Development and characterisation of an irradiation device for biomedical studies covering the solar spectrum with individual regulated spectral bands

To understand the importance of terrestrial solar exposure on human skin, not only individual spectral components need to be considered in biomedical studies, but also the relevance of the combined action profile of the complete solar spectrum (cSS) must be established. We therefore developed a novel irradiation device that combines the emission of four individual lamps (UVB, UVA, VIS and nIR) to achieve exposure from 280 to 1400 nm with individual controllable lamps. The integrated irradiance of each spectral band is similar to the solar spectrum. The lamps can be utilised individually or in any desired combination. Here we present the design, realisation, and validation of this irradiation device as well as biological results on cellular metabolism (MTT assay), cell cycle alterations, and clonogenic growth in HaCaT cells after exposures to the individual spectral bands as well as their simultaneous combinations. Thereby, we demonstrate that UVB combined with UVA is the main determinant for the metabolic activity within cSS. Also, UVB-dependent effects dominate cell cycle regulation in cSS, whilst UVA and nIR have little influence. Lastly, also clonogenic growth is dominated by the UVB action profile in cSS, despite nIR showing modulatory activity when applied in combination with UVB. Together, this highlights the regulatory influence of the different spectral bands on the three biological endpoints and demonstrates their modulation when being part of the complete solar spectrum.

660 PHYSIOTHERAPISTS PERCEPTIONS OF MECHANISMS FOR OBSERVED VARIATION IN PRACTICE DURING EARLY POSTOPERATIVE PHASE AFTER HIP FRACTURE

Objective

To explore physiotherapists’ perceptions of mechanisms to explain observed variation in early postoperative practice after hip fracture surgery demonstrated in a national audit.

Methods

A qualitative semi-structured interview study of 21 physiotherapists working on orthopaedic wards at 7 hospitals with different durations of physiotherapy during a recent audit. Thematic analysis of interviews drawing on Normalisation Process Theory to aid interpretation of findings.

Results

Four themes were identified: achieving protocolised and personalised care; patient and carer engagement; multidisciplinary team engagement across the care continuum; and strategies for service improvement. Most expressed variation from protocol was legitimate when driven by what is deemed clinically appropriate for a given patient. This tailored approach was deemed essential to optimise patient and carer engagement. Participants reported inconsistent degrees of engagement from the multidisciplinary team attributing this to competing workload priorities, interpreting ‘postoperative physiotherapy’ as a single professional activity rather than a care delivery approach, plus lack of integration between hospital and community care. All participants recognised changes needed at both structural and process levels to improve their services.

Conclusion

Physiotherapists highlighted an inherent conflict between their intention to deliver protocolised care while allowing for an individual patient-tailored approach. This conflict has implications for how audit results should be interpreted, how future clinical guidelines are written, and how physiotherapists are trained. Physiotherapists also described additional factors explaining variation in practice which may be addressed through increased engagement of the multidisciplinary team and resources for additional staffing and advanced clinical roles.

659 PATIENT PERSPECTIVES OF RECOVERY AFTER HIP FRACTURE: A SYSTEMATIC REVIEW AND QUALITATIVE SYNTHESIS

Background

Recovery is multidimensional highlighted by a wealth of qualitative evidence published on patient perspectives of recovery after hip fracture. The purpose of the current review is to synthesize this evidence of patients’ perspectives of recovery after hip fracture across the care continuum.

Methods

A systematic search was conducted, focusing on qualitative data from hip fracture patients. Two authors independently screened title and abstracts, full texts, completed extraction, and quality appraisal. Themes for this review were generated using a thematic synthesis of data from original studies.

Results

Fourteen qualitative studies were included in this review. The overall quality of included studies was high. We identified four review themes: defining recovery, feelings of vulnerability, driving recovery, and reliance on support. Patients considered recovery as a return to prefracture activities or ‘normal’ enabling independence. Feelings of vulnerability were observed for patients irrespective of the time since hip fracture and only diminished when recovery of function and activities enabled participation in valued activities e.g. outdoor mobility. Participants expressed a desire to actively engage in recovery with realistic expectations and benefits of meaningful feedback reported. Reliance on healthcare support varied by time since fracture with patients highlighting a greater reliance on professional support in the early versus late stages of recovery. Reliance on social support persisted until recovery was perceived to have been achieved and was highlighted more for participants who were living alone.

Conclusion

Patient perspectives of recovery enhance previous understanding of recovery domains. Patient perspectives highlighted hip fracture as a major life event which requires health professional and social support to overcome feelings of vulnerability and enable active engagement in recovery. Future research should investigate the recovery perspective of patients with cognitive impairment, and further consider perspectives on recovery from carers.

Aktualisierung der S2k-Leitlinie zur Diagnostik, Therapie und Metaphylaxe der Urolithiasis (AWMF Registernummer 043-025)

Die Zunahme des medizinischen Wissens, technische Neuerungen gemeinsam mit demographischem Wandel stellen eine Herausforderung an die Neukonzeption von Leitlinien und klinischen Studien dar. Die vorliegende S2k-Leitlinie, die sich ausschließlich mit Nieren- und Harnleitersteinen beschäftigt, soll die Behandlung von Harnsteinpatienten in Klinik und Praxis unterstützen, aber auch Patienteninformationen zur Urolithiasis geben. Die zunehmende interdisziplinäre Zusammenarbeit in der Steintherapie zeigt sich auch an der Anzahl beteiligter Fachgruppen und Arbeitsgemeinschaften in der Erstellung des neuen Leitlinienupdates. Die vorliegende, aus einem interdisziplinären Konsensusprozess hervorgegangene S2k-Leitlinie stellt die aktuellen Empfehlungen praxisnah dar und gibt Entscheidungshilfen für Diagnostik‑, Therapie- und Metaphylaxemaßnahmen auf Basis von Expertenmeinungen und verfügbaren Evidenzgrundlagen aus der Literatur.

Interval cancers after skin cancer screening: incidence, tumour characteristics and risk factors for cutaneous melanoma

BACKGROUND

The rate of interval cancers is an established indicator for the performance of a cancer-screening programme.

METHODS

We examined the incidence, tumour characteristics and risk factors of melanoma interval cancers that occurred in participants of the SCREEN project, which was carried out 2003/2004 in Schleswig-Holstein, Germany. Data from 350 306 SCREEN participants, who had been screened negative for melanoma, were linked to data of the state cancer registry. Melanoma interval cancers were defined as melanomas diagnosed within 4-24 months after SCREEN examination. Results were compared with melanomas of the pre-SCREEN era (1999-2002), extracted from the cancer registry.

RESULTS

The overall relative incidence of melanoma interval cancers in terms of observed/expected ratio was 0.93 (95% CI: 0.82-1.05; in situ: 1.61 (1.32-1.95), invasive: 0.71 (0.60-0.84)). Compared with melanomas of the pre-SCREEN era, the interval melanomas were thinner and had a slightly greater proportion of lentigo maligna melanomas whereas nodular melanomas were less frequent.

INTERPRETATION

The results indicate a moderate performance of the SCREEN intervention with an excess of in situ melanomas. In part, the findings might be due to specifics of the SCREEN project, in particular a short-term follow-up of patients at high risk for melanoma.

Effectiveness of skin cancer screening programmes

Skin cancer, nonmelanoma skin cancer (NMSC) and cutaneous malignant melanoma (CMM), is the most frequent cancer worldwide. It is amenable to early detection, and screening for skin cancer has the potential to reduce mortality and morbidity. However, there are no recommendations for population-based skin cancer screening programmes due to the lack of evidence for the effectiveness from epidemiological studies. In 2008 the first nationwide screening programme for NMSC and CMM in the world was established in Germany. The decision for implementing such a programme was based on the results and evidence of a pilot study that was conducted from 2003 to 2004. The pilot study revealed that a population-based screening programme for skin cancer is feasible and effective. Careful evaluation of the nationwide programme is crucial to generate strong evidence for long-term public health benefits.

UVA-induced DNA double-strand breaks result from the repair of clustered oxidative DNA damages

UVA (320-400 nm) represents the main spectral component of solar UV radiation, induces pre-mutagenic DNA lesions and is classified as Class I carcinogen. Recently, discussion arose whether UVA induces DNA double-strand breaks (dsbs). Only few reports link the induction of dsbs to UVA exposure and the underlying mechanisms are poorly understood. Using the Comet-assay and γH2AX as markers for dsb formation, we demonstrate the dose-dependent dsb induction by UVA in G(1)-synchronized human keratinocytes (HaCaT) and primary human skin fibroblasts. The number of γH2AX foci increases when a UVA dose is applied in fractions (split dose), with a 2-h recovery period between fractions. The presence of the anti-oxidant Naringin reduces dsb formation significantly. Using an FPG-modified Comet-assay as well as warm and cold repair incubation, we show that dsbs arise partially during repair of bi-stranded, oxidative, clustered DNA lesions. We also demonstrate that on stretched chromatin fibres, 8-oxo-G and abasic sites occur in clusters. This suggests a replication-independent formation of UVA-induced dsbs through clustered single-strand breaks via locally generated reactive oxygen species. Since UVA is the main component of solar UV exposure and is used for artificial UV exposure, our results shine new light on the aetiology of skin cancer.

Skin cancer screening participation and impact on melanoma incidence in Germany--an observational study on incidence trends in regions with and without population-based screening

BACKGROUND

The SCREEN (Skin Cancer Research to provide Evidence for Effectiveness of Screening in Northern Germany) project involved population-wide skin cancer screening with whole-body examination by general physicians and dermatologists. It was conducted in the German state of Schleswig-Holstein (July 2003-June 2004), but not in the German state of Saarland.

METHODS

The population-based registries of Schleswig-Holstein and Saarland provided data on melanoma incidence before, during, and after SCREEN to assess the association of skin cancer screening with incidence.

RESULTS

Approximately 19% of the Schleswig-Holstein population participated in SCREEN (women: 27%, men: 10%). A total of 52% of all melanomas diagnosed during SCREEN in Schleswig-Holstein were detected as part of the project. Melanoma incidence increased during SCREEN (invasive melanoma in women: +8.9 per 100,000 (95% confidence intervals (CI): 6.1; 11.7); men: +4.0 per 100,000 (95% CI: 1.6; 6.4)) and decreased afterwards (women: -10.6 per 100,000 (95% CI: -13.3; -7.9); men: -4.1 per 100,000 (95% CI: -6.5; -1.7)). Similar changes were not observed in Saarland that had no such project. The differences between the two states were greatest among women, the group with the greater SCREEN participation.

CONCLUSION

The SCREEN project had a substantial impact on melanoma incidence. This is consistent with the impact of effective screening for other cancers.

[Representation of cystectomy and urinary diversion in the G-DRG system 2010: an example for the complexity of the reimbursement system]

Cystectomy and urinary diversion is an excellent example for the growing complexity of the G-DRG (German diagnosis-related groups) system. Based on different diagnoses (malignant tumor of the urinary tract, benign disease of the urinary tract, malignant tumor of the female genital tract, or malignant tumor of the male genital tract), identical cases may lead to very different codes, resulting in even more differences in reimbursement.

[Adjustment of the German DRG system in 2009]

BACKGROUND

The 2009 version of the German DRG system brought significant changes for urology concerning coding of diagnoses, medical procedures and the DRG structure. In view of the political situation and considerable economic pressure, a critical analysis of the 2009 German DRG system is warranted. Analysis of relevant diagnoses, medical procedures and G-DRGs in the versions 2008 and 2009 based on the publications of the German DRG-institute (InEK) and the German Institute of Medical Documentation and Information (DIMDI).

RESULTS

The relevant diagnoses, medical procedures and German DRGs in the versions 2008 and 2009 were analysed based on the publications of the German DRG Institute (InEK) and the German Institute of Medical Documentation and Information (DIMDI). Changes for 2009 focus on the development of the DRG structure, DRG validation and codes for medical procedures to be used for very complex cases. The outcome of these changes for German hospitals may vary depending in the range of activities.

CONCLUSION

The German DRG system again gained complexity. High demands are made on correct and complete coding of complex urology cases. The quality of case allocation in the German DRG system was improved. On the one hand some of the old problems (e.g. enterostomata) still persist, while on the other hand new problems evolved out of the attempt to improve the case allocation of highly complex and expensive cases. Time will tell whether the increase in highly specialized DRG with low case numbers will continue to endure and reach acceptable rates of annual fluctuations.

Ureterstriktur nach extrakorporaler Stoßwellenlithotripsie

Extracorporeal shock wave lithotripsy (ESWL) is considered a very safe and noninvasive procedure for the treatment of urolithiasis. Achievements in the technical development of recent decades resulted in a continuous reduction of side effects. One of our patients, a woman with cystinuria, developed a temporary ureteral stricture after several sessions of ESWL. Encouraged by this observation we set out to explore--based on a MEDLINE literature search--published reports of more severe side effects observed in modern ESWL therapy. Besides hydronephrosis and renal colic the most common side effects were renal and perirenal hematomas in up to 4% in the larger series. Uncommon extrarenal complications are described mostly in case reports, which are also outlined in this report. The injury of visceral organs (liver, spleen, gut, pancreas) was published most frequently. A rupture or dissection of an abdominal aortic aneurysm as an outstanding serious complication was also reported several times. Taking obvious and well-known contraindications into consideration and carefully preparing the patients for the therapy (i.e., checking hemostasis, drug history), ESWL is a very safe procedure with a low risk of serious complications. Yet, postoperative clinical and ultrasound monitoring seems to be essential especially with respect to the increasing numbers of outpatient procedures.

Der Einfluss des T-Stadiums auf das Metastasierungsrisiko des Peniskarzinoms: T1 vs. T2

BACKGROUND

Controversies persist over the therapeutic approach to T1 penile carcinoma, particularly in patients with negative inguinal lymph nodes. Available data on lymph nodes metastases (LNM) in T1 carcinoma are contradictory. The aim of this study was to evaluate the metastatic risk of T1 carcinoma and to compare it with that of T2 carcinoma.

MATERIAL AND METHODS

A total of 37 patients (pts) with T1 or T2 tumors were reviewed. Assessment of the inguinal lymph node condition was based on node dissection in 29 pts and surveillance in eight pts (mean 62 months, range 22-162).

RESULTS

Grading was classified as good (G1), moderate (G2) and poor (G3) in seven, 26 and four pts, respectively. Tumor stage was T1 in 21 and T2 in 16 pts. LNM were observed in eight of 21 T1 (38%) and six of 16 T2 tumors (38%). No G1 and all G3 tumors developed LNM independently of tumor stage. Ten of the 26 G2 carcinomas (38%) harboured LNM and seven of these pts (70%) had a T1 tumor.

CONCLUSIONS

According to our data, the metastatic potential of T1 penile carcinoma has been underestimated in the recent literature. Tumor grading has a substantially stronger impact on the metastatic risk in T1 and T2 penile carcinoma than tumor stage, indicating a surgical lymph node staging starting at the pT1G2 stage.

Effectiveness of information campaigns

Skin cancer represents the most common type of cancer in the white population worldwide and the incidence has dramatically increased during the last decades. UV-radiation is believed to be the most important risk factor responsible for this trend. The prominent role of UV-radiation renders skin cancer most suitable for primary prevention, because the main risk factor can easily be avoided by sticking to simple rules for the behaviour in the sun or under artificial UV (e.g. sunbeds). Since UV-exposure cannot and should not be avoided totally especially due to the beneficial health effects of UV-irradiation like Vitamin D(3)-production, recommendations and information for the public should be as clear and as weighted as possible, through adequate messages, such as: "Love the sun and protect your skin". For that purpose the Association of Dermatological Prevention in Germany (ADP) developed the period of life programme (POLP) that defines certain age-specific target groups, with the aim to give well adapted prevention messages to the population during lifetime. Evaluation of primary prevention campaigns in Germany showed that due to continuous intervention programs during the last 16 years changes in the "sun-behaviour" of the population have been achieved leading to a reduced but sufficient exposure to solar UV-irradiation. This will then contribute to the aim of decreasing morbidity and mortality of skin cancer.

Strukturierte Qualitätsberichte urologischer Hauptabteilungen gemäß § 137 SGB V

In 2005, German hospitals were legally obliged to publish a structured quality report on their data of 2004 including the top 10 diagnosis-related groups, top 10 diagnoses, and top 10 procedures for every specialty. The aim was to increase the transparency for patients, doctors, and health insurance companies. Comparing the quality reports of 248 departments of urology revealed very uniform distributions of diagnoses and diagnosis-related groups. There was a large variety of top 10 procedures, resulting from different interpretations of the coding system, leading to diminished accuracy. The quality reports provide coding specialists with important data, but for patients and nonspecialized doctors, this system is not helpful in improving transparency.

Pr�vention von Hautkrebs

Including malignant melanoma, basal cell carcinoma, and squamous cell carcinoma, skin cancer is the cancer with the highest incidence worldwide. Its incidence is increasing more rapidly than that of all other kinds of cancer. It is necessary to slow down this trend through preventive steps in order to reduce morbidity and mortality rates and to decrease the financial burden on the health systems. This goal could be achieved through primary (prevention of risk factors) and secondary prevention (early diagnosis and screening). This essay describes the necessity, realization, and success of these kinds of intervention programs. It especially portrays the procedures in Germany as they have been practiced for the last 15 years by the Society of Dermatology Prevention and German Cancer Aid.

Chemotherapie des Harnblasenkarzinoms

For many years, MVAC chemotherapy has been the standard treatment for patients with advanced bladder cancer. Since only a small proportion of patients with advanced disease may be cured by chemotherapy, the expected toxicity profile has to be balanced against the clinical benefit. It is of importance to select patients who may probably respond to chemotherapy. The treatment-associated toxicity needs to be considered especially in unfit and elderly patients. The introduction of innovative new compounds and combinations for the treatment of advanced bladder cancer has opened new avenues. In particular, the good activity of the synthetic nucleoside analogue gemcitabine has improved chemotherapeutic approaches for older patients. For this group of patients, monotherapy with gemcitabine or paclitaxel as well as combinations with cisplatin, carboplatin, or methotrexate is feasible with acceptable side effects.

[Complications of transrectal prostate biopsy. Determination of current status]

The procedure for prostate biopsy has undergone a dramatic change in the last 2 decades. The introduction of PSA into diagnostics for prostate carcinoma and simultaneous development of modern biopsy techniques have led to a marked increase in transrectal prostate biopsies. At the same time, serious complications have become less frequent. Grave complications after biopsy include septic complications (approximately 1%), rectal hemorrhages (approximately 0.1%), and ischurias (0.5%). Less severe complications such as occurrence of fever without septic signs account for 3.5%. One of the frequent complications that usually do not require treatment is gross hematuria, which is observed in nearly 50% of all patients. The same applies to hematospermia with a similar frequency.In the rare cases of the altogether serious complications after prostate biopsy, appropriate action is essential. All in all, prostate biopsy nowadays represents a safe diagnostic procedure with few complications and an extraordinarily high level of usefulness for everyday urological practice.

Identification of a non-dividing subpopulation of mouse and human epidermal cells exhibiting high levels of persistent ultraviolet photodamage

The distribution and persistence of cyclobutane pyrimidine dimers were investigated in mouse skin after chronic and acute exposures to ultraviolet-B radiation. We found that DNA damage accumulated in response to chronic irradiation and persisted in a unique set of epidermal cells located at the basal layer. Treatment with a tumor promoter caused the heavily damaged epidermal cells to divide and p53-immunopositive clusters to form within 24 h suggesting that these cells may be progenitors of the mutant p53 clusters associated with actinic keratoses and squamous cell carcinomas. In contrast to low fluence chronic irradiation, daily treatment with a higher fluence of ultraviolet-B produced extensive hyperplasia and considerably reduced penetration of photodamage. Exposure of chronically irradiated skin to an acute "sunburn dose" of ultraviolet-B also produced significant epidermal hyperplasia and resulted in complete loss of heavily damaged basal cells within 4 d postirradiation. The occurrence and distribution of cyclobutane dimers in human skin correlated well with putative sunlight exposure and resembled that observed in ultraviolet-B-irradiated mice. Heavily damaged basal cells were observed at various sites, including those receiving sporadic sunlight exposure, suggesting that these cells may play an important role in carcinoma formation in humans.

New-generation lithotripters for treatment of patients with implantable cardioverter defibrillator: experimental approach and review of literature

PURPOSE

The influence of shockwaves applied during extracorporeal shockwave lithotripsy on the function of implantable cardioverter defibrillators was evaluated. Mechanical influences as well as proper electrical function were tested in an experimental approach.

MATERIALS AND METHODS

Two implantable defibrillators (Ventak Mini 1743 and AVII 1821) were exposed to the shockwaves of a new-generation lithotripter. Each of the antidysrhythmic devices was tested at several distances from and within the focus of the lithotripter. All studies were performed with maximum energy and the number of shockwaves used for stone treatment. The devices were connected to an ECG simulator, and continuous recording of a surface ECG, a shock ECG, and marker channel was performed.

RESULTS

No macroscopic and microscopic mechanical damage was observed. The detection function of the implantable defibrillators was not altered by any electromagnetic artifacts even when brought into the focus of the shockwaves. All induced ventricular dysrhythmias were terminated properly regarding artifact sensing. However, after defibrillation, the pacing function of the Ventak Mini cardioverter defibrillator, which was programmed into the demand mode, failed. In this case, there was no post-shock pacing in the period of post-defibrillation asystole. The failure was caused by artifact oversensing.

CONCLUSION

In patients with implanted cardiac devices undergoing treatment with a new-generation lithotripter, deactivation of the defibrillator is not mandatory. For safety reasons, continuous ECG recording is recommended. To avoid pacing failure by artifact oversensing, the shockwaves should be applied in a R-wave synchronous mode.

The dose dependence of cyclobutane dimer induction and repair in UVB-irradiated human keratinocytes

UVB and UVA components of the solar spectrum or from artificial UV-sources might be important etiological factors for the induction and development of skin cancer. In particular, deficiencies in the capacity to repair UV-induced DNA-lesions have been linked to this phenomenon. However, until now only limited data are available on the biological and physical parameters governing repair capacity. We have, therefore, developed a flowcytometric assay using fluorescence-labeled monoclonal antibodies to study the dose-dependence of induction and repair of UVB-induced cyclobutane pyrimidine dimers in a spontaneously immortalized keratinocytic cell line (HaCaT). Our results show that the kinetics of recognition and incision of UVB-induced DNA lesions slows down by a factor of about 3 in a dose range of 100-800 J m-2. Furthermore, a thorough analysis of repair kinetics indicates that this reduction in repair capacity might not be dependent on saturation of enzymatic repair capacity (Michaelis-Menten) but may be caused by a UV-induced impairment of enzymes involved in DNA repair. Because this effect is evident in vitro at doses comparable to the minimal erythemal dose in vivo, our results might have significant impact on risk assessment for UV-induced carcinogenesis.

Experience with carbon-11 choline positron emission tomography in prostate carcinoma

We investigated the potential of carbon-11 choline positron emission tomography (PET) for the detection of lymph node and bone metastases in prostate cancer. A total of 23 patients were studied (known metastases: 8; suspicion of metastases: 3; primary staging: 12). Whole-body PET imaging was performed 5 min after injection of the tracer and completed within 1 h. Focally increased tracer uptake in bone or abdominal lymph node regions was interpreted as representing tumour involvement. All known bone and lymph node metastases could be recognized by [11C]choline PET. One out of ten negative scans for primary staging was false-negative (lymph node <1 cm) and one out of two positive scans was false-positive with regard to lymph node involvement (focal bowel activity). It is concluded that [11C]choline PET is a promising new tool for the primary staging of prostate cancer, with lymph node and bone metastases demonstrating high tracer uptake. Therapeutic management could be influenced by these results in that the technique may permit avoidance of surgical lymph node exploration.

Effects of chronic low-dose ultraviolet B radiation on DNA damage and repair in mouse skin

Chronic exposure to sunlight causes skin cancer in humans, yet little is known about how habitual exposure to low doses of ultraviolet B radiation (UVB) affects DNA damage in the skin. We treated Skh-1 hairless mice with daily doses of suberythemal UVB for 40 days and analyzed the amount and distribution of DNA photodamage using RIAs and immunofluorescence micrography. We found that DNA damage accumulated in mouse skin as a result of chronic irradiation and that this damage persisted in the dermis and epidermis for several weeks after the chronic treatment was terminated. Although the persistent damage was evenly distributed throughout the dermis, it remained in the epidermis as a small number of heavily damaged cells at the dermal-epidermal boundary. Rates of DNA damage induction and repair were determined at different times over the course of chronic treatment in response to a higher challenge dose of UVB light. The amount of damage induced by the challenge dose increased in response to chronic exposure, and excision repair of cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone dimers was significantly reduced. The sensitization of mouse epidermal DNA to photoproduct induction, the reduction in excision repair, and the accumulation of nonrepairable DNA damage in the dermis and epidermis suggest that chronic low-dose exposure to sunlight may significantly enhance the predisposition of mammalian skin to sunlight-induced carcinogenesis.

[3D endosonography to clarify distal ureteral processes]

PURPOSE

Evaluation of 3D endoluminal sonography as a diagnostic modality in lower ureteral pathologies.

MATERIALS AND METHODS

Between December 93 and December 97, 36 consecutive patients with negative findings on IVP and still suspected ureteral obstruction were referred for transrectal or transvaginal endosonography. Patients mean age was 63 years and all of them presented clinically obvious symptoms such as colic pain and miction disturbances.

RESULTS

In 31 of 36 patients (86%) 3D endosonography was diagnostic although previous IVP was negative. Reasons for ureteral obstructions were ureteral calculi in 23, urological tumours in 5 and rectal carcinoma in two cases. In one patients a gynecological tumour caused the symptomatology. In the remaining 5 patients CT/MRT or invasive retrograde ureterography/ureteroscopy had to be performed for the final diagnosis.

CONCLUSIONS

The use of 3D endosonography shows encouraging results in the diagnosis of distal ureteral pathologies. In case of negative findings on IVP it should therefore precede invasive diagnostic modalities or cost intensive imaging techniques.

New endoureteral double-J stent resists extrinsic ureteral compression

The disadvantages of highly flexible endoureteral (double J) stents in the face of tumor-induced extrinsic ureteral compression are a consequence of insufficient cross-sectional stability, leading to stent compression and thus to hydronephrosis or pyonephrosis. The newly developed tumor stent, which is used in cases of tumor-induced ureteral compression, is available in sizes from 6F to 8F in diameter and 24 to 32 cm in length. The shaft consists of a combination of high-stability plastics that presents sufficient elasticity in length. Both ends are made of extremely elastic J parts, guaranteeing stable fixation. Compared with common double-J stents with the same outside diameter, the tumor stent possesses a comparable interior diameter and compared with available stents promises sufficient interior flow in the face of extrinsic diseases. The application can be undertaken using well-known endoscopic techniques, needs no special instrumentation, and entails no learning curve. To date, 49 stents were placed at our urologic departments without any problems, the latest stent remaining for 15 months. Tumor-induced compression or a higher rate of encrustation were not seen. All patients tolerated these stents well. In our opinion, the new stabilized endoureteral stent can be seen as a better solution than percutaneous nephrostomy or frequent stent changing to tumor-induced extrinsic ureteral compression.

Comparative study of the repair kinetics of chromosomal aberrations and DNA strand breaks in proliferating and quiescent CHO cells

Repair kinetics observable at the level of exchange-type chromosomal aberrations (dicentric chromosomes), using fractionation and delayed-plating techniques, have been compared with repair kinetics of radiation-induced DNA double-strand breaks, measured with PFGE, and with repair kinetics of all strand breaks, measured with the alkali-unwinding technique. Only data from quiescent or proliferating CHO K1 cells obtained in the same laboratory were used. We determined repair kinetics in terms of the time constant tau (equal to half-time/log(e)2). The repair kinetics (tau approximately 11-14 min) observed in the split-dose formation of dicentric chromosomes agrees with fast repair kinetics of double-strand breaks (tau approximately 11-13 min), thus permitting us to identify the latter as the 'primary lesions' whose pairwise interaction leads to the beta D2 yield term of the aberrations. The repair kinetics observed for dicentric chromosomes formed under delayed-plating conditions (tau approximately 75 min), which mainly affects the alpha D yield term, is attributed to an intermediate interchromosomal product temporarily existing in the course of aberration formation; it is suggested that this product is mechanistically correlated with the slow repair kinetics of 'clustered damage' to DNA seen with the applied molecular methods (tau approximately 90 min).

Kinetics of the formation of chromosome aberrations in X-irradiated human lymphocytes: analysis by premature chromosome condensation with delayed fusion

Human lymphocytes irradiated with graded doses of up to 5 Gy of 150 kV X rays were fused with mitotic CHO cells after delay times ranging from 0 to 14 h after irradiation. The yields of dicentrics seen under PCC conditions, using C-banding for centromere detection, and of excess acentric fragments observed in the PCC experiment were determined by image analysis. At 4 Gy the time course of the yield of dicentrics shows an early plateau for delay times up to 2 h, then an S-shaped rise and a final plateau which is reached after a delay time of about 8 to 10 h. Whereas the dose-yield curve measured at zero delay time is strictly linear, the shape of the curve obtained for 8 h delay time is linear-quadratic. The linear yield component, alpha D, is formed entirely in the fast process manifested in the early plateau, while component beta D2 is developed slowly in the subsequent hours. Analysis of the kinetics of the rise of the S-shaped curve for yield as a function of time leads to the postulate of an "intermediate product" of pairwise DNA lesion interaction, still fragile when subjected to the stress of PCC, but gradually processed into a stable dicentric chromosome. It is concluded that the observed difference in the kinetics of the alpha and beta components explains a number of earlier results, especially the disappearance of the beta component at high LET, and opens possibilities for chemical and physical modification of the beta component during the extended formation process after irradiation observed here.

Influence of ara A on the formation of dicentrics in irradiated quiescent CHO cells

CHO K1-cells, arrested in G0/G1 phase were irradiated with graded doses of 150-kV X-rays, and the dicentric chromosome aberrations in the first metaphase after reincubation in full growth medium were evaluated. When 500 microM ara A was administered at least 1 h before irradiation, maximal enhancement of the dicentric yield was obtained under 'immediate plating' conditions as well as under 'delayed plating' conditions, and under both conditions only the linear component alpha D of the aberration yield was affected. Since ara A had no effect upon the number of induced dsbs, as measured with PFGE at doses up to 100 Gy, the action pathway of ara A is suggested to be the repair/misrepair process manifested in the linear component of the dicentric yield. By varying the time at which either ara A at 37 degrees C was administered before irradiation or ara A at 4 degrees C was added after irradiation, it was observed that the repair step sensitive to ara A was completed within about 5 min after irradiation. This is in agreement with other observations of ara A action upon a fast repair step. The conversion of DNA single-strand breaks or base damage sites into double-strand breaks as a consequence of polymerase beta inhibition by ara A would explain the present results.

Kinetics of chromosome lesion repair in synchronized quiescent and proliferating CHO cells

The induction of chromosome aberrations by X-rays was investigated in synchronized quiescent and proliferating CHO-K1 cells. Kinetics of chromosome lesion repair was studied using the method of fractionated irradiation. In both cell types the time-course of repair during fractionation intervals followed first-order kinetics. Comparison with kinetic data reported on DNA double-strand break repair supports the hypothesis that DNA double-strand breaks are the lesions underlying chromosome aberration formation. Quiescent CHO cells showed higher aberration yields than proliferating cells, and chromosome lesion repair was faster in quiescent cells. This correlation can be interpreted in terms of a higher degree of repair synchronism during pairwise lesion interaction. The effect of delayed plating on aberration induction was studied in quiescent cells. The time-course of repair active during the delayed plating interval followed first-order kinetics. The kinetics observed in delayed plating experiments is slower than the repair kinetics observed in fractionation experiments, suggesting the involvement of two different processes.