Comparison of low-dose intramuscular and intravenous salcatonin in the treatment of primary hyperparathyroidism.

The treatment of hypercalcaemia with low-dose salcatonin (100 U/d), administered either as a single intramuscular bolus or as a continuous intravenous infusion for five days, was examined in two groups of 10 patients with primary hyperparathyroidism, in a randomized open parallel study. Both the peak (0.31 +/- 0.035 mmol/L v 0.13 +/- 0.034 mmol/L) and overall (0.073 +/- 0.016 mmol/L v 0.018 +/- 0.016 mmol/L) hypocalcaemic responses were greater in the infusion group. The peak reduction in serum calcium occurred on day 2 of treatment after which there was a progressive attenuation of response. All the differences between the two methods of administration wer due to renal rather than bony effects of salcatonin. Possible causes of progressive resistance to treatment included reductions in sodium excretion and serum phosphate. It is concluded that low-dose salcatonin administered as a continuous infusion was more effective than the same dose given as a bolus. The kidney played a pivotal role both in the cause of the hypercalcaemia and in the response to treatment, including the rapid development of resistance which limits the use of salmon calcitonin in primary hyperparathyroidism to short-term reduction of serum calcium.

The renal response to exogenous parathyroid hormone in treated pseudohypoparathyroidism.

Resistance to the renal actions of parathyroid hormone (PTH) in pseudohypoparathyroidism (PsH) may be improved after treatment with vitamin D or its metabolites, but reports conflict. We have examined the renal response to infusion of 35 micrograms of 1-38 PTH in patients with PsH type I (n = 8) and PsH type II (n = 1) during treatment and related this to prevailing endogenous serum PTH and calcium levels. Nine patients with postsurgical or idiopathic hypoparathyroidism (HP) served as controls. The urinary cAMP increase (delta cAMP) was lower (p < 0.001) in the PsH type I (175 +/- 6.4 nmol/l glomerular filtrate) than in the HP group (3251 +/- 515 nmol/l glomerular filtrate). delta cAMP in the PsH type I subjects was dependent on endogenous PTH concentrations (r = -0.76; p = 0.046) and serum calcium (r = 0.74; p = 0.037). Phosphaturic responses (expressed as % decrease in TmPO4/glomerular filtration rate) were lower (p = 0.013) in the PsH type I (28.8 +/- 3.75) compared with those of the HP patients (43 +/- 3.48). The phosphaturic responses in the PsH type I patients were strongly dependent on endogenous PTH (r = 0.94; p < 0.001) and serum calcium levels (r = 0.94; p < 0.001) so that the responses of subjects with normal or low PTH levels were no different (p = 0.16) from the HP group. Renal handling of calcium and sodium in response to exogenous PTH was identical in patients with PsH (types I and II) and HP. Renal tubular reabsorption during a calcium infusion was normal in all patients with PsH. These results emphasise the importance of the modulatory effects due to associated biochemical abnormalities in PsH on the responses to exogenous PTH. They also confirm that renal handling of calcium and sodium is probably normal in treated PsH.

An evaluation of the Olympus "Quickrate" analyser.

The Olympus "Quickrate", a photometer built for both kinetic and end point analysis was evaluated in this laboratory. Aspartate transaminase, lactate dehydrogenase, hydroxybutyrate dehydrogenase, creatine kinase, alkaline phosphatase and gamma glutamyl transpeptidase were measured in the kinetic mode and glucose, urea, total protein, albumin, bilirubin, calcium and iron in the end point mode. Overall, good correlation was observed with routine methodologies and the precision of the methods was acceptable. An electrical evaluation was also performed. In our hands, the instrument proved to be simple to use and gave no trouble. It should prove useful for paediatric and emergency work, and as a back up for other analysers.

Guidelines (1988) for training in clinical laboratory management. International Federation of Clinical Chemistry (IFCC) Education Division and International Union of Pure and Applied Chemistry (IUPAC) Clinical Chemistry Division Commission on Teaching of Clinical Chemistry.

Trainees in laboratory medicine must develop skills in laboratory management. Guidelines are detailed for laboratory staff in training, directors responsible for staff development and professional bodies wishing to generate material appropriate to their needs. The syllabus delineates the knowledge base required and includes laboratory planning and organisation, control of operations, methodology and instrumentation, data management and statistics, financial management, clinical use of tests, communication, personnel management and training, and research and development. Methods for achievement of the skills required are suggested. A bibliography of IFCC publications and other material is provided to assist in training in laboratory management.

A comparison of the measurement of sodium and potassium by flame photometry and ion-selective electrode.

Although sodium and potassium have been the most commonly assayed analytes by clinical chemists for many years there have been fewer analytical principles used routinely than for most other analytes. The introduction of the direct-reading ion-selective electrode has led to a re-examination of the basic concepts of the methods involved, and this in turn to a reassessment of the interpretation of the measurement of sodium in certain clinical situations. As a result there is a case for all clinical chemistry laboratories having access to a direct-reading ion-selective electrode for sodium estimation.

An investigation into the automated measurement of urinary oestrogens ha pregnancy.

Changes in the relative sensitivity of reaction oestrone, oestradiol, oestriol, and their monoglucuronides due to changes in reaction temperature and the acid a nd quinol concentrations of Kober's reagent have been investigated by means of an automated system. Similar investigations have been carried out with a number of standardized pregnancy urines. All measurements have been made with reference to an oestriol-16(beta-D-glucuronide)standard. These changes have been examined with trichloracetic acid and p-nitrophenol in Ittrich's reagent. The importance of the final acid concentration has also been examined. As a result of these investigations a modified scheme is suggested which gives maximal sensitivity to oestriol conjugates and minimal sensitivity to oestradiol conjugates, and may be calibrated by using an oestriol conjugate as a primary standard. The effect of varying the concentration of trichloracetic acid and p-nitrophenol in Ittrich's reagent has been examined under these modified conditions. More than 200 urines have been assayed by this method and the results compared with those obtained by the present automated procedure. The effect of dilution on many of these specimens has also been examined.

Dried blood spot test estimation of urea.

The analysis of urea in serum and whole blood samples dried onto filter paper has been investigated. In both cases the sample volume is not critical nor is the volume of sample applied to the filter paper if sample discs of consistent dimensions can be punched from the dried paper. The method must be calibrated by a serum-based material not an aqueous standard, presumably because of a matrix effect. A coefficient of variation of approximately 6% has been achieved over a wide range of urea concentration and the method has been shown to correlate well with a standard laboratory procedure. The technique has a particular application to neonatal capillary samples.

Determination of bilirubin in amniotic fluid: a comparison of some current methods.

Three methods for the estimation of bilirubin in amniotic fluid are compared. The within-batch precision and recovery of bilirubin by each method has been studied, and the effects of the presence of haemoglobin, methaemoglobin, and methaemalbumin in varying concentrations have been investigated. Measurements on amniotic fluid from patients with rhesus isioimmunization have also been compared and regression equations calculated. The results of the three methods agree reasonably well so long as no haemoglobin degradation products are present. It is suggested that in the presence of these products a method involving organic solvent extraction of bilirubin gives the most accurate result.

Some ionic and dilution effects in the measurement of urinary oestrogens in pregnancy.

The estimation of oestrogen in aqueous solutions and pregnancy urines using an automated procedure is affected by the presence of certain ions, and by dilution. These effects have been studied by calculating regression equations from the values obtained with urines to which ions have been added with and without urine dilution. The results suggest that the ionic effect is chemical rather than physical and that there is no advantage in including a predilution step in the analysis. Other means of removing the ionic effects have so far proved unsuccessful.

Pseudohypophosphataemia as a result of bilirubin interference.

During the routine use of a discrete analyser it was noted that, when the serum bilirubin concentration was greater than 50 mumol/L, there was interference with serum phosphate determination measured by the formation of unreduced phosphomolybdate using a bichromatic system of measurement. The degree of interference was assessed by comparison with a reduced phosphomolybdate method (molybdenum blue). The interference cannot be removed by changing the secondary wavelength or by the use of a sample blank. It is proportional to the serum bilirubin concentration, but is not significant when this is less than 50 mumol/L. The monochromatic non-reduced phosphomolybdate method compares well with the reduced method.

International Federation of Clinical Chemistry Education Division and International Union of Pure and Applied Chemistry Clinical Chemistry Division Commission on Teaching of Clinical Chemistry. Guidelines (1988) for training in clinical laboratory management.

Trainees in laboratory medicine must develop skills in laboratory management. Guidelines are detailed for laboratory staff in training, directors responsible for staff development and professional bodies wishing to generate material appropriate to their needs. The syllabus delineates the knowledge base required and includes laboratory planning and organisation, control of operations, methodology and instrumentation, data management and statistics, financial management, clinical use of tests, communication, personnel management and training, and research and development. Methods for achievement of the skills required are suggested. A bibliography of IFCC publications and other material is provided to assist in training in laboratory management.

Assessment of fetal lung maturity by colorimetric phospholipid determination without digestion.

A previously described method for the determination of phospholipid concentration in amniotic fluid without digestion has been modified to make it more suitable for use in a routine laboratory. Results compare well with those by the original procedure. Results from nearly 70 amniotic fluids, collected at delivery, were compared with lecithin/sphingomyelin (L/S) ratios determined on the same fluids. Statistical analysis of these data showed that for the prediction of lung immaturity, determination of total phospholipid concentration was at least as good as the L/S ratio.

Critical assessment of phospholipid measurement in amniotic fluid.

We assessed several methods of inorganic phosphate assay for their suitability in estimating phospholipids in digested extracts of amniotic fluids. The extraction and digestion procedures used for phospholipids from amniotic fluid were also examined critically. The effect of contamination by blood or obstetric cream has been examined. Accordingly, we suggest a method for measuring total phospholipids in amniotic fluids, and results of it are compared with the lecithin/sphingomyelin ratio measurement in some clinical situations.

Carboxyhemoglobin determination by second-derivative spectroscopy.

In this procedure hemoglobin is converted to its reduced form and the magnitude of the zero-order spectral shift of the reduced hemoglobin peak at 430 nm to the carboxyhemoglobin peak at 418 nm is determined by second-derivative spectrum analysis. The method is simple, straightforward to set up, and rapid. A result may be obtained within 15 min of receiving the sample. It is sufficiently sensitive to differentiate carboxyhemoglobin concentration in the blood of smokers and nonsmokers.