Whole body MR imaging in ankylosing spondylitis: a descriptive pilot study in patients with suspected early and active confirmed ankylosing spondylitis

Background  

Ankylosing spondylitis is a chronic inflammatory rheumatic disorder which usually begins in early adulthood. The diagnosis is often delayed by many years. MR imaging has become the preferred imaging method for detection of early inflammation of the axial skeleton in ankylosing spondylitis.     

Retroviruses and schizophrenia in Jamaica

Reports of an 18-fold higher incidence of schizophrenia among second-generation Afro-Caribbeans, and especially Jamaican migrants in the United Kingdom were soon called “an epidemic of schizophrenia,” with the inference that a novel virus, likely to be perinatally transmitted, was a possible etiological agent. This intriguing observation led us to explore a possible link with human T-cell lymphotropic virus type one (HTLV-I), because it is a virus that is endemic in the Caribbean Islands, is perinatally transmitted, known to be neuropathogenic, and the cause of a chronic myelopathy (tropical spastic paraparesis/ HTLV-I associated myelopathy). We therefore examined inpatients at the Bellevue Mental Hospital, Kingston, Jamaica and did standard serological tests for retroviruses HTLV-I and HTLV-II and HIV-I and HIV-II on 201 inpatients who fulfilled ICD-9 and DSM III-R criteria for schizophrenia. Our results produced important negative data, since the seropositivity rates for HTLV-I, the most likely pathogen, were no greater than the seropositivity range for HTLV-I carriers in this island population, indicating that HTLV-I and the other retroviruses tested do not play a primary etiological role in Jamaican schizophrenics.     

Cytochemical localization of Mn2+-dependent pyrimidine 5'-nucleotidase activity in isolated rod outer segments

A cytochemical method was developed for localization in isolated rod outer segments of manganese-dependent pyrimidine 5'-nucleotidase (MDPNase), an enzyme activity with possible relevance to shedding that we recently reported in photoreceptors and retinal pigment epithelial (RPE) cells in the intact rat retina. The purpose of this study was to eliminate the possibility that the previously observed cytochemical staining of the rods was due to diffusion of reaction product from the RPE cell lysosomes, which were also heavily stained. Rod outer segments (ROS) were isolated on continuous sucrose gradients from retinal homogenates prepared from rats raised in cyclic light (12 hr light:12 hr dark) and killed during the first 2 hr after light onset. ROS-containing bands were removed from the gradients and the isolated rods were fixed in 0.25% glutaraldehyde and pelleted. Chopped sections of the pellets were incubated in cytochemical medium for MDPNase activity and processed for light- and electron-microscopic localization of the enzyme activity. Two patterns of cytochemical staining were seen in ROS isolated from retinas obtained at this time of day. A few of the pellets contained clusters of ROS that were heavily coated along their surfaces and seemingly interconnected by thick strands of highly reactive extracellular material that displayed a punctate pattern of cytochemical staining. This material may have originated from the apical processes of the RPE cells, which were heavily stained in tissue fixed in situ around the time of light onset. The second staining pattern, visible only by electron microscopy, was more commonly observed. In the majority of the isolated ROS profiles, discrete streaks of cytochemical reaction product were seen in association with the internal aspects of the discs, at sites that seemed to correspond to the rims, and to narrow zones within the disc interiors. This distribution of reactive sites closely resembled that observed over most of the length of the ROS in the intact retina fixed at the same time of day. Occasionally, ROS profiles were encountered in which additional reactive sites were localized to the interdisc spaces between the plasma membrane and the rims of the discs. The latter pattern resembled the distribution of reaction product seen during this period over the tips of the ROS fixed in situ. As in the intact retinas, the cytochemical staining of the isolated ROS was inhibited by fluoride ions and strongly stimulated by manganese ions.(ABSTRACT TRUNCATED AT 400 WORDS)     

Abnormal neuromuscular junctions in the lateral rectus muscle of wobbler mice

We have studied the lateral rectus muscles and neuromuscular junctions (NMJs) of abducens motoneurons in wobbler (wr/wr) mutant mice from 26 to 58 days of age. The muscles of wr/wr weighed about 70% of the weight of littermate controls and were composed of fiber types comparable to those of controls, as assayed by succinate dehydrogenase activity. The most obvious difference between wr/wr and control NMJs was a reduction in the length of the postjunctional membrane of wr/wr mice. The mutant muscle endplate membrane was only about 70% (6.58 micron) the length of control muscle regions (9.44 micron). There were no obvious differences at the light microscopic level in the distribution of acetylcholine (ACh) receptors at junctional regions or staining of acetylcholinesterase, as assayed with alpha-bungarotoxin binding or enzyme histochemistry. Indirect immunocytochemical studies using antibodies directed against the subunits of the ACh receptor failed to indicate an abnormal presence of immature receptors clustered at the NMJs of wr/wr mice. Our findings suggest that the formation or maintenance of normal postjunctional folds and the differentiation of receptors at the junctions are under independent control during development. Furthermore, the wobbler mutation may affect muscle cell differentiation as well as neuronal differentiation. This mutant mouse should prove a useful model for study of postjunctional fold formation and function.     

Characterization and phenotypic analysis of differentiating CD34+human bone marrow cells in liquid culture

Abstract: Our current understanding of human haematopoietic stem cell biology is based in part on the characterization of human CD34⁺ bone marrow cell differentiation in vitro. CD34 is highly expressed on early stem cells and haematopoietic progenitor cells with clonogenic potential and is gradually lost during differentiation and commitment. However, CD71 (transferrin receptor) is expressed at low levels on early stem cells and generally increases during haematopoietic progenitor cell proliferation. We reasoned that the combination of these surface markers would provide a useful framework for the simultaneous analysis of multiple lineage differentiation of CD34⁺ haematopoietic progenitor cells in liquid culture. In this report, we identify the phenotype of distinct subpopulations of myeloid, erythroid and lymphoid cells in liquid suspension culture using differential expression of CD34 vs. CD71 in combination with specific lineage markers. Freshly isolated human CD34⁺ bone marrow cells were introduced into suspension culture and monitored over a 6-d period using 3-colour flow cytometry. This is the first demonstration that differential expression of CD34 vs. CD71 can be used to simultaneously monitor differentiation of multiple haematopoietic cell lineages in liquid suspension culture, facilitating the study of cytokine-, drug- or chemical-induced alterations in haematopoietic progenitor cell differentiation in vitro.