Digital radiographic imaging system with multiple-slit scanning x-ray beam: preliminary report

A digital imaging system that employs a novel scanning x-ray tube, a multiple-slit assembly (MSA), and an image intensifier (II)-TV digital system is described. Use of the MSA can increase x-ray utilization by a factor of 100 over that obtained with single-slit systems. Scatter and veiling glare can be reduced substantially by synthesizing the final image from a number of multiple-slit images, resulting in improvement in contrast sensitivity. An experimental prototype system consisted of a conventional x-ray tube and an II-TV digital system used in conjunction with mechanical scanning of the MSA. Attenuation curves measured with an aluminum stepwedge showed that scatter and veiling glare were eliminated by this approach. Reconstructed images of phantoms were superior to images obtained with conventional wide-beam exposure. Physical parameters related to design of the scanning x-ray tube and a digital system for acquiring images of the chest are discussed.     

Blood pressure independent effects of nitrendipine on cardiac structure in patients after renal transplantation

Left ventricular hypertrophy is well established as a blood pressure independent cardiovascular risk factor in patients on renal replacement therapy. The effects of antihypertensive treatment on myocardial structure and function in renal transplant recipients have been so far only rarely investigated. In a double-blind, placebo-controlled study patients were randomized to the calcium channel blocker nitrendipine or placebo if the transplanted kidney had developed a stable phase. Normotensive patients received nitrendipine 2 x 5 mg daily or placebo, hypertensive patients received 2 x 10 mg up to 2 x 20 mg nitrendipine daily or placebo. To achieve adequate blood pressure control, all patients with still elevated blood pressure on study medication received antihypertensive drugs other than calcium channels blockers. Ambulatory blood pressure recording and 2D-guided M-mode echocardiography were performed at baseline and upon completion of the study. In addition, laboratory workup (including serum creatinine and lipids) was done, and serum aldosterone, plasma renin activity, plasma angiotensin II and blood glucose levels were measured in all patients at baseline and after at least 12 months of therapy. Ambulatory blood pressure was almost identical between both groups at study baseline and follow-up. In renal transplant patients on nitrendipine, posterior wall thickness (-0.10 +/- 1.77 mm) and septal wall thickness (-0.83 +/- 2.23 mm) did not change significantly from baseline. In contrast, posterior wall thickness (0.71 +/- 0.92 mm, P < 0.01) and septal wall thickness (0.97 +/- 2.20 mm, P < 0.05) increased in patients on placebo, which differed from the observed changes on nitrendipine (ANOVA: P = 0.093 and P = 0.048, respectively). Relative wall thickness, a parameter for concentric left ventricular hypertrophy, became numerically smaller on nitrendipine therapy from 0.46 +/- 0.07 to 0.44 +/- 0.09 (-0.02 +/- 0.09, NS) but increased from 0.42 +/- 0.08 to 0.48 +/- 0.08 in the placebo arm (+0.04 +/- 0.08, P < 0.02), which was also significant between the two groups (ANOVA: P = 0.036). Endocrine parameters, lipids and blood glucose were not different between the two groups. We conclude from these data that the calcium channel blocker nitrendipine exerted beneficial effects on cardiac structure in patients after renal transplantation independent of blood pressure.      

旋光活性内酯化合物的研究:(—)MALYNGOLIDE的全合成

以己二酸为起始原料,成功地合成了有手性季碳中心的内酯化合物(—)-Mialyngolide(1),其中关键的步骤采用手性相转移催化剂进行立体选择烷基化反应,此合成路线短,总收率为10.5%。     

旋光活性内酯化合物的研究：（—）MALYNGOLIDE的全合成

以己二酸为起始原料，成功地合成了有手性季碳中心的内酯化合物（—）－Ｍｉａｌｙｎｇｏｌｉｄｅ（１），其中关键的步骤采用手性相转移催化剂进行立体选择烷基化反应，此合成路线短，总收率为１０．５％。     

Skeletal Alkaline Phosphatase Activity Is Primarily Released from Human Osteoblasts in an Insoluble Form, and the Net Release Is Inhibited by Calcium and Skeletal Growth Factors

Skeletal alkaline phosphatase (ALP) is anchored to membrane inositol-phosphate on the outer surface of osteoblasts. Although skeletal ALP activity in serum is, essentially, all in an anchorless (soluble) form, in vitro studies indicate that ALP can be released in either an anchorless, soluble form (e.g., by a phospholipase) or an anchor-intact, insoluble form (e.g., by vesicle exocytosis). The current studies were intended to define the contributions of each of these putative processes of ALP release and to assess the significance of regulation by calcium (Ca) and skeletal effectors. ALP activity was measured in serum-free medium from replicate cultures of human osteosarcoma (SaOS-2) cells and normal human bone cells. Temperature-sensitive phase distribution (in Triton X-114) allowed separation of soluble from insoluble ALP activity. Our studies revealed that most of the ALP activity released from SaOS-2 cells was in an insoluble form (78% ± 8%), a percentage that was constant between 2 and 96 hours. A similar result was seen for normal human bone cells. Calcium had a negative, biphasic dose-dependent effect on net release of ALP activity: r=−0.85, P < 0.001 at 24 hours, with K_Iapparent values for biphasic inhibition of 20 and 300 μmol/l Ca. Of the skeletal effectors tested, insulin-like growth factor-II (IGF-II) had the greatest effect, decreasing the net release of ALP activity in a dose-dependent manner (r=−0.82, P < 0.005). Neither Ca nor IGF-II affected the distribution of soluble/insoluble ALP activity by more than 9%. IGF-II had no effect on extracellular ALP stability, but the addition of Ca to Ca-free cultures resulted in parallel losses of extracellular ALP activity and ALP immunoreactive protein (P < 0.001 for each). A similar effect was seen when Ca was added to Ca-free, cell-free, conditioned medium, but not when Ca was added to purified ALP, which is consistent with the general hypothesis that a Ca-dependent protease might be present in the cell-conditioned medium. Together, these data suggest that most of the ALP activity released from osteoblasts is insoluble (and, presumably, anchorless), net release of ALP activity is negatively regulated by Ca and skeletal growth factors, the effect of Ca may reflect Ca-dependent protease activity, and an exogenous (e.g., serum) phospholipase may be responsible for releasing ALP from its insoluble anchor. Received: 8 November 1997 / Accepted: 7 August 1997     

Immunoscintigraphy of inflammatory processes with a technetium-99m-labeled monoclonal antigranulocyte antibody (MAb BW 250/183)

Antigranulocyte immunoscintigraphy with a technetium-99m- (99mTc) labeled monoclonal antigranulocyte antibody (MAb BW 250/183) was performed in 34 in-patients of the departments of accident surgery and internal medicine in order to prove or exclude inflammatory processes. After labeling with 99mTc, 555 MBq, 99mTc-MAb (0.5 mg antibody) were slowly injected intravenously over a period of 5 min. A whole-body scan was done 4-6 hr postinjection, and planar or SPECT images were performed 6, 18, and 24 hr postinjection. Leukocyte immunoscintigraphy proved inflammatory suppurating processes in 20 cases (true-positive) and excluded them in 11 cases (true-negative). The findings were false-positive in two patients (hematoma without signs of infection, pseudoarthrosis) and false-negative in one patient (encapsulated lung abscess with pleural fibrosis). Anti-idiotypic human anti-mouse antibodies (HAMA) were found only in one out of 20 patients. According to our experiences, immunoscintigraphy with 99mTc-MAb BW 250/183 has a sensitivity of 95%, and is, therefore, well suited for the identification of leukocytic inflammations.     

Ia antigen is a differentiation marker on human eosinophils

Evidence suggests that the "la-like" or antigen is a differentiation marker that is expressed on early human hematopoietic precursor cells, but is absent on their mature progeny. The eosinophil precursor cell (CFU-EO) is distinct from the granulocyte-monocyte colon-forming cell (CFU-C). We provide data that indicate that the ia antigen is expressed on the human eosinophil colony-forming cells and is absent on mature eosinophils. All CFU-EO were inhibited in the presence of rabbit la antiserum at a titer of 1:30. Cytotoxicity was complement-dependent. The metamyelocytic eosinophil and more mature eosinophil forms did not express the la antigen.