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41.
Effects of THA on ionic currents in myelinated axons of Xenopus laevis   总被引:1,自引:0,他引:1  
In voltage-clamp experiments with the myelinated nerve fibre of Xenopus laevis, 9-amino-1,2,3,4-tetrahydroacridine (THA) decreased both Na+ and K+ currents and shifted the steady state inactivation potential curve in a negative direction. The effects may be described as (a) a decrease of the permeability constant PNa, (b) a modified potential dependence of the inactivating system and (c) a decrease of PK. The Na+ system was affected more than the K+ system.  相似文献   
42.
Abstract

Heart auscultation has been recognised for a long time as an important tool for the diagnosis of heart disease; it is the most common and widely recommended method to screen for structural abnormalities of the cardiovascular system. Detecting relevant characteristics and forming a diagnosis based on the sounds heard through a stethoscope, however, is a skill that can take years to be acquired and refine. The efficiency and accuracy of diagnosis based on heart sound auscultation can be improved considerably by using digital signal processing techniques to analyse phonocardiographic (PCG) signals. The study of the functioning of the heart is very important for the diagnosis of different cardiac pathologies. The phonocardiogram signal (PCG) is the signal generated after conversion of the sound noises coming from the heart into an electrical signal, it groups together a set of four cardiac noises (S1, S2, S3, S4) which are in direct correlation with cardiac activity. The short-term Fourier Transform (STFT) is an analytical technique that describes the evolution of the time and frequency behaviour of these four heart sounds. A statistical study has been carried out in this direction in order to better highlight the characteristics of the PCG signal. A fairly high number of cycles (twenty) was used to further refine the expected results. The objective of this paper is to use a statistical analysis based on the results obtained by the use of The STFT technic this in order to find statistical parameters (mean, standard deviation, etc.) which can give us a clear vision of the electrophysiological behaviour of the phonocardiogram signal. This aspect has not been done so far and which however can give appreciable practical results.  相似文献   
43.
The ability to provide the best treatment for breast cancer depends on establishing whether or not the cancer has spread to the lymph nodes under the arm. Conventional assessment requires tissue removal, preparation, and expert microscopic interpretation. In this study, elastic scattering spectroscopy (ESS) is used to interrogate excised nodes with pulsed broadband illumination and collection of the backscattered light. Multiple spectra are taken from 139 excised nodes (53 containing cancer) in 68 patients, and spectral analysis is performed using a combination of principal component analysis and linear discriminant analysis to correlate the spectra with conventional histology. The data are divided into training and test sets. In test sets containing spectra from only normal nodes and nodes with complete replacement by cancer, ESS detects the spectra from cancerous nodes with 84% sensitivity and 91% specificity (per-spectrum analysis). In test sets that included normal nodes and nodes with partial as well as complete replacement by cancer, ESS detects the nodes with cancer with an average sensitivity of 75% and specificity of 89% (per-node analysis). These results are comparable to those from conventional touch imprint cytology and frozen section histology, but do not require an expert pathologist for interpretation. With automation of the technique, results could be made available almost instantaneously. ESS is a promising technique for the rapid, accurate, and straightforward detection of metastases in excised sentinel lymph nodes.  相似文献   
44.
Interleukin-10 (IL-10) is a major immunoregulatory cytokine and has a multitude of immunomodulatory effects in the immune system. In this study, we have examined the secretion andin vitro function of IL-10 in B cell hyperactivity in antibody production in two common autoimmune diseases, systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). IL-10 was detectable in serum of all active SLE and serum and synovial fluid samples of all RA patients but in none of the normal controls. B cells and CD4+CD45RO+ memory T cells secreted highly enhanced levels of IL-10 in SLE and RA versus normals. Increased IgM and IgG production by B cells-CD4+CD45RO+ T cells in SLE and RA was IL-10 dependent, since neutralization of IL-10 cytokine by anti-IL-10 antibody drastically reduced Ig synthesis in these coculture experiments. B cell hyperactivity in autoantibody production in SLE and RA may be a function of IL-10-dependent CD4+CD45RO+ Th2 cell activation. Therefore, IL-10 may play an important role in highly disturbed immune system and B cell-T cell function in these immune disorders.  相似文献   
45.

Background

Hemihyperplasia (hemihypertrophy) is defined as asymmetric body overgrowth of one or more body parts. Hemihyperplasia can be isolated or be part of well-defined syndromes such as in the case of Beckwith-Wiedemann syndrome (BWS). Isolated hemihyperplasia is usually sporadic, but a number of familial occurrences have been described.

Case presentation

We describe a Tunisian family in which three maternal cousins and their maternal grandfather present with isolated hemihyperplasia.

Conclusions

The etiology of isolated hemihyperplasia is unknown although in BWS, genomic imprinting has been shown to play a role in the asymmetric overgrowth. Given the similarity between these two conditions, it is possible that both may share a common pathogenesis. We also discuss the possible genetic mechanisms leading to the production of hemihyperplasia in this family.  相似文献   
46.
Development of pancreatic hepatocytes in adult rats maintained on copper deficient diet containing 0.6% trien (CuDT) has been reported recently. To elucidate the histogenesis of hepatocytes a sequential study was undertaken using morphologic, histochemical, immunochemical, in situ hybridization, and Northern blot analysis. Male F-344 rats weighing 80 to 90 g were fed CuDT for 8 weeks and returned to normal rat chow. Beginning from 4 weeks of copper depletion, there was a progressive loss of acinar cells and by 8 weeks more than 90% of the acinar tissue was lost. During this period, there was an increase in the number of adipocytes in the interstitium, and in the number of interstitial and ductular cells. Morphologic observations were confirmed by immunoblot and Northern blot analysis, in which the amount of pancreatic proteins and their mRNAs decreased between 5 and 8 weeks. During this period, a progressive increase in the level of albumin mRNA was observed. In situ hybridization, performed at 7 weeks of copper deficiency, showed localization of albumin mRNA over interstitial and ductular cells. Pancreatic hepatocytes were identified immediately after the rats were returned to a normal diet and gradually increased in number. The hepatocytes occupied almost 60% of the pancreatic volume by 8 weeks. During the early recovery phase, hepatocytes were identified in ductules as well as in the interstitium. Based on these studies, it is concluded that both the ductular cells and interstitial cells, which resemble oval cells of liver, are capable of transforming into pancreatic hepatocytes and these cells may be considered stem-cell equivalent.  相似文献   
47.
During June and July of 2007, a total of 130 specimens of the fish Rastrelliger kanagurta Cuvier (Teleostei, Scombridae), ranging between 19–31 cm in total length, were caught in the Red Sea off the coast of Sharm El-Sheikh, South Sinai, Egypt, and examined for infections by acanthocephalans (65 fish/month). Of this number, 29 (22.30%) were slightly or heavily parasitized by the acanthocephalan Diplosentis nudus (Harada, 1938) Pichelin et Cribb, 2001 (Cavisomidae); no other helminth parasites were found in the intestine of R. kanagurta. Twenty-nine infrapopulations of D. nudus, ranging from 23–218 individuals were collected from the infected fishes. These infrapopulations were distributed in a well-defined fundamental niche along the intestine of R. kanagurta, where the distribution of male worms was not random with respect to female worms size and position and suggests that the male-male competition for access to female may be intense and may select for large males. No correlation between fish size and infrapopulation size was observed. Correlations between female-to-male sex ratio and infrapopulation size, numbers of females and their mean lengths, numbers of males and their mean lengths, mean female length and mean male length within infrapopulation were very strong, and clearly suggest that as the infrapopulation size increased, the number of females and their mean lengths decreased and the number of males and their mean lengths increased. Combination of these results strongly suggests density-dependent effects and competition between male worms. The relationship between the mean female length or size and the number of eggs within its pseudocoel was strongly positive; egg production by female worm significantly decreases as the infrapopulation size increases, suggesting density-dependent reduction in female worm fecundity. Tendency for the variability in male testes size was not significant in infrapopulations of D. nudus. All of these results are discussed.  相似文献   
48.
49.
Department of Biology and General Genetics, Patrice Lumumba Peoples' Friendship University, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. V. Prozorovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 106, No. 12, 711–714, December, 1988.  相似文献   
50.
Increased Clq binding levels have been obtained in serum from twenty-one (50%) of forty-two patients with cryptogenic fibrosing alveolitis (CFA) suggesting the presence of circulating immune complexes. There was a low frequency of positive results using a number of other tests for circulating immune complexes. The increased Clq binding levels were observed in six (35%) out of seventeen patients with lone lung involvement and in fifteen (60%) out of twenty-five patients with extrapulmonary connective tissue disorders. There was an especially close correlation between arthritis and elevated Clq binding. A strong correlation between Clq binding levels and levels of circulating rheumatoid factor (RF) and IgG, and enhancement in macrophage radiobioassay tests using RF-containing sera, suggested that RF might be involved in the circulating immune complexes in these patients. DNAase pre-treatment of sera did not influence the findings, and there was no correlation between Clq binding and levels of immunofluorescent ANA, C-reactive protein levels, or platelet counts. A weak correlation between Clq binding and erythrocyte sedimentation rates, and slightly lower binding levels in treated than untreated patients with 'lone' CFA suggested that binding levels may give some indication of disease activity and may in some instances be influenced by treatment.  相似文献   
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