Biomedical subjects

D O'Hare

Publications and source records attributed to D O'Hare.

At least 19 recordsLinked to original sources

PubMed1995

Dye laser treatment of port-wine stains: comparison of the continuous-wave dye laser with a robotized scanning device and the pulsed dye laser.

BACKGROUND: Despite good results in the treatment of most port-wine stains (PWS) with continuous-wave visible-light lasers, light PWS and those in certain locations respond less favorably and have a higher risk of scarring. Robotized scanning devices such as the Hexascan device have been developed for continuous-wave laser sources to produce greater target specificity, to increase reproducibility of results, and to decrease the incidence of adverse effects. OBJECTIVE: The purpose of this study was to compare the effects of the same wavelength of light (585 nm) on test sites within PWS with the flashlamp-pumped pulsed dye laser and a continuous-wave tunable dye laser scanned through a Hexascan robotized scanning device. METHODS: Two adjacent, noncontiguous sites within PWS were treated in 29 patients, one site with the flashlamp-pumped pulsed dye laser and the other with an argon-pumped continuous-wave tunable dye laser affixed to a Hexascan device. RESULTS: Twenty-eight patients completed the study. The pulsed dye laser was found to be superior to the continuous-wave dye laser with the Hexascan device in 45% of patients, whereas the continuous-wave tunable dye laser with the Hexascan device was considered superior in 15%. There was no difference in the remaining 40%. Undesirable side effects were infrequent with both treatments. There was no significant difference in hypopigmentation or atrophic and hypertrophic scarring, but hyperpigmentation was more frequent with the continuous-wave dye laser with the Hexascan device. CONCLUSION: Both the pulsed dye laser and continuous tunable-wave dye laser with the Hexascan device produce slight lightening after one treatment. The pulsed dye laser produces slightly greater lightening than the continuous-wave tunable dye laser with the Hexascan device 6 weeks after treatment of test areas within PWS in 40% of those treated. It also produced slightly less hypopigmentation and hyperpigmentation.

Adolescent↗

PubMed1995

Hepatotoxicity and transaminase measurement during isoniazid chemoprophylaxis in children.

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Adolescent↗

PubMed1995

Cardiac hypertrophy impairs recovery from ischaemia because there is a reduced reactive hyperaemic response.

OBJECTIVE: The aim was to investigate whether impaired coronary flow reserve associated with cardiac hypertrophy could significantly limit the flow debt repayment following short periods of coronary occlusion and exacerbate or prolong episodes of myocardial ischaemia. METHODS: Left ventricular hypertrophy was induced in guinea pigs by aortic constriction and the hearts were isolated six weeks later for Langendorff perfusion. Sham operated animals served as controls. The reactive hyperaemic response was studied following various lengths of occlusion of flow and the extent of aerobic and anaerobic metabolism was assessed in each group. RESULTS: Heart weight/body weight ratio was increased by approximately 25% (P < 0.001) with aortic constriction. The reactive hyperaemic flow response in isolated hearts was impaired by hypertrophy in both magnitude (P < 0.05) and duration. The repayment of flow debt was also significantly reduced, suggesting an inadequate recovery of the myocardium following the occlusion. The total amount of O2 consumed by the heart throughout the duration of hyperaemia was less in hypertrophy than in sham operated controls, suggesting a decrease in aerobic metabolism. Total lactate discharge expressed as a ratio of O2 consumed, which provides an estimation of the degree of anaerobic in relation to aerobic metabolism, was greater in hypertrophy than in sham operated controls. CONCLUSIONS: The hypertrophied heart is more vulnerable to brief periods of ischaemia because of an impaired reactive hyperaemic response which results in delayed metabolic recovery. These abnormalities may contribute to the increased morbidity associated with cardiac hypertrophy.

Animals↗

PubMed1991

Electrochemical method for direct measurement of oxygen concentration and diffusivity in the intervertebral disc: electrochemical characterization and tissue-sensor interactions.

A method was developed for the in vivo measurement of oxygen concentration and diffusivity in the intervertebral disc using a bare gold cathode. The effects of surface adsorption were quantified using electrochemical methods and it was demonstrated that valid data can be obtained despite interactions between the electrode and the macromolecules of the intervertebral disc. The technique is used to show the dependence of the oxygen transport properties on tissue water content.

Adsorption↗

PubMed1991

Tuberculosis in children 10 years of age and younger: three decades of experience during the chemotherapeutic era.

The 863 patients, aged 10 years and younger, treated at the Children's Chest Clinic of Bellevue Hospital during three decades (1953 through 1981) clearly indicated the success of antituberculosis therapy. There were no deaths from tuberculosis. Early treatment is associated with a reduction in the serious forms of disease, eg, meningitis, miliary disease, and bone infections, and with preventing death. Medication was well tolerated: only 1.1% of the patients had adverse reactions, all of which were reversible. Consistent compliance with medication of only 62% of patients is a challenge to the medical profession. Only 22.5% of mycobacterial cultures were positive. Long-term follow-up of patients was rewarding: seven pregnancies with healthy mothers and babies, and no reactivation of tuberculosis by later infections, even those such as measles or pneumonia. The severity of disease was related largely to patient's age (3 years and younger) and intimacy of contact, the highest rate being when the mother was the contact. The long-term experiences emphasizes the value of early identification, therapeutic compliance, and comprehensive contact, tracing in the future elimination of tuberculosis. Prophylactic therapy and close observation should be considered for contacts, especially those exposed to human immunodeficiency virus infections and addicted to drugs.

Antitubercular Agents↗

PubMed1991

A survey of community (out-of-hospital) sites used in pediatric training.

A survey was completed of US pediatric residency programs about the use of community sites in training. A total of 85% of program directors responded and reported a wide use of the 21 identified survey sites. Further study is needed to determine the appropriate contribution that community sites can make to pediatric training.

Internship and Residency↗

PubMed1990

Pilots' perception of risks and hazards in general aviation.

A sample of licensed pilots completed the Aeronautical Risk Judgment Questionnaire (ARJQ) which was developed to obtain data on pilots' perceptions of their abilities, willingness to take risks, hazard awareness, and judgments of the risks of general aviation. A subset of these subjects was tested on a computerised test of flight decision-making involving a proposed VFR flight in marginal weather conditions. Results from the ARJQ indicate relatively low levels of risk and hazard awareness combined with a generally optimistic self-appraisal of abilities by this sample of general aviation pilots. Younger subjects (under 30) were found to rate the likelihood of being involved in an accident more highly than did older pilots. Experienced pilots obtained higher scores on a measure of "personal invulnerability" from factors commonly associated with accidents. This does not appear to be due simply to overconfidence in their abilities, since it was the younger and less experienced pilots who held the most unrealistically optimistic appraisals of their ability. Pilots who proceeded with the computerised flight rate themselves as having a greater willingness to take risks, and were likely to be younger and have higher total hours than those who rejected the flight. They were also found to have significantly higher scores on the measure of "personal invulnerability." The results are discussed in relation to previous epidemiological findings and possible safety prevention strategies.

Accidents, Aviation↗

PubMed1985

Congenital tuberculosis. Review and diagnostic guidelines.

A review of congenital tuberculosis was prompted by the successful treatment of this disease in a unique patient. She was followed up for 27 years, and gave birth to two normal, uninfected newborns despite calcifications throughout her abdomen and elsewhere. Tuberculosis of the newborn, whether acquired congenitally or postnatally, is preventable. Recommendations for diagnosis of congenital tuberculosis are given. Determination of the mother's tuberculin status or suitable testing should be done early in pregnancy. Endometritis is cited as an unrecognized source of fetal infection.

Abdomen↗

PubMed1983