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101.
Tumour cell growth may be accelerated by protein kinase C (PKC) agonists
such as phorbol esters and receptor tyrosine kinases, but receptor tyrosine
kinases are in turn desensitized to growth factors by PKC agonists. To
clarify this apparent PKC bifunctionality, we have used phosphoantibodies
to determine the relationship between PKC- dependent phosphorylation events
affecting the ErbB2 oncoprotein in G8/DHFR 3T3 cells. Neither the kinetics
nor the extent of phorbol- induced juxtamembrane domain (Thr686)
phosphorylation vary directly with C-terminal (Tyr1222) dephosphorylation,
with Tyr1222 continuing to be dephosphorylated long after Thr686
phosphorylation has also declined. Platelet-derived growth factor (PDGF)
mimics the short-term effects of phorbol on Thr686 and Tyr1222
phosphorylation, and confocal microscopy reveals that both of these PKC
agonists induce rapid internalization of PKC-modified ErbB2. Phorbol causes
sustained cytoplasmic accumulation of PKC-phosphorylated receptors,
however, whereas PDGF triggers the appearance of this ErbB2 subset only
briefly. Metabolic labelling and co-precipitation studies fail to implicate
heterologous molecules in either the tyrosine dephosphorylation or
internalization of PKC-modified ErbB2. Taken in the context of earlier
juxtamembrane domain mutagenesis studies, these findings indicate that
phorbol-activated PKC may desensitize growth factor receptors to
extracellular ligands solely by triggering sustained receptor
internalization. We submit that PKC-dependent juxtamembrane domain
phosphorylation represents a physiological mechanism for shortening the
duration and enhancing the specificity of growth factor signalling by
promoting internalization of liganded and unliganded receptors,
respectively.
相似文献
102.
103.
104.
Bogaert J Kuzo R Dymarkowski S Janssen L Celis I Budts W Gewillig M 《European radiology》2000,10(12):1847-1854
Regular follow-up is required in patients with previous intervention for coarctation of the aorta to detect recoarctation
or aneurysm formation. In this study we describe the findings encountered on routine follow-up exams and we compare the use
of contrast-enhanced 3D MR angiography (CE MRA) with fast spin-echo MRI (FSE) to study the thoracic aorta after previous intervention.
In 51 consecutive patients previously treated for aortic coarctation, 74 MR studies of the thoracic aorta were performed during
a 2-year period using CE MRA and FSE MRI. The thoracic aorta was evaluated for abnormalities of course, caliber, shape, and
pathology of side branches. The CE MRA and FSE MRI studies were evaluated side by side by consensus of two reviewers evaluating
which MR technique depicted the abnormalities of the thoracic aorta the best. Of 74 exams, six clinically important abnormalities
were found: four aneurysms and two restenoses. Two small pseudoaneurysms were missed on the FSE studies. Contrast-enhanced
MRA was judged to visualize aortic abnormalities better than FSE (47 of 74 MR studies) especially for the transverse aortic
arch, coarctation site, left subclavian artery, and aortic arch configuration. For the ascending aorta and distal descending
aorta, CE MRA and FSE performed equally well. Aortic diameters measured at four levels in the first 18 MRI studies showed
no significant differences in diameter when measured by FSE or CE MRA (p = not significant). Clinically important abnormalities, such as aneurysm formation and restenosis, can be present years after
treatment for aortic coarctation. In the regular follow-up of these patients, CE MRA may provide additional diagnostic information
compared with FSE and should be included as part of the routine exam.
Received: 3 April 2000; Revised: 5 July 2000; Accepted: 7 July 2000 相似文献
105.
106.
Rubio-Gozalbo ME Sengers RC Trijbels JM Doesburg WH Janssen AJ Verbeek AL Smeitink JA 《Neuropediatrics》2000,31(3):114-121
The aim of this study was to assess an optimal screening for paediatric patients suspected of mitochondriocytopathy to justify a muscle biopsy. Forty-five patients were included. Medical history, physical examination, cardiac and ophthalmologic evaluation, clinical chemical investigations, in vivo function tests, neuroimaging and a skeletal muscle biopsy were performed in all patients. The results of the biochemical muscle studies were compared with the results of the other investigations. First, parameters with a statistical relationship with the result in muscle, normal or deficient, were selected. Secondly, a prognostic index was constructed using these parameters. Five parameters were selected: age <4 years, elevated fasting lactate to pyruvate ratio, elevated thrombocyte count, elevated lactate, and elevated alanine. Each parameter was scored 0 (not present) or 1 (present). The chance of a normal biopsy with a given value of this index (sum of the scores) was calculated: logit (Pr) = alpha + beta x index; alpha: -0.8167 and beta: 0.8331. (Pr: probability of normal biopsy.) The chance of a normal biopsy with an index value of 5 is 0.03, 4 is 0.07, 3 is 0.16, 2 is 0.30, 1 is 0.50 and 0 is 0.69. This prognostic index is a valuable instrument in deciding whether the suspicion of mitochondriocytopathy is strong enough to merit a muscle biopsy. 相似文献
107.
108.
Boström J Janssen G Messing-Jünger M Felsberg JU Neuen-Jacob E Engelbrecht V Lenard HG Bock WJ Reifenberger G 《Journal of neurosurgery》2000,93(2):335-341
The authors report on an 11-year-old boy in whom proptosis of the eye caused by a benign intraosseous xanthofibroma of the left orbital wall became clinically apparent at the age of 4 years. Two years later he developed bilateral papilledema, at which time computerized tomography and magnetic resonance studies revealed multiple enhancing intracranial lesions. The largest mass was located in the left middle fossa; other lesions were located at the tentorium cerebelli, in both lateral ventricles, near the superior sagittal sinus, and extracranially near the left jugular vein. The mass in the left middle fossa was resected and diagnosed as juvenile xanthogranuloma (JXG). Thirty months later, the patient again became symptomatic, exhibiting behavioral abnormalities and a decrease in mental powers. At that time, the two remaining lesions in both lateral ventricles had grown enough to cause trapping of the temporal horns and raised intracranial pressure. These lesions were successively resected and histopathologically confirmed to be JXGs. However, resection of the second intraventricular lesion was complicated by postoperative bilateral amaurosis, presumably caused by postdecompression optic neuropathy. According to a review of the literature, fewer than 20 patients with JXG involving the central nervous system have been reported. The patient described in this report is the first in whom multiple intracranial JXGs developed in the absence of cutaneous manifestations. Although JXGs are biologically benign lesions, the treatment of patients with multifocal and/or progressive intracranial manifestations is problematic. 相似文献
109.
Real‐world medical costs of antiviral therapy among patients with chronic HCV infection and advanced hepatic fibrosis
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110.
Amy D. Lykins Erick Janssen Sarah Newhouse Julia R. Heiman Eshkol Rafaeli 《The journal of sexual medicine》2012,9(5):1360-1366
IntroductionDespite the importance of sexuality for romantic relationships, there has been little research attention to individual differences and dyadic variables, including couple similarity, and their association with sexual problems and satisfaction.AimThe current study examined the effects of the propensity for sexual inhibition and sexual excitation scales (SIS/SES) and the effects of different mood states on sexuality (Mood and Sexuality Questionnaire [MSQ]), at both the individual and the dyad level, on sexual arousal problems and sexual satisfaction.MethodsSimilarity in SIS/SES and MSQ was measured in a nonclinical sample of 35 newlywed couples and operationally defined as the within‐couple, z‐transformed correlations between the two partners' item responses.Main Outcome MeasuresSexual arousal problems were assessed using self‐report measures (Demographic and Sexual History Questionnaire) and focused on the past 3 months. Sexual satisfaction was assessed using the Global Measure of Sexual Satisfaction.ResultsRegression analyses revealed that greater similarity in the effects of anxiety and stress on sexuality was associated with more reported sexual arousal problems of wives. In contrast, the husbands' sexual arousal problems were related only to their own higher SIS1 scores. Higher SES scores predicted lower sexual satisfaction for both husbands and wives. Wives who reported strong positive mood effects on their sexuality indicated greater sexual satisfaction, while husbands who were more similar to their wives in the effect of positive moods on sexuality indicated greater sexual satisfaction.ConclusionsThe findings show that, above and beyond one's own sexual propensities, similarity in various aspects of sexuality predicts sexual problems (more so in women) and sexual satisfaction (in both men and women). Lykins AD, Janssen E, Newhouse S, Heiman JR, and Rafaeli E. The effects of similarity in sexual excitation, inhibition, and mood on sexual arousal problems and sexual satisfaction in newlywed couples. J Sex Med 2012;9:1360–1366. 相似文献