The presence of numerous abnormally arranged cardiac muscle cells in the ventricular septum has been considered a characteristic anatomic feature of hypertrophic cardiomyopathy. However, it has been suggested that the ventricular septum of infants with certain congenital cardiac diseases (such as aortic or pulmonic valve atresia) contains disorganized cardiac muscle cells similar to those in patients with hypertrophic cardiomyopathy. To test the validity of this concept and the true specificity and sensitivity of septal disorganization for hypertrophic cardiomyopathy, sections of ventricular septum were obtained at necropsy from 276 patients and the extent of ventricular septal disorganization was determined quantitatively. Disorganization was most marked in infants, children and adults with hypertrophic cardiomyopathy (i.e., present in 95% of 60 patients); the mean area of septum disorganized was 31 ± 3%. Although disorganized cells were present in 64% of 33 infants with aortic or pulmonic valve atresia, these cells occupied extremely small areas of ventricular septum (mean area of septum disorganized 2.8 ± 0.7%; p < 0.001). Furthermore, the minimal septal disorganization present in aortic or pulmonic valve atresia was similar to that found in 91 infants with other congenital heart malformations and in 92 normal fetuses or infants (mean area of septum disorganized was 1.4 ± 0.6 and 0.3 ± 0.1%, respectively). Hence, extensive ventricular septal disorganization is a highly sensitive and specific finding for hypertrophic cardiomyopathy, although small areas of disorganization may occur in infants with other heart diseases, including aortic or pulmonic valve atresia.
A vibrating flow pump (VFP), which can generate oscillated blood flow (10-50 Hz/min), has been developed by our team for the artificial heart system. However, the flow pattern of this pump was different from that of the natural heart; therefore, it is important to analyze the effect of this oscillated blood flow on the circulatory regulatory system. To analyze the hemodynamics of high frequency oscillated blood flow as an entity, (not decomposed), nonlinear mathematical techniques were utilized. VFPs were implanted between the left atrium in animal experiments using adult goats. After the implantation procedure, the ascending aorta was clamped to constitute the complete left heart circulation with VFP. Using a nonlinear mathematical technique, an arterial blood pressure waveform was embedded into four-dimensional phase space and projected into three-dimensional phase space. The Lyapunov numerical method was used as an adjunct to graphic analysis of the state space. Phase portrait of the attractor showed a high dimension complex structure, suggesting deterministic chaos during natural circulation. However, phase portrait of the hemodynamics during oscillated blood flow showed a single circle with banding and a forbidden zone, similar to a limit-cycle attractor, suggesting a lower dimensional dynamic system. Positive Lyapunov exponent during oscillated blood flow suggests the existence of lower dimensional chaotic dynamics. These results suggest that the circulatory regulatory system during oscillated blood flow may be a lower dimensional homeochaotic state; thus, hemodynamic parameters must be carefully regulated when unexpected external stimuli are present.
Seven adult mongrel dogs with an average body weight of 11.3 kg were subjected to experimental Fontan operation in order to evaluate acute hemodynamic changes at the Fontan circulation. The Fontan circulation was established by occlusion of the tricuspid valve with tightening a purse-string suture which was placed around the valve under inflow occlusion and was passed through the anterior right atrial wall, and by connection with a 10 mm Gore-Tex graft between right atrium and pulmonary artery. When the Fontan circulation was established, aortic pressure and cardiac output (CO) decreased from 94.9 + 22.0 mmHg to 41.9 + 6.0 mmHg and 0.907±0.179 liter/min to 0.259±0.072 liter/min, respectively. There were no significant changes in heart rate and systemic vascular resistance between normal and the Fontan circulations. On the other hand, pulmonary vascular resistance (PVR) increased from 11.6±7.3 units in the normal circulation to 21.8± 13.0 units in the Fontan circulation. From this study it was concluded that main changes in hemodynamic parameters immediately after establishing the Fontan circulation were marked decrease in systemic arterial pressure and CO, and an increase in PVR. Therefore, one should consider a possibility of an increase in the PVR to the critical level when the Fontan operation was applied to patients with pulmonary hypertension. Fontan operation; tricuspid atresia ; pulmonary hypertension Fontan operation has been widely performed in many complex cardiac anomalies including tricuspid atresia, univentricular heart or hypoplasia of the right ventricle since the first report in 1971 (Fontan and Baudet). Although surgical indication for the Fontan operation had been tightly set by Fontan's Ten Commandment (Choussat et al. 1978) initially, recently the procedure has been challenged successfully in patients even with pulmonary hypertension greater than 20 mmHg of mean pulmonary artery pressure or with pulmonary vascular
Laparoscopic cholecystectomy (LC) has become one of the options for the treatment of acute cholecystitis as surgeons gain facility with this procedure. However, acute suppurative cholecystitis is still a severe condition, because a high mortality rate still exists. In the early years (1991 to 1992), 4 patients were operated on without a preceding percutaneous transhepatic gallbladder drainage (PTGBD) at our hospital, however, one patient died of septic shock after a laparoscopic cholecystectomy. Conversion to open surgery was performed on two patients. However, in later years (1992 to 1995), 14 patients were operated on with preceding PTGBDs safely. Here, we report the safeness and significance of the combination therapy of PTGBD and LC for patients with severe acute suppurative cholecystitis.
The importance of the surf zone as a nursery ground for larval and juvenile fishes has been widely recognized, however the zone has yet to be studied in Mauritius. Recently, the coastal area of the island has been increasingly affected by human activities, especially by tourism. We collected fish samples with a hand pulled seine net during the period of August 2001 to March 2003 to clarify the fish fauna and the dynamics of fishes in the surf zone. Two sampling sites adjacent to river mouth areas and one sampling site adjacent to a mangrove area were selected for comparison of fish fauna in relation to environmental conditions. A total of 9,429 fish larvae and juveniles, representing at least 112 species from 48 families were collected. The abundant species were hardyhead silverside, Atherinomorus lacunosus, bluespot mullet, Valamugil seheli, and Ambassis spp., each contributing 16.2, 12.4, and 11.8% of the total number of individuals, respectively. Estuarine species dominated in the surf zone adjacent to the river mouth areas. Species composition and diversity changed seasonally. The number of fish increased during the rainy season. Species diversity increased at the turn of the seasons from the dry season to the rainy season. We conclude that species composition in each site was affected by environmental factors, such as the scale of the flux from the rivers, which is related to the precipitation. The results indicated that freshwater from the river is a trigger to aggregate larvae and juveniles in the surf zone.
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