Cerebral phosphate metabolism in first-degree relatives of patients with schizophrenia.

OBJECTIVE: Most phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) studies have described measures of lower membrane anabolism or greater catabolism in the frontal lobes of patients with schizophrenia. The purpose of the present study was to evaluate whether these findings can also be detected in young subjects at genetic risk for schizophrenia. METHOD: Fourteen children and siblings of patients with schizophrenia (mean age=16.7 years) and 14 comparison subjects (mean age=16.9 years) were included in a (31)P-MRS study of the frontal lobe. RESULTS: The high-risk subjects had significantly lower mean ratios of phosphomonoesters to phosphodiesters (0.25 versus 0.31) and higher mean phosphodiester values (37.59% versus 34.87%) than comparison subjects. CONCLUSIONS: These findings suggest greater phospholipid breakdown even in young first-degree relatives of patients with schizophrenia. This suggestion is discussed with respect to the membrane phospholipid hypothesis of schizophrenia.

Serotyping of 80 strains from the WHO multicentre international typing study of Listeria monocytogenes.

Serotyping was carried out on 80 coded strains, distribute to all laboratories taking part in the WHO L. monocytogenes multicenter subtyping study. All six laboratories used the method recommended by their coordinator. All 80 strains were typeable. There was complete agreement between the six laboratories on 49 (61.3%) strains (21 serovar 1/2a and 28 serovar 4b strains) which in turn were identical to the expected serovars, known only after decoding. The intralaboratory reproducibility carried out on 11 duplicate strains, ranged from 82 to 100%, with a medium value of 91%. Reproducibility of serotyping L. monocytogenes strains according to serovar varied from 33.3 to 100% for serotypes 3b and 1/2a, respectively, with serovar 4b (x) being incorrectly identified in all six laboratories. Serotyping of L. monocytogenes is easy and simple and is a useful prerequisite for other finer and more discriminatory typing methods. Problems may however, be encountered mainly with the flagellar antigenic factors. There is a need, therefore, for preparing antisera of good quality from which efficient antigenic factors can be obtained.

Listeria in effluents from the food-processing industry.

There is general agreement that listeriosis has a significant impact on Man as well as on animals. Listeria monocytogenes has been isolated from the faeces of healthy human and animal carriers and from various environmental sources. L. monocytogenes is the pathogenic species most responsible for abortion, septicaemia and meningitis in animals and Man. Listeria ivanovii is a primary cause of abortion in animals. Owing to a number of epidemics and single cases caused by food contaminated with L. monocytogenes, listeriosis has received more attention in the past ten years than ever before. Entry of the organism into food-processing plants is primarily caused by animals which excrete Listeria in their faeces. Other sources of entry are raw foods of animal origin and personnel in food establishment. Proliferation of Listeria is promoted by high humidity and nutrient waste in certain food production plants. Removal of Listeria is almost impossible by routine disinfection. Listeria-contaminated sites pose a serious risk of recontamination of food-processing equipment and processed foods. Moreover, such sites represent an inexhaustible source of entry for Listeria in plant effluents. There is no denying that effluents from food-processing plants increase the spread of Listeria in the environment. However, considering the existence of other sources of entry, such as human and animal husbandry wastes, and that circulation and recontamination within the environment itself are also possible, this may not be a particularly important risk.

First isolation and characterisation of Borrelia garinii, agent of Lyme borreliosis, from Irish ticks.

Nymphal Ixodes ricinus, the tick vector of Lyme borreliosis, were collected from the edges of paths in Muckross Demesne, Killarney National Park, Co. Kerry, Ireland. Examination of some of these nymphs by indirect immunofluorescence showed an infection prevalence of 12% with Borrelia burgdorferi sensu lato, the spirochaete agent of Lyme borreliosis. Gerbils (Meriones unguiculatus) were infected by infesting them with other nymphs from the same batch. Subsequently uninfected laboratory larvae were applied to the gerbils and the contents of the resulting infected engorged ticks were then placed in media and the spirochaetes cultured. The spirochaetes were identified as B. burgdorferi sensu lato by indirect immunofluorescence using monoclonal antibodies and they were further characterised by polymerase chain reaction and pulsed-field gel electrophoresis. Both of these latter techniques showed that spirochaetes in all samples belonged to the genomic species, Borrelia garinii.

[Screening for carriers of cystic fibrosis mutations in Ashkenazi volunteers].

309 DNA samples obtained from healthy volunteers were tested for the cystic fibrosis mutations DF508 and W1282X. 14 carriers were identified, 7 of each mutation. Since the 2 mutations account for only 80% of CF mutations, the actual number of carriers is 1 in 18. In spite of the fact that this is only a pilot study, the results suggest that screening for CF carriers is feasible and that it identifies unambiguously those who carry the CF genes. When testing for CF carriers becomes available for the general public, it will undoubtedly contribute in reducing significantly the incidence of children born with the disease.

[Serodiagnosis of Lyme borreliosis: development and evaluation of a test system for epidemiological studies in the dog]. / Serodiagnostik der Lyme Borreliose: Entwicklung und Bewertung eines Testsystems für epidemiologische Untersuchungen beim Hund.

The aim of the study was to develop and validate a serological test system for extended epidemiological investigations to which extend dogs were exposed to Borrelia burgdorferi. For this purpose, 121 samples of dogs which were suspect of an infection and submitted to the laboratory for serological testing, were investigated in an immunofluorescence test (IFT) and to different enzyme-linked immunosorbent assays (ELISA). Valuation of the ELISA systems was assessed in relation to the IFT. Sensitivity, specificity and predictive values were calculated for negative, positive and also borderline values. In the screening test all samples with a positive titre in IFT were judged positive. Samples negative in IFT showed negative results in the screening in only 86%. All samples positive in screening or of borderline value in IFT were again tested using a confirmatory ELISA. By this procedure a specificity of 100% and a sensitivity of 85% was calculated for samples with positive or negative IFT titres, respectively. Samples with IFT borderline titres (1:64 or 1:128) were judged negative in this ELISA in 80% and borderline in 16%. Checking of selected samples in an immunodot test confirmed the ELISA results. Sera being negative in ELISA showed also no specific reaction in this test. When considering the possibility of false positive reactions in IFT, rather high percentages of sensitivity and specificity could be found. Because all real positive samples could be detected using the confirmatory ELISA as a single test, there is no further need in epidemiological investigations to use the screening test. For specific problems the Western blot can be used.(ABSTRACT TRUNCATED AT 250 WORDS)

["If Berger had survived the second world war - he certainly would have been a candidate for the Nobel Prize". Hans Berger and the legend of the Nobel Prize]. / "Hätte Berger das Ende des zweiten Weltkrieges noch erlebt -- gewiss wäre er ein Anwärter auf den Nobelpreis geworden" -- Ein Beitrag zum 200. Jahrestag der Gründung der Jenaer Psychiatrischen Klinik.

The public opinion pays much attention to the Nobel Prize as an indicator for the scientific efficiency of a university or a country in connection with foundation of so-called elite universities. The former holder of the psychiatric chair in Jena and discoverer of the electroencephalogram Hans Berger (1873 - 1941) came into discussion as candidate for the Nobel Prize in physiology or medicine. The current medical-historical publications maintain the view that Berger should have received the Nobel Prize in 1936 as well as in 1949. This was prevented in 1936 by an enactment from Hitler, which forbid him to accept the prize, and later in 1949 by Berger's own death. According to documents of the Nobel archives these statements can be disproved. Berger was only nominated three times out of 65 nominations in 1940. Because of his death the other two recommendations in 1942 and 1947 were never evaluated.

Antibodies against Leptospira biflexa serotypes patoc and são paulo in pigs: possible occurrence and importance for the intracutaneous test for leptospirosis.

Leptospirin for the diagnosis of leptospirosis by an intracutaneous test contains antigenic material from 5 pathogenic Leptospira serotypes (10). During experiments with rabbits and pigs, leptospirin was injected into 6 pigs which had been infected artificially with apathogenic Leptospira biflexa serotypes patoc and são paulo. Three out of the 6 pigs showed a positive leptospirin reaction (11). This interfering reaction in animals having been infected with apathogenic L. biflexa was the reason to investigate the occurrence of biflexa antibodies in pigs from different areas in Germany by the microscopic agglutination. None of the 854 pigs showed biflexa antibodies producing a 50% agglutination at a serum dilution of 1:100. If at all, pigs may become infected naturally by L. biflexa; this apparently seems to be a rare incident. An impairment of the diagnostic value of leptospirin by L. biflexa antibodies can be excluded.

Studies on the effect of antibiotic substances on leptospires and their cultivation from material with a high bacterial count.

Leptospira species are difficult to isolate from sperm specimens because rapid growth of the contaminant flora will kill the pathogen. The resistance of 5 Leptospira strains to 5 different antibiotics was examined with a view to an inhibition of such contaminant growth. Neomycin (10, 20, 30 mg/l), vancomycin (5, 8, 10 mg/l), nalidixic acid (50, 75, 100 mg/l), streptomycin (5, 8, 10 mg/l) and chloramphenicol (5, 10, 20 mg/l) were added separately to Korthof's culture medium containing rabbit serum. The comparative growth rates of the leptospires were evaluated. Against the control medium, all 5 antibiotics were found to have an adverse influence on the multiplication phase. In conformity with literature data, vancomycin (10 mg/l) and nalidixic acid (50 mg/l) were found to have the lowest effect. In the cases of streptomycin and chloramphenicol, there was a high reduction of the leptospiral count and even a complete lack of multiplication. A combination of vancomycin (10 mg2l) and nalidixic acid (50 mg/l) was used for the recovery of leptospires from porcine sperm. To inhibit a growth of Ps. aeruginosa, 5000 U/l polymyxin B were added. The strongly inhibitory action of polymyxin B on leptospiral growth could be eliminated by subculturing in a medium free from inhibitory substances after 2 days.

Growth of 10 Leptospira interrogans serovars using polyvinylpyrrolidone(PVP)-treated Tween in protein-free medium.

Polyvinylpyrrolidone (PVP)-treated Tween was used to prepare a protein-free medium for cultivation of leptospires. 6 out of 25 media were selected for culturing 10 serovars of leptospires. The best results were achieved in a medium containing Tween treated with PVP 25000. In several subcultures 8 out of 10 serovars reached a concentration of 10(8) leptospires/ml or more, when cultured in tubes without aeration.l Only in the case of 2 serovars (Leptospira interrogans serovars grippotyphosa and tarassovi) growth was not satisfactory. The results have shown that it is possible to detoxify Tween with the aid of polyvinylpyrrolidone. In the meantime the 40th subculture of 8 strains has been prepared.

[Serologic studies of the occurrence of Borrelia burgdorferi in domestic animals in Berlin (West)]. / Serologische Untersuchungen zum Vorkommen von Borrelia burgdorferi bei Haustieren in Berlin (West).

The prevalence of B. burgdorferi, the causative agent of Lyme Borreliosis in humans, was determined in domestic animals living in Berlin. 189 dogs, 29 cats, 224 horses and 194 cows were investigated. Using the indirect immunofluorescence test (IFT) 5.8% of the dogs and 24.5% of the cows investigated showed a positive reaction at titres of 1:128 or higher. Horses and cats gave negative results. ELISA was more sensitive than IFT. 10.1% of the dogs, 16.1% of the horses and 66% of the local cows showed positive reaction. Domestic animals seem to be in contact with B. burgdorferi and can be a reservoir for the spirochete. Also there is the possibility that domestic animals get clinically ill.

[The isolation and differentiation of leptospires from cattle drinking water]. / Beitrag zur Isolierung und Differenzierung von Leptospiren aus Viehtränken.

The cultural isolation and identification of leptospires from three water samples of farm wells were described. All three strains isolated belong to the apathogenic species L. biflexa. The cattle stock of these farms (A, B, C) had reacted serologically to serovars hardjo and grippotyphosa. The strain isolated from farm A is a new serovar called krefeldi and belongs to serogroup Doberdo. The strain isolated from farm B belongs to serovar montefiascone of serogroup Botanica and the strain from farm C to serovar bessemans of serogroup Bessemans. It is remarkable that serovar krefeldi with all the sera of farm A (titre up to 1:40) and only with part of the sera of farm B reacted.

[Borrelia burgdorferi, clinical aspects, cultivation and identification of the pathogen in erythema migrans in Berlin]. / Borrelia burgdorferi, klinische Aspekte, Anzüchtung und Identifizierung des Erregers aus einem Erythema migrans in Berlin.

Among other manifestations, the following diseases caused by Borrelia burgdorferi in Europe are transmitted by ticks of the species ixodes ricinus: erythema migrans (EM), lymphadenosis benigna cutis (LBC), lymphocytic meningo-radiculitis (Bannwarth's syndrome), and acrodermatitis chronica atrophicans (ACA). We report on a female patient, who developed EM 10 days after a-tick bite in Berlin. Borrelia burgdorferi could be cultivated from a skin biopsy specimen taken from the periphery of the EM. The isolates were identified as Borrelia burgdorferi by indirect immunofluorescence using the monoclonal antibodies H 9724 and H 5332.

[A contribution to the technique of immunofluorescence in leptospirosis (author's transl)]. / Ein Beitrag zur Durchführung der Fluoreszenzserologie bei Leptospirose.

Mono- and polyvalent FITC-conjugates were prepared for detection of leptospires in artifically infected material. The organisms were concentrated by centrifugation and fixed onto glass slides after they had been mixed with serum or egg albumin. By this method, leptospires were detected down to a concentration of 10(2)-10(4) organisms/ml.

Serovars of Listeria monocytogenes and Listeria innocua from food.

The increase of listeriosis outbreaks in recent years has mainly been due to the consumption of contaminated dairy products. This prompted a revision of prevention and control measures. Cheese and other foods (meat, poultry meat) were investigated. For isolation, samples were prepared and investigated according to the recommendations of the FDA with some modifications including, in particular, sub-enrichment. Suspicious colonies were tested biochemically followed by serological identification with factor sera. Out of 100 chicken (95 broilers, 5 layers) Listeria monocytogenes was isolated from 85 carcases. The contamination rate for minced beef and pork (n = 76) was approximately 30%. That for selected ripened soft cheeses (n = 89) was 9%. The counts of Listeria in red meat were usually very low (approximately 10/g). Serovar 1/2a was predominant (78 out of 102 strains). Further serovars detected were: 1/2b, 1/2c, 3a, 4a, 4b, 4d. For comparison, isolated strains of L. monocytogenes and Listeria innocua were inoculated into chicken embryos. In contrast to the former, L. innocua did not kill the embryos.

Use of formaldehyde-PBS for serum dilution in the microscopic agglutination test (MAT) for leptospirosis.

Altogether, 431 sera (381 positive and 50 negative sera) were tested against different Leptospira serovars in the microscopic agglutination test (CMAT) using PBS with and without formaldehyde for comparative purposes. For the preparation of serum dilutions with formaldehyde-PBS, formaldehyde was added to PBS at a final concentration of 0.4%. When retested after storage, 234 from the 381 formerly positive sera gave positive, 68 doubtful and 79 negative results in the MAT. Out of the 234 sera with positive reaction in MAT, 212 (90.6%) showed positive reactions in the MAT with formaldehyde as well, 19 (8.1%) doubtful reactions and 3 (1.3%) became negative. All sera with negative reaction in the routine MAT were found to be negative in the MAT with formaldehyde as well.

[Listeriosis in the European brown hare in northern Germany]. / Listeriose beim Feldhasen in Norddeutschland.

During the years 1988-1997 listeriosis was detected in nine (2.4%) of 373 perished hares, in one of these cases calicivirus was additionally found. The listeriosis occurred sporadically. Granulomatous hepatosplenomegaly was the main lesion observed. Pregnancy is an important predisposing factor for the outbreak of listeriosis: six of the nine cases were hares post abortum or with retention of macerated foetuses in utero.--Six Listeria strains were serotyped and all belonged to serovar 1/2a.

Serological reactions of leptospirosis-positive (MAR and CFT) bovine sera in ELISA.

The collection of test sera for measuring ELISA results was composed of bovine sera with MAT titres of greater than or equal to 1:200 in the leptospirosis MAT and of greater than or equal to 1:5 in the CFT together with sera from a serologically negative and clinically non-suspicious cattle herd. To establish cut-off ODs, the geometric mean net-extinction of the negative serum collection plus 1, 2, and 3 standard deviations were calculated. By comparison of 3 different conjugates from rabbits, it was demonstrated that results from anti-total bovine Ig were superior to anti-IgG and anti-IgM conjugates. Considerations regarding sensitivity and specificity led to the recommendation to use a test serum dilution of 1:160, to apply anti-total bovine Ig conjugates, and to establish the cut-off OD at the geometric mean net-extinction of negative sera plus 3 standard deviations. Under such conditions, agreement between leptospirosis MAT/CFT positivity on the one side and ELISA positivity on the other was reached in 74%. This recommendation is made for cross-sectional studies but not for examinations of clinically suspicious cattle herds.

Prevalence of ticks in relation to their role as vector of Borrelia burgdorferi under autochthone conditions.

A total of 59 (78.7%) of 75 areas were found to be inhabitated by ticks; all the 4335 collected ticks were identified as Ixodes ricinus. Both nymphs and adults were found to be more active during the late spring and early summer months. Ticks of 29 recreation areas were found to be carrying spirochaetes. Considering the total number of 75 recreation areas examined and the total number of 59 areas inhabitated by ticks the percentage was 38.7 and 49.2 respectively. The positivity rate by dark field microscopy was 16.7% in 653 tick samples (single nymphs 8.8%, pooled nymph samples 21.5%, single females 10.9% and single males 10.8%). Overall positivity rate by culture examination of 245 samples was 22.8%. It was maximal in nymphs (24.7%) followed by males (21.1%) and females (19.7%). 10.2% of the 177 samples, found negative by DFM, were positive by this method. A positivity rate of 23.9% in 96 tick samples was found by IFAT. A total of 56 spirochaete-strains were obtained of which 51 could be maintained further; 50 strains were identified as Borrelia burgdorferi.