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Biomedical subjects

D B Olsen

Publications and source records attributed to D B Olsen.

At least 109 records · Page 6Linked to original sources
PubMed1986

Bloodpumps.

Explore the source record for details and available documents.

Assisted Circulation↗
PubMed1985

Heparinized polyurethanes: in vitro and in vivo studies.

Heparin immobilization chemistry using alkyl spacer arms was adapted to optimize yield on polyurethane (PU) surfaces. The resultant biological activity of immobilized heparin (HI) was examined in vitro and in vivo, and compared with a heparin releasing (HR) system. Immobilized heparin retained its ability to bind and inactivate thrombin and Factor Xa; nonspecific coagulation factor binding was insignificant. Such activity cannot be attributed to the leakage of improperly bound heparin. Immobilized heparin-polyurethane catheters implanted in canine femoral and jugular veins for 1 h periods exhibited significant reduction in thrombus formation compared with untreated PU contralateral controls. Polyurethane catheters coated with a 9% heparin dispersion in PU (HR) system provided even greater improvement in antithrombogenicity.

Animals↗
PubMed1985

Plasma growth hormone response to synthetic GH-RH1-44 in 52 children and adults with growth hormone deficiency of various etiologies.

52 patients (42 children and 10 adults) with growth hormone deficiency (GHD), grouped into four diagnostic categories, and 6 children with constitutional short stature who served as controls were tested for plasma GH response to synthetic GH-RH1-44 given in an intravenous bolus. The response was classified into three degrees according to the magnitude of the maximal rise: Good, greater than 9 ng/ml; Partial, 3.1-9.0 ng/ml; None, less than or equal to 3 ng/ml. Among the GHD patients the highest response was observed in patients with partial growth hormone deficiency (PGHD), and 60% of the children with isolated GH deficiency (IGHD) showed an increase in plasma GH levels. Nevertheless, the response of the GHD patients was lower than that in the control group. In the children and adolescents with PGHD and IGHD the response was not age related. Among those with multiple pituitary hormone deficiencies-idiopathic (MPHD-ID) there was no response in the adolescents although a hypothalamic disorder had been documented by other tests. Among those with MPHD-organic (MPHD-ORG) the GH-RH stimulated GH secretion in the patients with glioma, who had received only irradiation treatment, and in the youngest of the patients with craniopharyngioma. Of the 10 young adults tested none showed a good response. It is concluded that GH-RH is useful in differentiating between GH deficiency of hypothalamic origin and that of pituitary origin, and in selecting those patients who might benefit from long-term treatment with GH-RH in the future.

Adolescent↗
PubMed1985

Comparative hematological data from animals implanted with a total artificial heart containing different valves.

A review of animals receiving a TAH with 4 mechanical valves suggests that the least damage to the blood cell components is associated with the BS valve when compared with the MH valve at similar heart rates. Clinical anemia in varying stages was observed in most animals in this study. However, most calves compensated for the increased rate of hemolysis and none required blood transfusions. The BS valve would appear to combine minimal turbulence and mechanical crushing in a physiological setting.

Animals↗
PubMed1985

Management of a malfunctioning left ventricle in an artificial heart.

Artificial heart research is carried out in the United States, Europe, Japan, Argentina and the Soviet Union, and prolonged survival has been achieved in animals, which has increased the interest of the media and public in this field. Although recent advances are promising, device malfunction remains an obstacle to overcome in most laboratories. Relying on noninvasive monitoring techniques we were able to diagnose and correct artificial heart malfunction safely using surgical techniques employed during the heart implantation.

Animals↗
PubMed1984

Differential diagnosis between hypothalamic and pituitary hGH deficiency with the aid of synthetic GH-RH 1-44.

Synthetic GH-RH 1-44 administered as an intravenous bolus (1 microgram/kg) evoked a marked hGH rise (greater than 20 ng/ml) in three children with constitutional short stature and in two of eight children diagnosed as having hGH deficiency by insulin hypoglycaemia and/or clonidine tests. As judged by the intensity of the hGH response to the dose employed and the peak time, GH-RH 1-44 may be as potent as GH-RH 1-40 in children. It is concluded that GH-RH is an important addition to the endocrine armamentarium, providing the means for differentiation between hypothalamic and pituitary hGH deficiency in a simple test which is devoid of side effects.

Adolescent↗
PubMed1984

A cardiac output monitor and diagnostic unit for pneumatically driven artificial hearts.

The pneumatic artificial heart uses a flexible diaphragm to separate blood from air. The air space behind the diaphragm is connected to the atmosphere during diastole. Blood entering the heart during diastole displaces an equal volume of air into the atmosphere. A pneumotachograph is used to sense this flow of air. Integration of the airflow signal with respect to time yields the volume of air displaced during diastole, which is equal to the volume of blood entering the heart over the same period. This measured filling volume is equal to the cardiac output when averaged over a number of cardiac cycles. Allowance is made for regurgitant losses owing to the prosthetic heart valves. The output of the pneumotachograph is independent of absolute pressure, and so the device may also be used during the systolic (air compression) phase of the cardiac cycle. Analysis of the display of the airflow curves during diastole and systole has great diagnostic value. This device is accurate, easy to calibrate, stable, noninvasive, and does not require modification of any existing air-driven artificial hearts.

Air↗