The MAIA (Methanogenic Activity and Inhibition Analyser) is a titration (pH-stat) biosensor designed to determine the activity and inhibition related to acetoclastic methanogens. The main operational problems encountered in using this instrument are described.

Bioreactors↗

PubMed2001

CD antigens 2001.

This paper reviews the Seventh Human Leucocyte Differentiation Antigen (HLDA7) workshop. Due to the limitations of "blind" antibody screening, which had been evident at the previous meeting in 1996, participants at HLDA7 adopted a more selective approach to the choice of antibodies by identifying new CD specificities. This resulted in the addition of more than 80 new CD specificities. Plans for the eighth and subsequent workshops are also previewed.

Antibodies, Monoclonal↗

PubMed2000

Illumination for coherent soft X-ray applications: the new X1A beamline at the NSLS.

The X1A soft X-ray undulator beamline at the NSLS has been rebuilt to serve two microscopy stations operating simultaneously. Separate spherical-grating monochromators provide the resolving power required for XANES spectroscopy at the C, N and O absorption edges. The exit slits are fixed and define the coherent source for the experiments. The optical design and the operational performance are described.

Journal Article↗

PubMed2000

Dermatomal pruritus precipitated by drinking excessive quantities of black tea.

Explore the source record for details and available documents.

Drinking↗

PubMed2000

Nativity and older women's health: constructed reliance in the health and retirement study.

Gender and nativity are known risk factors for physical and economic dependency. Immigrant women are particularly disadvantaged because of their greater lack of social and economic resources. In this study, we investigate how women immigrants coordinate and utilize various support systems as they approach retirement age, as well as how choices and constraints affect their physical wellbeing. Experiences throughout the life course play a role in the maintenance of health, but the pre-retirement years are particularly crucial to the establishment of patterns of reliance to be used in later life. We examine the effects of economic resources, social support, and family ties (as well as several exogenous variables) on women's physical health using data from the Health and Retirement Survey. For the women in this study, demographic characteristics, such as Hispanic ethnicity and low education are strong risk factors for poor health. Findings also indicate that reliance patterns across resource domains do not differ significantly by nativity and that both economic and familial resource access significantly lessens the risk of poor health for both native and foreign born women.

Aged↗

PubMed2000

High cell density provides potent survival signals for resting T-cells.

Activated T-cells are susceptible to apoptosis through two particularly important pathways: ligation of CD95 (Fas/Apo-1) or cytokine deprivation. Resting T-cells have until recently been considered to be relatively resistant to apoptosis. In this report we show that resting T-cells die rapidly by apoptosis when deprived of serum or cell contact. Primed CD45RO+ cells were more susceptible than naive CD45RA+ cells, consistent with their relative expression of Bcl-2. CD4+, CD8+ and gammadelta T-cells were equally prone to apoptosis under all studied conditions. A linear relationship between cell survival and serum concentration was observed for cells cultured between 0.5-2x10(6)/ml. T-cells cultured at low density died even in high concentrations of serum. However, resting T-cells cultured at high cell density (4x10(6)/ml) survived for extended periods in the absence of serum or other survival factors. This effect was mediated by the production of soluble factors and independent of integrin mediated signals. These results suggest that T-cells at sites of high density such as the lymph node paracortex are independent of external survival factors, while those trafficking through the peripheral circulation are highly dependent on serum derived factors for survival.

Apoptosis↗

PubMed1999

Localized bowel vasculitis: postoperative cyclophosphamide or not?

We describe 2 patients with necrotizing vasculitis localized to the bowel, who were treated by excision of the involved tissue. Postoperatively, there was no evidence of active vasculitis, and both patients remain in remission on followup, without the use of immunosuppressive treatment. Evidence that an abnormal local microenvironment is necessary to sustain chronic inflammation may explain why surgical excision can be an important tool in the treatment of vasculitis.

Adult↗

PubMed1999

Cerebral proton and phosphorus-31 magnetic resonance spectroscopy in patients with subclinical hepatic encephalopathy.

BACKGROUND/AIMS: In vivo magnetic resonance spectroscopy can be used to study cerebral metabolism non-invasively. We aimed to correlate 1H and 31P magnetic resonance spectral abnormalities in the brains of patients with subclinical hepatic encephalopathy. METHODS: Eighteen patients were studied at 1.5T, with combined 1H and 31P magnetic resonance spectra obtained from multiple voxels in the cerebral cortex and basal ganglia. Peak area ratios of choline, glutamine/glutamate, relative to creatine in the 1H spectra and percentage phosphomonoesters, phosphodiesters and betaNTP signals relative to total 31P signals in the 31P spectra were measured. RESULTS: Six patients did not complete the full examination - 31P results are available from 12 patients only. Relative to creatine, there were reductions in choline and elevations in glutamine/glutamate, varying across the brain with choline significantly reduced in occipital cortex (p<0.05) and glutamine/glutamate most significantly elevated in temporo-parietal cortex (p<0.0001). Percentage phosphomonoester (p<0.05), phosphodiester (p<0.05) and betaNTP (p<0.005) signals were significantly decreased in basal ganglia spectra. No correlation was found between the magnitude of 1H and 31P MRS changes, except between percentage phosphodiester decrease and glutamine/glutamate to creatine increase in occipital cortex. CONCLUSION: The results of this study point to a multifactorial aetiology for this condition.

Adult↗

PubMed1999

An MRI study of the effect of treadmill training on bone morphology of the central and third tarsal bones of young thoroughbred horses.

Training results in marked modelling of the subchondral bone of the carpus, but the effect of training on the subchondral bone of the distal tarsal joints is unknown. The aim of this study was to determine whether training influenced modelling of the third and central tarsal bones in Thoroughbred horses. Twelve untrained Thoroughbred horses were divided into 2 groups. Group 1 underwent a 19 week progressive training regimen on a high speed treadmill. Group 2 were walked for 40 min daily. Images of left tarsi were obtained by magnetic resonance imaging (MRI) with a 0.5 Tesla superconducting magnet using a spin echo sequence. Sagittal and oblique sagittal slices were made perpendicular to the articular surfaces of the intertarsal joints and were analysed using image analysis software to measure the proportion of dense subchondral bone in the dorsal facet of each bone. Mean +/- s.d. percentage area of dense subchondral bone in the dorsal facet of the central tarsal bone in Group 1 was 47 +/- 8 medially, 46 +/- 4 sagitally and 50 +/- 11 dorsolaterally, whereas in Group 2 it was 39 +/- 16 medially, 43 +/- 8 sagitally and 53 +/- 7 dorsolaterally. For the third tarsal bone mean +/- s.d. percentage area of dense subchondral bone in Group 1 was 32 +/- 10 medially, 39 +/- 11 sagitally and 44 +/- 8 dorsolaterally, whereas in Group 2 it was 28 +/- 8 medially, 37 +/- 6 sagitally and 41 +/- 9 dorsolaterally. There was no significant difference in percentage area of dense subchondral bone between the trained and untrained horses. An effect of treadmill training of Thoroughbred horses on modelling of the central and third tarsal bones could not be demonstrated.

Animals↗

PubMed1998

The diagnosis of lameness associated with distal limb pathology in a horse: a comparison of radiography, computed tomography and magnetic resonance imaging.

A cadaver limb from an eight-year-old horse with right forelimb lameness that was relieved with an intra-articular distal interphalangeal joint block was imaged with radiographs, spiral computed tomography (CT) and magnetic resonance imaging (MRI). Spiral CT demonstrated several lucencies within the deep digital flexor tendon immediately proximal to the navicular bone. On MRI these areas had increased signal and there was enlargement of the tendon at this site. Effusion in the proximal interphalangeal joint and navicular bursa and thinning of the fibrocartilage of the navicular bone were also observed on MRI images. These changes were not detected on radiographs. Histopathology confirmed that there were focal areas of collagen necrosis within the deep digital flexor tendon with thinning and degenerative changes in the fibrocartilage of the navicular bone.

Animals↗

PubMed1998

A missense mutation in the zinc-finger domain of the human hairless gene underlies congenital atrichia in a family of Irish travellers.

Congenital atrichia is a rare, recessively inherited form of hair loss affecting both males and females and is characterized by a complete absence of hair follicles. Recently, a mutation in the human hairless gene was implicated in the pathogenesis of congenital atrichia. The human hairless gene encodes a putative single zinc-finger transcription-factor protein with restricted expression in brain and skin, which is believed to regulate catagen remodeling in the hair cycle. In this study, we report the identification of a missense mutation in the zinc-finger domain of the hairless gene in a large inbred family of Irish Travellers with congenital atrichia. The mutated arginine residue is conserved among human, mouse, and rat, suggesting that it is of significant importance to the function of the zinc-finger domain.

Alopecia↗

PubMed1998

Forced migration and destination choice: Armenian forced settlers and refugees in the Russian Federation.

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Behavior↗

PubMed1998

Neutrophils rolling on immobilised platelets migrate into homotypic aggregates after activation.

Interactions between platelets and leucocytes are implicated in the pathology of thrombotic vascular disease. Using a flow-based adhesion assay we have investigated a novel route for the formation of neutrophil aggregates on the surface of immobilised activated platelets. Neutrophils perfused over a platelet monolayer formed numerous rolling attachments but rapidly stopped and spread after the superfusion of N-formyl-methionyl-leucyl-phenylalanine or platelet-activating factor (both at 10(-7) M). Subsequent integrin-mediated migration across the platelet monolayer enabled formation of homotypic neutrophil aggregates, which was significant within 2.5 min of receipt of either stimulus. Aggregates increased in size with time and had an average projected area of approximately 500 microm2 after 10 min. Increasing size was correlated with an increasing tendency for movement downstream and large aggregates sometimes tumbled in that direction. The formation and stability of homotypic aggregates was dependent on several adhesive mechanisms. Antibody blockade demonstrated that interactions involving CD11a/CD18 and ICAM-3, between alpha(v)beta3-integrin and CD31 and between L-selectin and an unidentified counter-ligand were all required for the complete aggregatory response. Furthermore, blockade of L-selectin allowed initial aggregation which then reversed, suggesting that this receptor might regulate the interactions between other adhesion molecules that directly supported cell-cell adhesion. We propose that this novel route for leucocyte aggregation could promote vascular occlusion in thrombotic vessels or at distal sites in the event of embolisation.

Antibodies, Monoclonal↗

PubMed1997

Cross-talk between cell adhesion molecules regulates the migration velocity of neutrophils.

BACKGROUND: Although the adhesive mechanisms underlying the capture and immobilization of circulating neutrophils in inflamed blood vessels have been well described, factors controlling the subsequent migration of neutrophils over and through the blood vessel endothelium are poorly understood. Directional rearrangement of the actin cytoskeleton within the neutrophil, along with modulation of integrin-mediated adhesion, are necessary for neutrophil migration. Signals from chemotactic agents and from the adhesive substrate may regulate these processes, but little is known about their relative importance or their mode of integration. RESULTS: We examined the kinetics of neutrophil migration after formyl tripeptide or platelet-activating factor was perfused over neutrophils that were already rolling on the adhesion molecule P-selectin, which was presented either on the surface of immobilized platelets or in purified form coated on glass capillaries. Upon activation, neutrophils stopped rolling, spread and began to migrate; each of these processes was dependent on beta2 integrin (CD11b/CD18). The rate of migration increased over a period of about 8 minutes and was modulated directly by both the P-selectin and the CD31 surface receptors. Antibody blockade of either CD31 or P-selectin on platelets resulted in a reduction in the velocity of migration, and simultaneous blockade of both receptors reduced velocity further. Purified CD31 and P-selectin (but not a control adhesion molecule, ICAM-1) increased migration velocity in a concentration-dependent and additive manner that reconstituted the migratory behaviour observed on platelets. CONCLUSIONS: These studies show that binding of ligands to CD31 and/or P-selectin modifies the rate of integrin-supported neutrophil migration. This novel example of 'cross-talk' between surface receptors suggests that cell adhesion molecules might generally transduce accessory signals between adjacent cells to modify their migratory responses to chemotactic signals.

Animals↗