Epidemiological classification of infectious bronchitis virus isolated in Korea between 1986 and 1997

Forty Korean isolates and four reference strains of infectious bronchitis virus (IBV) were classified by reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. Each Korean isolate was isolated from different types of commercial chicken flocks between 1986 and 1997. RFLP patterns of an amplified DNA fragment (1722 bp) containing the S1 gene of IBV digested by restriction enzyme HaeIII showed that the 40 Korean isolates were classified into five genotypes, I to V. Six of them belonged to genotype I which had the same HaeIII and XcmI cleavage patterns with Massachusetts type (H120 and M41) but the other four genotypes had a different HaeIII cleavage pattern from the four reference IBV strains used in this study. Genotype III seemed to be the major type as 29 of the 40 isolates belonged to this type which was consistently found in the chicken flocks since 1990. On the other hand, genotypes II, IV and V were found in the field only in 1986, 1995 and 1995, respectively. Five isolates selected from each of the five genotypes were inoculated into 1-day-old specific-pathogen-free chicks to evaluate their pathogenicity. Genotype III induced 50% mortality as well as severe renal urate deposition on the kidneys but the other four genotypes only showed respiratory distress at 1 to 2 days after inoculation. Live H120 vaccine protected chicks against challenge with isolates selected from genotype I, but not genotypes IV to V. A live KM91p120 strain selected from major genotype III did protect chicks against challenge with isolates from genotype III, in addition to other genotypes, including two recent isolates of genotypes IV and V.

Roles of ultrasonography and computed tomography in the surgical management of cervical lymph node metastases in papillary thyroid carcinoma

AIMS

Adequate evaluation and surgical management of cervical lymph node metastasis is very important in papillary thyroid carcinoma (PTC). The aim of this study was to evaluate the impact of preoperative ultrasonography (US) and computed tomography (CT) on the surgical management of cervical lymph node metastases in PTC.

METHODS

Medical records and imaging findings were retrospectively analyzed for 252 patients with PTC who underwent thyroidectomy with neck dissection.

RESULTS

The sensitivity of both imaging techniques was lower in the central neck (US 23%, CT 41%) than in the lateral neck (US 70%, CT 82%). The specificities of US and CT were 97% and 90% in the central neck, and 84% and 64% in the lateral neck, respectively. Our surgical plans for therapeutic neck dissection were based on imaging findings in 59% of patients who underwent lateral compartment neck dissection and in 32.1% of patients who underwent central compartment neck dissection, respectively.

CONCLUSIONS

The roles of preoperative US and CT in surgical planning for central compartment neck dissection in PTC are limited because of their low sensitivity in the central neck, but US and CT may be useful in cases with non-palpable lateral neck nodes.

Early bloodstream infection after pediatric living donor living transplantation

To determine the perioperative risk factors for bacterial infections after pediatric living donor liver transplantation (LDLT), we investigated the clinical profiles of 149 children who underwent pediatric LDLT between 1994 and 2008. Bacterial infections were diagnosed based on guidelines proposed by the Centers for Disease Control. We observed 36 bloodstream infections (BSIs) in 32/149 (21.5%) patients (0.24 infections per patient), which, 21 (58.3%) BSIs in 19 patients were due to gram-positive and 15 (41.7%) in 13 patients to gram-negative organisms. The most common pathogens of early BSI were coagulase-negative Staphylococcus; (n = 11; 30.6%) and Klebsiella pneumoniae (n = 8; 22.2%). The most common site of early BSI was catheter-related (n = 14; 38.9%). Multivariate analysis showed that age ≤ 1 year (P < .05; odds ratio [OR] = 3.90; 95% CI, 1.83-15.26) and bile duct complications (P < .05; OR = 6.2, 95% CI = 3.21-35.23) were significant independent risk factors for early BSIs. More cautious management of pediatric LDLTs may be necessary for younger age children particularly with postoperative biliary complications.

Effects of Polycan, a β-glucan, on experimental periodontitis and alveolar bone loss in Sprague-Dawley rats

BACKGROUND AND OBJECTIVE

Polycan is a promising candidate for the treatment of periodontal disease. This study was undertaken to examine whether Polycan, a type of β-glucan, has a protective effect on ligature-induced experimental periodontitis and related alveolar bone loss in Sprague-Dawley rats.

MATERIAL AND METHODS

 Polycan was orally administered, daily, for 10 d, at 21.25, 42.5 or 85 mg/kg, beginning 1 d after ligation. Changes in body weight and alveolar bone loss were monitored, and the anti-inflammatory effects of Polycan were determined by measuring the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival tissue. We also evaluated inducible nitric oxide synthase (iNOS) activity and malondialdehyde (MDA) concentrations as a measure of the antioxidant effect.

RESULTS

Ligature placement led to a marked decrease in body weight, increased alveolar bone loss and increased concentrations of MPO, IL-1β, TNF-α and MDA, as well as increased iNOS activity and inflammatory cell infiltration and decreased collagen-fiber content. Histological examination revealed increases in the number and activity of osteoclast cells, decreases in alveolar bone volume and elevated percentages of osteclasts on the alveolar bone surface. Daily oral treatment with 42.5 or 85 mg/kg of Polycan for 10 d led to significant, dose-dependent inhibition of the effect of ligature placement.

CONCLUSION

Taken together, these results suggest that 10 d of oral treatment with Polycan effectively inhibits ligature placement-induced periodontitis and related alveolar bone loss via an antioxidant effect.

Short-term clinical outcomes for 100 consecutive cases of laparoscopic pylorus-preserving pancreatoduodenectomy: improvement with surgical experience

BACKGROUND

Few reports describe the use of laparoscopic pylorus-preserving pancreaticoduodenectomy (LPPPD) in centers with experience using this technique. In addition, the clinical outcomes of this procedure remain undetermined.

METHODS

In the current study, 100 patients with benign or malignant lesions in the pancreatic head underwent LPPPD between May 2007 and December 2011. The overall clinical outcomes and changes in these outcomes during the surgeon learning period were analyzed to assess the feasibility and safety of this procedure.

RESULTS

Pathologic examination of the pancreas confirmed intraductal papillary mucinous neoplasms in 37 patients, solid pseudopapillary tumors in 17 patients, neuroendocrine tumors in 15 patients, serous cystic neoplasms in seven patients, pancreatic ductal adenocarcinomas in seven patients, ampulla of Vater tumors and duodenal gastrointestinal stromal tumors in five patients, and other disease in seven patients. The median operative time was 7.9 h, which decreased with accumulating experience of the surgeon using this procedure, from 9.8 h for the first 33 cases to 6.6 h for the last 34 cases. Complications developed in 25% of the patients, including six cases (6%) with significant pancreatic fistula [International Study Group on Pancreatic Fistula (ISGPF) grade B]. The complication rate decreased from 33.3% for the first 33 cases to 17.6% for the last 34 cases. The mean hospital stay was 14 days, which also decreased from 20.4 days for the first 33 cases to 11.5 days for the last 34 cases. For the 12 patients in the study cohort with invasive malignant disease, the median tumor size was 2.8 cm, and the median number of lymph nodes harvested was 13. All the patients had margin-negative R0 resections.

CONCLUSION

The LPPPD procedure is technically safe and feasible, with an acceptable rate of morbidity and other clinical outcomes for benign and malignant diseases. Clinical outcomes can be improved once a learning curve has been overcome.

Diagnostic sensitivity of culture and drug resistance patterns in Korean patients with intestinal tuberculosis

SETTING

It is challenging to differentiate between intestinal tuberculosis (ITB) and Crohn's disease in areas where TB is still prevalent. The use of diagnostic tools and verifying the drug resistance patterns of ITB can be helpful for its correct diagnosis.

OBJECTIVE

To determine the diagnostic sensitivity of a culture assay using colonoscopic biopsy specimens and the drug resistance patterns of Mycobacterium tuberculosis isolated from ITB.

DESIGN

Data from 400 patients diagnosed with ITB were retrospectively analysed.

RESULTS

Of the 400 patients, 170 (42.5%) were males; the median age at diagnosis was 40 years. The sensitivity of culture was 44.1% (145/329). Resistance to at least one anti-tuberculosis drug was identified in 13 (17.6%) and multidrug-resistant TB (MDR-TB) was diagnosed in two (2.7%) of the 74 patients for whom drug susceptibility testing was performed. Including M. tuberculosis isolated from respiratory specimens, the proportion of MDR-TB was 4.4% (5/113); previous anti-tuberculosis treatment was an independent risk factor for MDR-TB (26.7% vs. 1.0%, P < 0.01).

CONCLUSION

Culture of colonoscopic biopsy specimens shows substantial diagnostic sensitivity; the frequency of MDR-TB is higher in previously treated cases than in new cases.

Human insulin secreted from insulinogenic xenograft restores normoglycemia in type 1 diabetic mice without immunosuppression

In the present study, we examined the therapeutic potential of human amnion-derived insulin-secreting cells for type 1 diabetes. Human amniotic mesenchymal stem cells (hAMs) were isolated from amnion and cultivated to differentiate into insulin-secreting cells in vitro. After culture in vitro, the differentiated cells (hAM-ISCs) were intensively stained with dithizone and secreted insulin and c-peptide in a high-glucose-dependent manner. They expressed mRNAs of pancreatic cell-related genes, including INS, PDX1, Nkx6-1, NEUROG3, ISL1, NEUROD1, GLUT1, GLUT2, PC1/3, PC2, GCK, PPY, SST, and GC, and were positive for human insulin and c-peptide. Transplantation of hAM-ISCs into the kidneys of mice with streptozotocin-induced diabetes restored body weight and normalized the blood glucose levels, which lasted for 210 days. Only human insulin and c-peptide were detected in the blood of normalized mice after 2 months of transplantation, but little mouse insulin and c-peptide. Removal of graft-bearing kidneys from these mice resulted in causing hyperglycemia again. Human cell-specific gene, hAlu, and human pancreatic cell-specific genes, insulin, PDX1, GLUT1, GLP1R, Nkx6-1, NEUROD1, and NEUROG3, were detected in the graft-bearing kidneys. Colocalization of human insulin and human nuclei antigen was also observed. These results demonstrate that hAMs could differentiate into functional insulin-secreting cells in vitro, and human insulin secreted from hAM-ISCs following transplantation into type 1 diabetic mice could normalize hyperglycemia, overcoming immune rejection for a long period.

De novo autoimmune hepatitis in Korean children after liver transplantation: a single institution's experience

INTRODUCTION

De novo autoimmune hepatitis (AIH) after orthotopic liver transplantation (OLT) has been described as a new type of late graft dysfunction in children who have not undergone transplantation for previous autoimmune liver disease. The purpose of this study was to evaluate the clinical aspects of de novo AIH among children following OLT.

PATIENTS AND METHODS

Between January 1994 and May 2007, 149 children underwent OLT, including 1 with recurrent AIH who was excluded from this study, whereas 4 others developed de novo AIH (2.7%; n = 4/148). We analyzed the demographics, laboratory characteristics, and response to treatment of the 4 children with de novo AIH following OLT.

RESULTS

The 4 patients were all girls with a median interval after OLT to presentation of 6.5 years (range, 0.7-8.8 years). The median age when de novo AIH developed was 12.4 years (range, 8.7-17.3 years). All cases were detected by abnormal liver function tests, namely, increased aspartate aminotransferase (AST; median, 322 IU/L; range, 181-919 IU/L). One patient showed elevated immunoglobulin G. Three patients displayed positive antinuclear antibodies. All were seronegative for smooth muscle antibody and liver-kidney microsomal type 1 antibody. One patient showed anti-mitochondrial antibody. All patients were treated with steroids with or without azathioprine. The liver function tests in these 4 patients, improved by at least 50% during the first month of treatment, responding to steroid treatment with or without azathioprine.

CONCLUSION

In preadolescent or adolescent female patients with unexplained graft dysfunction after OLT, it is important to recognize de novo AIH rapidly and to develop an adequate diagnostic strategy, including evaluation of serum autoantibodies, immunoglobulin G, and liver biopsy.

Adenosine A2A receptor polymorphisms in Korean patients with systemic sclerosis

Adenosine A2A receptor (ADORA2A) regulates inflammation, promotes tissue repair and collagen production by human dermal fibroblasts. We investigated the genetic polymorphisms of ADORA2A in susceptibility to systemic sclerosis (SSc). We genotyped 142 Korean SSc patients and 150 controls for polymorphisms of -1751A/C (rs5996696) and 1976C/T (rs5751876), to cover the promoter and all exon sequences of ADORA2A in Koreans, using TaqMan fluorogenic 5' nuclease assay and single base primer extension assay. Neither -1751A/C nor 1976C/T polymorphism showed difference in the distribution of alleles or genotypes between patients and controls with allele frequency of 89.9% v 91.0% for -1751A (p=0.64) and 56.5% v 54.0% for 1976C (p=0.55). Our findings suggest that the role of ADORA2A in SSc may not be genetically related.

Comparison of open and laparoscopic live donor left lateral sectionectomy

BACKGROUND

The present study was undertaken to determine whether laparoscopic live donor left lateral sectionectomy (LLS) in paediatric liver transplantation is a feasible, safe and reproducible procedure, compared with open live donor left lateral sectionectomy (OLS).

METHODS

A retrospective review was conducted of all consecutive live donor procedures for paediatric liver transplantation performed between May 2008 and October 2009. All live donor hepatectomies were carried out by a single surgeon.

RESULTS

A total of 26 live donor procedures for paediatric liver transplantation were performed, of which 11 were LLS and 11 OLS; four left hepatectomies were excluded. The LLS group had a significantly shorter hospital stay (mean(s.d.) 6·9(0·3) versus 9·8(0·9) days; P = 0·001) and time to oral diet (2·1(0·3) versus 2·7(0·4) days; P = 0·012). Duration of operation, blood loss, warm ischaemia time and out-of-pocket medical costs were comparable between groups. There was no death in either donor group and only one complication, a wound seroma, in the OLS group.

CONCLUSION

LLS seemed to be a safe, feasible and reproducible procedure, and was associated with reduced hospital stay.

Expression of RUNX3 in skin cancers

BACKGROUND

Expression of Runt-related transcription factor 3 (RUNX3) is reduced in a large number of cancers. However, a few studies have reported higher expression of RUNX3 in several cancers, including basal cell carcinoma (BCC). In light of this, we explored the expression of RUNX3 in skin cancers generally, to determine whether it acts as an oncogene or a tumour-suppressor gene in skin tumours.

AIM

To investigate the expression of RUNX3 in normal skin and malignant skin tumours.

METHODS

RUNX3 expression was evaluated by western blotting in 24 specimens, comprising 6 malignant melanoma (MM), 6 squamous cell carcinoma (SCC), 6 BCC and 6 normal skin specimens. Immunohistochemical staining was carried out to analyse RUNX3 expression in 16 MM, 16 SCC and 16 BCC specimens. To identify where the protein was expressed, the cytoplasmic and nuclear protein expression of RUNX3 in skin cancer tissues was determined. A cell-proliferation study was performed on an MM line (G361) by small interfering (si)RNA transfection.

RESULTS

The western blotting experiments showed that RUNX3 was not expressed in normal skin tissues, but it was overexpressed in all MM and SCC samples, and in five of the six BCC samples. Using immunochemistry, RUNX3 was found to be overexpressed in all cancer tissues analysed. Subcellular fraction analysis revealed that RUNX3 was expressed in the nuclei but not the cytoplasm of all the skin cancer tissues analysed, and RUNX3 silencing by siRNA in G361 cells resulted in a decrease in proliferation.

CONCLUSIONS

Based on these results, we suggest that RUNX3 has an oncogenic potential and does not act as a tumour suppressor in skin cancers.

Effect of necrosis modulator necrox-7 on hepatic ischemia-reperfusion injury in beagle dogs

OBJECTIVE

The liver is susceptible to ischemia-reperfusion (IR) injury during inflow occlusion for hepatectomy. There is no effective pharmacologic agent available to prevent the release of high-mobility-group box 1 (HMGB1) or to ameliorate IR injury. This pilot study sought to develop a model in beagle dogs for the purpose of testing the efficacy of a necrosis modulator, necrox-7, to prevent hepatic IR injury in beagle dogs.

METHODS

Six male beagle dogs were randomly assigned to the control group (group A; n = 3) or the treatment group (group B; n = 3). Under general anesthesia, group B received intravenous infusion of necrox-7 (13 mg/kg over 20 minutes) followed by 60 minutes of left hepatic inflow occlusion and 60 minutes of reperfusion. Both groups were tested for serum biochemicals, hematology values, liver biopsies, and plasma HMGB1 levels over a 48-hour period.

RESULTS

The maximum alanine transferase (ALT), aspartate transferase (AST), and lactate dehydrogenase (LDH) levels among group A versus group B were: ALT 868.3 ± 337.4 IU/L vs 274.3 ± 72.6 IU/L (P = .041); AST 1,024.7 ± 246.5 IU/L vs 505.3 ± 66.7 IU/L (P = .024); and LDH 962.7 ± 226.2 IU/L vs 552.7 ± 62.4 IU/L (P = .039). Liver biopsy demonstrated marked necrosis and inflammatory infiltrates in group A, whereas group B showed little evidence of IR injury. The plasma HMGB1 concentration was significantly lower among group B versus A.

CONCLUSION

This pilot study developed a hepatic IR injury model, demonstrating that necrox-7 reduced hepatic necrosis secondary to IR injury in a large animal setting.

Survival rate of H5N1 highly pathogenic avian influenza viruses at different temperatures

The survival rate of Korean H5N1 highly pathogenic avian influenza (HPAI) viruses was investigated at different temperatures under the laboratory conditions. The estimated survival days for a starting viral concentration of 10(6.5) 50% egg infectious dose/0.1 mL were 930, 1,042, and 3,213 d at 4 degrees C; 226, 232, and 293 d at 20 degrees C; and 51, 55, and 58 d at 30 degrees C for A/chicken/Korea/ES/03, A/chicken/Korea/IS/06, and A/chicken/Korea/Gimje/08 (Gimje/08) viruses, respectively. The stability of the Gimje/08 virus was statistically significant compared with the other 2 viruses except for the data between Gimje/08 and A/chicken/Korea/IS/06 virus at 30 degrees C. This result indicated that the survival rate of 3 Korean HPAI viruses is different at various temperatures, which might have partially influenced the large scale of HPAI outbreak in Korea in 2008.

Salmonella gallinarum gyrA mutations associated with fluoroquinolone resistance

Salmonella enterica subsp. enterica serovar Gallinarum (S. gallinarum) is the causative organism of fowl typhoid, and an outbreak of fowl typhoid in Korea was confirmed in 1992. The aim of this study was to investigate possible changes in fluoroquinolone susceptibility among S. gallinarum isolates from 1995 to 2001, and to analyse mutations of the gyrA gene in fluoroquinolone-resistant isolates. Among 258 S. gallinarum isolates tested by the disk diffusion method, isolates from 1995 (n=18) were susceptible to all fluoroquinolones tested, whereas a number of isolates from 2001 (n=46) showed reduced susceptibility to enrofloxacin (6.5%), ciprofloxacin (10.9%), norfloxacin (52.5%) and ofloxacin (82.6%). The minimum inhibitory concentration range of enrofloxacin, ciprofloxacin, norfloxacin, ofloxacin and danofloxacin increased from < or =0.06 approximately 0.25 microg/ml in 1995 to 2 approximately 8 microg/ml in 2001. When amino acid changes in the gyrA were analysed by DNA sequencing, 22.5% and 14.7% among 258 isolates had a mutation at the Ser-83 and Asp-87 codons, respectively, and the prevalence of these mutants increased from 5.6% in 1995 to 89.1% in 2001. These mutants contained a change from Ser to Phe or Tyr at codon 83, or a change from Asp to Gly, Tyr or Asn at codon 87, and showed a range of minimum inhibitory concentrations of enrofloxacin from 0.5 to 8 microg/ml, ciprofloxacin from 0.25 to 4 microg/ml, norfloxacin from 2 to 32 microg/ml, ofloxacin from 0.5 to 4 microg/ml, and danofloxacin from 0.5 to 4 microg/ml. These results suggested an important association between the gyrA mutations and fluoroquinolone resistance of S. gallinarum.

Characterization of antimicrobial resistance of recent Salmonella enterica serovar Gallinarum isolates from chickens in South Korea

Salmonella enterica serovar Gallinarum isolates (n=105) from chickens in South Korea between 2002 and 2007 were tested for antimicrobial susceptibility by determining minimum inhibitory concentrations of 16 antimicrobials, and their predominant resistance profiles were genetically characterized. Most isolates (99/105; 94.3%) were resistant to nalidixic acid and resistant/intermediately resistant to fluoroquinolones, and 63.8% (67/105) of the isolates were resistant to three or more antimicrobials. Forty-two quinolone-resistant isolates, of which the quinolone resistance-determining regions of the gyrA genes were sequenced, contained a substitution of a Ser to a Phe or Tyr at position 83 (71.4%), or a substitution of an Asp to an Asn, Gly, or Tyr at position 87 (28.6%). Fifty-seven sulphamethoxazole-resistant isolates were tested for the presence of class 1 integrons by polymerase chain reaction, and their resistance gene cassettes were analysed by sequencing. Three different class 1 integrons containing the resistance-gene insert aadA (52.6%; n=30), aadB (12.3%; n=7), or aadB-aadA (12.3%; n=7) were identified. Most isolates harbouring the integron containing aadB-aadA displayed resistance to all three aminoglycosides tested and also showed increased resistance to fluoroquinolones. These findings suggest that fluoroquinolone resistance may be epidemiologically linked to multiple aminoglycoside resistance.

The susceptibility of magpies to a highly pathogenic avian influenza virus subtype H5N1

Korean wild magpies (Pica pica sericea) were intranasally inoculated with highly pathogenic avian influenza (A/Chicken/Korea/ES/03 virus) (H5N1), which was classified as clade 2.5. We estimated viral replication, death after infection, and histology and immunohistochemistry. This species was highly susceptible to severe infection; 100% of birds died within 5 to 8 d. The virus was detected from oropharyngeal (1 to 5 d postinfection) and cloacal (3 to 5 d postinfection) swabs from infected magpies. At necropsy, the prominent lesions were coalescing necrosis of the pancreas with enlargement of livers and spleens. Microscopically, pancreas, brain, heart, adrenal gland, and kidney were most consistently affected with necrotic and inflammatory changes, and viral antigen was frequently demonstrated in the parenchyma of these organs. As a result, Korean wild magpies were very susceptible to avian influenza (H5N1) virus.

The effect of 3D hydrogel scaffold modulus on osteoblast differentiation and mineralization revealed by combinatorial screening

Cells are known to sense and respond to the physical properties of their environment and those of tissue scaffolds. Optimizing these cell-material interactions is critical in tissue engineering. In this work, a simple and inexpensive combinatorial platform was developed to rapidly screen three-dimensional (3D) tissue scaffolds and was applied to screen the effect of scaffold properties for tissue engineering of bone. Differentiation of osteoblasts was examined in poly(ethylene glycol) hydrogel gradients spanning a 30-fold range in compressive modulus ( approximately 10 kPa to approximately 300 kPa). Results demonstrate that material properties (gel stiffness) of scaffolds can be leveraged to induce cell differentiation in 3D culture as an alternative to biochemical cues such as soluble supplements, immobilized biomolecules and vectors, which are often expensive, labile and potentially carcinogenic. Gel moduli of approximately 225 kPa and higher enhanced osteogenesis. Furthermore, it is proposed that material-induced cell differentiation can be modulated to engineer seamless tissue interfaces between mineralized bone tissue and softer tissues such as ligaments and tendons. This work presents a combinatorial method to screen biological response to 3D hydrogel scaffolds that more closely mimics the 3D environment experienced by cells in vivo.

A case of systemic polyarteritis nodosa involving bronchial artery

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis involving predominantly medium-sized muscular arteries. It commonly involves skin, kidney, cardiovascular system, gastrointestinal system, and neurological system. But bronchial artery involvement of PAN is rarely identified. We report a case of PAN with initial presentation of hemoptysis. On admission, chest radiograph and chest CT angiography revealed no focus of bleeding. Angiography showed a bronchial artery aneurysm and multiple arterial aneurysms in both renal, hepatic, mesenteric and branches of small bowel arteries. These findings were compatible with the diagnosis of PAN. The patient was started on steroid and cyclophosphamide.

TRAIL gene-armed oncolytic poxvirus and oxaliplatin can work synergistically against colorectal cancer

We have explored a unique combination therapy for metastatic colorectal cancer. This strategy combines a potent and new oncolytic poxvirus expressing a membrane-bound tumor necrosis factor-related apoptosis-inducing ligand (TRAIL or TNFSF10) and oxaliplatin (Ox) chemotherapy. We hypothesized that TRAIL expression would increase the efficacy of the oncolytic poxvirus, and that the therapeutic efficacy would be further enhanced by combination with chemotherapy. The cytotoxicity to cancer cells by Ox, oncolytic vaccinia virus (VV) and trail gene-armed VV alone or in combination was tested in vitro. The trail gene armed oncolytic VV-expressed high levels of TRAIL in infected cancer cells and had greater potency as a cytotoxic agent compared with the parent VV. Ox alone exerted concentration-dependent cytotoxicity. In vitro, the combination of the two agents applied at suboptimal concentrations for individual therapy displayed synergy in inducing cancer cells into enhanced levels of apoptosis/necrosis. Western blot analyses were consistent with the notion that TRAIL induced cancer cell death mainly through apoptosis, whereas Ox and vJS6 induced cell death more through non-apoptotic death pathways. In two aggressive colorectal carcinomatosis models derived from human HCT116 and murine MC38 cells, the combination therapy displayed synergistic or additive antitumor activity and prolonged the survival of the tumor-bearing mice compared with either Ox chemotherapy or vvTRAIL-mediated oncolytic gene therapy alone. This combination strategy may provide a new avenue to treating peritoneal carcinomatosis and other types of metastases of colorectal cancer.

Tnk1/Kos1: a novel tumor suppressor

Tnk1/Kos1 is a non-receptor protein tyrosine kinase implicated in negative regulation of cell growth by a mechanism involving inhibition of Ras activation and requiring Tnk1/Kos1's intrinsic catalytic activity. Tnk1/Kos1 null mice were created by homologous recombination by deleting the catalytic domain. Upon aging, both Tnk1+/- and Tnk1-/- mice develop spontaneous tumors, including lymphomas and carcinomas at high rates (i.e. 27%, and 43%, respectively), indicating that Tnk1/Kos1 is a tumor suppressor. Tissues from Tnk1/Kos1-null mice exhibit proportionally higher levels of basal and growth factor-stimulated Ras activation. Mechanistically, Tnk1/Kos1 requires either or both Y277 and Y287 sites to be intact for enzymatic activity and phosphorylation of its substrate, growth factor receptor binding protein 2 (Grb2). Data indicate that following tyrosine phosphorylation of Grb2 by Tnk1/Kos1, the Grb2-Sos1 guanine exchange factor (GEF) complex that mediates growth factor stimulated Ras activation becomes disrupted, resulting in the reversal of Ras activation. Conversely, the loss of Tnk1/Kos1 activity results in constitutive activation of Ras due to prolonged stabilization/activation of the Grb2-Sos1 GEF activity. Tnk1/Kos1 is the first tyrosine kinase discovered to have tumor suppressor activity, and the mechanism of spontaneous tumor formation involves constitutive, indirect activation of Ras. Thus, Ras may display "oncogenic activity" without undergoing "oncogenic" mutation. We now find that a cohort of patients with diffuse large B-cell lymphoma (DLBCL) display downregulation of Tnk1/Kos1 that may account for tumorigenesis in humans.

Ultrastructural changes in corpora allata during a cycle of juvenile hormone biosynthesis in embryos of the viviparous cockroach, Diploptera punctata

We have observed changes with time in the fine structure of corpora allata (CA) during a known cycle of increasing and decreasing juvenile hormone (JH) synthesis in late embryos of Diploptera punctata. A previous report showed that rates of JH release were relatively low in 28-day-old embryos, but CA activity subsequently rose linearly to a peak on about day 42, and thereafter steadily declined to a low level on day 64 just before birth (Holbrook et al., 1997). We now show that, regardless of rate of JH synthesis, CA cells are large and replete with organelles which nevertheless exhibit variable morphology in embryos of different age. Highly active CA cells on day 40 contain abundant ring-form mitochondria, whereas CA cells of low activity on days 28 and 64 contain mitochondria that are rod-shaped or globular. Mitochondrial cristae were scarce and indistinct on day 28 but numerous and well developed on day 64. Endoplasmic reticula (ER) are rare on day 28 and appear in increasing numbers when CA activity rises. On day 40, ER are abundant and often exhibit a whorl-like appearance which is not observed on day 28. After day 44, when biosynthetic activity is declining, whorls of ER gradually decrease in number and are ultimately replaced by vesicular smooth ER on day 64. Neurosecretions are found only after day 38, by which time rates of JH synthesis have increased substantially from those of day 28. Except for membranous autophagic vacuoles, which are frequently found when ER whorls disintegrate as rates of JH synthesis decline toward birth, most autophagic vesicles such as multivesicular vesicles and dense bodies occur only sporadically among CA cells at all examined ages. We conclude that synchronous autophagy of exhausted organelles, which results in atrophy of CA cells and long-term arrest of JH synthesis in adult females of D. punctata, does not occur in embryos. The slow cyclic change in rate of JH synthesis in embryonic CA is most likely due to asynchronous autophagic activity and to alterations in certain unique features of intracellular organelles.