PURPOSE: To examine the fate of muscle-derived stem cells (MDSC) after injection into different host conditions and provide an insight for their mechanism of action. MATERIALS AND METHODS: MDSCs differentiated in vitro towards the endothelial lineage and transfected with lentivirus tagged with green fluorescent protein (GFP) were injected into two animal models mimicking vascular diseases: hindlimb ischemia and carotid injury models. Injected cells were tracked at the site of injection and in remote organs by harvesting the respective tissues at different time intervals and performing immunofluorescent histological analyses. Stem cell survival was quantified at the site of injection for up to 4 weeks. RESULTS: MDSCs were successfully tagged with fluorescent material GFP and showed successful implantation into the respective injection sites. These cells showed a higher affinity to implant in blood vessel walls as shown by double fluorescent co-stain with CD31. Quantification of stem cell survival showed a time-dependent decrease from day 3 to 4 weeks (survival rate normalized against day 3 was 72.0% at 1 week, 26.8% at 2 weeks and 2.4% at 4 weeks). Stem cells were also fo und in distant organs, especially the kidneys and liver, which survived up to 4 weeks. CONCLUSION: MDSCs were successfully tracked in different vascular disease models, and their fate was assessed in terms of cell survival and distribution. Better understanding of the donor cell properties, including their interaction with the host conditions and their mechanism of action, are needed to enhance cell survival and achieve improved outcomes.
Adult Stem Cells ; Animals ; Blood Vessels ; Cell Survival ; Hindlimb ; Humans ; Ischemia ; Kidney ; Lentivirus ; Liver ; Models, Animal ; Stem Cell Niche ; Stem Cells* ; Tissue Donors ; Vascular Diseases

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No abstract available.

Purpose: Stem cell-based therapies are considered an alternative approach for critical limb ischemia (CLI) patients with limited or exhausted options, yet their clinical use is limited by the lack of sustainability and unclear mechanism of action.In this study, a substance P-conjugated scaffold was injected with mesenchymal stem cells (MSCs) into an animal model of CLI to verify whether angiogenesis could be enhanced. Methods: A self-assembling peptide (SAP) was conjugated with substance P, known to have the ability to recruit host stem cells into the site of action. This SAP was injected with MSCs into ischemic hindlimbs of rats, and the presence of MSCs was verified by immunohistochemical (IHC) staining of MSC-specific markers at days 7, 14, and 28. The degree of angiogenesis, cell apoptosis, and fibrosis was also quantified. Results: Substance P-conjugated SAP was able to recruit intrinsic MSCs into the ischemic site of action. When injected in combination with MSCs, the presence of both injected and recruited MSCs was found in the ischemic tissues by double IHC staining. This in turn led to a higher degree of angiogenesis, less cell apoptosis, and less tissue fibrosis compared to the other groups at all time points. Conclusion The combination of substance P-conjugated SAP and MSCs was able to enhance angiogenesis and tissue repair, which was achieved by the additive effect from exogenously administered and intrinsically recruited MSCs. This scaffold-based intrinsic recruitment approach could be a viable option to enhance the therapeutic effects in patients with CLI.

Aortic aneurysm is a common and life-threatening disease that can cause death from rupture. Current therapeutic options are limited to surgical or endovascular procedures because no pharmacological approaches have been proven to decrease the chance of expansion or rupture. The best approach to the management of aortic aneurysm would be the understanding and prevention of the processes involved in disease occurrence, progression, and rupture. There is a need for animal models that can reproduce the pathophysiological features of human aortic aneurysm, and several such models have been studied. This review will emphasize recent advances in animal models used in the determination of mechanisms and treatments of aortic aneurysms.
Aneurysm ; Aorta ; Aortic Aneurysm* ; Endovascular Procedures ; Humans ; Models, Animal* ; Rupture

PURPOSE: We compared the reproducibility of 201Tl and 99mTc-sestamibi (MIBI) gated SPECT measurement of myocardial function using the Germano algorithm. MATERIALS AND METHODS: Gated SPECT acquisition was repeated in the same position in 30 patients who received 201Tl and in 26 who received 99mTc-MIBI. The quantification of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) on 201Tl and 99mTc-MIBI gated SPECT was processed independently using Cedars quantitative gated SPECT software. The reproducibility of the assessment of myocardial function on 201Tl gated SPECT was compared with that of 99mTc-MIBI gated SPECT. RESULTS: Correlation between the two measurements for volumes and EF was excellent by the repeated gated SPECT studies of 201Tl (r=0.928 to 0.986; p<0.05) and 99mTc-MIBI (r=0.979 to 0.997; p<0.05). However, Bland Altman analysis revealed the 95% limits of agreement (2 SD) for volumes and EF were tighter by repeated 99mTc-MIBI gated SPECT (EDV: 14.1 ml, ESV: 9.4 ml and EF: 5.5%) than by repeated 201Tl gated SPECT (EDV: 24.1 ml, ESV: 18.6 ml and EF: 10.3%). The root mean square (RMS) values of the coefficient of variation (CV) for volumes and EFs were smaller by repeated 99mTc-MIBI gated SPECT (EDV: 2.1 ml, ESV: 2.7 ml and EF: 2.3%) than by repeated 201Tl gated SPECT (EDV: 3.2 ml, ESV: 3.5 ml and EF: 5.2%). CONCLUSION: 99mTc-MIBI provides more reproducible volumes and EF than 201Tl on repeated acquisition gated SPECT. 99mTc-MIBI gated SPECT is the preferable method for the clinical monitoring of myocardial function.
Humans ; Perfusion* ; Technetium Tc 99m Sestamibi ; Tomography, Emission-Computed, Single-Photon*

Because of various current problems and issues which are low health insurance medical fee of National Health Insurance Corporation, extreme competition with very large general hospitals, new supply of more than of 3,000 new doctors, many medical practitioner's offices who are suffering management difficulties are increasing. In order to investigate their current overall management situations, we made this study through statistical extraction procedures with the sample population of the medical practitioners which are registered in Korean Medical Association and subsequently we made the study with 1,031 selected cases. The average number of patients is 53.6 patients per day. 44.4% of the medical practitioners' offices are working at night and legal holidays and 8.5% are working at Sunday. Average working hours is 50.1 hours per week, which greatly exceeds 40 hours per week that is regulated in the Labor Standards Act. According to the management performance analysis of those medical clinics through profit and loss statements, average total annual sales revenue in 2010 fiscal year was 444,167,867 KRW, the expenses were 314,217,081 KRW and the earnings before taxes was 129,940,786 KRW. The average net profit (earnings before taxes) of the director of the medical practitioners' offices was 122,337,868 KRW per year and 10,194,822 KRW per month. According to the study results, we have found that we need to increase doctor's bill for outpatient, and establishment and its improvement of medical service delivery systems and classification standards of medical services for first and succeeding outpatients. Considering overall results of the study, readjustment of outpatients' treatment fees and reestablishment of more efficient medical service delivery systems which require the first medical service is to be provided properly should be realized in order to improve the management performance of the medical practitioners' offices.
Commerce ; Fees and Charges ; Fees, Medical ; Holidays ; Hospitals, General ; Humans ; Insurance, Health ; Korea ; National Health Programs ; Outpatients ; Stress, Psychological ; Taxes

Greater than its influence on the medical practitioner's individual ability is the National Health Insurance System's influence on the management of medical practitioners' offices in Korea. However, despite the important effect health insurance exerts on the income of medical clinics, recently, the financial difficulties of medical clinics have often become an issue, and financial difficulty has been aggravated as much as a solution has been sought. The current state of the overall management of medical clinics was investigated to understand the factors influencing the sales and expenses in their management. A questionnaire was completed by 1,009 physicians registered in the Korean Medical Association who were participating in a statistical extraction course. As a result of the study, the factors influencing the total revenue and total expenditures of medical clinics, such as increases in the total number of doctors, increasing numbers of outpatients, the size of the medical office, medical disputes, and clinical specialties (based on the first medical treatment) showed statistical significance. In conclusion, in order to improve medical clinic management, a health insurance medical fee should be more reasonably fixed, a medical transfer system should be reestablished, and a cooperative strategy should be created for medical clinics and general hospitals in order to attract patients. As a result, low cost and highly efficient medical services could be provided and the satisfaction of patients improved.
Commerce ; Dissent and Disputes ; Fees, Medical ; Health Expenditures ; Hospitals, General ; Humans ; Insurance ; Insurance, Health ; Korea ; National Health Programs ; Outpatients ; Physicians, Primary Care ; Primary Health Care ; Surveys and Questionnaires

BACKGROUND: Nitric oxide (NO), a cytotoxic molecule is produced in various tissues including tumor cells during interleukin-2 (IL-2) therapy . Lymphokine-activated killer (LAK) cells are induced during IL-2 therapy, and have cytotoxic activity against tumor cells. The current study investigated the effects of NO synthesized in target cells or exposure of target cells to NO on the sensitivity of target cells to LAK cell cytotoxicity. METHODS: Cytotoxicity was measured using 4 h chromium release assays. LAK cells which were induced by a 4 day incubation of BALB/c mouse splenocytes with IL-2 (6,000 IU/mL) were employed as effector cells. RD-995 skin tumor cells originated from a C3H/HeN mouse were employed as target cells. NO synthesis in target cells was induced by a 24 h incubation of RD-995 cells with IFN gamma (25 U/mL), TNF (50 U/mL) and IL-1 (20 U/mL). S-nitrosyl acetylpenicillamine (SNAP), an NO donor, was used to expose target cells to NO. N(G) -monomethyl-L-arginine (MLA) and carboxy-PTIO were added during cytotoxicity assays to inhibit NO synthesis, and to scavenge NO produced by target cells, respectively. RESULTS: Sensitivity of NO-producing RD-995 cells to LAK cell cytotoxicity was decreased by addition of MLA and carboxy-PTIO during cytotoxicity assays. However, the two reagents had no effect on the sensitivity of non-NO-producing RD-995 cells. Pretreatment of RD-995 target cells with SNAP increased the sensitivity in comparison with untreated cells. CONCLUSIONS: Sensitivity of target cells to LAK cell cytotoxicity is increased by target cell NO synthesis or exposure to NO. Further studies are needed to evaluate whether these in vitro results have relevance to in vivo phenomena.
Animals ; Chromium ; Humans ; Indicators and Reagents ; Interleukin-1 ; Interleukin-2 ; Killer Cells, Lymphokine-Activated* ; Lymphocytes ; Mice ; Nitric Oxide* ; Skin ; Tissue Donors

BACKGROUND AND OBJECTIVES: Even patients with compensated peripheral vestibular dysfunction may report a sense of disequilibrium during daily activities, which often fail conventional vestibular function tests as attentional demand required for postural control may increase in these patients. The study aims to assess the feasibility of dual task test using concurrent cognitive tasks in a modified clinical test of sensory interaction on balance (mCTSIB) to measure increased attentional demand for posture control. SUBJECTS AND METHOD: Nineteen patients suspected with chronic dizziness were recruited by history reviews and physical examinations. Data for center of pressure (COP) variability and mean velocity during mCTSIB on a force long plate were analyzed, and time taken to react to the auditory stimuli were used to measure the attentional demand required for adequate postural control during platform perturbation. RESULTS: The mean COP range and velocity during mCTSIB were comparable between single and dual task conditions in patients with dizziness. Reaction time (RT) to auditory stimulus of 1 kHz pure tone in patients with chronic dizziness was also comparable to normal subjects. Interestingly, there was a tendency for increased RT in patients with documented caloric weakness, suggesting that attentional demand is increased in these patients. CONCLUSION: RT of dual task tests using auditory stimuli during mCTSIB may provide additional information about increased attentional demand for postural control in patients with vestibular dysfunction.
Dizziness* ; Humans ; Methods ; Physical Examination ; Posture ; Reaction Time ; Task Performance and Analysis ; Vestibular Diseases ; Vestibular Function Tests