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Biomedical subjects

R X Murphy

Publications and source records attributed to R X Murphy.

26 records · Page 2Linked to original sources

Delayed debulking of free muscle flaps for aesthetic contouring debulking of free muscle flaps.

Although denervated muscle and myocutaneous free flaps atrophy over a period of time, when used for surface coverage they may remain bulky, resulting in a less than optimal aesthetic result. With the availability of a number of donor sites, soft tissue defects can often be reconstructed with like tissue in a single stage. Even though the goal of all plastic surgeons is to achieve a good cosmetic result, special circumstances might dictate that need take precedence over form. We have had six cases where a bulky muscle was used to achieve well vascularised coverage. After wound closure had been successfully accomplished, a secondary debulking procedure was performed safely for a final acceptable aesthetic result.

Adolescent↗

Amputation stump salvage using a "banked" free-tissue transfer.

A free radical forearm flap was salvaged from a nonreplantable amputated extremity and banked on the ipsilateral chest wall. Later, the flap was simply rotated to provide coverage of the proximal humeral stump, eliminating the need for a second microvascular procedure.

Adult↗

Yield of screening urography in young women with urinary tract infection.

In order to determine the diagnostic yield and therapeutic outcome of screening urography in young women with urinary tract infection, 1000 urographic examinations were reviewed. Of these 96.4% were normal; 1.4% revealed abnormalities that subsequently required therapy. Each treated abnormality was expensive to diagnose; protocols other than universal urography could have made most of these diagnoses. The incidence of treated abnormalities may be no greater in this group than in the general population. Universal screening urography in these patients cannot be definitely recommended.

Adolescent↗

Tissue distribution of soluble contrast: effect of dose variation and changes with time.

The changes in density of specific tissues after administration of intravenous contrast agents is easily detectable by computed tomography and is important in distinguishing normal and pathologic tissues. The time course of these density changes was determined in nine specific tissues in the rat by measuring tissue radioactivity after intravenous administration of 125I iothalamate. The effect of dose variations and the distribution of contrast between the extravascular and intravascular spaces in each tissue were studied as well. Most tissues showed a peak in contrast concentration immediately after injection and displayed a steady fall in concentration thereafter. In most tissues, the concentration was directly proportional to the administered dose. In liver and kidney, however, there was a relative delay in peak concentrations; concentrations were not directly proportional to the two administered doses and presumably reflected active accumulation. In all tissues, most of the contrast material was in the extravascular rather than the intravascular space within 1 min after administration; the ratio of contrast in the extravascular space to the total amount of contrast in each tissue rose steadily thereafter. These observations reveal significant differences among tissues in the distribution of contrast agents, which should be useful in the planning of CT protocols.

Animals↗

Noninvasive estimation of pulmonary arterial pressure by analysis of pulmonary blood-flow distribution.

To determine whether a correlation exists between pulmonary arterial (PA) pressure (Pa) and the distribution of pulmonary blood flow, this distribution was measured in four upright dogs in the control state and during intravenous infusions of epinephrine or prostaglandin F2 alpha. During suspension of respiration, 15 mCi of Xe-133 were injected intravenously, and perfusion and equilibration lung images were recorded with a scintillation camera. The procedure was performed several times on each dog, with and without pharmacological elevation of PA pressure by 5 to 50 cm H2O. For each scintigram, the relative blood flow per unit ventilated lung volume (F) was plotted against centimeters above the hilum (h). Pulmonary arterial pressure was derived from each curve, assuming the relation F = B(Pa - hD)2, where B = constant and D = specific gravity of blood. Calculated PA pressure correlated strongly (r = 0.83) with measured PA pressure, suggesting a possible means of noninvasive estimation of PA pressure.

Animals↗

Female mouse maturation: effects of excreted and bladder urine from juvenile and adult males.

A sequence of 4 experiments examined the effects of prepubertal and adult males on the sexual maturation of young female house mice. The results support 3 conclusions: (1) the presence of a prepubertal male or of urine from prepubertal males does not affect the timing of sexual maturation in young female house mice; (2) the maturation-accelerating pheromone produced by adult males is present in the bladder urine of intact adult males but is absent from both excreted and bladder urine of castrated males; and (3) young females caged with 7 prepubertal males or with a castrated adult male mature earlier than control females caged alone. Results indicating that the presence of a castrated male leads to earlier sexual maturation of young female mice differ from previous findings. A possible explanation for this contradictory result is based on the ability of young weanling female mice to acclimatize the thermoregulate when separated from the dam and litter-mates. A model for density-feedback population regulation in house mice involving pheromones produced by males and females is presented.

Age Factors↗