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Biomedical subjects

J A Chandler

Publications and source records attributed to J A Chandler.

At least 19 recordsLinked to original sources
PubMed1987

Cell proliferation studies in rat prostate. I. The proliferative role of basal and secretory epithelial cells during normal growth.

In the prostates of rats ranging from 10 days to 8 months of age, the proliferative activity of basal and secretory epithelial cells was studied. No clear evidence was found that basal cells alone represented the proliferative compartment, or that they were responsible for the replacement of secretory cells during normal turnover. Cell kinetic and morphological evidence indicated that basal and secretory cells were self-replicating cell types with discrete functions.

Animals↗
PubMed1987

Ultrastructure and immunohistochemistry of the lateral prostate in aged rats.

Ultrastructural, histological, and immunohistochemical studies were performed on lateral prostates of 1) aged rats from different strains, 2) rats permitted different levels of sexual activity, and 3) castrated rats. Antibodies against the following proteins were used as immunohistochemical markers: SVS II from seminal vesicle, LP 28 from lateral prostate, acid phosphatase isoenzymes from ventral prostate, transglutaminase from coagulating gland, and a commercial monoclonal antibody against cytokeratin. SVS II is a marker of lateral prostatic secretion, while immunoreactions to LP 28 and acid phosphatase (pI 7.1) were cytoplasmic. In aged animals the amount of intracellular secretion is decreased, and focally metaplastic transformation can be visualized by using immunohistochemical markers. Epithelial ultrastructure varied considerably with experimental conditions. Intensive sexual activity resulted in increased polymorphism and increased number of secretory granules within the glandular cells, while castration was followed by a rapid loss of secretory material. Also, in rats older than 10 months, a reduction in the number of secretion granules was common. The epithelium developed a positive immunoreaction to transglutaminase antibodies that were not observed in juvenile glands. Cells, presumably macrophages, which had an intense immunoreactivity for transglutaminase, were increased in number both within and outside the prostatic acini of aged rats. The possible interaction between secretory SVS II, a substrate of transglutaminase, the release of this enzyme from macrophages or its reflux from coagulating glands, the spontaneous cellular exfoliation that is due to decreased androgen levels, and dietary noxae may be of importance in the development of lateral prostatic nonbacterial inflammation in aged rats.

Acid Phosphatase↗
PubMed1987

Cell proliferation studies in the rat prostate: II. The effects of castration and androgen-induced regeneration upon basal and secretory cell proliferation.

The changes over short and prolonged periods (up to three months) after castration on the proliferative activity of basal and secretory epithelial cells in the rat prostate were studied. Although castration induced widespread apoptosis of the secretory cells, no compensatory hyperplasia of the basal cells in response to this was noted. Instead, observations of the cell kinetics and ultrastructure suggested that both the basal and secretory cells entered a quiescent state as a result of castration. The proliferative potential of secretory cells was not diminished up to three months after castration. During androgen-induced regeneration of the prostate the pattern of basal and secretory cell proliferation was found to be similar to that observed during normal growth, although it was more rapid and of shorter duration.

Animals↗
PubMed1985

The effects of estradiol-17 beta on the ultrastructure and subcellular distribution of zinc in the prostatic epithelium of castrated rats.

Male Sprague-Dawley rats, previously castrated for a 7-day period, were maintained on either a low or high dose of estradiol-17 beta for 3 days. Some areas of the prostatic epithelium in the lateral lobe exhibited the ultrastructural characteristics of the untreated, intact animals in response to the small dose of estrogen. The ventral lobe by comparison was not similarly affected. This stimulation in the lateral prostate was not reflected by comparable changes in the subcellular distribution of zinc.

Animals↗
PubMed1985

X-ray microanalysis of biological tissues--an examination of comparative specimen preparation techniques using prostatic tissue as a model.

A number of reproductive tissues have been investigated by X-ray microanalysis for a large number of elements. These elements occur both free and with many different forms of binding to tissue proteins and cellular constituents. The prostate tissue studied here represents a glandular tissue with both parenchymal and stromal components having different cell types. While no general rule can be applied to the preparative technique for all tissues, it would seem that of all the methods examined here freeze substitution or the use of dehydration fluids combined with subsequent embedding offer the most promising compromise between cryoultramicrotomy and aqueous fixation.

Animals↗
PubMed1984

Endogenous elements in the prostate. An X-ray microanalytical study of freeze-dried frozen sections and histochemical localization of zinc by potassium pyroantimonate.

Freeze-dried frozen sections prepared from unfixed rat lateral prostate were examined by X-ray microanalysis in an attempt to establish the in vivo distribution of endogenous ions. Poor morphological resolution was a limiting factor in the analysis of subcellular regions of the tissue. Glutaraldehyde fixation prior to cryo-sectioning resulted in considerable loss of elements. The results are discussed and compared with those obtained from ultrathin sections of tissue treated with potassium pyroantimonate. Using the latter method, it was possible to demonstrate a subcellular distribution pattern for the element zinc and to correlate the metal with specific organelles. It is considered that, unlike a number of other tissues, the rat prostate does not lend itself readily to cryoultramicrotomy as a preparative regime.

Animals↗
PubMed1984

Clinical evaluation of patients eight to nine years after placement of removable partial dentures.

Removable partial dentures, constructed following principles outlined in this study, provided reasonable service for an 8- to 9-year period for patients who were wearing them. The oral hygiene of the patients was less than ideal. Few teeth were lost by patients in the study. There were no significant differences in caries incidence, changes in sulcus depths, tooth mobility, or alveolar bone loss between patients who were wearing their dentures and those who were not. There were increased levels of gingival inflammation seen in regions covered by the removable partial dentures and in gingivae apical to clasp arms. Other than these findings, there seemed to be no direct evidence that the removable partial dentures were causing dental or periodontal breakdown.

Adult↗
PubMed1983

Ultrastructural and analytical studies on the prostate of castrated rats.

Rat lateral and ventral prostate tissue was studied using ultrastructural and analytical techniques in adult animals castrated for periods of 3 to 20 days. As in previous reports involution of the prostatic epithelium following testosterone deprivation resulted in alterations of the amount, distribution, and conformation of the endoplasmic reticulum, Golgi, and lysosomes in addition to some nuclear changes. Although the fundamental changes were similar in both lobes there were specific effects on the individual lobes. Reductions in the subcellular levels of zinc were more pronounced in the lateral prostate, particularly with respect to the secretory and stromal concentrations of the metal. Despite low concentrations of circulating testosterone, secretory activity was still evident after a 20-day castration period and would appear to reflect a different sensitivity in the lateral lobe to the lowered testosterone level or stimulation by other hormones when compared to the ventral lobe. The significance of the subcellular distribution pattern of zinc during the experimental periods is discussed in relation to the possible functional significance of the metal in prostatic tissue.

Animals↗
PubMed1983

Effects of androgens on the ultrastructure and subcellular zinc distribution in the prostatic epithelium of castrated rats.

Sprague Dawley rats were maintained on testosterone propionate or 5 alpha-dihydrotestosterone for 3 days following bilateral orchidectomy for a 7-day period. Ultrastructural examination showed only partial recovery of the prostatic epithelium with testosterone propionate while 5 alpha-dihydrotestosterone caused the lateral and ventral lobes to revert to the appearance of control tissues. The latter metabolite induced greater stimulation of the prostate evidenced by increased mitotic division of the epithelial cells and an increased number of basal cells exhibiting ciliary formation was observed. Zinc concentrations in subcellular regions of both lateral and ventral prostate lobes were affected by the two androgens. Testosterone propionate was most effective in elevating zinc in the lateral lobe, particularly within the secretory components. In the ventral lobe both androgens caused an increase in subcellular zinc concentrations above control levels. The increase of nuclear and nucleolar zinc was related to the increase in nuclear activity and cellular response to the androgen administration.

Androgens↗
PubMed1983

The distribution of zinc in the prostate of rhesus and cynomolgus monkeys determined by electron microscopy and x-ray microanalysis.

The distribution of zinc in the prostate of the mature rhesus monkey is described. High levels of zinc were located in the nuclei of epithelial and basal cells in both lobes of the gland, while elevated concentrations of the metal were also found in secretory granules and along lateral cell membranes. A similar zinc distribution pattern was observed in the 2 lobes of the gland, but in general organelles in the cranial region had a higher content of the metal. In whole tissue, however, a 15 times greater zinc content was measured in the caudal lobe. This difference could be explained in terms of the high levels of the metal present in secretory granules and luminal secretion in the caudal lobe. A similar ultrastructural appearance and distribution of zinc was observed in the prostate of the cynomolgus monkey (Macaca fascicularis).

Animals↗
PubMed1983

Electron radiation damage in thin specimens prepared for X-ray microanalysis by cryoultramicrotomy, freeze substitution and normal resin embedding.

Analysis of biological tissue is ultimately limited by the transformation of elemental composition under the influence of the electron beam. Specimen erosion depends on elemental composition and molecular structure, analytical conditions and specimen temperature. Studies reported here indicate a variability in elemental and mass loss for various preparations of thin sections. With careful choice of specimen preparation techniques and analytical operating conditions, mass and element losses from the specimen can be minimised.

Animals↗
PubMed1981

The ultrastructure of dog epididymis.

The ultrastructure of the epididymal duct and ductuli efferentes in the dog has been studied by electron microscopy. The epididymidis can be separated into the classical divisions of caput, corpus and cauda epididymidis on the basis of general morphology and ultrastructure. The ductuli efferentes have a low epithelium with pronounced cilia at the apices of cells and appear to provide primarily a transport role for spermatozoa. In the epididymis proper the caput region is characterized by an extremely large Golgi apparatus with large numbers of lysosomes and nuclear inclusions. Secretory activity appears to be most common in the corpus region. Absorption and secretion are most active in the first two segments while in the cauda epididymidis the long-term storage of spermatozoa in the lumen is associated with many dense crystalline bodies formed in the epithelial cells within the Golgi apparatus and possibly deriving from absorbed macromolecular material from the lumen. The theory of whole sperm cell resorption by the epididymal duct is not supported by this study.

Animals↗
PubMed1980

Application of x-ray microanalysis in reproductive physiology.

Sperm, testis, prostate, epididymis and uterus have all beeen examined by X-ray microanalysis in the electron microscope. Specimen preparation has included air drying of whole cells, fixation, histochemical treatment, cryoultramicrotomy and freeze substitution of soft tissues, and micropuncture and pipetting of microdroplets from tissue fluids. Early analyses involved the study of thick samples using the electron probe microanalyser (EPMA) with wavelength dispersive spectrometry (WDS). More recently energy dispersive spectrometers (EDS) have been coupled to EMMA, TEM, SEM and STEM instruments to study these tissues. Although spatial resolution and sensitivity of analysis have greatly improved recently, specimen preparation remains a major limitation to the successful analysis of physiological levels of elements in reproductive tissues. A review of comparative methods of analysis and specimen preparation procedures is given for tissues of male and female species.

Animals↗
PubMed1979

Histochemical localization of glycosidases in dog epididymis.

The histochemical localization of five glycosidases was studied in the epididymis of mature dogs. beta-Galactosidase showed a distinct to strong reaction in the epithelium of the ductuli efferentes and throughout the whole length of the ductus epididymidis. beta-N-Acetylglucosaminidase reactivity was weak in the initial segment, but increased significantly in the middle and terminal segment. The maximum beta-glucuronidase activity was found in the ductuli efferentes and in the initial segment. The alpha-mannosidase reaction was weak in all segments except the middle segment where a distinct activity was seen. With the method employed, no alpha-fucosidase activity could be detected. The physiological role of the glycosidases in the epididymis is discussed briefly.

Acetylglucosaminidase↗
PubMed1979

Principles of X-ray microanalysis in biology.

Progress in biological X-ray microanalysis has been limited in recent years by specimen preparation procedures. Instrumentation and high levels of sensitivity for low concentrations are well developed for a large number of biological applications but reliable preparation of samples in the thick or thin form has yet to be establisehd. In addition the possible damage of specimens by the electron probe has been incompletely studied in the majority of applications. In this review the basic principles of X-ray production, design and operation of X-ray detectors, quantitative procedures for thick and thin samples, analytical operation of the microscope, and current specimen preparation techniques are briefly described with the aim of highlighting weaknesses and discussing recent developments in each field.

Animals↗
PubMed1978

The incidence of mosquitoes feeding on mothers and babies at Kisumu, Kenya.

Blood fed mosquitoes were collected inside four bed nets in which mother/child pairs, having different haptoglobin types, slept. The bloodmeals were analysed by gradient gel electrophoresis to determine on which person the mosquitoes had fed. The results suggest that the mothers are fed on much more than babies by both Anopheles gambiae s.l. and Culex fatigans. In one hut at least 15.2 per cent of the mosquitoes had taken all or part of their bloodmeal elsewhere. A greater number of double feeds were detected from engorged Cx. fatigans (12.6%) than An. gambiae s.l. (2.7%).

Anopheles↗
PubMed1977

The subcellular distribution of zinc in dog prostate studied by x-ray microanalysis.

X-ray microanalysis of zinc in ultrathin sections of dog prostate was performed by electron microscope microanalysis using the potassium pyroantimonate method of preparation. Prostates of both mature and immature dogs were examined and the metal was found to be localised primarily in the nucleolus, nuclear chromatin and secretory granules of epithelial cells. Differences in zinc concentrations were observed between mature and immature tissues, particularly in the nuclear chromatin. The metal was also incorporated into epithelial secretions, lysosomes and fibromuscular stroma. Variable binding of zinc to tissue components was revealed by a combination of histochemical precipitation and subcellular analysis.

Animals↗