Traditional methods for quantifying specific catabolic bacterial populations underestimate the true population count due to the limitations of the necessary laboratory cultivation methods. Likewise, in situ activity is also difficult to assess in the laboratory without altering the sample environment. To circumvent these problems and achieve a true in situ bacterial population count and activity measurement, new methods based on molecular biological analysis of bacterial nucleic acids were applied to soils heavily contaminated with polycyclic aromatic hydrocarbons (PAH). In addition, a naphthalene-lux reporter system was used to determine bioavailability of naphthalene within these soils. DNA extracted from seven PAH-contaminated soils and hybridized with the nahA gene probe indicated that the naphthalene degradative genes were present in all samples in the range of 0.06 to 0.95 ng/100 microliters DNA extract which was calculated to represent 3.2 x 10(6) to 1.1 x 10(10) cells/g soil (assuming one copy of these genes per cell). 14C-naphthalene mineralization was observed in all contaminated soils with 14CO2 mineralization rates ranging from 3.2 x 10(-5) to 304,920.0 x 10(-5) micrograms g soil-1 h-1. Phenanthrene, anthracene, and benzo(a)pyrene were mineralized also in several soils. Messenger RNA transcripts of nahA were isolated and quantified from 4 soils. Only one soil tested, soil B, was inducible with salicylate above the in situ nahA gene transcript level. Two of the soils, C and G, were already fully induced in situ. The naphthalene mineralization rate correlated positively with the amount of nahA gene transcripts present (r = 0.99). Naphthalene was bioavailable in soils A, D, E, G, and N as determined by a bioluminescent response from the naphthalene-lux reporter system. Taken together, these data provided information on what the naphthalene-degrading bacterial population was experiencing in situ and what approaches would be necessary to increase activity.

Bacteria↗

PubMedDate not supplied

Impaired beta-adrenergic control of immune function in patients with chronic heart failure: reversal by beta1-blocker treatment.

BACKGROUND: In patients with chronic heart failure (CHF) and heightened sympathetic activity alterations in immune function have been described. OBJECTIVES: To find out whether, in CHF patients, beta-blocker treatment might beneficially affect immune function. METHODS: We studied activation of circulating lymphocytes (assessed as concanavalin A (CON A)-induced inositol phosphate (IP) formation and proliferation ([3H]-thymidine incorporation) from 8 CHF patients on standard medication (Group A, mean age 54 +/- 6 yrs, NYHA class II - IV, mean 3.1 +/- 0.3) and in 9 CHF patients on standard medication and additional treatment with the beta1-blocker metoprolol (Group B, mean age: 56 +/- 3 yrs, NYHA class II - IV, mean 2.9 +/- 0.2); 8 age-matched healthy volunteers (mean age 49 +/- 3 yrs) served as controls. RESULTS: Compared to controls, in group A isoprenaline-induced lymphocyte cyclic AMP-increase was reduced, CON A-evoked IP formation significantly enhanced and isoprenaline-induced inhibition of CON A-evoked IP formation and proliferation almost abolished. In group B, however, all these parameters were not significantly different from controls. CONCLUSION: In CHF patients lymphocyte cyclic AMP response to beta-adrenoceptor stimulation is blunted and the inhibitory effect of cyclic AMP on lymphocyte activation is almost abolished; this could result in a non-regulated increased production and release of proinflammatory cytokines that might contribute to the progression of the disease. Chronic treatment of CHF patients with the beta1-blocker metoprolol (at least partly) restores lymphocyte cyclic AMP responses to beta-adrenoceptor stimulation and the inhibitory effects of cyclic AMP on lymphocyte activation; the resulting "normalization" of the immune function might contribute to the beneficial effects of beta1-blockers in treatment of CHF.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

The laryngeal mask airway: anesthetic gas leakage and fiberoptic control of positioning.

STUDY OBJECTIVE: To examine the anesthetic gas leakage and prelaryngeal position of the laryngeal mask airway (LMA). DESIGN: Clinical trial evaluating LMA ventilation conditions. SETTING: Lithotripsy room of a urology clinic at a university hospital. PATIENTS: 100 adult ASA physical status I and II patients undergoing general anesthesia for kidney stone lithotripsy. INTERVENTIONS: Anesthesia was induced with propofol 1.5 to 2.5 mg/kg intravenously (IV) and fentanyl 1 to 1.5 micrograms/kg IV and maintained with isoflurane plus nitrous oxide in oxygen. MEASUREMENTS AND MAIN RESULTS: Waste anesthetic gas concentration, an indicator of mask tightness during intermittent positive-pressure ventilation, was measured using an infrared oxide analyzer. LMA position in relation to laryngeal skeleton was assessed using fiberoptic laryngoscopy. The LMA was found to be gastight in 62% of patients, with a peak airway pressure up to 25 cmH2O. During peak airway pressure ventilation less than 10 cmH2O and during spontaneous ventilation, waste anesthetic gas contamination in the anesthesiologist's breathing zone was within legal limits in every case. During peak airway pressure ventilation up to 30 cmH2O, contamination was found within legal limits in 78% of all cases. Fiberoptic control showed a central position in 59% of cases, lateral deviations to the left or right in 29%, dorsal positions in 8%, and ventral positions in 4%. Incorrect ventral or dorsal positioning was related to forced reclining or forced flexion of the patient's head. There was no correlation between LMA position and tightness. The esophageal entrance was visible in 15 patients using high peak airway pressure greater than 25 cmH2O. CONCLUSIONS: The LMA is a new airway management technique with good qualities of tightness and ventilation conditions. However, contraindications such as patients with a full stomach, intra-abdominal surgery, high peak airway pressure, prolonged operation, and an inexperienced anesthesiologist apply.

Adult↗

PubMedDate not supplied

Supplementation with dietary fiber improves fecal incontinence.

BACKGROUND: Human studies have shown that dietary fiber affects stool composition and consistency. Because fecal incontinence has been shown to be exacerbated by liquid stools or diarrhea, management strategies that make stool consistency less loose or liquid may be useful. OBJECTIVE: To compare the effects of a fiber supplement containing psyllium, gum arabic, or a placebo in community-living adults who were incontinent of loose or liquid stools. Mechanisms underlying these effects (e.g., fermentation of the fibers and water-holding capacity of stools) were examined. METHODS: Thirty-nine persons with fecal incontinence of loose or liquid stools prospectively recorded diet intake and stool characteristics and collected their stools for 8 days prior to and at the end of a 31-day fiber supplementation period. During the fiber supplementation period, they ingested psyllium, gum arabic, or a placebo by random assignment. RESULTS: In the baseline period, the groups were comparable on all variables measured. In the fiber supplementation period, (a) the proportion of incontinent stools of the groups ingesting the fiber supplements was less than half that of the group ingesting the placebo, (b) the placebo group had the greatest percentage of stools that were loose/unformed or liquid, and (c) the psyllium group had the highest water-holding capacity of water-insoluble solids and total water-holding capacity. The supplements of dietary fiber appeared to be completely fermented by the subjects as indicated by nonsignificant differences in total fiber, short chain fatty acids and pH in stools among the groups in the baseline or fiber supplementation periods. CONCLUSIONS: Supplementation with dietary fiber from psyllium or gum arabic was associated with a decrease in the percentage of incontinent stools and an improvement of stool consistency. Improvements in fecal incontinence or stool consistency did not appear to be related to unfermented dietary fiber.

Adult↗