Regional differences in the pineal gland of the cotton rat, Sigmodon hispidus: Light microscopic, electron microscopic, and immunohistochemical observations

Abstract: Light microscopic, electron microscopic and immunohistochemical observations of the various portions of the pineal gland of the cotton rat ( Sigmodon hispidus ) were made. The volume of the proximal half occupied about 30% of the whole organ, and pinealocytes were slightly smaller in size in the proximal portion than elsewhere. The distal and intermediate portions contained few interstitial cells and numerous astrocytes, but the proximal portion lacked interstitial cells and had more abundant astrocytes than elsewhere. Astrocytes, which were immunoreactive for glial fibrillary acidic protein, mainly lined the pericapillary spaces in the distal and intermediate portions, but in the proximal portion these cells often surrounded isolated or groups of pinealocytes. In the distal and intermediate portions, abundant sympathetic fibers and less numerous non-sympathetic, peptidergic fibers were mainly localized in the pericapillary spaces; these fibers were sparsely distributed in the parenchyma close to interstitial cells or astrocytes. In the proximal portion, non-sympathetic fibers were scarce and sympathetic fibers were distributed abundantly and almost exclusively in the parenchyma. Most of the sympathetic fibers were adjacent to astrocytes and, occasionally, made specialized contact with them. Fenestrae in the capillary endothelium were numerous in the distal portion but absent in the proximal portion. Thus, marked differences in structure existed between the distal and proximal portions of the pineal gland of the cotton rat, suggesting that both portions are functionally dissimilar. In addition, the present study indicates that the proximal portion of the cotton rat was well developed and showed morphological features similar to the deeply situated pineal glands of other mammals.     

Comparison of lung histopathology and bronchoalveolar lavage cytology in mice and cotton rats infected with respiratory syncytial virus

Lung histology as well as cell number and size distribution in bronchoalveolar lavage (BAL) were compared in Balb/c mice and in cotton rats, of various immune status regarding the respiratory syncytial virus (RSV), when subjected to challenge with RSV. In mock-immunized animals, RSV infection typically caused microscopic inflammatory lesions of the lungs and the presence of inflammatory cells in the BAL. Immunization with a formalin inactivated vaccine prior to challenge increased the severity of the lung lesions and the number of cells recovered in the BAL. We observed that cotton rats are more convenient to study primary RSV infections, inasmuch naive subjects show more pronounced lesions than do naive mice. Conversely, the changes in lung histopathology and in BAL cytology associated with exposure to formalin inactivated vaccine prior to challenge were more apparent in mice, making them a more suitable model for potentiation studies. Moreover, mice showed less individual fluctuations than cotton rats. The reading of the lung sections could be made less tedious by use of computer image analysis, which results paralleled those of conventional examination. In mice, cytological analysis of the BAL could be used in place of lung histology for some potentiation studies since the number of cells recovered in BAL reflected the intensity of the lung lesions and size distribution profiles typical of potentiation were recognized.     

Occupation and pancreatic cancer risk in Louisiana

To study the relation of occupational exposures and pancreatic cancer, we evaluated data from males (198 cases and 209 controls) participating in a hospital-based case-control study conducted in a high-risk area of Louisiana between 1979 and 1983. The questionnaire obtained information on lifetime occupational history, as well as dietary, smoking, and drinking habits and demographic characteristics. After adjustment for smoking and dietary patterns, white collar occupations showed consistent elevations in risk, whereas associations for other occupations were in general unremarkable. Although not significantly elevated, risks for truck drivers (OR = 1.7) and those with long-term employment in machine repair or as mechanics were suggestive (OR = 2.5). No association was found for jobs in oil refining or oil and gas extraction (ORs were 0.5 and 0.4, respectively), although risks were slightly elevated for long-term workers in the chemical processing industry (OR = 1.2). While these associations deserve further study, our findings are consistent with results of other studies which do not suggest that occupational exposures are important determinants of pancreatic cancer.     

Respiratory and nonrespiratory morbidity in a titanium oxide paint factory in Nigeria

A study of 67 subjects in a small titanium oxide paint factory in Nigeria showed 50-54% frequency for airway symptoms, 20-40% for neurological symptoms, and 10-27% for other symptoms. The symptoms were well correlated with exposure (p less than .05) and pulmonary function tests (PFTs). The directly exposed subjects had likelihood odds ratios of 5 to 17 of presenting symptoms compared to controls. The PFT deficit, relative to the expected value, was significantly higher for those with airway symptoms than for those of other symptom categories (p less than .005). There were 28 (42%) cases of restrictive lung impairment. Exposure to cotton dust had confounding influence on the PFT of subjects previously exposed. Smoking rate was very low. These findings indicate the need for worker protection in a manufacturing plant in Nigeria.     

体外产气法对苏丹草与棉秆间组合效应的研究

为了探讨苏丹草(Sudan Grass,SG)与棉秆(Cotton Straw,CS)在瘤胃发酵中的组合效应,本研究将苏丹草与棉秆以100∶0、75∶25、50∶50、25∶75、0∶100比例进行组合,每个组合3个重复,利用瘤胃液体外发酵技术,分析GP(产气量)、pH值、瘤胃液NH3-N(氨态氮)和VFA(挥发性脂肪酸)含量,评价产气量组合效应以及综合组合效应。结果表明:(1)苏丹草和棉秆比例为50∶50和25∶75时,产气量与产气速率较高。(2)24~72h阶段50∶50和25∶75组的组合效应均为正值,且25∶75组的组合效应值最高。(3)苏丹草与棉秆不同比例的组合中,25∶75的组合产生的组合效应最高。     

Medical and industrial hygiene characterization of the cotton waste utilization industry

We studied 260 workers in the cotton waste utilization industry and 310 "blue-collar" control workers from nondusty industries in the same geographic area of the United States by respiratory symptom questionnaire and by pre- and postshift spirometry. We excluded 75 cotton workers and 75 control workers from statistical analysis because of prior hazardous occupational exposures. Plant-wide, 8-hour time-weighted average exposures ranged from 0.28 mg/m3 to 7.80 mg/m3. The overall prevalence of symptoms compatible with byssinosis was 5.9% in cotton workers and 4.7% in the controls. Cotton workers with less than 2 years of employment had a significantly greater prevalence of bronchitis than their control counterparts. The cotton workers with 2 years or more of employment had significantly greater prevalences of bronchitis, shift decrement in forced expiratory volume in 1 second (FEV1) of greater than or equal to 10%, and FEV1/FEV1-predicted less than 80%, than their control counterparts. Regression analysis showed that for matched cotton and control workers, the percentage decrement in FEV1 over the shift was significantly greater for cotton workers; and that in all cotton workers, longevity in industry had a negative effect on the before-shift forced vital capacity (FVC). This study suggests that there are both acute and chronic effects of cotton exposure in the cotton waste utilization industry.     

术后轻度低体温患者组合保暖与充气式加温仪复温效果比较

目的 探讨组合保暖与充气式加温仪在术后轻度低体温患者中的应用效果。 方法 将90例术后轻度低体温患者随机分成两组各45例。观察组使用反光毯和棉被的组合保暖方式复温,对照组使用充气式加温仪复温。 结果 复温后两组的升温值差异未达非劣效边界。两组体感舒适度、寒战和心血管不良事件发生率无统计学差异（均P＞0.05）。 结论 组合保暖方式应用于轻度低体温患者的升温效率与充气式加温仪相当;体感舒适度和安全性与充气式加温仪也相似,适用于此类患者的术后复温。     

脑棉片的简易核对法

脑外科手术时，最令护理人员头痛的是脑棉片的核对。为此，我们将无水塑纸用作核对脑棉片的材料，经临床实践证明，此方法缩短了核对脑棉片的时问，提高了护理人员的工作效率，效果良好。     

Cotton Rats and House Sparrows as Hosts for North and South American Strains of Eastern Equine Encephalitis Virus

Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) is an arbovirus that causes severe disease in humans in North America and in equids throughout the Americas. The enzootic transmission cycle of EEEV in North America involves passerine birds and the ornithophilic mosquito vector, Culiseta melanura, in freshwater swamp habitats. However, the ecology of EEEV in South America is not well understood. Culex (Melanoconion) spp. mosquitoes are considered the principal vectors in Central and South America; however, a primary vertebrate host for EEEV in South America has not yet been identified. Therefore, to further assess the reservoir host potential of wild rodents and wild birds, we compared the infection dynamics of North American and South American EEEV in cotton rats (Sigmodon hispidus) and house sparrows (Passer domesticus). Our findings suggested that each species has the potential to serve as amplification hosts for North and South America EEEVs.     

Mechanism of pajama material on stratum corneum water content under mild cold conditions: explored by hierarchical linear regression

OBJECTIVE: The aim of this study was to explore the effect of fabric material worn during nocturnal sleep on stratum corneum water content (SCWC) under mild cold conditions. METHOD: A controlled cross-over study has been designed to investigate systematically the effects of two kinds of pajama materials, cotton and polyester, on SCWC. Factors such as pajama fabric material, subjective perception and sleep quality were examined. Hierarchical linear regression was applied to assess the association between the factors and SCWC. RESULTS: Fabric material and subjective perception of coldness significantly predicted SCWC in the wear trial. Polyester fabric had a negative effect on SCWC compared with cotton, and subjective perception of coldness also had a negative effect on SCWC. CONCLUSION: The mechanisms by which pajama fabrics affect the SCWC could be due to the different thermal/hygroscopicity properties of the polyester and cotton fabric and the integral involvement of physiological and neurophysiological processes.