Lymphatic sinusoids exist in chick but not in rabbit choroid

Purpose: Although it is generally thought that lymphatics do not exist in the choroid, there is mounting evidence that lymphatic-like structures do exist in primates and fowl. Methods/Results: Our comparison of the ultrastructure of chick and rabbit outer choroid indicates that major differences exist in the non-vascular areas of the choroid: notably, the chick has large lymphatic sinusoids, whereas the rabbit only has a system of large vacuoles contained within the processes of individual fibroblasts. Conclusions: These results raise questions regarding the similarities or otherwise between species of the management of retinal metabolites, excess tissue fluid and choroidal homeostasis, especially during conditions of overload.     

Nifedipine improves recovery function of kidneys preserved in a high- sodium, low-potassium cold-storage solution: study with the isolated perfused rat kidney technique

BACKGROUND: Extracellular types (high-Na) of cold-storage solution (CSS) have been shown to be more effective in preserving kidneys than intracellular CSS (high-K). On the other hand, calcium entry blockers (CEB) have been demonstrated to improve graft function when administered after and/or prior to transplantation. The ischaemia reperfusion syndrome involves, in part, an alteration in intracellular calcium metabolism that induces an increase in renal vascular resistances (RVR) and other cellular dysfunction, and high-K CSS per se are vasoconstrictive. Since CEB act via a modification in intracellular calcium metabolism on vascular smooth muscle, glomerular, and tubular cells, we evaluated the actual benefit on CEB on kidneys preserved in Belzer's CSS (K-UW) and a high-Na version of Belzer's CSS (Na-UW). METHOD: The isolated perfused rat kidney (IPK) was used, first as a vascular bed to test the effects of CSS on RVR, and the influence of nifedipine. Second, the recovery function of the IPK was assessed by GFR and tubular Na reabsorption, after 24 h preservation in K-UW and Na- UW, with or without nifedipine. Results were compared with a control group in which renal function was measured without prior cold-storage. RESULTS: K-UW but not Na-UW induced an increase in RVR when flushed into the kidney. This vasoconstriction is prevented by nifedipine. K-UW CSS was more deleterious to renal function than Na-UW. Addition of nifedipine to the flush, the CSS for 24 h, and to the normothermic reperfusate further improved recovery function of the IPK cold stored in Na-UW but not in K-UW, without any modification of RVR. CONCLUSION: Nifedipine may be of potential effect in attenuating ischaemic injury by a mechanism which does not involve its vasodilatory properties.      

Multicoil array for high resolution imaging of the breast

An RF multicoil array for high resolution imaging of the breast is presented. The RF multicoil is incorporated into a dedicated breast imaging apparatus that holds either breast in gentle compression during imaging. Simulations and imaging experiments demonstrate the high sensitivity and RF homogeneity of the multicoil array. Direct comparisons are made between the multicoil and a surface coil. In vivo images are presented to demonstrate the homogeneity of the RF field of the multicoil over the entire breast. An in vivo image of both high temporal and spatial resolution is shown, which demonstrates the sensitivity of the RF multicoil array that may be achieved in a practical imaging experiment.     

Image-guided pleural biopsies: indications, technique, and results in 23 patients

Twenty-six pleural biopsies were performed on 23 patients over a 3-year period. Twenty-three biopsies were performed guided with ultrasound; one, with computed tomography; and two, with fluoroscopy. Indications for an image-guided pleural biopsy were (a) pleural masses or thickening that were either not seen on chest radiographs or seen only on one view and (b) small or loculated pleural effusions of unknown cause with no mass seen. If only pleural fluid was present, reverse bevel needles were used for biopsy (n = 15). If a discrete pleural mass or thickening was seen with cross-sectional imaging, standard (16-20 gauge) biopsy needles were used (n = 11). In the 23 patients, biopsy results were true positive in ten (nine with malignancy, one with tuberculous pleurisy), true negative in ten (confirmed either at subsequent thoracotomy or clinical follow-up), and false negative in three. Complications were few, with a significant pneumothorax occurring in two patients (8.7%). Image-guided biopsy of small pleural lesions and small pleural effusions can be performed by the radiologist who understands the special needles and techniques involved.     

几种因素在L-天冬酰胺酶化学修饰中对酶活力及抗原性的影响

为了寻求在较好地保持酶活力的同时解除L-天冬酰胺酶抗原性的方法,采用不同分子量的乙酸酐、右旋糖酐和单甲氧基聚乙二醇,作为修饰剂和不同的修饰方法对该酶进行了化学修饰。结果表明在保持酶活性和降低抗原性方面,大分子修饰剂右旋糖酐、单甲氧基聚乙二醇优于小分子乙酸酐,底物保护修饰优于直接修饰;活化PEG,优于活化PEG₁。在底物保护下的PEG,修饰酶其抗原性完全解除的同时,酶活力保持在30%以上。     

Repopulation of marrow after transplantation: MR imaging with pathologic correlation

Sixty-seven magnetic resonance (MR) studies of the lumbar spine were performed in 15 patients with bone marrow transplants, and the appearance of marrow regeneration on MR images was correlated with results of bone marrow biopsy and pathologic examination. After transplantation, T1-weighted MR images of vertebral marrow showed a characteristic band pattern consisting of a peripheral zone of intermediate signal intensity and a central zone of bright signal intensity. Reciprocal changes were identified on short inversion time inversion recovery images. At histologic examination the central zone corresponded to fatty marrow; the peripheral zone corresponded to a zone of regenerating hematopoietic cells. Posttransplantation T1 and T2 relaxation times of the entire vertebral marrow were calculated from the spin-echo images; no statistically significant trends in relaxation times were noted. Knowledge of the normal MR pattern of marrow regeneration after transplantation may be useful in screening for residual marrow disease, determining marrow engraftment, and differentiating marrow repopulation with normal versus malignant cells.     

Plasma proteins and lymphocyte phenotypes in long-term plasma donors

BACKGROUND: The possible effects of long-term plasma donation remain unknown, but it is important to investigate them so that donor safety is ensured. The purpose of this study was to determine if long-term plasma donation alters plasma proteins or lymphocyte phenotypes. STUDY DESIGN AND METHODS: Two groups of long-term plasma donors, source plasma donors (n = 20) and Rh immune globulin plasma donors (n = 26), were compared with whole blood donors (n = 29) and nondonor controls (n = 30). Blood samples were obtained prior to donation. Serum protein, albumin, globulin, and immunoglobulin levels were determined. In an assay using whole blood, lymphocyte phenotypes were characterized with a panel of single- and dual-labeled monoclonal antibodies and subsequent analysis by flow cytometry. RESULTS: As compared to the nondonor controls and/or whole blood donors, the mean values for serum protein, globulin, and IgG levels were lower in both plasma donor groups, with a significant negative correlation between donation frequency and serum protein values for the source plasma donors. Albumin levels were within normal ranges for both groups of plasma donors. No significant differences existed among the donor groups in total white cell counts, the percentage or absolute number of lymphocytes, T (CD3) cells, or helper T (CD4) cells. However, there were increased percentages of B (CD19) cells and decreased percentages of suppressor T (CD8+/CD11b+) cells and natural killer cells in both groups of plasma donors as compared to nondonor controls. CONCLUSION: Many plasma donors have low levels of serum protein, globulin, and IgG. In addition, they have increased percentages of B cells and decreased percentages of suppressor T and natural killer cells. The clinical significance of these findings warrants further investigation.     

A new pathogenic mutation in the APP gene (I716V) increases the relative proportion of A beta 42(43)

We report a novel mutation in the amyloid precursor protein gene (APP I716V) which probably leads to familial early onset Alzheimer's disease with an onset age in the mid 50s. Cells transfected with cDNAs bearing this mutation produce more A beta 1-42(43) than those transfected with wild-type APP and this effect is additive with that of the previously reported APP V717I mutation thus providing a novel approach for further increasing A beta 1-42(43) in model systems.      

A pilot study of the human chorionic gonadotrophin test for ovarian hyperandrogenism

A controlled clinical study was designed to investigate the value of human chorionic gonadotrophin (HCG) challenge as a test for functional ovarian hyperandrogenism. Dexamethasone administration was followed by 5000 IU HCG and blood samples for steroid hormone assay were obtained 0, 8, 16, and 24 h thereafter. Study subjects were normal women (n = 13); women with functional ovarian hyperandrogenism, defined by androgen excess, amenorrhoea and an increased 17-hydroxyprogesterone response to nafarelin (n = 6); and normal men (n = 4). The responses of 17-hydroxyprogesterone, androstenedione and testosterone to HCG in women with functional ovarian hyperandrogenism were significantly greater than in normal women. However, the 17-hydroxyprogesterone response to HCG in functional ovarian hyperandrogenism was significantly lower after HCG than after nafarelin. The oestradiol response was also significantly lower after HCG than nafarelin, although oestradiol concentration more than doubled in normal women as well as in women with functional ovarian hyperandrogenism. The responses to HCG confirm that functional ovarian hyperandrogenism abnormalities are luteinizing hormone (LH)-dependent. Therefore, the 17- hydroxyprogesterone response to HCG could represent a useful test for the diagnosis of ovarian hyperandrogenism. The lower 17- hydroxyprogesterone response to HCG than to nafarelin in functional ovarian hyperandrogenism suggests that a follicle-stimulating hormone (FSH)-responsive factor modulates thecal 17-hydroxyprogesterone secretion. The oestradiol response to HCG is consistent with HCG directly stimulating the oestradiol secretion by thecal cells.