Firing rate and size distribution of the hind limb extensor and flexor motoneuronal units

Axonal spike size of extensor and flexor motoneurones were subjected to statistical analysis. Extensor motoneurones were isolated in decerebrate cats and the flexor motoneurones in spinalized cats. Smallest spikes were due to gamma motoneurones which could be further classified as small, medium and large. Extensor and flexor alpha motoneuronal units were also divided into these three subgroups. Considering the firing pattern and the cell size extensor alpha units were divided into five types: small-tonic, medium-tonic, large-tonic, large-phasic and largest-phasic. Maximum firing rate of extensor alpha units was directly related to the cell size and was distributed between 5-15, 15-20, 25-40 and 35-55 imp/sec for the small-tonic, medium-tonic, large-tonic and large-phasic motoneurones. Stabilized firing rates were distributed between 5-10, 10-15 and 15-20 imp./sec for the small-tonic, medium-tonic and large-tonic motoneurones. Flexor motoneuronal types and their maximum firing rates were as follows: small-tonic (16 imp./sec), medium-tonic (24 imp./sec), small-phasic (37.5 imp/sec), medium-phasic (30 imp./sec), large-phasic (46 imp./sec) and largest-phasic (only one or two impulses). The functional significance of the results was discussed considering the axonal spike size as an index for the cell size.     

基因探针监测巨细胞病毒潜伏感染的母儿间传播

本文采用基因探针检测孕妇静脉血及新生儿脐静脉血白细胞中CMVDNA，同时应用ELISA检测其血清中IgG、IgM．结果：10例孕妇CMV-DNA阳性，占8．7％(10／115)，这10例孕妇血IgG均阳性，IgM均阴性；17例新生儿CMV—DNA阳性．占14．3％(17／119)，其中IgM阳性2例，占1．7％(2／119)。本次研究中配对者79例，母儿CMV—DNA均阳性者8例，新生儿CMV—DNA阳性而母亲阴性者4例。上述CMV-DNA阳性者均无临床症状。研究结果提示基因探针可监测CMV的潜伏感染，从而进一步研究CMV感染的母儿传播机制。     

重组风疹病毒外膜蛋白E1的表达及其在血清学中的初步应用

目的 在大肠埃希菌中表达重组风疹病毒外膜蛋白E1,用其作为包被抗原,建立一种用于诊断风疹病毒感染的ELISA检测方法 .方法 通过基因重组的方式构建表达质粒并在大肠埃希菌中表达风疹病毒外膜蛋白E1,蛋白纯化后作为包被抗原,用ELISA的方法 检测世界卫生组织(WHO)的风疹检测质控血清以及来自广西桂林的未知血清样本.结果 采用WHO用于风疹检测的质控血清对所表达的重组抗原的抗原性进行鉴定,通过试验,特异性、敏感性均为100%.用表达的抗原对来自我国广西的200份未知血清样本进行风疹病毒外膜蛋白抗体的检测,阳性率为93%,与文献报道的我国其他地区风疹病毒抗体阳性率基本一致.结论 通过实验我们表达了具有良好抗原性的风疹病毒外膜蛋白E1,为进一步研究风疹病毒感染的实验室诊断技术奠定了基础.     

A phage-displayed single chain variable fragment that interacts with hepatitis B core antigen: library construction, selection and diagnosis.

BACKGROUND: Phage display is an alternative method for constructing and selecting antibodies with desired specificity towards an antigen. OBJECTIVES: To construct a library of single chain variable fragment (ScFv) towards hepatitis B core antigen (HBcAg). To isolate a ScFv phage clone that interacts with HBcAg and to develop a phage-ELISA for detecting the antigen. STUDY DESIGN: Mice were inoculated with HBcAg and RNA was extracted from their spleen cells. The genes encoding heavy (V(H)) and light (V(L)) chains were amplified, linked via PCR and cloned into a phagemid vector. Phage particles displaying ScFv were panned against HBcAg and a selected clone was characterized and employed as a diagnostic reagent for detecting HBcAg in serum samples. RESULTS: A phage clone that interacts with HBcAg was selected from the antibody library. The binding of the phage to HBcAg was inhibited by a cyclic peptide bearing the WSFFSNI sequence. A phage-ELISA was established using the recombinant phage and as low as 10ng of HBcAg can be detected by the assay. CONCLUSION: The ScFv displayed on the surface of filamentous phage is an alternative choice for diagnosis of HBcAg in serum samples.     

Insertion/deletion mutations of type I oculocutaneous albinism in chinese patients from Taiwan

Type I oculocutaneous albinism (OCA1) is an autosomal recessive disorder, which is caused by the reduction or the absence of tyrosinase activity in melanocytes of the skin, hair and eyes. Although tyrosinase mutations of OCA1 have been extensively analyzed in most populations worldwide, there is no systemic study of OCA1 mutation in Chinese patients. By use of single strand conformation polymorphism and direct sequencing, we had detected 21 mutant alleles out of 24 OCA1 chromosomes screened (87.5%). Detected mutant alleles include one splicing site, three insertion/deletion and five missense mutations, of which the splicing site nucleotide alteration (IVS 1-3C>G) and two each of the insertion/deletion (232-233 ins GGG and 861-862 del TT) and missense mutations (Cys 289 Gly and Trp 400 Leu) are novel. The ins/del mutations accounts for about 37.5% in Chinese OCA1 alleles. The 232-233 ins GGG, one of the novel mutations, was found to be most frequent (25%) among the OCA1 alleles in Chinese. Through this study, we found that while some of the OCA mutant alleles were identified in other populations, ethnic difference still exists. Hum Mutat 14:542, 1999.     

A novel method for isolation of Chlamydia pneumoniae by treatment with trypsin or EDTA.

To establish a novel method for the efficient isolation of Chlamydia pneumoniae, experiments were performed to determine the effects of EDTA or trypsin treatment of C. pneumoniae on its adsorption and inclusion body formation. Treatment of C. pneumoniae with 0.1% trypsin or 1 mM EDTA significantly increased inclusion body-forming activity from 8,000- to 10,000-fold higher than that of the control. C. pneumoniae was successfully isolated in cultured cells which were inoculated with clinical specimens after treatment with 0.1% trypsin.     

^99mTc-DTPA肾动态显像及β2-m水平在评价肾移植受者肾功能中的价值

目的：探讨^99mTc-DTPA肾动态显像半定量参数和血、尿β2-m水平测定对肾移植术后早期并发症诊断与鉴别诊断的价值。方法：28例肾移植病人术后均进行放射性核素^99mTc-DTPA肾动态显像,同时测定移植肾的肾小球滤过率（GFR）、膀胱放射性计数与移植肾放射性计数比值（B/K值）和移植肾放射性1min计数与腹主动脉放射性1min计数比值（K1min/A1min比值）。在进行放射性核素肾动态显像前所有病人均收集其血液和尿液标本,采用放射免疫分析测定血、尿β2-m水平。结果：12例肾功能正常者肾动态显像示肾血流灌注及功能良好,GFR值为（49.1±6.1）ml/min,B/K值均〉3,K1min/A1min比值为8.18±1.41;4例急性排斥反应者肾血流灌注受损程度重于功能相,GFR值为（33.2±5.3）ml/min,B/K值均〈1,K1min/A1min比值为2.59±0.86,β2-m水平以血β2-m升高明显;8例慢性排斥反应者肾血流灌注和功能相均同时受损,GFR值为（19.8±7.5）ml/min,B/K值均〈1,K1min/A1min比值为2.19±0.84,β2-m水平也以血中升高明显;2例肾小管坏死者及2例环孢素A肾中毒者肾血流灌注受损均轻于功能相,GFR值分别为（38.5±4.1）ml/min和（39.4±5.81）ml/min,B/K值均〈1,K1min/A1min比值分别为5.83±0.84和6.01±0.66,β2-m水平以尿中升高显著。结论：放射性核素肾动态显像半定量参数K1min/A1min比值和B/K值,结合肾移植病人术后血、尿β2-m水平联合分析可早期初步鉴别排斥反应的类别,可作为判断移植肾受损程度、原因及预后估测的敏感指标。     

Integrating complementary and alternative medicine instruction into health professions education: organizational and instructional strategies.

A few years ago, the National Institutes of Health National Center for Complementary and Alternative Medicine funded a program called the Complementary and Alternative Medicine (CAM) Education Project. Grantees were 14 medical and nursing schools and the American Medical Student Association, which funded six additional medical schools. Grants were awarded in cohorts of five per year in 2000, 2001, and 2002-2003.The R25 grant recipients identified several major themes as crucial to the success of integrating CAM into health professions curricula. The rationale for integrating CAM curricula was in part to enable future health professionals to provide informed advice as patients dramatically increase the use of CAM. Success of new CAM education programs relied on leadership, including top-down support from institutions' highest administrators. Formal and informal engagement of key faculty and opinion leaders raised awareness, interest, and participation in programs. A range of faculty development efforts increased CAM-teaching capacity. The most effective strategies for integration addressed a key curriculum need and used some form of evidence-based practice framework. Most programs used a combination of instructional delivery strategies, including experiential components and online resources, to address the needs of learners while promoting a high level of ongoing interest in CAM topics. Institutions noted several benefits, including increased faculty development activities, the creation of new programs, and increased cross- and inter-university collaborations. Common challenges included the need for qualified faculty, crowded and changing curricula, a lack of defined best practices in CAM, and post-grant sustainability of programs.     

Association between genetic variants in sortilin-related receptor 1 (SORL1) and Alzheimer's disease in adults with Down syndrome

Recent reports have suggested that variants in the sortilin-related receptor gene (SORL1) increase the risk of late onset Alzheimer's disease (AD) in Northern European, Hispanic, African–American and Isreali–Arab populations. SORL1 directs trafficking of amyloid precursor protein (APP) and under-expression of SORL1 may lead to over-expression of β amyloid peptides. Adults with Down syndrome (DS) over-express APP and have early onset and high risk for AD. We investigated the relation of seven variants in the gene for SORL1 to age at onset and risk for AD among 208 adults with DS, 45–70 years of age at baseline. Participants were ascertained through the New York State developmental disability service system and followed at 18-month intervals. Information from cognitive assessments, caregiver interviews, medical record review and neurological examination was used to establish the diagnosis of dementia. Homozygosity for the minor T allele in rs556349 and for the minor C allele in rs536360 was associated with later age at onset and reduced risk of AD (HR = 0.26, 95% CI: 0.08–0.86; and HR = 0.40, 95% CI: 0.16–0.98, respectively). Mean age at onset was approximately four years later in individuals who were homozygous for those alleles compared with those who had at least one major allele. These findings indicate a modest association of variants in SORL1 with AD. In addition, we did not observe the same alleles to be associated with AD compared with earlier studies, suggesting that these SNPs are in linkage disequilibrium (LD) with the putative functional variants or that expression of the SORL1 gene and hence its interaction with APP might be modified by the extremely high levels of APP characteristic of Down syndrome. Thus, further studies are needed to identify functional variants that influence risk for AD in this uniquely vulnerable population.     

Differential cardiovascular effects of pharmacological agents in chickens selected for high and low body weight.

This study was conducted to investigate whether there are differences in the autonomic nervous system function of chickens from lines selected for high (HWS) or low body weight (LWS). The cardiovascular response to various pharmacological agents was used as an indicator of autonomic nervous system response. Ten individuals from each line and sex were used in the study. Catheters were introduced into the left brachial artery and vein and connected to a MP100-BIOPAC system to record blood pressure and heart rate (HR). Chickens were injected with phenylephrine, atropine, propranolol, and tetraethylammonium chloride (TEAC). The LWS birds exhibited a greater increase in mean arterial blood pressure (MABP) and a lesser increase in HR than the HWS birds following atropine. The response to atropine showed a line and sex interaction in which male birds had a greater increase in HR than females and LWS females had a lower increase in HR than the HWS females. Injection of phenylephrine following pretreatment with atropine caused a baroreceptor reflex in which males showed a greater decrease in HR than females. In response to the beta-adrenergic receptor blocker propranolol, females displayed a greater decrease in MABP than males and LWS birds had a greater decrease in HR than HWS birds. In response to the autonomic ganglionic blocker TEAC, MABP and HR decreased equally in both lines. The percentage of adrenal and sympathetic impact on regulation of HR showed that LWS females required greater adrenal activity than those from the other subclasses. Although changes in HR and MABP ratios in response to phenylephrine were different between lines, these responses were not different when phenylephrine was given following atropine. This pattern of response suggested that HWS birds had greater parasympathetic nervous system activity in order to maintain cardiovascular function. These results demonstrate that selection for HWS or LWS has resulted in greater parasympathetic and sympathetic nervous system tone in birds from the HWS and LWS birds, respectively, and suggest that differences between the lines could be at the level of the chromaffin tissue in the adrenal gland.