Biomedical subjects
O Henriksen
Publications and source records attributed to O Henriksen.
Migration inhibition by an agarose microdroplet assay: monitoring of tumor-associated antigens on a simian virus 40-induced sarcoma.
Macrophage migration inhibition assays, with a direct agarose microdroplet method, were used to monitor TAA activity of preparations of SV-40-induced mKSA cells. These preparations included cell-free crude membranes, papain-solubilized and NP40 detergent-solubilized membrane extracts from mKSA tumor cells. The assay was extremely sensitive and could detect migration inhibition reactivity with all three types of antigenic preparations with concentrations as low at 250 ng protein/ml. The reactivities were quite reproducible from experiment to experiment using the same or different lots of these antigen preparations, and the reactivities were specific in that peritoneal exudate cells from BALB/c mice, immunized with antigenically unrelated but syngeneic plasmacytomas, were not inhibited by these antigens. The results demonstrated the usefulness of this assay in rapidly detecting small concentrations of partially purified TAA preparations by using small number of immune cells.
Local sympathetic reflex mechanism in regulation of blood flow in human subcutaneous adipose tissue.
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Comparative chemical analyses of the alloantigenic fragments of HL-A antigens.
Papain-solubilized HL-A antigens have been shown to contain two polypeptide fragments: beta2-micro-globulin with a molecular weight of approximately 12,000 and a larger fragment with a molecular weight of about 34,000. The large fragments isolated from two HL-A preparations carrying different specificities appeared homogeneous both by immunoelectrophoresis and sodium dodecyl sulfate-acrylamide electrophoresis. Both HL-A antigen preparations contained the same NH2-terminal (glycine) and the same COOH-terminal residue (serine). The carbohydrate content of the large fragment was 12.9%, making the carbohydrate-free molecular weight approximately 30,000. Small but significant differences have been found in the amino acid compositions and tryptic peptide maps of the two large fragments containing different specificities.
The component fragments obtained by acid dissociation of papain-solubilized H-2 molecules.
H-2Kk and H-2Dd molecules were specificially purified from a radioiodinated H-2a preparation obtained by papain digestion of spleen cell membranes of A/J strain mice. The molecules were isolated by binding to H-2 alloantisera of the corresponding private specificity followed by precipitation with rabbit anti-mouse IgG antiserum. The specifically precipitated radioiodinated H-2Kk and H-2Dd molecules were dissociated by acid treatment into large and small components of about 37,000 and 11,000 respectively. These were separated by gel filtration at acid pH or by gel isoelectric focusing in the presence of 6 M urea. Each component separated by gel filtration of the acid-dissociated H-2 molecules showed a high degree of size homogeneity as determined by sodium dodecyl sulphate-acrylamide gel electrophoresis. Upon gel isoelectric focusing, however, the small components showed two peaks of radioactivity closely located together at pH 7-8, both of which had a restricted pH range, while the large components gave one peak of a relatively wide pH range of pH 5-6. The H-2Kk and H-2Dd molecules gave essentially the same pattern in terms of the numbers and the positions of the radioactivity bands. Under the iodination conditions used the large components of H-2Kk molecules contained more radioactivity than the small components, while the reverse was true in case of H-2Dd molecules. Such a difference was also found with H-2Kk and H-2Dd molecules isolated by use of alloantisera of the respective public specificity. The assay of binding of the isolated components with H-2 alloantisera of defined specificity revealed that the large components retain most of the allospecificities of the parental H-2 molecules. No H-2 allospecificities were found on the small components. The small components showed extensive binding with rabbit antiserum against mouse beta2-microglobulin. The same antiserum did not show any binding with the large components. On the other hand, both of the components did bind with rabbit antiserum against papain-solubilized H-2 molecules.
Intrinsic regulation of blood flow in adipose tissue.
Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue. Following total ischemia all experiments showed a period with reactive hyperemia, and both duration of hyperemia and excess flow was related to the duration of the ischemia. This response therefore seems more resistant to the experimental procedure, while autoregulation of blood flow to lowered pressure is more susceptible to surgical exposure of the tissue. During elevation of arterial perfusion pressure blood flow in the isolated tissue showed a transient increase and then almost returned to the level during normotension, indicating an elevated vascular resistance. Raising of venous pressure elicited vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (autoregulation), venous pressure and total ischemia appear to be elicited by different mechanisms.
Effect of somaesthetic denervation upon the vasoconstrictor response in human subcutaneous tissue.
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Effect of chronic sympathetic denervation upon local regulation of blood flow in human subcutaneous tissue.
The effect of chronic sympathetic denervation upon the vasoconstrictor response to an increase of vascular transmural pressure in human subcutaneous adipose tissue was investigated in 6 patients suffering from manual hyperhidrosis. Changes in transmural pressure were obtained either by postural changes of a forearm or by venous stasis of 30 mmHg. Blood flow was measured in the distal part of the forearm or crus by means of the local 133Xenon washout technique. 2 patients were studied before and after sympathectomy. When the area under study was lowered about 40 cm below the jugular notch, blood flow decreased about 50% preoperatively, about 30% 24 h after the operation, but remained constant 4 days after or later. Similar results were obtained during venous stasis. Hence about 4 days after sympathectomy, the vasoconstrictor response to an increase in vascular transmural pressure was abolished. In 3 chronically sympathectomized patients blood flow remained constant in the denervated limb, but decreased significantly in the control limb. In another patient studied 580 days after surgery blood flow remained constant during lowering of the denervated forearm as well as during venous stasis. These findings might indicate that the vasoconstrictor response to an increase in vascular transmural pressure in human subcutaneous adipose tissue is due to a local nervous mechanism involving symphathetic adrenergic nerves, but a myogenic mechanism cannot be definitively excluded.
Local nervous mechanism in regulation of blood flow in human subcutaneous tissue.
The effect of local venous stasis upon blood flow in human subcutaneous adipose tissue on the distal part of the forearm was investigated in three healthy subjects and two chronically sympathectomized patients suffering from manual hyperhidrosis. The area under study was separated into two parts by means of a lead shield exerting a pressure of about 360 mmHg on the skin. The effect of venous stasis of about 40 mmHg on one side of the shield upon blood flow measured simultaneously on both sides of the shield by the local 133Xenon washout technique was investigated. During venous stasis on one side of the shield, blood flow decreased about 40% on both sides. The vasoconstrictor impulse could be transmitted over a distance of about 1-2 cm. The phenomenon was unaffected by nerve blockade induced 3 cm proximally, medially, and laterally to the area by infiltration the skin with lidocaine. Thus a vasoconstrictor impulse could be transmitted from the side of stasis to the non stasis side of the lead shield. The transmission was not affected by phentolamine but was blocked by lidocaine and chronic sympathetic denervation. The vasoconstrictor impulse elicited during venous stasis is therefore most likely transmitted by means of a local nervous mechanism involving sympathetic adrenergic vasoconstrictor fibres.
Local reflex in microcirculation in human subcutaneous tissue.
The effect of changes in transmural pressure in the vessles of the extremities on blood flow in subcutaneous adipose tissue were investigated in three healthy subjects. Changes in transmural pressure were obtained either by postural changes of a limb, by locally induced subatmospheric pressure, or be venous stasis. Blood flow in subcutaneous tissue was measured 10 cm distal to the fibular head and at the lateral malleolus in the leg, or in the distal part of the forearm by the local 133Xenon washout technique. When transmural pressure increased 25 mmHg or more, blood flow decreased about 50 per cent due to an increase in vascular resconstrictor response to increase in transmural pressure could be blocked by infiltrating the area under study with phentolamine or lidocaine or by induced counterpressure. In these cases blood flow remained constant. The findings indicate that the vasoconstrictor response to increase in transmural pressure of 25 mmHg or more is due to a local nervous mechanism involving adrenergic nerves. The receptors are presumably stretch receptors placed in the small veins. The effector site is probably the arterioles. When the vasoconstrictor response is blocked, autoregulation of blood flow in subcutaneous tissue, i.e. maintenance of constant blood flow during changes in perfusion pressure head or during changes in transmural pressure, is revealed. The vasoconstrictor response to increase in transmural pressure will counteract an increase in transmural pressure in the exchange vessles and thereby act as an edema protecting factor.
The absence of fibres in the sural nerve mediating vasoconstriction.
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Some biologic and biochemical properties of soluble tumor antigens.
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Biological and biochemical properties of soluble tumor-specific transplantation antigen of a simian virus 40-induced neoplasm.
We have solubilized by limited papain digestion and partially purified the tumor rejection antigen, tumor-specific transplantation antigens (TSTA), from membranes of a simian virus 40-induced sarcoma. Uniform-sized materials with a molecular weight range of 50,000 have retained their tumor rejection activities through the purification procedures. The simian virus 40 TSTA have been separated from H-2 activity by affinity chromatography on concanavalin A columns and no evidence was found for H-2 antigens in the unbound fraction (I) of concanavalin A containing TSTA activity. A reduced yield from the crude soluble fraction was observed with Fraction I of concanavalin A material and this may indeed represent fragmentation of antigen during papain digestion. These results stand in contrast to purification of histocompatibility antigens (H-2alpha) using the same methods and techniques. Low concentrations of simian virus 40 TSTA crude soluble materials were nervertheless biologically active. A concentration as low as 4 mug protein provided 50% tumor rejection and 0.1 mug protein provided lymphocyte stimulation. Both assays reflected specificity of response.
Tumour rejection properties of solubilised TSTA from an SV40-induced neoplasm.
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Interaction of guanosine nucleotides with elongation factor 2. I. Equilibrium dialysis studies.
Binding of the guanosine nucleotides, GDP and GTP, to elongation factor 2 (EF-2) from rat liver was studied by equilibrium dialysis. It was found that the enzyme has one binding site for GDP with a dissociation constant of 4 times 10--7 M. The examination of GTP binding was difficult due to the simultaneous presence of GDP and GTP even in purified GTP preparations. This problem was further magnified by traces of GTPase in the enzyme preparation. However, by analyzing the incubation mixtures by thin layer chromatography the fraction of the total nucleotide binding to EF-2 which was due to GDP could be determined and corrected for. A GTP binding curve, corrected for GDP binding, and GTP hydrolysis extrapolated to one binding site with a dissociation constant of approximately 2 times 10--6 M. The nonhydrolyzable GTP analogue, theta, gamma-methylene-guanosine-5-triphosphate, also bound to EF-2 in a 1:1 ratio. During the studies of GTP binding to EF-2 it was observed that the enzyme preparation contained a GTP-GDP transphosphorylase activity. It was initially thought that this was a novel property of EF-2, but when the activity was followed during purification of EF-2 it was whown that it was an impurity in the EF-2 preparation. ATP as well as GTP can serve as a phosphate donor in the transphosphorylation reaction; this might suggest that regeneration of GTP from GDP can take place via this pathway.
Interaction of guanosine nucleotides with elongation factor 2. II. Effect of ribosomes and magnesium ions on guanosine diphosphate and guanosine triphosphate binding to the enzyme.
The effects of ribosomes and Mg-2plus on the binding of GDP and GTP to elongation factor 2 (EF-2) have been studied by an improved filter-binding assay. Both ribosomes and Mg-2plus strongly inhibit the binding of GDP but have apparently no effect on the GTP binding to the enzyme. An apparent stimulation by ribosomes of GTP binding to EF-2 is time-dependent and parallels a concomitant increase of the GDP concentration in the incubation mixture. Based on these results and evidence obtained by other investigators it is suggested that changes in the GTP:GDP ratio associated with the elongation and termination reactions of protein synthesis cause conformational changes of the respective factors which consequently will modulate the binding and dissociation of the enzymes from ribosomes. Further evidence of the role GDP may play as a modulator of protein synthesis might possibly be provided by studies of the GTP-GDP transphosphorylase activity which is present as an impurity in highly purified preparations of EF-2 as well as in ribosome preparations. It is demonstrated that relatively high concentrations of GDP in the presence of GTP completely block the ribosome-dependent GTPase activity of EF-2. Instead, the transphosphorylase enzyme(s) catalyzes an exchange reaction between GTP and GDP during which GDP remains bound to EF-2 and the relative concentrations of the two nucleotides do not change.
Proceedings: Elongation factor 2: amino acid sequence at the site of ADP-ribosylation.
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Effect of spinal sympathetic blockade upon local regulation of blood flow in subcutaneous tissue.
The influence of spinal sympathetic blockade upon local regulation of blood flow in subcutaneous adipose tissue was investigated in six subjects. The effect of changes in orthostatic pressure on blood flow in subcutaneous tissue in the crus and distal forearm was measured before and after sympathetic blockade obtained by epidural anesthesia in 4 subjects and by a bilateral sympathectomy in 2 patients suffering from manual hyperhidrosis. Blood flow in subcutaneous tissue measured by 133Xe washout technique decreased by about 40 per cent when the limb was lowered, and remained constant during 30 cm elevation. This was found both before and after the blockade, though in one of the patients, the orthostatic decrease in blood flow was less pronounced 24 h after sympathectomy. Hence central sympathetic reflexes do not alter local orthostatic changes of blood flow in subcutaneous tissue. These changes therefore are most likely due to local mechanisms.