The effects of progesterone on hypoxic ischemic injuries in the Cornu Ammonis (CA) region of the hippocampus of neonatal rats / Efectos de la progesterona en lesiones por hipoxia isquémica en la región Cornu Ammonis (CA) del hipocampo en ratas neonatas

Hypoxia-ischemia (HI) is a major cause of brain damage in the newborn. Several studies elicited the neuroprotective effects of progesterone in adult rats but there is very little literature available on neonatal rats. Therefore the present study is undertaken to see the effect of progesterone in hypoxic ischemic brain injury in neonatal rats, using an established neonatal HI rat pup model. Seven-day-old rat pups were subjected to right common carotid artery ligation and then 60 minutes hypoxia. The first dose of progesterone to treatment group was administered by peritoneal injection (4 mg/kg), after 10 minutes of exposure and subsequent doses were given by subcutaneous injection at 6 h, 24 h and 48 h intervals. Control group was also exposed to HI and was given only the vehicle (peanut oil) through the same route and intervals as that of treatment group. After 96 h, the pups were perfused with 10% formalin and brains were sampled and stained with toluidine blue. Cells density and number of pyramidal cells of the hippocampal Cornu Ammonis (CA) regions were examined by stereological methods. The histomorphometric assessment of the effects of progesterone showed minimal but no significant protective value in the volume, cells density and total number of pyramidal cells of hippocampal CA region of the treatment and control groups (p>0.05) after HI. Our results concluded that 4 mg/kg of PROG had no significant neuroprotective effect in HI model of the neonatal rat's hippocampus.

La hipoxia-isquémica (HI) es una causa importante de daño cerebral en el recién nacido. Varios estudios indican los efectos neuroprotectores de la progesterona en ratas adultas, sin embargo existe poca literatura disponible en ratas recién nacidas. Por tanto, el presente estudio se llevó a cabo para ver el efecto de la progesterona en la lesión cerebral HI en ratas recién nacidas, utilizando un modelo de cría de rata neonata HI establecido. A los siete días de nacidas, las crías de ratas fueron sometidas a la ligadura de la arteria carótida común derecha y luego 60 minutos de hipoxia. La primera dosis de progesterona fue administrada al grupo de tratamiento mediante inyección peritoneal (4 mg/kg), después de 10 minutos de exposición y las dosis posteriores fueron administradas por inyecciones subcutáneas en intervalos de 6 h, 24 h y 48 h. El grupo control también fue expuesto a HI y se le administró solamente aceite de cacahuete a través de la misma ruta y con los intervalos que recibió el grupo de tratamiento. Después de 96 h, las crias fueron perfundidas con formalina al 10% y se tomaron muestras de los cerebros, los que se tiñeron con azul de toluidina. La densidad celular y el número de células piramidales de las regiones del hipocampo Cornu Ammonis (CA) fueron examinadas por métodos estereológicos. La evaluación histomorfométrica de los efectos de la progesterona mostró un valor protector mínimo, pero no significativo en el volumen, densidad de las células y el número total de células piramidales de la región de CA del hipocampo de los grupos de tratamiento y control (p>0,05) después de HI. En conclusión, nuestros resultados indican que 4 mg/kg de progesterona no tuvo efecto neuroprotector significativo en el modelo de HI del hipocampo de ratas neonatas.

Interparietal bone variations in accordance with their ossification centres in human skulls / Variaciones de los huesos interparietales de acuerdo con sus centros de osificación en cráneos humanos

The upper interparietal segment of the squamous part of the occipital bone develops in membrane and the lower supraoccipital part develops in cartilage. According to the available literature, the interparietal segment is ossified from 2 to 3 pairs of ossification centres and each of these centres has 2 nuclei. Interparietal bone is formed due to failure of fusion of these centres and/or their nuclei with each other. Many variations of interparietal bone have been reported by many investigators. In the present study, out of 25 human skulls studied, six skulls had some interesting variations of interparietal bones. Four interparietal bones were found in one skull, 2 interparietal bones were observed in another skull and the remaining four skulls had a single interparietal (Os inca) bone at the lambda. In addition to interparietal bones, some sutural bones were also observed in three skulls. These variations were in accordance with the ossification centres of the membranous part of the occipital bone. By their location and shape it was concluded that they were formed due to failure of fusion of nuclei of the third pair centres of ossification with each other, with opposite fellow and with the second pair centers. It was further concluded that these cases of interparietal bones were different from what had been reported earlier by other researchers and this prompted the present report that may be found useful for anatomists, anthropologists, radiologists and neurosurgeons.

El segmento interparietal superior de la porción escamosa del hueso occipital es de origen membranoso y la parte inferior supraoccipital se desarrolla en el cartílago. De acuerdo con la literatura disponible, el segmento interparietal se osifica a partir de 2 a3 pares de centros y cada uno de estos centros cuenta con 2 núcleos. El hueso interparietal se forma debido a la falta de fusión de estos centros y / o sus núcleos. Muchas variaciones de hueso interparietal han sido reportados por investigadores. En el presente estudio, de 25 cráneos humanos estudiados, seis cráneos presentaban algunas variaciones interesantes de huesos interparietales. Cuatro huesos interparietales fueron encontrados en un cráneo, dos huesos interparietales en un cráneo y cuatro cráneos presentaban un solo hueso interparietal (Os inca) en el lambda. Además, de los huesos interparietales, en tres cráneos se observaron huesos suturales. Estas variaciones estaban en relación con los centros de osificación de la parte membranosa del hueso occipital. Por su ubicación y forma, se concluyó que los huesos se formaron debido a la falta de fusión entre sí de los núcleos de los centros del tercer par de osificación, con otros opuestos y con los centros del segundo par. Se concluye, además, que estos casos de huesos interparietales eran diferentes de lo que se había informado anteriormente por otros investigadores y esto nos impulsó al estudio, el cual puede ser útil para anatomistas, antropólogos, radiólogos y neurocirujanos.

Evaluation of the protective effects of tocotrienol-rich fraction from palm oil on the dentate gyrus following chronic restraint stress in rats

Exposure to chronic restraint stress has been shown to cause a number of morphological changes in the hippocampal formation of rats. Tocotrienol, an isoform of vitamin E, exhibits numerous health benefits, different from those of tocopherol. Recent studies have demonstrated that tocotrienol prevents stress-induced changes in the gastric mucosa, thus indicating that it may also protect other organs such as the brain from the damaging effects of stress. Therefore, the aim of the present study was to investigate the protective effect of tocotrienol-rich fraction (TRF) extracted from palm oil on the dentate gyrus of rats following exposure to chronic restraint stress. Thirty-six male Sprague Dawley rats were divided into four groups: control, stress, tocotrienol and combination of stress and tocotrienol. Animals were stressed by restraining them for 5 hours every day for 21 consecutive days. TRF was administered via oral gavage at a dose of 200 mg/kg body weight. Our results showed that the plasma corticosterone level was significantly increased in response to stress, compared to the control. The results confirmed previous findings that chronic restraint stress suppresses cellular proliferation and reduces granule cell number in the dentate gyrus. However, TRF supplementation failed to prevent or minimize these stress-induced changes. Therefore, we conclude that TRF at the current dosage is not effective in preventing the morphological changes in the dentate gyrus induced by chronic restraint stress.

A exposição crônica ao estresse por restrição causa série de alterações morfológicas na formação do hipocampo de ratos. Tocotrienol, uma isoforma da vitamina E, apresenta inúmeros benefícios para a saúde, diferente do tocoferol. Estudos recentes demonstraram que o tocotrienol impediu alterações induzidas por estresse na mucosa gástrica, indicando, assim, a possibilidade de que ele pode, também, proteger outros órgãos, como o cérebro, dos efeitos nocivos do estresse. Dessa forma, o objetivo do presente estudo foi investigar o efeito protetor da fração rica em tocotrienol (TRF), extraída do óleo de palma, no giro denteado após exposição crônica ao estresse por restrição. Trinta e seis ratos machos Sprague Dawley foram divididos em quatro grupos: controle, estresse, tocotrienol e combinação de estresse e tocotrienol. Os animais foram estressados por restrição, 5 horas por dia, durante 21 dias consecutivos. TRF foi administrado por gavagem oral na dose de 200 mg/kg de peso corporal. Nossos resultados mostraram que o nível de corticosterona plasmática foi significativamente aumentado em resposta ao estresse em comparação ao controle. Os resultados confirmam os achados anteriores de que o estresse por restrição suprime a proliferação celular e reduz o número de células granulares do giro denteado. No entanto, a suplementação de TRF foi ineficaz para evitar ou minimizar as alterações induzidas por estresse. Assim, concluímos que TRF na dose corrente não é efetiva para prevenir as alterações morfológicas no giro denteado induzida por estresse crônico por restrição.

Anatomic variants of foramen ovale and spinosum in human skulls / Variantes anatómicas de los forámenes oval y espinoso en cráneos humanos

Foramen ovale and spinosum are important foramina of the greater wing of the sphenoid. Normal variations in their shapes and sizes are quite common and widely studied. In the present study, conducted in the Department of Anatomy of School of Medical Sciences, Universiti Sains Malaysia, 25 dried human skulls were examined for anatomic variations of the foramina of the greater wing of the sphenoid. During the study, we noticed anatomic variations of the foramen ovale and spinosum. In one skull, there was an abnormally large and irregular foramen ovale which was confluent with the foramen spinosum. In the second skull, the foramen spinosum was absent on the left side and in the 3rd skull it was duplicated on the right side. These variations are very rare and may be of clinical and anatomical significance to neurosurgeons and physicians particularly in cases of trigeminal neuralgia, diagnostic detection of vascular tumors and aneurysm.

Los forámenes oval y espinoso son forámenes importantes del ala mayor del esfenoides. Variaciones normales en sus formas y tamaños son muy comunes y ampliamente estudiados. En el presente repórter, llevado a cabo en el Departamento de Anatomía de la Facultad de Ciencias Médicas, Universiti Sains Malaysia, fueron examinados en 25 cráneos humanos secos las variaciones anatómicas de los forámenes del ala mayor del esfenoides. Durante el estudio, se observaron algunas variaciones anatómicas de los forámenes oval y espinoso. En un cráneo, se observó un foramen oval anormalmente grande e irregular, que era confluente con el foramen espinoso. En el segundo cráneo, el foramen espinoso estaba ausente en el lado izquierdo y en el tercer cráneo se duplicó en el lado derecho. Estas variaciones son muy raras y pueden ser de importancia clínica y anatómica para neurocirujanos y médicos, en particular en casos de neuralgia del trigémino, detección diagnóstica de tumores vasculares y aneurismas.