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Biomedical subjects

R D Tucker

Publications and source records attributed to R D Tucker.

At least 37 records · Page 2Linked to original sources
PubMed1991

The in vivo effect of regional hyperthermia on dunning R3327 prostatic tumor.

This report describes the in vivo effect of regional hyperthermia on male Copenhagen rats implanted with Dunning R3327 prostatic carcinoma. In six rats, a 22-gauge 1.5-cm needle was inserted into the tumor and heated to 46.5 degrees C for 2 hr. Two hyperthermia treatments were administered 48 hr apart. In a separate group of six rats, the needle was inserted into the tumor, but not heated. After treatment, serial measurements of tumor volume and body weight were made twice a week for 4 weeks. From the first day of measurement to day 22, the tumor size in the treated group compared to control was significantly smaller, P = 0.02. In the first 12 days following treatment, the mean value of body weight in the treated and control groups decreased 7% and 3%, respectively. Following this, body weights increased to baseline levels by the end of the study. No other side effects related to hyperthermia were observed and no immediate mortality occurred. In the control group, two rats died from lung metastasis of the prostatic carcinoma after day 22. In the treated group, no lung metastases were found and no rats died before being sacrificed on day 29. Our experiments show that local elevation of the temperature of the Dunning tumor results in the death of tumor cells; at 46.5 degrees C for 2 hr there is marked tumor damage while the rats tolerated the hyperthermia well.

Adenocarcinoma↗
PubMed1991

The interaction of electrosurgical bipolar forceps and generators on an animal model of fallopian tube sterilization.

Electrosurgical tubal sterilization with bipolar forceps has shown a variable and, in certain studies, a high failure rate. Some physicians have questioned if failure rates are due to an incompatibility between bipolar forceps and bipolar generators of different manufacturers. This manuscript presents data on tissue desiccations performed on a rat uterine horn model that uses two bipolar forceps of quite different designs and two popular bipolar generators. The data demonstrate that if an appropriate amount of energy, between 100 and 117 J, is applied to the tissue, consistent destruction occurs, regardless of the generator-forceps combination used. Histologic examination of the desiccated uterine horns displayed complete occlusion of all samples 8 weeks after the procedure. However, immediately and at 3 weeks after the procedure patent uterine horns were found. In the patent samples most samples displayed considerable electrosurgical damage.

Animals↗
PubMed1991

On the nesting of snowbirds: a question about seasonal and permanent migrants.

This essay asserts that seasonal and permanent migration may be connected, although there is no direct evidence for this relationship in the current research literature. We draw circumstantial and incomplete evidence for this proposition from findings of a recent survey of Canadian snowbirds in Florida and a parallel study of Canadian-Americans using the 1980 census public use sample migrant file. Other researchers are encouraged to settle the issue by including appropriate items in surveys of snowbirds that would determine whether or not some of the permanent migrants from the same origin serve as an unofficial reception committee for winter visitors, providing for them a socially receptive place to "nest" for the season.

Aged↗
PubMed1991

Do surgical gloves protect staff during electrosurgical procedures?

Fifteen pair of commercially available gloves were tested under conditions that occur during radio frequency electrosurgery to determine their potential to cause burns or shocks. Two pair of gloves showed a hydration effect that produced sufficiently low direct current resistance, 1500 and 5000 ohms, to be a potential shock or burn hazard. All intact gloves passed in excess of 0.75 A of radio frequency current by capacitive coupling. Eleven pair of gloves displayed dielectric breakdown of the latex or neoprene at voltages between 2200 and 2600 volts; the remaining gloves ranged from 5800 to 7000 volts. Under specific conditions all gloves tested have the potential to cause burns or shocks to the surgeon during electrosurgical procedures. To avoid burns, shocks, or glove perforation, surgeons should be aware of situations that put them at high risk.

Burns↗
PubMed1990

In vivo effect of 5 French bipolar and monopolar electrosurgical probes on the porcine bladder.

Previous in vitro studies have indicated bipolar electrosurgical probes would electrodesiccate tissue in a normal saline solution. This study applies similar sized monopolar and bipolar electrosurgical probes to porcine bladder in order to compare each probe's effect in vivo. The power delivered by each probe was calculated; the width and depth of the porcine bladder damage was measured and the volume of the damage calculated. The animals were sacrificed at 24, 48 and 96 h post-procedure so that the amount of tissue destruction could be quantitated relative to the bladder's natural tissue reaction. The data shows the power (watts) delivered by the monopolar probe to be approximately six times that of the bipolar probe. Likewise, the area of bladder wall damage was larger with monopolar at all time periods sampled and showed significant differences at 24 and 48 h. These studies indicate that in viable bladder, tissue bipolar probes will electrodessicate at a lower power and with less shortterm tissue damage.

Animals↗
PubMed1990

Use of 5F bipolar electrosurgical probe in endoscopic urological procedures.

Experimental data have shown bipolar electrodes to function in saline solution with less volume and depth of tissue destruction compared to similar sized monopolar electrodes. We applied the same bipolar generator and electrodes used in laboratory testing in 41 procedures on 36 patients to determine if the bipolar electrode will provide clinically adequate hemostasis. The bipolar electrode was used for bladder fulguration in 37 procedures and ureteral fulguration in 4. The procedures were performed by 7 urological surgeons and in normal saline solution. The bipolar electrode was believed to perform as well as the standard monopolar probe in 39 procedures. The 2 failures included 1 bladder tumor fulguration and 1 electroincision of a ureterointestinal anastomotic stricture. There were no episodes of recurrent bleeding after any procedure. The bipolar system has the added advantage of not requiring a return electrode (ground pad), thereby eliminating the possibility of skin burns.

Ambulatory Surgical Procedures↗
PubMed1990

In vivo evaluation of monopolar versus bipolar electrosurgical polypectomy snares.

The energy required and tissue damage in bipolar and monopolar polypectomy snares were compared in a canine model. The bipolar snare required an average of 34 joules of energy, whereas the monopolar snare required 228 joules to cut the same diameter of gastric mucosa tended into a polypoid structure (p = 0.0005). The reduced energy delivered to the tissue from the bipolar procedure resulted in only 32% average depth of damage to the underlying gastric wall, whereas the monopolar procedure caused an average 69% (p = 0.001). Surgically created polyps required 247 joules and 69 joules for corresponding monopolar and bipolar polypectomy (p = 0.001). The decreased energy required and the correspondingly reduced damage caused to the underlying bowel wall by the bipolar snare should reduce the incidence of perforation and post-polypectomy syndrome. The bipolar snare completes a local circuit about the snare, eliminating the return electrode and, consequently, the possibility of any return electrode burns. The bipolar snare thus provides an added safety margin during polypectomy.

Animals↗
PubMed1989

Management of benign ureteral structures: open surgical repair or endoscopic dilation?

We reviewed 20 cases of ureteral strictures, 15 of which were secondary to ureteral trauma. Of the patients 6 were managed initially by open repair and 14 underwent endoscopic manipulation. All 6 open repairs were successful, compared to 9 of the 14 patients who underwent endoscopic dilation of the ureteral stricture. Of the 5 failures 3 were due to the inability to cannulate the strictured ureter with a guide wire and 2 failed to respond to balloon dilation. Of these 5 patients 4 were treated successfully by an open operation. There were no serious intraoperative or postoperative complications. The average hospitalization was less for the endoscopic group (2.1 days) compared to the open surgical group (8.3 days). Followup ranged from 6 to 48 months.

Adult↗
PubMed1989

A comparison of urologic application of bipolar versus monopolar five French electrosurgical probes.

Urologic endoscopic procedures often involve electrosurgery. Recently bipolar probes have become commercially available. This study compares monopolar and bipolar electrosurgical probes in relation to power losses in urologic endoscopic instruments with the infusion of sterile water and saline, and the power transmitted by probes to tissue correlated to tissue destruction in each fluid. The power losses through each instrument in both solutions were minimal. The bipolar electrode functioned at a much lower power output than did the monopolar electrode. The bipolar probe was also more effective in saline than sterile water. The depth, width and volume of tissue damage for both electrodes were found to vary with generator power output. The data shows the burns had similar diameters for both probes but the bipolar probe caused significantly less burn depth than the monopolar probe. These initial studies indicate that bipolar electrodes can function in normal saline with less depth damage compared to the monopolar probe.

Animals↗
PubMed1984

Survival rates in undifferentiated small-cell carcinoma of the bronchus. A review and 2 case reports.

Patients with inoperable undifferentiated small-cell (oat cell) carcinoma of the bronchus rarely survive for long. The number of long-term survivors has always been variable and treatments given to them have differed markedly. In this article we present 2 patients who have survived for 6 1/2 years and 10 years respectively. These are the only patients surviving beyond 5 years out of 311 patients treated over a 30-year period. The literature on survival of patients with this type of carcinoma is reviewed.

Adult↗
PubMed1984

Radical irradiation and misonidazole for T2 grade III and T3 bladder cancer: 2 year follow-up.

Patients with T2 grade III and T3 bladder cancer were treated in a Phase II trial of radical irradiation plus Misonidazole (MISO). Forty Gy in 2 Gy fractions (5 per week) to the whole pelvis were followed by 12 Gy in 6 Gy fractions (1 per week) plus oral and intravesical MISO to a coned down volume. Twenty-two patients were treated and the results compared with historical controls. The cystoscopic complete tumor response between 6 and 12 months post therapy were 73 and 43%, respectively. The patient two year survival was 81 and 51%, respectively, and the patient 2 year survival with bladder preservation was 61 and 48%, respectively--4 patients in the MISO study having undergone salvage cystectomy. Complications that may be radiation related in the MISO study are wound sepsis after salvage cystectomy in 2 patients, rectal stenosis requiring colostomy 16 months after salvage cystectomy in 1 patient and the development of a contracted bladder in 1 patient with a history of prior extensive endoscopic therapy. No misonidazole neurotoxicity seen. These findings are being further evaluated in a prospective randomized trial.

Adult↗
PubMed1984

Demodulated low frequency currents from electrosurgical procedures.

Low frequency currents produced incidental to electrosurgical procedures are usually only a minor threat unless they are coupled directly into the heart through a catheter or a thoracic surgical procedure. However, should the low frequency blocking capacitors in the electrosurgical generator fail in the conducting state, extremely dangerous low frequency currents of many milliamperes may flow into the patient. Even with properly functioning capacitors, low frequencies up to several milliamperes may be produced by some generators. The results of this study show that the coagulation mode of operation produces greater amounts of low frequency currents than the "pure cutting" mode at the same power setting. These results also demonstrate that the higher the generator power output, the higher the magnitude of the low frequency currents.

Animals↗
PubMed1983

Comparison of chemotherapy alone versus chemotherapy and radiation therapy of extensive small cell carcinoma of the lung.

In a randomized study 145 patients with extensive small cell carcinoma of the lung were treated with chemotherapy alone (Cytoxan, CCNU, methotrexate) or with the same drug regimen and with radiation therapy to the brain, chest, and abdomen. One hundred eighteen of these patients were evaluable. Those patients receiving radiation had a better response rate (55% vs 31%, P = .016) but significantly greater toxicity. There was no significant difference in rates of complete response (7% vs 8%) or in survival (median 18.4 vs 15.3 weeks) between the two groups overall. The median survival of those patients with a partial response to therapy was 18 weeks; for those achieving a complete response it was 46 weeks. However, a clear difference in survival comparing responders with non-responders was evident only for patients who were assigned to chemotherapy alone. Partial regressions have little, if any, correlation with improvement in survival. Therapy in this disease must be oriented toward inducing complete response.

Aged↗
PubMed1983

Radical irradiation of T2 grade III and T3 bladder cancer--tumor response and prognosis.

A retrospective review was undertaken of the records of 69 patients treated by radical irradiation between 1972 and 1977 for T2 Grade III and T3 bladder cancer. Twenty-six of the patients were treated to a tumor dose of 54 Gy in 2 Gy fractions using five daily fractions per week and 24 of the patients were treated to a tumor dose of 48.6 Gy in 3.47 Gy fractions given tri-weekly. The tumor response and its relationship to patient five year survival with bladder conservation was determined. Tumor response was assessed on the basis of the documented gross cystoscopic findings between 6 and 12 months after radiotherapy. This could be done in 63 of the 69 patients. The complete response rate was 43%. The five year survival rate with bladder conservation for all the patients in the study was 24%; for those with a complete response at cystoscopy, 54%; and for those failing to achieve a complete response, 5.8%. A statistically significant improvement in survival with bladder conservation for patients with complete response was found in both subgroups of uniformly treated patients. A 17% incidence of severe late gastrointestinal tract complications was noted in the subgroup of patients treated with large radiation fractions. These results confirm the prognostic value of the tumor response at cystoscopy after radical radiotherapy, expand the total dose or TDF range over which it has been observed and document its occurrence with an unconventional radiation fractionation schedule.

Adult↗