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Biomedical subjects

C Healy

Publications and source records attributed to C Healy.

At least 37 records · Page 2Linked to original sources
PubMed1996

Collateral sprouting of cutaneous nerves in man.

Cutaneous nerve collateral sprouting was studied in 20 adults in whom a forearm cutaneous nerve had been resected from the upper arm, such that any recovery of cutaneous nerve function could not be accounted for by nerve regeneration. Ten patients entered the study immediately following surgery and the remainder at intervals thereafter, permitting a longitudinal study covering a 27-month period. Modality-specific stimuli were used to study light touch, sharp pain, cooling, warming and heat pain sensation. Efferent sympathetic C fibre function was determined by measuring sweating in response to total body heating. Though the patients described considerable subjective reduction in the sensory defect within 2 months, by 10-15 months the objective sensory tests showed encroachment at the margin by only 6 mm (P < 0.05) for light touch, 7 mm (P < 0.01) for sharp pain and 11.5 mm (P < 0.001) for heat pain, with no significant change for warming or cooling. By 24 months, recovery of sweating was evident within the zone of persistent sensory loss, for > or = 3 cm beyond the initial light touch margin (P < 0.005). This finding has important clinical implications as it calls into question the reliance placed on the recovery of sweating as evidence of nerve regeneration.

Adolescent↗
PubMed1995

Embryonic expression of the chicken Sox2, Sox3 and Sox11 genes suggests an interactive role in neuronal development.

Three chicken Sox (SRY-like box) genes have been identified that show an interactive pattern of expression in the developing embryonic nervous system. cSox2 and cSox3 code for related proteins and both are predominantly expressed in the immature neural epithelium of the entire CNS of HH stage 10 to 34 embryos. cSox11 is related to cSox2 and cSox3 only by virtue of containing an SRY-like HMG-box sequence but shows extensive homology with Sox-4 at its C-terminus. cSox11 is expressed in the neural epithelium but is transiently upregulated in maturing neurons after they leave the neural epithelium. These patterns of expression suggest that Sox genes play a role in neural development and that the developmental programme from immature to mature neurons may involve switching of Sox gene expression. cSox11 also exhibits a lineage restricted pattern of expression in the peripheral nervous system.

Amino Acid Sequence↗
PubMed1995

Rotation fasciocutaneous flap repair of lower limb defects.

The rotation design was applied to fasciocutaneous flap repair of lower limb defects to produce a functional and aesthetic result superior to that obtained by the transposition design. A prospective, consecutive series of 21 patients is reported, 14 males and 7 females, ranging in age from 17 to 81 years (mean 43 years). The primary defects, 8 traumatic, 12 cutaneous malignancy excisions, and 1 radionecrotic ulcer, ranged in size from 3.5 x 3 cm to 10 x 8 cm (mean 6.6 x 5 cm). The rotation fasciocutaneous flap base ranged from 5 to 25 cm (mean 12 cm), and the radius ranged from 4.5 to 20 cm (mean 9 cm). The inclusion of a back-cut at the flap base permitted direct donor-site closure in all but one patient, obviating the need for a split-thickness skin graft and avoiding the otherwise inevitable significant contour defect. Postoperative bed rest ranged from 3 to 7 days (mean 5 days). Three minor and no major complications occurred, and there was complete survival of all flaps. The results in this series indicate a role for the rotation fasciocutaneous flap in the management of traumatic and excisional defects in the lower limb. It has proved reliable, gives good aesthetic results, and reduces treatment costs.

Adolescent↗
PubMed1994

The clinical technician as a member of the patient-focused healthcare delivery team.

Change is an integral component of hospital operations. The patient care delivery system is not exempt from the forces of change. Ingalls Memorial Hospital has developed the role of the clinical technician to enhance patient-focused care philosophy. This clinical technician program has successfully achieved patient-focused care without physical restructuring; it has increased patient satisfaction, staff satisfaction, continuity, and quality of care.

Allied Health Personnel↗
PubMed1993

LTB4-induced transient neutropenia in the rat: a model for evaluating efficacy and bioavailability of LTB4 receptor antagonists.

An animal model of leukotriene B4- (LTB4) induced neutropenia has been developed to evaluate LTB4 receptor antagonists in vivo. LTB4, a potent chemotactic inflammatory mediator, when administered intravenously, induces a profound, rapid, and transient redistribution of blood neutrophils from the circulating pool to the marginated pool. This phenomenon is applied in the neutropenia model whereby circulating blood neutrophil counts prior to and after intravenous infusion of LTB4 are compared. Kinetics of LTB4-induced neutrophil responses are determined through the use of a Technicon H*1 automated blood cell analyzer. LTB4 receptor antagonists are identified by inhibition of LTB4-induced neutropenia. Standard antiinflammatory compounds including BW-755C, Abbott A-64077 (zileuton), dexamethasone-21-acetate, indomethacin, and naproxen did not affect LTB4-induced neutropenia. A potent LTB4 receptor antagonist, designated "RPR," inhibited LTB4-induced neutropenia following oral administration in a dose-dependent fashion.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1991

Effects of ethinyl estradiol on isoproterenol-induced death in ventricular fibrillation in DOCA-salt pretreated male and female rats.

To assess the effects of ethinyl estradiol on the incidence of death in ventricular fibrillation induced by isoproterenol in DOCA-salt pretreated rats we implanted male and female rats simultaneously with a 20 mg DOCA pellet and pellets containing either ethinyl estradiol or vehicle (wax). Rats drank saline after implantation. After 6 days rats were challenged with a single, sc dose of 150 micrograms of isoproterenol. The average daily dose of estradiol per rat was estimated on the basis of the quantity of pellet lost during 6 days. In male rats the average daily dose of 61.2 +/- 20.2 micrograms/rat of ethinyl estradiol decreased the incidence of mortality by 80%, from 73.3% (11/15) in vehicle treated to 13.3% (2/15) in estradiol treated rats. Death occurred within 19.2 +/- 8.0 minutes from the injection of isoproterenol and was due to ventricular fibrillation. Serum levels of magnesium and potassium were comparable in the two groups both before and after isoproterenol. Isoproterenol induced death in 9 of 11 DOCA-salt pretreated, ovariectomized rats within 22.3 +/- 9.8 minutes. Only 3 of 11 DOCA-salt ovariectomized rats receiving the average daily dose of 28.4 +/- 12.1 micrograms/rat of ethinyl estradiol died. None of 10 ovariectomized untreated rats died from isoproterenol challenge. Serum levels of magnesium and potassium were comparable in the estradiol and vehicle treated groups. The average daily dose of 2.8 +/- 0.42 micrograms/rat of ethinyl estradiol elicited uterine growth but did not influence the incidence of mortality, since 9 out of 16 and 10 out of 16 rats died following isoproterenol in vehicle and estradiol treated DOCA-salt ovariectomized rats. We conclude that only pharmacological doses of estradiol exert protective effects against DOCA-salt induced myocardial sensitization to isoproterenol and that this protection is not associated with relevant changes in serum potassium or magnesium.

Animals↗
PubMed1990

Vastus lateralis myocutaneous flap for reconstruction of defects around the groin and pelvis.

We present our experience using the vastus lateralis myocutaneous flap for the repair of defects around the groin and pelvis. It is a relatively new technique, with many advantages over other flaps used in this area, though it has limitations. The history, anatomy and surgical technique of raising the flap are described and clinical cases are discussed. The importance of patient selection is highlighted.

Adult↗
PubMed1990

The versatility of the lateral arm flap.

We present our experience of a personal series of 17 lateral arm flaps in a variety of forms and clinical situations. The anatomy of the flap is briefly reviewed in relation to the operative findings, and the advantages and disadvantages of the flap are discussed.

Adult↗
PubMed1990

Focusable Doppler ultrasound in mapping dorsal hand flaps.

The dorsal arterial anatomy of 50 normal hands was mapped using high frequency pulsed wave Doppler ultrasound. The findings correlated with previous anatomical studies regarding the variability in the incidence of the arteries. Eight clinical cases were studied preoperatively, seven of whom underwent surgery involving local flaps. Intraoperatively the presence of the mapped vessels was confirmed in each case. This investigation defines the role of high frequency pulsed wave Doppler ultrasound in the mapping of dorsal hand flaps.

Adult↗
PubMed1990

Magnetic resonance imaging of the carpal tunnel.

Eleven wrists in eight patients with carpal tunnel syndrome were investigated by electrophysiological studies and magnetic resonance imaging (M.R.I.). The operative findings in ten wrists correlated with the M.R.I. evidence of synovial disease, carpal tunnel stenosis and median nerve compression.

Adult↗
PubMed1988

Effects of low-dose aspirin on endogenous eicosanoid formation in normal and atherosclerotic men.

We have investigated the effects of a low-dose aspirin regimen (120 mg orally, then 20 mg twice daily) on the in vivo synthesis of prostacyclin, thromboxane and prostaglandin E in man by measurement of their urinary metabolites (PGI2-M, TxB2-M, PGE-M) using gas chromatography-mass spectrometry. A comparison was made between the selectivity of low-dose aspirin for thromboxane vs prostacyclin synthesis in patients with atherosclerosis, age-matched controls without vascular disease, and young healthy volunteers. After one week of treatment, aspirin reduced TxB2-M synthesis to a similar extent in the three groups (mean declines of 86, 84 and 78% respectively), while there was an unexpected difference in effect on PGI2-M, with only a 27% fall in the young volunteers but 53% and 54% declines in the patients with vascular disease and their age-matched controls. Serum TxB2 was reduced greater than 98% in all groups while PGE-M excretion was unchanged. These results indicate that bioselectivity for inhibition of Tx synthesis by aspirin is more difficult to achieve in older subjects than in the young volunteers previously studied and that very low, frequent dosing, or a sustained-release preparation of aspirin would be needed to achieve bioselectivity for Tx inhibition in patients with vascular disease.

Adult↗
PubMed1987

Thromboxane A2 biosynthesis in human disease.

Thromboxane A2 (TxA2), the predominant cyclooxygenase product of human platelets, is a potent vasoconstrictor and platelet agonist. Although its biological properties are readily appreciable in vitro, it has been difficult to define its biological importance in vivo. To a large extent this reflected the problems associated with efforts to monitor biosynthesis of this eicosanoid and the lack of selective pharmacological probes that prevented the synthesis of TxA2 or antagonized its biological action in vivo. Recently the analysis of urinary metabolites of TxB2 has become simplified so that the methodology is readily applicable to clinical studies. This provides a noninvasive, time-integrated index of Tx biosynthesis. Although one cannot definitively establish a tissue of origin for metabolites measured in urine, indirect evidence suggests that urinary TxB2 derives primarily from the kidney whereas its dinor metabolite predominantly reflects platelet biosynthesis under physiological conditions. Although plasma concentrations of TxB2 are readily confounded by platelet activation ex vivo, the enzymatic metabolites formed from TxB2 have recently been identified and appear to bypass this problem. Combined analysis of long-lived (e.g., 11-dehydro-TxB2) and short-lived (e.g., 2,3-dinor-TxB2) metabolites in plasma promise to more accurately localize phasic increases in the biosynthesis of TxA2 and have been paralleled by the development of antagonists of the TxA2/prostaglandin endoperoxide receptor and their study of humans. The use of such specific probes in conditions characterized by abnormal biosynthesis of TxA2 promises to define the biological role of this mediator for humans.

Arachidonic Acid↗
PubMed1985

Ventricular fibrillation and the Brattleboro rat.

Despite considerable evidence from both clinical and animal experiments, the role of beta-adrenergic stimulation in the development of life-threatening cardiac arrhythmias is not well understood. Recent studies indicate that the posterior pituitary hormone, arginine vasopressin, may have a modulatory effect on cardiovascular sympathetic tone, especially with respect to blood pressure and heart rate. Employing the homozygous Brattleboro rat, an animal genetically deficient in the synthesis of arginine vasopressin, the following report offers evidence that the neuropeptide may also act on central pathways to suppress arrhythmogenic activity elicited by beta-adrenoceptor stimulation.

Animals↗
PubMed1985

DOCA-salt induced myocardial sensitization to ventricular fibrillation by isoprenaline in rats. Role of the autonomic nervous system.

The possible role of the autonomic nervous system in the development of myocardial sensitization to isoprenaline produced by DOCA-salt pretreatment was evaluated in bilaterally unanaesthetized rats subject to chronic ganglionic blockade with chlorisondamine or hexamethonium and to treatment with 6-hydroxydopamine. Isoprenaline produced ventricular fibrillation and death in rats pretreated for 6 days with DOCA (20 mg pellet, s.c.) and 0.9% saline. The incidence of mortality was dose dependent and was 76.6% with 150 microgram/kg of isoprenaline. Adrenalectomy did not alter the mortality rate. The combination of adrenalectomy with concurrent chronic ganglionic blockade significantly decreased the incidence of mortality and delayed the time of death. In contrast, 6-hydroxydopamine treatment and adrenalectomy did not alter the incidence of mortality nor time of death. No differences in myocardial noradrenaline turnover were detected in rats susceptible and nonsusceptible to death in ventricular fibrillation. We conclude that myocardial sensitization to isoprenaline induced by DOCA-salt requires a neurogenic component, which is not, however, manifested by changes in myocardial noradrenaline turnover.

Adrenalectomy↗