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Biomedical subjects

P McGrath

Publications and source records attributed to P McGrath.

At least 19 recordsLinked to original sources
PubMed1995

Exercise stimulus increases ventilation from maximal to supramaximal intensity.

This study investigated the influence of an exercise stimulus on pulmonary ventilation (VE) during severe levels of exercise in a group of ten athletes. The altered ventilation was assessed in relation to its effect on blood gas status, in particular to the incidence and severity of exercise induced hypoxaemia. Direct measurements of arterial blood were made at rest and during the last 15 s of two intense periods of cycling; once at an intensity found to elicit maximal oxygen uptake (VO2max; MAX) and once at an intensity established to require 115% of VO2max (SMAX). Oxygen uptake (VO2) and ventilatory markers were continually recorded during the exercise and respiratory flow-volume loops were measured at rest and during the final 30 s of each minute for both exercise intensities. When compared to MAX exercise, the subjects had higher ventilation and partial pressure of arterial oxygen (PaO2) during the SMAX intensity. Regression analysis for both conditions indicated the levels of PaO2 and oxygen saturation of arterial blood (SaO2) were positively correlated with relative levels of ventilation during exercise. It was apparent that mechanical constraints to ventilate further were not present during the MAX test since the subjects were able to elevate VE during SMAX and attenuate the level of hypoxaemia. This was also confirmed by analysis of the flow volume recordings. These data support the conclusions firstly, that overwhelming mechanical constraints on VE were not present during the MAX exercise, secondly, the subjects exhibiting the most severe hypoxaemia had no consistent relationship with any measure of expiratory flow limitation, and thirdly, ventilatory patterns during intense exercise are strong predictors of blood gas status.

Adolescent↗
PubMed1995

It's ok to say no! A discussion of ethical issues arising from informed consent to chemotherapy.

This article is written in response to anecdotal evidence from patients, reports from nurses, sociological studies, and documentation from oncologists, which all suggest that the process of refusing treatment for chemotherapy is not an easy one. There is substantial evidence to suggest that pressures that are counterproductive to informed consent are having an impact on the decision making of vulnerable individuals coping with the stress of terminal illness through cancer. Informed consent is a basic ethical principle underpinning any medical or nursing intervention (Johnstone M. Bioethics: a nursing perspective. Sydney: Harcourt Brace Jovanovich, 1989). The following focus on informed consent is an attempt to begin to address the present hiatus which exists in the health literature on ethical issues surrounding the modality, chemotherapy (Young D. An ethical approach to chemotherapy in private practice. J Natl Cancer Inst 1992;84:810). Recent research suggests that the holistic orientation of nurses, in comparison to the reductionist stance of physicians, allows them to be emotionally close to their patients and hence, more aware of the difficulties individuals experience in coping with stressful regimens (Uden G, Norberg A, Lindseth A, Marhaug V. Ethical reasoning in nurses' and physicians' stories about care episodes. J Adv Nurs 1992;17:1028-34). Consequently, it is anticipated that ethical issues in relation to chemotherapy, a modality that has been described as distressing and capable of seriously compromising quality of life (Burish T, Tope D. Psychological techniques for controlling the adverse side effects of cancer chemotherapy: findings from a decade of research. J Pain Sympt Man 1992;7:287-301), will have an impact on the working life of many oncology nurses.

Antineoplastic Agents↗
PubMed1994

Medical-surgical nurses' utilization of research methods and products.

The purpose of this study was: (a) to describe the self-reported use of the methods and products of research by medical-surgical nurses, and (b) to identify attitudes toward the use of research-based knowledge in clinical nursing practice. Two hundred and twelve registered nurses completed the Research Utilization Questionnaire. Survey results indicated that it was difficult for respondents to change practice based on research. Nurses were willing to participate in research if investigations were relevant to practice. Articles from nursing research journals were ranked low by the respondents as sources of knowledge, while information gained from individual patients was ranked high.

Attitude of Health Personnel↗
PubMed1994

Mothers of children with chronic conditions: supportive and stressful interactions with partners and professionals regarding caregiving burdens.

Ninety mothers appraised the specific sources and types of social support they received in relation to specific types of demands of caring for a child with a chronic condition. Qualitative data were collected during home interviews with the mothers of children with diabetes, spina bifida, or cystic fibrosis. Virtually all of the mothers described primary caregiver demands that were directly related to the child's condition, such as physical care, health care in illness situations, and the child's psychological and social development. Many mothers also reported secondary demands related to their own needs, family roles and relationships, and the mother's activities outside the home. Mothers experienced gaps in the support provided for specific caregiving burdens and encountered stressful interactions with their partners and health professionals in particular.

Adolescent↗
PubMed1992

Accuracy of pulse oximetry during exercise stress testing.

Pulse oximetry is used extensively during exercise stress-testing in the clinical and sports medicine settings. There are few validation studies to assess the appropriateness of using pulse oximetry under conditions of potentially compromised peripheral blood flow. To study the accuracy of pulse oximetry during severe exercise stress, 10 athletes undertook 3 bouts of exhaustive exercise; once at an intensity requiring VO2max (max), once at 115% of VO2max (Smax), and once at Smax while FIO2 was increased to 0.30. The results indicate relatively large underestimations occur when pulse oximetry is used to estimate %SaO2 during exercise, when compared to the criterion samples of gas analysis in arterial blood. These differences were exacerbated as the exercise intensity increased from a mean(+/- SE) difference of 2.9 +/- 0.7 %SaO2 at max to 4.6 +/- 0.7 %SaO2 at Smax. Breathing a higher FIO2 reversed the hypoxemia that occurred during the normoxic exercise, however, pulse oximetry measurements failed to detect this alteration in %SaO2. Estimates of oxygen saturation during severe exercise using pulse oximetry should be viewed with caution, as potentially large errors may occur.

Adolescent↗
PubMed1992

Recurrent laryngeal nerve and the posterior fascial attachment of the thyroid gland.

An investigation based on dissection of cadaveric specimens was undertaken to obtain additional data on the relationships between the recurrent laryngeal nerve and the posterior fascial attachment of the thyroid gland. Ninety-four dissections were selected for detailed study. The posterior fascial attachment on each side was found to form two bands--a vertical band described previously and a horizontal band. The horizontal band was found to be present in all cases and to be constant in position. The posterior edge of the horizontal band followed posteriorly leads to the recurrent laryngeal nerve. The nerve always had a close relationship to the horizontal band and was often adherent to it. It is suggested that the use of the horizontal band to locate the recurrent laryngeal nerve would be of particular value when the inferior thyroid artery is absent, when the nerve is non-recurrent on the right side, or when there is distortion of the normal anatomy.

Aged↗
PubMed1992

The proboscis in human cyclopia: an anatomical study in two dimensions.

A 2-dimensional anatomical study has been undertaken of the proboscis and its contribution to the roof of the median orbit in human cyclopia. The cyclops material consists of 4 sectioned fetal heads and a dried cyclops skull. The skeleton of the proboscis is formed by the nasal capsule. The base of the proboscis lies in the floor of the anterior cranial fossa filling an extended ethmoidal notch and contributing to the roof of the median orbit anterior to the fused lesser wings of sphenoid. The cavity of the proboscis is lined with squamous epithelium, respiratory and olfactory mucosa. Olfactory fibres pass from the proboscis into the extradural space of the ethmoidal notch forming a collection of tissue similar to the inferior layer of the normal olfactory bulb. The data indicate that the proboscis represents the anterosuperior part of the normal nasal cavity developed in the absence of median components. It is suggested that the cyclops face constitutes a model for the study of the development of the normal face.

Eye Abnormalities↗
PubMed1991

Prognostic significance of proliferation associated nucleolar antigen P120 in human breast carcinoma.

Nucleolar antigen P120 is detected in rapidly proliferating cells but not in normal resting cells or in many benign and slowly growing malignant tumors. The objective of the study was to determine whether the expression of P120 in breast cancer correlated with histopathological or biological properties associated with prognosis. In this retrospective study, 120 primary breast tumors were analyzed for P120; 114 of these tumors were also stained for the erbB-2 protein. Immunopositive staining was correlated with patient survival, nodal status, estrogen receptor levels, and number of mitoses. Sixty-nine % (83 of 120) of the tumors were positive for P120; 25% (28 of 114) stained positively for erbB-2. Of the 28 erbB-2 positive tumors 26 were also positive for the P120 protein. Forty-six % (55 of 120) of the specimens were from patients who later died from recurrent breast cancer; P120 was detected in 89% (49 of 55) of these specimens. In 52% of the survivors the P120 protein was also expressed. P120 negative tumors were highly correlative with survival (P = 0.0001); 84% (32 of 37) of patients with P120 negative tumors survived more than 7 years without evidence of recurrent disease. Multivariate analysis showed that the worst prognosis was for patients who had tumor positive nodes and expressed P120 (P = 0.0001); death occurred in 73% (30 of 41) of these patients. For the node negative patients who did not express P120, 5-year survival was 90% (19 of 21 patients); 5-year survival for the node negative patients who expressed P120 was significantly less (67%; 28 of 42 patients). Patients with P120 negative tumors had a good prognosis, irrespective of their nodal status. In this group, survival of node negative patients was 86% (18 of 21) and for those with positive nodes survival was 82% (13 of 16). A poor prognosis was found for patients with intense erbB-2 stained tumors (5 of 7 patients died). Weak staining of erbB-2 tumors (21 specimens) was not correlated with patient survival. Compared to P120 negative tumors, P120 positive tumors had greater numbers of mitoses (9.06 versus 6.65) and an almost 2-fold increase in the occurrence of positive nodes (one of every 4.67 versus one of every 8.81). The number of P120 positive tumors was greater in estrogen receptor positive tumors (75%) than in estrogen negative tumors (54%).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1990

Cerebral laterality and depression: relations of perceptual asymmetry to outcome of treatment with tricyclic antidepressants.

The relationship of cerebral laterality to outcome of treatment with antidepressants was examined by comparing perceptual asymmetry in subgroups of depressed patients formed on the basis of clinical response to a tricyclic antidepressant (TCA) or a monoamine oxidase inhibitor (MAOI). Perceptual asymmetries of 63 unmedicated depressed patients were assessed for verbal and nonverbal tasks, using dichotic listening and visual half-field methods, and retests were obtained on 49 patients after about 6 weeks of treatment. There were significant differences between TCA responders and TCA nonresponders in dichotic listening and visual field asymmetries. Differences in perceptual asymmetry were specific to TCAs, in that no comparable differences existed between MAOI responders and MAOI nonresponders. Although perceptual accuracy improved following successful TCA treatment, abnormal perceptual asymmetries in TCA responders were present before and after treatment and may thereby represent state-independent characteristics.

Adult↗
PubMed1990

Floor of the median orbit in human cyclopia: an anatomical study in three dimensions.

A three dimensional study has been undertaken of the floor of the median orbit in human cyclopia. The cyclopic material consists of a full term desiccated head, a dried fetal skull and four sectioned fetal heads. Most elements in the floor of the median orbit are normal. Such abnormalities as are present in the bony floor and the related lacrimal sac are considered to be secondary to the absence of the presphenoid and the postero-inferior part of the nasal cavity. The abnormalities seen in the medial and inferior rectus muscles are considered to be secondary to the absence of a medial orbital wall and normally defined and directed optic nerves and eyeballs.

Eye Abnormalities↗
PubMed1989

"Challenges in pain management". Part 4. Teaching coping strategies to adolescents with migraine.

A treatment program was developed involving cognitive and behavioral strategies for the treatment of migraine headaches with adolescents at the Children's Hospital of Eastern Ontario. These techniques include: a headache diary, progressive relaxation techniques, cognitive restructuring, distraction or attention focusing, mental activities, thought stopping, imagery, behavior rehearsal, assertiveness and problem solving. The article details the therapeutic use of these techniques. An analysis of each strategy is presented in three sections: a rationale to the adolescent, recommendations to the therapist and a troubleshooting section.

Adaptation, Psychological↗
PubMed1989

Palatine bone in human cyclopia.

In human cyclopia, a maxillopalatine mass separates the median orbit from the oral cavity. The palatine component of this bony mass has been studied in serial sections through the median third of the head in three perinatal human specimens presenting with a median orbit and proboscis. One head was sectioned in the sagittal plane and two in the coronal plane. The course of each neurovascular bundle arising from the maxillary artery and nerve was used to facilitate the identification of the various parts of the palatine bone. The data obtained were used to outline the palatine component of the maxillopalatine mass as it presented on the inferior aspect of a dried cyclops skull. The suggestion is made that the abnormalities of the palatine bone in human cyclopia are secondary to the absence of the presphenoid and the nasal cavity.

Female↗
PubMed1989

Upper jaw in human cyclopia.

In human cyclopia the upper jaw forms a solid bony mass between the median orbit and the oral cavity. The skeletal elements forming the upper jaw have been studied in serial sections through the median third of the head in 3 perinatal human specimens presenting with a median orbit and proboscis. One head was sectioned in the sagittal plane and 2 in the coronal plane. The upper jaw has also been studied in a dried cyclops skull and in a desiccated cyclops head in which the roof of the orbit had been removed. The data obtained demonstrate the particular contributions made by the lacrimal bones, the maxillae and the palatine bones to the upper jaw in human cyclopia. The effects of the absence of the frontonasal process contribution and of the absence of the nasal cavity on the upper jaw in cyclopia are considered.

Abnormalities, Severe Teratoid↗
PubMed1988

Nonpenetrating vascular injury to the subclavian artery.

Blunt subclavian artery injury has been uncommonly reported in the literature. Recent encounter with three such injuries prompted us to review our experience over the past 10 years uncovering only one additional case. These four cases and a review of pertinent literature form the basis for this article. Key clinical issues include a high index of suspicion in patients sustaining major blunt deceleration and rotational or direct injuries to the neck, thorax, and/or upper extremities. Prompt diagnosis remains obscured by the presence of severe associated injuries, the treatment of which requires prioritization. Arteriography is invaluable to elucidate injury because prompt vascular control is dictated by various approaches depending on the location. Expeditious surgical repair is indicated to prevent complications of hemorrhage, pseudoaneurysm, thromboembolism, and/or arteriovenous fistula. Long-term results appear to be good with major morbidity related to associated neurologic, soft tissue, and bony injuries.

Adolescent↗