Eligible Veterans'' Choice Between VA-covered and Non-VA-covered Dental Care

Veterans who were eligible for dental care in Department of Veterans Affairs (VA) facilities at no monetary cost responded to a mailed questionnaire. Seventy-one percent were aware that they were actually eligible for VA dental care. However, only 48 percent reported the VA as their only or primary source of dental care. Eligibility status, perceived quality of VA dental care, use of VA medical care, perception that one's income meets expenses, and perceived need for dental care were significant correlates of using the VA as one's current source of dental care. Level of formal education, perception that one's income meets expenses, transportation pattern, geographic distance from a VA facility, and eligibility status were significant correlates of using the VA as one's current medical care source. Research on VA utilization offers the opportunity to study issues of access to, and use of, a large public health care system whose patients largely receive care at no monetary cost. Veterans' use of VA dental and medical care is apparently influenced by a wide variety of factors, ranging from barriers to access to non-VA systems, to characteristics of the VA delivery system itself, to need for treatment.     

Human liver microsomal N-hydroxylation of dapsone by cytochrome P-4503A4.

One of the major routes of elimination of dapsone (4,4'-diaminodiphenylsulfone) is by N-oxidation, to produce a hydroxylamine metabolite. The specific form of cytochrome P-450 (P-450) involved in this oxidation reaction was examined in human liver microsomal preparations previously characterized with respect to their content of several known P-450 enzymes. Among five preparations, the rank order of activity for dapsone hydroxylamine formation was most well correlated with the immunochemically determined level of P-4503A4 (r = 0.94, p less than 0.03). Moreover, inhibition of microsomal oxidation was observed with antibodies specific to P-4503A, with a maximum reduction of greater than 90%, but was not produced by antibodies specific to P-4501A2, P-4502CMP, or P-4502E1. Prior incubation of microsomes with gestodene (100 microM) or troleandomycin (20 microM), known selective mechanism-based inhibitors of P-4503A enzymes (in the presence of NADPH), led to 75% and 40% reductions in catalytic activity, respectively. In contrast, preincubation with increasing concentrations of alpha-naphthoflavone, a known activator of P-4503A4, increased dapsone N-hydroxylation in a concentration-dependent manner, with 5-fold activation being observed at 50 microM alpha-naphthoflavone. Finally, P-4503A4 isolated from human liver microsomes and cDNA-expressed P-4503A4 (in yeast) were both able to catalyze dapsone N-hydroxylation, with the latter preparation exhibiting a 3-fold activation in the presence of 100 microM alpha-naphthoflavone. Collectively, these findings demonstrate that N-oxidation of dapsone in human liver is predominantly mediated by P-4503A4, and they suggest that quantitative measurement of this metabolic pathway in vivo might serve as an index of the activity of this enzyme.     

The emergency physician and patient confidentiality: A review

Confidentiality is a promise rooted in tradition, law andmedical ethics. Emergency physicians treat a variety of patients to whom confidentiality is of vital importance: employees, celebrities, victims of violence or disaster, minors, students, criminals, drug abusers, and patients with STDs. EDs should develop methods of ensuring confidentiality for all patients.³⁴Although confidentiality is an important principle thatshould be respected and guarded, it is not absolute. Various laws mandate disclosure of certain patient information; in addition, an overriding moral duty may occasionally require, a breach of confidentiality. As Beauchamp and Childress noted, “the therapeutic role may sometimes have to yield to ones role as citizen and as protector of the interests of others”.¹⁹ In general, however, circumstances requiring a breach of confidentiality are rare.     

Cine CT for attenuation correction in cardiac PET/CT.

In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we evaluated the use of cine CT, which acquires multiple low-dose CT images during a respiratory cycle. We evaluated the average and the intensity-maximum image of cine CT for cardiac PET attenuation correction. METHODS: Cine CT data and cardiac PET data were acquired from a cardiac phantom and from multiple patient studies. The conventional helical CT, cine CT, and PET data of an axially translating phantom were evaluated with and without respiratory motion. For the patient studies, we acquired 2 cine CT studies for each PET acquisition in a rest-stress (13)N-ammonia protocol. Three readers visually evaluated the alignment of 74 attenuation image sets versus the corresponding emission image and determined whether the alignment provided acceptable or unacceptable attenuation-corrected PET images. RESULTS: In the phantom study, the attenuation correction from helical CT caused a major artifactual defect in the lateral wall on the PET image. The attenuation correction from the average and from the intensity-maximum cine CT images reduced the defect by 20% and 60%, respectively. In the patient studies, 77% of the cases using the average of the cine CT images had acceptable alignment and 88% of the cases using the intensity maximum of the cine CT images had acceptable alignment. CONCLUSION: Cine CT offers an alternative to helical CT for compensating for respiratory motion in the attenuation correction of cardiac PET studies. Phantom studies suggest that the average and the intensity maximum of the cine CT images can reduce potential respiration-induced misalignment errors in attenuation correction. Patient studies reveal that cine CT provides acceptable alignment in most cases and suggest that the intensity-maximum cine image offers a more robust alternative to the average cine image.