Biomedical subjects

R L Kuo

Publications and source records attributed to R L Kuo.

14 recordsLinked to original sources

PubMed2001

An indicator cell assay for detection of human cytomegalovirus based on enhanced green fluorescent protein.

An indicator cell line (ML-UL54-EGFP) for the detection of human cytomegalovirus (HCMV) by a simple and direct method was developed. The stable line was constructed by introducing into mink lung cells an expression cassette that contains the enhanced green fluorescent protein (EGFP) reporter gene under the control of an HCMV-inducible promoter. The promoter was from the upstream region of the HCMV UL54 (pol) gene, an early gene promoter that is activated in the early phase of HCMV infection. Following infection with HCMV for 48 h, the stable line expressed well detectable level of the EGFP as observed under a fluorescence microscope. The sensitivity of the indicator cell assay is at least comparable with that of a plaque assay as assessed with a panel of HCMV strains. There were no detectable fluorescent cells after inoculations with several viruses other than HCMV, indicating high specificity. Analysis with flow cytometry revealed that the induced fluorescence from the infected cells was proportional to the titer of HCMV inoculated, making it possible to quantify HCMV infectious particles. In summary, the EGFP-based indicator cell line is of potential use for rapid detection and quantification of HCMV in clinical specimens.

Animals↗

PubMed2001

Current urologic applications of digital imaging.

One of the most significant developments in imaging technology has been the process of digitalization. By incorporating currently available digital imaging equipment into surgical practice, urologists can be assured of obtaining real-time video images with optimal clarity and detail. In addition, one can efficiently capture and store still images that are crisper and sharper than their analog counterparts. These factors greatly improve the diagnostic capabilities and organization of today's endourologist.

Diagnostic Techniques, Urological↗

PubMed2001

Telemedicine: recent developments and future applications.

Telemedicine, or the delivery of health care from a distance, is an exciting field that has undergone rapid advancements over the past three decades. Previous studies have demonstrated that telemedicine can effectively assist in patient care. However, cost issues and the lack of resources to sustain telemedicine systems have previously limited the use of this technology. Herein, we explore the development, current applications, and future of telemedicine.

Analog-Digital Conversion↗

PubMed2001

Virtual reality: current urologic applications and future developments.

The concept of virtual reality (VR) involves the computer generation of environments with which a user can interact directly. Virtual reality is now being used for medical applications, especially in the area of surgical simulation. As technology advances, VR simulation will play an important training role for both residents and urologists already in practice. This paper examines the history of VR, current developments, and its future implications for the field of urology.

Computer Simulation↗

PubMed2000

Microdialysis assessment of shock wave lithotripsy-induced renal injury.

OBJECTIVES: Shock wave lithotripsy (SWL) is the primary treatment modality for managing the majority of symptomatic renal calculi. However, the fundamental mechanisms for stone fragmentation and the resultant morphologic changes that occur are not fully understood. Furthermore, a thorough understanding of the complex biologic pathways involved in SWL-induced renal injury does not exist at present. To elucidate the biologic processes involved in tissue injury after SWL, an animal model was designed to mimic the pathogenesis of high-energy SWL in humans. METHODS: Juvenile female swine were anesthetized, and a midline laparotomy incision was performed to expose the right kidney. Using an introducer apparatus, a microdialysis probe was placed into the renal parenchyma of the right kidney lower pole and a tunnel was generated to exit the distal ends of the inlet and outlet tubing outside the body. After a 72-hour postoperative recovery period, SWL was performed to the lower pole renal region of the kidney, as a microdialysis pump continuously infused dialysate through the inlet tubing. Microdialysis fluids were collected during SWL, and lipid peroxidation, as measured by conjugated diene concentrations, was monitored. RESULTS: All microdialysis probes remained patent for a total of 2000 shock waves. A significant elevation in conjugated diene levels was observed in the SWL versus untreated kidneys after 1000 shock waves were administered (P <0.02). CONCLUSIONS: This animal model is unique in that it represents the first system for the real-time collection of renal interstitial fluids during SWL. Analysis of this fluid may provide insight into the physiologic mechanisms responsible for shock wave-induced renal injury.

Animals↗

PubMed2000

Rapid diagnosis and quantification of herpes simplex virus with a green fluorescent protein reporter system.

A genetically modified cell line (Vero-ICP10-EGFP) was constructed for detection of herpes simplex virus (HSV) by a simple, rapid and direct method. The cell line was developed by stable transfection of Vero cell with a plasmid encoding the green fluorescent protein (GFP) driven by the promoter of the HSV-2 ICP10 gene. As early as 6 h after infection with HSV, fluorescence-emitting cells can be observed under a fluorescence microscope. A single infected cell emitting fluorescence can be observed with soft agar overlay by inverted fluorescence microscopy. No induction of detectable fluorescence was seen following infections with human cytomegalovirus (HCMV), varicella zoster virus (VZV), coxsackievirus A16 and enterovirus 71. Analysis by flow cytometry also demonstrated that intensity of the triggered fluorescence is proportional to the titer of HSV inoculated. Taken together, this novel GFP reporter system could become a useful means for rapid detection and quantification of HSV in clinical specimens.

Animals↗

PubMed2000

Combined antegrade and retrograde endoscopic approach for the management of urinary diversion-associated pathology.

BACKGROUND: Endourologic management of stones and strictures in patients with a urinary diversion is often cumbersome because of the absence of standard anatomic landmarks. We report on our technique of minimally invasive management of urinary diversion-associated pathology by means of a combined antegrade and retrograde approach. PATIENTS AND METHODS: Five patients with urinary diversion-associated pathology were treated at our institution between May 1997 and October 1998. Their problems were: an obstructing ureteral stone in a man with ureterosigmoidostomy performed for bladder extrophy; two men with a valve stricture in their hemiKock urinary diversions; an anastomotic stricture in a man with an ileal loop diversion; and a long left ureteroenteric stricture in a man with a right colon pouch diversion. After percutaneous placement of an guidewire across the area of interest, the targeted pathology was accessed via a retrograde approach using standard semirigid or flexible fiberoptic endoscopes. Postoperative follow-up with intravenous urography, differential renal scan, or both was performed at 3 to 24 months (mean 12 months). RESULTS: The combined antegrade and retrograde approach allowed successful access to pathologic areas in all patients. Holmium laser/Acucise incision of stenotic segments or ballistic fragmentation of stones was achieved in all cases without perioperative complications. None of the strictures with an initially successful outcome has recurred; however, in one patient, the procedure failed as soon as the internal stent was removed. The patient with the ureteral calculus remains stone free, and his ureterosigmoidostomy is patent without evidence of obstruction on his last imaging study, 24 months postoperatively. CONCLUSIONS: Combined antegrade and retrograde endoscopic access to the area of interest is our preferred method of approaching pathologic problems in patients with a urinary diversion. An antegrade nephrostogram provides better delineation of anatomy, while through-and-through access enables rapid and easier identification of stenotic segments that may be hidden by mucosal folds. Furthermore, this approach allows the use of larger semirigid or flexible endoscopes in conjunction with more efficient fragmentation devices, resulting in enhanced vision from better irrigation. Finally, an initial endoscopic approach may be preferred because its failure does not compromise the success of future open surgery.

Aged↗

PubMed2000

Clinical efficacy of combined lithoclast and lithovac stone removal during ureteroscopy.

PURPOSE: Pneumatic lithotripsy has proved to be an extremely safe, efficient and low cost intracorporeal fragmentation modality. Unfortunately proximal migration of fragments into inaccessible areas in the intrarenal collecting system is a potential limitation during ureteroscopic procedures. Moreover, the lack of an efficient mechanism of stone retrieval further limits the widespread application of this technique. The newly developed Lithovacdagger suction device was designed to be combined with pneumatic lithotripsy during ureteroscopic stone removal. We evaluated the effectiveness of this combination for overcoming these limitations. MATERIALS AND METHODS: Between February and December 1998, 21 patients underwent pneumatic lithotripsy of ureteral calculi combined with use of the Lithovac suction probe. Stone area was 20 to 320 mm.2 (mean 84). Of the stones 71% and 29% were in the distal, and proximal and/or mid ureter, respectively. We used a 0.8 mm. pneumatic lithotripsy probe placed through a 4.8Fr Lithovac probe at a pulse frequency of 12 Hz. and pressure of 2 atmospheres. RESULTS: Mean operative time was 42 minutes and the stone fragmentation rate was 100%. There were no complications in our series and no proximal migration of fragments. The overall stone-free rate was 95% at 3-month followup. CONCLUSIONS: Using the Lithovac suction device greatly facilitates pneumatic lithotripsy during ureteroscopic stone removal. This combination not only prevents fragment migration, but also aids in maintaining a clear endoscopic field of view, allowing efficient, safe and effective stone fragmentation.

Adolescent↗

PubMed1999

Incorporation of patient preferences in the treatment of upper urinary tract calculi: a decision analytical view.

PURPOSE: Patient preferences, or utilities, may be crucial to select an appropriate treatment plan for stone disease. We used decision modeling to understand better patient choices and decision making in the overall management of recurrent nephrolithiasis. MATERIALS AND METHODS: We interviewed 180 consecutive patients with active stone disease. Demographic data and historical experiences with calculi were recorded. Patients were presented with 6 hypothetical clinical scenarios and various treatment options. The standard gamble method was used to obtain utility values for each option. RESULTS: Nephrectomy had the lowest mean utility value of 0.883. Percutaneous nephrolithotomy for severe, moderate and mild pain had utilities of 0.924, 0.932 and 0.947, respectively. Shock wave lithotripsy for the management of mild pain was the most attractive option (mean utility 0.968). The utility for long-term medical therapy was 0.949, which was between that of percutaneous nephrolithotomy and shock wave lithotripsy for mild pain. Patients with a surgical history of stone removal assigned lower utilities to invasive procedures (nephrectomy, percutaneous nephrolithotomy, p <0.05). As the incidence of spontaneous stone passage increased, a higher utility was given to long-term medical therapy (p <0.05). Patients on medical therapy less than 1 year did not appreciate a significant benefit of medical prophylaxis. However, longer compliance with medical management led patients to perceive increasing benefits of continuing such medical treatment (p <0.05). Patients who had undergone stone removal via endoscopic or open surgery also had a higher preference for medical therapy (p <0.05). CONCLUSIONS: Patients who had undergone stone removal wanted to avoid future invasive procedures. They ranked long-term medical therapy below shock wave lithotripsy but above invasive procedures, such as percutaneous nephrolithotomy. Most importantly, patients appreciated the benefits of medical therapy the longer that they complied with specific recommendations. These results support the concept that patients perceive long-term medical therapy to prevent recurrent nephrolithiasis as a desirable treatment option.

Adolescent↗

PubMed1999

Use of a digital camera in the urologic setting.

Urologists are faced with increasing demands for clear documentation of their work. We report the use of a digital camera in our practice to capture images throughout the urologic setting. The digital camera was a quick and convenient means of obtaining good quality reproductions of radiographic and pathologic findings. Use of the camera greatly enhanced the efficiency of our practice by allowing incorporation of images into patient records and an image library.

Humans↗

PubMed1999

Secure transmission of urologic images and records over the Internet.

PURPOSE: Telemedicine has become a common method for the transmission of images and patient data across long distances. Our goal was to assess the efficiency and accuracy of Photomailer MD software, a store-and-forward telemedicine system, in the urologic setting. METHODS: Photomailer MD software was loaded on two computers in the host institution, one with a T1 connection to the Internet and the other with a dial-up modem connection (24,000 bits/second), and computers at three remote sites. A total of 14 clinical cases, comprised of digitized histories and radiographic images, were sent to the remote institutions four separate times using the four transmission modes available: nonencrypted, 56-bit encryption, 128-bit encryption, and 128-bit encryption with password. The following data points were recorded: file size before and after encryption, file transmission times, and diagnostic accuracy of the remote urologists. One-way ANOVA was used to compare mean values statistically, while the z-test was used to compare diagnostic accuracies. RESULTS: Encryption increased the file size by a mean of 37.8%, with the three encryption modes increasing file sizes by the same number of kilobytes. When a dial-up modem was used, encrypted files required a significantly longer transmission time (P < 0.05) than the unencrypted files. The same trend was seen with the T1 connection, although the differences often were not significant. When T1 transmission times were compared with modem times with other variables held constant, modem times were significantly longer (P < 0.05). Diagnostic accuracies for each of the three remote centers ranged from 85.7% to 100%. Differences in accuracy rates between attending physicians and residents were not significant. CONCLUSIONS: Photomailer MD provides a secure, convenient, and affordable method of transmitting patient images and records via the Internet. Transmission speed was significantly greater when using a T1 line and also tended to be faster when files were not encrypted. There was no significant difference in transmission time among the three encryption modes; therefore, 128-bit encryption with a password should be used to maximize security. Diagnostic accuracies were comparable to those in the literature. In general, 640 x 480-pixel resolution was adequate for urologic diagnoses, although higher-resolution images may improve accuracy.

Analysis of Variance↗

PubMed1999

Advances in digital imaging during endoscopic surgery.

BACKGROUND AND OBJECTIVE: Digital imaging capabilities have recently been incorporated into a number of video systems. Contrast enhancement when using a rigid or semirigid endoscope improves image definition by seeking out existing transitions in detail. Only the areas of transition are accentuated, whereas areas without detail are unaffected. During flexible endoscopy, fiberoptic bundles create a classic honeycomb appearance. The use of "fiberscope" filters minimizes this appearance by expanding the image of each fiberoptic fiber. We therefore assessed whether new developments in digital video image processing have improved image quality for endoscopic surgery. MATERIALS AND METHODS: Fifty urologists reviewed a video playback of various endourologic procedures. The type of endoscope was identified, but the urologic surgeon was blinded to the level of enhancement (high or low) or fiberscope filter (A or B) used. Each video clip was scored from 1 to 5 for the following image variables: identification of structure, detail of image, and background noise or interference. All results were averaged and compared using Student's paired t-test. RESULTS: During rigid endoscopy, the high and low digital enhancement settings were both superior to no enhancement (P < 0.001), and high enhancement was better than low (P < 0.001). With semirigid endoscopic procedures, high and low digital enhancement were comparable but were superior to no enhancement (P < 0.001). Filters A and B were no better than no enhancement. There was a significant improvement noted with the use of filter A or B during flexible ureteroscopy over no enhancement (P < 0.001). In addition, filter A was better than filter B (P < 0.001). CONCLUSIONS: Digital enhancement settings during video endoscopy significantly improve images from rigid and semirigid endoscopes. The digital fiberscope filter significantly improves images obtained during flexible ureteroscopy. Digital image enhancement capabilities should be strongly considered when upgrading video systems. Digital technology must be further studied to improve clinical video imaging during endoscopic surgery.

Endoscopy↗

PubMed1998

Use of ureteroscopy and holmium:YAG laser in patients with bleeding diatheses.

OBJECTIVES: To assess the safety and efficacy of ureteroscopy and holmium laser in patients with known bleeding diatheses and upper tract calculi or transitional cell carcinoma (TCC). METHODS: Eight patients with stone disease and 1 patient with upper tract TCC were treated ureteroscopically with the holmium laser. The mean age was 58.3 years (range 42 to 74). Six patients were receiving Coumadin, with a mean international normalized ratio (INR) of 2.1 (normal INR less than 1.1). Two patients were thrombocytopenic, and 1 had von Willebrand's disease. None of the bleeding diatheses were corrected before surgery. Semirigid or flexible ureteroscopes were used to access the ureter or intrarenal collecting system. The holmium laser was used to fragment calculi or ablate tumor. RESULTS: Only 1 patient had a postoperative bleeding complication related to the procedure, involving an episode of oliguria secondary to a small ureteral clot. This cleared without surgical intervention. Another patient developed an episode of epistaxis after administration of ketorolac for pain. Six of 7 patients who underwent laser fragmentation for calculi were stone free on follow-up intravenous urogram at 1 month, and no tumor recurrence was noted in the patient with TCC (follow-up of 4 months). CONCLUSIONS: Ureteroscopy allowed excellent access to all regions of the upper tracts, and holmium laser fragmentation of calculi or ablation of tumor was effective in managing each particular problem. Use of the holmium laser with ureteroscopic access provides a safe and acceptable combination for treating upper tract pathology in patients with uncorrected bleeding diatheses. As a result, these patients can avoid added costs of extended hospital stay and risks associated with transfusions.

Adult↗

PubMed1998

Impact of holmium laser settings and fiber diameter on stone fragmentation and endoscope deflection.

We compared the impact of various energy settings, frequency, and fiber diameters on the stone fragmentation capabilities of the holmium laser. Stone phantoms, made from plaster of Paris and uniform in weight, were treated with one of two laser fiber sizes: small (200 and 365 microm) and large (550 and 1000 microm). Stones were immersed in water and fragmented for 3 minutes at 0.5, 1.0, or 2.0 J and 5, 10, or 15 Hz. The mean percentage decrease in weight in the two groups was compared using one-way ANOVA. The effect on flexible ureterorenoscope deflection of the small fibers was tested in two different ureterorenoscopes. Raising the energy level when using the small fibers resulted in more weight loss (P < 0.05). Increasing the frequency up to 10 Hz also resulted in a significant increase in weight loss (P < 0.05), yet above 10 Hz, there was no significant additional weight loss noted for either small fiber. There was no significant difference in the weight loss produced by the two fibers unless the energy setting was >1.0 J. Studies with the large fibers demonstrated similar results, with significant increments of weight loss occurring with increased energy (P < 0.05), while nonsignificant differences were seen for the two fiber diameters. Increasing laser frequency up to 15 Hz resulted in a significant increase in weight loss for the large fibers. Loss of ureterorenoscope deflection ranged from 7% to 16% and 18% to 37% for the 200-microm and 365-microm fibers, respectively. Small-diameter fibers, in combination with semirigid or flexible ureteroscopes, should be used to treat upper urinary tract stones. The 365-microm fiber should be utilized for the management of ureteral stones, as minimal endoscopic deflection is required to access these calculi. Because the 200-microm fibers are considerably more expensive, their use should be reserved for fragmentation of intrarenal calculi, where maximum deflection is required during flexible ureterorenoscopy. The ideal energy and frequency settings for the small fibers are <1.0 J and 5 to 10 Hz. Larger fibers can be used for managing bladder or renal calculi, as there is no need for significant fiber deflection. The 550-microm fiber is preferred, as it is comparable in efficacy to the 1000-microm fiber and is less expensive. Energy and frequency can be maximized to 2.0 J and 15 Hz without damage to the fiber, but visibility can be affected by high frequencies. Appropriate fiber selection and energy/frequency settings will allow access to most stones throughout the urinary tract, maximize fiber life, and minimize fiber expense.

Analysis of Variance↗