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D W Cooper

Publications and source records attributed to D W Cooper.

At least 55 records · Page 3Linked to original sources
PubMed1998

cDNA cloning of luteinizing hormone subunits from brushtail possum and red kangaroo.

Luteinizing hormone (LH) plays an important role in the reproductive cycles of all mammals. There is a large amount of both nucleotide and amino acid sequence data available for LH from eutherian mammals, but little is known about the primary structure of LH in marsupials. We have used consensus PCR primers to generate specific probes for screening pituitary cDNA libraries and report the cloning of the cDNAs encoding the alpha-subunit of LH (also shared by a number of other glycoprotein hormones) and the LH-specific beta-subunit, from the common brushtail possum, Trichosurus vulpecula, and the red kangaroo, Macropus rufus. Southern blotting experiments indicated that both genes are probably present as single copies. Comparison of the deduced marsupial protein sequences with homologous sequences from other vertebrates revealed a high degree of conservation, especially for the alpha-subunit. These sequences represent the first complete primary structures for a marsupial glycoprotein hormone to have been elucidated.

Amino Acid Sequence↗
PubMed1998

Molecular cloning of the cDNA encoding the constant region of the immunoglobulin A heavy chain (C alpha) from a marsupial: Trichosurus vulpecula (common brushtail possum)

A cDNA encoding the brushtail possum immunoglobulin A heavy chain constant region (C alpha) was isolated by screening a mesenteric lymph node cDNA library with a porcine C alpha exon 3 probe. The larger of the two positive clones isolated (Tv4a) consisted of 1325 bp of possum cDNA that included an open reading frame of 1191 bp. Its deduced amino acid sequence had a high degree of sequence identity with known eutherian C alpha sequences. This clone appears to encode the entire possum IgA heavy chain constant region. The possum C alpha sequence had a nucleotide sequence identity of 57.7% with porcine C alpha, 51% with mouse C alpha, 46.7% with dog C alpha and 45.9% with human C alpha2. The corresponding amino acid identities were 46.7, 45.6, 49.4 and 49%, respectively.

Amino Acid Sequence↗
PubMed1998

Cloning of the red kangaroo (Macropus rufus) follicle stimulating hormone beta subunit.

The cDNA encoding the follicle stimulating hormone beta subunit (FSH-beta) was isolated from a red kangaroo pituitary cDNA library by using a porcine probe and the nucleotide sequence for the coding region was determined. The highest degree of deduced amino acid sequence identity (91%) was observed between the red kangaroo and another marsupial, the brushtail possum (Trichosurus vulpecula), followed by eutherian species (76%, 75% and 74%, respectively, for pig, mouse and sheep). Based on the deduced red kangaroo FSH-beta amino acid sequence, putative antigenic sites have been identified that may prove useful for studying the hormonal control of reproduction in marsupials.

Amino Acid Sequence↗
PubMed1998

Developmental expression of the androgen receptor during virilization of the urogenital system of a marsupial.

In the marsupial tammar wallaby, virilization begins approximately 3 wk after the onset of testosterone synthesis. In the eutherian mammal, in contrast, the onset of virilization of the male urogenital tract occurs shortly after the onset of androgen synthesis. Androgen action requires the presence of the androgen receptor to mediate a response in target tissues. We therefore investigated the developmental expression of the androgen receptor (AR) in both sexes of the tammar wallaby. AR gene transcript was detected in fetal gonad and brain as early as Day 19 of the 26.5-day gestation, 7 days earlier than the first rise in testicular testosterone (Days 0-5 postpartum [p.p.]). Immunoreactive AR was identified in the male urogenital sinus (UGS) 2 days before birth and in the female UGS and mammary glands by the day of birth. AR was present in the UGS, vagina, and prostate until Day 152 p.p., the oldest age examined. AR was identified in the gubernaculum testis at Day 2 p.p. and became more abundant by Day 32. In the phallus of both sexes, AR was identified by Day 4 p.p. and until Day 157, the oldest age examined. AR was not detected in the scrotum at any age from the day of birth to Day 157. Maturation of the phallus, wolffian duct, and epididymis was marked by appearance of epithelial immunostaining. AR was localized in the epithelium of the UGS in females by Day 50 p.p. but was not found in the epithelium of the male UGS up to Day 152 p.p., the oldest examined. AR were found in the mesenchyme of the UGS of male and female tammars 3-4 wk before virilization is first evident in the male at Day 25 p.p. We conclude that the presence of AR is not the initiating signal for virilization of the UGS in this marsupial male.

Amino Acid Sequence↗
PubMed1997

Angiotensinogen gene variation in a population case-control study of preeclampsia/eclampsia in Australians and Chinese.

Preeclampsia/eclampsia (PE/E) is a common disease of human pregnancy with a strong genetic component. The etiology of PE/E is unknown. Two recent reports indicated that the angiotensinogen gene (AGT) could be involved in susceptibility to PE/E. We performed a population-based case-control study in Australian and Chinese populations to investigate whether AGT is a good candidate gene for PE/E. A microsatellite polymorphism within AGT was typed as well as a molecular variant T235 (Met-->Thr) of AGT using allele-specific PCR and allele-induced restriction site PCR. The allele distributions of the microsatellite and the variant T235 of AGT were significantly different between the two ethnic groups. However, no significant allele associations were found with disease when comparing PE/E patients and controls in Australian or Chinese populations, which is in contrast to the two earlier reports. The results suggest that the contribution of AGT to the occurrence of PE/E is small, if anything, and is not constant across populations.

Alleles↗
PubMed1997

Development of the lymphoid tissues of the tammar wallaby Macropus eugenii.

A study has been made of the development of four lymphoid tissues from birth to maturity in the tammar wallaby Macropus eugenii--the cervical and thoracic thymus, lymph nodes and gut-associated lymphoid tissue (GALT). The development of these tissues in the tammar wallaby is similar to that in two other marsupials, the quokka Setonix brachyurus and the Virginian opossum Didelphis virginiana. Lymphocytes were first detected in the cervical thymus of the tammar at Day 2 post partum and in the thoracic thymus at Day 6. They were subsequently detected in lymph nodes at Day 4 and in the spleen by Day 12 but were not apparent in the GALT until around Day 90 post partum. By Day 21, the cervical thymus had developed distinct areas of cortex and medulla and Hassall's corpuscles were apparent. The maturation of other tissues followed with Hassall's corpuscles in the thoracic thymus by Day 30 and nodules and germinal centres in the lymph nodes by Day 90. Measurement of immunoglobulin G concentrations in the serum of young animals indicated a rise in titre around Day 90 post partum, correlating with the apparent maturation of the lymphoid tissues.

Aging↗
PubMed1997

SRY and karyotypic status of one abnormal and two intersexual marsupials.

An intersexual agile wallaby (Macropus agilis) with a penis, a pouch and four teats had a sex-chromosome constitution of XXY in lymphocytes and cultured fibroblasts; the sex-determining region Y (SRY) gene was present, consistent with the presence of a testis. An intersexual eastern grey kangaroo (Macropus giganteus) with a small empty scrotum and no penis, and an abnormal red kangaroo (Macropus rufus) with no penis, pouch or teats, both had XX sex-chromosome complements; the SRY gene was not present, consistent with testis absence. The agile wallaby and grey kangaroo described here provide further evidence that scrotal development in marsupials is independent of the Y chromosome. The cause of the abnormalities in the XX individuals cannot be determined until candidate genes are identified. These animals provide a basis for further genetic studies into marsupial intersexuality and sex differentiation.

Animals↗
PubMed1997

Does intrathecal fentanyl produce acute cross-tolerance to i.v. morphine?

We have examined the hypothesis that intrathecal fentanyl at operation can increase postoperative i.v. morphine requirements. We studied 60 patients undergoing Caesarean section. All received intrathecal 0.5% plain bupivacaine 2 ml combined with either fentanyl 0.5 ml (25 micrograms) (group F) (n = 30) or normal saline 0.5 ml (group S) (n = 30). In addition, 10 ml of an extradural solution (fentanyl 1 ml (50 micrograms) combined with 0.5% bupivacaine 9 ml) was administered after delivery. Extradural solution was only given before delivery if the intrathecal injection failed to produce a block above T6 or the patient required further analgesia. Postoperative analgesia was provided with i.v. morphine patient-controlled analgesia. At operation, intrathecal fentanyl reduced the need to administer extradural solution before delivery, increased the anaesthetist's satisfaction with analgesia and reduced nausea, but increased pruritus. Up to 6 h after delivery there was no difference in postoperative morphine requirements or pain scores. Between 6 h and 23 h there was a 63% increase in morphine requirements in group F. We consider the most likely explanation for this finding to be that intrathecal fentanyl induced acute spinal opioid tolerance.

Analgesia, Patient-Controlled↗
PubMed1997

A genomewide linkage study of preeclampsia/eclampsia reveals evidence for a candidate region on 4q.

Preeclampsia (PE) and eclampsia (E) are potentially life-threatening conditions that can occur during human pregnancy. Generally considered to be different degrees of severity of the same disease process, the PE/E syndrome is thought to be predominantly genetic in origin, although its exact etiology and genetics are not fully understood. Here we report results of a genomewide linkage search for the gene(s) responsible for susceptibility to PE/E, using 15 informative pedigrees and 90 polymorphic DNA markers from all autosomes. Because of uncertainties concerning inheritance and diagnosis, four different models that assume maternal gene expression have been used to carry out LOD-score analysis. The region between D4S450 and D4S610 (2.8 cM) on the long arm of chromosome 4 was identified as a strong candidate region for a PE/E-susceptibility locus. The maximum multipoint LOD score within this interval was 2.9. Analysis of markers in the region around D4S450 and D4S610 by the affected-pedigree-member method also supported the possibility of a susceptibility locus in this region. However, to verify or exclude definitively linkage to this region, other groups of PE/E pedigrees will be required.

Australia↗
PubMed1996

Development of the blood-forming tissues of the tammar wallaby Macropus eugenii.

The development of the haematopoietic tissues of the tammar wallaby Macropus eugenii follows a similar pattern to that observed in eutherian and other metatherian mammals. At birth, the liver appears to be the only site of haematopoiesis with significant numbers of neutrophils and stem cells present in the circulation. By Day 3, the spleen shows limited haematopoietic activity and by Day 12 contains areas of erythroid and myeloid cells. At two weeks after birth, the haematopoetic activity in the liver declines and small areas of haematopoiesis are apparent in the bone marrow. By the end of the first month, the bone marrow appears to be the major site of haematopoiesis.

Animals↗
PubMed1996

Patient-controlled extradural analgesia with bupivacaine, fentanyl, or a mixture of both, after Caesarean section.

In this randomized, double-blind study of 60 patients, we have assessed the analgesic efficacy of extradural bupivacaine and extradural fentanyl, either alone or in combination, after Caesarean section. Patients received 0.1% bupivacaine (group B), fentanyl 4 micrograms ml-1 (group F) or 0.05% bupivacaine combined with fentanyl 2 micrograms ml-1 (group BF) by patient-controlled extradural analgesia (PCEA). Adding fentanyl to bupivacaine reduced the dose of bupivacaine by up to 68%, improved analgesia at rest and decreased PCEA use. Motor and sensory block were decreased, but there was more pruritus. Overall patient satisfaction was increased. Adding bupivacaine to fentanyl reduced the dose of fentanyl by up to 57% without altering pain scores or PCEA use. Sensory block increased but pruritus did not decrease. Bupivacaine 0.05% produced clinically significant leg weakness in three patients. Overall patient satisfaction was not altered. There was a significant additive analgesic effect between 0.05% bupivacaine and fentanyl but no clinical benefit was demonstrated from using the combination compared with fentanyl alone for this group of postoperative patients.

Adult↗
PubMed1996

Genetic variation in Australian Merino sheep.

Variation at 22 gene loci was investigated in a flock of Australian Merino sheep using restriction fragment length polymorphism (RFLP) analysis. Polymorphism was observed at 20 loci, including loci for wool keratin, hormone and immunoglobulin light chain genes. Eleven loci yielded unambiguous genotypes suitable for population data analysis. Average heterozygosity, determined from these and two monomorphic loci, was estimated as 0.107 (SE = 0.024). Average heterozygosity excluding all monomorphic data as estimated at 0.377 (SE = 0.031), which is comparable with human RFLP heterozygosities for loci chosen in the same way that we selected sheep loci.

Animals↗
PubMed1996

Close linkage between RNR and GPD genes on the tammar wallaby (Macropus eugenii) X chromosome.

No recombination was detected between two X-linked loci, RNR (Xp) and GPD (Xq), among 69 backcross progeny of two distantly related tammar wallaby (Macropus eugenii) subspecies. RNR loci are not dosage compensated, whereas the GPD locus is subject to the paternal X chromosome inactivation system that characterises female marsupials. The border of the region controlled by the marsupial X chromosome inactivation system has therefore been shown to lie between RNR and GPD.

Animals↗
PubMed1995

Extradural fentanyl for postoperative analgesia: predominant spinal or systemic action?

This randomized, double-blind study of 40 patients was designed to determine if the predominant analgesic effect of extradural fentanyl is mediated by a direct spinal action or an indirect systemic one. After Caesarean section, postoperative analgesia was provided for 24 h by patient-controlled extradural analgesia (PCEA group) or by patient-controlled i.v. analgesia (PCIVA group). Both groups received a bolus dose of fentanyl 20 micrograms with a 10-min lockout interval. In the PCIVA group, nine patients stopped early (compared with none in the PCEA group) because of inadequate analgesia. Mean visual analogue pain scores (0-100 mm) at 8 and 12 h were lower for PCEA (23 (sd 13) mm at rest, 31 (23) mm on coughing) than for PCIVA (50 (25) mm at rest, 67 (24) mm on coughing) (P < 0.0005). The mean dose of fentanyl self-administered between 4 and 8 h was lower in the PCEA group (38 (sd 30) micrograms h-1) compared with the PCIVA group (59 (27) micrograms h-1) (P < 0.05). Our results support the hypothesis that the predominant analgesic effect of extradural administration of fentanyl is mediated by a direct spinal action rather than an indirect action from systemic absorption.

Adolescent↗