Endonuclein is a cell cycle regulated WD-repeat protein that is up-regulated in adenocarcinoma of the pancreas

The transcript encoding endonuclein, the human homolog of yeast PWP1, was previously found up-regulated in pancreatic cancer tissue. By immunohistochemistry we detected a ubiquitous presence in several tissues examined: skin, liver, thyroid gland, heart muscle, neurons, kidney, bladder, pancreas, adrenal gland, ovary, uterus, testis and prostate gland. We especially noticed that normal pancreatic exocrine cells exhibited low protein levels while pancreatic adenocarcinoma cells revealed high levels. We found a heterogeneous subcellular distribution, especially with varying nuclear levels. In proliferating cells endonuclein protein expression and localization was cell cycle dependent, with increasing levels and nuclear focusing during the interphase toward mitosis. Ultrastructural analysis revealed ER and nuclear localization. Endonuclein contains five WD-repeats, indicating a putative role in crucial regulatory activities in the nucleus as well as in the ER.

The pulmonary vasculature in a neonatal porcine model with increased pulmonary blood flow and pressure

INTRODUCTION

Hypertension and hyperperfusion of the pulmonary vascular bed in the setting of congenital cardiac malformations may lead to progressive pulmonary vascular disease. To improve the understanding of the basic mechanisms of this disease, there is a need for clinically relevant animal models which reflect the disease process.

MATERIAL AND RESULTS

We randomly allocated 45 newborn pigs, at the age of 48 hrs, to groups in which there was either construction of a 3 mm central aorto-pulmonary shunt, undertaken in 9, or ligation of the left pulmonary artery, achieved in 13. Controls included sham operations in 13, or no operations in 10 pigs. Follow-up was continued for three months. The interventions were compatible with survival in most pigs. The shunts resulted in an acute 85% increase in systolic pulmonary arterial pressure, and a more than twofold increase in pulmonary blood flow. By three months of age, nearly all shunts had closed spontaneously, and haemodynamics were normal. Ligation of the left pulmonary artery resulted in a normal total pulmonary blood flow, despite only the right lung being perfused, and a 33% increase in systolic pulmonary arterial pressure. These haemodynamic changes were maintained throughout the period of study. In both groups, histomorphometry revealed markedly increased muscularity of the intra-acinar pulmonary arteries. Circulating levels of endothelin were normal in the shunted animals, and elevated in those with ligation of the left pulmonary artery.

CONCLUSION

In neonatal porcine models of pulmonary vascular disease, created by construction of 3 mm central aorto-pulmonary shunts and ligation of one pulmonary artery, we observed histopathological changes of the pulmonary vasculature similar to early hypertensive pulmonary vascular disease in humans. Elevated circulating levels of endothelin were associated with abnormal haemodynamics rather than abnormal pathology. These findings could be valuable for future studies on the pathogenesis of hypertensive pulmonary vascular disease associated with congenital cardiac malformations.

Morphological considerations of peri- and myocarditis

In medicine, and thus in pathology, there are areas/topics of fashion and they shift from time to time. Pericardial diseases are not fashionable. Myocarditis is, and has been for a long time. Due to new ways of retrieving tissue samples from the pericardium the modern diagnostic tools such as immunohistochemistry and molecular pathology can be applied in this context as they have been in myocarditis for a long period. The diagnosis of inflammation rests on many other findings than morphological alterations and it is indeed questionable if inflammation is solely a morphological diagnosis. The methodologies of pathology can be improved and used in a better and more purposeful way even under routine conditions. It is concluded that morphology is still mandatory to make a final diagnosis of peri- and myocarditis.

Sampling, sampling errors and specimen preparation

To obtain an adequate cervical smear for making a correct cytologic diagnosis, smear taking, laboratory handling and interpretation must be optimal. Many people are involved, and only by a combined effort of all links can this target be seriously approached: the smear takers will have to be open minded about technical improvements and read the morphologic descriptions cautiously; in the laboratory, cytotechnicians and physicians will have to challenge themselves and each other. It is mandatory to discard specimens that do not meet general standards of adequacy. At present a host of new techniques are being implemented. It is not feasible for all laboratories to be engaged in testing these new methods, but we are all requested to follow the development the best we can and switch to new ways when justified. Our working conditions are very different; therefore, it is our professional responsibility and plight to respond at the right time. So far the conclusion is that the conventional Pap smear is the international standard of care for the diagnosis of cervical cancer precursers in cancer screening programs. Certainly, this may change within a very short time. Liquid-based techniques, and in particular HPV technologies, are just around the corner.

Monocyte chemoattractant protein 1 (MCP-1) in temporal arteritis and polymyalgia rheumatica

OBJECTIVE

To examine the localisation of monocyte chemoattractant protein 1 (MCP-1) in the inflamed vessel wall in temporal arteritis (TA) and to measure MCP-1 in plasma both in patients with TA and patients with polymyalgia rheumatica (PMR).

METHODS

By immunohistochemical techniques MCP-1 was localised to the vessel wall in patients with TA. In TA, PMR, and healthy controls MCP-1 was quantified by enzyme linked immunosorbent assay (ELISA) in plasma.

RESULTS

MCP-1 was localised to the majority of mononuclear cells, some smooth muscle cells, and giant cells in the arterial biopsy specimens from 12 patients with histologically verified TA. In all sections, including the vasa vasorum, the endothelium stained positive. In the intima 73% (range 57-91%), in the media 49% (range 32-67%), and in the adventitia 74% (range of 62-91%) of all cells stained positive. In plasma MCP-1 was significantly raised in untreated TA (n=33) and untreated PMR (n=27) compared with healthy controls (n=12). Untreated TA plasma levels of MCP-1 (mean 391 pg/ml (range 82-778 pg/ml)) were similar to untreated PMR plasma levels (mean 402 pg/ml (range 29-1153 pg/ml)), and no significant difference was found between the two groups of patients. In both patients with TA and patients with PMR no correlation was found between the plasma level of MCP-1 and the erythrocyte sedimentation rate, haemoglobin concentration, and CD4/CD8 ratio.

CONCLUSIONS

These results show that MCP-1 plays a part in the disease processes of TA and PMR.

Functional remodelling and left ventricular dysfunction after repeated ischaemic episodes. A chronic experimental porcine model

This experimental study was set up to investigate left ventricular function and remodelling after repeated ischaemic episodes using magnetic resonance imaging (MRI). A significant reduction in mortality due to coronary heart disease (CHD) has been explained by both a decline in the incidence of acute myocardial infarction (AMI) and an improved post-AMI survival rate, suggesting a change in the natural history of CHD. Experimental intracoronary microembolization can induce different ischaemic patterns and the functional impact of repeated ischaemic episodes different from occlusion of central epicardial arteries can be studied. In this study repeated intracoronary microembolizations were performed in 20 domestic pigs. After 129 d, MRI was performed for assessment of left ventricular volume, mass and wall stress. Six pigs underwent serial MRI at baseline, immediately after embolization and at the end of the observation period. Microembolizations induced acute myocardial infarct expansion and increased left ventricular wall stress preceding chronic remodelling. End systolic and end diastolic volumes increased from 15.1 +/- 2.7 cm3 to 41.3 +/- 11.5 cm 3 (p < 0.002), and from 52.0 +/- 6.7 cm3 to 81.1 +/- 9.2 cm3 (p < 0.0007), respectively. End systolic wall stress increased from and 17.5 +/- 2.7 to 29.7 +/- 6.2 N/m2 (p < 0.001). Left ventricular filling pressures and cardiac index were unchanged. Histological examination revealed a diffuse pattern of perivascular fibrosis covering 12 +/- 3% of the left ventricular wall. This study demonstrates that repeated ischaemic episodes different from confined regional myocardial infarctions induce acute infarct expansion and chronic left ventricular remodelling in pigs. Serial assessment of absolute left ventricular volumes and mass is important during acute/chronic remodelling.

Malignant myxoid endobronchial tumour: a report of two cases with a unique histological pattern

AIMS

To present two cases of malignant endobronchial myxoid tumours with a highly distinctive sarcomatoid pattern not previously described at this site, and discuss their histogenesis in relation to previously documented endobronchial neoplasms.

METHODS AND RESULTS

Both tumours presented in young adult females and were purely sarcomatoid with interweaving cords of small uniform, rounded or slightly elongated cells lying within a myxoid stroma. The stroma was alcian blue positive, but sensitive to hyaluronidase in both cases. The tumour cells contained a small volume of periodic acid-Schiff-positive eosinophilic cytoplasm and stained positively for vimentin only, but there also was a prominent background population of CD68-positive dendritic cells. Ultrastructural studies showed that the tumour cells contained an excess of rough endoplasmic reticulum, with some of the cisternae appearing dilated, and scalloping of the cell surfaces, although no intracisternal tubules were identified.

CONCLUSIONS

Although the histological pattern was most reminiscent of extraskeletal myxoid chondrosarcoma, the sensitivity of the stroma to pretreatment with hyaluronidase precluded the diagnosis. However, there were similarities with the sarcomatoid component of malignant salivary gland-type mixed tumours of the lung and this tumour possibly represents a variant of a bronchial gland tumour. Despite this uncertainty over origin, this pattern should be recognized as part of the differential diagnosis of myxoid tumours in the lung, as an apparently indolent type of malignant endobronchial neoplasm.

Species differences in expression of angiotensin II receptors and angiotensin-converting enzyme in human, canine and rat mitral valve leaflets

In normal valvular collagen turnover in the rat, angiotensin (Ang) II and angiotensin-converting enzyme (ACE) seem to be involved. In common human and canine valvular diseases, changes in valvular collagen play a pathogenetic role and the valvular renin-angiotensin system is therefore of particular interest in these species. Healthy mitral valve leaflets and adjacent left ventricular myocardium were taken from five rats and five dogs immediately after euthanasia, and from five humans at autopsy. The valvular and myocardial Ang II receptors and ACE were detected and measured by quantitative autoradiography. In rat valves, high levels of Ang II receptors and ACE were found. In human and canine valves, insignificant levels were found. Significant myocardial levels of Ang II receptors and ACE were found only in the rat. The study demonstrated major species differences regarding the level of valvular and myocardial Ang II receptors and ACE in man, dog and rat. The lack of valvular Ang II receptors and ACE in man and dog, suggest that the renin-angiotensin system plays a minor, if any, role in the physiological valvular collagen formation in these two species. The findings in humans, however, need to be confirmed using fresh material.

hnRNPs H, H' and F behave differently with respect to posttranslational cleavage and subcellular localization

hnRNPs H, H' and F belong to a subfamily of the hnRNPs sharing a high degree of sequence identity. Eukaryotic expression and specific C-terminal antibodies were used to demonstrate great variation in the intracellular fate of the proteins. hnRNPs H and H' become posttranslational cleaved into C-terminal 35 kDa proteins (H(C), H'(C)) and possibly into N-terminal 22 kDa proteins. No detectable cleavage was observed for hnRNP F. hnRNP H/H' is almost exclusively localized to the nucleus of many cell types while hnRNP F varies from a predominant nuclear localization in some cells to a predominant cytoplasmic localization in other cells. The different fates may reflect differences in functional roles that so far only have included nuclear functions. The presence of significant quantities of hnRNP F in the cytoplasm of many cells indicates that it also may have a functional role here.

The hemodynamic impact of diffuse myocardial ischemic lesions: an animal experimental model based on intracoronary microembolization

In ischemic heart disease, left ventricular function is affected by a diffuse and segmental loss of myocardium. The decline in the incidence of myocardial infarction and improved early revascularization in acute transmural ischemia predict a change in the natural history of ischemic heart disease. It is now believed that, minor ischemic episodes, which are known to induce multifocal myocardial degeneration, will predominate in the near future. The objective of the present study was to develop a clinically relevant experimental model for investigation of the pathophysiological significance of diffuse ischemic myocardial lesions. Cardiac performance was gradually depressed by selective intracoronary microembolization in 13 pigs. Left ventricular function was quantitated by ejection fraction (EF), pulmonary pressure, cardiac output, and derivatives of left ventricular pressure. Left ventricular volume was estimated by epicardial echocardiography, using a new, unbiased stereological volume estimator. A chronic substudy was performed in order to characterize the histological changes and to evaluate the feasibility of establishing a chronic preparation of the model. Embolization induced acute left ventricular dysfunction; left ventricular pressure change decreased from 966+/-274 to 637+/-146 mmHg/s, and early diastolic relaxation from 1403+/-515 to 824+/-344 mmHg/s, respectively. Ejection fraction decreased by 45%+/-5% and cardiac output by 29%+/-11%. End-diastolic volume increased significantly, from 66.1+/-13.2 to 77.0+/-19.4 cm3, and end-systolic volume increased from 35.9+/-13.9 to 52.3+/-7.6 cm3. No change in heart rate or left ventricular filling pressure was observed. Diffuse ischemic myocardial injury was identified after a mean follow-up of 40 days. Intracoronary microembolization induces acute left ventricular dysfunction due to microinfarcts. Increased left ventricular end-diastolic volume is the initial compensatory response to the acute impairment of cardiac performance in nontransmural myocardial ischemia. This model is suitable for the evaluation of the hemodynamic changes secondary to acute and chronic diffuse loss of functional myocardium.

Alpha-cardiac actin is a novel disease gene in familial hypertrophic cardiomyopathy

We identified the alpha-cardiac actin gene (ACTC) as a novel disease gene in a pedigree suffering from familial hypertrophic cardiomyopathy (FHC). Linkage analyses excluded all the previously reported FHC loci as possible disease loci in the family studied, with lod scores varying between -2.5 and -6.0. Further linkage analyses of plausible candidate genes highly expressed in the adult human heart identified ACTC as the most likely disease gene, showing a maximal lod score of 3.6. Mutation analysis of ACTC revealed an Ala295Ser mutation in exon 5 close to 2 missense mutations recently described to cause the inherited form of idiopathic dilated cardiomyopathy (IDC). ACTC is the first sarcomeric gene described in which mutations are responsible for 2 different cardiomyopathies. We hypothesize that ACTC mutations affecting sarcomere contraction lead to FHC and that mutations affecting force transmission from the sarcomere to the surrounding syncytium lead to IDC.

Parvovirus B19 infection associated with myocarditis following adult cardiac transplantation

A 56-year-old woman underwent an uneventful cardiac transplantation due to dilated cardiomyopathy. One week later the patient developed clinical and histological signs of myocarditis. We report for the first time a case of myocarditis in an adult heart transplant recipient, possibly induced by parvovirus B19, as evidenced by the finding of specific IgM in serum and specific DNA in the myocardial cells. Furthermore, this is the first time parvovirus B19 DNA has been observed in the myocardium of an adult. In conclusion, parvovirus B19 should be recognized as a potential pathogen causing myocarditis in heart transplant recipients. In order to establish a definite and rapid diagnosis, a search for specific IgM should be supplemented with PCR investigations of serum and myocardial biopsies when available.

Sudden unexpected cardiac deaths among young Swedish orienteers--morphological changes in hearts and other organs

During the years 1979-1992 an accumulation of sudden unexpected cardiac deaths (SUD) occurred among young Swedish orienteers. A reevaluation of material saved from 16 autopsies was undertaken. Myocarditis was most frequent. It was found in different stages in the majority of cases, indicating subacute or chronic disease with ongoing reparative processes. There were severe morphological changes in all cases. All but one showed a picture of fibrosis and unspecific hypertrophy and/or degenerative changes in myocytes. The hearts were classified into three groups (A-C), based on the morphological picture of the retrieved heart tissue and the macroscopic description. Group A comprised five cases in which areas with active myocarditis combined with areas of healing or healed myocarditis widely distributed in the left ventricle were the only morphological changes found. Group B comprised four cases demonstrating foci of myocarditis in different stages in the left ventricle and changes resembling those found in arrhythmogenic right ventricular dysplasia (ARVD), including degenerative changes with fibrosis and fatty infiltration located in either ventricle. Group C comprised the remaining seven cases. In none of the cases were coronary artery or valvular anomalies present, nor significant coronary sclerosis or changes outside the heart that could cause SUD.

Animal experimental implantation of an atrial septal defect occluder system

OBJECTIVE

To establish the implantation technique for the atrial septal defect occluder system (ASDOS) device in an experimental animal model and to determine long term mechanical stability of the device and its in vivo properties in terms of biocompatibility and tissue reaction.

MATERIALS AND METHODS

An atrial septal defect was created and the device implanted in 17 pigs (mean weight 30 kg). The implantation technique was refined and modified because of initial technical and anatomical complications during nine acute pilot studies. The technique proved to be feasible in eight subsequent survival studies. Four pigs were electively killed three months after implantation (group 1). The remaining four pigs were killed six months after implantation (group 2).

RESULTS

Necropsy showed all devices were embedded in soft tissue three months after implantation. Microscopic examination of atrial septal tissue showed an acute granulomatous inflammatory reaction in group 1 and fibrosis in group 2. The intensity of the inflammatory reaction around the device was clearly milder in group 2, indicating a decline in the inflammatory response with time. Clinical and biochemical investigations indicated acceptable biocompatibility of the device.

CONCLUSION

The implantation technique for the ASDOS device in a chronic pig model has been established. Biocompatibility of the device was acceptable.

Latissimus dorsi cardiomyoplasty: a chronic experimental porcine model. Feasibility study of cardiomyoplasty in Danish Landrace pigs and Göttingen minipigs

Cardiomyoplasty is an experimental treatment for end-stage heart failure. We hypothesized that the porcine latissimus dorsi muscle (LDM) in an experimental porcine model is a suitable surrogate for a clinically relevant evaluation of this concept. Fourteen Danish Landrace (DL) pigs and six Göttingen minipigs (GM) were studied. The LDM was evaluated immediately after surgical dissection and in various phases: phase 1 (n = 4)--outcome of a partial vascular isolation (vascular delay), 2 to 3 weeks prior to heart wrapping in DL pigs; phase 2 (n = 6)--long-term flap survival of nonstimulated LDM cardiomyoplasty in DL pigs; phase 3 (n = 6)--outcome of nonstimulated cardiomyoplasty in GM; phase 4--one DL pig had dynamic cardiomyoplasty performed and was subjected to low-intensity LDM stimulation for 8 months. Isolation of the LDM of DL pigs and GM as a pedicled graft had no acute deleterious impact on the global blood supply. In phase 1a, partial vascular isolation and in situ recovery of the LDM resulted in a muscle encapsulated in fibrotic tissue, which hampered a later heart wrap. In phase 1b, a less extensive dissection diminished fibrosis and allowed subsequent wrapping. In phase 2, after 6 weeks of nonstimulated LDM cardiomyoplasty, the LDM of DL pigs was viable, with excellent heart-muscle integration. In phase 3, the same procedure applied in GM yielded the same result as that in DL pigs, but with a higher success rate owing to the learning phase.

Myocardial structure as a determinant of pre- and postoperative ventricular function and long-term prognosis after valve replacement for aortic stenosis

BACKGROUND

Long-term results after aortic value replacement for aortic stenosis can be correlated to a cardiac-related pre-operative risk profile. This predictability indicates that there is a common basis in subtle or overt structural abnormalities of left ventricular myocardium.

METHODS AND RESULTS

Forty-nine patients aged 24-82 (mean 61) years, with aortic stenosis had a full wall thickness transmural biopsy of the left ventricular antero-lateral free wall during aortic valve replacement. Echocardiography and radionuclide ventriculography were performed prior to, and 18 months (n = 41) after, the operation. Postoperative follow-up to a maximum of 7.7 years was 100% complete. Pre-operatively, all patients had an increase in both the left ventricular mass index (202 +/- 67 g.m-2) and the muscle cell diameter (41 +/- 8 microns); other morphological data included a muscle cell nucleus volume of 752 +/- 192 microns3, a muscle cell mass index of 163 +/- 54.m-2, and a fibrous tissue mass index of 39 +/- 16 g.m-2. Patients with a pre-operative episode of clinical left ventricular failure (n = 19) had significantly greater morphological variables than those without. Pre-operative ejection fraction and other measures of systolic function correlated inversely with the morphological data, except for the fibrous tissue mass index; diastolic function indices correlated inversely with all the morphological variables. At the 18-month re-study, the same general picture was noted, but with an underlying strengthening, especially of the muscle cell mass index. Overall, the mass index dropped to 152 +/- 51 g.m-2 (P < 0.0001), but in 17% of the patients it became normal; the mass index at 18 months was directly correlated to morphological variables. A high muscle cell nucleus volume was identified as an independent predictor of early and late mortality.

CONCLUSIONS

Abnormalities of the hypertrophied left ventricular muscle cell and the degree of muscle hypertrophy are, to some degree, underlying determinants of pre-operative symptomatology, pre- and postoperative ventricular function, and early and late mortality after valve replacement for aortic stenosis. Incomplete hypertrophy impaired results, was related to pre-operative myocardial structural abnormalities.

Gentacoll hampers epithelialisation and neovascularisation in excisional wounds in hairless mice

Our aim was to analyse the effect of Gentacoll on the rate of epithelialisation and neovascularisation in wound healing. Standardised circular full thickness dermal wounds 2.25 mm in diameter were created on the dorsum of each ear on 24 hairless homozygous mice (n = 48). The cartilaginous layer was left intact. The wounds were treated in a randomised blinded fashion with bovine collagen implants with gentamicin (Gentacoll) (n = 17); bovine collagen implants without gentamicin (n = 15); and Silicone film (n = 16). Epithelialisation and neovascularisation were measured directly by intravital video-microscopy and computerised planimetry immediately after the wounds had been made and every third day until the wounds closed. Only five of the wounds treated with Gentacoll (n = 17) epithelialised completely; and their mean (SEM) epithelialisation time was 22.8 (1.6) days, significantly longer than controls without gentamicin (n = 15) for which the corresponding figures were 14.5 (0.6) days. In nine wounds treated with Gentacoll the ear cartilage in the wound bed perforated and two wounds developed severe inflammation, which was followed by self-mutilation. Neovascularisation was incomplete in all of the wounds in the Gentacoll group, whereas it was completed by 25.3 (0.7) days in the control group treated with implants without gentamicin. In the silicone treated group (n = 16), epithelialisation was completed by 12.7 (0.7) days and neovascularisation by 25.1 (0.5) days. None of wounds treated with collagen or silicone alone showed reactions similar to the Gentacoll-treated ears. Gentacoll hampers epithelialisation and neovascularisation, and might damage exposed cartilage.

[Arrhythmogenic right ventricular cardiomyopathy]

Arrhythmogenic right ventricular dysplasia is a rare cardiomyopathy, but a frequent cause of ventricular tachyarrhythmia and sudden cardiac death among young otherwise healthy individuals. This article contains a review of the current knowledge on epidemiology, diagnosis, symptoms and signs as well as theories on etiology and pathogenesis, prognosis and treatment. The aim is to draw attention to the disease as a cause of syncope, ventricular tachycardia and sudden cardiac death.

Pharmacological characterization of coronary small arteries from pigs with chronic ischaemic myocardial remodelling

1. The effect of chronic ischaemic myocardial remodelling on small coronary artery reactivity in vitro was studied in a newly developed pig model. 2. Pigs were subjected to selective intracoronary embolizations with microspheres in the left anterior descending artery and circumflex artery causing scattered myocardial fibrosis. After an observation period of 130 days, heart dimensions and ejection fraction were determined with magnetic resonance imaging. Small arteries were isolated from the left ventricle and mounted as ring preparations in a myograph. Control arteries were taken from matched non-embolized pigs. 3. Compared with control pigs, end-systolic and diastolic volumes increased and left ventricular mass nearly doubled in embolized pigs. This indicates substantial myocardial hypertrophy, as the fraction area of fibrosis was only 12%. 4. Coronary small arteries preconstricted with 30 mmol/l KCI showed a normal contractile response to acetylcholine and 5-hydroxytryptamine. Sensitivity of the relaxation to bradykinin was nearly 3-fold increased and also slightly enhanced to isoprenaline in arteries from embolized pigs compared with controls, whereas relaxation to 5-hydroxytryptamine in the presence of ketanserin was similar. After inhibition of nitric oxide synthase with NG-nitro-L-arginine the sensitivity to acetylcholine increased to a similar extent in arteries from embolized pigs and controls. NG-Nitro-L-arginine abolished the relaxing effects of bradykinin and of 5-hydroxytryptamine in the presence of ketanserin. 5. We conclude that both the contractile function of the smooth muscle cells and the endothelial production or action of nitric oxide is preserved or slightly enhanced in coronary small arteries from pigs with chronic myocardial remodelling.

Endogenous TGF-beta 1 and TGF-beta 2 are not essential for epithelialization and neovascularization in the hairless mouse ear wound model

BACKGROUND AND AIMS

TGF-beta stimulates neovascularization and epithelialization in healing wounds, yet relatively little is known about the mechanisms involved. Using the hairless mouse ear wound model, we studied the effects endogenous TGF-beta 1 and TGF-beta 2 have on epithelialization and neovascularization following the application of neutralizing antibodies.

MATERIAL AND METHODS

Forty-three adult male hairless mice had an excisional wound made on the dorsum of each ear. Using vital microscopy, epithelialization and neovascularization were measured every third day until completion. TGF-beta 1 and TGF-beta 2 antibody, control-IgG, or phosphate buffered saline (PBS) were applied to the wounds.

RESULTS AND CONCLUSIONS

Excisional wounds treated with anti-TGF-beta 1 and anti-TGF-beta 2, IgGcontrol IgG, and PBS epithelialized in 11.2 +/- 0.5 days (N = 22), 10.9 +/- 0.6 days (N = 17), and 10.6 +/- 0.6 days (N = 15), respectively and neovascularized in 27.9 +/- 0.5 days (N = 17), 27.1 +/- 0.8 days (N = 14), and 26.1 +/- 0.8 days (N = 10), respectively (mean +/- SEM). There were no significant differences in time to epithelialization and neovascularization between the three groups. Furthermore, there were no differences in the average time course of epithelialization and neovascularization between the three groups throughout the healing process. We conclude that endogenous TGF-beta 1 and TGF-beta 2 are not essential for epithelialization and neovascularization in the hairless mouse ear wound model.

Impaired human coronary artery distensibility by atherosclerotic lesions: a mechanical and histological investigation

The objective of this study was to evaluate the relationship between human coronary artery distensibility and vessel wall morphology assessed by histomorphometry. Coronary artery pressure-cross-sectional area relations and distensibility were studied in excised autopsy hearts by means of a balloon-based impedance planimetric technique 2 cm from the aortic orifice of the arteries. Later the hearts were perfusion fixed at 100 mm Hg and cross-sectioned 17, 20 and 23 mm distal to the aortic orifice. The areas of lumen, intima and media were measured. Nineteen left anterior descending coronary arteries (LAD) and 15 right coronary arteries (RCA) from 25 hearts (12 women and 13 men) were investigated. The age of the subjects was 48-97 years (mean 73.8 years). Non-linear relations were found between balloon pressure and coronary cross-sectional area (according with the function y = a + bx0.5) and between balloon pressure and coronary distensibility, but there were no differences in these relations between the LAD and RCA. Subjects' age was positively correlated with wall thickness (r = 0.44, P < 0.05), intima area (r = 0.46, P < 0.01) and media area (r = 0.44, P < 0.05) of the coronary arteries. Additionally, the distensibility at low pressures was inversely correlated with arterial wall thickness (r = -0.37, P < 0.05). When focusing only on arteries with concentric atherosclerotic lesions, distensibility at low pressures was inversely correlated with arterial wall thickness (r = -0.57, P = 0.01) and intima area (r = -0.53, P < 0.05). Arteries with concentric lesions were less distensible at low pressures compared with arteries having eccentric lesions (5.4 +/- 0.8.10(-2) vs. 3.6 +/- 0.7.10(-2) kPa-1, P < 0.05) but this difference was absent at higher pressures. No difference in coronary artery distensibility was found between men and women. Age and distensibility were not correlated. These findings may have in vivo implications for complications to angioplasty procedures such as recoil and restenosis.

Ischemia and reperfusion of the porcine myocardium: effect on collagen

We studied the effect of acute myocardial infarction and late reperfusion on myocardial collagen in a closed chest porcine model, to investigate if any collagen degradation could be detected in blood samples and myocardium. Sixteen 60-80 kg pigs were used with six animals serving as controls and 10 submitted to ischemia-reperfusion. In the ischemia-reperfusion group the left anterior descending coronary artery was occluded for 6 h by inflation of a percutaneous transluminal coronary angioplasty balloon followed by reperfusion for 3 h. Blood samples were taken from the aorta and the coronary sinus and analyzed for creatine kinase and collagen degradation products, i.e. the N-terminal propeptide of procollagen type III (PIIINP) and C-terminal pyridinoline cross-linked telopeptide of collagen type I (ICTP). Myocardial tissue samples were analyzed for content of hydroxyproline, collagen volume fraction and amount of extractable PIIINP/dry weight. Transmission electron microscopy of biopsies was performed to evaluate myocytes and collagen structure outside and within the infarct zone. Creatine kinase showed a statistically significant increase during ischemia and reperfusion but we found no evidence of release of collagen degradation products either during ischemia or reperfusion compared with control. Myocardial content of hydroxyproline, collagen volume fraction and extractable PIIINP/dry weight did not differ between groups. Transmission electron microscopy of biopsies from the infarct zone showed myocyte damage but no visible evidence of collagen degradation when photos were evaluated blindly. In this porcine model of acute myocardial infarction and late reperfusion no release of collagen degradation products from the myocardium or any decrease in or damage to myocardial collagen was detected.

An increase in sudden unexpected cardiac deaths among young Swedish orienteers during 1979-1992

BACKGROUND

Sixteen cases of sudden unexpected cardiac death, 15 males and one female, are known to have occurred among young Swedish orienteers from 1979 to 1992, of which seven cases occurred between 1989 and 1992. This is considered to be indicative of an increased death rate.

RESULTS

Histopathological evaluation showed myocarditis in a higher than expected proportion of cases. In one such case, which we studied before the sudden unexpected death occurred, the victim had suffered a Chlamydia pneumoniae infection verified by serology, and a nucleotide sequence was found in the heart and lung by means of the polymerase chain reaction (PCR) that hybridized with a probe specific for that organism. Male Swedish orienteers do not, however, seem to have an increased rate of exposure to this agent. No further sudden unexpected deaths among young orienteers have occurred over the past 3.5 years. At the beginning of that period, attempts were made to modify training habits and attitudes.