Neurons in the rostral cingulate motor area monitor multiple phases of visuomotor behavior with modest parametric selectivity

We examined the cellular activity in the rostral cingulate motor area (CMAr) with respect to multiple behavioral factors that ranged from the retrieval and processing of associative visual signals to the planning and execution of instructed actions. We analyzed the neuronal activity in monkeys while they performed a behavioral task in which 2 visual instruction cues were given successively with an intervening delay. One cue instructed the location of the target to be reached; the other cue instructed which arm was to be used. After a second delay, the monkey received a motor-set cue to be prepared to initiate the motor task in accordance with instructions. Finally, after a GO signal, the monkey reached for the instructed target with the instructed arm. We found that the activity of neurons in the CMAr changed profoundly throughout the behavioral task, which suggested that the CMAr participated in each of the behavioral processing steps. However, the neuronal activity was only modestly selective for the spatial location of the visual signal. We also found that selectivity for the instructional information delivered with the signals (target location and arm use) was modest. Furthermore, during the motor-set and movement periods, few CMAr neurons exhibited selectivity for such motor parameters as the location of the target or the arm to be used. The abundance and robustness of the neuronal activity within the CMAr that reflected each step of the behavioral task and the modest selectivity of the same cells for sensorimotor parameters are strikingly different from the preponderance of selectivity that we have observed in other frontal areas. Based on these results, we propose that the CMAr participates in monitoring individual behavioral events to keep track of the progress of required behavioral tasks. On the other hand, CMAr activity during motor planning may reflect the emergence of a general intention for action.     

大鼠肝抑素纯化及其生物活性的检测

用ＳｅｐｈａｄｅｃＧ－５凝胶过滤层析法，进一步纯化具肝抑素生物活性的大鼠肝蛋白质粗提品，以分离的大鼠再生肝的肝细胞为靶细胞，体外检测各洗脱峰浓缩物对肝细胞增殖的制率结果证明，Ｅ峰浓缩物的抑制作用最强，其活性比为粗提品的２０倍，ＳＤＳ聚丙烯酰胺电泳图及蛋白质迁移率测定表明，该浓缩物的主要成分为分子量１３．５ｋＤ的多肽。本研究对大鼠肝抑素做了初步纯化，验证了该物质在肝再生中起重要调控作用的生物效应。     

Two dinucleotide repeat polymorphisms at the D8S1442 and D8S1443 loci

Two polymorphic dinucleotide (CA) repeat clones were isolated from cosmids, cCI8-1121 and cCI8-1199, mapped to chromosome 8p11.2-p12.     

Platelet interactions with calcium-phosphate-coated surfaces

Many studies have shown that calcium-phosphate (CaP)-coated endosseous implants exhibit more peri-implant bone formation and bone contact at early healing times than uncoated implants. Since the rate of healing is influenced by blood/implant interactions and possibly the degree of blood platelet activation, the aim of this study was to determine whether the topography, microtopography, or the presence of calcium (Ca) and phosphate (PO(4)) ions in the implant surface plays a predominant role in platelet activation. We define the threshold between topography and microtopography as the limit of the scale range of platelets themselves; thus, a microtopographic surface is defined by one which exhibits features 3mum. With the help of four international collaborating laboratories, we prepared 11 titanium and CaP-modified titanium surfaces each with different (micro)topographies and interrogated these surfaces with both platelet adhesion (lactate dehydrogenase activity) and platelet activation (microparticle formation and P-selectin expression) assays. Our results show that: calcium (Ca)- and phosphate (PO(4))-containing surfaces of increasing surface microtopographical complexity exhibit increasing platelet activation; surfaces with similar surface microtopographies show similar levels of platelet activation regardless of the presence of Ca and PO(4) in the surface; and that surface microtopography is responsible for platelet activation rather than the presence of Ca and PO(4) in the surface.     

Conditioned taste aversion using four different means to deliver sucrose to rats

A solution of sucrose either to be drunk from a drinking tube-self-drinking procedure (SD)-or perfused intraorally as a consequence of nose-pokes-self-administration procedure (SA)-or perfused as a consequence of licking an empty tube (LA)-was paired with an LiCl-induced malaise in rats. The effects were compared to those of a procedure consisting of intraoral administration (IO) of sucrose not contingent to any specific action of the rat. Similar levels of conditioned taste aversion (CTA) were obtained but extinction in the IO procedure was quicker than in the SA procedure, which was itself quicker than in the SD procedure. Extinctions in the IO and LA procedures resembled one another and were quicker than in the SD procedure. A step towards deciding between several explanatory hypotheses of these differences was made by conducting two more experiments. The third experiment was based on reinstatement, or not, of the conditioning procedure for the test after standard IO extinction. CTA was produced only when SD was used both at conditioning and test. A fourth experiment was based on latent inhibition where the procedure was changed, or not, between preexposure and conditioning. Latent inhibition was absent only when the rats had been preexposed to sucrose with the SA procedure and conditioned with the SD procedure.     

FINE STRUCTURE OF NEUROBLASTOMA—A CASE REPORT—

Ultrastructural observation was carried out on neuroblastoma cells in a 4-year-old girl. The nuclei of these neoplastic cells were irregular with occasional cytoplasmic invaginations, and proportionally large with diffusely dispersed chromatin substance. Rare mitotic figures were also present. The cell-to-cell interfaces were relatively simple with only finely wavy membranes but without interdigitations. A few desmosomes were, however, apparent. The cytoplasmic pseudopodes were frequently observed in a limited area of the cell surface and nearly free of organelles. The main findings of the intracytoplasmic organelles consisted of some mitochondrial changes, poor development of Golgi bodies, occasional formation of focal cytoplasmic degradation, and intracytoplasmic Abrillar aggregates. Numerous large round to oval dense bodies encircled by a double membrane were highly suggestive of lipid bodies. The central area of rosette-like cell aggregates was noted to be composed of cytoplasmic processes of neoplastic cells.     

Galactosylated chitosan as a synthetic extracellular matrix for hepatocytes attachment

Galactose moiety as the hepatocyte anchorage was covalently coupled with chitosan for the development of synthetic extracellular matrix. Hepatocytes adhesion to galactosylated chitosan (GC)-coated polystyrene (PS) dish became as high as 94.7% after 2 h incubation whereas the hepatocytes adhesion to chitosan-coated PS dish was 69.1%, indication of galactose-specific recognition between GC molecules and asialoglycoprotein receptors of hepatocytes. The DNA synthesis of the hepatocytes adhered to GC-coated dish was increased in the presence of epidermal growth factor (EGF) at low concentration of GC (0.05 microg/ml) whereas the DNA synthesis of the hepatocytes adhered to GC-coated dish was decreased in the presence of EGF at high concentration of GC (5 microg/ml). The spreading shapes of the hepatocytes adhered to the surface in the presence of EGF at low concentration of GC (0.05 microg/ml) were enhanced than in the absence of EGF. The hepatocytes adhered to the surface at high concentration of GC (5 microg/ml) showed round shapes and exhibited many spheroid formation after 24 h in the presence of EGF.     

Galactosylated PVDF membrane promotes hepatocyte attachment and functional maintenance

One of the major challenges in BLAD design is to develop functional substrates suitable for hepatocyte attachment and functional maintenance. In the present study, we designed a poly(vinylidene difluoride) (PVDF) surface coated with galactose-tethered Pluronic polymer. The galactose-derived Pluronic F68 (F68-Gal) was adsorbed on PVDF membrane through hydrophobic-hydrophobic interaction between PVDF and the polypropylene oxide segment in Pluronic. The galactose density on the modified PVDF surface increased with the concentration of the F68-Gal solution, reaching 15.4 nmol galactosyl groups per cm2 when a 1 mg/ml of F68-Gal solution was used. The adsorbed F68-Gal remained relatively stable in culture medium. Rat hepatocytes attachment efficiency on F68-Gal modified PVDF membrane was similar to that on collagen-coated surface. The attached hepatocytes on PVDF/F68-Gal membrane self-assembled into multi-cellular spheroids after 1 day of culture. These attached hepatocytes in spheroids exhibited higher cell functions such as albumin synthesis and P450 1A1 detoxification function compared to unmodified PVDF membrane and collagen-coated surface. These results suggest the potential of this galactose-immobilized PVDF membrane as a suitable substrate for hepatocyte culture.     

太空发育鸡胚的前庭感受器细胞形态学研究

为了探讨太空微重力对鸡胚前庭感觉上皮细胞的形态发育的影响 ,选取在航天飞机 (STS-2 9)发育鸡胚和地面发育鸡胚各两只 ,利用计算机显微测量技术分别测量椭圆囊和球囊的毛细胞、支持细胞核的切面面积、周长、形状系数。太空发育鸡胚的球囊支持细胞核的切面面积、周长显著大于地面组 ,形状系数无差异 ;太空发育鸡胚的椭圆囊支持细胞核的切面面积、周长、形状系数以及椭圆囊和球囊毛细胞的切面面积、周长与地面发育鸡胚相比无明显差异。微重力可能对球囊支持细胞核的体积发育有影响 ,对椭圆囊和球囊的毛细胞以及椭圆囊支持细胞核的形态发育无影响。