Platelet count, spontaneous platelet aggregation, ADP- and collagen-induced platelet aggregation platelet adhesion, platelet volume, shape change, beta-thromboglobulin and von-Willebrand-factor have been investigated in 51 insulin dependent diabetic children without clinical signs of diabetic angiopathy. Compared to an age matched healthy control group diabetic children showed a significant enhancement of spontaneous platelet aggregation, elevated plasma levels of von-Willebrand-factor, increased platelet shape change and adhesion. No alterations could be found in ADP--and collagen--induced platelet aggregation and in beta-thromboglobulin levels. Significant correlations could be found between the total glycosylated haemoglobin concentrations (Hb A1) and spontaneous platelet aggregation, as well as between duration of diabetes Hb A1, and platelet volume. In this study we could demonstrate changes in platelet function in diabetic children without clinical signs of diabetic angiopathy. However these changes could be due to metabolic adjustment and may precede diabetic vasculopathy. 相似文献
Background: It has been suspected that synthetic colloids may interfere with leukocyte adhesion by down-regulation of endothelial cell adhesion molecules. Although inhibition of endothelial inflammation might reduce leukocyte-related tissue injury, the same mechanism may be detrimental for host defense during severe infection. Regarding the widespread use of colloids, the authors performed a laboratory investigation to determine the mechanisms by which synthetic colloids interfere with leukocyte-endothelial interactions.
Methods: Adhesion molecule expression on native and cytokine-activated endothelium from umbilical veins was measured after pretreatment with gelatin and various preparations of dextran or hydroxyethyl starch. Inhibition of neutrophil adhesion to activated endothelium was examined in a flow chamber by perfusion of untreated and colloid-treated neutrophils over colloid-pretreated endothelium at 2 dyn/cm2. Comparisons were made between untreated controls, colloid-pretreated endothelium, and colloid-cotreated neutrophils.
Results: Intercellular adhesion molecule 1, vascular cell adhesion molecule 1, E-selectin, and P-selectin were not attenuated by any colloid. Accordingly, colloid pretreatment of endothelium alone did not reduce neutrophil adhesion. In contrast, when neutrophils were cotreated by addition of colloids to the perfusate immediately before perfusion, adhesion decreased by 31-51% (P < 0.05) regardless of the colloid type. As indicated by the twofold increased rolling fractions, this reduction was due to an inhibition of neutrophil integrins. 相似文献
The tick-borne Thogoto virus (THOV) is the type species of a newly recognized fourth genus, Thogotovirus, in the family Orthomyxoviridae. Because of the distant relationship of THOV with the influenza viruses, determination of its genomic information can potentially be used to identify important domains in influenza virus proteins. We have determined the complete nucleotide sequence of the second longest RNA segment of THOV. The molecule comprises 2212 nucleotides with a single large open reading frame encoding a protein of 710 amino acids, estimated Mr 81 284. The protein shares 77% amino acid similarity with the PB1-like protein of Dhori virus, a related tick-borne virus, and 50–53% with the PB1 polymerase proteins of influenza virus A, B and C. All the motifs characteristic of RNA-dependent polymerases were identified including the SSDD motif common to all RNA-dependant RNA polymerases, indicating that the THOV protein is functionally analogous to the influenza virus PB1 proteins and involved in chain elongation. We also report the corrected sequence of the third longest RNA segment of THOV, encoding a protein which shares 44–47% amino acid similarity with the PA-like polymerase proteins of influenza virus A, B and C. The biological significance of conserved domains in these orthomyxovirid proteins is discussed. 相似文献
The material consists of a series of 73 patients with squamous cell carcinoma of the vulva. The site and the size of the primary tumor and the histological status of the lymph nodes of the groin were known. Two pathologists evaluated nuclear hyperchromatism, nuclear polymorphism, histological differentiation, number of mitoses, inflammatory response, and vascular invasion and graded these parameters from one to three. The reliability of the histopathological grades evaluated by the κ coefficient showed considerable interobserver variation. Despite this a model which included the subjective parameter nuclear hyperchromatism could predict patients without lymph node metastases. The model consisted of patients with tumors which were not situated on the clitoris, were less than 40 mm in diameter, and exhibited only slight hyperchromatism. The model fitted 19 (26%) and 14 (19%) of the patients with two different pathologists evaluating the nuclear hyperchromatism and none of these patients had lymph node metastases. The quantitative parameter—mean nuclear volume—determined by morphometry was of no diagnostic value for the prediction of patients without groin node metastases at the time of operation. 相似文献
Information processing in the nervous system is achieved primarily at chemical synapses between neurons. Recent evidence suggests that glia-neuron interactions contribute in multiple ways to the synaptic process. In the present study we used the frequency of spontaneous postsynaptic currents (sPSC) in Purkinje neurons in acute cerebellar brain slices from juvenile rats (13-19 days old) as a measure of synaptic activity. Following 50 depolarizing pulses to an adjacent Bergmann glial cell (50 mV; duration 0.5 s; 1 Hz) the sPSC frequency of the Purkinje neuron was reduced to 65 ± 7 % of control values within 10 min after glial stimulation and remained depressed for at least 40 min. Depolarizing pulses to 0 mV had a comparable effect (70 ± 5 % of control). The frequency of miniature PSCs, as recorded in 300 n m TTX, was not modulated after glial stimulation. Blockade of ionotropic glutamate receptors (iGluRs) with kynurenic acid (1 m m ) or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 5 μ m ) suppressed the reduction of neuronal activity induced by glial depolarization, whereas the glial modulation of synaptic activity was not inhibited by a block of N -methyl- d -aspartate iGluRs, metabotropic glutamate receptors, cannabinoid receptors or GABAB receptors. Fluorometric measurements of the intraglial Ca2+ concentration revealed no glial Ca2+ transients during the depolarization series, and glial cell stimulation reduced the neuronal sPSC frequency even after loading the glial cell with 20 m m of the Ca2+ chelator BAPTA. Our results indicate a glia-induced long-lasting depression of neuronal communication mediated by iGluRs. 相似文献
The frequency of deletion of short arm satellites has been examined in various populations. Four out of 2509 males in psychiatric institutions and prisons had Dps- or Gps- (1·6 per 1000), and five out of 6187 persons in the general population had Dps- or Gps- (0·8 per 1000). The difference is not significant.
The segregation rate of the chromosome with lack of short arm satellite material did not deviate from unity in the few families where such calculations were possible. There was no increase in abortions or non-disjunction in the families with an acrocentric chromosome lacking short arm satellite material.
The study indicates that the frequency of Dps- and Gps- in the population is between 0·5 and 1·0 per 1000 and that the lack of short arm satellite material is without any deleterious effect on phenotype.
Apart from its role in elevating red blood cell number, erythropoietin (Epo) exerts protective functions in brain, retina and heart upon ischaemic injury. However, the physiological non-erythroid functions of Epo remain unclear. Here we use a transgenic mouse line (Tg21) constitutively overexpressing human Epo in brain to investigate Epo's impact on ventilation upon hypoxic exposure. Tg21 mice showed improved ventilatory response to severe acute hypoxia and moreover improved ventilatory acclimatization to chronic hypoxic exposure. Furthermore, following bilateral transection of carotid sinus nerves that uncouples the brain from the carotid body, Tg21 mice adapted their ventilation to acute severe hypoxia while chemodenervated wild-type (WT) animals developed a life-threatening apnoea. These results imply that Epo in brain modulates ventilation. Additional analysis revealed that the Epo receptor (EpoR) is expressed in the main brainstem respiratory centres and suggested that Epo stimulates breathing control by alteration of catecholaminergic metabolism in brainstem. The modulation of hypoxic pattern of ventilation after i.v. injection of recombinant human Epo in WT mice and the dense EpoR immunosignal observed in carotid bodies showed that these chemoreceptors are sensitive to plasma levels of Epo. In summary, our results suggest that Epo controls ventilation at the central (brainstem) and peripheral (carotid body) levels. These novel findings are relevant to understanding better respiratory disorders including those occurring at high altitude. 相似文献