Journal of Long-term Effects of Medical Implants 

About: Journal of Long-term Effects of Medical Implants is an academic journal published by Begell House. The journal publishes majorly in the area(s): Medicine & Implant. It has an ISSN identifier of 1050-6934. Over the lifetime, 803 publications have been published receiving 10265 citations. The journal is also known as: Long term effects of medical implants & Journal of long term effects of medical implants.

Cholelithiasis and cholecystitis.

Abstract: Gallstone disease remains one of the most common medical problems leading to surgical intervention. Every year, approximately 500,000 cholecystectomies are performed in the US. Cholelithiasis affects approximately 10% of the adult population in the United States. It has been well demonstrated that the presence of gallstones increases with age. An estimated 20% of adults over 40 years of age and 30% of those over age 70 have biliary calculi. During the reproductive years, the female-to-male ratio is about 4:1, with the sex discrepancy narrowing in the older population to near equality. The risk factors predisposing to gallstone formation include obesity, diabetes mellitus, estrogen and pregnancy, hemolytic diseases, and cirrhosis. A study of the natural history of cholelithiasis demonstrates that approximately 35% of patients initially diagnosed with having, but not treated for, gallstones later developed complications or recurrent symptoms leading to cholecystectomy. During the last two decades, the general principles of gallstone management have not notably changed. However, methods of treatment have been dramatically altered. Today, laparoscopic cholecystectomy, laparoscopic common bile duct exploration, and endoscopic retrograde management of common bile duct (CBD) stones play important roles in the treatment of gallstones. These technological advances in the management of biliary tract disease are not infrequently accomplished by a multidisciplinary team of physicians, including surgeons trained in laparoscopic techniques, interventional gastroenterologists, and interventional radiologists. With the evolution of laparoscopic cholecystectomy, there has been a global reeducation and retraining program of surgeons. However, the treatment of choice for gallstones remains cholecystectomy. In recognition of the revolutionary advances in the treatment of cholelithiasis, it is the purpose of this collective review to describe recent information on the following topics: types of gallstones, asymptomatic gallstones, symptomatic gallstones, chronic cholecystitis, acute cholecystitis, and other complications of gallstones. Gross and compositional analysis of gallstones allows them to be classified as cholesterol, mixed, and pigment gallstones. When asymptomatic gallstones are detected during the evaluation of a patient, a prophylactic cholecystectomy is normally not indicated because of several factors. Only about 30% of patients with asymptomatic cholelithiasis will warrant surgery during their lifetime, suggesting that cholelithiasis can be a relatively benign condition in some people. However, there are certain factors that predict a more serious course in patients with asymptomatic gallstones and warrant a prophylactic cholecystectomy when they are present. These factors include patients with large (>2.5 cm) gallstones, patients with congenital hemolytic anemia or nonfunctioning gallbladders, or during bariatric surgery or colectomy. Epigastric and right upper quadrant pain occurring 30-60 minutes after meals is frequently associated with gallstone disease. The diagnosis of chronic cholecystitis is made by the presence of biliary colic with evidence of gallstones on an imaging study. Ultrasonography is the diagnostic test of choice, being 90-95% sensitive. The surgical literature suggests that 3-10% of patients undergoing cholecystectomy will have CBD stones. Intraoperative laparoscopic ultrasonography has recently replaced cholangiography as the method of choice for detecting CBD stones. Ultrasonography and radionuclide cholescintigraphy (HIDA scan) are useful in establishing a diagnosis of acute cholecystitis. Laparoscopic cholecystectomy should also be used in the treatment of acute cholecystitis. Laparoscopic cholecystectomy is more likely to be successful when performed within 3 days of the onset of symptoms. It is important to remember that gallstones can lead to a variety of other complications including choledocholithiasis, gallstone ileus, and acute gallstone pancreatitis.

PMMA: an essential material in medicine and dentistry.

Abstract: The first use of polymethyl methacrylate (PMMA) as a dental device was for the fabrication of complete denture bases Its qualities of biocompatibility, reliability, relative ease of manipulation, and low toxicity were soon seized upon and incorporated by many different medical specialties PMMA has been used for (a) bone cements; (b) contact and intraocular lens; (c) screw fixation in bone; (d) filler for bone cavities and skull defects; and (e) vertebrae stabilization in osteoporotic patients The many uses of PMMA in the field of medicine will be the focus of this review, with particular attention paid to assessing its physical properties, advantages, disadvantages, and complications Although numerous new alloplastic materials show promise, the versatility and reliability of PMMA cause it to remain a popular and frequently used material

BIO-OSS--a resorbable bone substitute?

Abstract: BIO-OSS is an allergen-free bone substitute material of bovine origin, used to fill bone defects or to reconstruct ridge configurations. Seventy one patients (39 female, 32 male) received 126 BIO-OSS implantations. Some health parameters or habits were documented to eliminate possible risk factors of influence. The diameter of jaw defects filled with BIO-OSS was measured. There was a significant influence of the defect size on the healing result. In X-ray controls, BIO-OSS served to identify the surrounding native bone. The density of the BIO-OSS areas was higher than in control sites. These radiological results were supported by bone biopsies. Histologically, the permanency of the BIO-OSS was still recognizable after 6 years and longer. The ingrowth of newly formed bone in the BIO-OSS scaffold explained the increased density of the implanted regions. There were no clinical signs of BIO-OSS resorption. Therefore, we can assume that form corrections achieved by BIO-OSS insertions will last.

Analysis of mammalian connective tissue: relationship between hierarchical structures and mechanical properties.

Abstract: It is widely accepted that the mechanical properties of implants must match those of the surrounding connective tissue to prevent stress concentration and premature failure. The purpose of this paper is to review the structure-mechanical property relationships that exist for connective tissue. The mechanical properties of connective tissue depend on the content of collagen, elastic tissue, and proteoglycans, as well as the geometric arrangement of the fibrous components, age, and location of the specimen. To a first approximation the geometry and loading pattern of the collagen networks in these tissues dominate the mechanical response at high strains. The behavior of the elastic fiber networks dominate the low-strain mechanical response in tissues where energy and shape recovery are critical. Proteoglycans are involved in resisting tissue compressive forces. Since the stiffness of connective tissue increases with age, it is necessary to attempt to match this property by designing implants that have similar behaviors to insure that stress concentration does not occur at the interface between the implant and host.

Cell adhesion to biomaterials: correlations between surface charge, surface roughness, adsorbed protein, and cell morphology.

Abstract: Adhesion of cells to a biomaterial surface can be a major factor mediating its biocompatibility. In this investigation, jet impingement techniques were used to quantify strength of cellular adhesion to various material surfaces. The metals tested: HS25 (a cobalt-based alloy similar to F75), 316L stainless steel, Ti-6Al-4V, and commercially pure tantalum, exhibited nearly a fivefold increase in adhesion strength above that characteristic of the polymeric materials tested (PTFE, silicone rubber, and HDPE). The present study examines physical and biological factors that might influence fibroblast adhesion to the biomaterial surface. The relation between surface charge and cellular adhesion was investigated in a controlled manner by measuring adhesion strength over a range of charge densities. The cells showed charge and electrical potential-dependent adhesion maxima, suggesting that surface alloying for optimum adherence may be possible. In a preliminary series of experiments adsorbed serum protein layers on a series of materials of differing adherence were investigated using gel electrophoresis to assess protein composition. Analysis of adsorbed proteins revealed little difference in relative abundance or total adsorption quantity. SEM micrographs of cells on Ti-6Al-4V and silicone rubber (high and low adhesion materials, respectively) demonstrated differences in cell morphology and cell density.