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Morphological characteristics of styloid process evaluated by computerized axial tomography.

Morphological characteristics of styloid process and ossified stylohyoid ligament and their overall relationships to age and sex were studied by using computerized axial tomography images. The styloid process and ossified stylohyoid ligaments were classified into seven groups according to their shapes and lengths. The styloid process of a length of 25-40 mm, was the most frequently encountered. The elongated styloid process was mostly seen in males. There was no overall correlation between the types of SP and sex. The progressive increase in length with age was not seen in our study.

Common surgical pitfalls in the skull.

BACKGROUND A detailed knowledge of the morphologic variations in the ossicles, foramina, and ridges of the skull vault and skull base is vital to performing safe radical surgery. METHODS A surgical reminder of possible pitfalls was composed based on the incidences of most of the minor variations such as the supraorbital notch, frontal foramen, metopism, foramen caecum, parietal foramina, bony defects in the fossa occipitalis cerebellaris, Inca bone, foramen lacerum anterius, incomplete posterolateral wall of the foramen ovale, absence of the medial or posterior wall of the foramen spinosum, foramen innominatus, foramen meningoorbitale, bony dehiscence of the internal carotid canal, bony ridge or torus in the floor of the external auditory meatus, foramen of Huschke, precondylar tubercle, foramen hypoglossi, anterior condylar canal, hypoglossal bridging, divided articular surface of the occipital condyle, high jugular bulb, paramastoid process, atlanto-occipital assimilation, ossicle of Kerkring, delta or keyhole shaped bony defects in the anterior border of foramen magnum, foramen of Vesalius, posterior condylar canal, mastoid emissary foramen and occipital foramen in 200 skulls. CONCLUSION Recognition of these structures and their possible variations will help in distinguishing normal from potentially abnormal structures during computed tomography and magnetic resonance imaging examinations, and in avoiding misinterpretations that lead to confusion during surgical interventions. Instrumentation near potential bone gaps may traumatize important neural or vascular structures.

Effect of fresh and stored botulinum toxin a on muscle and nerve ultrastructure : An electron microscopic study

The aim of this study was to compare the ultrastructural alterations of the muscle and nerve that appear following injection of freshly reconstituted and stored botulinum toxin A. Fifteen New Zealand white rabbits were assigned to 6 groups, and anterior auricular muscle was used for injections. Group 1 did not receive any injection and group 2 received saline injection. Groups 3 and 5 received fresh botulinum; muscles and motor nerves were harvested at 5 days and 12 weeks, respectively. Groups 4 and 6 received stored botulinum; muscles and motor nerves were harvested at 5 days and 12 weeks, respectively. Alterations in muscle and nerve ultrastructure were evaluated with electron microscopy. Degeneration findings in muscle after botulinum toxin injection revealed no significant difference between freshly reconstituted and stored toxin in the early period. When stored toxin was used, atrophic changes in the muscle were less severe than the fresh toxin at 3 months. On nerve evaluation, fresh toxin displays significant acute changes on nerve ultrastructure; however, fresh and stored toxin shows similar degeneration at 12 weeks.

Dose-related immunohistochemical and ultrastructural changes after oral methylphenidate administration in cerebrum and cerebellum of the rat

Methylphenidate is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder of children and young adults. Our aim is to investigate dose-dependent dopamine-2 receptor and glial fibrillary acidic protein expression and ultrastructural changes of the rat brain, to demonstrate possible toxicity of the long-term and high dose use of the methylphenidate. In this study, 27 female prepubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) were treated orally with methylphenidate dissolved in saline solution for 5 days per week during 3 months. At the end of the third month, tissues were removed and sections were collected for immunohistochemical and ultrastructural studies. We believe that methylphenidate causes dose-related activation of the dopaminergic system in several brain regions especially in ventral tegmental area and also causing neuronal degeneration and capillary wall structural changes such as basal membrane thickness and augmentation of the pinostatic vesicle in the endothelial cells. Also, increased dose of Ritalin is inducing astrocytes hypertrophy especially astrogliosis in pia-glial membrane and this is the result of the degenerative changes in prefrontal cortex region due to high dose methylphenidate administration. The dose-related accumulation of the astrocytes in capillary wall might well be a consequence of the need for nutrition of the neuronal tissue, due to transport mechanism deficiency related to neuronal and vascular degeneration. Thus, we believe that the therapeutic dose of methylphenidate must be kept in minimum level to prevent ultrastructural changes.

Morphometric Study of a Horseshoe Kidney

Objective: To describe a horseshoe kidney, a congenital anomaly of the upper urinary tract. Clinical Presentation: A case study of horseshoe kidney harvested from a 62-year-old cadaver at Gazi University Medical School is presented. Results: The right and left kidneys were fused at their lower poles by a parenchymal isthmus located ventral to the abdominal aorta and formed a U-shape with two unequal arms.The isthmus of the ectopic kidney was placed obliquely to the left at the level of the fourth and fifth lumbar vertebra. The left kidney was larger and longer than the right one. The kidneys were supplied by three renal arteries arising from the abdominal aorta. Two arteries on the right side supplied blood of the two kidneys, while the third artery that directly originated from the aorta, above the origin of inferior mesenteric artery, supplied the isthmus. Venous drainage of the both kidneys and the isthmus were drained by three veins that opened independently into the inferior vena cava. The right ureter was duplicated in origin. Conclusion: This report shows that knowledge of anomalies such as this is very important in planning and conducting surgical procedures.

Age-Related Immunohistochemical and Ultrastructural Changes in Rat Oculomotor Nerve

During ageing process, multiple changes occur on nervous tissue composed of cells and extracellular matrix. Changes on nervous tissues are usually known as degenerative changes on axon structure and connective tissue covering the nerve such as a decrease in the number of fibre or general structural changes. For this purpose, we have studied age‐dependent ultrastructural changes in the rat oculomotor nerve with electron microscopy and also demonstrated collagen structure of the neural sheaths with immunohistochemical techniques. This study was conducted in Gazi University Faculty of Medicine, Department of Anatomy with a total of nine Wistar albino rats. We observed strong collagen type I immunoreactivity in endoneurium and slight to moderate reactivity in fibroblast cytoplasm in 3‐month‐ and 12‐month‐old groups and mild reactivity in 24‐month‐old group. Collagen type IV immunoreactivity was stronger in endoneurium and perineurium in the 3‐month‐ and 12‐month‐old groups compared with collagen type I and fibroblast cytoplasm showed a very strong reactivity. On the other hand, in the 24‐month‐old group, there was slight reactivity in endoneurium and a strong reactivity in perineurium. NGF staining showed moderate to strong reactivity on Schwann cells of the 3‐month‐old group. The immunoreactivity decreased in the 12‐month‐ and 24‐month‐old groups. In the 3‐month‐old rat group, Schwann cell cytoplasm, mitochondrial structure and neurofilaments were normal. In the 12‐month‐old group, there were no changes in organelle distribution, mitochondrial structure and neurofilaments, but there was an increase in the connective tissue. An inconsiderable number of degenerated myelinated nerves were observed. We detected an important decrease in the collagen type I immunoreactivity, which could suggest that the endoneurium, perineurium and epineurium are less resistant to the age‐related collagen loss and that the peripheral nerve is protected by a weaker barrier in the old group. The collagen type IV immunoreactivity was significantly decreased with age. NGF synthesis decreases with age because of Schwann cell structural degeneration or for different reasons. Thus, this could explain the diminished capacity of regeneration and damage of the myelination of the peripheral nerve.

Innervation of the Rat Anterior Abdominal Wall as Shown by Modified Sihler’s Stain

Objective: The purpose of this study was to use the modified Sihler’s staining technique to demonstrate detailed distribution of the rat anterior abdominal wall nerves and test the value of Sihler’s technique in demonstrating such a complex muscle-nerve relationship. Materials and Methods: The anterior abdominal walls of 5 Wistar rats were isolated by making a deep incision from the costal arches on each side down to the inguinal region and processed using a modified Sihler’s stain technique. Results: This technique was successfully applied to visualize the innervation of the anterior abdominal wall muscles of the rat. The segmental nerves of T6–L1 and their terminal branches were shown and possible motor and sensory fibers identified. Conclusions: This technique is valuable in understanding the complex nature of final branching of the nerve endings, and it may be useful for studying experimental nerve models.

Occipital Emissary Foramen in Skulls from Central Anatolia

In this study, a total of 125 female and 175 male adult human skulls from Central Anatolia were examined. The incidence and localization of the rate occipital foramen found on the squama of occipital bone were investigated. This foramen has significant importance during suboccipital craniotomies since it transmits the occipital emissary vein. In the present study, the occipital foramen was found in 8 (2.6%) skulls. Its location was closer to the foramen magnum but not to the external occipital protuberance.

Atrophic and Regenerative Changes in Rabbit Mimic Muscles after Lidocaine and Bupivacaine Application

Destruction and denervation atrophy in skeletal muscles caused by the injection of local anaesthetics was investigated by injecting lidocaine or bupivacaine around the rabbit facial nerve to produce facial paralysis. Animals were then sacrificed at 2, 4, 6, and 8 weeks post‐injection, and changes in mimic muscle tissue were assessed at each stage by light microscopy and electron microscopy. Atrophic changes were observed at 2–6 weeks after injection, and regeneration started at 6–8 weeks. Compared to bupivacaine, lidocaine caused more dramatic atrophic changes and was associated with slower muscle regeneration.

Dose‐Dependent Immunohistochemical and Ultrastructural Changes After Oral Methylphenidate Administration in Rat Heart Tissue

Methylphenidate, more commonly known as Ritalin, is a piperidine derivative and is the drug most often used to treat attention deficit/hyperactivity disorder, one of the most common behavioural disorders of children and young adults. Our aims were to investigate dose‐dependent immunohistochemical D2 expression and ultrastructural changes of the rat heart tissue, and to demonstrate possible toxicity of the long‐term and high dose use of the methylphenidate. In this study, 27 female pre‐pubertal Wistar albino rats, divided into three different dose groups (5, 10 and 20 mg/kg) and their control groups, were used. They were treated orally with methylphenidate dissolved in saline solution for 5 days/week during 3 months. At the end of the third month, after perfusion fixation, left ventricle of cardiac tissue was removed. Paraffin, semi‐thin and thin sections were collected and immunohistochemical, terminal deoxynucleotidyl transferase‐mediated Dig‐dUTP nick end labelling assay and ultrastructural studies were performed. In conclusion, we believe that Ritalin is dose‐related affecting dopaminergic system to increase heart rhythm and contraction. Thus, this drug may cause degenerative ultrastructural changes in mitochondrial path.