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Biomedical subjects

J Davila

Publications and source records attributed to J Davila.

At least 19 recordsLinked to original sources
PubMed1999

Attachment change processes in the early years of marriage.

The authors examined 4 models of attachment change: a contextual model, a social-cognitive model, an individual-difference model, and a diathesis-stress model. Models were examined in a sample of newlyweds over the first 2 years of marriage, using growth curve analyses. Reciprocal processes, whereby attachment representations and interpersonal life circumstances affect one another over time, also were studied. On average, newlyweds became more secure over time. However, there was significant within-subject variability on attachment change that was predicted by intra- and interpersonal factors. Attachment representations changed in response to contextual, social-cognitive, and individual-difference factors. Reciprocal processes between attachment representations and marital variables emerged, suggesting that these factors influence one another in an ongoing way.

Adaptation, Psychological↗
PubMed1999

Depression and Axis II symptomatology in an adolescent community sample: concurrent and longitudinal associations.

The relationship between personality pathology and depression has been the focus of increasing attention, but few investigators have examined this issue prospectively or in adolescent community samples. The present study used both self report and interviewer assessments of personality disorder symptomatology and depression in a sample of 155 late adolescent women followed over three years. Personality pathology cluster and total scores demonstrated moderate to fairly high degrees of stability, indicating endurance of these traits in late adolescence. As predicted, Axis II symptoms were associated with concurrent depressive symptomatology. Overall, self-reported personality disorder symptoms, as well as those specifically in Clusters A and B, predicted interviewer-rated depression over two years beyond the contribution of initial depression, indicating that subclinical Axis II symptoms are a risk factor for subsequent depressive symptomatology.

Adolescent↗
PubMed1998

Axis II symptomatology, depression, and life stress during the transition from adolescence to adulthood.

This study examined 2 models of the relationship between personality disorder symptomatology and depression, incorporating life stress as an intervening variable. In a community sample of late adolescent women, symptoms of Cluster B disorders predicted interpersonal chronic stress and self-generated episodic stress over 2 years, controlling for initial depression. Cluster A symptoms also predicted subsequent chronic interpersonal stress, over initial depression. Cluster C pathology did not predict subsequent stress. Personality disorder symptomatology was also associated with partner-reported relationship dissatisfaction. Support was found for a mediation model whereby women with higher levels of initial personality disturbance in Clusters A and B generated excessive amounts of episodic stress and interpersonal chronic stress in the next 2 years, which, in turn, increased vulnerability for depressive symptoms. A moderation model, whereby the presence of greater personality disorder symptoms would increase the likelihood of depression in response to stress, was not supported.

Adolescent↗
PubMed1997

The relationship between attachment cognitions and psychological adjustment in late adolescent women.

This longitudinal study of 137 female high school seniors investigated the relationship of attachment cognitions, current psychological functioning, and psychological functioning 12 months later. Attachment cognitions, assessed with the Revised Adult Attachment Scale and the Inventory of Parent and Peer Attachment, were significantly associated with current symptomatology. The Revised Adult Attachment Scale, in interaction with initial symptomatology, predicted depression, substance abuse, eating disorders, and personality disorders 12 months later. The Inventory of Parent and Peer Attachment parent subscales predicted eating disorder and personality disorder symptomatology, whereas the peer subscales predicted substance abuse, eating disorder, and personality disorder symptomatology.

Adaptation, Psychological↗
PubMed1997

Predictors of the generation of episodic stress: a longitudinal study of late adolescent women.

The effects of depression and Axis I comorbidity on subsequent self-generated life stress were examined in a longitudinal sample of 134 late adolescent women. The results indicated that specific forms of psychopathology constitute a risk factor for future self-generated episodic stress, even when controlling for prior chronic stress. Comorbid depression had a particularly salient effect in the prediction of stress related to interpersonal conflicts. The effects of family psychopathology and sociotropy were mediated through participant psychiatric status, whereas autonomy made an independent contribution to the prediction of episodic stress. These results support C. Hammen's (1991b) stress generation model in a community sample, demonstrating how individuals with depression play a role in the creation of stress, and also refine prior work by showing that only the comorbid form of depression is associated with subsequent conflict-related stress.

Adolescent↗
PubMed1997

Why does attachment style change?

Adult attachment research has proceeded on the assumption that attachment style is relatively stable and affects future functioning. However, researchers have become interested in attachment instability and predictors of attachment style change. In this article, 2 conceptualizations of attachment style change were examined: Attachment style change is a reaction to current circumstances, and attachment style change is an individual difference in susceptibility to change that is associated with stable vulnerability factors. A total of 155 women were assessed after high school graduation, and 6 months and 2 years later. Results primarily supported the conceptualization of attachment style change as an individual difference. Specifically, some women may be prone to attachment fluctuations because of adverse earlier experiences, and women who show attachment fluctuations are similar to women with stably insecure attachments.

Adaptation, Psychological↗
PubMed1997

Marital functioning and depressive symptoms: evidence for a stress generation model.

The present study applied C.L. Hammen's (1991) stress generation model to depressive symptoms in the context of marriage. The authors predicted that depressive symptoms would lead to increased marital stress, which would in turn lead to increased depressive symptoms. Social support processes were hypothesized to function as a mechanism by which dysphoric spouses generate stress. Hypotheses were tested in a sample of 154 newlywed couples. Depressive symptoms, marital stress, support perceptions, and support behavior (assessed using observational procedures) were assessed initially and 1 year later. Results provided evidence of marital stress generation among wives, and social support processes functioned as a mechanism of stress generation for wives. Results highlight the cyclical course of dysphoria and stress among wives.

Adult↗
PubMed1995

Poor interpersonal problem solving as a mechanism of stress generation in depression among adolescent women.

The authors examined C. Hammen's (1991) model of stress generation in depression and the role of interpersonal problem-solving strategies (IPS) in the stress generation process in a longitudinal sample of 140 young women who entered the study at ages 17-18. Structural equation modeling was used to test a model in which IPS and subsequent interpersonal stress mediated the relationship between initial and later depressive symptoms. Results supported the main prediction of the stress generation model: Interpersonal stress mediated the relationship between initial and later depressive symptoms. In addition, IPS predicted interpersonal stress. However, no association was found between depressive symptoms and IPS. An alternative model in which IPS moderated the relationship between stress and depressive symptoms was tested; it was not supported.

Adolescent↗
PubMed1995

Interpersonal attachment cognitions and prediction of symptomatic responses to interpersonal stress.

The authors tested a cognitive-interpersonal hypothesis of depression by examining the role of interpersonal cognitions in the prediction of depression associated with interpersonal stressors. A measure of adult attachment assessed interpersonal cognitions about ability to be close to others and to depend on others and anxiety about rejection and abandonment. Participants were women who had recently graduated from high school; they were followed for 1 year with extensive interview evaluation of life events, depression, and other symptomatology. Generally, cognitions, interpersonal events, and their interactions contributed to the prediction of interview-assessed depressive symptoms, but the effects were not specific to depression and predicted general symptomatology measured by diagnostic interviews as well, and results also varied by attachment subscale. Results were discussed in terms of a developmental psychopathology approach to disorders in young women.

Cognition↗
PubMed1992

Psychiatric history and stress: predictors of severity of unipolar depression.

Unipolar depression is frequently a recurrent or chronic disorder. In studies on predicting its course, outcomes are typically linked to either psychiatric features or stressful life events. In order to integrate the 2 approaches, 51 unipolar patients were assessed periodically over at least 1 year for symptoms, stressful events, and chronic stressors. It was hypothesized that adverse family history and early age of onset impair role functioning and coping capabilities, thereby contributing to stressful circumstances that predict severity of depressive reactions. Results of causal modeling analyses supported a model in which background factors were associated with severity of depressive outcomes as mediated by their effects on stress variables. Such a model implicates the self-perpetuating nature of clinical depression, both for the individual and across generations.

Adult↗
PubMed1991

Photochemistry of merocyanine 540: the mechanism of chemotherapeutic activity with cyanine dyes.

The photophysical properties of merocyanine 540 have been determined in methanol solution over a modest temperature range. Triplet state population is inefficient (the limiting triplet quantum yield being 0.25) due to rapid isomerization of the central double bond from the first excited singlet state. Activation energies have been measured for isomerization from the excited singlet state (20 kJ mol-1) and for conversion of the resultant cis-isomer back to the original trans-form (63 kJ mol-1), both processes involving formation of a twisted species. The dye is easily oxidized to give an unstable adduct which decomposes on the sub-ms timescale. Reversible redox chemistry occurs upon excitation in the presence of electron acceptors. These various observations are discussed in terms of the known chemotherapeutic activity of MC540 and it is concluded that the most probable mechanisms for cytotoxicity involve either local thermal disruption of cell membranes or in situ photogeneration of toxins derived from breakdown of the dye.

Molecular Structure↗
PubMed1990

Photoreactions of macrocyclic dyes bound to human serum albumin.

The photophysical properties of tetrakis(4-sulfonatophenyl)porphyrin (H2TSPP), its tin (IV) complex (SnTSPP), aluminium(III) trisulfonatophthalocyanine (AIPCS), and the corresponding zinc(II) complex (ZnPCS), have been measured in H2O, D2O, and upon binding to human serum albumin (HSA). The triplet excited states of the various macrocyclic dyes generate singlet molecular oxygen, O2(1 delta g) in high quantum yield upon illumination in O2-saturated solution, even in the presence of HSA. The triplet states also abstract an electron from 4-aminophenol, forming the radical anion of the macrocycle. Quenching rate constants and quantum yields have been measured for the various processes in the presence and absence of HSA. It is found that HSA binds all the dyes at nonspecific sites close to the interface in such a manner that the dyes remain accessible to species residing in the solution phase. Dyes that do not possess axial ligands complexed to the central cation (e.g. H2TSPP, ZnPCS) are able to bind also at a deeper, more specific site on the protein where they are protected from species in solution. Under such conditions, triplet quenching by 4-aminophenol is restricted to long-distance electron tunnelling, for which the rate is relatively slow.

Aluminum↗
PubMed1989

Photosensitized oxidation of biomaterials and related model compounds.

Aluminium trisulfonatophthalocyanine (A1PCS), a dye being widely advocated for use in photodynamic therapy, produces singlet oxygen with a quantum yield of 0.34 in oxygenated water at pH 7. Triplet A1PCS abstracts an electron from a variety of amines and phenols, the rate of electron transfer depending upon the thermodynamic driving force, forming the A1PCS radical anion. This latter species reduces molecular oxygen to superoxide ions with high efficiency. The triplet state also abstracts an electron from biological components, including NADH, vitamin C, cysteine, methionine, tyrosine, tryptophan, uracil, and guanine, but not from DNA. These results suggest that photoinduced electron abstraction from appropriate biomaterials could compete with singlet oxygen production under in vivo conditions.

Aminophenols↗
PubMed1984

Clonidine reduces elevated cerebrospinal fluid catecholamine levels in patients with essential hypertension.

Cerebrospinal fluid (CSF) catecholamines were measured in normotensive patients and in patients with mild to moderate essential hypertension. CSF-norepinephrine (NE) concentrations were 50% lower in the normotensive individuals (127 +/- 28 vs. 240 +/- 23 pg/ml) (P less than 0.01). In hypertensive patients, CSF-NE was inversely related to age (r = -0.68; P less than 0.01) and directly related to plasma NE (r = 0.61; P less than 0.05). Clonidine (450 mcg/day for 2 weeks) significantly reduced CSF-NE (-40%) in hypertensive patients. In addition, it decreased blood pressure, plasma and urinary NE. Urinary VMA was not affected by clonidine. No correlation was observed between clonidine effects on BP and on plasma or CSF catecholamines. This study indicates that patients with essential hypertension have elevated levels of CSF-NE which are reduced after treatment with clonidine. The elevation of CSF-NE suggests that central (spinal?) noradrenergic activity may be increased in patients with mild to moderate essential hypertension, and that can be reduced by treatment with clonidine.

Adult↗
PubMed1981

Toxicity with intravenous injection of crude marijuana extract.

Intravenous injection of crude marijuana extract led to development of an acute illness with multisystem involvement. Gastrointestinal manifestations consisted of severe vomiting, diarrhea, and crampy abdominal pain. Hypotension, tachycardia, and peripheral vasodilation constituted the main cardiovascular manifestations of the disease. Moderate azotemia and oliguria, presumed to be of prerenal origin, were present and rapidly resolved with administration of intravenous fluids. Hematologic manifestations consisted of leukocytosis with a left shift, thrombocytopenia, prolonged partial thromboplastin time, increased fibrin degradation products, and positive protamine sulfate test. The observed coagulation abnormalities may suggest intravascular coagulation. C3, C4, and total hemolytic complement were reduced, suggesting possible activation of the complement system. Hyperventilation, hypoxemia, pulmonary edema, obstructive, and restrictive pulmonary function abnormalities and bilateral pleural effusions highlighted the pulmonary manifestations of the disease. Rhadbomyolysis and mild hepatic function abnormalities were also present. All observed abnormalities reversed in a few days with no significant sequelae.

Adult↗
PubMedDate not supplied

Cerebrospinal fluid and plasma dopamine-beta-hydroxylase activity in human hypertension.

Cerebrospinal fluid (CSF) and plasma dopamine-beta-hydroxylase (DBH) activity was measured in 22 normotensive (NT), 31 essential hypertensive (EH), and 11 renal hypertensive (RH) patients. Although no differences were observed in their plasma DBH, the mean CSF-DBH activity and specific activity of EH were significantly lower than those of NT and RH patients. Very low CSF-DBH (less than 0.15 units/ml of CFS or less than 0.5 units/mg of CSF protein) was found only in EH (26% of EH). Of the 31 EH patients, 19(60%) had CSF-DHB activities lower than 0.5 units/ml, whereas only 5 of 22 NT (23%) and no RH fell within this range. Nevertheless, 20% of EH, 55% of NT, and 40% of RH patients had CSF-DBH activities above the mean value for NT (less than 0.9 units/ml). NT subjects with very low plasma DBH (less than 50 units/ml) had CSF-DBH activities that fell within normal range. With the exception of these subjects, the specific activity of CSF-DBH was always lower than that of the plasma enzyme. The concentration of albumin, alpha 1, beta, and gamma globulins was measured in plasma and CSF obtained from the last five NT, four EH, and two RH patients. A positive linear relationship was obtained when the log of the plasma/CSF concentration ratio for these proteins was plotted against their molecular weight. Similar slopes and intercepts were obtained for these patients, suggesting that no major differences seem to exist in their blood-brain-barrier permeability to proteins. The results suggest that measurements of CSF-DBH could be of help in the differential diagnosis of human hypertension and in the neurochemical characterization of EH. If CSF-DBH reflects central noradrenergic activity, its reduction might indicate the existence of a central catecholaminergic defect in a subgroup of EH patients.

Adolescent↗