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Biomedical subjects

R E Hunter

Publications and source records attributed to R E Hunter.

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

High-dose, short-duration cisplatin/doxorubicin combination chemotherapy for advanced ovarian epithelial cancer.

Sixty-one patients with epithelial ovarian cancer were treated with intensive high-dose, short-course chemotherapy that consisted of cisplatin (120 mg/m2) and doxorubicin (70 mg/m2) every 3 weeks for four cycles. Patients in complete clinical remission were offered second-look laparotomy (SLL). Patients with minimal or no residual disease at SLL were randomized to either cyclophosphamide (1000 mg/m2 every 21 days for six cycles) or whole-abdominal radiation therapy. All patients completed therapy with a median leukocyte nadir 1.3/microliter and platelet nadir of 90/microliters. Forty-five patients (74%) had a complete clinical response. Results of twenty-two of 36 second-look procedures (64%) showed no evidence of disease (NED). After SLL, 19 patients received six courses of cyclophosphamide and 16 patients received whole-abdominal radiation. Nine patient who refused SLL and one patient with negative SLL findings refused additional treatment. The median survival time for all patients was 51.3 months. High-dose intensive chemotherapy regimens have high response rates, but survival needs to be compared with traditional low-dose regimens. Although high-dose cisplatin and doxorubicin were myelosuppressive, the resulting complications were manageable. There was no significant difference between the mean survival times of patients receiving Cytoxan, abdominal radiation, or no treatment as second-line therapy.

Adult↗
PubMed1991

Adenoid cystic carcinoma of the vulva: a radiosensitive tumor.

A patient with adenoid cystic carcinoma of the vulva treated primarily with surgery developed multiple local and distant recurrences in which radiotherapy repeatedly achieved complete local control. The patient survived 11.5 years from original diagnosis and 9.5 years from primary recurrence before dying of pulmonary metastases. Adenoid cystic carcinoma of the vulva is a highly radiosensitive tumor. Adjuvant radiotherapy should be considered as a part of the primary therapy, to improve local control, on the basis of the much larger experience with adjuvant radiotherapy with this tumor in the head and neck. Also on the basis of head and neck tumors, it is unlikely that radiotherapy will affect survival.

Aged↗
PubMed1991

Appendectomy in primary and secondary staging operations for ovarian malignancy.

Appendectomy was performed at primary or secondary staging operations in 100 patients with ovarian malignancies. Of 80 patients who underwent appendectomy at the time of their primary surgery, 25 (31.2%) had appendiceal metastases. Among 47 patients who were believed to have disease limited to the pelvis at the time of surgery--stage I (N = 34), II (N = 7), IIIA (N = 5), and those designated stage IIIC solely on the basis of microscopic para-aortic nodal metastasis (N = 1)--the appendix was involved with disease in only two patients (4.3%). However, among 33 patients with advanced disease--stage IIIB (N = 6), IIIC except those designated IIIC solely on the basis of microscopic paraaortic nodal metastasis (N = 19), and IV (N = 8)--the appendix was involved with disease in 23 patients (69.7%) (P less than .001). Poorly differentiated tumors and serous histologic cell types more frequently metastasized to the appendix (64, 15, 6, and 8% for grades 3, 2, and 1 and borderline histology, respectively; P less than .001; and 48, 13, and 8% for serous, endometrioid, and mucinous; P less than .001). Of 20 patients who underwent appendectomy at their secondary staging procedure, two had metastases. Metastatic disease in the appendix was microscopic in nine of 27 patients. Because the frequency of appendiceal metastasis is similar to that of other metastatic sites in stages I and II ovarian cancer, it should be removed at primary staging procedures. Appendectomy should also be performed in patients with advanced ovarian malignancies if it contributes to cytoreduction or at the time of secondary staging procedures.

Appendectomy↗
PubMed1990

Factors affecting graft force in surgical reconstruction of the anterior cruciate ligament.

The effect of the maximum unloaded graft length (Lo) and femoral fixation hole location on graft force with the knee under anteriorly directed tibial loads was measured in five fresh cadaver knees with a reconstruction of the anterior cruciate ligament (ACL). The reconstruction was performed using a composite graft consisting of the semitendinosus and gracilis tendons augmented with the Kennedy ligament augmentation device (LAD). Buckle transducers were used to measure ligament and graft forces. The total graft force was adjusted to match the intact ACL at 30 degrees flexion using a force-setting method so that a standardized reference configuration could be repeatedly obtained. The graft force was highly sensitive to Lo, typically changing by 50% with a change in Lo of 3 mm. Variation in femoral hole location of 5 mm anterior, posterior, proximal, and distal to the anatomic position produced changes in graft force, particularly at 60 degrees and 90 degrees flexion; however, these changes were not statistically significant. The effect of femoral hole location varied considerably between knees. This variability makes predicting proper hole placement difficult, and suggests the need to adjust each knee at surgery to account for this variable femoral hole position sensitivity.

Adult↗
PubMed1990

Method for setting total graft force and load sharing in augmented ACL grafts.

The objective of this study was to develop a method for obtaining a controllable and reproducible immediate postoperative mechanical state in a knee with an anterior cruciate ligament (ACL) reconstruction. This method, called the force-setting technique, was demonstrated using a composite graft consisting of the middle third of the patellar tendon with bone blocks (PT) and the ligament augmentation device (LAD). The total graft force was set to match the force in the intact ACL at 30 degrees flexion with the knee under the same standardized external load, while at the same time the load sharing between the biologic and augmentation components was controlled. The total graft force was set to match the ACL force three separate times in each knee, with ratios of load sharing set at the following levels: 50% PT-50% LAD, 25% PT-75% LAD, and 75% PT-25% LAD. ACL, PT, LAD, and collateral forces were measured using buckle transducers, and three-dimensional knee motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to eight specimens at 0 degree, 30 degrees, 60 degrees, and 90 degrees flexion with an intact ACL, an excised ACL, and the three load-sharing reconstruction states. The total graft force could be consistently set to within an average of 2% of the intact ACL force at 30 degrees flexion, and load sharing between the graft segments could be set to within an average of 5.1% of the desired ratio at 30 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadaver↗
PubMed1990

Effects of uric acid and caffeine on A1 adenosine receptor binding in developing rat brain.

Previous studies have demonstrated that elevated levels of serum uric acid or caffeine are associated with increased locomotor activity in rats and humans. Since uric acid and caffeine are structurally similar, it was hypothesized that these compounds alter locomotor activity through a common neural mechanism, specifically by acting as receptor antagonists at adenosine A1 binding sites. In vitro competition of caffeine and uric acid against the A1 agonist, [3H] cyclohexyladenosine ([3H]CHA), was conducted using homogenates of adult rat forebrain. Caffeine effectively competed for the A1 binding site as previously reported (IC50 = 107 microM), but uric acid failed to compete with [3H]CHA binding at concentrations within a relevant physiological range. Nevertheless, in vivo experiments indicated that chronic elevation of uric acid following allantoxanamide treatment of male rats on days 4-27 of life significantly decreased A1 receptor binding in the striatum, a region traditionally implicated in mammalian locomotion. In contrast, chronic caffeine treatment on days 4-27 of life caused an increase in A1 receptor binding in the cortex similar to increases reported previously in whole brain. These changes in A1 receptor binding following chronic elevation of uric acid or caffeine did not persist in rats that had been withdrawn from allantoxanamide or caffeine treatment for 14 days. Results from in vitro and in vivo experiments indicate that despite a similar molecular structure uric acid does not act by the same mechanism as caffeine to increase locomotor activity in rats.

Adenosine↗
PubMed1990

Anterolateral rotatory instability of the knee. Cadaver study of extraarticular patellar-tendon transposition.

A cadaver knee-testing system was used to analyze the effect of an extraarticular reconstruction for anterolateral rotatory instability in which the lateral one third of the patellar tendon with a patellar bone block was transposed to the lateral femoral condyle. Ligament and reconstruction tendon forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage as 90 N anteriorly directed tibial loads were applied to seven knee specimens at 0 degree, 30 degrees, 60 degrees, and 90 degrees of flexion by a pneumatic load apparatus. This was done for each knee with first an intact, then an excised anterior cruciate ligament, and finally the extraarticular reconstruction. Forces in the transposed graft exhibited an isotonic pattern over the flexion range, unlike the intact anterior cruciate ligament, which was more highly loaded in extension than in flexion. The transposition of the patellar tendon led to external rotation of the tibia in both unloaded and anterior load conditions throughout flexion. Collateral ligament forces increased with anterior cruciate ligament excision, with the force in the medial ligament remaining higher than normal with the reconstruction, while the lateral forces became lower than normal.

Biomechanical Phenomena↗
PubMed1990

The anterior cruciate ligament.

Our knowledge of the anterior cruciate ligament has expanded rapidly over the last decade. Recent advances in arthroscopic techniques, the development and release of synthetic stents and prostheses, increasing laboratory and clinical data involving allograft implantation, and biomechanical research in knee rehabilitation have led to a bewildering array of choices for treatment of anterior cruciate ligament deficiency. As new information and techniques are presented, and new synthetic and biological materials become available, orthopedic surgeons must judge their value and modify treatment recommendations accordingly. A thorough knowledge of the basic science and clinical information is necessary to appropriately evaluate these new advances. A review of our current knowledge of the anterior cruciate ligament is presented to facilitate this evaluation process.

Biomechanical Phenomena↗
PubMed1990

Primary adenocarcinoma of the breast arising in the vulva.

Primary adenocarcinoma of ectopic breast tissue in the vulva has been reported in only four instances. A fifth case, in which estrogen and progesterone receptors were present, is described. Estrogen and progesterone receptor studies may be helpful in identifying adenocarcinoma of uncertain origin.

Adenocarcinoma↗
PubMed1990

Functional analysis of anterior cruciate ligament braces.

Whether or not anterior cruciate ligament (ACL) braces work has been the subject of some debate. Research efforts undertaken to understand these braces have been divided into two fronts: static and functional analysis. This article explores those issues surrounding the functional analysis of ACL braces.

Anterior Cruciate Ligament↗
PubMed1990

Prognostic significance of estrogen and progesterone receptors in epithelial ovarian cancer.

Estrogen and progesterone receptor assays were analyzed from epithelial ovarian cancer in 123 patients to determine the prognostic significance of receptor results. In 110 (89%), assays were performed at diagnosis and in 13, assays were performed after previous therapy. Estrogen receptor determinations were positive (above 10 fmol/mg) in 75 cases (61%), progesterone receptor determinations were positive (above 3 fmol/mg) in 35 (28%), and both were positive in 20 (16%). Progesterone receptors were more frequently positive (53%) in tumors of endometrioid histology than with other histologic types (P = .01). Thirty-one subjects had a second assay; estrogen receptors were positive in 16 cases (52%), progesterone receptors were positive in five (17%), and both were positive in five (17%). Synchronous and metachronous assays were in agreement in 60-79% of the cases. By multivariate analysis, positive estrogen receptor, progesterone receptor, or both did not predict response to chemotherapy, negative second-look findings, or survival. Thirty-one women received hormonal therapy; one of 26 evaluable subjects had a partial response and four (13%) maintained stable disease for at least 6 months (6-21 months). Positive receptors did not predict hormonal response or disease stabilization.

Adult↗
PubMed1989

Comparison of abdominopelvic computed tomography results and findings at second-look laparotomy in ovarian carcinoma patients.

In 35 women with epithelial carcinoma of the ovary, the results of restaging laparotomy were compared with the preoperative abdominopelvic computed tomography (CT) findings to evaluate the accuracy of CT for determining tumor status. In the 36 studies performed, enhanced CT scans at 10-mm to 15-mm intervals had a sensitivity of 84% and a specificity of 88%; in addition, there was 86% agreement between the CT and surgical findings. These results suggest that although CT is not accurate enough to completely replace the restaging laparotomy, its high accuracy in determining residual disease after treatment is helpful for patient management.

Adenocarcinoma↗
PubMed1989

Lymphoepithelioma of the uterine cervix.

A patient with a squamous cell carcinoma of the cervix with marked lymphocytic infiltration is reported and the literature reviewed. Although the entity has been rarely reported in the United States, the Japanese literature suggests that patients with this variant may have a more favorable prognosis.

Adult↗
PubMed1989

Hyperuricemia and locomotor activity in developing rats.

This research was motivated by the previous finding that serum uric acid levels correlate with symptoms of hyperactivity in normal children. We attempted, therefore, to investigate this relationship in an animal model. Dose and time relationships between allantoxanamide-induced heightened serum uric acid and locomotor activity were investigated. A dose- and time-dependent relationship was shown between serum uric acid levels and allantoxanamide. Those doses of allantoxanamide which elevated serum uric acid produced time-dependent changes in locomotor activity. In the first two hours following injection, activity increased relative to controls, in the next two-hour block activity decreased, only to rise again above control levels in the third two-hour period. The possible role of uric acid and allantoxanamide are discussed in relation to these complex changes in activity.

Animals↗
PubMed1989

Knee joint motion and ligament forces before and after ACL reconstruction.

The goal of this in vitro study was to investigate the initial postoperative mechanical state of the knee with various types of anterior cruciate ligament (ACL) reconstructions. An experimental knee testing system was developed for the in vitro measurement of ligament forces and three-dimensional joint motion as external loads were applied to fresh knee specimens. Two groups of knee specimens were tested. In test series #1, two intraarticular reconstructions were performed in each of five specimens using semifree and free patellar tendon grafts with bone blocks. In test series #2, a more carefully controlled intraarticular reconstruction was performed in five specimens using a semifree composite graft consisting of the semitendinosus and gracilis tendons augmented with the Ligament Augmentation Device. Ligament force and joint motion data were collected as anteriorly directed tibial loads were applied to the normal joint, the joint with a cut ACL and the reconstructed joint. These knee joint states were compared on the basis of ACL or graft forces, joint motion and load sharing by the collateral ligaments. The dominate result of the study was that the forces and motions defining the mechanical state of the knee after the ACL reconstructions in both test series were highly variable and abnormal when compared to the normal knee state. The higher level of surgical control series #2 did not decrease this variability. There was a poor correlation between motion of the reconstructed knee relative to normal, and the ACL graft force. There was little consistent difference in force and motion results between the surgical procedures tested.

Humans↗