Reduction of cataract by plasma etching of intraocular lenses. An animal experiment study

BACKGROUND: We studied if a modification of the silicon intraocular lens (IOL) by plasma etching is able to promote a bonding of the IOL surface and the capsular bag which might inhibit proliferation and migration of lens epithelial cells. METHODS: Silicon-disc lenses (90D, Adatomed), as disposable for regular cataract surgery, were used. Their haptic surface was etched via the use of a SO2 plasma, leaving the optic unmodified. The experiments were done on dwarf rabbits to allow for tight apposition of IOL and bag. Nine rabbits underwent extracapsular lensectomy using propofol anaesthesia and phaco/clear cornea surgical technique. Six eyes each received either no, a regular or a modified IOL. After 11 weeks the eyes were enucleated. Capsular bag and IOL were digitized using a flatbed scanner with transparency adapter. The data obtained were calibrated against a densitometric standard. The densities of the various specimen were analyzed quantitatively using self designed software. RESULTS: In aphacic eyes no significant posterior capsule opacification (PCO) was detectable. In the same time-span the regular IOL had developed a dense, heterogenous PCO. The plasma-treated IOL showed, especially in the central areas, a significant reduction of PCO as compared to untreated IOL. CONCLUSION: The reduction of PCO could not be explained by adhesion of the IOL surface and the capsular bag, which would impair migration of lens epithelial cells and thereby PCO. Likewise, lower PCO may be related to improved hydrophilic properties of the surface-modified IOL.     

Dynamic interstitial laser application for therapy of secondary liver tumors. An animal experiment study

Laser-induced interstitial thermotherapy (LITT) is a promising method of treating different types of tumors. To increase the effectiveness of LITT, a new thermo-controlled application system for minimal invasive intervention was designed. This laser system consists of a laser applicator 3 mm in diameter, insertion equipment and an Nd:YAG laser source. The power of the laser source is controlled dynamically by thermosensors in a water-cooling system of the laser applicator. In in vivo experiments in five pigs, within 10 min we found homogeneous coagulation regions in the liver that were of 3 cm and 5 cm in diameter. Via ultrasound we observed in real time the increasing coagulation zone that appeared as a hyperechogenic halo. However, due to perifocal edema, the real coagulation area was smaller than detected by ultrasound. Macroscopically and microscopically, the coagulation zones showed well-demarcated borders of the coagulation lesions, and the surrounding tissue appeared vital. The reparative reaction after irradiation was early fibrosis. In the course of 4 weeks, the surrounding scar capsule, containing fibrocytes, biliary ductules and collagen fibers enlarged. As a result, the coagulation necrosis became more and more fragmented between collagen fibers and was largely resorbed. The absence of complications in our animal experiments suggest that the technique of thermo-controlled laser light application is safe and useful in therapy for metastases that are not resectable.     

An animal experiment on short gut lengthening

OBJECTIVE: To investigate the anatomical and histological changes of the lengthened gut by a special intraluminal tubular expander on the basis of the theory of "tension-stress". METHODS: Nineteen New Zealand white rabbits were used. A 5 cm segment of the terminal ileum with a pedicle was put underneath the abdominal wall, with its proximal end closed and its distal end exteriorized as a stoma. One week later, as the wound healed well, an expander made of a small rubber tube was inserted into the short gut loop through the stoma. Three milliliters of water was injected as an initial dose. Then 0.5 ml water as an increment was injected subsequently every 12 hours until the total amount of water reached 15 ml and kept stable for two weeks. RESULTS: Anatomically, the length and the capacity of the intestinal loop were recorded, after 15 ml expanding, as an average of 150% lengthening of the original and an average of 293% expansion. Two weeks after the removal of the expander, partial shrinking was observed. A stable lengthening had 123% of the original length, while the capacity reduced to 200% of the original one. Histologically, there was no remarkable changes of the mucosa or submucosa. But significant hypertrophy of the musculature and serosa layer was observed. The total thickness of the musculatures was 618% of the normal control's. Ultrastructurally, there were enlargement of the smooth muscle cells, increase in number and size of the mitochondria in the cytoplasm and widening of the intercellular space. CONCLUSION: A short gut can be lengthened by a tubular expander following the rule of gradual tension and stress.     

Effect of surgical technique on meniscus transplants. A histological, animal experiment study

Heparan sulphate binding to cells of the gastric pathogen Helicobacter pylori at pH 4-6 is common. Binding was inhibited by various unlabelled sulphated polysaccharides and at high ionic strength and pH, but not by carboxylated or non-sulphated compounds. The inhibition by various sulphated compounds such as dextran sulphate and carrageenans was related to the sulphate content and not to the carbohydrate polymer backbone. The IC50 values for heparin and dextran sulphate for H. pylori strain 25 were calculated as 3.55 x 10(-7) M and 5.01 x 10(-6) M respectively. Heparin-binding proteins of H. pylori are exposed on the cell surface, as shown by biotinylation of cell-surface proteins before separation of outer membranes and by an indirect immunofluorescence assay. The strongest biotin-heparin binding by H. pylori was observed with a polypeptide in the 55-60 kDa region.     

Human beta-glucuronidase. I. Recognition and uptake by animal fibroblasts suggests animal models for enzyme replacement studies

As part of an effort to develop an animal model for studies of uptake of human beta-glucuronidase, fibroblasts were established from primary explants of connective tissue from nine different animal species, and examined for their ability to take up human platelet beta-glucuronidase. Endogenous fibroblast beta-glucuronidase was inactivated by heating extracts to 65 degrees for 30 min. Human beta-glucuronidase was stable to this treatment. Uptake of human beta-glucuronidase by animal fibroblasts was measured as heat-stable beta-glucuronidase present in fibroblasts after exposure to partially purified human platelet beta-glucuronidase for 48 hr. Althought all animal fibroblasts examined exhibited some uptake capacity for human beta-glucuronidase, the uptake capacity of different animal fibroblasts varied over a 10-fold range. The uptake capacity of bovine fibroblasts was at least 80% that of human fibroblasts. Rat and hamster fibroblasts showed about half the uptake capacity of human fibroblasts. The rat fibroblasts resembled the human fibroblasts in the kinetics of uptake of hihg uptake (platelet) enzyme, poor uptake of human placental enzyme, and lack of appreciable turnover of enzyme taken up over 4 days. Heating extracts of rat organs containing added human beta-glucuronidase at 65 degrees selectively inactivated rat enzyme.     

An experiment study of the guided bone regeneration

BMP is one of important factors in the pathophysiology of bone regeneration. Fifteen New Zealand rabbits were used in this experiment. We studied the distribution and effectiveness of endogenic BMP on a 10 mm bone defect of radius, by utilizing immunohistochemistry of BMP and quantitative computer imaging system. On the 3rd day, death of osteocytes and BMP positive blood clot were observed. The mesenchymal cells from periosteum and endoosteum, and osteoblast were also BMP positive. By quantitative study, we found there was a gradient distribution of BMP in bone defect, i.e, the value of BMP decreased gradually along the distance from the fracture ends. The maximal value of BMP was noted at the 1st week postoperation. In conclusion, two sources of endogenic BMP were found, one was from the absorption of necrotic tissue of fracture ends, the other was from the secretion of osteogenic mesenchymal cells during the process of bone regeneration. Nonunion of bone defect was caused in part by the gradient distribution of BMP. Accordingly, the concept of effective quantity of endogenic BMP was drawn rosen. It might be a new method in the treatment of bone defect by increasing the concentration of endogenic BMP and improving its distribution.     

Surfactant replacement therapy. An update on applications

Surfactant replacement therapy has been shown to be an effective and often life-saving treatment for newborn infants with respiratory distress syndrome (RDS). This article provides the clinician with an update regarding the various other applications of surfactant replacement therapy, as well as issues related to surfactant administration for the preparations approved for use in pediatric patients.     

隔膜泵两种特殊故障的原因分析与处理

通过隔膜泵两年来在生产运行中出现的两种特殊故障,分析其发生的内在原因,以便从根本上解决隔膜泵在检修方面存在的问题。     

GMB200-2.5型隔膜泵机组设计要点分析

隔膜泵的冲次n和隔膜直径D为影响隔膜泵性能和结构的主要参数。本文主要介绍隔膜泵机组技术参数的合理匹配以及隔膜行程控制系统设计分析。     

动物试验中胆宁片利胆作用研究

胆宁片主要由人工牛黄、水飞蓟素、盐酸小檗碱、延胡索等中药组成,是主治急慢性胆囊炎,胆道感染,胆结石的中成药,具有清热化湿,疏肝利胆的功效.本文通过动物实验进一步阐明本药的利胆作用,为临床应用提供参考依据.     

Comparative psychology and the study of animal learning.

Comparative psychology and the study of animal learning have been closely related since the start of both areas of study. At its inception, comparative psychology addressed questions about the evolution of consciousness and intelligence. The scope of comparative psychology then increased to include a wide range of issues related to behavioral evolution and adaptation. Both of these aspects of comparative psychology are reflected in contemporary research on animal learning. Contemporary investigations of animal learning and cognition reflect the roots of comparative psychology in questions about animal intelligence. Contemporary studies of adaptive specializations and functions of learning are related to the contemporary emphasis in comparative psychology on the role of behavior in evolution and adaptation. In addition, the comparative method remains important in the study of both specialized and general learning processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tracheal replacement with cryopreserved tracheal allograft: experiment in dogs

The purpose of this study was to assess the feasibility of a newly developed field inhomogeneity catheter for interventional MRI in vivo. Different prototypes of a field inhomogeneity catheter (pigtail and multipurpose configuration, balloon catheters) were investigated in pigs. The catheters were introduced in Seldinger technique via the femoral vessels over a guidewire on an interventional MR system (Philips Gyroscan NT combined with a C-arm fluoroscopy unit [Philips BV 212]). Catheters were placed in veins and arteries. The catheter position was controlled by a fast gradient-echo sequence (turbo field echo [TFE]). Catheters were introduced over a guidewire without complications in all cases. Using the field inhomogeneity concept, catheters were easily visualized in the inferior vena cava and the aorta by the fast gradient-echo technique on MR in all cases. Although aortic branches were successful cannulated, the catheters were not well displayed by the TFE technique due to the complex and tortuous anatomy. All animals survived the experiments without complications. MR-guided visualization of a field inhomogeneity catheter is a simple concept that can be realized on each MR scanner and may allow intravascular MR-guided interventions in future.     

An animal model for the behavioral effects of interferon.

Interferon, which is produced during viral infections, has cognitive and neurological effects in humans. A dose of 1600 U/g of mouse interferon-alpha significantly depressed horizontal activity, head pokes into a food chamber, and food intake in mice 10 hr and 24 hr after injection. An 800 U/g dose had only slight effects on horizontal activity and food intake, whereas a 400 U/g dose had no effect. There was no evidence of sensitization to interferon when a second 400 U/g dose was given after the 1600 U/g dose. The results imply that mouse interferon-alpha can be used in mice as a model for studying the fatigue and anorexia produced by interferon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some determinants of unethical decision behavior: An experiment.

Evaluated ethical decision making under different contingencies of reinforcement. A laboratory experiment was devised around a simulated task involving marketing decision making and the possibility of kickback payments to purchasing agents. Ss were 120 graduate business students who made a series of decisions of whether to pay kickbacks or not. When Ss were rewarded for unethical behavior, then unethical behavior was higher than when Ss were not rewarded. Unethical behavior was also higher under increased competition. Four personality variables (locus of control, economic and political value orientation, and Machiavellianism, as assessed by Rotter's Internal–External Locus of Control Scale, the Allport-Vernon-Lindzey Study of Values, and the Mach V Scale) were found to be significant covariates of unethical behavior. Foreign Ss were found to be more unethical than US Ss, but sex was not related to ethical behavior. Overall, results suggest that unethical decision making is a combination of personality, cultural and value orientation, and environmental rewards and punishments. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An experiment of Gestalt group therapy with hospitalized schizophrenics.

Tested the hypothesis that the use of gestalt methods in groups with schizophrenics will increase the level of reality differentiation and perception. 17 21–43 yr old schizophrenics served as Ss. Two measurements of the Rorschach were used to test reality perception. Results show a significant increase in one measurement of reality perception in the experimental group as opposed to the control group, supporting the hypothesis. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dysbaric osteonecrosis in divers and caisson workers. An animal model

Dysbaric osteonecrosis was induced successfully in adult sheep after 12 to 13, 24-hour exposures to compressed air (2.6-2.9 atmospheres absolute) during a 2-month period. All exposed sheep had decompression sickness and extensive bone and marrow necrosis in their long bones. Radiographic analysis of these progressive lesions showed mottled to distinct medullary opacities and endosteal thickening characteristic of dysbaric osteonecrosis. Six months after the last hyperbaric exposure, neovascularization of once ischemic fatty marrow was centripetal from the diaphyseal cortex. Proliferating endosteal new bone, fatty marrow calcification, and appositional new bone formation were widespread. Juxtaarticular osteonecrosis involved marrow fibrosis and loss of osteocytes in subchondral cortical bone. Tidemark reduplication in juxtaarticular bone and cartilage thinning suggested possible early osteoarthritis induction by recurrent episodes of transient ischemia after multiple hyperbaric exposures. Dysbaric osteonecrosis appears to involve a bone compartment syndrome of elevated intramedullary pressure initiated by decompression induced N2 bubble formation in the fatty marrow of the long bones. An animal model that can be used to investigate the pathogenesis, diagnosis, and treatment of dysbaric osteonecrosis is discussed.     

Cipher versus cue reading: An experiment in decoding acquisition.

Phonetic-cue reading involves reading words by storing and retrieving associations between some of the letters in spellings and sounds in pronunciations. Cipher reading involves processing all of the letter–sound relations in spellings. These two types of reading were compared experimentally. Novice beginning readers in kindergarten were assigned either to a group that was taught to decode—the cipher readers—or to a group that practiced isolated letter–sound relations—–the phonetic-cue readers. On posttests, cipher readers learned to read 15 similarly spelled words almost perfectly, whereas cue readers learned less than half of the words. Cipher readers also spelled better than cue readers. Errors indicated that cue readers were processing partial letter-sound cues in words. Results indicated that phonetic-cue reading is another way besides visual memory and decoding to read words. Results documented the importance of beginning readers' advancing beyond cue reading to cipher reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)