Biomedical subjects
Publications and source records attributed to C Norris.
Motion sickness is a common phenomenon affecting most patients at some point in life. Car sickness, airsickness, seasickness, and space sickness all involve a neural mismatch or confusion between the vestibular, visual, and proprioceptive systems that produces the symptoms of motion sickness. Therapy is directed toward decreasing conflicting sensory input, controlling nausea, and speeding the process of adaptation.
BACKGROUND: Patients with syncope of unknown etiology after negative noninvasive and electrophysiological testing may suffer from recurrent disability. Syncopal episodes are often too infrequent and unpredictable for detection by conventional ambulatory monitoring techniques. METHODS AND RESULTS: A long-term subcutaneous monitoring device was implanted in patients with negative ambulatory monitoring, tilt table and electrophysiological testing to establish cardiac rhythm during spontaneous syncope. Sixteen patients aged 57 +/- 19 years with a mean of 8.4 +/- 4.4 previous episodes of syncope underwent device implantation. Fifteen patients (94%) had recurrent syncope 4.4 +/- 4.2 months after implantation. The remaining patient has not had recurrent syncope and continues to be followed. A diagnosis was obtained in every patient who had recurrent episode. Syncope was secondary to sinus arrest in 5, atrioventricular block in 2, ventricular tachycardia in 1, supraventricular tachycardia in 1, and nonarrhythmic in 6. Successful therapy was implemented in all 15 patients, without recurrence of syncope during 13.0 +/- 8.4 months of follow-up. CONCLUSIONS: Unexplained syncope in patients with negative investigations has a broad spectrum of etiologies, the most common of which is bradycardia. An implantable long-term monitoring device is useful for establishing a diagnosis when symptoms are recurrent but too infrequent for conventional monitoring techniques.
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The purpose of this study was to compare the cost of a day spent in an intensive care unit and a day spent on a general nursing unit. A descriptive design was used, based on patient level data, to examine and compare unit costs per day for each of the ICU and non-ICU portions of a patient's hospital stay. Records from 386 patients who were treated in a general medical/surgical ICU were analyzed. Records for patients who received both ICU and non-ICU care during their stay were retained. Patients were categorized according to whether they had received surgical care prior to admission to the ICU (surgical group) or had no surgical care (medical group). The groups were further divided, based on whether they were discharged from hospital (survivors), or died following transfers from the ICU (non-survivors). All four groups; surgical or medical, survivors and non-survivors, were analyzed separately. The ICU direct costs per day for survivors were between six and seven times those for non-ICU care. A one day substitution of general ward for ICU care would result in a cost reduction of $1,200 per patient for survivors. The results suggest that the savings achieved by moving a patient from ICU to non-ICU care are considerable, particularly for less severe surviving patients. In making such decisions, however, clinicians must examine prospective benefits as well as costs. If the health outcomes are not influenced, the savings from substitution are considerable, and there is a strong economic argument for substitution.
The pre-operative images of three patients with biopsy proven esthesioneuroblastoma are presented. The role of computed tomography (CT) and magnetic resonance imaging (MRI) in the pre-operative determination of tumour extent is discussed.
OBJECTIVE: To analyze differences in intensive care unit (ICU) utilization between a Canadian province and a U.S. area. DESIGN: Retrospective data analysis of hospital discharge data and existing data from an international study of severity of illness in ICU patients. SETTING: Administrative data for the province of Alberta and the four counties of western Massachusetts for the years 1990 to 1991 were used. Detailed data on consecutive ICU admissions from two Alberta hospitals, one western Massachusetts hospital, and 24 other U.S. hospitals for 3 months in 1991 were used. MEASUREMENTS AND MAIN RESULTS: ICU use and hospital mortality rates were compared for 50,030 hospital admissions divided into 11 patient groups. ICU days per million population were two to three times as great in western Massachusetts as in Alberta. The primary reason was higher ICU incidence (percent of hospitalized patients treated in the ICU) rather than a difference in hospital admission rate or length of ICU stay. ICU incidence in western Massachusetts was significantly higher in ten of 11 patient groups--for the coronary bypass surgery group, there was no difference. The hospital mortality rate in western Massachusetts was similar to, or higher than, the mortality rate in Alberta. In Alberta, a much higher proportion of ICU patients received mechanical ventilation. For elective surgery patients, the ICU severity of illness was lower in western Massachusetts and in other U.S. hospitals than in Alberta. CONCLUSIONS: Western Massachusetts hospitalized patients are more likely to be treated in an ICU than are similar patients in Alberta. There is no evidence that the greater ICU utilization in western Massachusetts led to a lower hospital mortality rate.
The list of distinguishing morphological features of hair cells includes: Type I and Type II afferent innervation, and length, shapes and arrangements of stereo- and kinocilia. We now add to this list the shapes of the hair cells themselves and their placement within the mechanosensory organ, in this case the semicircular canal. Although hair cells of the crista ampullaris of the frog are only of Type II they may now be further classified into three sub-groups according to shape: club-, cigar- and pear-shaped. The cigar- and club-shaped hair cells are each about 40% while the pear-shaped cells are about 20% of the total numbers of hair cells in the crista. The differently-shaped hair cells also distribute differently along the crista. The cigar- and club-shaped are more-or-less uniformly distributed with somewhat higher concentrations at the ends of the crista than in the center. The pear-shaped hair cells, on the other hand, are mostly concentrated toward the center of the crista. This distribution of the pear-shaped hair cells, and their shape is reminiscent of the distribution of calyceal endings (Type I hair cell) in the cristae of amniotes [Goldberg et al., Hear. Res. 49, 89-102 (1990) in Chinchilla; Fernandez et al., Soc. Neurosci. Abstr. 17, 312 (1991) in Monkey]. There are some quantitative differences between hair cells of the same shape but from different portions of the crista. For instance, pear-shaped hair cells of the center are generally of greater cross-sectional area than those of the ends.(ABSTRACT TRUNCATED AT 250 WORDS)
OBJECTIVE: Both zinc (Zn) and magnesium (Mg) are widely used as nutritional supplements and the possibility was considered that Zn may interfere with the absorption of Mg, similar to previously reported results [1,2] obtained with the same dose of supplemental Zn on the absorption of calcium (Ca). METHODS: Mg absorption studies and metabolic balances of Mg and of Zn were carried out in three groups of adult males in a metabolic research unit during the intake of supplemental doses of 142 mg Zn as Zn sulfate (ZnSO4) during Ca intakes of 230, 500 and 800 mg/day. RESULTS: The Zn intake of 142 mg/day decreased the Mg balance and Mg absorption only during the 500 mg Ca intake compared to control values. However, the overall effect of the high Zn intake of the three groups combined, regardless of the Ca intake, was a highly significant decrease of Mg absorption and of the Mg balance. CONCLUSION: Zn supplements of 142 mg/day decreased Mg absorption and the Mg balance significantly during all Ca intakes for the three groups combined.
OBJECTIVE: In view of the widespread use of magnesium (Mg) as a nutritional supplement, we investigated whether Mg would affect the absorption of calcium (Ca) as the intestinal absorption sites for Mg and Ca differ. METHODS: The intestinal absorption of Ca, using 47CaCl2 as the tracer, and metabolic balances of Ca, phosphorus (P) and Mg were determined in five adult males under strictly controlled dietary conditions in control studies and during Mg supplementation. Mg was given as magnesium oxide (MgO) in 10 studies during two Ca intakes: five studies during a low Ca intake of 241 mg/day and five studies during a normal Ca intake of 812 mg/day. Dietary Mg intake ranged from 241 to 264 mg/day in control studies. During Mg supplementation, the total Mg intake ranged from 789 to 826 mg/day. RESULTS: There was no change of the intestinal Ca absorption during Mg supplementation during the two Ca intakes. The only change was the higher 1-hour 47Ca plasma level in the 47Ca absorption studies during the high Mg intake. Urinary Ca increased during Mg supplementation only during the low Ca intake, the Ca balance became more negative but this difference was not significant. There was also no change in Ca excretion or Ca balance during the high Mg intake at the normal Ca intake of 800 mg/day. P balance studies showed a slight decrease in urinary P and an increase in fecal P, but the P balances did not change. Mg balances were negative in control studies during the two Ca intakes. Supplemental Mg increased both urinary and fecal Mg excretion and the Mg balance became positive, but these differences were not significant. CONCLUSION: The increased Mg intake of 826 mg did not affect intestinal Ca absorption determined with tracer doses of 47Ca during Ca intakes of 241 and 812 mg/day.
OBJECTIVE: To reduce surgical waiting lists at the University of Alberta Hospitals. A cost reduction program was initiated, allowing more cases to be performed on the same budget. Reducing the cost of delivering health care services has become necessary as demands upon the system increase. METHODS: Data were retrospectively gathered on patients having open heart surgery at the University of Alberta Hospitals between March 1, 1991 and February 29, 1992. Group 1 were patients operated on before the start of the cost reduction program (September 1, 1991) and group 2 were those operated on after. Student's t test and logistic regression were use to compare population characteristics and to correlate dependent variables. RESULTS: Demographic features and severity indices were not different. Operating time decreased from 4.5 +/- 1.5 to 4 +/- 1 h, P < 0.002. Preoperative, intensive care unit (ICU) and postoperative ward length of stay were reduced (P < 0.002). Total length of stay went from 19.3 +/- 22.7 to 13.8 +/- 10.7 days, P < 0.001. Operating room, nursing and x-ray costs decreased, P < 0.002. Hospital costs declined from $14,182 +/- 16,464 to $10,710 +/- 7,332, P < 0.001. Multiple regression showed hospital stay, ICU, operating room time, severity of illness and age to be significant determinants of cost, P < 0.03 for each. Waiting time and number of patients on the waiting list declined significantly as surgical lists increased. Mortality and rate of readmission following discharge were not different between the two groups. CONCLUSIONS: Substantial cost savings can be made by changing practice patterns, without adverse consequences. ICU and hospital length of stay are the most important cost determinants.
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Synaptic bodies (SBs) associated with rings of synaptic vesicles and well-defined, pre- and post-synaptic membrane structures are indicators of maturity in most hair cell-afferent nerve junctions. The role of the SBs remains elusive despite several experiments showing that they may be involved in storage of neurotransmitter. Our results demonstrate that SBs of the adult posterior semicircular canal (SCC) cristae hair cells become less electron dense following incubation of the SCC with the transmitter-depleting drug tetrabenazine (TBZ). Objective quantification and comparison of the densities of the SBs in untreated and TBZ-treated frog SCC demonstrated that TBZ significantly decreased the electron density of SBs. This reduction in electron density was accompanied by a reduction in firing rates of afferent fibers innervating the posterior SCC. A second transmitter-depleting drug, guanethidine, previously shown to reduce the electron density of hair cell SBs, also reduced the firing rates of afferent fibers innervating the posterior SCC. In contrast, the electron density of dense granules (DG), similar in size and shape to synaptic bodies (SB) in hair cells, did not change after incubation in TBZ, thus indicating that granules and SBs are not similar in regard to their electron density. The role of SBs in synaptic transmission and the transmitter, if any, stored in the SBs remain unknown. Nonetheless, the association of the lessening of electron density with a reduction in afferent firing rate provides impetus for the further investigation of the SB's role in neurotransmission.
The topical antifungal Sch-39304 is a racemic compound comprised of two enantiomers, Sch-42427 and Sch-42426, only one of which (Sch-42427) is pharmacologically active. The pure enantiomers have a lower melting point and, therefore, a higher solubility than the racemic compound. Because of these differences in physicochemical properties, the concentration of the pure enantiomers in vehicles and in the skin was predicted to be an order of magnitude higher than the racemic compound. It was hoped that the pharmacological activity would also be higher. By measuring the flux of the chiral forms through human cadaver skin, the expected differences in skin solubility were confirmed. However, only a minimal difference between racemate and active enantiomer was observed in the lesion scores using a guinea pig dermatophyte model. By fitting the data to the Emax pharmacodynamic model, it is demonstrated that the maximum effect occurs at a concentration lower than the saturated concentration of the less soluble racemic compound. The data illustrate that the efficacy of topically active compounds may not be linearly related to drug concentration in either the vehicle or the skin.
Sch 39304 is a new broad spectrum triazole antifungal agent that is active, orally and topically, against superficial Trichophyton mentagrophytes and vaginal Candida albicans infections. Sch 39304 was compared to fluconazole (FLZ) in a T. mentagrophytes infection model in guinea pigs. Following topical administration, Sch 39304 (0.125%, twice daily, 10 days), was 5-8-fold more effective than FLZ, based on culture and lesion score results. Following oral administration, Sch 39304 (2.5 mg kg-1, once daily, 10 days) produced a dramatic reduction in lesion scores and was 20-fold more active than FLZ; however, due to the length of time it takes for the drugs to reach the infected area of the skin and eradicate the infections, most animals remained culture positive with both drugs. Sch 39304 was also compared with FLZ in a vaginal C. albicans infection in hamsters. Following oral administration (4 days), Sch 39304 (1.6 mg kg-1), cured all hamsters and was 4-fold more active than FLZ. In addition, Sch 39304 as a single oral dose (10 mg kg-1) also cured all hamsters. When treatment was intravaginal (8 days), Sch 39304 was again more active than FLZ (2-fold), and also micronazole (8-fold), with 100% of the hamsters cured at concentrations as low at 0.025%.
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Fusarium species are saprophytic molds and important plant pathogens, although they are increasingly recognized as agents of human mycosis. Frequently, the infection is superficial. Deep tissue infection may occur as an opportunistic hyalohyphomycosis, and wide dissemination is common in immunocompromised hosts. We describe a novel case of disseminated hyalohyphomycosis caused by F. napiforme in a patient with acute myelogenous leukemia. The clinical manifestations of this infection were similar to those attributed to infection with other species. In vitro susceptibility testing demonstrated resistance to amphotericin B and flucytosine, and progressive infection was documented until recovery of granulocyte function. The distinguishing clinical mycologic characteristics of this opportunistic mold are the unique turnip- or lemon-shaped microconidia. F. napiforme is a new agent of hyalohyphomycosis, further emphasizing the importance of Fusarium species as opportunistic molds.
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In a previous study dietary supplementation with 140 mg zinc (Zn) as Zn sulfate (ZnSO4) per day significantly decreased absorption of calcium (Ca) during a low Ca intake (230 mg/day) but not during a normal Ca intake (800 mg/day). The purpose of the present study was to determine whether smaller doses of Zn would also inhibit Ca absorption during the 230 mg Ca intake, and whether the 140 mg dose of Zn would inhibit Ca absorption during a Ca intake less than 800 mg/day. To investigate the first aspect, 100 mg Zn as ZnSO4, was given daily during a low Ca intake (230 mg/day) in six studies, and in the second phase, 140 mg Zn as ZnSO4 was given during a Ca intake of of 500 mg/day in five studies. Intestinal absorption of Ca was determined with tracer doses of 47CaCl2 in control studies and in the two Zn supplementation studies. Results showed that 100 mg Zn/day during a low Ca intake (230 mg/day) did not inhibit Ca absorption and that 140 mg Zn given during the 500 mg Ca intake also did not affect the absorption of Ca.