Oh-Jang Kwon

Preemptive Living-Donor Renal Transplantation: Outcome and Clinical Advantages

INTRODUCTION Kidney transplant recipients have a higher quality of life and consume fewer health care resources compared with patients on dialysis. However, optimal timing of transplantation has been controversial. Recent studies have clearly demonstrated that preemptive renal transplantation is associated with better graft survival, lower complications, and better cost-effective outcomes. We evaluated differential effects on long-term outcomes according to dialysis type/duration versus no dialysis. MATERIALS AND METHODS We retrospectively analyzed 499 cases of first living-donor kidney transplantations performed in our center from January 1990 to January 2007. We compared 3 groups according to graft survival, acute and chronic rejection, postoperative complication, and delayed graft function rates. The mean duration of follow-up was 119.1 +/- 47.2 months. RESULTS Among 499 cases, 81 cases were preemptive renal transplantations with 418 cases hemodialysis [HD], 343 cases, peritoneal dialysis [PD] 75 cases) performed after dialysis. The 1-, 5-, and 10-year graft survival rates were 98.8%, 89.5%, 79.4% among the preemptive renal transplantation group and 92.4%, 78.2%, and 69.2% and 85.3%, 74.5%, and 68.2% (P = .03) in the dialysis groups (HD, PD), respectively. The differential effect of pretransplantation HD or PD was not significant. However, the graft survival rates in the HD group were not significantly higher than the PD group (P = .61). The duration of dialysis was not associated with graft survival. CONCLUSION We suggest that preemptive renal transplantation should be the first choice of treatment for patients with end-stage renal disease.

Long distance fiber Bragg grating strain sensor interrogation using a high speed Raman-based Fourier domain mode-locked fiber laser with recycled residual Raman pump.

We propose a novel fiber Bragg grating (FBG) sensor interrogation using a Raman-based Fourier-domain mode locking (FDML) fiber laser for a high speed and long distance measurement. A residual Raman pump after the generation of the Raman-based FDML fiber laser is recycled for secondary signal amplification in a 2-m erbium-doped fiber (EDF) to further enhance the output power. The chromatic dispersion is precisely controlled to suppress the phase noise in the FDML laser cavity, resulting in the improvement of an R-number of 1.43 mm/dB. After recycling residual pump, we achieve the 40-km round trip transmission of the sensing probe signal with a high scan rate of 30.8 kHz. With 205-mW residual pump power, the bandwidth and the maximum gain are measured to be more than 50 nm, 10.3 dB at 1550 nm, respectively. The sensitivity of the proposed Raman-based FDML fiber laser to strain is also measured, which are 0.81 pm/μstrain in the spectral domain and 0.19 ns/μstrain in the time domain, respectively.

Influence of Diverse Atmospheric Conditions on Optical Properties of a Pulse Laser in a Time-of-Flight Laser Range Finder

We investigate the propagation characteristics of a pulse laser in a time-of-flight laser range finder (TOF-LRF) system with variations in atmospheric conditions, such as temperature, pressure, relative humidity, and the concentration of

Ambient index sensor using a Sagnac interferometer based on a D-shaped polarization maintaining fiber

CO_2

Fabrication of micro-ridge long-period gratings inscribed on polarization-maintaining fibers

. The measurement error of distance related with the group velocity change in the TOF-LRF system is analyzed by considering the refractive index of the standard atmosphere with variations in atmospheric conditions. The dependence of the pulse width broadening induced by chromatic dispersion of the standard atmosphere on the operating wavelength and the initial pulse width of the light sources is discussed. The transmission of air with variations in the relative humidity or the concentration of

The utilization and advantages of an exchange donor program in living donor renal transplantation: a single-center experience.

CO_2

Micro-ridge long-period fiber gratings inscribed on a polarization-maintaining fiber for measurement of strain

is analyzed by using different values of absorption coefficients depending on the operation wavelength of the light source in the TOF-LRF system.

A novel fabrication technique of corrugated long-period fiber gratings for mass production and its transmission characteristic as applied mechanical force

A Sagnac loop interferometer based on a hybrid polarization maintaining fiber (PMF) is proposed and experimentally demonstrated for measurement of ambient index. The hybrid PMF consists of the PMF and the locally D-shaped PMF. The important key component is the locally D-shaped PMF. Since the core mode of the locally D-shaped PMF is directly interfaced to the external environment, the core mode is immediately changed by the variation of external index. The birefringence of the locally D-shaped PMF can generate the interference patterns. Consequently, the flexibility and simplicity in the sensing scheme can be provided by the ambient index change can be measured simply and flexibly since the peak wavelength shift is only monitored by changing the ambient index. The sensitivity of ambient index was measured to be -30 nm/RIU.

Sensitivity of various D-shaped fibers to external refractive index change depending on coupling strength of evanescent field

We experimentally investigated a simple and new technique for the fabrication of micro-ridge long-period gratings (MRLPGs) based on polarization-maintaining fibers (PMFs). The cladding region of the PMFs was etched periodically using a wet etching technique resulting in the periodic formation of micro-ridges on the surface of the PMF. The PMF-based MRLPGs has two resonant peaks because of the birefringence of the PMF. The extinction ratios of two resonant peaks of the PMF-based MRLPGs were effectively improved by increasing the applied strain because of the photoelastic effect.

All-FBG-based switchable dual wavelength EDF laser with high tunability of lasing wavelength

INTRODUCTION The availability of donors is a major limiting factor in living donor renal transplantation. Approximately one third of patients with end-stage renal disease have willing potential living donors who are blood type or cross-match incompatible. The living donor kidney exchange has become an efficient solution for recipients in this situation. We analyzed the outcome and advantages of an exchange donor program compared with ABO-incompatible transplantation and desensitized protocol transplantation for highly sensitized patients. MATERIALS AND METHODS We retrospectively reviewed the medical records of 152 exchange donor cases from 1991 to 2010. We analyzed the risk factors, outcomes, matching factors, complication rates, and acute rejection rates of this program compared with other alternative strategies. RESULTS In our center, 22% of total living donor kidney transplantations were performed through an exchange program and an expanded donor pool. The graft survival, complication, and acute rejection rates were not significantly different compared with the alternatives. The severe complication rates were lower than with the alternatives and the immunosuppressant protocol and preoperative preparation were simpler. Blood type O recipients who registered in the exchange program showed no significant differences from the living related groups (P = .45), which were similar to the proportions for other ABO types. Upon multivariate analysis, an acute rejection episode and use of mycophenolate mofetil (MMF) were significant factors associated with graft survival (P = .015 and P = .007; odds ratio [OR] 5.968 and 7.324; 95% confidence interval [CI] .003-.533 and .098-.690). CONCLUSION Although exchange donor programs are not the sole solution, they show several advantages, such as the prescription of standard immunosuppression, simple preoperative preparation, low cost, and modest rates of severe complications compared with ABO-incompatible transplantation or desensitized protocols.