Evaluation of different biomarkers to predict individual radiosensitivity in an inter-laboratory comparison--lessons for future studies

Radiotherapy is a powerful cure for several types of solid tumours, but its application is often limited because of severe side effects in individual patients. With the aim to find biomarkers capable of predicting normal tissue side reactions we analysed the radiation responses of cells from individual head and neck tumour and breast cancer patients of different clinical radiosensitivity in a multicentric study. Multiple parameters of cellular radiosensitivity were analysed in coded samples of peripheral blood lymphocytes (PBLs) and derived lymphoblastoid cell lines (LCLs) from 15 clinical radio-hypersensitive tumour patients and compared to age- and sex-matched non-radiosensitive patient controls and 15 lymphoblastoid cell lines from age- and sex- matched healthy controls of the KORA study. Experimental parameters included ionizing radiation (IR)-induced cell death (AnnexinV), induction and repair of DNA strand breaks (Comet assay), induction of yH2AX foci (as a result of DNA double strand breaks), and whole genome expression analyses. Considerable inter-individual differences in IR-induced DNA strand breaks and their repair and/or cell death could be detected in primary and immortalised cells with the applied assays. The group of clinically radiosensitive patients was not unequivocally distinguishable from normal responding patients nor were individual overreacting patients in the test system unambiguously identified by two different laboratories. Thus, the in vitro test systems investigated here seem not to be appropriate for a general prediction of clinical reactions during or after radiotherapy due to the experimental variability compared to the small effect of radiation sensitivity. Genome-wide expression analysis however revealed a set of 67 marker genes which were differentially induced 6 h after in vitro-irradiation in lymphocytes from radio-hypersensitive and non-radiosensitive patients. These results warrant future validation in larger cohorts in order to determine parameters potentially predictive for clinical radiosensitivity.

A radiation-induced gene expression signature as a tool to predict acute radiotherapy-induced adverse side effects

The majority of patients tolerate radiotherapy well, but some of them suffer from severe side effects. To find genes possibly predictive for radiosensitivity, mRNA profiles were generated before and 6h after in vitro irradiation with 5Gy. We analyzed lymphocytes from four head and neck and eight breast cancer patients with strong acute radiation toxicity and from 12 matching normal reacting patients in a blind study. Expression was also measured in lymphocyte subpopulations and Epstein-Barr transformed lymphocytes. Radiation response in whole lymphocyte populations was most similar to that of B cells. In peripheral blood lymphocytes of all patients; 153 genes were identified which were statistically significantly altered by a fold change of more than 50% by irradiation. The signatures of radio-responsive genes differed tremendously between primary and transformed cells. Pathway analysis revealed genes involved in p53 signalling, cell cycle control and apoptosis in response to radiation in primary lymphocytes. In these cells, a set of 67 radiation-induced genes was identified capable of differentiating between severe radiosensitive and normal reacting patients. More than one third of such classifying genes belong to the group of apoptosis or cell cycle regulating genes. The classifying potential of the expression signature has now to be validated in further patient cohorts.

[Colocutaneous fistula after a PEG procedure with introducer technique and gastropexy]

INTRODUCTION

The pull-PEG (percutaneous endoscopic gastrostomy) is the most commonly used procedure for PEG placement. Alternative methods may be used in patients with an obstructed oesophagus. We here present the case of an unusual complication during PEG placement with the new introducer technique and gastropexy.

CASE REPORT

A 74-year-old men with progressive thymus cell carcinoma was referred for a PEG procedure. Since the tumour stenosis in the oesophagus was only passable with a slim-sight endoscope (5,9 mm), we decided in favour of the direct PEG method with gastropexy. The procedure was performed without any complications. 35 days later we changed the balloon catheter and were able to easily inflate the balloon. Surprisingly, the X-ray performed thereafter, revealed a misplacement of the catheter in the colon without any notable contrast medium in the stomach. Although the patient expressed no complaints, he underwent surgery on the same day proving the colocutaneous fistula. There were no signs of peritonitis. The patient's postoperative recovery was uneventful.

DISCUSSION

Pull-PEG requires an intact oesophageal passage. The spread of bacteria and tumour cells is a possible risk factor. Direct punction PEG might be better in these cases. This method is not a standard procedure, but the recent implementation of an additional gastropexy represents a significant improvement. We experienced a rare complication, which was first described in 1987. However, this case is the first documented complication in association with gastropexy. This case shows that even gastropexy does not prevent colon interposition. Therefore, an endoscopic or radiological control of the tube placement after changing seems to be necessary.

Aluminum toxicity and forest decline

The rate of root elongation in seedlings of Picea abies was drastically inhibited by exposure to AlCl(3) at 800 or 1200 mumol/dm(3) in nutrient solutions. A 35-day exposure to Al at 700 mumol/dm(3) reduced Mg and Ca in roots and needles of the seedlings. The Mg content of needles was reduced to levels considered to be critical for Mg deficiency. In investigations of (45)Ca uptake into roots, exposure to Al at 100-800 mumol/dm(3) reduced (45)Ca uptake by 77-92%, respectively. By using x-ray microanalysis, the distribution of Al, Mg, Ca, and K was found to be similar in roots of Picea abies seedlings grown in solution culture and in roots collected from declining spruce stands at Solling, F.R.G. In solution culture Al displaced Mg and Ca in the root cortex. A mechanism of Al toxicity for root growth and ion uptake is proposed, and its relevance to forest decline is discussed.

Quantitative X-ray microanalysis of hydrogen peroxide within plant cells

Using quantitative X-ray microanalysis in combination with CeCl3-based cytochemical staining of hydrogen peroxide (H2O2) we have developed a new solution for quantification of H2O2 at the subcellular level. Quantitative X-ray microanalysis of plastic-embedded leaves of Populus euphratica Oliv. showed that the obtained cerium precipitates by CeCl3 staining were the mixture of cerium perhydroxides and cerium phosphate, in which the fractions of CePO4 were: (1) 52-74% in cell walls of fresh leaf segments, and (2) 34-70% in the cytoplasm in 10 mM H2O2-treated leaf segments that were previously freeze-dried. Taking the concentration of cerium phosphate as staining background, we reached the cellular concentration of cerium perhydroxides and the corresponding concentration of H2O2. Results showed that H2O2 was present in the cytoplasm of rehydrated leaf segments (29-58 mM), but in fresh leaves, H2O2 was observed in the walls of all measured cell types (17-74 mM).

Non-conservative homologous recombination in human B lymphocytes is promoted by activation-induced cytidine deaminase and transcription

During secondary immunoglobulin (Ig) diversification in vertebrates, the sequence of the variable region of Ig genes may be altered by templated or non-templated mechanisms. In both cases, cytidine deamination by activation-induced cytidine deaminase (AID) in the transcribed Ig loci leads to DNA lesions, which are repaired by conservative homologous recombination (HR) during Ig gene conversion, or by non-templated mutagenesis during somatic hypermutation. The molecular basis for the differential use of these two pathways in different species is unclear. While experimental ablation of HR in avian cells performing Ig gene conversion may promote a switch to somatic hypermutation, the activity of HR processes in intrinsically hypermutating mammalian cells has not been measured to date. Employing a functional HR assay in human germinal centre like B cell lines, we detect elevated HR activity that can be enhanced by transcription and AID. Products of such recombination events mostly arise through non-conservative HR pathways, while the activity of conservative HR is low to absent. Our results identify non-conservative HR as a novel DNA transaction pathway promoted by AID and suggest that somatic hypermutation in germinal centre B cells may be based on a physiological suppression of conservative HR.

Ionic homeostasis and reactive oxygen species control in leaves and xylem sap of two poplars subjected to NaCl stress

We investigated the effects of increasing soil NaCl concentration on intracellular compartmentalization of salt and on the activities of antioxidant enzymes (superoxide dismutase (SOD), ascorbic peroxidase (APX), catalase (CAT) and glutathione reductase (GR)) and their role in the regulation of reactive oxygen species (ROS; O(2)(-*) and H(2)O(2)) in leaves and xylem sap of salt-tolerant Populus euphratica Oliv. and salt-sensitive P. popularis cv. 35-44. Mesophyll cells of P. euphratica exhibited a high capacity for NaCl exclusion and compartmentalization of salt in vacuoles compared with P. popularis. In P. popularis, the salt treatment resulted in large accumulations of Na(+) and Cl(-) in leaves that induced significant increases in O(2)(-*) and H(2)O(2) production despite marked increases in the activities of antioxidant enzymes in leaves and xylem sap. Separation of the isoforms of leaf SOD, APX and CAT by polyacrylamide gel electrophoresis followed by in-gel activity staining revealed that the salt-induced activities of APX and CAT were the result of increases in activities of all the isoenzymes. Leaf injury and shedding of aged leaves occurred following the oxidative burst in P. popularis, indicating that the increased activities of antioxidant enzymes in P. popularis were insufficient to counter the harmful effects of ROS at high soil NaCl concentrations. Unlike P. popularis plants, P. euphratica plants did not exhibit an oxidative burst in response to the NaCl treatments, because of (1) a high salt exclusion capacity and effective compartmentalization of salt in vacuoles, and (2) up-regulation of antioxidant enzymatic activities after the onset of salt stress. We conclude that P. euphratica plants subjected to saline conditions control ROS homeostasis through two pathways: (1) by maintaining cellular ionic homeostasis and thereby limiting the NaCl-induced enhancement of ROS production under long-term saline conditions; and (2) by rapidly up-regulating antioxidant defenses to prevent oxidative damage.

Measurement of cation exchange capacity (CEC) of plant cell walls by X-ray microanalysis (EDX) in the transmission electron microscope

Cation exchange capacity (CEC) characterizes the number of fixed negative charges of plant cell walls and is an important parameter in studies dealing with the uptake of ions into plant tissues, especially in roots. Conventional methods of CEC determination use bulk tissue, the results are the mean of many cells, and differences in the CEC of different tissue types are masked. Energy-dispersive microanalysis (EDX) in the transmission electron microscope allows CEC determinations on much finer scales. Shoot and fine root tissue of Picea abies was acid washed to remove exchangeable cations. Tissue blocks or semithin tissue sections were loaded with 0.2 mM CaCl2, AlCl3, or Pb(NO3)2 at pH 4.0. The amount of Ca, Al, or Pb adsorbed to the exchange sites of cell walls was determined by EDX. The CEC of cell walls of different tissue types was highly different, ranging in shoot tissues from 0 to 856 mM Ca and 5.8 to 1463 mM Al (block loading) or 4.3 to 1116 mM Ca and 0 to 2830 mM Al (section loading). In root tissue, Pb adsorption to semithin sections yielded CEC values between 29.1 and 954 mM Pb. In most P. abies shoot tissues, the binding capacity was clearly higher for Al than for Ca.

Paxillus involutus mycorrhiza attenuate NaCl-stress responses in the salt-sensitive hybrid poplar Populusxcanescens

In order to characterise the effect of ectomycorrhiza on Na+-responses of the salt-sensitive poplar hybrid Populus x canescens, growth and stress responses of Paxillus involutus (strain MAJ) were tested in liquid cultures in the presence of 20 to 500 mM NaCl, and the effects of mycorrhization on mineral nutrient accumulation and oxidative stress were characterised in mycorrhizal and non-mycorrhizal poplar seedlings exposed to 150 mM NaCl. Paxillus involutus was salt tolerant, showing biomass increases in media containing up to 500 mM NaCl after 4 weeks growth. Mycorrhizal mantle formation on poplar roots was not affected by 150 mM NaCl. Whole plant performance was positively affected by the fungus because total biomass was greater and leaves accumulated less Na+ than non-mycorrhizal plants. Energy dispersive X-ray microanalysis using transmission electron microscopy analysis of the influence of mycorrhization on the subcellular localisation of Na+ and Cl- in roots showed that the hyphal mantle did not diminish salt accumulation in root cell walls, indicating that mycorrhization did not provide a physical barrier against excess salinity. In the absence of salt stress, mycorrhizal poplar roots contained higher Na+ and Cl- concentrations than non-mycorrhizal poplar roots. Paxillus involutus hyphae produced H2O2 in the mantle but not in the Hartig net or in pure culture. Salt exposure resulted in H2O2 formation in cortical cells of both non-mycorrhizal and mycorrhizal poplar and stimulated peroxidase but not superoxide dismutase activities. This shows that mature ectomycorrhiza was unable to suppress salt-induced oxidative stress. Element analyses suggest that improved performance of mycorrhizal poplar under salt stress may result from diminished xylem loading of Na+ and increased supply with K+.

Populus euphratica displays apoplastic sodium accumulation, osmotic adjustment by decreases in calcium and soluble carbohydrates, and develops leaf succulence under salt stress

Populus euphratica Olivier is known to exist in saline and arid environments. In this study we investigated the physiological mechanisms enabling this species to cope with stress caused by salinity. Acclimation to increasing Na+ concentrations required adjustments of the osmotic pressure of leaves, which were achieved by accumulation of Na+ and compensatory decreases in calcium and soluble carbohydrates. The counterbalance of Na+/Ca2+ was also observed in mature leaves from field-grown P. euphratica trees exposed to an environmental gradient of increasing salinity. X-ray microanalysis showed that a primary strategy to protect the cytosol against sodium toxicity was apoplastic but not vacuolar salt accumulation. The ability to cope with salinity also included maintenance of cytosolic potassium concentrations and development of leaf succulence due to an increase in cell number and cell volume leading to sodium dilution. Decreases in apoplastic and vacuolar Ca2+ combined with suppression of calcineurin B-like protein transcripts suggest that Na+ adaptation required suppression of calcium-related signaling pathways. Significant increases in galactinol synthase and alternative oxidase after salt shock and salt adaptation point to shifts in carbohydrate metabolism and suppression of reactive oxygen species in mitochondria under salt stress.

Dual function of membrane-bound heat shock protein 70 (Hsp70), Bag-4, and Hsp40: protection against radiation-induced effects and target structure for natural killer cells

CX+/CX- and Colo+/Colo- tumor sublines with stable heat shock protein 70 (Hsp70) high and low membrane expression were generated by fluorescence activated cell sorting of the parental human colon (CX2) and pancreas (Colo357) carcinoma cell lines, using an Hsp70-specific antibody. Two-parameter flow cytometry revealed that Hsp70 colocalizes with Bag-4, also termed silencer of death domain, not only in the cytosol but also on the plasma membrane. After nonlethal gamma-irradiation, the percentage of membrane-positive cells and the protein density of Hsp70 and Bag-4 were found to be strongly upregulated in carcinoma sublines with initially low expression levels (CX-, Colo-). Membrane expression of Hsp70 was also elevated in Bag-4 overexpressing HeLa cervix carcinoma cells when compared to neo-transfected cells. In response to gamma-irradiation, neo-transfected HeLa cells behaved like Hsp70/Bag-4 low-expressing CX- and Colo-, and Bag-4-transfected HeLa cells like Hsp70/Bag-4 high-expressing carcinoma sublines CX+ and Colo+. Immunoprecipitation studies further confirmed colocalization of Hsp70 and Bag-4 but also point to an association of Hsp70 and Hsp40 on the plasma membrane of CX+ and Colo+ cells; on CX- and Colo- tumor sublines, Hsp40 was detectable in the absence of Hsp70 and Bag-4. Other co-chaperones including Hsp60 and Hsp90 were neither found on the cell surface of CX+/CX-, Colo+/Colo- nor on HeLa neo-/HeLa Bag-4-transfected tumor cells. Functionally, Hsp70/Bag-4 and Hsp70/Hsp40 membrane-positive tumor cells appeared to be better protected against radiation-induced effects, including G2/M arrest and growth inhibition, on the one hand. On the other hand, membrane-bound Hsp70, but neither Bag-4 nor Hsp40, served as a recognition site for the cytolytic attack mediated by natural killer cells.

Expressional and functional studies of Wolframin, the gene function deficient in Wolfram syndrome, in mice and patient cells

Wolfram Syndrome is an autosomal recessive degenerative disorder of the neuroendocrine system. Diabetes mellitus is its lead symptom. Patients show mutations in the wolframin (WFS1) gene coding for a hydrophobic transmembrane protein of 890 amino acids. This protein was preliminarily localised in the endoplasmatic reticulum (ER) in cells of mice and rats. Mice lacking the WFS1 gene display degeneration of pancreatic beta-cells following induction of ER stress. We here used antibodies against substructures of the wolframin protein in order to analyse its expression and localisation. Expression was detected in both pancreatic beta-cells and the limbic system of mice. Using the rat insulinoma cell line RIN 5AH and fractionated mouse brain tissue, we confirmed wolframin localisation to the endoplasmic reticulum. Expression profiling on patient's primary fibroblasts revealed down-regulation of the diabetes associated plasma membrane glycoprotein (PC-1) gene, and up-regulation of fibulin-3, a gene connected to senescence. However, cell proliferation was indistinguishable from non-mutated cells. In contrast to data obtained on murine pancreatic islets, we found no increased apoptosis following induction of ER stress but rather by staurosporine treatment in the absence of WFS1 function. This indicates a new role of WFS1 deficiency in programmed cell death.

Spontaneous homologous recombination is decreased in Rad51C-deficient hamster cells

The Chinese hamster cell mutant, CL-V4B that is mutated in the Rad51 paralog gene, Rad51C (RAD51L2), has been described to exhibit increased sensitivity to DNA cross-linking agents, genomic instability, and an impaired Rad51 foci formation in response to DNA damage. To directly examine an effect of the Rad51C protein on homologous recombination (HR) in mammalian cells, we compared the frequencies and rates of spontaneous HR in CL-V4B cells and in parental wildtype V79B cells, using a recombination reporter plasmid in host cell reactivation assays. Our results demonstrate that HR is reduced but not abolished in the CL-V4B mutant. We thus, provide direct evidence for a role of mammalian Rad51C in HR processes. The reduced HR events described here help to explain the deficient phenotypes observed in Rad51C mutants and support an accessory role of Rad51C in Rad51-mediated recombination.

Effects of lactulose and polyethylene glycol on colonic transit

BACKGROUND

The effects of lactulose and polyethylene glycol on colonic transit are poorly established.

AIM

To assess the effects of these laxatives on colonic transit in normal subjects.

METHODS

Colonic transit (mean residence time, cumulative counts in stool, counts remaining in the proximal or distal colon) was measured scintigraphically in normal subjects on the second and third day of a 3-day ingestion of 67-134 g/day lactulose, or 59 g/day polyethylene glycol.

RESULTS

At similar stool weight (lactulose: 653 +/- 120 g/day; polyethylene glycol: 522 +/- 66 g/day), transit was significantly slower during 99 g/day lactulose when compared with 59 g/day polyethylene glycol; this was most pronounced in the distal colon (mean residence time: lactulose - 403 +/- 55 min; polyethylene glycol - 160 +/- 41.9 min). Short chain fatty acid concentration in 24-h stool correlated significantly with counts remaining in the distal colon at 12 h (r = 0.79, P = 0.001). Increasing lactulose doses were significantly associated with increasing stool weight (r = 0.79) and shorter mean residence time in the total (r = -0.56) and distal colon (r = -0.64). The sum of faecal carbohydrates plus short chain fatty acids was associated with stool weight (r = 0.95, P < 0.001).

CONCLUSION

Lactulose accelerates colonic transit. However, compared with polyethylene glycol, transit during lactulose is prolonged.

The rate of extrachromosomal homologous recombination within a novel reporter plasmid is elevated in cells lacking functional ATM protein

Homologous recombination between identical stretches of DNA depends on the coordinated action of many tightly regulated proteins. Cellular defects in homologous recombination are strongly associated with increased genomic instability and tumorigenesis. In cells of the cancer-prone syndrome ataxia telangiectasia (A-T), increased intrachromosomal recombination has been demonstrated, while extrachromosomal recombination has been discussed controversially. We constructed a novel, episomally replicating pGrec recombination vector containing two mutated alleles of the enhanced green fluorescent protein (eGFP) gene. Homologous recombination can reconstitute functional wildtype eGFP, thus allowing detection of recombination events based on cellular eGFP fluorescence. Using an isogenic cell pair of A-T fibroblasts and derivatives complemented by an ATM expression vector, we were able to demonstrate in A-T cells high extrachromosomal recombination rates, which are suppressed upon ectopic ATM expression. We thus found that ATM deficiency increases spontaneous recombination not only in intrachromosomal but also in extrachromosomal substrates, suggesting that lack of ATM increases homologous recombination independent of the chromatin structure.

Transfer standard for beta decay radionuclides in radiotherapy

The measurement of the activity of therapeutic radiopharmaceuticals prior to the administration to patients is normally achieved via the use of radionuclide calibrators. An accurate measurement of the activity of pure beta-emitters is complex. Calibration problems can be solved by combining a primary calibration with a 90Y reference solution and a 90Sr/90Y transfer standard with a solid source, simulating geometric effects caused by high energetic beta radiation. The recent development of a 90Sr/90Y transfer standard for this purpose is reported.

Compatible and incompetent Paxillus involutus isolates for ectomycorrhiza formation in vitro with poplar (Populus x canescens) differ in H2O2 production

Isolates of Paxillus involutus (Batsch) Fr. collected from different hosts and environmental conditions were screened for their ability to form ectomycorrhizal symbiosis with hybrid poplar P. x canescens (= Populus tremula L. x P. alba) in vitro. The ability to form ectomycorrhiza varied between the fungal isolates and was not correlated with the growth rate of the fungi on agar-based medium. The isolate MAJ, which was capable of mycorrhiza synthesis under axenic conditions, and the incompetent isolate NAU were characterized morphologically and anatomically. MAJ formed a typical hyphal mantle and a Hartig net, whereas NAU was not able to penetrate the host cell walls and caused thickenings of the outer cell walls of the host. MAJ, but not NAU, displayed strong H2O2 accumulation in the outer hyphal mantle. Increases in H2O2 in the outer epidermal walls and adjacent hyphae of the incompetent isolate were moderate. No increases of H2O2 in response to the mycobionts were found inside roots. Suggested functions of H2O2 production in the outer hyphal mantle of the compatible interaction are: growth regulation of the host's roots, defence against other invading microbes, or increasing plant-innate immunity. The system established here for P. x canescens compatible and incompetent fungal associations will be useful to take advantage of genomic information now available for poplar to study tree-fungal interactions at the molecular and physiological level.

Overexpression of the 'silencer of death domain', SODD/BAG-4, modulates both TNFR1- and CD95-dependent cell death pathways

The involvement of SODD/BAG-4 was studied in TNFR1 signaling, using SODD/BAG-4- overexpressing HeLa cells as a cellular model. Stable transfection of a SODD/BAG-4 cDNA leads to increased levels of the full-length 70-kDa protein and additional C-terminal fragments as well as altered expression of BAG-1. Concomitantly, the protein amounts of both the TNFR1 and, unexpectedly, the CD95 receptors are elevated. These biochemical changes are paralleled and confirmed by a reduced cellular sensitivity to treatment with extracellular TNFalpha and CD95 ligand. Moreover, ATP depletion by oligomycin is less toxic in SODD/BAG-4 overexpressing clones. The radiosensitivity is reduced in some, but not in all of these clones. Our results indicate that SODD/BAG-4 is not only a silencer of TNFR1 but also a modulator of CD95 activity, regulating the balance of both death-promoting and -depressing signals.

Formation of higher-order nuclear Rad51 structures is functionally linked to p21 expression and protection from DNA damage-induced apoptosis

After exposure of mammalian cells to DNA damage, the endogenous Rad51 recombination protein is concentrated in multiple discrete foci, which are thought to represent nuclear domains for recombinational DNA repair. Overexpressed Rad51 protein forms foci and higher-order nuclear structures, even in the absence of DNA damage, in cells that do not undergo DNA replication synthesis. This correlates with increased expression of the cyclin-dependent kinase (Cdk) inhibitor p21. Following DNA damage, constitutively Rad51-overexpressing cells show reduced numbers of DNA breaks and chromatid-type chromosome aberrations and a greater resistance to apoptosis. In contrast, Rad51 antisense inhibition reduces p21 protein levels and sensitizes cells to etoposide treatment. Downregulation of p21 inhibits Rad51 foci formation in both normal and Rad51-overexpressing cells. Collectively, our results show that Rad51 expression, Rad51 foci formation and p21 expression are interrelated, suggesting a functional link between mammalian Rad51 protein and p21-mediated cell cycle regulation. This mechanism may contribute to a highly effective recombinational DNA repair in cell cycle-arrested cells and protection against DNA damage-induced apoptosis.

TEL1 from Saccharomyces cerevisiae suppresses chromosome aberrations induced by ionizing radiation in ataxia-telangiectasia cells without affecting cell cycle checkpoints

The TEL1 gene from Saccharomyces cerevisiae has been shown to be the closest sequence homologue to ATM, the gene mutated in ataxia-telangiectasia (A-T) patients. Functional homology shared between the ATM and Tell proteins has recently been demonstrated based on heterologous expression of the TEL1 gene in human cells derived from A-T patients. TEL1 expression complemented specific cellular A-T deficiencies, i.e. increased radiation-induced apoptosis, telomere shortening and spontaneous hyperrecombination. The mechanism of cellular A-T complementation by TEL1 appears to be independent of p53-dependent signaling cascades, since the deficiency of A-T cells to properly induce p53 upon ionizing radiation was not corrected by TEL1. We now find that the basic number of chromosome aberrations is increased and the number of radiation-induced chromosome aberrations is suppressed in A-T cells upon TEL1 expression. In cell cycle analyses, we find no changes in basic cell cycle distribution or in radiation-induced cell cycle checkpoints following TEL1 expression. We conclude that the radioprotective function of the Tel1 protein includes suppression of apoptosis and suppression of chromosome aberrations, and that both cellular end-points can be uncoupled from ionizing radiation-induced cell cycle checkpoints.

Interferon in multiple myeloma--summary of treatment results and clinical implications

Even though interferon (IFN) has been used in myeloma treatment for more than two decades, its efficacy is still controversial. Meta-analysis of randomized trials is based either on individual patient data or on published data. We performed meta-analyses on published and reported data using, in addition to the standard method, three independent methods of evaluating Kaplan-Meier curves. Thirty randomized trials on IFN induction or maintenance treatment were meta-analyzed. Combined IFN-chemotherapy induction treatment resulted in significant increases of repsonse rates (6.6%), as well as median relapse-free (4.8 months) and overall survival (3.1 months). IFN maintenance treatment prolonged median relapse-free survival by 4.4 months, median overall survival by 7.9 months. Drug costs of IFN per 1-year survival gain were US$ 42,236.19 for induction therapy and US$ 18,114.95 for maintenance treatment. To conclude, our results a are in accordance with those obtained from individual patient data by the Myeloma Trialists' Collaborative Group. Because of the consistent, though limited, improved trial outcomes, IFN treatment should be suggested to all myeloma patients who might benefit from it.

Interferon-alpha treatment in multiple myeloma: meta-analysis of 30 randomised trials among 3948 patients

BACKGROUND

After two decades of interferon (IFN) treatment in myeloma patients and many randomised clinical trials, no definite proof of its benefits exists. This meta-analysis of all available relevant published data tests the differences between IFN and control arms in a large patient population and addresses the issue of cost-effectiveness.

PATIENTS AND METHODS

Meta-analysis was performed on 17 trials among 2333 patients who received IFN-chemotherapy induction treatment or chemotherapy alone and on 13 trials among 1615 patients on IFN maintenance therapy or without treatment. Response rates and parameters of published Kaplan Meier relapse-free and overall survival curves were analysed.

RESULTS

Patients in IFN arms showed significantly better results in all investigated parameters: IFN-chemotherapy induction treatment yielded 6.6% higher response rates (2P < 0.002) as well as 4.8-month and 3.1-month prolongations of relapse-free (P < 0.01) and overall survival (P < 0.01), respectively. Interferon maintenance therapy lead to 4.4-month (P < 0.01) and 7.0-month (P < 0.01) prolongations of relapse-free and overall survival, respectively. Meta-analysis of all IFN trials combined resulted in 4.6-month and 3.7-month IFN-related gains in relapse-free and overall survival, respectively. As early as 6 and 12 months after the start of IFN treatment, percentages of cumulative relapse-free and overall survival were always significantly higher in IFN trial arms. IFN drug expenses for a one-year survival gain, as determined from AUCs of best-fitted Gompertz functions of IFN and control survival curves, were estimated to be US$42,482.28 for induction therapy and US$18,968.16 for maintenance treatment.

CONCLUSIONS

Significantly superior outcomes were consistently found in IFN trial arms by meta-analysis of published data. These results are in accordance with a concomittantly conducted meta-analysis on individual patient data but were much easier to accrue. Taking all our results into account. i.e., the consistently significant, although limited, improvement of clinical outcomes and its acceptable cost-effectiveness, IFN treatment of patients with multiple myeloma seems worthwhile to be considered.

The yeast TEL1 gene partially substitutes for human ATM in suppressing hyperrecombination, radiation-induced apoptosis and telomere shortening in A-T cells

Homozygous mutations in the human ATM gene lead to a pleiotropic clinical phenotype of ataxia-telangiectasia (A-T) patients and correlating cellular deficiencies in cells derived from A-T donors. Saccharomyces cerevisiae tel1 mutants lacking Tel1p, which is the closest sequence homologue to the ATM protein, share some of the cellular defects with A-T. Through genetic complementation of A-T cells with the yeast TEL1 gene, we provide evidence that Tel1p can partially compensate for ATM in suppressing hyperrecombination, radiation-induced apoptosis, and telomere shortening. Complementation appears to be independent of p53 activation. The data provided suggest that TEL1 is a functional homologue of human ATM in yeast, and they help to elucidate different cellular and biochemical pathways in human cells regulated by the ATM protein.

Deletion of 13q14 remains an independent adverse prognostic variable in multiple myeloma despite its frequent detection by interphase fluorescence in situ hybridization

Interphase fluorescence in situ hybridization (FISH) studies of chromosomal region 13q14 were performed to investigate the incidence and clinical importance of deletions in multiple myeloma (MM). Monoallelic deletions of the retinoblastoma-1 (rb-1) gene and the D13S319 locus were observed in 48 of 104 patients (46.2%) and in 28 of 72 (38.9%) patients, respectively, with newly diagnosed MM. FISH studies found that 13q14 was deleted in all 17 patients with karyotypic evidence of monosomy 13 or deletion of 13q but also in 9 of 19 patients with apparently normal karyotypes. Patients with a 13q14 deletion were more likely to have stage III disease (P =.022), higher serum levels of beta(2)-microglobulin (P =.059), and a higher percentage of bone marrow plasma cells (P =.085) than patients with a normal 13q14 status on FISH analysis. In patients with a deletion of 13q14, myeloma cell proliferation (Ki-67) was markedly increased (22.0% +/- 6.9% compared with 15.6% +/- 8.2% in patients without the deletion; P =.0008). Evaluation of bromodeoxyuridine incorporation in 5 patients revealed that both rb-1-deleted and rb-1-normal MM subpopulations were proliferative. The presence of a 13q14 deletion on FISH analysis was associated with a significantly lower rate of response to conventional-dose chemotherapy (40.8% compared with 78. 6%; P =.009) and a shorter overall survival (24.2 months compared with > 60 months; P <.005) than in patients without the deletion. Multivariate analysis of prognostic factors confirmed the independent predictive value of 13q14 deletions for shortened survival. In conclusion, deletions of 13q14 are frequently detected by interphase FISH in patients with newly diagnosed MM, correlate with increased proliferative activity, and represent an independent adverse prognostic feature in MM. (Blood. 2000;95:1925-1930)

Rapid enzyme-linked immunoassay for detection of Salmonella in food and feed products: performance testing program

The BIOLINE Salmonella ELISA Test for Salmonella spp., which is a rapid, easy, and convenient assay was evaluated for use in detecting Salmonella in foods and feeds. Each food matrix or feed was artificially contaminated with low levels of Salmonella. Twenty different matrixes were studied and 20 different Salmonella strains from a broad variety of serogroups (B, C, D, E, F, G, H, I, M, O, P, and U) were used. The EUSA Test kit detected levels as low as 1 cfu/25 g sample with at least 4 of the 20 matrixes tested. The test kit is applicable to all sample types tested. The BIOLINE Salmonella ELISA Test kit has been granted AOAC-RI performance tested status.

Predictive role of interphase cytogenetics for survival of patients with multiple myeloma

PURPOSE

Recent metaphase cytogenetic studies suggested that specific chromosomal abnormalities are of prognostic significance in patients with multiple myeloma (MM). Because the true incidence of chromosomal abnormalities in MM is much higher than that detected by metaphase analysis, we used interphase fluorescence in situ hybridization (FISH) to determine the prognostic value of specific chromosomal aberrations.

PATIENTS AND METHODS

Bone marrow plasma cells from 89 previously untreated patients with MM were studied consecutively by FISH to detect the deletions of 13q14, 17p13, and 11q and the presence of t(11;14)(q13;q32). FISH results were analyzed in the context of clinical parameters (response to treatment and survival after conventional-dose chemotherapy), and a multivariate analysis of prognostic factors was performed.

RESULTS

By FISH, the deletion of 13q14 occurred in 40 patients (44.9%), deletion of 17p13 in 22 (24.7%), and 11q abnormalities in 14 (15.7%; seven with t(11;14)). Deletions of 13q14 and 17p13 were associated with poor response to induction treatment (46.9% v 77.3% in those without deletions, P =.006 and 40.0% v 73.2%, P =.008, respectively) and short median overall survival (OS) time (24.2 v 88.1 months, P =. 008 and 16.2 v 51.3 months, P =.008, respectively). Short median OS time was also observed for patients with 11q abnormalities (13.1 v 41.6 months, P =.02). According to the number of unfavorable cytogenetic features (deletion of 13q14, deletion of 17p13, and aberrations of 11q) that were present in each patient (0 v 1 v 2 or 3), patients with significantly different OS times could be discriminated from one another (102.4 v 29.6 v 13.9 months, P <.001, respectively).

CONCLUSION

For patients with MM who were treated with conventional-dose chemotherapy, interphase FISH for 13q14, 17p13, and 11q provides prognostically relevant information in addition to that provided by standard prognostic factors. This observation may be considered for risk-adapted stratifications of MM patients in future clinical trials.

Neurological function during long-term therapy with recombinant interferon alpha

In 14 patients with myeloproliferative disorders associated with thrombocytosis, neurological and neuropsychological function were monitored prior to therapy with recombinant human interferon alpha (rIFN; dose 25 mU/week; range 10-35 mU/week) and after 3, 6, 9, and 12 months of treatment. No overt neurological side effects were observed except 1 case of cerebral insult, probably not treatment-related. Attention, memory function, and tapping improved significantly. The P2-N3 amplitudes of visually evoked potentials increased during normalization of platelet counts. Muscular strength and the amplitude of the compound muscle action potential of the median and peroneal nerves increased significantly in an inversely dose-related fashion. In patients with myeloproliferative disorders, long-term therapy with low to intermediate doses of rIFN does not seem to impair neurological function, but rather is associated with enhanced muscle power and the level of mental arousal.

Human fibroblasts transfected with an ATM antisense vector respond abnormally to ionizing radiation

ATM, the gene mutated in ataxia-telangiectasia (A-T), mediates multiple cellular responses to DNA damage. A-T homozygotes have a high risk of cancer and exhibit spontaneous chromosomal instability, and cultured A-T cells react abnormally to ionizing radiation. We have developed an ATM antisense vector that confers an A-T phenotype on normal cells. An episomal antisense vector was created that contained a 1.3 kb segment of the ATM cDNA, and was transfected into normal human fibroblasts. Intracellular levels of ATM protein were typically reduced 10-fold in antisense-expressing (GM639-46alpha) clones. GM639-46alpha clones exhibited the low threshold for radiation-induced apoptosis, low clonogenic survival, and cell cycle defects normally seen in A-T cells. Transfection with the corresponding ATM sense strand vector had no effect on the behavior of normal cells, and neither vector affected the behavior of A-T cells. Our results demonstrate that interference with ATM gene expression recreates the A-T phenotype in normal cells, and provide functional evidence linking the ATM gene to cellular DNA damage responses. The ATM antisense vector should prove a useful tool for studying ATM function in a variety of normal, mutant, and malignant cell lines.

Presence of a p53 gene deletion in patients with multiple myeloma predicts for short survival after conventional-dose chemotherapy

In multiple myeloma (MM), previous studies showed that mutations of the p53 gene are rare events in patients with newly diagnosed disease, but it is not known whether deletions of p53 are of any significance in MM. To address this question, we used interphase fluorescence in situ hybridization (FISH) with a DNA probe specific for the p53 locus at 17p13 and investigated bone marrow plasma cells from 72 patients with MM (59 patients = 81.9% before therapy). By FISH, deletions of p53, which were found to be predominantly monoallelic, were detected in 32.8% and 54.5% of patients with newly diagnosed and relapsed MM, respectively. Karyotypes from six of the patients with a p53 deletion by FISH showed a structural abnormality of 17p in only one of them. Additional FISH studies including a distal-17p probe (specific for the D17S34 locus) provided evidence for an interstitial deletion on 17p resulting in loss of p53 hybridization signals in myeloma cells. Among all 59 patients with newly diagnosed MM, presence of a p53 deletion was associated with stage III (P = .054), but not with other laboratory and clinical parameters. Patients with a p53 deletion had significantly shorter survival time compared with those without a deletion, both from the time of diagnosis (median 13.9 v 38.7 months; P < .0001) and from the time of initiation of induction treatment consisting of conventional dose chemotherapy (median 15.9 months v median not reached at 38 months; P < .0002). On stepwise multivariate regression analysis, presence of a p53 deletion was the most significant independent parameter predicting for shortened survival (P = .002). We conclude that a p53 gene deletion, which can be identified by interphase FISH in almost a third of patients with newly diagnosed MM, is a novel prognostic factor predicting for short survival of MM patients treated with conventional-dose chemotherapy.

Anemia of cancer patients: patient selection and patient stratification for epoetin treatment

Epoetin alfa is being used to treat patients with symptomatic anemia of cancer and to prevent or postpone chemotherapy-induced anemia in cancer treatment. As only approximately 50% of unselected anemic cancer patients respond sufficiently to epoetin alfa treatment, careful patient selection according to reliable prediction criteria is of great importance. Predictions of response to epoetin alfa treatment are based either on the degree of blunted erythropoietin response to the anemic condition or on indicators of responsiveness during the early treatment phase. The most accurate predictions of responsiveness, however, are derived from combinations of predictive factors. Combinations of synergistically acting hematopoietic growth factors, particularly epoetin alfa and granulocyte colony-stimulating factor, are beneficial to selected patients with myelodysplastic syndrome and may prolong survival in certain cases. Correction of anemia in cancer patients is particularly important because highly significant correlations have been reported between hemoglobin levels and quality of life in these patients.

Anemia in cancer patients

Chronic anemia in cancer patients is caused by several pathophysiologic mechanisms. Reduced numbers of erythroid progenitor cells in the bone marrow and increased levels of inflammatory cytokines, which suppress erythropoiesis, result in a lower proliferative response of the erythron to erythropoietin stimulation. Erythropoietin production by the kidney in response to tissue hypoxia is often blunted; as a result, serum erythropoietin levels may be inappropriately low with regard to the degree of anemia. Red blood cell survival may be shortened; impaired iron utilization is manifested by enhanced retention of iron in the reticuloendothelial system. Chronic anemia also may be induced by cancer treatment, such as nephrotoxic chemotherapy.

Gene for topoisomerase III maps within the Smith-Magenis syndrome critical region: analysis of cell-cycle distribution and radiation sensitivity

Smith-Magenis syndrome (SMS) is caused by an interstitial deletion of chromosome band 17p11.2 averaging 4-5 Mb. This deletion is likely to contain a large number of genes, each of which could potentially contribute toward the clinical phenotype. We report that the gene for topoisomerase III (hTOP3) is commonly deleted in SMS patients and maps between D17S447 and D17S258 on the short arm of chromosome 17. Cellular studies of SMS patient lymphoblasts and their respective parental cell lines were undertaken to determine the consequences of haploinsufficiency of hTOP3. Our studies indicate that hemizygosity for hTOP3 does not appreciably affect cell-cycle kinetics or activation of ionizing radiation-sensitive cell-cycle checkpoints. Furthermore, the induction of apoptosis in response to ionizing radiation in SMS and parental cells was similar. Our studies suggest that haploinsufficiency of hTOP3 does not have a major impact on the behavior of cells from SMS patients and may not play a significant role in the SMS phenotype.

Overexpression of a truncated human topoisomerase III partially corrects multiple aspects of the ataxia-telangiectasia phenotype

Ataxia-telangiectasia (A-T) is a recessive human disease characterized by radiation sensitivity, genetic instability, immunodeficiency, and high cancer risk. We previously used expression cloning to identify CAT4.5, a human cDNA that partially suppresses multiple aspects of the A-T phenotype upon transfection into cultured cells. Sequencing CAT4.5 revealed a 1.1-kb intronic fragment followed by a related ORF of 2.5 kb that encodes the near full-length ORF for hTOP3, the first mammalian topoisomerase III to be identified. Endogenous expression of hTOP3 was found in all human tissues tested. Both pCAT4.5 and an antisense hTOP3 construct were able to inhibit spontaneous and radiation-induced apoptosis in A-T fibroblasts, whereas overexpression of a full-length hTOP3 cDNA did not. We postulate that topoisomerase III may be deregulated in A-T cells and that CAT4.5 complements the A-T phenotype via a dominant-negative mechanism. Furthermore, functional correction of hyper-recombination in A-T cells by CAT4.5 supports the hypothesis that the hTOP3 topoisomerase is involved in the control of genomic stability, perhaps in concert with the Bloom or Werner syndrome DNA helicases.

Patient preferences for interferon alfa in multiple myeloma

PURPOSE

Interferon alfa treatment in multiple myeloma marginally improves relapse-free and overall survival. Often it does so at the expense of toxicity and financial cost. If patients are unwilling or unable to participate in the decision of whether to initiate such treatment, known patient preferences can serve as guidelines for the physician. We interviewed myeloma patients in the United States to obtain information that might facilitate medical decision-making.

PATIENTS AND METHODS

Three hundred fifty-five myeloma patients throughout the United States were interviewed by telephone. Without identifying interferon alfa as the treatment agent, interviewers described potential adverse effects, financial cost, and self-injection procedures. The potential benefits of four treatment choices, derived from a meta-analysis of published data, were presented as gains in remission rate (+10%), remission duration (an additional 4 and 7 months, respectively, for induction and maintenance treatment), and overall survival (an additional 3 and 6 months, respectively, for induction and maintenance treatment). Patients' choices for or against use of the unidentified substance were recorded, and interferon was subsequently disclosed as the treatment. The profiles of patients making different choices were determined using multivariate regression techniques.

RESULTS

Approximately half of the patients accepted the unidentified treatment if remission and/or survival improved by at least 6 months. Accepters were younger and more likely to have used interferon. Of patients who rejected the unidentified treatment, 25% to 50% would have been willing to accept it if the benefits were > or = 12 months. Test/retest reliability of all choices, determined in 36 cancer patients, was 0.896.

CONCLUSION

In multiple myeloma, interferon therapy and, by inference, other treatments with comparable features are acceptable to approximately half of the patients if a 6-month gain in relapse-free or overall survival can be expected.

Immunohistochemical evaluation of cathepsin D expression in colorectal cancer

Determination of cathepsin D has been proven to be prognostically relevant in breast cancer. Cathepsin D, a lysosomal proteinase, is suggested to be causally involved in tumor invasion. In this study we investigated cathepsin D expression immunohistochemically in 106 colorectal adenocarcinomas with the intention to evaluate its prognostic significance in this type of cancer. The majority of colorectal adenocarcinomas (93/106) stained positive for cathepsin D, while normal colon was almost completely negative. A trend toward stronger staining intensity was found in Dukes' stage C and D tumors (p < 0.1), but cathepsin D expression was found to have no influence on survival in this tumor type nor did it correlate with other known prognostic factors, e.g., histological differentiation, lymph vessel invasion, or rate of proliferation. Staining of lymph node metastases did not differ significantly from that of their primary tumors. Stronger staining intensity of tumor tissue in the neighborhood of inflammatory cells may be due to paracrine activation.

Maximal androgen blockade in combination with methotrexate for treatment of metastatic prostate cancer

Recently attention has been focused on the optimal timing of chemotherapy within the treatment regimen for patients with metastatic prostate cancer, i.e., hormonal manipulation, preferably maximal androgen blockage (MAB) consisting of chemical/surgical castration followed by treatment with antiandrogens. We have conducted a randomized prospective clinical trial, investigating the efficacy and toxicity of MAB (orchiectomy followed by flutamide therapy) alone as compared to MAB combined with methotrexate (MTX, 50 mg/m2/week) in 53 patients with newly diagnosed stage IV(M1) prostatic cancer (UICC TNM Classification 1987). The observed remission rates (complete + partial) of 42.3% in the MAB + MTX arm and 29.6% in the MAB arm did not differ significantly. The response rates (complete + partial + stable disease) of 73.1% and 66.7% for MAB + MTX and MAB respectively, also showed no significant difference. Neither progression-free survival (median 18/5 and 23.8 months for MAB + MTX and MAB, respectively) nor overall survival (median: 37.4 and 36.1) months in the MAB + MTX and MAB arm, respectively) could be improved by the addition of MTX to MAB Only the extent of metastatic pain reported by the patients was consistently less under MAB + MTX than under MAB alone (P<0.1). Both treatment regimens were well- tolerated with slightly more undesirable effects in the MAB + MTX arm. Our results do not provide evidence for the achievement of marked gains by combining chemotherapy with endocrine therapy in newly diagnosed patients with stage IV (M1) prostate cancer.

Recombinant human erythropoietin for the correction of cancer associated anemia with and without concomitant cytotoxic chemotherapy

BACKGROUND

Chronic anemia is a common complication in patients with cancer, especially in those with advanced disease or who are under intensive chemotherapy. Because homologous blood transfusions involve some hazards, the safety and efficacy of recombinant human erythropoietin (r-HuEPO) in the treatment of anemic patients with cancer with and without concomitant chemotherapy were studied.

METHODS

One-hundred two cancer patients with hemoglobin less than 11 g/dl, ferritin greater than 30 micrograms/l, and creatinine < 220 mumol/l were enrolled in the study, 94 were eligible for efficacy evaluation. Sixty-eight patients received chemotherapy (CT group) and 26 had no cytotoxic cancer treatment (NT group). Recombinant human erythropoietin was administered subcutaneously at a dose of 150 U/kg three times per week for 6 weeks; in nonresponders the dose was doubled for the subsequent 6 weeks. Response was defined as the achievement of a hemoglobin increase of 2g/dl. Clinical and laboratory parameters, including serum erythropoietin (EPO) levels, performance status, and quality of life, were investigated at baseline and monitored at regular intervals thereafter.

RESULTS

Response was achieved by 52% and 62% of CT and NT patients, respectively. The highest response rates were observed in patients with lung cancer or with a histology of squamous cell carcinoma (both 80%). In responding patients, the symptoms of anemia subsided. They no longer needed blood transfusions after 4 weeks of therapy; and both their performance status and quality of life improved significantly. The NT patients achieved slightly more favorable results on lower weekly doses: 450 U/kg/week in NT versus 570 U/kg/week in CT patients. Serum EPO levels were higher in nonresponders at baseline and further increased during the course of treatment. Recombinant human erythropoietin was well tolerated by all patients.

CONCLUSION

This multicenter study in a large patient collective shows that r-HuEPO treatment represents a safe and effective means to increase the red cell mass and eliminate the need for blood transfusions in approximately 50% of the patients with chronic anemia of cancer. Responding patients not only have increased levels of hemoglobin, but their performance status also improves significantly, and they enjoy a significantly enhanced quality of life.

Quantification of Coxiella burnetii by polymerase chain reaction (PCR) and a colorimetric microtiter plate hybridization assay (CMHA)

A colorimetric microtiter plate hybridization assay (CMHA) for the quantitative determination of Coxiella burnetii DNA after amplification by externally controlled polymerase chain reaction (PCR) is described. The quantification assay is based on an enzyme linked immunosorbent assay (ELISA) format. Cloned DNA, representing a sequence complementary to an internal part of the diagnostic amplicon, was noncovalently attached to the wells of a microtiter plate. Biotinylated PCR product was hybridized to the immobilized capture probe. Bound product was detected via streptavidin horse-radish peroxidase. The devised nonisotopic technique allows specific, rapid, and convenient quantification of C. burnetii DNA. Additionally, it is compatible with standard laboratory ELISA equipment, making this assay amenable to automation and permitting processing of large sample numbers.