Prevalence of antibodies to HTLV-I/II in blood donors and risk populations in South China.
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Blood Donors↗
Biomedical subjects
F Cao
Publications and source records attributed to F Cao.
A quantitative analysis of connexin-specific permeability differences of gap junctions expressed in HeLa transfectants and Xenopus oocytes.
Gap junctions provide direct intercellular communication by linking adjacent cells with aqueous pores permeable to molecules up to 1 kDa in molecular mass and 8-14 A in diameter. The identification of over a dozen connexins in the mammalian gap junction family has stimulated interest in the functional significance of this diversity, including the possibility of selectivity for permeants as seen in other channel classes. Here we present a quantitative comparison of channel permeabilities of different connexins expressed in both HeLa transfectants (rat Cx26, rat Cx32 and mouse Cx45) and Xenopus oocytes (rat Cx26 and rat Cx32). In HeLa cells, we examined permeability to two fluorescent molecules: Lucifer Yellow (LY: anionic, MW 457) and 4',6-diamidino-2-phenylindole, dihydrochloride (DAPI, cationic, MW 350). A comparison of the kinetics of fluorescent dye transfer showed Cx32, Cx26 and Cx45 to have progressively decreasing permeabilities to LY, but increasing permeabilities to DAPI. This pattern was inconsistent with selection based on physical size of the probe, nor could it be accounted for by the differences between clones in the electrical conductance of the monolayers. In Xenopus oocytes, where electrical and dye coupling could be assessed in the same cells, Cx32 coupled oocytes showed an estimated 6-fold greater permeability to LY than those coupled by Cx26, a comparable result to that seen in HeLa cells, where an approximately 9-fold difference was seen. The oocyte system also allowed an examination of Cx32/Cx26 heterotypic gap junction that proved to have a permeability intermediate between the two homotypic forms. Thus, independent of the expression system, it appears that connexins show differential permeabilities that cannot be predicted based on size considerations, but must depend on other features of the probe, such as charge.
Animals↗
Protein insolubility and late-stage morphogenesis in long-term postconfluent cultures of MDCK epithelial cells.
Epithelial morphogenesis in vitro has been studied in cultures soon after cell-cell contact at confluency when several actin-associated proteins (fodrin, adherens junction molecules E-cadherin and catenins) localize to specific subcellular domains and become resistant to extraction with non-ionic detergents. Here we demonstrate that early confluency is followed by a long postconfluent period of several weeks during which these proteins and actin itself become progressively enriched in the detergent-resistant fraction of MDCK epithelial cells. Cultures from another tissue (human retinal pigment epithelium) which produces weakly epithelialized monolayers in culture do not exhibit similar late-stage increases in protein insolubility. After confluency some cells in MDCK cultures undergo additional morphogenetic changes giving rise to cord-like structures, and the MDCK adherens junction becomes more stable to disrupting agents. These results indicate that in vitro morphogenesis is not restricted to early confluency in MDCK cells but rather molecular stabilization and dynamic changes in cell shape occur over a protracted postconfluent interval.
Adult↗
Full-field direct digital telemammography: technical components, study protocols, and preliminary results.
The early detection of breast cancer increases the survival rate in women. Today, film-screen mammography is the most common and effective technique for the detection of breast cancer. However, the film-screen image recording system of current mammography has several technical limitations that can reduce the breast cancer diagnostic accuracy. A state-of-the-art technology, full-field direct digital mammography (FFDDM) has the potential to increase the sensitivity of clinical and screening examinations and emerge as a film-screen mammography replacement. It is believed that efficiently delivering the superior image quality of FFDDM to expert mammographers will significantly increase the breast cancer diagnostic accuracy. This concept motivates the studies of FFDDM telemammography. In this paper, we will report the FFDDM telemammography project that is being conducted in our facility. The fundamental technology of the FFDDM system and the characteristics of FFDDM images are described. Our research approach is through three protocols: telediagnosis, teleconsultation, and telemanagement. Each of these study protocols is defined. To conduct this FFDDM telemammography project, an asynchronous transfer-mode-network-based telemammography system is developed across two remote campuses in our facility. The architecture of this system is detailed. Unlike other medical imaging modalities, the matrix of an FFDDM image is huge. How to present the image information to mammographers via currently available display media is a challenging task. Our display approaches for the FFDDM images are described. Some preliminary study results from the current phase of this study are reported.
Breast Neoplasms↗
[The value of determining guanine deaminase in diagnosis of hepatic diseases].
We determined the Guanine Deaminase (GD) activity of 200 patients with different diseases. It was found that GD activity of hepatic patients is higher than that of health adults, while the GD activity of other patients is in the normal range. There is a linear correlation between GD activity and ALT in patients with chronic hepatitis, billiary obstruction, and between GD activity and total bilirubin in patients with chronic active hepatitis, biliary obstruction and liver cirrhosis. Moreover, the GD activity of patients positive for anti-HCV is significantly increased. So GD activity in serum is a specific and sensitive index to estimating hepatic functions and can be used in the diagnosis of acute and chronic hepatitis, cirrhosis of liver, and C virus hepatitis.
Adult↗
[Change of the guaning nucleotide-regulating protein in substantia gelatinosa of spinal cord of rats after unilateral transection of dorsal roots and electroacupuncture: an immunohistochemical observation].
The Subunit alpha o of guanine nucleotide-binding protein (rabbit polyclonal antiserum 9120, K,J. Chang. USA), in the areas of rat spinal cord was localized by immunohistochemical PAP methods, and the changes of alpha o-immunoreactivity (alpha o-IR) in the substantia gelatinosa (SG) were observed after unilateral transection of dorsal roots and electroacupuncture. Intense alpha o-IR was presented in Rexed lamina I to III of the dorsal horn, and the highest alpha o-IR in lamina (SG), which was found than that in the normal and control animals. Iateral spinal nucleus of rat revealed higher density of alpha o-IR containing fiber networks. Following unilateral transection of dorsal roots and pain threshold increased significantly after electroacupuncture applied at the point "Huantiao", alpha o-IR was markedly decreased than that in the normal and control group in those areas. The optic density (OD) of alpha o-IR were measured, which decreased more markedly in opration and electroacupuncture group than that normal and control group. The results mentioned above indicate that Go-protein in terminals of primary nociceptive neurons of SG decreases markedly after dorsal roots transected and electroacupuncture. It was inferenced that partial Go-protein probably originates from the primary sensory neurons, and the release of "inhibitory" of Go may increase (with weaker alpha o-IR). In a work, Go might play important roles on the primary afferents informational regulation and electroacupuncture analgesia of the regulation.
Animals↗
The effect of acidified glucose nutrient solution on preservation of platelet concentrate.
The preservation effect of a new platelet solution--acidified glucose nutrient solution (AGN)--was tested by adding AGN to pooled platelet rich plasma (PRP) prior to preparation of platelet concentrates (PC). Each PRP unit was prepared from a unit of whole blood and four PRP of the same blood group were pooled in 400 ml volume PVC bags. Equal aliquots of each pooled PRP were made prior to preparation of PC. AGN was added to one aliquot and nothing was added to the control aliquot. Equal volume and concentration PC were then prepared and the PC were further aliquoted for storage at 22 degrees C. After five days, the parameters of platelet count, pH, aggregability and hypotonic shock response (HSR) for PC preserved in AGN plasma were better than those of the controls preserved in normal ACD plasma. The aggregability and HSR of AGN platelet concentrates recovered to baseline after two h of incubation with fresh plasma. The results of electron microscopy show that platelets preserved in AGN have less changes in morphology. The results of our work suggest that the preservation effect of AGN on PC is similar to the effect of using second generation containers or preparation of platelets from thrombocytapheresis.
Blood Platelets↗
Effect of atropine and PCPA on the behavioral modulation of paired-pulse response in the hippocampal CA1 region.
This study investigated the effect of cholinergic and serotonergic inputs on the paired-pulse response in hippocampal CA1 region of behaving rats. Paired-pulses were delivered to the Schaffer collaterals, at an interpulse interval (IPI) of 30 ms, and field responses were recorded at the proximal CA1 apical dendritic layer. Previously, paired-pulse facilitation of the CA1 population spike was shown to be significantly larger during walking than immobility. The muscarinic cholinergic antagonist, atropine sulfate (50 mg/kg i.p.), strongly attenuated this paired-pulse facilitation during walking at given amplitude of the population spike evoked by the first pulse. Parachlorophenylalanine (PCPA; 100 mg/kg i.p. for 3 days), an inhibitor of serotonin synthesis, alone did not change paired-pulse facilitation and the combined action of PCPA and atropine resembled that of atropine alone. The excitatory postsynaptic potentials did not change significantly with behavior or after drugs. Thus, we have shown that the behaviorally dependent modulation of paired-pulse response in the CA1 region is mediated primarily by a cholinergic and not a serotonergic input.
Analysis of Variance↗
[A survey of adverse effects of Chinese herbal drugs in China, 1915-1990].
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Anaphylaxis↗
Behavior-dependent paired-pulse responses in the hippocampal CA1 region.
Paired-pulses of 20-100 ms interpulse interval (IPI) were delivered to the Schaffer collaterals/commissural fibers in order to excite the apical dendrites of the hippocampal CA1 region in freely behaving rats. Significant differences were observed for the paired-pulse responses during different behavioral states. The responses recorded during awake immobility (IMM), and slow-wave sleep (SWS) were similar, but as a group, were different from those during walking (WLK) and rapid-eye-movement sleep (REM). During WLK and REM, the population spike evoked by the second pulse (P2) at IPI of 30 and 50 ms, was greatly facilitated as compared to the population spike evoked by the first pulse (P1), i.e. P2 greater than P1. During IMM and SWS and using moderate stimulus intensities, P2 was generally smaller than P1 (paired-pulse suppression) at IPI of 30 and 50 ms. The P2/P1 relation with behavior was not caused by the slight variations of P1 with behavior. In addition, paired-pulse facilitation of the population excitatory postsynaptic potentials (EPSP) was relatively small and not significantly dependent on behavior. Behavioral dependence of the paired-pulse responses was not generally found for IPI of 20 or 100 ms. It is concluded that paired-pulse facilitation at 30-50 ms IPI can best be explained by EPSP facilitation combined with a behaviorally dependent disinhibition.
Animals↗
Digital hand atlas and web-based bone age assessment: system design and implementation.
Bone age assessment is a procedure frequently performed in pediatric patients to evaluate their growth disorder. A simple method commonly used in bone age assessment is atlas matching by a radiological examination of a left-hand radiograph against a small reference set of Greulich-Pyle atlas patterns of normal standards. The method however can lead to significant deviation in age assessment, due to a variety of observers with different levels of training. The Greulich-Pyle atlas developed in the 1950s based on middle upper class white populations, is also not fully applicable for children of today, especially regarding the standard development in other racial groups. In this paper, we present our system design and initial implementation of a digital hand atlas and computer-aided diagnostic (CAD) system for Web-based bone age assessment. The CAD system is built on top of existing picture archiving and communication system (PACS), as well as recent advances in Internet technology. It consists of a hand atlas database, a CAD module and a Java-based Web user interface. The digital atlas is based on a large new set of clinically normal hand images of diverse ethnic groups. A relational image database system is used to organize hand images, their extracted quantitative features and patient data. The digital atlas removes the disadvantages of the currently out-of-date Greulich-Pyle atlas and allows the bone age assessment to be computerized. The Java-based Web user interface allows users to interact with the hand image database from browsers. Users can use a Web browser to push a clinical hand image to the CAD server for a bone age assessment. Quantitative features on the examined image, which reflect the skeletal maturity, are then extracted and compared with patterns from the atlas database to assess the bone age. The digital atlas method based on open system Internet technology provides an alternative to supplement or replace the traditional one for a quantitative, accurate and cost-effective assessment of bone age.
Adolescent↗