Human Breast Extracellular Matrix Microstructures and Protein Hydrogel 3D Cultures of Mammary Epithelial Cells

Simple Summary

Human breast tissue extracellular matrix (ECM) is a microenvironment essential for the survival and biological activities of mammary epithelial cells. The ECM structural features of human breast tissues remain poorly defined. In this study, we identified the structural and mechanical properties of human normal breast and invasive ductal carcinoma tissue ECM using histological methods and atomic force microscopy. Additionally, a protein hydrogel was generated using human breast tissue ECM and defined for its microstructural features using immunofluorescence imaging and machine learning. Furthermore, we examined the three-dimensional growth of normal mammary epithelial cells or breast cancer cells cultured on the ECM protein hydrogel, where the cells exhibited biological phenotypes like those seen in native breast tissues. Our data provide novel insights into cancer cell biology, tissue microenvironment mimicry and engineering, and native tissue ECM-based biomedical and pharmaceutical applications.

Abstract

Tissue extracellular matrix (ECM) is a structurally and compositionally unique microenvironment within which native cells can perform their natural biological activities. Cells grown on artificial substrata differ biologically and phenotypically from those grown within their native tissue microenvironment. Studies examining human tissue ECM structures and the biology of human tissue cells in their corresponding tissue ECM are lacking. Such investigations will improve our understanding about human pathophysiological conditions for better clinical care. We report here human normal breast tissue and invasive ductal carcinoma tissue ECM structural features. For the first time, a hydrogel was successfully fabricated using whole protein extracts of human normal breast ECM. Using immunofluorescence staining of type I collagen (Col I) and machine learning of its fibrous patterns in the polymerized human breast ECM hydrogel, we have defined the microstructural characteristics of the hydrogel and compared the microstructures with those of other native ECM hydrogels. Importantly, the ECM hydrogel supported 3D growth and cell-ECM interaction of both normal and cancerous mammary epithelial cells. This work represents further advancement toward full reconstitution of the human breast tissue microenvironment, an accomplishment that will accelerate the use of human pathophysiological tissue-derived matrices for individualized biomedical research and therapeutic development.

Distinct phenotypes of cancer cells on tissue matrix gel

BACKGROUND

Breast cancer cells invading the connective tissues outside the mammary lobule or duct immerse in a reservoir of extracellular matrix (ECM) that is structurally and biochemically distinct from that of their site of origin. The ECM is a spatial network of matrix proteins, which not only provide physical support but also serve as bioactive ligands to the cells. It becomes evident that the dimensional, mechanical, structural, and biochemical properties of ECM are all essential mediators of many cellular functions. To better understand breast cancer development and cancer cell biology in native tissue environment, various tissue-mimicking culture models such as hydrogel have been developed. Collagen I (Col I) and Matrigel are the most common hydrogels used in cancer research and have opened opportunities for addressing biological questions beyond the two-dimensional (2D) cell cultures. Yet, it remains unclear whether these broadly used hydrogels can recapitulate the environmental properties of tissue ECM, and whether breast cancer cells grown on CoI I or Matrigel display similar phenotypes as they would on their native ECM.

METHODS

We investigated mammary epithelial cell phenotypes and metabolic profiles on animal breast ECM-derived tissue matrix gel (TMG), Col I, and Matrigel. Atomic force microscopy (AFM), fluorescence microscopy, acini formation assay, differentiation experiments, spatial migration/invasion assays, proliferation assay, and nuclear magnetic resonance (NMR) spectroscopy were used to examine biological phenotypes and metabolic changes. Student's t test was applied for statistical analyses.

RESULTS

Our data showed that under a similar physiological stiffness, the three types of hydrogels exhibited distinct microstructures. Breast cancer cells grown on TMG displayed quite different morphologies, surface receptor expression, differentiation status, migration and invasion, and metabolic profiles compared to those cultured on Col I and Matrigel. Depleting lactate produced by glycolytic metabolism of cancer cells abolished the cell proliferation promoted by the non-tissue-specific hydrogel.

CONCLUSION

The full ECM protein-based hydrogel system may serve as a biologically relevant model system to study tissue- and disease-specific pathological questions. This work provides insights into tissue matrix regulation of cancer cell biomarker expression and identification of novel therapeutic targets for the treatment of human cancers based on tissue-specific disease modeling.

Dynamic Impedance Monitoring for Large Diameter Vessel Sealing Using Bipolar Electrosurgery

Vessel sealing using bipolar electrosurgery is becoming a common practice in modern operating rooms. Despite all the advantages such as faster operation, less bleeding, and shorter postsurgery recovery time, side effects including sticking, charring, and rebleeding still occur, leading to increased surgery time and sometimes fatal complications. Tissue impedance during the electrosurgical process has been used to determine the electrical power of the process. However, little has been done to understand the dynamic tissue impedance and its effectiveness in monitoring the vessel sealing process. Moreover, the samples used in previous studies all had small diameters of 2–5 mm. In this study, an experimental setup was developed to perform vessel sealing tests using large-diameter blood vessel samples with mimicking blood flow. The tissue impedance during the heating process was obtained. Burst pressures after sealing were measured. A finite element simulation model was developed to understand the dynamic impedance behavior. It is seen that the tissue impedance increases rapidly in the beginning of the heating process and remains at a level that is several orders of magnitude higher than the initial value. This rapid impedance increase indicates protein denaturing, thus can be used to monitor the electrosurgical vessel sealing process. An impedance-based monitoring algorithm was developed, with which a burst pressure at least twice the normal human systolic blood pressure was achieved.

A Feasibility Study of an Extrusion-Based Fabrication Process for Personalized Drugs

Developing a high-efficiency manufacturing system for personalized medicine plays an important role in increasing the feasibility of personalized medication. The purpose of this study is to investigate the feasibility of a new extrusion-based fabrication process for personalized drugs with a faster production rate. This process uses two syringe pumps with a coaxial needle as an extruder, which extrudes two materials with varying ratios into a capsule. The mixture of hydrogel, polyethylene glycol (PEG), hydroxypropyl methylcellulose, poly acrylic acid and the simulated active pharmaceutical ingredient, Aspirin, was used. To validate the method, samples with different ratios of immediate release (IR) and sustained release (SR) mixtures were fabricated. The results of a dissolution test show that it is feasible to control the release profile by changing the IR and SR ratio using this fabrication setup. The fabrication time for each capsule is about 20 seconds, which is significantly faster than the current 3D printing methods. In conclusion, the proposed fabrication method shows a clear potential to step toward the feasibility of personalized medication.

Determination of Tissue Thermal Conductivity as a Function of Thermal Dose and Its Application in Finite Element Modeling of Electrosurgical Vessel Sealing

OBJECTIVE

Electrosurgical vessel sealing is a process commonly used to control bleeding during surgical procedures. Finite element (FE) modeling is often performed to obtain a better understanding of thermal spread during this process. The accuracy of the FE model depends on the implemented material properties. Thermal conductivity is one of the most important properties that affect temperature distribution. The goal of this study is to determine the tissue thermal conductivity as a function of thermal dose. Methods: We developed an iterative approach to correlating tissue thermal conductivity to more accurately calculated thermal dose, which cannot be experimentally measured. The resulting regression model was then implemented into an electrosurgical vessel sealing FE model to examine the accuracy of this FE model. Results: The results show that with the regression model, more reasonable temperature and thermal dose prediction can be achieved at the center of the sealed vessel tissue. The resulting electrical current and impedance from the FE model match with the experimental results. Conclusion: The developed approach can be used to determine the correlation between thermal dose and thermal conductivity. Describing the thermal conductivity as a function of thermal dose allows modeling of irreversible changes in tissue properties. Significance: By having a more accurate temperature estimation at the center of the sealed vessel, more insight is provided into how the tissue reacts during the vessel sealing process.

[Comparison of the NoSAS score with four different questionnaires as screening tools for obstructive sleep apnea-hypopnea syndrome]

Objective: To evaluate the clinical utility of the NoSAS score in the screening of patients with obstructive sleep apnea-hypopnea syndrome(OSAHS), and to compare the performance of the NoSAS score with other tools including Epworth Sleepiness Scale(ESS), STOP, STOP-Bang(SBQ) and Berlin questionnaires. Methods: A total of 444 consecutive patients(328 males and 116 females) with suspected OSAHS who underwent an overnight polysomnography(PSG) were recruited into this study. Five questionnaires including the NoSAS score, ESS, STOP, SBQ and Berlin were completed. Based on the severity of OSAHS which was determined by apnea-hypopnea index(AHI), the patients were classified into 4 groups: normal(<5 events/h), mild(5-15 events/h), moderate(15-30 events/h) and, severe (≥30 events/h) OSA.Sensitivity, specificity, positive predictive values, negative predictive values and the area under the receiver operating characteristics curve of 5 questionnaires were calculated. Results: With AHI≥5 events/h as the standard diagnosis of OSAHS, the NoSAS score and SBQ questionnaire showed a moderate performance, with the NoSAS score having the largest area under the ROC curve(0.753, P<0.001), followed by the SBQ questionnaire (0.727, P<0.001). The performance of the ESS, Berlin, and the STOP questionnaire was not high. Using mild moderate-severe(≥5 events/h), moderate-severe(≥15 events/h), and severe(≥30 events/h)OSAHS as cutoffs, NoSAS had the highest specificity and positive predictive values(80.2% and 88%, 72% and 69.8%, 66.3% and 50.5%), and the sensitivity and negative predictive values were (51.5% and 36.9%, 56.5% and 59.1%, 66.3% and 74.2%) .SBQ had the highest sensitivity and the negative predictive values(80.2% and 88%, 72% and 69.8%, 66.3% and 50.5%), and the specific and positive predictive values were (45.7% and 81.0%, 39.1% and 61.9%, 34.8% and 44.4%). The NoSAS score ≥ 7 had higher sensitivity and negative predictive value(75.0% and 47.1%, 78.1% and 66.5%, 82.7% and 81.9%)than the NoSAS socre ≥ 8. With AHI≥5 events/h as the standard diagnosis of OSAHS, the NoSAS score and the SBQ questionnaire had a higher accuracy than the other 3 questionnaires as screening questionnaires for diagnosing OSAHS, and the value of DOR were 4.298 and 3.758 respectively. Conclusions: The NoSAS score and the SBQ questionnaire have a moderate performance in diagnosing OSAHS. The NoSAS score is a new screening tool, and it is similar to the SBQ questionnaire, being also simple and effective. While the SBQ questionnaire is more widely used, it is necessary to further evaluate the diagnostic value of NoSAS score.

[Correlation between peripheral venous oxygen saturation and hemodynamic parameters in patients with pulmonary hypertension]

Objective: To investigate the correlation of peripheral venous oxygen saturation (SpvO(2)) with mixed venous oxygen saturation (SvO(2)), pulmonary vascular resistance (PVR) and cardiac index (CI) in patients with pulmonary hypertension (PH), in order to predict these parameters using SpvO(2) and assess the prognosis of patients. Methods: Hospitalized patients diagnosed with PH by right heart catheterization in the Guangzhou Institute of Respiratory Diseases from July 2015 to October 2016 were retrospectively analyzed. Parameters during the right heart catheterization, including SvO(2,)SpvO(2,)cardiac output (CO) and mean pulmonary arterial pressure (mPAP) were recorded, while CI, PVR and other parameters were indirectly calculated. The correlation between SpvO(2) and SvO(2,)CO, CI, mPAP, PVR and other parameters were respectively analyzed and compared between groups. Results: A total of 77 PH patients were selected, which comprised of 39 males and 38 females. The results revealed that SpvO(2) was correlated positively with SvO(2,)CI and PaO(2) (P<0.05), but negatively with PVR, total pulmonary resistance (TPR), systemic vascular resistance, right atrial diameter and right ventricular diameter (P<0.05). In the group with SpvO(2) <65%, the dilation of the right atrium and right ventricle was more significant, the WHO heart function grade was worse, CI, systemic systolic pressure and mean systemic pressure were lower, and PVR and TPR were higher, as compared to those in the group with SpvO(2) ≥65%. (P<0.05). Conclusions: There was good consistency between SpvO(2) and SvO(2). Furthermore, SpvO(2) could indirectly reflect the CI, PVR and changes in right heart structure of PH patients, providing reference for the clinical prediction of CI and PVR, as well as the prognosis of PH patients, through the use of SpvO(2). Low SpvO(2) indicated a severe condition and poor prognosis.

Porcine Breast Extracellular Matrix Hydrogel for Spatial Tissue Culture

Porcine mammary fatty tissues represent an abundant source of natural biomaterial for generation of breast-specific extracellular matrix (ECM). Here we report the extraction of total ECM proteins from pig breast fatty tissues, the fabrication of hydrogel and porous scaffolds from the extracted ECM proteins, the structural properties of the scaffolds (tissue matrix scaffold, TMS), and the applications of the hydrogel in human mammary epithelial cell spatial cultures for cell surface receptor expression, metabolomics characterization, acini formation, proliferation, migration between different scaffolding compartments, and in vivo tumor formation. This model system provides an additional option for studying human breast diseases such as breast cancer.

An experimental study and finite element modeling of head and neck cooling for brain hypothermia

Reducing brain temperature by head and neck cooling is likely to be the protective treatment for humans when subjects to sudden cardiac arrest. This study develops the experimental validation model and finite element modeling (FEM) to study the head and neck cooling separately, which can induce therapeutic hypothermia focused on the brain. Anatomically accurate geometries based on CT images of the skull and carotid artery are utilized to find the 3D geometry for FEM to analyze the temperature distributions and 3D-printing to build the physical model for experiment. The results show that FEM predicted and experimentally measured temperatures have good agreement, which can be used to predict the temporal and spatial temperature distributions of the tissue and blood during the head and neck cooling process. Effects of boundary condition, perfusion, blood flow rate, and size of cooling area are studied. For head cooling, the cooling penetration depth is greatly depending on the blood perfusion in the brain. In the normal blood flow condition, the neck internal carotid artery temperature is decreased only by about 0.13°C after 60min of hypothermia. In an ischemic (low blood flow rate) condition, such temperature can be decreased by about 1.0°C. In conclusion, decreasing the blood perfusion and metabolic reduction factor could be more beneficial to cool the core zone. The results also suggest that more SBC researches should be explored, such as the optimization of simulation and experimental models, and to perform the experiment on human subjects.

Segregation analysis of microsatellite (SSR) markers in sugarcane polyploids

No information is available on segregation analysis of DNA markers involving both pollen and self-progeny. Therefore, we used capillary electrophoresis- and fluorescence-based DNA fingerprinting together with single pollen collection and polymerase chain reaction (PCR) to investigate simple sequence repeat (SSR) marker segregation among 964 single pollens and 288 self-progenies (S1) of sugarcane cultivar LCP 85-384. Twenty SSR DNA fragments (alleles) were amplified by five polymorphic SSR markers. Only one non-parental SSR allele was observed in 2392 PCRs. SSR allele inheritance was in accordance with Mendelian laws of segregation and independent assortment. Highly significant correlation coefficients were found between frequencies of observed and expected genotypes in pollen and S1 populations. Within the S1 population, the most frequent genotype of each SSR marker was the parental genotype of the same marker. The number of genotypes was higher in pollen than S1 population. PIC values of the five SSR markers were greater in pollen than S1 populations. Eleven of 20 SSR alleles (55%) were segregated in accordance with Mendelian segregation ratios expected from pollen and S1 populations of a 2n = 10x polyploid. Six of 20 SSR alleles were segregated in a 3:1 (presence:absence) ratio and were simplex markers. Four and one alleles were segregated in 77:4 and 143:1 ratios and considered duplex and triplex markers, respectively. Segregation ratios of remaining alleles were unexplainable. The results provide information about selection of crossing parents, estimation of seedling population optimal size, and promotion of efficient selection, which may be valuable for sugarcane breeders.

Establishment of a prediction model for the miRNA-based heading date characteristics of rice in the booting stage

Rice (Oryza sativa L.) is one of the most important food crops in the world. In Taiwan, due to the warm climate, there are two harvests annually. However, the yield and quality of rice can vary between each crop season in any given year. Previous reports have shown that microRNAs (miRNAs) play a crucial role in many developmental and physiological processes in plants. In this study, the heading date characteristics of 167 rice cultivars from the second crop season were recorded, and 27 rice cultivars were selected for preliminary microarray analysis. A total of 14 miRNAs from different heading date characteristics in 21 cultivars were selected based on significant differences in their expression profiles. Using a correlation analysis between the heading date and selected miRNA expression obtained from real-time polymerase chain reaction (PCR) assays, we developed a heading date prediction model. The model includes nine miRNA genes with corresponding R2 values of 0.8. To confirm the model, a real-time PCR analysis was performed on an additional 27 rice cultivars and we found the model predicted the heading date with accuracy. Therefore, the developed prediction may be useful in further studies aimed at confirming the reliability of the use of miRNA in molecular breeding and to increase the selection efficiency of rice cultivars and breeding.

Bipolar electrosurgical vessel-sealing device with compressive force monitoring

Bipolar electrosurgical vessel sealing is commonly used in surgery to perform hemostasis. The electrode compressive force is demonstrably an important factor affecting the vessel seal burst pressure, an index of the seal quality. Using a piezoresistive force sensor attached to the handle of a laparoscopic surgical device, applied handle force was measured and used to predict the electrosurgical vessel compressive force and the pressure at the electrode. The sensor enables the monitoring of vessel compressive force during surgery. Four levels of compressive force were applied to seal three types of porcine vessels (carotid artery, femoral artery, and jugular vein). The burst pressure of the vessel seal was tested to evaluate the seal quality. Compressive pressure was found to be a statistically significant factor affecting burst pressure for femoral arteries and jugular veins. Vessels sealed with low compressive pressure (<300 kPa) have a higher failure rate (burst pressure<100 mm Hg) than vessels sealed with high compressive pressure. An adequate compressive force is required to generate the compressive pressure needed to form a seal with high burst pressure. A laparoscopic surgical device with compressive force monitoring capability can help ensure adequate compressive pressure, vessel burst pressure, and quality of seal.

Study of insertion force and deformation for suturing with precurved NiTi guidewire

This research presents an experimental study evaluating stomach suturing using a precurved nickel-titanium (NiTi) guidewire for an endoscopic minimally invasive obesity treatment. Precise path planning is critical for accurate and effective suturing. A position measurement system utilizing a hand-held magnetic sensor was used to measure the shape of a precurved guidewire and to determine the radius of curvature before and after suturing. Ex vivo stomach suturing experiments using four different guidewire tip designs varying the radius of curvature and bevel angles were conducted. The changes in radius of curvature and suturing force during suturing were measured. A model was developed to predict the guidewire radius of curvature based on the measured suturing force. Results show that a small bevel angle and a large radius of curvature reduce the suturing force and the combination of small bevel angle and small radius of curvature can maintain the shape of guidewire for accurate suturing.

Optimal needle design for minimal insertion force and bevel length

This research presents a methodology for optimal design of the needle geometry to minimize the insertion force and bevel length based on mathematical models of cutting edge inclination and rake angles and the insertion force. In brachytherapy, the needle with lower insertion force typically is easier for guidance and has less deflection. In this study, the needle with lancet point (denoted as lancet needle) is applied to demonstrate the model-based optimization for needle design. Mathematical models to calculate the bevel length and inclination and rake angles for lancet needle are presented. A needle insertion force model is developed to predict the insertion force for lancet needle. The genetic algorithm is utilized to optimize the needle geometry for two cases. One is to minimize the needle insertion force. Using the geometry of a commercial lancet needle as the baseline, the optimized needle has 11% lower insertion force with the same bevel length. The other case is to minimize the bevel length under the same needle insertion force. The optimized design can reduce the bevel length by 46%. Both optimized needle designs were validated experimentally in ex vivo porcine liver needle insertion tests and demonstrated the methodology of the model-based optimal needle design.

Analysis of sequence diversity through internal transcribed spacers and simple sequence repeats to identify Dendrobium species

The Orchidaceae is one of the largest and most diverse families of flowering plants. The Dendrobium genus has high economic potential as ornamental plants and for medicinal purposes. In addition, the species of this genus are able to produce large crops. However, many Dendrobium varieties are very similar in outward appearance, making it difficult to distinguish one species from another. This study demonstrated that the 12 Dendrobium species used in this study may be divided into 2 groups by internal transcribed spacer (ITS) sequence analysis. Red and yellow flowers may also be used to separate these species into 2 main groups. In particular, the deciduous characteristic is associated with the ITS genetic diversity of the A group. Of 53 designed simple sequence repeat (SSR) primer pairs, 7 pairs were polymorphic for polymerase chain reaction products that were amplified from a specific band. The results of this study demonstrate that these 7 SSR primer pairs may potentially be used to identify Dendrobium species and their progeny in future studies.

Comparison of thermal coagulation profiles for bipolar forceps with different cooling mechanisms in a porcine model of spinal surgery

Background:

Coagulation accomplished using bipolar forceps is common in neurosurgery. Control of thermal spread from the forceps tips into surrounding neural tissues is a persistent concern, as neural tissues are especially vulnerable to heat injury. The purpose of our investigation was to compare the efficacy of cooling mechanisms for four different bipolar forceps and to understand thermal spread when coagulating vessels on the spinal cord.

Methods:

Immediately following euthanasia, the dura mater of an ex vivo porcine model was opened to expose vessels on the spinal cord for coagulation. Temperature profiles were measured at generator power of 25 W and at fixed 5-second activation times. The bipolar forceps used in this study included regular stainless steel, titanium, heat-pipe embedded, and SILVERGlide forceps. Temperature was measured by micro-thermistor at the midpoint between the bipolar tips, and 1 and 2 mm away from the midpoint along the centerline. Statistical analysis was performed to evaluate temperature differences.

Results:

Temperature profiles indicated that heat-pipe embedded forceps create the least amount of temperature increase and the highest normalized temperature decreasing slope after activation. The decreasing slope of SILVERGlide forceps is slightly higher than that of regular stainless steel forceps.

Conclusions:

Bipolar forceps incorporating either heat-pipe embedded technology or SILVERGlide coating can effectively limit excessive thermal spread, thus decreasing potential injury to adjacent tissues when compared with standard stainless steel and titanium bipolar forceps. Of the two, heat-pipe embedded technology appeared safest, having better cooling efficiency at higher temperature.

Thermoelectrical modeling of bipolar coagulation on posterior spinal artery in a porcine spinal surgery model

The primary objective of our study was to develop a thermoelectrical model with both solid and liquid phases to calculate tissue temperature during bipolar coagulation of a posterior spinal artery on the spinal cord. Control of thermal spread caused by coagulation is a concern in spinal surgery. This model utilizes a nonisothermal flow to account for the heat transfer due to the movement of cerebrospinal fluid that is induced by electrical field and temperature gradient. The model is validated by in situ temperature measurements on a porcine spinal cord model. The maximum error for tissue temperature of this model is 12.6%, and the overall average error is 4.2%. The lesional region (>50°C) is identified to be as wide as 5 mm, and thermal dose cumulative equivalent minutes at 43°C (CEM 43) is also calculated with this model. The incorporation of nonisothermal flow has been shown to be crucial in order to accurately predict thermal dose in tissue. The developed model can be further used to establish a guideline for the use of bipolar coagulation.

Electrosurgical vessel sealing tissue temperature: experimental measurement and finite element modeling

The temporal and spatial tissue temperature profile in electrosurgical vessel sealing was experimentally measured and modeled using finite element modeling (FEM). Vessel sealing procedures are often performed near the neurovascular bundle and may cause collateral neural thermal damage. Therefore, the heat generated during electrosurgical vessel sealing is of concern among surgeons. Tissue temperature in an in vivo porcine femoral artery sealed using a bipolar electrosurgical device was studied. Three FEM techniques were incorporated to model the tissue evaporation, water loss, and fusion by manipulating the specific heat, electrical conductivity, and electrical contact resistance, respectively. These three techniques enable the FEM to accurately predict the vessel sealing tissue temperature profile. The averaged discrepancy between the experimentally measured temperature and the FEM predicted temperature at three thermistor locations is less than 7%. The maximum error is 23.9%. Effects of the three FEM techniques are also quantified.

Spark erosion: a high production rate method for producing Bi(0.5)Sb(1.5)Te3 nanoparticles with enhanced thermoelectric performance

We report a new 'spark erosion' technique for producing high-quality thermoelectric nanoparticles at a remarkably high rate and with enhanced thermoelectric properties. The technique was utilized to synthesize p-type Bi(0.5)Sb(1.5)Te(3) nanoparticles with a production rate as high as 135 g h(-1), using a relatively small laboratory apparatus and low energy consumption. The compacted nanocomposite samples made from these nanoparticles exhibit a well-defined, 20-50 nm size nanograin microstructure, and show an enhanced figure of merit, ZT, of 1.36 at 360 K. Such a technique is essential for providing inexpensive, oxidation-free nanoparticles which are required for the fabrication of high performance thermoelectric devices for power generation from waste heat, and for refrigeration.

Transplantation of Schwann cells differentiated from adipose-derived stem cells modifies reactive gliosis after contusion brain injury in rats

This study investigated whether transplantation of Schwann cells differentiated from adipose-derived stem cells (ADSC-SCs) of rats could promote functional improvement after contusion brain injury, with a focus on the effect on reactive gliosis. ADSCs were isolated and expanded from groin adipose tissue of Sprague-Dawley rats and then differentiated into Schwann cells. ADSCSCs were transplanted into the contused rat brain. Immunofluorescence and Western blotting were used to analyse reactive gliosis, and locomotor function of the rats was assessed. Hemiparalysed rats transplanted with ADSC-SCs showed significant locomotor function recovery compared with rats transplanted with undifferentiated ADSCs or control rats injected with medium alone. Transplanted ADSC-SCs significantly reduced glial scar formation and neurocan protein levels compared with transplanted undifferentiated ADSCs. In conclusion, transplantation of ADSC-SCs can effectively promote locomotor functional recovery and reduce reactive gliosis after contusion brain injury in rats.

Assessment of hemodynamics properties of a new-type artificial heart valve prosthesis using catheterization and echocardiography

OBJECTIVE

The objectives of this study were to assess the hemodynamic properties of the newly developed artificial heart valve prosthesis experimentally in laboratory simulation, in an animal model, and clinically in a human model and to compare the results measured by catheterization and echocardiography.

METHODS

(1) Laboratory simulation. The prosthesis was tested using a pulsatile flow simulator in the aortic position. Hydrodynamics parameters were automatically analyzed through a custom-designed data processing program. (2) Animal experiment. Six sheep subjected to mitral replacement with 21-mm-valve prosthesis were measured by open cardiac catheterization intraoperatively. Doppler echocardiography and open cardiac catheterization under dobutamine stress were performed in two sheep subjected to implantation 2.5 years ago. (3) Clinical patient observation. Observations were carried out on 14 patients with aortas replacement and 10 patients with bicuspid replacement using both doppler echocardiography and open cardiac catheterization.

RESULTS

(1) Laboratory simulation. The results showed that the value of the transvalvular gradient (DeltaP) decreased with the increase of heart rate, and the values were not greater that 10 mm Hg at any given tissue annulus diameter. (2) Animal experiment. The mean DeltaP value of the six sheep was 5.2 +/- 1.7 mm Hg intraoperatively, while the corresponding DeltaP value of the two sheep 2.5 years after implantation was 6.1 +/- 0.3 mm Hg measured by open cardiac catheterization. (3) Clinical patient observation. The mean DeltaP values in the aortic position measured by catheterization and echocardiography were 6.26 approximately 4.10 and 9.42 approximately 7.48 mm Hg, respectively. The gradients in the mitral position were 2.10 approximately 1.9 and 5.28 approximately 4.10 mm Hg, respectively.

CONCLUSIONS

The results demonstrate that the new-type bileaflet heart valve prosthesis only generates a relatively low transvalvar gradient and thus has good hemodynamic properties.

Giant Solitary Fibrous Tumor of the Pleura

A 42-year-old woman developed an exceedingly big, solitary fibrous tumor of the pleura (SFTP) that occupied the whole right thorax. She complained of worsening dyspnea as her right lung was completely compressed and the mediastinum was pushed to the left side. A successful resection was performed; after reassembly, the tumor measured 20 cm x 22 cm x 30 cm and weighed 5.2 kg. The squashed right lung reached 60 % re-expansion postoperatively and the patient is in good health at 38 months' follow-up.

Effects of methylprednisolone and aprotinin on phospholipase D activity of leukocytes in systemic inflammatory response induced by cardiopulmonary bypass

AIM

To investigate the role of leukocyte phospholipase D (PLD) in systemic inflammatory response induced by cardiopulmonary bypass (CPB) and the effects of methylprednisolone and aprotinin on leukocyte PLD activity.

METHODS

Forty-two patients who received CPB open heart surgery were divided into 3 groups: methylprednisolone group, aprotinin group, and control group. Arterial blood (10 mL) was collected for assay of leukocyte PLD activity, myeloperoxidase (MPO) activity, and CD11b expression at 8 different time points in perioperative period. Plasma IL-6, IL-8, and C-reactive protein levels were also determined.

RESULTS

At the time point of ascending aorta declamped, leukocyte PLD activity for control group was (18 +/- 8) nmol choline . h-1 . mg-1, which was higher than that of pre-CPB (P < 0.01); the PLD activity for methylprednisolone group was (10 +/- 6) nmol choline . h-1 . mg-1 that was lower than control (P < 0.05), while it had no statistical difference compared with that of pre-CPB. In methylprednisolone group, PLD activity elevation was postponed to the time point of CPB stopped. There was no statistical difference in PLD activity between aprotinin group and control (P > 0.05). After administration of methylprednisolone or aprotinin, leukocyte CD11b expression, plasma IL-6, IL-8, C-reactive protein levels, and MPO activity decreased by different extent.

CONCLUSION

Leukocyte PLD activity was elevated significantly in systemic inflammatory response induced by CPB and methylprednisolone partially blunted the CPB-induced inflammatory response by inhibiting PLD activity.

[Genetic engineering sugarcane: potential, current status and prospects]

The literatures on potential of genetic engineering in sugarcane, transformation method and its efficiency, effects of promoter and selectable marker on gene expression and on identification of transformant, and achievement of genetic engineering in sugarcane were reviewed. Directions of further research were also suggested.

Structural properties of lanthanide and actinide compounds within the plane wave pseudopotential approach

We show that plane wave ultrasoft pseudopotential methods readily extend to the calculation of the structural properties of lanthanide and actinide containing compounds. This is demonstrated through a series of calculations performed on UO, UO2, UO3, U3O8, UC2, alpha-CeC2, CeB6, CeSe, CeO2, NdB6, TmOI, LaBi, LaTiO3, YbO, and elemental Lu.

Open-heart surgery in 48 patients via a small right anterolateral thoracotomy

To limit the trauma to the chest and to achieve a pleasing cosmetic result, we used 2 types of right anterolateral thoracotomy in 48 patients who required open-heart surgery: 1 was a curved incision along the lower edge of the right breast in women with developed breasts; the other was a slanted incision for men and children. These surgical procedures took place between July 1996 and November 1997. Intraoperatively, a right atriotomy was used to repair 11 atrial septal defects and 11 ventricular septal defects, 2 combined atrial and ventricular septal defects, 1 case of a single atrium, and 1 partial atrioventricular canal. A right ventricular outflow tract incision was used to repair 7 ventricular septal defects and 7 ruptured aortic sinus aneurysm. A combination of a right atriotomy and right ventricular outflow tract incision was used for 2 repairs of combined atrial and ventricular septal defects, 3 radical corrections of tetralogy of Fallot, and 2 radical corrections of trilogy of Fallot. A combined right and interatrial septal incision was used for 6 mitral valve replacements and 1 mitral valvuloplasty. Smooth bypass cannulation and satisfactory intracardiac exposure were achieved with the right anterolateral thoracotomy. There was no complication or mortality directly related to the incision. We believe that the right anterolateral thoracotomy is safer and more effective than the median sternotomy for many common congenital and acquired heart diseases. The thoracotomy causes less trauma and results in a cosmetic appearance that is more acceptable to the patient.

Simultaneous determination of benzene, toluene, ethylbenzene, and xylenes in urine by thermal desorption-gas chromatography

The determination of metabolites of benzene, toluene, ethylbenzene, and xylenes in urine has been used to assess human exposure to these compounds. The analyses of urine samples for these metabolites are tedious and time consuming. The determination of unmetabolized individual compounds in urine has been studied previously with some success. A simultaneous determination of several unmetabolized VOC compounds in urine by thermal desorption-gas chromatography was conducted to assess the exposure of smokers and nonsmokers to these compounds. The method of thermal desorption-GC was sensitive enough to detect a significant difference in exposure levels due to the contribution of light smoking in the environmentally-exposed group.

[Valvuloplasty of rheumatic tricuspid valve disease]

This paper reports 49 cases with rheumatic tricuspid lesions underwent tricuspid valvuloplasty. Tricuspid stenosis was in 26, and combined with incompetence in 23. Posterior-septal, anterior-septal, and anterior-posterior commissural fusions were 9, 7, and 5 cases respectively. Tricuspid repair was used in all cases, fused chordae, papillary muscles and valvular commissures were each divided, then De Vaga's or Kay's annuloplasty was performed to correct the residual regurgitation. The associated procedures included DVR in 33, MVR in 15, and AVR in 1. Hospital death was 3 cases. All early survivors were followed up (2 months to 7 yrs, mean 4.2 yrs). There was no late death, heart functional class I was in 34, class II in 10 and class III in 2. Echocardiography performed 6 months postoperatively, showed no tricuspid regurgitation was in 38, moderate regurgitation in 8, and the right atrial volume decreased in various degrees. The principles and the methods of tricuspid valve repair in patients with rheumatic tricuspid lesions were discussed.

[Anticoagulant management of patients with cardiac valve prostheses]

This article reports the methods and results of anticoagulant management in 653 patients with China-made Björk-Shiley mode Tilting Disc Cardiac Valve Prostheses. The total incidence of thromboembolic complications and valve thrombosis is 0.98 per 100 patient-years during the anticoagulation. The incidence of anticoagulant-related hemorrhage is 1.86 per 100 patient-years. In the anticoagulant period, 61 surgical operations were performed on 58 patients. The results showed that anticoagulant can be maintained in minor, superficial operations where blood ooze can be arrested by compression, temporarily discontinued in elective operations, and reversed abruptly by injecting Vitamin K1 in urgent operations. In addition we handled the contradictions between anticoagulant therapy and menses, contraceptive, pregnancy or delivery (29 patients) for 303 female patients favorably. We conclude that our methods gave excellent results, and were reasonable and practicable.