Emerging role of Mcl-1 in actively counteracting BH3-only proteins in apoptosis.
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Animals↗
Biomedical subjects
J Zhuang
Publications and source records attributed to J Zhuang.
The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer.
BACKGROUND: Cutaneous hyperpigmentation occurs in multiple conditions. In addition, many Asian women desire a lighter skin colour. Thus, there is a need for the development of skin lightening agents. Niacinamide is a possible candidate. OBJECTIVES: To investigate the effects of niacinamide on melanogenesis in vitro and on facial hyperpigmentation and skin colour in vivo in Japanese women. METHODS: Melanin production was measured in a purified mushroom tyrosinase assay, cultured melanocytes, a keratinocyte/melanocyte coculture model, and a pigmented reconstructed epidermis (PREP) model. The clinical trials included 18 subjects with hyperpigmentation who used 5% niacinamide moisturizer and vehicle moisturizer in a paired design, and 120 subjects with facial tanning who were assigned to two of three treatments: vehicle, sunscreen and 2% niacinamide + sunscreen. Changes in facial hyperpigmentation and skin colour were objectively quantified by computer analysis and visual grading of high-resolution digital images of the face. RESULTS: Niacinamide had no effect on the catalytic activity of mushroom tyrosinase or on melanogenesis in cultured melanocytes. However, niacinamide gave 35-68% inhibition of melanosome transfer in the coculture model and reduced cutaneous pigmentation in the PREP model. In the clinical studies, niacinamide significantly decreased hyperpigmentation and increased skin lightness compared with vehicle alone after 4 weeks of use. CONCLUSIONS: The data suggest niacinamide is an effective skin lightening compound that works by inhibiting melanosome transfer from melanocytes to keratinocytes.
Adolescent↗
Oxygen transport in tibetan women during pregnancy at 3,658 m.
High-altitude reduces infant birth weight as a result of intrauterine growth restriction (IUGR) and is associated with increased neonatal mortality. We hypothesized that babies born to Tibetan compared to Han (Chinese) high-altitude residents were protected from IUGR as the result of increased maternal O(2) transport due, in turn, to increased uterine artery (UA) blood flow. We studied 68 nonpregnant or pregnant Tibetan or Han residents of Lhasa, Tibet Autonomous Region, China (3,658 m). The pregnant women had higher hypoxic ventilatory responses (HVR A) and resting ventilations (V(E)) than their nonpregnant counterparts (Tib HVR = 134 +/- 16 (SEM) vs. 30 +/- 8, Han HVR = 134 +/- 16 vs. 66 +/- 18 A units; Tib V(E) = 11.8 +/- 0.3 vs. 10.1 +/- 0.5, Han V(E) = 10.7 +/- 0.5 vs. 9.4 +/- 0.5 l BTPS/min; all P < 0.05). Pregnancy did not change hemoglobin concentration in the Han but lowered values more than 2 g/dl in the Tibetans, serving to reduce arterial O(2) content below Han values (15.4 +/- 0.3 vs. 17.4 +/- 0.5 ml O(2)/100 ml whole blood, P < 0.05). Compared with the Han, the pregnant Tibetans had higher UA blood flow velocity (58.5 +/- 2.9 vs. 49.1 +/- 3.2, P < 0. 05) and distributed a higher portion of common iliac (CI) blood flow to the UA (4.8 +/- 0.4 vs. 3.3 +/- 0.3, P < 0.05). Birth weights averaged 635 g greater in the Tibetan than Han high-altitude residents (3,280 +/- 78 vs. 2,645 +/- 96 g, P < 0.01), or 694 g more when adjusted for maternal age, parity, height, and near-term body weight. Heavier birth weight babies were born to women with higher V(E) (r = 0.62, P < 0.01) and greater distribution of CI blood flow to the UA (r = 0.42, P < 0.05). We conclude that increased UA blood flow, and not higher arterial O(2) content, permits Tibetan women to increase uteroplacental O(2) delivery and protect their infants from altitude-associated IUGR.
Adaptation, Physiological↗
[A multiple-channel system for synchronous acquisition and analysis of neural electrophysiological signals].
The technique for synchronous electrophysiological recording from multiple single cells has been widely applied, but there is still a shortage of suitable data acquisition and analysis systems to fit electrophysiological equipment made in China or Japan. Recently we have developed an acquisition and analysis system for multiple-channel electrophysiological recording. In this paper, we present the pivotal technique of the system and some examples of applications.
Animals↗
[A study of millimeter wave's clinical and immunological effects on oral lichen planus patients].
OBJECTIVE: The aim of this study is to observe clinical effects of the millimeter wave on oral lichen planus (OLP) and its immune mechanisms. METHODS: 30 patients with OLP were randomized into the millimeter wave group and the control group. 15 patients in the millimeter wave group were treated with millimeter wave (7.1 mm, 43 GHz, 10 mW/cm2) radiation, while the other 15 patients in the control group were just given soothing treatment. Either before or after the therapy procedure, the clinical manifestations and the T-cell sub-grouping in the peripheral circulation of each patient were double-blindly evaluated. RESULTS: The pain-soothing effect in the patients treated with millimeter wave was much more obvious than that of the control group (P < 0.01). The peripheral blood CD8+ percent of millimeter wave group decreased greatly (P < 0.05), while no obvious CD8+ change was observed in the control group (P > 0.05). The millimeter wave group's CD4+/CD8+ improvement was also much more obvious than that of the control group (P < 0.05), and its CD4+/CD8+ ratio was completely recovered to the normal level. CONCLUSION: Millimeter wave can effectively relieve OLP patients' pain, and can regulate OLP patients' cellular immune condition. Millimeter wave might provide a new treatment method for OLP.
Adult↗
[Comprehensive quality appraisal of "maidong"].
According to the contents of 14 kinds of constituents, 6 samples of Maidong from various habitats were comprehensively appraised by the weighted method with factor analysis and fuzzy mathematic method. The results showed that certified Maidong (Ophiopogon japonicus) was superior to its substitute Shanmaidong(Liriope spp.), and the sample from Xiaoshan county was the best in 3 samples of certified goods. Being consistent with the result of the traditional appraisal, the method used in this paper may provide a new means for appraising traditional medicinal materials.
Drugs, Chinese Herbal↗
[Calculation of spectroscopic parameters of Ho3+ in Ho:YVO4 crystal].
The intensity parameters omega lambda of Ho3+ in Ho:YVO4 crystal were calculated with J-O theory according to the absorption spectrum. Based on these omega lambda values, the oscillator strength of excited energy state, spontaneous radiation rate, branching ratio and integrated emission cross section were estimated. A discussion on potentiality of application in the infrared laser material is given.
Chemical Phenomena↗
[Study on the reaction between 3-amino-6-dimethylamino-2-methlphenazine hydrochloride and deoxyribonucleic acid].
The interaction of deoxyribonucleic acid (DNA) and 3-amino-6-dimethylamino-2-methlphenazine hydrochloride (ZR) was investigated by UV spectrophotometric method in solution (pH 7.4). When DNA was added into ZR solution, the red color was observed, which indicated formation of the DNA-ZR complex. The maximum absorption of the complex was 520 nm with the apparent molar absorptivity of epsilon = 1.5 x 10(6) mol-1.L.cm-1. The maximum absorption of the complex was shifted 70 nm than with ZR. The maximum binding number is n = 303. The basic reaction conditions were investigated. It is found that sodium chloride concentration of the solution has significant effect on the sensitivity of DNA-ZR complex. The Scatchard model is appropriate in the treatment of data obtained here.
Chelating Agents↗
Synthesis of SnSe in various alkaline media under mild conditions.
The synthesis of SnSe was systematically investigated in various alkaline media and at various temperatures with SnCl2.2H2O and selenium as source materials. The basicity of the alkaline media and the reaction temperature are two key factors considered in our process. The synthesis of SnSe in sodium hydroxide solution and aqueous ammonia is limited to a narrow temperature range, while the synthesis in hydrazine hydrate and ethylenediamine proceeds over a wider range. The final products were characterized by X-ray diffraction pattern (XRD), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). TEM results showed a variation of crystal morphology of SnSe obtained in different media. Two simple chemical mechanisms for the formation of SnSe are presented.
Journal Article↗
Synthetic strands of neonatal mouse cardiac myocytes: structural and electrophysiological properties.
The aim of the present study was to morphologically and electrically characterize synthetic strands of mouse ventricular myocytes. Linear strands of mouse ventricular myocytes with widths of 34.7+/-4.4 microm (W(1)), 57.9+/-2.5 microm (W(2)), and 86.4+/-3. 6 microm (W(3)) and a length of 10 mm were produced on glass coverslips with a photolithographic technique. Action potentials (APs) were measured from individual cells within the strands with cell-attached microelectrodes. Impulse propagation and AP upstrokes were measured with multisite optical mapping (RH237). Immunostaining was performed to assess cell-cell connections and myofibril arrangement with polyclonal antisera against connexin43 and N-cadherins and monoclonal antibodies against cardiac myosin. Light microscopy and myosin staining showed dense growth of well-developed elongated myocytes with lengths of 34.2+/-4.2 microm (W(1)), 36. 9+/-5.8 microm (W(2)), and 43.7+/-6.9 microm (W(3)), and length/width ratios of 3.9+/-0.2. Gap junctions were distributed around the cell borders (3 to 4 junctions/microm(2) cell area). Each cell was connected by gap junctions to 6.5+/-1.1 neighboring cells. AP duration shortened with time in culture (action potential duration at 50% repolarization: day 4, 103+/-34 ms; day 8, 16+/-3 ms; P:<0.01). Minimum diastolic potential and AP amplitude were 71+/-5 and 97.2+/-7.6 mV, respectively. Conduction velocity and the maximum dV/dt of the AP upstroke were 43.9+/-13.6 cm/s and 196+/-67 V/s, respectively. Thus, neonatal ventricular mouse myocytes can be grown in continuous synthetic strands. Gap junction distribution is similar to the neonatal pattern observed in the hearts of larger mammals. Conduction velocity is in the range observed in adult mice and in the higher range for mammalian species probably due to the higher dV/dt(max). This technique will permit the study of propagation, AP, and structure-function relations at cellular resolution in genetically modified mice.
Action Potentials↗
Pulsatile stretch remodels cell-to-cell communication in cultured myocytes.
Mechanical stretch is thought to play an important role in remodeling atrial and ventricular myocardium and may produce substrates that promote arrhythmogenesis. In the present work, neonatal rat ventricular myocytes were cultured for 4 days as confluent monolayers on thin silicone membranes and then subjected to linear pulsatile stretch for up to 6 hours. Action potential upstrokes and propagation velocity (theta) were measured with multisite optical recording of transmembrane voltage of the cells stained with the voltage-sensitive dye RH237. Expression of the gap junction protein connexin43 (Cx43) and the fascia adherens junction protein N-cadherin was measured immunohistochemically in the same preparations. Pulsatile stretch caused dramatic upregulation of intercellular junction proteins after only 1 hour and a further increase after 6 hours (Cx43 signal increased from 0.73 to 1.86 and 2.02% cell area, and N-cadherin signal increased from 1.21 to 2.11 and 2.74% cell area after 1 and 6 hours, respectively). This was paralleled by an increase in theta from 27 to 35 cm/s after 1 hour and 37 cm/s after 6 hours. No significant change in the upstroke velocity of the action potential or cell size was observed. Increased theta and protein expression were not reversible after 24 hours of relaxation. Nonpulsatile (static) stretch produced qualitatively similar but significantly smaller changes than pulsatile stretch. Thus, pulsatile linear stretch in vitro causes marked upregulation of proteins that form electrical and mechanical junctions, as well as a concomitant increase in propagation velocity. These changes may contribute to arrhythmogenesis in myocardium exposed to acute stretch.
Action Potentials↗
Asymmetry of brain functional activation: fMRI study under language and music stimulation.
OBJECTIVE: To determine the asymmetry of the human brain functional activation. METHODS: With the help of GE Signa Horizon MRI system, 14 cases of right-handed volunteers were examined and the blood oxygenation level dependent method was used. The T1-weighted images were obtained with spin echo pulse sequence and the functional imaging (T2*-weighted) was performed using a single shot echo planar imaging pulse sequence. Data analysis was done with Sun Sparc Workstation and by the method of student t test or correlation analysis. RESULTS: Most of activation areas were in the left hemisphere under language stimulation, while they were in the right side under music stimulation. Besides, a few brain areas in the contralateral cerebral cortex were also activated under both stimulations. CONCLUSION: The present study supported the hypothesis of the asymmetry of brain functional activation and many brain areas of the cerebral cortex as well as both hemispheres worked in coordination. In addition, it also proved that fMRI is a feasible method in the study of human brain in vivo.
Acoustic Stimulation↗
[Adjustable interatrial communication in management of severe congenital heart disease].
OBJECTIVE: To assess the use of adjustable interatrial communication in patient with severe congenital heart disease undergoing open heart surgery. METHODS: From February 1998 to June 1999, 13 patients with severe and complex congenital heart disease underwent open heart surgery. Seven patients underwent total cavopulmonary connection, five patients repair of Ebstein's anomaly, and one patient right atrial-pulmonary connection. Adjustable interatrial communication was made in all patients. Four patients had the communication closed at the time of operation, 4 patients had the communication opened at the time of operation, and 5 patients had the communication adjusted and closed postoperatively. RESULTS: All patients had a smooth postoperative process. There were no postoperative death and no severe postoperative complications. CONCLUSION: Adjustable interatrial communication for the patients undergoing modified Fontan procedure or correction of Ebstein's anomaly may be advantageous.
Adolescent↗
[Construction of plasmids expressing hepatitis E virus antigen fragments and their combinations].
OBJECTIVE: Several different regions of the HEV antigen were expressed in Escherichia coli and their immunological characteristics were simply evaluated. METHODS: Three coding sequences of immunodominant antigenic regions in structural protein of the hepatitis E virus (ORF2.1: 6287-6403nt, ORF2.2: 6743-7126nt, ORF3: full length of ORF3) were amplified by RT-PCR from the fecal supernatants of macaques experimentally infected with HEV. These three fragments were inserted into the pThioHisC expression vector separately or fused in line by (Gly)n short arms. After identified by DNA sequence analysis, these six recombinant plasmids were transformed into Escherichia coli, and immunology characteristics of expressed antigen fragments were evaluated by Western blotting. RESULTS: All six genes were successfully expressed in Escherichia coli. Western blotting assay showed that the recombinant proteins specifically reacted with the serum antibody from hepatitis E patient in various degrees. CONCLUSION: Artificial antigen based on strung epitopes provides a promising strategy for detection and prevention of HEV infection.
Antigens, Viral↗
Purification and electron microscopic characterization of the membrane subunit (IICB(Glc)) of the Escherichia coli glucose transporter.
The glucose transporter of the bacterial phosphotransferase system mediates sugar transport across the cytoplasmic membrane concomitant with sugar phosphorylation. It consists of a cytoplasmic subunit IIA(Glc) and the transmembrane subunit IICB(Glc). IICB(Glc) was purified to homogeneity by urea/alkali washing of membranes and nickel-chelate affinity chromatography. About 1.5 mg highly pure IICB(Glc) representing 77% of the total activity present in the membranes was obtained from 8g (wet weight) of cells. IICB(Glc) was reconstituted into lipid bilayers by temperature-controlled dialysis to yield small 2D crystals and by a rapid detergent-dilution procedure to yield densely packed vesicles. Electron microscopy and digital image processing of the negatively stained 2D crystals revealed a trigonal lattice with a unit cell size of a = b = 14.5 nm. The unit cell morphology exhibited three dimers of IICB(Glc) surrounding the threefold symmetry center. Single particle analysis of IICB(Glc) in proteoliposomes obtained by detergent dialysis also showed predominantly dimeric structures.
Chromatography, Affinity↗
Distinct caspase cascades are initiated in receptor-mediated and chemical-induced apoptosis.
Release of cytochrome c is important in many forms of apoptosis. Recent studies of CD95 (Fas/APO-1)-induced apoptosis have implicated caspase-8 cleavage of Bid, a BH3 domain-containing proapoptotic member of the Bcl-2 family, in this release. We now demonstrate that both receptor-induced (CD95 and tumor necrosis factor) and chemical-induced apoptosis result in a similar time-dependent activation of caspases-3, -7, -8, and -9 in Jurkat T cells and human leukemic U937 cells. In receptor-mediated apoptosis, the caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp fluoromethyl ketone (Z-VAD. FMK), inhibits apoptosis prior to commitment to cell death by inhibiting the upstream activator caspase-8, cleavage of Bid, release of mitochondrial cytochrome c, processing of effector caspases, loss of mitochondrial membrane potential, and externalization of phosphatidylserine. However, Z-VAD.FMK inhibits chemical-induced apoptosis at a stage after commitment to cell death by inhibiting the initiator caspase-9 and the resultant postmitochondrial activation of effector caspases. Cleavage of Bid but not release of cytochrome c is blocked by Z-VAD.FMK demonstrating that in chemical-induced apoptosis cytochrome c release is caspase-independent and is not mediated by activation of Bid. We propose that caspases form an integral part of the cell death-inducing mechanism in receptor-mediated apoptosis, whereas in chemical-induced apoptosis they act solely as executioners of apoptosis.
Amino Acid Chloromethyl Ketones↗
Two-dimensional crystallization of Escherichia coli lactose permease.
A chimeric protein consisting of lactose permease with cytochrome b562 in the middle cytoplasmic loop and six His residues at the C terminus (LacY/L6cytb562/417H6 or "red permease") was overexpressed in Escherichia coli and isolated by nickel affinity chromatography after solubilization with dodecyl-beta,d-maltopyranoside. Red permease was then reconstituted in the presence of phospholipids, yielding densely packed vesicles and well-ordered two-dimensional (2D) crystals as shown by electron microscopy of negatively stained specimens. Single-particle analysis of 16 383 protein particles in densely packed vesicles reveals a 5.4-nm-long trapeziform protein of 4.1 to 5.1 nm width, with a central stain-filled indentation. Depending on reconstitution conditions, trigonal and rectangular crystallographic packing arrangements of these elongated particles assembled into trimers are observed. The best ordered 2D crystals exhibit a rectangular unit cell, of dimensions a = 9.9 nm, b = 17.4 nm, that houses two trimeric complexes. Projection maps calculated to a resolution of 2 nm show that these crystals consist of two layers.
Carrier Proteins↗
Redistribution of cytochrome c precedes the caspase-dependent formation of ultracondensed mitochondria, with a reduced inner membrane potential, in apoptotic monocytes.
Apoptosis was induced in human monocytic THP.1 cells by the use of chemicals with disparate mechanisms of action. Apoptotic cells were characterized by a reduced inner mitochondrial membrane potential, increased cytosolic cytochrome c, ultracondensed mitochondria, condensed chromatin, cytoplasmic inclusions of beta-actin, and fragmentation of the Golgi apparatus. All of these changes, except the release of cytochrome c, were prevented by caspase inhibition. Cells were separated into two populations, with either normal or low inner mitochondrial membrane potential, using fluorescence-activated cell sorting. Ultracondensed mitochondria were observed only in the cells with low inner mitochondrial membrane potential, whereas noncondensed mitochondria were found in the cells with a normal inner mitochondrial membrane potential. We have demonstrated a sequence of related biochemical and ultrastructural changes, commencing with the release of mitochondrial cytochrome c, followed by activation of caspases and a reduction of inner mitochondrial membrane potential. These changes involved the formation of ultracondensed but not swollen mitochondria. Thus the release of mitochondrial cytochrome c was not the result of the mitochondrial permeability transition, reduction of inner mitochondrial membrane potential, or rupture of the outer mitochondrial membrane. Discontinuities in the outer membrane of ultracondensed mitochondria may, however, facilitate the further release of caspase-activating proteins, thereby amplifying the apoptotic process.
Actins↗