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Biomedical subjects

D N Cox

Publications and source records attributed to D N Cox.

At least 37 records · Page 2Linked to original sources
PubMed1991

The relationship between self-efficacy and depression in adolescents.

This study examined the self-efficacy status of depressed versus nondepressed adolescents. As predicted, self-efficacy was negatively correlated with depression. A three-way interaction of Sex x Age x Level of Depression suggested separate analyses for males and females. Regression analysis revealed age-related changes in the dependence of depression scores on general, academic, physical and social self-efficacy status. It was concluded that self-efficacy has an important relationship with adolescent depression. The implications of these findings are discussed.

Adolescent↗
PubMed1990

The prevalence of depression in high school students.

In response to the need expressed in the literature on adolescent depression, recent studies have examined the incidence of affective disorders. However, there continues to be a paucity of research on the prevalence of depressive symptomatology in nonpatient adolescents. The Canadian literature is especially lacking in this area. The present study examined the prevalence of depression in a sample of 366 Canadian high school students. Consistent with similar research in the United Kingdom and the United States, 31.4% of the sample were midly to clinically depressed as measured by the Beck Depression Inventory. Significant sex differences were found; these are discussed in the context of age and level of depression. The need for further research on adolescent depression is emphasized.

Adolescent↗
PubMed1990

The Millon Adolescent Personality Inventory profiles of depressed adolescents.

The evidence indicates that adolescent depression may be more difficult to recognize than its adult counterpart, although the reasons for this difficulty remain unclear. The research in this area is in part impeded by the lack of adolescent-specific measures of personality functioning. In this study the personality styles, expressed concerns, and behavioral tendencies of depressed adolescents were investigated by means of the Millon Adolescent Personality Inventory (MAPI), a relatively new personality inventory designed specifically for this age group. Three hundred sixty-six high school students completed the Beck Depression Inventory (BDI) and the MAPI, resulting in 332 valid and reliable MAPI profiles. The data were reduced to two factors, accounting for 65.1% of the total variance, by means of a principal components analysis. The two factors were interpreted as two dimensions of personality functioning associated with depression in adolescents. The first dimension suggested a socially withdrawn, overtly recognizable depression, whereas the second presents acting-out tendencies that may overshadow depressive symptomatology. The findings are integrated with the theoretical positions represented in the literature. Theoretical and practical implications for the use of the MAPI with depressed adolescents are discussed.

Adolescent↗
PubMed1989

30-day oral toxicity study of L-selenomethionine in female long-tailed macaques (Macaca fascicularis).

Twenty female long-tailed macaques received nasogastric intubation of 0-600 micrograms/kg-day L-selenomethionine for up to 30 consecutive days. Selenium ingestion was well tolerated at all dose levels until the second to third week of the study at which time two animals given 600 micrograms/kg-day died. One animal from the 300 micrograms/kg-day group was removed from study on Treatment Day 19 due to selenium-induced hypothermia. In some cases, administered doses were reduced at the 300 and 600 micrograms/kg-day levels such that the final time-weighted average doses were 0, 25, 62-117, 150, 188-203, and 300 micrograms/kg-day. Six animals at the 188 micrograms/kg-day level or greater required nonscheduled fruit and dietary supplementation to prevent their impending demise. As the dose and duration of exposure increased, the incidence of anorexia, gastrointestinal distress, mucocutaneous toxicity, and frequency of reduced body temperature also increased. A dose-dependent reduction in body weight was also observed. At the greater doses, disturbances in menstrual function were evident, and were accompanied by the absence of serum progesterone concentrations above 1.0 ng/ml, reduced luteal phase lengths, increased intermenstrual intervals, and lowered estrogen excretion. A maximum tolerated dose of 150 micrograms/kg-day L-selenomethionine for 30 days was identified based on mean body weight reduction, hypothermia, dermatitis, xerosis, cheilitis, disturbances in menstruation, and the necessity of dietary intervention to prevent death at doses of 188 micrograms/kg-day or greater.

Animals↗
PubMed1989

Nephrotoxicity of para-substituted thiobenzamide derivatives in the rat.

Histological examination, plasma urea nitrogen levels (BUN), and renal cortical slice uptake of paminohippurate (PAH) or tetraethylammonium (TEA) were used to assess the nephrotoxicity of thiobenzamide and its para-substituted derivatives in Sprague-Dawley rats. Intraperitoneal injection of p-methylthiobenzamide (PMTB) to rats resulted in dose-dependent nephrotoxicity as judged by increased BUN levels, decreased TEA uptake and histologic examination of the kidney. Para-methoxythiobenzamide and PMTB were more potent nephrotoxins than thiobenzamide, which was itself minimally nephrotoxic. Para-methylthiobenzamide-S-oxide (PMTBSO) was more nephrotoxic than PMTB. Rats were pretreated with 1-methyl-1-phenylbenzoylthiourea (MPBTU), a non-toxic arylthiourea which inhibits the metabolism and toxicity of thiocarbonyl compounds. The nephrotoxicity and hepatotoxicity of PMTB was reduced by treatment with MPBTU 30 min prior to PMTB. Pretreatment with MPBTU protected against the renal toxicity of PMTBSO. The results indicate that electron donating para-substituted thiobenzamides produce dose-dependent renal injury, dependent upon oxidative biotransformation.

Amides↗
PubMed1988

A comparison of chorionic villi sampling and amniocentesis: acceptability of procedure and maternal attachment to pregnancy.

Sixty-one women with high-risk pregnancies participated in a clinical trial comparing chorionic villi sampling and amniocentesis. They were assessed initially on five background measures and maternal attachment to the fetus, then were randomly assigned to either chorionic villi sampling or an amniocentesis group. Women were further assessed for maternal attachment three times during pregnancy. During the final assessment, those who were planning future pregnancies were asked which of the two procedures they would prefer. No differences between groups were found on any of the five background measures. All 31 women who considered future pregnancies indicated a preference for chorionic villi sampling, regardless of the procedure they underwent during the study. Women receiving chorionic villi sampling reported significantly greater attachment during the second trimester than did women receiving amniocentesis, who viewed themselves as being less attached than other pregnant women during this period. The findings were interpreted as evidence for attachment suppression among women undergoing amniocentesis.

Amniocentesis↗
PubMed1987

Comparison of the toxicity of methylcyclopentadienyl manganese tricarbonyl with that of its two major metabolites.

Pneumotoxicity and lethality resulting from administration of methylcyclopentadienyl manganese tricarbonyl (MMT) and its 2 major metabolites in rats were compared. Following i.p. injection, MMT was found to have an LD50 value of 12.1 mg/kg. Neither of the metabolites appeared to have significant acute toxicity even when doses as high as 250 mg/kg were given. This impressive difference in toxicity may be due in part to changes in solubility of the metabolites, allowing for (1) decreased distribution into the central nervous system, coupled with (2) a more rapid excretion rate. This suggests that the oxidative metabolism of MMT that results in the formation of these metabolites is an important detoxifying pathway.

Animals↗
PubMed1987

Emotional responses of pregnant women to chorionic villi sampling or amniocentesis.

Seventy-four "high-risk" pregnant women interested in participating in a clinical trial comparing chorionic villi sampling and amniocentesis were initially assessed on five background measures and for anxiety, depression, hostility, and concern about abortion. The 61 women who then agreed to be randomized into the chorionic villi sampling and amniocentesis groups were assessed three additional times between 9 and 22 weeks' gestational age. Physical discomfort experienced during the diagnostic procedure was also assessed. Women in the chorionic villi sampling group underwent a reduction in anxiety up to 10 weeks earlier and reported less procedure-related discomfort than women in the amniocentesis group. The group X time interaction for depression was also significant, with women undergoing chorionic villi sampling reporting an earlier decrease in depression than women undergoing amniocentesis. No differences were found between the two groups in hostility or concern about abortion. Findings were discussed in the context of evidence linking prenatal maternal emotionality to an increased risk of obstetric complications.

Amniocentesis↗
PubMed1987

The psychological impact of diagnostic ultrasound.

The psychological impact of ultrasound scanning in pregnancy was examined in low- and high-risk pregnancies. Women in each category were assigned consecutively to a condition of either low or high feedback. In the latter condition, the women received extensive verbal and visual feedback, whereas in the former, subjects were denied visual access to the monitor. Psychological changes were measured using the State Anxiety Inventory and the Subjective Stress Scale. When a male partner attended, he was included in the assessment. The emotional impact of ultrasound was influenced by the level of feedback provided, with those in the high-feedback condition indicating significantly less anxiety and more positive emotional experiences during the scan, compared with those who received less feedback.

Adult↗
PubMed1984

Psychological changes over the course of pregnancy: a study of attitudes toward the fetus/neonate.

Pregnant women's attitudes towards their fetus over the course of the pregnancy were studied in relation to physiological events of pregnancy, namely seeing the fetus via ultrasound and experiencing fetal movement. A consecutive series of primiparae (n = 129) was randomly assigned, at recruitment between 10 and 14 weeks menstrual age, to conditions of high (n = 67) or low (n = 62) feedback real time ultrasound. Thereafter, women were assessed at 16 and 32 weeks gestation, within 24 hours of delivery and by questionnaire at 3 months postpartum. On each occasion women completed attitude rating scales concerning their pregnancy and their fetus or neonate. These scales were subjected to principal components analysis and two main dimensions were derived for ratings of both attitudes towards the pregnancy and the fetus/neonate. No relationship was found between factor scores and ultrasound feedback condition, although scores on the fetal attachment dimension showed a significant linear increase over the pregnancy. Women reporting fetal movement at 16 weeks displayed significantly higher scores on the fetal-attachment dimension at all three assessment points. Multiple regression analyses were utilized to identify predictors of initial reactions to the neonate and attachment ratings at 3 months postpartum. At delivery, ratings of attachment to the neonate were related to drug requirements in labor and attachment ratings at 32 weeks. Reactions to the neonate at delivery and ratings of postpartum mood emerged as significant predictors of maternal attachment at 3 months postpartum. These results are discussed in the context of research attempting to establish the importance of postpartum bonding.

Adolescent↗
PubMed1983

Properties of F1-ATPase from the uncD412 mutant of Escherichia coli.

Properties of purified F1-ATPase from Escherichia coli mutant strain AN484 (uncD412) have been studied in an attempt to understand why the amino acid substitution in the beta-subunit of this enzyme causes a tenfold reduction from normal MgATP hydrolysis rate. In most properties that were studied, uncD412 F1-ATPase resembled normal E. coli F1-ATPase. Both enzymes were found to contain a total of six adenine-nucleotide-binding sites, of which three were found to be non-exchangeable and three were exchangeable (catalytic) sites. Binding of the non-hydrolysable substrate analogue adenosine 5'-[beta gamma-imido]triphosphate (p[NH]ppA) to the three exchangeable sites showed apparent negative co-operativity. The binding affinities for p[NH]ppA, and also ADP, at the exchangeable sites were similar in the two enzymes. Both enzymes were inhibited by efrapeptin, aurovertin and p[NH]ppA, and were inactivated by dicyclohexylcarbodi-imide, 4-chloro-7-nitrobenzofurazan and p-fluorosulphonyl-benzoyl-5'-adenosine. Km values for CaATP and MgATP were similar in the two enzymes. uncD412 F1-ATPase was abnormally unstable at high pH, and dissociated into subunits readily with consequent loss of activity. The reason for the impairment of catalysis in uncD412 F1-ATPase cannot be stated with certainty from these studies. However we discuss the possibility that the mutation interrupts subunit interaction, thereby causing a partial impairment in the site-site co-operativity which is required for 'promotion' of catalysis in this enzyme.

4-Chloro-7-nitrobenzofurazan↗
PubMed1983

Integration of F1 and the membrane sector of the proton-ATPase of Escherichia coli. Role of subunit "b" (uncF protein).

Membranes derived from the Escherichia coli strain AN1460 which carries the multicopy plasmid pAN45 (unc+) (Downie, J. A., Langman, L., Cox, G. B., Yanofsky, C., and Gibson, (1980) J. Bacteriol. 143, 8-17) were enriched 5- to 10-fold in proton-ATPase activity. Incubation of F1-depleted AN1460 membranes with trypsin abolished F1-binding ability but did not inhibit proton transport through the membrane sector (F0). Sodium dodecyl sulfate-gel electrophoresis indicated that subunit "b" (uncF protein) of F0 was cleaved by trypsin and prebound F1 protected against the trypsin effect. Subunits "a" (uncB protein) and "c" (uncE protein) were unaffected by the trypsin treatment. A water-soluble fragment (Mr = 14,800) was liberated after trypsin treatment and appeared to arise from subunit b. Studies of enzyme hybridization and of F1 binding to membranes derived from strains containing mutations in uncB, F, and E genes supported the suggestion that subunit b is involved in F1 binding to the F0. Also, extraction of membranes with KSCN increased the relative proportion of subunit b in the membrane and this coincided with a parallel increase in trypsin-sensitive F1-binding ability. It is proposed that subunit b is involved in binding of F1 to the F0; this agrees with the presumed role of the protein as deduced from predictions of its secondary and tertiary structure (Walker, J. E., Saraste, M., and Gay, N. J. (1982) Nature (Lond.) 298, 867-869; Senior, A. E. (1983) Biochim. Biophys. Acta, in press).

Adenosine Triphosphatases↗
PubMed1982

How women view postepisiotomy pain.

Episiotomy is one of the most commonly performed operative procedures and yet little information is available on the subjective reactions in the puerperium to this procedure. The present study was designed to furnish information on the attitudes of patients, levels of pain, and of course recovery by studying a consecutive series of 101 Caucasian primiparea who received episiotomies at delivery. Women were interviewed within 24 hours of delivery and then, at three months after delivery, completed a questionnaire. The high level of pain experienced was noteworthy. Labour pain and episiotomy pain were uncorrelated, indicating the importance of distinguishing between them. Several women were experiencing problems at the three-month follow-up, with some attributing these to the episiotomy repair. The data are presented in the framework of providing women in the postpartum period with systematic information on the nature of postepisiotomy pain and subsequent recovery to facilitate their adjustment.

Activities of Daily Living↗
PubMed1982

The effects of ultrasound examination on maternal anxiety levels.

A study has been conducted to assess the psychological effects of real-time ultrasound on the pregnant woman's attitudes and anxiety levels. A consecutive series of primiparae, fulfilling the selection criteria of obstetrically "low risk," was assigned at random to two conditions of ultrasound, namely, (a) high feedback (N = 67), where the woman saw the moving fetus in utero; and (b) low feedback (N = 62), where the monitor screen was not visible and no specific feedback was provided. A third group of women was assessed following a wait period in order to compare state anxiety levels among the three groups. Attitude assessments showed consistent preultrasound-post-ultrasound change, with more uniformly positive attitudes displayed by the high-feedback group. No between-group differences in state anxiety emerged as a result of ultrasound compared with a wait control period. No differences emerged with respect to anticipatory anxiety measures. The results are considered in the context of evidence on the importance of psychological state on the course and outcome of pregnancy. It is suggested that the low-risk characteristics of this sample may have precluded effects on anxiety and it is concluded that the therapeutic potential of ultrasound warrants further study.

Adult↗
PubMed1982

A survey of patient attitudes towards artificial insemination by donor.

The psychological characteristics of a consecutive series (n = 58) of women attending an AID clinic have been examined. Women were assessed prior to treatment on a number of attitudinal and acceptability measures, as well as required to complete personality and martial adjustment inventories. At the time of each insemination, over 6 successive cycles, state anxiety was assessed. Following an interval of 6 months women were reassessed on an acceptability measure. The results showed generally positive attitudes at the outset. No systematic trends in anxiety were identified, with no differences between women becoming pregnant and those continuing in treatment. At follow-up women acknowledged the strain involved in timing the insemination to coincide with ovulation, with both pregnant and nonpregnant women attributing outcome to their psychological and emotional state at the time. The implications of these results are considered in terms of the characteristics of women requesting AID and the ways in which clinics can attend to the psychological states of the patients.

Adult↗