Turbulent stress measurements downstream of three bileaflet heart valve designs in pigs

Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage^®, CarboMedics© Orbis™ Universal and St. Jude Medical^® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred^® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m², and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m² and 15 N/m². In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m² for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes.     

真核表达人呼吸道合胞病毒F蛋白的纯化方法

目的 真核表达人呼吸道合胞病毒(human respiratory syncytial virus,SV)融合蛋白(fusion protein,),并完成蛋白纯化及纯度测定.方法 根据编码F蛋白的基因序列设计引物,CR方法扩增出3'端带His标签的F基因序列,克隆入pGEM-T-easy载体,经核酸序列分析后,进一步克隆到pcDNA3.1( )真核表达载体,限制性内切酶鉴定,用脂质体Lipofectamine2000转染COS-7细胞,2 h后再用Westem blot检测目的蛋白的表达.Ni柱亲和层析纯化COS-7细胞表达的F蛋白,高效毛细管电泳分析纯化后蛋白纯度.结果 核酸序列分析证实获得带His标签的RSV F基因序列,没有发生无义突变.转染COS-7细胞后,利用Western blot方法检测到F蛋白的特异性条带,纯度达99%以上.结论 初步建立了真核表达RSV F蛋白的纯化方法,为进一步优化RSV F蛋白制备条件及单克隆抗体及诊断试剂等研究奠定了基础.     

Genetic mapping of "Lubag" (X-linked dystonia-parkinsonism) in a Filipino kindred to the pericentromeric region of the X chromosome.

"Lubag" is an X-linked disorder causing dystonia and parkinsonism that has only been described in families from the Philippines, principally from the island of Panay. We have established linkage between the disease phenotype "lubag" and DNA markers which span the Xp11.22-Xq21.3 region by using a large Filipino family with 8 affected men in three generations. These DNA markers define an interval of about 20 centimorgans in the pericentromeric region of the X chromosome as the most likely site of the disease locus XDPD (X-linked dystonia-parkinsonism). XDPD has a maximum multipoint log likelihood ratio score (Zmax) of about 4.6 over the interval from Xq12 to Xq21.31 (DXS159-DXYS1X). The co-occurrence of dystonia and parkinsonism in lubag and in other known disorders suggests there may be a common pathogenetic mechanism. Identification of the genetic defect in this family may provide an important clue toward understanding the pathogenesis and pathophysiology of both dystonia and parkinsonism.     

Large-bowel carcinomas with different ploidy, related to secretory component, IgA, and CEA in epithelium and plasma.

Immunofluorescence staining for carcinoembryonic antigen (CEA), secretory component (SC), and epithelial IgA was evaluated semiquantitatively in 85 large-bowel carcinomas in relation to degree of tumour differentiation, Dukes'' stage, and plasma CEA level. The tumours were divided into a near-diploid (ND, 28) and an aneuploid group (AN, 57) by means of flow-cytometric DNA measurements. Expression of SC and IgA in neoplastic epithelium was positively related to differentiation in both groups. The AN tumours scored significantly higher for CEA than the ND ones, but the staining was apparently unrelated to differentiation or Dukes'' stage. CEA expression in the transitional mucosa adjacent to ND tumours was negatively correlated with tumour differentiation, whereas epithelial IgA and SC in this zone showed a substantially higher positive correlation with tumour differentiation, and a somewhat stronger negative correlation with Dukes'' stage in the ND than in the AN group. Plasma CEA levels were significantly related to Dukes'' stage, only in patients with AN tumours, and only in this group were positively correlated with estimates of total tumour CEA for Dukes'' stages A and B. For Dukes'' stages C and D (disseminated tumours), moreover, the plasma CEA levels were found to be significantly higher in the AN group. These findings indicate that the DNA profile of large-bowel carcinomas is related both to the way neoplastic cells influence the activity of the transitional mucosa and their capacity for expression and release of epithelial products. AN tumours thus seem to be more active as "secretors" of CEA than ND ones.     

Recovery of function in adjacent nerve roots after surgery for lumbar disc herniation: use of quantitative sensory testing in the exploration of different populations of nerve fibers

Results from experimental and clinical studies indicate that adjacent nerve roots may be affected in sciatica because of lumbar disc hemiation. This may be caused by proinflammatory mediators in the epidural space being transported into nerve roots at the same or neighboring lumbar segments. The aim of the present study was to investigate the recovery of function of sensory nerve fibers in the adjacent noncompressed nerve roots. Thirty-nine patients undergoing microdiscectomy for monoradiculopathy were investigated with quantitative sensory testing immediately before surgery, and at 6 weeks, 4 months, and 12 months after the operation. Twenty-one healthy volunteers were used as controls. The patients were classified as having a good or a poor result at the 1-year follow-up according to a clinical score. Significant improvement of function in the noncompressed nerve roots were only observed in the 31 patients with a good result. The improvement in small myelinated nerve fibers came within 12 months in the adjacent nerve roots in both the symptomatic as well as the asymptomatic leg. The improvement of function in small unmyelinated fibers also came within 12 months after surgery; however, significant improvement was only observed in the ipsilateral neighboring nerve root. The function in large myelinated fibers did not improve in any of the adjacent nerve roots during the observation period. The observed recovery of function in adjacent noncompressed nerve roots after successful surgical decompression in monoradiculopathy may be because of less production of proinflammatory mediators when the disc herniation is removed.     

激素治疗增加绝经后健康妇女尿失禁的发病率和严重程度

问题：在绝经后健康妇女中，激素治疗（hormone therapy，HT）对尿失禁（urinary incontinence，UI）的效果如何？     

Bladder and sexual dysfunction after mesorectal excision for rectal cancer

BACKGROUND: Urinary and sexual dysfunction are recognized complications of rectal excision for cancer. The aim of this study was to examine the frequency of such complications after mesorectal excision, shortly after this method was introduced. METHODS: Spontaneous flowmetry, residual volume of urine measurement and urodynamic examination, including cystometry and simultaneous detrusor pressure and urinary flow recording, was carried out before and 3 months after curative rectal excision. Urinary symptoms and sexual function were evaluated by means of questionnaires before and after operation. Each patient served as his or her own control. RESULTS: Forty-nine consecutive patients, 39 of whom had a total mesorectal excision (TME) and ten a partial mesorectal excision, were examined before surgery and 35 again after operation. In two patients, a weak detrusor was detected before operation. Two patients developed signs of bladder denervation after operation. Transitory moderate urinary incontinence appeared in four other women. Six of 24 men reported some reduction in erectile function and one became impotent. Two men reported retrograde ejaculation. All the complications were seen in the TME group. CONCLUSION: Mesorectal excision for rectal cancer resulted in a low frequency of serious bladder and sexual dysfunction.     

The capacity of particles to increase allergic sensitization is predicted by particle number and surface area, not by particle mass.

Particle exposure has traditionally been monitored as mass concentration of PM10 (particles with an aerodynamic diameter less than 10 microm), more recently also as PM2.5. The mass concentration is strongly influenced by the large particles. Therefore, particle mass is a poor measure for characterizing the amount of the small, possibly more biologically potent particles. We used polystyrene particles (PSP) ranging in diameter from 0.0588 to 11.14 microm, carbon black (CB), and diesel exhaust particles (DEP), to study the adjuvant effect of particles on the immune response to the allergen ovalbumin (OVA) after sc injection into the footpad of BALB/cA mice. At a given mass dose, the small particles (0.0588 and 0.202 microm PSP, CB, and DEP) increased the allergen-specific IgE serum levels to a substantially higher degree than the larger particles (1.053, 4.64, and 11.14 microm PSP). Further, in the draining lymph node during the primary response, the fine particles (0.202 microm) with OVA increased cell numbers, expression of surface markers (CD19, MHC class II, CD86, and CD23) and ex vivo production of IL-4 and IL-10, whereas the largest (11.14 microm) particles did not. Linear regression analyses indicated that the IgE response was not predicted by particle mass (R2 = 0.06), but was predicted by the total particle surface area (R2 = 0.64), number of particles (R2 = 0.62), and particle diameter (R2 = 0.58). In conclusion, we found that fine particles exerted stronger adjuvant effects on allergic responses than larger particles at equal mass doses. Consequently, the dose described as total particle surface area or particle number predicts the adjuvant effect of particles better than the currently used particle mass.