gel-Filtration angegeben. In der beschriebenen Form ist diese Technik für die routinemäßige Anwendung in der Klinik zur Bestimmung der Bindungs- und Transportverhältnisse von Trijodthyronin geeignet.2. In sog. Verdrängungsversuchen wurde nichtmarkiertes Trijodthyronin dem Inkubationsgemisch von Serum und L-Trijodthyronin-¹³¹Jod zugesetzt. Die zugesetzten Trijodthyroninmengen erschöpfen die Gesamtbindungskapazität der Serumproteine in dem gewählten Konzentrationsbereich keineswegs. Im Gegensatz zum Verhalten der prozentualen Anteile des sog. freien und des proteingebundenen Trijodthyronins steigt die absolute Menge des proteingebundenen Trijodthyronins dabei steil an. Man findet eine Kurve, die nicht einer einfachen Sättigunskurve entspricht, sondern eine Resultante aus Sättigungskurven verschiedener Trijodthyronin-bindender Proteine und Verdrängungskurven kompetitiv gebundener Substanzen (z.B. Thyroxin) darstellt.3. Dextran-Gel wirkt nicht als einfaches Molekülsieb für Trijodthyronin. Es greift vielmehr durch Adsorptionsvorgänge kompetitiv in die Serumproteinbindungsverhältnisse des Trijodthyronins ein. Die physiologische Bedeutung des sog. freien Anteils an Trijodthyronin wird diskutiert.4. Die Methode zur Bestimmung des proteingebundenen Jods (PB¹²⁷I) mittels alkalischer offener Veraschung (Barker) wurde technisch vereinfacht und bezüglich ihrer Reproduzierbarkeit untersucht. Die¹³¹Jodausbeute aus zugesetztem L-Thyroxin-¹³¹Jod lag bei diesem Verfahren bei ca. 80%.

---

Summary 1. A method allowing the simultaneous determination in serum of the socalled free and the protein bound part of 1-triiodothyronine-¹³¹I added in vitro, using dextran gel filtration, is presented. Assessment of serum protein binding and transport of triiodothyronine can be conveniently performed for clinical purposes by this procedure.2. In socalled discharge experiments non-labelled triiodothyronine is added to incubation mixtures of serum and l-triiodothyronine-¹³¹I. The amount of added triiodothyronine did not exhaust the total binding capacity of serum proteins for triiodothyronine. In contrast to the behaviour of the percentages of socalled free and protein bound triiodothyronine the absolute amount of protein bound triiodothyronine was rising linearly with rising concentrations of triiodothyronine added. The curve obtained was interpreted as resulting from saturation curves of different triiodothyronine binding proteins and discharge curves of competitively bound substances, e.g. thyroxine.3. Dextran gel is not acting merely as molecular sieve for triiodothyronine, but rather competing actively with serum proteins for triiodothyronine, adsorbing the latter. The physiological rôle of the socalled free triiodothyronine is discussed.4. With addition of l-thyroxine-¹³¹I 80% of¹³¹iodine was recovered, when the method ofBarker for determination of serum protein bound¹²⁷iodine (open alkaline ashing) was used.

---

---

Mit Unterstützung der Deutschen Forschungsgemeinschaft.

---

Herrn Prof. Dr. Dr. h. c.Carl Krauspe in Verehrung zum 70. Geburtstag gewidmet.     

Performance characteristics of four immunoassays for antiepileptic drugs on the IMMULITE 2000 automated analyzer

Carbamazepine, phenobarbital, phenytoin, and valproic acid are commonly used antiepileptic drugs that show complicated pharmacokinetic behavior Nonisotopic immunoassays are used routinely to monitor these drugs, and assay specificity is important to obtain accurate results. By using samples from subjects receiving each of these antiepileptic medications, competitive immunoassays for them were evaluated on an IMMULITE 2000 automated chemiluminescent analyzer (Diagnostic Products, Los Angeles, CA). Phenytoin assays were evaluated using an additional set of samples from patients with abnormal renal function. All 4 methods were linear, had imprecision of less than 10%, and compared well with other commercial immunoassays. A positive bias was observed for phenytoin measured in samples from uremic patients compared with a high-performance liquid chromatography reference method. The molar cross-reactivity of carbamazepine-10,11-epoxide was 12% in the carbamazepine assay. Phenytoin metabolites and fosphenytoin had substantial cross-reactivity in the phenytoin assay. All antiepileptic drug assays performed well and are suitable for use in monitoring patients receiving antiepileptic drug therapy. One possible exception is the phenytoin assay with samples from patients with renal insufficiency.     

Comparison of lymphocyte populations bearing surface immunoglobulins in avian bone marrow, bursa, spleen and thymus.

Rabbit anti-chicken gamma-globulin was labeled with 125I and then incubated with cells from the bursa, thymus, spleen, and bone marrow of 4- and 8-week old birds. The same procedure was carried out on 11-week-old agammaglobulinemic chickens. Autoradiography revealed that the majority of large, medium, and small bursal lymphocytes bind the antibodies while labeled lymphocytes of each type in the spleen and thymus never exceeded 11 or 4 percent, respectively. Labeled medium and small lymphocytes in the bone marrow increased from 4.2 and 1.7%, respectively, at 4 weeks of age, to 9.5 and 8.8%, respectively, at 8 weeks of age. Labeled lymphocytes of all sizes were completely absent in all tissues of agammaglobulinemic chicks, including the marrow. Therefore, the increase in frequency of labeled lymphocytes in the bone marrow with age may be a result of recruitment of cells from the bursa of Fabricius. The majority of lymphocytes in the bone marrow do not label. Therefore, lymphocytes from the bone marrow may be T cells, subsets of B cells, or neither T or B cells.     

Impaired sodium excretion, decreased glomerular filtration rate and elevated blood pressure in endothelin receptor type B deficient rats

The renal endothelin (ET) system, particularly the ET type B receptor, has been implicated in the regulation of sodium excretion and glomerular filtration rate (GFR). We analyzed kidney morphology and function in a rat strain characterized by complete absence of a functional ETB receptor. Due to Hirschsprung's disease limiting lifetime in these rats, studies were performed in 23-day-old rats. Kidney size and morphology (glomerular and interstitial matrix content, glomerular size and cell density and intrarenal vascular morphology) were normal in ETB-deficient rats. There were also no evidence of altered kidney cell cycle regulation in these rats. GFR was significantly lower, by 72% (P<0.001), in homozygous ETB-deficient rats than in wild-type rats. Fractional sodium excretion was likewise markedly reduced by 84% in homozygous ETB-deficient rats (P<0.001 versus wild-type rats). Treatment with the specific epithelial sodium channel blocker amiloride led to a much higher increase in fractional sodium excretion in ETB-deficient rats (934.2+/-73% in ETB-deficient rats versus 297+/-20% in wild-type rats, expressed as percentage of corresponding placebo treated control; P<0.001). Mean arterial blood pressure was elevated by 7.9 mmHg in homozygous ETB-deficient rats (P<0.05 versus wild-type rats). Our study demonstrates that ETB-deficiency causes early onset kidney dysfunction characterized by a markedly reduced sodium excretion, decreased GFR, and slightly elevated blood pressure. The complete absence of the ETB receptor causes in the kidney--in contrast to the colon--a functional rather than a developmental, neural crest cell dependent disease, since kidney morphology was normal in ETB-deficient rats. The much higher increase in the fractional sodium excretion in ETB-deficient rats after pharmacological blockade of the epithelial sodium channel indicates that the decreased fractional sodium excretion in ETB-deficient rats is most probably due to a lack of the inhibitory property of the ETB receptor on the epithelial sodium channel activity.     

Efficient correction for CT image artifacts caused by objects extending outside the scan field of view

The purpose of this paper is to develop a method of eliminating CT image artifacts generated by objects extending outside the scan field of view, such as obese or inadequately positioned patients. CT projection data are measured only within the scan field of view and thus are abruptly discontinuous at the projection boundaries if the scanned object extends outside the scan field of view. This data discontinuity causes an artifact that consists of a bright peripheral band that obscures objects near the boundary of the scan field of view. An adaptive mathematical extrapolation scheme with low computational expense was applied to reduce the data discontinuity prior to convolution in a filtered backprojection reconstruction. Despite extended projection length, the convolution length was not increased and thus the reconstruction time was not affected. Raw projection data from ten patients whose bodies extended beyond the scan field of view were reconstructed using a conventional method and our extended reconstruction method. Limitations of the algorithm are investigated and extensions for further improvement are discussed. The images reconstructed by conventional filtered backprojection demonstrated peripheral bright-band artifacts near the boundary of the scan field of view. Images reconstructed with our technique were free of such artifacts and clearly showed the anatomy at the periphery of the scan field of view with correct attenuation values. We conclude that bright-band artifacts generated by obese patients whose bodies extend beyond the scan field of view were eliminated with our reconstruction method, which reduces boundary data discontinuity. The algorithm can be generalized to objects with inhomogeneous peripheral density and to true "Region of Interest Reconstruction" from truncated projections.