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Biomedical subjects

A M Burgess

Publications and source records attributed to A M Burgess.

At least 19 recordsLinked to original sources
PubMed1995

Return to well-being and function after infrainguinal revascularization.

PURPOSE: The purpose of this study was to assess functional status, well-being, and symptom relief of patients after infrainguinal revascularization for severe peripheral vascular disease. METHODS: Two questionnaires were used to assess symptoms, functional status, and well-being before operation and 6 months after operation. Sociodemographics, comorbidities, indications for surgery, graft location, and morbidity, mortality, patency, and limb salvage rates were obtained via vascular registry. RESULTS: Of 318 patients who underwent revascularization over a 1-year period, 276 patients were asked to complete the questionnaires. Of the 156 patients who completed both questionnaires, mean age was 66 years, 67% were men, 84% had diabetes mellitus, and 83% had various heart-related conditions. Mean length of stay was 15.3 days. Distal graft sites were popliteal (29%), tibial/peroneal (40%), and pedal/plantar (31%). The operative morbidity rate was 21%, the cumulative primary graft patency rate was 93%, the cumulative secondary graft patency rate was 95%, and the limb salvage rate was 97% at 6 months. At follow-up, improved functioning of instrumental activities of daily living, mental well-being, and vitality were reported. Symptoms of calf cramping and toe or foot pain when walking and at rest were also improved. Sores or ulcers improved, but leg swelling did not. The only independent predictor of improved function and well-being was the patients' perception of their status at baseline: those patients who functioned better before operation reported improved function and well-being at 6 months. Only 45% of patients reported feeling "back to normal" at 6 months. CONCLUSION: Reported health status at baseline was a predictor of improved function, mental well-being, and resolution of symptoms after infrainguinal revascularization. Expected return to "normal" may take longer than 6 months.

Activities of Daily Living↗
PubMed1995

Dorsalis pedis arterial bypass: durable limb salvage for foot ischemia in patients with diabetes mellitus.

PURPOSE: Although the technical feasibility of pedal artery bypass for limb salvage is now well established, questions remain about its most appropriate use and its long-term durability. METHODS: We reviewed our experience over an 8-year period in 367 consecutive patients undergoing 384 vein bypass grafts to the dorsalis pedis for limb salvage. RESULTS: Ninety-five percent of the patients had diabetes mellitus. Infection complicated ischemia at initial presentation in 55.2% of patients. The preoperative arteriogram demonstrated a patent dorsalis pedis in 362 extremities (92.8%). Four hundred two patients underwent exploration for bypass, including 29 patients without demonstrated arteries on the arteriogram but audible pedal Doppler signals. Successful bypasses were carried out in 357 of 362 cases, where preoperative arteriography demonstrated a patent dorsalis pedis artery (98.6%), 16 of 28 cases explored on the basis of a Doppler signal alone (57%), and 11 of 12 patients where angiographic status was unknown. All procedures were performed with vein: in situ 38.5%, reversed 29%, nonreversed 18%, arm vein 7%, and composite vein 8%. Inflow was taken from the common femoral artery in 34%, superficial femoral or popliteal arteries in 60%, a previously placed graft in 5%, and a tibial artery in 1%. There were seven perioperative deaths (1.8%) and 21 myocardial infarctions (5.4%). Twenty-nine grafts failed within 30 days (7.5%), but 19 were successfully revised. Eight of the 10 failed grafts resulted in major amputation (80%). Over the remaining study period, there were 39 additional graft failures, of which 17 were successfully revised, and 17 additional major amputations. Actuarial primary and secondary patency and limb salvage rates were 68%, 82%, and 87%, respectively, at 5 years' followup. The actuarial patients survival rate was 57% at 5 years. Patency rates were similar for in situ and translocated saphenous vein grafts. CONCLUSIONS: Dorsalis pedis arterial bypass is an effective limb salvage procedure with long-term durability comparable to distal vein grafts placed into more proximal arteries.

Arteries↗
PubMed1995

A quantitative investigation of gonadal feminization by diethylstilboestrol of genetically male embryos of the quail Coturnix coturnix japonica.

The effect of diethylstilboestrol on gonad development in quail embryos has been quantitatively analysed. Quail embryos at 4 days of incubation were treated with diethylstilboestrol (DES), using the egg dipping method. At 10 days of incubation, embryos were removed and killed by decapitation. Tissues were prepared for chromosome analysis, and the parts of the abdomen containing the gonads were prepared for serial sectioning and quantitative assessment. Left gonads of DES-treated male embryos resembled ovaries histologically, while their right gonads were markedly reduced in size. Right gonads of DES-treated female embryos were also further reduced by treatment with DES. There was no statistically significant effect by DES treatment on the size of left gonads, although the ratio of left compared with right gonadal volumes was highly significant. Since, in birds, the left embryonic gonad has ambisexual potential, while the potential of the right gonad is exclusively masculine, these results exemplify the adverse effect exerted by oestrogen on male sexual development in vertebrates.

Animals↗
PubMed1993

Improved quality of diabetic foot care, 1984 vs 1990. Reduced length of stay and costs, insufficient reimbursement.

Ischemic foot ulceration in the diabetic patient is a source of great physical and emotional strain for the patient and represents a significant financial burden for the health care system responsible for the cost of such care. Limb salvage remains the primary therapeutic goal; yet, fiscal constraints imposed by diagnosis related group-based reimbursement systems require maximal cost efficiency in the care process. Between 1984 and 1990, the changes in our team management approach to this problem, emphasizing aggressive surgical revascularization of threatened limbs, have improved the quality of care and dramatically reduced the major and minor amputation rate. In the process, we have reduced the length of hospital stay and the overall cost of care. Despite this improvement in outcome and efficiency, Medicare reimbursement remains insufficient, with an average loss of $7480 per admission.

Aged↗
PubMed1993

Gonadal sex differentiation in embryos and neonates of the marsupial, Monodelphis domestica: arrest of testis development in postterm embryos.

Growth and histological differentiation were studied in 8 litters of embryos and 4 litters of neonate grey short-tailed opossums, Monodelphis domestica. The embryonic litters included 2 that had passed their expected birth date, and whose weights exceeded the usual birthweights; we refer to these litters as 'postmature'. There was an abrupt increase in the growth rate of XY gonads after birth, but this was not seen in XX gonads. Although there was evidence of testicular differentiation in XY gonads on the day before the expected birth, testicular differentiation was found to be blocked in postmature litters. The growth of XX gonads in postmature embryos was not affected. In view of evidence that exogenous oestrogens feminise the gonads of genetic males in some species of marsupials including Monodelphis domestica, the question arises whether oestrogen is responsible for the failure of testes to continue their development in utero. We suggest that the ability of functional testes to develop in the presence of oestrogen may be a fundamental requirement distinguishing eutherian mammals from other vertebrates, including marsupials.

Animals↗
PubMed1990

Gonadal sex differentiation in the neonatal marsupial, Monodelphis domestica.

A quantitative and histological study of the gonads of newborn grey short-tailed opossums, Monodelphis domestica, is described. The pups were karyotyped, and comparisons were made within litters segregating for XX and XY sex chromosomes. A total of four litters including 25 pups were available. On the day of birth, developing testes were significantly larger than the ovaries of litter mates, and testes could be histologically distinguished by the formation of sex cords and a tunica albuginea. The data suggest that in this marsupial species gonadal differentiation may be initiated in utero.

Animals↗
PubMed1989

Teratogenic effects of some calcium channel blocking agents in Xenopus embryos.

Xenopus embryos, treated for three days from the early cleavage stage with the calcium channel blocking drugs nifedipine, diltiazem, verapamil or nicardipine continue to develop in water. By the seventh day many developmental abnormalities appear, the most reproducible affecting the central nervous system, failure of forebrain development, synophthalmia and neural tube defect. Other anomalies include failure of mandibular growth and malrotation of the gut. Failure of water and electrolyte transport are indicated by severe oedema in some animals. The defects appear to relate to calcium ion antagonism, and provide a pharmacological model for some forms of teratogenesis in which large populations can be studied readily.

Abnormalities, Drug-Induced↗
PubMed1988

Phase II study of AMSA alone and in combination with DTIC in patients with metastatic melanoma.

A randomized phase II study of AMSA (amsacrine) alone and AMSA combined with DTIC (dacarbazine) was carried out in 31 and 39 patients with metastatic melanoma respectively. AMSA was used at a starting dose of 40 mg/m2/day X 3 days with escalation to 50-60 mg/m2/day X 3 days in 8 pts. For AMSA + DTIC the starting dose was: AMSA 30 mg/m2/day X 3 days; DTIC, 800 mg/m2 X 1 day. Additionally, seven pts received AMSA in a similar dose schedule but DTIC was used in a 5-day schedule of 250 mg/m2/day. Twenty-five patients were evaluable for response in the AMSA group and 36 in the AMSA + DTIC group. The objective response to AMSA included 1(4%) partial response compared with 11 complete or partial responses (30%) with AMSA + DTIC therapy. The median lowest absolute granulocyte count was 1100/microliters in AMSA group compared with 1000/microliters in the AMSA + DTIC group. Severe neutropenia of less than 500 granulocytes/microliter was observed in 5 pts in the AMSA group compared with 13 pts in the AMSA + DTIC group. We concluded that AMSA has no significant activity against melanoma, although the combination of AMSA + DTIC seemed to be more active than DTIC alone.

Adult↗
PubMed1988

Identification of the E1fE1k cholinesterase genotype.

A family segregating for the A, F, and K alleles at cholinesterase locus 1 is described. This work, undertaken after the proband suffered prolonged apnoea after the use of suxamethonium during the delivery of her third child, resulted in the identification of the E1fE1k genotype in her oldest son.

Cholinesterases↗
PubMed1988

Ultrastructural study of contacts between cells of the dorsal ectoderm and chordamesoderm during gastrulation in Xenopus laevis.

In gastrulae of Xenopus laevis, various morphological types of intercellular approximation occur between the dorsal ectoderm and chordamesoderm. Ruthenium red staining reveals that in some areas the glycocalyces of heterotypic cells appear to come into contact. These observations, in conjunction with the results of previous studies, suggest that cell contacts offer a possible pathway for the transmission of inductive stimuli, and that they may be important in the regionalization of the neuralized ectoderm.

Animals↗
PubMed1985

The effect of calcitonin on the prechordal mesoderm, neural plate and neural crest of Xenopus embryos.

Developing Xenopus embryos treated during gastrulation with 22 micrograms/l of salmar calcitonin in the ambient water develop into larvae exhibiting a decrease in interocular distance. In view of the hypocalcaemic properties of calcitonin and the importance of calcium ions in cell aggregation, this phenomenon has been attributed to an alteration in cell adhesion which results in faulty cell migration during gastrulation with consequent abnormalities of the prechordal region of the archenteron roof and the overlying neural plate. Histological examination of affected specimens shows that the principal defect arising from the prechordal mesoderm and prechordal plate is aglossia and a severely reduced oral cavity. This results in narrowing of the head and consequent decrease in interocular distance. Accompanying this effect is distortion of the diencephalon and third ventricle, which may indicate faulty induction of the neural plate by the perturbed subjacent prechordal region.

Animals↗
PubMed1983

Lysosomes and removal of the basal lamina of ameloblasts in early stages of odontogenesis.

Differentiation of ameloblasts is characterised by the development of cytoplasmic organelles and changes in the distal cytoplasm and surface adjacent to the basal lamina. Examination of rat tooth germs prepared for thin section electron microscopy and for freeze fracture, and also stained for acid phosphatase, reveals that three concomitant events occur in this region. The distal surface membrane becomes progressively more undulated, there is an increase in acid phosphatase-containing membrane-bound vesicles (lysosomes) and the basal lamina becomes less apparent and finally disappears. Since the progressive disappearance of the basal lamina is accompanied by an increase in lysosomes, it is possible that lysosomal enzymes are involved in the breakdown of the basal lamina or, alternatively, that the basal lamina is broken down by enzymes derived from odontoblasts, and that its remnants are taken up by the many coated pits and invaginations of the distal surface membrane to be further degraded iun the lysosomal system.

Ameloblasts↗
PubMed1983

Enhancement of contrast in living and fixed specimens by the use of fibre optics.

A method is described which enhances the contrast of living and fixed specimens examined with the stereomicroscope. It consists of immersing the ends of flexible fibre optic light sources together with the specimen in the fluid used for examination. It is reported that not only does this method increase the contrast of living specimens but that it may also be applied to specimens being prepared as thin sections or freeze fracture surfaces for examination with the transmission electron microscope. A further method of enhancement of contrast is suggested which involves the fitting of light filters of complementary colours, one to each of the fibre optic light sources, before immersion with the specimen.

Animals↗
PubMed1983

On the role of the notochord in somite formation and the possible evolutionary significance of the concomitant cell re-orientation.

Homoplastic grafts of re-orientated unsegmented paraxial mesoderm transplanted from stage 20 Xenopus embryos into host embryos of the same age resulted in segmentation and the formation of somites in the same axis as if they had been left in situ. Because grafts transplanted with various orientations came under the stretching effect of the notochord in different directions but never the less maintained their original pattern and direction of segmentation, it would appear that the notochord has no effect on somite formation which thus emerges as an autonomous process independent of the elongation of the embryo. The re-alignment of cells which occurs as the somites are formed and which, in normal unimpeded development, results in the long axis of the cells lying parallel to that of the notochord, is considered in the light of the evolution of sinusoid locomotion and it is suggested that it may be the primary process with the formation of somite blocks as one of its consequences.

Animals↗