Toward re-expressing tumor suppresor gene maspin in breast cancer.
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Animals↗
Biomedical subjects
Ming Zhang
Publications and source records attributed to Ming Zhang.
The investing layer of the deep cervical fascia does not exist between the sternocleidomastoid and trapezius muscles.
OBJECTIVE: We sought to describe the 3-dimensional organization of connective tissues in the suboccipital region. STUDY DESIGN AND SETTING: We conducted a sectional anatomic investigation with the use of E12 sheet plastination. SUBJECTS: Six human adult cadavers (2 male and 4 female; age range, 54 to 86 years) were used in this study. Five of them were sectioned as 2.5-mm-thick coronal (1 cadaver), transverse (2 cadavers), or sagittal (2 cadavers) sections. RESULTS: No aggregation of fibrous connective tissue was seen between the sternocleidomastoid and trapezius muscles. The intervening space was fully occupied by fatty tissue that was indistinguishable from the subcutaneous tissue. CONCLUSIONS: The investing layer of the deep cervical fascia is incomplete so that the carotid sheath is directly exposed to the subcutaneous tissue via a gap between the sternocleidomastoid and trapezius muscle. SIGNIFICANCE: This anatomic feature should be considered when designing a minimally invasive endoscopic approach to the carotid sheath and the surrounding deep cervical structures.
Aged↗
Mechanism of the positive inotropic effect of lysophosphatidic acid in rat heart.
BACKGROUND: Lysophosphatidic acid, a bioactive phospholipid, is mainly released from the activated platelets. The concentration of lysophosphatidic acid in serum is elevated under conditions such as ischemia, hypertension, and thrombosis; however, its effect on cardiac function, as well as the mechanisms of its action, have not been fully understood. METHODS AND RESULTS: Cardiovascular effects of lysophosphatidic acid were studied in vivo in rats as well as in vitro by using the isolated perfused heart and cardiomyocyte preparations. Intravenous injection of lysophosphatidic acid (2.8 to 14 microg/100 g body wt) increased the left ventricular systolic and diastolic pressures, rate of pressure development, and rate of pressure decay in rats. The positive inotropic effect of lysophosphatidic acid in vivo was not affected by the blockers of angiotensin II, endothelin-1, or adrenergic receptors, but this action was abolished by pretreatment with neurokinin type 1 receptor antagonist (L703606) as well as Ca2+-channel antagonist (verapamil). In the isolated heart, lysophosphatidic acid (1-10 microM) had no significant effect on cardiac function but higher concentrations (20-50 microM) elevated the left ventricular end diastolic pressure, significantly. Lysophosphatidic acid (1-30 microM) neither showed any effect on the basal intracellular concentration of free Ca2+ nor modified the KCl-induced increase in [Ca2+]i in freshly isolated cardiomyocytes. CONCLUSIONS: These results indicate that lysophosphatidic acid stimulated heart function under in vivo but not in vitro conditions. The positive inotropic effect of lysophosphatidic acid in vivo may be indirectly mediated by the activation of neurokinin type 1 receptors.
Adrenergic Agents↗
[Experimental study on allogeneic mandible transplantation combined with basic fibroblast growth factor]
OBJECTIVE: To study the effect of basic fibroblast growth factor(b-FGF) on revascularization and bone remodeling of allogeneic mandible transplantation in repair of mandible defects in rabbits. METHODS: The mandible defects of 20 adult rabbits were created in both sides. The defects on the left side were implanted with allogeneic bone and local administration of b-FGF; the defects on the right side were only repaired with allogeneic bone as control group. At 1, 3 months after operation, the revascularization and bone remodeling were observed by ink-gelation vascular perfusion-transparency and histological examination. RESULTS: The allogeneic bone and b-FGF group had more marked vascularization and more quick and complete bone formation than control group. CONCLUSION: b-FGF can improve revascularization and bone formation after allogeneic mandible transplantation; allogeneic bone combined with b-FGF is a promising bone substitute in clinical uses.
Journal Article↗
[Studies on biomechanics of human foot: a review].
The plantar pressure and shear force measurement, the function and effect of joints, bones and ligaments of foot during running and walking, and the modeling and finite element analysis of human foot are three important aspects in biomechanical study of foot. They are also the basis of the study of rehabilitation. In this paper, studies on the three aspects are reviewed, and further promising developments are proposed.
Biomechanical Phenomena↗
Tissue microarray analysis of maspin expression and its reverse correlation with mutant p53 in various tumors.
Maspin is a member of serpin family with tumor suppressing activity. Initially identified from normal mammary epithelial cells, maspin expression was down-regulated in breast tumor cells by both in vitro assay and by immunostaining of clinical specimen from breast cancer patients. Recently, maspin research has been advanced to clinical research aimed at correlating the tumor progression with the expression level of maspin in breast cancers. However, due to the variation and large sample sizes, no comparison study of maspin expression has been done using various normal and tumor samples. The tissue microarray is a technique recently developed for the standardization and high-throughput screening of clinical markers. We have used the tissue microarray to examine the maspin expression in various normal tissues and cancers. Our data indicated that maspin was expressed at different level in most of human tissues in the array. However, maspin expression was consistently down-regulated during tumor progression. There were no obvious correlation between maspin expression and tumor grades, nor was there any correlation with the age of patients. Since wild-type p53 was found to activate maspin promoter in vitro, we examined weather there was a connection between p53 level and maspin expression in vivo. Our data indicate that maspin expression inversely correlates with mutant p53 level in majority of cancer, suggesting maspin is likely a p53 target gene in vivo.
Adolescent↗
[Experimental methods for mechanically stimulating the cells in vitro].
Cellular mechanics is a branch of tissue engineering and cellular engineering. As one of the important method, loading different mechanical stimuli to culturing cells in vitro so as to study the influence that the stress has on the cells is one of the important fields of cellular mechanics. This paper reviews the experimental methods for mechanically stimulating the cells in vitro, according to the different loading modalities, the methods can be categorized into micropipette aspiration, compression loading, substrate distention, fluid shear, etc. And it also points out their advantages and disadvantages.
Cell Culture Techniques↗
Complications of percutaneous transluminal septal myocardial ablation in hypertrophic obstructive cardiomyopathy.
OBJECTIVE: To assess the complications of percutaneous tansluminal septal myocardial ablation (PTSMA) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Seventy-two patients with symptomatic left ventricular outflow tract obstruction were diagnosed by echocardiography or catheterization procedures. Absolute ethanol was injected into the target coronary artery branch (branches) for septal myocardial ablation. Documented complications were recorded. RESULTS: Sixty-nine patients had severe chest pain, 19 developed different degrees of heart block during the periprocedural period, but only one developed a complete AV block, requiring permanent pace-maker implantation. Temporary right bundle branch block occurred in 50% of patients and permanent block occurred in 38.9% of patients. Acute inferior myocardial infarction occurred in six patients (8.3%) and acute anterior myocardial infarction occurred in one patient. During two-year follow-up of 24 cases, there were no deaths. All patients had improvement in heart function and none experienced heart failure. CONCLUSION: The most common complication of PTSMA is right bundle branch block. The most significant complication of the procedure is heart block. PTSMA is a good technical, non-surgical treatment for HOCM.
Adolescent↗
[Fast automated finite element mesh generation of residual lower limb for clinical application].
Objective. To develop a model of fast automated mesh generation of residual lower limb for clinical application. Method. Actual geometry of the bone was represented as a standard pretreated model of bone, which was auto-located by employing an affine scaling transformation. Hexahedral or wedge elements were constructed by joining quadrilateral or triangular meshes generated by graph partitioning method and transport-mapping method from successive planar cross sections. Result. A model of fast automated mesh generation of residual lower limb was developed, which can be applied to different amputee and ensure the geometric integrality of bone. Auto-location of the bone was carried out. The mesh refinement can be controlled to adapt to different computational efficiency. The generated elements are hexahedral or wedge elements, both of which are more precise than tetrahedral element. Conclusion. The present method could be applied in finite element analysis method for prosthetic socket designing. Radioactive damage from those techniques such as CT or MRI to the amputee and the difficulty in image processing could be avoided.
Amputation Stumps↗
[Advances in research on pharmacogenomics].
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Animals↗
A new method for fast and accurate derivation of molecular conformations.
During molecular simulations, three-dimensional conformations of biomolecules are calculated from the values of their bond angles, bond lengths, and torsional angles. In this paper we study how to efficiently derive three-dimensional molecular conformations from the values of torsional angles. This case is of broad interest as torsional angles greatly affect molecular shape and are always taken into account during simulations. We first review two widely used methods for deriving molecular conformations, the simple rotations scheme and the Denavit-Hartenberg local frames method. We discuss their disadvantages which include extensive bookkeeping, accumulation of numerical errors, and redundancies in the local frames used. Then we introduce a new, fast, and accurate method called the atomgroup local frames method. This new method not only eliminates the disadvantages of earlier approaches but also provides lazy evaluation of atom positions and reduces the computational cost. Our method is especially useful in applications where many conformations are generated or updated such as in energy minimization and conformational search.
Journal Article↗
Selenium improves cardiac function by attenuating the activation of NF-kappaB due to ischemia-reperfusion injury.
Although selenium, an essential trace element and a component of glutathione peroxidase, is known to protect the heart from ischemia-reperfusion (I/R)-induced injury, the mechanisms of this protection are not fully understood. For this purpose, isolated rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion; sodium selenite (25-1,000 nM) was added in the perfusion medium 10 min prior to ischemia, as well as during reperfusion. Selenium caused a dose-dependent improvement in cardiac performance and attenuated the decrease in the ratio of reduced glutathione to oxidized glutathione, as well as the increased level of malondialdehyde in I/R heart. Elevated ratios of nuclear factor-kappaB (NF-kappaB) in particulate and cytosolic fraction and of phosphorylated NF-kappaB and total NF-kappaB in I/R hearts were reduced by selenium. Cardiac dysfunction in hearts perfused with xanthine plus xanthine oxidase mixture, as well as hydrogen peroxide, or subjected to Ca2+ paradox was also attenuated by selenium. These data suggest that selenium protects the heart against I/R injury due to its action on the redox state and deactivation of NF-kappaB in I/R hearts.
Animals↗
Effectiveness of insoles on plantar pressure redistribution.
For this study, we compared the effectiveness of different design insoles for redistributing pressure during walking for diabetic patients and for normal control subjects. Comparisons of dynamic plantar foot pressure patterns were made with different support, including shoe-only, flat insole, and three contoured insoles. We custom-molded the three contoured insoles by casting the plantar surface of the foot under the conditions of non-weight-bearing, semi-weight-bearing, and full-weight-bearing. With the F-Scan in-shoe system, the interfacial pressure distribution during walking with different plantar supports was measured at 50 Hz for 10 s. The use of insoles could significantly reduce local peak pressure and pressure-time integral and increase the contact area. Contoured insoles were significantly better than flat insoles with regard to the insole functions in reducing local peak pressures. The insole with the semi-weight-bearing foot shape can offer the greatest peak pressure reduction compared to other insole designs, especially for patients with peak pressure located at the second to third metatarsal heads.
Adult↗
Quantitative comparison of plantar foot shapes under different weight-bearing conditions.
Knowledge of the plantar foot shape alteration under weight bearing can offer implications for the design and construction of a comfortable and functional foot support. The purpose of this study was to quantify the change in three-dimensional foot shape under different weight-bearing conditions. The plantar foot shapes of 16 normal feet were collected by an impression casting method under three weight-bearing conditions: non-weight bearing, semi-weight bearing, and full-weight bearing. An optical digitizing system was used to capture the three-dimensional plantar surface shape of the foot cast. Measurements and comparisons from the digitized shapes were conducted for the whole foot and regions of the foot. The data showed that increased weight bearing significantly increased the contact area, foot length, foot width, and rearfoot width, while it decreased average height, arch height, and arch angle. Compared with the non-weight-bearing foot shape, the semi-weight-bearing condition would produce increases in the contact area of 35.1% +/- 21.6 %, foot length of 2.7% +/- 1.2%, foot width of 2.9% +/- 2.4%, and rearfoot width of 5.9% +/- 4.8%, and decreases in the arch height of 15.4% +/- 7.8% and arch angle of 21.7% +/- 17.2%. The full-weight-bearing condition would produce increases in the contact area of 60.4% +/- 33.2%, foot length of 3.4% +/- 1.3%, foot width of 6.0% +/- 2.1%, and rearfoot width of 8.7% +/- 4.9%, and decreases in the arch height of 20.0% +/- 9.2% and arch angle of 41.2% +/- 16.2%. The findings may be useful for considering the change of foot shape in the selection of shoe size and shoe or insole design.
Adult↗
Finite-element analysis to determine effect of monolimb flexibility on structural strength and interaction between residual limb and prosthetic socket.
Monolimb refers to a kind of transtibial prostheses having the socket and shank molded into one piece of thermoplastic material. One of its characteristics is that the shank is made of a material that can deform during walking, which can simulate ankle joint motion to some extent. Changes in shank geometry can alter the stress distribution within the monolimb and at the residual limb-socket interface and, respectively, affect the deformability and structural integrity of the prosthesis and comfort perceived by amputees. This paper describes the development of a finite-element model for the study of the structural behavior of monolimbs with different shank designs and the interaction between the limb and socket during walking. The von Mises stress distributions in monolimbs with different shank designs at different walking phases are reported. With the use of distortion energy theory, possible failure was predicted. The effect of the stiffness of the monolimb shanks on the stress distribution at the limb-socket interface was studied. The results show a trend--the peak stress applied to the limb was lowered as the shank stiffness decreased. This information is useful for future monolimb optimization.
Amputation, Surgical↗
Predicting tumor cell repopulation after response: mathematical modeling of cancer cell growth.
The kinetics of regrowth of tumor cells after treatment may offer a new end-point for clinical trials. Based on our testing, it is best described in this manner: y(t) = a*exp(-b*t) + c*exp(d*t). Human malignant glioma cells U87 MG were treated with etoposide and allowed to regrow after treatment. The cell number versus time data were fitted mathematically to the two-term exponential model. Parameters b and d were independent of the drug concentration, while a increased c decreased as the drug dose increased. The concentration independence of b and d indicated that both cell proliferation and cell death kinetics were independent of the drug treatment, which suggests constant times for cell cycle and apoptosis. The concentration dependence of c suggests that the time until the cells started regrowing depended on the treatment, repair mechanisms taking longer after heavy damage. The two-term exponential model predicted tumor repopulation in this in vitro system. These results indicated that the velocities of the logarithm of cell growth and cell death were independent of drug treatment, while the recovery time of the tumor repopulation was dependent on the drug dose. The two-term exponential model can be used to predict tumor repopulation in an in vitro system and this model will be further tested using clinical data.
Cell Growth Processes↗