bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of high levels of glucose on the steroidogenesis and the expression of adiponectin receptors in rat ovarian cells
Authors: Chabrolle Christine , JeanPierre Eric , Tosca Lucie , Ramé Christelle , Dupont Joëlle 
Published: March 2008

AbstractBackgroundReproductive dysfunction in the diabetic female rat is associated with altered folliculogenesis and steroidogenesis. However, the molecular mechanisms involved in the reduction of steroid production have not been described. Adiponectin is an adipocytokine that has insulin-sensitizing actions including stimulation of glucose uptake in muscle and suppression of glucose production in liver. Adiponectin acts via two receptor isoforms – AdipoR1 and AdipoR2 – that are regulated by hyperglycaemia and hyperinsulinaemia in liver and muscle. We have recently identified AdipoR1 and AdipoR2 in rat ovary. However, their regulation in ovaries of diabetic female rat remains to be elucidated.MethodsWe incubated rat primary granulosa cells in vitro with high concentrations of glucose (5 or 10 g/l) + or - FSH (10-8 M) or IGF-1 (10-8 M), and we studied the ovaries of streptozotocin-induced diabetic rats (STZ) in vivo. The levels of oestradiol and progesterone in culture medium and serum were measured by RIA. We used immunoblotting to assay key steroidogenesis factors (3beta HSD, p450scc, p450 aromatase, StAR), and adiponectin receptors and various elements of signalling pathways (MAPK ERK1/2 and AMPK) in vivo and in vitro. We also determined cell proliferation by [3H] thymidine incorporation.ResultsGlucose (5 or 10 g/l) impaired the in vitro production in rat granulosa cells of both progesterone and oestradiol in the basal state and in response to FSH and IGF-1 without affecting cell proliferation and viability. This was associated with substantial reductions in the amounts of 3beta HSD, p450scc, p450 aromatase and StAR proteins and MAPK ERK1/2 phosphorylation. In contrast, glucose did not affect the abundance of AdipoR1 or AdipoR2 proteins. In vivo, as expected, STZ treatment of rats caused hyperglycaemia and insulin, adiponectin and resistin deficiencies. Plasma progesterone and oestradiol levels were also reduced in STZ rats. However, the amounts of 3beta HSD and p450 aromatase were the same in STZ rat ovary and controls, and the amounts of StAR and p450scc were higher. Streptozotocin treatment did not affect adiponectin receptors in rat ovary but it increased AMPK phosphorylation without affecting MAPK ERK1/2 phosphorylation.ConclusionHigh levels of glucose decrease progesterone and oestradiol production in primary rat granulosa cells and in STZ-treated rats. However, the mechanism that leads to reduced ovarian steroid production seems to be different. Furthermore, adiponectin receptors in ovarian cells are not regulated by glucose.
Total body water estimations in healthy men and women using bioimpedance spectroscopy: a deuterium oxide comparison
Authors: Moon Jordan R , Tobkin Sarah E , Roberts Michael D , Dalbo Vincent J , Kerksick Chad M , Bemben Michael G , Cramer Joel T , Stout Jeffrey R 
Published: March 2008

Abstract

Background
Total body water (TBW) estimations have been used to estimate body composition, particularly fat-free mass, to aid in nutritional interventions, and to monitor hydration status. In the past, bioimpedance spectroscopy (BIS) devices have been used to estimate TBW. Previous investigations have examined the validity of the XiTRON 4000B (XiTRON Technologies) BIS device for estimating TBW. Recently, a new BIS device (Imp™ SFB7) has become available, claiming greater precision when estimating TBW. The Imp™ SFB7 (SFB7) is based on similar BIS principles, while offering increased portability and a greater range of frequencies when compared to older devices, such as the XiTRON 4000B (4000B). The purpose of this study was to examine the validity of the SFB7 for estimating total body water in healthy college-age men and women compared to the 4000B and deuterium oxide (D2O).

Methods
Twenty-eight Caucasian men and women (14 men, 14 women; 24 ± 4 yrs; 174.6 ± 8.7 cm; 72.80 ± 17.58 kg) had their TBW estimated by the SFB7, the 4000B, and D2O.

Results
Both BIS devices produced similar standard error of estimate (SEE) and r values (SFB7, SEE = 2.12L, r = 0.98; 4000B, SEE = 2.99L, r = 0.96) when compared to D2O, though a significant constant error (CE) was detected for the 4000B (2.26L, p ≤ 0.025). The 4000B produced a larger total error (TE) and CE (TE = 3.81L, CE = 2.26L) when compared to the SFB7 (TE = 2.21L, CE = -0.09L). Additionally, the limits of agreement were larger for the 4000B (-3.88 to 8.39L) than the SFB7 (-4.50 to 4.31L). These results were consistent when sex was analyzed separately, though women produced lower SEE and TE values for both devices.

Conclusion
The 4000B and SFB7 are valid BIS devices when compared to D2O to estimate TBW in college-age Caucasian men and women. Furthermore, the new SFB7 device displayed greater precision in comparison to the 4000B, which may decrease the error when estimating TBW on an individual basis.
Successful Long-Term Growth Hormone Therapy in a Girl with Haploinsufficiency of the Insulin-Like Growth Factor-I Receptor due to a Terminal 15q26.2-&gt;qter Deletion Detected by Multiplex Ligation Probe Amplification
Authors: Walenkamp Marie J. E. , de Muinck Keizer-Schrama Sabine M. P. F. , de Mos Marianne , Kalf Margot E. , van Duyvenvoorde Hermine A. , Boot Annemieke M. , Kant Sarina G. , White Stefan J. , Losekoot Monique , Den Dunnen Johan T. , Karperien Marcel , Wit Jan M. 
Published: March 2008

Abstract
Context: Microscopically visible heterozygous terminal 15q deletions encompassing the IGF1R gene are rare and usually associated with intrauterine growth retardation and short stature. The incidence of submicroscopic deletions is unknown, as is the effect of GH therapy in this condition.
Objective: The objective of the study was to describe the use of a novel genetic technique [multiplex ligation probe amplification (MLPA)] to detect haploinsufficiency of the IGF1R gene in a patient suspected of an IGF1R gene defect and evaluate the effect of long-term GH therapy.
Patient: A 15-yr-old adolescent, born small for gestational age, showed persistent postnatal growth retardation, microcephaly, and elevated IGF-I levels. She had been treated with GH since the age of 5 yr.
Methods: MLPA and array comparative genomic hybridization (aCGH) were performed to examine gene copy number changes. Dermal fibroblast cultures were used for functional analysis.
Results: With MLPA, a deletion of one copy of the IGF1R gene was detected, defined by aCGH as a loss of 15q26.2-&gt;qter. IGF1R mRNA expression was decreased in fibroblasts. IGF-I binding and type 1 IGF receptor protein expression as well as activation of type 1 IGF receptor autophosphorylation and protein kinase B/Akt by IGF-I tended to be lower, but this did not reach statistical significance. GH treatment resulted in a good growth response and a normal adult height.
Conclusions: MLPA and aCGH are useful tools to detect submicroscopic deletions of the IGF1R gene in patients born small for gestational age with persistent growth failure. The phenotype resembles that of a heterozygous inactivating IGF1R mutation. Long-term GH therapy causes growth acceleration in childhood and a normal adult height.
Rab18 Is Reduced in Pituitary Tumors Causing Acromegaly and Its Overexpression Reverts Growth Hormone Hypersecretion
Authors: Vazquez-Martinez Rafael , Martinez-Fuentes Antonio J. , Pulido Marina R. , Jimenez-Reina Luis , Quintero Ana , Leal-Cerro Alfonso , Soto Alfonso , Webb Susan M. , Sucunza Nuria , Bartumeus Frederic , Benito-Lopez Pedro , Galvez-Moreno Maria A. , Castaño Justo P. , Malagon Maria M. 
Published: March 2008

Abstract
Context: Rab proteins regulate the sequential steps of intracellular membrane transport. Alterations of these GTPases and their associated proteins are emerging as the underlying cause for several human diseases involving dysregulated secretory activities.
Objective: Herein we investigated the role of Rab18, which negatively regulates hormone secretion by interacting with secretory granules, in relation to the altered functioning of tumoral pituitary somatotropes causing acromegaly.
Patients: A total of 18 patients diagnosed with pituitary tumors causing acromegaly (nine patients) or nonfunctioning adenomas (nine patients) underwent endoscopic transsphenoidal surgery. Adenomas were subsequently processed to evaluate Rab18 production in relation to GH secretion.
Results: We found that somatotropinoma cells are characterized by a high secretory activity concomitantly with a remarkably reduced Rab18 expression (15%) and protein content levels (30%), as compared with cells from nonfunctioning pituitary adenomas derived from patients with normal or reduced GH plasma levels (100%). Furthermore, immunoelectron microscopy revealed that Rab18 association with the surface of GH-containing secretory granules was significantly lower in somatotropes from acromegalies than nonfunctioning pituitary adenomas. Finally, we provide evidence that modulation of Rab18 gene expression can revert substantially the hypersecretory activity of cells because Rab18 overexpression reduced by 40% the capacity of cells from acromegalies to respond to GHRH stimulation.
Conclusion: These results suggest that molecular alterations affecting individual components of the secretory granule traffic machinery can contribute to maintain a high level of GH in plasma. Accordingly, Rab18 constitutes a valuable target as a diagnostic, prognostic, and/or therapeutic tool for human acromegaly.
Reduced Abdominal Adiposity and Improved Glucose Tolerance in Growth Hormone-Treated Girls with Turner Syndrome
Authors: Wooten Nicole , Bakalov Vladimir K. , Hill Suvimol , Bondy Carolyn A. 
Published: March 2008

Abstract
Background: Individuals with Turner syndrome (TS) are at increased risk for impaired glucose tolerance and diabetes mellitus. It is unknown whether pharmacological GH treatment commonly used to treat short stature in TS alters this risk.
Objective: Our objective was to compare adiposity and glucose tolerance in GH-treated vs. untreated girls with TS.
Methods: In a cross sectional study, GH-treated girls with TS (n = 76; age 13.6 ± 3.7 yr) were compared to girls with TS that never received GH (n = 26; age 13.8 ± 3.5 yr). Protocol studies took place in the NIH Clinical Research Center from 2001–2006 and included oral glucose tolerance tests, body composition analysis by dual-energy x-ray absorptiometry, and abdominal fat quantification by magnetic resonance imaging. GH was not given during testing.
Results: Total body fat (35 ± 8 vs. 28 ± 8%, P &lt; 0.0001), sc abdominal fat (183 vs. 100 ml, P = 0.001), and intraabdominal fat (50 vs. 33 ml, P &lt; 0.0001) were significantly greater in untreated girls. Fasting glucose and insulin were similar, but the response to oral glucose was significantly impaired in the untreated group (28 vs. 7% with impaired glucose tolerance, P = 0.006). A specific excess of visceral fat and insulin resistance was apparent only in postpubertal girls that had never received GH. GH-treated girls demonstrated lower adiposity compared with untreated girls for an average of 2 yr after discontinuation of GH.
Conclusions: Abdominal adiposity is significantly lower and glucose tolerance significantly better in GH-treated vs. untreated girls with TS, suggesting that beneficial effects upon body composition and regional fat deposition outweigh transient insulin antagonism associated with GH administration.
Androgen Deprivation Therapy in Prostate Cancer and Metabolic Risk for Atherosclerosis
Authors: Shahani Sadeka , Braga-Basaria Milena , Basaria Shehzad 
Published: March 2008

Abstract
Context: Prostate cancer (PCa) is the most common cancer in men. Androgen-deprivation therapy (ADT) is generally employed in the treatment of locally advanced and metastatic PCa. Although its use as an adjuvant therapy has resulted in improved survival in some patients, ADT has negative consequences. Complications like osteoporosis, sexual dysfunction, gynecomastia, and adverse body composition are well known. Recently, metabolic complications like insulin resistance, diabetes, dyslipidemia, and metabolic syndrome have emerged, which may be responsible for the increased cardiovascular mortality in this population.
Evidence Acquisition: A MEDLINE search was conducted for articles published over the last 20 yr based on the key words androgen deprivation therapy AND insulin resistance, hyperglycemia, diabetes, dyslipidemia, metabolic syndrome, and cardiovascular disease. Relevant studies in non-PCa populations evaluating the association between testosterone and metabolism were also reviewed and briefly mentioned where relevant.
Evidence Synthesis: Prospective studies evaluating early (3–6 months) metabolic changes of ADT show development of hyperinsulinemia; however, glucose levels remain normal. Cross-sectional studies of men undergoing long-term (≥12 months) ADT reveal higher prevalence of diabetes and metabolic syndrome compared with controls. Furthermore, men undergoing ADT also experience higher cardiovascular mortality.
Conclusion: Long-term prospective studies of ADT are needed to determine the timing of onset of these metabolic complications and to investigate the mechanism behind them. In the meantime, we recommend baseline and serial screening for fasting glucose, lipids, and other cardiovascular risk factors in men receiving ADT. Glucose tolerance tests and cardiac evaluation may be required in selected cases.
Surface roughness prediction model for CNC machining of polypropylene
Authors: Dhokia V G , Kumar S , Vichare P , Newman S T , Allen R D 
Published: March 2008

Cutting strategy research has traditionally been focused on hard materials that are intrinsically difficult to machine. An increase in the desire for personalized products has led to the requirement of the direct machining of polymers for personalized products. Little research is evident in the literature on the analysis of optimal machining parameters for machining materials such as polypropylene. One of the vital factors that affects the quality of polypropylene products and the respective machining strategy is surface roughness. This research is aimed at extracting information on the machining of polypropylene materials. A surface roughness predictive model based on neural networks has been developed. The design of experiments approach is used to obtain an adequate predictive model for the process planning which is further utilized as an input to the predictive model. The model mainly hinges on three independent variables namely spindle speed, feed rate, and depth of cut. Extensive experimental work on different network topologies and training algorithms has been performed to predict the behaviour of the surface roughness for machined polypropylene products. The results illustrate the benefits of being able to determine surface roughness values. This allows for the determination of optimal cutting strategies and tooling for the required surface roughness. The performance predictive model has been found to be satisfactory over the dataset for polypropylene machining. Hypothesis testing has also been carried out to identify the confidence of the predictive model.
Tool wear aspects when applying high-speed tapping on grey cast iron
Authors: A A Bezerra , R T Coelho 
Published: March 2008

Tool wear is a very important subject affecting the economics of machining, especially in tapping, since it is one of the last operations to be performed within most operation sequences. In the present study, some aspects of tapping such as the mechanisms and types of wear were investigated in taps working at conventional and high-speed cutting (HSC). Additionally, different types of coatings and cooling/lubrication conditions were used. The tapping operation (M8 × 1.25) was performed in through holes with two cutting speeds (30 and 60 m/min) in grey cast iron GG25. Lubrication conditions tested were dry and with minimal quantity of lubricant. Tap materials were manufactured by powder metallurgy and coated with (TiAl)N and with TiCN. A go—non-go gauge criterion was used to assess tool life. The wear and surface aspects of the tools and workpiece were evaluated by scanning electron microscopy and energy dissipation spectroscopy. Torque signals were also measured during the tests. The main wear mechanism observed was adhesion, although some abrasion and diffusion may also have occurred, and the main type of wear was flank wear. The adhesion of workpiece material on the tool was the main and decisive factor ending tool life. Tool coatings proved to be an efficient way to minimize adhesion. Torque signals followed the same pattern as the flank wear and no significant change was observed when the cutting speed was increased.
Aerostat for electrical power generation —concept feasibility
Authors: Aglietti G S , Markvart T , Tatnall A R , Walker S J 
Published: March 2008

The current paper examines the feasibility of using a high altitude tethered aerostat as a platform for producing a substantial quantity of electric energy and transmitting it to Earth using the mooring cable. Based on realistic values for the relevant engineering parameters that describe the technical properties of the materials and subsystems, a static analysis of the aerostat in its deployed configuration has been carried out. The results of the computations, although of a preliminary nature, demonstrate that the concept is technically feasible. There are, nevertheless, issues to be addressed to improve the performance. However none of these issues is deemed to negate the technical feasibility of this concept. A test case is investigated in terms of preliminary sizing of the aerostat, including mooring cable and solar cell coverage, and it shows the capability to deliver power to the ground in excess of 95 kW. A brief assessment of the cost has also been carried out to investigate the potential gains offered by this system to produce solar electric energy.
Can compressive stress be measured experimentally within the annulus fibrosus of degenerated intervertebral discs?
Authors: Chu J Y , Skrzypiec D , Pollintine P , Adams M A 
Published: March 2008

The aims were to assess the ability of a pressure transducer to measure compressive stress within the annulus fibrosus of degenerated intervertebral discs. Measurements could help to explain the mechanisms of disc failure and low back pain. The methods used were as follows. Thirteen full-depth cores of annulus, 7 mm in diameter, were removed from the middle and outer annuli of two severely degenerated human discs and constrained within a metal cylinder. Then static compressive forces were applied by a planeended metal indenter of diameter 6.8 mm, while a strain-gauged pressure transducer, side mounted in a needle of diameter 0.9 mm and calibrated in saline, was pulled through the issue. The transducer output was converted into stress, and the average measured stress was compared with the nominal applied stress. Measurements were repeated at up to 21 load levels, with the transducer oriented vertically and horizontally. The results showed that the measured and applied stress were linearly related (average r2=0.98) with a mean gradient (calibration factor) of 0.98 (vertical stress) and 0.92 (horizontal stress). Gradients ranged between 1.28 and 0.73. Damaged transducers grossly under-recorded ‘stress’ even though their output remained proportional to applied load. It was concluded that pressure transducers can measure compressive stress inside a degenerated human annulus. The tissue is sufficiently deformable to allow efficient coupling of stress between the matrix and transducer membrane. Damage to the transducer can give misleading results.
Can extra-articular strains be used to measure facet contact forces in the lumbar spine? An in-vitro biomechanical study
Authors: Zhu Q A , Park Y B , Sjovold S G , Niosi C A , Wilson D C , Cripton P A , Oxland T R 
Published: March 2008

Experimental measurement of the load-bearing patterns of the facet joints in the lumbar spine remains a challenge, thereby limiting the assessment of facet joint function under various surgical conditions and the validation of computational models. The extra-articular strain (EAS) technique, a non-invasive measurement of the contact load, has been used for unilateral facet joints but does not incorporate strain coupling, i.e. ipsilateral EASs due to forces on the contralateral facet joint. The objectives of the present study were to establish a bilateral model for facet contact force measurement using the EAS technique and to determine its effectiveness in measuring these facet joint contact forces during three-dimensional flexibility tests in the lumbar spine. Specific goals were to assess the accuracy and repeatability of the technique and to assess the effect of soft-tissue artefacts. In the accuracy and repeatability tests, ten uniaxial strain gauges were bonded to the external surface of the inferior facets of L3 of ten fresh lumbar spine specimens. Two pressure-sensitive sensors (Tekscan) were inserted into the joints after the capsules were cut. Facet contact forces were measured with the EAS and Tekscan techniques for each specimen in flexion, extension, axial rotation, and lateral bending under a ±7.5 N m pure moment. Four of the ten specimens were tested five times in axial rotation and extension for repeatability. These same specimens were disarticulated and known forces were applied across the facet joint using a manual probe (direct accuracy) and a materials-testing system (disarticulated accuracy). In soft-tissue artefact tests, a separate set of six lumbar spine specimens was used to document the virtual facet joint contact forces during a flexibility test following removal of the superior facet processes. Linear strain coupling was observed in all specimens. The average peak facet joint contact forces during flexibility testing was greatest in axial rotation (71±25 N), followed by extension (27±35 N) and lateral bending (25±28 N), and they were most repeatable in axial rotation (coefficient of variation, 5 per cent). The EAS accuracy was about 20 per cent in the direct accuracy assessment and about 30 per cent in the disarticulated accuracy test. The latter was very similar to the Tekscan accuracy in the same test. Virtual facet loads (r.m.s.) were small in axial rotation (12 N) and lateral bending (20 N), but relatively large in flexion (34 N) and extension (35 N). The results suggested that the bilateral EAS model could be used to determine the facet joint contact forces in axial rotation but may result in considerable error in flexion, extension, and lateral bending.