p53, BCL-2, and Ki-67 expression according to tumor response after concurrent chemoradiotherapy for advanced rectal cancer

BACKGROUND

Concurrent chemoradiotherapy (CCRT) for locally advanced rectal cancer is an important modality for curative resection, but tumors show wide spectrum response. The purpose of this study was to investigate any correlation among related genetic mutations, proliferative index, and tumor response after CCRT.

METHODS

This study included 23 patients with rectal cancer, who were preoperatively staged as at least T3 N1 or T4 (determined by transrectal ultrasonography and MRI). Enrolled patients were given 5-FU 450 mg/m2/day and leucovorin 20 mg/m2/day intravenously for 5 days during weeks 1 and 5 of radiotherapy (45-54 Gy). Surgical resection was performed 4 weeks after completion of the scheduled treatment. Tumor response was classified as CR (complete response), PR (partial response: 50% diminution of tumor volume and downstaging), and NR (no response). Paraffin-embedded tissue obtained before chemoradiotherapy was studied by immunohistochemical staining for p53, BCL-2, and Ki-67. The extent of tumor response was correlated with proliferative activity and was measured by immunostaining Ki-67 proliferative antigen and the expression of p53 and BCL-2 oncoproteins.

RESULTS

All patients were resectable. CR was obtained in 4 patients, PR in 10 patients, and NR in 9 patients. The p53 mutation was noted in 16 patients: NR in 5 patients, PR in 9 patients, and CR in 2 patients (P = .638). BCL-2 expression was noted in 11 patients: NR in 4 patients, PR in 3 patients, and CR in 4 patients (P = .799). The Ki-67 labeling index was NR: 615.4+/-47.2; PR: 663.2+/-20.4; and CR: 765.5+/-58.3 (CR + PR vs. NR, P = .029).

CONCLUSIONS

Immunohistochemical expression of p53 and BCL-2 does not correlate with tumor response after CCRT, but Ki-67 labeling may be a useful parameter for radiosensitive tumors selected for CCRT.

Modulating angiotensin II-induced inflammation by HMG Co-A reductase inhibition

Angiotensin (Ang) II is capable of producing inflammatory changes by signals through its AT1 receptor. Reactive oxygen species production, adhesion molecule expression, chemokines, and other mediators are involved. Nuclear factor-kappaB (NK-kappaB) and activator protein 1 (AP-1) are two of the transcription factors activating the responsible genes. We have studied Ang II-independent modulating effects in a double transgenic rat model harboring the human renin and angiotensinogen genes. We have recently focused on the protective effects of HMG-CoA reductase inhibition and review these data here. We found that cerivastatin decreased mortality, lowered blood pressure, preserved renal function, decreased cardiac hypertrophy, and inhibited the entire chain of inflammatory events. Furthermore, NF-kappaB and AP-1 activation was sharply attenuated. We also observed that cerivastatin blocked ERK1/2 phosphorylation in vivo and in vitro. Cerivastatin also inhibited phorbol ester-transmitted events in vascular smooth muscle cells. Because Rho, a member of the Ras protein superfamily is important to Ang II-dependent and -independent vascular smooth muscle signaling events, we suggest that cerivastatin may act by inhibiting the prenylation, membrane anchoring, and subsequent activation of Ras proteins. These data may in part explain cholesterol-independent, HMG-CoA reductase-related, protective effects.

Non-combustible waste vitrification with plasma torch melter

Non-combustible radioactive wastes generated from Nuclear Power Plants (NPPs) are composed of concrete, glass, asbestos, metal, sand, soil, spent filters, etc. The melting tests for concrete, glass, sand, and spent filters were carried out using a 60 kW plasma torch system. The surrogate wastes were prepared for the tests. Non-radioactive Co and Cs were added to the surrogates in order to simulate the radioactive waste. Several kinds of surrogate prepared by their own mixture or by single waste were melted with the plasma torch system to produce glassy waste forms. The characteristics of glassy waste forms were examined for the volume reduction factor (VRF) and the leach rate. The VRFs were estimated through the density measurement of the surrogates and the glassy waste forms, and were turned out to be 1.2-2.4. The EPA (Environmental Protection Agency) Toxicity Characteristic Leaching Procedure (TCLP) was used to determine the leach resistance for As, Ba, Hg, Pb, Cd, Cr, Se, Co, and Cs. The leaching index was calculated using the total content of each element in both the waste forms and the leachant. The TCLP tests resulted in that the leach rates for all elements except Co and Cs were lower than those of the Universal Treatment Standard (UTS) limits. There were no UTS limits for Co and Cs, and their leach rate & index from the experiments were resulted in around 10 times higher than those of other elements.

A biological phosphorus removal potential test for wastewaters

A simple test was proposed to assess whether phosphorus in a wastewater can be removed using a biological phosphorus removal (BPR) process. The test includes the measurement of phosphorus release during 2 hours of the anaerobic stage in a batch reactor containing phosphorus-accumulating organisms (PAOs) and estimation of the effluent phosphorus concentration using biochemical relationships. The BPR potential test developed allowed for the successful evaluation of BPR feasibility for five wastewater samples. The BPR potential test was validated by comparing the test results with the effluent phosphorus concentrations measured in a sequencing batch reactor (SBR). An effluent phosphorus concentration of 1.9 mg P/L predicted for the BPR potential test performed was close to the effluent phosphorus concentration of 1.8 mg P/L obtained from an SBR on the same day. During the anaerobic stage, phosphorus release was significantly affected by the sludge concentration initially, but became insignificant after 2 hours. The initial sludge concentration affected the phosphorus release rate; thus, it is recommended that the BPR potential test be conducted at a target mixed liquor volatile suspended solids concentration. It is also recommended that the BPR potential test be conducted at the site where the PAO-containing sludge is available and the wastewater sample can be delivered at 4 degrees C in less than 24 hours. The PAOs in different sludges had almost identical phosphorus release after 2 hours; however, the characteristics of facultative bacteria in sludges affected the phosphorus release. If the wastewater is prefermented for at least 3 days before the BPR potential test, the amount of phosphorus released by various PAO-containing sludges is expected to be identical.

Gain- and loss-of-function of Rhp51, a Rad51 homolog in fission yeast, reveals dissimilarities in chromosome integrity

Rad51 is crucial not only in homologous recombination and recombinational repair but also in normal cellular growth. To address the role of Rad51 in normal cell growth we investigated morphological changes of cells after overexpression of wild-type and a dominant negative form of Rad51 in fission yeast. Rhp51, a Rad51 homolog in Schizosaccharomyces pombe, has a highly conserved ATP-binding motif. Rhp51 K155A, which has a single substitution in this motif, failed to rescue hypersensitivity of a rhp51 mutant to methyl methanesulfonate (MMS) and UV, whereas it binds normally to Rhp51 and Rad22, a Rad52 homolog. Two distinct cellular phenotypes were observed when Rhp51 or Rhp51 K155A was overexpressed in normal cells. Overexpression of Rhp51 caused lethality in the absence of DNA-damaging agents, with acquisition of a cell cycle mutant phenotype and accumulation of a 1C DNA population. On the other hand, overexpression of Rhp51 K155A led to a delay in G(2) with decondensed nuclei, which resembled the phenotype of rhp51. The latter also exhibited MMS and UV sensitivity, indicating that Rhp51 K155A has a dominant negative effect. These results suggest an association between DNA replication and Rad51 function.

Dicobalt octacarbonyl catalyzed carbonylated cycloaddition of triynes to functionalized tetracycles

[reaction: see text]. We have demonstrated that a dicobalt octacarbonyl catalyzed double [2 + 2 + 1] carbonylative cycloaddition reaction of triyne can be carried out to yield a novel 5.5.5.6 tetracyclic di-enone system.

Nitric oxide synthase isoforms I, III and protein kinase-Ctheta in skeletal muscle fibres of normal and streptozotocin-induced diabetic rats with and without Ginkgo biloba extract treatment

The expression of nitric oxide synthase (NOS) isoforms I, III and protein kinase-Ctheta (PKCtheta) in rat vastus lateralis muscle was demonstrated immunohistochemically and then correlated to the physiological metabolic fibre types: SO (slow-oxidative), FOGI, FOGII (fast-oxidative glycolytic; I more glycolytic, II more oxidative), and FG (fast-glycolytic). NOS expression in muscles from different experimental groups (normal and diabetic rats, with and without Ginkgo biloba extract treatment) was assayed by Western blotting. Generally, NOS I and PKCtheta were co-expressed in fibres with predominantly oxidative metabolism (SO, FOGII). This suggests an interplay of PKCtheta and NOS I in nitric oxide production by oxidative fibres. NOS III was more highly expressed in fibres with predominantly glycolytic metabolism (FOGI, FG). A somewhat lower NOS I immunoreactivity was also found in NOS III positive fibres suggesting that NOS III and NOS I are co-expressed in these fibres. Western blotting revealed that NOS I as well as NOS III expression in the vastus lateralis muscle was down-regulated in diabetes and increased after Ginkgo biloba extract treatment. These effects may be associated with a diminished glucose uptake by myocytes of diabetic musclesand with an improved muscle function after Ginkgo biloba treatment.

Increased expression of peroxiredoxin II confers resistance to cisplatin

Peroxiredoxin II (Prx II) has been known to be induced by various oxidative stimuli and to play an important protective role from oxidative damage by hydrogen peroxide (H2O2). In this study, we observed that cisplatin as well as H2O2 induced Prx II expression. To examine the correlation between the increased expression of Prx II and chemoresistance, we prepared a Prx II-overexpressing cell line, SNU638 cells, and found it to be more resistant to cell death induced by cisplatin and H2O2 than neo-transfectant cells. We also observed that enhanced expression of Prx II inhibited cisplatin- and H2O2-induced apoptosis, demonstrating that resistance to these cytotoxic agents was due to inhibition of apoptosis. The above results led us to suggest that the overexpressed Prx II protein inhibits cisplatin-induced apoptosis, thereby contributing to chemoresistance of tumor cells, especially to oxidative stress producing anticancer drugs.

Glucocerebrosidase mutations among African-American patients with type 1 Gaucher disease

While the inherited deficiency of the enzyme glucocerebrosidase (Gaucher disease) is panethnic in its distribution, there have not been studies of the mutations encountered in specific ethnic groups in the United States, other than those on Ashkenazi Jews. We present the clinical descriptions and genotypes of seven patients of African-American ancestry with type 1 Gaucher disease, and summarize the published literature regarding the genotypes encountered in this population. All seven of the patients had moderate-to-severe manifestations of the disease, and all developed symptoms by adolescence. Genotypic analyses revealed that no two probands shared the same genotype. The common mutations N370S, c.84-85insG, IVS2+1 G-->A, and R463C were not seen. Mutation L444P was present on one allele in each of the patients; but the same mutation was encountered as a single point mutation in three of the patients, and as part of a recombinant allele in four of the patients. Southern blot analyses revealed a glucocerebrosidase fusion allele in one patient, and a duplication resulting from recombination in the region downstream from the glucocerebrosidase gene in three of the patients. Five different point mutations (A90T, R48W, N117D, R170C, and V352L), one deletion mutation (c.222-224 delTAC), and one insertion mutation (c.153-154 insTACAGC) were encountered. Our results demonstrate that there is significant genotypic heterogeneity among African-American patients with type 1 Gaucher disease, and that recombinations in the glucocerebrosidase gene locus are particularly common in this patient group. Published 2001 Wiley-Liss, Inc.

Plakophilin 1 interferes with plakoglobin binding to desmoplakin, yet together with plakoglobin promotes clustering of desmosomal plaque complexes at cell-cell borders

Desmosomes are adhesive junctions that link intermediate filament networks to sites of strong intercellular adhesion. These junctions play an important role in providing strength to tissues that experience mechanical stress such as heart and epidermis. The basic structural elements of desmosomes are similar to those of the better-characterized adherens junctions, which anchor actin-containing microfilaments to cadherins at the plasma membrane. This linkage of actin to classic cadherins is thought to occur through an indirect mechanism requiring the associated proteins, alpha- and beta-catenin. In the case of desmosomes, both linear and lateral interactions have been proposed as playing an important role in formation of the plaque and linkage to the cytoskeleton. However, the precise nature of these interactions and how they cooperate in desmosome assembly are poorly understood. Here we employ a reconstitution system to examine the assembly of macromolecular complexes from components found in desmosomes of the differentiated layers of complex tissues. We demonstrate the existence of a Triton-soluble complex of proteins containing full length desmoplakin (DP), the arm protein plakoglobin, and the cytoplasmic domain of the desmosomal cadherin, desmoglein 1 (Dsg1). In addition, full length DP, but not an N-terminal plakoglobin binding domain of DP, co-immunoprecipitated with the Dsg1 tail in the absence of plakoglobin in HT1080 cells. The relative roles of the arm proteins plakoglobin and plakophilin 1 (PKP1) were also investigated. Our results suggest that, in the Triton soluble pool, PKP1 interferes with binding of plakoglobin to full length DP when these proteins are co-expressed. Nevertheless, both plakoglobin and PKP1 are required for the formation of clustered structures containing DP and the Dsg1 tail that ultrastructurally appear similar to desmosomal plaques found in the epidermis. These findings suggest that more than one armadillo family member is required for normal assembly and clustering of the desmosomal plaque in the upper layers of the epidermis.

Ovalbumin fused with diphtheria toxin protects mice from ovalbumin induced anaphylactic shock

For those with allergy, vaccination with a specific allergen has often been used as a major therapeutic measure. However, the universal application of this technique in clinics have been restricted due to its low success rates and the risk of active systemic anaphylactic shock (ASAS). In this regard, we constructed a fusion protein (OVA-DT), ovalbumin (OVA) fused with diphtheria toxin protein (DT), which may exert a specific cytotoxicity to cells bearing OVA-specific IgE. Its therapeutic effect was evaluated in mice (BALB/c) sensitized with OVA (Os-mice). OVA challenges to the OVA-sensitized mice (Os-mice) caused ASAS to death within 30 min, but OVA-DT treatment afforded mice complete protection. When OVA-DT was treated to the Os-mice, none showed the signs of ASAS when re-challenged 48 h after the treatment. OVA-DT itself was not found to be toxic or allergenic in normal mice. The effect of OVA-DT on the biological functions of mast cells was also studied. Binding of OVA-DT to OVA-specific IgE bearing mast cells and the inhibition of histamine release from these cells were observed. In addition, OVA-DT treatment inhibited the proliferation of OVA-specific B cells in mice. In Os-mice treated with OVA-DT, levels of anti-OVA IgG2a in serum and the production of IFN-gamma by splenic lymphocytes were found to increase, but the production of IL-4 by these cells decreased. Re-direction of cytokine profiles from OVA-specific Th2 to OVA-specific Thl is suggested. These results indicate that OVA-DT can protect Os-mice from ASAS due to OVA challenge, because it inactivates OVA-specific IgE-expressing cells, including mast cells and B cells.

Endothelial dysfunction and salt-sensitive hypertension in spontaneously diabetic Goto-Kakizaki rats

Endothelial dysfunction is associated with hypertension, hypercholesterolemia, and heart failure. We tested the hypothesis that spontaneously diabetic Goto-Kakizaki (GK) rats, a model for type 2 diabetes, exhibit endothelial dysfunction. Rats also received a high-sodium diet (6% NaCl [wt/wt]) and chronic angiotensin type 1 (AT(1)) receptor blockade (10 mg/kg PO valsartan for 8 weeks). Compared with age-matched nondiabetic Wistar control rats, GK rats had higher blood glucose levels (9.3+/-0.5 versus 6.9+/-0.2 mmol/L for control rats), 2.7-fold higher serum insulin levels, and impaired glucose tolerance (all P<0.05). Telemetry-measured mean blood pressure was 15 mm Hg higher in GK rats (P<0.01) compared with control rats, whereas heart rates were not different. Heart weight- and kidney weight-to-body weight ratios were higher in GK rats (P<0.05), and 24-hour albuminuria was increased 50%. Endothelium-mediated relaxation of noradrenaline-precontracted mesenteric arterial rings by acetylcholine was impaired compared with the control condition (P<0.05), whereas the sodium nitroprusside-induced relaxation was similar. Preincubation of the arterial rings with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester and the cyclooxygenase inhibitor diclofenac inhibited relaxations to acetylcholine almost completely in GK rats but not in Wistar rats, suggesting that endothelial dysfunction can be in part attributed to reduced relaxation via arterial K(+) channels. Perivascular monocyte/macrophage infiltration and intercellular adhesion molecule-1 overexpression were observed in GK rat kidneys. A high-sodium diet increased blood pressure by 24 mm Hg and 24-hour albuminuria by 350%, induced cardiac hypertrophy, impaired endothelium-dependent relaxation further, and aggravated inflammation (all P<0.05). The serum level of 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased 400% in GK rats on a high-sodium diet. Valsartan decreased blood pressure in rats fed a low-sodium diet and prevented the inflammatory response. In rats fed a high-sodium diet, valsartan did not decrease blood pressure or improve endothelial dysfunction but protected against albuminuria, inflammation, and oxidative stress. As measured by quantitative autoradiography, AT(1) receptor expression in the medulla was decreased in GK compared with Wistar rats, whereas cortical AT(1) receptor expression, medullary and cortical angiotensin type 2 (AT(2)) receptor expressions, and adrenal ACE and neutral endopeptidase expressions were unchanged. A high-sodium diet did not influence renal AT(1), AT(2), ACE, or neutral endopeptidase expressions. In valsartan-treated GK rats, the cortical and medullary AT(1) receptor expressions were decreased in the presence and absence of a high-sodium diet. A high-sodium diet increased plasma brain natriuretic peptide concentrations in presence and absence of valsartan treatment. We conclude that hypertension in GK rats is salt sensitive and associated with endothelial dysfunction and perivascular inflammation. AT(1) receptor blockade ameliorates inflammation during a low-sodium diet and partially protects against salt-induced vascular damage by blood pressure-independent mechanisms.

Mineralocorticoid receptor affects AP-1 and nuclear factor-kappab activation in angiotensin II-induced cardiac injury

Aldosterone is implicated in cardiac hypertrophy and fibrosis. We tested the role of the mineralocorticoid receptor in a model of angiotensin II-induced cardiac injury. We administered spironolactone (SPIRO; 20 mg. kg(-1). d(-1)), valsartan (VAL; 10 mg. kg(-1). d(-1)), or vehicle to rats double transgenic for the human renin and angiotensinogen genes (dTGR). We investigated basic fibroblast growth factor (bFGF), platelet-derived growth factor, transforming growth factor-beta(1), and the transcription factors AP-1 and nuclear factor (NF)-kappaB. We used immunohistochemistry, electrophoretic mobility shift assays, and TaqMan RT-PCR. Untreated dTGR developed hypertension, cardiac hypertrophy, vasculopathy, and fibrosis with a 50% mortality rates at 7 weeks. SPIRO and VAL prevented death and reversed cardiac hypertrophy, while only VAL normalized blood pressure. Both drugs prevented vasculopathy. bFGF was markedly upregulated in dTGR, whereas platelet-derived growth factor-B and transforming growth factor-beta(1) were little changed. VAL and SPIRO suppressed this upregulation. Both AP-1 and NF-kappaB were activated in dTGR compared with controls. VAL and SPIRO reduced both transcription factors and reduced bFGF, collagen I, fibronectin, and laminin in the interstitium. These findings show that aldosterone promotes hypertrophy, cardiac remodeling, and fibrosis, independent of blood pressure. The effects involve AP-1, NF-kappaB, and bFGF. Mineralocorticoid receptor blockade downregulates these effectors and reduces angiotensin II-induced cardiac damage.

Meta-analysis of hypertension as a risk factor of cerebrovascular disorders in Koreans

This study was conducted to integrate the results of previous studies which evaluated hypertension as a risk factor for cerebrovascular disorders (CVD) in Koreans. We retrieved the Korean literature using a manual search and the English literature using the MEDLINE database concerning the relationship between hypertension and CVD in Koreans from 1980 to 1997. The overall effect size of hypertension as a risk factor of CVD was represented by common odds ratio (OR). Before the integration of each effect size, a heterogeneity test and a sensitivity test was conducted. The materials were nine published epidemiologic studies with a total of 2,271 cases of CVD. The common ORs (95% confidence interval) of overall CVD, hemorrhagic CVD and ischemic CVD associated with hypertension were 4.10 (3.56-4.71), 6.56 (4.92-8.80) and 3.28 (2.77-3.90), respectively. Thus, the common OR of hemorrhagic CVD associated with hypertension was significantly higher than that of overall or ischemic CVD. This suggests that hypertension is an important risk factor for overall CVD and its subtypes in Koreans. Due to the lack of reliable prospective studies, however, longitudinal study is required in this area.

Determination of human angiotensin converting enzyme (ACE) gene polymorphisms in erectile dysfunction: frequency differences of ACE gene polymorphisms according to the method of analysis

The D polymorphism of angiotensin converting enzyme (ACE) gene has been found to be associated with various diseases, and ACE may also be involved in the pathogenesis of erectile dysfunction. On the other hand, interpretation of the data on the association of DD genotype with various diseases is controversial, due to methodological and technical variations in detection of the polymorphisms. We investigated a possible association between the DD genotype and erectile dysfunction in a Korean population, and compared the frequency of ACEgenotypes using our multiplexed PCR method with those based on the conventional PCR method in a sample of erectile dysfunctional and control subjects. There was significant difference in the distribution of ACE genotypes between the erectile dysfunctional (conventional PCR) and the control subjects (multiplexed PCR) (chi2=7.395, p<0.05), but there was no significant difference in the distribution of the genotypes between both groups (chi2=0.815, p>0.05) when our multiplexed PCR method was used. Therefore our results suggest that especially the conventional PCR method for ACE gene polymorphism may require careful control and may need repeated testing to verify the insertion deletion (ID) heterozygotes, and that a multiplexed PCR method can markedly increase the detection rate of the I allele in ID heterozygotes. No association was found between I/D polymorphism and erectile dysfunctional subjects in the Korean population studied.

Intravenous 5-fluorouracil versus oral doxifluridine as preoperative concurrent chemoradiation for locally advanced rectal cancer: prospective randomized trials

BACKGROUND

Preoperative radiation treatment with concomitant intravenous infusion of 5-fluorouracil (5-FU) is known to be effective in shrinking and downstaging of tumors. However, chemotherapy has often been limited by its toxicity and poor patient compliance. Oral 5-FU is known to have several advantages over conventional intravenous 5-FU infusion such as lower toxicity and higher quality of life without compromising the efficacy of the treatment. The aim of this study was to compare intravenous 5-FU with oral doxifluridine with respect to tumor response, toxicity and quality of life.

METHODS

Twenty-eight patients with rectal cancer, staged as over T3N1 or T4 by transrectal ultrasonography between July 1997 and December 1998, were included in this study. Intravenous 5-FU (450 mg/m2) and leucovorin (20 mg/m2) were given for five consecutive days during the first and fifth weeks of radiation therapy (50.4 Gy) (n = 14). Oral doxifluridine (700 mg/m2/day) and leucovorin (20 mg/m2) were given daily during radiation treatment (n = 14). Quality of life was scored according to 22 activity items (good, >77; fair, >58; poor, <57). Surgical resection was performed 4 weeks after completion of concurrent chemoradiation treatment. Tumor response was classified into CR (complete remission), PR (partial response; 50% diminution of tumor volume or downstaging ) and NR (no response).

RESULTS

Tumor response was CR 3/14 (21.4%), PR 7/14 (50%) and NR 4/14 (28.6%) in the IV arm versus CR 2/14 (14.2%), PR 6/14 (42.9%) and NR 6/14 (42.9%) in the Oral arm (p = 0.16, 0.23, 0.24), respectively. The quality of life was poor (36.4% versus 33.3%), fair and good (63.6% versus 66.7%) between the IV arm and Oral arm, respectively. Gastrointestinal toxicity was 2/14 (14.3%) in the IV arm versus 5/14 (35.7%) in the Oral arm, respectively. Stomatitis was only observed in the IV arm (1/14, 7.1%). Hematological toxicity was 3/14 (21.4%) in the IV arm versus 4/14 (28.5%) in the Oral arm, respectively. Systemic recurrence during the follow-up periods were 1/14 (7.1%) in the IV arm and 2/14 (14.3%) in the Oral arm, respectively (p = 0.307). One local recurrence was observed in the Oral arm.

CONCLUSION

Even though the results were not entirely reliable owing to the small number of patients enrolled, oral doxifluridine-based chemotherapy as preoperative chemoradiation for advanced rectal cancer did not show any significant advantages over intravenous infusion.

Repeated exposure to low levels of sulfur dioxide (SO2) enhances the development of ovalbumin-induced asthmatic reactions in guinea pigs

BACKGROUND

Sulfur dioxide (SO2) is one of the major air pollutants. It is known to aggravate asthma symptoms in human beings, but few studies have focused on the effects of SO2 upon the development of bronchial asthma in animal models.

OBJECTIVE

This study was undertaken to evaluate the role of SO2 upon the development of ovalbumin (OA)-induced asthmatic reactions in guinea pigs.

METHODS

Guinea pigs were divided into four groups: (1) OA- and SO2-exposed group (n = 12), (2) SO2-exposed group (n = 12), (3) OA-exposed group (n = 11), and (4) saline-exposed group (n = 7). Guinea pigs of the first and second groups were exposed to 0.1 ppm SO2 for 5 hours a day on 5 consecutive days. Guinea pigs in the first and third groups inhaled 0.1% OA aerosols for 45 minutes a day on days 3, 4, and 5. One week after the sensitization procedure, all the guinea pigs underwent bronchial challenge with 1.0% OA aerosols, using unrestricted whole-body plethysmography. Bronchoalveolar lavage and histopathologic examination were performed 24 hours after the bronchial challenge.

RESULTS

Increases in enhanced pause (Penh), as an index of airway obstruction, after the bronchial challenge was significantly higher in OA- and SO2-exposed group (group 1) than the other groups (P < .05, respectively). Eosinophil counts in bronchoalveolar lavage fluids were also significantly higher in group 1 than in the other groups (P < .05, respectively). Histopathologic findings of bronchial and lung tissue in the group 1 showed an infiltration of inflammatory cells, bronchiolar epithelial damage, and mucus and cell plug in the lumen, but no significant abnormalities were observed in the other groups.

CONCLUSIONS

These results indicate that repeated exposure to low levels of sulfur dioxide may enhance the development of ovalbumin-induced asthmatic reactions in guinea pigs.

Effect of Capsule Circulation Velocity on Production of L-Lysine by Encapsulated Corynebacterium glutamicum in an Airlift Bioreactor

The effect of capsule circulation velocity and volumetric oxygen transfer coefficient on the production of L-lysine by encapsulated Corynebacterium glutamicum in an airlift bioreactor has been evaluated. A larger oxygen supply in the airlift bioreactor caused a more than 58% increase in L-lysine productivity compared to that in a shaking flask incubator. The quantity of L-lysine produced during 5 h of cultivation in the airlift bioreactor was suggested to increase with increasing circulation velocity of the capsule in the bioreactor rather than with an increase in volumetric oxygen transfer coefficient.

Survival of conditionally immortalized hepatocytes in the spleen of syngeneic rats

BACKGROUND

Hepatocyte transplantation has been shown to be effective in the treatment of liver failure; however, the shortage of donor organs limits its clinical application. Several reports have suggested that conditionally immortalized hepatocytes (CIH) could be an alternative to primary hepatocytes. However, CIH are known to undergo apoptosis in vitro at a non-permissive temperature, which is similar to body temperature.

METHODS

To investigate the duration of survival and in vivo apoptosis of CIH in the syngeneic host, the L2A2 cells (a kind of CIH) that were established from hepatocytes of a Lewis rat with a gene for a temperature-sensitive Simian Virus 40 (SV40) large T antigen were transplanted into the spleen. Cells were isolated from the spleen that was removed periodically up to 6 months, and used to detect the presence of the L2A2 cells among them with the selective culture for CIH and T-antigen PCR. In situ apoptosis of L2A2 cells was also examined. In order to improve the survival of transplanted L2A2 cells in the host, a group of rats were partially hepatectomized 1 day before transplantation was performed.

RESULTS

The L2A2 cells secreted albumin at a rate of 1.17 +/- 0.18 microg/24 h per 10(6) cells in vitro. After transplantation, L2A2 cell colonies and PCR amplification bands appeared up to 14 and 7 days, respectively, but this duration was not prolonged by a partial hepatectomy. The spleen showed a large number of hepatocytes that were in the process of dying on the 5th day, and only a number of ghost hepatocytes were present on the 7th day of transplantation. No tumors were found during the 6-month observation period.

CONCLUSIONS

Conditionally immortalized hepatocytes can survive in the spleen for a limited period, in spite of the growth stimulation, most likely because they undergo apoptosis in vivo as well as in vitro at a non-permissive temperature. These data suggest that the use of these cells in hepatocyte transplantation be limited to temporary hepatic support.

Preoperative staging of rectal cancer with MRI: accuracy and clinical usefulness

BACKGROUND

Preoperative staging is essential for planning of optimal therapy for patients with rectal cancer. Recently, magnetic resonance imaging (MRI) is used frequently because of its benefits of clear pelvic image are better than other diagnostic methods. The purpose of this study was to determine accuracy rates and clinical usefulness of MRI in preoperative staging of rectal cancer.

METHODS

Between February, 1997, and December, 1999, 217 patients with histologically proven rectal cancer were staged preoperatively and had surgical resections performed. MRI criteria for depth of invasion was determined by the degree of disruption of the rectal wall. Metastatic perirectal lymph nodes were considered to be present if they showed heterogenous texture, irregular margin, and enlargement (>10 mm).

RESULTS

The accuracy of the MRI for determining depth of invasion was 176/217 (81%) and regional lymph node invasion was 110/217 (63%). In the T stage, accuracy rate of T1 was 3/4 (75%), T2 was 20/37 (54%), T3 was 141/162 (87%), and T4 was 12/14 (86%), respectively. The specificity of lymph node invasion was 45/110 (41%) and the sensitivity was 91/107 (85%). The accuracy rate of regional lymph node involvement was 136/217 (63%). T1 and T2 were overstaged in 1/4 (25%) and 17/37 (46%), respectively, and T3 was understaged in 15/162 (9.2%). The accuracy rate to detect metastatic lateral pelvic lymph node was 4/14 (29%) after lateral pelvic lymph node dissection was done in 14 patients under MRI. The accuracy rate in assessing levator ani muscle tumor involvement was 8/11 (72%).

CONCLUSIONS

MRI showed a good, comparable accuracy rate for determining depth of tumor invasion, compared with transrectal ultrasonography, which still has a low accuracy rate for detecting metastatic lymph node. MRI with endorectal coil may increase the accuracy rate of T1 and T2 lesions. In addition, clear sagittal and coronal sectional pelvic images can give a lot of information about adjacent organ invasion or any invasion of levator ani muscle. MRI can be useful for choosing an appropriate extent of lymph node dissection and type of surgery.

Ischemia-reperfusion injury in renal transplantation is independent of the immunologic background

BACKGROUND

Adhesion molecule expression is important to early transplant failure. However, whether or not adhesion molecule-facilitated inflammation is antigen-dependent is unknown. We tested this hypothesis.

METHODS

Rat renal grafts were four-hours cold-preserved in University of Wisconsin (UW) solution, transplanted to syngeneic or allogeneic recipients, and harvested after 2, 6, 12, 24, and 48 hours and after 1 week. The first allogeneic group receive no immunosuppression; two additional groups received either low (1.5 mg/kg) or standard (5 mg/kg) cyclosporine A (CsA). Renal function and morphology were determined; frozen sections were immunostained for P-selectin, L-selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), platelet endothelial cell adhesion molecule-1 (PECAM-1), leukocyte function associated molecule-1 (LFA-1), very late antigen-4 (VLA-4), as well as for neutrophils and monocytes.

RESULTS

Selectins increased rapidly at 2 hours and quickly decreased by 12 hours. While P-selectin was expressed on vasculature, L-selectin was found on inflammatory cells. Neutrophil influx and that of LFA-1-positive cells occurred early, peaked between 12 and 24 hours, and paralleled the maximal impairment in renal function. ICAM-1 and PECAM-1 showed similar kinetics and a diffuse distribution. VCAM-1 increased more slowly after 12 hours, peaked at 24 hours, and was localized predominantly on the endothelium of elastic vessels. Between 24 hours and 1 week, all grafts progressively developed dense VLA-4-positive monocytic infiltrates adjacent to vessels expressing VCAM-1. Functional, morphological, and immunohistochemical parameters did not differ between isografts and allografts at one week. However, by day 10, allografts showed severe vascular and cellular rejection, while injury in isografts resolved. Immunosuppression with CsA did not reverse the inflammation induced by ischemia-reperfusion injury.

CONCLUSIONS

The early inflammation after ischemia-reperfusion injury is largely independent of the immunologic background. We suggest that initial injury prevention should receive the highest priority.

Chitin catabolism in the marine bacterium Vibrio furnissii. Identification, molecular cloning, and characterization of A N, N'-diacetylchitobiose phosphorylase

The major product of bacterial chitinases is N,N'-diacetylchitobiose or (GlcNAc)(2). We have previously demonstrated that (GlcNAc)(2) is taken up unchanged by a specific permease in Vibrio furnissii (unlike Escherichia coli). It is generally held that marine Vibrios further metabolize cytoplasmic (GlcNAc)(2) by hydrolyzing it to two GlcNAcs (i.e. a "chitobiase "). Here we report instead that V. furnissii expresses a novel phosphorylase. The gene, chbP, was cloned into E. coli; the enzyme, ChbP, was purified to apparent homogeneity, and characterized kinetically. The DNA sequence indicates that chbP encodes an 89-kDa protein. The enzymatic reaction was characterized as follows. (GlcNAc)(2)+P(i) GlcNAc-alpha-1-P+GlcNAc K'(cq)=1.0+/-0.2 Reaction 1 The K(m) values for the four substrates were in the range 0.3-1 mm. p-Nitrophenyl-(GlcNAc)(2) was cleaved at 8.5% the rate of (GlcNAc)(2), and p-nitrophenyl (PNP)-GlcNAc was 36% as active as GlcNAc in the reverse direction. All other compounds tested displayed </=1% of the activity of the indicated substrates including: for phosphorolysis, higher chitin oliogsaccharides, (GlcNAc)(n), n = 3-5, cellobiose, PNP-GlcNAc, and PNP-(GlcNAc)(3); for synthesis, (GlcNAc)(n) (n = 2-5), glucose, etc. (GlcNAc)(2) is a major regulator of the chitin catabolic cascade. Conceivably GlcNAc-alpha-1-P plays a similar but different role in regulation.