ß-cell specific T-lymphocyte response has a distinct inflammatory phenotype in children with Type 1 diabetes compared with adults.

AIM: To examine the hypothesis that the quality, magnitude and breadth of helper T-lymphocyte responses to ß cells differ in Type 1 diabetes according to diagnosis in childhood or adulthood. METHODS: We studied helper T-lymphocyte reactivity against ß-cell autoantigens by measuring production of the pro-inflammatory cytokine interferon-γ and the anti-inflammatory cytokine interleukin-10, using enzyme-linked immunospot assays in 61 people with Type 1 diabetes (within 3 months of diagnosis, positive for HLA DRB1*0301 and/or *0401), of whom 33 were children/adolescents, and a further 91 were unaffected siblings. RESULTS: Interferon-γ responses were significantly more frequent in children with Type 1 diabetes compared with adults (85 vs 61%; P = 0.04). Insulin and proinsulin peptides were preferentially targeted in children (P = 0.0001 and P = 0.04, respectively) and the breadth of the interferon-γ response was also greater, with 70% of children having an interferon-γ response to three or more peptides compared with 14% of adults (P < 0.0001). Islet ß-cell antigen-specific interleukin-10 responses were similar in children and adults in terms of frequency, breadth and magnitude, with the exception of responses to glutamic acid decarboxylase 65, which were significantly less frequent in adults. CONCLUSIONS: At diagnosis of Type 1 diabetes, pro-inflammatory autoreactivity is significantly more prevalent, focuses on a wider range of targets, and is more focused on insulin/proinsulin in children than adults. We interpret this as indicating a more aggressive immunological response in the younger age group that is especially characterized by loss of tolerance to proinsulin. These findings highlight the existence of age-related heterogeneity in Type 1 diabetes pathogenesis that could have relevance to the development of immune-based therapies.

The prevalence and natural history of pituitary hemorrhage in prolactinoma.

CONTEXT: Incidental pituitary hemorrhage, without full pituitary apoplexy, is a recognized radiological finding, but little information exists on its clinical behavior, with most reports describing surgically treated macroprolactinoma or nonfunctioning adenoma. OBJECTIVE: Our aim was to characterize the prevalence, natural history, and risk factors associated with pituitary hemorrhage in a large clinic prolactinoma population. DESIGN: The design consisted of a retrospective analysis of a clinic population. SETTING: The setting was a tertiary endocrine center in a large teaching hospital. PATIENTS: We studied three hundred sixty-eight patients with prolactinoma. The presence of hemorrhage was documented on magnetic resonance imaging. MAIN OUTCOME MEASURE: The main outcome measures were the prevalence, risk factors, and natural history of pituitary hemorrhage. RESULTS: Pituitary hemorrhage was found in 25 patients, giving an overall prevalence of 6.8%, and was significantly higher in macroprolactinoma (20.3%) compared to microprolactinoma (3.1%, P < .0001). Three patients had classical pituitary apoplexy. The majority of patients in the hemorrhage group had macroprolactinomas (16/25 [64%]) and were women (22/25 [88%]). The proportion of women with macroprolactinoma was higher in the hemorrhage group (14/16 macroprolactinomas [87.5%]) than in the nonhemorrhage group (36/63 macroprolactinomas [57.1%], P = .02). The majority of pituitary hemorrhages (92%) were treated conservatively with dopamine agonist therapy for hyperprolactinemia. Eighty-seven percent of patients had complete resolution of their hemorrhage within 26.6 ± 23.3 (mean ± SD) months. The presence of macroprolactinoma (odds ratio 9.00 [95%CI 3.79-23.88], P < .001) and being female (odds ratio 8.03 [95%confidence interval 1.22-52.95], P = .03) were independently associated with hemorrhage. CONCLUSIONS: These data show that incidental hemorrhage in prolactinoma is not uncommon. It is more likely to occur in macroprolactinoma, where 1 in 5 develop hemorrhage, and is particularly common in women with macroprolactinoma. The majority are asymptomatic and resolve spontaneously.

Assessment of diabetic retinopathy by measuring retina-specific mRNA in blood.

INTRODUCTION: Diabetic retinopathy (DR) is the leading cause of blindness in adults. Early detection and treatment of DR has been shown to reduce the risk of visual loss by as much as 90%. At present, there are no blood tests to detect DR. Previous studies have demonstrated the presence of nucleic acids in blood and raised levels of these markers have been reported in many conditions. The aim of this study was to evaluate the circulating levels of retina-specific mRNA in the assessment of DR. AREAS COVERED: Blood samples were taken into PAXgene Blood RNA tubes from 89 diabetic patients and 19 healthy individuals. A reverse-transcription quantitative real-time PCR assay was used to measure circulating levels of mRNA for rhodopsin (Rho), retinal amine oxidase (RAO) and phosphodiesterase 6C (PDE6C). The results were normalized against mRNA for ß-actin and total RNA. While mRNA for Rho, RAO and ß-actin were detected in 100% of the subjects, PDE6C mRNA was only found in 60% of the individuals and melanopsin mRNA was not detected. When diabetic subjects were divided according to their DR status, significant differences were observed for Rho and RAO-Rho increased while RAO tended to decrease. The area under the curve ROC for Rho and Rho/RAO ratio to differentiate mild or no DR from significant DR (pre-proliferative and proliferative stages) were 0.756 and 0.823, respectively. EXPERT OPINION: These findings suggest that circulating mRNA may be useful in assessing DR.

Factors determining the remission of microprolactinomas after dopamine agonist withdrawal.

BACKGROUND: Withdrawal of dopamine agonist (DA) therapy in the management of microprolactinoma is common practice, but it is unclear which patients are likely to attain long-term remission. OBJECTIVE: To identify predictive factors for long-term remission. DESIGN: Prospective cohort study. PATIENTS: Forty subjects (39 female, aged 24-60 years) with microprolactinoma; all had been normoprolactinaemic on DA therapy for at least 2 years [mean duration of therapy 9 years (range 2-27)]. MEASUREMENTS: A pituitary magnetic resonance imaging (MRI) was performed on 36 (90%) subjects before DA withdrawal. Relapse was defined as prolactin greater than 480 mIU/l (22.8 microg/l) on two occasions. RESULTS: Nine out of 40 (22.5%) subjects were normoprolactinaemic 12 months after DA withdrawal. Amongst the relapse group, 24 of 31 subjects (79.4%) had already relapsed at 3 months. Normalization of MRI prior to DA withdrawal (P = 0.0006) and longer duration of DA treatment (P = 0.032) were significant predictors of remission. Age, pre-treatment prolactin, nadir prolactin, previous failure of DA withdrawal, pregnancy, dose and type of DA were not significant predictors of remission. The nine patients who were in remission at 12 months were then followed up for 58.0 +/- 5.8 months; all remained in remission. CONCLUSIONS: As many as 22.5% of subjects with microprolactinoma remained normoprolactinaemic 12 months after DA withdrawal and these subjects stayed in remission for up to 5 years. Significant predictive factors were normalization of MRI prior to discontinuation, and duration of DA treatment. Our findings support intermittent DA withdrawal after a period of normoprolactinaemia, particularly where MRI appearances have normalized.

Improving prediction of malignancy of cytologically indeterminate thyroid nodules.

BACKGROUND: Fine-needle aspiration (FNA) is essential in the investigation of thyroid nodules. The British Thyroid Association guidelines recommend clarification of whether follicular nodules are probable follicular neoplasms that require surgical excision. This study assessed the value of the subclassification of cytologically indeterminate thyroid nodules into either follicular neoplasms or other pathology. METHODS: The cytology reports of all thyroid FNAs performed between November 2005 and December 2007 at a single institution reported as Thy 3 (follicular lesions) were reviewed. They were reclassified as Thy 3A (probable follicular neoplasm) or Thy 3B (probable non-neoplastic lesion), and subsequently correlated with final clinical outcome to determine the predictive value of this subclassification. RESULTS: Forty-nine specimens were categorized as Thy 3A and 55 as Thy 3B. Of excised lesions, 14 (29 per cent) of 48 Thy 3A and 4 (10 per cent) of 42 Thy 3B nodules were malignant. If Thy 3A were to predict malignancy and Thy 3B benign disease, the sensitivity of the classification was 88 per cent, with a specificity of 55 per cent and negative predictive value of 91 per cent. CONCLUSION: Subclassification of Thy 3 nodules into Thy 3A and Thy 3B improves the assessment of risk for thyroid malignancy.

Thomas Addison's disease after 154 years: modern diagnostic perspectives on an old condition.

Thomas Addison was first to describe adrenocortical failure in 1855. Despite advances in the treatment of this condition, the diagnosis is still often delayed and sometimes missed with potentially fatal consequences. From the same institution where Thomas Addison performed his original autopsy studies, we present four recent cases highlighting the wide clinical spectrum and discuss how modern biochemical and immunological tests could be utilized in early diagnosis and aetiological classification.

Circulating nucleic acids in the assessment of endogenous growth hormone production.

There is growing concern about the use of recombinant human growth hormone (rhGH) by individuals taking part in competitive sports. Although rhGH is banned by the international organizations, the detection of GH doping is difficult. We postulated that rhGH will suppress endogenous GH production, which can be assessed by the measurement of mRNA for GH and growth hormone-releasing hormone (GHRH). In order to prove this concept, we undertook a pilot study to examine whether circulating nucleic acids are useful in the detection of endogenous GH production. Blood samples were collected into PAXgene tubes from 37 healthy controls and 12 acromegalic patients. RNA was extracted from the samples, cDNA was obtained, and the quantities of mRNA for GH and GHRH were measured using real-time PCR. In acromegalic patients, median mRNA concentration for GHRH (corrected for beta-actin mRNA) was 30.7 times lower than in controls (median delta C(T)) value of -0.128 versus 3.927, P < 0.001). There was a significant correlation between serum IGF-1 SD score and mRNA for GHRH (r= 0.407). In acromegalic patients, mRNA for GH was significantly higher than in controls (median values of -4.694 versus -0.044, P < 0.05). As GH production is known to decline with age, we also examined mRNA for GH and GHRH according to age subgroups. Both markers were significantly lower in the older age group (>50 years) compared to the younger age group (<34 years). These results show that mRNA for GH and GHRH can be detected in the peripheral circulation and raises the possibility of using these markers in the detection of exogenously administered GH.

Measurement of circulating neuron-specific enolase mRNA in diabetes mellitus.

In this study we measured the levels of neuron-specific enolase mRNA as a possible marker of diabetic neuropathy. Blood samples were collected from healthy controls (n= 26), diabetic controls (no known neuropathy or retinopathy) (n= 22), and diabetics with clinically diagnosed neuropathy (n= 24) into PAXgene blood RNA tubes. mRNA was extracted, reverse-transcribed to cDNA, and measured by real-time quantitative PCR. Enolase mRNA levels were normalized by the simultaneous measurement of beta-actin mRNA. The results showed that the enolase mRNA was significantly (P= 0.002) higher in the diabetic control (median = 0.018; range = 0.006-0.037) group compared to healthy subjects (median = 0.0086; range = 0.0016-0.039). However, the diabetic neuropathy group showed lower enolase levels (median = 0.0067; range = 0.0025-0.017) compared to both healthy subjects (P= 0.06) and diabetic controls (P < 0.001). In the diabetic neuropathy group patients with preproliferative (median = 0.01; range = 0.008-0.017) or proliferative retinopathy (median = 0.011; range = 0.007-0.015) had significantly (P= 0.001) higher enolase mRNA compared to patients with background retinopathy (media = 0.004; range = 0.0025-0.0092). It is concluded that levels of enolase mRNA are decreased in diabetic neuropathy and this molecular marker may also be useful in differentiating early from advanced eye disease in those diabetics diagnosed with neuropathy.

Retina-specific mRNA in the assessment of diabetic retinopathy.

In a previous study we demonstrated the presence and diagnostic usefulness of circulating rhodopsin mRNA in the assessment of diabetic retinopathy (DR). In the present study we investigated three further retina-specific markers in blood to determine their suitability as markers of DR. The markers were RPE65, retinoschisin, and melanopsin. Whole blood was collected from diabetic patients and healthy controls into PAXgene Blood RNA tubes and RNA was extracted using the PAXgene Blood RNA System. Quantitative real-time PCR was used to quantify mRNA for RPE65, retinoschisin, and melanopsin. beta-actin mRNA was used for normalization. RPE65, retinoschisin, and beta-actin mRNA were detected in 100% of subjects; melanopsin was not detected in either controls or diabetic patients. Circulating RPE65 mRNA concentration was 63% higher in diabetic patients than in healthy individuals (P= 0.019), whereas retinoschisin showed no change between the two groups. Compared with healthy controls, circulating RPE65 mRNA concentration was higher in diabetics with no retinopathy (30%; P= NS), background DR (93%; P= 0.01), preproliferative DR (20%; P= NS), and proliferative DR (107%; P= 0.004). Compared with diabetics with no retinopathy, levels of RPE65 mRNA were also significantly higher (60%) in the presence of proliferative DR (P= 0.029). In contrast, levels of retinoschisin mRNA were lower in background DR (34%; P= 0.033), preproliferative DR (43%; P= 0.026), and proliferative DR (47%; P= 0.038) compared to that in diabetics without retinopathy. We conclude that not all retina-specific mRNA species are detectable in circulation (e.g., melanopsin). This may be related to differences in expression levels for the individual markers. Both RPE65 and retinoschisin were detectable and demonstrated contrasting trends in diabetics with and without retinopathy. In combination with rhodopsin, RPE65, and retinoschisin, mRNA may offer a useful tool in developing a blood test for DR.

Detection of growth hormone abuse in sport.

OBJECTIVE: To develop a test for GH abuse in sport. DESIGN: A double blind placebo controlled study of one month's GH administration to 102 healthy non-competing but trained subjects. Blood levels of nine markers of GH action were measured throughout the study and for 56 days after cessation of GH administration. Blood samples were also taken from 813 elite athletes both in and out of competition. RESULTS: GH caused a significant change in the nine measured blood markers. Men were more sensitive to the effects of GH than women. IGF-I and N-terminal extension peptide of procollagen type III were selected to construct formulae which gave optimal discrimination between the GH and placebo groups. Adjustments were made to account for the fall in IGF-I and P-III-P with age and the altered distribution seen in elite athletes. Using a cut-off specificity of 1:10,000 these formulae would allow the detection of up to 86% of men and 60% of women abusing GH at the doses used in this study. CONCLUSIONS: We report a methodology that will allow the detection of GH abuse. This will provide the basis of a robust and enforceable test identifying those who are already cheating and provide a deterrent to those who may be tempted to do so.

18Flurodeoxyglucose positron emission tomography in the localization of ectopic ACTH-secreting neuroendocrine tumours.

OBJECTIVE: Neuroendocrine tumours (NET) are a rare cause of Cushing's syndrome. These tumours can be very small and therefore difficult to identify. Current localization techniques include CT, MRI and radioisotope scanning, but in a proportion of cases the NET remains occult. Positron emission tomography (PET) scanning, is a relatively new imaging modality that is increasingly used to detect and monitor lesions with high metabolic activity. We report on the use of PET scanning in the evaluation of the ectopic ACTH syndrome. PATIENTS: Three patients with ectopic ACTH-dependent Cushing's syndrome with varying difficulty in NET localization are included in the report. MEASUREMENT: Positron emission tomography scanning using 18flurodeoxyglucose (FDG) identifies tissue with high metabolic activity. 18FDG-PET scanning was used in each of these patients and the imaging is presented along with biochemical data. RESULTS: In each case the NET was easily identified using 18FDG-PET, aiding clinical decision making and therapeutic outcome. A cure was identified by clinical resolution of symptoms and undetectable ACTH levels postsurgery. CONCLUSIONS: 18FDG-PET assisted in localizing small metabolically active NETs, suggesting this imaging modality may have a useful role in identifying NET causing Cushing's syndrome as a result of ectopic ACTH production.

Gender differences in growth hormone response to exercise before and after rhGH administration and the effect of rhGH on the hormone profile of fit normal adults.

OBJECTIVES: Exercise is a potent physiological stimulus of GH secretion. We hypothesized that exogenous recombinant human growth hormone (rhGH) administration through an increase in GH and IGF-I levels would blunt the GH response to exercise. The aim of the study was to examine and compare the impact of rhGH on the exercise-induced GH response in healthy normal men and women. DESIGN AND MEASUREMENTS: Sixty-nine subjects (36 men, 33 women) were randomized to receive low-dose rhGH (0.1 U/kg/day), high dose rhGH (0.2 U/kg/day), or placebo. Subjects were matched for age (24 +/- 3.1), and body mass index (BMI). rhGH was given as a single subcutaneous (s.c.) injection for the first 28 days. All subjects exercised to exhaustion (maximal oxygen consumption--VO2max) before rhGH treatment (Test 1), and on day 28 (Test 2). GH was measured before exercise (time 0), immediately after exercise (time 0') and at 15, 30, 60, 90 and 120 min postexercise. Baseline IGF-I levels were measured before exercise on days 0 and 28. RESULTS: Baseline IGF-I levels showed no gender differences (42.3 women vs. 38.8 nmol/l men) but basal GH values were higher in women (9.9 vs. 1.8 mU/l, P < 0.001). The areas under the GH response curve, for Test 1 were similar in men and women. Peak GH values were higher in women than men (37.9 vs. 23.5 mU/l, but this did not quite reach statistical significance (P = 0.055). In men, administration of rhGH resulted in a significant increase in IGF-I levels over the basal state in both the LD and HD groups (P < 0.0001). In women, the increase in lGF-I levels reached significance only in the HD group (P < 0.0001). On day 28, GH secretion in response to exercise was calculated from the areas under the GH response curve correcting for an exogenous rhGH component (delta AUC). In men, the delta AUC, for Test 2 were similar in all three groups. In women, the delta AUC was higher in the placebo group, than in the HD group (P < 0.02). Free T4 levels decreased significantly in men, and free T3 increased in both men and women, in HD group after the rhGH administration. TSH levels were suppressed only in women. No changes in sex hormones were found in men or women in any of the treatment groups. Conclusions In terms of IGF-I, men are more responsive to rhGH treatment than women. In addition, as men, but not women, were able to overcome the negative feedback control of the elevated IGF-I levels, it seems that exercise may be a more robust stimulus to GH release in men compared to women.

Lymphocytic hypophysitis: spontaneous resolution on MRI with progression of endocrine defect.

Lymphocytic hypophysitis is an uncommon condition that typically occurs during the last trimester of pregnancy or in the postpartum period. Presentation is of an anterior pituitary mass with varying degrees of pituitary dysfunction. We present a case in which there was dramatic resolution of the pituitary lesion on sequential MRI scanning. Despite this apparent resolution, however, the patient continues to have significant pituitary dysfunction.

Self-monitoring in Type 2 diabetes mellitus: a meta-analysis.

AIMS: Self-monitoring of blood or urine glucose is widely used by subjects with Type 2 diabetes mellitus. This study evaluated the effectiveness of the technique at improving blood glucose control through a systematic review and meta-analysis. METHODS: Randomized controlled trials were identified that compared the effects of blood or urine glucose monitoring with no self-monitoring, or blood glucose self-monitoring with urine glucose self-monitoring, on glycated haemoglobin as primary outcome in Type 2 diabetes. RESULTS: Eight reports were identified. These were rated for quality and data were abstracted. The mean (SD) quality score was 15.0 (1.69) on a scale ranging from 0 to 28. No study had sufficient power to detect differences in glycated haemoglobin (GHb) of less than 0.5%. One study was excluded because it was a cluster randomized trial of a complex intervention and one because fructosamine was used as the outcome measure. A meta-analysis was performed using data from four studies that compared blood or urine monitoring with no regular monitoring. The estimated reduction in GHb from monitoring was -0.25% (95% confidence interval -0.61 to 0.10%). Three studies that compared blood glucose monitoring with urine glucose monitoring were also combined. The estimated reduction in GHb from monitoring blood glucose rather than urine glucose was -0.03% (-0.52 to 0.47%). CONCLUSIONS: The results do not provide evidence for clinical effectiveness of an item of care with appreciable costs. Further work is needed to evaluate self-monitoring so that resources for diabetes care can be used more efficiently.

Novel hepatoselective insulin analog: studies with a covalently linked thyroxyl-insulin complex in humans.

OBJECTIVE: To test whether a thyroxyl-insulin analog with restricted access to receptor sites in peripheral tissues displays relative hepatoselectivity in humans. RESEARCH DESIGN AND METHODS: Five normal human subjects received a subcutaneous bolus injection of either N(alphaBl) L-thyroxyl-insulin (Bl-T4-Ins) or NPH insulin in random order. Insulin kinetics, relative effects on hepatic glucose production, and peripheral glucose uptake were studied using euglycemic clamp and stable isotope [D-6,6-(2)H2]glucose) dilution techniques. Blood samples were taken for the determination of total immunoreactive insulin/analog concentrations and for liquid chromatography to assess the protein binding of the analog in the circulation. RESULTS: After subcutaneous administration, Bl-T4-Ins was well tolerated and rapidly absorbed. The analog had a long serum half-life and was highly protein bound (approximately 86%). Its duration of action, as judged by the duration of infusion of exogenous glucose to maintain euglycemia, was similar to that of NPH insulin. The effect of the analogs on hepatic glucose production was similar to that of NPH insulin, indicating equivalent hepatic potency. The analog demonstrated less effect on peripheral glucose uptake than NPH insulin (P = 0.025), had no effect on metabolic clearance rate of glucose, and exhibited a reduced capacity to inhibit lipolysis (P < 0.05). CONCLUSIONS: When injected subcutaneously into normal human subjects, Bl-T4-Ins is well tolerated, quickly absorbed, and highly protein bound, resulting in a long plasma halflife. This analog appears to have a hepatoselective action, and, therefore, has the potential to provide more physiological insulin action than the insulin preparations currently used.

Growth hormone (GH) effects on bone and collagen turnover in healthy adults and its potential as a marker of GH abuse in sports: a double blind, placebo-controlled study. The GH-2000 Study Group.

The effects of GH on bone remodeling in healthy adults have not been systematically investigated. An analysis of these effects might provide insights into GH physiology and might yield data useful for the detection of GH doping in sports. The aim of this study was to evaluate the effects of GH administration on biochemical markers of bone and collagen turnover in healthy volunteers. Ninety-nine healthy volunteers of both sexes were enrolled in a multicenter, randomized, double blind, placebo-controlled study and assigned to receive either placebo (40 subjects) or recombinant human GH (0.1 IU/kg day in 29 subjects and 0.2 IU/kg x day in 30 subjects). The treatment duration was 28 days, followed by a 56-day wash-out period. The biochemical markers evaluated were the bone formation markers osteocalcin and C-terminal propeptide of type I procollagen, the resorption marker type I collagen telopeptide, and the soft tissue marker procollagen type III. All variables increased on days 21 and 28 in the two active treatment groups vs. levels in both the baseline (P < 0.01) and placebo (P < 0.01) groups. The increment was more pronounced in the 0.2 IU/kg-day group and remained significant on day 84 for procollagen type III (from 0.53 +/- 0.13 to 0.61 +/- 0.14 kU/L; P < 0.02) and osteocalcin (from 12.2 + 2.9 to 14.6 +/- 3.6 UG/L; P < 0.02), whereas levels of C-terminal propeptide of type I procollagen and type I collagen telopeptide declined after day 42 and were no longer significantly above baseline on day 84 (from 3.9 +/- 1.2 to 5.1 +/-1.5 microg/L and from 174 +/- 60 to 173 +/- 53 microg/L, respectively). Gender-related differences were observed in the study; females were less responsive than males to GH administration with respect to procollagen type III and type I collagen telopeptide (P < 0.001). In conclusion, exogenous GH administration affects the biochemical parameters of bone and collagen turnover in a dose- and gender-dependent manner. As GH-induced modifications of most markers, in particular procollagen type III and osteocalcin, persist after GH withdrawal, they may be suitable markers for detecting GH abuse.