Techniques for high-resolution MR imaging of atherosclerotic plaque

Atherosclerotic cardiovascular disease is the most common cause of death in the United States. Investigation of atherosclerotic plaque morphology and composition is important because the findings may be useful in predicting prognosis or response to therapy. This study presents high-resolution magnetic resonance (MR) imaging techniques developed on a 1.5-T whole-body imager with a custom-built surface coil, for characterizing the composition and morphology of plaque removed at carotid endarterectomy. The initial comparison of MR imaging and histologic results showed good correlation. In conjunction with MR angiography, these techniques could be used in in vivo imaging to define the size, location, and contents of atherosclerotic plaque at the carotid bifurcation.     

Investigation of the Photosensitive Child

Photosensitivity disorders in childhood frequently can be diagnosed and managed in the general dermatology clinic. Occasionally, when diagnostic doubt exists, referral to a specialist unit is required for diagnostic phototesting. Light testing equipment is fickle by nature, making such units uncommon. Phototesting using monochromator or provocation systems takes approximately 45 minutes. Immediate and delayed readings over the following 48 hours as appropriate are required to cover the diagnostic possibilities. Individual diseases are characterized by particular patterns of wavelength dependency and evolution of the abnormal response. Other investigations that may be required are autoantibodies to exclude lupus erythematosus, a porphyrin scan leading to full studies and, on occasion, cell mutation or survival, and chromosome studies for the rarer genophotodermatoses. Good investigative data frequently help clarify the common clinical variants.     

Inhibitory actions of GABA on rabbit urinary bladder muscle strips: mediation by potassium channels.

1. The actions of gamma-aminobutyric acid (GABA) upon rabbit urinary bladder muscle were investigated to determine whether they were mediated through potassium channels. 2. In vitro experiments were undertaken in which bladder muscle strips were caused to contract with carbachol. Addition of GABA or baclofen reduced the size of such evoked contractions in the case of GABA by 20.7 +/- 3.2%, in the case of baclofen by 22.4 +/- 2.2%. 3. Electrical stimulation of autonomic nerves in bladder wall strips also evoked contractions which were significantly smaller in potassium-free Krebs solution. The size of contractions produced by carbachol on the other hand were unaffected by the absence of potassium in the Krebs solution. 4. The inhibitory actions of GABA and baclofen on carbachol-induced contractions of bladder muscle were detected at much lower concentrations in potassium-free compared with potassium containing solutions. 5. The inhibitory effects of baclofen were completely reversed by tetraethyl ammonium chloride between 1 and 5 mM, caesium chloride between 0.5 and 3 mM and barium chloride between 0.5 and 2.5 mM. The actions of baclofen were only partially reversed by 4-amino-pyridine between 1 and 5 mM. 6. It was concluded that the GABAB receptor-mediated inhibitory actions on rabbit urinary bladder smooth muscle cells were produced by activation of potassium channels.     

Total hip reconstruction in a woman with Cornelia de Lange syndrome: a case report.

More than 250 cases of Cornelia de Lange syndrome have been reported in the medical literature, but not have described the use of hip reconstruction to correct the congenital dysplasia that may be associated with this condition. This article reports the application of a bipolar hemiarthroplasty and acetabular allograft reconstruction for a 32-year old woman with congenital dysplasia and degenerative joint disease of the hip secondary to de Lange''s syndrome. On admission, she was in considerable pain and unable to bear weight on the affected extremity. Her Harris hip score was 25. Following surgical intervention and a well-designed plan of rehabilitation, the patient''s functional status improved markedly. Her Harris hip score was 72, and her pain was alleviated.     

A novel nucleotide-containing antigen for human blood γδ T lymphocytes

The stimulation of human γδ T cells by mycobacteria occurs through recognition of four distinct nonpeptide phosphorylated antigens termed TUBag1–4. Among these latter, TUBag4 has already been biochemically characterized as a γ-X derivative of 5′-deoxythymidine triphosphate (Constant, P., Davodeau, F., Peyrat, M. A., Poquet, Y., Puzo, G., Bonneville, M. and Fournié, J.-J., Science 1994. 264: 267). However, despite chemical synthesis of weakly stimulatory nucleotide-containing analogs, these mycobacterial compounds remained the sole nucleotide-containing antigens actually isolated from natural sources. Here, we present the complete isolation of the TUBag3 antigen from Mycobacterium fortuitum and demonstrate that this nonpeptide molecule contains a 5′-UTP nucleotide moiety. On selected Vγ9/Vδ2 clones, T cell responses can be triggered with nanomolar concentrations of TUBag3. Like crude mycobacterial extracts, this purified nucleotide conjugate elicits a strong polyclonal response of γδ PBL from healthy donors. Furthermore, we present evidence that this compound is distinct from the recently synthesized γ-isopentenyl 5′-UTP, a nucleotide conjugate of isopentenyl pyrophosphate that was found to be stimulatory for human γδ T cells (Tanaka, Y., Morita, C. T., Tanaka, Y., Nieves, E., Brenner, M. B. and Bloom, B. R., Nature 1995. 375: 155). Since it appears that both mycobacterial nucleotide antigens are molecules structurally related to peculiar precursors of nucleic acid synthesis, we propose that TUBag-reactive T cells might be specifically devoted to surveillance of proliferating cells.     

Improved immediate function of renal allografts with Belzer perfusate

The characteristics of 254 cadaveric kidneys were evaluated and the incidence of immediate function identified. The Belzer perfusate was used primarily (n = 140) and secondarily (n = 14) in combination with pulsatile machine perfusion. These two groups were compared with a previous group of kidneys machine-perfused with silica gel (cryoprecipitated human plasma). The incidence of immediate function of the group primarily perfused with Belzer perfusate was statistically significantly improved over that of the silica gel. The secondarily perfused Belzer group, "imported" kidneys previously preserved with simple cold storage, had notably longer periods of preservation and higher resistances on the machine. However, 100% of this group functioned immediately. Other findings in this study show that the Belzer perfusate allows for improved parenchymal function posttransplant, as noted by a more rapid clearance of serum creatinine posttransplant. When comparing the immediate function group with those suffering early dysfunction, there is a statistically significant increased resistance on the machine in the latter group. This allows for prediction of immediate function based on perfusion characteristics of the kidney. The Belzer perfusate, composed of metabolic substrates for high-energy phosphate production, improves the incidence of immediate function in machine-perfused kidneys, as well as improved qualitative function posttransplant. It also is effective as a "rescue" mechanism in previously simple cold-stored (ATP-depleted) kidneys.     

Complex Ph1 translocation in chronic myeloid leukemia

This report describes a new case of chronic myeloid leukemia with an unusual Philadelphia chromosome translocation involving chromosomes No. 4,9, and 22; t(4,9,22) (q31;q34;q11).     

The effect of antigen deprivation on thymus-dependent and thymus-independent lymphocytes in the small intestine of the mouse

Isografts of foetal small intestine, implanted under the kidney capsules of adult mice grow normally and, despite the lack of intraluminal antigenic stimulation, are populated by thymus-dependent and thymus-independent lymphocytes. The Peyer's patches in these grafts are very small, lack germinal centres and can be shown to have small thymus-dependent areas.

Quantitative intraepithelial lymphocyte counts were carried out in normally sited small intestine of immunologically intact and thymus-deprived mice, and in grafts implanted in intact and thymus-deprived mice. Counts were also performed in a group of neonatally thymectomized and control mice. The results show a significant depletion of intraepithelial lymphocytes in neonatally thymectomized mice, and a profound reduction in numbers of intraepithelial lymphocytes in grafts, deprived of antigen, when compared with normally sited intestine of the same age.