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Forty-three men underwent varicocele scintigraphy to exclude underlying varicocele as a possible cause of decreased semen quality. The total acquisition time for each study amounted to as little as 200 seconds. In four cases retrograde blood flow was seen in the left internal spermatic vein, with subsequent clear visualization of the pampiniform plexus. In three of four of these patients, pregnancy ensued after therapeutic intervention. Seven patients showed only increased scrotal activity locally, in the absence of retrograde blood flow. The remaining 32 patients showed a normal blood flow pattern. The existence of spermatic vein reflux in varicocele-related infertility is thought to be a major factor in proper patient selection for therapeutic ligation or embolization of the internal spermatic vein. It is suggested that this simplified scintigraphic method may be useful in the detection of retrograde blood flow in patients with varicocele, especially in small or subclinical varicocele.  相似文献   
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In comparison to the well characterized role of the principal subunit of voltage-gated Ca2+ channels, the pore-forming, antagonist-binding alpha1 subunit, considerably less is understood about how beta subunits contribute to neuronal Ca2+ channel function. We studied the role of the Ca2+ channel beta3 subunit, the major Ca2+ channel beta subunit in neurons, by using a gene-targeting strategy. The beta3 deficient (beta3-/-) animals were indistinguishable from the wild type (wt) with no gross morphological or histological differences. However, in sympathetic beta3-/- neurons, the L- and N-type current was significantly reduced relative to wt. Voltage-dependent activation of P/Q-type Ca2+ channels was described by two Boltzmann components with different voltage dependence, analogous to the \"reluctant\" and \"willing\" states reported for N-type channels. The absence of the beta3 subunit was associated with a hyperpolarizing shift of the \"reluctant\" component of activation. Norepinephrine inhibited wt and beta3-/- neurons similarly but the voltage sensitive component was greater for N-type than P/Q-type Ca2+ channels. The reduction in the expression of N-type Ca2+ channels in the beta3-/- mice may be expected to impair Ca2+ entry and therefore synaptic transmission in these animals. This effect may be reversed, at least in part, by the increase in the proportion of P/Q channels activated at less depolarized voltage levels.  相似文献   
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University of Texas M. D. Anderson Cancer Center cases filed as Hurthle cell and follicular carcinoma were reviewed. Requirements for including a case in the study were that the diagnosis of Hurthle cell or follicular carcinoma be confirmed, that histologic material and clinical information be adequate, and that there be at least 9 years of follow-up. The study group included 18 cases of Hurthle cell carcinoma and 33 cases of follicular carcinoma. Ten of the Hurthle cell carcinomas had extrathyroid invasion, three had intrathyroid invasion, and five were encapsulated (i.e., they had intracapsular invasion only). In the follicular carcinoma group, 5 tumors had extrathyroid invasion, 14 had intrathyroid invasion, and 14 were encapsulated. When the cases were stratified according to extent of invasion in this manner, there was no statistically significant difference in rate of local recurrence, rate of metastasis (either regional lymph node or distant), or patient survival between Hurthle cell carcinoma and follicular carcinoma. Other variables including patient age and sex, treatment differences, tumor size, vascular invasion, predominant growth pattern (follicular versus solid-trabecular), nuclear size and pleomorphism, mitotic rate, and tumor necrosis did not provide significant additional prognostic information. Metastases of both Hurthle cell and follicular carcinoma were mostly distant and predominantly involved bone and lung. Behavioral differences between Hurthle cell and follicular carcinoma that were not statistically significant included a higher rate of local recurrence in Hurthle cell carcinoma with intrathyroid invasion, more frequent occurrence of regional lymph node metastasis in Hurthle cell carcinoma with extrathyroid invasion, and absence of distant metastasis and death caused by tumor in encapsulated Hurthle cell carcinoma. Five follicular carcinomas and one Hurthle cell carcinoma appeared to have arisen within an adenoma.  相似文献   
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Yttria-doped zirconia (YDZ) thin films with nanometric sized grains were prepared by reactive RF sputtering and their oxygen ion conductivities were systematically measured as a function of yttria doping with levels in the range 0.5–9.1 mol.% Y2O3. Enhanced oxygen ion conductivities, as derived from impedance spectra, were observed when compared with values reported for bulk YSZ. Furthermore, the peak conductivity for the YDZ films was observed to occur at considerably reduced yttria levels, i.e., at 6.5 mol.% Y2O3 (for T > ~400 °C) and at 3.2 mol.% Y2O3 (for T < ~300 °C) vs. 9 mol.% Y2O3 in bulk YSZ. Based on an analysis of the Raman spectra, these results are believed to result from the extended meta-stability of the cubic phase to reduced yttria levels at nanometric grain sizes.  相似文献   
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If one listens to a meaningless syllable that is repeated over and over, he will hear it undergo a variety of changes that can be described systematically in terms of reorganization of the phones constituting the syllable and changes in a restricted set of phonetic distinctive features. When the repeated syllable is followed by a different syllable but in the same voice, the new (test) syllable will be misperceived in a manner related to the perceptual misrepresentation of the repeated syllable. In the present experiment subjects (N = 24) listened to 72 different experimental sequences of repeated syllables in a male voice followed by test syllables in a female voice. Identification of penultimate and test syllables was independent and in no instance were the phone constituting the syllables reorganized. These results are interpreted as evidence against both auditory and phonetic feature detector theories of speech perception.  相似文献   
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