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Biomedical subjects

P J Howorth

Publications and source records attributed to P J Howorth.

At least 37 records · Page 2Linked to original sources
PubMed1975

Evaluation of a kit (Thyrolute) for the combined determination of serum total thyroxine and sequential free thyroxine index using Sephadex G-25 and 125I-thyroxine.

A new kit (Thyrolute, Ames) for the combined determination of serum total thyroxine (T-4) and sequential free thyroxine index (F.T.I.) using Sephadex G-25 and 125-thyroxine was evaluated in 136 patients and normal subjects. The T-4 determination was virtually identical to that used in the Ames Tetralute kit and had a similar accuracy and precision. The sequential F.T.I. was compared with a two-stage F.T.I. The two F.T.I.s showed highly significant correlations in the various groups of patients except euthyroid women with raised thyroxine-binding globulin (TBG) (pregnant or oral contraceptive). The overlap found for the sequential F.T.I. between euthyroid, hypothyroid, and thyrotoxic patients was slightly inferior (9%) to that found with the two-stage F.T.I. (6%), but its diagnostic success rate was higher than that of the serum T-4 determination alone. Serial observations of serum T-4 and sequential F.T.I. were also made on eight patients receiving carbimazole-therapy for hyperthyroidism. The sequential F.T.I. showed complete parallelism with serum T-4 regardless of thyroid status, so that it was of no practical value in these patients. It was concluded that the sequential F.T.I kit would be of most value in the smaller hospital laboratory lacking facilities for the radioimmunoassay of thyroid hormones and thyroid stimulating hormone.

Adolescent↗
PubMed1975

The physiological assessment of acid-base balance.

Acid-base terminology including the sue of SI units is reviewed. The historical reasons why nomograms have been particularly used in acid-base work are discussed. The theoretical basis of the Henderson-Hasselbalch equation is considered. It is emphasized that the solubility of CO2 in plasma and the apparent first dissociation constant of carbonic acid are not chemical constants when applied to media of uncertain and varying composition such as blood plasma. The use of the Henderson-Hasselbalch equation in making hypothermia corrections for PCO2 is discussed. The Astrup system for the in vitro determination of blood gases and derived parameters is described and the theoretical weakness of the base excess concept stressed. A more clinically-oriented approach to the assessment of acid-base problems is presented. Measurement of blood [H+] and PCO2 are considered to be primary data which should be recorded on a chart with in vivo CO2-titration lines (see below). Clinical information and results of other laboratory investigations such as plasma bicarbonate, PO2,P50 are then to be considered together with the primary data. In order to interpret this combined information it is essential to take into account the known ventilatory response to metabolic acidosis and alkalosis, and the renal response to respiratory acidosis and alkalosis. The use is recommended of a chart showing the whole-body CO2-titration points obtained when patients with different initial levels of non-respiratory [H+] are ventilated. A number of examples are given of the use of this [H+] and PCO2 in vivo chart in the interpretation of acid-base data. The aetiology, prognosis and treatment of metabolic alkalosis is briefly reviewed. Treatment with intravenous acid is recommended for established cases. Attention is drawn to the possibility of iatrogenic production of metabolic alkalosis. Caution is expressed over the use of intravenous alkali in all but the severest cases of metabolic acidosis. The role of 2,3-diphosphoglycerate on tissue oxygenation is stressed and use of intravenous sodium phosphate as an alternative to intravenous bicarbonate is mentioned.

Acid-Base Equilibrium↗
PubMed1974

RIpH revisited.

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Acid-Base Equilibrium↗
PubMed1974

Implementation of a British computer system for laboratory data handling.

This paper describes the development and implementation of a small real-time British computer system for the handling of patient and test result data in the chemical pathology laboratories of the King's Health District (Teaching). Work destined for subsequent reporting by the computer system is entered by continuous on-line teletype. Test result data from multichannel analyzers are input using an on-line trace reader. Cumulative reports are printed both by line printer at the central laboratory and by on-line teletypes at two peripheral hospital laboratories. In a working day over 4000 new items of data are generated and 300-500 reports printed. The use of a trace reader as an inputing device and the method of employing a high capacity disk to give both speed of operation and limited archive facility are discussed.

Computers↗
PubMed1974

Evaluation of new kits for the assessment in vitro of thyroid function by determination of serum total thyroxine, free TBG capacity, and free thyroxine index Sephadex G-25 and 125I-labelled triiodothyronine and thyroxine.

A trial was carried out on 134 patients of new kits (Ames Co) using columns of Sephadex G-25 for the determination of serum total thyroxine (Tetralute test) and for the indirect estimation of serum free thyroxine-binding globulin capacity (Trilute test). Both new methods were quicker and easier than the reference resin methods and of similar precision. The two measurements when combined to give a free thyroxine index (Trilute-Tetralute-FTI) increased further the diagnostic discrimination and usefulness of the tests. The method for the determination of serum thyroxine can be modified to give a direct estimate of serum free thyroxine, expressed as a free thyroxine index. This new single-column technique, called the ;single-column free thyroxine index', gave a good correlation with clinical thyroid status in a preliminary trial of 45 patients.

Adolescent↗
PubMed1972

The T 4 -free thyroxine index as a test of thyroid function of first choice.

The T(4)-free thyroxine index was used as the thyroid function test of first choice in a district general hospital for one year. Ninety-two patients were assessed both initially and at follow up by a single physician. The index agreed with clinical assessment in 69 out of 74 patients in whom diagnosis was unequivocal. There was initial doubt about thyroid status in 14 patients; after re-assessment the index agreed with status in seven cases, in three cases there is still some uncertainty, whilst the index was at variance with clinical status in four patients. Some possible causes of discrepancy between clinical thyroid status and the index are a low index in euthyroid patients due to a fall in serum thyroxine-binding prealbumin (;sick euthyroid'), a raised index in euthyroid patients due to latent thyroid heart disease, and a normal index in thyrotoxicosis due to preferential secretion of triiodothyronine.

Adult↗
PubMed1968

Determination of uric acid levels in uraemia by enzymatic and colorimetric techniques.

Serum uric acid levels were determined by specific and non-specific methods in uraemia in order to investigate the correlation between non-specific chromogen and serum urea level. The correlation was moderate and the magnitude of the non-specific chromogen was smaller than had been reported previously. The ratio [Formula: see text] urate was found to be 0.85 in both acute and chronic renal failure, a ratio very similar to that previously reported for normal and gouty subjects. In chronic renal failure the true uric acid level is correlated with urea level and there is a suggestion that serum uric acid levels in chronic renal failure are lower for a given urea value than in acute renal failure.

Acute Kidney Injury↗