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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Concentrations of bacteria in cerebrospinal fluid ranged from 4.5 X 10(3) to 3 X 10(8) colony-forming units/ml in 27 patients with bacterial meningitis before antibiotic therapy and from 4 X 10(1) to 1.4 X 10(6) CFU/ml in four patients after one to two days of antibiotic therapy. All patients with persistent positive cultures had pretreatment concentrations of 10(7) CFU/ml or greater. A significant association was observed between cerebrospinal fluid lactic acid dehydrogenase activity and concentrations of bacteria (p less than 0.01). Large inocula of Hemophilus influenzae type b (10(7)) increased the minimal inhibitory concentration for penicillin and ampicillin but not for chloramphenicol. The minimal inhibitory concentration of each of the three antibiotics increased when group B streptococci were assayed. These data indicate that persistence of a positive culture may be related to large initial concentrations of bacteria. The relative "resistance" in vitro of large inocula possibly contributes to this persistence. These observations are also consistent with the hypothesis that lactic acid dehydrogenase activity in cerebrospinal fluid is derived from bacteria.
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PMID:Concentrations of bacteria in cerebrospinal fluid of patients with bacterial meningitis. 0 35

To further examine the effects of purified Haemophilus influenzae type b lipopolysaccharide (LPS) on blood-brain barrier permeability, we have developed an in vitro model of the BBB. Microvascular endothelial cells were isolated from rat cerebral cortices by enzymatic digestion, dextran centrifugation, and separation on percoll gradients. The cells were determined to be endothelial in origin by positive fluorescent staining for Factor VIII-related antigen and the ability to take up acetylated low density lipoproteins, and their cerebral origin by the formation of junctional complexes in vitro. Cells were seeded onto semipermeable polycarbonate filters and permeability assessed by measuring traversal of radioactive albumin across the monolayer. Treatment of the cells with LPS at concentrations of 1.0 microgram/ml and 0.1 microgram/ml for 4 h led to statistically significant increases in albumin permeability of 4.6% (P = 0.001) and 5.6% (P less than 0.001), respectively, without evidence of cell death as assessed by release of lactate dehydrogenase into the media. These results indicate that LPS significantly increases albumin permeability across a monolayer of cerebral microvascular endothelial cells in the absence of host inflammatory cells. Future studies on the effects of LPS on intracellular regulation will determine the mechanisms responsible for these alterations.
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PMID:Blood-brain barrier alterations in bacterial meningitis: development of an in vitro model and observations on the effects of lipopolysaccharide. 182 2

The cytotoxicity of purified lipopolysaccharide (LPS) from a prototype Haemophilus influenzae type b (Hib) strain (Eagan) and three transformants, differing in their LPS phenotype, for bovine aortal endothelial cells (BAOEC) was investigated. All LPS preparations caused cell disruption and release of lactate dehydrogenase (LDH), an indicator of cytotoxicity, from BAOEC monolayers but to differing extents. There was no correlation between the cytotoxicity of purified Hib LPS to BAOEC monolayers and potential to cause bacteraemia in experimental animals.
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PMID:In vitro cytotoxicity of Haemophilus influenzae lipopolysaccharides for bovine aortal endothelial cells. 188 91

The values of some basic laboratory features on admission to hospital were recorded and compared in 418 adult patients with community-acquired pneumonia, namely erythrocyte sedimentation rate, C-reactive protein, white blood cell (WBC) count, serum lactate dehydrogenase (S-LD), serum alanine-aminotransferase, and serum sodium. Discriminant analysis was performed to obtain an aetiological diagnosis. WBC value of greater than 15 x 10(9)/l strongly indicated a bacterial and, especially a pneumococcal aetiology, whereas increased S-LD could imply a mycoplasmal infection. For patients less than 50 years of age the equation C2 = -1.788 + 0.204 x WBC-0.0909 X S-LD was constructed, in which C2 greater than 0 indicated a pneumococcal aetiology. This function correctly classified 31/33 (93.9%) patients with a mycoplasmal and 20/31 (64.5%) patients with a pneumococcal infection. Patients with viral, Haemophilus influenzae or chlamydial infection could not be discriminated from each other. The age of the patient, WBC and possibly S-LD on admission are easily accessible parameters and these results could therefore be of value in daily clinical practice in hospitals.
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PMID:Rapid aetiological diagnosis of pneumonia based on routine laboratory features. 225 62

Haemophilus influenzae D(-)-lactate dehydrogenase (D(-)-lactate:NAD oxidoreductase; EC 1.1.1.28) was purified to electrophoretic homogeneity using salt fractionation, hydrophobic and dye affinity chromatography. The enzyme was purified 2100-fold with a 14% recovery and a final specific activity of 300 units/mg protein. The enzyme was demonstrated to be a tetramer of Mr 135,000. The enzyme catalyzed the reduction of pyruvate to give exclusively D(-)-lactate using NADH as coenzyme. The reaction catalyzed was essentially unidirectional, with the oxidation of D-lactate in the presence of NAD proceeding at less than 0.2% the rate of pyruvate reduction. Kinetic parameters for the reduction of pyruvate were determined for NADH and four structural analogs of the coenzyme. Coenzyme-competitive inhibition by adenosine derivatives indicated the presence of regions in the coenzyme binding site interacting with the adenosine and pyrophosphate moieties of the coenzyme. The purified enzyme was sensitive to oxidation and was effectively inactivated by sulfhydryl reagents. Conversion of D-lactate to pyruvate catalyzed by a membrane-bound D-lactate oxidase was demonstrated in cell-free extracts of H. influenzae.
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PMID:Purification and characterization of Haemophilus influenzae D-lactate dehydrogenase. 230 73

Cytotoxic effects of bacteria found in dental plaque are usually attributed to lipopolysaccharides (LPS) or ill-defined toxins. Many bacteria implicated in periodontal disease produce surface exopolymers (capsules) recently shown to stimulate bone resorption. Capsular material and LPS extracted from Actinobacillus (Haemophilus) actinomycetemcomitans were purified and examined for their effects on cultures of human gingival fibroblasts. DNA and collagen synthesis were significantly inhibited by capsular material (0.1-50 micrograms/ml). LPS caused only modest inhibition of DNA synthesis at 10 and 50 micrograms/ml, and had no effect on collagen synthesis. Release of lactate dehydrogenase from fibroblasts was not increased by LPS nor by capsular material, showing that the inhibitory effects were not due to cell death. Capsular material, but not LPS, caused a pronounced increase in cell size; a doubling of the nuclear area occurred within 72 h exposure. These results indicate that the capsule of A. actinomycetemcomitans may play an active role in the tissue destruction characterising inflammatory periodontal disease.
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PMID:Inhibition of fibroblast proliferation and collagen synthesis by capsular material from Actinobacillus actinomycetemcomitans. 377 77

Microorganisms encountered in cerebrospinal fluid require rapid and accurate means of detection and identification in the laboratory. Although restricted to morphologic study and Gram reaction, the Gram stain of cerebrospinal fluid has been the primary diagnostic tool for preliminary diagnosis of purulent meningitis, with identification of the etiologic agent often made within one to two hours by direct microscopic examination. Gram stain and appropriate culture procedures still provide the basis for comparing other diagnostic methods. Nonimmunologic methods that show promise in being both rapid and reliable include gas-liquid chromatography and the Limulus amebocyte lysate test. Fatty acid and carbohydrate profiles characteristic of Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitidis, and Staphylococcus aureus in the cerebrospinal fluid of human subjects and animals have been obtained by gas-liquid chromatography. Also, a unique compound has been detected by gas-liquid chromatography in cerebrospinal fluid from patients with tuberculous meningitis. The Limulus test has been reliable in spinal fluid and almost always gives positive results in H. influenzae and other Gram-negative meningitides. Nonspecific test procedures of varying degrees of accuracy and promise include lactic acid, C-reactive protein, and lactate dehydrogenase determination. Direct microscopic examination of cerebrospinal fluid remains the most practical and accurate method for identifying the etiologic basis of bacterial (and fungal) meningitis.
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PMID:Rapid and reliable techniques for the laboratory detection of bacterial meningitis. 634 38

We evaluated the effectiveness of 5-day antibacterial therapy for bacterial meningitis in children. The study group included 26 children from 2 months to 15 years of age, admitted with microbiologically confirmed bacterial meningitis in 1990-1993 and treated for 5 days. A historical comparison group of 49 patients treated for 8 to 15 days was used. Penicillin monotherapy (300 mg/kg body weight) was used for meningococcal and pneumococcal meningitis and ampicillin (300 mg/kg body weight) for Haemophilus influenzae b meningitis. On day 5 of therapy the activity of aspartate aminotransferase (AST), lactic dehydrogenase (LDH), creatine phosphokinase (CPK) and gamma-glutamyl-transpeptidase (gamma GT) in the CSF was determined by photocolorimetric assay and the concentration of creatine kinase BB (CK-BB) by ELISA. IL-6 was analysed using EIA technique and a cerebral ultrasound was performed at the time of the termination of the antibacterial therapy. The mean follow-up time was 1.3 years for children in the study group and 3.2 in the control group. The time of hospitalisation was shorter in children treated for 5 days (p < 0.005). Complete clinical recovery was 81% in the study group and 66% in the comparison group at the time of the termination of antibacterial therapy. No relapses occurred. The activity of AST, CPK, LDH, and gamma GT in the CSF had returned to normal by the 5th day of therapy, but almost a 7-fold higher concentration of CK-BB was registered. The concentration of IL-6 in the CSF decreased with the therapy from 1,800 pg/ml to 685 pg/ml but still remained high.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Five days of antibacterial therapy for bacterial meningitis in children? 762 59

Toxins that slow ciliary beat are virulence determinants of bacteria that infect or invade ciliated epithelial surfaces. We have previously shown that the effect of the Pseudomonas aeruginosa toxin pyocyanin on ciliary beat is associated with a fall in intracellular cAMP and ATP. We have now investigated whether reduction in intracellular adenosine nucleotides might be a common mechanism of action of other bacterial toxins which slow ciliary beat. Two other P. aeruginosa toxins, 1-hydroxyphenazine (1-HP) and rhamnolipid, and two Haemophilus influenzae fractions produced by gel filtration of broth cultures were tested. The effect on human nasal epithelium ciliary beat frequency (CBF), and intracellular cAMP and ATP were measured, and the effect of two pharmacological agents, dibutyryl cAMP and salmeterol, on these changes was assessed. 1-HP, rhamnolipid and the two H. influenzae fractions slowed CBF before there was significant release of lactate dehydrogenase from the cells. The toxins also caused a fall in intracellular cAMP and ATP. Dibutyryl cAMP and salmeterol at the concentrations used do not increase baseline CBF, but diminished the fall in CBF and intracellular adenosine nucleotides. The cAMP and ATP levels in these studies were combined with those previously obtained with pyocyanin. there was a good correlation between cAMP and ATP levels and CBF. Bacterial toxins which slow CBF may act by causing a fall in intracellular adenosine nucleotides, and agents which stimulate cAMP may prevent toxin-induced slowing of ciliary beat.
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PMID:The effect of bacterial toxins on levels of intracellular adenosine nucleotides and human ciliary beat frequency. 916 Apr 10

Cell surface-associated materials of Actinobacillus actinomycetemcomitans were extracted by a short incubation of the cell suspension in a Tris-buffered saline in the presence and absence of a restriction enzyme, EcoRI. The supernatants (which we termed EcoRI extract and surface extract, respectively) contained a number of extracellularly released proteins. Of these proteins, four major proteins were identified by N-terminal sequencing to be the 34 and 39 kDa outer membrane proteins, the GroEL-like protein, and a 47 kDa protein homologous to Haemophilus influenzae enolase. Enolase activity was found in the extracts and its relative amount of activity in the EcoRI extract from a culture of the mid-exponential growth phase was estimated as 5.7% of total enzyme activity. In contrast, the relative amount of activity of another cytosolic enzyme, lactate dehydrogenase, was extremely low in the extracts and also in the culture supernatant. These results suggest the external localization of enolase in this bacterium.
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PMID:Cell surface-associated enolase in Actinobacillus actinomycetemcomitans. 1088 52


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