Protective effect of the nitric oxide pathway in L-citrulline renal ischaemia-reperfusion injury in rats

To observe the protective effects of L-citrulline on the renal I/R injury and elucidate the mechanisms involved, 48 rats were randomized into eight groups: Group 1: sham operated; Group 2: I/R (45 min renal ischaemia and 24 h reperfusion); Group 3: I/R + L-citrulline (300 mg/kg, i.g.); Group 4: I/R + L-citrulline (600 mg/kg, i.g.); Group 5: I/R + L-citrulline (900 mg/kg, i.g.); Group 6: I/R + normal saline (NS, i.g.); Group 7: I/R + N sup ω nitro-L-arginine ester (L-NAME, 20 mg/kg, i.p.); Group 8: I/R + L-citrulline (900 mg/kg, i.g.) + L-NAME (20 mg/ kg, i.p.). At the end of the reperfusion period, serum was collected and the kidneys underwent histological and biochemical examinations. Our results showed that pre-treatment with L-citrulline (300, 600, and 900 mg/kg) significantly ameliorated the renal injury caused by I/R. Moreover, L-citrulline prevented induction of lipid peroxidation and increased the activity of superoxide dismutase and the levels of glutathione and nitric oxide. The I/R-induced decreases in total nitric oxide synthase activity, inducible nitric oxide activity, constitutive nitric oxide activity and endothelial nitric oxide protein expression in the renal cortex were significantly prevented. However, the L-citrulline-mediated protection was significantly antagonized by co-administration of L-NAME. These results suggested that L-citrulline administration exhibited significant protection against renal I/R injury. This protective effect, at least in part, via up-regulation of the endothelial nitric oxide protein expression and constitutive nitric oxide synthase activity, maintained production of nitric oxide at the basal level.

Role of vegetation in enhancing radon concentration and ion production in the atmosphere

The role of ions in the production of atmospheric particles has gained wide interest due to their profound impact on climate. Away from anthropogenic sources, molecules are ionized by alpha radiation from radon exhaled from the ground and cosmic γ radiation from space. These molecular ions quickly form into "cluster ions", typically smaller than about 1.5 nm. Using our measurements and the published literature, we present evidence to show that cluster ion concentrations in forest areas are consistently higher than outside. Owing to the low range of alpha particles, radon present deep in the ground cannot directly contribute to the measured cluster ion concentrations. We propose an additional mechanism whereby radon, which is water-soluble, is brought up by trees and plants through the uptake of groundwater and released into the atmosphere by transpiration. We estimate that, in a forest comprising eucalyptus trees spaced 4 m apart, trees may account for up to 37% of the radon that is released from the ground during the middle of the day when transpiration rates are high. The corresponding percentage on an annual basis is 4.1%. Considering that 24% of the earth's land area is still covered in forests; these findings have potentially important implications for atmospheric aerosol formation and climate.

Detection of cervical metastatic lymph nodes in papillary thyroid carcinoma by Fourier transform infrared spectroscopy

Background

A previous study demonstrated that Fourier transform infrared (FTIR) spectroscopy can distinguish thyroid cancer from benign thyroid lesions. The aim of this study was to explore the use of FTIR for identifying metastatic lymph nodes of papillary thyroid cancer in vitro, and distinguishing between metastatic and non-metastatic tissue.

Methods

Some 184 freshly removed cervical lymph nodes were obtained from 22 patients with papillary thyroid cancer undergoing thyroid surgery with lymph node dissection. Samples were measured by FTIR spectroscopy before being processed for histopathological diagnosis. The FTIR spectrum of each sample identified 13 bands from 1000 to 4000 cm−1. The peak position, intensity and full width at half maximum of each absorbent band were measured, and the relative intensity ratios were calculated. The FTIR spectra of metastatic lymph nodes were compared with those of non-metastatic nodes, and a linear discriminant analysis was performed based on these data.

Results

Histopathological examination confirmed 61 metastatic and 123 non-metastatic lymph nodes. The FTIR parameters of metastatic and non-metastatic lymph nodes differed owing to the content or configuration alterations of nucleic acids, proteins, lipids and carbohydrates. The sensitivity for FTIR in diagnosing metastatic lymph nodes was 80·3 per cent, the specificity was 91·9 per cent and the accuracy was 88·0 per cent.

Conclusion

FTIR spectroscopy is a novel technique for detection of metastatic lymph nodes and may prove useful in surgery for papillary thyroid cancer.

Preliminary evaluation on the use of homing pigeons as a biomonitor in urban areas

This study evaluates the usefulness of homing pigeons as a biomonitor of polycyclic aromatic hydrocarbons (PAHs) in urban environments. The mean concentrations of total PAHs in liver and lung tissues were greater in pigeons from Beijing compared to pigeons from Chengdu, however, this difference was only statistically significant for PAH concentrations in liver tissue (P < 0.05). Similarly, the severity of anthracosis or pneumoconiosis in lung tissue and hepatitis in liver tissue was greater in pigeons from Beijing compared to pigeons from Chengdu. Low molecular weight PAHs dominated the contribution of individual PAHs in both tissues. Significant differences (P < 0.05) were observed for most low and moderate molecular weights PAHs in liver and for some low and high molecular weights PAHs in lung between the two cites. The profile patterns of individual PAHs were similar between lung tissue of pigeons and between local ambient airs in summer for both cities, whereas the profile patterns between liver tissue and pigeon food were less similar. These data suggest that homing pigeons may be of value as a biomonitor of environmental pollution in urban areas.

Proton irradiation of ultra high molecular weight polyethylene for space applications

The effect of low dose proton irradiation on the morphology of ultra high molecular weight polyethylene (UHMWPE) was studied. The integral proton dose was ranging from 900 Gy to 1200 Gy. The experimental data revealed that low dose proton irradiation in the presence of oxygen leads to the formation of intermolecular crosslinks in UHMWPE and that proton irradiation produces morphological changes that involve a reduction in the thickness of the interfacial region and increase in the thickness of the amorphous region. The observed morphological changes depend on the integral dose

Mesenchymal stem cells selectively engraft into tumor stroma and produce potent antitumor proteins in situ

3025

Background: The formation of stroma is essential for tumor growth and involves complex interactions between malignant cells and non-tumor stromal cells. We have previously demonstrated that IV injected bone marrow derived mesenchymal stem cells (MSC) integrate into solid tumors as stromal elements (Cancer Res 62:3603, 2002; JNCI 96:1593, 2004). Methods: MSC were labeled by a fiber modified Ad vector expressing firefly luciferase (AdLux-F/RGD), injected into normal or tumor-bearing SCID mice, and biodistributed MSC-Lux were imaged utilizing the Xenogen IVIS system. Results: After IP injection, no hMSC-LUX were detected in normal animals after 7 days, while strong punctate regions of LUX-activity were observed in ovarian tumors. Tumor cells transduced with renilla luciferase constructs co- localized with firefly luciferase MSC. Next, we examined whether hMSC-producing interferon-beta (IFNβ-MSC) could inhibit the growth of metastatic tumors in the lungs of SCID mice. When injected IV (4 doses of 106 MSC/week) into SCID mice with pulmonary metastases of carcinomas or melanomas, tumor growth was significantly inhibited as compared with untreated or vector-control MSC controls (p= 0.007). IV injected IFNb-MSC prolonged the survival of mice bearing metastatic breast carcinomas (p=0.001). In an orthotopic, chemoresistant breast cancer model in syngeneic immunocompetent mice, MSC producing IFN-β completely abrograted tumor growth. Localized low-dose XRT to tumors significantly increased the number of tumor-resident MSC. Conclusions: The data suggest that systemically administered gene-modified MSC selectively engraft into the tumor microenvironment and remain resident as part of the tumor architecture. MSC-expressing IFN-β inhibit the growth of melanomas, gliomas, metastatic breast and ovarian cancers in vivo and prolong the survival of mice bearing established tumors. Clinical trials are in preparation.

No significant financial relationships to disclose.

Characterization of the 12C4 survivin monoclonal antibody and insight into the expression of survivin in human adult tissues

AIMS

To elucidate the expression and regulation of survivin in normal tissues.

METHODS AND RESULTS

A novel monoclonal antibody (12C4) to survivin was generated. Application of this antibody to determine survivin expression in human normal adult tissues revealed that most adult tissues do not express survivin and, where it is present, survivin is largely restricted to a small subset of epithelial cells and cells with proliferative potential such as thymus. Survivin expression among positive tissues showed individual variations, ranging from zero to < 5% positive cells in epithelial cell populations. Testis is the only human adult tissue highly expressing survivin, with 60-70% positivity in the nuclei of spermatogonia. Consistent with deregulated expression of survivin associated with oncogenesis, we found that certain ligands and transcription factors differentially modulate survivin promoter activity in cancer cells versus normal/untransformed cells.

CONCLUSION

Deregulation of survivin transcription controls in individual epithelial cells may contribute to oncogenesis in various human adult tissues.

Differential tumor suppressor properties and transforming growth factor-beta responsiveness of p57KIP2 in leukemia cells with aberrant p57KIP2 promoter DNA methylation

To investigate if the tumor suppressor properties of p57KIP2 are dependent on its DNA methylation status, we studied the impact of several stress stimuli in leukemic cell lines with different p57KIP2 promoter DNA methylation levels. p57KIP2 reactivation was observed after stimulation with transforming growth factor-beta, other cytokines, high-density culture or serum withdrawal in p57KIP2 promoter unmethylated cells but not in methylated cells. In these cells, p57KIP2 reactivation required the use of a hypomethylating agent or a histone deacetylase inhibitor. Overexpression of p57KIP2 in p57KIP2 promoter methylated leukemic cell lines resulted in cell growth arrest and the induction of apoptosis. In contrast, overexpression of p57KIP2 in partially methylated cells only resulted in a moderate inhibition of cell growth and had no impact on apoptosis. Transduction of unmethylated cells expressing high levels of p57KIP2 with p57KIP2 short hairpin RNA resulted in increased cell proliferation. These results suggest that the tumor suppressive properties of p57KIP2 in leukemia may depend on the intrinsic promoter DNA methylation status of the gene.

Vaccination with leukemia cells expressing cell-surface-associated GM-CSF blocks leukemia induction in immunocompetent mice

The fundamental basis for immunotherapy of leukemia is that leukemic cells express specific antigens that are not expressed by normal hematopoietic cells. However, the host immune system appears to be tolerant to leukemia cells. To overcome this tolerance, we vaccinated immunocompetent mice with murine leukemia cells (WEHI-3B and BCR-ABL+ 32D cells) transduced with a specifically constructed transmembrane form of granulocyte-macrophage colony-stimulating factor (tmGM-CSF). The transduced cells expressed tmGM-CSF on the cell-surface. To determine whether tmGM-CSF-expressing WEHI-3B leukemia cells would prevent leukemia formation as a vaccine, immunocompetent mice (BALB/c and C3H/HEJ) were immunized with lethally irradiated murine leukemia cells expressing cell-surface tmGM-CSF before challenging mice with murine leukemia cells. Two immunocompetent mouse models were investigated, either WEHI-3B cells in BALB/c mice or BCR-ABL+ 32D cells in C3H/HEJ mouse. The results showed that 100% of WEHI-3B/tmGM-CSF-vaccinated BALB/c mice and about 65% of 32D+ BCR-ABL/tmGM-CSF-vaccinated C3H/HEJ mice were protected from leukemia after leukemia cell challenge, whereas all non-vaccinated mice succumbed to leukemia. Spleen and marrow cell suspensions from vaccinated mice challenged with WEHI-3B cells lacked detectable GFP+ WEHI-3B cells at 82 days post-challenge. A significant delay of death was observed in C3H/HEJ mice challenged with the very aggressive DA-1 cell line expressing BCR-ABL. Vaccination of mice with WEHI-3B/CD40L cells protected 80% of the mice from the WEHI-3B challenge. Notably, 60% of the WEHI-3B/BALB/c mice were also protected from leukemia when WEHI-3B/tmGM-CSF vaccination was carried out after the leukemia challenge. In order to determine whether cellular immunity is involved in this vaccine-mediated protection, either CD4+ or CD8+ T cells were depleted from mice after the WEHI-3B/tmGM-CSF vaccination. The results indicate that CD8+ T-cells mediated the protective immune response provided by the irradiated tmGM-CSF-expressing WEHI-3B cells. In addition, vaccination of nude mice did not provide protection from WEHI-3B leukemia induction. Importantly, 80% of non-vaccinated mice were also protected from a WEHI-3B cell challenge after receiving spleen cells from vaccinated mice 1 day before challenge with leukemia cells. These results indicate that overexpression of tmGM-CSF on the leukemia cell-surface can enhance the recognition of leukemic cells by CD8+ T cells, and can either prevent or significantly delay leukemia induction. These findings suggest that injection of irradiated leukemia cells expressing cell-surface-bound GM-CSF has the potential as an immunological approach to treat leukemia.

Chemical ablation of the gallbladder: clinical application and long-term observations

BACKGROUND

We investigated whether minicholecystostomy followed by chemical ablation of the gallbladder could be used as a alternative to cholecystectomy in patients at high risk for complications of surgery.

METHODS

From January 1990 through January 2003, 34 patients at high risk underwent minicholecystostomy. Six weeks after the operation, microwave irradiation was provided to burn the mucosa of the cystic duct at locations at 3, 6, 9, and 12 o'clock around the orifice. Each location was treated eight times at 50 mA for 10 sec. Then chemical ablation of the gallbladder was performed by infusing 95% ethanol into the gallbladder cavity for 30 min. For each sclerosis course, the procedure was repeated every 4 h for a total of eight times. Approximately 2 weeks later, the drainage tube was removed from the gallbladder after cholecystography showed that no cavity other than the lumen of the tube remained in the gallbladder.

RESULTS

Patients tolerated the procedure well and were followed with ultrasonography for 2-14 years (mean, 9). Twenty-nine patients had no complications or side effects, and five patients developed a 1.5- to 3- cm mucocele in the gallbladder. The long-term success rate of sclerotherapy was 85.3% (29/34). No recurrent cholecystitis, new stone or formation, canceration were encountered at the site of the gallbladder.

CONCLUSIONS

Minicholecystostomy followed by chemical ablation of the gallbladder was a safe, effective, and simple procedure for treating high-risk patients with acute cholecystitis and/or cholelithiasis.

Immunohistochemical distribution and quantitative biochemical detection of advanced glycation end products in fetal to adult rats and in rats with streptozotocin-induced diabetes

SUMMARY

We used immunohistochemical methods and four monoclonal antibodies for specific molecular structures of advanced glycation end products (AGE)-6D12, KNH-30, 1F6, and 2A2-to examine localization of AGE in fetal, young, and adult rats, and rats with streptozotocin-induced diabetes. 6D12 recognized N(epsilon)-(carboxymethyl)lysine (CML); KNH-30, N(epsilon)-(carboxyethyl)lysine (CEL); and 1F6, fluorolink. The epitope of 2A2 is as yet unknown. Immunoreactivities for these monoclonal antibodies were found in various organs and tissues in postnatal and adult rats, and accumulation increased with aging. In the fetuses, AGE structures were detected at 10 fetal days, and their accumulation increased during ontogeny. Reversed-phase high-performance liquid chromatography revealed CML in fetuses at 13 fetal days and in lungs of 28-week-old rats. In various organs and tissues of fetal, young, and adult rats, CML, CEL, 2A2-positive AGE, and fluorolink accumulated, in that order, which suggests that the accumulation of CML, a nonfluorescent/noncross-linked AGE, occurs earlier than accumulation of fluorolink, a fluorescent/cross-linked AGE. In diabetic rats, hepatocytes, splenic macrophages, renal glomerular endothelial and mesangial cells, testicular Leydig cells, and erythrocytes showed excessive accumulation of AGE, leading to the pathologic changes characteristic of diabetes mellitus. For the induction of these changes, persistent hyperglycemia and hyperketonemia might be important for acceleration of intracellular AGE accumulation in diabetic rats. Thus, AGE accumulation in tissues and cells occurs not only during aging and in diabetes mellitus but also from an early stage of ontogeny.

Cephalometric image analysis and measurement for orthognathic surgery

Automatic identification of landmarks in cephalometry is very important and useful for orthognathic surgery. A computerised automatic cephalometric analysis system (CACAS), based on image processing, is presented. For an original X-ray image, median filtering and histogram equalisation are used to improve image quality. The edge of an X-ray image is detected by a wavelet transform and Canny filter. Seventeen landmarks in cephalometry are successfully identified by knowledge-based edge tracing and changeable templates. Seventy-three measurements based on distances, angles and ratios between landmarks are computed automatically. The reliability of the landmarks and the validity of the measurements are compared for automatic and manual operation. The values of measurements obtained by CACAS are more precise and reliable: the mean error for linear measurements is less than 0.9mm; the mean error for angular measurements is less than 1.2 degrees. The rate of validity is over 80%, even if the image quality is poor. For an image with a high signal-to-noise ratio, the rate of validity of landmarking and measurements using the CACAS system is over 90%.

Genetic basis for susceptibility to noise-induced hearing loss in mice

The C57BL/6J (B6) and DBA/2J (D2) inbred strains of mice exhibit an age-related hearing loss (AHL) due to a recessive gene (Ahl) that maps to Chromosome 10. The Ahl gene is also implicated in the susceptibility to noise-induced hearing loss (NIHL). The B6 mice (Ahl/Ahl) are more susceptible to NIHL than the CBA/CaJ (CB) mice (+(Ahl)). The B6xD2.F(1) hybrid mice (Ahl/Ahl) are more susceptible to NIHL than the CBxB6.F(1) mice (+/Ahl) [Erway et al., 1996. Hear. Res. 93, 181-187]. These genetic effects implicate the Ahl gene as contributing to NIHL susceptibility. The present study demonstrates segregation for the putative Ahl gene and mapping of such a gene to Chromosome 10, consistent with other independent mapping of Ahl for AHL in 10 strains of mice [Johnson et al., 2000. Genomics 70, 171-180]. The present study was based on a conventional cross between two inbred strains, CBxB6.F(1) backcrossed to B6 with segregation for the putative +/Ahl:Ahl/Ahl. These backcross progeny were exposed to 110 dB SPL noise for 8 h. All of the progeny were tested for auditory evoked brainstem responses and analyzed for any significant permanent threshold shift of NIHL. Cluster analyses were used to distinguish the two putative genotypes, the least affected with NIHL (+/Ahl) and most affected with PTS (Ahl/Ahl). Approximately 1/2 of the backcross progeny exhibited PTS, particularly at 16 kHz. These mice were genotyped for two D10Mit markers. Quantitative trait loci analyses (log of the odds=15) indicated association of the genetic factor within a few centiMorgan of the best evidence for Ahl [Johnson et al., 2000. Genomics 70, 171-180]. All of the available evidence supports a role for the Ahl gene in both AHL and NIHL among these strains of mice.

The role of reactive nitrogen species in secondary spinal cord injury: formation of nitric oxide, peroxynitrite, and nitrated protein

To determine whether reactive nitrogen species contribute to secondary damage in CNS injury, the time courses of nitric oxide, peroxynitrite, and nitrotyrosine production were measured following impact injury to the rat spinal cord. The concentration of nitric oxide measured by a nitric oxide-selective electrode dramatically increased immediately following injury and then quickly declined. Nitro-L-arginine reduced nitric oxide production. The extracellular concentration of peroxynitrite, measured by perfusing tyrosine through a microdialysis fiber into the cord and quantifying nitrotyrosine in the microdialysates, significantly increased after injury to 3.5 times the basal level, and superoxide dismutase and nitro-L-arginine completely blocked peroxynitrite production. Tyrosine nitration examined immunohistochemically significantly increased at 12 and 24 h postinjury, but not in sham-control sections. Mn(III) tetrakis(4-benzoic acid)-porphyrin (a novel cell-permeable superoxide dismutase mimetic) and nitro-L-arginine significantly reduced the numbers of nitrotyrosine-positive cells. Protein-bound nitrotyrosine was significantly higher in the injured tissue than in the sham-operated controls. These results demonstrate that traumatic injury increases nitric oxide and peroxynitrite production, thereby nitrating tyrosine, including protein-bound tyrosine. Together with our previous report that trauma increases superoxide, our results suggest that reactive nitrogen species cause secondary damage by nitrating protein through the pathway superoxide + nitric oxide peroxynitrite protein nitration.

Glycolaldehyde, a reactive intermediate for advanced glycation end products, plays an important role in the generation of an active ligand for the macrophage scavenger receptor

Long-term incubation of proteins with glucose leads to the formation of advanced glycation end products (AGEs) that are recognized by AGE receptors. Glyoxal, glycolaldehyde (GA), and methylglyoxal are potential intermediates for the formation of AGE structures such as Nomega-(carboxymethyl)lysine (CML). We evaluated the contribution of these aldehydes to the formation of AGE structure(s), particularly the structure important for the receptor-mediated endocytic uptake of AGE proteins by macrophages. GA-modified bovine serum albumin (BSA), methylglyoxal-modified BSA (MG-BSA), and glyoxal-modified BSA (GO-BSA) were prepared, and their physicochemical, immunological, and biologic properties were compared with those of glucose-derived AGE-BSA. CML contents were high in GO-BSA and low in GA-modified BSA (GA-BSA) but did not exist in MG-BSA. The fluorescence patterns of GA-BSA and MG-BSA were similar to those of glucose-derived AGE-BSA but were weak in GO-BSA. Immunochemically, the antibody against non-CML structures of glucose-derived AGE-BSA reacted strongly with GA-BSA and weakly with GO-BSA but did not react with MG-BSA. The negative charge of these ligands increased to a similar extent. However, GA-BSA, but not MG-BSA or GO-BSA, underwent receptor-mediated endocytosis by the macrophage-derived cell line RAW 264.7, which was effectively inhibited by glucose-derived AGE-BSA, acetylated LDL, and oxidized LDL, which are well-known ligands for the macrophage type I and type II class A scavenger receptors (MSR-A). The endocytic uptake of GA-BSA by mouse peritoneal macrophages was also significant, but that by peritoneal macrophages from MSR-A-deficient mice was markedly reduced. Our results suggest that GA serves as an important intermediate for the generation of AGE structure(s) responsible for recognition by MSR-A.

Vertebral fractures in Beijing, China: the Beijing Osteoporosis Project

Women in China have much lower risk of hip fracture than women in Europe or North America but their risk of vertebral fractures is not known. Lateral spine radiographs, hip and lumbar spine bone density, and potential risk factors for and consequences of vertebral fractures were assessed in a random sample of 402 women age 50 years or older living in Beijing, China. The prevalence of vertebral fractures, defined by vertebral morphometry, increased from 5% (95% CI, 1-9%) in 50- to 59-year olds to 37% (27-46%) among women age 80 years or older. The age-standardized prevalence of vertebral fractures was 5.5% lower than found by similar methods for women in Rochester, MN, U.S.A. Each SD lower spine bone mineral density (BMD) was associated with a 2.4-fold (1.7-3.5) increased odds of having a vertebral fracture. Women with a history of heavy physical labor had a lower risk of vertebral fractures. Vertebral fractures were associated with decreased height loss and limited physical function but not chronic back pain. Women in Beijing, China have lower bone density and a slightly lower rate of vertebral fracture than white women in the United States. Low bone density and more sedentary occupations increase the risk of fracture in women living in urban China.

[FT-Raman spectroscopic investigation on stomach cancer]

FT-Raman spectroscopy was used to investigate 40 normal and malignant tissues from stomach. Statistic analysis shows that the bands related to OH, NH, C=O stretching and H-O-H bending are stronger in malignant tissues. This phenomenon suggests that the hydrogen bonding systems among water and protein vary in malignant tissues.

[Preliminary study on the effects of coagulation factor XII on fibrinolysis]

OBJECTIVE

To study the effects of FXII on fibrinolysis in patients with cerebral thrombosis.

METHODS

Plasma level of FXII:C, FXII:Ag, FXIIa and beta FXIIa and fibrinolysis activities were examined by ELISA. Screening of FXII gene mutation by MOEA.

RESULTS

FXII:C in 22 of 107 patients with cerebral thrombosis decreased, which was similar to the feature of FXII cross-reacting material positive (FXII CRM(+)). There were significant increase in plasma levels of PLG:A and alpha(2)AP:A and decrease in D-dimer, moreover, plasma levels of FXIIa and betaFXIIa were lower in patients than in controls. FXII gene mutation was not found in 22 of 107 patients.

CONCLUSION

Decrease of FXII:C may play an important role in cerebral thrombosis by reducing activation of plasminogen. The gene mutation of FXII CRM(+)-like abnormal FXII was different from the known FXII gene mutation. Mutations in the regions of FXII Arg (334) and Arg (353) may be more important for the reducing of FXIIa, beta FXIIa levels and fibrinolysis activities. FXII assay should be included in thrombotic disorder screening.

An immunosuppressive and anti-inflammatory HLA class I-derived peptide binds vascular cell adhesion molecule-1

BACKGROUND

A synthetic peptide corresponding to residues 75-84 of HLA-B2702 modulates immune responses in rodents and humans both in vitro and in vivo.

METHODS

We used a yeast two-hybrid screening, an in vitro biochemical method, and an in vivo animal model.

RESULTS

Two cellular receptors for this novel immunomodulatory peptide were identified using a yeast two-hybrid screen: immunoglobulin binding protein (BiP), a member of the heat shock protein 70 family, and vascular cell adhesion molecule (VCAM)-1. Identification of BiP as a ligand for this peptide confirms earlier biochemical findings, while the interaction with VCAM-1 suggests an alternative mechanism of action. Binding to the B2702 peptide but not to closely related variants was confirmed by ligand Western blot analysis and correlated with immunomodulatory activity of each peptide. In mice, an ovalbumin-induced allergic pulmonary response was blocked by in vivo administration of either the B2702 peptide or anti-VLA-4 antibody.

CONCLUSIONS

We propose that the immunomodulatory effect of the B2702 peptide is caused, in part, by binding to VCAM-1, which then prevents the normal interaction of VCAM-1 with VLA-4.

Proliferating cell nuclear antigen as the cell cycle sensor for an HLA-derived peptide blocking T cell proliferation

Synthetic peptides corresponding to structural regions of HLA molecules are novel immunosuppressive agents. A peptide corresponding to residues 65-79 of the alpha-chain of HLA-DQA03011 (DQ65-79) blocks cell cycle progression from early G1 to the G1 restriction point, which inhibits cyclin-dependent kinase-2 activity and phosphorylation of the retinoblastoma protein. A yeast two-hybrid screen identified proliferating cell nuclear Ag (PCNA) as a cellular ligand for this peptide, whose interaction with PCNA was further confirmed by in vitro biochemistry. Electron microscopy demonstrates that the DQ65-79 peptide enters the cell and colocalizes with PCNA in the T cell nucleus in vivo. Binding of the DQ65-79 peptide to PCNA did not block polymerase delta (pol delta)-dependent DNA replication in vitro. These findings support a key role for PCNA as a sensor of cell cycle progression and reveal an unanticipated function for conserved regions of HLA molecules.

Clinical observation and experimental study on compound hypoglycemic decoction for hyperglycemia

PURPOSE

To observe the clinical efficacy of Compound Hypoglycemic Decoction (CHD) and its effect on serum total cholesterol in model mice.

METHOD

The paired t test was used to analyze the data recorded before and after administration of drugs for hyperglycemia induced by intraperitoneal injection of 75% egg yolk emulsion in experimental mice. CHD and Fenofibrate were administered as prevention measures.

RESULTS

The total effective rate of serum total cholesterol (TC) decrease in 60 cases of hyperglycemia was 86.66% and that of serum total triglyceride (TG) decrease was 81.81%. The total effective rate of high-density lipoprotein-cholesterol (HDL-C) increase was 75%. The decrease in TC and TG, and the increase of HDL-C after treatment by in-group comparison were all significant (P < 0.05). 21.9% and 22.2% decrease in the total cholesterol was respectively found in the CHD and Fenofibrate groups (both P < 0.05), with no significant difference.

CONCLUSION

The hypoglycemic action of Compound Hypoglycemic Decoction was remarkable in clinical practice, and it is very effective in preventing hyperglycemia in experimental mice.

A novel DNA element mediates transcription of Nkx2.1 by Sp1 and Sp3 in pulmonary epithelial cells

NKX2.1 is a member of the NK2 family of homeodomain-containing transcription factors whose targeted disruption in mouse results in the absence of thyroid tissue and a severely abnormal lung phenotype. Little is known regarding the mechanisms that control tissue and temporal specificity of Nkx2.1 gene expression. The Nkx2.1 gene has been cloned from a number of species and it is composed of three exons and two introns. Two distinct DNA domains located 5' of exon I and within intron I have been found to exhibit promoter activity in lung and thyroid cells. In the current study we used deletional analysis of the 5' flanking region of exon I and identified a 300 bp TATA-less region that exhibits significant promoter activity in H441 cells. The DNA sequence of this region contains multiple palindromes, composed of G/C-rich elements. DNase I footprinting demonstrates that this promoter region interacts with nuclear factors present in H441 cells. In particular electrophoretic mobility shift assay using antibodies against the Sp family members show that both Sp1 and Sp3 as well as an as yet unknown H441-specific factor interact with the palindromic structure within this promoter region. Co-transfection studies show that this promoter region responds to Sp1 and Sp3 and mutations therein result in a significantly diminished response to these transcriptional factors. Therefore, we have identified a novel DNA structure on the Nkx2.1 gene which participates in transcription of this gene in pulmonary epithelial cells by Sp1 and Sp3 transcription factors.