Biomedical subjects

W P Ireland

Publications and source records attributed to W P Ireland.

12 recordsLinked to original sources

PubMed1992

Quantitative regional variation in the expression of major histocompatibility class II antigens in enterocytes of the mouse small intestine.

The qualitative and quantitative expression of major histocompatibility class II antigens was investigated in the absorptive epithelium of the duodenum, jejunum, and ileum from mice of C3H/He (H-2k haplotype) and C57BL/6 (H-2b haplotype) strains by peroxidase-antiperoxidase labelling and image analysis. Immunohistochemical labelling revealed that the expression of class II antigens was greatest in the ileum and decreased proximally towards the duodenum. The villus epithelium of the duodenum showed a granular staining pattern in the apices of some cells. In the jejunum, an increased expression was demonstrated in the apical and basal cytoplasm of all cells covering the villus. Cells at the tip of the villus, in addition, showed staining of the lateral surfaces. Ileal enterocytes demonstrated the most intense immunostaining appearing in the cytoplasm and along baso-lateral surface membranes. Quantitative analyses confirmed that a highly significant (p less than 0.0001) difference in expression of class II antigens occurred in the three regions of the small intestine, which corroborated the qualitative findings. This regional variation of class II molecules by the absorptive epithelium may influence regional differences in antigen presenting functions and immune responsiveness to ingested antigens.

Animals↗

PubMed1991

Statistical evaluation of dendritic growth models.

A mathematical model (Kliemann, W. 1987. Bull. math. Biol. 49, 135-152.) that predicts the quantitative branching pattern of dendritic tree was evaluated using the apical and basal dendrites of rat hippocampal neurons. The Wald statistic for chi 2-test was developed for the branching pattern of dendritic trees and for the distribution of the maximal order of the tree. Using this statistic, we obtained a reasonable, but not excellent, fit of the mathematical model for the dendritic data. The model's predictability of branching pattern was greatly enhanced by replacing one of the assumptions used for the original method "splitting of branches for all dendritic orders is stochastically independent", with a new assumption "branches are more likely to split in areas where there is already a high density of branches". The modified model delivered an excellent fit for basal dendrites and for the apical dendrites of hippocampal neurons from young rats (30-34 days postpartum). This indicates that for these cells the development of dendritic patterns is the result of a purely random and a systematic component, where the latter one depends on the density of dendritic branches in the brain area considered. For apical dendrites there is a trend towards decreasing pattern predictability with increasing age. This appears to reflect the late arrival of afferents and subsequent synaptogenesis proximal on the apical dendritic tree of hippocampal neurons.

Animals↗

PubMed1991

Evaluation of the instantaneous centers of rotation of the stifle before and after repair of torn cruciate ligament by use of the over-the-top technique in dogs.

Seven dogs with torn cruciate ligament were used to evaluate the "over-the-top" repair procedure, using instantaneous center of rotation (ICR). Normal and cruciate-torn stifles of dogs were radiographed before surgery, using an image intensifier videotape system. The injured stifle was reradiographed 6 weeks after surgery. Images of the stifles were photographed from video monitor. Photographs were analyzed by a digitizer hooked to a computer to find the ICR at various angles. Data were analyzed, using multivariate analysis of variance. Relative to those of normal stifles, ICR of the damaged stifles were located significantly (P less than 0.05) proximal and caudal. After surgery, the ICR were still proximal and caudal, but not significantly so. We conclude that the cruciate-torn stifle deviates significantly from normal and that such deviation is restored to normal limits by use of the over-the-top procedure.

Animals↗

PubMed1990

Correlation between cellular changes in supraoptic and paraventricular nuclei and water-drinking in neuroleptic-treated rats.

The neuroleptics haloperidol and thioridazine were injected intraperitoneally in rats for 81 days. During this time the rats' water consumption was measured. Drug-treated animals drank significantly less water for the first 40 days of the experiment only. On day 82 the rats were perfused for electron microscopy. The rat's paraventricular and supraoptic nuclei were embedded, sectioned, stained for electron microscopy and viewed for morphological change. There were significantly more darkly staining neurons in the haloperidol-treated rats than in control rats. Thioridazine-treated rats had more dark neurons but the difference was not significant. These dark cells had the appearance of highly stimulated neurons. Some appeared to be degenerating.

Animals↗

PubMed1990

Structure and organization of the subepithelial microvasculature in the canine nasal mucosa.

To quantitatively characterize the epithelial microvasculature in the transitional nasal mucosa of the dog, septal, dorsal conchal, and ventral conchal tissues were prepared for light microscopy. Subsequent to the drilling of orientation holes perpendicularly into the epithelium, serial 1.0-micron sections were cut parallel to the epithelial plane. A computerized data acquisition system was used in which the sections were aligned and the lumen/wall interfaces of capillaries digitized. Information stored in the program included the position of capillaries, their diameter, their major axis length, and the angle between their major axis and the X axis of the coordinate system. The intraepithelial capillary loops constituted 9% of the epithelial volume, and had a surface area of 31.18 mm2/mm3 of epithelium, and a length of 1055 mm/mm3 of tissue. Their diameters ranged from 9.1 to 11.3 microns for the three tissues sampled. The distances between afferent and efferent limbs of capillary loops were 4.4, 4.5, and 13.8 microns for nasal septum, alar fold, and dorsal concha, respectively. Additional analyses indicated that capillary loops were neither arranged in rows nor oriented to airflow. Rather than conducting heat to the luminal surface, the primary function of these vessels may be to transport cells and/or cytokines to and from a specialized epithelium, one that is adapted to metabolizing contaminants deposited during breathing.

Analysis of Variance↗

PubMed1990

Taste bud density in circumvallate and fungiform papillae of the bovine tongue.

Taste bud quantitation may provide useful parameters for interspecies comparisons of the gustatory system. The present study is a morphometric analysis of bovine taste papillae. Circumvallate and fungiform papillae from six bovine tongues were serially sectioned and, following staining, analyzed. Circumvallate papillae were found to have a mean volume of 3.66 +/- 2.82 mm3, a mean number of taste buds per papilla of 445 +/- 279, and a mean taste bud density of 155 +/- 112 buds/mm3. Values for lateral fungiform papillae for the same three parameters were 0.384 +/- 0.184 mm3, 13.2 +/- 13.4, and 40.8 +/- 46.6 buds/mm3, respectively. Values for dorsal fungiform papillae were 0.438 +/- 0.246 mm3, 4.39 +/- 4.78, and 14.0 +/- 17.1 buds/mm3, respectively. Circumvallate papillae were found to have a significantly greater volume, number of taste buds per papilla, and taste bud density than either type of fungiform papilla. These data should serve as background for biochemical, endocrinological, or neurological studies involving the bovine tongue.

Animals↗

PubMed1989

Pattern conserving data structure and algorithms for computations on dendritic trees.

The linked list is offered as a pattern conserving data structure, useful for storing neuronal dendritic trees. A BASIC language algorithm is described. Modifications of this algorithm for building linked lists, graphing dendritic trees, and tarry ordering trees are presented. Brief mention is made of the last in first out stack as a alternative data structure for computations on dendritic trees.

Algorithms↗

PubMed1988

Mathematical means to allow computer calculation of stereotaxic settings.

Stereotaxic instruments have wide use in neuroscience research. In certain of these machines the electrode can be introduced at an angle as well as perpendicularly. Computation of instrument settings to place the electrode in the desired location is the problem this paper addresses. Mathematical formulae are presented that allow a computer to calculate instrument settings given coordinates and angles read from a stereotaxic atlas.

Animals↗

PubMed1987

Ultrastructure and stereology of leukocytes and platelets of normal foxes and a fox with a Chediak-Higashi-like syndrome.

Peripheral blood leukocytes and platelets from five normal foxes (Vulpes vulpes) and a fox with phenotypical characteristics of Chediak-Higashi syndrome (CHS) were examined by electron microscopy. Lymphocytes, monocytes, neutrophils, eosinophils, and platelets from the affected fox contained giant membrane-bound granules that resembled lysosomes. In eosinophils and neutrophils from the affected fox and a normal fox, relative cell volume occupied by granules and number of granules per unit area were calculated. Relative cell volume occupied by granules was the same in both foxes, but there were significantly fewer granules per unit area in the affected fox. This result is consistent with the idea that the giant granules arose from fusion of pre-existing, normal-sized granules, as occurs in CHS. In platelets from the affected fox, no osmiophilic granules were seen. Our findings agree with those from studies of CHS-affected blood cells in other species.

Animals↗

PubMed1986

Location of the instantaneous center of joint rotation in the normal canine stifle.

Locations of 3 instantaneous centers of joint rotation (ICR) were found in the stifles of 6 healthy dogs. A novel algorithm, verified by computer simulation, was used to determine ICR from radiographs. Comparisons of ICR locations were made between flexion and extension, between left and right limbs, and between living and dead dogs, using analysis of variance. All stifles were examined for evidence of lesions, but all were normal. The normal location of the ICR in the stifle is near the joint surface, indicating that there is a predominantly rolling type of motion. As the limb flexes, the ICR moves caudally; as the limb extends, the ICR moves cranially. Significant differences in ICR position were not found between left and right limbs or between living and dead dogs. The average ICR position was significantly more caudal during extension than it was during flexion. Knowing the normal ICR position is a preliminary to diagnosing joint abnormalities, using the ICR.

Animals↗

PubMed1985

Effects of halothane on the development of rat brain: a golgi study of dendritic growth.

Dendritic growth was studied in rats exposed to halothane in utero for the entire gestation period and 60 days after birth. The exposure conditions were control, intermittent halothane (25 +/- 5 ppm or 100 +/- 5 ppm, 8 h/day, 5 days/week), or continuous halothane (25 +/- 5 ppm, 24 h/day, 7 days/week). Dendritic growth in terms of branch numbers and length was most advanced in the control groups, followed by those groups exposed to 25 +/- 5 ppm halothane intermittently, 25 +/- 5 ppm halothane continuously, and 100 +/- 5 ppm halothane intermittently. The latter two exposure conditions exerted identical effects on dendritic growth. The order of this dendritic growth level established at 5 postnatal days remained the same throughout the first 95 postnatal days in both the entorhinal cortex and subiculum. The effect of halothane on dendritic growth appeared to be enduring, and the delay in the initial dendritic growth caused by halothane was not compensated for by an increased rate of dendritic growth.

Animals↗

PubMed1985

Dendritic alterations in chronic animals with experimental neurofibrillary changes.

Dendritic changes were quantitated in the cerebral cortex and subiculum of rabbits injected with aluminum tartrate for 90 days (5 days/week) at 100, 200, and 300 days after the last injection of aluminum. Both apical and basal dendrites of the cerebral cortex and subiculum responded similarly to aluminum tartrate. The dendrites were fewer and shorter in the animals examined at 200 and 300 days postinjection of aluminum tartrate. Such dendritic changes were more prominent at longer postinjection times and in dendrites that were more peripheral from the cell body. Aluminum-induced changes in apical dendrites were more prominent in the subiculum than in the cerebral cortex. Aluminum-induced changes in basal dendrites, however, were more prominent in the cerebral cortex than in the subiculum. The results suggest a time delay between the initial accumulation of neurofibrillary changes and the subsequent loss of peripheral dendritic branches, which appears to be long-lasting.

Animals↗