Proline cis-trans isomerization and its implications for the dimerization of analogues of cyclopeptide stylostatin 1: a combined computational and experimental study.

Cis and trans proline conformers are often associated with dramatic changes in the biological function of peptides. A slow equilibrium between cis and trans Ile-Pro amide bond conformers occurs in constrained derivatives of the native marine cyclic heptapeptide stylostatin 1 (cyclo-(NSLAIPF)), a potential anticancer agent. In this work, four cyclopeptides, cyclo-(NSTAIPF), cyclo-(KSTAIPF), cyclo-(RSTAIPF) and cyclo-(DSTAIPF), which are structurally related to stylostatin 1, are experimentally and computationally examined in order to assess the effect of residue mutations on the cis-trans conformational ratio and the apparent capacity to form dimeric aggregates. Primarily, cyclo-(KSTAIPF) and cyclo-(RSTAIPF) showed specific trends in circular dichroism, MALDI-TOF and HPLC purification experiments, which suggests the occurrence of peptide dimerization. Meanwhile, the NMR spectrum of cyclo-(KSTAIPF) indicates that this cyclopeptide exists in the two slow-exchange families of conformations mentioned above. Molecular dynamics simulations combined with quantum mechanical calculations have shed light on the factors governing the cis/trans conformational ratio. In particular, we have found that residue mutations affect the internal hydrogen bond pattern which ultimately tunes the cis/trans conformational ratio and that only trans conformers are capable of aggregating due to the shape complementarity of the two subunits.

Optimización de los aislamientos preventivos en una UCI polivalente mediante la aplicación de un plan de intervención / Optimization of pre-emptive isolations in a polyvalent ICU through implementation of an intervention strategy

ANTECEDENTES: El aislamiento preventivo consiste en la aplicación de medidas de aislamiento de contacto en pacientes con alta sospecha de estar colonizados por bacterias multirresistentes. OBJETIVO: Evaluar el impacto de un programa de intervención basado en la implantación de un Protocolo Consensuado de Aislamiento Preventivo (PCAP) al ingreso en una UCI polivalente de un hospital general. MÉTODO: Análisis comparativo de 2 cohortes de pacientes, una histórica, que incluye pacientes a los que se indicó el aislamiento preventivo a juicio del médico responsable (enero de 2010 a febrero de 2011), y otra prospectiva, que incluye los pacientes a los que se aplicó el PCAP (marzo a noviembre de 2011). El PCAP incluyó la identificación y divulgación de los criterios de aislamiento preventivo, la metodología a seguir en cuanto a toma de muestras, la valoración de los resultados y los criterios de retirada del aislamiento. La indicación del aislamiento fue realizada por el personal médico, y un equipo de enfermería realizó el seguimiento. Se definió el aislamiento preventivo como «adecuado» cuando en alguna de las muestras iniciales se identificó una bacteria multirresistente. Para la comparación de resultados entre los 2 periodos se utiliza la chi cuadrado para variables cualitativas y la t de Student para variables cuantitativas. Se aceptan como significativas diferencias con p < 0,05. RESULTADOS: De los 1.740 pacientes ingresados en UCI (1.055 en el primer periodo y 685 en el segundo) se indicó el aislamiento preventivo en 199 (11,4%), de los que 111 (10,5%) correspondieron a la fase histórica (grupo control) y 88 (12,8%) a la fase posterior a la implantación del PCAP (grupo de intervención). No se han detectado diferencias en la edad, el APACHE II y las características de los pacientes entre los 2 periodos. La aplicación del PCAP se ha relacionado con una disminución de los aislamientos preventivos no indicados (29,7 vs. 6,8%, p < 0,001), una disminución del tiempo en la solicitud de las muestras de vigilancia (1,56 vs. 0,37 días, p < 0,001), y una disminución de la duración en días del aislamiento (4,77 vs. 3,58 días, p < 0,001). En 44 pacientes (22,1%) en los que se indicó el aislamiento preventivo se identificaron más de una bacteria multirresistente, siendo la tasa de «aislamiento preventivo adecuado» del 19,8% en el primer periodo y del 25,0% en el segundo (p < 0,382). CONCLUSIONES: Tras la instauración de PCAP se han reducido significativamente los aislamientos preventivos no indicados correctamente, se ha disminuido el tiempo entre el aislamiento y la toma de muestras, además de reducirse la duración del aislamiento en los casos en que no es necesario, sin que haya aumentado la tasa de «aislamiento preventivo adecuado»

BACKGROUND: Pre-emptive isolation refers to the application of contact precaution measures in patients with strongly suspected colonization by multiresistant bacteria. OBJECTIVE: To assess the impact of an intervention program involving the implementation of a consensus-based protocol of pre-emptive isolation (CPPI) on admission to a polyvalent ICU of a general hospital. METHODS: A comparative analysis of 2 patient cohorts was made: a historical cohort including patients in which pre-emptive isolation was established according to physician criterion prior to starting CPPI (from January 2010 to February 2011), and a prospective cohort including patients in which CPPI was implemented (from March to November 2011). CPPI included the identification and diffusion of pre-emptive isolation criteria, the definition of sampling methodology, the evaluation of results, and the development of criteria for discontinuation of pre-emptive isolation. Pre-emptive isolation was indicated by the medical staff, and follow-up was conducted by the nursing staff. Pre-emptive isolation was defined as "adequate" when at least one multiresistant bacteria was identified in any of the samples. Comparison of data between the 2 periods was made with the chi-square test for categorical variables and the Student t-test for quantitative variables. Statistical significance was set at P < .05. RESULTS: Among the 1,740 patients admitted to the ICU (1,055 during the first period and 685 during the second period), pre-emptive isolation was indicated in 199 (11.4%); 111 (10.5%) of these subjects corresponded to the historical cohort (control group) and 88 (12.8%) to the posterior phase after the implementation of CPPI (intervention group). No differences were found in age, APACHE II score or patient characteristics between the 2 periods. The implementation of CPPI was related to decreases in non-indicated pre-emptive isolations (29.7 vs. 6.8%, P<.001), time of requesting surveillance cultures (1.56 vs. 0.37 days, P<.001), and days of duration of treatment (4.77 vs. 3.58 days, P<.001). In 44 patients (22.1%) in which pre-emptive isolation was indicated, more than one multiresistant bacteria was identified, with an "adequate pre-emptive isolation rate” of 19.8% in the first period and 25.0% in the second period (P<.382). CONCLUSIONS: The implementation of CPPI resulted in a significant decrease in pre-emptive isolations which were not indicated correctly, a decrease in the time elapsed between isolation and collection of samples, and a decrease in the duration of isolation measures in cases in which isolation was unnecessary, without increasing the rate of "adequate pre-emptive isolation"

Optimization of pre-emptive isolations in a polyvalent ICU through implementation of an intervention strategy.

BACKGROUND: Pre-emptive isolation refers to the application of contact precaution measures in patients with strongly suspected colonization by multiresistant bacteria. OBJECTIVE: To assess the impact of an intervention program involving the implementation of a consensus-based protocol of pre-emptive isolation (CPPI) on admission to a polyvalent ICU of a general hospital. METHODS: A comparative analysis of 2 patient cohorts was made: a historical cohort including patients in which pre-emptive isolation was established according to physician criterion prior to starting CPPI (from January 2010 to February 2011), and a prospective cohort including patients in which CPPI was implemented (from March to November 2011). CPPI included the identification and diffusion of pre-emptive isolation criteria, the definition of sampling methodology, the evaluation of results, and the development of criteria for discontinuation of pre-emptive isolation. Pre-emptive isolation was indicated by the medical staff, and follow-up was conducted by the nursing staff. Pre-emptive isolation was defined as "adequate" when at least one multiresistant bacteria was identified in any of the samples. Comparison of data between the 2 periods was made with the chi-square test for categorical variables and the Student t-test for quantitative variables. Statistical significance was set at P<.05. RESULTS: Among the 1,740 patients admitted to the ICU (1,055 during the first period and 685 during the second period), pre-emptive isolation was indicated in 199 (11.4%); 111 (10.5%) of these subjects corresponded to the historical cohort (control group) and 88 (12.8%) to the posterior phase after the implementation of CPPI (intervention group). No differences were found in age, APACHE II score or patient characteristics between the 2 periods. The implementation of CPPI was related to decreases in non-indicated pre-emptive isolations (29.7 vs. 6.8%, P<.001), time of requesting surveillance cultures (1.56 vs. 0.37 days, P<.001), and days of duration of treatment (4.77 vs. 3.58 days, P<.001). In 44 patients (22.1%) in which pre-emptive isolation was indicated, more than one multiresistant bacteria was identified, with an "adequate pre-emptive isolation rate" of 19.8% in the first period and 25.0% in the second period (P<.382). CONCLUSIONS: The implementation of CPPI resulted in a significant decrease in pre-emptive isolations which were not indicated correctly, a decrease in the time elapsed between isolation and collection of samples, and a decrease in the duration of isolation measures in cases in which isolation was unnecessary, without increasing the rate of "adequate pre-emptive isolation".

Organochlorine pesticides in umbilical cord blood serum of women from Southern Spain and adherence to the Mediterranean diet.

Exposure of pregnant women to organochlorine (OC) pesticides largely derives from contaminated food, but environmental, occupational, and domestic factors have also been implicated. We investigated the presence of nine OC residues in the umbilical cord blood of newborns in Southern Spain and analyzed the relationship of this exposure with maternal and pregnancy variables, including maternal adherence to the Mediterranean Diet (MD). OCs were detected in 95% of umbilical cord blood samples from the 318 mothers, who had a mean degree of adherence to the MD of 56.77 (SD: 16.35) (range, 0-100). The MD prioritizes consumption of vegetable and fruit over meat and dairy products, and OCs are generally lipophilic molecules that accumulate in foods of animal origin. Consumption of meat, fish, and dairy products was associated with dichlorodiphenyldichloroethylene (DDE) in umbilical cord serum, and dairy product intake with lindane. Vegetable consumption was also associated with lindane and fruit intake with endosulfan I. We found no significant association between MD adherence and the presence of OC residues in serum. However, closer adherence to the MD may offer greater protection against OC exposure because of its reduced content in meat and dairy products.

Factores etiopatogénicos del asma bronquial en la edad infantil / Etiological and pathogenic factors of bronchial asthma in childhood

Introducción: Hay muchos factores implicados en el desarrollo y la progresión del asma bronquial infantil. Objetivo: Valorar si estos factores están claramente implicados en la etiopatogenia de esta enfermedad. Material y métodos: Revisión bibliográfica estructurada de los trabajos sobre factores de riesgo para el asma publicados en bibliografía biomédica actualizada durante los últimos 5 años. Resultados: Se han seleccionado 14 artículos que aporta datos a favor y en contra sobre los factores considerados de riesgo para el desarrollo y la progresión del asma bronquial como la genética o los antecedentes familiares, la atopía, las anomalías de la función pulmonar, el sexo, la lactancia materna y los estilos de alimentación, el tabaco, las infecciones respiratorias virales y otros factores ambientales (hipótesis de la higiene). Conclusiones: Hay discordancia entre la implicación de los diferentes factores etiopatogénicos del asma con la propia enfermedad

Introduction: There are many factors implicated in the development and progression of childhood bronchial asthma. Objective: To determine whether these factors are clear involved in the etiology and pathogenesis of this disease. Material and methods: Structured review of the articles dealing with risk factors for asthma published in the biomedicé literature updated over the last 5 years. Results: The authorss elected fourteen articles that contribute information in favor of and against the factors considered indicate risk for the development and progression of bronchial asthma. These include genetics or family history, atopy, abnormal lung function, sex, breastfeeding and eating habits, smoking, viral respiratory infections and environmental factors (the hygiene hypothesis).Conclusions: There is no consensus as to the involvement (the different etiological and pathogenic factors associate with asthma in the disease itself

[Malnutrition prevalence in patients admitted to a rehabilitation and orthopedic surgery hospital]. / Prevalencia de desnutrición en pacientes ingresados en un hospital de rehabilitación y traumatología.

OBJECTIVE: Different studies show the scarce attention granted to the nutritional state in historical and clinical practice, what determines the ignorance of the patient's nutritional status to their entrance in the hospital and, therefore, the impossibility to prevent the hospital malnutrition. The objective of our study has been to determine the prevalence of patients' malnutrition entered in a Hospital of Orthopedic surgery and Rehabilitation. METHODS: Observational and analytical study in 250 randomized patients (60% men and 40% women), who were nutritionally evaluated when entering, the hospital, by means of anthropometry (Weigh, height, BMI, skin-fold, corporal circumferences) and biochemical tests (Albumin, Prealbumin and Transferrin). RESULTS: According to the BMI the prevalence of malnutrition was of 8%, the average of caloric malnutrition was of 2.8% (according to anthropometry) and the prevalence of many-sided malnutrition rises to 54.8% (according to biochemical markers). CONCLUSIONS: The high prevalence of fundamental malnutrition (54.8%) demonstrated in this study, it shows the importance of determining the nutritional status when entering the hospital, particularly surgical type' patiens as is the case of most of those who enter the Orthopedic surgery hospitals.

Prevalencia de desnutrición en pacientes ingresados en un hospital de rehabilitación y traumatología / Malnutrition prevalence in patients admitted to a rehabilitation and orthopedic surgery hospital

Objetivo: Diferentes estudios ponen de manifiesto la escasa atención concedida al estado nutricional en la historia y práctica clínica, lo que determina el desconocimiento del estado nutricional del paciente a su ingreso en el hospital y por tanto la imposibilidad de prevenir la malnutrición hospitalaria. El objetivo de nuestro estudio ha sido determinar la prevalencia de desnutrición de pacientes ingresados en un Hospital de Traumatología y Rehabilitación. Métodos: Estudio observacional analítico en 250 pacientes (60% hombres y 40% mujeres) seleccionados aleatoriamente, a los que se realizó una evaluación nutricional al ingreso hospitalario, mediante antropometría (Peso, talla, IMC, PB, PCT, PCSA y PCSE) y pruebas bioquímicas (Albúmina, Prealbúmina y Transferrina). Resultados: Según el IMC la prevalencia de desnutrición fue del 8%, el promedio de desnutrición de tipo calórico fue del 2,8% (según antropometría) y la prevalencia de desnutrición proteica se eleva al 54,8% (según marcadores bioquímicos). Conclusiones: La elevada prevalencia de malnutrición proteica o visceral (54,8%) demostrada en este estudio, pone de manifiesto la importancia de determinar el estado nutricional al ingreso hospitalario, particularmente en los pacientes de tipo quirúrgico, como es el caso de la mayoría de los que ingresan en los hospitales traumatológicos (AU)

Objective: Different studies show the scarce attention granted to the nutritional state in historical and clinical practice, what determines the ignorance of the patient's nutritional status to their entrance in the hospital and, therefore, the impossibility to prevent the hospital malnutrition. The objective of our study has been to determine the prevalence of patients' malnutrition entered in a Hospital of Orthopedic surgery and Rehabilitation. Methods: Observational and analytical study in 250 randomized patients (60% men and 40% women), who were nutritionally evaluated when entering, the hospital, by means of anthropometry (Weigh, height, BMI, skinfold, corporal circumferences) and biochemical tests (Albumin, Prealbumin and Transferrin). Results: According to the BMI the prevalence of malnutrition was of 8%, the average of caloric malnutrition was of 2,8% (according to anthropometry) and the prevalence of many-sided malnutrition rises to 54,8% (according to biochemical markers). Conclusions: The high prevalence of fundamental malnutrition (54,8%) demonstrated in this study, it shows the importance of determining the nutritional status when entering the hospital, particularly surgical type' patiens as is the case of most of those who enter the Orthopedic surgery hospitals (AU)

Procedimiento diagnóstico-terapéutico en un paciente con perforación espontánea de sigma y sospecha de síndrome de Ehlers-Danlos tipo IV / Diagnostic-therapeutic procedure in a patient with spontaneous perforation of the sigmoid colon and suspected Ehlers-Danlos syndrome type IV

El síndrome de Ehlers-Danlos es una enfermedad hereditaria del metabolismo del colágeno tipo III. La sospecha clínica se confirma con el cultivo de fibroblastos del paciente y la demostración de un defecto en su metabolismo. Este síndrome tiene como una de sus manifestaciones más graves la perforación espontánea del colon. Se aporta el caso de un paciente con perforación espontánea de colon al que se le practicó procedimiento de Hartmann y cuya enfermedad de base se confirmó con posterioridad.La confirmación del síndrome de Ehlers-Danlos se realizó con microscopia electrónica de muestras de biopsia de la piel del paciente y se confirmó con cultivo de fibroblastos. El diagnóstico definitivo hizo cambiar la estrategia quirúrgica realizándose colectomía total e ileoproctostomía (AU)

Estudio prospectivo de la colecistectomía laparoscópica urgente frente a diferida como tratamiento de la colecistitis aguda de corta evolución / Prospective study of emergency versus delayed laparoscopic cholecystectomy to treat acute cholecystitis of short duration

Introducción. El objetivo del estudio es valorar la eficacia del tratamiento laparoscópico urgente de la colecistitis aguda de corta evolución frente al tratamiento conservador inicial y posterior colecistectomía laparoscópica diferida. Pacientes y método. Estudio comparativo entre 30 pacientes con colecistitis aguda de menos de 72 h de evolución intervenidos mediante colecistectomía laparoscópica de urgencia y 41 pacientes con colecistitis aguda de menos de 72 h de evolución con tratamiento inicial conservador y posterior colecistectomía laparoscópica diferida. Se estudian las variables quirúrgicas, estancias hospitalarias y complicaciones postoperatorias de ambos grupos. Resultados. Se observaron diferencias estadísticamente significativas para el tiempo quirúrgico y la tasa de conversión, que fueron menores en el grupo de colecistectomía laparoscópica diferida. Se observó igual proporción de complicaciones para ambos grupos. La estancia hospitalaria global fue significativamente menor en el grupo de colecistectomía laparoscópica de urgencia. Conclusiones. La colecistectomía laparoscópica en las primeras 72 h de evolución del cuadro clínico de colecistitis aguda es un procedimiento eficaz como tratamiento definitivo de la colelitiasis sintomática y obtiene mejores resultados que el tratamiento conservador inicial y posterior colecistectomía laparoscópica diferida (AU)

Cirugía laparoscópica ante la sospecha clínica de apendicitis aguda. Estudio prospectivo de 500 casos consecutivos / Laparoscopic surgery and the clinical suspicion of acute appendicitis. Prospective study of 500 consecutive cases

Introducción. La apendicitis aguda es uno de los cuadros clínicos más frecuentes en la patología quirúrgica. El objetivo del presente estudio es valorar los resultados de la utilización de la exploración laparoscópica ante la sospecha clínica de apendicitis aguda. Pacientes y método. Análisis prospectivo de los resultados obtenidos en 500 exploraciones laparoscópicas consecutivas por sospecha de apendicitis aguda. Aplicación de un score de predicción de complicaciones sépticas intraabdominales. Resultados. En el 83,2 por ciento de los procedimientos, el diagnóstico de apendicitis aguda fue correcto. La causa más frecuente de error diagnóstico fue la enfermedad ginecológica. Se llegó a un diagnóstico definitivo en el 98,2 por ciento de los casos. El 93,75 por ciento de los casos de apendicitis aguda se pudieron resolver por vía laparoscópica. La aplicación de un score predictivo permitió reducir el porcentaje de complicaciones sépticas intraabdominales de un 5,5 a un 1,3 por ciento. Conclusiones. La laparoscopia permite una elevada certeza diagnóstica y una alta rentabilidad terapéutica. La aplicación de un score predictivo de complicaciones sépticas intraabdominales permite reducir drásticamente el porcentaje de presentación de abscesos intraabdominales (AU)

Aneurisma de la arteria gastroduodenal: tratamiento mediante embolización selectiva / An aneurysm for the gastroduodenal artery: its treatment via selective embolization

No disponible

Serum and urine selenium concentrations in patients with cardiovascular diseases and relationship to other nutritional indexes.

Serum and urine selenium levels were determined in patients with cardiovascular diseases by hydride generation atomic absorption spectrometry. Mean serum Se concentrations measured in patients with acute myocardial infarction (AMI; n = 32) or with ischemic cardiomyopathy (n = 50) were significantly lower than those determined in control groups. In AMI patients, serum triglyceride levels showed a positive significant correlation with the serum Se concentration (r = 0.59, p < 0.05). This result reinforces the important role of Se as an antioxidant agent in this disease. Mean urine Se concentrations of AMI patients (n = 33) were also significantly lower to those determined in the control group (p < 0. 05). This reaction of the organism contributes to regulate the Se homeostasis to keep the body Se status as high as possible.

Serum and urine selenium concentrations as indicators of body status in patients with diabetes mellitus.

Serum and urine selenium levels were determined in patients with diabetes by hydride generation atomic absorption spectrometry. Mean serum selenium concentrations measured in patients with diabetes mellitus (64.9 +/- 22.8 micrograms/l) were significantly lower than those determined in the control group (74.9 +/- 27.3 micrograms/l) (P < 0.05). Mean serum selenium concentrations were not significantly different between the two groups of diabetic patients considered (P > 0.05). Mean urine selenium concentration in diabetic patients (18.8 +/- 10.7 micrograms/l) were not significantly different from those measured in the control group (20.2 +/- 10.1 micrograms/l) (P < 0.05). No significant differences in serum and urine selenium levels were found if related to sex of patients (P > 0.05). Application of linear regression analysis to serum and urine selenium levels and patients' age showed a non-statistically significant correlation (P > 0.05). Given the marked overlap between the two ranges of the populations, the predictive values of serum selenium in diabetic patients are low.

[Experience in the management of the HIV patient among the physicians of the Secretaría de Salud]. / Experiencia en el manejo del paciente con VIH entre médicos de la Secretaría de Salud.

OBJECTIVE: To determine the experience of the National Health Ministry physicians in the management of HIV-infected patients and in the use of antiretrovirals. MATERIAL AND METHOD: A descriptive, observational and transversal study was performed, with support from the National AIDS Council from March to May 1998. Self-applicable questionnaires were filled by National Health Ministry physicians with experience in HIV patient clinical care, at the beginning of 5 different meetings on HIV/AIDS in several cities of the country. Statistical analysis included the chi-square test. RESULTS: One hundred and eighty-one questionnaires were applied. The median of HIV patients attended by physicians was 4 (interval 1-97); 36.5% of the physicians had used antiretrovirals (35.4% prescribed nucleoside analogs and 9.9% protease inhibitors). The most frequently used drugs were AZT and/or ddl (40.3%); 17.7% had administered CD4+ lymphocyte count and 8.8% viral load. CONCLUSIONS: The proportion of National Health Ministry physicians with experience in VIH patient care was low, as was the use of antiretrovirals. Efforts should be focus on improving care of HIV patients through physician training.

[Zidovudine plus didanosine in HIV infected asymptomatic patients previously treated with zidovudine]. / Zidovudina más didanosina en pacientes asintomáticos infectados por VIH previamente tratados con zidovudina.

OBJECTIVE: To evaluate if the combination of AZT/ddl offered any advantages in surrogate markers among HIV infected asymptomatic patients previously treated with AZT for at least six months. METHODS: We used a prospective cohort of 269 asymptomatic HIV patients with CD4+ cell counts between 200 and 500 cells/microL. They were given didanosine (ddl 400 mg/d) in addition to AZT (500 mg/d) and had received AZT monotherapy for an average of 20 months. End points were progression to AIDS, death, or toxicity. RESULTS: Median CD4+ cell count at the start of the combination therapy was 339 cells/microL which increased at three months to 451 and subsequently declined at 6, 12 and 18 months of followup (medians of 392, 360, 307 cells/microL respectively). Five patients progressed to AIDS, six developed toxicity (myelosuppression, hepatitis or pancreatitis) and 26 had minor side effects that required only dose reduction. CONCLUSIONS: The addition of ddl to patients with prolonged ZDV monotherapy can be useful. CD4+ T cell counts showed a significant increase at 3 months with a gradual subsequent decline to below baseline at 18 months. Adverse effect of the drugs, although frequent, did not stop therapy in most patients.

Serum selenium levels as indicators of body status in cancer patients and their relationship with other nutritional and biochemical markers.

A cross-sectional study of serum selenium levels in patients (n = 59) with different types of cancer from southeastern Spain was carried out using hydride generation atomic absorption spectrometry. The subjects were divided into four groups according to the cancer location (respiratory, digestive, haematological and gynaecological groups). Serum selenium levels in all patients (54.41 +/- 24.80 mg/l) were significantly lower (P < 0.001) than those determined in control groups [healthy subjects from the same area (n = 130) and institutionalized elderly people (n = 93)]. Mean serum selenium concentrations were not significantly different among the four groups considered (P > 0.05). Linear regression analyses performed on serum selenium levels and biochemical markers (total cholesterol, triglycerides, transaminases, uric acid and urea) did not establish any statistically significant correlation (P > 0.05). No significant relationships between serum selenium concentrations and sex or age of patients was observed (P > 0.05). Given the marked overlap between the two ranges of the populations (the means are within approx. 1/2 S.D.) the predictive values of serum selenium are low. Thus, there is indeed a statistical significance between the means, but selenium cannot be used to determine whether or not a patient has cancer disease.