Search PubMed⌕ Search

Biomedical subjects

K Johansen

Publications and source records attributed to K Johansen.

At least 217 records · Page 12Linked to original sources
PubMed1979

The effect of suppressive therapy of nontoxic diffuse goiter on serum levels of thyroxine, 3,5,3'-triiodothyronine and 3,3',5'-triiodothyronine.

We studied the effect of suppressive therapy with graded doses of thyroxine (T4) on serum levels of T4, 3,5,3'-triiodothyronine (T3) and 3,3',5'-triiodothyronine [rT3] in patients with diffuse, nontoxic goiter. For comparison and in order to elucidate the degree of suppression of the pituitary thyroid axis by T3 the effect of suppressive therapy with T3 was studied in the same type of patients. We found that T4 in serum rose significantly to a constant level during T4 treatment (0.10, 0.15 and 0.20 mg/day). Dose-related rises in T4 were only seen after 3 months of treatment. T3 and rT3 only changed minimally. The T4/T3 ratio rose to a constant level during the initial 3 months of treatment. T3/rT3 ratio remained unchanged. No dose-related differences in T4/T3 and T3/rT3 ratio were observed. Treatment with T3 in doses of 0.06 mg per day caused a significant but slow fall in T4 and rT3 to hypothroid levels while T3 only rose slightly. The T4/T3 ratio dropped significantly during T3 therapy.

Adult↗
PubMed1978

Transplant renal artery stenosis occurring in both recipients from a single donor.

Stenosis of the renal artery is increasingly being recognized as a cause of hypertension and renal failure after kidney transplantation. To our knowledge, this is the first report of an almost simultaneous occurrence of this complication in both recipients of kidneys from a single donor. In both cases, surgical correction led to improved renal function and amelioration of the hypertension.

Adult↗
PubMed1978

An O2-Hb "paradox' in frog blood? (n-values exceeding 4.0).

O2-Hb dissociation curves have been determined for the anurans, Rana temporaria and Rana catesbeiana, and compared with human blood for the specific purpose of defining the n-value (hill's cooperativity coefficient) at high O2 saturations. The P50 values at normal conditions (see fig. 1) for each species were 24.6 mm Hg for human blood, 37.0 mm Hg for Rana temporaria blood and 53.5 mm Hg for Rana catesbeiana. For human blood the n-value was 2.7 at saturations from 36% to 98% levelling off at the highest saturations. For Rana temporaria Hill plots between saturations from 20% to 98% showed 3 segments. The average n-value increased from 1.6 to 2.4 at about 50% saturation, increasing again at about 80% saturation to 7.3. The pattern in Rana catesbeiana blood was similar with the n-value changing from 1.6 to 3.1 at about 50% saturation, averaging 3.5 between 53% and 89% saturation. Additionally the Bohr effect in Rana temporaria blood more than doubled when compared at 50% and 90% saturation. The data show that for R. temporaria blood the free energy of interaction associated with the binding of 02 to Hb is displaced to the upper segment of the dissociation curve.

Animals↗
PubMed1978

The preferential role of triiodothyronine in the regulation of basal metabolic rate in hyper- and hypothyroidism.

The free triiodothyronine index (FT3I) was significantly correlated to basal metabolic rate (BMR) in hyperthyroid (r=+0.63, p less than 0.01) and hypothyroid patients (r=+0.61, p less than 0.05). Elimination of the effect of the free thyroxine index (FT4I) on the total correlation between BMR and FT3I by partial correlation analysis gave partial r=+0.60, p less than 0.01 in hyperthyroid patients and partial r=+0.43, p less than 0.1 in hypothyroid patients. The FT4I did not correlate to BMR in either hyper- or hypothyroid patients. These results point to triiodothyronine as the major regulator of BMR in hyper- and hypothyroidism.

Basal Metabolism↗
PubMed1978

Myxoedema and thyrotoxicosis: relations between clinical state and concentrations of thyroxine and triiodothyronine in blood.

The clinical manifestations in thyrotoxic and myxoedematous subjects were assessed by clinical diagnostic score indices and related to the free thyroxine index (FT4I) and the free triiodothyronine index (FT3I), basal metabolic rate (BMR) and in the hypothyroid patients to serum thyrotropin (TSH) level. The clinical score index was significantly correlated to both FT4I and FT3I in both groups of patients. No difference existed in degree of correlation between the clinical score index, on the one hand, and FT3I and FT4I, on the other, in either thyrotoxic or myxoedematous subjects. The degree of correlation between clinical score index and FT3I and FT4I was higher than that between the thyroid hormones and BMR. The clinical score index thus appears to be a better indicator of severity of hyper- and hypothyroidism than BMR. Serum TSH concentration was not correlated to the clinical state.

Adult↗
PubMed1978

Factors governing insulin and glucagon responses during normal meals.

An experimental model is described which can be used to study substrate and hormone responses to normal meals administered in very near normal circumstances. After 500, 300 and 125 calorie meals, the relative proportion of fat or protein content did not influence the plasma glucose except for minor differences between the high protein-high fat meals. The insulin response to such meals was correlated positively with the increment in glucose but reduction of protein content below 8 g caused a signficant reduction in the increment in plasma insulin per unit increase in plasma glucose. Alterations in protein content above 8 g made no difference. Fat content of the meal did not significantly alter the insulin response. No evidence was obtained for a major component of insulin release attributable to either bulk or preabsorption phenomena such as sight or smell. It is concluded that a significant accentuation of the insulin response to meals is dependent on a minimum amount of protein and that this is probably mediated by one of the gastro-intestinal hormones. Glucagon release is dependent on protein and carbohydrate content of the meal and is independent of the fat content. There may also be an early stimulation of glucagon release, regardless of content, which may also be hormonally mediated.

Adult↗
PubMed1978

Myocardial inotrophy of CO2 in water- and air-breathing vertebrates.

A negative-inotropic effect of CO2 on myocardial contractility presumably occurs because increasing H+ concentration competes with Ca2+ at cellular membranes and proteins. Since air-breathing vertebrates have higher blood and tissue CO2 concentration than water breathers the question was raised whether the cardiac cell has a modified sensitivity to CO2 correlated with the evolutionary transition of vertebrates from water breathers to air breathers. The water-breathing fish, Salmo gairdneri, and the air-breathing turtle, Pseudemys scripta, were selected as experimental animals, since their total CO2 concentration differs markedly (3.0 and 16.0 mmol.kg-1). Electrically paced isometric ventricular strips from both species were subjected to a stepwise increase in PCO2 from 25 to 114 Torr (pH0 7.80 to 7.0; HCO3- 30 mM). Trout were additionally exposed to the same pH0 changes at 5 mM HCO3- by a stepwise increase in PCO2 (4.5-12 Torr). At each increase in PCO2 the turtle heart showed a lesser negative inotropic effect than trout. The present findings offer direct evidence that the negative inotropic effect of CO2 on heart muscle is inversely proportional to the in vivo levels of tissue CO2 concentration. The results obtained are discussed in relation to phylogenetical and ecological aspects of acid-base balance.

Animals↗
PubMed1978

Ventilation in an aquatic and a terrestrial chelonian reptile.

1. Periods of breath-holding are interrupted by episodes of continuous breathing in the aquatic turtle Pelomedusa subrufa, whereas single breaths and short periods of breath-holding alternate in the terrestrial tortoise Testudo pardalis. This implies that partial pressures of O2 and CO2 in expired air are stable in Testudo in contrast to cyclic fluctuations in Pelomedusa. 2. In spite of this, air convection requirements (VA/VO2, ml BTPS/ml STPD) are not significantly different for the two species (25.4 in Testudo, 27.3 in Pelomedusa), and differences in weight-specific ventilation between the mean body weight. 3. The end-tidal PCO2 in Pelomedusa (mean 15.2 mmHg) is lower than in Testudo (mean 24.7 mmHg), which reflects aquatic CO2 elimination in Pelomedusa. 4. In Testudo, the time course of ventilation correlates with the time course of increase of end-tidal PCO2 during CO2 breathing, but no simple relationship is evident between ventilation and blood PCO2 in Pelomedusa. 5. In both species tidal volume as well as respiratory frequency increase approximately in proportion to the end-tidal PCO2, although the response to 6% CO2 breathing could be less than expected from extrapolation of the responses to 2 and 4% CO2. Both species also increase ventilation during hypoxia, but hyperoxia depresses ventilation.

Animals↗
PubMed1978

The relationship between levels of thyroid stimulating hormone and of thyroxine and triiodothyronine in blood of hypothyroid patients.

Serum TSH values and the free concentration of T4 and T3 in serum expressed as the free T4- and T3-indices showed a curvilinear relationship in 24 patients with manifest hypothyroidism mainly due to extremely elevated serum TSH levels associated with very low thyroid hormone levels. The same degree of negative correlation was found between the log serum TSH concentration and serum free T4-index (r = -0.51, P less than 0.05) and between log serum TSH concentration and serum free T3-index (r = -0.47, P less than 0.05). The correlation coefficients dropped to non-significant levels when the interdependence between the free T3- and T4-indices was taken into account and eliminated by partial correlation analysis. The degree of negative correlation between serum TSH and the thyroid hormones was also of the same order of magnitude in 5 hypothyroid patients studied prosepctively during treatment with L-thyroxine (TSH vs. T4: mean r = -0.71; TSH vs T3: mean r = -0.79).

Female↗
PubMed1977

Oxygen-binding properties of hemoglobins from estivating and active African lungfish.

The oxygen-binding characteristics and the multiplicity of the stripped hemoglobiin from active lungfish Protopterus amphibius, are the same as in specimens that have been estivating for about 30 months, showing that alteration in the hemoglobin molecules is not involved in the earlier reported increase in oxygen affinity of whole blood during estivation (Johansen et al., '76). At pH 7.0 and 26 degrees C the hemolysates show a high oxygen affinity (P50 = 3.1 Torr), a Bohr factor (delta log P50/delta pH) of - 0.33, and a cooperativity coefficient (n) of 1.7. Between 15 and 26 degrees C, the apparent heat of oxygenation (delta H) is - 8.6 Kcal-mole-1 at pH 7.0, corresponding with data for other fish. A low sensitivity of oxygen affinity to urea appears to be adaptive to the high urea concentrations in estivating lungfish. The salt sensitivity is, however, similar to human hemoglobin. The hemoglobin consists of two major (electrophoretically anodal) components, which differ slightly in oxygen affinity but are both sensitive to pH and nucleoside triphosphates (NTP). Guanosine triphosphate (GTP), the major erythrocytic organic phosphate, however, depresses the oxygen affinity of the composite and separated hemoglobins more effectively than ATP suggesting that GTP is the primary modulator of oxygen affinity. Comparative measurements reveal only one major hemoglobin component in P. annectens which has a markedly lower oxygen affinity and phosphate sensitivity than P. amphibius hemoglobins and thus seems less pliable to phosphate-mediated variation in oxygen affinity. The data are discussed in relation to the hemoglobin systems of other fish.

Adaptation, Physiological↗
PubMed1977

Training and exercise change respiratory properties of blood in race horses.

Effects of training and exercise on blood respiratory properties were investigated in standard-bred race horses. Training caused an increase in the circulating O2 capacity at rest from 18.4 to 21.0 vol%, and in the O2 capacity during exercise from 24.9 to 30.3 vol%. An increase in the in vitro oxygen affinity [P50(PH 7.4, 37.9 degrees C)] of about 2 mm Hg correlated with a decrease in the red cell concentration of 2,3-diphosphoglycerate (DPG) from 6.35 mM-1-1(E), erythrocytes. Trained horses also showed an acute lowering of the red cell DPG concentration after maximal exercise. The physiological significance of the increases in O2 capacity and O2 affinity are discussed and a hypothesis presented to explain the possible relationship between changes in spleenic size, total red cell volume and red cell DPG concentration.

Animals↗