[Effects of Radix angelicae sinensis on systemic and portal hemodynamics in cirrhotics with portal hypertension]

The present study investigated effects of Radix angelicae sinensis (RAS) on systemic and portal hemodynamics in cirrhotic patients with portal hypertension. The results demonstrated that, after intravenous injection of the agent (20 mg.kg-1.min-1), systemic hemodynamics (heart rate, mean arterial pressure, inferior vena cava pressure, systemic vascular resistance, cardiac output, cardiac index) remained unchanged, but portal hemodynamics signicantly improved, wedged hepatic venous pressure (WHVP) (3.79 +/- 0.76 kPa vs 2.72 +/- 0.89 kPa, P < 0.01) and hepatic venous pressure gradient (HVPG) (2.88 +/- 0.73 kPa vs 1.78 +/- 0.68 kPa, P < 0.01) reduced by 29.40 and 35.78 percent respectively. However, anti-portal hypertensive effect of RAS was inverse proportion to the basical level of WHVP or HVPG in the cirrhotics. We conclude that RAS can effectively decrease portal pressure and yet gives no influence on systemic hemodynamics in the cirrhotic patients with portal hypertension.

The nuclear matrix protein NMP-1 is the transcription factor YY1

NMP-1 was initially identified as a nuclear matrix-associated DNA-binding factor that exhibits sequence-specific recognition for the site IV regulatory element of a histone H4 gene. This distal promoter domain is a nuclear matrix interaction site. In the present study, we show that NMP-1 is the multifunctional transcription factor YY1. Gel-shift and Western blot analyses demonstrate that NMP-1 is immunoreactive with YY1 antibody. Furthermore, purified YY1 protein specifically recognizes site IV and reconstitutes the NMP-1 complex. Western blot and gel-shift analyses indicate that YY1 is present within the nuclear matrix. In situ immunofluorescence studies show that a significant fraction of YY1 is localized in the nuclear matrix, principally but not exclusively associated with residual nucleoli. Our results confirm that NMP-1/YY1 is a ubiquitous protein that is present in both human cells and in rat osteosarcoma ROS 17/2.8 cells. The finding that NMP-1 is identical to YY1 suggests that this transcriptional regulator may mediate gene-matrix interactions. Our results are consistent with the concept that the nuclear matrix may functionally compartmentalize the eukaryotic nucleus to support regulation of gene expression.

Iron regulates the intracellular degradation of iron regulatory protein 2 by the proteasome

Iron regulatory proteins (IRP1 and IRP2) are RNA-binding proteins that bind to specific structures, termed iron-responsive elements (IREs), that are located in the 5'- or 3'-untranslated regions of mRNAs that encode proteins involved in iron homeostasis. IRP1 and IRP2 RNA binding activities are regulated by iron; IRP1 and IRP2 bind IREs with high affinity in iron-depleted cells and with low affinity in iron-repleted cells. The decrease in IRP1 RNA binding activity occurs by a switch between apoprotein and 4Fe-4S forms, without changes in IRP1 levels, whereas the decrease in IRP2 RNA binding activity reflects a reduction in IRP2 levels. To determine the mechanism by which iron decreases IRP2 levels, we studied IRP2 regulation by iron in rat hepatoma and human HeLa cells. The iron-dependent decrease in IRP2 levels was not due to a decrease in the amount of IRP2 mRNA or to a decrease in the rate of IRP2 synthesis. Pulse-chase experiments demonstrated that iron resulted in a 3-fold increase in the degradation rate of IRP2. IRP2 degradation depends on protein synthesis, but not transcription, suggesting a requirement for a labile protein. IRP2 degradation is not prevented by lysosomal inhibitors or calpain II inhibitors, but is prevented by inhibitors that block proteasome function. These data suggest the involvement of the proteasome in iron-mediated IRP2 proteolysis.

Characterization and expression of iron regulatory protein 2 (IRP2). Presence of multiple IRP2 transcripts regulated by intracellular iron levels

Iron regulatory proteins (IRP1 and IRP2) are RNA-binding proteins that bind to stem-loop structures, termed iron-responsive elements (IREs), present in either the 5'- or 3'-untranslated regions of specific mRNAs. The binding of IRPs to 5'-IREs inhibits translation of mRNA, whereas the binding of IRPs to 3'-IREs stabilizes mRNA. To study the structure and regulation of IRP2, we isolated cDNAs for rat and human IRP2. The derived amino acid sequence of rat IPR2 is 93% identical with that of human IRP2 and is present in lower eukaryotes, indicating that IRP2 is highly conserved. IRP1 and IRP2 share 61% overall amino acid identity. IRP2 is ubiquitously expressed in rat tissues, the highest amounts present in skeletal muscle and heart. IRP2 is encoded by multiple mRNAs of 6.4, 4.0, and 3.7 kilobases. The 3'-untranslated region of rat IRP2 contains multiple polyadenylation signals, two of which could account for the 4.0-kb and 3.7-kb mRNAs. The 3.7-kb mRNA is increased in iron-depleted cells and occurs with a reciprocal decrease in the 6.4-kb transcript. These data suggest that the 3.7-kb mRNA is produced by alternative poly(A) site utilization in iron-depleted cells.

Water on the sun

High-resolution infrared spectra of sunspot umbrae have been recorded with the 1-meter Fourier transform spectrometer on Kitt Peak. The spectra contain a very large number of water absorption features originating on the sun. These lines have been assigned to the pure rotation and the vibration-rotation transitions of hot water by comparison with high-temperature laboratory emission spectra.

Electrochemically accelerated adsorption of serum albumin on the surface of platinum and gold electrodes

Adsorption of serum albumin on the surface of platinum and gold electrodes was highly accelerated by the application of a constant potential to the electrodes. The accelerated adsorption was significant at the electrode potential of 0.5-1.0 V vs. Ag/AgCl, even in the diluted solution of albumin (0.01%).

Iron regulates cytoplasmic levels of a novel iron-responsive element-binding protein without aconitase activity

Iron-responsive element-binding proteins (IRE-BPs) are cytosolic proteins that bind to a conserved RNA stem-loop, termed the iron-responsive element (IRE), that is located in the 5'- or 3'-untranslated regions of mRNAs involved in iron metabolism. Binding of the IRE-BP to 5'-IREs represses translation, whereas binding to 3'-IREs stabilizes the mRNA. The previously identified IRE-BP (BP1) contains a 4Fe-4S cluster and has sequence homology to mitochondrial aconitase. The 4Fe-4S cluster is important for iron-dependent regulation: BP1 containing iron has low affinity for the IRE and contains aconitase activity, whereas BP1 lacking iron has high affinity for the IRE, but lacks aconitase activity. A second IRE-BP (BP2) has been identified in rat tissues and cells and exhibits many of the hallmarks of an IRE-BP, including binding to the IRE and functioning as a translational repressor of IRE-containing RNAs. BP1 and BP2 RNA binding activities are decreased in extracts from cells treated with iron, indicating that BP1 and BP2 are negatively regulated by iron. Although BP1 and BP2 share similar characteristics, they differ in two significant ways. Unlike BP1 levels, which do not change when RNA binding activity decreases in response to iron, BP2 decreases to undetectable levels in extracts from cells treated with iron; and unlike BP1, BP2 does not have aconitase activity. These data indicate that BP1 and BP2 are distinct proteins that have similar specificity for IRE binding and that function similarly in translation, but are regulated by iron via different mechanisms.

Primary chronic angle-closure glaucoma in Chinese--a clinical exploration of its pathogenesis and natural course

Forty-three cases (86 eyes) of primary chronic angle-closure glaucoma were randomly selected. An additional 44 cases (77 eyes) of primary acute angle-closure glaucoma and 30 normal subjects (34 eyes) were also randomly enrolled as control groups for comparison in the clinical study. Ultrasonic biometric measurements of the anterior chamber depth, lens thickness and axial length of the eyeball were performed. Using an potic microgauge attached to the slit-lamp, the entrance of anterior chamber angle was also calculated. The clinical manifestations and the natural course, including the characteristic appearance of anterior chamber angle, the form of peripheral anterior synechia as well as the facility of outflow, were carefully investigated. There were significant differences in the biometric parameters of the anterior segment of eye among above three groups. The facts reveal that the anatomic features of eyeball, especially in the anterior segment differentiate from those of primary acute angle-closure glaucoma. Follow-up study for the early stage cases showed that topical administration of miotics and/or peripheral iridectomy can effectively prevent iris from forming peripheral anterior synechia and thus halt its development. The criteria of diagnosis and the principles of prevention and treatment at the early stage cases were presented. The pathogenesis was discussed. We emphasized that the progressive stage after intermittent attacks of primary acute angle-closure glaucoma should not be confused with primary chronic angle-closure glaucoma.

[Immunological identification of tiger-bone]

Anti-tiger sera were prepared by using tiger serum proteins to immunize the rabbits. Tiger-bone can be identified by the specific serological reaction between the anti-tiger sera and the tiger-bone proteins.

[Effect of pituitrin or phentolamine alone or in combination on WHVP and systemic hemodynamics in patients with liver cirrhosis]

We observed the effect of pituitrin and phentolamine alone or in combination on wedged hepatic venous pressure (WHVP) and systemic hemodynamics in 28 patients with cirrhosis. The results showed that either of these drugs used separately could lead to reduction in WHVP, each of them could also cause by-effects on systemic hemodynamics. When pituitrin in combination with phentolamine was administered, no change could be found in inferior vena cava pressure, mean arterial pressure, pulse rate and cardiac index. This suggested that pituitrin in combination with phentolamine could not only efficaciously decrease WHVP, but also counteract side effects on systemic hemodynamics of each other and improve hepatic microcirculation. Our study provided evidence for the usefulness of the combination of the two drugs in controlling bleeding from esophagus varices.