A conceptual model of emergency department crowding.

Emergency department (ED) crowding has become a major barrier to receiving timely emergency care in the United States. Despite widespread recognition of the problem, the research and policy agendas needed to understand and address ED crowding are just beginning to unfold. We present a conceptual model of ED crowding to help researchers, administrators, and policymakers understand its causes and develop potential solutions.

CXCL10 production from cytomegalovirus-stimulated microglia is regulated by both human and viral interleukin-10.

Glial cells orchestrate immunocyte recruitment to focal areas of viral infection within the brain and synchronize immune cell functions through a regulated network of cytokines and chemokines. Since recruitment of T lymphocytes plays a critical role in resolving cytomegalovirus (CMV) infection, we investigated the production of a T-cell chemoattractant, CXCL10 (gamma interferon-inducible protein 10) in response to viral infection of human glial cells. Infection with CMV was found to elicit the production of CXCL10 from primary microglial cells but not from astrocytes.

Pulmonary microvascular fracture in a patient with acute respiratory distress syndrome.

Objective: To present electron micrographs of lung tissue obtained from a patient exposed to high ventilatory pressures in the context of pulmonary dysfunction and pulmonary hypertension.

Design: Case report.

Setting: Adult intensive care unit of a university-affiliated teaching hospital.

Why do treated hypertensives suffer strokes? An internist's perspective.

Despite widespread treatment of hypertension, stroke continues to be the third leading cause of death in the United States. Antihypertensive therapy is more effective in preventing hemorrhagic strokes than ischemic strokes. In order to understand the reasons why antihypertensive therapy is only partially successful in the eradication of ischemic strokes, differences in the pathogenesis and treatment of subtypes of stroke must be considered.

Understanding and Managing Isolated Systolic Hypertension in the Elderly.

In summary, ISHT in the elderly is a result of the interaction of increased systemic vascular resistance and of progressive arterial stiffening. The early return of reflected pulse wave may add to peak SBP in the ascending aorta and central arteries, thereby increasing LV systolic stress (afterload). Antihypertensive therapy has been shown to be effective in the prevention of strokes associated with ISHT.

Directional tuning profiles of motor cortical cells.

The directional tuning profiles of motor cortical cells are commonly described by a cosine tuning function with three adjustable parameters (Georgopoulos, A.P., Kalaska.

Apoptosis, Bcl-2, and proliferating cell nuclear antigen in the failing human heart: observations made after implantation of left ventricular assist device.

Background: Heart failure is characterized by progressive left ventricular remodeling, a complex process that results from cell growth and cell death. The quantitative contribution of apoptotic cells toward left ventricular remodeling has varied widely in tissue removed from cardiomyopathic hearts. Apoptosis has been responsive to angiotensin-converting enzyme inhibition in experimental heart failure, but the dynamics and responsiveness to chronic left ventricular unloading have not been studied.

Killing of Streptococcus pneumoniae by capsular polysaccharide-specific polymeric IgA, complement, and phagocytes.

The role of IgA in the control of invasive mucosal pathogens such as Streptococcus pneumoniae is poorly understood. We demonstrate that human pneumococcal capsular polysaccharide-specific IgA initiated dose-dependent killing of S. pneumoniae with complement and phagocytes.

Relationship between hypercholesterolaemia, endothelial dysfunction and hypertension.

Objectives: We have previously shown that in the rat a diet high in cholesterol and deficient in vitamin E and selenium results in hypercholesterolaemia and increased lipid oxidation. We utilized this model to determine whether rats given this diet develop impaired endothelium-dependent relaxation mediated by nitric oxide (NO) in mesenteric and in renal vessels. In addition, we tested whether the impairment is due to (i) decreased endothelial NO synthase activity, (ii) increased NO inactivation and/or (iii) increased production of the endothelium-derived constricting factors thromboxane A2/prostaglandin H2 and endothelin-1.

Fas ligand expression in the bone marrow in myelodysplastic syndromes correlates with FAB subtype and anemia, and predicts survival.

Increased apoptosis in the bone marrow (BM) may contribute to the cytopenias that occur in myelodysplastic syndromes (MDS). The Fas receptor, Fas ligand (FasL) pathway is a major mechanism of apoptosis. Since hematopoietic progenitors can express the Fas receptor, they may be susceptible to apoptosis induced by FasL-expressing cells.

Analysis of polysomnographic events surrounding 252 slow-wave sleep arousals in thirty-eight adults with injurious sleepwalking and sleep terrors.

A systematic study of electrophysiologic events [eight-channel EEG, electrocardiogram, electromyogram (EMGs)] surrounding 252 arousals from slow-wave sleep (SWS) in adults with sleepwalking (SW) and sleep terrors (ST) is reported. Hospital-based, overnight polysomnographic monitoring was conducted in 38 adults presenting to a sleep disorders center with injurious SW, ST (21 males, 17 females; mean age 29 years, range 17-69 years). Before nonbehavioral or behavioral arousals from SWS, neither EEG "delta wave buildup," nor heart rate (HR) acceleration, nor tonic/phasic EMG activation was identified.

Nitric oxide synthase activity and renal injury in genetic hypertension.

Nitric oxide (NO) is an endogenous vasodilator synthesized in the endothelium by constitutive NO synthase (cNOS). We have shown that upregulation of cNOS activity in hypertension may contribute to forestalling left ventricular and aortic hypertrophy (Hypertension. 29: 235, 1997).

Nitric oxide in hypertension: relationship with renal injury and left ventricular hypertrophy.

Hypertension is accompanied by architectural changes in the kidney, heart, and vessels that are often maladaptive and can eventually contribute to end-organ disease such as renal failure, heart failure, and coronary disease. Nitric oxide, an endogenous vasodilator and antithrombotic agent synthesized in the endothelium by a constitutive nitric oxide synthase, inhibits growth-related responses to injury in vascular cells. Specifically, in the presence of hypertension, nitric oxide may work in the kidney by inhibiting both mesangial cell hypertrophy and hyperplasia as well as synthesis of extracellular matrix and in the heart and systemic vessels by modulating smooth muscle cell hypertrophy and hyperplasia.

Fecal hydrogen sulfide production in ulcerative colitis.

Objective: Sulfide, a product of sulfate-reducing bacteria, has been proposed to play an etiologic role in ulcerative colitis. Ulcerative colitis feces have increased numbers and activity of sulfate-reducing bacteria, but only modestly increased sulfide. However, fecal sulfide exists largely in the volatile, highly toxic H2S form that moves rapidly from feces to surrounding gas.

Cryptococcal glucuronoxylomannan induces interleukin (IL)-8 production by human microglia but inhibits neutrophil migration toward IL-8.

On the basis of the clinical observation that the cerebrospinal fluid (CSF) of patients with cryptococcal meningitis contains high levels of the chemokine interleukin (IL)-8 but few polymorphonuclear leukocytes (PMNL), the production of IL-8 by cultured brain glial cells after stimulation with two serotypes of cryptococcal capsular polysaccharide glucuronoxylomannan (GXM) was studied, followed by an assessment of the effect of GXM on PMNL migration toward IL-8. GXM serotype A but not D was capable of inducing IL-8 production in human fetal microglial cell but not in astrocyte cultures. When added directly to the PMNL, GXM (both serotypes) potently blocked PMNL migration toward IL-8.

Endothelial dysfunction and cardiorenal injury in experimental salt-sensitive hypertension: effects of antihypertensive therapy.

Background: Pharmacological control of hypertension has contributed to a significant decrease in cardiovascular morbidity and mortality, although the beneficial effect on cardiac and renal diseases has been far more modest than the reduction in stroke. The endothelium plays a crucial homeostatic role in the regulation of vascular tone thrombogenesis and vascular remodeling. We studied the relationship between endothelial dysfunction and cardiorenal injury in hypertensive rats and evaluated the effects of two classes of antihypertensive agents commonly used in the clinical setting, a diuretic (DIU) and an ACE inhibitor (CEI).

Mental rotation studied by functional magnetic resonance imaging at high field (4 tesla): performance and cortical activation.

We studied the performance and cortical activation patterns during a mental rotation task (Shepard & Metzler, 1971) using functional magnetic resonance imaging (fMlU) at high field (4 Tesla). Twenty-four human subjects were imaged (fMRI group), whereas six additional subjects performed the task without being imaged (control group). All subjects were shown pairs of perspective drawings of 31, objects and asked to judge whether they were the same or mirror images.

Differential production of and migratory response to beta chemokines by human microglia and astrocytes.

Little is known about the participation of beta chemokines in inflammatory processes within the central nervous system. The release of three of these peptides (macrophage inflammatory protein [MIP]-1alpha, MIP-1beta, and monocyte chemoattractant protein-1) from human fetal microglial cell and astrocyte cultures was assessed following stimulation by lipopolysaccharide, interleukin-1beta, and tumor necrosis factor-alpha. Although striking differences were found between these two types of glial cells in their responsiveness to lipopolysaccharide and cytokines, both microglia and astrocytes produced all three beta chemokines.

Chronic viral hepatitis enhances the risk of infection but not acute rejection in renal transplant recipients.

To assess the impact of chronic viral hepatitis on host immune response, we analyzed the incidence of acute rejection and the frequency of infections in 86 patients infected with hepatitis B and C viruses and had developed clinical evidence of chronic liver disease and 1283 control patients who were transplanted at our center during the same period, but had no evidence of chronic viral hepatitis. To compare the mean number of rejections and the mean number of infections between the two groups, we used multivariate linear regression analysis, which allowed us to adjust simultaneously for the effects of 10 other risk variables with potential impact on graft rejection and posttransplant infection. During a mean follow up of 5.

kappa opioid receptors in human microglia downregulate human immunodeficiency virus 1 expression.

Microglial cells, the resident macrophages of the brain, play an important role in the neuropathogenesis of human immunodeficiency virus type 1 (HIV-1), and recent studies suggest that opioid peptides regulate the function of macrophages from somatic tissues. We report herein the presence of kappa opioid receptors (KORs) in human fetal microglia and inhibition of HIV-1 expression in acutely infected microglial cell cultures treated with KOR ligands. Using reverse transcriptase-polymerase chain reaction and sequencing analyses, we found that mRNA for the KOR was constitutively expressed in microglia and determined that the nucleotide sequence of the open reading frame was identical to that of the human brain KOR gene.