Search PubMed⌕ Search

Biomedical subjects

K Johansen

Publications and source records attributed to K Johansen.

At least 199 records · Page 11Linked to original sources
PubMed1981

Paradoxical saddle embolus: case report with antemortem diagnosis.

The presence of central right-to-left shunt and paradoxical embolism to the aortic bifurcation was suggested by acute aortic occlusion in a young victim of multiple trauma who had several pulmonary emboli. The diagnosis was confirmed by radionuclide and angiographic means and at operation. Paradoxical embolization should be considered in any individual who suffers simultaneous pulmonary embolism and acute arterial occlusion.

Accidents, Traffic↗
PubMed1980

Propylthiouracil in human milk. Revision of a dogma.

Propylthiouracil (PTU) concentrations were measured in blood and milk from nine lactating women after oral administration of 400 mg of PTU. 1 1/2 h after PTU ingestion mean serum-PTU reached 7.7 microgram/ml and the mean concentration of PTU in milk reached only 0.7 microgram/ml. The mean total amount of PTU excreted during 4 h was 99 microgram--i.e., 0.025% of the administered dose. One of the suckling babies was studied for 5 months during which the mother received 200-300 mg of PTU daily: there were no changes in any of the thyroid parameters. PTU is not concentrated in human breast milk and recommended dosages to the mother result in minimal and presumably clinically insignificant doses to the suckling infant.

Adult↗
PubMed1980

Respiratory properties of whole blood and hemoglobin from the burrowing reptile, Amphisbaena alba.

Respiratory properties of whole blood and hemoglobin solutions have been studied in the burrowing reptile, Amphisbaena alba. Whole blood is distinguished from that of other squamate reptiles by an extraordinary high O2 affinity (P50 = 12 mmHg at pH 7.60 and 25 degrees C). The Bohr factor, phi, was large at -0.85 and the n-value was 1.80. O2 capacity averaged 12.0 vol%. The molar concentration of erythrocyte ATP was high and twice that of hemoglobin. Stripped Amphisbaena hemoglobin shows an extremely high O2 affinity and reduced pH sensitivity compared to whole blood (P50 = 1 mmHg at pH 7.60 and 25 degrees C, phi = -0.35, n-value = 2.0). The hemoglobin O2 affinity was much more sensitive to ATP than for other poikilotherm vertebrates. Isoelectric focusing revealed a multicomponent hemoglobin with the major components showing similar O2 affinities and Bohr shifts. The data obtained are discussed in relation to the burrowing habits of Amphisbaena and found to be adaptive to a fossorial mode of life.

Adenosine Triphosphate↗
PubMed1980

Effect of spinal cord temperature on carotid blood flow in the Pekin duck.

Spinal cord heating in white Pekin ducks increases breathing rate and carotid blood flow. During naturally induced panting, the reverse effect was achieved by spinal cooling. An increased beak and expired air temperature during spinal heating suggest an importance of the increased carotid blood flow in maximizing heat dissipation during polypnoea. The results indicate that both the polypneic response and the increase in carotid blood flow are dependent on the same sensory input, namely the temperature of the spinal cord.

Animals↗
PubMed1980

Ventilation and gas exchange in the mute swan, Cygnus olor.

Ventilation and gas exchange have been continuously measured in the mute swan using pneumotachography and breath to breath analysis of the ventilated gas by mass spectrometry combined with blood gas analysis. The breathing frequency was much lower and the tidal volume much higher than values predicted from allometric relations. The breathing cycles typically showed long end-inspiratory breath holding periods. End-tidal PCO2 and PO2 were above and below respectively typical end-tidal gas tensions reported earlier in birds. A pronounced positive PCO2 difference between end-tidal gas and mixed venous blood was present averaging 9.8 mm Hg. The blood-gas values found in the mute swan fall within a range typical of birds. A very low air convection requirement (13.6 ml . ml-1) and high O2 extraction coefficient (33.0%) indicate a high gas exchange efficiency of the swan lung. The unusually large tidal volumes and the long breath holds succeeding each inspiration are likely contributing factors to the high exchange efficiency. Calculated low values for the blood convection requirement (12.8 ml . ml-1) match the low air convection requirements and result in a ventilation/perfusion ratio near unity (VI/Q=1.06).

Animals↗
PubMed1980

Blood flow changes in the duck during thermal panting.

Carotid and sciatic blood flow have been measured in resting and panting Pekin ducks using electromagnetic flowmeters. Panting induced by high ambient temperature caused the carotid blood flow to increase from 9.6 to 26.0 ml min-1, while the sciatic flow declined slightly from 41.6 to 38.1 ml min-1. During panting breathing rate increased 10--20 times, but there were no significant changes in heart rate and mean arterial blood pressure. The carotid peripheral resistance was therefore greatly reduced, whereas sciatic resistance remained unchanged or increased slightly. The vascular beds perfused by the sciatic (legs) and carotid (upper respiratory tract) arteries are both important for heat dissipation. This study shows that when heat dissipation from the naked legs becomes inefficient due to high ambient temperature, blood flow in the sciatic tended to decline while conversely panting was associated with a large increase in carotid flow.

Animals↗
PubMed1980

Ventilatory and circulatory responses to hyperthermia in the mute swan (Cygnus olor).

Ventilatory parameters of mute swans were measured at thermoneutral conditions and during heat stress. Deep body temperature increased from 39.5 to 41.1 degrees C. Breathing frequency increased 29 times, compared to the thermoneutral condition. Tidal volume decreased to 18% of the pre-panting value, and the total ventilatory volume increased by 5.4 times. End-tidal PCO2 and PO2 values decreased and increased, respectively. The swans developed a slight respiratory alkalosis; arterial PCO2 decreased from an average of 27.1 to 25.7 mmHG and arterial pH increased from 7.501 to 7.559. Cardiac output, heart rate and stroke volume were 106%, 154%, and 70%, respectively, of the values at thermoneutrality. Mean arterial blood pressure and total peripheral resistance were slightly reduced. It is concluded that the increased ventilation during panting mainly constitutes dead space ventilation resulting from the great reduction in tidal volume. Parabronchial ventilation remains nearly unchanged, resulting in only a slight hypocapnic alkalosis.

Acid-Base Equilibrium↗
PubMed1980

Treatment of cystinuria with alpha-mercaptopropionylglycine.

Four cystinuric patients (3 females and 1 male) with recurrent L-cystine stone formation were treated with alpha-mercaptopropionyl glycine (MPG). In one patient the treatment was stopped because of a rash developing after one week of treatment. In the other 3 patients MPG was found to be as effective as penicillamine in lowering the urinary cystine excretion to safe levels. No serious side effects of the drug were recorded.

Adult↗
PubMed1980

Trauma to major visceral veins: an underemphasized cause of accident mortality.

In the period 1970-1978, a mortality rate of 44% resulted in 45 patients who suffered major intra-abdominal venous injuries. An especially grave prognosis accompanied wounds to the inferior vena cava and the hepatic and portal venous systems. Management of damage to major veins presents several difficulties. Exposure is poor; veins tear easily when clamped or sutured; exsanguination can occur as rapidly as with arterial trauma; because of low intraluminal pressure, postoperative chances of thrombosis and occlusion are high; veins (unlike arteries) have no intrinsic vasomotor capabilities to halt bleeding. Finally, the misconception persists that venous wounds are less serious than comparable arterial injuries. Simple pressure by packs or hand often controls bleeding: otherwise clamps, balloons, hemostats, or ligation can be selectively chosen. Our experience suggests that atrial-caval shunting without prior identification and control of the bleeding site is doomed to failure.

Abdomen↗
PubMed1979

Periodic breathing in the crocodile, Crocodylus niloticus: consequences for the gas exchange ratio and control of breathing.

The ventilatory pattern in the Nile crocodile consists of episodes of breathing, interrupted by periods of breath-holding, the latter occupying 80% of total time during normal breathing at 25 degrees C. End-tidal gas composition varied with the periodic breathing but PO2 was always high (PO2 less than 110 torr) and PCO2 low (PCO2 less than 25 torr). The alveolar gas exchange ratio, RE, was very low during the non-ventilatory periods (RE congruent to 0.5), but increased markedly during ventilation. Breathing of hypoxic and hpercapnic gases caused a pronounced decrease in the duration of breath-holds. Hypercapnia decreased breathing frequency during ventilatory periods, but increased tidal volume. The results are discussed in relation to the practice of prolonged breath-holding associated with diving in crocodiles.

Alligators and Crocodiles↗
PubMed1979

The relationship between maximal oxygen uptake and glucose tolerance/insulin response ratio in normal young men.

Maximal oxygen uptake (VO2max.), glucose tolerance (K-value), and insulin response (IRI-area) were studied in seventeen young, non-obese, non-diabetic males. The ratio between K-value and IRI-area correlated significantly with VO2 max. (r = 0.70, p less than 0.01) also when differences in body fat mass were eliminated by partial correlation analysis (r = 0.56, p less than 0.05). Subjects with a high VO2 max. thus maintained a given glucose tolerance with a lower insulin response than did subjects in whom VO2 max. was low.

Adipose Tissue↗
PubMed1979

Revascularization of the ischemic canine hindlimb by arteriovenous reversal.

Arteriovenous reversal (AVR) for revascularization of ischemic tissues has previously failed to meet theoretical, experimental, and clinical expectations despite recurrent trials. The efficacy of a new staged approach to AVR was tested against a canine ischemic limb preparation in which global ligation of ipsilateral collaterals inevitably led to limb gangrene. In 12 animals the complications of direct, single-stage end-to-end femoral AVR, inevitably accompanied by the development of extreme edema, were demonstrated. However, when the ischemic preparation was accompanied by a staged AVR, in which an initial end-artery-to-side-vein arteriovenous fistula was converted 1 week later to AVR by ligation of the central venous limb, 20 of 20 animals survived, and 19 of 20 were ambulatory long-term survivors with only mild edema. Serial angiograms at 1 week, 1 month, and 4 months demonstrated patency rates of 100, 84, and 63%, respectively. Histologic examination of animals electively killed from 4 to 24 months showed normal skeletal muscle histology, venous intimal thickening, and mild edema. In the acutely ischemic canine hind limb, a staged AVR can provide both viability and function with only mild edema formation.

Animals↗