[Spondylodiscitis without fever: a diagnostic challenge]. / Spondylodiszitis ohne Fieber: Eine diagnostische Herausforderung.

HISTORY AND CLINICAL FINDINGS: Three patients with different forms of vertebral osteomyelitis are presented, two with hematogenous infections caused by Streptococcus pneumoniae and Staphylococcus aureus and one with postsurgical infection after excision of a vertebral disc caused by coagulase-negative staphylococci. None of the patients was initially febrile, but all had localized back pain and a restricted range of movement of the vertebral column. EXAMINATIONS, DIAGNOSIS: In all three patients the MRI of the affected vertebral column was consistent with vertebral osteomyelitis. Microbiological diagnosis was made by bone biopsy in all patients and by blood cultures in two of them. TREATMENT AND COURSE: Antibiotics were administered for 4-6 weeks. At follow-up two patients were without symptoms, but the third patient had persistent back pain without radiological signs of vertebral osteomyelitis. CONCLUSION: In patients with localized back pain vertebral osteomyelitis should be included in the differential diagnosis, even if there is no fever and no increase in white cell count, the erythrocyte sedimentation rate or C-reactive protein level and radiography is normal. Specific bacterial diagnosis should be made by multiple bone biopsy or blood cultures, before starting appropriate antibiotics.

The role of folate, antioxidant vitamins and other constituents in fruit and vegetables in the prevention of cardiovascular disease: the epidemiological evidence.

Evidence that fruit and vegetables may protect against coronary heart disease is accumulating. It is unclear which constituents of fruit and vegetables are responsible for this protective effect. Folate as a co-substrate in homocysteine metabolism may be important. An intake of about 400 micrograms folate equivalents/day seems to be required to achieve stable low homocysteine blood levels. Five of eight epidemiologic studies show significant inverse associations between folate and cardiovascular disease. These associations could be confounded by antioxidant vitamins and/or other substances. In trials examining an association between folate and cardiovascular disease such confounding must be excluded, before specific recommendations can be given. Observational studies suggest that vitamin C plays a role in the aetiology of cardiovascular disease, but there are no completed intervention trials of this vitamin alone. With regard to vitamin E two cohort studies point to cardiovascular benefits with the long-term use of supplements of at least 100 IU/day, but the results of controlled trials are inconclusive. There is some evidence from observational studies of an inverse association between beta-carotene and cardiovascular disease, particularly in smokers. Intervention trials do not support this hypothesis, rather, they suggest a possible harmful effect of beta-carotene supplements in smokers. Nevertheless, protective effects of beta-carotene and vitamin E in different dosages, durations of administration, or different combinations are still possible. The last paragraph of this review discusses limitations of the present and priorities of future research.

Folate and the risk of colorectal, breast and cervix cancer: the epidemiological evidence.

It is only recently that folate deficiency has been implicated in the development of cancer. The mechanisms by which folate might protect against cancer are not clear but may relate to its role in DNA methylation and DNA synthesis. All case-control, cohort and intervention trials reported in English, French, or German, on folate intake or blood levels in relation to the risk of colorectal, breast, and cervix cancer were reviewed. Twenty case-control, and 12 nested case-control or cohort studies were identified. The epidemiological studies consistently show an inverse association between intake and/or levels of folate and the frequency of colorectal carcinomas, and less clearly of adenomas. Long-term use of supplements of folate seems to be of greater benefit than dietary intake. The effect of folate seems to be modulated by alcohol, methionine, and MTHFR polymorphisms. Results from animal studies suggest that folate supplementation might decrease or increase cancer risk depending on dosage and timing. Recent studies also suggest an inverse association between folate intake and breast cancer among women who regularly consume alcohol. Conversely, epidemiological evidence remains uncertain for the role of folate in cervical cancer prevention; the results of two intervention trials on rates of cervical intraepithelial neoplasia regression or progression were negative. An effect of folate later in carcinogenesis is not supported by the few (nested) case-control studies on invasive cervical cancer. Some of the conflicting results may be due to the fact that dietary intake or blood levels of folate do not accurately reflect folate concentrations in the cells of cancer origin. Furthermore, only a few studies have taken into account the modulating effect of alcohol, methionine, and MTHFR polymorphisms in their analyses. The observed inverse associations between folate and risk of cancer, on the other hand, may be confounded by various factors, especially by other potentially protective constituents in fruits and vegetables. Ongoing intervention studies can strengthen evidence for causality by excluding such confounding, but the optimal dose, duration, and stage of carcinogenesis and the appropriate (genetically predisposed) study group for folate chemoprevention are not yet defined.

Genotoxicity of ethyl carbamate (urethane) in Salmonella, yeast and human lymphoblastoid cells.

Ethyl carbamate is a known carcinogen occurring in fermented food and beverages and is therefore of interest for food safety assurance. We studied the genotoxicity of ethyl carbamate in Salmonella typhimurium, in Saccharomyces cerevisiae and in human lymphoblastoid TK6 cells. In absence of cytochrome P450 enzymes, no ethyl carbamate-mediated genotoxicity was observed in any of the three test systems in the non-cytotoxic range. In the presence of an activating system, ethyl carbamate was found to be mutagenic in Salmonella typhimurium strain TA100 but not in strains TA98 and TA102, indicating base-pair substitutions at G-C base pairs. In contrast, no significant mutagenicity of ethyl carbamate could be detected in human lymphoblastoid TK6 cells. However, applied in cytotoxic concentrations, ethyl carbamate was genotoxic for Saccharomyces cerevisiae in the absence of P450-mediated metabolic activation. Inhibitors of P450IIE1 (DMSO, ethanol and dithiodiethylcarbamate) diminished ethyl carbamate-mediated mutagenicity in Salmonella typhimurium strain TA100 in a dose dependent manner, suggesting that P450IIE1 is the activating enzyme.

[Folic acid in the prevention of neural tube defects]. / Folsäure zur Verhütung von Neuralrohrdefekten.

Neural tube defects (spina bifida) imply a severe limitation of quality of life. 70 to 100% of these defects are preventable by additional intake of folic acid during the periconceptional period. In accordance with the recommendations of Anglo-Saxon and other authorities prevention of this grave malformation should be attempted not only after a first-affected child, but primarily in a general manner in Switzerland, too. All women of childbearing age not under contraceptives should be advised to consume a diet rich in folic acid and to take an additional daily dose of 0.4 mg folic acid as a monosubstance or with a multivitamin preparation. A supplement of folic acid to cereal grain products, mainly bread flours, is recommended. A generally elevated folic acid intake may have further beneficial effects, such as risk reduction for the occurrence of carcinoma and atherosclerosis.

Polymerase chain reaction (PCR): a possible alternative to immunochemical methods assuring safety and quality of food. Detection of wheat contamination in non-wheat food products.

A rapid, sensitive and specific analysis of food samples determining wheat contamination was established using polymerase chain reaction (PCR) technology. First, primers specific for highly conserved eukaryote DNA sequences were used to prove isolated nucleic acid substrate accessibility to PCR amplification. Subsequently, a highly repetitive and specific genomic wheat DNA segment was amplified by PCR for wheat detection. This assay was tested with 35 different food samples ranging from bakery additives to heated and processed food samples. In addition, the PCR method was compared to an immunochemical assay that detected the wheat protein component gliadin. Combination of both assays allowed a detailed characterization of wheat contamination. Hence, wheat flour contamination could be distinguished from gliadin used as a carrier for spices as well as from wheat starch addition.

Structure/activity relationships of the genotoxic potencies of sixteen pyrrolizidine alkaloids assayed for the induction of somatic mutation and recombination in wing cells of Drosophila melanogaster.

Sixteen pyrrolizidine alkaloids (PAs) were examined for their genotoxic potency in the wing spot test of Drosophila melanogaster following oral application. This in vivo assay tests for the induction of somatic mutation and mitotic recombination in cells of the developing wing primordia. All PAs tested except the C9-monoester supinine were clearly genotoxic. Depending on their chemical structure, however, genotoxicity of the PAs varied widely in a range encompassing about three orders of magnitude. In general, macrocyclic diester-type PAs were the most and 7-hydroxy C9-monoester types the least genotoxic representatives studied, while open diesters were intermediate in this respect. Stereoisomeric PAs mostly showed similar, but sometimes also clearly unequal genotoxicity. An increasing number of hydroxy groups in the PA molecule seemed to reduce its genotoxic potency. With respect to the structure/activity relationships, there appears to be a good correlation between hepatotoxicity of PAs in experimental rodents and genotoxicity in the wing spot test of Drosophila. This suggests that PAs are bioactivated along similar pathways in the mammalian liver and in the somatic cells of Drosophila. The genotoxic potential of PAs in the Drosophila wing spot test and their carcinogenic potential in mammals also seem correlated, although the information in the literature on carcinogenicity of the non-macrocyclic PAs with moderate to low genotoxic potency is concededly limited. Comparisons with other genotoxicity tests suggest that the wing spot test is particularly suitable for genotoxins like PAs, on the one hand because of the versatile metabolic bioactivation system of Drosophila and on the other hand also because of its excellent sensitivity to the crosslinking agents among the genotoxins.

Toxicity and mutagenicity of anthraquinones from Aspergillus chevalieri.

More than 100 strains of the Aspergillus glaucus group were cultivated on synthetic media for 11 days at 28 degrees C. Organic extracts of fungal material were screened by thin-layer chromatography (TLC) for the mycotoxins aflatoxins B1,2 and G1,2, sterigmatocystin, ochratoxin A, gliotoxin, patulin, and xanthocillin X. None of these toxins were produced in detectable amounts under experimental conditions. Nevertheless, organic extracts exhibited high toxicity after intraperitoneal (i.p.) administration in mice. Aspergillus chevalieri strain ZT 8268 was selected for further investigation of its toxic metabolites. The main toxic action was attributed to the four anthraquinone derivatives, physicion, physcionanthrone B, physciondianthrone, and erythroglaucin, which were isolated and identified. No toxic effects were found after oral administration. Using the Salmonella/mammalian microsome test, mutagenic activity (frame-shift) was detected in strain TA 1537 in the presence of S-9 liver microsome preparation.

Goitrin--a nitrosatable constitutent of plant foodstuffs.

N-nitrosamides are known as direct-acting carcinogens at the site of their formation; they do not need any metabolic activation in vivo. The conditions leading to their formation in the stomach, and also their genotoxicity, have been thoroughly studied with some model compounds. Several reports link this type of compound to the induction of gastric cancer in human. However, only limited data are presently available about possible precursors of N-nitrosamides in foods. In the present study we found that goitrin --a naturally occurring compound in cruciferous vegetables and rape--could be easily nitrosated by treatment with nitrite under stomach conditions, yielding with loss of sulfur the N-nitroso- oxazolidone 4 (fig.). This product has a mutagenicity pattern and potency similar to that of N-nitroso-N-methyl-N'- nitroguanidine (MNNG) in the Ames Salmonella/mammalian microsome test.

In vivo covalent binding of aflatoxin B1 and aflatoxin M1 to liver DNA of rat, mouse and pig.

[14C]Aflatoxin B1 (AFB1) was isolated from cultures of Aspergillus parasiticus grown on [1-14C]sodium acetate. Covalent binding of AFB1 to liver DNA of rat and mouse was determined 6-8 h after oral administration. The effectiveness of covalent binding, expressed as DNA binding per dose in the units of a 'Covalent Binding Index' (CBI), (micromol aflatoxin/mol DNA nucleotides)/(mmol aflatoxin/kg animal), was found to be 10 400 for rats and 240 for mice. These CBI partly explain the different susceptibility of the two species for the incidence of hepatic tumors. The corresponding values for pig liver DNA, 24 and 48 h after oral administration, were found to be as high as 19 100 and 13 300. DNA-binding has not so far been reported for this species although it could represent an appropriate animal model for studies where a human-like gastrointestinal tract physiology is desirable. Aflatoxin M1 (AFM1) is a metabolite found in the milk of cows that have been fed AFB1-contaminated diet. [14C]AFM1 was also found to be produced by cultures of A. parasiticus giving a yield of about 0.3% of the total aflatoxins. A test for covalent binding to rat liver DNA revealed a CBI of 2100 showing that AFM1 must also be regarded as a strong hepatocarcinogen. It is concluded that AFB1 contaminations should be avoided in dairy feed.

Stereology of liver biopsies from healthy volunteers.

The stereological model and the base-line data of normal human liver needle biopsy-specimens are presented. Four reference systems were introduced: 1 cm3 of liver tissue, 1 cm3 of hepatocyte, 1 cm3 of hepatocytic cytoplasm and the volume of an average "mononuclear" hepatocyte. The sampling was done at three levels of magnification (1,000 X, 5,000 X and 10,000 X). A lobular differentiation was not considered. The baseline data show strikingly small variations (s.e. less than 10%) within the individual biopsy specimen and within the group of four biopsies. There is no principal difference between human beings presented here, rats, mice and dogs. Only the mean individual volume of human hepatocytes is clearly larger than in rodents. The problems and limitations of stereological work on liver biopsy specimens are discussed.