Should Physician-Assisted Suicide or Euthanasia be Legalized in the United States? A Medically Informed Perspective.

There is a pressing debate in the United States concerning the implied physicians' obligation to do no harm and the status of legalizing physician-assisted suicide (PAS). Key issues that underpin the debate are important to consider. These include: (1) foundational medical beginnings; (2) euthanasia's historical and legal background context; and (3) the key arguments held by those for and against legalization of PAS. This paper reviews the major claims made by proponents for the legalization of PAS and the associated complexities and concerns that help underscore the importance of conscience freedoms. Relief of suffering, respect for patient autonomy, and public policy arguments are discussed in these contexts. We argue here that the emphasis by healthcare providers should be on high quality and compassionate care for those at the end of life's journey who are questioning whether to prematurely end their lives. If medicine loses its chief focus on the quality of caring-even when a cure is not possible-it betrays its objective and purpose. In this backdrop, legalization of PAS harms not only healthcare professionals, but also the medical profession's mission itself. Medicine's foundation is grounded in the concept of never intentionally to inflict harm. Inflicting death by any means is not professional or proper, and is not trustworthy medicine.

Practical Guidance for Clinical Microbiology Laboratories: Diagnosis of Ocular Infections.

The variety and complexity of ocular infections have increased significantly in the last decade since the publication of Cumitech 13B, Laboratory Diagnosis of Ocular Infections (L. D. Gray, P. H. Gilligan, and W. C. Fowler, Cumitech 13B, Laboratory Diagnosis of Ocular Infections, 2010). The purpose of this practical guidance document is to review, for individuals working in clinical microbiology laboratories, current tools used in the laboratory diagnosis of ocular infections. This document begins by describing the complex, delicate anatomy of the eye, which often leads to limitations in specimen quantity, requiring a close working bond between laboratorians and ophthalmologists to ensure high-quality diagnostic care. Descriptions are provided of common ocular infections in developed nations and neglected ocular infections seen in developing nations. Subsequently, preanalytic, analytic, and postanalytic aspects of laboratory diagnosis and antimicrobial susceptibility testing are explored in depth.

Ultrastructural analysis of the human lens fiber cell remodeling zone and the initiation of cellular compaction.

The purpose is to determine the nature of the cellular rearrangements occurring through the remodeling zone (RZ) in human donor lenses, identified previously by confocal microscopy to be about 100 µm from the capsule. Human donor lenses were fixed with 10% formalin followed by 4% paraformaldehyde prior to processing for transmission electron microscopy. Of 27 fixed lenses, ages 22, 55 and 92 years were examined in detail. Overview electron micrographs confirmed the loss of cellular organization present in the outer cortex (80 µm thick) as the cells transitioned into the RZ. The transition occurred within a few cell layers and fiber cells in the RZ completely lost their classical hexagonal cross-sectional appearance. Cell interfaces became unusually interdigitated and irregular even though the radial cell columns were retained. Gap junctions appeared to be unaffected. After the RZ (40 µm thick), the cells were still irregular but more recognizable as fiber cells with typical interdigitations and the appearance of undulating membranes. Cell thickness was irregular after the RZ with some cells compacted, while others were not, up to the zone of full compaction in the adult nucleus. Similar dramatic cellular changes were observed within the RZ for each lens regardless of age. Because the cytoskeleton controls cell shape, dramatic cellular rearrangements that occur in the RZ most likely are due to alterations in the associations of crystallins to the lens-specific cytoskeletal beaded intermediate filaments. It is also likely that cytoskeletal attachments to membranes are altered to allow undulating membranes to develop.

Dematiaceous fungi mimicking a conjunctival melanoma.

An 85-year-old, immunocompetent man was referred to the authors due to the presence of an enlarging, pigmented mass of the conjunctiva concerning for a conjunctival melanoma. Wide excision of the mass revealed a pigmented or "dematiaceous" fungus. He was treated with topical natamycin, and the lesion healed well without any evidence of recurrence. Dematiaceous fungi should be considered in the differential for pigmented conjunctival lesions.

Keratouveitis from Euphorbia cyparissias exposure is a temporal phenomenon.

We present the case of an 82-year-old woman with severe keratouveitis secondary to exposure to the plant Euphorbia cyparissias during the month of August. Despite copious irrigation of both eyes, she developed a case of Euphorbia keratouveitis that was typical in its course. Exposure to plant sap from this species should be treated much like an alkaline chemical injury as the pH of the ocular surface may be elevated. E. cyparissias should be carefully handled as it may result in keratouveitis, especially in early autumn.

Electron tomography of fiber cell cytoplasm and dense cores of multilamellar bodies from human age-related nuclear cataracts.

Human nuclear cataract formation is a multi-factorial disease with contributions to light scattering from many cellular sources that change their scattering properties over decades. The aging process produces aggregation of cytoplasmic crystallin proteins, which alters the protein packing and texture of the cytoplasm. Previous studies of the cytoplasmic texture quantified increases in density fluctuations in protein packing and theoretically predicted the corresponding scattering. Multilamellar bodies (MLBs) are large particles with a core of crystallin cytoplasm that have been suggested to be major sources of scattering in human nuclei. The core has been shown to condense over time such that the refractive index increases compared to the adjacent aged and textured cytoplasm. Electron tomography is used here to visualize the 3D arrangement of protein aggregates in aged and cataractous lens nuclear cytoplasm compared to the dense protein packing in the cores of MLBs. Thin sections, 70 nm thick, were prepared from epoxy-embedded human transparent donor lenses and nuclear cataracts. Tilt series were collected on an FEI T20 transmission electron microscope (TEM) operated at 200 kV using 15 nm gold particles as fiducial markers. Images were aligned and corrected with FEI software and reconstructed with IMOD and other software packages to produce animated tilt series and stereo anaglyphs. The 3D views of protein density showed the relatively uniform packing of proteins in aged transparent lens nuclear cytoplasm and less dense packing of aged cataractous cytoplasm where many low-density regions can be appreciated in the absence of the TEM projection artifacts. In contrast the cores of the MLBs showed a dense packing of protein with minimal density fluctuations. These observations support the conclusion that, during the nuclear cataract formation, alterations in protein packing are extensive and can result in pronounced density fluctuations. Aging causes the MLB cores to become increasingly different in their protein packing from the adjacent cytoplasm. These results support the hypothesis that the MLBs increase their scattering with age and nuclear cataract formation.

Mycobacterium chelonae canaliculitis associated with SmartPlug use.

Mycobacterium chelonae is ubiquitous in the environment but is an uncommon cause of ocular and periocular infections. It is a pathogen that has been gaining increased attention in the ophthalmic literature because of the relatively large number of infections associated with laser-assisted in situ keratomileusis and other forms of refractive surgery. The authors present 3 patients who developed canaliculitis culture positive for M. chelonae more than a year after SmartPlug placement. These cases highlight some of the clinical scenarios that may be encountered in those who present with canaliculitis with a history of intracanalicular plug placement. Therapeutic considerations are also suggested.

Predicted light scattering from particles observed in human age-related nuclear cataracts using mie scattering theory.

PURPOSE: To employ Mie scattering theory to predict the light-scattering from micrometer-sized particles surrounded by lipid shells, called multilamellar bodies (MLBs), reported in human age-related nuclear cataracts. METHODS: Mie scattering theory is applicable to randomly distributed spherical and globular particles separated by distances much greater than the wavelength of incident light. With an assumed refractive index of 1.40 for nuclear cytoplasm, particle refractive indices from 1.33 to 1.58 were used to calculate scattering efficiencies for particle radii 0.05 to 3 microm and incident light with wavelengths (in vacuo) of 400, 550, and 700 nm. RESULTS: Surface plots of scattering efficiency versus particle radius and refractive index were calculated for coated spherical particles. Pronounced peaks and valleys identified combinations of particle parameters that produce high and low scattering efficiencies. Small particles (<0.3 microm radius) had low scattering efficiency over a wide range of particle refractive indices. Particles with radii 0.6 to 3 microm and refractive indices 0.08 to 0.10 greater (or less) than the surrounding cytoplasm had very high scattering efficiencies. This size range corresponds well to MLBs in cataractous nuclei (average MLB radius, 1.4 microm) and, at an estimated 4000 particles/mm(3) of tissue, up to 18% of the incident light was scattered primarily within a 20 degrees forward cone. CONCLUSIONS: The calculated size of spherical particles that scatter efficiently was close to the observed dimensions of MLBs in cataractous nuclei. Particle refractive indices only 0.02 units different from the surrounding cytoplasm scatter a significant amount of light. These results suggest that the MLBs observed in human age-related nuclear cataracts may be major sources of forward light scattering that reduces contrast of fine details, particularly under dim light.

A new paradigm for corneal wound healing research: the white leghorn chicken (Gallus gallus domesticus).

PURPOSE: To evaluate the chicken cornea as a model for corneal wound healing research. METHODS: We conducted studies on normal chicken corneas and on corneas following mechanical debridement and photorefractive keratectomy (PRK). RESULTS: The chicken cornea possesses six distinct layers that resemble the layers of the human cornea, including a substantial Bowman's layer measuring 5.2 +/- 0.3 microm thick. Reepithelialization time was 44.8 +/- 1.1 hours with a sliding rate of 75.3 +/- 3.2 microm/hour following mechanical debridement and 54.4 +/- 2.8 hours with a sliding rate of 63.3 +/- 3.2 microm/hour for PRK-treated corneas. Biomicroscopic haze post-PRK peaked at 4-6 weeks and regressed until 20 weeks post-PRK. Histologic and clinical observations of wound healing strongly paralleled that noted in humans. CONCLUSION: The chicken cornea's morphology and wound healing response render it a useful model for corneal wound healing investigations.