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Joseph C Liao

Publications and source records attributed to Joseph C Liao.

4 recordsLinked to original sources
PubMed2006

Incidence of ureteral strictures after laparoscopic donor nephrectomy.

PURPOSE: Previous reports of laparoscopic donor nephrectomy have suggested that preservation of the gonadal vein with the specimen is important for preventing ureteral strictures. To test this hypothesis we examined our series of patients for the incidence of ureteral strictures when the gonadal vein was not preserved with the specimen during laparoscopic donor nephrectomy. MATERIALS AND METHODS: We reviewed the records of 300 consecutive patients at our institution who underwent laparoscopic donor nephrectomy between 2000 and 2005. Mean donor age was 36.7 years (range 18 to 68) in the 167 female and 133 male donors. Mean recipient age was 38.4 years. Average followup was 2 years. During ureteral dissection the gonadal vein was transected just distal to the renal vein and left in situ. The ureter was dissected and transected at the level of the common iliac vessels. Indwelling ureteral stents were used for all recipient ureteral reimplantations and left in place for 1 month. In the postoperative period transplant recipients were followed biweekly for serum creatinine function during month 1 and monthly thereafter. All patients with increased creatinine (greater than 1.3 mg/dl) or an increasing trend were evaluated with transplant renal ultrasound. Clinically significant ureteral stricture was defined as persistent hydronephrosis resulting in impaired renal function and the need for percutaneous nephrostomy tube placement or ureteroscopic management. RESULTS: After laparoscopic living donor transplantation without gonadal vein preservation we found no incidence of clinically significant ureteral stricture. CONCLUSIONS: Gonadal vein preservation with the specimen during laparoscopic donor nephrectomy is not necessary. Preservation of the periureteral blood supply is sufficient to prevent ureteral strictures.

Adolescent↗
PubMed2006

Use of electrochemical DNA biosensors for rapid molecular identification of uropathogens in clinical urine specimens.

We describe the first species-specific detection of bacterial pathogens in human clinical fluid samples using a microfabricated electrochemical sensor array. Each of the 16 sensors in the array consisted of three single-layer gold electrodes-working, reference, and auxiliary. Each of the working electrodes contained one representative from a library of capture probes, each specific for a clinically relevant bacterial urinary pathogen. The library included probes for Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Enterocococcus spp., and the Klebsiella-Enterobacter group. A bacterial 16S rRNA target derived from single-step bacterial lysis was hybridized both to the biotin-modified capture probe on the sensor surface and to a second, fluorescein-modified detector probe. Detection of the target-probe hybrids was achieved through binding of a horseradish peroxidase (HRP)-conjugated anti-fluorescein antibody to the detector probe. Amperometric measurement of the catalyzed HRP reaction was obtained at a fixed potential of -200 mV between the working and reference electrodes. Species-specific detection of as few as 2,600 uropathogenic bacteria in culture, inoculated urine, and clinical urine samples was achieved within 45 min from the beginning of sample processing. In a feasibility study of this amperometric detection system using blinded clinical urine specimens, the sensor array had 100% sensitivity for direct detection of gram-negative bacteria without nucleic acid purification or amplification. Identification was demonstrated for 98% of gram-negative bacteria for which species-specific probes were available. When combined with a microfluidics-based sample preparation module, the integrated system could serve as a point-of-care device for rapid diagnosis of urinary tract infections.

Biosensing Techniques↗
PubMed2004

Rapid, species-specific detection of uropathogen 16S rDNA and rRNA at ambient temperature by dot-blot hybridization and an electrochemical sensor array.

Development of rapid molecular approaches for pathogen detection is key to improving treatment of infectious diseases. For this study, the kinetics and temperature-dependence of DNA probe hybridization to uropathogen species-specific sequences were examined. A set of oligonucleotide probes were designed based on variable regions of the 16S gene of the Escherichia coli, Proteus mirabilis, Klebsiella oxytoca, and Pseudomonas aeruginosa. A universal bacterial probe and probes-specific for gram-positive and gram-negative organisms were also included. The oligonucleotide probes discriminated among 16S genes derived from 11 different species of uropathogenic bacteria applied to nylon membranes in a dot-blot format. Significant binding of oligonucleotide probes to target DNA and removal of nonspecific binding by membrane washing could both be achieved rapidly, requiring as little as 10 min. An oligonucleotide probe from the same species-specific region of the E. coli 16S gene was used as a capture probe in a novel electrochemical 16-sensor array based on microfabrication technology. Sequence-specific hybridization of target uropathogen 16S rDNA was detected through horseradish peroxidase acting as an electrochemical transducer via a second, detector probe. The sensor array demonstrated rapid, species-specific hybridization in a time course consistent with the rapid kinetics of the dot-blot hybridization studies. As in the dot-blot hybridization studies, species-specific detection of bacterial nucleic acids using the sensor array approach was demonstrated both at 65 degrees C and at room temperature. These results demonstrate that molecular hybridization approaches can be adapted to rapid, room temperature conditions ideal for an electrochemical sensor array platform.

Bacteria↗