Phacoemulsification in a patient with torticollis.
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Aged↗
Biomedical subjects
C Liu
Publications and source records attributed to C Liu.
In vivo storage of XR family interspersed RNA in Xenopus oocytes.
Interspersed RNA is an abundant class of cytoplasmic poly(A)+ RNA which contains repetitive elements within mostly heterogeneous single copy sequences. In spite of its quantitative importance in oocytes or eggs (two-thirds of the total poly(A)+ RNA), very little is known about its synthesis, its interaction with other molecules, and its functional significance. Here, we analysed a prevalent family of interspersed RNA (XR family) during Xenopus oogenesis. We found that XR interspersed RNA, unlike extracted interspersed RNA, did not form RNA duplexes in vivo. In small oocytes (stage III), XR RNA interacted with proteins forming rapidly sedimenting ribonucleoprotein particles (RNPs) with a median sedimentation constant of 80S. However, towards the end of oogenesis (stage VI), these XR RNPs changed into smaller particles with a median sedimentation constant of 40S. By analysing the proteins associated with XR RNA sequence, we have identified a 42 kilodalton protein in small oocytes, which was replaced by a 45 kilodalton protein at stage V of oogenesis.
Animals↗
Degradation of Mersilene sutures.
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Animals↗
The carboxy termini of Sir4 and Rap1 affect Sir3 localization: evidence for a multicomponent complex required for yeast telomeric silencing.
The Silent Information Regulatory proteins, Sir3 and Sir4, and the telomeric repeat-binding protein RAP1 are required for the chromatin-mediated gene repression observed at yeast telomeric regions. All three proteins are localized by immunofluorescence staining to foci near the nuclear periphery suggesting a relationship between subnuclear localization and silencing. We present several lines of immunological and biochemical evidence that Sir3, Sir4, and RAP1 interact in intact yeast cells. First, immunolocalization of Sir3 to foci at the yeast nuclear periphery is lost in rap1 mutants carrying deletions for either the terminal 28 or 165 amino acids of RAP1. Second, the perinuclear localization of both Sir3 and RAP1 is disrupted by overproduction of the COOH terminus of Sir4. Third, overproduction of the Sir4 COOH terminus alters the solubility properties of both Sir3 and full-length Sir4. Finally, we demonstrate that RAP1 and Sir4 coprecipitate in immune complexes using either anti-RAP1 or anti-Sir4 antibodies. We propose that the integrity of a tertiary complex between Sir4, Sir3, and RAP1 is involved in both the maintenance of telomeric repression and the clustering of telomeres in foci near the nuclear periphery.
Cell Compartmentation↗
Intratracheal gene delivery with adenoviral vector induces elevated systemic IgG and mucosal IgA antibodies to adenovirus and beta-galactosidase.
One major concern about using adenoviral vectors for repetitive gene delivery to lung epithelial cells is the induction of an immune response to the vector, thus, impeding effective gene transduction. To assess the immune response to the adenoviral vector, repetitive intratracheal (i.t.) gene dosing was performed in CD-1 mice using the replication-deficient adenovirus 5 (Ade5) vector carrying the lacZ gene, and compared to the antibody responses induced by conventional intranasal (i.n.) and intraperitoneal (i.p.) routes of immunization. Kinetics of serum IgG, IgA, and IgM antibody responses to the adenoviral vector and to beta-galactosidase (beta-Gal) were evaluated. Two or three adenoviral vector doses given by i.t., i.n., or i.p. routes resulted in serum IgG titers in excess of 1:200,000, whereas serum IgM and IgA were moderately induced. Analysis of the predominant murine IgG subclass was determined to be IgG2b and IgG2a. To determine the localization of this antibody response, the ELISPOT assay was employed. Lymphocytes were isolated from the lung, the lower respiratory lymph nodes (LRLN), the nasal passages (NP), and the spleen. For i.t- and i.n.-administered mice, the highest IgA spot-forming cell (SFC) response to Ade5 and beta-Gal was located in the NP and in the lung. Both the lung and the LRLN showed elevated numbers of IgG SFCs (4- to 12-fold greater than splenic IgG SFC response) for Ade5 and beta-Gal. This evidence suggests that the lung and associated lymphoid tissues were the source for serum antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenoviridae↗
Species-specific activity of rat recombinant interleukin-1 beta.
We have constructed expression clones for mature rat interleukin-1 beta (IL-1 beta). Using these clones, rat recombinant IL-1 beta (rrIL-1 beta) was prepared and purified by a single-step cation-exchange chromatography method. In addition, synthetic rrIL-1 beta mRNA was transcribed and used to synthesize radiolabeled 35S-rrIL-1 beta for binding studies. The rrIL-1 beta produced was demonstrated to have IL-1 bioactivity in a mouse thymocyte proliferation assay, in which it could be blocked by inclusion of human recombinant IL-1 receptor antagonist (hrIL-1Ra). Similarly, rrIL-1 beta induced LIF mRNA expression in cultured rat sympathetic ganglia. In each case, the maximal dose of rrIL-1 beta was similar to that of human IL-1 beta. However, the peak response in rat tissue was twofold higher with rat IL-1 beta than with human IL-1 beta. The expression of rrIL-1 beta provides a useful tool for studying IL-1 receptors in rat, in which human and mouse IL-1 beta have been found to bind poorly. Species-specific activity of rat IL-1 beta may correlate with compensatory ionic properties of rat IL-1 receptor.
Amino Acid Sequence↗
Transgenic mice with reduced numbers of functional sperm receptors on their eggs reproduce normally.
To initiate fertilization in mice, free-swimming sperm bind to mZP3, an approximately 83-kDa glycoprotein present in the ovulated egg zona pellucida (ZP). mZP3 is located periodically along the filaments that constitute the ZP. Sperm recognize and bind to specific oligosaccharides linked to one or more of five Ser residues clustered in the carboxy-terminal one-third of the mZP3 polypeptide. When all five Ser residues are converted to nonhydroxy amino acids by site-directed mutagenesis of the mZP3 gene, an inactive form of mZP3, called mZP3[ser], is secreted by embryonal carcinoma cells stably transfected with the mutated gene. Here, seven independent transgenic mouse lines were established that harbor the mutated mZP3 gene. In all lines, the mutant gene is expressed by growing oocytes and mZP3[ser] is synthesized, secreted, and incorporated into the ZP. Purified mZP3[ser] prepared from ovaries of transgenic mice, like mZP3[ser] from transfected embryonal carcinoma cells, is inactive in sperm binding assays in vitro. On the other hand, the presence of mZP3[ser] in the ZP does not significantly affect either the binding of sperm to ovulated eggs in vitro or the reproduction of the mice, i.e., the transgenic mice are fertile, breed at normal intervals, and produce litters of normal sizes. These results indicate that the number of functional sperm receptors in the ZP can be reduced by more than 50% without adversely affecting fertilization of eggs in vivo.
Amino Acid Sequence↗
Prevention of osmotic injury to human spermatozoa during addition and removal of glycerol.
Use of a cryoprotective agent is indispensable to prevent injury to human spermatozoa during the cryopreservation process. However, addition of cryoprotective agents to spermatozoa before cooling and their removal after warming may create severe osmotic stress for the cells, resulting in injury. The objective of this study was to test the hypothesis that the degree (or magnitude) of human sperm volume excursion can be used as an independent indicator to evaluate and predict possible osmotic injury to spermatozoa during the addition and removal of cryoprotective agents. Glycerol was used as a model cryoprotective agent in the present study. To test this hypothesis, first the tolerance limits of spermatozoa to swelling in hypo-osmotic solutions (iso-osmotic medium diluted with water) and to shrinkage in hyperosmotic solutions (iso-osmotic medium with sucrose) were determined. Sperm plasma membrane integrity was measured by fluorescent staining, and sperm motility was assessed by computer-assisted semen analysis before, during and after the anisosomotic exposure. The result indicate firstly that motility was much more sensitive to anisosmotic conditions than membrane integrity, and secondly that motility was substantially more sensitive to hypotonic than to hypertonic conditions. Based on the experimental data, osmotic injury as a function of sperm volume excursion (swelling or shrinking) was determined. The second step, using these sperm volume excursion limits and previously measured glycerol and water permeability coefficients of human spermatozoa, was to predict, by computer simulation, the cell osmotic injury caused by different procedures for the addition and removal of glycerol. The predicted sperm injury was confirmed by experiment. Based on this study, an analytical methodology has been developed for predicting optimal protocols to reduce osmotic injury associated with the addition and removal of hypertonic concentrations of glycerol in human spermatozoa.
Buffers↗
High water permeability of human spermatozoa is mercury-resistant and not mediated by CHIP28.
A novel integral membrane protein with an apparent molecular mass of 28 kDa (CHIP28) was first isolated from human erythrocytes and is now recognized as a water channel protein. The expression of this protein has been found in several other cell types that all require high water permeability for their functions. Recent studies have shown that the water permeability (Lp) of human spermatozoa is among the highest reported for mammalian cells. Together with the low activation energy of human spermatozoa for Lp, this suggests that CHIP28 water channel may be present in the plasma membrane of human spermatozoa. However, our current studies do not support this hypothesis. Results from Western blot analysis on human sperm plasma membrane proteins, performed through use of an antibody against human erythrocyte CHIP28 protein, indicated that human spermatozoa do not express CHIP28 protein on their cell surface (n = 10). Consistent with the Western blot finding, mercuric chloride (HgCl2), a known water channel blocker, failed to reduce the osmotic water permeability of human spermatozoa. The calculated Lp values were 1.30 +/- 0.29 micron/min/atm (n = 16; mean +/- SEM) for the control group and 1.31 +/- 0.29 (n = 9; mean +/- SEM), 1.04 +/- 0.27 (n = 11; mean +/- SEM), and 1.34 +/- 0.19 (n = 6; mean +/- SEM), respectively, for the 10 microM, 30 microM, and 50 microM HgCl2-treated groups. These Lp values are not different (p > 0.05). In contrast, the same concentration of HgCl2 significantly blocked the osmotic water transport across the membrane of human erythrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
Aquaporin 1↗
Comparison of a rapid nonisotopic polymerase chain reaction assay with four commonly used methods for the early diagnosis of human immunodeficiency virus type 1 infection in neonates and children.
To initiate antiretroviral therapy and prophylaxis for Pneumocystis carinii pneumonia, it is important to identify human immunodeficiency virus (HIV-1)-infected infants as soon after birth as possible. This study was undertaken to evaluate a novel 5-hour nonisotopic (NI) polymerase chain reaction (PCR) assay (Amplicor PCR; Roche Molecular Systems) and four other commonly used HIV-1 diagnostic tests including culture, oligonucleotide hybridization PCR, p24 antigen and immune complex-dissociated (ICD) p24 antigen tests and to determine the optimal age at which to perform these tests for the early and rapid diagnosis of HIV-1 in infants and children. We prospectively evaluated 225 infants and children, including 114 neonates, for HIV-1 infection. HIV-1 infection was defined as 2 positive HIV cultures. Of the 225 infants and children, 57 were infected, 138 were uninfected and 30 were of unknown (Centers for Disease Control and Prevention Classification P0) status. The sensitivity of NI PCR was 60% in cord blood, 40% at 0 to 2 days, 67 to 80% in the neonate (3 to 30 days) and 95 to 100% after 1 month of age. NI PCR was as sensitive as oligonucleotide hybridization PCR, culture, p24 antigen and ICD p24 antigen in the first 2 months of life and was more sensitive than p24 antigen or ICD p24 antigen thereafter. Specificity was 94% for cord blood and 99 to 100% for all age groups. The majority of HIV-1-infected newborns can be identified with NI PCR if testing is performed at birth and again between the third and fourth weeks of life. For older infants and children 2 NI PCR tests can correctly diagnose 98.5% of infected and uninfected infants and children. NI PCR of umbilical cord blood might also be useful as an initial screening test to identify infants who may be infected with HIV-1.
AIDS Serodiagnosis↗
Influenza type A virus neuraminidase does not play a role in viral entry, replication, assembly, or budding.
We have used a neuraminidase-deficient influenza virus, NWS-Mvi, which was selected by supplying bacterial neuraminidase in the medium (C. Liu and G. M. Air, Virology 194:403-407, 1993), to define the role of neuraminidase in influenza virus replication. Electron microscopy showed that virions of the NWS-Mvi mutant assembled normally and formed large aggregates associated with cell surfaces. The NWS-Mvi virus grown in the absence of neuraminidase was able to carry out a second round of replication in MDCK cells without added neuraminidase, indicating that the virus particles contained in these aggregates were infectious. Aggregates of virus were also found in cytoplasmic vacuoles. When virus-infected cells were incubated in the presence of ferritin, such aggregates were found to be labeled with ferritin, indicating that they are derived from uptake at the cell surface. When the neuraminidase-deficient virus was administered intranasally to C57BL/6 mice, low titers of virus were recovered from the lungs and major histocompatibility complex class I-restricted cytotoxic T cells were generated: evidence that cells were infected in vivo. In C57BL/6 nu/nu mice, the low level of virus persisted for at least 28 days but never increased. These results suggest that neuraminidase is not required for influenza virus entry, replication, or assembly in cell culture or in mice.
Animals↗
CRF2 alpha and CRF2 beta receptor mRNAs are differentially distributed between the rat central nervous system and peripheral tissues.
We have recently described the cloning and characterization of a novel corticotropin-releasing factor receptor subtype (CRF2) from rat brain that exists in two alternatively spliced forms, CRF2 alpha and CRF2 beta. These forms differ in their N-terminal coding sequence which results in the production of two distinct receptors of 411 and 431 amino acids, respectively. To assess whether these two forms might represent distinct targets for CRF action, RNase protection and in situ hybridization studies were performed using specific N-terminal cRNA probes. The results showed a differential distribution of the mRNAs for these two receptor forms in the rat. The mRNA for CRF2 alpha is found almost exclusively in the brain, particularly in the hypothalamus, lateral septum, and olfactory bulb, whereas the mRNA for CRF2 beta appears to be both in the brain and in the periphery, with the greatest abundance in the heart and skeletal muscle. Thus, the data suggest that these alternatively spliced forms of the CRF2 receptor may represent functionally distinct CRF receptors. In addition, it highlights the importance of probe specificity for in situ hybridization studies.
Animals↗
Large-scale spraying of bednets to control mosquito vectors and malaria in Sichuan, China.
Since 1987, up to 2.42 million bednets owned by rural householders in over 40 counties in seven prefectures of Sichuan Province, China, have been sprayed annually with deltamethrin at a dose of about 10 mg/m2. Data for the years 1987-89 indicate that there were marked reductions in the biting populations and survival of the two vector species Anopheles anthropophagus and A. sinensis. Extensive tests in 1992 in areas where bednet spraying had been carried out for 5 years showed that mortality was 100% with the WHO-recommended discriminating dose of deltamethrin, i.e., there was no indication of resistance. Malaria data obtained by passive surveillance of reported cases, mass blood surveys of schoolchildren, and active surveillance of reported blood slides from fever cases all indicated marked reductions after introduction of the net spraying. In contrast, in the control areas, where the nets were not treated, the situation remained static or deteriorated slightly.
Animals↗
[Clinical analysis of iatrogenic pseudoaneurysms].
The surgical management of 9 patients with false aneurysms resulting from iatrogenic injury was reviewed. The principal symptoms were local pain in 8 patients, neuralgia syndrome in 3, and rupture in 2. In the series, swelling or pulsatile mass was present in 7 patients. Only 5 patients were noted to have an artery bruit at the time of examination. Of these patients, 6 were diagnosed clearly before operation and all of the pseudoaneurysms were confirmed surgically. Surgical treatment was carries out in 8 patients including emergency operation in 3. Postoperative complications were rather high (25%), but fortunately, there was no operative mortality in this series. The etiological diagnostic method and the principles of surgical management were discussed.
Adolescent↗
[Current malaria stratification in China].
During the past 30 years since 1958 when malaria stratification was first made, a great change in malaria situation has occurred. The original stratification can not represent the current status of malaria distribution. Therefore, it needs to be redivided so as to provide basis for future malaria control work. Taking species of mosquito vector and malaria incidence as the main indices and making reference to the natural geographical division, the current malaria endemic area in China can be divided into four regions, i.e. (1) Western region: it is mostly a natural non-endemic area, except some limited areas with sporadic cases in Xinjiang Autonomous Region; (2) Northern region: the whole north-eastern and partial northern China belong to the areas where malaria has been basically eliminated; but sporadic occurrence still exist in most part of the northern China; (3) Central region: it is mostly a hypo-endemic area, only a small part has meso-endemicity; (4) Southern region: nearly 50% has meso-endemicity and the other 50% has hypo-endemicity. The demarcation line of natural non-endemic areas and the areas where malaria has been basically eliminated has been defined.
Animals↗
[Detection of thyroid stimulating antibodies and TSH binding inhibitor immunoglobulins in patients with thyroid diseases and its clinical applications].
Thyroid stimulating antibodies (TSAb) and TSH binding inhibitor immunoglobulins (TBII) were assessed in patients with thyroid diseases. The activity of TSAb and TBII was significantly higher in patients with untreated Graves' disease (GD) as compared with that in patients with remitted GD and Hashimoto's thyroiditis, while the latter two groups had higher TSAb and TBII activity than patients with thyroid adenoma or control subjects. Of 24 patients with untreated GD, TSAb and TBII were detected in 22 and 19 respectively. The positive rates of TSAb and TBII in patients with remitted GD or Hashimoto's thyroiditis were 0.48 and 0.44 or 0.231 and 0.615. Both TSAb and TBII were negative in patients with thyroid adenoma or controls. No statistical correlation was found between TSAb and TBII activity, suggesting the coexistence of heterogeneous populations of TSH receptor antibodies.
Adenoma↗
[Effects of Chinese ginseng root and stem-leaf saponins on learning, memory and biogenic monoamines of brain in rats].
The present investigation has shown that Ginseng root saponins (ig, 50mg/kg x 7d) facilitate the learning and memory of normal male Wistar rats, while the effect of Ginseng stem-leaf saponins (ig, 50mg/kg x 7d) on antielectrconvulsive shock-induced impairment of memory consolidation in rats is more intensive than that of root saponins. Both Ginseng root and stem-leaf saponins can significantly raise the levels of biogenic monoamines in normal rat's brain.
Animals↗
[The significance of dynamic change of plasma endothelin level in epidemic hemorrhagic fever].
One hundred and twenty nine hospitalized cases of epidemic hemorrhagic fever (EHF) diagnosed and classified according to the protocol of prevention and treatment of this disease approved by the Ministry of Health in 1987 were studied to ascertain the role of endothelin (ET) in the etiology. 30 healthy adult subjects residing in the same area served as control. Blood samples were collected and plasma ET level was measured with radioimmunoassay and its dynamic change noted. It is shown that plasma ET level of the EHF patients was higher in febrile, hypotensive or shock, oliguric and transitional stages than that of controls. However, the level returned to normal in polyuric stage. Plasma ET level was also highly positively correlated with that of Tamm-Horsfall protein (THP) and beta 2 microglobulin. The higher the level of plasma ET, the poorer the ontcome. It is suggested that ET plays an important role in the epidemiology of EHF and monitoring of plasma ET level will be of help not only in predicting the prognosis, but also in guiding the clinical therapy.
Adolescent↗