Search PubMed⌕ Search

Biomedical subjects

M Stone

Publications and source records attributed to M Stone.

At least 145 records · Page 8Linked to original sources
PubMed1984

Variance-covariance modeling with chromosome markers.

A binomial cell-marking process in the mitotic development of an organism is defined. Basic identities are established for the expectations, variances and covariances of the percentages of type-1 marked cells in general aggregates of cells. The identities are stated in terms of general probabilities that two cells, randomly picked from the aggregates, are in the same marked clone. The Nesbitt model for the X-chromosome inactivation marker and tissue differentiation is generalized in terms of these probabilities. The simultaneous use of two markers is analysed in similar terms. The application of the approach to a variety of aggregates of the haemopoietic system is briefly reviewed and discussed.

Animals↗
PubMed1984

Soft tissue anatomy of the tongue and floor of the mouth: an ultrasound demonstration.

Ultrasound technology has not been used extensively in the study of normal and abnormal oral physiology and speech. Features such as soft tissue detail, real-time motion display, and subject safety make ultrasound ideal for imaging the tongue and the floor of the mouth. This study demonstrates visualization of the muscles of the tongue and floor of the mouth for a normal subject using ultrasound imaging. By employing submandibular transducer placement of realtime sector scanners, tongue anatomy and motion were continuously visualized in sagittal or coronal planes. In addition to the entire tongue surface, much of the intrinsic anatomy was identified including: the genioglossus, geniohyoid, mylohyoid, and digastric muscles; fascial boundaries such as the median fibrous septum, floor intermuscular septum, and paramedian septums; and the hyoid bone. A tongue excised from a human cadaver was scanned using ultrasound and dissected to confirm the anatomy seen in the live tongue. Tongue surface shape and configuration of the intrinsic tissue structures were observed and compared for the phonemes /k/, /u/, and /i/. Anatomical landmarks in the resting and speaking tongue are discussed as well as applications in the fields of speech science and speech pathology.

Adult↗
PubMed1984

Characterization of tongue shape.

Mathematical techniques are described for analyzing tongue shapes obtained with ultrasound images. The surface of the mid-sagittal section of the tongue was approximated by discrete points. In turn, these points were used to approximate position, slope and curvature of the tongue surface at a fixed time during speech. Two approaches were employed. The first method involved the use of finite difference approximations to derivatives of the function of tongue position. The second utilized a curve fit. Both methods were examined for reliability. Results of these analyses on a simple, single speech sound are discussed.

Humans↗
PubMed1983

A general statistical model for clone--tissue studies, using X-chromosome inactivation data.

It is shown that certain simply defined probabilities, which involve the joint classification of two random cells by tissue and postinactivation clone, play a key role in the analysis of X-chromosome inactivation data and can be used to define tissue-specific and composite indices of 'incoherence', or lack of association, between clones and tissues. The experimental estimation of these probabilities is developed, with numerical illustration, for a general model of assay errors that embraces a spectrum of different assay techniques. Three estimation techniques are considered: the first, unconstrained by the requirements of any specific model for clone--tissue association; the second, constrained by a condition of dominated off-diagonal equality (DODE) that delineates a general class of models of the type used by Nesbitt (1971, Developmental Biology 26, 252-263); the third, additionally constrained by a condition of on- and off-diagonal equality (OODE) that holds for an 'equisampling' specialization of the Nesbitt model. The effects of natural relaxations of the assumptions implicit in the latter type of model are analysed within the framework constructed here.

Clone Cells↗
PubMed1982

Speech adaptation to dental prostheses: the former lisper.

Six of 13 former lispers studied reported unusual difficulty in speech adaptation to a dental prosthesis. Palatographic data showed that former lispers tended to make more frequent use of A-P shifts in tongue-palate placement as a compensatory strategy than did normal subjects. Tongue advancement was a common pattern. The nonadaptors showed the highest incidence of A-P tongue contact shifts as a compensatory strategy. Their use of this strategy was the most consistent, and they were more likely to retain the same articulatory speech patterns that were tried initially. Tongue groove width data for sibilants of nonadaptors in the familiar conditions showed a substantial incidence of further groove narrowing, a pattern normally seen only when a prosthesis is unfamiliar to the subject. In data on jaw position, nonadapting subjects had either not changed jaw position or adopted a closer jaw position by the end of 2 weeks. In both palatographic and jaw position data, it was possible to distinguish the adapting and nonadapting groups.

Adaptation, Physiological↗
PubMed1980

Localization of anti-mitochondrial antibody in experimental canine myocardial infarcts.

Alterations in cell and subcellular membrane integrity occur during evolving ischemic myocardial injury. We tested the hypothesis that an antibody against human liver mitochondria [anti-mitochondrial antibody developing in a patient with primary biliary cirrhosis] could identify altered cell membrane integrity in experimental canine myocardial infarcts. The proximal left anterior descending coronary arteries of 12 dogs were ligated and 1 hr later 131I-labeled F(ab')2 fragments from either a control human IgG (6 dogs) or anti-mitochondrial IgG (6 dogs) were injected. The 131I-labeled F(ab')2 anti-mitochondrial fragments concentrated maximally in the central infarct subendocardium [infarct-to-normal ratio of 9.2 +/- 3.5 (mean +/- SD) vs. 4.6 +/- 3.3 for control F(ab')2 IgG, P < 0.05]. There was also 1 1/2- to 2-fold greater anti-mitochondrial antibody F(ab')2 accumulation in the central infarct epicardium and the peripheral infarct subendocardium and subepicardium. Thus, an anti-mitochondrial antibody obtained from a patient with primary biliary cirrhosis concentrates in irreversibly damaged myocardium after experimental canine myocardial infarction. Presumably this occurs because of altered cell membrane integrity, which allows exposure of mitochondria to the anti-mitochondrial antibody. The F(ab')2 fragments of anti-mitochondrial antibodies labeled with suitable radionuclides should allow noninvasive scintigraphic detection of experimental acute myocardial infarcts.

Animals↗
PubMed1980

Estimation of pKB values for histamine H2-receptor antagonists using an in vitro acid secretion assay.

1 Histamine H2-receptor antagonism by burimamide, metiamide and cimetidine was analysed under apparent equilibrium conditions in the lumen-perfused isolated stomach preparation of the mouse. 2 The behaviour of these compounds was not incompatible with simple competitive antagonism but the estimated pKB values (-log KB) were all significantly lower, by about 1 log unit, than reference values reported for guinea-pig atrium or rat uterus. 3 There seems no need to propose that the parietal cell receptors are somehow different from the others; metiamide continually appears in the gastric juice so that a steady-state but not equilibrium can presumably be reached with respect to the bath concentration and this could keep the antagonist concentration artificially low in the region of the receptors.

Animals↗
PubMed1980

The Clark plot: a semi-historical case study.

A study has been made of the origins of the quantitative theory of simple competitive antagonism as manifest in the papers of Gaddum and of Clark. The classical data of Clark on the antagonism of acetylcholine by atropine were reanalysed by recently developed computer-based methods. It was seen how close Clark came to initiating a method having the following significant advantages over the Schild plot: (i) symmetrical treatment with respect to the control (zero antagonist) data; (ii) absence of difficulty with the cases where an estimated dose-ratio is less than unity; (iii) straightforward calculation of approximate standard errors for departure from overall simple competitivity at each antagonist level including control.

Acetylcholine↗
PubMed1980

Growth and development of the kidneys, heart and liver in S 5B/P1 and Osborne-Mendel rats fed high or low-fat diets.

Male Osborne-Mendel (OM) and S 5B/P1 rats were overfed from birth to 24 or 105 days. The effects of feeding a diet with 44 per cent or 3 per cent (w/w) fat, supplementary feeding during the suckling period, and reduced litter size, on body weight and on the weight and cellularity of the heart, liver and kidneys were evaluated. Three overfeeding techniques were used: (1) feeding a high fat diet, (2) reducing litter size, (3) force-feeding from 1-24 days. The overfeeding technique which exerted the greatest effect on growth was feeding a high-fat diet. In comparison to OM rats that suckled dams fed the low-fat diet, body weight as well as organ weight, DNA, protein and lipid were significantly elevated in 24-day-old OM rats that suckled dams fed the high-fat diet. In comparison to OM rats not overfed, the organs of the rats fed the high-fat diet contained significantly more cells at both 24 and 105 days, except for the heart which by 105 days contained more protein, but not DNA. Liver weight and growth in S 5B/P1 rats was similar, regardless of dietary manipulation. Compared to S 5B/P1 rats that suckled dams fed the low-fat-diet, kidneys were 12 per cent larger at 24 days and 19 per cent larger at 105 days in rats that suckled dams fed the high-fat diet and were thereafter fed a high-fat diet. Hearts of the latter rats were larger than the former rats at 24 days, but not at 105 days.

Animals↗
PubMed1979

An analysis of the influences of maternal age, gestational age, contraceptive method, and the mode of primary treatment of patients with hydatidiform moles on the incidence of subsequent chemotherapy.

In relation to the total number of births in the United Kingdom there was an excess of hydatidiform moles arising in women over 34 years of age and possibly also under 15. The incidence of trophoblastic tumour requiring chemotherapy after hydatidiform mole was greatest in the 30 to 34 years age group and it was also high in the 20 to 24 years age group. This distribution appears to be influenced by the morphology of the moles, the mode of their removal and the use of oestrogens and progestogens in the post-evacuation period. The need for chemotherapy for trophoblastic tumour after evacuation of a hydatidiform mole was found to be two- to three-fold greater in patients who had undergone a medical induction, hysterectomy or hysterotomy compared with those whose hydatidiform moles had been evacuated by vacuum or surgical curettage, or who had aborted spontaneously. The increased risk of chemotherapy was most marked in the earlier weeks of gestation.

Adolescent↗