Empowering the clinical nurse through quality assurance in a shared governance setting.
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Decision Making, Organizational↗
Biomedical subjects
L Daniels
Publications and source records attributed to L Daniels.
Biotechnological potential of methanogens.
Methane produced microbiologically is currently used as an energy source, especially by cities and industries, albeit at a level far below its potential; the incentive is currently to save money on disposal costs for waste problems. Anaerobic digestion can be helpful in degrading several halogenated hydrocarbon wastes, and methanogens are partly responsible. Ethane instead of methane may be a future product of interest. Some pure cultures of methanogens may be suitable for production of B-12, or perhaps the speciality biochemical F420, a 5-deazaflavin of interest to both methanogen and streptomyces researchers. Methanogens can cause a variety of problems, including biocorrosion, increased atmospheric methane, and ruminant nutrition loss. Studies of tropical wetlands, including rice paddies and swamps, and the study of a variety of ruminants in the tropics are particularly interesting and appropriate at this time, with respect to methane produced in these ecosystems. In some cases, it may be possible to control methane production by the use of inhibitors or ecological control mechanisms.
Euryarchaeota↗
Prognostic significance of anticentromere antibodies and anti-topoisomerase I antibodies in Raynaud's disease. A prospective study.
Seventy-seven patients with Raynaud's disease were studied for a mean of 4 years (range 1-11 years) to determine the relationship between autoantibodies and long-term clinical outcome. Anticentromere antibodies (ACA) were assayed by indirect immunofluorescence and by immunoblotting of HeLa cell chromosome extracts. Antibodies to topoisomerase I (anti-topo I) were assayed by immunodiffusion and immunoblotting. Antibodies to the major centromeric protein, CENP-B, and anti-topo I were studied by enzyme-linked immunosorbent assay (ELISA). Eight patients developed telangiectasias, 4 developed skin tightening, and 4 developed a connective tissue disease other than scleroderma. The presence of ACA at the start of the study was associated with the development of telangiectasias (P less than 0.003). An initial 100-kd band on immunoblot in conjunction with a positive anti-topo I ELISA result was associated with the development of tight skin (P less than 0.0025), while a 100-kd band with a negative anti-topo I ELISA result was associated with the subsequent development of a connective tissue disease other than scleroderma (P less than 0.0073). Patients who were initially ACA positive, had the 100-kd band on immunoblot, or had positive ELISA results for anti-topo I or for anti-CENP-B were 63-fold more likely to develop signs of connective tissue disease by the end of the study (P less than 0.000009). The presence of any of these autoantibodies was more sensitive (100%), although less specific (75%), than were findings from nailfold capillaroscopy (sensitivity 67% and specificity 95%) in predicting subsequent clinical progression. We conclude that findings of assays for anti-topo I and ACA complement the findings from nailfold capillaroscopy in providing useful prognostic information in Raynaud's disease.
Antibodies↗
Pattern of organotin inhibition of methanogenic bacteria.
Seven organotin compounds and tin chloride were tested for their effects on the methanogenic bacteria Methanococcus thermolithotrophicus, Methanococcus deltae delta LH, and Methanosarcina barkeri 227. The methanogens were strongly inhibited by triethyltin, tripropyltin, and monophenyltin compounds, generally at concentrations below 0.05 mM. Less inhibition by tributyltin and diphenyltin was observed at levels below 0.1 mM, but complete inhibition was observed at a 1 mM concentration. Tin chloride inhibited all methanogens, with nearly complete inhibition at a 1 mM concentration. There was no inhibition by tetra-n-butyltin and triphenyltin compounds even at 2 mM, the highest concentration tested. The 50 and 100% inhibitory concentrations of all compounds were estimated; these values varied with both the compound tested and the bacterium tested. The 50% inhibitory concentration estimate generally decreased (i.e., giving a higher toxicity) as the total surface area of the alkyltin molecules decreased. These results differ considerably from those reported previously for aerobic microorganisms (G. Eng, E. J. Tierney, J. M. Bellama, and F. E. Brinckman, Appl. Organometallic Chem. 2:171-175, 1988), where a clear correlation between increasing total molecular surface area and increasing toxicity was documented with a variety of organisms. Using the same procedures as for the methanogens, we examined the effects of organotin compounds on Escherichia coli growing aerobically or anaerobically. The E. coli inhibition pattern clearly resembled that seen in the data of Eng et al., under both aerobic and anaerobic conditions.
Escherichia coli↗
Effect of pH on Anaerobic Mild Steel Corrosion by Methanogenic Bacteria.
Methanogens can use H(2) produced by cathodic depolarization-mediated oxidation of elemental iron to produce methane. Thermodynamic consideration of the cathodic depolarization mechanism predicts more oxidation of Fe at lower pH. Methanogenic responses to pH by Methanococcus deltae, Methanococcus thermolithotrophicus, and Methanosarcina barkeri were examined. When grown on H(2)-CO(2), these bacteria had pH optima from 6.2 to 7.0, but when all H(2) was supplied from Fe, methanogenic pH optima were lower, 5.4 to 6.5. Corrosion was monitored with and without cultures and at various pHs; more corrosion occurred when cultures were present, biologically induced corrosion was greatest at the pH optima for methanogenesis from Fe, and corrosion without cultures increased with a drop in pH.
Journal Article↗
The IgG, IgM, and IgA isotypes of anti-topoisomerase I and anticentromere autoantibodies.
We studied the expression of IgG, IgM, and IgA autoantibodies in the anti-topoisomerase I and anticentromere immune responses by enzyme-linked immunosorbent assay, immunoblotting, and immunofluorescence. While IgG autoantibodies were most common, IgA autoantibodies were also frequently found, but IgM autoantibodies were rare. This is the first report of IgA autoantibodies in scleroderma.
Autoantibodies↗
Elemental metals as electron sources for biological methane formation from CO2.
Several elemental metals were examined as potential electron donors for methanogenic bacteria, using both a single tube system where the metal was in direct contact with the cells, and a two-flask system, where metal and cells were not in direct contact, but had contact via the gas phase. With all organisms examined in the direct contact system, Fe degree, Al degree and Zn degree served as electron donors for methanogenesis; some organisms used Ni degree or Sn degree as low-level electron donors. Of the metals tested, methanogenesis from H2 + CO2 was inhibited by direct contact with Zn degree or Cu degree, but not by Fe degree or Al degree. Ni degree and Co degree were inhibitory to some methanogens, with Ni degree being particularly inhibitory to the thermophilic strains tested. With all organisms examined in the two-flask system, Fe degree and Zn degree served as good electron sources for both methanogenesis and growth; Co degree generated a very low level of methane and Cu degree did not work at all. In either system V degree, Ti degree or Cd degree did not serve as electron donors. The results suggest that some elemental metals (notably Fe degree, Al degree and Zn degree) produce gaseous H2 by cathodic depolarization which is then consumed by the methanogen, thus accelerating oxidation of the metal by its metabolic activity. All of these reactions are thermodynamically favorable; however, some other metals that are clearly favorable for such a reaction on thermodynamic grounds (Ti degree and V degree) are very stable and do not serve as electron donors.
Aluminum↗
Evaluation of long-term aggressive dietary management of chronic renal failure in children.
Ten children with chronic renal failure (CRF) were managed for 3 years using a strict low-protein and low-phosphorus diet supplemented by a mixture of the keto and amino forms of the essential amino acids and histidine (phase II). All of these children were previously managed for at least 2 years with a less rigorous diet of limited protein intake with no specific reduction of phosphorus (phase I). Energy, vitamin D, bicarbonate, phosphate binders and vitamin and mineral mixtures were added as required during both dietary phases. Data on dietary intake showed a significant fall in protein and phosphorus intake and a rise in calcium intake during phase II compared with phase I. Plasma calcium increased and phosphate fell, with an associated fall in intact parathyroid hormone levels. There was a marked improvement in urea creatinine ratios, which suggested an improved anabolic state. Cholesterol and triglyceride levels were improved. Height and weight velocity were increased, becoming significant after 3 years of phase II. Renal function deteriorated at a slower rate than predicted. The diet was well tolerated by the children, with fitness and school performance showing improvement. We conclude that long-term strict dietary management of children with CRF is feasible. Our data suggest an overall improvement in general health and an apparent reduction in the rate of deterioration of renal function.
Adolescent↗
Thiosulfate, polythionates and elemental sulfur assimilation and reduction in the bacterial world.
Among sulfur compounds, thiosulfate and polythionates are present at least transiently in many environments. These compounds have a similar chemical structure and their metabolism appears closely related. They are commonly used as energy sources for photoautotrophic or chemolithotrophic microorganisms, but their assimilation has been seldom studied and their importance in bacterial physiology is not well understood. Almost all bacterial strains are able to cleave these compounds since they possess thiosulfate sulfur transferase, thiosulfate reductase or S-sulfocysteine synthase activities. However, the role of these enzymes in the assimilation of thiosulfate or polythionates has not always been clearly established. Elemental sulfur is, on the contrary, very common in the environment. It is an energy source for sulfur-reducing eubacteria and archaebacteria and many sulfur-oxidizing archaebacteria. A phenomenon still not well understood is the 'excessive assimilatory sulfur metabolism' as observed in methanogens which perform a sulfur reduction which exceeds their anabolic needs without any apparent benefit. In heterotrophs, assimilation of elemental sulfur is seldom described and it is uncertain whether this process actually has a physiological significance. Thus, reduction of thiosulfate and elemental sulfur is a common but incompletely understood feature among bacteria. These activities could give bacteria a selective advantage, but further investigations are needed to clarify this possibility. Presence of thiosulfate, polythionates and sulfur reductase activities does not imply obligatorily that these activities play a role in thiosulfate, polythionates or sulfur assimilation as these compounds could be merely intermediates in bacterial metabolism. The possibility also exists that the assimilation of these sulfur compounds is just a side effect of an enzymatic activity with a completely different function. As long as these questions remain unanswered, our understanding of sulfur and thiosulfate metabolism will remain incomplete.
Archaea↗
Regulation of formate dehydrogenase activity in Methanococcus thermolithotrophicus.
Methanococcus thermolithotrophicus can use either H2 or formate as the electron donor for methanogenesis from CO2. Resuspended-cell experiments revealed that the ability to use H2 as the source of electrons for methanogenesis was constitutive; cells grown on formate or H2-CO2 were equally capable of H2-CO2 methanogenesis. The ability to metabolize formate at high rates was observed only in cells previously grown on formate. Two such strains were distinguished: strain F and strain HF. Strain F was repeatedly grown exclusively on formate for over 3 years; this strain showed a constitutive capacity to metabolize formate to methane, even after subsequent repeated transfers to medium containing only H2-CO2. Strain HF could only metabolize formate to methane when grown in the presence of formate with no H2 present; this strain was recently derived from another strain (H) that had been exclusively grown on H2-CO2 and which upon initial transfer to formate medium could only metabolize formate to methane at a very slow rate. Initial adaptation of strain H to growth on formate was preceded by a long lag. The specific activities of hydrogenase and formate dehydrogenase in cell extracts derived from these different strains confirmed these findings. Similar levels of hydrogenase were observed in all strains, independent of the presence of H2 in the growth medium medium. High levels of formate dehydrogenase were also constitutive in strain F. Only low formate dehydrogenase activities were observed in strain H. High levels of formate dehydrogenase were observed in strain HF only when these cells were grown with formate in the absence of H2. In all strains the two- to threefold fluctuations of both hydrogenase and formate dehydrogenase cell-free activities were observed during growth, with peak activities reached in the middle of the exponential phase.
Aldehyde Oxidoreductases↗
Methanogenic bacteria in human vaginal samples.
Twelve vaginal samples were collected from separate patients, processed anaerobically, and added to methanogenic enrichment medium. Methanogenic activity was detected in two samples, both of which were from patients with bacterial vaginosis. None of the samples from healthy patients yielded positive methanogen cultures. One sample from a patient with bacterial vaginosis did not show any detectable methanogenic activity. Two methanogen isolates were obtained from one of the methanogen-positive samples, and both were identified as Methanobrevibacter smithii on the basis of morphological, cultural, and immunological features.
Bacterial Infections↗
Road to recovery.
The role of the nurse in giving information to patients has grown considerably following the work of researchers such as Hayward (1975), Boore (1978) and Wilson-Barnett (1978). From admission to discharge the nurse has a valuable educational role to play in helping patients come to terms with their present position and preparing them for the future. The questions facing nursing now are not whether nurses should undertake this role, but how well do they provide information? Do patients act on advice? And how far should relatives be included in the process of patient education? These are the questions that prompted the present study, in which 43 people completed questionnaires 6 to 8 weeks following discharge from hospital after cardiac surgery. Eighty-two per cent were completely or 'on the whole' satisfied with the information given, though the perceived adequacy varied between topics; 70% reported some associated behaviour change and in each case their relatives had been involved in receiving pre-discharge advice.
Aged↗
Supplemental nasogastric feeding in cystic fibrosis patients during treatment for acute exacerbation of chest disease.
The use of overnight, nasogastric, nutritional supplementation during hospitalization of children with cystic fibrosis (CF) receiving antibiotic therapy for acute exacerbations of respiratory disease was evaluated in 11 children (mean age = 7.75 years). Supplementary feeding significantly increased inpatient energy intake from 116 +/- 30% to 165 +/- 30% (P less than 0.001) of recommended dietary allowance with minimal effect on oral intake. It also resulted in significantly improved weight gains but neither increased energy intakes nor weights were sustained at short-term (mean = 5.7 weeks) or long-term (mean = 21.6 weeks) follow-up. The notion that short bursts of nasogastric feeding for inpatients with CF improve growth status is not supported. However, the study did show that treatment of chest infections alone does not positively affect spontaneous oral energy intake.
Adolescent↗
Aerobic purification of N5,N10-methylenetetrahydromethanopterin dehydrogenase, separated from N5,N10-methylenetetrahydromethanopterin cyclohydrolase, from Methanobacterium thermoautotrophicum strain Marburg.
The N5,N10-methylenetetrahydromethanopterin dehydrogenase from Methanobacterium thermoautotrophicum strain Marburg has been purified with reasonable yield and much higher specific activity than previously reported. For the first time it has been shown that both N5,N10-methylenetetrahydromethanopterin dehydrogenase and N5,N10-methenyltetrahydromethanopterin cyclohydrolase activities were stable under air and could be purified using aerobic operations. The dehydrogenase activity from Methanobacterium thermoautotrophicum Marburg was stable in phosphate buffer with or without glycerol or ammonium sulfate under both aerobic and anaerobic conditions. However, the presence of either 2-mercaptoethanol or dithiothreitol in the enzyme solution destroyed the enzyme activity during both aerobic and anaerobic incubations. Dehydrogenase was purified 62-fold using Phenyl-Sepharose and DEAE-Sephadex chromatography in succession under air. Both of these chromatographic methods separated dehydrogenase activity from N5,N10-methenyltetrahydromethanopterin cyclohydrolase; DEAE-Sephadex provided the best separation. Phenyl-Sepharose chromatography of the supernatant of cell extracts containing ammonium sulfate at 60% of saturation provided a 4.7-fold purification and 98% recovery of cyclohydrolase; this result established the air stability of N5,N10-methenyltetrahydromethanopterin cyclohydrolase from Methanobacterium thermoautotrophicum Marburg.
Aerobiosis↗
Wernicke's encephalopathy in an 18-year-old woman.
An unusually young woman (18 years old) who misused alcohol and developed Wernicke's encephalopathy is described.
Adolescent↗
Physiological and 15N-NMR analysis of molecular nitrogen fixation by Methanococcus thermolithotrophicus, Methanobacterium bryantii and Methanospirillum hungatei.
Two mesophilic methanogenic bacteria, Methanobacterium bryantii strain MOH and Methanospirillum hungatei strain GP1 were demonstrated, using several different experimental approaches, to fix dinitrogen. Evidence includes (1) growth with N2 as the sole nitrogen source; (2) incorporation of 15N2 into cellular material (both soluble amino acid pools and insoluble cell protein and other macromolecules) detected by 15N-NMR spectroscopy; (3) acetylene reduction to ethylene by the cells, and inhibition of this reaction by bromoethanesulfonic acid (BES), a methanogen inhibitor. High-resolution 15N-NMR analysis of ethanol extracts of these organisms and cross-polarization magic-angle sample spinning analysis of the solid debris from these extracts are compared to labeled material from Methanococcus thermolithotrophicus, a methanogen previously determined to fix dinitrogen.
Clostridium↗
Ethane production by Methanosarcina barkeri during growth in ethanol supplemented medium.
Methanosarcina barkeri strain 227 produced ethane during growth on H2/CO2 when ethanol was added to the medium in concentrations of 89-974 mM; ethane production varied from 14 to 38 nmoles per tube (20 ml gas phase, 5.7 ml liquid) with increasing ethanol concentrations. Cells grown to mid-logarithmic phase (A600 approximately 0.46, protein = 64 micrograms/ml) on H2/CO2, thoroughly flushed with H2/CO2, then exposed to ethanol, produced maximal ethane levels (at 585 and 974 mM ethanol) of about 215 nmoles per tube, with an ethane/methane ratio of 1 x 10(-3). Mid-logarithmic-phase cultures of Methanosarcina barkeri strain Fusaro also produced ethane (up to 20 nmoles per tube) when exposed to ethanol. Cultures of strain 227 growing on methanol in the absence of H2 produced less than or equal to 6 nmoles per tube of ethane when supplemented with ethanol whereas those lacking ethanol but containing H2 and/or methanol produced less than or equal to 1.6 nmoles per tube. Cultures of Methanococcus deltae strains delta LH and delta RC, Methanospirillum hungatei or Methanobacterium thermoautotrophicum produced less than or equal to 5 nmoles ethane per tube when grown in medium containing ethanol. Ethanol concentrations of 177-886 mM were inhibitory to growth of all methanogens examined. Production of ethane by Methanosarcina was inhibited by greater than 62 mM methanol, and both methanogenic inhibitors tested, CCl4 and Br-CH2-CH2-SO3-, inhibited ethane and methane production concurrently. The data suggest that ethanol is converted to ethane by Methanosarcina species using the terminal portion of the methanol-to-methane pathway.
Anaerobiosis↗
Methanogenic bacteria from human dental plaque.
Samples of human dental plaque were examined for the presence of methanogenic bacteria. Of 54 samples from 36 patients, 20 yielded H2/CO2-using methanogenic enrichment cultures. All methanogen-positive samples were from patients with some degree of periodontal disease. The predominant populations in the enrichments had morphologies characteristic of Methanobrevibacter spp. In six enrichments derived from three patients, the common methanogen was antigenically similar to Methanobrevibacter smithii. The same was true for the three methanogenic isolates obtained in axenic culture from a fourth patient. The six enrichments and two of the three isolates were antigenically closer to strain ALI than to PS. Two of the enrichments also had subpopulations with weak antigenic similarity to Methanosphaera stadtmanae. The data indicate that methanogens in the oral cavity of humans are antigenically close to those found in the intestinal tract.
Antigens, Bacterial↗