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Paulos Yohannes

Publications and source records attributed to Paulos Yohannes.

At least 19 recordsLinked to original sources
PubMed2005

Application of TZERO calibrated modulated temperature differential scanning calorimetry to characterize model protein formulations.

The objective of this study was to evaluate the feasibility of using T(ZERO) modulated temperature differential scanning calorimetry (MDSC) as a novel technique to characterize protein solutions using lysozyme as a model protein and IgG as a model monoclonal antibody. MDSC involves the application of modulated heating program, along with the standard heating program that enables the separation of overlapping thermal transitions. Although characterization of unfolding transitions for protein solutions requires the application of high sensitive DSC, separation of overlapping transitions like aggregation and other exothermic events may be possible only by use of MDSC. A newer T(ZERO) calibrated MDSC model from TA instruments that has improved sensitivity than previous models was used. MDSC analysis showed total, reversing and non-reversing heat flow signals. Total heat flow signals showed a combination of melting endotherms and overlapping exothermic events. Under the operating conditions used, the melting endotherms were seen in reversing heat flow signal while the exothermic events were seen in non-reversing heat flow signal. This enabled the separation of overlapping thermal transitions, improved data analysis and decreased baseline noise. MDSC was used here for characterization of lysozyme solutions, but its feasibility for characterizing therapeutic protein solutions needs further assessment.

Buffers↗
PubMed2004

Feasibility of robot-assisted totally intracorporeal laparoscopic ileal conduit urinary diversion: initial results of a single institutional pilot study.

OBJECTIVES: To explore the use of the da Vinci Surgical Robotic System (DSRS) to assist in the completion of totally intracorporeal laparoscopic ileal conduit urinary diversion (TLIC). METHODS: Two patients with radiation cystitis underwent TLIC procedures and another patient with bladder cancer underwent TLIC along with laparoscopic radical cystoprostatectomy at our institution. The ileal conduit urinary diversion was done totally intracorporeally using conventional laparoscopic techniques, and the DSRS was used to assist in the Bricker-type ureteroileal anastomosis. RESULTS: The 3 patients in the study included 2 men and 1 woman (mean age 73 years, range 64 to 84). The TLIC was completed intracorporeally in all 3 patients without the need for open conversion. The operative time, estimated blood loss, intraoperative decrease in hemoglobin, and time to hospital discharge for the 2 patients undergoing TLIC and the patient undergoing TLIC along with radical cystoprostatectomy was 628, 616, and 828 minutes, 50, 200, and 500 mL, 1.7, 2.8, and 5.3 g, and 5, 7, and 10 days, respectively. The median follow-up was 4.5 months (range 3.5 to 5.5). Postoperative satisfactory drainage of both kidneys was confirmed in all 3 patients at 8 weeks or later by intravenous urography or renal nuclear imaging. The serum creatinine remained stable in all 3 patients after surgery at hospital discharge. The only complication noted was postoperative ileus in the patient undergoing radical cystoprostatectomy that resolved with conservative management. CONCLUSIONS: TLIC is technically feasible and safe and can be done intracorporeally without complications. The DSRS can be successfully used to assist in the completion of TLIC. However, that each case lasted for more than 600 minutes highlights the need for further refinement in the technique. The practical application of TLIC requires improved long-term outcomes compared with open surgery, as well as a reduction in the operative time to justify the costs of robotic surgery.

Aged↗
PubMed2004

Laparoscopic nephron-sparing surgery in a Jehovah's Witness patient.

An obese 76-year-old woman with type II diabetes, hypertension, coronary artery disease, and gastroesophageal reflux was found to have a 6-cm lower-pole mass in a solitary functional right kidney. Because her religious beliefs prohibited blood transfusion, minimally invasive surgery--a laparoscopic partial nephrectomy--was performed, with a good result. Minimally invasive surgery, perhaps with administration of erythropoietin, iron-dextran, or both, is often a good option for severely anemic patients or those whose religious beliefs are opposed to transfusion. Methods of minimizing blood loss intraoperatively are reviewed.

Aged↗
PubMed2004

Retroperitoneoscopic nephrectomy v classic lumbotomy for pyonephrosis.

PURPOSE: To describe our experience and operative technique for retroperitoneoscopic nephrectomy for pyonephrosis and to compare the results with those of open surgery. PATIENTS AND METHODS: Since October 1998, 23 successful retroperitoneoscopic nephrectomies for pyonephrosis were performed in our institution (Group A). These patients were compared with 23 patients, matched by age, sex, and body weight, who underwent classic lumbotomy for pyonephrosis (Group B). The two groups were compared in terms of operative time, blood loss, hospital stay, wound complications, and time of return to previous occupation. RESULTS: All the features studied except operative time were significantly different in favor of laparoscopy. CONCLUSION: Although technically difficult, retroperitoneoscopic nephrectomy for pyonephrosis is feasible. The extraperitoneal approach allows direct access to the renal hilum and helps avoid spillage of pus into the peritoneum.

Adolescent↗
PubMed2004

Robot-assisted Bricker ileoureteral anastomosis during intracorporeal laparoscopic ileal conduit urinary diversion for prostatocutaneous fistula: case report.

BACKGROUND AND PURPOSE: The da Vinci robot is useful during minimally invasive surgery in performing intracorporeal suturing. We report one case of its application during laparoscopic ileal conduit urinary diversion for prostatocutaneous fistula. METHODS: A 58-year-old paraplegic man with a neurogenic bladder and bowel and a long history of urinary incontinence developed a prostatocutaneous fistula after numerous procedures to correct the incontinence. He underwent laparoscopic ileal conduit urinary diversion to improve his quality of life. The da Vinci robot was used to perform the ileoureteral anastomosis. RESULTS: The operative time was 10 hours. The estimated blood loss was <100 mL. There were no intraoperative complications. The patient was started on a clear liquid diet on postoperative day 3. There was no narcotic use because of the patient's neurologic status. The patient was discharged home on day 6. CONCLUSION: Laparoscopic urinary diversion remains a technically challenging procedure. The da Vinci robot is useful during laparoscopic ileal conduit construction.

Anastomosis, Surgical↗
PubMed2004

Primary adenocarcinoma of cutaneous vesicostomy 40 years later: a rare case.

We present a case of adenocarcinoma developing at the vesicocutaneous edge of a vesicostomy, 40 years after it was created, in a patient who underwent cadaveric kidney transplant. Although transitional and squamous cell carcinoma of a vesicostomy have been reported, to our knowledge, the presence of adenocarcinoma at the vesicostomy edge has not been reported previously.

Abnormalities, Multiple↗
PubMed2003

Rapid communication: laparoscopic Anderson-Hynes dismembered pyeloplasty using the da Vinci robot: technical considerations.

PURPOSE: To present our initial experience with laparoscopic pyeloplasty utilizing the da Vinci robot for upper tract reconstruction. CASE REPORT: A four-port transperitoneal approach was used in a 73-year-old man. The ureteropelvic (UPJ) obstruction was identified with a crossing vessel. After dismemberment of the UPJ, the renal pelvis was trimmed and reconstructed using the da Vinci robot. The total operative time was 5 hours; the time spent for reconstruction was 45 minutes. Blood loss was <150 mL. The postoperative analgesic requirement was 8 mg of morphine and 25 mg of hydrocodone. There were no intraoperative or postoperative complications. CONCLUSION: The da Vinci robot can serve as a vital surgical tool during pyeloplasty with extensive reconstruction.

Aged↗
PubMed2003

Laparoscopic radical excision of urachal sinus.

Persistent urachus is a rare congenital anomaly. Various types of remnants have been described including cyst, alternating sinus, patent urachus, diverticulum, and sinus. The most common presenting symptom of urachal sinus is umbilical discharge. Radical excision of the remnant, with or without a bladder cuff, is essential to prevent future malignant degeneration or recurrence of the remnant. Although open surgical excision has been the treatment of choice for many years, the laparoscopic approach has become an attractive alternative because of its association with less postoperative pain, better cosmesis, and rapid convalescence. Laparoscopic radical excision of a urachal sinus was performed in a 16-year-old female patient who presented with umbilical discharge.

Adolescent↗
PubMed2003

Laparoscopy-assisted robotic radical cystoprostatectomy with ileal conduit urinary diversion for muscle-invasive bladder cancer: initial two cases.

BACKGROUND AND PURPOSE: The use of the da Vinci robot is being investigated in the discipline of urologic surgery. We describe our experience with its use during radical cystoprostatectomy in two patients with organ-confined bladder cancer. PATIENTS AND METHODS: Laparoscopic radical cystoprostatectomy with ileal conduit urinary diversion was performed using the da Vinci robot. Both patients were informed about this new approach, and informed consent was obtained. RESULTS: There were no intraoperative or postoperative complications. The operative time was 10 and 12 hours. A clear liquid diet was started on the third postoperative day. Final histopathology examination in both patients revealed T(3a)N(0)M(0) transitional-cell carcinoma. The hospital stay was 6 days. Both patients returned to normal activity within 2 weeks. CONCLUSION: Robot-assisted laparoscopic radical cystoprostatectomy with ileal conduit urinary diversion for muscle-invasive bladder cancer is feasible.

Humans↗
PubMed2003

Rapid communication: pure robot-assisted laparoscopic ureteral reimplantation for ureteral stricture disease: case report.

BACKGROUND AND PURPOSE: The role of the da Vinci robot is slowly being defined in minimally invasive urologic surgery. We report its use in the management of ureteral stricture disease. CASE REPORT: A 42-year-old man with recurrent kidney stone disease was found to have a left distal-ureteral stricture. After failure of endoscopic treatment, a robot-assisted laparoscopic ureteral reimplantation was performed. The total operative time was 210 minutes. The estimated blood loss was <50 mL. There were no intraoperative or postoperative complications. Total analgesic use was 30 mg of morphine. The hospital stay was 5 days. CONCLUSION: Pure robot-assisted laparoscopic ureteral reimplantation is a safe and feasible approach to the management of ureteral stricture disease.

Adult↗
PubMed2003

Ureteral endometriosis.

PURPOSE: This review discusses the pathophysiology, presentation, and different minimally invasive medical and surgical treatment options for ureteral endometriosis. MATERIALS AND METHODS: A comprehensive literature review of reports on the diagnosis and management of ureteral endometriosis was performed using MEDLINE. RESULTS: Ureteral endometriosis is a rare disease. Most cases present with silent obstruction, as opposed to cyclical hematuria. The diagnosis of ureteral endometriosis requires a high index of suspicion. A variety of diagnostic tests can help identify the extent of disease and the degree of renal function on the side of ureteral involvement. CONCLUSIONS: Ureteral endometriosis can be treated with hormones or surgical intervention. While surgery is reserved for hormone refractory cases and obstruction associated with extensive scarring, the majority of cases can be managed with hormones only. A combination of hormones and surgery is also effective. Surveillance for obstructive uropathy with periodic noninvasive monitoring of kidney function is currently recommended for all patients with endometriosis.

Danazol↗
PubMed2002

Tail stent versus re-entry tube: a randomized comparison after percutaneous stone extraction.

OBJECTIVES: To evaluate the efficacy of a 7F tail stent with an 18F Councill nephrostomy tube and compare it to a 24F re-entry Malecot nephrostomy tube after percutaneous nephrolithotomy. METHODS: Forty patients were prospectively randomized to receive either a 24F re-entry Malecot nephrostomy tube (group A, n = 20) or a 7F tail stent with an 18F Councill nephrostomy tube (group B, n = 20) for postoperative drainage. Patients were evaluated with an analogue scale questionnaire 15 days after percutaneous nephrolithotomy at the routine office follow-up visit asking them to rate the flank pain on a 0 to 10 scale, urinary urgency on a 0 to 10 scale, and quality of life, while the external drainage tubes were still in place. RESULTS: The mean length of stay was 4.5 and 3.5 days for groups A and B, respectively. Flank urine leakage was present in all patients in group A for a period of 6 to 12 hours, and no patient in group B had any significant flank drainage. A statistically significant reduction of flank pain in favor of group B was observed (P = 0.0002). We did not observe any statistically significant difference when evaluating the urgency (P = 0.1) and quality-of-life scores (P = 0.09) between the two groups, even though a trend was noted toward amelioration in favor of group B patients. CONCLUSIONS: The results of the present study suggest that the 7F tail stent is certainly better tolerated by the patients after percutaneous nephrolithotomy compared with the standard 24F re-entry Malecot nephrostomy tube.

Drainage↗
PubMed2002

Urinary retention during the second trimester of pregnancy: a rare cause.

Acute urinary retention during pregnancy is rare. Retention secondary to an impacted, gravid uterus is an emergency. Retroversion of the uterus, a history of pelvic inflammatory disease, and large fibroids are predisposing factors. The enlarging gravid uterus and uterine fibroids may trap the uterus inside the pelvic ring, preventing it from ascending into the abdominal cavity; furthermore, a history of inflammatory disease may trap the fundus of the uterus within scar tissue that also may prevent the enlarging, gravid uterus from ascending into the abdominal cavity. The impacted uterus should be manually replaced in the anterior position. Clean intermittent catheterization and placement of a vaginal pessary are temporizing measures. A knowledge of the causes of urinary retention during pregnancy can help prevent spontaneous abortion and other devastating consequences that can arise as a result of a delay in the diagnosis.

Acute Disease↗
PubMed2002

Comparison of robotic versus laparoscopic skills: is there a difference in the learning curve?

OBJECTIVES: To evaluate the learning curve between robot-assisted and manual laparoscopic suturing, as well as to assess other skills. Laparoscopic reconstructive procedures have been limited by instrumentation, small working spaces, and fixed angles at the trocar level to place sutures. Robot-assisted laparoscopic suture placement may provide one means of increasing dexterity and facilitating laparoscopic reconstructive procedures. METHODS: Eight physicians participated in this study. A series of five trials were performed to assess dexterity (task 1) and free-hand suturing (task 2). Each task was performed using robot-assisted and manual laparoscopy. The participants were categorized as novice and experienced laparoscopists. Task 1 involved passing sutures through the eye of seven needles positioned 1 cm apart in a P configuration. Task 2 involved tying one surgeon's knot, followed by two subsequent knots. RESULTS: The average time for trials 1 and 5 of task 1, robot-assisted laparoscopy, was 242.6 and 101.8 seconds, respectively (P <0.001). Both groups demonstrated a statistically significant difference (P <0.001) between the first and last trial. The average time for trials 1 and 5 of task 1, manual laparoscopy, was 205.3 and 169 seconds, respectively. The differences in the learning curves for robot-assisted and manual laparoscopy were statistically significant in favor of robotic assistance. Manual laparoscopic suturing did not demonstrate as much of a difference for the experienced surgeon. Overall, the difference in improvement between robot-assisted and manual laparoscopy was not statistically significant. CONCLUSIONS: Robot-assisted laparoscopic allows suturing and dexterity skills to be performed quicker than does manual laparoscopy.

Clinical Competence↗
PubMed2002

Role of acellular collagen matrix surgisis in the endoscopic management of ureteropelvic junction obstruction.

PURPOSE: To investigate the role of acellular collagen matrix (Surgisis during endopyelotomy. MATERIALS AND METHODS: Nine female pigs (25-35 kg) were enrolled in our protocol. The pigs were categorized as follows. Group I (N = 3) had endopyelotomy + insertion of SIS, Group II (N = 3) creation of UPJ stricture + endopyelotomy + insertion of SIS, and Group III (N = 3) Davis intubated ureterotomy using SIS. The contralateral side served as a control for each group (one pig in each group). In three pigs (two in Group III and one in Group II), Surgisis was treated with India ink prior to insertion at the endopyelotomy site. An endopyelotomy stent (14/8 F x 24 cm) was used to stent the ureteropelvic junction (UPJ) for 4 weeks. Four weeks after the stent was removed, laparoscopic nephroureterectomy was performed, and the animals were euthanized. Histopathologic analysis of the Surgisis-regenerated segment of the UPJ was performed using hematoxylin and eosin, reticular (collagen), smooth muscle actin, and S-100 (nerve) stains. RESULTS: All animals tolerated the procedure. The mean operative time was 162 minutes. One pig (Group II) developed pyonephrosis; one pig (Group III) developed significant ascites and was sacrificed 2 week before the end of the experiment. Histopathologic analysis showed complete epithelializaton at 8 weeks. Reticular stain demonstrated abundant collagen matrix in the submucosa. Smooth muscle staining revealed myofibroblastic proliferation within the SIS-regenerated tissue adjacent to disorganized smooth muscle cells. India ink-stained SIS-regenerated tissue did not show smooth muscle cells. The S-100 stain did not demonstrate neurons at 8 weeks; however, in three pigs, peristaltic activity was noted across the UPJ. CONCLUSION: The use of acellular collagen matrix in the endoscopic management of UPJ obstruction is a promising technique. The abundance of myofibroblasts and absence of abundant smooth muscle regeneration indicates a need to investigate the role of growth factors in SIS regeneration of host tissue.

Actins↗
PubMed2002

Reconstruction of rabbit urethra with surgisis small intestinal submucosa.

PURPOSE: To evaluate the efficacy of Surgisis, porcine small intestinal submucosa, in the reconstruction of iatrogenic urethral defects in rabbits. MATERIALS AND METHODS: Eight male white rabbits were enrolled in this protocol. A 2.5-cm segment of urethra was excised. One control consisted of a normal urethra. The other rabbits underwent urethroplasty with Surgisis and 6-0 Vicryl running suture. An 8F feeding tube was left in place to divert urine for 2 weeks after surgery. Retrograde urethrograms were performed to assess the patency of the urethras and to rule out fistula formation prior to sacrifice of the animals. The sacrifice protocol began with the control and a urethroplasty animal 6 weeks after surgery. The other rabbits were euthanized at 2-week intervals thereafter. RESULTS: Surgisis promoted epithelial regeneration in all cases. One animal developed a wound infection; this was associated with a small fistula at the proximal end of the anastomosis. Good cosmetic and functional results were documented. Retrograde urethrograms showed no stricture formation at the site of the anastomosis in six rabbits. The histopathologic examination showed complete regeneration of all urethral layers, almost indistinguishable from the normal urethra. CONCLUSION: Surgisis is an excellent material for urethral reconstruction in rabbits. It promotes regeneration of all the components of the host urethral layers and is biodegradable.

Animals↗
PubMed2002

Endoscopic management of renal lymphangioma: a case report.

A 46-year-old woman presented with total painless gross hematuria, an 8-mm polypoid mass that proved to be a lymphangioma was found in the upper pole collecting system of the left kidney. The mass was resected ureteroscopically with holmium laser fulguration of the base. The few reported cases of this rare lesion suggest that rigorous postoperative surveillance is not necessary for this benign condition.

Female↗