Vertebroplasty in the treatment of spinal diseases

The results of surgical treatment by vertebroplasty are analyzed in 28 patients with different spinal diseases. A procedure for percutaneous vertebroplasty with polymethyl methacarylate is presented. This miniinvasive method has been shown to be highly effective in treating vertebral hemangiomas, osteoporotic compression fractures, and vertebral metastases and in strengthening the anterior vertebral column as compared with anterior spondylosis in open surgical operations.     

Model Studies of the Mechanisms of Tuning of Visual Cortex Neurons to Incomplete Cross-Shaped Figures

Numerical simulation modeling of the receptive fields of visual cortex neurons able to detect cross-shaped figures with masked central or peripheral areas was performed. Receptive field models of two types were considered: those with antagonistic and cooperative interactions between the center and the periphery. Model neurons with receptive fields with reciprocal (antagonistic) interactions produced greater responses to peripheral or central crosses than to complete crosses. Studies using the model showed that the basis of this type of tuning could be provided by a disinhibition mechanism: blockade of the inhibitory zones in the center or periphery of the receptive field by activation of a lateral disinhibitory zone. A model with cooperative interactions between the center and periphery of the receptive field was also studied, in which responses to complete crosses were summed from the responses to the peripheral and central parts. Tuning of these model receptive fields was comparable to the sensitivity of real visual cortex neurons to the shape, size, and orientation of figures. The properties of model receptive fields (configuration, localization, and weightings of the various zones) allowing simulation of the properties of cat visual cortex field 17 neurons sensitive to the orientation and configuration of incomplete cross-shaped figures were identified.     

双链断裂修复蛋白hKu70缺陷细胞株的建立及其生物学特性

目的 建立并鉴定DNA双链断裂(DSB)修复蛋白hKu70缺陷细胞株,并观察该缺陷细胞的某些生物学效应,用于AKu70基因功能及职业有害因素对DNA双链断裂修复影响的研究。方法 用构建的AKu70基因反义RNA绿色荧光蛋白真核表达载体(pEGFP—CI—K)转染人胚肺成纤维细胞(HLF),用蛋白兔疫印迹法鉴定转染细胞中AKu70基因的表达水平。同时观察转染细胞生长形态,绘制生长曲线,软琼脂培养法鉴定恶性程度。结果 pEGFP—CI—K载体在转染细胞内可较稳定表达,hKu70蛋白缺陷细胞株AKu70基因的蛋白表达水平下降了42％,转染后hKu70蛋白缺陷细胞生长形态、生长速度无明显变化,软琼脂培养未见细胞集落。结论 成功建立和鉴定了hKu70蛋白缺陷细胞株,该缺陷不足以单独引起可观察的某些生物学效应。     

Effect of alcohol on conduction of afferent impulsation from the area of the sinus node of the heart to structures of the central nervous system

Acute experiments in cats, using the induced potentials technique, showed intraperitoneal 30% alcohol administration (1.5-2 ml per 1 kg body weight) as well as direct application of 2 or 3 ml of similarly concentrated alcohol solution to the sinus node area (SNA) to block afferent impulse conduction from the SNA to central nervous structures, such as cerebral cortex, reticular formation of the midbrain, peri-aqueduct gray matter. The fact that the induced potentials generated within the cerebral cortex and subcortical structures in response to SNA stimulation showed a pattern of change that was similar to the one associated with alcohol administered intraperitoneally or applied directly to SNA has suggested that alcohol may block the cardiac afferent flow directly at the level of SNA structures.     

Magnetohydrodynamic thermochemotherapy of malignant tumors with nanopreparations with magnetic resonance monitoring

Intravenous administration of dextran-ferrite sol was used to amplify T₂-weighed echo gradient (500/15) scanning MR images with visualization of the invasion margins of tumor cells into healthy tissues, along with macro-and micrometastases, in animals with lymphocytic leukemia and Ehrlich and Lewis carcinomas. Magnetohydrodynamic thermochemotherapy (MTCT) using a cyclophosphamide-containing magnetic fluid (saturation magnetization (M_s) 8.6 kA/m, pH 7.4, ζ + 13 mV) at 46°C for 30 min in an alternating magnetic field (0.88 MHz, 7.2 kA/m, 0.15 kW) with aspiration of necrotic material (ANM) produced regression of P388 tumors of volume ∼110 mm³ in BDF1 mice prior to metastasis by 40%, with an increase in lifetime (ILT) of 310%; in tumors of volume ∼330 mm³ after metastasis and MTCT-ANM with cyclophosphamide pretreatment, ILT was 220%. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 42, No. 4, pp. 3–10, April, 2008.     

The sensitivity and specificity of the immediate-spin crossmatch

The immediate-spin (IS) crossmatch is used to detect ABO incompatibility between donor red cells (RBCs) and the serum of the intended recipient. However, this test may be positive in the absence of ABO incompatibility (false positive) or it may be negative when ABO incompatibility exists (false negative). During a 25-month study, the rates of both false-positive and false-negative IS crossmatch results were evaluated, and the sensitivity and specificity of the IS crossmatch were determined. During the study period, 53,656 IS crossmatches were performed for patients without significant RBC antibodies. Fifty-five patients had positive IS crossmatches, and no false-negative reactions were found. In tests of 55 patients with positive IS crossmatches, 77 false-positive and 5 true-positive reactions were noted. The causes of the false-positive reactions were rouleaux (36 patients), cold-reactive antibodies (8 patients), a combination of rouleaux and cold-reactive antibodies (2 patients), fibrin clot (1 patient), and undetermined (3 patients). The sensitivity and specificity of the IS crossmatch were 100 and 99.86 percent, respectively. Laboratory personnel should be aware that the IS crossmatch may have false-positive or false-negative results, and they should develop written protocols to distinguish quickly between true-positive and false-positive reactions.     

When should antibody screening tests be done for recently transfused patients?

The American Association of Blood Banks (AABB) requires that blood samples used for pretransfusion testing of recently transfused (or pregnant) patients must be obtained within 3 days of scheduled transfusions. This requirement, which became effective in July 1988, amended Standard G2.000 of the AABB, which previously required that pretransfusion testing must be done on blood samples obtained within 2 days of scheduled transfusions. The present study was designed to estimate the risk associated with adopting the amended version of Standard G2.000. Sixty patients who developed significant unexpected alloantibodies after transfusion were studied retrospectively. Thirteen of the 60 patients were found to have newly detectable antibodies within 83 hours of a sample reported to be negative for the new antibody. Had the amended version of Standard G2.000 been in effect, the detection of some of these antibodies might have been delayed up to 24 hours. It was estimated that the implementation of the new AABB requirement at the authors' institution could potentially place about 1 in 3000 transfused patients at risk for an acute or delayed hemolytic transfusion reaction.