Cochlear ablation in deafness mutant mice: 2-deoxyglucose analysis suggests no spontaneous activity of cochlear origin

Deafness mutant mice show no stimulus-related cochlear potentials as well as abnormal electrically-evoked responses recorded from the inferior colliculus. Abnormal spontaneous activity in the auditory periphery could result in abnormal development and/or maintenance of the central auditory pathways. We therefore assessed spontaneous activity of cochlear origin in the central nuclei of the mutants by ablating one cochlea and subsequently using the 2-deoxyglucose (2DG) technique to study metabolic activity. Any asymmetries in labeling in a given nucleus should be due to spontaneous activity in the cochlear nerve on the unoperated side. In control animals (+/dn mice undergoing unilateral cochlea ablation), statistically significant decreased 2DG labeling was observed in the ipsilateral PVCN and AVCN, and contralateral MNTB and IC; all receive primary excitatory input from the ablated ear. No significant differences in labeling between right and left sides were observed in any of the nuclei studied in the mutant animals. These findings suggest that there is no spontaneous activity of cochlear origin in these mutants, even though many cochlear nerve fibers and spiral ganglion cells survive.     

319例352眼眼外伤疗效观察

采用综合治疗，抗炎，散瞳，局部治疗与全身应用免疫抑制疗法，治疗３１９例３５２眼外伤获得了满意的疗效，眼球挫伤１０４例，眼球穿孔伤９３例，化学烧伤７１例，眼炸伤４６例。眼热烧伤５例，治疗包括及时清创胶粘或缝合，清除前房出血合理用皮质类固醇和免疫抑制剂等。眼球挫伤治愈率９７．１２％，穿透伤９３．１８％，热烧伤６６．６７％。３１９例眼外伤治愈率９４．６７％好转５．３３％，并对各种治疗方法进行了讨论。     

Computed tomography as a screening exam in patients with suspected blunt aortic injury.

BACKGROUND: Chest computed tomography (CT) screening of patients with blunt trauma for thoracic aortic injury is controversial. This study was undertaken to determine whether CT could exclude aortic injury and be used to select patients for aortography. METHODS: Computed tomography and aortography were used to evaluate 155 patients with blunt trauma. Computed tomography scans were reviewed separately by four attending radiologists who were unaware of the patients' clinical course and angiographic findings. RESULTS: Eight of 155 patients had aortic injuries requiring operation. Computed tomography scans in five patients were read as positive by all reviewers. One scan was read as positive by three reviewers and as negative by one. Two scans were read as positive by two radiologists and as negative by two. After poor scans were excluded, the combined sensitivity of CT for detecting aortic injury was 88%, specificity was 54%, positive predictive value was 9%, and negative predictive value 99%. CONCLUSIONS: The sensitivity of CT scan for indicating the need for aortography is observer dependent. As CT manifestations of aortic injury are often subtle, CT does not reliably exclude aortic injury.     

Lobucavir-induced proliferative changes in mice

Nucleoside analogues are used in the treatment of viral infections, including those caused by human immunodeficiency virus, cytomegalovirus, and herpes virus. These drugs are beneficial in the treatment of human disease, but are associated with toxicities that often limit their intended therapeutic use, including anemia, neutropenia, peripheral neuropathy, and myopathy. Some of these compounds have been reported to be carcinogenic in rodents. To investigate the carcinogenic potential of lobucavir, a nucleoside analogue, three groups of 60 male and female mice were orally administered lobucavir at daily doses of 10, 50, and 250 mg/kg (males) or 30, 150, and 750 mg/kg (females) over a period of 104 weeks. Two identical groups of 60 male and female mice each served as controls. The morphology and the incidence of neoplasms is described and compared with the tumor spectrum of other nucleoside analogues. Light microscopically, lobucavir-induced neoplastic lesions consisted of upper digestive tract squamous cell neoplasia in males and females; cervical, vaginal, and cutaneous squamous cell neoplasia in females; and Hardarian gland adenomas and adenocarcinomas in male mice. These results suggest that long-term administration of lobucavir causes neoplasia in mice, the spectrum of which resembles that observed after long-term administration of zidovudine or ganciclovir.     

Retrorenal colon: implications for percutaneous diskectomy

It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.     

Glucocorticoid effects on rabbit fetal lung maturation in vivo: an ultrastructural morphometric study.

Maternal administration of glucocorticoids is known to stimulate fetal lung maturation. In the present study, we used microscopy and stereology to evaluate the morphological effects of maternal glucocorticoid treatment on rabbit fetal lung tissue. Betamethasone was administered to pregnant rabbits on days 25 and 26 of gestation at a dose of 0.2 mg/kg body weight. The animals were sacrificed on day 27 of gestation. Glucocorticoid treatment significantly increased the presumptive airspace in the fetal lung tissue but did not alter the relative proportion of epithelium, connective tissue, or vasculature in the tissue. In addition, glucocorticoid treatment significantly increased the proportion of type II cells in the prealveolar epithelium, increased the rate of phosphatidylcholine synthesis, and increased the content of the major surfactant-associated protein, SP-A, in the fetal lung tissue. We could detect no effect of betamethasone on lamellar body cross-sectional area, numerical density, or volume density within fetal lung type II cells. Glucocorticoid treatment of the pregnant doe caused a decrease in the volume density of intracellular glycogen and an increase in the volume density of mitochondria in fetal lung type II cells. Betamethasone treatment did not alter the distance between fetal lung epithelial cells and subadjacent connective tissue cells. However, glucocorticoid treatment increased the number of connective tissue foot processes that pierced the epithelial basal lamina. Thus, glucocorticoid treatment of the pregnant doe results in structural changes in the fetal lung tissue, an acceleration of some aspects of type II cell differentiation, and a concomitant increase in epithelial-mesenchymal interactions.