Organization of cortical and thalamic input to pyramidal neurons in mouse motor cortex

Determining how long-range synaptic inputs engage pyramidal neurons in primary motor cortex (M1) is important for understanding circuit mechanisms involved in regulating movement. We used channelrhodopsin-2-assisted circuit mapping to characterize the long-range excitatory synaptic connections made by multiple cortical and thalamic areas onto pyramidal neurons in mouse vibrissal motor cortex (vM1). Each projection innervated vM1 pyramidal neurons with a unique laminar profile. Collectively, the profiles for different sources of input partially overlapped and spanned all cortical layers. Specifically, orbital cortex (OC) inputs primarily targeted neurons in L6. Secondary motor cortex (M2) inputs excited neurons mainly in L5B, including pyramidal tract neurons. In contrast, thalamocortical inputs from anterior motor-related thalamic regions, including VA/VL (ventral anterior thalamic nucleus/ventrolateral thalamic nucleus), targeted neurons in L2/3 through L5B, but avoided L6. Inputs from posterior sensory-related thalamic areas, including POm (posterior thalamic nuclear group), targeted neurons only in the upper layers (L2/3 and L5A), similar to inputs from somatosensory (barrel) cortex. Our results show that long-range excitatory inputs target vM1 pyramidal neurons in a layer-specific manner. Inputs from sensory-related cortical and thalamic areas preferentially target the upper-layer pyramidal neurons in vM1. In contrast, inputs from OC and M2, areas associated with volitional and cognitive aspects of movements, bypass local circuitry and have direct monosynaptic access to neurons projecting to brainstem and thalamus.

Long-range neuronal circuits underlying the interaction between sensory and motor cortex

In the rodent vibrissal system, active sensation and sensorimotor integration are mediated in part by connections between barrel cortex and vibrissal motor cortex. Little is known about how these structures interact at the level of neurons. We used Channelrhodopsin-2 (ChR2) expression, combined with anterograde and retrograde labeling, to map connections between barrel cortex and pyramidal neurons in mouse motor cortex. Barrel cortex axons preferentially targeted upper layer (L2/3, L5A) neurons in motor cortex; input to neurons projecting back to barrel cortex was particularly strong. Barrel cortex input to deeper layers (L5B, L6) of motor cortex, including neurons projecting to the brainstem, was weak, despite pronounced geometric overlap of dendrites with axons from barrel cortex. Neurons in different layers received barrel cortex input within stereotyped dendritic domains. The cortico-cortical neurons in superficial layers of motor cortex thus couple motor and sensory signals and might mediate sensorimotor integration and motor learning.

Inputs to the dorsal striatum of the mouse reflect the parallel circuit architecture of the forebrain

The basal ganglia play a critical role in the regulation of voluntary action in vertebrates. Our understanding of the function of the basal ganglia relies heavily upon anatomical information, but continued progress will require an understanding of the specific functional roles played by diverse cell types and their connectivity. An increasing number of mouse lines allow extensive identification, characterization, and manipulation of specified cell types in the basal ganglia. Despite the promise of genetically modified mice for elucidating the functional roles of diverse cell types, there is relatively little anatomical data obtained directly in the mouse. Here we have characterized the retrograde labeling obtained from a series of tracer injections throughout the dorsal striatum of adult mice. We found systematic variations in input along both the medial–lateral and anterior–posterior neuraxes in close agreement with canonical features of basal ganglia anatomy in the rat. In addition to the canonical features we have provided experimental support for the importance of non-canonical inputs to the striatum from the raphe nuclei and the amygdala. To look for organization at a finer scale we have analyzed the correlation structure of labeling intensity across our entire dataset. Using this analysis we found substantial local heterogeneity within the large-scale order. From this analysis we conclude that individual striatal sites receive varied combinations of cortical and thalamic input from multiple functional areas, consistent with some earlier studies in the rat that have suggested the presence of a combinatorial map.

Effect of sonication on UV disinfectability of primary effluents

In this paper, the effect of sonication on the UV disinfection kinetics of primary effluents was investigated. Wastewater samples were collected from local municipal treatment plants and were sonicated with a 20-kHz ultrasound reactor at constant power but varying sonication times. Sonicated samples were irradiated using low-pressure UV light to obtain the UV dose-response curves (DRC). Results showed that sonication improved the UV disinfection of primary effluents by (1) increasing the initial slope of DRC (i.e., k1) and (2) decreasing the tailing level of the UV dose-response curve (i.e., beta). This improvement was confirmed to be caused by the breakage of large particles (> 60 microm) that are known to protect coliforms from UV photons. It also was found that the log reduction of the tailing level of DRC was directly proportional to the log reduction of the number of large particles (> 60 microm) present in the effluent sample. Although the number of large particles was proportional to the coliform count at high UV dosage, the proportionality constant varied from 0.05 to 0.25, depending on the sample.

Subcellular dynamics of type II PKA in neurons

Protein kinase A (PKA) plays multiple roles in neurons. The localization and specificity of PKA are largely controlled by A-kinase anchoring proteins (AKAPs). However, the dynamics of PKA in neurons and the roles of specific AKAPs are poorly understood. We imaged the distribution of type II PKA in hippocampal and cortical layer 2/3 pyramidal neurons in vitro and in vivo. PKA was concentrated in dendritic shafts compared to the soma, axons, and dendritic spines. This spatial distribution was imposed by the microtubule-binding protein MAP2, indicating that MAP2 is the dominant AKAP in neurons. Following cAMP elevation, catalytic subunits dissociated from the MAP2-tethered regulatory subunits and rapidly became enriched in nearby spines. The spatial gradient of type II PKA between dendritic shafts and spines was critical for the regulation of synaptic strength and long-term potentiation. Therefore, the localization and activity-dependent translocation of type II PKA are important determinants of PKA function.

Myosin-dependent targeting of transmembrane proteins to neuronal dendrites

The distinct electrical properties of axonal and dendritic membranes are largely a result of specific transport of vesicle-bound membrane proteins to each compartment. How this specificity arises is unclear because kinesin motors that transport vesicles cannot autonomously distinguish dendritically projecting microtubules from those projecting axonally. We hypothesized that interaction with a second motor might enable vesicles containing dendritic proteins to preferentially associate with dendritically projecting microtubules and avoid those that project to the axon. Here we show that in rat cortical neurons, localization of several distinct transmembrane proteins to dendrites is dependent on specific myosin motors and an intact actin network. Moreover, fusion with a myosin-binding domain from Melanophilin targeted Channelrhodopsin-2 specifically to the somatodendritic compartment of neurons in mice in vivo. Together, our results suggest that dendritic transmembrane proteins direct the vesicles in which they are transported to avoid the axonal compartment through interaction with myosin motors.

Characterization and subcellular targeting of GCaMP-type genetically-encoded calcium indicators

Genetically-encoded calcium indicators (GECIs) hold the promise of monitoring [Ca²⁺] in selected populations of neurons and in specific cellular compartments. Relating GECI fluorescence to neuronal activity requires quantitative characterization. We have characterized a promising new genetically-encoded calcium indicator—GCaMP2—in mammalian pyramidal neurons. Fluorescence changes in response to single action potentials (17±10% ΔF/F [mean±SD]) could be detected in some, but not all, neurons. Trains of high-frequency action potentials yielded robust responses (302±50% for trains of 40 action potentials at 83 Hz). Responses were similar in acute brain slices from in utero electroporated mice, indicating that long-term expression did not interfere with GCaMP2 function. Membrane-targeted versions of GCaMP2 did not yield larger signals than their non-targeted counterparts. We further targeted GCaMP2 to dendritic spines to monitor Ca²⁺ accumulations evoked by activation of synaptic NMDA receptors. We observed robust ΔF/F responses (range: 37%–264%) to single spine uncaging stimuli that were correlated with NMDA receptor currents measured through a somatic patch pipette. One major drawback of GCaMP2 was its low baseline fluorescence. Our results show that GCaMP2 is improved from the previous versions of GCaMP and may be suited to detect bursts of high-frequency action potentials and synaptic currents in vivo.

Segmental bone tissue engineering by seeding osteoblast precursor cells into titanium mesh-coral composite scaffolds

The size and specific shape of bone grafts are important for jaw reconstruction. In this experiment, segmental bone grafts were engineered in a predetermined shape via seeding osteoblast precursor cells into titanium mesh-coral composite scaffolds. Titanium meshes were moulded into the shape of a column with length 12 mm and diameter 8mm. The column was filled with natural coral granules and the complex acted as a cell-seeding scaffold. About 4 x 10(7) osteoblast precursor cells in 200 microl cell-culture medium were seeded into each of six scaffolds and incubated in vitro for 2 days. Then, the composites were implanted subcutaneously into the backs of nude mice and incubated in vivo. Two months after implantation, the animals were killed and new bone formed in the scaffolds was investigated by gross inspection, X-ray examination, histological observation and mechanical testing. The results showed that newly formed tissue was red and presented the gross appearance of bone, and kept the original shape of the column. Titanium mesh was situated on the surface of the bone graft. An X-ray blocking shadow was observed in and around the titanium scaffolds; most of the coral granules had been absorbed. Histological observation demonstrated a large amount of new bone formed and integrated well with titanium mesh. Mechanical testing showed that new bone improved the mechanical property of the graft significantly. In conclusion, a titanium mesh-coral composite scaffold with osteoblast precursor cells is an efficient means to engineer segmental bone, possessing the desired shape and mechanical strength.

Performance of high-rate sludge digesters fed with sonicated sludge

A major limitation of anaerobic sludge digestion is the long hydraulic retention time (HRT) required for satisfactory stabilization which results in large digester size. This study explored a possibility of operating digesters at shortened HRTs by sonication pretreatment of secondary sludges. Four identical digesters designated D1, D2, D3 and D4 were fed with untreated and sludge sonicated at densities of 0.18 W/ml, 0.33 W/ml and 0.52 W/ml, respectively. All digesters were operated at three HRTs of 8-day, 4-day and 2-day. Comparing with the control digester (D1), total solids removal efficiencies improved by 12-19%, 17-36% and 20-39% in digesters D2, D3 and D4, respectively. The volatile solids removal was also increased by 11-21%, 17-33% and 19-36% in the respective digesters. The improved solids degradation corresponded with increase in biogas production by 1.4-2.5, 1.9-3.0 and 1.6-3.1 times, respectively. Increase in methane composition by 2-17% was also noted in all digesters fed with sonicated sludge. An analysis indicated that sonication pretreatment could enhance degradation of carbon, nitrogen and sulfur substances in the digestion. The study suggested that sonication of sludge is a possible pretreatment to shorten the digester operating HRT with improvement in solids degradation, biogas production and methane content. It can be deduced that to maintain a consistent solids loading at a desire performance, sludge digester with smaller size can be designed.

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.

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.

MICALs, a family of conserved flavoprotein oxidoreductases, function in plexin-mediated axonal repulsion

Members of the semaphorin family of secreted and transmembrane proteins utilize plexins as neuronal receptors to signal repulsive axon guidance. It remains unknown how plexin proteins are directly linked to the regulation of cytoskeletal dynamics. Here, we show that Drosophila MICAL, a large, multidomain, cytosolic protein expressed in axons, interacts with the neuronal plexin A (PlexA) receptor and is required for Semaphorin 1a (Sema-1a)-PlexA-mediated repulsive axon guidance. In addition to containing several domains known to interact with cytoskeletal components, MICAL has a flavoprotein monooxygenase domain, the integrity of which is required for Sema-1a-PlexA repulsive axon guidance. Vertebrate orthologs of Drosophila MICAL are neuronally expressed and also interact with vertebrate plexins, and monooxygenase inhibitors abrogate semaphorin-mediated axonal repulsion. These results suggest a novel role for oxidoreductases in repulsive neuronal guidance.

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.

[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.

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.

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.

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.

[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.

[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.

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.

[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.

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.

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.

[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.

[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.

[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.

[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.

[Relationship between elevated plasma endothelin-1 level and renal function in patients with diabetic nephropathy]

Plasma endothelin-1 (ET-1) level was measured with radioimmunoassay in 33 normal subjects and 92 patients with different stages of diabetic nephropathy, consisting of 35 cases of diabetes mellitus with normal urinary albumin excretion (DM), 22 cases of incipient diabetic nephropathy (IDN), 22 cases of overt diabetic nephropathy (ODN), 8 cases with azotemia (DNa) and 5 cases with uremia (DNu). The results showed that plasma ET-1 levels in DNa and DNu groups (30.24 +/- 1.93 ng/L and 36.38 +/- 3.62 ng/L respectively) were significantly higher than those in other groups (P < 0.05); ET-1 level in ODN group (20.50 +/- 0.93 ng/L) was significantly higher than those in DM and IDN groups (P < 0.001); ET-1 level in IDN group was also significantly higher than that in DM group (17.79 +/- 0.74 vs. 15.06 +/- 0.63 ng/L, P < 0.01); All the above values were significantly higher than that in normal subjects (7.08 +/- 0.22 ng/L) (P < 0.001). There was significant positive correlation between ET-1 level and HbA1c, systolic pressure, diastolic pressure, blood urea nitrogen, serum creatine, uAER and a significant negative correlation between ET-1 level and glomerular filtration rate. It is shown that progressive elevation of plasma ET-1 level is closely related with different stages of renal function impairment, suggesting strongly the role of ET-1 in the development and progression of diabetic nephropathy.

[Clinical significance on expression of the ras gene product P21 in human cervical carcinoma tissues]

Using MAB-P21 as a probe, the expression of gene product was studied by immunohistochemical ABC method, ABC staining of gel electrophoresis and ELISA quantitative analysis. The expression of P21 was detected in 107 cases of uterine cervix tissues, among which 70 were cervical carcinoma, 30 were chronic cervicitis and 7 normal cervix. Experimental results showed that obviously positive expression was noted in the specimens of cervical carcinoma and its positive rate was 72.8% (51/70). It was observed that the expression of P21 varied with grades of cell differentiation in cervical carcinoma. The level of P21 expression in high differentiated type was higher than that of the middle and low differentiated types. On the contrary, there was no detectable ras P21 in the normal cervix tissue and only 2 cases of cervicitis expressed positively (2/30). The results of ABC staining of electrophoresis showed that there was a P21 special staining band in cervical carcinoma tissues. And the contents of P21 protein were higher in cervical carcinoma than in normal cervix and cervicitis (t test, P less than 0.001). The expression of P21 was considerably enhanced in malignant tissue as compared with that in benign lesion.

[The status of human papillomavirus 16 DNA in the tissues of human esophagus carcinoma]

DNAs from 24 cases of human esophagus carcinoma and 24 cases of corresponding para-carcinoma tissues were detected by dot hybridization and Southern hybridization techniques using human papillomavirus (HPV) 16 type DNA as probe. The results indicated that the positive rate of the HPV 16 DNA hybridization was 50% (12/24) in esophagus carcinoma tissues, and 37% (9/24) in para-carcinoma tissues. The results of Southern hybridization showed obviously the positive hybridizing band in the zone of 7.2 kb in smear. It implied that HPV 16 DNA was possibly integrated into the tissue's DNA of esophagus carcinoma. In the fetal esophagus tissues as negative control, 3 cases out of 4 showed positive results. The significance has to be further investigated. This experiment has studied the status of HPV 16 type in the tissues of esophagus carcinoma and para-carcinoma at molecular level. This is just a study of the virus etiology of esophagus carcinoma.

[Studies on oncogene and its products of human nasopharyngeal carcinoma]

Oncogene of nasopharyngeal carcinoma (NPC) by means of external origin DNA transfection experiment and its gene products by immunohistochemical method have been studied. These DNAs were isolated from human primary poorly differentiated NPC tissues and were transfected into NIH/3T3 mouse fibroblasts to induce the foci of the morphologically transformed cells in the culture, while DNAs of normal placenta tissues failed to do so. The DNAs were extracted from the primary and secondary transformed cells to analyse human sequence with human Alu sequence probe. The human sequence has been detected in the DNAs of the primary and secondary transformed foci cells, while none of the human sequence was detected in the DNAs of the control. The results indicated that human transforming sequences had been integrated into transformed cells. The malignant properties of the transformed foci cells were evidenced by tumorigenic experiment of nude mice. The transformed foci cells were inoculated subcutaneously in the nude mice and induced fibrosarcoma in vivo. The tumorigenic rate was 87.5%. It was further demonstrated that DNAs from human NPC possessed carcinogenicity and induced malignant transformation. The primary result revealed that the transforming gene of NPC may be homologue to Ha-ras oncogene. The expression of Ha-ras gene products-p21 has been studied in human NPC tissues. The primary results showed a positive expression of p21 in human NPC tissues by immunohistochemical method. The positive rate was 90.4%.

[Study on molecular hybridization with biotin-labelled HPV 16 DNA probe in human cervical carcinoma]

Biotin-labelled human papillomavirus (HPV) 16 type DNA probe was prepared by the techniques of molecular biology. And dot hybridization technique was used to detect the HPV 16 homologous sequences in the tissues DNA of human cervical carcinoma. The results indicated that 16 cases out of 28 of the human cervical carcinoma tissues were positive. The positive rate was 57%. The other 4 cases of normal uterine cervix tissues were negative. Only 1 in 4 chronic cervicitis tissues showed positive. The HPV 16 plasmid DNA, as the positive control group, showed strong positive, while lambda-phage DNA was negative. The results have shown that the genome of the HPV actually exists in the tissue of the cervical carcinoma and that there is a close relationship between the cervical carcinoma and HPV infection. This experiment adopted the Biotin-labelled HPV 16 DNA probe. And it may provide us with a quick and sensitive method for investigation of the infection of HPV and its role in the carcinogenesis of cervical carcinoma.