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Biomedical subjects

K Griffiths

Publications and source records attributed to K Griffiths.

At least 217 records · Page 12Linked to original sources
PubMed1978

Relationship between oestrogen-receptor content and histological grade in human primary breast tumours.

A series of 300 patients presenting consecutively with primary operable breast cancer has been studied. A significant correlation was found between oestrogen-receptor (ER) content and histological grade: the better-differentiated tumours rarely lacked receptor. This correlation was significant only in women defined as post-menopausal. Data on early recurrence of disease indicate a worse prognosis for women in whom primary tumours are ER-.

Adult↗
PubMed1978

Oxygen incineration and electron microscope x-ray microanalysis of mineral particles in biological tissues.

Techniques employed for the recovery from biological tissues of noncombustible fine particles such as asbestos, talc, kaolin and diatomaceous material were assessed by electron microscope x-ray microanalysis. Recovery procedures which have been proven successful for lung tissue were found to be impracticable for more solid types of tissues. Digestion techniques employing acids, alkalis or enzymes and standard incineration procedures were found to be unsatisfactory for human adrenal, cervix, liver and ovarian tissues when the resultant residues were examined by electron microscope microanalysis. The recovered particles were often completely masked with residues which were shown to be composed of organic elements. The use of oxygen during the incineration process completely removed this contaminating material in nearly all cases studied. When such procedures were used, clearly defined particles were recovered from the tissue, thereby permitting x-ray analysis. A quantitative analysis could then be made to estimate the particle content in a variety of tissues.

Electron Probe Microanalysis↗
PubMed1978

Internal quality control of radioimmunoassays.

A modified cumulative sum technique has been applied to radioimmunoassay quality control data. The method is approximately 50% more efficient in detecting systematic changes in the mean and variance of quality control values for plasma samples than more widely used conventional methods. The salient features of the technique have been restricted to changes in the mean quality control value of a plasma pool, but potential applications to changes in variance and as a diagnostic aid to problems in radioimmunoassay have been evaluated. The method is independent of computing facilities and statistical expertise since all computations have been presented in the form of a nomogram and thus can be used by technicians at the bench.

Estradiol↗
PubMed1978

Estrogen receptor assay in primary breast cancer and early recurrence of the disease.

Estrogen receptor assays of primary breast tumors have been related to early recurrence of the disease. A significantly longer disease-free interval was found in women whose primary tumor was estrogen receptor positive. Although there was no relationship of receptor content to stage of disease at mastectomy, the greatest difference between recurrence rates was found when the tumor had spread to the lymph nodes, especially to those in the apex of the axilla or in the internal mammary chain. Presence of estrogen receptor is closely related to histologically well-differentiated tumors, but it was found that poorly differentiated estrogen receptor-negative tumors recurred earlier than poorly differentiated receptor-positive tumors and had a very unfavorable prognosis.

Breast Neoplasms↗
PubMed1978

The perception of solid form in early infancy.

Day and McKenzie determined the rate of habituation of fixation of young infants to repeated visual presentations of a cube. They found the habituation rate to be the same when the stimulus orientation changed between presentations as when it was fixed, and they interpreted this as evidence of shape constancy. However, a failure to discriminate between cubes in different orientations is only evidence of shape constancy if the infant can at the same time discriminate the cube from other cubelike forms. The experiment described here contrasted the rate of habituation of fixation of 12-week-old infants to a homogenous stimulus series (a cube presented in different orientations) with the rates of habituation to various heterogeneous series, in each of which a cube was alternated with some other solid. It was found that, while the infant could distinguish a cube from a photograph of a cube and a concave solid (an L-form), there was no evidence of discrimination between the cube and either a wedge or a truncated pyramid. The results imply limits to the young infants capacity to resolve solid form.

Discrimination Learning↗
PubMed1977

Initiation and elongation of polyribonucleotide chains on rat ventral-prostate chromatin transcribed by homologous ribonucleic acid polymerase B.

The characteristics of initiation of RNA synthesis and the elongation of RNA chains on rat ventral-prostate chromatin by RNA polymerase B were investigated by two methods. 1. Initiation was carried out under low-salt conditions with three ribonucleoside triphosphates, and elongation was begun in the absence of reinitiation by the addition of the fourth ribonucleoside triphosphate and increasing the salt concentration. 2. Stable initiation complexes were formed by preincubation of enzyme with template at 37 degrees C, elongation was started by the addition of all four ribonucleoside triphosphates and reinitiation or spurious RNA synthesis was prevented by rifamycin AF/013. The latter method gave more reliable results. The dependence of those parameters on the androgenic status of the animal was studied. During the first 24h after castration, elongation was mainly affected, whereas after 72h a smaller number of initiation sites for RNA polymerase B on chromatin was evident. Considerable diurnal variations in the various parameters were observed. Changes in the relative concentrations of the chromatin-associated proteins were also observed after castration. In the rat ventral-prostate gland androgenic steroids may not only influence one stage of the transcriptional process, but may affect many factors involved in the control of gene expression.

Amanitins↗
PubMed1977

The detection and measurement of D-norgestrel in human milk using Sephadex LH 20 chromatography and radioimmunoassay.

An accurate sensitive method for the assay of D-norgestrel in human milk is described. The steroid is isolated from an ether extract of milk by Sephadex LH 20 chromatography in the system iso-octane-benzene-methanol (70:20:10 v/v). The radioimmunoassay utilises a specific antibody produced in rabbits against D-'norgestrel 3-(O-carboxymethyl) - oxime coupled to bovine serum albumin with D-norgestrel 3-(0-carboxymethyl) -oxime/ [125I]-iodohistamine conjugate as radioligand. Accuracy, sensitivity and blank value are satisfactory. Milk samples were obtained from three subjects treated with 30 microgram/day D-norgestrel, treatment commencing two weeks following parturition. Significant amounts of D-norgestrel were found, ranging between 92-135 pg/ml milk at the end of the first two-week treatment regimen. In two of three subjects, lower, but significant concentrations (53 pg and 35 pg/ml respectively) of steroid were found at the end of four weeks treatment. In the third subject, D-norgestrel could not be detected at this time. As a check on the specificity of the assay, three samples were submitted to additional chromatographic purification on alumina thin layer in the system benzene-cyclohexane-ethanol (70:27:3 v/v). Although this additional chromatographic step yielded somewhat lower values, agreement between the respective sets of results was good. The significance and implications of these findings are discussed.

Chromatography, Gel↗