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Biomedical subjects

M Trotter

Publications and source records attributed to M Trotter.

10 recordsLinked to original sources
PubMed1991

The effect of hydralazine on blood flow and misonidazole toxicity in human tumour xenografts.

The effect of post-irradiation hypoxia induced by 5 or 30 mg/kg hydralazine has been studied in three human tumour xenografts (two rectocolic adenocarcinomas and one melanoma) treated with two doses of misonidazole similar to those used in patients (0.1 and 0.2 mg/g). Only a small sensitization was detected using an in vitro colony assay. These results are in marked contrast to the results obtained with rodent tumours. This difference between human tumour xenografts and rodent tumours might be explained by differences in the reduction of tumour blood flow after hydralazine administration (5 and/or 10 mg/kg). Using the laser Doppler technique, the tumour blood flow reduction was 33% and 25% of the control for NA11 and HRT18 tumours, respectively. In contrast, hydralazine induced a 60-70% reduction in blood flow in the murine SCCVII tumour. Using the fluorescent marker Hoechst 33342, the reduction in perfusion was again more pronounced in the murine tumour as compared to the Na11 and HRT18 xenografts. The differences between human tumour xenografts and rodent tumours are not linked to the mouse strain used (nude versus C3H) nor to a tumour bed effect.

Animals↗
PubMed1989

The fate of miniplates in facial trauma and orthognathic surgery: a retrospective study.

The fate of 279 Champy miniplates used routinely as permanent implants over a 5-year-period in the management of maxillofacial trauma and orthognathic surgery has been analysed retrospectively. Trauma patients (62) and orthognathic patients (47) were analysed separately; in each group those patients who had plates removed were compared to the patients with retained plates. This study indicates that the morbidity of retaining plates is within acceptable limits and that the routine removal of plates at 3 months may be unnecessary.

Adolescent↗
PubMed1989

Oxygen enhancement ratio of fractionated regimens in vitro.

The oxygen enhancement ratio (OER) of proliferating and nonproliferating cells grown in vitro was measured using accelerated fractionated regimens. Irradiations were performed either twice daily or three times per day, with a minimum of 6 h between the consecutive fractions. The dose delivered was 2.3 Gy per fraction. Two significant observations were made: (i) the OER of accelerated fractionation regimens for proliferating cells is lower than that obtained from single-exposure experiments at 2.3 Gy (approximately 1.4 vs 2.4, respectively), while for nonproliferating cells it is approximately the same (2.3); (ii) the fractionated regimen does not spare proliferating cells irradiated under hypoxic conditions, and thus the fractionated survival curve lies below the single-exposure curve. For cells irradiated under aerobic conditions or for nonproliferating cells, irradiated under either hypoxic or aerobic conditions, the fractionated survival curve lies above the single-exposure curves as expected.

Animals↗
PubMed1977

Development and size of the teeth of Macaca mulatta.

A cross-sectional sample of 151 skulls from Macaca mulatta of known age and similar rearing in U.S. Primate Centers was analyzed to determine age-related "norms" of stages of development and size of teeth. The stages of development from the follicle of a deciduous incisor in the fetus to completion of the root with apex closed of the permanent third molar were related to age. The age range observed for eruption of each tooth was noted and related to its stage of development. The crown of each erupted tooth was found to be completely developed, but growth of its root continued for a longer, indeterminate period. When a deciduous tooth was exfoliated, the crown of the permanent successor was found to be completed and root growth had begun. Measurements of both mesiodistal and faciolingual diameters and of crown length of the teeth in situ and of total length and root length on roentgenograms were examined for sexual dimorphism. The faciolingual diameter of the deciduous mandibular second incisor and of both second molars showed the greatest sexual dimorphism among both diameters of all deciduous teeth. The mesiodistal and faciolingual diameters of the mandibular premolars were found to be the best dimensions in discriminant functions for identifying sex in the absence of permanent canines.

Age Factors↗
PubMed1976

The density of long limb bones and the percentage ash weight of the skeleton of Macaca mulatta.

The gravimetric density of humeri, radii, femora and tibiae from a series of 274 male and female skeletons of rhesus monkeys, Macaca mulatta, was determined for fetal, young and adult periods. The ages of 171 of the animals were known: they ranged from 57 days of gestation to 13.6 years; the ages of an additional 103 skeletons were estimated. The mean density of the fetal bones was found to increase linearly with age and was higher for males than females, and higher for the superior than for the inferior limb bones. During the young period the pattern of increase in density can be represented by a power-type curve, and the density is significantly higher in females than in males and in superior than in inferior limb bones. The densities of the long limb bones of the adult skeletons show a slight, but not significant, negative trend with increasing age. In this age group the mean densities are higher for males than females and higher for the superior than for the inferior limb bones. The percentage ash weight was determined for the total skeleton and for 21 subdivisions of 23 postnatal skeletons with estimated ages. The skull and long limb bones were found to have higher mean percentage ash weights than the vertebral segments and the sternum. Both the density and the percentage ash weight of the Macaca mulatta skeletons examined exceed those found in our earlier studies of the human skeleton.

Age Factors↗
PubMed1975

Sequential changes in weight of the skeleton and in length of long limb bones of Macaca mulatta.

In a collection of 274 monkeys (Macaca mulatta) the relative weight of the dry, fat-free skeleton, expressed as a proportion of total body weight, increases significantly throughout the gestational period to approximately 6% with only random variation after birth. The weight of the fetal skeleton increases exponentially with age. In the postnatal period the skeletal weight increases asymptotically to adulthood, which is considered to be 6.5 years of age. Equations for estimating skeletal weight are presented. Of four subdivisions of the skeleton, the skul contributes the greatest proportion of total skeletal weight in the fetal stage with the proportion decreasing to adulthood. The contributions of the other subdivisions, postcranial axial, superior limb, and inferior limb, and inferior limb, are nearly equal in the fetal stage, with that of only the inferior limb increasing to adulthood, when it makes up the greatest proportion of total skeletal weight. Until the last third of the gestational period, the humerus is longer than the femur and the radius longer than the tibia. Thereafter, the inferior limbs grow at a faster rate than the superior limbs, resulting in an intermembral index of approximately 95% by birth and less than 90% by adulthood.

Age Factors↗