Sensitivity of transformed fibroblasts for intercellular induction of apoptosis is determined by their transformed phenotype

Intercellular induction of apoptosis defines a potential control mechanism of oncogenesis. It is based on induction of apoptosis in transformed fibroblasts by neighboring nontransformed fibroblasts. Transforming growth factor type beta (TGF-beta) represents the initial triggering molecule to induce nontransformed cells to release apoptosis-inducing factors. To test whether sensitivity for intercellular induction of apoptosis is directly dependent on the transformed phenotype, v-src-transformed rat fibroblasts and emerging revertants were tested for their sensitivity. All transformed cell clones were sensitive, whereas all revertant clones had lost their sensitivity in parallel with the loss of the transformed phenotype. In addition, revertants had regained the potential to induce apoptosis in transformed cells. Sensitivity to intercellular induction of apoptosis is therefore directly dependent on the transformed phenotype, whereas the ability to induce apoptosis is a specific feature of nontransformed fibroblasts.

Characterization of [35S]-ATP alpha S and [3H]-alpha, beta-MeATP binding sites in rat brain cortical synaptosomes: regulation of ligand binding by divalent cations

1. We made a comparative analysis of the binding characteristics of the radioligands [35S]-ATP alpha S and [3H]-alpha, beta-MeATP in order to test whether these ligands can be used to analyse P2-purinoceptors in synaptosomal membranes from rat brain cortex. 2. Synaptosomes possess sites with high affinity for [35S]-ATP alpha S (Kd = 22.2 +/- 9.1 nM, Bmax = 14.8 pmol mg-1 protein). The rank order of the competition potency of the different compounds (ATP alpha S, ATP, ATP gamma S > ADP beta S, 2-MeSATP > deoxyATP, ADP > > UTP, alpha, beta-MeATP, AMP, Reactive Blue-2, suramin, isoPPADS) is consistent with pharmacological properties of P2Y-purinoceptors. 3. Under identical conditions [35S]-ATP alpha S and [3H]-alpha, beta-MeATP bind to different binding sites at synaptosomal membranes from rat brain cortex. The affinity of the [3H]-alpha, beta-MeATP binding sites (Kd = 13.7 +/- 1.8 nM, Bmax = 6.34 +/- 0.28 pmol mg-1 protein) was 38 fold higher than the potency of alpha, beta-MeATP to displace [35S]-ATP alpha S binding (Ki = 0.52 microM). ATP and ADP beta S competed at both binding sites with different affinities, 60 fold and 175 fold, respectively. The other agonists tested (2-MeSATP, UTP, GTP) did not affect specific [35H]-alpha, beta-MeATP binding at concentrations up to 100 microM. The antagonists (suramin, isoPPADS, Evan's Blue) showed completely different affinities for both binding sites. 4. Binding of [35S]-ATP alpha S on synaptosomes was regulated by GTP, which is indicative for G-protein coupled receptors. The Kd value for the high affinity binding site was reduced in the presence of GTP about 5 fold (from 1.8 nM to 8.6 nM). In the presence of Mg2+ the affinity was increased (Kd 1.8 nM versus 22 nM in the absence of Mg2+). 5. The binding of both radioligands was regulated in an opposite manner by physiological concentrations of Ca2+ and Mg2+. Binding of [3H]-alpha, beta-MeATP to synaptosomal membranes was increased 3 fold by raising the Ca2+ concentration from 10 microM to 1 mM, whereas the addition of Mg2+ in the same concentration range resulted in an 80% reduction of the binding. In contrast, [35S]-ATP alpha S binding was not influenced at the same range of Ca2+ or Mg2+ concentrations (10 microM to 1 mM). The addition of Mg2+ (5 mM) increased the affinity of [35S]-ATP alpha S for the high affinity site 10 fold. 6. Diadenosine polyphosphates had a bimodal effect on [35S]-ATP alpha S binding to synaptosomal membranes. AP5A and Ap6A enhanced binding of [35S]-ATP alpha S 1.6 fold in a concentration range between 0.1 and 50 microM. Ap3A was a weak inhibitor with a Ki value of 7.2 microM. Ap4A, AP5A and Ap6A inhibited with Ki values > 100 microM. These data support the concept that diadenosine polyphosphates do not directly interact with ATP alpha S binding sites. 7. In conclusion, on the basis of present knowledge of the interaction of P2-purinoceptor active compounds with P2x- and/or P2Y-purinoceptors, our data strongly suggest that [35S]-ATP alpha S is a useful tool to study P2Y-purinoceptors. Thus, the [35S]-ATP alpha S binding site might to a large extent represent P2Y-purinoceptors in synaptosomes from rat brain cortex. The nucleotide binding is regulated by G proteins, indicated by the effects of GTP/Mg2+ on binding.

[Effect of endoscopic surgery techniques in children on ventilation]

The purpose of our study was to show the effects of laparoscopic procedures on the ventilation of children. We measured an increase of ventilation pressures (Pmax, Ppfat and Pmean) of 28, 35 and 48% respectively. petCO2 rose from 35 to 41 +/- 2 mmHg. There was no loss of body temperature in any child. Laparoscopic procedures as seen here for appendectomy or diagnostic exploration in children of 13.5 kg body weight or more caused no problems that were clinically evident. The increase of ventilation pressure could be attenuated by choosing the parameters of ventilation (e.g. flow, I:E ratio) in such a way that Pmax does not exceed 20 mbar. Alternatively, pressure-controlled ventilation may be used, adjusting petCO2 by ventilation frequency. In any case there must be a strict control of all possible side effects of laparoscopy, such as cutaneous emphysema or pneumothorax.

Reactive oxygen species as mediators of the transformed phenotype

Reactive oxygen species (ROS) are known to be involved in different pro- and anticarcinogenic mechanisms. However, their influence on the maintenance of the transformed phenotype has not been studied so far. Here we show that the anchorage-independent growth of transformed murine fibroblasts is inhibited by antioxidants and radical scavengers in a concentration-dependent and reversible manner. These agents also reduce TGF-beta-dependent stimulation of colony formation in soft agar, pointing to their specific interference with TGF-beta-triggered signal chains involved in the maintenance of the transformed state.

Anal endosonography and manometry: comparison in patients with defecation problems

PURPOSE

Correlations between anal sphincter function as assessed by anorectal manometry and anal sphincter anatomy measured by endoluminal ultrasound have been reported in the literature both for patients and for healthy individuals but have not been confirmed by other authors.

METHODS

For a larger series of patients (152 consecutive patients, mean age 54.1 +/- 15.5 years; female:male ratio, 111:41) with anorectal dysfunctions such as incontinence (n = 92), constipation (n = 37), and other symptoms (n = 23), diagnostic work-up included conventional multilumen anorectal manometry to evaluate internal sphincter pressure at rest, maximum external sphincter squeeze pressure during contraction, and endoanal sonography to determine anal sphincter integrity and to measure dorsal, left lateral, and right lateral diameter of the internal anal sphincter (IAS) and external anal sphincter (EAS) muscles.

RESULTS

Maximum squeeze pressure was significantly correlated to muscle thickness of the EAS (P = 0.001). No association was found between resting pressure and IAS diameter. Women had significantly lower resting and squeeze pressures than men (P = 0.008 and P = 0.003, respectively), but age-related changes of function were only found for resting pressure. Endosonographic values of IAS and EAS did not differ between genders but were significantly correlated with age (P = 0.008 and P = 0.02, respectively). Because all correlations were rather weak, they only can explain a small portion of data variance.

CONCLUSION

Anal manometry and anal ultrasound, therefore, are of complementary value and are both indicated in adequate clinical problems.

Growth-inhibitory activity and downregulation of the class II tumor-suppressor gene H-rev107 in tumor cell lines and experimental tumors

The H-rev107 gene is a new class II tumor suppressor, as defined by its reversible downregulation and growth-inhibiting capacity in HRAS transformed cell lines. Overexpression of the H-rev107 cDNA in HRAS-transformed ANR4 hepatoma cells or in FE-8 fibroblasts resulted in 75% reduction of colony formation. Cell populations of H-rev107 transfectants showed an attenuated tumor formation in nude mice. Cells explanted from tumors or maintained in cell culture for an extended period of time no longer exhibited detectable levels of the H-rev107 protein, suggesting strong selection against H-rev107 expression in vitro and in vivo. Expression of the truncated form of H-rev107 lacking the COOH-terminal membrane associated domain of 25 amino acids, had a weaker inhibitory effect on proliferation in vitro and was unable to attenuate tumor growth in nude mice. The H-rev107 mRNA is expressed in most adult rat tissues, and immunohistochemical analysis showed expression of the protein in differentiated epithelial cells of stomach, of colon and small intestine, in kidney, bladder, esophagus, and in tracheal and bronchial epithelium. H-rev107 gene transcription is downregulated in rat cell lines derived from liver, kidney, and pancreatic tumors and also in experimental mammary tumors expressing a RAS transgene. In colon carcinoma cell lines only minute amounts of protein were detectable. Thus, downregulation of H-rev107 expression may occur at the level of mRNA or protein.

How reproducible are measures of the anal sphincter muscle diameter by endoanal ultrasound?

Anal endosonography is an imaging technique for the anal sphincter system and offers analysis of its muscular integrity. It is generally assumed that measurement of the thickness of muscle layers is provided by sonography; however, reproducibility of such measurements have not yet been investigated.

METHODS

Study 1: In 10 healthy volunteers, endoanal ultrasound was performed independently by two experienced investigators with two different ultrasound machines, and thickness of the muscle layers of the internal and external anal sphincter was assessed in the position of the intermediate dorsal anal canal in a randomized cross-over fashion. Study 2: In a study of similar design, sonography was performed in nine healthy volunteers by two investigators independently using a single ultrasound machine in three standardized positions (proximal/intermediate/distal anal canal) and the sphincter layers assessed in the left, right, and dorsal segment.

RESULTS

Study 1: Both the same investigator with different ultrasound scanners and different investigators with the same machine failed to obtain reproducible results with respect to internal and external anal sphincter muscle layer diameter (four bivariate correlations, all with p > 0.05). Study 2: Standardization of the probe position did not improve the agreement (2 x 9 bivariate correlations, all but two p > 0.05).

CONCLUSION

At present, therefore, endoanal ultrasound does not provide reliable morphometric data on anal sphincter muscle diameter. This could explain previously conflicting observations of associations between anal sphincter morphometry and function.

[Cementless fixation of the endoprosthesis using trabecular, 3-dimensional interconnected surface structures]

While the principle of enlarging the surface area has been recognized and used in different ways for some time, there is often no schematic, detailed description or fundamental research. Taking a surface structure consisting of trabecular three-dimensional connecting elements, essential parameters are shown, making it clear that the flexible dynamic reaction of the effective "anchoring space" with a suitable specified shape (construction height, alignment, network) can be reproducibly shaped and used. This has led to a hip endoprosthesis with a graduated surface structure. The construction height of the trabecular structure varies, decreasing from proximal to distal.

[Psychosocial factors in Crohn disease--an overview]

In more than 50 years of psychosomatic research on Crohn's disease, several research hypotheses have been generated, which are critically reviewed here: A disease-specific personality could never be identified, and an important role of psychiatric and psychopathologic personality traits in disease onset was never substantiated. Moreover, most abnormalities found in psychological tests have to be regarded as secondary to chronic illness. Effects of psychologic and social stress on symptoms have not been validated, but it may be that Crohn's patients may have developed less coping abilities with daily hassles. Psychotherapy may improve this, but does not affect the clinical course of the disease.

Contractile response of the isolated trabecular meshwork and ciliary muscle to cholinergic and adrenergic agents

To characterize the contractile properties of isolated trabecular meshwork strips, we measured the effect of various cholinergic and adrenergic substances on the contractility of trabecular meshwork (TM) strips in comparison with the effects on ciliary muscle (CM) strips. Using an electromagnetic force length transducer we performed measurements of isometric tension on isolated bovine TM and CM strips. Isolated strips were contracted by cholinergic agonists, the relative potency being carbachol > pilocarpine > acetylcholine. The half-maximal effective concentration was 2 x 10(-7) mol l(-1) for carbachol and 2 x 10(-6) mol l(-1) for pilocarpine. To characterize muscarinic receptors, we tested selective antagonists for M1 (pirenzepine) and M3 (4-DAMP). Pharmacologically, the functional muscarinic receptors are of the M3 subtype in TM as well as CM. The M1 subtype seems to be less important. The alpha 1-agonist phenylephrine was more effective in inducing contractions in TM than in CM. The alpha 2-agonist brimonidine induced contractions only in TM. In precontracted tissues the beta-agonist isoproterenol induced a relaxation in both tissues. This relaxation could be inhibited by metipranolol. Epinephrine (or dipivefrin) induced small contractions in TM and CM, which became more prominent, especially in TM, when the beta-adrenoreceptors were inhibited by metipranolol. The data indicate the presence of functional muscarinic, alpha-adrenergic, and beta-adrenergic receptors in bovine TM and CM. The contractile properties of TM and CM are differently modulated by the various drugs. Cholinergic and alpha-adrenergic agonists induced contraction, whereas beta-agonists induced relaxation.

Deficient signaling in mice devoid of double-stranded RNA-dependent protein kinase

Double-stranded RNA-dependent protein kinase (PKR) has been implicated in interferon (IFN) induction, antiviral response and tumor suppression. We have generated mice devoid of functional PKR (Pkr%). Although the mice are physically normal and the induction of type I IFN genes by poly(I).poly(C) (pIC) and virus is unimpaired, the antiviral response induced by IFN-gamma and pIC was diminished. However, in embryo fibroblasts from Pkr knockout mice, the induction of type I IFN as well as the activation of NF-kappa B by pIC, were strongly impaired but restored by priming with IFN. Thus, PKR is not directly essential for responses to pIC, and a pIC-responsive system independent of PKR is induced by IFN. No evidence of the tumor suppressor activity of PKR was demonstrated.

Analysis of amount, expenditures and indications of drug and blood product prescriptions at surgical intensive care units

Analysis of indication-related drug prescription patterns is of particular interest with regard to rising costs of the health service being also reflected in higher expenditures for drugs at the University Hospital of the Friedrich-Schiller-University Jena. This is especially important at ICU's, since treatments in patients with acute or chronic multiorgan failure are very expensive. Over a period of 4 months in 1994 the indication-related drug consumption of 2 surgical ICU's of the University of Jena has been recorded and analyzed using a notebook-PC. The total costs of these drugs and blood products, which caused 80% of total costs in the last year, came up to 1,144,773 DM for 465 patients. Nearly two thirds of the recorded expenditures were caused in patients with severe trauma or with acute bleeding. The 10 leading substances (antithrombin III, human albumin 20%, prothrombine complex, etc.) represent 67% of total costs including blood products, antibiotics/antimycotics and IgM enriched intravenous immunoglobulines. Therefore, the indications of these drugs in particular have been further investigated. During and after the study the results have been discussed with the treating medical staff leading to new therapy recommendations. Until the end of 1994 a remarkable cost saving could already be achieved for some drugs by more critical and purposeful use providing same high standard of medical treatment. Blood products have to be included into analyses of indication-related drug administration on the meaning of high costs, difficulties of accurate indication, and possibly undesired side-effects. However, medical and ethical aspects, e.g. minimizing of side-effects, have to take priority over pharmacoeconomical considerations especially in intensive care medicine.

Nuclear matrix condensation and c-myc and c-fos expression are specifically altered in culture rat hepatocytes after exposure to cyproterone acetate and phenobarbital

Regenerative or hyperplastic growth promotes carcinogenesis and can be induced by many nongenotoxic carcinogens. The mitogenic potential of the rodent liver tumor promoters, cyproterone acetate and phenobarbital was investigated in primary rat hepatocyte cultures. Two premitotic markers were analyzed, the expression of two immediate-early genes (c-fos and c-myc) and the decrease in the nuclear quinacrine dihydrochloride fluorescence indicative for a G0-G1 cell cycle shift. C-fos expression and decrease in nuclear fluorescence could be induced by both chemicals, phenobarbital being the lesser potent, whereas c-myc expression was only inducible by cyproterone acetate. In situ hybridization with c-myc revealed that both chemicals enhanced c-myc mRNA levels in individual cells, however the number of responding hepatocytes was increased by cyproterone acetate only. The chemical-induced premitotic changes in hepatocytes were highly specific in terms of affected genes and ploidy levels of responding hepatocytes.

Partial restoration of pre-transformation levels of lysyl oxidase and transin mRNAs in phenotypic ras revertants

Neoplastic transformation mediated by ras oncogenes is associated with deregulated expression of genes encoding, for example, various proteases, lysyl oxidase, and smooth-muscle alpha-actin. To define the role of these genes in the initiation or maintenance of the ras-transformed state, we compared their steady-state mRNA levels in two different sets of preneoplastic fibroblast lines, ras-transformed clones, and phenotypic revertants derived from them. Compared with the preneoplastic fibroblasts, the ras-transformed derivatives exhibited elevated levels of cathepsin L (major excreted protein), transin (stromelysin I, matrix metalloproteinase-3), and collagenase I (matrix metalloproteinase-1) mRNA but undetectable levels of lysyl oxidase mRNA. Partial restoration of lysyl oxidase transcription was observed in four of five phenotypic revertants derived from rat FE-8 and NIHpEJcl3 cells. The elevated levels of transin mRNA found in NIHpEJcl3 cells were diminished to the pretransformation level in interferon revertants but were not reduced in phenotypic rat FE-8 revertants expressing a high level of the ras oncoprotein. High steady-state levels of collagenase I mRNA were dependent on ras expression but were not closely associated with the transformed phenotype. High levels of cathepsin L mRNA were associated with neither high ras expression nor neoplastic transformation. The downregulation of smooth-muscle alpha-actin, characteristic of transformed cell lines, was not reversible in phenotypic revertants.