Digital image ratio: a new radiographic method for quantifying changes in alveolar bone. Part 1: theory and methodology

A new method, digital image ratio (DIR), has been developed for directly measuring changes in alveolar bone. The image on the computer monitor represents the relative mass change between two radiographs. Fourier filtering is used to reduce noise artefacts. This method is validated through an experiment with a step wedge. DIR needs only a preliminary calibration of the experimental conditions of operation and avoids tedious calibrations for each measurement as in the case of digital image substraction. Low-voltage X-ray techniques are suggested for long-term quantitative studies of patients to minimize irradiation doses.     

High speed bolus tagging: time resolved velocity quantification of pulsatile flow in a single breath hold

We have implemented a high speed method for cardiac-trig gered blood velocity quantification within a single breath hold on a conventional MR system. The method, based on bolus tagging, was tested using a pulsatile flow phantom and evaluated in vivo. The image acquisition time was reduced by a factor of N by acquiring N phase encode lines per bolus tag application. The clarity of the flow tag was found to vary with how k-space was covered during data collection. The technique was optimized and multiple bolus tag images were obtained throughout the cardiac cycle within a single breath-hold.     

Choice of reference region in the quantification of single-photon emission tomography in primary degenerative dementia

This study evaluated the effect of using two different reference regions in the quantification of single-photon emission tomography (SPET). SPET scans of 30 patients with Alzheimer's disease (AD) and 30 patients with frontotemporal dementia were compared with the scans of ten age-matched controls. Regions of interest (RO1s) were defined on transaxial slices by a semi-automatic method. Regional cerebral blood flow indices (rCBFi) in each R01 were determined by normalizing the count densities to both cerebellar and occipital cortex reference regions. Mean rCBFi for each ROI were calculated for the patient and control groups and significant group differences determined. The number and topographical distribution of ROIs with significant group differences varied depending upon the choice of reference region. The magnitude of these differences was greatest when the cerebellum was used as the reference region. The disparity between results obtained with the two reference regions was most apparent in the AD group. The reasons for these differences are discussed and we conclude that the cerebellum is the more appropriate choice of reference region in the quantification of SPET in primary degenerative dementia.     

The detergent scrub method for quantitative determination of Malassezia furfur on chest and back skin: comparative evaluation of three different media

The quantitative determination of Malassezia furfur on normal human skin has been considered as difficult until recently. During the last years, however, several different media have been described which facilitate the quantification of M. furfur. As the efficacy of these media is still controversial, three different media were compared analyzing the chest and back of 20 healthy young adult volunteers. The highest counts of colony-forming units (CFU) per cm2 were found using a medium containing whole fat cow's milk as a major ingredient. At the chest the mean count read was 259, at the back 322. The corresponding figures related to other media were markedly lower (P less than 0.001). Hence, the use of the milk-containing medium for cultivation of M. furfur seems advisable for therapeutic trials.     

Effect of the richness of the environment on the cat visual cortex

In a recent study of the cat visual cortex, it was shown that there are interindividual differences in the numerical density (Nv) of symmetrical synapses associated with flat vesicles (FS synapses) but not of asymmetrical synapses associated with round vesicles (RA synapses). Since many of the environment-sensitive properties of visual cortex neurons are GABA-dependent, it was suggested that the interindividual differences in FS synapses might be due to environmental factors. To verify this possibility we estimated the Nv of both types of synapses in two groups of six cats, paired by litter and by sex, and raised either in isolation or in a colony from the time of weaning to the age of 8 months. We also measured the Nv of neurons and the thickness of the cortex and made some gross anatomical measurements. The brains of animals raised in the enriched environment are 7% heavier, and their total body weight is 10% greater: The brain-to-body-weight ratio remains unchanged. The total length of the brain is not affected, but the length and width of the cerebral hemispheres are each 5% greater in the enriched cats. As in comparable rat studies, the thickness of the cortex is 4% greater, but in the present study this difference is not significant. The numerical density of neurons is diminished by 17% in enriched animals. This is probably due to a wider separation of neuronal cell bodies in a larger cortical volume, rather than to a loss of neurons. There are no significant changes in the numerical density of RA synapses between the two milieux, but there are nearly twice as many FS synapses per mm3 of tissue in the impoverished cortex. The coefficient of variation of FS synapses, which in the previous study was on the order of 30%, has been reduced to 10% and 7% in enriched and impoverished cats, respectively. We conclude that environmental conditions can lead to selective interindividual differences in the Nv of FS synapses, as seen in our previous study of animals whose rearing conditions were not controlled. The average diameter of RA synaptic profiles is not affected by the environment but FS synapses are 25% wider in the enriched animals. Because of the smaller neuronal Nv in enriched animals, there are, in fact, 18% more RA synapses and 34% fewer FS synapses per neuron in the enriched condition.(ABSTRACT TRUNCATED AT 400 WORDS)     

神经肌肉疾病骨骼肌结构与功能的定量超声研究进展

神经肌肉疾病（NMDS）危害影响大,可累及包括运动神经元和感觉神经元,肌肉本身或神经肌肉接头,临床表现为运动系统或神经系统受损相关的多种综合征或畸形,例如肌肉萎缩、肌肉营养不良等。以往NMDS的诊断主要依靠血清肌酸激酶（creatine kinase,CK）水平的测定、肌电图与神经传导速度的测量、基因检测以及肌肉活检。CK诊断肌营养不良症者灵敏度较高但特异性不足,肌电图与神经传导速度的测量、基因检测以及肌肉活检推广应用受局限。近年来,随着高频超声的发展,超声技术在疑似神经肌肉疾病诊断评估中的应用价值被广泛认可,相对于其他影像学技术来说,具有无创、无痛、无辐射的独特优势,可用于床旁,并可以动态观察骨骼肌肉系统的运动特征。越来越多的证据表明,骨骼肌超声是一种良好的生物标记,可以在肌肉疾病诊疗过程中随时间推移跟踪组织形态学、血流灌注、弹性质地变化,然而基于肌肉超声不可避免的各向异性伪像、操作者主观局限性,探索定量超声将有助于为NMDS中骨骼肌结构与功能提供客观可靠的诊断评估方法。     

High-Resolution Light and Electron Microscopic Immunocytochemistry of Colocalized GABA and Calbindin D-28k in Somata and Double Bouquet Cell Axons of Monkey Somatosensory Cortex

A simple method for high-resolution immunocytochemical colocalization of different antigens in semithin sections 1 - 3 μm thick was used to study the colocalization of the calcium binding protein calbindin D-28k (calbindin) with γ-aminobutyric acid (GABA) in double bouquet cells of monkey (Macaca fuscata) somatosensory cortex. Double bouquet cells were first visualized in vibratome sections by pre-embedding immunocytochemical staining for calbindin. Sections containing calbindin-immunoreactive somata and double bouquet cell axons were then osmicated, embedded in Araldite, resectioned at 1–3μm and stained for GABA by postembedding immunocytochemistry after elution of the bound anti-calbindin antibodies. Other semithin sections adjacent to those eluted and still containing calbindin immunoreactive somata and processes were resectioned at 60–70 nm for electron microscopy and stained immunocytochemically for GABA by the postembedding immunogold procedure. Calbindin-positive cells are most numerous in layer II and upper layer III, where they outnumber those in all other layers combined. In layers II and upper III, -30% of the stained cells are pyramidal and do not colocalize GABA. Only approximately two-thirds of the calbindin-stained nonpyramidal cells in these layers colocalize GABA, but among these virtually all the calbindin-positive double bouquet cells and their axons are GABA-immunoreactive. In deeper layers all calbindin-positive cells are nonpyramidal and all colocalize GABA. At the electron microscopic level, however, significant numbers of calbindin-positive axon terminals making symmetrical synapses are not GABA-immunoreactive. These results suggest the calbindin cells of monkey somatosensory cortex are a heterogeneous population that includes GABAergic and non-GABAergic cell types.