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Biomedical subjects

M E Johansson

Publications and source records attributed to M E Johansson.

At least 19 recordsLinked to original sources
PubMed1992

Restriction endonuclease patterns of adenovirus type 12 and 18.

Restriction endonuclease analysis using 10 restriction enzymes was performed on six and three wild isolates of adenovirus (Ad) type 12 and 18, respectively. Among the Ad12 strains, five DNA variants could be identified. The degree of pairwise comigration of restriction fragments suggests a high degree of genomic diversity within Ad12. The wild isolates of Ad18, on the other hand, displayed a low degree of genetic variability and comprised one DNA variant closely related to the prototype strain. The BglII, BstEII, and HindIII restriction endonuclease patterns of Ad18 were inconsistent with those originally presented. Identical RE-patterns among Ad18 prototype strains (DC) obtained from four different sources, including directly from the American Type Culture Collection, verify that the genuine Ad18 prototype was used in the present study. Using the revised restriction patterns of BglII, BstEII, and HindIII, a proper identification of Ad18 will be facilitated.

Adenovirus Infections, Human↗
PubMed1992

Intrauterine fetal death due to echovirus 11.

In a case of intrauterine fetal death in the 29th week of gestation, echovirus 11 could be isolated from the umbilical cord of the fetus. The mother had no apparent signs of infection but serological evidence of current echovirus 11 infection. Enterovirus PCR performed on paraffin-embedded specimens of various tissues (myocardium, lung, liver and placenta) from the fetus yielded positive results in all cases. These findings, together with supporting serological and epidemiological findings--e.g. proven echovirus 11 infection 3 weeks before in the 18-month-old son of the woman--constituted strong evidence that echovirus 11 infection was responsible for the fetal death.

Adult↗
PubMed1991

Genome analysis of adenovirus type 31 strains from immunocompromised and immunocompetent patients.

Adenovirus type 31 (Ad31) was isolated from 15 immunocompromised patients in 12 of whom seroconversion was also recorded. Ad31 infection has a substantial clinical relevance since 8 of 10 with lower respiratory tract infection and 4 of 4 with hepatitis died. Therefore, Ad31 isolates from immunocompetent and immunodeficient hosts were compared by restriction endonuclease analysis. Nine genome types were identified among the 79 Ad31 isolates. Pairwise comparison of comigrating restriction fragments indicated that the genome types could be divided into three genomic clusters. Several Ad31 genome types were isolated from immunocompromised patients, but no highly virulent genome type could be found. A genome type was identified in a child with severe combined immunodeficiency who originally was infected with another genome type. This observation is suggested to have evolutionary implications.

Adenovirus Infections, Human↗
PubMed1989

Characterization of two genome types of adenovirus type 31 isolated in Stockholm during 1987.

The authors isolated during 1987 seven adenovirus type 31 (Ad31) within a 9-month period. The isolates were obtained from urine, throat, and feces, implying a systemic spread of the infection. Most patients displayed gastrointestinal symptoms, but some had respiratory symptoms and fever. All of the strains differed by restriction endonuclease analysis from the prototype strain (1315) by an additional Bgl II restriction site. Ad31 isolates 1-6 could be divided into two groups by the enzymes Bam HI, Msp I, and Xho I. Each enzyme gave rise to the same group distribution: isolates 1-3 and 4-6, respectively. Digestion with Bst EII, Hind III, Kpn I, and Sma I resulted in identical patterns for isolates 1-6. Isolate 7, however, demonstrated a DNA deletion of approximately 0.8 kbp, but it was otherwise identical to isolates 4-6. In conclusion, two separate genome types of Ad31 were isolated, one of which included a DNA deletion mutant. The increased isolation rate may reflect an epidemiological situation, as the same isolation procedure had been used both before and after this period.

Adenovirus Infections, Human↗
PubMed1986

Investigation of the film formation of magnesium stearate by applying a flow-through dissolution technique.

The film formation of magnesium stearate on the surface of acetylsalicylic acid was investigated by applying a flow-through dissolution technique. The effect of mixing time, lubricant surface area, and the addition of colloidal silica was studied. The film formation increased by increasing mixing time. The final level reached was independent of the specific surface area of the lubricants, but granular magnesium stearate gave a lower surface coverage than the powdered lubricants. The lubricating effect was independent of the mixing time and specific surface area of the lubricants. Colloidal silica was found to interact primarily with the free fraction of magnesium stearate.

Aspirin↗
PubMed1985

Enzyme-linked immunosorbent assay for detection of enteric adenovirus 41.

An enzyme-linked immunosorbent assay (ELISA) for direct detection of enteric adenovirus 41 (Ad41) in stool specimens was developed and compared with an Ad40-specific ELISA described previously [Johansson et al, 1980]. Rabbit antiserum to Ad41 was obtained by immunization with purified virions. To eliminate genus-specific reactivity the serum was passed through an immunosorbent column containing soluble adenovirus components of members of subgenera A to E. The anti-Ad41 serum still displayed high reactivity against Ad40 and had to be immunoabsorbed with soluble virus components of Ad40 to be rendered type-specific. The absorbed antiserum was used in an indirect ELISA and proved to be specific for Ad41. No heterotypic reactivity against Ad40 or Ad1 through Ad35 was found. The Ad41-specific ELISA proved to be of equal sensitivity to electron microscopy. The type-specific ELISAs for Ad40 and Ad41 were evaluated by testing 76 stool specimens containing enteric adenoviruses originating from England and Scandinavia. All specimens could be typed--41 (54%) as Ad40 and 35 (46%) as Ad41. These results were confirmed by DNA restriction site analysis. The type-specific ELISA proved to be a specific, sensitive, and a rapid technique for detection of Ad41 and allowed clear-cut discrimination from Ad40 in clinical specimens.

Adenoviruses, Human↗
PubMed1985

Preformulation studies in a drug development program for tablet formulations.

Recently developed techniques were applied in a preformulation program to select a compound and a suitable salt for use in a one-month toxicological test. The program showed that valuable information can be obtained prior to the choice of a compound as a candidate for a solid-dosage form. Information about the physical and mechanical properties of the chosen compound can be obtained with a limited amount of substance, i.e., surface color and hygroscopicity (1-2 g), dissolution rate and solubility (1-2 g), powder properties (1-2 g), and compaction properties (5-7 g).

Chemical Phenomena↗
PubMed1985

Influence of the granulation technique and starting material properties on the lubricating effect of granular magnesium stearate.

Magnesium stearate has been granulated in four ways to produce lubricant granulations with different properties. The lubricating properties, as well as the tablet properties with the granulated lubricant, were evaluated on tablets prepared from a mixture of dicalcium phosphate, corn starch and microcrystalline cellulose. The lubricating effect of the magnesium stearate granulations showed a similar pattern regardless of the granulation technique used except for a granulation with providone. Increasing the particle size of the magnesium stearate granulation increased the amount of lubricant required to obtain lubrication similar to powdered magnesium stearate. Variations in the specific surface area of the starting materials could be masked by using them in granular form.

Chemistry, Pharmaceutical↗
PubMed1984

Importance of enteric adenoviruses 40 and 41 in acute gastroenteritis in infants and young children.

In a prospective 1-year study of acute infantile gastroenteritis, adenoviruses were detected in the stools or by seroconversions, or both, in 56 of 416 (13.5%) ill children. By use of DNA restriction enzyme analysis, enzyme immunoassay, and culture techniques, 33 of 56 (59%) adenovirus specimens were identified as enteric adenoviruses 40 and 41 (Ad40 and Ad41). They were found as the sole recognizable cause of diarrhea in 30 of 416 (7.2%) ill children and in 0 of 200 controls. Three additional ill children had enteric adenoviruses as a part of a dual infection. Evidence for established adenoviruses (Ad1 through Ad39) in gastroenteritis was found in 15 of 416 (3.6%) ill children but also in 3 of 200 (1.5%) controls. Eight adenovirus specimens remained untyped. Seroconversions were demonstrated in 17 of 18 (94%) paired serum samples from patients shedding enteric adenoviruses. The predominant symptom of infections with enteric adenoviruses was diarrhea, with a mean duration of 8.6 days (Ad40) and 12.2 days (Ad41). One-third of the children with Ad41 infections had prolonged symptoms (greater than or equal to 14 days). The frequency of respiratory symptoms was low (21%). The established adenoviruses presented a different clinical picture, characterized by diarrhea of shorter duration, higher fever, and significantly increased occurrence of respiratory symptoms (79%). In conclusion, enteric adenoviruses appear to be an important cause of acute infantile gastroenteritis, second only to rotaviruses in this study.

Acute Disease↗
PubMed1979

Identification of an enteric adenovirus by immunoelectroosmophoresis (IEOP) technique.

Infantile gastroenteritis can be caused by several of the established adenovirus types. There are also adenoviruses that defy in vitro cultivation but have been recognized by electron microscopy. One isolate of these viruses, which have been designated enteric adenoviruses, has been characterized. Several of the established adenovirus types are shed in stools over long periods. The conditions for direct identification of enteric adenoviruses by immunoelectroosmophoresis (IEOP) have therefore been evaluated. Application of this technique requires highly specific reagents. However, a high prevalence of antibodies in rabbits reacting with human rotavirus was noted. For these reasons, immunoadsorbent purified antibodies were prepared. Because of the difficulty in purifying immunogens from stools, an immunization procedure characterized by immunization with adenovirus subunits bound to affinity chromatography beads was elaborated. An identification procedure for adenoviruses causing infantile gastroenteritis based a) on IEOP using group-specific and monospecific antibodies and b) on the determination of the in vitro cultivatability is suggested.

Adenoviridae Infections↗
PubMed1979

Preparation of specific antisera against adenoviruses by affinity bead immunization (ABI).

Certain adenovirus types can be replicated only to low titer in tissue cultures. Other, such as adenovirus strains associated with infantile gastroenteritis, cannot be replicated in vitro. A method which allows preparation of specific antisera has therefore been evaluated. The procedure involves coupling of group-specific antibodies against adenovirus capsid subunits to CNBr-activated Sepharose 4B; reaction of crude virus suspensions with immobilized adenovirus-specific IgG; elimination of contaminating material by extensive washing using a wide pH range; and immunization with adenovirus immunogens immobilized on the beads. Efficient immunization was obtained with immunogen doses of both 50 ng and 50 microgram. The immunization procedure which has been designated affinity bead immunization (ABI) could therefore have a wide applicability in cases where the relevant immunogen constitutes a minor fraction of a crude preparation.

Adenoviruses, Human↗
PubMed1979

Preparation of sera for subtyping of influenza A viruses by immunofluorescence.

The conditions for preparation of type-specific and subtype-specific influenza A virus reagents to be used in the immunofluorescence technique have been evaluated. Type A-specific antibodies were prepared by passing an antivirion hyperimmune serum through an immunoadsorbent column containing antigens from disrupted virions of a different influenza A virus subtype. The type-specific antibodies were recovered from the immunoadsorbent by desorption with 3 M NaI. For subtype determination, antisera against the various hemagglutinins were used. Such sera could be prepared by removal of irrelevant influenza A virus antibodies from sera directed against purified virions and isolated peplomers, respectively. This was performed by passing the antisera through immunoadsorbent columns containing antigens from disrupted virions of appropriate strains. However, attempts to obtain a hemagglutin-specific antiserum from a serum directed against allantoic fluid virus suspension failed with this procedure. Antisera obtained after immunization with purified hemagglutinin were also elaborated. These sera were shown to be superior for subtyping of influenza A virus infections by immunofluorescence, but could not a priori be regarded as subtype-specific. The usefulness of subtype-specific sera has been demonstrated on clinical specimens for rapid virus diagnosis.

Animals↗
PubMed1978

Elimination of inter-species reactive anti-IgG antibodies by affinity chromatography.

Inter-species reactive anti-IgG antibodies are disturbing in blocking and interference experiments with the sensitive mixed hemadsorption (MH) technique. By affinity chromatography this disturbance could be efficiently eliminated. Anti-IgG sera were passed through columns containing heterologous IgG. The absorption technique is rapid and simple. After one absorption the inter-species reactivity in anti-IgG sera had been decreased thousand-fold, while any loss of species-specific reactivity could not be detected. Such absorbed anti-IgG sera reacted only with homologous antibodies. The effect is exemplified with e.g. blocking of human HLA antibodies by anti-beta2-microglobulin from rabbits.

Animals↗
PubMed1978

Preparation of sera for typing of adenovirus infections by immunofluorescence.

The conditions for preparation of adenovirus antisera with group, subgroup and type-specific reactivity to be used in the immunofluorescence technique have been evaluated. Group-specific antibodies were prepared by passing an antiserum against virions or hexons of one serotype through an immunosorbent column containing soluble viral components of an adenovirus type belonging to a different subgroup. The group-specific antibodies were recovered from the solid phase by elution at pH 2.8. Reagents specific for subgroup I and II were obtained by passing anti-dodecon sera through an immunosorbent column containing soluble viral components from heterologous subgroups. In this case antibodies not attaching to the absorbent were recovered. Sera against fibers of subgroup III members could be used as subgroupspecific sera without absorption. Type-specific antibodies were prepared by removal of antibodies of other specificities by passing anti-virion or anti-hexon sera through immunosorbent columns containing soluble viral components of an adenovirus type belonging to the same subgroup. Reagents specific for seven adenovirus types representing Rosen's three subgroups were prepared according to the outlined procedures.

Adenoviridae Infections↗
PubMed1976

Antibodies to calf serum as a cause of unwanted reaction in immunofluorescence tests.

One potentially important cause of disturbing staining of cell cultures used for immunofluorescence (IF) tests was found to be a specific reaction between calf serum and corresponding antibodies. A simple method utilizing polymerized calf serum as an immunosorbent was used for the removal of the antibodies causing the undesired reactions. One to three cycles of absorption with the calf serum immunosorbent were highly efficient in removing antibodies to calf serum, whereas the titer of a heterologous antiserum (anti-egg albumin) was only slightly affected by the same procedure. An enzyme linked immunosorbent assay (ELISA) was used for determination of the efficacy of the absorption method.

Absorption↗