COVID-19 vaccines and adverse events of special interest: A multinational Global Vaccine Data Network (GVDN) cohort study of 99 million vaccinated individuals.

BACKGROUND: The Global COVID Vaccine Safety (GCoVS) Project, established in 2021 under the multinational Global Vaccine Data Network™ (GVDN®), facilitates comprehensive assessment of vaccine safety. This study aimed to evaluate the risk of adverse events of special interest (AESI) following COVID-19 vaccination from 10 sites across eight countries. METHODS: Using a common protocol, this observational cohort study compared observed with expected rates of 13 selected AESI across neurological, haematological, and cardiac outcomes. Expected rates were obtained by participating sites using pre-COVID-19 vaccination healthcare data stratified by age and sex. Observed rates were reported from the same healthcare datasets since COVID-19 vaccination program rollout. AESI occurring up to 42 days following vaccination with mRNA (BNT162b2 and mRNA-1273) and adenovirus-vector (ChAdOx1) vaccines were included in the primary analysis. Risks were assessed using observed versus expected (OE) ratios with 95 % confidence intervals. Prioritised potential safety signals were those with lower bound of the 95 % confidence interval (LBCI) greater than 1.5. RESULTS: Participants included 99,068,901 vaccinated individuals. In total, 183,559,462 doses of BNT162b2, 36,178,442 doses of mRNA-1273, and 23,093,399 doses of ChAdOx1 were administered across participating sites in the study period. Risk periods following homologous vaccination schedules contributed 23,168,335 person-years of follow-up. OE ratios with LBCI > 1.5 were observed for Guillain-Barré syndrome (2.49, 95 % CI: 2.15, 2.87) and cerebral venous sinus thrombosis (3.23, 95 % CI: 2.51, 4.09) following the first dose of ChAdOx1 vaccine. Acute disseminated encephalomyelitis showed an OE ratio of 3.78 (95 % CI: 1.52, 7.78) following the first dose of mRNA-1273 vaccine. The OE ratios for myocarditis and pericarditis following BNT162b2, mRNA-1273, and ChAdOx1 were significantly increased with LBCIs > 1.5. CONCLUSION: This multi-country analysis confirmed pre-established safety signals for myocarditis, pericarditis, Guillain-Barré syndrome, and cerebral venous sinus thrombosis. Other potential safety signals that require further investigation were identified.

Estudio retrospectivo en pacientes con Cáncer de Colon etapa III. ¿El tratamiento adyuvante es iniciado de forma oportuna?

Introducción: En Chile, el Cáncer colorrectal (CC) abarca el 11,5% de todas las neoplasias malignas. La cirugía es la piedra angular del tratamiento del cáncer de colon, y en pacientes en etapa III, la quimioterapia adyuvante forma parte del tratamiento estándar. Materiales y Métodos: Estudio descriptivo retrospectivo transversal, de centro único, de pacientes con cáncer de colon en estadio III patológico. Objetivo principal de este estudio es conocer si, en pacientes con cáncer de colon etapa III, la quimioterapia adyuvante se entrega de manera oportuna. Resultados: En el período comprendido entre abril de 2016 y abril de 2021 se operaron 35 pacientes con cáncer de colon en estadio III patológico. Se realizó quimioterapia adyuvante en un 80%, y en siete pacientes durante las primeras ocho semanas poscirugía. La dehiscencia de anastomosis ocurrió en un 11,4%, aumentando la mediana de hospitalización en 2,2 veces. Discusión: En nuestro estudio, la adyuvancia en cáncer de colon etapa III se administró a un alto porcentaje de los pacientes (80%), pero observamos un retraso importante, ya que sólo en un 25% se inició el tratamiento durante las primeras 8 semanas poscirugía, lo cual puede ser explicado por múltiples factores, siendo la dehiscencia de anastomosis un punto importante a considerar. Conclusión: En estadio III de CC la adyuvancia puede verse retrasada por múltiples factores, lo que puede repercutir en la sobrevida de los pacientes, por lo tanto, conocer las causas de este retraso podría ayudar a instaurar nuevas estrategias, como la neoadyuvancia, para mejorar los resultados oncológicos.

Introduction: In Chile, colorectal cancer covers 11.5% of all malignant neoplasms. Surgery is the cor- nerstone of colon cancer treatment and in stage III patients adjuvant chemotherapy is part of standard treatment. Materials and Methods: A descriptive, retrospective, cross-sectional study, single center, of patients with pathological stage III colon cancer. Main objective of this study is to know if in patients with stage III colon cancer adjuvant chemotherapy is delivered in a timely manner. Results: Between April 2016 and April 2021, 35 patients with pathological stage III colon cancer were operated on. Adjuvant chemotherapy was performed in 80%, and in seven patient during the first eight weeks after surgery. Anastomotic dehiscence occurred in 11.4%, the median hospitalization increased by 2.2 times. Discussion: In this study, adjuvant stage III colon cancer was administered to a high percentage of patients (80%), but we observed a significant delay, since only 25% began treatment during the first 8 weeks post-surgery, which can be explained by multiple factors, with anastomotic dehiscence being an important point to consider. Conclusion: In stage III CC, adjuvant treatment can be delayed by multiple factors, which may affect patient survival; therefore, knowing the causes of this delay could help to establish new strategies, such as neoadjuvant therapy, to improve oncological results.

Conocimientos y prácticas en anticoncepción de los estudiantes de medicina y enfermería de Manizales, Colombia 2015 / Knowledge and practices in contraception of medical and nursing students of Manizales

PROPÓSITO Establecer el grado de conocimientos y prácticas que tienen los estudiantes de medicina y enfermería de último año de Manizales, Colombia, respecto a los programas de anticoncepción. MATERIAL Y MÉTODO En el segundo semestre de 2015 se citaron los estudiantes de los cuatro programas de medicina y enfermería que existen en la ciudad. A quienes aceptaron participar se les entregaron secuencialmente tres formularios: uno con casos clínicos para argumentar el método más indicado o contraindicado, el segundo con preguntas de respuesta múltiple y el tercero con preguntas relativas al aspecto curricular. La información fue procesada en SPSS versión 20, licenciado a la Universidad de Caldas; se utilizaron mediciones de frecuencia, tablas de contingencia y significancia menor a 0,05. RESULTADOS Se obtuvieron 140 encuestas de estudiantes de medicina y 134 de enfermería. La calificación general de los casos clínicos, sobre una calificación máxima posible de 5,0, presentó una media de 2,557 (IC: 2,468; 2,644) y la del segundo formulario fue de 2,146 (IC: 2,060; 2,233). En el análisis de las respuestas al cuestionario de selección múltiple se encontraron diferencias significativas entre los estudiantes de los dos programas. Respecto a los aspectos curriculares, se encontró que los estudiantes recibieron entre 5 y 8 horas teóricas, presenciaron la recomendación del DIU 2,68 veces, lo insertaron en un simulador 1,73 veces y lo vio insertar o lo insertó en menos de una vez. CONCLUSIÓN Los estudiantes de medicina y de enfermería tienen un insuficiente nivel de conocimientos y de prácticas en anticoncepción.

OBJECTIVE To establish the degree of knowledge and practices that the students of medicine and nursing of last year of Manizales, Colombia, have about the contraception programs. MATERIAL AND METHOD In the second term of 2015, the students of four medical and nursing programs in Manizales were called. Those who agreed to participate were given three forms: one with clinical cases to argue the most indicated or contraindicated method, the second with multiple-choice questions and the third with questions related to the curricular aspect. The information was processed in SPSS version 20, licensed to Universidad de Caldas; frequency measurements, contingency tables and significance less than 0.05 were used. RESULTS 140 surveys of medical students and 134 of nursing students were obtained. The overall score of clinical cases, with a maximum possible score of 5.0, presented an average of 2,557 (CI: 2,468; 2,644) and for the second form was of 2,146 (CI: 2,060; 2,233). In the analysis of multiple choice questionnaire responses, significant differences were found between the students of the two programs. Regarding the curricular aspects, it was found that the students received between 5 - 8 theoretical hours, they observed the IUD recommendation 2.68 times, inserted it in a simulator 1.73 times and saw it inserted or inserted in less than once. CONCLUSION Medical and nursing students have insufficient knowledge and practices in contraception.

Unilateral variation in the origin of the inferior alveolar and buccal arteries: a case report / Variación unilateral en el origen de las arterias alveolar inferior y bucal: reporte de un caso

The maxillary artery (MA) is one of the terminal branches of the external carotid artery (ECA) and is located in the infratemporal fossa (IF). Some of the branches in this region are the inferior alveolar artery (IAA) and the buccal artery (BA), both descending branches. Here, we report an unusual unilateral origin of the IAA and the BA from a common trunk directly from the ECA. We conducted a routine dissection of both IF in a 54-year-old hispanic male cadaver. Fixed with Universidad de los Andes® conservative solution and red latex for vascular filling. On each side, the MA is observed superficially located over the lateral pterygoid muscle. On the right side, the IAA and the BA originate from a common trunk from the ECA approximately 5 mm prior to the bifurcation into their terminal branches. On the left side, the IAA originates from the MA that is immediately next to its origin, making a common trunk with the pterygoid branches. Knowing the morphology of the MA and its branches at the IF is important for oral and maxillofacial surgery procedures; and any variation in the origin or course of these arteries may result in the patient's increased morbidity during some invasive procedure in the area.

La arteria maxilar (AM) es una rama terminal de la arteria carótida externa (ACE), y se ubica en la región infratemporal (RI). Algunas de sus ramas en esta región son la arteria alveolar inferior (AAI) y la arteria bucal (AB), ambas ramas descendentes. En este trabajo informamos de un inusual origen unilateral de la AAI y de la AB a partir de un tronco común desde la ACE. Se realizó una disección de rutina de ambas regiones infratemporales en un cadáver de 54 años, sexo masculino, caucásico. Fijado con solución conservadora Universidad de los Andes® y repleción vascular con látex rojo. A cada lado, se observa la AM en ubicación superficial sobre el músculo pterigoideo lateral. Al lado derecho, la AAI y la AB se originan de un tronco común desde la ACE aproximadamente 5 mm antes de la bifurcación en sus ramas terminales. Al lado izquierdo la AAI se origina de la AM inmediato a su origen, formando un tronco común con los ramos pterigoideos. El conocimiento de la morfología de la AM y de sus ramas en la RI es de importancia en procedimientos odontológicos, de cirugía oral y maxilofacial. Por lo que cualquier variación en el origen o trayecto de estas arterias puede predisponer a un paciente a una mayor morbilidad durante algún procedimiento invasivo en la zona.

Tumores de colon de expansión lateral: características en nuestra población / Laterally spreading tumors: characteristics in our population

Introduction: Colorectal cancer is a rising disease worldwide. In Chile, it is the third leading cause of death associated to gastrointestinal cancer. Optimal preventive management requires surveillance of precursor lesions or early-stage tumors. Laterally spreading tumors (LST) are categorized as nonpolypoid colorectal neoplasms. Since there are no demographic data on these lesions in our country, the aim of our study was to describe the characteristics of LSTs based on our department’s data. Methods: We reviewed the department’s colonoscopy database from 1996 to 2006 to obtain clinical, endoscopic and histological data. We excluded patients with family history of polyposis, prior colorectal cancer and inflammatory bowel disease. Results: Out of 3713 colonoscopies performed, 364 (9.8 percent) adenoma cases were detected; 42 (1.2 percent) of them were catalogued as LSTs. Thirty-three LST patients had complete data and were included in the study. The gender proportion was similar between male and female. Ages ranged from 35 and 92 years (mean +/- SD 66.7 +/- 13.7). The tumor size ranged from 10 to 120 mm (mean +/- SD 28.2 +/- 28.3). According to distribution along the large bowel, 19 (57.5 percent) LSTs were located distally and 14 (42.5 percent) were proximal to the splenic flexure. Histology showed 26 adenomas (14 of them with high-grade dysplasia), 5 adenocarcinomas and 2 hyperplastic lesions. Conclusion: In Chile, LSTs are mainly found in the elderly. It is important to detect these lesions because most of them contain cancer or high-grade dysplasia. Therefore, during colonoscopy, we should focus not only on polypoid lesions, but also on flat lesions.

Introducción: El cáncer colorrectal es una enfermedad emergente a nivel mundial. En nuestro país es la tercera causa de muerte por cáncer del tubo digestivo. Un óptimo manejo preventivo implica la detección y tratamiento de las lesiones precursoras y los cánceres incipientes. Los tumores de expansión lateral (Laterally spreading tumors-LST) se consideran lesiones precursoras no polipoídeas. En Chile no existen datos demográficos de estas lesiones, por lo que el objetivo de este estudio es caracterizar los LST en nuestra población. Métodos: Revisamos la base de datos de las colonoscopias realizadas en nuestro Instituto desde 1996 al 2006, obteniendo datos clínicos y las características endoscópicas e histológicas. Excluimos los pacientes con historia de poliposis familiar, cáncer colorrectal y enfermedad inflamatoria intestinal. Resultados: De 3.713 colonoscopias, se detectaron 364 (9,8 por ciento) casos diagnosticados como adenoma, lesiones planas o LST, de los cuales 42 (1,2 por ciento) se catalogaron como LST. Sólo 33 pacientes con LST tenían disponible el estudio histológico. La proporción por género fue similar entre hombres (17) y mujeres (16). El rango de edad se distribuyó entre 35 y 92 años (promedio +/- DE 66,7 +/- 13,7); el tamaño tumoral fue de 10 a 120 mm (promedio +/- DE 28,2 +/- 28,3). De acuerdo a la distribución en el colon y recto, 19 (57,5 por ciento) LST se localizaron distales al ángulo esplénico y 14 (42,5 por ciento) proximales. El estudio histológico demostró 26 adenomas, 14 de los cuales presentaban displasia de alto grado, 5 adenocarcinomas y 2 lesiones hiperplásicas. Conclusión: En nuestra población los LST se presentan mayoritariamente en la tercera edad. Es importante la detección de estas lesiones, dado que en su mayoría contienen un cáncer o son adenomas con displasia de alto grado. Durante la colonoscopia no solamente debemos enfocarnos en los pólipos sino también en las lesiones planas.

A comparison of stavudine, didanosine and indinavir with zidovudine, lamivudine and indinavir for the initial treatment of HIV-1 infected individuals: selection of thymidine analog regimen therapy (START II).

OBJECTIVE: Comparison of stavudine (d4T), didanosine (ddI) and indinavir (IDV) with zidovudine (ZDV), lamivudine (3TC) and IDV in HIV-1 infected patients. DESIGN: Randomized, open-label. SETTING: Fourteen HIV Clinical Research Centers. PATIENTS: Two-hundred and five patients with less than 4 weeks antiretroviral treatment, naive to 3TC and protease inhibitors and with CD4 cell counts > or = 200 x 10(6)/l and plasma HIV-1 RNA levels > or = 10,000 copies/ml. INTERVENTIONS: Stavudine 40 mg and ddI 200 mg twice daily plus IDV 800 mg every 8 h compared with ZDV 200 mg every 8 h or 300 mg twice daily, 3TC 150 mg twice daily plus IDV. MAIN OUTCOME MEASURES: The proportion of patients with plasma HIV-1 RNA levels < 500 copies/ml and < or = 50 copies/ml and changes in CD4 cell counts were compared. RESULTS: In an analysis of the primary endpoint, 61% of patients on d4T + ddI + IDV and 45% of patients on ZDV + 3TC + IDV had all HIV-1 RNA values obtained between weeks 40 and 48 < 500 copies/ml [95% confidence interval (CI) for the difference between proportions, 1.7-30.3%; P = 0.038]. In an intent-to-treat analysis, the percentage of all patients randomized with all HIV-1 RNA levels < 500 copies/ml between 40 and 48 weeks were 53% for the d4T + ddI + IDV arm and 41% for the ZDV + 3TC + IDV arm (95% CI, -1.4% to 25.7%; P = 0.068). At 48 weeks 41% and 35% were < or = 50 copies/ml for the stavudine- and ZDV-containing arms respectively (P > 0.2). The median time-weighted average increases in CD4 cells count over 48 weeks were 150 x 10(6)/l cells for the d4T arm and 106 x 10(6)/l cells for the ZDV arm (P= 0.001). The occurrence of serious adverse events was not significantly different between arms. CONCLUSION: The combination of stavudine, ddl and IDV resulted in potent antiretroviral effects over a 48-week period, comparable or superior to zidovudine, 3TC and IDV supporting the use of stavudine, ddI and a protease inhibitor as an initial antiretroviral treatment.

Lamivudine plus zidovudine compared with zalcitabine plus zidovudine in patients with HIV infection. A randomized, double-blind, placebo-controlled trial. North American HIV Working Party.

OBJECTIVE: To compare the safety and activity of lamivudine plus zidovudine with the safety and activity of zalcitabine plus zidovudine in patients with moderately advanced human immunodeficiency virus (HIV) infection who had received zidovudine. DESIGN: A multicenter, randomized, double-blind, three-arm, 24-week study with a blinded extension through at least 52 weeks. SETTING: 21 sites in the United States, Canada, and Puerto Rico. PATIENTS: 254 patients who had received zidovudine (median duration of previous therapy, 20 months) and had absolute CD4+ cell counts of 100 to 300 cells/mm3. INTERVENTIONS: Patients were randomly assigned to receive one of three regimens: 150 mg of lamivudine twice daily plus 200 mg of zidovudine three times daily (low-dose lamivudine group); 300 mg of lamivudine twice daily plus 200 mg of zidovudine three times daily (high-dose lamivudine group); or 0.75 mg of zalcitabine plus 200 mg of zidovudine three times daily (zalcitabine group). MEASUREMENTS: Immunologic activity was assessed primarily by changes in absolute CD4+ cell counts; virologic activity was assessed by changes in plasma HIV RNA levels as measured by reverse transcriptase polymerase chain reaction. Safety of the treatment regimens was assessed through the reporting of adverse events. RESULTS: 78% of patients completed 24 weeks of study treatment, and 63% of patients completed 52 weeks of study treatment. Changes in absolute CD4+ cell counts were significantly better for the low-dose and the high-dose lamivudine groups than for the zalcitabine group (median changes at 52 weeks were +42.5 cells/mm3 in the low-dose lamivudine group, +23.33 cells/mm3 in the high-dose lamivudine group, and -29.58 cells/mm3 in the zalcitabine group). Suppression of plasma HIV RNA levels was similar for all groups (median changes at 52 weeks were -0.48 log10 copies/mL in the low-dose lamivudine group, -0.51 log10 copies/mL in the high-dose lamivudine group, and -0.39 log10 copies/mL in the zalcitabine group). No significant differences in safety were seen among the three regimens, although the low-dose lamivudine regimen appeared to be better tolerated than the others. CONCLUSIONS: In patients with HIV infection who had previously received zidovudine, 150 mg of lamivudine plus zidovudine resulted in greater immunologic evidence of benefit than did 0.75 mg of zalcitabine plus zidovudine and was better tolerated than 300 mg of lamivudine plus zidovudine.

Evaluation of the acrosomal membrane in bovine spermatozoa: effects of proteinase inhibitors.

Thawed bovine spermatozoa are characterized by a lack of homogeneity in the acrosomal membrane. Therefore, it is difficult to visualize the acrosome to assess morphology. Synthetic proteinase inhibitors were tested on thawed bovine semen for their effect on the integrity of acrosomal membranes. The proteinase inhibitors 4-nitrophenyl-4-guanidinobenzoate (NPGB) and N-L-p-tosyl-L-lysine-chloromethylketone (TLCK) were added to a medium containing spermatozoa separated on a percoll gradient. After incubation for 30 min at 38 degrees C in 5% CO(2), 95% air (final concentration 1 mM), the action of these inhibitors was controlled by measuring the activity of acrosome proteinases. The acrosomal membrane was evaluated by means of a dual stain procedure (trypan blue, Giemsa). In contrast to spermatozoa that had been incubated with proteinase inhibitor-free solution, samples that had been incubated with TLCK showed homogeneity in 90% of the acrosomal membranes and excellent visualization of the acrosome itself; in the NPGB-treated samples, homogeneous staining was observed in 83% of spermatozoa (P < 0.0005). It is concluded that alteration of the acrosomal membrane in thawed semen is not directly caused by freezing-thawing, but may be due to activation of acrosomal proteinases, which is increased during staining procedures. The addition of proteinase inhibitors before staining offers a new possibility for improved assessment of the acrosome in bovine spermatozoa.

Involvement of ETA receptors in the facilitation by endothelin-1 of non-adrenergic non-cholinergic transmission in the rat urinary bladder.

1. Endothelin-1 (ET-1; 3-10 nM) raised the tone of rat bladders bathed in buffer containing atropine (1 microM) plus guanethidine (3.4 microM). In addition, ET-1 potentiated, in a concentration-dependent fashion (1-10 nM), the contractions evoked by both transmural nerve stimulation and applications of exogenous adenosine 5'-triphosphate (ATP). 2. The threshold concentration of ET-1 required to facilitate non-adrenergic non-cholinergic (NANC) transmission and potentiate ATP-induced contractions, was about 10 fold lower than that required to increase the bladder tone (3 nM). 3. The ET-1-induced increase in basal tension reached its maximal effect within 60-90 s. In contrast, the 7.8 microM ATP-induced contractions increased by 50% within the first minute following incubation with 10 nM ET-1 but required about 5 min to develop the maximal effect. 4. The ET-1-induced potentiation of NANC or ATP responses was long-lasting and persisted in spite of extensive washing. The recovery of the bladder excitability depended on the concentration of ET-1. Following the application of 3 nM ET-1, recovery required 30 min; applications of 10 nM ET-1 required at least 60 min for full recovery. 5. The ET-1-induced potentiation of responses was selective for ATP and related structural analogues. ET-1 did not modify the contractions induced by acetylcholine, 5-hydroxytryptamine, prostaglandin F2 alpha or bradykinin. 6. The potency of ET-2 was similar to that of ET-1. ET-3 and ET-C-terminal hexapeptide were inactive up to 100 M. Sarafotoxin S6b was 2 to 3 fold less potent than ET-1 whereas sarafotoxin S6c (100 nM) was inactive. AGETB-9 and AGETB-89, two ETB receptor agonists, were also inactive (up to 100 nM). 7. Removal of one or both disulphide bonds in ET-1 and tryptophan-21 formylation of ET-1, resulted in inactive peptides (up to 100 nM). 8. The ET-1 receptor antagonists, BE-18257B and FR 139317, blocked both the ET-1-induced rise in tone and the potentiation of ATP responses in a concentration-dependent fashion. FR 139317 was at least 30 fold more potent than BE-18257B. Both antagonists blocked at lower concentrations the ET-1 increase in bladder tone as compared to the ATP potentiation. The antagonism was slowly reversible. 9. Results are consistent with the presence of ETA receptors in the rat bladder, which mediate both actions of ET-1. The interaction of ET-1 with purinergic mechanisms is discussed.

[Parental socialization styles and psychosocial development in 16 to 19 year old adolescents]. / Estilos de socialización de los padres y desarrollo psicosocial en adolescentes de 16 a 19 años.

To study relationships between perceptions that 16 to 19 year old adolescents have about socialization styles and disciplinary methods used by their parents, with their view of the world, interpersonal relations, moral development, use of psychotropic substances and maladjusted behaviours, 241 adolescents--123 males--which belong to a follow up study on growth and development from northern metropolitan Santiago, Chile, were asked to answer a questionary of psychosocial development, previously elaborated by two of the authors (GS and CA). The most used socialization styles by these fathers and mothers were the negative power one (39.2% and 38.5%) and the inductive one (23.8% and 30.0%), while permissive styles occurred at much lower frequency (1.5% and 1.1%). Coincidence among parents in socialization styles was found in 47.7% and disagreement in 19.2% of cases. The inductive style and coincidence in it's use by both parents, were frequently associated to idealistic world views, autonomous and conventional moral development, satisfactory interpersonal relationships and low frequency of psychotropic consumption, and maladjusted behaviours while negative power based styles by both parents and disagreement of styles among them were rather related to realistic or negative world view, preconventional moral development, higher frequency of relational problems, psychotropic consumption and maladjusted behaviours.

Estimulación temprana: diez años de experiencia / Early stimulation: 10 years experience

El rendimiento psicomotor de los niños de bajo nivel socioeconómico se deteriora desde el primer año de vida. Esto implica a futuro una gran repercusión para el individuo, la familia y la sociedad. Los programas de estimulación temprana han demostrado mejorar el rendimiento psicomotor en los niños de bajo nivel socioeconómico. En los grupos de niños con diferentes riesgos, incorporados a un programa de estimulación temprana en Temuco, se puede apreciar que a menor peso de nacimiento hay mayor riesgo de deterioro psicomotor a futuro. Igual cosa se observa en los niños que presentaron meningitis neonatal. En cambio en los niños que presentaron hiperbilirrubinemia, Apgar bajo y septicemia neonatal no se observaron diferencias estadísticamente significativas comparados con niños de igual peso sin ese antecedente. Se comenta la necesidad de revisar el Programa de Evaluación y Estimulación Psicomotora del Ministerio de Salud de Chile, para adecuarlo a los niños que presentan un mayor riesgo y concentrar los recursos en ellos

Polyamine distribution among maize embryonic tissues and its relation to seed germination.

Polyamines are known to participate in the control of cell division. In the present report, the levels and distribution of polyamines in the embryonic tissues of maize seeds were studied to relate them to the reinitiation of cell division during seed germination. Results indicate higher contents of polyamines in scutellum than in axis tissues of dry seeds. After germination, larger increments of the three polyamines were obtained in axes, rather than in scutella. Seeds of low viability did not show putrescine increments after germination. It is suggested that spermidine and spermine are directly related to the germination process.