Articulating the "stem cell niche" paradigm through the lens of non-model aquatic invertebrates.

Stem cells (SCs) in vertebrates typically reside in "stem cell niches" (SCNs), morphologically restricted tissue microenvironments that are important for SC survival and proliferation. SCNs are broadly defined by properties including physical location, but in contrast to vertebrates and other "model" organisms, aquatic invertebrate SCs do not have clearly documented niche outlines or properties. Life strategies such as regeneration or asexual reproduction may have conditioned the niche architectural variability in aquatic or marine animal groups. By both establishing the invertebrates SCNs as independent types, yet allowing inclusiveness among them, the comparative analysis will allow the future functional characterization of SCNs.

Cnidarian Primary Cell Culture as a Tool to Investigate the Effect of Thermal Stress at Cellular Level.

In the context of global change, symbiotic cnidarians are largely affected by seawater temperature elevation leading to symbiosis breakdown. This process, also called bleaching, is triggered by the dysfunction of the symbiont photosystems causing an oxidative stress and cell death to both symbiont and host cells. In our study, we wanted to elucidate the intrinsic capacity of isolated animal cells to deal with thermal stress in the absence of symbiont. In that aim, we have characterized an animal primary cell culture form regenerating tentacles of the temperate sea anemone Anemonia viridis. We first compared the potential of whole tissue tentacle or separated epidermal or gastrodermal monolayers as tissue sources to settle animal cell cultures. Interestingly, only isolated cells extracted from whole tentacles allowed establishing a viable and proliferative primary cell culture throughout 31 days. The analysis of the expression of tissue-specific and pluripotency markers defined cultivated cells as differentiated cells with gastrodermal origin. The characterization of the animal primary cell culture allowed us to submit the obtained gastrodermal cells to hyperthermal stress (+ 5 and + 8 °C) during 1 and 7 days. Though cell viability was not affected at both hyperthermal stress conditions, cell growth drastically decreased. In addition, only a + 8 °C hyperthermia induced a transient increase of antioxidant defences at 1 day but no ubiquitin or carbonylation protein damages. These results demonstrated an intrinsic resistance of cnidarian gastrodermal cells to hyperthermal stress and then confirmed the role of symbionts in the hyperthermia sensitivity leading to bleaching.

Ventralization of an indirect developing hemichordate by NiCl2 suggests a conserved mechanism of dorso-ventral (D/V) patterning in Ambulacraria (hemichordates and echinoderms).

One of the earliest steps in embryonic development is the establishment of the future body axes. Morphological and molecular data place the Ambulacraria (echinoderms and hemichordates) within the Deuterostomia and as the sister taxon to chordates. Extensive work over the last decades in echinoid (sea urchins) echinoderms has led to the characterization of gene regulatory networks underlying germ layer specification and axis formation during embryogenesis. However, with the exception of recent studies from a direct developing hemichordate (Saccoglossus kowalevskii), very little is known about the molecular mechanism underlying early hemichordate development. Unlike echinoids, indirect developing hemichordates retain the larval body axes and major larval tissues after metamorphosis into the adult worm. In order to gain insight into dorso-ventral (D/V) patterning, we used nickel chloride (NiCl2), a potent ventralizing agent on echinoderm embryos, on the indirect developing enteropneust hemichordate, Ptychodera flava. Our present study shows that NiCl2 disrupts the D/V axis and induces formation of a circumferential mouth when treated before the onset of gastrulation. Molecular analysis, using newly isolated tissue-specific markers, shows that the ventral ectoderm is expanded at expense of dorsal ectoderm in treated embryos, but has little effect on germ layer or anterior-posterior markers. The resulting ventralized phenotype, the effective dose, and the NiCl2 sensitive response period of Ptychodera flava, is very similar to the effects of nickel on embryonic development described in larval echinoderms. These strong similarities allow one to speculate that a NiCl2 sensitive pathway involved in dorso-ventral patterning may be shared between echinoderms, hemichordates and a putative ambulacrarian ancestor. Furthermore, nickel treatments ventralize the direct developing hemichordate, S. kowalevskii indicating that a common pathway patterns both larval and adult body plans of the ambulacrarian ancestor and provides insight in to the origin of the chordate body plan.

[External beam irradiation of head and neck cancer]. / Perkutane Strahlentherapie maligner Tumore im Kopf-Hals-Bereich.

Ionising rays are employed in percutaneous radiation of head and neck tumours. Radiation reduces cell division in the target tissue. The individual parameters of the radiation procedure are determined within the framework of the interdisciplinarily conceived treatment. Tumour control probability depends on tumour-specific factors and on the dosage as well as on the treatment period. The macroscopic and microscopic extend of the tumour area determines the target volume and dosage of the radiation. Conformal radiation is the standard procedure in primary radiation treatment. The anticipated side effects influence the therapy concept and the radiation parameters. Long-term aftercare of the tumour patient is imperative.

Guidelines for the infrastructure of training institutes and teaching departments for radiotherapy in Europe.

AIM: To develop guidelines for the infrastructure of training institutes and teaching departments for medical specialist training in radiotherapy within Europe. MATERIAL AND METHODS: Guidelines for teaching departments were developed under consideration of the updated European Core Curriculum for Radiotherapists (Radiation Oncologists) by an expert panel jointly appointed by the European Union of Medical Specialists and the European Society of Therapeutic Radiology and Oncology. The group approached national professional and scientific societies for information on national requirements for teaching departments. Based on this information, a draft document was circulated among the national and professional societies for radiotherapy in Europe for review before a European consensus conference took place in Brussels in December 2002. RESULTS: The guidelines for the infrastructure of training institutes and teaching departments for medical specialist training in radiotherapy within Europe were endorsed by representatives of 35 European nations during the Brussels consensus conference on December 14, 2002. CONCLUSION: The infrastructure guidelines represent an important instrument that can be used by teaching departments for comparison of their situation with that of other departments in Europe as a basis for negotiations with authorities on resources provided for training.

Evidence for radiosensitizing by gliotoxin in HL-60 cells: implications for a role of NF-kappaB independent mechanisms.

Radioresistance markedly impairs the efficacy of tumor radiotherapy and may involve antiapoptotic signal transduction pathways that prevent radiation-induced cell death. A common cellular response to genotoxic stress induced by radiation is the activation of the nuclear factor kappa B (NF-kappaB). NF-kappaB activation in turn can lead to an inhibition of radiation-induced apoptotic cell death. Thus, inhibition of NF-kappaB activation is commonly regarded as an important strategy to abolish radioresistance. Among other compounds, the fungal metabolite gliotoxin (GT) has been reported to be a highly selective inhibitor of NF-kappaB activation. Indeed, low doses of GT were sufficient to significantly enhance radiation-induced apoptosis in HL-60 cells. However, this effect turned out to be largely independent of NF-kappaB activation since radiation of HL-60 cells with clinically relevant doses of radiation induced only a marginal increase in NF-kappaB activity, and selective inhibition of NF-kappaB by SN50 did not result in a marked enhancement of GT-induced apoptosis. GT induced activation of JNKs, cytochrome c release from the mitochondria and potently stimulated the caspase cascade inducing cleavage of caspases -9, -8, -7 and -3. Furthermore, cleavage of the antiapoptotic protein X-linked IAP and downregulation of the G2/M-specific IAP-family member survivin were observed during GT-induced apoptosis. Finally, the radiation-induced G2/M arrest was markedly reduced in GT-treated cells most likely due to the rapid induction of apoptosis. Our data demonstrate that various other pathways apart from the NF-kappaB signaling complex can sensitize tumor cells to radiation and propose a novel mechanism for radiosensitization by GT, the interference with the G2/M checkpoint that is important for repair of radiation-induced DNA damage in p53-deficient tumor cells.

[Prostatectomy, brachytherapy, percutaneous irradiation. Which method helps your patients the most?]. / Prostatektomie, Brachytherapie, perkutane Bestrahlung. Welches Verfahren hilft Ihrem Patienten am besten?

For the treatment of cancer of the prostate that has not yet metastasized, several therapeutic options that promise lasting local tumour control are now available: Among the surgical options, radical retropubic prostatectomy is most commonly employed. The basic radiotherapeutic options are interstitial and external beam irradiation, or a combination of the two. The choice of the most suitable therapeutic approach is determined by the extent of the tumor, and the side effects that are acceptable to the patient.

Cell cycle and growth response of CHO cells to X-irradiation: threshold-free repair at low doses.

PURPOSE: To test the hypothesis of a threshold for induced repair of DNA damage (IR) and, secondarily, of hyperradiosensitivity (HRS) to low-dose X-irradiation. METHODS AND MATERIALS: Exponentially growing Chinese hamster ovary cells (CHO) were X-irradiated with doses from 0.2 to 8 Gy. Survival data were established by conventional colony-forming assay and flow-cytometric population counting. The early cell cycle response to radiation was studied based on DNA-profiles and bromodeoxyuridine pulse-labeling experiments. RESULTS: Colony-forming data were consistent with HRS. However, these data were of low statistic significance. Population counting provided highly reproducible survival curves that were in perfect accord with the linear-quadratic (LQ) model. The dominant cell cycle reaction was a dose-dependent delay of G2 M and late S-phase. CONCLUSION: There was no evidence for a threshold of IR and for low-dose HRS in X-irradiated CHO cells. It is suggested that DNA damage repair activity is constitutively expressed during S-phase and is additionally induced in a dose-dependent and threshold-free manner in late S-phase and G2. The resulting survival is precisely described by the LQ model.

Surgery, radio- and chemotherapy for multimodal treatment of rectal cancer.

The possibilities and results of multimodal treatment in rectal cancer were reviewed with respect to the results of surgical treatment only. Based on the results of 4 studies, reducing local relapse rates and increasing long term survival rates significantly, postoperative radiochemotherapy (RCT) + chemotherapy (CT) should remain the recommended standard for R0 resected UICC II and III rectal cancers. The addition of RT to adjuvant CT reduces local relapses without significant impact on survival (NSABP R-02). Vice versa, the addition of CT to RT or an improved CT in the RCT-concept prolongs survival. Preoperative neoadjuvant radiotherapy (RT) reduced local relapse rates in 9 studies, and extended survival in one study that evaluated all eligible patients. Preoperative RT reduced local relapse rates in addition to total mesorectal excision (TME) but did not extend survival. The preoperative RCT + CT downstages resectable and nonresectable tumors and induces a higher sphincter preservation rate. Phase III data justifying its routine use in all UICC II + III stages are not yet available. This treatment may be routinely applied in nonresectable primary tumors or local relapses. Preoperative RCT (or RT) may evolve as standard, if the patient selection is improved and postoperative morbidity and long term toxicity reduced. Intraoperative RT could be added to this concept or be used together with preoperative/postoperative RT at the same indications. Postoperative adjuvant RT reduced local relapses significantly in a single trial, and no impact on survival time is reported. Since postoperative RT is inferior to preoperative RT, this treatment cannot be recommended, if RT is chosen as a single treatment modality in adjunction to surgery. The results of local tumor excisions may be improved with pre- or postoperative RCT + CT. In the future, multimodal treatment of rectal cancer might be more effective, if individualized according to prognostic factors.

Radiation treatment related factors influencing outcome in vulvar cancer patients.

The objective of this research is to identify the impact of radiation treatment factors on survival in vulvar cancer patients. We performed a follow-up study on 60 women with squamous cell carcinoma of the vulva treated at the Department of Radiotherapy of the University of Ulm from 1980 to 1997. The follow-up time ranged from 0.5 to 17 years (mean 6.5 years). The irradiated volume included vulva and regional lymph nodes. The influence of treatment factors (tumor resection versus no tumor resection, treatment time, dose) on overall and disease-free survival was examined. In addition, applied doses were corrected for treatment time using the extended alpha/beta-model for calculating the biologically effective doses. The applied dose was 48.1 +/- 13.2 Gy (median: 50 Gy). Treatment time was 40.4 +/- 19.4 days (median: 38 days). 34/60 patients underwent surgery with complete resection of macroscopic tumor. 26 of 60 patients were resected incompletely or only a biopsy was taken. In univariate analysis prognostic factors influencing overall and disease-free survival were, along with T- and N-stage, treatment time, and biologically effective dose. In multivariate analysis, biologically effective dose was the only significant factor. We conclude that biologically effective dose and treatment time are important treatment factors influencing overall and disease-free survival vulvar cancer patients.

Comparative analysis of apoptosis in HL60 detected by annexin-V and fluorescein-diacetate.

BACKGROUND: Our aim was to compare and evaluate apoptosis formation as detected by propidium-iodide (PI)/annexin-V or PI/fluorescein-diacetate (FDA) as dose-response parameters in a human promyelocytic leukemia cell line, HL60. METHODS: In exponentially growing HL60 cells, apoptosis was induced by ionizing radiation, hyperthermia, topotecan, and cytosine beta-D-arabinofuranoside. At 4 consecutive days following induction, apoptosis was detected by double-labelling, either with PI/annexin-V or PI/FDA. Forward and side scatter, red (PI), and green (FDA or annexin-V) fluorescence were measured by flow cytometry. RESULTS: While light scatter discriminated between morphologically damaged and undamaged cells, fluorescence differentiated vital, apoptotic, and dead cells. Equal proportions of these three subpopulations were detected by both staining techniques. Occasionally, early and mature apoptoses were identified as distinct clusters. During the 4-day observation period, no pronounced maxima of the apoptotic fractions were obtained with either treatment modality. The gradual increases usually showed a delay of 1-2 days. CONCLUSIONS: FDA and annexin-V are equally suitable for detecting apoptosis. Separation improves with time after induction, indicating that, with respect to test specificity, mature apoptoses are superior to early stages. However, the sensitivity towards low rates of apoptosis after weak induction appears limited with both staining procedures.

[Effect of therapy on survival of patients with pancreatic carcinoma]. / Der Einfluss der Therapie auf das Uberleben von Patienten mit Pankreaskarzinom. Eine Analyse von Einzelfaktoren.

PURPOSE: To identify the impact of treatment factors on overall survival in patients with pancreatic carcinoma. PATIENTS AND METHODS: We performed a follow-up study on 38 patients with adenocarcinoma of the pancreas treated from 1984 to 1998. 18/38 patients were resected. Irradiated volume included the primary tumor (or tumor bed) and regional lymph nodes. Thirty-seven patients received in addition chemotherapy consisting of mitoxantrone, 5-fluorouracil and cis-platin, either i.v. (14/38) or i.a. (23/38). The influence of treatment related factors on the overall survival was tested. Biologically effective dose was calculated by the linear-quadratic model (alpha/beta = 25 Gy) and by losing 0.85 Gy per day starting accelerated repopulation at day 28. RESULTS: Treatment factors influencing overall survival were resection (p = 0.02), overall treatment time (p = 0.03) and biologically effective dose (p < 0.002). Total dose and kind of chemotherapy had no significant influence. Treatment volume had a negative correlation (r = -0.5, p = 0.06) with overall survival, without any correlation between tumor size, tumor stage, and treatment volume. In multivariate analysis only biologically effective dose remained significant (p = 0.02). CONCLUSIONS: Among with surgery, biologically effective dose strongly influences overall survival in patients treated for pancreatic carcinoma. Treatment volume should be kept as small as possible and all efforts should be made to avoid treatment splits in radiation therapy.

Differential proliferation dependence of alpha and beta damage in X-irradiated Chinese hamster cells.

PURPOSE: To determine quantitatively the influence of altering proliferation rates on clonal survival of asynchronously growing Chinese hamster (CHO) cells after X-irradiation and to evaluate the related contribution of alpha and beta damage. MATERIAL AND METHODS: Cell cycle distributions at the time of X-irradiation of CHO cells were assessed by flow cytometry. Clonal radiation survival was established by colony forming assay. Survival data were fitted to the linear-quadratic model and analyzed on the basis of the mean inactivation dose, D. RESULTS: Increased S-phases were associated with increased resistance to X-rays. Radiosensitivity as expressed by D differed by a factor of 1.6 between the most sensitive and the most resistant populations. Separately analyzing the alpha and beta coefficients of survival curves revealed that the proliferation dependent effect was correlated only with beta. The major determinant of D was alpha, but its substantial interexperimental variations were independent of the cell cycle. CONCLUSIONS: Due to altering cell cycle distributions, considerable changes of radiosensitivity can occur. They can in part be understood as a consequence of S-phase dependent alterations of DNA damage repair. Reasons for the changes of a damage dependent lethality remain to be discovered by further research.

[Radiotherapy for tumor pain. Long-term freedom from pain with minimal side-effects]. / Strahlen gegen Tumorschmerzen. Langanhaltende Schmerzfreiheit bei geringen Nebenwirkungen.

Radiotherapy may be the treatment of choice in patients suffering pain from early-stage cancer and is used in curative intent. In addition, it is often used for palliative treatment in advanced tumor disease, when, thanks to local regression of the tumor, pain relief may be long-term and achieved with only mild or moderate side effects.

20 MHz ultrasonic imaging for quantitative assessment and documentation of early and late postradiation skin reactions in breast cancer patients.

BACKGROUND AND PURPOSE: In dermatology high resolution ultrasonic systems proved to be valuable in following up genuine and experimental inflammatory dermatoses. The opportunities of 20 MHz ultrasonic imaging for quantitative assessment of early and late postradiation skin reactions are investigated. MATERIAL AND METHODS: Between April and November 1996, 96 high resolution ultrasound examinations of the skin in 29 patients treated for breast cancer at the University of Ulm were analyzed. Total doses between 46 and 60 Gy were applied. The time interval between the completion of radiotherapy and ultrasonic examination was < or =3 months in 18 patients and 6-135 months in 11 patients. For examinations we used a digital high resolution ultrasonic system with a ceramic 20 MHz transducer. Irradiated and non-irradiated skin were compared. RESULTS: A change of thickness and texture of the dermis depending on the time interval between the completion of radiotherapy and ultrasonic examination and on the administered radiation dose was found. There were significant differences between irradiated and non-irradiated skin regarding the dermal thickness in early (P < 0.001) as well as in late (P = 0.0018) reactions. Echogenicity of the upper and lower corium of irradiated skin decreased in early and late reaction. In upper corium the greatest reduction of signal intensity occurred in early reactions (P = 0.0001). Early reactions of the lower corium differed significantly from late changes (P = 0.001). Discrepancies between visible skin reactions described by examining physicians and ultrasonically proven changes were obvious mainly in late reactions. CONCLUSIONS: There are specific textures of early and late postradiation skin reactions in comparison to non-irradiated skin. High resolution digital 20 MHz ultrasound is non-invasive and quantitative, and in contrast to physical examination, an easy reproducible method for assessing and documenting early and late skin reaction during and after radiation therapy treatment.

Adjuvant radiochemotherapy--what is the patients benefit?

BACKGROUND: Local relapse is a major problem after potentially curative rectal cancer surgery. Although the incidence of local recurrences may be reduced by specialized surgical techniques such as total mesorectal excision (TME), local relapse rates of 20% or higher are the surgical reality today. Studies using adjuvant postoperative radiotherapy, chemotherapy, radiochemotherapy or immunotherapy have tried to reduce local relapse rates and distant progression. Postoperative radiochemotherapy has been the recommended standard, after complete resection of Union Internationale Contra la Cancrum (UICC) stages II and III rectal cancers. In view of recent positive results with preoperative radiotherapy of TME without adjuvant therapy, we found it important to review the literature to update the recommendable adjuvant procedure in rectal cancer. METHOD/PATIENTS: The literature from 1985 to May 1998 was reviewed for studies trying to either confirm or improve adjuvant therapy in rectal cancer. Only randomized controlled trials were analyzed with regard to their effectiveness in reducing the absolute rates of local recurrence and improving survival. RESULTS: Two trials applying adjuvant radiotherapy were able to demonstrate the reduction of local relapse rates, one trial with marginal significance, both without impact on survival. Four trials involving 1104 patients with rectal cancer stages UICC II-III compared postoperative radiochemotherapy with either surgical controls, adjuvant radiotherapy or conventional radiochemotherapy. In these trials, local relapse rates were significantly reduced by 11-18%, and survival rates significantly improved by 10-14%. Severe acute toxicities occurred in 50-61% of the patients, compromising compatibility, and caused death in 0-1%. Small-bowel obstruction leading to surgery was noted in 2-6% and to death in up to 2% of the patients. Intraoperative radiotherapy (IORT) improved local control and survival after surgery of locally advanced disease/local relapse. CONCLUSION: In view of four trials demonstrating a significant benefit of postoperative radiochemotherapy and with regard to recent still-debatable results of preoperative short-term radiotherapy optimal surgery with lowest local relapse rates plus postoperative radiochemotherapy remains the actual recommendable standard for rectal cancer surgery in R0 resected tumors stages UICC II+III.

Multimodal therapy in rectal cancer.

The possibilities and results of multimodal treatment in rectal cancer were reviewed with respect to the results of surgical treatment only. Based on the results of 4 studies, reducing local relapse rates and increasing long-term survival rates significantly, postoperative radiochemotherapy (RCT) + chemotherapy (CT) should remain the recommended standard for R0 resected UICC II and III rectal cancers. Preoperative neoadjuvant radiotherapy (RT) reduced local relapse rates in 8 studies, and extended survival in one study that evaluated all eligible patients. Preoperative RT may evolve as standard, if the patient selection is improved and postoperative morbidity and long-term toxicity are reduced. Postoperative adjuvant RT reduced local relapses significantly in a single trial, and no impact on survival time is reported. Since postoperative RT is inferior to preoperative RT, this treatment cannot be recommended, if RT is chosen as a single treatment modality as an adjunct to surgery. Preoperative RCT + CT downstages resectable and nonresectable tumors and induces a higher sphincter preservation rate. This treatment may be routinely applied in nonresectable primary tumors or local relapses. Intraoperative RT could be added to this concept or be used together with preoperative/postoperative RT with the same indications. The results of local tumor excisions may be improved with pre- or postoperative RCT + CT.

Stable radiobiological features in a genetically unstable glioblastoma cell line.

In a human glioblastoma (grade IV) cell line, A7, the change in chromosome number, growth characteristics, radiosensitivity and DNA-repair capacity were determined during continuous culture over approximately 1300 generations. The median chromosome number fell from 101 to 85 while a remarkable variability was retained. The net population doubling time shortened from 21 to 16 h but no alterations were detected either in radiosensitivity or DNA-repair capacity, as measured by colony and plasmid-reconstitution assays respectively. Reviewing radiosensitivity data from the literature, it is considered that the relative radioresistance of glioblastomas might be inherited from the normal tissue from which they are derived.

Quality assurance by specification and achievement of goals in palliative cancer treatment.

As the goals of palliative cancer treatments have not always been clearly specified, this paper describes how frequently the goals of palliative cancer treatment can be specified according to a given definition and how frequently those specified goals can be achieved. The clinical problems of 171 cancer patients were discussed in the Interdisciplinary Oncologic Conference (IOC) of the Cancer Centre University of Ulm (CCUU) and recommendations concerning further diagnostic treatments and/or therapy were provided. These recommendations had been documented and analysed retrospectively. The goals were classified as either cure or palliation or further investigation. If the goal was palliation, it was investigated whether or not the goal was specified as either alleviation of existing problems or prevention of impending problems. The achievement of the specified goals was assessed. Palliation was the goal of treatment in 119 (71%) of the 168 evaluable recommendations. In 83 of the 119 cases (70%), immediate treatment was recommended. The goal was specified in 57 (69%) of the 83 recommendations and could be realized in 24 of 57 specified cases (42%). Patients in this group survived longer (p < 0.01) than patients in whom the goals could not be achieved. Impending problems could be prevented more often (p = 0.001) in 14 out of 18 cases, while existing problems could be alleviated in only 10 out of 34 cases. It is concluded that specification of the goals of palliation is necessary because it is impossible to decide if a goal of treatment could be achieved or not unless the goal of treatment has been defined (as existing/impending problem). The prevention of impending problems could be investigated in prospectively controlled clinical trials.