Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation

Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs.     

Treatment of a juvenile patient with a maxillary all-ceramic resin-bonded fixed partial denture: a case report.

Treatment of juvenile patients with a missing maxillary incisor is difficult, because an implant cannot be placed until growth is completed. The other minimally invasive alternatives are also problematic: Removable dentures are rarely accepted by juvenile patients, and the conventional resin-bonded fixed partial denture often provides a poor esthetic result because the metal retainer causes the abutment teeth to lose their natural translucency and to become grayish. Moreover, the alveolar ridge defect makes it easy to identify the prosthesis in the pontic area. The present case report describes the prosthetic treatment of a juvenile patient who had lost a maxillary incisor to trauma. To avoid the disadvantages of conventional therapies, subepithelial connective tissue was grafted to reshape the alveolar ridge. The space was closed with an all-ceramic resin-bonded fixed partial denture.     

Sirolimus allows renal recovery in lung and heart transplant recipients with chronic renal impairment.

BACKGROUND: Until recently, there has been no practical alternative to the use of calcineurin inhibitors (CIs) as primary immunosuppressants in lung transplantation (LTx) and heart transplantation (HTx). Sirolimus (SRL) is a novel powerful immunosuppressant without renal toxicity, a common post-transplant problem associated with CI therapy. METHODS: SRL was used in 20 LTx and 5 HTx recipients >90 days post-transplant, where serious renal impairment was limiting CI dosing. Patients started on 2 to 5 mg/day orally at a median of 1,185 days post-transplant. Dosage adjustments were made according to trough levels, toxicity and perceived efficacy. With SRL initiation, 48% ceased CI therapy and the remainder decreased their dose substantively. RESULTS: After 30 days, 4 of 5 dialyzed patients ceased dialysis and 15 of 20 patients with an elevated serum creatinine (Cr) (mean Cr 0.29 mmol/liter) improved their Cr. The direction of change in Cr at 30 days predicted longer term Cr. The starting Cr did not predict the 30-day or long-term value. There were two bouts of acute and one bout of chronic rejection. There were 35 infectious complications in 16 patients and 24 episodes of potential SRL-related toxicity in 17 patients. These events generally responded to dose reduction or temporary cessation and were level-related. Fifteen recipients presently remain on the drug. None of the 7 deaths could be directly related to toxicity. CONCLUSION: SRL is a useful alternative immunosuppressant, allowing significant CI withdrawal in transplant recipients with renal impairment. Whether the resulting improvement in Cr can be maintained in the long term probably depends on the balance between the extent of acute and chronic renal damage.     

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.      

力学在食管胃腔内弹力环扎吻合术的应用

本文探讨食管胃腔内弹力环扎吻合术的力学机理。这是一种不用任何缝合材料或吻合器进行胃食管吻合的新技术,我们已成功应用于临床。取临床所用的乳胶管按该材料多向异性特征、实验条件以及弹力环数目分为8组,每组3个样品进行各种体外力学试验。通过应力—应变(拉力—伸长)关系曲线和定伸长松驰试验确定它的力学特性是一种粘弹性材料。根据实验所得的应力换算为弹力环对食管和胃组织所施加的最佳压力(压强)是4.23±0.23Kg/cm~2,这样才能保证这一种新颖的吻合术可达到简便、安全、可靠的目的。     

离子交换处理对褐煤加氢液化的影响及其机理

考察了褐煤离子交换处理前后的加氢液化性能,探讨了不同形态铁催化剂和不同溶剂对褐煤加氢液化的影响。发现在液化反应条件下,离子交换煤中的(RCOO)_3Fe分解为Fe_3O_4,后者在有较高供氢性能的溶剂中和有硫存在的条件下进一步转化为Fe_(1-x)S,其催化活性高于Fe_3O_4。此外,在液化残渣的Mossbauer谱中发现有γ-Fe,它可能是由Fe_(1-x)S还原而成,其催化活性比Fe_(1-x)S更高。     

自拟白术桃花汤治疗习惯性便秘临床观察

目的　观察白术桃花汤治疗习惯性便秘的疗效。方法　自拟白术桃花汤 (白术 30g ,桃花 12g ,生地黄 30g ,枳实 10g) ,每日服 1剂 ,7d为 1个疗程。对照组服用果导片作对比观察。结果　白术桃花汤治疗习惯性便秘 117例 ,治愈 10 6例 ,好转 4例 ,总有效率 94 .0 2 %;果导片治疗 6 6例 ,治愈18例 ,好转 30例 ,总有效率 72 .73%。两组总有效率比较 ,经统计学处理P <0 0 1,差异有非常显著性意义。结论　白术桃花汤功能为补气除湿 ,增液行气 ,通调大便 ,治疗习惯性便秘疗效满意。     

Early and mid–term results of the Shelhigh stentless bioprosthesis in patients with active infective endocarditis

Summary Aims This study investigated the early and mid–term results following valve replacement with the new Shelhigh^? stentless bioprosthesis made entirely of biological material in patients with active infective endocarditis (AIE). Material and methods Between 02/2000 and 12/2004, 164 patients (n = 122 men, mean age 59, 18–85 years) received implantation of an AIE Shelhigh^? stentless bioprosthesis in the aortic, mitral, tricuspid or pulmonary position. A total of 119 patients (72.6%) had native AIE and 45 (27.4%) prosthetic AIE. A large proportion of the patients reached the operating room in a condition of cardiac decompensation: 37 (22.6%) patients were intubated, 40 (24.4%) had protracted septic shock and 41 (25.0%) required intensive catecholamine treatment. Surgery was regarded as urgent in 94 patients (57.4%) and was performed as an emergency procedure in 70 (42.6%). The mean follow–up time is 1.5 ± 0.11 years (range, 5 months to 5.2 years). Echocardiographic follow–up examinations were performed early postoperatively and after 12 months. Results In terms of the operative indication, we found a highly significant difference in the survival rate between patients who were operated on urgently vs in an emergency. In patients who died within 30 days, the main cause of death was septic multiorgan failure (67.6%). Only three patients required reoperation due to reinfection of the Shelhigh^? bioprostheses; this represents a reinfection rate of 1.8% in relation to the whole cohort. The postoperative echocardiographic examinations showed the Shelhigh^? valves to have very good hemodynamics without relevant pressure gradients. Conclusion Our experience in the use of Shelhigh^? bioprostheses in patients with native and prosthetic endocarditis show the early and mid–term results, in particular the low reinfection rate and the good hemodynamics, to be comparable with the results achieved using homografts. Since these prostheses are readily available and their implantation straightforward, they are increasingly being used in patients with endocarditis. These promising results need to verified in the long term. This paper was presented at a lecture held at the 71^st annual meeting of the German Society for Cardiology, Mannheim, 31. March—2. April 2005. Disclosure Form: The following study discloses my relationship with any corporate sponsor that might relate in some way to the subject presented.     

新疆家畜蠕形蚤病病原研究

本文详细介绍了在新疆发现的花蠕形蚤、叶氏蠕形蚤、北山羊蠕形蚤、羊长喙蚤和狍长喙蚤的形态学特点、地理分布和某些生物学特性。