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Biomedical subjects

S A Davidson

Publications and source records attributed to S A Davidson.

At least 19 recordsLinked to original sources
PubMed2001

Topotecan concomitant with primary brachytherapy radiation in patients with cervical carcinoma: a phase I trial.

OBJECTIVE: The aim of this study was to assess the toxicity of concomitant topotecan and radiation therapy in a Phase I study. Primary treatment for cervical carcinoma usually consists of surgery or radiation, with chemotherapy used in a neoadjuvant or concomitant fashion. There are in vitro data to suggest that topotecan is a radiosensitizing agent. METHODS: Six patients with cervical cancer were recruited to this study. All patients had completed whole pelvic radiation therapy and were scheduled for low-dose brachytherapy. The patients were administered topotecan IV during their low-dose brachytherapy. The initial dose of topotecan was 0.5 mg/m2/day for 5 days concomitant with low-dose brachytherapy for two brachytherapy applications. RESULTS: Three patients were accrued to the initial dose level. No major toxicity was noted at this dose level. Three patients were treated at the 1.0 mg/m2/day dose level; however, significant toxicity was noted at this level. (Two patients experienced grade 4 and one a grade 3 hematologic toxicity). CONCLUSION: Significant marrow toxicity was noted with concomitant topotecan and intracavitary radiation at 1.0 mg/m2/day. The maximum tolerated dose in this trial was 0.5 mg/m2/day for 5 days of topotecan concomitant with low-dose brachytherapy.

Adenocarcinoma↗
PubMed1997

Spontaneous arterial thrombosis with an advanced ovarian malignancy.

Arterial thromboembolic disease almost always occurs in the setting of significant cardiovascular disease. Fewer than 10% of patients have no known etiology and only rarely is malignancy implicated. A review of the literature revealed only one prior report associated with a gynecologic malignancy, and this occurred in the lower extremities in a postoperative setting. We report here the case of a woman with arterial occlusion of her left upper extremity who was subsequently diagnosed as having ovarian adenocarcinoma. Her dramatic response to chemotherapy is described, and the diagnosis and management of arterial occlusion is reviewed.

Adenocarcinoma↗
PubMed1997

Molar pregnancy in a 60-year-old woman.

Molar pregnancy has not been reported in women past the age of 57 in the English literature. This report reviews a 60-year-old woman who presented with irregular bleeding and was diagnosed as having a complete hydatidiform mole. The patient underwent hysterectomy and had spontaneous return of her human chorionic gonadotropin levels to normal. Diagnosis in this age group depends on a high level of suspicion, and hysterectomy should be considered due to the high risk of postmolar gestational trophoblastic tumor after suction uterine evacuation.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed1997

Increased nephrotoxicity of combination taxol and cisplatin chemotherapy in gynecologic cancers as compared to cisplatin alone.

To investigate the increased nephrotoxicity of taxol and cisplatin combination chemotherapy in gynecologic cancers as compared to cisplatin alone, the medical records of 25 patients with gynecological cancers were reviewed for evaluation of nephrotoxicity after chemotherapy treatment. The data included age, serum creatinine, calculated creatinine clearance, initial and cumulative dose of cisplatin and taxol, primary site of the cancer, renal ultrasound and hydration protocols. Renal function was evaluated before, during and 6 months after chemotherapy. Renal dysfunction was defined as a greater than 25% decrease in creatinine clearance. Comparing 11 patients treated with taxol and cisplatin versus 14 treated with cisplatin alone, there was a significant difference in effect on renal function. Nine of 11 patients (81%) treated with the combination chemotherapy had a greater than 25% decrease in creatinine clearance while only 4 of the 14 patients (29%) treated with cisplatin alone had such a decrease in creatinine clearance (p < 0.004). The patients treated with the combination chemotherapy, however, received a higher dose of cisplatin (80.4 vs. 66.4 mg/m2, p < 0.02) and were treated longer (6.7 vs. 4.3 months, p < 0.002). Nevertheless, when the patients were matched for age, initial dose and cumulative dose of cisplatin, a higher frequency of nephrotoxicity persisted in patients treated with taxol and cisplatin as compared to cisplatin alone (72 as compared to 20%, p < 0.02). The patients in both groups were comparably hydrated; prerenal failure and urinary tract obstruction were excluded in all patients. Six months after completion of chemotherapy, a significantly lower creatinine clearance was still observed in patients treated with taxol and cisplatin combination therapy (46 vs. 76 ml/min, p < 0.01). In summary, a retrospective analysis of renal function in patients with gynecological cancers showed an increased nephrotoxicity in patients treated with taxol and cisplatin as compared to cisplatin alone. A prospective study is therefore needed to examine the potential additive toxic effect of the combination of taxol and cisplatin on long-term renal function, including potential preventive interventions.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Preference for and performance with damped and undamped hearing aids by listeners with sensorineural hearing loss.

This study investigated the relationship between acoustic damping of hearing aid responses and listeners' speech discrimination and judgments of preference and sound quality. Eighteen subjects with essentially equivalent hearing impairments participated. Subjects' speech discrimination was evaluated for a male talker in quiet and in noise and for a female talker in the same conditions with hearing aids with 0 dB, -5 dB, and -10 dB of damping. Subjects also compared the damping levels using eight bipolar adjective pairs and provided judgments of overall preference. Measurements of the hearing aid responses were made in a 2-cm3 coupler and in the subjects' ears using probe microphone techniques. Smoothness of the responses was quantified using the Index of Response Irregularity (IRI) and the Frequency Response Smoothness Quantification Index (FReSQI). Subjects preferred the two damped hearing aid responses to the undamped. They also had better speech discrimination with damped hearing aid responses. The bipolar adjectives were of limited use in comparing hearing aids. A few questions about hearing aid sound quality and preference appear adequate for evaluating listeners' choice of hearing aids. Smoothness of the hearing aid responses in the test box was higher for the damped hearing aids than for the undamped. However, for real ear responses measured using a probe microphone, smoothness did not change as a function of damping level.

Acoustics↗
PubMed1996

Assistive listening devices and hearing aids: coupling considerations.

Assistive listening devices (ALDs) can be used to supplement hearing aid performance in difficult listening conditions, but caution must be used when coupling ALDs to personal hearing aids because the frequency-gain characteristics of the hearing aid may be altered. Data illustrating subject performance using ALDs coupled to personal hearing aids, ALDs with headsets, and ALDs coupled to hearing aids with programmable telecoils are presented to illustrate the problems associated with coupling ALDs and hearing aids and to provide possible solutions to these problems.

Correction of Hearing Impairment↗
PubMed1994

Dose escalation combination carboplatin/cyclophosphamide chemotherapy for epithelial ovarian cancer.

Dose intensification chemotherapy is currently under investigation in ovarian cancer. In order to establish an optimum dose for future colony stimulating factor trials, 16 patients with ovarian cancer were treated with dose-escalation combination carboplatin plus cyclophosphamide chemotherapy without growth factors. The initial carboplatin dose, 300 mg/m2, was increased to a maximum dose of 400 mg/m2. The initial cyclophosphamide dose, 600 mg/m2, was increased to a maximum dose of 1200 mg/m2. Of 10 patients completing 6 cycles, six patients (60%) were escalated to carboplatin 400 mg/m2 and cyclophosphamide 600-1200 mg/m2. Myelosuppression was severe, with all 6 patients requiring platelet and/or packed red blood cell transfusions. Based on these results, carboplatin 400 mg/m2 with cyclophosphamide 600 mg/m2 was selected as the starting dose with hematopoietic growth factors.

Adult↗
PubMed1993

Limited-field radiotherapy as salvage treatment of localized persistent or recurrent epithelial ovarian cancer.

Thirty-five patients with persistent or recurrent epithelial ovarian cancer were treated with salvage pelvic or para-aortic radiotherapy for disease limited to the pelvis (29), para-aortic retroperitoneum (5), or vaginal cuff (1). Prior therapy included a median of 3 chemotherapeutic drugs (range, 1-7) over a median of 12 cycles (range, 5-39); 12 patients had received intraperitoneal chemotherapy. The median number of prior laparotomies was 3 (range, 2-5). Including pelvic boosts, the median dose delivered to the treatment field was 4600 cGy (range 4000-7000); 2 patients received additional treatment with a permanent 125I implant. All patients completed therapy, although 5 (14%) with grade 3 toxicity required a treatment break. Late bowel complications unrelated to recurrence occurred in 3 patients (9%). Median actuarial and progression-free survivals for all patients from start of radiotherapy were 40 and 14 months, respectively. At least 16 of 26 (62%) recurrences involved the treatment field. Multiple prognostic factors were evaluated in terms of recurrence, survival, and acute and chronic complications, but no significant prognosticators were detected. These findings indicate that limited-field salvage radiotherapy has an acceptable complication rate and may prolong the symptom-free survival interval in selected patients.

Adult↗
PubMed1992

Lymph node sampling in patients with epithelial ovarian carcinoma.

Lymph node sampling is part of the FIGO staging of patients with ovarian carcinoma and is usually part of a meticulous second look operation. We analyzed the primary lymph node status of patients and compared this to the lymph node status at second look operation. From 3/86-3/91, 97 patients with epithelial ovarian tumors were treated at this institution. Seventy-one of the 97 patients (73.2%) had lymph node sampling at primary surgery. Thirty of the 71 patients had positive lymph nodes (42.2%) and 41 patients were lymph node negative (57.8%). Of the initial 97 patients, 58 were eligible for second look operation (59.8%), and 48 of these patients had lymph nodes sampled at second look operation. Nine of the 48 patients had positive lymph nodes (18.7%) and 39 had negative lymph nodes at second look operation (81.3%). Of the patients with negative lymph nodes at primary surgery, 25 patients had second look operation and 24 of these patients had lymph node sampling at second look operation. All patients with negative lymph nodes at primary surgery had negative lymph nodes at second look operation. Of the 30 patients with positive lymph nodes at primary surgery, 12 underwent second look operation. Four patients had persistent positive lymph nodes and 8 patients had negative lymph nodes. Our data suggest that patients with negative lymph nodes at primary surgery are unlikely to have positive lymph nodes at second look operation. Therefore, we believe that lymph node sampling under these circumstances is unnecessary.

Adolescent↗
PubMed1991

Intraperitoneal chemotherapy: analysis of complications with an implanted subcutaneous port and catheter system.

To determine the morbidity associated with delivery of intraperitoneal chemotherapy via subcutaneous semipermanent infusion catheters, we analyzed the data on 227 patients treated from April 1985 through December 1989. A total of 249 catheters were inserted and used to administer chemotherapy in these patients. There were 40 (17.6%) complications associated with the use of 230 original catheters, with 20 patients experiencing catheter inflow obstruction and 20 developing catheter-related infections; the latter group included 8 patients with bowel perforations. Although there was a trend toward an increase in catheter-related infections in association with large bowel surgery and appendectomies, sample size limited statistical analysis. There were 7 (36.8%) complications associated with the use of 19 replacement catheters. This rate was significantly increased (P = 0.03) when compared with the complication rate of original catheters. This system functions well and has an acceptable level of morbidity for delivery of intraperitoneal chemotherapy in gynecologic cancer patients.

Catheterization↗
PubMed1991

Determining latency and amplitude for multiple peaked P300 waveforms.

The P300 is characterized by a large positive peak occurring approximately 300 msec post stimulus onset. When a single peak is present, the P300 latency is easily identifiable. However, in cases where the P300 waveform is broadly or multiply peaked, ambiguity exists when attempting to determine the latency of the waveform. Amplitude, while less ambiguous, has also been variously measured as baseline to peak, or peak-to-peak, using either N200 or N300 as the trough. The present study was undertaken to evaluate a method for precisely and consistently determining the latency and amplitude characteristics of the P300 waveform. Three independent raters examined 40 records to determine P300 latency and amplitude according to prescribed criteria. Results indicated that the suggested techniques yield good inter-rater agreement on the latency and amplitude characteristics of the P300 waveform regardless of P300 morphology.

Adult↗
PubMed1990

Preliminary studies on the use of an ABR amplitude projection procedure for hearing aid selection.

Hearing aid selection in young nonverbal children is difficult and objective selection procedures are needed. Kiessling (Scand Audiol 1982;11:269-275; Arch Otorhinolaryngol 1983;238:233-240) has proposed an objective hearing aid selection method based on an unaided ABR amplitude projection procedure. However, Kiessling's ABR projection method is based on the assumption that ABR amplitude is directly related to the loudness of a signal--an assumption which has not been tested. This assumption was investigated in a group of ten normally hearing and three hearing-impaired listeners. The results indicated that ABR amplitude measures obtained in a single trial do not always correlate well with perceived loudness, but ABR amplitudes averaged over several trials do correlate well with estimates of perceived loudness. The hearing-impaired listeners then participated in a second phase of the investigation in which hearing aids chosen by the ABR projection procedure were compared with hearing aids chosen by more conventional methods. The results indicated that the projection procedure prescribed appropriate gain and compression characteristics for two of the three hearing-impaired listeners.

Adult↗
PubMed1990

Reclosure of disrupted abdominal incisions.

We evaluated prospectively a technique of delayed reclosure of disrupted abdominal incisions. Forty-one consecutive postoperative obstetric and gynecologic patients with abdominal incisions that had opened because of infection, hematoma, or seroma and had intact fascia participated in the study. All wounds were first managed identically, with surgical drainage and debridement, for a minimum of 4 days. The patients then were randomized to either wound reclosure by a standardized en bloc technique (35) or healing by second intention (six). Reclosure was successful in 30 of 35 cases (85.7%). The mean time to complete healing was 15.8 days in successful cases, 67.2 days in failed cases, and 23.2 days for all patients who were reclosed. Failure to heal after reclosure was due to subcutaneous infection in two patients and seroma in three; these women were significantly heavier than those in whom reclosure was successful. There were no other major complications of wound reclosure. Patients randomized to healing by second intention required a mean of 71.8 days of wound care. The time to complete healing in the wound-reclosure group was significantly shorter compared with the group that healed by second intention (P = .002, log rank test). We conclude that en bloc reclosure of disrupted surgical incisions, compared with nonsurgical treatment, significantly decreases the time required for wound healing and has minimal morbidity.

Adult↗
PubMed1990

Treatment failure in endometrial carcinoma.

Endometrial carcinoma has been regarded as one of the more curable gynecologic malignancies. Clinical stage, grade, and depth of myometrial invasion are well-established prognostic variables. We examined the clinical course of 520 patients with endometrial carcinoma treated at Walter Reed Army Medical Center and the Naval Hospital, Bethesda, Maryland, between January 1, 1960 and December 31, 1982. Life table 5-year survivals for stages Ia, Ib, II, III, and IV were 89, 92, 77, 27, and 0%, respectively. Compared with patients with grade 1 endometrial adenocarcinomas, significant decreases in survival were noted for patients with grade 2 or 3 endometrial, papillary endometrioid, serous papillary, and clear-cell tumors. There were six treatment-related deaths (1.2%). Thirty-eight patients (7.3%) developed recurrent disease, with a median time to recurrence of 15 months and a median survival of 21 months. Two of 11 patients with pelvic recurrence were salvaged by radiotherapy, whereas none of 27 patients with distant failure survived. Sixteen advanced-stage patients (3.1%) with persistent disease had a median survival of 4.5 months. Patients with advanced disease or unfavorable histologic subtypes responded poorly to conventional therapy. Current salvage treatments are largely ineffective. Combined-modality therapy and systemic adjuvant therapy should be prospectively evaluated in high-risk patient subgroups.

Adenocarcinoma↗
PubMed1989

Presentation level determination for CV tokens using a computer-controlled adaptive procedure.

The feasibility of using a computer-controlled adaptive procedure to find maximum monotic performance for consonant-vowel (CV) stimuli was evaluated and compared to the procedure typically used to determine a performance-intensity function in two experiments. In experiment I, the computer-controlled adaptive procedure and the typical manual procedure were evaluated on 26 normally hearing listeners. Results indicated that the shape of the performance-intensity functions was similar for both procedures with the computer-controlled adaptive procedure selecting a higher presentation level. The test-retest reliability for the computer-controlled adaptive procedure was good with a mean difference on retest of 1.2 dB. In experiment II, the same procedures were evaluated using 9 sensorineural hearing impaired subjects. Again similar configuration between functions was observed. The primary advantage of the computer-controlled adaptive procedure for both subject groups is efficiency in terms of time of administration and number of CV stimuli used.

Adolescent↗