Cytokine expression by invariant natural killer T cells is tightly regulated throughout development and settings of type-2 inflammation.

Invariant natural killer T (iNKT) cells produce cytokines interleukin-4 (IL-4) and IL-13 during type-2 inflammatory responses. However, the nature in which iNKT cells acquire type-2 cytokine competency and the precise contribution of iNKT cell-derived IL-4 and IL-13 in vivo remains unclear. Using IL-13-reporter mice to fate-map cytokine-expressing cells in vivo, this study reveals that thymic iNKT cells express IL-13 early during development, and this IL-13-expressing intermediate gives rise to mature iNKT1, iNKT2, and iNKT17 subsets. IL-4 and IL-13 reporter mice also reveal that effector iNKT2 cells produce IL-4 but little IL-13 in settings of type-2 inflammation. The preferential production of IL-4 over IL-13 in iNKT2 cells results in part from their reduced GATA-3 expression. In summary, this work helps integrate current models of iNKT cell development, and further establishes non-coordinate production of IL-4 and IL-13 as the predominant pattern of type-2 cytokine expression among innate cells in vivo.

Automated use of WHONET and SaTScan to detect outbreaks of Shigella spp. using antimicrobial resistance phenotypes.

Antimicrobial resistance is a priority emerging public health threat, and the ability to detect promptly outbreaks caused by resistant pathogens is critical for resistance containment and disease control efforts. We describe and evaluate the use of an electronic laboratory data system (WHONET) and a space-time permutation scan statistic for semi-automated disease outbreak detection. In collaboration with WHONET-Argentina, the national network for surveillance of antimicrobial resistance, we applied the system to the detection of local and regional outbreaks of Shigella spp. We searched for clusters on the basis of genus, species, and resistance phenotype and identified 19 statistical 'events' in a 12-month period. Of the six known outbreaks reported to the Ministry of Health, four had good or suggestive agreement with SaTScan-detected events. The most discriminating analyses were those involving resistance phenotypes. Electronic laboratory-based disease surveillance incorporating statistical cluster detection methods can enhance infectious disease outbreak detection and response.

Using internet discussion of antimicrobial susceptibility databases for continuous quality improvement of the testing and management of antimicrobial resistance.

Accurate results from the world's microbiology laboratories are essential for care of patients, control of hospital and community infections, and global epidemiology. Yet those laboratories differ greatly in their access to supplies, published literature and standards, training courses, peer interaction, and mandated quality control. Because much of what is needed is information, new information technology should help. In particular, measurements of susceptibility to antimicrobial agents, now increasingly filed in electronic databases, exhibit many kinds of variances due both to test performance and to the diversity of bacteria and of their mechanisms of resistance. In industry, workers' ongoing evaluation of variances in measurements of performance has been the basis of management programs of continuous quality improvement. Examples suggest how collegial evaluation of variances in shared susceptibility test data might similarly improve quality not only of testing but also of other aspects of the management of antimicrobial resistance. Internet access is now making such ongoing evaluation and discussion increasingly possible in most parts of the world.

The complex processes of antimicrobial resistance and the information needed to manage them.

Wide use of a succession of different manufactured antimicrobial agents during the past 60 years has prompted the eventual emergence and progressive spread through the world's interconnecting bacterial populations of a growing variety of genes expressing resistance to those agents. The complex processes that spread and link resistance genes into different distributions at different times and places are driven by antimicrobial selection and by contagion. Management of resistance by reducing selection and contagion in a coordinated way requires better information. Most of the information about the spread of resistance exists in laboratory files of isolates at medical centers, and the information about patient antimicrobial use is found in pharmacy files at the same centers. Putting these in a combined database at each center would give a valuable tool to each center's antimicrobial resistance management team. Merging such databases from multiple centers would provide a public health resource for benchmarking, overview surveillance, and general resistometrics.

Multipotent stem/progenitor cells with similar properties arise from two neurogenic regions of adult human brain.

Recent in vitro studies have shown that the periventricular subependymal zone (SEZ) of the rodent brain is capable of de novo generation of neurons and glia. There is less information available on neurogenesis in the adult human brain, and no study has shown the clonal generation of neurons and glia from in vitro-generated "neurospheres." Here we describe the isolation of proliferative stem/progenitor cells within neurospheres from two different regions, the SEZ and the hippocampus, from surgical biopsy specimens of adult (24-57 years) human brain. Using light and electron microscopy; immunocytochemistry for a variety of neuronal, glial, and developmental (including extracellular matrix; ECM) markers; and the reverse transcriptase polymerase chain reaction to demonstrate different gene transcripts found in neurospheres, it is shown that the adult human brain harbors a complex population of stem/progenitor cells that can generate neuronal and glial progeny under particular in vitro growth conditions. These methods also show that these neurospheres contain both neurons and glia and demonstrate regional similarities at the mRNA level, indicating common stem/progenitor cell types within two different neurogenic regions of the adult human brain. In addition to the synthesis of developmentally regulated molecules such as the ECM protein tenascin-C, a variety of other genes (e.g., Pax 6) and proteins (e.g. , Bcl-2) involved in cell survival and differentiation are expressed by adult human brain neurospheres.

Prophylactic hemodialysis in the treatment of acute renal failure. Annals of Internal Medicine, 53:992-1016, 1960.

Prophylactic hemodialysis has been employed in the treatment of 15 patients with acute renal failure due to acute tubular necrosis (12), bilateral renal cortical necrosis (two), and poststreptococcal glomerulonephritis (one). Dialyses, usually lasting six hours each, were begun before clinical evidence of uremia developed in each patient and/or before the nonprotein nitrogen reached 200 mg.%, and were repeated daily or often enough to maintain the nonprotein nitrogen below 150 mg.%. The hypothesis underlying this technic postulates (1) that wasting, sepsis and impaired wound healing in these patients may reflect tissue injury by the same dialyzable toxic agents which produce the uremic symptoms that are readily reversible by dialysis, and (2) that repeated dialyses should therefore prevent both clinical uremia and the later, often lethal sequelae. The results contrast dramatically with our own past experience in treating patients with acute renal failure with a carefully executed medical regimen together with hemodialysis on conventional indications. Except in one instance of crush injury with progressive intracerebral damage, and one brief occasion in another individual, these patients experienced a stable, convalescent clinical course, remained free of uremic symptoms or chemical imbalances, ate at least three meals daily which were unrestricted in amount and composition, and were ambulatory between dialyses unless confined to bed by associated disease. Wounds healed well. Infection either did not occur, or subsided after appropriate therapy. Fluid restriction was liberalized by means of ultrafiltration with dialysis. Regional heparinization of only the extracorporeal circuit eliminated actual or impending bleeding as a contraindication to dialysis. Chronic vessel cannulation made the frequent dialyses possible, but may have provided the route for repeated, transient bacterial contamination of the blood stream in the first hour of many dialyses. Marked anemia, despite reticulocytosis, moderate to mild weight loss and some mental deficit persisted in spite of the general clinical improvement and well-being. Three patients with tubular necrosis died after seven, 11 and 26 days of oliguria; both patients with bilateral renal cortical necrosis also succumbed, on the seventy-third and ninety-second days of renal failure, and after 29 and 40 dialyses, respectively. At autopsy, evidence of sepsis was conspicuously absent. The remaining 10 patients survived. Thus some, but not all, clinical manifestations of acute renal failure appear to be favorably influenced by prophylactic dialysis treatment. Our initial experience in this group of 15 patients does not of course prove that freedom from complications and a significantly better outlook for survival can be assured to patients with acute renal failure by these methods. However, it seems to offer a reasonable hope of this possibility which we cannot attach to management by medical measures alone, or by dialysis on conventional indications. If this hope is realized in greatly extended, subsequent series, then it seems inevitable that some form of prophylactic dialysis, or some equally effective alternative, should be adopted in treating the majority of patients with acute renal failure.

Encephalopathy due to capillary leak syndrome.

Systemic capillary leak syndrome (SCLS) is characterized by intermittent attacks of leakage of intravascular fluids into the extravascular space. Hypovolemia, hemoconcentration, weakness, edema, and visceral congestion are resulting manifestations of SCLS. Most patients with SCLS have clear mentation during attacks, and encephalopathy is not a known manifestation of the syndrome. We report a patient with acute idiopathic capillary leak syndrome manifested in an acute encephalopathy. The possibility of SCLS should be considered in patients who have an encephalopathy and hemoconcentration.

The global epidemic nature of antimicrobial resistance and the need to monitor and manage it locally.

An antimicrobial agent may be used for years before a gene expressing resistance to it emerges in a strain of bacteria somewhere. Progeny of that strain, or of others to which the gene is transferred, may then disseminate preferentially through global networks of bacterial populations on people or animals treated with that agent or with other agents as the gene becomes linked to genes expressing resistance to them. Over 100 resistance genes-varying in their frequency of emergence, vectors, linkages, and pathways-have thus emerged, reemerged, converged, and disseminated irregularly through the world's bacterial ecosystems over the last 60 years to reach infecting strains and block treatment of infection. We may delay emergence by using agents less and retard dissemination by good hygiene, infection control measures, and avoidance of agents that select for resistance genes in contiguous populations. Local monitoring and management of resistance appear essential because of the intricacies of tracing and targeting the problems at each place and because national or global surveillance and strategy develop from local information and understanding.

Surveillance of antimicrobial resistance: the WHONET program.

Genes expressing resistance to each antimicrobial agent emerged after each agent became widely used. More than a hundred such genes now spread selectively through global networks of populations of bacteria in humans or animals treated with those agents. Information to monitor and manage this spread exists in the susceptibility test results of tens of thousands of laboratories around the world. The comparability of those results is uncertain, however, and their storage in paper files or in computer files with diverse codes and formats has made them inaccessible for analysis. The WHONET program puts each laboratory's data into a common code and file format at that laboratory, either by serving as or by translating from its own computer reporting system. It then enables each medical center to analyze its files in ways that help it monitor and manage resistance locally and to merge them with files of other centers for collaborative national or global surveillance of resistance.

WHONET: removing obstacles to the full use of information about antimicrobial resistance.

A rich store of detailed information about antimicrobial resistance is at each medical center in paper files inaccessible to analysis or in electronic files too diverse to support a common analytical software. WHONET puts that information on a personal computer at each center in a file code and format that is the same at all centers, so that one software can then fully analyze the files at any center or those merged from many centers. The software monitors the complex matrix of interrelationships between all the measurements of resistance to antimicrobials of tested isolates of each species and of control strains. Differences at a center over time or between centers reflect differences in test performance or in the prevalence of specific resistant strains, which may be tracked. The software helps workers who are knowledgeable about resistance, infection control and clinical use of antimicrobials at any center to control test quality and integrate the management of resistance there. Their ongoing monitoring and experience locally also builds the quality and interpretation of the files merged from many centers.

Solitary focal demyelination in the brain as a paraneoplastic disorder.

Solitary focal demyelination (SFD) in the brain is an uncommon and poorly understood disorder of uncertain etiology that may represent an intermediate entity between multiple sclerosis and acute disseminated encephalomyelitis. In a few reported cases of SFD, the patient was briefly noted to have a nonneurological malignancy. We studied two patients who had solitary focal lesions in the brain. Utilizing magnetic resonance imaging and tissue biopsy, we found the characteristics of the brain lesions in these two patients to be those of SFD. In our combined experience over the past 10 years, we have encountered no similar brain lesions at our medical center. We found it remarkable that both of these patients also had malignancy outside of the nervous system. One had a seminoma, and the other a lymphoma. We conclude that some cases of SFD in the brain may occur as a paraneoplastic disorder associated with nonneurological malignancies.

Meningeal melanocytoma. An uncommon diagnostic pitfall in surgical neuropathology.

OBJECTIVE: To describe the neuropathologic findings in four cases of meningeal melanocytoma, a rare benign melanocytic tumor of the central nervous system. DESIGN: Retrospective analysis of surgical pathology and autopsy material. RESULTS: Grossly, all four tumors were well-circumscribed pigmented lesions, and three of four were attached to dura. Microscopically, the neoplasms were composed of spindle cells with epithelioid foci. Mitoses were not seen and only one case exhibited minimal necrosis. Immunohistochemistry and electron microscopy demonstrated the melanocytic nature of the lesions; all four cases showed S100 protein and neuron-specific enolase staining, and three cases exhibited melanoma-specific antigen staining. Immunostaining for epithelial markers and vimentin was uniformly negative. The single case in which electron microscopy was performed demonstrated premelanosomes. CONCLUSIONS: Meningeal melanocytoma is a benign pigmented neoplasm that can easily be confused with melanoma, especially on frozen section analysis. Practicing surgical pathologists should be aware of this entity.

DNA end labeling (TUNEL) in Huntington's disease and other neuropathological conditions.

Deoxyribonucleic acid of cells undergoing apoptosis is cleaved by a calcium-dependent endonuclease into oligonucleosomal-sized fragments. These fragments can be labeled using the enzyme terminal deoxynucleotidyl transferase so that the cells can be visualized immunohistochemically. Few investigators have evaluated this method in disease processes of the human central nervous system. The Tdt-mediated dUTP-biotin nick end labeling (TUNEL) technique has been investigated in preliminary studies of a variety of pathologic conditions of the human brain (e.g., gliomas, traumatic brain injury, Parkinson's disease, Parkinson's-Alzheimer's complex, multisystem atrophy, striatonigral degeneration). We focus, however, on Huntington's disease (HD) because of the availability of well-characterized pathological stages for study, and also because of the neurodegenerative diseases studied to date, only Huntington's disease revealed significant and consistent labeling with this method. This implies a possibly unique nature to the mechanism of cell death in Huntington's disease compared to the other neurodegenerative diseases studied. TUNEL+ neurons were found in Grade 1-4 HD neostriatum, while labeled astrocytes were found predominantly in the Grade 1 and 2 cases studied to date. TUNEL+ cells were also found in glioblastoma multiforme and traumatic brain injury. We conclude that while there appear to be several limitations associated with this technique, it may be useful for identifying both apoptosis and necrosis in certain neuropathological conditions.

Hemangioblastoma of the radial nerve: case report.

A case of hemangioblastoma of the right radial nerve is presented. Hemangioblastomas are rare vascular neoplasms characteristically associated with the Von Hippel-Lindau syndrome, in which they are found in the retina, the posterior fossa, and, less often, the spinal cord. Thought of as primary central nervous system neoplasms, hemangioblastomas are rarely found adjacent to the spinal cord involving proximal nerve roots, which represent border zones between the central and peripheral nervous systems. We could find no other report of a pure hemangioblastoma situated this far distally in the peripheral nervous system. The histological findings, immunohistochemistry, and electron microscopic findings of this lesion are discussed. This case supports the hypothesis that hemangioblastoma is not derived from astrocytes, because of the location of this tumor in the peripheral nervous system and glial fibrillary acidic protein negativity.

Focal brain injury and upregulation of a developmentally regulated extracellular matrix protein.

Tenascin is an extracellular matrix glycoprotein expressed during both normal development and neoplastic growth in both neural and nonneural tissues. During development of the central nervous system (CNS), tenascin is synthesized by glial cells, in particular by immature astrocytes, and is concentrated in transient boundaries around emerging groups of functionally distinct neurons. In the mature CNS, only low levels of the glycoprotein can be detected. The present study demonstrates that following trauma to the adult human cerebral cortex, discrete populations of reactive astrocytes upregulate their expression of tenascin and dramatically increase their transcription of the tenascin gene. The enhanced expression of tenascin may be involved in CNS wound healing, and may also affect neurite growth within and around a brain lesion.

Detection and surveillance of antimicrobial resistance.

The clinical microbiology laboratory is strategically positioned to recognize changing patterns in bacterial resistance to antimicrobials. This requires the application of accurate testing methods and a methodological survey of drug-resistance patterns among clinically important bacteria. This information can be assembled into comprehensive international databases, using a common format to facilitate monitoring.

Neuron-glial interactions during the in vivo and in vitro development of the nigrostriatal circuit.

This paper examines a particular aspect of glial-neuronal interactions during central nervous system development: the possible influence of growing neurites on the expression of glial-associated extracellular matrix (ECM) molecules. In particular, using in vivo manipulations of the dopaminergic projections from the midbrain substantia nigra, as well as an in vitro model of the developing nigrostriatal circuit, we look at the reciprocal interactions between growing dopaminergic axons and astrocyte-derived ECM molecules in the striatum. Glial-derived glycoconjugates, including tenascin and a proteoglycan designated DSD-1, are developmentally expressed ECM molecules which have been shown to have different effects on immature neurons and their growing processes. Here we show that the glial expression of these ECM constituents in a target region (the caudate-putamen or neostriatum) may be affected by the presence or absence of an appropriate, maturing afferent projection (in this case, dopaminergic nigrostriatal axons). In general, our results reveal complex glial-neuronal interactions during the normal development of central nervous system circuits, and the ability to create in vivo and in vitro models which may be useful toward understanding these complex cellular and molecular interactions in degeneration and plasticity of the nigrostriatal circuit in diseases including Parkinson's.