The association of different urinary proteins with calcium oxalate hydromorphs. Evidence for non-specific interactions.

It has been proposed that various urinary proteins interact specifically with different calcium oxalate hydromorphs and these interactions have important implications regarding the understanding of the onset and progress of kidney stone disease. Calcium oxalate monohydrate and dihydrate crystals were grown and characterised thoroughly to establish sample purity. These crystals were then incubated in artificial urine samples containing isolated urinary macromolecules. Crystal growth was prevented by saturating the incubation mix with calcium oxalate, and this was confirmed through electron microscopy and calcium measurements of the incubation mix. The surface interactions between the different calcium oxalate hydrates and urinary proteins were investigated by the use of Western blots and immunoassays. The same proteins, notably albumin, Tamm-Horsfall protein, osteopontin and prothrombin fragment 1, associated with both hydrates. There was a trend for more protein to associate with calcium oxalate dihydrate, and greater quantities of different proteins associated with both hydrates when Tamm-Horsfall protein was removed from the incubation mix. There is no evidence from this study to indicate that particular proteins interact with specific calcium oxalate hydrates, which in turn suggests that these protein-mineral interactions are likely to be mediated through non-specific charge interactions.

The density and protein content of calcium oxalate crystals precipitated from human urine: a tool to investigate ultrastructure and the fractional volume occupied by organic matrix.

One of the key debates in biomineralisation studies is the extent to which components of the organic matrix become occluded into the crystal lattice during growth. Here, the relationship between protein content and density of calcium oxalate crystals grown in human urine has been investigated in order to determine which fraction of crystal volume is non-mineral. The density of crystals varied from 1.84 to 2.08 g/cm3 while the protein content ranged from 0.1 to 2.1% (w/w). There was an inverse relationship between measured density and protein content which was qualitatively and quantitatively consistent with predictions based on reasonable densities for the mineral and non-mineral components. The coefficients of the fitted equation suggest that, at 2% protein (w/w), the volume of non-mineral would be 5.0% (v/v). The density values we observed are incompatible with fractional volumes of 20%. The results confirm that the occlusion of a small but possibly significant amount of protein into a crystal lattice is possible, but cast doubt on the hypothesis that protein acts as a major intracrystalline ultrastructural element. Moreover, the methodology developed for this study offers a simple and robust method for interrogating organic/inorganic associations in a range of biological and medical systems.

Enlargement of calcium oxalate stones to clinically significant size in an in-vitro stone generator.

OBJECTIVE: To develop and validate an in vitro method suitable for the quantitative investigation of the growth of calcium oxalate stones through to a clinically significant size. MATERIALS AND METHODS: Small fragments of calcium oxalate calculi were suspended in a mixed suspension/mixed product removal crystalliser supplied with artificial urine supersaturated with calcium oxalate. The fragments were weighed at regular intervals until they reached approximately equal 500 mg. The results were plotted as weight against time and fitted to equations corresponding to constant increase in diameter, surface area-controlled and constant-deposition growth patterns. The choice of the most appropriate model was based on the squared regression coefficient (r2). RESULTS: Eight fragments (2-6 mm in diameter) were grown to approximately 10 mm in diameter over periods from 137 to 369 h. Seven of the growth curves were best-fitted (r2 > or = 0.988) by the equation w = kt(3/2) + c, where w is the weight, k is a growth constant, t is the time and c is a constant approximating to the initial weight. This corresponds to a surface area-dependent mechanism. CONCLUSIONS: The growth of these small fragments to a clinically significant size accelerated throughout the experimental period in a way which was consistent with a surface area-dependent mechanism. We have developed a resilient model suitable for studying the kinetics of calcium oxalate stone growth in vitro.

Juvenile arthritis and autoimmunity to type II collagen.

OBJECTIVE: Joint inflammation in juvenile rheumatoid arthritis (JRA) is sometimes associated with an autoimmune response to type II collagen (CII), a cartilage-specific protein. To test the hypothesis that down-regulation of autoimmunity to CII can be accomplished in JRA by oral administration of CII, an open-label study of CII was performed in 9 patients with JRA. METHODS: Seven rheumatoid factor-negative JRA patients with polyarticular disease and 2 JRA patients with pauciarticular disease (1 with early onset and 1 with late onset) were treated for 3 months with oral bovine CII. Patients were examined for disease activity and underwent routine laboratory testing at monthly intervals. Two of the patients had flares of disease when treatment was discontinued, and these patients were re-treated for an additional 3 months. To test the hypothesis that oral tolerance induces an immune deviation of T cells, peripheral blood mononuclear cells from patients were collected before and after treatment and cultured with CII. Supernatants and RNA were collected and analyzed for the presence of various cytokines. RESULTS: Eight patient trials met the criteria for clinical improvement outlined by Giannini and coworkers in 1997. None of the patients had any side effects from the treatment. In 6 of the 8 patients who improved, interferon-gamma production decreased after oral CII therapy, correlating with clinical improvement, while 6 patients had increases in levels of transforming growth factor beta3. CONCLUSION: These results are encouraging. The possible beneficial effect of oral CII in JRA merits further investigation.

Setting times for endodontic sealers under clinical usage and in vitro conditions.

The object of this study was to determine the set of sealers under simulated clinical versus bench-top conditions. One hundred twenty extracted teeth were divided into four groups (Roth's, Tubuliseal, Sealapex, AH26). Canal preparation and lateral condensation were performed with the four sealers (30 teeth each). Teeth were placed into 100% humidity at 37 degrees C. The same mix of sealer on a glass slab was stored within the same environment. After 1 to 8 wk the teeth were fractured longitudinally to expose the gutta-percha-sealer interface. Evaluation, both clinical and in vitro, was qualitative under a microscope with a needle tip. The degree of set was categorized as: (a) unset (smearable), (b) partially set (indented easily, but not smearable), or (3) set (not easily indentable). There were inconsistencies in setting times within and between groups. In canals most of three (AH26, Sealapex, and Tubuliseal) were partially set after 1 wk; set was complete after 4 wk. Roth's was very slow; most were unset after 8 wk. Sealers on the glass slab set much more rapidly. In conclusion, under clinical conditions, sealers set slowly (particularly Roth's) and were more delayed than when tested in vitro.

Herpes zoster ophthalmicus following bone marrow transplantation in children.

Varicella zoster virus (VZV) infection is a frequent complication following bone marrow transplantation (BMT). Involvement of the ophthalmic division of the trigeminal nerve, herpes zoster ophthalmicus (HZO), can result in significant and potentially vision-threatening ocular complications. We report the frequency and characteristics of HZO following BMT, including the timing of infection, treatment, ocular complications, and visual outcome. Between 1983 and 1997, 572 patients underwent BMT and seven children developed HZO at a median of 150 days following transplantation. All but one of the children had undergone allogeneic BMT. All of the children were treated with acyclovir after onset of the rash but none had received prophylactic therapy. All seven children developed ocular complications within the first 4 weeks following the onset of the dermatomal rash but none reported any symptoms during this period. Complications included keratitis in six, anterior uveitis in three and scleritis in one. Keratitis was an early complication developing within the first 4 weeks, while anterior uveitis and scleritis occurred later in the course of the disease. The high frequency of ocular complications and lack of symptoms in children with HZO following BMT suggests that early ophthalmologic evaluation is warranted in this group of patients. Prompt diagnosis and treatment of ocular complications is essential in the prevention of acute and long-term ocular sequelae in these children.

Cyclosporine therapy for severe sight-threatening uveitis in children and adolescents.

OBJECTIVE: To review the safety and efficacy of cyclosporine in the treatment of children with severe bilateral sight-threatening intermediate uveitis or panuveitis. DESIGN/PARTICIPANTS: A retrospective chart review was performed on all children younger than 18 years of age with chronic bilateral sight-threatening uveitis who were treated with cyclosporine. MAIN OUTCOME MEASURES: Assessment of the therapeutic efficacy and development of adverse effects of cyclosporine after 6 months, 2 years, and 4 years of therapy was performed. RESULTS: Between 1983 and 1992, 15 children and adolescents were treated with cyclosporine. After 6 months, visual acuity improved or stabilized in 82.1% of eyes, while median vitreous inflammation decreased from 2.0 to 0.5. After 2 and 4 years, visual acuity improved or stabilized in 64% and 75% of eyes, respectively. Median vitreous inflammation remained 0.5 after 2 and 4 years of therapy. Mean creatinine clearance and hemoglobin values decreased and serum creatinine increased after 6 months. After 2 years, only mean hemoglobin values remained decreased. After 4 years, no significant differences were noted in any of the laboratory studies. The most frequently noted side effects included transient increases in serum creatinine in 53%, gingival hyperplasia in 40%, and hirsutism in 20% of patients. CONCLUSIONS: The authors' results suggest that cyclosporine is a safe and effective therapy for the treatment of children with severe bilateral sight-threatening intermediate uveitis or panuveitis.

Transient vitreous inflammatory reactions associated with combination antiretroviral therapy in patients with AIDS and cytomegalovirus retinitis.

PURPOSE: To report the observation that a transient vitreous inflammatory reaction may develop in the eyes of patients with acquired immunodeficiency syndrome (AIDS), cytomegalovirus retinitis, and an increased CD4+ T-lymphocyte count during treatment with antiretroviral therapy including a protease inhibitor. METHODS: We reviewed the medical records of eight patients with AIDS and cytomegalovirus retinitis who developed vitreous inflammatory reactions greater than those usually seen with this disease. RESULTS: Vitreous inflammatory reactions obscured the view of the posterior pole in all patients. No iris nodules, synechiae, glaucoma, or cystoid macular edema were observed. Six patients had unilateral cytomegalovirus retinitis, and, in each, the inflammation occurred only in the eye with cytomegalovirus retinitis. The vitreous inflammatory reactions were associated with clinically inactive cytomegalovirus retinitis in six patients, with disease reactivation in one patient, and were present at diagnosis of active disease in one patient. Cytomegalovirus retinitis has not recurred in any of these patients since their episodes of vitreous inflammation. Vitreous inflammation developed in all eight patients after a substantial increase in CD4+ T-lymphocyte counts caused by combination antiretroviral therapy. Five patients had CD4+ T-lymphocyte counts of greater than 100 cells per microl at the time the vitreous inflammatory reaction developed. No other causes of uveitis were found. CONCLUSIONS: Patients with AIDS and cytomegalovirus retinitis may develop transient intraocular inflammation associated with combination antiretroviral therapy. We believe that this inflammation reflects an improved immune response against cytomegalovirus.

Ganciclovir implant exchange. Timing, surgical procedure, and complications.

BACKGROUND: The ganciclovir implant is effective for the treatment of cytomegalovirus (CMV) retinitis. The device eventually runs out of drug, however, and must be replaced. We report our experience with exchanging ganciclovir implants during the course of a randomized clinical trial. METHODS: During our study, patients with newly diagnosed peripheral CMV retinitis were treated with a ganciclovir implant. The implant was scheduled for exchange at 32 weeks. It was exchanged earlier if progression of CMV retinitis occurred. Patient examinations and standard fundus photography were performed at 2-week intervals after the exchange procedure. RESULTS: Twenty-six exchange procedures were performed. Twenty-two eyes in 15 patients received a second implant and 4 eyes in 4 patients later received a third implant. Cytomegalovirus retinitis was rendered or maintained inactive in 22 of 23 cases with more than 1 month of follow-up after the second or third implants. Complications after the second implant procedure included transient vitreous hemorrhage in 5 eyes, postoperative inflammation in 1 eye, and retinal detachment in 1 eye. Median visual acuity returned to 20/25 by 28 days and to 20/20 by 42 days. Complications after the third implant procedure included dense vitreous hemorrhage in 3 of 4 eyes. Median survival time after a second implant procedure was 89 days. CONCLUSIONS: The initial ganciclovir implant exchange procedure is well tolerated with continued long-term control of CMV retinitis. Multiple reentries through the same wound may be associated with an increased risk for vitreous hemorrhage.

Combined ganciclovir and foscarnet in pediatric cytomegalovirus retinitis.

Cytomegalovirus retinitis is the leading cause of blindness in adults and children with acquired immunodeficiency syndrome (AIDS). Although clinical trials on therapy exist for adults, management of cytomegalovirus retinitis in children is not as well-documented. This report describes the clinical course of a 3-year-old child with cytomegalovirus retinitis. After initial failure with single-agent ganciclovir intravenous treatment, early institution of combined treatment with foscarnet and ganciclovir halted progression of the retinitis. This case report highlights the aggressive nature of cytomegalovirus retinitis in children and the consideration of early combined therapy compared to adult patients.

Rhabdomyosarcoma presumed metastatic to the orbit.

BACKGROUND: Orbital metastasis from rhabdomyosarcoma is a rare disorder with a poor prognosis for long-term survival. Only one other detailed account of this disorder has appeared in the ophthalmic literature. METHODS: The authors report the clinical features of four patients with presumed orbital metastasis from alveolar and embryonal rhabdomyosarcoma. RESULTS: The most common ophthalmic manifestations of orbital metastasis from rhabdomyosarcoma in these patients included proptosis, reduced visual acuity, orbital pain, and motility disorders. Computed tomography documented orbital masses in all of the patients. In those patients with a primary tumor of the maxillary sinus, there was no evidence of direct extension into the orbit. Despite combination chemotherapy and radiation, all four patients died of their illness within 6 months of orbital metastasis. CONCLUSIONS: Although uncommon, rhabdomyosarcoma should be considered in the differential diagnosis of metastatic tumors to the orbit in children and adults. Despite the poor prognosis, prompt diagnosis and palliative radiotherapy may improve the quality of life for these patients with terminal disease.

Primary retinal vasculitis. Systemic associations and diagnostic evaluation.

BACKGROUND: Inflammation of the retinal vasculature without an infectious etiology, systemic disease association, or concomitant ocular disease is termed primary retinal vasculitis, and can result in severe and permanent vision loss. Patients with primary retinal vasculitis usually are subjected to an extensive but unrewarding diagnostic evaluation. This study was undertaken to determine the value of such a diagnostic workup, and to determine whether systemic diseases develop in these patients during the course of their illness. METHODS: The clinical records of 25 patients seen between 1984 and 1994 with the referring diagnosis of primary retinal vasculitis were reviewed retrospectively. Recorded data included patient age, sex, race, medical history, medications, visual acuity, extent of retinal disease, and the results of their diagnostic evaluations. RESULTS: On presentation, none of the patients had an underlying systemic disease attributable as the cause of their retinal vasculitis. Review of systems was suggestive of an underlying systemic disease in 1 of 25 patients. Diagnostic evaluation in this patient showed a positive antinuclear antibody value and a double-stranded DNA, suggestive of systemic lupus erythematosus. Subsequently, systemic lupus erythematosus was diagnosed based on the development of other diagnostic criteria. The review of systems was not suggestive of an underlying systemic disease in 24 of 25 patients. False-positive diagnostic test results were obtained in 5 (20.8%) of these 24 patients. No underlying systemic disease associated with the patients' retinal vasculitis subsequently developed in any of these five patients (mean follow-up, 4 years). CONCLUSION: Few diagnostic tests should be ordered in patients with retinal vasculitis in the absence of a medical history suggestive of underlying systemic disease.

Fluorescein angiography in the progressive outer retinal necrosis syndrome.

PURPOSE: Progressive outer retinal necrosis syndrome is a devastating retinopathy seen primarily in patients with acquired immune deficiency syndrome. To provide additional details of the pathogenesis of this disease, the authors describe the evolution of clinical and fluorescein angiographic changes during the course of progressive outer retinal necrosis syndrome. METHODS: The authors performed serial clinical examinations, fundus photography, and fluorescein angiography in a patient with acquired immune deficiency syndrome with progressive outer retinal necrosis syndrome. Clinical and fluorescein angiographic findings were correlated to provide detailed sequential analysis of the pathologic changes occurring during the course of this disorder. RESULTS: The angiographic changes seen during the various stages of the disease consisted of zonal microvascular alterations, retinal pigment epithelium (RPE) destruction, and choroidal leakage. Retinal damage was correlated closely with regions of choroidal leakage and was clinically evident as outer retinal whitening. Disease reactivation occurred as a prominent brush-fire border of intense leakage involving the retina, RPE, and choroid. Extensive damage to the retinal vasculature and RPE was noted in the wake of clinical infection. CONCLUSIONS: The angiographic findings in our patient demonstrate that the progressive outer retinal necrosis syndrome is a retinochoroiditis that involves the full thickness of retina as well as the RPE and choroid. The inflammatory changes seen throughout the course of this disease correlate with the histopathologic patterns reported to date.

Combined intravenous ganciclovir and foscarnet for children with recurrent cytomegalovirus retinitis.

PURPOSE: Children with the acquired immune deficiency syndrome (AIDS) and cytomegalovirus (CMV) retinitis may not complain of symptoms despite the presence of advanced sight-threatening disease. Although little data exist regarding CMV retinitis in this population, the treatment of this disease may be difficult because of frequent, extensive recurrences after reduction of drug dose from induction to maintenance levels. The authors reported the results of the use of combined ganciclovir and foscarnet for treatment of recurrent CMV retinitis in three children with AIDS. METHODS: Three children with recurrent CMV retinitis were treated with combined ganciclovir and foscarnet administered intravenously. All patients initially received induction dosages of ganciclovir followed by maintenance therapy, at which time they experienced reactivation of their disease. The dosing regimen for induction with the combined therapy was foscarnet (60 mg/kg every 8 hours) and ganciclovir (5 mg/kg daily for 3 weeks). Maintenance with combined therapy consisted of foscarnet (90 mg/ kg daily) and ganciclovir (5 mg/kg daily). RESULTS: All patients showed complete healing of the retinitis during the first 3 weeks of combined therapy. Median survival after initiation of combined therapy was 15 weeks (range, 12-33 weeks). None of the children experienced reactivation of CMV retinitis during combined therapy with ganciclovir and foscarnet. Combined therapy was well tolerated in all patients without major side effects. No patient required discontinuation or interruption of either drug during combined therapy. CONCLUSION: Children with recurrent CMV retinitis may not report visual symptoms, which can delay therapeutic intervention. Therefore, recurrent disease in children should be treated aggressively to avoid potentially devastating visual loss. A combination of ganciclovir and foscarnet appears to be a safe and effective therapeutic option for treatment of recurrent CMV retinitis in children with AIDS. This approach causes no additional toxic reactions and may provide improved long-term control of recurrent CMV retinitis in children.

Treatment of cytomegalovirus retinitis with an intraocular sustained-release ganciclovir implant. A randomized controlled clinical trial.

BACKGROUND AND METHODS: We performed a randomized controlled clinical trial to assess the safety and efficacy of a 1 microgram/h ganciclovir implant for the treatment of newly diagnosed cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS). Patients with previously untreated peripheral CMV retinitis were randomly assigned either to immediate treatment with the ganciclovir implant or to deferred treatment. Standardized fundus photographs were taken at 2-week intervals and analyzed in a masked fashion. The study end point was progression of retinitis based on the photographic assessment. RESULTS: Twenty-six patients (30 eyes) were enrolled. The median time to progression of retinitis was 15 days in the deferred treatment group (n = 16) vs 226 days in the immediate treatment group (n = 14) (P < .00001, log-rank test). During the study, 39 primary implants and 12 exchange implants were placed in immediate-treatment eyes, deferred-treatment eyes that progressed, or contralateral eyes that developed CMV retinitis. Postoperative complications in the total series included seven late retinal detachments and one retinal tear without detachment. Final visual acuity was 20/25 or better in 34 of 39 eyes. The estimated risk of developing CMV retinitis in the fellow eye was 50% at 6 months. Biopsy-proven visceral CMV disease developed in eight (31%) of 26 patients. The median survival was 295 days. CONCLUSION: The ganciclovir implant is effective for the treatment of CMV retinitis. Patients with unilateral CMV retinitis treated with the implant are likely to develop CMV retinitis in the fellow eye, and some patients will develop visceral CMV disease.

A clinicopathologic report of the retinal lesions associated with didanosine.

Didanosine, a purine analogue with antiretroviral activity, is used in the treatment of human immunodeficiency virus disease. Associated toxic effects of didanosine include pancreatitis, peripheral neuropathy, and retinopathy. The retinal lesions associated with didanosine therapy were studied in a 6-year-old girl with acquired immunodeficiency syndrome. Gross examination disclosed multiple well-circumscribed depigmented lesions in the midperipheral retina. Microscopic examination of these lesions showed multiple areas of retinal pigment epithelial (RPE) loss, some surrounded by areas of hypertrophy or hypopigmentation of the RPE. Partial loss of the choriocapillaris and neurosensory retina were also noted in areas of diseased RPE. Transmission electron microscopy showed numerous membranous lamellar inclusions and cytoplasmic bodies in the RPE cells. These data show that didanosine primarily affects the RPE and that the choriocapillaris and overlying neurosensory retina are also dystrophic in areas of RPE loss.