Search PubMed⌕ Search

Biomedical subjects

D M Barnes

Publications and source records attributed to D M Barnes.

At least 235 records · Page 13Linked to original sources
PubMed1986

Regional variation of cytosol androgen receptors throughout the diseased human prostate gland.

The heterogeneous histology of the normal and diseased human prostate is well established. This study has investigated variations in cytosol androgen receptor (AR) content throughout the diseased gland to establish the most suitable sites to obtain tissue for AR assay. Only then can AR be investigated as a potential predictor of response to endocrine treatment. In a transverse slice of an enucleated prostate showing benign prostatic hyperplasia (BPH) AR levels in 1-g segments varied from 109 to 1,212 fmol/g tissue (mean 483 +/- 273; median 406), with no negative areas. Areas of higher receptor concentrations corresponded to the glandular regions of sections obtained from a slice taken in juxtaposition; areas of low receptor concentrations corresponded to the stromal regions. A significant correlation (P less than .02) was observed between AR concentration and the proportion of glandular components of each segment. Specimens were also obtained from each of three sites from 38 prostates; 45% of all specimens contained AR; however, distribution of receptor throughout the prostate was uneven. AR were significantly more likely to be measured in the peripheral zone (71% positive) than in periurethral tissue (39% positive) whilst only 24% of specimens taken from the limit of the resection possessed AR binding capacity. Similar distribution patterns were observed in both benign and malignant prostates, although 16% more specimens from carcinomatous prostates contained receptor than did those from benign glands; this difference was maintained at each site. In addition receptor levels were consistently lower in benign than in malignant specimens. It is therefore desirable to know the histological composition of specimens used for AR measurement.

Cytosol↗
PubMed1986

Expression of epidermal growth factor receptor (EGF-R) in human lung tumours.

Epidermal growth factor receptor (EGF-R) expression was assessed in 63 lung tumour samples with a monoclonal antibody (EGF-R1) by indirect immunoperoxidase staining on cryostat sections. All 15 small cell lung cancer samples were negative whereas over 80% of the 48 non small lung cancer stained positively. In 30 bronchial biopsies two monoclonal antibodies against the cytoplasmic part of the EGF-R were evaluated. These antibodies showed weaker staining than EGF-R1. No additional or enhanced staining as compared with EGF-R1 was observed, suggesting a lack of enhanced expression of a truncated EGF-R analogous to the v-erb-B oncogene product. Monoclonal antibodies against the EGF-R may be helpful diagnostically in differentiating small cell from non small cell lung cancer and may also be important in elucidating biological differences in primary lung cancer.

Adenocarcinoma↗
PubMed1985

A mini-column method for routine measurement of human prostatic androgen receptors.

The complex heterogeneous nature of the human prostate gland is such that it is advisable to know the histological characteristics of each sample used for androgen receptor (AR) measurement. Adequate size of sample for AR determination is thus a problem if specimens provided during routine transurethral prostatectomy are to be used for both estimation of AR and histological examination. We present a simple method suitable for these small specimens in which [3H]R 1881 bound to AR is separated from free steroid on mini-columns of controlled-pore glass beads. Data obtained indicate a single class of binding sites of high affinity and low capacity with steroid specificity typical of an androgen receptor. The assay is suitable for samples as small as 20 mg wet weight and is linear using 25-125 microliter cytosol (correlation coefficient 0.995). Intra-assay variation is 6.8% and interassay variation 25.8% (n = 22) over 4 months. A single saturating concentration of steroid measures 97% of AR calculated by Scatchard analysis. Inclusion of high salt (0.4 M KNO3) and 10 mM dithiothreitol in incubation buffer at pH 8.4 are essential; inclusion of 10 mM sodium molybdate in the homogenisation buffer improves measurement. A comparison of AR measured in histologically similar samples obtained by a transurethral resectoscope (TUR) and a cold punch resectoscope (CPR) taken in juxtaposition demonstrated no difference in receptor content. Although carcinomatous samples contained significantly higher receptors levels than benign samples, no differences were observed between TUR and CPR specimens.

Chromatography, Gel↗