Ventricular septal defects due to penetrating injuries of the heart

Four patients with traumatic ventricular septal defect following stab wound underwent successful open heart repair. All were symptomatic in spite of minimal hemodynamic disturbances. An additional lesion in the form of a fistulous tract between the aorta and the right atrium occurred in one case.     

Histochemical reactions of myocardial proteases during open heart surgery

Histochemical analysis of some lysosomal and sarcoplasmic proteolytic enzymes was assayed in human myocardial biopsies taken from 26 cardiopathic patients subjected to open heart operations, under extracorporeal circulation and protection with cardioplegic solution and hypothermia. The investigated myocardial proteases were: cathepsin B, cysteine aminopeptidase, acid gelatinases, trypsin-like endopeptidase, chymotrypsin-like endopeptidase and neutral gelatinases. The effects of surgical interventions appreciated by comparing the myocardium fragments harvested before, and at various intervals after aorta clamping (6-90 minutes) revealed disorders in the activity and compartmentalization of all the investigated proteases, whose histochemical reactions increased between 10 and 20 minutes after aorta clamping and manifested a lowering tendency with sarcoplasmic diffusion and extracellular release at longer periods than 20 minutes. The early activation of the neutral proteases and their sarcolemmal expression even before 10 minutes after aorta clamping, suggested the involvement of the nonlysosomal proteases in the first proteolytic events implied in the molecular membrane damage of the myocardial fibre. Sequential proteolytic cascades of abnormal neutral and acid proteases were emphasized as possible mediators and effectors of molecular and subcellular damages suffered by the myocardial fibers during the open heart operations, even under cardioplegic and hypothermic protection.     

Kinetic differences between Ca(2+)-dependent K+ channels in smooth muscle cells isolated from normal and atherosclerotic human aorta.

The properties of large conductance Ca(2+)-dependent K+ channels in smooth muscle cells (SMC) isolated from normal and atherosclerotic human aorta were studied using the patch-clamp technique. It was shown that SMC from normal human aorta possess a homogeneous population of normal Ca(2+)-dependent K+ channels. In atherosclerotic aorta two kinetically different types of these channels could be distinguished: along with normal 'long' (L)-type channels there appeared channels of 'short' (s)-type. Under similar conditions s-type channels had about a four times shorter mean open time. About five times higher [Ca2+]in was necessary for s-type channels to reach the probability of the channels being open equal to L-type channels. No differences in conductance and voltage dependency were found between the two channel types. Channels of the s-type resembled those previously described in SMC isolated from foetal human aorta. Thus, it can be suggested that during the development of atherosclerosis a population of SMC with s-type Ca(2+)-dependent K+ channels appears in human aorta.     

Lack of altered cyclic nucleotide phosphodiesterase activity in the aorta and heart of the spontaneously hypertensive rat

DEAE-cellulose chromatography demonstrated that the levels of the individual cyclic nucleotide phosphodiesterase were unchanged in the aorta and heart of the spontaneously hypertensive rat as compared with the normotensive control rat. Three peaks of cyclic nucleotide phosphodiesterase activity were observed in both heart and aorta. Peak I enzyme hydrolyzed predominantly cyclic GMP while peak III enzyme hydrolyzed predominantly cyclic AMP. Peak II enzyme was less specific but hydrolyzed more cyclic GMP than cyclic AMP The levels of phosphodiesterase activator in aorta and the responsiveness of peaks I and II from aorta and heart to activator were unchanged in the hypertensive rat. Therefore the decrease in cyclic AMP levels observed by others in aorta and heart of the spontaneously hypertensive rat were probably not due to altered phosphodiesterase activity.     

Endomorphins restored the endothelium-dependent relaxation of the rabbit aorta rings exposed to high D-glucose condition via NO-cGMP pathway

Rings of rabbit aorta that were both incubated in a high concentration of D-glucose and contracted submaximally by phenylephrine showed significantly decreased endothelium-dependent relaxations induced by acetylcholine. The cGMP production of aorta rings was also reduced. Treatment with endomorphins (1-1000 nmol/L) restored acetylcholine-induced relaxations of aorta rings incubated in high glucose concentrations and increased the cGMP synthesis. Moreover, this effect of endomorphins on endothelium was antagonized by naloxone, and the increase in the production of cGMP was also blocked.     

Functional morphology of the heart and of a new cephalic pulsatile organ in the blowfly Calliphora vicina (Diptera: Calliphoridae) and their roles in hemolymph transport and tracheal ventilation

In the blowfly Calliphora vicina (Diptera: Calliphoridae), the morphology of the dorsal vessel and of a new cephalic accessory pulsatile organ (CPO) were analysed with light-microscopic, SEM and TEM techniques. The CPO and neck aorta are reconstructed 3-dimensionally by computer-aided design. The pulse activity of the CPO and of the heart was measured in intact flies over periods of several hours or days using contact-thermography with laser beam heat-marking. The intratracheal pressure was simultaneously measured at the anterior thoracic spiracle. The dorsal vessel is constructed of pairs of left–right alternating cells. Its enlarged chamber in the anterior abdomen contains two pairs of incurrent ostia, its posterior narrower heart tube possesses three pairs of incurrent ostia and paired caudal excurrent openings. The aorta opens with a funnel-like opening in the neck. Proportions, arrangement and ultrastructure of the aorta, heart cells and pericardial muscles are described. Cushionlike sarcoplasmic protrusions of heart cells (pair no. 17) probably function as internal valves. The neck aorta is constructed of a cuticular ‘roof’ deviating from the dorsal neck membrane and a ventral longitudinal muscle ‘floor’. The aorta is not kept open because of missing muscle or connective tissue strands. The underside of the CPO is fused with air sacs that function as antagonists to the muscles. The heart reverses its beat periodically in resting and active flies. During the longer forward-pulse periods, mean frequency is lower (about 3.0 Hz at Ta 20°C), during the shorter backward periods mean frequency is higher (4.6 Hz). The CPO beats only during forward-pulse periods of the heart with an independent and slower pulse rate (1.8 Hz). The CPO-pulses produce positive pressure pulses at the anterior thoracic spiracle. During backward-pulse periods of the heart and pulse pause of the CPO, a continuous negative pressure arises at the thoracic spiracle instead of pressure pulses. The intimate connection of an accessory pulsatile organ with tracheal air sacs makes it work as a bifunctional pump for hemolymph distribution and tracheal ventilation. Neurosecretory and synapsing innervation of the CPO in connection with aorta, heart and pericardial septum muscle innervation suggest that both organs are regulated and that the duration of their periods is neuronally coordinated.     

Accumulation of 8-oxo-deoxyguanosine in cardiovascular tissues with the development of hypertension

Accumulation of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) in DNA is associated with mutagenesis and cell death. Little attention has been given to the biological significance of 8-oxo-dG accumulation in cardiovascular tissues during the different stage of hypertension and its prevention. We thus investigated the levels and localization of both 8-oxo-dG accumulation and expression of MTH1, which hydrolyzes 8-oxo-dGTP to prevent its incorporation into DNA, in the thoracic aorta prepared from stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched Wister-Kyoto rats (WKY), aged 5-32 weeks. HPLC-MS/MS analysis revealed that the levels of nuclear 8-oxo-dG in the aorta increased significantly in SHRSP, but not WKY, with aging. Immunohistochemical study revealed that both TUNEL reactivity and 8-oxo-dG immunoreactivity were increased in smooth muscle cells (SMC) and endothelial cells (EC) of the aorta with aging, and they exhibited similar distributions in serial sections. The number of 8-oxo-dG and TUNEL positive cells in EC, but not in SMC, was significantly higher in SHRSP than WKY at 32 weeks of age. In contrast, the expression levels of Mth1mRNA and MTH1 protein in the aorta were similarly decreased both in SHRSP and WKY with aging. However, the number of MTH1 expressing EC was remarkably increased in the older SHRSP compared to the younger ones or age-matched WKY. Hypertension significantly increased not only 8-oxo-dG accumulation but also the expression of MTH1 in EC of the aorta during aging. While accumulation of 8-oxo-dG in SMC of the aorta was slightly increased, the expression of MTH1 protein in SMC was rather decreased by hypertension. We thus suggest that MTH1 may protect EC in the aorta from the oxidative damage increased by hypertension.     

Technical Aspects of the Mouse Aortocaval Fistula

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta and inferior vena cava (IVC) are exposed. The proximal infrarenal aorta and the distal aorta are dissected for clamp placement and needle puncture, respectively. Special attention is paid to avoid dissection between the aorta and the IVC. After clamping the aorta, a 25 G needle is used to puncture both walls of the aorta into the IVC. The surrounding connective tissue is used for hemostatic compression. Successful creation of the AVF will show pulsatile arterial blood flow in the IVC. Further confirmation of successful AVF can be achieved by post-operative Doppler ultrasound.     

Immunolocalization of collagen types I and III in the arterial wall of the rat

Summary Collagen types I and III were located by immunofluorescence procedures in the aorta and coronary arteries of the rat. Type I collagen was most prevalent in the adventitia of the aorta with only small amounts present in the intima and media. Type III collagen appeared to be a significant component in the media of the aorta and also in the adventitia of both blood vessels. The intima and media of the coronary arteries did not stain strongly for either type I or III collagen. Neither staining procedure was altered with preincubation of the sections with hyaluronidase or chondroitinase ABC. These studies indicate that type III collagen is a major component of the adventitia which has previously not been recognized by immunohistochemical techniques, possibly due to masking of collagen staining with glycosaminoglycans.     

Mechano-biology in the thoracic aortic aneurysm: a review and case study

An aortic aneurysm is a permanent and localized dilatation of the aorta resulting from an irreversible loss of structural integrity of the aortic wall. The infrarenal segment of the abdominal aorta is the most common site of aneurysms; however, they are also common in the ascending and descending thoracic aorta. Many cases remain undetected because thoracic aortic aneurysms (TAAs) are usually asymptomatic until complications such as aortic dissection or rupture occurs. Clinical estimates of rupture potential and dissection risk, and thus interventional planning for TAAs, are currently based primarily on the maximum diameter and growth rate. The growth rate is calculated from maximum diameter measurements at two subsequent time points; however, this measure cannot reflect the complex changes of vessel wall morphology and local areas of weakening that underline the strong regional heterogeneity of TAA. Due to the high risks associated with both open and endovascular repair, an intervention is only justified if the risk for aortic rupture or dissection exceeds the interventional risks. Consequently, TAAs clinical management remains a challenge, and new methods are needed to better identify patients for elective repair. We reviewed the pathophysiology of TAAs and the role of mechanical stresses and mathematical growth models in TAA management; as a proof of concept, we applied a multiscale biomechanical analysis to a case study of TAA.     

Operations on large arteries; application of recent advances

With the use of anticoagulants to prevent recurrence of thrombosis it is now possible to open a major artery which has been occluded by a thrombus, remove the thickened lining with the clot and restore the continuity of the vessel. Free vein grafts have been used successfully to replace arterial segments in the extremities. Vein inlay grafts are preferred in dealing with aneurysms of the abdominal aorta. The aneurysmal wall can be used to support the venous segments. It has been possible to by-pass aneurysms of the abdominal aorta by anastomosing the splenic artery to the left iliac artery. The use of the left superficial femoral artery as a by-pass to supply blood to the right leg is described.     

OPERATIONS ON LARGE ARTERIES—Application of Recent Advances

With the use of anticoagulants to prevent recurrence of thrombosis it is now possible to open a major artery which has been occluded by a thrombus, remove the thickened lining with the clot and restore the continuity of the vessel. Free vein grafts have been used successfully to replace arterial segments in the extremities. Vein inlay grafts are preferred in dealing with aneurysms of the abdominal aorta. The aneurysmal wall can be used to support the venous segments.It has been possible to by-pass aneurysms of the abdominal aorta by anastomosing the splenic artery to the left iliac artery. The use of the left superficial femoral artery as a by-pass to supply blood to the right leg is described.     

Relationships among element contents in the intimal, middle, and external tunicae of the thoracic aorta

To examine an accumulation of elements within the arteries with aging, the authors investigated the element contents in the intimal, middle, and external tunicae of the thoracic aorta. The subjects consisted of six men and four women, ranging in age from 57 to 99 yr. The wall of the thoracic aorta was separated into the intimal, middle, and external tunicae by scrubbing the wall of the thoracic aorta with an edge of slide glass and the element contents were determined by inductively coupled plasma-atomic emission spectrometry. It was found that there were significant relationships among calcium, phosphorus, magnesium, sulfur, and sodium in both the intimal and middle tunicae of the aorta, but not in the external tunica. These results revealed that no significant differences were found in element compositions of deposits between the intimal and middle tunicae.     

Electroosmotic Characteristics of Canine Aorta and Vena Cava Wall

Experiments in which canine aorta and vena cava walls are subjected to electroosmosis in an open system at constant pressure are described. Electroosmosis reveals that the blood vessel walls studied have a negative zeta potential. The calculated zeta potentials are different for aorta and vena cava, -9.0 +/- 5.0 mv compared with -4.7 +/- 1.2 mv, respectively, and again of different magnitude with different bathing solutions. The calculated membrane pore charge per centimeter of effective pore surface in statcoulombs is approximately 6.2 x 10(3) for aorta compared with 3.5 x 10(3) for vena cava. The implications of the negative electroosmotic zeta potential in terms of the surrounding electric double layer, ion transport, and thrombosis are briefly discussed.     

Effect of phorbol ester on contractile response of aorta from endotoxic rats

The influence of phorbol ester on the isometric contractile response of aorta from endotoxic rats was examined. In endotoxic rat aorta, the contractile responses to KCl and phorbol 12,13-dibutyrate (PDBu) were both remarkably diminished, compared to those in control rat aorta. Preincubation with PDBu augmented the aortic contractile response to KCl in both control and endotoxic rats. This augmentative effect of PDBu was significantly more pronounced in endotoxic rats than in controls. When the contractile response to 80 mM KCl reached a plateau after PDBu pretreatment, addition of 5 mM CaCl2 (final concentration) to the organ bath completely reversed the diminished contractile response of endotoxic rat aorta to the control level. These results suggest that the hyporesponsiveness of endotoxic rat aorta to KCl may be caused by decreases in both protein kinase C mediated response and calcium sensitivity of vascular smooth muscle cells.     

The three-dimensional structure of the tunica intima and tunica media of the human fetal aorta studied by a new method]

A new method is developed for revealing the latent surfaces in the structure of organs by scanning electronic microscopy. The method is based on the treatment of specimens with potassium ethoxide until cells start to appear in the dissociating solution. Using this method, thoracic aorta of nine human fetuses at the stage of 20-28 weeks was studied. Subendothelial intima and media of human fetal aorta contain smooth muscle cells differing by their arrangement, shape and surface microrelief. The intima cells are arranged in a mosaic pattern formed of single cells or cell clusters. By means of cell processes they are connected with each other, as well as with endothelial and smooth muscle cells of the media. Smooth muscle cells in the inner part of the media also have processes and form an open network. Part of the cells penetrate the intima through pores of the inner elastic membrane. In the deeper layers of the media, laterally adjoining spindle-shaped smooth muscle cells are found. It is suggested that the observed cell polymorphism is due mostly to penetration of the media smooth muscle cells into subendothelium and modification of their shape under the effect of the microenvironment.     

运动训练对大鼠主动脉应力和NF-κB及c-fos表达的影响

目的：探讨不同强度运动训练对大鼠主动脉应力和NF-κB及c-fos表达的影响。方法：采用跑台训练方式,建立大鼠有氧运动和疲劳运动模型,运用免疫组织化学SABC法研究不同强度运动训练对大鼠主动脉VEC和VSMC中NF-κB及c-fos表达的影响。结果：胸主动脉血压的变化与对照组比较,有氧训练和疲劳训练均显著性升高（P〈0．05）,但有氧训练与疲劳训练之间差异不显著。与对照组比较,有氧训练大鼠VEC和VSMC中NF-κB和c-fos均显著性下调表达,胸主动脉张开角显著性升高（P〈0．05）,疲劳训练大鼠VEC和VSMC中NF-κB和c-fos均显著性上调表达（P〈0．05）。与有氧运动组比较,疲劳运动大鼠VEC和VSMC中NF-κB和c-fos表达与胸主动脉张开角升高均具有显著性差异（P〈0．05）。表明不同强度运动大鼠主动脉VEC中NF-κB和c-fos表达变化趋势不同,疲劳训练组表达的增加趋势更显著。结论：运动可引起大鼠主动脉VEC和VSMC NF-κB及c-fos表达的变化,且与运动强度关系密切。有氧训练引起的慢性剪切应力变化可使主动脉VEC和VSMC NF-κB加及c-fos显著性下调表达,与VEC和VSMC维持血管功能的稳态有关;疲劳训练可导致壁面摩擦剪切力、周向应力增加,过度的剪切力作用可引起主动脉VEC和VSMC NF-κB及c-fos显著性上调表达,血管张开角显著增加,血管发生非均匀生长,引起血管结构与功能的重塑。     

Accumulation of calcium and phosphorus in the mitral valve in comparison with the abdominal aorta and the scaphoid bone

To clarify why calcification of the mitral valve occurred, the authors chose the abdominal aorta and the scaphoid bone among many arteries and bones, and they studied both relationships in element contents between the mitral valve and the abdominal aorta and between the mitral valve and the scaphoid bone. The subjects consisted of 11 men and 8 women, ranging in age from 52 to 96 yr. The accumulation of calcium and phosphorus occurred progressively with aging in the mitral valve, whereas it became the highest in the sixties in the abdominal aorta and did not increase thereafter. The accumulation of calcium and phosphorus occurred in the abdominal aorta earlier than the thoracic aorta, in which it became remarkable in the seventies. It should be noted that in regard to the accumulation of calcium and phosphorus, no significant correlations were found between the mitral valve and the abdominal aorta. It is suggested that calcification of the abdominal aorta is not essentially accompanied by calcification of the mitral valve. The scaphoid bone was chosen among many bones consisting mainly of spongy bone and the relationship was examined between the calcium content in the mitral valve and the bone mineral density of the scaphoid bone. It was found that there was a low relationship between them. Therefore, it is suggested that a part of the surplus calcium released from bones is deposited in the mitral valve.     

Protein remodeling of the heart ventricles in hereditary hypertriglyceridemic rat: effect of ace-inhibition

The aim of this study was to determine whether protein remodeling of the heart ventricles and remodeling of the aorta were present in hereditary hypertriglyceridemic (hHTG) rats and whether treatment with the angiotensin-converting enzyme inhibitor, captopril could prevent these alterations. Three groups of rats were investigated in a four week experiment control Wistar /C/rats, hHTg rats, hHTg rats given captopril (100 mg/kg/day) (hHTg + CAP). In the hHTg group, the increased systolic blood pressure (SBP) was associated with hypertrophy of the LV and RV. Protein profile analysis revealed an enhancement of metabolic protein concentration in both ventricles. The concentration of total collagenous proteins was not changed in either ventricles. However, alterations in composition of cardiac collagen were detected, characterized by higher concentration of hydroxyproline in pepsin-insoluble fraction and lower concentration of hydroxyproline in pepsin soluble faction in the LV. Hypertrophy of aorta, associated with the reduction of nitric oxide dependent relaxation, was also present in hHTG rats. Captopril normalized SBP, reduced left ventricular hypertrophy (LVH), diminished metabolic protein concentration in both ventricles, and improved NO-dependent relaxation of the aorta. Furthermore, captopril partially reversed alterations in hydroxyproline concentration in soluble and insoluble collagenous fractions of the LV. We conclude that hypertrophy of both ventricles and the aorta are present in hHTG rats, along with protein remodeling of both ventricles. Captopril partially prevented left ventricular hypertrophy development and protein remodeling of the myocardium.     

Plasma catecholamines in the aorta and the phrenicoabdominal vein in exercising dogs

Plasma epinephrine and norepinephrine concentrations were measured in the aorta and phrenicoabdominal vein in five dogs at rest and during short-duration mild- and moderate-intensity exercise and during prolonged mild-intensity exercise. Plasma epinephrine and norepinephrine concentrations increased with exercise in both the aorta and the phrenicoabdominal vein. Plasma epinephrine concentration was much higher in the phrenicoabdominal vein than in the aorta (24-43 times). Plasma epinephrine concentrations in the aorta and phrenicoabdominal vein were significantly correlated (r = 0.88). This confirms that peripheral epinephrine concentration is a reliable index of the activity of the adrenal medulla during exercise. The epinephrine-to-norepinephrine ratio in the phrenicoabdominal vein was stable (4:1) throughout the experimental protocol, suggesting that the proportion of the two amines released by the adrenal medulla did not vary through this range of adrenal activity in dogs.