The <Emphasis Type="Italic">Arg</Emphasis>194<Emphasis Type="Italic">Trp</Emphasis> polymorphism in DNA repair gene XRCC1 and the risk for sporadic late-onset Alzheimer's disease

Abstract Alzheimer's disease (AD) is defined pathologically by the presence of β-amyloid plaques, neurofibrillary tangles and extensive neuronal loss. Evidence indicates that increased DNA damage may contribute to neuronal loss in AD. Recently, it has been shown that in AD neurons have a reduced capacity for some types of DNA repair. Polymorphisms in DNA repair genes may be associated with differences in repair efficiency of DNA damage. Variants of several DNA repair genes, including the base excision repair gene XRCC1, have been described previously. We hypothesised that Arg194Trp polymorphism of XRCC1 gene may contribute to genetic susceptibility for AD. In order to test this hypothesis, we investigated Arg194Trp polymorphism at the XRCC1 gene in the DNA samples of 98 patients with AD and 95 healthy subjects. The frequency of the Trp allele was more pronounced among cases (11.2%) compared with controls (5.8%). On combining the homozygous and heterozygous variants of each codon, the variants seemed to be at twofold risk of AD, although the risk estimates were not statistically significant (OR=1.95, 95% CI 0.88–4.34, p=0.09). In addition, the 194Trp allele revealed a borderline significance (OR=2.05, 95% CI 0.96–4.37, p=0.056). According to our results, it may be speculated that the polymorphic variants of XRCC1 codon 194 have a role in the development of AD.     

p21对缺血-再灌注损伤后肾小管上皮细胞演变的影响

目的 探讨p21对缺血-再灌注损伤（IRI）后肾小管上皮细胞演变的影响。方法 选择低龄（2个月龄）和高龄（12个月龄）p21（＋／＋）和p21（-／-）鼠，建立左肾IRI模型。于IRI后0、1、3、7d及1、3、6个月光镜下观察肾小管组织学变化，采用免疫组化法检测肾小管上皮细胞增殖细胞核抗原（PCNA）表达，组织化学染色观察肾小管上皮细胞衰老相关β-半乳糖苷酶（SA-β-gal）活力，末端脱氧核糖转移酶介导的生物素化脱氧尿嘧啶缺刻标记技术（TUNEL）检测肾小管上皮细胞凋亡。结果 IRI后0d，肾小管以坏死为主，高龄鼠比低龄鼠严重、p21（-／-）鼠比p21（＋／＋）鼠严重（P均〈0．05）。肾小管上皮细胞凋亡在IRI 1d后出现，7d达高峰，且高龄鼠比低龄鼠明显、p21（-／-）鼠比p21（＋／＋）鼠明显（P均d0．05）。低龄鼠IRI后1个月出现SA—β-gal染色阳性的肾小管上皮细胞，而对侧肾此时未见衰老细胞，3和6个月时衰老的肾小管上皮细胞显著增多，且p21（＋／＋）鼠比p21（-／-）鼠明显（P〈0．05）；p21（＋／＋）高龄鼠IRI后0d双肾即可见大量的SA-β-gal染色阳性肾小管上皮细胞，且较p21（-／-）鼠显著增多（P〈O．05），但1d后，p21（＋／＋）和p21（-／-）鼠IRI肾衰老细胞均明显减少（P均〈0．05），1个月后又呈进行性增加，且p21（＋／＋）鼠始终比p21（-／-）鼠严重。高龄和低龄p21（＋／＋）鼠PCNA阳性染色细胞出现的几率差异无显著性（P〉0．05），但低龄鼠细胞增殖能力要强于高龄鼠；而p21（-／-）鼠的细胞增殖能力明显强于p21（＋／＋）鼠，低龄鼠更为显著（P均〈0．05）。对高龄鼠IRI后1d细胞衰老和凋亡进行相关分析显示，二者呈显著负相关Cp21（＋／＋）鼠：r=-0．82，P〈0．001,p21（-／-）鼠：r=-0．76，P〈0．0013。结论 ①IRI可促进正常肾小管上皮细胞衰老的进程；②已经进入衰老状态的肾小管上皮细胞在遭受IRI刺激后，更易走向死亡[坏死和（或）凋亡]；③p21在IRI所致肾小管上皮细胞演变过程中发挥重要的调控作用。     

Spiral-shaped Metallic Implant in the Treatment of Achilles Tendon Ruptures: An Experimental Study on the Achilles Tendon of Sheep

There are 2 main factors contributing to the strength of tendon repair: the tensile strength of the material used in repair and the tendon-holding capacity of the suture configuration. In the current study, we aimed to find a technique with high repair strength by increasing both the tensile strength of the material and the tendon-holding capacity of the configuration. We developed metal implants (models 1 and 2) made from stainless-steel wire with 2 different spiral-shaped configurations. We measured tendon-holding capacities of these alternative implants biomechanically and compared them with frequently used suture techniques, the Bunnell and locking loop, which were achieved with 5 Ticron sutures. Sixty-four sheep Achilles' tendons were used in the study as 16 tendons in each group. Model 2 was more resistant to deformation under loading when compared with model 1. The results demonstrated that model 2 was superior to model 1 and both suture techniques. This study could be accepted as a step for reaching a strong tendon repair technique. It should be emphasized that the technique needs to be improved technically to make it convenient for clinical use.     

Unusual presentation of myocardial ischemia after arterial switch operation.

Ischemic changes and acute or subacute cardiac failure after arterial switch operation generally results from imperfect transfer of coronary arteries to the neoaorta. Peroperative and early postoperative myocardial ischemia is the main cause of death in these patients. We present an unusual cause of myocardial ischemia and cardiac failure after arterial switch: a congenital coronary artery fistula between the circumflex artery and the right ventricle. The symptoms imitate coronary translocation failure. In differential diagnosis of the coronary perfusion problems encountered after the arterial switch operation, coronary artery fistula should not be forgotten, although it is rare.     

The role of surgery in intraabdominal Burkitt's lymphoma in children.

The role of surgery in intraabdominal Burkitt's lymphoma remains controversial and different opinions are present in the literature. In our institution, forty patients (30 boys and 10 girls) with intraabdominal Burkitt's lymphoma with ages ranging from 3 to 12 years have been treated and followed from 1989 through 2000. In ten cases, the patients underwent surgery because of their acute abdominal diseases (intestinal obstruction in 5, intussusception in 3, intestinal perforation in one, and acute appendicitis in one). The remaining thirty patients were referred to our clinic because of their abdominal masses, pain, anorexia and fatigue. Twelve children had localized tumors and total resection could be performed. There was one death in this group due to central nervous system involvement during chemotherapy. In the remaining 28 children, extensive intraabdominal diseases were detected. In four of them, debulking procedures were performed, while in 24 children only biopsies could be made; 8 of them underwent a second-look operation. In the debulking procedures group, two children were lost (50 %) due to tumorlysis and acute renal failure. In the biopsy group, there were six deaths (25 %). All patients received chemotherapy after operative recovery. In conclusion, our results suggest that when the tumor is localized, total resection results in a good outcome. However, in the presence of extensive intraabdominal diseases instead of resection, the operation should be limited to biopsy only.     

Synthesis, Raman, FT-IR, NMR spectroscopic characterization, antimicrobial activity, cytotoxicity and DNA binding of new mixed aza-oxo-thia macrocyclic compounds

Series of new mixed aza-oxo-thia macrocyclic ligands 1,9(2,6)-ditriazina-2,8,10,16-tetraaza-3,7,11,15-tetraoxo-5,13-dithia-cyclohexadecaphan-1⁴,9⁴-diphenyl (L₁); 1,10(2,6)-ditri azina-2,9,11,18-tetraaza-3,8,12,17-tetraoxo-5,6,14,15-tetrathia-cyclooctadecaphan-1⁴,10⁴-diphenyl (L₂); 1,11(2,6)-ditriazina-2,10,12,20-tetraaza-3,9,13,19-tetraoxo-6,16-dithia-cyclocosa-phan-1⁴,11⁴-diphenyl (L₃); 1,12(2,6)-ditriazina-2,11,13,22-tetraaza-3,10,14,21-tetraoxo-6,7,17,18-tetrathia-cyclodocosaphan-1⁴,12⁴-diphenyl (L₄) were synthesised. The structural features of the compounds have been studied by elemental analyses, Mass, FT-Raman, FT-IR, ¹H and ¹³C NMR spectroscopy. The antimicrobial activities of the ligands were evaluated using disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against several bacteria and yeast cultures. The obtained results from both methods were assessed in side-by-side comparison with commercial antibacterial and antifungal agents. In most cases, the compounds show strong antifungal activity in the comparison tests. Cytotoxic activities of the ligands against two different human cancer cell lines, stomach (23132/87) and lung (A549) were determined by MTT assay. DNA fragmentation assay tested cell lines were used to analyze the DNA ladder formation which is a characteristic of apoptotic cell death. The binding of the ligands with calf thymus DNA (CT-DNA) has also been investigated by absorption spectroscopy.     

Does gastric adenocarcinoma develop after the treatment of gastric lymphoma?

Two adult patients with the diagnosis of gastric lymphoma who developed adenocarcinoma of the stomach 8 years after the treatment are presented. Both patients were treated by subtotal gastrectomy followed by irradiation of 4,000–4,500 cGy to the epigastric region and six courses of chemotherapy (vincristine, cyclophosphamide, prednisolone). In our review of the literature, 16 cases of gastric adenocarcinoma following the treatment of gastric lymphoma were found and listed with details. The factors influencing the development of this secondary carcinoma, mainly those treatment related are discussed. The possible role of both radiotherapy and chemotherapy in shortening the latent period for the development of stump carcinoma is emphasized. © 1993 Wiley-Liss, Inc.     

Treatment of hypertensive urgencies with oral nifedipine, nicardipine, and captopril

Sixty-five patients with uncomplicated hypertensive urgencies were treated in the emergency and cardiology departments with 20 mg nifedipine, 20 mg nicardipine, or 25 mg captopril in a randomized study. The study population consisted of 65 patients ranging in age from forty-one to seventy-one. Blood pressure and heart rate were assessed for six hours after intake of the antihypertensive agents. Within sixty minutes nifedipine reduced blood pressure by an average of 74.7 mmHg for the systolic and 35.4 mmHg for the diastolic. Average heart rate increased significantly by 11.6 beats/min at within thirty minutes. Nicardipine and captopril produced equivalent falls in systolic (-81.6 and -79.4 mmHg) and diastolic (-37.3 and -33 mmHg) blood pressure respectively, but did not increase heart rate significantly. The antihypertensive effect of each drug was maintained until six hours after medication. In conclusion, nifedipine, nicardipine, and captopril show similar efficacy in the treatment of hypertensive urgencies. The authors believe that these drugs can be used as first-line therapy in the treatment of hypertensive urgencies safely and effectively.     

A fluid level in an acute extradural haematoma

We report a fluid level in an acute extradural haematoma developing after placement of a ventriculoperitoneal shunt for hydrocephalus. This fluid level was thought to be due to a mixture of blood and cerebrospinal fluid.