Estimating neuron dendritic length in 3D from total vertical projections and from vertical slices

The recently developed method of total vertical projections is illustrated to estimate the total dendritic length of a human Substantia Nigra neuron. Next, the length of the different orders of dendritic branches, and the mean segment length for each order - commonly regarded as important parameters in neuron physiology - are also estimated. Finally, it is shown how to estimate the mean dendritic length in a population of neurons from vertical slices of arbitrary and unknown thickness. Being unbiased and highly efficient, the proposed methods offer interesting alternatives to current procedures used for the metric analysis of neuron arborizations.     

Monitoring of skin response to sodium lauryl sulphate: clinical scores versus bioengineering methods

The present trial was designed to evaluate clinical scores (single observer) of sodium lauryl sulphate (SLS)-induced skin irritation in a group of subjects (n = 10) over a 10-day period along with various skin function parameters. In order to avoid significant variations due to secondary phenomena, the following parameters were recorded with non-invasive instruments in this order: skin capacitance (C1; arbitrary units; CM420 Corneometer), transepidermal water loss (TEWL; g/m2.h; Evaporimeter) and laser Doppler flowmetry (CBFV: cutaneous blood flow values; Periflux). All examinations were performed during winter on reclined relaxed subjects present for at least 10 min in a test room with controlled temperature and relative humidity (t degrees: 19.5-20.7 degrees C and RH: 47.3-60.3%). The analysis of differential data (delta = value at tx-value before test; 2-way ANOVA) was made on single parameters as a function of site (volar forearm versus neck) and time (from 24 h after 48-h occlusion with 5% SLS up to 10 days later). The profile of erythema scores over time differed between neck and forearm, but the delta CBFV readings with the laser Doppler instrument did not detect significant site-time interactions. Roughness (blind evaluation with palpating finger) and capacitance readings (delta C1) showed significant differences between sites, but the profile over time was similar in both locations. delta TEWL did not differ according to anatomical location. The reason for different erythema scores on neck and forearm might be related to inherent regional variation of optical properties of the skin or to a substantial contribution of SLS-induced roughness to the readings of erythema.(ABSTRACT TRUNCATED AT 250 WORDS)     

高原老年人和红细胞增多症病人返回平原后记忆功能的“脱适应”研究

15例离退休健康男性老人和9例红细胞增多症男性病人返回平原后,记忆功能改变的特点:①两组受试者除5例成绩下降外,苏州记忆成绩高于西宁成绩(p<0.01)。②记忆成绩降低现象存在于20%左右的人中。③高原缺氧和返平原脱适应均主要影响短时记忆。     

Sulphanilic acid: divergent results in the guinea pig maximization test and the local lymph node assay

The guinea pig maximization test (GPMT) has proven to be a valuable tool for the identification of the skin sensitization potential of chemicals. The method identifies a hazard which can lead in the EC to compulsory labelling of that chemical. In the present study, data on sulphanilic acid derived from the GPMT has been compared with results from a second guinea pig assay (the cumulative contact enhancement test) and the murine local lymph node assay, both of which require only topical application of chemical. Except for the GPMT, no test identified any sensitizing activity associated with exposure to sulphanilic acid. These latter results are consistent with the experience gained from substantial human exposure in an occupational setting and from which no cases of allergic contact dermatitis to sulphanilic acid have arisen over a 20-year period. In consequence, it is questioned which test protocol in practice has given the more accurate identification of sensitization hazard relevant to man.     

The pitfalls of the dexamethasone suppression test: A biological marker of endogenous depression?

In the past few years there have been numerous publications which have stressed the value of the dexamethasone suppression test (DST) as a diagnostic marker of endogenous depression. Our own studies in 333 psychiatric inpatients and 121 healthy subjects did not reveal a differential diagnostic use for the DST. This result is in good agreement with other results in the literature. Our data demonstrate that intervening variables such as severity of illness, weight loss, sleep disturbances, situational stress, drug and alcohol withdrawal, and the pharmacokinetics of dexamethasone have an important influence on DST results, regardless of the diagnostic classification.     

聚合酶链反应和噬菌体裂解试验监测鼠疫菌的应用比较研究

应用聚合酶链反应 (PL-PCR)技术和噬菌体裂解试验同时对 80株鼠疫菌 ,1株假结核株、 1株大肠杆菌埃希氏菌进行检测并作比较。结果显示经噬菌体裂解试验 82株菌均在 18～ 2 0 h显示出噬菌斑 ,而其中 2株聚合酶链反应为阴性 ,另 80株全部为鼠疫菌特异性扩增带 ,比较清晰、典型、稳定 ,它有助于鼠疫菌快速特异诊断     

Detection of linkage under heterogeneity: comparison of the two-locus vs. admixture models.

Linkage analysis under the two-locus model and the admixture model was compared on pedigree data for a common disease stimulated under a model of genetic heterogeneity. The ascertainment of families was designed so that the samples had a large proportion of families segregating for both disease loci. The two-locus linkage analysis model did not demonstrate increased power of detecting linkage or more accurate estimates of the recombination fraction, theta than did the admixture model linkage analysis. When a sample was purposely chosen so that all of the families were segregating for both loci, then the two-locus lod score analysis was better. However, the increased power depended on assuming the correct gene frequency for the linked locus. It can be concluded that under the conditions of genetic heterogeneity examined here, testing for linkage under the admixture model is the preferred method of analysis. However, this is not a general conclusion that can apply to all two-locus disease models.     

The short insulin tolerance test for determination of insulin sensitivity: a comparison with the euglycaemic clamp.

The glucose clamp technique is currently regarded as the standard test for measuring insulin sensitivity against which other methods are compared but is unsuitable for routine screening of patients outside a hospital base. There is thus a need for a simpler test to measure insulin sensitivity. We have therefore compared the glucose disappearance rate KITT in the first 15 min of the insulin tolerance test (ITT) with the M and M/I values derived from the standard euglycaemic clamp in nine normal subjects and eight subjects with Type 2 (non-insulin dependent) diabetes mellitus and coexisting obesity. All subjects underwent the ITT and euglycaemic clamp in random order. Nine subjects later had a repeat ITT to determine the reproducibility of the test. In the ITT, 0.1 U kg-1 body weight, human Actrapid insulin was given as an IV bolus and simultaneous arterialized and venous blood samples were obtained every minute for 15 min. The first order rate constant for the disappearance of glucose KITT over the period 3-15 min was taken as a measure of insulin sensitivity. The euglycaemic clamp was performed with an insulin infusion of 50 mU kg-1 h-1 for 120 min and a variable rate glucose infusion to maintain blood glucose concentration at 0.5 mmol l-1 below fasting level to minimize the effect of endogenous insulin secretion. The ratio of the mean rate of glucose infused (M, mumol kg-1 min-1) to the plasma insulin over the last 30 min of the clamp was taken as a measure of tissue sensitivity to insulin (M/I) assuming endogenous glucose output was suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impaired colour discrimination in Huntington's disease

Colour discrimination and visual contrast perception were investigated in 18 patients with Huntington's disease (HD) and in 18 age- and sex-matched healthy volunteers using the Farnsworth-Munsell 100 Hue test (FM) and stationary contrast targets. The mean total error score (MTES) and the partial scores for the “red-green” and the “blue-yellow” axes in the FM of the patients with HD were significantly elevated as compared to controls (MTES in HD: 113.0 ± 90.8; MTES in controls: 19.2 ± 8.8). The spatial contrast sensitivity in HD patients was normal. The colour perception dysfunction indicates that the visual system is affected in HD. The visual disorder may be related to an imbalance of certain neurotransmitters in the visual system of HD patients. Possible anatomical sites of the dysfunction responsible for colour discrimination abnormalities could be the retinal cone system and/or impaired parvocellular central visual pathways in HD.