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Biomedical subjects

A Burke

Publications and source records attributed to A Burke.

85 records · Page 5Linked to original sources
PubMed1978

X-ray fluorescence analysis of lead in teeth of urban children in situ: correlation between the tooth lead level and the concentration of blood lead and free erythroporphyrins.

The tooth lead level of 30 lead-exposed children was measured in situ using an X-ray fluorescence technique. The tooth lead concentration divided by the child's age correlated with the free erythroporphyrin (FEP) (r = 0.51) and the blood lead levels (r = 0.31). The mean tooth lead concentrations of 10 Class IV children (FEP greater than or equal to 190 micrograms/100 ml; blood lead 30-80 micrograms/ml) was 14.5 +/- 5.5 ppm/year. Reexamination of the histories of children who had been classified as Class II or III, but who had tooth lead concentrations within 1 SD of the Class IV level, indicated that many of these children could also be considered to be Class IV children. When the x-ray fluorescence technique was used to screen an urban population of 300 children, the tooth lead values indicated that 72% of the children had been exposed to low levels of environmental lead. Six percent of the children were found to have tooth lead concentrations in excess of 9 ppm/year and within 1 SD of the mean value exhibited by Class IV children. These children were considered to have a high body lead burden. The percentage of children having an elevated tooth lead level is similar to the number previously reported using exfoliated deciduous teeth.

Child↗
PubMed1976

Heterogeneity of chondrocyte mitochondria. A study of the Ca2+ concentration and density banding characteristics of normal and rachitic cartilage.

Previous morphological studies of the mineralizing epiphysis suggested that some mitochondria were concerned with Ca2+ accumulation while others were associated with cellular energetics and metabolism. To determine if there was mitochondrial heterogeneity in chondrocytes of the epiphyseal growth plate, mitochondria were isolated from four different regions of the plate and subjected to continuous sucrose gradient centrifugation. Centrifugation of the organelles in a narrow density sucrose gradient (1.5--2.0 M) in the presence of inhibitors of Ca2+ transport (ruthenium red and 5,5'-dithiobis-(2-nitrobenzoic acid)) revealed that considerable heterogeneity existed. In the least calcified zone 20% of the mitochondria formed a low density band of low Ca2+ concentration (309 nmol/mg protein). Organelles isolated from more calcified tissue zones showed a concomitant increase in Ca2+ concentration (up to 5700 nmol/mg protein) as well as an increase in the total percentage of mitochondria sedimenting in 2.0 M sucrose. The banding patterns of mitochondria isolated from rachitic and hypertrophic cartilage were similar. In addition, similarities were also noted in the Ca2+ concentration and the cytochrome oxidase activities of mitochondria of these tissues. During recovery from the rachitic condition, there was a change in the density centrifugation characteristics of this tissue and a substantial increase was noted in the proportion of mitochondria sedimenting in 2.0 M sucrose. The Ca2+ concentration of mitochondria of this rapidly calcifying tissue suggested that the critical Ca2+ concentration necessary for initiation of the calcification mechanism was 4 mumol/mg protein.

Animals↗
PubMedDate not supplied

Bipolar scissors in facial plastic surgery.

BACKGROUND: Many methods are available to the facial plastic surgeon for elevating and separating tissue, from cold steel to monopolar cautery to various laser-cutting technologies. Bipolar cautery has replaced monopolar cautery as the optimal hemostatic technique because of its decreased tissue damage and improved capabilities. Bipolar scissors concurrently offer a dissecting technique with hemostatic capability. Little exists in the otolaryngology literature on the use of bipolar scissors for soft tissue dissection. OBJECTIVE: To describe our experience using bipolar scissors in a variety of facial plastic and reconstructive procedures. SETTING: Tertiary care referral academic center. DESIGN: We retrospectively reviewed 78 procedures performed using bipolar scissors between June 1997 and August 1999. In facial plastic cosmetic surgery, bipolar scissors were used 31 times for deep plane face-lifts and 16 times for endoscopic browlifts. In facial plastic reconstructive surgery, bipolar scissors were used in 15 radial forearm free flaps, 10 fibula osteocutaneous flaps, 3 rectus abdominis free flaps, and 3 latissimus dorsi myocutaneous free flaps. RESULTS: In all procedures, bipolar scissors facilitated the dissection. By allowing for a drier field, less time was required to elevate the flap and obtain hemostasis. Complications were not increased compared with historical controls. In the harvesting of fibula osteocutaneous free flaps, use of bipolar scissors allowed harvesting without use of a tourniquet. CONCLUSION: Bipolar scissors, a new technology in facial plastic surgery, allow the same control as sharp dissection and provide simultaneous hemostasis.

Dissection↗
PubMedDate not supplied

Situs inversus totalis and single coronary ostium: A coincidence or a pattern?

Situs inversus totalis and single coronary ostium are rare congenital anomalies, and no ontogenic connection has been described between them. Only three cases of association of single coronary ostium and situs inversus have been reported in the literature, all found on angiography. Here we present the first case of this association discovered at autopsy. Based on the apparently higher than expected frequency of this finding, an underlying pathologic connection between these conditions is proposed.

Adult↗
PubMedDate not supplied

Low-level lead exposure in childhood influences neuropsychological performance.

Cumulative lead exposure in 193 inner-city black children was assessed by measuring lead concentrations in the primary and circumpulpal dentine of their deciduous teeth. Lead concentrations for these children were comparable to the concentrations reported in population studies of low-income children living in inner-city areas. Analysis of the children's neuropsychological test performance showed that elevated lead levels were associated with deficits in visual-motor functioning and perceptual integration, right-left orientation, and verbal abstraction; other verbal abilities and motor functioning were not affected. Possible alternative explanations for these findings were evaluated by examining the relationships between lead and maternal intelligence, family socioeconomic status, and perinatal indicators of neurological impairment. None of these relationships was significant. It was concluded that, even at levels usually regarded as asymptomatic, lead in the environment represents a hazard to inner-city children.

Adolescent↗