Method for the quantitative assessment of contrast agent uptake in dynamic contrast-enhanced MRI

In previous papers relative signal intensity increase was used as a quantitative assessment parameter for contrast uptake in contrastenhanced MRI. However, relative signal intensity increase does not only reflect contrast uptake but depends also on tissue parameters (native T₁ relaxation time) and sequence parameters (repetition time and flip angle); thus, the contrast uptake cannot be assessed accurately using relative signal intensity increase. Based on an analysis of the contrast behavior of spoiled gradient echo sequences, a method is described in this paper that overcomes the limitations of relative signal intensity increase measurement. A parameter, called “enhancement factor” (EF) is introduced that approximates differential T₁ relaxation rate. The enhancement factor scales linearly with contrast uptake and is independent of tissue and sequence parameters. The additional measurement time involved in determining the enhancement factor is less than 1 min and computation is straightforward. The practicality of the new method was confirmed by phantom measurements using T₁-weighted and proton density-weighted spoiled gradient echo sequences (FLASH-2D). Enhancing tissues were simulated by water phantoms doped with increasing concentrations of Gd-DTPA.     

Mesodermal dysgenesis

The authors present an account on a 12-year-old girl with ectomesodermal dysgenesis of the Rieger type syndrome. The disease was manifested at the age of nine months by transient diffuse corneal opacity, while the intraocular pressure was normal. In addition to typical corneal changes and changes in the angle of the chamber other associated somatic symptoms included megalocornea, high myoptic astigmatism, cleft soft palate, hypoplasia of the upper jaw, partial anodontia, marked thoracic kyphosis, scoliosis, generalized hypermobility and taxicity of the joints and torticollis. Examination revealed an uncommon pathological karyotype 46, XX, t/1,4 (p36, q23). Cytogenetic examination of the parents and siblings of the proband did not disclose any numerical or structural aberrations. The authors reflect on possible causes of the development of the disease and on the differential diagnosis.     

Prophylactic effect of a Beta vulgaris extract on experimental influenza infection in mice

An aqueous Beta vulgaris extract was repeatedly administered to mice by intranasal (i.n.) instillation, prior to i.n. inoculation of influenza virus A/PR/8/34 (H1N1). The extract conferred a partial protection against the experimental influenza infection: there was a significant decrease in the hemagglutination titers recorded in mouse lung homogenates, a decrease in mortality rate and an increase in the mean survival time as compared with the untreated, virus-inoculated controls.     

Synthesis and post-translational modification of the androgen receptor in LNCaP cells

Androgen receptor synthesis and modification were studied in the human LNCaP cell line. Immunoblotting with a specific polyclonal antibody showed that the androgen receptor migrated as a closely spaced 110–112 kDa doublet on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. Most of the receptor protein is present in the higher molecular mass form. Pulse labelling experiments with [³⁵S]methionine showed that the androgen receptor is synthesized as a single 110 kDa protein which is rapidly converted to a 112 kDa protein. Alkaline phosphatase treatment of cytosols from [³⁵S]methionine pulse labelled cells caused a gradual elimination of the 112 kDa isoform with a concomitant increase of the 110 kDa isoform. This indicates that the observed 110 to 112 kDa upshift of the newly synthesized androgen receptor reflects receptor phosphorylation. Both isoforms can bind hormone and can undergo a hormone dependent transformation to a tight nuclear binding form, indicating that the 110 to 112 kDa conversion is not an obligatory step for hormone binding or receptor transformation.     

Central processing of sex pheromone,host odour,and oviposition deterrent information by interneurons in the antennal lobe of female Spodoptera littoralis (Lepidoptera: Noctuidae)

Physiological and anatomical characteristics of antennal lobe interneurons in female Spodoptera littoralis (Boisd.) were investigated using intracellular recording and staining techniques. Responses of local interneurons and projection neurons to female sex pheromone components, host plant odours, and behaviourally active oviposition deterrents were recorded. We found local interneurons and projection neurons that responded specifically to only one or two of the tested odours, but we also found less specific cells, and neurons that responded to most of the tested odourants. These findings show that there are not only specific olfactory pathways in female moths up to the protocerebral level, but also that integration can begin in the antennal lobe. No correlation was found between the degree of specificity of either local interneurons or projection neurons and their respective morphological characteristics. Specialized and unspecialized local interneurons arborized throughout the antennal lobe. Specialized and unspecialized projection neurons had uniglomerular arborizations in the antennal lobe and sent their axons to the calyces of the mushroom body, and to the lateral horn of the protocerebrum. One specific projection neuron had multiglomerular arborizations and projected only to the lateral horn of the protocerebrum. Projection neurons arborizing in the glomeruli closest to the entrance of the antennal nerve always responded to pheromone components. No other correlations were found between the arborization pattern of projection neurons in the antennal lobe or in the protocerebrum and their response characteristics. The sensitivity of local interneurons and projection neurons was in the same range as that of receptor neurons in olfactory sensilla on the antennae, suggesting a much lower convergence in the central nervous system in females than in the pheromone-processing pathway in males. © 1994 Wiley-Liss, Inc.     

A promising technique for transplantation of bone marrow-derived endothelial progenitor cells into rat heart.

OBJECTIVE: To investigate the feasibility of intracoronary application of endothelial progenitor cells and the subsequent distribution within the heart. METHODS: Endothelial progenitors cells (EPCs) cultured from rat bone marrow were identified by double-positive staining with Dil-Ac-LDL and BS1-lectin. Twenty-four hours before cell transplantation, EPCs were labeled with 5-bromo-2'-deoxyuridine (BrdU). Cells (5 x 10(5) in 250-microl medium) were injected into healthy rats, either as intracoronary application (n=11) or as intramyocardial injection (n = 6). At 15 min or 3 days posttransplantation, hearts as well as other organs (lung, liver, kidney, and spleen) were collected and processed for subsequent BrdU immunohistochemistry. The number of BrdU-positive cells per tissue area was counted. RESULTS: Compared to intramyocardial injection, intracoronary administration resulted in more than twice as much positive cells in the heart (P < .05), with no local differences within the heart. Whereas after 15 min, EPCs were equally distributed in all examined organs (except for the spleen), cells that were still present after 3 days, approximately 10%, were selectively restricted to the heart. CONCLUSIONS: Our data indicate that the intracoronary application provides a promising technique for EPC transplantation in the rat heart.