Anatomical variations of the circle of Willis in males and females on 3D MR angiograms

The objective of the present work was to study the anatomical variations of the circle of Willis as regard its component vessels and their average diameters in a sample of adult Egyptians and to detect any sex-related differences in these variations. One hundred and twenty adult patients were observed [60 males and 60 females]. They all had problems unrelated to any ischemic or vascular diseases, so they were considered as healthy control, concerning the morphology of the circle of Willis. In addition, ten cadavers' brains were obtained from the Anatomy department, Faculty of Medicine Ain Shams University for examination of the circle of Willis and for detection of any variations. The anatomical variations of the anterior part, posterior part and completeness of the circle were inspected. Also, the diameters of all component vessels were assessed. The results indicated that, the anterior part of the circle was completed in 70% males and 75% females of the study sample. No statistically significant difference was detected between sexes. The most common variant of the anterior part was the single anterior communicating artery followed by the hypoplastic or absent anterior communicating artery. The posterior part of the circle was completed in 48% males and 58% females. The most common variant was the bilateral posterior communicating arteries, followed by the unilateral posterior communicating artery. An entirely complete circle was found only in 45% of the entire population; and it was higher in the females than in males. The vessels diameters were smaller in the females than in the males, except for the diameter of the posterior communicating artery. Cadavers' examination revealed six cases with complete circle, 3 cases of unilateral fetal posterior communicating and one case of absent posterior communicating artery. The present study showed the amazing great variability of the anatomy of the circle of Willis in asymptomatic persons. Nevertheless, there were no marked differences between both sexes in most of the components and the mean diameters of the circle. Therefore, these anatomical variations have to be considered during radiological interpretation and would be reported in the current anatomy text to be aware of all these normal variations

experimental study of the effects of nicotine on the intervertebral disc

Clinically it had been noticed that a large proportion of patients presenting with low back pain are smokers. Therefore, in this experimental study the histological effects of nicotine on the lumbar intervertebral discs of the rabbits was investigated. Eighteen rabbits were divided equally into 3 groups, Group I [a and b]; as control. Group 2 injected intraperitoneally by 5000 ng/kg nicotine daily for 4 weeks. Group 3 injected intraperitoneally by 5000 ng/kg nicotine daily for 8 weeks. The selected dose produced blood nicotine levels equivalent to those found in heavy smokers [30 cigarettes / day]. Light and electron microscopic studies revealed that nicotine injection showed a variety of histological changes, which were not observed in the control group. This includes appearance of spaces within the nucleus pulposus and separation from the adjacent fibrous lamellae in the annulus fibrosus. Also loss of the regularity of the multilayered structure of the annulus fibrosus, and excessive inclusions associated with vacuoles which continue with the rough endoplasmic reticulum within the chondrocytes. Disc degeneration was more marked in rabbits injected with nicotine for 8 weeks [G3] than in those injected for 4 weeks [G2]. It could be concluded that the disc degeneration is more common among smokers and is correlated with the duration of exposure to nicotine

Protective effect of magnesium sulfate against radiation-induced heart damaged in albino rat

ability of Magnesium sulfate to reduce the severity of the late stage of radiation - induced heart disease [RIHD] was assessed in 40 white albino rats. Ten rats served as a control not exposed to radiation [cont.], another 10 rats were given only MgSo4 for 10 days as a negative control [-ve cont.]. The remaining rats were divided into two groups, group [A] ten animals exposed to a single dose of radiation [20 Gy]. Group [B] ten rats received MgSO4 [50 mg / kg intraperitoneally injected], 4 days prior to radiation, at the day of radiation and on the following 5 consecutive days. At 100 days post - radiation, the severity of the late state was determined by microscopic examination for myocardial fibrosis and by studying the ultrastructural changes. Irradiation found to have aggravated structured effect on the heart in the form of lysis and indistinct striation of muscle fibers, irregular pyknotic nuclei, depletion of glycogen granules and abnormal shaped mitochondiria. The adjacent cardiac muscle fibers were widely separated with marked congestion of the blood capillaries and interstitial cellular infiltration. Magnesium sulfate appeared to have protective effect in the form of reduction of myocardial of collagen content [fibrosis]. Suppression of the inflammation with preservation of the normal characters of most of the muscle fibers