Interactions of neural-like cells with 3D-printed polycaprolactone with different inner diameters for neural regeneration

Background/purpose

Peripheral neural regeneration is an interesting and challenging field. The aim of this study was to investigate the interactions of neural-like PC12 cells and Poly-D-Lysine (PDL)-coated 3D-printed polycaprolactone (PCL) scaffolds with different inner diameters of half tubular array (HTA) (0, 200, 300, and 400 μm), respectively.

Materials and methods

This study used the fused deposition modeling (FDM) technique with 3D-printing to fabricate the thermoplastic polymer. Scaffold properties were measured by mechanical testing, and coating quality was observed under a scanning electron microscope (SEM). PC12 cell biocompatibility was examined by an MTT assay. Cell differentiation was evaluated by immunofluorescence staining.

Results

The cell viability of PC12 cells on PDL-coated PCL scaffolds with a 200-μm inner diameter of HTA was shown with significant differences (∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001) than other PCL groups at all experimental dates. The SEM observation showed that PDL-coated PCL scaffolds with 200-μm inner diameters of HTA promoted cell adhesion. An immunofluorescence staining of PC12 cells on the PDL-coated PCL scaffold with a 200-μm inner diameter of the HTA group showed that it stimulated PC12 cells for neurite formation much better than the other groups.A PDL-coated PCL scaffold with a 200-μm inner diameter of HTA can promote the growth and differentiation of PC12 cells better than other groups. It indicated that PDL-coated PCL scaffolds with a 200-μm inner diameter HTA can be used for further neural regeneration application.

3D-printed polycaprolactone scaffolds coated with beta tricalcium phosphate for bone regeneration

BACKGROUND/PURPOSE

3D-printing technology is an important tool for the bone tissue engineering (BTE). The aim of this study was to investigate the interaction of polycaprolactone (PCL) scaffolds and modified mesh PCL coated with beta TCP (PCL/β-TCP) scaffolds with MG-63.

METHODS

This study used the fused deposition modeling (FDM) technique with the 3D printing technique to fabricate the thermoplastic polymer and composite scaffolds. Scaffold structure and coating quality were observed under a scanning electron microscope (SEM). MG-63 cells were injected and attached to the mesh-manufactured PCL scaffolds. The biocompatibility of mesh structured PCL and PCL/β-TCP scaffolds could be examined by measuring the viability of MG-63 cells of MTT assay. Bone cell differentiation was evaluated ALP activity by mineralization assay.

RESULTS

The results showed that both mesh PCL scaffolds and PCL/β-TCP scaffolds were non-toxic to the cells. The ALP activities of cells in PCL/β-TCP scaffolds groups were significant differences and better than PCL groups in all groups at all experimental dates. The mineralization process was time-dependent, and significantly higher mineralization of osteosarcoma cells was observed on PCL/β-TCP scaffolds at experimental dates.

CONCLUSION

We concluded that both meshes structured PCL and PCL/β-TCP scaffolds could promote the MG-63 cell growth, and PCL/β-TCP was better than the PCL scaffolds for the outcome of MG63 cell differentiation and mineralization.

The influence on surface characteristic and biocompatibility of nano-SnO2-modified titanium implant material using atomic layer deposition technique

BACKGROUND/PURPOSE

To investigate the surface characteristics of titanium (Ti) implant materials, which were coated with different thicknesses of nanoscale tin oxide (SnO₂) using the atomic layer deposition technique, and evaluated its biological performance on human embryonic palatal mesenchyme (HEPM) cells.

METHODS

The thickness of the coating layer on Ti was 0 (Ti0), 20 nm (Ti20), 50 nm (Ti50), and 100 nm (Ti100), respectively. The surface morphology was observed with an SEM and AFM. The root mean square roughness of micron-scale (mRq) and nanoroughness (nRq) of Ti discs' surface were measured. The Alamar blue (AB) assay and F-actin fluorescence staining were used to evaluate the biocompatibility, and the osteocalcin (OCN) was measured to clarify the differentiation of HEPM cells on materials.

RESULTS

In the coating groups, the mRq was decreased, but the nRq was increased. The spreading and polygonal morphology of HEPMs was apparent in coating groups. On Day 4, the survival rate of HEPM cells on Ti0 was higher than on Ti20 and Ti50. There was no significant difference on Day 7, Day 10, and Day 14. The OCN was significantly higher on Day 14 in all the coating groups than Ti0.

CONCLUSION

The results showed that the cell growth was intensified with rough surfaces. However, the OCN and morphology change was prominent when the nanoroughness was increased, which meant the increased nanoroughness might enhance OCN production and improve the tendency of osseointegration. The nanoscale SnO₂ coating could increase the ability of bone formation but not cell growth.

From folk therapy to evidence-based psychiatry practice: The benefit of evidence-based psychiatry in treatment-naive psychotic patients

BACKGROUND

As Taiwan's Mental Health Act (MHA) clearly states that the human rights and legal rights of psychotic patients should be respected and guaranteed; however, a temple asylum violates the law in the 21st century. Hundreds of patients were constrained in the asylum for years without consent. Because of outbreak of infectious diseases, patients were evacuated from the asylum by the official intervention.

AIMS

To evaluate the outcomes of these patients from folk therapy to conventional treatment.

METHOD

The study recruited the drug-naive psychotic patients constrained in an asylum for decades. Before and after the formal treatment, 253 patients were diagnosed with schizophrenia and other psychotic disorders with assessment of using the Mini Positive and Negative Syndrome Scale (Mini-PANSS) and Comprehensive Occupational Therapy Evaluation (COTE) scale. In addition, family function, self-care ability and nutritional status were also evaluated.

RESULTS

The initial data show the improvement in psychotic symptoms and occupational function in these patients. Furthermore, the ratio of patients who were classified as being at risk for malnutrition was decreased by 21.7% after treatment. There was no statistically significant difference in self-care ability before and after treatment.

CONCLUSION

The psychotic symptoms and occupational function of these patients were improved after the formal treatment compared to the folk therapy. The care model for the psychotic patients in the temple asylum should be more thoroughly discussed in consideration of the medical ethics principles.

Bioanalytical system for detection of cancer cells with photoluminescent ZnO nanorods

Using photoluminescent ZnO nanorods and carbohydrate marker SSEA-4, a novel cancer cell recognition system was developed. Immobilization of SSEA-4 antibodies (αSSEA-4) on ZnO nanorods was performed in buffer solution (pH = 7.1) over 2 h. The cancer cell line probes were fixed on the glass slide. One hundred microliters of ZnO-αSSEA-4 conjugates were deposited on the cell probe and exposed for 30 min. After washing photoluminescence spectra were recorded. Based on the developed methodology, ZnO-αSSEA-4 probes were tested on patient-derived breast and colorectal carcinoma cells. Our data clearly show that the carbohydrate SSEA-4 molecule is expressed on cancer cell lines and patient-derived cancer cells. Moreover, SSEA-4 targeted ZnO nanorods bind to the patient-derived cancer cells with high selectivity and the photoluminescence signal increased tremendously compared to the signal from the control samples. Furthermore, the photoluminescence intensity increase correlated with the extent of malignancy in the target cell population. A novel portable bioanalytical system, based on optical ZnO nanorods and fiber optic detection system was developed. We propose that carbohydrate SSEA-4 specific ZnO nanorods could be used for the development of cancer diagnostic biosensors and for targeted therapy.

Inhibition of growth and migration of oral and cervical cancer cells by citrus polyphenol

BACKGROUND/PURPOSE

It has been confirmed that polyphenolic compounds present in food have various pharmaceutical functions. The purpose of this study was to evaluate citrus polyphenol (CP) for dental applications. The culture medium with CP was developed to inhibit the proliferation of oral cancer cells. CP could be used as a supplemental compound for topical application for oral cancer patients.

METHODS

In this study, the metabolic activity and cell toxicity of CP (at concentrations of 1%, 0.1%, and 0.01%) for oral and cervical cancer cells were investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays (n = 6). Furthermore, the effects of CP on motilities of oral and cervical cancer cells were also evaluated using a scratch assay model.

RESULTS

We found that the growth of Ca9-22 and HeLa cells on tissue culture polystyrene was greatly inhibited when 1% CP was added to the medium. In addition, significant differences (p < 0.01) in cytotoxicities of oral and cervical cancer cells were observed after 6 days in the culture medium to which 1% CP was added. Furthermore, using a scratch assay model to evaluate the migratory abilities of oral and cervical cancer cells, it was also found that CP could inhibit the migratory abilities of cancer cells.

CONCLUSION

The results confirmed the feasibility of the topical application of CP as a supplemental compound for inhibition of cancer cell proliferation and migration.

A novel polyurethane/cellulose fibrous scaffold for cardiac tissue engineering

A high mechanical strength and biomimetic scaffold is electrospun from a blend of polyurethane and ethyl cellulose, being promising in applications for therapeutic purposes as a cardiac graft for reconstructing or regeneration of damaged myocardium.

Low pressure radio-frequency oxygen plasma induced oxidation of titanium--surface characteristics and biological effects

OBJECTIVE

This research was designed to investigate the effects of low pressure radio-frequency (RF) oxygen plasma treatment (OPT) on the surface of commercially pure titanium (CP-Ti) and Ti6Al4V. Surface topography, elemental composition, water contact angle, cell viability, and cell morphology were surveyed to evaluate the biocompatibility of titanium samples with different lengths of OP treating time.

MATERIALS AND METHODS

CP-Ti and Ti6Al4V discs were both classified into 4 groups: untreated, treated with OP generated by using oxygen (99.98%) for 5, 10, and 30 min, respectively. After OPT on CP-Ti and Ti6Al4V samples, scanning probe microscopy, X-ray photoelectron spectrometry (XPS), and contact angle tests were conducted to determine the surface topography, elemental composition and hydrophilicity, respectively. The change of surface morphology was further studied using sputtered titanium on silicon wafers. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and F-actin immunofluorescence stain were performed to investigate the viability and spreading behavior of cultivated MG-63 cells on the samples.

RESULTS

The surface roughness was most prominent after 5 min OPT in both CP-Ti and Ti6Al4V, and the surface morphology of sputtered Ti sharpened after the 5 min treatment. From the XPS results, the intensity of Ti(°), Ti(2+), and Ti(3+) of the samples' surface decreased indicating the oxidation of titanium after OPT. The water contact angles of both CP-Ti and Ti6Al4V were increased after 5 min OPT. The results of MTT assay demonstrated MG-63 cells proliferated best on the 5 min OP treated titanium sample. The F-actin immunofluorescence stain revealed the cultivated cell number of 5 min treated CP-Ti/Ti6Al4V was greater than other groups and most of the cultivated cells were spindle-shaped.

CONCLUSIONS

Low pressure RF oxygen plasma modified both the composition and the morphology of titanium samples' surface. The CP-Ti/Ti6Al4V treated with 5 min OPT displayed the roughest surface, sharpest surface profile and best biocompatibility.

Omniphobic low moisture permeation transparent polyacrylate/silica nanocomposite

We report the development of low moisture permeation and transparent dense polyacrylate/silica nanocomposite material that can exhibit both superhydrophobic and oleophobic (omniphobic) properties. The material was prepared by a three-step process. The first step involved the preparation of UV polymerizable solventless hybrid resin and the fabrication of nanocomposite. The hybrid resin consisted of a mixture of acrylate monomer, initiator, and acrylate-modified different size silica nanoparticles. The second step was to roughen the surface of the nanocomposite with unique nanotexture by oxygen plasma. In the third step, we applied a low surface tension fluoro monolayer on the treated surface. The nanocomposite exhibits desired superhydrophobicity and oleophobicity with a water contact angle of 158.2° and n-1-octadecene contact angle of 128.5°, respectively; low moisture permeation of 1.44 g·mm/m(2)·day; and good transparency (greater than 82% at 450-800 nm for ~60 μm film). The material has potential applications in optoelectronic encapsulation, self-cleaning coating, etc.

Molecular structure effect of pyridine-based surface ligand on the performance of P3HT:TiO₂ hybrid solar cell

Colloid TiO(2) nanorods are used for solution-processable poly(3-hexyl thiophene): TiO(2) hybrid solar cell. The nanorods were covered by insulating ligand of oleic acid (OA) after sol-gel synthesis. Three more conducting pyridine type ligands: pyridine, 2,6-lutidine (Lut) and 4-tert-butylpyridine (tBP) were investigated respectively to replace OA. The power conversion efficiency (PCE) of the solar cell was increased because the electronic mobility of pyridine-type ligand-modified TiO(2) is higher than that of TiO(2)-OA. The enhancement of PCE is in the descending order of Lut > pyridine > tBP because of the effective replacement of OA by Lut. The PCE of solar cell can be further enhanced by ligand exchange of pyridine type ligand with conjugating molecule of 2-cyano-3-(5-(7-(thiophen-2-yl)-benzothiadiazol-4-yl) thiophen-2-yl) acrylic acid (W4) on TiO(2) nanorods because W4 has aligned bandgap with P3HT and TiO(2) to facilitate charge separation and transport. The electronic mobility of two-stage ligand exchanged TiO(2) is improved furthermore except Lut, because it adheres well and difficult to be replaced by W4. The amount of W4 on TiO(2)-tBP is 3 times more than that of TiO(2)-Lut (0.20 mol % vs. 0.06 mol %). Thus, the increased extent of PCE of solar cell is in the decreasing order of tBP > pyridine > Lut. The TiO(2)-tBP-W4 device has the best performance with 1.4 and 2.6 times more than TiO(2)-pyridine-W4 and TiO(2)-Lut-W4 devices, respectively. The pKa of the pyridine derivatives plays the major role to determine the ease of ligand exchange on TiO(2) which is the key factor mandating the PCE of P3HT:TiO(2) hybrid solar cell. The results of this study provide new insights of the significance of acid-base reaction on the TiO(2) surface for TiO(2)-based solar cells. The obtained knowledge can be extended to other hybrid solar cell systems.

Auditory efferent dysfunction in normal-hearing chronic idiopathic tinnitus

OBJECTIVE

To investigate the function of the auditory efferent system in patients with chronic idiopathic tinnitus, but normal pure-tone audiograms.

METHODS

We studied 15 subjects with normal hearing that had experienced either unilateral or bilateral persistent tinnitus for at least 3 months. The ears of the 15 subjects were classified into tinnitus-positive-ear (TPE) and tinnitus-negative-ear (TNE) groups. The control-ear group (CE) comprised the ears of 15 subjects with normal hearing and no tinnitus. We measured different types of otoacoustic emissions (OAEs), including spontaneous (SOAEs), transient evoked (TEOAEs), and distortion product (DPOAEs). We also analyzed contralateral suppression of OAEs and auditory brainstem responses (ABRs). Data were compared among TPE, TNE, and CE groups.

RESULTS

The data associated with cochlear mechanics, including the prevalence of SOAEs, the number of SOAE peaks, and the overall TEOAE responses in the absence of a contralateral stimulus, were not significantly different among the TPE, TNE, and CE groups. In the TPE group, contralateral stimuli failed to significantly suppress overall TEOAEs, and contralateral suppression of DPOAEs was significantly reduced over a limited frequency range. Furthermore, the TPE group showed prolonged latencies in waves III and V of ABRs.

CONCLUSION

This study demonstrated that abnormal contralateral suppression of OAEs and ABRs indicated a dysfunction in the ipsilateral efferent medial olivocochlear system; this might play a role in normal-hearing tinnitus.

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (∼70-100 nm). The nanoparticles were modified by an epoxy silane of γ-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (∼42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ∼50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility, comparable to commercialized composites. The results indicate that this novel LC nanocomposite is worthy of development and has potential for further applications in clinical dentistry.

Broadband and omnidirectional antireflection employing disordered GaN nanopillars

Disordered GaN nanopillars of three different heights: 300, 550, and 720 nm are fabricated, and demonstrate broad angular and spectral antireflective characteristics, up to an incident angle of 60? and for the wavelength range of lambda=300-1800 nm. An algorithm based on a rigorous coupled-wave analysis (RCWA) method is developed to investigate the correlations between the reflective characteristics and the structural properties of the nanopillars. The broadband and omnidirectional antireflection arises mainly from the refractive-index gradient provided by nanopillars. Calculations show excellent agreement with the measured reflectivities for both s- and p- polarizations.

Raloxifene versus continuous combined estrogen/progestin therapy: densitometric and biochemical effects in healthy postmenopausal Taiwanese women

We treated 116 healthy postmenopausal women (age 47-66 years, mean 57 years) in Taiwan with either raloxifene (RLX) 60 mg (n = 92) or 0.625 mg conjugated equine estrogen plus 5 mg medroxyprogesterone acetate (CCEP, n = 24) daily for 12 months in a randomized, double-masked, active-controlled fashion. The results showed that both regimens increased bone mineral density (BMD) at hip sites (means: RLX 2.5-4.9%, CCEP 4.6-7.9%, all p<0.005 compared with baseline), and the difference between the two regimens was not significant. The spinal BMD increased significantly in both groups (1.4% with RLX and 6.0% with CCEP, both p<0.01), and more with CCEP (p<0.003). Osteocalcin levels and urinary type I collagen C-telopeptide/creatinine ratios decreased significantly in both regimens, but the decreases were significantly larger with CCEP. Compared with baseline, both RLX and CCEP decreased the total cholesterol (median 4.9% and 8.6% respectively, p<0.001) and LDL-cholesterol (median 11% and 19% respectively, p<0.001), and increased HDL-cholesterol (median 8.6% and 10.7% respectively, p<0.01). Both regimens increased triglyceride levels (median 3.2% and 18.9% respectively, both p<0.05), although to a lesser extent with RLX than with CCEP (p<0.05). Only 3 subjects (3.3%) reported vaginal bleeding in the RLX group, as compared with 31% (7/22) with CCEP (p<0.05). We conclude that in healthy, postmenopausal Taiwanese women, RLX 60 mg given daily has favorable results in BMD, bone turnover and serum lipids, although the dosage we used showed a potency less than that of conventional CCEP.

A novel member of the RBCC family, Trif, expressed specifically in the spermatids of mouse testis

Members of the RING finger family are implicated in a variety of functions such as signal transduction, transcriptional regulation and other developmental processes. Using degenerate oligonucleotide primers corresponding to the RING domain, we isolated a novel RING finger gene from the mouse testis cDNA library, which was about 1.8 kb and was termed Trif (testis-specific ring finger). This deduced protein contains an N-terminal RING-finger, a B-box, and a C-terminal B-30.2-like domain, which make the Trif protein a member of the RING finger-B-box-coil-coil family. Northern blot analysis of adult multiple tissues indicated that Trif is expressed predominantly in the testis. Further analysis detected Trif transcripts in the testis from day 20 of the postnatal stage. In situ hybridization indicated that Trif is expressed in the round spermatids of the seminiferous tubules. These expression data suggest that Trif may play an important role in the regulation of spermatogenesis.

Spz1, a novel bHLH-Zip protein, is specifically expressed in testis

We isolated a novel bHLH-Zip gene designated Spz1 from a mouse testis cDNA library. Spz1 is expressed specifically in the testis and epididymis. Immunofluorescence staining detected Spz1 protein in the nuclei of LFG6 Leydig cells. The ability of Spz1 protein to bind to the bHLH consensus-binding site, the E-box, was confirmed by EMSA, and a 9-bp asymmetric target site was identified by random selection and PCR amplification. Hormonal regulation of Spz1 was investigated and downregulation of Spz1 expression by testosterone and retinoic acid was found. This nuclear transcription factor may play a crucial role in spermatogenesis by regulating cell proliferation or differentiation through binding to specific DNA sequences like other bHLH-Zip molecules.

Anticancer activity evaluation of the solanum glycoalkaloid solamargine. Triggering apoptosis in human hepatoma cells

Solamargine, an herbal and molluscicidal medicine derived from Solanum incanum, is a steroidal alkaloid glycoside. To characterize the anticancer mechanism of solamargine on human hepatoma cells (Hep3B), changes of cell morphology, DNA content, and gene expression of cells after solamargine treatment were studied. The appearance in solamargine-treated cells of chromatin condensation, DNA fragmentation, and a sub-G(1) peak in a DNA histogram suggests that solamargine induces cell death by apoptosis. The maximum number of dead Hep3B cells was detected within 2 hr of incubation with constant concentrations of solamargine, and no further cell death was observed after an extended incubation with solamargine, indicating that the action of solamargine was irreversible. To determine the susceptibility of cell phases to solamargine-mediated apoptosis, Hep3B cells were synchronized at defined cell cycles by cyclosporin A, colchicine, and genistein, followed by solamargine treatment. The IC(50) values of solamargine for control, G(0)/G(1)-, M-, and G(2)/M-synchronized Hep3B cells were 5.0, > 10, 3.7, and 3.1 microg/mL, implying that cells in the G(2)/M phases are relatively susceptible to solamargine-mediated apoptosis. In addition, a parallel up-regulation of tumor necrosis factor receptor (TNFR)-I and -II on Hep3B cells was detected after solamargine treatment, and the solamargine-mediated cytotoxicity could be neutralized with either TNFR-I or -II specific antibody. Therefore, these results reveal that the actions of TNFR-I and -II on Hep3B cells may be independent, and both are involved in the mechanism of solamargine-mediated apoptosis.

Effects of alendronate on osteopenic postmenopausal Chinese women

To evaluate the effects of alendronate on postmenopausal Chinese women with osteopenia, we treated 46 subjects daily with either 10 mg alendronate (N = 24) or placebo plus 500 mg calcium supplement (N = 22), and measured their bone mineral density (BMD) at the lumbar spine and hip, and urinary bone resorption markers before, during, and after the 1 year treatment period. The bone markers included N-telopeptide of type I collagen (NTx) and deoxypyridinoline (Dpd); both were corrected by the concentration of creatinine in the same sample (NTx/Cr and Dpd/Cr). Both NTx/Cr and Dpd/Cr decreased significantly by 44% and 28%, respectively (p < 0.05 for both), in 1 month in the active treatment group but did not change in the placebo group. BMD at the spine, femoral neck, trochanter, and Ward's triangle increased significantly by 6 months and showed a further increase through month 12 at the spine in the alendronate-treated group. Relative to the placebo group, BMD changes at various sites in the alendronate-treated group were higher at 12 months by 6%-11%. Thus, our data suggest that 10 mg alendronate daily resulted in significant increases in spine and hip BMD, and decreases of urinary resorption markers in the osteopenic postmenopausal Chinese women studied. The amplitude of responses was higher than in previous reports in the USA and Europe.

Interword spacing in Chinese text layout

Three experiments using Chinese text were conducted to investigate word spacing and its effect on reading performance. In Exp. 1, a sonogram detector was used to analyze interword and intercharacter (within a word) time intervals from text read aloud by professional TV broadcasters versus college graduates. The results showed interword intervals were significantly longer than intercharacter intervals, indicating that interword spacing has psychological reality in speech. Exp. 2 examined the effect on reading performance due to separating the characters that compose a word. Separating the characters of a word did not decrease reading accuracy but did result in significantly longer reading times. Exp. 3 explored the effect of word spacing in Chinese sentences on reading performance. Analysis showed that word spacing did not affect reading accuracy, but half character and whole-character spacing significantly reduced reading time. The results of the present study suggest that word spacing in Chinese text layout enhances reading performance. Word spacing may help the reader to segment more quickly a string of characters into words and reduce the likelihood of misinterpretation. Also, ambiguity of sentence structure severely degraded reading accuracy. The implications of the results for word spacing design in Chinese text are discussed.

The hepatoprotective effects of Solanum alatum Moench. on acetaminophen-induced hepatotoxicity in mice

Solanum alatum Moench. has been shown to have a protective effect against carbon tetrachloride (CCl4)-induced liver injury. Solanum alatum treatment (100 mg/kg, p.o.) decreased the elevation of serum alanine aminotransferase (ALT; GPT) and aspartate aminotransferase (AST; GOT) induced by acetaminophen (paracetamol) (600 mg/kg, i.p.) administration. It also decreased the extent of visible necrosis in liver tissue. In addition, Solanum alatum treatment restored hepatic glutathione (GSH) depletion induced by acetaminophen (600 mg/kg, i.p.) administration. Microsomal enzyme levels such as P-450, reductase, and aniline hydroxylation enzyme were also restored to normal levels after Solanum alatum administration. The hepatoprotective mechanism may function through direct binding with acetaminophen toxic metabolites, decreasing the attraction of acetaminophen metabolites for other cellular GSH or thiol protein. Additionally, Solanum alatum treatment increased the concentration of hepatic GSH and maintained a high level activity of GSTase, which led to acceleration of the excretion of toxic acetaminophen metabolites.

Hemangiopericytoma of the pleura causing massive hemothorax

Hemangiopericytoma is an unusual soft tissue tumor. A 54-year-old man presented with sudden onset of chest pain and dyspnea for 1 day. The initial chest x-ray showed a massive left pleural effusion. A contrast-enhanced computed tomographic scan of the chest showed a homogenously enhanced mass in the intrathoracic extrapulmonary space. A tube thoracostomy was performed and hemothorax was confirmed. A posterolateral thoracotomy was performed and a tumor in the parietal pleura of the left chest wall was resected. Grossly, the resected tumor arose from the parietal pleura, and the cut surface was elastic, soft, and pale yellow. There were several cystic formations and hemorrhages. Based on histologic findings, hemangiopericytoma with lower grade malignancy was diagnosed. The patient was alive and free from tumor recurrence 1 year after surgery. Intrathoracic extrapulmonary hemangiopericytoma is extremely rare, and surgical excision is the treatment of choice. Adjuvant chemotherapy or radiotherapy is indicated because of the high risk of recurrence and potential malignancy.

Effects of word spacing on reading Chinese text from a video display terminal

This study investigated the effects of designing space between words in Chinese text, i.e., whether using a "word" instead of a "character" as a presentation unit, will facilitate the performance of reading from a video display terminal. Experimental results indicated that the main effect of word spacing significantly affected the reading time and the number of questions answered correctly. Subjects spent less time on the text with half-character word spacing or with whole-character word spacing than with conventional type (without word spacing). We also discovered that the number of questions answered correctly for stimuli with half-character spacing is significantly greater than that for stimuli with whole-character spacing, while both are smaller than for stimuli with conventional type. The additional variables, such as text difficulty and display control have significant effects as well. Our results suggested that the optimal word spacing in Chinese text should be greater than that in the traditional layout and less than a whole-character spacing. Apparently, in Chinese text, using a "word" as a presentation unit is more favorable than the traditional layouts that do not have any explicit word boundaries. The word spacing design may benefit in reading difficult or unfamiliar materials and further apply in emergency situations or in reading ambiguous sentences.

Improved cell adhesion by plasma-induced grafting of L-lactide onto polyurethane surface

Lactide-grafted polyurethanes were prepared by exposing the polyurethane films to argon plasma discharge, followed by grafting L-lactide onto the plasma-treated surface. The modified surfaces were characterized by measuring the static contact angle and by electron spectroscopy for chemical analysis (ESCA). The water contact angle of polyurethanes was decreased by L-lactide grafting, indicating hydrophilicity of the modified surface. Grafting also increased the O/C atomic ratio and C(C=O)/Ctotal percentage on the surfaces as detected by ESCA. The grafted surfaces showed enhanced attachment and growth in both 3T3 fibroblast and human umbilical vein endothelial cell culture tests. Platelet adhesion to the modified surfaces was also reduced in vitro. L-Lactide monomers grafted onto polyurethane substrates could therefore be useful in facilitating endothelial cell seeding process in small vascular graft applications.

Polyurethane blended with polylactides for improved cell adhesion and reduced platelet activation

Poly(L-lactide) (PLLA) or 50:50 poly(lactide-co-glycolide) (PLGA) was blended with a commercial polyurethane (PU), Pellethane 2103-80A, using a mutual solvent technique. After preparation by salt casting, the mechanical properties of the porous matrices were measured, and the surface element was characterized by electron spectroscopy for chemical analysis. The attachment and growth of fibroblasts as well as human umbilical vein endothelial cells on the substrates were investigated by the cell culture test. Platelet activation on different substrates was also studied. It was found that blending with these biodegradable polymers, especially PLGA. enhanced the cellular attachment and growth. This enhancement may be correlated with the higher oxygen/carbon (0/C) atomic ratio on the surface of the blends. Blending with either PLLA or PLGA was also found to decrease platelet adhesion and activation in vitro. These characteristics make PU/polylactide blends potential substrates for cardiovascular applications.

The influence of propolis ethanol extract on liver microsomal enzymes and glutathione after chronic alcohol administration

Propolis designates a series of gums, resins and balms of viscous consistency, which are gathered by honeybees from certain parts, mainly the buds and barks of plants, especially those found on coniferous trees. Bees bring propolis back to the hive, where it is modified and mixed with other substances including the bees' own wax and salivary secretions. In this study, the influences of propolis ethanol extract on chronic alcohol induced liver microsomal enzyme changes were investigated. Three grams of alcohol was added to rats' daily diet for four weeks to induce chronic alcohol liver injuries, and two different doses of propolis ethanol extract were p.o. administrated three times per day on the 28th, 29th, and 30th day. During the period of propolis administration, the ethanol diet was continued. After sacrifice, the rat livers were excised for assay of microsomal enzymes activity, glutathione (GSH) concentration, glutathione-S-transferase (GSTase) and gamma-glutamylcysteine synthetase (gamma-GCSase) activity. It was found that 30 mg/kg of propolis ethanol extract significantly prevented the elevations of total cytochrome P-450 enzymes, NADPH-dependent cytochrome C reductase, aniline hydroxylation, 7-ethoxyresorufin hydroxylation (7-ERH), 7-penthoxyresorufin hydroxylation (7-PRH), and lipid peroxidation induced by chronic ethanol administration. Additionally, propolis ethanol extract (100 mg/kg) also induced GSTase and gamma-GCSase activities and decreased glutathione levels in the liver.

The effectiveness of cyclic and continuous oral clodronate therapy on bone density and markers in osteopenic postmenopausal women

Bisphosphonates have been used effectively to treat established osteoporosis and prevent postmenopausal bone loss. However, the optimal manner of its administration-whether cyclic or continuous-has not been well established. This study investigated the efficacy of cyclic and continuous oral administration of clodronate in 54 newly identified osteopenic postmenopausal women in a randomized, double-blind, crossover fashion. The participants were randomly separated into two groups. The cyclic group (n = 29) received 800 mg twice daily of oral clodronate for 2 weeks every 3 months for the first 12 months followed by placebo for the second 12 months. The continuous group (n = 25) received placebo in the first 12 months and ingested 400 mg of clodronate once daily for the second 12 months. The urinary amino-terminal (NTXtrade mark) and carboxy-terminal (CrossLapstrade mark) cross-linked fragments of type I collagen, both markers of bone resorption, showed a marked decrease (25-50%) with both regimens during the period of active treatment. In the cyclic group, the levels of these two markers increased in the second 12 months with placebo, but did not return to the baseline completely. However, bone mineral density (BMD), determined by dual-energy X-ray absorptiometry (DXA), showed no significant change of BMD at various sites after 1 year of active treatment in both groups. Thoracic and lumbar spine X-ray showed no new vertebral fracture in either group after 2 years of treatment. With the two treatment protocols in this study, oral clodronate was effective in decreasing postmenopausal bone resorption, causing no significant changes in BMD at various sites.

The effect of epitope variation on the profile of cytotoxic T lymphocyte responses to the HIV envelope glycoprotein

To address the relationship between viral and host factors during HIV infection, we analyzed the effect of viral mutations on T cell responses in seropositive, asymptomatic HLA-A2+ individuals using four envelope (env)-specific peptides with the HLA-A*0201 binding motif. We showed that the natural sequence variation was frequent within epitopes located in the C-terminal region of the env glycoprotein and was largely responsible for a lower env-specific cytotoxic T lymphocyte (CTL) activity in the peptide-stimulated cultures. The highest CTL responses in vitro were induced with conserved epitopes D1 and 4.3 that mapped to the N-terminal region of the env glycoprotein. These peptides exhibited high binding affinity for HLA-A*0201 molecules and stimulated CD8+ T cells of relatively limited TCR Vbeta chain repertoire. Decreased CTL activities to the D1 epitope were observed in the absence of any detectable viral mutation, and were associated with lower proliferative responses and expression of the CD28 antigen. Results of this study demonstrate that the degree of sequence variation within a stimulatory epitope of the viral quasispecies, as well as proliferative potential of the effector cells, are among the factors underlying decreased CTL activity in HIV-infected patients. These experiments also provide evidence that the D1 peptide might be useful for the development of vaccines and immune-based therapy.

Air-liquid interfacial movement in models simulating airway reopening

In this model study, we simulated the initial airway reopening event in a rigid tube model. The air-liquid interface during airway reopening was assumed to be a simple axisymmetric meniscus similar to that of a two-phase flow in a rigid tube (radius R), where the applied pressures and the meniscus velocities were measured experimentally for fluids of different viscosities and surface tensions (gamma). Bulk flow contribution was deducted from the applied pressure to obtain the pressure accounting for interfacial movement (P*(int)). A semi-empirical formula for the interface was generated by dimensional analysis. The dimensionless interfacial pressure (P(int) = P*(int),R/gamma) was found to approach 2 for sufficiently small velocities, consistent with Bretherton's theoretical prediction. This formula also resembles that previously obtained in collapsible tubes simulating airways. The result suggests that the critical pressures required to reopen a collapsible airway and a non-collapsible one with the same radius are similar in magnitude (approximately 2 - 3gamma/R). However, in a collapsible airway, no significant bulk flow of lining fluids would develop while the interface proceeds, leading to a much smaller overall pressure for further reopening. Airway wall collapsibility thus could play a crucial role in maintaining proper ventilation through rapid reopening of the airway.

The effect of deletion of the V3 loop of gp120 on cytotoxic T cell responses and HIV gp120-mediated pathogenesis

New strategies for improving the efficacy of HIV vaccines are of significant importance. In this study, we analyzed the effect of deletion of the hypervariable V3 loop of gp120 on envelope (env)-specific CTL responses in PBMC of HIV-infected individuals. We showed increased CTL activities against conserved epitopes of the env glycoprotein in cultures induced with the AV3 mutant compared with those stimulated with the full-length env gene products. In contrast to the wild-type env, the AV3 mutant-expressing cells were resistant to Ab-dependent cell-mediated cytotoxicity, formed no syncytia, and neither underwent nor induced apoptosis in CD4+ cells. Thus, the AV3 mutant may redirect immune responses toward conserved epitopes of gp160, has longer expression time due to increased resistance to Ab-dependent cell-mediated cytotoxicity, and does not trigger cytopathic effects associated with apoptosis and syncytium formation. This approach may apply to other Ags of HIV, where deletions of highly variable or immunosuppressive epitopes may improve the efficacy of HIV vaccines.

Mediation of the cytotoxicity of lanostanoids and steroids of Ganoderma tsugae through apoptosis and cell cycle

A new lanostanoid ester glucoside, 3 alpha-acetoxy-5 alpha-lanosta-8,24-dien-21-oic acid ester beta-d-glucoside (1), and a known steroid, 2 beta,3 alpha,9 alpha-trihydroxy-5 alpha-ergosta-7,22-diene (2), were isolated from the fruit bodies of Ganoderma tsugae and their structures determined by spectroscopic methods. To study the cytotoxicity of 1 and 2, the changes of DNA content in human hepatocytes (Hep 3B) were studied. A sub-G1 cell stage was drastically increased after 24-h incubation with 1 (24 micrograms/mL). Compound 2 (100 micrograms/mL) inhibited the cell cycle progression of Hep 3B cells at the G2/M phase with an IC50 value of about 87.1 micrograms/mL. These results indicate that 1 causes cell death by apoptosis and 2 may possess the activity of cell cycle inhibition.

The hepatoprotective and therapeutic effects of propolis ethanol extract on chronic alcohol-induced liver injuries

Propolis designates a mixture of gums, resins and balms, of viscous consistency, which are gathered on certain parts (buds and bark, mainly) of vegetables (especially coniferous trees) by honeybees. They bring this back to the hive, where it is modified and mixed with other substances (essentially their own wax and salivary secretions). In this study, the hepatoprotective and therapeutic effects of propolis ethanol extract on chronic alcohol-induced liver injuries were investigated in rats. 3.125 ml of 99.5% alcohol was added to animal's daily diet for four weeks to induce chronic alcohol liver injuries. After sacrifice, serum transaminases (GOT, GPT), triacylglyceride and hepatic triacylglyceride (HTG) concentration were assayed to observe liver injuries induced by chronic alcohol abuse. In addition, the phenomenon of alcohol induced fatty liver were also observed by histopathological changes. Different doses of propolis ethanol extract were p.o. administered three times per day for three days, after four weeks' alcohol administration. It was found that 10 mg/kg of propolis ethanol extract significantly decreased the elevations of serum GOT, GPT, TG and HTG. In histopathological examination, 30 mg/kg of propolis ethanol extract also remarkably decreased the hepatocellular fatty degeneration, apparent as vacuolization, induced by chronic alcohol abuse.

Water Resource Protection in Taiwan: An Evaluation of the Taipei Water Management Commission

/ This study evaluates the institutional capacity and performance of the Taipei Water Management Commission. The commission, which manages the Taipei Water Special Area-one of 95 such areas in Taiwan and the only one managed by a supervisory agency-has established a record of water conservation that suggests its utility as a model for managing other protected water resources areas in Taiwan. However, its present institutional structure limits its ability deliver on its mandate. The study identifies a number of problems related to the commission's current institutional structure that need to be addressed if the commission is to serve as a viable model for managing other protected water resource areas in Taiwan.KEY WORDS: Water resources management; Commissions; Institutional capacity; Taiwan

Age differences in remote pointing performance

The purpose of this study was to investigate age differences in remote pointing movements. The subjects were recruited from three age groups (ages 18-22 yr., 40-50 yr., and 60-70 yr., with 9 men and 9 women in each group). They were required to perform cursor-positioning tasks using a remote pointing device, in which the dependent measures were the time taken to reposition the cursor and the accuracy of subjects' movement trajectories. The movement time was further separated into two components, First Submovement duration and Adjustment Submovement duration. Analysis indicated that age groups showed reduced performance on remote pointing. Moreover, remote positioning movement for the young-adult group was mostly completed in their First Submovement phase, while the elderly subjects spent most of their movement time on the Adjustment Submovement phase. These results support the proposition that different age groups exhibit different kinds of movement patterns.

Human liver CYP2B6-catalyzed hydroxylation of RP 73401

RP 73401 is a potent inhibitor of cyclic nucleotide phosphodiesterase type IV. RP 73401 is metabolized by human liver microsomes almost exclusively by transhydroxylation of the cyclopentyl group to RPR 113406. Liquid chromatography/mass spectrometry/mass spectrometry analysis of plasma from patients given RP 73401 also revealed a molecular ion and fragmentation consistent with RPR 113406. Thus, the objective was to determine the oxidative enzyme(s) responsible for RP 73401 hydroxylation. Kinetic constants of RP 113406 formation ranged from 8 to 26 MM and 0.83 to 5.99 nmol/min/mg protein for K(m) and V(max), respectively (n = 3). Enzyme activity varied 23-fold among 15 human liver microsome samples and correlated with CYP2A6-catalyzed coumarin hydroxylase (r2 = 0.85, P < .01) and CYP2B6-catalyzed 7-ethoxytrifluoromethylcoumarin O-deethylase (r2 = 0.82, P < .01) activities. Chemical inhibition studies showed a 63% decrease in RP 73401 hydroxylation by 500 microM orphenadrine. Coumarin (10 microM), however, did not inhibit RP 73401 hydroxylation. Also, anti-CYP2B1 IgG produced 85% inhibition of RP 73401 hydroxylation, but only a negligible decline in coumarin hydroxylase activity. Of the 10 expressed P450 forms studied, only CYP2B6 catalyzed RP 73401 hydroxylation. Finally, expressed CYP2B6 showed a high affinity (K(m) = 22.5 microM) for RP 73401 hydroxylation, similar to the human liver microsome studies.

The effects of ursodeoxycholic acid in patients with severe obstructive jaundice after drainage procedure

BACKGROUND

The aim of this study is to evaluate the therapeutic effect of ursodeoxycholic acid (UDCA) for patients with severe obstructive jaundice after drainage procedure.

METHODS

From September 1993 to December 1994, patients admitted with severe obstructive jaundice (serum bilirubin > 15 mg/dl) and successful drainage were enrolled into our study. They were randomly divided into two groups to receive UDCA 600 mg per day (UDCA group) or a placebo (placebo group) until operation or discharge. Bile drainage amount, clinical symptoms and signs and adverse effects of drugs were recorded daily. Biochemical tests, including albumin, total bilirubin, cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyl transpeptidase and prothrombin time, were checked first, on the third and seventh days, and then two weeks after drainage.

RESULTS

Thirty-eight patients (M/F = 36/ 2, mean age 66.6 +/- 6.4 years) completed the study, 18 in the UDCA group and 20 in the placebo group. There were no differences in age, sex, causes of obstructive jaundice or methods of drainage procedure between the UDCA and placebo groups. Improvement in biochemical test results were noted in both groups. However, bile drainage amount and changes in liver biochemical test, especially the decrement of serum bilirubin, were not significantly different between both groups.

CONCLUSIONS

UDCA seemed not to benefit patients with severe obstructive jaundice after successful drainage.

Novel and frequent mutations of hepatitis B virus coincide with a major histocompatibility complex class I-restricted T-cell epitope of the surface antigen

We examined the full-length hepatitis B virus (HBV) envelope (surface antigen or HBV small surface antigen [HBsAg]) sequences of 12 different liver samples from 10 different hepatoma-containing chronic carriers. Surprisingly, novel and frequent mutations occurred predominantly at amino acids 40 and 47 of HBsAg, in addition to within a known protective B-cell epitope (so-called group a determinant of HBsAg 124-148). Approximately 58% of chronic carriers contain mutations at the group a determinant. The mutation frequency at the hotspot codons 40 and 47 is approximately 83%, 1 order of magnitude higher than at the known polymorphic sites of subtype-specific determinants at codons 122 and 160, which is approximately 4%. This new mutational domain is found to coincide with a major histocompatibility complex class I-restricted T-cell epitope. The potential biological significance of this novel mutation in the immunopathogenesis of HBV chronic carriers is discussed.

Vitamin D stores of urban women in Taipei: effect on bone density and bone turnover, and seasonal variation

This study was performed to survey the vitamin D nutritional status of urban Chinese women, and to define its role in determining bone metabolic rate and bone mineral density (BMD). We measured serum 25-hydroxyvitamin D (25-OHD), the major storage form of vitamin D, and BMD, at the spine, hip, and total body skeleton, of 262 healthy Chinese women aged from 40 to 72 years, residing in Taipei city. Bone turnover markers, including serum osteocalcin, bone alkaline phosphatase isozyme, and C-terminal propeptide of type I procollagen, and a urinary bone resorption marker, N-terminal crosslinked fragment of type I collagen, were also measured. We found generally adequate vitamin D nutritional stores. The mean concentration of serum 25-OHD was 30.7 (SD = 8.2) ng/mL for all 262 subjects and there were no significant age-related changes. Those who had serum sampled during the summer showed higher serum 25-OHD levels (N = 138; mean +/- SD: 32.7 +/- 7.6 ng/mL) than those who had serum sampled during winter (N = 124; mean +/- SD: 28.5 +/- 8.3 ng/mL; Student's t-test, p < 0.001), but these two groups showed similar BMD and bone marker values. Those with serum 25-OHD concentration in the lowest or highest tertile did not show different BMD or bone marker values than those in the other tertiles. Multiple regression demonstrated no correlation between 25-OHD and any bone marker or BMD at any site. Thus, in this free-living urban Chinese population, in a subtropical region, we could not demonstrate a role of vitamin D stores in determining bone turnover rate or BMD in women aged 40-70 years.

Solamargine purified from Solanum incanum Chinese herb triggers gene expression of human TNFR I which may lead to cell apoptosis

Solamargine possessed a potent cytotoxicity to human hepatocyte (Hep3B) and normal skin fibroblast. The inhibition curves of solamargine to the both cells were essentially overlapped, suggesting a parallel effect for the cell death. To define mechanism of cytotoxicity of solamargine, the changes of morphology and DNA content in cells were studied. A sub-G1 cell stage was drastically increased after 3-h incubation with solamargine. The results evidence that solamargine arises cell death by apoptosis. In addition, the gene expression of TNFR I were up-regulated within 30 min of solamargine treatment. Since TNF Receptor I has been involved in apoptosis, the overexpression of TNF receptor I may be related with the mechanism of cytotoxicity of solamargine. This communication is the first report that a component of Chinese herbs triggers gene expression of human TNFR I which may lead to cell apoptosis.

Sexual differences in bone markers and bone mineral density of normal Chinese

We measured bone mineral density (BMD) at lumbar (L2-L4) vertebrae and proximal femurs of 385 healthy Chinese women aged 40-70 years and 156 healthy Chinese men aged 20-85, and four markers-bone alkaline phosphatase isozyme (BAP), procollagen-I C terminal propeptide (PICP), osteocalcin (BGP) in serum, and a bone resorption marker, urinary cross-linked N-telopeptide of type I collagen (NTX), of these subjects. The results indicate that in postmenopausal women, levels of all the markers increased with age. In men, serum BAP, PICP, and urinary NTX decreased significantly, and serum BGP decreased with borderline significance (P = 0.08). With increasing age, bone density decreased at both sites in postmenopausal women and at the proximal femur in men. The lumbar bone density showed no significant age-related changes in men. In premenopausal women, BMD at either site showed no significant change with increasing age. Despite the different trends between men and women of age-related changes in BMD and bone markers, bone density of both proximal femur and spine in both sexes correlated inversely with levels of the bone markers in a manner independent of age or body weight. The meaning of opposite age effects on bone markers in men and women needs further investigation. In addition, higher bone marker levels, implying faster bone turnover rate, are associated with lower BMD in both sexes.

Bone mineral density and bone markers in relation to vitamin D receptor gene polymorphisms in Chinese men and women

Whether vitamin D receptor gene (VDRG) polymorphism can be used as a predictor for bone turnover rate or bone mass remains controversial. Its role within various ethnic populations are also unsettled. We examined VDRG polymorphism using restrictive enzymes Bsm-I, Apa-I, and Taq-I in 155 men aged 22-88 and 113 premenopausal women aged 40-53. The bone mineral density (BMD) of the vertebrae (L2-4), proximal femur, and total body bone mineral content (tb-BMC) (women only), as well as urinary N-terminal crosslinked fragment of type I collagen (NTX), serum osteocalcin, bone isozyme of alkaline phosphatase, and caboxyterminal propeptide of type I procollagen levels were measured. Chinese men and women exhibited a low prevalence for B (absence of Bsm-I restriction site) phenotypes than white and Japanese. Within the tested samples there were 0.4% BB homozygotes, 6.7% Bb heterozygotes, and 93% bb homozygotes. The distributions of Apa-I polymorphism (9.0% AA, 42.5% Aa, and 48.5% aa) also differed from those reported for the white populations. Most of the Chinese men and women were TT homozygous (96.6%). A comparison of actual values and values adjusted for age and weight of tb-BMC and BMD at the lumbar spine, Trochanter, Ward's triangle, and femoral neck showed no significant difference among three subgroups in each of the three sets of polymorphism. Furthermore, the actual values and adjusted values (adjusted for age) of the four bone markers, respectively, showed no significant differences. We conclude that given the very low prevalence of the suspected high risk genotypes (B, A, and t), and the lack of difference among the polymorphic subgroups, VDRG polymorphism may not be an important determinant of the bone turnover rate and bone mass of Chinese men and women.

Role of viscoelasticity in the tube model of airway reopening. II. Non-Newtonian gels and airway simulation

The influence of viscoelastic gels as lining fluids on the pressure-velocity relationships in an airway tube model (Gaver et al. J. Appl. Physiol. 69: 74-85, 1990) was examined. A flow instability was observed due to the occurrence of a sol-gel transition in the viscoelastic properties under flow conditions. We further report measurements of the viscoelastic properties of airway secretions. Airway secretions are gels under small strains and have a yield stress of 4-7 dyn/cm2. Secretions from the pharyngeal airway show lower elasticity than secretions from the trachea. The airway reopening process is simulated using a Weibel lung geometry by incorporating the constitutive equations from the model gel studies and utilizing the rheological data on airway secretions. In these simulations, a "popping-open" phenomenon arises from a flow instability in airway generations 8-14 when the rheological properties of the lining fluids are assumed to be similar to those of pharyngeal secretions. On the basis of these studies, the elasticity of airway secretions plays an important role in airway reopening.

The liver biochemical tests and serological markers of hepatitis B virus in the very old-aged population in Taiwan

BACKGROUND

Human liver alters with aging. Lower serum albumin with elevation in serum cholesterol and alkaline phosphatase (ALP) has been reported in the elders, but there was no further report on the very old people (i.e., >75 Y/O). We evaluated changes of liver biochemical tests and hepatitis B virus (HBV) serological markers in the very old-aged population.

METHODS

From October 1993 to June 1994, 2,549 subjects attended our hospital for physical check-up. Of them 1,742 were healthy subjects (M/F = 1,058/648) and were enrolled for analysis of the normal range of liver biochemical tests in different age groups. They were divided into four groups; young-aged group (age between 18 and 40, n = 231), middle-aged group (age between 41 and 64, n = 991), old-aged group (age between 65 and 75, n = 424), and very old-aged group (age > or = 76, n = 96). The items of liver biochemical tests included albumin, total bilirubin, cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST), ALP and gamma-glutamyl transpeptidase (GGT). The whole population, totally 2,549 subjects, were used for the analysis of the prevalence of HBV serological markers in different age groups.

RESULTS

Serum albumin was the only biochemical parameter that persisted to decline after the age of 75 (p <0.05). Cholesterol began to elevate in the middle-age but decreased after 75 Y/O. The old-aged and very old-aged subjects had higher levels of serum bilirubin, AST, ALP, and GGT levels than the other two groups (p <0.05), however, the changes of ALT levels among these groups were not so remarkable. The HBV carrier rates in the young-aged, middle-aged, old-aged and the very old-aged groups were 16.8%, 12.3%, 6.8% and 7.0%, respectively (p <0.001). Furthermore, the very old-aged group had a significantly higher prevalence of negativity in both HBsAg and anti-HBs (p <0.001).

CONCLUSIONS

Serum albumin is the only biochemical parameter that persists to decline after the age of 75. In contrast, elevation of cholesterol tends to reverse after that age. All the aging-related changes in biochemical tests are clinically nonsignificant though some of them are significant in statistical analysis. In addition, a low HBV carrier rate and a high prevalence of negativity in both HBsAg and anti-HBs are noted in the very old-aged people, possibly due to the progressive loss of HBV markers in the elders.