Terson syndrome caused by ventricular hemorrhage associated with moyamoya disease--case report

A 24-year-old female presented with Terson syndrome secondary to bilateral ventricular hemorrhage as a complication of moyamoya disease. Ophthalmoscopy and magnetic resonance imaging clearly demonstrated vitreous hemorrhage in the left eye globe. Various visual symptoms are associated with moyamoya disease, almost all of which result from ischemic lesions in the visual cortex and optic pathways. In this case, the visual disturbance was caused by Terson syndrome secondary to ventricular hemorrhage. Close ophthalmological and radiological evaluation is mandatory even in patients with moyamoya disease and hemorrhagic manifestation located in the intracerebral, subarachnoid, or intraventricular space.

Functional regulation of tactile sense by brain-derived neurotrophic factor in adult rats during acute inflammation

Nerve growth factor is present in skin in limiting amounts and is known to regulate the plasticity and the sensitivity of nociceptive neurons. Recently, knock-out mouse studies showed that neurotrophin-3 and brain-derived neurotrophic factor are required for the postnatal survival and functional maturation, respectively, of tactile sensory neurons. However, the roles of neurotrophin-3 and brain-derived neurotrophic factor in adult sensory neurons have not been clarified. Here, we report an unexpected and marked acute loss of tactile sense in the rat hind paw after adjuvant-induced inflammation. This loss was shown to be closely correlated with decreases in the expression of brain-derived neurotrophic factor, and to a lesser extent of neurotrophin-3 in the inflamed skin. Administration of brain-derived neurotrophic factor, but not neurotrophin-3, after inflammation accelerated the recovery of tactile sense. These results suggested a role of brain-derived neurotrophic factor in the physiological regulation of tactile sense in adulthood.

Natural course of progression of liver fibrosis in Japanese patients with chronic liver disease type C--a study of 527 patients at one establishment

Patients with chronic hepatitis C infection show a gradual progression of fibrosis to liver cirrhosis and hepatocellular carcinoma (HCC). We studied whether the progression of liver fibrosis differed among Japanese subjects who were infected with different hepatitis C virus (HCV) genotypes. In 527 patients we examined whether there was a relationship between gender, age, history of blood transfusion, interval between date of blood transfusion and date of liver biopsy or date of diagnosis of HCC, serum alanine aminotransferase level, platelet count or HCV genotype, with the extent of liver fibrosis, classified into four stages (F1-F4). Moreover, we compared the mean rate of liver fibrosis progression per year in patients with each HCV genotype. Patients who had a higher fibrosis score tended to be older, have a lower platelet count and a longer interval since blood transfusion than those who had a lower fibrosis score. The mean rate of liver fibrosis progression was 0.12 +/- 0.15 stages per year after the blood transfusion. However, the progression rate of liver fibrosis in patients who had received a blood transfusion when they were > or = 30 years of age was 0.19 +/- 0.22, while the progression rate of liver fibrosis in the patients who had received a blood transfusion when they were < 30 years was 0.09 +/- 0.09. In conclusion, chronic hepatitis C is a progressive disease, and patients with genotype 1b, 2a and 2b have a similar rate of progression of liver fibrosis. Particular attention should be paid to patients who are infected with HCV when > or = 30 years of age, because intrahepatic fibrosis rapidly progresses in these patients.

A prospective study of interferon therapy modified by pre-treatment viral load in cirrhotic patients. Tokyo-Chiba Hepatitis Research Group

BACKGROUND/AIMS

The relative role of hepatitis C virus (HCV) load and subtype as predictors of the efficacy of interferon therapy has been clarified in patients with chronic hepatitis C, but the effectiveness of interferon therapy in cirrhotic patients is still unclear.

METHODS

To resolve this issue, we undertook a multicenter, randomized, and prospective study of 114 cirrhotic patients with hepatitis C virus infection. The patients were selected to undergo two different periods (6 or 12 months) of IFN therapy according to viral load. Patients with "low" viral load (< or = 10(5.8) copies/ml serum) were randomly divided into three groups, receiving 6 or 9 million units (MU) interferon three times a week for 6 months (total dose: 468 or 702 MU), or of a modified regimen using 6MU of IFN over 6 months (total dose 564 MU), while patients with "high" viral load (< or = 10(6.3) copies/ml serum) were also randomly divided into two groups of 6 or 9 MU of IFN three times a week for 12 months (total dose: 936 or 1,404 MU).

RESULTS

HCV-RNA negativity rate at the completion of treatment with 6 or 9 MU IFN was 65% in patients with "low" viral load, in contrast to 14% in patients with "high" viral load. Sustained virological response was found in 40% of patients with "low" viral load irrespective of the three different regimens, in contrast to only 1 out of 35 patients (3%) with "high" viral load. Viral eradication was found in approximately 50% of patients having a low virus load (< or = 10(4.3) copies/ml) and with HCV subtype 2a. Univariate and multivariate analysis revealed that pretreatment viral load was a significant factor contributing to efficacy of IFN therapy.

CONCLUSIONS

Sustained response was scarcely achieved in cirrhotic patients with high viral loads even after a 12-month course of intensive IFN therapy. This result indicates that there is a certain cut-off level of HCV RNA load which can not be eradicated.

A new SHV-derived extended-spectrum beta-lactamase (SHV-24) that hydrolyzes ceftazidime through a single-amino-acid substitution (D179G) in the -loop

A new SHV-derived extended-spectrum beta-lactamase (SHV-24) conferring high-level resistance to ceftazidime but not cefotaxime and cefazolin was identified in Japan. This enzyme was encoded by a transferable 150-kb plasmid from an Escherichia coli clinical isolate. The pI and K(m) for CAZ of this enzyme were 7.5 and 30 microM, respectively. SHV-24 was found to have a D179G substitution in the Omega-loop of the enzyme.

High prevalence of TT virus DNA in human saliva and semen

Using the PCR assay, we found a high prevalence of TT virus (TTV) DNA in saliva and semen from patients who were seropositive for TTV. This finding suggests that the presence of TTV in body fluids other than serum may affect the routes of viral transmission.

Retrospective diagnosis of diphtheria by detection of the Corynebacterium diphtheriae tox gene in a formaldehyde-fixed throat swab using PCR and sequencing analysis

The tox gene of Corynebacterium diphtheriae was detected in a formaldehyde-fixed throat swab taken from a 68-year-old man who was reported to have died of suffocation due to a pharyngeal tumor. DNA templates prepared from bacterial cells fixed with 10% formaldehyde were subjected to a PCR analysis with tox gene-specific PCR primers. The resultant 112-nucleotide-long PCR product was sequenced using a dye terminator method, and an expected 57-nucleotide-long internal sequence of the tox gene was detected. This method is applicable for retrospective diagnosis in diphtheria cases in which only a formaldehyde-fixed clinical sample is available.

Molecular structure of bacterial endotoxin (Escherichia coli Re lipopolysaccharide): implications for formation of a novel heterogeneous lattice structure

Analyses of crystals of Escherichia coli Re lipopolysaccharide (LPS) formed after storage in 1% triethylamine indicate that the LPS molecules are assembled to form a monolayered structure consisting of a novel heterogeneous lattice structure, the greater part of which is occupied by one kind of lattice (lattice I), corresponding to the acyl chain portion of lipid A, and the remainder is occupied by the other kind of lattice (lattice II), corresponding to the 3-deoxy-Dmanno-octulosonic acid (dOclA) dimer and the N-acetylglucosamine disaccharide of lipid A. X-ray diffraction reveals that the type of cell is monoclinic (a = 5.53 A, b = 27.2 A, c = 6.47 A, alpha = 90 degrees, beta = 125.8 degrees, gamma = 90 degrees ). Atomic force microscopy shows that crystals consist of multiple layers; the thickness of a layer corresponds to the b-axis value, and two types of surface topographies are visualized. One, regarded as the view onto the acyl chain ends, is two-dimensional arrays of oval bodies that constitute the lattice, with the lattice constants corresponding to the a- and c-axes and the angle of beta (lattice I). The other, regarded as the view onto the dOclA dimers, is two-dimensional arrays of dromedary-back-like bodies that constitute the lattice with axes of 9.0 and 10.7 A and the angle of 65 degrees formed by both axes (lattice II). Based on these results, we present the molecular model of E. coli Re LPS.

Alterations of the INK4a/ARF locus in human intracranial germ cell tumors

Little is known about the molecular mechanisms responsible for the development of intracranial germ cell tumors (ICGTs). Recently, we demonstrated that the balance of the p53-mdm2 interactions is disrupted in ICGTs. The p14ARF product, a tumor suppresser gene located on the INK4a/ARF locus, acts as one of the major factors affecting p53-mdm2 interactions via its binding to mdm2 and the stimulation of mdm2 degradation. To evaluate whether genetic alterations of the INK4a/ARF locus occur in the genesis of ICGTs, we analyzed the INK4a/ARF genes in 21 ICGTs-10 pure germinomas and 11 nongerminomatous germ cell tumors. Fifteen (71%) of the 21 ICGTs displayed genetic alterations, including 14 homozygous deletions and 1 frameshift mutation. Furthermore, the frequency of the alterations was higher in pure germinomas [9 (90%) of the 10] than in nongerminomatous germ cell tumors [6 (55%) of the 11; P = 0.09]. These data suggested that INK4a/ARF gene abnormalities could play an important role in the genesis of ICGTs, especially in pure germinoma.

Histologic improvement of fibrosis in patients with hepatitis C who have sustained response to interferon therapy

BACKGROUND

Short-term histologic improvement in hepatitis C-related hepatic fibrosis has been noted in studies with more than 2 years of follow-up, but the long-term effects of interferon therapy on hepatic fibrosis remain unclear.

OBJECTIVE

To assess changes in hepatic fibrosis after interferon therapy in patients with chronic hepatitis C.

DESIGN

Retrospective cohort study.

SETTING

7 university hospitals and 1 national hospital in Japan.

PATIENTS

593 patients with chronic hepatitis C who underwent a paired liver biopsy from 1987 to 1997. Of these, 487 patients received interferon therapy and 106 patients were untreated.

INTERVENTION

Patients in the treatment group received a 2- to 6-month course of interferon within 6 months after the initial biopsy.

MEASUREMENTS

Fibrosis and inflammatory activity in paired biopsy samples obtained a median of 3.7 years apart (range, 1 to 10 years) were graded by using the criteria of Desmet and colleagues (F0 to F4) and those of the French METAVIR Cooperative Study Group (A0 to A3), respectively. Changes in fibrosis staging and activity scores and yearly rates of fibrosis progression and regression were calculated.

RESULTS

183 of the 487 interferon-treated patients showed a sustained virologic response. Activity grade was unchanged in most of the untreated patients and improved in 89% (CI, 83% to 93%) of patients with a sustained virologic response. A sustained response to interferon was associated with a mean (+/-SE) reduction in fibrosis score of -0.60+/-0.07 at less than 3 years of follow-up and -0.88+/-0.08 at 3 years or more of follow-up. The rate of fibrosis progression was -0.28+/-0.03 unit/y (regression) in patients with sustained response, 0.02+/-0.02 unit/y in patients with nonsustained response (P< 0.001), and 0.10+/-0.02 unit/y in untreated patients.

CONCLUSION

Although the time between biopsies partly affected the patient's clinical course, the differences observed here suggest that in patients with chronic hepatitis C, regression of fibrosis is associated with sustained virologic response to interferon therapy.

Gastric epithelial cell proliferation and apoptosis in Helicobacter pylori-infected mice

BACKGROUND

Helicobacter pylori causes gastritis and is strongly associated with gastroduodenal ulcer and gastric cancer. The bacterium is associated with an increased rate of epithelial proliferation, which can be reversed by eradication of the organism. The mechanism of this response is not known, but this epithelial proliferation is one of the risk factors for developing gastric carcinoma. Recently, apoptosis also was found to be increased in the gastric mucosa of persons carrying H. pylori.

METHODS

cagA-positive H. pylori isolated from a human gastric ulcer was inoculated into BALB/C mice. At 4, 6, 12, 18 and 24 weeks, mice were injected with bromodeoxyuridine 5 mg/kg and killed 1 h later. Proliferation was analysed by histochemical staining for BrdU; apoptosis was examined by the TUNEL assay.

RESULTS

The number of BrdU-labelled cells in the antrum was significantly increased by H. pylori infection beginning 12 weeks after infection. The number of apoptotic cells in this tissue was increased significantly by 6 weeks after inoculation.

CONCLUSION

The proliferation observed in H. pylori infection may be a response to increased apoptosis.

Simultaneous detection of hepatitis B, C, and G viral genomes by multiplex PCR method

We established a multiplex polymerase chain reaction (PCR) method for simultaneous detection of hepatitis B, C, and G viral genomes. The levels of concordance with the data obtained by conventional single PCR method were 100% for single infection, 98 to 100% for double infections, and 92% for triple infections. This method is not only suited to rapid, large-scale epidemiological screening and clinical diagnosis of those virus infections occurring alone or in combination, but is also time- and cost-effective.

[The use of a modified vertical mandibular osteotomy for exposure of a distal cervical internal carotid artery]

We report herein the case of a 56-year-old woman who presented with repeated transient ischemic attacks (TIAs). Cerebral angiography revealed that the left redundant internal carotid artery (ICA) uncharacteristically curved medially. These findings were highly suggestive of an internal carotid artery aneurysm at the level between the first and second cervical vertebral bodies. The lesion was presumed to be difficult to access by the surgical procedure usually adopted in carotid endarterectomy. Thus, we decided to employ a modified vertical mandibular osteotomy. The operative view revealed that the lesion was atherosclerotic stenosis with ulceration, so carotid endarterectomy was indicated. This mandibular osteotomy not only provided us with wide, satisfactory exposure of the distal cervical internal carotid artery but also afforded good mandibular stability during the postoperative period.

Histologic improvement of fibrosis in patients with hepatitis C who have sustained response to interferon therapy

BACKGROUND

Short-term histologic improvement in hepatitis C-related hepatic fibrosis has been noted in studies with more than 2 years of follow-up, but the long-term effects of interferon therapy on hepatic fibrosis remain unclear.

OBJECTIVE

To assess changes in hepatic fibrosis after interferon therapy in patients with chronic hepatitis C.

DESIGN

Retrospective cohort study.

SETTING

7 university hospitals and 1 national hospital in Japan.

PATIENTS

593 patients with chronic hepatitis C who underwent a paired liver biopsy from 1987 to 1997. Of these, 487 patients received interferon therapy and 106 patients were untreated.

INTERVENTION

Patients in the treatment group received a 2- to 6-month course of interferon within 6 months after the initial biopsy.

MEASUREMENTS

Fibrosis and inflammatory activity in paired biopsy samples obtained a median of 3.7 years apart (range, 1 to 10 years) were graded by using the criteria of Desmet and colleagues (F0 to F4) and those of the French METAVIR Cooperative Study Group (A0 to A3), respectively. Changes in fibrosis staging and activity scores and yearly rates of fibrosis progression and regression were calculated.

RESULTS

183 of the 487 interferon-treated patients showed a sustained virologic response. Activity grade was unchanged in most of the untreated patients and improved in 89% (CI, 83% to 93%) of patients with a sustained virologic response. A sustained response to interferon was associated with a mean (+/-SE) reduction in fibrosis score of -0.60+/-0.07 at less than 3 years of follow-up and -0.88+/-0.08 at 3 years or more of follow-up. The rate of fibrosis progression was -0.28+/-0.03 unit/y (regression) in patients with sustained response, 0.02+/-0.02 unit/y in patients with nonsustained response (P< 0.001), and 0.10+/-0.02 unit/y in untreated patients.

CONCLUSION

Although the time between biopsies partly affected the patient's clinical course, the differences observed here suggest that in patients with chronic hepatitis C, regression of fibrosis is associated with sustained virologic response to interferon therapy.

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.