NIPH annals最新文献

Dietary questions were directed to patients and controls in a follow-up study of incident meningococcal disease cases in Norway, winter 1981-1982. The questions emphasized the main iron sources in the usual diet. The daily intake of iron from some sources was estimated, and the various groups compared. The differences were small.

Paired sera from 10 patients and a convalescence sample from one patient suffering from campylobacteriosis were analysed for IgG, IgM and IgA antibodies against the infective organism (Campylobacter jejuni PEN 0:6,7) with a DIG-ELISA system. Either formalinized, ethanol-inactivated or heat-inactivated preparations of the infecting organism were used as antigens. Cross reactivity was tested with human sera having agglutinating antibodies against Yersinia enterocolitica (N = 6) or Salmonella typhi or S. parathyphi b (N = 7). All patients displayed IgA and IgM levels in the convalescence sample above that found in healthy blood donors (N = 55). Using the ethanol-inactivated or formalinized preparations more than 90% of the convalenscence sera showed IgG levels above that found in blood donors whereas the heat-inactivated preparation detected 73% IgG positives in the same group of sera. Serum from one patient infected with S. parathyphi b was positive in the test. This finding was interpreted as most likely due to a double infection. The study suggests that serum IgA may be a valuable marker for infection with this microorganism. Both the formalinized and the ethanol-inactivated preparations showed presence of flagella in contrast to the heat-inactivated preparation.

The results of C-reactive protein (CRP) measurements in 176 patients hospitalized with suspected systemic meningococcal disease (MCd) are presented. 115 patients had meningococcal disease and 61 patients had other diseases and served as control patients. On admission to hospital high CRP levels were found in patients with meningococcal disease, markedly above the levels found in patients with viral infections. The CRP level fell to nearly normal level during the first week of treatment. CRP on admission to hospital had no prognostic value. Pretreatment CRP level can be valuable in the differential diagnosis between meningococcal disease and other diseases.

Antibody production was investigated for ten patients from a group of 20 who had contracted infections with a strain of Campylobacter jejuni of serotype PEN 6,7. Production of antibody was determined by titrating ten sets of paired sera for agglutination of formalin-treated and heat-treated cell suspensions and by passive hemagglutination using both sheep and human O Rh-red blood cells sensitized with extracted soluble thermostable antigens. All patients had demonstrable antibodies against the formalin-treated cells, six had a four-fold or greater increase in antibody levels. Nine patients showed antibodies against the heat-inactivated cells of whom five showed a fourfold or greater rise in antibody levels. Three patients developed antibodies against the extracted thermostable antigens. Sera from 100 blood donors served as controls. Six paired sera from patients that had antibodies against the heated suspension were analyzed by an immunofluorescence technique for determining IgM, IgA and IgG antibodies against live and heat-inactivated bacteria. Each of the six sera displayed antibody response primarily of the IgM and IgA class with highest levels against live cell suspensions.

During 1985 four external quality assessment tests for clinical microbiology were performed, each consisting of four simulated clinical specimens. The results are reported, evaluated and some problem areas discussed.

Sera from fifty couples were assayed for the presence of antibody to Cytomegalovirus. In twenty of the couples only one partner was seropositive. If serological status accurately distinguishes between infected and uninfected individuals, these data indicate that conjugal transmission of Cytomegalovirus is inefficient.

Serum specimens for external quality assessment in virology were sent as an open distribution to 10-13 clinical microbiological laboratories during the period 1982-84. Antibodies to rubella were tested by hemagglutination-inhibition (HI); other viral antibodies were tested by complement fixation (CF). The median of the antibody-titres for each annual batch of serum specimens is used to describe and evaluate the laboratory performance. Generally speaking the antibody titres in both tests were found to cover a wide range.

Primary monolayer cultures of hepatocytes are very useful for both in vitro screening of cytotoxic and genotoxic chemicals and for studies on mechanisms of action of such compounds. However, culturing hepatocytes as monolayers result changes in the activity of drug metabolizing enzymes, with a reduction of cytochrome P-450 dependent enzyme activities as the most important examples of such changes. Thus, the overall metabolism of toxic chemicals in hepatocyte cultures seem to be closest to the in vivo situation in the earlier time periods after isolation. Compared to suspension cultures, monolayer cultures makes it possible to follow toxic effects of a chemical over a longer period of time. However, hepatocytes do not readily replicate in culture, making studies on gene or chromosomal mutational effects impossible. Despite these limitations, several studies have shown that monolayers of hepatocytes represent a good experimental model for studies on many aspects of the genotoxic effects of chemical carcinogens, such as the formation of covalently bound adducts to DNA, DNA breakage and DNA repair synthesis. The use of inhibitors of various drug metabolizing enzymes, have illustrated that different cellular effects of a carcinogen may be caused by different metabolites. Many aspects of modification of the carcinogenic process, such as the effects of co-carcinogens, anti-carcinogens and inducers of xenobiotic metabolism, as well as strain and species variations in metabolism, have been widely studied in hepatocyte cultures. Hepatocyte cultures have also been successfully used as a metabolic activation system in co-cultures with other cells which will respond to cytotoxic, mutagenic and/or carcinogenic metabolites. The use of monolayers of hepatocytes as metabolic activation system seems often to be more relevance to in vivo situation compared to the use of subcellular fractions in such studies. When extrapolating data from such in vitro studies to the in vivo situation it should be borne in mind, however, that cancer development may relate more to the proportion of the dose which is activated and less on the rate of activation. Furthermore, cancer development is a complex, multistage process which obviously is not only dependent on the genotoxic and cytotoxic characteristics of a chemical.

Use of a magnetic evaluation table with a resolution of 0.1 mm connected to a built-in microprocessor and a marking stylo, combined with a previously developed computer system, allows a rapid and precise measurement of the inhibitory zones of growth around antibiotic-containing discs.

The developmental hazard of six chemicals was tested in vitro in the Hydra attenuata assay which is based upon the differential toxicity between the adults and a regenerating stage known as an artificial "embryo". The toxicity of DMSO, ethyl alcohol, lindane and paracetamol was similar for both adults and embryos. On the other hand, sodium valproate and isoniazid was, respectively, seven and 100 times more toxic for embryos than adults, thus indicating that these pharmaceuticals might pose developmental hazards to mammalian development. The differential toxicities seen in the Hydra assay reflect analogous data on laboratory animals.