Inhibition of adjuvant-induced inflammatory hyperalgesia in rats by local injection of neurotrophin-3

The induction of nerve growth factor (NGF) in inflammatory tissue has been shown to be involved in hyperalgesia. In the present study, the role of neurotrophin-3 (NT-3) in the regulation of inflammatory hyperalgesia was analyzed. Inflammatory hyperalgesia was induced by intraplantar injection of complete Freund's adjuvant (CFA) to the rat hind paw. NT-3 levels in the plantar skin were much higher than NGF levels (1.24 and 0.14 ng/g tissue, respectively) before CFA injection, but decreased significantly 6 h to 48 h after the injection while NGF was markedly induced at 6 h but decreased thereafter. When 1 microg of NT-3 was locally injected at 5 h after CFA injection at the time NT-3 levels decreased, hyperalgesia was reversed transiently but specifically. These results suggest an inhibitory role of NT-3 in the regulation of pain sensitivity.

Altered vascular response to acetylcholine in conditions of endothelial damage in the isolated perfused rat stomach

To examine the mechanism of stress ulcers and the relation between endothelium derived relaxing factor (EDRF)/NO and gastric mucosal blood flow (GMBF), we used an isolated perfused rat stomach model and studied the effects of an autonomic nerve activator, nitric oxide synthase (NOS) synthesis, and an EDRF/NO inhibitor on gastric blood circulation. Rats were divided into four groups according to pretreatment: (1) control; (2) those given gossypol, a drug provoking endothelial cell damage; (3) those given L-N monomethylarginine (L-NMMA), a specific inhibitor of EDRF/NO; and (4) those subjected to water-immersion stress. Using this model we collected the perfusion fluid from the portal vein at various time points. After administration of acetylcholine, the perfusion flow increased in the control group, but perfusion flow showed no change in the L-NMMA group. On the other hand, the perfusion flow decreased in the gossypol and water-immersion stress groups. The perfusion fluid from the control group contained cGMP, but this substance was absent in the perfusion fluid of the other experimental groups. We considered that increased cGMP in the fluid came from endothelial cells. We presume that the presence of EDRF/NO is essential for the control of GMBF and that from the viewpoint of gastric ulcers, the lack of EDRF/NO may be an important factor in the decrease of GMBF in the early stages of water-immersion stress.

A preliminary survey of extended-spectrum beta-lactamases (ESBLs) in clinical isolates of Klebsiella pneumoniae and Escherichia coli in Japan

We conducted a survey of extended-spectrum beta-lactamases (ESBLs) among 16805 Escherichia coli and 9794 Klebsiella pneumoniae clinical isolates recovered from 196 separate medical institutions during the period January 1997 to January 1998. Using the criteria for minimal inhibitory concentrations (MICs) of oxyimino-cephalosporins of >/=8 microg ml(-1) and confirmation by double-disk test, we detected 15 E. coli and 34 K. pneumoniae isolates producing ESBLs. Genotypes of ESBLs determined by PCR with type-specific primers included one TEM-derived and 24 SHV-derived ESBLs, in addition to 24 Toho-1-type ESBLs, one of the major types of ESBLs reported in Japan. Nucleotide sequence analysis of SHV-specific PCR products revealed that SHV-12 was the dominant type of SHV-derived ESBL. In addition, we also identified TEM-26 and SHV-2. This is the first report characterizing TEM- and SHV-derived ESBLs in Japan.

Telomerase activity of needle-biopsied liver samples: its usefulness for diagnosis and judgement of efficacy of treatment of small hepatocellular carcinoma

BACKGROUND/AIMS

High values for telomerase activity in malignant tumors have been reported. The clinical usefulness of measurements of telomerase activity as a diagnostic tool and to evaluate treatment efficacy in small hepatocellular carcinoma was investigated.

METHODS

We investigated 22 patients (26 nodules) with intrahepatic abnormal nodules < or =20 mm in size determined by abdominal ultrasound. All underwent needle biopsies of tumorous nodules and extranodular regions of the liver by ultrasound guidance for histopathological diagnosis and measurement of telomerase activity by the fluorescence-based telomeric repeat amplification protocol. Re-biopsy of the same nodule was performed 1 week after percutaneous ethanol injection therapy to measure telomerase activity in 10 patients (10 nodules) found to have hepatocellular carcinoma. Liver-biopsied samples from 30 patients with chronic hepatitis C were used as a control.

RESULTS

Telomerase activity increased with statistical significance stepwise: chronic hepatitis (n=30, mean: 0.00 U) extranodular regions (pre-cirrhosis or cirrhosis, n=22, mean: 1.80 U), atypical hyperplasia (borderline or premalignant lesions, n= 15, mean: 7.02 U) and low-grade malignant hepatocellular carcinoma (n=11, mean: 31.96 U) (p<0.0001 by the Kruskal-Wallis test). Percutaneous ethanol injection therapy resulted in loss (0.00 U) of telomerase activity in 9 nodules and persistence in 1 nodule.

CONCLUSIONS

Measurement of telomerase activity appeared useful for diagnosis of intrahepatic abnormal nodules and assessment of the efficacy of percutaneous ethanol injection therapy and may be used as an alternative diagnostic method, especially when pathohistological discrimination between atypical hyperplasia and well-differentiated hepatocellular carcinoma is difficult.

Hepatitis C virus core protein interacts with 14-3-3 protein and activates the kinase Raf-1

Persistent hepatitis C virus (HCV) infection is a major cause of chronic liver dysfunction in humans and is epidemiologically closely associated with the development of human hepatocellular carcinoma. Among HCV components, core protein has been reported to be implicated in cell growth regulation both in vitro and in vivo, although mechanisms explaining those effects are still unclear. In the present study, we identified that members of the 14-3-3 protein family associate with HCV core protein. 14-3-3 protein bound to HCV core protein in a phosphoserine-dependent manner. Introduction of HCV core protein caused a substantial increase in Raf-1 kinase activity in HepG2 cells and in a yeast genetic assay. Furthermore, the HCV core-14-3-3 interaction was essential for Raf-1 kinase activation by HCV core protein. These results suggest that HCV core protein may represent a novel type of Raf-1 kinase-activating protein through its interaction with 14-3-3 protein and may contribute to hepatocyte growth regulation.

[A SHV-derived extended-spectrum beta-lactamase (SHV-12) produced by an Escherichia coli recovered from wound abscess in post operative case with rectal carcinoma]

A 62-year-old woman admitted for rectal carcinoma suffered from a post-operative bacterial infection. Oxy-imino-beta-lactams including cefotiam (CTM) and cefozopran (CZOP) were prescribed for this case, but the patient developed a wound abscess followed by peritonitis. She recovered from the bacterial infection after drainage and recurrent washing of the abscess. An ephemeral aggravation of infectious signs was observed just after creation of an artificial anus, and CZOP was again administered, and no evident bacterial infection occurred. The patient recovered, then was followed as an outpatient to date. A CAZ-resistant (MIC, > 16 micrograms/ml) E. coli was recovered from pus of her wound abscess. Since the CAZ-resistance decreased (MIC, 64 micrograms/ml-->0.13 microgram/ml) by the presence of clavulanate (CVA) in this isolate, this strain was speculated to be an extended spectrum beta-lactamase (ESBL) producer at an early stage of infection. A similar strain was also isolated from the feces. Therefore, we immediately took measures to block the nosocomial spread of this microorganism, and we succeeded in preventing a nosocomial outbreak of this strain. It was later confirmed by PCR analysis and DNA sequencing analysis that this CAZ-resistant E. coli strain produces an ESBL (SHV-5-2a = SHV-12). This is the first report of a case of infection with SHV-derived ESBL producing E. coli strain in Japan. We are concerned that further dissemination of this kind of microorganism might occur in the near future also in Japan, as it has been widely observed in European countries and the US. We believe that it will be very important to distinguish the type of beta-lactamases for rigorous bacterial infection control with the prudent use of antibiotics. In other words, we in Japan must recall that various gram-negative bacterial species that produce TEM-, SHV-derived ESBLs, Toho-1, AmpC, or IMP-1 are already widespread. Thus, we should take this fact into consideration when we do antibiotic susceptibility tentings and interpretation of the results for promotion of accurate chemotherapy.

Pentagalloylglucose, an antisecretory component of Paeoniae radix, inhibits gastric H+, K(+)-ATPase

We purified a compound with strong inhibitory effect on H+, K(+)-ATPase from Paeoniae radix, which has been used in Japan for the treatment of gastritis and peptic ulcers. The compound was identified as 1,2,3,4,6,-penta-o-galloyl-beta-D-glucose by proton nuclear magnetic resonance, carbon-13 nuclear magnetic resonance, and fast atomic bombardment mass spectrometry. The IC50 of the compound for H+, K(+)-ATPase was 166 nmol/l. Kinetic analyses indicated that the inhibition of the enzyme by pentagalloylglucose was noncompetitive with respect to K+. Pentagalloylglucose had relatively weak inhibitory effects for Mg(+)-ATPase (IC50: > 10 mumol/l) and Na+, K(+)-ATPase (IC50: 2.7 mumol/l). Pentagalloylglucose also inhibited the accumulation of [14C]aminopyrine in parietal cells that had been isolated from guinea pig stomach and stimulated by 10 mumol/l histamine (IC50: 7.8 mumol/l) and 1 mmol/l dbc-AMP (IC50: 10 mumol/l). These results suggest that pentagalloylglucose is a potent inhibitor of H+, K(+)-ATPase and may be responsible for inhibition of acid secretion by Paeoniae radix.

Trends in antimicrobial-drug resistance in Japan

Multidrug resistance in gram-positive bacteria has become common worldwide. In Japan until recently, gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Serratia marcescens were controlled by carbapenems, fluoroquinolones, and aminoglycosides. However, several of these microorganisms have recently developed resistance against many antimicrobial drugs.

Convenient test for screening metallo-beta-lactamase-producing gram-negative bacteria by using thiol compounds

A simple disk diffusion test was constructed for detection of IMP-1-type metallo-beta-lactamase-producing gram-negative bacteria. Two Kirby-Bauer disks containing ceftazidime (CAZ) and a filter disk containing a metallo-beta-lactamase inhibitor were used in this test. Several IMP-1 inhibitors such as thiol compounds including 2-mercaptopropionic acid, heavy metal salts, and EDTA were evaluated for this test. Two CAZ disks were placed on a Mueller-Hinton agar plate on which a bacterial suspension was spread according to the method recommended by the National Committee for Clinical Laboratory Standards. The distance between the disks was kept to about 4 to 5 cm, and a filter disk containing a metallo-beta-lactamase inhibitor was placed near one of the CAZ disks within a center-to-center distance of 1.0 to 2.5 cm. For IMP-1-producing strains, the growth-inhibitory zone between the two disks expanded, while no evident change in the shape of the growth-inhibitory zone was observed for CAZ-resistant strains producing serine beta-lactamases such as AmpC or SHV-12. As a result, 2 to 3 microliter of undiluted 2-mercaptopropionic acid or mercaptoacetic acid able to block IMP-1 activity gave the most reproducible and clearest results, and CAZ-resistant strains producing AmpC or extended-spectrum beta-lactamases were distinguishable from IMP-1 producers by this test. A similar observation was made with IMP-1-producing clinical isolates such as Serratia marcescens, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas putida, Acinetobacter spp., and Alcaligenes xylosoxidans. The specificity and sensitivity of this test were comparable to those of PCR analysis using bla(IMP)-specific primers. Therefore, this convenient test would be valuable for daily use in clinical laboratories.

[Epidemiology of drug-resistance and clinical microbiologists in the 21st century]

Many efficacious antimicrobial agents have been developed in the latter half of the 20th century, and this has enabled us to overcome bacterial infections. However, various drug-resistant bacteria including MRSA and VRE have been emerging and these strains will cause serious life-threatening medical problems in the 21st century. Since development of new antimicrobial agents currently stagnates++, promoting the appropriate and prudent use of antimicrobial agents based on EBM is strongly recommended. Thus, establishment of a surveillance system of drug-resistant bacterial infections and their epidemiology as well as further activities by clinical technologists as specialists in medical microbiology will be indispensable in the next century.

[Gene examination methods (detection and genotyping of resistant genes)--metallo-beta-lactamase]

Metallo-beta-lactamases have a hydrolysing activity against various beta-lactams including carbapenems, and beta-lactamase inhibitors such as clavulanic acid and sulbactum. Infections caused by metallo-beta-lactamase producing gram-negative bacteria are becoming a serious problem in Japanese clinical settings despite the recent progress in medical technology. Current screening methods can not distinguish metallo-beta-lactamase producers from those producing AmpC beta-lactamase. Here we show a convenient method of detecting metallo-beta-lactamase producers using a thiol compound(2-mercaptopropionic acid) as well as a PCR method with metallo-beta-lactamase gene specific primers.

[Gene examination methods (detection and genotyping of resistant genes)--multiple-drug-resistant Pseudomonas aeruginosa]

Pseudomonas aeruginosa has been regarded as one of the most stubborn pathogens that easily acquire resistance to various antimicrobial agents. Recently, several clinical isolates that have acquired multiple-resistance to carbapenems, fluoroquinolones, and newly developed aminoglycosides such as amikacin have been reported. Thus, the "drug-resistant P. aeruginosa" was designated as a "class 4 pathogen" in the new "Law Concerning the Prevention of Infectious Diseases and Medical Care for Patients with Infections" in Japan. It is generally considered that no medical facility can escape from severe attack by both multiple-drug resistant gram-positive cocci such as MRSA and gram-negative rods including P. aeruginosa in the 21st century. Therefore, emergency countermeasures should be anticipated to prevent further proliferation of these multiple-drug resistant pathogens.

Biochemical and virological response to interferon therapy in patients with chronic hepatitis C, co-infected with hepatitis G virus

It is still unclear whether hepatitis G virus (HGV) and hepatitis C virus (HCV) co-infection influences the natural course of chronic HCV infection and the response to interferon (IFN) therapy. In this study, we investigated the HGV RNA changes and responses to IFN therapy of HGV RNA-positive hepatitis C patients. The presence of HGV RNA in 264 patients who received IFN therapy at our institute was examined using the nested reverse transcription-polymerase chain reaction with primers deduced from the 5' non-coding region (5'-NCR) of the HGV. We also analysed the nucleotide sequences of the 5'-NCR and HGV before and after IFN therapy. Twelve (4.5%) of the 264 patients with chronic hepatitis C were HGV RNA positive. Of these 12 patients, full information was available in nine. Of those nine, seven became HGV RNA negative during IFN therapy but in six of the seven a relapse occurred. HCV RNA was not detected 1 year after IFN therapy in six patients. The serum alanine aminotransferase (ALT) levels of all the HCV RNA-negative patients post-treatment was within the normal range, irrespective of their HGV RNA status. Nucleotide sequences did not change after IFN therapy in any patient. Hence, we confirm that HGV is sensitive to IFN therapy but the liver damage caused by HGV infection is very mild or does not modify the liver function tests.

Comparison of nerve growth factor mRNA expression in cardiac and skeletal muscle in streptozotocin-induced diabetic mice

To address the role of nerve growth factor (NGF) in diabetes mellitus (DM)-induced cardiac autonomic neuropathy, we quantitated and compared the expression of NGF mRNA in the cardiac and the skeletal muscle in experimental DM mice with the RT-PCR-HPLC method, which we have developed previously, using a NGF deletion mutant RNA as an internal standard. DM was induced in ICR mice via intraperitoneal injection of streptozotocin. RT-PCR was performed using total RNA extracted from left ventricle and soleus muscle, and the levels of NGF mRNA were quantitated by HPLC analysis. NGF mRNA content of the cardiac muscle was 17-fold higher than the skeletal muscles in control mice. NGF mRNA content of the cardiac muscle in diabetic mice at 6 weeks was 4.0-fold higher than that in the control mice, while that of the skeletal muscle in diabetic mice was not different from the controls. These results indicated that the DM-induced increase in NGF mRNA content was higher in cardiac muscle than skeletal muscle, and that NGF might play an important role in cardiac autonomic neuropathy.

Prediction of the development of hepato-cellular-carcinoma in patients with liver cirrhosis by the serial determinations of serum alpha-L-fucosidase activity

OBJECTIVE

Evaluation of the usefulness of the serial determinations of serum alpha-L-fucosidase (AFU) activity for prediction of the development of hepatocellular carcinoma (HCC) was performed.

METHODS AND PATIENTS

Serum AFU activity was determined monthly for 42 months in 73 patients with liver cirrhosis (LC).

RESULTS

HCC was diagnosed in 27 patients by means of ultrasonography during this observation period. In 23 (85%) of the 27 patients, serum AFU activity was found to exceed 700 nmole/ml/h during the LC stage. HCC developed within a few years in 23 (82%) of 28 LC patients with AFU activity exceeding 700 nmole/ml/h, in contrast, it developed in only 4 (9%) of 45 LC patients with AFU activity below 700 nmole/ml/h. AFU activity was already elevated in 23 (85%) of 27 patients at least 6 months before the detection of HCC by ultrasonography.

CONCLUSION

It is conceivable that the development of HCC can be predicted by means of serial determinations of serum AFU activity in patients with LC.

Enhanced theophylline metabolism in patients with bronchial asthma at age 4 and under

The plasma levels of theophylline (TP) and its metabolites were measured in patients with bronchial asthma who were treated with a slow-release preparation of TP. The ratios of the plasma levels of these metabolites to TP levels in the group aged 1-4 years were larger than those in the group aged 5 years and older, suggesting enhanced activity of drug-metabolizing enzymes during infancy.

Crystallization of lipopolysaccharide from a Salmonella typhimurium semi-rough (SR) mutant

Salmonella typhimurium SR-form lipopolysaccharide (LPS), consisting of a single repeating unit of the O-antigenic polysaccharide, linked to the R-core consisting of oligosaccharide that is, in turn, linked to lipid A, formed crystals whose shapes were hexagonal plates, discoids, and solid columns when precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and kept in 70% ethanol containing 250 mm MgCl2 at 4 C for 10 days. Among these crystals, the basic form is considered to be the hexagonal plates. Analyses of hexagonal plate crystals showed that they consist of hexagonal lattices with a lattice constant (a axis) of 4.62 A and longitudinal axis (c axis) of approximately 100 A. In X-ray diffraction patterns in the low-angle region, crystals of S. typhimurium SR-form LPS exhibited much less distinct reflections when compared with crystals of synthetic Escherichia coli-type lipid A. In contrast to the previous finding that S. minnesota S-form LPS possessing the O-antigenic polysaccharide does not crystallize under the same experimental conditions as used in the present study, the presence of a single repeating unit of the O-antigenic polysaccharide does not inhibit crystallization.

Role of multiple efflux pumps in Escherichia coli in indole expulsion

Escherichia coli chromosome encodes several multidrug transporters. Despite their protective function against antibacterial agents, the specific physiological actions of these transporters are not fully understood. E. coli produces indole, a metabolite of tryptophan, under physiological conditions. Defined inactivation of the acrEF gene, the product of which is known as an energy-dependent multiple drug efflux pump, decreased indole excretion while reintroduction of the acrEF gene restored it. A DeltaacrEF mutant accumulated more intracellular indole than the parent. This mutant was more susceptible to the growth-inhibitory effect of indole than the parent. These results indicate that the AcrEF system plays a significant role in indole efflux.