Biomedical subjects

E Eriksson

Publications and source records attributed to E Eriksson.

At least 253 records · Page 14Linked to original sources

PubMed1988

Tissue plasminogen activator and its inhibitor following major surgery in relation to ventilatory pattern.

Based on animal data it has been hypothesised that lungs may regulate systemic fibrinolysis. To test this hypothesis 12 patients undergoing infrarenal aortic reconstruction due to arteriosclerotic disease were evaluated for influence of the respiratory pattern on release of tissue plasminogen activator (t-PA) and its inhibitor (PAI) in systemic and pulmonary arterial blood. Blood samples were drawn simultaneously from the pulmonary artery and a radial artery at defined times before and during surgery. Samples were also collected during application of positive end expiratory pressure (PEEP) of 5, 10 and 15 cmH2O. The blood samples were analysed for euglobulin clot lysis time (ECLT), t-PA activity, t-PA antigen and PAI. ECLT was not altered during surgery and t-PA activity was below the detectable limit. Before surgery t-PA antigen was 14.5 +/- 1.3 ng/ml and PAI 15.1 +/- 2.8 U/ml (mean +/- SEM). PAI was significantly elevated at end of surgery. There were no differences between samples from systemic and pulmonary arteries. Following application of 5, 10 and 15 cmH2O PEEP the fibrinolytic parameters were unchanged. Thus, in the present study on arteriosclerotic patients undergoing abdominal aortic reconstructions no influence from the respiratory pattern on systemic fibrinolysis could be demonstrated.

Aged↗

PubMed1988

Experimental pretransfer expansion of free-flap donor sites: I. Flap viability and expansion characteristics.

Expansion of cutaneous and myocutaneous free-flap donor sites prior to elevation is possible in the pig model. There is no significant difference in survival between control and expanded cutaneous buttock and myocutaneous latissimus dorsi flaps after elevation solely on their axial pedicles. Axial-pattern flap expansion appears to augment capillary blood flow. The maximum amount of expansion occurs directly over the center of the expander and decreases toward the periphery. There is virtually no expansion of skin adjacent to the expander.

Animals↗

PubMed1987

The intrinsic activities of the partial dopamine receptor agonists (-)-3-PPP and TDHL on pituitary dopamine receptors are lower in female than in male rats.

The abilities of the mixed agonists/antagonists on dopamine (DA) receptors, (-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine [-)-3-PPP) and transdihydrolisuride (TDHL), to suppress serum prolactin levels in acutely hyperprolactinemic male and female rats were investigated. gamma-Butyrolactone was used to deplete endogenous DA and raise serum prolactin concentrations. Both (-)-3-PPP and TDHL were found to cause sexually differentiated responses: (-)-3-PPP reduced serum prolactin levels dose dependently and effectively in males but caused only a modest decrease of prolactin release in females. Moreover, (-)-3-PPP antagonized the prolactin-suppressing effects induced by the DA receptor agonist (+)-3-PPP in females. Likewise TDHL decreased prolactin secretion markedly in males while it had only slight effects in females. It can be concluded from these results that the intrinsic activities of the partial DA agonists (-)-3-PPP and TDHL are lower in female than in male rats, suggesting a reduced responsiveness of hypophyseal DA receptors in females. Since DA levels in the pituitary portal circulation are higher in female than in male rats, this study gives further support to the hypothesis claiming an inverse relationship between the intrinsic activity of a mixed agonist/antagonist and the degree of previous stimulation of its receptor.

Animals↗

PubMed1987

Depletion of natural killer cells in mice by monoclonal antibody to NK-1.1. Reduction in host defense against malignancy without loss of cellular or humoral immunity.

Weekly injections of a monoclonal antibody (MAb) to the antigen NK-1.1 were used to sustain depletion of NK cells from the spleens of adult C57BL/6 mice for up to 8 wk. Mice depleted of NK cells in this manner had no lasting alteration in the distribution of other lymphocyte subsets in the spleen and did not demonstrate reduced cellular or humoral immunity. Depletion of NK cells, however, markedly increased the localization and growth of B16 melanoma cells or CT 38 colon carcinoma cells in the lung after i.v. administration of tumor cells. Moreover, mice given B16 tumors and treated with anti-NK-1.1 had reduced survival. NK cells were important in host resistance to sublines of B16 that had been passaged either in vivo or in vitro, which express, respectively, high and low levels of class I major histocompatibility antigens. These findings support a role for NK cells in host defense against malignancy. The ability to selectively remove NK cells in vivo by MAb will permit a better understanding of their physiologic role.

Adenocarcinoma↗

PubMed1987

Measurement of tissue plasminogen activator in plasma. A comparison of 3 methods and description of a new improved technique.

Three methods for measurement of tissue plasminogen activator (t-PA) activity in plasma were compared with regard to linearity, precision and clinical applicability. Based on this comparison a new improved technique is described. The 3 methods differed in the way the influence of inhibitors in plasma was eliminated. In method A t-PA was measured in acidified plasma, in method B in euglobulin precipitate and in method C after adsorption of plasma on lysine-Sepharose. After addition of 15 IU/ml of t-PA to normal plasma the recovery with method A was 17.4 +/- 2.4 IU/ml, with method B 11.4 +/- 0.5 IU/ml and with method C 9.8 +/- 0.9 IU/ml. When tested on venous stasis plasma from 10 patients the 3 methods correlated well with a correlation coefficient of r = 0.97 - 0.99. Significantly higher values were found in acidified plasma (method A) as compared to the other methods. From this evaluation a method for determination of t-PA activity using acidification and internal standard to abolish the influence of inhibitors and poly-D-lysine as a stimulator was selected. The recovery with this method was 103.4 +/- 8.5% independent of PA inhibitor content in the plasma.

Acids↗

PubMed1987

Serotonergic influence on the growth hormone response to clonidine in rat.

Administration of the alpha 2-adrenoceptor agonist clonidine induces growth hormone (GH) release in rat and man. In the present study it is shown that the GH response to clonidine is weaker in rats exposed to depletion of both noradrenaline and serotonin (by means of reserpine or the combined treatment of FLA-63 and PCPA) than in animals exposed to noradrenaline depletion (by means of FLA-63) only. The possibility that an impaired serotonergic neurotransmission contributes to the blunted GH responses to clonidine observed in patients suffering from endogenous depression is discussed.

Animals↗

PubMed1987

Hand burns in children under 5 years of age.

In order to evaluate the epidemiology and functional results of hand burns in young children, 92 consecutive patients (126 hand burns) under age 5 years admitted to a Burn Center were reviewed. Scald burns (49 per cent) were most common, followed by flame (34 per cent), contact (14 per cent) and electrical burns (3 per cent). The child was left unattended by an adult in 53 per cent of cases and documented abuse was present in 6 per cent. The mean total body surface area (TBSA) burned was 17 per cent, and 77 patients (85 per cent) had additional burns in other areas (arms 34 per cent, legs 31 per cent, chest 29 per cent and face 27 per cent). Palmar burns occurred in 24 hands (19 per cent), dorsal in 41 (33 per cent), while both surfaces were burned in 61 (48 per cent). Joints involved included the MP in 96 (76 per cent), PIP in 87 (69 per cent) and DIP in 80 (63 per cent). The depth was superficial partial thickness in 53 (47 per cent), deep partial in 55 (44 per cent), and full thickness in 18 hands (14 per cent); a total of 29 hands were grafted (15 deep partial and 14 full thickness). Escharotomies were required in 12 hands (9 per cent) (9 flame and 3 scald) and partial amputation of digits was required in 3 (2 per cent). Follow-up was available in 46 hands from 7 to 120 months (mean 39 months). Partial thickness burns (34) healed with normal (32) or near-normal (2) hand function and developmental delay occurred in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Burn Units↗

PubMed1987

Inositol trisphosphate is generated by a rat natural killer cell tumor in response to target cells or to crosslinked monoclonal antibody OX-34: possible signaling role for the OX-34 determinant during activation by target cells.

RNK-16 cells, rat leukemia cells with features of natural killer (NK) cells, were adapted for growth in vitro and used to examine the mechanism of NK-cell activation. Contact of RNK-16 cells with tumor cells (YAC-1) that are lysed by NK cells, but not with resistant tumor cells (EL-4, K562), led to an increase in inositol trisphosphate (InsP3), a Ca2+-mobilizing messenger. A similar increase in InsP3 could be elicited in RNK-16 cells by monoclonal antibody OX-34, when the antibody was crosslinked by F(ab')2 fragments of goat antibodies to mouse immunoglobulin. This reaction was accompanied by an increase in the concentration of cytoplasmic free calcium Ca2+, due primarily to the release of Ca2+ from intracellular stores. In contrast to the stimulatory effects of crosslinked OX-34, OX-34 alone did not affect the levels of either InsP3 or cytoplasmic free Ca2+. Moreover, OX-34 alone blocked the generation of InsP3 by RNK-16 cells in response to YAC-1 cells and prevented target-cell killing. These findings demonstrate that OX-34 identifies a structure on the surface of RNK-16 cells that can stimulate the generation of InsP3, and they suggest that this structure can regulate signal transduction during target-cell recognition by NK cells.

Animals↗

PubMed1987

Reperfusion of skeletal muscle after warm ischemia.

The effect of 2 to 10 hours of tourniquet ischemia on the microcirculation of the tenuissimus muscle in 29 cats was studied by in vivo microscopy and electron microscopy. After release of the tourniquet there was immediate reperfusion and hyperemia in all muscles. Arterioles of 20 micron increased in diameter by 50% and venules of 35 micron by 30%. If the ischemia had lasted for 8 hours or more, reocclusion of flow occurred after 3 to 55 minutes. Platelet thromboembolism, sticking of leukocytes, and red cell aggregation seem to cause the occlusion.

Animals↗

PubMed1987

Glutaraldehyde-treated autogenous skin as a substitute for elastic cartilage: an experimental study.

In an experimental study in rats, a piece of dorsal skin was removed, molded, and tanned in glutaraldehyde. After rinsing in saline, the piece of skin was tested for extensibility and implanted under the dorsal skin of the same rat. It was removed after 1 to 12 weeks and its extensibility was again measured. Specimens were examined under the light and electron microscopes. None of the 63 implants extruded and at 12 weeks a thin, densely adherent fibrous capsule had formed. Light and electron microscopy revealed early inflammatory changes that later subsided. The implant maintained or increased its stiffness. The weight of the implant remained constant.

Animals↗

PubMed1987

Management of acute facial powder burns.

To evaluate the management and outcome of acute facial powder burns, 10 patients admitted to a burn center (1980-1985) were reviewed. Facial burns resulted from black gun-powder in 7 and fireworks in 3 patients. Most burns occurred in teenage boys (6) and all but 1 were the result of carelessness on the part of the burn victim. While most facial burns were treated conservatively, 2 patients sustained traumatic tattooing and underwent immediate debridement using a variety of surgical techniques in sequence. Good aesthetic results were obtained and the details of this approach are presented.

Adolescent↗

PubMed1987

Effect of arteriovenous flow reversal on blood flow and metabolism in a skin flap.

Twelve pig buttock island flaps (10 X 10 cm) were studied for 6 hours after arteriovenous flow reversal at the level of the pedicle. Follow-up was 48 hours. Blood pressure, Po2, pH, and lactate were measured in flap arteries and veins. Oxygen consumption was calculated. Data indicated true flow reversal. Blood pressure and Po2 in flap veins increased to systemic arterial levels. Outflow was provided by the arterial system, demonstrating venous pressure and Po2 values. Lactate increased significantly (1.8 +/- 0.5 to 4.0 +/- 2.3 mmol/liter), while pH dropped from 7.43 +/- 0.03 to 7.11 +/- 0.02. Oxygen consumption remained below baseline. In four flaps thrombosis occurred within 6 hours; no flap survived 48 hours. The results of this study do not encourage clinical application of the concept of flow reversal.

Animals↗

PubMed1987

Brain neurotransmission in panic disorder.

For two decades it has been hypothesized that schizophrenia and depression are related to alterations in the activity of specific neurotransmitters in brain; to a great extent, these theories are based on the assumed mode of action of antipsychotic and antidepressant drugs. With the available knowledge of how panic anxiety can be effectively treated (and elicited) with drugs, it is now reasonable to formulate hypotheses also regarding the contribution of central neurotransmitters to the generation of panic. As will be discussed in this brief review, three substances seem to be of particular importance in this context: serotonin, noradrenaline and GABA. In view of this concept, the putative mode of action of the atypical benzodiazepine derivative alprazolam, which in contrast to other benzodiazepines has been attributed effectiveness in the treatment of panic, will also be discussed.

Alprazolam↗

PubMed1987

Oestradiol increases baseline growth hormone levels in the male rat: possible direct action on the pituitary.

The effect of oestradiol treatment on the secretion of growth hormone (GH) was investigated in normal unrestrained male rats with chronic i.v. cannulae and in hypophysectomized male rats with autotransplanted pituitaries. The effect of gonadectomy of normal rats on the plasma GH secretory pattern was also evaluated. Baseline plasma GH levels were elevated following estradiol treatment of normal male rats (1.5 mg kg-1 per 15 days). Gonadectomy of male rats also resulted in increased baseline GH levels, although the effect was less apparent than after oestradiol administration. The pulse height was not influenced by gonadectomy or oestradiol administration. In male rats with the pituitary autotransplanted to the kidney capsule, oestradiol caused a dose-dependent increase in plasma GH levels, while there was no such effect of testosterone. These results suggest that the stimulatory influence of oestradiol on baseline GH levels is, at least partly, due to a direct effect on the pituitary. Plasma prolactin levels were elevated in rats with pituitary transplants receiving oestradiol. It is concluded that oestrogen administration to normal male rats increases baseline plasma GH levels, possibly by an effect exerted directly at the pituitary level.

Animals↗

PubMed1987

Changes in elemental composition of human muscle fibres following surgery and immobilization. An X-ray microanalytical study.

X-ray microanalysis of single muscle fibres visualized in the electron microscope has been applied to human muscle biopsies to quantify changes of intracellular elements after knee-surgery with subsequent immobilization for 6 weeks. An increase of intracellular chlorine (Cl; P less than 0.001) and of sodium (Na; P less than 0.1) concentrations were found 1 and 6 weeks post-surgery. Intracellular potassium (K), phosphorus and sulphur concentrations were not significantly changed. The increased Cl and Na concentrations may be an indication of a decreased activity of the ATPase-dependent Na/K-pump in the sarcolemma and/or of an increased sarcolemmal permeability for Na and Cl.

Adult↗

PubMed1987

A double blind trial of NSAID versus placebo during rehabilitation.

Forty patients participated in a randomized, parallel, double blind study of piroxicam, 20 mg daily, versus placebo, given orally for 10 days following open partial meniscectomy. On day 1, 3, 7, 11, and 21 after surgery the following parameters were studied: quadriceps torque measured isokinetically; patients' assessment of pain; active and passive range of motion measured with goniometer; degree of swelling and irritation of the operated knee; and efficacy of the medication. The mean values for all parameters, except for pain assessment, were in favor of the piroxicam group. This difference was most marked on day 7 and 11 and on these days highly significant. Our findings indicate that piroxicam may be able to improve early postoperative rehabilitation.

Adolescent↗

PubMed1987

Muscle fiber types in thoracic erector spinae muscles. Fiber types in idiopathic and other forms of scoliosis.

Histochemical studies of the thoracic part of the erector spinae muscles in scoliosis have shown a consistently higher proportion of Type 1 fibers on the convex side. The fiber distribution of the multifidus and semispinalis muscles was studied in adolescent idiopathic scoliosis (AIS). Compared with sex- and age-matched controls, a "normal" percentage of Type 1 fibers was found on the convex right side and significantly smaller percentage of Type 1 fibers on the concave side. Boys with AIS showed the same pattern as girls. In two patients with double major curves, the same pattern could be seen on the convexity of both curves. Patients with congenital scoliosis or scoliosis with early onset showed a different pattern with a "normal" percentage of Type 1 fibers on the concave side but a significantly greater percentage of Type 1 fibers on the convex side. In AIS, the deviation in the fiber distribution may constitute a primary factor in the pathogenesis of scoliosis. In congenital scoliosis the differences in fiber distribution between the convex and concave sides are considered secondary in the pathogenesis of the spinal curvature.

Adolescent↗

PubMed1986

Growth hormone responses to clonidine and GRF in spontaneously hypertensive rats: neuroendocrine evidence for an enhanced responsiveness of brain alpha 2-adrenoceptors in genetical hypertension.

Clonidine induces growth hormone (GH) release in rat. According to previous investigations this effect is mediated by postsynaptic alpha 2-adrenoceptors in the hypothalamus exerting a stimulatory influence on the recently discovered GH releasing factor (GRF). In the present study it is demonstrated that spontaneously hypertensive rats (SHR) of the Wistar-Kyoto strain display enhanced GH responses to clonidine as compared to normotensive Wistar-Kyoto control rats. In contrast, the GH responses to GRF are similar in hypertensive and normotensive animals. These findings indicate that brain alpha 2-adrenoceptors are more responsive in SHR than in normotensive controls. Since the enhanced GH responses to clonidine were observed also in young, prehypertensive SHR they are probably not secondary to the elevated blood pressure. The possible importance of an altered alpha 2-adrenergic neurotransmission for the development of elevated blood pressure in SHR is discussed.

Animals↗