Burnout syndrome among undergraduate nursing students at a public university / Síndrome de Burnout entre estudantes de graduação em enfermagem de uma universidade pública / Síndrome de Burnout entre estudiantes de pregrado en enfermería de una universidad pública

OBJECTIVE: to investigate the burnout syndrome and its relationship with demographic and academic variables among undergraduate nursing students at a public university in Southern Brazil. METHOD: a quantitative study with 168 students, by applying an adaptation of the Maslach Burnout Inventory - Student Survey, validated for this study. We used descriptive and variance analysis of the data analysis. RESULTS: we found that students do not have the burnout syndrome, manifesting high average scores in Emotional Exhaustion, low in Disbelief and high in Professional Effectiveness; that younger students who perform leisure activities have greater Professional Effectiveness, unlike students in early grades with no extracurricular activities; combining work and studies negatively influenced only the Professional Effectiveness factor, while the intention of giving up influenced negatively Disbelief and Professional Effectiveness factors. CONCLUSION: the situations that lead students to Emotional Exhaustion need to be recognized, considering the specificity of their study environments. .

OBJETIVO: investigar a síndrome de Burnout e sua relação com variáveis sociodemográficas e acadêmicas, entre estudantes de graduação em enfermagem de uma universidade pública do Sul do Brasil. MÉTODO: estudo quantitativo, realizado com 168 estudantes, mediante a aplicação de uma adaptação do Maslach Burnout Inventory - Student Survey, validada para este estudo. Utilizou-se a análise descritiva e de variância para análise dos dados. RESULTADOS: constatou-se que os estudantes não apresentam a síndrome de Burnout, manifestando médias altas em exaustão emocional, baixas em descrença e altas em eficácia profissional; que estudantes mais jovens e que realizam atividades de lazer apresentam maior eficácia profissional, diferentemente de estudantes das séries iniciais e que não realizam atividades extracurriculares; conciliar trabalho e estudos influenciou negativamente apenas o fator eficácia profissional, enquanto a intenção de desistir do curso influenciou negativamente os fatores descrença e eficácia profissional. CONCLUSÃO: faz-se necessário o reconhecimento das situações que levam os estudantes à exaustão emocional, considerando a especificidade de seus ambientes de formação. .

OBJETIVO: investigar la síndrome de burnout y su relación con variables sociodemográficas y académicas, entre estudiantes de pregrado en enfermería de una universidad pública del Sur de Brasil. MÉTODO: estudio cuantitativo, desarrollado con 168 estudiantes, mediante la aplicación de una adaptación del Maslach Burnout Inventory - Student Survey, validada para fines de ese estudio. Fueron utilizados los análisis descriptivo y de variancia para analizar los datos. RESULTADOS: se constató que los estudiantes no presentan la síndrome de burnout, manifestando altos promedios en Agotamiento Emocional, bajos en Descreencia y altos en Eficacia Profesional; que estudiantes más jóvenes y que practican actividades de ocio presentan mayor Eficacia Profesional, diferentemente de estudiantes de los años iniciales sin actividades extracurriculares; conciliar trabajo y estudios influyó negativamente apenas el factor Eficacia Profesional, mientras la intención de desistir del curso influyó negativamente los factores Descreencia y Eficacia Profesional. CONCLUSIÓN: es necesario reconocer las situaciones que llevan a los estudiantes al Agotamiento Emocional, considerando la especificidad de sus ambientes de formación. .

Immunodetectable cytochromes P450 I, II, and III in guinea pig adrenal--hormone responsiveness and relationship to capacity for xenobiotic metabolism.

Cytochrome P450s, proteins involved in metabolism of sterols, steroids, and a variety of foreign compounds, have been grouped into families based on amino acid sequence. We have identified a microsomal cytochrome P450 in guinea pig adrenal immunochemically related to P450c,d (P450I), induced in rat liver by methylcholanthrene. The inner zone localization, male predominance, and suppression by ACTH of this protein correspond to the ability of the adrenal microsomes to metabolize ethylmorphine. Its immunoreactivity, localization, and regulation distinguish it from P450(17) alpha (P450XVII) and P450(21) (P450XXI), known microsomal steroid hydroxylases. To examine whether other cytochrome P450s homologous to those in liver might be present in the guinea pig adrenal, microsomes were reacted with antibodies to hepatic P450s from families II and III. Each probe detected proteins in microsomes, but not in mitochondria, which were in the lower mol wt range of cytochrome P450s (47-50K). The immunoreactivity of all was diminished in animals treated with spironolactone, a compound which destroys cytochrome P450s in the adrenal, but not in liver. All were present in both outer and inner zones and in both males and females. None was suppressed by ACTH in the inner zone. Thus, only the previously described 52K protein reactive with anti-P450I corresponds in both distribution and ACTH response to the capacity for xenobiotic metabolism in guinea pig adrenal microsomes. On the other hand, unlike the 52K protein, the newly discovered proteins related to P450s II and III were all suppressed in the outer zone following dexamethasone treatment, suggesting that they might be related to dexamethasone-suppressible functions, such as metabolism of sterols and steroids.

Rapid analysis of non-esterified fatty acids as methyl esters from different biological specimens by gas chromatography after one-step esterification.

A rapid gas chromatographic method for the determination of medium-chain and long-chain free fatty acids (C14:0 to C24:0 fatty acids) from different biological specimens is presented. After a rapid one-step transesterification method in methanol-acetyl chloride (50:1, v/v), fatty acid methyl esters were extracted into n-hexane and analysed on a 15-m Durabond-Wax column within a 12-min chromatographic run. The detection limit is 500 pg per injection.

A time course investigation of vitamin A level and lipid composition of the liver endoplasmic reticulum in rats following treatment with congeneric polychlorobiphenyls.

The drug metabolizing enzyme activities, the vitamin A content and the fatty acid composition in the endoplasmic reticulum membrane were studied in rat liver after a single injection of the polychlorobiphenyls (PCBs) 3,3',4,4'-tetrachlorobiphenyl [(3,4)2Cl] or 2,2',4,4',5,5'-hexachloro-biphenyl [(2,4,5)2Cl], 300 mumol/kg each. The microsomal vitamin A level was markedly lowered 3 days after treatment with (3,4)2Cl, a coplanar type inducer of cytochrome P-450. A marked increase in microsomal AHH and UDPGT activities occurred within 3 days after injection of (3,4)2Cl whereas (2,4,5,)2Cl treatment enhanced APDM activity only. Arachidonic, stearic and linoleic acid microsomal contents were enhanced by the two congeners. (3,4)2Cl caused the proportion of docosahexaenoic acid to decrease. No highly significant correlation was found between the vitamin A content and lipid components in the microsomal membrane. However, the vitamin A level was inversely related to the activities of drug metabolizing enzymes induced by coplanar compounds (cytochrome P-450 towards benzo[a]pyrene and UDP glucuronosyl transferase towards 4-nitrophenol).

Lack of induction of rat liver mixed-function oxidases after chronic administration of high brotizolam doses to rats.

Rats were treated with 10, 200 or 400 mg/kg brotizolam (Lendormin) for 4 weeks, then liver microsomes were prepared and the in vitro transformation of several model substances studied. Furthermore, after similar treatment of rats, the metabolite pattern in the plasma was studied using [14C]brotizolam as a marker. Finally the same investigations were performed after pretreating the rats with the enzyme inducers, phenobarbital or 3-methylchol-anthrene, for 3 days instead of brotizolam. The amount of microsomal protein in the rat liver was increased after all 3 doses of brotizolam, the liver weight after the highest dose only. Activity of the flavoenzyme NADPH cytochrome-c reductase was the only enzyme activity increased after 200 and 400 mg/kg brotizolam, whereas cytochrome P-450 content decreased after 400 mg/kg brotizolam. Activities of the mixed-function oxidases studied were not changed at all. Marked changes after brotizolam administration were seen in the metabolite pattern. The higher doses led to reduced amounts of both of the very polar metabolites. Simultaneously metabolite We 964 (= brotizolam hydroxylated at the methyl group) and the unchanged brotizolam increased several-fold. Treatment of rats with phenobarbital or 3-methylcholanthrene showed the typical but different changes in enzyme activities. The metabolite pattern of brotizolam, however, was not changed. From the results it is concluded that a 4-week treatment of rats with up to 400 mg/kg brotizolam causes no induction of mixed-function oxidases in the liver. The changes of the metabolite pattern described can be discussed as an effect of liver enzyme saturation.

Phenobarbital pretreatment alters the localization of CCl4-induced changes in rat liver microsomal fatty acids.

Phenobarbital treatment induces an isozyme(s) of liver microsomal cytochrome P450 susceptible to CCl4 and enhances the latter's lethality. We have now studied phenobarbital's effect on the specificity of phosphatidyl fatty acid changes in rat liver microsomes. Male Sprague-Dawley rats were pretreated with three daily ip doses of phenobarbital (50 mg/kg) or saline and then orally dosed with CCl4 (2.5 ml/kg). Liver microsomes were prepared 7.5 to 180 min after CCl4 treatment, the lipid fraction was extracted, diene conjugate content was determined, and phospholipids were separated by HPLC for fatty acid content determination. Protein, phospholipid, and phosphatidyl fatty acid residue loss occurred early (7.5 to 30 min) and in some cases later (60 to 180 min) in both pretreated groups, suggesting that two phases of CCl4-mediated injury occurred. Phenobarbital pretreatment accelerated the CCl4-induced formation of diene conjugates in the microsomal lipids. In studies on the separated phospholipids, phenobarbital alone altered microsomal fatty acid content, primarily decreasing arachidonic acid in favor of linoleate, particularly in phosphatidylserine. During the early phase of CCl4 injury, phenobarbital pretreatment shifted the major loss of arachidonic acid from phosphatidylserine to phosphatidylethanolamine. During the later phase, arachidonic acid loss was still prominent, but the most extensive CCl4-induced changes in fatty acids occurred in the neutral lipid fraction, regardless of pretreatment. These changes included loss of neutral lipid linoleic and docosahexanoic acids associated with an increase in palmitic acid. These data demonstrate that phenobarbital pretreatment is associated with a shift in the predominant phospholipid locus from phosphatidylserine to phosphatidylethanolamine for the early CCl4-induced fatty acid changes in rat liver microsomes.

[An immunochemical analysis of the induction of cytochrome P-450 isoforms in the liver of fresh-water fishes by 3-methylcholanthrene, beta-naphthoflavone and aroclor 1254]. / Immunokhimicheskii analiz induktsii izoform tsitokhrom P-450 v pecheni presnovodnykh ryb 3-metilkholantrenom, beta-naftoflavonom i arokhlorom 1254.

The cytochrome P-450 isoforms have been studied in liver microsomes of some fish species from Lake Baikal. Using the inhibitory analysis of microsomal monooxygenase activities carried out by the specific polyclonal antibodies it has been shown that 3-methylcholanthrene, beta-naphthoflavone and arochlor 1254 induce isoforms immunologically related to cytochrome P-488c but not to the rat cytochrome P-450b in fish liver microsomes. The immunologic identity in isoforms of fish and rat cytochromes induced by methylcholanthrene has not been revealed. A possibility to use the method of the inhibitory analysis of fish microsomal activities by specific antibodies to the rat cytochrome P-450 isoforms for biomonitoring and biotesting of polycyclic hydrocarbons and polychlorinated biphenyls in aquatic systems is discussed.

Mass spectroscopy and chromatography of the trichloromethyl radical adduct of phenyl tert-butyl nitrone.

Positive structural identification of the PBN-trichloromethyl spin adduct in vitro was accomplished with the use of high pressure liquid chromatography and/or gas chromatography coupled with mass spectrometry. Both thin layer and liquid chromatography were used to separate a complex mixture of compounds from rat liver extracts treated with CCl4 in vitro and in vivo. Deuterated PBN's (PBN-d9; tert-butyl deuteration, or PBN-d14; both phenyl and tert-butyl deuteration) were also used to aid in the mass spectral analysis of spin adducts from liver extracts of CCl4 exposed rat livers, since the tert-butyl group fragment ion. C4D9+ (m/z = 66) is always present for PBN and PBN spin adducts. In addition, the masses of the ion peaks increase by the amount of deuteration, i.e. an increase of 9 for PBN-d9 or PBN-d14 in comparison to normally synthesized PBN.

Metabolism and brain accumulation of tetrahydroisoquinoline (TIQ) a possible parkinsonism inducing substance, in an animal model of a poor debrisoquine metabolizer.

4-Hydroxytetrahydroisoquinoline (4OH-TIQ) was detected as a metabolite of a possible parkinsonism-inducing substance, tetrahydroisoquinoline (TIQ), in rat liver microsomes and rat urine. Urinary excretion of 4OH-TIQ was significantly reduced in female DA rat, an animal model of a poor debrisoquine metabolizer. The female DA rat also showed significantly higher brain accumulation of TIQ. These results suggest that the metabolic detoxication process is depressed and TIQ accumulation in the brain is enhanced in a poor debrisoquine metabolizer, which may be one possible explanation for poor debrisoquine metabolizers being susceptible to Parkinson's disease.

Spin trapping of free radicals and lipid peroxidation in microsomal preparations from malignant hyperthermia susceptible pigs.

Microsomes were prepared from livers of malignant hyperthermia susceptible (MHS) or resistant (MHR) pigs. On incubation with the spin trap alpha-(4-pyridyl-l-oxide)-N-tert-butylnitrone (4-POBN), the microsomes from MHS pigs produced a characteristic electron spin resonance (ESR) signal at a greater rate than those from MHR pigs. Increased formation in the incubations of thiobarbituric acid reactive substances (TBARS) by the microsomes of the MHS pigs indicated an enhanced susceptibility to free radical-mediated lipid peroxidation. These results provide further evidence that MHS pigs have an antioxidant abnormality which may contribute to the fatal MH response. However the nature of the abnormality is unclear. The enhanced formation of unstable free radicals and indices of lipid peroxidation was not due to decreased vitamin E concentration or glutathione peroxidase activity in the microsomes. Furthermore, fatty acid profiles were similar in microsomes from MHS and MHR pigs indicating similar amounts of potential substrate for TBARS formation.

[Drug interactions of midazolam]. / Les interactions médicamenteuses du midazolam.

Midazolam is a short-acting benzodiazepine with a short half life (1.5-2.5 h) due to intense biotransformation by liver monooxygenases. Anecdotal clinical reports have mentioned a wide interpatient variability in its duration of action. We investigated by in vitro screening factors that could interfere with the rate of midazolam biotransformation (drug-drug interactions). Metabolite production (1'-and 4-OH-midazolam) was monitored in human liver microsomes. Midazolam hydroxylations are inhibited by several drugs (i.e. erythromycin, phenothiazine-type neuroleptics, cyclosporine). The clinical relevance of these drug interactions is illustrated by the example of a patient treated with amiodarone, erythromycin and midazolam during anesthesia. Midazolam-induced sleep lasted about 6 days due to inhibition of its biotransformation by concomitant drug treatment.

Desorption of ions from rat membranes: selectivity of different ionization techniques.

Complex lipid biomarkers, including phosphatidylcholines, cerebrosides and sulfatides, are shown to be desorbed intact from rat brain myelin and rat liver microsomes by liquid secondary ion mass spectrometry, by plasma desorption and by laser desorption. Different polar lipids are favored by the different desorption techniques and as negative or positive ions. These selectivities support current theories about ionization for the different techniques.

Selenium-containing proteins of rat kidney and liver microsomes.

Selenium (Se)-containing proteins in microsomal fractions of rat kidney and liver were investigated after isotopic labeling of rats with [75Se]selenite. More than 85% of the 75Se in the solubilized microsomal extracts precipitated with protein after trichloroacetic acid treatment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), used to separate the labeled protein subunits in the solubilized microsomal extracts, revealed several 75Se-containing proteins in addition to glutathione peroxidase. 75Se-labeled subunits with molecular weights of 55, 30, 26, 22, 19, and 17 kDa were present in microsomal fractions of kidney and liver. The 75Se-labeled tryptic peptide of the 55 kDa subunit had the same Rf value on a 17% SDS-PAGE gel as the peptide from plasma selenoprotein P. A time-course study of the labeling of individual protein subunits in kidney and liver microsomes from Se-supplemented and Se-deficient rats showed that most of the 75Se was associated with the 55 kDa subunit 3 hr after injection. The amount of 75Se associated with this protein subunit decreased by 12 hr, with a concurrent increase in the labeling of lower molecular-weight subunits. The results support the hypothesis that there is a mechanism for transfer of Se from the 55 kDa subunit to other Se-containing proteins.

[The microsomal oxidation system of the liver in the aging of animals with various specific lifespans]. / Sistema mikrosomal'nogo okisleniia pecheni pri starenii zhivotnykh s razlichnoi vidovoi prodolzhitel'nost'iu zhizni.

Experiments, carried out on adult and old animals with different specific lifespan (rat, guinea pig, rabbit, and dog), revealed age-related changes in content and activity of liver microsomal oxidation enzymes (cytochrome P-450, b5, aminopyrine demethylase, aniline hydroxylase). The changes become more pronounced with age. This allows to classify these species as chronobiological ones. A negative correlation between the specific lifespan and the level of decrease in activity of aminopyridine demethylase, an integral index of electron transport rate in microsomal chain, in aged animals was established.

Proteins associated with somatogenic and lactogenic receptors in microsomal membranes and intact rat hepatocytes.

Lactogenic and somatogenic receptors present in rat liver have been examined by cross-linking with a derivative of human somatotropin (AP-hGH1) followed by SDS-polyacrylamide gel electrophoresis. AP-hGH1, which has a content of 2.2 azidophenacyl groups per molecule, mainly linked to half Cys-182 and half Cys-189, exerted a specificity similar to that of the native hormone (hGH), with an ability of 46% with respect to hGH to compete with the radiolabelled hormone for the binding sites of microsomal preparations. Photolysis of the 125I-labelled derivative bound to the lactogenic receptors present in either microsomal membranes or Triton X-100 solubilized preparations gave rise to a 63 kDa species. In addition, 30% of the covalent complexes formed in microsomal membranes belonged to a species with a molecular mass of 70 kDa. Incubation of viable rat hepatocytes with the radiolabelled derivative at either 0 degrees C for 3 h or 15 degrees C for 1.5 h and subjection to irradiation, yielded covalent complexes of molecular masses estimated at 130, 73, 63, 45 and 35 kDa. Experiments performed in the presence of 1 mM NaCN, gave rise to the previous species in a similar yield as that obtained in the absence of cyanide. The 130 kDa complex is related to the somatogenic binding sites, since it was not visualized in the presence of unlabelled bovine somatotropin, while the 70-73, 63, 45 and 35 kDa bands disappeared when the incubations were performed in the presence of unlabelled ovine prolactin.

Determination of thiobarbituric acid-reactive substances in oxidized lipids by high-performance liquid chromatography with a postcolumn reaction system.

A new high-performance liquid chromatography procedure with a postcolumn reaction system for determination of free malondialdehyde (MDA) and other thiobarbituric acid-reactive substances (TBA-RS) in oxidized lipids in vitro has been developed. Using this procedure, both thermally oxidized methyl linoleate and the degradation products of methyl linoleate hydroperoxides revealed many kinds of lipophilic TBA-RS, but no free MDA was detected on the high-performance liquid chromatography. Similarly, oxidized methyl arachidonate also produced certain kinds of TBA-RS in the lipophilic phase and a small amount of free MDA in the hydrophilic phase. These results indicate that lipophilic TBA-RS produced in oxidized lipids in vitro are major TBA-RS and that the production of free MDA is small, even though the degree of lipid oxidation has previously been estimated as an MDA equivalent measured by the TBA colorimetric test.

Heterogeneity of native rat liver elongation factor 2.

The high heterogeneity of native rat liver EF-2 prepared from either 105000 x g supernatant or microsome high-salt extract was detected by two-dimensional equilibrium isoelectric focusing-SDS-polyacrylamide gel electrophoresis in the presence of 9.5 M urea. Five spots were always detected, all of Mr 95,000, which were not artefactual for their amount varied when EF-2 was specifically ADP-ribosylated by diphtheria toxin in the presence of NAD+, and/or phosphorylated on a threonine residue by a Ca2+/calmodulin-dependent protein kinase (most likely Ca2+/calmodulin-dependent protein kinase III described by others [(1987) J. Biol. Chem. 262, 17299-17303; (1988) Nature 334, 170-173]). Results of ADP-ribosylation and/or phosphorylation experiments with either unlabeled or labeled reagents ([14C]NAD and [32P]ATP) strongly suggest that our preparation contained native ADP-ribosylated and native phosphorylated forms which could be estimated at about 20% and 40% of the whole EF-2. Phosphorylated and ADP-ribosylated forms of EF-2 could be ADP-ribosylated and phosphorylated, respectively, but a native form both ADP-ribosylated and phosphorylated was not detected. Our results also suggest the existence of a minor native form of EF-2 and of its phosphorylated and ADP-ribosylated derivatives.

Purification and characterization of hepatic microsomal prostaglandin omega-hydroxylase cytochrome P-450 from pregnant rabbits.

Prostaglandin omega-hydroxylase, designated as cytochrome P-450 LPG omega (P-450 LPG omega), has been purified, to a specific content of 15 nmol of cytochrome P-450/mg of protein, from liver microsomes of pregnant rabbits. The purified P-450 LPG omega was found to be homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and to have an apparent molecular weight of 52,000. The enzyme showed a maximum at 450 nm in the carbon monoxide (CO)-difference spectrum for its reduced form. This cytochrome P-450 efficiently catalyzed the omega-hydroxylation of prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), prostaglandin F2 alpha (PGF 2 alpha), prostaglandin A1 (PGA1), and prostaglandin A2 (PGA2), as well as the omega- and (omega-1)-hydroxylation of myristate and palmitate, in a reconstituted system containing cytochrome P-450, NADPH-cytochrome P-450 reductase, phospholipid, and cytochrome b5. Various monovalent and divalent cations further stimulated these reactions in the presence of cytochrome b5. In addition, the reactions were also markedly enhanced by various organic solvents, such as ethanol and acetone. This cytochrome P-450 showed no detectable activity toward several xenobiotics tested. P-450 LPG omega was very similar or identical to the pulmonary prostaglandin omega-hydroxylase (P-450p-2) (Yamamoto, S., Kusunose, E., Ogita, K., Kaku, M., Ichihara, K., & Kusunose, M. (1984) J. Biochem. 96, 593-603) in its molecular weight, absorption spectra, catalytic activity, peptide mapping pattern, and N-terminal amino acid sequence. However, P-450 LPG omega was more unstable than P-450p-2 on storage. In sharp contrast to P-450p-2, P-450 LPG omega was not induced by progesterone.

Detection of GTP-binding proteins in purified derivatives of rough endoplasmic reticulum.

As a first step in determining the molecular mechanism of membrane fusion stimulated by GTP in rough endoplasmic reticulum (RER), we have looked for GTP-binding proteins. Rough microsomes from rat liver were treated for the release of ribosomes, and the membrane proteins were separated by SDS/polyacrylamide-gel electrophoresis. The polypeptides were then blotted on to nitrocellulose sheets and incubated with [alpha-32P]GTP [Bhullar & Haslam (1987) Biochem. J. 245, 617-620]. A doublet of polypeptides (23 and 24 kDa) was detected in the presence of 2 microM-MgCl2. Binding of [alpha-32P]GTP was blocked by 1-5 mM-EDTA, 10-10,000 nM-GTP or 10 microM-GDP. Either guanosine 5'-[gamma-thio]triphosphate or guanosine 5'-[beta gamma-imido]triphosphate at 100 nM completely inhibited binding, but ATP, CTP or UTP at 10 mciroM did not. Pretreatment of microsomes by mild trypsin treatment (0.5-10 micrograms of trypsin/ml, concentrations known not to affect microsomal permeability) led to inhibition of [alpha-32P]GTP binding, suggesting a cytosolic membrane orientation for the GTP-binding proteins. Two-dimensional gel-electrophoretic analysis revealed the 23 and 24 kDa [alpha-32P]GTP-binding proteins to have similar acid isoelectric points. [alpha-32P]GTP binding occurred to similar proteins of rough microsomes from rat liver, rat prostate and dog pancreas, as well as to a 23 kDa protein of rough microsomes from frog liver, but occurred to distinctly different proteins in a rat liver plasma-membrane-enriched fraction. Thus [alpha-32P]GTP binding has been demonstrated to two low-molecular-mass (approx. 21 kDa) proteins in the rough endoplasmic reticulum of several varied cell types.