Reliability of physiology MCQs' examinations at the Faculty of Medicine, University of Khartoum

Background: One of the major challenges that face exam constructors is generating highly reliable exams. An assessment cannot be viewed as valid unless it is reliable. Test reliability, which is the best single measure of test accuracy, is the extent to which test results are consistent, stable, reproducible and free of error variance. Reliability isinfluenced by internal factors related to exam construction, as well as external factors which depend on the situation of test administration. Objective: To estimate the reliability of multiple choice questions (MCQs) of physiology exams as part of an overall quality assessment at the Faculty of Medicine, University of Khartoum.Methods:Reliability influential factors related to exam construction and administration were controlled and catered for by departmental and administrative staff according to the exam regulations of the faculty. Remark software was used for post-examination analysis of scores of ten consecutive summative physiology MCQ exams at the Faculty of Medicine, University of Khartoum. The number of the examinees who sat for each of the ten exams ranged from 332­359. In addition to reliability coefficients, item difficulty index (DIF I) and point-biserial correlation coefficient (rpbis)as a measure of item discrimination ability, were calculated as part of item analysis results.Results:The study revealed high exams' reliability (0.84-0.95) as measured by different formulas [Kuder-Richard-son Formulas (KR-20, KR-21) and Cronbach's-Alpha], and low standard error of measurement/SEM (3.073.80).Factorswhichcontributed to the high reliability of our ten exams were: their high discrimination power (0.32-0.47), their recommended mean difficulty (48.62-65.67%), and the relatively large numbers of items (60­80) per each exam.Conclusion:The high exams reliability of this study was an indicator of the precise control of external and internal factors influencing reliability. The most important contributing factor was the proper construction of exams with high quality items; in addition to careful exam administration and meticulous scoring system

Determinação da taxa metabólica basal em cutias, Dasyprocta azarae, por calorimetria indireta / Determination of the basal metabolic rate in agoutis, Dasyprocta azarae, by indirect calorimetry

A melhor ferramenta para comparação fisiológica entre organismos diferentes é a taxa metabólica basal, inter-relação fundamental que existe entre todos os seres vivos. Mensurações diretas das concentrações de oxigênio e dióxido de carbono, pela análise do ar inspirado e expirado, podem ser usadas para a mensuração de taxa metabólica. Este trabalho foi executado com o propósito de aferir as taxas metabólicas basal e específica, e reexaminar o escalonamento do metabolismo basal em cutias (Dasyprocta azarae). Foram utilizadas 34 cutias (D. azarae) adultas sadias, sendo 9 machos não castrados, 9 machos castrados e 16 fêmeas, pertencentes ao plantel do Criadouro Científico do Museu de História Natural Capão da Imbuia, Curitiba, PR. Os animais passaram por jejum prévio de 6 horas e foram acondicionados em caixas especiais, com temperatura ambiente controlada (22,0±1,0ºC), sendo então submetidos à aferição da taxa metabólica basal, por calorimetria indireta. Empregou-se o monitor metabólico Deltatrac®II, (Datex Ohmeda, Finlândia) usualmente indicado para a mensuração da produção de dióxido de carbono (VCO2) e do consumo de oxigênio (VO2) em seres humanos, por meio da mensuração das variações na concentração de VCO2 e de VO2, com uma precisão de 0,01 por cento. Após a aferição da taxa metabólica basal, foi calculada a taxa metabólica específica, e efetuada a análise dos dados por estatística indutiva. Os testes de hipóteses para comparação entre amostras indicaram que a taxa metabólica específica de machos não castrados é maior que a de fêmeas e machos castrados (5 por cento de significância), e que a taxa metabólica específica de fêmeas e machos castrados é equivalente (1 por cento de significância). Constatou-se ainda, com a análise da correlação de pontos experimentais, que outra variável que não o tamanho corporal afeta a taxa metabólica dos machos não castrados (1 por cento de significância), o que indica a necessidade de novos estudos sobre...

The best way to compare different organisms is the basal metabolic rate, a fundamental interrelation existent among all living beings. Direct measures of oxygen and carbon dioxide concentrations by evaluation of inspired and expired air can be used to measure metabolic rate. So, this research was done in order to measure basal and specific metabolic rates in agoutis (Dasyprocta azarae), and reexamine the scaling of basal metabolism in this species. There were used 34 adult healthy agoutis (9 non-castrated males, 9 castrated males, and 16 females), that belong to the wild animal scientific breeding facility of the Natural History Museum of the Curitiba city, State of Paraná, Brazil. After a six-hour fasting the animals were placed in special boxes under controlled temperature (22.0±1.0ºC), and submitted to measuring of the basal metabolic rate, by indirect calorimetry. It was used the Deltatrac®II metabolic monitor, usually indicated to measure carbon dioxide production (VCO2) and oxygen consumption (VO2) in human beings, by measuring variations in the concentration of VCO2 and of VO2, with a precision of 0.01 percent. The specific metabolic rate was calculated after determination of the basal metabolic rate and the obtained data were analyzed by inductive statistics. The hypotheses tests for comparison among samples indicated that the specific metabolic rate is higher in non-castrated males than in females and castrated males (significance of 5 percent), and that the specific metabolic rate of females and castrated males are equivalent (significance of 1 percent). In addition, analysis of the correlation of experimental points indicates that another variable beyond body size affects the metabolic rate of non-castrated males (significance of 1 percent), and therefore new studies on the metabolism of Dasyprocta azarae are required.

Comparative in vitro antioxidant potential of different parts of Ipomoea asarifolia, Roemer & Schultes, Guiera senegalensis, J. F. Gmel and Anisopus mannii N. E. Brown

In this study, the radical scavenging capacity of Guiera senegalensis, Ipomoea asarifolia and Anisopus mannii were compared. The ascorbic acid equivalent of the stem bark (2.1 mM), leaves (2.05 mM) and root barks (1.89 mM) of Guiera senegalesis are much higher than any part of Ipomoea asarifolia or Anisopus manii. The stem bark, leaves and root bark of Guiera Senegalensis had IC50 of 15.4, 20.0 and 17.0 µL respectively, while corresponding parts of Ipomoea asarifolia showed IC50 of 50, 42 and 65 µL, respectively. These results suggest that Guiera senegalensis and Ipomoea asarifolia possess significant antioxidant capacities to warrant further detailed studies on the role of this property in their therapeutic effects.

Comparou-se a capacidade de sequestrar radicais livres de Guiera senegalensis, Ipomoea asarifolia e Anisopus mannii. O equivalente em ácido ascórbico da casca do caule (2,1 mM), folhas (2,05 mM) e da casca da raiz (1,89 mM) de Guiera senegalesis foi muito mais alto do que qualquer parte da Ipomoea asarifolia e da Anisopus manii. A casca do caule, as folhas e a casca da raiz de Guiera senegalensis apresentaram IC50 de 15,4, 20,0 and 17,0 µLl, respectivamente, enquanto as partes correspondentes de Ipomoea asarifolia apresentaram IC50 de 50, 42 e 65 µL respectivamente. Esses resultados sugerem que Guiera senegalensis e Ipomoea asarifolia possuem capacidade oxidante significativa que demanda estudos posteriores detalhados acerca do papel dessa propriedade em seus efeitos terapêuticos.

Comparative study for some physiological parameters in the three species of the snakes from different regions of Egypt during the hibernation

The aim of this study was to compare some physiological parameters in three species of snakes [Psammophis schokari aegyptius [from Aswan], Psammophis schokari schokari [from Al-Wahat] and Psammophis sibilans sibilans [from Mansoura]] during the winter. Physiological parameters including thyroid hormones [T3 and T4], thyroid stimulating hormone [TSH], insulin hormone, calcium, iron, sodium, potassium and cholesterol, were recorded in the three species of the snakes. The results showed that serum TSH, T4, insulin hormones and iron were lower in the serum of Psammophis schokari aegyptius than the other two species. Conversely, all other parameters, i.e. T3, Na, K and calcium increased significantly in the serum of Psammophis schokari aegyptius than in the other species. On the other hand, a higher level of cholesterol was found in the serum of Psammophis schokari schokari than that in the other two species. Level of cholesterol in the serum of Psammophis sibilans sibilans was lower than the other two species

Ley de la superficie e indexación alométrica de diversas funciones / Surface law and allometric analysis of several functions

Since Rubner stablished in 1883 the surface law, the basal metabolic rate (kcal/24h) is expressed per square meter of body surface. This so-called biological law has been extrapolated to the standarization of several other functions as, for instance, to variables of the cardiovascular, respiratory and renal systems, which may lead to erroneous conclusions. The present paper is an attempt to establish, by means of the dimentional analysis and one of the theories of biological similarity, an allometric indexation procedure, which yields mass-independent numbers (MIN) for all functions which can be defined by means of the MLT system of physics (Mass; Length; Time)

Glicose-6-fosfato desidrogenase e 6-fosfogliconato desidrogenase: atividade e cinética em condiçöes fisiológicas / Glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase: activity and kinetic in physiological conditions

Foram determinadas as atividades enzimaticas da G-6-PDG aos seus substratos G-6-P e 6-PGA respectivamente, em sistemas reagentes recomendados pela OMS e em condiçöes próximas às fisiológicas intraeritrocitárias de pH, temperatura, força iônica, e concentraçäo de moduladores, de indivíduos normais portadores das variantes G-6-PDB e G-6-PDA + e indivíduos deficientes de G-6-PD variante G-6-PDA -, para se estabelecer comparaçöes

Umbral del dolor a diferentes altitudes en ratones (Mus musculus)

Los misteriosos aspectos del dolor, demustran la complejidad de la definición de este fenómeno. Las áreas de gran altura representan un factor importante en la modificación de órganos, sistemas y funciones. El objetivo del presente estudio es evaluar la influencia de los factores propios de las grandes altitudes sobre el umbral del dolor. En un estudio experimental, autocontrolado, de elección deliberada; para la cual se utilizaron 50 ratones (Mus musculus), a quienes se les tomó Tiempos Análogos Umbrales del Dolor (TAUD) en Arequipa (2363 msnm), en una oportunidad (basales), y durante su exposición en Pampa Cañaguas (4142 msnm) y Mollendo (26 msnm) evaluaciones cada 8 horas durante 2 días. Se empleó el método modificado de D'Amour, cuyo estímulo térmico está representada por agua a 40ºC constante, donde el tiempo (centésimas de segundo) de permanencia de la cola del animal en el estímulo es determinada como TAUD. Tales evaluaciones fueron realizadas en laboratorios a temperatura y humedad constantes. Se obtuvo el valor basal TAUD de 1938.4 cseg. (DE_895.1). Los valores obtenidos en Pampa Cañaguas (8 Hs: X=1485.7, DE=849.1; 16 Hs: X=2757.8, DE=1380.1; 24 Hs: X= 2620.1, DE=1728.1; 32 Hs: X=3759.6, DE=1726.1; 40 Hs: X=4051.2, DE=1930.9; 48 Hs: X=3866.3, DE=1853.2) son menores en relación a los obtenidos en Mollendo (8 Hs: X=3105.2, DE=1178.2; 16 Hs: X=2336.6, DE=994.0; 24 Hs: X=2176.0, DE= 1124.5; 32 Hs: X=1988.0, DE=830.6; 40 Hs: X=2077.2, DE=853.3; 48 Hs: X=1982, DE=810.0), donde el ANOVA, en la linea de efectos principales para tiempo de exposición indica F=3.961 (P=0.0016), así mismo en la línea de efectos para grupo indica F=69.196 (P<0.0001), ambos resultados estadísticamente significativos. La interacción entre el tiempo de exposición y lugar de exposición (que refleja la altitud) es además estadísticamente importante (F=23.3; p<0.0001). Los resultados obtenidos sugieren que el umbral del dolor disminuye durante la exposición a áreas de gran altura. Se ameritan estudios posteriores, con diferentes métodos y diseños así como su estudio en seres humanos

Respuestas fisiológicas en el proceso de aclimatación al calor / Physiologic responses in heat acclimatization process

Se les aplicaron a un total de 10 trabajadores, nunca antes expuestos al calor industrial, cargas submáximas de trabajo en una bicicleta ergométrica, en 2 locales cuyas condiciones climáticas eran muy diferentes y se podían definir como calurosas y no calurosas. Se les registraron a todos los casos, durante el reposo y la actividad, la frecuencia cardíaca (FC), el volumen-minuto respiratorio (VMR), la temperatura oral y la tensión arterial, midiéndose además la sudación horaria en cada día de exposición al calor. Se aplicó la carga submáxima en 3 ocasiones por un solo día en el local no caluroso y durante 6 días sucesivos en el local caluroso. Se compararon las respuestas fisiológicas de estos casos en las condiciones de calor con las registradas en las condiciones no calurosas. Se encontró que a partir del cuarto día de exposición, la FC y la sudación disminuyeron e incrementaron sus valores respectivamente hasta cifras significativas de adaptación al calor