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At least 469 records · Page 26Linked to original sources
PubMed1991

Cross-correlation analysis of multi-unit EMG recordings in man.

This paper discusses the measurement of synchrony between 2 multi-unit EMG recordings. The suitability of a number of previously described indices of synchrony is reviewed. A new index of synchronisation is proposed. This index is independent of the number of units contributing to the correlogram but is dependent upon their firing frequency and upon the bin width of the correlogram. The autospectral density function calculated from each multi-unit record is used to estimate motor unit firing rates. The relationship between the frequency of firing and the chosen index of synchronisation is reciprocal such that if the firing rate is doubled, the index is halved. This may be explained if the proportion of events that is synchronized remains constant and is independent of the firing rate. It is argued that this in turn indicates that the proportion of common and non-common sources driving the neurons also remains unchanged in these experiments. In these circumstances, and to take into account changes in unit firing that may be present in different recordings, it is convenient to normalize an experimentally determined index E/M at a frequency f to some standard frequency fs. The problem of superimposition of spikes that occurs as the contraction strength is increased is discussed.

Adult↗
PubMed1988

Electrophysiology and ultrastructure of mouse hypothalamic neurons in culture: a correlative analysis during development.

The development of the electrical activity of hypothalamic neurons in dissociated cell cultures obtained from 14 day old mice foetuses was studied using patch extracellular and intracellular recording techniques. Electrophysiological data were compared with morphological observations obtained by electron microscopy. During patch recording, excitability of the cells was tested by the application of a 40 mM KCl solution. Tetrodotoxin (TTX, 10(-6) M in the delivery pipette) and Co2+ (10(-2) M in the delivery pipette) were applied to the recorded cell by pressure in order to study the involvement of sodium and calcium currents in the electrical activity during the in vitro development. From the first day of incubation, TTX and Co2+ were able to block reversibly the spontaneous electrical activity. However, only TTX application inhibited action potentials which suggests that calcium currents could be poorly involved in the action potential generation at the beginning of neuronal differentiation. Three different phases were found in the electrophysiological development of hypothalamic neurons in culture. The first phase (between the 1st and the 5th day of incubation) was characterized by an increase in the ratio of the spontaneously active cells (15% at day 1 and 90% at day 5). This increase paralleled the increase of the ratio of excitable cells. During this period no post-synaptic activity was detected. Morphologically, at 36 h, no synaptic contact was observed and growth cones were found to be very primitive. The second phase, between the 6th and the 9th day of culture, was characterized by a decrease in the ratio of spontaneously active cells and by the appearance, in a few cases, of a postsynaptic potential activity. During this phase the majority of the silent cells were excitable. At this stage neurons formed well differentiated neurites and growth cones. Synaptogenesis had already started and several stages of synapse formation could be seen. The third phase of the development, from 10 days of incubation, was characterized by an increase in post synaptic potential activity. During this period, numerous mature synapses could be observed although most of the synaptic contacts were located on neurites. In addition, some synapses were apposed onto degenerated structures. In conclusion, hypothalamic neurons in culture appear to differentiate in 3 steps: a primitive stage during which spontaneous electrical activity and excitability develop without any synaptic contact; a 2nd stage during which synaptic contacts develop, followed by a third stage of synapse maturation where mature synapses are formed whereas transient synapses degenerate.

Action Potentials↗
PubMed2026

HER2DX genomic assay in HER2-positive early breast cancer treated with trastuzumab and pertuzumab: A correlative analysis from a real-world cohort.

BACKGROUND: HER2DX genomic assay is a genomic tool developed for personalizing care in early-stage HER2-positive breast cancer. This real-world analysis examines its associations with pathological complete response (pCR) and invasive disease-free survival (IDFS) following trastuzumab- and pertuzumab-based neoadjuvant therapy. MATERIALS AND METHODS: Retrospective, observational, single-center study of 156 patients with stage I-III HER2-positive breast cancer treated with dual HER2 blockade-based neoadjuvant therapy between February 2015 and May 2022&#x202f;at University Hospital A Coru&#xf1;a. HER2DX and clinicopathological variables were assessed in pretreatment tumor biopsies. Statistical analyses included Fisher's exact test, logistic regression, Cox proportional hazards models, and Kaplan-Meier estimates. RESULTS: HER2DX was performed in 111 tumors (71.2%). Overall pCR rate was 51.3%. Hormone receptor-positive disease was significantly associated with lower pCR (odds ratio [OR] 0.25, 95% CI 0.11-0.50; p&#xa0;<&#xa0;0.001), whereas HER2 immunohistochemistry 3+ showed a non-significant trend toward higher pCR (OR 2.95, 95% CI 0.96-11.08; p&#xa0;=&#xa0;0.075). Median IDFS was not reached, but hormone receptor-positive tumors showed better outcomes (hazard ratio [HR] 3.67, 95% CI 1.02-13.32; p&#xa0;=&#xa0;0.004 by log-rank). The association between HER2DX pCR score and pCR appeared heterogeneous. The continuous score was significantly associated with pCR in univariable analysis, not in multivariable model. In contrast, medium-high HER2DX pCR category showed significantly higher pCR rates than low category (OR 4.83, 95% CI 1.72-14.65; p&#xa0;=&#xa0;0.004). The continuous HER2DX risk score was independently associated with IDFS (HR 2.84, 95% CI 1.24-6.48; p&#xa0;=&#xa0;0.010). CONCLUSIONS: In this cohort, HER2DX scores were associated with pCR and IDFS, supporting previous evidence and highlighting potential role in treatment stratification.

Humans↗
PubMed1985

Biological characterization of human bone tumors. V. Zonal characterization of osteosarcoma: topological biochemical analysis correlated with morphology.

Human osteosarcoma specimens were sliced in a cryomicrotome under strict morphological guidance. Serial sections of ten 10 micron slices each were collected in two groups according to morphologic criteria, one containing mostly undifferentiated tumor tissue, the other predominantly well-differentiated tumor tissue. The two series were analysed chemically for alkaline phosphatase (APase) acid phosphatase (acPase), beta-glucuronidase and proteolytic activities; protein, phosphorus, hydroxyproline, hexosamine, water and collagen contents were also determined. Four different types of osteosarcoma were studied: case 1 was a highly malignant osteoblastic osteosarcoma, case 2 a small cell sclerosing osteosarcoma case 3 a well-differentiated osteosarcoma, and case 4 a highly malignant anaplastic osteosarcoma. The types of cases 1, 2 and 3 are known as osteoid-forming tumors. In their less well differentiated areas APase activity was about twice as high as in better differentiated osteosarcoma. In contrast, no APase was found in the wholly undifferentiated areas of case 4, while the enzyme showed a marked increase in the areas of incipient differentiation of this tumor. The matrix of tumors differs with regard to collagen and hexosamine contents, in accordance with the general state of differentiation. In general, increasing hexosamine contents together with decreasing hydroxyproline contents will reflect the anaplastic, dedifferentiated osteosarcoma. Calcification evident in the better differentiated areas of osteosarcoma is indicated by the phosphorus content, highest in case 2, with cases 3, 1, and 4 following in sequential order.

Acid Phosphatase↗
PubMed2006

Correlation analysis of economic traits in Liaoning new breed of cashmere goats using microsatellite DNA markers.

The economic traits of Liaoning new breed of cashmere goats, a special Chinese genetic resource, were analyzed in 150 animals by typing 11 microsatellite loci. The association between three economic traits (body weight, cashmere yield and fineness) in this new breed of goats and the marker genotypes were analyzed. The results show that: AA and BC at LSCV13, DE at IDVGA64 and BB at BMS2782 were favorable genotypes for body weight. AB at LSCV13, AD and BE at CSSM11, BD and CC at IDVGA64, BC and DE at BMS2782 were favorable genotypes for cashmere yield. AA at CSSM11, BC and DE at IDVGA64, CD at BMS2782 were favorable genotypes for cashmere fineness.

Animals↗
PubMedDate not supplied

Echo correlation analysis and the acoustic evidence in the Kennedy assassination revisited.

A Dallas Police Department recording contemporaneous with the Kennedy assassination contains five impulsive sounds that have the acoustic waveform of Dealey Plaza gunfire. One of the sounds matches the echo pattern of a test shot fired from the Grassy Knoll. The shock wave precedence associated with this pattern is consistent with the muzzle velocity of a .30 calibre rifle. Criticism of the acoustic identifications on statistical grounds is based on erroneous assumptions concerning the assignment of values to the parameters that determine the probability that random noises could resemble gunshot patterns. A conservative estimate of the true value of the probability that the putative Grassy Knoll shot is attributable to random radio noise is no greater than 0.037. Alleged asynchroneity of the sounds with the time of the assassination stemmed from several incorrect assumptions. Whatever their origin, the gunshot-like sounds occur exactly synchronous with the time of the shooting.

Journal Article↗