bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection of Functional 5′
cis
-Acting Elements Promoting Efficient Sindbis Virus Genome Replication
Authors: Gorchakov Rodion , Hardy Richard , Rice Charles M. , Frolov Ilya 
Published: December 2003

ABSTRACT
The 5′ portion of the Sindbis virus (SIN) genome RNA is multifunctional. Besides initiating translation of the nonstructural polyprotein, RNA elements in the 5′ 200 bases of the SIN genome RNA, or its complement at the 3′ end of the negative-strand intermediate, play key roles in the synthesis of both negative- and positive-strand RNAs. We used here a combination of genetic and biochemical approaches to further dissect the functions of this sequence. Replacement of the SIN 5′ end in defective-interfering (DI) and genome RNAs with sequences from a distantly related alphavirus, Semliki Forest virus (SFV), resulted in nonviable chimeras. The addition of five nucleotides from the 5′ terminus of SIN restored negative-strand RNA synthesis in DI genomes but not their replication in vivo. Pseudorevertants of various SFV-SIN chimeras were isolated, and suppressor mutations were mapped to AU-rich sequences added to the 5′ end of the original SFV 5′ sequence or its “deleted” versions. Early pseudorevertants had heterogeneous 5′ termini that were inefficient for replication relative to the parental SIN 5′ sequence. In contrast, passaging of these pseudorevertant viral populations in BHK cells under competitive conditions yielded evolved, more homogeneous 5′-terminal sequences that were highly efficient for negative-strand synthesis and replication. These 5′-terminal sequences always began with 5′-AU, followed by one or more AU repeats or short stretches of oligo(A). Further analysis demonstrated a positive correlation between the number of repeat units and replication efficiency. Interestingly, some 5′ modifications restored high-level viral replication in BHK-21 cells, but these viruses were impaired for replication in the cells of mosquito origin. These studies provide new information on sequence determinants required for SIN RNA replication and suggest new strategies for restricting cell tropism and optimizing the packaging of alphavirus vectors.
Long-Term Transgene Expression in Proliferating Cells Mediated by Episomally Maintained High-Capacity Adenovirus Vectors
Authors: Kreppel Florian , Kochanek Stefan 
Published: December 2003

ABSTRACT

High-capacity “gutless” adenovirus vectors (HC-AdV) mediate long-term transgene expression in resting cells in vitro and in vivo because of low toxicity and immunogenicity. However, in proliferating cells, expression is transient since HC-AdV genomes do not possess elements that allow for replication and segregation of the replicated genomes to daughter cells. We developed a binary HC-AdV system that, under certain conditions, allows for significantly prolonged episomal maintenance of HC-AdV genomes in proliferating tissue culture cells, resulting in sustained transgene expression. After transduction of target cells the linear HC-AdV genomes were circularized by the DNA recombinase FLPe, which was expressed from the second HC-AdV. The
oriP
/EBNA-1 replication system derived from Epstein-Barr virus, as well as the human replication origin from the
lamin B2
locus, were used as
cis
elements to test for replication of the 28-kb circular vector genomes with or without selective pressure. Depending on the system, up to 98% of the circularized genomes were replicated and segregated to daughter cells, as demonstrated by Southern assays and as confirmed by monitoring
EGFP
transgene expression. Surprisingly, in the absence of FLPe recombinase, a small but significant number of HC-AdV genomes spontaneously circularized after transduction of target cells. These circles, found to contain end-to-end joined adenovirus termini, replicated with increased efficiency compared to vectors circularized by FLPe. After further improvements, this HC-AdV system might be suitable for gene therapy applications requiring long-term transgene expression.
Human Immunodeficiency Virus Type 1 Superinfection Was Not Detected following 215 Years of Injection Drug User Exposure
Authors: Tsui Rose , Herring Belinda L. , Barbour Jason D. , Grant Robert M. , Bacchetti Peter , Kral Alex , Edlin Brian R. , Delwart Eric L. 
Published: December 2003

ABSTRACT

Evidence for human immunodeficiency virus type 1 (HIV-1) superinfection was sought among 37 HIV-1-positive street-recruited active injection drug users (IDUs) from the San Francisco Bay area. HIV-1 sequences from pairs of samples collected 1 to 12 years apart, spanning a total of 215 years of exposure, were generated at p17
gag
, the V3-V5 region of
env
, and/or the first exon of
tat
and phylogenetically analyzed. No evidence of HIV-1 superinfection was detected in which a highly divergent HIV-1 variant emerged at a frequency >20% of the serum viral quasispecies. Based on the reported risk behavior of the IDUs and the HIV-1 incidence in uninfected subjects in the same cohort, a total of 3.4 new infections would have been expected if existing infection conferred no protection from superinfection. Adjusted for risk behaviors, the estimated relative risk of superinfection compared with initial infection was therefore 0.0 (95% confidence interval, 0.00, 0.79;
P
= 0.02), indicating that existing infection conferred a statistically significant level of protection against superinfection with an HIV-1 strain of the same subtype, which was between 21 and 100%.
Epidermal Homeostasis: The Role of the Growth Hormone and Insulin-Like Growth Factor Systems
Authors: Edmondson Stephanie R. , Thumiger Susan P. , Werther George A. , Wraight Christopher J. 
Published: December 2003

AbstractGH and IGF-I and -II were first identified by their endocrine activity. Specifically, IGF-I was found to mediate the linear growth-promoting actions of GH. It is now evident that these two growth factor systems also exert widespread activity throughout the body and that their actions are not always interconnected. The literature highlights the importance of the GH and IGF systems in normal skin homeostasis, including dermal/epidermal cross-talk. GH activity, sometimes mediated via IGF-I, is primarily evident in the dermis, particularly affecting collagen synthesis. In contrast, IGF action is an important feature of the dermal and epidermal compartments, predominantly enhancing cell proliferation, survival, and migration. The locally expressed IGF binding proteins play significant and complex roles, primarily via modulation of IGF actions. Disturbances in GH and IGF signaling pathways are implicated in the pathophysiology of several skin perturbations, particularly those exhibiting epidermal hyperplasia (e.g., psoriasis, carcinomas). Additionally, many studies emphasize the potential use of both growth factors in the treatment of skin wounds; for example, burn patients. This overview concerns the role and mechanisms of action of the GH and IGF systems in skin and maintenance of epidermal integrity in both health and disease.
Systemic and Local Regulation of the Growth Plate
Authors: van der Eerden B. C. J. , Karperien M. , Wit J. M. 
Published: December 2003

AbstractThe growth plate is the final target organ for longitudinal growth and results from chondrocyte proliferation and differentiation. During the first year of life, longitudinal growth rates are high, followed by a decade of modest longitudinal growth. The age at onset of puberty and the growth rate during the pubertal growth spurt (which occurs under the influence of estrogens and GH) contribute to sex difference in final height between boys and girls. At the end of puberty, growth plates fuse, thereby ceasing longitudinal growth. It has been recognized that receptors for many hormones such as estrogen, GH, and glucocorticoids are present in or on growth plate chondrocytes, suggesting that these hormones may influence processes in the growth plate directly. Moreover, many growth factors, i.e., IGF-I, Indian hedgehog, PTHrP, fibroblast growth factors, bone morphogenetic proteins, and vascular endothelial growth factor, are now considered as crucial regulators of chondrocyte proliferation and differentiation. In this review, we present an update on the present perception of growth plate function and the regulation of chondrocyte proliferation and differentiation by systemic and local regulators of which most are now related to human growth disorders.
The Calcimimetic Cinacalcet Normalizes Serum Calcium in Subjects with Primary Hyperparathyroidism
Authors: Shoback Dolores M. , Bilezikian John P. , Turner Stewart A. , McCary Laura C. , Guo Matthew D. , Peacock Munro 
Published: December 2003

AbstractCalcimimetics increase the sensitivity of the calcium-sensing receptor (CaR) to circulating serum calcium, reducing the secretion of PTH and the serum calcium concentration. We evaluated the calcimimetic cinacalcet, a novel therapy for the management of primary hyperparathyroidism. In this randomized, double-blind, dose-finding study, patients (n = 22) with primary hyperparathyroidism were given cinacalcet (30, 40, or 50 mg) or placebo twice daily for 15 d and observed for an additional 7 d. Serum calcium, plasma PTH, and 24-h and fasting urine calcium were measured. Baseline mean serum calcium was 10.6 mg/dl for the combined cinacalcet-treated patients (normal range, 8.4–10.3 mg/dl), compared with 10.4 mg/dl for the placebo group. Mean PTH at baseline was 102 pg/ml (normal range, 10–65 pg/ml) for the combined cinacalcet-treated patients, compared with 100 pg/ml in the placebo group. Serum calcium normalized after the second dose on d 1 and remained normal through d 15 in all cinacalcet dose groups. Maximum decreases in PTH of over 50% occurred 2–4 h after dosing in all cinacalcet-treated groups. The fasting and 24-h urine calcium to creatinine ratios were similar in the cinacalcet and placebo groups. This study demonstrates that cinacalcet safely normalized serum calcium and lowered PTH concentrations without increasing urinary calcium excretion in the study subjects, indicating the potential benefit of cinacalcet as a medical treatment for primary hyperparathyroidism.
Glucocorticoids and Insulin Sensitivity: Dissociation of Insulin’s Metabolic and Vascular Actions
Authors: Perry C. G. , Spiers A. , Cleland S. J. , Lowe G. D. O. , Petrie J. R. , Connell J. M. C. 
Published: December 2003

AbstractInsulin sensitivity in tissues such as a skeletal muscle and fat is closely correlated with insulin action in the vasculature, but the mechanism underlying this is unclear. We investigated the effect of dexamethasone on insulin-stimulated glucose disposal and vasodilation in healthy males to test the hypothesis that a reduction in glucose disposal would be accompanied by a reduction in insulin action in the vasculature. We performed a double-blind, placebo-controlled, cross-over trial comparing insulin sensitivity (measured by the euglycemic hyperinsulinemic clamp) and vascular insulin action (measured by small vessel wire myography) in young healthy males allocated to placebo or 1 mg dexamethasone twice daily for 6 d, each in random order. Six days of dexamethasone therapy was associated with a 30% (95% confidence interval, 19.1–40.0%) fall in insulin sensitivity. Despite this, there was no difference in insulin-mediated vasodilation between phases. Dexamethasone had no effect on circulating markers of endothelial function, such as d-dimer, von Willebrand factor, and tissue plasminogen activator. By short-term exposure to high dose dexamethasone we were able to differentially affect the metabolic and vascular actions of insulin. This implies that, using this model, there is physiological uncoupling of the effects of insulin in different tissues.
Exon 6 and 2 Peroxisome Proliferator-Activated Receptor-γ Polymorphisms in Polycystic Ovary Syndrome
Authors: Orio Francesco , Matarese Giuseppe , Di Biase Sebastiano , Palomba Stefano , Labella Donato , Sanna Veronica , Savastano Silvia , Zullo Fulvio , Colao Annamaria , Lombardi Gaetano 
Published: December 2003

Abstract
Obesity affects about 44% of women with polycystic ovary syndrome (PCOS). Peroxisome proliferator-activated receptor-γ (PPAR-γ) is one of the genes involved in the differentiation of adipose tissue. In an attempt to shed light on the high percentage of obesity in PCOS, we examined polymorphisms at exons 6 and 2 of the PPAR-γ gene in 100 PCOS patients and in 100 healthy controls matched for age and body mass index (BMI). The T allele frequency of exon 6 was significantly higher (P &lt; 0.05) in PCOS patients compared with control women. In addition, the BMI and leptin levels were significantly higher (P &lt; 0.05) in PCOS patients carrying the C→T substitution than in controls. There was no significant difference in leptin levels after normalization for BMI. The Pro12Ala polymorphism at exon 2 was unrelated to BMI and/or leptin levels in PCOS women. In conclusion, the higher frequency of the C→T substitution in exon 6 of the PPAR-γ gene in PCOS women suggests that it plays a role in the complex pathogenetic mechanism of obesity in PCOS, whereas the Pro12Ala polymorphism does not seem to affect BMI in PCOS women.
Identification of Adrenocorticotropin Receptor Messenger Ribonucleic Acid in the Human Pituitary and Its Loss of Expression in Pituitary Adenomas
Authors: Morris Damian G. , Kola Blerina , Borboli Ninetta , Kaltsas Gregory A. , Gueorguiev Maria , McNicol Anne Marie , Ferrier Roderick , Jones T. Hugh , Baldeweg Stephanie , Powell Michael , Czirják Sándor , Hanzély Zoltán , Johansson Jan-Ove , Korbonits Márta , Grossman Ashley B. 
Published: December 2003

Abstract
The ACTH receptor (ACTH-R) is the second member of the melanocortin (MC-2) receptor family that includes five seven-transmembrane G protein-coupled receptors and has been shown to be predominantly expressed in the adrenal cortex. It has been postulated that ACTH may regulate its own secretion through ultra-short-loop feedback within the pituitary. ACTH-secreting adenomas are characterized by resistance to glucocorticoid feedback, and they may have dysregulated ACTH feedback. We therefore investigated the ACTH-R in normal and adenomatous human pituitary tissue. We report here the identification of ACTH-R mRNA in the human pituitary gland, which was confirmed by direct sequencing. We studied the expression of the ACTH-R in 23 normal pituitary specimens and 53 pituitary adenomas (22 ACTH-secreting, nine GH-secreting, eight prolactin-secreting, one TSH-secreting, one FSH-secreting, 10 nonfunctioning, and two silent corticotroph adenomas), using the sensitive technique of real-time quantitative PCR. Contamination of ACTH-secreting adenomas and nonfunctioning pituitary adenomas with nonadenomatous tissue was excluded by lack of Pit-1 expression. ACTH-R mRNA was detected in all normal pituitary specimens, and in situ hybridization colocalized expression to ACTH staining cells only. However, ACTH-R mRNA levels were undetectable in 16 of 22 ACTH-secreting tumors and in both silent corticotroph tumors. Diagnostic preoperative plasma ACTH levels were significantly lower in the ACTH-R positive ACTH-secreting tumors, compared with those who were ACTH-R negative (P = 0.0006). Direct sequencing of the coding region of the ACTH-R in cDNA from three ACTH-secreting tumors positively expressing the receptor showed no mutations, as did sequencing of genomic DNA in three receptor negative ACTH-secreting tumors and the two silent corticotrophs. These results provide further evidence compatible with an ACTH feedback loop in the pituitary and suggest that loss of expression of the ACTH-R in corticotroph adenomas of patients with Cushing’s disease may play a role in the resistance to feedback of the pituitary-adrenal axis seen in these patients.
CYP21 Genotype, Adult Height, and Pubertal Development in 55 Patients Treated for 21-Hydroxylase Deficiency
Authors: Balsamo Antonio , Cicognani Alessandro , Baldazzi Lilia , Barbaro Michela , Baronio Federico , Gennari Monia , Bal Milva , Cassio Alessandra , Kontaxaki Krissi , Cacciari Emanuele 
Published: December 2003

Abstract
In a retrospective study we evaluated long-term growth, pubertal developmental patterns to final height (FH), and medication in 55 patients (35 females) affected by 21-hydroxylase deficiency. The patients were classified into 3 groups according to predicted mutation severity: group A (11 women and 9 men), homozygous or compound heterozygous for null or In2 splice mutations [residual enzymatic activity (RA), &lt;1%]; group B (11 women and 4 men), homozygous for I172N or R341P or R426H mutations (RA, ∼2–3%) or compound heterozygous with any of the group A or B mutations; and group C (13 women and 7 men), homozygous for P30L or V281L or P453S mutations (RA, &gt;30%) or compound heterozygous with any of the group A, B, or C mutations. Three patients showed unclassifiable genotypes. FH was similar in the female groups, whereas male patients in group B were shorter than males in groups A and C. Fifty-five percent of patients in group A, 33% in group B, and 40% in group C reached an FH within 0.5 sd of target height. Four of the 7 patients diagnosed via neonatal screening achieved an FH equal to or above the target height. In the entire group, early diagnosis (&lt;1 yr) improved height outcome. Early diagnosed CAH patients who received lower cortisol equivalent doses during the first year of life reached a better FH. Our results underline the importance of mineralocorticoid therapy, as CAH subjects in groups A and B who did not receive this treatment showed reduced FH. Early diagnosis, the use of more physiological cortisol equivalent dosages during the first year of life, and the extension of mineralocorticoid therapy to all classical patients are shown to improve the auxological outcome. Genotypic analysis helped to interpret the height results of our cases and prospectively may represent a useful tool for improving the therapeutic choice and the height outcome.
Acute Exposure to Circularly Polarized 50-Hz Magnetic Fields of 200–300 μT Does Not Affect the Pattern of Melatonin Secretion in Young Men
Authors: Warman G. R. , Tripp H. , Warman V. L. , Arendt J. 
Published: December 2003

Abstract
Environmental exposure to time-varying (alternating current) magnetic fields (MFs) produced by electrical current flow is a perceived public health risk. Several epidemiological studies report correlations between MF exposure and carcinogenesis. It has been hypothesized that MF-induced suppression of melatonin could provide the mechanism by which this effect is mediated. Here, we describe results from a controlled laboratory-based study designed to detect changes in human melatonin secretion after a 2-h exposure to 200–300 microTesla, 50 Hz circularly polarized MF. Exposure was timed to occur before or during the nightly melatonin rise, and levels administered were some 4–6 times higher than the commonly encountered maximum levels. Results from 19 male subjects aged between 18 and 35 yr indicate that acute exposure to 50 Hz MFs of this nature does not result in significant suppression, alteration of peak levels, or a change in timing of the nighttime melatonin rise. We conclude that acute exposure to 50 Hz MFs does not have a significant effect on the normal nighttime production of melatonin in young men.
Leptin and Bone Mineral Density: A Cross-Sectional Study in Obese and Nonobese Men
Authors: Morberg Cathrine M. , Tetens Inge , Black Eva , Toubro Soeren , Soerensen Thorkild I. A. , Pedersen Oluf , Astrup Arne 
Published: December 2003

Abstract
Leptin has been suggested to decrease bone mineral density (BMD). This observational analysis explored the relationship between serum leptin and BMD in 327 nonobese men (controls) (body mass index 26.1 ± 3.7 kg/m2, age 49.9 ± 6.0 yr) and 285 juvenile obese men (body mass index 35.9 ± 5.9 kg/m2, age 47.5 ± 5.1 yr). Whole-body dual-energy x-ray absorptiometry scan measured BMD, fat mass, and lean mass. Fasting serum leptin (nanograms per milliliter) was strongly associated with fat mass (kilograms) in both controls (r = 0.876; P &lt; 0.01) and juvenile obese (r = 0.838; P &lt; 0.001). An inverse relation between BMD adjusted for body weight and serum leptin emerged in both the control group (r = −0.186; P &lt; 0.01) and the juvenile obese group (r = −0.135; P &lt; 0.05). In a multiple linear regression, fat mass, lean body mass, and occupational physical activity were positively associated with BMD in the control group, whereas in the juvenile obese, only lean body mass was positively associated with BMD and smoking negatively associated with BMD. Our study supports that leptin is inversely associated with BMD and may play a direct role in the bone metabolism in nonobese and obese Danish males, but it also stresses the fact that the strong covariation between the examined variables is a shortcoming of the cross-sectional design.
Puberty in Growth Hormone-Treated Children Born Small for Gestational Age (SGA)
Authors: Boonstra Venje , van Pareren Yvonne , Mulder Paul , Hokken-Koelega Anita 
Published: December 2003

AbstractSeventy-five small for gestational age (SGA) children were studied in a randomized, double-blind, dose-response GH trial with either 1 or 2 mg GH/m2·d. Mean (sd) age at the start of GH therapy was 7.3 (2.2) yr. Data were compared with Dutch reference data.In SGA boys, mean (sd) age at onset of puberty was 12.0 (1.0) and 11.6 (0.7) yr, and in SGA girls it was 10.9 (1.1) and 10.6 (1.2) yr when treated with 1 and 2 mg GH/m2·d, respectively. SGA boys treated with the lower GH dose started puberty later than the appropriate for gestational age (AGA) controls; for the other GH-dosage groups there was no significant difference in age at onset of puberty compared to AGA controls. The age at menarche and the interval between breast stage M2 and menarche were not significantly different for GH-treated SGA girls compared to their peers. The duration of puberty and pubertal height gain of GH-treated SGA boys and girls were not significantly different between the two GH-dosage groups and were comparable with untreated short children born SGA.In conclusion, long-term GH therapy in short SGA children has no influence on the age at onset and progression of puberty compared to AGA controls, regardless of treatment with a dose of 1 or 2 mg GH/m2·d. Duration of puberty and pubertal height gain were not significantly different between the GH-dosage groups.
Cyclical Cushing’s Syndrome in a Patient with a Bronchial Neuroendocrine Tumor (Typical Carcinoid) Expressing Ghrelin and Growth Hormone Secretagogue Receptors
Authors: Arnaldi G. , Mancini T. , Kola B. , Appolloni G. , Freddi S. , Concettoni C. , Bearzi I. , Masini A. , Boscaro M. , Mantero F. 
Published: December 2003

Abstract
A 56-yr-old woman was referred with a diagnosis of Cushing’s disease. Hypertension and severe hypokalemia were present and high urinary free cortisol/cortisone ratio was detected, raising a suspicion of an ectopic ACTH syndrome. Inferior petrosal sinus sampling, thoracic computed tomography, and octreotide scans were negative. Remission and relapse periods lasting 3–4 months were observed during the 3.5 yr of follow-up. Finally a thoracic computed tomography scan showed a basal paracardic nodule in the left lung. After surgery, a well-differentiated neuroendocrine tumor (typical bronchial carcinoid) was diagnosed, staining positively for ACTH. RT-PCR revealed expression of proopiomelanocortin, CRH receptor, and V3 vasopressin receptor. Somatostatin receptor type 1, 2, 3, and 5 mRNA was detected only in tumoral tissue. Interestingly, we observed the simultaneous presence of ghrelin and both GH secretagogue (GHS) receptors (1a and 1b) mRNA in tumoral tissue but not in the normal lung. This finding correlates with the in vivo ACTH hyperresponsiveness to hexarelin (a GHS).
This is the first report of a cyclical ectopic ACTH-secreting tumor with an in vivo ACTH response to hexarelin coupled with the tumoral expression of ghrelin and GHS receptors. This finding might imply an autocrine/paracrine modulatory effect of ghrelin in bronchial ACTH-secreting tumors.