[A giant malignant melanoma of the palpebral conjunctiva: a case report]

An 81-year-old female patient experienced a rapid increase in the volume of a rice-sized black mass on the left eye over a period of six months. The mass extended out of the eye and exhibited surface erosion with accompanying hemorrhage. Following a live tissue examination and histopathology after orbital exenteration under general anesthesia, the diagnosis of a giant malignant palpebral conjunctival melanoma of the spindle cell subtype was confirmed. The patient refused to undergo local radiation therapy or systemic chemotherapy and died from the disease six months later.

[Exploration of making removable partial denture by digital technology]

To explore the digital manufacturing process of distal extension removable partial denture. From November 2021 to December 2022, 12 patients (7 males and 5 females) with free-ending situation were selected from the Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University. Three-dimensional model of the relationship between alveolar ridge and jaw position was obtained by intraoral scanning technique. After routine design, manufacturing and try-in of metal framework for removable partial denture, the metal framework was located in the mouth and scanned again to obtain the composite model of dentition, alveolar ridge and metal framework. The free-end modified model is obtained by merging the digital model of free-end alveolar ridge with the virtual model with the metal framework. The three-dimensional model of artificial dentition, and base plate was designed on the free-end modified model, and the resin model were made by digital milling technology. The removable partial denture was made by accurately positioning the artificial dentition and base plate, bonding metal framework with injection resin, grinding and polishing the artificial dentition and resin base. Compared with the design data after clinical trial, the results showed that there was an error of 0.4-1.0 mm and an error of 0.03-0.10 mm in the connection between the resin base of artificial dentition and the connecting rod of the in-place bolt and the connection between artificial dentition and resin base. After denturen delivery, only 2 patients needed grinding adjustment in follow-up visit due to tenderness, and the rest patients did not find any discomfort. The digital fabrication process of removable partial denture used in this study can basically solve the problems of digital fabrication of free-end modified model and assembly of artificial dentition with resin base and metal framework.

[Analysis on migration of HIV/AIDS cases and related factors in Liangshan Yi Autonomous Prefecture in Sichuan province, 2020]

Objective: To analyze the migration of the HIV/AIDS cases and related factors in Liangshan Yi autonomous prefecture (Liangshan). Methods: According to HIV/AIDS Comprehensive Response Information Management System of China Information System for Disease Control and Prevention, a total of 28 772 HIV/AIDS cases who had follow-up records in Liangshan in 2020 were included in the survey. The migration of the HIV/AIDS cases was described and the related factors were analyzed using multiple logistic regression models, and the migration destinations of the HIV/AIDS cases were mapped. Results: Among the 28 772 HIV/AIDS cases, 20.89% (6 010/28 772) had migration in 2020. Multivariate logistic regression analysis showed that among the HIV/AIDS cases, the migration related factors included being aged 15-24 years (compared with being aged 0-14 years, OR=2.74, 95%CI:2.04-3.69) and ethnic group (compared with Han ethnic group, OR=2.44, 95%CI:2.19-2.72), having education level of junior high school (compared with having education level of primary school or below, OR=1.25, 95%CI:1.14-1.38), being unmarried (compared with being married, OR=1.29, 95%CI:1.20-1.39), being engaged in business services (compared with being engaged in farming, OR=1.96, 95%CI:1.31-2.92), receiving antiviral treatment <1 year (compared with receiving antiviral treatment >3 years, OR=1.42, 95%CI:1.26-1.61), having recent CD4⁺T lymphocytes (CD4) counts >500 cells/μl (compared with having recent CD4 counts <200 cells/μl, OR=1.15, 95%CI:1.03-1.29). The geographical distribution maps showed that among all cities in Sichuan, Xichang (13.26%, 797/6 010) and Chengdu (10.12%,608/6 010) were the main migration destinations of the HIV/AIDS cases, and the provinces outside Sichuan where the HIV/AIDS cases would like to migrate to were mainly Guangdong (18.19%, 1 093/6 010) and Zhejiang provinces (7.67%, 461/6 010) in 2020. The HIV/AIDS cases who migrated where Liangshan, within Sichuan province, and to other provinces accounted for 27.67% (1 663/6 010), 15.34% (922/6 010) and 56.99% (3 425/6 010), respectively. Conclusions: More attention should be paid to the mobility characteristics and the classification management of HIV/AIDS cases according to their characteristics in Liangshan. Timely access to information on changes in the place of work and residence of HIV/AIDS cases should be warranted when they have migration. Good referrals and management for mobility of HIV/AIDS cases in different places should be made to reduce loss to follow-up and improving interventions.

2-Hexyl-4-Pentylenic Acid (HPTA) Stimulates the Radiotherapy-induced Abscopal Effect on Distal Tumor through Polarization of Tumor-associated Macrophages

OBJECTIVE

The aim of this study was to explore the effects of 2-hexyl-4-pentylenic acid (HPTA) in combination with radiotherapy (RT) on distant unirradiated breast tumors.

METHODS

Using a rat model of chemical carcinogen (7,12-dimethylbenz[a]anthracene,DMBA)-induced breast cancer, tumor volume was monitored and treatment response was evaluated by performing HE staining, immunohistochemistry, immunofluorescence, qRT-PCR, and western blot analyses.

RESULTS

The results demonstrated that HPTA in combination with RT significantly delayed the growth of distant, unirradiated breast tumors. The mechanism of action included tumor-associated macrophage (TAM) infiltration into distant tumor tissues, M1 polarization, and inhibition of tumor angiogenesis by IFN-γ.

CONCLUSION

The results suggest that the combination of HPTA with RT has an abscopal effect on distant tumors via M1-polarized TAMs, and HPTA may be considered as a new therapeutic for amplifying the efficacy of local RT for non-targeted breast tumors.

The graphical abstract was available in the web of www.besjournal.com.

Influence of Surface Passivation on AlN Barrier Stress and Scattering Mechanism in Ultra-thin AlN/GaN Heterostructure Field-Effect Transistors

Ultra-thin AlN/GaN heterostructure field-effect transistors (HFETs) with, and without, SiN passivation were fabricated by the same growth and device processes. Based on the measured DC characteristics, including the capacitance-voltage (C-V) and output current-voltage (I-V) curves, the variation of electron mobility with gate bias was found to be quite different for devices with, and without, SiN passivation. Although the AlN barrier layer is ultra thin (c. 3 nm), it was proved that SiN passivation induces no additional tensile stress and has no significant influence on the piezoelectric polarization of the AlN layer using Hall and Raman measurements. The SiN passivation was found to affect the surface properties, thereby increasing the electron density of the two-dimensional electron gas (2DEG) under the access region. The higher electron density in the access region after SiN passivation enhanced the electrostatic screening for the non-uniform distributed polarization charges, meaning that the polarization Coulomb field scattering has a weaker effect on the electron drift mobility in AlN/GaN-based devices.

First Report of Pepper Fruit Rot Caused by Fusarium concentricum in China

Pepper (Capsicum annuum L.) is an important vegetable crop worldwide. Some Fusarium species can cause pepper fruit rot, leading to significant yield losses of pepper production and, for some Fusarium species, potential risk of mycotoxin contamination. A total of 106 diseased pepper fruit samples were collected from various pepper cultivars from seven provinces (Gansu, Hainan, Heilongjiang, Hunan, Shandong, Shanghai, and Zhejiang) in China during the 2012 growing season, where pepper production occurs on approximately 25,000 ha. Pepper fruit rot symptom incidence ranged from 5 to 20% in individual fields. Symptomatic fruit tissue was surface-sterilized in 0.1% HgCl₂ for 1 min, dipped in 70% ethanol for 30 s, then rinsed in sterilized distilled water three times, dried, and plated in 90 mm diameter petri dishes containing potato dextrose agar (PDA). After incubation for 5 days at 28°C in the dark, putative Fusarium colonies were purified by single-sporing. Forty-three Fusarium strains were isolated and identified to species as described previously (1,2). Morphological characteristics of one strain were identical to those of F. concentricum. Aerial mycelium was reddish-white with an average growth rate of 4.2 to 4.3 mm/day at 25°C in the dark on PDA. Pigments in the agar were formed in alternating red and orange concentric rings. Microconidia were 0- to 1-septate, mostly 0-septate, and oval, obovoid to allantoid. Macroconidia were relatively slender with no significant curvature, 3- to 5-septate, with a beaked apical cell and a foot-shaped basal cell. To confirm the species identity, the partial TEF gene sequence (646 bp) was amplified and sequenced (GenBank Accession No. KC816735). A BLASTn search with TEF gene sequences in NCBI and the Fusarium ID databases revealed 99.7 and 100% sequence identity, respectively, to known TEF sequences of F. concentricum. Thus, both morphological and molecular criteria supported identification of the strain as F. concentricum. This strain was deposited as Accession MUCL 54697 (http://bccm.belspo.be/about/mucl.php). Pathogenicity of the strain was confirmed by inoculating 10 wounded, mature pepper fruits that had been harvested 70 days after planting the cultivar Zhongjiao-5 with a conidial suspension (1 × 10⁶ spores/ml), as described previously (3). A control treatment consisted of inoculating 10 pepper fruits of the same cultivar with sterilized distilled water. The fruit were incubated at 25°C in a moist chamber, and the experiment was repeated independently in triplicate. Initially, green to dark brown lesions were observed on the outer surface of inoculated fruit. Typical soft-rot symptoms and lesions were observed on the inner wall when the fruit were cut open 10 days post-inoculation. Some infected seeds in the fruits were grayish-black and covered by mycelium, similar to the original fruit symptoms observed at the sampling sites. The control fruit remained healthy after 10 days of incubation. The same fungus was isolated from the inoculated infected fruit using the method described above, but no fungal growth was observed from the control fruit. To our knowledge, this is the first report of F. concentricum causing a pepper fruit rot. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (2) K. O'Donnell et al. Proc. Nat. Acad. Sci. USA 95:2044, 1998. (3) Y. Yang et al. 2011. Int. J. Food Microbiol. 151:150, 2011.

An impact rotary motor based on a fiber torsional piezoelectric actuator

A prototype small impact rotary motor has been fabricated based on a newly developed torsional actuator which is 15.0 mm long and 1.0 mm in diameter. The motor can rotate when it is powered with a saw-shaped voltage. The experimental results show that its angular speed is proportional to both the driving voltage's amplitude and the frequency under 1 kHz. The large nonlinearity occurs at higher driving frequency due to the resonance of the partial mechanical structure of the motor. The motor can rotate at a speed of 90 rpm with a saw-shaped driving voltage of 600 V(p.-p.) at 8 kHz, and produce a stall torque of 80 microN m with 1000 V(p.-p.) at 3 kHz.

Disinfection of maxillofacial silicone elastomer using a novel antimicrobial agent: recombinant human beta-defensin-3

Maxillofacial silicone elastomer, when used as a prosthesis, is in contact with wound surfaces and mucosa, and tends to be contaminated with microorganisms from a patient's saliva and blood. The aim of the study was to evaluate the efficacy of human beta-defensin-3 (HBD3) on the reduction of two resistant bacteria species from the surface of maxillofacial silicone elastomer. HBD3 cDNA was amplified from total RNA, which had been extracted from human gingival epithelium by means of reverse-transcription polymerase chain reaction (RT-PCR). Following this, the cDNA fragments were recombined in a prokaryotic expression vector. The constructed expression vectors pET-32a/HBD3 were transformed into Escherichia coli to obtain recombinant protein. After protein purification and refolding, the product was verified in classic antimicrobial experiments against Staphylococcus aureus and Candida albicans. Specimens made of silicone elastomer A-2186, which had been contaminated with S. aureus or C. albicans, were immersed in rHBD3 or 5.25% sodium hypochlorite (a positive control) for 5 min, 10 min, 30 min, or 60 min. The active recombinant HBD3 obtained in the current study eliminated the S. aureus and C. albicans microorganism from the surface of the maxillofacial elastomer after a 30-min immersion. There was no statistically significant difference between the rHBD3 group and the sodium hypochlorite 5.25% group. In conclusion, rHBD3 exhibits antibacterial activity against oral pathogenic strains that adhere to maxillofacial elastomer, and may, thus, contribute to the prevention of infections caused by S. aureus and C. albicans.

TLR signaling by tumor and immune cells: a double-edged sword

The tumor cell signaling pathways that trigger the uncontrolled proliferation, resistance to apoptosis, metastasis and escape from immune surveillance are partially understood. Toll-like receptors (TLRs), which recognize a variety of pathogen-associated molecular patterns, are centrally involved in the initiation of the innate and adaptive immune responses. However, recent evidence shows that functional TLRs are also expressed on a wide variety of tumors suggesting that TLRs may play important roles in tumor biology. Activation of tumor cell TLRs not only promotes tumor cell proliferation and resistance to apoptosis, but also enhances tumor cell invasion and metastasis by regulating metalloproteinases and integrins. Moreover, the activation of TLR signaling in tumor cells induces the synthesis of proinflammatory factors and immunosuppressive molecules, which enhance the resistance of tumor cells to cytotoxic lymphocyte attack and lead to immune evasion. Thus, the neoplastic process may usurp TLR signaling pathways to advance cancer progression, which suggests that targeting tumor TLR signaling pathways may open novel therapeutic avenues.

The influence of preamplifiers on the piezoelectric sensor's dynamic property

A charge amplifier or a voltage amplifier can be used as a signal conditioning circuit between a piezoelectric element and a meter or a data acquisition board. The outputs of the piezoelectric sensor are in an open-circuit state and a short-circuit state if a voltage amplifier and a charge amplifier are used, respectively. When the electrodes are in different states, the piezoelectric element has rather different stiffness and thus different sensor resonant frequency. This phenomenon is theoretically analyzed in detail and validated by a carefully designed experiment. The results indicate that a much wider range of working frequency is achieved when a voltage amplifier is used.

[Construction of expression plasmids harbouring genes encoding recombinant FN polypeptides with triple-domain and preliminary characterization of the products expressed in Escherichia coli]

To investigate the important role of recombinant triple-domain FN polypeptide in tumor therapy, two expression plasmids pF94-62 and pF94-82 were constructed and used to express triple-domain polypeptides of human FN in E. coli. The expressed polypeptides were CH62 (Pro 1239-Ser 1515 of FN linked with Ala 1690-Val 2049 through Met) and CH82 (CH62 without Pro 1953-Glu 1978). CH82 polypeptide was expressed as inclusion bodies in E. coli cultured at 37 degrees C. After denaturation with 8 mol/L urea and renaturation, the polypeptides were purified by the affinity chromatograph with Heparin-agarose, and the purified product was analysed by cell adhesion assay. The expression level of CH62 in E. coli was very low(5%), but that of CH82 was very high (21%), it suggested that N terminal sequence of Cell II in FN was the key sequence which influence the expression of triple-domain polypeptide in E. coli. The purified product was capable of binding heparin and cells, and it had a better binding activity than bifunctional-domain FN polypeptides. The production of CH82 polypeptide provided a fundamental basis for further study of recombinant product with better function of anti-metastasis and immune regulation.

Comparison of effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides

AIM

To investigate the characterization of pharmacological action & of CH50, a recombinant polypeptide of human fibronectin, by comparing the effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides (LPS).

METHODS

The production of nitric oxide (NO) as an index macrophage activation was determined by colorimetric assay. The interferon-gamma (IFN-gamma) transfection was performed with coprecipitation of calcium phosphate and DNA. The melanoma B16 cells were inoculated into abdominal cavity of mice and the number of tumor nodes was recorded.

RESULTS

At lower concentrations or when given alone in vitro, CH50 produced ten times less NO than LPS (P < 0.01). But at concentrations higher than 1 mg.L-1, CH50 activated the IFN-gamma-primed macrophages to produce NO to the same extent as LPS (P > 0.05). There was no synergism between CH50 and LPS. Both CH50 and LPS alone could reduce the number of tumor nodes in abdominal cavity of mice but CH50 had a stronger inhibitory effect on the growth of tumor in vivo as compared to LPS (P < 0.01). CH50/IFN-gamma had also a better inhibitory effect on tumor growth in vivo than LPS/IFN-gamma did.

CONCLUSION

In the presence of IFN-gamma, the ability of CH50 to activate macrophages is the same as that of LPS. But CH50 has better antitumorogenic effects in vivo against mouse melanoma as compared to LPS.

Effect of recombinant human fibronectin polypeptide CH50 on growth and metastasis of melanoma

AIM

To study the effect of recombinant human fibronectin polypeptide CH50 on murine melanoma growth and metastasis, and its antitumor mechanism.

METHODS

Mouse and melanoma B16 cell tests were used to observe antitumor effect and mechanism of CH50.

RESULTS

CH50 markedly inhibited melanoma growth and experimental lung metastasis. The melanoma weight was reduced from (2.3 +/- 1.2) g of control group to (0.7 +/- 0.8) g of test group (P < 0.05). CH50 at 0.125, 0.25, 0.5 mg/mouse reduced melanoma lung metastatic colonies from 87 +/- 49 of control group to 34 +/- 6, 14 +/- 12, 4 +/- 2, respectively. CH50 adhered to melanoma B16 cells and inhibited adhesion of B16 cells to laminin. CH50 enhanced the cytotoxicity of macrophages to melanoma B16 cells.

CONCLUSION

CH50 inhibited tumor growth and metastasis of murine melanoma. The antitumor effect of CH50 is related to its adhesion ability to melanoma B16 cells and enhancing macrophage cytotoxicity.

[Relationship between oxysterols and atherosclerosis]

Oxysterols, being oxygenated derivatives of cholesterol, are as many kinds as one hundred. They are found in the foodstuffs, the blood and arterial tissues of animals with hypercholesterolemia, the human atheroma, the foam cell from atherosclerotic tissues, as well as in the oxidized low density lipoprotein. The results of experiments have demonstrated that oxysterols are cytotoxic and they are injurious to a variety of cells including vascular endothelial cells, smooth muscle cells and monocyte/macrophages, suggesting that oxysterols could play a key role in the initiation and pathogenesis of atherosclerosis.

[Effect of silymarin on mouse liver damage, production and activity of tumor necrosis factor]

Tumor necrosis factor (TNF) has been well-characterized as a prominent mediator in the development of liver injury. Effects of silymarin (SB) on mouse liver damage, TNF production and activity were studied. Pretreatment with SB (25-50 mg.kg-1, i.p., bid x 3 d) before the lipopolysaccharides (LPS) injection markedly alleviated liver injury and diminished LPS-induced TNF production in Propionibacterium acnes (PA)-primed mice. SB (12.5-50 micrograms.ml-1) significantly inhibited LPS-induced TNF release from mouse peritoneal macrophage in a concentration-dependent manner. SB(12.5-100 micrograms.ml-1) was also shown to markedly reduce TNF cytotoxicity on human hepatic cell line GSG-7701 and mouse fibroblastic cell line L929 cells concentration-dependently. These results suggest that inhibition of TNF production and its actions may be involved in the mechanism of protective action of SB on liver damage.

[Mismatch repair in MNNG-induced genetically unstable monkey kidney vero cell]

Gel retardation analysis and in vitro DNA mismatch repair system were used to examine whether there were mismatch repair deficiency in MNNG-induced genetically unstable vero cell, which was manifested by a delayed and highly increased rate of non-targeted mutation. A mismatch binding protein which could selectively bind to G.T mispair in DNA was identified in its whole-cell extracts. It was also identified that G.T mispair could be specifically and effectively corrected into G.C pair in its nuclear extracts. Compared with normal vero cell, there were no functional deficiency of the above mismatch repair mechanisms. So it could be excluded the possibility that the functional deficiency of mismatch binding protein or G.T mismatch repair pathway participated in the induction of genetic instability in vero cell by MNNG.

The changes of AP-1 DNA binding activity and components in hippocampus of seizure-sensitive rat induced by kainate

Seizure-sensitive Fisher 344 rats were prepared 7 d after seizure episodes induced by a single subcutaneous administration of convulsive dose (7.5 mg/kg) of kainic acid. The activator protein-1 (AP-1) DNA binding activity and its components in the hippocampus of such rats were examined by Gel shift, Super-shift and Western blot assay. Gel shift assay showed that the basal level of AP-1 DNA binding activity was significantly higher than that of control rat hippocampus. Super-shift showed that only Fra and Jun D antibodies could super-shift AP-1 complex to a higher position. It suggested that the AP-1 complex was composed of Fra and Jun D in hippocampus of the seizure-sensitive rats. Western blot analysis further confirmed that Jun D proteins contained components of 43, 39 and 28 kDa. When secondary seizure stimulations were given to seizure-sensitive rats, the AP-1 DNA binding activity was attenuated and the components of AP-1 proteins changed transiently. In light of our results and those of literature, it appears that all the mentioned changes may play an important role in induction of long-lasting enhancement in seizure susceptibility.

Effects of taurine on reproduction and behaviour in GR/A mice

The characteristics of GR/A mice are rather poor pup growth and vigorous activity associated with increased excretion of taurine during pregnancy and lactation. The relationship between taurine and these characteristics were studied. The group of GR/A mice given a 1% taurine solution in their drinking water on the first day of pregnancy (day when the vaginal plug was found) (group I) or on the day of parturition (group II) differed little from the control group given tap water in all reproductive parameters, including pup growth. The spontaneous motor activities of both the female and male 4-month-old offspring of group I were markedly lower than those of the offspring of the control and group II, and than that of group III, which was given taurine after of weaning. These findings strongly suggest that taurine, possibly by acting on the developing brain at the fetal stage, has a long-term effect on the behaviour of this strain of mice, while it has little effect on their reproduction.

Effects of Ro 31-8220 on lipopolysaccharides-induced hepatotoxicity and release of tumor necrosis factor from rat Kupffer cells

AIM

To investigate protein kinase C (PKC) functions on lipopolysaccharide (LPS)-induced hepatotoxicity, a new potent PKC inhibitor Ro 31-8220 (Ro) was used to detect its effect on LPS-induced hepatotoxicity in rat hepatocytes and tumor necrosis factor (TNF) release from rat Kupffer cells (KC).

METHODS

Hepatocytes (containing KC) were incubated with LPS (10 mg.L-1) and Ro (0.1-10 mumol.L-1) for 24 h, alanine aminotransferase (AlaA) leakage in the culture as indication of hepatotoxicity. The TNF activity in the supernatant of rat KC culture with LPS in the presence of Ro (0.1-10 mumol.L-1) was monitored by the L929 target cell lytic assay.

RESULTS

Ro (0.1-10 mumol.L-1) reduced AlaA leakage in the hepatocyte culture. Ro inhibited dose-dependently the LPS-induced TNF production from rat KC.

CONCLUSION

PKC inhibitor Ro protects the hepatocytes from LPS-induced cytotoxicity and inhibits the LPS-induced TNF production from rat KC.

Schizosaccharomyces pombe is more sensitive to pressure stress than Saccharomyces cerevisiae

The effects of hydrostatic pressure on ultrastructure, microtubules and microfilaments of Schizosaccharomyces pombe were investigated by fluorescence microscopy, conventional electron microscopy and immunoelectron microscopy. Cells were treated with hydrostatic pressure from 0.1 to 400 MPa for 10 min at room temperature. The nuclear membrane was disrupted at above 100 MPa. At 150 MPa the matrixes of mitochondria had an electron dense area. At 250 MPa the cytoplasmic substances changed dramatically, the cellular organelles could hardly be detected and the fragmented nuclear membrane was barely visible. The fluorescence in alpha-tubulin was lost in most of the cells at 100 MPa. The gold particles for anti alpha-tubulin were not visible in the cells at the same level. Cell cycle specific actin distribution was lost even at 50 MPa, although actin dots localized at the central region remained unchanged. Thick actin cables appeared at 100 MPa. Complete depolymerization of F-actin was observed at 150 MPa. These results suggest that S. pombe cells were more sensitive than Saccharomyces cerevisiae cells. The damage to microtubules and nuclear membrane caused by hydrostatic pressure was though to be followed by breakdown of nuclear division apparatus and the inhibition of nuclear division. This damage might contribute to the frequent formation of polyploidy in S. pombe.

Inhibition of hepatitis B virus in vitro by antisense oligonucleotides

A series of antisense phosphorothioate oligodeoxynucleotides against hepatitis B virus (HBV) were synthesized and evaluated for their antiviral effect in Hep-G2 cells transfected with HBV genome. The inhibitory effect of the tested antisense oligonucleotides was sequence-specific, dose-and time-dependent, and synergistic for certain combinations. In virus-inhibitory concentrations the oligonucleotides were harmless to 2.2.15 cells. The most effective antisense oligonucleotides were found directed against the HBV mRNA transcribed from the cap site of SP II promoter, the portion of polyadenylation signal and the initiation region of gene S, with an inhibition of the HBsAg and HBeAg production by 85-95% and 50- 60%, respectively. To our surprise, antisense oligonucleotides directed against three key sites of HBV X gene blocked the expression of HBsAg, HBeAg and HBxAg. This fact might be related to the trans-activation of HBV X protein. Using radioisotope labelling, we demonstrated that Lipofectin promoted the cellular uptake and antiviral effect of antisense oligomers in 2.2.15 cells. These results suggest a therapeutic potential of antisense oligonucleotides in the treatment of patients chronically infected with HBV.

Effect of diallyl trisulfide on the activation of T cell and macrophage-mediated cytotoxicity

At high concentration (50 micrograms/ml), diallyl trisulfide (DATS) had an inhibitory effect on T cell activation (compared with control group, P < 0.05). But at appropriate concentrations (3.125-12.5 micrograms/ml), DATS augmented the activation of T lymphocytes by Con A (compared with control group, P < 0.01). The augmentation of T cell activation by DATS was related to its inhibitory effect on the production of nitric oxide (NO) by macrophages. In a wide range of concentrations (1-100 micrograms/ml), DATS can inhibit the production of NO by macrophages (P < 0.05, P < 0.01). In addition, DATS can antagonize the inhibition of tumor-derived immunosuppressive factors produced by S180 cells and Ehrlich ascitic cancer cells on the activation of T cells, and reduce the inhibitory rate significantly (P < 0.01). DATS, despite its inhibition of the production of NO by macrophages, can significantly enhance the production of hydrogen peroxide (H2O2) by macrophages. When macrophages were pretreated with DATS for 24 h, the cytotoxicity % of macrophages to three tumor cell lines was significantly higher than that in corresponding control group (P < 0.05, P < 0.01). In the presence of both DATS and LPS, the cytotoxicity of macrophages was further enhanced so that the cytotoxicity % of macrophages to tumor cells was significantly higher than either that in the presence of DATS alone or that in the presence of LPS alone (P < 0.05, P < 0.01). These results indicate that DATS can augment the activation of T cells and enhance the anti-tumor function of macrophage, suggesting that DATS may be potentially useful in tumor therapy.

Effect of "re du qing" on the activation, proliferation and membrane fluidity of lymphocytes

Effects of Chinese Medicinal Preparation "Re Du Qing" (RDQ) on the activation, proliferation and membrane fluidity of T lymphocytes from human peripheral blood were studied by means of 3H-TdR incorporation and DPH fluorescence polarization. The results showed that "RDQ" can: 1) significantly inhibit the activation of T lymphocytes; 2) restrain the proliferation of activated T lymphoblasts in the presence of exogenous interleukin-2 (IL-2); and 3) increase the membrane fluidity of T lymphocytes and antagonize the decreased fluidity of lymphocyte membrane mediated by Con A or PHA. The functional abnormalities of T lymphocytes in some autoimmune diseases such as arthritis and the usefulness of RDQ in the treatment of these diseases were also discussed.

Investigation on the effect of selenium on T lymphocyte proliferation and its mechanisms

The effects of selenium on T lymphocyte proliferation and its mechanisms have been investigated. The results showed that selenium is able to enhance lectin-stimulated T lymphocyte proliferation, to increase the production of interleukin 2 (IL-2) by lymphocytes and interleukin 1 (IL-1) by macrophages in the presence of lectin and to augment the response of T lymphoblasts to IL-2 and that of thymocytes to IL-1. The data presented suggest that selenium may be an important modulator for immune response. Selenium might enhance IL-2 production and response through the augmentation of IL-1 production and response, thereby promoting the enhancement of the proliferation and action of T lymphocytes and other immunocompetent cells. Based on these results, we may consider using selenium as an immunological enhancement agent to enhance or recover immune functions of the organism.

The yeast GLC7 gene required for glycogen accumulation encodes a type 1 protein phosphatase

The glc7 mutant of the yeast Saccharomyces cerevisiae does not accumulate glycogen due to a defect in glycogen synthase activation (Peng, Z., Trumbly, R. J., and Reimann, E.M. (1990) J. Biol. Chem. 265, 13871-13877) whereas wild-type strains accumulate glycogen as the cell cultures approach stationary phase. We isolated the GLC7 gene by complementation of the defect in glycogen accumulation and found that the GLC7 gene is the same as the DIS2S1 gene (Ohkura, H., Kinoshita, N., Miyatani, S., Toda, T., and Yanagida, M. (1989) Cell 57, 997-1007). The protein product predicted by the GLC7 DNA sequence has a sequence that is 81% identical with rabbit protein phosphatase 1 catalytic subunit. Protein phosphatase 1 activity was greatly diminished in extracts from glc7 mutant cells. Two forms of protein phosphatase 1 were identified after chromatography of extracts on DEAE-cellulose. Both forms were diminished in the glc7 mutant and were partly restored by transformation with a plasmid carrying the GLC7 gene. Southern blots indicate the presence of a single copy of GLC7 in S. cerevisiae, and gene disruption experiments showed that the GLC7 gene is essential for cell viability. The GLC7 mRNA was identified as a 1.4-kilobase RNA that increases 4-fold at the end of exponential growth in wild-type cells, suggesting that activation of glycogen synthase is mediated by increased expression of protein phosphatase 1 as cells reach stationary phase.

Role of monocyte fucose-receptors in T-cell fibronectin activity

T-cell fibronectin (FN) is a lymphokine produced by antigen- and mitogen-activated T cells that agglutinates human monocytes at femtomolar concentrations. This extreme degree of activity derives from co-operative interactions between multiple FN domains and multiple monocyte integrin protein receptors. T-cell FN, like other FN, is a glycoprotein. The role interactions between T-cell FN carbohydrate and lectin-like monocyte surface receptors play in mediating T-cell FN activity was studied by determining the ability of monosaccharides to inhibit T-cell FN activity. L-Fucose and L-rhamnose significantly inhibited T-cell FN-mediated monocyte agglutination at concentrations as low as 0.01 mM; D-glucose, D- or L-galactose, D- or L-mannose and D-fucose were not inhibitory at 10-100 mM. This inhibition appeared to be due to interference with the binding of T-cell FN fucose residues to monocyte fucose receptors since: (i) treatment of T-cell FN with alpha-L-fucosidase abolished its agglutinating activity for human monocytes, while treatment with beta-D-galactosidase or with alpha-L-fucosidase in the presence of L-fucose had no effect; (ii) treatment of monocytes with alpha-L-fucosidase did not affect their response to T-cell FN; and (iii) L-fucose or L-rhamnose did not alter the expression of monocyte integrin FN receptors under conditions where T-cell FN-mediated monocyte agglutination was completely inhibited. In vivo, 1 mumol intracutaneous L-fucose inhibited expression of delayed hypersensitivity by 30% (P much less than 0.001); similar doses of L-rhamnose inhibited responses by 10% (P less than 0.02). These data implicate a fucose receptor in monocyte response to T-cell FN, and suggest that T-cell FN is only one of the mediators involved in initiating delayed hypersensitivity reactions in vivo.

Effect of arginine on immune function in rats with obstructive jaundice

In this study we used an experimental model produced by bile duct ligation (BDL) in rats to demonstrate relation between immune function and susceptibility to infection associated with obstructive jaundice and immunoregulatory effect of arginine in BDL rats. Our experimental results showed that thymus weight, content of lymphocytes in thymus and responsiveness to Con A in vitro were dramatically reduced in BDL rats as compared to rats with sham operation and that the impairment of lymphocyte function was significantly related to the susceptibility to infection. Arginine, as a T cell stimulator, markedly improved immune function and decreased susceptibility to infection of BDL rats.

Effect of immunosuppressive factor produced by human lung cancer cell line A549 on the production and action of interleukin 1

A549, a human lung cancer cell line, spontaneously produces a tumor-derived immunosuppressive factor (TDSF) which inhibits the production and action of interleukin 1 (IL-1). After exposure of macrophages to TDSF for 5 h, the production of IL-1 by macrophages was significantly inhibited. The inhibition was much stronger if TDSF existed continuously in macrophage culture. The response of thymocytes treated with nylon wool to exogenous IL-1 was significantly suppressed in the presence of TDSF, suggesting that TDSF can inhibit the action of IL-1. The thymocytes untreated with nylon wool could proliferate after being stimulated with Con A. The proliferation was significantly suppressed by TDSF in a dose-dependent manner. These results suggest that the inhibitory action of TDSF on T cell activation is associated with IL-1, and that TDSF might exert an inhibitory action on other reactions mediated by IL-1. Furthermore, TDSF can reduce the supplementation of new T cells by inhibiting the proliferation of thymocytes.

Effect of tumor-derived immunosuppressive factor(s) on interleukin 2 and on expression of interleukin 2 receptor

In this paper, we have described the effects of tumor-derived immunosuppressive factor(s) (TDSF) on interleukin 2 (IL-2) production, on IL-2 responsiveness and on the expression of IL-2 receptors. The results showed that TDSF was able to markedly inhibit the production of IL-2 from PHA-stimulated lymphocytes and IL-2-dependent proliferation of activated lymphocytes, and to partially inhibit the expression of IL-2 receptor. These results suggest that inhibiting IL-2 production and responsiveness may be a major mechanism by which TDSF inhibit T lymphocyte proliferation and other immune responses. That TDSF exerted a very potent inhibiting action on IL-2 responsiveness is especially noticeable if we consider using IL-2 as an immunotherapeutic agent. This may be an important reason why treatment of tumor with IL-2 did not yield satisfactory results so far.

Investigation on the inhibitory effect of tumor-derived immunosuppressive factor(s) on T lymphocyte proliferation

Using five tumor cell lines, the effect of tumor-derived immunosuppressive factor(s) (TDSF) on T lymphocyte proliferation and its mechanism have been investigated. It was found that TDSF markedly inhibited PHA-stimulated T lymphocyte proliferation via a noncytotoxic mechanism. The inhibition increased in dose-dependent manner and the maximum inhibition was achieved when the factor was added at the initiation of the culture. When PBMC were preincubated with supernatants of tumor cells for 24 h, washed extensively and then cocultured with freshly prepared PBMC, similar suppressive effects were observed. The above results indicated that the activation of any suppressor cell subgroup may be one of the mechanisms of immunosuppressive action of TDSF.

Biologic characteristics of an immunosuppressive factor derived from a human lung cancer cell line

A 549, a human lung cancer cell line, spontaneously produces a tumor-derived immunosuppressive factor (TDSF) which inhibited PHA-stimulated T lymphocyte proliferation via a noncytotoxic mechanism. The inhibition increased in a dose-dependent pattern. The factor also markedly suppressed production of interleukin (IL-2) by PHA-stimulated lymphocytes and IL 2-dependent proliferation of activated lymphocytes. The fact that TDSF possessed very potent inhibitive action on IL-2 is especially noteworthy if we consider the use of IL-2 as immunotherapeutic agent. The synthesis of the factor was inhibited by mitomycin C, actinomycin D and cycloheximide, indicating that the factor is a genic product of A 549 cells. The factor is chemically a protein with a molecular weight greater than 150 KD and sensitive to extremes of pH, heating to 60 degrees C and trypsin treatment.