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Biomedical subjects

P R Hansen

Publications and source records attributed to P R Hansen.

17 recordsLinked to original sources
PubMed1992

Effect of 5-aminosalicylic acid on myocardial capillary permeability following ischaemia and reperfusion.

OBJECTIVE: The aim was to evaluate the effect of 5-aminosalicylic acid on myocardial capillary permeability for small hydrophilic molecules after ischaemia and reperfusion. METHODS: Open chest anaesthetised dogs were subjected to a 20 min occlusion of the left anterior descending coronary artery followed by 1 h reperfusion. 5-Aminosalicylic acid (bolus injection 12 mg.kg-1, followed by 105 micrograms.kg-1.min-1) (n = 10) or saline (control, n = 12) was given intravenously for 1 h, starting 20 min before ischaemia. The myocardial plasma flow rate, myocardial capillary extraction fraction, and myocardial capillary permeability-surface area (PS) product for 99mTc-DTPA were determined before ischaemia, and 5 and 60 min after the start of reperfusion by employing the single injection residue detection method. Immediately after reperfusion, the reactive hyperaemic plasma flow was measured by the 133Xe washout method. RESULTS: Four dogs (two untreated and two treated with 5-aminosalicylic acid) were eliminated due to ventricular fibrillation at the time of reperfusion. In the remaining animals (10 controls and eight treated) the plasma flow rate, capillary extraction fraction and PS were similar before myocardial ischaemia. After 5 min reperfusion, the plasma flow rate and PS were significantly increased in control animals (p < 0.02 and p < 0.008, respectively), but were unchanged in dogs treated with 5-aminosalicylic acid. In addition, after 5 min reperfusion, PS was significantly higher in the control group than in treated animals (p < 0.005). Microcirculatory variables returned to preocclusive values in both groups by 60 min after reperfusion. 5-Aminosalicylic acid had no significant effect on haemodynamics or on reactive hyperaemic plasma flow. CONCLUSIONS: The results suggest that 5-aminosalicylic acid can attenuate the microvascular changes after reversible myocardial ischaemia. The effect is potentially beneficial, and may be mediated by well recognised anti-inflammatory actions of 5-aminosalicylic acid (ie, scavenging of oxygen free radicals and neutrophil inhibition).

Aminosalicylic Acids↗
PubMed1991

[Reversible regional myocardial ischemia in variant angina].

A case of severe ventricular ischaemia induced by hyperventilation which occurred in a woman aged 44 years is presented. The ischaemia was confirmed by echocardiography and scintigraphy and coronary arteriography revealed spasm in the proximal segment of the anterior descending branch of the left coronary artery.

Adult↗
PubMed1991

[Antiphospholipid antibodies and ischemic heart disease].

A case is presented with severe ischemic heart disease and lupus anticoagulant in a 24 year old otherwise healthy male. Anticoagulation was initiated and coronary by-pass grafting was performed. Coronary biopsy showed no signs of arteritis.

Adult↗
PubMed1991

[Amyotrophic lateral sclerosis: an autoimmune disease?].

Amyotrophic lateral sclerosis is characterized by degeneration of the motor neurones in the central nervous system and, as a rule, the condition results in rapid incapacity and death. The etiology is unknown but experimental results from recent years suggest that immunological mechanisms are of pathophysiological significance. Gangliosides constitute an important membrane component in nerve tissue and the majority of patients probably have high titres of circulation polyclonal IgM-antibodies to these compounds, particularly gangliosides GM1 and GD1a. The antibody titre appears to be correlated with the clinical condition and selective immune suppression (e.g. with cyclophosphamide) may possibly be of therapeutic value.

Amyotrophic Lateral Sclerosis↗
PubMed1990

Detection of CMV DNA and CMV antigen in renal allograft biopsies by in situ hybridisation and immunohistochemistry.

One hundred kidney allograft biopsies from 85 patients and tissue specimens from 31 failed allografts were analysed by immunohistochemistry (IMH) with a monoclonal antibody against a cytomegalovirus (CMV) antigen and by in situ hybridisation (ISH) with a biotinylated CMV DNA probe. Six clinically and serologically CMV-infected patients with AIDS served as positive controls. Biopsies from six seronegative donor kidneys and autopsy specimens from five clinically and serologically negative patients served as negative controls. Adequate serology in 56 patients showed 50% to be actively CMV infected. No statistically significant difference was found between the frequency of acute rejection in the seropositive and the seronegative patients. Four seropositive transplanted patients contained CMV DNA or CMV antigen in the biopsies and in the grafts. Both methods gave a negative result in 15 patients with glomerulopathy. Expression of MHC class I and II antigens in 17 of the biopsies demonstrated no relation to positive serology or local demonstration of CMV. In conclusion, (1) CMV was not renotropic, (2) there was no correlation between (a) CMV and acute rejection, (b) CMV and glomerulopathy, or (c) CMV and MHC class I and II antigen expression. The study suggests that CMV does not play a major role in rejection.

Antigens, Viral↗
PubMed1989

[Autoimmune neuropathy].

Chronic progressive polyneuropathy is frequently cryptogenic but occurs in association with monoclonal gammopathy. In cases of this type, a relatively mild, mainly axonal sensomotor neuropathy is frequently present and may be difficult to distinguish from carcinomatous neuropathy in malignant conditions without the presence of the M-component. In benign essential gammopathy (MGUS) with an M-component of IgM-kappa class, the neuropathy is frequently demyelinizing and the paraprotein reacts specifically with carbohydrate determinants in myelin-associated glycoprotein (MAG) and other glycoproteins and glycolipids in peripheral nerve tissue. Demonstration is undertaken by immune fluorescence investigation (eg on skin biopsy material) whereas serological diagnosis involves difficulties. There is much evidence to suggest that the autoimmune reaction is of significance for the development of nerve damage and uncontrolled trials have shown beneficial effects of immune suppression including plasmapherisis. The latter treatment should be considered in the Guillain-Barré syndrome, neuropathy and HIV-infection and also in motor neurone disease and IgM-MGUS, in which autoimmunological mechanisms may also be of pathophysiological significance.

Autoantibodies↗
PubMed1976

Aggregation of acridine orange: crystal structure of acridine orange tetrachlorozincate 2C17H19N3-2HCl-ZnCl2-CH3COOH.

The crystal structure of the biological stain, "acridine orange," has been determined. This compound, when crystallized from ethanol, is shown to be a zinc chloride double salt of acridine orange, containing, in addition, acetic acid of crystallization. These additional components are residuals from the method of preparation of acridine orange. This complex, 2 acridine orange-2HCl-ZnCl2-CH3COOH, (2C17H19N3-2HCl-ZnCl2-CH3COOH) crystallizes in the monoclinic space group P21, a = 9.965 (2), b = 21.507 (6), c = 9.645 (2) A, beta = 113.98 degrees (2), V = 1888.7 (8) A3, FW = 800.0, Z = 2, DX = 1.41 g-cm-3, Dobs = 1.43 (9) g-cm-3. Three-dimensional diffraction data were collected with CuKalpha radiation, and the structure refined to R = 0.065 for 1885 observed reflections. In the crystal structure hydrogen bonds are formed, via the protonated nitrogen atom of the central rings of two acridine orange cations, to two chloride ions in a ZnCl42- tetrahedral grouping. These two acridine orange molecules are stacked in parallel planes, approximately 3.4 A apart, with the long axes of the ring systems inclined at 26.5 to each other. Thus an apparent dimerization of the acridine, orange is facilitated by the anions present, resulting in the complex studied. The two -N(CH3)2 groups of each acridine orange molecule are not protonated in this crystalline form. The mode of molecular packing found here may be relevant to models for the external stacking of acridine orange around a DNA molecule. The importance of removing any zinc salt from acridine orange preparations prior to aggregation studies is stressed.

Acridines↗