Hydroxyapatite and calcium phosphate coatings on aluminium oxide orbital implants

BACKGROUND: Hydroxyapatite and calcium phosphate have been used as bone graft substitutes as they facilitate and promote tissue ingrowth. We carried out a study to examine uncoated and coated aluminium oxide (alumina) spherical orbital implants and assess whether the coatings influence fibrovascular ingrowth. METHODS: The aluminium oxide spheres (three coated with hydroxyapatite, three coated with calcium metaphosphate and three uncoated) were manufactured at the School of Materials Engineering, Yeungnam University, Kyongsan, Kyongbuk, Korea. The implants were examined macroscopically and with scanning electron microscopy and were analysed chemically by means of x-ray powder diffraction and x-ray fluorescence spectrophotometry. Implantation of three hydroxyapatite-coated, three calcium metaphosphate-coated and three uncoated aluminium oxide spheres was done in nine adult male New Zealand albino rabbits. Implant vascularization was evaluated at 4, 8 and 12 weeks by means of histopathological sectioning. RESULTS: All three types of implant had multiple interconnected pores. The coatings increased the size of the trabeculae from 150 microm to 300 microm. As a result, the pores appeared slightly smaller but still ranged in size from 300 microm to 750 microm, compared to 400 microm to 800 microm in the uncoated implants. The coatings also increased the weight of the implants slightly. The implants were all strong mechanically. They were made up primarily of aluminium oxide. The coated implants contained significant amounts of calcium oxide (a contaminant). There was no clinical difference in the socket response between the three groups. Histopathologically, fibrovascularization occurred uniformly throughout each implant at 4, 8 and 12 weeks after implantation. INTERPRETATION: The hydroxyapatite and calcium metaphosphate coatings did not appear to facilitate or inhibit fibrovascular ingrowth at 4, 8 and 12 weeks. Longer-term studies are need to determine whether the coatings play a role in long-term acceptance and retention of the implants.     

Tau protein phosphorylation as a therapeutic target in Alzheimer's disease

Neurofibrillary tangles (NFTs) are a distinguishing neuropathological feature found in postmortem brains of Alzheimer s disease (AD) and tauopathy patients. The density of these lesions correlates with severity of AD and their distribution follows a characteristic pattern of expansion as the disease progresses. The principle components of NFTs are highly phosphorylated forms of the microtubule-associated protein, tau. Tau phosphorylation is believed to initiate or facilitate dissociation from microtubules leading to microtubule destabilization, decay of cellular transport properties, and cell death. This review summarizes recent data and prevailing views on the roles of protein kinases and phosphatases in the regulation of tau phosphorylation in vitro and in vivo, taking into account data from human neurodegenerative diseases and from transgenic rodent models. Small molecule inhibitors of tau phosphorylation that serve as important research tools and possibly the basis of potential new therapeutics, are also described. Key challenges in developing effective therapeutic agents include identification of the relevant kinase(s) responsible for aberrant tau phosphorylation in AD, synthesis of inhibitors selectively targeting those kinases and establishment of appropriate animal models.     

Choroidal bodies: a new structure in the fourth ventricular choroid plexus of the rat and mouse

Histologic study of the caudal end of the fourth ventricular choroid plexus of the rat and mouse revealed 1-4 small, discrete collections of cells that differed from the surrounding choroidal epithelial cells in appearance. They did not occur in other parts of the choroid plexuses. These choroidal bodies were not affected by a chemical toxin that caused hydropic degeneration of all the epithelial cells in the choroid plexuses. The function, if any, of the choroidal bodies is unknown. They were present in all rats that were studied by serial sections.     

Long-term treatment of an addictive personality

There is infrequent discussion of long-term psychotherapy of persons with addiction, particularly in the self-psychology literature. In addition, some question whether long-term psychotherapy can be helpful in severe psychiatric disorders. The author describes the treatment of a woman with multiple diagnoses, including bulimia and alcohol and drug addiction, which took place over a period of almost 7 years. These issues are addressed from a self-psychological perspective, with progression of the treatment from early facilitation of a selfobject transference to more intense selfobject transference-countertransference states. Behavioral interventions (e.g., recommendation of inpatient chemical dependency treatment) are also discussed. The author describes the patient's dramatic progress and subsequent regression. Finally, there is a discussion of the addiction from self-psychological and biological perspectives of this woman's particular developmental and treatment issues, as well as a discussion of the confrontation and limit setting in a self-psychologically oriented treatment.     

Management of the primary cutaneous lymphomas

Cutaneous lymphomas are rare and, although some are a manifestation of systemic lymphoma, the majority arise primarily from the skin. These primary cutaneous lymphomas comprise both T- and B-cell subtypes and represent a wide spectrum of disorders, which at times can be difficult to diagnose and classify. Classical therapeutic strategies include topical corticosteroids, phototherapy, radiotherapy, retinoids, extracorporeal photopheresis, topical chemotherapy, systemic chemotherapy and biological response modifiers. Newer therapies include the synthetic retinoid bexarotene, the immunotoxin conjugate denileukin diftitox, interleukin-12 and monoclonal antibodies such as alemtuzumab and rituximab.     

Toothache of nonodontogenic origin: a case report

This article describes the diagnosis and treatment of a patient exhibiting nonodontogenic tooth pain. A 25-yr-old female patient presented to postgraduate endodontics, SUNY at Stony Brook, for evaluation and treatment of pain associated with the upper and lower left quadrants. After thorough intraoral and extraoral examinations, it was determined that the pain was referred to the dentition from a trigger point in the masseter muscle. An extraoral injection of 3% Carbocaine was administered into the trigger point, and the pain abated within 5 min. The patient has experienced no recurrence of this pain for 12 months. Consideration of nonodontogenic dental pain should be included in a differential diagnosis.     

Individual prostate biopsy core embedding facilitates maximal tissue representation

PURPOSE: The probability of detecting small foci of prostate cancer is related to the amount of tissue represented. When multiple prostate biopsy cores are embedded in a single block, less tissue is evaluated because it is difficult to embed all cores in a single plane for optimal tissue representation. A computer simulation of sectioning biopsy cores was devised to examine the total surface area available at various angles of embedding and predict the ability to detect small tumor foci. MATERIALS AND METHODS: The computer simulation of biopsy core was done using commercially available software. Biopsy cores were represented as 3-dimensional cylindrical objects and the cutting blade was represented by a 2-dimensional plane. The intersection of the plane and cylinder represented the cut surface, which varied depending on cylinder angle and position. The simulation program calculates available surface area. RESULTS: Maximal surface area was obtained when the plane was horizontal to the long axis of the core. Any divergence of the cylinder from horizontal decreased the represented area. A single section through a 1 x 15 mm. biopsy core at 0 degrees yielded a surface area of 15 mm(2). The surface area was decreased to 13.3, 9.01 and 4.52 mm(2) at 3, 5 and 10 degrees, respectively. At a small focus of 0.6 mm. there was 100% detection under optimal circumstance, which decreased to 56.2% and 27.9% as the angle increased to 3 and 10 degrees, respectively. CONCLUSIONS: Optimal sectioning, that is maximal surface area, of the core is obtained when a biopsy core is sectioned at a 0-degree angle, that is horizontal to its long axis. It is much more likely when each biopsy core is embedded individually. When multiple cores are embedded together, it is difficult to position all cores in the same plane since cores move to different planes and the cut surface of the cylinders substantially decreases. Thus, for optimal surface representation and cancer detection embedding individual cores is appropriate.     

BAL findings in a patient with pulmonary alveolar proteinosis successfully treated with GM-CSF

BACKGROUND: Idiopathic pulmonary alveolar proteinosis (PAP) has recently been recognised as a disease of impaired alveolar macrophage function caused by neutralising anti-granulocyte-macrophage colony-stimulating (anti-GM-CSF) autoantibodies. Subcutaneous recombinant human GM-CSF is a novel treatment for PAP, but its mechanism of action is unclear. METHODS: Clinical, functional, and bronchoalveolar lavage (BAL) findings were prospectively evaluated in a patient with PAP treated with daily subcutaneous GM-CSF 8 microg/kg for 12 weeks. RESULTS: Treatment resulted in improvements in dyspnoea, lung function, and peak cycle ergometry performance. In serum and BAL fluid the titre of anti-GM-CSF autoantibodies was raised at baseline and markedly reduced on treatment. At baseline the BAL fluid cellular profile showed a decrease in the absolute number and the percentage of macrophages (50%) and an increase in lymphocytes (45%), predominantly CD4+. This cellular distribution remained unchanged after 6 and 12 weeks of treatment while macrophages became morphologically normal and functionally improved. Extracellular proteinaceous material completely disappeared. CONCLUSIONS: Clinically successful treatment of PAP with GM-CSF was associated with a profound reduction in GM-CSF neutralising autoantibodies, improvement in alveolar macrophage morphology and function, but persistent BAL lymphocytosis.     

Cdk5 as a drug target for the treatment of Alzheimer's disease

Cyclin-dependent kinase-5 (cdk5) is suggested to play a role in tau phosphorylation and contribute to the pathogenesis of Alzheimer’s disease (AD). One of its activators, p25, is dramatically increased in AD brains where p25 and cdk5 are colocalized with neurofibrillary tangles. Several animal models have shown a correlation of p25/cdk5 activities with tau phosphorylation. Overexpression of p25/cdk5 in nueronal cultures not only leads to tau phosphorylation but also cytoskeletal abnormalities and neurodegeneration. Therefore, cdk5 kinase inhibitors are potential therapeutic agents for the treatment of AD. Availability of potent, selective, brain permeable cdk5 inhibitors and relevant animal models in which their efficacy can be treated will be critical in the development of these inhibitors.