经胸右心室穿刺法测量大鼠右心室压力的研究

目的:探索一种技术简单、操作方便、重复性好、容易掌握的大鼠右心室压力测量方法。方法:取健康Sprague Dawley大鼠20只,随机分为实验组(n=10),对照组(n=10)。实验组使用一次性静脉输液针(0.45×13.5 mm)经胸直接穿刺右心室测量右心室压力,对照组使用右心导管,经颈外静脉沿右心房插入右心室测量右心室压力。比较两者操作时间、成功率、右心室压力等指标。结果:实验组从麻醉开始到成功测出右心室压力的时间5.10±1.32 min,对照组为25.21±10.30 min(P0.05)。两种方法所检测到的右心室收缩压、右心室舒张压、右心室平均压无统计学差异(P0.05)。实验组大鼠成功率100%,对照组60%(P0.05)。结论:经胸右心室穿刺法能准确、快速穿刺到右心室并能准确测量右心室压力。     

Air pressure effects on biomass yield of two different Kluyveromyces strains

The use of air pressure as a way of improving oxygen transfer in aerobic bioreactors was investigated. To compare the air pressure effects with traditional air bubbled cultures, experiments using a pressure reactor and a stirred flask, with the same oxygen transfer rate, were made. Kluyveromyces marxianus is an important industrial yeast and some of it show a “Kluyver effect” for lactose: even under oxygen limited growth conditions, certain disaccharides that support aerobic, respiratory growth, are not fermented. This study deals with the effect of increased pressure on the physiological behavior of two Kluyveromyces strains: K. marxianus ATCC10022 is a lactose-fermenting strain, whereas K. marxianus CBS 7894 has a Kluyver-effect for lactose. For K. marxianus ATCC10022 an air pressure increase of 2 bar led to a 3-fold increase in biomass yield. When air pressure increased an enhancement of ethanol oxidation of cell yeasts was also observed. Batch cultures of K. marxianus CBS 7894 exhibited different growth behaviour. Its metabolism was always oxidative and ethanol was never produced. With the increase in air pressure, it was possible to increase the productivity in biomass of K. marxianus CBS 7894. As a response to high oxygen concentrations, due to the increase in oxygen partial pressure, oxidative stress in the cells was also studied. Antioxidant defences, such as superoxide dismutase, catalase, and glutathione reductase, were at high activity levels, suggesting that these yeast strains could tolerate the increased pressures applied.     

Mitogen-activated protein kinases (p38 and c-Jun NH2-terminal kinase) are differentially regulated during cardiac volume and pressure overload hypertrophy

Chronic pressure overload (PO) and volume overload (VO) result in morphologically and functionally distinct forms of myocardial hypertrophy. However, the molecular mechanism initiating these two types of hypertrophy is not yet understood. Data obtained from different cell types have indicated that the mitogen-activated protein kinases (MAPKs) comprising c-Jun NH₂-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 play an important role in transmitting signals of stress stimuli to elicit the cellular response. We tested the hypothesis that early induction of MAPKs differs in two types of overload on the heart and associates with distinct expression of hypertrophic marker genes, namely ANF, α-myosin heavy chain (α-MHC), and β-MHC. In rats, VO was induced by aortocaval shunt and PO by constriction of the abdominal aorta. The PO animals were further divided into two groups depending on the severity of the constriction, mild (MPO) and severe pressure overload (SPO), having 35 and 85% aortic constriction, respectively. Early changes in MAPK activity (2–120 min and 1 to 2 d) were analyzed by the in vitro kinase assay using kinase-specific antibodies for p38, JNK, and ERK2. The change in expression of hypertrophy marker genes was examined by Northern blot analysis. In VO hypertrophy, the activity of p38 was markedly increased (10-fold), without changing the activity of ERK and JNK. However, during PO hypertrophy, the activity of JNK was significantly increased (two-to sixfold) and depended on the severity of the load. The activity of p38 was not changed in MPO hypertrophy, whereas it was slightly elevated (50%) in hearts with SPO. Similarly, ERK activity was not changed in hearts with MPO, but a transient rise in activity was observed in hearts with SPO. The expression of ANF and β-MHC genes was elevated in both PO and VO hypertrophy; however, this change was much greater in hearts subjected to PO than VO hypertrophy. α-MHC expression was downregulated in PO but remained unchanged in VO hypertrophy hearts. Thus, these results demonstrate differential activation of MAPKs in two types of cardiac hypertrophy and this, in part, may contribute to differential expression of cardiac muscle gene expression, giving rise to unique cardiac phenotype associated with different hemodynamic overloads.     

Pressure effects on<Emphasis Type="Italic"> Clostridium</Emphasis> strains isolated from a cold deep-sea environment

Three Clostridium strains were isolated from deep-sea sediments collected at a depth of 6.3–7.3 km in the Japan Trench. Physiological characterization and 16S rDNA analysis revealed that the three isolates were all closely related to Clostridium bifermentans. The spores of all three isolates were resistant to inactivation at high pressure and low temperature. However, despite the fact that the vegetative cells were halotolerant and eurythermal they did not appear to be adapted for growth or viability under the conditions prevailing in the deep-sea sediments from which they were obtained. The results suggest that the isolates had survived as spores in the deep-sea sediments and that the marine benthos could be a source of clostridia originating in other environments.Communicated by K. Horikoshi     

Variation in Spore Polypeptides from Four Species of Vairimorpha

Spore polypeptides from four species of Vairimorpha were separated with sodium dodecyl sulfate polyacrylamide gel electrophoresis for identification and classification. The spore profile for each Vairimorpha species is unique and reproducible. The unweighed pair-group method with arithmethic means is used to construct a phenogram to summarize the relationship of the Vairimorphe species.     

A new method to quantify liner deformation within a prosthetic socket for below knee amputees

Many amputees who wear a leg prosthesis develop significant skin wounds on their residual limb. The exact cause of these wounds is unclear as little work has studied the interface between the prosthetic device and user. Our research objective was to develop a quantitative method for assessing displacement patterns of the gel liner during walking for patients with transtibial amputation. Using a reflective marker system and a custom clear socket, evaluations were conducted with a clear transparent test socket mounted over a plaster limb model and a deformable limb model. Distances between markers placed on the limb were measured with a digital caliper and then compared with data from the motion capture system. Additionally, the rigid plaster set-up was moved in the capture volume to simulate walking and evaluate if inter-marker distances changed in comparison to static data. Dynamic displacement trials were then collected to measure changes in inter-marker distance due to vertical elongation of the gel liner. Static and dynamic inter-marker distances within day and across days confirmed the ability to accurately capture displacements using this new approach. These results encourage this novel method to be applied to a sample of amputee patients during walking to assess displacements and the distribution of the liner deformation within the socket. The ability to capture changes in deformation of the gel liner will provide new data that will enable clinicians and researchers to improve design and fit of the prosthesis so the incidence of pressure ulcers can be reduced.     

An approach to intercalibrate ecological classification tools using fish in transitional water of the North East Atlantic

A simple procedure to harmonise and intercalibrate eight national methods classifying the ecological status using fish in transitional waters of the North East Atlantic is described. These methods were initially intercalibrated and a new method recently developed was added to this exercise. A common human pressure index pre-classified the status of each water body in an independent way. Ecological class boundaries values were established according to the level of anthropogenic pressure using regression analyses. A simulated dataset was used to assess the level of agreement between the fish classification methods. Fleiss’ multi-rater kappa analysis indicated that boundary harmonisation was achieved; all classifications fell within one class of each other and class agreement between methods exceeded 70%. The use of a pressure index to establish boundary thresholds provides a practical method of defining and harmonizing the quality classes associated with human pressures, as required by the European Water Framework Directive.     

Performance and welfare of rabbit does in various caging systems

The objective of the study was to compare production and welfare of rabbit does and their kits housed in various types of cages. Female rabbits were randomly allocated to four groups with the following cage types: CN: common wire-mesh flat-deck cage, without footrest; CF: cage similar to the CN but with plastic footrest; ECWP: enlarged cage with wire-mesh platform; and ECPP: extra enlarged cage with plastic-mesh platform. All does were inseminated on the same day, 11 days after kindlings. Reproductive performance was evaluated during the first five consecutive kindlings. Severity of sore hocks was scored at each insemination. Location preference of the does and the platform usage of their kits were evaluated. Kindling rate, litter size (total born, born alive, alive at 21 and 35 days) and kit mortality were not significantly influenced by the cage types. The litter weight at 21 days was higher in ECWP and ECPP cages than in the CF group (3516, 3576 and 3291 g, respectively; P<0.001), and at 35 days the difference was only significant between the groups ECPP and CF (8712 and 8060 g, respectively, P<0.05). At 21 and 35 days of age, the kits were heavier in large (ECWP and ECPP) than in conventional cages (CF and CN) (P<0.001). At the fifth insemination, the percentage of rabbits with sore hocks’ score of 1 to 2 (0=intact foot pads; 1=no hairs, callus formed, <2.5 cm; 2=no hairs, callus formed, >2.5 cm) and 3 to 4 (3=callus opened, cracks present; 4=wounds) were 58%, 60%, 78% and 48%, and 0%, 5%, 0% and 48% in groups ECPP, ECWP, CF and CN, respectively. Higher number of daily nest visits was observed for CF does than for ECWP does (12.5 v. 5.9; P<0.05). The frequency of multiple nursing events (>2/day) was higher in the CF group than in the ECWP group (12.1 v. 3.2%; P<0.01). Within large cages, the does were observed on the platform more frequently in the ECPP cages compared with the ECWP cages (56.9% v. 31.7%; P<0.001). Similarly, 2.7% and 0.2% of kits at 21 days of age, and 33.2% and 5.2% of kits at 28 days of age, were found on the platforms of ECPP and ECWP cages, respectively. In conclusion, cages larger than the conventional ones improved kits’ weaning weight, plastic footrests and plastic-mesh platforms in conventional and/or large cages reduced sore hocks’ problems, plastic-mesh platforms were more used by both does and kits compared with the wire-mesh platforms.     

周期性静水压对人软骨细胞活性的时间依赖性影响

目的：目前软骨细胞体外研究多为动物模型,本研究以正常成人软骨细胞研究对象,探讨在适当强度、类型的周期性静水压下不同持续时间对软骨细胞活性的影响,探究人软骨细胞体外培养、构建组织工程软骨合适的时间参数。方法：将体外培养的正常成人膝关节软骨第3代软骨细胞随机分为4组：4h组、8h组、12h组、对照组。应用高压恒温静水压加压系统,充入含有95％的空气和5％的CO2混合气体,以2MPa压力大小对3个实验组进行周期性加压,分别每天加压4h、8h、12h,三组加压时间均为10d。10d后倒置相差显微镜下观察4组细胞形态,甲苯胺蓝及II型胶原免疫细胞化学染色进行细胞鉴定,并对II型胶原免疫细胞化学染色行半定量分析。MTT法分析各组软骨细胞增殖情况,流式细胞术检测细胞凋亡率。结果：3个实验组细胞增殖均快于对照组（P〈0．05）,与对照组相比4h组、8h组均抑制凋亡,12h组促进凋亡。12h组第6代细胞开始细胞形态即逐渐发生改变。结论：软骨细胞的增殖和凋亡水平对静水压的作用时间具有依赖性。在2MPa静水压力下,8h组更适合细胞生长,细胞活性更强。为进一步构建组织工程软骨人类模型及组织工程软骨的临床应用提供了一定的实验基础。