High critical current density and enhanced irreversibility field in superconducting MgB2 thin films

The discovery of superconductivity at 39 K in magnesium diboride offers the possibility of a new class of low-cost, high-performance superconducting materials for magnets and electronic applications. This compound has twice the transition temperature of Nb3Sn and four times that of Nb-Ti alloy, and the vital prerequisite of strongly linked current flow has already been demonstrated. One possible drawback, however, is that the magnetic field at which superconductivity is destroyed is modest. Furthermore, the field which limits the range of practical applications-the irreversibility field H*(T)-is approximately 7 T at liquid helium temperature (4.2 K), significantly lower than about 10 T for Nb-Ti (ref. 6) and approximately 20 T for Nb3Sn (ref. 7). Here we show that MgB2 thin films that are alloyed with oxygen can exhibit a much steeper temperature dependence of H*(T) than is observed in bulk materials, yielding an H* value at 4.2 K greater than 14 T. In addition, very high critical current densities at 4.2 K are achieved: 1 MA cm-2 at 1 T and 105 A cm-2 at 10 T. These results demonstrate that MgB2 has potential for high-field superconducting applications.

Inhibition of cytokine-induced vascular cell adhesion molecule-1 expression; possible mechanism for anti-atherogenic effect of Agastache rugosa

Adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1) play an important role during the early stages of atherogenesis. Agastache rugosa has an anti-atherogenic effect in low density lipoprotein receptor -/- mice. Moreover, A. rugosa reduced macrophage infiltration and VCAM-1 expression has been localized in aortic endothelium that overlies early foam cell lesions. This study ascertained that tilianin (100 microM), a major component of A. rugosa, inhibits the tumor necrotic factor-alpha (TNF-alpha)-induced expression of VCAM-1 by 74% in cultured human umbilical vein endothelial cells (HUVECs). Also, tilianin (100 microM) reduced TNF-alpha-induced activation of nuclear factor-kappaB in HUVECs.

Platelet-activating factor-induced early activation of NF-kappa B plays a crucial role for organ clearance of Candida albicans

In this study, we have investigated the mechanisms underlying organ susceptibility to candida infection. Infection of BALB/c mice with Candida albicans led to both an early (1-8 h) and late (24-48 h) activation of NF-kappaB in the organs resistant to C. albicans, including the lung and spleen. In susceptible organs such as the kidneys, early activation of NF-kappaB was not observed. The kinetics of TNF-alpha mRNA expression paralleled those of NF-kappaB activation in all organs examined. Blocking the effects of endogenous platelet-activating factor (PAF) by pretreatment with the PAF antagonist BN50739 or antioxidants significantly reduced the early activity of NF-kappaB and TNF-alpha mRNA expression, and increased the recovery of C. albicans in the lung and spleen. Importantly, administration of PAF 5 min prior to the infection resulted in the appearance of early activities of NF-kappaB and TNF-alpha mRNA expression, followed by a nearly complete clearance of the organisms in the kidneys. Pretreatment with anti-TNF-alpha Ab resulted in an enhanced susceptibility to C. albicans, and the PAF-mediated resistance was abrogated by anti-TNF-alpha in all organs examined. These data indicated that endogenously produced PAF in response to C. albicans is a key molecule involved in the early activation of NF-kappaB, which, in turn, renders the organ resistant to the fungus by promoting the production of anti-candidal proinflammatory cytokines such as TNF-alpha. Susceptible organs, including the kidneys, lack the capacity to generate a sufficient PAF-induced early NF-kappaB response.

Graves' disease presenting as elephantiasic pretibial myxedema and nodules of the hands

A 67-year-old man presented with a 2-year history of asymptomatic, firm, multiple nodules and plaques and cerebriform hypertrophy of both lower legs and feet, and well-defined, skin-colored, firm nodules and tumors on both hands. He had been diagnosed as having Graves' disease 3 years previously, and had been treated with 10 mg of methimazole and 100 microg of thyroxin (T4) daily for 2 years. Physical examination revealed nonpitting edema, flesh-colored to erythematous, firm, confluent, polypoid nodules and fissured plaques extending from the shins to the dorsa of both feet (Fig. 1), and round to oval, firm, skin-colored, walnut-to-egg-sized tumors on all 10 fingers and the ulnar side of the dorsum of the right hand (Fig. 2). The thyroid gland was diffusely enlarged; however, there was no exophthalmos, and extraocular movements were normal. There was no weight loss, loss of appetite, tremor, heat intolerance, diarrhea, or fatigue. On laboratory evaluation, thyroid-stimulating hormone (TSH) had a markedly low titer of < 0.05 microU/mL (normal: 0.4-5.0), and the TSH receptor antibody was extremely high at 73.8% (normal: < 15%). Serum free triiodothyronine (T3), T4, antimicrosome, and antithyroglobulin antibodies were normal or negative. Skin biopsy samples from the shin and hand disclosed extensive mucin deposition throughout the dermis.

Prevalence of endoscopic reflux esophagitis among Koreans

BACKGROUND AND AIM

Although reflux esophagitis is believed to be common in the Western population, very few epidemiologic data on reflux esophagitis in Koreans are available. The aims of this study were to evaluate the prevalence of endoscopic reflux esophagitis in patients who came for a physical check-up at Korea University Hospital, and to study the relationship between various factors relevant to reflux disease.

METHODS

This study was carried out prospectively on 7,015 patients who received an esophagogastroduodenoscopy from September 1996 to December 1997. Most of the patients were free of symptoms and had come for their self-paid check-up.

RESULTS

The overall prevalence of reflux esophagitis was 3.4%, and most of the patients had a mild degree of esophagitis representing grade 1 in 98.3% and grade 2 in 1.7%. The male: female ratio for esophagitis was 7 : 1, and the body mass index (BMI) was significantly higher in patients with reflux esophagitis. A hiatal hernia was found in 166 patients with esophagitis (68.6%), but only in 9.2% patients without esophagitis (P < 0.05). Smoking and alcohol consumption were associated with the development of reflux esophagitis (P < 0.05).

CONCLUSIONS

The prevalence of endoscopic reflux esophagitis among Koreans is 3.4%, and most of the patients had a mild grade esophagitis. Smoking, alcohol consumption, the presence of a hiatal hernia and a higher BMI are associated with the development of reflux esophagitis.

Vitamin E improves microsomal phospholipase A2 activity and the arachidonic acid cascade in kidney of diabetic rats

The purpose of the present study was to investigate the effects of vitamin E on microsomal phospholipase A2 activity and the arachidonic acid cascade in the kidneys of streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal and three STZ-induced diabetic groups. The diabetic groups were fed a vitamin E-free diet (the DM-0E group), 40 mg vitamin E/kg diet (the DM-40E group) or a 400 mg vitamin E/kg diet (the DM-400E group). The kidney vitamin E concentrations were 59 and 49% lower in the DM-0E and DM-40E groups, respectively, than in the normal group. The kidney thiobarbituric acid reactive substance concentrations in the DM-0E, DM-40E and DM-400E groups were 119, 84 and 33% greater, respectively, than that in the normal group. The concentration in the DM-400E group was 39% lower than that in the DM-0E group. The phospholipase A2 (PLA2) activity in the kidney microsomes of the DM-0E-40E and DM-400E groups were 88, 58 and 35% greater, respectively, than that in the normal group. The activity in the DM-400E group was 28% lower than that in the DM-0E group and 16% lower than that in the DM-40E group. The differences in the phospholipids in the kidney microsomes included reductions in the phosphatidylcholine and phosphatidylethanolamine compositions. Phosphatidylethanolamine hydrolysis in the kidney microsomes of the DM-0E and DM-40E groups were 84 and 64%, which did not differ from the DM-400E group. The formation of thromboxane A2 (TXA2) in the kidney microsomes was 137 and 70% greater in the DM-0E and DM-40E groups, respectively, than in the normal group. TXA2 formation did not differ between the DM-400E and normal groups. The formation of prostacyclin in the kidney microsomes was 60 and 44% lower in the DM-0E and DM-40E groups, respectively, than in the normal group, whereas the DM-400E group did not differ from that in the normal group. The ratio of prostacyclin to TXA2 was 82 and 65% lower than normal in the DM-0E and DM-40E groups, respectively. Kidney function appears to be improved by vitamin E supplementation due to its antithrombus action, which in turn controls the arachidonic acid cascade system.

Investigation of human brain hemodynamics by simultaneous near-infrared spectroscopy and functional magnetic resonance imaging

The aim of this study was to compare functional cerebral hemodynamic signals obtained simultaneously by near infrared spectroscopy (NIRS) and by functional magnetic resonance imaging (fMRI). The contribution of superficial layers (skin and skull) to the NIRS signal was also assessed. Both methods were used to generate functional maps of the motor cortex area during a periodic sequence of stimulation by finger motion and rest. In all subjects we found a good collocation of the brain activity centers revealed by both methods. We also found a high temporal correlation between the BOLD signal (fMRI) and the deoxy-hemoglobin concentration (NIRS) in the subjects who exhibited low fluctuations in superficial head tissues.

Effects of age and dietary restriction on lifespan and oxidative stress of SAMP8 mice with learning and memory impairments

This study was to evaluate the effect of dietary restriction (DR) on lifespan and oxidative stress of dementia mouse model SAMP8 with impaired learning and memory. SAMP8 female mice were fed either ad libitum (AL) or fed 60% of food intake of AL. Results showed that basal metabolic rates (BMR) were significantly lower (15 to 22%) in DR with increased median and maximum lifespans, suggesting feed and gross efficiencies were significantly lower in DR than in AL. Grading score of senescence resulted in a marked improvement about 2-fold by DR compared with AL. The amounts of lipofuscin at 12 months were significantly lowered 16% in DR than that of AL. Median and maximal lifespans significantly increased (28.5% and 16.4%, respectively) by DR, and also lowered superoxide radical about 15 approximately 45% in DR compared with AL at 4, 8 and 12 months of age. On the other hand, superoxide dismutase (SOD) activities were higher (about 15 approximately 30%) in DR than those in AL group of SAMP8 except for 4 months of age. Our results suggest that 40% calorie restricted SAMP8 can effectively suppress dementia-related abnormalities during aging.

Detection of malignant cells in pleural fluid or ascites by CD44v8-10/CD44v10 competitive RT-PCR

BACKGROUND

CD44 is a cell surface adhesion molecule which has been implicated in various biologic functions as lymphocyte homing and activation, cellular migration and extracellular matrix adhesion. Over-expression of CD44v8-10 has been found in several cancers and is considered to be associated with tumor progression and metastasis. Recently, a novel molecular method, CD44v8-10/CD44v10 competitive reverse transcription-polymerase chain reaction(RT-PCR) has been developed for detecting cancer cells over-expressing CD44v8-10.

METHODS

We analyzed from benign and malignant pleural effusion and ascites by CD44 competitive RT-PCR and compared to the conventional cytology.

RESULTS

The CD44 competitive RT-PCR analysis showed that all the 24 samples associated with benign disease presented a predominant expression of the CD44v10 transcript (v8-10/v10 ratio: 0.126-0.948), whereas 6 of 7 malignant pleural samples associated with cytology positive cancer expressed the CD44v8-10 transcript (v8-10/v10 ratio > 1.00).

CONCLUSION

These results indicate that CD44 competitive RT-PCR assay is a useful and adjunct to cytological examination in cancer diagnosis, especially in detecting exfoliated cancer cells in pleural effusion.

Hematein inhibits tumor necrotic factor-alpha-induced vascular cell adhesion molecule-1 and NF-kappaB-dependent gene expression in human vascular endothelial cells

Monocyte adhesion to the endothelium via adhesion molecules is one of the earliest events in atherogenesis. It has been suggested that vascular cell adhesion molecule-1 (VCAM-1) plays a very important role in the recruitment of monocytes in atherosclerosis. The aim of our study was to evaluate whether hematein can influence the expression of VCAM-1 and the transcription of nuclear factor-kappaB (NF-kappaB)-dependent genes. Immunohistochemistry revealed that mouse aortic artery endothelial cells express VCAM-1 after feeding a high cholesterol diet for 8 weeks. Hematein dose dependently suppressed TNF-alpha-induced VCAM-1 in both surface (30.8%) and soluble protein (65%) production in HUVECs. The transcription level of VCAM-1 was measured by Northern blot analysis, and decreased VCAM-1 protein expression was associated with a reduction of VCAM-1 mRNA expression. Transient transfection study of NF-kappaB promoter construct and electrophoretic mobility shift assay suggested that hematein inhibited both NF-kappaB-dependent gene expression and NF-kappaB activation induced by TNF-alpha. Our results suggest that the down-regulation of VCAM-1 expression by hematein may in part be due to the inhibition of NF-kappaB-dependent gene expression.

Glucocorticoid-mediated repression of inflammatory cytokine production in fibroblast-like rheumatoid synoviocytes is independent of nuclear factor-kappaB activation induced by tumour necrosis factor alpha

OBJECTIVE

To determine whether steroids inhibit the production of inflammatory cytokines by the inhibition of nuclear factor kappaB (NF-kappaB) activation in fibroblast-like rheumatoid synoviocytes (FLSs) under inflammatory conditions, and to determine whether steroids stimulate the induction of synthesis of the inhibitory protein IkappaB-alpha in the anti-inflammatory immune response of these cells.

METHODS

Expression of the interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) genes was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), and the secreted IL-6 was measured with the enzyme-linked immunosorbent assay. Inhibition of the NF-kappaB activation was examined with the electrophoretic mobility shift assay (EMSA). In order to study dexamethasone (DEX)-dependent regulation of IkappaB-alpha expression, we performed Western blotting before and after stimulation with tumour necrosis factor alpha (TNF-alpha).

RESULTS

The inflammatory cytokine study showed that DEX suppressed gene expression and the production of protein in FLSs. EMSA demonstrated that identical amounts of NF-kappaB were present in the nucleus of the FLSs stimulated by TNF-alpha, with or without pretreatment with DEX. Treatment of FLSs with DEX did not induce an increase in IkappaB-alpha sufficient to prevent nuclear translocation of NF-kappaB on stimulation with TNF-alpha.

CONCLUSION

DEX may suppress the production of inflammatory cytokines, such as IL-6 and IL-1beta, but it neither prevents the translocation of NF-kappaB to the nucleus nor induces the synthesis of IkappaB-alpha protein in FLSs stimulated by TNF-alpha.

Modulation of age-related alterations of iron, ferritin, and lipid peroxidation in rat brain synaptosomes

Oxidative stress, as indicated by increases in lipid peroxidation, is generally found to increase with age. Also found in various tissues of aged organisms, including the brain, is the accumulation of iron, a pro-oxidant transition metal. In this study, iron content and ferritin levels were measured in the synaptosomes isolated from the frontal cortices of aged male Fischer 344 rats. Age-related changes in lipid peroxide and the peroxidizability of synaptosomal fatty acids were also studied in addition to the anti-aging effect of dietary restriction (DR) (60% food intake of ad libitum (AL) fed animals) on the modulation of age-related iron status and lipid peroxidation. When comparing the two dietary groups for the age-related production of reactive oxygen species (ROS), DR was shown to effectively suppress the amount of age-related ROS in the brain synaptosomes of these rats. Increases in lipid peroxide and accumulations of total iron and ferritin in brain synaptosomes of DR rats were also shown to be significantly lower than those of AL rats. Increased lipid peroxide and accumulated iron overload were effectively attenuated by DR, and the modulation of synaptosomal iron status was consistent with previous findings on the anti-aging action of DR.

The effects of dietary restriction on age-related changes in rat serum prostaglandins

This study investigated whether or not dietary restriction (DR), consisting of 60% of the daily caloric allowance of ad libitum fed (AL) rats, has a modulating effect on prostaglandins (PGs), thromboxane (TXA), and lipids in the serum of rats. Results showed that DR rats had consistently, 30-40% lower overall lipid peroxide levels than AL rats. On the other hand, the age-related increases in arachidonic acid contents observed in AL rats were significantly suppressed by DR during aging; while unsaturated/saturated fatty acid ratios remained consistently higher (15-50%) in DR rats than in AL rats. Serum PGE2 and PGF2 levels in DR rats were maintained at consistently higher levels (30-65% and 40-90%, respectively) than in AL rat serum. PGI2 levels (as measured by 6-keto PGF2) in serum of DR rats were also consistently higher (40-50%) than those of AL rats, while TXA2 levels sustained lower levels (15-20%) than those of AL rats, showing a significantly higher (27-38%) PGI2/TXA2 ratios in DR than in AL rats. Thus, our study clearly indicated that DR effectively modulates prostaglandin levels by preventing age-related decreases in PGI2 levels and increases in TXA2 levels. These findings, with the other known beneficial actions of DR, strongly suggest vascular activity to be well-regulated in DR animals.

Dietary restriction as a modulator of age-related changes in rat kidney prostaglandin production

Prostaglandin (PG) levels in kidney glomeruli isolated from rats under the dietary restriction (DR) regimen were investigated beginning at 6 weeks of age. The modulation of age and DR on PGs, thromboxane (TXA), and their precursor fatty acids were documented for PGE2, PGF2, 6 keto-PGF1, and TXA2 status in aged kidney. The results show that PGE2 and PGF2 production by the glomeruli of DR rats were consistently higher (10-17% and 11-25%, respectively) than in those of AL rats. Although levels of the potent vasodilator, PGI2 (as determined by 6 keto-PGF1,) were shown to decrease after 12 months of age in AL rats, steady levels were shown throughout life in DR rats. In contrast, levels of the typical vasoconstrictor, TXA2, were markedly elevated in AL rats compared to DR rats. As a consequence, PGI2/TXA2 ratios were shown to be decreased in AL rats, while remaining well-maintained in DR rats throughout lifespan. These results indicate that the life-prolonging action of DR attenuates age-related prostaglandin imbalances to preserve and maintain the autoregulation of the glomerular filtration rate (GFR) and other related kidney functions.

Excision repair of adozelesin-N3 adenine adduct by 3-methyladenine-DNA glycosylases and UvrABC nuclease

Adozelesin is a synthetic analog of the antitumor antibiotic CC-1065, which alkylates the N3 of adenine in the minor groove in a sequence-selective manner. Since the cytotoxic potency of a DNA alkylating agent can be modulated by DNA excision repair system, we investigated whether nucleotide excision repair (NER) and base excision repair (BER) enzymes are able to excise the bulky DNA adduct induced by adozelesin. The UvrABC nuclease and 3-methyladenine-DNA glycosylase, that exhibit a broad spectrum of substrate specificity, were selected as typical NER and BER enzymes, respectively. The adozelesin-DNA adduct was first formed in the radiolabeled restriction DNA fragment and its excision by purified repair enzymes was monitored on a DNA sequencing gel. The treatment of the DNA adduct with a purified UvrABC nuclease and sequencing gel analysis of cleaved DNA showed that UvrABC nuclease was able to incise the adozelesin adduct. The incision site corresponded to the general nuclease incision site. Excision of this adduct by 3-methyladenine-DNA glycosylases was determined following the treatment of the DNA adduct with a homogeneous recombinant bacterial, rat and human 3-methyladenine-DNA glycosylases. Abasic sites generated by DNA glycosyalses were cleaved by the associated lyase activity of the E. coli formamidopyrimidine-DNA glycosylase (Fpg). Resolution of cleaved DNA on a sequencing gel showed that the DNA glycosylase from different sources could not release the N3-adenine adducts. A cytotoxicity assay using E. coli repair mutant strains showed that E. coli mutant strains defective in the uvrA gene were more sensitive to cell killing by adozelesin than E. coli mutant strain defective in the alkA gene or the wild type. These results suggest that the NER pathway seems to be the major excision repair system in protecting cells from the cytotoxicity of adozelesin.

Proteolytic cleavage of epidermal growth factor receptor by caspases

Apoptotic proteases cleave and inactivate survival signaling molecules such as Akt/PKB, phospholipase C (PLC)-gamma1, and Bcl-2. We have found that treatment of A431 cells with tumor necrosis factor-alpha in the presence of cycloheximide resulted in the cleavage of epidermal growth factor receptor (EGFR) as well as the activation of caspase-3. Among various caspases, caspase-1, caspase-3 and caspase-7 were most potent in the cleavage of EGFR in vitro. Proteolytic cleavage of EGFR was inhibited by both YVAD-cmk and DEVD-fmk in vitro. We also investigated the effect of caspase-dependent cleavage of EGFR upon the mediation of signals to downstream signaling molecules such as PLC-gamma1. Cleavage of EGFR by caspase-3 significantly impaired the tyrosine phosphorylation of PLC-gamma1 in vitro. Given these results, we suggest that apoptotic protease specifically cleaves and inactivates EGFR, which plays crucial roles in anti-apoptotic signaling, to abrogate the activation of EGFR-dependent downstream survival signaling molecules.

Idiopathic eruptive macular pigmentation: report of 10 cases

Idiopathic eruptive macular pigmentation (IEMP) is a rare disease. IEMP is characterized by asymptomatic, pigmented macules involving the neck, trunk, and proximal extremities. This study describes 10 cases of idiopathic eruptive macular pigmentation seen during a 9-year period at the Asan Medical Center, Seoul, Korea. We present these characteristic consecutive cases to provide more insight into the clinical picture and course of IEMP. Skin lesions of 8 patients were multiple brown macules involving the trunk, face, neck, and extremities. In 2 patients, multiple dark brown macules and patches were noted. The age of onset varied from 1 to 20 years. Tentative diagnoses were usually ashy dermatosis (erythema dyschromicum perstans), fixed drug eruption, or mastocytosis. The history of any erythema and drug medication was absent. Darier's sign was absent. Skin biopsy specimens showed increased pigmentation of the basal layer in an otherwise normal epidermis. Pigmentary incontinence, melanophages, and mild perivascular lymphohistiocytic infiltrate in the papillary dermis were also revealed. Mast cells could not be found. The lesions gradually disappeared during a period of several months to years. The alleged rarity of IEMP may be partially caused by medical unfamiliarity with this entity, despite its clinical and histopathologic characteristic picture. Treatment of IEMP is unnecessary because spontaneous resolution of the lesions can be expected within several months to a few years.

Constituents and the antitumor principle of Allium victorialis var. platyphyllum

To search for cytotoxic components from Allium victorialis, MTT assays on each extract and an isolated component, gitogenin 3-O-lycotetroside, were performed against cancer cell lines. Cytotoxicities of most extract were shown to be comparatively weak, though IC50 values of CHCl3 fraction was found to be <31.3-368.4 microg/ml. From the incubated methanol extract at 36 degrees C, eleven kinds of organosulfuric flavours were predictable by GC-MS performance. The most abundant peak was revealed to be 2-vinyl-4H-1,3-dithiin (1) by its mass spectrum. Further, this extract showed significant cytotoxicities toward cancer cell lies. Silica gel column chromatography of the n-butanol fraction led to the isolation of gitogenin 3-O-lycotetroside (3) along with astragalin (4) and kaempferol 3, 4'-di-O-beta-D-glucoside (5). This steroidal saponin exhibited significant cytotoxic activities (IC50, 6.51-36.5 microg/ml) over several cancer cell lines. When compound 3 was incubated for 24 h with human intestinal bacteria, a major metabolite was produced and then isolated by silica gel column chromatography. By examining parent- and prominent ion peak in FAB-MS spectrum of the metabolite, the structure was speculated not to be any of prosapogenins of 3, suggesting that spiroketal ring were labile to the bacterial reaction. These suggest that disulfides produced secondarily are the antitumor principles.

Clinical significance of microvessel density in multiple myeloma patients

To investigate the role of angiogenesis in multiple myeloma (MM), bone marrow biopsy from 75 adults with newly diagnosed, untreated MM were evaluated. Microvessels were scored in at least 3 areas ( x 200 fields) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for CD34. Prognostic variables were also evaluated for the overall survival. Microvessel counts were significantly higher in patients with MM (n=69.42+/-9.67), compared with control (n=26.81+/-2.85). Microvessel density had a weak correlation with percentage of bone marrow plasma cells. By univariate analysis, age, beta2-microglobulin, serum albumin, serum creatinine, serum calcium, hemoglobin, platelet count, and bone marrow plasma cell percentage were correlated with survival. By multivariate analysis, age, serum albumin, serum creatinine, hemoglobin, platelet count and bone marrow plasma cell percentage were correlated with overall survival, whereas microvessel density was not. In summary, microvessel density in bone marrow of MM is significantly increased compared to control, but was not correlated with overall survival. Further studies regarding angiogeneic molecules are needed to determine the functional role of angiogenesis in MM.

Differentiation between reinfection and recrudescence of helicobacter pylori strains using PCR-based restriction fragment length polymorphism analysis

The aim of this study was to evaluate whether PCR-based restriction fragment length polymorphism (RFLP) analysis was effective in differentiating between reinfection and recrudescence of H. pylori strains. Following a 1-2 week regimen of omeprazole 20 mg, amoxicillin 1.0 g, and clarithromycin 500 mg twice daily, twenty patients with duodenal ulcer were enrolled in the study. Ten patients (group 1, control) were not successfully treated, and another 10 patients (group 2) exhibited recurrence of infection 6-24 months following the therapy. Follow-up diagnosis was performed by Giemsa stain and CLO test. RFLP profiles of antral and midbody biopsy specimens were compared before and after therapy. PCR products using the ureC gene were digested with restriction enzymes Hha I, Mbo I, and Hind III, and the fragments generated were analyzed by agarose gel electrophoresis. Hha I, Mbo I, and Hind III digestion produced 13, 7, and 2 distinguishable digestion patterns, respectively. There was no difference in RFLP profiles seen before and after the therapy in 17 duodenal ulcer patients, while different RFLP profiles were discovered in 3 patients. Following treatment, one (group 2) patient differed in Mbo I, and two (one each from both groups) patients differed in Hha I and Mbo I RFLP patterns. Eight of group 2 patients showed recrudescence of previous infection and two patients had reinfection by another strain. This study supports the hypothesis that PCR-based RFLP analysis can be effective for differentiating reinfection and recrudescence of H. pylori strains following triple therapy.