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Biomedical subjects

R Lane

Publications and source records attributed to R Lane.

At least 55 records · Page 3Linked to original sources
PubMed1995

Disposition of lorazepam in diabetes: differences between patients treated with beef/pork and human insulins.

The pharmacokinetics of lorazepam was examined in 10 male patients with insulin-dependent diabetes mellitus before and following treatment with neomycin and cholestyramine. Neomycin and cholestyramine were given in an attempt to block the enterohepatic circulation of lorazepam and so to permit an in vivo estimate of hepatic glucuronidation. The volume of distribution and clearance of free lorazepam in diabetic patients were not significantly different from the corresponding estimates in 14 normal controls. Neomycin and cholestyramine increased the clearance of lorazepam by 63% consistent with their effect in non-diabetic controls. However, patients on beef/pork insulin exhibited a greater than normal increase on this interupting regimen (125%), and had a significantly greater neomycin/cholestyramine cycling-interrupted clearance of lorazepam than either normal controls or patients on human insulin (15.4 vs. 6.96 and 7.87 ml.min-1.kg-1). The clearance was correlated positively and significantly with HbA1c and glycated proteins (fructosamine), but only in patients on human insulin. Thus, the pharmacokinetics of lorazepam was not altered in patients with insulin-dependent diabetes mellitus. However, it is possible that there are differences in the rate and extent of hepatic glucuronidation and enterohepatic circulation of lorazepam between patients treated with beef/pork and human insulins and between diabetics treated with beef/pork insulin and non-diabetic controls.

Adolescent↗
PubMed1995

Carotid endarterectomy for asymptomatic carotid artery stenosis: patients with severe bilateral disease a high risk subgroup.

Carotid endarterectomy if advised for asymptomatic disease must be associated with a low peri-operative morbidity and mortality and satisfactory long-term results. Over a 12 year period between 1978-1989 181 carotid endarterectomies were performed on 163 patients with asymptomatic carotid artery stenosis. There were 112 males and 51 females with a mean age of 64.9 years. All patients had a high-grade lesion (> 70% stenosis). The combined operative mortality and stroke rate was 2.8%. On long-term follow up six patients suffered a stroke. Only one patient however sustained a stroke in the same territory as the previously operated carotid artery. Four years following surgery 78% of patients were alive. Carotid restenosis or occlusion occurred in 8.3% of the remaining patients, all of whom were asymptomatic. All the immediate postoperative strokes occurred in patients with severe bilateral carotid artery disease. These patients with severe bilateral disease appear to constitute a high risk sub-group for peri-operative stroke. The role of 'normal pressure-hyperperfusion breakthrough' syndrome as the presumed aetiology of two of the postoperative cerebral haemorrhages is discussed.

Aged↗
PubMed1995

The economic cost of elective carotid endarterectomy.

Cost awareness and accountability for the use of health care resources have become major issues for clinicians. In order to identify the economic costs associated with carotid endarterectomy (CEA), a retrospective review of 50 elective CEA between May 1993 and April 1994 was undertaken. Despite our belief [based on the Australian National Diagnostic Related Groupings (ANDRG)], that our resource utilization had been refined to produce a median length of stay significantly below the New South Wales (NSW) State average, this study has identified several areas of non-productive expenditure. The mean cost of CEA per patient was $7053. This figure includes non-productive expenditure of $793 per patient in the pre-operative period and $395 per patient in the postoperative period. If these costs, which did not contribute to patient care, were removed the mean cost of CEA would be $5865. The major causes of non-productive resource utilization included prolonged pre-operative stay, duplicated or omitted investigations, as well as the use of the Intensive Care Unit for patient monitoring in the postoperative period.

Aged↗
PubMed1994

Pilomatrical carcinosarcoma of the cheek with subsequent pulmonary metastases. A case report.

We report a case of malignant pilomatrixoma with a pronounced biphenotypic morphology. The lesion, which was excised from the cheek of a 36-year-old man, was composed of a large pilomatrixoma lying within a spindled, sarcomatoid stroma. Fourteen months later, the tumor metastasized to the right upper lobe of the lung. We describe the tumor's pathology, histology, and immunochemistry and discuss the differential diagnosis. We also speculate on its histogenesis.

Adult↗
PubMed1994

Reducing the economic burden of depression.

Depressive illness places an enormous economic burden on health services, the community and the individual patient. It is a serious medical disorder associated with high levels of social and physical disability. Antidepressant drug therapy can produce significant improvement in the majority of patients. However, despite its high prevalence depressive illness is frequently undetected, misdiagnosed or inappropriately treated. The selection of a cost-effective antidepressant requires a broad evaluation of the risks, costs and benefits. A choice should not be made on prescription drug costs alone but on the basis of the overall value a treatment option offers in the management of illness. Benefits, such as improved treatment compliance, reduced toxicity in overdose, long-term safety and efficacy in the prevention of relapse and recurrence of depression, improved patient quality of life and decreased accident liability all have cost implications which must be considered when determining the relative cost of medication.

Antidepressive Agents↗
PubMed1993

Direct diagnosis of myotonic dystrophy with a disease-specific DNA marker.

BACKGROUND: Myotonic dystrophy is the most common inherited form of muscular dystrophy affecting adults. Its symptoms are not confined to muscle, and variability in their nature and in the patient's age at their onset can make diagnosis difficult. A specific unstable DNA sequence associated with myotonic dystrophy has recently been identified. We describe the use of a DNA probe (p5B1.4) that can detect this mutation directly, improving the accuracy and speed of diagnosis. METHODS: We analyzed DNA extracted from the peripheral-blood lymphocytes of 112 unrelated patients with myotonic dystrophy and their families, using molecular genetic techniques. Southern blot analysis and amplification with the polymerase chain reaction were used to determine the extent of expansion of the unstable DNA sequence. RESULTS: Probe p5B1.4 allowed direct identification of the myotonic dystrophy mutation in 108 of the 112 unrelated patients. In three families for whom the clinical and genetic data obtained with linked probes were ambiguous, the probe identified persons at risk for symptoms of this disorder and demonstrated that a possible sporadic case of myotonic dystrophy was familial. In one of these families the size of the unstable myotonic dystrophy-specific fragment decreased on transmission to offspring, who remained asymptomatic. CONCLUSIONS: The diagnosis of myotonic dystrophy is improved by the use of a probe that detects directly the mutation responsible for this disorder.

Adolescent↗
PubMed1993

A method for the continuous measurement and display of pulmonary resistance in man.

1. We have validated a method for the continuous display and 'on-line' measurement of total pulmonary resistance in man, using a hybrid digital/analog computer. 2. The basic variables, which are measured by standard techniques, are flow rate of the mouth (V) and oesophageal pressure (Poes), and these are the only analog inputs necessary to the computer. 3. Resistance (RL,cont) is calculated continuously as: RL,cont = (Poes-V/C)/V where V is tidal volume and C is the dynamic compliance. RL,cont is continuously displayed as an analog signal on an oscilloscope. 4. Changes in resistance, measured by this method over a wide range of values in three subjects, showed an almost exact correlation with those measured by a standard method (Mead-Whittenberger).

Airway Resistance↗
PubMed1993

Metabolic acidosis and breathlessness during exercise and hypercapnia in man.

1. A previous study showed that when combined with exercise in normal subjects, hypercapnic and hypoxic ventilatory stimuli did not have a specific effect on the intensity of the sensation of breathlessness in addition to their stimulation of ventilation. The aim of the present study was to assess the significance of another reflex ventilatory stimulus, metabolic acidosis, in the genesis of this sensation. 2. Six subjects performed progressive exercise tests (mean workload, 103 W; range, 88-125 W) with normal acid-base status. Following NH4Cl-induced metabolic acidosis (mean change in base excess, -3.6 mmol l-1; range, -0.3 to -6.8 mmol l-1) exercise was repeated (mean workload, 91 W; range, 53-116 W) such that the combined ventilatory stimulation resulted in levels of ventilation (mean maximum, 65 l min-1) 'matched' to those resulting from exercise alone. A third, 'matched ventilation', exercise test was performed during metabolic acidosis but with end-tidal PCO2 controlled to a normal level (mean workload, 56 W; range, 17-103 W). Breathlessness was assessed using a visual analogue scale (VAS). 3. Progressive hypercapnic ventilatory stimulation was given before (mean maximum end-tidal PCO2 (PET,CO2), 61 mmHg) and during metabolic acidosis (mean maximum PET,CO2, 57 mmHg) to achieve the same peak level of ventilation (mean maximum, 59 l min-1). Breathlessness was assessed with the VAS. 4. As ventilation increased during a test, there were no statistically significant differences in the increasing breathlessness scores with metabolic acidosis compared to control, for either exercise (mean VAS, 22 mm vs. 24 mm) or progressive hypercapnia (mean peak VAS, 31 mm vs. 32 mm). 5. These results do not support the idea that metabolic acidosis is associated with a change in the relationship between the intensity of breathlessness and ventilation; this is similar to results found with other reflex ventilatory stimuli. 6. These findings are consistent with the hypothesis that the degree of reflex ventilatory activation is an important determinant of the intensity of the sensation of breathlessness in healthy humans, irrespective of the exact nature of ventilatory stimulus.

Acidosis↗
PubMed1991

A microcomputer-controlled system for use in auditory physiology.

This report describes a digitally controlled system for use in auditory physiology in which signal generation and data acquisition are under the control of a single microcomputer. The system is designed to generate the complex waveforms required in neuroethological studies, and is able to generate these signals at frequencies of up to 160 kHz with a resolution of 1 Hz. The system is built around a commercially available digital hardware system, and augmented with custom components to enhance operation speed, precision and flexibility.

Hearing↗
PubMed1991

Basic techniques in pet avian clinical pathology.

An understanding of clinical pathology is extremely important for the pet avian clinician. The basics are often poorly understood by the busy practitioner. This article has served as a review for clinicians wanting the basics but having neither the time nor the resources to examine large volumes of material. This information has been designed to enable the veterinarian to understand better the limitations of the tests and the difficulties encountered by the avian technician in performing the tests so important in clinical avian practice.

Animals↗
PubMed1990

The effects of hypoxia and hypercapnia on perceived breathlessness during exercise in humans.

1. The sensation of breathlessness increases when ventilation is reflexly stimulated but it is not clear whether different stimuli have specific effects in the genesis of this sensation. 2. Our aim was to compare subjective assessments of the intensity of breathlessness at the same levels of ventilation induced by different combinations of reflex ventilatory stimuli. 3. Against a background of progressive exercise (maximum workload 170 W) in 'blinded' normal naive subjects, normoxic hypercapnia (maximum end-tidal CO2, PET, CO2, 56 mmHg) or isocapnic hypoxia (minimum O2 saturation 88%) was induced to achieve levels of ventilation (maximum 60 l min-1) 'matched' with those resulting from a higher intensity of exercise alone. Subjective breathlessness was rated with a visual analogue scale. 4. For a given ventilation, compared with exercise alone, breathlessness scores were similar during hypercapnia and were lower during hypoxia. 5. These results do not support the idea that during exercise, hypercapnia or hypoxia has a specific role in the genesis of the sensation of breathlessness. 6. The findings are consistent with the hypothesis that the degree of reflex ventilatory activation, however achieved, is an important determinant of the intensity of perceived breathlessness in healthy humans.

Adult↗