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Biomedical subjects

R G Moore

Publications and source records attributed to R G Moore.

At least 19 recordsLinked to original sources
PubMed2006

Dopant-induced nanoscale electronic inhomogeneities in Ca(2-x)Sr(x)RuO4.

Ca(2-x)Sr(x)RuO4 single crystals with 0.1 < or = x < or = 2.0 have been studied systematically using scanning tunneling microscopy (STM) and spectroscopy, low-energy electron diffraction, and angle resolved photoelectron spectroscopy (ARPES). In contrast with the well-ordered lattice structure, the local density of states at the surface clearly shows a strong doping dependent nanoscale electronic inhomogeneity, regardless of the fact of isovalent substitution. Remarkably, the surface electronic roughness measured by STM and the inverse spectral weight of quasiparticle states determined by ARPES are found to vary with x in the same manner as the bulk in-plane residual resistivity, following the Nordheim rule. For the first time, the surface measurements--especially those with STM--are shown to be in good agreement with the bulk transport results, all clearly indicating a doping-induced electronic disorder in the system.

Journal Article↗
PubMed2001

How does cognitive therapy prevent relapse in residual depression? Evidence from a controlled trial.

This study examined the cognitive mediation of relapse prevention by cognitive therapy (CT) in a trial of 158 patients with residual depression. Scores based on agreement with item content of 5 questionnaires of depression-related cognition provided no evidence for cognitive mediation. A measure of the form of response to those questionnaires, the number of times patients used extreme response categories ("totally agree" and "totally disagree"), showed significant and substantial prediction of relapse, differential response to CT. and conformity to mediational criteria. CT reduced relapse through reductions in absolutist, dichotomous thinking style. CT may prevent relapse by training patients to change the way that they process depression-related material rather than by changing belief in depressive thought content.

Adult↗
PubMed2001

Comparison and analysis of laparoscopic intracorporeal suturing devices: preliminary results.

BACKGROUND AND PURPOSE: One of the most challenging aspects of laparoscopic surgery is intracorporeal suturing and knot tying. A loss of depth perception and tactile sense and visual obstruction make placing accurate and well-tied knots a difficult and time-consuming task. Two devices conceived to ease the task of suturing and knotting while presumably speeding performance are the Suture Assist (SA; Ethicon Endo-Surgery) and EndoStitch (ES; US Surgical/Tyco). We set out to objectively assess suture placement accuracy and knot speed and strength of these two suturing devices and conventional laparoscopic suturing (CS). MATERIALS AND METHODS: To date, six surgeons with laparoscopic experience were trained on the three suturing techniques. A pelvic trainer was set up with a freshly marked and incised swine renal pelvis and ureter. Each surgeon placed four sutures of 2-0 polyester suture with each technique (repeated on three separate occasions) with five half-hitches for a total of 216 knots. Time, strength, and accuracy were measured for each suture/knot placement. The knot distance was then measured from the marked target using calipers and carefully dissected from the tissue. Each knot was individually tested on a Monsanto Model 10 tensiometer, whereby slippage, strength, and breakage points were determined. RESULTS: The mean times (min:sec) and accuracy (millimeters) were as following: CS 5:08 and 0.457, ES 2:45 and 0.660, and SA 2:40 and 0.508. The difference in time was found to be statistically significant (P < 0.001), while the difference in accuracy was not. Only 182 of 216 knots were able to be included for analysis because of either a small knot lumen or device failure. Device failures necessitating intervention were encountered only with the SA, which had a misfire rate of 9.7% (7 of 72). The mean knot strength was measured at 41.1 N for CS, 57.3 N for SA, and 28.0 for ES. Knot break percentage (breakage) was calculated as 50.8% for CS, 20.7% for ES, and 95% for SA. CONCLUSION: Preliminary results show that each of the laparoscopic suturing devices has distinct advantages over conventional intracorporeal suturing and tying. Decreased times and comparable, if not greater, knot strengths may translate into improved laparoscopic suturing/tying performance for laparoscopic intracorporeal suturing devices.

Equipment Design↗
PubMed2000

Survey of neuromuscular injuries to the patient and surgeon during urologic laparoscopic surgery.

OBJECTIVES: Laparoscopy may be complicated by neuromuscular injuries, both to the patient and to the surgeon. We used a survey to estimate the incidence of these injuries during urologic laparoscopic surgery, to assess risk factors for these injuries, and to determine preventive measures. METHODS: A survey of neuromuscular injuries associated with laparoscopy submitted to 18 institutions in the United States was completed by 18 attending urologists from 15 institutions. RESULTS: From among a total of 1651 procedures, there were 46 neuromuscular injuries in 45 patients (2.7%), including abdominal wall neuralgia (14), extremity sensory deficit (12), extremity motor deficit (8), clinical rhabdomyolysis (6), shoulder contusion (4), and back spasm (2). Neuromuscular injuries were twice as common with upper retroperitoneal as with pelvic laparoscopy (3. 1% versus 1.5%). Among patients with neuromuscular injuries, those with rhabdomyolysis were heavier (means 91 versus 80 kg) and underwent longer procedures (means 379 versus 300 minutes), and those with motor deficits were older (means 51 versus 42 years of age). Of the surgeons, 28% and 17% reported frequent neck and shoulder pain, respectively. CONCLUSIONS: Although not common, neuromuscular injuries during laparoscopy do contribute to morbidity. Abdominal wall neuralgias, injuries to peripheral nerves, and joint or back injuries likely occur no more frequently than during open surgery, but risk of rhabdomyolysis may be increased. Positioning in a partial rather than full flank position may reduce the incidence of some injuries. Measures to reduce neuromuscular strain on the surgeon during laparoscopy should be considered.

Abdominal Muscles↗
PubMed2000

Laparoscopic pyeloplasty.

Open pyeloplasty has long been considered the gold standard for the relief of ureteropelvic junction (UPJ) obstruction, but the incisional morbidity led urologists to explore less invasive alternatives such as endopyelotomy and the Acucise cutting balloon. Laparoscopic pyeloplasty was introduced in 1993 and has since been performed in patients as young as 2.5 years. The operation should be considered in patients with UPJ obstruction caused by a crossing vessel, high ureteral insertion, failed prior procedures, high-grade hydronephrosis, or marginal differential renal function. Hynes-Anderson, Foley Y-V, and Fenger procedures can all be performed laparoscopically, generally with excellent results. The procedure requires advanced laparoscopic skills and so is available in only a few medical centers at present.

Child↗
PubMed1999

Measurement of urinary N-acetyl-beta-D-glucosaminidase to assess renal ischemia during laparoscopic operations.

BACKGROUND: Oliguria during laparoscopy is a well-documented phenomenon of unknown etiology. Experimental evidence suggests that renal perfusion is reduced during pneumoperitoneum. N-acetyl-beta-D-glucosaminidase (NAG), which is present in renal tubular cells, is released into the urine in response to tubular insults. In this study, urinary NAG was measured before and after procedures to assess for ischemic renal injury. METHODS: A total of 31 patients underwent laparoscopic procedures while 28 patients had conventional surgery. Urine was obtained first at the time of preoperative Foley catheter placement and later during the recovery room stay. NAG levels were measured and indexed to urinary creatinine. RESULTS: Operative time for the laparoscopy group was 105 min (range, 15-255); for the conventional group, it was 179 min (range, 75-385) (P < 0.05). No differences were noted between pre- and postoperative NAG levels or between the groups. There was no correlation between urinary NAG levels and operative time. CONCLUSION: Pneumoperitoneum is not associated with a change in the urinary concentration of NAG. This finding suggests that there is no significant renal tubular injury associated with laparoscopic surgery.

Acetylglucosaminidase↗
PubMed1999

Laparoscopic bowel injury: incidence and clinical presentation.

PURPOSE: Bowel injury is a potential complication of any abdominal or retroperitoneal surgical procedure. We determine the incidence and assess the sequelae of laparoscopic bowel injury, and identify signs and symptoms of an unrecognized injury. MATERIALS AND METHODS: Between July 1991 and June 1998 laparoscopic urological procedures were performed in 915 patients, of whom 8 had intraoperative bowel perforation or abrasion injuries. In addition, 2 cases of unrecognized bowel perforation referred from elsewhere were reviewed. A survey of the surgical and gynecological literature revealed 266 laparoscopic bowel perforation injuries in 205,969 laparoscopic cases. RESULTS: In our series laparoscopic bowel perforation occurred in 0.2% of cases (2) and bowel abrasion occurred in 0.6% (6). The 6 bowel abrasion injuries were recognized intraoperatively and 5 were repaired immediately. In 4 cases, including 2 referred from elsewhere, perforation injuries were not recognized intraoperatively and they had an unusual presentation postoperatively. These patients had severe, single trocar site pain, abdominal distention, diarrhea and leukopenia followed by acute cardiopulmonary collapse secondary to sepsis within 96 hours of surgery. The combined incidence of bowel complications in the literature was 1.3/1,000 cases. Most injuries (69%) were not recognized at surgery. Of the injuries 58% were of small bowel, 32% were of colon and 50% were caused by electrocautery. Of the patients 80% required laparotomy to repair the bowel injuries. CONCLUSIONS: Bowel injury following laparoscopic surgery is a rare complication that may have an unusual presentation and devastating sequelae. Any bowel injury, including serosal abrasions, should be treated at the time of recognition. Persistent focal pain in a trocar site with abdominal distention, diarrhea and leukopenia may be the first presenting signs and symptoms of an unrecognized laparoscopic bowel injury.

Humans↗
PubMed1999

Benign prostatic hyperplasia (the aging prostate).

BPH is a common phenomenon of the aging process. Clinical manifestations may range from minimally bothersome symptoms to urinary retention and renal failure. Tailoring of treatment based on the individual patient is required for successful management. For mild symptoms, watchful waiting is a valid option. For severe symptoms, surgical therapy is most appropriate. For men complaining of moderate symptoms, medical therapy has become front-line therapy, with other less invasive treatment modalities being available or in development.

Aged↗
PubMed1999

Traumatic posterior urethral injury and early primary endoscopic realignment: evaluation of long-term follow-up.

OBJECTIVES: The management of complete or partial posterior urethral disruption is controversial and much debate continues regarding immediate versus delayed definitive therapy. We further analyze our experience and long-term results using early endoscopic realignment. METHODS: Between April 1991 and June 1995, 8 men with posterior urethral avulsion, either complete or partial and secondary to blunt trauma and pelvic fractures, presented to our institution. A variety of endourologic techniques were employed to achieve urethral continuity while attempting to minimize stricture formation, incontinence, and impotence. RESULTS: After a mean of 50.4 months (range 35 to 85) of follow-up, 7 men (87.5%) are continent, with 2 of those requiring intermittent self-dilation ranging from once every 7 days to once a month. One patient required conversion to an open perineal urethroplasty. Of the 8 patients, 5 (62.5%) are potent, and 2 others achieve adequate erections for intercourse using intracorporeal injections. Four of the 8 have required subsequent internal urethrotomies with eventual voiding stabilization over the course of 1 2 months. Average time to realignment was 9.5 days (range 0 to 19). CONCLUSIONS: Primary endoscopic realignment offers an effective method for treating traumatic urethral injuries. Our long-term follow-up provides further support for use of this technique by demonstrating that urethral continuity can be established without increased incidence of impotence, stricture formation, or incontinence. By achieving early and minimally invasive realignment, we seem to lessen the severity of stricture disease that almost uniformly afflicts those patients who undergo delayed repair. If a minimally invasive technique should fail, it does not seem to delay nor does it preclude further management using open techniques.

Adolescent↗
PubMed1999

Familial calcium stone disease: TaqI polymorphism and the vitamin D receptor.

BACKGROUND AND OBJECTIVE: Calcium nephrolithiasis has a strong familial component. However, to date, no specific genetic abnormality has been identified. Allelic variation in the vitamin D receptor (VDR) gene has been suggested as a partial explanation of differential calcium absorption or excretion in these patients. Polymorphism of this gene has been associated with altered vitamin D activity and has been implicated in osteoporosis and prostate cancer. We propose that a similar association may be found between familial hypercalciuric stone disease and the VDR. SUBJECTS AND METHODS: Genomic DNA was isolated from 37 controls and 19 patients with hypercalciuria (> 250 mg/24 hours) and a family history of nephrolithiasis. A 740-basepair segment of the VDR gene was amplified by polymerase chain reaction, digested with TaqI endonuclease, and resolved by gel electrophoresis. Alleles were classified as "T" if only one TaqI site was present and "t" if two were present. A simplified strength of family history score (FHS) was computed by adding 2 and 1 points, respectively, for each first- and second-degree relative affected by stone disease. RESULTS: No difference in allelic or genotypic frequencies between the study and control groups was present. In the stone group, a significant association was found between the strength of the family history and the TT genotype. Patients with this genotype had an average FHS of 4.0, whereas the mean FHS for the Tt and tt genotypes was 2.0 and 1.8, respectively (P < 0.05). Nonsignificant trends of the TT genotype toward a higher number of stone episodes (19 v 13 and 3) and higher 24-hour urine calcium excretion (408 v 297 and 353 mg) were also noted in the study group. CONCLUSION: The results suggest that the TT genotype is associated with more aggressive stone disease, both within families and with respect to recurrence. Quantifying the risk of calcium stone disease through DNA markers has potential application in determining the risk of a patient's family members for nephrolithiasis or a patient's risk of recurrence. This information may have therapeutic implications with regard to the rigor of medical therapy and frequency of follow-up.

Alleles↗
PubMed1999

Feasibility of total intravesical endoscopic surgery using mini-instruments in a porcine model.

BACKGROUND AND OBJECTIVES: The aim of minimally invasive approaches to vesicoureteral reflux, such as endoscopic trigonoplasty, is to lower the morbidity of open procedures without compromising the results. Initial successes have not been sustained, mainly because of trigonal splitting, which results in the ureteral orifices returning to their preoperative positions. This study was designed to address trigonal splitting by mobilizing the ureters before repositioning them and to evaluate the feasibility of accomplishing this intravesically with 2- to 3-mm endoscopic mini-instruments. METHODS: Bilateral vesicoureteral reflux was surgically created in 10 minipigs. After radiologic confirmation of success 4 weeks later, modified trigonoplasty was performed by endoscopic intravesical mobilization of both ureters and incision of the trigonal mucosa using 2-mm instruments. The ureteral orifices were then advanced toward the midline and sutured in place. The initial surgical techniques were modified to permit the entire procedure to be performed endoscopically in the last four minipigs. Cystograms and intravenous urograms were obtained 4 weeks later. RESULTS: Two minipigs died postoperatively. Six of the remaining eight had persistent reflux, including three of the four in the group treated completely by endoscopic means. None of the dissected ureters showed evidence of stricture or necrosis. CONCLUSIONS: Although the procedure was not successful in correcting reflux in this model, this study demonstrates the feasibility of endoscopic ureteral mobilization. With current instrumentation, there is no significant technical obstacle to complete intravesical endoscopic surgery, including ureteral reimplantation.

Animals↗
PubMed1999

Laparoscopic v laparoscopy-assisted donor nephrectomy in the porcine model.

PURPOSE: Laparoscopic donor nephrectomy is an established procedure in the porcine model. We sought to compare intraoperative variables between live laparoscopic (LAP) and laparoscopy-assisted (LAP-A) donor nephrectomy. MATERIALS AND METHODS: Eight domestic pigs underwent either traditional laparoscopic donor nephrectomy (N = 4) or laparoscopy-assisted donor nephrectomy (N = 4) using the Pneumosleeve followed by conventional heterotopic autotransplantation. RESULTS: No significant differences were noted between the groups with regard to vessel length, ureteral length, or postoperative urine output. The operating room time was 108+/-12 minutes in the LAP group v 75.8+/-10.3 minutes in the LAP-A group (P = 0.0065). Although the difference was not statistically significant, warm ischemic time, tended to be lower in the LAP-A than the LAP group: 70+/-3.0 seconds v 135+/-57 seconds, respectively (P = 0.059). Graft survival was identical in the two groups. CONCLUSION: Laparoscopy-assisted (via Pneumosleeve) live donor nephrectomy shortens the operative time without affecting graft survival in the domestic swine model.

Animals↗
PubMed1999

Retroperitoneal access for transperitoneal laparoscopy in patients at high risk for intra-abdominal scarring.

BACKGROUND AND PURPOSE: Adhesions from prior extensive open abdominal surgery can make initial transperitoneal access for laparoscopy hazardous. An alternative to open port placement is a retroperitoneal approach to the peritoneal cavity. We describe our retroperitoneal access for transperitoneal laparoscopy and evaluate the success of the subsequent laparoscopic procedure. PATIENTS AND METHODS: Eight patients with a history of abdominal surgery have undergone retroperitoneal access to the peritoneum prior to a laparoscopic urologic procedure. With the patient in a lateral decubitus position, the retroperitoneum is entered with a 10-mm Visiport device (US Surgical Corp., Norwalk, CT) along the posterior axillary line. A working space is bluntly created, the peritoneum identified anterior to the colon, and the endoscope passed through a peritoneotomy. The abdomen is then inspected, transperitoneal ports are strategically placed under direct vision, and the intended procedure is commenced. RESULTS: In all cases, retroperitoneal access to the peritoneum and subsequent trocar placement was successful. In five cases, the intended procedure was completed laparoscopically. In a case of bilateral ureterolysis, one side was completed laparoscopically; however, the other required open conversion. In two nephrectomies for xanthogranulomatous pyelonephritis (XGP), open conversion was necessary because of fibrosis. CONCLUSION: Retroperitoneal access to the peritoneal cavity permits safe and effective port placement when previous abdominal surgery makes initial transabdominal access difficult. However, despite successful access, in patients at risk for extensive perinephric fibrosis (e.g., XGP), a high incidence of open conversion may be expected.

Abdomen↗
PubMed1999

Citrate in the management of urolithiasis.

Citrate therapy for recurrent calcium urolithiasis has become common over the last decade. The hypotheses that chronic stone formers must have biochemical defects that increase recurrence risks have instigated medical therapy directed at these defects. The utilization of stone clinics, detailed metabolic evaluations, and meticulous follow-up of recurrent stone formers has led to a greater understanding and knowledge of treatment options. Citrate therapy has been used like aspirin in the medical community perhaps without a clear understanding of its mechanism of action and indications. This article provides a synopsis of citrate use in the medical and surgical treatment of urolithiasis.

Administration, Oral↗
PubMed1999

Laparoscopic genitourinary surgery utilizing 20 mm Hg intra-abdominal pressure.

Traditional practice has dictated that intra-abdominal pressure during laparoscopy be kept at or below 15 mm Hg to minimize the risk of cardiovascular and pulmonary complications. This study was undertaken to determine if maintaining an intra-abdominal pressure of 20 mm Hg could be utilized safely during genitourinary laparoscopy. We reviewed the intraoperative records of 76 consecutive patients undergoing various endoscopic urologic procedures at an intra-abdominal pressure of 20 mm Hg to assess physiologic changes and complications. The records were examined for operating time, minute ventilation (MV), end-tidal CO2 (ETCO2), and peak inspiratory pressure (PIP), which were compared with the preinsufflation values. Also, in the first 39 patients, initial insufflation volumes were recorded at 15 mm Hg and then again when pressure was raised to 20 mm Hg. The mean operating time was 186 +/- 90 min. There was an average 22% increase in the sufflated volume when the pressure was elevated from 15 to 20 mm Hg. To maintain a suitable ETCO2, the anesthesiologist needed to increase the MV an average of 2.9 +/- 2.0 L/min. Increases in ETCO2 (average 4.5 +/- 4.6 mm Hg) and PIP (6.9 +/- 3.6 mm Hg) were noted. In two cases, the intra-abdominal pressure had to be decreased from 20 to 15 mm Hg because of inability to maintain an acceptable ETCO2. Subcutaneous emphysema was noted in three patients, which resolved spontaneously within 24 hr. In one patient, asymptomatic pneumomediastinum was noted after a 6-hr procedure. Intra-abdominal insufflation can be safely maintained at 20 mm Hg in most patients. This higher pressure improves maintenance of the pneumoperitoneum.

Adult↗
PubMed1999

Laparoscopic versus open pyeloplasty: assessment of objective and subjective outcome.

PURPOSE: We determine the subjective and objective durability of laparoscopic versus open pyeloplasty. MATERIALS AND METHODS: From August 1993 to April 1997, 42 patients underwent laparoscopic pyeloplasty (laparoscopy group) with a minimum clinical followup of 12 months (mean 22). Subjective outcomes and objective findings were compared to those of 35 patients who underwent open pyeloplasty (open surgery group) from August 1986 to April 1997 with a minimum clinical followup of 12 months (mean 58). We assessed clinical outcome based on responses to a subjective analog pain and activity scale. In addition, radiographic outcome was assessed based on the results of the most recent radiographic study. RESULTS: Of the 42 laparoscopy group patients 90% (38) were pain-free (26, 62%) or had significant improvement in flank pain (12, 29%) after surgery. Two patients had only minor improvement and 2 had no improvement in pain. Surgery failed in only 1 patient with complete obstruction. A patent ureteropelvic junction was demonstrated in 98% (41 of 42 patients) of the laparoscopy group on the most recent radiographic study (mean radiographic followup 15 months). Of the 35 open surgery group patients 91% were pain-free (21, 60%) or significantly improved (11, 31%) after surgery. One patient had only minor improvement and 2 were worse. CONCLUSIONS: Pain relief, improved activity level and relief of obstruction outcomes are equivalent for laparoscopic and open pyeloplasty.

Adolescent↗
PubMed1999

Laparoscopic testicular denervation for chronic orchalgia.

PURPOSE: No specific cause is identified in most cases of chronic orchialgia. Nonsurgical therapies, including management at a chronic pain clinic, are generally recommended. Only when multiple conservative measures fail are patients offered surgical intervention, such as orchiectomy. We evaluate laparoscopic testicular denervation as an organ preserving and minimally invasive surgical alternative. MATERIALS AND METHODS: Since 1993, 9 patients with chronic orchialgia have undergone transperitoneal laparoscopic testicular denervation after nonsurgical modalities failed. Using 1, 10 mm. and 1 or 2, 5 mm. ports, the gonadal vessels were isolated circumferentially and divided cephalad to the vas deferens and its vasculature. Preoperative treatment modalities, morbidity and outcome were documented. A cord block provided temporary relief in all 9 patients. Analog scales were used to assess long-term pain relief (0 no pain to 100 worst pain) and activity levels (0 bedrest to 100 no restrictions). RESULTS: Average symptom duration before laparoscopic testicular denervation was 4.1 years. Of 9 patients 8 had undergone prior scrotal surgery. Failed nonsurgical modalities included anti-inflammatory drugs in 7 patients, antibiotics in 6, pain clinic consultations in 4 and antidepressant medications in 2. Mean pain score decreased from 69.4 (range 35 to 90) preoperatively to 30.6 at a mean followup of 25.1 months. Excluding the 2 cases that had no pain relief (less than 10-point reduction), average pain score decreased from 69 to 19 postoperatively (mean reduction 71%). Activity levels improved in all cases. There were no significant complications, including testis atrophy. One patient who had no pain relief underwent subsequent hydrocelectomy for pain, which also failed. CONCLUSIONS: Laparoscopic testicular denervation can provide significant long-term pain relief and appears to be a reasonable alternative in select cases with chronic orchialgia refractory to medical therapy. Larger series and prospective evaluations are necessary.

Adult↗