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11.
Melanocortin is the downstream mediator of leptin signaling and absence of leptin signaling in ob/ob and db/db mice revealed the enhancement of bone formation through the central regulation. While alpha-melanocyte-stimulating hormone (alphaMSH) inhibits the secretion of interleukin-1alpha and tumor necrosis factor-alpha from the inflammatory cells, alphaMSH can also enhance clonal expansion of pro B cells linked to stimulation of osteoclastogenesis. Therefore, we tested the effect of melanocortin on bones. alphaMSH analogues [(6)His]alphaMSH-ND and [(6)Asn]alphaMSH-ND were synthesized and the radio-ligand receptor binding- and cyclic AMP generating activity were analyzed in China Hamster Ovary cell line over- expressing melanocortin receptors. The EC(50) of [(6)His]alphaMSH-ND measured from melanocortin-1, 3, 4 and 5 receptors were 0.008 +/- 0.0045, 1.523 +/- 0.707, 0.780 +/- 0.405, and 250.320 +/- 42.234 nM, respectively, and the EC(50) of [(6)Asn]alphaMSH-ND were 16.8 +/- 6.94, 271.8 +/- 21.95, 8.0 +/- 1.21, and 1132.5 +/- 635.46 nM, respectively. Four weeks after the subcutaneous injection of the analogues, the body weights in the [(6)His]alphaMSH-ND and the [(6)Asn]alphaMSH-ND treated groups (346.0 +/- 20.63 g vs. 350.0 +/- 13.57 g) were lower than that of the vehicle treated group (375.8 +/- 17.31 g, p < 0.05). There was no difference in the total femoral BMD measured by dual x-ray absorptiometry among the three groups. Among the three groups, there were no differences in the total numbers of crystal violet positive- or alkaline phosphatase positive colonies, in the expression of Receptor Activator of Nuclear Factor Kappa-B ligand on the tibia and the total number of multinucleated osteoclast-like cells differentiated from primary cultured bone marrow cells. From the above results, no evidence of bone gain or loss was found after treatment of the alphaMSH analogues peripherally. 相似文献
12.
The purpose of this study was to investigate the epidemiologic characteristics of the death by poisoning in Korea. We recoded the Death Certificates Database by injury based on the short version of the International Classification of External Causes of Injuries (ICECI). We evaluated the mortality rate by total injury and poisoning, and analyzed the mortality rate by age, gender, year and month, toxic agent, and intent. Adjusted odds ratios were calculated to evaluate the effects of socioeconomic factors on suicidal poisoning death. The total number of death cases by injury was 346,656. The proportion of death cases by injury decreased from 13.53% of all death cases in 1991 to 11.89% in 2001. However, the mortality rate by poisoning increased rapidly from 1998, and then remained stable. The number of suicidal poisoning deaths has gradually increased, and its mortality rate was 6.41 (per 100,000) in 2001. Major toxic agents were pesticides and herbicides (50.90%) in 2001. Adjusted odds ratios of suicidal poisoning versus other poisonings showed significant differences in education attainment, region, and marital status. In conclusion, the mortality rate by poisoning has increased, and the proportion of suicidal poisoning also has increased compared to that of accidental poisoning. 相似文献
13.
We have treated a total of 16 cases of advanced Kienböck''s disease, stage III and IV by Lichtman''s classification, with triscaphe fusion, tendon ball replacement arthroplasty after excision of lunate, proximal row carpectomy as a salvage procedure and limited wrist fusion, since 1985. All cases were followed for minimal 16 months after each operation. Tendon ball replacement arthroplasty after excision of lunate could not prevent further carpal collapse with persistent chronic wrist pain. The triscaphe fusion or radio-lunate fusion induced a marked limited wrist motion later, and the triscaphe fusion alone was not fit for the treatment of advanced one because of progressive proximal migration of capitate and continuous wrist pain due to ligamentous carpal instability in follow-up. So we tried to simultaneously combine tendon ball replacement arthroplasty after excision of lunate with triscaphe fusion in far advanced Kienböck''s disease, and their end results was favorable. Proximal row carpectomy could be done in far advanced Kienböck''s disease with reasonably painless wrist motions. The overall end results of proximal row carpectomy are much better than any form of carpal arthrodesis. Conclusively the proper way to treat advanced Kienböck''s disease seems to depend on the patient''s age, their job and sex, and the stage of disease. And the cause of wrist pain in advanced Kienböck''s disease seems due to ligamentous carpal instability rather than osteoarthritis on radio-lunate joint. 相似文献
14.
The predominant enzymes responsible for elimination of hydrogen peroxide (H(2)O(2)) in cells are peroxiredoxins (Prxs), catalase, and glutathione peroxidases (GPxs). Evidence suggests that catalytic activities of certain isoforms of these H(2)O(2)-eliminating enzymes are extensively regulated via posttranslational modification. Prx I and Prx II become inactivated when phosphorylated on Thr(90) by cyclin B-dependent kinase Cdc2. In addition, the active-site cysteine of Prx I-IV undergoes a reversible sulfinylation (oxidation to cysteine sulfinic acid) in cells. Desulfinylation (reduction to cysteine) is achieved by a novel enzyme named sulfiredoxin. c-Abl and Arg nonreceptor protein tyrosine kinases associate with catalase in cells treated with H(2)O(2) by mechanisms involving the SH3 domains of the kinases and the Pro(293)PheAsnPro motif of catalase and activate catalase by phosphorylating it on Tyr(231) and Tyr(386). Similarily, GPx1 is activated by c-Abl- and Arg-mediated phosphorylation. The tyrosine phosphorylation is critical for ubiquitination-dependent degradation of catalase. 相似文献
15.
We explore the pursuit in a plane of a target moving at constant slow speed in a straight line. Two models of the pursuit are given. In the continuous case, the pursuer is moving at constant speed and is subject to proportionate angular homeostasis with correction constant b. In the discrete version movement occurs at a constant speed in a sequence of straight line segments of constant length (called the step size, s) the end of the segments being called the vertices. The pattern considered is not the absolute position of the pursuer, but its distance and orientation relative to the target. Both the transients and the asymptotic orbit are addressed. A key quantity is r, the speed of the target expressed as a fraction of that of the pursuer. If the speed of the pursuer is defined as unity, r is also the ratio of the speeds. There exists a critical speed fraction, R(b,s), a function of b and s, that defines what the term slow designates. R(b,s), which has to be found numerically, has the following property. For r less than R(b,s), the asymptotic path is a simple closed curve. In the discrete case the vertices converge to a simple closed curve. The larger r, the more the path (or in the discrete analogue its set of vertices) departs from a circle, and the more eccentric the target is with respect to it. Interest centers on two issues. First we address the transient patterns of the path, notably whether or not the sense of any particular path (clockwise or counterclockwise) is the same throughout, or changes at some stage.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
16.
Effect of stretch on calcium channel currents recorded from the antral circular myocytes of guinea-pig stomach 总被引:7,自引:0,他引:7
Wen Xie Xu Sung Joon Kim Sang Jeong Kim Insuk So Tong Mook Kang Jong Chul Rhee Ki Whan Kim 《Pflügers Archiv : European journal of physiology》1996,432(2):159-164
The effect of membrane stretch on voltage-activated Ba2+ current (I
Ba) was studied in antral circular myocytes of guinea-pig using the whole- cell patch-clamp technique. The changes in cell volume
were elicited by superfusing the myocytes with anisosmotic solutions. Hyposmotic superfusate (202 mosmol/l) induced cell swelling
and increased peak values of I
Ba at 0 mV (from −406.6 ± 45.5 pA to −547.5 ± 65.6 pA, mean ± SEM, n = 8) and hyperosmotic superfusate (350 mosmol/l) induced cell shrinkage and decreased peak values of I
Ba at 0 mV (to −269.5 ± 39.1 pA, n = 8). Such changes were reversible and the extent of change was dependent on the osmolarity of superfusate. The values of
normalized I
Ba at 0 mV were 1.43 ± 0.04, 1.30 ± 0.06, 1.23 ± 0.04, 1.19 ± 0.04, 1 and 0.68 ± 0.06 at 202, 220, 245, 267, 290 and 350 mosmol/l,
respectively (n = 8). I
Ba was almost completely blocked by nicardipine (5 μM) under hyposmotic conditions. The values of steady-state half-inactivation
voltage (−37.7 ± 3.3 and −36.5 ± 2.6 mV, under control and hyposmotic conditions, respectively) or the half-activation voltage
(−13.6 ± 2.3 and −13.9 ± 1.9 mV) of I
Ba were not significantly changed (P > 0.05, n = 6). Cell membrane capacitance was slightly increased from 50.00 ± 2.86 pF to 50.22 ± 2.82 pF by a hyposmotic superfusate
(P < 0.05, n = 6). It is suggested that cell swelling increases voltage-operated L-type calcium channel current and that such a property
is related to the response of gastric smooth muscle to mechanical stimuli.
Received: 14 November 1995/Received after revision and accepted: 8 January 1996 相似文献
17.
Moo -Yeol Lee Hyo -Weon Bang In -Ja Lim Dae -Yong Uhm Sang -Don Rhee 《Pflügers Archiv : European journal of physiology》1994,429(1):150-152
Large conductance Ca2+-activated K+ channel was identified and studied in excised inside-out membrane patches of freshly dispersed smooth muscle cells from rabbit
gastric antrum. The current-voltage relationship of the single channel was linear from -80 to +80 mV of pipette voltage in
which single channel conductance was 249±17.8 pS (n=19) in symmetrical concentration of K+ (145mM) across the patch. Activity of the channel (NPo) depended not only on cytoplasmic calcium concentration but also on
membrane potential. MgATP increased NPo in a dose-dependent manner and Mg2+ was prerequisite for the effect. Okadaic acid (l00nM), inhibitor of protein phosphatases, increased NPo further in the presence
of MgATP. Therefore, it would be concluded that activity of the calcium-activated K+ channel in gastric smooth muscle cells was controlled by phosphorylation state of the channel protein and the state is further
modulated by membrane-delimited protein kinase and protein phosphatase activities. 相似文献
18.
C K Lee Y S Kwak H Rhee Y S Kim J H Han J O Choi Y H Lee 《Journal of Korean medical science》1987,2(1):19-34
The lifetime prevalences of DSM-III mental disorders using Korean version of DIS-III are presented. They were studied in 5,100 adults (aged 18 to 65) in household selected by two stage cluster sampling. Comparisons were made between regions, sex and age groups. International comparison with Epidemiologic Catchment Area program was also made. 相似文献
19.
Spontaneous miniature glycinergic inhibitory postsynaptic currents (mIPSCs) in mechanically dissociated rat sacral dorsal commissural nucleus (SDCN) neurons attached with intact glycinergic presynaptic nerve terminals and evoked IPSCs (eIPSCs) in the slice preparation were investigated using nystatin-perforated patch and conventional whole cell recording modes under the voltage-clamp conditions. Trans-ACPD (tACPD) reversibly reduced the mIPSC frequency without affecting the mean amplitude. The effect was mimicked by a specific metabotropic glutamate receptor (mGluR) II subtype agonist, (2S, 1'S, 2'S)-2-(carboxycyclo propyl) glycine (L-CCG-I), and a specific mGluRIII subtype agonist, 2-amino-4-phosphonobutyrate (L-AP4). These inhibitory effects on mIPSC frequency were blocked by the specific antagonists for mGluRII, alpha-methyl-1-(2S, 1'S, 2'S)-2-(carboxycyclo propyl) glycine and (RS)-alpha-cyclopropyl-4-phosphonophenylglycine. In the slice preparation, eIPSC amplitude and mIPSC frequency were decreased reversibly by L-CCG-I (10(-6) M) and L-AP4 (10(-6) M). In K(+)-free or K(+)-free external solution with Ba(2+) and Cs(+), Ca(2+)-free or Cd(2+) external solution, the inhibitory effect of tACPD on mIPSC frequency was unaltered. Forskolin and 8-Br-cAMP significantly increased presynaptic glycine release, and prevented the inhibitory action of tACPD on mIPSC frequency. Sp-cAMP, however, did not prevent the inhibitory action of tACPD on mIPSC frequency. It was concluded that the activation of mGluRs inhibits glycine release by reducing the action of cAMP/PKA pathway. 相似文献
20.