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Biomedical subjects

A Bernhard

Publications and source records attributed to A Bernhard.

135 records · Page 8Linked to original sources
PubMedDate not supplied

A new device for slow progressive narrowing of vessels.

The purpose of this work was to develop a device which allows slow progressive banding of a great artery in infants within 4 to 5 weeks. Employed was the hygroscopic casein ameroid. When brought in contact with fluids, an ameroid cylinder expands characteristically. An early phase of fast expansion proceeds gradually to a phase of slow growth. Size, shape, and encasement of ameroid as well as temperature and type of surrounding fluid modify but do not alter the typical pattern of expansion. The developed constrictor (weight: 5.8 kg, length: 18 mm, diameter: 12 mm) includes a stainless steel socket containing an ameroid cylinder (length: 8.5 mm, diameter: 8 mm). The expanding ameroid pushes a piston with a concave extension (makrolon) a maximum of 2 mm against the artery, which is fixed to the metal housing by a teflon band (width: 4 mm, thickness: 0.5 mm). The band runs in 2 fitting grooves on the metal housing to which it is fixed by a metal ring with a precisely manufactured internal thread allowing exact tightening and loosening of the band around the artery. Utilization of inert materials like teflon, makrolon, and stainless steel warrants experimental and possibly clinical application of the developed small constrictor.

Constriction↗
PubMedDate not supplied

Response of the right ventricle to progressive pressure loading in pigs.

The purpose of this study was to determine the speed and duration of progressive pressure loading of the right ventricle to systemic pressure levels, which allows right ventricular adaptation without myocardial impairment at rest. In 8 pigs with an average weight of 22 kg progressive right ventricular pressure loading of different speeds and durations was induced with a newly developed constrictor. Pressures in the right atrium, right ventricle, and pulmonary artery as well as angiocardiographic volume parameters of the right ventricle were determined weekly over a period of 4 to 7 weeks. A fast progressive right ventricular pressure increase of 3.4 mm Hg/day during 3 weeks was associated with a 20-30% reduction of ejection fraction and a 100% increase of the end-systolic volume. Increase of end-diastolic pressure was 3 to 5 fold. A slow progressive pressure increase of 1.5 to 2.2 mm Hg/day to 100 mm Hg within 4 to 5 weeks was associated with an increase of the end-diastolic pressure to a level observed in systemic ventricles, while change of ejection fraction and end-systolic volume was minimal. The faster the increase of right ventricular pressure the flatter was the peak systolic pressure/end-systolic volume relationship. It is concluded that in contrast to sudden and fast progressive increase of afterload slow progressive increase of afterload to systemic levels does not impair right ventricular myocardial function.

Animals↗
PubMedDate not supplied

Dimensions of the great arteries, semilunar valve roots, and right ventricular outflow tract during growth: normative angiocardiographic data.

Systolic and diastolic diameters of the right and left pulmonary arteries (RPAD, LPAD), descending thoracic aorta (DTAD), right ventricular infundibulum (RVID), and pulmonary and aortic valve roots at the proximal, commissural and distal levels were estimated from angiocardiograms in 24 infants, children, and adolescents without heart disease, and correlated with body surface area (BSA), stroke volume (SV), cardiac output (CO), and ventricular volumes. The relationships between cardiovascular diameters and BSA were better expressed by a power function than by the other functions tried. We obtained different exponents for pulmonary and aortic valve annuli and the more distally measured great arteries (RPAD, LPAD, and DTAD), suggesting different growth patterns. The right ventricular infundibular shortening fraction (RVISF) was weakly correlated with BSA (r = -0.328), and the values obtained indicated constancy during normal growth. There was a direct proportional relationship between the pulmonary valve annulus diameter and the cube root of the right ventricular volume (r = 0.952), as well as between SV and cross-sections of the right pulmonary artery (RPAC; r = 0.916), left pulmonary artery (LPAC; r = 0.878) and descending thoracic aorta (r = 0.962). RPAC and LPAC were strongly correlated (r = 0.940), the RPAC being significantly larger than the LPAC.

Adolescent↗
PubMedDate not supplied

[Foster care for adolescents with severe psychic disorders].

An introduction to the concept and practical implementation of a project entitled "Care in families for young people with mental disorders" is presented. In a project five adolescents were placed in fostering families. Continuous care is provided by a professional family care team and the treatment as out-patients at the Department of Child und Adolescent Psychiatry and Psychotherapy, in which they were previously treated, is continued.

Adolescent↗
PubMedDate not supplied

Aortic valve reconstruction in Rubinstein-Taybi-syndrome: the valuable aid of transesophageal echocardiography.

A fourteen year old boy with Rubinstein-Taybi-syndrome presented with a severe congenital subvalvular fibrous aortic stenosis with associated aortic regurgitation. Transthoracic echocardiographic imaging and left heart angiography showed a transvalvular peak systolic pressure gradient of 90 mmHg and a regurgitant fraction of 30%. The surgical treatment consisted of resection of the subvalvular fibrous tissue and subsequent aortic valvuloplasty. Intraoperative transesophageal echocardiography revealed a wide systolic opening of the aortic valve and good coaptation of the aortic valve leaflets in diastole. Two-dimensional color-coded and contrast echocardiography were successfully used to confirm a satisfactory reconstruction. Transesophageal echocardiography therefore represents a valuable tool in the assessment of the morphologic and haemodynamic status, especially in rare cases of congenital heart disease in older children.

Adolescent↗
PubMedDate not supplied

Heart, lung and heart-lung transplantation in rats.

Heart transplantation in rats has been preferentially done using anatomical models of non-working beating hearts, connected either to the neck vessels or to the abdominal aorta and vena cava. This non-physiological approach results in an altered coronary perfusion and function. It is unknown if such models influence the immunological response to the graft. Orthotopic transplantation, a desirable procedure in rats, is troublesome to perform due to the difficulties of extracorporeal circulation in small animals. We present here a model of a working heterotopic intra-thoracic heart transplantation functioning as a left ventricular bypass.

Animals↗
PubMedDate not supplied

Time course of lung function and exercise performance after heart transplantation.

To study the time course of exercise performance and the diffusion capacity after heart transplantation, we submitted two groups of patients to graded symptom-limited supine exercise. Patients in group 1 (n = 11) underwent operation 12.9 +/- 7.0 months before the study; those in group 2 (n = 10) underwent operation 53.9 +/- 14.8 months before the study. Respiratory and cardiovascular parameters were evaluated noninvasively at rest, at individual peak exercise, and 10 minutes later with a commercially available Sensormedics MMC 4400 metabolic measurement chart. Short-term survivors exhibited a lower maximum work capacity compared with that of long-term survivors (63.6 +/- 25.9 versus 100 +/- 50 W, p < 0.05), with a concomitant lower terminal heart rate (123 +/- 19 versus 137 +/- 17 beats/min, p < 0.05) that accounts for the lower cardiac output in this group, but statistical significance was not achieved (13.0 +/- 4.6 versus 17.5 +/- 6.3 L/min, not significant). Interestingly, significant differences were also observed for diffusion capacity before exercise (11.9 +/- 4.8 versus 19.3 +/- 7.3 ml/min/mm Hg, p < 0.05). The improvement of the diffusion capacity may be associated with a time-dependent change in the diffusion characteristics of the alveolocapillary membrane.

Azathioprine↗