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Biomedical subjects

M Hickey

Publications and source records attributed to M Hickey.

At least 55 records · Page 3Linked to original sources
PubMed1998

Internal mammary artery to coronary artery bypass in paediatric cardiac surgery.

The internal mammary artery is regarded as the optimal conduit for coronary artery bypass grafting in adults. Use of this conduit in paediatric surgery is rare and has been reported mainly in patients with Kawasaki's disease. We report five patients who required internal mammary-coronary artery grafting due to adverse anatomical disposition of the coronary artery. In two cases an internal mammary graft was required during correction of transposition of the great arteries. The other cases involved correction of a left coronary artery arising anomalously from the pulmonary artery. Late angiography shows satisfactory growth and patency of the conduits.

Coronary Angiography↗
PubMed1998

Precise measurements of intrauterine vascular structures at hysteroscopy in menorrhagia and during Norplant use.

Using currently available equipment for panoramic hysteroscopy, the size of images viewed cannot be accurately judged because of the magnifying and distorting effects of the objective lens. This study has demonstrated that magnification by the hysteroscope lens can alter the apparent size of images by up to 27%. An additional effect of lens distortion can alter the apparent size of images viewed by up to 28%, depending on the position of the image in the field of view. These effects are independent and may be additive. Thus, the apparent size of intrauterine structures at hysteroscopy may bear little resemblance to their actual size. Image-correction methods are described which reduce the effects of image magnification on the apparent size of an object viewed through the hysteroscope to 7%, and the effect of distortion to 3 %. This technique can greatly improve the accuracy of measurement at hysteroscopy, and has been utilized in this study for the precise measurement of superficial endometrial vascular diameter (mean+/-SEM) in 34 Norplant users (120+/-11.6 microm) and 20 women with spontaneous menorrhagia (74+/-7.2 microm). It has also confirmed the presence of scattered dilated vessels (up to 777 microm in diameter) on the endometrial surface in some Norplant users.

Adolescent↗
PubMed1997

Promoting physician productivity through a variable compensation system.

Integrated delivery systems must find ways to achieve optimal physician productivity and accountability, while fostering an entrepreneurial attitude among physicians. Lovelace Health Systems, Albuquerque, New Mexico, has implemented a variable compensation system designed for this purpose. An assessment of Lovelace's physician productivity had indicated performance well below national medians. To offer physicians a strong incentive to increase productivity, Lovelace developed a variable compensation system based on the resource-based relative value scale and relative value units. Lovelace also developed benchmark productivity targets.

Delivery of Health Care, Integrated↗
PubMed1996

Patient satisfaction in the ambulatory setting. Influence of data collection methods and sociodemographic factors.

To evaluate the impact of patient characteristics and method of data collection on satisfaction results used for the comparison of practice locations, questionnaires were distributed to 1,208 adult outpatients at five medicine clinics, either on-site or by mail. Patient dissatisfaction with three service domains was measured: communication with the provider, courtesy of the office staff, and timeliness of care. Practice location, survey methodology, and patient characteristics were significant predictors of dissatisfaction, and adjustment for the latter two factors affected the rankings of practices by dissatisfaction rates for all three domains. Further study of the impact of patient characteristics and method of data collection should be conducted before the comparison of unadjusted satisfaction results becomes the accepted standard.

Adult↗
PubMed1996

A comparison of mechanisms underlying disturbances of bleeding caused by spontaneous dysfunctional uterine bleeding or hormonal contraception.

Recent research has not been able to demonstrate close endometrial morphological correlations with specific abnormalities of menstrual bleeding, but has pointed to an increasing number of molecular mechanisms that may be involved in the occurrence of certain forms of abnormal uterine bleeding. Ovulatory and anovulatory dysfunctional uterine bleeding (DUB) and progestogen-related breakthrough bleeding (BTB) are three conditions with quite different clinical characteristics. It is also probable that the local endometrial molecular mechanisms associated with these three menstrual disturbances are quite different. Ovulatory DUB is associated with a series of vascular and haemostatic disturbances that all appear to contribute to increased loss of blood and tissue fluid at menstruation. Anovulatory DUB is associated with obvious disturbances of endometrial histology, vascular morphology and fragility, with variable and increased blood flow. Progestogen-related BTB is associated with a multitude of morphological and functional endometrial changes that appear to relate predominantly to a patchy capillary origin for the bleeding. Many molecular and cellular changes have been observed in all three conditions. It is not yet known whether there is a single, but different, underlying mechanism responsible for these multiple abnormalities in each of the three clinical situations.

Anovulation↗
PubMed1996

Endometrial vasculature in Norplant users: preliminary results from a hysteroscopic study.

Long-acting progestogenic contraceptives are frequently associated with disturbances of menstrual bleeding patterns. In particular, irregular, frequent and prolonged bleeding are commonly seen. The mechanism of this irregular bleeding is unknown, but changes in the endometrial vasculature are thought to be of importance. In endometrial biopsies from Norplant users, an increase in endometrial microvascular density has been observed after 3-12 months. Morphological changes in endometrial capillaries following progestogen exposure have suggested an increase in vascular fragility. Little is known about the structure and function of the endometrial vasculature in vivo following exposure to exogenous contraceptive steroids. This study has developed techniques for the assessment of vascular fragility by imposing a mechanical stress on the endometrium and observing subsequent bleeding under direct vision. The techniques were used in a preliminary examination between 1 and 9 months after Norplant insertion, and the study identified a number of morphological and functional characteristics of Norplant-exposed endometrium.

Adolescent↗
PubMed1996

Immunohistochemical study of endometrial microvascular basement membrane components in women using Norplant.

The mechanisms responsible for progestogen-induced breakthrough bleeding remain unexplained. The aim of the present study was to examine the expression of three basement membrane components, collagen IV (CIV), laminin and heparan sulphate proteoglycan (HSPG), by immunohistochemistry in sections of endometrium from women receiving the subdermal levonorgestrel implant (Norplant) and normally cycling women. Control biopsies were obtained from 20 normal subjects from Melbourne, Australia, and pre- and post-Norplant-insertion biopsies were obtained from 11 women from Sydney, Australia, with between 3 and 6 months Norplant exposure. It was postulated that in Norplant users a decrease in the amount of basement membrane material present around endometrial vessels may be responsible for increased capillary fragility. The results, however, showed that for all three components, Norplant biopsies exhibited vascular basement membrane immunostaining at least as intense as that found in the mid-late secretory phase of the normal cycle. During the normal cycle, HSPG was only detected in approximately 40% of vessels with CIV and laminin immunoreactivity, and menstrual biopsies demonstrated reduced staining for all three components. Several biopsies exhibited a degree of regional variability in staining intensity, and Norplant biopsies exhibited areas of discrete, decidual-like stromal immunostaining for CIV and laminin. Although no differences were found in microvascular basement membranes in Norplant users that might explain capillary fragility, it is possible that other techniques could yield information on changes in the integrity of basement membrane components that might influence basement membrane strength.

Adolescent↗
PubMed1996

Microvascular density in conditions of endometrial atrophy.

Irregular menstrual bleeding in users of hormonal contraception represents the single major reason for discontinuation of these contraceptive methods. The mechanisms which underlie these bleeding disturbances are poorly understood, but appear to be associated with changes in the endometrial microvasculature following abnormal patterns of sex steroid exposure. Endometrial microvascular density is known to be increased in users of the low-dose levonorgestrel contraceptive implant, Norplant. This study explores microvascular density in other conditions of spontaneous (post-menopausal) and induced (danazol and goserelin) endometrial atrophy. Endometrial biopsies were fixed, paraffin-embedded and sections were immunostained using anti-CD34 antibody to identify vascular endothelial cells. The mean microvascular density (+/-SEM) for control samples was 186 +/- 8 vessels/mm2. There were no statistically significant changes in vascular density observed across the menstrual cycle. Mean microvascular density in spontaneous and induced endometrial atrophy did not differ significantly from that observed in the control population. The mean microvascular density was 230 +/- 17 vessels/mm2 in 31 postmenopausal women, 269 +/- 67 vessels/mm2 in 25 subjects treated with danazol was and 191 +/- 45 vessels/mm2 in nine subjects treated with goserelin. These findings suggest that the mechanisms controlling microvascular density in conditions of endometrial atrophy may vary according to the nature of the atrophic stimulus.

Adult↗
PubMed1995

Energetic consequences of flight speeds of foraging red and hoary bats (Lasiurus borealis and Lasiurus cinereus; Chiroptera: Vespertilionidae)

We used Doppler radar readings of the flight speeds of foraging, lactating female Lasiurus borealis (N=826) and Lasiurus cinereus (N=544) to test morphologically based predictions about their flight performance. Both species flew at speeds (V=6.7 and 7.7 m s-1, respectively) that differed significantly from predicted minimum power speed (Vmp; 4.0 and 5.08 m s-1, respectively) or predicted maximum range speed (Vmr; 5.25 and 6.69 m s-1, respectively), perhaps reflecting the active pursuit of moths performing evasive manoeuvres. Estimates of costs of flight and lactation are combined with data on prey size together with encounter and capture rates to illustrate the energetic benefits accruing to these species when they forage in concentrations of insects.

Journal Article↗
PubMed1994

Innovative generalist programs: academic health care centers respond to the shortage of generalist physicians.

Academic health care centers increasingly are exploring innovative ways to increase the supply of generalist physicians. The authors review successful innovations at representative academic health centers in the areas of recruitment and admissions, undergraduate medical education, residency training, and practice support. Lessons learned focus on those areas that have demonstrated improvements in the number and quality of physicians trained in family practice, general pediatrics, and general internal medicine. Successful recruitment of generalism-oriented applicants requires identification and tracking of rural, minority, and other special groups of students at the high school and college levels. Academic health care centers that provide early, sustained, community-based, ambulatory experiences for medical students and residents encourage trainees to maintain and choose generalist careers. Finally, academic health care centers that link with community providers and with state government encourage the retention of generalist physicians through continuing education and teaching networks.

Academic Medical Centers↗
PubMed1994

Vero cytotoxin-producing Escherichia coli O157 in beefburgers linked to an outbreak of diarrhoea, haemorrhagic colitis and haemolytic uraemic syndrome in Britain.

Vero cytotoxin (VT)-producing Escherichia coli O157 (O157 VTEC) were isolated from a raw beefburger obtained from a retail source linked to a small community outbreak of O157 VTEC infection in Wales. Strains from the meat and from seven of eight patients belonged to phage type 49 and were indistinguishable by their VT-type, plasmid content and hybridization with DNA of a VT-encoding phage from an O157 VTEC strain. This first report of the isolation of O157 VTEC from a beef product in Britain supports the view that there is a bovine reservoir for this organism.

Adolescent↗
PubMed1993

Energy as a central factor in the self-assessment of health.

This article explores the role of energy in conceptualization of health, based on self-reported health ratings in 310 women (master's-prepared nurses) ages 50 to 70 years. The health self-assessment instrument consists of 1 global and 10 specific items. The item energy level emerged as central--loading on both the psychosocial health and physiologic health factors and accounting for 48% of variance of Global Health Self-Assessment. These findings build on the World Health Organization definition of health as a synthesis of psychosocial and physiologic well-being; energy level is key to an integrated view of health.

Activities of Daily Living↗