How self-initiated memorized movements become automatic: a functional MRI study

We used functional magnetic resonance imaging (fMRI) and dual tasks to investigate the physiology of how movements become automatic. Normal subjects were asked to practice some self-initiated, self-paced, memorized sequential finger movements with different complexity until they could perform the tasks automatically. Automaticity was evaluated by having subjects perform a secondary task simultaneously with the sequential movements. Our secondary task was a letter-counting task where subjects were asked to identify the number of times a target letter from the letter sequences was seen. Only the performances that achieved high accuracy in both single and dual tasks were considered automatic. The fMRI results before and after automaticity was achieved were compared. Our data showed that for both conditions, sequential movements activated similar brain regions. No additional activity was observed in the automatic condition. There was less activity in bilateral cerebellum, presupplementary motor area, cingulate cortex, left caudate nucleus, premotor cortex, parietal cortex, and prefrontal cortex during the automatic stage. These findings suggest that most of the motor network participates in executing automatic movements and that it becomes more efficient as movements become more automatic. Our results do not provide evidence for any area to become more activated for automatic movements.     

大鼠丘脑腹后核小细胞部向岛皮质的投射─内脏性传入通路研究之一

本文用ＨＲＰ示踪技术发现丘脑腹后核小细胞部向岛皮质有明确的定位投射，此发现为探索内脏性传入通路提供新的形态学资料．本文还用Ｎｉｓｓｌ法研究了丘脑腹后核小细胞部的细胞构筑，为丘脑腹后核小细胞部的核团划分、形态特征及细胞构筑学积累了资料．     

Cellular characterization of blastocysts derived from rabbit 4-, 8- and 16-cell embryos and isolated blastomeres cultured in vitro

The purpose of this study was to investigate the developmental potential of isolated rabbit blastomeres under various culture conditions to gain insight into their ability to form the two cell lineages of a viable blastocyst. Intact embryos at the 4-cell, 8-cell, 16-cell stages and blastomeres isolated from 4-, 8- and 16-cell rabbit embryos (1/4, 1/8 or 1/16 blastomeres respectively) were cultured in drops of one of three different media, each supplemented with either fetal calf serum (FCS), bovine serum albumin (BSA) or polyvinyl alcohol (PVA). The effects of the extracellular matrix fibronectin (FN) on the development of isolated rabbit blastomeres were also investigated. Supplementation of the medium with FCS yielded a higher (P < 0.05) proportion of blastocysts than BSA or PVA, predominantly from 1/4 blastomeres. No major differences were found between the three basic culture media. In 1/4, 1/8 or 1/16 blastomeres, blastocyst formation rates were greater (P < 0.05) in groups cultured in matrix-free (54.5, 59.6 and 54.6% respectively) than in FN-coated groups (35.4, 46.0 and 26.1% respectively). Only in blastocysts derived from 1/4 blastomeres, were the numbers of inner cell mass (ICM) and total cells of blastocysts higher (P < 0.05) in FN-coated groups than in matrix-free groups (12.7 +/- 1.1 versus 8.5 +/- 0.7 ICM, 73.8 +/- 3. 7 versus 57.8 +/- 3.3 total cells). The percentage of blastocysts derived from single blastomeres with ICM cells decreased with increasing cell stage of the parent embryos in FN-coated (93.6, 78.3 and 44.0%, respectively) as well as matrix-free groups (96.2, 69.3 and 55.2%). In FN-coated groups, after 96 h (1/4) or 72 h (1/8 and 1/16) of culture, approximately 20-30% of blastomeres did not develop into normal blastocysts but formed sheets with 30-50 cells attached to the bottom of the dishes. These results indicate that the development of rabbit blastomeres shares important characteristics with those from mouse and domestic species and may thus aid in developing an efficient culture system for blastomeres, derived from human embryos.     

db-cAMP对转化细胞增殖抑制及其对CaM水平和PKⅡ活性的影响

目的　探讨双丁酰 环核苷酸 (db cAMP)对转化细胞增殖及细胞表型作用的机理。　方法　以流式细胞光度术 (flowcytometry ,FCM)、软琼脂集落形成、放射免疫、Northern印迹和激酶活性分析等方法观察db cAMP对转化的C3H1 0 T1 2 小鼠成纤维细胞增殖、细胞表型、钙调素 (calmodulin ,CaM)表达及蛋白激酶Ⅱ (proteinkinaseⅡ ,PKⅡ )活性的影响。　结果　db cAMP(1mmol L)使C3H1 0 T1 2 转化细胞增殖及软琼脂集落形成能力受到显著抑制 ,转化细胞中CaM的表达及PKⅡ活性明显高于正常细胞 ,经db cAMP处理后也受到明显抑制。　结论　细胞转化及cAMP的诱导分化作用与PKⅡ活性的改变有密切相关性     

Genetic diversity of the outer surface protein C gene of southern Borrelia isolates and its possible epidemiological,clinical, and pathogenetic implications

The ospC genes of 20 southern Borrelia strains were sequenced. The strains consisted of B. burgdorferi sensu stricto, B. andersonii, B. bissettii, one undescribed genospecies, MI-8, and one probably new Borrelia species, TXW-1. A high degree of similarity exists between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Lateral transfers of the ospC gene probably occurred between B. burgdorferi sensu stricto and B. bissettii and between B. bissettii and B. andersonii. Internal gene recombination appears to occur among them. The highest degree of genetic diversity among them was observed in the two variable domains (V1 and V2), semivariable domain (SV), and the species-specific epitopes (between amino acids 28 and 31). Differences in ospC sequences among southern strains reflect diversity at the strain and genospecies levels. MI-8, which was recognized as an undescribed genospecies in our previous reports, remains distinguishable in our current analysis of ospC genes and is distinct from B. burgdorferi sensu stricto. Interestingly, another undescribed southern isolate, TXW-1, was not amplified under various PCR conditions. Compared to European B. burgdorferi sensu stricto strains, American B. burgdorferi sensu stricto strains show greater genetic heterogeneity. Southern B. burgdorferi sensu stricto, B. andersonii, and B. bissettii isolates were intermixed with each other in the phylogenetic trees. In the derived trees in our work, at least one southeastern strain of B. burgdorferi, MI-2, most closely aligns with a so-called invasive cluster that possesses many proven human-invasive strains. Transmission experiments show that MI-2 and the strains in this group of southern spirochetes are able to infect mice and hamsters and that the typical vector of Lyme disease, Ixodes scapularis, can acquire the spirochetes from infected mammals. Currently, strain MI-2 appears to be the only southern isolate among the 20 we analyzed that clusters with an OspC invasive group and thus might be invasive for humans.     

Heat shock proteins generate beta-chemokines which function as innate adjuvants enhancing adaptive immunity

Heat shock proteins (HSP) are widely distributed and highly immunogenic molecules. A novel property reported here is that stimulation with HSP70 of CD8-enriched T cells derived from naive non-human primates caused a dose-dependent increase in concentrations of the beta-chemokines RANTES, macrophage inflammatory protein (MIP)-1alpha or MIP-1beta. However, the concentrations of these beta-chemokines were greatly increased when the CD8 T cells derived from HSP70-immunized non-human primates were stimulated with HSP70. HSP linked to peptides or proteins combined generation of beta-chemokines with an adjuvant function by enhancing specific T cell proliferative responses and IgG and IgA antibodies. The beta-chemokine and adjuvant functions were also elicited by topical mucosal administration of HSP linked to an antigen. We postulate that microbial HSP can stimulate beta-chemokine production which may be responsible for innate adjuvanticity, as was found in cells eluted from normal rectal mucosal tissue, and constitutes a significant component of the mucosal-associated lymphoid system. Furthermore, stimulation of innate immunity may drive adaptive immunity and account for the protective effects of HSP against tumors and viruses.     

Projections from the hypothalamus and its adjacent areas to the posterior pituitary in the rat

Cholera toxin conjugated horseradish peroxidase was injected into the posterior pituitary and its afferents traced in 21 albino rats. The neuronal processes as well as the perikarya were elaborately displayed. The principal and retrochiasmatic supraoptic nuclei and the magnocellular paraventricular subnuclei were densely labelled. The accessory cell groups or nuclei labelled included: the medial preoptic and anterior hypothalamic areas, the anterior and posterior fornical nuclei, the lateral hypothalamic area, the nucleus circularis and nucleus of the forebrain bundle and hitherto unknown or not fully appreciated retrochiasmatic area, the dorsal accessory groups in an area between the stria medullaris and fornix, on the one hand, and the stria terminalis and internal capsule, on the other, and a well developed subependymalperiventricular zone. The medial preoptic nucleus, subfornical organ and organ vasculosum laminae terminalis were also weakly stained. Dendrites of the magnocellular paraventricular nucleus have been said by some to be largely confined to the subnuclei in which they lie. Immunohistochemical studies have proved that they extended beyond their nuclear confinement. The present study has found much wider extension of their dendritic fields. In fact, dendrites of the magnocellular neurosecretory cells in general were long and had a certain degree of directional bias. Several sites projecting to the posterior pituitary were closely related to the cerebrospinal fluid. Namely, the subependymal neuronal plexuses along the third ventricle and beneath the interventricular foramen, and the subpial dendritic plexuses of the supraoptic and retrochiasmatic supraoptic nuclei. Neurons were seen to squeeze in-between the ependymal cells, bringing themselves very close to the cerebrospinal fluid. No direct cerebrospinal fluid-contacting elements, either cell bodies or processes, however, could be ascertained. It is proposed that these plexuses may monitor changes in the cerebrospinal fluid. Besides the principal neurohypophysial tract the posterior pituitary was found in the present study to receive its afferents via two accessory fasciculi, one coursing in the medial forebrain bundle and the other running along the lateral wall of the infundibular recess subependymally.     

Cytologic diagnosis of hepatocellular carcinoma by fine-needle aspiration biopsy

From 1976 to June 1982, 237 patients with clinical suspicion of hepatic malignant disease underwent guided percutaneous fine-needle aspiration biopsy of the liver. Of these, 12 were diagnosed cytologically as "hepatocellular carcinoma" and this diagnosis was confirmed in the follow-up of all cases. On the basis of the cytomorphologic features observed in the aspirates, the tumor was subclassified into three types; well differentiated, pleomorphic large cell; and poorly differentiated. The various cytologic appearances of different types of hepatocellular carcinoma are presented and illustrated. Cytomorphologically, these three types of hepatocellular carcinoma were distinctly different and their cytomorphologic features were also sufficiently distinctive from those of secondary hepatic cancer to be diagnostic. Guided percutaneous fine-needle aspiration biopsy of the liver appears to be a definitive minimally invasive means of establishing the diagnosis of hepatocellular carcinoma, and promises to be a valuable diagnostic procedure for potentially resectable localized hepatocellular carcinoma.     

Assessing the Impact of Salt Reduction Initiatives on the Chronic Disease Burden of Singapore

Globally, many countries are facing an increasing burden of chronic disease due to ageing populations, of which cardiovascular disease forms a large proportion. Excess dietary sodium contributes to cardiovascular disease risk and requires intervention at a population level. This study aimed to quantify the impact of several salt reduction initiatives on population health over a 30-year horizon using GeoDEMOS, a population model from Singapore. Four interventions were modelled in four demographic groups in 2020 for a total of 16 intervention scenarios. The effect of 0.5, 2.0, and 4.0 g/day reductions in daily salt consumption, along with adherence to the World Health Organization guidelines of a maximum of 5.0 g of salt each day, was modelled in the entire population, including the overweight and obese, the elderly, and diabetics. In each scenario, the number of averted incident cases of acute myocardial infarction and stroke, along with the disability-adjusted life years up to 2050, was monitored. We found 4.0 g/day reductions in salt consumption were the most effective when implemented across the entire population, resulting in 24,000 averted incident cases of cardiovascular disease and 215,000 disability-adjusted life years over 30 years. This is a large figure when compared with the 29,200 projected annual incident cases of cardiovascular disease in 2050. When targeted at specific high-risk demographic groups, the largest effects were observed in the overweight and obese, with the same intervention yielding 10,500 averted incident cases of cardiovascular disease and 91,500 disability-adjusted life years. Quantifying the benefits of salt reduction initiatives revealed a significant impact when administered across the entire population or the overweight and obese. Health promotion efforts directed toward sustainably reducing salt consumption will help to lower the chronic disease burden on the healthcare system in years to come.