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Biomedical subjects

B J Cook

Publications and source records attributed to B J Cook.

At least 19 recordsLinked to original sources
PubMed2002

Evaluation of health status of calves and the impact on feedlot performance: assessment of a retained ownership program for postweaning calves.

The objective of this study was to evaluate animal health status at entry to a feedlot against feedlot performance and carcass value. There were 24 herds represented by 417 calves in a retained ownership program. The health status at entry was represented by the levels of serum antibody to infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea viruses 1 and 2 (BVDV1a, BVDV2), parainfluenza 3 virus (PI3V), bovine respiratory syncytial virus (BRSV), Mannheimia haemolytica, and Pasteurella multocida, as well as by the presence of virus in nasal swabs and blood leukocytes and the presence of bacteria in nasal swabs. The presence or absence of viruses or bacteria at entry did not predict subsequent illness. However, there were predictors of illness severity (number of treatments) and performance parameters of feedlot performance. Herds with a low morbidity rate had higher levels of BVDV1a antibodies than herds with a high morbidity rate. On both an individual-animal and a herd-average basis, calves with low levels of antibody to BVDV1a and BVDV2 had increased total treatment costs. Also, for individual animals and the herd as a whole, low levels of antibody to P. multocida, BVDV1a, and BVDV2 were related to decreased net value to owner (carcass value minus total feedlot cost). Calves treated twice or more had lower levels of antibody to BVDV1a than those treated once or not at all. Differences in herd morbidity rate and treatment costs were more related to appropriate timing of vaccine (last dose at or near delivery of calf) or lack of a 2nd dose of killed vaccine. This was best illustrated by the levels of antibody to BVDV1a. The results of this study were used to formulate recommendations for the subsequent year.

Animal Husbandry↗
PubMed2000

Fusion of childhood inguinal hernia induced by HGF and CGRP via an epithelial transition.

BACKGROUND/PURPOSE: Recent evidence has suggested that calcitonin gene-related peptide (CGRP), which is released from the genitofemoral nerve, may trigger fusion of the patent processus vaginalis in children with inguinal hernia. The purpose of this study was to determine whether CGRP triggers the release of mesenchymal factors leading to subsequent fusion of the processus vaginalis. METHODS: The response of cultured epithelial cells derived from the patent processus vaginalis was analysed by a novel in vitro culture system. Epithelial cells lining fresh hernial sacs (removed at inguinal herniotomy) were detached enzymatically and cultured for 72 hours on Micropore filters, in the presence of either 100 ng/mL hepatocyte growth factor (HGF), 7.4 x 10(-6) mol/L CGRP (amino acids 1 to 37), 7.4 x 10(-6) mol/L CGRP (8 to 37) antagonist, 10% fetal calf serum (FCS), or serum-free medium (SFM) alone. Transformation from an epithelial cell morphology to motile mesenchymal fibroblast-like cells was assessed by an average migration score (AMS), ranging from 0 with no sign of migration, to 3 with greater than 75% of cells migrating. Confocal microscopy was used to record changes in expression of epithelial (cytokeratin) and mesenchymal (vimentin) markers, as well as actin. Beta-catenin also was examined because it is part of the molecular complex that links cadherins to actin resulting in cell-cell adhesion. RESULTS: Epithelial and mesenchymal markers underwent either down-regulation or up-regulation as epithelial cell sheets broke apart and individual cells commenced migration. The AMS after 72 hours of culture was 0.22 with SFM (control); with FCS the score was 1.4 (P < .01). The AMS score with CGRP (1 to 37) was 0.55 (P = .165) and with its analogue, CGRP (8 to 37), which is a competitive inhibitor, 0.67 (P = .309). Neither was significant. HGF caused a significant increase in the AMS to 1.56 (P = .01). CONCLUSION: Both HGF and FCS (which contains various undefined peptides and growth factors) produced transformation of hernial sac epithelial cells, whereas CGRP and its inactive analogue did not. CGRP receptors are localised to mesenchymal fibroblasts within the processus vaginalis connective tissue, suggesting that CGRP could act indirectly via HGF, which, in turn, promotes fusion of the processus vaginalis. In the future, a nonsurgical treatment of inguinal herniae in children might be possible by the local administration of agents which promote fusion.

Actins↗
PubMed1999

Fungal polygalacturonases exhibit different substrate degradation patterns and differ in their susceptibilities to polygalacturonase-inhibiting proteins.

Polygalacturonic acid (PGA) was hydrolyzed by polygalacturonases (PGs) purified from six fungi. The oligogalacturonide products were analyzed by HPAEC-PAD (high performance anion exchange chromatography-pulsed amperimetric detection) to assess their relative amounts and degrees of polymerization. The abilities of the fungal PGs to reduce the viscosity of a solution of PGA were also determined. The potential abilities of four polygalacturonase-inhibiting proteins (PGIPs) from three plant species to inhibit or to modify the hydrolytic activity of the fungal PGs were determined by colorimetric and HPAEC-PAD analyses, respectively. Normalized activities of the different PGs acting upon the same substrate resulted in one of two distinct oligogalacturonide profiles. Viscometric analysis of the effect of PGs on the same substrate also supports two distinct patterns of cleavage. A wide range of susceptibility of the various PGs to inhibition by PGIPs was observed. The four PGs that were inhibited by all PGIPs tested exhibited an endo/exo mode of substrate cleavage, while the three PGs that were resistant to inhibition by one or more of the PGIPs proceed by a classic endo pattern of cleavage.

Amino Acid Sequence↗
PubMed1996

CfMNPV blocks AcMNPV-induced apoptosis in a continuous midgut cell line.

Morphological and molecular changes produced by Autographa californica nuclear polyhedrosis virus (AcMNPV) infection in a permissive cell line, IPLB-SF-21AE (SF-21), of Spodoptera frugiperda and a nonpermissive cell line, FPMI-CF-203 (CF-203), of Choristoneura fumiferana are described. CF-203 cells inoculated with AcMNPV showed a DNA ladder and morphological changes such as plasma membrane granulation, blebbing, and nuclear fragmentation, which are characteristic of apoptosis. Typical virus replication and occlusion body (OB) production were seen in SF-21 cells inoculated with AcMNPV and no apoptosis-like symptoms were observed. mRNA for the apoptosis suppressor gene p35 was detected 9 hr later in AcMNPV-inoculated CF-203 cells than in SF-21 cells. Only a trace amount of mRNA for the AcMNPV-inhibitor of apoptosis homologue (Ac-iap) gene and no mRNAs for the late genes, AcMNPV-polyhedrin (Ac-polh) and AcMNPV-p10 (Ac-p10), were detected in AcMNPV-inoculated CF-203 cells. Inoculation of CF-203 cells with CfMNPV at least 12 hr prior to inoculation with AcMNPV prevented apoptosis-like cell death, and mRNAs for Ac-iap, Ac-polh, and Ac-p10 genes were expressed resulting in successful virus replication and OB production.

Animals↗
PubMed1996

Cloning and developmental expression of Choristoneura hormone receptor 3, an ecdysone-inducible gene and a member of the steroid hormone receptor superfamily.

Degenerate oligonucleotides and cDNA converted from Choristoneura fumiferana embryonic RNA were used in a polymerase chain reaction (PCR) procedure to isolate a 683 bp cDNA fragment. Comparison of the deduced amino acid sequence of this cDNA fragment showed that it was a region of an MHR3-like gene from C. fumeferana; we therefore named it Choristoneura hormone receptor 3 (CHR3). This CHR3 cDNA fragment was used as a probe to screen a C. fumiferana embryonic cDNA library. Twenty clones were isolated and two overlapping clones were sequenced. The longest open reading frame of CHR3 cDNA codes for 546 amino acids. The deduced amino acid sequence of this open reading frame contained all five regions typical of a steroid hormone nuclear receptor. The C domain showed the highest identity to Manduca hormone receptor 3 (MHR3), Drosophila hormone receptor 3 (DHR3) and Galleria hormone receptor 3 (GHR3). The A/B, D and E domains also showed significant amino acid similarity with MHR3, DHR3 and GHR3. The 683 bp CHR3 cDNA probe detected two mRNAs of 3.8 and 4.5 kb present during the ecdysteroid peaks for embryonic, larval, pupal and adult molts but were not detected during the intermolt periods. In sixth instar larvae, the 3.8 and 4.5 kb mRNA were detected in the epidermis, fat body and midgut tissues and the maximum expression was observed during the prepupal peak of ecdysteroids in the hemolymph. CHR3 mRNA was induced in 20-hydroxyecdysone treated CF-203 cells as well as in the midgut, fat body and epidermis of larvae that were fed the non-steroidal molting hormone agonist, RH-5992. In vitro transcription and translation of the CHR3 cDNA yielded a 61 kDa protein that bound to the retinoid related orphan receptor response element.

Amino Acid Sequence↗
PubMed1996

Structural characterization of peripheral nerve cells and nerve-muscle junctions of the oviduct of stable fly (Diptera:Muscidae).

Fine structure of both peripheral nerve cells and neuromuscular junctions associated with the oviduct of stable fly. Stomoxys calcitrans (L.), was described. Twelve or more multipolar peripheral neurons were found along major branch nerves that enter the ovipositor. Several were suspended in the haemacoel and others were in close proximity to the surface of the oviduct. Some peripheral neurons contained an abundance of neurosecretory granules that ranged in size from 32 to 180 nm in diameter. No glial elements enveloped the perikarya of such cells. Neurosecretory axons were usually found in the boundary region of large nerves just beneath the stroma. Peripheral nerve cells in close apposition to oviduct muscles were generally non-neurosecretory and were ensheathed in a glial perineurium. Peripheral neurons were surrounded occasionally by an extensive network of extracellular spaces in the glial perineurium. Other smaller neurons were found within large nerve trunks. Nerve-muscle junctions contained large clusters of synaptic vesicles and occasionally included small groups of neuro-secretory granules. Many nerve terminals on the surface of the oviduct contained a complex postsynaptic folding of sarcolemma. Active transmission sites were indicated by increased densities along the neurolemma. Some neurohemal release sites were also evident.

Animals↗
PubMed1995

Analysis of ecdysteroid action in Malacosoma disstria cells: cloning selected regions of E75- and MHR3-like genes.

IPRI-MD-66 (MD-66) cells respond to 20-hydroxyecdysone (20E, 4 x 10(-6) M) in the medium by producing cytoplasmic extensions, clumping and attaching themselves to the substrate. These morphological changes are at a maximum by 6 days post treatment. Degenerate oligonucleotides, designed on the basis of conserved amino acid sequences in the DNA and ligand binding regions of the members of the steroid hormone receptor superfamily, were used in RNA-PCR to isolate two cDNA fragments, Malacosoma disstria hormone receptor 2 (MdHR2) and Malacosoma disstria hormone receptor 3 (MdHR3) from the MD-66 cells. Comparison of deduced amino acid sequences of these cDNA fragments with the members of the steroid hormone receptor superfamily showed that MdHR2 is most closely related to E75 proteins of Manduca sexta, Galleria mellonella and Drosophila melanogaster. The MdHR3 is most closely related to Manduca hormone receptor 3 (MHR3), Galleria hormone receptor 3 (GHR3) and Drosophila hormone receptor 3 (DHR3) proteins. At a concentration of 4 x 10(-6) M, 20E induces the expression of MdHR2 and MdHR3 beginning at 3 h, reaching maximum levels in 12 h and declining in 24 h. MdHR2 binds to a 2.5 kb mRNA, whereas MdHR3 binds to a 4.5 kb mRNA. Based on sequence similarity, RNA size and ecdysone inducibility, we conclude that these cDNA fragments, cloned from MD-66 cells, are regions of E75- (MdHR2) and MHR3- (MdHR3) like genes.

Amino Acid Sequence↗
PubMed1995

Structural characterization of muscles and epithelial sheaths of the oviduct of Stomoxys calcitrans (Diptera: Muscidae).

Fine structure of both muscle and epithelial cells in the oviduct of Stomoxys calcitrans (L.) was characterized. Each tubular section of the oviduct consisted of an inner epithelial sheath enveloped by an outer network of muscle fibers that showed noticeable variation in cross-sectional thickness. Some regions consisted of a single cellular layer, whereas others were composed of two or more layers of cells. Moreover, a wide variation in muscle fiber orientation was observed, with some cells appearing circular and others appearing nearly longitudinal. The myofibrils of oviduct muscles were separated into sarcomeres of irregular alignment. The classical A (1 microns in length) and I bands of myofilaments were evident, but the Z disk consisted of discontinuous rows of dense bodies. In partially contracted muscle cells, some myofilaments of the A band passed between the dense bodies of the Z band. T-system tubules were evident and formed dyads with sarcoplasmic reticulum. The structural integrity of the oviduct was maintained by connective tissue strands between muscles and the epithelial sheath. Many of these strands consisted of basal lamina. Epithelial cells that line the inner sheath of the oviduct were cuboidal. In transection, these cells revealed a prominent apical microvillar region with large numbers of mitochondria and an extensive infolding of the basal plasma membrane.

Animals↗
PubMed1992

Some pharmacological properties of the oviduct muscularis of the stable fly Stomoxys calcitrans.

1. Spontaneous and rhythmic contractions were measured in 80% of the preparations of the stable fly oviduct which were separated from the central nervous system and other tissues. Measurements of the changes in the amplitude and frequency of contractions and changes in the baseline tonus were taken separately, even though they often occurred together during chemical treatments. 2. L-glutamate, at a concentration of 10(-4) to 10(-3) M, caused an increase in the frequency of contractions and in muscle tonus. Contraction frequency showed the highest percentage of change while amplitude and tonus had lower values. 3. The excitation threshold for proctolin on the oviduct was between 10(-13) and 10(-10) M. The initial responses to the peptide showed increases in the amplitude, frequency, and tonus of muscle contractions. However, tonic changes dominated the response profile when the concentration reached 10(-10) or 10(-9) M. In 12 experiments in which the oviduct was exposed to 10(-7) M leucomyosuppressin, no change in the amplitude, frequency, or tonus of muscle contractions was detected. 4. Octopamine caused an inhibition of spontaneous muscle contractions of the oviduct. Spontaneous contractions showed a graded drop in activity over the concentration range tested (10(-8)-10(-6) M). Also 57% of the preparations tested showed a substantial drop in baseline tonus after the addition of octopamine. 5. Stable fly oviducts exposed to extracts from the male reproductive tract showed a noticeable change in the amplitude frequency and tonus of muscle contraction at levels of 2 to 3 equivalents.

Animals↗
PubMed1991

Action of taurine, 3-aminopropanesulfonic acid, and GABA on the hindgut and heart of the cockroach, Leucophaea maderae.

Taurine, glycine, glutamate, and gamma-aminobutyric acid (GABA) were all present in concentrations of greater than 1% of the total free amino acid content in the brain, thoracic, and abdominal ganglia of Leucophaea maderae. Hemolymph, subesophageal ganglia, and hindgut had substantial amounts of glutamate and glycine, but less than 0.3% taurine or GABA. Taurine, 3-aminopropanesulfonic acid (3-APS), cysteine-sulfinic acid (CSA), and GABA each had myotropic activity on the isolated cockroach hindgut, with 3-APS having the most consistent effect (ED50 = 0.63 mM), while taurine and CSA activities were similar to that of GABA on the hindgut. Both taurine and 3-APS had anti-arrhythmic effects on semi-isolated heart preparations of L. maderae, while GABA was inhibitory and induced arrhythmia. Bicuculline was antagonistic to the effects of GABA, taurine, and 3-APS on the hindgut, and induced arrhythmia in heart preparations; this arrhythmia was reversible by taurine, but not by GABA or 3-APS.

Amino Acids↗
PubMed1991

Comparative effects of leucomyosuppressin on the visceral muscle systems of the cockroach Leucophaea maderae.

1. Leucomyosuppressin (LMS) did not inhibit the spontaneous contractions of visceral muscles of the cockroach Leucophaea maderae uniformly as a group but rather showed a selective suppression of activity in the foregut and hindgut. The threshold of LMS inhibition for these organs was 10(-11) M for the foregut and 3 x 10(-11) M for the hindgut. The maximum response for each organ was generally recorded at 2.4 x 10(-8) M. 2. Both the heart and the oviduct were 100-1000 times less sensitive to LMS than either the foregut or the hindgut. Although the responses of the heart to LMS (10(-9) to 10(-8) M) were somewhat inconsistent, the myocardium showed a reduction in either the amplitude or frequency of contractions in 75% of the preparations tested. The oviduct showed the lowest level of responsiveness of all the muscles tested. Even at a concentration of 10(-7) M LMS, the amplitude and frequency of contractions showed no more than a 58% inhibition. 3. Desensitization to LMS was observed in three of the four muscle types tested. The phenomenon occurred in 37% of the foreguts, 34% of the hindguts and 54% of the heart preparations tested. The results of this study show that each visceral muscle type has its own unique response profile to LMS and support the idea that peptides may be multifunctional regulators.

Animals↗
PubMed1990

Comparative pharmacological actions of leucokinins V-VIII on the visceral muscles of Leucophaea maderae.

1. Leucokinins V-VIII (Lem-K-V to VIII) did not activate visceral muscles of the cockroach Leucophaea maderae uniformly as a group but rather showed a selective action on the muscles of the hindgut. This organ showed a contractile response to all of the leucokinins at 3 x 10(-10) M that was 2-20% above the mean level of spontaneous activity. The maximum response for each peptide was recorded at 2.1 x 10(-7) M. 2. Both the foregut and the oviduct were 100- to 1000-fold less sensitive than the hindgut, and each of the former required more than 10(-8) M to elicit a detectable excitation. The heart, by comparison, did not respond to any of these peptides. 3. The leucokinins caused a protracted excitation of contractile events in the hindgut that lasted for more than 60 min. Moreover, all four peptides evoked contractions from hindguts after membrane depolarization with 158 mM potassium. These results suggest that nonsynaptic receptors for the peptides exist in visceral muscle.

Amino Acid Sequence↗
PubMed1989

Pharmacological actions of a new class of neuropeptides, the leucokinins I-IV, on the visceral muscles of Leucophaea maderae.

1. Leucokinins I-IV did not activate visceral muscles uniformly as a class but rather showed a selective action on the muscles of the hindgut. This organ showed a contractile response to all of the leucokinins at 3 x 10(-10) M that was 5-10% above the mean level of spontaneous activity. The maximum response for each peptide was recorded at 2.1 x 10(-7) M. 2. Both the foregut and the oviduct were 100-1000 fold less sensitive than the hindgut, and each of the former organs required more than 10(-8) M to elicit a detectable excitation. The heart, by comparison, failed to give consistent responses with any of the peptides. 3. The leucokinins caused a protracted excitation of contractile events in the hindgut that lasted for more than 60 min. Moreover, all four peptides evoked contractions from hindguts after membrane depolarization with 158 mM potassium. 4. This result shows that nonsynaptic receptors for the peptides exist in visceral muscle. The leucokinins showed no evidence of facilitating the reentry of calcium into calcium depleted hindgut preparations.

Animals↗
PubMed1986

Leucosulfakinin-II, a blocked sulfated insect neuropeptide with homology to cholecystokinin and gastrin.

A sulfated neuropeptide [pGlu-Ser-Asp-Asp-Tyr(SO3H)-Gly-His-Met-Arg-Phe-NH2], with a blocked N-terminus and related to the undecapeptide leucosulfakinin, has been isolated from head extracts of the cockroach, Leucophaea maderae. It exhibits sequence homology with the hormonally-active portion of vertebrate hormones cholecystokinin, human gastrin II and caerulin. This peptide, termed leucosulfakinin-II, shares a common C-terminal heptapeptide fragment with leucosulfakinin and a comparison of the two sequences provides an assessment of the importance of the constituent amino acids to biological activity. Leucosulfakinin-II shows a greater resemblance to cholecystokinin than does leucosulfakinin. Leucosulfakinin-II and leucosulfakinin are the only two reported invertebrate sulfated neuropeptides. As with leucosulfakinin, the intestinal myotropic activity of leucosulfakinin-II is analogous to that of gastrin and cholecystokinin. The sequence homology between the leucosulfakinins and the vertebrate hormones, as well as their analogous myotropic activity, suggest that gastrin/cholecystokinin-like neuropeptides are not confined to vertebrates, but also occur in invertebrates.

Amino Acid Sequence↗
PubMed1986

Active fragments and analogs of the insect neuropeptide leucopyrokinin: structure-function studies.

Evaluation of analogs of the blocked insect myotropic neuropeptide leucopyrokinin (LPK) has demonstrated its relative insensitivity to amino acid substitution in the N-terminal in contrast to the C-terminal region. Truncated analogs of LPK without the first, second, and third N-terminal amino acids retain a significant 144%, 59% and 30% of the activity of the parent octapeptide, respectively. The [2-8]LPK analog is the first fragment of an insect neuropeptide to exhibit greater activity than the parent hormone. In contrast, truncated analogs of the insect myotropic, proctolin, exhibit little or no activity. The pentapeptide fragment Phe-Thr-Pro-Arg-Leu-NH2 has been identified as the active core of LPK.

Amino Acid Sequence↗
PubMed1986

Primary structure and synthesis of a blocked myotropic neuropeptide isolated from the cockroach, Leucophaea maderae.

A peptide which stimulates the contractile activity of the cockroach hindgut was isolated from head extracts of the cockroach, Leucophaea maderae. The inability of aminopeptidase M to degrade the peptide and the presence of glutamic acid in the hydrolysate suggested N-terminal blocking by pyroglutamic acid. The N-terminal pGlu was removed enzymatically and the unblocked fragment was sequenced with an automated gas-phase peptide sequencer. The structure determined (pGlu-Thr-Ser-Phe-Thr-Pro-Arg-Leu-NH2) was synthesized and shown to be both chemically and biologically identical with the natural product.

Amino Acid Sequence↗
PubMed1985

Distribution of calmodulin in insects as determined by radioimmunoassay.

The distribution of calmodulin in 11 separate tissues of the cockroach Leucophaea maderae was determined by radioimmunoassay. The highest levels of this protein were found in Malpighian tubules, visceral muscle and the central nervous system. Distribution of calmodulin was also determined for the following insect species: Apis mellifera, Canthon imitator, Heliothis zea (larvae) and Periplaneta americana. Abdominal tissues contained the highest levels of the calcium binding protein, while lesser amounts were found in the thorax and head. The detected levels of calmodulin suggest that this protein serves as an important regulator of biochemical functions in the viscera and nervous system of insects.

Animals↗