Anatomy of the Human Osseous Spiral Lamina and Cochlear Partition Bridge: Relevance for Cochlear Partition Motion

Journal of the Association for Research in Otolaryngology - The classic view of cochlear partition (CP) motion, generalized to be for all mammals, was derived from basal-turn measurements in...     

Reaction of rabbit lateral periventricular tissue to shunt tubing implants

The reaction of the periventricular tissue of the lateral ventricle to silicone rubber shunt tubing was studied by scanning and transmission electron microscopy. Nonfunctioning shunt tubing was implanted bilaterally into the frontal horns of rabbits, which were then sacrificed at postoperative intervals of 3 days to 16 weeks. Colchicine was used to study mitotic activity at the 3-day to 4-week postimplantation intervals. Reactive changes that occurred in the periventricular tissue correlated with the degree of contact with the implant and also with the duration of the postoperative period. Ependymal cells underwent progressive attenuation and sloughed completely in the most severely affected areas. Prominent gliosis in the subependyma accompanied the ependymal changes. The ventricular surface directly adjacent to holes in the implant developed ependyma-covered glial evaginations which grew into the implant holes beginning 1 week postimplantation. In the region of the outgrowths, ependymal mitotic activity was significantly increased at 1 and 2 weeks postimplantation. and astroglial mitotic activity was increased at 3 days and 1 week. Proliferation of ependymal and glial cells in the area touching the shunt tubing and mechanical factors contributed to the development of cellular outgrowths which may be a factor in the pathogenesis of shunt obstruction in human hydrocephalus.     

A relapse of paratyphoid fever after treatment with ciprofloxacin in a child with congenital biliary atresia

This report describes a relapse of Salmonella paratyphi B infection in a child with biliary atresia, following 2 weeks of treatment with ciprofloxacin. The recrudescence was complicated by the development of osteomyelitis and was treated with chloramphenicol, trimethoprim, ceftriaxone and ampicillin in succession.     

雌二醇对动情间期切除卵巢母羊黄体生成素分泌脉冲的抑制作用

动情间期母羊切除卵巢并皮下植入持续释放的E_2后,平均LH基础分泌水平和LH脉冲幅高比对照组显著减低,LH脉冲频率无明显改变。LH的平均基础分泌水平和脉?中幅高显著相关。表明植入E_2对垂体LH分泌的抑制作用主要是抑制LH对GnRH的反应,作用部位在垂体,不在下丘脑。LH基础分泌水平的下降,亦可能是E_2的抑制作用所致。     

The Asp84Glu variant of the melanocortin 1 receptor (MC1R) is associated with melanoma

Melanocyte stimulating hormone (MSH) plays an important role in determining the cutaneous response to ultraviolet radiation and may also influence melanoma progression. We have previously shown that variants of the melanocortin receptor present on melanocytes, MC1R, are associated with sun sensitivity and red hair in a UK population and therefore now consider the gene as a candidate for melanoma susceptibility. We have compared the frequency of known MC1R variants in the second and seventh transmembrane domains in 43 melanoma cases and 44 controls. MC1R variants were more common in cases than controls (chi 2 = 6.75, 1 d.f.; P = 0.0094) with a relative risk to carriers of variant alleles compared with normal homozygotes of 3.91 (95% c.l.: 1.48-10.35), and a population risk attributable to carriers of 34.6% (95% c.i. 10.7-52.1%). The Asp84Glu variant was only present in melanoma cases and appears to be of particular significance. The contribution of variant MC1R alleles was largely independent of skin type. Variants of the MC1R gene are likely to be causally associated with the development of melanoma.      

Morphology of astroglia in colony cultures following transient exposure to potassium ion, hypo?smolarity and vasopressin

Summary Brain swelling is the major cause of delayed neuronal damage following injury to the central nervous system. Swelling of mouse astroglial cells was studied in colony cultures by light and electron microscopy. Swelling of suspended astroglial cells was studied by flow cytometry. Swelling caused by hypoösmolar solution was more pronounced than that caused by 15 or 60mm K⁺. Under both conditions swelling in both immature and mature astroglia was followed by a regulatory volume decrease. Arginine vasopressin caused mild astroglial swelling and atrial natriuretic peptide did not significantly affect cell volume. All changes in extracellular environment were associated with changes in the morphology of microvilli and varying amounts of membrane ruffling. Immature cells exhibited a delayed response to the application of atrial natriuretic peptide and less membrane ruffling following exposure to 60mm K⁺ than mature astroglia. These nonspecific morphological changes are likely associated with changes in membrane ion pump activity.     

Reaction of periventricular tissue in the rat fourth ventricle to chronically placed shunt tubing implants

The reaction of periventricular tissue to shunt tubing chronically implanted in the fourth ventricle of the rat was investigated by correlative scanning and transmission electron microscopy. Sterile silicone tubing with four 0.4 mm diameter holes was inserted into the fourth ventricle of adult Sprague-Dawley rats through an incision in the atlantooccipital membrane and the animals were killed at postoperative intervals of 5 and 8 weeks. Reactive changes that could be correlated with the extent of contact with the implant occurred in the periventricular tissue. The ependyma lining the ventricle underwent a progressive loss of cilia and microvilli, became attenuated and, in circumscribed areas, was lost entirely. A significant subependymal gliosis accompanied these changes. In regions denuded of ependyma, neurons and glia were exposed directly to the cerebrospinal fluid. Eruptions of periventricular tissue corresponding precisely to the location of holes in the implanted tubing were observed on both the vermal surface of the cerebellum and the floor of the ventricle. Evaginations from the surface of the inferior vermis and the floor of the ventricle were most prevalent at 5 and greatest at 8 weeks postimplantation, respectively. Gliosis combined with mechanical factors are believed to be responsible for development of these periventricular tissue evaginations, which may be a factor in the pathogenesis of cerebrospinal fluid shunt obstruction in treated human hydrocephalus.     

Radiotherapy planning: direct tumor location on simulation and port films using CT. Part I. Principles

Although there have been great advances in cancer diagnosis in recent years, it remains difficult to transfer tumor location information from cross-sectional computed tomographic (CT) scans or magnetic resonance images to the simulation and verification films used in planning radiotherapy. A newly developed system uses radioopaque markers attached to the patient as reference points. These markers are identified on both CT scans and simulation films and their locations entered into the treatment planning computer. The tumor and any desired normal structures are then outlined manually on each CT section. Transparent overlays produced by the computer show the position of the reference markers and tumor outlines for any combination of gantry angles and source-film distance. Because the overlays are scaled to the simulation films, the reference points enable precise alignment of overlay and film. The tumor outline thus appears on the simulation or verification films exactly as it is "seen" by the therapy beam, making field verification straightforward and accurate, even on oblique films.     

Maintenance of growth in cystic fibrosis despite reduction in pancreatic enzyme supplementation

Twenty one children with cystic fibrosis were advised to decrease their pancreatic enzyme supplement (PES) dose to less than 10,000 units lipase/kg/day. Mean PES dosage was significantly decreased in 15 patients from 18,380 to 8647 units lipase/kg/day. There were no significant changes in energy or fat intake, but there were significant increases in weight SD score, height SD score, and weight/height ratio.     

Comparison of Two Nitroxide Labile Esters for Delivering Electron Paramagnetic Resonance Probes into Mouse Brain

In vivo quantitation of O₂ in brain has been hindered by a lack of suitable imaging modalities. Development of low-frequency electron paramagnetic resonance (EPR) spectrometers that can detect free radicals in animals in real time makes it feasible to image paramagnetic oximetry probes such as nitroxides in brain tissue. We have shown that masking the carboxyl group of 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 1) as an esterase-labile acetoxymethyl ester yields 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 2). Nitroxide 2 can cross the blood-brain barrier and is then hydrolyzed in situ by esterases to regenerate nitroxide 1, which becomes entrapped in brain tissue. Seeking to improve the loading of nitroxides into brain, we synthesized the more lipophilic pentanoyloxymethyl ester, 3-pentanoyloxymethoxycarbonyl-2,2,5,5-tetramethyl-1- pyrrolidinyloxyl (nitroxide 3). We report that the higher lipophilicity of nitroxide 3 does not significantly increase its ability to generate EPR signals in the mouse brain. Therefore, irrespective of whether nitroxide 2 or 3 was injected, similar levels of nitroxide were entrapped in brain tissue. These findings suggest that nitroxides 2 and 3 perform comparably well as proimaging agents for measuring O₂ distribution in brain.