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J Nyman

Publications and source records attributed to J Nyman.

At least 19 recordsLinked to original sources
PubMed2006

Stability in a denitrifying fluidized bed reactor.

This study evaluates changes in the microbial community structure and function of a pilot-scale denitrifying fluidized bed reactor during periods of constant operating conditions and periods of perturbation. The perturbations consisted of a shutdown period without feed, two disturbances in which biofilms were mechanically sheared from carrier particles, and a twofold step increase in feed nitrate concentration. In the absence of perturbations, nitrate removal was stable and consistently greater than 99%. The structure and dynamics of the microbial community were studied using cloning and sequencing techniques and terminal restriction fragment length polymorphism (T-RFLP) of the SSU rRNA gene. Under unperturbed operating conditions, stable function was accompanied by high constancy and low variability of community structure with the majority of terminal restriction fragments (T-RFs) appearing throughout operation at consistent relative abundances. Several of the consistently present T-RFs correlated with clone sequences closely related to Acidovorax (98% similarity), Dechloromonas (99% similarity), and Zoogloea (98% similarity), genera recently identified by molecular analyses of similar systems. Significant changes in community structure and function were not observed after the shutdown period. In contrast, following the increase in loading rate and the mechanical disturbances, new T-RFs appeared. After both mechanical disturbances, function and community structure recovered. However, function was much more resilient than community structure. The similarity of response to the mechanical disturbances despite differences in community structure and operating conditions suggests that flexible community structure and potentially the activity of minor members under nonperturbation conditions promotes system recovery.

Biodegradation, Environmental↗
PubMed2005

Stent insertion or endoluminal brachytherapy as palliation of patients with advanced cancer of the esophagus and gastroesophageal junction. Results of a randomized, controlled clinical trial.

SUMMARY: Esophageal cancer often presents as advanced stage disease with a dismal prognosis, with only 10-15% of patients surviving 5 years. Therefore, in a large proportion of patients, palliative treatment is the only option available. The aim of this study was to prospectively compare the palliative effect of self-expandable stent placement with that of endoluminal brachytherapy regarding the effect on quality of life and on specific symptoms. Sixty-five patients with advanced cancer of the esophagus or gastroesophageal junction were randomized to treatment with either an Ultraflex expandable stent or high-dose-rate endoluminal brachytherapy with 7 Gy x 3 given in 2-4 weeks. Clinical assessment and health-related quality of life (HRQL) were measured at inclusion and 1, 3, 6, 9 and 12 months later. The HRQL was measured with standardized questionnaires (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Oesophageal Module and Hospital Anxiety and Depression Scale). Twenty-eight patients completed the stent treatment and 24 patients the brachytherapy. The group of patients treated with stent reported significantly better HRQL scores for dysphagia (P < 0.05) at the 1-month follow-up, but most other HRQL scores, including functioning and symptom scales, deteriorated. Among brachytherapy-treated patients, improvement was found for the dysphagia-related scores at the 3-months follow-up, whereas other significant changes of scores were few. The median survival time was comparable in the two groups (around 120 days). In conclusion, insertion of self-expandable metal stents offered a more instant relief of dysphagia compared to endoluminal brachytherapy, but HRQL was more stable in the brachytherapy group.

Aged↗
PubMed2003

Time factor for acute tissue reactions following fractionated irradiation: a balance between repopulation and enhanced radiosensitivity.

Experimental data for acute radiation-induced skin reactions are reviewed. These show that for dose fractionation schedules with gaps, repopulation is initiated after a lag period. After this lag period, the isoeffective dose for a given level of skin reaction first increases rapidly, but then slows. The timing of the lag period is related to the total turnover time of the tissue under investigation and, for example, is shorter in rodent skin than in pig or human skin. At the point when accelerated repopulation is initiated, there is a major shortening of the turnover time of the target cell population. At this time, there is evidence, for a short period, for an increase in radiosensitivity of the surviving stem cells in a number of acutely responding normal tissues. This effect is clearly illustrated by the results of experiments using sequential dose fractionation schedules. Prolongation of the schedule from 'short' to schedules that include irradiation over the period when the cell turnover is accelerated is associated with a marked increase in tissue radiosensitivity. Clinically, this is best illustrated by a comparison of the effects of accelerated fractionation schedules, involving multiple fractions/day, with daily fractionation schedules. The increase in radiosensitivity produced by the prolongation of the treatment from 2 to 4-5 weeks was equivalent to > or =1 Gy day(-1). Comparable findings were obtained from animal studies. In the oral mucosa of mice, the initiation of accelerated cell proliferation in surviving cells is associated with the loss of dose sparing by subsequent dose fractionation due to the loss of the capacity to repair sublethal damage. Studies in pig and human skin have indicated that increased radiosensitivity is associated with a loss of cells in the G1 phase of the cell cycle. A collation of these two sets of findings suggests that the repair of sublethal damage takes place over this phase of the cell cycle. One clinical implication of these findings is that the alpha/beta ratio for acute skin reaction changes with the length of the overall treatment time; it is approximately 4.0 Gy for 'short' fractionation schedules that avoid any shortening of the cell cycle time. This increases to 11.2-13.3 Gy for schedules given in 3-4 weeks and to approximately 35 Gy for schedules given in 5-6 weeks. Results for pig skin were in total agreement with those for human skin.

Animals↗
PubMed2001

Normal tissue response to low doses of radiotherapy assessed by molecular markers--a study of skin in patients treated for prostate cancer.

The aim of this study was to evaluate normal tissue response by molecular markers to multifraction low doses of ionizing radiation, with the focus on changes in repopulation, estimated using Ki-67 as the proliferation marker, and on expressions of the p53 and p21 proteins, identified as key proteins in the DNA damage checkpoint. Repeated skin biopsies were taken from patients treated for prostate cancer with radiotherapy. The expressions of Ki-67, p53 and p21 of the keratinocytes in the basal cell layer of the epidermis were quantified immunohistochemically. The dose to the basal layer was 1.1 Gy per fraction, given five times per week for seven weeks. The indices of the three markers were determined over the whole period. A significant suppression of the Ki-67 index was observed during the first weeks, followed by a significant gradual increase in the Ki-67 index over the last weeks. The p53 and p21 protein levels were almost zero in the unirradiated skin. Upon irradiation, both the p53 and p21 index increased in a pattern very congruent to the Ki-67 index. In conclusion, daily fractions of about 1 Gy to the skin resulted in, for the keratinocytes in the basal layer, a cell growth arrest for a couple of weeks and a subsequent acceleration in repopulation during the following weeks of irradiation. The present findings also provided novel insights into the role of the p53/p21 pathway in the response of a normal epithelium to ionizing radiation as it is applied in radiotherapy.

Biomarkers↗
PubMed2001

Accuracy of tele-oncology compared with face-to-face consultation in head and neck cancer case conferences.

Telemedicine was introduced for weekly tumour case conferences between Sahlgrenska University Hospital and two district hospitals in Sweden. The accuracy of tele-oncology was determined using simulated telemedicine consultations, in which all the material relating to each case was presented but without the patient in person. The people attending the conference were asked to determine the tumour ('TNM') classification and treatment. The patient was then presented in person, to give the audience the opportunity to ask questions and perform a physical examination. Then a new discussion regarding the tumour classification and the treatment plan took place, and the consensus was recorded. Of the 98 consecutive patients studied in this way, 80 could be evaluated by both techniques. Of these 80, 73 (91%) had the same classification and treatment plan in the telemedicine simulation as in the subsequent face-to-face consultation. In four cases the TNM classification was changed and for three patients the treatment plan was altered. The specialists also had to state their degree of confidence in the tele-oncology decisions. When they recorded uncertainty about their decision, it was generally because they wanted to palpate the tumour. In five of the seven patients with a different outcome, the clinical evaluation was stated to be dubious or not possible. The results show that telemedicine can be used safely for the management of head and neck cancers.

Aged↗
PubMed2000

Comparison of DNA repair protein expression and activities between human fibroblast cell lines with different radiosensitivities.

In order to investigate the molecular basis of variation in response to ionising radiation (IR) in radiotherapy patients, we have studied the expression of several genes involved in DNA double-strand break repair pathways in fibroblast cell lines. Ten lines were established from skin biopsies of cancer patients with different normal-tissue reactions to IR, and 3 from a control individual. For all 10 test cell lines, the cellular radiosensitivity was also known. Using Western blots we measured, in non-irradiated cells, the basal expression levels of ATM, Rad1 and Hus1, involved in the control of cellular DNA damage checkpoints, together with DNA-PKcs, Ku70, Ku80; XRCC4, ligaseIV and Rad51, involved in radiation- induced DSB repair. We also analysed the in vitro enzymatic activities, under non-irradiated conditions, of the DNA-PK and XRCC4/ligaseIV complexes. The levels of expression of the different proteins were similar in all the cell lines, but the activities of the DNA-PK and XRCC4/ligaseIV complexes showed some differences. These differences did not correlate with either the normal tissue response of the patient in vivo or with cellular radiation sensitivity in vitro. The activity differences of these enzyme complexes, therefore, do not account for the variation of responses seen between patients.

Blotting, Western↗
PubMed2000

Cardiopulmonary resuscitation skills in nurses and nursing students.

The purpose of this study is to describe the basic cardiac life-support (BLS) skills of nurses and nursing students in southern Finland and Hungary, and to assess the influence of resuscitation teaching and other group characteristics on performance. The data for the study were collected in the spring and autumn of 1997. The study group consisted of 75 nurses from Helsinki University Central Hospital's medical outcome unit, 188 final term students in four nursing institutes in Uusimaa county and 35 final term students in a Hungarian institute of nursing. A total of 298 people (34 men and 264 women) participated in the study. Background information was collected using a structured questionnaire devised specifically for this study. Resuscitation skills were measured using the Skillmeter Anne manikin. The manikin was placed supine during the test. After completing the questionnaire, every participant attempted resuscitation on the manikin - which was supplied with a printer - for 4 min. The results were printed out and attached to the questionnaires. The data were analysed using two-way frequency tables and logistic regression. Statistical differences were calculated using the chi(2)-test. The results showed that 53% of the participants had studied resuscitation during the last 6 months, but 7% had never participated in resuscitation teaching. Before testing, 55% of the participants estimated that their resuscitation skills were good. The results showed that 36% first assessed the patient's response, 67% opened the airway but only 3% determined pulselessness before starting to resuscitate. Twenty-one percent of the participants compressed correctly for at least half of the test and 33% ventilated correctly at least half of the time. Logistic regression showed that the best predictors for good response assessment skills went to those who were nursing students who had studied resuscitation skills sometime during the previous 6 months. The best predictor of the skill to open the airway was a positive attitude towards personal cardiopulmonary resuscitation (CPR) skills, i.e. self-confidence. The predictor for adequate skills in artificial ventilation was that they belonged in the group of nursing students who had benefited from recent resuscitation training (<6 months). In conclusion, the skills of the participants of the study can not be considered adequate in terms of an adequate and prompt assessment of the need for resuscitation, and a 50% success rate in artificial ventilation and chest compression.

Adult↗
PubMed2000

The cost of work-related physical assaults in Minnesota.

OBJECTIVE: To describe the long-term productivity costs of occupational assaults. DATA SOURCES/STUDY SETTING: All incidents of physical assaults that resulted in indemnity payments, identified from the Minnesota Department of Labor and Industry (DLI) Workers' Compensation system in 1992. Medical expenditures were obtained from insurers, and data on lost wages, legal fees, and permanency ratings were collected from DLI records. Insurance administrative expenses were estimated. Lost fringe benefits and household production losses were imputed. STUDY DESIGN: The human capital approach was used to describe the long-term costs of occupational assaults. Economic software was used to apply a modified version of Rice, MacKenzie, and Associates' (1989) model for estimating the present value of past losses from 1992 through 1995 for all cases, and the future losses for cases open in 1996. PRINCIPAL FINDINGS: The total costs for 344 nonfatal work-related assaults were estimated at $5,885,448 (1996 dollars). Calculation of injury incidence and average costs per case and per employee identified populations with an elevated risk of assault. An analysis by industry revealed an elevated risk for workers employed in justice and safety (incidence: 198/100,000; $19,251 per case; $38 per employee), social service (incidence: 127/100,000; $24,210 per case; $31 per employee), and health care (incidence: 76/100,000; $13,197 per case; $10 per employee). CONCLUSIONS: Identified subgroups warrant attention for risk factor identification and prevention efforts. Cost estimates can serve as the basis for business calculations on the potential value of risk management interventions.

Adult↗
PubMed1998

Describing patients' normal tissue reactions: concerning the possibility of individualising radiotherapy dose prescriptions based on potential predictive assays of normal tissue radiosensitivity. Steering Committee of the BioMed2 European Union Concerted Action Programme on the Development of Predictive Tests of Normal Tissue Response to Radiation Therapy.

Clinical radiotherapeutic doses are limited by the tolerance of normal tissues. Patients given a standard treatment exhibit a range of normal tissue reactions, and a better understanding of this individual variation might allow for individualisation of radiotherapeutic prescriptions, with consequent improvement in the therapeutic ratio. At present, there is no simple way to describe normal tissue reactions, which hampers communication between clinic and laboratory and between groups from different centres. There is also no method for comparing the severity of reactions in different normal tissues. This arises largely because there is no definition of a "normal" reaction, an "extreme" reaction or the particular term "over-reactor" (OR). This report proposes definitions for these terms, as well as a simple terminology for describing normal tissue reactions in patients having radiotherapy. The "normal" range represents the individual variation in normal tissue reactions amongst large numbers of patients treated in the same way which is within clinically acceptable limits. The term "OR" is applied to an individual whose reaction is more severe than the normal range but also implies that this forced a major change in the radiotherapeutic prescription or that the reactions were very severe or fatal. A "severe OR" would develop serious problems with a typical radical dose, while an "extreme OR" would have such difficulties at a much lower dose. To describe the normal range, a numerical scale is suggested, from 1 to 5, resistant to sensitive. The term "highly radiosensitive" (HR) is suggested for category 5. An "informal" relative scale, as suggested here, is quick and simple. It should allow comparison between different hospitals, compensate for differences in radiotherapeutic dose and technique and allow comparison of reactions between different anatomical sites. It should be adequate for discriminating patients at the extremes of the normal range from those at the centre. It is hoped that the definitions and terminology proposed here will aid communication in the field of predictive testing of normal tissue radiosensitivity.

Follow-Up Studies↗
PubMed1998

The apparent fracture toughness of acrylic bone cement: effect of three variables.

In cemented arthroplasties, pores are almost invariably present at one or more of the so-called 'weak-link' zones (namely, the bone-cement interface, the cement mantle and the cement-implant interface). In the clinical milieu, arthroplasties are frequently subjected to cyclical loading. These conditions underscore the significance of the apparent fracture toughness (KISR) of the cement. The present work is an investigation of the effect of three variables on KISR of three commercial formulations of bone cement (namely, CMW3, PalacosR and Osteopal) measured using straight-sided chevron notched short rod specimens. For CMW3, the effect of mixing method was studied, with all cement constituents having been stored at ambient laboratory environment prior to being mixed. The highest KISR was obtained from material that was obtained from exposing the cement constituents to a passive vacuum for 20 s and then mixing them in a machine that subjected them to simultaneous mechanical mixing and centrifugation. For Palacos R, the effects of two variables [storage temperature of the cement constituents prior to being mixed (4 degrees C versus 21 degrees C) and mixing method (hand mixing versus vacuum mixing)] (taken individually) were studied. It was found that only mixing method exerts a significant effect on KISR. When room-temperature stored constituents were vacuum mixed, the KISR values for a low-viscosity cement (Osteopal) and a medium-viscosity cement of very similar composition (Palacos R) are not significantly different, indicating that the fracture resistance of bone cement is influenced more by its composition than its viscosity.

Acrylic Resins↗
PubMed1998

Accelerated hyperfractionated radiotherapy combined with induction and concomitant chemotherapy for inoperable non-small-cell lung cancer--impact of total treatment time.

Tumour cell proliferation during conventionally fractionated radiotherapy (RT) can negatively influence the treatment outcome in patients with unresectable non-small-cell lung cancer (NSCLC). Accelerated and hyperfractionated RT may therefore have an advantage over conventional RT. Moreover, earlier studies have suggested improved survival with addition of cisplatin-based chemotherapy (CT). We present here the results of combined treatment with induction and concomitant CT and accelerated hyperfractionated RT in a retrospective series of patients with advanced NSCLC. Between August 1990 and August 1995, 90 consecutive patients, aged 42-77 years (median 63 years), with locally advanced unresectable or medically inoperable NSCLC and good performance status were referred for treatment: stage: I 23%, IIIa 37%, IIIb 40%. Patient histologies included: squamous cell carcinoma 52%, adenocarcinoma 34% and large cell carcinoma 13%. The treatment consisted of two courses of CT (cisplatin 100 mg/m2 day 1 and etoposide 100 mg/m2 day 1-3 i.v.), the second course given concomitantly with RT. The total RT dose was 61.2-64.6 Gy, with two daily fractions of 1.7 Gy. A one-week interval was introduced after 40.8 Gy to reduce acute toxicity, making the total treatment time 4.5 weeks. Concerning toxicity, 33 patients had febrile neutropenia, 10 patients suffered from grade III oesophagitis and 7 patients had grade III pneumonitis. There were two possible treatment-related deaths, one due to myocardial infarction and the other due to a pneumocystis carinii infection. The 1-, 2- and 3-year overall survival rates were 72%, 46% and 34%, respectively; median survival was 21.3 months. Fifty-nine patients had progressive disease: 21 failed locoregionally, 29 had distant metastases and 9 patients had a combination of these. Pretreatment weight loss was the only prognostic factor found, except for stage. However, the results for stage IIIb were no different from those for stage IIIa. We conclude that the survival results compare favourably with those of most other studies with a manageable toxicity.

Adult↗
PubMed1997

Anti-Ro (SSA) antibodies in rheumatoid arthritis patients with gold-induced side effects.

The purpose of our study was to investigate the significance of the presence of anti-Ro antibodies found by us in an earlier study of rheumatoid arthritis (RA) patients with gold-induced side effects. Sera of 29 anti-Ro (SSA) positive RA patients who had gold-induced side effects were studied. All sera were examined by Western blot using recombinant antigens, encoding the Ro 60 kD and the La proteins. HLA typing was done in all patients. Thirteen patients reacted only with the Ro 52 kD antigen and all had severe skin eruptions caused by gold therapy. Another ten patients who reacted only with the Ro 60 kD antigen had other side effects to gold (six had proteinuria and four leucopenia). Six patients who reacted to all three antigens (Ro 52 kD, Ro 60 kD and La) had secondary Sjögren's syndrome. No significant statistical differences were noted in the incidence of HLA-DR3 between the subgroups of patients. Our data indicated that antibodies to the Ro 52 kD antigen are associated with skin eruptions in RA patients treated with gold.

Aged↗
PubMed1997

Effects of irradiation on the biomechanics of osseointegration. An experimental in vivo study in rats.

The present study reports on the late effects of increasing doses of radiation on the biomechanics of commercially pure titanium implants (fixtures) installed in the proximal tibia in 26 rats. Twelve weeks after various doses (10, 20, 30, and 35 Gy) of irradiation, the fixtures were inserted into rat tibiae, and after another eight weeks these were tested mechanically in vivo. Acute dose dependent skin reactions developed after all doses except 10 Gy, but most subsided within two to three weeks. There was a statistically significant reduction in torsion but the pull-out load was not significantly reduced for single doses up to 30 Gy. Histological analysis showed that bone remodelling was impaired. Shear stresses and shear moduli were estimated for the bone-implant interface and in the surrounding bone tissue. These estimated stresses and moduli were not found to be correlated to the dose of radiation.

Animals↗
PubMed1996

Prognostic factors for acute and late skin reactions in radiotherapy patients.

PURPOSE: Patients treated with identical radiotherapy schedules show a substantial variation in the degree of acute and late normal tissue reactions. To identify any possible contributing factors to this phenomenon, we have analyzed the treatments of 402 breast cancer patients. METHODS AND MATERIALS: The patients received adjuvant postoperative radiotherapy between 1972 and 1985 and have been followed up since then. Multivariate analyses were performed with peak reflectance erythema and peak acute reaction score as endpoints for the acute reactions, and with progression rate of telangiectasia as well as telangiectasia score as endpoints for the late reactions. Twenty patient- and treatment-related factors were tested such as age, menopausal status, hemoglobin level, serum calcium, smoking habits, hypothyroidism, diabetes, hypertension, blood pressure, cardiovascular and autoimmune disease, the influence of hormone therapy and chemotherapy, pretreatment reflectance value, acute skin reactions, radiation quality, individual dose, bilateral fields, and the total effect (TE) for the dose schedule applied. RESULTS: The TE was a strong prognostic factor for all endpoints. In addition to TE, blood pressure was prognostic for the peak erythema measured by reflectance spectrophotometry, and the pretreatment reflectance value was prognostic for the acute score. The only independent prognostic factors found for the progression of skin telangiectasia and telangiectasia score except for TE were the individual dose and the acute skin reactions. CONCLUSIONS: These factors explained at most about 30% of the variance describing the total patient-to-patient variability for each endpoint. The remaining variability is still unexplained but may be related to individual differences in cellular radiosensitivity, partly determined by genetic variations and partly by unknown epigenetic factors.

Adult↗
PubMed1996

Normal tissue radiosensitivity--how important is it?

The success of radiotherapy in eradicating tumours depends on the total radiation dose, but what limits this dose is the tolerance of the normal tissues within the treatment volume. Selection of the appropriate dose for all patients is based on a balance between minimising the incidence of severe normal tissue complications and maximizing the probability of local control. In patients treated to the same radical dose, a wide range of reactions is seen; in many clinical situations, radical doses are limited by the minority of patients whose normal tissues are particularly sensitive. Clinical studies of radiotherapy reactions have demonstrated that a large part of the spectrum of normal tissue reactions, perhaps as much as 80%, is due to differences in individual normal tissue sensitivity. This suggests that it might be possible to measure this sensitivity and to change treatment accordingly. The main objective of normal tissue sensitivity testing is to permit dose escalation without increased normal tissue complication rates in patients with more resistant normal tissues. Calculations suggest that the most "resistant' 40% of patients could be dose escalated by 17%-18%, which is likely to be associated with significant gains in local control, perhaps by as much as 34%-36%; this should translate into an increase in overall survival. It should also be possible to identify those relatively few patients who suffer serious normal tissue morbidity with conventional doses. Thus, if successful, predictive testing of normal tissue response should improve the therapeutic ratio of radiotherapy.

Forecasting↗
PubMed1996

A randomised placebo controlled study with ondansetron in patients undergoing fractionated radiotherapy.

BACKGROUND: There are few randomised studies comparing anti-emetic drugs for the prevention of nausea and vomiting in patients treated with fractionated radiotherapy. The aim of the study was to compare the anti-emetic efficacy of 8 mg dose ondansetron twice a day with placebo. MATERIALS AND METHODS: One hundred eleven patients who were to commence a course of 10 or more daily fractionated radiotherapy including the abdomen were included in the study. The patients recorded daily emesis, nausea and bowel habit and graded weekly symptoms of nausea, vomiting, diarrhoea and lack of appetite. The EORTC C30 questionnaire was completed. RESULTS: 67% of patients given ondansetron had complete control of emesis compared with 45% of patients with placebo (P < 0.05). The number of emetic episodes recorded on the worst day was 1.4 for the ondansetron group and 3.1 for the placebo group (P < 0.01). Patients given ondansetron had fewer days with emesis and nausea compared with placebo (P < 0.05). The mean sum score of patients weekly grading of symptoms showed that the ondansetron group had less inconvenience than the placebo group (P < 0.05). This difference persisted during the first three weeks, but not thereafter. Similarly, some quality of life measures showed significant differences in favour of the ondansetron group. More patients (n = 13) withdrew due to lack of efficacy in the placebo group compared with patients (n = 8) in the ondansetron group. CONCLUSIONS: The present study illustrates that prophylactic anti-emetic administration of ondansetron is effective in preventing nausea and vomiting in patients undergoing fractionated radiotherapy of the abdomen.

Abdomen↗
PubMed1995

Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer.

PURPOSE/OBJECTIVE: To determine if the radiosensitivity of normal human skin fibroblasts, measured in early passage cultures, is significantly correlated with the degree of acute or late normal skin damage in patients treated for breast cancer with radiotherapy. METHODS AND MATERIALS: In the 1970s, a series of breast cancer patients was treated at the Department of Oncology in Gothenburg, Sweden with postoperative irradiation to the parasternal region. Patients were treated bilaterally using different fractionation schedules and doses to the right and left fields. Peak acute reactions were scored on a six-point scale, and skin erythema was measured by reflectance spectrophotometry. Telangiectasia was graded over time on a six-point scale. In April 1992, two small skin biopsies were obtained from 22 patients in two treatment groups (i.e., four dose-fractionation schedules) and, using either delayed or immediate plating, fibroblast radiosensitivity was measured in early passage cultures by clonogenic survival, after high and low dose-rate irradiations. Survival at 2.0 Gy (SF2) was calculated from complete survival curves. RESULTS: To test assay reproducibility, SF2 values derived from paired biopsies of the same patient (12 cases) were compared. A reasonably good correlation (p = 0.075) was obtained for SF2s determined by high dose-rate irradiations with immediate plating, but not for delayed plating or low dose-rate treatments. The median coefficient of variation in the replicate SF2s after high dose-rate treatment and immediate plating was 13%, suggesting that the poor correlation in paired SF2 values is due to the magnitude of the uncertainty in SF2 relative to the overall spread in SF2 values between patients (CV = 28%). Individual SF2 values and averaged values from patients with data from two biopsies were compared with the acute and late clinical reactions. A significant negative correlation was found between SF2 and relative clinical response, but only when averaged high dose-rate SF2 values and telangiectasia scores were compared. There was no significant correlation between average SF2 values and acute responses or between individual SF2 measurements and either the acute or late clinical response. CONCLUSION: The results of this study suggest that the degree of late telangiectasia is at least partially dependent upon the intrinsic cellular radiosensitivity of normal fibroblasts, but the relationship is not clear cut. Multiple replicate assays are necessary to obtain reliable estimates of fibroblast SF2 values using current techniques.

Biopsy↗