Pike Esox lucius as an emerging model organism for studies in ecology and evolutionary biology: a review.

The pike Esox lucius is a large, long-lived, iteroparous, top- predator fish species with a circumpolar distribution that occupies a broad range of aquatic environments. This study reports on a literature search and demonstrates that the publication rate of E. lucius research increases both in absolute terms and relative to total scientific output, and that the focus of investigation has changed over time from being dominated by studies on physiology and disease to being gradually replaced by studies on ecology and evolution. Esox lucius can be exploited as a model in future research for identifying causes and consequences of phenotypic and genetic variation at the levels of individuals, populations and species as well as for investigating community processes.

Spatial sorting may explain evolutionary dynamics of wing polymorphism in pygmy grasshoppers.

Wing polymorphism in insects provides a good model system for investigating evolutionary dynamics and population divergence in dispersal-enhancing traits. This study investigates the contribution of divergent selection, trade-offs, behaviour and spatial sorting to the evolutionary dynamics of wing polymorphism in the pygmy grasshopper Tetrix subulata (Tetrigidae: Orthoptera). We use data for > 2800 wild-caught individuals from 13 populations and demonstrate that the incidence of the long-winged (macropterous) morph is higher and changes faster between years in disturbed habitats characterized by succession than in stable habitats. Common garden and mother-offspring resemblance studies indicate that variation among populations and families is genetically determined and not influenced to any important degree by developmental plasticity in response to maternal condition, rearing density or individual growth rate. Performance trials show that only the macropterous morph is capable of flight and that propensity to fly differs according to environment. Mark-recapture data reveal no difference in the distance moved between free-ranging long- and short-winged individuals. There is no consistent difference across populations and years in number of hatchlings produced by long- and shorter-winged females. Our findings suggest that the variable frequency of the long-winged morph among and within pygmy grasshopper populations may reflect evolutionary modifications driven by spatial sorting due to phenotype- and habitat type-dependent emigration and immigration.

Relative cardiac expression of growth hormone receptor and insulin-like growth factor-I mRNA in congenital heart disease.

GH may exert direct growth-promoting and metabolic actions on target tissues, but most of its effects are mediated by circulating (endocrine) or local (auto-/paracrine) IGF-I. The GH/IGF-I system has an important role in cardiac development and in maintaining the structure and function of the heart. A subgroup of children with pronounced heart defects will eventually need transplants, owing to congestive heart failure. Since the symptoms are often severe and may progress while waiting for surgery, it is necessary to develop supportive medical treatment. GH has been proposed as a therapeutic agent in adults with heart failure, but to date studies are lacking on children and more information is necessary. We have examined the expression of IGF-I mRNA and GH-receptor (GH-R) mRNA in children undergoing surgery for congenital heart disease. Eighteen children scheduled for open-heart surgery were included in the study. Right auricular biopsies were taken at the time of venous catheterization preceding cardiac bypass. The specimens were analysed using realtime PCR. We were able to show expression of both IGF-I mRNA and GH-R mRNA in the pediatric heart. The relative expressions were intercorrelated (r=0.75, p<0.001). GH-R mRNA correlated positively to standardized weight (r=0.65, p=0.004), body mass index (BMI) (r=0.59, p=0.01), and standardized BMI (r=0.59, p=0.01). IGF-I mRNA only correlated to BMI (r=0.50, p=0.04). This is the first study displaying cardiac expression of IGF-I mRNA and GH-R mRNA in children with congenital heart disease, although further studies are needed to define a role for GH in the treatment of these patients.

The outcome of children born with pulmonary atresia and intact ventricular septum in Sweden from 1980 to 1999.

OBJECTIVE: To study the outcome of all children born with pulmonary atresia and intact ventricular septum in Sweden between 1980 and 1999. DESIGN: Retrospective study of medical records with review of the initial, preoperative angiocardiographic and echocardiographic examinations. RESULTS: A total of 84 children were born with pulmonary atresia and intact ventricular septum, giving an incidence of 4.2 per 100,000 live births. In all, 77 were operated on with a 1-year survival rate of 75%. Thirty-six children had ventriculocoronary communications, with a 1-year survival rate of 50%. At the end of the study period, 52 children were alive, 32 with biventricular repair, and 19 with univentricular repair. Follow-up time was 14 days-20 years (median, 6 years). Statistical analysis of incremental risk factors for death showed statistical significance for low birth weight, male sex, muscular pulmonary atresia, and having a systemic-to-pulmonary shunt as the sole initial intervention. CONCLUSION: Complete national data of all patients born with pulmonary atresia and intact ventricular septum during 1980-1999 in Sweden revealed a total mortality in accordance with previous reports for results for surgery. Further improvements demand a thorough preoperative investigation of the cardiac anatomy, particularly of the ventriculocoronary communications, to enable right ventricular decompression whenever possible.

Clinical variables and pro-inflammatory activation in paediatric heart surgery.

OBJECTIVES: The first aim was to analyse the role of preoperative characteristics and perioperative variables in predicting the inflammatory response during and early after operations for congenital heart malformations of moderate to severe complexity. The second aim was to correlate complement and cytokine activation during the same period with clinical variables reflecting the postoperative course. METHODS: Prospective descriptive clinical study that involved 22 consecutive children (1-28 months). Five children had Down's syndrome. Concentrations of C3a, C5b-9 and IL-6 were measured. RESULTS: C3a, C5b-9 and IL-6 increased significantly during the study period (ANOVA: C3a, p = 0.001; C5b-9, p = 0; IL-6, p = 0). C3a correlated with preoperative haemoglobin (r = 0.71, p = 0.0002) and CPB time (r = 0.72, p=0.0005). C5b-9 correlated with CPB time (r= 0.58, p=0.004). IL-6 related to presence of Down's syndrome (p=0.0001) and correlated with preoperative haemoglobin (r=0.55, p=0.02), preoperative weight deviation (r = -0.52, p = 0.03) and time in the ventilator (r = 0.68, p = 0.002). CONCLUSIONS: Preoperative and perioperative characteristics predict the inflammatory response during open heart surgery in infants and small children. IL-6 response is related to the postoperative course.

Reversal of protein-losing enteropathy in a child with Fontan circulation is correlated with central venous pressure after heart transplantation.

We report on the reversal of protein-losing enteropathy (PLE) after heart transplantation (HTx) in a 10-yr-old boy with Fontan circulation, previously treated unsuccessfully with heparin for several months. The protein loss continued immediately after the Tx. During the following month, however, a gradual decrease in protein loss was observed, which correlated with a decrease in the inferior vena cava (IVC) pressure. The patient is doing well with a normal serum albumin level and a normal IVC pressure, 2 yr after Tx.

Thoracic organ transplantation in children. The Sahlgrenska University Hospital experience.

On the basis of the experience acquired from more than 350 thoracic organ transplantations in adults, the outcome of thoracic organ transplantations in the paediatric age group (0-17 years of age) performed consecutively from 1989 to 1998 at our centre was reviewed. Heart transplantation was performed in 27 patients, heart-lung in 6 and bilateral lung transplantation in 2 patients. The preoperative diagnosis included dilated cardiomyopathy in 17 patients, congenital heart defects in 8, hypertrophic cardiomyopathy in 2, cystic fibrosis in 1 and secondary and primary pulmonary hypertension in 5 and 2 patients, respectively. The median age at transplantation and the follow-up period were 12.7, range 0.3-18.2, and 4, range 0.1-9.2 years, respectively. No early deaths occurred after heart transplantation, but one patient died of coronary artery disease 4.8 years after transplantation. One early death occurred one week after heart-lung transplantation as a result of bleeding complications, and another patient died of obliterative bronchiolitis and pulmonary infection 2.5 years after surgery. The remaining patients are alive and have been functionally rehabilitated. In conclusion, despite a relatively small centre volume, paediatric thoracic organ transplantations can be performed with good short- and medium-term survival and good functional status can be achieved by deriving knowledge and experience from transplantations in adults and by collaboration between the various professionals involved in the caring process.

Centralization of pediatric heart surgery in Sweden.

In Sweden, which has a population of 8.9 million people, pediatric heart surgery was previously performed in four cities. After a long, difficult process, centralization of pediatric heart surgery to two centers was achieved in 1993. The overall 30-day mortality for open-heart surgery on infants and children of 9.5% before the centralization (1988-1991) was reduced to 1.9% in 1995-1997. A causal relationship between the mortality rates before and after the centralization is impossible to prove. Heart surgery was concentrated to the two centers with the lowest surgical mortality, and the reduction in surgical mortality was observed over a short period of time which makes it likely that the centralization of the surgical activity promoted the improved results. During the later time period the amount of more complex surgery was clearly increased compared to that performed previously.

Increased levels of S-100 protein after cardiac surgery with cardiopulmonary bypass and general surgery in children.

The aim of this study was to evaluate changes in concentrations of the neurospecific protein S-100 in relation to cardiac surgery with cardiopulmonary bypass (CPB) and noncardiac general surgery in children below 3 years of age. Seventeen children underwent surgery for congenital heart disease and all survived without clinical signs of neurological complications. Samples for plasma concentrations of S-100 in these patients were taken on three occasions in connection with surgery: before the start of surgery, after CPB and finally 16-20 h after CPB. In the noncardiac group of 31 children, S-100 concentrations were measured on two occasions: before surgery and during surgery. In both groups, a significant increase in S-100 concentrations was observed during surgery, although the increase in the CPB group was significantly higher than in the noncardiac group. The CPB group included four children with Down's syndrome who had higher mean S-100 concentrations on all sampling occasions compared to the remaining patients. The peak S-100 concentrations after cardiac surgery were related to the duration of CPB, the time from the termination of CPB to the first post-CPB sample, as well as mean arterial pressure and cerebral arteriovenous lactate difference during rewarming. All the children studied (Down's patients excluded) had age-dependent plasma concentrations of S-100 measured before surgery. It can be concluded that CPB initiates a marked but transient release of S-100 into the systemic circulation during open heart surgery in children who are not developing clinical signs of neurological sequelae.

Preoperative evaluation and surgery in isolated ventricular septal defects: a 21 year perspective.

OBJECTIVE: To study short and long term results after surgical closure of isolated ventricular septal defects (VSDs) from 1976 to 1996, especially in relation to changes in preoperative evaluation during this period. DESIGN: Retrospective study. SETTING: Tertiary referral centre for paediatric cardiac care. PATIENTS: All children under 18 years of age who had corrective surgery for VSD between 1976 and 1996. MAIN OUTCOME MEASURES: Preoperative evaluation, indications for surgery, diagnostic errors, and early and late results. RESULTS: A significant decrease in the use of invasive preoperative studies in favour of non-invasive methods was found; from 1976 to 1990, a total of 109/110 patients had preoperative invasive study as compared to 43/167 from 1991 to 1996 (p < 0.001). Pulmonary hypertension in small children, without detailed information on Qp:Qs ratio, as well as small or modest shunts without pulmonary hypertension, were more frequent indications for surgery in recent years. Early mortality after surgery occurred in 10 patients, with a significantly lower mortality rate found between 1991 and 1996 than between 1976 and 1990 (0.6% v 8.2%, p < 0.001). Children with large VSDs experienced perioperative complications significantly less often between 1991 and 1996 than between 1976 and 1990 (16/105 v 28/96, p < 0.05). Diagnostic errors showed a tendency to decrease between the two time periods. No late deaths occurred. CONCLUSIONS: Significant reductions in early mortality, perioperative complications, and diagnostic mistakes were seen during the study period, even though less invasive diagnostic procedures were being performed.

Long-term Doppler echocardiographic results of aortic or mitral valve replacement with Biocor porcine bioprosthesis.

OBJECTIVES: Our objectives were to evaluate the long-term bioprosthetic and cardiac functional outcome after insertion (over a 10-year period) of a new-generation porcine zero pressure-fixed Biocor bioprosthesis, as well as to determine the echocardiographic accuracy for selection of patients requiring reoperation. The long-term systematic Doppler echocardiographic assessment after valve replacement with this bioprosthesis is lacking. METHODS: Between January 1983 and January 1993, we inserted 756 Biocor prostheses in the aortic (619) or mitral (137) positions. All 51 patients who had a reoperation during the follow-up time were evaluated echocardiographically before reoperation. Additionally, 263 of 446 patients (59%) with aortic bioprostheses and 42 of 74 patients (57%) with mitral bioprostheses who were alive in January 1993 had long-term echocardiographic follow-up. RESULTS: Group A: Normally functioning bioprostheses were found in the aortic position in 242 of 263 patients and in the mitral position in 33 of 42 patients. Group B: Thirty patients had abnormal bioprosthetic function. Eleven patients had regurgitation, 3 had a combined lesion, and signs of calcification appeared in 16 patients with aortic valves, all with a peak gradient of above 60 mm Hg. Group C: Patients who had a reoperation (41 aortic and 10 mitral) within the follow-up period were followed up echocardiographically from the detection of a possible valve dysfunction until reoperation, and the findings accorded well with those at operation in 49 of 51 patients. CONCLUSIONS: These findings suggest that, during a long-term follow-up, most bioprostheses function normally, facilitating improved heart function. Abnormalities in a bioprosthesis usually develop gradually, enabling their detection by Doppler echocardiographic evaluations performed regularly or in case of any symptomatic deterioration.

Predictors for recurrent chest pain and relationship to myocardial ischaemia during long-term follow-up after coronary artery bypass grafting.

OBJECTIVE: To describe the impact of coronary artery bypass grafting on chest pain during 2 years of follow-up after the operation and to identify predictors of chest pain and its relationship to myocardial ischaemia 2 years after the operation. METHODS: Patients were approached with a questionnaire at the time of coronary angiography (1291) and 3 months (1664), 1 year (1638) and 2 years (1613) after coronary artery bypass grafting. Two years after the operation, a computerised 12-lead electrocardiogram was obtained during a standardised bicycle exercise test (618). RESULTS: Prior to surgery, 37% of the patients were unable to perform physical activity compared with 6% after the operation (P < 0.0001 for change in degree of limitation). Only 3% had no chest pain at all prior to the operation, while 58% of the patients were free from chest pain 2 years after surgery (P < 0.0001). We found no correlation between patients reporting chest pain and signs of ischaemia at exercise test, but there was a highly significant correlation with chest pain during the exercise test (P < 0.0001). Independent predictors of chest pain were severity of preoperative angina (P < 0.0001), younger age (P = 0.0009), previous coronary artery bypass grafting (P = 0.003), duration of symptoms (P = 0.005), the need for prolonged cardiopulmonary bypass (P = 0.04) and the absence of left main stenosis (P = 0.04). CONCLUSION: Independent predictors of chest pain were identified 2 years after coronary artery bypass grafting. There was a dramatic improvement after coronary artery bypass grafting. However, almost half the patients complained of some kind of chest pain even after the operation. This chest pain correlated well with chest pain during the exercise test but not with signs of myocardial ischaemia.

Female sex is associated with increased mortality and morbidity early, but not late, after coronary artery bypass grafting.

OBJECTIVE: To describe mortality and morbidity during a period of 2 years after coronary artery bypass grafting in relation to gender. DESIGN: Prospective follow-up study. SETTING: Two regional cardiothoracic centres which performed all the coronary artery bypass operations in western Sweden at the time. SUBJECTS: A total of 2129 (1727 (81%) men and 402 (19%) women) consecutive patients undergoing coronary artery bypass surgery between June 1988 and June 1991 without concomitant procedures. RESULTS: Females were older and more frequently had a history of hypertension, diabetes mellitus, congestive heart failure, renal dysfunction and obesity. In a multivariate analysis, taking account of age, history of cardiovascular diseases and renal dysfunction, female sex appeared as a significant independent predictor of mortality during the 30 days after coronary artery bypass grafting (P < 0.05), but not thereafter. Various postoperative complications including neurological deficit, hydro- and pneumo-thorax, perioperative myocardial damage and the need for assist devices and prolonged reperfusion were more common in females than males. CONCLUSION: Females run an increased risk of early death and the development of postoperative complications after coronary artery bypass surgery as compared with males. Late mortality does not appear to be influenced by gender and the long-term benefit of the coronary artery bypass graft operation is similar in men and women.

Aortic valve replacement with a pulmonary autograft in infants with critical aortic stenosis.

Seven patients with critical aortic stenosis underwent aortic valve replacement with a pulmonary autograft (the Ross operation) between the ages of 5 weeks and 9 months. The operation was considered mandatory for survival because of continued severe heart failure or valve avulsion. Six of the patients had undergone unsuccessful previous palliations, such as commissurotomy, balloon dilation, and transventricular valvotomy, performed singly (n = 1) or in combination (n = 5). The other patient with a severely hypoplastic aortic valve ring underwent the Ross procedure as a primary operation. Two operative deaths occurred. In both cases severe endocardial fibroelastosis was detected at autopsy. One late death 1 year after the operation resulted from progressive hypertrophic cardiomyopathy and pulmonary hypertension. The rest of the patients are doing well, without medications. Apart from trivial regurgitation in two patients, the pulmonary autograft is performing well.

Protective effects of an indenoindole antioxidant on coronary endothelial function after long-term storage.

Experiments were designed to evaluate function of the endothelium and smooth muscle of coronary arteries following storage of hearts in cardioplegia containing an inhibitor of lipid peroxidation (H 290/51, cis-7-methyl-9-methoxy-5,5a, 6,10b tetrahydroindeno [2,1-b] indole). Canine hearts were perfused with crystalloid cardioplegia (Plegisol, 15 ml/kg, 4 degrees C) and left circumflex arteries were isolated and studied either immediately (group I, n = 6), or after storage of the hearts at 4 degrees C for 10 (group II, n = 6) or 24 hr with (group III, n = 6) or without (group IV, n = 6) addition of H 290/51. The final concentration of H 290/51 was 1 mumol/L. Arteries were removed, cut into rings, and suspended in organ chambers for measurements of isometric force. In selected rings, the endothelium was removed in order to study the function of the smooth muscle. In order to discriminate effects of ischemia/reperfusion and protective properties on coronary endothelium or smooth muscle, drugs with different mechanisms were used. The function of the endothelium were studied with the alpha 2-adrenergic agonist UK 14,304, bradykinin and A 23187. The smooth muscle function were studied with isoproterenol and nitric oxide. Endothelium-dependent relaxations to the alpha 2-adrenergic agonist UK 14,304 and bradykinin, but not to A 23187, were reduced significantly in arteries from hearts stored for 24 hr in cardioplegic solution alone. Relaxations of arteries from hearts stored for 24 hr with H 290/51 were comparable to those arteries from hearts that were not stored. Endothelium-independent relaxations to isoproterenol and nitric oxide among the different groups were comparable. These results suggest that storage of canine hearts with crystalloid cardioplegia selectively inhibits endothelium-dependent relaxations mediated by receptor activation. Inhibition of lipid peroxidation with H 290/51 preserves these relaxations and may therefore represent a therapeutic alternative to preserve hearts used for transplantation.

Mechanical versus biological valve prosthesis: a ten-year comparison regarding function and quality of life.

To determine the long-term outcome of biological and mechanical heart valve prostheses, we compared the Biocor, a new generation of porcine bioprosthesis, with the St. Jude Medical mechanical prosthesis. One hundred consecutive patients operated on between 1983 and 1985 with the Biocor in the aortic, mitral, or both positions (without concomitant cardiac procedures) were followed until January 1993, together with 100 matched patients implanted with the St. Jude valve. The mean age was 66 and 67 years, respectively. The follow-up was 100% complete. Valve-related mortality differed significantly, with a freedom rate of 80.7% +/- 9.0% for the St. Jude group and 97.7% +/- 1.6% for the Biocor group. There were few thromboembolic events, with no significant difference between the groups. Anticoagulant-related hemorrhage occurred almost exclusively in the St. Jude group (2.3%/patient-year), and reoperations were required almost exclusively in the Biocor group (1.8%/patient-year). The occurrence of all valve-related complications (mortality plus morbidity) differed markedly, with an actuarial freedom at 10 years of 55.8% +/- 9.8% for St. Jude and 80.0% +/- 4.4% for the Biocor. Quality of life and echocardiographic measurements did not differ significantly between the groups. We conclude from this study that the long-term performance of the Biocor and St. Jude are comparable, even though valve-related complications tended to be fewer in the Biocor group, with a significantly lower incidence of valve-related death.

Similar quality of life after heart valve replacement with mechanical or bioprosthetic valves.

The goal of this study was to determine if there was a difference in the quality of life (QoL) between patients receiving bioprosthetic (Biocor, BIO) or mechanical (St. Jude Medical, SJM) valve prosthesis. In January 1993 we assessed the psychological outcome of heart valve surgery among 183 (87 BIO, 96 SJM) of 220 survivors in a selected and matched cohort of 140 BIO and 140 SJM recipients who had their valve replacement between 1983 and 1989. The BIO and SJM groups were equal in terms of mean age, gender, valve position, educational level, marital status and follow up time. Questions concerning QoL, in terms of coping capacity, social support, and general emotional status as well as emotions concerning valve-related complications, were answered by the patients marking a non-graded visual analogous scale, ranging from total agreement to total disagreement. We found no significant difference between patients receiving BIO and those receiving SJM prostheses regarding coping capacity (62 +/- 2 vs. 65 +/- 2), social support (77 +/- 3 vs. 76 +/- 2), or emotional status (63 +/- 3 vs. 65 +/- 3). When subdividing patients by age below and above 60 years, gender, functional class, valve position and complication, we found several significant differences, but the two prosthetic groups were largely similar. Females had a significantly lower level of coping capacity and emotional status than males. Coping capacity and emotional status were significantly correlated with functional class, while social support was not. Coping capacity tended to be lower among patients who had experienced complications and this was more pronounced with BIO.(ABSTRACT TRUNCATED AT 250 WORDS)

Preoperative risk indicators of death at an early and late stage after coronary artery bypass grafting.

The aim of the study was to describe mortality during a period of two years after coronary artery bypass surgery (CABG) in relation to preoperative risk factors. Included were all the patients in western Sweden in whom CABG was performed between June 1988 and June 1991, without concomitant procedures or re-operations. The study was prospective in design. In all, 2000 patients with a median age of 64 years were operated upon. Early (within 30 days) mortality was 3.0% and late (30-day-2-year) mortality was 4.2%. Total two-year mortality was 7.1%. For patients undergoing coronary artery bypass grafting, the factors found to be independently predictive of early mortality were female sex, renal dysfunction (creatine clearance < 60ml/min), left main stenosis, number of diseased vessels, previous myocardial infarction, and functional class. We found that a history of congestive heart failure, a history of cerebrovascular disease, diabetes mellitus, renal dysfunction and intermittent claudication were independent risk factors for late mortality. In conclusion, with the exception of renal dysfunction, preoperative risk factors for death within 30 days after CABG differ from risk factors for death between 30 days and two years after CABG.