Increased levels of the Akt-specific phosphatase PH domain leucine-rich repeat protein phosphatase (PHLPP)-1 in obese participants are associated with insulin resistance

AIMS/HYPOTHESIS

We determined the contribution to insulin resistance of the PH domain leucine-rich repeat protein phosphatase (PHLPP), which dephosphorylates Akt at Ser473, inhibiting its activity. We measured the abundance of PHLPP in fat and skeletal muscle from obese participants. To study the effect of PHLPP on insulin signalling, PHLPP (also known as PHLPP1) was overexpressed in HepG2 and L6 cells.

METHODS

Subcutaneous fat samples were obtained from 82 morbidly obese and ten non-obese participants. Skeletal muscle samples were obtained from 12 obese and eight non-obese participants. Quantification of PHLPP-1 in human tissues was performed by immunoblotting. The functional consequences of recombinant PHLPP1 overexpression in hepatoma HepG2 cells and L6 myoblasts were investigated.

RESULTS

Of the 82 obese participants, 31 had normal fasting glucose, 33 impaired fasting glucose and 18 type 2 diabetes. PHLPP-1 abundance was twofold higher in the three obese groups than in non-obese participants (p = 0.004). No differences were observed between obese participants with normal fasting glucose, impaired fasting glucose or type 2 diabetes. PHLPP-1 abundance was correlated with basal Akt Ser473 phosphorylation (r = -0.48; p = 0.001), BMI (r = 0.44; p < 0.0001), insulin (r = 0.35; p < 0.0001) and HOMA (r = 0.38; p < 0.0001). PHLPP-1 abundance was twofold higher in the skeletal muscle of 12 obese participants than in that of eight non-obese participants (p < 0.0001). Insulin treatment of HepG2 cells resulted in a dose- and time-dependent upregulation of PHLPP-1. Overexpression of PHLPP1 in HepG2 cells and L6 myoblasts resulted in impaired insulin signalling involving Akt/glycogen synthase kinase 3, glycogen synthesis and glucose transport.

CONCLUSIONS/INTERPRETATION

Increased abundance of PHLPP-1, production of which is regulated by insulin, may represent a new molecular defect in insulin-resistant states such as obesity.

Numb activates the E3 ligase Itch to control Gli1 function through a novel degradation signal

Hedgehog pathway regulates tissue patterning and cell proliferation. Gli1 transcription factor is the major effector of Hedgehog signaling and its deregulation is often associated to medulloblastoma formation. Proteolytic processes represent a critical mechanism by which this pathway is turned off. Here, we characterize the regulation of an ubiquitin-mediated mechanism of Gli1 degradation, promoted by the coordinated action of the E3 ligase Itch and the adaptor protein Numb. We show that Numb activates the catalytic activity of Itch, releasing it from an inhibitory intramolecular interaction between its homologous to E6-AP C-terminus and WW domains. The consequent activation of Itch, together with the recruitment of Gli1 through direct binding with Numb, allows Gli1 to enter into the complex, resulting in Gli1 ubiquitination and degradation. This process is mediated by a novel Itch-dependent degron, composed of a combination of two PPXYs and a phospho-serine/proline motifs, localized in Gli1 C-terminal region, indicating the role of two different WW docking sites in Gli1 ubiquitination. Remarkably, Gli1 protein mutated in these modules is no longer regulated by Itch and Numb, and determines enhanced Gli1-dependent medulloblastoma growth, migration and invasion abilities, as well as in vitro transforming activity. Our data reveal a novel mechanism of regulation of Gli1 stability and function, which influences Hedgehog/Gli1 oncogenic potential.

Bandwidth tuning triggers interplay of charge order and superconductivity in two-dimensional organic materials

We observe charge-order fluctuations in the quasi-two-dimensional organic superconductor β''-(BEDT-TTF)2SF5CH2CF2SO3, both by means of vibrational spectroscopy, locally probing the fluctuating charge order, and by investigating the in-plane dynamical response by infrared reflectance spectroscopy. The decrease of the effective electronic interaction in an isostructural metal suppresses both charge-order fluctuations and superconductivity, pointing to their interplay. We compare the results of our experiments with calculations on the extended Hubbard model.

Autologous serum skin test reactivity and basophil histamine release test in patients with nasal polyposis: preliminary results

An eosinophilic inflammatory process is generally observed in patients suffering from nasal polyposis (NP), however its onset has not yet been defined. It has been suggested that immune activation of inflammatory cells may be the cause. The aim of this study is to verify whether autoantibodies and/or histamine-releasing factors are present in the serum of patients suffering from NP. In fact, we assume that autoantibodies and/or histamine-releasing factors, as already demonstrated in chronic idiopathic urticaria and asthma, may be involved in the pathogenesis of NP. In this case-control analytical study 40 patients with NP and 27 control subjects underwent the in vivo autologous serum skin test (ASST). The sera from 6 patients suffering from NP and 9 control group subjects, who had all been previously studied and randomly selected, underwent basophil histamine release assay from normal donor as a pilot study. The ASST showed positive results in 55% of patients suffering from NP versus 8% of the control group (p= .00006), the basophil histamine release test (BHRT) turned out positive in all patients tested and in 11% of the control group. We found a weak positive correlation between the percentage of histamine release and the wheal diameter. ASST reactivity is very frequent in patients suffering from NP, thus suggesting the presence of histamine-releasing factors in the blood stream. The BHRT was positive in the serum of all patients, thus suggesting the presence of anti-FcepsilonRI, anti-IgE autoantibodies and/or other histamine-releasing factors, the presence of which can play a role in triggering and maintaining the eosinophilic inflammatory process in NP.

Reinke's edema: investigations on the role of MIB-1 and hepatocyte growth factor

Reinke's edema is a benign disease of the human vocal fold, which mainly affects the sub-epithelial layer of the vocal fold. Microscopic observations show a strongly oedematous epithelium with loosened intercellular junctions, a disruption of the extracellular connections between mucosal epithelium and connective tissue, closely adherent to the thyroarytenoid muscle. Thickening of the basal layer of epithelium, known as Reinke's space, high deposition of fibronectin and chronic inflammatory infiltration it is also visible. We analyzed, together with the hepatocyte growth factor (HGF), the expression level of MIB-1 in samples harvested from patients affected by Reinke's edema, in order to define its biological role and consider it as a possible prognostic factor in the follow-up after surgical treatment. We observed a moderate expression of HGF in the lamina propria of the human vocal fold and in the basal membrane of the mucosal epithelium. Our finding suggests that this growth factor acts as an anti - fibrotic agent in Reinke's space and affects the fibronectin deposition in the lamina propria. MIB-1, on the contrary, showed a weak expression in the basement membrane of the mucosal epithelium and a total absence in the lamina propria deep layer, thus suggesting that only the superficial layer is actively involved in the reparatory process with a high regenerative capacity, together with a high deposition of fibronectin. The latter is necessary for the cellular connections reconstruction, after the inflammatory infiltration.

Circadian rhythmicity of lymphocyte subpopulations and relationship with neuro-endocrine system

Lymphocyte subpopulations present circadian variation of some of their subsets, this variation may influence magnitude and expression of the immune responses and may be related to the variation of neuro-endocrine humoral factors. In our study cortisol, melatonin, TRH, TSH, FT4, GH, IGF1 and IL2 serum levels were measured and lymphocyte subpopulation analyses were performed on blood samples collected every four hours for 24 hours from 11 healthy male subjects aged 38-55 years. A clear circadian rhythm was validated for cortisol serum levels, CD8, CD16, TcRδ1 with acrophase in the morning and at noon, and for melatonin, TRH, TSH, GH, CD3, CD4, CD4/CD8 ratio, HLA-DR, CD20 and CD25 with acrophase at night. Changes of serum levels of FT4, IGF1 and IL2 did not show circadian rhythmicity. In the photoperiod (06.00-18.00h) and in the scotoperiod (18.00-06.00h) there were significant correlations among the lymphocyte subpopulations and humoral factors studied. The results show that specific lymphocyte subsets present different profiles of nyctohemeral changes and different timed relationships with neuro-endocrine hormones.

Rearrangements of NTRK1 gene in papillary thyroid carcinoma

TRK oncogenes are observed in a consistent fraction of papillary thyroid carcinoma (PTC); they arise from the fusion of the 3' terminal sequences of the NTRK1/NGF receptor gene with 5' terminal sequences of various activating genes, such as TPM3, TPR and TFG. TRK oncoproteins display constitutive tyrosine-kinase activity, leading to in vitro and in vivo transformation. In this review studies performed during the last 20 years will be summarized. The following topics will be illustrated: (a) frequency of TRK oncogenes and correlation with radiation and tumor histopathological features; (b) molecular mechanisms underlying NTRK1 oncogenic rearrangements; (c) molecular and biochemical characterization of TRK oncoproteins, and their mechanism of action; (d) role of activating sequences in the activation of TRK oncoproteins.

Circadian variations of cortisol, melatonin and lymphocyte subpopulations in geriatric age

A number of age-related changes in the 24-hour hormonal and non-hormonal rhythms have been found in older human beings. Lymphocyte subpopulations present circadian variation of some of their subsets and this variation may influence magnitude and expression of the immune responses. Numerous interactions exist among the nervous, endocrine and immune systems, mediated by neurotransmitters, hormones and cytokines. The aim of this study is to evaluate circadian variations of some endocrine and immune factors in older adults. Cortisol and melatonin serum levels were measured and lymphocyte subpopulation analyses were performed on blood samples collected every four hours for 24 hours from ten healthy young and middle-aged subjects and from ten healthy elderly subjects. There was a statistically significant difference between the groups in the observed values of CD20 (higher in young and middle-aged subjects) and CD25 and DR+ T cells (higher in elderly subjects). In the group of young and middle-aged subjects a clear circadian rhythm was validated for the time-qualified changes of all the factors studied. In the group of elderly subjects a number of rhythms were absent or altered. The results of the current study show that aging is associated with enhanced responsiveness of T cell compartment and alterations of circadian rhythmicity.

[Phlegmons of the neck: our experience with 7 cases]

Phlegmons of the neck originate from infectious diseases of head and neck. Odontogeneous inflammation of the oral cavity is most frquently primary lesion, followed by sinusitis, otitis, as well as radiation therapy and surgical procedures. Phlegmons of head and neck can drain into the spaces among the muscles, aponevrosis, organs inside the neck like sublingual space, lateral pharyngeal space, retro-pharyngeal space or pre-vertebral space. We hereby report our experience with 7 patients treated from 2001 to 2005.

Lipoma of the larynx: a case report

Lipoma is a benign tumour of mesenchymal origin with a very rare occurrence in the upper aero-digestive tract. To date, approximately 100 cases have been described in the literature. This lesion has a slow growth and, therefore, can present with various symptoms due to the mass effect with obstruction and compression on neighbouring structures, including dysphagia for liquid and solid food, dyspnoea and hoarseness. For a precise pre-operative diagnosis, indirect or direct laryngoscopy (flexible fibre-optic laryngoscopy) can be employed or, if necessary, also imaging techniques such as computed tomography scan and magnetic resonance imaging scan. These offer more useful information for better treatment planning. Surgery is the treatment of choice and includes endoscopic techniques and an external surgical approach (cervicotomy). It is very important to completely remove these benign neoplasms in order to avoid local recurrence. The present report referring to a case of laryngeal lipoma removed through an external surgical approach, aims to demonstrate that the choice of an external surgical approach is required for complete surgical removal of a large lipoma in order to prevent any possible recurrence. Furthermore, it is useful to keep in mind the possibility of recurrence of lipomas after long free intervals; therefore, it is mandatory to observe these patients at long-term follow-up.

Echocardiography and dual-energy x-ray absorptiometry in the elderly patients with metabolic syndrome: a comparison of two different tecniques to evaluate visceral fat distribution

OBJECTIVES

Metabolic syndrome (MetS) is an important risk factor for vascular diseases. Two simple and low cost measurements, the epicardial fat (EFT) obtained by echocardiography and abdominal fat (AFT) thickness evaluated by Dual-Energy X-Ray Absorptiometry (DEXA), have been validated as a markers of fat storage in young adults and elderly patients affected by MetS. At present no studies are available yet to compare the two techniques and to test their relationship with MetS. Moreover, no data exit concerning the association between hepatic steatosis, a well known indicator of intra hepatic fat storage and perivisceral fat storage. Aims of our study were: 1) to compare EFT and AFT in a group of patients with and without MetS; 2) to study whether and how these two different approaches predict MetS or risk of malnutrition in the obese elderly; 3) to evaluate the relationship between MetS occurrence, EFT, AFT and hepatic steatosis (HS).

SETTING AND PARTICIPANTS

We studied 55 elderly outpatients ( 29 males and 26 females) referred to MetS service of the IRCCS "Casa Sollievo della Sofferenza" during the year 2007.

MEASUREMENTS

Subjects underwent a complete clinical and anthropometric evaluation, laboratory tests for glycaemia and lipid profile for MetS definition. Liver ultrasound was executed to verify the occurrence of HS, a well known indicator of intraparenchymal fat storage. HS was defined as hyperechoic liver pattern in patients without liver disease or hepatic enzymes abnormalities. MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. Echocardiography for EFT evaluation and DEXA for AFT and fat free mass of the abdomen (FFM) measurement were also performed. Mini Nutritional Assessment (MNA) was used to test the risk of malnutrition in the elderly.

RESULTS

Patients were divided in two groups according to the absence (24 patients Group 1) or the presence (31 patients Group 2) of the MetS. HS was present in 26 (57.7%) patients. MetS patients had significantly higher AFT and EFT, and lower FFM than patients without MetS. MNA scores were not different. EFT and AFT showed a good correlation ( R 0.8 p < 0.001) but only EFT was associated with the MetS. HS was also correlated to EFT and AFT. MNA showed a risk of malnutrition in 73% of MetS patients and 23% in patients without MetS but both EFT and AFT were not correlated with MNA scores.

CONCLUSIONS

In the elderly patient with MetS, AFT and EFT are greater than in non MetS patients. Both AFT and EFT are strongly correlated to HS but only EFT was associated with MetS. In obese patients, the risk of malnutrition, as evaluated by MNA, is not associated with an increased fat tissue measured by echocardiography or DEXA.

Molecular pathology of differentiated thyroid cancer

Thyroid cancer is the most common endocrine malignancy; it accounts for approximately 1% of all new case of cancer each year, and its incidence has increased significantly over the last few decades. The majority of thyroid tumors originate from follicular epithelial cells. Among them, papillary (PTC) and follicular carcinomas (FTC) represent the most common forms of differentiated thyroid cancer and account for approximately 80% and 15% of all cases, respectively. Specific genetic lesions are associated to each thyroid tumor histotype: BRAF mutations and RET/PTC and TRK oncogenes have been detected in PTC, whereas FTC is characterized by PAX8/PPARgamma rearrangements and RAS mutations. In this review we summarize studies on the molecular biology of the differentiated thyroid tumors, with particular interest in the associated genetic lesions and their role in thyroid carcinogenesis. We also report recent findings on gene expression and miRNA profiles of PTC and FTC.

Waiting-time distributions of magnetic discontinuities: clustering or Poisson process?

Using solar wind data from the Advanced Composition Explorer spacecraft, with the support of Hall magnetohydrodynamic simulations, the waiting-time distributions of magnetic discontinuities have been analyzed. A possible phenomenon of clusterization of these discontinuities is studied in detail. We perform a local Poisson's analysis in order to establish if these intermittent events are randomly distributed or not. Possible implications about the nature of solar wind discontinuities are discussed.

Redifferentiating agents in non-radioiodine avid cancer

Thyroid cancer is the most common malignant cancer of the endocrine system. Treatment for well differentiated forms include surgery and radioactive iodine ablation. When cancer cells exhibit a less differentiated phenotype they may no longer be able to accumulate iodine, making 131-I administration ineffective. Recent studies have demonstrated the important role of therapeutic agents that have redifferentiating potential, leading to reactivation and expression of thyrocyte-specific genes, including those responsible for iodine uptake. This review will discuss the results of the most recent studies on drugs with redifferentiating properties and their application in patients with radioiodine refractory thyroid cancer.

Universal newborn hearing screening programs in Italy: survey of year 2006

CONCLUSION

Our results suggest a rapid diffusion of newborn hearing screening programs in Italy and indicate that three conditions seem to play a crucial role in the implementation of Universal Newborn Hearing Screening (UNHS) programs: the size (>800 births/year) and location (metropolitan urban areas) of the hospital, and the presence of an audiologist in the UNHS coordinating team.

OBJECTIVES

The aim of this paper is to provide data on the degree of implementation and coverage of UNHS programs in Italy.

MATERIALS AND METHODS

Data were collected through a Screening Survey Questionnaire that was sent to all birthing hospitals active in Italy in 2006 and was filled in by the chief of the hospital or by the UNHS program coordinator.

RESULTS

In Italy UNHS coverage had undergone a steep increase from 29.3% in 2003 (156,048 newborns screened) to 48.4% in 2006 (262,103 screened). The majority of UNHS programs were implemented in the two most economically developed areas, i.e. in the north-west area (79.5%, 108,200 of 136,109 births), and in the north-east area (57.2%, 52,727 of 92,133 births), while a limited diffusion still remains in some areas, typically in the islands (11.3%, 7158 of 63,460 births).

Frailty syndrome is associated with altered circulating redox balance and increased markers of oxidative stress

Frailty syndrome (FS) is a condition described in aging and characterized by physical vulnerability to stress and lack of physiological reserve. In this study we aim to define whether circulating oxidative stress correlates to frailty in terms of glutathione balance and oxidative protein damage. In 62 elderly outpatients, classified as frail patients according to Fried's criteria, evaluation of reduced glutathione (GSH), oxidized glutathione (GSSG), tumor necrosis factor-alpha, malonaldehyde-(MDA) and 4-hydroxy-2,3-nonenal-(HNE) protein plasma adducts were performed. A significant increase in the GSSG was observed in patients with FS when compared to non-frail. No difference was shown in the GSH amount, suggesting a glutathione oxidation more than impairment of the synthesis. TNF-alpha, MDA- and HNE-adducts, were significantly higher in FS as compared to non-frail patients. A logistic regression model correlating FS with redox balance showed a close relationship between glutathione ratio (OR=1.8, 95% CI=1.2-2.5) and MDA adducts (OR=2.8, 95% CI=1.6-4.7) to frailty. Our findings show an association between oxidative imbalance and Frailty Syndrome. GSSG/GSH ratio and plasma protein adducts strongly predict the frailty conditions and seem to be reliable and easily measurable markers in the context of the multidimensional analysis of elderly patients.

An open-label, multicenter, phase I/II study of AT-101 in combination with docetaxel (D) and prednisone (P) in men with castrate-resistant prostate cancer (CRPC)

5062

Background: Antiapoptotic Bcl-2 family proteins are overexpressed in CRPC and contribute to resistance to therapy. The oral pan-Bcl-2 inhibitor AT-101 (Bcl-2, Bcl-XL, Bcl-W, Mcl-1) is active as a single agent and in combination in in vitro and in vivo tumor models and as a single agent in CRPC. The Phase 1 portion of the study determined the recommended dose for phase II to be D (75mg/m2 q3weeks) in combination with P (5mg b.i.d. on days 1–21), and AT-101 at 40mg b.i.d. on days 1–3 of each 21-day cycle, and was previously reported. Methods: Men ≥18 years of age with chemotherapy-naïve CRPC (N = 36). Safety (NCI CTCAE v3.0) and efficacy (Bubley Criteria for PSA) were assessed at 3-wk intervals. Radiological assessments were performed at 6-wk intervals for pts with soft tissue disease and bone scans were performed after cycle 6 and at the completion of therapy. Results: 36 patients (pts) have been enrolled in the study. Twenty-four (67%) pts achieved a partial response (PR) (>50% PSA decline), and 26 (72%) pts treated had at least a 30% decrease in PSA level. Nine of 19 pts (47%) with measurable disease had a PR. One PR was unconfirmed per RECIST. Thirteen pts (36%) completed >10 cycles of therapy (range 2–24) thus far. Four pts remains active. Safety data is available for 31 pts. The most common (>20%) Adverse Events (AEs) include: fatigue (68%), nausea (52%), diarrhea (45%), alopecia (32%), constipation and dysgeusia (26%), and neutropenia and vomiting (26%). Neutropenia was the only gr. 4 event occurring in more than one pt (3pts). Serious Adverse Events (SAEs) considered related were reported in 5 pts (16%). The only SAEs reported in 2 or more pts were urinary tract infection (3 pts) and deep vein thrombosis (2 pts) and none were considered related. No ileus has been reported. Conclusions: AT-101 when given in combination with D/P is well tolerated and shows preliminary evidence of efficacy in pts with CRPC. A randomized trial is ongoing.

[Table: see text]