Petrol sniffer's encephalopathy and lead exposure.
Explore the source record for details and available documents.
Central Nervous System Diseases↗
Biomedical subjects
C B Burns
Publications and source records attributed to C B Burns.
Elevated serum creatine kinase (CK-MM) in petrol sniffers using leaded or unleaded fuel.
This study examined blood lead and creatine kinase levels in a group of 24 Australian Aboriginal males admitted to the hospital for treatment of severe petrol sniffing related illness after using only leaded petrol and 27 sniffers, 16 ex-sniffers and 13 non-sniffers from an isolated Aboriginal community using only unleaded petrol. Creatine kinase levels (which were nearly all creatine kinase-skeletal muscle isoenzyme indicating skeletal muscle damage) were correlated with blood lead levels and were elevated in active sniffers of leaded petrol on admission to hospital but were also increased in those sniffing unleaded petrol in the remote community. After fourteen days in hospital, median creatine kinase levels of leaded petrol sniffers dropped rapidly to levels similar to those of ex-sniffers and non-sniffers while median blood lead levels decreased but still remained higher than the other three groups. The data suggest that elevated creatine kinase associated with petrol sniffing may be due to compounds in petrol other than the lead additives, possibly volatile hydrocarbon components. Elevated creatine kinase may be useful in detecting current petrol sniffing activity, particularly in locations using unleaded petrol.
Adolescent↗
Effect of knee angle and ligament insufficiency on anterior tibial translation during quadriceps muscle contraction: a preliminary report.
Additional information is needed regarding the effects of exercise protocols on the injured or reconstructed anterior cruciate ligament (ACL). The purpose of this investigation was to assess the effects of knee flexion angle and ACL insufficiency on anterior tibial translation (ATT) and patellar ligament insertion angle as subjects performed maximal isometric quadriceps muscle contractions. The subjects were two females and two males between the ages of 18 and 24 who had sustained injuries that resulted in unilateral ACL insufficiency. Each subject performed maximum isometric quadriceps muscle contractions with each leg on a Cybex II dynamometer at each of three positions: 15, 45, and 75 degrees knee flexion. A lateral knee roentgenogram was obtained as each subject maintained each isometric muscle contraction. A roentgenogram also was taken as subjects rested each knee in each of the three target positions. Anterior tibial translation for each isometric muscle contraction was assessed by measuring the anterior displacement of the tibial plateau on the isometric resisted roentgenogram relative to the resting roentgenogram. Patellar ligament insertion angle also was measured for each roentgenogram. Maximum ATT occurred at the 15 degrees knee flexion target angle for two subjects and at the 45 degrees target angle for the other two subjects. Patellar ligament insertion angle decreased as knee flexion angle increased. Appreciable stress may be imposed on the ACL as patients perform maximum quadriceps muscle contractions in positions of terminal knee extension and in midrange positions previously reported as being safe for maximal effort quadriceps exercise. Magnitude of stress imposed on the ACL is discussed as a function of the length-tension relationship of the quadriceps muscle-tendon unit and insertion angle of the patellar ligament. Suggestions are made for additional research regarding appropriate muscle strengthening protocols for patients who have undergone ACL reconstruction.
Adolescent↗
A comparison of the effects of inorganic and alkyllead compounds on human erythrocytic delta-aminolevulinic acid dehydratase (ALAD) activity in vitro.
A study comprising two experiments comparing the effects of the alkyllead compounds triethyllead acetate and tetraethyllead as well as an inorganic lead compound (Pb(NO3)2) on human erythrocytic delta-aminolevulinic acid dehydratase activity was undertaken. In Experiment 1, four human blood samples were pre-incubated for 0 min or 60 min with increasing concentrations (0-1000 microM) of triethyllead acetate, tetraethyllead and Pb(NO3)2, and the delta-aminolevulinic acid dehydratase activity was determined. There was no discernible inhibitory effect of tetraethyllead at any concentration, with or without pre-incubation. Pb(NO3)2 showed a distinct effect at an addition concentration of 1 microM, with a substantial inhibition only following pre-incubation. Triethyllead acetate showed no difference in effect with pre-incubation. In the second experiment, the activating effects of zinc chloride (60 microM) and dithiothreitol (20 mM) on delta-aminolevulinic acid dehydratase activity were examined on four human blood samples in the presence of varying concentrations of Pb(NO3)2 (0-50 microM) and triethyllead acetate (0-1000 microM). The addition of zinc chloride alone showed little effect on enzyme activity, while dithiothreitol alone caused a substantial activation of the enzyme at all lead concentrations. The addition of both zinc chloride and dithiothreitol caused an even greater activation of the enzyme. The data indicate that Pb(NO3)2 is a much more potent inhibitor of delta-aminolevulinic acid dehydratase activity than triethyllead acetate (Ki values of 0.77 microM versus 130.37 microM. respectively). The use of delta-aminolevulinic acid dehydratase activity as an indicator of exposure may be questionable in cases of alkyllead exposure. Possible causes for differences in the inhibition of delta-aminolevulinic acid dehydratase by these compounds is also discussed.
Erythrocytes↗
Effects of deep inhalation in asthma: relative airway and parenchymal hysteresis.
Asthmatic subjects were screened for the effects or volume history on the degree of induced airway obstruction with methacholine by comparing isovolumic maximal expiratory flows (Vmax) from partial expiratory flow-volume curves (P) begun near functional residual capacity (FRC) followed by maximal expiratory flow-volume (M) maneuvers begun from total lung capacity (TLC). The isovolumic Vmax values from M and P maneuvers defined two groups: one had a high M/P ratio (high group), indicating a large degree of reversal with deep inhalation, another had a low M/P ratio (low group), indicating minimal reversal. No differences were found between groups. A more complete study was later performed in which we measured specific airway conductance (sGaw) and anatomical dead space (VD) as indices of airway size and hysteresis before and after deep inhalation. The area of quasi-static transpulmonary pressure (Ptp) volume (V) curves from FRC to TLC and back to FRC was measured as an index of parenchymal hysteresis. At base line both groups showed a decrease in both sGaw and VD after a deep inhalation (DI). After constriction neither group changed VD after DI, whereas sGaw increased significantly in the high group after DI. This suggests that dilation of airways with DI occurred peripheral to those contributing to VD in the high group. The areas of the Ptp-V curves were equal at base line; yet the increase in areas with constriction in the low group was much greater.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Prenatal diagnosis of a severe deforming type of osteogenesis imperfecta.
A pregnancy at risk for a severe deforming type of osteogenesis imperfecta (OI) was monitored by ultrasonography and radiography. Long bone measurements were normal at 15 1/2 weeks gestation, but ultrasound detected an abnormality of one femur that appeared to be a fracture. The ultrasound study at 19 weeks revealed severe shortness of the femora, and radiographs showed only vertebral bodies with no other fetal skeletal parts clearly visible. These studies indicate the feasibility of prenatal diagnosis before 20 weeks for the more severe handicapping types of OI that are compatible with survival past the newborn period and that can result in death during later infancy.
Female↗
Evaluation of single-breath helium dilution total lung capacity in obstructive lung disease.
We examined the effect of obstructive lung disease on the single-breath helium dilution method of measuring total lung capacity (TLC). In test results of 79 patients, we found this dilution method underestimated the TLC determined by a radiographic method by a mean of 2.3% in normal subjects, 10.4% in patients with mild, 21.8% in those with moderate, and 38.0% in those with severe obstruction. The ratio of forced expiratory volume in one second to forced vital capacity was used to group the patients; the differences in the degree of underestimation of TLC between groups were significant (p less than 0.05). In addition, we found a strong correlation between the degree of underestimation of TLC by the helium method and the severity of obstruction when patients were considered as a continuous population. Using a regression equation based on this correlation, we derived a method for correcting the helium dilution TLC. This allows use of this test in patients whose obstructive disease would otherwise render it inaccurate.
Adult↗
Hypoxemia during hemodialysis.
Explore the source record for details and available documents.
Acetates↗
Method for preserving erythrocytic delta-aminolevulinic acid dehydratase activity that facilitates population studies on lead intoxication.
A method preserving the activity of the erythrocytic enzyme delta-aminolevulinic acid dehydratase (EC 4.2.1.24) was developed using a vehicle of 50% aqueous glycerol containing dithiothreitol (80 microM). Whole heparinized blood (0.5 ml) was added to 0.75 ml of this mixture in a cryovial tube (capacity 1.3 ml), mixed well and stored in a freezer at -20 degrees C for 21 days. Statistical comparison of the enzyme activity when freshly assayed and after storage indicated excellent agreement for quantitation of the non-activated enzyme (intraclass correlation coefficient = 0.99) and the activated enzyme (intraclass correlation coefficient = 0.98). This storage method will facilitate future population studies on lead intoxication, particularly those in remote locations.
Erythrocytes↗
Niobium/aluminum filters reduce patient exposure.
Reducing patient exposure while maintaining image quality is key to radiographers. In a comparison study of different filters, the authors found that a combined niobium/aluminum filter provides substantial reduction of entrance skin exposure with fairly small increases in tube loading and little loss of image contrast.
Aluminum↗
Advantages of a 400 speed image receptor system for cast radiography.
By using a faster intensifying screen as opposed to the traditional extremity system for cast radiography, one can reduce the dose to the patient significantly while maintaining quality cast radiographs. In this study a 400 speed Lanex Regular, TMG film system was compared to a 100 speed Lanex Fine, TMG film system. The findings suggest that slow speed, high resolution systems are unnecessary for cast radiography. Evidence demonstrated reduced patient exposure and suggested decreased motion and increased tube life as a result of shorter exposures.
Casts, Surgical↗
Using the same exposure factors for wet and dry casts.
This article presents laboratory and clinical findings that suggest the exposure factors for wet and dry casts should be the same and the selection of factors should be based on cast thickness rather than water content.
Calcium Sulfate↗
Erect positions for "tunnel" views of the knee.
Two erect methods of radiographing the knee to produce tunnel views of the joint space are presented. Each method produces an excellent image of the intercondyloid fossa without distortion seen with some previous methods. Both erect methods are simple to perform and appear to be more comfortable for patients.
Humans↗
The effect of decreased developer activity on patient exposure.
Overexposing and underdeveloping a radiographic image is not a common practice, but it has been observed to occur as a result of poor processing protocols. This study discovered that, as a result of decreased developer activity, the patient exposure could be three times as great as it would be under normal conditions.
Radiation Dosage↗
Erect position/tangential projection of the patellofemoral joint.
This paper presents an erect position, using 40 degrees knee flexion and a vertical central ray, as a simple alternative to help overcome the problems encountered with the standard "sunrise" view of the patella and patellofemoral joint.
Humans↗
Molybdenum/aluminum filters perform effectively.
In this study, the performances of stacked niobium/aluminum and molybdenum/aluminum filters were compared to that of a standard 2.5 mm aluminum filter. The molybdenum/aluminum filter had the same performance characteristics as the niobium/aluminum filter but was less expensive. The study results show that the molybdenum/aluminum filter should be a good filter choice for facilities embracing ALARA principles.
Aluminum↗