Efficacy of high condylectomy for management of condylar hyperplasia.

The purpose of this study was to compare the treatment outcome and long-term stability of 2 groups of young adult patients diagnosed with active condylar hyperplasia and treated with 2 different surgical methods. Thirty-seven patients (19 females and 18 males) met the criteria for inclusion in the study. Group 1 (n = 12; average age at surgery, 17.5 years) was treated with orthognathic surgery only, while group 2 (n = 25; average age at surgery, 16.7 years) had high condylectomy, articular disc repositioning, and orthognathic surgery. All patients underwent standardized clinical and radiographic examination at initial consultation, immediately before surgery, immediately after surgery, and at longest follow-up. Objective evaluation of temporomandibular joint (TMJ) function included maximum incisal opening and lateral excursions. Subjective evaluations were performed in group 2 for TMJ pain, jaw function, and diet. Lateral cephalometric radiographs were evaluated for presurgical and postsurgical mandibular growth. There were no statistically significant differences (P >.05) between the 2 groups for maximal incisal opening, lateral excursions, or subjective jaw function before surgery. Presurgical growth differed significantly (P <.05), with group 2 showing more active growth. At the long-term follow-up, no differences were found in lateral excursions or subjective jaw function. There was a statistically significant difference in maximum incisal opening (P <.01), with a greater increase in group 2, as well as a statistically significant difference (P <.05) in cephalometric stability, with group 2 being much more stable at long-term follow-up. All patients in group 1 grew back into skeletal and occlusal Class III relationships and required secondary intervention. Only 1 patient in group 2 required secondary surgery, involving maxillary surgery to correct postsurgical transverse maxillary relapse; the mandible was stable at long-term follow-up. The results of this study showed that patients with active condylar hyperplasia treated with high condylectomy, articular disc repositioning, and orthognathic surgery have stable, predictable outcomes compared with those treated with orthognathic surgery alone.     

高效液相色谱法同时测定人血清中普罗帕酮及其活性代谢物的浓度

A rapid, sensitive and simple high performance liquid chromatographicmethod for the simultaneous determination of propafenone (PPF) and its metabolites(5-hydroxypropafenone, 5-OHP; N-depropylpropafenone, NDP) in serum hasbeen developed. Separation of PPF, 5-OHP and NDP was achieved by reversed phasechromatography using a mobile phase consisting of 57% methanol and 43% 10 mmol/Lpotassium dibasic phosphate (pH 2.7)at a flow rate of 1.0 mi/rain on a 5μm ODS-C18column. The eluent was monitored at 254 nm. The method showed a good linearity. The recoveries of PPF, 5-OHP and NDP werefound to be 99.54±2. 13%, 100.02±3.66% and 100.48±3.10%, respectively. Precisionstudies for both within day and day-to-day at different concentrations provided RSDvalues of less than 5%. Some commonly used drugs can be determined in the same procedurewithout interference except phenytoin. This method is well adapted to the therapeuticmonitoring of PPF treated patients, as well as for pharmacokinetic studies.     

DL-111-1T对雌鼠肝脏及人羊膜细胞混合功能氧化酶活性的选择性诱导

以抗早孕药3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole(DL-111-1T)20 mg/(kg.d)预处理♀大鼠2 d,即可使动物肝微粒体。     

银杏叶提取物对溶血卵磷脂胆碱致血管内皮细胞损伤的保护作用

应用传代培养的小牛主动脉内皮细胞(BAEC)为实验模型,观察银杏叶提取物(EGb)对溶血卵磷脂胆碱(LPC)损伤BAEC及其分泌功能的影响。结果发现培养BAEC与LPC(2.5μg·mL^-1)孵育24h后,出现细胞皱缩成团,大多细胞脱落、甚至细胞解体。细胞内漏出LDH增加,脂质过氧化物(MDA)含量增高,SOD活性降低,而PAI活性增高。LPC与不同浓度EGb共孵育24h,大部分细胞排列规则,形态基本正常,LDH明显减少,MDA含量下降,SOD活性增高及PAI活性降低。结果表明LPC可致培养血管内皮细胞损伤,而EGb可对抗LPC所造成的血管内皮细胞损伤,可能通过清除氧自由基、抗脂质过氧化作用和提高EC产生抗氧化能力。     

Regulation of cyclin-dependent kinase 5 catalytic activity by phosphorylation

Cyclin-dependent kinase 5 (cdk5) is found in an active form only in neuronal cells. Activation by virtue of association with the cyclin-like neuronal proteins p35 (or its truncated form p25) and p39 is the only mechanism currently shown to regulate cdk5 catalytic activity. In addition to cyclin binding, other members of the cdk family require for maximal activation phosphorylation of a Ser/Thr residue (Thr(160) in the case of cdk-2) that is conserved in all cdks except cdk8. This site is phosphorylated by cdk-activating kinases, which, however, do not phosphorylate cdk5. To examine the possible existence of a phosphorylation-dependent regulatory mechanism in the case of cdk5, we have metabolically labeled PC12 cells with (32)P(i) and shown that the endogenous cdk5 is phosphorylated. Bacterially expressed cdk5 also can be phosphorylated by PC12 cell lysates. Phosphorylation of cdk5 by a PC12 cell lysate results in a significant increase in cdk5/p25 catalytic activity. Ser(159) in cdk5 is homologous to the regulatory Thr(160) in cdk2. A Ser(159)-to-Ala (S159A) cdk5 mutant did not show similar activation, which suggests that cdk5 is also regulated by phosphorylation at this site. Like other members of the cdk family, cdk5 catalytic activity is influenced by both p25 binding and phosphorylation. We show that the cdk5-activating kinase (cdk5AK) is distinct from the cdk-activating kinase (cyclin H/cdk7) that was reported previously to neither phosphorylate cdk5 nor affect its activity. We also show that casein kinase I, but not casein kinase II, can phosphorylate and activate cdk5 in vitro.     

Pituitary Apoplexy in a Patient with Acute Myeloid Leukemia and Thrombocytopenia

We describe a 72-year-old woman with a history of acute myeloid leukemia who developed pituitary apoplexy associated with thrombocytopenia secondary to chemotherapy. She presented with new onset severe headache, nausea, vomiting and blurred vision. Initial physical examination was unremarkable. CT scan of the head was initially negative. Upon admission for further work up, She developed a high-grade fever, hypotension and obtundation. Subsequent physical examination revealed bitemporal visual fields defects and decreased visual acuity. Repeat imaging of head revealed a hemorrhagic pituitary mass compressing the optic chiasm. Laboratory results were compatible with the diagnosis of pan-hypopituitary syndrome. She received high dose steroids and was transferred for transnasal sphenoidotomy decompression surgery. The visual defects improved postoperatively. A literature review of Pituitary apoplexy is presented. Pituitary apoplexy secondary to thrombocytopenia has never been reported.     

Structural changes in the Mn4Ca cluster and the mechanism of photosynthetic water splitting

Photosynthetic water oxidation, where water is oxidized to dioxygen, is a fundamental chemical reaction that sustains the biosphere. This reaction is catalyzed by a Mn₄Ca complex in the photosystem II (PS II) oxygen-evolving complex (OEC): a multiprotein assembly embedded in the thylakoid membranes of green plants, cyanobacteria, and algae. The mechanism of photosynthetic water oxidation by the Mn₄Ca cluster in photosystem II is the subject of much debate, although lacking structural characterization of the catalytic intermediates. Biosynthetically exchanged Ca/Sr-PS II preparations and x-ray spectroscopy, including extended x-ray absorption fine structure (EXAFS), allowed us to monitor Mn–Mn and Ca(Sr)–Mn distances in the four intermediate S states, S₀ through S₃, of the catalytic cycle that couples the one-electron photochemistry occurring at the PS II reaction center with the four-electron water-oxidation chemistry taking place at the Mn₄Ca(Sr) cluster. We have detected significant changes in the structure of the complex, especially in the Mn–Mn and Ca(Sr)–Mn distances, on the S₂-to-S₃ and S₃-to-S₀ transitions. These results implicate the involvement of at least one common bridging oxygen atom between the Mn–Mn and Mn–Ca(Sr) atoms in the O–O bond formation. Because PS II cannot advance beyond the S₂ state in preparations that lack Ca(Sr), these results show that Ca(Sr) is one of the critical components in the mechanism of the enzyme. The results also show that Ca is not just a spectator atom involved in providing a structural framework, but is actively involved in the mechanism of water oxidation and represents a rare example of a catalytically active Ca cofactor.