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Biomedical subjects

W E Thompson

Publications and source records attributed to W E Thompson.

At least 19 recordsLinked to original sources
PubMed2005

Reproductive cytotoxicity is predicted by magnetic resonance microscopy and confirmed by ubiquitin-proteasome immunohistochemistry in a theophylline-induced model of rat testicular and epididymal toxicity.

This study investigated the testicular changes in the rat induced by the nonspecific phosphodiesterase inhibitor, theophylline using magnetic resonance microscopy (MRM) and ubiquitin immunostaining techniques. In vivo T1- and T2-weighted images were acquired at 2 T under anesthesia. Increased signal observed in the theophylline-treated rats suggests that leakage of MRM contrast was occurring. In vivo MRM results indicate that day 16 testis displayed an increased T1-weighted water signal in the area of the seminiferous tubule that decreased by day 32. These findings were validated by histopathology, suggesting that in vivo MRM has the sensitivity to predict changes in testis and epididymal tissues. The participation of the ubiquitin system was investigated, using probes for various markers of the ubiquitin-proteasome pathway. MRM can be used to detect subtle changes in the vascular perfusion of organ systems, and the up-regulation/mobilization of ubiquitin-proteasome pathway may be one of the mechanisms used in theophylline-treated epididymis to remove damaged cells before storage in the cauda epididymis. The combined use of in vivo MRM and subsequent tissue or seminal analysis for the presence of ubiquitin in longitudinal studies may become an important biomarker for assessing testis toxicities drug studies.

Animals↗
PubMed2001

Characterization of prohibitin in a newly established rat ovarian granulosa cell line.

Prohibitin is an evolutionary conserved protein that is associated with cellular differentiation, atresia, and luteolysis in the rat ovary. However, the specific cellular location and function of prohibitin in ovarian cells has not been clearly elucidated. To characterize the expression of prohibitin during cell proliferation, differentiation, and cell death, we have successfully established a temperature-sensitive granulosa cell line, designated RGA-1. At a permissive temperature of 33 C, RGA-1 cells proliferate, but revert to a differentiated phenotype at a nonpermissive temperature of 39 C. Significant inductions of prohibitin mRNA and protein expression were observed in the differentiated phenotype when compared with proliferating cells. Differentiated RGA-1 cells were found to express inhibin alpha- and beta-transcripts, as well as steroidogenic acute regulatory protein and peripheral-type benzodiazepine receptor proteins in a manner reminiscent of steroidogenic functional responses observed in primary differentiated granulosa cells. Prohibitin expression correlated well with the expression of these steroidogenic proteins. At 39 C, RGA-1 cells also displayed increases in p53 protein levels, indicative of growth arrest in the nonproliferating cells. Confocal and electron microscopic examinations revealed increased prohibitin localization to the mitochondria at 39 C, along with changes in mitochondrial size and shape. These changes were accompanied by marked reductions in cytochrome c oxidase subunit II levels and in unit mitochondrial transmembrane potential. In addition, cell fractionation studies demonstrated that the prohibitin protein was mainly localized to the mitochondrial membrane. Collectively, these findings suggest a role for prohibitin in mitochondrial structure and function during growth and differentiation in ovarian granulosa cells. Prohibitin expression may also be indicative of mitochondrial destabilization during apoptosis-related events.

Animals↗
PubMed2001

A putative, ubiquitin-dependent mechanism for the recognition and elimination of defective spermatozoa in the mammalian epididymis.

The normal structure and function of sperm are prerequisites for successful fertilization and embryonic development, but little is known about how defective sperm are eliminated during mammalian spermatogenesis. Here, we describe a ubiquitin-dependent, sperm quality control mechanism that resides in the mammalian epididymis, the site of sperm maturation and storage. We used immunofluorescence, electron microscopy, western blotting and pulse-chase experiments to show that ubiquitin is secreted by the epididymal epithelium and binds to the surface of defective sperm. Most of the ubiquitinated sperm are subsequently phagocytosed by the epididymal epithelial cells. A portion of defective sperm escapes phagocytosis and can be found in the ejaculate. Cultured epididymal cells maintain their ability to produce ubiquitin and phagocytose the defective sperm, as well as the ubiquitin-coated microspheres, in vitro. The surprising phenomenon of cell-surface ubiquitination in defective sperm provides a possible mechanism for sperm quality control in mammals and a new marker of semen abnormalities in men and animals.

Animals↗
PubMed2001

Note on Thorson and Powell: undertakers' sense of humor.

Recently Thorson and Powell reported in this journal that morticians scored significantly lower on a multidimensional sense of humor scale than another group of similarly aged men from other occupations. These findings differ markedly with some in 1991 from a 2-yr. ethnographic study conducted with morticians and funeral directors in four states regarding how they managed the stigma associated with their occupation.

Adult↗
PubMed1999

Immunolocalization and expression of prohibitin, a mitochondrial associated protein within the rat ovaries.

This study was designed to determine the cellular distribution and pattern of expression for the mitochondria-associated protein, prohibitin, during the transitional stages of follicular differentiation within the rat ovary. Immunohistochemical staining techniques were used on frozen sections to examine the localization of prohibitin to preantral, antral, preovulatory, and atretic follicles. Prohibitin localization was also determined in corpus luteum from adult rats, in addition to those from infant and juvenile ovaries, before and after gonadotropin stimulation. Western and Northern blotting techniques were used for qualitative and quantitative assessment of prohibitin expression levels within the ovary. Prohibitin was localized within granulosa cells of infant and juvenile ovaries in a relatively heterogeneous staining pattern. The oocyte also exhibited robust prohibitin expression at all stages of follicular development. In addition, strong prohibitin expression was evident in the corpus luteum as well as in follicles undergoing atresia. Additional data derived from studies involving a GnRH-agonist indicate that increases in prohibitin protein expression correlate with the initial events of apoptosis. Collectively, these results support a growth regulatory role for prohibitin within the rat ovary. Therefore, we propose that prohibitin may serve as an important regulator of granulosa cell fate during follicular development.

Animals↗
PubMed1999

Immunolocalization and expression of the steroidogenic acute regulatory protein during the transitional stages of rat follicular differentiation.

This study was designed to determine the pattern of expression and cellular distribution of the steroidogenic acute regulatory protein (StAR) during the transitional stages of follicular differentiation in rat ovary. Using specific antisera against the StAR, immunohistochemistry, Western blotting, and immunoprecipitation analyses provide evidence confirming the localization and expression of StAR in granulosa cells (GCs) of juvenile rat ovaries before and after PMSG treatment. The results also show that StAR expression occurs in theca intersitial cells surrounding preantral, antral, and larger antral follicles in adult diestrous ovaries. Furthermore, we have demonstrated heterogenous StAR immunoreactivity in the granulosa cell layers and cells of the corpora lutea. A novel finding presented here is that, during ongoing growth and differentiation of the follicle, the immunoreactivity of StAR tends to shift from the GC of early antral follicles to the theca cell layers in the adult. The spatiotemporal changes or shifts in StAR expression and cellular localization also coincide with the appearance of more acidic isoforms of the 30-kD protein, as determined by two-dimensional gel electrophoresis. Although the functional implications of these observations remain unclear, the acute temporal changes in StAR expression and localization may not only reflect the dynamic steroidogenic capacity of follicular cells but may also support a possible role for FSH in the induction of follicular maturation.

Animals↗
PubMed1998

Proliferative and cytokine responses to class II HER-2/neu-associated peptides in breast cancer patients.

Previous studies have characterized the reactivity of CD8+ CTLs with ovarian and breast cancer. There is little information about the antigens and epitopes recognized by CD4+ T cells in these patients. In this study, we analyzed the ability of T cells from peripheral blood mononuclear cells of breast cancer patients to recognize HER-2/neu (HER-2) peptides. We found that 13 of 18 patients responded by proliferation to at least one of the HER-2 peptides tested. Of these peptides, one designated G89 (HER-2: 777-789) was recognized by T cells from 10 patients. Seven of nine responding patients were HLA-DR4+, suggesting that this peptide is recognized preferentially in association with HLA-DR4. Analysis of the specificity and restriction of the cytokine responses to G89 by G89-stimulated T cells revealed that these cells secreted significantly higher levels of IFN-gamma than interleukin 4 and interleukin 10, suggesting priming for a Th0-T helper 1 response. The same pattern of cytokine responses was observed to the intracellular domain of HER-2 protein, suggesting that G89-stimulated T cells recognized epitopes of the HER-2 protein in association with HLA-DR4. Because HLA-DR4 is present in 25% of humans, characterization of MHC class II-restricted epitopes inducing Th0-T helper 1 responses may provide a basis for the development of multivalent HER-2-based vaccines against breast and ovarian cancer.

Amino Acid Sequence↗
PubMed1997

Steroidogenic acute regulatory (StAR) protein (p25) and prohibitin (p28) from cultured rat ovarian granulosa cells.

This study has identified and characterized two intracellular proteins (25 and 28 kDa) during ongoing differentiation of rat granulosa cells isolated from preantral and early antral follicles. The identity of p25 was confirmed as the mitochondria associated StAR protein by western blotting analysis. In the culture conditions used, this protein was expressed only when granulosa cells were stimulated with FSH to produce progesterone. It is apparent that the steroidogenic differentiation of granulosa cells affects StAR expression. Amino acid sequence analysis of p28 identified it as prohibitin and was corroborated by western blot analysis with antibodies specific for rat prohibitin. During the ongoing differentiation of granulosa cells there were changes in the expression of p28/prohibitin. Although prohibitin is constitutively expressed in granulosa cells, there is an increase in the more acidic isoform of prohibitin when oestrogen concentrations are raised by increased production or exogenous addition. This increase in this acidic isoform of prohibitin is due to phosphorylation. It is possible that oestrogen induces phosphorylation of prohibitin and, thus, may be involved in the regulation of granulosa cell proliferation and the ontogeny of the ovarian follicle.

Androstenedione↗
PubMed1991

Major amputations done with palliative intent in the treatment of local bony complications associated with advanced cancer.

Palliative amputations were performed on 11 patients (7 men, 4 women) with disseminated disease to control local bony complications. The average patient age was 54 years (range 14-78 years). The primary diseases were melanoma/sarcoma (seven patients) and carcinoma (four patients). All had pain; eight had intractable pain that could not be controlled by analgesics. All 11 patients had additional severe local complications, which included recurrent pathological fracture (4), sepsis (2), hemorrhage (2), radiation necrosis (2), and iliofemoral thrombosis secondary to tumor (1). Previous attempts of palliation had been made in all 11 patients, and 8 had undergone previous operative procedures (5 had undergone two or more) prior to amputation. Three anterior hemipelvectomies, five posterior hemipelvectomies, two hip disarticulations, and one forequarter amputation were performed. All patients survived the surgery, and there were no intraoperative complications. All patients received dramatic relief of pain. Postoperative complications included two cases of flap necrosis and two infections; all resolved satisfactorily. The six patients who were nonambulatory before surgery ambulated postoperatively, and two eventually ambulated with a prosthesis. Six of 11 patients survived 1 year or longer, with a median postoperative survival period of 13 months (average 16 months). Although major amputations are viewed at times as offering little to already-compromised patients, they can improve dramatically the quality of life in selected patients.

Adolescent↗
PubMed1986

Containment theory and juvenile delinquency: a reevaluation through factor analysis.

All seven variables of containment theory were operationalized for questionnaires. Data were collected from 677 adolescents in a variety of high schools and correctional institutions, and divided into categories by race and sex. Factor analysis indicated that the structure of the relationships among the seven containment variables and delinquency was substantially different among black females.

Adolescent↗
PubMed1983

Comparison of counterimmunoelectrophoresis and latex particle agglutination in the detection of Streptococcus pneumoniae in blood cultures.

Blood cultures from 140 patients with chest infections were examined for the presence of pneumococcal antigen by both latex particle agglutination and counterimmunoelectrophoresis. Twenty-three samples (15 patients) were positive for pneumococcal antigen by counterimmunoelectrophoresis, of which 21 samples (13 patients) yielded Streptococcus pneumoniae in culture. Thirty-three samples (20 patients) were positive by latex particle agglutination, of which 24 samples (15 patients) were culture positive. The sensitivities and specificities were calculated and it was concluded that latex particle agglutination was the better test for the determination of the presence of pneumococcal capsular polysaccharide.

Antigens, Bacterial↗
PubMed1981

Childhood recurrent idiopathic paralysis of the lateral rectus.

Five case histories are discussed to emphasize the features of childhood recurrent idiopathic paralysis of the lateral rectus (CRIPLR). These features include (1) at least one recurrence of the paralysis, (2) a paralysis that may be so brief as to be overlooked or ignored; (3) lack of serious sequelae similar to lateral rectus dysfunction following viral illness; (4) left-sided involvement; and (5) the idiopathic nature of CRIPLR reflecting our inability to discover a cause.

Abducens Nerve↗
PubMed1979

The status of film/screen mammography. Results of the BENT study.

Results of the Breast Exposure: Nationwide Trends (BENT) study are presented. In this study, data were collected from 42 states and several other jurisdictions and the number of facilities found to have unusually high or low exposures during mammography was determined. Surveyors trained by representatives of the Bureau of Radiological Health then worked with these facilities to determine the source of the problem and recommend corrective measures. Contrast was found to be reduced by high "inherent" filtration, high kVp, or inappropriate imaging conditions, while resolution was impaired by excessive exposure time, as well as inappropriate imaging conditions. These and other problems are discussed and correlated with image quality.

Humans↗