Effects of 60 Hz electromagnetic field exposure on testicular germ cell apoptosis in mice / 亚洲男科学杂志(英文版)

<p><b>AIM</b>To evaluate the effects of 60 Hz extremely low frequency (ELF) elelctromagnetic field (EMF) exposure on germ cell apoptosis in the testis of mice.</p><p><b>METHODS</b>Adult male BALB/c mice (7 weeks of age) were exposed to a 60 Hz EMF of 0.1 mT or 0.5 mT for 24 h/day. A sham-exposed group served as the control. After 8 weeks of exposure, the mice were sacrificed. Germ cell apoptosis in the testis was assessed by histopathological examination, the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) and flow cytometric examination of isolated spermatogenic cells stained with 7 aminoactinomycin D (7-AAD).</p><p><b>RESULTS</b>EMF exposure did not significantly affect the body and testis weights, but significantly increased the incidence of germ cell death. The distinguishing morphological feature of EMF exposure was a decrement in the number of well organized seminiferous tubules. Quantitative analysis of TUNEL-positive germ cells showed a significantly higher apoptotic rate in the 0.5 mT exposed mice than that in the sham controls (P<0.05), while the difference between the two exposed groups was insignificant. The TUNEL-positive cells were mainly spermatogonia. In flow cytometry analysis, the percentage of live cells [forward scatter count (FSC)(high)7-AAD(-)] was lower in the exposed groups than that in the controls (Figure 5A), but the decrease in viability was not statistically significant.</p><p><b>CONCLUSION</b>Continuous exposure to ELF EMF may induce testicular germ cell apoptosis in mice.</p>

Characterization of Korean Leptospira interrogans Isolates by Pulsed-Field Gel Electrophoresis of Not I Digests of DNA / 감염과화학요법

BACKGROUND: Many strains of Leptospira interrogans have been isolated in Korea since 1984. Most isolates were identified as serovar lai by serological methods. The pulsed field gel electrophoresis (PFGE) patterns of Korean isolates have not been investigated currently. METHODS: 29 reference strains and 29 Korean isolates of Leptospira interrogans were characterized by PFGE. Chromosomes were digested by the Not I restriction enzyme and subsequently PFGE was performed in CHEF-DRII (Bio Rad Lab) with 3 pulse times (30 seconds 13 hours, 60 seconds 13 hours, 120 seconds 14 hours) at 150 V (4.5 V/cm). RESULTS: 12 serogroup reference strains and most 17 serovars reference strains in the serogroup Icterohaemoffhagie showed the unique Not I restriction patterns. Most isolates identified serologically as serovar lai showed the same PFGE patterns as the serovar lai reference strain. The strain HM3 and 18R identified serologically as new serovars yeonchon and hongchon respectively showed the same PFGE patterns as serovar lai. The strain AP31, CH88-19 and NR13 that were different from serovar lai by serological methods showed the PFGE patterns indistinguishable from serovar lai reference strain. The strain HY2 that was identified as serovar lai, and the strain 30R that was different from serovar lai serologically showed the PFGE patterns slightly different from serovar lai reference strain. CONCLUSION: The PFGE profile of most Korean isolates Leptospira interrogans serologically identified as serovar lai is identical to the reference strain serovar lai. PFGE analysis thus may be applied to identify serovar of isolates and to investigate the genetic diversity of related serovar.

Characterization of Korean Leptospira interrogans Isolates by Pulsed-Field Gel Electrophoresis of Not I Digests of DNA / 감염과화학요법

BACKGROUND: Many strains of Leptospira interrogans have been isolated in Korea since 1984. Most isolates were identified as serovar lai by serological methods. The pulsed field gel electrophoresis (PFGE) patterns of Korean isolates have not been investigated currently. METHODS: 29 reference strains and 29 Korean isolates of Leptospira interrogans were characterized by PFGE. Chromosomes were digested by the Not I restriction enzyme and subsequently PFGE was performed in CHEF-DRII (Bio Rad Lab) with 3 pulse times (30 seconds 13 hours, 60 seconds 13 hours, 120 seconds 14 hours) at 150 V (4.5 V/cm). RESULTS: 12 serogroup reference strains and most 17 serovars reference strains in the serogroup Icterohaemoffhagie showed the unique Not I restriction patterns. Most isolates identified serologically as serovar lai showed the same PFGE patterns as the serovar lai reference strain. The strain HM3 and 18R identified serologically as new serovars yeonchon and hongchon respectively showed the same PFGE patterns as serovar lai. The strain AP31, CH88-19 and NR13 that were different from serovar lai by serological methods showed the PFGE patterns indistinguishable from serovar lai reference strain. The strain HY2 that was identified as serovar lai, and the strain 30R that was different from serovar lai serologically showed the PFGE patterns slightly different from serovar lai reference strain. CONCLUSION: The PFGE profile of most Korean isolates Leptospira interrogans serologically identified as serovar lai is identical to the reference strain serovar lai. PFGE analysis thus may be applied to identify serovar of isolates and to investigate the genetic diversity of related serovar.

Detection of Leptospiral DNA from Field Rodents by PCR

Leptospirosis has been one of important epidemic diseases in Korea since 1984. Wild rodents, mostly Apodemus agrarius, served the important source of infection especially in harvest season in rural areas of Korea. Prevalence of Leptospira spp. infection in field rodents were investigated by detecting leptospiral DNA from rodent kidney. Among 108 rodents collected from various areas in 1998, leptospiral DNA were detected from 7 rodents (6.48%). Among 104 rodents, Apodemus agrarius, captured from Yeonchon and Paju area in 2001 and 2002, leptospiral DNA were detected from 6 rodents (5.76%). No leptospiral DNA was detected from 23 rodonts (Apodemus peninsulae 16, Apodemus agrarius 2 and Eothenomys regulus 5) captured in Odae mountain area in 1998.

Characterization of a Species-specific Antigen in Rickettsia typhi

Murine typhus is an acute febrile illness caused by Rickettsia typhi. It is one of the four major acute febrile illnesses in Korea during autumn. To study a species-specific antigen of R. typhi, two clinical isolates (87-91 and 87-100) and two reference strains (VR-144 and VR-738) were analyzed by mouse antisera and monoclonal antibodies (MAbs). On SDS- polyacrylamide gel electrophoresis (PAGE), R. typhi showed major antigen bands of 135, 80, 75, 64, 47, 22, and 19 kDa and these bands differed with those of other species. On Western blot analysis, the MAbs reacting only with R. typhi could only detect 135 kDa protein. The 135 kDa protein appeared to be the species-specific antigen. Other MAbs showing cross-reactivity with R. prowazekii reacted with 135 kDa protein in fresh culture supernatant of R. typhi infected host cell. However, the cross-reacting antibody did also react with smaller protein bands, most of which seem to be degradation products of the 135 kDa protein since they increase in old protein stocks purified from R. typhi harvested from infected host cell. These suggest that 135 kDa protein is unstable and the R. typhi specific epitopes are located at the regions of 135 kDa protein that are removed when the protein is degraded. The 135 kDa protein or its specific and stable recombinant protein would serve an important target for the development of vaccine and specific diagnostic antigen.