The role of tumor necrosis factor signaling pathways in the response of murine brain to irradiation

Late effects after radiotherapy for brain tumors can be severe and tend to limit the efficacy of this treatment modality. The mechanisms governing the development of late radiation-induced lesions in the brain are not clear, but they are preceded by cycles of molecular and cellular events including production of cytokines, one of which is tumor necrosis factor (TNF)-alpha. There is literature to support possible roles for TNF-alpha as a contributor to edema, gliosis, and demyelination in the brain, all of which are histopathologically associated with radiation-induced brain damage. We have examined the role of TNF-alpha signaling in the response to brain irradiation using TNFRp55- or TNFRp75-deficient and control mice. Mice lacking TNFRp75 exhibited increased early radiation-induced apoptosis in putative stem cell regions of the brain. At 1 month, they had decreased proliferative responses in the same regions, and by 3 months they were demonstrating dose-dependent seizures and other severe neurological abnormalities that were not seen in control or TNFRp55-/- mice. Seizure activity correlated with the onset of extensive demyelination, and by 6 months, levels of myelin basic protein in irradiated TNFRp75-/- mice were approximately 40% of those seen in the other two strains; the animals were moribund and had to be euthanized. These observations indicate that radiation-induced TNF-alpha, acting through TNFRp75, protects against the development of late complications of brain irradiation.

Determination of propranolol concentration in small volume of rat plasma by HPLC with fluorometric detection

A simple, rapid and sensitive fluorescence high performance liquid chromatographic method was developed to determine propranolol concentration in the small volume of rat plasma without the solvent extraction step using pronethanol as the internal standard. The analysis was accomplished using a 5 microm CAPCELL PAK analytical cyano column at room temperature and a mobile phase consisted of 1% aqueous acetic acid containing 0.2% triethylamine and acetonitrile (65:35, v/v; pH 3.8). The flow-rate was kept at 0.5 mL/min and column effluent was monitored with a fluorescence detector at an excitation wavelength of 230 nm and an emission wavelength of 340 nm. Retention times for pronethalol and propranolol were 8.5 min and 10.5 min, respectively. Linear regressions for the standard curves were linear in the range 2-800 ng/mL, giving correlation coefficients above 0.998. The detection limit was 1.34 ng/mL. No analytical interference was observed from endogenous components in rat plasma. This simple and sensitive assay method was feasibly applied to the pharmacokinetic study of propranolol after intravenous administration of 2 mg/kg of propranolol to normal and carbon tetrachloride-induced liver cirrhotic rats.

Urinary N-acetyl-beta-D-glucosaminidase and malondialdehyde as a markers of renal damage in burned patients

This study was aimed to evaluate renal dysfunction during three weeks after the burn injuries in 12 patients admitted to the Hallym University Hankang Medical Center with flame burn injuries (total body surface area, 20-40%). Parameters assessed included 24-hr urine volume, blood urea nitrogen, serum creatinine, creatinine clearance, total urinary protein, urinary microalbumin, 24-hr urinary N-acetyl-beta-D-glucosaminidase (NAG) activity, and urinary malondialdehyde (MDA). Statistical analysis was performed using repeated measures ANOVA test. The 24-hr urine volume, creatinine clearance, and urinary protein significantly increased on day 3 post-burn and fell thereafter. The urine microalbumin excretion showed two peak levels on day 0 post-burn and day 3. The 24-hr urinary NAG activity significantly increased to its maximal level on day 7 post-burn and gradually fell thereafter. The urinary MDA progressively increased during 3 weeks after the burn injury. Despite recovery of general renal function through an intensive care of burn injury, renal tubular damage and lipid peroxidation of the renal tissue suggested to persist during three weeks after the burn. Therefore, a close monitoring and intensive management of renal dysfunction is necessary to prevent burn-induced acute renal failure as well as to lower mortality in patients with major burns.

Can short-term administration of dexamethasone abrogate radiation-induced acute cytokine gene response in lung and modify subsequent molecular responses?

PURPOSE

To investigate the effects of short-term administration of dexamethasone (DEX) on radiation-induced responses in the mouse lung, focusing on expression of pro-inflammatory cytokine and related genes.

METHODS AND MATERIALS

At indicated times after thoracic irradiation and/or drug treatment, mRNA expression levels of cytokines (mTNF-alpha, mIL-1 alpha, mIL-1 beta, mIL-2, mIL-3, mIL-4, mIL-5, mIL-6, mIFN-gamma) and related genes in the lungs of C3H/HeN mice were measured by RNase protection assay.

RESULTS

Radiation-induced pro-inflammatory cytokine mRNA expression levels in lung peak at 6 h after thoracic irradiation. DEX (5 mg/kg) suppresses both basal cytokine mRNA levels and this early response when given immediately after irradiation. However, by 24 h, in mice treated with DEX alone or DEX plus radiation, there was a strong rebound effect that lasted up to 3 days. Modification of the early radiation-induced response by DEX did not change the second wave of cytokine gene expression in the lung that occurs at 1 to 2 weeks, suggesting that early cytokine gene induction might not determine subsequent molecular events. A single dose of DEX attenuated, but did not completely suppress, increases in cytokine mRNA levels induced by lipopolysaccharide (2.5 mg/kg) treatment, but, unlike with radiation, no significant rebound effect was seen. Five days of dexamethasone treatment in the pneumonitic phase also inhibited pro-inflammatory cytokine gene expression and, again, there was a rebound effect after withdrawal of the drug.

CONCLUSIONS

Our findings suggest that short-term use of dexamethasone can temporarily suppress radiation-induced pro-inflammatory cytokine gene expression, but there may be a rebound after drug withdrawal and the drug does little to change the essence and course of the pneumonitic process.

An experimental model of ischemia in rabbit hindlimb

This study was performed to establish an experimental model of ischemia for the investigation of new treatment modality of limb-threatening ischemia. We produced ischemia in the hindlimbs of 8 New Zealand white rabbits. Under general anesthesia, the left femoral artery was exposed, freed, and excised from distal external iliac artery to proximal popliteal and saphenous arteries. And then both hindlimbs were serially examined to assess the ischemia according to the time table until postoperative 6 weeks. We assessed clinical observation, blood pressure, radioisotopic perfusion scan, and angiography. Clinical ischemic changes of the operated feet were observed in 63%. The blood pressure of left calves was measurable on postoperative day 3 (p<0.05, vs preoperative day 2) and then gradually increased to reach a plateau in postoperative week 6. Radioisotopic arterial perfusion showed similar profiles as in blood pressure. Angiography of ischemic hindlimbs demonstrated a few collateral vessels arising from the internal iliac artery with the reconstitution of the posterior tibial artery in postoperative week 2. In postoperative week 6, collaterals remained the same in number. However, these became dilated and tortuous and showed reconstitution in distal hindleg. In conclusion, this is a reproducible, measurable, and economical animal model of hind limb ischemia.

Isolated paraaortic lymph node recurrence after definitive irradiation for cervical carcinoma

PURPOSE

To evaluate the clinical features of isolated paraaortic lymph node (PALN) recurrence after definitive radiotherapy, and analyze the prognostic factors and effect of salvage treatment.

METHODS AND MATERIALS

Of a total 876 patients who received pelvic radiotherapy after the diagnosis of primary cervical carcinoma, 26 were found to have isolated PALN recurrence as the first recurrent site, and these patients enrolled in this study. Only those with primary-site carcinoma controlled and who were free of other distant metastases were eligible. Nineteen of the 26 patients accepted salvage therapy. Fourteen patients accepted concurrent chemoradiation (CCRT), 1 accepted radiation to the paraaortic region, and 4 accepted chemotherapy alone. Clinical parameters evaluated included tumor markers (SCC and CEA) and image studies.

RESULTS

Seven of the 26 patients were alive and disease-free. All 7 survivors had salvage treatment with radiation to the paraaortic region and concurrent cisplatin-based chemotherapy. None of the patients receiving chemotherapy or radiation alone enjoyed long-term, disease-free survival. The 5-year survival rate for isolated PALN recurrence of the 14 patients who accepted salvage concurrent chemoradiation (CCRT) was 51.2%. The presence of a clinical symptom at the time of PALN recurrence was analyzed. Seven of the 12 asymptomatic patients and none of the 14 symptomatic patients survived without disease after salvage treatment. The SCC levels at recurrence showed a statistically significant relationship to disease-free survival.

CONCLUSIONS

An SCC level of < or = 4 ng/ml and a lack of symptoms at the time of recurrence were good prognostic factors in isolated PALN recurrence after primary radiation therapy. In addition to concurrent CCRT, periodical surveillance with tumor markers and imaging studies allowed early detection and salvage of those patients.

Diagnostic efficacy of fluorescence cystoscopy for detection of urothelial neoplasms

BACKGROUND AND PURPOSE

A major problem diagnosing bladder cancer using conventional white-light cystoscopy is that flat and tiny papillary neoplasms can be overlooked. Fluorescence cystoscopy is based on the detection of protoporphyrin IX (PpIX)-induced fluorescence in urothelial neoplasms through the topical administration of 5-aminolevulinic acid (ALA). The diagnostic efficacy of fluorescence cystoscopy in urothelial neoplasms was evaluated in this study. The focus of this investigation was to ascertain whether fluorescence cystoscopy could make a major contribution to staging and improving the choice of adjuvant therapy after transurethral resection.

PATIENTS AND METHODS

A series of 62 patients with suspected bladder cancer were investigated by fluorescence cystoscopy. An intravesical instillation of ALA was conducted 2 hours prior to fluorescence. A total of 274 tissue samples were obtained from the fluorescing and nonfluorescing areas of the bladder.

RESULTS

The sensitivity and negative predictive value of fluorescence cystoscopy were 98.0% and 94.7%, respectively, but the specificity was low (42.9%). Among a total of 148 lesions of urothelial neoplasm, 58 foci (dysplasia in 5, carcinoma in situ in 19, stage Ta in 15, T1 in 15, above T2 in 4) that were invisible under white-light cystoscopy were detected by fluorescence cystoscopy. The final histopathologic status was changed in 45% of patients (28/62) according to this technique. Among these patients, eight (13%) needed additional therapy, including a radical cystectomy in one patient and intravesical therapy in 10.

CONCLUSIONS

The ALA-based fluorescence cystoscopy technique is a safe and simple procedure that enhances the detection of flat and papillary urothelial neoplasms. Moreover, it will be able to provide useful information that will enable proper staging and appropriate further treatment.

Serum after partial hepatectomy stimulates iNOS gene transcription via downstream NF-kappa B site

It has been known that the expression of inducible nitric oxide synthase (iNOS) is up-regulated during hepatic regeneration. The present study characterized the molecular mechanisms involved in the transcriptional activation of iNOS gene by using the serum after partial hepatectomy (post-PH serum) in vitro. The post-PH serum rapidly induced iNOS mRNA expression, which was blocked by anti-tumor necrosis factor-alpha (TNF-alpha) antibody in BNL CL.2 cells, murine embryonic liver cell line. In addition, EMSAs using a NF-kappa B-specific oligomer showed that the up-regulated iNOS mRNA expression in cells treated with post-PH serum correlated with transient activation of NF-kappa B complex (p50/p65 heterodimer). Transient transfection of BNL CL.2 cells with iNOS promoter linked to a CAT reporter gene showed the transcriptional activation of iNOS promoter by post-PH serum. Furthermore, site-directed mutational analysis of the two NF-kappa B sites individually or in combination revealed that iNOS expression by post-PH serum is regulated by the downstream NF-kappa B site, but not by upstream NF-kappa B site. Taken together, these results suggest that the downstream NF-kappa B site acts as an essential component for the iNOS expression by post-PH serum during hepatic regeneration.

Synthesis and antiviral activity of novel exomethylene cyclopropyl nucleosides

Novel cyclopropyl nucleosides were synthesized as potential antiviral agents. The key intermediate 5, prepared from Feist's acid 1 was condensed with purine derivatives by the SN2 type reaction. All the synthesized compounds were evaluated for antiviral activity.

Synthesis and antiviral activity of fluoro-substituted apio dideoxynucleosides

Novel fluoro-substituted apio dideoxynucleosides ((+/-)-3a and (+/-)-3b) were efficiently synthesized starting from 1,3-dihydroxyacetone via Horner-Emmons olefination as a key step. Cyclization of fluoro ester (+/-)-6 under acidic conditions to the fluorolactone was smoothly proceeded in favor of trans-fluorolactone due to the favorable transition state with equatorial hydroxymethyl substituent. Unfortunately, the final nucleosides (+/-)-3a and (+/-)-3b were found to be inactive against several viruses such as HIV-1, HSV-1, HSV-2 and HCMV.

Structure-activity relationships of apio nucleosides as potential antiviral agents

Several types of novel apio nucleosides were synthesized starting from 1,3-dihydroxyacetone and evaluated for antiviral activity. Among compounds tested, amino substituted apio dideoxynucleosides exhibited anti-HBV activity, while thioapio dideoxynucleosides were found to be active against HIV-1. Apio dideoxydidehydro nucleosides showed moderate to potent anti-HCMV activity, but their bioisosteric thioapio dideoxydidehydro nucleosides did not exhibit any significant antiviral activity.

Increased expression of atrial natriuretic peptide in the kidney of rats with bilateral ureteral obstruction

BACKGROUND

Whether the postobstructive diuresis can be related to an altered regulation of local atrial natriuretic peptide (ANP) in the kidney was investigated.

METHODS

Three groups of rats had both of their ureters obstructed for 48 hours. The kidneys were taken without releasing the obstruction in one group [bilateral ureteral obstruction (BUO)]. The obstruction was released in the other two groups and the animals were kept for 4 and 24 hours thereafter to collect urinary data (BUR-4 and BUR-24, respectively). Plasma and urine ANP levels were measured by radioimmunoassay. The mRNA expression of ANP, natriuretic peptide receptor-A (NPR-A), and NPR-C was determined by reverse transcription-polymerase chain reaction. ANP receptors were also quantitated by in vitro autoradiography. The activity of guanylyl cyclase was determined by the amount of cGMP generated in response to ANP.

RESULTS

Urinary volume and sodium excretion increased in BUR-4, along with the ANP mRNA expression in the kidney and the urinary ANP excretion. The ANP excretion positively correlated with the urinary volume and sodium excretion. The mRNA expression of both NPR-A and NPR-C was decreased by BUO, the latter being far more prominently affected. The maximal binding capacity of radiolabeled ANP was decreased in the glomerulus and papilla in BUO. Not only the urinary parameters but also the mRNA expression of ANP, NPR-A, and NPR-C were comparable between BUR-24 and control rats. ANP-stimulated cGMP generation was reduced in the glomerulus and papilla in BUO animals, which was rapidly resumed following the release of the obstruction.

CONCLUSIONS

Postobstructive diuresis may be due partially to an increased ANP activity in the kidney.

Presence of Epstein-Barr virus latent membrane protein 1 gene in the nasopharyngeal swabs from patients with nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck malignancy in southeastern China and Taiwan. Early detection of the local disease followed immediately by proper treatment is essential to increase the cure and survival rates. Because every NPC tumor cell carries Epstein-Barr Virus (EBV) genomes, detection of EBV genomic DNA such as latent membrane protein 1 gene (LMP1) might indicate the presence of NPC. We developed a simple and noninvasive technique of nasopharyngeal swabbing to acquire nasopharyngeal cells for detecting the presence of EBV genome. The aim of this study was to investigate the feasibility and reliability of this technique.

METHODS

We collected nasopharyngeal cells by means of a nasopharyngeal swabbing technique and detected the presence of EBV LMP1 with polymerase chain reaction (PCR). Thirty-eight swab specimens were obtained from patients with NPC who were newly diagnosed or were just beginning radiotherapy. Two groups of control subjects were recruited, including 20 patients with other head and neck cancers and eight family members of the NPC patients. An additional group of 65 NPC patients were enrolled in the course of regular follow-up after definitive radiotherapy.

RESULTS

All of the samples yielded sufficient DNA for PCR amplification. Thirty-six of 38 NPC swab samples were positive for EBV LMP1, and all the control subjects had swab sample results negative for EBV. All five patients with suspected local recurrence exhibited positive EBV test results.

CONCLUSIONS

Demonstration of EBV LMP1 in the nasopharyngeal swab specimens detected NPC with a sensitivity of 94.7% and specificity of 100%. This study confirms the reliability and feasibility of nasopharyngeal swab in the predicting and screening of NPC.

Enhancement of lysophosphatidic acid-induced ERK phosphorylation by phospholipase D1 via the formation of phosphatidic acid

We made stable cell lines overexpressing PLD1 (GP-PLD1) from GP+envAm12 cell, a derivative of NIH 3T3 cell. PLD1 activity and extracellular signal-regulated kinase (ERK) phosphorylation were enhanced in GP-PLD1 cells by the treatment of lysophosphatidic acid (LPA). In contrast, these LPA-induced effects were attenuated with the pretreatment of pertussis toxin (PTX) or protein kinase C (PKC) inhibitor. Moreover, accumulation of phosphatidic acid (PA), a product of PLD action, potentiated the LPA-induced ERK activation in GP-PLD1 cells while blocking of PA production with the treatment of 1-butanol attenuated LPA-induced ERK phosphorylation. From these results, we suggest that LPA activate PLD1 through pertussis toxin-sensitive G protein and PKC-dependent pathways, then PA produced from PLD1 activation facilitate ERK phosphorylation.

Syntheses and structure--activity relationships of novel apio and thioapio dideoxydidehydronucleosides as anti-HCMV agents

On the basis of the fact that apio dideoxynucleosides, in which the furanose oxygen and the C2 of the 2,3-dideoxyribose are transposed, exhibited potent anti-HIV activity and 2',3'-dideoxy-2',3'-didehydronucleosides also showed potent anti-HIV activity, we synthesized apio dideoxydidehydronucleosides in which the oxygen atom and the double bond of the 2,3-dideoxy-2,3-didehydroribose are exchanged. The thioapio dideoxydidehydronucleosides were also synthesized since sulfur serves as a bioisostere of oxygen. Apio dideoxydidehydronucleosides 13a--f were synthesized starting from 1,3-dihydroxyacetone, utilizing phenylselenenyl chemistry as a key step. The ratio of the anomeric mixture was variable from 1:1 to 5:1 during the condensation of nucleosidic bases with the phenylselenyl acetate 11 in the presence of a Lewis acid. This is in contrast with other glycosyl donors such as 5-O-(tert-butyldiphenylsilyl)-2-phenylselenenyl-2,3-dideoxyribosyl acetate which shows excellent neighboring group effect (alpha:beta = 1:99). Thioapio dideoxydidehydronucleosides 22a,b were synthesized from the lactone 9 via thiolactone 17 as a key intermediate which was synthesized from dicyclohexylcarbodiimide coupling of the mercapto acid produced from the basic hydrolysis of thioacetate 16. The majority of apio analogues synthesized in this study exhibited moderate to potent anti-HCMV activity, among which the 5-fluorouracil derivative 13c was found to be the most potent against HCMV, while thioapio analogues showed no activity against HCMV. However, all synthesized compounds did not exhibit any significant activities against HIV-1, HSV-1, and HSV-2. The fact that apio dideoxydidehydronucleosides were active against HCMV suggests that the apio dideoxydidehydro sugar moiety can serve as a novel template for the development of new antiviral agents.

Synthesis and antiviral activity of novel methylene cyclopropyl nucleosides

Novel exomethylene cyclopropyl nucleosides were synthesized as potential antiviral agents. The key intermediate 5 was synthesized in 4 steps, from Feists acid 1 and was condensed with purine derivatives by the SN2 type reaction to give some cyclopropyl nucleosides. The synthesized nucleosides did not showed any significant antiviral activity against HSV-1, HSV-2, HCMV, HIV-1, HIV-2, and HBV up to 100 microM.

Mechanisms mediating the effects of IL-3 gene expression on tumor growth

IL-3 gene expression within tumors leads to host-cell infiltration, particularly by macrophages, slower tumor growth, and enhanced immunogenicity. Surprisingly, tumor-associated macrophages (TAMs) from within FSAN-JmIL3 tumors had decreased expression of TNF-alpha and iNOS. On short-term culture, TAMs from FSAN-JmIL3 tumors regained their capacity to produce TNF-alpha and NO, indicating that they were primed in vivo. In vitro experiments were unable to demonstrate differences between FSAN-JmIL3 and FSAN tumor cells in their ability to stimulate TNF-alpha production by TAMs. In the absence of evidence that TAM activation was responsible for the slower growth of FSAN-JmIL3 tumors, the response of tumor cells to these effector molecules was studied. TNF-alpha and NO were cytotoxic for FSAN-JmIL3 cells but growth stimulatory for FSAN. These tumor-related phenotypic changes may contribute as much if not more than functional changes in host infiltrating cells to the slower growth of FSAN-JmIL3 tumors in vivo.

Regulation of phospholipase D2 by H(2)O(2) in PC12 cells

Phospholipase D2 (PLD2) is expressed in brain and inhibited by synuclein, which is involved in Parkinson's and Alzheimer's diseases. However, the activation mechanism of PLD2 in neuronal cells has not been defined clearly. Hydrogen peroxide (H(2)O(2)) plays roles in the neurodegenerative diseases and also acts as a second messenger of various molecules such as nerve growth factor. To study regulation mechanisms of PLD2 by H(2)O(2) in neuronal cells, we have made stable PC12 cell lines expressing PLD2 (PLD2-PC12 cells). H(2)O(2) treatment stimulated PLD activity in PLD2-PC12 cells in a dose- and time-dependent manner. This activation was inhibited by the treatment with protein kinase C (PKC) inhibitors or by depletion of PKCalpha, -delta, and -epsilon. Phorbol ester markedly activated PLD2. Co-treatment with phorbol ester and H(2)O(2) did not show an additive effect. Chelation of extracellular calcium substantially blocked the H(2)O(2)-induced activation of PLD2. A calcium ionophore induced PLD2 activation in a PKC-dependent manner. Protein-tyrosine kinase inhibitors inhibited H(2)O(2)-induced PLD activation slightly. These data indicate that H(2)O(2) can activate PLD2 in PC12 cells and that this activation is largely dependent on PKC and Ca(2+) ions and minimally dependent on tyrosine phosphorylation.

Transcription of Epstein-Barr virus-encoded nuclear antigen 1 promoter Qp is repressed by transforming growth factor-beta via Smad4 binding element in human BL cells

In Epstein-Barr virus (EBV)-infected BL cells, the oncogenic EBV-encoded nuclear antigen 1 (EBNA 1) gene is directed from the latent promoter Qp. Yeast one-hybrid screen analysis using the -50 to -37 sequence of Qp as the bait was carried out to identify transcriptional factors that may control Qp activity. Results showed that Smad4 binds the -50 to -37 sequence of Qp, indicating that this promoter is potentially regulated by TGF-beta. The association of Smad4 with Qp was further confirmed by supershift of EMSA complexes using Smad4-specific antibody. The transfection of a Qp reporter construct in two EBV(+) BL cell lines, Rael and WW2, showed that Qp activity is repressed in response to the TGF-beta treatment. This repression involves the interaction of a Smad3/Smad4 complex and the transcriptional repressor TGIF, as determined by cotransfection assay and coimmunoprecipitation analysis. Results suggest that TGF-beta may transcriptionally repress Qp through the Smad4-binding site in human BL cells.

Potentiation of early necrotic death of glucose-starved pheochromocytoma 12 cells by nerve growth factor

Recently suggested is an arguable hypothesis that neurotrophins can induce necrosis but suppress apoptosis of target cells in some pathological conditions. We examined this hypothesis by tracing the type of NGF-promoted cell death occurring in a hypoglycemic condition at various angles, such as kinetic analyses, histological examinations of membrane alterations, morphological observations in ultra-structural changes, and determinations of DNA fragmentation. Glucose-starved cell death consisted of two kinetically different stages, suggesting that it be mixed with early and delayed death. Several lines of evidence revealed that NGF prominently enhanced the early death with necrotic characters. By contrast, apoptotic characters of glucose-starved delayed death were not much affected by NGF. Nifedipine, a voltage-gated calcium channel blocker, could completely compensate for the enhancement of the early glucose-starved death by NGF. Interestingly, the NGF-promoted cell death was also blocked by cycloheximide that did not keep PC12 cells alive from glucose starvation. Therefore, all the data in this study suggest that NGF accelerates the early necrosis of glucose-starved cell death probably through the alterations of intracellular calcium ions and protein syntheses.

Synthesis of novel 3'-C-methyl-apionucleosides: an asymmetric construction of a quaternary carbon by Claisen rearrangement

The synthesis of 2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-D-glycero-tetrofuranosyl++ + nucleosides was accomplished in high enatiomeric purity (98.5% ee) via [3,3]-sigmatropic Claisen rearrangement of (E)(S)-5-benzyloxy-1-tert-butyldimethylsilanyloxy-4-methyl-pent-3- en-2-ol prepared from 2,3-O-isopropylidene-D-glyceraldehyde. The synthesized nucleosides were assayed against human immunodeficiency virus (HIV) and hepatitis B virus in human peripheral blood mononuclear (PBM) and 2.2.15 cells, respectively. 6-Amino-9-[2,3-dideoxy-3-C-(hydroxymethyl)-3-C-methyl-beta-D-glycero- tetrofuranosyl]-2-fluoropurine shows moderate antiviral activity (EC50 = 2.55 microM) against HIV-1 strains and 6-amino-9-[3-deoxy-3-C-(hydroxymethyl)-3-methyl-alpha-D-glycero-tetro furanosyl]-2-fluoropurine exhibits potent anti-HIV activity (EC50 = 0.073 microM) with significant cytotoxicity (IC50 = 1.0 microM).

Tumour necrosis factor-alpha and interferon-gamma synergistically activate the RANTES promoter through nuclear factor kappaB and interferon regulatory factor 1 (IRF-1) transcription factors

Inflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) synergistically activate expression of the RANTES (regulated upon activation, normal T-cell expressed and secreted) gene, which plays a crucial role in the chemoattraction of leukocytes during the inflammatory response. To understand at the molecular level the mechanism by which the two cytokines activate RANTES gene expression, we determined the requirement of cis-acting elements in the RANTES promoter and trans-acting factors. The murine RANTES promoter contained one putative interferon regulatory factor, IRF, and three putative nuclear factor kappaB (NF-kappaB) binding sites. Specific destruction of the IRF binding site and one of the three NF-kappaB binding sites abolished the inducibility of promoter activity by IFN-gamma and TNF-alpha, respectively. In contrast, mutation of the other two putative NF-kappaB binding sites did not affect RANTES promoter activity significantly. In addition, the RANTES promoter was stimulated by co-transfection of plasmids that expressed either p65, an NF-kappaB family protein, or the IRF-1 transcription factor. RANTES promoters with mutations in the NF-kappaB or IRF binding sites were not stimulated by p65 or IRF-1 expression, respectively. In electrophoretic mobility-shift and immunologic assays, we showed that IRF-1 was induced after cells were treated with IFN-gamma and that NF-kappaB was activated by TNF-alpha treatment. These results demonstrate that both NF-kappaB and IRF-1 transcription factors mediate the induction of RANTES expression via their cognate cis-acting elements when cells are stimulated by TNF-alpha and IFN-gamma.

Combining radiation therapy with interleukin-3 gene immunotherapy

The goal of this study was to explore immunological strategies to increase local and systemic tumor control in patients receiving radiation therapy. In previous studies, interleukin-3 (IL-3) gene expression within murine tumors was shown to increase their response to irradiation through immune mechanisms. In this study, the efficacy of systemically administered IL-3 gene-transduced irradiated tumor cell vaccines was tested for their ability to augment radiation responses against established immunogenic (FSAR) and nonimmunogenic (FSAN) tumors. Vaccines of irradiated FSAR/FSAN or FSAN-JmIL-3/FSAR-JmIL-3 cells were given intraperitoneally just before and after local irradiation of parental tumors with diameters of 8 mm, as well as in two booster doses. The IL-3 gene-transduced tumor cell vaccines were more effective than the parental vaccines at delaying tumor growth after irradiation, although no complete cures resulted. Responses were largely specific to the tumor type, indicating that tumor-specific immunity was enhanced by IL-3 vaccine administration. When the experiment was repeated in the C3H/HeJ mice, which are deficient in tumor necrosis factor-alpha production, the vaccines were still effective, but less so than in C3H/HeN mice. Systemic IL-3 vaccine treatment increased intratumoral levels of intercellular adhesion molecule-1, Mac-1, EB22/5.3, tumor necrosis factor-alpha, and IL-1 mRNA in irradiated tumors, indicating that cellular infiltration was part of the response. The study demonstrates that local radiation therapy can enhance the efficacy of genetically altered vaccine-based immunotherapy for cancer by decreasing tumor burden. At the same time, tumor cell vaccines may improve the cure rate of local radiation therapy by eliminating residual cancer cells. Although less effective than intratumoral gene expression, administration of IL-3 gene-transduced tumor cell vaccines is clinically a more feasible strategy that may be useful in situations in which the tumor load is small.

Second malignant tumors in patients with nasopharyngeal carcinoma and their association with Epstein-Barr virus

Since previous published studies about second malignant tumors (SMTs) in nasopharyngeal carcinoma (NPC) patients usually included a limited sample size and did not attain consistent results, we conducted a large retrospective study in a cohort of 1,549 patients to assess the risk of SMT in NPC patients following radiotherapy (RT) in Taiwan. The follow-up period ranged from 2 to 16 years, with a median of 7 years. Thirty-nine patients developed SMTs during the 7,145 person-year follow-up [standardized incidence ratio (SIR): 2. 8; 95% confidence interval (CI): 2.0 to 3.9]. Increased risks of developing SMTs were observed for head and neck (H/N) cancer (SIR: 16.5; 95% CI: 10.0 to 26.8), gastric cancer (SIR: 5.5; 95% CI: 2.2 to 11.4) and leukemia (SIR: 9; 95% CI: 1.9 to 26.3). Paraffin-embedded specimens of secondary H/N cancer (11), secondary gastric cancer (6) and their corresponding NPC specimens were examined by EBER in situ hybridization to assess the association between Epstein-Barr virus (EBV) and these SMTs. Twenty-six primary H/N and 5 gastric cancer specimens were chosen as the control groups. In H/N cancer, EBV was detected in 3.8% of the primary cancers and 9.1% of the secondary cancers. All the positive specimens resulted from hypopharyngeal cancer. Of the secondary gastric cancers, only 1 case (16.6%) was associated with EBV. None of the primary gastric cancers was associated with EBV. Our results indicate an increased risk of developing SMTs, with a preference for head and neck cancer, gastric cancer and leukemia, in NPC patients after RT in Taiwan. Only a small proportion of the secondary H/N and gastric cancers was associated with EBV.

Poroelastic properties of bovine vertebral trabecular bone

The theory of poroelasticity has been used to study bone mechanics without directly measuring poroelastic properties. In this study, we developed an experimental protocol and measured the poroelastic properties of bovine vertebral trabecular bone. Mean (+/-SD) values for drained shear modulus, drained Poisson's ratio, undrained Poisson's ratio, Skempton's coefficient, and permeability coefficient were, respectively, 90.85 (+/-59.59) MPa and 0.242 (+/-0.099), 0.399 (+/-0.083), 0.851 (+/-0.144), and 16.31 (+/-8.02) x 10(-8) m2/Pa/sec, respectively. The experimental protocol can be used generally for the measurement of poroelastic properties of bone when cylindrical specimens are available. Measured poroelastic properties can be used directly or converted to Biot's coefficient and modulus, without assuming the incompressibility of solid and fluid constituents, for the poroelastic modeling of bone.