Search PubMed⌕ Search

Biomedical subjects

J W Halliday

Publications and source records attributed to J W Halliday.

At least 127 records · Page 7Linked to original sources
PubMed1980

Effect of long-term corticosteroid therapy on monocyte chemotaxis in man.

The influence of prednisolone on monocyte chemotactic activity in vitro at prednisolone concentrations comparable with those achieved in man following oral dosage has been investigated. Chemotactic activity of monocytes from each of sixteen normal subjects was suppressed by concentrations of prednisolone as low as 25 ng/ml (suppression of chemotaxis, 20%). Maximal suppression occurred at 100 ng/ml (suppression of chemotaxis, 48%) and no significant increase in suppression was produced by increasing the concentration to 200 ng/ml (suppression of chemotaxis, 53%). In contrast, monocytes isolated from ten patients receiving corticosteroid therapy showed no significant suppression of chemotactic activity when exposed to these concentrations of prednisolone, even though they exhibited a normal ability to respond to a chemotactic stimulus. The lack of suppression of monocyte chemotaxis in patients receiving corticosteroid therapy is unexplained, but may represent a change in the circulating monocyte or lymphocyte populations.

Administration, Oral↗
PubMed1980

A report on two interlaboratory surveys of serum ferritin estimation.

Two surveys of the proficiency of performance of serum ferritin estimation in Australia have been conducted, one in 1978 and one in 1979. The majority of participants in both surveys used assay kits supplied by Clinical Assays, Roche Diagnostics and Ramco. The first survey showed a median intrabatch variation 9% and median interbatch variation of 17%. The overall assay variation had a median level of 22%. Assays by the various kits gave values which were not significantly different for each specimen (including purified liver and spleen ferritin solutions). The second survey showed an improvement in the overall precision of the participants with a median coefficient of variation of 15%. Contrary to the first survey, significant differences were evident between the results in 4 of the 5 specimens assayed. Some participants returned results for the high ferritin serum that differed substantially depending on the dilution of the sample used. The surveys showed a need for improvement in the assay performance of some participants, the need for ferritin levels to be assayed at least in two dilutions, and the need for standardization of assays, reference ranges and reporting units. Recommendation are made on all these points.

Ferritins↗
PubMed1980

Report of the survey of hepatitis antigens in the Asian-Pacific region.

The aim of the study was to determine the prevalence of Hepatitis antigens e.g. Hepatitis B surface antigen (HBsAg), anti-HBsAg Hepatitis A and non A and B in liver diseases and in blood donors, hospital staff, specific population and general population in various countries in the Asian Pacific Region through published data and questionnaires. The study confirmed previous data indicating a high prevalence of Hepatitis B in certain areas of the Asian Pacific region. The problem of chronic hepatitis, non A, non B hepatitis will become clearer with more sensitive assays.

Blood Donors↗
PubMed1980

Prednisolone pharmacokinetics in asthmatic patients.

Prednisolone serum levels have been measured by radio-immunoassay in 12 steroid-dependent asthmatic patients. Differences in prednisolone pharmacokinetics did not account for the variation in dose of prednisolone required to control asthma.

Adult↗
PubMed1979

The nature of piecemeal necrosis in chronic active hepatitis.

On the basis of histological studies, it is proposed that the type of liver-cell death in piecemeal necrosis is apoptosis. The characteristic inconspicuousness of apoptosis explains why the mode of hepatocyte elimination in piecemeal necrosis has hitherto remained obscure. Cell-mediated immune attack induces apoptosis, not classical necrosis, and the occurrence of apoptosis in piecemeal necrosis links the observed morphological changes in chronic active hepatitis with the other evidence for an autoimmune pathogenesis. It is significant that apoptosis does not evoke inflammation or fibroplasia. In attempting to elucidate the cause of the fibrosis that accompanies progression to cirrhosis in chronic hepatitis, it may thus be more relevant to study the effect on fibroblasts of substances liberated during lymphocyte-hepatocyte interactions than the death of the hepatocytes.

Autoimmune Diseases↗
PubMed1979

Early detection of idiopathic haemochromatosis: relative value of serum-ferritin and HLA typing.

A study of 18 unrelated families with idiopathic haemochromatosis (I.H.C.) was undertaken to define the relative values of HLA typing and serum-ferritin estimation in the early detection of the disease. Sharing of both HLA haplotypes with the proband indicated a high risk of I.H.C. in siblings; but HLA typing was of limited value in detecting affected offspring. Non-identical HLA indicated a low risk of I.H.C. in both siblings and offspring. The presence of HLA A3 was not clinically useful as a marker for I.H.C., since this antigen was also present in 40% of unaffected relatives. In contrast, the serum-ferritin concentration was elevated in 96% of patients with I.H.C. and in only 5% of unaffected relatives. HLA typing provides some indication of the risk of I.H.C. in first-degree relatives, but the combination of serum-ferritin, serum-iron, and transferrin saturation remains the most reliable screening regimen for early diagnosis of I.H.C.

Adolescent↗
PubMed1979

Concurrent administration of antacids and prednisone: effect on serum levels of prednisolone.

1 Specific radioimmunoassays have been developed for the measurement of prednisolone and prednisone in serum. 2 Serum prednisolone levels have been measured following the administration of prednisone both with and without antacids. 3 There were no significant differences in the values of Cmax (mean +/- s.d.) (251 +/- 80 ng/ml with, 245 +/- 69 ng/ml without antacid), AUC (1430 +/- 469 ng ml-1 h-1 with, 1406 +/- 530 ng ml-1 h-1 without antacid) or Tmax (1.6 +/- 0.6 h with, 1.6 +/- 0.8 h without antacid). 4 Serum prednisone levels were less than 20% of prednisolone levels at all time intervals in the subjects studied. 5 Concurrent antacid administration has no significant effect on serum prednisolone levels attained.

Antacids↗
PubMed1979

The kinetics of serum and tissue ferritins: relation to carbohydrate content.

Significant differences were observed in the rate of disappearance from plasma of ferritins purified from rat serum and from different organs. Ferritin from all sources including purified serum ferritin was rapidly removed from plasma by the liver. No difference in biological half-life was observed between apoferritin prepared by ultracentrifugation of liver ferritin and whole liver ferritin and iron-loaded animals cleared injected serum ferritin from plasma at a comparable rate to normal rats. When amounts of 100 microgram of ferritin were injected into rats the half-life was significantly lengthened. The study confirmed the fact that ferritin iron and ferritin protein were removed from plasma at the same rate. No consistent effect of acidic or more basic isoferritin composition on biological half-life was apparent. After chromatography on concanavalin A-Sepharose 6B those ferritins which were predominantly bound to Con A-Sepharose had a half-life which was approximately twice that of ferritins which did not bind. It is concluded that the variation in plasma disappearance of ferritins of different tissue origin was explainable on the basis of carbohydrate content of the molecule.

Animals↗
PubMed1978

Relationship between serum ferritin and total body iron stores in idiopathic haemochromatosis.

The relationship between the serum ferritin concentration and total body iron stores was investigated in 41 patients with idiopathic haemochromatosis and 199 first or second degree relatives. Thirty-two relatives (16.1%) had increased iron stores and serum ferritin levels were increased in all but one of them. The false-positive rate in the relatives with normal iron stores was 1.8% compared with 10% for the serum iron concentration and 33% for the transferrin saturation. There was a significant correlation between the serum ferritin concentration and both the chelatable body iron and the hepatic iron concentration. We conclude that in the natural history of classical idiopathic haemochromatosis the serum ferritin concentration is usually raised when hepatic iron stores are increased and before there is architectural damage to the liver.

Adolescent↗