Lack of association between COPD and transforming growth factor-beta1 (TGFB1) genetic polymorphisms in Koreans

OBJECTIVE

Many genetic variations have been suggested as genetic risk factors for the development of chronic obstructive pulmonary disease (COPD), including single nucleotide polymorphisms in the transforming growth factor-beta1 (TGFB1) gene. We attempted to elucidate the association between TGFB1 genetic polymorphisms and COPD among Koreans.

DESIGN

The genotypes of 102 male patients with COPD and 159 volunteers with similar distributions of age, sex and smoking intensity, as well as normal pulmonary function, were determined for three previously associated TGFB1 single nucleotide polymorphisms (SNPs), -10807G/A (rs2241712) and -509T/C (rs1800469), located in or near the promoter, and 29T/C (rs1982073), located in exon 1 of the TGFB1 gene.

RESULTS

No significant associations between COPD and the three TGFB1 SNPs could be identified. In addition, the haplotypes composed of three TGFB1 SNPs were not associated with the presence of COPD.

CONCLUSION

These results differ from previous reports involving Caucasians, and might reflect racial differences in the pathogenesis of COPD.

The association between microsatellite polymorphisms in intron II of the human Toll-like receptor 2 gene and tuberculosis among Koreans

The observation that Toll-like receptor (TLR)2-deficient mice are highly susceptible to mycobacteria suggests that mutations altering TLR2 expression may impair host response to Mycobacterium tuberculosis. We evaluated the association between guanine-thymine (GT) repeat polymorphism in intron II of the TLR2 gene and the presence of tuberculosis (TB) in Koreans. The numbers of GT repeats were determined by PCR and gene scans for 176 TB patients and 196 controls. The recombinant TLR2 promoter/exonI/exonII/intronII/luciferase constructs including three representative repeats: (GT)13, (GT)20, and (GT)24 were transfected into K562 cells, and luciferase activities were estimated and compared. The expression of TLR2 on CD14+ peripheral blood mononuclear cells (PBMC) from healthy volunteers were measured with flow cytometry. Genotypes with shorter GT repeats were more common among TB patients (49.4 vs 37.7%, P=0.02). This observation was confirmed among 82 other TB patients as a validation cohort. Shorter GT repeats were associated with weaker promoter activities and lower TLR2 expression on CD14+ PBMCs. In conclusion, the development of TB disease in Koreans was associated with shorter GT repeats in intron II of the TLR2 gene. This association is correlated with lower expression of TLR2 through weaker promoter activity for genes with shorter GT repeats.

Surgical treatment for congenital arteriovenous malformation: 10 years' experience

OBJECTIVES

We report our 10 years experience of the surgical treatment of congenital arteriovenous malformation (AVM).

METHODS

We retrospectively reviewed the medical records of 145 patients with AVM who visited Samsung Medical Center in Korea from 1994 to 2003. Among the 145 patients, 21 patients were operated on. Preoperative embolo/sclerotherapy was done in 20 out of the 21 patients.

RESULTS

The surgically treated AVMs were 13 cases of head and neck lesions, four cases of upper extremity lesions, one case each of back lesion, uterus lesion, lower extremity lesion and multiple site lesions. There were 10 patients with the extratruncular infiltrating type, nine patients with the extratruncular limited type, one patient with a truncular superficial AV fistula and one patient with a mixed type. Fourteen cases were operated on for cosmetic reasons and since they had localized lesions, and five cases were operated on for tissue necrosis. Fourteen cases were cured by a single operation, yet seven cases needed several sessions of operation to cure the AVM or to promote wound healing after surgery.

CONCLUSION

The surgical treatment of AVM is a challenging issue for vascular surgeons. To minimise the complications related to surgery, a multidisciplinary team approach should be considered.

The study of cerebral hemodynamics in the hyperacute stage of fat embolism induced by triolein emulsion

PURPOSE

The purpose of this study was to evaluate the cerebral hemodynamic change in the hyperacute stage of cerebral fat embolism induced by triolein emulsion, by using MR perfusion imaging in cat brains.

METHODS

By using the femoral arterial approach, the internal carotid arteries of 14 cats were infused with an emulsion of triolein 0.05 mL. T2-weighted (T2WI), diffusion-weighted (DWI), apparent diffusion coefficient (ADC) map, perfusion-weighted (PWI), and gadolinium-enhanced T1-weighted (Gd-T1WI) images were obtained serially at 30 minutes and 2, 4, and 6 hours after infusion. The MR images were evaluated qualitatively and quantitatively. Qualitative evaluation was performed by assessing the signal intensity of the serial MR images. Quantitative assessment was performed by comparing the signal-intensity ratio (SIR) of the lesions to the contralateral normal side calculated on T2WIs, Gd-T1WIs, DWIs, and ADC maps at each acquisition time and by comparing the relative cerebral blood volume (rCBV), cerebral blood flow (CBF), and mean transit times (MTT) of the lesions to the contralateral normal side calculated on PWI.

RESULTS

In the qualitative evaluation of the MR images, the lesions showed hyperintensity on T2WIs, enhancement on the Gd-T1WIs, and isointensity on DWIs and the ADC maps. In the quantitative studies, SIRs on the Gd-T1WIs, DWIs, and ADC maps peaked at 2 hours after infusion. The SIRs on the T2WIs peaked at 4 hours after infusion and decreased thereafter. On PWIs, the rCBV, rCBF, and MTT of the lesion showed no significant difference from the contralateral normal side (P = .09, .30, and .13, respectively) and showed no significant change of time course (P = .17, .31, and .66, respectively).

CONCLUSION

The embolized lesions induced by triolein emulsion showed no significant difference in cerebral hemodynamic parameters from those on the contralateral normal side. The result may suggest that consideration of the hemodynamic factor of embolized lesions is not necessary in further studies of the blood-brain barrier with triolein emulsion.

Comparative study of the subserosal versus submucosal dye injection method for sentinel node biopsy in gastric cancer

AIMS

To determine the most efficient injection method for a sentinel node (SN) biopsy in gastric cancer.

METHODS

Gastric adenocarcinoma patients without serosal invasion and distant metastasis were prospectively enrolled in this study. Isosulfan blue was injected into the subserosa (SS) of the first set of 71 consecutive patients and an intraoperative endoscopic submucosal (SM) injection of the same dye was injected into the second set of 50 consecutive patients. After the biopsy of blue-stained SNs, a gastrectomy with a D2 lymphadenectomy was performed. All dissected lymph nodes were evaluated for metastasis. The results of the SN biopsies were compared between the SS and SM dye injection methods.

RESULTS

Detection rate (0.92 vs 0.94), mean number of SNs (2.5 vs 2.9) and sensitivity (0.61 vs 0.46) of the SN biopsies were not significantly different between the SS and SM injection methods (P>0.05). The operation time was significantly shorter in the SS than the SM injection method (159.7 vs 172.7 min, P=0.030).

CONCLUSIONS

Both injection methods were equally efficient in their roles for a SN biopsy in gastric cancer. However, the SS injection method was more preferable due to its easy technique and short operation time.

Development of anticancer gene vaccine interact with human papillomavirus oncoprotein inhibition

Adeno-associated virus (AAV) Rep 78 protein is known to inhibit the promoter site of several oncogenes and viral genes, including the human papillomavirus (HPV) type 16 E6 transforming genes. The biochemical studies of Rep 78 have been reported, but the effects of Rep 78 gene-mediated inhibition of HPV 16 E6 promoter activity on the various human cervical carcinoma cells have not been characterized. pEGFP-N1 vector, cloned by AAV-mediated Rep 78, is transfected into cervical carcinoma cells. Transfection efficiency of Rep 78 was approximately 30-60% different. Messenger RNA (mRNA) and protein expression of Rep 78 gene was significantly higher on day 1 of the transfection of Rep 78 DNA in CaSki cells, and DNA level of HPV 16 E6 was decreased on day 1 of the transfection. The growth of CaSki cervical cancer cells was only 10-15% inhibited by Rep 78, and the other cervical cells, HeLa, HeLaS3, HT3, and QGU, were unaffected by Rep 78 transfection. In spite of the high efficiency of Rep 78 gene transformation and expression rate, we could not show the significant growth inhibition in various cervical cancer cell lines. Taken together, long-term expression of Rep 78 strategy might be needed for cervical carcinoma gene therapy using AAV vector.

Effect of leptin on insulin resistance of muscle – direct or indirect?

We examined the effect of leptin on the insulin resistance in skeletal muscles by measuring glucose transport. Male Wistar rats were fed rat chow or high-fat diets for 30 days. Before sacrifice, rats fed high-fat diet were subcutaneously injected with leptin (1 mg/kg b.w.) for 3 days. The glucose transport in epitrochlearis and soleus muscles did not differ in the experimental groups under basal conditions, however these values decreased significantly in the rats fed high-fat diet under insulin stimulation (p<0.01). Leptin treatment recovered the decreased glucose transport in epitrochlearis (p<0.05) and soleus muscles (p=0.08). Triglyceride concentrations in soleus muscles were increased significantly in the rats fed high-fat diet as compared to rats fed chow diet (p<0.01), and were decreased significantly by leptin treatment (p<0.01). The glucose transport was measured under basal conditions and after 60 microU/ml of insulin treatment with or without 50 ng/ml of leptin. Leptin had no direct stimulatory effect on glucose transport under both basal and insulin-stimulated conditions in vitro. These results demonstrate that leptin injection to rats fed high-fat diet recovered impaired insulin responsiveness of skeletal muscles and muscle triglyceride concentrations. However, there was no direct stimulatory effect of leptin on insulin sensitivity of skeletal muscles in vitro.

Impact of fluoroquinolones on the diagnosis of pulmonary tuberculosis initially treated as bacterial pneumonia

OBJECTIVE

The excellent in vitro activity of fluoroquinolones against Mycobacterium tuberculosis has raised concerns about the delayed diagnosis of pulmonary tuberculosis (PTB) initially misdiagnosed as pneumonia. The aim of this study was to assess the effect of empiric fluoroquinolone therapy on delays in diagnosis in patients with PTB initially misdiagnosed as bacterial pneumonia.

DESIGN

Patients with PTB initially treated as having community-acquired pneumonia and treated with fluoroquinolones for more than 5 consecutive days, from January 2000 to December 2004, were enrolled. As a control group, TB patients initially treated with nonfluoroquinolone antibiotics were enrolled. We reviewed the clinical data and compared treatment responses between the two groups.

RESULTS

Nine patients in the fluoroquinolone group and 19 patients in the non-fluoroquinolone group were enrolled. In the fluoroquinolone group, eight patients (89%) improved clinically or radiographically, whereas only eight patients (42%) in the non-fluoroquinolone group improved (P = 0.04). The delay in initiation of anti-tuberculosis medication was longer in the fluoroquinolone group than in the non-fluoroquinolone group (43.1 - 40.0 vs. 18.7 +/- 16.9 days, P = 0.04).

CONCLUSION

Delay in the initiation of anti-tuberculosis treatment is possible in patients administered fluoroquinolone and initially misdiagnosed as having bacterial pneumonia.

Factors Affecting the Long-term Patency of Crossover Femorofemoral Bypass Graft

OBJECTIVES

To determine the factors affecting long-term patency of crossover femorofemoral bypass (FFB) graft.

DESIGN

A retrospective clinical study of a prospectively registered database.

MATERIALS

Two hundred and sixteen FFBs performed for 192 patients with atherosclerotic iliac occlusive disease.

METHODS

The clinical and surgical variables influencing graft patency were assessed with log-rank test and Cox's proportional hazard analysis.

RESULTS

The primary patency rates of all FFB grafts at 3 and 5 years were 73+/-4 and 65+/-5%, respectively. By multivariate analysis, hypertension (Odds ratio 2.8, P=0.002) and critical ischemia (Odds ratio 0.42, P=0.01) significantly (P<.05) influenced long-term patency of FFB grafts.

CONCLUSION

The long-term patency of FFB grafts was not affected by procedural modifications. Graft patency was inferior in patients with severe lower limb ischemia but superior in patients with hypertension. Further study is required to clarify the mechanism of an unexpected beneficial effect of hypertension on FFB graft patency.

Advanced management of arteriovenous shunting malformation with transarterial lung perfusion scintigraphy for follow-up assessment

AIM

The clinical assessment of arteriovenous malformations (AVMs), including treatment response (surgical and/or embolosclerotherapy), has traditionally been done by arteriography, mainly by looking for residual lesions. However, arteriography is disadvantaged as it is an expensive invasive test with high morbidity and provides only limited anatomical information at the qualitative level. Here, transarterial lung perfusion scintigraphy (TLPS), which was developed as a less invasive test for the physiologic assessment of the arteriovenous shunting status of AVM lesions located in the lower extremities, was evaluated for its ability to replace traditional arteriography as a means of following-up treatment results.

METHODS

The shunting volume of radioisotope-tagged macro-aggregated albumin injected into the arterial system of the affected limb was counted by TLPS before and after AVM treatment, as a quantitative measure of treatment response. The findings obtained were compared with a matching duplex scan, whole body blood pool scintigraphy (WBBPS) findings, and arteriographic findings.

RESULTS

Twenty-one TLPS tests were performed as follow-up assessments on 15 patients with AVM in the extremity, who underwent multistaged embolo/sclerotherapy alone or combined with surgical therapy. These 21 TLPS findings, including 6 interim TLPS results (average 16 months follow-up), provided quantitative measurements of lesion reductions as percentile ratios versus the baseline pretreatment values. Matching posttreatment duplex scan (14 out of 17 sets) and WBBPS (12 out of 15 sets) findings confirmed the posttreatment TLPS assessment.

RESULTS

In addition, all 12 available arteriographic studies confirmed the matching TLPS findings.

CONCLUSIONS

TLPS can provide accurate information on shunting volume reduction, occurring in response to various treatments during or after the completion of therapy. TLPS, therefore, may be able to replace arteriography, and provide a reliable means of follow-up assessment for the determination of the future treatment strategy.

Oral insertion of a flexible bronchoscope is associated with less discomfort than nasal insertion for Korean patients

OBJECTIVE

The route of bronchoscope insertion varies between centres, without a firm rationale based on well-designed studies. We therefore compared nasal and oral insertion of a flexible bronchoscope and evaluated efficacy and patient satisfaction.

DESIGN

Prospective randomised study of patients who underwent flexible bronchoscopy from May to September 2003 and who were randomly assigned to nasal and oral insertion approaches.

RESULTS

Clinical characteristics, factors related to the procedure and patient satisfaction were analysed. In total, 307 patients were randomly assigned to the nasal (n = 158) or oral insertion groups (n = 149). No difference in baseline characteristics was identified between the groups. Insertion by the oral route was associated with a smaller amount of lidocaine use during the procedure (P = 0.04) and less frequent insertion site bleeding (P = 0.005). Patients assigned to oral insertion reported less discomfort during anaesthesia (P = 0.01) and scope insertion (P < 0.001), as well as less dyspnoea (P = 0.04) and coughing (P = 0.03).

CONCLUSION

Oral insertion of a flexible bronchoscope was associated with less discomfort for patients than nasal insertion, although the route of insertion had no significant effect on outcome.

Contemporary diagnosis and management of venous and arterio-venous shunting malformation by whole body blood pool scintigraphy

AIM

Various non- to less-invasive tests have been recently introduced in the management of congenital vascular malformations (CVM) and have become essential for the initial diagnostic work-up, largely replacing the traditional role of invasive tests. Whole body blood pool scintigraphy (WBBPS) was initially adopted as a supplementary test to reinforce other well-established essential diagnostic tests, and has been used extensively together in our Clinic, for years. We have evaluated WBBPS retrospectively for the diagnosis of venous malformation (VM) and arterio-venous malformation (AVM), and also for a further possible role for the interim assessment of treatment results during multistaged embolo/sclerotherapy.

METHODS

Of 123 VMs and 48 AVMs selected for various treatments, 80 patients (66 VMs and 14 AVMs) were reviewed. The reliability of WBBPS as an initial diagnostic tool for VMs and AVM was assessed first by comparing its findings with matching MRI and/or duplex scan findings. These 80 patients underwent embolo/sclerotherapy with absolute ethanol mostly for VM, and N-butyl cyanoacrylate for AVM. A total of 251 sessions were performed either as a primary treatment independently or in conjunction with surgical treatment preoperatively. Thirty-six patients were available in terms of the subsequent review of the treatment results, to compare their 72 post-therapy WBBPS findings with matching duplex scan and MRI findings. The WBBPS assessment of treatment response was based on the percentage reduction of abnormal blood pooling over the region of interest (ROI) from baseline (initial) value. Treatment response was also qualitatively and semi-quantitatively assessed according to the degree of abnormal blood pool reduction.

RESULTS

Of the 80 CVM (66 VM and 14 AVM) patients, 61 of 66 WBBPS findings of VM on initial diagnosis were confirmed as true-positive. Twelve of 14 AVMs were also confirmed as WBBPS true-positive findings. The sensitivity of WBBPS for the initial diagnosis was 93.8% (61/65) for VM and 92.3% (12/13) for AVM. The positive predictive value was 98.4% (61/62) for VM and 92.3% (12/13) for AVM. Of 72 post-therapy WBBPS performed for follow-up assessment of the results of treatment on 36 patients, 52 WBBPS showed positive findings qualitatively and/or quantitatively, the remaining 20 were negative. Fifty-one of the 52 WBBPS-positive findings were true-positive and 18 of the 20 were true-negative. Hence, WBBPS for follow-up assessment showed a sensitivity of 96% (51/53); a specificity of 95% (18/19); a positive predictive value of 98% (51/52); and a negative predictive value of 90% (18/20).

CONCLUSIONS

Contemporary management of CVMs can be improved by using WBBPS, which is a less expensive, simple, and safe non-invasive test, especially for venous and arterio-venous malformations. WBBPS is a cost-effective and practical test with dependable accuracy for the assessment of treatment results, especially for interim measurements during multistage embolo/sclerotherapy.

The role of hand-assisted laparoscopic distal gastrectomy for distal gastric cancer

BACKGROUND

The aim of this study was to evaluate the role of hand-assisted distal gastrectomy (HALDG) for gastric cancer.

METHODS

This study prospectively enrolled 16 patients who underwent HALDG for early gastric cancer and matched them individually by sex, age, and body mass index to patients who underwent laparoscopically assisted distal gastrectomy (LADG) or open distal gastrectomy (ODG). Surgical outcomes were compared among the surgical methods.

RESULTS

The mean operating time was the longest for the HALDG group, whereas wound size of the HALDG group was intermediate between that of the LADG and the ODG groups. The other surgical outcomes, such as the number of harvested lymph nodes, were not different among the groups.

CONCLUSIONS

According to the findings, HALDG may not be as beneficial for patients with early gastric cancer as has been previously suggested. However, because of easier hand-eye coordination, HALDG may be an excellent bridge learning technique as a surgeon gains experience in laparoscopic gastrectomy.

Effect of TCDD on corpus cavernosum histology and smooth muscle physiology

A polyhalogenated aromatic hydrocarbon, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is one of the most potent toxic environmental pollutants. Decreases in spermatogenesis and the ability to conceive and carry a pregnancy to term are the most sensitive signs of reproductive toxicity by TCDD in the mammal, but no report of its effect on the erectile function exists. We performed this study to investigate the effect of TCDD on the erectile function. New Zealand white rabbits were treated intraperitoneally with 1 microg/kg of TCDD. At 4 (Gr I) and 8 (Gr II) weeks after the administration of TCDD, cavernosal tissues were harvested for strip study in the organ bath and testes were prepared for histologic examination. Compared to the maximal amplitude of 17.1+/-4.12 mN in normal control (Gr III), the contractions to cumulative concentrations of NE (10(-8)-10(-4) M) were significantly decreased to 6.57+/-1.34 and 5.45+/-1.01 mN in Groups I and II, respectively. Compared to 51.12+/-7.38% in Gr III, relaxation to cumulative concentration (10(-8)-10(-4) M) of acetylcholine was significantly decreased to 17.25+/-2.17% (Gr I) and 9.73+/-2.17% (Gr II) at a concentration of 10(-4) M, respectively. Compared to 75.12+/-13.18% in Gr III, relaxation to cumulative concentration (10(-8)-10(-4) M) of SNP was significantly decreased to 31.49+/-7.89% (Gr I) and 18.54+/-6.12% (Gr II) at a concentration of 10(-4) M, respectively. Histologically, intracavernosal fibrosis, abnormal subtunical deposition of fat and decreased sinusoidal space with consequent increase of trabecular smooth muscle contents were identified in TCDD-treated groups. In TCDD-treated animals, seminiferous tubules showed a decrease of germ cells with vacuolar degeneration and apoptotic cells. Spermatids were hardly seen. These results suggest that TCDD inhibits spermatogenesis and has a potential harmful effect on erectile function via changes of corpus cavernosum histology and smooth muscle physiology.

Response of pulmonary tuberculomas to anti-tuberculous treatment

Pulmonary tuberculomas are well-circumscribed masses caused by Mycobacterium tuberculosis. However, the response of tuberculomas to anti-tuberculous (TB) treatment has not been well defined as yet. The response of pulmonary tuberculomas to anti-TB treatment was retrospectively reviewed in 45 patients diagnosed between January 1997 and December 2001. The areas of pulmonary tuberculomas were estimated by calculating products of the longest and their perpendicular short diameters on chest radiographs. The response to anti-TB treatment was categorised as "decreased" (> 25% reduction in area versus its initial area), "increased" (> 251% increase) and "no change" (the remainder). The mean of treatment duration was 11.5 +/- 3.6 months. Three months after treatment, 18 patients (40.0%) were categorised as decreased, 25 (55.6%) as no change and two (4.4%) as increased. Twelve months after treatment, out of 42 patients available for chest radiographs, 32 patients (76.2%) were categorised as decreased, nine (21.4%) as no change and one patient (2.4%) as increased. At the last follow-up (mean follow-up 27.0 +/- 10.2 months), 37 patients (82.2%) were categorised as decreased. The majority of pulmonary tuberculomas were decreased by anti-tuberculosis treatment during and even after treatment, although a transient enlargement during the early period of treatment was observed infrequently.

Prediction of lymph nodes metastasis by sentinel node biopsy in gastric cancer

AIM

The application of sentinel node (SN) biopsy in gastric cancer remains controversial. In this study, detection rate and predictive values of SN biopsy were determined to evaluate its feasibility in gastric cancer. Various clinicopathologic features were also analysed to determine the factors affecting the detection rate and predictive values.

METHODS

Seventy-one gastric adenocarcinoma patients without serosal invasion and distant metastasis, were studied. One percent isosulfan blue stained nodes were defined as SNs, and standard gastrectomy with D2 lymphadenectomy was performed. All lymph nodes were studied by hematoxylin and eosin staining.

RESULTS

SNs were identified in 65 of 71 patients and average number of SNs per patient was 2.5 (range 1-8). Among the 65 patients with SNs, metastatic SNs were found in 11 and the remaining 54 were free of metastasis. In eight of the 11 patients with metastasis of the SNs, metastases were also identified in non-SNs.

CONCLUSIONS

SN biopsy is feasible in early stage gastric cancer. However, complementary procedures may be needed to improve the detection rate and predictive values. SNs biopsy results should be treated with caution in male patients and for tumours at the upper part of stomach due to the low detection rate.

Two cases of steakhouse syndrome associated with nutcracker esophagus

The most common type of esophageal food-related foreign body is the meat bolus, which is frequently associated with underlying esophageal stenosis. Herein, we report two cases of meat bolus impaction associated with nutcracker esophagus. In the first case, the 63-year-old male patient had chest discomfort and swallowing difficulty after ingestion of butcher's meat. In the second case, the 55-year-old male patient had complained of swallowing difficulty after ingestion of chicken. In both cases, no pathologic findings were observed endoscopically after removal of the esophageal meat bolus. We performed esophageal manometry, which showed very high amplitudes of esophageal pressure in the mid- and distal esophagus. These findings were consistent with nutcracker esophagus. These cases show that esophageal motility disorder may be the cause of esophageal foreign body impaction, and esophageal manometry should be performed for evaluation of the cause of foreign body, especially in an endoscopically normal patient.

Lack of association between glutathione S-transferase P1 polymorphism and COPD in Koreans

The fact that only 10-20% of chronic heavy cigarette smokers develop symptomatic COPD and correlations of pulmonary function among twins and families suggests the presence of genetic susceptibility in the development of COPD. Genetic susceptibility to COPD might depend on the variations in enzyme activities that detoxify cigarette smoke products, such as microsomal epoxide hydrolase (mEPHX) and glutathione-S transferase (GST). The purpose of this study was to determine whether polymorphism of GSTP1 gene is linked to a genetic susceptibility to COPD. The hypothesis we tested here was that the polymorphism supposed to decrease GSTP1 activity would be the genetic risk for the development of COPD. Using PCR followed by restriction fragment length polymorphism (PCR-RFLP), genotypes of Ile105Val polymorphism in exon 5 of glutathione S-transferase P1 (GSTP1) gene were determined in 89 patients with COPD and 94 healthy smoking control subjects at the Seoul National University Hospital. Although the frequency of homozygous wild allele in exon 5 of GSTP1 gene in patients with COPD was higher than that observed in healthy controls (71% vs. 61%), the difference was not considered statistically significant. Neither the heterozygous nor homozygous mutant allele differed in frequency between the two groups. In conclusion, the genetic polymorphisms of exon 5 of GSTP1 gene may not be associated with development of COPD in Koreans.

The response to iron deprivation in Saccharomyces cerevisiae: expression of siderophore-based systems of iron uptake

The budding yeast Saccharomyces cerevisiae responds to growth in limiting amounts of iron by activating the transcription factor Aft1p and expressing a set of genes that ameliorate the effects of iron deprivation. Analysis of iron-regulated gene expression using cDNA microarrays has revealed the set of genes controlled by iron and Aft1p. Many of these genes are involved in the uptake of siderophore-bound iron from the environment. One family of genes, FIT1, FIT2 and FIT3, codes for mannoproteins that are incorporated into the cell wall via glycosylphosphatidylinositol anchors. These genes are involved in the retention of siderophore-iron in the cell wall. Siderophore-bound iron can be taken up into the cell via two genetically separable systems. One system requires the reduction and release of the iron from the siderophore prior to uptake by members of the Fre family of plasma-membrane metalloreductases. Following reduction and release from the siderophore, the iron is then taken up via the high-affinity ferrous transport system. A set of transporters that specifically recognizes siderophore-iron chelates is also expressed under conditions of iron deprivation. These transporters, encoded by ARN1, ARN2/TAF1, ARN3/SIT1 and ARN4/ENB1, facilitate the uptake of both hydroxamate- and catecholate-type siderophores. The Arn transporters are expressed in intracellular vesicles that correspond to the endosomal compartment, which suggests that intracellular trafficking of the siderophore and/or its transporter may be important for uptake.

Malignant mixed müllerian tumor of the ovary: imaging findings

OBJECTIVE

We describe the imaging findings of malignant mixed müllerian tumor (MMMT) of the ovary, which have not previously been reported.

MATERIALS AND METHODS

We experienced 13 cases of ovarian MMMT in eight patients. All patients underwent surgical resection and the MMMTs were confirmed pathologically. US (n = 8), CT (n = 8), and MRI (n = 1) examinations were performed before operation. Imaging features were analyzed retrospectively for bilaterality, tumor solidity (cystic or solid), size, and contrast enhancement of the tumor on CT and MRI. Presence of ascites and other evidence of peritoneal seeding, adjacent organ invasion, distant metastasis, and surgical staging were also evaluated.

RESULTS

There were bilateral ovarian MMMTs in five patients and unilateral MMMTs in three patients. Two of the MMMTs were multiseptated cystic, and 11 were mixed (solid and cystic). The diameter of the largest dimension was less than 5 cm in one case, 5-10 cm in two cases, and larger than 10 cm in 10 cases. Dense homogeneous contrast enhancement of the solid component was seen in 11 mixed masses. Ascites were found in all patients. Other evidence of peritoneal seeding and direct invasion into adjacent organ such as the uterus or sigmoid colon was seen in five patients each. Pleural metastasis was present in one patient. Surgical stages were FIGO classification IIIb and IV in one patient each, and IIIc in six patients.

CONCLUSION

Ovarian MMMTs usually present as aggressive, bilateral, large, solid and cystic tumors, combined with ascites, frequent peritoneal seeding, and adjacent organ invasion.

Hydraulic properties and leachate level analysis of Kimpo metropolitan landfill, Korea

Hydraulic properties of waste and cover soil from Kimpo Metropolitan Landfill were experimentally measured by laboratory tests. The degree of compaction was changed to identify the effect on hydraulic conductivity, field capacity, and permanent wilting point. Properties were utilized in developing a reliable numerical tool for leachate analysis. HELP, a simulation model for hydrologic evaluation of landfill performance, was adopted for that purpose. For calibration, results from simulation using the parameter values measured by laboratory tests were compared against the field data. The model was applied to predict the leachate level change according to the degree of compaction and cover soil thickness variation. It was found that the increase in the degree of compaction for intermediate cover soil and waste results in the decrease of field capacity and hydraulic conductivity, hence, the increase of leachate level. The effect of cover layer thickness on the leachate level was minor. Based on the findings from laboratory and numerical experiments, a guideline for reclamation practice was recommended.

Clinical significance of urinary vascular endothelial growth factor and microvessel density in patients with renal cell carcinoma

OBJECTIVES

To investigate the urinary vascular endothelial growth factor (VEGF) levels from patients with renal cell carcinoma (RCC). Neovascularization, an essential event for the growth of solid tumors, is regulated by a number of angiogenic factors. VEGF is thought to exert potent angiogenic activity.

METHODS

Urine samples were obtained before radical nephrectomy from 27 patients with RCC and 10 control subjects with no evidence of cancer or inflammatory disease. VEGF was measured by enzyme-linked immunosorbent assay in the urine and corrected according to the 24-hour urine concentration of creatinine. The microvessel density was measured by immunohistochemical staining with CD31 monoclonal antibody. Nuclear morphometry was performed by photomicroscopy.

RESULTS

The corrected urinary VEGF levels in patients with RCC were much higher than those in the normal control group (P = 0.039) and were more elevated in patients with higher stages of RCC (Stages III and IV versus Stages I and II; P = 0.024). A tendency was also noted for the VEGF levels to be higher according to cell grade. However, no statistical correlation was found between the corrected urinary VEGF and age, sex, tumor size, cell type, microvessel density, platelet count, or hemoglobin. The nuclear area was higher with more advanced-stage tumors (P = 0.043) and tended to increase according to the tumor cell grade.

CONCLUSIONS

The results of this study indicate that urinary VEGF levels are increased in patients with RCC. However, they may not reflect the underlying angiogenic activity, and it may be that other angiogenic factors play a more prominent role.

Modulation of the multisubstrate specificity of Thermus maltogenic amylase by truncation of the N-terminal domain and by a salt-induced shift of the monomer/dimer equilibrium

The relation between the quaternary structure and the substrate specificity of Thermus maltogenic amylase (ThMA) has been investigated. Sedimentation diffusion equilibrium ultracentrifugation and gel filtration analyses, in combination with the crystal structure determined recently, have demonstrated that ThMA existed in a monomer/dimer equilibrium. The truncation of ThMA by removing the N-terminal domain, which is composed of 124 amino acid residues, resulted in the complete monomerization of the enzyme (ThMADelta124) accompanied by a drastic decrease in the activity for beta-cyclodextrin (beta-CD) and a relatively smaller reduction of the activity for starch. Despite the overall low activity of ThMADelta124, the activity was higher toward starch than beta-CD, and the ratio of the specific activities toward these substrates was approximately 100 fold higher than that of wild-type ThMA. Furthermore, the addition of KCl to wild-type ThMA shifted the monomer/dimer equilibrium toward the monomer. In the presence of 1.0 M KCl, the relative activity of ThMA toward beta-CD decreased to 74%, while that for soluble starch increased to 194% compared to the activities in the absence of KCl. Thus, the ThMA monomer and dimer are both inferred to be enzymatically active but with a somewhat different substrate preference. Kinetic parameters of the wild-type and truncated enzymes also are in accordance with the changes in their specific activities. We thus provide evidence in support of a model, which shows that the relative multisubstrate specificity of ThMA is influenced by the monomer/dimer equilibrium of the enzyme.

Anti-inflammatory effect of adenovirus-mediated IkappaBalpha overexpression in respiratory epithelial cells

Many studies into basic biological characteristics of inflammation and tissue injury have implicated pro-inflammatory cytokine-mediated tissue injury in the pathogenesis of inflammatory lung diseases. Because transcription of most proinflammatory cytokines is dependent on the activation of nuclear factor (NF)-kappaB, NF-kappaB could be a good potential target to suppress the cytokine cascade. Cytokine-induced activation of NF-kappaB requires phosphorylation and subsequent degradation of IkappaBa. Therefore, the blocking NF-kappaB activation by IkappaBalpha could inhibit the pro-inflammatory cytokine-induced tissue injury. To evaluate whether blocking of NF-kappaB activation shows an anti-inflammatory effect, this study investigated the effect of adenovirus-mediated overexpression of IkappaBalpha super-repressor (IkappaBalpha-SR) on the pro-inflammatory cytokine expression in respiratory epithelial cells. The transduction efficiency of adenovirus was >90% in both A549 and NCI-H157 cells. Ad5IkappaBalpha-SR-transduced cells expressed high levels of IkappaBalpha-SR, which was resistant to tumour necrosis factor (TNF)-alpha-induced degradation. Adenovirus-mediated overexpression of IkappaBalpha-SR blocked cytokine-induced nuclear translocation of p65 and NF-kappaB deoxyribonucleic acid binding activity without affecting total cellular expression level of NF-kappaB. Ad5IkappaBalpha-SR transduction suppressed cytokine-induced interleukin-8 and TNF-alpha expressions at both ribonucleic acid and protein levels. These results suggest that blocking the nuclear factor-kappaB pathway by adenovirus-mediated overexpression of IkappaBalpha-super-repressor shows an effective anti-inflammatory effect in respiratory epithelial cells.

Arabidopsis dynamin-like 2 that binds specifically to phosphatidylinositol 4-phosphate assembles into a high-molecular weight complex in vivo and in vitro

Arabadopsis dynamin-like (ADL) 2, a member of the high-molecular weight (M(r)) dynamin family found in Arabidopsis, has been shown to be targeted to the plastid. In the chloroplast, most of the ADL2 was present in the fraction containing the envelope membranes when analyzed by suborganellar fractionation. Sucrose gradient and gel filtration experiments showed that when associated with membranes, ADL2 existed as a high-M(r) complex, whereas the soluble form existed as a monomer. The recombinant ADL2 expressed in Escherichia coli was present as a high-M(r) form and showed higher GTPase activity at a low NaCl concentration, whereas ADL2 existed as a low-M(r) form with a low level of GTPase activity at a high NaCl concentration. Electron microscopy studies revealed that the purified recombinant ADL2 formed spiral-coiled structures or rings. In the presence of guanosine-5'-O-(3-thio)triphosphate, these structures were transformed into a long rod structure. In contrast, in the presence of GDP, these structures disassembled into oligomers that were shown to be tetramer with 4-fold symmetry. Finally, a lipid-binding assay revealed that recombinant ADL2 purified from E. coli bound specifically to phosphatidylinositol 4-phosphate. Together, these results demonstrated that the biochemical properties of ADL2 were very similar to those of dynamin and other related proteins. Based on this similarity, we propose that ADL2 may be involved in vesicle formation at the chloroplast envelope membrane.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Phase II Trial of Vinorelbine and Cisplatin Chemotherapy in Advanced Non-Small Cell Lung Cancer

PURPOSE

Platinum-based chemotherapy has conferred a modest but significant survival benefit and the introduction of newer drugs has led to achieve higher response rate in patients with advanced non-small cell lung cancer (NSCLC). We performed a phase II trial in order to evaluate the efficacy and toxicity of combination chemotherapy with vinorelbine (Navelbine) and cisplatin in advanced NSCLC.

MATERIALS AND METHODS

Patients with previously untreated, unresectable stage IIIB or IV NSCLC with measurable lesion (s) were eligible for entry into the study. NP chemotherapy consisted of intravenous vinorelbine 25 mg/m2, on day 1 and 8, and intravenous cisplatin 80 mg/m2 on day 1; this cycle was repeated every three weeks.

RESULTS

A total of 33 patients were enrolled in the study between July 1999 and Feb 2000. Of the 30 patients deemed eligible for analysis, thirteen patients achieved a partial response and thirteen showed a stable disease. The overall response rate was 43.3%. The median duration of response was 5.7 months (95% CI: 2.8~8.5 months). The median time to progression was 7.6 months (95% CI: 5.5~9.7 months) and the overall median survival time was 15.1 months (95% CI: 9.8~20.4 months) in the intent-to-treat analysis. Chemotherapy-related grade 3 or 4 toxicities were anemia in 1.5%, leukopenia in 4.5%, nausea/vomiting in 2.3%, alopecia in 13.3%, and neurotoxicity in 3.3%.

CONCLUSION

The combination of vinorelbine and cisplatin chemotherapy seems to be active and fairly tolerable in patients with advanced NSCLC.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

Alterations of HLA class I and II antigen expression in preinvasive, invasive and metastatic cervical cancers

HLA expression is altered in a large variety of human cancers. We performed immunohistochemical staining on tissues from normal, preinvasive, invasive and metastatic cervical cancer tissues using anti-HLA class I or class II antibody. In tissues from normal squamous epithelium, carcinoma in situ (CIS) and microinvasive carcinoma (MIC), the expressions of HLA-B, C heavy chains and class II heavy chain were significantly decreased as disease progressed. When the expression patterns were compared between primary and metastatic squamous cell carcinoma (SCC) lesions, statistically significant down-regulation of HLA class I and class II antigen in metastatic lesions was observed. The rates of HLA-B, C heavy chains and class II heavy chain expressions were all significantly down-regulated compared to the down-regulation rate of class I beta2-microglobulin (beta2m) in invasive squamous lesions, and the expressions of class II heavy chain in metastatic lesions was decreased further than that in primary lesions. Unlike SCC, the degree of HLA class I and class II loss was not evident as disease progressed in early stage of adenocarcinoma. In invasive adenocarcinoma lesions, only the expression of HLA-B, C heavy chains was decreased and no differences were seen in HLA-B, C heavy chain expression patterns between primary and metastatic lesions. These results suggest that alterations of HLA class I and II expressions seem to occur at a particular step in cervical cancer development and depend on tissue types: when the tumor becomes invasive and starts to metastasize.

Protein kinase C modulates telomerase activity in human cervical cancer cells

Telomerase, a ribonucleoprotein reverse transcriptase that extends telomeres of eukaryotic chromosomes is repressed in normal somatic cells but is activated during development and neoplasia. The regulation mechanism of telomerase activity in cancer cells is not clearly known. In this report, a possible affect of PKC on telomerase activity was examined using HeLa and CUMC-6 cervical cancer cell lines. Exposure of cells to PKC inhibitor, bisindolylmaleimide I and Gö6976, and high levels of PKC activator, 12-O-tetradecanoyl phorbol 13-acetate (TPA) resulted in the inhibition of PKC activity in both cells. Telomerase activities were also inhibited by bisindolyl-maleimide I and Gö6976, respectively, in a time-dependent manner. As PKC activity changes in TPA-treated cervical cancer cells, telomerase activities were increased at low dose of TPA and decreased at high dose. The expression levels of human telomerase subunits, human telomerase RNA (hTR) were not influenced by PKC modulating drugs. In contrast, the expression of full-length human telomerase reverse transcriptase (hTERT) was decreased after exposure to bisindolylmaleimide I and Gö6976 in a time-dependent manner. hTERT expression was not affected by low dose of TPA. In contrast, high dose of TPA inhibited hTERT expression level. But the expression patterns of beta-deletion transcript of hTERT after 72 h of treatment with PKC inhibitors or high dose of TPA exposure were not discernable as compared with those of full-length hTERT transcripts to PKC modulating drugs. These results suggest that PKC-modulating drugs altered telomerase activities by affecting full-length hTERT expression profile in human cervical cancers.

Expression of the c-erb-B2 and p53 protein in gallbladder carcinomas

Gallbladder carcinoma is the most common malignancy of the biliary tract in Korea and known to be more common in East Asia and Latin America than in Europe and North America. However, their exact histopathological characteristics and carcinogenesis are not well-elucidated. A total of 71 cases of gallbladder carcinomas, two cases of gallbladder dysplasia and 20 cases of gallbladder adenoma were immunohistochemically studied to evaluate the expression of c-erb-B2 and p53 proteins in the light of their relationship with various prognostic factors. Thirty-three gallbladder carcinomas (46.5%) showed positive staining for c-erb-B2, but none of the dysplasia and adenoma were positive (p<0.05). c-erb-B2 was stained in the cell membrane of the cancer cells. Adjacent normal mucosa was negative for c-erb-B2 staining. Forty-eight gallbladder carcinomas (67.6%) showed positive staining in the nucleus for p53 protein. None of the cases with dysplasia, adenoma, and normal mucosa stained positive for p53 protein. There was no significant correlation between c-erb-B2 and p53 expression and age, gender, histological tumor grade, and tumor stage. In the multivariate analysis, tumor stage approached statistical significance (p=0.05), but c-erb-B2 and p53 expression was not significant (p=0.14 and p=0.29, respectively). The mean survival periods of the c-erb-B2 positive and negative groups were 26 months and 52 months, respectively (p=0.02). However, the mean survival periods of the p53 protein positive and negative patients were 34 months and 35 months, respectively (p=0.45). In conclusion, our results suggest that c-erb-B2 and p53 protein expression is strongly associated with neoplastic progression in gallbladder carcinomas, and that c-erb-B2 expression identifies patients with a worse prognosis.

An adenovirus expressing mutant p27 showed more potent antitumor effects than adenovirus-p27 wild type

The main inhibitory action of p27, a cyclin-dependent kinase inhibitor (CDKI), arises from its binding with the cyclin E/cyclin-dependent kinase 2 (Cdk2) complex that results in G(1)-S arrest. Degradation of p27 is mediated by phosphorylation of Thr-187 of p27, which follows ubiquitination. In this study, we generated two adenoviruses expressing wild-type p27 (ad-p27wt) and mutant p27 (ad-p27mt), with mutation of Thr-187/Pro-188 (ACGCCC) to Met-187/Ile-188 (ATGATC), which was produced with the belief that mutant p27 would bind cyclin E/CDK2 more stably and show more potent antitumor effects. Ad-p27wt and ad-p27mt expressed p27 proteins that were indistinguishable by anti-p27 antibody. A pulse chase experiment showed that p27mt was more resistant to degradation than p27wt. In human lung cancer cell lines, ad-p27mt showed stronger growth inhibition than ad-p27wt. Both types of ad-p27 induced G(1)-S arrest and apoptosis; however, ad-p27mt induced stronger G(1)-S arrest and apoptosis. Intratumoral injection of ad-p27mt induced partial regression of established tumors and inhibited the growth of human lung cancer xenografts more strongly than ad-p27wt. From these results, we conclude that ad-p27mt has the potential to become a novel and powerful gene therapy tool.

Characterization of a novel laccase produced by the wood-rotting fungus Phellinus ribis

The white-rot fungus Phellinus ribis produced a single form of laccase, which was purified to apparent electrophoretic homogeneity from cultures induced with 2,5-xylidine. This protein was a dimer, consisting of two subunits of 76 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Carbohydrate analysis revealed that the enzyme contained about 28% carbohydrate content. The laccase appeared to be different from other known laccases by the UV-visible absorption spectrum analysis. One enzyme molecule contained one copper, one manganese, and two zinc atoms. The laccase showed optimal activity at pH 4.0-6.0, 5.0, and 6.0 with 2,6-dimethoxyphenol, ABTS [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)], and syringaldazine, respectively. The enzyme preferably oxidized dimethoxyphenol and aromatic amine compounds. The stability of the laccase was low at acidic pH, whereas it showed high stability at neutral pH and mild temperature. The N-terminal amino acid sequence revealed a very low homology with other microbial laccases. With some substrates, the addition of manganese and H2O2 resulted in a remarkable increase in the oxidation rate. Without an appropriate phenolic substrate, the enzyme could not oxidize Mn(II) in the presence of H2O2 or pyrophosphate.

Effect of high fat diet on insulin resistance: dietary fat versus visceral fat mass

The purpose of the present study was to determine whether chronic high-fat diet (HF) induces insulin resistance independently of obesity. We randomly divided 40 rats into two groups and fed them either with a HF or with a high-carbohydrate diet (HC) for 8 weeks. Whole body glucose disappearance rate (Rd) was measured using a euglycemic hyperinsulinemic clamp. Firstly, we defined whether insulin resistance by HF was associated with obesity. Plasma glucose and triglyceride concentrations were significantly increased in HF. Rd was decreased (10.6+/-0.2 vs. 9.1+/-0.2 mg/kg/min in HC and HF, respectively) and the hepatic glucose output rate (HGO) was increased in HF (2.2+/-0.3 vs. 4.5+/-0.2 mg/kg/min in HC and HF, respectively). Rd was significantly correlated with %VF (p<0.01). These results implicate that visceral obesity is associated with insulin resistance induced by HF. In addition, to define whether dietary fat induces insulin resistance regardless of visceral obesity, we compared Rd and HGO between groups 1) after matching %VF in both groups and 2) using an ANCOVA to adjust for %VF. After matching %VF, Rd in HF was significantly decreased by 14% (p<0.001) and HGO was significantly increased by 110% (p<0.001). Furthermore, statistical analyses using an ANCOVA also showed Rd for HF was significantly decreased even after adjusting %VF. In conclusion, we suggest that dietary fat per se could induce insulin resistance in rats fed with chronic HF independently of obesity.

Pharmacokinetic studies of 2-amino-9-(3-acetoxymethyl-4-isopropoxycarbonyl-oxybut-1-yl)purine, an oral prodrug for the antiviral agent penciclovir

2-Amino-9-(3-acetoxymethyl-4-isopropoxycarbonyloxybut-1-yl)- purine (SK1899) was tested as an oral prodrug for penciclovir. SK1899 was administered orally to rats and dogs at doses up to 2 and 0.68 mmol/kg, respectively. SK1899 was well absorbed, and the major metabolites detected in plasma and urine were penciclovir, the active antiviral compound, and 6-deoxypenciclovir (M4) in both species. In rats, SK1899 was rapidly and extensively metabolized to penciclovir, which reached the peak plasma concentration (C(max)) of 39.5 microM at 0.5 h after 0.2-mmol/kg dosing. The area under the plasma concentration-time curve (AUC) for penciclovir was 57.5 microM x h. After an oral dose of 0.034 mmol/kg to dogs, extensive conversion of SK1899 to penciclovir also occurred with slower rate of formation of penciclovir from M4 than in rats. The mean C(max) and AUC for penciclovir were 4.5 microM at 2.7 h and 28.2 microM x h, respectively. The 0- to 24-h urinary recovery of penciclovir represented 36.1 and 36.3% of dose to rats and dogs, respectively. Radioactivity was found in fetuses following an oral administration of [(14)C]SK1899 to pregnant rats, but no significant accumulation was observed. Although substantial milk transfer of [(14)C]SK1899 occurred in rats, the radioactivity in milk was rapidly cleared. The values of C(max), AUC, and urinary recovery of penciclovir after dosing with SK1899 to rats and dogs were similar or slightly higher than those from famciclovir. These data indicate that introduction of an isopropoxy carbonate group into one of the two hydroxyl groups of M4 did not significantly alter the oral bioavailability of penciclovir compared with famciclovir.

Synthesis and phosphodiesterase 5 inhibitory activity of novel phenyl ring modified sildenafil analogues

New sildenafil analogues containing an ether ring fused into the phenyl moiety, 6a--d and 7a--d, were efficiently synthesized from the readily available starting materials, 1a--d and 2, in five steps. Ab initio calculations indicated that introduction of a cyclic ether to the phenyl group might enhance the co-planarity of the molecule. The torsional angles were calculated to be 2--3 degrees for the 5-membered cyclic ether derivatives, 6a, 6c, 7a, and 7c, and 12--16 degrees for the 6-membered ones, 6b, 6d, 7b, and 7d. On the other hand, sildenafil showed the least co-planarity with the torsional angle of 23 degrees compared with the target compounds, 6a--d and 7a--d. In the enzyme assay, however, the in vitro PDE 5 inhibitory activity was found out to be inversely related to the degree of co-planarity. In other words, the least planar sildenafil showed the highest activity, and the most planar 5-membered cyclic ether derivatives were least active by 100--200-fold compared with sildenafil. Our study clearly demonstrated that the open chain 2'-alkoxy group of the phenyl ring, although less effective for inducing the co-planarity, seemed to act as a much better lipophilic requirement than the cyclic alkoxy moiety.

A human case of gastric infection by Pseudoterranova decipiens larva

We report a case of gastric pseudoterranoviasis proven by gastrofiberscopy on Dec. 13, 1994. The 34-year-old male patient, residing in Chungju-shi, was admitted to Konkuk University Hospital complaining of prickling epigastric pain. The symptoms suddenly attacked him two days after eating raw marine fish at Chonan-shi. By the gastrofiberscopic examination, a long white-yellowish nematode was found from the fundus region of stomach. The worm was 34.50 x 0.84 mm in size, and was identified as a 3rd stage larva of Pseudoterranova decipiens judging from the position of the intestinal cecum. This is the 12th confirmed case of human pseudoterranoviasis in Korea.

Synthesis and biological evaluation of novel A-ring modified hexacyclic camptothecin analogues

Eleven A-ring modified hexacyclic analogues of camptothecin (CPT) containing a 1,4-oxazine ring were synthesized from 10-hydroxycamptothecin (11a) and 7-ethyl-10-hydroxycamptothecin (3) (SN-38) in four to five steps and were subjected to the biological tests such as cytotoxicity, topoisomerase I (Topo I) inhibitory activity, acetylcholinesterase (AChE) inhibition, and stability in human plasma. Four compounds 15a, 15b, 16a, and 16c were about 2-fold more potent than topotecan and as potent as CPT toward human cancer cell lines A549, H128, WiDr, MKN45, SK-OV-3, and SK-BR-3 in vitro, even though the most active compound 15b was slightly less potent than SN-38. The potency of Topo I inhibition of these compounds showed relatively good correlation with their cytotoxicity. Most of the compounds exhibited AChE inhibitory activity weaker (9 +/- 2 to 20 +/- 3%) than CPT (23 +/- 5%) or topotecan (20 +/- 4%) and similar to SN-38 (13 +/- 2%), indicating that they might have little effect on causing early diarrhea. The stability of lactone forms of these compounds in human plasma seemed to be much higher than that of CPT and similar to that of topotecan but lower than that of SN-38. Among the new hexacyclic CPT analogues, compound 15b showed higher antitumor activity against human tumor xenograft, WiDr, in nude mice compared to that of SN-38. The most promising compound 15b has been selected for further development.

Increased expression of cFLIP(L) in colonic adenocarcinoma

During tumour progression, cancer cells use diverse mechanisms to escape from apoptosis-inducing stimuli, which may include receptor internalization, inhibition of signal pathways, and regulation of specific sets of genes. Substantial numbers of colon cancer cells have been observed to express Fas/Fas ligand, but are resistant to Fas-mediated apoptosis, suggesting that colonic tumours might develop specific mechanisms to overcome Fas-mediated apoptosis. Recently, cellular FLICE-like inhibitory protein (cFLIP) has been identified as an endogenous inhibitor of Fas- or other receptor-mediated apoptosis and its altered high expression has a suspected association with tumour development or progression. In an effort to investigate the prevalence of cFLIP(L) alterations in colon carcinomas and their possible implications for the progression of colon cancers, cFLIP(L) expression was analysed in adenocarcinomas and adenomatous polyps of colon, with matched normal tissues, at RNA and protein levels, by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. cFLIP(L) transcripts were constitutively expressed in colon cancers and expression levels were significantly higher in carcinomas than in normal tissues (p<0.05). Overexpression of cFLIP(L) protein was found exclusively in carcinoma cells in all matched sets analysed and approximately three-fold induction was detected in cancer cells (p<0.05). The expression of cFLIP(L) protein was not significantly altered in adenomatous polyps compared with normal tissues. Taken together, these results strongly suggest that abnormal overexpression of cFLIP(L) is a frequent event in colon carcinomas and might contribute to in vivo tumour transformation.

P53 mutations in Ewing's sarcoma

The p53 tumor suppressor gene is one of the most frequently altered genes in human malignancies. To explore the implication of p53 alteration in Ewing's sarcoma, we analyzed the deletion and sequence alterations of p53 and abnormal amplification of MDM2, which acts as a functional inhibitor of p53, in 35 tissue specimens. Quantitative genomic PCR analysis showed that 2 of 35 tumors have extremely low levels of the p53 gene, indicating a homozygous deletion of the gene. Mutational analysis of exons 4 to 9 of p53 by PCR-SSCP revealed that 3 of 35 tumors carry sequence alterations in exons 5 or 8, and DNA sequencing analysis identified missense point mutations at codon 132 (AAG-->ATG, lysine-->methionine) and codon 135 (TGC-->TCC, cystein-->serine) in exon 5, and codon 287 (GAG-->GTG, glutamic acid-->valine) in exon 8 from these tumors. No abnormal amplification of the MDM2 gene was recognized. Taken together, our data demonstrate that p53 is genetically altered in a small fraction of Ewing's sarcoma.

Membrane curvature induced by polymer adsorption

The phenomena resulting from interaction between polymers and membranes pose important problems for biological applications. Based on a scaling theory, we investigate the spontaneous curvature of a membrane induced by either flexible or semiflexible chain adsorption. Irrespective of chain stiffness, a weakly adsorbed polymer induces the membrane to bend away (to have a positive curvature) from the polymer mostly due to increase of the conformational entropy compared with that for a flat surface. On the other hand, a strongly adsorbed polymer induces the membrane to bend toward the polymer mostly due to decrease in the interaction energy, leading to a possibility of encapsulation of polymer by the membrane.

A functional myo-inositol dehydrogenase gene is required for efficient nitrogen fixation and competitiveness of Sinorhizobium fredii USDA191 to nodulate soybean (Glycine max [L.] Merr.)

Inositol derivative compounds provide a nutrient source for soil bacteria that possess the ability to degrade such compounds. Rhizobium strains that are capable of utilizing certain inositol derivatives are better colonizers of their host plants. We have cloned and determined the nucleotide sequence of the myo-inositol dehydrogenase gene (idhA) of Sinorhizobium fredii USDA191, the first enzyme responsible for inositol catabolism. The deduced IdhA protein has a molecular mass of 34,648 Da and shows significant sequence similarity with protein sequences of Sinorhizobium meliloti IdhA and MocA; Bacillus subtilis IolG, YrbE, and YucG; and Streptomyces griseus StrI. S. fredii USDA191 idhA mutants revealed no detectable myo-inositol dehydrogenase activity and failed to grow on myo-inositol as a sole carbon source. Northern blot analysis and idhA-lacZ fusion expression studies indicate that idhA is inducible by myo-inositol. S. fredii USDA191 idhA mutant was drastically affected in its ability to reduce nitrogen and revealed deteriorating bacteroids inside the nodules. The number of bacteria recovered from such nodules was about threefold lower than the number of bacteria isolated from nodules initiated by S. fredii USDA191. In addition, the idhA mutant was also severely affected in its ability to compete with the wild-type strain in nodulating soybean. Under competitive conditions, nodules induced on soybean roots were predominantly occupied by the parent strain, even when the idhA mutant was applied at a 10-fold numerical advantage. Thus, we conclude that a functional idhA gene is required for efficient nitrogen fixation and for competitive nodulation of soybeans by S. fredii USDA191.

Alteration of cell growth and morphology by overexpression of transforming growth factor beta type II receptor in human lung adenocarcinoma cells

TGF-beta is a potent inhibitory regulator of cell growth, which is transduced through interaction between type I (RI) and type II (RII) receptors that form heteromeric kinase complexes. Abnormal expression of these receptors has been identified in several human epithelial cancers and has been shown to be highly associated with resistance to TGF-beta. In this study, we investigated the expression of RI and RII in 13 human non-small cell lung cancer cell lines (NSCLCs) and demonstrated decreased or loss of RII expression in five lung cancer cell lines, but not of RI. Of these cell lines, the role of RII in NCI-H358 adenocarcinoma, which lacks RII and is insensitive to TGF-beta, was investigated by transducing this cell line with a recombinant retrovirus expressing full-length TGF-beta RII. Stably transfected cells showed significant increase in RII mRNA and protein expression. These cells responded to exogenous TGF-beta1 with suppressed proliferation in a dose-dependent manner and G1 arrest accompanied by morphological change distinct from control cells. We also investigated whether overexpression of dominant-negative RII (dnRII) in NCI-H441 adenocarcinoma, which is sensitive but expresses low levels of RII, could block signaling through the receptor complex. The overexpression of this kinase-domain-truncated RII by expressing the retroviral dnRII construct led to loss of the ability to respond to TGF-beta1 and an exhibition of uncontrolled growth. These results suggest a close association between the loss of the expression of wild-type TGF-beta RII and carcinogenesis in human lung cancer cells.