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Biomedical subjects

M E Rose

Publications and source records attributed to M E Rose.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of selective oxidation of 1-34 bovine parathyroid hormone on its renal actions in the rabbit.

Oxidation of both of the methionine residues (positions 8 and 18) in parathyroid hormone (PTH) eliminates many of its biological effects. The present studies were performed to examine the actions of 1,34 bovine PTH and 1-34 bovine PTH oxidized selectively at Met 8, at Met 18, and at both sites on renal electrolyte handling and on adenylate cyclase (AC) stimulation. In clearance studies in anesthetized rabbits, PTH caused a phosphaturia and an anticalciuria. PTH also stimulated renal proximal tubular AC in vitro and increased renal cortical cAMP content in vivo. PTH oxidized at Met 18 was anticalciuric, but not phosphaturic, stimulated renal AC and increased cortical cAMP content. PTH oxidized at Met 8 also produced an anticalciuria without a phosphaturia, but only weakly stimulated AC and did not alter cortical cAMP content. PTH oxidized at both Met 8 and Met 18 was phosphaturic but not anticalciuric, was a weak agonist for AC and decreased cortical cAMP content. In the isolated perfused rabbit proximal straight tubule, PTH inhibited fluid and phosphate transport, whereas the doubly oxidized peptide was inactive. The data are consistent with the possibility that the effects of PTH on renal tubular phosphorus transport are mediated by more than one mechanism and are, in part, independent of the cAMP messenger system.

Adenylyl Cyclases↗
PubMed1988

Lymphocytes of the intestinal mucosa of chickens.

Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.

Animals↗
PubMed1988

Isolation and analysis of ketoconazole resistant mutants of Saccharomyces cerevisiae.

Nine mutants of Saccharomyces cerevisiae which are resistant to ketoconazole, have been isolated and characterized. In each case the mutation is nuclear in origin and allelic to a previously described mutation, erg3, which gives rise to a block in the delta 5-6 desaturation step of ergosterol biosynthesis. The significance of this second site mutation to the point of inhibitory action of ketoconazole, that is the P-450-mediated C-14 demethylation of lanosterol, is discussed.

Cytochrome P-450 Enzyme System↗
PubMed1988

Immunity to coccidiosis: adoptive transfer in NIH mice challenged with Eimeria vermiformis.

The development of a reliable model for the adoptive transfer of immunity to coccidiosis (infection with Eimeria vermiformis in NIH mice) is described. More than 10(8) of a mixture of spleen and mesenteric lymph node (MLN) cells, given either intravenously or intraperitoneally, were required to transfer a significant degree of protection. Dividing cells, present in the donors at 10 or 14 days after priming, but not at 5 or 19 days, were shown to be the effectors. When examined separately, MLN cells were found to be superior to spleen cells, and the injection of as few as 5 x 10(7) was capable of substantially reducing the oocyst output from a challenge inoculum. The recipients of cells from primed mice had earlier, and sometimes higher, titres of specific antibodies in the serum but, overall, there was no correlation between these titres and protection. Further characterization of the cells responsible for adoptively transferring immunity to this infection should now be possible.

Animals↗
PubMed1988

Eimeria tenella: immunological diversity between asexual generations.

In the development of a normal strain, WIS, of Eimeria tenella there are three generations of schizogony whereas in an attenuated line, WIS-F-96, derived from WIS, the second and third are absent. Chickens immunized by infection with WIS-F-96, however, were highly resistant to oral challenge with sporulated oocysts of WIS, and histological studies indicated that the immune response was directed against the sporozoites from that challenge inoculum. When challenge of the WIS-F-96-primed chickens consisted of second generation merozoites of WIS (inoculated intracaecally), immunity was less pronounced and the histological data indicated that the merozoites proceeded to develop normally in these birds. These indications of immunological diversity between the merozoites of the first and second generations of schizogony of E. tenella WIS correlated with the results of preliminary studies of the antigenic composition of these developmental stages.

Animals↗
PubMed1988

Resistance to infection with Eimeria vermiformis in mouse radiation chimeras is determined by donor bone-marrow cells.

The course of infection with Eimeria vermiformis was determined in BALB/b, BALB/c, and C57BL/10ScSn (B10) mice and in radiation chimeras prepared from the H-2-compatible BALB/b and B10 mice. The BALB strains, irrespective of H-2 haplotype, were resistant, the B10 mice were susceptible, and in the chimeras infection was characterized by the genotype of the donated bone-marrow cells and not by the phenotype of the recipient. Thus, the genetic control of relative resistance or susceptibility to infection with this parasite is expressed through bone-marrow-derived cells.

Animals↗
PubMed1988

Mediation of immunity to Eimeria vermiformis in mice by L3T4+ T cells.

Immunity to infection with Eimeria vermiformis was transferred in NIH mice by both the nylon wool-adherent (B-cell-enriched) and nonadherent (T-cell-enriched) fractions of lymphocytes (spleen and mesenteric lymph node) taken from infected donors. Transfer was more variable with the adherent fraction, and when contaminating T cells were removed by treatment with anti-Thy1 monoclonal antibody (MAb) and complement, this fraction lost all protective activity. The protective effect of T-cell-enriched populations of mesenteric lymphocytes was abrogated by treatment with anti-L3T4 MAb and complement in vitro before transfer or by opsonization with this MAb in vitro before intravenous inoculation into recipients. Similar treatments of cells with anti-Lyt2 MAb did not have this effect, confirming that Thy1+ L3T4+ cells mediate the adoptive transfer of immunity to E. vermiformis. Thy1+ L3T4+ cells were also shown to limit the replication of E. vermiformis in primary infections: mice depleted of this subset (by thymectomy followed by intravenous injection of anti-L3T4 MAb) passed greater numbers of oocysts over a longer period of time than did mice similarly depleted of Lyt2+ cells.

Animals↗
PubMed1988

Inhibitory effects of volume expansion performed in vivo on transport in the isolated rabbit proximal tubule perfused in vitro.

To examine the renal tubular sites and mechanisms involved in the effects of hypooncotic volume expansion (VE) on renal electrolyte excretion, we performed clearance and isolated tubular perfusion studies using intact and thyroparathyroidectomized (TPTX) rabbits. We also examined the effect of VE on luminal brush border transport. In the microperfusion studies, proximal convoluted (PCT) and straight (PST) tubules were taken from rabbits without prior VE or after 30 min of 6% (body wt) VE. Acute VE increased the percentage excretion of Na, Ca, and P in TPTX animals and the percentage and absolute excretions of these ions in intact rabbits. In PST from VE animals, fluid flux (Jv) was depressed compared with Jv in PST from nonVE rabbits: Jv = 0.18 +/- 0.03, (VE) vs. 0.31 +/- 0.03 nl/mm.min, (nonVE) P less than 0.02. Phosphate transport (Jp) in the PST from VE animals was also depressed: JP = 1.58 +/- 0.10 (VE) vs. 2.62 +/- 0.47 pmol/mm.min, (nonVE) P less than 0.05. Similar results were obtained with TPTX animals. In the PCT from VE animals, Jv was decreased (0.49 +/- 0.10 (VE) vs. 0.97 +/- 0.14 nl/mm.min, (nonVE) P less than 0.02), but JP was not affected significantly. Transport inhibition was stable over approximately 90 min of perfusion. In the brush border vesicle studies, sodium-dependent phosphate transport was inhibited compared with that in control animals, at the 9-, 30-, and 60-s time points. These findings indicate that the inhibition of renal ionic transport by VE occurs in both PCT and PST and is, in part, the result of a direct effect of VE on tubular transport mechanisms.

Animals↗
PubMed1987

Eimeria tenella: effects of immunity on sporozoites within the lumen of the small intestine.

The effect of immunity on the numbers of sporozoites of Eimeria tenella recoverable from the lumen of the small intestine 1 hr after an oral challenge inoculum of oocysts was examined. The experiments were carried out in chickens which had been given an immunizing inoculum of oocysts 9 or 18 days earlier, and the results were compared with those obtained in a control, unprimed, but similarly challenged, group. Similar numbers of "challenge" sporozoites were found in the intestinal washes of control and 18 day primed chickens but there were fewer in the 9 day primed groups. The titers of antisporozoite IgA antibodies (measured by indirect fluorescence) were higher in the gall bladder bile of the 9 day primed groups but resistance to reinfection (measured by the output of oocysts in the feces after challenge with oocysts orally or with sporozoites intracecally) was greater in the 18 day primed group. Although fewer in number, the challenge sporozoites recovered from the intestinal washes of 9 day primed chickens appeared to be morphologically normal when examined by light microscopy. Also, they were as infective as sporozoites recovered from unprimed control, or 18 day primed, groups when injected intracecally into naive chickens. The findings indicate that, whereas reduction of the number of sporozoites of E. tenella in the lumen of the small intestine (presumably caused by the action of secreted antibodies) can be a means of reducing the effective challenge inoculum, this mechanism does not play a major role in the expression of immunity.

Animals↗
PubMed1987

Eimeria tenella sporozoites: the method of excystation affects the surface membrane proteins.

Eimerian sporozoites can be recovered from intestinal washings after oral administration of oocysts to chickens but suspensions of sporozoites are usually prepared in the laboratory by incubation of sporocysts or fractured oocysts in vitro, at body temperatures, with relatively high concentrations of trypsin and bile salts. Since these agents affect membrane structure, the surface membrane of proteins of Eimeria tenella sporozoites excysted in vivo and in vitro have been compared. Surface radio-iodination followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that more 125I was incorporated into polypeptides on sporozoites excysted in vivo than on sporozoites excysted in vitro. The 125I-polypeptide profile of sporozoites excysted in vivo was more resistant to subsequent incubation with pure trypsin than that of sporozoites excysted in vitro, but incubation with bile salts resulted in the loss of some iodinated polypeptides from both preparations of iodinated sporozoites. Reaction with combinations of crude trypsin and bile salts led to the lysis of sporozoites. The method of excystation had no effect on the reaction of convalescent chicken serum with Western blots of sporozoites but the results of immunofluorescent staining carried out with mouse monoclonal antibodies indicated that the structure of the cell surface was altered and some antigenic determinants were lost from sporozoites excysted in vitro. In contrast, neither the infectivity of sporozoites determined in vivo, nor their invasion of cultured cells was changed by the method of excystation.

Animals↗
PubMed1987

The effects of atrial natriuretic peptide on whole-kidney and proximal straight tubular function in the rabbit.

The mechanisms by which atrial natriuretic peptide (ANP) produces a diuresis and natriuresis remain unclear. It has been suggested that the major if not sole mediator of ANP's renal effects is a hemodynamically induced increase in glomerular filtration rate (GFR). Data from clearance studies in anesthetized rabbits demonstrate that ANP administration can produce a significant increase in absolute and percentage sodium excretion (42.0 +/- 5.9----64.6 +/- 10.2 mu eq/min, P less than 0.01, and 1.97 +/- 0.28----3.12 +/- 0.35%, P less than 0.001, respectively) without increasing GFR (16.8 +/- 2.1----16.1 +/- 2.5 cc/min, P greater than 0.30). The natriuresis occurred despite a fall in renal plasma flow (RPF) (56.7 +/- 7.0----44.5 +/- 9.4 cc/min, P less than 0.01), a rise in filtration fraction (0.33 +/- 0.01----0.46 +/- 0.05, P less than 0.01), and an unchanged filtered load of sodium (2.28 +/- 0.27----2.16 +/- 0.32 mu eq/min, P greater than 0.10). Isolated tubular microperfusion studies demonstrated that ANP, present as a 10(-9) M concentration in the solution bathing perfused proximal straight tubules (PST), did not affect fluid flux (Jv) (0.38 +/- 0.07----0.41 +/- 0.07 nl/mm/min, P greater than 0.30) or phosphate reabsorption (Jp) (1.50 +/- 0.5----1.38 +/- 0.36 pmole/mm/min, P greater than 0.50). When ANP was infused into rabbits prior to harvesting the PSTs for isolated tubular microperfusion and the results were compared to tubules taken from control animals, there was again no effect on Jv (0.37 +/- 0.05 vs 0.42 +/- 0.05 nl/mm/min, P greater than 0.50) or Jp (2.41 +/- 0.27 vs 2.42 +/- 0.44 pmole/mm/min, P greater than 0.90). These findings suggest that ANP can inhibit sodium transport without increasing whole-kidney GFR or RPF, but does not directly inhibit transport in the proximal straight tubule.

Animals↗
PubMed1987

Eimeria spp. of domestic fowl: the migration of sporozoites intra- and extra-enterically.

Chickens were dosed orally with sporulated oocysts of Eimeria acervulina, E. brunetti, E. maxima, or E. praecox and the subsequent presence, in various tissues, of parasites capable of inducing patent infections was detected by transferring the tissues to coccidia-free recipients. Similar results were obtained with each of the 4 species studied, irrespective of whether initial development occurs in the superficial (E. praecox, E. brunetti) or crypt (E. acervulina, E. maxima) epithelium. Infection was transferable by gut scrapings and liver homogenates at all time intervals (3, 6, 12, 18, 24, and 36 hr postinoculation) studied. Infection was also transferable with blood and with splenic homogenates but not consistently. Transfers made within a short time of the inoculation of donors were more successful in producing patent infections in the recipients. In all transfers the prepatent period was normal for the species. These findings suggest that sporozoites enter the mucosa very shortly after inoculation, and some of them pass to the liver and spleen and then leave these tissues at a somewhat slower rate, possibly to reenter the mucosa. Sporozoites in the lamina propria of the gut were found within host mononuclear cells in all 4 species studied. Most of the cells harbouring E. maxima and some of those with E. praecox were identified as intraepithelial lymphocytes while all others could only be identified as agranular mononuclear cells that were not characteristically macrophages.

Animals↗
PubMed1987

Eimeria tenella and E. necatrix: a third generation of schizogony is an obligatory part of the developmental cycle.

The latter part of endogenous development of Eimeria tenella and E. necatrix was examined in sections of cecal tissue taken from chickens infected either by giving oocysts orally or by injecting merozoites into the cecum. The findings, with 3 strains of E. tenella and 1 of E. necatrix, indicate that the majority, if not all, of the parasite populations undergo a third generation of schizogony and then embark upon gametogony.

Animals↗
PubMed1986

Biochemical characterization of chicken secretory component.

Human dimeric IgA was injected i.v. into chickens whose bile was then collected. The human IgA which had been transported across the hepatocytes of the chicken was subsequently purified from the bile and shown to be associated with a protein of 80 kDa and pI 4.6, which reacted with rabbit antisera to chicken bile proteins but not with an antiserum to human alpha chain. The chicken bile protein thus has functional and biochemical properties similar to those of mammalian secretory component.

Animals↗
PubMed1986

Eimeria tenella: immunogenicity of the first generation of schizogony.

The life-cycle of a precocious and attenuated line (WisF96) of Eimeria tenella, derived from the Wisconsin (Wis) strain, contained only the first of the three generations of schizogony undergone by the parent strain. The reproductive capacity of WisF96 was less than that of the parent strain by a factor of about 2000, but inoculation of chickens on two occasions with a large number of its oocysts induced resistance against challenge with oocysts, or with second-generation merozoites of Wis. The immunizing abilities of the attenuated line and its parent were compared by priming groups of chickens with numbers of oocysts of WisF96 or Wis, designed to produce infections of equal magnitude in terms of oocysts production (standard inocula), and then challenging with oocysts of Wis. The results suggested that an equivalent parasite mass of WisF96 was more immunogenic than Wis. This was confirmed by the finding that, even when the priming dose of Wis was increased 10-fold, the standard inoculum of WisF96 still produced the greater protective effect. These results indicate that the first generation of schizogony of E. tenella is highly immunogenic.

Animals↗
PubMed1986

Immune responses to eimeria: quantification of antibody isotypes to Eimeria tenella in chicken serum and bile by means of the ELISA.

The enzyme-linked immunosorbent assay (ELISA) has been used to study the serum IgM and IgG response and the bile IgA and IgM response of chickens to a primary, secondary and tertiary inoculation of Eimeria tenella. In the serum there was a rapid and transient IgM response to the primary infection; second and third inoculations of oocysts had comparatively little effect on the concentrations of this antibody isotype. This differed from the specific IgG response which was later and of similar magnitude after each inoculum. In the bile, specific IgA reached its highest concentrations 9-10 days after the primary inoculation and then declined rapidly. The second and third inoculations each induced low concentrations of this isotype. The specific biliary IgM response to the primary inoculation was similar in profile to that of the IgA, but IgM was detected only on day 14-15 after the second and not at all after the third inoculation. The findings are discussed and are compared with the results obtained using other host species, principally the rat, and with other gut organisms. The relevance of the antibody response in resistance to eimerian infections is also discussed.

Animals↗
PubMed1986

Eimerian life cycles: the patency of eimeria vermiformis, but not Eimeria pragensis, is subject to host (Mus musculus) influence.

The ability of Eimeria vermiformis and Eimeria pragensis to produce oocysts in primary infections is influenced by host factors. Oocyst production and the duration of patency were determined for each species in: NIH mice, normal or immunosuppressed (by X-irradiation or injection of cortisone acetate), and strains of mice: nu/+, nu/nu; BALB/c, C57BL/6 known (E. vermiformis), or suspected (E. pragensis), to be of contrasting susceptibility to infection. The effect of induced or genetic susceptibility on the reproduction of E. vermiformis resulted in increases in both oocyst production and the duration of patency. Eimeria pragensis was less affected, with smaller increases in the numbers of oocysts produced and no significant prolongation of patency. The implications of these findings with respect to eimerian life cycles are discussed.

Animals↗