[A multicenter clinical trial of collar-button type keratoprosthesis implantation for the treatment of corneal blindness in high-risk transplantation]

Objective: To evaluate the efficiency and safety of collar-button type keratoprosthesis (c-bKPro) implantation for corneal blindness in high-risk transplantation in China. Methods: It was a case series study. High-risk corneal blind patients who planned to undergo c-bKPro implantation were prospectively and continuously enrolled in the Eye Hospital of Shandong First Medical University, Ophthalmology Division of Chinese PLA General Hospital, Zhongshan Ophthalmic Center, Department of Ophthalmology in Eye & ENT Hospital of Fudan University, and Eye Hospital of Wenzhou Medical University from July 2019 to January 2020. The cure for blindness and surgical success were assessed based on visual acuity (VA)≥0.05. The complications and keratoprosthesis retention rate were recorded to determine the safety of the surgery. Results: Thirty-seven subjects (eyes) were included, of which 32 were male and 5 were female, aged 27 to 72 years old. The indications of c-bKPro implantation were corneal graft failure (21 eyes, 56.8%), chemical injury (8 eyes, 21.6%), thermal burn (5 eyes, 13.5%), unexplained corneal opacity (2 eyes, 5.4%), and corneal perforation (1 eye, 2.7%). Two patients withdrew from the clinical trial at 3 months postoperatively. Thirty-five patients were followed up for 6 months, and 31 were followed up for 12 months. The VA was ≥0.05 in 83.8% of eyes at 6 months and in 81.8% of eyes at 12 months. Among the 11 eyes diagnosed with concurrent glaucoma, 6 eyes achieved a VA of ≥0.05. At 12 months, the c-bKPro retention rate was 100%. The surgical complications included retroprosthetic membrane formation (5 eyes, 16.1%), persistent corneal epithelial defects (5 eyes, 16.1%), macular edema (4 eyes, 12.9%), new-onset glaucoma (4 eyes, 12.5%; including one eye withdrawn from the study at 3 months), sterile corneal melting (2 eyes, 6.5%), sterile vitritis (1 eye, 3.2%), and infectious keratitis (1 eye, 3.2%). Conclusions: C-bKPro implantation is an effective and safe option for treating corneal blindness in high-risk transplantation in China. Improved visual outcomes could be achieved in most cases, with a relatively low incidence of postoperative complications.

Honokiol Reduces Mitochondrial Dysfunction and Inhibits Apoptosis of Nerve Cells in Rats with Traumatic Brain Injury by Activating the Mitochondrial Unfolded Protein Response

This study was designed to determine the effects and underlying mechanism of honokiol (HNK) on traumatic brain injury (TBI). A rat TBI model was constructed using the modified Feeney free-fall percussion method and treatment with HNK via intraperitoneal injection. The brain tissues of the rats in each group were assessed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay to detect the level of neuronal apoptosis. Western blots were used to detect the expression levels of apoptosis-related proteins (Bcl-2 and Bax), and ELISAs were used to measure the levels of pro-inflammatory cytokines (IL-18 and IL-1β) and the activity of caspase-1. In addition, the mitochondrial membrane potential, reactive oxygen species (ROS), and adenosine 5'-triphosphate (ATP) were also measured. Western blots and qRT-PCRs were used to determine the relative expression levels of the mitochondrial unfolded protein response (UPRmt)-related proteins and mRNAs. Based on the experimental results, treatment with HNK was associated with a decrease in the number of TUNEL-positive cells, downregulated Bax expression levels, elevated Bcl-2 expression levels, and inhibition of neuronal apoptosis in the brain tissue of TBI rats. HNK also suppressed neuroinflammation by decreasing IL-1β and IL-18 levels and caspase-1 activity. Additionally, HNK lowered the mitochondrial membrane potential and ROS levels, increased ATP levels, and improved mitochondrial dysfunction in neural cells. Furthermore, in the investigation of the mechanism of HNK on TBI, we observed that HNK could activate UPRmt by upregulating the mRNA and protein expression levels of HSPA9, CLPP, and HSP60 in the brain tissues of TBI rats. Collectively, HNK reduced mitochondrial dysfunction, inhibited the apoptosis of nerve cells, and attenuated inflammation in the brains of TBI rats. The protective effect of HNK may be achieved through the activation of UPRmt.

Bioselective Synthesis of a Porous Carbon Collector for High-Performance Sodium-Metal Anodes

Biomass-derived carbon materials prepared via pyrolysis from natural wood structures show potential for a storage application. Natural wood is composed of multiple carbon sources, including lignin, hemicellulose, and cellulose, which influence the formation and microstructure of pyrolysis carbon. However, the mechanism is not fully understood. In this work, vast lignin is selectively consumed via biodegradation with fungi from basswood. The results demonstrate that the as-prepared carbon material has a short-range ordered graphitic structure after thermal treatment. The improved graphitization degree of carbon suggests that cellulose is beneficial to graphite formation during pyrolysis. The elevated graphitization degree helps to improve the charge transfer and the thermodynamic stability of the electrode reaction. As a proof of concept, the obtained carbon current collector as a sodium-metal anode can undergo cycling at an areal capacity of 10 mAh cm^-2 for over 4500 h and yield an excellent Coulombic efficiency of >99.5%.

Edible fungus slag derived nitrogen-doped hierarchical porous carbon as a high-performance adsorbent for rapid removal of organic pollutants from water

In this work, agricultural waste edible fungus slag derived nitrogen-doped hierarchical porous carbon (EFS-NPC) was prepared by a simple carbonization and activation process. Owing to the biodegradation and infiltrability of hyphae, this EFS-NPC possessed an ultra-high specific surface area (3342 m²/g), large pore volume (1.84 cm³/g) and abundant micropores and mesopores. The obtained EFS-NPC could effectively adsorb bisphenol A (BPA) with the maximal adsorption capacity of 1249 mg/g and the removal process reached 89.9% of the equilibrium uptake in the first 0.5 h. Besides, the EFS-NPC showed much better removal performance towards 2,4-dichlorophenol (2,4-DCP) and methylene blue (MB) than commercial activated carbons (Norit RO 0.8 and DARCO granular activated carbon). Furthermore, adsorption isotherms, thermodynamics and kinetics researches indicated that the adsorption process of BPA was monolayer, exothermic and spontaneous. This research has given evidence that the low-cost EFS-NPC can serve as a high-efficient adsorbent for removing organic contaminants from water.

Guiding Uniform Li Plating/Stripping through Lithium-Aluminum Alloying Medium for Long-Life Li Metal Batteries

The uncontrolled growth of Li dendrites upon cycling might result in low coulombic efficiency and severe safety hazards. Herein, a lithiophilic binary lithium-aluminum alloy layer, which was generated through an in situ electrochemical process, was utilized to guide the uniform metallic Li nucleation and growth, free from the formation of dendrites. Moreover, the formed LiAl alloy layer can function as a Li reservoir to compensate the irreversible Li loss, enabling long-term stability. The protected Li electrode shows superior cycling over 1700 h in a Li|Li symmetric cell.

Total hip arthroplasty following failure of tantalum rod implantation for osteonecrosis of the femoral head with 5- to 10-year follow-up

BACKGROUND

Total hip arthroplasty (THA) with failure of tantalum rod implant for osteonecrosis of the femoral head (ONFH) will be the only choice for patients. However,it remains unknown whether tantalum rod implantation has an adverse effect on the survival time of implants following conversion to THA. The aim of this study was to retrospectively evaluate the clinical and radiographic outcomes of conversion to THA in patients who were previously treated with implantation of a tantalum rod.

METHODS

This study included 31 patients (39 hips), who underwent conversion to THA due to failure of core decompression with an implanted tantalum rod. Among these 31 patients, 26 patients were male and five patients were female. The mean age of these patients was 49.3 years old (range: 36-64 years old). The control group included 33 patients (40 hips), who underwent total hip replacement without tantalum rod implantation. The hip Harris score, implant wear, osteolysis, radiolucencies and surgical complications were recorded during the follow-up. The distribution of tantalum debris in the proximal, middle and distal periprosthetic femoral regions, radiolucent lines and osteolysis were analyzed on post-operative radiographs.

RESULTS

There were no significant differences in Harris score, liner wear and complications between the two groups (P > 0.05). Osteolysis and radiolucent lines more likely occurred in patients with tantalum debris distributed in three regions than in one or two regions (P < 0.05).

CONCLUSIONS

The mid-term clinical outcome of patients who underwent THA with tantalum rod implantation was not different from those without a tantalum rod, suggesting that tantalum debris did not increase the liner wear rate. However, the distribution of periprosthetic tantalum debris in the proximal, middle and distal femoral regions may increase the risk of femoral osteolysis and radiolucent lines.

[Dynamic expression of carnitine palmitoyltransferase II in the mitochondrial inner membrane during hepatocyte malignant transformation induced by lipid accumulation]

Objective: To investigate the dynamic expression of hepatic carnitine palmitoyltransferase-II (CPT-II) in the mitochondrial inner membrane during hepatocyte malignant transformation induced by lipid accumulation. Methods: Male Sprague-Dawley rats were divided randomly into control, fatty liver, and induced cancer groups, which were fed with normal, high-fat (HF), and HF containing 2-fluorenylacetamide (0.05%, 2-FAA) diets, respectively, for 14 weeks. One rat from each group was sacrificed every two weeks and the blood and liver samples were collected. Liver morphological changes were evaluated with hematoxylin and eosin staining, and the liver tissue samples were divided into control, fatty liver, degeneration, precancerous, and cancerous groups accordingly. Hepatic lipids were dyed by the oil red O method. The CPT-II expression was measured by immunohistochemistry and compared with the specific CPT-II concentration (ng/mg liver protein, ng/mg P) among different groups. Serum levels of circulating total cholesterol (Tch), triglyceride (TG), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were quantitatively analyzed. Results: Massive lipid accumulation hepatocytes was seen in rats on HF and HF containing 2-FAA diets. The lipid levels in the control group were significantly lower than those in the fatty liver (t = -11.556, P < 0.001), degeneration (t = -4.847, P = 0.04), precancerous (t = -13.652, P = 0.005), and cancerous groups (t = -10.896, P = 0.008). The serum TG and Tch levels in the degeneration, precancerous, and cancerous groups were 2-3 times higher than those in the control group (P < 0.05). After 2-FAA treatment, the morphological changes of rat hepatocytes showed the progression from degeneration and precancerosis to cancerosis, with hepatocyte injury. The serum AST and ALT levels in the degeneration, precancerous, and cancerous groups were significantly higher (4-8 times) than those in the control group (P < 0.05). The specific concentration of liver CPT-II expression was significantly reduced during hepatocyte malignant transformation, as confirmed by immunohistochemistry, with the CPT-II levels significantly lower in the cancerous group than in any of other groups (P < 0.05). Conclusion: Low hepatic CPT-II expression might lead to abnormal lipid accumulation in hepatocytes, which should promote the malignant transformation of hepatocytes.

Facile Synthesis of Carbon-Coated Spinel Li4Ti5O12/Rutile-TiO2 Composites as an Improved Anode Material in Full Lithium-Ion Batteries with LiFePO4@N-Doped Carbon Cathode

The spinel Li₄Ti₅O₁₂/rutile-TiO₂@carbon (LTO-RTO@C) composites were fabricated via a hydrothermal method combined with calcination treatment employing glucose as carbon source. The carbon coating layer and the in situ formed rutile-TiO₂ can effectively enhance the electric conductivity and provide quick Li⁺ diffusion pathways for Li₄Ti₅O₁₂. When used as an anode material for lithium-ion batteries, the rate capability and cycling stability of LTO-RTO@C composites were improved in comparison with those of pure Li₄Ti₅O₁₂ or Li₄Ti₅O₁₂/rutile-TiO₂. Moreover, the potential of approximately 1.8 V rechargeable full lithium-ion batteries has been achieved by utilizing an LTO-RTO@C anode and a LiFePO₄@N-doped carbon cathode.

[Abnormal expression of insulin-like growth factor-I receptor and inhibitory effect of its transcription intervention on nude mice xenograft tumor]

Objective: To investigate the expression of insulin-like growth factor-I receptor (IGF-IR) in liver cancer and the inhibitory effect of its transcription intervention on nude mice xenograft tumor. Methods: A total of 40 patients with primary liver cancer were enrolled, and 40 samples of cancer lesions, peri-cancerous tissues (with a distance of 2 cm to the margin of cancer lesion), or distal liver tissues (with a distance of 5 cm to the margin of cancer lesion), with a weight of 200 mg, were collected after surgery. Some of these samples were used for pathological examination, and the rest were stored at -85°C. A total of 18 BALB/c nude mice aged 4-6 weeks with a body weight of 18-20 g (9 male and 9 female mice) were randomly divided into control group, negative control group, and co-intervention group, with 6 mice in each group, and fed under specific pathogen-free conditions. The cell line was cultured in the dimethyl sulfoxide complete medium containing 10% fetal bovine serum in a CO₂incubator at 37°C. When the cell confluence reached 90% after cell inoculation, shRNA was divided into co-intervention group, negative control group, and untreated control group and were transfected to hepatoma cells using PolyJetTM transfection reagent. Stable cell clones obtained by G418 screening and used for the in vivo study. Immunohistochemistry, Western blotting, and quantitative real-time PCR were used to analyze the expression of IGF-IR in the human hepatoma tissue and cell line. The IGF-IR shRNA eukaryotic expression plasmids were established and screened for the most effective sequence; they were transfected to PLC/PRF/5 hepatoma cells, and the CCK-8 assay was used to analyze the changes in cell proliferation. The stable cell line screened out by G418 was inoculated to establish the subcutaneous xenograft tumor in nude mice. The tumor growth curve was plotted and histological examination was performed. Graphpad Prism 5.0 and SPSS 18.0 were used for plotting and data analysis; the variance test and Q test were used for comparison of means between multiple samples, the t-test was used for comparison of means between any two samples, the chi-square test or Fisher's exact test was used for comparison of rates between samples, and a rank correlation analysis was performed for expression intensity. Results: The liver cancer group had a significantly higher positive rate of IGF-IR than the peri-cancerous group and distal tissue group (82.5% vs 42.5%/10%,χ²= 13.653 and 42.29, bothP< 0.01), as well as significantly higher expression intensity than these two groups (Z= 4.771 and 6.579, bothP< 0.01). IGF-IR was not significantly expressed in the L02 cell line and was strongly expressed in the PLC/PRF/5 hepatoma cells, and the expression intensity of IGF-IR in the PLC/PRF/5 hepatoma cells was 4 and 5 times that in Bel-7404 cells and HepG2 cells, respectively. After the PLC/PRF/5 hepatoma cells were transfected with shRNA4 with the best co-intervention effect, the mean inhibition rate of tumor cell growth reached 63.9% at 72 hours, and the mean inhibition rate of IGF-IR transcription reached 59.6%. Tumor cells were arrested in G1 phase, and there was a significant increase in apoptosis rate. As for the subcutaneous hepatoma xenograft in nude mice, the intervention group had significantly slower tumor growth than the blank control group and negative control group (143±24 mm3 vs 372±46 mm3/350±50 mm3,t= 10.776 and 9.142, bothP< 0.01); the intervention group had significantly downregulated IGF-IR expression, which was significantly lower than that in the blank control group and negative control group (t= 11.184 and 9.450, bothP< 0.01). Conclusion: Intervention of IGF-IR transcription can effectively inhibit the growth of xenograft tumor in nude mice, suggesting that IGF-IR gene might become a new potential target for the treatment of liver cancer.

Interval multistage joint-probabilistic integer programming approach for water resources allocation and management

In this study, an interval multistage joint-probabilistic integer programming method was developed to address certain problems in water resource regulation. This method effectively deals with data in the form of intervals and probability distribution. It can also process uncertain data in the form of joint probabilities. The proposed method can also reflect the linkage and dynamic variability between particular stages in multi-stage planning. Sensitivity analysis on moderate violations and security constraints showed that the degree of constraint violation was closely linked to the final benefits of the system. The developed method was applied in the case study of the joint-operation of the Tianzhuang and Bashan Reservoirs in Huaihe River, China. In this case study, the proposed method can deal with the water shortage problems downstream and the distribution problems caused by excess water in the reservoir. It can also guarantee the optimization of long-term water usage of both Reservoirs and the river downstream.

Inhibition of T lymphocyte activation in mice heterozygous for loss of the IMPDH II gene

Inosine 5'-monophosphate dehydrogenase (IMPDH) is the rate-limiting enzyme in the de novo synthesis of guanine nucleotides, which are also synthesized from guanine by a salvage reaction catalyzed by the X chromosome-linked enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Since inhibitors of IMPDH are in clinical use as immunosuppressive agents, we have examined the consequences of knocking out the IMPDH type II enzyme by gene targeting in a mouse model. Loss of both alleles of the gene encoding this enzyme results in very early embryonic lethality despite the presence of IMPDH type I and HPRT activities. Lymphocytes from IMPDH II(+/-) heterozygous mice are normal with respect to subpopulation distribution and respond normally to a variety of mitogenic stimuli. However, mice with an IMPDH II(+/-), HPRT(-/o) genotype demonstrate significantly decreased lymphocyte responsiveness to stimulation with anti-CD3 and anti-CD28 antibodies and show a 30% mean reduction in GTP levels in lymphocytes activated by these antibodies. Furthermore, the cytolytic activity of their T cells against allogeneic target cells is significantly impaired. These results demonstrate that a moderate decrease in the ability of murine lymphocytes to synthesize guanine nucleotides during stimulation results in significant impairment in T-cell activation and function.

Differential actions of neurotrophins on apoptosis mediated by the low affinity neurotrophin receptor p75NTR in immortalised neuronal cell lines

The low affinity neurotrophin receptor (p75NTR) mediates apoptosis of a number of neuronal and non-neuronal cells but the signals leading to the apoptosis remain obscure. To reveal the mechanism of p75NTR-mediated apoptosis, a neural cell line expressing human p75NTR was established. The human cDNA fragment encoding for p75NTR was PCR-amplified, cloned into the retrovirus expression vector pXT-1 and transfected into the rat cerebellum cell line R2. The expression of p75NTR in the R2 cell line was demonstrated by both Northern blotting analysis and immunocytochemistry. Serum withdrawal induced dramatic apoptosis in p75NTR-expressing R2 cells (R2L1) but not in pXT-1 transfected control R2 cells (R2P). Reverse transcription polymerase chain reaction (RT-PCR) revealed that these cell lines express trkA and trkB but not trkC. The apoptosis of R2L1 cells triggered by the serum deprivation for 48 h was completely prevented by neurotrophin-3 and the antibody to p75NTR but only partially prevented by the nerve growth factor and brain derived neurotrophic factor. We conclude that the p75NTR mediates apoptosis of R2L1 cells by its intrinsic receptor effects requiring an unbound status of this receptor and that the apoptosis is prevented by neurotrophins or the antibody to p75NTR through distinct mechanisms.

Inosine-5'-monophosphate dehydrogenase: regulation of expression and role in cellular proliferation and T lymphocyte activation

Guanine nucleotide synthesis is essential for the maintenance of normal cell growth and function, as well as for cellular transformation and immune responses. The expression of two genes encoding human inosine-5'-monophosphate dehyrogenase (IMPDH) type I and type II results in the translation of catalytically indistinguishable enzymes that control the rate-limiting step in the de novo synthesis of guanine nucleotides. Cellular IMPDH activity is increased more than 10-fold in activated peripheral blood T lymphocytes and is attributable to the increased expression of both the type I and type II enzymes. In contrast, abrogation of cellular IMPDH activity by selective inhibitors prevents T lymphocyte activation and establishes a requirement for elevated IMPDH activity in T lymphocytic responses. In order to assess the molecular mechanisms governing the expression of the IMPDH type I and type II genes in resting and activated peripheral blood T lymphocytes, we have cloned the human IMPDH type I and type II genes and characterized their genomic organization and their respective 5'-flanking regions. Both genes contain 14 highly conserved exons that vary in size from 49 to 207 base pairs. However, the intron structures are completely divergent, resulting in disparities in gene length (18 kilobases for type I and 5.8 kilobases for type II). In addition, the 5'-regulatory sequences are highly divergent; expression of the IMPDH type I gene is controlled by three distinct promoters in a tissue specific manner while the type II gene is regulated by a single promoter and closely flanked in the 5' region by a gene of unknown function. The conservation of the IMPDH type I and type II coding sequence in the presence of highly divergent 5'-regulatory sequences points to a multifactorial control of enzyme expression and suggests that tissue-specific and/or developmentally specific regulation of expression may be important. Delineation of these regulatory mechanisms will aid in the elucidation of the signaling events that ultimately lead to the synthesis of guanine nucleotides required for cellular entry into S phase and the initiation of DNA replication.

Regulation of the human inosine monophosphate dehydrogenase type I gene. Utilization of alternative promoters

Catalysis of guanine nucleotide formation from IMP in the de novo purine synthetic pathway is carried out by two isoforms of the enzyme inosine monophosphate dehydrogenase (IMPDH) that are catalytically indistinguishable but are encoded by separate genes. In order to assess the potential for cell type-specific expression of IMPDH activity, we have characterized the IMPDH type I gene and identified three major RNA transcripts that are differentially expressed from three different promoters. A 4.0-kilobase pair (kb) mRNA containing 1.3 kb of 5'-untranslated region is expressed in activated peripheral blood lymphocytes and to a far lesser extent in cultured tumor cell lines. The P1 promoter that regulates the transcription of this mRNA has a high degree of sequence identity to an Alu repetitive sequence. A transcript of 2.7 kb is found in a subset of the tumor cell lines examined, whereas a 2.5-kb mRNA species is universally expressed and is the prevalent mRNA in most cell lines and tissues. The relative strengths of the three promoter regions and the effects of variable extents of 5'-flanking sequence on the P3 promoter differ in Jurkat T, as compared with Raji B lymphoid cell lines, demonstrating a complex cell type-specific transcriptional regulation of IMPDH type I gene expression.

Inosine monophosphate dehydrogenase expression: transcriptional regulation of the type I and type II genes

Inosine 5'-monophosphate dehydrogenase (IMPDH) is an essential rate-limiting enzyme in the de novo guanine nucleotide synthetic pathway that catalyzes the conversion of IMP to XMP. Enzyme activity is accounted for by the expression of two distinct but closely related genes termed IMPDH I and II. Increased IMPDH activity has been linked to both cellular proliferation and neoplastic transformation and generally ascribed to an increase in the expression of the type II gene. We have characterized the type I and type II genes and identified elements important in the transcriptional regulation of both genes. The type II IMPDH gene contains a 466 bp 5' flanking region spanning the translation start site that contains several transcription factor binding sites and mediates increased transcription of a CAT reporter gene in peripheral blood T lymphocytes when these cells are induced to proliferate. The single functional IMPDH type I gene contains exon-intron boundaries and exon structures that are nearly identical to those in the type II gene. In contrast to the type II gene, however, it contains two putative promoter sites, each with the potential for transcriptional regulation. We conclude that these two genes most probably arose from an early gene duplication event and that their highly conserved structures and differential regulation at the transcriptional level argue strongly for a significant role for each gene in cellular metabolism, growth, and differentiation.

[The clinical observation of tetracycline stained teeth covered by composite resin veneer induced of secondary gingivitis]

Using gingival index,sulcus bleeding index and plaque index of 765 tetracycline stained teeth covered by composite resin veneer after 1/2-3 years were observed.It was found that the incidence of gingivitis was over 60%.The reexamination after three months later showed that the three indexes were significantly improved by grinding teeth proper and teaching standard brushing method.

Induction by concanavalin A of specific mRNAs and cytolytic function in a CD8-positive T cell hybridoma

A previous report from this laboratory described the production of CD8+, class I-specific T cell hybridomas which developed specific cytolytic activity and the ability to secrete IL-2 upon Con A or specific Ag stimulation. Unlike normal lymphocytes or long-term CTL lines for which exposure to Ag triggers both differentiation and proliferation, T cell hybridoma lines can be activated functionally against a background of continuous proliferation. They therefore provide a unique system with which to study the molecular events involved in the induction of cytolytic function. The expression of mRNA from a series of genes was evaluated by Northern hybridization at various times after Con A stimulation of the H-2Ld-specific CD8+ 3D9 hybridoma. Induction of the c-fos proto-oncogene by 45 min poststimulation was followed shortly by c-myc induction. Perforin mRNA was expressed at a low level in the unstimulated hybridomas, but was down-regulated upon Con A stimulation to levels undetectable by PCR. Interestingly, production of granzyme A mRNA was strongly induced by 45 min after Con A stimulation. In the CD8+ RT-1.3G3 hybridoma, which is nonlytic and specific for the HIV-1 envelope glycoprotein, c-fos but not granzyme A mRNA was induced by 45 min poststimulation, and no granzyme A mRNA was detectable at any time. Thus, a significant role for granzyme A in the induction of cytolytic activity is suggested. Cytolysis by the 3D9 hybridoma involved both target cell membrane damage and DNA fragmentation, and both Ca(2+)-dependent and Ca(2+)-independent cytolysis were observed. Although TNF-alpha mRNA was induced by 4 h poststimulation, Ab to TNF-alpha failed to inhibit the Ca(2+)-independent lysis observed, leaving the basis for the observed Ca(2+)-independent lysis unexplained.

Induction by concanavalin A of specific mRNAs and cytolytic function in a CD8-positive T cell hybridoma

A previous report from this laboratory described the production of CD8+, class I-specific T cell hybridomas which developed specific cytolytic activity and the ability to secrete IL-2 upon Con A or specific Ag stimulation. Unlike normal lymphocytes or long-term CTL lines for which exposure to Ag triggers both differentiation and proliferation, T cell hybridoma lines can be activated functionally against a background of continuous proliferation. They therefore provide a unique system with which to study the molecular events involved in the induction of cytolytic function. The expression of mRNA from a series of genes was evaluated by Northern hybridization at various times after Con A stimulation of the H-2Ld-specific CD8+ 3D9 hybridoma. Induction of the c-fos proto-oncogene by 45 min poststimulation was followed shortly by c-myc induction. Perforin mRNA was expressed at a low level in the unstimulated hybridomas, but was down-regulated upon Con A stimulation to levels undetectable by PCR. Interestingly, production of granzyme A mRNA was strongly induced by 45 min after Con A stimulation. In the CD8+ RT-1.3G3 hybridoma, which is nonlytic and specific for the HIV-1 envelope glycoprotein, c-fos but not granzyme A mRNA was induced by 45 min poststimulation, and no granzyme A mRNA was detectable at any time. Thus, a significant role for granzyme A in the induction of cytolytic activity is suggested. Cytolysis by the 3D9 hybridoma involved both target cell membrane damage and DNA fragmentation, and both Ca(2+)-dependent and Ca(2+)-independent cytolysis were observed. Although TNF-alpha mRNA was induced by 4 h poststimulation, Ab to TNF-alpha failed to inhibit the Ca(2+)-independent lysis observed, leaving the basis for the observed Ca(2+)-independent lysis unexplained.

Assignment of the human type I IMP dehydrogenase gene (IMPDH1) to chromosome 7q31.3-q32)

Two phage lambda clones that contain the 5' portion of the human type I inosine 5'-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205) gene were isolated. Both polymerase chain reaction analysis of a panel of human-mouse and human-hamster cell somatic hybrids using primers specific for the type I IMPDH gene and fluorescence in situ hybridization with metaphase human chromosomes using type I IMPDH genomic DNA as probes indicate that the type I IMPDH gene (symbol IMPDH1) is located on chromosome 7. Sequential GTG-banding was performed to assign the band location of the type I IMPDH gene to chromosome 7q31.3-q32.

Ciliary neurotropic factor, interleukin 11, leukemia inhibitory factor, and oncostatin M are growth factors for human myeloma cell lines using the interleukin 6 signal transducer gp130

Interleukin 6 (IL-6) is a major growth factor for tumor plasma cells involved in human multiple myeloma (MM). In particular, human myeloma cell lines (HMCL), whose growth is completely dependent on addition of exogenous IL-6, can be obtained reproducibly from every patient with terminal disease. Four cytokines, ciliary neurotropic factor (CNTF), IL-11, leukemia inhibitory factor (LIF), and oncostatin M (OM), use the same transducer chain (signal transducer gp130) as IL-6 and share numerous biological activities with this IL. We found that these four cytokines stimulated proliferation and supported the long-term growth of two out of four IL-6-dependent HMCL obtained in our laboratory. Half-maximal proliferation was obtained with cytokine concentrations ranging from 0.4 to 1.2 ng/ml for IL-11, LIF, and OM. CNTF worked at high concentrations only (90 ng/ml), but addition of soluble CNTF receptor increased sensitivity to CNTF 30-fold. The growth-promoting effect of these four cytokines was abrogated by anti-gp130 antibodies, contrary to results for anti-IL-6 receptor or anti-IL-6 antibodies. No detectable changes in the morphology and phenotype were found when myeloma cells were cultured with one of these four cytokines instead of IL-6. Concordant with their IL-6-dependent growth, the four HMCL expressed membrane IL-6R and gp130 detected by FACS analysis. LIF-binding chain gene (LIFR) was expressed only in the two HMCL responsive to LIF and OM.

Differential susceptibility of mouse Lyt-2 and Lyt-3 genes to negative regulation

Hybrids of Lyt-2/Lyt-3-positive class I-specific cytotoxic T lymphocytes (CTLs) with the BW5147 thymoma cell line (Lyt-2/Lyt-3-negative) are known to be Lyt-2/Lyt-3-negative due to shutoff of transcription of the CTL's Lyt-2 gene. Hybrids of a constitutively Lyt-2-positive transfectant of BW5147 (3B2) with a long term CTL line, 2C, and with CTLs generated in a mixed leucocyte reaction (MLR) shut off the CTL's Lyt-2 gene as expected but express the CTL's Lyt-3 gene product as a heterodimer with the product of the transfected Lyt-2 gene. Thus the Lyt-3 gene is not subject to the same negative regulatory influences as the Lyt-2 gene. That expression of Lyt-2 is not necessary for Lyt-3 gene transcription to continue is demonstrated by the finding that hybrids of MLR-generated CTLs with either BW5147 (Lyt-2-negative) or 3B2 (Lyt-2-positive) cells express Lyt-3 RNA. Southern hybridization and structural analysis of DNA fragments generated using the polymerase chain reaction demonstrated that hybrids contain several species of Lyt-3 RNA, one of which lacks the exon encoding the extracellular V-like domain and appears to be the product of an alternatively-spliced RNA transcript.

Inducible functions in hybrids of a Lyt-2+ BW5147 transfectant and the 2C CTL line

Cytolytic activity and release of interleukin 2 (IL-2) were induced in Lyt-2-positive T-T cell hybrids by incubation with either concanavalin A or irradiated stimulator cells. Since hybrids of Lyt-2-positive class I-specific cytotoxic T lymphocytes (CTLs) with the fusable mouse thymoma cell line, BW5147, are invariably Lyt-2-negative, a derivative of BW5147 was produced by transfection which constitutively expresses surface Lyt-2.1. This cell line, 3B2, was fused with the H-2Ld-specific long term CTL line, 2C. Such hybrids expressed the transfected Lyt-2 gene but not the endogenous gene of the 2C fusion partner. That Lyt-2 plays a functional role in hybrids of 3B2 with 2C is shown by the observations that: 1) cytolysis by Lyt-2-positive hybrids was inhibited by Lyt-2-specific monoclonal antibody (mAb); 2) Lyt-2-positive but not Lyt-2-negative subclones of one such line develop specific cytotoxicity when incubated with stimulator cells; 3) Less IL-2 was released from Lyt-2-negative subclones incubated with stimulator cells than from Lyt-2-positive subclones; 4) Lyt-2-specific mAb inhibits release of IL-2 from Lyt-2-positive hybrids incubated with stimulator cells. All Lyt-2-positive hybrids expressed functional surface Lyt-3 encoded by the CTL fusion partner, demonstrating that expression of the Lyt-3 gene is not sensitive to the negative regulation which shuts off the endogenous Lyt-2 gene in hybrids of class I-specific CTLs with the 3B2 or BW5147 cell lines. The existence of inducible T-T cell hybrids expressing functional Lyt-2 and Lyt-3 provides a system for evaluation of the role(s) of Lyt-2 and Lyt-3 in the induction of function independent of cell growth.

Effects of ohmefentanyl on CA1 field potentials in rat hippocampus slices

The effects of ohmefentanyl (OMF), a new opiate agonist with high affinity and high specificity for mu receptors, was examined on CA1 field potentials in the transverse hippocampal slices. OMF showed two effects upon the evoked population spikes (PS) recorded in stratum pyramidale: 1) a concentration-dependent increase in the amplitude of PS, which was largely reversed by naloxone, and 2) production of a naloxone-reversible additional PS at high stimulus intensities. No significant change was seen in field excitatory postsynaptic potential (EPSP) recorded simultaneously in stratum radiatum. The EC50 for OMF and morphine were 6.6 and 3700 nmol.L-1, respectively. Thus OMF was 560 times more potent than morphine. The mechanism of augmentation by OMF of PS could be attributed to disinhibition as judged from the paired-pulse paradigm.

Solubility of calcium salts of unconjugated and conjugated natural bile acids

The approximate solubility products of the calcium salts of ten unconjugated bile acids and several taurine conjugated bile acids were determined. The formation of micelles, gels, and/or precipitates in relation to Ca2+,Na+, and bile salt concentration was summarized by "phase maps." Because the ratio of Ca2+ to bile salt in the precipitates was ca. 1:2, and the activity of Ca2+ but not that of bile salt (BA-) could be measured, the ion product of aCa2+ [BA-]2 was calculated. The ion product (= Ksp) ranged over nine orders of magnitude and the solubility thus ranged over three orders of magnitude; its value depended on the number and orientation of the hydroxyl groups in the bile acid. Ion products (in units of 10(-9) mol/l)3 were as follows: cholic (3 alpha OH,7 alpha OH,12 alpha OH) 640; ursocholic (3 alpha OH,7 beta OH,12 alpha OH) 2300; hyocholic (3 alpha OH,6 alpha OH,7 alpha OH) 11; ursodeoxycholic (3 alpha OH,7 beta OH) 91; chenodeoxycholic (3 alpha OH,7 alpha OH) 10; deoxycholic (3 alpha OH,12 alpha OH) 1.5; 12-epideoxycholic (lagodeoxycholic, 3 alpha OH,12 beta OH) 2.2; hyodeoxycholic (3 alpha OH,6 alpha OH) 0.7; and lithocholic (3 alpha OH) 0.00005. The critical micellization temperature of the sodium salt of murideoxycholic acid (3 alpha OH,6 beta OH) was greater than 100 degrees C, and its Ca2+ salt was likely to be very insoluble. Taurine conjugates were much more soluble than their corresponding unconjugated derivatives: chenodeoxycholyltaurine, 384; deoxycholyltaurine, 117; and cholyltaurine, greater than 10,000. Calcium salts of unconjugated bile acids precipitated rapidly in contrast to those of glycine conjugates which were metastable for months. Thus, hepatic conjugation of bile acids with taurine or glycine not only enhances solubility at acidic pH, but also at Ca2+ ion concentrations present in bile and intestinal content.