Electromyographic activity while performing the anti-G straining maneuver during high sustained acceleration.

The purpose of this study was to measure the muscle activity during performance of the anti-G straining maneuver (AGSM) at high sustained acceleration stress (+Gz = head-to-foot inertial loading). Ten males were exposed on three separation occasions to a rapid onset rate of 6 + Gz. Subjects wore standard United States Air Force (USAF) anti-G trousers and performed the AGSM until perceived fatigue or until achieving light loss criteria. During each exposure, surface electromyography (EMG) was recorded from the erector spinae, external oblique, bicep femoris, vastus lateralis, and lateral gastrocnemius muscles. The normalized root-mean squares (RMS) and mean power frequency (MPF) for each muscle were calculated and tested for significant differences with an analysis of variance (ANOVA) procedure. The results of this study showed that mean amplitude decreased during the AGSM (35.40%) while MPF showed no significant change. The EMG amplitude of lower extremity muscles decreased (61.45%) while the amplitude of trunk muscles decreased slightly (3.45%). These results indicate that during the performance of the AGSM, motor unit recruitment in lower extremity muscles decrease without evidence of fatigue.     

Aluminium speciation in cerebrospinal fluid of acutely aluminium-intoxicated dialysis patients before and after desferrioxamine treatment; a step in the understanding of the element's neurotoxicity

Background: The association between aluminium and dialysis encephalopathy and deterioration of the neurological state during desferrioxamine treatment of dialysis patients is well established. At present little is known about the speciation and the mechanisms underlying the element's neurotoxicity. Methods. Aluminium speciation was performed in cerebrospinal fluid samples of acutely aluminium-intoxicated dialysis patients using a recently developed high-performance liquid chromatographic/electro-thermal atomic absorption spectrometric hybrid method. Results: Baseline cerebrospinal fluid aluminium levels of samples taken shortly after the intoxication were low but elevated (5.0±2.0 &mgr;g/l, n=3) as compared to subjects with normal renal function (<1 &mgr;g/l). In contrast to the situation noted in serum and to the iron speciation in cerebrospinal fluid, aluminium was not bound to transferrin but appeared as two distinct compounds, the main fraction eluting at the elution volume of aluminium citrate/silicate. The second compound was not identified. Forty-four hours after desferrioxamine administration the cerebrospinal fluid aluminium levels had increased up to a concentration of 10.3±2.5 &mgr;g/l (n=3). This was accompanied by a change in the speciation profile with aluminium appearing at the elution volume of aluminoxamine. Conclusion: Our findings may contribute to a better understanding of the neurotoxic effects of aluminium and its desferrioxamine chelate in dialysis patients.     

Xenogeneic bone marrow transplantation: II. Porcine-specific growth factors enhance porcine bone marrow engraftment in an in vitro primate microenvironment

Abstract: Establishment of mixed bone marrow chimerism in pig-to-primate transplantation, as a means of inducing specific immune tolerance, will require that both immune and nonimmune barriers be overcome. As a preliminary step in evaluating nonimmune barriers in this system, we have developed an in vitro model of engraftment in which long-term culture of porcine bone marrow-derived hematopoietic cells is supported on preformed primate bone marrow stromal layers. In the absence of cytokine supplementation, primate stromal cells were unable to support long-term porcine hematopoiesis in these cultures. Supplementation with porcine Steel Factor was required for long-term maintenance of hematopoietic progenitor cell content and total hematopoietic activity. Addition of porcine IL-3, in combination with porcine Steel Factor, increased long-term progenitor cell content and hematopoietic activity on primate stroma to levels comparable to that obtained in cultures on porcine stroma. The combination of porcine GM-CSF and Steel Factor increased progenitor cell content and hematopoietic activity early in the cultures, but had little effect in long-term cultures. The Steel Factor and IL-3 combination was species-specific in its action in these cultures, as the corresponding human cytokines were unable to effectively support long-term porcine hematopoiesis. Likewise, the combination of porcine cytokines had only minimal effects on long-term bone marrow culture of primate CD34+ cells I on primate stroma.     

Laparoscopic cholecystectomy and time-course changes in renal function

Background: Recently, the retraction method has been used to reduce intraabdominal pressure (IAP) during laparoscopic surgery. The purpose of this study was to determine the serial changes in renal function during laparoscopic cholecystectomy (LC) using the retraction method. Methods: Urine output, effective renal plasma flow (ERPF), and glomerular filtration rate (GFR) were measured serially in seven patients who underwent LC with 12 mmHg pneumoperitoneum (High-IAP group) and five who underwent LC using the retraction method with 4 mmHg pneumoperitoneum (Low-IAP group). Results: Urine output, ERPF, and GFR were decreased during pneumoperitoneum in the High-IAP group, whereas no significant changes in any of these parameters were observed in the Low-IAP group. Conclusions: Our findings demonstrate that reduction of IAP to 4 mmHg using the retraction method prevents the transient renal dysfunction caused by prolonged 12 mmHg pneumoperitoneum during LC, suggesting that the retraction method reduces the risk of perioperative renal dysfunction during laparoscopic surgery. Received: 26 March 1996/Accepted: 27 July 1996     

结肠腺瘤与腺癌p53,c—erbB2蛋白及CEA的表达和意义

应用免疫组化法检测１５例正常结肠粘膜，４０例结肠瘤及４０例结肠癌组织的ｐ５３，ｃ－ｅｒｂＢ２和ＣＥＡ的表达。结果发现：结肠癌患者ｐ５３，ｃ－ｅｒｂＢ２及ＣＥＡ的阳性表达率均显著高于腺瘤（Ｐ〈０．０１）。ｐ５３阳性表达在不典型增生腺瘤患者中，重度显著高于轻度病例（Ｐ〈０．０１）；在结肠腺癌患者中低分化显著高于高分化病例（Ｐ〈０．０５）；ＣＥＡ的新型单克隆抗体ｃｏｌ－１对结肠癌的敏感性和特异性均高，阳     

Content of HSP70 in rats with hereditary stress-induced arterial hypertension

Sensitivity of normotensive Wistar rats and NISAG rats (with hereditary arterial hypertension) to heat stress is compared at the organism and cell levels. High temperature sensitivity of NISAG rats correlates with a low content of the main heat shock protein HSP70. This relationship can serve as a biochemical marker of predisposition to arterial hypertension. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 171–173, August, 1997