Clostridial bacteremia in the community hospital.

Anaerobic infections are not commonly studied in the community hospital. The aim of this study was to determine demographic factors, the portals of entry and underlying disorders for clostridial bacteremia and to determine whether appropriate (recommended) treatment is effective. Medical records were reviewed for 42 patients with clostridial bacteremia at 1 Florida, USA, hospital and 4 Dayton, Ohio, USA, hospitals. Fourteen (33.3%) of the patients had clostridial micro-organisms that were isolated in cultures with polymicrobial isolates. Only about half of the patients had fever at the onset of their bacteremia and only slightly more than half had elevated leukocyte counts. The most common portals of entry for the micro-organisms were gastrointestinal (42.9%), unknown (35.7%) and skin (16.7%). The most common underlying disorders were advanced malignancy (31.0%), diabetes mellitus (14.3%), none determined (12.0%) and acute cholecystitis (9.5%). The mortality rate was 23.8%. Timely appropriate treatment was started in only about half of the instances. Appropriate (recommended) treatment did not significantly affect survival (p = 0.469). Clostridial infections and bacteremia exist in the community hospital most commonly in severely ill patients. The fact that clostridia are commonly cultured in blood cultures positive for other bacterial pathogens and that appropriate treatment for clostridia did not affect patient survival, call into question the significance and pathogenicity of clostridial organisms. On the other hand, if clostridial bacteremia was not considered in half these patients with bacteremia, it is possible that more indolent clostridial infections are being overlooked.

Immunochemical evidence supporting 2-pentylpyrrole formation on proteins exposed to 4-hydroxy-2-nonenal.

Previous model studies suggested the formation of lysine-based 2-pentylpyrroles as novel late adduction products formed upon exposure of proteins to the lipid peroxidation product 4-hydroxy-2-nonenal (HNE). Two 2-pentylpyrrole immunogens were prepared, one by treating keyhole limpet hemocyanin (KLH) directly with 4-oxononanal and the other by preformation of 6-(2-pentylpyrrol-1-yl)hexanoic acid from 6-aminocaproic acid and 4-oxononanal, followed by carbodiimide coupling to KLH. Pyrrole content and lysine modification in KLH were assayed independently. Following immunization of rabbits, antibody titer increased and plateaued over a 4 month period. The structural specificity of the IgG fractions of the antisera was evaluated through comprehensive competitive ELISA studies. These antibodies were used to verify the time-dependent appearance of the 2-pentylpyrrole epitope in protein exposed to HNE. Potential advantages of antibodies recognizing "advanced lipid peroxidation end products" over those recognizing "early" HNE adduction products are discussed.

Nosocomial infection in the community hospital: severe infection due to Serratia species.

BACKGROUND: Serratia bacteremia is an uncommon illness in hospitalized patients. The aim of this study was to determine how frequently this disease occurs nosocomially and to discover the most common portals of entry and the underlying disorders. METHODS: Fifty-six cases of Serratia bacteremia documented by blood culture (17 cases over a 4-year period in a community hospital in Gainesville, Florida, and 39 cases over a 3-year period in three community hospitals in Dayton, Ohio) were reviewed. Comparison was made with 60 control cases of general bacteremia from three Dayton hospitals. RESULTS: Of the 56 study cases of Serratia bacteremia, 45 (80.4%) were classified as nosocomial, compared with 13 (21.7%) of the controls. Twenty-seven (48.2%) of the 56 Serratia cases occurred in intensive care units. The cases were evenly distributed over the two study periods, and no outbreaks on specific units were noted. The most common portals of entry for Serratia organisms were, in descending order, lung, genitourinary tract, unknown, intravenous line, gastrointestinal tract, and skin. The most common underlying disorder for Serratia bacteremia was malignancy, followed by renal failure (acute or chronic) and diabetes mellitus. Most of the Serratia organisms tested were sensitive to carbenicillin, trimethoprim/sulfamethoxazole, ceftizoxime, ceftriaxone, ceftazidime, cefotetan, aztreonam, ticarcillin/clavulanate, and ciprofloxacin. The organisms were largely resistant to ampicillin, tetracycline, cefazolin, cephalothin, and cefuroxime. Twenty-five percent of the patients with Serratia bacteremia died, compared with 13.6 of the bacteremic controls. CONCLUSION: Serratia bacteremia is often acquired nosocomially. The mortality rate among the study population was surprisingly low for this opportunistic bacteremia, but was higher (though not significantly so) than that of the controls.

Mechanism-based inactivation of porcine kidney diamine oxidase by 1,4-diamino-2-butene.

Cis- and trans-1,4-diamino-2-butene are substrates and potent inactivators of porcine kidney diamine oxidase. Evidence from absorption and NMR spectra indicates that both are oxidized to pyrrole. Both substrates are irreversible mechanism-based inactivators of the enzyme, although the trans isomer is more potent and results in complete inactivation in a reaction which follows pseudo-first-order kinetics with an apparent Ki of 0.34 mM and a second-order inactivation constant of 500 M-1 s-1. Under the same conditions, 46% of the activity remains when the enzyme is reacted with cis-1,4-diamino-2-butene. Trans-4-amino-2-butenal, the product of oxidation of the trans diamine, has been synthesized and shown to undergo cyclization to pyrrole in a concentration-dependent manner, approaching second-order at low concentrations. Trans-4-amino-2-butenal is itself a potent irreversible inhibitor with IC50 of 2.5 microM. We propose that the irreversible inactivation by both cis- and trans-1,4-diamino-2-butene involves attack by a protein-based nucleophilic residue on the unsaturated aminoenal products of the enzymatic reactions, resulting in a covalent adduct. Cyclization of the cis-aminoenal to pyrrole is much more rapid than in the trans case, thus it is less available for inhibitory reaction with the protein.

Haemoprotein-mediated metabolism of enamines and the possible involvement of one-electron oxidations.

1. Microsomal metabolism of 1-benzylpiperidine (1-BP), its cis-2,6-dimethyl (cis-2,6-DMBP), 4,4-dimethyl (4,4-DMBP), and alpha, alpha-dimethyl (alpha, alpha-DMBP) analogues, and phencyclidine (PCP) has been studied to assess the involvement of P450 oxidation of the enamine tautomers of the initial endocyclic iminium metabolites. 2. The selective prevention by cyanide of the metabolite production of 1-benzyl-3-piperidone but not 1-benzyl-3-piperidinol from 1-BP is consistent with the enamine as the source of the 3-one metabolite. 3. The parent amines and particularly the independently prepared iminium species induced a pattern of metabolism-dependent irreversible inactivation of P450 benz-phetamine demethylase activity, consistent with involvement of enamine C-3 oxidation in the inactivation process. 4. Substrate activity of the endocyclic enamines and alpha-aminoketones (presumably the enol-enamine tautomers) for horseradish peroxidase under conditions where simple aliphatic amines display no activity is consistent with metabolic one-electron oxidations of the enamines.

Structural definition of early lysine and histidine adduction chemistry of 4-hydroxynonenal.

The lipid peroxidation product trans-4-hydroxy-2-nonenal (HNE) has been implicated in the covalent modification of low-density lipoproteins (LDL) thought to contribute to the over-accumulation of LDL in the arterial wall in the initial stages of atherosclerosis. Proposals for the exact structures of "early" protein side-chain modifications until now have been based on indirect evidence. In this paper, the structures of first-formed His- and Lys-based adducts were elucidated by correlating NMR spectral properties with those obtained on models with reduced chiral center content, in some cases following hydride reduction. In this manner, we could confirm unambiguously the structure of a HNE-His imidazole(N tau) Michael adduct, stabilized as a cyclic hemiacetal and isolated from a neutral aqueous 1:1 stoichiometry reaction mixture. In the case of Lys/amine reactivity, where an excess of amine is needed to avert HNE aldol condensation, the predominance of a 1:1 Michael adduct in homogeneous aqueous solution and a 1:2 Michael-Schiff base adduct under two-phase aqueous-organic conditions could be verified by isolation of the respective borohydride-reduced forms. The 1:2 adduct, shown to exist as the cyclic hemiaminal, could represent a stable lysine-based cross-link in certain protein microenvironments.

Faecal carcinoembryonic antigen (CEA) in patients with large bowel cancer.

The possibility that faecal CEA may be a more useful measurement than serum CEA for the detection of large bowel cancer has received very little attention. For this reason faecal CEA was measured before and after tumour resection in colorectal cancer patients and in a variety of control subjects. CEA was extracted from faeces by a new method with 3M KCl and assayed by an EIA technique utilising two monoclonal antibodies. Mean +/- SE faecal CEA in 32 cancer patients was 4.15 +/- 1.17 micrograms/g preoperatively. Values were not related to either stage of disease or serum CEA and they fell to 0.83 +/- 0.34 micrograms/g (n = 20) following tumour resection (P less than 0.05). Mean +/- SE faecal CEA in 34 control patients with no known colorectal disease was 0.94 +/- 0.49 micrograms/g which was significantly lower than in the cancer patients (P less than 0.05). Furthermore faecal CEA in 25 patients with non malignant colorectal disease was 1.44 +/- 0.63 micrograms/g which again was significantly lower than that in the cancer patients. It is concluded that as CEA is present in the faeces of the majority of colorectal cancer patients even at early stages of the disease its measurement here may be more useful for the detection of large bowel cancer than that in serum.

Faecal carcinoembryonic antigen in colorectal cancer patients.

Carcinoembryonic antigen (CEA) has been measured in the faeces of large bowel cancer patients and control subjects to determine whether this measurement might be a useful aid in the diagnosis of large bowel cancer. The mean faecal CEA in 24 cancer patients fell significantly from 10.43 +/- 2.39 micrograms/g pre-operatively to 3.61 +/- 0.72 micrograms/g postoperatively (p less than 0.05). Pre-operative values were not related to either tumour stage or serum CEA. In 20 patients with no known colorectal disease the mean faecal CEA was 5.43 +/- 1.95 micrograms/g which was significantly lower than the mean pre-operative value in the cancer patients (p less than 0.05). In 14 patients with a variety of benign colonic diseases the mean faecal CEA was 7.12 +/- 1.39 micrograms/g which was not significantly different from the mean pre-operative value in the cancer patients. Considerable overlap of values was observed between individual cancer and control patients making the test, as presently carried out, non-discriminatory. If the potential for making the test more cancer specific can be realised, however, faecal CEA determination may permit discrimination between cancer and non-cancer patients at a relatively early stage of disease.

Hepatic albumin and urea synthesis: The mathematical modelling of the dynamics of [14C]carbonate-derived guanidine-labelled arginine in the isolated perfused rat liver.

A mathematical model was constructed to define the dynamics of incorporation of radioactivity into urea carbon and the guanidine carbon of arginine in plasma albumin after the rapid intraportal-venous administration of Na214CO3 in the isolated perfused rat liver. 2. The model was formulated in terms of compartmental analysis and additional experiments were designed to provide further information on subsystem dynamics and to discriminate between alternative model structures. 3. Evidence for the rapid-time-constant of labelling of intracellular arginine was provided by precursor-product analysis of precursor [14C]carboante and product [14C]urea in the perfusate. 4. Compartmental analysis of the dynamics of newly synthesized urea was based on the fate of exogenous [13C]urea, endogenous [14C]urea and the accumulation of [12C]urea in perfusate water, confirming the early completion of urea carbon labelling, the absence of continuing synthesis of labelled urea, and the presence of a small intrahepatic urea-delay pool. 5. Analysis of the perfusate dynamics of endogenously synthesized and exogenously administered [6-14C]arginine indicated that although the capacity for extrahepatic formation of [14C]-urea exists, little or no arginine formed within the intrahepatic urea cycle was transported out of the liver. However, the presence of a rapidly turning-over intrahepatic arginine pool was confirmed. 6. On the basis of these subsystem analyses it was possible to offer feasible estimations for the parameters of the mathematical model. However, it was not possible to stimulate the form and magnitude of the dynamics of newly synthesized labelled urea and albumin which were simultaneously observed after administration of [14C]carbonate on the basis of a preliminary model which postulated that both products were derived from a single hepatic pool of [16-14C]arginine. On the other hand these observed dynamics could be satisfied to a two-compartment arginine model, which also provided an explanation for discrepancies observed between albumin synthesis measured radioisotopically and immunologically. This was based on a relative overestimation of [14C]urea specific radioactivity resulting from the rapid dynamics of [14C]carbonate and the [14C]urea subsystem relative to the labelled albumin subsystem. The effects of arginine compartmentalization could be minimized in the model by minor slowing of the rate of [14C]carbonate turnover or by constant infusion of [14C]carbonate, both of which permitted valid determination of albumin-synthesis rates.