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Biomedical subjects

H Johnsen

Publications and source records attributed to H Johnsen.

At least 19 recordsLinked to original sources

Lymph drainage and the development of post-reconstructive leg oedema is not influenced by the type of inguinal incision. A prospective randomised study in patients undergoing femoropopliteal bypass surgery.

OBJECTIVES: To see whether the type of groin incision influenced the degree of postoperative leg oedema and the occurrence of lymphatic damage. DESIGN: Prospective randomised clinical study. SETTING: University Department of Surgery. MATERIALS: Twenty-four patients undergoing femoropopliteal bypass reconstruction with either a lateral groin incision (Group A, n = 12) or a direct incision over the femoral vessels (Group B, (n = 12). CHIEF OUTCOME MEASURES: The leg volume increase was measured according to the formula of a truncated cone. Deep venous thrombosis was excluded by air plethysmography and colour-coded Duplex scanning. Lymphatic lesions were detected by lymphoscintigraphy using 99mTc labelled human serum albumin. MAIN RESULTS: One week following vascular reconstruction the median leg volume increase was 24.5% in Group A vs. 23.3% in Group B (NS). Lymphoscintigraphy revealed obstruction of the lymphatics in five patients of Group A vs. three patients of Group B (NS). Neither the occurrence of lymph cysts nor extravasation of lymph differed between the two groups. In seven patients no lymphatic lesion was observed. Patients with interruption of the lymphatics (n = 8) had a higher leg volume increase compared to the remaining patients with no or minor lymphatic lesions, 31.2% vs. 19.6%, respectively (p < 0.05). CONCLUSIONS: Leg oedema and the occurrence of lymphatic damage following femoropopliteal bypass surgery is not reduced by applying a lateral approach to the femoral artery in the groin. However, the higher leg volume increase in patients with lymphatic obstruction indicates that lymphatic damage could play a part in the leg oedema formation.

Aged

Cytokine levels in amniotic fluid and inflammatory changes in the placenta from normal deliveries at term.

Cytokine levels in amniotic fluid have been shown to increase towards term in normal pregnancies, and may play a regulatory role in parturition by stimulating the local production of prostaglandins. The work reported in the present paper was conducted in order to test the hypothesis that the increased cytokine levels may be induced by a subclinical inflammatory reaction in intrauterine tissues. The concentrations of tumor necrosis factor (TNF), interleukin 1 (IL-1), interleukin 2 (IL-2) and interleukin 6 (IL-6) were determined in samples of amniotic fluid from 38 women in delivery at term, after a clinically normal pregnancy. In 33 of the cases, tissue material was available for histological examination. In these, the extent of inflammatory cell infiltration was assessed in the fetal membranes, placenta and umbilical cord. A close interrelation was observed between the levels of the mediators typically released during inflammatory processes (TNF, IL-1, IL-6). Frank chorioamnionitis was not found in any of the histological specimens, although most placentae showed varying degrees of granulocyte infiltration in the fibrin layer under the chorion, sometimes also in the chorionic membrane. The degree of such leukocytic infiltration correlated positively with the levels of TNF, IL-1 and IL-6. These findings lend support to the hypothesis that a low-level inflammatory process may be a normal occurrence in the term placenta, and that this process may induce the production of cytokines, which, in turn, may play a role in the regulation of parturition. Such inflammation could be due to exposure of the fetal membranes to microbial material from the vagina, as the cervix dilates towards term.

Amniotic Fluid

Expression of the receptor for urokinase-type plasminogen activator in normal and neoplastic blood cells and hematopoietic tissue.

Expression of the receptor for the urokinase type plasminogen activator (uPAR) has been studied by flow cytometry and immunohistology in normal blood and bone marrow cells, in vitro activated lymphoid cells, and tissue samples from reactive lymph nodes (n = 6), thymus (n = 2) and malignant lymphomas (n = 82), or leukemias (n = 32). HL-60 myeloid precursor cells and CD34-positive normal stem cells also were analyzed. In the normal cells, staining was confined to monocytes, macrophages, neutrophils, and myeloid precursors. No labelling was seen of normal or activated lymphoid cells. Purified CD34-positive hematopoietic progenitors were uPAR negative, but expressed uPAR during differentiation in short-term liquid culture stimulated in vitro by recombinant interleukin (IL)-1, IL-3, IL-6, granulocyte-macrophage colony stimulating factor (CSF), granulocyte-CSF, and stem cell factor. Enhanced uPAR expression was also seen in HL-60 cells after induction of differentiation with dimethyl sulfoxide or 1 alpha,25-dihydroxyvitamin D3. In lymphomas and leukemias, the staining pattern was similar to that seen in the normal cells with labelling of monocytic and myeloid that seen in the normal cells with labelling of monocytic and myeloid malignancies, but not of the neoplastic cells in B-cell or T-cell lymphomas or Hodgkin's disease. In conclusion, uPAR is a differentiation marker for myeloid and monocytic cells, and may act to facilitate migration of these cells in normal and pathologic conditions by cell-associated plasminogen activation. Whether expression of uPAR in myeloid and monocytic malignancies relates to their growth and behavior will be an important topic for investigations in the future.

Blood Cells

Pressure increase following primary laser trabeculoplasty. Effect on the visual field.

Possible damaging effects on the visual field of postlaser pressure elevations the first 24 h following primary laser trabeculoplasty were investigated in 61 patients with exfoliative or open-angle glaucoma. The intraocular pressure was monitored the first 24 h after treatment. Treatment with pressure reducing agents was started if the intraocular pressure was > or = 50 mmHg. The visual field was plotted before and 1, 3, and 6 months after laser treatment with the C-30-2 program on a Humphrey visual field analyzer. Peak pressures > or = 50 mmHg occurred with 15 (25%) patients. There was no relationship between visual field changes at 1 month and pressure increase, peak pressure, prelaser pressure, prelaser visual field indices, the use of timolol postlaser, or the pressure decrease or pressure level 1 month after laser treatment. From 1 to 6 months after laser trabeculoplasty the visual field parameters remained stable. Postlaser pressure spikes do not seem to damage the visual field providing they are detected and treated.

Aged

Chlamydia trachomatis serovar L2 induces protein tyrosine phosphorylation during uptake by HeLa cells.

Chlamydia trachomatis L2 is an obligate intracellular microorganism with a unique biphasic life cycle. The extracellular form, the elementary body (EB), is infectious but metabolically inactive. Attachment of EBs to host cells is medicated by a heparan sulfate-like glycosaminoglycan. Following attachment, the EB is internalized within a membrane-bound vesicle, and during the first 8 h of infection the vesicles are transported to a perinuclear location where they aggregate and fuse. By use of a monoclonal antibody against phosphotyrosine, we showed that three classes of proteins are tyrosine phosphorylated: a triple band of 68, 66, and 64 kDa, a 97-kDa band, and a 140-kDa band. The phosphorylation could be detected by immunoblotting from 15 min after infection of HeLa cells. We followed the movement of the EBs and the tyrosine phosphorylation of proteins by double-labelling immunofluorescence microscopy with the same monoclonal anti-phosphotyrosine antibody and a polyclonal antibody against the C. trachomatis L2 outer membrane complex. During the first 8 h of infection, the phosphorylation colocalized with EBs. Sixteen hours after infection, EBs have reorganized to the replicating reticulate bodies, forming an inclusion. At this time, phosphorylation was seen as dotted spots in the periphery of the inclusion.

Actins

Methodological approach to the evaluation of neurotoxicity data and the classification of neurotoxic chemicals.

This text is the result of the authors' involvement in a working group on criteria for the identification and classification of neurotoxic chemicals. (The work of the group does not necessarily represent the official stand of the affiliated institutes.) A definition of neurotoxicity and criteria for evaluating studies dealing with neurotoxicology are presented. The evaluation is a stepwise process that ends with assigning the chemicals to groups depending on the available evidence for neurotoxicity (ie, neurotoxic, probably neurotoxic, possibly neurotoxic, probably not neurotoxic, or not classifiable). Finally, the description of the potency of neurotoxic chemicals is briefly discussed. The model has been tested by evaluating selected research papers on the following 10 chemicals: manganese, aluminum, tetrahydrofuran, cyclohexanone, dichlorvos, trichloroethylene, formaldehyde, tri-ortho-cresyl phosphate, n-hexane, and vinyl chloride. There was sufficient evidence for classifying five of the ten chemicals (aluminum, manganese, n-hexane, trichloroethylene, tri-ortho-cresyl phosphate) as definitely neurotoxic to humans, and three were considered to be possibly neurotoxic to humans (dichlorvos, tetrahydrofuran, vinyl chloride). Cyclohexanone and formaldehyde were not classifiable according to the model.

Animals

Intrapulmonary thrombin generation and its relation to monomethylmethacrylate plasma levels during hip arthroplasty.

Frequent peroperative sampling of arterial and mixed venous blood was undertaken in eight consecutive patients during cemented hip arthroplasty to obtain a sequential picture of thrombin-antithrombin (TAT) and methylmethacrylate monomer (MMA) concentrations. TAT, detected neo-antigenically, reached its maximum levels after bone preparation, prior to introduction of cement and prosthesis. Furthermore, TAT values were higher in arterial than in mixed venous blood, indicating generation and inactivation of thrombin when blood is passing the lung. MMA concentration, measured by high pressure liquid chromatography, increased very rapidly and declined within 1 min following socket as well as shaft implantation, reaching the highest mean value of 3599 ng/ml only 30 s after femoral impaction of cement. MMA concentration was higher in mixed venous than in arterial blood, indicating elimination of the monomer during lung passage. This study confirms our previous observation that coagulation is activated prior to the implantation of bone cement and prosthesis into the femoral shaft; in addition, it provides further evidence of the thrombin-generating potential of the pulmonary capillary bed. Very frequent sampling was necessary to reveal the sharp rise in MMA levels following impaction of cement. Further investigations are needed to establish whether interaction between activated coagulation and MMA may predispose to cardiovascular complications.

Aged

Carboxylesterases in guinea pig. A comparison of the different isoenzymes with regard to inhibition by organophosphorus compounds in vivo and in vitro.

The different isoenzymes of carboxylesterase (CarbE) from guinea pig liver, lung and plasma were separated by gel filtration and chromatofocusing. The isoenzymes were characterized by inhibition with several different organophosphorus compounds. The bimolecular rate constants showed the same tendency of decreased inhibition for all of the isoenzymes in the order; paraoxon greater than soman greater than diisopropylphosphofluoridate (DFP) greater than bis(p-nitrophenyl)phosphate. With two exceptions the inhibition constants for the different isoenzymes differed little. Subcutaneous and intraperitoneal administration of DFP and paraoxon rapidly inhibited the CarbE activity in guinea pig plasma. Much higher doses were necessary to obtain a marked inhibition in lung and liver. About 25% of CarbE activity in lung was resistant to paraoxon and DFP inhibition. Gel filtration of lung homogenate after treatment with the organophosphorus compounds showed that the CarbE activity of the medium molecular mass fractions was inhibited only weakly. This could be due to reduced accessibility to some of the lung CarbE isoenzymes.

Animals

Diurnal intraocular pressure after successful primary laser trabeculoplasty.

In 20 patients who were successfully treated with laser trabeculoplasty as the primary therapy for glaucoma, we measured the intraocular pressure every two hours between 8:00 A.M. and 8:00 P.M. Success was defined as intraocular pressure of 22 mm Hg or less without medication. Of 20 patients, three had open-angle glaucoma and 17 had exfoliative glaucoma. Intraocular pressure was stable with small fluctuations during the daytime.

Aged

Pilocarpine to prevent acute pressure increase following primary laser trabeculoplasty.

The effect of pilocarpine pretreatment on the transient pressure elevations immediately following primary laser trabeculoplasty was investigated in a prospective, randomised study. Fifty eyes of 50 patients, 33 with exfoliative and 17 with simple glaucoma, were treated in 360 degrees of the trabecular meshwork. The mean maximum pressure increase was 2.4 (SD = 4.4)mm Hg with pilocarpine pretreatment and 12.8 (SD = 11.2)mm Hg without pretreatment (p less than 0.05). Except in two cases, all peak pressures appeared during the first two hours after treatment. The degree of chamber angle pigmentation was predictive of the magnitude of the post laser hypertensive pressure response in eyes without pretreatment (p less than 0.05).

Aged

Long-term efficacy of primary laser trabeculoplasty.

Sixty glaucomatous eyes of 60 patients treated with laser trabeculoplasty as primary therapy were reviewed retrospectively. There were 42 eyes with capsular glaucoma and 18 with simple glaucoma. The mean prelaser intraocular pressure (IOP) was 35.2 (SD = 6.5) mmHg. Success was defined as IOP less than or equal to 22 mmHg without medication. The probability of success was 0.73 at 1 year, 0.66 at 2 years, 0.57 at 3 years, and 0.50 at 4 years. Three eyes experienced progressive visual field loss or disc damage in spite of an intraocular pressure below 22 mmHg without medication. High prelaser pressure and the severity of the visual field defects were significant predictors of treatment failure.

Aged

[Orbital blow-out fractures. Therapeutic results].

37 patients treated surgically for orbital blow-out fractures were reviewed retrospectively. 29 had diplopia before and four after operation. The diplopia was present only in extreme gaze positions and was not troublesome to the patients. Enophthalmus was present in 19 patients preoperatively and in six postoperatively. Of six patients treated conservatively one developed a moderate enophthalmus. There were no significant postoperative complications.

Adolescent

The immediate pressure response to primary laser trabeculoplasty--a comparison of one- and two-stage treatment.

The immediate pressure response to primary LTP was studied prospectively in 40 eyes randomised to one- and two-stage treatment in 360 degrees of the trabecular meshwork. There were 26 eyes with glaucoma capsulare and 14 with glaucoma simplex. Mean prelaser IOP was 32.8 mmHg in the former, and 35.5 mmHg in the latter group. The frequency and magnitude of postlaser pressure increase were the same in both groups when taking into consideration the pressure spikes in both 180 degrees sessions. The pressure increase was higher than in earlier reports on LTP in presurgical glaucoma patients on maximum medication. Almost all IOP elevations appeared during the first 2 h following laser treatment. The results were the same in both groups 6 months after LTP.

Aged

Metabolism of T-2 toxin by blood cell carboxylesterases.

Human and rat blood hydrolysed T-2 toxin along two different pathways giving HT-2 toxin and neosolaniol as primary metabolites, respectively. Neosolaniol represents a metabolic pathway different from that obtained by liver. Rat erythrocytes formed neosolaniol as a primary metabolite whereas white blood cells hydrolysed T-2 toxin to HT-2 toxin. Human erythrocytes formed both HT-2 toxin and neosolaniol whereas all human white cells produced only HT-2 as the primary metabolite. The enzymes responsible for hydrolysis of T-2 toxin to HT-2 toxin in white blood cells and T-2 toxin to neosolaniol in red blood cells were all identified as carboxylesterases by use of specific inhibitors. The ratio between trichothecene hydrolysis and 4-nitrophenyl butyrate hydrolysis varied among the different cell fractions indicating that specific isoenzymes are involved.

Animals

Cytotoxicity and effects of T2-toxin on plasma proteins involved in coagulation, fibrinolysis and kallikrein-kinin system.

The activity of both the coagulation and fibrinolytic systems was markedly depressed 24 h after a sublethal dose of T-2 toxin. T-2 toxin was active as an anticoagulant at low doses, which did not affect the basal state of the animals. The kallikrein-kinin system was also affected by depletion of the prekallikrein, which indicates increased bradykinin levels in plasma. At the same time there was an increased activity of some clinically relevant enzymes in serum, indicating tissue injuries caused by T-2 toxin. All effects observed in this study reached their maximum within 24 h after administration, which corresponds to the time animals usually die when receiving a lethal dose. T-2 toxin does not, however, seem to affect the protease enzymes by reduced protein synthesis, because of early onset of the effects, nor does it act as a trigger itself. The effect of T-2 toxin on plasma protease enzymes is probably secondary to cytotoxic effects in the vascular endothelium.

Animals