Acute vascular rejection is associated with systemic complement activation in a pig-to-primate kidney xenograft model

The introduction of h-DAF transgenic porcine organs into pre-clinical pig-to-primate discordant xenotransplantation has led to complete and reliable abrogation of hyperacute xenograft rejection (HAR). Despite additional heavy immunosuppression however, most xenografts are still lost due to acute vascular rejection (AVR), with current treatment protocols being of only limited value. In a life-supporting model of pig-to-primate kidney transplantation, unmodified (n=8) or h-DAF-transgenic (n=9) porcine kidneys were transplanted into cynomolgus monkeys under cyclophosphamide (CyP), cyclosporine and low-dose steroid immunosuppression. Longest recipient survival was 11 days in the control group and 68 days in the h-DAF transgenic group. Stable initial graft function with recipient survival >4 days was generated in eight animals (two controls and six transgenics). In these animals, plasma complement levels were analyzed during ongoing AVR. Compared with baseline levels, a two-fold increase in C3a levels and a four-fold increase in sC5b-9 levels were measured. In parallel to systemic complement activation, increased deposition of C3 and C5b-9 along with massive staining for recipient IgM immunoglobulins was detected in the xenografts on immunohistochemistry. We conclude that acute vascular xenograft rejection of porcine kidneys in cynomolgus monkeys is associated with classical pathway complement activation following binding of induced recipient anti-porcine antibodies. This complement activation can be observed despite membrane bound expression of human complement regulators in the porcine xenografts. Therefore, additional short-term fluid phase complement inhibition seems necessary for the future development of protocols designed for treatment of AVR in the pig-to-primate combination.

[Guidelines Clearing House Statement "Hypertension". Summary and recommendations for a rational hypertension guideline in Germany]

BACKGROUND

In order to promote quality of hypertension management in Germany, a national hypertension guidelines clearing project was initiated in 1999 by the German Guidelines Clearinghouse.

OBJECTIVES

To identify and review published German- and English language hypertension guidelines. To establish criteria for future guideline development and implementation. To familiarize stakeholders in Germany with state-of-the-art hypertension guidelines. To identify key topics for a future national evidence-based guideline.

METHODS

Search procedure, formal appraisal: Systematic search using literature databases and English-/German-language databases, published between 1990 and 1999. Abstract screening of the search results according to the inclusion criteria (n = 132 of a total of 548 hits). Systematic guideline evaluation using checklist with predefined criteria. APPRAISAL OF GUIDELINES' CONTENTS: Peer review of guidelines with the following inclusion criteria: hypertension--general, German and English language, published later than 1994, original or primary guideline or update, issued for nationwide use. Peer review was performed by a multidisciplinary focus group of EBM experts (primary and secondary care physicians, clinical pharmacologist, clinical epidemiologist). None of these was involved in hypertension guideline development during the review period. DOCUMENTATION OF CRITICAL APPRAISAL RESULTS: Systematic documentation of methodological appraisal and peer review results using a structured abstract form. The focus group wrote a final report (clearing report) including methodological abstracts for each guideline, essential topics for a future German hypertension guideline based on examples from the appraised guidelines, comments and recommendations for health care policy markers in Germany.

RESULTS

11 out of 132 guidelines were in accordance with the formal minimal standard with a wide range range within the following domains: "description of the development process", "declaration of authors' independence", "explicit link between recommendations and the supporting evidence", "management options", "tools for implementation". None of the guidelines identified all the key identified by the focus group, such as: (1) definition of hypertension--epidemiology--health care problems--intended guideline users/goals, (2) blood pressure measurement, (3) medical history and physical examination, (4) case-finding/screening, (5) indications for referral, (6) risk-stratification, (7) diagnostic procedures, (8) therapeutic goals/indications for therapy, (9) nonpharmacological measures, (10), pharmacotherapy, (11) follow-up/patient education/motivation/compliance, (12) comorbidity, hypertension in childhood/elderly, pregnancy, (13) primary prevention, (14) quality assurance/quality management, (15) dissemination/implementation, (16) open questions/challenges for the future.

SUMMARY POINTS

To improve the quality of hypertension management in Germany, the expert panel suggested to develop a national evidence-based guideline. This should follow internationally agreed criteria and procedures. The experts identified and reviewed 11 out of 132 hypertension, which might make useful contributions for a future German Hypertension guideline. The expert group identified 16 key topics for a national hypertension guideline.

Cationic ruthenium allenylidene complexes as catalysts for ring closing olefin metathesis

A series of well accessible cationic ruthenium allenylidene complexes of the general type [(eta6-arene)(R3P)RuCl(=C=CR'2)]+ X- is described which constitute a new class of pre-catalysts for ring closing olefin metathesis reactions (RCM) and provide an unprecedented example for the involvement of metal allenylidenes in catalysis. They effect the cyclization of various functionalized dienes and enynes with good to excellent yields and show a great tolerance towards an array of functional groups. Systematic variations of their basic structural motif have provided insights into the essential parameters responsible for catalytic activity which can be enhanced further by addition of Lewis or Bronsted acids, by irradiation with UV light, or by the adequate choice of the "non-coordinating" counterion X-. The latter turned out to play a particularly important role in determining the rate and selectivity of the reaction. A similarly pronounced influence is exerted by remote substituents on the allenylidene residue which indicates that this ligand (or a ligand derived thereof) may remain attached to the metal throughout the catalytic process. X-ray crystal structures of the catalytically active allenylidene complexes 3b.PF6 and 15.OTf as well as of the chelate complex 10 required for the preparation of the latter catalyst are reported.

Influence of cold ischemia time, pretransplant anti-porcine antibodies, and donor/recipient size matching on hyperacute graft rejection after discordant porcine to cynomolgus kidney transplantation

Organs transplanted between phylogenetically disparate species, such as from the pig into the primate, are subject to hyperacute rejection (HAR). This form of xenograft rejection is mediated by preformed natural antibodies and is believed to occur invariably in discordant xenografts thus leading to rapid destruction and complete thrombosis of the graft. Recent data, however, have shown that in the porcine to cynomolgus monkey setting, HAR is not inevitably seen after porcine kidney transplantation. The influence of preoperative antiporcine antibody levels in the recipient, cold ischemia time, and donor organ weight on the onset of HAR was investigated by using unmodified large white pigs (aged 3-12 weeks) as organ donors and adult cynomolgus monkeys (aged 1.5-3.5 years) as recipients. Porcine kidney xenotransplantation was performed in either a non-life-supporting model (n=7) or in a life-supporting model (n=8). In both models, no correlation was found between cold ischemia time and HAR. When preoperative anti-porcine antibody levels were investigated, a significant increase in incidence of HAR was observed in animals with elevated anti-porcine IgM (P<0.05) but not IgG levels (P=NS). Interestingly, although 5 of 12 grafts with an organ weight of less than 50 g underwent HAR, none of three grafts with a donor organ weight of more than 70 g showed signs of HAR. In addition, all three larger grafts showed intraoperative and postoperative urine production, although only in 1 (48 g) of the 12 grafts weighing less than 50 g primary graft function was observed. In one animal, a second porcine kidney (23 g) was successfully transplanted (without HAR) immediately after HAR and subsequent removal of a first porcine kidney (20 g). These results indicate that in the porcine to cynomolgus monkey setting anti-porcine IgM rather than IgG anti-porcine antibody levels seem to be of predominant importance for the induction of HAR. By increasing the donor organ size and weight the frequency of the onset of HAR can be at least reduced. This is most likely due to immunoabsorption of the recipients preformed antibodies in the porcine kidney without lethal damage for the graft.

[Goals and methods of clinical studies]

The validity of clinical patient-oriented research is always threatened by the influence of bias, confounding factors or random effects that might distort the results. However, the susceptibility to distortion varies between different study designs. The best protection against spurious relationships or distorted results are specific focused research questions and rigorous integration of sound study methodology during the design and performance phase.

[Evidence-based medicine--from evidence production to its implementation]

Evidence-based medicine (EBM) and evidence-based health care (EBHC) is one answer to the increasing need for quality and transparency in the care of individual patients as well as health care services. Using explicit and sound methodological criteria, EBM and EBHC question current management strategies for their effectiveness and usefulness to individual patients and patient groups. This approach therefore supports the implementation of rational patient-oriented care.

Investigation into the mechanism of bacterial adhesion to hydrogel-coated surfaces

As a model for hydrogel-coated biomaterials, self-assembled monolayers of polyoxyethylene (POE) derivatives on sheets of polymeric biomaterials were prepared. The POE derivatives consisted of hydrophilic chains with different lengths and a long-chain alkyl group that served as an anchor function. The coatings obtained were analyzed with XPS and contact angle measurements showing hydrophilic chains of different lengths extending away from the surface. Bacterial adhesion was measured with a clinically relevant Klebsiella pneumoniae type strain and measurements reproduced 12 times. Bacterial adhesion decreased markedly with increasing hydrophilic chain length. Based upon these findings a new model for bacterial adhesion to hydrogel-coated surfaces is suggested: steric repulsion effects that increase with increasing chain length of grafted hydrophilic chains play an important role in bacterial adhesion to hydrogel-coated surfaces.

The value of intraoperative laparoscopic examination of the contralateral inguinal ring during hernia repair in children

Approximately 40% of children with a clinical unilateral inguinal hernia display a patent processus vaginalis on the contralateral side; half of these children subsequently develop an inguinal hernia. The management of this problem is still controversial. Different strategies to identify patients who profit from an open contralateral exploration have been applied (diagnostic pneumoperitoneum, herniography, ultrasound). The purpose of this study was to evaluate the usefulness of intraoperative laparoscopy in a no-puncture technique through the opened hernia sack. In 75 children (age 6 months to 7 years) with clinical unilateral hernia laparoscopy (5-mm Laparoscope, 30 degrees and 70 degrees ), in cases of wide-open contralateral internal inguinal ring (Type III) an open surgical exploration was performed. Twelve patients (17%) fulfilled the laparoscopic criteria of a Type III ring. The diagnose was confirmed during open contralateral exploration. Seven children (8%) showed a patent but small processus vaginalis with a shallow internal ring. These patients were treated conservatively. In the follow-up period (median 6 months) one subsequent hernia developed. There was no technical failure, and no associated complications were seen. The median time for laparoscopy was 6 minutes. Intraoperative laparoscopy during unilateral hernia repair allows the identification of patients who profit from bilateral open surgery during the same operation with little additional operating time, and so far with no resulting complications. Application of this method may avoid a second hospitalization and operation as well as unnecessary routine bilateral open exploration. As an additional source of information through excellent visualization of the abdominal cavity, this method proved helpful to examine the incarcerated bowel after repositioning.

The unpredictability paradox: review of empirical comparisons of randomised and non-randomised clinical trials

OBJECTIVE

To summarise comparisons of randomised clinical trials and non-randomised clinical trials, trials with adequately concealed random allocation versus inadequately concealed random allocation, and high quality trials versus low quality trials where the effect of randomisation could not be separated from the effects of other methodological manoeuvres.

DESIGN

Systematic review.

SELECTION CRITERIA

Cohorts or meta-analyses of clinical trials that included an empirical assessment of the relation between randomisation and estimates of effect.

DATA SOURCES

Cochrane Review Methodology Database, Medline, SciSearch, bibliographies, hand searching of journals, personal communication with methodologists, and the reference lists of relevant articles.

MAIN OUTCOME MEASURES

Relation between randomisation and estimates of effect.

RESULTS

Eleven studies that compared randomised controlled trials with non-randomised controlled trials (eight for evaluations of the same intervention and three across different interventions), two studies that compared trials with adequately concealed random allocation and inadequately concealed random allocation, and five studies that assessed the relation between quality scores and estimates of treatment effects, were identified. Failure to use random allocation and concealment of allocation were associated with relative increases in estimates of effects of 150% or more, relative decreases of up to 90%, inversion of the estimated effect and, in some cases, no difference. On average, failure to use randomisation or adequate concealment of allocation resulted in larger estimates of effect due to a poorer prognosis in non-randomly selected control groups compared with randomly selected control groups.

CONCLUSIONS

Failure to use adequately concealed random allocation can distort the apparent effects of care in either direction, causing the effects to seem either larger or smaller than they really are. The size of these distortions can be as large as or larger than the size of the effects that are to be detected.

Association between the angiotensin-converting enzyme-insertion/deletion polymorphism and diabetic nephropathy: a methodologic appraisal and systematic review

Recent studies have implicated a variant of the angiotensin-converting enzyme gene (ACE), associated with increased activity of this enzyme, in the development and progression of diabetic nephropathy. This study provides a systematic review of all cross-sectional, case-control, and cohort studies in patients with insulin-dependent (IDDM) or non-insulin-dependent (NIDDM) diabetes mellitus of any race, examining the relationship between the ACE-insertion/deletion polymorphism and nephropathy. Nineteen studies in 21 populations published between 1994 and 1997 presenting data on 5336 patients were reviewed. Two investigators independently assessed the studies on methodologic quality, performance of study, and association between the ACE-insertion/deletion polymorphism and nephropathy. Separate analyses of the relationship between genotype and allele frequencies were performed for patients with IDDM and NIDDM by race, using Peto's odds ratio. In Caucasians with IDDM, pooling was not performed due to heterogeneity of the studies, but among the homogeneous studies, no association was detected. Likewise, no association was observed in Caucasian patients with NIDDM (odds ratio [OR], 1.10; 95% confidence interval [95% CI], 0.83 to 1.45). In Asian patients with NIDDM, the risk of nephropathy was increased in the presence of the DD or ID genotype (OR, 1.88; 95% CI, 1.42 to 2.85). Although this analysis fails to confirm an association between the ACE-insertion/deletion genotype and nephropathy in Caucasians with NIDDM or IDDM, a role for this genetic marker in Asian patients cannot be ruled out. However, due to methodologic limitations of individual studies, no definite conclusions can be drawn from this analysis. Clearly, more rigorous methodology needs to be applied in future studies.

[Risk of gastrectomy for stomach carcinoma in relation to reconstruction methods]

Between 1982 and 1996 we performed 452 total gastrectomies due to gastric cancer. 108 patients underwent a pouch reconstruction called Ulm pouch with preservation of the duodenal passage. In 251 patients, the reconstruction was made according to Hunt-Lawrence-Rodino and in 93 patients, a Roux-en-Y reconstruction without pouch was performed. In the Ulm pouch group, the rate of anastomotic leakage as well as the 30-day mortality was 0.8% and its relative risk was 2.6 times lower than in the other reconstruction groups (n = 452) and therefore, this type of reconstruction can be recommended for all curatively resected patients also with regard to morbidity and mortality.

[Sexual dysfunctions with antidepressive drugs--results of a physician survey]

In a survey throughout Switzerland 7.455 general practitioners and psychiatrists were mailed a questionnaire addressing topics in sexual medicine with regard to antidepressant medication, 940 completed questionnaires (response rate 12.5%) were evaluated. 77.6% of the responders agree that knowledge in sexual medicine is important or very important. Only one half of the physicians judge their competence in sexual medicine as fair or good. There are differences in sexual history taking between general practitioners and psychiatrists; the latter addressing more frequently sexual medicine related questions. Sexual dysfunction before and during therapy with antidepressants is observed less frequently than reported in other studies. Only half of the physicians counsel their patients when sexual dysfunction occur during therapy. Treatment strategies of antidepressant induced sexual side effects are rarely seen. The results emphasize the importance of knowledge and competence in sexual medicine for general practitioners and psychiatrists, both showing interest in continuing education on this topic.

Association between the angiotensinogen 235T-variant and essential hypertension in whites: a systematic review and methodological appraisal

Recently, an allelic variant of the angiotensinogen gene (AGT 235T) has been associated with increased risk of hypertension. However, this finding has not been confirmed by all investigators. A meta-analysis was performed to examine the association between the AGT 235T-allele and hypertension in whites and to identify potential reasons for the controversial results. All relevant articles published between 1992 and 1996 were identified through multiple sources. The studies were methodologically appraised, and the frequency of the AGT 235T-allele was extracted. The 235T-allele frequency was pooled using the common odds ratio (OR) estimator by Mantel-Haenszel. Homogeneity was assessed using the Breslow-Day test. Together these studies present data on 5493 patients. The AGT 235T-allele was significantly associated with hypertension (OR: 1.20; 95% [CI]: 1.11 to 1.29; P<.0001). This association increased in studies with positive family history (OR: 1.42; 95% CI: 1.25 to 1.61, P<.0001), recruitment of cases from referral centers (OR: 1.39; 95% CI: 1.20 to 1.62, P<.0001), and more severe hypertension (OR: 1.34; 95% CI: 1.22 to 1.47, P<.0001). However, the presence of methodological problems in all studies gives rise to serious concerns regarding bias and confounding. Despite a statistically significant, albeit weak, association between the AGT 235T variant and hypertension that has been confirmed through sensitivity analysis, this finding has to be interpreted with caution, as the methodological weaknesses of the individual studies are likely to have biased the outcome of the meta-analysis. Clearly, more rigorous methods need to be applied in association studies on the genetics of human hypertension.

[Value of pylorus preserving partial duodenopancreatectomy in ductal pancreatic carcinoma]

In a study compiling the data in a prospective manner, the value of the pylorus-preserving duodenopancreatectomy (PPPD) compared to partial duodenopancreatectomy (PD) in patients suffering from ductal pancreatic carcinoma was assessed. Postoperative morbidity, mortality and overall prognosis were analysed. From May 1990 to April 1995 130 patients entered the study; 61 underwent PD, 69 patients had PPPD. The patients were regularly followed up every 6 months and the median follow-up period for all patients was 36 months. PPPD in patients with ductal pancreatic head carcinoma without infiltration of the duodenum is the technically simpler and faster operation method with significantly less blood loss. Moreover, PPPD did not lead to increased postoperative complications. The median survival rate of patients in the PD group was 10.8 months, in the PPPD group 21 months. This significant difference derives from the fact that the tumor stages were unevenly distributed. Regarding the most common stage (stage III according to UICC) the median survival times were almost identical (PD group 10.1 months, PPPD group 11.2 months). The PPPD operation seems to be a sufficiently radical procedure which does not worsen the prognosis of the disease.

[Differences between evidence based-medicine and best conventional medicine]

The practical application of rational concepts will be possible in the health care system if two conditions will be met. The legal framework has to fit these goals and new strategies are to establish. The new strategies will be needed to identify from the huge amount of data "evidence" which will support the medical progress. Evidence-Based Medicine (EBM) offers these strategies. Modifications of our conventional procedures are necessary to establish EBM: the conditions of clinical actions, the definitions of goals of medical training, the rational of clinical decisions and the continued medical education.

[Postoperative and post-traumatic acute cholecystitis. Value of ultrasound diagnosis]

An often unrecognized but potentially fatal complication, mostly seen in posttraumatic patients under intensive care, is reactive acute cholecystitis. On account of the high specificity of ultrasound diagnosis in the biliary system we decided to examine the ultrasound criteria for early detection of posttraumatic cholecystitis. Ultrasound of the abdomen was performed prospectively, seven times on different days, in each of 40 artificially respirated patients under intensive care conditions over a period of 12 months. The results show that artificial respiration, parenteral feeding and previous trauma can lead to tardive (28/40) wall-thickening or to a three-layered wall of the gallbladder (9/40). In 22.5% of patients (9/40) we found the sonographic signs of acute cholecystitis. In correlation with the clinical signs, cholecystectomy was indicated in only two patients. The preoperative ultrasonographic findings and clinical signs of 23 patients with the diagnosis of acute reactive cholecystitis were analysed retrospectively. We found good correlation between sonographic and clinical signs of acute cholecystitis in 21 of these 23 patients. Our study shows that the morphological correlate of a thickened three-layered gallbladder wall can occur in the context of systemic alterations, even if there is no underlying cholecystitis. The diagnosis of acute reactive cholecystitis and the indication for cholecystectomy should be based on the synopsis of pathologic and clinical findings.

[Postoperative analgesia after endoscopic abdominal operations. A randomized double-blind study of perioperative effectiveness of metamizole]

In comparison to conventional operating technique endoscopic surgery reveals numerous advantages, particular rapid mobilisation and earlier discharge from observation. For a effective utilization of these advantages, it is desirable to have a efficient postoperative analgesic scheme, which can be continued into the period after discharge from hospital. In a randomised, prospective double-blind study we investigated the analgesic efficacy of dipyrone in 40 patients, scheduled for endoscopic abdominal surgery (mainly endoscopic cholecystectomy). Patients received before induction of anesthesia either dipyrone (1 g/100 ml NaCl i.v.) or placebo (100 ml NaCl i.v.). These infusions were repeated 6 h and 12 h after first application. After surgery all patients were allowed to self-administer buprenorphine intravenously from a PCA-pump (Bolus 30 micrograms, lockout 5 min in the recovery room, 30 min on the ward). Every hour for the first 6 h and after 24 h, cumulated doses of buprenorphine, pain scores (0-10), pulse, blood pressure and side effects were recorded. Dipyrone-treated patients had significantly less pain immediately after surgery and used a significantly lower cumulated dose of buprenorphine (-67%; 90 micrograms vs. 270 micrograms buprenorphine) in the first 24 h after surgery.