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Biomedical subjects

J D Teale

Publications and source records attributed to J D Teale.

At least 55 records · Page 3Linked to original sources
PubMed1989

Insulin-like growth factor-I in the parenterally fed low birth weight infant.

Postnatal change in insulin-like growth factor-1 (IGF-I) was studied longitudinally in 9 very low birth weight infants (less than 1,200 g, less than 30 weeks at birth) who were receiving 85% or more of their nutrient intake via the parenteral route. There was no apparent relationship between IGF-I, nitrogen intake, energy intake, or nitrogen retention. In 6/9 infants IGF-I decreased with postnatal age. A low IGF-I may reflect the poor nutritional status and growth rate commonly seen in sick preterm infants.

Energy Intake↗
PubMed1989

The measurement and effect of growth hormone in the presence of growth hormone-binding antibodies.

We have developed methods for measuring the concentrations of free GH in plasma using a polyethylene glycol (PEG) separation procedure to remove antibody-bound GH within 1 h of collection. Total GH concentrations were obtained by acidification of the GH-antibody complex to release the GH followed by PEG precipitation of the antibody. The plasma GH assay had a within-assay coefficient of variation (C.V.) of 6.8% at 4.6 mU/l and a between-assay C.V. of 9.2% at 4.0 mU/l. The PEG-modified assay had a within-assay C.V. of 4.3% at 6.3 mU/l and a between-assay C.V. of 10.9% at 5.3 mU/l. Both assays had a sensitivity of 1.3 mU/l. There was good correlation between plasma and free GH concentrations in 24-h profiles in two tall children (r = 0.98; P less than 0.001) and between total and free GH in the same profiles (r = 0.97; P less than 0.001). GH antibodies were measured using a highly sensitive radioimmunoassay. In children who did not develop GH antibodies there was no difference between total, plasma and free GH concentrations. In contrast, in those who developed GH antibodies both total and plasma GH concentrations were markedly increased compared with free GH concentrations. The presence of GH antibodies did not affect the growth, plasma insulin-like growth factor-I concentrations or fasting serum insulin concentration responses to 1 year of therapy with biosynthetic human GH.

Autoantibodies↗
PubMed1988

Postoperative positive nitrogen balance with intravenous hyponutrition and growth hormone.

11 patients having major gastrointestinal surgery were allocated at random to receive either biosynthetic human growth hormone (BSHGH) 0.1 mg/kg or placebo daily for the first 7 postoperative days. All patients received the same intravenous feeding regimen, which contained 2.09 MJ glucose, 1.88 MJ fat, and 7 g N daily. Patients receiving BSHGH were in positive nitrogen balance throughout the study (mean 1.8 [SEM 0.4] g N/day) and those receiving placebo were in negative nitrogen balance (mean -0.9 [0.7] g N/day). Resting energy expenditure progressively increased in the patients receiving BSHGH (115.7% [14.8] on day 7) but remained unchanged in patients receiving placebo (99.35% [1.4]). Fat oxidation was nearly three times higher in the patients on BSHGH (4.09 [0.38] MJ/day) than in controls (1.38 [0.50]). Carbohydrate oxidation remained about the same in both groups. Whole-body protein turnover, synthesis, and breakdown were increased in the patients receiving growth hormone.

Aged↗
PubMed1987

Thyroid dysfunction in institutionalised Down's syndrome adults.

This study of 111 institutionalised Down's syndrome subjects and 74 controls found a relatively low risk of hypothyroidism in both groups compared with certain other studies of Down's subjects, which found very high rates of thyroid hypofunction. However, the Down's syndrome group had a significantly raised risk of hypothyroidism (9%), hyperthyroidism (1.8%) and the presence of thyroid microsomal antibodies (29%) compared with the controls and with laboratory reference data. It is recommended that thyroid function testing should be routine in older Down's syndrome subjects, with special attention being given to the clinical status of those with microsomal antibodies present.

Adult↗
PubMed1987

Glycosylated haemoglobin and glucose intolerance in cystic fibrosis.

Sixty four patients, age range 1-20 years, with cystic fibrosis had their tolerance to glucose assessed according to their glycosylated haemoglobin (HbA1) concentrations. Raised concentrations were found in 24 (37.5%). Oral glucose tolerance tests were performed on 21 patients with raised HbA1 and 13 patients with normal HbA1 concentrations. C peptide responses were also measured to assess islet cell function. Patients with normal HbA1 had normal glucose tolerance and C peptide response. Seven of 21 patients with raised HbA1 concentrations were glucose intolerant. The remaining 14 patients with raised HbA1 concentrations had normal glucose tolerance but a reduced C peptide response, suggesting impaired islet cell function. There were no appreciable differences in the incidence of chest infections, respiratory function, and chest x-ray scores among patients with normal HbA1 concentrations, raised HbA1 concentrations, and normal oral glucose tolerant tests, and patients who were glucose intolerant. No correlation was found between HbA1 concentration and age or Shwachman score. Measuring HbA1 concentrations periodically is useful in detecting and monitoring glucose intolerance in patients with cystic fibrosis.

Adolescent↗
PubMed1986

The measurement of insulin-like growth factor I: clinical applications and significance.

Of the somatomedins so far measured, the selective quantitation of insulin-like growth factor I (IGF-I) appears to have the greatest potential in clinical diagnosis. There have been two approaches to the development of immunoassay systems. One type uses antibodies raised against synthetic fragments of IGF-I which exhibit cross-reactivity with the whole hormone. Such assay systems may be adequate for measuring normal adult plasma IGF-I levels, but the potential for the higher sensitivity required for detecting sub-normal plasma levels in young children is apparent only in methods using antibodies raised against the complete hormone. IGF-I in plasma exists as part of a high molecular weight complex in which it is bound to carrier proteins. The binding proteins may interfere with plasma IGF-I measurements by radioligand assays. Direct analysis of untreated plasma samples is claimed to be possible using disequilibrium assay conditions but in order to maximise assay sensitivity it is necessary to employ an initial extraction stage in order to eliminate binding protein interference. Whether the measurement of plasma IGF-I can or should be used in addition to, or as a replacement for, plasma growth hormone (GH) measurement in the clinical assessment of growth disorders remains a controversial issue. Available evidence indicates that a single, random plasma IGF-I level provides an accurate reflection of GH secretion. Adequate discrimination between the elevated levels in acromegaly and normal reference values has been demonstrated. However, in the investigation of growth-retarded children available radioimmunoassay (RIA) methods have proved only partially successful because of the age-related nature of normal plasma IGF-I concentrations. Existing assays appear capable of identifying sub-normal plasma levels after the age of approximately 4 years. In younger subjects an improvement in assay sensitivity is required in order to establish with greater accuracy the relevant normal ranges. Improvements in the identification of the particular lesion responsible for retarded growth in a child can be achieved by measurement of both plasma GH and IGF-I concentrations. The predictive value of the acute plasma IGF-I response to single-dose GH therapy may identify patients who will respond to long-term GH therapy. Better, more informed decisions on subsequent treatment may therefore be made. Apart from GH control, several other factors influence circulating IGF-I levels. Nutritional status can be assessed through reference to IGF-I analysis, overall catabolic or anabolic processes being associated with decreasing or increasing plasma IGF-I levels respectively.

Acromegaly↗
PubMed1977

Radioimmunoassay of bleomycin in plasma and urine.

Antibodies to bleomycin were raised by immunization of sheep and rabbits with bleomycin-albumin conjugates. The combination of a high-titre, high-avidity sheep antiserum and iodinated bleomycin produced a radioimmunoassay sensitive to 8 ng of bleomycin per ml of plasma or urine. Untreated specimens (100 microliter) of plasma or urine could be added directly to the assay tubes. The antiseerum was specific for bleomycin and showed no cross-reaction with other anticancer agents used in combination chemotherapy. Over a concentration range of 20-100 ng/ml, recovery of bleomycin from plasma was 110% and from urine, 93%. Repeated assay of plasma samples showed a decrease in bleomycin levels unless the samples were kept at 4 degrees C or below. Assay of bleomycin levels in plasma and urine from patients under treatment with bleomycin showed similarities with results reported using a microbiological assay. The radioimmunoassay offers a more reliable, rapid and sensitive method for the measurement of bleomycin.

Animals↗
PubMed1977

Radioimmunoassay of vinblastine and vincristine.

1 The cytotoxic agent, vinblastine, was conjugated to albumin, using the Mannich reaction. Rabbits immunized with two conjugates, containing differing amounts of hapten, produce antibodies which bound [3H]-vinblastine. 2 Antisera from one rabbit cross-reacted with both vinblastine and vincristine and were used to develop radioimmunoassays for measuring their concentration in plasma. 3 The antisera showed no cross-reactivity with other alkaloids or cytotoxic drugs and provided assays sensitive to a concentration of 2.1 ng vinblastine or 3.8 ng vincristine/ml of plasma added direct to the assay tubes. 4 This is sufficiently sensitive to permit the measurement of plasma vinblastine levels for up to 24 h after the intravenous administration of 15 mg of the drug.

Animals↗
PubMed1975

The development of a radioimmunoassay for cannabinoids in blood and urine.

Antibodies, for use in radioimmunoassay, have been raised in sheep by immunization with a conjugate of delta9-tetrahydrocannabinol hemisuccinate and bovine serum albumin. Antiserum titre and avidity were increased by successive booster doses of conjugate. The high degree of non-specific binding encountered in the radioimmunoassay of cannabinoids was reduced by the use of the solubilizing detergent Triton X-405 and by restricting protein concentration in the assay medium. Plasma samples were deproteinized with ethanol before assay, but urine was directly assayed. High avidity antibodies and high specific activity [3H]-delta9-tetrahydrocannabinol permitted the detection of 50 pg of cross-reacting cannabinoids--a sensitivity of 7-5 ng ml-1 of plasma and 1-0 ng ml-1 of urine. Whilst apparently specific for the three-ringed cannabinoid nucleus, the assay antiserum cross-reacted with several cannabinoids, both natural compounds and metabolites. Partial identification of cross-reacting cannabinoids was achieved by the use of pure compounds and by the assay of plasma and urine samples collected from rabbits given pure cannabinoids intravenously.

Animals↗
PubMed1975

Plasma cannabinoids measured by radioimmunoassay in rabbits after intravenous injection of tetrahydrocannibinol, 11-hydroxy-tetrahydrocannabinol, cannabinol and cannabidiol.

An antiserum raised in sheep against a conjugate of tetrahydrocannabinol with bovine serum albumin has been used as the basis of a radioimmunoassay for cannabinoids in the blood of rabbits given tetrahydrocannabinol, 11-hydroxy-tetrahydrocannabinol, cannabinol or cannabidiol by rapid intravenous injection. In the case of both 11-hydroxy-tetrahydrocannabinol and cannabinol plasma cannabinoid concentrations fell exponentially from an initial peak plasma level attained immediately after the completion of intravascular distribution of the injected bolus. In the case of tetrahydrocannabinol itself, however, there was a progressive rise in plasma cannabinoid concentration between five and fifteen minutes after the rapid intravenous injection. The reasons for this rise in plasma cannabinoid concentration are discussed.

Animals↗