Search PubMed⌕ Search

Biomedical subjects

D Burnett

Publications and source records attributed to D Burnett.

At least 163 records · Page 9Linked to original sources
PubMed1982

A multicentre european evaluation of the Kodak EKTACHEM GLU/BUN analyzer using NCCLS guidelines and other approaches.

This paper describes the field performance of the Kodak EKTACHEM GLU/BUN Analyzer for glucose and urea. NCCLS protocols PSEP-2, 3 an 4 were used which enable manufacturers to establish performance claims concerning the precision and accuracy of an analytical system. This multicentre trial used four analysers in four European countries, United Kingdom, France, West Germany and Italy to assess within and between laboratory performances. Freeze dried control materials were used for the performance check experiment PSEP-2 and for the replication experiment PSEP-3. The replication study, although very time consuming, was straight forward to undertake and the results were comparable between centres. Compliance with the protocol for comparison of methods experiment PSEP-4 in which laboratories used their own hospital patient samples was more difficult. The problems with obtaining suitable samples and the performance of comparative methods are discussed in detail.

Autoanalysis↗
PubMed1981

An evaluation of four methods for the measurement of elastase activity.

The precision of four different methods for the measurement of low levels of porcine pancreatic elastase was assessed using a synthetic substrate and by three other methods using the natural substrate elastin. The most precise method used the synthetic substrate Succ(Ala)3NA (within-batch coefficient of variation = 1.9%, between-batch coefficient of variation = 2.5%). Fluorescein-labelled elastin was the most precise of those methods using elastin as substrate (within-batch coefficient of variation = 5.1%, between-batch coefficient of variation = 5.5%).

Animals↗
PubMed1981

The kinetics of the urinary excretion of the N-oxide and glucuronides of methaqualone in man.

The urinary excretion of the N-oxide and the glucuronides of five C-monohydroxy metabolites of methaqualone has been studied following the oral administration of a single dose of the drug. The apparent first order rate constants for the excretion of each metabolite (kme) were shown to be numerically smaller than the overall elimination rate constant for methaqualone (k10). The Kme values tended to be greater than or equal to the corresponding apparent first order rate constants for the formation of the metabolite (km) but corresponding kme and km values were always of the same order magnitude. The kme values for the glucuronides were much smaller than the literature kme value for paracetemol glucuronide. The rate of renal elimination of the metabolites was variably sensitive to urine flow but over a period of time of 8 hours or greater the total amount of metabolite recovered in the urine was was independent of the total urine volume.

Adult↗
PubMed1981

Serum and sputum alpha 2 macroglobulin in patients with chronic obstructive airways disease.

Serum alpha 2 macroglobulin concentrations were measured in patients with chronic obstructive airways disease and an age-matched group of control subjects. The mean serum level of alpha 2 macroglobulin was significantly lower in bronchitic subjects with acute chest infections than the mean value of the controls. No significant differences were observed between serum alpha 2 macroglobulin values in controls, subjects with "emphysema", and bronchitic patients who did not have chest infections. Sputum alpha 2 macroglobulin concentrations were compared in sputum samples from bronchitic patients with and without acute chest infections. The protein was detected (greater than 0.2 mg/l) in 94% of sputum samples from infected subjects but only 60% of non-infected sputum samples. Concentrations of alpha 2 macroglobulin in infected samples were significantly higher than the non-infected samples. Sputum/serum concentration ratios of alpha 2 macroglobulin were also significantly higher in infected samples but this difference was eliminated by "correcting" the values with the albumin sputum/serum ratios of the same samples. The results suggest that alpha 2 macroglobulin concentrations are higher in bronchial secretions during chest infection because of increased transudation from the blood rather than the presence of significant local secretion.

Aged↗
PubMed1981

Reversal of possible marrow graft rejection with plasma exchange therapy.

A patient with severe aplastic anemia underwent bone marrow transplantation from her HLA identical sister after a prolonged transfusion history and clinical evidence of shortened red cell and platelet survival. Following the transplant, she exhibited minimal graft vs. host disease which resolved, and was discharged with normal blood counts. Because of falling hemoglobulin, platelets and white blood cell counts 8 weeks following the transplant, graft rejection was suspected. High dose steroid therapy apparently had no effect, since the hematologic parameters continued to fall. She underwent two plasma exchanges, after which all hematologic parameters returned to normal, and she continues to exhibit normal parameters seven months after the transplant. Although other explanations for the reversal of the apparent graft rejection can be considered, the case is presented to call attention to the possibility that plasma exchange, by possibly removing circulating inhibitors of bone marrow function, may be useful and simple method for dealing with graft rejection.

Adult↗
PubMed1981

The immunological measurements of 'free' secretory piece and its relationship to local IgA production.

Free secretory piece (FSP) was studied in the sputum of patients with chronic bronchitis. The concentrations were higher both in the presence of infection and when greater quantities of total secretory piece were present compared to the amount of 11S IgA. A significant inverse correlation was found between the amount of FSP and 11S IgA in the individual samples when standardized for their total secretory piece content (2P less than 0 . 01). This suggests that the amount of FSP in any sample is partly dependent upon the amount of 11S IgA. The techniques employed offer a method for the study of the secretory IgA system in biological fluids. The preliminary results suggest that the secretory IgA system is independent of the systemic IgA system.

Antibody Specificity↗
PubMed1981

Relationship between serum viscosity and intravascular IgA polymer concentration in IgA myeloma.

The relative serum viscosity (RSV) at 37 degrees C was measured at presentation in all 179 patients with IgA myeloma admitted to the IIIrd and IVth British Medical Research Council trials until January 1981. An elevated relative serum viscosity (greater than 1.7) was noted in 83%. Hyperviscosity, as defined by a relative serum viscosity greater than 5, was a comparatively rare presenting feature (5.0%). The relationship between relative serum viscosity and IgA polymer equivalent concentration was examined in 33 of the 179 patients, selected to cover a wide range of serum viscosity. A significant correlation was observed between the two parameters (rs=0.7928, P less than 0.001). The sera from two patients with marked serum hyperviscosity (RSV=9.51 and 9.76) were clearly distinct from this relationship. Protein aggregation appeared to be a major determinant in the development of serum hyperviscosity in these two patients.

Biopolymers↗
PubMed1980

Local IgA production in patients with chronic bronchitis: effect of acute respiratory infection.

The immunoglobulin A and secretory IgA concentrations were studied in the serum and sputum of patients with chronic bronchitis to determine the effect of active chest infection and inflammation upon the estimation of local IgA production. The sputum/serum albumin ratio was higher during chest infection (5.51; SE+/-1.60x10(-2)) than in the non-infected samples (0.75; SE+/-0.14x10(-2);p less than 0.01) suggesting increased transudation as a result of inflammation. There was a similar increase in sputum/serum IgA during infection from 9.47 (SE+/-1.87)x10(-2) to 41.21 (SE+/-6.92)x10(-2)(p less than 0.01). However, the proportion of IgA locally produced when assessed by conventional techniques was unchanged. There was a significant inverse relationship between the estimated local IgA production of the infected samples and the degree of inflammation (r= -0.972;2p less than 0.001) indicating that inflammation was a major determinant of local IgA production. However, the secretory IgA concentrations of the samples were independent of the degree of inflammation. Furthermore, secretory IgA was found in samples that appeared to have failure of local IgA production using the method of Soutar. Clearer information about local IgA production can be obtained by measuring protein components unique to the bronchial secretions rather than applying correction factors to estimate the contribution of serum components, particularly in the presence of inflammation.

Acute Disease↗
PubMed1980

The origin of plasma proteins in human amniotic fluid: the significance of alpha 1-antichymotrypsin complexes.

12 proteins were studied in serum and amniotic fluid from 20 women in late pregnancy by two-dimensional immunoelectrophoresis. A close inverse relationship was observed between the amniotic fluid/serum concentration ratios of 11 proteins and their Stokes radii. These proteins enter the liquor from the maternal blood by molecular filtration. The concentration of alpha 1-antichymotrypsin in amniotic fluid was often higher than expected and the protein was often partially complexed. alpha 1-Antichymotrypsin is probably not actively secreted into amniotic fluid but may be selectively retained after complexing.

Amniotic Fluid↗
PubMed1980

Alpha 1-antichymotrypsin in infected and noninfected sputum.

alpha 1-Antichymotrypsin is a proteolytic enzyme inhibitor believed to be important for protecting tissues from proteolytic damage. Concentrations in the bronchial secretions might therefore be important in relation to the infective process. We studied the protein quantitatively and qualitatively in sputum from patients with bronchitis. In noninfected sputum the concentration of alpha 1-antichymotrypsin relative to protein albumin was 6.48 times higher than that in the serum, suggesting that local mechanisms exist to concentrate or produce this protein. In the presence of acute infections, increased protein transudation from the serum occurred. Although the absolute concentration of alpha 1-antichymotrypsin increased in the sputum, its concentration relative to albumin decreased to 2.09 times that in the serum. Two-dimensional electrophoretic studies of sputum alpha 1-antichymotrypsin showed varying proportions present as "complex," even in the noninfected samples. The electrophoretic mobility of the uncomplexed alpha 1-antichymotrypsin was generally the same as that of serum alpha 1-antichymotrypsin.

Albumins↗
PubMed1980

Assessment of 7S and 11S immunoglobulin A in sputum.

The concentrations of "secretory piece" and total IgA, and the amount of IgA present as the 11S and 7S components, were studied in sputum. The results showed that all were present in greater quantities in infected than non-infected samples. The secretory piece measurements were correlated with measurements of the 11S IgA component in the infected samples, suggesting that all of the secretory piece was attached to the 11S IgA as secretory IgA. However, in the non-infected samples, secretory piece measurements were greater than the 11S IgA measurements, suggesting the presence of free secretory piece. The ratio of sputum to serum concentration of 7S IgA in both groups of samples was several times higher than the respective albumin ratios (average values for infected samples = 3.08 x albumin; average values for non-infected samples = 5.52 x albumin). This suggests that most of the 7S IgA present in sputum is also locally produced within the lung.

Blood Proteins↗
PubMed1980

The electrophoretic mobility of alpha 1-antitrypsin in sputum and its relationship to protease inhibitory capacity, leucocyte elastase concentrations and acute respiratory infection.

The electrophoretic mobility of uncomplexed alpha 1-antitrypsin was studied in the sol phase of sputum from 14 patients with chronic bronchitis. The mobility of alpha 1-antitrypsin in the sputum of each subject was reduced compared to the mobility in serum (mean sputum value = 71.1% of albumin mobility; mean serum value = 78.5% of albumin mobility). This reduction in alpha 1-antitrypsin mobility was most significant in the sputum samples of patients with chest infections which contained free elastolytic activity (mean value in cases where no enzyme activity was found = 74.9%; in cases with enzyme activity = 66.1%, 2P < 0.01). There was a significant inverse relationship between alpha 1-antitrypsin mobility in sputum and concentration of immunoreactive leucocyte elastase (r = -0.739, 2P < 0.01). The addition of trypsin to the sputum samples showed failure to inhibit the enzyme despite the apparant presence of sufficient uncomplexed alpha 1-antitrypsin in these samples, suggesting this alpha 1-antitrypsin was non-functional. Proteolytic enzymes can inactivate alpha 1-antitrypsin with a reduction in its electrophoretic mobility. The results of this study suggest that the alpha 1-antitrypsin in sputum may be inactivated by lysosomal proteases including elastase.

Bronchitis↗
PubMed1980

Granulocyte transfusions: current status.

Since granulocyte transfusions first became widely used in clinical medicine, there have been advances in the treatment of acute leukemia and improvement in prevention and management of infection in neutropenic patients. Improved understanding now exists concerning prognosis of infections in such patients, and advances have been made in procurement of granulocytes. Granulocyte transfusions should be given for specific indications, and used adjunctively to other established antiinfective therapy. Once initiated, transfusions should be given in adequate doses at daily intervals (at least) with ongoing evaluation and periodic reassessment of the whole antiinfective program. Serious complications of granulocyte transfusion therapy are relatively rare, but the physician should be prepared to manage them intelligently. Research continues in discerning exactly how granulocyte transfusion work, in preservation of granulocytes, and in delineation of immunologic phenomena affecting the efficiacy of such therapy. Granulocyte transfusions will continue to be important in the management of acute leukemia, and other reversible bone marrow failure states, and in marrow transplantation and autotransplantation.

Antibody Formation↗