Prevalence and prognostic significance of renal artery calcification in patients with diabetes and proteinuria

BACKGROUND AND OBJECTIVES

Vascular calcification is common and severe in chronic kidney disease. Because the consequences of calcification may differ by vascular beds, we sought to test the hypothesis that patients who have diabetes with proteinuria and have significant renal artery calcification (RAC) have a higher risk for progression to ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using electron-beam computed tomography, RAC was computed as the sum of Agatston scores at each of the two renal ostia and renal arteries. Time-to-event analysis was conducted to compare the risk in individuals with or without significant RAC (total score >10).

RESULTS

Of 172 patients with type 2 diabetes and overt proteinuria studied (estimated GFR 56 ± 25 ml/min per 1.73 m(2)), significant RAC was present in 31%. In 33 ± 21 months, 41 progressed to ESRD and 65 reached a composite outcome (ESRD or death). Serum phosphorus was a significant predictor of progression to ESRD but was replaced by the significant RAC in multivariate models that included the latter. Individuals with significant RAC had a higher risk for reaching the composite outcome. In contrast, there was no association between coronary artery calcification scores and progression to ESRD.

CONCLUSIONS

Significant RAC was an independent predictor of progression to ESRD as well as reaching the composite outcome. Understanding the pathogenesis of RAC would allow determination of whether this risk is potentially modifiable.

Mexican-American admixture mapping analyses for diabetic nephropathy in type 2 diabetes mellitus

Diabetic nephropathy is a classic complex trait, whose development in a given individual reflects contributions from multiple genes and whose expression is modulated by environmental factors. Numerous genetic strategies have been used to identify common disease risk loci and genes, including candidate gene analyses, linkage analysis, transmission disequilibrium testing (a family based association test to identify linkage between a genetic marker and a biological trait or disease), and admixture mapping (also referred to as mapping by admixture linkage disequilibrium). Choosing the best genetic strategy to identify susceptibility genes in a disease is dependent on knowing whether the disorder is monogenic (the result of one gene), oligogenic (the result of a few genes), or polygenic (the result of many genes). The likelihood of finding risk loci for a disease with a putative genetic contribution is in part owing to the disease recurrence risk ratio (the risk of expressing the disease phenotype in siblings of the proband divided by the risk observed in the general population), the genotypic risk ratio (the risk of expressing the phenotype if the gene is present divided by the risk if the gene is not present), the number of susceptibility genes, how the susceptibility genes interact, how much of the disease risk is contributed by environmental factors, and the disease penetrance (the likelihood that the phenotype will be expressed if the gene is present).

Successful mycophenolate mofetil therapy in nine patients with idiopathic retroperitoneal fibrosis

OBJECTIVE

To assess the therapeutic benefit of mycophenolate mofetil (MMF) in retroperitoneal fibrosis (RF).

METHODS

MMF 2 g/day and prednisone 1 mg/kg were initiated in nine patients with radiological (9/9) and histological verification (2/9) of idiopathic RF. Out of nine patients, seven needed bilateral ureteral stenting due to extensive hydronephrosis.

RESULTS

All patients experienced regression of radiological extension. Out of seven patients, five were free of ureteral catheters after a mean of 5.6 months and two remained on stenting due to secondary stenosis. Within 6 months mean creatinine and CRP fell from 2.5 to 1.2 mg/dl and from 4.0 to 1.4 mg/dl, respectively. MMF was discontinued after a mean of 27 months. Prednisone was tapered to zero after a mean of 7 months. Side-effects were urinary tract infections in 7/9 patients and impaired glucose tolerance in 3/9. No recurrence occurred after withdrawal of glucocorticoids and MMF in 7/9 patients after a mean overall follow-up of 55 months (range 12-120).

CONCLUSIONS

Treatment with MMF and glucocorticoids was successful in inducing partial or complete and lasting remission in RF. The results suggest the use of MMF as additional immunosuppressive option.

[Effects of active and passive smoking on the health of children and adolescents]

Tobacco abuse is especially a public health problem among children and teenagers in Germany. While the proportion of adolescents smoking regularly was 18% in 1997, this has increased to more than 30% in 2001. The high impact of peer groups in young people aggravates the development of smoking habits. Furthermore, an addiction to nicotine develops mainly before the age of 20 (80% of all adults smokers have started as teenagers). Early and continued damage to health will result in long-term sequelae due to immaturity of the organs. Fortunately, the proportion of smoking adolescents has decreased in the last few years. Besides the well known effects of active smoking, children are especially endangered by environmental tobacco smoke (ETS). Exposure to cigarette smoke during pregnancy is directly correlated to premature rupture of the membranes, premature birth, delayed foetal development, and reduced lung function. Children are suffering from impairments of their health not only due to ETS exposure in utero but also after birth (e. g., diseases of upper and lower airways, delayed physical and mental development). Therefore, the prevention of active and passive smoking must be intensified and should consider the special situation of children and adolescents.

Poor correlation between coronary artery calcification and obstructive coronary artery disease in an end-stage renal disease patient

Vascular calcification is highly prevalent and often severe in patients with chronic kidney disease. Arterial calcification in patients with chronic kidney disease can result from the deposition of mineral along the intimal layer of arteries in conjunction with atheromatous plaques or from calcium deposition in the medial wall of arteries, also known as Monckeberg's sclerosis. Whether coronary artery calcium scores as measured by electron beam computed tomography correlate with occlusive atherosclerotic disease in the dialysis population is uncertain. Here we report a case of an asymptomatic patient with diabetes mellitus and end-stage renal disease undergoing maintenance hemodialysis, who was found to have extremely elevated coronary artery calcium scores on electron beam computed tomography, but varied degrees of atherosclerotic plaque in her coronary arteries on coronary angiography. This suggests that in addition to the calcification anticipated in a remodeled intima, a proportion of the calcification is also likely to be in the arterial media. Thus, this case demonstrates that even an extremely high coronary calcium score may not be a satisfactory surrogate marker for obstructive atherosclerosis in elderly diabetic dialysis patients.

Hypovitaminosis D in chronic kidney disease

BACKGROUND AND OBJECTIVES

Recent studies show high prevalence of suboptimal 25-hydroxyvitamin D levels in chronic kidney disease patients. This study sought to test the hypothesis that the prevalence of 25-hydroxyvitamin D deficiency is significantly higher in chronic kidney disease patients and, in diabetic nephropathy, low serum 25-hydroxyvitamin D is associated with abnormal serum parathyroid hormone, bone mineral density, and coronary artery calcification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Study A used data from the Third National Health and Nutrition Examination Survey. Study B was a post hoc analysis of an observational study of coronary artery calcification in non-dialysis-dependent diabetic nephropathy.

RESULTS

In study A, the adjusted odds for 25-hydroxyvitamin D deficiency were 32% higher in chronic kidney disease patients. This higher prevalence of 25-hydroxyvitamin D deficiency, however, could not be explained by differences in total vitamin D intakes. The consequences of suboptimal 25-hydroxyvitamin D levels were analyzed in 146 patients with diabetic nephropathy. The significant, inverse relationship between serum 25-hydroxyvitamin D and parathyroid hormone levels was attenuated to a nonsignificant level on multivariate adjustment. There was a significant, inverse relationship between bone mineral density and coronary artery calcification scores; neither was independently associated with serum 25-hydroxyvitamin D. The serum 25-hydroxyvitamin D levels declined modestly in 72 patients studied after 12.4 +/- 0.4 mo.

CONCLUSIONS

25-Hydroxyvitamin D deficiency is more common in chronic kidney disease, but this higher prevalence is unlikely to be a result of lower vitamin D intakes. The consequences of suboptimal 25-hydroxyvitamin D levels remain to be definitively elucidated.

Racial differences in mortality among those with CKD

Compared with white individuals, black individuals have a significantly higher risk for death in the general population but seem to have a survival advantage in the ESRD population. Data on the relationship of race to survival in early stages of chronic kidney disease (CKD) are inconsistent. This study evaluated racial differences in mortality among the adult participants of the Third National Health and Nutrition Examination Survey, a population-based survey of community-dwelling individuals. CKD was defined either by an estimated GFR < 60 ml/min per 1.73 m2 or by the presence of albuminuria, and this status was determined for 14,611 individuals, 2892 of whom were found to have CKD. Adjusting for age,gender, and race, risk for all-cause mortality among individuals with CKD was more than double that of individuals with normal renal function. In the subgroup with CKD, adjusting for age and gender,black individuals had a significantly higher risk for death, and this risk was modified by age;specifically, black individuals who were younger than 65 yr were 78% more likely to die than white individuals, whereas no significant differences in mortality were observed among individuals who were > or = 65 yr of age. Further adjustment for cardiovascular risk factors and CKD stage did not materially change the results, but the hazard ratios were significantly attenuated after adjustment for socioeconomic factors. In conclusion, these data demonstrate racial/ethnic disparities in mortality among individuals with CKD. This higher risk for death in early stages of CKD may explain the apparent survival advantage observed among black individuals who live long enough to reach stage 5 CKD.

Analysis of 94 patients with advanced biliary tract cancer

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Background: Cholangiocarcinoma or gallbladder cancer are often diagnosed at an advanced stage with limited treatment options. Methods: Between 1994 and 2004, 94 patients (pts) (47 male, 47 female) with advanced biliary tract cancer were treated at the Department of Oncology and Hematology, University Hospital Hamburg-Eppendorf. Clinical and histopathological characteristics, response to chemotherapy, and survival were investigated in a retrospective analysis. Median age was 59 years (range 30–80) and median Karnofsky performance status was 90%. Predominant histologic type was adenocarcinoma (94.7%). Primary tumor sites were extrahepatic bile duct (29.9%), gallbladder (28.7%), intrahepatic bile duct (10.6%), ampulla of Vater (2.1%), not specified (28.7%). Predominant localizations of metastases were liver (73 pts (77.7%)), lymph nodes (49 pts (52.1%)) and the peritoneum (14 pts (14.9%)). 33 pts (35.1%) underwent surgery of the primary tumor at time of diagnosis. Results: 72 of 94 pts (76.6%) received a first-line chemotherapy, all together 10 different chemotherapy regimens were used. The median number of cycles was 2.5 (range 1 - 12). A single agent chemotherapy with gemcitabine was the most often adminstered regimen (23 pts (31.9%)), followed by carboplatin and etoposide plus whole body hyperthermia (12 pts (16.7%)) and 5- fluorouracil and folic acid (10 pts (13.9%)). The overall response rate was 8.3% (95% CI 3.1 - 17.3) (34.7% SD, 47.2% PD, 9.7% not evaluable). Second-line chemotherapy was given in 27 patients, which induced no tumor response, but a stable disease rate of 22.2%. Median time to follow- up was 44.8 months. Survival was calculated for all 94 pts since time of diagnosis. Median overall survival was 12.2 months and median progression-free survival 9.2 months. The median overall survival time for the 72 pts who were treated with chemotherapy was 14.0 months, and for the 22 pts who did not receive chemotherapy 10.7 months (p=0.2). Conclusions: Our analysis showed a poor prognosis for patients with advanced biliary tract cancer. Response rate to chemotherapy was low. Therefore, well tolerated cytotoxic agents should be used and new treatment strategies (including molecular targeted therapy) should be further investigated.

No significant financial relationships to disclose.

Laser Doppler flowmetry detection of endothelial dysfunction in end-stage renal disease patients: correlation with cardiovascular risk

Prediction of cardiovascular (CV) complications represents the Achilles' heel of end-stage renal disease. Surrogate markers of endothelial dysfunction have been advocated as predictors of CV risk in this cohort of patients. We have recently adapted a noninvasive laser Doppler flowmetry (LDF) functional testing of endothelium-dependent microvascular reactivity and demonstrated that end-stage renal disease patients are characterized by profound alterations in thermal hyperemic responsiveness. We hypothesized that such functional assessment of the cutaneous microcirculation may offer a valid, noninvasive test of the severity of endothelial dysfunction and CV risk. To test this hypothesis, we performed a cross-sectional study, in which we compared LDF measurements to conventional risk factors, and performed a pilot longitudinal study. LDF studies were performed in 70 patients and 33 controls. Framingham and Cardiorisk scores were near equivalent for low-risk patients, but more divergent as risk increased. C reactive protein (CRP) levels and LDF parameters (amplitude of thermal hyperemia (TH), area under the curve of TH) showed significant abnormality in high-risk vs low-risk patients calculated using either Framingham or Cardiorisk scores. Patients who had abnormal LDF parameters showed increased CV mortality, however, had similar risk assessments (Framingham, Cardiorisk, CRP, and homocysteine) to those with unimpaired LDF tracings. In conclusion, LDF parameters of microvascular reactivity offer a sensitive characterization of endothelial dysfunction, which may improve CV risk assessment through incorporation into the Framingham or Cardiorisk algorithm.

The effects of solvents on embryonic stem cell differentiation

Dimethyl sulfoxide (DMSO) and ethanol are common organic solvents used for dissolving lipophilic substances for in vitro testing. However, DMSO is known to induce differentiation in embryonic stem (ES) and embryonic teratocarcinoma (EC) cells. In order to clarify if solvents like DMSO and ethanol have an influence on in vitro developmental toxicity test systems, the presented study has evaluated their effects on differentiation by using different test systems. ES and EC cells were transfected with a construct containing the mTert promoter combined with the green fluorescent protein gene (GFP). A down-regulation of mTert, a marker for undifferentiated cells, results in a lower expression of GFP, which could be measured by flow cytometry. Taking the specific characteristics of ES and EC cells into account this effect could be a hint for the interaction of DMSO with embryonic development. Additionally, the effects of the solvents ethanol and DMSO on Oct-4 expression, another marker for undifferentiated cells, were measured in wild-type ES cells. Both selected molecular markers demonstrated an induction of differentiation after exposure to DMSO; in wild-type ES cells at a concentration of 0.125% and in transgenic EC cells at a concentration of 0.25% DMSO. All other differences from controls, including those which attained a level of statistical significance, were minor or not dosage related in degree, or were not consistent over time and are, therefore, considered to be of little toxicological importance. In addition, a cytotoxicity test demonstrated that the solvents affected the employed molecular markers in non-cytotoxic concentrations. The ES cells were the most sensitive towards the cytotoxic effects of the solvent DMSO while the EC cells were more sensitive when treated with the solvent ethanol.

Progression of coronary artery calcification in diabetics with and without chronic kidney disease

BACKGROUND

Rapid progression of coronary artery calcification (CAC) has been reported among individuals with end-stage renal disease (ESRD). There is limited information on the progression of CAC during earlier stages of diabetic chronic kidney disease (CKD).

METHODS

In a prospective, cohort study of type 2 diabetic individuals (N = 90; normoalbuminuric diabetic controls, 30; diabetic nephropathy, DN, 60), electron-beam computed tomography (EBCT) was repeated at an average interval of 19 months. All scan images were acquired at end-systole to minimize interscan variability. In order to eliminate the dependence of the residual error from interscan variability on baseline CAC scores, square root transformed CAC scores were used for analyses of progression of coronary calcification.

RESULTS

Repeat EBCT scans were completed in 68 subjects (diabetic controls: 23; DN: 45). There was a highly significant relationship between the proportion of subjects with progressive CAC and renal disease-DN who progressed to ESRD, 80%; DN who did not progress to ESRD, 30%; and diabetic controls, 13% (P < 0.001). Similarly, the magnitude of change was significantly related to renal disease (DN who progressed to ESRD > DN who did not progress to ESRD > diabetic controls, P < 0.001). Using logistic regression and controlling for non-dialyzed DN, ESRD and inter-scan interval, advanced age was the only significant variable associated with progression of CAC. Finally, serum creatinine and baseline CAC score emerged as independent predictors for the magnitude of increase in CAC.

CONCLUSION

Progression of CAC is apparent among individuals with DN both before and after ESRD. However, the risk factors associated with progression of CAC may differ at different stages of CKD.

Renal disease: environment, race, or genes?

Diabetic nephropathy is over-represented in people of color. This reflects both environmental and genetic factors. Numerous studies assess the effects of access to care and patient adherence in the development of kidney diseases. After correcting for these factors, genetic influences remain. Genetic approaches to discerning genes that predispose to diabetic nephropathy include candidate gene approaches, linkage analysis, mapping by admixture linkage disequilibrium, and transmission disequilibrium testing. Numerous candidate genes have been identified, although few have been confirmed apart from those representing genes in the renin-angiotensin system. The results of linkage analysis studies have similarly resulted in genomic regions purported to show linkage in a variety of ethnic groups that have most often not been confirmed in other ethnic groups, and sometimes in other groups of similar ethnicity but different phenotype definitions. The chromosomal regions determining glomerular filtration rate do not appear to be localized to the same chromosome as those related to proteinuria. Large cohorts of subjects have now been amassed by numerous research groups, and genome-wide scanning results involving much larger cohorts are anticipated to be published in the next few years. It is hoped that these strategies will ultimately identify chromosomsal regions and/ or genes that confer risk for diabetic nephropathy, and in so doing, provide clues to new therapies.

Serum fetuin-A in nondialyzed patients with diabetic nephropathy: relationship with coronary artery calcification

BACKGROUND

Fetuin-A is the most potent circulating inhibitor of calcium phosphorus precipitation and, possibly, an important mediator of insulin resistance.

METHODS

In order to determine the role of fetuin-A in the high coronary artery calcification (CAC) burden seen in nondialyzed individuals with diabetic nephropathy (DN), post-hoc analyses of data collected from a cross-sectional study of 88 patients with type 2 diabetes mellitus was done [age, 40-65 years; normoalbuminuria, N= 30 (Latinos); DN, N= 58 (Latinos and African Americans)].

RESULTS

The serum levels of fetuin-A were significantly higher among Latinos with DN when compared to either African Americans with DN or Latino diabetics with normoalbuminuria. Upon adjusting the data for race/ethnicity, there was a strong, direct relationship between serum fetuin-A levels and the CAC score (r= 0.22, P= 0.038) in the study cohort; however, a strong interaction between the nephropathy status and relationship of serum fetuin-A levels with CAC score was present (DN: r= 0.36, P= 0.006; diabetic controls, r= 0.0, P= 0.98). Among individuals with DN, the significance of the association persisted even after controlling the data for other predictors of CAC (partial r= 0.33, P= 0.018). Furthermore, there was a significant direct relationship between serum fetuin-A and serum triglycerides (partial r= 0.27, P= 0.01) and albumin (partial r= 0.30, P= 0.005), and an inverse relationship with glomerular filtration rate (r=-0.24, P= 0.03).

CONCLUSION

This first study in early stages of diabetic chronic kidney disease shows that the role of serum fetuin-A may be far more complex than previously described. During predialysis stage of DN, there is a direct relationship between serum fetuin-A levels and CAC score. The reasons for this association in the presence of nephropathy are unclear, but may be secondary to proatherogenic insulin resistance.

Determinants of coronary artery calcification in diabetics with and without nephropathy

BACKGROUND

In the general population, including those with diabetes mellitus, coronary artery calcification (CAC) correlates with atherosclerotic plaque burden. On the other hand, accumulating evidence suggests that disordered mineral metabolism significantly contributes to the vascular calcification in individuals with end-stage renal disease (ESRD).

METHODS

In order to determine the relative contribution of accelerated atherosclerosis and disordered mineral metabolism to CAC in chronic kidney disease, a pilot study of 90 patients with type 2 diabetes mellitus was done [age, 40-65 years; normoalbuminuria, N= 30; diabetic nephropathy (DN), N= 60].

RESULTS

CAC was more prevalent and severe among individuals with DN compared to diabetic controls (odds ratio for prevalence 8.1, 95% CI 2.3-28.5; median scores, 66 vs. 4, P < 0.001). None of the 4 measures of disordered mineral metabolism evaluated in this study (serum calcium, phosphorus, parathyroid hormone, and 1,25 di-hydroxy vitamin D levels) correlated with the prevalence or severity of CAC, or accounted for the differences seen between DN and diabetic controls. On the other hand, the difference in the severity of hypertension (number of antihypertensive medications) appeared to account for the differences in CAC burden seen between DN and diabetic controls.

CONCLUSION

This first such study of nondialyzed individuals with DN suggests that, unlike ESRD patients, the high CAC burden seen at earlier stages of diabetic chronic kidney disease is probably unrelated to disordered mineral metabolism. The relationship between the severity of hypertension and CAC burden provides a probable target for intervention in the predialysis phase of DN.

Comparison of economic and environmental impacts between disposable and reusable instruments used for laparoscopic cholecystectomy

BACKGROUND

The economic and environmental effects were compared between disposable and reusable instruments used for laparoscopic cholecystectomy. Special consideration was given to the processing of reusable instruments in the Miele G 7736 CD MCU washer disinfector and the resultant cost of sterilization.

METHODS

The instruments frequently used in their disposable form were identified with the help of surgeons. Thus, of all the instruments used for laparoscopic cholecystectomy, the disposable and reusable versions of trocars, scissors, and Veress cannula were compared.

RESULTS

For the case examined in this study, the performance of laparoscopic cholecystectomy with disposable instruments was 19 times more expensive that for reusable instruments. The higher cost of using disposable instruments is primarily attributable to the purchase price of the instruments. The processing of reusable instruments has little significance in terms of cost, whereas the cost for disposing of disposable instruments is the least significant factor. The number of laparoscopic cholecystectomies performed per year does not substantially influence cost. In the authors' opinion, assessment of the environmental consequences shows that reusable instruments are environmentally advantageous.

CONCLUSIONS

Considering the upward pressure of costs in hospitals, disposable instruments should be used for laparoscopic cholecystectomy only if they offer clear advantages over reusable instruments.

Oxidant stress in kidneys of spontaneously hypertensive rats involves both oxidase overexpression and loss of extracellular superoxide dismutase

Oxidant stress is an important contributor to renal dysfunction and hypertension. We have previously demonstrated that regulation of renal oxygen consumption by nitric oxide (NO) is impaired in the kidney of spontaneously hypertensive rats (SHR) due to increased superoxide production. We further explored the mechanisms of enhanced oxidant stress in the kidney of SHR. Suppression of cortical oxygen consumption by bradykinin (BK) or enalaprilat (Enal), which act through stimulation of endogenous NO, was impaired in SHR (BK: -14.1 +/- 1.2%; Enal: -15.5 +/- 1.2%) and was restored by addition of apocynin, an inhibitor of assembly of the NAD(P)H oxidase complex (BK: -21.0 +/- 0.6%; Enal: -25.3 +/- 1.4%), suggesting this as the source of enhanced superoxide production. Addition of an angiotensin type 1 receptor blocker, losartan, also restored responsiveness to control levels (BK: -22.0 +/- 1.1%; Enal: -23.6 +/- 1.3%), suggesting that ANG II is responsible for enhanced oxidase activity. A similar defect in responsiveness to BK and Enal could be induced in Wistar-Kyoto kidneys by ANG II and was reversed by a superoxide scavenger (tempol), apocynin or losartan. Immunoblotting of cortical samples demonstrated enhanced expression of endothelial NO synthase (eNOS 1.9x) and NAD(P)H oxidase components (gp91(phox) 1.6x and Rac-1 4.5x). Expression of SOD-1 and -2 were unchanged, but SOD-3 was significantly decreased in SHR (0.5x). Thus NO bioavailability is impaired in SHR owing to an ANG II-mediated increase in superoxide production in association with enhanced expression of NAD(P)H oxidase components, despite increased expression of eNOS. Loss of SOD-3, an important superoxide scavenger, may also contribute to enhanced oxidant stress.

Monitoring of teratogenic effects in vitro by analysing a selected gene expression pattern

The development of in vitro methods for regulatory embryotoxicity testing is challenging since the understanding of chemical effects on the mammalian development is still poor. The aim of the project is to identify marker genes during in vitro cell differentiation of murine embryonic stem cells, in order to predict chemical effects on cell differentiation of specific target tissues. The present study is focusing on the expression pattern by using semi-quantitative reverse transcriptase (RT)-PCR of key genes involved in cardiomyocytes development; i.e. Oct-4, Brachyury, Nkx2.5 and alpha myosin heavy chain (alpha-MHC). Two reference chemicals with well-known in vivo data have been analysed by using this approach: retinoic acid and lithium chloride. Retinoic acid has been selected as a teratogen affecting several target tissues, whereas lithium chloride has been described to affect the development of the cardiovascular system. We demonstrate that retinoic acid already affects in the early stage of germ layer formation, which was demonstrated by a change of Oct-4 and Brachyury gene expression. As we expected, the expression of cardiac specific genes (Nkx2.5, alpha-MHC) has been also modified. In contrary, the Oct-4 and Brachyury expression was not changed by lithium treatment. In this case, we observed a modification in the normal gene expression pattern, for alpha-MHC and Nkx2.5, demonstrating that lithium chloride affects the later stage of heart development. These data suggest that the inclusion of selective target organ genes in an established embryotoxicity test allows to predict effects of chemicals and drugs to the heart development.

Supercritical carbon dioxide extraction of selected medicinal plants--effects of high pressure and added ethanol on yield of extracted substances

The possibilities and limitations of supercritical fluid extraction of natural products of low, medium and high polarity under very high pressure and with polar modifiers has been investigated. The medicinal herbs marigold (Calendula officinalis), hawthorn (Crataegus sp.) and chamomile (Matricaria recutita) were used as models in this study. Extraction profiles and the spectra of extractable metabolites were recorded following extraction with mixtures of carbon dioxide:ethanol of varying proportions (0-20% ethanol) and at various pressures in the range 300-689 bar. Components were identified by HPLC-PAD-MS or GC-MS and quantified by HPLC or GC as appropriate. Extraction yields under the varying conditions depended to a large extent on the profiles of secondary metabolites present in the three drugs. Whereas the extractability of lipophilic compounds increased substantially at pressures above 300 bar, the yields of polyphenolic and glycosidic compounds remained low even at 689 bar and with 20% modifier in the extraction fluid.

Coronary artery, aortic wall, and valvular calcification in nondialyzed individuals with type 2 diabetes and renal disease

BACKGROUND

Individuals with end-stage renal disease (ESRD) have highly prevalent and severe vascular and valvular calcification. We undertook this study to test the hypothesis that vascular and valvular calcification begins and is often severe long before diabetic renal disease progresses to ESRD.

METHODS

A total of 32 nondialyzed individuals with type 2 diabetes mellitus and diabetic renal disease (albumin excretion rate>30 microg/min) [mean glomerular filtration rate (GFR), 49.8 +/- 6.1 mL/min/1.73 m2] were identified and compared with a group of 18 normoalbuminuric diabetics. We used 3:1 matching to identify 95 nondiabetic controls without renal disease, matched for age, gender, ethnicity, and the presence/absence of dyslipidemia, hypertension, and known coronary artery disease (CAD).

RESULTS

Using electron beam computed tomography (CT), the prevalence of coronary artery calcification was significantly greater among diabetic renal disease individuals (prevalence, 94% vs. 59%, P < 0.001; median score, 238 vs. 10, P < 0.001) than the nondiabetic controls. The coronary artery calcification scores were significantly more severe among diabetic renal disease individuals than either the diabetic or nondiabetic controls. Among individuals with diabetic renal disease, the coronary artery calcification and aortic wall calcification scores were several-fold greater among those with known CAD than among those without. There was also a significantly greater prevalence of aortic and mitral valve calcification among diabetic renal disease individuals than nondiabetic controls (aortic, 23% vs. 6%, P = 0.03; mitral, 25% vs. 2%, P < 0.001). Multivariate analysis using all three groups reproduced these findings and also consistently identified age and diabetic renal disease as additional predictors for the presence or severity of coronary artery and aortic wall calcification.

CONCLUSION

In this first, systematic analysis among nondialyzed individuals with diabetic renal disease, these data demonstrate that vascular and valvular calcification is present and often severe long before the disease progresses to ESRD. The data also suggest that the coronary artery and aortic wall calcification may represent atherosclerosis.

Preparative purification of the major anti-inflammatory triterpenoid esters from Marigold (Calendula officinalis)

A method for the efficient preparative purification of faradiol 3-O-laurate, palmitate and myristate, the major anti-inflammatory triterpenoid esters in the flower heads of the medicinal plant Calendula officinalis has been developed. Gram quantities of the individual compounds were obtained with 96 to 98% purity by a combination of supercritical fluid extraction (SFE), normal-phase and reversed-phase column chromatography. During the work-up of the faradiol esters, accompanying minor compounds of the triterpene ester fraction were purified and identified by spectroscopic means as maniladiol 3-O-laurate and myristate.

Norepinephrine release is reduced in cardiac tissue of Type 2 diabetic patients

AIMS/HYPOTHESIS

The aim of this study was to assess whether cardiac catecholamine release is affected in patients with Type 2 diabetes mellitus.

METHODS

A trial tissue was obtained from 19 diabetic (Type 2) and 43 non-diabetic patients undergoing coronary surgery. Endogenous norepinephrine release was examined under baseline conditions as well as during electrical field stimulation (effective voltage 5 V, stimulation frequency 4 Hz, pulse width 2 msec) by high performance liquid chromatography and electrochemical detection. Cardiac function and arterial blood pressure was assessed from coronary angiography.

RESULTS

In atrial tissue from diabetic patients, stimulation-induced norepinephrine release was reduced by 25% compared with non-diabetic patients, while baseline norepinephrine release did not differ between both groups. Preoperative plasma glucose and haemoglobin A(1C) concentrations were increased in patients with diabetes, however, no relation was found to catecholamine release. Diabetic and non-diabetic patients did not differ regarding left ventricular ejection fraction and arterial blood pressure.

CONCLUSION/INTERPRETATION

Cardiac norepinephrine release is suppressed in patients with Type 2 diabetes which could contribute to sympathetic neuropathy. The difference of norepinephrine release in diabetic and non-diabetic patients was independent of cardiac function and arterial blood pressure.

In vivo functional proteomics: mammalian genome annotation using CD-tagging

A self-inactivating CD-tagging retroviral vector was used to introduce epitope and GFP tags into genes and proteins in NIH 3T3 cells. Several hundred cell clones, each expressing GFP fluorescence in a distinctive pattern, were isolated. Molecular analysis showed that a wide variety of genes and proteins, some known and some newly discovered, had been tagged. The analysis also revealed that, in the great majority of instances, the abundance and cellular location of the tagged protein mirrored that of its untagged counterpart. This approach provides a systematic means for the functional annotation of mammalian genomes and proteomes in living cells.

Peripheral arterial disease is not associated with an increased prevalence of intradialytic cramps in patients on maintenance hemodialysis

BACKGROUND/AIMS

Peripheral arterial disease (PAD) has been suggested as a contributing factor to the development of intradialytic muscle cramps in patients on maintenance hemodialysis.

METHODS

To test this hypothesis, 122 patients from two dialysis centers were studied. The presence of PAD was determined by measurement of the ankle-brachial index (ABI) in the lower extremities of patients pre- and postdialysis. The experience of intradialytic cramps was assessed using patient history and review of medical records.

RESULTS

PAD defined as a predialysis ABI < or =0.90 had an overall prevalence of 16.4% among patients studied. The prevalence of PAD was age-dependent, reaching 37.5% in patients 80-89 years old. Intradialytic muscle cramps were common, with 52.1% of patients reporting cramps within the previous two months, but there was no relationship between cramps during dialysis and PAD (p > 0.05).

CONCLUSIONS

PAD was common in hemodialysis patients, but there was no association between the presence of PAD and the prevalence of intradialytic muscle cramps.

A case of imported paracoccidioidomycosis in a German legionnaire

We report on a case of the chronic form of paracoccidioidomycosis with swelling and ulcerations of the mouth in a German legionnaire who also suffered from a chronic bronchitis. The patient had worked for many years in Brazil, an area endemic for the disease. Infection due to Paracoccidioides brasiliensis was diagnosed in Germany, more than 10 years after the patient's return. Diagnosis was established by the presence of yeast cells with multipolar budding in the tissue of the oral lesion. Furthermore, the fungus was grown in a liquid Leishmania culture medium. Identification of the fungus was based on morphology and genetic sequencing. Furthermore, IgG antibodies against a 43-kDa antigen of P. brasiliensis were detected in a western blot. After itraconazole therapy (400 mg day(-1)) for 4 weeks, the lesions had disappeared almost completely, but the therapy was continued for further 5 months to avoid relapse of the infection.

Further evidence for the decay K+ -->pi+nu(nu)

Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211<P<229 MeV/c, bringing the total for the combined data set to two. Including all data taken, the backgrounds were estimated to contribute 0.15+/-0.05 events. The branching ratio is B(K+-->pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).

Clinical and demographic predictors of exercise capacity in end-stage renal disease

Patients on maintenance hemodialysis therapy for end-stage renal disease have reduced exercise tolerance. Multiple processes related to uremia and hemodialysis have been implicated in the pathophysiology of this impairment. However, limited data are available to identify the separate and combined effects of clinical factors on the degree of impairment for individuals within this population. For this purpose, data from 193 patients who had undergone exercise testing for two clinical trials were retrospectively analyzed. Univariate and multiple linear regression analyses were used to identify demographic and clinical correlates of peak exercise oxygen uptake (VO2). Peak VO2 averaged 18.5 +/- 6.4 mL/min/kg. On univariate analysis, peak VO2 correlated positively with male sex and hemoglobin, serum albumin, and serum creatinine concentrations and correlated negatively with dialytic age and diagnosis of diabetes or chronic heart failure. In a multiple linear regression model, sex, hemoglobin concentration, age, and diagnosis of diabetes each remained statistically significant. Together, factors included in the model accounted for 41% of the variability in peak VO2 (P = 0.0001). Among factors not correlating significantly with peak VO2 were resting blood pressure, serum carnitine level, and urea clearance assessed by Kt/V. Findings show the range of exercise impairment among clinically stable ambulatory hemodialysis patients, which may be sufficient to interfere with normal daily activities for many of these patients. Although this impairment may be broadly attributable to physiological consequences of uremia, the degree of impairment for individual patients is predicted by demographic factors, coexistent disease, and factors potentially modified by medical therapeutics.

IgM anticardiolipin antibodies are associated with stenosis of vascular access in hemodialysis patients but do not predict thrombosis

AIM

The prevalence of anticardiolipin antibodies (ACA) is elevated amongst hemodialysis patients as compared with the general population. Previous studies have disagreed as to whether the presence of ACA represents a risk factor for access thrombosis. Other risk factors for access thrombosis (decreased blood flow, elevated venous pressure) have also been described.

MATERIALS AND METHODS

We performed a combination retrospective and prospective cohort study of a single outpatient dialysis unit to assess the association between these potential risk factors and access thrombosis. ACA, access blood flow, presence of stenosis, and venous pressures were measured in 100 patients. Information on episodes of access thrombosis was gathered for 12 months prior to and 12 months after ACA measurement.

RESULTS

ACA were present in 19% of patients with equal numbers of IgG- and IgM-ACA. The presence of IgM-ACA was significantly associated with the use of aspirin and the presence of stenosis by Doppler at the time of ACA testing (p < 0.05). A logistic regression model was used to estimate the association between clinical factors and access thrombosis. In this multivariate analysis, the presence of access stenosis and a history of access thrombosis were both significantly associated with the development of access thrombosis. Adjusted for these variables, neither IgG- nor IgM-ACA was significantly associated with access thrombosis. The presence of an ACA was not associated with episodes of access thrombosis in either the prospective or retrospective analyses.

CONCLUSION

Further investigation is required to determine if the association between aspirin use and IgM-ACA, or of IgM-ACA and access stenosis, has implications for underlying pathogenetic mechanisms of access stenosis.

Simvastatin reverses impaired regulation of renal oxygen consumption in congestive heart failure

Nitric oxide (NO) production by endothelial nitric oxide synthase (eNOS) regulates renal O(2) consumption. This mechanism is impaired in heart and kidney of dogs with heart failure (CHF). Simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase, increases eNOS expression in the endothelium. Therefore, we studied whether simvastatin treatment could restore the regulation of renal O(2) consumption by stimulators of NO production in dogs with CHF. Renal O(2) consumption was measured after stimulation of NO production with bradykinin, ramiprilat, or amlodipine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP). Simvastatin delayed the time to euthanasia in dogs with CHF (35 +/- 1.0 vs. 29 +/- 1.2 days; P < 0.01). In normal dogs, bradykinin (10(-4) M), ramiprilat (10(-4) M), amlodipine (10(-5) M), and SNAP (10(-4) M) significantly reduced O(2) consumption in the renal cortex (-31.8 +/- 0.9, -30.3 +/- 1.1, -30.1 +/- 2.0, -46.9 +/- 1.0%) and renal medulla (-29.7 +/- 2.1, -33.0 +/- 2.7, -30.8 +/- 2.2, -46.8 +/- 1.1%). Responses to bradykinin, ramiprilat, and amlodipine were significantly attenuated in CHF but were partially or completely restored by simvastatin. Responses to SNAP were unaffected. These data demonstrate that treatment with simvastatin improves renal production of NO in CHF, restoring the normal regulation of renal O(2) consumption by NO.

Brief clinical report: duodenal laceration presenting as massive hematemesis and multiple intraabdominal abscesses after laparoscopic cholecystectomy

SUMMARY

Laparoscopic cholecystectomy is considered the gold standard for gallstone disease. Nevertheless, possible severe complications must not be underestimated. Bowel injuries are uncommon, but they are one of the most lethal technical complications of laparoscopic surgery. These injuries were commonly unrecognized at the time of procedures and were diagnosed later when the patients experienced sepsis, peritonitis, intraabdominal abscess, or enterocutaneous fistula. Although duodenal lacerations have been reported with laparoscopic cholecystectomies, they seem to be rare; approximately 30 such cases have been documented previously in the English literature. We report the case of a patient with thermal duodenal injury caused by elective laparoscopic cholecystectomy at an outside center presenting as massive hematemesis and multiple intraabdominal abscesses on the ninth postoperative day. The diagnosis and management of this rare complication of laparoscopic cholecystectomy are described, and the literature is reviewed.

Prevention of chronic atrial fibrillation by pacing in the region of Bachmann's bundle: results of a multicenter randomized trial

INTRODUCTION

Atrial pacing locations that decrease atrial activation and recovery time may be preferable in patients with a history of atrial arrhythmias. This multicenter prospective randomized study compared the efficacy of Bachmann's bundle (BB) region pacing to right atrial appendage (RAA) pacing in patients with recurrent paroxysmal atrial fibrillation (AF).

METHODS AND RESULTS

Patients with standard pacing indications (n = 120, 70+/-11 years) were randomized to atrial pacing in either the RAA (n = 57) or BB region (n = 63). Implantation time was similar between groups (88+/-36 min [n = 38] for BB vs 83+/-34 min [n = 34] for RAA). No differences in pacing threshold, impedance, or sensing between BB and RAA groups were observed at implantation or after the 6-week, 6-month, and 1-year follow-up periods. Average length of follow-up was 12.6+/-7.4 months for the BB group and 11.8+/-8.0 months for the RAA pacing group. The percentage of atrial pacing was similar between groups (61%+/-34% RAA vs 65%+/-31% BB at 2 weeks after implant). BB atrial pacing significantly (P < 0.05) shortened p wave duration compared with sinus rhythm (123+/-21 msec vs 132+/-21 msec, n = 50) 2 weeks after implant. In contrast, p wave duration was longer during atrial pacing from the RAA position compared with sinus rhythm (148+/-23 msec vs 123+/-23 msec, n = 37). Additionally, p wave duration was shorter during BB pacing than during RAA pacing. Patients with BB pacing had a higher (P < 0.05) rate of survival free from chronic AF (75%) compared with patients with RAA pacing (47%) at 1 year.

CONCLUSION

BB region pacing is safe and effective for attenuating the progression of AF.

Vascular access problems in dialysis patients: pathogenesis and strategies for management

Repetitive hemodialysis was made possible through the development of a chronic means of accessing the circulation. This was accomplished through the use of arteriovenous fistulae or grafts, using autologous veins or synthetic materials. Although the arteriovenous fistula remains the access of choice, synthetic arteriovenous grafts are used in most patients because of problems with late referral to a nephrologist and poor vasculature. This article describes the means of accessing the circulation for hemodialysis, the pathogenesis of access failure through progressive stenosis followed by thrombosis, methods of detecting access dysfunction before thrombosis, and therapeutic options. Although angiographic or surgical intervention remain the mainstays of management, medical treatments to decrease stenosis and delay thrombosis are currently under investigation.