Immunofixation and immunosubtraction on agarose gel: an aid in the typing of monoclonal gammopathies.

A simple immunosubtraction technique and its application to a standard immunofixation procedure is described. Examples are presented where monoclonal immunoglobulin bands were successfully classified using immunosubtraction after other techniques had failed.

Severe repetitive exercise and haematological status.

The effects of severe repetitive exercise on certain haematological measurements were studied. Decreases in haematocrit and haemoglobin (13% in one group of participants) took place during the first 2 weeks but not the third week of increasingly severe exertion and the reasons for this are discussed. Haemolysis probably plays only a small part and plasma volume expansion is likely to be the main cause of this phenomenon. It is suggested that there is no stimulus for the haemoglobin concentration to be increased to match the increased plasma volume as tissue oxygen tension is maintained satisfactorily.

A study on the effects of severe repetitive exercise on serum myoglobin, creatine kinase, transaminases and lactate dehydrogenase.

Two groups of young men taking part in a 24-day training course involving increasingly severe exercise were studied. Serum myoglobin, creatine kinase, creatine kinase-MB, transaminases, lactate dehydrogenase, urea, creatinine, calcium and uric acid were estimated at intervals. During the first few days, increases in myoglobin and muscle enzymes correlated with the severity of the preceding exercise. Increases in myoglobin and muscle enzymes after the final most severe exercising were less than with the initial exercising, demonstrating the effect of physical training. The changes in myoglobin and the muscle enzymes correlated closely. Elevated myoglobin levels persisted for over 24 hours. There was no consistent correlation between changes in myoglobin and uric acid, both of which have been considered responsible for the renal failure which may occur with rhabdomyolysis.

A regional external quality assessment scheme for serum thyroxine-binding globulin.

The results from a Regional External Quality Assessment Scheme for the assay of serum thyroxine binding globulin (TBG) are presented. It has been shown that different methods of analysis (eg, rocket immuno-electrophoresis, radioimmunoassay, and radial immunodiffusion) produce comparable results using a common calibrant. Since there is no commonly agreed universal calibrant for TBG, however, results (in mg/l) for various assay systems with differing methods of calibration show wide variance.

The T4:TBG ratio: a re-evaluation with particular reference to low and high serum TBG levels.

The thyroxine: thyroxine-binding globulin (T4: TBG) ratio is now an established part of the biochemical investigation of thyroid function. Reference ranges have been reported for euthyroid subjects with TBG levels within the range 6-16 mg/l. Routine assay of TBG on all thyroid function tests in this laboratory has suggested that, in patients with low or high TBG levels, the established reference ranges for T4: TBG may not be strictly applicable. A retrospective study has been made of a large number of thyroid function requests, including serum total T4, free T4, TBG, and TSH assays. Evidence is presented to show that in subjects with a TBG level of less than 8 mg/l the reference range for T4: TBG is elevated. Similarly, in subjects with a TBG greater than 16 mg/l, the reference range for T4: TBG is lowered. The data suggest that it is necessary to quote a T4: TBG reference range based on small increments of TBG levels or to relate total T4 reference ranges to those increments.

An improved continuous flow method for serum creatinine using the Jaffé reaction.

A method for the measurement of creatinine is described in which serum is dialysed directly into a combined alkaline picrate reagent. Baseline noise and drift are eliminated, and precision is improved by avoiding the need to add further reagents after dialysis. This may be of particular interest to laboratories that perform this assay on first-generation AutoAnalyzer equipment.

The T3/TBG ratio and the biochemical investigation of thyrotoxicosis.

The relationship between serum tri-iodothyronine (T3) and thyroxine-binding globulin (TBG) has been studied in euthyroid subjects. This relationship is similar to that previously described for thyroxine (T4) and TBG. Serum T3, TBG and T4 data are presented for euthyroid subjects of all ages and the T4:T3 and T3:TBG ratios calculated. Similar data has been derived for patients with clinically proven thyrotoxicosis and for patients in which the diagnosis was in doubt. The results suggest the T3:TBG ratio enhances the use of the T3 assay to confirm thyrotoxicosis. The fact that 25% of our patients suffering from thyrotoxicosis had apparently normal serum T4 levels reinforces the contention that a serum TBG assay must be carried out as part of a basic thyroid function screen.

An assessment under routine conditions of an immunoelectrophoretic assay for thyroxine-binding globulin.

The correct clinical interpretation of serum total thyroxine requires a knowledge of the thyroxine binding globulin (TBG) concentration. An immunoelectrophoretic method for TBG assay has been assessed under routine conditions for precision, sensitivity and recovery. TBG has been compared with T3 Resin Uptake for euthyroid subjects, and patients with myxoedema and thyrotoxicosis. The relationship between TBG and age has also been studied. The method proved to be reliable, sensitive and a technically simple method for the routine determination of TBG and an excellent replacement for the indirect T3 Resin Uptake Test.

Total urine oestriol by a modification of a commercial plasma oestriol kit.

An adaptation of a radioimmunoassay for plasma oestriol for assaying urine oestriol is presented. The method has been shown to be precise, reliable, and directly comparable with the manual spectrophotometric technique for urine oestriol.

The T4/TBG ratio and the investigation of thyroid function.

The relationship between serum thyroxine (T4) and thyroxine-binding globulin (TBG) has been studied in "euthyroid" subjects. The T4/TBG ratios in these subjects has been calculated and compared with those found in patients suffering from myxoedema and thyrotoxicosis. The ratio allows a more precise selection of the borderline cases requiring Thyroid Stimulating Hormone and triiodothyronine assays, particularly when the serum TBG is raised or lowered.

A survey of the haematological, nutritional and biochemical state of the rural elderly with particular reference to vitamin C.

A survey of the rural elderly has been carried out to determine basic haematological and biochemical data, and to establish a pattern of living for this 'well' population. The blood parameters related to diet, such as haemoglobin, folate, cholesterol, vitamin C etc., show considerable changes with increasing age in the male but little significant change in the female. The vitamin C status for both sexes compares favourably with that reported by other workers studying the urban elderly. The biochemical and haematological data derived provide a normal range with which the 'sick' elderly can be compared. The subjects were generally active and independent in spite of (or because of) a somewhat Spartan existence.

Vitamin C and post-suxamethonium pains.

A double-blind trial of the effects of vitamin C on the frequency, severity and duration of post-suxamethonium pains was performed. Fifty-three patients undergone bronchoscopy received either a placebo or 10 g of vitamin C. No beneficial effect was demonstrated. In 18 patients no relationship was found between pre-anaesthetic buffy layer vitamin C levels and the subsequent pains. Measurement of buffy layer and plasma vitamin C levels before and after anaesthesia did not suggest that vitamin C deficiency occurs during or immediately after administration of suxamethonium. It is concluded that the administration of vitamin C cannot be recommended as a means for prevention of suxamethonium pains.

The accuracy of commercial calibration sera and assayed control sera.

Commercial calibration sera and assayed control sera have been extensively studied in parallel runs. An attempt has been made to assess the accuracy of the stated values of these sera, using mehtods that in two major quality control schemes have been shown to be reliably accurate. The Technicon product has proven to be generally the most reliable of the calibration sera. Many discrepancies were found in the assayed control sera values, particularly for calcium, phosphate and bilirubin, and our results indicate that the products of some manufacturers need to be improved.