Comparative studies of two ferredoxins from Desulfovibrio desulfuricans norway.

Two ferredoxins isolated from Desulfovibrio desulfuricans Norway have been purified and characterized. The less acidic, designated as ferredoxin I, contains four iron atoms, four acid-labile sulfur groups and six cysteine residues per molecule. Ferredoxin II is more acidic and abundant than ferredoxin I, but is very unstable to O2. Ferredoxin I and ferredoxin II differ according to amino acid composition but are homologous with respect to their N-terminal amino acid sequence. The absorption spectra of the two ferredoxins are similar to those of other Desulfovibrio species. Both proteins appear to be dimers of identical 6000-dalton subunits. Their activity was tested in two types of reaction in the electron transfer chain (phosphoroclastic reaction and sulfite reductase activity). The isolation of two different ferredoxins from the same organism, Desulfovibrio, has been reported in Desulfovibrio africanus but the significance of two ferredoxins functioning in the same electron transfer chain is not yet understood.

Familial restless legs with periodic movements in sleep: electrophysiologic, biochemical, and pharmacologic study.

Restless legs syndrome was present in nine members of a family over a span of five generations. In three subjects, the diagnosis was confirmed by all-night sleep recordings and concomitant EMG. Two of these three subjects also had periodic movements in sleep. The frequency of leg movements decreased from wakefulness to stages 1 and 2 non-REM sleep. There was an increase of free dopamine and homovanillic acid in CSF of the propositus. Clonazepam effectively controlled restless legs in the propositus and his mother.

Electron transfer mechanism and interaction studies between cytochrome C3 and ferredoxin.

Ferredoxin, cytochrome c3 and hydrogenase are specific partners of the sulfate reduction pathway of Desulfovibrio desulfuricans Norway and might be exemplary for electron exchange mechanism studies. Cytochrome c3 contains four low redox potential haems for 13 000 molecular weight. Two ferredoxins isolated from the same bacteria are dimers of 6 000 molecular weight per subunit (Ferredoxin I: one (4 Fe-4S) cluster per subunit, ferredoxin II: two (4 Fe-4 S) clusters per subunit). The amino acid sequence of ferredoxin I is reported and compared to the ferredoxin II sequence. The structural characteristics of ferredoxins and cytochrome c3 should allow a discussion on the nature of the interaction. 1H-NMR spectra of ferredoxin I and cytochrome c3 in the absence and presence of ferredoxin are presented.

Isolation, amino acid analysis and N-terminal sequence determination of the two subunits of the nickel-containing hydrogenase of Desulfovibrio gigas.

The two subunits of the nickel-iron hydrogenase from Desulfovibrio gigas have been purified by preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis and their amino acid compositions have been determined. The N-terminal sequences for 15 residues of the large subunit (Mr 62,000) and 25 residues of the small subunit (Mr 26,000), respectively, were established. The occurrence of several cysteine residues in the small subunit is discussed in relation with their possible role in the binding of the redox centers of the enzyme.

Primary structure of the two (4 Fe-4 S) clusters ferredoxin from Desulfovibrio desulfuricans (strain Norway 4).

The primary structure of a ferredoxin isolated from D. desulfuricans Norway strain, which we called ferredoxin II (Fd II) has been elucidated. This ferredoxin is a dimer constituted of two identical subunits of molecular weight 6000. In ferredoxin II two (4 Fe-4 S) centers are present per subunit instead of one (Fe-S) center as is the case for the other ferredoxins isolated from Desulfovibrio and for Fd I from the same organism. The comparison of amino-acid sequences shows that ferredoxin II presents more homologies with clostridial type ferredoxin than with the ferredoxins from D. gigas and D. africanus.

Interhemispheric EEG coherence before and after partial callosotomy.

Measures of interhemispheric EEG coherence during REM and NREM sleep reflect the functional connectivity of the right and left hemispheres mediated by the corpus callosum. Surface recordings of interhemispheric coherence in two patients reflected fairly accurately the degree of anatomical section produced by partial callosotomy. With further development, EEG coherence may prove useful as a noninvasive method for assessing interhemispheric integration under different physiological and experimental conditions.

Lithium carbonate and leukocytosis.

White blood cell (WBC) counts of 37 hospitalized adult psychiatric patients were examined for changes during treatment with lithium carbonate. Group 1 (n = 19) patients had WBC counts taken before and after lithium therapy. Group 2 (n = 16) patients had WBC counts taken only after lithium therapy. The remaining two patients had infections and were considered separately. In Group 1, a significant leukocytosis was observed over baseline values (p less than 0.001). The mean increase in WBC count was 2,237 cells/cu mm. For Group 2 patients, the mean WBC count observed was 11,950 +/- 4,028 cells/cu mm, which is higher than the normal leukocyte count in peripheral blood. An increase in circulating leukocytes was observed in the majority of these patients. The data indicate that the leukocytosis was drug related, but the increase did not appear to be dose related or dependent on the concentration of lithium in the blood.

[The physician and disability certificates: preconceived attitudes and behaviors]. / Le médecin face aux certificats d'invalidité: attitudes et comportements préconisés.

Five attitudes and predicted behaviors characterize the physicians' responses (strategies) to invalidity certificates. These are: 1- scientific objectivation; 2- complicity (meaning: always completing the certificates without objective preoccupations of any kind); 3- socio political (meaning: influenced by the physician's ideas concerning ways the society should consider the non-working people: permissive or repressive); 4- negotiation (implicating a psychobiosocial approach to the patient and the problem); 5- indifference (never completing certificates, referring this role to someone else). Our recent survey (September 1986) including 92 physicians of a General Hospital (Cité de la Santé) in Laval demonstrates a preponderant attitude, the "socio political" one (A3). But, it has no relation to the preponderant predicted behavior which is the negotiation (C4), characterizing a psychobiosocial approach to the patient and the problem. This behavior has been chosen in a statistically significant way. Nevertheless, there is a relation between the attitude A1: scientific objectivation and the corresponding predicted behavior C1: scientific objectivation. Notions of rationability, professionalism and sociable desirability are evoked as explanations of these results.

Effect of magnesium citrate on the in vitro adsorption of aspirin by activated charcoal.

The objective of this study was to determine if magnesium citrate solution given concurrently with activated charcoal would affect charcoal's in vitro ability to bind aspirin. Aspirin and charcoal were mixed in simulated gastric fluid and simulated intestinal fluid, and then magnesium citrate solution was added in proportions simulating those encountered clinically. Results indicate that no clinically significant interaction occurs between magnesium citrate and activated charcoal in either fluid, and that these two agents can be given simultaneously without decreasing the binding capacity for aspirin.

[Prophylaxis of gastroduodenal hemorrhage caused by stress during pediatric intensive care]. / Prophylaxie des hémorragies gastroduodénales de stress acquises en soins intensifs pédiatriques.

Patients admitted to intensive care units frequently develop stress ulcers, erosive gastritis and complications such as upper gastrointestinal bleeding. Stress-related upper gastrointestinal bleeding (UGIB) has been of particular concern to many practitioners working in intensive care units and has led to the treatment of most if not all patients admitted to these units with antacids, H2 receptor antagonists or sucralfate in order to protect the gastric mucosa. It is considered that the 3 aforementioned medications are effective in decreasing the overall incidence of UGIB, but it has not been demonstrated that they are efficacious in reducing the incidence of clinically significant UGIB, ie cases that are complicated by anemia, hemorrhagic shock, or death. In addition, the cost and complications resulting from prophylaxis should be taken into consideration, which raises further questions about the systematic use of these agents. This article reviews the current literature on this subject; the authors propose a conservative use of prophylaxis, and that these agents be prescribed in a selective manner to the patients at the greatest risk of developing UGIB.

A protocol for aerosol therapy in acute hospitalized asthmatics.

The most important element in the treatment of acute hospitalized asthmatics is salbutamol administered via wet nebulization prescribed usually on a subjective evaluation of the patient's status. This study outlines a novel protocol that incorporates the FEV1 variable as the major objective parameter in a feedback loop. Data from patients admitted in the year prior to the initiation of the protocol (N = 348) were compared with similar data from patients hospitalized the year following institution of the protocol (N = 238). There were no withdrawals from the protocol due to adverse effects nor were there any deteriorations requiring ICU admission. A significant decrease in the length of hospitalization and the number of salbutamol prescriptions per hospitalization was observed after, relative to before, institution of the protocol (2.2 vs. 2.6 days; 2.3 vs. 3.8; p < .05, respectively). It is concluded that this protocol is safe and efficient, and may also be more efficacious than a nonstandardized approach for treating the hospitalized asthmatic child.

Frequency of upper gastrointestinal bleeding in a pediatric intensive care unit.

OBJECTIVE: To determine the frequency of upper gastrointestinal (GI) bleeding in pediatric ICUs. DESIGN: Prospective, descriptive study. SETTING: Pediatric ICU in a university hospital. PATIENTS: All children admitted to a pediatric ICU over a 55-wk period. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Upper GI bleeding was considered to be present if there was an episode of hematemesis or if any amount of blood was seen in drainage from a nasogastric tube. Sixty-three (6.4%) upper GI bleeds were detected among 984 patients: 5.2% in 698 patients who did not receive upper GI bleeding prophylaxis, and 9.4% in 286 patients who did receive some prophylaxis. Density was defined as the number of events/1000 days.patient. The mean density was 10.8 GI bleeding episodes/1000 days.patient in a pediatric ICU. A multivariate analysis detected four independent risk factors or risk markers for upper GI bleeding: high Pediatric Risk of Mortality score, coagulopathy, pneumonia, and multitrauma. Age, sex, hepatic and respiratory failures were identified as confounding variables. An upper GI bleeding episode was defined as being clinically important if hypotension, death, or transfusion occurred within 24 hrs after the bleeding. There were four clinically important GI bleeding episodes. All were caused, at least in part, by a coagulopathy. The GI bleeding was associated with a need for transfusion in four children, and with hypotension in two. CONCLUSIONS: The frequency of upper GI bleeding is substantial, but the rate of occurrence of clinically important upper GI bleeding is low, even in a pediatric ICU where most patients do not receive any prophylaxis.

[Haemophagocytic sinus histiocytosis or Destombes-Rosai-Dorfman syndrome (author's transl)]. / Histiocytose sinusale hémophagocytaire ou syndrome de Destombes-Rosai-Dorfman.

Haemophagocytic sinus histiocytosis usually presents as cervical lymphadenopathy developing in a context of severe inflammatory reaction. The lymph nodes contain numerous large cytophagic histiocytes capable of absorbing all kinds of blood cells, and diffuse plasmocytic infiltrates. Other organs may be involved, notably the skin and bones, as in the case presented here. The course of the disease if prolonged, irrespective of the treatment administered.

Evaluation of hypertensive therapy in a skilled nursing facility.

Treatment of hypertension in the elderly has recently received increased attention. Both systolic and systolic plus diastolic hypertension are risk factors for cardiovascular and cerebrovascular diseases in patients older than age 65, but the value of antihypertensive therapy in reducing morbidity and mortality has not been adequately studied. The authors evaluated the appropriateness of antihypertensive therapy prescribed for elderly patients in a skilled nursing home and determined the effect reductions in antihypertensive therapy had upon the function and mental status of these patients. Of the 120 patients surveyed, 26.7 percent were found to have a diagnosis of hypertension, and 1/3 of these patients were not receiving any medications at the time of the study. Assessment of the remaining treated patients resulted in a recommendation to alter therapy in 43 percent of the cases. Results from this study suggest that periodic assessment of antihypertensive therapy in long-term care facilities should be considered.

Comparative efficacy of terbutaline sulphate delivered by Turbuhaler dry powder inhaler or pressurised metered dose inhaler with Nebuhaler spacer in children during an acute asthmatic episode.

AIMS: To compare the efficacy of terbutaline sulphate delivered via Turbuhaler with a pressurised metered dose inhaler (pMDI) connected to Nebuhaler spacer in a population of asthmatic children presenting to emergency departments because of an acute episode of asthma. METHODS: Randomised double blind, double dummy, parallel study of acute asthma in the emergency department. A total of 112 children (6-16 years), who had a diagnosis of asthma, a baseline FEV1 of 25-60% of predicted normal value (PNV), and the ability to perform spirometry were studied. Patients received two doses of 0.5 mg/10 kg (maximum 2.0 mg) of terbutaline sulphate at time 0 minutes and time 30 minutes. The two groups were also stratified into subgroups based on FEV1: 25-45% and 45.1-60% PNV. FEV1 before treatment and at two 15-minute intervals after each treatment was the main outcome measure. PIF, PEF, heart rate, SpO2, and tremor were also measured at these times. RESULTS: Both the Turbuhaler and pMDI+Nebuhaler groups showed significant increases from baseline to final value in their FEV1 results, 49% and 50% change from baseline to t = 60 min, respectively (p < 0.001) using last value carried forward. No significant difference was found between the two groups for these results. Subanalysis of the stratified groups revealed similar results. In addition, no significant difference was found in the group and subgroup comparisons for heart rate, SpO2, and tremor. CONCLUSION: Results show that Turbuhaler and pMDI+Nebuhaler are similar in terms of benefit and side effects in the treatment of acute moderate to severe asthma attacks in this study population.

Amino acid sequence of [2Fe-2S] ferredoxin from Clostridium pasteurianum.

The complete amino acid sequence of the [2Fe-2S] ferredoxin from the saccharolytic anaerobe Clostridium pasteurianum has been determined by automated Edman degradation of the whole protein and of peptides obtained by tryptic and by staphylococcal protease digestion. The polypeptide chain consists of 102 amino acids, including 5 cysteine residues in positions 11, 14, 24, 56, and 60. The sequence has been analyzed for hydrophilicity and for secondary structure predictions. In its native state the protein is a dimer, each subunit containing one [2Fe-2S] cluster, and it has a molecular weight of 23,174, including the four iron and inorganic sulfur atoms. The extinction coefficient of the native protein is 19,400 M-1 cm-1 at 463 nm. The positions of the cysteine residues, four of which are most probably the ligands of the [2Fe-2S] cluster, on the polypeptide chain of this protein are very different from those found in other [2Fe-2S] proteins, and in other ferredoxins in general. In addition, whole sequence comparisons of the [2Fe-2S] ferredoxin from C. pasteurianum with a number of other ferredoxins did not reveal any significant homologies. The likely occurrence of several phylogenetically unrelated ferredoxin families is discussed in the light of these observations.

Amino acid sequence of the [4Fe-4S] ferredoxin isolated from Desulfovibrio desulfuricans Norway.

The complete amino acid sequence of the [4Fe-4S] ferredoxin from Desulfovibrio desulfuricans Norway was determined by repetitive Edman degradation of the whole protein and peptides derived from tryptic digestion. The protein has 59 residues. Four of the six cysteine residues are involved in the binding of the [4Fe-4S] cluster in the same arrangement as in clostridial ferredoxins. This sequence is compared to various Desulfovibrio ferredoxin sequences and to the sequence and three-dimensional structure of Peptococcus aerogenes ferredoxin. Evidence of gene duplication is indicated. The requirement of some sequence features in the ferredoxin for an interaction process with its electron transfer partner, cytochrome c3, is postulated in the discussion.