Retinal nerve fiber layer thickness remains unchanged following laser-assisted in situ keratomileusis.

PURPOSE: To evaluate the effect of laser-assisted in situ keratomileusis (LASIK) on retinal nerve fiber layer (RNFL) thickness measurements obtained with scanning laser polarimetry (SLP), optical coherence tomography (OCT), and scanning laser tomography (SLT). DESIGN: Interventional case series. METHODS: Twenty eyes (20 patients) undergoing LASIK were enrolled in this prospective study. SLP, OCT, and SLT examinations were performed 1 week prior to and 1 week and 4 weeks after LASIK surgery. Intraocular pressure was normal at all preoperative and postoperative examinations. SLP, OCT, and SLT mean RNFL thickness values, and SLT RNFL cross sectional area, rim area, and rim volume before and after LASIK were compared by the Student paired t test. RESULTS: Mean patient age was 39.3 +/- 9.5 (SD) years (range, 28 to 62 years). Mean preoperative spherical equivalent refractive error was -3.9 +/- 1.9 diopters (D) (range, -1.4 to -8.00 D) and mean spherical equivalent refractive surgical correction was 3.6 +/- 1.9 D (range, 1.00 to 8.50 D). Mean RNFL thicknesses obtained by SLP were thinner 1 week and 4 weeks after LASIK (P < 0.01, for all comparisons, paired t test), whereas mean OCT RNFL thickness and SLT RNFL thickness, RNFL cross-section area, rim area, and rim volume measurements were unchanged 1 week and 4 weeks after LASIK (P > or = 0.05, for all comparisons, paired t test). CONCLUSIONS: LASIK does not affect RNFL thickness. Alterations in SLP RNFL thickness measurements are due to alterations in corneal architecture rather than an actual LASIK-induced RNFL injury.

Trials, lies, and options.

AIDS: A case study is presented of a 47-year-old HIV infected man. The patient's clinical findings are presented. He has joined two clinical trials since his diagnosis, but on the first one he did not adhere to the regimen, and on the second one, he admits that he probably will not adhere to the regimen. Dr. Bruce Soloway and Dr. Meg Newman present their point of views on this case. The patient's relationship with his primary care provider is discussed, as are the underlying emotional issues that may contribute to his reluctance to adhere to possible treatments. The benefits and risks of delaying antiretroviral therapy are also discussed.^ieng

Report on the Sixth Conference on Retroviruses and Opportunistic Infections.

AIDS: The Sixth Conference on Retroviruses and Opportunistic Infections has provided HIV research with exciting advances in understanding the mechanisms of HIV disease and treatment. However, few answers were found to important clinical questions, such as when to begin antiretroviral therapy. The most important presentations are summarized and grouped by major issues. Advances in combination therapy were discussed, including new information on the effectiveness of PI-sparing antiretroviral combinations and the promising results seen with ABT-378, a "second generation" PI. Research was also presented on the decline of opportunistic infections since the advent of HAART, the increased focus on metabolic consequences, and the importance of adherence. Further study is required to find solutions for patients failing HAART and to make treatment available to those who need it.^ieng

Report on the Fifth Conference on Retroviruses and Opportunistic Infections.

AIDS: Presentations made at the Fifth Conference on Retroviruses and Opportunistic Infections are summarized. Hundreds of papers confirmed and analyzed the impact of highly active antiretroviral therapy (HAART) in clinical trials and routine clinical care. Papers on HAART therapy and research on the underlying dynamics of HIV infection are highlighted in the areas of epidemiology, prevention, HIV pathophysiology, primary HIV infection, combination antiretroviral therapy, salvage therapy, antiretroviral toxicities, adherence issues, and opportunistic infections. The papers show that the theoretical and therapeutic advances made in 1996 and 1997 are tempered by challenges that remain: the emergence of viral resistance, extensive cross resistance affecting antiretrovirals still in the development pipeline, the failure to extend the benefits of antiretroviral therapy to the vast majority of AIDS patients, the continuing problem of HIV transmission, and the need and frustrating search for a vaccine.^ieng

Primary care and specialty care in the age of HAART.

AIDS: The advent of complex highly active antiretroviral therapy (HAART) brings to light the issue of whether people with HIV infection or AIDS should be managed by a primary care physician or by an HIV specialist. There is no HIV specialist per se, however, experience can increase the skills needed to treat this disease. Experience is defined as having treated between 5 and 20 patients living with HIV. Primary care physicians have historically developed skills in treating chronic multisystem diseases, but HIV has gained a new complexity with the battery of antiretroviral medications available. Primary care physicians must now learn about viral dynamics and resistance, viral load measurements, and the specifics of each available drug. In addition, educating patients to comply with their regimens requires counseling skills, knowledge of adverse effects management, and managing lifestyle issues. Consulting with experienced practitioners on various aspects of HIV infection and AIDS is useful and the network of medical consultants should always be strengthened. All patients deserve to be treated by a physician with current skills in providing antiretroviral therapy, as well as by a committed primary care physician.^ieng

Managed care and HIV.

AIDS: In order to control costs, a transition from fee-for-service plans to managed care for people with HIV infections and AIDS is developing in the United States. The question arises whether a cost-conscious, competitive environment can deliver quality care to people with a disease that is complex and expensive to treat. Several options can be used to keep managed care from removing incentives for treating too many HIV and AIDS patients. Approaches include increasing capitation fees for patients who require more resources, and utilizing a carve-out approach from the State-managed Medicaid plans to separate HIV from the mainstream plans. However, rate determination under either option is problematic and may entail analyzing the cost of care under the fee-for-service system as a benchmark, including cost variations at various stages of HIV disease. This analysis also includes developing accurate adjustments for changes in treatment and assessing the quality of care that is received. Quality of care can be assessed through an analysis of outcomes, processes, and structures of care.^ieng

Molecular symmetry of fructose-1,6-diphosphatase by X-ray diffraction analysis.

Large single crystals of rabbit liver fructose-1,6-diphosphatase suitable for a high resolution structure analysis have been grown from polyethylene glycol. The space group of these crystals is I222 with a = 75 A, b = 81 A, and c = 132 A and there are 2 tetrameric molecules in the unit cell. These crystals have one protein subunit as the crystallographic asymmetric unit and establish point group symmetry 222 as the molecular symmetry.

Alkylamine salts and amides: in vitro inhibition of S mutans 6715.

Our studies with the salts and amides of alkylamines have shown that the undecylenate salts have significant in vitro activity against S mutans No 6715, suggesting that these agents are worthy of additional evaluation. The attempt to increase activity by combining undecylenic acid with the alkylamines was not successful; however, better attachment to tooth surfaces and/or retention during washing did occur. Our results suggest that the free amino group of alkylamines and the free acid group of undecylenic acid are required for these two classes of agents to demonstrate antibacterial activity.

Prolongation of antibacterial activity of chlorhexidine adsorbed to teeth. Effect of sulfates.

The results suggest that the effectiveness of sulfates in prolonging the antibacterial activity of teeth treated with chlorhexidine gluconate is related to the acidity and concentration of the sulfate solutions. The acidity may contribute to the effectiveness by modifying the tooth surface for enhanced reaction with sulfate ions. It is suggested that during the priming process bonded crystals of calcium sulfate develop which become transformed by treatment with chlorhexidine gluconate to relatively insoluble chlorhexidine sulfate.

Synthesis and in vitro evaluation of 8-hydroxyquinoline analogs as inhibitors of dental plaque.

A group of 5-substituted 8-hydroxyquinolines with predicted log P values in the 1-4 range has been prepared from either 8-hydroxyquinoline or its appropriate derivative. 5-Formyl-, 5-iodo-, 5-fluoro-, 5-acetyl-, and 5-methoxymethyl-8-hydroxyquinoline in addition to methyl-5(8-hydroxyquinolyl)acetate and ethyl 5-(8-hydroxyquinolyl)acetate displayed greater in vitro antiplaque activity than 8-hydroxyquinoline.

A physiochemical approach to the study of amines as antiplaque agents.

Alkyl and aromatic amines were evaluated for inhibitory activity against S mutans 6715. Only the alkylamines were active and this may be due to their greater basicity. The agents that showed good activity were decylamine, dodecylamine, tetradecylamine, and hexadecylamine. In addition to the free bases, the hydrochloride and hydrofluoride salts were also tested for inhibitory activity and the same four agents were shown to be most active. These agents appear to hold good promise as antiplaque agents against S mutans 6715, therefore, further in vitro studies against other plaque-forming bacteria and toxicological and clinical evaluation seems to be warranted to determine the best clinical agent.

Synthesis and in vitro evaluation of 8-hydroxyquinolines as dental plaque inhibitors.

Some 4- and 5-substituted 8-hydroxyquinolines, with predicted log P values in the range of 1.48-2.90, were synthesized by modified Skraup reactions or thermal cyclization. These hydroxyquinolines include the 5-methyl, 4,5-dimethyl, 4-methyl, 5-hydroxy-4-methyl, 5-methoxy, 5-methoxy-4-methyl, 4-hydroxy, 4-chloro, 4-amino, and 5-amino analogs. Partition coefficients, antibacterial activity, and antiplaque activity were determined. Four analogs showed in vitro antiplaque activity. None of the derivatives with ionizable functions was active.