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S A Thompson

Publications and source records attributed to S A Thompson.

At least 145 records · Page 8Linked to original sources
PubMed1986

Immunocytochemical localization of metallothionein in the rat prostate gland.

Metallothionein (MT), which binds zinc and other metals, was localized within the rat prostatic complex at light and electron microscopic levels utilizing immunocytochemistry. Two groups of mature, male Sprague-Dawley rats were injected with cadmium chloride subcutaneously (2 mg/kg body weight) to induce the synthesis of MT, and were sacrificed 48 h postinjection. From the first group, prostatic tissue from the three lobes was prepared for light microscopy. The indirect peroxidase antiperoxidase procedure was used for MT localization using rabbit anti-MT as the primary antibody. The three lobes of the rat prostate demonstrated a positive reaction for MT, but among the lobes variations in the intensity and localization of the reaction product occurred. Tissues from the second group of animals were prepared for electron microscopy. Using the indirect immunogold labeling technique with anti-MT, MT localization was confirmed in the rough endoplasmic reticulum, secretory vesicles, secretory products, and subepithelial connective tissue. These localizations suggest that MT binds zinc both intra- and extracellularly, where it may function in zinc storage and metabolism.

Animals↗
PubMed1986

Carboxyl-modified amino acids and peptides as protease inhibitors.

Several types of carboxyl-modified amino acids and peptides were prepared in forms having N-terminal modifications (carrier fragments) suitable for one of several representative protease enzymes, and their inhibitory action toward those enzymes were evaluated. The carboxyl modifications (inhibitory units) included (b) CONH2, (c) CSNH2, (d) CN, (e) trans-CH = CHCO2Me, and (f) trans-CH = CHSO2Me. The carrier fragments included NH2(PhCH2)CHX (1), AcNH(PhCH2)CHX (2), H2NCH2CONH(PhCH2)CHX (3), and AcNH(PhCH2)CHCONHCH2X (4). Compounds 1b, 1d, 1e, and 1f were competitive inhibitors of both microsomal and cytosolic leucine aminopeptidase (Ki = 14.8, 67, 61, and 3.7 mM with the former and 14.1, 26.4, 27.3, and 8.8 mM with the latter, respectively). Neither compound 1c nor leucine thioamide had any detectable effect on either enzyme. Compounds 2b-f were also competitive inhibitors toward chymotrypsin (Ki = 13.9, 23.0, 5.3, 30.8, and 29.4 mM, respectively). While 4b, 4c, and 4d were competitive inhibitors of papain (Ki = 4.7, 0.095, and 0.0011 mM, respectively), 4e proved to be an irreversible affinity label (Ki = 0.026 mM and k2 = 0.0018 s-1). Inactivation of papain by 4e was retarded in the presence of 4d and could not be reversed by dialysis. Similarly 3b and 3d were competitive inhibitors of dipeptidyl aminopeptidase I (DPP-I, EC 3.4.14.1) (Ki = 6.2 and 0.0027 mM, respectively), while 3e and 3f were irreversible affinity labels (Ki = 0.22 and 0.18 mM, and k2 = 0.015 and 0.010 s-1, respectively). Inhibition of DPP-I by 3d provides only the second example of a cysteine protease which is strongly inhibited by a nitrile analogue of a specific substrate. Further studies are needed to determine the generality and potential utility of this finding. Compounds 3e, 3f, and 4e exemplify a new class of specific affinity labels for cysteine proteases whose activity probably derives from irreversible Michael addition of the catalytic cysteine to the activated double bond.

Amino Acids↗
PubMed1985

Characterization of the heterogeneity of R3327 rat prostatic tumors derived from single-cell clones.

Prostatic adenocarcinoma is characterized by cellular diversity, which is well demonstrated in the Dunning R3327 rat prostatic adenocarcinoma. This heterogeneity may arise from epigenetic influences, ie, cellular adaptation or selection, and/or from genetic changes. To investigate the question of genetic instability, four tissue culture cell lines were derived from single cells isolated from the uncloned late (UCL) passage of the Dunning R3327H prostate cell culture. Each of these clonally derived tissue cultures was injected into castrated and intact young adult male rats for tumor production. Uncloned early (UCE) and UCL passage tissue cultures were also propagated as solid tumors. Tumors and the cultures from which they were derived were examined for evidence of phenotypic and genetic changes using morphological and cytometric methods. Transmission and scanning electron microscopy revealed only slight differences among the cell cultures. A single population of diploid cells was demonstrated in each of the cell cultures by propidium iodide staining and subsequent flow cytometric measurement of DNA content/nucleus. Tumors of unicellular as well as multicellular origin exhibited extreme heterogeneity of histological features, both among animals as well as within a single tumor. Tumors were surveyed and tissue types were characterized and cataloged. Clone 3 was generally better differentiated than the others; tumors from castrated animals were better differentiated than those from intact animals. Flow cytometry revealed multiple hyperdiploid cell populations that were variable from one sample to another. We concluded that changes in genotype as well as phenotype occurred in the tumors derived from single cells. Some of these changes may have occurred in the cells while still in culture.

Adenocarcinoma↗
PubMed1985

Immunocytochemical localization of tissue-bound oestradiol in rat paracervical ganglion.

The uterine paracervical ganglion (Frankenhauser's ganglion) contains the terminal neurons of the cholinergic sacral parasympathetic, the short adrenergic sympathetic and the peptidergic (vasoactive intestinal polypeptide-containing) nerves of the internal genitalia. Previous studies have shown that either the number of cells or transmitter content of each of these neuronal systems is altered by variations in steroid hormones. Furthermore, our recent study showed that some component of the rat paracervical ganglion was capable of metabolizing [3H]oestradiol to oestrone and the 2-OH and 4-OH forms of oestrone and oestradiol. The present study employs the peroxidase-anti-peroxidase immunohistochemical method to localize oestradiol in rat paracervical ganglia. Specific reaction product was identified in (1) cytoplasm and some nuclei of principal ganglion cells, (2) cytoplasm of large vacuolated ganglion cells, (3) cytoplasm of 'small intensely fluorescent' cells and (4) some nerve fibres in ganglia from animals in oestrus. The cytoplasm of principal neurons and some nerve fibres exhibited specific staining for oestradiol in dioestrus and pro-oestrus. No oestradiol was localized in ganglia excised from animals in metoestrus. Preincubation in oestradiol before fixation was necessary for specific localization of oestradiol; treatment of tissues with oestradiol after fixation was not required. These results are not consistent with binding of oestradiol to the classical oestrogen receptor. The resistance of oestradiol to organic solvent extraction suggests that oestradiol is covalently bound to tissue proteins. Such covalently bound oestradiol has been reported as a by-product of tissue metabolism of oestradiol via P-450 enzymes.

Animals↗
PubMed1985

Differential effects of prolactin on rat dorsolateral prostate and R3327 prostatic tumor sublines.

Many investigators have reported effects of the pituitary hormone, prolactin, on the physiology and biochemistry of the rat prostate gland, particularly the lateral or dorsolateral lobe. The Dunning R3327H is a transplantable rat prostatic adenocarcinoma derived from a spontaneous tumor of the Copenhagen rat dorsolateral prostate. This study describes and compares morphological and physiological effects of prolactin on rat dorsolateral prostate and two sublines of the Dunning tumor. Ectopic pituitary grafts were used to induce chronic hyperprolactinemia in castrated rats receiving androgen supplement to provide a relatively controlled hormonal environment in which the effects of prolactin were maximally and consistently observed. Gravimetric and biochemical analyses, as well as ultrastructural study, provided evidence of prolactin's stimulatory effect on dorsolateral prostate growth and secretory activity. Hyperprolactinemia stimulated the growth of the well-differentiated, androgen-dependent R3327/3219 tumor subline with an increase in weight, volume and the total content of DNA, protein and zinc. There were no changes in tumor morphology. In contrast, the anaplastic androgen-independent R3327/150 tumor subline did not respond to graft-induced hyperprolactinemia. This differential response of the two R3327 tumor sublines attests to the complexity of prolactin's effects on prostatic tissue and to the extent of the deterioration of endocrine control that often accompanies tumor progression. Prolactin binding in the R3327 sublines was studied using immunohistochemical staining and radioligand assay, but produced complex results which raise questions about the discrepancy between hormone binding and biological action of prolactin in prostatic tissues.

Adenocarcinoma↗
PubMed1984

Androgen receptor binding characteristics in the cytosol of the rat dorsolateral prostate gland and the Dunning R-3327 prostatic adenocarcinoma.

The incidence of prostatic cancer is highly correlated with advanced age, and it has been suggested that changes in androgen binding may be important in age-associated alterations in growth regulatory mechanisms of prostatic epithelial cells. In this study the effects of age on androgen binding characteristics in the dorsolateral prostate glands of young and aged Copenhagen rats were determined and the binding properties in the Dunning R3327/130 subline of rat prostatic adenocarcinoma were characterized. Tritium-labeled and nonlabeled methyltrienolone analogs (R1881) were used to study the binding properties of 5 alpha-dihydrotestosterone receptor in the cytosol of tumors and prostate glands. Binding of R1881 was low but specific for the androgen receptor as shown by competition studies in which nonlabeled R1881, 5 alpha-dihydrotestosterone, and testosterone competed successfully with 3H-R1881 for binding sites, but 17 beta-estradiol and low levels of progesterone did not. In Copenhagen dorsolateral prostate, Scatchard analysis suggested a single class of binding sites. In young animals (three to five months) the average binding capacity was 10.36 fmol/mg cytosol protein with a dissociation constant (Kd) of 2.28 nmol/L. The dorsolateral prostate of aged rats (11-16 months) showed no significant difference in specific binding characteristics as compared to the younger age group. Specific binding of 3H-R1881 in R3327/130 tumor was saturable with a single class of high-affinity binding sites having an average binding capacity of 64.77 fmol/mg cytosol protein and a Kd of 2.76 nmol/L. These data show that the tumor had approximately 6.5 times the number of binding sites as did the normal Copenhagen rat dorsolateral prostate gland. However, no age-related changes were detected through 11-16 months of age in the androgen binding characteristics of normal rat dorsolateral prostate gland that could be correlated with the higher concentration of androgen binding sites in the R3327/130 tumor subline.

Adenocarcinoma↗
PubMed1984

Hormonal effects on zinc concentration and morphology of rat lateral prostate gland.

Hypophysectomized rats were injected with prolactin and/or testosterone, and luteinizing hormone (LH) and prolactin and/or follicle-stimulating hormone (FSH). Tissue from the lateral prostate was processed for spectrophotometric determination of zinc and for electron microscopy. Changes in zinc concentration, epithelial height, and morphological characteristics were used to assess the effect of hormonal replacement on functional activity. Although testosterone administration resulted in full restoration of all parameters, there was no evidence of a synergistic effect of prolactin and testosterone. Prolactin alone decreased the zinc concentration and increased the epithelial height compared with control animals, and there was evidence of epithelial hyperplasia. Luteinizing hormone, alone or combined with prolactin or prolactin and FSH, resulted in a marked increase of epithelial height and restoration of morphological features found in intact animals; however, only a slight increase of zinc concentration over control values was elicited. Combined LH and FSH administration reduced epithelial height and zinc concentration compared with the other LH regimes, and there was evidence of cellular degeneration.

Animals↗
PubMed1983

The structure of the bladder neck in male bladder neck obstruction.

A light microscope and neurohistochemical study is presented of full thickness biopsies from the bladder neck of 10 middle-aged males with urodynamically proven bladder neck obstruction. Apart from varying degrees of collagen deposition in seven cases, no abnormality was present in the detrusor and pre-prostatic components of the bladder neck muscles or in the distribution of cholinergic nerve fibres. The normal noradrenergic innervation to the pre-prostatic sphincter was absent in all specimens; this may be age-related.

Adult↗
PubMed1982

Biochemical and immunohistochemical characterization of prolactin binding in rat ventral, lateral, and dorsal prostate lobes.

A radioligand assay and the soluble peroxidase-antiperoxidase (PAP) technique were used to compare ovine and rat prolactin as ligands for the demonstration of prolactin binding sites in rat ventral, lateral, and dorsal prostate lobes. Biochemical techniques were effective in demonstrating prolactin binding sites in ventral prostate with both ovine and rat prolactin; however, binding sites could not be characterized in lateral or dorsal lobes with either ligand. Using the PAP technique, rat prolactin consistently produced a discrete, dense reaction product over binding sites in the Golgi zone of the ventral prostate; ovine prolactin produced a more dispersed pattern of staining throughout the entire supranuclear region of the cells. In ventral prostate, most epithelial cells were immunoreactive when either ligand was used. However, lateral prostate contained fewer densely immunoreactive cells than did ventral prostate, and rat prolactin was more effective in demonstrating these binding sites than was ovine prolactin. Dorsal prostate epithelium was highly immunoreactive for binding of both ligands; however, there was considerably more staining in this lobe that remained after absorption of the antibody with prolactin. These data suggest that the inability to demonstrate prolactin binding sites in the lateral lobe using radioligand assay may have been due to the fewer numbers of binding sites that were diluted below the sensitivity of the assay when a tissue homogenate preparation was used. Noncompetitive binding in the dorsal lobe, as seen in the radioligand assay, coincided with immunocytochemical findings of relatively high nonabsorbable background staining.

Animals↗
PubMed1982

Localization of immunoreactive prolactin in ependyma and circumventricular organs of rat brain.

Immunoreactive prolactin (IMP) has been localized in the male rat brain using the soluble peroxidase-anti-peroxidase (PAP) technique. In normal untreated animals, reaction product was seen in choroid plexus (CP) and in ependymal cells of the ventricular lining with heaviest concentrations of positively staining cells in the 3rd ventricle near the subcommissural organ (SCO), in the lateral ventricles near the subfornical organ (SFO), and in the 4th ventricle near the area postrema (AP). IMP was also present in numerous ependymal cells resembling tanycytes in the cerebral aqueduct, central canal of the spinal cord at the level of the AP, the organum vasculosum of the lamina terminalis (OVLT) and the floor of the infundibular recess. Immunoreactive cells resembling neurons were localized within the substance of the AP, SCO, and OVLT. IMP was also present in fibers of the zona externa of the median eminence and infundibular stalk; a few cells of the pars tuberalis contained reaction product. Hypophysectomized rats and bromocriptine-treated rats exhibited a similar staining pattern except that bromocriptine treatment eliminated IMP from most CP cells. Hypophysectomy, bromocriptine or estrogen treatment enhanced staining for IMP in cells of the pars tuberalis; estrogen treatment or hypophysectomy produced an increase in the number and distribution of immunoreactive cells as well as increased density of reaction product in cells of the medial habenular nucleus. The functional relevance of prolactin in these locations in the brain, the possible routes of transport of prolactin from the pituitary gland to the central nervous system, and the strong suggestion of extra-pituitary sites of synthesis of a prolactin-like hormone are discussed.

Animals↗
PubMed1982

Uptake of prolactin from cerebrospinal fluid in rat brain.

The fate of prolactin in the cerebrospinal fluid was studied by the use of fluorescein labelled prolactin. The distribution was compared to the immunocytochemical distribution of endogenous prolactin. High intensity fluorescence was found in the ependyma of the area postrema, rostral dorsolateral cerebral aqueduct close to the subcommissural organ, and in some cells of the floor of the cerebral aqueduct. This distribution was not seen when excess unlabelled prolactin was injected. The results suggest prolactin uptake from CSF at specific sites which correspond to sites of localization of immunoreactive prolactin.

Animals↗
PubMed1982

Mast cells in interstitial cystitis.

Specific clinical criteria have been used to diagnose interstitial cystitis in 32 patients. The distribution of mast cells in biopsies of the bladder wall from these patients has been compared with that of similar cells in control specimens. A highly significant increase (P less than 0.001) in the number of mast cells within the detrusor muscle bundles has been demonstrated in 27 of these patients. This mast cell infiltration is widespread throughout the detrusor muscle and is not confined to the ulcerative lesions seen cystoscopically. Histological estimation of mast cells is of value, therefore, in establishing the diagnosis of interstitial cystitis, and may be particularly helpful in equivocal cases. The relationship between mast cell infiltration of the detrusor muscle bundles and the aetiology of the disease remains to be determined.

Cell Count↗
PubMed1981

A comparative study of the human external sphincter and periurethral levator ani muscles.

Specimens from the human male and female external urethral sphincter and the periurethral levator ani muscle have been examined using histochemical and electron microscopic techniques. In both sexes the external sphincter consists of a single population of type I (slow twitch) fibres with a mean diameter of 17.47 +/- 0.7 micrometers in the absence of muscle spindles. In contrast, the periurethral levator ani possesses muscle spindles and the constituent fibres form a heterogeneous population of type I and type II (fast twitch) fibres, with mean diameters of 45.5 +/- 0.8 micrometer and 59.5 +/- 3.4 micrometers respectively. These findings indicate that the external urethral sphincter is functionally adapted to maintain tone over prolonged periods and may be of considerable importance in producing active urethral closure during continence. The anatomical location and fibre characteristics of the levator ani muscle suggest that these fibres actively assist in urethral closure, particularly during events which cause elevation of intra-abdominal pressure. In view of the differences in fibre characteristics between the external urethral sphincter and the levator ani, EMG activity recorded from a single site in the levator ani may not be representative of the functional status either of other levator ani muscle fibres or of the external urethral sphincter.

Adenosine Triphosphatases↗
PubMed1981

Effect of dietary fiber sources on tissue mineral levels in chicks.

Dietary fiber may influence mineral status of chicks. Wheat bran, corn bran, soy bran, oat hulls, rice bran, and cellulose, were formulated into diets and fed to chicks for 4 weeks. Fiber-added diets contained additional 6% dietary fiber from the fiber sources. Body weights and feed intakes were recorded. Livers and tibias were analyzed for copper, zinc, iron, manganese, and magnesium. The rice bran diet resulted in significantly lowered body weights, feed intakes, and tibia concentrations of zinc, iron, and manganese. The other fiber-added diets did not produce significantly different values for the parameters examined. Dietary analyses showed that the rice bran diet did not have extremely high fiber levels as compared to the other diets. Addition of rice bran contributed the highest amount of phytic acid of all the fiber sources at 1.3% of the diet. It was concluded that when included at 6% of the diet, most fibers did not influence growth or tissue mineral levels. However, the addition of rice bran to the diet reduced body growth and deposition of zinc, iron, and manganese in tibias. It is possible that one fiber source may be beneficial while another is detrimental to nutritional status.

Animals↗
PubMed1980

Ultrastructural observations on the cell surface of the intestinal epithelium of the nematode, Ascaris suum. Nature of the electronegative charge.

The intestinal epithelium of Ascaris suum consists of a single layer of tall columnar epithelial cells that rest on a thick basal membrane in contact with the pseudocoelomic cavity. Experiments were conducted on glutaraldehyde-fixed tissue to ascertain the nature of the electronegative charges associated with both the apical microvillar surface and basal membrane. A strong electronegative charge was demonstrated on the microvillar surface and basal membrane with ruthenium red and cationic ferritin staining. The ionic nature of ferritin binding was demonstrated with poly-L-lysine, a polycation that interacts with anionic groups on the membrane and thus blocks the subsequent binding of ferritin. Tissue thus treated was devoid of reaction product. Methylation with diazomethane completely abolished staining. Since the stronger acidic groups of sulfates or phosphates would not be protonated under the conditions employed in this study, and therefore susceptible to methylation, staining by ferritin is thought to be due to its interaction with carboxyl groups. Prior enzymatic treatment of tissue with neuraminidase or phospholipase C had no effect on subsequent ferritin binding. Tissue exposed to colloidal iron at various pH values showed maximal reactivity at a pH of 2.5 or above. Above pH 2.5, the dissociation of protons from free carboxyl groups of protein-bound amino-acid residues with pK's of 3.8 and 4.2 would be maximal, and the ionized carboxyl groups are then available to interact with iron micelles. These results suggest the presence of weaker acidic groups, such as the carboxyl groups of acidic amino acids or uronic acid residues. The stronger acidic groups of sialic acid and the esterified sulfate groups, if present, contribute only minimally to overall staining. These results demonstrate that a high electronegative charge density exists, despite the apparent lack of sialic acid. Staining is believed to be due to carboxyl groups of acidic amino acids and/or carboxyl groups or uronic acid residues.

Animals↗