Fibroblast-mediated acceleration of human epithelial tumor growth in vivo

Transformed fibroblasts coinoculated with epithelial cells accelerated the growth and shortened the latency period of human epithelial tumors in athymic mice. Addition of NbF-1 fibroblasts caused epithelial tumors to grow from five marginally tumorigenic or "nontumorigenic" (nontumor-forming) human tumor cell lines or strains: PC-3 (prostate), WH (bladder), MDA-436 (breast), and cells derived from the ascites fluids of patients with metastatic renal pelvic or prostate cancers. Evidence for the human and epithelial nature of these experimental tumors was provided by histologic, immunohistochemical, Southern and dot-blot hybridization, and cytogenetic analyses. Transformed fibroblasts induced predominantly carcinosarcomas, whereas nontumorigenic fibroblasts (NIH 3T3) and lethally irradiated transformed fibroblasts induced exclusively carcinomas. The fibroblast-epithelial interaction appears to occur bidirectionally and does not result from cell fusion. Because coculture experiments in vitro did not demonstrate an increased cell proliferation, it appears that undefined host factors can influence tumor growth. This tumor model may be useful in drug-screening programs and in mechanistic studies of factors regulating human tumor growth and progression.

International consensus on (ICON) pediatric asthma

Asthma is the most common chronic lower respiratory disease in childhood throughout the world. Several guidelines and/or consensus documents are available to support medical decisions on pediatric asthma. Although there is no doubt that the use of common systematic approaches for management can considerably improve outcomes, dissemination and implementation of these are still major challenges. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), recently formed by the EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus on (ICON) Pediatric Asthma. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences, thus providing a concise reference. The principles of pediatric asthma management are generally accepted. Overall, the treatment goal is disease control. To achieve this, patients and their parents should be educated to optimally manage the disease, in collaboration with healthcare professionals. Identification and avoidance of triggers is also of significant importance. Assessment and monitoring should be performed regularly to re-evaluate and fine-tune treatment. Pharmacotherapy is the cornerstone of treatment. The optimal use of medication can, in most cases, help patients control symptoms and reduce the risk for future morbidity. The management of exacerbations is a major consideration, independent of chronic treatment. There is a trend toward considering phenotype-specific treatment choices; however, this goal has not yet been achieved.

Molecular evidence of natural hybridization between Fasciola hepatica and F. gigantica

Nucleotide sequences of two regions, cytochrome c-oxidase subunit 1 (CO1) and NADH dehydrogenase subunit 1 (ND1) of the mitochondrial DNA and two regions, internal-transcribed spacer 2 (ITS2) and the D2 region in the 28S rDNA (28S) of the nuclear DNA were obtained from five Korean worms of the genus Fasciola in order to elucidate their taxonomic status. The CO1 and ND1 regions are all monomorphic in the Korean worms and similar to those of F. gigantica. On the other hand, the ITS2 and D2 regions were found to be polymorphic; that is, out of five worms, two possessed a F. gigantica-type sequence, one, a F. hepatica-type sequence and two possessed sequences of both types indicating an existence of different alleles at the loci. It should be noted that these variations of the ITS2 and D2 regions co-occur at the same individual worms. This was confirmed by sequencing five to six cloned PCR products for each worm. The present study strongly suggests interspecific cross-hybridization between the two species coexisting in Korea.

Multiple predictors of coronary restenosis after drug-eluting stent implantation in patients with diabetes

OBJECTIVES

To identify parameters influencing the likelihood of restenosis after implantation of drug-eluting stents (DES) in patients with diabetes.

METHODS

Stented patients (n = 840) with DES were retrospectively reviewed for inclusion in the study from the Multicenter PCI Database Registry. From this database, 211 (25.1%) of 840 patients with six-month angiographic follow up had diabetes. Predictors of coronary restenosis were identified with univariate and multivariate logistic regression analyses.

RESULTS

Restenosis occurred in 92 of 629 (14.6%) patients without diabetes and in 44 (20.9%) of 211 patients with diabetes (p < 0.001). Multivariate parameters for predicting restenosis in the diabetic group were current smoking (odds ratio (OR) 1.923, 95% confidence interval (CI) 1.055 to 4.725, p = 0.036), higher C reactive protein concentration (OR 1.031, 95% CI 1.011 to 1.075, p = 0.043), use of the paclitaxel-eluting stent (OR 2.638, 95% CI 1.338 to 5.200, p = 0.005), longer stent length (OR 1.065, 95% CI 1.021 to 1.119, p = 0.033), smaller reference diameter before DES implantation (OR 0.501, 95% CI 0.110 to 0.965, p = 0.040), smaller reference diameter (OR 0.455, 95% CI 0.120 to 0.814, p = 0.026) and minimum lumen diameter (OR 0.447, 95% CI 0.068 to 0.876, p = 0.039) after DES implantation.

CONCLUSION

Even with the introduction of DES, diabetes remains a significant predictor of coronary restenosis, especially in cases of a small baseline vessel size, small vessel size after percutaneous coronary intervention, longer stent length, use of the paclitaxel-eluting stent, current smoking and high C reactive protein concentration.

Management of malignant stricture of the esophagogastric junction with a newly designed self-expanding metal stent with an antireflux mechanism

BACKGROUND AND STUDY AIMS

When stents are placed across the esophagogastric junction for palliative treatment of malignant strictures, they may lead to esophagogastric reflux. The aim of this study was to compare the effectiveness of a newly designed antireflux stent with that of a standard open stent and a currently available antireflux stent (Dostent) in preventing gastroesophageal reflux symptoms in patients with inoperable cancer at the esophagogastric junction.

PATIENTS AND METHODS

Thirty-six consecutive patients with cancer at the esophagogastric junction were randomly assigned to undergo placement of a newly designed antireflux stent (n = 12), a Dostent (n = 12), or a standard open stent (n = 12). Technical and clinical success, dysphagia score, reflux symptoms, complications and ambulatory 24-h esophageal pH monitoring were assessed.

RESULTS

The technical success rates were 100 %. After 1 week, dysphagia had improved in all patient groups ( P < 0.05), but the degree of improvement did not differ between the three groups. The DeMeester score was significantly lower in the group with the newly designed antireflux stent than in the other groups. The fraction of the total recording time during which esophageal pH was below 4 was 3.14 +/- 5.78 % using the newly designed antireflux stent, in comparison with 29.25 +/- 15.41 % in the Dostent group and 15.01 +/- 11.72 % in the standard open stent group ( P < 0.001). Fewer reflux episodes occurred with the newly designed antireflux stent than with the Dostent or standard open stent. There were no complications with any of the three stents.

CONCLUSIONS

The newly designed antireflux stent is effective in relieving dysphagia caused by malignant cancer at the esophagogastric junction. The newly designed antireflux stent is significantly more effective in preventing gastroesophageal reflux than currently available antireflux stents.

Comparison of fatty acid profiles in the serum of patients with prostate cancer and benign prostatic hyperplasia

OBJECTIVE

The role of dietary fatty acids (FAs) in benign and malignant prostatic diseases was investigated by comparing the composition value of serum fatty acids in the normal controls, and patients with prostate cancer (PC) and benign prostatic hyperplasia (BPH). Also, to estimate a possible association between PC risk and PUFAs, omega-3, omega-6 and omega-3/omega-6 FA composition ratios were compared among these groups.

METHODS

Serum samples were obtained from 24 BPH and 19 PC patients, and from 21 age-matched normal male subjects. The serum concentration of 21 fatty acids was determined using gas chromatography/mass spectrometry.

RESULT

The proportional values of saturated fatty acids (SFAs) groups demonstrated no specific difference between the control subjects and the patients. In the polyunsaturated fatty acids (PUFAs), we found that the omega-3 PUFAs level was significantly decreased in patient with BPH and PC and that the omega-6 PUFAs level was increased in PC only. The ratio of omega-3/omega-6 PUFAs decreased in the following order of normal, BPH, and PC.

CONCLUSION

It was proposed that the changed composition level of PUFAs including omega-3 and omega-6 PUFAs have certain relationship with both prostatic diseases. Therefore, the ratio of omega-3/omega-6 PUFAs also may have an important association with the benign and malignant status of prostatic disease.

Use of geographutoxin II (mu-conotoxin) for the study of neuromuscular transmission in mouse

1. Endplate potentials (e.p.ps) were investigated in the presence of geographutoxin II (GTXII) in the mouse phrenic nerve diaphragm preparation. This toxin preferentially blocks muscle Na+ channels which allows the study of e.p.ps in the absence of nicotinic receptor antagonists or substances to depress acetylcholine release. 2. GTXII abolished muscle action potentials and antagonized the depolarization of the muscle membrane produced by the crotamine-induced opening of Na+ channels. 3. E.p.ps as large as 19-25 mV were observed after 2-4 micrograms ml-1 GTXII. These concentrations of GTXII did not cause discernible changes of resting membrane potential and frequency and amplitude of miniature e.p.ps. 4. Lower concentrations (1-2 micrograms ml-1) of GTXII caused incomplete blockade of the muscle Na+ channel resulting in exaggerated 'e.p.ps', while higher concentrations of GTXII (8 micrograms ml-1) abolished e.p.ps by a prejunctional effect. 5. Trains of e.p.ps on repetitive stimulation after GTXII neither ran down, as in tubocurarine-treated preparations, nor facilitated, as in low Ca2+ and/or high Mg2+-treated preparations, and were indistinguishable from those of untreated cut muscle preparation. 6. In cut muscle preparations, GTXII did not affect the rise and decay times, amplitude or rundown of e.p.ps. 7. It is concluded that GTXII is a useful agent for studying neuromuscular transmission. This method provides e.p.ps which are neither attenuated nor modified because manipulations that alter transmitter release and postjunctional receptor responses are avoided.

Inhibition of VEGF blocks TGF-beta1 production through a PI3K/Akt signalling pathway

Vascular endothelial growth factor (VEGF) is a mediator of airway inflammation and remodelling in asthma. Transforming growth factor (TGF)-beta(1) plays pivotal roles in diverse biological processes, including tissue remodelling and repair in a number of chronic lung diseases. However, there are few studies elucidating the interactions between VEGF and TGF-beta(1) in allergic airway disease. A murine model of allergic airway disease was used to define the mechanism by which VEGF induces subepithelial fibrosis and to investigate a potential relationship between VEGF and TGF-beta(1) and the mechanisms by which VEGF signalling regulates TGF-beta(1) expression in allergic airway disease. The ovalbumin (OVA)-inhaled murine model revealed the following typical pathophysiological features of allergic airway disease in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased peribronchial fibrosis, and increased levels of VEGF and TGF-beta(1). Administration of VEGF inhibitors reduced the pathophysiological signs of allergic airway disease and decreased the increased TGF-beta(1) levels and peribronchial fibrosis, including phosphoinositide 3-kinase (PI3K) activity after OVA inhalation. In addition, the increased TGF-beta(1) levels and collagen deposition after OVA inhalation were decreased by administration of PI3K inhibitors. These results suggest that inhibition of vascular endothelial growth factor attenuates peribronchial fibrosis, at least when mediated by regulation of transforming growth factor-beta(1) expression through phosphoinositide 3-kinase/Akt pathway in a murine model of allergic airway disease.

Molecular cloning and immunological characterization of phosphoglycerate kinase from Clonorchis sinensis

The parasite Clonorchis sinensis was determined to utilize a large amount of external glucose to carry its energy metabolism. Phosphoglycerate kinase (PGK), a glycolytic enzyme, found in many parasites, has been identified as one of the candidate molecules distinguished from human counterparts for vaccine and drug developments. A cDNA clone purified by screening a C. sinensis cDNA library using a heterologous cDNA probe encoded a putative peptide of 415 amino acids with over 60% identities with PGKs from a number of animals. The putative peptides revealed domains corresponding to 12 beta-sheets and inner loops forming a substrate-binding cleft of animal PGKs. The gene product was overexpressed in Escherichia coli and showed a PGK-like enzyme activity. A polyclonal antibody raised against the recombinant C. sinensis PGK was specific to native C. sinensis PGK and localized it to the muscular tissue and tegument of the adult flukes. The C. sinensis PGK elicited antibodies in C. sinensis-infected rabbits. Therefore, it is proposed that C. sinensis PGK could be used as an immunoreagent in the serodiagnosis for clonorchiasis.

Regulation of the tyrosine hydroxylase and dopamine beta-hydroxylase genes by the transcription factor AP-2

The retinoic acid-inducible and developmentally regulated transcription factor AP-2 plays an important role during development. In adult mammals, AP-2 is expressed in both neural and non-neural tissues. However, the function of AP-2 in different neuronal phenotypes is poorly understood. In this study, transcriptional regulation of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH) genes by AP-2 was investigated. AP-2 binding sites were identified in the upstream regions of both genes. Electrophoretic mobility shift assays (EMSA) and DNase I footprinting analyses indicate that the AP-2 interaction with these motifs is more prominent in catecholaminergic SK-N-BE(2)C and CATH.a than in non-catecholaminergic HeLa and HepG2 cell lines. Exogenous expression of AP-2 robustly transactivated TH and DBH promoter activities in non-catecholaminergic cell lines. While AP-2 regulates the DBH promoter activity via a single site, transactivation of the TH promoter by AP-2 appears to require multiple sites. In support of this, mutation of multiple AP-2 binding sites but not that of single site diminished the basal promoter activity of the TH gene in cell lines that express TH and abolished transactivation by exogenous AP-2 expression in cell lines that do not express TH. In contrast, mutation of a single AP-2 binding site of the DBH gene completely abolished transactivation by AP-2. Double-label immunohistochemistry showed that AP-2 is coexpressed with TH in noradrenergic and adrenergic neurons in both the central and peripheral nervous systems of adult rodents. Numerous non-catecholaminergic cell groups within the spinal cord, medulla, cerebellum, and pons also express AP-2. The concentration of AP-2 in dorsomedial locations along the neuraxis suggests a regionally specific role for this transcription factor in the regulation of neuronal function. Based on these findings we propose that AP-2 may coregulate TH and DBH gene expression and thus participate in expression/maintenance of neurotransmitter phenotypes in (nor)adrenergic neurons and neuroendocrine cells.

Inhibition of acetylcholine release from mouse motor nerve by a P-type calcium channel blocker, omega-agatoxin IVA

1. The effects were studied of the central neurone P-type Ca2+ channel blockers, omega-agatoxin IVA, omega-conotoxin MVIIC (polypeptide toxins) and synthetic funnel-web spider polyamine toxin on acetylcholine release from mouse motor nerve. 2. omega-Agatoxin IVA decreased the quantal content of endplate potentials and blocked synaptic transmission in the nanomolar range in a reversible manner, whereas the other toxins depressed transmission in the hundred micromolar range. 3. The polyamine toxin, but not the polypeptide toxins, decreased the amplitude of the miniature endplate potential. The increase in the frequency of miniature endplate potentials evoked by high [K+], but not that evoked by alpha-latrotoxin, was effectively antagonized by omega-agatoxin IVA. 4. In the presence of omega-agatoxin IVA, high frequency nerve stimulation produced facilitation of endplate currents and tetanic contractions. 5. The results suggest that, under physiological conditions, the Ca2+ necessary for nerve action potential-evoked acetylcholine release is translocated via a subtype of the P-type Ca2+ channel sensitive to omega-agatoxin IVA.

Risk factors for recurrence in patients with papillary thyroid carcinoma undergoing modified radical neck dissection

BACKGROUND

This study evaluated the impact of lymph node-related factors on the risk of and site of recurrence in patients who had papillary thyroid carcinoma with lymph node metastasis in the lateral compartment (classified as pN1b).

METHODS

Patients underwent total thyroidectomy with unilateral modified radical neck dissection for classical papillary thyroid carcinoma. Risk factors for recurrence were evaluated according to the pattern of recurrence.

RESULTS

A total of 324 patients were included in the study. The median follow-up was 63 (range 14-181) months. Recurrence was detected in 47 patients (14·5 per cent). In the multivariable analysis, a maximum diameter of metastatic lymph nodes larger than 2·0 cm (hazard ratio (HR) 1·15, 95 per cent c.i. 1·06 to 1·25; P = 0·033) and a central compartment metastatic lymph node ratio of more than 0·42 (HR 3·35, 1·65 to 6·79; P < 0·001) were identified as independent risk factors for locoregional recurrence. Age 45 years or older (HR 5·69, 1·24 to 26·12; P = 0·025) and extranodal extension of metastasis (HR 12·71, 1·64 to 98·25; P = 0·015) were risk factors for distant metastasis. In subgroup analysis of locoregional recurrence, several lymph node-related factors affected the risk of recurrence according to the specific site of metastasis.

CONCLUSION

Lymph node-related factors are of importance for the risk of recurrence in patients with classical papillary thyroid carcinoma classified as pN1b.

Pepsin-digested peanut contains T-cell epitopes but no IgE epitopes

BACKGROUND

Peanuts are a common cause of food-induced anaphylaxis and fatalities. Previous studies have demonstrated that rush immunotherapy to crude peanut extract reduces clinical symptoms triggered by oral peanut challenges, but the immunotherapy was associated with an unacceptably high incidence of systemic allergic reactions. One approach to reduce the frequency of allergic reactions would be to use a modified peanut antigen with low allergenic properties.

OBJECTIVE

We sought to determine the immunologic characteristics of crude intact peanut extract before and after pepsin digestion.

METHODS

We used IgE immunoblotting and assessment of T-lymphocyte responses to intact and peptic digests of peanut extracts.

RESULTS

Western blot analysis of sera from 5 subjects with peanut allergy showed multiple IgE-reactive proteins in crude intact peanut extract that were eliminated after pepsin treatment of the peanut extract. In contrast, pepsin-digested peanut induced significant T-cell proliferation responses (stimulation index = 30) in vitro in PBMCs from 7 subjects with peanut allergy, albeit at lower levels than that induced by intact peanut (stimulation index = 66). Furthermore, IFN-gamma production was induced by intact peanut and pepsin-digested peanut in a concentration-dependent manner. Importantly, T-cell lines generated in response to intact peanut also reacted to pepsin-digested peanut, indicating cross-reactive T-cell epitopes in intact and pepsin-digested peanut.

CONCLUSION

These findings suggest that pepsin-digested peanut may be useful in peanut immunotherapy because pepsin digestion eliminates IgE reactivity but maintains T-cell reactivity.

Prevalences of Gs alpha, ras, p53 mutations and ret/PTC rearrangement in differentiated thyroid tumours in a Korean population

OBJECTIVE

In thyroid tumours, ras, Gs alpha, p53 mutations and ret/PTC rearrangement have been reported with variable prevalences in different geographical regions. We studied the prevalence of these mutations and rearrangement in thyroid tumours in a Korean population. As MDM2 and Bcl-1 protein expressions have been suggested to be associated with p53 protein, we also studied possible relationships among them.

PATIENTS AND DESIGN

Eleven cases of adenomatous goitre, eight cases of follicular adenoma, five cases of follicular carcinoma and 37 cases of papillary carcinoma were included in this study. To find mutations and rearrangement, RT-PCR, SSCP and/or direct sequencing, after subcloning if necessary, were used, and immunohistochemical stainings were performed for p53, MDM2 and Bcl-2 proteins in cases of papillary carcinoma.

RESULTS

We could not find any rearrangement for ret/PTC-1, -2, -3 and mutation of Gs alpha. For the ras oncogene, K and H-ras mutations were not found, but N-ras mutations, point mutation of CAA to CGA in codon 61, were detected in one follicular adenoma (12.5%, 1/8) and one follicular carcinoma (33%, 1/3). p53 mutations were detected in only one case of papillary carcinoma (3%, 1/31: exon 8, codon 266 GGA-->GAA). In 30 cases of papillary carcinoma without p53 mutation, the prevalences of positive immunohistochemical staining were 13.3% for p53 protein, 53.3% for MDM2 protein and 56.7% for Bcl-2 protein. While over-expression of p53 protein was not significantly related to that of MDM2 and Bcl-2 proteins, over-expression of MDM2 and Bcl-2 in papillary carcinoma were associated.

CONCLUSION

ret/PTC rearrangement, Gs alpha, ras and p53 mutations are relatively rare in differentiated thyroid neoplasms from a Korean population, which may reflect genetic and environmental differences from patients in countries with high prevalences. P53 protein over-expression was noted in 13.3% of papillary carcinoma cases without p53 mutation and was not significantly related to MDM2 and Bcl-2 expression.

Mechanisms of the inhibition by neostigmine of tetanic contraction in the mouse diaphragm

Neostigmine (0.5-2 microM) caused fade of tetanic contractions (Wedensky inhibition) evoked by repetitive nerve stimulation. The mechanism underlying this action was studied in intact and cut isolated phrenic nerve-diaphragm preparations of mice. The fade was brought about by failure to elicit muscle action potentials. During fade, the muscle was unable to conduct directly evoked action potentials across the central endplate zone. Recovery of excitability occurred in 5 s with continued stimulation. In the presence of neostigmine, the resting membrane potential at endplate areas during repetitive stimulation decreased from -80 mV to less than -50 mV within the first 10 pulses at 75-200 Hz and thereafter recovered gradually to about -60 mV in the following 5 s during continuous stimulation. The quantal content of endplate potentials evoked by single stimulation was not reduced by neostigmine whereas that evoked by high frequency stimuli (75 Hz) was reduced to about 1/3 in 10 pulses. It is concluded that the fade of tetanic contraction caused by inhibition of acetylcholinesterase is induced by the inactivation of sodium channels in the area surrounding the endplates and that the sustained fade is due to a decrease of transmitter release. Both effects are the result of acetylcholine accumulation.

Expressions of human sodium iodide symporter mRNA in primary and metastatic papillary thyroid carcinomas

The sodium iodide symporter (NIS) is a plasma membrane protein that is responsible for iodide transport into thyroid cells. To understand the regulation and expression of human NIS (hNIS) in papillary thyroid carcinomas, we evaluated the expression levels of hNIS mRNA in primary and lymph node metastatic papillary carcinoma tissues. The correlation of mRNA levels between hNIS and thyroid-specific genes, thyrotropin (TSH) receptor, and thyroglobulin (Tg), were also investigated. Twenty-three cases of papillary carcinoma and 7 pairs of primary and lymph node metastastic tissues were included in this study. We measured the expression levels of hNIS, TSH receptor, and Tg mRNAs by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and RNase protection assay (RPA). The levels of hNIS mRNA in lymph node metastatic tissues were evaluated by RT-PCR. By semiquantitative RT-PCR, 87% of papillary carcinoma (20/23) expressed hNIS mRNA, but the degrees of expression were variable and were lower than those of normal thyroid tissues. The decreased expression of hNIS mRNA in papillary carcinoma compared to normal thyroid tissue was also noticed by RPA. All 23 papillary carcinomas in this study showed the expression of TSH receptor and Tg mRNAs. The levels of TSH receptor mRNA were again lower in papillary thyroid carcinomas than in normal controls. The level of hNIS mRNA was correlated with the levels of TSH receptor (r = 0.449, p < 0.05), but not with Tg mRNA. In addition, significant correlation of mRNA level was observed between TSH receptor and Tg (r = 0.706, p < 0.01). Two of six lymph node metastatic tissues did not show hNIS mRNA even with significant hNIS expressions in papillary carcinoma tissues in thyroid. The levels of hNIS expression of the remaining four lymph node metastatic tissues were lower than those of corresponding primary tissues. Interestingly, one case showed no hNIS expression in primary tissue, but significant hNIS expression in lymph node metastatic tissue. No correlation was found in hNIS mRNA expression between primary and lymph node metastatic tissues. Our results suggest that the measurements of hNIS mRNA level in primary tissues may not predict the therapeutic response to radioactive iodine.

Toxic effects of mitomycin-C on cultured corneal keratocytes and endothelial cells

Improper use of mitomycin-C in ocular medication may result in damage to corneal cells. In this study, the toxic effects of mitomycin-C on cultured porcine keratocytes and endothelial cells were estimated by MTT, 3H-thymidine uptake and cellular counting assay methods. It was found that mitomycin-C caused a dose-dependent toxic effect to keratocytes and endothelial cells. Both cells were treated with mitomycin-C at the concentration ranging from 100, 10, 1, 0.1 to 0.01 microg/ml for 3 min, 5 min or 100 min. The 50% inhibitory dose (ID50) of mitomycin-C to keratocytes and endothelial cells as measured by MTT assay was 0.40, 0.18, 0.16 mg/ml and 0.27, 0.15, 0.14 mg/ml, respectively, after 3, 5 and 100 minutes drug treatment. The ID50 for keratocytes and endothelial cells as measured by 3H-thymidine uptake immediately, 1 day and 7 days after 100 minutes mitomycin-C treatment was 0.3, 0.0002, 143.2 microg/ml and 45.1, 101.1, 450.2 microg/ml, respectively. The ID50 for keratocytes and endothelial cells as measured by cellular counting 1 day and 7 days after mitomycin-C treatment was 232.5, 109.7 microg/ml and 239.9, 367.5 microg/ml, respectively. It is concluded that mitomycin-C is more toxic to cellular proliferation in cultured corneal keratocytes than in endothelial cells.

Prevalence of atopy and allergic diseases in Korean children: associations with a farming environment and rural lifestyle

BACKGROUND

The results of recent studies suggest that factors in rural environments may protect against the development of allergic diseases, but the underlying mechanisms are not well understood. The aim of this study was to investigate the prevalence of allergic diseases, to establish if this prevalence is influenced by migration from rural to urban areas and to identify environmental risk factors associated with these diseases.

METHODS

A cross-sectional study of children aged 9-12 years from a rural village, a rural town and an urban city in Korea was conducted. Demographic and disease-related information was obtained via a detailed questionnaire, and skin prick tests were performed.

RESULTS

There were significant differences in lifestyle and environmental factors between children from the rural village, the rural town and the urban children. The prevalence of allergic diseases and atopy was higher in urban children. A lower prevalence of allergic diseases and atopy was associated with farming parents, contact with farm animals during pregnancy, owning pets or a stable, breast-feeding and having older siblings. A comparison of rural village and rural town children revealed no evidence of an association of allergic diseases and atopy with farming parents, contact with farm animals during pregnancy or owning a stable. On the other hand, having older siblings and antibiotic use during infancy were significantly associated with allergic diseases and atopy in these children.

CONCLUSIONS

Protective factors associated with a farming environment and/or rural lifestyle may influence the prevalence of allergic diseases and atopy in Korean children.

Through-the-scope double colonic stenting in the management of inoperable proximal malignant colonic obstruction: a pilot study

BACKGROUND AND STUDY AIMS

Particularly in cases of proximal colonic obstruction, the long distance and tortuosity of the bowel make it difficult for gastroenterologists and radiologists to advance the stent to the point of the obstruction. The purpose of this study was to evaluate the clinical usefulness and efficacy in preventing stent migration and tumor ingrowth of a new self-expanding through-the-scope (TTS) double colonic stent in the palliative management of patients with inoperable proximal malignant colonic obstruction.

PATIENTS AND METHODS

A total of seven patients (four men, three women; mean age 62 years, range 57 - 68) underwent placement of a newly developed through-the-scope self-expanding double colonic stent. The etiologies of the obstructions at the time of stent insertion were colonic adenocarcinoma (no previous surgical resection) in five cases and metastatic adenocarcinoma from gastric carcinoma in two. The locations of the obstructions were the ascending colon in three cases, the hepatic flexure in two, and the transverse colon in two. To prevent tumor ingrowth and stent migration, an uncovered Niti-S stent (Taewoong Medical Co., Ltd., Seoul, South Korea) was inserted into the stenotic area; a partly membrane-covered Niti-S stent was then again inserted into the stenotic area inside the uncovered Niti-S stent.

RESULTS

The self-expanding TTS double colonic stents were placed in the colon in seven patients with acute malignant colonic obstruction. Double stenting was successful in traversing the lesion in six of the seven cases. In one patient, the stent was not successfully placed across the lesion due to a very acute angle at the hepatic flexure. There were no significant complications relating to the insertion, with no clinical or radiographic evidence of perforation or bleeding during or after the procedures, and there were no cases of stent migration or tumor ingrowth during the mean follow-up period of 13 months.

CONCLUSIONS

Placement of these new self-expanding through-the-scope double colonic stents for the management of inoperable proximal malignant colonic obstruction is a feasible, effective, and safe form of palliative treatment for the prevention of stent migration and tumor ingrowth.

Phenylephrine-induced Ca2+ oscillations in canine pulmonary artery smooth muscle cells

Modulation of [Ca2+]i in response to receptor activation is a critical determinant of vascular smooth muscle tone. In this study, we examined the effect of continuous stimulation of alpha 1-adrenoceptors with phenylephrine (PE) on [Ca2+]i in single pulmonary artery smooth muscle cells (PASMCs) cultured from explants of canine intrapulmonary artery. Fura 2-loaded PASMCs pretreated with propranolol (5 mumol/L) were continuously superfused with PE at 37 degrees C on the stage of an inverted fluorescence microscope, and [Ca2+]i was measured using a dual-wavelength spectrofluorometer. Resting values of [Ca2+]i were 96 +/- 4 nmol/L. PE (10 mumol/L) stimulated oscillations in [Ca2+]i at a frequency of 1.35 +/- 0.07/min, which reached a peak [Ca2+]i of 650 +/- 26 nmol/L (n = 69 cells). The oscillations lasted for > 30 minutes and were constant in amplitude and frequency. Both the amplitude and frequency of PE-induced [Ca2+]i oscillations increased in a dose-dependent (3 x 10(-8) to 10(-4) mol/L) manner. Pretreatment with the alpha 1-adrenoceptor antagonist prazosin (50 nmol/L) or removal of extracellular Ca2+ abolished the repetitive [Ca2+]i oscillations induced by PE. The voltage-operated Ca2+ channel blockers nifedipine (1 mumol/L) and verapamil (1 mumol/L) had no effect on the [Ca2+]i oscillations. In contrast, inhibition of phospholipase C with U73122 (10(-7) to 10(-5) mol/L) attenuated the oscillations in a dose-dependent fashion. The nonselective protein kinase inhibitor staurosporine (10(-9) to 10(-7) mol/L) had a minimal inhibitory effect on the oscillations. Caffeine (30 mmol/L) and thapsigargin (1 mumol/L) abolished the oscillations, whereas pretreatment with ryanodine (1 to 100 mumol/L) had no effect. In freshly dispersed PASMCs, PE (10 mumol/L) induced oscillations in [Ca2+]i similar to those observed in cultured cells, and patch-clamp experiments revealed oscillations in membrane potential. These results indicate that PE induces [Ca2+]i oscillations in PASMCs via stimulation of alpha 1-adrenoceptors coupled to phospholipase C activation. Voltage-operated Ca2+ channels and protein kinases are not required for the oscillations. The requirement for extracellular Ca2+ and intracellular Ca2+ stores indicates that both Ca2+ influx and intracellular Ca2+ release play a role in the maintenance of the oscillations.

Clonorchis sinensis: molecular cloning and characterization of 28-kDa glutathione S-transferase

A 28-kDa glutathione S-transferase (Cs28GST) was purified from a Clonorchis sinensis cytosolic fraction through anion-exchange and glutathione-affinity column chromatographies. A monoclonal antibody raised against Cs28GST reacted specifically to the C. sinensis antigen among trematode proteins. A putative peptide of 212 amino residues deduced from a cDNA clone appeared homologous with 28-kDa GST of trematodes, and its secondary structural elements predicted a GSH-binding site. Recombinant Cs28GST showed GST enzyme activity with CDNB substrate and was sensitive to the model inhibitors. The recombinant Cs28GST was antigenically indistinguishable from the native form and was recognized specifically by C. sinensis-infected human sera. The Cs28GST was localized in the tegument and underlying mesenchymal tissues. It is suggested that Cs28GST may play significant physiological roles against bioreactive molecules and be a useful reagent for serodiagnosis of clonorchiasis.

F-18-fluorodeoxyglucose positron emission tomography as a presurgical evaluation modality for I-131 scan-negative thyroid carcinoma patients with local recurrence in cervical lymph nodes

BACKGROUND

F-18-labeled fluorodeoxyglucose-positron emission tomography (FDG-PET) has a supplementary role in localizing recurrent sites of differentiated thyroid carcinoma. We evaluated whether FDG-PET is feasible as a presurgical evaluation modality for I-131 scan-negative thyroid carcinoma patients.

METHODS

Preoperative FDG-PET results were compared with the pathologic findings of lymph nodes specimens of 22 papillary thyroid patients. All patients had thyroidectomy and I-131 ablation therapy beforehand and showed negative I-131 scans on follow-up studies.

RESULTS

In 85 cervical lymph node groups dissected, 56 lymph node groups revealed metastasis. The sensitivity and specificity of FDG PET for metastasis were 80% (45 of 56) and 83% (24 of 29), respectively. Among the pathologically positive 33 lymph nodes with normal size(< or =1 cm), FDG-PET detected 23 nodes. Serum thyroglobulin levels were elevated in 12 patients (sensitivity, 55%).

CONCLUSION

FDG-PET accurately detected the recurred cervical lymph nodes of differentiated thyroid carcinoma patients who showed negative I-131 scan. FDG-PET is suitable for the presurgical evaluation of these patients.

Calcium channel subtypes for the sympathetic and parasympathetic nerves of guinea-pig atria

1. The Ca2+ channel subtypes of the autonomic nerves of guinea-pig atria were elucidated by monitoring the effects of specific Ca2+ channel blockers on the negative and positive inotropic responses associated respectively, with stimulation of the parasympathetic and sympathetic nerves. 2. In left atria paced at 2-4 Hz, the negative inotropic effect induced by field stimulation of parasympathetic nerves (in the presence of propranolol) was abolished by omega-conotoxin MVIIC, a blocker of N-type and OPQ subfamily Ca2+ channels. omega-Conotoxin GVIA (an N-type blocker), omega-agatoxin IVA (a P-type blocker), nifedipine (an L-type blocker) and Ni2+ (a T- and R-type blocker) were much less effective. 3. The positive inotropic response resulting from field stimulation of the sympathetic nerves (in the presence of atropine) was abolished by both omega-conotoxins, while omega-agatoxin IVA, nifedipine and Ni2+ were ineffective. 4. In the spontaneously beating right atria, the early negative inotropic effect produced by 1,1-dimethyl-4-phenylpiperazinium was abolished by omega-conotoxin MVIIC, whereas the late positive inotropic effect was partially reduced, but not abolished, by a high concentration of omega-conotoxin GVIA. 5. None of the peptide toxins affected the chronotropic and the inotropic responses evoked by carbachol and isoprenaline. 6. These results suggested that, under physiological conditions, the release of acetylcholine from parasympathetic nerves is dominated by an OPQ subfamily Ca2+ channel while that of noradrenaline from sympathetic nerves is controlled by an N-type Ca2+ channel. Ligand-induced noradrenaline release appeared to recruit additional type(s) of Ca2+ channel.