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Biomedical subjects

J Mathews

Publications and source records attributed to J Mathews.

At least 55 records · Page 3Linked to original sources
PubMed1994

Intravenous access in the critically ill trauma patient: a multicentered, prospective, randomized trial of saphenous cutdown and percutaneous femoral access.

STUDY OBJECTIVE: To compare the speed of IV access and the rate of infusion for saphenous venous cutdown and percutaneous femoral catheterization. DESIGN: Prospective, randomized, multicentered trial. Patient enrollment occurred from September 1990 through September 1991. SETTING: Patients were enrolled at three urban Level I trauma centers. TYPE OF PARTICIPANTS: Seventy-eight critically ill trauma patients. INTERVENTIONS: Participants were randomized to one of two groups: saphenous cutdown or percutaneous femoral line. After successful cannulation of the vein, 1 L of crystalloid was infused by gravity. RESULTS: The mean procedure time for the cutdown group was 5.63 +/- 2.58 minutes compared with 3.18 +/- 1.19 minutes for the femoral line group (P < .0001). The mean infusion time for the cutdown group was 6.65 +/- 4.29 minutes compared with 4.56 +/- 2.47 minutes for the femoral line group (P < .03). The mean overall time for the cutdown group was 11.76 +/- 4.81 minutes compared with 7.67 +/- 2.78 minutes for the femoral line group (P < .0002). CONCLUSION: Percutaneous femoral catheterization can be performed more rapidly than saphenous cutdown in the critically ill trauma patient with a palpable femoral pulse and allows for more rapid fluid administration. We support the use of a percutaneous femoral line as an acceptable alternative to saphenous venous cutdown in the initial resuscitation of trauma patients.

Adult↗
PubMed1994

Streptokinase alleles and disease association in group A streptococci.

Allele-specific oligonucleotides were used for PCR-based typing of the streptokinase locus of group A streptococcal strains, including well characterized type strains, isolates from patients with acute poststreptococcal glomerulonephritis and strains from Aboriginal communities in the Northern Territory of Australia. The streptokinase SKN allele, previously thought to be associated with glomerulonephritis, was no more frequent in nephritogenic than in non-nephritogenic streptococcal strains in this collection.

Alleles↗
PubMed1992

Current serum levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin in phenoxy acid herbicide applicators and characterization of historical levels.

BACKGROUND: Workers who sprayed phenoxy acid herbicides, especially those who sprayed before 1975, may have been exposed to significant amounts of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent animal carcinogen present in herbicide preparations as a contaminant. PURPOSE: The aims of this study were (a) to determine serum levels of TCDD in a representative sample of workers occupationally exposed to the agent during the spraying of phenoxy acid herbicides; (b) to compare serum levels in workers exposed before 1965, when concentrations in herbicide products were unregulated and high, with levels in workers exposed after 1974, when concentrations were lower as a result of government regulations worldwide; and (c) to examine the correlation, if any, between serum levels and duration of employment in spraying. METHODS: Thirty-seven subjects were randomly selected from a group of 654 men who had sprayed the herbicides 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) in Australia for at least 12 months. The workers were classified as follows: eight who sprayed only before 1965, nine who sprayed only during the period after 1964 and before 1975, and 20 who sprayed during the period after 1974 and before 1991. Serum from the workers was analyzed for TCDD by high-resolution gas chromatography and high-resolution mass spectrometry at a detection limit of 0.6 parts per trillion (ppt) on a lipid-weight basis. In addition, rates of exposure to TCDD were estimated, as were TCDD serum concentrations at termination of employment and intensity of herbicide use. RESULTS: Only one worker, with a serum TCDD level of 34 ppt, had a serum level higher than the maximum level of 26 ppt reported for the general population. Assuming a half-life of 7.1 years, we estimated the mean exposure rates to be 2.7, 2.3, and 0.06 ppt/mo for the three epochs, respectively. We found the highest serum level of TCDD at the time of cessation of employment to be 329 ppt. Calendar period and intensity of use of 2,4,5-T and 2,4-D were statistically significant determinants of rate of exposure to TCDD, but 2,4-D was associated with exposure rate only for the pre-1975 periods. Estimated rates prior to 1965 were more than an order of magnitude higher than those after 1974. CONCLUSION: The highest estimated exposure rate was 20.7 ppt/mo, which suggests that some sprayers may have been exposed to levels comparable with those that produce cancer in laboratory animals.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1992

Rheumatoid arthritis in twins: a study of aetiopathogenesis based on the Australian Twin Registry.

The 1980 cohort of the Australian Twin Registry contains 3808 pairs of twins, 258 of whom self reported a diagnosis of rheumatoid arthritis (RA) in one or both subjects. Seventy two pairs were lost to follow up by 1990. The remaining 186 pairs received a self administered questionnaire, followed, if necessary, by telephone interviews to them, their general practitioners, and their specialists. Twenty discordant and three concordant pairs of twins were verified as having RA. The prevalence of RA in this sample was 0.40%. There was an 89% false positive rate for the self reported diagnosis of RA. Pairwise concordance percentages for RA were as follows: monozygotic 21% (95% confidence interval (CI) = 6 to 44), dizygotic 0% (95% CI = 0 to 25). It was concluded that: (a) there is a high false positive rate in self reporting RA; (b) the prevalence of RA in Australia may be less than the 0.8-1.0% often quoted; and (c) genetic factors play some part in the aetiopathogenesis of RA but do not account entirely for its determination.

Adolescent↗
PubMed1991

Daily administration of the progesterone antagonist RU 486 prevents implantation in the cycling guinea pig.

Since progesterone is required to prepare the endometrium for implantation of an embryo, a progesterone antagonist may inhibit nidation and thus prevent pregnancy. We addressed this possibility in the guinea pig, the small laboratory animal whose reproductive physiology most resembles that of women. Daily administration of the antiprogestin RU 486 (0, 1, 2, or 3 mg/kg, subcutaneously) for 9 days after mating inhibited implantation in a dose-dependent fashion. When this compound was given daily throughout the estrous cycle, cyclic vaginal changes, ovulation, and mating were suppressed in up to 17%, 28%, and 55% of animals, respectively. Two of seven mated female animals receiving RU 486, 1 mg/kg/day, had implantation sites. Nidation was completely blocked at higher doses. Thus daily antiprogestin administration prevented pregnancy in sexually active, normally cycling guinea pigs. A similar strategy using a daily antinidatory dose of an antiprogestin may offer a novel approach to human fertility control.

Animals↗
PubMed1990

Sodium-22 influx into erythrocytes from diabetic hypertensive patients on maintenance hemodialysis.

We have studied the percentage of 22Na+ uptake in cell suspensions; 0.4 to 2.0 x 10(9) erythrocytes/mL from diabetic uremic patients with secondary hypertension and from normal subjects. Suspensions from diabetic uremic patients with secondary hypertension 0.42 +/- 0.06 to 2.05 +/- 0.28; normal subjects showed a percentage uptake of 22Na+ of 0.27 +/- 0.05 to 1.28 +/- 0.22. The uptake of 22Na+ in 2.0 x 10(9) cells/mL was 60% more (P less than .05) in diabetic uremic patients than in the controls. These studies indicate that 22Na+ influx determinations may be used to distinguish secondary hypertensive patients from normal subjects.

Adult↗
PubMed1989

A follow-up report of occupational stress in urban EMT-paramedics.

A survey completed by 280 nonvolunteer, urban emergency medicine technician (EMT)-paramedics revealed high levels of occupational stress. We used a four-component model of occupational stress in medical environments to show indications that much variation in the manifestation of stress was accounted for by the rank and job description of the EMT-paramedic, the district served by the EMT-paramedic, and the patient population served by the EMT-paramedic. Stress exhibited by field EMT-paramedics tended to manifest in more negative attitudes toward patients, whereas administrative-level paramedics exhibited more organizational stress. We noted that the age of the EMT-paramedic and the length of time employed as an EMT-paramedic correlated with the level of occupational stress (P less than .05). The recent occurrence of significant life events also was significantly related to the level of stress (P less than .05). An EMT-paramedic's gender, marital status, and number of calls per shift had no significant correlation to the level of occupational stress. Based on these results, we recommend tailoring occupational stress programs to meet the needs of individual EMT-paramedics. Special attempts should be made to identify and counsel EMT-paramedics who are undergoing stressful life events. Finally, we suggest that rotating EMT-paramedics through various districts on a regular basis may help alleviate the negative impact on patient care in areas that have been identified as particularly stressful. Further studies are needed to verify our hypothesis.

Administrative Personnel↗
PubMed1988

A simpler procedure to study sodium-22 uptake (ouabain insensitive) in human erythrocytes.

We report a modification of the technique of Mahoney et al. (Blood 1982; 59: 439) for the determination of sodium-22 (22Na+) uptake in human erythrocytes. This modification facilitates the separation of 22Na+ taken up by erythrocytes from the free 22Na+ in the buffer by the addition of dibutyl phthalate, which forms an immiscible layer between the two. To further improve the sensitivity of 22Na+ uptake, we incubated a range of known numbers of erythrocytes with 22Na+ as opposed to the single cell suspension of known hematocrit used in Mahoney's et al. procedure (1). Erythrocytes are incubated in KCI buffer containing 2627 Bq (0.071 microCi) 22Na+ in a total volume of 0.5 mL for 0.5 h at 37 degrees C. Incubation is terminated by placing the tubes in ice for 10 min and the amount of 22Na+ taken up by the erythrocytes determined. We observe a linear relationship between erythrocyte concentrations (0.5 to 2.5 X 10(9) cells/mL) and percent uptake of 22Na+ (0.37 +/- 0.06 (1 SD) to 1.85 +/- 0.27 (1 SD) of the total 22Na+, respectively). The procedure is simple and sensitive, and can be used in clinical laboratories for the routine evaluation of 22Na+ uptake in erythrocytes.

Black People↗
PubMed1988

The use of epinephrine in the treatment of older adult asthmatics.

Three subcutaneous doses of 0.3 mL 1:1,000 epinephrine were given 20 minutes apart to 95 adult asthmatics 15 to 96 years old during 108 asthma exacerbations. Patients with a history of recent myocardial infarction or of angina were excluded from our study. Heart rhythm and rate, blood pressure, respiratory rate, and clinical response were prospectively evaluated before, during, and after the administration of epinephrine. There was no significant difference in the occurrence of ventricular arrhythmias between patients less than 40 and more than 40 years old. The mean systolic and diastolic blood pressures, mean heart rate, and mean respiratory rate decreased with treatment in the older population. Our results suggest that epinephrine is safe to use in acute asthmatics of any age.

Acute Disease↗