Dynamic Response of Wigner Crystals

The Wigner crystal, an ordered array of electrons, is one of the very first proposed many-body phases stabilized by the electron-electron interaction. We examine this quantum phase with simultaneous capacitance and conductance measurements, and observe a large capacitive response while the conductance vanishes. We study one sample with four devices whose length scale is comparable with the crystal's correlation length, and deduce the crystal's elastic modulus, permittivity, pinning strength, etc. Such a systematic quantitative investigation of all properties on a single sample has a great promise to advance the study of Wigner crystals.

Intrinsic and extrinsic dopings in epitaxial films MnBi2Te4

The intrinsic antiferromagnetic topological insulator MnBi₂Te₄and members of its family have been the subject of theoretical and experimental research, which has revealed the presence of a variety of defects and disorders that are crucial in determining the topological and magnetic properties. This also brings about challenges in realizing the quantum states like the quantum anomalous Hall and the axion insulator states. Here, utilizing cryogenic magnetoelectric transport and magnetic measurements, we systematically investigate the effects arising from intrinsic doping by antisite defects and extrinsic doping by Sb in MnBi₂Te₄epitaxial films grown by molecular beam epitaxy. We demonstrate that the nonequilibrium condition in epitaxy allows a wide growth window for optimizing the crystalline quality and defect engineering. While the intrinsic antisite defects caused by the intermixing between Bi and Mn can be utilized to tune the Fermi level position as evidenced by a p-to-n conductivity transition, the extrinsic Sb-doping not only compensates for this doping effect but also modifies the magnetism and topology of the film, during which a topological phase transition is developed. Conflicting reports from the theoretical calculations and experimental measurements in bulk crystals versus epitaxial films are addressed, which highlights the intimate correlation between the magnetism and topology as well as the balance between the Fermi-level positioning and defect control. The present study provides an experimental support for the epitaxial growth of the intrinsic topological insulator and underlines that the topology, magnetism, and defect engineering should be revisited for enabling a steady and reliable film production.

Aging of biodegradable blended plastic generates microplastics and attached bacterial communities in air and aqueous environments

The use of biodegradable plastics (BPs) has been widely promoted in recent years, but before their complete degradation, the phase of microplastics (MPs) is inevitable. However, little information concerning the production of MPs from blended polymers is available. This study aimed to explore the characteristics of MPs produced from blended plastics and the development of biofilms on plastic surfaces under long-term aging. Here, three blended materials (i.e., PBAT (53%)+PLA (10%)+Starch (20%), PBAT (80%)+Starch (20%), HDPE (60%)+CaCO₃ (40%)) were aged for 90 days in air, deionized (DI) water and seawater. The results showed massive production of MPs (9653 ± 3920-20,348 ± 5857 items/g) from blended plastics accompanied by a large quantity of flocculent substances during 90 days aging period. Furthermore, the richness of bacteria communities on hydrophobic plastics (i.e., PBAT (53%)+PLA (10%)+Starch (20%), PBAT (80%)+Starch (20%)) was higher than hydrophilic plastics (i.e., HDPE (60%)+CaCO₃ (40%)), and bacterial communities attached to blended plastics exhibited significantly variation with aging times. Overall, promoting the marketable application of blended plastics is risky if their environmental behavior is not effectively addressed.

[Effect of phacoemulsification on the Berger space]

Objective: To investigate the effect of phacoemulsification on the Berger space (BS). Methods: A prospective cohort study. Patients with cataract who underwent phacoemulsification and intraocular lens implantation in the Department of Ophthalmology, Affiliated Hospital of Nantong University from May 2021 to October 2021 were enrolled. The BS was observed by slit-lamp microscopy and anterior segment optical coherence tomography (AS-OCT) before and 1 month after operation. Intraoperative optical coherence tomography with a 25G optical fiber was performed to observe the BS. The number of eyes with the BS and materials in the BS (MIB) detected perioperatively was counted, and the width of the BS was measured. Statistical analysis was carried out by the Chi-square test, generalized estimating equations, Mann-Whitney U test and binary logistic regression analysis. Results: A total of 119 patients (119 eyes) were included [44 males, 75 females; mean age, (65±12) years]. Preoperatively, the BS was identified in only 4 eyes (3.4%), and no MIB was found. Intraoperatively, the BS was identified in 47 eyes (39.5%), and the MIB was observed in 20 eyes (16.8%). At one month postoperatively, the BS was identified in 33 eyes (27.7%), of which 16 eyes (13.4%) still had MIB. There were significant differences in the detection rates of the BS and MIB between intraoperative and preoperative groups (both P<0.001). The difference in the detection rate of the BS postoperatively compared to intraoperatively was statistically significant (P=0.001), while the difference in the detection rate of MIB was not statistically significant (P>0.05). The intraoperative and postoperative width of the BS [M (Q₁, Q₃)] was 160.3 (61.6, 273.1) μm and 106.8 (0, 259.4) μm, respectively, and the difference was statistically significant (Z=-2.28, P=0.023). In addition, the detection rate of the BS and MIB in patients with a high risk of zonular fiber weakness [60.7% (17/28) and 42.9% (12/28)] was significantly higher than that in patients without this risk factor [33.0% (30/91) and 8.8% (8/91)] (χ²=6.90, P=0.009; P<0.001). In the multivariable model, weakness of zonular fibers (OR=0.214, 95%CI: 0.081 to 0.561) and higher cumulative dissipated energy (OR=1.255, 95%CI: 1.047 to 1.504) were the main risk factors for structural changes of the BS intraoperatively. Conclusion: Phacoemulsification can damage the normal anatomical structure of the BS, resulting in intraoperative entrance of fluid and particulates to the BS.

[Analysis of 2 diagnostic criteria of echocardiography for coronary artery aneurysm in Kawasaki disease]

Objective: To analyze the difference between Z score and previous criteria in the diagnosis characteristics of coronary artery aneurysm (CAA) in Kawasaki disease, and to investigate the clinical distribution of Kawasaki disease CAA in the Z score group. Methods: This study retrospectively analyzed the clinical and echocardiographic data of 2 419 children with Kawasaki disease in Shenzhen Children's Hospital from January 2009 to December 2019. The traditional criteria and Z score criteria were used to diagnose CAA, and the differences of diagnostic efficiency between the 2 diagnostic methods were analyzed. The clinical distribution characteristics of CAA in children with Kawasaki disease were analyzed by grouping their sex, clinical classification (complete Kawasaki disease, incomplete Kawasaki disease) the sensitivity to intravenous immunoglobulin (IVIG) (IVIG-sensitive Kawasaki disease,IVIG-unresponsive Kawasaki disease). And the course of the disease (≤6 weeks, >6-8 weeks, >8 weeks to 6 months) etc. The χ² test or Kruskal-Wallis test was used for comparison between the groups, and the Kappa test was used for consistency evaluation. Results: Among the 2 419 children with Kawasaki disease, 1 558 were males and 861 were females. The age of onset was 1.8 (1.0, 3.2) years. The rate of CAA by Z score criteria was higher than that by traditional method (21.9% (529/2 419) vs. 13.9% (336/2 419), χ²=1 074.94, P<0.001). Compared to the traditional method, the Z score criteria found higher rate of CAA in male patients, patients with incomplete Kawasaki disease, and IVIG-unresponsive patients (25.2% (392/1 558) vs. 16.0% (249/1 558), (32.7% (166/507) vs. 19.5% (99/507), 30.5% (95/312) vs. 24.0% (75/312), χ²=694.05, 216.19, 184.37, all P<0.001). The Z score criteria was consistent with the traditional method in diagnosing CAA (κ=0.642,P<0.001). Moreover, in the Z score criteria, the rate of CAA in males (25.2%, 392/1 558) was higher than that in females (15.9%, 137/861), higher in incomplete Kawasaki cases (32.7%, 166/507) than that in complete Kawasaki case (19.0%, 363/1 912), and higher in IVIG-unresponsive cases (30.4%, 95/312) than that in IVIG-sensitive cases (20.6%, 434/2 107), with statistically significant differences (χ²=27.76, 44.38, 15.43, all P<0.001). Coronary Z score of course ≤ 6 weeks was greater than that of course between>6-8 weeks and >8 weeks to 6 months (1.3 (0.7, 2.3) vs. 0.7 (0.3, 1.4), 0.7 (0.3, 1.3), Z=20.65, 13.70, both P<0.001). Conclusions: The rate of CAA in Kawasaki disease by Z score criteria is higher than that by traditional method. In the Z score group, most CAA occur within 6 weeks of the course of the disease, and the rate of CAA in male, incomplete Kawasaki disease, and IVIG-unresponsive is higher.

High precision, low excitation capacitance measurement methods from 10 mK to room temperature

Capacitance measurement is a useful technique in studying quantum devices, as it directly probes the local particle charging properties, i.e., the system compressibility. Here, we report one approach that can measure capacitance from mK to room temperature with excellent accuracy. Our experiments show that such a high-precision technique is able to reveal delicate and essential properties of high-mobility two-dimensional electron systems.

[The status quo and analysis of quality control of cancer chemotherapy in 76 hospitals in Beijing]

Objective: Investigated the status quo of quality control of cancer chemotherapy in hospitals in Beijing to discover the main problems and provide the improvement measures. Methods: One medical record of cancer chemotherapy was taken every month for examination of quality control, and a total of 10 medical records in each hospital were examined. A total of 756 medical records from 76 hospitals were examined. Results: The results of analysis showed that the overall standardization and quality control of cancer chemotherapy was positively correlated with the grade of hospital. Only 36.8% of the hospitals were equipped with Pharmacy Intravenous Admixture Services (PIVAS). In terms of quality control of chemotherapy and medicine, the department of oncology had better performance than other departments (P<0.01). The scores of quality control of chemotherapy and medicine in the hospitals with clinical specialist pharmacists were 50.6 and 14.5, significantly higher than 47.2 and 12.7 of those without clinical specialist pharmacists (P<0.05). Conclusion: We should focus on the quality control of cancer chemotherapy in secondary hospitals, reinforce the training of oncology specialists, establish the admission system of oncologists, enhance the training of oncology clinical pharmacists and promote the standardization of cancer chemotherapy.

The effects of power on–off durations of pulsed ultrasound on the destruction of cancer cells

PURPOSE

Low-intensity ultrasound irradiation is a potential method for suppressing cancer cell proliferation, inducing apoptosis and delivering specific cytotoxic genes or drugs into tumors topographically in future cancer therapies. However, ultrasound attenuates rapidly in tissue and produces heat. Pulsed ultrasound is frequently used to minimize pain and possible thermal damage to the surrounding normal tissue during therapy, since it results in smaller temperature increases. This study compared three pulsed-ultrasound strategies for destroying cancer cells, measuring their induced temperature increases to determine the optimal pulsing parameters.

MATERIALS AND METHODS

We performed three types of experiment, involving ultrasound with (1) a fixed duty cycle of 50% with variable on- and off-times, (2) a fixed off-time with variable on-times, and (3) a fixed on-time with variable off-times.

RESULTS

The results show that for different types of cultured cells (HeLa, HT-29, Ca9-22 and fibroblast) exposed to ultrasound of the same frequency (1 MHz) and energy, long pulses combined with off-times that are 5-10 times longer (on-/-off-times pairs of 5/25, 25/250, or 250/2500 ms/ms) cause significant cell destruction whilst avoiding temperature increases of more than 1.5 degrees C. Furthermore, the correlation between the temperature increase and the percentage of surviving cells is low.

CONCLUSIONS

Pulsed ultrasound with a long on-time and an even longer off-time exerts a high cytotoxic effect but a smaller temperature increase compared with non-pulsed ultrasound. This indicates that the cytotoxic effects observed in the current study were not purely due to the thermal effects of the ultrasound.

[A biomechanical study of anterior screw fixation for type II odontoid fracture with anteroinferior-posterosuperior fracture line]

OBJECTIVE

To investigate the biomechanical effect of anterior screw fixation on the type II fractured odontoid process.

METHODS

Twenty fresh human C1-C2 vertebrae specimens were harvested and randomly divided into three groups. The angle of type II fracture line was 0 degree in group I (n=6), 17 degrees in group II (n=8) and 25 degrees in group III (n=6). The fractures were treated by anterior screw fixation. Insertion torque,maximal axial pullout force and stiffness of the bone-screw were tested.

RESULTS

There was no significant difference of screw insertion torque and the pull-out strength between each group. The displacement of the odontoid fragment had an association to the angle of the fracture line,the displacement of the small angle was significantly higher than that of the large one (P < 0.5). No significant difference of structure stiffness of the bone-screw was found between each group.

CONCLUSION

Anterior screw fixation is feasible for type II odontoid fracture with certain fracture line extends from anteroinferior to posterosuperior.

Observation of organochlorine pesticides in the air of the Mt. Everest region

High mountains have been suggested to play an important role in the global transport of persistent organic pollutants, yet observation of these pollutants in high mountains is very limited. In the summer of 2002, air samples were collected at Dingri at a height of 4400 m above sea level (m a.s.l.) and at Rongbuk Valley (4976 m a.s.l.) in the Mt. Everest region and analyzed using large volume injection gas chromatography tandem mass spectrometry. The mean concentrations of organochlorine pesticides (OCPs) in the samples were 19.2, 11.2, 7.7, 8.9, 10.4, 27.6, 5.1, 5.1, and 3.7 pg m(-3) for alpha-HCH, beta-HCH, gamma-HCH, HCB, heptachlor, alpha-endosulfan, p,p'-DDE, o,p'-DDT, and p,p'-DDT, respectively. Backward trajectories were used to assess the association between source regions, transport paths, and observed OCP concentrations. During the sampling period, the o,p'-DDT/p,p'-DDT concentration ratios were observed to be between 1.23 and 1.41, much higher than that of technical DDT, indicating the existence of a DDT source other than technical DDTs in the source regions.

Oligoclonal T cells are infiltrating the brains of children with AIDS: sequence analysis reveals high proportions of identical beta-chain T-cell receptor transcripts

We have recently described the presence of perivascular CD3+ CD45RO+ T cells infiltrating the brains of children with AIDS. To determine whether these infiltrates contain oligoclonal populations of T cells, we amplified by PCR beta-chain T-cell receptor (TCR) transcripts from autopsy brains of four paediatric patients with AIDS. The amplified transcripts were cloned and sequenced. Sequence analysis of the beta-chain TCR transcripts from all four patients revealed multiple identical copies of TCR beta-chain transcripts, suggesting the presence of oligoclonal populations of T-cells. These TCR transcripts were novel. The presence of oligoclonal populations of T cells in the brains of these four paediatric patients with AIDS suggests that these T cells have undergone antigen-driven proliferation and clonal expansion very likely in situ, in the brains of these AIDS patients, in response to viral or self-antigens. Although the specificity of the clonally expanded beta-chain TCR transcripts remains to be elucidated, none of the beta-chain TCR transcripts identified in this study were identical to those specific for HIV-1 antigens that are currently reported in the GENBANK/EMBL databases. Certain common CDR3 motifs were observed in brain-infiltrating T cells within and between certain patients. Large proportions (24 of 61; 39%) of beta-chain TCR clones from one patient (NP95-73) and 2 of 27 (7%) of another patient (NP95-184-O) exhibited substantial CDR3 homology to myelin basic protein (MBP)-specific TCR derived from normal donors or TCR expressed in the brain of patients with multiple sclerosis (MS) or with viral encephalitis. These two patients (NP95-73 and NP95-184-O) also shared HLA class II with the normal donors and the MS patients who expressed these homologous TCR. Pathologic examination at autopsy of the brains revealed the presence of myelin pallor only in patient NP95-73. T-cell clones identified in the brain of patients NP95-73 and NP95-184-O may recognize MBP or another CNS self antigen and this recognition may be restricted by either DRB1*15 or DQB1*0602 specificities.

Pilot point temperature regulation for thermal lesion control during ultrasound thermal therapy

The fundamental goal of ultrasound thermal therapy is to provide proper thermal lesion formations for effective tumour treatment. The quality of the therapy depends mostly on its positional precision. To date, most ultrasound thermal therapy treatments have focused on the formation of power or temperature patterns. The non-linear and time-delay effects of thermal dose formation prohibit direct control of the thermal dose distribution. In the paper, the control of thermal lesions by regulation of the temperature of a pilot point is proposed. This scheme utilises the high correlation between temperature elevation and thermal dose at the forward boundary of thermal lesions. To verify the feasibility, a 2D ultrasound phased array system was used to generate thermal lesions of various sizes, and the temperature elevation required to generate a thermal dose threshold was investigated. Results showed that the required temperature elevation was found to be a reasonably constant value of 52.5 degrees C under differing conditions when the focal area was small. When the focal area under consideration was large, the required temperature elevation became a monotonic function of blood perfusion rate, ranging from 49.2 to 52.5 degrees C. When the reference temperature of the pilot point was set at a conservative value (52.5 degrees C), the thermal lesions were controlled precisely under a wide range of blood perfusion and power pattern changes, tested by using a more realistic model that takes into account thermal-induced attenuation and blood perfusion changes. This changed the complex thermal dose control problem into a simple temperature regulation problem, which makes implementation of thermal lesion control easier, giving the scheme a high potential for application to current ultrasound thermal therapy systems.

Prostaglandin E2 is involved in the increase of cytochrome P-450 2B1 expression by alpha-tocopheryl succinate in primary rat hepatocytes in the presence of phenobarbital

The modulation of cytochrome P-450 2B1 expression by alpha-tocopheryl succinate and whether prostaglandin E2 is involved in this modulation in primary rat hepatocytes in the presence of phenobarbital were investigated. A primary rat hepatocyte culture model that faithfully reproduces the phenobarbital response observed in vivo was used. Intracellular alpha-tocopherol content was dose dependently increased by alpha-tocopheryl succinate incubation. Hepatocytes were demonstrated to have prostaglandin E2-synthesizing capability. alpha-Tocopheryl succinate inhibited prostaglandin E2 synthesis by hepatocytes and increased cytochrome P-450 2B1 expression in the presence of phenobarbital; however, it had little effect on intracellular cAMP level. To mimic the exogenous source of prostaglandin E2 from nonparenchymal cells, various concentrations of prostaglandin E2 were added to the cell culture. High doses of exogenous prostaglandin E2 (100 and 1,000 nM) inhibited the cytochrome P-450 2B1 expression in the presence of phenobarbital compared with low doses (1 and 10 nM); however, the presence of high doses of prostaglandin E2 had no effect on intracellular cAMP level. Forskolin significantly increased intracellular cAMP level and inhibited cytochrome P-450 2B1 expression in the presence of phenobarbital. The results of this study indicate that alpha-tocopheryl succinate increases cytochrome P-450 2B1 expression via its inhibition of prostaglandin E2 synthesis in the presence of phenobarbital; however, changes in intracellular cAMP level are not related to cytochrome P-450 2B1 expression.

Suppression of altered hepatic foci development by a high fish oil diet compared with a high corn oil diet in rats

Effects of low corn oil, high corn oil, and high fish oil diets on altered hepatic foci development in female Sprague-Dawley rats were investigated. Rats assigned to Groups 1-4 were initiated with saline as the control and those assigned to Groups 5-7 were initiated with diethylnitrosamine (DEN 15 mg/kg) at 24 hours of age. After weaning, all rats, except those in Group 1, received 500 ppm phenobarbital (PB) in their diet as tumor promoter for three months. Altered hepatic foci development was significantly lower in DEN-initiated rats fed the high fish oil + PB diet than in DEN-initiated rats fed the high corn oil + PB diets. Liver weight and relative liver weight were significantly greater in rats fed the high fish oil + PB diet than in rats fed the other diets, and hepatic biotransformation/detoxification enzyme activities were greater in rats fed the fish oil + PB diets than in rats fed the other diets. These results suggest that the effect of a high fish oil diet on altered hepatic foci may occur through regulation of hepatic biotransformation/detoxification enzyme activities, leading to alteration in the tumor-promoting action of PB. Dietary lipid significantly affected the hepatic phospholipid fatty acid composition of rats. n-3 polyunsaturated fatty acids were incorporated into membrane phospholipid at the expense of n-6 polyunsaturated fatty acids. A high fish oil diet caused greater oxidative stress in rats, as measured by plasma vitamin E level, red blood cell glutathione status, liver lipid peroxidation, and hepatic glutathione reductase activity. Pearson's correlation analysis indicated that the foci number was negatively correlated to the liver thiobarbituric acid-reactive substance and 7-pentoxyresorufin O-dealkylase activity, and the foci area was negatively correlated to the liver thiobarbituric acid-reactive substance activity (p < 0.05) in rats of groups that developed foci. These results suggest that the type of dietary lipid is the more important determinant for gamma-glutamyl transpeptidase-positive foci development than the amount of dietary lipid when rats consumed approximately the same amount of calories in all the dietary groups, and the underlying mechanisms may be partially ascribed to the antioxidant/oxidation status and biotransformation/detoxification system of rats.

Mutagenesis of the rapamycin producer Streptomyces hygroscopicus FC904

Rapamycin (RPM) is produced by Streptomyces hygroscopicus FC904 isolated from soil in Fuzhou, China. It is a triene macrolide antibiotic with potential application as an immunosuppressant and drug for human gene therapy. In an attempt to improve rapamycin production, mutation and screening of the parent culture have been carried out. Thousands of survivors were obtained after mutagenesis by NTG (3 mg/ml) and UV (30 W, 15 cm, 30 seconds) of spore suspensions. None showed improved production of RPM. We determined the susceptibility to antibiotics of S. hygroscopicus FC904 by two fold dilutions of antibiotics in oatmeal agar plates. It was found that the strain was resistant to penicillin, erythromycin, RPM, tetracycline and chloramphenicol, but susceptible to mitomycin C (MIC, 10 microg/ml) and aminoglycosides such as gentamicin (MIC, 0.1 microg/ml), kanamycin (MIC, 0.1 microg/ml) and streptomycin (MIC, 0.3 microg/ml). Protoplasts of strain FC904 were prepared after finding the best conditions for their formation. They were treated with gentamicin, erythromycin, mitomycin C and NTG. Surprisingly, gentamicin was especially effective for obtaining higher RPM-producing mutants. Mutant C14 was selected by exposing the protoplasts of the parent strain FC904 to 1 microg/ml of gentamicin at 28 degrees C for 2 hours. A higher RPM-producing mutant (C14-1) was obtained from the protoplasts of mutant C14 treated with gentamicin, and its titer was 60% higher than that of the parent strain FC904 by HPLC analysis. Another improved mutant (C14-2) was obtained from the spores of mutant C 14 treated with 1 microg/ml of gentamicin plus 2 mg/ml of NTG at 28 degrees C for 2 hours. Mutant C14-2 had a titer 124% higher than FC904. The possible mechanism for the effect of gentamicin by using protoplasts or spore suspensions will be discussed, i.e. the possibility of gentamicin being a mutagen or a selective agent.

Optimization of power deposition and a heating strategy for external ultrasound thermal therapy

The purpose of this paper is to examine the thermal dose distribution, to configure the optimal absorbed power deposition, and to design an appropriate heating strategy for ultrasound thermal therapy. This work employs simulation programs, which are based on the transient bio-heat transfer equation and an ideal absorbed power deposition or an ideal temperature elevation within a cube of tissue, to study the optimal absorbed power deposition. Meanwhile, a simplified model of a scanned ultrasound transducer power deposition (a cone with convergent/divergent shape) is used to investigate the heating strategy for a large tumor with a sequence of heating pulses. The distribution of thermal dose equivalence defined by Sapareto and Dewey is used to evaluate the heating result for a set of given parameters. The parameters considered are the absorbed power density, heating duration, temperature elevation, blood perfusion, and the size of heating cube. The results demonstrate that the peak temperature is the key factor determining the thermal dose for this short-duration heating. Heat conduction has a very strong influence on the responses of temperature and thermal dose for a small heating cube and the boundary portion of a large heating cube. Hence, for obtaining the same therapeutic result, a higher power density is required for these two conditions to compensate the great temperature difference between the heating cube and the surrounding tissue. The influence of blood perfusion on the thermal dose is negligible on the boundary portion of the heating cube, while in the central portion it may become a crucial factor as a lower power density is used in this portion to save the delivered energy. When using external ultrasound heating method to treat a large tumor, the size of heating unit, the sequence of heating pulses, and the cooling-time interval between the consecutive heating pulses are the important factors to be determined to have an appropriate treatment within a reasonable overall treatment time.

Presence of oligoclonal T cells in cerebrospinal fluid of a child with multiphasic disseminated encephalomyelitis following hepatitis A virus infection

We have investigated the clonality of beta-chain T-cell receptor (TCR) transcripts from the cerebrospinal fluid (CSF) and peripheral blood from a 7-year old child who developed a multiphasic disseminated encephalomyelitis following an infection with hepatitis A virus. We amplified beta-chain TCR transcripts by nonpalindromic adaptor (NPA)-PCR-Vbeta-specific PCR. TCR transcripts from only five Vbeta families (Vbeta13, Vbeta3, Vbeta17, Vbeta8, and Vbeta20) were detected in CSF. The amplified products were combined, cloned, and sequenced. Sequence analysis revealed in the CSF substantial proportions of identical beta-chain of TCR transcripts, demonstrating oligoclonal populations of T cells. Seventeen of 35 (48%) transcripts were 100% identical, demonstrating a major Vbeta13.3 Dbeta2.1 Jbeta1.3 clonal expansion. Six of 35 (17%) transcripts were also 100% identical, revealing a second Vbeta13 clonal expansion (Vbeta13.1 Dbeta2.1 Jbeta1.2). Clonal expansions were also found within the Vbeta3 family (transcript Vbeta3.1 Dbeta2.1 Jbeta1.5 accounted for 5 of 35 transcripts [14%]) and within the Vbeta20 family (transcript Vbeta20.1 Dbeta1.1 Jbeta2.4 accounted for 3 of 35 transcripts [8%]). These results demonstrate the presence of T-cell oligoclonal expansions in the CSF of this patient following infection with hepatitis A virus. Analysis of the CDR3 motifs revealed that two of the clonally expanded T-cell clones exhibited substantial homology to myelin basic protein-reactive T-cell clones. In contrast, all Vbeta TCR families were expressed in peripheral blood lymphocytes. Oligoclonal expansions of T cells were not detected in the peripheral blood of this patient. It remains to be determined whether these clonally expanded T cells are specific for hepatitis A viral antigen(s) or host central nervous system antigen(s) and whether molecular mimicry between hepatitis A viral protein and a host protein is responsible for demyelinating disease in this patient.

Enhanced neurofibrillary degeneration in transgenic mice expressing mutant tau and APP

JNPL3 transgenic mice expressing a mutant tau protein, which develop neurofibrillary tangles and progressive motor disturbance, were crossed with Tg2576 transgenic mice expressing mutant beta-amyloid precursor protein (APP), thus modulating the APP-Abeta (beta-amyloid peptide) environment. The resulting double mutant (tau/APP) progeny and the Tg2576 parental strain developed Abeta deposits at the same age; however, relative to JNPL3 mice, the double mutants exhibited neurofibrillary tangle pathology that was substantially enhanced in the limbic system and olfactory cortex. These results indicate that either APP or Abeta influences the formation of neurofibrillary tangles. The interaction between Abeta and tau pathologies in these mice supports the hypothesis that a similar interaction occurs in Alzheimer's disease.

Induction of apoptosis by esculetin in human leukemia cells

Esculetin, a coumarin compound, has been shown to exhibit antioxidant and anti-inflammatory effects. In the present study, esculetin was found to inhibit the survival of human promyelocytic leukemia HL-60 cells in a concentration-dependent and time-dependent manner. HL-60 cells underwent internucleosomal DNA fragmentation and morphological changes characteristic of apoptosis after a 24-h treatment with esculetin (100 microM). Flow cytometric analysis showed that the hypodiploid nuclei of HL-60 cells were increased to 40.93% after a 36-h treatment with esculetin (100 microM). Further investigation showed that esculetin induced the release of cytochrome c from mitochondria into cytosol in a time-dependent and concentration-dependent manner. Moreover, esculetin application reduced Bcl-2 protein expression to 58% after 9 h as compared with that time at 0. Cysteine protease 32 kDa proenzyme (CPP32), a caspase 3, was activated and its substrate, poly (adenosine diphosphate-ribose) polymerase, was cleaved after a 24-h treatment of HL-60 cells with esculetin. These data suggest that esculetin induces apoptosis in human leukemia cells by increasing cytosolic translocation of cytochrome c and activation of CPP32.

Identification of vacuolar serine proteinase as a major allergen of Aspergillus fumigatus by immunoblotting and N-terminal amino acid sequence analysis

Aspergillus species are common airborne fungi that have been identified as causative agents of extrinsic bronchial asthma. More than 10 allergens from A. fumigatus have been recently characterized by cDNA cloning. The objective of this study is to identify A. fumigatus allergens through immunoblot analysis using sera from asthmatic patients. IgE-binding components of A. fumigatus and IgE cross-reactivity among allergens of different prevalent airborne fungal species were analysed by immunoblot and immunoblot inhibition, respectively, using sera from asthmatic patients. The N-terminal amino acid sequences of major allergens identified were determined by Edman degradation. Among two batches (70 and 41 sera) of asthmatic sera tested, 19 (27%) and 14 (34%), respectively, have IgE immunoblot reactivity towards components of A. fumigatus. A 34-kDa protein that reacts with IgE antibodies in 15 (79%) and 11 (79%) of the 19 and 14 positive samples, respectively, may be considered a major allergen of A. fumigatus. The N-terminal amino acid sequences of the 34 kDa major allergen and the 30.5 and 30 kDa IgE-binding components of A. fumigatus showed sequence identity to that of the vacuolar serine proteinase from A. fumigatus. The results from immunoblot inhibition show IgE cross-reactivity among major allergens of A. fumigatus, P. notatum and P. oxalicum. Results obtained suggest that the 34 kDa major allergen of A. fumigatus may be a vacuolar serine proteinase. There is IgE cross-reactivity among serine proteinase allergens of A. fumigatus, P. notatum and P. oxalicum.

cDNA cloning and immunologic characterization of Pen o 18, the vacuolar serine protease major allergen of Penicillium oxalicum

Penicillium species are prevalent indoor airborne fungi that have been identified as causative agents of human extrinsic bronchial asthma. In the preparation of standardized diagnostic reagents, it is imperative to define the allergens of these ubiquitous fungi. Results from our previous study on P. oxalicum suggest that the 34-kd major immunoglobulin E-reacting component of this prevalent Penicillium species is probably a vacuolar serine protease. The purpose of the present study was to define this major P. oxalicum allergen (Pen o 18) through cDNA cloning and immunologic characterization. The cDNA of Pen o 18 was isolated through a combination of reverse transcriptase-polymerase chain reaction and 5'- and 3'-rapid amplification cDNA ends reactions. The primers used in these reactions were constructed according to the internal amino acid sequences of Pen o 18 and the conserved amino acid sequences of fungal serine proteases. Our results showed that a 1897-bp cDNA with an open reading frame of 503 residues was isolated for the proenzyme of Pen o 18. The encoded protein has a 16-residue signal peptide and a 119-residue prosequence. On maturation, the protein has an N-terminal glutamate that is the 136th residue encoded by the cDNA. Apparently the precursor also undergoes C-terminal processing with the cleavage of about 47 amino acids. The cDNA for Pen c 18 (the vacuolar serine protease allergen from P. citrinum ) was also isolated for comparison. Contrary to a previous report, the C-terminal region of Pen c 18 is similar to that of Pen o 18. Recombinant proteins (rPen o 18 and rPen c 18) with the putative mature N-termini and a his-tag were obtained by expressing the corresponding cDNAs in Escherichia coli. Serum samples from 7 asthmatic patients with immunoglobulin E reactivity to the 34-kd component of P. oxalicum also react to his-tagged recombinant Pen o 18. The presence of immunoglobulin E cross-reactivity between rPen o 18 and rPen c 18 was detected by immunoblot inhibition. Two monoclonal antibodies (PCM39 and FUM20) against fungal serine proteases react with rPen o 18, rPen c 18, and the 35/34-kd components in the corresponding crude fungal extracts. These components also react with immunoglobulin E antibodies in serum samples from asthmatic patients. In conclusion, results obtained confirm that the 34-kd major allergen of P. oxalicum is a vacuolar serine protease. The cDNAs of Pen o 18 and Pen c 18 encode precursor molecules that appear to undergo both N-terminal and C-terminal processing. Constructs beginning with mature N-terminal can be expressed in E. coli to produce recombinant polypeptides that are reactive to monoclonal antibodies or immunoglobulin E antibodies in serum samples from asthmatic patients. Results obtained may provide useful information and materials for preparation of standardized diagnostic reagents in clinical mold allergy.

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.

Production and characterization of monoclonal antibodies to serine proteinase allergens in Penicillium and Aspergillus species

BACKGROUND

Alkaline and/or vacuolar serine proteinases are major allergens in prevalent airborne Penicillium and Aspergillus species.

OBJECTIVE

The object of this study is to generate and characterize monoclonal antibodies against these serine proteinase allergens.

METHODS

BALB/c mice were immunized individually with the Penicillium citrinum culture medium or the crude extract and culture medium preparations of Aspergillus fumigatus. Hybridoma cells that secrete monoclonal antibodies against serine proteinase allergens were selected by immunoblotting. Antigens in three different Penicillium (P. citrinum, P. notatum and P. oxalicum) and two different Aspergillus species (A. fumigatus, and A. flavus) recognized by these monoclonal antibodies were analysed by sodium dodecyl sulphate and two-dimensional polyacrylamide gel electrophoresis immunoblotting and N-terminal amino acid sequence analysis.

RESULTS

Four (PCM8, PCM10, PCM16 and PCM39) and one (FUM20) monoclonal antibodies against serine proteinase allergens were generated after fusion of NS-1 cells with spleen cells obtained from BALB/c mice immunized with antigens from P. citrinum and A. fumigatus, respectively. Immunoblotting results showed that PCM8 reacted with an alkaline serine proteinase allergen in P. citrinum and P. notatum. PCM10 and PCM39 reacted with the alkaline serine proteinase in two Penicillium (P. citrinum, P. notatum) and two Aspergillus species (A. fumigatus, and A. flavus) tested. PCM16 reacted with the alkaline serine proteinase allergen in P. citrinum, A. fumigatus and A. flavus but not with that in P. notatum. MoAb FUM20 reacted with the alkaline serine proteinase allergen in two Aspergillus species (A. fumigatus and A. flavus) but not with that in two different Penicillium species (P. citrinum, P. notatum) tested. Among these five monoclonal antibodies generated, only PCM39 and FUM20 can react with the vacuolar serine proteinase allergen in P. notatum, P. oxalicum and in A. fumigatus. The 35 kDa P. citrinum component that reacted with FUM20 has an N-terminal amino acid sequence of DSPSVEKNAP.

CONCLUSION

Five monoclonal antibodies against different epitopes of the serine proteinase major allergens in prevalent Penicillium and Aspergillus species were generated in the present study. Antibodies obtained may be useful in the characterization and standardization of serine proteinase allergens in crude fungal extracts.

Inhibitory effect of esculetin on oxidative damage induced by t-butyl hydroperoxide in rat liver

Increasing evidence regarding free radical-generating agents and inflammatory processes suggests that accumulation of reactive oxygen species can cause hepatotoxicity. A short-chain analog of lipid hydroperoxide, t-butyl hydroperoxide (t-BHP), can be metabolized to free radical intermediates by cytochrome P-450 in hepatocytes, which in turn can initiate lipid peroxidation, affect cell integrity and result in cell injury. In this study, we used t-BHP to induce hepatotoxicity in vitro and in vivo and determined the antioxidative bioactivity of esculetin, a coumarin compound. Our investigations showed that pretreatment with esculetin (5-20 microg/ml) significantly decreased the leakage of lactate dehydrogenase (LDH) and alanine transaminase (ALT), and also decreased the formation of malondialdehyde (MDA) in primary cultured rat hepatocytes induced by a 30-min treatment with t-BHP. An in vivo study in rats showed that pretreatment with esculetin (i.p.) at concentrations of 0.5 and 5 mg/kg for 5 days before a single i.p. dose of t-BHP (0.1 mmol/kg) significantly lowered the serum levels of the hepatic enzyme markers (ALT and AST) and reduced oxidative stress in the liver. Histopathological evaluation of the rat livers revealed that esculetin reduced the incidence of liver lesions induced by t-BHP, including hepatocyte swelling, leukocyte infiltration, and necrosis. Based on the results described above, we speculate that esculetin may play a chemopreventive role via reducing oxidative stress in living systems.

Coronary arteries from human cardiac allografts with chronic rejection contain oligoclonal T cells: persistence of identical clonally expanded TCR transcripts from the early post-transplantation period (endomyocardial biopsies) to chronic rejection (coronary arteries)

Chronic cardiac allograft rejection presents pathologically as graft arteriosclerosis (GA) characterized by recipient T cell and monocyte infiltration. To determine whether oligoclonal T cells are present in coronary arteries of cardiac allografts from patients with GA, we conducted sequencing analysis of beta-chain TCR transcripts from these explanted coronary arteries using the nonpalindromic adaptor-PCR. Substantial proportions of identical beta-chain TCR transcripts in three of five patients were observed, clearly demonstrating the presence of oligoclonal T cells. TCR transcripts from the arteries of two other patients were relative heterogeneous. High proportions of identical CDR3 beta-chain TCR motifs were found in each patient. GENEBANK/EMBL/SWISS PROT database comparison of all sequences revealed that these beta-chain TCR transcripts were novel. Using Vbeta-specific PCR (independent amplification), we found in patient GA03 that the TCR transcript that was clonally expanded in the left anterior descending artery after nonpalindromic adaptor-PCR was also clonally expanded in the right coronary artery of the same allograft. These results demonstrate that this TCR transcript was clonally expanded at different anatomic sides of the cardiac allograft in a systemic manner. In two patients identical beta-chain TCR transcripts that were found to be clonally expanded in the coronary arteries of their explanted cardiac allografts were also found to be clonally explanted in endomyocardial biopsies collected 17 and 21 mo earlier from each patient. The presence of oligoclonal populations of T cells in the rejected graft suggest that these T cells have undergone specific Ag-driven proliferation and clonal expansion early on within the graft and persist throughout the post-transplantation period.

Comparison of the effect of fish oil and corn oil on chemical-induced hepatic enzyme-altered foci in rats

The effects of fish oil and corn oil diets on diethylnitrosamine initiation/phenobarbital promotion of hepatic enzyme-altered foci in female Sprague-Dawley rats were investigated. Groups of 12 rats were initiated with diethylnitrosamine (15 mg/kg) at 24 h of age. After weaning, they received diets containing either 13.5% fish oil plus 1. 5% corn oil or 15% corn oil for 24 weeks. Rats fed fish oil had significantly greater liver weight, relative liver weight, spleen weight, and relative spleen weight than rats fed corn oil (p < 0.05). Hepatic phospholipid fatty-acid profile was significantly affected by the type of dietary lipid. The rats fed fish oil had significantly greater hepatic phospholipid 20:5 and 22:6 than rats fed corn oil; in contrast, the rats fed corn oil had significantly greater hepatic phospholipid 18:2 and 20:4 than rats fed fish oil (p < 0.05). Rats fed fish oil had significantly lower hepatic vitamin E and PGE(2) content but significantly greater hepatic lipid peroxidation than rats fed corn oil (p < 0.05). The hepatic levels of antioxidant enzymes (GSH reductase and GST) were significantly greater in rats fed fish oil than in rats fed corn oil (p < 0.05). Except for PGST-positive foci (foci area/tissue area), all the other foci parameters (GGT-positive foci area/tissue area, GGT-positive foci no./cm(2), GGT-positive foci no./cm(3), PGST-positive foci no. /cm(2), and PGST-positive foci no./cm(3)) measured in the fish oil group were 10-30% of those in the corn oil group (p < 0.05). Analyses of Pearson correlation coefficient revealed a positive correlation between hepatic GGT- or PGST-positive foci number (no. /cm(2)) and PGE(2) content (r = 0.66, P = 0.01; r = 0.56, P = 0.02, respectively) but a negative correlation between GGT- and PGST-positive foci (no./cm(2)) and lipid peroxidation (r = -0.8, P = 0.0006; r = -0.58, P = 0.01, respectively), GSH/(GSH + GSSG) ratio (r = -0.61, P = 0.05; r = -0.4, P = 0.14, respectively), GSH reductase (r = -0.75, P = 0.002; r = -0.53, P = 0.02, respectively), and GST activities (r = -0.65, P = 0.01; r = -0.44, P = 0.07, respectively). Similar correlation between foci number (no./cm(3)) and PGE(2), lipid peroxidation, GSH/(GSH + GSSG) ratio, GSH reductase, and GST activities were obtained. The results of this study show that dietary fish oil significantly inhibited hepatic enzyme-altered foci formation compared with corn oil in rats. These results suggest that the possible mechanisms involved in this process are the stimulation of hepatic detoxification system, changes in membrane composition, inhibition of PGE(2) synthesis, the enhancement of GSH-related antioxidant capacity, and the enhancement of lipid peroxidation by fish oil.

Changes in circulating levels of an anti-inflammatory cytokine interleukin 10 in burned patients

In order to understand the role of an anti-inflammatory cytokine interleukin 10 (IL-10) in the pathophysiology of burn injury, IL-10 levels in serial serum samples of 22 burned patients were analyzed. The total body surface areas (TBSA) of the burn injury ranged from 30 to 90%. Among these 22 patients, 14 recovered and the other eight, who were septic, expired. A significant difference in serum IL-10 values on admission (5-20 h postburn) was found (P<0.05) between patients who survived or died from burn injury as analyzed by the Student's t test. In addition, a significant difference in serum IL-10 on admission was also found (P<0.05) between patients with TBSA of greater or less than 50%. An initial peak serum IL-10 response was detected within 2.5 days postburn. Significant differences in the peak serum IL-10 levels were not found between patients with TBSA of greater or less than 50% and patients who survived or expired from burn injury. Afterwards, serum IL-10 remained low in the survivors, while an increase in serum IL-10 could be detected in the non-survivors with proven sepsis. Levels of circulating IL-6 in these non-surviving patients showed a tendency to increase starting from about 1-2 weeks postburn which coincided temporally with the detection of infections. However, marked increases in circulating IL-10 levels were observed just before death in four of the eight non-survivors. The serum samples of these four patients were collected at 31 h (404.8 pg/ml), 2 h (773.9 pg/ml), 5 days (150.7 pg/ml) and 12 h (177.1 pg/ml) before the expiration of these patients, respectively. IL-10 levels of 28.6, 27. 5 and 13.5 pg/ml were detected in sera of three of the remaining four non-survivors that were collected at 2.5 h, 36 h and 30 h before the expiration of these patients, respectively. There was one non-surviving patient who suffered an 80% burn (patient D4 in Table 1 and Fig. 4) and his IL-10 level at 20 days postburn was 13.4 pg/ml. The serum sample of this patient was collected 22 days before death and he was not suffering from sepsis at this stage. In conclusion, an initial increase in serum levels of IL-10 was detected postburn. A marked increase in serum levels of IL-10 was detected in four of the eight septic patients just before their death. It was considered that a lack and/or a delay in the increase of circulating IL-10 may play a significant role in the pathophysiology of sepsis in burned patients.

Down-regulation of osteoblastic cell differentiation by epidermal growth factor receptor

The role of epidermal growth factor receptors (EGF-R) in osteogenic cell differentiation was investigated using preosteoblastic MC3T3-E1 (MC3T3) cells and osteoblast-like ROS 17/2.8 (ROS) cells. When cultured in the presence of beta-glycerophosphate (GP) and ascorbic acid (AA), MC3T3 cells underwent spontaneous differentiation into osteoblasts which was confirmed as they expressed osteoblast markers such as alkaline phosphatase (ALP), bone sialoprotein (BSP) and osteocalcin (OC). Interestingly, the number of EGF-binding sites decreased during their differentiation into osteoblasts, and the osteogenic protein-1 (OP-1) treatment, which accelerated their differentiation, lowered the number of EGF-binding sites even further. On the other hand, ROS cells with high expression levels of osteoblast markers and no EGF-R, after being transfected with human EGF-R cDNA (EROS cells), expressed numerous EGF-binding sites as well as EGF-R mRNA and protein; in the process, they ceased to express osteoblast markers, indicating their dedifferentiation into osteoprogenitor cells. Both MC3T3 and EROS cells showed increased cell growth in response to EGF, whereas ROS cells did not. These results imply that the EGF/EGF-R system in osteogenic cells has a crucial function in osteoblast phenotype suppression and osteogenic cell proliferation.

Neurofibrillary tangles, amyotrophy and progressive motor disturbance in mice expressing mutant (P301L) tau protein

Neurofibrillary tangles (NFT) composed of the microtubule-associated protein tau are prominent in Alzheimer disease (AD), Pick disease, progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Mutations in the gene (Mtapt) encoding tau protein cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), thereby proving that tau dysfunction can directly result in neurodegeneration. Expression of human tau containing the most common FTDP-17 mutation (P301L) results in motor and behavioural deficits in transgenic mice, with age- and gene-dose-dependent development of NFT. This phenotype occurred as early as 6.5 months in hemizygous and 4.5 months in homozygous animals. NFT and Pick-body-like neuronal lesions occurred in the amygdala, septal nuclei, pre-optic nuclei, hypothalamus, midbrain, pons, medulla, deep cerebellar nuclei and spinal cord, with tau-immunoreactive pre-tangles in the cortex, hippocampus and basal ganglia. Areas with the most NFT had reactive gliosis. Spinal cord had axonal spheroids, anterior horn cell loss and axonal degeneration in anterior spinal roots. We also saw peripheral neuropathy and skeletal muscle with neurogenic atrophy. Brain and spinal cord contained insoluble tau that co-migrated with insoluble tau from AD and FTDP-17 brains. The phenotype of mice expressing P301L mutant tau mimics features of human tauopathies and provides a model for investigating the pathogenesis of diseases with NFT.

Induction of apoptosis by hibiscus protocatechuic acid in human leukemia cells via reduction of retinoblastoma (RB) phosphorylation and Bcl-2 expression

Hibiscus protocatechuic acid (PCA), a phenolic compound isolated from the dried flower of Hibiscus sabdariffa L. (Malvaceae), demonstrated antioxidant and antitumor promotion effects in our previous study. In the present study, Hibiscus PCA was found to inhibit the survival of human promyelocytic leukemia HL-60 cells in a concentration- and time-dependent manner. The study revealed that HL-60 cells underwent internucleosomal DNA fragmentation and morphological changes characteristic of apoptosis after a 9-hr treatment with Hibiscus PCA (2 mM). Flow cytometric analysis of the DNA content of cells treated with PCA for 12 hr showed that the cells were distributed mainly in the hypodiploid phase (apoptotic peak, 46.7%), less in the G(1) (34.2%) and S phase (14.0%), and few in the G(2)/M phase (5.1%). Moreover, PCA treatment caused an increase in the level of hypophosphorylated retinoblastoma (RB; 180% of control at the 6-hr time point) and, on the contrary, a decline in hyperphosphorylated RB. A rapid loss of RB was observed when the treatment period was extended. Further studies showed that Hibiscus PCA application reduced Bcl-2 protein expression to 47%, and increased Bax protein expression to 181% after 1.5 hr as compared with time 0. Overexpression of Bcl-2 in HL-60 cells delayed the occurrence of Hibiscus PCA-induced apoptosis. These data suggest that Hibiscus PCA is an apoptosis inducer in human leukemia cells, and that RB phosphorylation and Bcl-2 protein may play a crucial role in the early stage.

A qualitative and quantitative study of grumose degeneration in progressive supranuclear palsy

Grumose degeneration (GD) of the dentate nucleus is a common feature in progressive supranuclear palsy (PSP), but its pathogenesis has not been well studied, and its clinical significance remains unknown. This report describes a quantitative study of GD in 9 cases of PSP using image analysis with single- and double-immunolabeling, as well as histochemical stains for myelin and axons. GD was associated with demyelination, axonal loss, glial tau pathology, and microgliosis in regions juxtaposed to the dentate nucleus (DN). Specifically, demyelination and microgliosis were prominent in the superior cerebellar peduncle (SCP), dentate hilus, and cerebellar hemispheric white matter. Tau pathology and microgliosis were less prominent in the DN itself. The degree of myelin loss correlated with the tau burden in the SCP. GAP-43, which is a phosphoprotein known to be involved in axonal growth and sprouting, was decreased in the DN of PSP, and the degree of GAP-43 loss correlated with severity of GD. These results suggest that GD may be related to progressive pathology in the dentatorubrothalamic tract as well as the cerebellar hemispheric white matter, and that GD may be a consequence of concurrent degeneration in both output from and input to the DN. The results further suggest a possible role for oligodendroglial and myelin pathology in the pathogenesis of PSP.

Protective effect of Hibiscus anthocyanins against tert-butyl hydroperoxide-induced hepatic toxicity in rats

Hibiscus anthocyanins (HAs), a group of natural pigments occurring in the dried flowers of Hibiscus sabdariffa L., which is a local soft drink material and medical herb, were studied for antioxidant bioactivity. The preliminary study showed that HAs were able to quench the free radicals of 1,1-diphenyl-2-picrylhydrazyl. This antioxidant bioactivitiy was further evaluated using the model of tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity in rat primary hepatocytes and hepatotoxicity in rats. The results demonstrated that HAs, at the concentrations of 0.10 and 0.20 mg/ml, significantly decreased the leakage of lactate dehydrogenase and the formation of malondialdehyde induced by a 30-min treatment of t-BHP (1.5 mM). The in vivo investigation showed that the oral pretreatment of HAs (100 and 200 mg/kg) for 5 days before a single dose of t-BHP (0.2 mmol/kg, ip) significantly lowered the serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and reduced oxidative liver damage. The histopathological evaluation of the liver revealed that Hibiscus pigments reduced the incidence of liver lesions including inflammatory, leucocyte infiltration, and necrosis induced by t-BHP in rats. Based on the results described above, we speculate that Hibiscus pigments may play a role in the prevention of oxidative damage in living systems.

Theoretical study of temperature elevation at muscle/bone interface during ultrasound hyperthermia

This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperature distribution is based on the steady-state bio-heat transfer equation. The parameters considered are the incident angle of ultrasound beam, the ultrasound frequency, the acoustic attenuation coefficients of refracted longitudinal and shear waves in bone, and the blood perfusion in muscle. The results show that the peak of the SAR ratio is always at the interface of muscle and bone, while the peak of temperature is located in the bone region beyond the interface. A muscle with lower perfusion or a bone with higher acoustic attenuation results in the shifting of the temperature peak closer to the interface. It is more difficult to heat a higher perfused muscle in front of a bone using a lower frequency ultrasound since the temperature elevation for bone relative to muscle is greater.

Theoretical study of convergent ultrasound hyperthermia for treating bone tumors

This study investigates the optimal external parameters for using an ultrasound applicator for treating bone tumors. This system utilized spherically arranged applicators such as scanned focused ultrasound, and spherically focused multielement applicators. The power deposition pattern is modeled as geometric gain with exponential attenuation. The specific absorption rate ratio (SARR) criteria have been used to determine the proper heating domain of ultrasound driving frequency and therapeutic tumor diameter. The results demonstrate that the optimal driving frequency depends on tumor depth, ultrasound absorption of bone marrow, and diameter of bone, but it is independent of the acoustic window area and SARR. The treatable diameter of bone tumor increased when the absorption ratio of bone marrow to tumor, acoustic window of surface skin, and diameter of bone were elevated. However, the treatable diameter of bone tumor decreased when muscle thickness, SARR of bone tumor site to the surface skin, bone marrow, and bone declined. To deliver the ultrasound energy into the tumor site and to avoid the potential damage to the normal tissue as much as possible, the specific absorption rate (SAR) in the bone tumor site has to be three times higher than that in the surface skin, tumor/marrow, and marrow/bone interfaces. The temperature distributions can verify the SARR criteria in this model. This study provides the information for choosing the optimal operating frequency of the ultrasound transducer and the acoustic window on the skin surface, and for designing the ultrasound applicator for clinical implementation.

Complementary DNA cloning and immunologic characterization of a new Penicillium citrinum allergen (Pen c 3)

BACKGROUND

Penicillium citrinum has been identified as the most prevalent airborne Penicillium species in the Taipei area. It is important to understand the allergenic composition of this ubiquitous fungal species.

OBJECTIVE

The complementary DNA (cDNA) clone of an allergen from P citrinum was isolated and expressed in Escherichia coli as a fusion protein. mAbs were prepared with the recombinant protein as antigen. The corresponding natural allergen in the fungal extracts was identified with the mAbs.

METHODS

A Uni-Zap XR P citrinum cDNA library was screened with sera from asthmatic patients. An IgE-binding cDNA clone was isolated and expressed as a glutathione-S-transferase fusion protein. The frequency of IgE binding to the expressed protein was analyzed by immunoblotting. Spleen cells from BALB/c mice immunized with the recombinant protein were fused with NS-1 cells for mAb generation.

RESULTS

A P citrinum cDNA library was screened with a mixture of serum samples from 4 asthmatic patients. An IgE-binding cDNA clone was obtained and designated as PCE2. PCE2 has a 694-bp insert that contains a 167 amino acids open reading frame. The deduced amino acid sequence of the encoded protein has 82.6% (138 amino acids) identity with an Aspergillus fumigatus peroxisomal membrane protein allergen (Asp f 3). PCE2 was expressed in E coli as a fusion protein and designated as Pen c 3. Sera from 13 (46%) of the 28 Penicillium-sensitized asthmatic patients demonstrated IgE binding to Pen c 3. In addition, 11 of the 13 Pen c 3-positive serum samples have IgE immunoblot reactivity to recombinant Asp f 3. The presence of IgE cross-reactivity between Pen c 3 and Asp f 3 was also detected by immunoblot inhibition. Four of the 6 mAbs generated against Pen c 3 cross-react with Asp f 3. The presence of the corresponding 18-k natural allergens in the crude extracts of P citrinum and A fumigatus were detected by immunoblot with use of the mAbs and sera from asthmatic patients.

CONCLUSION

Results obtained suggest that the peroxisomal membrane protein (Pen c 3) is an important allergen of P citrinum. PCE2 is a full-length cDNA clone encoding this allergen. In addition, the mAbs generated may be useful in standardizing the diagnostic allergenic extracts.

A theoretical study of cylindrical ultrasound transducers for intracavitary hyperthermia

PURPOSE

The purpose of this paper was to examine the heating patterns and penetration depth when a cylindrical ultrasound transducer is employed for intracavitary hyperthermia treatments.

METHODS AND MATERIALS

The present study employs a simulation program based on a simplified power deposition model for infinitely long cylindrical ultrasound transducers. The ultrasound power in the tissue is assumed to be exponentially attenuated according to the penetration depth of the ultrasound beam, and a uniform attenuation for the entire treatment region is also assumed. The distribution of specific absorption rate (SAR) ratio (the ratio of SAR for a point within the tissue to that for a specific point on the cavity surface) is used to determine the heating pattern for a set of given parameters. The parameters considered are the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity.

RESULTS

Simulation results show that the ultrasound attenuation in the tissue, the cavity size, and the transducer eccentricity are the most influential parameters for the distribution of SAR ratio. A low frequency transducer located in a large cavity can produce a much better penetration. The cavity size is the major parameter affecting the penetration depth for a small cavity size, such as interstitial hyperthermia. The heating pattern can also be dramatically changed by the transducer eccentricity and radiating sector. In addition, for a finite length of cylindrical transducer, lower SAR ratio appears in the regions near the applicator's edges.

CONCLUSION

The distribution of SAR ratio indicates the relationship between the treatable region and the parameters if an appropriate threshold of SAR ratio is taken. The findings of the present study comprehend whether or not a tumor is treatable, as well as select the optimal driving frequency, the appropriate cavity size, and the eccentricity of a cylindrical transducer for a specific treatment.

Treatable domain and optimal frequency for brain tumors during ultrasound hyperthermia

PURPOSE

To examine the optimal ultrasound frequency and the treatable domain determined by the tumor size and tumor depth when an external ultrasound heating system is employed for the brain tumor hyperthermia.

METHODS AND MATERIALS

This work employs a simplified model of a scanned ultrasound transducer power deposition (a cone with convergent/divergent shape) and a search algorithm to investigate the optimal frequency and the treatable domain. The distributions of temperature and SAR (specific absorption rate) ratio are used to determine the appropriateness of the acoustic window size and the input power level for a yielded set of tumor conditions. The factors considered are the acoustic window size, tumor size and depth, ultrasound frequency, and the acoustic absorption of the post-target bone behind the tumor.

RESULTS

Simulation results demonstrate that the optimal frequency depends on the tumor depth and the acoustic absorption of the post-target bone. However, it is almost independent of the acoustic window size. The optimal frequency shifts to a higher level for a deeper tumor heating to reduce the effect of the high acoustic absorption of post-target bone. Moreover, the treatable domain is proportional to the acoustic window size and related to the ultrasound frequency.

CONCLUSION

It may not be possible to deliver appropriate ultrasonic energy to heat a brain tumor without overheating the normal brain tissue and/or the post-target bone under the constraints of the available acoustic window size for the ultrasonic beam, ultrasonic attenuation of brain tissue, high absorption of post-target bone, and high blood perfusion rate. The results of this study can be a guideline for designing an optimal ultrasound heating system, arranging the transducers, and implementing further treatment planning for the brain tumor hyperthermia.

Inhibitory effect of 12-O-tetradecanoylphorbol-13-acetate-caused tumor promotion in benzo[a]pyrene-initiated CD-1 mouse skin by baicalein

The effects of topical application of baicalein on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced promotion of skin tumors, hyperplasia, ornithine decarboxylase activity, and inflammation were evaluated in female CD-1 mice. Topical application of baicalein (0.08, 0.16, or 0.2 mumol) with TPA (5 nmol) twice weekly for 24 weeks to mice previously initiated with benzo[a]pyrene inhibited the number of TPA-induced tumors per mouse significantly. Preapplication of the same amount of baicalein also afforded significant protection against TPA-induced hyperplasia in the ear skin. Topical application of baicalein inhibited tumor promoter-caused induction of epidermal ornithine decarboxylase activity by TPA (5 nmol). The topical application of baicalein (0.008, 0.016, or 0.02 mumol) inhibited TPA-induced edema of mouse ears by 88%, 96%, or 97%, respectively. Pretreatment of mouse skin with various amounts of baicalein caused inhibition of H2O2 and myeloperoxidase formation by TPA. These results indicate that baicalein can be a potential cancer-chemopreventive agent against tumor promotion.

Optimal configuration of multiple-focused ultrasound transducers for external hyperthermia

External ultrasound hyperthermia is considered to be a very flexible modality for heating deep-seated tumors owing to its penetration and focusing ability. However, using this flexibility requires that many complicated, interacting decisions be made to obtain optimal treatment. This paper presents the feasibility of arranging multiple-focused ultrasound transducers to produce an appropriate heating pattern for a specific treatment, based on the optimal scan parameters obtained from an optimization algorithm. The variable scan parameters of the heating system optimized are the transducer tilt and rotation angles, focal depth, scan radius, and output acoustical power. After obtaining the optimal scan parameters, multiple transducers are systematically arranged according to these scan parameters. Three-dimensional ultrasound power deposition and temperature distribution for a specific treatment are calculated for this multiple ultrasound transducer system. A more uniform temperature distribution in the treatment region for a large, highly perfused tumor can be achieved by scanning the system with respect to the central scan axis and/or swinging the transducers inwards and outwards. The maximum heating depth of focused ultrasound transducers used in this heating system is also studied. Simulation results demonstrate that the optimal arrangement of this multiple-focused ultrasound transducer system is highly promising for heating deep, large, and highly perfused tumors.

N-cadherin expression during periodontal ligament cell differentiation in vitro

BACKGROUND

When confluent periodontal ligament (PDL) cells were cultured in the presence of dexamethasone (Dex), ascorbic acid (AA), and beta-glycerophosphate (GP), they underwent sequential differentiation, demonstrating distinct morphological characteristics. At 1 week, localized cell proliferation led to the formation of multilayers of cells. As cell differentiation progressed, they formed nodules by deposition of matrix in the clusters of cells at 2 weeks, and mineralized the nodules at 3 weeks. These changes implicate extensive cell-to-cell interactions. Cadherins are known to play an important role in establishing cell contacts during tissue formation.

METHODS

To determine whether cadherins are involved in PDL cell differentiation, and the formation and mineralization of nodules by the cells in vitro, we investigated the expression of N-cadherin using immunofluorescence labeling and Northern blot analysis.

RESULTS

Immunolabeling showed that N-cadherin was expressed in PDL cells in the stages of nodule formation and mineralization. Northern blot analysis demonstrated a 3-fold increase in the expression of N-cadherin mRNA in the stages. However, neither E-cadherin nor P-cadherin was expressed.

CONCLUSIONS

Our data suggest that N-cadherin may play an important role in PDL cell differentiation and the formation of mineralized nodules by PDL cells.

Alkaline serine proteinase is a major allergen of Aspergillus flavus, a prevalent airborne Aspergillus species in the Taipei area

BACKGROUND

Aspergillus species are prevalent indoor airborne fungi and have been identified to be a causative agent of human allergic disorders. In the present study, we identified, purified and characterized the allergen(s) from Aspergillus flavus, a predominant airborne Aspergillus species in the Taipei area.

METHODS

The IgE-binding components of A. flavus were identified by SDS-PAGE immunoblotting with sera from asthmatic patients. The N-terminal amino acid sequences of the major allergens were determined by Edman degradation. The allergenic cross-reactivity among allergens from different fungi was analyzed by immunoblot inhibition using sera from asthmatic patients. The detected major allergen was purified from the culture medium. It was further characterized in terms of its N-terminal amino acid sequence, its IgE-binding activity and its enzymatic activity.

RESULTS

The results of the immunoblot analysis indicate that a 34-kD component that has high IgE-binding (63%) frequency is a major allergen of A. flavus. The N-terminus of this 34-kD major allergen (GLTTQKSAP) has high sequence identity with that of the 34-kD alkaline serine proteinase major allergen of A. oryzae. Results from immunoblot inhibition studies indicate that IgE cross-reactivity occurs among the 34-kD major allergens of A. flavus, A. fumigatus and Penicillium citrinum. The 34-kD major allergen of A. flavus was purified from the culture medium by ammonium sulfate precipitation and DEAE ion exchange chromatography. The N-terminal amino acid sequence of the purified allergen (Asp fl 13) is identical to that determined previously for the 34-kD major allergen in the crude extract of A. flavus. The IgE immunoblot reactivity to the 34-kD major allergen in the crude extract can be dose-dependently inhibited by the purified Asp fl 13. The degree of IgE binding to the 34-kD major allergen in the crude extract correlates with that of the purified Asp fl 13 in sera of 8 asthmatic patients. The purified Asp fl 13 has proteolytic activity with casein as substrate at pH 8.0. This enzymatic activity can be inhibited by either phenylmethylsulfonyl fluoride or diethylpyrocarbonate.

CONCLUSION

Our results suggest that the 34-kD alkaline serine proteinase is a major allergen of A. flavus. There was IgE cross-reactivity among allergens of A. flavus, A. fumigatus and P. citrinum.

Expression of TGF-beta isoforms and their receptors during mineralized nodule formation by rat periodontal ligament cells in vitro

Transforming growth factor-betas (TGF-beta s) and bone morphogenetic proteins (BMPs), members of a TGF-beta superfamily, are known to play an important role in osteogenic cell differentiation and consequently bone formation. We have reported previously that periodontal ligament (PDL) cells differentiate and form mineralized nodules when cultured in the presence of dexamethasone (Dex), beta-glycerophosphate (GP) and ascorbic acid (AA). To understand the roles of TGF-beta isoforms (TGF-beta 1, 2 and 3) and TGF-beta type I receptors (activin receptor-like kinase (ALK)-2, -3, -5 and -6) in PDL cell differentiation, their expression was investigated using Northern blot analysis. Rat PDL cells, derived from coagulum in the tooth socket, were cultured in the presence of Dex (5 microM), GP (10 mM) and AA (50 micrograms/ml) for up to 21 d. Total RNA was isolated from PDL cells after 0, 7, 14 and 21 d and used for northern blot analysis of mRNAs for matrix proteins, TGF-beta isoforms and their receptors using 32P-labeled cDNAs as probes. Four stages showing distinct morphological characteristics and matrix expression during development of mineralized nodules were identified. Type I collagen (Col I) and SPARC (secreted protein, acidic and rich in cysteine) mRNAs were expressed at the confluent stage, but decreased during the mineralization stage. Osteopontin (OPN) and alkaline phosphatase (ALP) transcripts were initially observed at multilayer stage, while bone sialoprotein (BSP) and osteocalcin (OC) at the nodule stage and all 4 were expressed thereafter. TGF-beta 1 mRNA expression increased with the progression of PDL cell differentiation, while a relatively high level of TGF-beta 3 transcript decreased slightly during their differentiation. TGF-beta 2 mRNA was not expressed. The expression of TGF beta-RI mRNA decreased, whereas that of TGF beta-RIII increased dramatically with PDL cell differentiation. TGF beta-RII gene activities remained high throughout all stages. ALK-2, ALK-3 and ALK-6 mRNA expression increased with the progression of PDL cell differentiation, suggesting that these receptors may play important roles in Dex-induced PDL cell differentiation and mineralized nodule formation.

Melatonin promotes osteoblast differentiation and bone formation

Prior studies have demonstrated that the pineal hormone, melatonin, can stimulate chloramphenicol acetyltransferase activity in Drosophila SL-3 cells transfected with a chloramphenicol acetyltransferase reporter construct containing the response element of rat bone sialoprotein (BSP). Based on these findings, studies were performed to determine whether melatonin could similarly modulate the expression of BSP in two cell lines, the MC3T3-E1(MC3T3) pre-osteoblast and rat osteoblast-like osteosarcoma 17/2.8 cell. Initial studies demonstrated that MC3T3 cells grown in the presence of 50 nM melatonin underwent cell differentiation and mineralization by day 12 instead of the 21-day period normally required for cells grown in untreated media. Melatonin increased gene expression of BSP and the other bone marker proteins, including alkaline phosphatase (ALP); osteopontin; secreted protein, acidic and rich in cysteine; and osteocalcin in MC3T3 cells in a concentration-dependent manner. Levels of melatonin as low as 10 nM were capable of stimulating transcription of these genes when cells were grown in the presence of beta-glycerophosphate and ascorbic acid. Under these conditions, melatonin induced gene expression of the bone marker proteins; however, this does not occur until the 5th day after seeding the culture dishes. Thereafter, MC3T3 cells responded to melatonin within 2 h of treatment. The fully differentiated rat osteoblast-like osteosarcoma 17/2.8 cells responded rapidly to melatonin and displayed an increase in the expression of BSP, ALP, and osteocalcin genes within 1 h of exposure to the hormone. To determine whether melatonin-induced osteoblast differentiation and bone formation are mediated via the transmembrane receptor, MC3T3 cells were treated in the presence and absence of melatonin with either luzindole, a competitive inhibitor of the binding of melatonin to the transmembrane receptors, or pertussis toxin, an uncoupler of G(i) from adenylate cyclase. Both luzindole and pertussis toxin were shown to reduce melatonin-induced expression of BSP and ALP. These results demonstrate, for the first time, that the pineal hormone, melatonin, is capable of promoting osteoblast differentiation and mineralization of matrix in culture and suggest that this hormone may play an essential role in regulating bone growth.

Relationship between acoustic aperture size and tumor conditions for external ultrasound hyperthermia

External ultrasound hyperthermia is a very flexible modality for heating deep-seated tumors due to its deep penetration and focusing ability. However, under the constraints of the available acoustic aperture size for the ultrasonic beam, ultrasonic attenuation, as well as other anatomic properties, it may not be able to deliver sufficient ultrasonic energy to heat a large tumor located in a deep region without overheating the normal tissue between the tumor and the aperture. In this work, we employ a simulation program based on the steady-state bioheat transfer equation and an ideal ultrasound power deposition (a cone with convergent/divergent shape) to examine the relationship between the minimal diameter of the acoustic aperture and the tumor conditions. Tissue temperatures are used to determine the appropriate aperture diameter and the input power level for a given set of tumor conditions. Due to the assumed central axis symmetry of the power intensity deposition and anatomic properties, a two-dimensional (r-z) simulation program is utilized. Factors determining the acoustic aperture diameter and the input power level considered here are the tumor size, tumor depth, ultrasonic attenuation in tissue, blood perfusion, and temperature of the surface cooling water. Simulation results demonstrate that tumor size, tumor depth, and ultrasonic attenuation are major factors affecting the aperture diameter of the ultrasonic beam to obtain an appropriate temperature distribution, while blood perfusion and the temperature of the surface cooling water are the minor factors. Plots of the effects of these factors can be used as the guideline for designing an optimal ultrasound heating system, arranging the transducers, and planning further treatments.