Images from the surface of asteroid Ryugu show rocks similar to carbonaceous chondrite meteorites

The near-Earth asteroid (162173) Ryugu is a 900-m-diameter dark object expected to contain primordial material from the solar nebula. The Mobile Asteroid Surface Scout (MASCOT) landed on Ryugu's surface on 3 October 2018. We present images from the MASCOT camera (MASCam) taken during the descent and while on the surface. The surface is covered by decimeter- to meter-sized rocks, with no deposits of fine-grained material. Rocks appear either bright, with smooth faces and sharp edges, or dark, with a cauliflower-like, crumbly surface. Close-up images of a rock of the latter type reveal a dark matrix with small, bright, spectrally different inclusions, implying that it did not experience extensive aqueous alteration. The inclusions appear similar to those in carbonaceous chondrite meteorites.

Lessons learned with Bone Health TeleECHO: making treatment decisions when guidelines conflict

Clinical practice guidelines provide helpful information for managing patients with metabolic bone disease. Good guidelines are based on the best available medical evidence; however, guidelines from different societies can conflict. Additionally, it is not possible for a guideline to anticipate the vast variability of circumstances, comorbidities, previous medical experiences, cultural differences, and preferences in real-world patients. Bone Health TeleECHO is a strategy for sharing knowledge on the care of patients with skeletal diseases through ongoing interactive videoconferences. We report three cases based on those presented at Bone Health TeleECHO, where, through discussion, treatment outside of commonly used guidelines was ultimately recommended. Guidelines developed by different organizations may provide "evidence-based" or "informed" recommendations which do not account for the variability of clinical circumstances encountered in the care of individual patients. This highlights the importance of Bone Health TeleECHO, where healthcare professionals can share knowledge, individualize treatment decisions, and improve patient care.Learning objectives At the end of this activity participants should be able to:• Distinguish between the onset and off of bisphosphonates versus other medications used in the prevention and treatment of osteoporosis and how this affects choice of a "drug holiday."• Understand the limitations of clinical practices guidelines in the care of an individual patient and how interactive video conferencing can assist with decision making.• Recognize that patients treated with glucocorticoids at high risk for fracture can benefit from more aggressive interventions for osteoporosis.

Examining the treatment gap and risk of subsequent fractures among females with a fragility fracture in the US Medicare population

Our aim was to evaluate the gap in osteoporosis treatment and the impact of osteoporosis treatment on subsequent fragility fractures. We found osteoporosis medication use lowered risk of subsequent fractures by 21% and that black race, higher CCI scores, dementia, and kidney diseases reduced the likelihood of osteoporosis medication use.

INTRODUCTION

The goal of this study was to evaluate the predictors of osteoporosis medication use and compare the risk of fragility fractures within 1 year of a fragility fracture between osteoporosis treated and untreated women.

METHODS

We conducted a retrospective, observational cohort study using the national Medicare database. Elderly women (≥65 years) who were hospitalized or had an outpatient/ER service for fragility fracture between January 1, 2011 and December 31, 2011 were included. The outcomes of interest were the correlates of and time-to-osteoporosis medication use and risk of a subsequent fracture within 12 months for treated and untreated women. Cox regression was used to evaluate the predictors of treatment use and the risk of fracture based on treatment status.

RESULTS

Women (28,722) (27.7%) were treated with osteoporosis medication within 12 months of index fracture, and 74,979 (72.2%) were untreated. A number of patient characteristics were associated with a reduced likelihood of osteoporosis medication use, including black race, higher Charlson comorbidity index scores, presence of dementia, and kidney diseases in the baseline. The predictor most strongly and positively associated with osteoporosis medication use after fracture was osteoporosis medication use before fragility fracture (HR = 7.87; 95% CI 7.67-8.07). After adjusting for baseline characteristics, osteoporosis medication use lowered the risk of subsequent fractures by 21% (HR = 0.79, 95% CI 0.75-0.83) over 12 months compared to women without treatment.

CONCLUSIONS

Demographics and clinical characteristics were strong predictors of osteoporosis medication use. In the US Medicare population, osteoporosis treatment significantly reduced the risk of fragility fractures.

Patients with prior vertebral or hip fractures treated with teriparatide in the Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) observational study

SUMMARY

In patients in the Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) observational study with and without a prior vertebral or hip fracture, the incidence of nonvertebral fractures was lower with >6 months of teriparatide treatment than during the first 6 months.

INTRODUCTION

Clinical evidence on the effect of teriparatide in patients with prior fracture is limited. In the DANCE observational study, the incidence of nonvertebral fragility fractures (NVFX) decreased significantly in patients receiving teriparatide for >6 months (6-24 months) versus >0 to ≤6 months (reference period).

METHODS

We performed a post hoc analysis to assess the effect of teriparatide 20 μg/day in patients who entered DANCE with prior vertebral or hip fractures. The incidence of patients experiencing a NVFX for four 6-month intervals during and after treatment was compared with the reference period.

RESULTS

Overall, 4085 patients received ≥1 dose of teriparatide. Of 3720 with sufficient data for efficacy analysis, 692 had prior vertebral fracture, including 179 with previous kyphoplasty/vertebroplasty; 290 had prior hip fracture. These patients were older, and those with prior vertebral fractures had more comorbid conditions at baseline than those without prior vertebral fractures. The incidence of patients experiencing NVFX declined over time in all patient groups. The fracture incidence rate declined 49 and 46%, respectively, in patients with and without prior vertebral fracture and was 63 and 46% lower in patients with previous kyphoplasty/vertebroplasty and without prior vertebral fracture. NVFX declined 43 and 48% in patients with and without prior hip fracture. The reduced incidence over time was consistent in the subgroups (all interaction p values >0.05). Patients with prior fracture were more likely to experience serious adverse events.

CONCLUSION

The incidence of NVFX decreased over time in patients receiving teriparatide in DANCE regardless of prior fracture status.

Association between teriparatide adherence and healthcare utilization and costs in real-world US kyphoplasty/vertebroplasty patients

The objective of this study was to examine the association between teriparatide adherence and healthcare utilization and costs in real-world US kyphoplasty/vertebroplasty (KV) patients. Among KV patients newly initiating teriparatide, significantly increased pharmacy costs associated with high teriparatide adherence were offset by significantly lower inpatient utilization and medical costs.

INTRODUCTION

This study seeks to examine the association between teriparatide adherence and healthcare utilization/costs in real-world US KV patients.

METHODS

Identified patients from a large US administrative claims database were aged 50+ with KV from 1/1/2002-12/31/2010 (first observed KV = index). Included individuals had 6+ months of pre-index continuous enrollment and no pre-index teriparatide, cancer, or Paget's disease. Follow-up period for patients initiating teriparatide was ≤36 months post-index. Three teriparatide adherence cohorts were constructed using the proportion of days covered (PDC) during the follow-up period: low (PDC ≤ 0.5), medium (PDC >0.5-≤ 0.8), and high (PDC >0.8). Repeated KV admissions, any inpatient admission, number of inpatient admissions, and per-patient-per-month (PPPM) inpatient, outpatient, pharmacy, and total costs were compared between cohorts. The associations between teriparatide adherence and healthcare utilization/costs were examined using multivariable regression models, adjusting for patient demographics and clinical characteristics.

RESULTS

Included were 1,568 patients (mean age, 75 years; 82% female): 403 (26%) had low adherence, 382 (24%) medium, and 783 (50%) high. After multivariable adjustment, high adherence was significantly associated with the lowest PPPM inpatient (low = $1,287; medium = $1,005; high = $678) and outpatient (low = $1,464; medium = $1,244; high = $1,077) medical costs, but with increased pharmacy costs (low = $752; medium = $1,159; high = $1,616; all P < 0.05), leading to similar total costs (low = $3,344; medium = $3,376; high = $3,351) between cohorts; high adherence was also significantly associated with the lowest odds of repeated KV admission, any inpatient admission, and number of inpatient admissions (all P < 0.05).

CONCLUSIONS

Among KV patients initiating teriparatide, significantly increased pharmacy costs associated with high teriparatide adherence were offset by significantly lower inpatient utilization and medical costs.

The Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) study: 2-year nonvertebral fragility fracture results

This observational study evaluated the occurrence of nonvertebral fragility fractures (NVFX) in over 4,000 men and women with osteoporosis treated with teriparatide (TPTD). The incidence of new NVFX decreased for patients receiving TPTD treatment for greater than 6 months. No new significant safety findings were observed in this large trial.

INTRODUCTION

The Direct Assessment of Nonvertebral Fractures in Community Experience (DANCE) study evaluated the occurrence of NVFX in patients receiving TPTD for osteoporosis in a real-world setting.

METHODS

DANCE is a multicenter, prospective, observational trial that examined the long-term effectiveness of TPTD in men and women with osteoporosis whom study physicians judged to be suitable for TPTD therapy. Patients received 20 μg TPTD per day by subcutaneous injection for up to 24 months and were followed for 24 months after treatment cessation. The incidence of patients experiencing a new NVFX, defined as a fracture associated with low trauma, was evaluated during four 6-month periods in both the treatment and cessation phases with >0 to ≤6 months serving as the reference. We also observed the spectrum and occurrence of serious adverse events.

RESULTS

Of the 4,167 patients enrolled, 4,085 took one or more doses of TPTD (safety population); 3,720 were included in the efficacy analysis. The incidence of patients experiencing a NVFX was 1.42, 0.91, 0.70, and 0.81 % for the four treatment periods, respectively, and 0.80, 0.68, 0.33, and 0.33 % for the four periods after treatment cessation. Differences for each period were statistically significant compared with the reference period (first 6-month interval, each p < 0.05). No new significant safety findings were observed.

CONCLUSIONS

In this study, the incidence of NVFX decreased for patients receiving TPTD for all three treatment periods >6 months compared to 0 to ≤6 months, and this trend persisted throughout the cessation phase. TPTD was generally well tolerated.

Nonanolides of natural origin: structure, synthesis, and biological activity

Naturally occurring nonanolides (synonym decanolides) are a large family of secondary metabolites with an interesting 10- membered macrolide subunit. Metabolites of the nonanolide family have been found to have various biological activities, including cytotoxic, phytotoxic, antimalarial, antifungal, antibacterial, and antimicrofilament activities. An early review of the chemistry and bioactivity of nonanolides was presented in 1996, covering the literature published between 1975 and 1995. During the past decades, the broad spectrum of bioactivity and the intriguing structure of the medium-sized ring in nonanolide analogues have continuously drawn the attention of biologists and natural product and synthetic chemists, resulting in a great number of publications. This review summarizes in whole the recent progress in the field of the nonanolides of natural origin, aiming to give the readers a brief view of the compounds, concerning their natural occurrence, structural elucidation, biological activities, total synthesis, and structure-activity relationships. The article covers the literature published in the period from the beginning of 1996 to July 2011.

Gender differences for initiating teriparatide therapy: baseline data from the Direct Assessment of Nonvertebral Fracture in the Community Experience (DANCE) study

The prospective, observational Direct Assessment of Nonvertebral Fracture in the Community Experience (DANCE) study shows that, among patients with risk factors for osteoporosis, women are more likely to be screened and to receive appropriate treatment than men. There needs to be greater awareness that osteoporosis affects both men and women.

INTRODUCTION

The prospective, observational DANCE study evaluated teriparatide use in the mainland USA and Puerto Rico in patients with osteoporosis in a community setting. This analysis compares baseline characteristics of women and men that may contribute to differences in initiation of teriparatide therapy.

METHODS

Investigators prescribed teriparatide 20 μg/day subcutaneous injection for ≤24 months to 3,698 patients (3,342 women, 356 men) whom they considered appropriate candidates for therapy. Study entry was guided by product labeling. Specific timing and frequency of office visits were not mandated. Treatment decisions were based on the clinical judgment of study investigators and local standards of care.

RESULTS

At baseline, similar proportions of women and men had prior fragility fractures (57% and 59%, respectively) and comorbid conditions that increase fracture risk (83% and 84%, respectively). Women were older than men (mean age 68 vs. 65 year; P < 0.0001) and more likely to have received prior osteoporosis therapy (88% vs. 62%; P < 0.0001). Investigators prescribed teriparatide more often for women than men based on general frailty (21% vs. 16%; P = 0.0151), low body mass index (17% vs. 10%; P = 0.0005), and an inadequate response (58% vs. 36%; P < 0.0001) or intolerance to previous therapy (23% vs. 12%; P < 0.0001). Chronic glucocorticoid therapy was the reason investigators cited most frequently for initiating therapy more often in men than in women (17% vs. 10%; P < 0.0001)

CONCLUSIONS

These results suggest that patients' gender may influence the reasons physicians initiate teriparatide therapy in a community setting.

Teriparatide versus alendronate for treating glucocorticoid-induced osteoporosis: an analysis by gender and menopausal status

SUMMARY

The effects of teriparatide versus alendronate were compared by gender and menopausal status in patients with glucocorticoid-induced osteoporosis. At 18 months, increases in lumbar spine BMD were significantly greater in the teriparatide versus alendronate group in postmenopausal women (7.8% versus 3.7%, p < 0.001), premenopausal women (7.0% versus 0.7%, p < 0.001), and men (7.3% versus 3.7%, p = 0.03).

INTRODUCTION

In patients with glucocorticoid-induced osteoporosis (GIO), teriparatide significantly increased bone mineral density (BMD) and decreased vertebral fractures compared with alendronate. We examined effects of teriparatide versus alendronate by gender and menopausal status.

METHODS

This was a multicenter, randomized, double-blind study of teriparatide 20 microg/day versus alendronate 10 mg/day in patients with GIO (277 postmenopausal women, 67 premenopausal women, 83 men). Primary outcome was change in lumbar spine BMD. Secondary outcomes included change in hip BMD, change in bone biomarkers, fracture incidence, and safety.

RESULTS

At 18 months, mean percent increases from baseline in lumbar spine BMD were significantly greater in the teriparatide versus alendronate group in postmenopausal women (7.8% versus 3.7%, p < 0.001), premenopausal women (7.0% versus 0.7%, p < 0.001), and men (7.3% versus 3.7%, p = 0.03). Radiographic vertebral fractures occurred in one teriparatide (one postmenopausal) and ten alendronate patients (six postmenopausal, four men), and nonvertebral fractures occurred in 12 teriparatide (nine postmenopausal, two premenopausal, one man) and eight alendronate patients (six postmenopausal, two men). The proportion of patients reporting adverse events in teriparatide versus alendronate groups was consistent across subgroups.

CONCLUSION

Among men and pre- and postmenopausal women with GIO, lumbar spine BMD increased more in patients receiving teriparatide compared with alendronate.

Neonatology/Paediatrics - Guidelines on Parenteral Nutrition, Chapter 13

There are special challenges in implementing parenteral nutrition (PN) in paediatric patients, which arises from the wide range of patients, ranging from extremely premature infants up to teenagers weighing up to and over 100 kg, and their varying substrate requirements. Age and maturity-related changes of the metabolism and fluid and nutrient requirements must be taken into consideration along with the clinical situation during which PN is applied. The indication, the procedure as well as the intake of fluid and substrates are very different to that known in PN-practice in adult patients, e.g. the fluid, nutrient and energy needs of premature infants and newborns per kg body weight are markedly higher than of older paediatric and adult patients. Premature infants <35 weeks of pregnancy and most sick term infants usually require full or partial PN. In neonates the actual amount of PN administered must be calculated (not estimated). Enteral nutrition should be gradually introduced and should replace PN as quickly as possible in order to minimise any side-effects from exposure to PN. Inadequate substrate intake in early infancy can cause long-term detrimental effects in terms of metabolic programming of the risk of illness in later life. If energy and nutrient demands in children and adolescents cannot be met through enteral nutrition, partial or total PN should be considered within 7 days or less depending on the nutritional state and clinical conditions.

Lipid emulsions - Guidelines on Parenteral Nutrition, Chapter 6

The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within ≤7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (α-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25–40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7–1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels >400 mg/dl (>4.6 mmol/l) and interruption of lipid infusion at levels >1000 mg/dl (>11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints.

Cellular immunity in renal diseases

Cellular immune reactivity was studied in 78 patients with various forms of renal disease by skin testing with four recall antigens and a lymphocyte transformation test with tuberculin PPD and leucoagglutinin. Patients with S-creatine greater than or equal to 230 micromol/l as well as those with chronic pyelonephritis who had S-creatinine values below 230 micromol/l had significantly lower skin reactions than the controls to streptokinase-streptodornase, parotitis and PPD. Glomerulonephritic patients with S-creatinine values below 230 micromol/l had normal skin reactivity. Lymphocyte transformation tests showed decreased reactivity only in patients with S-creatinine level greater than or equal to 230 micromol/l. The results suggest an association of chronic pyelonephritis with a defective efferent, nonspecific arm of cellular immunity.

WITHDRAWN: National Guidelines. Guidelines on Parenteral Nutrition from the German Society for Nutritional Medicine (DGEM) - Part 1

This article has been withdrawn at the request of the authors and Editor. The publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Antimicrobial activity of the methanolic extract and of the chemical constituents isolated from Newbouldia laevis

The methanolic extract (NLB) and ten compounds isolated from the root bark of Newbouldia laevis Seem, namely chrysoeriol (1), newbouldiaquinone (2), 2-acetylfuro-1,4-naphthoquinone (3), 2-hydroxy-3-methoxy-9,10-dioxo-9,10-dihydroanthracene-1-carbaldehyde (4), lapachol (5), beta-sitosterol-3-O-beta-D-glucopyranoside (6), oleanolic acid (7), canthic acid (8) newbouldiamide (9) and 2-(4-hydroxyphenyl)-ethyltrioctanoate (10), were tested for in vitro antimicrobial activity. Twenty one microorganisms belonging to six Gram-positive and twelve Gram-negative bacterial species as well as three yeasts from Candida species were tested for their susceptibility to NLB and the pure isolated compounds based on the Agar Hole Diffusion test and the Liquid Dilution method. The Hole Diffusion assay indicated that NLB and compound 7 were active against all tested pathogens while other compounds showed selective activity with the antimicrobial spectra varying from 76% (compound 10) to 95 % (compound 6). Minimal inhibitory concentrations (MIC) also illustrated the important antimicrobial activity of NLB and of the isolated compounds. MIC values obtained varied from 9.76 to 312.50 microg/ml for NLB, and 0.038 to 9.76 microg/ml for pure compounds against most of the tested microorganisms. The antimicrobial activities of compounds 2, 4 and 9 are described here extensively for the first time. The results indicate a promising basis for the use of Newbouldia laevis and some of its active principles in the treatment of infectious diseases.

Iodine deficiency activates antioxidant genes and causes DNA damage in the thyroid gland of rats and mice

Because thyroid nodules are frequent in areas with iodine deficiency the aim of this study was to characterise molecular events during iodine deficiency that could explain mutagenesis and nodule formation. We therefore studied gene expression of catalytic enzymes prominent for H(2)O(2) detoxification and antioxidative defence, quantified DNA oxidation and damage as well as spontaneous mutation rates (SMR) in mice and rats fed an iodine controlled diet. Antioxidative enzymes such as superoxide dismutase 3, glutathione peroxidase 4 and the peroxiredoxins 3 and 5 showed increased mRNA expression, which indicates increased radical burden that could be the cause of additional oxidized base adducts found in thyroidal genomic DNA in our experiments of iodine deficiency. Furthermore, the uracil content of thyroid DNA was significantly higher in the iodine-deficient compared to the control group. While SMR is very high in the normal thyroid gland it is not changed in experimental iodine deficiency. Our data suggest that iodine restriction causes oxidative stress and DNA modifications. A higher uracil content of the thyroid DNA could be a precondition for C-->T transitions often detected as somatic mutations in nodular thyroid tissue. However, the absence of increased SMR would argue for more efficient DNA repair in response to iodine restriction.

Deficiency of the autoimmune regulator AIRE in thymomas is insufficient to elicit autoimmune polyendocrinopathy syndrome type 1 (APS-1)

Thymomas are thymic epithelial neoplasms, associated with a variety of autoimmune disorders (especially myasthenia gravis), that apparently result from aberrant intra-tumourous thymopoiesis and export of inefficiently tolerized T-cells to the periphery. The autoimmune regulator (AIRE) drives the expression of self-antigens in the thymic medulla and plays an essential role in 'central' tolerance in both humans and mice. However, while inactivating AIRE mutations result in the 'autoimmune polyendocrinopathy syndrome type 1' (APS-1), its major features are not well reproduced in AIRE-knock-out mice. Therefore, alternative human disease scenarios with concomitant AIRE deficiency may be valuable tools to test conclusions drawn from mouse models. Here we show, in a large series, that approximately 95% of thymoma patients are 'chimeric'; expression of AIRE and major AIRE-related autoantigens (eg insulin) were undetectable in their tumours but maintained in their remnant thymic tissue and lymph nodes. Notably, despite the AIRE-deficient thymopoiesis in thymomas, disorders and autoantibodies typical of APS-1 were distinctly uncommon in these patients. The one striking similarity was in the recently observed neutralizing anti-type I interferon (IFN) antibodies, which are found at diagnosis in 100% of patients with APS-1 and in approximately 60% of patients with thymomas, as we show here. We conclude that APS-1 type autoantigens must be protected from autoimmunity by mechanisms that do not extend to the muscle autoantigens so frequently targeted in thymoma patients but so rarely recognized in APS-1. Thus our findings argue strongly for a tolerogenic function of AIRE beyond its role in negative T-cell selection in human thymopoiesis, and/or for specific autoimmunization against muscle in thymomas.

Determination of the Absolute Configurations of Natural Products via Density Functional Theory Calculations of Vibrational Circular Dichroism, Electronic Circular Dichroism, and Optical Rotation: The Iridoids Plumericin and Isoplumericin

The absolute configurations (ACs) of the iridoid natural products, plumericin (1) and isoplumericin (2), have been re-investigated using vibrational circular dichroism (VCD) spectroscopy, electronic circular dichroism (ECD) spectroscopy, and optical rotatory dispersion (ORD). Comparison of DFT calculations of the VCD spectra of 1 and 2 to the experimental VCD spectra of the natural products, (+)-1 and (+)-2, leads unambiguously to the AC (1R,5S,8S,9S,10S)-(+) for both 1 and 2. In contrast, comparison of time-dependent DFT (TDDFT) calculations of the ECD spectra of 1 and 2 to the experimental spectra of (+)-1 and (+)-2 does not permit definitive assignment of their ACs. On the other hand, TDDFT calculations of the ORD of (1R,5S,8S,9S,10S)-1 and -2 over the range of 365-589 nm are in excellent agreement with the experimental data of (+)-1 and (+)-2, confirming the ACs derived from the VCD spectra. Thus, the ACs initially proposed by Albers-Schönberg and Schmid are shown to be correct, and the opposite ACs recently derived from the ECD spectra of 1 and 2 by Elsässer et al. are shown to be incorrect. As a result, the ACs of other iridoid natural products obtained by chemical correlation with 1 and 2 are not in need of revision.

Deoxyribonucleic acid damage and spontaneous mutagenesis in the thyroid gland of rats and mice

Thyroid tumors are a frequent finding not only in iodine-deficient regions. They are predominantly characterized by somatic genetic changes (e.g. point mutations or rearrangements). Because slow thyroid proliferation is a apparent contradiction to a high frequency of tumor initiation, we characterized mutational events in thyroid. First we studied the frequency of certain base exchanges in somatic TSH receptor (TSHR) mutations and determined the spontaneous mutation rate in thyroid and liver. Then we applied different protocols of the comet assay to quantify genomic DNA damage and conducted immunohistochemistry for 8-oxoguanine as a molecular marker for oxidative stress. Among 184 somatic mutations of the human TSHR found in thyroid tumors, C-->T transitions had a unexpectedly high frequency (>32%). The mutation rate in thyroid is 8-10 times higher than in other organs. The comet assay detected increased levels of oxidized pyrimidine (2- to 3-fold) and purine (2- to 4-fold) in thyroid, compared with liver and lung, and a 1.6-fold increase of oxidized purine, compared with spleen. Immunohistochemistry revealed high levels of 8-oxoguanine in thyroid epithelial cells. We have shown a strikingly high mutation rate in the thyroid. Furthermore, results of the comet assay as well as immunohistochemistry suggest that oxidative DNA modifications are a likely cause of the higher mutation rate. It is possible that free radicals resulting from reactive oxygen species in the thyroid generate mutations more frequently. This is also supported by the spectrum of somatic mutations in the TSHR because more frequent base changes could stem from oxidized base adducts that we detected in the comet assay and with immunohistochemistry.

Regulation of ghrelin is related to estimated insulin sensitivity in obese children

OBJECTIVE

To investigate whether ghrelin concentrations and their changes during weight loss in obese children are associated with parameters of glucose and insulin metabolism.

DESIGN

Total plasma ghrelin, insulin and glucose were measured during oral glucose tolerance testing before and after diet-induced weight loss over 6 weeks.

SETTING

In-patient rehabilitation program in a pediatric hospital.

PARTICIPANTS

Twenty-three obese children (age 10-16 years) and 11 normal weight controls (age 10-15 years).

OUTCOME MEASURES

Changes in ghrelin concentrations during weight loss and correlation analysis of changes in ghrelin and changes in parameters of glucose and insulin metabolism. After data collection, subgroup analysis of obese patients with high, medium and low estimated insulin sensitivity whole-body insulin sensitivity index (WBISI) was performed.

RESULTS

Weight loss increased the area under the curve (AUC) of ghrelin by 26% (P<0.001). The increase in ghrelin AUC correlated significantly with improved estimated insulin sensitivity (WBISI) (r=0.69, P<0.001). The independent predicting effect of WBISI was confirmed in multivariate analysis. In children with low WBISI, ghrelin reached the level of control values after weight loss. In children with high WBISI, ghrelin increased markedly above control levels.

CONCLUSIONS

Changes in ghrelin are independently associated with changes in glucose and insulin metabolism. The increase in plasma ghrelin above control levels was limited to obese children with high WBISI.