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BACKGROUND: Revised UK neonatal screening guidelines recommend that a second blood sample for assay of thyroid stimulating hormone (TSH) be taken when preterm infants reach a postmenstrual age of 36 weeks. OBJECTIVE: To examine the results of a regional screening programme to see whether a rise in TSH concentration was observed in some preterm infants between the first sample taken around 5 days after delivery and the second sample taken at around 36 weeks. METHODS: Whole-blood TSH concentrations in preterm infants born over a 2-year period (April 2005 to March 2007) were assessed, and the number of infants in whom there was a fall or rise to values below or above the local screening threshold (6 mU/l) was determined. RESULTS: Baseline TSH samples were obtained from 2238 preterm infants (median gestational age 32 weeks, range 21-35) with second samples obtained from 2039 (median gestational 32 weeks, range 23-35). In 19 infants, TSH concentrations fell from above to below the screening threshold, and in five infants values rose from below the screening threshold to 6-10 mU/l. However, TSH concentrations fell to <6 mU/l on a further blood spot in four of these infants, and the remaining infant had a serum TSH of 6.8 mU/l. Three infants had raised TSH concentrations on both occasions with unequivocal hypothyroidism (serum TSH >80 mU/l). The initial TSH concentration in one of these infants was 6-10 mU/l. CONCLUSIONS: No infant with a normal TSH concentration on first sampling had a TSH concentration that rose above 10 mU/l on second sampling, and no infants with a normal TSH concentration on first screening are receiving long-term thyroxine treatment. This study suggests that a second sample may not be necessary with a screening threshold of 6 mU/l.

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BACKGROUND: The objective of this study was to determine the minimum volume of blood that should be discarded from a range of different types of central venous catheter (CVC), such that the subsequent blood sample was not diluted or contaminated by the residual intra-luminal fluid. PROCEDURE: Seventy children aged 1-19 years with central venous access inserted as part of their standard clinical treatment were recruited to this prospective study. Statistical comparison of the extent of variation in biochemical and haematological parameters observed between two blood samples taken following routine 5 ml discard blood volumes, as compared to the extent of variation between samples drawn following a 5 ml discard volume and <5 ml volumes, was carried out. RESULTS: Data indicate that the measurement error in a clinical sample obtained following a 3 ml discard volume is no different to the measurement error obtained when using a standard 5 ml discard volume. Comparable results were obtained from patients with various different types of CVC or portacath access. CONCLUSIONS: The withdrawal of a 3 ml discard volume is sufficient to ensure that the subsequent blood sample is not diluted or contaminated by residual intra-luminal fluid. This may have a significant clinical impact in paediatric oncology, where patients frequently require blood transfusions due to the haematological toxicities associated with chemotherapy. It is hoped that these results will impact on hospital policies concerning specified discard volumes taken from CVCs prior to the withdrawal of blood samples for research purposes and routine clinical analysis.

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Organ transplant patients are frequently medicated with triple immunosuppressive therapy that includes both cyclosporin and the corticosteroid, prednisolone. Many of these patients experience gingival overgrowth that necessitates surgical intervention. Chronic dosing with corticosteroids can lead to suppression of the hypothalamic-pituitary axis, and subsequent adrenocortical suppression. To circumvent possible suppression, supplementary steroids are administered to such patients prior to so-called "stressful events". We have examined the need for supplementary steroids in 20 organ transplant patients undergoing gingival surgery under local anaesthesia to correct their drug-induced gingival overgrowth. All patients were operated upon in the first half of the morning. Prior to gingival surgery, resting blood pressure (BP) and serum ACTH concentrations were determined. Immediately before surgery patients received either intravenous hydrocortisone 100 mg or placebo in random, double-blind order. Each patient required 2 gingivectomies and thus acted as their own placebo control. BP was measured at various time points throughout surgery and upto 2 h postoperatively. On completion of surgery, a further blood sample was taken to determine ACTH concentration. There was no significant difference (p>0.05) between placebo and hydrocortisone treatments for BP and ACTH measurements. No patient experienced any symptoms that were suggestive of adrenocortical suppression. One patient did experience postural hypotension prior to gingival surgery, but this is attributed to his antidepressant medication. We can conclude from this study that immunosuppressed organ transplant patients taking the maintenance dose of prednisolone (5-10 mg/day) do not require corticosteroid cover prior to gingival surgery under local anaesthesia. We would however, advocate monitoring of their blood pressure throughout the procedure.

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There is no established treatment for osteoporosis in men, a common and disabling condition the incidence of which is increasing rapidly. We conducted an open study to investigate the efficacy and mode of action of testosterone therapy in eugonadal men with osteoporotic vertebral crush fracture. Twenty-one men, aged 34-73 (mean 58), were treated with intramuscular testosterone esters (Sustanon 250) every 2 weeks for 6 months. Bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry was performed at baseline and 6 months. We also measured biochemical markers of bone turnover, testosterone, estradiol, sex hormone binding globulin (SHBG), and gonadotrophins at baseline and after 3 and 6 months of treatment. Treatment was well tolerated, and side effects were uncommon. Lumbar spine BMD increased by 5% from 0.799 to 0.839 g/cm2 (p < 0.001). All bone markers decreased, indicating that treatment suppressed bone turnover. Although serum osteocalcin levels fell only slightly, there were large reductions in urinary deoxypyridinoline and N-telopeptide (p < 0.05), which were correlated with the increase in spinal BMD. Interpretation of the findings with other markers, such as bone-specific alkaline phosphatase and pyridinoline, was confounded by the wide scatter of values. Serum testosterone increased by 55%, while SHBG decreased by 20%, leading to a rise in free androgen of 90%. Serum estradiol also increased by 45%. The change in spine BMD was significantly correlated with a change in serum estradiol but not with a change in serum testosterone. We therefore conclude that testosterone is a promising treatment for men with idiopathic osteoporosis, acting to suppress bone resorption by a mechanism that may involve estrogen.

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Fasting plasma and/or CSF amino acid levels have been measured in a group of 37 patients with motor neurone disease (MND) and in 35 neurological control patients undergoing lumbar puncture prior to myelography. There were no significant differences in the plasma levels of 22 amino acids between the two groups. In CSF, there was a significant elevation of the glutamate level in the MND patients (P = 0.008). However, the MND group were heterogeneous with regard to CSF glutamate: 19/31 (61%) had levels within the normal range; eight (26%) had levels more than twice the upper limit of normal (> or = 10 mumol/l) and five (16%) had levels more than seven times normal (> or = 30 mumol/l). In a subset of seven MND patients there was a significant inverse correlation (rs = -0.775, P < 0.03) between CSF glutamate levels in life and the density of pre-synaptic glutamate re-uptake sites in the lumbar spinal cord measured in a post-mortem autoradiographic study. A possible interpretation of these findings is that an abnormality of glutamate transport may underlie the increase in CSF glutamate. The identification of a subgroup of MND patients with high CSF glutamate levels may be important in evaluating the clinical response to antiglutamate therapeutic agents.

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Ten patients with biotinidase deficiency were studied. Clinical findings at presentation varied with dermatological signs (dermatitis and alopecia), neurological abnormalities (fits, hypotonia, and ataxia), and recurrent infections being the most common features, although none of these occurred in every case. Biochemically the disease is characterised by metabolic acidosis and organic aciduria. Treatment with biotin results in pronounced, rapid, clinical and biochemical improvement, but some patients have residual neurological damage comprising neurosensory hearing loss, visual pathway defects, ataxia, and mental retardation. The cause of this permanent damage remains obscure and it is not clear if the early introduction of treatment will prevent it.

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The investigation is described of a 62-year-old female patient who presented with severe virilisation; her plasma testosterone concentration was grossly elevated at 37.9 nmol/L. Measurement of plasma androstenedione, dehydroepiandrosterone (DHEA) and DHEA-sulphate, urinary 17-oxosteroids and urinary 'free' cortisol suggested an ovarian source of androgens. An ultrasound scan indicated the presence of an ovarian mass which was removed and classified as a Sertoli-Leydig cell tumour (arrhenoblastoma) combined with a mucinous cystadenoma. Following operation plasma testosterone levels returned to normal. The excessive pre-operative testosterone production appeared to have had little effect on the plasma level of SHBG, since levels remained similar before and after removal of the tumour. Serum LH and FSH levels were higher post-operatively.

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There appear to be at least two underlying aetiologies for combined carboxylase deficiency; firstly, a failure of biotinylation of apocarboxylases due to a mutation of holocarboxylase synthetase (EC 6.3.4.10) which results in an enzyme with a high Km with respect to biotin and secondly, a failure of biotinylation due to a lowered availability of biotin due to biotinidase deficiency (EC 3.5.1.12). In both these disorders secondary defects of all four biotin-dependent carboxylases result which in turn causes the excretion of the metabolites characteristic of the isolated carboxylase deficiencies. In addition, both disorders respond biochemically and clinically to the administration of large amounts of biotin.

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The previously reported method for the estimation of biotinidase (EC 3.5.1.12) is an endpoint colorimetric assay based on the hydrolysis of biotinyl-4-aminobenzoate, followed by diazotization, and is not suitable for our studies of biotinidase. A fluorimetric rate assay of biotinidase which uses a newly synthesized derivative biotinyl-6-aminoquinoline is described here.

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In 34 patients with chronic lymphatic leukaemia (CLL) the lymphocytes have been separated and sized using a C1000 Channelyzer. The modal volume and the volume range of the populations have been obtained and related to clinical stage and mouse red blood cell (MRBC) rosetting capacity. Over 1 year's observation with several estimations per patient there was no convincing drift towards increase in modal volume with deteriorating clinical status. The cell size of the CLL populations could vary from time to time in the same patient. The MRBC rosetting capacity varied greatly between estimations. The findings suggest that in CLL there is an oscillation in cell size in a given patient when tested at intervals.

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