Search PubMed⌕ Search

Biomedical subjects

R L Smith

Publications and source records attributed to R L Smith.

At least 739 records · Page 41Linked to original sources
PubMedDate not supplied

A death education curriculum for emergency physicians, paramedics, and other emergency personnel.

Although death education is a standard component in most medical schools and nursing programs, few include instruction on dealing with sudden death. Typically, death education courses overlook instruction in areas germane to emergency medicine, e.g., making death notifications, interacting with survivors during the immediate grief period, and reducing professional stress innate to working with newly bereaved persons. This curriculum was developed to address the paucity of existing death education materials for emergency professionals. Topics include death perspectives and awareness, death typology, cultural and religious considerations, communicating with bereaved persons, making death notifications, and dealing with initial grief reactions. Units of instruction are outlined, including educational goals, descriptions of units, teaching strategies, and supplemental readings.

Adaptation, Psychological↗
PubMedDate not supplied

The subchronic oral toxicity of ethane, 1,2-bis(pentabromophenyl) (Saytex 8010) in rats.

Ethane, 1,2-bis(pentabromophenyl) (EBP; CAS no. 8452-53-9) dose levels of 0, 100, 320 and 1000 mg/kg/day administered to rats by gavage in corn oil for 90 consecutive days produced no compound-related clinical signs of systemic toxicity, ocular lesions, or alterations in urinalysis, clinical chemistry, and hematology values in the treated or recovery groups. No biologically or toxicologically significant differences were observed in body weights, body weight gains, and food consumption. Statistically significant differences were found between control and high-dose animals in mean absolute or relative liver weights. Histomorphological evaluation showed in male rats low-grade liver changes consisting of minimal to slight hepatocellular vacuolation (high-dose males) and minimal to slight centrilobular hepatocytomegaly (high- and possibly mid-dose males). These changes had resolved by the end of the 28-day recovery period. No treatment-related changes were found in the livers of female rats. No treatment-related histomorphologic changes were present in any of the other tissues examined in either sex, except for evidence of aspirated test article in individual rats. The 90-day EBP no-adverse-effect level in the rat was > or = 1000 mg/kg/day, and was consistent with that of the preceding 28-day study (no-effect level > or = 1250 mg/kg/day). EBP's lack of toxicity is likely related to poor bioavailability due to its high molecular weight and low solubility.

Administration, Oral↗
PubMedDate not supplied

Itraconazole responsive tinea capitis in an HIV-infected child.

Tinea capitis has not been reported to be a prevalent or serious affliction in pediatric patients infected with the human immunodeficiency virus (HIV). We report tinea capitis due to Microsporum canis in a boy infected with HIV. After failing conventional therapy, he was treated successfully with a four-week course of itraconazole. His immunologic status improved during therapy. The possible relationship of this response to the ultimate resolution of disease is discussed.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Oxidation phenotyping in alcoholics with liver disease of varying severity.

The propensity to develop alcoholic cirrhosis is probably, at least in part, genetically determined. A striking similarity exists histologically between perhexiline and alcohol-related hepatitis and both are potentially precirrhotic lesions. Liver damage due to perhexiline is associated with impaired drug oxidation capacity which is genetically determined and tested by use of debrisoquine. Oxidation phenotyping might be used to predict susceptibility to perhexiline liver damage; it might also predict the potential to develop alcoholic cirrhosis. Oxidation phenotyping was therefore undertaken, using debrisoquine in 100 alcoholic patients, 30 of whom had only fatty liver despite prolonged alcohol abuse, while the remaining 70 had alcoholic hepatitis and/or cirrhosis. One hundred patients with nonalcoholic chronic liver disease served as controls. The number of patients with severely impaired drug oxidation capacity (poor metabolizer phenotype) was similar in the alcoholic group (8%) and the nonalcoholic control group (7%). In particular, the incidence of the poor metabolizer phenotype was similar in alcoholics with severe liver disease (10%) and in those with only fatty change (3%). There appears to be no association between the susceptibility to develop alcoholic cirrhosis and drug oxidizing capacity.

Adult↗
PubMedDate not supplied

Cochlear processes reflected in responses of the cochlear nerve.

The effects of sound frequency, intensity, and duration on responses of cochlear-nerve fibers and inner hair cells (IHCs) are reviewed and compared. The frequency selectivity observed in the nerve is already present in the IHC receptor potential but synaptic transmission appears to influence some other properties of the nerve response. First, the average rate-intensity function of a nerve fiber spans a smaller operating range than the IHC input-output characteristic. However, nerve fibers with different sensitivities can innervate the same IHC and respond over different regions of its characteristic. Second, adaptation is present in the nerve-fiber response but not observed in the IHC. It appears to result from a decrease in synaptic transmission and produces temporal contrast and a decrease in operating range. Interactions among the various effects have important influences on the spatiotemporal pattern of cochlear-nerve responses to complex stimuli.

Acoustic Stimulation↗
PubMedDate not supplied

Lysosomal enzyme production at the interface surrounding loose and well-fixed cemented tibial hemiarthroplasties in the rabbit knee.

Fourteen mature New Zealand white female rabbits had a right, cemented, tibial hemiarthroplasty using a stemmed, fluted, titanium alloy, condylar-type prosthesis. In one group (seven rabbits), polymethyl methacrylate (PMMA) was used to cement the prosthesis firmly. In a second group (seven rabbits), the prosthesis was treated with cement ex vivo; the prosthesis and cured cement were then implanted, and rotated once within the bone to ensure that the prosthesis was loose fitting. Roentgenograms performed postoperatively and at 3 months were graded for new (i.e., not present on the immediate postoperative radiograph) radiolucent lines. At 3 months, the tissue adjacent to the implant was harvested sterilely and cultured over a 3-day period; the tissues and culture supernatants were then assayed for total protein, DNA content, and lysosomal enzyme activity (N-acetyl-beta-D-glucosaminidase and beta-glucuronidase). The mean cumulative grading of new lucent lines was 0.4 +/- 0.3 (mean +/- standard error) for the well-fixed prosthetic group and 2.0 +/- 0.6 for the loose prosthetic group. The tissue surrounding loose prostheses contained more DNA and total protein, and produced greater amounts of lysosomal enzymes compared to well-fixed prostheses. The control left sides were not statistically different for any parameter analyzed. The increased DNA content demonstrates an increase in cellularity of the tissue surrounding loose prostheses. Normalization of the relative amount of enzyme released as a function of cellularity (DNA) suggests that the influx of cells into the area surrounding loose prostheses may be more important to the overall increase in lysosomal enzyme release than increased production of lysosomal enzymes by individual cells.

Acetylglucosaminidase↗
PubMedDate not supplied

Designing healthcare regions: a Canadian approach.

Regionalizing healthcare delivery is a means to control rising costs and improve service delivery. The authors reviewed current and proposed healthcare regionalization models across Canada, and summarized their findings regarding several key factors. Their research on regionalization has led them to develop guidelines directed at those involved in planning and implementing healthcare regionalization.

Canada↗
PubMedDate not supplied

Time-dependent effects of intermittent hydrostatic pressure on articular chondrocyte type II collagen and aggrecan mRNA expression.

The normal loading of joints during daily activities causes the articular cartilage to be exposed to high levels of intermittent hydrostatic pressure. This study quantified effects of intermittent hydrostatic pressure on expression of mRNA for important extracellular matrix constituents. Normal adult bovine articular chondrocytes were isolated and tested in primary culture, either as high-density monolayers or formed aggregates. Loaded cells were exposed to 10 MPa of intermittent hydrostatic pressure at a frequency of 1 Hz for periods of 2, 4, 8, 12, and 24 hrs. Other cells were intermittently loaded for a period of 4 hrs per day for 4 days. Semiquantitative reverse transcription polymerase chain reaction assays were used to assess mRNA signal levels for collagen types II and I and aggrecan. The results showed that type II collagen mRNA signal levels exhibited a biphasic pattern, with an initial increase of approximately five-fold at 4 and 8 hrs that subsequently decreased by 24 hrs. In contrast, aggrecan mRNA signal increased progressively up to three-fold throughout the loading period. Changing the loading profile to 4 hrs per day for 4 days increased the mRNA signal levels for type II collagen nine-fold and for aggrecan twenty-fold when compared to unloaded cultures. These data suggest that specific mechanical loading protocols may be required to optimally promote repair and regeneration of diseased joints.

Aggrecans↗
PubMedDate not supplied

Determination of gold in animal tissue by graphite furnace atomic absorption spectrophotometry.

Historically, compounds that contain gold have been used to treat conditions such as rheumatoid arthritis in humans. However, understanding of the metabolic fate of gold in biological tissues has been limited by lack of sensitive quantitative methods of analysis. We addressed this problem by developing a graphite furnace atomic absorption (GFAA) spectrophotometric method to measure trace amounts of gold. This method was validated on small samples of beef liver, kidney, and bone. The samples were digested in micro-Kjeldahl flasks with a mixture of sulfuric, perchloric, and nitric acids; the residue was treated with aqua regia and extracted into methylisobutyl ketone (MIBK); levels of gold were then measured by GFAA. All the reagents were of an ultra-pure grade and were monitored for gold content. We established that the linear range of quantitation was from 1 to 2500 ppb. Multiple extractions with MIBK were not necessary to recover all the gold, and, in most cases, use of ultra-pure acids was not necessary. A scan of the extracts by inductively coupled argon plasma atomic emission spectrophotometry revealed no appreciable concentration of elements that would be most likely to interfere with the determination of gold. Average recoveries of gold ranged from 102 to 111%, and the overall coefficient of variation was 5.5%.

Animals↗
PubMedDate not supplied

Measurement of trace levels of total aluminum in foods by atomic absorption spectrophotometry.

A graphite furnace atomic absorption spectrophotometry method was used to determine the total aluminum content of various foods found in an average American diet. The food products were ashed in platinum dishes, and the inorganic residue was fused using a sodium carbonate-sodium borate mixture. The fusion step allowed detection of all the various forms of aluminum found in food products. A L'vov platform was used in the graphite furnace to increase the sensitivity of the assay. Care was taken throughout the analysis to avoid various sources of aluminum contamination such as glass and porcelain dishes. All reagents were ultra-pure grade and were continuously monitored for aluminum content. Sodium borate used in the fusion flux mixture had previously been extracted with 8-hydroxyquinoline in chloroform to remove any aluminum present. Both raw and cooked foods were analyzed for aluminum with this method. Average recoveries of aluminum from food products ranged from 84 to 112%. The overall coefficient of variation of this method on the food products tested was 10%.

Aluminum↗
PubMedDate not supplied

Determination of phytosterols in butter samples by using capillary column gas chromatography.

A positive bias in the gas chromatographic (GC) analysis of butter for beta-sitosterol was discovered when attempting to confirm values by gas chromatography/mass spectrometry (GC/MS). The source of the problem was traced to an interfering material that was not effectively separated by packed column GC. Because capillary columns are known to provide superior separation, they were substituted for packed columns in the assay, and instrument parameters were modified accordingly. A compound with a similar retention time, identified by GC/MS as lanosterol, was separated from beta-sitosterol by the capillary column. The capillary column technique was applied to over 300 butter samples. The results indicate that the method can accurately quantitate beta-sitosterol in butter with no known interferences. The limit of detection for this method is 1 mg/100 g. Recoveries at a level of 3 mg/100 g averaged 98% with a coefficient of variation of 3.45%.

Butter↗
PubMedDate not supplied

Evaluation of direct saponification method for determination of cholesterol in meats.

A gas chromatographic (GC) method has been developed for determination of cholesterol in meats. The method involves ethanolic KOH saponification of the sample material, homogeneous-phase toluene extraction of the unsaponifiables, derivatization of cholesterol to its trimethylsilylether, and quantitation by GC-flame ionization detection using 5-alpha-cholestane as internal standard. This direct saponification method is compared with the current AOAC official method for determination of cholesterol in 20 different meat products. The direct saponification method eliminates the need for initial lipid extraction, thus offering a 30% savings in labor, and requires fewer solvents than the AOAC method. It produced comparable or slightly higher cholesterol results than the AOAC method in all meat samples examined. Precision, determined by assaying a turkey meat sample 16 times over 4 days, was excellent (CV = 1.74%). Average recovery of cholesterol added to meat samples was 99.8%.

Chemical Phenomena↗