Morphological examination of cell surface structures of enterotoxigenic strains of Escherichia coli

The very fine sinuous K99 pili of enterotoxigenic strains of Escherichia coli can be visualized in shadowed and in negatively stained preparations, especially if the amorphous K30 glycocalyx is not produced, but these very delicate structures cannot be directly resolved in sectioned material. The K99 pili can, however, be thickened by the nonspecific accretion of K30 glycocalyx material, during its condensation as a result of dehydration, to the point where it can be resolved in sectioned material. This visualization is enhanced if the accreted and condensed glycocalyx is stained with ruthenium red. Alternatively and additionally, the K99 pilus can be thickened by the specific accretion of monoclonal antibodies so that it is made visible in sectioned material. The condensation of the hydrated K30 antigen glycocalyx of enterotoxigenic strains of Escherichia coli during dehydration can be prevented by stabilization using specific antibodies so that this capsular glycocalyx structure is identified in sectioned material and is seen in its correct distribution and dimensions. These methods allow the identification and visualization of bacterial surface structures, both in vitro and in vivo, and they provide a useful means of assessing the presence and distribution of these structures at all stages of the bacterial disease and a possible means of assessing their roles in the pathogenic process.

Biological evaluation of some ionophore-polymeric chelator combinations for reducing iron overload

The potential efficacy of drug combinations that employ an ionophore to mobilize excess hepatic Fe and transport it to the gut for chelation to nonabsorbable polymers and excretion was evaluated in three ways: 1) two-phase partition experiments to assess the ionophoretic capability of lipid-soluble Fe(III)-chelators; 2) in vitro screening with Fe-loaded hepatocyte cultures; and 3) evaluation in Fe-dextran-loaded mice given a low-Fe-containing diet for maximal sensitivity. In the partition experiments, desferal (DF), (desferri)ferrichrome, pyridoxyl isonicotinoyl acid hydrazone hydrochloride (PINH), 2,3-dihydroxybenzoic acid, cholylhydroxamic acid and caffeic acid were effective to varying degrees in transferring Fe(III) from an aqueous to an organic hydrophobic phase. PINH, the most effective, combined with poly[vinylamine-vinyl(2,3-dihydroxybenzenecarboxamide)-vinyl sulfonate sodium salt] (DHBP), increased net 59Fe release from Fe-loaded hepatocytes above the sum of that released by each drug alone and comparable with DF-induced levels. In the mouse bioassay, the combination of PINH (8.1 mg/kg) and DHBP (170 mg/kg 2 times daily) caused a 32% increase in fecal Fe output, comparable with total Fe excretion with DF, but higher doses were toxic and lower doses ineffective. Furthermore, less than 5% of the total Fe load administered was excreted during the 4-day treatment period by either DF or the PINH-DHBP drug combination.

Influence of culture conditions on expression of the mucoid mode of growth of Pseudomonas aeruginosa

Five strains of Pseudomonas aeruginosa that are routinely distinguished by diagnostic laboratories on the basis of their colony morphology on agar media were grown in different media to assess the effects of culture conditions on mucoid growth, which we define as the copious production of exopolysaccharide. On brain heart infusion agar, only two of these strains (mucoid and gelatinous) grew as slimy mucoid colonies. None of the five strains produced a mucoid pattern of growth in Mueller-Hinton broth, in which all grew as turbid, nonmucoid, homogeneous suspensions of bacterial cells. When Mueller-Hinton broth was supplemented with Mg2+, all of the strains produced some mucoid aggregated growth, but growth in a modified version of the chemically defined medium of Vogel and Bonner, with elevated levels of Mg2+ and gluconate, produced patently mucoid growth in all strains. This mucoid growth in a liquid medium takes the form of large, coherent, slimy aggregates within the medium and of a "collar" of adherent microcolonies at the air-medium interface. Direct observations by light and electron microscopy showed the submerged aggregates and the adherent microcolonies to be composed of bacterial cells enmeshed in a copious exopolysaccharide matrix. When agar was added to the supplemented medium of Vogel and Bonner, only the mucoid and gelatinous strains produced slimy mucoid colonies on its surface. We conclude that both chemical and physical factors affect exopolysaccharide production by these clinical strains of P. aeruginosa and that the colony morphology on a single agar medium is an insufficient criterion for the designation of a given isolate as being mucoid or nonmucoid.

Anti-glucocorticoids block the enhancement of mouse mammary tumor virus production by 12-O-tetradecanoylphorbol-13-acetate

Four anti-glucocorticoids, 11-deoxycortisol, deoxycorticosterone, 17 alpha-methyltestosterone and progesterone were demonstrated to antagonize the stimulation of mouse mammary tumor virus (MMTV) production by the glucocorticoid hormone dexamethasone in the cell line Mm5mt. These same anti-glucocorticoids were also able to suppress the enhancement of MMTV production by the tumor promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), whereas estradiol, the anti-tumor promoter trans-retinoic acid, and the calmodulin inhibitor, chlorpromazine did not. Binding competition studies indicate that TPA can compete with dexamethasone in binding to the cellular glucocorticoid receptor. These results suggest that TPA stimulates the expression of MMTV by mimicking a glucocorticoid hormone.

The role of the microcolony mode of growth in the pathogenesis of Pseudomonas aeruginosa infections

In nature Pseudomonas aeruginosa grows in two modes, the mobile "swarmer" cell and the glycocalyx-enclosed microcolony. The microcolony mode is numerically dominant perhaps because it provides adhesion in a favorable niche and protection from bacteriophages and phagocytic predators. When this organism colonizes the compromised human host, a broad spectrum of different types of infection is produced, ranging from asymptomatic persistent cystitis to the overwhelming bacteremia seen in neutropenic patients. These infections differ radically both in their degree of toxicity and invasiveness and in their susceptibility to control with specific antibodies and/or antibiotics. These differences may reflect the degree to which intact host defense mechanisms force the bacteria to adopt the defensive, microcolony mode of growth. As examples, the nearly intact host defense mechanisms and vigorous immune response of patients with cystic fibrosis force P. aeruginosa in pulmonary infections into a demonstrably cryptic, microcolony mode of growth that allows its persistence in the face of specific antibodies and antibiotics but limits its toxic activity and its dissemination. In contrast, the ruined defense mechanisms of burned skin allow the spread of bacteria in the mobile mode; toxic effects are seen in neighboring tissues, and a mixed mobile-microcolony reservoir population, whose mobile members can subsequently invade the circulatory system, is built up in the burned tissue. Thus, it is important to define the mode of bacterial growth in each type of P. aeruginosa infection and, where the microcolony mode is predominant, to understand the chemistry of the enveloping exopolysaccharide in order to limit its synthesis and/or facilitate its penetration by antibodies and antibiotics.

Aromatic retinoic acid analogues. 2. Synthesis and pharmacological activity

Aromatic analogues of (E)-1-(4-carboxyphenyl)-2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)butadiene (1b) and its ethyl ester (1a) were synthesized as potential chemopreventive agents for the treatment of epithelial cancer and such skin diseases as psoriasis and cystic acne. The phenyl ring of 1 was replaced by 2-fluorophenyl, 2-methoxyphenyl, thienyl, furanyl, and pyridyl groups. The 1-fluorobutadiene analogue of 1 was also synthesized. With exception for the furanyl analogue, these compounds demonstrated good activity in reversing keratinization in hamster tracheal organ culture and in inhibiting the induction of ornithine decarboxylase in mouse epidermis by a tumor promoter.

The use of specific antibodies to demonstrate the glycocalyx and spatial relationships of a K99-, F41- enterotoxigenic strain of Escherichia coli colonizing the ileum of colostrum-deprived calves

Electron microscopy was used to study the interaction between the glycocalyx of enterotoxigenic Escherichia coli strain 210 (09:K30+;K99-;F41-:H-) and the glycocalyx of epithelial cells in then ileum of experimentally infected newborn colostrum-deprived calves. Fixation of tissues in anti-K30 antibody and ruthenium red was used to stabilize the bacterial glycocalyx so that the spatial relationship between the bacteria and the intestinal epithelial cells could be characterized. When strain 210 was grown in vitro and reacted with anti-K30 antibody prior to staining with ruthenium red, the extensive glycocalyx could be clearly visualized surrounding the bacterial cells. By negative staining, an unidentified pilus was also seen. Sections of ileum from infected calves, which were not fixed in antibody nor stained with ruthenium red, revealed attached bacteria which were surrounded by an electron-translucent zone and no visible bacterial glycocalyx. When ruthenium red staining was used, the bacterial glycocalyx partially collapsed during the dehydration steps of fixation, but could be seen as either a fibrous capsule or an electron-dense accretion on the bacterial cell surface. When ileal tissue was reacted for one hour in anti-K30 antibody before staining with ruthenium red, the bacterial glycocalyx was seen as a discrete electron-dense structure up to 1.0microm thick which was in intimate contact with the glycocalyx of the epithelial cells. The importance of the bacterial exopolysaccharide to microcolony formation on the villi could be clearly visualized.

Dinitro and mononitrobenzo(ghi)perylenes and mononitrocoronene are highly mutagenic in the Ames Salmonella assay

Benzo(ghi)perylene (B(ghi))Per, (191-24-2)) and coronene (Cor, (191-07-1)) are major constituents of the polycyclic aromatic hydrocarbons (PAH) found in automobile exhaust and polluted air [eg, Grimmer et al, 1981]. Nitration of these PAH by NO2 and traces of HNO3, which are also formed in automobile exhaust, seems highly probable. To identify the presence of these nitroarenes in environmental samples and to examine their mutagenic potencies we synthesized and characterized nitro derivatives of both PAH. 5-NO2B(ghi)Per (81316-87-2) and 1-NO2Cor (81316-84-9) produced 405 and 340 revertants/nmole respectively in TA98 in the presence of 0.6 mg of microsomal enzymes (S-9) per plate in the Ames test. 5,8-diNO2B(ghi)Per (83292-25-5) and 5,10-diNO2B(ghi)Per (83292-26-6) produced 21,500 and 4,000 revertants/nmole in TA98 without microsomal activation. Mutagenicity for the dinitrobenzo(ghi)perylenes was also high in TA98NR and TA97 but was reduced by 97% in TA98-1,8DNP. There is close similarity in the orientation and distances between reactive sites (nitrenium ion and carbocation) on the dinitrobenzo(ghi)perylenes and 1,6-dinitropyrene (42397-64-8) and 1,8-dinitropyrene (42397-65-9).

Use of specific antibody to demonstrate glycocalyx, K99 pili, and the spatial relationships of K99+ enterotoxigenic Escherichia coli in the ileum of colostrum-fed calves

The attachment of enterotoxigenic Escherichia coli (ETEC) strain B44 (O9:K30:K99:F41:H-) to the ileal epithelium of newborn colostrum-fed calves was studied by electron microscopy. Stabilization of the bacterial glycocalyx (K30) and pili (K99) by fixation of tissue sections in specific antibody and staining with ruthenium red were used so that the bacterial surface structures could be clearly visualized and their spatial relationship to the intestinal brush border defined. When sections of ileum from infected calves were neither fixed in antibody nor stained with ruthenium red, the ETEC cells colonizing the small intestine were separated from each other and from the brush border by an electron-translucent halo; neither the glycocalyx nor the pili could be clearly resolved. When ruthenium red staining was used, the halo was partially filled by a net of electron-dense fibers composed of pili and condensed glycocalyx which extended to the brush border. Tissue sections reacted with anti-K30 antibody before staining with ruthenium red revealed microcolonies of ETEC surrounded by a discrete electron-dense glycocalyx 0.3 to 1.0 micrometers thick and in tight contact with the epithelial cell surface. When ileal tissue was treated with K99 antibody, the K99 pili were visible as discrete fibers extending from the bacterial cell surface through the glycocalyx. We discuss the role of these cell surface components in pathogenic adhesion and in the formation of protected microcolonies at the surface of the infected ileal epithelium.

Pasteurella multocida subdural empyema: a case report

The first case of Pasteurella Multocida subdural empyema is reported. This was secondary to hematogenous spread from the pharynx to a chronic subdural hematoma. Positive cultures were obtained from the primary source, the blood and the subdural space. The patient was discharged with no neurological deficit following surgical drainage and parenteral antibiotics. The incidence, predisposing factors, clinical features, bacteriology, diagnostic procedures, treatment and mortality of subdural empyema are briefly discussed.

Corynebacterium diphtheriae septicemia

This report describes the case of a patient with chronic lymphocytic leukemia in whom septicemia caused by a nontoxigenic strain of Corynebacterium diphtheriae developed. Numerous abscesses were present in sections of liver and spleen taken at autopsy. The case is discussed, and the literature on infections caused by organisms of the genus Corynebacterium is briefly reviewed.

Citrate-tris(hydroxymethyl)aminomethane-mediated release of outer membrane sections from the cell envelope of a deep-rough (heptose-deficient lipopolysaccharide) strain of Escherichia coli O8

A heptose-deficient lipopolysaccharide strain of Escherichia coli O8, strain F515, was found to release portions of its outer membrane when cells were exposed to 10 mM citrate buffer (pH 2.75) for 30 min and subsequently exposed to 100 mM tris(hydroxymethyl)aminomethane buffer (pH 8.00). The outer membrane component release was found to be composed of protein, lipopolysaccharide, phospholipid (cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol), and alkaline phosphatase. The outer membrane component was released from the cell envelope in the absence of cell lysis, as no glucose-6-phosphate dehydrogenase activity or succinic dehydrogenase activity was detected. Morphologically, the outer membrane component appeared to consist of laminar fragments and vesicles which had an associated alkaline phosphatase activity.

5-fluorouracil and cis-platinum in the treatment of refractory solid tumors: a pediatric oncology group phase I-II study

Eleven patients with osteogenic sarcoma (9), Hodgkin disease (1), and mesenchymal sarcoma (1), were treated with 5-fluorouracil (5-FU) and cisplatin (DDP). Myelosuppression and vomiting of variable degrees occurred in all. No responses were seen.

[Assessment of the surgical risk by skin tests of cell-mediated reactivity and other methods]

In examining some procedures of general evaluation of the operative risk the Authors direct their attention to the performance of cell-mediate reactivity skin tests and consider a set of 42 patients (of whom 11 as controls, and 31 "high risk"). The results obtained are interesting and evidence the high reliability of these tests in evaluation of infective morbidity and mortality in neoplastic and non-neoplastic patients: in fact a negative response means high morbidity and mortality while a positive response corresponds to normal surgical healing. In tumoral patients, moreover a relationship between skin tests and clinical stage of the disease is observed: negativity of the test means a terminal stage and hence absolute inoperability: positivity corresponds to an advanced stage and hence relative operability (exploratory laparatomy and thoracotomy). The Authors conclude by stressing that the tests have a practical utility and prognostic value higher than those of other methods.

Radiotherapy (2500 rad) for testicular leukemia: local control and subsequent clinical events: a Southwest Oncology Group study

The effectiveness of radiotherapy, 2500 rad over two weeks, in treating leukemic infiltrates of the testicles was studied in 38 boys who met the requirements for tissue conformation of testicular involvement and examination of the bone marrow. The study group was heterogeneous with respect to specific histology and prior therapy. Complete regression of testicular infiltrates was confirmed by repeated biopsy examinations of 32 of 33 patients undergoing the procedure. The single treatment failure occurred in a boy with acute myelogenous leukemia. In all other patients, local disease control following radiotherapy persisted throuthout the remainder of the clinical course. Three of 5 children, however, showed evidence of reseeding of the testicle as a part of the relapse process at post-mortem examination. Statistical analysis of data from the 35 patients with acute lymphocytic leukemia showed the subsequent course of the disease with respect to next relapse, involving either bone marrow (BM) or the central nervous system (CNS), to be dependent on the acute leukemia prognostic group, as determined by age and peripheral white blood cell count (WBC) at the time of diagnosis, and timing of extramedullary disease (EMD). Patients with poor prognosis at the time of diagnosis and EMD afterward had a 3.8 times greater risk of a subsequent BM or CNS relapse than did patients with good or average prognosis and no EMD at any time (P = 0.07). Of the candidate prognostic factors examined with repect to survival, only the number of prior BM relapses was of statistical significance (P = 0.044). Children with two or more prior BM relapses had the worst prognosis for survival from testicular relapse, with a death risk of 3.6 times greater per unit of time than that of children with no or one prior BM relapse. Protective BM and CNS rescue therapy was recommended for those otherwise in complete remission (CR) at the time of testicular relapse. The median times to next relapse for patients receiving both BM and CNS recue therapy and for patients given CNS recue only were 42+ and seven weeks, respectively ( P = 0.09). The type of rescue received did not appear to affect survival time following testicular CR.

Production of mucoid microcolonies by Pseudomonas aeruginosa within infected lungs in cystic fibrosis

Direct electron microscopic examination of postmortem lung material from cystic fibrosis patients infected with Pseudomonas aeruginosa has shown that these bacterial cells form distinct fiber-enclosed microcolonies in the infected alveoli. Similar examination of bronchoscopy material from infected cystic fibrosis patients showed that the fibres of the enveloping matrix are definitely associated with the bacterial cells. The fibers of the extracellular matrix stain with ruthenium red and are therefore presumed to be polyanionic. When mucoid strains of P. aeruginosa were recovered from cystic fibrosis patients and grown in a suitable liquid medium, they were found to produce large microcolonies whose component cells were embedded in a very extensive matrix of polyanionic fibers that could be stabilized by reaction with antibodies to prevent collapse during the dehydration steps of preparation for electron microscopy. When these mucoid strains of P. aeruginosa were used to produce pulmonary infections of rats by the agar bead method, the infected alveoli contained large fiber-enclosed bacterial microcolonies. We conclude that the cells of P. aeruginosa that infect cystic fibrosis patients form microcolonies that are enveloped in a fibrous anionic matrix and that these microcolonies can be duplicated in in vitro cultures and in animal model systems.

Distribution of types of Streptococcus pneumoniae isolated in Sydney in 1973--1974 and in 1979

At The Prince of Wales Hospital, 357 pneumococci isolated in the laboratory from September, 1973, to May, 1974, and 268 pneumococci isolated from June to November, 1979, were serotyped. The pneumococci were isolated from patients and carriers in the hospital and in general practice. The type distribution resembled that described by Hansman regarding 1247 pneumococci isolated from 1965 to 1969. In each of the periods, the same seven predominant types--19, 23, 6, 3, 9, 11 and 15--were isolated in almost exactly the same order of frequency. Of the "epidemic" types--1, 2, 4, 5, 7 and 12--only type 12 was not isolated in the present study. This information may be of value in the choice of components for an appropriate polyvalent pneumococcal vaccine for susceptible children and adults in Australia.

[Heterotopic homograft of the rat stomach: microsurgical technic]

More than by a practical viewpoint, the experimental graft of stomach is very useful like model for the study of gastrointestinal physiopathology. Starting from these considerations the AA. have set up a new method for the execution of stomach heterotopic homograft in rat and they have studied the secretory activity without immuno-suppressed therapy. Not inbred rats have been used; their middle survival has been of 9,3 days. The secretion has been regular up to 5th-6th day; in the same time the AA. have made histopathologic studies on the transplanted stomachs of animals that had been sacrificed at programmed intervals of time, which have outlined the progressive growth of a reaction of intense immunological rejection.

[Orthotopic homograft of the rat stomach: microsurgical technic]

The principal aim of this study is to set up a new microsurgical technique that can be reproducible easily for the execution of orthotopic homograft of stomach in rat. The vascularization of homograft is given, for arterial district by a termino-terminal anastomosis between celiac artery of donor and right renal artery of receiving, and, for venous district, by a termino-lateral anastomosis between portal vein of donor and vena cava of receiving. The middle survival of rats that were had a graft, in this first stage of research, has been of 3 days, therefore it hasn't't been possible to look into the function of graft.

[Mechanical sutures in digestive surgery. II. An experimental study of the cicatricial repair process]

The AA. intend to study the healing process of digestive sutures in dog that have been made with mechanical instruments that have metal agraphes. The used instruments are the American models of United Surgical Corporation in New York that have: --LDS pliers; --GIA pliers; --TA mod 90, 55, 30, pliers. They had made 15 operations of digestive surgery: gastric resections sec. Billroth II, anastomoses of ileum, colic anastomoses. In total they have made 45 sutures. After an established period the same animals were operated on again for controlling the results of made operations and the macro and microscopic evolution of sutures. The study of healing has shown a quick and exact repairing process for first intent, different from sutures that are made manually with threads that, notoriously, develop slowly for second intent.