PubMed Health⌕ Search

Biomedical subjects

M F Thomas

Publications and source records attributed to M F Thomas.

8 recordsLinked to original sources
PubMed2001

Occlusal caries diagnosis in molar teeth from bitewing and panoramic radiographs.

INTRODUCTION: Previous studies have implied that the panoramic radiograph was inferior to the bitewing radiograph for caries diagnosis. However, these clinical studies lacked a method of validation. The aim of this study was to use an electronic caries meter (ECM II, LODE, Groningen, The Netherlands) to validate occlusal caries diagnosis made from bitewing and panoramic radiographs. MATERIALS AND METHOD: Forty-nine Army recruits were examined with the ECM, and had bitewing and panoramic radiographs taken. In total 299 molar occlusal surfaces were available for examination. Seven examiners viewed the bitewing and panoramic radiographs on two separate occasions and assessed each occlusal surface for dentine caries as 1: almost definitely no caries, 2: probably no caries, 3: unsure, 4: caries probably present, and 5: caries almost definitely present. This was repeated on 20% of the radiographs at two further separate sittings. ECM conductance readings greater than 9 were taken to indicate dentine caries. Examiner decisions that caries was probably and definitely considered to be present were taken as positive diagnoses. RESULTS: Bitewing and panoramic radiographs provided sensitivity values of 0.25 and 0.19 and specificity values of 0.93 and 0.97 respectively. ROC analysis indicated no statistically significant difference in diagnostic quality between the bitewing and panoramic radiographs. Intra-examiner reproducibility was found to be poor to moderate (Kappa values for bitewing = 0.31-0.44, panoramic = 0.07-0.54). CONCLUSION: No difference in overall diagnostic performance was found between bitewing and panoramic radiographs for the diagnosis of occlusal dentine caries.

Analysis of Variance↗
PubMed1999

Insulin-like growth factor-I protects myoblasts from apoptosis but requires other factors to stimulate proliferation.

Insulin-like growth factor-I (IGF-I) has been shown to stimulate myoblast proliferation for a limited time after which serum is required to reactivate IGF-I-stimulated myoblast proliferation. The aim of these studies was to determine whether IGF-I can stimulate myoblast proliferation and/or inhibit apoptosis alone or whether co-factors are necessary. This was achieved by investigating the proliferative response of L6 myoblasts to IGF-I and horse serum (HS) and by examining the status of cells in terms of cell number, substrate adherence, cell viability and DNA laddering following incubation with IGF-I and HS. L6 myoblasts proliferate in response to IGF-I after 36 h is not due to accumulation of waste products or lack of IGF-I. The addition of a low level (1% v/v) of HS restores the ability of myoblasts to proliferate in response to IGF-I and this supports the existence of a mitogenic competence factor. Furthermore, myoblasts failing to proliferate in response to IGF-I after 36 h regain the capacity to respond to IGF-I for a further period of 36 h when exposed to fetal bovine serum. Following the initial (36 h) phase of IGF-I-stimulated proliferation, removal of both IGF-I and HS led to a dramatic (60%) reduction in the number of cells fully attached to the culture vessel, with 60% of the completely detached cells dead. Agarose gel electrophoresis of extracts from these detached cells revealed higher levels of DNA laddering than extracts prepared from attached cells with IGF-I present. This suggests that IGF-I acts as a survival factor by protecting cells from apoptosis. In conclusion these experiments support the presence of a mitogenic competence factor in horse serum, which restores the ability of cells to proliferate in response to IGF-I. Unlike proliferation, protection against apoptosis is achieved by IGF-I or HS independently of each other.

Animals↗
PubMed1998

Nagorno Karabakh.

Explore the source record for details and available documents.

Azerbaijan↗
PubMed1993

[Membrane fatty acids and blood antioxidants in 77 patients with HIV infection].

We have measured the fatty acid (FA) composition of erythrocyte membranes and plasma anti-oxidants in HIV+ patients. Saturated FA are higher and poly-unsaturated FA lower than in controls (P = 0.02). Selenium (Se) is lower in patients less than 400 CD4 cells/mm3 (P = 0.002). Vitamin A is lower in the HIV+ regardless of the CD4 cell count. Se and vitamin A are correlated to nutritional markers (body mass index and albumin).

Antioxidants↗
PubMed1977

Hematologic responses to carbon monoxide and altitude: a comparative study.

Groups of 40- and 90-day-old rats were exposed to 500 ppm CO (HbCO=31-43%) and simulated altitude (15,000 ft). Resulting hematologic changes were monitored after 1 day, 1 wk, 3-4 wk, and 9-11 wk of exposure. The two treatments resulted in similar changes in hemoglobin (Hb) and hematocrit ratio (Hct) in the young rats, while in the older group there were several small, but significant differences in these parameters. Mean corpuscular hemoglobin concentration (MCHC) fell 12.4-15.1% during the 1st wk of exposure in all groups except the young altitude rats, which remained at the control value. The former groups returned to control levels by the 3rd to 4th wk of exposure. Red cell 2,3-diphosphoglycerate (2,3-DPG) increased 21.6-26.1% above control during 3-4 wk of altitude exposure, but later (9-11 wk) returned toward control levels. CO exposure resulted in a sharp decrease in 2,3-DPG after 1 day of exposure only in the young rats. 2,3-DPG level progressively decreased with age in control rats. The effects of CO and altitude although similar in several respects (i.e., Hb, Hct, MCHC) differ with regard to red cell 2,3-DPG.

Adaptation, Physiological↗
PubMedDate not supplied

The role of Sb(5+) in the structure of Sb(2)O(3)-B(2)O(3) binary glasses--an NMR and Mössbauer spectroscopy study.

Glasses of general formula xSb(2)O(3) (1-x)B(2)O(3) (0 </= x </= 0.8) have been prepared by conventional melt- quenching. Mössbauer spectroscopy shows that a fraction of the Sb(3+) is converted to Sb(5+) and this fraction increases with x. High-field (11)B MAS NMR gives well-resolved resonances from boron atoms which are 3- and 4-coordinated to oxygen. The fraction of 4-coordinated boron, N(4), goes through a maximum value of 0.12+/-0.01 at x = 0.5. The position of the maximum in N(4) is consistent with the cation potential for Sb(3+), as observed for other systems. However, the low value of N(4) at this maximum is not so readily explained. The values are similar to those predicted if [BO(4)](-) were stabilised by [SbO(4)](+) but the trends with composition are different.

Journal Article↗