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Early Attempts (early + attempt)

Distribution by Scientific Domains

Medical Sciences	66%

Selected Abstracts

Prostanoids induce egr1 gene expression in cementoblastic OCCM cells

JOURNAL OF PERIODONTAL RESEARCH, Issue 5 2007
L. Pham
Background and Objective:, Prostanoids that activate protein kinase C signaling are potent anabolic stimulators of cementoblastic OCCM cells. Using cDNA subtractive hybridization, we identified early growth response gene-1 (egr1) as a prostanoid-induced gene. Egr1, a zinc-finger transcription factor expressed during tooth development, regulates cell growth and differentiation. We hypothesize that Egr1 may mediate part of the prostanoid-induced anabolic effect in cementoblasts. Our objective was to characterize prostanoid-induced egr1 gene expression in OCCM cells. Material and Methods:, Total RNA and proteins were assayed by northern blot and western immunoblot assays. Results:, Prostaglandin E2 -, prostaglandin F2, - and fluprostenol-induced egr1 mRNA levels peaked at 0.5 h and returned to baseline by 4 h. Prostaglandin F2, and fluprostenol more potently induced egr1 compared with prostaglandin E2. The phorbol ester, phorbol 12-myristate 13-acetate, which activates protein kinase C signaling, induced egr1 mRNA levels 66-fold over the control, whereas forskolin (a cAMP-protein kinase A activator) and ionomycin (a calcium activator) had no effect. Protein kinase C inhibition significantly inhibited prostaglandin E2 -, prostaglandin F2, - and fluprostenol-induced egr1 mRNA levels. Finally, prostanoids maximally induced Egr1 protein at 1 h. Conclusion:,egr1 is a primary response gene induced by prostaglandin E2, prostaglandin F2, and fluprostenol in OCCM cells through protein kinase C signaling, suggesting that Egr1 may be a key mediator of anabolic responses in cementoblasts. Cementum is vital for periodontal organ maintenance and regeneration. Periodontal ligament fibers (Sharpey's fibers) insert into bone and cementum, thereby supporting the tooth in the alveolus (1). If the periodontal organ is lost, its regeneration requires cementoblast differentiation in order to form new cementum for periodontal ligament fiber insertion. Early attempts to regenerate cementum have proven difficult and rarely generate sufficient tissue (2). A better understanding of the molecular and cellular regulators that promote cementoblast differentiation is critical for developing targeted periodontal regeneration. [source]

Cholestatic liver disease: pathophysiology and therapeutic options

LIVER INTERNATIONAL, Issue 2002
AF. Hofmann
Abstract: Cholestasis results from defective canalicular secretion of bile or obstruction to bile flow distal to the canaliculus. In early primary biliary cirrhosis, bile secretion continues, because of the secretory pressure of bile or because some ductules are not obstructed. With complete cholestasis, a bile acid deficiency occurs in the small intestinal lumen leading to lipid maldigestion and fat-soluble vitamin malabsorption. Bacterial proliferation, bacterial translocation to lymph nodes and endotoxemia may also occur leading to an acute phase reaction. Retention of bile acids in the hepatocyte leads to apoptosis. Accumulation of bile acids in the systemic circulation leads to pruritus, and may contribute to endothelial injury in the lungs and kidney. Early attempts to mimic hepatic excretory function by hemoperfusion over adsorbent columns were unsuccessful for a variety of reasons. Extracorporeal dialysis against albumin offers promise of a realistic albeit partial simulation of hepatic excretory function. [source]

Historical Review of Penile Prosthesis Design and Surgical Techniques: Part 1 of a Three-Part Review Series on Penile Prosthetic Surgery

THE JOURNAL OF SEXUAL MEDICINE, Issue 3 2009
Gerard D. Henry MD
ABSTRACT Introduction., Throughout history, many attempts to cure complete impotence have been recorded. Early attempts at a surgical approach involved the placement of rigid devices to support the natural process of erection formation. However, these early attempts placed the devices outside of the corpora cavernosa, with high rates of erosion and infection. Today, most urologists in the United States now place an inflatable penile prosthesis (IPP) with an antibiotic coating inside the tunica albuginea. Aim., The article describes the key historical landmarks in penile prosthesis design and surgical techniques. Methods., The article reviews and evaluates the published literature for important contributions to penile prosthesis design and surgical techniques. Main Outcome Measures., The article reviews and evaluates the historical landmarks in penile prosthesis design and surgical techniques that appear to improve outcomes and advance the field of prosthetic urology for the treatment of erectile dysfunction. Results., The current review demonstrates the stepwise progression starting with the use of stenting for achieving rigidity in the impotent patient. Modern advances were first used in war-injured patients which led to early implantation with foreign material. The design and techniques of penile prostheses placement have advanced such that now, more complications are linked to medical issues than failure of the implant. Conclusions., Today's IPPs have high patient satisfaction rates with low mechanical failure rates. Gerard D. Henry. Historical review of penile prosthesis design and surgical techniques: Part 1 of a three-part review series on penile prosthetic surgery. J Sex Med 2009;6:675,681. [source]

The androgenic gland and monosex culture of freshwater prawn Macrobrachium rosenbergii (De Man): a biotechnological perspective

AQUACULTURE RESEARCH, Issue 3 2005
Amir Sagi
Abstract Males of the freshwater prawn Macrobrachium rosenbergii (De Man) grow faster and reach a larger size at harvest than females of the species. It is thus obvious that culture of monosex all-male populations would be economically advantageous. Sexual differentiation in crustaceans is regulated by the androgenic gland (AG), which plays a pivotal role in the regulation of male differentiation and in the inhibition of female differentiation. In M. rosenbergii, AG removal from immature males resulted in sex reversal, with complete female differentiation. Similarly, AG implantations into immature females lead to the development of the male reproductive system. Sex-reversed M. rosenbergii animals were capable of mating with normal specimens to produce offspring. Early attempts in Israel and more recently, attempts in other countries to establish all-male populations through manual segregation showed that for the production of monosex prawn populations to be economically feasible, intervention via the AG is probably required. However, a suitable biotechnology is still to be developed, and an androgenic hormone has yet to be identified in decapods. Three lines of aquacultural and biotechnological research and development are proposed for the future: (1) Establishment of monosex cultures through manual segregation, together with the application of selective harvesting and claw ablation, as well as examination of different monosex culture strategies under a variety of economic conditions. (2) Microsurgical intervention in the AG, leading to the development of functional neo-females, which would subsequently be mated with normal males to produce all-male progeny. (3) Elucidation of AG bioactive products to enable biochemical or molecular manipulation of sex differentiation. [source]

Diagnosis and classification of periodontal disease

AUSTRALIAN DENTAL JOURNAL, Issue 2009
J Highfield
Abstract Periodontal diseases have been recognized and treated for at least 5000 years. Clinicians have recognized for many years that there are apparent differences in the presentation of periodontal diseases and have attempted to classify these diseases. Systems of classifications of disease have arisen allowing clinicians to develop structures which can be used to identify diseases in relation to aetiology, pathogenesis and treatment. It allows us to organize effective treatment of our patients' diseases. Once a disease has been diagnosed and classified, the aetiology of the condition and appropriate evidence-based treatment is suggested to the clinician. Common systems of classification also allow effective communication between health care professionals using a common language. Early attempts at classification were made on the basis of the clinical characteristics of the diseases or on theories of their aetiology. These attempts were unsupported by any evidence base. As scientific knowledge expanded, conventional pathology formed the basis of classification. More recently, this has been followed by systems of classification based upon our knowledge of the various periodontal infections and the host response to them. Classification of periodontal diseases has, however, proved problematic. Over much of the last century clinicians and researchers have grappled with the problem and have assembled periodically to review or develop the classification of the various forms of periodontal disease as research has expanded our knowledge of these diseases. This has resulted in frequent revisions and changes. A classification, however, should not be regarded as a permanent structure. It must be adaptable to change and evolve with the development of new knowledge. It is expected that systems of classification will change over time. This review examines the past and present classifications of the periodontal diseases. [source]

User involvement in developing mobile and temporarily interconnected systems

INFORMATION SYSTEMS JOURNAL, Issue 2 2010
Ola Henfridsson
Abstract Information systems (IS) research on user involvement has primarily theorized relationships between developers, managers and users in systems development. However, so far, marginal attention has been paid to differences in user involvement practices between information systems. This paper explores user involvement in developing mobile and temporarily interconnected systems (MTIS). We refer to MTIS as heterogeneous systems that rely on network technologies for increasing the ubiquity of information services for users on the move. Such systems are becoming increasingly important in leveraging, e.g. car infotainment, supply chain management and wireless e-commerce. With particular emphasis on the nature of MTIS and its implications for user involvement, the paper analyses the systems development process of an action research project. The findings suggest that user involvement practices need to be adapted to accommodate features of this class of systems. Being an early attempt to trace the implications of technology features such as use context switches and temporary system relationships, the paper contributes to the development of an updated theory of the user role in an era of increased system complexity and stakeholder ambiguity. [source]

Agriculture and ,Improvement' in Early Colonial India: A Pre-History of Development

JOURNAL OF AGRARIAN CHANGE, Issue 4 2005
DAVID ARNOLD
The doctrine of ,improvement' has often been identified with the introduction , and presumed failure , of the Permanent Settlement in Bengal in 1793. Although recognized as central to British agrarian policies in India, its wider impact and significance have been insufficiently explored. Aesthetic taste, moral judgement and botanical enthusiasm combined with more strictly economic criteria to give an authority to the idea of improvement that endured into the middle decades of the nineteenth century. Concern for improvement also reflected dissatisfaction with India's apparent poverty and deficient material environment; it helped stimulate data-collection and ambitious schemes of agrarian transformation. A precursor of later concepts of development, not least in its negative presumptions about India and the search for external agencies of change, improvement yet shows many of the false starts and intrinsic limitations early attempts to transform rural India entailed. This article reassesses the significance of improvement in the first half of the nineteenth century in India, especially as illustrated through contemporary travel literature and through the aims and activities of the Agricultural and Horticultural Society of India. [source]

Development, principles, and applications of automated ice fabric analyzers

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2003
L.A. Wilen
Abstract We review the recent development of automated techniques to determine the fabric and texture of polycrystalline ice. The motivation for the study of ice fabric is first outlined. After a brief introduction to the relevant optical concepts, the classic manual technique for fabric measurement is described, along with early attempts at partial automation. Then, the general principles behind fully automated techniques are discussed. We describe in some detail the similarities and differences of the three modern instruments recently developed for ice fabric studies. Next, we discuss briefly X-ray, radar, and acoustic techniques for ice fabric characterization. We also discuss the principles behind automated optical techniques to measure fabric in quartz rock samples. Finally, examples of new applications that have been facilitated by the development of the ice fabric instruments are presented. Microsc. Res. Tech. 62:2,18, 2003. © 2003 Wiley-Liss, Inc. [source]