The surgical risk of pancreas transplantation in the cyclosporine era: an overview

BACKGROUND: Pancreas transplants are still associated with the highest surgical complication rate of all routinely performed solid organ transplants. To date, the impact of serious surgical complications in the cyclosporine era on perioperative patient morbidity, graft and patient survival, and hospital costs has not been analyzed in detail. STUDY DESIGN: We retrospectively studied surgical complications after 445 consecutive pancreas transplants (45% simultaneous pancreas-kidney [SPK], 24% pancreas after kidney [PAK], and 31% pancreas transplant alone [PTA]). Of these, 80% were primary transplants, 20% were retransplants. Cadaver donors were used in 92%, living related donors in 8%. To develop guidelines for their prevention and management, we studied the impact of significant surgical complications (intra-abdominal infections, vascular graft thrombosis, and anastomotic leak) requiring relaparotomy on graft and patient survival. RESULTS: Relaparotomy was required after 32% of all pancreas transplants (SPK: 36%, PAK: 25%, PTA: 16% [p = 0.04]). Perioperative mortality was 9%. Graft and patient survival rates were significantly lower for recipients with (versus without) relaparotomy. The most common procedures were drainage of intra-abdominal abscess with graft necrosectomy (50% of all relaparotomies) and transplant pancreatectomy (34%). The most common causes of relaparotomy were intra-abdominal infection, vascular graft thrombosis, and anastomotic leak. Intra-abdominal infection occurred in 20% (SPK: 18%, PAK: 24%, PTA: 20% [p = NS]). The rate was significantly higher for living related donor (42%) versus cadaver donor (18%) recipients and for those with enteric-drained (39%) versus bladder-drained (18%) transplants. Graft and patient survival rates were significantly lower for recipients with (versus without) intra-abdominal infection. Outcome was better after bacterial (versus fungal) infections. For SPK recipients, those not on dialysis before the transplant had significantly higher graft survival than those on dialysis. Vascular graft thrombosis occurred in 12% of all recipients. The rate was significantly higher for PAK (21%) than for PTA (10%) and SPK (9%) recipients. It was significantly lower for recipients of grafts with donor iliac Y-graft reconstruction (versus all other types of arterial reconstruction) and with right-sided (versus left-sided) graft placement. Of note, patient survival was not different for recipients with versus without vascular graft thrombosis. The incidence of anastomotic or duodenal stump leaks was 10%; of these recipients, 70% required relaparotomy. Patient and graft survival rates were no different for recipients with versus without leaks. CONCLUSIONS: Serious surgical complications occurred in 35% of pancreas recipients and had a significant impact on patient and graft survival. Based on multivariate risk factor analyses, we recommend the following: donors over 45 years and those dying of cerebrocardiovascular disease should not be used; recipients over 45 years and those with a history of cardiac disease should be considered for a kidney transplant alone (KTA); surgical technique for graft procurement, preparation, and implantation should be meticulous; right-sided implantation and arterial Y-graft reconstruction should be performed when possible, since they had the highest success rates; when complications require relaparotomy, the focus must switch from graft salvage to life preservation; and the threshold for pancreatectomy should be low. Diagnosis should be timely, and treatment and relaparotomy expeditious. These cornerstones of success should help decrease the risk of surgical complications and mortality after pancreas transplants.     

The complex pathology of trinucleotide repeats

The expansion of trinucleotide repeat sequences has now been shown to be the underlying cause of at least ten human disorders. Unifying features among these diseases include the unstable behavior of the triplet repeat during germline transmission when the length of the repeat exceeds a critical value. However, the trinucleotide repeat disorders can be divided into two distinct groups. Type I disorders involve the expansion of CAG repeats, which encode an expanded polyglutamine, inserted into the open-reading frame of a gene that is usually quite broadly expressed. Recently, mouse models for type I disorders have been developed and the basis of pathology is under study, both in these models and through biochemical and cell biological approaches. The type II disorders involve repeat expansions in noncoding regions of genes. The mechanisms by which these repeat expansions lead to pathology may be quite diverse.     

PROTEIN-PHYTATE INTERACTIONS IN SOYBEANS. II. MECHANISM OF PROTEIN-PHYTATE BINDING AS AFFECTED BY CALCIUM

Phytate and bovine serum albumin were used in a model system to investigate the mechanism of their binding. Ultrafiltration studies using response surface design showed the association of protein and phytic acid to be highly pH dependent. Under acid conditions, the protein formed an insoluble complex with phytic acid. At pH 3.0, a binding constant of 2.3 times 10⁵ was obtained and it was calculated that there are 78 binding sites of the total 93 basic amino acid residues potentially available. This low pH complex was not disrupted at high temperatures but the presence of calcium ions caused dissolution of the precipitate. Calcium produced different effects at higher pH (> 6). Soluble protein-calcium-phytic acid complexes were formed which were less stable to heat and dissociated above pH 10 at high ionic strength. Since this interaction occurred only in the presence of calcium, a salt linkage is implicated in which divalent cations simultaneously bind to the protein and phytic acid in the form of a soluble complex. It is proposed that either the addition of divalent cations at low pH or sequestering agents at high pH would best effect the removal of phytate from soy products by ultrafiltration.     

The removal of arsenic from （ground）-water by adsorbent loaded in polymeric microspheres

Arsenic is a natural tasteless and odourless element,existing in the earth’s crust at average levels of between two and five thousands micrograms per liter (parts per million) . Arsenic is highly toxic to humans, who are exposed to it primarily from air,food and water. The occurrence of arsenic in groundwater is due to geological composition of soil. High concentrations of arsenic in water are the result of dissolution or desorption of ferric oxides and the oxidation of mineral arsenopyrites. Arsenic in drinking water has an important impact on the human health,especially in the less developed countries. Different methods exist to remove arsenic from aquatic media,and one of them is by adsorption. In this work,the adsorption of both As(III) and As(V) by means of novel microspheres has been investigated. In particular,TiO2 has been embedded into polymeric microspheres PES (PolyEtherSulphone) and PEEK-WC (PolyEtherEther-Ketone) . The main advantages of this encapsulation adsorption material are: no loss of adsorbents into the water stream,easy to be used and scaled-up.     

THEORETICAL ANALYSIS OF THE DIFFUSION PROCESS INSIDE PROLATE SPHEROIDAL SOLIDS

ABSTRACT

A numerical solution of the diffusion equation to describe solute transport inside ellipsoids, assuming a constant difiusion coefficient and a corrective boundary condition, is presented. The difiusion equation in a prolate spheroidal coordinate system was used for a hidimensional case. The finite volume method was employed to discretize the basic equation, utilizing a uniform grid size. The equation was solved irteratively using the Gauss-Seidel method. The effect of Biot number and the aspect ratio of the body on diffusion rate and concentration during the process is presented. Plots are presented for Biot numbers from 0.05 to infinity and aspect ratios of 1.1, 2.0 and 5.0. To investigate the effect of the aspect ratio, different results changing the aspect ratio for Bi= 1.0 are shown. The results show that the model is consistent and it may be used to solve other cases such as those that include cylinder and sphere geometry, and/ or those with variable diffusion coefficients with small modifications.     

ANTENNAL AND BEHAVIORAL RESPONSES OF GRAPEVINE MOTH <Emphasis Type="Italic">Lobesia botrana</Emphasis> FEMALES TO VOLATILES FROM GRAPEVINE

Grapevine moth Lobesia botrana is the economically most important insect of grapevine Vitis vinifera in Europe. Flower buds, flowers, and green berries of Chardonnay grapevine are known to attract L. botrana for oviposition. The volatile compounds collected from these phenological stages were studied by gas chromatography—mass spectrometry, and the antennal response of L. botrana females to these headspace collections was recorded by gas chromatography—electroantennography. The compounds found in all phenological stages, which consistently elicited a strong antennal response, were pentadecane, nonanal, and -farnesene. In a wind tunnel, gravid L. botrana females flew upwind to green grapes, as well as to headspace collections from these berries released by a piezoelectric sprayer release device. However, no females landed at the source of headspace volatiles, possibly due to inappropriate concentrations or biased ratios of compounds in the headspace extracts.     

氨合成塔选型

介绍了在合成氨改扩建工程中，选择氨合成塔时应着重考虑的工艺参数和结构设计，并在实际工作中得到验证。     

Micro-Analysis of ＂Sulfate Salt Weathering Distress on Concrete＂：Ⅱ.Concrete

运用环境扫描电镜、能谱仪和X射线衍射等微观分析手段研究了稳定环境中,半浸泡混凝土试件在硫酸钠和硫酸镁溶液中的劣化破坏特征,以及混凝土碳化对＂混凝土硫酸盐结晶破坏＂的影响。结果表明：粗骨料界面过渡区生成的大量钙矾石和石膏等晶体是引起混凝土试件劣化的原因;在碳化混凝土内发现了硫酸钠结晶破坏现象。     

卤代烃的制备工艺

介绍了一种液相法生产分子式为ＣＡＲ＾１Ｒ＾２ＣＢＲ＾３Ｒ＾４（此外的Ｒ＾１,Ｒ＾２、Ｒ＾３和Ｒ＾４指代意义如专项说明中所定义）的卤代烷加成物的工艺,是将相应的卤代烷烃（ＡＢ）与相应的烃（ＣＲ＾１Ｒ＾２＝ＣＲ＾３Ｒ＾３）在催化的存在下于溶剂中进行反应,所用的催化剂组成：（１）至少有一种含一价铜;（２）至少有一种为离子促进剂,选自卤代铵、吡啶或卤代吡啶及（ＭＱ４）Ｙ型的四价盐（Ｍ是元素周期表中ＶＡ族元素,如Ｎ、Ｐ、Ａｓ、Ｓｂ或Ｂｉ,Ｑ为Ｃ１－Ｃ１８烷烃、Ｙ为氯、溴或碘）。还介绍了用上述工艺制得的加成产物与ＨＦ反应制备一些氢氟烃的工艺,该工艺是在二晴或环化碳酸酯溶剂中进行,使反应混合物分成两相。