Biomedical subjects

Y Han

Publications and source records attributed to Y Han.

At least 199 records · Page 11Linked to original sources

PubMed1998

HIV-1/simian immunodeficiency virus infection of human and nonhuman primate lymphocytes results in the migration of CD2+ T cells into the intestine of engrafted SCID mice.

Increased lymphocytic infiltration of intestinal tissues has been observed in patients infected with HIV-1 and in SIV-infected rhesus macaques. To determine whether HIV-1 and SIV infections influence the homing of human and nonhuman primate PBMC to intestinal tissues, we engrafted SCID mice with human or nonhuman primate PBMC and infected them with either cell-free or cell-associated HIV-1 or SIV. In mice that received both PBMC and virus, human or nonhuman primate CD2+ T cells were found in intestinal tissues, primarily in the intraepithelial lymphocyte compartment and lamina propria. Immunomagnetic sorting revealed that these cells were derived from the CD4+ population. Using gag-specific primers, PCR analysis of these tissues detected the presence of HIV-1 proviral DNA. However, in SCID mice that were engrafted with either human or nonhuman primate PBMC and no HIV-1 or SIV, CD2+ T cells were not detected in intestinal tissues. These results indicate that HIV-1 and SIV can modulate the migratory properties of human and nonhuman primate T cells in the SCID mouse model.

Animals↗

PubMed1998

The effect of superoxide dismutase on the recovery of human bone marrow hemopoietic stem cells stored at 4 degreesC.

The effect of superoxide dismutase (SOD) on the recovery of human hemopoietic stem cells stored at 4 degreesC has been studied. Human bone marrow cells from cancer patients without hemopoietic diseases were stored at 4 degreesC for 1-7 days in RPMI 1640 medium containing 10% human AB serum with or without 6 U/ml of SOD. The recovery of colony-forming units of the following types were counted: granulocyte and macrophage type; megakaryocyte type; mixed granulocyte, erythrocyte, megakaryocyte, and macrophage type; and burst-forming units of erythrocytic type. The SOD groups recovered, respectively, 5.6, 5.3, 4.6, and 4.4 times as many colonies as the control group. This study demonstrates that the addition of SOD to hypothermic storage media may increase the recovery of hemopoietic stem cells.

Cell Survival↗

PubMed1998

Electric field-induced functional reductions in the K+ channels mainly resulted from supramembrane potential-mediated electroconformational changes.

The goal of this study is to distinguish the supramembrane potential difference-induced electroconformational changes from the huge transmembrane current-induced thermal damages in the delayed rectifier K+ channels. A double Vaseline-gap voltage clamp was used to deliver shock pulses and to monitor the channel currents. Three pairs of 4-ms shock pulses were used to mimic the electric shock by a power-line frequency electric field. Each pair consists of two pulses with the same magnitude, starting from 350 to 500 mV, but with opposite polarities. The shock pulse-generated transmembrane ion flux and the responding electric energy, the Joule heating, consumed in the cell membrane, as well as the effects on the K+ channel currents, were obtained. Results showed that huge transmembrane currents are not necessary to cause damages in the K+ channel proteins. In contrast, reductions in the K+ channel currents are directly related to the field-induced supramembrane potential differences. By a comparison with the shock field-induced Joule heating effects on cell membranes, the field-induced supramembrane potential difference plays a dominant role in damaging the K+ channels, resulting in electroconformational changes in the membrane proteins. In contrast, the shock field-induced huge transmembrane currents, therefore the thermal effects, play a secondary, trivial role.

Animals↗

PubMed1998

Muscle spindles are concentrated in the superior vocalis subcompartment of the human thyroarytenoid muscle.

It is hypothesized that different parts of the thyroarytenoid muscle (TA) are functionally specialized. Specifically, the TA is divided into a lateral muscularis compartment and a medial vocalis compartment. This study examined the distribution of muscle spindles throughout the human TA as an indicator of these functional differences. Histological cross-sections from the anterior, middle, and posterior regions of five human membranous vocal folds were examined for the number and location of muscle spindles. There was an average of 6.1 muscle spindles in sections from each region with no significant variation between the different regions (p < .05). However, in sections from all three regions, the muscle spindles were always found to be concentrated in the superior medial quadrant of the TA (mean 85.9%, p < .01). The inferior medial, superior lateral, and inferior lateral quadrants of the TA contained 11.96%, 2.17%, and 0%, respectively, of the total muscle spindles. Within the superior medial quadrant, most of the muscle spindles were localized in the most superficial part of the muscle. The results of this study demonstrate that the majority of TA muscle spindles are concentrated in its superior medial quadrant, an area we have termed the superior vocalis subcompartment (SC). This finding suggests that the superior vocalis SC is functionally distinct from the remainder of the TA. It is hypothesized that tension in the superior vocalis SC can be controlled independently from the remainder of the TA, and this capability is used to effect the biomechanics of vocal fold vibration during phonation.

Humans↗

PubMed1998

Effects of neck muscle proprioceptive activation on the dynamics of monocularly driven horizontal vergence movements.

PURPOSE: The dynamics of accommodative vergence responses were studied to accommodative stimuli combined with the activation of neck muscle proprioception. METHODS: Accommodative stimulation was done with a LED bar. The stimuli were presented monocularly in a stepwise and a sinusoidal mode to either the dominant or the non-dominant eye with the other eye covered. The neck proprioceptors were activated by vibration on the neck muscles which turn the head horizontally. Eye movements were recorded with an infra-red reflection system in both eyes. RESULTS: Vibration of the neck muscles shortened the time constant of the accommodative vergence movement in the covered eye to square wave stimulation when the non-dominant eye was fixating the targets. The gain factor to sine wave stimulation was higher when the non-dominant eye was fixating. CONCLUSION: Extraretinal signals from neck proprioception influenced not only the static eye position, but also the dynamics of monocularly driven accommodative vergence movements, when the non-dominant eye was the viewing eye.

Accommodation, Ocular↗

PubMed1998

A vaccine and monoclonal antibodies that enhance mouse resistance to Candida albicans vaginal infection.

We previously reported that a vaccine composed of liposome-mannan complexes of Candida albicans (L-mann) stimulates mice to produce protective antibodies against disseminated candidiasis. An immunoglobulin M (IgM) monoclonal antibody (MAb), B6.1, specific for a beta-1,2-mannotriose in the complexes protects against the disease, whereas MAb B6 does not. In the present study, the vaccine and MAbs B6.1 and B6 were tested for the ability to protect against Candida vaginal infection, established by intravaginal (i.vg.) inoculation of yeast cells in mice maintained in pseudoestrus. Fungal CFU in each vagina was determined to assess the severity of infection. Mice vaccinated before infection developed about 62% fewer vaginal CFU than nonimmunized controls. Naive mice that received polyclonal antiserum (from vaccinated mice) i.vg. before infection had 60% fewer CFU than controls. The serum protective factor was stable at 56 degreesC, but C. albicans cells absorbed this factor. Mice given MAb B6.1 i.vg. after infection was established had fewer Candida CFU in vaginal tissue than control mice given buffer instead of antibody. MAbs B6.1 and B6 given intraperitoneally before infection protected mice, but MAbs preabsorbed with yeast cells did not. MAb B6.1 also protected against C. tropicalis vaginal infection, but MAb B6 did not. The protective activities of MAbs B6.1 and B6 appeared to be specific because an irrelevant IgM carbohydrate-specific MAb and an irrelevant IgG protein-specific MAb were not protective; also, MAb B6.1 did not affect development of vaginal chlamydial infection. These studies show that an appropriate antibody response, or administration of protective antibodies, can help the host to resist Candida vaginal infection.

Animals↗

PubMed1998

Contrasting roles of mannan-specific monoclonal immunoglobulin M antibodies in the activation of classical and alternative pathways by Candida albicans.

Polyclonal antimannan immunoglobulin G (IgG) activates the classical complement pathway and accelerates initiation of the alternative pathway by Canidida albicans. This dual role was assessed for two antimannan IgM monoclonal antibodies (MAbs). MAb B6.1 is specific for an epitope on the acid-labile portion of C. albicans phosphomannan; MAb B6 is specific for an epitope on the acid-stable region. Both MAbs were potent activators of the classical pathway but poor facilitators of alternative pathway initiation.

Antibodies, Monoclonal↗

PubMed1998

The major component of IkappaBalpha proteolysis occurs independently of the proteasome pathway in respiratory syncytial virus-infected pulmonary epithelial cells.

Previously we showed that infection of human type II airway epithelial (A549) cells with purified respiratory syncytial virus (pRSV) induced interleukin-8 transcription by a mechanism involving cytokine-inducible cytoplasmic-nuclear translocation of the RelA transcription factor. In unstimulated cells, RelA is tethered in the cytoplasm by association with the IkappaB inhibitor and can be released only following IkappaB degradation. In this study, we examined the spectrum of IkappaB isoform expression and kinetics of proteolysis of the isoforms in A549 cells following pRSV infection. In contrast to the rapid and robust activation of RelA DNA binding that peaked within 15 min of treatment produced by the prototypic activator tumor necrosis factor alpha (TNF-alpha), pRSV produced a weaker increase in RelA binding that began at 3 h and did not peak until 24 h after infection. A549 cells expressed the IkappaB inhibitory subunits IkappaBalpha, IkappaBbeta, and p105; however, following either stimulus, only the IkappaBalpha and IkappaBbeta steady-state levels declined in parallel with the increase in RelA DNA-binding activity. The >120-min half-life of IkappaBalpha in control cells was shortened to 5 min in TNF-alpha-stimulated cells and to 90 min in pRSV-infected cells. Although IkappaBalpha was resynthesized within 30 min following recombinant human TNFalpha treatment due to a robust 25-fold increase of IkappaBalpha mRNA expression (the RelA:IkappaBalpha positive feedback loop), following pRSV infection, there was no reaccumulation of IkappaBalpha protein, as infected cells produced only a 3-fold increase in IkappaBalpha mRNA at 24 h, indicating the RelA:IkappaBalpha positive feedback loop was insufficient to restore control IkappaBalpha levels. IkappaBalpha proteolysis induced by TNF-alpha occurred through the 26S proteasome, as both 26S proteasome activity and IkappaBalpha proteolysis were blocked by specific inhibitors lactacystin, MG-132, and ZLLF-CHO. Although total proteasome activity in 24-h pRSV-infected lysates increased twofold, its activity was >90% inhibited by the proteasome inhibitors; surprisingly, however, IkappaBalpha proteolysis was not. We conclude that RSV infection produces IkappaBalpha proteolysis through a mechanism primarily independent of the proteasome pathway.

Cell Line↗

PubMed1998

Human vocalis contains distinct superior and inferior subcompartments: possible candidates for the two masses of vocal fold vibration.

It is not understood how different parts of the thyroarytenoid muscle contribute to vocal fold vibration. This study investigated the medial part of the thyroarytenoid muscle, the vocalis compartment, for anatomic differences that might suggest functionally distinct areas. Twenty human vocal folds were frontally sectioned and stained with hematoxylin and eosin. A single section from the middle of each vocal fold was magnified, and the muscle fascicles of the most superficial 25% of the vocalis compartment were then examined. In all 20 specimens the vocalis compartment could be separated into 2 plainly distinct subcompartments: the inferior vocalis compartment was composed of a single large muscle fascicle that contained densely packed muscle fibers of similar size; the superior vocalis compartment was composed of multiple small fascicles in which the muscle fibers were loosely arranged and varied greatly in size. On average, the inferior vocalis subcompartment composed 60% of the medial surface of the thyroarytenoid muscle. The superior subcompartment composed the remaining 40% of the medial surface, but also continued past the vocal ligament to make up the superior surface of the thyroarytenoid muscle. It is concluded that 2 distinct entities make up the vocalis compartment of the thyroarytenoid muscle. Their anatomy is so markedly different it suggests that they may function independently. One possibility is that they reflect the 2 masses observed in the superior and inferior aspects of the vocal fold during vibration.

Humans↗

PubMed1998

Granuloma formation and in vitro macrophage activation in mice by mycoloyl glycolipids from Nocardia asteroides and related taxa.

Cord factor (trehalose 6,6'-dimycolate: TDM) is a well-known toxic glycolipid in Mycobacterium tuberculosis. We isolated various mycoloyl glycolipids from Nocardia asteroides 23,167 and related species which are closely related taxonomically to Mycobacterium. Since Nocardia is also an opportunistic pathogen co-infected with HIV, we examined in vivo granuloma formation and the in vitro macrophage activation in mice. We found that cord factor (TDM) and glucose monomycolate (GM) from Nocardia asteroides and Rhodococcus species with shorter chain mycolic acids also exhibited distinctive granuloma-forming activity in lungs, spleen and liver in mice and in vitro induction of prostaglandin E2 (PGE2) and interleukin 1 (IL-1) synthesis. We also found that mycoloyl glycolipids possessing trehalose or glucose as a carbohydrate moiety exhibited immunomodulatory activity, and that mycoloyl glycolipids with longer chain mycolic acids exhibited stronger activity in mice than did those with shorter chain mycolic acids. The mycoloyl glycolipids from Nocardia asteroides directly activated macrophages. Stimulation of above concentration with 0.16 microgram/ml of TDM or 0.8 microgram/ml of GM markedly enhanced production of PGE2 by mouse peritoneal macrophages. At higher concentrations above 100 micrograms/ml of TDM or 500 micrograms/ml of GM, IL-1 release was also enhanced.

Animals↗

PubMed1998

Application of acupuncture and moxibustion for keeping shape.

On the basis of TCM diferentiation, the authors have treated 359 adult female cases of non-obesity with undesirable body shape by combined application of body acupuncture and moxibustion and auricular acupuncture, and achieved quite good remoulding and orthopedic results, suggesting that acupuncture and moxibustion can very effectively regulate the somatotypic indexes of body weight, circumference of the chest, loin, hip and thigh, the ratio of the loin to hip, sebum thickness, obesity degree, body mass index and body fat percentage of the cases in the overweight group and orthopedic groups 1, 2. It is therefore concluded that acupuncture and moxibustion is a good therapy for obtaining a graceful body shape.

Acupuncture Therapy↗

PubMed1998

[Ultrasonic measurements of fetal thigh soft tissue thickness in the estimation of fetal weight].

OBJECTIVE: To study ultrasonic measurement of fetal thigh soft tissue thickness in the estimation of fetal weight. METHODS: Fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and fetal thigh soft tissue thickness (FTSTT) were measured by ultrasonography and analyzed with neonatal birth weight in 178 cases. RESULTS: There was significant correlation between FTSTT and neonatal birth weight (r = 0.8601), and it is better to estimate fetal weight with FTSTT than with the other parameters. The sensitivity and specificity for detection of macrosomia was 91% and 94%, respectively. The FTSTT was positively correlated with gestational age (r = 0.7070). CONCLUSION: The ultrasonic measurement of FTSTT is a simple, accurate and valuable index in estimation of fetal weight.

Adult↗

PubMed1998

[The expression of CD44, PCNA, vWF: Ag in non-Hodgkin's lymphoma and its relationship with the grade of malignancy].

OBJECTIVE: To study the expression of CD44, proliferating cell nuclear antigen (PCNA), vWF: Ag in normal lymphatic tissue and non-Hodgkin's lymphoma (NHL) and its implication. METHODS: Immunohistochemical assay was performed with a LSAB kit. RESULTS: 1. In normal lymphatic tissues, mature appearing small lymphocytes were positive for CD44, while proliferating immature lymphocytes in germinal center were negative. 2. High grade and intermediate grade NHL samples were strongly positive for CD44, the positive rate in the former was higher than in the latter (P < 0.05). In the ten low grade lymphoma samples, only two were weakly positive and, the rest were negative. The expression of PCNA showed the same manner as CD44. 3. The microvessels in NHL increased with the histological malignant grade. CONCLUSION: The expression of CD44 in normal lymphatic tissues is different from that in NHL. Combination of CD44 expression with PCNA expression and microvessel density seems a reliable parameter for judging malignant degree of NHL.

Humans↗

PubMed1998

[Relationship between plasma endothelin, nitric oxide, calcitonin gene-related peptide levels and pulmonary hemodynamics in patients with chronic cor pulmonale].

OBJECTIVE: To explore the relationship between plasma endothlin-1 (ET-1), nitric oxide (NO), calcitonin gene-related peptide (CGRP) levels and hypoxic pulmonary hypertension. METHOD: Cardiac catheterization was performed in 55 cases of chronic cor pulmonale to monitor the changes of their hemodynamic indices and to determine the levels of pulmonary arterial plasma ET-1, NO and CGRP. RESULT: The plasma ET-1 level of patients with pulmonary hypertension (Group A) was significantly higher than that of patients without pulmonary hypertension (Group B) and controls. The plasma NO level of group A was significantly lower than that of Group B and controls. The plasma CGRP level of ET-1 had a significantly negative correlation with PaO2 and positive correlation with pulmonary arterial pressure. The levels of NO and CGRP had significantly positive correlation with PaO2 and negative correlation with pulmonary arterial pressure. After 60-min oxygenation with 30% oxygen inhalation, the level of ET-1 decreased remarkably, but the levels of NO and CGRP went up notably. CONCLUSION: These results demonstrate that hypoxia affects plasma ET-1, NO, CGRP levels in patients with chronic cor pulmonale. ET-1, NO, CGRP play synergistic roles in regulation of pulmonary arterial pressure.

Adult↗

PubMed1998

[Preliminary studies on chemical constituents and pharmacological action of Eclipta prostrata L].

OBJECTIVE: To study the pharmacologically active components of Eclipta prostrata. METHOD: The components were extracted by alcohol and isolated by silica gel column and subjected to pharmacological screening. RESULT: Four compounds were isolated from E. prostrata, of which two were identified as stigmasterol and alpha-terthienyl. CONCLUSION: alpha-Terthienyl was isolated from the plant for the first time. The EtOAc part of alcoholic extraction exhibits significant hepatoprotective activity against carbon terachloride-induced liver injury in rats.

Alanine Transaminase↗

PubMed1998

[Cell clone technique for Taxus cuspidata Sieb. et Zuicc].

The cell clone technique was studied for Taxus cuspidata with needle-derived calli cells. The plating efficiency(PE) of the third generation of suspension culture cells was found to be the highest one and the PE of the medium solidified with phytagel was found to be almost the same as that of the medium solidified with low melting agarose gel. Solid-solid double layer culture was found to promote the PE of Taxus cuspidata cells moderately. A large number of stable cell lines with high growth rate were obtained and the browning problem of cells was completely solved via plate culture of the cell clones of T. cuspidata. The growth rate of the best cell line reached 0.4 g.FW/g.FW.d.

Cells, Cultured↗

PubMed1998

[The changes of electrogastrogram and gastrointestinal pressure following cholecystectomy].

OBJECTIVE: To investigate the mechanism and pathophysiological changes after abdominal surgery. METHOD: Twenty-two patients after cholecystectomy were selected to perform cutaneous electrogastrography (EGG) at least one hour before operation, and the first, the second and the third day after operation respectively. On the operative and postoperative days, gastroduodenojejunal manometry was performed in 17 of the 2 patients. RESULT: The percentage of EGG normal frequency on the operative day was obviously lower than that on the preoperative day (P < 0.001), and the percentage of bradygastria on the operative day was obviously higher than that on the preoperative day (P < 0.01). The postoperative EGG amplitude was obviously lower than the preoperative one (P < 0.001), and did not recover after three days. The phase III of the migrating motor complex (MMC) appeared within 24 hours after operation, and first appeared at the duodenum. MMC III was most vigorous at the duodenum in recording period, and was less at the antrum. The contractile power and the area of MMC III at antrum after operation were obviously lower than at duodenum and upper jejunum (P < 0.01). On the third day after operation, the contractile power was lower than normal (P < 0.01). CONCLUSION: Gastrointestinal motility dysfunction after cholecystectomy is related to EGG amplitude, and not to EGG frequency. The recovery of antrum MMC III is later than that of small bowl, resulting in delayed gastric emptying. The MMC III of small bowl resums in early period after abdominal surgery. Postoperative ileum is due the decrease of MMC III contractile power and the area after abdominal surgery, which represent the ability of gastrointestinal contraction.

Adult↗

PubMed1998

[Pharmacognostical study of Chinese drug ningxia beimu].

This paper deals with the macroscopic, microscopic and chemical characteristics of the bulbs of Fritillaria taipaiensis var. ningxiaensis. This crude drug could be distinguished by shape, size, hilum and striations of the sample grains.

Alkaloids↗