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Biomedical subjects

G O'Neill

Publications and source records attributed to G O'Neill.

68 records · Page 4Linked to original sources
PubMed1981

Lipids in forehead vernix from newborn infants.

Neutral lipids in forehead vernix from newborn infants of various gestations were analysed by gas chromatography. Vernix collected from pre-term (less than 37 weeks) infants differed markedly from that collected from near-term (less than or equal to 37 weeks) infants. The principle difference was a increase in the content of squalene relative to other lipids in vernix from near-term infants. This change indicated a surge in fetal sebaceous gland function at about 37 weeks gestation.

Cholesterol↗
PubMed1980

Coronary artery spasm: use of ergonovine in diagnosis.

Ergonovine maleate was administered to 69 patients with chest pain but without significant coronary artery disease (less than 10% luminal diameter obstruction) to determine whether coronary artery spasm could be provoked. Coronary artery spasm was seen at angiography, or inferred from ECG or thallium myocardial perfusion scan changes. The test was positive in 16 patients: all five patients with documented variant angina (Group A); ten of the 19 patients with suspected variant angina (Group B); one of the 11 patients with exercise-induced chest pain (Group C); and none of the 34 patients with atypical chest pain (Group D). Patients with a positive test usually smoked, complained of recurrent nocturnal or early morning chest pain, showed ST changes during spontaneous chest pain and had minot degrees of fixed coronary obstruction (30--70%), when compared to those with a negative test. The only major side effect of the test was transient ventricular tachycardia which occurred in three patients and was reverted by sublingual and parenteral nitroglycerine.

Aged↗
PubMed1979

Pervenous retrieval of embolized catheters from the right heart and pulmonary arteries.

Successful removal of embolized or retained catheter fragments from the right heart was achieved in two out of four patients using pervenous catheter techniques. For the first time a fragment, radiolucent on image intensification, was retrieved from the right pulmonary artery using a wire snare. In a second case a hook-loop was made in the right ventricle with a Judkins left femoral coronary angiographic catheter, which has advantages over previously described hooking devices, to withdraw a fragment to the iliac vein for subsequent snaring. Failure of retrieval occurred only in specially difficult circumstances; when a catheter embolized to the pulmonary artery of a Tetralogy of Fallot, and when in spite of successful ensnarement, a fractured electrode was firmly adherent to the right ventricular apex. Successful pervenous retrieval may require a combination of techniques which move or dislodge, such as a hook or balloon combined with those which ensnare, such as a wire loop or bioptome. Using such techniques, with minimal additions to standard equipment, retrieval procedures can be offered as a routine cardiac catheterization service with a high rate of success.

Cardiac Catheterization↗
PubMed1979

Electrocardiographic changes resembling myocardial ischaemia in asymptomatic men with normal coronary arteriograms.

T wave and ST segment abnormalities in 20 asymptomatic men aged 18 to 55 were investigated because they were identical with myocardial ischaemic changes, and the professional livelihood of the subjects was jeopardised. Coronary arteriograms showed unobstructed arteries in all except one in whom a 50 per cent lesion of the left anterior descending artery was present. Left ventricular angiograms showed a normal contraction pattern, Ejection fractions were normal in 12 and increased in 8. Three characteristic electrocardiographic patterns were observed: flat or inverted T waves in leads II, III, aVF, and V4 to 6 designated type 1; deep T inversion particularly evident in leads V2 to 5 designated type 2, and minor ST segment depression in the inferior and lateral leads without T changes designated type 3. Characteristically, type 1 changes were temporarily suppressed by either beta-blockade or an overnight rest and were more abnormal in the standing position. Type 2 and 3 changes were relatively uninfluenced by these manoeuvres. Maximal treadmill exercise tests were positive in 6 and borderline or negative in 14. When repeated after oxprenolol all tests were negative. Echocardiograms showed asymmetric septal hypertrophy in 3 subjects (ratio of greater than 1.5 between ventricular septum and posterior left ventricular wall). After normalisation by an overnight rest, type 1 T wave abnormalities were reproduced by intravenous adrenaline infusion (0.024 to 0.18 microgram/kg/min) but not by noradrenaline or by adrenaline after prior administration of oxprenolol. When the T waves had remained deeply inverted before infusion despite rest (type 2) adrenaline infusion normalised them and again noradrenaline was without effect. This effect was also prevented by oxprenolol. Type 3 changes were uninfluenced by catecholamine infusion. Plasma catecholamine estimations suggest that catecholamine hypersecretion and hypersensitivity may both be relevant, particularly the latter. The apparent bimodal response of the ventricular myocardium to adrenaline infusion is not surprising since in vitro experiments suggest that reversal of T wave polarity in either direction may result from summation of changes in action potential duration in different parts of the heart. Such changes may be unimodal, that is both areas involved show lengthening or shortening of action potential duration, but by occurring at different rates may lead to a bimodal change in the differences in duration which generate the T wave.

Adolescent↗
PubMedDate not supplied

Burden of care: an important concept for nurses.

Research on family caregiving demonstrates clearly the predominance of women, particularly wives and adult daughters, among the care providers to elderly persons who are frail and chronically ill. It seems that women go to great lengths to care for impaired and elderly relatives, making personal sacrifices, often at great cost to their own health and well-being. Burden of care is a concept emerging in the literature that describes the physical, emotional, social, and financial problems that can be experienced by family caregivers. This concept may be useful to heighten understanding of the family caregiving experience and as such may provide a framework for nursing practice and research. We seek to increase nurses' awareness, through an examination of the burden-of-care literature, of the caregiving experience of women who minister to elderly parents and husbands. We also make a plea for the involvement of nurses with both givers and receivers of care and offer an approach to assessment that incorporates both the meaning and the process of caregiving.

Family↗
PubMedDate not supplied

Prediction of post-operative middle ear pressure changes after general anaesthesia with nitrous oxide.

There has been a growing interest in the changes of pressure which occur in the middle ears of patients undergoing general anaesthesia. In this study the time course of middle ear pressure change was investigated in 38 adult E.N.T. patients scheduled for surgery under general anaesthesia with nitrous oxide. There was found to be a strong correlation between the magnitude of the post-operative middle ear pressure and the theoretical partial pressure of nitrous oxide within the middle ear cleft at the cessation of anaesthesia. The use of the mathematical model developed together with measurements of middle ear pressure taken for several minutes after intubation in any one patient allows prediction of the likely magnitude of the post-operative middle ear pressure change.

Adult↗
PubMedDate not supplied

Computerized analysis of the caloric response.

Caloric responses from 50 consecutive patients, referred routinely for investigation of hearing and/or balance problems, were evaluated by computer and manual methods of analysis. Using measures of nystagmic slow-phase velocity, there was found to be a high degree of correlation between the two methods. Of the 50 patients, the manual method of analysis identified 20 as having abnormal caloric patterns. All of these patients (and an additional 3) were similarly identified by the computer method. The computerized technique was found to be effective, even in the evaluation of irregular signals, making it suitable for use in the clinical situation. Since no decision making on the part of the operator is required, the method described is considered to be a significant advance in computerized methods of analysis of nystagmic slow-phase velocity.

Caloric Tests↗
PubMedDate not supplied

Adult neuronal ceroid lipofuscinosis (Kufs' disease) in two siblings of an Irish family.

The clinico-pathologic features of two siblings with biopsy-proven adult onset neuronal ceroid lipofuscinosis (Kufs' disease) are described. A 38-year-old woman had intractable seizures, delusions and hallucinations followed by ataxia, declining cognitive function and death. At autopsy there was widespread cerebral neuronal accumulation of autofluorescent pigment, in which fingerprint profiles were demonstrated. Systemic involvement was not demonstrated. A 43-year-old brother developed slowly progressive cerebellar ataxia and was found to have similar neuronal autofluorescent pigment on brain biopsy. Nine years later there is gradual cognitive decline and profound ataxia. The salient features of Kufs' disease including cases published since 1988 are reviewed.

Adult↗
PubMedDate not supplied

The caloric stimulus. Temperature generation within the temporal bone.

Temperature measurements were performed on isolated cadaveric temporal bones subjected to caloric irrigation of the external meatus. This was undertaken in an attempt to clarify the pathways of heat transfer involved in thermal stimulation of the temporal bone. On average, the maximum temperature change produced across the lateral semicircular canal was 0.47 degrees C, occurring 74 s after the start of the 30-s irrigation. Temperature changes of approximately 1.5 degrees C were found to occur in the air of the middle ear cleft, indicating significant heat transfer by the process of natural convection. By comparison, removal of the bony ridge joining the external meatus with the inner ear had little effect on the temperature generated across the lateral semicircular canal. It is therefore considered that natural convection within the middle ear cleft plays an important role in caloric stimulation of the vestibular labyrinth. This view is supported by the observation that there is a lack of a direct solid connection between the outer ear and lateral limb of the lateral semicircular canal.

Body Temperature Regulation↗
PubMedDate not supplied

Amino acid residues of 5-lipoxygenase-activating protein critical for the binding of leukotriene biosynthesis inhibitors.

5-Lipoxygenase-activating protein (FLAP) plays an essential role in cellular leukotriene (LT) synthesis and represents the target of three classes of LT biosynthesis inhibitors. We have taken three approaches to localize regions of FLAP involved in the binding of these inhibitors. A comparison of the amino acid sequences of FLAP from eight mammalian species identifies regions of the protein which are highly conserved and consequently may be involved in functional and inhibitor binding properties of the protein. Conversely, amino acids not conserved amongst these species are unlikely to play an essential role in inhibitor binding. Immunoprecipitation of peptide fragments of FLAP cross-linked to photoaffinity analogues of LT biosynthesis inhibitors following site-specific peptide cleavage indicates that the inhibitor attachment site is amino-terminal to 72Trp. Taken together, the cross-species analysis and photoaffinity labelling studies suggest a region within the first hydrophilic loop of FLAP which may be important for inhibitor binding. Site-directed mutagenesis of human FLAP followed by the analysis of FLAP mutants in a radioligand binding assay was used to more accurately define critical amino acid residues within this region. Mutagenesis studies reveal that mutants containing deletions of amino acids in regions of FLAP not conserved between species retain the ability to specifically bind inhibitors. Furthermore, mutants containing deletions in a highly conserved region of the protein (residues 42-61) do not bind inhibitors. These studies have therefore localized specific amino acids of FLAP which are essential for inhibitor binding. The roles that these amino acids play in inhibitor binding and may play in 5-LO activation is under investigation.

5-Lipoxygenase-Activating Proteins↗