Family cohesion and family size moderating burnout and recovery connection.

BACKGROUND: It has been argued that family issues in individual cultures do not correlate with fulfilment. However, the universality of these findings is unknown as they are based on data from the Western world. AIMS: To examine the connection between job burnout and recovery and the moderating effects of perceived family cohesion and family size in this relationship. METHODS: Moderated hierarchical regression analyses were carried out on a sample of medical practitioners working in intensive care units from federal and state-owned hospitals in Southeastern Nigeria. RESULTS: There were 183 participants. Job burnout was negatively related to recovery and perceived family cohesion was positively related to recovery. However, contrary to our assumption, family size was positively related to recovery. Perceived family cohesion was vital in recovery regardless of the doctors' experience of high levels of burnout. In contrast to most previous findings, family size was found to have a moderating effect in the burnout-recovery connection. CONCLUSIONS: The findings of this study suggested that family bond is important in collectivistic cultures. This was underscored by the moderating effects family issues had on the relation between burnout and recovery. These findings are different from those in Western societies in which previous studies have been conducted.

Novel malaria control by strategic net-hoisting with S/O channel/grip devices.

Background: Hoisting of netting screens with battens on windows/vents suffers from unsightly gathering of dust and allergens, which may provoke respiratory diseases and therefore lack popularity as a mosquito/malaria control tool. Furthermore, installing them in high-rise buildings can be cumbersome and risky. An S/O channel/grip device was, therefore, conceived to eliminate impediments to screening windows/openings in houses. Methods: Thin sheet metal strips were transformed into s-shaped channels. The lower ends provided for attachment to buildings while the upper ends allowed net attachments with O-rubber pipes. Effectiveness was ascertained by applying these to screen a room against adult Anopheles and Aedes mosquitoes. Net hoisting/de-hoisting periods were measured for windows at various locations, and opinions of bystanders were obtained. Results: The device maintained a firmgrip of metal, fabric or natural nets placed on them. Over a 7-day period, 1036 mosquitoes could not enter rooms protected by either the novel or the traditional methods. Placement/removal of nets with the new device on experimental windows had a mean of 4.5/1 min, respectively, with all the nets intact, hence being reusable; whereas the traditional method had a mean of 4.25/8.75 min with all the nets torn/not-reusable. In high-rise buildings, employing ladders/scaffolds to mount nets were unnecessary: period of hoisting/removal on windows was 11/2 min irrespective of the location of windows whereas the traditional method hoisting period increased substantially as the height of the window increased. Conclusion: S/O channel/grip devices can improve mosquito control through screening because it engenders net hoisting on windows that is simple, effective, affordable, accessible and convenient, especially on high-rise buildings. The intact removal and recovery of used nets creates opportunities for cleaning them, retreatment with insecticide, regular maintenance, etc. which underline its potential roles in control of asthma and insect-borne diseases.

Matrix metalloproteinase deficiencies do not impair cell-associated fibrinolytic activity.

The matrix metalloproteinase (MMP) and fibrinolytic (plasminogen/plasmin) systems cooperate in many (patho)physiological processes requiring extracellular proteolysis. The effect of MMP-3 (stromelysin-1), MMP-7 (matrilysin), MMP-9 (gelatinase B) or MMP-12 (metalloelastase) on cellular fibrinolytic activity was studied with the use of smooth muscle cells (SMC) and fibroblasts derived from mice with specific inactivation of these genes. Activation of cell-bound plasminogen by two-chain urokinase-type plasminogen activator (tcu-PA) was not significantly different with SMC or fibroblasts from the gene-deficient mice (78% to 140% of wild-type). For all cell types, very limited conversion of plasminogen to angiostatin-like kringle-containing fragments was observed (< 3% of the total cell-bound plasminogen). Activation of plasminogen in solution by cell-associated tcu-PA was also comparable for SMC or fibroblasts of the different genotypes (54% to 160% of wild-type). In vitro SMC migration on scrape wounded collagen-coated surfaces was comparable for wild-type, MMP-7(-/-), MMP-9(-/-) and MMP-12(-/-) SMC, but was significantly reduced for MMP-3(-/-) SMC (P < .005 vs. wild-type). Serum-free conditioned medium of MMP-3(-/-) and MMP-7(-/-) SMC or fibroblasts induced similar lysis of fibrin films as wild-type cells. These findings indicate that several interactions that have been described between these MMPs and the plasminogen/plasmin system in a purified system do not significantly affect plasmin-mediated cellular fibrinolytic activity under cell culture conditions.

Specific proteolysis of human plasminogen by a 24 kDa endopeptidase from a novel Chryseobacterium Sp.

A novel single polypeptide endopeptidase of 24 kDa (24k-endopeptidase) was purified with a yield of 300-400 microg/L from conditioned medium of a bacterial strain which was identified as a new species in the genus Chryseobacterium Sp. on the basis of its 16S rDNA sequence and DNA:DNA hybridizations. The NH(2)-terminal amino acid sequence (Val-Ala-Thr-Pro-Asn-Leu-Glu-.) was not found in the availabe databases. The 24k-endopeptidase specifically hydrolyzed the Ser(441)-Val(442) peptide bond in human plasmin(ogen), with additional cleavage of the Lys(78)-Val(79) and Pro(447)-Val(448) peptide bonds, and a secondary cleavage at Lys(615)-Val(616). Thereby, plasminogen is converted into an angiostatin-like fragment containing kringles 1-4 (K1-4) and miniplasminogen (kringle 5 and the serine proteinase domain). The purified K1-4 fragment showed a comparable cytotoxicity toward endothelial cells as the elastase-derived K1-3 fragment (12.7% versus 10.6% at a concentration of 10 microg/mL). Plasminogen, bound to monocytoid THP-1 cells, was also cleaved by the 24k-endopeptidase, resulting in generation of an angiostatin-like fragment and in a decreased capacity to generate cell-associated plasmin following activation by urokinase. The 24k-endopeptidase was not efficiently neutralized by specific inhibitors against the serine, cysteine, aspartic, or matrix metalloproteinase classes of enzymes. In human plasma or serum, however, it induced only very limited plasminogen degradation, apparently due to neutralization of its activity by alpha(2)-macroglobulin. Interaction of this novel 24k-endopeptidase with plasminogen thus yields an angiostatin-like fragment and affects plasmin-mediated cellular proteolytic activity.

Modulation of cell-associated plasminogen activation by stromelysin-1 (MMP-3).

Stromelysin-1 (MMP-3) cleaves a 55 kDa kringle 1-4 fragment, containing the lysine-binding site(s) involved in cellular binding, from 92 kDa plasminogen and removes a 17 kDa NH2-terminal fragment, containing the cellular receptor-binding site, from 45 kDa urokinase (u-PA), but a potential role of MMP-3 in the regulation of cellular fibrinolytic activity by affecting binding and/or activation of plasminogen and/or single-chain u-PA has not been established. Human plasminogen (input concentration 100 nM for 4x10(6) cells per ml) was shown to bind specifically to human monocytoid THP-1 cells, to murine MMP-3 deficient smooth muscle cells (SMC) and fibroblasts (1.9, 0.92 and 1.0x10(6) molecules per cell, respectively). Treatment with MMP-3 (final concentration 0-50 nM) of cells saturated with bound plasminogen (about 25 nM), overnight at 37 degrees C, resulted in a dose-dependent reduction of the amount of u-PA activatable plasminogen (reduction to 25-40% of the value in the absence of MMP-3). Immunoblotting with specific monoclonal antibodies and autoradiography of eluates of the cells treated with MMP-3 revealed cleavage of plasminogen into the 55 kDa fragment and miniplasminogen (kringle 5 plus the proteinase domain). Binding of human single chain u-PA (scu-PA) to human THP-1 and HT 1080 cells amounted to 2.5x10(6) and 7.1x10(6) molecules per cell, respectively. Treatment with MMP-3 (final concentration 0-25 nM) of cell-bound u-PA (about 17 nM for THP-1 and 47 nM for HT1080 cells), overnight at 37 degrees C, did not alter cell-associated u-PA activity, measured in a direct chromogenic substrate assay or in a plasminogen-coupled chromogenic substrate assay (residual u-PA activity always > or =85% of that without MMP-3 treatment). Autoradiography of 125I-labeled u-PA moieties, removed from the cells by treatment with acid or with phosphatidylinositol phospholipase C, confirmed that u-PA remained essentially intact after MMP-3 treatment. These data indicate that MMP-3 may downregulate cell-associated plasmin activity by decreasing the amount of activatible plasminogen, without affecting cell-bound u-PA activity.

The effects of sun-drying surfaces and packaging materials on the storability of cowpea (Vigna unguiculata) seed.

The effects of sun-drying cowpea seeds for three hours on cement (CS), wood (WS), and corrugated iron sheet (CIS) surfaces and packaging separately in polyethene and jute bags were studied. Moisture-gain, and resistance to insect and mold damage were monitored monthly for six months, while proximate analyses on day zero and at the 6th month were conducted. Results showed that the three-hour sun-drying of cowpea seeds on reflective surfaces (CIS and CS) enhanced the rate of moisture-reabsorption during storage and consequently, the degree of mold and insect damage irrespective of the packaging material employed. Crude fat, fiber and ash contents, unlike protein and moisture contents, remained virtually constant (p < or = 0.05). In this study, the wood surface and polyethene bag were the most preferred treatments to store sun-dried cowpea seeds for about 5.7 months.

A comparative study on the photocytotoxicity of hypericin on A431 cells using three different assays.

BACKGROUND: Three assay models were adopted for assessing the photocytotoxicity of hypericin on A431 cells. The cells were incubated for 1 hour or 24 hours with hypericin to evaluate the importance of the incubation period on the exerted photocytotoxicity. MATERIALS AND METHODS: A neutral red, an antiproliferative and a tetrazolium-reduction (MTT) assay were used for the estimation of cytotoxicity. RESULTS: IC50 values were 296, 321 and > 500 nM after 1 hour, and to 70, 54 and 277 nM after 24 hours, for the neutral red, antiproliferative and MTT assays, respectively. CONCLUSIONS: Our results clearly show that it is imperative to incubate cells for long periods to fully assess the hypericin photocytotoxicity, and that the neutral red assay is as sensitive as the antiproliferative assay but superior to the MTT assay at detecting hypericin cell damage.

Proteolytic cleavage of urokinase-type plasminogen activator by stromelysin-1 (MMP-3).

Matrix metalloproteinase-3 (MMP-3, or stromelysin-1) specifically hydrolyzes the Glu143-Leu144 peptide bond in 45-kDa single-chain urokinase-type plasminogen activator (scu-PA) and in its two-chain (tcu-PA) derivative, yielding a 17-kDa NH2-terminal domain comprising the u-PA receptor (u-PAR) binding site and a 32-kDa COOH-terminal moiety containing the serine proteinase domain of u-PA. The conversion is completely abolished in the presence of the MMP inhibitors EDTA or 1,10-phenanthroline. Biospecific interaction analysis indicates that binding of MMP-3 occurs through the 32-kDa fragment. The 32-kDa fragment derived from scu-PA (scu-PA-32k) has a specific activity of

Generation of an angiostatin-like fragment from plasminogen by stromelysin-1 (MMP-3).

Matrix metalloproteinase-3 (MP-3 or stromelysin-1) specifically hydrolyzes the Glu59-Asn60, Pro447-Val448, and Pro544-Ser545 peptide bonds in plasminogen, yielding a 55 kDa NH2-terminal angiostatin-like domain (comprising kringles 1-4), a 14 kDa domain comprising kringle 5, and a 30 kDa domain comprising the serine proteinases domain. The conversion is completely abolished in the presence of the MMP inhibitors EDTA or 1,10-phenanthroline. Biospecific interactions analysis indicates that binding of proMMP-3 and MMP-3 to plasminogen occurs with comparable affinity (KA of 4.7 x 10(6) and 4.1 x 10(6) M-1, respectively) and is mediated via the miniplasminogen moiety (kringle 5 plus the proteinase domain) and via the catalytic domain of MMP-3. Thus, proteolytic cleavage of plasminogen by MMP-3 generates angiostatin-like fragments.