Water-soluble contrast media in radiography of small bowel obstruction. Comparison of ionic and non-ionic contrast media

Fifty patients with possible gastrointestinal obstruction, referred for enteric follow-through examination, were randomized for a double-blind, parallel comparison of the hyperosmolar contrast medium Gastrografin and the low-osmolar Omnipaque. The result was that Omnipaque retained its radiographic density in the small bowel better than Gastrografin. Omnipaque was thus a better alternative than Gastrografin in follow-through examinations of intestinal obstruction. Also, 23 patients out of 28 with small bowel obstruction due to peritoneal adhesions, had spontaneous relief of symptoms during the observation period following contrast medium ingestion with no significant difference between the two media. This indicated that enteric follow-through procedures may have a therapeutic efficacy similar to the treatment of small bowel obstruction using nasogastric suction and gastrointestinal rest. Possible mechanisms for this action of the contrast media are discussed.     

Endothelial PDGF-B retention is required for proper investment of pericytes in the microvessel wall

Several platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) family members display C-terminal protein motifs that confer retention of the secreted factors within the pericellular space. To address the role of PDGF-B retention in vivo, we deleted the retention motif by gene targeting in mice. This resulted in defective investment of pericytes in the microvessel wall and delayed formation of the renal glomerulus mesangium. Long-term effects of lack of PDGF-B retention included severe retinal deterioration, glomerulosclerosis, and proteinuria. We conclude that retention of PDGF-B in microvessels is essential for proper recruitment and organization of pericytes and for renal and retinal function in adult mice.     

Beam optics design of compact gantry for proton therapy

A new proton therapy facility for the treatment of deep-seated tumours is being assembled. The proton beam will be applied to the patient under computer control, using dynamic scanning of a focused proton pencil beam to produce a complete three-dimensional conformation of the dose to the target volume. The beam will be applied to the supine patient using a compact isocentric gantry for protons. By combining the scanning of the beam with the beam optics and by mounting the patient couch eccentrically on the gantry, the diameter of the rotating structure can be reduced to 4 m, which is the smallest diameter designed so far for a proton gantry. The paper describes the project especially from the point of view of the optics of the beam transport system of the gantry, including the beam line used to inject the beam into the gantry.     

Occurrence of housedust mites (Astigmata; Pyroglyphidae) in stables

Occurrence of house-dust mites (Astigmata; Pyroglyphidae) in stables. The house-dust mite Dermatophagoides farinae was found in 5 samples derived from a conventional henhouse with fowls and pigeons and from a test animal hutch with rats, mice and rabbits. 63 samples derived from conventional sheds, pigsties and hutches as well as from conventional henhouses and large-scale poultry farms showed negative results. Besides mites of the family Pyroglyphidae mites of the Tyroglyphidae family and/or mucedine were found, which affect the development of mite populations. House-dust mites should be considered in the etiology of allergic diseases of dog, cat and livestock.     

复合生物陶瓷根管充填糊剂体外抑菌实验

目的测定复合生物陶瓷(compound bioactive ceramic,CBC)根管充填糊剂对感染根管内检出率较高的致病菌的抑菌杀菌作用.方法厌氧菌选用产黑色素普氏菌、放线菌、牙龈卟啉单胞菌、二氧化碳噬纤维菌;需氧菌选用金黄色葡萄球菌、a-溶血性链球菌、大肠杆菌.厌氧菌实验采用试管二倍稀释实验材料,用麦氏标准比浊管法(Mc Far Land)[1]比浊受试菌液浓度,比浊为6×105cfu/ml,测定CBC根充糊剂对受式厌氧菌的最小抑菌浓度(MIC),同时测定最小杀菌浓度(MBC);需氧菌实验受试菌液浓度比浊为1.5×108cfu/ml,采用纸片法,参照TMP/SMZ药物纸片标准[2],通过测量抑菌圈直径大小测定CBC根充糊剂对受试需氧菌的抑菌作用.结果CBC根充糊剂对4种厌氧菌的最小抑菌浓度(MIC)为15.62mg/ml,最小杀菌浓度(MBC)为31.25 mg/ml;对受试需氧菌金黄色葡萄球菌、a-溶血性链球菌、大肠杆菌的抑菌圈直径分别为13mm、12mm、10mm.结论实验用CBC根充糊剂对受试验厌氧细菌具有一定的杀菌抑菌作用,对受试需氧菌金黄色葡萄球菌、a-溶血性链球菌表现为中度敏感,对大肠杆菌表现为耐药.     

壳聚糖口腔复合药膜的研究

目的选择壳聚糖作为膜载体,加入芦荟、表皮生长因子(EGF)等药物制备口腔复合膜,探讨各成分的最佳组配方案及药膜的理化性质.方法①将壳聚糖制成膜;筛选各种药物的组配方案.②测定复合膜的理化性质.结果①复合膜厚约0.5mm,质地均匀,外观为红棕色,黏性较好,遇水2min后呈胶膏状,可牢固黏附于黏膜之上.复合膜每平方厘米含水溶性壳聚糖0.007g、芦荟全叶冻干粉0.051g、EGF40IU、丁卡因0.533mg.25℃,1%的复合膜水旋浮液的pH值为6.8±0.1.复合膜在37℃水中的溶化时间为60～90min.②复合膜具有较好的释放性能,可在2～2.5h内释放出绝大部分药物.结论本实验研究表明水溶性壳聚糖是一种良好的膜载体材料,加入芦荟、EGF等不影响其黏附性;而且其药物释放性能很好,可保证药物的有效释放.     

陶瓷正畸托槽材料的生物安全性初步评价

目的采用细胞毒性试验、口腔黏膜刺激实验对一种陶瓷正畸托槽材料的生物安全性进行初步的评价.方法根据国家标准,应用体外细胞培养琼脂覆盖法对这种陶瓷材料进行细胞毒性评价,利用大耳白兔检测这种陶瓷材料对口腔黏膜的刺激反应.结果这种陶瓷材料的细胞毒性试验评级为0级,口腔黏膜刺激试验中试验动物未见局部及全身的不良刺激反应(包括组织学观察).结论这种陶瓷材料不具有细胞毒性及对口腔黏膜的不良刺激反应.     

Synthetic mimetics of the gp130 binding site for viral interleukin-6 as inhibitors of the vIL-6-gp130 interaction

The transmembrane protein gp130 acts as the signal transducing receptor subunit for interleukin-6 type cytokines, including viral interleukin-6, which is encoded by the Kaposi's sarcoma-associated herpes virus. Viral interleukin-6 has been shown to mimic human IL-6 functions, including activation of the JAK1 and STAT1/3 signaling pathways. Based on the crystal structure of three extracellular domains of gp130 in complex with viral interleukin-6, we have designed and synthesized a range of assembled peptides that mimic the sequentially discontinuous binding site of gp130 for viral interleukin-6. These peptides, which present the three binding site fragments of gp130 in a nonlinear, discontinuous fashion, were shown to inhibit the interaction of gp130 with viral interleukin-6, as well as the stimulation of viral interleukin-6-induced cell proliferation. These results validate the concept of synthetic mimicry of discontinuous protein-binding sites through assembled peptides, and the use of such molecules as modulators of protein-ligand interactions.     

Human impacts and Anthropocene environmental change at Lake Kutubu,a Ramsar wetland in Papua New Guinea

The impacts of human-induced environmental change that characterize the Anthropocene are not felt equally across the globe. In the tropics, the potential for the sudden collapse of ecosystems in response to multiple interacting pressures has been of increasing concern in ecological and conservation research. The tropical ecosystems of Papua New Guinea are areas of diverse rainforest flora and fauna, inhabited by human populations that are equally diverse, both culturally and linguistically. These people and the ecosystems they rely on are being put under increasing pressure from mineral resource extraction, population growth, land clearing, invasive species, and novel pollutants. This study details the last ∼90 y of impacts on ecosystem dynamics in one of the most biologically diverse, yet poorly understood, tropical wetland ecosystems of the region. The lake is listed as a Ramsar wetland of international importance, yet, since initial European contact in the 1930s and the opening of mineral resource extraction facilities in the 1990s, there has been a dramatic increase in deforestation and an influx of people to the area. Using multiproxy paleoenvironmental records from lake sediments, we show how these anthropogenic impacts have transformed Lake Kutubu. The recent collapse of algal communities represents an ecological tipping point that is likely to have ongoing repercussions for this important wetland’s ecosystems. We argue that the incorporation of an adequate historical perspective into models for wetland management and conservation is critical in understanding how to mitigate the impacts of ecological catastrophes such as biodiversity loss.

Wetlands provide a range of benefits to human, animal, and plant life and yet are under increasing threat from industrialization, expanding human populations, and climate change. In 1975, the Ramsar Convention was established to promote the sustainable use of wetlands and halt their decline worldwide (1). One of the commitments that parties to the convention make is to declare as early as possible any changes to the ecological character of Ramsar wetlands as a result of developments, pollution, or other human interference (2). This requires knowledge of the “natural” or “baseline” state of the wetland prior to major human interference (3, 4), as well as ongoing monitoring of the site. In some cases, major alterations to wetlands have occurred prior to Ramsar Convention listing, and so the baseline state is not known. Baseline information can be obtained from a multiproxy analysis of sediment core records that built up prior to the altering event (5). These sediment records can also be used as a cost-effective way to track changes in the ecological health of the site during and after such disturbances (3, 4). Here, we use the case study of Lake Kutubu, a Ramsar site in Papua New Guinea (PNG; Fig. 1), as a demonstration of this approach.Open in a separate windowFig. 1.Sediment cores, resource extraction infrastructure, and settlements at Lake Kutubu, PNG. The green dotted line is the catchment boundary. The shaded areas are 1,000 m contours after Bayly et al. (16). This map was created using ArcGIS software by Esri (http://www.esri.com) and contains information from Humanitarian OpenStreetMap Team Open Street Map (HOTOSM) PNG Waterways (https://data.amerigeoss.org/tl/dataset/hotosm_png_waterways) and PNG roads 2014 (https://png-data.sprep.org/dataset/png-roads/resource/2ea995e6-6483-42db-a71a-ad58f9fbb2de), which is made available under the Open Database License (https://opendatacommons.org/licenses/odbl/1-0/).Paleoenvironmental ecological baselines have been successfully developed to define “limits of acceptable change” for Ramsar wetlands in several countries (e.g., refs. 5, 6). The feasibility, cost-effectiveness, and long-term assessment of these baselines allow for any country, independent of economic status, to assess the impacts of resource extraction, other human activities, and climate change on wetland areas. Baselines have the potential to function as ecological tools for environmental justice and to support local communities in tracking the state of their environment. They can also support the Ramsar Convention by providing evidence for ecological impacts and highlighting areas in need of better management.The Ramsar Convention was adopted in PNG on 16 July 1993, and Lake Kutubu (Ramsar site no. 961) was declared a Ramsar site in 1998 (7), due primarily to its exceptional levels of fish endemism supported by food chains based on unique species of autochthonous primary producers (8). It was determined that significant degradation or loss of the lake would substantially reduce the ecological diversity of the region (8). Yet, at the time of listing, the Lake Kutubu region had already been subject to altered scales of human disturbance with the establishment of European administrative bases in the 1930s (9), low-level development from the 1940s to 1970s, and then the much more significant impacts relating to the establishment of petroleum and natural gas projects from the 1980s (10, 11), followed by large-scale land clearance, construction, and immigration into the area (10, 12, 13). A baseline study of the lake’s condition prior to these disturbances is needed to understand the scale of change and to provide a restoration target (14). Such targets are essential where ongoing development pressures and environmental governance issues can otherwise lead to long-term degradation of environments and livelihoods. We apply a paleoenvironmental multiproxy approach to assess the history of contamination, ecological impacts, and deforestation in sediments of Lake Kutubu. The identification of detrimental impacts in Lake Kutubu is crucial to provide guidance for the implementation of mitigation measures in tropical lakes under similar modern pollution pressures. This approach includes the analysis of fire and pollution indicators, aquatic algae, chlorophyll-a, and geochemistry in the lake sediments from before and after resource extraction activities commenced, providing a detailed profile of chemical and ecological changes. These data are compared to historic records and observations on the state of the lake prior to and since the start of resource extraction in the 1990s.