The kinetics of early intermediate processes in the thermal decay sequence following illumination of the bovine visual pigment, rhodopsin, have been studied using flash photolysis. It is found that the conversion of lumirhodopsin497 to metarhodopsin480 I in rod disc suspensions above 0°C can best be interpreted as a second-order process exhibiting pseudo first-order behavior in its terminal stages. The subsequent conversion of metarhodopsin480 I to metarhodopsin380 II is a single first-order process in rod disc suspensions.At low temperatures (from ?40 to ?50°C) the lumirhodopsin497→ metarhodopsin480 I reaction is characterized by relatively large, positive values ofΔH≠ and ΔS≠, white at higher temperatures, above 3°C, this same process has a very small ΔH≠ and slightly negative ΔS≠. In addition the ratios of initial concentrations of the reactants varies by a factor of ~10 in the two temperature ranges studied. The subsequent metarhodopsin 480 I → metarhodopsin 380 II reaction most likely involves rather marked protein configurational changes as indicated by the large, positive values of ΔH≠ and ΔS≠ for this first-order process. 相似文献
BACKGROUND: Combined use of blue dye and radiocolloid is considered to be useful for sentinel lymph node (SLN) biopsy of breast cancer. Whether both techniques together is superior to either alone was analyzed. PATIENTS AND METHODS: A consecutive series of 308 cases of breast cancer who underwent SLN biopsy using the combination technique was used. The frequency of a blue node or hot node was analyzed in all cases and only node-positive cases. Furthermore, the frequency of a blue node and hot node together, or either alone, and the highest radiocount of the SLNs in each case were examined for correlation with 8 clinicopathologic features. Three types of SLN containing both blue dye and radioactivity (blue-hot node), blue dye alone (blue-only node) and radioactivity alone (hot-only node), and the SLN radiocounts were analyzed for correlation with metastatic tumor. RESULTS: Of 308 cases, a blue node was present in 298 (97%), a hot node in 295 (96%), and either a blue or hot node in 306 (99%). The presence of a blue node or hot node was similarly affected by previous surgical biopsy and body mass index (BMI), and the presence of a hot node was also affected by age and tumor location. However, the presence of either a blue node or hot node was not affected by any of these characteristics. Of 77 node-positive cases, 8 (10%), 15 (19%) and 6 (8%) were considered to be node-negative based on blue node, hot node and either blue node or hot node positivity, respectively. The frequency of positivity for SLN metastasis decreased in order from blue-hot, blue-only to hot-only nodes. Of 62 cases with metastatic hot nodes, six (10%) were negative when the hottest node was examined, but the second-hottest node was positive. CONCLUSIONS: The added value of the presence of blue node or hot node was confirmed in the SLN biopsy using the combination technique, which suggests that all blue nodes and hot nodes need to be harvested. 相似文献
Rationale Clinical observations have shown that pain sensitivity is altered in some schizophrenic patients.Objectives To study alterations in pain sensitivity, the ketamine model in schizophrenia research was employed.Materials and methods Rats were subchronically injected with the dissociative anaesthetic ketamine (Ket, ten injections of 30 mg/kg, one injection per day over a period of 10 days). Two weeks after treatment completion, the animals’ pain sensitivity was assayed in the hot plate test and they were subjected to electrical stimulation of the tail root. In addition, the effect of morphine was studied.Results In group-housed animals, there was no difference between Ket-injected animals and control rats as measured in both nociceptive tests. In singly housed Ket-injected rats, pain threshold was increased in the electrical stimulation test. This suggests that stress due to single housing might be essential for modifications of pain sensitivity. Moreover, the antinociceptive effect of morphine was modified after single housing. Interestingly, the effect of morphine on locomotor activity was similar in both groups. In group-housed rats, μ receptor binding was unchanged in the frontal cortex, whereas Ket-injected animals had decreased levels in the hippocampus. In singly housed animals, μ receptor binding in Ket-injected rats increased in the frontal cortex and decreased in the hippocampus. 35S-GTPγ-S binding increased in the frontal cortex in both singly housed groups, but remained unchanged in the hippocampus.Conclusions The data suggest that the ketamine model might be useful for studying altered pain sensitivity in schizophrenia. Moreover, the data suggest that modifications in μ opioid receptor binding contribute to this phenomenon. 相似文献
A randomised, double-blind, cross-over study into the effect of graded sequential mestranol and norethisterone on climacteric symptoms was performed. The study group consisted of 23 post-menopausal women who had previously undergone hysterectomy. Active therapy resulted in a significant reduction in hot flushes and night sweats. There was a slight improvement in insomnia, lack of energy and confidence but the other symptoms were not significantly altered. A small placebo effect was noted but this was only significant 1 mth after active treatment had been discontinued in the group of women receiving placebo second. Active treatment also resulted in a significant reduction in serum sodium, calcium, albumin, alkaline phosphatase and cholesterol, and increase in serum triglycerides, but no alteration in the other biochemical parameters, weight or blood pressure. 相似文献
AIM: To examine whether low-dose and short-term estrogen-replacement therapy (ERT) plus selective serotonin re-uptake inhibitor (SSRI) treatment is effective or not in the treatment of climacteric disorders, hot flashes and depressive symptoms, in oophorectomized women. METHOD: Forty-two oophorectomized women with hot flashes and depressive symptoms were assigned randomly to two groups. We examined the efficacy rates of climacteric disorders, particularly hot flashes and depressive symptoms in 21 women on low-dose ERT (conjugated equine estrogens [CEE] 0.3125 mg/day) and 21 women on low-dose ERT (CEE 0.3125 mg/day) plus SSRI (fluvoxamine 50 mg/day) treated for 8 weeks. We used questionnaires to evaluate the efficacy for depression, namely the Self-rating Depression Scale (SDS) and the Self-rating Questionnaire for Depression (SRQ-D), and for anxiety with the State-Trait Anxiety Inventory (STAI). In the statistical analysis, in the mixed-effect model, for the score against time and adjusted with age, treatment and treatment as the fixed effects. RESULTS: The average scores on the SDS in both groups were decreased by the treatment (P < 0.001). But the efficacy of the ERT + SSRI group in the time x treatment SDS and SRQ-D scores was significantly higher compared with those of ERT (P = 0.0025, 0.0162) and there was a significant difference in the decrease in the frequency of hot flashes by 8 weeks between the two groups (P = 0.036). CONCLUSIONS: A combination of low-dose and short-term ERT + SSRI is more effective than low-dose estrogen alone in relieving the depressive symptoms and hot flashes of oophorectomized women. 相似文献
Summary: Flash conventional heating (FCH) and microwave heating (MH) were matched in their effects on the ROP of ε‐CL catalyzed by Sn(Oct)2. The temperature of the ROP, heated by a hot salt bath, increased from room temperature to 215 °C within 3 min, which rose a little faster than that by MH (213 °C at 6 min), and the way of heating was considered as FCH. The kinetic results indicate that the chain propagation of PCL was significantly accelerated under FCH conditions and the ratio of the chain propagation rate constant by FCH to that by MH (k/k) was 4.48, if the concentrations of their propagating species were the same. The largest number‐average molar mass ( ) of PCL obtained by FCH was 13.0 × 104 g · mol?1 at 6 min, but that by MH was 4.1 × 104 g · mol?1 at 15 min. The ratio of the concentrations of propagating species under the two conditions was around one‐fifth at 4, 6, and 8 min.
Thermal and kinetic behavior of the ROP of ε‐CL. 相似文献
The T-type Ca2+ channel is a low-voltage-activated Ca2+ channel related to nociceptive stimuli. Increases in Ca2+ due to calcium channel activation enhance pain sensitivity through both peripheral and central pain pathways. We have developed a novel compound, KST5468, which is a T-type calcium channel antagonist. The new synthetic compound may have an antinociceptive effect, and thus we evaluated KST5468 as a putative analgesic in a hot plate test, a formalin test, and two neuropathic pain models. KST5468 caused a significant increase in latency in the hot plate test at 30 min after a 10 mg/kg peritoneal injection of the compound. Interestingly, in the second phase of formalin test, KST5468 decreased pain behaviors in a dose-dependent manner. Moreover, in two neuropathic pain models induced by chronic constriction and spared nerve injury, KST5468 significantly increased the mechanical pain threshold. Using immunohistochemistry, expression of two well known pain-related molecular markers, c-Fos and calcitonin gene-related peptide (CGRP), and phosphorylated extracellular signal-related kinase (p-ERK) were found to be decreased in the laminae I-II layers of the ipsilateral L4-L5 spinal dorsal horn in KST5468 treated mice. Taken together, the results of this study suggest that KST5468 may be an effective antinociceptive agent for neuropathic pain. 相似文献