Medullary branches of the vertebral artery: microsurgical anatomy and clinical significance.

BACKGROUND: Since the medullary arteries are of a great neurologic and neurosurgical significance, the aim was to perform a detailed microanatomic study of these vessels, as well as of the medullary infarctions in a group of patients. METHODS: The arteries of 26 halves of the brain stem were injected with India ink and gelatin, microdissected and measured with an ocular micrometer. Neurologic and magnetic resonance imaging (MRI) examinations were performed in 11 patients. RESULTS: The perforating medullary arteries, averaging 6.7 in number and 0.26 mm in diameter, most often originated from the anterior spinal artery (ASA), and rarely from the vertebral (VA) (38.5%) and the basilar artery (BA) (11.6%). They supplied the medial medullary region. The anterolateral arteries, 4.8 in number and 0.2 mm in size, most often arose from the ASA and PerfAs, and nourished the anterolateral region. The lateral arteries, 2.2 in number and 0.31 mm in diameter, usually originated from the VA and the posterior inferior cerebellar artery (PICA). They supplied the lateral medullary region. The dorsal arteries, which mainly arose from the PICA and the posterior spinal artery (PSA), nourished the dorsal region, including the roof of the 4th ventricle. The anastomotic channels, averaging 0.3 mm in size, were noted in 42.3%. Among the medullary infarctions, the lateral ones were most frequently present (72.8%). CONCLUSION: The obtained anatomic data, which can explain the medullary infarctions symptomatology, are also important in order to avoid damage to the medullary arteries during neurosurgical and neuroradiologic interventions.

Examination of Shape Variation of the Skull in British Shorthair, Scottish Fold, and Van Cats.

A variety of skull shapes are frequently used for discrimination between animal species, breeds, and sexes. In this study, skulls of three different breeds of cats were examined by the geometric morphometric method, with the aim of revealing skull shape differences. For this purpose, 27 cats (6 British Shorthair, 7 Scottish Fold, and 14 Van cats) were used. The skulls of cats were modeled by computed tomography. Geometric morphometrics was applied using dorsal (8 landmarks, 63 semilandmarks) and lateral (8 landmarks, 63 semilandmarks) skull projections on these models. Centroid size differences between the breeds were statistically insignificant. However, the differences in shape were statistically significant for both the dorsal view and lateral view. Shape variation was less in the British Shorthair than in other breeds. Shape differences generally occurred around the orbit. In the skull of Scottish Folds, the orbit was situated more caudally than in other breeds. The British Shorthair had the largest orbital ring. In dorsal view, the Scottish Fold had the largest orbital diameter. The orbital ring of Van cats was smallest in both dorsal and lateral views. In the canonical variate analysis, it was seen that the breeds were separated from each other. The shape difference in the skull between different cat breeds could be revealed by geometric morphometrics. The results of this study provide useful information for taxonomy.

Morphological and Morphometrical Aspects of the Auditory Ossicles in the European Badger (Meles Meles).

Given the scarce morphological data regarding the middle ear anatomy of this species, the paper attempts to describe the morphological and morphometrical data of the auditory ossicles in the badger. The study was performed using the standard morphological investigations and provides a complete morphological description of the ossicular assembly (malleus, incus and stapes) with some comparative features and attempts to provide a complete set of standardized metrical data for each ossicle. A more-detailed attempt to compare some functional aspects in the light of combined metrical ratios is also implied.

Anatomic and MRI bases for medullary infarctions with patients' presentation.

OBJECTIVE: There is a low incidence of the medullary infarctions and sparse data about the vascular territories, as well as a correlation among the anatomic, magnetic resonance imaging (MRI) and neurologic signs. MATERIALS AND METHODS: Arteries of the 10 right and left sides of the brain stem were injected with India ink, fixed in formalin and microdissected. The enrolled 34 patients with medullary infarctions underwent a neurologic, MRI and Doppler examination. RESULTS: Four types of the infarctions were distinguished according to the involved vascular territories. The isolated medial medullary infarctions (MMIs) were present in 14.7%. The complete MMIs comprised one bilateral infarction (2.9%), whilst the incomplete and partial MMIs were observed in 5.9% and 8.9%, respectively. The anterolateral infarctions (ALMIs) were very rare (2.9%). The complete and incomplete lateral infarctions (LMIs), noted in 35.3%, comprised 11.8% and 23.6%, respectively, that is, the anterior (5.9%), posterior (8.9%), deep (2.9%), and peripheral (5.9%). Dorsal ischemic lesions (DMIs) occurred in 11.8%, either as a complete (2.9%), or isolated lateral (5.9%) or medial infarctions (2.9%). The remaining ischemic regions belonged to various combined infarctions of the MMI, ALMI, LMI and DMI (35.3%). The infarctions most often affected the upper medulla (47.1%), middle (11.8%), or both (29.5%). Several motor and sensory signs were manifested following infarctions, including vestibular, cerebellar, ocular, sympathetic, respiratory and auditory symptoms. CONCLUSIONS: There was a good correlation among the vascular territories, MRI ischemia features, and neurologic findings regarding the medullary infarctions.

Fatal intussusception in infancy: forensic implications.

Intussusception is one of the most common causes of intestinal obstructions in younger children, especially infants. Though rare, fatalities due to intussusception are known to be caused by intestinal obstruction associated with peritonitis, generalized sepsis and shock from intestinal infarction due to disruption in blood supply or electrolyte and fluid imbalance. An eight-month-old female infant, who initially presented with a single episode of vomiting and fever (37.8 °C), was examined as an outpatient at the department of pediatrics of a general hospital. Clinical examination revealed no characteristic features of acute abdomen, so the child was sent home. Nine to ten hours later her condition deteriorated: she became hyperpyretic and stuporous. On her way to the University Children's Hospital, the infant died; the death was confirmed upon admission, i.e. some 15 h after the onset of symptoms. The autopsy revealed an 8 cm long intussusception of the distal part of the ileum to the cecum. There was no gross or microscopic evidence of peritonitis at autopsy. The shock caused by intestinal obstruction with consequent intestinal necrosis was considered to be the cause of death.

Anatomical and histological characteristics of the lungs in the ground squirrel (Spermophilus citellus).

The aim of this work was to study the topography, morphology, vascularisation, histology and innervation of the lungs in the ground squirrel (Spermophilus citellus) and compare these data with those concerning the rat, mole rat, rabbit and mouse. The research was carried out on 15 animals. It was revealed that the right lung has four lobes (cranial, middle, caudal and accessory lobes), while the left lung is not divided into segments. The functional vessels are a. pulmonalis dextra et sinistra and vv. pulmonales (5-6), while the nutritive vessels of the lungs are a. bronchoesophagea dextra and v. bronchoesophagea dextra. Histological tissue sections of the lungs revealed that the wall of terminal bronchioles contains no cartilage and the mucosal epithelium is pseudostratified, cubic and ciliated. Clara cells (club cells, bronchiolar exocrine cells) are present but have no cilia. The lung alveolar diameter is 37 µm on average, and the thickness of the alveolar wall and the interalveolar septa is 1.38 µm. Destruction of the alveolar walls, accumulation of erythrocytes in the capillaries of alveolar septa and destruction of the cytolemma of the capillary endothelium were detected. In addition, connective tissue fibres and peripheral nerves were detected by silver impregnation.

Phenylephrine preconditioning in embryonic heart H9c2 cells is mediated by up-regulation of SUR2B/Kir6.2: A first evidence for functional role of SUR2B in sarcolemmal KATP channels and cardioprotection.

ATP-sensitive K(+) (KATP) channels were originally described in cardiomyocytes, where physiological levels of intracellular ATP keep them in a closed state. Structurally, these channels are composed of pore-forming inward rectifier, Kir6.1 or Kir6.2, and a regulatory, ATP-binding subunit, SUR1, SUR2A or SUR2B. SUR1 and Kir6.2 form pancreatic type of KATP channels, SUR2A and Kir6.2 form cardiac type of KATP channels, SUR2B and Kir6.1 form vascular smooth muscle type of KATP channels. The presence of SUR2B has been described in cardiomyocytes, but its functional significance and role has remained unknown. Pretreatment with phenylephrine (100nM) for 24h increased mRNA levels of SUR2B and Kir6.2, without affecting those levels of SUR1, SUR2A and Kir6.1 in embryonic heart H9c2 cells. Such increase was associated with increased K(+) current through KATP channels and Kir6.2/SUR2B protein complexes as revealed by whole cell patch clamp electrophysiology and immunoprecipitation/Western blotting respectively. Pretreatment with phenylephrine (100nM) generated a cellular phenotype that acquired resistance to chemical hypoxia induced by 2,4-dinitrophenol (DNP; 10mM), which was accompanied by increased in K(+) current in response to DNP (10mM). Cytoprotection afforded by phenylephrine (100nM) was abolished by infection of H9c2 cells with adenovirus containing Kir6.2AFA, a mutant form of Kir6.2 with largely reduced K(+) conductance. Taking all together, the present findings demonstrate that the activation of α1-adrenoceptors up-regulates SUR2B/Kir6.2 to confer cardioprotection. This is the first account of possible physiological role of SUR2B in cardiomyocytes.

Lack of clastogenic effects of L-thyroxine in whole-blood cultured human lymphocytes

Thyroid hormones stimulate aerobic metabolism which may lead to oxidative stress accompanied by damage to various cellular macromolecules, including DNA. Previous comet assay studies have shown that thyroid hormones cause DNA damage due to the creation of reactive oxygen species (ROS). However, cytogenetic studies have been equivocal because although an increase in the sister-chromatid exchange frequency per cell has been reported increased micronuclei frequency has not. We used cytogenetic examination of chromosome breakage and aberrations in whole-blood cultures of human peripheral blood lymphocytes to investigate possible clastogenic effects when lymphocytes were exposed to 0.002 µM to 50 µM of L-thyroxine for 24 h and 48 h, these concentrations being chosen because they had been used in previous studies of sister-chromatid exchange and micronuclei frequency. Under our experimental conditions thyroxine did not induced any statistically significant increase in chromosome breakage or aberrations. This lack of clastogenic effects is in contrast to the reported comet assay results obtained using purified lymphocytes, possibly because whole-blood cultures contain catalase and glutathione peroxidase capable of reducing the effects of reactive oxygen species.