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Biomedical subjects

D Danielsson

Publications and source records attributed to D Danielsson.

At least 109 records · Page 6Linked to original sources

Laboratory identification of pathogenic Neisseria with special regard to atypical strains: an evaluation of sugar degradation, immunofluorescence and co-agglutination tests.

Sugar degradation tests (SDT) were compared with immunofluorescence (IFL) and co-agglutination (COA) tests for the diagnosis of Neisseria gonorrhoeae (GC) and Neisseria meningitidis (MC). Somewhat more than 5% of the GC strains and 8% of the MC strains were misinterpreted by SDT. On most occasions the disagreement between SDT and serological tests was due to the inability of the MC strains (less so for GC strains) to degrade sugars correctly. Because of this, three out of 15 strains (20%) from pharyngeal specimens were primarily considered to be GC by SDT but were identified as MC by COA tests. Deficiencies in sugar degradations were also found in a group of clinical problem strains. Many of them were unable or had a decreased ability to degrade glucose or maltose but were diagnosed distinctly as MC by the COA test. There were no false positives with the IFL or COA tests, but 2% of the GC strains and 26% of the MC carrier strains (non-groupable) were not identified by COA. Both IFL and COA tests are good adjuncts to SDT for the diagnosis of GC and clinically significant MC, since the results are reliable and the tests rapid and simple to perform.

Agglutination Tests↗

Changes in the incidence of acute gonococcal and nongonococcal salpingitis. A five-year study from an urban area of central Sweden.

The incidence of acute gonococcal and nongonococcal salpingitis for a five-year-period (1970--74) was studied retrospectively in an urban area of central Sweden. The investigation was undertaken to see if the reported decrease of gonorrhoea in Sweden had been followed by a change in the incidence of gonococcal salpingitis--the most common complication of gonorrhoea. The study showed that the relative incidence of acute gonococcal salpingitis had decreased even more than urogenital gonorrhoea and these findings thus indicate a real decrease of gonorrhoea. At the same time there were more patients with nongonococcal salpingitis. During the period of the study the gonococcal complement-fixation test (GCFT) gave positive results in 40% to 80% of the patients with gonococcal salpingitis. The yield with this test was only 4% in patients with nongonococcal salpingitis during 1970 but it increased successively and was 23% in 1974. This increase was statistically highly significant (P less than 0.001).

Acute Disease↗

Induction of DNA synthesis in lymphocytes in vitro by various bacteria, with special reference to Neisseria gonorrhoeae, in patients with uro-arthritis (Reiter's disease).

Antigen-induced lymphocyte proliferation was studied by quantitation of 14C-thymidine uptake in cell cultures. The induction of DNA synthesis in vitro in lymphocytes from patients with uro-arthritis after stimulation by whole cells of virulent and avirulent N. gonorrhoeae, meningococci group B, and apathogenic Neisseria (N. pharyngis) was compared with the DNA synthesis in lymphocytes from healthy controls after stimulation with the same Neisseria antigens. The difference between patients and the controls was found to be highly significant after stimulation with virulent or avirulent N. gonorrhoeae organisms but not after stimulation with apathogenic Neisseria. An analysis of the correlation of the lymphocyte reactivity to all the Neisseria antigens showed a highly significant correlation between the response of uro-arthritis patients to the two types of gonococcal antigen (0.932*** and 0.859***), a lower correlation coefficient for group B meningococci and virulent or avirulent gonococci (0.724*** and 0.714***) and no correlation at all between apathogenic Neisseria and gonococci. The DNA synthesis in lymphocytes stimulated by N. gonorrhoeae and other Gram-positive and Gram-negative bacteria was also studied in cell cultures obtained from other healthy controls as well as uro-arthritis patients. There was no significant difference between the patients and the controls with regard to the response to apathogenic Neisseria and other non-Neisseria antigens.

Adult↗

Culture diagnosis of gonorrhoea--a comparison between two standard laboratory methods and a commercial gonococcal culture kit (Kvadricult).

The efficiency of a commercial kit--Kvadricult--intended for the culture diagnosis of gonorrhoea and specially designed to simplify "bedside" inoculation, was compared in two laboratories with their standard laboratory gonococcal (GC) culture methods. The yields of specimens inoculated "bedside" were compared with those inoculated after transport for 4-18 hrs in a modified Stuart transport medium. The highest positive yield was obtained by "bedside" inoculation with approximately equal results for the conventional methods and the Kvadricult system. Compared with "bedside" inoculation, the loss of positive specimens after transport was less than 10% in one laboratory but more than 17% in the other, which was found to be due to inferiority of the GC medium used in this laboratory, the reasons for which are discussed. Prolonged transportation of specimens for 2 days increased the loss of positive specimens, rising to as much as 55% even at the laboratory with the more efficient GC medium. These losses can obviously be avoided by transport for less than 24 hours--or better still, by "bedside" inoculation. From this point of view we have found the Kvadricult system efficient and easy to handle.

Bacteriological Techniques↗

Studies on the influence of antigens on the results with the gonococcal complement fixation test in patients with uncomplicated and complicated gonorrhoea.

The gonococcal complement fixation test (GCFT) was investigated with regard to its sensitivity and specificity by testing serum specimens from (a) female patients attending a VD out-patient clinic because of suspected gonorrhoea, (b) patients with a proven, uncomplicated, urogenital gonococcal, infection, (c) patients with disseminated gonococcal infection (DGI). Three different pools of gonococcal (GC) antigens were used which were comprised of GC strains from two different geographical areas. It was found that 39% of the females with culture-proven uncomplicated gonorrhoea had a positive GCFT whereas 10% of the females with negative GC cultures had a positive GCFT. The latter were found to have either a history of gonorrhoea or strong clinical suspicion of recent GC infection. One of the GC antigen pools gave a much lower diagnostic yield than the other two pools in the GCFTs with serum specimens from patients with uncomplicated gonorrhoea. However, no differences were found between the antigen pools in the tests with serum specimens from patients with DGI. These findings indicate the presence of various strain antigens participating in the immune response to complicated as well as uncomplicated GC infections. The results are presented in detail and discussed.

Antigens, Bacterial↗

Studies on Crohn's disease. 1. The relationship between Yersinia enterocolitica infection and terminal ileitis.

Patients with terminal ileitis or regional enterocolitis have been examined for signs of infection due to Yersinia enterocolitica serotype 3. The patients were grouped according to the length of preoperative history. Among 18 patients with preoperative symptoms of one week or less there were nine with positive signs of Yersinia enterocolitica infection. None of these patients developed the chronic form of Crohn's disease while two of the primarily Yersinia negative patients progressed to the chronic form. Among nine patients with preoperative symptoms of one week to three months there was one patient with positive signs of Yersinia enterocolitica infection. This patient has remained healthy whereas seven of the negative ones progressed to the chronic form of Crohn's disease. None of the patients with established Crohn's disease of the chronic form had signs of recent Yersinia infection. The findings indicate that patients with acute terminal ileitis and positive signs of Yersinia infection are not likely to progress to the chronic form of Crohn's disease. Bacteriologic and serologic investigation for Yersinia infection are therefore of prognostic value.

Acute Disease↗

Diagnosis of Neisseria infections by defined immunofluorescence. Methodologic aspects and applications.

Defined IF techniques have been used in our laboratories for the past 15 years for diagnosing meningococcal and gonococcal infections. Conjugates against these bacteria give desired specific staining (DSS) but also undersired specific staining (USS) due to cross-reacting antigens. USS is controlled by absorption. Nonspecific staining (NSS) of protein A-containing S. aureus caused by the reaction with the Fc part of the IgG molecule is blocked by adding RB 200-labeled antiS. aureus globulins to diluted FITC conjugates against gonococci or menigococci. Nss is also avoided by using FITC-labeled F(ab')2 fragments of IgG. By optimal labeling and separation of unlabeled FITC and heavily labeled molecules on Sephadex G-25 at low ionic strength and low pH, nonspecific reactions with tissues are reduced to a minimum. Defined IF can be utilized for diagnosing pathogenic Neisseria by examination of smears prepared from clinical specimens, as confirmative tests of oxidase-positive colonies, and for demonstrating these bacteria in tissue efflorescences and tissue biopsies. It is stressed that this technique should always be used in conjunction with conventional methods.

Absorption↗

Immune responses in eight patients infected with Bacteroides fragilis.

Sera from eight patients with either septicemia or pyothorax caused by Bacteroides fragilis were assayed for specific antibody by the agglutination, immunofluorescence, and agar gel diffusion techniques. Antibodies were detected in the sera of all eight patients by all three serological tests employed; titers as high as 1:160 and 1:320 were detected by the agglutination test and the immunofluorescence technique, respectively, and all patients had precipitating antibody. Failure of B. fragilis sub-species thetaiotaomicron to react with any heterologous antisera from the other seven patients infected with B. fragilis subspecies fragilis thetaiotaomicron was not serologically related to any of the other strains studied. Demonstration of an immune response to anaerobic infection supported the pathogenesis of anaerobes in infectious disease processes and indicated the possible diagnostic role that serological tests may serve in the diagnosis of anaerobic infections in humans.

Adult↗

The use of protein A-containing staphylococci sensitized with anti-meningococcal antibodies for grouping Neisseria meningitidis and demonstration of meningococcal antigen in cerebrospinal fluid.

The co-agglutination technique, utilizing antibody coated protein A-containing staphylococci, was successfully adapted to grouping N. meningitidis strains. It was found to give more clear-cut results than the standard slide test, especially in the case of strains isolated from throat specimens. The co-agglutination technique has also other advantages over the standard slide test in the grouping of meningococci: minor influence by auto-agglutination, higher specificity, easy performance and low consumption of specific antisera. Preliminary results also showed that the co-agglutination technique could be applied for the rapid detection of meningococcal antigen in cerebrospinal fluid.

Agglutination Tests↗

Circulating immune complexes in a patient with prolonged gonococcal septicemia.

A case of prolonged gonococcal speticemia is presented. Lack of genital symptoms, of demonstrable gonococcal antibodies in whole serum, and initially also of skin lesions contributed to a delayed diagnosis that was finally confirmed by positive blood culture. Evidence of circulating immune complexes was obtained by the demonstration of gonococcal IgG antibodies after dissociation of serum by gradient centrifugation of pH 4.0. The possibility that circulating immune complexes may contribute to the symptomatology of gonococcal septicemia is pointed out.

Adult↗

Slide agglutination method for the serological identification of Neisseria gonorrhoeae with anti-gonococcal antibodies adsorbed to protein A-containing staphylococci.

A rapid slide agglutination test has been developed for the identification of Neisseria gonorrhoeae that are primarily detected as oxidase-positive colonies in gonococcal cultures. The technique is based on the specific nonimmune reactivity between the Fc portion of immunoglobulin (Ig)G and staphylococcal protein A. IgG molecules adsorbed to stabilized staphylococci will thereby become oriented with their antigen-reactive sites that are directed outwards. Protein A-containing staphylococci with unabsorbed anti-gonococcal antibodies gave positive co-agglutination reactions with gonococci but also with meningococci, some Moraxella, Haemophilus, and Pseudomonas strains. These crossreactions were eliminated by absorption of the anti-gonococcal antiserum with meningococcal and Moraxella organisms prior to the coating of reagent staphylococci. In the routine culture diagnosis of N. gonorrhoeae the use of specific gonococcal reagent staphylococci gave concordant results with fermentation procedures and immunofluorescent techniques.

Adsorption↗