Search PubMed⌕ Search

Biomedical subjects

K J Dawson

Publications and source records attributed to K J Dawson.

26 records · Page 2Linked to original sources

Results of a recently instituted programme of thrombolytic therapy in acute lower limb ischaemia.

Twenty-eight patients with acute lower limb ischaemia received low dose intra-arterial thrombolytic therapy over a 2-year period. Eighteen patients received streptokinase and ten patients received recombinant tissue plasminogen activator (rTPA). Indications included arterial thromboemboli and graft failures. Mean ischaemic times were similar in both groups. Treatment time to achieve lysis was significantly less with rTPA (P less than 0.01). Subsequent vascular procedures, including angioplasty or reconstruction, were undertaken in 36 per cent of patients. Arterial puncture site bleeding occurred in eight (29 per cent) patients. Three (11 per cent) patients suffered rethrombosis after initial successful lysis. All rethromboses were successfully lysed with rTPA. There were two major amputations. Five (18 per cent) patients died, all lytic failures in the streptokinase treatment group. There were no cerebral haemorrhagic events and no patient died as a result of thrombolytic therapy. Good clinical outcome was obtained in nine of 18 patients treated with streptokinase and in nine of ten patients treated with rTPA. Intra-arterial thrombolysis provides effective therapy with high rates of limb salvage and a low mortality rate. This study suggests that rTPA may be a more effective agent, causing less morbidity, than streptokinase.

Acute Disease↗

Improvement of in vitro fertilisation after treatment with buserelin, an agonist of luteinising hormone releasing hormone.

Treatment with buserelin, an agonist of luteinising hormone releasing hormone, and human menopausal gonadotrophin was compared with the conventional treatment of clomiphene citrate and human menopausal gonadotrophin in the outcome of in vitro fertilisation. Seventy seven infertile women had 83 cycles of treatment with buserelin and human menopausal gonadotrophin, and concurrently another 328 infertile women were treated with clomiphene citrate and human menopausal gonadotrophin. Seven (8%) cycles were cancelled owing to inadequate super-ovulation or ovarian hyperstimulation in the women receiving buserelin and 103 (31%) were cancelled because of poor follicular development in those receiving clomiphene citrate. The mean number of oocytes recovered was significantly higher with buserelin (9.5 (SD 4.5) v 5.5 (2.2)) as was the mean number of embryos obtained (4.3 (2.4) v 2.9 (1.7)). Significantly more women who had an embryo transfer became clinically pregnant after treatment with buserelin (53% (30/57) v 30% (48/159), or 36% v 14% of treatment cycles). Altogether 33% (10) of pregnancies in women treated with buserelin were multiple compared with 23% (11) in those treated conventionally. Of the 17 completed pregnancies in women treated with buserelin, 11 resulted in the birth of live babies (eight singletons, two sets of twins, and one set of triplets) and six failed, five before 12 weeks' gestation and one at 22 weeks. The 13 continuing pregnancies (32 weeks) were eight singletons, two sets of twins, and three sets of triplets. Of the 48 completed pregnancies in women treated with clomiphene citrate, 35 resulted in the birth of live babies (26 singletons, five sets of twins and four sets of triplets) and 13 failed, eleven before 12 weeks' gestation and two by 27 weeks. Buserelin increased the chance of pregnancy after in vitro fertilisation compared with conventional treatment, but the risk of multiple pregnancy may be increased.

Buserelin↗

Elongated cells derived from rat mammary cuboidal epithelial cell lines resemble cultured mesenchymal cells in their pattern of protein synthesis.

Two-dimensional gel electrophoresis has been used to identify polypeptide patterns characteristic of rat mammary cuboidal epithelial cells or mesenchyme-derived cells. Elongated cells and cell lines derived from cloned cuboidal epithelial cells in culture possess a polypeptide pattern which resembles that of the cultured mesenchymal cells rather than that of the cuboidal epithelial cells from which they were derived. These elongated converts also resemble cultured mesenchymal cells in possessing a Triton-insoluble matrix in which vimentin and not prekeratin predominates.

Animals↗

Control of protein synthesis in cuboidal rat mammary epithelial cells in culture. Changes in gene expression accompany the formation of elongated cells.

The cuboidal rat mammary tumour cell line, Rama 25, spontaneously converts to elongated cells during culture. The polypeptides synthesised by the two morphological forms are compared by two-dimensional polyacrylamide gel electrophoresis. In addition to major changes in the intermediate filament proteins, there are two abundant acidic polypeptides of molecular weights 9000 and 15500, which are synthesised by the elongated cells but which are not detectable in the cuboidal cells. When mRNA preparations isolated from the cuboidal and elongated cells are translated in the reticulocyte lysate, the patterns of radioactive products resemble the patterns of polypeptides synthesised in the intact cells. Translation products corresponding to the 9000-Mr and 15500-Mr polypeptides are synthesised when mRNA from elongated cells is translated, but are not synthesised when mRNA from cuboidal cells is translated. Evidence is presented that the appearance of these two proteins represents a change in gene expression between the two cell types and that control is exerted prior to mRNA translation.

Animals↗

In-vitro development of preimplantation embryos recovered from IUD-bearing mice.

Embryos were collected from the oviducts and uterine horns of mice bearing a unilateral IUD and of non-IUD control mice at various times p.c., examined for the presence or absence of polymorphonuclear leukocytes (PMNLs) and cultured. Normal numbers of embryos were obtained on the IUD side at 48 h p.c., but reduced numbers were recovered at 60-66 and 72 h p.c. The numbers of embryos that hatched from those collected from control, IUD-bearing and contralateral non-IUD bearing tracts were, respectively, 81, 29 and 36% for 48-h embryos, 78, 47 and 51% for 60-66-h embryos, and 88, 47 and 54% for 72-h embryos. At 48 h and 60-66 h p.c. the arrest of development occurred at the expanded blastocyst stage, but at 72 h p.c. some compacted morulae were affected. Some embryos associated with PMNLs at collection developed normally when the PMNLs were dispersed before culture. An initial association with leukocytes is therefore not necessarily detrimental to the subsequent in-vitro development of the embryo in mice.

Animals↗