P15.14.B Radionecrosis versus progression in brain tumors: results of a promising MRI tools

Background

Distinguish between radiation necrosis (RN) and tumor progression, in patients with irradiated primary or metastatic brain tumors, is a diagnostic challenge. Also the use of new MRI sequences, like diffusion, perfusion-weighted and spectroscopy, or PET with new amino acid tracers, is not always able to differentiate these two entities.To overcome this crucial problem, encouraging results have been obtained using the analysis of delayed contrast extravasation MRI to calculate high resolution maps, called “treatment response assessment maps” (TRAMs). Aim of this exploratory analysis is to assess TRAM ability in differentiate between radiation effect and tumor progression in a small cohort of brain tumor patients treated with radiation therapy (RT).

Material and Methods

Thirty-four patients irradiated for primary and metastatic brain tumors were evaluated. 12 patients have primary brain tumors, 22 patients have brain metastases from different solid tumors. Distinguish by histological subtypes and type of treatment, the 12 patients with primary brain tumors were: 8 glioblastoma, 2 anaplastic astrocitoma, 1 pleomorphic xanthoastrocytoma WHO grade II, and 1 anaplastic xanthoastrocytoma WHO grade III, treated with surgery followed by RT and concomitant and\or adjuvant chemotherapy with temozolomide. Among brain metastatic patients, primary tumor was: 18 non-small cell lung cancer, 2 malignant melanoma, 1 breast cancer and 1 renal cell carcinoma. All of them were treated with stereotactic radiosurgery at the dose of 20-24Gy in 1fraction, or with hypofractionated stereotactic radiotherapy at the dose of 27-30Gy in 3fractions. All images were uploaded and elaborate into the image workstation ([Brainlab AG, Olof-Palme-Straße 9, 81829 Munich]). TRAMs were calculated by subtracting T1 MRI images acquired 5 minutes after contrast injection from the T1 MRI images acquired 60-105 minutes later. On TRAMs, radiation effects appeared as red areas whereas persistent tumoral lesion appeared as blue areas.

Results

From February 2021, 34 patients have been evaluated, in a prospective study, with this novel MRI modality. During their follow-up, 13patients (38%) showed a clinicoradiologic suspicion of a persistent tumoral lesion or progressive disease, and 21 (62%) a suspicion of RN. For 14patients a brain MET-PET has been performed. TRAMs analysis have shown a fair agreement with clinicoradiologic diagnosis, perfusion-weighted MRI, and PET imaging. Moreover, 7 patients underwent surgical resection, with histopathological confirm of persistent disease in 4 and radionecrosis in 3.

Conclusion

These preliminary results show the ability of TRAMs evaluation in distinguish between RN and progressive disease. The recruitment of new patients continues, and further evaluations are ongoing to evaluate sensitivity and positive predictive value of TRAMs analysis.

QSAR models for biocides: The example of the prediction of Daphnia magna acute toxicity

Biocides are multi-component products used to control undesired and harmful organisms able to affect human or animal health or to damage natural and manufactured products. Because of their widespread use, aquatic and terrestrial ecosystems could be contaminated by biocides. The environmental impact of biocides is evaluated through eco-toxicological studies with model organisms of terrestrial and aquatic ecosystems. We focused on the development of in silico models for the evaluation of the acute toxicity (EC₅₀) of a set of biocides collected from different sources on the freshwater crustacean Daphnia magna, one of the most widely used model organisms in aquatic toxicology. Toxicological data specific for biocides are limited, so we developed three models for daphnid toxicity using different strategies (linear regression, random forest, Monte Carlo (CORAL)) to overcome this limitation. All models gave satisfactory results in our datasets: the random forest model showed the best results with a determination coefficient r² = 0.97 and 0.89, respectively, for the training (TS) and the validation sets (VS) while linear regression model and the CORAL model had similar but lower performance (r² = 0.83 and 0.75, respectively, for TS and VS in the linear regression model and r² = 0.74 and 0.75 for the CORAL model).

Classification of a Naïve Bayesian Fingerprint model to predict reproductive toxicity$

Using data from the Leadscope database and Procter and Gamble researchers (1172 compounds after data curation) a new classification model to predict reproductive toxicity was developed. The model is based on Naïve Bayesian methods that use the fingerprint "extended connectivity fingerprint 2". Bits generated by the fingerprint are used from the models as descriptors to discriminate between the two classes. This technique permits the creation of a model without the use of descriptors. After a study on the probability scores, the Naïve Bayesian Fingerprint model shows a good performance on reproductive toxicity. The Matthews Correlation Coefficient value was ≥0.4 in validation. The development of new models to predict complex endpoints such as reproductive toxicity is increasingly requested, with reference also to the REACH legislation in Europe or TSCA in the USA.

Procedures and recommended times in the care process of the patient with pancreatic cancer: PAN-TIME consensus between scientific societies

PURPOSE

Pancreatic cancer (PC) is a disease with bad prognosis. It is usually diagnosed at advanced stages and its treatment is complex. The aim of this consensus document was to provide recommendations by experts that would ameliorate PC diagnosis, reduce the time to treatment, and optimize PC management by interdisciplinary teams.

METHODS

As a consensus method, we followed the modified Delphi methodology. A scientific committee of experts provided 40 statements that were submitted in two rounds to a panel of 87 specialists of 12 scientific societies.

RESULTS

Agreement was reached for 39 of the 40 proposed statements (97.5%).

CONCLUSIONS

Although a screening of the asymptomatic population is not a feasible option, special attention to potential symptoms during primary care could ameliorate early diagnostic. It is especially important to decrease the period until diagnostic tests are performed. This consensus could improve survival in PC patients by decreasing the time to diagnose and time to treatment and by the implementation of multidisciplinary teams.

Synergic development of pharmacokinetics and bioanalytical methods as support of pharmaceutical research

The development of pharmacokinetics led this science to achieve a relevant role in the investigation of new chemical entities for therapeutic application, and has allowed a series of new useful realizations of out of patent drugs like prolonged release and delayed release formulations, therapeutic delivery system (TDS) for drugs to be active in systemic circulation avoiding the first pass effect, orodispersible and effervescent formulations, intramuscular and subcutaneous depot formulations acting over a long period, oral inhalatory systems, and drug association at fixed dose. The above applications had pharmacokinetics as protagonist and have required the support from bioanalytical methods to assay drug concentrations, even in pg·mL(-1) of plasma, that really have paralleled the synergic development of pharmacokinetics.The complexity of the above realizations required specific guidelines from the regulatory authorities, mainly the US FDA and EU EMA, which have normalized and, in most cases, simplified the above applications admitting some waivers of in vivo bioequivalence.However, this review highlights some critical points, not yet focused on by operating guidelines, which need to be clarified by regulatory authorities. One of the most relevant issues is about the planning and conducting bioavailability and bioequivalence trials with endogenous substances, that possess own homeostatic equilibria with fluctuations, in some cases with specific rhythms, like melatonin and female sex hormones. The baseline subtraction required by guidelines to define the net contribute to the exogenous absorbed drug in most cases is a non-solvable problem.

Paradoxical psoriasis in a large cohort of patients with inflammatory bowel disease receiving treatment with anti-TNF alpha: 5-year follow-up study

BACKGROUND

Psoriasis is an emerging paradoxical side effect in patients with inflammatory bowel disease (IBD) when treated with anti-TNF alpha. Patients with severe skin lesions unresponsive to topical therapy need to withdraw from treatment.

AIM

To estimate the incidence of paradoxical psoriasis in a large cohort of IBD patients treated with anti-TNF alpha and to analyse its clinical correlates.

METHODS

A retrospective cohort study on all IBD patients who started anti-TNF alpha at our IBD Centre from January 2008 to December 2013 was performed. Proportional hazards regression models were used to estimate the association between each predictor and time to the development of psoriasis. Time-dependent predictors were updated at each available time point.

RESULTS

Four hundred and two patients were included. Participants contributed a total of 839 person-years of follow-up, during which 42 incident cases of psoriasis were recorded, with an incidence rate of five per 100 person-years. Cox-regression survival analysis revealed smoking as independent predictor of psoriasis (HR: 2.37, 95% CI: 1.36-4.48; P = 0.008). Conversely, concomitant immunosuppressive therapy was inversely related to psoriasis (HR: 0.33, 95% CI: 0.12-0.92; P = 0.03).

CONCLUSIONS

Paradoxical psoriasis is a relevant side effect of anti-TNF alpha therapy, with an incidence rate of five per 100 person-years. Smoking is confirmed as the main risk factor for developing lesions. The combination therapy with anti-TNF alpha plus immunosuppressants is associated with a reduced risk of paradoxical psoriasis.

Development of psoriasis scalp with alopecia during treatment of Crohn's disease with infliximab and rapid response to both diseases to ustekinumab

Anti tumor necrosis factor antibodies are used to treat both psoriasis and inflammatory bowel disease. Several paradoxical cases of psoriatic skin lesions induced by tumor necrosis factor antagonist therapy have been described in IBD patients in the recent years. Ustekinumab, a fully human anti-interleukin-12/-23 monoclonal antibody, is the first drug of a new class of biologic therapy approved for the treatment of moderate to severe plaque psoriasis. Data on the efficacy of ustekinumab in patients with moderate-to-severe Crohn's disease, especially in patients previously treated with infliximab, have been recently published. We report about the effectiveness of ustekinumab in the treatment of both severe scalp psoriasis lesions with alopecia and active Crohn's disease.

[Clinical practice guideline on the management of patients with dyspepsia. Update 2012]

The aim of the Clinical Practice Guideline (CPG) on the Management of Patients with Dyspepsia is to generate recommendations on the optimal approach to dyspepsia in the primary care and specialized outpatient setting. The main objective of this CPG is to help to optimize the diagnostic process, identifying patients with a low risk of a serious organic disease (mainly tumoral), who could be safely managed without the need for invasive diagnostic tests and/or referral to a specialist. The importance of this aim lies in the need to accurately diagnose patients with esophagogastric cancer and correctly treat peptic ulcer while, at the same time, reduce negative endoscopies in order to appropriately use the available healthcare resources. This CPG reviews the initial strategies that can be used in patients with uninvestigated dyspepsia and evaluates the possible decision to begin empirical therapy or to investigate the existence of a lesion that could explain the symptoms. This CPG also discusses functional dyspepsia, which encompasses all patients with dyspepsia with no demonstrable cause on endoscopy. Recommendations for the diagnosis and treatment of peptic ulcer and Helicobacter pylori infection are also made. To classify the scientific evidence and strengthen the recommendations, the GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) system has been used (http://www.gradeworkinggroup.org/).

A cross-sectional study of the appropriateness of colonoscopy requests in the Spanish region of Catalonia

INTRODUCTION

Colonoscopies are being requested with increasing frequency in the last few years, as they are used both as a diagnostic and therapeutic procedure in several gastrointestinal diseases. Our purpose is to describe the appropriateness of colonoscopy requests issued both from primary care centres and from hospitals, according to the EPAGE II guidelines (European Panel on the Appropriateness of Gastrointestinal Endoscopy).

METHODS AND ANALYSIS

Cross-sectional study. Colonoscopy requests issued since January 2011 and received at the endoscopy units of all six reference hospitals serving the primary care centres of the South Metropolitan and Central Catalonia districts will be collected (total=1500 requests). Variables to be collected include gender, date of birth, origin of the request and reference hospital, priority of the procedure, type of clinician requesting the procedure, date and indication of request, abdominal examination performed, anal inspection examination performed, date of last colonoscopy if applicable, diagnosis and date of diagnosis. Using the available information and the EPAGE II website, colonoscopy requests will be assigned as an appropriateness score. The association between the variables collected and the EPAGE II scores will be assessed using a Student's t test and a χ(2) test. A multilevel logistic model will be generated on the factors associated with the appropriateness of the requests.

ETHICS AND DISSEMINATION

Colonoscopy is a costly procedure and not free from complications. In order to increase cost effectiveness, reduce waiting lists and optimise resources, it is necessary to use tools such as the EPAGE II guidelines, which establish criteria to assess the appropriateness of colonoscopies. The purpose of this study is to describe the current situation and to discuss whether current clinical practice is appropriate. The results of the study will be published in the next few years. In consideration of the ethical principles and methods of the research study, approval was granted for the project.

Knowledge and attitudes of primary healthcare patients regarding population-based screening for colorectal cancer

Background

The aim of this study was to assess the extent of knowledge of primary health care (PHC) patients about colorectal cancer (CRC), their attitudes toward population-based screening for this disease and gender differences in these respects.

Methods

A questionnaire-based survey of PHC patients in the Balearic Islands and some districts of the metropolitan area of Barcelona was conducted. Individuals between 50 and 69 years of age with no history of CRC were interviewed at their PHC centers.

Results

We analyzed the results of 625 questionnaires, 58% of which were completed by women. Most patients believed that cancer diagnosis before symptom onset improved the chance of survival. More women than men knew the main symptoms of CRC. A total of 88.8% of patients reported that they would perform the fecal occult blood test (FOBT) for CRC screening if so requested by PHC doctors or nurses. If the FOBT was positive and a colonoscopy was offered, 84.9% of participants indicated that they would undergo the procedure, and no significant difference by gender was apparent. Fear of having cancer was the main reason for performance of an FOBT, and also for not performing the FOBT, especially in women. Fear of pain was the main reason for not wishing to undergo colonoscopy. Factors associated with reluctance to perform the FOBT were: (i) the idea that that many forms of cancer can be prevented by exercise and, (ii) a reluctance to undergo colonoscopy if an FOBT was positive. Factors associated with reluctance to undergo colonoscopy were: (i) residence in Barcelona, (ii) ignorance of the fact that early diagnosis of CRC is associated with better prognosis, (iii) no previous history of colonoscopy, and (iv) no intention to perform the FOBT for CRC screening.

Conclusion

We identified gaps in knowledge about CRC and prevention thereof in PHC patients from the Balearic Islands and the Barcelona region of Spain. If fears about CRC screening, and CRC per se, are addressed, and if it is emphasized that CRC is preventable, participation in CRC screening programs may improve.

New biological agents for the treatment of the "high risk" IBD patients

BACKGROUND

Several new biological drugs have been introduced in the last decade or are under investigation for the treatment of IBD. They include anti TNFalpha agents, anti adhesion molecules, anti IL-12/23, anti IL-6R and others. Their role in IBD therapy will be discussed in regard of the association of chronic inflammation and cancer in the gut. The risk of colorectal cancer is increased in ulcerative colitis (UC) and, to some extent, in Crohn's disease (CD). This association is well known from many years. However, the mechanisms linking chronic inflammation and carcinogenesis are beginning to be elucidated only recently.

RESULTS AND CONCLUSIONS

Experimental data indicate that several cytokines could play a role in promoting tumour development. In this perspective, the anti cytokine agents could be not only powerful tools in treating inflammation but also efficacious in preventing the onset of inflammation associated colorectal cancer.

Combined therapy with infliximab and seton drainage for perianal fistulizing Crohn's disease with anal endosonographic monitoring: a single-centre experience

During infliximab treatment of perianal Crohn's disease (CD), the healing of the skin opening precedes fistula tract healing and this contributes to abscess formation and fistula recurrence. The aims of this study were to evaluate the efficacy of combined treatment with infliximab and setons for complex perianal fistulas in CD and to define the optimal time for seton removal by anal endosonography (AE). Nine consecutive patients with CD were studied. Perianal sepsis was eradicated when necessary and setons were placed before infliximab therapy. Setons were removed after AE evidence of fistulous tracts healing. Patients received a mean of 10+/-2.3 infliximab infusions. At week 6 all patients showed a reduction in mean CD activity index (p<0.005) and perianal disease activity index (p<0.0001). Complete fistula response was achieved in eight of nine patients. In six patients after a mean of 9.2 infusions, infliximab treatment was discontinued. Clinical and AE response persisted at 19.4+/-8.8 months (range 3-28 months) in five of these patients. One patient had fistula recurrence 20 weeks after infliximab discontinuation and responded rapidly to retreatment. At the time of this report, two patients were still on infliximab and in remission after a mean follow-up of 25+/-5 months. Combined therapy with infliximab and setons with AE monitoring of the response showed high efficacy in the management of patients with CD with complex perianal fistulas.

Length of follow-up after fistulotomy and fistulectomy associated with endorectal advancement flap repair for fistula in ano

BACKGROUND

The length of follow-up required after surgical repair of cryptoglandular fistula in ano has not been established. This prospective study determined the follow-up time needed to establish that an anal fistula has been cured after elective fistulotomy or fistulectomy associated with endorectal advancement flap (ERAF) repair.

METHODS

Between January 2001 and June 2004, consecutive patients with anal fistula of cryptoglandular aetiology were included provided that they lived within the catchment area of the hospital and agreed to participate in a follow-up programme, which comprised scheduled visits every month until complete wound healing and annually thereafter.

RESULTS

Some 206 of 219 eligible patients were evaluable; fistulotomy was performed in 115 and ERAF repair in 91. Median follow-up was 42 (range 24-65) months. Eighteen patients had recurrence of the fistula during follow-up, with a median time to relapse of 5.0 (range 1.0-11.7) months. There were no recurrences after 1 year.

CONCLUSION

Recurrence of fistula in ano of cryptoglandular origin treated by means of fistulotomy or ERAF repair occurs within the first year of operation.

Single agent versus combination chemotherapy for metastatic breast cancer

BACKGROUND

It is commonly thought that combining chemotherapy agents for treating women with metastatic breast cancer will result in regimens that are more active, offer superior tumour response rates with more time before progression and improve overall survival. However, it is not known whether giving patients more intensive chemotherapy regimens (judged according to some measure eg dose, dose intensity, response rate, or toxicity) results in better health outcomes. One way to investigate the effect of more versus less-intensive chemotherapy is to compare regimens containing a single drug (and hence possibly less active treatment) with regimens containing a greater number of drugs (and hence possibly more active but more toxic), even when adjustments are made to dosages or schedules to account for toxicity.

OBJECTIVES

To compare use of single chemotherapy agents with regimens containing a combination of agents for the treatment of metastatic breast cancer.

SEARCH STRATEGY

The Specialised Register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 2nd May 2003 using the codes for "advanced breast cancer", "chemotherapy". Details of the search strategy applied by the group to create the register, and the procedure used to code references, are described in the group's module on The Cochrane Library.

SELECTION CRITERIA

Randomised trials comparing single agent chemotherapy with combination therapy in women with metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from published trials. Studies were assessed for eligibility and quality, and data were extracted by two independent reviewers. Hazard ratios were derived for time-to-event outcomes where possible, and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present.

MAIN RESULTS

Thirty seven eligible trials were identified of which 28 had published time-to-event data. The quality of randomisation was generally not described. Data, based on an estimated 4220 deaths in 5707 women, show a modest advantage for combination chemotherapy regimens compared with single agents with a hazard ratio (HR) for overall survival of 0.88 (95% CI=0.83-0.94, P<0.0001) and no evident heterogeneity. Results are similar if the analysis is limited to trials in women receiving first-line chemotherapy. Combination regimens are favourably associated with time to progression (overall HR of 0.78 (95% CI=0.73-0.83, P<0.00001) and tumour response rates (OR 1.28, CI=1.15-1.42, P<0.00001) although significant heterogeneity was observed (P=0.002 and P<0.00001 respectively). This probably reflects the varying efficacy of the comparator regimens used in the trials. Women receiving combination regimens experienced a higher toxicity level for leukopenia, hair loss and nausea and vomiting compared with those receiving a single agent, which was statistically significant.

AUTHORS' CONCLUSIONS

Compared with single-chemotherapy agents, combination regimens show a statistically significant advantage for tumor response and time to progression in women with metastatic breast cancer, a modest improvement in overall survival and significantly worse toxicities.

Strategies for increasing women participation in community breast cancer screening

BACKGROUND

Strategies for reducing breast cancer mortality in western countries have focused on screening, at least for women aged 50 to 69 years. One of the requirements of any community screening program is to achieve a high participation rate, which is related to methods of invitation. Therefore, it was decided to systematically review the scientific evidence on the different strategies aimed at improving women's participation in breast cancer screening programs and activities.

OBJECTIVES

To assess the effectiveness of different strategies for increasing the participation rate of women invited to community (population-based) breast cancer screening activities or mammography programs.

SEARCH STRATEGY

MEDLINE (1966-2000), CENTRAL (2000), and EMBASE (1998-1999) searches for 1966 to 1999 were supplemented by reports and letters to the European Screening Breast Cancer Programs (Euref Network).

SELECTION CRITERIA

Both published and unpublished trials were eligible for inclusion, provided the women had been invited to a community breast screening activity or program and had been randomised to an intervention group or a control group with no active intervention.

DATA COLLECTION AND ANALYSIS

We identified 151 articles, which were reviewed independently by two people. The discrepancies were resolved by a third reviewer in order to reach consensus. Thirty-four studies were excluded because they lacked a control group; 58 of the other 117 articles were considered as opportunistic and not community-based; 59 articles, which reported 70 community-based randomised controlled trials or clinical controlled trials, were accepted. In 24 of these, the control group had not been exposed to any active intervention, but 8 of the 24 had to be excluded because the denominator for estimating attendance was unknown. At the end, 16 studies constituted the material for this review, although two studies were further excluded because their groups were not comparable at baseline. Data from all but one study were based on or converted to an intention-to-treat analysis. Attendance in response to the mammogram invitation was the main outcome measure.

MAIN RESULTS

The evidence favoured five active strategies for inviting women into community breast cancer screening services: letter of invitation (OR 1.66, 95% CI 1.43 to 1.92), mailed educational material (OR 2.81, 95% CI 1.96 to 4.02), letter of invitation plus phone call (OR 2.53, 95% CI 2.02 to 3.18), phone call (OR 1.94, 95% CI 1.70 to 2.23), and training activities plus direct reminders for the women (OR 2.46, 95% CI 1.72 to 3.50). Home visits did not prove to be effective (OR 1.06, 95 % CI 0.80 to 1.40) and letters of invitation to multiple examinations plus educational material favoured the control group (OR 0.62, 95 % CI 0.32 to 1.20).

REVIEWER'S CONCLUSIONS

Most active recruitment strategies for breast cancer screening programs examined in this review were more effective than no intervention. Combinations of effective interventions can have an important effect. Some costly strategies, as a home visit and a letter of invitation to multiple screening examinations plus educational material, were not effective. Further reviews comparing the effective interventions and studies that include cost-effectiveness, women's satisfaction and equity issues are needed.

[Adenocarcinoma of the ceruminous glands: report of three cases]

We report three cases of ceruminoma seen in our department over a 1-year period and review the neoplasms of the ceruminous glands. According to the Welti classification, our three cases were ceruminous adenocarcinomas. Based on existing literature, ceruminous adenocarcinoma is the least frequent neoplasm of the ceruminous glands.

[An epidemic outbreak of measles in a rural area]

OBJECTIVE

Analysis of an outbreak of measles among a partially vaccinated school population: the epidemiology, the effectiveness of the control measures and the efficacy of the vaccine (EV).

DESIGN

A descriptive study and cohorts study.

SETTING

Primary Care in the borough of Sant Andreu de la Barca.

PATIENTS AND OTHERS PARTICIPANTS

The school population of Sant Andreu de la Barca.

MEASUREMENTS AND MAIN RESULTS

The outbreak lasted three months and twenty days, with 95 cases overall. The most affected age group was form 4 to 10. 8.4% presented complications. Children were infected at school in 87% of the cases. The overall infection rate of the population between 0 and 15 was 2.4%. 36% of the cases had been correctly immunized and 43% were preventable cases. Vaccine coverage contacts was 67%. 84% of the susceptible contacts were vaccinated. Immunization status and immunization age of 323 out of 500 pupils was studied for the EX analysis. Global EV was 66% (42-80), 58% (13-80) for those immunized, between 12-14 month of age and 71% (43-85) for those immunized after the 15 month of age.

CONCLUSIONS

In order to eradicate the autoctonous measles an increase in immunization coverage, an improvement in the epidemiologic surveillance, and in the outbreak control measures are needed.

[The optimization of the data base of a voluntary health care cooperative for the study of postoperative morbidity in benign prostatic hypertrophy]

BACKGROUND

Investigation in health care services by data bases (DB) is undergoing an important increase in numerous countries. Several of the most relevant epidemiologic studies on the postsurgical morbidity and mortality of benign hypertrophy of the prostate (BHP) have used DB. The aim of this study was to prepare and optimize the DB of a health cooperative (Asistencia Sanitaria Colegial).

METHODS

Since 1981 the DB contains sociodemographic variables, data concerning visits to general practitioners and specialists, complementary examinations and hospitalizations. The coding system was specifically developed by the cooperative. The study base was made up of all the policies of the members between January 1981 and December 1988 (101,400 males). To identify the policies 14 codes potentially related with BHP were initially chosen and all the policies containing any of these codes were selected, with the manual analysis of 204 policies being thereby performed.

RESULTS

The total number of policies initially selected for the study was 3,157. Manual revision discarded the use of 9 of the 14 codes used in the first selection. In agreement with the 5 codes able to define diseases of prostatic gland and to the file in which they appeared the policies were classified as probable diseases of prostatic gland (n = 1,007, 31.9%), possible (n = 805, 25.5%) and improbable (n = 1,345, 42.5%). Likewise, the strategy to follow for the selection of a cohort of BHP cases was defined.

CONCLUSIONS

The manual analysis of policies evidenced a remarkable coherence and exhaustiveness of the information registered. The principal difficulties found with the data base used were the lack of a sole diagnosis and the coding system used in addition to the impossibility of automatically controlling the assistance received by the patients outside the cooperative system. The availability of a data base such as that herein described with a well defined large population and with accessible sociodemographic and health care information justifies collaborative efforts among health care administrators, clinicians, computer scientists and epidemiologists.

Chemical modification studies of beef-heart mitochondrial b-c1 complex. Effect of modification by ethoxyformic anhydride

The effect of the histidine-modifier ethoxyformic anhydride (EFA) on the enzymatic properties of the mitochondrial b-c1 complex (ubiquinol-cytochrome c reductase) has been investigated. Chemical modification by EFA inhibited to the same extent the reductase and the proton translocating activity of the complex. In particular EFA modification of the complex resulted in: strong inhibition of the antimycin-insensitive reduction of b cytochromes; inhibition of the antimycin-promoted oxidant-induced reduction of b cytochromes and inhibition of oxidation of pre-reduced b cytochromes. Analysis of the absorbance at 238 nm, indicative of N-(ethoxyformyl)histidine derivative, of the various polypeptide subunits separated by high-pressure liquid chromatography procedure, showed that EFA modified residues in core proteins and in the low-molecular-mass proteins. Both the inhibition of the redox and the protonmotive activity of the complex and the absorbance increase at 238 nm of the core protein fraction were readily reversed by hydroxylamine, indicating that modification of histidine residue(s) in core protein(s) is critical for the activity of the complex. This was supported by the finding that modification of the reductase with EFA prevented binding of fluorescein isothiocyanate to histidine residue(s) in core protein II. EFA modification of the reductase was without effect on the binding of N-(7-dimethylamino-4-methylcoumarinyl)maleimide to the various polypeptides of the complex except for the binding to the Fe-S protein which was greatly potentiated. Thus primary chemical modification of histidine residue(s) in core protein (II) appears to cause, in turn, a conformational change in the Rieske Fe-S protein.

Effect of 2,4-dinitrofluorobenzene on the enzymatic properties of the b-c1 complex isolated from beef heart mitochondria

A study is presented on the effect of 2,4-dinitrofluorobenzene (DFNB) on the enzymatic properties of mitochondrial b-c1 complex. The chemical modification by DNFB strongly inhibits the reductase activity of the complex, this being accompanied by labelling by [3H]DNFB of core protein I, the apoprotein of b cytochromes and the 12 kDa subunit. Chemical modification by DNFB appears to alter, in particular, the domain of heme b-562.

Effect of papain digestion on redox-linked proton translocation in b-c1 complex from beef heart reconstituted into liposomes

Papain treatment of the cytochrome b-c1 complex from beef heart results in partial proteolysis of core protein II, the iron-sulphur protein and the 15-kDa subunit. Under these conditions a significant inhibition of electron flow and complete suppression of proton translocation in the complex reconstituted into liposomes are observed. Kinetic experiments indicate a correlation between the digestion of core protein II and 15-kDa subunit and the suppression of proton translocation. The results suggest an active involvement of polypeptides of the complex in stabilizing the semiquinone species and/or providing pathways to exchange protons between bound quinone systems and aqueous phases.