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Biomedical subjects

N T Pedersen

Publications and source records attributed to N T Pedersen.

At least 91 records · Page 5Linked to original sources
PubMed1978

Venous air embolism through infusion sets. Theoretical considerations, model experiments and prevention.

Some infusion sets are so designed that, even when infusing into peripheral veins, a negative pressure may occur in a large portion of the infusion tubing, with the result that air enters the system from a side drip which has run dry, or though leaks. In model experiments, it was found that, when infusing into a peripheral vein, volumes of air up to 13 ml per min can enter the system from an empty side drip. From an analysis of the pressure conditions in infusion sets before and during infusion, it is concluded that infusions sets should be so designed that clamps and connections forthe attachment of a side drip are placed distally on the infusion tubing. Even then there is a risk of air embolism. The tubes for both the main and the side drip should therefore be so long that each of them can be fixed below the heart level of the patient, thus forming a waterlock and preventing the entry of air.

Embolism, Air↗
PubMed1978

Megathrombocytopenia associated with glomerulonephritis, deafness and aortic cystic medianecrosis.

Macrothrombocytopenia associated with glomerulonephritis and deafness has only been reported in a few patients since it was first described in 1972. We present a patient with macrothrombocytopenia, glomerulonephritis, progressive uraemia and progressive sensorineural deafness associated with cystic medianecrosis of the ascending aorta and malformation of the aortic valves. The patient had consistently low platelet counts but no clinical signs of a defect haemostasis. The giant platelets were characterized by their size, averaging 11 micron in diameter, elaborate maze-like membrane formations, abundance of microtubules, and the total absence of very dense granules.

Adolescent↗
PubMed1978

Occurrence of megakaryocytes in various vessels and their retention in the pulmonary capillaries in man.

A total of 17 patients with hypertension undergoing renal vein or adrenal vein catheterization were investigated in order to ascertain the number of megakaryocytes in blood from the inferior vena cava, the femoral artery and a cubital vein. On an average 11.9, 3.8, and 4.5 megakaryocytes per ml were found, respectively. In blood from the inferior vena cava, 30% of the megakaryocytes had copious cytoplasm, while megakaryocytes in arterial and cubital venous blood had sparse or no visible cytoplasm. It was demonstrated that 2/3 of the megakaryocytes were retained in the pulmonary circulation and that at least 70% of the platelets could derive from megakaryocytes in central venous blood or the pulmonary circulation. It was found that megakaryocytes pass through a life cycle in which the differentiation take place in the bone marrow, platelet release occurs mainly in central venous blood and in the pulmonary circulation and the destruction of the megakaryocyte nucleus take place outside the bone marrow, especially in the pulmonary circulation.

Adult↗
PubMed1978

Circulating megakaryocytes in blood from the antecubital vein in healthy, adult humans.

A total of 21 healthy, adult men and 30 healthy, adult women aged 21-73 years were investigated for circulating megakaryocytes in the antecubital vein using the saponinhaemolysis leucoconcentration technique. In the males, the number of megakaryocytes in 1.5 ml blood varied from 1 to 20, the arithmetic mean being 10 megakaryocytes. In the females the number varied from 0 to 29 megakaryocytes and the arithmetic mean was 7.6 megakaryocytes. No significant difference was found between the values for the two sexes. There was no correlation between the number of megakaryocytes and platelets or leucocytes. 99% of the observed megakaryocytes were naked nuclei or had sparse cytoplasm and 1% had copious cytoplasm. Megakaryocytes without copious cytoplasm may be regarded as normally occurring cells in the peripheral venous blood.

Adult↗
PubMed1978

Evaluation of painful hip arthroplasty.

The evaluation of chronic pain after hip arthroplasty has always been a difficult problem and recently scintigraphy has been recommended as a suitable method of examination for this purpose. On the basis of radiographic and laboratory studies, scintigraphy, allergy tests, cultures and histological examinations, in 16 patients with chronic pain in the hip after arthroplasty, it is concluded that radiography and scintigraphy together give valuable information about the cause of pain, especially if the prosthesis is infected. Fenestration of the femoral cortex may verify the diagnosis before replacement of the prosthesis.

Arthroplasty↗
PubMed1975

A new preparative method for microspectrophotometric DNA-measurement in megakaryocytes, revealing a significant group of cells with a DNA content of 64 N.

Microspectrophotometric investigations of Feulgen-stained rat bone marrow megakaryocytes, comparing the traditional smear method and a new 1 G sedimentation and 40 degrees C evaporation (S. E.) method, have shown that the latter reveals a significant group of megakaryocytes (ca. 30 percent) with a DNA content of 64 N. This group is totally absent when the smear method is used.

Animals↗
PubMed1975

Hyperparathyroidism and pregnancy. Report of a case and review of the literature.

A 28-year-old gravida III, with a history of two unsuccessful pregnancies, was admitted with hyperemesis gravidarum and was found to be suffering from hyperparathyroidism (HPT). She was treated surgically and was later delivered of a wellformed, premature girl. The literature is reviewed and the histories of 40 females (including the patient of this case report) with a minimum of 93 pregnancies while suffering from HPT shows, that HPT during pregnancy is a serious condition for the fetus as well as for the mother. There was an increased incidence of spontaneous abortion, perinatal death, premature birth and neonatal morbidity. The mothers suffered from increased episodes of renal calculi and hyperemesis gravidarum. The exacerbations nearly always occurred in the first and second trimesters or post partum.

Adult↗