Epithelial to mesenchymal transition (EMT) seems to be regulated differently in endometriosis and the endometrium

PURPOSE

Epithelial-mesenchymal transition (EMT) endows cells with migratory and invasive properties, a prerequisite for the establishment of endometriotic lesions. However, the role EMT might play in the pathophysiology of endometriosis is still unknown. Therefore, we examined five recognized markers for EMT in endometrium and endometriosis: E-cadherin, N-cadherin, Twist, Snail and Slug.

METHODS

Immunohistochemistry was used for peritoneal, ovarian and rectovaginal endometriotic lesions (n = 27) and endometrium (n = 13). Reverse transcription polymerase chain reaction was applied to tissue samples and primary cell cultures of endometriotic lesions (n = 9) and endometrium (n = 8).

RESULTS

In endometriosis and endometrium E-cadherin, N-cadherin, Twist, Snail and Slug were expressed on protein and mRNA level. E-cadherin expression was strong in epithelial cells, but single E-cadherin-negative cells were frequently present in endometriosis. In endometriosis N-cadherin, Twist and Snail expression were upregulated in comparison with endometrium. The expression of E- and N-cadherin was inversely correlated, while that of N-cadherin and Twist was positively correlated.

CONCLUSION

This study strongly suggests that EMT may be regulated differently in endometriosis and the endometrium. Future research should further elucidate the regulation of EMT in the endometrium and endometriosis.

Widespread unidirectional transfer of mitochondrial DNA: a case in western Palaearctic water frogs

Interspecies transfer of mitochondrial (mt) DNA is a common phenomenon in plants, invertebrates and vertebrates, normally linked with hybridization of closely related species in zones of sympatry or parapatry. In central Europe, in an area north of 48 degrees N latitude and between 8 degrees and 22 degrees E longitude, western Palaearctic water frogs show massive unidirectional introgression of mtDNA: 33.7% of 407 Rana ridibunda possessed mtDNA specific for Rana lessonae. By contrast, no R. lessonae with R. ridibunda mtDNA was observed. That R. ridibunda with introgressed mitochondrial genomes were found exclusively within the range of the hybrid Rana esculenta and that most hybrids had lessonae mtDNA (90.4% of 335 individuals investigated) is evidence that R. esculenta serves as a vehicle for transfer of lessonae mtDNA into R. ridibunda. Such introgression has occurred several times independently. The abundance and wide distribution of individuals with introgressed mitochondrial genomes show that R. lessonae mt genomes work successfully in a R. ridibunda chromosomal background despite their high sequence divergence from R. ridibunda mtDNAs (14.2-15.2% in the ND2/ND3 genes). Greater effectiveness of enzymes encoded by R. lessonae mtDNA may be advantageous to individuals of R. ridibunda and probably R. esculenta in the northern parts of their ranges.

Ensembl 2005

The Ensembl (http://www.ensembl.org/) project provides a comprehensive and integrated source of annotation of large genome sequences. Over the last year the number of genomes available from the Ensembl site has increased by 7 to 16, with the addition of the six vertebrate genomes of chimpanzee, dog, cow, chicken, tetraodon and frog and the insect genome of honeybee. The majority have been annotated automatically using the Ensembl gene build system, showing its flexibility to reliably annotate a wide variety of genomes. With the increased number of vertebrate genomes, the comparative analysis provided to users has been greatly improved, with new website interfaces allowing annotation of different genomes to be directly compared. The Ensembl software system is being increasingly widely reused in different projects showing the benefits of a completely open approach to software development and distribution.

Ensembl 2004

The Ensembl (http://www.ensembl.org/) database project provides a bioinformatics framework to organize biology around the sequences of large genomes. It is a comprehensive and integrated source of annotation of large genome sequences, available via interactive website, web services or flat files. As well as being one of the leading sources of genome annotation, Ensembl is an open source software engineering project to develop a portable system able to handle very large genomes and associated requirements. The facilities of the system range from sequence analysis to data storage and visualization and installations exist around the world both in companies and at academic sites. With a total of nine genome sequences available from Ensembl and more genomes to follow, recent developments have focused mainly on closer integration between genomes and external data.

[Evaluation of passive cardiomyoplasty using left- and right-ventricular volume measurements by EBCT and MRI in patients with chronic congestive heart failure]

PURPOSE

To evaluate the efficacy of passive cardiomyoplasty with the determination of biventricular volumes, global systolic function as well as left-ventricular muscle mass.

MATERIALS AND METHODS

In 19 patients with congestive heart failure of idiopathic or ischemic origin, a polyester mesh-graft was implanted around both ventricles for stabilization and functional support. Before and three months after surgery, 15 patients underwent EBCT and 4 patients with impaired renal function underwent MRI, for the evaluation of the volume and ejection fraction of both ventricles.

RESULTS

EBCT demonstrated a decrease from 385 to 310 ml in LV-EDV, from 312 to 242 ml in LV-ESV, from 209 to 160 ml in RV-EDV and from 149 to 87 ml in RV-ESV, and an increase from 20 to 26% in LV-EF and from 37 to 50% in RV-EF as well as a reduction of LV-MM from 300 to 274 g (p < 0.05 each). Similar results were obtained by MRI.

CONCLUSION

Following passive cardiomyoplasty, EBCT and MRI revealed an improvement of the global systolic function as well as a reduction of biventricular volumes and left-ventricular muscle mass.

[Minimal invasive surgery for pHPT--which patients will profit?]

BACKGROUND

Standard for treatment of pHPT has been the exploration of the neck and extirpation of the macroscopic identified adenoma for a long time. Since the Quick-PTH-Assay is available as intraoperative control of success, it is possible to extirpate a preoperativeley localized adenoma without identifying the normal parathyroid glands. Since the accuracy of the preoperative localization is essential for a minimally invasive or endoscopic procedure, we analyzed retrospectively the accuracy of ultrasound and mibiscan of our patients, operated due to pHPT in our facility.

METHODS

Between 1995 and 2002 119 patients were operated due to HPT in our facility. Sensitivity, specificity, positive- and negative-predictive value for diagnosis and correct localisation of a singular adenoma by ultrasound and/or mibiscan were determined.

RESULTS

We found a singular adenoma in 94 patients, a carcinoma in 1 patient, 6-times a double-adenoma and in 18 cases a hyperplasia of all parathyroid glands. Sensitivity, specificity, positive- and negative-predictive value for diagnosis and correct localisation of a singular adenoma were 52 %, 41 %, 60 % and 27 % rsp., when the results of mibiscan and ultrasound were used.

DISCUSSION

Related to the preoperative imaging, a single gland exploration and extirpation would have been possible in 70 % of our patients with pHPT. However, in 40 % of these patients the 100 % reliable Quick-PTH-Assay would have shown, that the adenoma has not been removed successfully in the first attempt.

A critical evaluation of results of partial left ventriculectomy

BACKGROUND

Because of the variation in the surgical procedures designed to reduce ventricular radius, along with differences in hospital care, it is difficult to disentangle the factors that may contribute to the success or failure of the partial left ventriculectomy.

METHODS AND RESULTS

We undertook partial left ventriculectomy in 18 patients, 10 suffering from idiopathic dilated cardiomyopathy and 8 from ischemic heart disease. We assessed the amount of reduction in wall stress, the systolic thickening of the ventricular wall, and the extent of connective tissue in the excised segment of the wall. Of the overall group, six patients died, three from infarction, one of stroke, one with asystole, and one with ventricular fibrillation. The mean decrease in measured mesh tension was 40% (p < 0.001). Most patients exhibited improvements postoperatively in terms of the systolic thickening of the posterior and superior free walls of the left ventricle. In those in whom the events could be monitored, life-threatening arrhythmias posed complications in three of four patients with ischemic heart disease, and in two of six patients suffering from idiopathic dilated cardiomyopathy. In one patient, death was associated with a transmural alignment of fibrous tissue.

CONCLUSIONS

Our measured reductions in myocardial mesh tension were in keeping with the anticipated theoretical reduction in wall stress expected from partial ventriculectomy. The basic concept underscoring surgical maneuvers to reduce ventricular radius, therefore, is sound. A potential trap is the resection of the marginal artery. Critical myofibrosis was a rare complication. Arrhythmias, which are common, can successfully be treated by implantation of antitachycardic and defibrillatory devices.

Persistent multiple organ microcirculatory disorders in severe acute pancreatitis: experimental findings and clinical implications

This study characterizes microcirculatory changes (capillary blood flow, capillary permeability, and leukocyte rolling) in the pancreas, colon, liver, and lungs at different stages of severe acute pancreatitis (AP) in a well-established rat model using intravital microscopy and computerized image analysis. The results demonstrate that microcirculatory disorders in severe AP are not confined to the pancreas but can also be found in the colon, liver, and lungs; that they extend beyond the early stage of AP and persist for 48 hr (and longer); and that they not only affect capillary blood flow but also involve prolonged changes of capillary permeability and leukocyte endothelial interaction. These findings may explain previous observations that therapeutic strategies aimed at enhancing microcirculation improve outcome in AP even if therapy is delayed and pancreatic necrosis can no longer be influenced. Since these systemic microcirculatory disturbances may contribute to AP-associated multiple organ dysfunction syndrome, further studies are warranted to evaluate whether improvement of microcirculation stabilizes organ function in AP and how long this may be effective after disease onset.

Persistent multiple organ microcirculatory disorders in severe acute pancreatitis: experimental findings and clinical implications

This study characterizes microcirculatory changes (capillary blood flow, capillary permeability, and leukocyte rolling) in the pancreas, colon, liver, and lungs at different stages of severe acute pancreatitis (AP) in a well-established rat model using intravital microscopy and computerized image analysis. The results demonstrate that microcirculatory disorders in severe AP are not confined to the pancreas but can also be found in the colon, liver, and lungs; that they extend beyond the early stage of AP and persist for 48 hr (and longer); and that they not only affect capillary blood flow but also involve prolonged changes of capillary permeability and leukocyte endothelial interaction. These findings may explain previous observations that therapeutic strategies aimed at enhancing microcirculation improve outcome in AP even if therapy is delayed and pancreatic necrosis can no longer be influenced. Since these systemic microcirculatory disturbances may contribute to AP-associated multiple organ dysfunction syndrome, further studies are warranted to evaluate whether improvement of microcirculation stabilizes organ function in AP and how long this may be effective after disease onset.

Magnetic resonance imaging of stentless xenografts for reconstruction of right ventricular outflow tract

The objective was to overcome allograft shortage during the Ross operation; stentless xenografts were carefully evaluated for hemodynamic behavior and valve deterioration during medium term follow-up. Between January 10, 1994 and January 4, 1996 nine adult patients (age 31-51 years) underwent aortic valve replacement with an autologous pulmonary valve and right ventricular outflow tract reconstruction with the Edwards Prima or Medtronic Freestyle xenograft. One patient was dead early and one late, both from noncardiac reasons. Forty-eight to 66 months follow-up was available for 7 patients and was performed with physical examination in the outpatient clinic, transthoracic echocardiography (TTE), and magnetic resonance imaging (MRI). Two patients received 29-mm valves and the remaining 27-mm valves. No reoperation became necessary during follow-up. Preoperative left ventricular ejection fraction ranged from 20% to 84%, median 61%, mean 59% +/- 18%. At latest follow-up left ventricular ejection fraction was 49% to 70%, median 57%, mean 58% +/- 8%. TTE showed no calcification of the xenograft wall or cusps. MRI revealed good autograft function with no evidence of stenosis in any patient. Four patients showed no and three trivial regurgitation. Right ventricular outflow tract-stenosis could not be seen in any patient. Calculated gradients of the xenograft valves ranged from 2 to 6 mm Hg, median 3 mm Hg (mean 3.1 +/- 2.4 mm Hg) and calculated EOA ranged from 2.0 to 4.0 cm(2), median 2.8 cm(2). MRI supported these findings and showed pliable xenograft cusps in all patients. Right ventricular function was well preserved in all patients. In adult patients right ventricular outflow tract reconstruction with stentless xenografts can be performed safely and intermediate-term results are encouraging. During medium-term (5-7 years) follow-up no calcification or deterioration of valve function occurred with excellent hemodynamic behavior.

Passive containment and reverse remodeling by a novel textile cardiac support device

BACKGROUND

Progressive remodeling and dilation of cardiac chambers is responsible in part for myocardial dysfunction in chronic heart failure. Preclinical studies with suitable animal models indicate that a passive cardiac constraint device can promote reverse remodeling, with improvement in cardiac function. We hypothesize that such a device could provide benefit for stable heart failure patients in New York Heart Association (NYHA) class II and III.

METHODS AND RESULTS

From April 1999 to March 2000, 27 patients received Acorn's Cardiac Support Device (CSD) during an initial safety/feasibility study. In 11 patients, the only surgical measure was CSD placement. Most patients suffered from idiopathic cardiomyopathy; 4 were in NYHA class II, one was in class II/III, and 6 were in class III. All were stable on intensive medical treatment. The CSD, a textile polyester device, was fitted snugly around the heart during surgery. All patients survived surgery and recovered smoothly. Three months after surgery, 56% of patients were in NYHA class I, 33% were in class II, and 11% were in class II/III. Echocardiography showed an improvement in left ventricular ejection fraction from an average of 22% to 28% and 33% at 3 and 6 months, respectively. Simultaneously, the left ventricular end-diastolic dimension decreased from 74 mm to 68 mm and 65 mm, respectively. Mitral valve regurgitation (on a scale of 0 to 4+) decreased from 1.3 to 0.7 by 3 months. Quality-of-life indices correlated with the apparent reversal of ventricular remodeling. Preoperative cardiac medications remained virtually unchanged after implant.

CONCLUSIONS

In the short- and intermediate-term, CSD implantation seems to ameliorate symptoms and improve cardiac and functional performance in heart failure patients. Worldwide randomized trials are currently underway.

[Indications, technique and initial results of passive cardiomyoplasty]

The cardiac support device (CSD, Acorn Cardiovasc. Inc.), a knitted polyester tissue, is surgically placed over the ventricles to prevent further dilatation of the heart. The aim of this study was to evaluate the feasibility and safety of CSD implantation in patients with advanced heart failure from cardiomyopathy of either idiopathic or ischemic origin. From April 1999, 23 patients received the CSD. In 8 patients the CSD implantation was the only surgical measure; in 12 patients a concomitant mitral valve repair was performed. In three more patients, the CSD implantation was combined with other surgical procedures. The CSD was placed while on bypass with the heart beating, attached to the AV groove and tailored anteriorly to snugly fit the ventricles. There were no intraoperative deaths or complications. Two patients died early postoperatively (4 d, 21 d); 1 late death occurred (44 d postop). The deaths were not considered to be device related. There were no CSD-related adverse events. Six months postoperatively all patients improved by at least one NYHA class. Echocardiography at 6 months revealed an increase in LVEF; the LVEDD decreased accordingly. Mitral valve regurgitation improved in all patients. These findings indicate that the CSD is safe, and improves heart failure symptoms and left ventricular function. Additional studies have to confirm these results.

Linksventrikuläre Volumenreduktion: Prä- und postoperative Evaluierung mit der Cine MRT

AIM

To evaluate the role of cine magnetic resonance imaging (MRI) in the preoperative assessment and postoperative follow-up of patients undergoing left ventricular (LV) reduction surgery.

PATIENTS AND METHODS

6 patients with cardiomegaly were examined on a 1.5 T MR imager before and after LV reduction surgery. The heart was imaged along the short and long axes using a breath-hold ECG-triggered cine gradient-echo sequence for assessing ventricular and valvular morphology and function and performing volumetry (end-diastolic and end-systolic volumes, ejection fraction).

RESULTS

Postoperatively, the mean ejection fraction increased from 21.7% to 33.4% and the end-diastolic and end-systolic left ventricular volumes decreased in all patients (304.0 and 252.5 ml before to 205.0 and 141.9 ml after surgery). Mean myocardial mass decreased slightly from 283.8 g to 242.7 g. Differences were significant for all parameters (p < 0.05). MRI allowed for the reliable assessment of post-operative valve morphology and yielded additional findings such as the presence of mitral valve insufficiency or ventricular thrombus.

CONCLUSIONS

Cine MRI provides relevant information prior to left ventricular reduction surgery and reliably depicts functional and morphological changes in the early post-operative follow-up.

Safety and feasibility of a cardiac support device

The Cardiac Support Device (CSD), a preformed-knitted polyester device surgically placed over the cardiac ventricles, prevents left ventricular (LV) remodeling and improves LV ejection fraction (EF) in dogs with heart failure (HF). This study was designed to examine the safety of the CSD in patients with advanced HF. As of December 31, 1999, the CSD was implanted into 22 patients with myocardial disease. Ten patients had concomitant mitral valve repair, two patients had valve replacement (one patient aortic and one patient mitral), one patient had LV assist device (LVAD) placement, and eight patients received only the CSD. The CSD was placed while on bypass with the heart beating, attached to the epicardium groove, and tailored anteriorly to snugly fit the ventricles. There were no intraoperative deaths or complications. Two patients died early from non-CSD-related causes 4 and 23 days postoperatively; one late death occurred. Of the remaining 19 patients, none had any CSD-related adverse events during an average 3.5 +/- 0.4 month follow-up. All patients had completed 3-month follow-up. No patients had evidence of constrictive and/or restrictive physiology. Mitral valve regurgitation (MVR) improved in all patients. [table: see text] Initial findings indicate that the CSD is safe and improves heart failure symptoms and LV function. Additional studies and longer follow-up are needed to confirm these results.

Risk factors for prolonged ventilation after cardiac surgery using APACHE II, SAPS II, and TISS: comparison of three different models

OBJECTIVE

To identify the risk for prolonged mechanical ventilation in cardiac surgical patients.

DESIGN

Prospective study with retrospective combination of a second database.

PATIENTS

Six hundred and eighty-seven patients after cardiac surgery over a period of 12 months.

MEASUREMENTS

Demographic data were recorded preoperatively, and surgical procedures intraoperatively using a surgical database designed for quality control. Length of ICU and hospital stay, and hospital outcome were recorded. Severity of illness was assessed daily using APACHE II, SAPS II, and Organ Failure Score. Intensity of treatment and nursing care was monitored by means of the Therapeutic Intervention Scoring System (TISS). Univariate and multivariate analyses were performed using logistic regression. The predictive value of the identified variables was tested by the Wilcoxon test using the receiver operating characteristic curve.

MAIN RESULTS

Sixty-two patients (9.0%) were ventilated for > 48 h and accounted for 42.8% of the total costs in the ICU. The pre- and intraoperatively collected data produced a model with weak predictive capacity for prolonged ventilation [area under curve (AUC) 73.22 and 71.08, respectively]. The use of TISS and SAPS postoperatively resulted in an effective model of prediction (AUC 93.76). Adding the occurrence of reoperation, reintubation, emergency transfusion, intraaortic balloon pumping, and need for total parenteral nutrition to the model further improved its predictive capacity (AUC 94.74).

CONCLUSIONS

The present results strongly suggest that data collected postoperatively using established scoring systems as well as documented events of high clinical impact for risk assessment and quality control are reliable predictors of prolonged ventilation.

Differential performance among LDH-B genotypes in Rana lessonae tadpoles

The European pool frog, Rana lessonae, is widely polymorphic for two common alleles (b,e) at the lactate dehydrogenase-B (LDH-B) locus. We compared fitness-related larval life-history traits among LDH-B genotypes, which originated from segregation in heterozygous parents, in an artificial pond experiment where tadpoles of R. lessonae from a Swiss population were raised together with tadpoles of the hemiclonal hybrid R. esculenta at two densities. In R. lessonae, LDH-B e/e homozygotes at each density had a higher proportion of metamorphs among survivors, reached metamorphosis earlier, and were heavier at metamorphosis than b/b homozygotes; b/e heterozygotes had intermediate values. That e/e individuals were superior to b/b in both time to and mass at metamorphosis is surprising because these two life-history traits are thought to reflect a performance trade-off; e/e genotypes apparently compensated for shorter time to metamorphosis by a higher growth rate. The two alleles showed the same performance ranking when combined in hybrids with a R. ridibunda allele: When R. esculenta from Swiss populations reared in the same ponds had received the e allele rather than the b allele from their R. lessonae parent, they reached metamorphosis earlier, but did not differ in mass at metamorphosis. The degree of linkage disequilibrium in the source population of the eight R. lessonae used as parents of the R. lessonae tadpoles is unknown, so we cannot exclude the possibility that the performance differences are caused by some anonymous tightly linked gene, rather than the LDH-B locus, that constitutes the genomically localized target of natural selection. A causal involvement of LDH-B is plausible, nevertheless, because this enzyme takes part in the central energy-metabolizing processes and has been reported to underlie fitness differences in other animals; also, differential performance of LDH-B genotypes has been observed in R. lessonae larvae from another population. The present results suggest strong directional selection for allele e; the sum of available data, including an independent laboratory experiment, suggests that partial environment-dependent overdominance combined with balancing selection favoring e/e homozygotes under some and b/b homozygotes under other conditions may be partially responsible for the broad maintenance of the LDH-B polymorphism in R. lessonae.

Spontaneous heterosis in larval life-history traits of hemiclonal frog hybrids

European water frog hybrids Rana esculenta (Rana ridibunda x Rana lessonae) reproduce hemiclonally, transmitting only their ridibunda genome to gametes. We compared fitness-related larval life-history traits of natural R. esculenta from Poland with those of the two sympatric parental species and of newly generated F1 hybrids. Compared with either parental species, F1 hybrid offspring had higher survival, higher early growth rates, a more advanced developmental stage by day 49, and earlier metamorphosis, but similar mass at metamorphosis. R. esculenta from natural lineages had trait values intermediate between those of F1 offspring and of the two parental species. The data support earlier observations on natural R. esculenta that had faster larval growth, earlier metamorphosis, and higher resistance to hypoxic conditions compared with either parental species. Observing larval heterosis in F1 hybrids in survival, growth rate, and time to metamorphosis, however, at an even higher degree than in hybrids from natural lineages, demonstrates that heterosis is spontaneous and results from hybridity per se rather than from subsequent interclonal selection; in natural lineages the effects of hybridity and of clonal history are confounded. This is compelling evidence for spontaneous heterosis in hybrid clonals. Results on hemiclonal fish hybrids (Poeciliopsis) showed no spontaneous heterosis; thus, our frog data are not applicable to all hybrid clonals. Our data do show, however, that heterosis is an important potential source for the extensively observed ecological success of hybrid clonals. We suggest that heterosis and interclonal selection together shape fitness of natural R. esculenta lineages.

Results after partial left ventriculectomy in a European heart failure population

BACKGROUND

Forty-nine consecutive patients undergoing partial left ventriculectomy (Batista) surgery between January 1995 and June 1998 were studied.

METHODS

Patient ages ranged from 12 to 85 years, and all patients were in New York Heart Association functional Class III or IV. Thirty-three patients had ischemic cardiomyopathy, and 16 had idiopathic myopathy. Inclusion criteria were left ventricular end diastolic volume index of > 150 mL/m2, left ventricular ejection fraction of < 20%, or left ventricular end-diastolic diameter of > 70 mm. Sixteen patients were transplant candidates. Partial left ventriculectomy and mitral valve repair by means of a Cosgrove annuloplasty ring plus the Alfieri repair constituted only part of the complex cardiac reconstruction in 38 patients.

RESULTS

Five patients died early and five patients died late between 3 and 30 months postoperatively. The actuarial 1-year survival rate was 81%. Twenty-seven patients with coronary artery disease underwent one to five bypass grafts when appropriate. In addition, three patients received aortic valve replacement, four received tricuspid valve repair, two received mitral valve replacement, and two underwent dynamic cardiomyoplasty. Left ventricular (LV) diameter could be reduced from a preoperative mean of 71 to 56 mm postoperatively. LV ejection fraction increased to 36% postoperatively. Ninety percent of patients are in New York Heart Association functional Class I or II.

CONCLUSIONS

Patients with end-stage idiopathic or ischemic cardiomyopathies can be improved considerably with partial left ventriculectomy. Any cardiac comorbidity should be repaired simultaneously.

Pediatric circulatory support

BACKGROUND

Mechanical circulatory support in infants and small children is still a crucial issue. Until recently technological advances have been limited to the adult population.

METHODS

Between February 1994 and December 1996, 553 infants or children underwent operation at our institution. Ten of them were treated with cardiac assist systems. Their ages ranged from 4 days to 8 years (median 5 months). In 8 patients we used a pulsatile circulatory support system available in 6 sizes (9, 10, 22.5, 25, 54, and 60 mL). A centrifugal pump was used in 2 additional infants. In 3 children cardiac assist was considered as a bridge to transplantation; in the remaining patients postcardiotomy failure or cardiogenic shock led to mechanical support.

RESULTS

Median duration of assist was 4 days (range 8 hours to 17 days). In all cases we could observe recovery of renal, hepatic, and cardiac function in the immediate postimplantation period. Six patients survived and could be discharged either after successful transplantation or after myocardial recovery from postcardiotomy failure. The cause of death in 4 cases was bleeding and multiorgan failure. No technical failures occurred with either system.

CONCLUSIONS

The pulsatile circulatory support system seems to be feasible and effective for pediatric extracorporeal support. If the anatomic situation does not permit implantation, centrifugal pumps are an alternative.

Retinoic acid receptor alpha mediates growth inhibition by retinoids in rat pancreatic carcinoma DSL-6A/C1 cells

During carcinogenesis, pancreatic acinar cells can dedifferentiate into ductal adenocarcinoma of the pancreas. DSL-6A/C1 cells represent an in vitro model of this carcinogenic sequence. This study was designed to examine the effects of retinoids on cell growth in DSL-6A/C1 cells and to characterize further the molecular mechanisms underlying the antiproliferative actions of retinoids. Treatment of DSL-6A/C1 cells with retinoids results in a time- and dose-dependent inhibition of cell growth, paralleled by a retinoid-mediated transactivation of a pTK::betaRAREx2-luciferase reporter construct transiently transfected into DSL-6A/C1 cells. Retinoid receptor expression was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) using subtype-specific primers and demonstrated expression of retinoic acid receptor alpha (RAR-alpha), RAR-beta and retinoid X receptor alpha (RXR-alpha). Using a panel of receptor subtype-specific agonists, the RAR-alpha specific agonist Ro 40-6055 was the most potent retinoid in terms of growth inhibition. Furthermore, all-trans-retinoic acid-mediated growth inhibition and transactivation was completely blocked by the RAR-alpha-specific antagonist Ro 41-5253. In summary, the RAR-alpha subtype predominantly mediates the antiproliferative effects of retinoids in DSL-6A/C1 cells. Furthermore, this cell system provides a feasible tool to study the molecular mechanisms underlying the growth inhibitory effects of retinoids in ductal pancreatic carcinoma cells derived from a primary acinar cell phenotype.

Effect of different immunosuppressive agents on acute pancreatitis: a comparative study in an improved animal model

BACKGROUND

Immunosuppressive drugs have been associated with the development and progression of acute pancreatitis after organ transplantation. Consequently, a reduction or a change in immunosuppressive therapy has been recommended once posttransplantation pancreatitis has been suspected. However, it is not known which of the available immunosuppressive agents is most harmful to the pancreas and which may be used safely in this situation. The objective of this study was to investigate the effect of different immunosuppressive drugs in various dosages on intrapancreatic protease activation, acinar cell necrosis, and mortality in an improved model of acute necrotizing pancreatitis in the rat. The rat model of acute necrotizing pancreatitis, like posttransplantation pancreatitis, is characterized by ischemia and microcirculatory disorders.

METHOD

Acute pancreatitis was induced in rats by using a combination of low-dose controlled intraductal glycodeoxycholic acid superimposed on intravenous cerulein hyperstimulation. Six hours thereafter, animals were randomized to intravenous therapy with 2, 10, or 50 mg/kg/day prednisolone (PRED); 3, 15, or 60 mg/kg/day cyclosporine A (CsA); 10 mg/kg/day azathioprine (AZA); 0.6 mg/kg/day orthoclone OKT3 (OKT3); or saline. After 36 hr, surviving animals were killed to determine acinar cell necrosis and trypsinogen activation peptides levels (TAP) in blood and ascites.

RESULTS

Compared with saline-treated control rats, animals treated with 60 mg/kg/day CsA developed significantly more acinar cell necrosis and had increased amounts of TAP in ascites. Likewise, there was more extensive acinar cell necrosis in animals subjected to AZA therapy. However, this was not associated with incremental TAP. Animals treated with 3 or 15 mg/kg/day CsA, OKT3, or PRED showed no significant changes in these target parameters. Animals given 10 or 50 mg/kg/day PRED even had decreased hematocrit values and produced significantly less ascites than animals in the other groups.

CONCLUSION

The present results suggest that AZA and high doses of CsA aggravate acute pancreatitis and should, therefore, be avoided once posttransplantation pancreatitis has been suspected, whereas lower doses of CsA, OKT3, and PRED may be used safely. PRED can even be used at higher doses as may be required when graft rejection is suspected.

Genomes of two water frog species resist germ line exclusion in interspecies hybrids

Abundant natural interspecies hybrids between the European water frog Rana ridibunda and at least three other taxa reproduce hemiclonally, by hybridogenesis: the non-ridibunda genome is excluded in the germ line before meiosis, and the unrecombined ridibunda genome is transmitted to haploid gametes. In contrast, natural hybrids between Rana ridibunda and either of two Balkan species (Rana shqiperica and Rana epeirotica) do not show such genome exclusion. This plausibly results from failure of Balkan Rana ridibunda genomes to "induce" such exclusion in the germ line of hybrids, from "resistance" of Rana shqiperica and Rana epeirotica genomes to such exclusion in hybrids with an "inducing" Rana ridibunda genome, or both. We tested the second hypothesis by examining lampbrush chromosome patterns in oocytes of hybrids that in the soma contain one "inducing" ridibunda genome and one genome of either of the two Balkan species. Several lampbrush chromosome markers (e.g., presence and location of certain giant loops and conspicuousness and width of centromeres) discriminate sets of Rana ridibunda chromosomes from those of Rana shqiperica and Rana epeirotica. Based on such markers, nine diploid female hybrids between Rana ridibunda or Rana esculenta from natural hybridogenetic lineages (Rana ridibunda x Rana lessonae, making ridibunda gametes) from central Poland and either Rana shqiperica or Rana epeirotica each contained both parental genomes in primary oocytes; the bivalents showed reduced numbers of chiasmata compared with parental species. It follows that none of these hybrids was hybridogenetic. This conclusion is confirmed, for two hybrids between Rana epeirotica and either Rana ridibunda or Rana esculenta, by protein electrophoretic comparison of somatic tissues with primary oocytes, all of which evidenced allelic markers of both parental species. Because Rana ridibunda genomes that are known to induce germ line genome exclusion when combined in hybrids with Rana lessonae genomes were used, these data provide the first compelling evidence for resistance of Rana shqiperica as well as Rana epeirotica genomes to such exclusion.

Taxon composition and genetic variation of water frogs in the Mid-Rhône floodplain

Natural hemiclonal hybrid lineages of water frogs reproduce by hybridogenesis, excluding one parental genome in the germ line and mating with the coexisting same parental species. Two such sexual host-hybridogen systems occur in the Rhône valley: the L-E system in the north, the P-G system in the south. Although these hybridogenetic complexes may overlap along the Rhône river, there is no evidence for a contact zone in our samples: only Rana ridibunda and R. esculenta were identified using protein electrophoresis. Whether the absence of R. perezi reflects a more southern distribution or its exclusive occurrence in other habitats, remains to be tested. Comparison of somatic and gonadal tissues reveals that gametogenesis of R. esculenta is of the L-E type: gametes carry ridibunda genomes. R. ridibunda apparently is not native, but was introduced by humans, and the R. esculenta in our samples is probably an immigrant from nearby L-E systems.

Linkage groups of protein-coding genes in western palearctic water frogs reveal extensive evolutionary conservation

Among progeny of a hybrid (Rana shqiperica x R. lessonae) x R. lessonae, 14 of 22 loci form four linkage groups (LGs): (1) mitochondrial aspartate aminotransferase, carbonate dehydratase-2, esterase 4, peptidase D; (2) mannosephosphate isomerase, lactate dehydrogenase-B, sex, hexokinase-1, peptidase B; (3) albumin, fructose-biphosphatase-1, guanine deaminase; (4) mitochondrial superoxide dismutase, cytosolic malic enzyme, xanthine oxidase. Fructose-biphosphate aldolase-2 and cytosolic aspartate aminotransferase possibly form a fifth LG. Mitochondrial aconitate hydratase, alpha-glucosidase, glyceraldehyde-3-phosphate dehydrogenase, phosphogluconate dehydrogenase, and phosphoglucomutase-2 are unlinked to other loci. All testable linkages (among eight loci of LGs 1, 2, 3, and 4) are shared with eastern palearctic water frogs. Including published data, 44 protein loci can be assigned to 10 of the 13 chromosomes in Holarctic Rana. Of testable pairs among 18 protein loci, agreement between Palearctic and Nearctic Rana is complete (125 unlinked, 14 linked pairs among 14 loci of five syntenies), and Holarctic Rana and Xenopus laevis are highly concordant (125 shared nonlinkages, 13 shared linkages, three differences). Several Rana syntenies occur in mammals and fish. Many syntenies apparently have persisted for 60-140 x 10(6) years (frogs), some even for 350-400 x 10(6) years (mammals and teleosts).

Stentless porcine bioprostheses for all types of aortic root pathology

OBJECTIVE

Conventional biological and mechanical prostheses have important limitations with regard to their results concerning thrombosis, hemorrhage and long-term durability. Aortic valve replacement with stentless devices results in superior hemodynamic function because obstructing stents and sewing rims are avoided. In addition, no anticoagulation therapy is needed.

METHODS

From 1 June 1991 until 31 May 1996, 235 patients received aortic valve replacement with stentless aortic porcine bioprostheses. Patients' ages ranged from 24 to 88 years (mean 64 years). In 21.3% of all patients, concomitant procedures were performed. Coronary artery bypass graft (CABG) and mitral valve surgical therapy were the most frequent ones (31 and 12 cases, respectively). Implanted valve sizes ranged from 21 to 29 mm in diameter.

RESULTS

A total of 122 patients received a subcoronary implantation with the lower row performed with interrupted stitches and the upper row with a continuous suture. In 99 cases we performed the inclusion cylinder technique, also with lower interrupted sutures and running upper sutures after adaptation of the coronary ostia into the graft. In the group with small aortic roots, the total root replacement technique (n = 14) was used. Mortality at 30 days was 4.7% (11/235). Echocardiography at discharge postoperatively revealed a mean gradient across the prosthesis of 6 mm Hg. Color Doppler suggested no or trivial regurgitation in 93% of all examined patients and mild regurgitation without clinical symptoms in 7%. Up to now, 98.2% of all discharged patients have been free of valve-related reoperation.

CONCLUSIONS

With implantation of stentless bioprostheses, an improved hemodynamic function will be obtained. Almost every aortic root pathology can be safely treated with any of the techniques described. The short and intermediate results seem to be at least equal to any other prostheses or treatment methods. The long-term performance of these devices is still under investigation.

Clinical experience with the MEDOS HIA-VAD system in infants and children: a preliminary report

BACKGROUND

The need of pediatric cardiac assist is growing because of the complexity of the congenital conditions operated on and the increasing number of pediatric transplantations. We evaluated the newly developed pediatric MEDOS HIA-VAD ventricular assist device.

METHODS

The pneumatic paracorporeal ventricular assist device has three left ventricular sizes (10-, 25-, and 60-mL maximum stroke volume) and three right ventricular sizes (9, 22.5, and 54 mL) and can be operated effectively with up to 180 cycles/min. We used this device in 6 consecutive pediatric patients. Intention of treatment was to bridge to transplantation in 3 patients and to aid in recovery from a cardiac operation in 3. Age ranged from 5 days to 8 years.

RESULTS

Two children died during assist, 2 were weaned from the system and discharged home, and 2 had successful transplantation. During assist, laboratory variables indicative of impaired renal, hepatic, or pulmonary function normalized or showed a trend toward normalization. Both deaths were related to infection.

CONCLUSIONS

With the new MEDOS HIA-VAD ventricular assist device system, pediatric mechanical cardiac assist can be performed successfully. It requires timely implantation, careful monitoring, and adequate size-matched devices.

Mitral valve reconstruction and mitral valve replacement for ischemic mitral insufficiency

BACKGROUND

Patients with ischemic mitral incompetence have a high operative risk whether the valve is repaired or replaced. The advantage of repair over replacement is unclear in this group of patients.

METHODS

Between April 1986 and December 1994, 232 patients underwent surgery for ischemic mitral valve insufficiency; mitral valve replacement was performed in 98 of them. Operative mortality was 13.3%. The actuarial survival rate after 5 years was 73.3%. The surgical risk in patients whose left ventricular ejection fraction (LVEF) was 10%-30% (operative mortality 50.0%) was higher than in those whose LVEF was greater than 30%. Valve reconstruction was performed in 102 patients. Operative mortality in this patient group was 14.7%. The surgical risk in patients whose LVEF was < or = 30% was higher (operative mortality 42.9%).

RESULTS

The total actuarial survival rate of all patients was 64.4% after 5 years. Mortality during follow-up was higher in patients with residual mitral valve insufficiency greater than grade I after mitral valve reconstruction. Twenty-four patients with severely impaired left ventricular function underwent heart transplantation. Operative mortality in this group was 12.5%. Eight patients received left ventricular aneurysmectomy in addition to valve surgery, three of them died early.

CONCLUSIONS

We conclude that patients with highly impaired left ventricular function and ischemic mitral insufficiency are at too great a risk for either valve reconstruction or replacement. Cardiac transplantation should be considered for this patient group. However, patients with ischemic mitral insufficiency and moderately impaired left ventricular function can undergo valve reconstruction or replacement with an acceptable prognosis. The goal of mitral valve reconstruction should be reducing mitral valve insufficiency to at least grade I. If this is not achieved, the prognosis after repair is worse than after valve replacement, therefore, the surgeon should replace the valve without delay.

Ross operation and right ventricular outflow tract reconstruction with stentless xenografts

Traditionally a homograft valve is used as a pulmonary replacement device for the Ross operation. Right ventricular outflow tract reconstruction during aortic valve replacement with an autograft was performed with stentless xenograft valves in nine patients. Hemodynamic performance is satisfying, but, long term evaluation is needed.

[Surgical coronary revascularization of the beating heart]

Despite the fact that all the progress in technology, surgical technique and pathophysiological knowledge has made aortocoronary bypass surgery a safe routine procedure, there are certain clinical settings where an alternative approach seems to be advantageous. In 50 patients with age ranging from 51 to 74 years with advanced coronary heart disease and poor left ventricular (LV) function, as well as in patients with good LV function and single or double vessel disease not amenable for PTCA and in patients with acute ischemia or recent myocardial infarction, we performed coronary artery bypass grafting (CABG) without cardioplegic arrest during a short period of left ventricular unloading by means of a left ventricular assist device (LVAD). During LVAD support we administered Esmolol to decrease the heart rate and to keep the heart flaccid to facilitate easier peripheral anastomosis on a breathing heart. Preoperative ejection fraction ranged from 15 to 56%. In two patients of the acute MI-group, we continued the left ventricular mechanical support postoperatively, one of them survived. We performed on average 1,4 distal anastomoses and used in 34 cases the left internal mammary artery. All but three patients survived the procedure in stable conditions and could leave intensive care after a mean stay of 1.5 days. There were no perioperative myocardial infarctions. In our view, CABG during LVAD support without heart lung machine and cardioplegia is a safe and life saving procedure. No ischemic damage is applied to the heart and it can be recommended for cautions use in select patients.

Molecular characterization of a centromeric satellite DNA in the hemiclonal hybrid frog Rana esculenta and its parental species

Hybrid water frogs Rana esculenta reproduce by hybridogenesis: one parental genome (of Rana lessonae) is excluded in the germ line, the other (of Rana ridibunda) is clonally transmitted to haploid gametes. The two parental species differ in that the amount of centromeric heterochromatin revealed by differential staining is much higher in Rana ridibunda. An abundant, tandemly arrayed, centromeric satellite DNA, designated RrS1, is revealed in Rana ridibunda genomes by the restriction endonuclease Stul, which generates a major repetitive sequence fragment of 300 and a minor one of 200 bp. This AT-rich (68%) satellite family is located at the centromeres of the five largest chromosomes (1-5) and of a medium to small heterobrachial one (8 or 9); it thus constitutes only part of the centromeric heterochromatin that characterizes all Rana ridibunda chromosomes. RrS1 represents about 2.5% of the genome of Rana ridibunda; it may represent as little as 0.2% of the genome of Rana lessonae, and cannot be detected in Xenopus laevis frogs or Salamandra salamandra and Triturus carnifex salamanders. Segments of the satellite sequence are similar to sequences of yeast centromeric DNA element CDEIII and of the mammalian CENP-B box. A role for RrS1 and other centromeric satellite DNAs in the germ line genome exclusion of the hybridogenetic frog hybrids, although suggested, has not yet been demonstrated.

Presynaptic opioid receptors on dopaminergic nerves in the rabbit caudate nucleus: coupling to pertussis toxin-sensitive G-proteins and interaction with D2 autoreceptors?

Slices of the rabbit caudate nucleus, preincubated with [3H]dopamine and subjected to electrical field stimulation, were used (1) to investigate the involvement of G-proteins in the signal transduction of presynaptic D2 (auto)receptors and kappa-opioid receptors on dopaminergic axon terminals in this tissue and (2) to study a possible mutual interaction of these two presynaptic receptors. Pretreatment of the slices with either pertussis toxin (8 micrograms/ml; 18 h), or N-ethylmaleimide (30 microM, 30 min) significantly reduced the inhibitory effects of both the D2 agonist quinpirole and the kappa-opioid receptor agonist U-50488H on the [3H]overflow evoked by 36 pulses (2 ms, 24 mA, 0.3 Hz), suggesting the coupling of both receptors to G-proteins. Experiments designed to study possible interactions of these two presynaptic receptors were carried out under stimulation conditions (only 1 pulse), which strongly diminish interference of endogenous transmitters released in the tissue with modulatory effects of exogenous drugs. For instance, due to the presence of endogenous dopamine, quinpirole was much less potent during 36-pulse-than during 1-pulse field stimulation, whereas the D2 antagonist domperidone was almost without effect in the latter case. Using the 1-pulse stimulation paradigm, the concentration/response curve of quinpirole was unaffected in the presence of the half-maximal inhibitory concentration of U-50,488 H (0.1 microM). On the other hand, also quinpirole at its half-maximal inhibitory concentration (0.1 microM), hardly affected the concentration/response curve of U-50,488 H: only high concentrations of U-50,488 H (above 1 microM) seemed to be slightly less effective in the presence than in the absence of the D2 agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

No evidence for presynaptic opioid receptors on cholinergic, but presence of kappa-receptors on dopaminergic neurons in the rabbit caudate nucleus: involvement of endogenous opioids

The effects of various opioid receptor agonists and antagonists were studied in rabbit caudate nucleus slices preincubated with either [3H]dopamine or [3H]choline, superfused with medium (containing in most experiments the D2 receptor antagonist domperidone) and subjected to electrical field stimulation. The stimulation-evoked [3H]overflow from slices prelabeled with [3H]dopamine (evoked [3H]dopamine release) was significantly reduced by preferential kappa-opioid receptor agonists, like U-50,488 H, but not by mu- or delta-opioid receptor selective drugs. Opioid receptor antagonists shifted the concentration/response curve of U-50,488 H to the right (apparent pA2-value of the kappa-selective antagonist nor-binaltorphimine: 10.1) and enhanced the evoked dopamine release in the presence of a mixture of peptidase inhibitors. On the other hand, the [3H]overflow from rabbit caudate nucleus slices prelabeled with [3H]choline (evoked acetylcholine release) remained almost unaffected by any opioid receptor agonist, as long as the presynaptic D2 heteroreceptor was blocked with domperidone: in the absence of domperidone, U-50,488 H exhibited facilitatory effects. For comparison, the effects of the preferential delta-opioid receptor agonist DPDPE was also studied in slices of the rat striatum, where it clearly inhibited the evoked acetylcholine release. From our data we conclude that in the rabbit caudate nucleus the evoked dopamine release is inhibited by both exogenous and endogenous opioids via presynaptic kappa-opioid receptors, whereas the evoked release of acetylcholine is not, or only indirectly (via released dopamine) affected by opioids.

Mitochondrial DNA reveals formation of nonhybrid frogs by natural matings between hemiclonal hybrids

The European water frog Rana esculenta (RL), a natural hybrid between R. ridibunda (RR) and R. lessonae (LL), reproduces by hybridogenesis: haploid gametes usually contain an intact chromosome set of R. ridibunda (R); the lessonae nuclear genome (L) is lost from the germ line. Hybridity is restored in the next generation, via fertilization by syntopic R. lessonae. Matings between two hybrids (RL x RL) usually give inviable R. ridibunda (RR) progeny. The adult R. ridibunda subpopulation of Trubeschloo, a gravel pit in northern Switzerland, consists only of females. Fragment patterns for mitochondrial DNA (mtDNA) of these R. ridibunda were identical with those of syntopic R. esculenta and of local populations of R. lessonae; they differed from the patterns in eastern European populations of R. lessonae and of R. ridibunda mtDNAs (3.7% and 9.3% estimated sequence divergence, respectively). In contrast, mtDNAs of two R. ridibunda from an introduced Swiss population with both sexes, although different (2.7% divergence) from each other, were typical R. ridibunda rather than R. lessonae mtDNAs. These data, together with unisexuality, demonstrate conclusively that the all-female R. ridibunda population at Trubeschloo originated from matings between two R. esculenta. The formation of independently reproducing R. ridibunda populations via such hybrid x hybrid matings is precluded because progeny of these matings are unisexual. Recombination in the regenerated fertile R. ridibunda females, followed by matings with R. lessonae, nevertheless provides a mechanism for meiotic reshuffling of genetic material in ridibunda haplotypes that is not typically available in hemiclonal lineages.

Lampbrush and mitotic chromosomes of the hemiclonally reproducing hybrid Rana esculenta and its parental species

Mitotic chromosomes of the European water frogs Rana ridibunda and Rana lessonae, the parental species of Rana esculenta, differ significantly in their centromeric regions: when C-banded or when made fluorescent, the centromeres of R. ridibunda (and of ridibunda chromosomes in R. esculenta) are visible as a conspicuous dark granule or as a conspicuous fluorescent spot; the centromeres of R. lessonae (and of the lessonae chromosomes in R. esculenta) are inconspicuous or not fluorescent. Lampbrush chromosomes of these three taxa are described in detail for the first time; those of R. ridibunda and R. lessonae differ significantly in morphostructural characters such as conspicuousness of centromeres and number, form, and location of giant loops as well as in chiasma frequency. Chromosomes of the two parental species can thus be distinguished when present in lampbrush complements of hybrids. Reproduction in both sexes of natural R. esculenta lineages is hemiclonal: only the unrecombined genome of one parental species, usually R. ridibunda, is transmitted to haploid gametes (hybridogenesis). In 18 hybrids from natural populations of Poland, somatic tissues had allodiploid complements with chromosomes from each parental species. In contrast, spermatocytes I of five males and oocytes I of seven of eight females (221 of 222 oocytes) were autodiploid and contained only R. ridibunda chromosomes that formed n bivalents. These 12 hybrids thus were hybridogenetic. A single female hybrid had oocytes I (33 of 34) with genomes of both parental species; they showed various disturbances including tetraploidy, reduced number of chiasmata, and incomplete synapsis resulting in univalents. This individual thus was not hybridogenetic. The irregular lampbrush patterns indicate that such hybrids will have severely reduced fertility and most of their successful gametes will result in allotriploid progeny.

Once a day verapamil in essential hypertension

Pharmacodynamic and therapeutic studies with a new slow release 240 mg verapamil formulation were performed in a total of 73 patients with essential hypertension (WHO I-II, diastolic greater than or equal to 100 mm Hg). Chronic administration of slow release 240 mg verapamil, one or two tablets in the morning, resulted in 24 h plasma concentration profiles with trough levels greater than 40 ng ml-1 in 14 of 16 patients and good 24 h blood pressure control. There was no correlation between plasma verapamil or norverapamil concentration and blood pressure response. Monotherapy with slow release verapamil was well tolerated and resulted in good blood pressure control (less than or equal to 95 mm Hg diastolic) in 46 of the 57 patients. Responses were best in older patients and those with low plasma renin or higher control blood pressure. Slow release 240 mg verapamil given once daily is a simple and effective regimen.