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Biomedical subjects

D O'Hara

Publications and source records attributed to D O'Hara.

At least 19 recordsLinked to original sources

The evaluation of a precordial ECG BELT: technologist satisfaction and accuracy of recording.

The standard method for performing electrocardiogram (ECG) recordings presents a challenge to technicians because of the need to correctly position the individual precordial electrodes according to 6 bony thoracic landmarks. A proposed new method using a 6-lead ECG BELT for precordial application was compared to the standard method to determine the level of agreement among automated interpretations. A comparison of automated interpretations from repeat standard recordings served as the control. Results indicate that BELT and standard automated interpretations disagreed significantly more frequently than repeat standard recording automated interpretations of the cardiac rhythm. The BELT's most obvious weakness was the inability to obtain a recording with a stable ECG baseline, triggering automated detection of "baseline artifact or wander," and requiring a repeat recording. These findings suggest that the ECG BELT is not adequate for clinical application in its current form.

Electrocardiography↗

Avian reovirus major mu-class outer capsid protein influences efficiency of productive macrophage infection in a virus strain-specific manner.

We determined that the highly pathogenic avian reovirus strain 176 (ARV-176) possesses an enhanced ability to establish productive infections in HD-11 avian macrophages compared to avian fibroblasts. Conversely, the weakly pathogenic strain ARV-138 shows no such macrophagotropic tendency. The macrophage infection capability of the two viruses did not reflect differences in the ability to either induce or inhibit nitric oxide production. Moderate increases in the ARV-138 multiplicity of infection resulted in a concomitant increase in macrophage infection, and under such conditions the kinetics and extent of the ARV-138 replication cycle were equivalent to those of the highly infectious ARV-176 strain. These results indicated that both viruses are apparently equally capable of replicating in an infected macrophage, but they differ in the ability to establish productive infections in these cells. Using a genetic reassortant approach, we determined that the macrophagotropic property of ARV-176 reflects a post-receptor-binding step in the virus replication cycle and that the ARV-176 M2 genome segment is required for efficient infection of HD-11 cells. The M2 genome segment encodes the major mu-class outer capsid protein (muB) of the virus, which is involved in virus entry and transcriptase activation, suggesting that a host-specific influence on ARV entry and/or uncoating may affect the likelihood of the virus establishing a productive infection in a macrophage cell.

Animals↗

The incentive effects of malpractice liability rules on dental practice behavior.

OBJECTIVES: The impact of malpractice liability rules on dental practice behavior was estimated using data from a 1992 nationwide survey of US general dentists. The study examined the premise that malpractice liability rules can affect quality of care and related resource allocation decisions by dentists, but that market features, such as relatively complete and "non-experience rated" malpractice insurance, are likely to weaken the incentive effects of malpractice liability. METHODS: General practice dentists in the United States were selected randomly, and 3,048 dentists were studied by mail survey. Secondary data on county-level characteristics were used to measure market area factors. Quality-of-care measures were derived from the survey about self-reported practice policies and behavior and participation in continuing education. Legal measures were assembled from state statutes and appellate court decisions. Ordinary least squares was used to assess the relation between legal variables and dependent variables of quality of care, continuing education, and the rate of dental output. RESULTS: Hypotheses about the effects of malpractice law on practice quality and participation in continuing education were not supported. The relation between pro-dentist law and output was supported. A number of legal provisions related to differences in practice behavior, but often in ways opposite to the expected direction. CONCLUSIONS: The direct effects of specific malpractice liability rules on dentist practice behavior often failed to point in the direction predicted by theory and were economically insignificant. It is possible that relatively complete malpractice liability insurance, coupled with "noisy" liability rules, substantially dulls the deterrent effect of malpractice liability. Other forces, such as the dentist's past malpractice claims experience, were more significant in shaping dentist behavior.

Education, Dental, Continuing↗

Superficial nasalis aponeurotic system (SNAS) flap reconstruction of nasal defects.

Reconstruction of full-thickness tissue loss of the nose, particularly in the nasal tip and supratip areas, remains a technical and aesthetic challenge. Exposure of the alar cartilage can complicate an already difficult reconstruction. Many method of reconstruction have been described. We offer an alternative to previously described techniques, utilizing the nasalis aponeurosis to provide alar coverage and bulk, in conjunction with full-thickness skin grafting to minimize contour deformity. The authors describe the technique and anatomy based on cadaveric dissection and its use in 4 patients. We have performed the superficial nasalis aponeurotic system (SNAS) flap on 4 patients with satisfactory aesthetic results. Use of the SNAS for coverage obviates the need for resection of a dog-ear, as may be the case with cutaneous or musculocutaneous flaps. Alar contour deformity is minimal. The SNAS flap is a useful technique to provide soft-tissue coverage of full-thickness soft tissue loss of the nose.

Adult↗

Trends in in-hospital mortality following acute myocardial infarction (AMI) in Victoria, 1987-1994.

BACKGROUND: Death rates from coronary hearts disease have exhibited remarkable declines in most industrialised countries. Cardiovascular mortality has been the subject of extensive research and we considered it important to analyse recent local population based data on hospital outcomes of acute myocardial infarction (AMI). AIM: To document the trends in in-hospital mortality from AMI in Victoria from 1987-1994. METHODS: This was a retrospective analysis of data from the Victorian Inpatient Minimum Database relating to all public acute care hospitals. All separations recording a principal diagnosis 410 (AMI) were selected. Changes in distribution of AMI separations, in-hospital mortality, and changes in length of stay were examined. RESULTS: The mean age of women admitted was 72 years compared with 64 years for men. Women comprised around a third of the overall sample but the proportion varied from 13% in those under 50 years to 57% among those aged 80 years and over. A striking decline in mortality was observed throughout the eight year period. The relative age adjusted decline was 33.5% (40% in males and 26% in females) with rates remaining higher in women. This decline occurred despite the increasing representation of those aged over 80 years. There was a significant decline in the mean length of stay (1.8 days) over the eight year period but this is likely to have had only minimal impact on mortality rates. CONCLUSION: We have documented welcome declines in in-hospital mortality from AMI that are not an artefact of declining lengths of stay. Our observations parallel those in similar overseas studies. Large changes in medical management have taken place from the mid 1980s and may be partly responsible, but a change in disease process cannot be ruled out.

Aged↗

The relationship between price of services, quality of care, and patient time costs for general dental practice.

OBJECTIVE: To examine the relationships between price of services, quality of care, and patient time costs in private practices of general dentists. DATA SOURCE/STUDY SETTING: In October 1992, a 3.7 percent sample of eligible general dentists in part-time or full-time private practice in 1991 was randomly drawn from a sampling frame tailored from data gathered by the 1991-1992 American Dental Association Distribution of Dentists census of all United States dentists. DATA COLLECTION: A mail survey was used to collect data on dentist demographic characteristics, dental practice characteristics practice finances, and insurance. The survey was completed and returned by 3,048 general dentists (77 percent response rate). Local area population characteristics were obtained from secondary sources. STUDY DESIGN: Two-stage least squares regression was used to evaluate the structural relationships between price of services, quality of care, and time costs to patients. Structural equations were estimated for four different quality of care measures and two time costs. PRINCIPAL FINDINGS: Price of services and quality of care were significantly related to each other. Higher quality of care was associated with higher price of services and, reciprocally, higher price of services was associated with higher quality of care. Shorter waits for a new patient appointment were associated with higher prices. Higher price of services, lower quality of care, and longer waits for a new patient appointment were related to shorter in-office waiting time. CONCLUSIONS: The implication of these findings is that if price of services is constrained, then the quality of care provided by the dentist may also be reduced.

Fees, Dental↗

The utilisation of public and private hospitals in Victoria: an issue of access?

Consumers regard access to hospital services as one of the key components of quality in health care delivery. A mixed public/private system operates in Victoria, but a morbidity collection from private hospitals was commenced only relatively recently. In 1993-94 the collection covered 82 per cent of private hospital separations, and it was considered timely to examine the utilisation patterns in the private system and compare them with those in the public system. Medical and surgical emergencies and other complex conditions and procedures are serviced largely in the public sector, whereas private hospitals are utilised for elective and less complex surgery and non-urgent conditions. Occupancy rates are around 79 per cent in public hospitals and 67 per cent in private hospitals. Elective surgery waiting list data suggest that while urgent cases are treated within a month, significant proportions wait six months or more for non-urgent surgery. Private health insurance is the main factor in determining access to and the utilisation private hospitals. The current Medicare Agreement and the move to separate the role of purchaser and provider may allow the maximal utilisation of private hospitals and diminish the burden of chronic illness.

Adolescent↗

Mortality soon after discharge from a major teaching hospital: linking mortality and morbidity.

In this pilot study, data held by the Registrar of Births, Deaths and Marriages was linked to the Patient Master Index at St Vincent's Hospital Melbourne in order to identify early post discharge deaths, and inpatient records were linked with the Victorian Inpatient Minimum Database. Between July 1991 and December 1993 there were 831 deaths within 28 days of discharge. Injuries and poisoning were the commonest cause of death in younger patients who had attended the emergency department. These were responsible for 64% of deaths under the age of 40 years. There were deaths from cardiovascular disease which had been unrecognised during the hospital stay. There is also the need to identify in hospital those at risk of suicide. Amongst inpatients who were discharged home or transferred, the risk of death was greatest in the days immediately following discharge. Policies relating to the transfer of patients need to be reviewed as the study found that 30% of patients who had been transferred to long term care facilities died within four days. In conclusion, linking mortality and morbidity data can highlight areas of hospital care where there is the potential to prevent premature death, and improve management. The outcome of coronial investigations should be transmitted to hospitals for quality assurance purposes.

Adult↗

Leaving hospital against medical advice.

Early post-discharge deaths were identified in a recent study based at St Vincent's Hospital, Melbourne, over a two and a half year period. As a result of linking patient records with the Victorian Minimum Database (VIMD) those who had discharged themselves against medical advice (ama) were identified. In this study information relating to all patients who discharged themselves ama from St Vincent's Hospital was obtained from the VIMD. We found that 1.5% of separations over the study period were discharges ama. Nearly half were over the age of 60 years. Injuries and poisoning, circulatory disorders and mental disorders were the most common diagnostic categories associated with discharge ama. The specific conditions contained within these included fractured neck of femur, cerebral occlusion and subarachnoid haemorhage. The study raises the important question of how discharge ama affects the clinical outcome in patients with such serious conditions. A follow up of such patients, which includes interviews with clinicians and families is suggested. The patients who died within 28 days were in the main elderly, suffering from malignancy. Even in these cases a knowledge of the attitudes and experiences of clinicians would be useful in order to manage optimally requests by critically ill patients for discharge.

Adult↗

Effect of standing or walking on physiological changes induced by head down bed rest: implications for spaceflight.

BACKGROUND/HYPOTHESIS: To simulate exposure to microgravity and to determine the effectiveness of intermittent exposure to passive and active +1 Gz force (head-to-foot) in preventing head-down bed rest (HDBR) deconditioning, 4 d of 6 degrees HDBR were used. METHODS: Volunteers were 9 males, 30-50 yr, who performed periodic standing or controlled walking for 2 or 4 h.d-1 in 15-min bouts, one bout per hour, or remained in a continuous HDBR control condition (0 Gz). RESULTS: Standing 4 h (S4) completely prevented, and standing 2 h (S2) partially prevented, decreases in post-HDBR orthostatic tolerance (survival rates with 30 min of upright tilt at 60 degrees). Walking, both 2 h (W2) and 4 h (W4), and S4 attenuated decreases in peak oxygen uptake compared to 0 Gz. Compared to 0 Gz, both S4 and W4 attenuated plasma volume loss during HDBR. Urinary Ca2+ excretion increased over time with HDBR; the quadratic trend for urinary Ca2+, however, was attenuated with W2 and W4. CONCLUSIONS: We concluded that various physiological systems benefit differentially from passive +1 Gz or activity in +1 Gz and, in addition to the duration of the stimulus, the number of exposures to postural stimuli may be an important moderating factor.

Adult↗

Tort reform and malpractice liability insurance.

Legal factors related to the malpractice liability insurance purchased by general dentists in the United States were investigated using a comprehensive multivariate model that assessed the contribution of legal provisions affecting the probability of a malpractice claim, the probability of a payment, and the average size of the payment. General practice dentists in the United States were selected randomly, and 3,048 dentists were studied by mail survey. A number of legal statutes (periodic payment allowed, percentage fault liability informed consent limits, limits on res ipsa loquitor, attorney fee control, some statute of limitations provisions) had the intended effect of reducing the malpractice insurance sought by dentists. Other provisions, such as binding arbitration, may have unintended cost-raising effects. Previous malpractice claims were associated with purchasing greater amounts of insurance. These findings have implications for future changes in the legal system as part of health care reform.

Dentistry↗

Malpractice premiums in 1992: results of a national survey of dentists.

According to a 1992 national survey, more than 95 percent of general dentists in the United States purchased malpractice insurance. The authors evaluated the survey findings to identify factors that had the greatest effect on dentists' insurance premium costs. Premiums were higher for dentists who had been the subject of previous complaints or claims, as well as for those who owned their practices. States with fewer lawyers had lower premiums. Finally, state limits on use of dental hygienists, number of offices and the extent of water fluoridation also affected premium levels.

Fees and Charges↗

Trendelenburg position and oxygen transport in hypovolemic adults.

STUDY OBJECTIVE: To evaluate the effect of the Trendelenburg position on oxygen transport in hypovolemic patients. DESIGN: A prospective, self-controlled sequential design. INTERVENTIONS: All patients had indwelling pulmonary artery catheters, and hypovolemia was confirmed by a pulmonary artery wedge pressure of 6 mm Hg or less. Hemodynamic and oxygen transport variables were measured with the patient supine and again ten minutes after placing the patient in the Trendelenburg position. SETTING: University-affiliated tertiary care surgical ICU. TYPE OF PARTICIPANTS: Eight postoperative adults. RESULTS: Mean arterial blood pressure increased from 64.9 +/- 4.9 to 75.6 +/- 3.5 mm Hg (P < .05), pulmonary artery wedge pressure increased from 4.6 +/- 1.1 to 7.9 +/- 0.8 mm Hg (P < .05), and the systemic vascular resistance rose to 2,965 +/- 210 from 2,302 +/- 199 dyne.sec/cm5 (P < .05). There was no significant change in cardiac index, oxygen delivery, oxygen consumption, or oxygen extraction ratio. CONCLUSION: The increase in blood pressure from Trendelenburg position is not associated with an improvement in blood flow or tissue oxygenation.

Adult↗

Malpractice claims during 1988-1992: a national survey of dentists.

Between 1988 and 1992, almost a quarter of surveyed dentists reported at least one patient complaint to malpractice insurance carriers. The incidence of claims more than doubled in that time and payment size increased nearly five times between 1988 and 1991. These and other trends in professional liability are examined in this national survey of general dentists.

Age Factors↗

Foamy changes of placental cells in probable beta glucuronidase deficiency associated with hydrops fetalis.

Mucopolysaccharidosis type VII (MPS VII, beta glucuronidase deficiency) has been described in association with non-immune hydrops fetalis. Three consecutive pregnancies in an itinerant family, which resulted in stillbirths caused by non-immune hydrops are described. The parents were closely related and there was a strong family history of storage disorders. The main clue to the diagnosis, however, came from the presence of pronounced foamy cytoplasmic change in the villous Hofbauer cells of the placenta. This raised the possibility of an inherited metabolic storage disorder. The parents were subsequently shown to have beta glucuronidase activities in the heterozygous range in leucocytes and fibroblasts which suggested that the non-immune hydrops was caused by beta glucuronidase deficiency.

Female↗

Gender differences in endocrine responses to posture and 7 days of -6 degrees head-down bed rest.

Endocrine regulation of fluids and electrolytes during 7 days of -6 degrees head-down bed rest (HDBR) was compared in male (n = 8) and, for the first time, female (n = 8) volunteers. The subjects' responses to quiet standing for 2 h before and after HDBR were also tested. In both sexes, diuresis and natriuresis were evident during the first 2-3 days of HDBR, resulting in a marked increase in the urinary Na(+)-to-K+ ratio and significant Na+ retention on re-ambulation. After the 1st day of HDBR, plasma renin activity (PRA) was increased relative to aldosterone (Aldo), plasma volume was decreased, and the renal response to Aldo appeared to be appropriate. Circulating levels of arginine vasopressin, cortisol, and ACTH were unchanged during HDBR. Plasma testosterone decreased slightly on day 2 of HDBR in males. The ratio of early morning ACTH to cortisol was lower in females than in males because ACTH was lower in females. Urinary cortisol increased and remained elevated throughout the HDBR in males only. There were no gender differences in the responses to 7 days of HDBR, except those in the pituitary-adrenal system; those differences appeared unrelated to the postural change. The provocative cardiovascular test of quiet standing before and after HDBR revealed both sex differences and effects of HDBR. There were significant sex differences in cardiovascular responses to standing before and after HDBR. Females had greater PRA and Aldo responses to standing before HDBR and larger Aldo responses to standing after HDBR than males.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗