Search PubMed⌕ Search

Biomedical subjects

M E Harper

Publications and source records attributed to M E Harper.

At least 73 records · Page 4Linked to original sources
PubMed1992

Studies on the proliferation, secretory activities, and epidermal growth factor receptor expression in benign prostatic hyperplasia explant cultures.

Short term explant cultures of benign prostatic hyperplasia (BPH) tissues were studied immunohistochemically to characterise both the morphological changes within the explant tissue and the cellular origin of the epithelial cell outgrowth. Altered patterns of expression of cytokeratins, prostate specific antigen (PSA) prostatic acid phosphatase (PAP), and epidermal growth factor (EGF) receptor were observed. After sloughing of the secretory epithelium in the majority of the acini repopulation and outgrowth of a monolayer was accomplished by cells which were strongly positive for stratifying keratin and EGF receptor and negative for PAP and PSA, indicative of a basal cell phenotype. The peak of proliferation in the acini, as assessed by Ki-67 immunohistochemistry, occurred after 2-4 days in culture. Preliminary studies on BPH tissue xenografts in nude mice indicated that better preservation of normal morphology, secretory activity, and antigen expression could be achieved.

Acid Phosphatase↗
PubMed1992

Relationship of proliferating cell nuclear antigen (PCNA) in prostatic carcinomas to various clinical parameters.

Proliferating cell nuclear antigen (PCNA) expression was determined immunohistochemically, using a monoclonal antibody PC10, in 102 prostatic carcinoma samples and in prostate tissue from 21 patients with benign prostatic hyperplasis (BPH). The percentage of cells with stained nuclei ranged from 1% to 58% in the carcinoma specimens and 0% to 10% in the BPH specimens. A semiquantitative scoring system was devised for the degree of PCNA positivity observed in the tumors. Statistical analysis of the PCNA score in relation to the histological grade of the tumors gave a significant positive or negative correlation between these parameters P less than 0.001. No significant correlation between PCNA score was, however, seen with metastatic status, T category (TMN classification) of the primary tumor, or the patient's age at diagnosis. In 65 prostatic cancer patients of known survival, those individuals whose tumors had a PCNA score of +/- (less than 10% of nuclei stained) were compared with those patients whose tumors were either 1+, 2+, or 3+ (greater than 10% of nuclei stained). Life table analysis of the two groups indicated that the patients with the lower PCNA score survived significantly longer than those with the higher PCNA scores, P less than 0.04. Comparison of the Ki-67 expression in frozen sections with the PCNA expression in wax-embedded tissue of 86 prostatic carcinomas was also undertaken. A significant correlation between these two parameters was found, P less than 0.001, although the growth fraction estimated by Ki-67 expression was generally lower than that given by the PCNA scoring system.

Antibodies, Monoclonal↗
PubMed1992

Pathological and clinical associations of Ki-67 defined growth fractions in human prostatic carcinoma.

Estimation of the growth fraction of 153 prostatic carcinoma specimens employing Ki-67 immunostaining was undertaken and its relationship to various clinical parameters investigated. In prostate specimens, the percentage of tumour nuclei expressing Ki-67 antigen was measured and assigned a Ki-67 score. It was observed that high Ki-67 scores were associated with the poorly differentiated tumours, the correlation of this proliferation marker with histological grade was found to be significant (P less than 0.001). No relationship was observed between the Ki-67 score of the primary tumour with either the patient's age or with the primary tumor stage (T category). The metastatic status of the patient at diagnosis and the Ki-67 score of the tumour were correlated (P less than 0.05), higher Ki-67 scores being associated with M1 disease. Life-table analysis of 86 patients who subsequently received androgen withdrawal therapy, was undertaken with reference to the various Ki-67 scores of their primary tumors. A statistically significant difference in survival times was observed in patients whose Ki-67 values were less than 1% (P less than 0.0001) when compared to those patients whose tumours expressed 1% and over Ki-67 positivity, the former having longer survival times. When patients were subdivided according to their metastatic status and similar life-table analyses were carried out, no statistical difference was found between survival times and Ki-67 scores in M0 staged patients. In the M1 population of patients, however, those patients whose tumours were negative for Ki-67 expression had significantly longer survival times than those patients whose tumours exhibited positive Ki-67 staining (P less than 0.01). Comparing M1 staged patients whose prostate tumor cells exhibited less than 1% Ki-67 positive nuclei with M1 staged patients whose prostate tumour cells contained 1% and higher Ki-67 stained nuclei, a significantly longer survival time was found in the former group of patients (P approximately 0.0001).

Adult↗
PubMed1991

Steroid hormones and the pathogenesis of benign prostatic hyperplasia.

The pathogenesis of benign prostatic hyperplasia (BPH) is still poorly understood: there is, however, general acceptance that the condition is not premalignant and that it has an etiology distinct from that of cancer. Interest now focuses on the biochemistry of the target prostate cells and the propensity of the gland for uncontrolled growth. Dihydrotestosterone (DHT) is the active intracellular androgen formed from testosterone by 5 alpha-reductase. DHT concentrations appear a little higher in BPH tissue than in normal tissue, and there is no doubt that DHT-receptor complex modulates gene expression. Current studies suggest that DHT is essential but not sufficient for proliferation, and that other regulatory factors, including peptide growth factors, are prerequisite. The growth responsiveness of prostate tissue to androgens may be dependent on the balance between epithelial and stromal tissues, with biologic processes in the epithelium indirectly controlled by androgen-dependent mediators of stromal origin.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1990

Erythrocyte membrane lipid alterations in undernourished cerebral palsied children during high intakes of a soy oil-based enteral formula.

Five undernourished children with severe cerebral palsy (CP) were tube-fed sufficient volumes of Isocal to allow rapid weight gain. Isocal provided, on average, 88% of their daily energy intake for at least 25 days. The purpose of our study was to correct the undernutrition and to analyze the major erythrocyte phospholipids before and after feeding periods for possible feeding and disease-related differences. The fatty acid profiles of erythrocyte membranes from CP children were compared with those from 12 healthy children and with the fatty acid composition of the formula. There were no clinical or biochemical indications of essential fatty acid deficiency. The feeding of a soy oil-based formula increased the proportions of 18:2n-6 in the phospholipids. The increases occurred predominantly in phosphatidylcholine followed by phosphatidylethanolamine. Despite such large dietary intakes of soy oil, no changes were observed in the phospholipid concentrations of 20:4n-6, 18:3n-3, 20:5n-3, or in the C22n-6 and C22n-3 fatty acids. These findings are consistent with an inhibition of the delta 6 desaturase by high dietary linoleate.

Adolescent↗
PubMed1990

The effect of an anti-membrane antibody-methotrexate conjugate on the human prostatic tumour line PC3.

Methotrexate (MTX) was linked, via an active ester intermediate, to a purified IgG fraction of rabbit polyclonal antiserum raised against a cell membrane preparation from the human prostatic cell line PC3. The resulting conjugates contained an average of 0.044 mg of MTX per mg of antibody with acceptable losses in both the binding activity of the immunoglobulin (27.5%) and the enzyme inhibitory activity of the drug (32% at a MTX concentration of 3 x 10(-7) M). Using cultures of PC3 cells the antibody-MTX (Ab-MTX) conjugates were observed to be as effective as free drug in causing cell death and more effective than non-immune IgG-MTX (NIgG-MTX) conjugates. When athymic nude mice bearing PC3 tumours were administered with Ab-MTX conjugates, significant reductions in tumour growth rates were observed compared to animals given saline, MTX alone or NIgG-MTX conjugates (P less than 0.01 in all cases). Furthermore, the accumulation of radioactive MTX in the tumour tissue of animals injected with these Ab-MTX conjugates was 16-fold greater than those given free drug and 8.6-fold greater than those administered with NIgG-MTX conjugates. Uptake by the reticuloendothelial system, however, was not significantly different when animals from each treatment group were compared.

Animals↗
PubMed1990

The absence of adapted sodium and potassium transport in erythrocytes of cerebral palsied children with secondary malnutrition.

Previous studies of erythrocyte ion (potassium and sodium) transport during marasmus and kwashiorkor have indicated increased passive permeation to both ions in both syndromes, and increased Na,K pump activity in kwashiorkor and reduced activity in marasmus. Children with severe cerebral palsy (CP) frequently suffer secondary protein energy malnutrition (PEM). Unlike marasmus and kwashiorkor, this PEM is uncomplicated by micronutrient deficiency, parasitism and infections. Because of deformities classification of PEM cannot be performed in these children by stature-based anthropometry, therefore we used triceps skinfold thicknesses less than the fifth percentile and absence of weight gain in the previous year as criteria for malnutrition. K influx data from well- and malnourished CP children, and from well-nourished controls reveal that ouabain-sensitive K influx is highest in malnourished CP, followed by well-nourished CP (P = 0.02), and lowest in controls (P less than 0.001, vs. malnourished). Determinations of ouabain-sensitive Na efflux, though less precise and therefore more variable, were consistent with this finding of no decrease of Na,K pump activity occurring during the development of this malnutrition. There were no statistically significant differences in ouabain-insensitive fluxes of either Na or K. Ion transport in undernourished CP children thus resembles that found in kwashiorkor rather than in marasmus; but oedema is rarely seen in this form of secondary PEM.

Adolescent↗
PubMed1987

Steroid hormone concentrations in relation to patient prognosis and prostate tumour grade.

Survival of patients who received endocrine therapy as first-line treatment for their prostatic cancer was statistically analysed in relation to several parameters, primary tumour stage, metastatic status, age, pretreatment plasma hormone concentrations and Gleason grade. Prognostic indices were derived for both M0 and M1 patients in which Gleason grade and plasma testosterone concentrations were significant prognostic factors. In the M1 patients growth hormone values were also significant and to a lesser degree age. The relationship of Gleason grade to testosterone, growth hormone, prolactin, the gonadotrophins and age was also analysed. No significant differences in any of these hormones was noted with increasing Gleason grade but the age of patients with Grade 5 tumours was significantly lower.

Carcinoma↗
PubMed1986

Detection of HTLV-III RNA in lungs of patients with AIDS and pulmonary involvement.

A majority of pediatric patients and rare adult patients with the acquired immunodeficiency syndrome (AIDS) develop a chronic respiratory disorder referred to as "lymphocytic interstitial pneumonitis" (LIP). Efforts to identify an infectious agent responsible for this process so far have failed. In this study, frozen sections of lungs from patients with AIDS and pulmonary disease were tested by in situ molecular hybridization for the presence of cells infected with human T-cell lymphotropic virus type III (HTLV-III) and expressing viral RNA. In the case of an infant with LIP, a relatively high frequency (0.1%) of cells in the lung were found to be positive for HTLV-III RNA. This number is the lower limit of total cells infected since the in situ hybridization technique as applied in this study depends on expression of HTLV-III genes, and previous evidence indicates that a proportion of cells infected with HTLV-III may not express viral RNA. Moreover, this degree of infection of the lung is likely limited to LIP, since in ten patients with AIDS and pulmonary diseases other than LIP, only 0% to 0.002% of cells in lung were positive for viral RNA expression. Thus, HTLV-III may play a direct causal role in the development of LIP in infected patients, implicating its involvement in yet another of the diverse clinical diseases associated with this virus.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Infectious mutants of HTLV-III with changes in the 3' region and markedly reduced cytopathic effects.

A variant of human T-lymphotropic virus type III (HTLV-III) is described that replicates but does not kill normal human T cells in vitro. This variant, designated X10-1, was derived from the genome of a cytopathic HTLV-III clone (pHXB2D) by excision of a 200-base pair segment in the 3' region of the virus, spanning the env and 3'-orf genes. Comparable variants with 55 to 109 base pairs deleted exclusively in 3'-orf produced, in contrast, virus that was extremely cytopathic. On the basis of these findings it is concluded that the 3'-orf gene is not required for cytopathogenicity or replication of HTLV-III. In addition, the results suggest that virus replication and cytotoxicity are not intrinsically coupled. Furthermore, since clone X10-1 retains the ability to trans-activate genes linked to the viral long terminal repeats, trans-activation per se is not responsible for T-cell killing by HTLV-III. These results also raise the possibility that the carboxyl terminus of the envelope gene of HTLV-III has a direct role in T-cell killing by this virus.

Acquired Immunodeficiency Syndrome↗
PubMed1986

In situ hybridization--application to gene localization and RNA detection.

In situ hybridization offers a direct approach for localization and quantitation of nucleic acid sequences in cellular preparations. Recent improvements in technology and methodology make possible the detection of DNA and RNA of relatively low copy number. For example, development of in situ hybridization methods for detection of single copy DNA sequences on mitotic chromosomes has led to general use of this technique for gene mapping of the human genome. More recently, improvements in methodology for detection of low abundancy RNA make possible a facilitated analysis of gene expression, both from cellular genes and exogenous sequences, such as viral genomes. In situ hybridization is now a powerful method for studying nucleic acid organization and function in normal cells, as well as in malignant cells, which should contribute to better understanding of the cell transformation process.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Detection of lymphocytes expressing human T-lymphotropic virus type III in lymph nodes and peripheral blood from infected individuals by in situ hybridization.

By using in situ hybridization methodology, we have directly examined primary lymph node and peripheral blood from patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex for the presence of human T-lymphotropic virus type III (HTLV-III) viral RNA. Mononuclear cell preparations were hybridized with a 35S-labeled HTLV-III-specific RNA probe and exposed to autoradiographic emulsion for 2 days. HTLV-III-infected cells expressing viral RNA were detected in approximately 86% (6/7) of lymph node and 50% (7/14) of peripheral blood samples studied. However, in all patient samples examined, labeled cells were observed at very low frequency (less than 0.01% of total mononuclear cells). The HTLV-III-infected cells exhibited morphological characteristics consistent with that of lymphocytes and expressed viral RNA at relatively low abundance (20-300 copies per cell). These results demonstrate that HTLV-III expression in lymph node and peripheral blood is very low in vivo. Furthermore, the lymph node hyperplasia observed in HTLV-III-associated lymphadenopathy is not directly due to proliferation of HTLV-III-infected lymphocytes.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Immunocytochemical assay for estrogen receptors applied to human prostatic tumors.

An immunocytochemical assay using a monoclonal antibody to estrogen receptor was applied to frozen sections of 43 prostatic tumors. In addition, in 16 tumors the results of the immunocytochemical assay were compared with those obtained using an enzyme immunoassay for estrogen receptor, a tritiated ligand binding assay, and a histochemical procedure using fluorescein-labeled estradiol conjugates. Specimens from 14 patients with benign prostatic hyperplasia and 29 patients with prostatic carcinoma were analyzed in assays in which human breast carcinoma specimens of high, medium, low, or negative estrogen receptor content acted as controls. The intensity of nuclear staining and the percentage of stained cells in the breast sample controls correlated well with estrogen receptor content as determined by both the enzyme immunoassay and the tritiated ligand binding assay. None of the fixed, frozen sections from the 43 prostatic tumors exhibited nuclear staining of either the benign or the malignant epithelial cells or of the stromal components. Negative results were also obtained with the tritiated ligand binding assay. The majority of prostatic samples were negative when using the enzyme immunoassay but four specimens had a mean value of 6.2 fmol/mg protein which is just above the sensitivity of the assay. Using fluorescein-labeled estradiol conjugates both cytoplasmic and nuclear binding was observed in the prostatic samples which did not correlate with the results obtained by the other three procedures.

Histocytochemistry↗