Search PubMed⌕ Search

Biomedical subjects

J Nowak

Publications and source records attributed to J Nowak.

At least 163 records · Page 9Linked to original sources
PubMed1981

In vivo observations on the lipolytic effect of noradrenaline during therapeutic fasting.

To assess the influence of fasting on the lipolytic effect of catecholamines in vivo noradrenaline (NA) was infused to 15 obese subjects before and after 7 days of fasting. The infusion of 7.5 microgram/min NA for 10 min was associated with a greater lipolytic response during than before fasting, as judged from changes in the plasma FFA and glycerol levels. The hemodynamic effects of NA were similar in both conditions. NA sensitivity was tested by infusing the hormone at an increasing rate from 0.05-2 microgram/min. During fasting, there was a 10-fold increase in the sensitivity to the lipolytic effect of NA, and the NA infusion significantly reduced the mean serum insulin level. Before fasting, the insulin level was constant during NA infusion. The increments in the plasma NA concentration were similar in both conditions. When insulin was infused at a constant rate, and graded NA doses were infused simultaneously, no lipolytic effect of NA at rates of 1 and 2 microgram/min significantly increased the plasma glycerol level. Thus, fasting enhances the lipolytic effect of NA in vivo, and this effect is due to increased sensitivity to NA and also to NA-induced depression of the circulating insulin level.

Adult↗
PubMed1981

Leg haemodynamics during different forms of anaesthesia in patients undergoing reconstructive vascular surgery.

In the present study the effects of three different anaesthetics (halothane, n = 9, enflurane, n = 9, and neurolept, n = 11) on leg circulation were studied during vascular reconstruction with a reversed femoropopliteal saphenous vein bypass graft. Leg vascular resistance showed significant differences between the three anaesthetic groups. Thus, during the pretransfusion period, leg resistance in the neurolept group was significantly higher than in the halothane and enflurane groups, although the blood volume did not differ significantly between the groups. Though leg resistance after blood transfusion decreased significantly more in the neurolept group compared with the two other groups, the resistance after transfusion was still significantly higher in the neurolept group. Inducing pharmacological vasodilatation caused significant increases in common femoral arterial and bypass blood flows in all groups, but the increases were significantly more pronounced in the neurolept group. It is concluded that leg haemodynamics are influenced in different ways according to the anaesthetic agents used. This, in turn, might contribute to a better understanding and a more correct interpretation of the results of intraoperative flow and pressure measurements, and, consequently, to improvement of the reconstructive procedure.

Aged↗
PubMed1981

Lack of homology between human and chicken K cells.

Evidence for lack of homology between human and chicken K cells is presented. K cell activity was demonstrated by means of antibody-dependent cell-mediated cytotoxicity (ADCC). It was shown that human lymphocytes do not cooperate with avian antibodies in killing target cells by ADCC mechanism and that chicken lymphocytes do not mediate ADCC with mammalian antibodies.

Animals↗
PubMed1981

Preliminary results of the isolation of chicken FcIgG receptor.

Two methods were used to isolate lymphocyte receptor Fc fragment of chicken IgG salt extraction or detergent solubilization of previously radioiodinated cell membranes. Both crude preparations showed Fc receptor activity, assayed by EA rosette test and by binding to IgG-Sepharose. So far attempts to purify of the receptor by affinity chromatography did not give an active preparation.

Animals↗
PubMed1980

The effect of medial amygdalotomy and anterior hippocampotomy on behavior and seizures in epileptic patients.

In 70 patients with epilepsy and severe behavioural disturbances with EEG changes in the temporal regions, we performed EEG investigations of deep temporal structures, temporal cortex and scalp, using Talairach's stereotactic apparatus. Taking into account the recorded changes we performed 115 stereotactic lesions on the medial amygdala (both unilaterally and bilaterally) and on the anterior hippocampus (cornu Ammonis). The results in epileptic processes were: total recovery in 11.4%, evident clinical improvement in 74.3% and no improvement in 14.3%. Similar results were obtained in behavioural disturbances. Bilateral amygdalotomy and unilateral hippocampotomy in selected cases may produce recovery or amelioration and make possible return to normal social life for epileptic patients with severe behavioural changes.

Adolescent↗
PubMed1980

Cardiac synthesis of prostaglandins from arachidonic acid in man.

The bioformation of PGs in the human heart was studied in 7 male volunteers by constant rate infusion of 14C-labelled arachidonic acid (AA) into the aortic root and simultaneous blood sampling from the coronary sinus. After conventional extraction of lipids from the plasma samples, the various 14C-PGs formed were separated and quantified by means of thin layer chromatography and fractionated liquid scintillation spectrometry. The infused arachidonic acid was metabolized and well defined chromatographic peaks of 14C-PGs were obtained. Apart from a chromatographic peak corresponding to 14C-PG metabolites, 6-keto-PGF1 alpha constituted the main 14C-PG formed (23 +/- 8%) reflecting a considerable synthesis of prostacyclin in the heart. 14C-PGs of the D, E and F series were formed in roughly equal amounts (14--19%). In a 54-year-old subject, 6-keto-PGF1 alpha constituted a greater proportion of 14C-PGs (60%) than in the other subjects. This can reflect a general effect of ageing or it can indicate the presence of ischemic heart disease in this subject.

Adult↗
PubMed1980

Cardiac prostaglandin formation in man.

The quantitative relationship between various prostaglandins (PGs) formed in the human heart was studied by constant-rate infusion of 14C-labeled arachidonic acid into the aortic root and simultaneous blood sampling from the coronary sinus in six healthy volunteers. After conventional extraction procedures, the various 14C-PGs formed were separated and quantitied by means of thin-layer chromatography and fractionated liquid scintillation spectrometry. Most of the arachidonic acid infused was metabolized, and well defined peaks of 14C-PG were obtained in the chromatograms. 6-keto-PGF 1 alpha constituted the main PG formed, reflecting a considerable synthesis of prostacyclin in the heart. PGs of the D, E, and F weries were formed in roughly equal amounts. In a 54-year-old subject, 6-keto-PGF 1 alpha constituted a greater proportion of PG than in the other subjects. This may reflect a general effect of aging or it may indicate the presence of ischemic heart disease in this subject.

Adult↗
PubMed1979

Evidence for an extra-renal origin of urinary prostaglandin E2 in healthy men.

In order to verify the validity of the assumption that male urinary Prostaglandin (PG) E2 reflects its renal production, PGE2 and PGF2 alpha concentrations were measured by radioimmunoassay in the renal venous plasma (RVP) and urine (U) of 12 male and 4 female healthy volunteers. While women had a similar PGE2/PFG2 alpha ratio in RVP (0.59 +/- 0.18) and U (0.41 + 0.06), men and a significantly (P less than 0.05) higher ratio in U (1.43 +/- 1.72) as compared to RVP (0.54 +/- 0.16). This was largely due to considerably higher and more variable U-PGE1 concentrations (roughly 6 times higher than female values), despite almost identical RVP levels. The possibility of an increased U excretion of a cross-reacting member of the PG-system, as a cause of such apparently high PGE2-like immunoreactivity (LI), was ruled out by TLC characterization of PGE2-LI with three different anti-PGE1 sera. Thus, male U-PGE2 may variably reflect an extra-renal source, such as contamination with trace amounts of seminal fluid. It is concluded that, unless such a contamination can be monitored and corrected for, measurement of male U-PGE1 should be considered of questionable relevance to renal PG-synthesis.

Chromatography, Thin Layer↗
PubMed1979

Prostaglandins contribute to the vasodilation induced by nicotinic acid.

The significance of endogenously formed prostaglandins in the vasodilation induced by nicotinic acid (NIC) was investigated. The forearm venous plasma level of radioimmunoassayed PGE (R-PGE) and the forearm blood flow (FBF) were measured in 13 healthy male volunteers at rest and during infusion of NIC. Each subject was subsequently re-studied after pretreatment with the PG synthesis inhibitor, naproxen. In the absence of naproxen, NIC infusion resulted in an almost four-fold rise in the release of R-PGE and a 60% increase in FBF. Pretreatment with naproxen did not affect the basal release of R-PGE or the basal FBF but inhibited both the release of R-PGE and the increase in FBF following NIC. The data support the hypothesis that the vasodilating effect of NIC is largely dependent upon an increased vascular formation of PG.

Adult↗
PubMed1979

Human forearm and kidney conversion of arachidonic acid to prostaglandins.

The capacity of the human forearm and kidney to synthetize different prostaglandins (PGs) was studied, together with the quantitative relationship between the various PGs formed in these organs. 14C-labelled arachidonic acid (14C-AA) was infused in healthy male volunteers at a constant rate into the brachial or the renal artery, with simultaneous sampling of regional venous blood. The venous plasma content of 14C-PGs was extracted, separated with thin-layer chromatography (TLC) and quantified using fractionated liquid scintillation spectrometry. Most of the 14C-AA infused was metabolized and radiopeaks parallel to unlabelled standards of PGD2, PGE2, PGF2 alpha, 6-keto-PGF1 alpha and 13,14-dihydro-15-keto-PGE2 (Me) were obtained. The chromatograms of both the forearm and the kidney plasma contained all the peaks described, but the relative distribution of the 14C-PGs differed between the two tissues. In the cubital venous plasma, the main PG (apart from Me) was 6-keto-PGF1 alpha, indicating a considerable synthesis of PGI2 in the forearm. In the renal venous plasma, on the other hand, PGD2 accounted for the largest part of the authentic 14C-PGs found. Besides the tissue differences, large inter-individual variations were observed. The results demonstrate the existence of both a considerable tissue specificity and an appreciable inter-individual variation in the local conversion of AA to PGs in man.

Adult↗
PubMed1979

A study on the role of endogenous prostaglandins in the development of exercise-induced and post-occlusive hyperemia in human limbs.

The contribution of endogenous PGs to the development of functional (exercise-induced) and reactive (post-occlusive) hyperemia was investigated in healthy volunteers. Leg blood flow during dynamic leg exercise was estimated by an indicator dilution technique. Forearm blood flow during supine leg exercise and forearm and calf blood flow following 5 min of arterial occlusion were measured plethysmographically. All subjects were examined before and after pretreatment with indomethacin, a PG synthesis inhibitor. During leg exercise, and in the absence of indomethacin, a 10-fold rise in leg blood flow was observed. Forearm blood flow increased moderately. Both these blood flow effects of exercise were unaffected by indomethacin. Following arterial occlusion a marked hyperemia developed in the forearm and the calf. Indomethacin significantly reduced the magnitude of the reactive hyperemia both in the forearm and in the calf, decreasing both the peak value and the duration of the vasodilation. These data reveal differences between the mechanisms behind functional and reactive hyperemia in man, suggesting an appreciable contribution of endogenous PGs to post-occlusive vasodilation only.

Adult↗
PubMed1979

Conversion of arachidonic acid to prostaglandins in homogenates of human skeletal muscle and kidney.

The capacity of human skeletal muscle and kidney homogenates to synthetize prostaglandins (PGs) from exogenous precursor was investigated. Low-speed supernatants of muscle as well as renal medullary and cortical homogenates were incubated with 14C-labelled arachidonic acid (14C-AA) prepared as a sodium salt. 14C-PGs in the incubates were extracted, separated with thin-layer chromatography (TLC) and quantified by radioscanning. In the skeletal muscle incubates 14C-AA was converted into 14C-PGs with a time-dependent yield, most effectively after 10--15 min incubation. Well-defined radiopeaks parallel to unlabelled standards of PGD2, PGE2, PGF2 alpha and 6-keto-PGF1 alpha were obtained in the chromatograms. PGE2 was the main PG formed, constituting over 50% of 14C-activity, whereas 6-keto-PGF1 alpha, PGD2 and PGF2 alpha were found in considerably lower proportions. In the renal medullary incubates, PGE2 likewise accounted for the largest part of 14C-PGs formed, but significant relative amounts of PGF2 alpha and PGD2 were also found. A minor peak, corresponding to 6-keto-PGF1 alpha and thus indicating formation of PGI2, was also obtained. In contrast to the medulla, no 14C-PGs could be found in the renal cortical incubates. The results demonstrate the existence of a considerable tissue specificity in the quantitative and qualitative expression of PG biosynthesis in man.

Adult↗
PubMed1979

Esterolytic activity of blood serum in infants with hypertrophic pyloric stenosis.

Esterolytic activity of blood serum was determined in infants with hypertrophic pyloric stenosis and in healthy control children. The substrates hydrolyzed mainly by arylesterase (EC. 3.1.1.2), i.e. p-nitrophenyl esters of acetic, propionic and butyric acid were used. It was found that in infants with hypertrophic pyloric stenosis the rate of p-nitrophenyl propionate hydrolysis was significantly higher than that of the acetate or butyrate. In control group children all three substrates were hydrolysed at similar rates, and these were significantly lower than in infants with hypertrophic pyloric stenosis.

Carboxylic Ester Hydrolases↗
PubMed1979

LEg venous oxygen saturation in the evaluation of intra-operative blood flow during arterial reconstructive surgery.

In twenty-four patients, undergoing a femoro-popliteal saphenous vein bypass graft for symptomatic atherosclerotic occlusion of the superficial femoral artery, oxygen saturation values for the femoral and popliteal veins were compared to the directly measured blood flows in the common femoral artery and in the bypass graft, respectively. Blood flow and venous oxygen saturation increased significantly after transfusion of 900 ml of blood. Pharmacological vasodilation caused a significant increase in blood flow both before and after transfusion, whereas the changes in venous oxygen saturation were significant only before blood transfusion. A close statistical relationship was found between initial femoral venous oxygen saturation and initial blood flow in the common femoral artery as well as between initial popliteal venous oxygen saturation and initial byapss blood flow. However, especially at low saturation values, the evaluation of blood flow was very uncertain. Whole leg and lower leg oxygen uptakes were not altered by intraoperative changes in blood volume. It is concluded that blood flow in the common femoral artery and the bypass graft can be roughly estimated from analysis of oxygen saturation in the femoral and popliteal veins, respectively. Furthermore, by determining leg venous oxygen saturation both before and after flow augmentation, induced by pharmacological vasodilation, a conception of the load on the vascular system may be obtained.

Aged↗