Clinical and investigative medicine. Médecine clinique et experimentale
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The urine osmolal gap is defined as the difference between measured urine osmolality and the sum of the concentrations of sodium, potassium, chloride, bicarbonate, urea and glucose. Normally, this gap is 80-100 mosmol/kg H2O. ⋯ For example, with "hybrid" metabolic acidosis, a low urine osmolal gap will suggest the absence of excessive organic aciduria (ketoacidosis) and the basis of the normal anion gap type of acidosis will be determined by the urine anion gap or "net charge". Where "hybrid" metabolic acidosis has occurred due to wide anion gap metabolic acidosis with loss of organic acid anion in the urine, the urine osmolal gap will be high and can be used in a semi-quantitative fashion to estimate the sum of urinary ammonium plus ketone body anion concentrations.
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To test the hypothesis that the reduction of ventilatory response to CO2 during nasal breathing of cold air is due to cooling of the hypothalamus, four adult male volunteers breathed either cold air (3 degrees C) or warm air (33 degrees C) through the nose by means of a face mask. Ventilation was increased to a mean of 30 l/min by increasing inspired CO2 concentration, which was adjusted so as to match ventilation in the two conditions. Cold air through the nose reduced the ventilatory response to CO2 so that with cold, higher inspired CO2 concentrations were required to produce the same ventilation as during warm air breathing. ⋯ A hand immersion water calorimeter was used to measure the peripheral vascular response to hypothalamic regulatory changes. There was no measurable change in hand heat loss, rectal, or tympanic membrane temperature. This suggests that the depressant effect of cold air breathing is mediated by skin and mucosal temperature receptors connected to the respiratory centres rather than by direct cooling of the hypothalamus.
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In order to provide information for decision making regarding urolithiasis treatment programs for the population of the Central West Region (population 1.8 million) of Ontario, we conducted an incremental cost-effectiveness analysis of standard surgery, percutaneous ultrasonic lithotripsy, and extracorporeal shock wave lithotripsy for the removal of renal and ureteric stones. Estimates of costs and effects were calculated for a 5-year period, beginning in 1985. Direct medical costs estimated were fees, both professional and technical, operating costs, and hospitalization costs for standard surgery, percutaneous ultrasonic lithotripsy, and extracorporeal shock wave lithotripsy. ⋯ At 400 procedures per year, the cost of each disability day averted by extracorporeal shock wave lithotripsy, compared to percutaneous ultrasonic lithotripsy, is $35.60. At 500 procedures per year, extracorporeal shock wave lithotripsy costs less and generates fewer disability days than percutaneous ultrasonic lithotripsy and is therefore the desired alternative. Sensitivity analyses demonstrate that cost effectiveness results are most affected by the number of procedures performed, the length of stay, and the number of disability days generated.
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Historical Article
Medicine and the two cultures: science and humanism in medicine.
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Comparative Study
Nystatin prophylaxis of fungal colonization and infection in granulocytopenic patients: correlation of colonization and clinical outcome.
Nystatin, one million units every four hours, was prospectively studied as a prophylactic antifungal agent in 164 neutropenic patients who were not initially colonized by fungi: 104 received nystatin and 60 served as controls. Fungal colonization occurred in 68/104 (65%) nystatin recipients and in 43/60 (71%) controls. However, nystatin significantly reduced multiple body site colonization and persistent oropharyngeal colonization. ⋯ Disseminated fungal infections were diagnosed in 19/111 (17%) of colonized patients, as compared to 1/53 (2%) non-colonized patients (p less than 0.02). We conclude that colonized patients are more likely to develop febrile clinical courses, to fail to respond to empiric antibiotic therapy, and to develop disseminated fungal infection. Nystatin altered colonization patterns but did not prevent disseminated fungal infection.