Biomedical subjects
Publications and source records attributed to R Brubaker.
"This article addresses a... neglected, link between migration and ethnicity or nationality in Europe. It explores migrations of ¿ethnic unmixing' or ¿ethnic affinity'. Ethnic unmixing and ethnic affinity have somewhat different connotations and call attention to two distinct respects in which ethnicity may figure in such migrations: (1) as a push factors at the point of origin, and (2) as a pull factor at the point of destination. "
PURPOSE: To measure under carefully controlled conditions the effects in the rabbit eye of commonly used therapeutic agents for glaucoma. METHODS: Rabbits were outfitted in one eye with an implantable telemetric pressure transducer and monitored for several months under controlled conditions of light/ dark and handling. Effects of tonometry, handling, water drinking, and instillation of topical ophthalmic medications on intraocular pressure were recorded during each 24-hour day/night cycle. RESULTS: Pneumatonometry, animal handling, and water drinking all had an effect on intraocular pressure that in many instances was of the same magnitude as the effects of pharmacologic agents. Dorzolamide and timolol caused a sustained reduction of intraocular pressure during the nocturnal period. Epinephrine had a biphasic effect, causing an immediate pressure elevation followed by a prolonged depression. Apraclonidine, latanoprost, and pilocarpine had no measurable effect. CONCLUSIONS: Continuous telemetric measurement of intraocular pressure in rabbits permits the measurement of uncontrollable artifacts that occur with tonometric measurements and animal handling. If environmental conditions are rigidly controlled, this method is very sensitive for detecting therapeutic effects of candidates for ocular hypotensive drugs. When healthy animals are used, the method appears to be more sensitive for drugs that affect aqueous humor formation than for drugs that affect aqueous humor outflow resistance.
OBJECTIVES: To measure the effectiveness of topical 2% dorzolamide hydrochloride (Trusopt, Merck & Co Inc, Whitehouse Station, NJ) as a suppressor of aqueous humor flow in the human eye as compared with the effectiveness of 0.5% timolol maleate (Timoptic, Merck & Co Inc) and to measure the additivity of the 2 drugs. DESIGN: A randomized, double-masked, placebo-controlled study of 40 human subjects was carried out in 2 academic centers (Mayo Clinic, Rochester, Minn, and University of Uppsala, Uppsala, Sweden). The rate of aqueous flow was measured from 8 AM to 4 PM by means of fluorophotometry after administration of doses of each drug singly and both drugs together. RESULTS: Dorzolamide reduced aqueous flow from 3.07 +/- 0.63 microL/min (mean +/- SD) to 2.53 +/- 0.60 microL/min, a reduction of 18% (P < .001). Timolol reduced aqueous flow from the same beginning rate to 1.64 +/- 0.35 microL/min, a reduction of 47% (P < .001). The inhibitory effect of timolol was 2.6 times the inhibitory effect of dorzolamide (P < .001). The 2 drugs were almost completely additive, and together reduced the flow to 1.37 +/- 0.33 microL/min, a reduction of 55%. Consistent effects were observed on intraocular pressure. CONCLUSIONS: Timolol is more effective than dorzolamide as a suppressor of aqueous humor flow in the normal human eye. Timolol and dorzolamide are additive in their effects, both on aqueous flow and intraocular pressure.
The vibration from chain saws can cause vibration-induced white finger disease (VWFD). Measurements of vibration levels on the front and rear handles of different chain saw-types, and on the operator's middle finger were collected at three logging camps on Vancouver Island. Factors effecting the vibration levels on the finger and handles were investigated. The acceleration at the firing frequency was found to be the dominant factor effecting handle and finger vibration. Other factors which were investigated were: grip force; the presence of handle covers; and chain sharpening procedure. Weighted acceleration levels are calculated and this information is used to assess the latency period for fallers to develop VWF disease.
Skin necrosis associated with protein C deficiency has recently been reported to occur in hemodialysis patients. The clinical presentation and course of this syndrome appears indistinguishable from skin necrosis (purpura fulminans) seen in other settings with inherited or acquired deficiency of the naturally occurring anticoagulant proteins, protein C and S. Patients on maintenance hemodialysis may have low levels of these factors. However, patients on peritoneal dialysis have normal or elevated levels of these proteins despite documented peritoneal losses. We report two patients in whom the occurrence of protein S deficiency and subsequent skin necrosis can be related to demonstrated peritoneal dialysis-associated losses. We suggest that these losses may become critical under appropriate conditions and suggest caution in peritoneal dialysis patients requiring warfarin therapy.
Plasmacytoid T-cells (PTCs) are a histologically recognized component of some reactive nodes. To the best of the authors' knowledge, plasmacytoid T-cells have never been recognized as a distinct cell population in a reactive lymph node using cell suspension flow cytometric studies. The authors here report a case of reactive lymph node hyperplasia in which prominent aggregates of PTCs were present and a distinct cell population with an immunophenotype characteristic of PTCs was identified by flow cytometry. Aside from the recognition of PTCs, this observation is important so that cell suspensions showing a distinct population of PTCs with an "aberrant" T-cell phenotype are not misinterpreted as providing evidence for a T-cell neoplasm.
When fluorescein is administered systemically, it is metabolized to form a fluorescent compound, fluorescein monoglucuronide. The molar fluorescent intensity of this compound is less than that of fluorescein but its fluorescent intensity compared to fluorescein varies considerably depending on the wavelength employed for excitation. Several hours after oral or intravenous administration the conjugate can become the dominant fluorophore in the plasma. When fluorescein is administered systemically and fluorescent intensity is measured in the eye, it is necessary to determine which compound is being measured since the time courses of the plasma concentrations and the permeability of the ocular barrier of each compound may not be the same. A technique suitable for measuring the relative concentration of each fluorophore in ocular tissues in vivo is suggested.
The Beck and Exner systems of assigning Rorschach form quality were compared, There are some inherent differences in the form quality tables of these two Rorschach systematizers. The Beck system is more extensive and seems slightly biased toward-or "poor" form quality in comparison to the Exner system. When the Rorschach records of psychiatric patients were scored for form quality, the Beck system yielded a significantly lower Extended F+% than the Exner system. This effect is probably related to the inherent differences in the respective form quality tables which resulted from the different procedures used in deriving these listings of form quality.
The speech-sound production of severely language-impaired children was monitored in a longitudinal study. In order to generalize findings, acoustical, phonemic, and clinical observation data were collected from 30 children. Results showed that speech-sound acquisition goes through a hierarchical sequence of development and that speech-sound production will deteriorate in a predictable manner depending on the pathology. The authors hypothesize a speech-sound acquisition model, SSAM, based on the development observed.
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In Canada, the forest industry has the highest rate of lost time injury (161 per thousand workers in 1986) and has the highest fatality rate (1.04 per thousand workers in 1986) of all industries. A retrospective case series of fatal accidents occurring among those employed as fallers or buckers in the British Columbia Forest Industry was studied. 87 cases were found and the files of the provincial coroner were accessed to provide data on these accidents. Due to a lack of denominator data, no risk factors could be identified by several hypotheses for future research were developed. These included: the possibility that lack of work experience and young age may play a role in these accidents, the observation that there are "peaks of incidence" just before noon, on Mondays and Thursdays and in January. There was also the surprising finding of the lack of toxicological evidence indicating impairment of any of these workers. Future directions for research are discussed.