A prospective study on self-assessed mental well-being and work capacity as determinants of all-cause sickness absence.

PURPOSE: The aim of the present study was to estimate whether self-assessed mental well-being and work capacity determines future sickness absence (SA). METHODS: A questionnaire was sent to employed individuals (n = 6,140), aged 19-64 years, who were registered as sick-listed with a new sick-leave spell in 2008. The response rate was 54 %. In this study we included individuals with a single sick-leave spell in 2008 (n = 2,502). The WHO (Ten) Well-Being Index and four dimensions of self-assessed work capacity (knowledge, mental, collaborative, physical) were used as determinants. Future sickness absence was identified through national register in 2009. Outcome was defined as no sickness benefit compensated days (no SBCD) and at least one sickness benefit compensated day (SBCD). Logistic regression analyses were used to estimate odds ratios (OR) with 95 % confidence intervals (CI) for the likelihood of SBCD. RESULTS: In 2009, 28 % of the women and 22 % of the men had SBCD; the median was 59 and 66 benefit days, respectively. Individuals with low mental well-being had higher odds for SBCD with OR 1.29 (95 % CI 1.01-1.65) in the fully adjusted model. Participants reporting low work capacity in relation to knowledge (OR 1.55, 95 % CI 1.13-2.13), collaborative (OR 1.36, 95 % CI 1.03-1.79) and physical (OR 1.50, 95 % CI 1.22-1.86) demands at work had higher odds for SBCD after adjustments for all covariates; no relation was demonstrated with mental work capacity (OR 0.99, 95 % CI 0.76-1.27). CONCLUSION: Mental well-being and work capacity emerged as determinants of future SA. Screening in health care could facilitate early identification of persons in need of interventions to prevent future SA.

Recognition of bladder instability on voiding cystourethrography in infants with urinary tract infection.

PURPOSE: We evaluate voiding cystourethrography as a method for identifying bladder instability in infants. MATERIALS AND METHODS: Cystometry was combined with voiding cystourethrography in 79 male and 64 female infants with first time urinary tract infection. Bladder wall irregularity, elongation of bladder shape, and filling of the posterior urethra were transient radiological signs occurring during bladder filling and were considered to reflect bladder instability. A pediatric radiologist looked for these signs on all 480 films exposed during bladder filling. The results were correlated to simultaneous detrusor pressure recordings. The analysis was repeated independently by a urologist to evaluate the reliability of the radiological signs used. RESULTS: The sensitivity and specificity were both 90% in the evaluation of radiological signs of bladder instability. Filling of the posterior urethra was the least frequently reported radiological sign, which was seen at 53% of unstable contractions. However, when this sign was reported, instability was usually correctly detected (85%). Evaluation accuracy had improved with increasing numbers of noted signs per film. This accuracy had included 29%, 67% and 91% of unstable contractions that were correctly diagnosed when 1, 2 or 3 signs were noted, respectively. The number of noted signs was positively related to the strength of the unstable detrusor contraction. Urologist evaluations had similar results to the radiologist, although the sensitivity was somewhat lower (79% and 90%, respectively). CONCLUSIONS: Unstable detrusor contractions could be identified in infants by evaluation of radiological signs on voiding cystourethrography. Findings of bladder wall irregularity, elongation of bladder shape and filling of the posterior urethra indicated unstable detrusor contraction. The more such findings are observed, the stronger the indication.

Natural filling cystometry in small boys with posterior urethral valves: unstable valve bladders become stable during sleep.

PURPOSE: Our aim was to demonstrate the voiding pattern in small boys with posterior urethral valves during the day and night. MATERIALS AND METHODS: Long-term natural filling and standard cystometry was performed in 16 boys 1.4 to 6 years old (mean age 3.4) in whom posterior urethral valves were diagnosed in infancy. The boys were divided into 2 groups according to whether they had day incontinence. RESULTS: All boys had instability in the daytime but at night bladders were mainly stable. Voiding frequency during the day was high at a mean of 1.7 and 0.5 voidings per hour in the day incontinent and day continent groups, respectively, compared to 0.1 voiding per hour at night in both groups. Voiding detrusor pressure was higher and functional bladder capacity was lower during the day than at night in both groups. CONCLUSIONS: Natural filling cystometry revealed pronounced instability during the day and stable bladders at night. This difference between day and night is an important factor contributing to frequent small voidings during the day, dry nights and high bladder volume in the morning.

Submicellar complexes may initiate the fungicidal effects of cationic amphiphilic compounds on Candida albicans.

The killing of Candida albicans by a series of amphiphilic quaternary ammonium compounds (QACs) with different hydrocarbon chain lengths was closely related to the binding of the compounds to the cells and damage of the cell membranes. The membrane damage was measured as the level of release of the UV-absorbing material into the medium in which the cells were suspended and as the level of uptake of propidium iodide in individual cells by flow cytometry. It was shown that of the compounds tested, hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide [CTAB]) bound most efficiently. Tetradecyl betainate chloride (B14), tetradecanoylcholine bromide (C14), tetradecyltrimethylammonium bromide (TTAB), and dodecyltrimethylammonium bromide (DTAB) followed and had declining degrees of binding efficiency. The proportion of CTAB bound was almost total at concentrations up to the critical micelle concentration (CMC) of the compound, whereas that of B14 was somewhat smaller. For the two remaining tetradecyl compounds (C14 and TTAB), still smaller proportions were bound at low concentrations, but the proportions rose disproportionally at increasing concentrations to a distinct maximum at concentrations of 0.2 to 0.5 times the CMC. We propose that interfacial micelle-like aggregates are formed at the cell surface as a step in the binding process. An analogous, but less conspicuous, maximum was seen for DTAB. Thus, great differences in the binding affinity of QACs with different hydrocarbon chains at different concentrations to C. albicans were observed. These differences were related to the CMC of the compound. In contrast, the binding of TTAB to Salmonella typhimurium 395 MS was almost total at low as well as high concentrations until saturation was attained, indicating fundamental differences between binding to the yeast and binding to gram-negative bacteria. The importance of lipid-type complexes or aggregates to the antifungal effect of membrane-active substances are discussed.

Enzymatic hydrolysis of long-chain alkanoylcholines in rat intestinal loops.

BACKGROUND: The hydrolysis of long-chain alkanoylcholines, presumably catalyzed by butyryl-cholinesterase (EC 3.1.1.8), in rat intestinal loops was studied. The substances have earlier been found to be rapidly degraded in vitro. METHODS: Radiolabeled substrates were used, and a radiochromatographic detection method was applied. RESULTS AND CONCLUSION: The long-chain alkanoylcholines were rapidly hydrolyzed. The rates of the reaction and the chain-length dependence were similar to those reported earlier in vitro. At high substrate concentrations the hydrolysis reaction was inhibited. This could be due to conformational changes of the enzyme, caused by the adsorption of the cationic amphiphile, or to a decrease in the free substrate concentration after incorporation of the amphiphilic ester into the lipid layer of the cell membranes. The enzymatic activity towards the substrates in different parts of the rat intestinal tract was also studied and found to be highest in the duodenum.

Long-chain alkanoylcholines, a new category of soft antimicrobial agents that are enzymatically degradable.

A new category of amphiphilic hydrolyzable quaternary ammonium compounds with rapid and high levels of antimicrobial activity was studied. The compounds, alkanoylcholines with hydrocarbon chains of 10 to 14 carbon atoms, are hydrolyzed by butyrylcholine esterase, which is present in human serum and mucosal membranes. The hydrolysis products are common components of human metabolism. Alkanoylcholines were tested and found to be active against gram-negative and gram-positive bacteria as well as yeasts. The microbicidal activities of the alkanoylcholines were comparable to the activities of the stable quaternary ammonium compounds of corresponding chain length and increased with an increasing number of carbon atoms. The compounds were also found to be hydrolyzed by enzymes present in certain microorganisms. The degradation was achieved after reaching the microbicidal effect.

Butyrylcholinesterase activity towards long-chain alkanoylcholines: kinetics and mechanism.

The hydrolysis of long-chain alkanoylcholines catalyzed by butyrylcholinesterase (EC 3.1.1.8) has been studied. Radiolabelled substrates have been used and a radiochromatographic detection method developed earlier has been applied. The long-chain choline esters were found to be excellent substrates for butyrylcholinesterase at low concentrations, with Km values lower than those of short-chain analogues. At higher substrate concentrations, however, the hydrolysis reaction is inhibited, due to the formation of mixed micelles between the amphiphilic substrate and the corresponding alkanoic acid formed in the hydrolysis reaction. The inhibition may also partially be the result of conformational changes of the protein following adsorption of the cationic amphiphile. Critical micelle concentrations (CMC) for the long-chain substrates, as well as for mixed micelles, have been determined.

Liquid chromatographic monitoring of pseudocholinesterase activity: comparison of methods.

In order to study the activity of pseudocholinesterase in vitro, two liquid chromatographic techniques have been developed. One is based on phase transfer-catalyzed (PTC) esterification of the carboxylic acid formed during hydrolysis of the substrate, and the other on the use of a radioisotopically labeled substrate. In both cases, the substrate used was a long-chain choline ester. The PTC method, utilizing (N-9-acridinyl)bromoacetamide as a fluorogenic labeling reagent in an aqueous-organic two-phase system, gives esters with very high fluorescence intensity. The radiochromatographic method makes use of on-line radioactivity monitoring of the substrate and product in order to follow the hydrolysis reaction. In both methods reversed-phase liquid chromatography is used. A method for the synthesis of 3H-labeled choline esters is also described. Both techniques are compared with regard to sensitivity, reproducibility and practical considerations.

N-(9-acridinyl)-bromoacetamide--a powerful reagent for phase-transfer-catalyzed fluorescence labeling of carboxylic acids for liquid chromatography.

Phase-transfer-catalyzed esterification of various carboxylic acids has been carried out on a microanalytical scale with a new reagent, N-(9-acridinyl)-bromoacetamide, in aqueous/organic two-phase systems. The procedure gives esters showing very high fluorescence intensity in acid solution. The large Stokes' shift (greater than 120 nm) means that a low background can be achieved even when using a large emission bandwidth. These derivatives show very good chromatographic behavior on reversed-phase liquid chromatographic columns with the use of aqueous acetonitrile, containing 0.2% of phosphoric acid, as the mobile phase. Detection limits (S/N = 2) as low as 10 fmol can be obtained under optimal conditions.