Seong-Eun Koh

Identification of the spotted fever group rickettsiae detected from Haemaphysalis longicornis in Korea.

Seven Haemaphysalis ticks were found positive in PCR assay of gltA gene to detect the spotted fever group (SFG) rickettsiae DNA from 100 ticks. The nucleotide sequence of 16S rRNA gene was determined from 5 ticks and compared to those of other Rickettsia strains. The nucleotide sequence from 4 ticks showed high homologies (99.7 to 100%) with that of R. japonica YH, and that from 1 tick (tick no. 48) was identical with that of R. rickettsii R, suggesting that SFG rickettsiae exists in Korea. This is the first documentation of SFG rickettsiae in Korea.

Differentiation of Rickettsiae by groEL Gene Analysis

ABSTRACT The nucleotide sequences (534 to 546 bp) of the groEL gene, which encodes the 60-kDa heat shock protein GroEL, from 15 rickettsial strains were determined and compared. In the phylogenetic tree created by the unweighted pair group method with arithmetic averages and the neighbor-joining method, rickettsial strains could be distinguished from Ehrlichia strains. Five spotted fever group strains, four typhus group strains, and six scrub typhus group (STG) strains were differentiated as distinct entities. Unlike gltA and ompA gene analyses, differentiation between members of the genus Rickettsia and the STG rickettsiae by groEL gene analysis was possible. In comparison with 16S rRNA gene analysis, the groEL gene has a higher degree of divergence among the rickettsiae. We therefore successfully developed rapid differentiation methods, PCR-restriction fragment length polymorphism analysis and a species-specific PCR, based on the groEL gene sequences. Four Korean isolates were identified by these methods and groEL gene analysis. The results suggest that the groEL gene is useful for the identification and characterization of rickettsiae.

Identification of the Coxiella sp. detected from Haemaphysalis longicornis ticks in Korea.

Two Haemaphysalis longicornis ticks were found positive in PCR assay of com‐1 gene to detect Coxiella burnetii DNA from 100 ticks. The nucleotide sequences of com‐1 and 16S rRNA gene were determined from 2 ticks and compared with those of other C. burnetii strains. The results suggest that H. longicornis harbor Coxiella sp. bacteria in Korea. Furthermore, icd, cbhE′, and cbbE′ genes are C. burnetii specific genes whereas com‐1 gene is Coxiella genus specific gene. This study gives the first documentation to prove the existence of Coxiella sp. in tick collected in Korea.

Dopaminergic differentiation of neural progenitors derived from placental mesenchymal stem cells in the brains of Parkinson's disease model rats and alleviation of asymmetric rotational behavior

Parkinsons disease (PD) is caused by the progressive loss of dopaminergic neurons in the mesencephalic substantia nigra and is accompanied by behavioral abnormalities. Pharmacological administration of L-dihydroxyphenylalanine (l-dopa) improves the abnormalities in the early phase of the illness, but numerous adverse effects hinder long-term administration. Transplantation of fetal mesencephalic tissues has been suggested as an alternative to l-dopa treatment; however, the use of human fetal tissues is controversial. Mesenchymal stem cells (MSCs) are capable of self-renewal and differentiation and are thus a promising substitute for fetal tissue for the replacement of diseased tissues or organs. Previously, this group isolated 17 independent MSCs from the first trimester human placenta (termed first trimester placental MSCs, or fPMSCs) and reported their successful in vitro differentiation into fPMSC-derived neural progenitors (fPMSC-NPs) (Park et al., Placenta 2011; 32:269-276). In the current study, the in vitro-generated fPMSC-NPs were transplanted into the striatum of a rat model of PD to evaluate whether they could undergo terminal differentiation and mediate behavioral recovery. As early as 2 weeks after transplantation, a minor but significant amelioration of rotational asymmetry was observed, and near-normal motor function was achieved at 24weeks. Immunohistochemical and positron emission tomography (PET) analyses provided experimental evidence for the dopaminergic differentiation of the transplanted progenitors. These results show that in vitro-generated fPMSC-NPs are capable of terminal differentiation in vivo and can attenuate motor defects associated with PD. Hence, the placenta is an auspicious source of stem cells for the therapeutic treatment of neurological disorders.

Neural progenitors generated from the mesenchymal stem cells of first-trimester human placenta matured in the hypoxic-ischemic rat brain and mediated restoration of locomotor activity

Term placenta is a great reservoir of mesenchymal stem cells (MSCs), however, the potential of the earlier placenta is largely unknown. In this report, we established 17 MSC lines from 19 first-trimester human placenta (fPMSC). fPMSC proliferated for 90-150 days in vitro and by enhanced cellular interaction, fPMSC differentiated into nestin-expressing neural progenitor cells (fPMSC-NP), accompanied by inductions of immature neuron-specific genes. Therapeutic effect of the fPMSC-NP was tested in the animal model of hypoxia-ischemia (HI) which was devastating to dopaminergic neurons and to locomotor activity. Improvement of motor activity was evident as early as 2 weeks after transplantation of the fPMSC-NP into bilateral striatum and became indistinguishable from that of the age-matched normal animals by 8 weeks but no spontaneous recovery was observed in the control-grafted animals. Immunohistochemical analyses revealed that the implanted fPMSC-NP matured into ectodermal cells including the tyrosine hydroxylase (TH)-expressing neurons in the recipient striatum. So, the improved motor behavior was likely due to the dopaminergic differentiation of the implanted fPMSC-NP in the dopaminergic-denervated host brain. Based on this result, we propose that progenitors may be more advantageous than the terminally differentiated cells for the purpose of cell replacement therapies since the progenitors are easily obtainable and are expected to be more pliable to the new environment.

Effects of Extracorporeal Shock Wave Therapy on Spasticity in Patients after Brain Injury: A Meta-analysis.

[Purpose] The purpose of this meta-analysis was to assess the effects of extracorporeal shock wave therapy (ESWT) on reducing spasticity immediately and 4 weeks after application of ESWT. [Subjects and Methods] We searched PubMed, TCL, Embase, and Scopus from their inception dates through June 2013. The key words “muscle hypertonia OR spasticity” were used for spasticity, and the key words “shock wave OR ESWT” were used for ESWT. Five studies were ultimately included in the meta-analysis. [Results] The Modified Ashworth Scale (MAS) grade was significantly improved immediately after ESWT compared with the baseline values (standardized mean difference [SMD], −0.792; 95% confidence interval [CI], −1.001 to −0.583). The MAS grade at four weeks after ESWT was also significantly improved compared with the baseline values (SMD, −0.735; 95% CI, −0.951 to −0.519). [Conclusion] ESWT has a significant effect on improving spasticity. Further standardization of treatment protocols including treatment intervals and intensities needs to be established and long-term follow up studies are needed.

Evaluation of groEL Gene Analysis for Identification of Borrelia burgdorferi Sensu Lato

ABSTRACT The nucleotide sequences of the groEL genes, the flagellin genes, and the 16S rRNA genes from 22 reference strains of Borrelia were compared. groEL sequence analysis is useful not only in interspecies differentiation but also in intraspecies differentiation of Borrelia afzelii and Borrelia garinii isolates.

Differentiation of Borrelia burgdorferi sensu lato through groEL gene analysis

The nucleotide sequences (310 bp) of the groEL gene, which encode the 60-kDa heat shock protein GroEL from 31 reference strains of Borrelia were determined and compared. More than 92.3% similarity was observed among Borrelia burgdorferi sensu lato strains. In the phylogenetic tree constructed with the maximum-likelihood method, each species of B. burgdorferi sensu lato was differentiated as a distinct entity. We developed polymerase chain reaction-restriction fragment length polymorphism analysis using a specific single amino acid variation [N(213) (AAT)-->S (AGC or AGT)] between B. burgdorferi sensu stricto strains and the other B. burgdorferi sensu lato strains. These results showed that the groEL gene is useful for differentiation of B. burgdorferi sensu lato.

Comparison of human first and third trimester placental mesenchymal stem cell

Placenta mesenchymal stem cells (PMSCs) have the characteristic features of stem cells including renewability in vitro, surface expression, differentiation potency and ability to adhere to the culture surface. PMSCs expressed genes are normally found in the embryonic tissues before the onset of gastrulation, indicating multipotency. However, the stemness can depend on the stages of the placenta from which the cells were isolated. PMSCs were isolated from two different stages of placenta for comparison, that is the first and third trimesters. Both sets had very similar patterns of surface expression as CD44, CD73, CD90 and CD105, and of self renewability in vitro. Expressions of pluripotency‐coupled genes were also confirmed in both sets of cells; however, there was a significant difference in the expression levels: fPMSC (mesenchymal stem cells isolated from the first trimester human placenta) being 2–11‐fold higher than tPMSC (mesenchymal stem cells isolated from the third trimester human placenta). Possibly due to the difference in the expression levels of the pluripotency‐related genes, induction of genes specific to the ectodermal tissues were more prominent in fPMSC than tPMSC after induced differentiation.

The Relation between Postvoid Residual and Occurrence of Urinary Tract Infection after Stroke in Rehabilitation Unit.

Objective To determine the relation between postvoid residual (PVR) and the occurrence of urinary tract infection (UTI) in stroke patients. Method One hundred and eighty-eight stroke patients who were admitted to an inpatient rehabilitation unit and who did not have UTI on admission (105 males, 83 females, mean age 67.1 years) were included in this study. The PVR was measured 3 times within 72 hours after admission. Mean PVR, demographic variables, K-MMSE (Korean Mini-Mental State Examination), initial K-MBI (Korean Modified Barthel Index), Foley catheter indwelling time and stroke type were defined and the relation to the occurrence of UTI was analyzed. Results UTI occurred in 74 patients (39.4%) during admission to the rehabilitation unit. There were significant differences between the UTI and non-UTI groups in K-MMSE, K-MBI, Foley catheter indwelling time (p<0.01). However, age, gender, stroke location and type were not associated. The occurrence of UTI was 4.87 times higher in the patients with a mean PVR over 100 ml than in those with a mean PVR <100 ml. The mean PVR was 106.5 ml in the UTI group, while it was 62.7 ml in the non-UTI group (p<0.01). PVR was not associated with age. Conclusion The UTI rate is higher when the mean PVR is over 100 ml irrespective of gender and age. Close monitoring of PVR and appropriate intervention is needed to reduce the occurrence of UTI in stroke patients.