Differential growth characteristics and streptomycin susceptibility of virulent and avirulent Mycobacterium tuberculosis strains in a novel fibroblast-mycobacterium microcolony assay

The ability to spread from cell to cell may be an important virulence determinant of Mycobacterium tuberculosis. An in vitro assay was developed to characterize this ability among four strains of M. tuberculosis: the attenuated strain H37Ra, the virulent strains H37Rv and Erdman, and a virulent clinical isolate (Stew). Confluent monolayers of human skin fibroblasts were infected with these strains and overlaid with agar-medium. M. tuberculosis infection developed over 21 days as microcolonies originating within the plane of the fibroblasts. Microcolonies of the virulent strains had an elongated appearance and exhibited extensive cording. The cords appeared to invade adjacent cells within the plane of the monolayer. Microcolony diameter of the Erdman strain was significantly larger than that of the other virulent strains, indicating that virulent strains can have distinguishing phenotypes in this assay. In contrast, avirulent H37Ra microcolonies were rounded and noncorded. H37Ra microcolonies were significantly smaller than those of the virulent strains. Microcolony diameter of the virulent strains was not reduced by the extracellularly acting antibiotic streptomycin at concentrations of up to 5.0 microgram/ml. In contrast, H37Ra microcolony size was reduced at concentrations as low as 0.5 microgram/ml. Growth of all strains was similarly inhibited by 1.0 microgram of streptomycin per ml in fibroblast-conditioned tissue culture medium alone. When fibroblasts were infected with the M. tuberculosis strains without an agar overlay, with and without streptomycin, numbers of CFU mirrored the changes observed in the microcolony assay. There was a statistically significant decrease in H37Ra CFU compared to virulent strains after treatment with streptomycin. These differences between H37Ra and virulent strains in human fibroblasts suggest that H37Ra may be lacking a virulence determinant involved in cell-to-cell spread of M. tuberculosis.

Membrane-bound and extracellular beta-lactamase production with developmental regulation in Streptomyces griseus NRRL B-2682

A new type of beta-lactamase has been isolated and characterized in Streptomyces griseus NRRL B-2682. The enzyme has membrane-bound and extracellular forms. Biochemical characterization of some of the properties of the enzyme showed that it belongs to the class A group of penicillinases. Comparison of the membrane-bound and extracellular forms of the beta-lactamases suggests that they seem to be differently processed forms of the same enzyme. The N-terminal amino acid sequence of the extracellular form of the beta-lactamase showed a high degree of similarity to a D-aminopeptidase of another Streptomyces griseus strain. Secretion of the beta-lactamase was affected by the differentiation state of the strain since in spontaneous non-sporulating mutants only the membrane-bound form was present. In accordance with this when sporulation of the wild-type strain was inhibited it failed to secrete extracellular beta-lactamase. Addition of globomycin to the non-sporulating cells liberated the enzyme from the membrane, indicating that the protein is processed normally by signal peptidase II and a glyceride-thioether group, together with a fatty acid amide-linkage, is responsible for the attachment of the enzyme to the cellular membrane. Under sporulation-repressed conditions addition of peptidoglycan fragments and analogues or inhibition of cell wall biosynthesis by penicillin-G induced beta-lactamase secretion and also restored sporulation both in solid and submerged cultures. These results confirm that beta-lactamase secretion is tightly coupled to the sporulation process in S. griseus.

Histopathological investigation of gingival tissue from patients with rapidly progressive periodontitis

In this study, fine structural features of the pocket walls in rapidly progressive periodontitis (RPP) and adult periodontitis (AP) in 20 cases were compared using light and transmission electron microscopy. Gingiva was also obtained from a control group of periodontally healthy teeth. Clinical parameters were assessed in both RPP and AP patients and in controls. Bone destruction and attachment loss were more marked in RPP than in AP. Light microscopical observations of inflamed RPP tissue as compared to AP showed gross histological distortions in the pocket walls. Micro-ridges within the epithelium and large intercellular spaces between the epithelial cells were observed in most RPP biopsies. Epithelial cells surrounding the microclefts and adjacent keratinocytes were found to produce interleukin-1beta (IL-1beta). Prevotella intermedia and Porphyromonas gingivalis were identified in the RPP biopsies using immunohistological methods. These microorganisms were localized outside the epithelium and inside intercellular spaces. Furthermore, the effect of inflammation on the distribution of collagen types I, III, IV, V, and VI in the human gingiva was studied after staining them with antibodies to these proteins. In RPP and AP tissues, the staining was sparse in areas of inflammation and leukocytic infiltration. Collagen type I and III were almost entirely lost at sites of inflammation. Type V and VI collagen antibodies were retained in inflamed areas. Type IV collagen was restricted to basement membrane structures. These observations demonstrated numerous structural features indicative of more pronounced degenerative changes in RPP than in AP.

Cell-density sensing: come on inside and tell us about it

The developmental pathway chosen by a Bacillus subtilis cell is influenced by the local cell density. To sense cell density, the cell monitors at least three different secreted signal peptides, two of which are detected by a new type of transduction mechanism involving their specific transport into the cell.

Cloning and characterization of the gene for amylosucrase from Neisseria polysaccharea: production of a linear alpha-1,4-glucan

The gene for the amylosucrase from Neisseria polysaccharea (ATCC 43768) was cloned by use of a functional expression system in Escherichia coli XL1-Blue. The deduced amino acid sequence of the protein has homology to the sequences of the alpha-amylase class of enzymes, with the highest similarities being found to the sequences of the trehalose synthase from Pimelobacter sp. strain R48 (17) and amylomaltase from Thermotoga maritima (11). However, the regions of highest homology within the alpha-amylase class of enzymes, which are essential for the catalytic activity, are only scarcely found in the sequence of amylosucrase. By using the enzyme isolated from culture supernatants of transformed E. coli cells, it is possible to synthesize linear alpha-1,4-glucans from sucrose, indicating that the enzyme is not capable of producing alpha-1,6-glycosidic linkages on its own.

A 140-kilodalton extracellular protein is essential for the accumulation of Staphylococcus epidermidis strains on surfaces

Two distinct pathogenic mechanisms, adhesion to polymer surfaces and subsequent accumulation of sessile bacterial cells, are considered important pathogenic steps in foreign body infections caused by Staphylococcus epidermidis. By using mitomycin mutagenesis, we have recently generated a mutant, strain M7, from S. epidermidis RP62A which is unaffected in adhesion but deficient in accumulation on glass or polystyrene surfaces and lacks a 115-kDa extracellular protein (designated the 140-kDa antigen; F. Schumacher-Perdreau, C. Heilmann, G. Peters, F. Götz, and G. Pulverer, FEMS Microbiol. Lett. 117:71-78, 1994). To evaluate the role of this protein in accumulation, we harvested extracellular proteins from S. epidermidis RP62A grown on dialysis membranes placed over chemically defined medium, purified the protein by using ion-exchange chromatography, determined its N-terminal amino acid sequence, and raised antiserum in rabbits. The antibody recognized only a single band in a Western immunoblot of the crude extracellular extract. With the microtiter biofilm test, antiserum at a dilution of < or =1:1,000 blocked accumulation of RP62A up to 98% whereas preimmune serum did not. The 140-kDa antigen was found only in extracellular products from bacteria grown under sessile conditions. Of 58 coagulase-negative clinical isolates, 32 strains were 140-kDa antigen positive and produced significantly larger amounts of biofilm than the 26 strains that were 140-kDa antigen negative. The 140-kDa protein appears to be biochemically and functionally unrelated to any previously described factors associated with biofilm formation. Thus, the 140-kDa antigen, referred to as accumulation-associated protein, may be a factor essential in S. epidermidis accumulation and, due to its immunogenicity, may allow the development of novel immunotherapeutic strategies for prevention of foreign body infection.

Expression of aerobactin genes by Shigella flexneri during extracellular and intracellular growth

The expression of the Shigella flexneri chromosomal aerobactin genes during growth of the bacterium within tissue culture cells was assayed. During intracellular growth, aerobactin promoter activity was repressed relative to the level observed in bacteria grown extracellularly, even when the bacteria had been starved for iron prior to infection. Similarly, the level of one of the proteins encoded by this operon, the aerobactin outer membrane receptor, Iut, was reduced in the intracellular environment. These studies indicate that the aerobactin system is not highly expressed by bacteria within host cells, suggesting that siderophore-independent iron acquisition systems can provide essential iron during intracellular multiplication.

Purification and partial characterization of a novel human platelet aggregation factor in the extracellular products of Streptococcus mitis, strain Nm-65

A human blood platelet aggregation factor was purified from the extracellular products (ECP) of Streptococcus mitis, strain Nm-65 by sequential chromatography on DEAE-Sepharose CL-6B, hydroxyapatite and Superdex 75 columns. The purified factor (S. mitis-derived human platelet aggregation factor, Sm-hPAF) gave a single band with a molecular weight of 66 kDa on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). Sm-hPAF showed a peak absorption at 278 nm and an isoelectric point of around 8.5. Chemical analyses revealed that Sm-hPAF contained no sugars and that its first 15 amino-terminal amino acid residues were H-DEQGNRPVETENIAR. Platelet aggregation activity of Sm-hPAF was abolished by heating at 45 degrees C for 10 min. Platelet aggregation by Sm-hPAF was accompanied by a release of prostaglandin E2 (PGE2) in a dose-dependent manner. The platelet aggregation was not inhibited by either prostaglandin E1 (PGE1) or Gly-Arg-Gly-Asp-Ser (GRGDS), that inhibit the platelet aggregation induced by collagen. Twenty (77%) platelet rich-plasma (PRP) specimens derived from 26 healthy volunteers were aggregated by Sm-hPAF, but the remaining 6 (23%) were not reactive. A preliminary study suggested the presence of an inhibitory factor against Sm-hPAF in the plasma from a non-reactive donor.

Identification of extracellular phospholipase B, lysophospholipase, and acyltransferase produced by Cryptococcus neoformans

We recently identified phospholipase activity as a potential virulence factor of Cryptococcus neoformans. We have now defined the nature of the phospholipase activity produced by a clinical isolate of C. neoformans var. neoformans, under native conditions, by 1H and 31P nuclear magnetic resonance (NMR) spectroscopy and thin-layer chromatography (TLC) of radiolabelled substrates. Glycerophosphocholine was identified by NMR spectroscopy as the sole phospholipid degradation product of the reaction between substrate phosphatidylcholine (PC) and cryptococcal culture supernatants indicating the presence of phospholipase B (PLB). No lysophosphatidylcholine (lyso-PC) or products indicative of phospholipase C, phospholipase D, or other lipase activity were identified. Use of PC and lyso-PC containing radiolabelled acyl chains and separation of products by TLC confirmed the PLB and lysophospholipase (LPL) activities. Lysophospholipase transacylase (LPTA) activity was identified by the formation of radioactive PC from lyso-PC. Extracellular enzyme production was maximal after 6 to 10 h in fresh medium. Assay conditions were optimized for pH, linearity with time, enzyme concentration, and saturation by substrates to allow comparison with phospholipases from other organisms. LPL activity was 10- to 20-fold greater than PLB activity, with mean (+/- standard deviation) specific activities of 34.9 +/- 7.9 and 3.18 +/- 0.2 micromol of substrate hydrolyzed per min per mg of protein, respectively. The response of PLB to increasing substrate concentrations was bimodal, whereas inhibition of LPL and LPTA activities occurred at concentrations of substrate lyso-PC greater than 200 microM. Enzyme activities were stable at acid pH (3.8), with pH optima of 3.5 to 4.5. Activities were unchanged in the presence of exogenous serine protease inhibitors, divalent cations, and EDTA. We conclude that C. neoformans produces highly active extracellular PLB, LPL, and LPTA under native conditions.

Immunological analysis of extracellular products and cell surface components of motile Aeromonas isolated from fish

The present work describes the characterization of antigens present in the extracellular products (ECP) and cell wall of strains of motile Aeromonas isolated from rainbow trout culture systems. The relationships among virulence for fish, O-serogroup and profile of LPS were also examined. The slide agglutination test showed that most of the virulent strains of motile Aeromonas (72%) were included in the serotypes O3, O6, O11 and O19 (Guinée and Jansen System). However, there were also non-pathogenic strains within these groups. Electrophoretic analysis of lipopolysaccharides (LPS) and proteins from cell envelope and ECP showed heterogeneity not only among the different serogroups but also within the same serotype. Immunoblot assays of cell envelope components, and of LPS present in the ECP demonstrated a close relationship among Aeromonas strains from the same serotype, while strains from different serotypes were not immunologically related. Moreover, this assay showed that motile Aeromonas belonging to distinct serotypes produced extracellular proteins immunologically related. On the other hand, antigenic cross reactivity was observed between the LPS obtained from cell envelope and those obtained from the ECP. The present results point out the need to include strains representative of each of the serotypes which predominates in a particular area and their ECPs in the formation of vaccines against motile Aeromonas septicaemia.

Bacteria in the bloodstream are trapped in the liver and killed by immigrating neutrophils

The critical role of the liver in the resolution of systemic bacterial infections is well documented. In the case of Listeria monocytogenes, approximately 60% of bacteria inoculated i.v. into mice are recovered in the liver at 10 min after infection. Here we report that the Listeria recovered at 10 min were distributed equally among the hepatocyte and nonparenchymal liver cell populations. The majority (>/= 75%) of these organisms were bound extracellularly as judged by their sensitivity to gentamicin. In contrast, >/= 93% of Listeria recovered in the liver at 6 h were located within hepatocytes. The listerial burden of the liver decreased 0.5 to 1.0 log, between 10 min and 6 h after infection. This decrease correlated with a sevenfold increase in the percentage of neutrophils that constituted the nonparenchymal cell population. Mice rendered neutrophil deficient by pretreatment with anti-granulocyte (RB6-8C5) mAb exhibited a significant increase (>300%) rather than a decrease in liver Listeria and a marked increase in hepatocyte damage. Similarly, neutrophil-deficient mice exhibited a reduced capacity to eliminate Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus that were cleared by the liver and bound extracellularly to hepatocytes and nonparenchymal cells. These findings document the crucial role of immigrating neutrophils in nonspecific host defenses to systemic bacterial infections expressed within the liver.

Extracellular proteinase activity of Cryptococcus neoformans

Extracellular proteinase activity was studied for eight strains of Cryptococcus neoformans var. neoformans and two strains of Cryptococcus neoformans var. gattii. Proteinase activity was measured by protein agar clearance, azoalbumin hydrolysis, gelatin liquefaction, and protein substrate polyacrylamide gel electrophoresis. All strains of C. neoformans produced extracellular proteolytic activity. Maximal extracellular proteinase activity in supernatants of C. neoformans cultures was associated with late logarithmic- and stationary-phase cultures. C. neoformans was able to utilize murine immunoglobulin G1, bovine immunoglobulin G, and human complement factor 5 for growth in media containing these proteins as the sole sources of carbon and nitrogen, suggesting a capacity to degrade immunologically important proteins. Protein substrate polyacrylamide gel electrophoresis revealed several bands with proteolytic activity at apparent molecular masses of 200, 100, and 50 kDa. The results confirm the existence of extracellular proteinase activity for C. neoformans.

Cystic fibrosis airway epithelia fail to kill bacteria because of abnormal airway surface fluid

Despite an increased understanding of the cellular and molecular biology of the CFTR Cl- channel, it is not known how defective Cl- transport across airway epithelia causes chronic bacterial infections in cystic fibrosis (CF) airways. Here, we show that common CF pathogens were killed when added to the apical surface of normal airway epithelia. In contrast, these bacteria multiplied on CF epithelia. We found that bactericidal activity was present in airway surface fluid of both normal and CF epithelia. However, because bacterial killing required a low NaCl concentration and because CF surface fluid has a high NaCl concentration, CF epithelia failed to kill bacteria. This defect was corrected by reducing the NaCl concentration on CF epithelia. These data explain how the loss of CFTR Cl- channels may lead to lung disease and suggest new approaches to therapy.

In-vitro activity of azithromycin in against intracellular Helicobacter pylori

We studied the effect in vitro of azithromycin on the clinical strain Helicobacter pylori H:72 growing intracellularly in monolayers of HEp-2 epithelial cells. After using gentamicin to eradicate extracellular bacteria, different concentrations of azithromycin were added to the infected cells and samples were taken after 0, 4, 8 and 24 h. Infected cells not exposed to antibiotic were included as controls. The MIC of azithromycin to the H. pylori was 0.25 mg/L and the MBC 0.5 mg/L in a broth dilution plate count method. A bactericidal effect was observed on intracellular H. pylori, with inhibition increasing with increasing azithromycin concentrations. However, extracellular concentrations of 200 x MBC were necessary to achieve intracellular killing. Our results show that azithromycin is active against intracellular H. pylori suggesting that it might be possible to exploit this activity when treating infections due to the organism.

Differentiated U937 cells and human monocytes exhibit a differential production of extracellular oxygen species: O2.- excretion versus H2O2 diffusion

The nature and the localization of the oxidative response triggered by different stimuli in either differentiated U937 cells and peripheral blood-derived human monocytes was investigated using luminometric and cytofluorometric techniques. Differentiated U937 cells essentially produced extracellular superoxide anion (O2.-), whatever the stimulus used. Monocytes, however, responded to Salmonella typhimurium, phorbol esters, and opsonized zymosan by an intracellular, an extracellular, and both an intra- and extracellular production of oxygen species, respectively. Furthermore, H2O2 but not O2.- was detected in the extracellular oxidative response of monocytes. Using differentiated U937 cells, luminol was found to be as efficient as lucigenin in the detection of extracellular O2.-, providing sufficient concentrations of extracellular horseradish peroxidase were present. However, both azide and histidine inhibited the lucigenin-enhanced chemiluminescence, suggesting an initial and transient production of singlet oxygen by differentiated U937 cells. Taken together these results strongly suggest that, when stimulated, differentiated U937 cells directly excrete O2.- in the extracellular medium while, within monocytes, O2.- is rapidly dismutated in H2O2 which can eventually diffuse outside the cell. Such differences in the oxidative response between the two cell types could be explained by the lack of total closure of the phagosome, only observed in differentiated U937 cells.

Extracellular and intracellular rickettsia-like microorganisms in gonads of mosquitoes

The mosquitoes Culex tigripes, C. decens and C. quinquefasciatus have been investigated by electron microscopy. An intracytoplasmic rickettsia-like microorganism is present in ovaries and testes of the three species. An extracellular form of a rickettsia-like microorganism is described in the testis of C. tigripes in which it sometimes appears in great number. The extra- and intracellular forms present ultrastructural differences. The possibility they represent two different morphotypes of the same microorganism or simply two different types is discussed. They both disappear after treatment with tetracycline. This is believed to be the first electron microscope description of extracellular rickettsia-like cells in mosquitoes.

The apoptotic suppressor P35 is required early during baculovirus replication and is targeted to the cytosol of infected cells

The p35 gene of Autographa californica nuclear polyhedrosis virus (AcMNPV) is required to block virus-induced apoptosis. The trans-dominant activity of p35 suppresses premature cell death and facilitates AcMNPV replication in a cell line- and host-specific manner. To characterize the p35 gene product (P35), a specific polyclonal antiserum was raised. As revealed by immunoblot analyses of wild-type AcMNPV-infected cells, P35 appeared early (8 to 12 h) and accumulated through the late stages of infection (24 to 36 h). Biochemical fractionation of cells both early and late in infection and indirect immunochemical staining demonstrated that P35 localized predominantly to the cytosol (150,000 x g supernatant); comparatively minor quantities of P35 were associated with intracellular membranes. The cytoplasmic localization of P35 was independent of virus infection. The functional significance of the early and late synthesis of P35 was examined by constructing recombinant viruses in which the timing and level of p35 expression were altered. Delaying P35 synthesis by placing p35 under exclusive control of a strong, very late promoter failed to suppress intracellular DNA fragmentation and apoptotic blebbing in most cells. Thus, earlier expression of p35 was required to block virus-induced apoptosis. Site-specific mutagenesis of the p35 promoter demonstrated that low levels of P35 were sufficient to block apoptosis, whereas higher levels were required to maintain wild-type virus gene expression. Consistent with an early role in infection, P35 was also detected in the budded form of AcMNPV. Because of the lack of sequence similarity and its cytosolic targeting, P35 may function in a manner that is mechanistically distinct from other apoptotic regulators, including Bcl-2 and the adenovirus E1B 19-kDa protein.

In vitro extracellular and intracellular activities of clavulanic acid and those of piperacillin and ceftriaxone alone and in combination with tazobactam against clinical isolates of Legionella species

The activities of ceftriaxone, piperacillin, tazobactam, clavulanic acid, and combinations of ceftriaxone or piperacillin with tazobactam against 22 clinical Legionella isolates were measured by broth microdilution and macrodilution methods and in macrophages. The broth microdilution MICs that inhibited 90% of strains tested were 2 and 1 microgram/ml for ceftriaxone and tazobactam, respectively. Broth macrodilution MICs were 8 and 1 microgram/ml, respectively, for the two Legionella pneumophila strains tested with piperacillin and were 0.25 and 0.5 microgram/ml, respectively, for clavulanate. No significant intracellular anti-L. pneumophila activity was observed for ceftriaxone (32 micrograms/ml), piperacillin (32 micrograms/ml), tazobactam alone (16 micrograms/ml), clavulanate alone (2 micrograms/ml), or tazobactam in combination with ceftriaxone (ceftriaxone/tazobactam at 32/4 and 16/16 micrograms/ml) or piperacillin (32/4 micrograms/ml). Erythromycin (1 microgram/ml) was active against intracellular L. pneumophila in the same macrophage model of infection. It is very unlikely that tazobactam or clavulanate, alone or in combination with beta-lactam antimicrobial agents, will be effective for the treatment of Legionnaires' disease in humans.

Binding of bacterial adhesins to rat glomerular mesangium in vivo

Two well characterized bacterial adhesins, the O75X fimbriae of Escherichia coli and the type-3 fimbriae of Klebsiellae, with in vitro affinities to type IV and V collagens, respectively, were used to test whether bacterial components with affinity for glomerular matrix could bind to glomeruli in vivo. The purified fimbrial proteins were injected into rats, and kidney samples were studied by immunofluorescence at two hours to nine months postinjection. The O75X, but not the type-3 fimbriae, formed mesangial deposits that persisted for months. Preincubation of the O75X fimbriae with type IV collagen significantly reduced the glomerular binding. The fimbrial deposits were extracellular, as anti-O75X IgG injected into rats bound to glomeruli. Proteinuria or histological damage could not be detected even after passive or active immunizations of the rats. The results demonstrate that bacterial adhesins may bind in vivo to and persist in glomeruli by their specific affinities. The results also indicate that additional factors provided by the bacteria or the host are needed for glomerular damage to take place.

In vitro activity of Ro 23-9424 against clinical isolates of Legionella species

Agar and broth microdilution MICs of Ro 23-9424 that inhibited 90% of 22 Legionella clinical isolates tested were 0.64 and 0.08 micrograms/ml, respectively; respective erythromycin values were 1.0 and 0.12 micrograms/ml. Ro 23-9424 (1 microgram/ml) was slightly more active than the same erythromycin concentration in a macrophage system, for both Legionella pneumophila strains studied.

icsB: a Shigella flexneri virulence gene necessary for the lysis of protrusions during intercellular spread

Shigella flexneri causes bacillary dysentery by invading epithelial cells of the colonic mucosa. We have characterized the icsB gene which is located on the virulence plasmid pWR100. After inactivation of icsB, the mutant strain remained invasive, but formed abnormally small plaques on HeLa cell monolayers, colonized only the peripheral cells of Caco-2 islets, and was unable to provoke a keratoconjunctivitis in guinea-pigs. Examination of infected HeLa cells showed that the icsB mutant was able to lyse the phagocytic vacuole and to form protrusions at the surface of infected cells, but, unlike the wild type, remained trapped in protrusions surrounded by two membranes. These results indicate that IcsB is involved in the lysis of the protrusions, a step necessary for intercellular spread.

Bacterial invasion of periodontal tissues after experimental immunosuppression in rats

A moderate gingivitis was produced in 3 groups of 10 adult Wistar rats with diet 2000 of Keyes and Jordan (1964) delivered for 30 days with a controlled feeding unit. The first group served as untreated control. The second group received 5 intraperitoneal injections of cyclosporine A (15 mg/kg body weight) from day 20 to 30 to interfere with the activation of T lymphocytes and interleukin synthesis. The third group received 2 intraperitoneal injections of cyclophosphamide (100 mg/kg on day 20 and 25) which induced a severe neutropenia. The gingival areas between the upper molar regions were prepared for light and transmission electron microscopy. In the untreated control group, a layer of polymorphonuclear neutrophils (PMN) was observed between the dental plaque and the junctional epithelium with a round cell infiltration in the superficial connective tissue. No bacterial invasion was observed. In the cyclosporine group, despite the action on T lymphocytes, no bacterial invasion occurred, but a differentiated PMN layer was present between the apical dental plaque and the junctional epithelium. In the cyclophosphamide group an important bacterial invasion was observed in the interdental epithelium as well as in the underlying connective tissue. In the local absence of PMNs, a mixed flora of Gram positive and negative bacteria of various shapes invaded epithelial as well as connective tissue cells and came in contact with the alveolar crestal bone. Resorption of the alveolar crestal bone scored according to the Keyes and Gold method (1955) was significantly more important in the cyclosporine and the cyclophosphamide group when compared to the controls (p less than 0.05). No statistical difference in bone resorption was noted between the cyclosporine and the cyclophosphamide groups. It can be concluded that the PMN layer constitutes the first line of defense opposed to bacterial invasion of the periodontal tissues.

[Fundamental study on the collection of prostatic fluid using catheter]

The catheter for expressed prostatic secretions (EPS) collection was newly developed for the purpose of protecting EPS from the contamination of the urethral bacteria. This catheter is blind-ended, and has several lateral windows and a balloon between the end and the windows. The procedure of EPS collection using this catheter is as follows; first the catheter is inserted into the urethra, then a balloon is blown up. The catheter is extracted during massage of the prostate and finally EPS is aspirated through the internal lumen of the catheter. In 23 male patients who had neither urinary tract infection nor genital infection, this catheter method was carried out. Before inserting the catheter, the urethral swab was obtained, then culture of the swab and the EPS was done. The catheter method protected against contamination with bacteria in 56%, with Ureaplasma urealyticum in 40%, and all contaminations in 44% of all cases.

[Clinical study of new technique for collection of EPS, prostate catheter method--comparison with Meares and Stamey's method]

We newly developed a catheter for expressed prostatic secretions (EPS) collection and examined whether or not EPS can be collected with this catheter without contamination of urethral bacteria. The clinical value of the prostate catheter method was examined in comparison with Meares & Stamey's method. Both prostate catheter and Meares & Stamey's method were performed by crossover method in 11 patients who were highly suspected of chronic prostatitis based on symptoms and physical findings. Three of the 4 cases of bacterial prostatitis on Meares & Stamey's method were diagnosed as bacterial prostatitis by the prostate catheter method, but the remaining one was diagnosed as prostatodynia. One of the 3 cases of non-bacterial prostatitis on Meares & Stamey's method was diagnosed as non-bacterial prostatitis, but the other two cases were diagnosed as urethritis. Four cases of prostatodinia on Meares & Stamey's method were given the same diagnosis by the prostate catheter method. In conclusion, eight of 11 cases received the same diagnosis by the two different method. The remaining three cases were given different diagnosis, but the prostate catheter method gave a more accurate diagnosis. We concluded that the prostate catheter method is useful in the differential diagnosis of bacterial prostatitis and non-bacterial prostatitis.