Biomedical subjects

R V O'Toole

Publications and source records attributed to R V O'Toole.

At least 19 recordsLinked to original sources

PubMed1999

Measuring and developing suturing technique with a virtual reality surgical simulator.

BACKGROUND: We have developed an interactive virtual reality (VR) surgical simulator for the training and assessment of suturing technique. The surgical simulator is comprised of surgical tools with force feedback, a 3-dimensional graphics visual display of the simulated surgical field, physics-based computer simulations of the tissues and tools, and software to measure and evaluate the trainee's performance. STUDY DESIGN: This study uses the simulator to measure and compare the skills of 8 experienced vascular surgeons versus 12 medical students when performing a virtual reality suturing task. Eight parameters of the suturing task were measured: total tissue damage, accuracy of needle puncture, peak tissue tearing force, time to complete the task, damage to the surface of the tissue, angular error in needle technique, total distance traveled by the tool tip, and a measure of overall error. Three test conditions (dominant hand, nondominant hand, and 3-dimensional needle guide) were tested. Statistical significance was defined as a univariate two-sided p value < or = 0.05. RESULTS: The surgeons' average performance was significantly better than the students' average performance for three of the measured parameters (total tissue damage, time to complete the task, and total distance traveled by the tool tip) for each of the test conditions. For the test condition most similar to surgery (using the dominant hand to suture) one additional parameter was also significantly different (the measure of overall error). The medical students showed improvements for 6 of the 7 parameters for which the users received feedback during the training process. The surgeons also had significant improvement for 4 of the 7 parameters. The students had a larger improvement than the surgeons for 6 of the parameters, but these differences were not statistically significant. CONCLUSIONS: Data indicate differences between surgeon and nonsurgeon performance and in improvement in performance with training. One possible explanation for the superior performance of the surgeons is that their suturing skills applied well to the simulated suturing task. Additional research is required to confirm or deny the similarity between actual and simulated surgical tasks and the relevance of virtual reality surgical simulation to surgical skill assessment and training.

Computer Simulation↗

PubMed1999

Melanosis of the uterine cervix: a report of two cases and discussion of pigmented cervical lesions.

Two cases of cervical melanosis, an uncommon process characterized by hyperpigmentation of the basal epithelium, with or without accompanying basal melanocytes, are reported. The etiology of cervical melanosis is uncertain but may represent a metaplastic change in response to trauma or chronic irritation. On gross examination, it is not possible to reliably separate the different causes of cervical pigmentation; consequently, any pigmented cervical lesion should be biopsied.

Adult↗

PubMed1996

Automated screening for quality control using PAPNET: a study of 638 negative Pap smears.

To determine if the PAPNET screening system can be used for quality control to lower false-negative rates for Pap smears 638 manually screened, "negative" Pap smears were subjected retrospectively to the PAPNET screening system. Twenty-nine of the smears came from 18 patients who subsequently had biopsyproven high-grade squamous intraepithelial lesions (SIL). The remaining 609 negative smears were arbitrarily selected as controls. One hundred twenty-eight (128) of the retrospectively reviewed smears (20%) were selected by PAPNET for microscopic referral because of potential abnormalities. Abnormalities were confirmed on 14 of these smears upon microscopic evaluation. Five of these 14 smears were from smears obtained from four of the 18 women with high-grade SIL. The incidence of manually screened false-negatives detected by PAPNET rescreening was 14/638 or 2.2% for the entire patient population in this study and 5/29 or 17.24% for the targeted patients known to have subsequently developed highgrade lesions. The 2.2% decrease in the false-negative rate in this experiment may be partly artificial as this study group was seeded with false-negative cases at high risk for containing missed abnormalities. The implementation of the PAPNET system for quality control may lower false-negative rates for Pap smears.

Automation↗

PubMed1996

Intraperitoneal mitoxantrone or floxuridine: effects on time-to-failure and survival in patients with minimal residual ovarian cancer after second-look laparotomy--a randomized phase II study by theSouthwest Oncology Group.

A randomized phase II study of intraperitoneal (ip) mitoxantrone or floxuridine (FUDR) was performed for the treatment of minimal residual epithelial ovarian cancer found at second-look laparotomy after initial platinum-based chemotherapy. Entry was to take place within 30 days of reassessment laparotomies, with documentation of peritoneal metastases either microscopic or gross with cytoreduction to less than or equal to 1 cm in largest diameter. Patients were stratified by the site of the largest disease present (microscopic to 0.5 cm maximum diameter versus greater than 0.5 to 1 cm maximum diameter), by time of registration (< 14 days versus up to 30), and by serum CA-125 (< or = 35 versus >35 units/ml) prior to randomization to either ip mitoxantrone 10 mg/m2 every 2 weeks X 9 or ip floxuridine (FUDR) 3 g (total dose)/ day X 3 days every 3 weeks X 6 cycles. Implantable ip systems and 1.5-2 liters of normal saline were used to deliver the drugs of 83 patients registered between December 1988 and January 1994; there were 6 pathology exclusions and 9 surgical exclusions, and 1 nonevaluable patient for a total of 39 evaluable on mitoxantrone and 28 on FUDR being evaluable. FUDR is the choice for further study because of a progression-free survival exceeding 15% at 1 year over mitoxantrone and a median overall survival of 38 months. It should be emphasized again that the goal of a randomized phase II selection design is to select a winner for phase III testing should there be a substantial difference between the treatments with respect to the primary endpoint. Comparative conclusions between the treatment arms should not be attempted due to the inherently much smaller sample sizes. This should reemphasize the limitations in a comparison of efficacy; however, the toxicologic differences still emerge quite clearly.

Adult↗

PubMed1996

Endometriosis with myxoid change simulating mucinous adenocarcinoma and pseudomyxoma peritonei.

A case of endometriosis with myxoid change is presented here which raised concern for metastatic adenocarcinoma and pseudomyxoma peritonei. This is the second case similar to the one described previously in the literature. A 51-year-old woman underwent repair for an umbilical hernia. The tissue sections of the hernia specimen contained isolated pools of mucin surrounded focally by cuboidal-type epithelium. Subsequent CT scan of the abdomen and pelvis revealed a large right adenexal mass. These clinicopathologic findings raised strong suspicion for adenocarcinoma and pseudomyxoma peritonei. Intraoperative frozen section of the right ovary showed an endometriotic cyst. She underwent hysterectomy, bilateral salpingoophrectomy, partial omentectomy, and lysis of adhesions. Permanent sections revealed foci of endometriosis in both ovaries and cervix. Pools of acellular mucin were present in the omentum and bladder peritoneum. There was no evidence of malignancy in any of the specimen. The case illustrates that endometriosis with myxoid change can simulate with mucinous adenocarcinoma and pseudomyxoma peritonei.

Adenocarcinoma, Mucinous↗

PubMed1996

A phase II trial of piroxantrone in endometrial cancer: Southwest Oncology Group study 8918.

A phase II trial of the new anthrapyrazole piroxantrone was carried out by the Southwest Oncology Group in patients with advanced metastatic or recurrent endometrial cancer. A two-stage statistical design targeted accrual of 20 eligible patients. The starting dose of piroxantrone was 150 mg/m2 in patients without prior radiation therapy (RT) and 120 mg/m2 in patients with prior RT. There were 15 eligible patients, six of whom had received prior hormonal therapy while nine patients had not received prior hormonal therapy. Eight patients had received prior RT while seven patients had not received any prior RT. One to seven cycles of piroxantrone were administered. Dose escalation was feasible in four patients. No grade 5 toxicity was experienced by any patients. Most of the grade 4 (granulocytopenia in one) and grade 3 (leukopenia in three, granulocytopenia in three, anemia in two and thrombocytopenia in one) toxicity was related to myelosuppression. Grade 3 non-hematologic toxicities were nausea, fatigue and SGOT elevation. There was one partial response for a response rate of 7% (95% CI 0.2-32%) and median survival was 11 months (95% CI 3-13 months). The study was prematurely terminated due to lack of patient accrual.

Adult↗

PubMed1995

A phase II trial of piroxantrone in advanced ovarian carcinoma after failure of platinum-based chemotherapy: Southwest Oncology Group Study 8904.

A phase II trial of the new anthrapyrazole piroxantrone was conducted by the Southwest Oncology Group in advanced ovarian carcinoma. The objective were to evaluate its response rate and toxicity in patients who had disease persistence, progression, or recurrence either during or after platinum-containing chemotherapy. A two-stage statistical design targeted accrual to 15 eligible patients if no responses were observed. The piroxantrone starting dose was 120 mg/m2, with the provision to escalate to 150 and 180 mg/m2. There were 16 eligible patients, all of whom had received either one (12 patients) or two (4 patients) prior platinum-containing regimens; one patient had received doxorubicin. Fourteen of the 16 patients were enrolled either at the time of disease persistence/progression during initial chemotherapy or with recurrence or progression within 6 months of the previous platinum-based remain. One to 5 cycles of piroxantrone were given. Dose escalation was feasible in 7 patients but was prevented in the other 9 by neutropenia. Maximum toxicity for all cycles was none or grade 1 in 2 patients; grade 2, 5; grade 3, 8; and grade 4, 1. All but one of the grade 3 or 4 events was from myelosuppression; there were no adverse cardiac events. No responses were observed. Thus, piroxantrone appears inactive in patients with persistent, progressive, or recurrent ovarian cancer who recently had received a platinum-based regimen.

Adult↗

PubMed1995

Splenectomy as part of cytoreductive surgery for ovarian carcinoma.

Splenectomy is sometimes necessary to achieve optimal cytoreduction or manage iatrogenic injury in the surgical management of epithelial ovarian cancer (EOC) and related conditions. To determine the place of splenectomy in cytoreductive surgery a retrospective review was made of patient hospital records. Between April 1989 and August 1994, 18 patients were found to have undergone a splenectomy as a component of their surgery leading to optimal debulking. Morbidity attributable to the splenectomy was minimal, with no significant increase in operative time or blood loss. The morbidity attributable to the splenectomy was as follows: atelectasis and/or effusion (8), pancreatic tail injury (4), thrombocytosis > 10(6)/microliters (3), pancreatic pseudocyst (1), partial left adrenalectomy (1), and pulmonary embolism (1). There were no instances of overwhelming postsplenectomy infection. Five patients were anticipated to require splenectomy and may have benefitted from preoperative vaccination against potential pathogens. Three patients were found to have splenic parenchymal metastases. Consistent with the international literature, these patients had other features consistent with stage IV disease, recurrent disease, or poor survival. Consideration should be given to expanding the FIGO stage IV classification to include splenic parenchymal disease. Splenectomy is a feasible and safe procedure to facilitate optimal tumor debulking; however, the potential associated morbidity mitigates against this procedure if significant, suboptimal residual disease is left elsewhere.

Adult↗

PubMed1995

Biomechanics for preoperative planning and surgical simulations in orthopaedics.

Surgical simulations are particularly appropriate for the large volume and expense of joint replacement procedures in orthopaedics. A first generation surgical simulator has been developed to model the implantation procedure for cementless acetabular and femoral components in total hip replacement surgery. The simulator is based upon finite element analysis and predicts the early postoperative mechanical environment that results from a proposed surgery. Since the short- and long-term clinical success of cementless hip replacement components is very dependent upon the initial mechanics of the bone-implant system, such simulations can help orthopaedic surgeons to develop better preoperative plans.

Biomechanical Phenomena↗

PubMed1993

Antiestrogenic potency of toremifene and tamoxifen in postmenopausal women.

In this nonblinded, controlled multicenter trial, postmenopausal women were randomly assigned to receive graded doses of toremifene and tamoxifen or no antiestrogen to assess dose-response levels and evaluation methodology. For standardization, transdermal estradiol (Estraderm-Ciba Geigy) was applied to all women for 38 days. The antiestrogens were added on days 29-38. For control and all treatment groups, there were no significant changes in serum chemistries or serum hormone levels, nor were there differences in adverse effects. The use of continuous estradiol precluded any meaningful assessment of the estrogenicity of tamoxifen or toremifene. As measured by vaginal superficial cytologic cell count changes, the antiestrogenic activity of toremifene doses ranging from 20 to 200 mg/day could not be distinguished from that of 20 mg/day of tamoxifen, the clinically recommended dose in North America.

Adult↗

PubMed1992

Phase II trial of amonafide in previously treated patients with advanced ovarian cancer: a Southwest Oncology Group study.

Twenty-three patients with metastatic or recurrent Stage III or IV epithelial ovarian cancer who were refractory to or relapsed following previous chemotherapy with cisplatin or a cisplatin analog were entered into a phase II study of amonafide. The starting dose of amonafide was 300 mg/m2 delivered daily over 1 hr by intravenous infusion. In the absence of myelosuppression, the dose of amonafide was escalated by increments of 75 mg/m2 to a maximum of 450 mg/m2. There were 19 eligible and 17 fully evaluable patients. Grade 3 or 4 leukopenia occurred in 14 (74%) patients and grade 3 or 4 thrombocytopenia in 6 (32%) patients. No objective complete or partial responses were observed. Four patients had stable disease for 3, 4, 4.5, and 6 months, respectively. Therefore, amonafide in the doses used in the present trial does not have significant activity in previously treated patients with ovarian cancer.

Adenine↗

PubMed1992

Randomized comparison of cisplatin plus epirubicin or doxorubicin for advanced epithelial ovarian carcinoma. A multicenter trial.

Stage III and IV epithelial ovarian cancer patients were prospectively randomized to receive eight courses of 60 mg/m2 of cisplatin plus either 75 mg/m2 of epirubicin (62 patients) or 60 mg/m2 of doxorubicin (54 patients). Clinical response rates for cisplatin/epirubicin of 42% [15% complete response (CR) and 27% partial response (PR)] and for cisplatin/doxorubicin of 55% (24% CR and 31% PR) were not statistically different (p = 0.14). The negative second look rate was 35% (10/29) for cisplatin/doxorubicin and 17% (5/30) for cisplatin/epirubicin (p = 0.12). The progression-free interval for cisplatin/epirubicin (13 months) was not statistically different (p = 0.09) from that for cisplatin/doxorubicin (19 months). The median survivals for cisplatin/epirubicin (756 days) and cisplatin/doxorubicin (739 days) were similar (p = 0.70). Cardiotoxicity was greater for the cisplatin/doxorubicin group (p = 0.0003). With similar survival and less cardiotoxicity, the cisplatin/epirubicin regimen had the more favorable therapeutic index.

Adolescent↗

PubMed1992

A phase II evaluation of esorubicin in ovarian cancer. A Southwest Oncology Group study.

Patients with a pathologically confirmed diagnosis of metastatic or advanced epithelial-type ovarian carcinoma were entered into a Phase II trial of esorubicin. Eligibility criteria included measurable disease; performance status (SWOG) 0-2; no more than one prior chemotherapeutic regimen; and no prior doxorubicin therapy. The starting esorubicin dosing schedule was 30 mg/m2 every 3 weeks for good risk patients and 25 mg/m2 every 3 weeks for poor risk patients. Twenty-one patients were eligible for evaluation of response and toxicity to treatment. These patients received a median of 3 courses of esorubicin (range 1-13 courses). None of the 21 patients experienced a response to esorubicin. Median survival was 5.5 months. Leukopenia was the major toxicity. Eleven (79%) of the good risk patients and 2 (29%) of the poor risk patients experienced severe to life-threatening leukopenia. Mild to severe anemia was seen in 10 (71%) of the good risk patients and 7 (100%) of the poor risk patients. We conclude that esorubicin is ineffective in the treatment of ovarian cancer patients who have received primary chemotherapy.

Aged↗

PubMed1991

DNA ploidy and prostate-specific antigen as prognostic factors in clinically resectable prostate cancer.

Prostate-specific antigen (PSA) and DNA ploidy as measured by flow cytometry were compared with conventional prognostic indicators in 112 patients who underwent radical prostatectomy for clinically resectable prostate cancer. The variables examined included age, race, prostatic acid phosphatase (PAP), Gleason score of the radical prostatectomy specimen, and pathologic stage. No significant relationships were found between DNA ploidy and age, mean PAP value, and absolute PAP value. Of the 112 patients, 65 (58.0%) had disease limited to the prostate (pathologic Stages A and B); 47 (42.0%) had extraprostatic disease (pathologic Stages C and D1). The stage was related to the Gleason score (P less than 0.0001) where extraprostatic disease was associated with a Gleason score of 6 to 10. Nineteen (17.0%) patients had aneuploid tumors, and 93 (83.0%) had diploid tumors. DNA ploidy significantly correlated with pathologic stage (P = 0.04); aneuploidy was identified more frequently in patients with Stages C and D1 tumors. Aneuploid tumors occurred more frequently than diploid tumors in patients with a Gleason score of 6 to 10 (P = 0.034). Mean PSA values were higher in patients with aneuploid tumors (P = 0.078), extraprostatic neoplasms (P = 0.00001), and cancers with a Gleason score of 6 to 10 (P = 0.0004). Furthermore, PSA values greater than 10.0 ng/ml were associated with extraprostatic disease and a Gleason score of 6 to 10 (P less than 0.05 and P less than 0.001, respectively). Significant racial differences were found with respect to DNA ploidy, mean DNA indices, and mean PSA values. The 18 black patients had more DNA aneuploid tumors (P = 0.043), a higher mean DNA index (P = 0.017), and a higher mean PSA value (P = 0.043) than the 94 white patients. Both PSA and DNA ploidy analysis by flow cytometry appear to be valuable indicators in the evaluation of patients with prostatic carcinoma.

Acid Phosphatase↗

PubMed1991

Esorubicin in advanced endometrial cancer: an ineffective and potentially toxic therapy. A Southwest Oncology Group study.

The Southwest Oncology Group conducted a phase II study of esorubicin treatment in patients with advanced endometrial cancer who had received no prior chemotherapy. Twenty of 31 patients were fully evaluable for response and toxicity. There were no clinical responses to treatment and 60% (12/20) of the patients developed severe or life threatening leukopenia on therapy. One evaluable patient was removed from study after a cumulative dose of 150 mg/M2 due to a reduction in left ventricular ejection fraction on MUGA scan and another developed congestive heart failure several months after discontinuation of treatment. Esorubicin has significant toxicity and limited clinical activity in patients with advanced endometrial cancer.

Antibiotics, Antineoplastic↗

PubMed1990

Is DNA ploidy an independent prognostic indicator in infiltrative node-negative breast adenocarcinoma?

To evaluate DNA content as an independent, long-term prognostic indicator in infiltrative, node-negative adenocarcinoma of the breast, flow cytometric DNA analyses were performed retrospectively in 165 patients. The exclusive use of paraffin-embedded tissue permitted the study of patients for whom 3 to 15 years' follow-up was available. Other investigators have shown a relationship between DNA nuclear content and well-known prognostic indicators of breast carcinoma, such as estrogen receptors, age, menopausal status, and stage of tumor. However, very few of these studies were based on patients with long-term clinical follow-up and investigated the independent prognostic value of DNA nuclear content. The frequency of aneuploidy in the patients in this study was 57%, with DNA indices ranging from 0.73 to 2.59. Survival in patients with localized breast carcinoma with DNA aneuploid tumors was 84.1% at 5 years and 75.5% at 10 years. Those with diploid tumors showed survival of 87.8% at 5 years and 73.4% at 10 years. These data show no independent prognostic value for DNA nuclear content. The relationship between DNA content, tumor histologic type, and age was also investigated. High-grade tumors were more often aneuploid. There was no association between DNA content and age. Of 165 patients, information regarding estrogen receptor status was available in only 77; 45% of those with aneuploid tumors and 35% with diploid tumors were estrogen receptor-negative. This difference was not significant. The authors conclude that simple determination of DNA ploidy fails to indicate prognosis for infiltrative, node-negative breast carcinoma.

Adenocarcinoma↗

PubMed1990

Prognostic factors in patients with primary transitional cell carcinoma of the upper urinary tract.

A total of 50 patients with primary transitional cell carcinoma of the upper urinary tract underwent deoxyribonucleic acid ploidy characterization by flow cytometric analysis of paraffin embedded specimens. The primary tumor was diploid in 29 patients (58%) and aneuploid in 21 (42%). Aneuploidy was identified more frequently in grade 3 than in grades 1 and 2 neoplasms (p = 0.001). Additionally, grade 3 neoplasms occurred more often with invasive (stages T2 to T3) compared to superficial (stages TA, TIS and T1) tumors (p = 0.002). However, deoxyribonucleic acid ploidy was not significantly associated with tumor stage. Among the 49 patients treated by a definitive operation the median survival free of disease and median over-all survival were 33.7 and more than 120 months, respectively. Variables examined included deoxyribonucleic acid ploidy, tumor grade, tumor stage, primary tumor site and type of operation. In the univariate analysis deoxyribonucleic acid ploidy was the only significant predictor of survival free of disease (p = 0.04). Aneuploid tumors had a median survival free of disease of 19 versus 59 months for diploid tumors. However, in the multivariate analysis of factors affecting survival free of disease, the type of operation performed was the only significant variable. Patients undergoing nephroureterectomy with en bloc bladder cuff excision had a favorable survival free of disease (p = 0.04). Tumor stage was the only significant factor associated with over-all survival in univariate and multivariate analyses (p = 0.02 and 0.005, respectively). Patients with superficial tumors had a median survival of more than 120 versus 72 months for patients with invasive tumors. The data suggest that deoxyribonucleic acid ploidy may be a useful parameter to identify risk groups and plan the management of patients with primary transitional cell carcinoma of the upper urinary tract.

Carcinoma, Transitional Cell↗

PubMed1990

Flow cytometric analysis of primary and metastatic bladder cancer.

A total of 22 patients with high grade P2-4N+ transitional cell carcinoma of the bladder underwent flow cytometric analysis of nuclei obtained from paraffin embedded specimens from the primary (bladder) and metastatic (lymph node) sites. Tumor heterogeneity was defined as polyclonal aneuploidy of the primary tumor (not identified in the population studied) or as a difference in the deoxyribonucleic acid index of the primary and metastatic sites of 0.20 or more (8 patients). With these criteria 8 patients (36%) had heterogeneous tumors and 14 (64%) had homogeneous tumors. The median survival of 14 patients with aneuploid and 8 with diploid primary tumors was 17.5 and 8.0 months, respectively (p equals 0.08, Lee-Desu test). When patient survival was compared to the ploidy of the metastatic site, or in patients with diploid primary and metastatic lesions versus deoxyribonucleic acid aneuploidy at either the primary and/or metastatic site, the aneuploid tumors had a longer survival but this difference was not significant (p equals 0.13 and 0.23, respectively). Our study demonstrates the value of flow cytometry to identify primary metastatic tumor heterogeneity. It also suggests that the presence of metastasis may be a more important factor to define the biological potential of transitional cell carcinoma than is deoxyribonucleic acid ploidy.

Aged↗