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Biomedical subjects

W Roberts

Publications and source records attributed to W Roberts.

At least 73 records · Page 4Linked to original sources
PubMed1993

Expression of three forms of melanoma growth stimulating activity (MGSA)/gro in human retinal pigment epithelial cells.

PURPOSE: To characterize mRNA expression and protein production of the cytokine MGSA/gro in human retinal pigment epithelial (RPE) cells and to determine whether expression of MGSA/gro is modulated by serum and the cytokines interleukin 1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), or transforming growth factor beta (TGF beta) mediators implicated in proliferative vitreoretinopathy (PVR). METHODS: Reverse-transcription polymerase chain reaction was used to determine the steady-state mRNA expression of three forms of MGSA/gro, alpha, beta, and gamma, by cultured human RPE cells in the presence or absence of recombinant IL-1 beta, TNF alpha, or TGF beta, or when serum-starved cells were re-fed with medium containing serum. Immunocytochemistry was used to characterize RPE cell-associated MGSA/gro protein, and immunoprecipitation of MGSA/gro from cell-conditioned medium was used to demonstrate MGSA/gro secretion. RESULTS: MGSA/gro mRNA was expressed minimally under basal conditions. Expression for all three forms of MGSA/gro mRNA was induced in a dose- and time-dependent manner after exposure to IL-1 beta, to a lesser extent after exposure to TNF alpha, but not after exposure to TGF beta. Serum induced MGSA/gro alpha and gamma transcripts, but not beta transcripts. Cell-associated MGSA/gro was identified on RPE cells grown in the absence of cytokines, but MGSA/gro was not secreted under these conditions. Exposure to IL-1 beta did not consistently cause increased cell-associated MGSA/gro; however, IL-1 beta induced secretion of MGSA/gro in a time-dependent manner. CONCLUSION: MGSA/gro is produced by human RPE in response to mediators implicated in PVR. Because MGSA/gro is a pleiotropic modulator of cell proliferation and inflammation, it may contribute to the intraocular wound healing response that characterizes PVR.

Blood Proteins↗
PubMed1992

Modulation of macrophage colony stimulating factor in cultured human retinal pigment epithelial cells.

Steady-state mRNA expression and protein production of macrophage colony stimulating factor were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, macrophage colony stimulating factor mRNA expression was detected in unstimulated cells obtained from each of four separate donors. In these cells, mRNA expression was accompanied by secretion of macrophage colony stimulating factor protein into cell-conditioned medium; 48 hr after cells were switched to fresh medium, the mean (+/- S.D.) quantity of macrophage colony stimulating factor, measured by enzyme-linked immunoassay, was 5.1 +/- 2.3 ng 10(-6) cells. There was a dose- and time-dependent induction of macrophage colony stimulating factor mRNA after cells were exposed to recombinant human interleukin-1 and tumor necrosis factor alpha. Maximal mRNA induction was observed in cells exposed for 4 hr to interleukin-1 beta (5 U ml-1) or for 4-8 hr to tumor necrosis factor alpha; under these conditions, macrophage colony stimulating factor mRNA was induced up to 23- and 46-fold after exposure to interleukin-1 beta and tumor necrosis factor alpha, respectively. Similarly, macrophage colony stimulating factor protein production was enhanced after cells were exposed to recombinant cytokines. Protein secretion increased 1.3-2.5-fold (P less than 0.001) after exposure to interleukin-1 beta (5 U ml-1), and 1.2-1.6-fold after exposure to tumor necrosis factor alpha (P less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1992

Expression of interleukin-1 alpha, interleukin-1 beta, and an interleukin-1 receptor antagonist in human retinal pigment epithelial cells.

mRNA expression and protein production of interleukin-1 alpha, interleukin-1 beta and intracellular and secreted forms of an interleukin-1 receptor antagonist were measured in visually confluent monolayers of unstimulated cultured human retinal pigment epithelial cells and after cells were stimulated with recombinant cytokines. Using reverse transcription polymerase chain reaction, transcripts for interleukin-1 alpha and interleukin-1 beta were not detected in unstimulated cells from any of six donors whereas mRNA expression for both interleukin-1 alpha and interleukin-1 beta was readily induced in all six cell lines after cells were stimulated with recombinant IL-1 (alpha or beta), tumor necrosis factor alpha, or lipopolysaccharide. The combination of cycloheximide and recombinant interleukin-1 caused a 14-fold enhancement of interleukin-1 alpha and interleukin-1 beta mRNA expression above that observed after cells were stimulated with interleukin-1 alone. After stimulation by interleukin-1, cells produced intracellular interleukin-1 alpha protein, but did not secrete it into medium. In contrast, interleukin-1 beta protein was not detected in cell lysates or conditioned-medium after stimulation with interleukin-1. An intracellular interleukin-1 receptor antagonist was expressed constitutively by human retinal pigment epithelial cells; mRNA transcripts were enhanced in a dose and time dependent manner after cells were exposed to recombinant interleukin-1 or tumor necrosis factor alpha. In contrast, mRNA for a secreted form of the interleukin-1 receptor antagonist was not detected under basal conditions or after cells were stimulated by recombinant cytokines. Interleukin-1 receptor antagonist protein was found primarily in cell lysates; little interleukin-1 receptor antagonist protein was secreted by the cells. The presence of cell-associated interleukin-1 receptor antagonist was confirmed by immunocytochemistry. Levels of cell-associated IL-1 receptor antagonist protein were not significantly influenced by recombinant interleukin-1 or tumor necrosis factor alpha. Endogenous expression of interleukin-1 receptor antagonist may attenuate the effect of exogenous or endogenous interleukin-1, thus providing the RPE cell a means of maintaining interleukin-1 homeostasis in ocular inflammatory disease.

Cells, Cultured↗
PubMed1992

Adolescents' perceptions of significant individuals in their lives.

180 adolescents, aged 11-12 years, and 180, aged 15-16 years, from one Scottish secondary school participated in this study. The purposes of the investigation were: to determine the most significant family member and unrelated person in young peoples' lives; and to identify which characteristics rendered these persons important. 'Mother' and '(same sex) friend' emerged as the outstanding choices. Family members (except siblings) were associated with positive characteristics, whilst amongst unrelated adults, youth group leaders were viewed positively. By contrast, school teachers were primarily seen as occupying a challenging role. Where age and sex differences were found, it was invariably those in early adolescence and females who were more likely to attribute positive characteristics. These results are discussed in relation to the concept of 'mentoring' and the role of mentors in adolescents' lives.

Adolescent↗
PubMed1991

Attention deficit hyperactivity disorder: does cognitive behavioral therapy improve home behavior?

This study evaluates the effectiveness of cognitive behavioral therapy (CBT) in improving the home behavior of children with attention deficit hyperactivity disorder (ADHD). Twenty-five boys (age 7 to 13) with a diagnosis of ADHD were randomized to a CBT or supportive therapy control group. Outcome measures included parent and teacher ratings of the child on the Behavior Problem Checklist-Attention Problem Subscale (BPC-AP), and the Self-Control Rating Scale (SCRS), parent ratings on the Modified Werry Weiss Activity Scale, and child ratings on the Piers Harris Self-Concept Scale and Matching Familiar Figures Task. Data were analyzed using a two-way analysis of variance for main effects. A significant improvement favoring CBT was found on the Werry Weiss Scale, which measures the parent's perception of the child's hyperactivity in the home, and the child's rating of his/her self-esteem on the Piers Harris Self-Concept Scale. Other outcome measures did not demonstrate statistical differences. This research provides support for the use of CBT in children with ADHD. CBT was found to improve the parent's perception of the child's hyperactivity in the home as well as the child's self-esteem.

Adolescent↗
PubMed1990

A unique mental health network for Victorian aboriginal people.

The Victorian Aboriginal Mental Health Network (VAMHN) is a unique mental health programme for Aboriginal people in Australia. The network was set up in 1987. The services and programmes developed include a community consultation service, a psychiatric inpatient unit; and educational, evaluative and research programmes. Utilisation of the network has steadily increased and the demand for both primary and secondary consultations continues to grow.

Adult↗
PubMed1990

Application of automated image analysis to demonstrate the correlation between ras p21 expression and severity of gliomas.

We found a direct correlation between increasing ras p21 protein immunopositivity and severity of human glioma using computer-assisted, digital-image processing to quantify the amount of p21 immunoreactive to the monoclonal antibody RAP-5. We determined that there was a significant difference in reactivity between glioblastoma multiformes and more-differentiated astrocytomas (experiment-wise error less than 0.05). This result confirmed the conclusions made on the same tumors using standard light microscopy and visual examination. Immunohistochemistry quantized by automated image analysis may be a useful adjunct to current histopathological strategies since it decreases assay subjectivity and variation.

Antibodies, Monoclonal↗
PubMed1989

Co-morbidity: lessons learned about post-traumatic stress disorder (PTSD) from developing PTSD scales for the MMPI.

Results from efforts to develop and validate PTSD measures are promising, but a "gold standard" has not been achieved. Keane, Malloy, and Fairbank (1984) have developed an MMPI PTSD subscale that has been cross-validated with clinicians' classification of PTSD at acceptable levels of agreement, specificity, and sensitivity. There is, however, room for improvement. Empirical evidence is presented that indicates that the next round of efforts to increase reliability and validity of PTSD measures must account for the presence/absence of co-morbidity (i.e., the simultaneous occurrence of other psychiatric disorders). For example, differences are noted in MMPI group profiles and PTSD scales between psychiatric patients and substance abusers. Second, different MMPI items emerge as indicative of PTSD; these vary as a function of the presence of other Axis I disorders among groups of Vietnam combat veterans who seek treatment for substance abuse. Results substantiate that different MMPI items for classifying PTSD occur with groups that differ in co-morbidity. Improvements in PTSD scale development are more likely when the contributions of pre-existing or subsequently co-occurring psychiatric disorders are taken in account, as well as variations in level of personality maturity. The evidence suggests that a "family" of PTSD scales need to be developed that take into account co-morbidity differences.

Adaptation, Psychological↗
PubMed1989

Leuprolide acetate in the treatment of refractory or persistent epithelial ovarian cancer.

Leuprolide acetate (Lupron, TAP Pharmaceuticals, North Chicago), a gonadotropin-releasing hormone analogue, was administered subcutaneously at a 1-mg dose for a minimum of 8 weeks to 23 patients with refractory epithelial ovarian cancer. Eighteen of these patients were evaluable. There were no complete responses. Four patients (17%) had a partial response, with a median duration of 52 weeks. Three of six patients with grade 1 carcinomas had a partial response and two had stabilized disease. There was only one response among 15 patients with grade 2 or 3 disease. Therapy was well tolerated, with three patients complaining of hot flashes and two of mild pedal edema. Leuprolide acetate thus shows evidence of antitumor activity against refractory grade 1 epithelial adenocarcinoma of the ovary. Further trials with larger numbers of patients should be conducted.

Adult↗
PubMed1988

Neurologic complications of pelvic intraarterial chemoembolization performed with collagen material and cisplatin.

In three patients neurologic complications developed after chemoembolization procedures were performed with cisplatin and a new collagen material. Three patients with dominant unilateral stage III cervical carcinoma were entered into an investigative protocol attempting to control regional disease and pain with chemoembolization. All three patients had previously undergone surgery, radiation therapy, and intraarterial chemoembolization or chemoinfusion. Each case was complicated by neurologic deficits. A collagen material was administered that acts at a precapillary level and reduces the likelihood of collateral flow. The size of the material enables it to embolize the small feeding vessels of the spinal cord and peripheral nerves. The patients in this study also had predisposing factors to neurologic sequelae including the previous therapy and the contributing neurotoxicity of cisplatin. The neurologic complications in these patients are not easily explained by knowledge of the neurovascular anatomy. Even with meticulous technique, intraarterial chemoembolization of the pelvis with cisplatin and collagen can be complicated by serious neurologic deficits.

Adult↗