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Biomedical subjects

M C Henderson

Publications and source records attributed to M C Henderson.

At least 37 records · Page 2Linked to original sources

Occupational stress and organizational commitment in nurse administrators.

OBJECTIVE: The authors explore levels of occupational stress (burnout) and organizational commitment (intent to stay), their inter-relationships, and their relationships to personal and organizational factors in nurse administrators. BACKGROUND: Although the concepts of burnout and turnover have been studied and reported for staff nurses, relatively few such studies exist in relation to nurse administrators. METHODS: Consequently, the Maslach Burnout Inventory, the Organizational Commitment Questionnaire, and a personal data sheet were completed by respondents to a mailed survey representing 65.6% of the membership of the state's nurse executive organization and 58.2% of the state's hospitals (N = 78). RESULTS: Scores indicate that half the respondents experience low levels of burnout whereas a third have high levels of burnout. Commitment scores were high for most nurse executives and were correlated inversely with burnout scale scores (depersonalization, personal accomplishment, emotional exhaustion), with the amount or phase of burnout, and with non-nursing management experience. Those with few opportunities to meet with colleagues scored higher on emotional exhaustion and lower on personal accomplishment scales. Intent to stay (high commitment scores) was related positively to perceived organizational support and to religiosity. CONCLUSIONS: Findings are consistent with those reported in other studies; however, the administrative role may require unique approaches to avoid or correct organizational stress. The role of social support, the determination of organizational/individual fit, and the adaptation of traditional organizational development techniques to the administrative role are discussed and proposed as areas for further study.

Adult↗

Inhibition of in vitro aflatoxin B1-DNA binding in rainbow trout by CYP1A inhibitors: alpha-naphthoflavone, beta-naphthoflavone and trout CYP1A1 peptide antibody.

Rainbow trout cytochrome P450 (CYP)1A detoxifies aflatoxin B1 (AFB1) to aflatoxin M1 (AFM1), whereas CYP2K1 activates AFB1 to AFB1-8,9-epoxide. We report that alpha-naphthoflavone (ANF) and beta-naphthoflavone (BNF) both strongly inhibit CYP1A-mediated ethoxyresorufin O-deethylase (EROD) activity (Ki = 9.1 +/- 0.8 and 7.6 +/- 1.1 nM, respectively). These inhibitors (selective for mammalian CYP1A at low concentrations), as well as rabbit polyclonal antibody to a trout CYP1A1 peptide (residues 277-294), also strongly inhibited trout microsome-catalyzed AFB1-DNA binding and lauric acid (omega-1) hydroxylation in vitro, reactions previously established to be CYP2K1-dependent. ANF at 0.5, 5, 50 and 500 microM inhibited liver microsome-catalyzed AFB1-DNA binding by 22, 58, 84 and 91%, respectively, whereas BNF at the same concentrations inhibited 22, 74, 78 and 81%, respectively. The CYP1A1 peptide and CYP2K1 polyclonal antibodies (10 mg IgG/mg microsomal protein) inhibited AFB1-DNA binding by 84 and 66%, respectively, compared with pre-immune IgG. Lauric acid (omega-1) hydroxylation was inhibited 61% by 5 microM ANF, 69% by 5 microM BNF and 100% by either antibody at 12 mg IgG/mg microsomal protein. These results demonstrate that mammalian CYP1A inhibitors also inhibit trout microsomal AFB1-DNA binding and lauric acid (omega-1) hydroxylation, catalyzed primarily by CYP2K1. In the absence of evidence that trout CYP1A can catalyze AFB1-DNA binding, the results suggest configuration similarities at, or near, the active sites for these two fish enzymes that result in antibody crossreaction and loss of the inhibitor specificity observed with mammalian CYP1A.

Aflatoxin B1↗

Abnormal uterine bleeding.

Concerns about abnormal menstrual bleeding are a common reason for women to consult a primary care physician. The first step in the evaluation is to determine the patient's ovulatory status. Women with heavy bleeding but normal ovulatory cycles should be evaluated for coagulopathies, structural lesions, and hypothyroidism. In the absence of a systemic or structural cause, menorrhagia can be treated with OCPs or NSAIDs. Intermenstrual bleeding in OCP users may be due to noncompliance or the use of low-dose pills. Encouraging patient compliance and adjustment of the estrogen dose can often solve the problem. If the patient is not on OCPs, intermenstrual bleeding is usually due to a structural or inflammatory lesion. The differential diagnosis for anovulatory bleeding is extensive. Pregnancy, systemic illnesses, and structural lesions should be ruled out by history, physical examination, and laboratory evaluation. Endometrial biopsy is indicated in patients over age 35 and younger patients with risk factors for endometrial cancer, such as chronic anovulation and obesity. Dysfunctional uterine bleeding is a nonspecific term for abnormal uterine bleeding in the absence of systemic or structural disease. It is usually associated with anovulation. Adolescents frequently have dysfunctional uterine bleeding owing to immaturity of the hypothalamic-pituitary-ovarian axis. Perimenopausal women have an increased incidence of irregular bleeding secondary to decreased estrogen production by the ovary. Obesity, polycystic ovary syndrome, stress, crash diets, and vigorous exercise can all disrupt normal ovulatory function. Treatment options for dysfunctional uterine bleeding include oral contraceptives, cyclic progesterone, or hormone replacement with estrogen and progesterone. Patients with structural lesions or those who do not resume normal withdrawal bleeding patterns on hormone therapy should be referred to a gynecologist for further evaluation and treatment.

Adolescent↗

Nurse executives: leadership motivation and leadership effectiveness.

In a mailed survey, chief nurse officers (N = 92) described their leadership motivation and leadership effectiveness. Leadership motivation scores depicted high needs for affiliation and moderate needs for power. Leadership effectiveness scores reported by chief nurse officer and chief executive officer (n = 59 pairs) were correlated positively. Significant predictors of leadership effectiveness were job satisfaction, education, professional recognition, and experience, respectively. Those motivated by socialized power needs were in the most complex hospitals, whereas those motivated by affiliation were in the least complex settings. Identification of the motivational needs of successful leaders and aspiring leaders is advocated to provide valid and reliable measures for use in assessment centers and to inform curricula.

Educational Status↗

Personality characteristics of young adult offspring of substance abusers: a study highlighting methodological issues.

Our study sought to demonstrate the importance of attending to methodological issues in the study of personality characteristics of offspring of substance abusers (OSAs). A 4 x 2 factorial design, Parental Mental Health (no known psychological problems, substance abuse, other psychological problems, or dual diagnosis) x Exposure to Abuse/Neglect (present or absent), was used to examine depression proneness, neuroticism, alexithymia, self-esteem, self-concept, and locus of control in young adults. Results of this study demonstrated that in order to determine whether characteristics of OSAs are uniquely related to parental substance abuse, a psychiatric control group is needed. Also, the importance of separating the influences of other family environment variables (e.g., exposure to abuse/neglect) was demonstrated. None of the differences between groups in this study could be attributed to parental substance abuse per se; rather, the concomitants of substance abuse (i.e., exposure to abuse/neglect) were found to be more strongly related to poorer adjustment in OSAs. Finally, it was shown that the proportion of treatment-seeking subjects included in the sample affected the level of pathology observed. These results are discussed in relation to previous findings, and recommendations regarding methodology are made for future studies.

Adult↗

Immunological and biochemical characterization of cytochromes P-450 in mullet (Mugil cephalus): comparison with rainbow trout P-450s.

Immunoblots (Western blot) of mullet liver microsomes revealed the presence of multiple forms of P-450 that appear to be structurally related to rainbow trout CYP1A1 and CYP2K1 and to P-450 LMC1 and LMC4, but not to LMC5. 3-Methylcholanthrene but not beta-naphthoflavone induced a major 58 kDa liver protein and a minor 56 kDa protein in mullet that both cross-reacted with anti-trout CYP1A1 IgG. The levels of immunodetectable P-450s and the activities of microsomal lauric acid hydroxylase, DMBA hydroxylase and progesterone 6 beta-hydroxylase were several times lower in mullet liver than in rainbow trout liver; however, progesterone 16 alpha-hydroxylase and progesterone 20 alpha-hydroxylase activities were 4-fold and 6-fold higher, respectively, in mullet than in trout liver.

Animals↗

Measuring managerial motivation: the Power Management Inventory.

Psychometric properties for Part I of the Power Management Inventory (Hawker & Hall, 1981) are presented following validation of the instrument with samples of nurse managers (N = 54) and executives (N = 92). The content validity indices were .85 for management issues (item stems), .65 for Personalized Power (PP), .75 for Socialized Power (SP), and .70 for Affiliative Motive (AM) scales. Internal consistency reliabilities were acceptable (.63 to .87). Test-Retest correlations (n = 19 managers) ranged from .74 to .85. Correlation of nurse manager (n = 50) scores with subordinate scores of managers were significant (p < .05) for PP (r = .32) and AM (r = .29). Correlation of nurse executive (n = 59) scores with chief executive officer scores of executives were significant for PP (r = .32, p < .01) and AM (r = .25, p < .05). Mean scores of PP, SP and AM failed to profile the motive pattern for "successful" managers. About 29% of the managers and 39% of the executives were categorized as having no power motive preference. Use of the PMI for career counseling/decisions in nursing is not recommended, however, its use as an organizational development tool is endorsed.

Humans↗

Comparative effects of the polychlorinated biphenyl mixture, Aroclor 1242, on porphyrin and xenobiotic metabolism in kidney of Japanese quail and rat.

1. Aroclor 1242 (500 mg/kg, p.o.) produced a marked increase in porphyrin content of quail kidney (1800-fold), and of rat kidney but to a lesser extent (6-fold). 2. delta-Aminolevulinic acid synthetase activity was increased 12-fold in quail kidney but was unchanged in rat kidney following Aroclor 1242 treatment. 3. Uroporphyrinogen decarboxylase activity was significantly inhibited in quail kidney but not in rat kidney. 4. Renal ethoxyresorufin O-deethylase activity was induced in rat and quail whereas renal ethoxycoumarin O-deethylase and glutathione S-transferase activities were induced only in rats by Aroclor 1242.

5-Aminolevulinate Synthetase↗

Differential effects of 3,4,5,3',4',5'-hexachlorobiphenyl (HCB) on interrenal steroidogenesis in male and female rainbow trout Oncorhynchus mykiss.

1. The conversion of progesterone to 17 alpha-hydroxyprogesterone (17 alpha-OHP), 11-deoxycortisol (11-DOCR) and deoxycorticosterone (DOC) was significantly higher in female rainbow trout than in male trout; in contrast, the interrenal production of cortisol (CR) plus cortisone (CN) was higher in males than in females. 2. Following treatment with 1 mg/kg of HCB, the interrenal conversion of progesterone to 17 alpha-OHP and 11-DOCR was significantly increased in male and female trout but at 20 mg/kg of HCB, the production of these metabolites was increased in males and decreased in females; CR+CN production was unchanged after HCB treatment in both sexes.

17-alpha-Hydroxyprogesterone↗

Microsomal formation of a pyrrolic alcohol glutathione conjugate of the pyrrolizidine alkaloid senecionine.

1. Pyrrolizidine alkaloids (PAs) are metabolized primarily to putative dehydroalkaloid (PA pyrrole) metabolites and to PA N-oxide by rat liver microsomal monooxygenases. 2. The dehydroalkaloids are highly reactive and either bind covalentely to tissue nucleophiles or are hydrolysed to the more stable pyrrole, (R,S)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP), and the corresponding necic acid. 3. Addition of glutathione (GSH 1 mM) to incubation mixtures containing rat liver microsomes and the PA senecionine (SN), resulted in the formation of a conjugate of DHP with GSH. 5. The mass spectrum of this DHP-GSH conjugate was identical to that of the chemically-synthesized dehydroretronecine (the R enantiomer of the racemic DHP) and GSH. 6. Only negligible amounts of DHP-GSH conjugate were formed when DHP itself was incubated with GSH at physiological pH. 7. These findings provide strong evidence for the microsomal conversion of SN to a highly reactive metabolite, presumably dehydrosenecionine, which then reacts with GSH to form the DHP-GSH conjugate. 8. It is likely that a similar mechanism is responsible in vivo for the formation of GSH conjugates of DHP from SN and other PAs.

Alcohols↗

Flavin-containing monooxygenase: a major detoxifying enzyme for the pyrrolizidine alkaloid senecionine in guinea pig tissues.

Evidence based on optimal pH, thermal stability, and enzyme inhibition data suggests that the NADPH-dependent microsomal N-oxidation of the pyrrolizidine alkaloid senecionine is carried out largely by flavin-containing monooxygenase in guinea pig liver, lung, and kidney. In contrast, the hepatic microsomal conversion of senecionine to the pyrrole metabolite (+/-)-6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP) is catalyzed largely by cytochrome P450. However, the rate of senecionine N-oxide formation (detoxication) far exceeded the rate of DHP formation (activation) in guinea pig liver microsomes over a range of pHs (pH 6.8 to 9.8). In guinea pig lung and kidney microsomes, N-oxide was the major metabolite formed from senecionine with little or no production of DHP. The high rate of detoxication coupled with the low level of activation of senecionine in liver, lung, and kidney may help explain the apparent resistance of the guinea pig to intoxication by senecionine and other pyrrolizidine alkaloids.

Animals↗

Comparison of rainbow trout and mammalian cytochrome P450 enzymes: evidence for structural similarity between trout P450 LMC5 and human P450IIIA4.

Studies were undertaken to determine the immunochemical relationship between constitutive trout cytochrome P450s and mammalian cytochrome P450IIIA enzymes. Polyclonal antibodies (IgG) generated against trout P450 LMC5 reacted strongly with P450IIIA1 in dexamethasone-induced rat liver microsomes and with P450IIIA4 in human liver microsomes in immunoblots. In contrast, rabbit anti-P450 LMC1 IgG did not recognize these proteins in rat and human liver microsomes. Reciprocal immunoblots using anti-rat P450IIIA1 showed that this antibody does not recognize trout P450 LMC1 or LMC5. However, anti-human P450IIIA4 IgG was found to cross react strongly with P450 LMC1 and LMC5. Progesterone 6 beta-hydroxylase activity of trout liver microsomes, a reaction catalyzed by P450 LMC5, was markedly inhibited by anti-P450IIIA4 and by gestodene, a mechanism-based inactivator of P450IIIA4. These results provide evidence for a close structural similarity between trout P450 LMC5 and human P450IIIA4.

Animals↗

An interactive perspective on the health beliefs & practices of rural elders.

1. In this study, major themes involving health were closely tied to an affective response of "feeling good" and cognitive appraisal of health status as "being able to function." 2. Rural elderly who participated in the study reported engaging in at least one activity to maintain their health and tended to rely on their own appraisal and resources to manage health problems. 3. Half of the participants indicated a need for services such as blood pressure and diabetic screening, health education classes on diet, cholesterol reduction, hypertension and diabetes management, new therapies in health care, and life management counseling.

Aged↗

MMPI profile subtypes of incarcerated sex offenders against children.

Sex offenders are heterogeneous in personality and behavioral characteristics. The present study was conducted to identify homogeneous subgroups of incarcerated sexual offenders against children on the basis of the Minnesota Multiphasic Personality Inventory (MMPI). Subjects were 90 men undergoing initial evaluation for a treatment program conducted through a state department of corrections. Hierarchical cluster analysis resulted in the identification of four profile subgroups. While two subgroups presented mean profiles within normal limits, the patterns indicated differences in personality functioning: one presenting signs of sociopathy and the other emotional disturbance. In contrast, the other two profile subgroups presented several scale elevations: One subgroup indicated anger and aggression and the other severe psychopathology. Both of the latter subgroups were similar to two rapist subtypes identified in previous research. Subgroups were further differentiated on the basis of psychosexual, affective, and psychosocial variables. Results suggest the existence of homogeneous subgroups of incarcerated sexual offenders against children as delineated by the MPPI.

Adult↗

Regiospecificity in the hydroxylation of lauric acid by rainbow trout hepatic cytochrome P450 isozymes.

The catalytic activity of two hepatic cytochrome P450 isozymes from untreated rainbow trout towards lauric acid was investigated. In a reconstituted system, cytochrome P450 LMC1 and P450 LMC2 were found to catalyze exclusively the omega- and (omega-1)-hydroxylation of lauric acid, respectively. Microsomal enzyme inhibition studies with polyclonal antibodies raised against the individual P450 isozymes showed that P450 LMC1 and LMC2, respectively, accounted for most if not all the omega- and (omega-1)-lauric acid hydroxylase activity of trout liver microsomes. The polyclonal antibodies were highly specific in that they only inhibited the enzyme activity of the P450 used as the immunogen. These results illustrate that as in mammals, omega- and (omega-1)-hydroxylation of lauric acid by trout liver microsomes can be carried out separately by distinct isozymes of cytochrome P450.

Animals↗