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1.
C Schmitt J Brachmann W Saggau T Beyer B Waldecker K Scharowski T Hilbel M Montero B Offner W Sch?ls 《Zeitschrift für Kardiologie》1991,80(11):665-672
In 41 patients with recurrent sustained ventricular tachycardia and/or ventricular fibrillation an integrated pacemaker-defibrillator-system (PCD, Medtronic, model 7216 A or 7217 B) was implanted. In 21 out of 24 (88%) patients a new transvenous implantation technique in combination with a subcutaneous patch electrode was used. The implanted devices comprise antibradycardiac pacemaker functions, two different forms of antitachycardiac pacemaker functions (ramp and burst pacing), and internal cardioversion or defibrillation capabilities. During a mean follow-up of 8 months 147 episodes of ventricular tachycardia were detected, 131 of them were terminated successfully by antitachycardiac pacing; in 13 episodes internal cardioversion was applied to revert ventricular tachycardia. Twenty-seven episodes of ventricular fibrillation or rapid ventricular tachycardia (greater than 200/min) were detected and successfully terminated by internal defibrillation. In six patients with intermittent rapid atrial fibrillation, change of antiarrhythmic therapy was required to avoid activation of the device. The new integrated pacemaker-defibrillator systems improve therapy in patients with life-threatening tachyarrhythmias by reducing the number of internal cardioversions/defibrillations; the non-thoracotomy approach reduces the post operative risk. 相似文献
2.
Patient history and clinical examination are important for the diagnosis of degenerative joint disease. Here the typical statements of a patient suffering from early osteoarthritis are described and, as far as possible, explained. The joint in question must be systematically examined. Furthermore, the neighboring joints and soft-tissue structures, i.e., muscles, tendons etc., should be examined and evaluated with respect to their importance in hindering the functional chain. The neuroreflectory mechanisms involved herein are described. 相似文献
3.
Rapid desensitization of the acute stimulatory effects of nicotine on rat plasma adrenocorticotropin and prolactin 总被引:5,自引:0,他引:5
The dose of nicotine and the frequency of its administration appear to be essential determinants of its action on multiple systems including the neuroendocrine regulation of the adrenocorticotropin (ACTH)-corticosterone and prolactin (PRL) axes in the rat. Because desensitization to the acute depressive effects of nicotine has been observed after both acute and chronic administration, these investigations assessed whether desensitization to the stimulative effects of nicotine on ACTH and PRL secretion occurs with repetitive dosing. Extensive dose and time course experiments showed that nicotine rapidly elevates rat plasma ACTH and PRL levels with a threshold dose between 0.1 to 0.25 mg/kg b.wt. i.p. After the stimulation of PRL, levels became significantly depressed. Desensitization to the acute stimulatory effects of nicotine on both hormones was induced by a single dose of nicotine (0.5 mg/kg). One hour later nicotine (1.0 mg/kg) failed to significantly stimulate PRL levels and resulted in a modest increase of ACTH. Desensitization was maximal by 1 hr after the first dose and persisted for at least 6 hr. Adrenalectomy, performed to eliminate corticosterone-induced negative feedback, did not enhance PRL responsiveness to a second dose of nicotine but it partially restored the ACTH response. Pretreatment with corticosterone also failed to modify the PRL response to a single dose of nicotine whereas it partially suppressed the ACTH response. Rapid desensitization to the acute stimulatory effects of nicotine on plasma PRL is independent of glucocorticoid negative-feedback whereas desensitization of the ACTH response is modestly dependent. 相似文献
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5.
In tube-fed patients, dietary fiber is often used to manage constipation/diarrhea. Dietary fiber consists of water-soluble and insoluble plant compounds that are resistant to digestion by small-bowel enzymes but are fermented to varying degrees by colonic bacteria. Many physiologic effects of fiber may be related to the degree of fermentation. Few controlled studies of fiber-containing tube feedings have been performed. These studies have limitations and are nondefinitive as to whether fiber prevents or controls constipation/diarrhea. Constipation in tube-fed patients has not been shown to respond to mixed soluble/insoluble fiber in the few studies performed to date. Likewise, fiber may be of only limited benefit in controlling diarrhea in acute illness because of such factors as stress or medication. Fiber does play a role in maintaining gut integrity in all patients, whether they have diarrhea or not. Fiber may be recommended as part of a standard tube-feeding regimen to help assure gut mucosal integrity but not specifically to treat constipation/diarrhea. Further studies are necessary before the role of fiber in the management of constipation/diarrhea in tube-fed patients is determined. 相似文献
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7.
Eser Tüfek?i Thomas E Merrill Maria R Pintado John P Beyer William A Brantley 《American journal of orthodontics and dentofacial orthopedics》2004,125(6):733-739
Teeth with white spot lesions (WSL) might be more prone to enamel loss during bracket debonding. This in vitro study compared enamel loss from teeth with (n = 14) and without (n = 14) WSL after polishing with low-speed finishing burs or disks (Sof-Lex, 3M ESPE, St Paul, Minn). Debonded surfaces were analyzed with a contact stylus profilometer, and digitized data were compared with baseline readings by using AnSur NT software (Regents, University of Minnesota, Minneapolis, Minn). Specimen surfaces were also examined with a scanning electron microscope. Two-way analysis of variance was performed to analyze the data. In teeth without WSL, the volume losses were 0.16 mm(3) for the bur group and 0.10 mm(3) for the disk group; the mean maximum depths were 47.7 microm for the bur group and 54.3 microm for the disk group. In teeth with WSL, the volume losses were 0.06 and 0.17 mm(3), and the mean maximum depths were 35.1 and 48.7 microm for the bur and disk groups, respectively. There were no significant differences in enamel loss between the 2 groups of teeth without WSL (P =.12). However, in teeth with WSL, the burs removed less enamel than the disks (P = 0.006). Scanning electron microscope examination showed that any damage on the enamel surface was usually located in the cervical third of the teeth. On most specimens, even though tooth surfaces appeared resin-free to the naked eye, there were remnants of it. The differences between groups were so small that they might be clinically insignificant. 相似文献
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9.
Dopamine content and metabolism in mesencephalic and diencephalic cell cultures: sex differences and effects of sex steroids. 总被引:7,自引:0,他引:7
Sexual differentiation of dopaminergic neurons was studied in gender-specific cultures. Dissociated cell cultures were prepared from di- or mesencephalon of gestational day 14 rat embryos and raised in the absence or presence of 17 beta-estradiol or testosterone for up to 13 days in vitro (DIV). Developmental profiles of levels of dopamine (DA) and metabolites as well as capacity for vesicular storage of the transmitter were determined by HPLC. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted. Higher levels of DA were measured in female than in male cultures of both brain regions. In mesencephalic cultures, the differences in DA levels were fully accounted for by sex differences in numbers of TH-IR cells, whereas no sex differences in cell numbers were found in diencephalic cultures. Dihydroxyphenylacetic acid (DOPAC) levels and vesicular storage capacity matured faster in mesencephalic than in diencephalic cultures, but no sex differences were observed. Homovanillic acid (HVA) could not be detected except in 13-DIV mesencephalic cultures. Hormonal treatment did not erase sexual differentiation of dopaminergic neurons. Irrespective of the gender, however, both steroids decreased DA and DOPAC contents in diencephalic cultures but not in mesencephalic cultures. It is proposed that sexual differentiation of dopaminergic systems proceeds in a region-specific fashion and that neurogenesis and development of various parameters of dopaminergic activity may be differentially affected. Sexual differentiation of dopaminergic neurons may be initiated independently of the action of gonadal steroid hormones and may subsequently be modified by differences in hormonal environment. 相似文献
10.
Multiple connexins confer distinct regulatory and conductance properties of gap junctions in developing heart. 总被引:4,自引:0,他引:4
Multiple gap junction proteins (connexins) and channels have been identified in developing and adult heart. Functional expression of the three connexins found in chick heart (connexin42, connexin43, and connexin45) by stable transfection of communication-deficient neuro2A (N2A) cells revealed that all three connexin cDNAs are capable of forming physiologically distinct gap junctions that differ in their transjunctional voltage dependence and unitary channel conductances. The transjunctional voltage dependences of connexin45 and connexin42 closely resembled those of 4-day and 18-day embryonic chick heart gap junctions, respectively. The multiple channel conductances between 80 and 240 pS, including the predominant 160 pS channel, observed in embryonic chick heart were also common to connexin42. The expression of multiple gap junction channels with distinct conductance and regulatory properties within a given tissue may account for developmental changes in intercellular communication. 相似文献