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D E Powell

Publications and source records attributed to D E Powell.

At least 19 recordsLinked to original sources
PubMed1994

Different signaling pathways for CD18-mediated adhesion and Fc-mediated phagocytosis. Response of neutrophils to LPS.

The regulation of CD11b/CD18 adhesive and phagocytic functions on human polymorphonuclear leukocytes (PMN) in response to LPS was examined. Adhesion of PMN to surfaces coated with LPS had little or no effect on the cells, but pretreating the LPS-coated surfaces with either diluted serum or LPS-binding protein strongly enhanced their ability to bind C3bi-coated E (EC3bi), a ligand for CD11b/CD18. LPS-binding protein is known to enable responses of cells to LPS by facilitating binding of LPS to CD14. Consistent with this, we found that preformed complexes of LPS with soluble rCD14 stimulated binding of ligand by CD11b/CD18 in a concentration-dependent manner. Known agonists that stimulate CD11b/CD18 binding activity on PMN all cause simultaneous enhancement of Fc-mediated phagocytosis. However, LPS presented in complex with either serum proteins or CD14 failed to stimulate the ingestion of ElgG by PMN. The number of FcRs and their ability to bind ligand were not affected by treatment with LPS, nor were they compromised in their ability to respond to other agonists. These results suggest that LPS generates intracellular signals that alter the ability of CD11b/CD18 to bind ligand, but this alteration is not sufficient to promote phagocytosis of IgG-coated particle. This conclusion was confirmed by showing that PMN treated with LPS and serum produced a lipid with the properties of integrin-modulating factor 1: acetone extracts of these cells stimulated CD11b/CD18 adhesive capacity on PMN. However, the lipid did not enhance Fc-mediated phagocytosis. These studies suggest that CD14 affects CD11b/CD18 function by inducing the synthesis of a lipid such as IMF-1, and that this lipid affects only the binding activity, not the phagocytosis-promoting capacity of CD11b/CD18.

Antigens, CD↗
PubMed1992

Resistance to tamoxifen with persisting sensitivity to estrogen: possible mediation by excessive antiestrogen binding site activity.

The growth of a large proportion of estrogen receptor-positive breast tumors is stimulated by estrogen and can often be controlled through antiestrogen therapy. Resistance to antiestrogen (AE) therapy can occur while tumors retain the expression of estrogen receptors (ERc) and remain functionally responsive to estrogens. The ability of specific antiestrogen binding sites (AEBS) to prevent AE from interacting with ERc has been examined as a possible mechanism through which this appropriation of AE could interfere with antiestrogen action. Comparisons were performed between uterine preparations where ERc activity exceeded AEBS binding and liver preparations where AEBS binding predominated. Identical estimates of ERc activity were obtained in uterine preparations using either [3H]estradiol or [3H]-4OH-tamoxifen and radioinert diethylstilbestrol (alpha,alpha'-diethyl-4,4'-stilbenediol) to estimate nonspecific binding. AEBS binding was observed only when [3H]-4OH-tamoxifen was used, while binding to Type II sites was resolved only with [3H]estradiol. When excess AEBS activity predominated, analyses with radiolabeled estrogen and antiestrogen present simultaneously showed that virtually all of the antagonist was bound to AEBS with little of the antagonist available to associate with ERc. In an effort to relate these observations to AE resistance per se, ERc and AEBS were measured in MCF-7 human breast cancer cells (ERc-positive, responsive to estrogens and antiestrogens) and in variant AE-insensitive LY-2 human breast cancer cells (ERc-positive, responsive only to estrogens). In AE-resistant LY-2 cells, the ratio of AEBS:ERc was approximately three times greater than in MCF-7 cells. Examination of 128 human breast carcinomas revealed that AEBS activity was present and could exceed ERc activity. Importantly, the partition of significant AE away from ERc was observed in human specimens. These observations identify a biochemical mechanism for antiestrogen resistance through which AE access to ERc can be totally incapacitated while sensitivity to estrogens continues. These observations indicate that AEBS activity, in addition to ERc activity, may provide helpful information for predicting the response of certain cancers to hormonal therapy.

Animals↗
PubMed1992

Transition from benign to malignant epithelium in mucinous and serous ovarian cystadenocarcinoma.

The slides of all patients with ovarian cystadenocarcinoma treated at the University of Kentucky Medical Center from 1966-1990 were reviewed. Fifty-four serous tumors and 42 mucinous neoplasms were identified for further study. Benign epithelium adjacent to an area of borderline or malignant epithelium was observed in 74 tumors (79%) and a site of epithelial transition was noted in 38 cases (40%). The presence of associated benign epithelium was more common in borderline or well-differentiated lesions and in patients with early-stage disease. These findings are consistent with epidemiologic and molecular genetic data and suggest that certain benign serous or mucinous ovarian tumors have the potential for malignant transformation. Removal of these tumors, particularly in postmenopausal women, should result in a subsequent reduction in the frequency of ovarian cancer.

Adolescent↗
PubMed1992

Endometrioid carcinoma of the ovary and endometriosis: the association in postmenopausal women.

Histologic material from 42 patients with endometrioid carcinomas of the ovary was reviewed. Ovarian endometriosis was present in 11 cases (26%) and 8 of these patients were postmenopausal. The exact site of transition from benign to malignant epithelium was observed in 4 cases. The clinical characteristics of patients with associated endometriosis were not significantly different from those without this finding except that endometriosis was present only in patients with Grade 1 or Grade 2 carcinomas. These data suggest that ovarian endometriosis in the postmenopausal patient has the potential to undergo malignant transformation and, when detected, should be removed surgically.

Adenocarcinoma↗
PubMed1992

Molecular genetic changes in human epithelial ovarian malignancies.

The frequent finding of loss of heterozygosity (LOH) for a specific chromosomal marker in tumor DNA compared to normal DNA suggests the presence of a closely linked tumor-suppressor gene. Using Southern blot analysis, 34 primary ovarian epithelial tumors were examined for the presence of tumor-specific allelic losses, using six probes for chromosomes 6q, 11p, 13q, 16q, and 17p. A high incidence of LOH was observed on 11p, 13q, and 17p. LOH for 17p was present in 3 of 4 (75%) informative benign ovarian tumors, 1 of 5 (20%) borderline tumors, and 16 of 24 (67%) invasive ovarian cancers. Allelic loss with the H-ras1 probe on 11p was present in 10 of 19 (53%) invasive tumors but was not identified in 6 benign or borderline tumors. LOH on 13q was present in 18 of 31 (58%) informative cases including 8 of 10 (80%) Stage 1 tumors. This preliminary study suggests that loss of tumor-suppressor genes on chromosomes 13q and 17p may be early events in ovarian tumorigenesis and that changes on chromosome 11p are later events.

Alleles↗
PubMed1991

Differential effects of neutrophil-activating peptide 1/IL-8 and its homologues on leukocyte adhesion and phagocytosis.

Several structural homologues of the chemotactic peptide neutrophil-activating peptide 1/IL-8 (NAP-1/IL-8) were tested for their ability to influence the expression and function of adhesion-promoting receptors on human polymorphonuclear leukocytes (PMN). NAP-2, melanoma growth stimulatory activity, and two forms of NAP-1/IL-8 (ser-NAP-1/IL-8 and ala-NAP-1/IL-8, consisting of 72 and 77 amino acids, respectively), each caused an increase in the expression of CD11b/CD18 (CR3) and CR1, which was accompanied by a decrease in the expression of leukocyte adhesion molecule-1 (LAM-1, LECAM-1). The binding activity of CD11b/CD18 was also enhanced 3- to 10-fold by these peptides, but enhanced function was transient: binding of erythrocytes coated with C3bi reached a maximum by 30 min and declined thereafter. Ser-NAP-1/IL-8, ala-NAP-1/IL-8, NAP-2, and melanoma growth stimulatory activity also caused a two- to threefold enhancement of the phagocytosis of IgG-coated erythrocytes (EIgG) by PMN without causing a large increase in the expression of Fc gamma receptors. Enhanced phagocytosis of EIgG appeared to be mediated through CD11b/CD18, because F(ab')2 fragments of an antibody directed against CD18 inhibited NAP-1/IL-8-stimulated ingestion of EIgG. The four active peptides caused a rapid, transient increase in the amount of F-actin within PMN, indicating that they are capable of influencing the structure of the microfilamentous cytoskeleton, which participates in phagocytosis. Two other NAP-1/IL-8-related peptides, platelet factor 4 and connective tissue-activating peptide III, were without effect on expression of CD11b/CD18, CR1, and LAM-1, binding activity of CD11b/CD18, or Fc-mediated phagocytosis, and increased actin polymerization only slightly. Our observations indicate that several members of the NAP-1/IL-8 family of peptides were capable of promoting integrin-mediated adhesion and Fc-mediated phagocytosis, processes important in the recruitment of PMN to sites of inflammation and antimicrobial responses of PMN.

Actins↗
PubMed1991

Preoperative radiation therapy followed by extrafascial hysterectomy in patients with stage II endometrial carcinoma.

Seventy-four patients with Stage II endometrial cancer were treated by a combination of preoperative radiation therapy followed by extrafascial hysterectomy, bilateral salpingo-oophorectomy, and paraaortic lymph node sampling at the University of Kentucky Medical Center from 1967 to 1988. All patients had histologically confirmed endometrial cancer with involvement of the endocervix. The cell types and numbers of the tumors treated were as follows: adenocarcinoma, 58; adenoacanthoma, six; adenosquamous carcinoma, nine; and clear cell carcinoma, one. Preoperative radiation consisted of 4500 cGy external therapy followed by one intracavitary implant providing an additional 2000 cGy to point A. Surgery was done 4 to 6 weeks after completion of radiation therapy. Five patients (7.1%) had paraaortic lymph node metastases. Four were treated with extended-field radiation therapy and one with platinum-based combination chemotherapy. After treatment, the patients were followed at regular intervals from 2 to 22 years (mean, 5.4 years). Eleven patients (15%) had recurrent cancer, with the vagina and upper abdomen being the most common sites of spread. The estimated 5-year and 10-year disease-free survival rates of these patients are 88% and 76%, respectively. Cell type, depth of myometrial invasion, and lymph node status were the most important prognostic variables in the patients evaluated. These data confirm that the combination of preoperative radiation therapy and surgery produces excellent long-term survival in patients with Stage II endometrial cancer.

Adenocarcinoma↗
PubMed1991

Ovarian cancer screening in asymptomatic postmenopausal women by transvaginal sonography.

From November 1987 to January 1991, 1300 postmenopausal women underwent screening with transvaginal sonography (TVS). Women eligible for screening were all asymptomatic with no known ovarian tumors. Ovarian volume was calculated using the prolate ellipsoid formula, and a value in excess of 8.0 cm3 was considered abnormal. Ovarian abnormalities were detected in 33 women (2.5%), and 27 underwent exploratory laparotomy. Ovarian tumors were noted in all 27 patients, including 2 primary carcinomas and 14 serous cystadenomas. The two women with ovarian carcinomas had normal results of pelvic examinations and normal serum CA-125 levels. Both women had Stage I disease, and are alive and well after conventional therapy. TVS was time efficient, easy to perform, and well-accepted by patients. Currently, there are more than 3000 patient years of follow-up in the screened population, and there have been no deaths due to ovarian cancer. A multi-institutional trial to determine the efficacy of TVS as a screening method for ovarian cancer is indicated.

Adenocarcinoma↗
PubMed1990

Transvaginal sonography as a screening method for ovarian cancer. A report of the first 1000 cases screened.

From November 1987 to April 1989, 1000 women 40 years or older underwent screening vaginal sonography at the University of Kentucky Medical Center (Lexington, KY). Patients included in this investigation were all asymptomatic and had no known pelvic abnormalities. Each ovary was measured in three planes and ovarian volume was calculated using the prolate ellipsoid formula. The upper limit of normal for ovarian volume was 18 cm3 in premenopausal women and 8 cm3 in postmenopausal women. In patients with normal scans, mean ovarian volumes decreased from 6.8 cm3 to 3.0 cm3 with menopause. Thirty-one patients (3.1%) had abnormal vaginal sonograms and 24 underwent exploratory laparotomy. All patients undergoing surgery had ovarian or fallopian tube tumors with dimensions identical to those predicted by ultrasound. Histologic diagnoses of these tumors included the following: adenocarcinoma, one, serous cystadenoma, eight; endometrioma, six; and cystic teratomas, two. Vaginal sonography was performed easily and without complications, and was well accepted by patients. All patients with normal sonograms have been rescreened annually and none have subsequently developed ovarian cancer. Further clinical trials to determine the efficacy of vaginal sonography as a screening method for ovarian cancer are indicated.

Adult↗
PubMed1990

Chromosome abnormalities in human epithelial ovarian malignancies.

Karyotypic analysis of tumor specimens from 29 patients with untreated epithelial ovarian carcinoma was performed at the University of Kentucky Medical Center. Twenty-three of the twenty-nine tumors had adequate cells for analysis. Seventeen of these tumors exhibited chromosome abnormalities. Chromosome alterations were complex, with an average of seven different abnormal chromosomal patterns per tumor (range 2-14). Chromosomes 1 and 11 were the most commonly involved, being abnormal in 89 and 83% of tumors, respectively. Chromosomes 3 and 7 were also frequently abnormal. In contrast to invasive tumors, alterations in chromosomes 1 and 11 were not seen in the two tumors of borderline malignant potential. Evidence for DNA amplification of IGF2, Ha-ras-1, and c-ets was not observed. Amplification of the c-erbB-2 oncogene was present in two tumors. These findings indicate that multiple karyotypic abnormalities occur in untreated epithelial ovarian malignancies, with chromosomes 1 and 11 being the most frequently abnormal. These data also suggest that alterations of these chromosomes may be associated with the biologically aggressive behavior of frankly invasive ovarian tumors.

Adult↗
PubMed1990

Localization of prostaglandin endoperoxide synthase in the human corpus luteum.

Prostaglandins have been implicated in both maintenance and luteolysis of the primate corpus luteum. Central to the production of prostaglandins is the enzyme prostaglandin endoperoxide synthase (PGHS). In the present study, we identified the cell types which contain PGHS in 44 human corpora lutea, using immunoperoxidase staining techniques. Intense granular staining was present in the cytoplasm of granulosa lutein cells of tissues obtained from the mid-luteal phase. Theca lutein cells demonstrated a diffuse cytoplasmic staining which was less intense than that observed in granulosa lutein cells. Staining appeared less intense in tissues from the early or late phase. Ovarian stromal cells demonstrated little or no PGHS immunoreactivity. PGHS staining in the corpus luteum of pregnancy was similar in intensity and cell distribution to that of mid-luteal corpus luteum. In summary, human corpus luteum contains immunoreactive PGHS which localized mainly to well-differentiated granulosa lutein cells.

Adolescent↗
PubMed1989

Adjuvant oral alkylating chemotherapy in patients with stage I epithelial ovarian cancer.

From November 1973 to May 1986, 50 patients with Stage I epithelial ovarian cancer were treated at the University of Kentucky Medical Center (Lexington, KY) with oral Alkeran (melphalan) chemotherapy after primary surgery. Twenty-two patients had Grade 1 tumors, 23 patients had Grade 2 tumors, and five patients had Grade 3 tumors. Patients with ovarian tumors of borderline malignancy were excluded from this study. Twenty-eight patients received from six to 11 courses of chemotherapy and 22 patients completed 12 courses of chemotherapy. Chemotherapy was well tolerated and no patient died of chemotherapy-related complications. Thirty-eight patients underwent second-look laparotomy died of disease 41 months after diagnosis and one patient died with no evidence of disease 6 months after treatment. The actuarial survival of the total group of patients was 98% at 2 years and 94% at 5 years. Fewer than 12 months of chemotherapy may be necessary to obtain long-term survival in these patients.

Adenocarcinoma↗
PubMed1988

Small cell carcinoma of the uterine cervix.

From 1962 to 1985, 2201 patients with invasive cervical cancer were staged, evaluated, and treated at the University of Kentucky Medical Center. After a thorough evaluation, 25 cases (1.1%) fulfilled the histologic criteria for small cell cancer defined by Reagan and coworkers. These patients were computer-matched for age, disease stage, and lesion size to 25 patients with large cell nonkeratinizing cancer and 25 patients with keratinizing squamous cell cancer. Morphometric analyses of nuclear size and maximum nuclear diameter were performed on all cases without knowledge of cell type. Small cell cancers were characterized by a nuclear area of 160 mu 2 or less and a maximum nuclear diameter of 16.2 mu, which was significantly lower than that for large cell tumors. Thirty-three percent of the small cell carcinomas stained positively for the neuroendocrine markers (neuron-specific enolase [NSE] and chromogranin [CGR]), whereas the remainder contained only epithelial markers such as cytokeratin (CYK) and epithelial membrane antigen (EMA). Small cell cancers were associated with a high frequency of lymph-vascular space invasion and a diminished lymphoplasmacytic response. Patients with small cell cancer had a significantly higher recurrence rate, particularly to extrapelvic sites, than the matched patients with large cell cancers, and their survival was lower. Clinical trials to determine the efficacy of adjuvant chemotherapy in the treatment of small cell cervical cancer are needed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Ovarian dysgerminoma: report of seven cases and review of the literature.

Seven cases of ovarian dysgerminoma are presented and the recent literature reviewed. The majority of the cases reviewed had tumor confined to one ovary at the time of diagnosis, and nearly 50% occurred in women less than 20 years of age. The 5-year survival rate was 91% for 211 patients with stage I disease and 65% for 60 patients with stage II to IV dysgerminoma. The addition of contralateral adnexectomy, abdominal hysterectomy, and radiation therapy was not beneficial when disease was confined to one ovary. The survival of patients with advanced disease treated with chemotherapy was comparable with that of patients who received radiation. Analysis of the present data suggests that the use of unilateral oophorectomy should be limited to those patients with disease confined to one ovary and no histologic evidence of lymph node metastasis. Abdominal hysterectomy, bilateral adnexectomy, and adjuvant radiation is currently the treatment of choice for patients with more advanced dysgerminoma.

Adolescent↗