Subacute (acute,persistent) thrombotic microangiopathy

Six patients with prolonged acute courses of thrombotic microangiopathy are reviewed. These patients had in common courses of acute disease requiring plasma support for more than 3 months, with subsequent complete remission. Plasma support requirements may be prodigious, and the acute course may require more than 100 plasma exchanges before a stable remission is achieved. These patients appear to represent a subset of thrombotic microangiopathy distinct from the more common acute T.T.P. course, which resolves in 3–6 weeks, and the chronic relapsing pattern, which may have a short or prolonged acute course. © 1992 Wiley-Liss, Inc.     

Analysis of resistance to gas flow in nine adult ventilator circuits

We measured the resistance in nine complete ventilator circuits, partial circuits and 7, 8, and 9 mm ID endotracheal tubes at flow rates of 20 to 120 liters per minute. We found a statistically significant (p less than 0.01) increase in resistive pressure with increases in flow rate, as the diameter of the ETT decreased, and as each component of the ventilator circuit was added to the ETT. There was a curvilinear increase in resistive pressure to increase in flow rate. However, when resistances were computed, the Bennett cascade "circuit" created higher resistance at 20 lpm than at flow rates up to 120 lpm. The Bennett cascade humidifier added the greatest resistive pressure, 3.5 to 8.5 cm H2O, the Engstrom Edith, 0.5 to 6.5 cm H2O, and the Conchapak added the least, 0.0 to 2.5 cm H2O at flow rates of 20 to 120 lpm. After all the components of the ventilator circuit were attached to the ETTs, there was approximately a 97 to 450 percent increase in resistive pressure compared to the resistive pressure created by the ETTs alone.     

Solubility properties in polymers and biological media. 2. The correlation and prediction of the solubilities of nonelectrolytes in biological tissues and fluids

Solubilities of a range of nonelectrolyte solutes in biological systems, such as blood, plasma, brain, lung, liver, kidney, muscle tissue, and human fat, are correlated and predicted through an equation that takes the form log Ltissue = c + w log Lwater + o log Loil, where L is the Ostwald solubility coefficient (or gas/liquid partition coefficient). The ratio of the constants o and w gives a measure of the "oiliness" of a given biological tissue or fluid. The strong possibility exists that, for many types of nonelectrolyte solutes, simple measurements of solubilities in water and oil (gas/liquid partition coefficients) will allow accurate predictions of solubilities in the above biological solvents, as well as tissue/blood partition coefficients. The solubility of rare gases and the inorganic gases H2, N2, CO, and O2 may be correlated through the simpler equation log Ltissue = l'RG + d', where l' and d' are constants that characterize the phase, and RG is a known parameter, obtained by normalizing and averaging solubilities over a range of solvent systems, that characterizes the solute. Both of the above equations allow prediction of L in biological solvents to within about 20%, which compares well with the precision of the experimental measurements.     

Fulcrum for the future: the creation of a values-driven culture

This article describes the efforts of a small children's specialty hospital to prepare for a difficult period of restructuring in the marketplace by using the organization's core values as a force for direction, stabilization, and leverage. A best practices model was used to identify values that were a central part of the hospital's cultural heritage but were also critical for ensuring future institutional success. Principles for values definition and implementation provide guidance for other health care institutions.     

Adenine nucleotide levels in preserved and ischemically injured canine kidneys

This study explored the relationship between adenine nucleotide levels in canine renal cortex and renal function following: (a) graded periods of warm ischemia; (b) 48 hours' flush cooling with electrolyte solutions and ice storage; and (c) continuous hypothermic perfusion. Exposure to normothermic ischemia resulted in a rapid (within 15 minutes) degradation of ATP to ADP and AMP as well as a slow decline in total adenine nucleotide (TAN) to levels which were proportional to the duration of the ischemic injury. No functional impairment was evident after 15 minutes' ischemia, but with longer times, both the extent of decline in TAN and the degree of recovery following restoration of blood flow could be used to predict the quality of renal function.The relationship between TAN levels and function was of less predictive value following cold storage or continuous perfusion. The efficacy of intracellular flush solutions could not be attributed solely to conservation of TAN, nor did the well-maintained TAN levels during continuous perfusion necessarily lead to significantly better 48-hour storage than flush cooling with C2 solution.

---

Résumé Cette étude faite chez le chien examine la corrélation entre la fonction rénale et le taux d'adénine nucléotide dans le cortex rénal suite à: 1) différentes périodes d'ischémic chaude; 2) entreposage sur glace pendant 48 heures apres flushing avec des solutions électrolytiques; 3) hypotermie par perfusion continuelle. L'ischémie chaude a produit une dégradation rapide de l'ATD en ADP et AMP (en moins de 15 minutes) et une diminution progressive de la quantité totale d'adénine nucléotide (TAN) proportioneile à la durée de la période ischémique. La fonction rénale n'a pas été affectée par des périodes d'ischémie de 15 minutes ou moins. Suite à des périodes ischémiques plus longues cependant, la chutte des taux de TAN et leur niveau de rétablissement après réouverture de la circulation sanguine ont permis de prédire la qualité de la fonction rénale. Après storage au froid ou perfusion continue, la relation entre les taux de TAN et la fonction rénale est disparue. Le flushing à l'aide des solutions de type intracellulaire, malgré sa faible capacité à conserver les taux de TAN s'est avéré une méthode d'entreposage aussi efficace que la perfusion continuelle, laquelle a maintenu des taux normaux de TAN.

---

---

Supported by Veterans Administration Research Grant 1519-01.     

Effects of morning versus evening administration of atorvastatin in patients with hyperlipidemia.

PURPOSE: The effects of morning versus evening administration of atorvastatin in hyperlipidemic patients were studied. METHODS: Patients whose care was managed by a teaching hospital run by the Department of Veterans Affairs who were prescribed atorvastatin calcium 40 mg p.o. daily by their primary care physician were interviewed by a clinical pharmacist in the ambulatory care clinic for study enrollment. Patients were excluded if they had diseases or conditions or took medication known to affect serum lipoprotein levels, as were patients who consumed more than three alcoholic drinks per day and those who could not verify the time of atorvastatin administration. Blood samples were collected after a 12-hour fasting period and serum lipoprotein levels were measured at baseline and after four weeks. RESULTS: Of the 204 hyperlipidemic patients receiving atorvastatin, 64 met the inclusion criteria and were enrolled in the study, 32 of whom took the drug in the morning (before noon) and an equal number who took the drug at night (after 6 p.m. but before midnight). All patients were male outpatients with a mean +/- S.D. age of 57.8 +/- 7.8 years and 58.5 +/- 7.8 years for the morning and evening administration groups, respectively. No statistically significant differences in lipid values measured were found between the morning and evening administration group after four weeks. CONCLUSION: Changes in the levels of total cholesterol, low-density-lipoprotein cholesterol, triglycerides, and high-density-lipoprotein cholesterol were similar among hyperlipidemic patients receiving atorvastatin calcium 40 mg, regardless of the time of day the drug was administered.     

The impact of chemokine receptor CX3CR1 deficiency during respiratory infections with Mycobacterium tuberculosis or Francisella tularensis

Recruitment of immune cells to infection sites is a critical component of the host response to pathogens. This process is facilitated partly through interactions of chemokines with cognate receptors. Here, we examine the importance of fractalkine (CX3CL1) receptor, CX3CR1, which regulates function and trafficking of macrophages and dendritic cells, in the host''s ability to control respiratory infections with Mycobacterium tuberculosis or Francisella tularensis. Following low-dose aerosol challenge with M. tuberculosis, CX3CR1^−/− mice were no more susceptible to infection than wild-type C57BL/6 mice as measured by organ burden and survival time. Similarly, following inhalation of F. tularensis, CX3CR1^−/− mice displayed similar organ burdens to wild-type mice. CX3CR1^−/− mice had increased recruitment of monocytes and neutrophils in the lung; however, this did not result in increased abundance of infected monocytes or neutrophils. We conclude that CX3CR1-deficiency affects immune-cell recruitment; however, loss of CX3CR1 alone does not render the host more susceptible to M. tuberculosis or F. tularensis.