A clinical and biological review of keratoacanthoma.

Keratoacanthoma (KA) is a common skin tumour that remains controversial regarding classification, epidemiology, diagnosis, prognosis and management. Classically, a KA manifests as a rapidly growing, well-differentiated, squamoid lesion with a predilection for sun-exposed sites in elderly people and a tendency to spontaneously regress. Historically, KAs have been considered a variant of cutaneous squamous cell carcinoma (cSCC) and are often reported as KA-type cSCC. However, the penchant for regression has led many to categorize KAs as biologically benign tumours with distinct pathophysiological mechanisms from malignant cSCC. The clinical and histopathological similarities between KA and cSCC, particularly the well-differentiated variant of cSCC, have made definitive differentiation difficult or impossible in many cases. The ambiguity between entities has led to the general recommendation for surgical excision of KAs to ensure a potentially malignant cSCC is not left untreated. This current standard creates unnecessary surgical morbidity and financial strain for patients, especially the at-risk elderly population. There have been no reports of death from a definitive KA to date, while cSCC has an approximate mortality rate of 1·5%. Reliably distinguishing cSCC from KA would shift management strategies for KAs towards less-invasive treatment modalities, prevent unnecessary surgical morbidity, and likely reduce associated healthcare costs. Herein, we review the pathophysiology and clinical characteristics of KA, and conclude on the balance of current evidence that KA is a benign lesion and distinct from cSCC.

Impact of Home-Delivered Meals on Nutrition Status and Nutrient Intake among Older Adults in Central Texas.

OBJECTIVE: This study aimed to measure changes in nutrition risk and nutrient intake after older adults received home-delivered meals (HDM) for 3 months. DESIGN: This study used a pre-posttest study design, with data collected before and after 3 months of HDM services. SETTING: Two HDM programs that serve the metropolitan areas of Austin and San Antonio, Texas. PARTICIPANTS: Study participants were aged 60 years or older, without dementia or terminal illness, and receiving HDM in Austin, Texas and San Antonio, Texas for 3 months. MEASUREMENTS: The Nutrition Screening Initiative (NSI) and Mini Nutrition Assessment-Short Form (MNA-SF) were used to assess nutritional risk. The National Cancer Institute Diet History Questionnaire II (DHQ II) was used to assess nutrient intake over the past month. RESULTS: After receiving 3 months of HDM, nutrition status significantly improved as measured by the NSI and MNA-SF. More participants met or exceeded the recommended dietary allowances (RDA) for magnesium and zinc after receiving HDM compared to before receiving HDM. Dietary supplement intake was associated with a higher nutritional risk. CONCLUSION: Improvements in nutrition status were found after 3 months of receiving HDM, whereas intake of most nutrients did not change significantly. Results of this study provide further evidence that HDM can reduce nutritional risk of older adults, and may inform HDM programs on the differences of NSI and/or MNA-SF to assess nutritional risk of clients.

Comparison of Food Intake Among Infants and Toddlers Participating in a South Central Texas WIC Program Reveals Some Improvements After WIC Package Changes.

In 2009, WIC began issuing revised food packages with the intent of improving dietary practices such as breastfeeding, delaying the introduction of complementary foods until about 6 months, limiting juice intake, and increasing intake of fruits, vegetables, whole grains, and baby food meats as appropriate for age. This observational study investigated whether dietary intake and feeding practices of a sample of majority-Hispanic infants and toddlers participating in a WIC clinic in south central Texas improved after the package changes. Feeding practices data and 24-h recalls were collected during telephone interviews with 84 caregivers of infants (4-12 months) and toddlers (1-2 years) in 2009 before the package change and with 112 caregivers in 2011 after the package change. The Nutrition Data System for Research was used to collect 24-h recalls. Outcomes for the two study years were compared using Chi square analysis for categorical and Mann-Whitney U analysis for continuous variables. Breastfeeding initiation, breastfeeding duration, age of introduction of complementary foods, and exposures to baby food fruits, vegetables, and meats among infants did not improve after the package changes. Significantly fewer infants received cereal in their bottles and fewer toddlers consumed vegetables and eggs after the package changes. The observed feeding practices of infants and toddlers among this sample did not reflect the WIC package changes. Strategic and comprehensive breastfeeding and nutrition education are recommended. Package modifications such as adding eggs back to the toddler package and allowing more flexibility for purchasing fresh produce and baby foods may be warranted.

Effects of the Clarion Electrode Positioning System on auditory thresholds and comfortable loudness levels in pediatric patients with cochlear implants.

OBJECTIVE: To evaluate the effects of using the Electrode Positioning System on psychophysical auditory thresholds, most comfortable loudness levels, and electric auditory brainstem response (EABR) thresholds in children with the Clarion version 1.2 cochlear implant. DESIGN: Retrospective analysis. SETTING: Academic tertiary care center. PATIENTS AND METHODS: Clinical records of a series of 25 children who received the Clarion version 1.2 cochlear implant at the University of Minnesota, Minneapolis, between January 1997 and August 1999 were examined. Measures evaluated were psychophysical thresholds (T-levels) and most comfortable loudness levels (M-levels) obtained at the 3-month posthookup audiologic evaluation and EABR thresholds obtained during implant surgery. Relevant threshold measures were available for 24 patients, 11 of whom had received the Clarion spiral electrode and electrode positioner (EP group) and 13 of whom had received the spiral electrode without positioner (non-EP group). The 3 measures (T-levels, M-levels, and EABR thresholds) were compared across groups. In addition, EABR thresholds were compared with T-levels and M-levels within groups. RESULTS: Mean T-levels and M-levels were significantly lower for the EP group than for the non-EP group, and interpatient variability for these measures was considerably smaller in the EP group. Electric auditory brainstem response thresholds were not significantly different for EP vs non-EP patients; however, EABR data were available for only a few non-EP patients. CONCLUSIONS: Use of the electrode positioner results in lower T-levels and M-levels in children with the Clarion version 1.2 cochlear implant, consistent with results of previous studies in adults, and reduces across-patient variability for these measures. It is unclear from the present data whether use of the electrode positioner systematically reduces intraoperative EABR thresholds.

Acute hemodynamic and coronary circulatory effects of experimental autoimmune myocarditis.

Myocarditis and progression to cardiomyopathy is associated with focal spasm and reperfusion of the coronary microcirculation. Experimental autoimmune myocarditis (EAM), induced with cardiomyosin peptide-specific T cells in Lewis rats, was hypothesized to cause acute hemodynamic and coronary vasculature changes. Fifteen experimental animals (5 each at 1, 2, and 3 weeks after T-cell injection) and eight controls were studied using the constant pressure variant of the isolated heart. Coronary resistant decreased while coronary flow increased (P < 0.05) in EAM hearts after the first week. Rate-pressure product, +dP/dt and -dP/dt, decreased while the heart/body weight ratio increased (P < 0.05) compared with controls at 1 week but not at 2 or 3 weeks. Mean local myocardial PO2, which reflects local oxygen delivery and consumption, and MVO2 were not different for EAM hearts. However, compared with controls EAM myocardial PO2 varied more widely and was often beyond the usual range, suggesting the occurrence of localized hypoxic and hyperoxic areas. In summary, after the first week there was a significant decrease in coronary resistance in the EAM animals, which required higher flow to maintain a similar perfusion pressure. These changes in coronary resistance and flow along with the heterogeneity and extremes of local myocardial PO2 levels without a significant change in MVO2 may be explained by postulating development of low-resistance, high-flow hyperoxic areas which steal flow, thus causing hypoxia in other areas.

Myocardial oxygen tension in isolated erythrocyte-perfused rat hearts and comparison with crystalloid media.

The isolated heart, typically perfused with crystalloid media equilibrated with >/=95% O2 to ensure adequate myocardial oxygen tension, is commonly used to study cardiac function. When hemoglobin is available for oxygen transport, equilibration with 21% O2 is considered adequate to meet metabolic demands. This study presents the measurement of myocardial pO2 in isolated hearts perfused with an erythrocyte suspension. Baseline myocardial pO2 in erythrocyte-perfused hearts was 16.4+/-3.5 mmHg (mean+/-s.e.). When compared to previous measurements of myocardial pO2 in isolated hearts perfused with crystalloid media, the use of erythrocyte suspensions resulted in a 10-fold lower level of myocardial pO2, while avoiding very low and high values. The standard use of 95% oxygen with crystalloid results in myocardial levels of oxygen far above those usually found in the presence of hemoglobin and room air.

Myocardial oxygen tension and capillary density in the isolated perfused rat heart during pharmacological intervention.

Oxygen is essential for normal cardiac function and plays an important role in cardiac regulation. Electron paramagnetic resonance (EPR) oximetry appears to have some significant advantages for measuring oxygen tension (pO2) in the beating heart. This study presents the serial measurement of myocardial pO2 by EPR oximetry in the isolated crystalloid perfused heart during treatment with different cardioactive drugs: dobutamine, metoprolol, verapamil, vasopressin, and N omega-Nitro-L-Arginine Methyl Ester (L-NAME). Baseline myocardial pO2 was 176 +/- 14 mmHg (mean +/- S.E.). Myocardial capillary density in the intact contracting heart was calculated to be 2300 +/- 100 mm-2, using local myocardial pO2 and a cylindrical model for oxygen diffusion in tissue. Each drug had characteristic effects on myocardial pO2, myocardial oxygen consumption (MVO2), and capillary density. Metoprolol and verapamil increased myocardial pO2 by 51% and 18%, respectively, dobutamine decreased myocardial pO2 by 84% while vasopressin and L-NAME had no significant effect on myocardial pO2. Metoprolol and verpamil decreased MVO2 by 9% and 56%, respectively, while dobutamine increased MVO2 by 59%. A quantitative comparison of effects on the capillary bed based on changes in myocardial pO2 and MVO2 was made. Metoprolol and verapamil had opposite effects on the capillary bed. Verapamil decreased myocardial capillary density by 39%, while capillary density increased by 10% (n.s.) with metoprolol. Data following perfusion without drug is also presented. We conclude that: 1) The application of EPR oximetry with LiPc provides dynamic evaluation of local myocardial pO2 in the contracting heart. 2) Using a cylindrical model of oxygen delivery and diffusion in tissue, these data may be used to describe the changes of capillary density during pharmacological interventions.

Effect of repetitive ischemia on myocardial oxygen tension in isolated perfused and hypoperfused rat hearts.

The objective of this study was to determine the effects of repetitive ischemia on myocardial oxygen tension (pO2), consumption, and delivery in crystalloid normoperfused (perfusion pressure>70 mmHg) and hypoperfused (perfusion pressure approximately 50 mmHg) constant flow isolated rat hearts. EPR oximetry with lithium phthalocyanine was used to measure myocardial pO2. Baseline myocardial pO2 (means +/- SE) was 185 +/- 13 mmHg (normoperfused) and 162 +/- 14 mmHg (hypoperfused). Myocardial pO2 fell to < 1 mmHg during no-flow ischemia. After recovery from repetitive ischemia, myocardial pO2 and coronary resistance increased significantly in all hearts; oxygen consumption and left ventricle work decreased in normoperfused hearts, although not significantly compared with controls, and did not change significantly in hypoperfused hearts. Increased myocardial pO2 in the normoperfused group may be due to decreased oxygen consumption and/or increased local delivery, while increased myocardial pO2 in the hypoperfused hearts is due to increased local oxygen delivery.

Myocardial oxygen tension and relative capillary density in isolated perfused rat hearts.

Oxygen plays an important role in cardiac function. Many methods have been applied to measure tissue oxygen tension (PO2). Electron paramagnetic resonance (EPR) oximetry appears to have some significant advantages for use in the beating heart. This study presents the serial measurement of myocardial PO2 by EPR oximetry in the isolated crystalloid perfused heart during changes of influent PO2, coronary flow rate, oxygen consumption and end-diastolic pressure. Baseline myocardial PO2 was 198 +/- 12 mmHg (mean +/- S.E.). Myocardial PO2 increased as expected with increased delivery (concentration or flow) or decreased consumption. With increasing flow rate, myocardial PO2 increased in a sigmoid fashion. A critical flow or pressure was reached when myocardial PO2 rapidly increased to a higher level. Increased left ventricular end-diastolic pressure caused local vascular compression and resulted in a decrease of myocardial PO2. Myocardial capillary density in the intact contracting heart was calculated to be 2300 +/- 110/mm2, using local myocardial PO2 and a cylindrical model for oxygen diffusion in tissue. Relative capillary density did not change with mild to moderate hypoxia, increased with increasing flow and increasing oxygen consumption and decreased with elevated diastolic pressure. We conclude that the application of EPR oximetry with LiPc to the isolated heart provides accurate and dynamic evaluation of local myocardial PO2 in the contracting heart. Using various models of oxygen delivery and diffusion in tissue, these data may also be used to serially follow capillary density.

Double-lumen catheter assessment of aortic stenosis: comparison with separate catheter technique.

Hemodynamic assessment of aortic stenosis in the catheterization laboratory accurate determination of the transvalvular gradient. A commercially available double-lumen pigtail catheter can be used to obtain this gradient via a single arterial puncture. The catheter has several advantages over other methods used to measure the gradient in aortic stenosis, but it has not been critically evaluated. In order to assess the performance of this catheter compared to the traditional standard of separate catheters above and across the aortic valve, we studied 10 patients with aortic stenosis using both catheter systems. Aortic valve areas ranged from 0.34 cm2 to 1.1 cm2. Linear regression analysis confirmed excellent correlation between the two methods in measurement of the mean transvalvular gradient (r = 0.98) and calculation of the aortic valve area (r = 0.99) using the Gorlin formula. We conclude that the double-lumen pigtail catheter provides accurate data in the hemodynamic evaluation of aortic stenosis.

Hospital smoking policies: who enforces them?

As opprobrium is increasingly given to the act of smoking, many institutions--hospitals especially--are seeking to curtail the amount of smoking that occurs within their buildings through various policies. This, however, raises two necessary questions: What does policy enforcement mean? And who shall enforce the rules? The article below discusses the results of a survey of North Carolina hospitals that asked these questions and more.