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Biomedical subjects

P Fleming

Publications and source records attributed to P Fleming.

At least 109 records · Page 6Linked to original sources

A second Australian family with hemoglobin North Shore (beta 134 Val----Glu).

A second Australian family is reported with Hemoglobin North Shore (beta 134 Val----Glu), an unstable hemoglobin, causing no clinical symptoms. All affected family members showed only mild reticulocytosis and microcytosis on the blood film, despite the strongly positive isopropanol test for Hb (hemoglobin) stability and numerous red cell inclusions. Hb North Shore constituted 31-38% of the total hemoglobin and migrated on the anodal side of Hb A at pH 8.9. The association of a mildly raised Hb A2 level and thalassemic phenotype with Hb North Shore previously reported, is confirmed in this study.

Adult↗

Pseudosickling of hemoglobin Setif.

Hemoglobin Setif produces pseudosickling of red cells in vitro; the nature of the process and the conditions that "trigger" it are unknown. Studies of red cells, hemolysates, purified hemoglobin solutions, and artificial mixtures of Hb A and Setif suggest that pseudosickling is produced by intracellular crystallization of insoluble hemoglobin. Increased tonicity of the suspending medium accentuates the process, probably by causing a rise in intracellular hemoglobin concentration. If precipitates from A/Setif mixtures are analyzed, they always contain Hb A, suggesting an unusual mechanism for the process. Despite the fact that osmolality in the renal medulla is similar to that which produces pseudosickling in vitro, carriers do not have renal dysfunction of the type found in patients with sickle cell disease.

Adult↗

Contrasting monoamine oxidase activity and tyramine induced catecholamine release in PC12 and chromaffin cells.

PC12 (phaeochromocytoma derived) cells possess the catecholamine synthesizing enzymes as well as the ability to store and release the catecholamines in response to K+. However, their monoamine oxidase activity and catecholamine release in response to tyramine has not been examined previously. PC12 cells have monoamine oxidase activity which oxidizes type A (noradrenaline and serotonin) and type A-B (dopamine, tyramine and kynuramine) substrates, and is selectively inhibited by clorgyline (IC50 approximately 10(-6) M). In contrast, PC12 cell monoamine oxidase hardly oxidizes phenylethylamine a type B substrate, and is relatively insensitive to inhibition by the selective monoamine oxidase type B inhibitor, 1-deprenyl (IC50 approximately 10(-6) M). By the above criteria it is apparent that the monoamine oxidase in PC12 is solely type A. The kinetics of the oxidase are similar to those of monoamine oxidase type A reported in other tissues including the adrenergic neuron, having apparent Km values of 400, 280, 170 and 227 microM for noradrenaline, dopamine, serotonin and tyramine. The apparent Km value for phenylethylamine is 235 microM. On the other hand, isolated chromaffin cells have the B form of monoamine oxidase with high affinity (Km approximately 25 microM) for phenylethylamine and low affinities for noradrenaline (Km approximately 1100 microM) and adrenaline (Km approximately 1700 microM). This enzyme form is selectively inactivated by the monoamine oxidase type B inhibitor, 1-deprenyl. In similar fashion to peripheral adrenergic neurons, PC12 cells share the capacity to express a tyramine releasable pool of catecholamines, a property entirely lacking in mature cultured chromaffin cells, even though the latter cells are capable of taking up tyramine by a cocaine sensitive process.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗

Tissue expansion: its role in traumatic below-knee amputations.

A case of nonhealing ulcer overlying a traumatic below-knee amputation treated with tissue expansion, excision, and primary closure is presented. Histologic evidence of tissue injury following tissue expansion is presented, and a recommendation for its cautious use in patients with impaired wound healing is suggested.

Adult↗

Pseudomonas cepacia infection in cystic fibrosis: an emerging problem.

The prevalence of Pseudomonas cepacia infection increased from 10% in 1971 to 18% by 1981 in a population of approximately 500 patients with cystic fibrosis. Carriage of P. aeruginosa has remained unchanged at 70% to 80% over the same period. Patients infected with P. cepacia have greater impairment of pulmonary function than those with P. aeruginosa. A syndrome characterized by high fever, severe progressive respiratory failure, leukocytosis, and elevated erythrocyte sedimentation rate has occurred in eight patients over the past 3 years, with a 62% fatality rate. Because P. cepacia strains are uniformly resistant to ticarcillin, piperacillin, and aminoglycosides, and because ceftazidime is ineffective despite in vitro activity, treatment of these infections is very difficult. Prevention of acquisition and effective treatment of P. cepacia in patients with cystic fibrosis are now major clinical problems in our clinic.

Adolescent↗

Hemoglobin Setif and in vitro pseudosickling noted in a family with co-existent alpha and beta thalassemia.

A Turkish Cypriot family was investigated for suspected heterozygous sickle cell disease, which had been reported in a maternal branch of the family resident in England. Two maternal grandparents were of African Negro origin. Pseudosickling was noted in members of the family who were found to have an abnormal hemoglobin fraction. This abnormal fraction proved to be Hemoglobin Setif (alpha 94 Asp leads to Tyr). Family studies demonstrated the presence of this hemoglobin in varying proportions in the mother and 2 of the 4 children. alpha and beta thalassemia traits are also present in several family members.

Adolescent↗

Pilot study on use of PMPs.

Patient management problems (PMPs) have been used for many years in an attempt to design tests capable of measuring clinical problem-solving ability. Problems have arisen particularly related to criterion validity, though some studies have suggested that content and construct validity are satisfactory. One of the major problems has been that a common definition of problem-solving ability has not been developed yet. In addition, various formats have been used with considerable variety in construction, possibly influencing outcomes, and scoring procedures have not been standardized. A serious charge has been that PMPs are content specific and therefore are unreliable and not valid for measuring any general characteristic such as problem-solving ability (assuming this exists).

Australia↗

Memory decline in the aged: treatment with lecithin and physostigmine.

Normal aged subjects were given lecithin and placebo for 5 weeks each in a double-blind crossover study. Supraspan tests of memory and learning failed to show any significant changes as a result of these treatments. Addition of a single IV infusion of physostigmine did not improve performance. These findings neither support nor weaken the "cholinergic hypothesis" of cognitive impairment in aging and dementia, but they imply that simple cholinergic hypofunction is unlikely.

Acetylcholine↗

Nonimmunologic fetal hydrops wtih theca lutein cysts.

A case of nonimmunologic fetal hydrops complicated by bilateral theca lutein cysts is presented. It is thought that the theca lutein cysts were caused by elevated human chorionic gonadotrophin levels that were a result of fetal hydrops. These cysts should not be treated with surgery, since they usually regress once the pregnancy ends.

Adult↗