Seasonal variation and spatial distribution of polycyclic aromatic hydrocarbons in atmospheric PM10 of Beijing, People's Republic of China.
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Air Pollutants↗
Biomedical subjects
T Mao
Publications and source records attributed to T Mao.
A comparison of ultrasound treatment on primary and secondary sludges.
Ultrasound treatment of primary and secondary sludges was conducted to improve the qualities of sludges for the anaerobic digestion. The impacts of different sonication times, sonication densities and solids concentrations on ultrasonication efficiency were examined. The experimental results indicated that the significant reduction in particle size and increase in soluble organics could be achieved, implying that ultrasonication could offer a feasible treatment method to efficiently disintegrate sludge. The greater decrease in particle size and increase in soluble organics of sludge indicated that the secondary sludge has a more remarkable improvement after sonication over the primary sludge. With respects to the extent of disintegration and energy consumption, higher sonication density performed more effectively in terms of specific energy. There exists an optimal solids concentration range for both the sludges for optimum sonication. Within the optimal solids concentration range, efficient sonication can be effected and sludge would be disintegrated efficiently. The ultrasound would be attenuated by scattering and absorption if the solids concentration exceeds the optimal range. It appeared from the study that the mechanical shear forces caused by ultrasonic cavitation could be a key factor for sludge disintegration and collapse of cavitation bubbles could significantly alter the sludge characteristics.
Particle Size↗
Injectable bone.
Temperature-dependent polymerising polyethylene oxide hydrogel was used as a vehicle to deliver bone marrow mesenchymal cells by injection in six nude mice, four mice acting as controls, to study generation of new bone in the cell-hydrogel complex. Mesenchymal cells were harvested by in vitro cell culture, and cells were seeded into polyethylene oxide solution. The density of the suspension was adjusted to 5 x 10(7)ml(-1). The hydrogel was obtained by adjusting the temperature to over 6 degrees C. Aliquots of 0.5 ml of the cell-hydrogel complexes were injected subcutaneously into the backs of the six experimental mice, and 0.5 ml of hydrogel alone was injected into the four controls. Generation of new bone was studied by gross inspection, radiographs, and histological examination. Two months after injection hard nodes had formed subcutaneously in all six mice, whereas in the control group the hydrogel had been absorbed completely and only soft tissue was present at the site of injection. A shadow could be seen on the radiographs of all cell-seeded mice. On histological examination of the nodes there was trabecular bone and some areas of neocartilage. This method of generating new bone might be of potential clinical use.
Animals↗
Vascular osteomuscular autograft prefabrication using coral, type I collagen and recombinant human bone morphogenetic protein-2.
In 20 male Sprague-Dawley rats, 10 pieces of L-shaped coral combined with type I collagen and recombinant human bone morphogenetic protein-2 (rhBMP-2) and 10 discs (diameter 5 mm) were wrapped in the gracilis muscle, and left pedicled on the femoral vessels. Untreated coral was buried in muscle at a distant control site in 4 animals. After 3 weeks, autografts were examined for the shape of new bone, vascular patency, and induction of bone. In all grafts in viable tissue, heterotopic bone was formed. The shape of the new bone was the same as that of the coral, and there was no significant inflammatory reaction. Part of the coral in the composite was absorbed. Bone was not formed in any of the control sites. Coral and type 1 collagen are effective as a carrier for BMP to prefabricate vascular osteomuscular autografts with designed shape. There is a potential clinical application for BMP to bioengineer microvascular free flaps with intrinsic skeletal muscle for maxillofacial reconstruction.
Animals↗
Cocoa procyanidins and human cytokine transcription and secretion.
We examined whether cocoa, in its isolated procyanidin fractions (monomer through decamer), would modulate cytokine production at the levels of transcription and protein secretion in both resting and phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC). In resting cells, interleukin (IL)-1beta and IL-4 gene expression from cocoa-treated cells varied markedly among the subjects tested. However, at the protein level, the larger fractions (pentamer through decamer) stimulated a dramatic increase in IL-1beta concentration (up to ninefold) with increasing degree of polymerization. Similarly, these larger fractions augmented IL-4 concentration by as much as 2 pg/ml, whereas the control displayed levels nearly undetectable. In the presence of PHA, gene expression also seemed to be most affected by the larger procyanidin fractions. The pentameric through decameric fractions increased IL-1 beta expression by 7-19% compared with PHA control, whereas the hexameric through decameric fractions significantly inhibited PHA-induced IL-4 transcription in the range of 71-86%. This observation at the transcription level for IL-1 beta was reflected at the protein level in PHA-stimulated PBMC. Significant reductions in mitogen-induced IL-4 production were also seen at the protein level with the hexamer, heptamer and octamer. Individual oligomeric cocoa fractions were unstimulatory for IL-2 in resting PBMC. However, when induced with PHA, the pentamer, hexamer and heptamer fractions caused a 61-73% inhibition in IL-2 gene expression. This study offers additional data for the consideration of the health benefits of dietary polyphenols from a wide variety of foods, including those benefits associated specifically with cocoa and chocolate consumption.
Biflavonoids↗
[The construction and physical-mechanical characterization of polymer foams of D. L-PLA].
This study was intended to construct biogradable polymer foam used in tissue engineering. The D. L-PLA was supplied by chengdu institute of organic chemistry. Biogradable polymer membranes were prepared with a novel solvent-casting particulate-leaching technique, then, the constituent membranes with the proper order were laminated to produce three-dimensional foams with continuous pore structure and morphology. Afterwards, the physical-mechanical property of polymer foams were tested. The test results indicated that the lamination process did not change the physical-mechanical property of the polymer membranes.
Biocompatible Materials↗
The therapeutic effect of Ginkgo biloba extract in SHR rats and its possible mechanisms based on cerebral microvascular flow and vasomotion.
This paper aimed to investigate the therapeutic effect of an extract of Ginkgo biloba leaves (EGb 761) on hypertension and its possible mechanisms in the view of cerebral microcirculation. Twenty normotensive rats and 24 SHR rats were used. Surgical preparation was made to produce a cranial window for observation of the capillary network on the cerebral cortex. The intravital videomicroscopy equipped with digital image processing system and laser Doppler flowmeter were used for this study. The arterial blood pressure, red cell velocity (V), microvacular diameter (D), number of open capillaries (OCN), circulating endothelial cells (CEC) in blood, relative blood flow (Flow) and frequency (Fc), amplitude (AMP) of vasomotion were measured. The obtained data were compared between EGb-treated rats that received per os 100 mg/kg/d for 9 days and placebo control rats. Untreated SHR rats showed very severe dysfunction in the microcirculation with high blood pressure (213 +/- 16.7 mmHg). The blood pressure decreased significantly to 153 +/- 20 mmHg in EGb-treated SHRs group, compared with those of untreated rats (p < 0.01). Both normotensive and hypertensive rats increased the blood flow velocity and LDF flow after EGb-treatment. The vasomotion property, the CEC and OCN changed greatly in EGb-treated SHR rats, but no significant difference was observed in normotensive rats. It was suggested that EGb 761 had therapeutic effect on SHR rats by increasing blood perfusion, regulating vasomotion function, opening efficiently capillaries and releasing the peripheral resistance. The injured vascular endothelium of SHR rats was also partly reversed by EGb-treatment. It was concluded that EGb 761 could be used to regulate hypertension and to protect the cerebral microcirculatory function.
Animals↗
[Experimental study on prefabricating iliac grafts using composite bone].
OBJECTIVE: To investigate the feasibility of prefabricating a specified shape autograft capable of transfer using coral and type I collagen as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS: In this study, the composite of rhBMP-2, coral and type I collagen was made certain shape to prefabricate vascularized osteomuscular autograft capable of microvascular free tissue transfer and autogenous bone graft with certain shape and titanium implant in it. The composite was implanted in the iliac area in dog with the titanium implant at the same time. After 3 months and 4 and a half months of implantation, the composites were studied with gross measurement, X-ray, and histological examinations. RESULTS: After 3 months, composited bone was turned to bone tissue, and the shape of iliac bone was changed with implant in it, bone interface was seen between new bone and implant. And new bone was matured after 4 and a half months. CONCLUSION: Coral and type I collagen are effective carrier for rhBMP-2 to prefabricate vascular osteomuscular autograft with certain shape. The use of rhBMP-2 for tissue engineered microvascular free bone flaps has an unlimited potential and adds a new dimension to maxillofacial reconstruction.
Animals↗
[The experimental study on the activity of rhBMP-2, coral and collagen composites inducing intramuscle bone].
OBJECTIVE: To investigate the ectopic bone induction activity of the composite of coral, collagen and rhBMP-2, and the degradation of the carriers of rhBMP-2. METHODS: The composites of rhBMP-2, coral and collagen were implanted into the muscle pouches of mice. The mice were divided into the following four groups. Group H: each composite had 2 mg rhBMP-2, Group L: each composite had 0.5 mg rhBMP-2, Group J: each composite had only type I collagen, Group C: only coral was implanted in the muscle of mouse. Each group had 20 mice. Every 5 mice in each group were killed postoperatively after 1, 2, 4 and 8 weeks. The ectopic osteoinductive activity was assessed with histology and histomorphometry. The point counting method was applied to measure the formation of new bone and cartilage and the degradation of coral in the composites. The data was analyzed statistically using t test. RESULTS: There was no obvious morbidity in any of the animals in this study, and no wound infection, bleeding, or feeding difficulties postoperatively. The samples were examined histologically. Cartilage and bone induction occurred in Group H and L. After 1 Week, new bone was observed in Group H, and cartilage formation occurred mainly in Group L. After 2 weeks, both cancellous bone and bone marrow elements were present in Group H and L. New bone formation was not uniform throughout the specimen. Part of the coral in the composites was not absorbed between 2 to 4 weeks postoperatively. At the 8th week, the coral in the composite was absorbed completely. While in Group J and C there was not any new cartilage or bone formation. According to the statistical analysis, bone formation occurred 2 weeks earlier in Group H than in Group L after operation. From 4 postoperative weeks, no difference of the bone formation rate was observed between Group H and Group L. The degradation rate of coral in Group C was the fastest among the four groups. CONCLUSION: The composites of rhBMP-2, coral and collagen are degradable bone substitutes with bone induction and conduction, and induce dosedependent and time-dependent amounts of intramuscle bone in mice during limited postoperative period. The coral in the composites could be absorbed completely.
Animals↗
[Cartilage matrix synthetic ability of rabbit articular chondrocytes cultured in vitro].
OBJECTIVE: To observe the ability of matrix synthesis of rabbit articular chondrocytes cultured in vitro. METHODS: Rabbit articular chondrocytes were acquired by digestion of 0.1% type II collagenase and cultured in vitro, then cell morphology and ultrastructure were observed with phase-contrast microscope and scanning electronic microscope. With continuous culturing of chondrocytes in DMEM medium containing 15% FBS, synthesis of cartilage matrix was observed by using microscope and safranine-O staining. RESULTS: The cultured chondrocytes were polygonal cells. There were many rough endoplasmic reticula and mitochondria in cytoplasm, and a lot of secretory vesicles under cell membrane and in the cytoplasm. When cultured for 10 days, some small and white nodules were formed on the bottom of the culture dishes, and volcanic-mouth-like structures were formed when cultured for 20 days. Both these nodules and structures contained GAG-positive substances were demonstrated by safranine-O staining. CONCLUSION: Chondrocytes can produce matrix and cartilage-like tissue in vitro, so it is feasible to produce cartilage by culturing chondrocytes in vitro.
Animals↗
Coral as a carrier for recombinant human bone morphogenetic protein-2.
By combining coral with recombinant human bone morphogenetic protein-2 (rhBMP-2), rhBMP-2/coral composite was obtained in this study. Following implantation of the composite into the muscle pouches of mice, cartilage growth was induced in the pores or on the surface of the implants at one week, woven bone at three week and lamellar bone with bone marrow at six week, and coral was absorbed partially. The induced formation of endochondral bone was time-related and rhBMP-2 dose-related. The results of this study indicate that the composite possesses a superior ability of osteogenesis, and coral acts as one of the most suitable rhBMP-2 slowrelease carriers currently available. The composite will be a new type of bone substitute to be used in orthopaedics and maxillofacial surgery.
Animals↗
Prolonged asymptomatic dense deposit disease in Chinese. Report of 2 cases in Taiwan.
Dense deposit disease (DDD) is a less common form of membranoproliferative glomerulonephritis (MPGN). The disease occurs predominantly in children and young adults and the prognosis is variable. DDD varies considerably in incidence among different populations and has not been reported in Chinese. Herein we reported 2 cases of DDD in young Chinese girls in Taiwan. Although 1 case (case 2) had mild hypertension, both patients had asymptomatic proteinuria and ran a benign course of 8 and 14 years, respectively. The histological features of case 1 resembled membranous glomerulonephritis (MGN) on hematoxylin-eosin stain, but revealed DDD on periodic acid Schiff and chromotrope-2R silver methenamine stains. Whereas case 2 showed focal MPGN on light microscopy, she had a fine granular immunofluorescence pattern resembling MGN. Characteristic intramembranous dense deposits were demonstrated by electron microscopy in the basement membranes of the glomeruli, Bowman's capsules and the renal tubules. Both patients were followed closely, and had stable normal renal function 1 year after renal biopsy.
Adult↗
An experimental study on rhBMP-2 composite bone substitute for repairing craniomaxillary bone defects.
OBJECTIVE: To measure bone regenerative effects in animal calvarial or mandibular critical-size defects using recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with four selected carriers. MATERIALS AND METHODS: The composite bone grafts were obtained by combining rhBMP-2 with chitin, coral, coral-based porous HA (CHA), and xenogeneic cancellous bone, respectively. These materials were implanted on the calvarial or mandibular defect of rabbits and on the calvarial defect of rats. Each carrier material was also studied as a control group. The animals were examined 2, 4, 8, and 12 weeks after implantation by radiography, histology (under light microscope and scanning electron microscope), immunohistochemistry, and biomechanics. RESULTS: The results showed that the composite graft was absorbed gradually after it was implanted into the defect, during which time new bone was formed within the combined material in the defect site; the amount of new bone increased as time elapsed. At 12 weeks the composite was replaced completely by bone except in the CHA group. In contrast, a large amount of fibrous tissue, and little new bone, formed on the area of the bone defect when the carrier material alone was implanted. CONCLUSIONS: All materials tested seem to be suitable carriers for rhBMP-2, which plays a very important role in new bone formation. These composite bone substitutes may be ideal materials for repairing various bone defects in the craniomaxillofacial region.
Animals↗
[An experimental study on the bone repairing ability of recombinant human bone morphogenetic protein-2-coral composited artificial bone].
OBJECTIVE: To improve the bone repairing ability of coral. METHODS: Recombinant human bone morphogenetic protein-2 (rhBMP-2)-coral composited artificial bone was used. The composite was implanted into rabbit calvarial critical-size defects, and coral alone was implanted as control. The rabbits were sacrificed at 2, 6, 12 weeks respectively after operation. The bone repairing ability was assessed by histology and image analysis system. RESULTS: The composite repairing the bone defect both in osteoconductive and osteoinductive manners was seen, repairing ability and effect were better than those of coral. CONCLUSION: The composite is ideal as a bone graft substitute.
Animals↗
[Relationship between insulin resistance and coronary heart disease in non-insulin-dependent diabetes mellitus patients].
Recent clinical studies showed that an independent association between hyper-insulinaemia and coronary heart disease (CHD) in men with normal glucose tolerance. In non-insulin-dependent diabetes mellitus (NIDDM) it is less clear. Therefore, we evaluated insulin-sensitivity index, plasma glucose, insulin, lipoproteins and apolipoproteins in 40 male NIDDM patients with CHD, and compared them with 36 male NIDDM patients without CHD. The insulin-sensitivity index determined by the reverse of fasting plasma glucose and insulin product. The results showed that the subjects with CHD had significantly lower insulin-sensitivity index (P < 0.01) compared to those without CHD. Using step-wise logistic regression analgsis, we found insulin-sensitivity indexes (OR 0.237, 95%CI 0.0909-0.6167, P = 0.0032) were negatively associated with CHD, and were independent from other cardiovascular risk factors such as age, body mass index, hypertension, and hyperlipemia. We conclude that in NIDDM patients with CHD are more insulin resistant compared to those without CHD. Insulin resistance is associated with CHD, and independent from other cardiovascular risk factors.
Coronary Disease↗
[An experimental study on the effect of xenogeneic bone combined with human recombinant bone morphogenetic protein-2].
OBJECTIVE: To determine the ability of a new type of composited xenogeneic bone to repair the bone defect. METHODS: The new type of composited xenogeneic bone was obtained by combining the treated cancellous bone with recombinant human bone morphogenetic protein-2 (rhBMP-2) and was implanted in the bone defect of rabbit. RESULTS: There were a large amount of new bone formation within the combined material and the amount was increasing as the time lapsed in the area of the bone defect. In contrast, there were a lot of fibrous tissues with a little new bone formed when the treated cancellous bone was implanted alone. CONCLUSION: The results imply that the rhBMP-2 plays a very important role in new bone formation and the composited xenogeneic bone appears to be an ideal material for the repair of bone defect.
Animals↗
[A biomechanical study on the bone repairing ability of recombinant human bone morphogenetic protein-2-coral composited artificial bone].
To improve bone repairing ability of coral, recombinant human bone morphogenetic protein-2 (rhBMP-2)-coral composited artificial bone was obtained by combining coral with rhBMP-2 in this experiment. The composite was implanted into rabbit calvarial critical-size defects and coral alone was implanted as control. The bone repairing ability was assessed by radiography, histology and biomechanics. The results showed that implants were absorbed gradually after they was implanted into the defects. In the meantime, the new bone was formed and the mechanical strength was reinforced uninterruptedly in bone defect regions. At 12 weeks, the implants were replaced completely by bone, and the mechanical strength was entirely restored. These suggest that the composite possess a superior bone repairing ability and may be one of the most perfect bone graft substitutes currently available.
Animals↗
Isolation and identification of berberine from cell cultures of Coptis chinensis.
Calli were formed by the young leaves of Coptis chinensis inoculated onto a 6,7-V solid medium containing 1.0-2.0 mg/L of 2,4-D and 0.1 mg/L of kinetin. The loose calli were chosen and transferred into a liquid medium and free cells and cell aggregates were obtained. Cell lines with a higher content of berberine were selected by irradiation of suspension culture and a plate-screening technique. After 35 subcultures, the selected cell lines were cultured in a larger quantity for the extraction of alkaloids. Yellow crystals were obtained from the extracts and identified as berberine by TCL, UV and IR absorption, and mass spectrography. They have the same molecular structure and anti-bacterium activities as the berberine obtained from natural plants.
Berberine↗