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Biomedical subjects

Sheng He

Publications and source records attributed to Sheng He.

At least 37 records · Page 2Linked to original sources
PubMed2006

[The autologous bone marrow mononuclear cell transplantation by intracoronary route treat patients with severe heart failure after myocardial infarction].

OBJECTIVE: To investigate the chronic effects of intracoronary autologous bone marrow mononuclear cell (BM-MNCs) transplantation in patients with refractory heart failure (RIHF) after myocardial infarction. METHODS: Thirty patients with RIHF (LVEF < 40%) were enrolled in this nonrandomized study, autologous BM-MNCs (5.0 +/- 0.7) x 10(7) were transplanted with via infarct-related coronary artery in 16 patients and 14 patients received standard medical therapy served as control. Baseline and follow up evaluations included complete clinical evaluations, plasma BNP, ANP, ET-1 measurements, echocardiography, PET, and Holter monitoring. RESULTS: Baseline characteristics were similar between the 2 groups. There were no major periprocedural complications. One patient developed ventricular premature contractions during cell infusion for several seconds and recovered spontaneously. Compared to pre-transplantation, plasma BNP and ET-1 significantly decreased and plasma ANP significantly increased at 7 days post transplantation; 6 minutes walking distance increased from (72.1 +/- 31.5) to (201.6 +/- 23.3) m (P < 0.01), LVEF increased 9.9% (P < 0.001) and FDG-PET revealed vital myocardium area increased (10.3 +/- 3.4)% (P < 0.01) at 3 months after BM-MNCs transplantation. At 6 months follow up, the NYHA class improved from (3.4 +/- 0.1 to 2.4 +/- 0.2, P < 0.001) and no patient died and 1 patient rehospitalized due to lower extremities edema. In control group, LVEF decreased 7.2% compared to baseline (P < 0.001) and was significantly lower than transplantation group at 3 months (P < 0.001). At 6 months follow up, the NYHA class increased from (3.5 +/- 0.1 to 3.9 +/- 0.1, P < 0.05), 2 patients died and 10 patients rehospitalized due to aggravated heart failure. CONCLUSION: Present study demonstrates that intracoronary transplantation of autologous BM-MNCs is safe and effective for treating patients with RIHF after myocardial infarction.

Bone Marrow Transplantation↗
PubMed2006

Feasibility and effectiveness of chemical bile duct embolization for chemical hepatectomy: a preliminary study.

BACKGROUND: The high operative risk of hepatectomy for specially located intrahepatic stones is still a problem to be solved. This study was undertaken to investigate the feasibility and effectiveness of chemical bile duct embolization for chemical hepatectomy. METHODS: Oxybenzene or absolute ethanol plus N-butyl-cyanoacrylate was employed for embolization. The feasibility, effectiveness and mechanism of chemical hepatectomy were preliminarily analyzed histologically or by Fas, TIMP-1, TGF-beta(1), and collagen I. RESULTS: Oxybenzene plus cyanonacrylate can preferably destroy and embolize the intrahepatic biliary duct, leading to the disappearance of hepatocytes in the periphery of embolized lobe and the achievement of effective chemical hepatectomy. The expressions of Fas, TIMP-1 and TGF-beta(1) in oxybenzene embolism group (88.90 +/- 38.10, 619.43 +/- 183.42, 185.22 +/- 70.39) and ethanol embolism group (72.39 +/- 29.51, 407.55 +/- 134.74, 163.56 +/- 51.75) were higher than those of biliary duct-ligated group (26.31 +/- 12.07, 195.31 +/- 107.67, 74.84 +/- 40.73) (P<0.05). The collagen I-positive percentage in the oxybenzene embolism group was also greater than that of the ethanol embolism group (33.97 +/- 12.51% vs. 20.67 +/- 8.09%, P<0.05). CONCLUSION: The effect of chemical hepatectomy may be achieved by chemical bile duct embolization.

Animals↗
PubMed2005

Cortical responses to invisible objects in the human dorsal and ventral pathways.

The primate visual system is believed to comprise two main pathways: a ventral pathway for conscious perception and a dorsal pathway that can process visual information and guide action without accompanying conscious knowledge. Evidence for this theory has come primarily from studies of neurological patients and animals. Using fMRI, we show here that even though observers are completely unaware of test object images owing to interocular suppression, their dorsal cortical areas demonstrate substantial activity for different types of visual objects, with stronger responses to images of tools than of human faces. This result also suggests that in binocular rivalry, substantial information in the suppressed eye can escape the interocular suppression and reach dorsal cortex.

Adult↗
PubMed2005

Orientation-tuned FMRI adaptation in human visual cortex.

Adaptation is a general property of almost all neural systems and has been a longstanding tool of psychophysics because of its power to isolate and temporarily reduce the contribution of specific neural populations. Recently, adaptation designs have been extensively applied in functional MRI (fMRI) studies to infer neural selectivity in specific cortical areas. However, there has been considerable variability in the duration of adaptation used in these experiments. In particular, although long-term adaptation has been solidly established in psychophysical and neurophysiological studies, it has been incorporated into few fMRI studies. Furthermore, there has been little validation of fMRI adaptation using stimulus dimensions with well-known adaptive properties (e.g., orientation) and in better understood regions of cortex (e.g., primary visual cortex, V1). We used an event-related fMRI experiment to study long-term orientation adaptation in the human visual cortex. After long-term adaptation to an oriented pattern, the fMRI response in V1, V2, V3/VP, V3A, and V4 to a test stimulus was proportional to the angular difference between the adapting and test stimuli. However, only V3A and V4 showed this response pattern with short-term adaptation. In a separate experiment, we measured behavioral contrast detection thresholds after adaptation and found that the fMRI signal in V1 closely matched the psychophysically derived contrast detection thresholds. Similar to the fMRI results, adaptation induced threshold changes strongly depended on the duration of adaptation. In addition to supporting the existence of adaptable orientation-tuned neurons in human visual cortex, our results show the importance of considering timing parameters in fMRI adaptation experiments.

Adaptation, Physiological↗
PubMed2005

Age-dependent brain activation during forward and backward digit recall revealed by fMRI.

In this study, brain activation associated with forward and backward digit recall was examined in healthy old and young adults using functional MRI. A number of areas were activated during the recall. In young adults, greater activation was found in the left prefrontal cortex (BA9) and the left occipital visual cortex during backward digit recall than forward digit recall. In contrast, the activation in the right inferior frontal gyrus (BA 44/45) was more extensive in forward digit recall than in backward digit recall. In older adults, backward recall generated stronger activation than forward recall in most areas, including the frontal, the parietal, the occipital, and the temporal cortices. In the backward recall condition, the right inferior frontal gyrus (BA44/45) showed more activation in the old group than in the young group. These results suggest that different neural mechanisms may be involved in forward and backward digit recall and brain functions associated with these two types of recall are differentially affected by aging.

Adult↗
PubMed2005

Viewer-centered object representation in the human visual system revealed by viewpoint aftereffects.

Are there neurons representing specific views of objects in the human visual system? A visual selective adaptation method was used to address this question. After visual adaptation to an object viewed either 15 or 30 degrees from one side, when the same object was subsequently presented near the frontal view, the perceived viewing directions were biased in a direction opposite to that of the adapted viewpoint. This aftereffect can be obtained with spatially nonoverlapping adapting and test stimuli, and it depends on the global representation of the adapting stimuli. Viewpoint aftereffects were found within, but not across, categories of objects tested (faces, cars, wire-like objects). The magnitude of this aftereffect depends on the angular difference between the adapting and test viewing angles and grows with increasing duration of adaptation. These results support the existence of object-selective neurons tuned to specific viewing angles in the human visual system.

Adaptation, Physiological↗
PubMed2005

[Experimental study of targeting therapy of breast cancer with 131I-labeled epidermal growth factor].

OBJECTIVE: To investigate the effectiveness of (131)I-epidermal growth factor (EGF) on the proliferation of a heterologous graft in nude mice bearing human breast infiltrating duct carcinoma. METHODS: EGF/HAS was labeled with (131)I by chloramines-T method. Human breast cancer xenografts with positive EGFR expression were established in nude mice. The nude mice were injected with normal saline, Epirubicin Hydrochloride, (131)I-EGF, (131)I-HAS, (131)I intravenously and (131)I-EGF intratumoral administration respectively. The tumor growth inhibition rate was determined by measurement of tumor volume. Different examinations were carried out. RESULTS: There was remarkable significant difference of tumor volumes at 26th day among (131)I-EGF trial groups, (131)I, (131)I-HAS, and the negative control group. The tumor growth inhibition rate of (131)I-EGF trial groups was 82.0%, 80.7% respectively. Compared with the negative control group, the (131)I-EGF trial groups remarkably suppressed the growth of tumor (P < 0.05). Irreversible destruction of tissues in (131)I-EGF groups was observed under light and electron microscope. There was no evidence of hepatotoxicity, renal toxicity and myelotoxicity in nude mice bearing human breast cancer given (131)I-EGF over a 4-wk observation period. CONCLUSION: (131)I-EGF has obvious antitumor effects on a heterologous graft in nude mice bearing human breast infiltrating duct carcinoma, with little obvious side effects.

Animals↗
PubMed2005

A preliminary study of applying chemical biliary duct embolization to chemical hepatectomy in rats.

The high recurrence of hepatolithiasis, together with the high operative risk of hepatectomy for specially located stones, has not been settled effectively to date. Thus, this study was designed to investigate the feasibility of applying chemical biliary duct embolization (CBDE) to chemical hepatectomy in rats. As revealed in our results, the intrahepatic biliary ducts could be partially or completely occluded by both phenol and absolute ethanol. In addition, the embolization effect was greatly enhanced by further using cyanoacrylate. Also noteworthy is that CBDE resulted in massive death of hepatocytes, which were replaced by proliferated bile ductules and collagen. More importantly, the hepatocytes disappeared completely in the periphery of the embolized lobe where chemical hepatectomy was achieved. As for the comparison of embolic agents, the combination of phenol and cyanoacrylate exhibited even better fibrogenic effects than the combination of ethanol and cyanoacrylate. In conclusion, CBDE might be a promising approach for achieving the effects of chemical hepatectomy. The combination of phenol and cyanoacrylate potentially acted as a more effective agent for biliary duct embolization.

Animals↗
PubMed2005

The practical value of applying chemical biliary duct embolization to chemical hepatectomy for treatment of hepatolithiasis.

BACKGROUND: The high recurrence rate of hepatolithiasis, together with the high operative risk of hepatectomy for specifically located stones, has not been effectively settled until now. Thus, the aim of this study was to investigate the feasibility and effectiveness of using chemical biliary duct embolization (CBDE) to achieve chemical hepatectomy in a rabbit model of hepatolithiasis. MATERIALS AND METHODS: The animal model of hepatolithiasis was established using the methods of obstruction plus infection. Seven days later, the left hepatic ducts were embolized using phenol plus cyanoacrylate or absolute ethanol plus cyanoacrylate. Subsequently, the influence of CBDE on bile duct, liver, and stone formation was analyzed by histology, RT-PCR for procollagen, biochemistry, and enzymatic histochemistry for beta-glucuronidase (beta-G). RESULTS: CBDE resulted in the entire ablation of the diseased biliary duct mucosa and the complete occlusion of the diseased biliary duct lumen, thus effectively eradicating chronic proliferative cholangitis and preventing stone formation. More importantly, CBDE also resulted in the complete fibrosis and "self-cut" in the periphery of the embolized lobe, thus achieving chemical hepatectomy. Also of note, the embolized lobe exhibited a much lower level of endogenous beta-G than the nonembolized lobe, indicating an inhibitory effect of CBDE on beta-G. Besides, the mRNA level of procollagen I in the embolized bile duct wall of phenol embolization group was significantly higher than the ethanol embolization group. CONCLUSION: Chemical biliary duct embolization, especially using phenol plus cyanoacrylate, may prevent the recurrence of intrahepatic stone and concurrently achieve the effect of chemical hepatectomy.

Animals↗
PubMed2005

[Radiobiological effect of 131I radiolabeled recombinant human epidermal growth factor on nude mice with human breast cancer].

The radiobiological effect of 131I radiolabeled recombinant human epidermal growth factor (131I-rhEGF) on nude mice with human breast cancer was assessed in this study. The tissue mainly uptaking 131I-rhEGF was found by tissue distribution assay in mice. The radiation breakdown of the tissue greatly collecting 131I-rhEGF was examined by biochemical test and biopsy in nude mice with human breast cancer. The tissue distribution assay of 131I-rhEGF in mice showed that 131I-rhEGF greatly accumulated in kidney, liver, spleen and blood. The biochemical test and biopsy revealed that 131I -rhEGF injected twice (dosing once is analogous to 14.58 GBq in a person with 50 kg, once every 14 days) had an effective killing effect on tumor but had no effect of radiation breakdown on kidney, liver,spleen and blood-cell forming tissue in mice with human breast cancer. Therefore, 131I-rhEGF is a drug unharmful to normal tissues in the course of the receptor-mediated target radiotherapy for breast cancer.

Animals↗
PubMed2005

[Tropism of adult liver stem cells toward hepatocellular carcinoma cells in vitro].

OBJECTIVE: To explore the biological behavior of adult liver stem cells in a co-cultured system of them with hepatocellular carcinoma (HCC) cells without direct contact between the two kinds of cells. METHODS: WB-F344, a kind of rat adult liver stem cell, and rat embryonic fibroblasts (REF) from a primary culture were engineered to express enhanced green fluorescent protein (EGFP) by recombinant adenoviral-mediated methods. Two kinds of cells marked with EGFP were established, namely WB-EGFP and REF-EGFP. After the HCC cells grew to 40%-60% confluence in the culture dish with a 10-mm cell-free area, a similar number of WB-EGFP and REF-EGFP were placed in the blank areas respectively. Then, we constantly studied the movement behavior of WB-EGFP in the co-culture system with HCC cells. RESULTS: The results showed that WB-EGFP cells migrated to the area of HCC cells slowly. Their appearance was found not only when WB-EGFP cells were seeded into the cell-free area at the center of the dish, but also when seeded into the blank area at the extreme edge of the plate. This trait was not observed in the co-cultured system of REF-EGFP and HCC cells, and most REF-EGFP were still localized in their initial area after 72 hours of incubation. CONCLUSIONS: The results mean that adult liver stem cells have a biological behavior of selective tropism toward HCC cells in vitro, and suggest a possibility of using migratory liver stem cells as a delivery vehicle for gene therapy for HCC.

Adenoviridae↗
PubMed2004

Competing global representations fail to initiate binocular rivalry.

A longstanding debate in binocular rivalry literature is whether the perceptual competition in rivalry occurs at an early or late stage of visual processing. Central to this debate is the determination of the source of the competition. Overwhelming evidence exists that local interocular differences can lead to binocular rivalry, but it is not yet clear whether interocular conflicts at the global level are sufficient to generate binocular rivalry. The current study adopted a novel stimulus that enabled the introduction of dramatic global differences between the two eyes with compatible local elements. Results show that global differences between the two eyes' images do not result in rivalry if local elements are compatible. The implication of these findings is that the registration of competing interocular information, necessary to generate binocular rivalry, is performed at an early stage of visual processing prior to global analysis of the image.

Dominance, Ocular↗
PubMed2004

Strong influence of test patterns on the perception of motion aftereffect and position.

In a completely linear system, the behavior of a square wave pattern can be predicted by its sinusoidal components. However, we observed a complete breakdown of the linear system prediction in the perception of the motion aftereffect (MAE). The duration of the MAE was measured following a one-minute adaptation to a rotating radial grating. Three different luminance patterns were used for both the adaptation and test stimulus: (1) sine wave, (2) square wave, and (3) complex grating with the same Fourier amplitude spectrum as the square wave, but with randomized phases. The sine wave stimulus generated the highest magnitude MAE, followed by the random-phase complex grating, and lastly the square wave grating. To test whether the square wave grating is a weak adaptor or a weak test for the MAE, we performed a cross adaptation experiment in which the sine wave, square wave, and complex gratings were paired in seven ways. Results show that the strength of the MAE critically depended on the test pattern. Regardless of the adaptor, MAE strength is in a decreasing order with the test pattern as sine wave grating, complex grating, and square wave grating. Further experiments ruled out the possibility that differential MAEs between these conditions are due to different peak contrasts in these patterns. Additionally, the MAE from a square wave grating as the test pattern is not accompanied by a significant concurrent shift in the apparent position. Linear system theory cannot predict the magnitude of the MAE using complex gratings. The spatial features of a test stimulus, such as position reliability or luminance uniformity, strongly influence the magnitude of MAE. Sharp edges and local luminance uniformity can greatly reduce MAE.

Adaptation, Ocular↗
PubMed2004

Local factors determine the stabilization of monocular ambiguous and binocular rivalry stimuli.

Perceptual alternation in viewing bistable stimuli can be slowed or halted if the stimuli are presented intermittently. Memory of the recent perceptual experience has been proposed to explain this stabilization effect. But the nature of this "perceptual memory" remains unclear. By using a bistable rotating cylinder and two dichoptically presented orthogonal gratings, we explored the features that are important for the stabilization by changing a particular feature of the stimuli between alternate presentations. For the rotating cylinder, changing its color, rotating speed, size, or its stereo depth had no or minimal effect on the stabilization of its perceived rotation direction. For binocular rivalry, when the two gratings were matched in strength and then swapped between the two eyes synchronously with the intermittent presentation, the percepts were usually stabilized to one eye. In both cases, perceptual stabilization occurred only if the stimuli were presented to the same retinal location. These results suggest that the stabilization of monocular bistable stimuli is likely due to the removal of local adaptation, insensitive to the features that define the object identity. For binocular rivalry, preservation of the direction of interocular suppression rather than memory of the stimulus identity accounts for the stabilization effect.

Adult↗
PubMed2004

Stabilized structure from motion without disparity induces disparity adaptation.

3D structures can be perceived based on the patterns of 2D motion signals. With orthographic projection of a 3D stimulus onto a 2D plane, the kinetic information can give a vivid impression of depth, but the depth order is intrinsically ambiguous, resulting in bistable or even multistable interpretations. For example, an orthographic projection of dots on the surface of a rotating cylinder is perceived as a rotating cylinder with ambiguous direction of rotation. We show that the bistable rotation can be stabilized by adding information, not to the dots themselves, but to their spatial context. More interestingly, the stabilized bistable motion can generate consistent rotation aftereffects. The rotation aftereffect can only be observed when the adapting and test stimuli are presented at the same stereo depth and the same retinal location, and it is not due to attentional tracking. The observed rotation aftereffect is likely due to direction-contingent disparity adaptation, implying that stimuli with kinetic depth may have activated neurons sensitive to different disparities, even though the stimuli have zero relative disparity. Stereo depth and kinetic depth may be supported by a common neural mechanism at an early stage in the visual system.

Adaptation, Ocular↗
PubMed2004

Cross-modal temporal order memory for auditory digits and visual locations: an fMRI study.

A function of working memory is to remember the temporal sequence of events, often occurring across different sensory modalities. To study the neural correlates of this function, we conducted an event-related functional magnetic resonance imaging (fMRI) experiment with a cross-modal memory task. Subjects were required to recall auditory digits and visual locations either in mixed order (cross-modality) or in separate order (within-modality). To identify the brain regions involved in the memory of cross-modal temporal order, we compared the blood oxygenation level-dependent (BOLD) response between the mixed and the separate order tasks. As a control, cortical areas sensitive to the memory load were mapped by comparing the 10-item condition with the 6-item condition in the separate order task. Results show that the bilateral prefrontal, right premotor, temporo-parietal junction (TPJ) and left superior parietal cortices had significantly more activation in the mixed task than in the separate task. Some of these areas were also sensitive to the memory load, whereas the right prefrontal cortex and TPJ were relatively more sensitive to the cross-modal order but not the memory load. Our study provides potential neural correlates for the episodic buffer, a key component of working memory as proposed previously [Baddeley. Trends Cogn Sci 2000;4:417-423].

Acoustic Stimulation↗