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Biomedical subjects

M Stone

Publications and source records attributed to M Stone.

At least 181 records · Page 10Linked to original sources
PubMed1974

Promotion of growth of tumour cells in acutely inflamed tissues.

Acute inflammatory reactions were induced in rats by the intravenous injection of cellulose sulphate (CS) or an extract of normal rat lung homogenate (LH), or by intraperitoneal injections of Compound 48/80. These treatments greatly increased survival and clonogenic growth in the lungs of rats of intravenously injected allogeneic W-256 and Y-P388 tumour cells. Increase in the dose of intravenously injected CS caused a logarithmic increase in colony forming efficiency (CFE) of tumour cells in the lungs. CFE was not stimulated by the intravenous injection of rats with pharmacological mediators of inflammation (histamine, 5-hydroxytryptamine, bradykinin and prostaglandins PGE(1) and PGF(2α)) which are released from tissues by agents which induce inflammation. Stimulation of CFE by CS occurred in adrenalectomized rats but was inhibited by treatment of rats with an anti-inflammatory steroid, dexamethasone. CFE was stimulated by CS in tumour immunized rats; the inflammatory state did not prevent the expression of immunity but "rescued" a proportion (approximately 20%) of the injected tumour cells from immunodestruction in the lungs. A higher proportion of tumours grew in the paws of rats when a small number of W-256 cells were injected interdigitally into the acute inflammatory swellings produced by the local injection of paws with LH or CS.CS is a "synthetic heparin" which causes marked prolongation of blood clotting time and also increases fibrinolytic activity of the blood. Anticoagulant treatment of rats with heparin did not affect CFE. Thus, there was no direct correlation between blood clotting time and CFE of blood borne tumour cells in the rat.The mechanisms which may be responsible for the nonspecific growth promoting effects of inflammatory reactions induced by various types of tissue injury on tumour induction and growth are discussed.

Adrenalectomy↗
PubMed1971

Chromosome analysis before birth and its value in genetic counselling.

Chromosome analysis of amniotic cell cultures was achieved in 29 out of 30 consecutive patients who were referred for genetic counselling during pregnancy. Amniocentesis was performed without any apparent untoward maternal or fetal complication. The only pregnancy terminated was that of a carrier of X-linked granulomatous disease, in whom the amniotic cells showed that the fetus was male and also had Down's syndrome (trisomy G). Chromosome analysis in the remaining 28 patients showed normal karyotypes. The interval between amniocentesis and a definitive karyotype varied from 7 to 31 (average 18.4) days.The reliability of chromosome analysis from amniotic cell culture and of fetal sex determination by means of the sex chromatin and Y-fluorescence techniques was studied further in amniotic fluid from cases of therapeutic abortion and of rhesus incompatibility. The fetal sex was correctly determined in all cases. It is concluded that antenatal diagnosis of genetic disease by amniocentesis now permits a more practical approach to genetic counselling.

Abortion, Induced↗
PubMedDate not supplied

Real-time ultrasound visualization of tongue movement during swallowing.

Using noninvasive real-time ultrasound, tongue movement was visualized during single swallowing in eight normal subjects and one neurologically impaired patient with dysphagia and chronic aspiration. In normals, a clearly defined muscular wave of the tongue, traveling at approximately 15 cm/sec, carried a 5-cc test water bolus posteriorly. In the patient who had 12th cranial nerve weakness, there was complete absence of normal tongue activity and no midtongue bolus formation or transmission.

Adult↗
PubMedDate not supplied

Efficacy of multimodality therapy in gastric adenocarcinoma.

Multimodality therapy has not reproducibly improved the survival of patients with gastric adenocarcinoma. This is largely because the staging of disease has been imprecise and because the current regimens have only limited efficacy against advanced disease. Until staging is improved and active regimens are found, it will be difficult to identify synergism between surgery and other treatment modalities.

Adenocarcinoma↗
PubMedDate not supplied

Bone assessment in elderly women: what does a low bone ultrasound result tell us about bone mineral density?

Access to dual energy X-ray absorptiometry (DXA) can prove difficult for frail or elderly patients, and bone ultrasound may offer a practical alternative. Even after adjustment for bone mineral density (BMD), ultrasound readings are able to predict hip fracture in elderly women. We consider how bone ultrasound might contribute to bone assessment in a clinical setting. DXA remains the gold standard for bone assessment, with osteoporosis defined as a BMD result more than 2.5 S.D. below the young adult mean. Using an equivalent approach we defined an osteoporotic ultrasound result as broadband ultrasound attenuation (BUA)<54 dB/MHz. In 73 women aged 29-86 (mean 65) years DXA was used to measure BMD at lumbar spine and hip, and ultrasound to measure BUA at the heel. Correlation of BUA with BMD at femoral neck (r=0.64, P<0.001), and lumbar spine (r=0.55, P<0.001) was consistent with previously reported figures for this ultrasound system. All subjects with BUA below the 54 dB/MHz threshold value were shown to have low femoral neck BMD. Women (42%) aged over 65, but only 18% of younger women had low BUA results. In women over 65 years of age measurements of BUA achieved a sensitivity of 61% and specificity of 100% in prediction of low femoral neck BMD. Although a normal BUA did not exclude an osteoporotic BMD result at hip or lumbar spine, a low BUA appeared a highly specific predictor of low BMD at these sites. Since all those women identified as having a low BUA at the heel also had low BMD results, ultrasound appeared to identify a subgroup of elderly patients at a very high risk of fracture.

Journal Article↗
PubMedDate not supplied

Trauma in elderly people: what proportion of fractures are a consequence of bone fragility?

Epidemiologists have tended to equate osteoporotic fractures with those which occur after only moderate trauma, or which affect elderly people. We set out to critically examine this epidemiological approach, because even among elderly people some fractures will be a result of severe trauma and these cannot be assumed to reflect bone fragility. In a population based study of all Cardiff residents aged over 60 we identified everyone who presented with a fracture during 1996. We considered the events that led to each fracture, to establish which fractures were a result of 'severe' trauma: trauma greater than a fall from a standing height. We identified 1335 people who between them sustained a total of 1372 fractures. 168 (12%) of the fractures resulted from severe trauma, but in people aged over 80 only 6% of all fractures, 4% of hip fractures, and 3% of wrist fractures followed severe trauma. In older subjects severe trauma makes only a very small contribution to the causation of fracture, so that the age-sex distribution of fractures following moderate trauma closely resembles that of fractures overall. For epidemiological purposes it does appear justifiable to equate the consequences of bone fragility with the occurrence of osteoporosis associated fractures in elderly people.

Journal Article↗
PubMedDate not supplied

Biological thermal detection: micromechanical and microthermal properties of biological infrared receptors.

Bioinspired design of biomimetic sensors relies upon the complete understanding of properties and functioning of biological analogues in conjunction with an understanding of their microstructural organization at various length scales. In the spirit of this approach, the microscopic properties of infrared (IR) receptors of snakes with "infrared vision" were studied with scanning thermal microscopy and micromechanical analysis. Low surface thermal conductivity of 0.11 W/(m K) was measured for the IR receptor surfaces as compared to the nonspecific skin areas. This difference in surface thermal conductivity should result in a significant local temperature gradient around the receptor areas. Micromechanical analysis showed that pit organs were more compliant than surrounding skin areas with an elastic modulus close to 40 MPa. In addition, the maximum elastic modulus was detected for the outermost layer with gradually reduced elastic resistance for the interior. The porous microstructure of the underlying tissue combined with the highly branched microfibrillar network (Biomacromolecules 2001, 2, 757) is thought to be responsible for such a combination of biomaterial properties. Considering these biomaterials features, we postulated a possible design of an artificial photothermal detector inspired by the microstructure of natural receptors. This bioinspired design would include a microfabricated cavity filled with an ordered lattice of microspheres with a gradient periodicity from the surface to the interior. Such a "photonic cavity" could provide an opportunity for multiple scattering at wavelength tuned to 8-12 microm as a range of highest sensitivity.

Animals↗
PubMedDate not supplied

Translocation of c-ab1 oncogene correlates with the presence of a Philadelphia chromosome in chronic myelocytic leukaemia.

The localization of cellular oncogenes near the break points of tumour-specific chromosomal aberrations suggests an involvement of these genes in the generation of neoplasms. Recently, we demonstrated the translocation of the human cellular homologue (c-ab1) of the transforming sequence of Abelson murine leukaemia virus (A-MuLV) from chromosome 9 to the Philadelphia chromosome (Ph1) in chronic myelocytic leukaemia (CML). In an attempt to investigate the significance of this translocation in the pathogenesis of CML, we have now studied two CML patients with complex translocations, t(9; 11; 22) and t(1; 9; 22), and two CML Ph1-negative patients with apparently normal karyotypes. In addition to using blot hybridization with human c-ab1 probes and DNA from rodent: CML cell hybrids as before, we have used in situ hybridization of these probes directly to metaphase chromosomes of CML patients. These studies show that the c-ab1 gene is translocated in Ph1-positive but not in Ph1-negative CML patients. CML without the Ph1 chromosome seems to be a distinct entity with a different origin, and this view is supported by clinical observations including correlations which reveal a poorer prognosis.

Abelson murine leukemia virus↗