Cross-tissue immune cell analysis reveals tissue-specific features in humans.

Despite their crucial role in health and disease, our knowledge of immune cells within human tissues remains limited. We surveyed the immune compartment of 16 tissues from 12 adult donors by single-cell RNA sequencing and VDJ sequencing generating a dataset of ~360,000 cells. To systematically resolve immune cell heterogeneity across tissues, we developed CellTypist, a machine learning tool for rapid and precise cell type annotation. Using this approach, combined with detailed curation, we determined the tissue distribution of finely phenotyped immune cell types, revealing hitherto unappreciated tissue-specific features and clonal architecture of T and B cells. Our multitissue approach lays the foundation for identifying highly resolved immune cell types by leveraging a common reference dataset, tissue-integrated expression analysis, and antigen receptor sequencing.

Cooperative regulation of AJM-1 controls junctional integrity in Caenorhabditis elegans epithelia.

The function of epithelial cell sheets depends on the integrity of specialized cell-cell junctions that connect neighbouring cells. We have characterized the novel coiled-coil protein AJM-1, which localizes to an apical junctional domain of Caenorhabditis elegans epithelia basal to the HMR-HMP (cadherin-catenin) complex. In the absence of AJM-1, the integrity of this domain is compromised. Proper AJM-1 localization requires LET-413 and DLG-1, homologues of the Drosophila tumour suppressors Scribble and Discs large, respectively. DLG-1 physically interacts with AJM-1 and is required for its normal apical distribution, and LET-413 mediates the rapid accumulation of both DLG-1 and AJM-1 in the apical domain. In the absence of both dlg-1 and let-413 function AJM-1 is almost completely lost from apical junctions in embryos, whereas HMP-1 (alpha-catenin) localization is only mildly affected. We conclude that LET-413 and DLG-1 cooperatively control AJM-1 localization and that AJM-1 controls the integrity of a distinct apical junctional domain in C. elegans.

alpha IIb beta 3 redistribution triggered by receptor cross-linking.

Fibrinogen binding to alpha IIb beta 3 on adherent, spread platelets triggers active, cytoskeletally-directed redistribution of fibrinogen/alpha IIb beta 3 complexes on the platelet surface. Gold-conjugated fibrinogen, unlabeled, soluble fibrinogen, and individual fibrinogen molecules have been demonstrated to trigger receptor redistribution. Here we examine the respective roles of receptor cross-linking and ligand occupancy of receptors in initiating this movement. Monovalent, alpha IIb beta 3-binding fibrinogen fragments RGDS and HHLGGAKQAGDV did not trigger receptor redistribution, suggesting that ligand binding to a single receptor is an insufficient stimulus. Binding of monoclonal antibodies 10E5, AP2, and AP3 to the receptor did not trigger receptor movement. However, cross-linking these receptor-bound monoclonal antibodies by polyclonal anti-mouse IgG or by conjugation of the anti-receptor antibody to large colloidal gold particles triggered receptor redistribution identical in rate, pattern, and final distribution to that previously seen with fibrinogen binding. We conclude that receptor cross-linking provides the signal for initiation of fibrinogen/alpha IIb beta 3 complex redistribution on platelet surfaces.

Hearing metaphor: an approach to working with family-generated metaphor.

This article presents a step-by-step approach to working with family-generated metaphor in family therapy. Although the use of therapist-generated "therapeutic metaphors" has been widely advocated and practiced for many years now, less attention has been paid to the metaphors used by family members. We argue that the family's metaphors are a neglected linguistic resource in family therapy. Highlighting and validating these metaphors produces a therapeutic conversation in which the voices of family members are heard more clearly by the therapist, and the families' own imaginative energies are engaged in defining and pursuing the goals of therapy. Several case examples illustrate the use of this approach with children of various ages.

Three-dimensional extracellular matrix textured biomaterials.

Clinical and experimental investigations have reported that manufactured surface topographies have significant effects on cell adhesion and tissue integration. However, essentially all previously examined topographies bear little relation to cell adhesion substrates found in biological tissues. In vivo, many cells are adherent to extracellular matrices (ECM), which have an extremely complex 3-D topography in the micrometre to nanometre range. In addition, many studies indicate that micro- and nano-scale mechanical stresses generated by cell-matrix adhesion have significant effects on cellular phenotypic behaviour. In this report we describe methodology for the fabrication of topographic replicas of the subendothelial ECM topography with a biomedical polyurethane. Using three-dimensional high resolution scanning electron microscopy, accurate replication of subendothelial ECM topography from the macroscopic to the macromolecular scale is demonstrated. Bovine aortic endothelial cells cultured on the ECM replicas spread more rapidly and had a three-dimensional appearance and spread areas at confluence which appeared more like endothelial cells in native arteries, compared with cells cultured on untextured control surfaces. Since the fabrication process may be used with many different types of materials, including polymers of synthetic and biological origin, these biomimetic ECM-textured surfaces may find both research and clinical applications.

Ischemia/reperfusion injury of the ascending colon in ponies: a correlative study utilizing microvascular histopathology and corrosion casting.

Volvulus of the ascending colon (ACV) in the horse results in microvascular injury and necrosis of the intestinal mucosa. This study investigated the site and type of microvascular injury which occurs within the mucosa and submucosa following ACV. Histopathology of volvulus treated ponies demonstrated mucosal necrosis with microvascular hemorrhage and thrombosis. Thrombi occurred within the subepithelial capillaries and edema and hemorrhage developed throughout the mucosa and submucosa. Vascular casts allowed 3-D viewing of samples obtained from the entire pelvic flexure and demonstrated two distinct microvascular changes: 1) disruption of the colonic glandular capillary network occurred concomitantly with the mucosal injury, and 2) extensive endothelial leakage from the submucosal microvasculature contributes to edema formation. Thus, microcorrosion casting of the equine pelvic flexure provided an effective means to characterize the location and severity of vascular leakage and visualize the extent and severity of injury to the capillary network not easily depicted by histopathology. Microvascular casting in conjunction with routine histopathology provided additional information on the pathomorphologic changes in this model of ischemia/reperfusion injury.

Improved tissue corrosion of vascular casts: a quantitative filtration method used to compare tissue corrosion in various concentrations of sodium and potassium hydroxide.

In this study, we compare weights of filter retained material (11 microns particle retention) after solubilization and filtration of unfixed, un-perfused tissue (fat, liver and trachea) in sodium and potassium hydroxide (1%, 5%, 10% and 20% weight/volume, w/v) at 8, 24 and 48 hour time points at 45 degrees C. Three detergents [1% Triton-X-100 (volume/volume, v/v), 1% 7X (v/v), 1% Terg-A-Zyme (w/v)] used in combination with hydroxide were evaluated for use in solubilizing fat. Additionally, vascular casts from mouse kidneys were corroded to test the practical effectiveness of corroding solutions on resin infused tissue. Five percent KOH for eight hours proved to be the most effective concentration and time required to corrode fatty tissue. Liver tissue was corroded most rapidly in 1% to 5% NaOH or in 1% to 20% KOH. Corrosion of trachea tissue showed that 5, 10 and 20% hydroxide (NaOH or KOH) are equally effective after 8 hours of corrosion. Use of detergents improved solubilization of fat when combined with 2%, 3% or 5% NaOH. However, fatty tissue was solubilized more rapidly without the use of detergents in 1% NaOH. Scanning electron microscopy of vascular casts shows that corrosion in 1% NaOH appears equally as effective as corrosion in 15% KOH.

An asbestos hazard in North Devon.

In March 1990, following the careless removal of asbestos-based ceiling tiles in a leisure centre in North Devon, delay in action by the local authority meant that the risk to staff and members of the public was ignored for four months. The Director of Public Health was then approached to tackle the problem of providing advice to both leisure centre staff and the public in order to deal with the concern that had arisen as a result of the delay. There was a public statement, a report to the local authority, and a 'hotline' for members of the public. Leisure centre staff members were individually interviewed by a doctor using a specially designed occupational health questionnaire and followed up as appropriate. Twenty-one chest X-rays were taken on the advice of the local chest physician. Although the level of exposure was small, and there was no significant threat to health, the incident caused major public concern, was an embarrassment to the local authority, and involved the Health and Safety Executive and considerable input from the Department of Public Health Medicine. Most importantly for a small district, it was a major public relations exercise for Public Health Medicine. This paper examines the appropriateness and effectiveness of intervention by Public Health Medicine in a situation where the risks were known to be very low but public anxiety, fuelled by compensation possibilities, was very high.

Diabetes mellitus as a risk factor for stroke.

To evaluate the relative potency of diabetes mellitus as a risk factor for stroke, the relative frequency of stroke symptoms was compared among cohorts with and without diabetes. Stroke symptoms were classified as atherothrombotic cerebral infarctions, transient ischemic attacks, reversible ischemic neurologic deficits, and multi-infarct dementia. The groups were compared according to the occurrence of these symptoms, and both cross-sectional and longitudinal designs were used to study 293 consecutive patients referred to this laboratory and to contrast groups with and without diabetes. Hypertension, heart disease, and stroke symptoms and signs were more frequent among diabetics than among age-matched nondiabetics. Among diabetics, strokes occurred at an earlier age and were more common among men. Regression analyses assigned diabetes second to hypertension as a risk factor for stroke, followed by heart disease and smoking. Diabetes associated with hypertension or hyperlipidemia added significantly to stroke risk. Initially, cerebral blood flow values and cognitive test scores were equivalent among diabetics and nondiabetics; after 3 years, cognition became significantly impaired among diabetics, despite better maintenance of cerebral blood flow among treated diabetics compared with nondiabetics. Diabetes acts to compound risk for stroke not only by promoting cerebral atherogenesis but also by aggravating other risk factors including hypertension, heart disease, and hyperlipidemia.

Neuropathological and neuropsychological changes in Alzheimer's disease. Relationship of biologic markers to behavioral markers.

Alzheimer's disease is the fourth most common cause of death in the United States, and is the leading cause of functional disability in the elderly. This article analyzes the pathologic validity of mental status tests and the biochemistry of Alzheimer's disease patients.

The general practitioner in the inner city: a survey of a London health district.

A survey of general practitioners in Tower Hamlets health district in London is reported. The findings indicate a caring and concerned group of doctors who are working under considerable difficulty. The pattern of general practice in this district is dissimilar to the rest of the country, with infrequent use of attached staff, poor accommodation, more single-handed practices, and a predominance of elderly doctors trained overseas and either approaching or beyond conventional retirement age. Some suggestions are made towards the future development of the family doctor service.