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Biomedical subjects

M Johansson

Publications and source records attributed to M Johansson.

At least 289 records · Page 16Linked to original sources

Isolation and characterization of two minor fractions of alpha 1-antitrypsin by high-performance liquid chromatographic chromatofocusing.

alpha 1-Antitrypsin is a glycoprotein that separates into five electrophoretic fractions, viz. M2, M4, M6, M7 and M8. Con A-Sepharose separates the protein into three fractions according to the branching degree of the three oligosaccharide chains. The Con A affinity is identical for M4 and M7 and for M6 and M8. Within each pair the proteins were isolated by rapid chromatofocusing. The M7 and M8 have the same carbohydrate structure as the major M4 and M6 respectively, but have lost the first five N-terminal amino acids (Glu-Asp-Pro-Glu-Gly) as compared to the majority of the protein.

Amino Acid Sequence↗

The role of negative charge in the complement-dependent dissociation of IgG-mediated aggregation.

The IgG-mediated aggregation of yeast particles was used as a model to study the dissociating effect of human serum complement on immune aggregates. A 92% decrease in non-aggregated particles was obtained by coating particles with IgG. After incubation of the aggregates in normal human serum (NHS) at 37 degrees C the number of free particles increased almost 10 times. The effect could be obtained with ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid-containing serum but not ethylenediaminetetraacetic acid-containing serum, indicating the importance of the alternate pathway of complement activation. Treatment with NHS did not release anti-yeast IgG from the particles, indicating that disruption of antigen-antibody bonds did not explain the phenomenon. The negative charge of the different particles was studied by measuring the interaction to diethylaminoethyl-Sephacel beads. Compared with non-coated and IgG-coated particles, the NHS-treated particles were not released until the ionic strength increased to 200 mM NaCl or the pH decreased to 4.4, indicating a strong negative charge of NHS-treated particles. We propose that complement increases the negative charge of immune complexes, thereby inducing repulsive forces that counteract Fc-Fc interactions and increase the solubility of the complexes.

Antibodies, Fungal↗

Complement activation according to the alternate pathway by glass and plastic surfaces and its role in neutrophil adhesion.

C3-deposition, generated by complement activation according to the alternate pathway, was detected on borosilicate glass slides and polystyrene Petri dishes. The C3-depositions grew peripherally until the entire surface was covered. The deposits were also visualized with scanning electron microscopy and could not be washed away with low-pH (3.5) or high-pH (9.6) buffers. No consumption of complement function was detected indicating a phenomenon restricted to the glass and plastic surfaces. The C3-deposits could mediate an adherence of human neutrophils.

Cell Adhesion↗

Intravenous computed tomographic cholangiography in acute cholecystitis. A comparison with conventional cholangiography.

Forty-nine patients with clinical signs of acute cholecystitis underwent conventional and computed tomographic cholangiography. Among 39 patients with signs of contrast medium in the biliary system at both examinations there was a diagnostic discrepancy in only one patient. Conventional radiography demonstrated cholecystopathy in this patient while contrast medium in the gallbladder and an acute pancreatitis were found at computed tomography. Ten patients with an indeterminate conventional cholangiography had a conclusive computed tomographic examination. Twenty of 30 patients with an abnormal computed tomographic cholangiography underwent cholecystectomy and all had diseased gallbladders. All 17 patients with histopathologically confirmed acute cholecystitis had signs of subserosal edema and/or changes in the omental fatty tissue adjacent to the gallbladder at computed tomography. A layer of tissue of water-density adjacent to the gallbladder and/or changes in omental fatty tissue were also seen in one patient with congestive heart failure and in one with a penetrating duodenal ulcer. None of the 19 patients with a normal computed tomographic cholangiography had a proven acute cholecystitis.

Acute Disease↗

Determination of noscapine in plasma by liquid chromatography.

A liquid chromatographic method has been developed for the determination of noscapine in plasma. Noscapine and the internal standard, papaverine, were extracted into methylene chloride by column extraction. The separation was performed on a straight-phase liquid chromatographic system using a mobile phase of hexane--methanol--chloroform--diethylamine. A high detection selectivity was obtained by UV detection at 310 nm. The precision of the method was 3.8% (standard deviation) at a level of 89 ng/ml and 9.5% (standard deviation) at 5.9 ng/ml. The selectivity of the analytical method was evaluated by comparing analytical results after isolation of extracts of plasma samples on reversed- and straight-phase liquid chromatographic systems.

Biotransformation↗

Cross-reactivity between enteric adenoviruses and adenovirus type 4: analysis of epitopes by solid-phase immune electron microscopy.

The immunological relationships between the two newly discovered serotypes of enteric adenoviruses, Ad40 and Ad41, and antisera to human adenoviruses representing all subgroups were studied by solid-phase immune electron microscopy. A pronounced two-way cross-reaction was seen between Ad40 (subgroup F) and Ad41 (subgroup G). Furthermore, a distinct one-way cross-reaction was noted between adenovirus type 4 antiserum (subgroup E) and virions of Ad40.

Adenoviridae↗

Two new serotypes of enteric adenovirus causing infantile diarrhoea.

Fastidious enteric adenovirus have recently been recognized as an important cause of acute gastroenteritis in young children. Their inability to grow in vitro has hampered classification by conventional methods. With modern immunological and chemical techniques the enteric adenoviruses have been shown to be distinct from the 39 established human adenovirus serotypes. In a prospective study of the viral, bacterial and parasitic aetiology of acute gastroenteritis 410 children and 205 age-matched controls were studied. An enteropathogenic agent was detected in 67% of the diarrhoeic patients and 57% were of viral origin. Rotavirus was the major agent found in 43% of the patients whereas adenovirus was found in 13%. Of the 50 adenovirus specimens, so far fully characterized by electron microscopy, ELISA-assays, DNA-restriction analysis and isolation studies 70% were identified as enteric adenoviruses. Two serotypes, adeno 40 and 41, were detected representing the new subgroups F and G. Twelve of 17 paired serum specimens, from children with enteric adenovirus showed a significant rise in hemagglutination inhibition titers. Infection with enteric adenoviruses showed 2 small seasonal peaks in summer and late winter. Infection occurred early in life, 85% of the children aged less than 3 years. Diarrhoea was the main symptom with an average duration of 9 days. Adenovirus type 41 seemed to cause diarrhoea of longer duration. Fever and vomiting was mild with a mean of 2 days. Respiratory symptoms occurred in 20% of the cases. The incubation period could be estimated as 7 days. Virus was excreted for 10-14 days.

Adenoviruses, Human↗

Pharmacokinetic properties of noscapine.

Noscapine was administered to five healthy volunteers in a randomized crossover design, as an intravenous infusion of 66 mg, and as an oral 150 mg dose of either rapidly dissolving tablets or a tablet containing ion exchange resin-bound noscapine. After i.v. administration, the disposition of noscapine was bi-exponential with an elimination half-life of 2.6 h; the total plasma clearance was 22 ml/min/kg and the volume of distribution (Vdarea) was 4.7 l/kg. The absolute oral bioavailability was 30%, with a 3.6-fold interindividual variation. There was no pharmacokinetic evidence to support a prolonged action of the ion exchange resin tablet.

Administration, Oral↗

Effects of surface-active alkyltrimethylammonium salts on concanavalin A-mediated agglutination in Acanthamoeba castellanii.

Pretreatment of Acanthamoeba castellanii (Neff strain) with sublytic concentrations of surface-active alkyltrimethylammonium salts (C12, C14, C16) enhanced ConA-mediated agglutination of the amoebae. Treatment with the surfactants alone did not affect the "spontaneous" agglutination of the amoebae. Electron microscopic (SEM and TEM) examinations of amoebae treated with sublytic concentrations of the surfactants did not reveal any significant alterations in cell shape or in cell surface morphology in treated cells. The binding of [3H]ConA to the amoebae was not affected by pretreatment with sublytic concentrations of the surfactants. It is suggested that the increase in ConA-mediated agglutination in surfactant-treated amoebae may be due to a fluidizing effect of the surfactants on plasma membrane of the amoebae. Part of the results of this work has previously been published in Eur. J. Cell Biol. 22, 210 (1980). (Abstract M 624).

Amoeba↗