Electron bunch timing with femtosecond precision in a superconducting free-electron laser.

High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.

Prevalence of antibodies to hepatitis C virus in patients on peritoneal dialysis--a multicenter study.

The prevalence of antibodies to the hepatitis C virus (HCV) was determined in 333 peritoneal dialysis (PD) patients from 10 German dialysis units, using an enzyme-linked immunosorbent assay of the second generation (ELISA 2nd gen) which detects antibodies to a structural (C22) and to non-structural (C33c, C100, 5-1-1) recombinant antigens of HCV. Sera from 18/333 (5.4%) patients were anti-HCV positive versus 11/295 (3.7%) when the sera were tested by an ELISA of the first generation (ELISA 1st gen) containing only a nonstructural antigen (C100). In the 18 sera positive by ELISA 2nd gen, antibodies against at least one viral protein were found by recombinant immunoblot assay (RIBA) in 15/333 (4.5%) patients. In the sera of 11/15 (73.3%) patients HCV RNA was detected by nested PCR. Epidemiological evaluation of the patients revealed that the prevalence of anti-HCV was correlated to the female sex (p = 0.005), presence of anti-HBc (p = 0.006), duration of total dialysis (hemodialysis HD and PD) (p = 0.012), duration of HD alone (p = 0.025) and previous renal transplantation (p < 0.001). Only a weak correlation was found to blood transfusions (p = 0.041) and elevation of serum ALT concentration (p = 0.055). But no correlation was found to diagnoses of renal failure (p = 0.129), duration of PD (p = 0.963) and past surgical procedures (p = 1.0). Four of nine peritoneal dialysates of anti-HCV positive patients were found positive for HCV RNA.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of hepatitis C virus infections in dialysis patients and their contacts using a second generation enzymed-linked immunosorbent assay.

The prevalence of antibodies to the hepatitis C virus (HCV) was determined in 498 hemodialysis patients from three german dialysis units, 121 staff members and 42 family members using an enzyme-linked immunosorbent assay (ELISA) of the second generation which detects antibodies to a structural (C22) and to non-structural (C33c, C100, 5-1-1) recombinant antigens to HCV. Using the second generation ELISA 115 patients (23.1%) were anti-HCV positive versus 77 (15.5%) when sera were tested by an ELISA of the first generation containing only a non-structural antigen (C100). In 34 of these 40 discordant sera antibodies against at least one viral protein was found by a recombinant immunoblot assay. Of 5 sera containing antibodies to only one viral protein (C22) 3 were HCV RNA positive by polymerase chain reaction. Epidemiological evaluation of the patients revealed that the prevalence of anti-HCV was correlated to the duration of dialysis but not to the number of blood transfusions. Of 121 staff members 2 (1.6%) and 2 of 42 family members (4.7%) were positive indicating a low risk of the patients' contacts of acquiring HCV infection.

Long-term persistence of hepatitis C virus antibodies in a single source outbreak.

The occurrence of antibodies to hepatitis C virus (HCV) was investigated in 81 patients who developed hepatitis non-A, non-B (HNANB) after parenteral administration of contaminated immunoglobulin to prevent Rh sensitization. Sera from 74 of the 81 patients (89.9%) were anti-HCV positive at either 6-12 months or 9-10 years after administration of immunoglobulin. Sera were not available from any patients at either of the times: however, 52 of 56 sera (92.9%) were anti-HCV positive 6-12 months after use of immunoglobulin, and anti-HCV was present in 45 of 65 sera (69.2%) 9-10 years after immunoglobulin treatment. Of the latter, only two of 13 (15.4%) sera from patients who recovered from hepatitis were anti-HCV positive, whereas 43 of 52 patients (82.7%) with chronic disease were anti-HCV positive. The ELISA using a recombinant antigen was found a good detector as marker for a HCV infection because 90% of patients infected by a common source became anti-HCV positive. However, 10 years after infection most patients who did not develop chronic disease no longer had detectable antibodies.

[Lyme borreliosis in South Germany. Epidemiologic data on the incidence of cases and on the epidemiology of ticks (Ixodes ricinus) carrying Borrelia burgdorferi]. / Lyme-Borreliose in Süddeutschland. Epidemiologische Daten zum Auftreten von Erkrankungsfällen sowie zur Durchseuchung von Zecken (Ixodes ricinus) mit Borrelia burgdorferi.

Among 2403 ticks (Ixodes ricinus) tested in 1985 for Borrelia 328 (13.6%) were carriers (adults about 20%, nymphs about 10%, larvae about 1%). The highest prevalence of infected ticks was among adult ticks in the Isar region north of Munich (33.8%). Among 9383 persons whose serum had been examined by fluorescence serology in 1985 and 1986, 1035 (11%) had raised Borrelia-specific IgG and/or IgM antibodies greater than or equal to 1:64. In 18.7% only IgM antibodies were demonstrated. Among 375 proven cases there were 78 with erythema migrans, 211 with neurological signs, 48 with Lyme arthritis and 36 with acrodermatitis. Seasonal incidence peaks were in June-August for erythema migrans, July-September for neurological signs, with no clear-cut seasonal peaks with Lyme arthritis and acrodermatitis. The incubation time for 80% of cases of each abnormality was 5-29 days for erythema migrans, 20-59 for neurological signs and 2-8 months for Lyme arthritis. Erythema migrans was most frequent among those aged 30-60 years, neurological signs among children and juveniles up to 20 years and those aged 40 to 70 years, Lyme arthritis among those aged 30-60 years, and acrodermatitis among those aged 40-80 years. Significantly more women than men developed acrodermatitis.

Selective pressure of antistaphylococcal chemotherapeutics in favour of Pseudomonas aeruginosa in cystic fibrosis.

Pseudomonas aeruginosa is insensitive against the majority of oral chemotherapeutics active against staphylococci. During application of such compounds in patients colonized by P. aeruginosa the concentration of P. aeruginosa increased in the majority of treatment episodes by factors between 2.5 and 50000. So, from a microbiological point of view the application of purely antistaphylococcal drugs should not be used prophylactically against staphylococci.

Sensitivity and specificity of commercial ELISA kits for screening anti-LAV/HTLV III.

Two panels consisting of 236 and 258 anti-LAV/HTLV III positive and 64 and 50 negative sera, respectively (determined in Western blots), were tested with 8 different, commercially available ELISA test kits for detecting LAV/HTLV III antibodies (Abbott, Dupont, Electro-Nucleonics, Litton, Organon, Pasteur, Sorin, Wellcome). Positive sera were selected for levels of antibodies ranging from average to very high, and the negative sera included both negative sera and sera with antibodies to cellular components such as HLA antigens or nuclear membranes. In examination of the 2 panels, the sensitivity of the tests ranged from 97.2 to 100%, and the specificity from 70.0 to 100%. No test was ideal.

[Increase in the prevalence of antibodies against LAV/HTLV III in drug addicts in West Germany]. / Zunahme der Prävalenz von Antikörpern gegen LAV/HTLV III bei Drogenabhängigen in der Bundesrepublik Deutschland.

Sera obtained from 927 drug addicts in 1983 to 1985 were tested for antibodies against LAV/HTLV-III. There was a steadily rising proportion of positive results: 10.1% in 1983, 17.6% in 1984 and 23.9% in 1985. In each year the prevalence of anti-LAV/HTLV-III was higher among female than male addicts. No increased proportion of positive results was demonstrable in relation to age. Among 152 sera from 1983/84, hepatitis-B markers were found in 72 (43.7%), of whom 10 (14%) were also anti-LAV/HTLV-III positive. Among hepatitis-B marker-negative sera there were 8 (6%) which were also anti-LAV/HTLV-III positive. The prevalence of anti-LAV/HTLV-III in drug addicts in prisons, rehabilitation centres, hospitals and medical practices was similar. There is a danger that prostitution by addicts for obtaining drugs will cause a penetration of LAV/HTLV-III in the rest of the population.

Clinical evaluation of a recombinant hepatitis B vaccine.

Recombinant hepatitis B vaccine prepared from antigen expressed in yeast was given to 30 healthy young volunteers. Seroconversion rates and anti-HBs levels were compared with those in a control group matched for age and sex who had received plasma-derived hepatitis B vaccine. 4 weeks after the third immunisation results were similar in the two groups. In the recombinant vaccine group the immune response developed more slowly during the early phase and seroconversion rates and mean anti-HBs levels were slightly lower in males; this probably reflects use of a lower dose of recombinant vaccine (10 micrograms compared with 20 micrograms of the plasma vaccine). Side-effects were slight and antibody titres against Candida albicans were not increased in recipients of the recombinant vaccine.

Passive/active immunization against hepatitis B.

No differences in eventual immune-response rates were found between 325 subjects immunized passively/actively against hepatitis B and a control group of 108 subjects vaccinated only actively. The geometric mean titers of antibodies to hepatitis B surface antigen were nearly identical in controls and in a group of 87 individuals immunized passively/actively with the same vaccine lot. Lower geometric mean titers of antibodies to hepatitis B surface antigen were seen in 238 individuals who were vaccinated passively/actively with a different vaccine lot, a difference that may be explained by a somewhat lower immunogenicity in this particular lot. The mean half-life of hepatitis B immunoglobulin was calculated as 24.8 days, and in approximately 90% of vaccines 300,000 mIU of hepatitis B immunoglobulin provided protection until an active immune response had developed.

Evaluation of a reduced dose of hepatitis B vaccine administered intradermally.

Intradermal inoculation of hepatitis B vaccine (HBsAg subtype adw) caused no side effects, but the vaccine was less immunogenic than following intramuscular administration. Intradermal inoculation does not, therefore, offer a major advantage to the generally used intramuscular immunization. A single multisite intradermal administration of a reduced dose of vaccine did not result in a more rapid seroconversion compared to intramuscular inoculation. Although the antibody levels were similar after two intradermal or intradermal or intramuscular injections given 1 month apart, the booster (third injection) at 6 months resulted in anti-HBs levels that were about 10 times higher following intramuscular inoculation as compared to intradermal. All persons immunized developed anti-HBs. The levels of anti-HBs (a and w) were about 30-40% of the total anti-HBs, and the proportion did not change significantly during the course of immunization. Cross-protection against all HBV strains is thus also assured after intradermal administration of vaccine containing only one HBsAg subtype (adw). A skin reaction was elicited only in a small proportion of anti-HBs-positive individuals, and the reaction correlated roughly with the immune responses.