Central nervous system control of intraocular pressure

Summary— Normal intraocular pressure (IOP) is the result of an equilibrium between aqueous humor (AH) production, AH outflow and episcleral venous pressure. Most available antiglaucoma agents produce their effects by interacting with autonomic mechanisms (beta-blockers, epinephrin or parasympathomimetics). In contrast, the role of the central nervous system (brain and nerves) in the regulation of IOP remains unclear in view of the complex haemodynamic, metabolic or hormonal changes which occur under experimental conditions. In this paper, we discuss a basic understanding of the anatomic and physiological relationships between central nervous system and IOP and describe how the brain can affect functions in ciliary body and trabeculum meshwork.     

仙茅的酚性甙成分研究

从仙茅科仙茅(Curculigo orchioides Gaerth.)根茎的水溶性部位中,分离得到一个新的酚性甙和两个新的含氯酚性甙。经光谱(UV,IR.¹HNMR,^{13CNMR和MRMS,FAB-MS)解析及化学方法,确定了它们的结构,并且分别命名为仙茅甙乙(Curculigoside B),仙茅素B和C(curculigine B和C)。}     

Prevalence of heterozygotes for hemochromatosis in the white population of the United States

In previous studies, the prevalence of HLA-linked hemochromatosis, thought to be the most common genetic illness in whites, has been estimated by identifying homozygotes in the population. Because not all homozygotes express the disease phenotypically, the accuracy of these estimates is uncertain. We analyzed the distribution of transferrin saturation values in the second National Health and Nutrition Examination Survey to estimate the prevalence of hemochromatosis heterozygotes in the US population. After removing values for possible homozygotes, two populations were present (P < .01 for each gender). When weighted to reflect the US adult white male population as a whole, a proportion of 850 per 1,000 (95% confidence interval, 0.81 to 0.89) were included in a population with a lower mean saturation of 29.7% (29.1% to 30.3%), whereas 150 per 1,000 (0.11 to 0.19) comprised a population with a higher mean saturation of 47.0% (45.1% to 49.0%). Similar results were found for the female population. The gene frequencies were estimated to be 0.081 from the male population and 0.070 from the female population corresponding to prevalences of homozygotes of 6.6 and 4.8 per 1,000, respectively. Our results confirm that the gene for hemochromatosis is common.     

Cerebrospinal fluid-iophendylate contrast on gradient-echo MR images

The effect on the signal intensities of cerebrospinal fluid (CSF) and iophendylate (Pantopaque) and on CSF-iophendylate contrast was studied in vitro with a small-nutation-angle (alpha) gradient refocused magnetic resonance (MR) imaging technique (GRASS) as alpha, repetition time (TR), and echo time (TE) were varied. CSF signal intensity was consistently greater than that of iophendylate. Therefore, retained intraspinal iophendylate may be considered in the differential diagnosis of focal areas of low signal intensity at the periphery of the spinal canal on GRASS images. At constant TE and TR, an increase in alpha from 6 degrees to 45 degrees increased the signal intensities of CSF and iophendylate but decreased CSF-iophendylate contrast. At constant alpha and TR, an increase in TE from 13 to 28 msec decreased the signal intensities of CSF and iophendylate but increased contrast. At constant alpha and TE, an increase in TR from 50 to 400 msec increased the signal intensities of CSF and iophendylate, as well as contrast. Clinical examples of the contrast behavior of retained intraspinal iophendylate on both spin-echo and GRASS images corroborate the experimental findings. Retained intraspinal iophendylate may mimic the appearance of intra-or extra-dural lesions, magnetic susceptibility artifact, and flow on gradient-echo MR images of the spine.     

Granzyme B and perforin lytic proteins are expressed in CD34+ peripheral blood progenitor cells mobilized by chemotherapy and granulocyte colony-stimulating factor

Granzyme B and perforin are cytoplasmic granule-associated proteins used by cytotoxic T lymphocytes and natural killer (NK) cells to kill their targets. However, granzyme B gene expression has also been detected in a non-cytotoxic hematopoietic murine multipotent stem cell line, FDCP-Mix. The objective of the present study was to investigate whether granzyme B and perforin could be expressed in human hematopoietic CD34+ cells and if present, discover what their physiologic relevance could be. The primitive CD34+ human cell line KG1a was investigated first and was found to express granzyme B and perforin. Highly purified hematopoietic stem/progenitor cells were then selected using the CD34 surface antigen as marker. Steady-state bone marrow (BM) CD34+ cells did not contain these proteins. Peripheral blood (PB) CD34+ cells, which had been induced to circulate, were also analyzed. After chemotherapy (CT) and granulocyte colony-stimulating factor (G-CSF) treatment, CD34+ cells strongly expressed mRNAs and proteins of granzyme B and perforin. In contrast, CD34+ cells mobilized by G-CSF alone were negative. Western blot analysis further showed that granzyme B and perforin proteins were identical in CD34+ cells and activated PBLs. Such proteins might be implicated in the highly efficient migration of CD34+ stem/progenitor cells from BM to PB after CT and G-CSF treatment. The cellular adhesion mechanisms involved in the BM homing of CD34+ cells are disrupted at least temporarily after CT. The Asp-ase proteolytic activity of granzyme B on extracellular matrix proteins could be used by progenitor cells for their rapid detachment from BM stromal cells and perforin might facilitate their migration across the endothelial cell barrier.