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R S Redman

Publications and source records attributed to R S Redman.

At least 19 recordsLinked to original sources
PubMed2000

Immunohistochemical localization of carbonic anhydrases I, II, and VI in the developing rat sublingual and submandibular glands.

Carbonic anhydrase has been localized to the acini and ducts of mature rat salivary glands. This enzyme has been associated with ion transport, a prominent function of striated and excretory ducts in salivary glands, suggesting that it might be used as a marker of ductal differentiation. The purpose of this study was to immunohistochemically document developmental changes in carbonic anhydrase in the ducts of the rat sublingual and submandibular glands. Immunohistochemistry was performed with antibodies to human carbonic anhydrase isoenzymes I, II and VI on sections of sublingual and submandibular glands from rats at representative postnatal developmental ages. Reactions were weak in the ducts of both glands at 1 day, then progressively increased. By 42 days, reactions had the adult pattern of virtually none in the mucous or seromucous acini, moderate to strong in the striated and excretory ducts, and none to weak in the intercalated ducts. Weak to moderate reactions were observed in the granular convoluted tubules of the submandibular gland as they became recognizable at age 42 days. Reactions to carbonic anhydrase I and II antibodies also increased from none (1 day) to modest (42 days) in the demilunes of the sublingual gland. The order of reaction intensity of the antibodies was II > I > VI. When localized via these anti-human antibodies, carbonic anhydrase is a useful marker of the functional differentiation of the striated and excretory ducts of the developing rat sublingual and submandibular glands.

Animals↗
PubMed1999

Enzyme histochemical localization of Na(+),K(+)-ATPase and NADH-DE in the developing rat parotid gland.

Information on ductal differentiation in the developing rat parotid gland is sparse. Striated and excretory ducts are rich in a number of enzymes related to ion movement. The objective of this investigation was to delineate histochemically the chronology of two of these, ouabain-sensitive Na(+),K(+)-ATPase and NADH-DE, in the developing rat parotid gland. Parotid glands were excised from rats at representative ages from 20 days in utero to 42 days. Enzyme histochemistry was performed on air-dried frozen sections. For Na(+), K(+)-ATPase, some sections also were fixed in phosphate-buffered formalin. Ouabain blocked Na(+),K(+)-ATPase activity, and neither enzyme reacted without substrate. Weak Na(+),K(+)-ATPase reactions were initially seen in unfixed sections at 1 day, and increased steadily to the adult pattern of strong (concentrated basolaterally) in striated ducts and excretory ducts, respectively, and weak to modest (diffuse) in acini and intercalated ducts at 28 days. In fixed sections, localization was sharper but the reaction was somewhat reduced. NADH-DE was modest in terminal buds and ducts before birth, then progressively changed to the adult pattern of weak in acini and intercalated ducts and strong (concentrated basally and luminally) in striated and excretory ducts at 28 days. As demonstrated by enzyme histochemistry of Na(+),K(+)-ATPase and NADH-DE, differentiation of rat parotid striated ducts and excretory ducts occurs mainly between birth and 28 days. Anat Rec 256:72-77, 1999. Published 1999 Wiley-Liss, Inc.

Animals↗
PubMed1999

Effect of 24 hours light on circadian rhythms of secretory enzymes and morphology of rat von Ebner's glands.

Von Ebner's glands of the rat are minor salivary serous glands in the posterior portion of the tongue. They secrete two digestive enzymes, lingual lipase and amylase. In this investigation, circadian rhythm in feeding was established under a normal 12 h light/12 h dark cycle, with the rats eating primarily during the dark period. At lights on, the size of the acinar cells and the area of the inclusive secretory granules, and the amount of digestive enzyme activity (lingual lipase and amylase) remaining in the gland was significantly less than in the mid-afternoon, after very little daylight food consumption. However, after 7 days of continuous light the circadian rhythm was altered: the food consumption during the normal night-time hours (5 p.m. to 8 a.m.) went from 88% of total 24 h food consumption to 45%, and during normal daylight hours (8 a.m. to 5 p.m.) from 12% to 55%. These changes were correlated with histometric findings of a near reversal of the areas of acinar cells and secretory granules of a.m. and p.m. samples under continuous light. Lingual lipase activity in the glands went from 35% under 12 h light to 61% under continuous light in the a.m. and from 65% to 39% in the p.m. Amylase activity also showed nearly a reversal in activity remaining in the gland, from 36% at 12 h light to 58% at 24 h light in the a.m. and 64% to 41% for the p.m. samples. These results indicate that the von Ebner's glands of the rat have a circadian rhythm of secretion and storage of secretory proteins that is subject to light entrainment similar to that seen in other exocrine glands such as the parotid and pancreas.

Amylases↗
PubMed1999

Fungi from geothermal soils in Yellowstone National Park.

Geothermal soils near Amphitheater Springs in Yellowstone National Park were characterized by high temperatures (up to 70 degrees C), high heavy metal content, low pH values (down to pH 2.7), sparse vegetation, and limited organic carbon. From these soils we cultured 16 fungal species. Two of these species were thermophilic, and six were thermotolerant. We cultured only three of these species from nearby cool (0 to 22 degrees C) soils. Transect studies revealed that higher numbers of CFUs occurred in and below the root zone of the perennial plant Dichanthelium lanuginosum (hot springs panic grass). The dynamics of fungal CFUs in geothermal soil and nearby nongeothermal soil were investigated for 12 months by examining soil cores and in situ mesocosms. For all of the fungal species studied, the temperature of the soil from which the organisms were cultured corresponded with their optimum axenic growth temperature.

Acremonium↗
PubMed1999

Radiation-induced progressive decrease in fluid secretion in rat submandibular glands is related to decreased acinar volume and not impaired calcium signaling.

The mechanism(s) of radiation-induced salivary gland dysfunction is poorly understood. In the present study, we have assessed the secretory function (muscarinic agonist-stimulated saliva flow, intracellular calcium mobilization, Na+/K+/2Cl- cotransport activity) in rat submandibular glands 12 months postirradiation (single dose, 10 Gy). The morphological status of glands from control and irradiated rats was also determined. Pilocarpine-stimulated salivary flow was decreased by 67% at 12 months (but not at 3 months) after irradiation. This was associated with a 47% decrease in the wet weight of the irradiated glands. Histological and morphometric analysis demonstrated that acinar cells were smaller and occupied relatively less volume and convoluted granular tubules were smaller but occupied the same relative volume, while intercalated and striated ducts maintained their size but occupied a greater relative volume in submandibular glands from irradiated compared to control animals. In addition, no inflammation or fibrosis was observed in the irradiated tissues. Carbachol- or thapsigargin-stimulated mobilization of Ca2+ was similar in dispersed submandibular gland cells from control and irradiated animals. Further, [Ca2+]i imaging of individual ducts and acini from control and irradiated groups showed, for the first time, that mobilization of Ca2+ in either cell type was not altered by the radiation treatment. The carbachol-stimulated, bumetanide-sensitive component of the Na+/K+/ 2Cl- cotransport activity was also similar in submandibular gland cells from control and irradiated animals. These data demonstrate that a single dose of gamma radiation induces a progressive loss of submandibular gland tissue and function. This loss of salivary flow is not due to chronic inflammation or fibrosis of the gland or an alteration in the neurotransmitter signaling mechanism in the acinar or ductal cells. The radiation-induced decrease in fluid secretion appears to be related to a change in either the water-handling capacity of the acini or the number of acinar cells in the gland.

Animals↗
PubMed1998

Mutual occlusion of P2X ATP receptors and nicotinic receptors on sympathetic neurons of the guinea-pig.

1. The interaction of ion channels activated by nicotinic receptor agonists with ion channels gated by extracellular ATP (i.e. P2X receptors) was studied on sympathetic neurons acutely dissociated from coeliac ganglia of the guinea-pig. Patch clamp methods were used to measure the inward current generated through these non-selective cationic channels under voltage clamp. 2. At the whole cell level, the specific nicotinic receptor agonists nicotine (5-100 microM) or cytisine (50-75 microM) and the P2X receptor agonists ATP (0.1-7 microM) or alpha,beta-methylene ATP (6 microM) were examined separately and in the presence of the other receptor activator. When a nicotinic and P2X receptor agonist were applied together, mutually occlusive effects were generally observed. This occurred even with concentrations of agonists that in themselves generated little to no inward current. 3. The occlusive effects of nicotinic agonists on ATP-gated currents were blocked by the nicotinic receptor/ion channel blocker hexamethonium (150 microM). The occlusive effects of ATP analogues on inward currents generated by nicotinic agonists were blocked by the P2X receptor antagonist suramin (100 microM). 4. Mutual occlusion of the effects of nicotinic agonists and ATP analogues were also observed when currents through single channels were studied in excised (outside-out) patches. 5. The results suggest that nicotinic receptors and P2X ATP receptors do not act independently in these sympathetic neurons.

Adenosine Triphosphate↗
PubMed1998

Enzyme histochemical and immunohistochemical localization of carbonic anhydrase as a marker of ductal differentiation in the developing rat parotid gland.

BACKGROUND: Carbonic anhydrase has been localized to the acini and ducts of mature rat parotid glands. This enzyme has been associated with ion transport, a prominent function of striated and excretory ducts in salivary glands, suggesting that it might be used as a marker of ductal differentiation. The purpose of this study was histochemically to document developmental changes in carbonic anhydrase in the ducts of the rat parotid gland. METHODS: Parotid glands were excised from rats at representative developmental ages. Enzyme histochemistry was done on frozen sections fixed in acetone, and immunohistochemistry was performed with antibodies to human carbonic anhydrase isoenzymes I, II, and VI on paraffin sections of glands fixed in Helly's fluid. RESULTS: Carbonic anhydrase activity was weak until age 21 days after birth, when it had increased slightly in the acini and intercalated ducts and moderately in striated and excretory ducts. The adult pattern was attained by 28 days, in which reactions were moderate to strong in the striated and excretory ducts and modest in the acini and intercalated ducts. Immunohistochemical reactions were weak until 14 days, then increased rapidly, and by 28 days approached the adult pattern of virtually none in the acini and modest to moderately strong in the striated and excretory ducts. The order of reaction intensity of the antibodies was II > I > VI. CONCLUSIONS: Carbonic anhydrase is a useful marker of the functional differentiation of the striated and excretory ducts of the developing rat parotid gland.

Animals↗
PubMed1998

A polarized salivary cell monolayer useful for studying transepithelial fluid movement in vitro.

There are no reported, convenient in vitro models for studying polarized functions in salivary epithelial cells. Accordingly, we examined three often-used salivary cell lines for their ability to form a polarized monolayer on permeable, collagen-coated polycarbonate filters. Only the SMIE line, derived from rat submandibular gland, had this ability. The SMIE cell monolayer exhibited junctional complexes, with a tight-junction-associated protein, ZO-1, localized to cell-cell contact areas. The Na+/K+-ATPase alpha1-subunit was detected predominantly in the basolateral membranes, while the Na+/H+ exchanger isoform 2 appeared primarily in the apical membranes. Using adenovirus-mediated cDNA transfer, SMIE cells were shown to be capable of routing marker proteins (beta-galactosidase +/- a nuclear targeting signal, alpha1-antitrypsin, aquaporin-1) to appropriate locations. Furthermore, this salivary cell monolayer provided a convenient tool for studying aquaporin-1-mediated, osmotically directed, transepithelial fluid movement in vitro. Thus, SMIE cells appear to be a useful experimental model with which to study some polarized functions in a salivary epithelial cell line.

Adenoviridae↗
PubMed1998

Development and characterization of SV40 immortalized rat parotid acinar cell lines.

Rat parotid salivary gland acinar cells were transfected by CaPO4 precipitation using a plasmid containing a replication-defective simian virus (SV40) genome. Out of 30 clonal cell lines, 2 were shown to have moderate to high levels of cytodifferentiation and salivary gland acinar cell function. Functional studies with the two cell lines indicated that the beta-adrenergic agonist (isoproterenol), vasoactive intestinal peptide prostaglandin E1, and forskolin were effective activators of intracellular cyclic adenosine 3':5'-cyclic monophosphate production. Phenylephrine, carbamylcholine, and UTP were effective in increasing inositol phosphate production and intracellular free calcium levels, whereas substance P was without affect. Utilizing indirect immunofluorescence analysis, both cell lines were shown to express the SV40 large T antigen. Electron microscopic evaluation documented moderate to high levels of cytodifferentiation with the maintenance of tripartite junctional complexes, cellular polarization, and presence of moderate amounts of secretory granules and rough endoplasmic reticulum. The two cell lines had doubling times of 22 and 36 h, respectively.

3T3 Cells↗
PubMed1998

A rat parotid gland cell line, Par-C10, exhibits neurotransmitter-regulated transepithelial anion secretion.

Because of the lack of salivary gland cell lines suitable for Ussing chamber studies, a recently established rat parotid acinar cell line, Par-C10, was grown on permeable supports and evaluated for development of transcellular resistance, polarization, and changes in short-circuit current (Isc) in response to relevant receptor agonists. Par-C10 cultures reached confluence in 3-4 days and developed transcellular resistance values of >/=2,000 Omega . cm2. Morphological examination revealed that Par-C10 cells grew as polarized monolayers exhibiting tripartite junctional complexes and the acinar cell-specific characteristic of secretory canaliculi. Par-C10 Isc was increased in response to muscarinic cholinergic and alpha- and beta-adrenergic agonists on the basolateral aspect of the cultures and to ATP and UTP (through P2Y2 nucleotide receptors) applied apically. Ion replacement and inhibitor studies indicated that anion secretion was the primary factor in agonist-stimulated Isc. RT-PCR, which confirmed the presence of P2Y2 nucleotide receptor mRNA in Par-C10 cells, also revealed the presence of mRNA for the cystic fibrosis transmembrane conductance regulator and ClC-2 Cl- channel proteins. These findings establish Par-C10 cells as the first cell line of salivary gland origin useful in transcellular ion secretion studies in Ussing chambers.

Adenosine Triphosphate↗
PubMed1998

Development and characterization of immortalized rat parotid and submandibular acinar cell lines.

The purpose of this investigation was to develop well-differentiated rat parotid and submandibular acinar cell lines. Acinar cells dissociated from rat parotid and submandibular glands were grown on Mitomycin C-treated 3T3 fibroblasts or Matrigel in primary culture and transfected by CaPO4 precipitation using a plasmid containing a replication-defective simian virus (SV40) genome. Cytokeratin analysis via indirect immunofluorescence and receptor mediated changes in intracellular calcium and cyclic AMP were assessed and used for the identification and selection of immortalized epithelial cells. Of the more than 60 clonal cell lines, four retained moderate to high levels of acinar differentiation through >60 passages. Ultrastructurally, there were tripartate junctional complexes and moderate amounts of rough endoplasmic reticulum and secretory granules. Functional studies indicated that beta-adrenoceptors, vasoactive intestinal peptide, and prostaglandin E1 were effective activators of intracellular cyclic AMP production in all cell lines. Alpha-adrenoceptors, muscarinic cholinoceptors, and P2U-purinoceptor agonists were effective in increasing intracellular inositol phosphate production and free calcium levels whereas substance P was ineffective. These data document the utility of the SV40 plasmid in immortalizing rat parotid and submandibular acinar cells that retain most of the features of acinar differentiation.

Animals↗
PubMed1998

In vivo use of adenoviral vectors: effects on salivary gland structure.

Recently there has been considerable progress in the development of in vivo gene transfer technology. By this means, new genetic information may be introduced directly to cells, while the cells remain in their natural milieu. The ability to express exogenous proteins makes it possible to explore the functions of native or altered proteins and thereby develop new insights into cell function and dysfunction. We have demonstrated that the major salivary glands are efficiently infected by recombinant adenovirus vectors. These vectors are capable of expressing transgenes in both acinar and ductal cell types. Recently, we have developed vectors that contain cell-specific promoters so that proteins may be expressed in selected subpopulations of salivary cells. Early generations of adenoviral vectors elicited potent immune responses in vivo. However, modified vectors and adjunctive measures have improved the safety of gene transfer to salivary glands. Future studies will aim to increase the duration of adenovirus-based gene expression and to produce vector systems that are not toxic to the host.

Adenoviridae↗
PubMed1997

Opposing effects of phorbol esters on transmitter release and calcium currents at frog motor nerve endings.

1. Phorbol esters activate protein kinase C (PKC) and also increase the secretion of neurotransmitter substances by an unknown mechanism. To evaluate whether the stimulatory effects of such agents on acetylcholine (ACh) secretion occur as a consequence of stimulation of Ca2+ entry, we made electrophysiological measurements of ACh secretion (i.e. endplate potentials, EPPs) and the component of the prejunctional perineural voltage change associated with nerve terminal calcium currents (perineural calcium current) at frog neuromuscular junctions. 2. In the first series of experiments, modest concentrations of K+ channel blockers were employed so that simultaneous measurements of EPP amplitudes and perineural calcium currents could be made. In these experiments, 12-O-tetradecanoylphorbol 13-acetate (TPA; 162 nM) and phorbol 12,13-dibutyrate (PDBu; 100-200 nM) each increased ACh release but simultaneously decreased the calcium component of the prejunctional perineural current TPA and PDBu also inhibited perineural calcium currents in the presence of higher concentrations of K+ channel blockers. 3. Blockade of Ca2+ channels by Cd2+ prevented the action of PKC stimulators on perineural waveforms. 4. The inactive compound 4-alpha-phorbol 12-myristate 13-acetate (150 nM) did not affect EPP amplitudes or perineural currents. 5. The extracellular [Ca2+]-ACh release relationship was increased in maximum by PDBu without any change in the potency of Ca2+ to support evoked ACh release. 6. The results demonstrate that phorbol esters increase neurotransmitter secretion whilst simultaneously decreasing the nerve ending calcium currents that promote evoked release. The results, which suggest that the optimal control point for secretion might not be the calcium channel but rather a component of the secretory apparatus, are discussed in conjunction with the possible target sites for phorbol esters in the nerve ending.

Acetylcholine↗
PubMed1997

Cholesterogenesis, lipogenesis, cholesterol degradation to bile acids, and histopathology of the liver in LA/N-cp obese rats.

Various lipid parameters were determined in lean control and LA/NIH-corpulent (LA/N-cp) rats, a normotensive strain showing metabolic characteristics associated with human Type IV hyperlipidemia. Hepatic and plasma total cholesterol, high density lipoproteins (HDL) cholesterol and triglycerides were significantly higher in the obese group than in the control group. Depending upon whether the data were expressed as per gram tissue or per organ, the rates of de novo fatty acid synthesis in the liver and adipose tissue were higher by 61% to 127% (P < .05) and 79% to 355% (P < .05), respectively, in the obese group compared with the lean control group. Similarly, hepatic rate of cholesterol synthesis was higher by 46% to 107% (P < .05) in the obese animals compared with the lean ones. In vivo hepatic rate of HDL2 cholesterol degradation to bile acids was lower in the obese group by 48% to 63% (P < .05). This was confirmed in the perfused liver in spite of the fact that cholesterol uptake from HDL2 was 3- to 4-fold higher in the obese group. These changes in lipid parameters of the obese animals were neither caused by hyperphagia because they were pair-fed with the control group nor caused by increased rate of food consumption because they were meal-fed. At the same time, all these lipid parameters were 17% to 20% higher in ad libitum-fed obese than in pair-fed obese group. Histopathological evaluation of the livers in the obese and control groups also showed prominent lipid droplets in the cytoplasm of the obese liver but not in the lean control liver. Thus, the possible causes of obesity in the LA/N-cp obese rats are higher synthetic rates of lipids coupled with lower rate of degradation of cholesterol to bile acids.

Animals↗
PubMed1997

Characterization of a linear DNA plasmid from the filamentous fungal plant pathogen Glomerella musae [Anamorph: Colltotrichum musae (Berk. & Curt.) Arx.].

A 7.4-kilobase (kb) DNA plasmid was isolated from Glomerella musae isolate 927 and designated pGML1. Exonuclease treatments indicated that pGML1 was a linear plasmid with blocked 5' termini. Cell-fractionation experiments combined with sequence-specific PCR amplification revealed that pGML1 resided in mitochondria. The pGML1 plasmid hybridized to cesium chloride-fractionated nuclear DNA but not to A + T-rich mitochondrial DNA. An internal 7.0-kb section of pGML1 was cloned and did not hybridize with either nuclear or mitochondrial DNA from G. musae. Sequence analysis revealed identical terminal inverted repeats (TIR) of 520 bp at the ends of the cloned 7.0-kb section of pGML1. The occurrence of pGML1 did not correspond with the pathogenicity of G. musae on banana fruit. Four additional isolates of G. musae possessed extrachromosomal DNA fragments similar in size and sequence to pGML1.

Ascomycota↗
PubMed1997

Development and characterization of SV40 immortalized rat submandibular acinar cell lines.

Rat submandibular salivary gland acinar cells were transfected by CaPO4 precipitation using a plasmid containing a replication-defective simian virus (SV40) genome. Out of 27 clonal cell lines, two were shown to have moderate to high levels of cytodifferentiation and salivary gland acinar cell function. Functional studies with the two cell lines indicated that the beta-adrenergic agonist, isoproterenol, vasoactive intestinal peptide, and prostaglandin E1 were effective activators of intracellular cyclic AMP production. Epinephrine, norepinephrine, phenylephrine, acetylcholine, and P2U-purinoceptor agonists were effective in increasing inositol phosphate production and intracellular free calcium levels, whereas substance P was without effect. Utilizing indirect immunofluorescence analysis, both cell lines were shown to express glutamine/glutamic acid-rich proteins, a submandibular acinar cell specific secretory protein family. Electron microscopic evaluation documented the maintenance of tripartite junctional complexes, cellular polarization, and the presence of moderate amounts of secretory granules and rough endoplasmic reticulum. The two cell lines had doubling times of 25 h.

Animals↗
PubMed1997

Effect of substance P and receptor antagonists on secretion of lingual lipase and amylase from rat von Ebner's gland.

Substance P (SP, 1 microM) when incubated with minced von Ebner's glands for 15, 30, and 60 min, stimulated secretion of lingual lipase (12.14% +/- 0.90) and amylase (8.30% +/- 0.42). Only 10 microM of the SP receptor antagonist CP-96,345 significantly inhibited SP-evoked secretion. D-Pro2-D-Phe7-D-Trp9-SP (Ia), D-Pro2-D-Trp7,9-SP (Ib), D-Arg1-D-Trp7,9-D-Leu11-SP (Ic), or 1 microM CP-96,345 were not effective, suggesting that the SP receptor of von Ebner's gland might be an isoform. Propranolol and timolol, beta 1/beta 2-adrenergic receptor antagonists were not effective and the cholinergic receptor antagonist, atropine, was effective in only slightly reducing amylase secretion but not lingual lipase. Differential secretion of the two enzymes was observed for basal and stimulated secretion. Thus, exocytosis may not be the only pathway involved in SP-evoked protein secretion.

Amylases↗