Rapid detection of point mutations of the Neisseria gonorrhoeae gyrA gene associated with decreased susceptibilities to quinolones

Mutations in the gyrA gene resulting in amino acid changes at Ser-91 and Asp-95 are significantly associated with decreased susceptibilities to quinolones in Neisseria gonorrhoeae. To detect these mutations, we developed a rapid and simple assay based on amplification of the region of the gyrA gene containing the mutation sites by PCR and digestion of the PCR product with a restriction enzyme. A naturally occurring HinfI restriction site was present in the region containing the Ser-91 codon, and an artificial HinfI restriction site was created in the region containing the Asp-95 codon by the method of primer-specified restriction site modification. The mutations generating alterations at Ser-91 and Asp-95 were detected as restriction fragment length polymorphisms of the PCR products digested with HinfI. Fifty-five clinical strains of N. gonorrhoeae were examined for mutations in the gyrA gene by this method. Mutations at Ser-91 and/or Asp-95 were detected in all the 31 strains in which the mutations had been confirmed by DNA sequencing. Our method allows simultaneous testing of a large number of strains and provides results within 8 h. This rapid and simple assay could be a useful screening device for genetic alterations associated with decreased susceptibilities to quinolones in N. gonorrhoeae and could facilitate epidemiological studies on clinical isolates of N. gonorrhoeae with decreased susceptibilities to quinolones.

Eosinophil peroxidase deficiency in New Zealand white mice

Eosinophil peroxidase (EPO) is one of the granule enzymes in the eosinophil-specific granules and is distinct from myeloperoxidase. Here we report that peroxidase activity was absent in eosinophils of New Zealand White (NZW) mice. When NZW, New Zealand Black and their F1 mice were treated with cyclophosphamide followed by Toxocara canis infection, the kinetic changes in the number of eosinophils in peripheral blood, determined by counting in Hinkelman's diluting fluid, were almost comparable among the three strains. However, when their blood films were stained for peroxidase reaction, eosinophils of NZW mice, but not of the other strains, lacked EPO activity, though their specific granules were stained by eosin Y. Sudan black staining for phospholipid was also negative in eosinophils of NZW mice. EPO deficiency in NZW eosinophils was further confirmed by electron-microscopic observations and by measuring EPO activity in the extracts of eosinophil-rich cell suspensions. These results indicate that NZW eosinophils share most of the features with human EPO-deficient eosinophils, suggesting that the NZW mouse is a murine counterpart of human EPO deficiency.

Increased incidence of proximal colon cancer in the elderly

To define the characteristics of colorectal cancer with regard to site distribution, age, and sex, due to the significantly increased incidence of colorectal cancer in Japan, we investigated 1,205 Japanese patients with colorectal cancer between 1975 and 1994. When we compared site distribution for age and sex in the entire 20-year period, tumors in the proximal colon were more frequent in elderly patients than in young ones (p < 0.05); this tendency was true only for females (p < 0.01), but not for males. The increased incidence of proximal colon cancer in elderly patients was also found in the second 10-year period (p < 0.05). Because elderly patients are characterized by an increasingly high incidence of proximal colon cancer in recent years, more concerted efforts for the early detection of proximal colon cancer, particularly in the elderly, are called for.

Small hepatic nodules surrounding hepatocellular carcinoma

BACKGROUND/AIMS

We investigated whether or not small hepatic nodules surrounding the main hepatocellular carcinoma were malignant, while also analyzing the role of intraoperative ultrasonography in detecting these small nodules.

MATERIALS AND METHODS

Thirty-three small hepatic nodules near the main tumor in 17 patients were retrospectively studied. They were first detected either during or after the operation using intraoperative ultrasonography and/or after examining a cross-section of the resected specimen.

RESULTS

Twenty-six of the 33 small nodules were shown to be malignant when studied histologically (79%). The reliability of intraoperative ultrasonography was higher than 80 per cent for detecting nodules measuring more than 5 mm in diameter. However, it was only 25 per cent reliable with smaller nodules measuring less than or equal to 5 mm.

CONCLUSIONS

These results suggest that most small hepatic nodules with hepatocellular carcinoma should be considered to be malignant. In addition, smaller nodules measuring less than 5 mm in size can hardly be detected by intraoperative ultrasonography.

Increased expression of cytokines in liver and serum in patients with extrahepatic diseases

To determine whether the liver plays an immunological role in certain extrahepatic disorders, we investigated the expression of interleukin (IL)-1 beta, IL-6, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha in 11 patients who had recovered from cholecystolithiasis, 12 patients with gastric cancer, 20 patients with chronic hepatitis, and 6 healthy controls. Cytokine mRNAs in the liver were detected by semiquantitative reverse transcribed-polymerase chain reaction. Serum cytokines and soluble IL-2 receptor (sIL-2R) were investigated by enzyme-linked immunosorbent assays. Increases in TNF-alpha, IL-6, IL-1 beta, and IFN-gamma mRNAs were found in the livers of patients with extrahepatic diseases. TNF-alpha and IL-6 peptides were increased in the sera of patients with gastric cancer. TNF-alpha in the sera and TNF-alpha mRNA in the liver were correlated in gastric cancer patients. Surprisingly, sIL-2R in the serum of gastric cancer patients was significantly higher than the level in healthy controls. Our findings suggest that the liver produces cytokines in reaction to extrahepatic lesions. Further, the increase in sIL-2R in gastric cancer patients indicates that malignancy may affect the immune network in vivo.

Postoperative recurrence of solitary small hepatocellular carcinoma

The prognosis of hepatocellular carcinoma after hepatic resection remains poor. The major cause is postoperative recurrence, most frequently intrahepatic. During the past 7 years, we conducted a detailed study of recurrence after hepatectomy in 34 patients with solitary small hepatocellular carcinoma measuring no larger than 4 cm in diameter, in which 13 cases had postoperative recurrent tumors, and two cases were considered multicentric. Eighty-five percent of recurrences were diagnosed at 6-18 months after the operation. The cumulative recurrence rates were 61% at 5 years after operation. When analyzing the factors affecting recurrence, a significant difference was observed regarding tumor diameter. After recurrence, most patients underwent percutaneous ethanol injection treatment and/or transcatheter arterial chemoembolization and lipiodolization. Four patients died of progressive disease within 1 year after recurrence; the treatment thus seemed to have no effect. The other patients with recurrence remain alive with the disease. The overall cumulative survival rates in this series were 76% at 3 years and 60% at 5 years after operation. To obtain better results after hepatectomy, even for small hepatocellular carcinoma, careful, long-term follow-up evaluation is therefore necessary for the multidisciplinary treatment of the postoperative recurrence, as well as the early diagnosis of tumors in high-risk patients.

A life stage of particle-laden rat dendritic cells in vivo: their terminal division, active phagocytosis, and translocation from the liver to the draining lymph

Initiation of an adoptive immune response against pathogenic organisms, such as bacteria and fungi, may involve phagocytic activity of dendritic cells (DC) or their immature precursors as a prelude to antigen processing and presentation. After intravenous injection of rats with particulate matter, particle-laden cells were detected in the peripheral hepatic lymph. Since it has been known there is a constant efflux of DC from nonlymphoid organs into the draining peripheral lymph, we examined whether these particle-laden cells belonged to the DC or macrophage lineage. The majority of particle-laden cells in lymph showed immature monocyte-like cytology, and the amount of ingested particles was small relative to typical macrophages. We identified these particle-laden cells as DC based on a number of established criteria: (a) they had a phenotype characteristic of rat DC, that is, major histocompatibility complex class Ihigh+ and IIhigh+, intercellular adhesion molecule 1+ and 80% positive with the rat DC-specific mAb OX62; (b) they showed strong stimulating capacity in primary allogeneic mixed leukocyte reaction; (c) in vitro, they had little phagocytic activity; and (d) the kinetics of translocation was similar to that of lymph DC in that they migrated to the thymus-dependent area of the regional nodes. Furthermore, bromodeoxyuridine feeding studies revealed that most of the particle-laden DC were recently produced by the terminal division of precursor cells, at least 45% of them being <5.5 d old. The particle-laden DC, defined as OX62+ latex-laden cells, were first found in the sinusoidal area of the liver, in the liver perfusate, and in spleen cell suspensions, suggesting that the site of particle capture was mainly in the blood marginating pool. It is concluded that the particle-laden cells in the hepatic lymph are recently produced immature DC that manifest a temporary phagocytic activity for intravascular particles during or after the terminal division and that the phagocytic activity is downregulated at a migratory stage when they translocate from the sinusoidal area to the hepatic lymph.

Quinolone-resistant Neisseria gonorrhoeae: correlation of alterations in the GyrA subunit of DNA gyrase and the ParC subunit of topoisomerase IV with antimicrobial susceptibility profiles

Fifty-five clinical strains of Neisseria gonorrhoeae were examined for mutations in the gyrA and parC genes and for antimicrobial susceptibility profiles. The MICs of quinolones for 31 strains with alterations in GyrA were significantly higher than the MICs for 24 strains without such alterations. Eleven strains with alterations in both GyrA and ParC were significantly more resistant to fluoroquinolones than those with alterations in GyrA alone. The MICs of cephalosporins for these strains were also significantly higher than those for other strains.

Biological activities of lipopolysaccharide of Burkholderia (Pseudomonas) pseudomallei

Endotoxic activities of lipopolysaccharide (LPS) isolated from Burkholderia (Pseudomonas) pseudomallei, a causative agent of melioidosis, were investigated. Compared to an enterobacterial LPS (SAE-LPS), B. pseudomallei LPS (BP-LPS) exhibited weaker pyrogenic activity in rabbits, lethal toxicity in galactosamine-sensitized mice and murine macrophage activation, i.e. production of tumor necrosis factor, interleukin-6 and nitric oxide. BP-LPS, on the other hand, exhibited stronger mitogenic activity to murine splenocytes than SAE-LPS; moreover, it stimulated even the splenocytes of LPS-resistant C3H/HeJ mice. Unusual chemical structures in the acid-stable inner core region attached to the lipid A moiety of BP-LPS may be responsible for this strong mitogenic activity.

Hepatic inflow vessels caliber as an index for liver function

BACKGROUND/AIMS

Little is known about the serial change of the hepatic inflow vessels' caliber in the chronically diseased liver. We have analyzed the caliber change in patients with esophageal varices and examined relationship between hepatic inflow vessels diameter and age of patients who had no liver disease.

MATERIALS AND METHODS

(i) Diameters of the hepatic inflow vessels was measured on angiogram in five patients with chronic liver disease. They underwent liver angiography twice with an interval of more than 10 months. The caliber change was analyzed. (ii) Thirty-nine patients without chronic liver disease were analyzed to examine vessel diameter change with aging.

RESULTS

(i) The left hepatic artery diameter increased in size during the follow-up periods. On the other hand, the portal vein caliber increased in three cases excluding two cases whose Child grade did not change from A. (ii) The hepatic artery and the portal vein diameter had a tendency to become smaller with aging in thirty-nine patients who underwent hepatic angiography and had no liver disease.

CONCLUSIONS

Hepatic inflow vessels' caliber change, particularly increase in hepatic artery diameter, has a potential of suggesting the liver function to some extent.

Positive autoregulation of vipR expression in ViaB region-encoded Vi antigen of Salmonella typhi

vipR was the first gene in the ViaB region found to be involved in production of the Vi capsular antigen in Salmonella typhi and to be transcribed in the same direction as nine downstream genes. To investigate its function, we constructed a nonpolar vipR mutant by inserting a cat cartridge into the vipR gene on the chromosome. Inactivation of the gene decreased its transcriptional level and the levels of the downstream genes. When a functional vipR gene on a low-copy-number plasmid was introduced into the vipR mutant, the transcriptional levels of the chromosomal genes were restored. These results indicate that the vipR gene product acts as a transcriptional activator for the downstream genes. Interestingly, the vipR gene also was positively regulated by its own product. DNA-binding studies showed that protein extract that contained the VipR product specifically retarded the mobility of a 451-bp BspHI-XbaI fragment upstream of the vipR gene. In addition, complementation analysis indicated that the vipR gene was cotranscribed with a least two downstream genes, vipA and vipB. These findings suggest that the VipR product may interact with the regulatory region upstream of the vipR gene and induce operonic mRNA synthesis that includes the vipR and downstream genes.

Scanning of polypoid gallbladder lesions by ultrasonic microprobes using transpapillary catheterization

BACKGROUND AND STUDY AIMS

Polypoid lesions of the gallbladder can be diagnosed by transabdominal ultrasonography and endoscopic ultrasonography. However, the image resolution is limited, and the histopathology of these lesions is difficult to determine. We report here on our preliminary results in four patients using a high-frequency (20 MHz) ultrasonic microprobe introduced into the gallbladder via the transpapillary approach.

PATIENTS AND METHODS

Insertion of the microprobe into the gallbladder through the papilla of Vater was attempted in four patients with gallbladder diseases without preceding endoscopic sphincterotomy.

RESULTS

The lesions in the gallbladder were clearly visualized in three of the four patients. We tried to correlate the characteristic ultrasound findings with the histopathology of the lesions, which were found to be early cancer, adenoma, and adenomyomatosis on histopathology of the specimens after cholecystectomy. No complications occurred.

CONCLUSIONS

High-resolution endoscopic transpapillary ultrasonography of the gallbladder is feasible and safe, and may contribute to the diagnosis of gallbladder diseases, particularly of small polypoid lesions.

Deletion mapping on chromosome 1p in well-differentiated gastric cancer

To define the region on the short arm of chromosome 1 that is thought to include one or more tumour-suppressor genes for gastric cancers, we carried out loss of heterozygosity (LOH) studies in 26 gastric adenocarcinomas, using three restriction fragment length polymorphism (RFLP) markers and nine microsatellite markers. All tumours were informative with at least one locus; three revealed replication errors (RERs) at multiple microsatellite loci, and interstitial or telomeric allelic deletions were observed in 12 cases. Deletion mapping of these tumours defined a commonly deleted region between two loci, D1S201 and D1S197, that are 13 cM apart. As two loci within the commonly deleted region, D1S57 (pYNZ2) and D1S62 (pTHI54), were mapped respectively to 1p35 and 1p34.3 by fluorescence in situ hybridisation, we conclude that a locus likely to contain a tumour-suppressor gene for gastric cancer is located within a 13 cM region encompassing two chromosomal bands.

[Detection and identification method of three mycobacterium species and genus specific detection by polymerase chain reaction and DNA hybridization with alkaline phosphatase labeled oligonucleotide probe]

Rapid detection and identification method of mycobacteria from specimen with infected mycobacteriosis was established by the combination of polymerase chain reaction and alkaline phosphatase labeled oligonucleotide probe (PCR-ALPDH). We prepaired four kinds of probes: Mycobacterium tuberculosis complex, M. avium, M. intracellulare, and mycobacterial-probe other than tuberculosis. PCR-ALPDH was compared with conventional methods using 234 specimens which suspected mycobacteriosis. In culture, 68 specimens (29.1%) were positive and 166 specimens (70.9%) were negative. In PCR-ALPDH, 88 specimens (37.6%) were positive and 146 specimens (62.4%) were negative. In 68 specimens which were positive in culture, the agreement of results of conventional identification and PCR-ALPDH for each probes were: 39/40 (PCR-ALPDH/Culture, 97.5%) in M. tuberculosis 5/9 (55.6%) in M. avium, 6/6 (100%) in M. intracellulare and 22/28 (88.6%) in MOTT isolation. Among 166 negative culture specimens, 27 specimens were positive in PCR-ALPDH. The results indicated that PCR-ALPDH method was applicable for the establishment of rapid and sensitive mycobacterial diagnostic system.

Semantide- and chemotaxonomy-based analyses of some problematic phenotypic clusters of slowly growing mycobacteria, a cooperative study of the International Working Group on Mycobacterial Taxonomy

During previous cooperative numerical taxonomic studies of slowly growing mycobacteria, the International Working Group on Mycobacterial Taxonomy described a number of strains whose taxonomic status was ambiguous. A new study of DNA, RNA, and proteins from 66 of these organisms was performed to correlate their properties with phenotypic clustering behavior; the results of this study permitted 51 of the strains studied to be assigned to known species. The methods used to characterize the semantides included nucleotide sequencing and assessment of levels of semantide relatedness by affinity binding techniques, including whole DNA-DNA hybridization, probe hybridization, and antibody binding. There was good overall agreement between the phenotypic and chemotaxonomic clusters and the groups of organisms identified by semantide analyses. Our results supported the conclusion that we should continue to rely on polyphasic taxonomy to provide satisfactory systematic resolution of members of the genus Mycobacterium. We identified no single 16S rRNA interstrain nucleotide sequence difference value that unequivocally defined species boundaries. DNA-DNA hybridization remains the gold standard, but common resources are needed to permit DNA-DNA hybridization analyses to be made available to laboratories that are not prepared to use this technology. One of the large novel clusters which we studied corresponds to the recently described species Mycobacterium interjectum, a pathogen that resembles the nonpathogen Mycobacterium gordonae phenotypically. We also identified strains that appear to represent ribovars of Mycobacterium intracellulare which do not react with the commercial diagnostic probes that are currently used for identification of this species. Other branches or clusters consisted of too few strains to permit a decision about their taxonomic status to be made.

The thermostable direct hemolysin gene (tdh) of Vibrio hollisae is dissimilar in prevalence to and phylogenetically distant from the tdh genes of other vibrios: implications in the horizontal transfer of the tdh gene

Vibrio hollisae strains isolated recently from patients in various locations were examined for the presence of the thermostable direct hemolysin gene (tdh) using nucleic acid hybridization and polymerase chain reaction assays. The results were consistent with the previous finding that all strains of V. hollisae carry the tdh gene. In contrast, the tdh gene has been detected in a minority of strains for other Vibrio species (V. parahaemolyticus, V. cholerae non-O1, and V. mimicus). Detailed phylogenetic analysis showed that the tdh genes of the non-V. hollisae species were very closely related to each other and that the tdh gene of V. hollisae was distantly related to the tdh genes of the non-V. hollisae species. These results and the proposed insertion sequence-mediated tdh transfer mechanism suggest that the tdh gene may have been maintained stably in V. hollisae and that the tdh genes of the non-V. hollisae species may have been involved in recent horizontal transfer.

A new genetic assay for rifampicin susceptibility of Mycobacterium tuberculosis

A new method for testing rifampicin (RFP) susceptibility of Mycobacterium tuberculosis was developed. This method is based on detection of the internal sequence derived from 71-kDa heat shock protein mRNA in tubercle bacilli heat-treated in the presence of RFP. The target sequence was amplified by reverse transcription and PCR, followed by agarose gel electrophoretic analysis. No amplification occurred in one RFP-susceptible strain by exposure to 45 degrees C for 45 min in Middlebrook 7H9 broth containing RFP (10 micrograms/ml) after overnight incubation at 37 degrees C. On the other hand, an amplified 275-bp product was obtained from the RFP-resistant strain MY-129. In a subsequent trial using 65 clinical isolates, this method defined their RFP susceptibility levels as well as the verification of the MICs obtained by the conventional agar dilution method, with the exception of one RFP-susceptible strain. Thus, this method provides a rapid and practical system to determine RFP susceptibility in M. tuberculosis.

CD4+ intestinal mucosal lymphocytes in the pathogenesis of Crohn's disease

To analyze the nature of intestinal mucosal lymphocytes in Crohn's disease, we established T cell lines of patients' intraepithelial lymphocytes. T cell lines from the affected terminal ileum of the patients showed an increased proportion of CD4+V beta 5.2/5.3+ T cells. These cells were increased in number after stimulation with staphylococcal enterotoxins C1 and D, showed an increase in cytolytic activity, and produced a large amount of interferon-gamma. To clarify the role of CD4+ mucosal lymphocytes in the intestinal inflammation, we then developed a novel colitis model by immunizing a rat with trinitrobenzenesulfonic acid (TNB) emulsion with adjuvant. Deep ulceration and granuloma formation in this colitis model resembled the histopathological findings of human Crohn's disease. Immunohistochemical and flow cytometric analysis demonstrated that the number of CD45RC(high)CD4+ mucosal lymphocytes was increased. Interestingly, the administration of anti-CD4 Abs prevented severe inflammation in the model. After treatment with anti-CD4 Abs, the anti-TNB Ab titer, the number of CD45RC(high)CD4+ cells, and interferon-gamma mRNA expression were significantly decreased in the mucosa of the model. These results suggest that some subsets of CD4+ mucosal lymphocytes play an important role in the triggering and progression of inflammation in Crohn's disease.

Isolation of dendritic cells in the rat liver lymph

Lymphadenectomy of the regional lymph nodes of the rat liver resulted in the direct influx of peripheral hepatic lymph into the thoracic duct after regeneration of lymphatic vessels. Thus, we could obtain the dendritic cells in the hepatic lymph by cannulating the thoracic duct. By the double immunostaining, dendritic cells in cytosmears could be easily determined as non-B, non-T, and MHC class II-positive cells. The yield of dendritic cells after enrichment by the metrizamide density gradient was about 5 x 10(5)/first 16 hr collection/rat, with viability of more than 95% and purity of more than 70%. About 80% of dendritic cells were positive for OX62, which recognized the rat dendritic cell subpopulation. They showed strong stimulating activity in the primary allogeneic mixed leukocyte reaction. The method presented here should be applicable to studies of the roles of liver dendritic cells, especially in transplantation immunity.

[Endoscopic lithotomy using sublingual nitroglycerin]

After medical sphincter dilation using sud-lingual nitroglycerin, endoscopic removal of common bile duct stones in 15 patients was carried out. Complete stone removal was obtained in 14 of 15 patients. Only 0.3 mg to 0.6 mg nitroglycerin was needed to give an enough dilation of the orifice for cannulating the basket catheter into the bile duct. Mechanical lithotriptor was smoothly cannulated in one patient because of possible impaction. Blood pressure was dropped transiently in one patient by nitroglycerin, however, the general condition of the patient was stable. This procedure is safe, easy and effective in preserving sphincter function. Acute cholecystitis, a common complication of persistent gallbladder stone after endoscopic sphincterotomy, may be avoided by employing this method. More clinical studies, on long term and in a large scale of patients, are necessary to reduce complications that usually occur after sphincterotomy.

Transfer of Streptococcus adjacens and Streptococcus defectivus to Abiotrophia gen. nov. as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov., respectively

We performed this study to determine the 16S rRNA sequences of the type strains of Streptococcus adjacens and Streptococcus defectivus and to calculate the phylogenetic distances between these two nutritionally variant streptococci (NVS) and other members of the genus Streptococcus. S. adjacens and S. defectivus belonged to one cluster, but this cluster was not closely related to other streptococcal species. A comparative analysis of the sequences of these organisms and other low-G+C-content gram-positive bacteria revealed that the two NVS species formed a distinct cluster and were only remotely related to the Aerococcus and Carnobacterium clusters. The highest level of homology (93.7%) was found between S. adjacens and Carnobacterium divergens. Carnobacterium species have meso-diaminopimelic acid in their cell walls, but S. adjacens and S. defectivus have L-lysine as the diamino acid at position 3 in their peptidoglycan tetrapeptides. On the basis of our findings and the results of previous phenotypic studies, we propose that the NVS species should be placed in a new genus, the genus Abiotrophia, as Abiotrophia adiacens comb. nov. and Abiotrophia defectiva comb. nov.