Evaluation of the PECARN rule for traumatic brain injury applied to infants younger than 3 months and creation of a modified, age-specific rule.

Infants < 3 months with minor head trauma (MHT) are a particularly vulnerable group, though few studies have focused specifically on these patients. We aimed to evaluate the application of the PECARN prediction rule, designed for clinically important traumatic brain injury (ciTBI) in children < 2 years in infants < 3 months, and create a specific prediction rule for this population. We conducted a prospective multicenter observational study in 13 pediatric emergency departments (PEDs) in Spain. The PECARN rule was applied to all patients. A new specific prediction rule for infants < 3 months of age was created. The main outcome measures were (1) ciTBI, (2) TBI evidenced on computed tomography (CT) scan, and (3) isolated skull fracture (ISF). Telephone follow-up was conducted for all patients over the 4 weeks after the initial PED visit. Of 21,981 children with MHT, 366 (1.7%) were < 3 months old and 195 (53.3%) underwent neuroimaging, including 37 (10.1%) with CT scan. The sensitivity and negative predictive value (NPV) of the PECARN prediction rule for ciTBI were 100% (95% CI, 20.7-100) and 99.7% (95% CI, 98.4-100%), respectively. Of the 230 infants (62.8%) who met the PECARN low-risk criteria, none had ciTBI, 1 (0.4% overall, 95% CI, 0-2.4) had TBI on CT, and 2 (0.9% overall; 95% CI, 0.1-3.1) had an ISF. Among the 136 infants (37.2%) who did not meet the PECARN low-risk criteria, 1 (0.3% overall; 95% CI, 0-1.5) had ciTBI, 11 (8.1% overall; 95% CI, 4.1-14.0) had TBI on CT, and 18 (13.2% overall; 95% CI, 8-20.1) had an ISF. The sensitivity and NPV of the Spanish prediction rule for ciTBI were 100% (95% CI, 20.7-100) and 100% (95% CI, 98.4-100%), respectively. No infants in the registry developed complications during follow-up. CONCLUSION: The PECARN rule for infants < 2 years old accurately identified infants < 3 months old at low risk for ciTBI in our population, although the adapted Spanish rule presented here could be even more accurate. WHAT IS KNOWN: • Infants younger than 3 months are vulnerable to minor blunt head trauma due to their age and to difficulties in assessing the subtle symptoms and minimal physical findings detected on examination. • A low threshold for CT scan is recommended in this population. WHAT IS NEW: • PECARN rule for infants < 2 years old is an adequate tool with which to identify infants < 3 months old at low risk for clinically important traumatic brain injury. • Spanish rule could identify even more low-risk infants without overlooking important outcomes but it should be validated to confirm its predictive capacity.

Epidemiology of minor blunt head trauma in infants younger than 3 months.

Specific knowledge of the features of minor head trauma in infants is necessary to develop appropriate preventive strategies and adjust clinical management in pediatric emergency departments (PEDs). The aim of this study is to describe the epidemiology of minor blunt head trauma in infants < 3 months who present to PEDs. We performed a prospective study of infants evaluated in any of 13 Spanish PEDs within 24 h of a minor head trauma (Glasgow Coma Scale scores of 14-15) between May 2017 and November 2020. Telephone follow-up was conducted for all patients over the 4 weeks after the initial PED visit. Of 1,150,255 visits recorded, 21,981 children (1.9%) sustained a head injury, 386 of whom (0.03%) were under 3 months old. Among the 369 patients who met the inclusion criteria (0.03%), 206 (56.3%) were male. The main causes of trauma were fall-related (298; 80.8%), either from furniture (138/298; 46.3%), strollers (92/298; 30.9%), or a caregiver's arms (61/298; 20.5%). Most infants were asymptomatic (317; 85.9%) and showed no signs of injury on physical exam (210; 56.9%). Imaging studies were performed in 195 patients (52.8%): 37 (10.0%) underwent computed tomography (CT) scan, 162 (43.9%) X-ray, and 22 (6.0%) ultrasound. A clinically important traumatic brain injury (ciTBI) occurred in 1 infant (0.3% overall; 95% CI, 0-1.5), TBI was evidenced on CT scan in 12 (3.3% overall; 95% CI, 1.7-5.7), and 20 infants had an isolated skull fracture (5.5% overall; 95% CI, 3.4-8.3). All outcomes were caused by falls onto hard surfaces. CONCLUSION:  Most head injuries in infants younger than 3 months are benign, and the rate of ciTBI is low. Prevention strategies should focus on falls onto hard surfaces from furniture, strollers, and caregivers' arms. Optimizing imaging studies should be a priority in this population. WHAT IS KNOWN: • Infants younger than 3 months are vulnerable to minor blunt head trauma due to their age and to difficulties in assessing the subtle symptoms and minimal physical findings detected on examination. • A low threshold for CT scan is recommended in this population. WHAT IS NEW: • Most cases of blunt head trauma in infants younger than 3 months have good outcomes, and the rate of clinically important traumatic brain injury is low. • Optimizing imaging studies should be a priority in this population, avoiding X-ray examinations and reducing unnecessary CT scans.

Increased Severity of Mycoplasma pneumoniae Infections in Spanish Children.

BACKGROUND: Since the end of 2023, an elevated incidence and severity of Mycoplasma pneumoniae infections among children in Asia has been noted. Subsequently, this trend was observed in several European countries although limited data are currently available. We conducted a national study to delineate the ongoing M. pneumoniae outbreak in our country. METHODS: A multicenter retrospective observational study was conducted across 32 hospitals in Spain, encompassing patients under 18 years old hospitalized for M. pneumoniae infection from January 2023 to March 2024. Infection was confirmed by positive polymerase chain reaction and/or by 2 serological tests. RESULTS: A total of 623 children were included, with 79% of cases diagnosed in the final 3 months of the study period. Pneumonia was the most common diagnosis (87%). Respiratory symptoms were present in 97% of cases, with 62% requiring oxygen supplementation and 14% requiring admission to the pediatric intensive care unit (PICU). Risk factors for PICU admission included the presence of neurological symptoms, hypoxemia and a history of prematurity. Children admitted to the PICU exhibited significantly higher neutrophil counts upon admission. CONCLUSIONS: We have observed a notable increase in hospital admissions, including PICU support by up to 14%, due to M. pneumoniae infection in our country since November 2023, indicative of a more severe clinical course associated with this pathogen.

Quantifying the available capacity and resource needs for provision of CAR-T therapies in the National Health Service in Spain: a survey-based study.

OBJECTIVES: To estimate the readiness of Spanish National Health Service (NHS) hospitals to provide chimeric antigen receptor T cell (CAR-T), and to identify and quantify the different resources needed to provide CAR-T considering three scenarios defined by 10, 25 and 50 patients per centre per year. DESIGN: Targeted literature review and quantitative study using a questionnaire and telephone interviews. An algorithm was created to determine hospitals' readiness based on their capacity and capability. All the requirements for quantification were assessed and validated by the steering committee, formed by members of the Spanish Group of Haematopoietic Transplantation and Cell Therapy. A weighting system (from 0 to 1) was established for capability quantification. For resources quantification, a scoring system was established, with 0 points representing the minimum and 3 points the maximum of additional resources that a hospital indicated necessary. SETTING: 40 Spanish hospital centres that perform allogeneic haematopoietic stem cell transplantation were invited to complete the questionnaire for capacity quantification, 28 of which provided valid responses. Nine hospitals participated in the interviews for resource quantification, eight of which had previously been designated by the Ministry of Health (MoH) to provide CAR-T. OUTCOME MEASURE: Current capacity of NHS Spanish sites to administer CAR-T under different theoretical scenarios with varying numbers of procedures, and the potential healthcare resources that would be needed to realise the theoretical capacity requirements. RESULTS: Four hospitals were optimally ready, 17 were somewhat ready and 7 were not ready. The actual extrapolated capacity of the currently designated MoH CAR-T sites would allow treatment of approximately 250 patients per year. Regarding healthcare resource needs, the numbers of haematologists, nurses and beds were the most important limiting factors, and those requiring further growth as patient numbers increased. CONCLUSIONS: Increasing the number of CAR-T-qualified centres and/or increasing resources in the current designated sites are two potential strategies that should be considered to treat CAR-T-eligible patients in Spain.

Impact of SCHOLAR-1 Criteria on Chimeric Antigen Receptor T Cell Therapy Efficacy in Aggressive B Lymphoma: A Real-World GELTAMO/GETH Study.

In the pre-chimeric antigen receptor T cell (CAR-T) therapy era, the SCHOLAR-1 study identified a group of patients with refractory aggressive B cell lymphoma (ABCL) with particularly poor prognoses. We recently published our real-world data from Spain, focused on this SCHOLAR-1 refractory group, and compared patients who underwent CAR-T therapy with the previous standard of care. In this study, we found that the efficacy of CAR-T therapy in refractory patients, in terms of progression-free survival (PFS) and overall survival (OS), was superior to that of the treatments available in the pre-CAR-T era. The main objective of these new analyses was to analyze treatment efficacy in terms of response rates and survival for patients with ABCL with or without the SCHOLAR-1 criteria. In addition, we analyzed the prognostic impact of each SCHOLAR-1 criterion independently. Our study aimed to assess the prognostic impact of SCHOLAR-1 criteria on ABCL patients treated with CAR-T therapy in Spain. This multicenter, retrospective, observational study. We included all adult patients treated with commercially available CAR-T cell products and diagnosed with ABCL different from primary mediastinal large B cell lymphoma between February 2019 and July 2022. Patients meeting any SCHOLAR-1 criteria (progressive disease as the best response to any line of therapy, stable disease as the best response to ≥4 cycles of first-line therapy or ≥2 cycles of later-line therapy, or relapse at <12 months after autologous stem cell transplantation [auto-SCT]) in the line of treatment before CAR-T therapy (SCHOLAR-1 group) were compared with those not meeting any of these criteria (non-SCHOLAR-1 group). To analyze the prognostic impact of individual SCHOLAR-1 criteria, all the patients who met any of the SCHOLAR-1 criteria at any time were included to assess whether these criteria have the same prognostic impact in the CAR-T era. In addition, patients were grouped according to whether they were refractory to the first line of treatment, refractory to the last line of treatment, or relapsed early after auto-SCT. The PFS and OS were calculated from the time of appearance of the SCHOLAR-1 refractoriness criteria. Of 329 patients treated with CAR-T (169 with axi-cel and 160 with tisa-cel), 52 were in the non-SCHOLAR-1 group and 277 were in the SCHOLAR-1 group. We found significantly better outcomes in the non-SCHOLAR-1 patients compared with the SCHOLAR-1 patients (median PFS of 12.2 and 3.3 months, respectively; P = .009). In addition, axi-cel showed better results in terms of efficacy than tisa-cel for both the non-SCHOLAR-1 group (hazard ratio [HR] for PFS, 2.7 [95% confidence interval (CI), 1.1 to 6.7; P = .028]; HR for OS, 7.1 [95% CI, 1.5 to 34.6; P = .015]) and SCHOLAR-1 group (HR for PFS, 1.8 [95% CI, 1.3 to 2.5; P < .001]; HR for OS, 1.8 [95% CI, 1.2 to 2.6; P = .002]), but also significantly more toxicity. Finally, separately analyzing the prognostic impact of each SCHOLAR-1 criterion revealed that refractoriness to the last line of treatment was the variable with the most significant impact on survival. In conclusion, SCHOLAR-1 refractoriness criteria notably influence the efficacy of CAR-T therapy. In our experience, axi-cel showed better efficacy than tisa-cel for both SCHOLAR-1 and non-SCHOLAR-1 patients. Refractoriness to the last line of treatment was the variable with the most significant impact on survival in the CAR-T therapy era.

Does Small-Scale Livestock Production Use a High Technological Level to Survive? Evidence from Dairy Production in Northeast-ern Michoacán, Mexico.

The objective of this study was to identify the technological level used by dairy farmers in the northeastern region of Michoacán, Mexico, through a characterisation of small-scale dairy production units, as well as to learn about the socioeconomic conditions that have enabled them to survive in the current context. A semi-structured interview was applied to 114 production units, chosen by stratified random sampling. The interview included technological, production and socioeconomic aspects. Twenty-eight variables were initially explored and 12 were used for multivariate analysis, which included Principal Component Analysis, Hierarchical Cluster Analysis and K-means Cluster. The characterisation carried out showed that the production units that predominate in northeastern Michoacán have survived with a low technological level, having as strengths the diversification of their activities and the use of family labour. On the contrary, production units with a high technological level and high productivity are few and less diversified. This shows the need to generate differentiated public policies for each cluster, aimed at strengthening the aspects that have allowed them to survive and guaranteeing a market for their production, before promoting the use of technologies.

[Epidemiologic and situational panorama of hepatitis C in Mexico]. / Panorama epidemiológico y situacional de la hepatitis C en México.

OBJECTIVE: To determine the epidemiological situation of Chronic Hepatitis C (CHC) in our country. BACKGROUND DATA: Chronic Hepatitis C affects 170 million people worldwide, and about 0.7% of Mexican population. There is no enough epidemiological information about CHC in our country, and it is very probable that some cases are not even detected. METHODS: An investigation poll was performed. Age, gender, birthday, weight, race, residence and birth place, routes of transmission, ALT levels, histological, serological and molecular diagnosis, evidence of complications and previous treatments were recorded. A data recollection sheet was dispatched to different country provinces; they had 6 months to answer it, in order to recollect all information. RESULTS: 831 patients were analized (58.6% female and 41.4% male) with the following distribution in our country provinces: Aguascalientes 15, Chihuahua 12, Distrito Federal 495, Durango 10, Jalisco 89, Guanajuato 78, Yucatán 8, Querétaro 11, Sonora 40, Tabasco 15, Baja California 5, Veracruz 13, Tamaulipas 2 and 38 patients of Nuevo León. The highest incidence of CHC was found at fifth and sixth decade of life (28.5% y 26.7% respectively. The weight distribution was 36.2% < 65kg, 34.6% 65-75 kg and 29.2% > 75 kg. 86.5% had chronic hepatitis and 13.2% cirrhosis. The risk factors for HCV infection analysis showed that the main route of transmission was via contaminated blood (64.2%); when we excluded the patients that were exposed before 1995, the incidence was lowered to 4.5%. The higher incidence was showed between 1970 and 1990 (68%). The intravenous drug users were predominantly male and on those patients in the provinces near the north border line of our country. The predominant genotype was gen- 1 no matter the province (72.2%), in the intravenous drug users genotype 3 was found in 25%. The viral load was similar in all the provinces. 75% of the patients had have treatment and 22.5% had have two cycles, 50% of cirrhotic patients had have treatment whereas only 28% of the patients with late complications had have it. The most common treatment was pegylated alpha-2a interferon plus ribavirine. CONCLUSIONS: 1. The main route of transmission was blood transfusion. There is a marked decrease in the incidence of post-transfusional hepatitis since the introduction of anti-VHC antibody screening of blood donors (4.5%). 2. The time between the infection and diagnosis was 23 years for chronic hepatitis and 26 years for cirrhosis. 3. Intravenous drugs use was an important route of transmission in the north of our country. 4. The predominant genotype was gen-1. 5. Almost all the patients with chronic hepatitis received treatment, the most common used was pegylated interferon alpha-2a and ribavirin. 6.50% of the patients with CHC have late complications.

[The use of pulsed echo-Doppler in verifying the patency of by-passes and reconstructions of the humeral artery]. / Utilización de EcoDoppler pulsado en la comprobación de la permeabilidad de by-passes y reconstrucciones de la arteria humeral.

Personal experiences using Duplex as alternative method to the invasive techniques in 17 patients after the surgical restoration of their injured humeral arteries, are presented. Duplex was used during the control and also during the follow-up of the surgical procedures.

[Importance of morphologic evaluation of carotid lesions in their correlation with cerebral ischemic pathology]. / Importancia de la valoración morfológica de las lesiones carotídeas en su correlación con patología isquémica cerebral.

Authors present a review of 182 atheromatous plaques into the extracranial carotid trunks. Diagnosis of such pathologies were made by Eco-Doppler on 615 patients. Objective was to determinate the emboligen potential of the plaques following structural and functional criteria. Almost all the symptomatic plaques with functional disturbances showed some structural injury with emboligen potential. Two third parts of all the symptomatic diseases hemodynamically no-significant were associated with plaques with emboligen power. On stenosis higher than 70%, functional criterium was more important for study than structural criterium.

[Role of rituximab in the management of refractory autoimmune cytopenia]. / Rituximab en el tratamiento de citopenias autoinmunitarias refractarias a tratamientos convencionales.

OBJECTIVES: This study examined the efficacy of rituximab in children with refractory autoimmune cytopenia. MATERIAL AND METHODS: Longitudinal descriptive study comprising a series of clinical cases (n=7) during the period 2003 to 2010. RESULTS: A series 7 patients were included (4 had primary immune thrombocytopenia, 2 autoimmune hemolytic anemia, and 1 autoimmune neutropenia). One patient had received stem cell transplantation. Rituximab was administered intravenously to all patients at a dose of 375 mg/mg(2) weekly. Four patients received 4 doses. Three patients received 2, 6, and 8 doses, respectively. Overall, 5 patients responded (4 complete responses plus 1 partial response). The median time to achieve complete response was 8.5 weeks (range: 3.5-19.5 weeks). Two patients achieved complete response in the first 3.5 weeks, and the remaining 3 patients between 8.5 and 19.5 weeks. The median time of response was 35.5 weeks (range: 12.5-53.5 weeks). Two patients relapsed. No serious adverse events were recorded. CONCLUSIONS: Overall, seventy one percent of patients in this study respond to treatment, 100% of responders decrease their previous treatment. Rituximab was a well tolerated and no related serious side effects were recorded during the study period.

Hábitos tóxicos en estudiantes de segundo año de medicina / Toxic habits in second year medical students

Se realizó un estudio descriptivo y transversal durante marzo del 2012 para determinar los hábitos tóxicos de 42 estudiantes de segundo año de medicina, pertenecientes a la Facultad No. 2 de la Universidad de Ciencias Médicas de Santiago Cuba, para lo cual se aplicó una encuesta anónima que recogía datos sociodemográficos y variables de interés para la investigación. Entre los principales resultados predominaron el sexo femenino y los educandos entre 18 y 19 años. También sobresalieron el café, el alcohol y el tabaco como drogas lícitas más consumidas; los medicamentos no recetados como drogas ilícitas más empleadas, además de la cerveza, el ron y alcohol preparado como bebidas más frecuentes. La mayoría de los estudiantes desconocían el daño que ocasionan las drogas ilícitas a la salud de los individuos.

A descriptive and cross-sectional study was carried out during March, 2012 to determine the toxic habits of 42 second year medical students, belonging to Faculty No. 2 of the Medical Sciences University in Santiago de Cuba, for which an anonymous survey was applied which compiled social and demographic data and variables of interest for the investigation. Female sex and the students between 18 and 19 years prevailed among the main results. Coffee, alcohol and tobacco were the most consumed licit drugs; the over-the-counter drugs were the most used illicit drugs, besides beer, rum and prepared alcohol, were the most frequent drinks. Most of the students ignored the damages caused by the illicit drugs to the health of the individuals.

Factores contribuyentes al abandono de la lactancia materna exclusiva en un área de salud / Factors contributing to exclusive breastfeeding discontinuation in a health area

Se realizó un estudio longitudinal, prospectivo, observacional y descriptivo de 40 mujeres, atendidas en el consultorio No. 26 del Policlínico Universitario "Josué País García" de Santiago de Cuba, desde enero del 2011 hasta igual mes del 2012, a fin de identificar los factores contribuyentes al abandono de la lactancia materna exclusiva. Entre las variables analizadas figuraron: edad de la madre, enfermedades crónicas, paridad, nivel socioeconómico, escolaridad y presencia de complicaciones en el parto. En la casuística, las madres que primero abandonaron la lactancia materna fueron las de 15-19 años (42,5 %), nulíparas (32,5 %), con nivel socioeconómico bajo (50,0 %) y escolaridad primaria. Se demostró que las complicaciones durante el parto influyeron en el abandono de este tipo de lactancia.

A longitudinal, prospective, observational and descriptive study was conducted in 40 women, treated at the doctor's office No. 26 of "Josué País García" University Polyclinic in Santiago de Cuba, from January 2011 to the same month of 2012, in order to identify the factors contributing to exclusive breastfeeding discontinuation. Among the analyzed variables were mother's age, chronic diseases, parity, socioeconomic status, education and complications in childbirth. In the case material, mothers who first discontinued breastfeeding were those between 15-19 years of age (42.5%), nulliparous (32.5%), with low socioeconomic status (50.0%) and primary education. It was demonstrated that complications during the childbirth influenced the discontinuation of this type of feeding.

Tiña corporis en pacientes venezolanos atendidos en la consulta de Dermatología de un Centro de Diagnóstico Integral / Tinea corporis in Venezuelan patients attended in the Dermatology Department from the Comprehensive Diagnosis Center

Se realizó un estudio longitudinal y prospectivo de 2 340 pacientes con Tinea corporis que acudieron a la consulta de Dermatología del Centro de Diagnóstico Integral "El Bajo" del municipio de San Francisco (Venezuela), de enero a diciembre del 2010, con vistas a determinar las características de la enfermedad en estos, la cual constituyó la segunda causa de morbilidad dermatológica en la serie. Predominaron el sexo masculino, el grupo etario de 20-29 años, las caderas como la región anatómica más afectada, las lesiones únicas y las de bordes definidos. A pesar de las diferentes medidas higienicoepidemiológicas llevadas a cabo, la tiña corporis todavía resulta un problema de salud, por lo que se deben efectuar intervenciones educativas en toda la población venezolana, de modo que sean modificados los factores de riesgos de la infección.

A longitudinal and prospective study was conducted in 2 340 patients with Tinea corporis that went to the Dermatology Department from "El Bajo" Comprehensive Diagnosis Center of San Francisco municipality (Venezuela), from January to December 2010, with the purpose of determining the characteristics of the disease in these patients, which was the second leading cause of dermatological morbidity in the series. Male sex, the age group of 20-29 years, the hips as the most affected anatomical site, single lesions and lesions of defined edges prevailed. Despite the different epidemiological health measures undertaken, tinea corporis is still a health problem, therefore educational interventions must be implemented in all Venezuelan population, so that the risk factors for infection are modified.

Los canales y márgenes de comercialización de la leche cruda producida en sistema familiar (estudio de caso) / Marketing channels and margins of raw milk produced in a family system (case study)

A field study was carried out to identify marketing channels and margins of "raw milk" (milk that is marketed without any physical or chemical treatment) produced in a community of Maravatio municipality, in Michoacan State, in the west-central portion of Mexico. The research method had a first recognition phase with acceptance of the work group by the community. Direct observation was carried out and visits were made with milk gatherers who filled out a questionnaire to record traded milk in liters, and to estimate their marketing costs and their gross marketing margin (GMM), net marketing margin (NMM) and producer direct participation (PDP). Information that was captured and processed permitted the identification of five gatherers, of which only two sell "raw milk" directly, the other three transform and market it as dairy products. Results show existence of two types of marketing channels, one is zero level or direct marketing channel and the other is of only one level. Estimated margins for the gatherers that market "raw milk" on average are: GMM, 31.7%; PDP, 68.3%; and NMM, considering the cost of opportunity of labor, would be 20.1 %, while without taking it into consideration it would be 25.7%. Margins indicate that the activity of gatherer is revenue-yielding and it gives an economic incentive to continue with that activity, especially if the gatherer does not have a better cost of opportunity for labor. The above is not applicable to the producer, since he must consider his production costs.

Se realizó un estudio para conocer los canales y márgenes de comercialización de la "leche cruda" (leche comercializada sin haber pasado por ningún tratamiento físico o químico) producida en una comunidad del municipio de Maravatío, Michoacán, en la parte centro-occidental de México. El método de investigación consistió en una primera fase de reconocimiento y aceptación del grupo de trabajo en la comunidad. Se realizó observación directa y recorridos con los acopiadores, a quienes se les aplicó un cuestionario orientado a registrar los litros de leche comercializados y estimar sus costos de comercialización y su margen bruto de comercialización (MBC), el margen neto de comercialización (MNC) y la participación directa del productor (PDP). La información que se capturó y procesó permitió identificar cinco acopiadores, de los cuales sólo dos venden directamente la "leche cruda", los otros tres la transforman y comercializan como derivados lácteos. Los resultados muestran la existencia de dos tipos de canales de comercialización: el del nivel cero o canal directo de mercado y el de un solo nivel. Los márgenes calculados para los acopiadores que comercializan la "leche cruda", en promedio, son: MBC, 31.7%; PDP, 68.3%; y MNC, considerando el costo de oportunidad de la mano de obra, 20.1%, y sin considerarlo, 25.7%. Los márgenes indican que la actividad del acopiador es redituable y le suministra un estímulo económico para continuar con dicha actividad, sobre todo si este acopiador no obtiene un mejor costo de oportunidad por la mano de obra. Lo anterior no es aplicable para el productor, pues hay que considerar sus costos de producción.