D-alanine:D-alanine ligase: phosphonate and phosphinate intermediates with wild type and the Y216F mutant

The crystallographic structure of the D-alanine:D-alanine ligase of the ddlB gene of Escherichia coli complexed with a D-Ala-D-alpha-hydroxybutyrate phosphonate and the structure of the Y216F mutant ligase complexed with a D-Ala-D-Ala phosphinate have been determined to 2.2 and 1.9 A resolution, respectively, and refined to R factors of 0.156 and 0.158. In each complex the inhibitor has reacted with ATP to produce ADP and a tight-binding phosphorylated transition state intermediate. Comparison of these two structures with the known crystal structure of the phosphinate intermediate of the wild-type ligase shows no major conformational changes, but B factors indicate differences in mobility of loops covering the binding site. The weaker inhibition of the Y216F mutant by both inhibitors is thought to be due in part to the loss of an interloop hydrogen bond. A similar mechanism may account for poor inhibition of VanA, the homologous D-Ala:D-lactate ligase produced by vancomycin-resistant enterococci.

Expression of transforming growth factor-beta and type IV collagen in early streptozotocin-induced diabetes

The earliest manifestations of type I diabetic nephropathy include mesangial matrix expansion, basement membrane thickening, and renal hypertrophy. Transforming growth factor (TGF)-beta, a potent inducer of matrix protein synthesis, is a prime candidate to mediate the glomerular changes observed in diabetes. However, the temporal expression of TGF-beta and matrix proteins during the early stage of diabetic nephropathy has not been clearly defined. Using in situ hybridization and immunohistochemistry, we determined the expression of TGF-beta and type IV collagen mRNAs and proteins in glomeruli and interstitium of diabetic rats 3, 7, and 14 days after streptozotocin (STZ) administration. There was a marked increase in the expression of TGF-beta and alpha1(IV) procollagen mRNAs in glomerular and tubulointerstitial cells as early as 3 days after induction of diabetes, an effect that persisted for 14 days. A concomitant increase in TGF-beta and type IV collagen proteins was also observed at each time point. Insulin treatment substantially inhibited the increased expression of TGF-beta and collagen type IV mRNAs and proteins. We conclude that TGF-beta is increased in glomeruli during the early phase of rapid renal growth in diabetes. These findings suggest that TGF-beta may be a key factor involved in the pathogenesis of basement membrane thickening and extracellular matrix accumulation. Inhibition of TGF-beta and type IV collagen expression by insulin treatment suggests that they may be useful structural markers for determining the efficacy of therapeutic intervention during early diabetic nephropathy.

Nitinol self-expanding stents: when severe twisting occurs, self-expansion may ensue after a waiting period

One of the major disadvantages of nitinol endocoil stents is said to be incomplete deployment leading to twisting and stent dysfunction. We report a patient with irresectable pancreatic head cancer where severe twisting of the nitinol stent occurred which resolved on the day after stent insertion; the stent took its normal shape ten days later, whereafter the patient lived without stent-related problems for one year until his death. This shows that prospective management rather than immediate stent extraction may be warranted in such cases of stent dysfunction.

Bilateral patent ductus arteriosus and nonconfluent pulmonary arteries in neonates as shown by radial artery angiography

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Role of rebamipide on induction of heat-shock proteins and protection against reactive oxygen metabolite-mediated cell damage in cultured gastric mucosal cells

Reactive oxygen metabolites (ROM) have been reported to be important in the pathogenesis of ischemia/ reperfusion-, ethanol-, nonsteroidal antiinflammatory drug-, or Helicobacter pylori-induced gastric mucosal injury. Rebamipide, a novel antiulcer agent, has been reported either to prevent various acute experimental gastric mucosal lesions or to accelerate the healing of chronic gastric ulcers. The underlying mechanism by which rebamipide exerts its cytoprotective effect in the damaged stomach is not fully determined. We investigated the role of rebamipide in protecting against ROM-mediated cell damage in gastric mucosal cells and in inducing cytoprotective proteins. Cells were exposed to ROM enzymatically generated by hypoxanthine-xanthine oxidase. Cytotoxicity was quantified by measuring specific 51Cr release from prelabeled cells. ROM caused dose-dependent increase in cytotoxicity and amount of thiobarbituric acid-reactive substances (TBA-RS). ROM-induced cytotoxicity and TBA-RS were dose-dependently decreased by the addition of rebamipide and/or catalase, but not by superoxide dismutase alone. The effects of rebamipide on electric spin resonance signal were investigated. We found that the DMPO spin adduct ESR signal of hydroxyl radicals (DMPO-OH) was significantly attenuated by rebamipide. Western blot analysis showed that induction of heat-shock protein (HSP70) was significantly increased following rebamipide administration in a dose-dependent manner. Based on these results, it is concluded that rebamipide exerted a protective effect on HX-XO-induced gastric mucosal cell cytotoxicity through one or more of the following mechanism(s): (1) inhibition of lipid peroxidation of the cell membrane; (2) hydroxyl radical scavenging activity; and (3) induction of cellular cytoprotective protein such as HSP70.

Peritoneoscopic liver biopsy findings in asymptomatic chronic HBsAg carriers with normal liver function tests and no hepatomegaly

Asymptomatic chronic HBsAg carriers with normal liver function tests are, in general regarded as having no liver pathology. Most of the histologic findings in asymptomatic chronic carriers have been reported from areas with low incidence of Hepatitis B virus (HBV) infection, such as North America and Western Europe. It is well known that there are many differences in HBV infection between low and high endemic areas, but there have been few reports on the histologic findings of asymptomatic chronic HBsAg carriers from endemic areas. The present study was undertaken in Korea which is one of the endemic areas for HBV infection and was designed to assess the prevalence of chronic liver disease by peritoneoscopic liver biopsy among asymptomatic chronic HBsAg carriers and to make a basis for the follow-up of asymptomatic chronic HBsAg carriers according to the results obtained. One hundred and ten asymptomatic HBsAg-positive carriers with normal liver function tests and no hepatomegaly were included in the study. Final diagnosis by peritoneoscopic liver biopsy revealed that of the 110 asymptomatic carriers only 27 (24.5%) had a histologically normal liver, while 51 (46.4%) had chronic liver diseases, and the remaining 32 (29.1%) had nonspecific histologic abnormalities (nonspecific reactive changes in 18 cases, cholestasis in 6 cases, and fatty change in 8 cases). Of the 51 patients with chronic liver diseases, 3 had liver cirrhosis, 4 chronic active hepatitis with cirrhosis, 11 chronic active hepatitis and 33 chronic persistent hepatitis. The frequency of liver cirrhosis and chronic active hepatitis with cirrhosis was significantly high in the over 30 years of age group (12.1%) than in the under 30 years of age group (0%; p = 0.011 by Fisher's exact test). In conclusion, 46.4% of the Korean asymptomatic chronic HBsAg carriers with normal liver function tests and no hepatomegaly had chronic liver disease. This finding contrasted with reports from low incidence areas of HBV infection. Our results suggest that in endemic areas, a liver biopsy should be considered to assess the status of liver disease in asymptomatic chronic HBsAg carriers even if liver function tests are normal and hepatomegaly is absent, and the result can be used as a basis for the follow-up of each asymptomatic chronic HBsAg carriers.

Gain of D-alanyl-D-lactate or D-lactyl-D-alanine synthetase activities in three active-site mutants of the Escherichia coli D-alanyl-D-alanine ligase B

Escherichia coli D-Ala-D-Ala ligase (Ddl) and the vancomycin resistance-conferring protein VanA are homologues, but VanA has gained the ability to activate D-lactate (D-Lac) and make the depsipeptide D-Ala-D-Lac as well as D-Ala-D-Ala. This depsipeptide ligase activity of VanA is its crucial catalytic function necessary for phenotypic vancomycin resistance. We report here that three E. coli DdlB active-site mutants that we made previously based on X-ray structure/function predictions have gained interesting new ligase activities. Y216, S150, and E15 form a hydrogen-bonding triad that orients an omega-loop to close over the active site and also to orient substrate D-Ala1. Mutants Y216F and S150A have gained depsipeptide (D-Ala-D-Lac, D-Ala-D-hydroxybutyrate) ligase activity with dipeptide/depsipeptide partition ratios that mimic the pH behavior of VanA. E15Q has negligible depsipeptide synthetase activity but now uniquely activates D-Lac as the electrophilic rather than the nucleophilic partner for condensation with D-Ala to make a regioisomeric D-Lac-D-Ala, an amide rather than an ester product. These results provide insights into the active-site architecture of the ligases and the subsites for recognition of D-Ala VS D-Lac and predict the Y216F substitution will impart D-Ala-D-Lac synthetase activity to Ddls from Grampositive bacteria with intrinsic resistance to vancomycin.

Characterization of the mononickel metallocenter in H134A mutant urease

A mutant form of Klebsiella aerogenes urease possessing Ala instead of His at position 134 (H134A) is inactive and binds approximately half the normal complement of nickel (Park, I.-S., and Hausinger, R. P.(1993) Protein Sci. 2, 1034-1041). The crystal structure of the H134A protein was obtained at 2.0-A resolution, and it confirms that only Ni-1 of the two nickel ions found in the native enzyme is present. In contrast to the pseudotetrahedral geometry observed for Ni-1 in native urease (where it is liganded by His-246, His-272, one oxygen atom of carbamylated Lys-217, and a water molecule at partial occupancy), the mononickel metallocenter in the H134A protein was found to possess octahedral geometry and was coordinated by the above protein ligands plus three water molecules. The nickel site of H134A urease was probed by UV-visible, variable temperature magnetic circular dichroism, and x-ray absorption spectroscopies. The spectroscopic data are consistent with the presence of Ni(II) in octahedral geometry coordinated by two histidylimidazoles and additional oxygen and/or nitrogen donors. These data underscore the requirement of Ni-2 for formation of active urease and demonstrate the important role of Ni-2 in establishing the proper Ni-1 coordination geometry.

Evaluation of therapeutic regimens for the treatment of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is currently considered the most important exogenous factor in the genesis of gastritis and peptic ulcer disease. However, the optimum regimen for the eradication of H. pylori remains unclear. The purpose of this study was to evaluate the eradication rate of H. pylori, the side effects, and the patients' compliance with regard to various drug regimens. We also analyzed factors influencing the eradication of H. pylori. One hundred and eighty patients were included and divided into four groups: 42 patients (Group I) received tripotassium dicitrato bismuthate (240 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; 55 patients (Group 2) received omeprazole (20 mg b.i.d.) and amoxicillin (1000 mg b.i.d.) for 14 days; 36 patients (Group 3) were treated with omeprazole (20 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; and 47 patients (Group 4) received omeprazole (20 mg q.d.) and amoxicillin (500 mg t.i.d.) for 14 days and then tripotassium dicitrato bismuthate (240 mg b.i.d.) and nizatidine (150 mg q.d.) for 14 days. The diagnosis of H. pylori was made by histology. The eradication of H. pylori was defined both by histology (H&E and Giemsa stain) and by rapid urease test (CLOR) showing negative for H. pylori 4 weeks after the completion of therapy. Of the 180 patients, 95 patients had non-ulcer dyspepsia, 40 patients had gastric ulcer and 45 patients had duodenal ulcer. The eradication rate of H. pylori was highest (89.3%) in Group 3, as compared with Group 1 (68.9%), Group 2 (65.4%), and Group 4 (48.9%). The eradication rate was significantly higher in Group 3 than in Groups 2 and 4 (p < 0.05). There was no significant difference in the eradication rate among clinical diagnosis, sex and age. But, in the conventional triple therapy (Group 1), the eradication rate was higher in male (78.6%) than in female (46.2%). The side effects in order, were nausea (22.1%), dizziness (19.5%), abdominal pain (11.6%) and diarrhea (97%), and there was no difference among the drug regimens. The compliance of the patients was good (more than 80% irrespective of drug regimen). On the basis of these findings, the side effects of the drugs seemed minimal, and the compliance of patients was good irrespective of the drug regimen. In conclusion, the triple therapy with omeprazole, metronidazole and amoxicillin was the most effective regimen and could be recommended for H. pylori eradication.

The functional relationships between hiatal hernia and reflux esophagitis

The purpose of this research was to investigate functional studies by which the hiatal hernia (HH) may be relevant to a reflux esophagitis (RE). Group I consisted of healthy controls who were endoscopically normal (n = 21). Group II consisted of patients with hiatal hernia but no reflux esophagitis (n = 8). Group III had patients with hiatal hernia with reflux esophagitis (n = 9). Group IV had patients with reflux esophagitis but no hiatal hernia (n = 16). Esophageal manometry, ambulatory 24 hour intraesophageal pH monitoring, acid clearance test, and gastric emptying scan were performed in each of the patients. The contraction amplitude at 3 cm above the lower esophageal sphincter did not differ significantly among the four groups, but the mean lower esophageal sphincter pressure was significantly decreased in group II. The DeMeester score in ambulatory 24 hour intraesophageal pH monitoring was significantly higher in group III compared with the controls. No significant difference among the groups was found with respect to acid clearance. Total and proximal gastric emptying times (T1/2) were significantly delayed in group III. We found that hiatal hernia combined with delayed gastric emptying may bear a relationship to the multifactorial origins of reflux esophagitis, and we suggest a rationale for using prokinetic agents as the therapeutic regimen in patients with HH complicated by RE.

Metal ion interaction with urease and UreD-urease apoproteins

Klebsiella aerogenes urease in a Ni-containing enzyme (two Ni per alpha beta gamma unit) that is purified as an apoprotein from cells grown in Ni-free medium. Partial activation of urease and UreD-urease apoproteins is achieved in vitro by incubation in the presence of Ni(II) and CO2, whereas incubation of these proteins with Ni alone leads to the formation of inactive species [Park, I.-S., & Hausinger, R. P. (1995) Science 267, 1156-1158]. Here we determined the kinetics of these inhibitory reactions and demonstrated the presence of two Ni ions per alpha beta gamma unit in the inactive proteins. Although metal-substituted urease has never been purified from Ni-deprived cell, several other metal ions were shown to bind to the urease apoproteins. Divalent Zn, C, Co, and Mn all inhibited Ni- and Co2-promoted urease activation at concentrations below that of Ni, whereas Mg and Ca ions did not inhibit this process. Ni-inhibited species recovered their ability to be partially activated after EDTA treatment. In contrast, samples that were exposed to Co or Cu ions were irreversibly inactivated, and EDTA treatment of Zn- or Mn-inhibited samples led to reduced levels of activation competence. Mn-substituted urease, generated from urease apoprotein samples in a Mn- and Co2-dependent manner, was shown to be active, whereas other metal-substituted forms if urease lacked activity. The Mn-protein possessed only 2% of the activity of Ni-activated apoprotein [ approximately 8.0 vs approximately 400 mumol min-1 (mg protein)-1], but its KM value was only moderately altered from that of the native enzyme (3.86 +/- 0.15 mM vs 0.2 mM). Unlike the Ni-containing enzyme, Mn-urease was inhibited by EDTA. Given the evidence that urease apoprotein binds numerous metal ions, we speculate on possible roles for the UreD, UreF, and UreG accessory proteins in urease activation.

Comparison of antiproliferative effects of 1-histamine-2 receptor antagonists, cimetidine, ranitidine, and famotidine, in gastric cancer cells

In the immune system, histamine is known to suppress cytotoxic T-lymphocytes and nitrogen induced lymphocyte thymidine uptake, down-regulate some cytokines, and activate suppressor T-lymphocytes, and in the gastrointestinal system, histamine was reported to have trophic effects on gastrointestinal epithelial cells. Enhanced rates of cell proliferation by histamine are implicated in the pathogenesis. This study was designed since there is a lack of comparative data about the cell proliferations of histamine-2 receptor antagonist (H2-RA), cimetidine, ranitidine, and famotidine, in gastric cancer. KATO-III and AGS cell lines were used in this experiment. The concentrations of the histamine and cimetidine were 10(-5)-10(-8) M, respectively and those of ranitidine and famotidine were 10(-6)-10(-9)M, respectively. Cell proliferation after drug treatment was evaluated by direct cell counting, [3H]thymidine incorporation, and MTT assay. Activities of ornithine decarboxylase (ODC), a rate limiting enzyme in polyamine synthesis, were measured after each drug treatment. Protein kinase A, a cAMP-dependent protein kinase system, was assayed using [alpha-32P]ATP. Histamine showed statistically significant cell proliferating effects in a dose-dependent manner (P < 0.001), the maximal effect in 10(-5) M concentration. ODC activities were increased in accordance with the increment of cell numbers after histamine treatment. Cimetidine reversed the histamine-stimulated cell proliferation significantly, the maximal effect in 10(-5) M concentration (P < 0.01). Although ranitidine showed the tendency to attenuate the cell proliferation dose-dependently, but without statistical significance, famotidine did not show such an effect at all. cAMP-dependent protein kinase activities were significantly increased following 10(-5) M histamine treatment, also reversed significantly by cimetidine co-administration (P < 0.01). Beneficial clinical outcomes could be anticipated from cimetidine treatment in patients with gastric cancer by anti-proliferating effects against gastric cancer cells. These effects of H2-RA are likely to be mediated by specific interactions at the H2-receptor.

Extrahepatic bile duct hepatocellular carcinoma without primary hepatic parenchymal lesions--a case report

Obstructive jaundice is rarely a presenting symptom of hepatocellular carcinoma (HCC). Most of the cases in the literature describing obstructive jaundice by HCC have a major hepatic component. Extrahepatic HCCs without primary hepatic parenchymal lesions are extremely rare. We encountered a case of extrahepatic HCC without primary hepatic parenchymal lesions in a 36-year-old man who presented with jaundice. We extensively sought primary hepatic parenchymal lesions preparatively and postoperatively with hepatic angiography and combined computed tomography (CT) studies, such as CT arterioportography and lipiodol-CT. The patient has been followed up for 1 year without definite evidence of recurrence. We herein report an unusual manifestation of HCC.

Anorectal dysfunction in systemic sclerosis

This study was aimed to evaluate the anorectal dysfunction in systemic sclerosis (SSc) and propose the clinical significance of anorectal manometry in patients with SSc. Seven patients with SSc were evaluated with manometry for anorectal function and an additional 11 normal subjects were collected as a control group. The study group underwent esophageal manometry as well and the correlation between the degree of anorectal and esophageal dysfunction was evaluated. Patients showed a lower tolerance for balloon distention of the rectum than controls (minimal sensory volume and urgency volume, P < 0.05). The resting and squeezing pressure of the anal sphincter and the functional length of the anal canal showed no significant difference in these two groups. Rectoanal inhibitory reflex was absent in one (14%) and diminished in two (29%) of seven patients with SSc. SSc patients also showed abnormal esophageal manometry findings, notably decreased LES pressure and body amplitude of distal 2/3 esophagus. The comparison between manometric profiles of anorectum and esophagus showed no significant correlation by statistical analysis. In conclusion, our data could suggest that anorectal function may be impaired in patients with SSc which could reflect the involvement of the anorectum by the disease, and that anorectal manometric studies can be useful to detect such dysfunction in patients with SSc, even before clinical symptoms.

A case of flutamide-induced acute cholestatic hepatitis--a case report

Flutamide, an oral nonsteroidal, antiandrogenic, anilid compound which inhibits the uptake and binding of androgens to nuclear receptors in the prostate, is used with or without LH-RH analogues for treatment of patients with metastatic carcinoma of the prostate. Clinically significant hepatotoxicities such as toxic hepatitis, cholestatic hepatitis, hepatic failure, and even death have rarely been reported in the English literature, but no case has been reported in Korea. A 75-year-old man with metastatic carcinoma of the prostate had taken flutamide (750 mg/day) for 7 months and suddenly developed jaundice and general weakness. The findings of blood chemistries were compatible with cholestatic hepatitis, but ultrasonography, viral marker and auto-antibody studies did not reveal any attributable causes. Histologic examination of a sono-guided liver biopsy only disclosed centrilobular cholestasis, nuclear glycogenosis and mild sinusoidal lymphocytic infiltration. Discontinuation of flutamide resulted in an almost full recovery of the patient's liver function in 2 months. We, herein, report a case of flutamide-induced acute choestatic hepatitis with a brief review of the literature.

Metal ion interaction with urease and UreD-urease apoproteins

Klebsiella aerogenes urease in a Ni-containing enzyme (two Ni per alpha beta gamma unit) that is purified as an apoprotein from cells grown in Ni-free medium. Partial activation of urease and UreD-urease apoproteins is achieved in vitro by incubation in the presence of Ni(II) and CO2, whereas incubation of these proteins with Ni alone leads to the formation of inactive species [Park, I.-S., & Hausinger, R. P. (1995) Science 267, 1156-1158]. Here we determined the kinetics of these inhibitory reactions and demonstrated the presence of two Ni ions per alpha beta gamma unit in the inactive proteins. Although metal-substituted urease has never been purified from Ni-deprived cell, several other metal ions were shown to bind to the urease apoproteins. Divalent Zn, C, Co, and Mn all inhibited Ni- and Co2-promoted urease activation at concentrations below that of Ni, whereas Mg and Ca ions did not inhibit this process. Ni-inhibited species recovered their ability to be partially activated after EDTA treatment. In contrast, samples that were exposed to Co or Cu ions were irreversibly inactivated, and EDTA treatment of Zn- or Mn-inhibited samples led to reduced levels of activation competence. Mn-substituted urease, generated from urease apoprotein samples in a Mn- and Co2-dependent manner, was shown to be active, whereas other metal-substituted forms if urease lacked activity. The Mn-protein possessed only 2% of the activity of Ni-activated apoprotein [ approximately 8.0 vs approximately 400 mumol min-1 (mg protein)-1], but its KM value was only moderately altered from that of the native enzyme (3.86 +/- 0.15 mM vs 0.2 mM). Unlike the Ni-containing enzyme, Mn-urease was inhibited by EDTA. Given the evidence that urease apoprotein binds numerous metal ions, we speculate on possible roles for the UreD, UreF, and UreG accessory proteins in urease activation.

Spontaneous bowel perforation during the course of acute pancreatitis--a case report

We recently experienced a case of spontaneous perforation of infected necrosis into the colon and duodenum during the course of acute pancreatitis in a 63 year-old male patient. Enteric perforations or fistulas in the setting of acute pancreatitis implicate severe underlying pathology and have substantial morbidity and mortality. In the meantime it has generally been accepted that infected pancreatic or peripancreatic necrosis should be managed surgically as soon as possible. Enteric perforations in the present case contributed to transient improvement of the patient's infection sign and condition, and thus an early operation was able to be avoided. Delayed surgical management resulted in complete recovery of the patient without postoperative morbidity. Herein we report an unusual complication of acute pancreatitis.

p53 protein expression in extrahepatic bile duct cancer

p53 mutations, a tumor suppressor gene located on chromosome 17p, are the most common genetic alterations found in human cancers. Although the p53 expression or mutation has been investigated in a variety of cancers there have been very few studies in extrahepatic bile duct cancers. In this study, we investigated the immunohistochemical expression of p53 in formalin fixed paraffin embedded archival specimens of 36 extrahepatic bile duct cancers in which p53 expression was found in eighteen (50%) cases. There was no significant difference in age, gender, size of tumor, histologic grade, extent of tumor involvement, lymph node metastasis and tumor resectability according to p53 immunoreactivity. Comparison of survival duration according to p53 expression showed no significant difference. In conclusion, we reported 50 percent of p53 expression in extrahepatic bile duct cancers by immunohistochemical staining and we found no prognostic significance of p53 expression in dinicopathologic parameters.

A case of paraesophageal hernia repaired by laparoscopic approach

Paraesophageal hernia comprises only 2 approximately 5% of all hiatal hernias but is prone to incarceration and strangulation. For this reason they must be recognized and repaired as expeditiously as possible. The laparoscopic approach has already been successfully applied to the repair of the more common sliding hiatal hernia and it seems reasonable to propose that the paraesophageal hernia, provided it is not complicated, might also be repaired by the laparoscopic technique. We present here a case of paraesophageal hernia which has been successfully repaired by the laparoscopic approach. A 73-year-old female suffering from postprandial fullness in the retrosternal area was diagnosed preoperatively with paraesophageal hiatal hernia with gastroesophageal acid reflux and was submitted for laparoscopic repair. The procedure entailed reduction of the hernia, mobilization of the esophagogastric junction with crural repair and partial fundoplication. At the 9th-month follow-up, the patient had remained asymptomatic and follow-up studies revealed no evidence of hernia or acid reflux. As a result of this favorable experience with minimal morbidity, early hospital discharge, and effective control of symptoms without adverse sequalae, laparoscopic repair can be considered as the curative and minimal invasive method in the management of paraesophageal hernia.

Characterization and regulation of the latent transforming growth factor-beta complex secreted by vascular pericytes

Transforming growth factor-beta (TGF-beta) stimulates the accumulation of extracellular matrix in renal and hepatic disease. Kidney glomerular mesangial cells (GMC) and liver fat-storing cells (FSC) produce latent of inactive TGF-beta. In this study, we characterized the latent TGF-beta complexes secreted by these cells. Human FSC produce a single latent TGF-beta complex, predominantly of the TGF-beta 1 isoform, whereas GMC secrete multiple complexes of latent TGF-beta, containing beta 1 and beta 2 isoforms. At least four forms were identified in GMC using ion exchange chromatography, including a peak not previously described in other cell types which eluted at 0.12 M NaCl, and predominantly of the beta 2 isoform. Both cell types secrete the latent TGF-beta 1 binding protein of 190 kDa, as part of a high molecular weight TGF-beta complex. Epidermal growth factor stimulates the secretion of latent TGF-beta and latent TGF-beta binding protein in both cell types. Secretion of latent TGF-beta in both cell types was found to be associated with secretion of decorin. This study shows that vascular pericytes from the kidney and the liver have distinctly different profiles of latent TGF-beta complexes, with GMC secreting a unique form of latent TGF-beta 2. The regulatory effect of epidermal growth factor and platelet-derived growth factor has potential implication for the pathophysiology of liver regeneration and chronic liver and kidney diseases.

Bacterial resistance to vancomycin: five genes and one missing hydrogen bond tell the story

A plasmid-borne transposon encodes enzymes and regulator proteins that confer resistance of enterococcal bacteria to the antibiotic vancomycin. Purification and characterization of individual proteins encoded by this operon has helped to elucidate the molecular basis of vancomycin resistance. This new understanding provides opportunities for intervention to reverse resistance.

Serum neopterin levels in ovarian tumors

OBJECTIVES

The aims of this study were to evaluate the difference between benign and malignant ovarian tumors through measurement of preoperative serum neopterin and CA 125 levels and to evaluate the correlation between serum neopterin levels and prognosis.

METHODS

Preoperative serum neopterin levels were measured in 55 ovarian tumors. Of these, 29 malignant tumors were studied over a 3-year follow-up period.

RESULTS

Statistical analysis demonstrated significant differences in neopterin levels between those with benign or malignant ovarian tumors, and different survival rates between the 11 patients whose preoperative neopterin levels were > or = 7.9 nM/l and the 18 patients whose preoperative neopterin levels were < 7.9 nM/l (P < 0.01). The sensitivity of preoperative serum neopterin levels (> or = 7.9 nM/l) in detecting malignant ovarian tumors was 37.9%, the specificity was 96.1%, the positive predictive value 72.0%, the negative predictive value 63.3% and the diagnostic efficiency 65.4%, and those of preoperative serum CA 125 levels (> or = 35 U/ml) in detecting malignant ovarian tumors were 62.1%, 73.1%, 91.7%, 58.1% and 85.5%, respectively.

CONCLUSIONS

Measurement of preoperative serum neopterin levels helped to discriminate between benign and malignant ovarian tumors and was related to ovarian cancer survival. In particular the combination of CA 125 and neopterin measurements showed a better sensitivity for the diagnosis of ovarian cancer than neopterin alone.

Dysphagia due to mediastinal tuberculous lymphadenitis presenting as an esophageal submucosal tumor: a case report

Mediastinal tuberculous lymphadenitis is rare in adults, and it is even rarer for dysphagia to be the presenting symptom of mediastinal tuberculous lymphadenitis. Mediastinal tuberculous lymphadenitis with esophageal symptoms has been presented as esophageal ulceration, mucosal or submucosal mass with ulceration, fistula or sinus formation, extrinsic compression, or displacement of the esophagus. An exaggerated form of extrinsic compression may be presented as a submucosal tumor, radiologically or endoscopically. A barium esophagography of a 34 year-old woman with painful dysphagia revealed a large submucosal tumor-like mass on the mid-esophagus. The symptom was spontaneously improved over a 3-week period together with reduction of the mass size. A computed tomography of the chest disclosed an enlarged subcarinal lymph node and histologic examination of the specimen obtained by thoracoscopic biopsy brought about a diagnosis of tuberculosis. We herein report a case of mediastinal tuberculosis with unusual manifestations.

Similar metabolites formed from beta-carotene by human gastric mucosal homogenates, lipoxygenase, or linoleic acid hydroperoxide

To determine the basis for the formation of excentric cleavage products of beta-carotene (beta-C) after incubation with human gastric mucosal homogenates, we have studied the effect of lipoxygenase in beta-C metabolism. beta-C was incubated with human gastric mucosal homogenates, soybean lipoxygenase with linoleic acid, or the lipoxygenase primary product, 13(S)-hydroperoxycis,trans-9,11-octadecadienoic acid (13-LOOH). The beta-C metabolites, beta-apo-14', -12', -10', and -8'-carotenals, beta-apo-13-carotenone, retinoic acid, and retinal were detected and quantified by HPLC after a 30-min incubation with 1.8 microM beta-C. The products from the lipoxygenase plus linoleic acid incubation and from the lipoxygenase primary product, 13-LOOH, with beta-C were exactly the same as the products from a human gastric mucosal homogenate incubation. Significantly larger amounts of the same beta-C metabolites were formed when beta-C was incubated with gastric mucosal homogenates and lipoxygenase together. Furthermore, nordihydroguaiaretic acid (NDGA), a specific lipoxygenase inhibitor, was found to significantly inhibit the formation of beta-apo-carotenoids and retinoids produced by gastric mucosal homogenates incubated with beta-C. The similarity of the beta-C metabolites when beta-C was incubated with human gastric mucosal homogenate, lipoxygenase plus linoleic acid, or 13-LOOH and the inhibition of beta-C metabolite production by NDGA in gastric tissue incubation with beta-C suggest that lipoxygenase is involved in beta-C metabolism in gastric mucosa. The activity of 13-LOOH in our hands would indicate that an enzyme-linked process is occurring in gastric tissue producing fatty acid hydroperoxides, and that the hydroperoxide, or a radical species derived from it, is able to carry out the oxidation of beta-C independently of the enzyme.

Adjuvant effect of polyadenylic.polyuridylic acid on antibody production of recombinant hepatitis B surface antigen in mice

The adjuvant effect of polyadenylic.polyuridylic acid [poly(A).poly(U)] on antibody production against recombinant hepatitis B surface antigen (rHBsAg) was investigated. Immunization of adult Balb/c mice with rHBsAg plus poly(A).poly(U) elicited significantly higher antibody responses than immunization of mice immunized with rHBsAg alone. Such an adjuvant effect was evident even in mice sensitized with subimmunogenic doses of the antigen.