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61.
Replication checkpoint enforced by kinases Cds1 and Chk1 总被引:1,自引:0,他引:1
Cdc2, the kinase that induces mitosis, is regulated by checkpoints that couple mitosis to the completion of DNA replication and repair. The repair checkpoint kinase Chk1 regulates Cdc25, a phosphatase that activates Cdc2. Effectors of the replication checkpoint evoked by hydroxyurea (HU) are unknown. Treatment of fission yeast with HU stimulated the kinase Cds1, which appears to phosphorylate the kinase Wee1, an inhibitor of Cdc2. The protein kinase Cds1 was also required for a large HU-induced increase in the amount of Mik1, a second inhibitor of Cdc2. HU-induced arrest of cell division was abolished in cds1 chk1 cells. Thus, Cds1 and Chk1 appear to jointly enforce the replication checkpoint. 相似文献
62.
F Sánchez ME Martinez M Rubio J Carretero MN Moreno R Vázquez 《Canadian Metallurgical Quarterly》1998,253(2):75-78
Leiomyomas represent 2% of gastric tumors. Commonly, gastric leiomyomas are clinically silent. Most often they become clinically apparent due to bleeding from ulceration of the overlying gastric mucosa. Surgical extirpation of the tumor is the standard treatment. Gastric leiomyomectomy was done routinely through open laparotomy until availability of laparoscopic equipment and techniques. Recently, there have been a few published reports regarding laparoscopic or laparoscopic-assisted removal of smooth muscle gastric tumors. There is little data, however, describing or discussing a laparoscopic approach to gastric leiomyomas located on the posterior gastric wall. We describe two different laparoscopic approaches to posterior wall gastric leiomyomas that we used in two patients. The postoperative recovery of both patients was remarkably quick and uneventful. 相似文献
63.
MN Pollak 《Canadian Metallurgical Quarterly》1998,47(3):209-217
We studied the origin, length, external diameter, disposition, branching patterns and the perforators of short central artery in the circle of Willis in eighty fresh, unfixed cerebral hemispheres (40 brains). We also examined the relationship of the short central artery, the recurrent artery of Heubner, and M1 perforators to the anterior perforated substance, caudate and putamen. The short central artery arises at 5.2 +/- 3.36 mm from the origin of the anterior cerebral artery, hidden and overlapped by the internal carotid artery bifurcation. The recurrent artery of Heubner arises distally to the origin of the short central artery. Four main anatomical variations were found: 1. Presence of short central artery and recurrent artery of Heubner (37.5%). 2. Isolated presence of the short central artery (27.5%). 3. Isolated presence of the recurrent artery of Heubner (21.25%). 4. Absence of short central artery and recurrent artery of Heubner (13.75%). Two different branching patterns were observed: 1. 2-4 straight perforators from the short central artery, perforators from the recurrent artery of Heubner and lenticulostriate from the most medial portion of the M1, in 42 of 80 hemispheres (52.5%). 2. 8-10 perforators from only short central artery in 10 of 80 hemispheres (12.5%) with absent or hypoplastic recurrent artery of Heubner and lenticulostriates from M1 and M2. 相似文献
64.
65.
A fastidious, slowly growing, strictly aerobic, gram-negative bacterium was isolated from a culture of blood from a 25-year-old man with common variable immunodeficiency. The man had been admitted to hospital with febrile progressive cerebellar ataxia. The use of standard phenotypic schemes did not lead to identification, but sequence analysis demonstrated that the 16S rRNA gene of the isolate was most similar to those of the environmental bacteria Duganella zoogloeoides (formerly Zoogloea ramigera 115) and Telluria mixta. Further characterization of the bacterium by biochemical analysis, electron microscopy, G+C content estimation, and fatty acid analysis demonstrated significant differences between the bacterium and D. zoogloeoides and Telluria species; thus, we propose it as a new taxon with the name Massilia timonae gen. nov., sp. nov. 相似文献
66.
A 39-year-old woman presented with acute myocardial infarction due to spontaneous dissection of the left anterior descending artery. This was treated conservatively. She had been on combined oral contraceptive pills from the age of 22. Repeat coronary angiography 7 months later revealed spontaneous complete healing. 相似文献
67.
The purpose of this study is to evaluate the middle-term tonometric results of a new filtering procedure, the nonpenetrating deep sclerectomy with or without collagen device, in primary open-angle glaucoma. This technic aims to eliminate or minimize the complications of classical trabeculectomy. METHOD: This procedure was carried out by Koslov and colleagues. This is performed under a limbal-based conjunctival flap and a superfical scleral flap, the ablation of a deep scleral flap taking away the external wall of Schlemm's canal, only living in place the Descemet membrane. One must obtain a visible filtration across the opened Schlemm's canal and Descemet membrane. To improve the aqueous filtration, a cylindric collagen device, made from porcine scleral tissue, biocompatible, known for its high water content, is fixed in the deep scleral bed with a 10/0 nylon suture. This device provides a support for the elimination route of aqueous humor and acts like a sponge, carrying the liquid by capillary action. It is sterilized by irradiation. Full guarantee against viral contamination is provided. This procedure ends in one suture (10/0 nylon) of superficial scleral flap and conjunctival closing suture. When NPDS is performed without CD a sponge of 5FU is used and the superficial scleral flap is not sutured. RETROSPECTIVE STUDY: Our material included 111 patients, 148 eyes in CD group; 43 patients, 55 eyes in the group without CD. The average follow-up was 13.3 +/- 5.8 months in the CD group, 7.2 +/- 3.5 months in the group without CD. All patients presented a POAG without risk factors of bleb failure. RESULTS: The delta average IOP before the operation and at the end of the follow-up period was 7.2 +/- 6.3 mmHg in the CD group; 8.3 +/- 7.6 mmHg in the group without CD (no significant difference). The probability-success rate with the Kaplan-Meier method (IOP < or = 20 mmHg) was, in the CD group, at 18 months, 68% and 69% in the group without CD, without medical treatment. With monotherapy, the success rate was 85% in the CD group, 74% in the group without CD (p < or = 0.05). PROSPECTIVE STUDY: Afterwards, we have conducted a prospective study comparing two groups of patients with POAG without risk factors of bleb failure, operated with and without collagen device, without 5FU in the second group. Our material included 31 patients, 31 eyes, one eye for each patient, two surgeons; 17 eyes in the CD group, 14 eyes in the group without CD. The average age was 65.8 +/- 8.2 years in the first group; 64.1 +/- 10.3 in the second group. The average follow-up was 11 months in both groups. RESULTS: delta average IOP was 8.3 +/- 5.8 in the CD group; 12.3 +/- 6 in the group without CD (p < 0.05). The probability-success rate without treatment at 12 months: 58% in the first group, 90% in the second group (p < 0.05) and with monotherapy: 80% and 90% (N.S.). In both studies, in both groups, except microperforations, more frequent in the prospective group without CD, no complications of the trabeculectomy were observed. The mean change in visual acuity was inferior to 0.1 at the end of the follow-up. A postoperative rise in IOP can occur. It can be due to an internal obstruction (goniosynechiae or bad filtration). It can be treated with Nd-Yag laser. It can also be due to external obstruction, treated by 5FU injections into the bleb. The success of these procedures were similar in the whole group. CONCLUSION: Non penetrating deep sclerectomy can be considered as an excellent alternative to trabeculectomy in open and wide angles. It does not modify visual acuity. It carries away less complications than trabeculectomy and the use of antimitotic agents is safer. Collagen device does not seem, at middle-term, to improve tonometric results. 相似文献
68.
J Zhou LJ Quintero MN Helmus C Lee R Kafesjian 《Canadian Metallurgical Quarterly》1997,43(5):M470-M475
It has been postulated that, in theory, stentless bioprosthetic heart valves provide improved hemodynamics and durability over their stented counterparts. A number of glutaraldehyde modified porcine stentless valves are currently either on the market or in clinical trials. Polyepoxy compound as an alternative cross-linking reagent to glutaraldehyde for bioprostheses has been reported to mitigate calcification. The present study was to investigate the effect of the fixation methods on porcine aortic wall flexibility. Ring specimens were selected from three groups of porcine roots: fresh, low pressure glutaraldehyde fixed, and low pressure Denacol (polyepoxy compound) fixed. Pulled between two rods on a tensile tester, a ring specimen's load-deformation relationship was recorded and analyzed to numerically compute the tissue modulus at low strains. The results showed that the Young's moduli were 0.113 +/- 0.036, 0.494 +/- 0.113, and 1.320 +/- 0.292 MPa (mean +/- SD, n = 10) for the fresh, Denacol fixed, and glutaraldehyde fixed aortic walls, respectively. The Denacol fixed aortic wall was more flexible than the glutaraldehyde fixed one. It was also found that the Denacol fixed aortic wall maintained most of the natural residual strains, while the glutaraldehyde fixed aortic wall did not. 相似文献
69.
70.
NN Pribylova AI Tret''iakov AF Neronov MN Moskalev AI Kaminin NL Katyshev SI Portniagina 《Canadian Metallurgical Quarterly》1997,75(1):38-40
A correct access opening is the key to endodontics. An adequate anatomical access preparation maximizes cleaning, shaping, and obturation. The major objectives of access preparation are straight line access to the apical area, conservation of tooth structure, and unroofing of the pulp chamber. The safe-ended diamond bur technique provides an efficient and rapid means to obtain the objective of access preparation in posterior teeth. 相似文献