Infections in intensive care unit adult patients harboring multidrug-resistant Pseudomonas aeruginosa: implications for prevention and therapy.

The purpose of this paper was to report the burden and characteristics of infection by multidrug-resistant Pseudomonas aeruginosa (MDR-PA) in clinical samples from intensive care unit (ICU) adults, and to identify predictors. This was a retrospective observational study at four medical-surgical ICUs. The case cohort comprised adults with documented isolation of an MDR-PA strain from a clinical specimen during ICU stay. Multivariate analysis was performed to identify predictors for MDR-PA infection. During the study period, 5667 patients were admitted to the ICU and P. aeruginosa was isolated in 504 (8.8%). MDR-PA was identified in 142 clinical samples from 104 patients (20.6%); 62 (43.6%) of these samples appeared to be true infections. One hundred and eighteen (83.1%) isolates were susceptible only to amikacin and colistin, and 13 (9.2%) were susceptible only to colistin. Overall, the MIC50 to meropenem was 16 µg/mL and the MIC90 was >32 µg/mL, with 60.4% of respiratory samples being MIC >32 µg/mL to meropenem. Independent predictors for MDR-PA infection were fever/hypothermia [odds ratio (OR) 9.09], recent antipseudomonal cephalosporin therapy (OR 6.31), vasopressors at infection onset (OR 4.40), and PIRO (predisposition, infection, response, and organ dysfunction) score >2 (OR 2.06). This study provides novel information that may be of use for the clinical management of patients harboring MDR-PA and for the control of the spread of this organism.

The clinical significance of pneumonia in patients with respiratory specimens harbouring multidrug-resistant Pseudomonas aeruginosa: a 5-year retrospective study following 5667 patients in four general ICUs.

Pseudomonas aeruginosa is the leading cause of pneumonia in intensive care units (ICUs), with multidrug-resistant (MDR) strains posing a serious threat. The aim of this study was to assess the clinical relevance of MDR Pseudomonas isolates in respiratory clinical specimens. A 5-year retrospective observational study in four medical-surgical ICUs from a referral hospital was carried out. Of 5667 adults admitted to the ICU, 69 had MDR-PA in respiratory samples: 31 were identified as having pneumonia (HAP/VAP): 21 ventilator-associated pneumonia (VAP) and ten hospital-acquired pneumonia (HAP). Twenty-one (67.7%) adults with MDR-PA HAP/VAP died after a median of 4 days (18 of the 21 deaths within 8 days), compared with one (2.6%) without pneumonia at day 8. In a Cox proportional regression model, MDR-PA pneumonia was an independent variable [adjusted hazard ratio (aHR) 5.92] associated with 30-day ICU mortality. Most strains (85.1%) were susceptible to amikacin and colistin. Resistance to beta-lactams (third-generation cephalosporins and piperacillin-tazobactam) ranged from 44.1% to 45.3%. Meropenem showed poor overall activity (MIC[50/90] 16/32 mg/dL), with 47.0% having a minimum inhibitory concentration (MIC) breakpoint >8 mg/L. Twenty-four (77.4%) HAP/VAP episodes received inappropriate empirical therapy. Although empirical combination therapy was associated with less inappropriate therapy than monotherapy (16.7% vs. 88.3%, p < 0.01), there was no difference in survival (30% vs. 33.3%, p = 0.8). Pneumonia was identified in one-third of adult ICU patients harbouring MDR-PA in respiratory clinical specimens. These patients have a 6-fold risk of (early) death compared to ventilator-associated tracheobronchitis (VAT) and respiratory colonisation. New antibiotics and adjuvant therapies are urgently needed to prevent and treat MDR-PA HAP/VAP.

Long-term allergic dermatitis caused by sevoflurane: a clinical report.

BACKGROUND: Allergy to volatile anaesthetics is extremely rare, but capable of damaging the professional career. METHODS: This article presents the case of a 60-year-old surgeon who developed a skin rash on the reverse of hands, which progressively worsened and extended to distant fold areas. Blood tests were normal but for eosinophilia and risen total IgE, with normal specific globulins and skin prick tests for common allergens. After 8 years, a malfunction in the anaesthetic gas scavenging system was found, and symptoms remitted within a week following its replacement. Repeated open application test with sevoflurane led to the appearance of the same lesions in the tested areas and in distant body folds. RESULTS: We hypothesize that the most probable mechanism for the reaction in our patient is systemic allergic contact dermatitis, which is caused by repeated systemic exposure to a hapten that reaches the skin through haematogenous transport in a sensitized patient. CONCLUSIONS: The report aims to warn about the potential aetiological relationship between exposure to inhaled anaesthetics and allergic manifestations with cutaneous symptoms.

[Translated article] Preoperative assessment and surgical indications: Separation surgery.

Neurological compression occurs in 10%-20% of patients who develop spinal metastases. In the last decade, the evolution of oncological diagnostic and medical techniques, the change from conventional external radiation to radiosurgery and the new surgical instruments have meant that the treatment of these patients must be indicated in a personalized manner and by consensus, multidisciplinary way, in specific commissions. Today, the biological state of the patient, the presence of mechanical instability, the neurological assessment and degree of epidural compression, as well as the best prognostic categorization of the tumor, are established as decision factors prior to the indication of surgical treatment, treatment that has passed from a cytoreductive concept to that of a spinal cord release from tumor in order to ensure safe radiosurgery.

Preoperative assessment and surgical indications: Separation surgery. / Valoración e indicaciones quirúrgicas: cirugía separación.

Neurological compression occurs in 10%-20% of patients who develop spinal metastases. In the last decade, the evolution of oncological diagnostic and medical techniques, the change from conventional external radiation to radiosurgery and the new surgical instruments have meant that the treatment of these patients must be indicated in a personalized manner and by consensus, multidisciplinary way, in specific commissions. Today, the biological state of the patient, the presence of mechanical instability, the neurological assessment and degree of epidural compression, as well as the best prognostic categorization of the tumor, are established as decision factors prior to the indication of surgical treatment, treatment that has passed from a cytoreductive concept to that of a spinal cord release from tumor in order to ensure safe radiosurgery.

[Gonococcal pelviperitonitis: a diagnostic challenge].

Neisseria gonorrhoeae is the second most common etiological agent of pelvic inflammatory disease and is currently un-derdiagnosed due to its asymptomatic presentation in 50% of cases. When the disease presents, it may appear in the form of acute abdomen and normal imaging tests, making it a major diagnostic challenge. We present four cases of acute gonococcal peritonitis. The main symptom was acute abdominal pain, and both the gy-necological examination and complementary tests showed normal results. The only notable finding from the laparoscopy was the existence of purulent ascitic fluid. The results of the anatomical and pathological tests were all normal. Endocer-vical and ascitic fluid culture showed infection with N. gonorrhoeae, and in one case, concomitant infection with Chlamydia trachomatis. The definitive treatment applied was intravenous antibiotic therapy. When a sexually active young woman is diagnosed with peritonitis that has no apparent cause, it is important to rule out sexually transmitted diseases.

Summary of recommendations and key points of the consensus of Spanish scientific societies (SEPAR, SEMICYUC, SEMES; SECIP, SENEO, SEDAR, SENP) on the use of non-invasive ventilation and high-flow oxygen therapy with nasal cannulas in adult, pediatric, and neonatal patients with severe acute respiratory failure. / Sumario de las recomendaciones y puntos clave del Consenso de las Sociedades Científicas Españolas (SEPAR, SEMICYUC, SEMES; SECIP, SENeo, SEDAR, SENP) para la utilización de la ventilación no invasiva y terapia de alto flujo con cánulas nasales en el paciente adulto, pediátrico y neonatal con insuficiencia respiratoria aguda grave.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.

Summary of recommendations and key points of the consensus of Spanish scientific societies (SEPAR, SEMICYUC, SEMES; SECIP, SENEO, SEDAR, SENP) on the use of non-invasive ventilation and high-flow oxygen therapy with nasal cannulas in adult, pediatric, and neonatal patients with severe acute respiratory failure.

Non-invasive respiratory support (NIRS) in adult, pediatric, and neonatal patients with acute respiratory failure (ARF) comprises two treatment modalities, non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC) therapy. However, experts from different specialties disagree on the benefit of these techniques in different clinical settings. The objective of this consensus was to develop a series of good clinical practice recommendations for the application of non-invasive support in patients with ARF, endorsed by all scientific societies involved in the management of adult and pediatric/neonatal patients with ARF. To this end, the different societies involved were contacted, and they in turn appointed a group of 26 professionals with sufficient experience in the use of these techniques. Three face-to-face meetings were held to agree on recommendations (up to a total of 71) based on a literature review and the latest evidence associated with 3 categories: indications, monitoring and follow-up of NIRS. Finally, the experts from each scientific society involved voted telematically on each of the recommendations. To classify the degree of agreement, an analogue classification system was chosen that was easy and intuitive to use and that clearly stated whether the each NIRS intervention should be applied, could be applied, or should not be applied.

Influence of pneumococcal serotype group on outcome in adults with bacteraemic pneumonia.

The influence of infecting serotype group on outcome in bacteraemic pneumococcal pneumonia remains unclear. We performed a prospective, 10-yr observational study in an 800-bed teaching hospital. 299 adults diagnosed with pneumonia whose blood cultures showed growth of Streptococcus pneumoniae were included in the study. High invasive disease potential (H) serotypes included serotypes 1, 5 and 7F, which served as a reference category, were compared with low invasive disease potential (L) serotypes (3, 6A, 6B, 8, 19F, and 23F) and other (O) serotypes (non-H, non-L). The influence on outcome was determined for each group of serotypes after adjusting for underlying conditions and severity of illness at admission. Overall, 30-day mortality was 11%. H serotypes (n = 93) infected primarily younger people and presented a higher risk of complicated parapneumonic effusion or empyema (17.2 versus 5.1%; p = 0.01), with lower mortality (3.2%). The isolation of L serotypes (n = 78) was an independent risk factor for 30-day mortality (OR 7.02, 95% CI 1.72-28.61), as were Charlson score (OR 1.30, 95% CI 1.08-1.58), alcohol abuse (OR 3.99, 95% CI 1.39-11.39) and severity of illness measured by American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) criteria (OR 4.80, 95% CI 1.89-12.13). A vaccination strategy including serotypes 3, 6A, 6B, 8, 19F and 23F may improve survival in adults.

Development of morphologically dominant follicles is associated with fewer metabolic disturbances in amenorrheic women with polycystic ovary syndrome: a pilot study.

OBJECTIVES: To determine if amenorrheic women with polycystic ovary syndrome (PCOS) demonstrate ultrasonographically detectable changes in follicle population. METHODS: Sixteen women with PCOS reporting the absence of menses for more than 3 months were enrolled in the study. Subjects had a physical examination, fasting blood tests and two transvaginal ultrasound scans spaced 1 month apart. In cases where evidence of a morphologically dominant follicle (≥ 10 mm in diameter) occurred, subsequent ultrasound scans were performed to determine the fate of the dominant follicle. Differences in total follicle population, maximum follicle diameter and clinical, hormonal and metabolic features were determined. RESULTS: Forty-four percent of subjects showed changes in follicle population of 6-10 follicles and 37% showed changes in follicle population of > 10. Maximum follicle diameters ranged between 5.4 and 33.0 mm. Four subjects demonstrated follicle diameters ≥ 10 mm. Of those who developed dominant follicles, two subjects ovulated, one subject developed a persistent anovulatory follicle and the dominant follicle regressed in the remaining subject. Diagnostic criteria for PCOS were similar among women that did or did not develop dominant follicles (menstrual cycle length, P = 0.880; hirsutism score, P = 0.809; free androgen index, P = 0.991; total follicle count, P = 0.199). However, lower glycosylated hemoglobin (P = 0.047) and insulin levels (P = 0.049) and better insulin sensitivity (P = 0.048) were noted in women who attained dominant follicles. CONCLUSION: Amenorrheic women with PCOS demonstrate changes in follicle population that are consistent with active follicle growth and regression despite prolonged periods of anovulation. Morphologic selection occurs in amenorrheic women and attainment of dominant follicles is associated with improved metabolic status.

Endoscopic pneumatic balloon dilation in primary achalasia: predictive factors, complications, and long-term follow-up.

Pneumatic dilation (PD) has been widely used in the treatment of idiopathic achalasia with a 70-90% response. The aim of this study was to evaluate the effectiveness of PD and its predictive factors by means of clinical assessment. In addition, we evaluated its safety and the need for subsequent surgical intervention. Fifty-six patients were treated with a Witzel dilator. The response was evaluated at medium (1-5 years) and long term (>5 years). Diverse possible predictive factors to response were analyzed. After the first PD, 85.7% of the 56 patients improved and passed from clinical stage II-III to clinical stage 0-I (P < 0.005). After the second dilation, 84.6% of the patients (13) passed to clinical stage 0-I (P < 0.05). Only patients who were not young (>40 years) avoided a second dilation and/or surgery (P < 0.001). During the first 5 years of follow-up, 80% of patients maintained their response; this percentage decreased to 58% after 10 years. PD therapy of achalasia is a safe technique, with few adverse effects (4% perforations and 10% gastroesophageal reflux). It offers a medium-term response of 80% and long-term response of around 60%. Age was the only predictive response factor.

Optimal predictive control of water transport systems: Arrêt-Darré/Arros case study.

This paper proposes the use of predictive optimal control as a suitable methodology to manage efficiently transport water networks. The predictive optimal controller is implemented using MPC control techniques. The Arrêt-Darré/Arros dam-river system located in the Southwest region of France is proposed as case study. A high-fidelity dynamic simulator based on the full Saint-Venant equations and able to reproduce this system is developed in MATLAB/SIMULINK to validate the performance of the developed predictive optimal control system. The control objective in the Arrêt-Darré/Arros dam-river system is to guarantee an ecological flow rate at a control point downstream of the Arrêt-Darré dam by controlling the outflow of this dam in spite of the unmeasured disturbances introduced by rainfalls incomings and farmer withdrawals.

Endoscopic Treatment for Vesicoureteral Reflux in Recurrent Urinary Tract Infections in Kidney Transplant: Experience of One Center.

Vesicoureteral reflux (VUR) after renal transplantation in adult patients has been reported. In renal transplant recipients, symptomatic urinary tract infection can cause high morbidity despite improved immunosuppressive and antibiotic treatment. In our country there have been few reported cases about use of copolymer of dextranomer and hyaluronic acid (DX-HA) injection in a renal transplant. We present 3 cases of recurrent or complicated infections with evidence of high-grade VUR, which were treated with DX-HA. Only 1 case had a partial remission; however, there were no episodes of urinary tract infection in 12 months of follow-up. Suburethral injection is an endoscopic treatment modality with low morbidity in our country.

[Monitoring of oxygen pressure in brain tissue in severely injured patients under neurocritical care]. / Monitorización de la presión tisular cerebral de oxígeno en el paciente neurocrítico.

Head injury continues to be the main cause of mortality and morbidity among young people in Europe. The use of technology in managing severe head injury has increased considerably and certain applications may be confusing to physicians who have little experience in neurology but who are charged with providing neurocritical care. Monitoring of brain-injured patients usually focuses on managing intracranial pressure and recording perfusion pressure. New techniques have recently been incorporated into routine monitoring of oxygenation and metabolism in the brain. Continuous monitoring of the partial oxygen pressure of brain tissue (PtO2) has become more common in neurocritical care units, making bedside evaluation of the effects of injuries and therapeutic measures possible. This review discusses technical, safety, and reliability aspects of PtO2 monitoring and its potential advantages in comparison with other techniques for evaluating brain tissue oxygenation.

Exposure of adolescent mice to 3,4-methylenedioxypyrovalerone increases the psychostimulant, rewarding and reinforcing effects of cocaine in adulthood.

BACKGROUND AND PURPOSE: 3,4-Methylenedioxypyrovalerone (MDPV) is a synthetic cathinone with powerful psychostimulant effects. It selectively inhibits the dopamine transporter (DAT) and is 10-50-fold more potent as a DAT blocker than cocaine, suggesting a high abuse liability. The main objective of the present study was to assess the consequences of an early (adolescence) MDPV exposure on the psychostimulant, rewarding and reinforcing effects induced by cocaine in adult mice. EXPERIMENTAL APPROACH: Twenty-one days after MDPV pretreatment (1.5 mg·kg-1 , s.c., twice daily for 7 days), adult mice were tested with cocaine, using locomotor activity, conditioned place preference and self-administration (SA) paradigms. In parallel, dopamine D2 receptor density and the expression of c-Fos and ΔFosB in the striatum were determined. KEY RESULTS: MDPV treatment enhanced the psychostimulant and conditioning effects of cocaine. Acquisition of cocaine SA was unchanged in mice pretreated with MDPV, whereas the breaking point achieved under a progressive ratio programme and reinstatement after extinction were higher in this group of mice. MDPV decreased D2 receptor density but increased ΔFosB expression three-fold. As expected, acute cocaine increased c-Fos expression, but MDPV pretreatment negatively influenced its expression. ΔFosB accumulation declined during MDPV withdrawal, although it remained elevated in adult mice when tested for cocaine effects. CONCLUSION AND IMPLICATIONS: MDPV exposure during adolescence induced long-lasting adaptive changes related to enhanced responsiveness to cocaine in the adult mice that seems to lead to a higher vulnerability to cocaine abuse. This particular behaviour correlated with increased expression of ΔFosB.

[Transcutaneous measurement of partial pressure of carbon dioxide and oxygen saturation: validation of the SenTec monitor]. / Medición transcutánea de la presión parcial de anhídrido carbónico y de la saturación de oxígeno: validación del monitor SenTec.

OBJECTIVE: To validate a monitor for transcutaneous measurement of oxygen saturation (SpO2) and partial pressure of carbon dioxide (TcPCO2). PATIENTS AND METHODS: This observational study included 140 Caucasian nonsmokers without jaundice. Patients underwent forced spirometry, measurement of SpO2 and TcPCO2 with the SenTec monitor, and arterial blood gas analysis (readings with 2 devices) during the stabilization phase of the monitor. In the statistical analysis, values from the 2 devices for measuring arterial blood gases were compared by mean differences for PaCO2 and oxygen saturation (SaO2). The arithmetic mean of the 2 blood gas measurements was calculated and relations between them and the SpO2 and TcPCO2 were assessed by the Pearson correlation coefficient (r) and the intraclass correlation coefficient (ICC) as a measure of agreement. Bland-Altman analysis was used to test data dispersion. RESULTS: Ten patients were excluded due to a systematic error in the gas calibrator. The mean (SD) time to stabilization of the monitor before reading was 13.9 (2.4) minutes. The forced expiratory volume in the first second was greater than 80% in 40 patients, between 60% and 79% in 23, between 40% and 59% in 30, and less than 40% in 37. The mean (SD) differences between arterial blood gas measurements were 0.28 (1.0) mm Hg for PaCO2, -0.06% (0.86%) for SaO2, and -0.9 (2.7) mm Hg for PaO2. In the tests for correlation and agreement, r was 0.74 and ICC was 0.73 for SaO2 and SpO2; r was 0.92 and ICC was 0.92 for PaCO2 and TcPCO2. The subgroup analyses did not show any noteworthy differences. The Bland Altman analysis showed no significant dispersion. It was observed that the SenTec monitor underestimated oxygen saturation values by around 1% with respect to SaO2 and overestimated carbon dioxide pressure by 1 mm Hg with respect to PaCO2 values. CONCLUSIONS: The stabilization time recommended for the SenTec monitor before taking a reading is 20 minutes. The overestimates and underestimates by the monitor are not clinically relevant. Finally, the values for SpO2 and TcPCO2 measured by the validated monitor are reliable.

Las plantas medicinales, patrimonio natural y cultural de la Reserva Hídrica Natural y Recreativa Bamba, La Calera, Córdoba, Argentina / Medicinal plants, natural and cultural heritage of the Bamba Natural and Recreational Water Reserve, La Calera, Córdoba, Argentina

Herbal medicine has played a leading role in the health systems of many traditional societies. The main objective is to characterize an aspect of the natural and cultural heritage of a protected area of the town of La Calera, through the documentation of medicinal plants of the Bamba Water and Recreational Nature Reserve (RNHRB), in the province of Córdoba, Argentina. Methodologies of social and natural sciences, typical of ethnoecological approaches, were combined, complementing with qualitative and quantitative analyzes. A total of 221 uses corresponding to 137 medicinal species were documented. The most relevant families in terms of quantity of species and uses are Asteraceae, Fabaceae and Lamiaceae. In all cases the native / wild status predominates. Applications associated with gastrointestinal conditions are the most frequent, followed by dermatological, pneumonological, infectological and nephrological. It is concluded that herbal medicine in protected areas provides valuable information and efforts for the conservation of biocultural heritage in intangible rural areas with urbanized spaces, as well as for the potencial knowledge and use of resources by small local producers.

La medicina herbaria ha desempeñado un papel de liderazgo en los sistemas de salud de muchas sociedades tradicionales. El objetivo principal es caracterizar un aspecto del patrimonio natural y cultural de un área protegida de la localidad de La Calera, a través de la documentación de plantas medicinales de la Reserva Natural Acuática y Recreativa de Bamba (RNHRB), en la provincia de Córdoba, Argentina. Se combinaron metodologías de las ciencias sociales y naturales, propias de los enfoques etnoecológicos, complementando con análisis cualitativos y cuantitativos. Se documentaron un total de 221 usos correspondientes a 137 especies medicinales. Las familias más relevantes en cuanto a cantidad de especies y usos son Asteraceae, Fabaceae y Lamiaceae. En todos los casos predomina el estado nativo/salvaje. Las aplicaciones asociadas a afecciones gastrointestinales son las más frecuentes, seguidas de las dermatológicas, neumonológicas, infecciosas y nefrológicas. Se concluye que la fitoterapia en áreas protegidas brinda valiosa información y esfuerzos para la conservación del patrimonio biocultural en áreas rurales intangibles con espacios urbanizados, así como para el potencial conocimiento y uso de recursos por parte de pequeños productores locales.

Long-term prostate-specific antigen contamination in the Spanish arm of the European Randomized Study of Screening for Prostate Cancer (ERSPC).

OBJECTIVES: Recently, the European Randomized Study of Screening for Prostate Cancer achieved a reduction in prostate cancer mortality by measuring serum prostate-specific antigen (PSA) levels. These results were not reproduced in the Spanish arm of European Randomized Study of Screening for Prostate Cancer. PSA contamination (opportunistic measurements outside the study) could decrease the study's contrasting power if performed in the control arm. We have calculated the long-term rate of PSA contamination and its effect on performing prostate biopsy and detecting cancer. MATERIAL AND METHODS: A total of 4,276 men were randomised (2,415 to the screening arm, 1,861 to the control arm) in the Spanish section of the European Randomized Study of Screening for Prostate Cancer. PSA measurements were not scheduled in the control arm. Sextant prostate biopsy was indicated if PSA levels were ≥3 ng/mL. All PSA readings performed outside the study were labelled as "PSA contamination". We calculated the rates of PSA contamination, biopsy implementation and cancer detection. RESULTS: The median age and follow-up time were 57 and 15.1 years, respectively. A total of 2,511 men underwent at least one PSA reading outside the study. PSA contamination at 5, 10 and 15 years was 22.0%, 47.1% and 66.3% in the screening arm, respectively, and 20.8%, 43.2% and 58.6% in the control arm, respectively (P<.0001). The biopsy rate at 5, 10 and 15 years was 19.3%, 22.6% and 24.1% (screening), respectively, and 1.0%, 3.6% and 7.1% (control), respectively (P<.0001). The PC detection rate was 6.7% (screening) and 4.3% (control; P=.0006). CONCLUSIONS: Although the cumulative PSA contamination was pronounced in the 2 study arms, the rate of prostate biopsies was low in the control arm. We therefore believe that the effect of PSA contamination on the study's statistical power should be limited.