Biomedical subjects

G Parker

Publications and source records attributed to G Parker.

At least 19 recordsLinked to original sources

PubMed2007

Osteochondritis dissecans of the knee; long-term clinical outcome following arthroscopic debridement.

We reviewed 32 knees in 26 patients who had previously undergone arthroscopic debridement for symptomatic osteochondritis dissecans (OCD) of the knee. The patients were followed up at a minimum of 11 years following surgery and were evaluated clinically using the American Knee Society Clinical Rating Score. Additional evaluation was performed using the Hughston Scale to include radiographic assessment. The mean American Knee Society Score was 179 (out of 200), indicating good clinical function. Radiographically, however, only 29% scored excellent or good on the Hughston Scale. Younger patients with a small, stable (and therefore preserved), medial femoral condyle lesion had the best prognosis. Whilst more novel and complex options such as chondrocyte implantation are being assessed for the treatment of OCD, it is clear that within this study group careful debridement with removal of loose tissue can achieve good clinical results in the long term. There was however radiographic evidence of early degenerative joint disease in 17/24 (71%) of patients reviewed. Patients undergoing excision of OCD fragments did worse than those in whom the fragment was preserved, however the risk of further surgery is raised if a fragment is left in situ at initial surgery.

Adolescent↗

PubMed2006

Is post-Lipiodol CT better than i.v. contrast CT scan for early detection of HCC? A single liver transplant center experience.

Hepatocellular carcinoma is a highly vascular neoplasm usually arising from a cirrhotic liver. Delayed, noncontrast, computed tomography (CT) imaging after 7 to 14 days reveals an oil-based contrast agent to be concentrated in the tumor but not in normal hepatic parenchyma. The aim of this study was to retrospectively correlate the post Lipiodol CT scan findings with respect to tumor size in the explanted liver. We retrospectively reviewed adult patients who had undergone orthotopic liver transplantation between November 1995 and December 2004 and also had an hepatic arteriogram with Lipiodol injection as part of their pretransplant workup. We calculated sensitivity, specificity, false-negativity, false-positivity, and accuracy of the test, as well as positive and negative predictive values. Lipiodol CT exam had sensitivity of 1.0; specificity of 0.6 with a calculated positive predictive value of 0.89 and a negative predictive value of 1.0. Overall accuracy of Lipiodol CT scan test was found to be 0.91, which was superior to an intravenous contrast CT alone. In conclusion, because of the higher sensitivity and accuracy values, hepatic arterial Lipiodol injection can be considered during the pretransplantation workup of high-risk cirrhotic patients, since the current model for End-stage Liver Disease scoring system for hepatocellular carcinoma is built on the ultimate bulk of the tumor. Further multicenter, controlled, large-volume prospective studies are warranted to verify this observation.

Adult↗

PubMed2006

Actions taken to cope with depression in patients seeking specialist care.

OBJECTIVE: To assess the rates and perceived effectiveness of actions used to cope with depression and the factors influencing these in an outpatient sample seeking help for depression. METHOD: One hundred and seventy-six patients (74 male, 102 female) aged 16-82 years (M = 42, SD = 14.4 years) with a major depressive episode (DSM-IV criteria) were assessed using a number of measures that covered sociodemographics, history of psychiatric illness, actions taken to alleviate depression and their perceived effectiveness. Logistic regression analyses assessed age, gender and illness characteristics associated with the use and perceived effectiveness of strategies adopted to manage depression. RESULTS: Medical interventions were used and perceived to be effective in alleviating depressive symptoms by most of the sample, as were self-help and complementary therapies. Sociodemographic and illness-related characteristics had a significant influence, with younger age and having experienced an episode of anxiety disorder found to be the strongest predictors for the use of coping strategies. Being female was the strongest predictor for their effectiveness. CONCLUSION: A range of actions for depression, including medical and complementary interventions, were used and found to be helpful in a sample that had sought professional help for depression. Gender, age, depression and anxiety factors were all found to predict the use and perceived effectiveness of these strategies.

Adaptation, Psychological↗

PubMed2005

Sleeping in? The impact of age and depressive sub-type on hypersomnia.

BACKGROUND: While early morning wakening is held to be a classic feature of melancholia, we investigate the clinical observation that young patients with melancholia and bipolar depression tend to be more likely to report hypersomnia. METHODS: We examine age-related rates of those two sleep disturbance patterns in a consecutive set of out-patients with differing depressive sub-types assessed over a 20-year period. RESULTS: Hypersomnia was more likely to be reported than early morning wakening across all age bands by those with non-melancholic depression. Hypersomnia was also more likely than early morning wakening in younger patients with melancholia and bipolar disorder but, with age, early morning wakening became the dominant pattern. LIMITATIONS: The study was retrospective, undertaken in a sample attending a tertiary referral unit and artefactual determinants of the associations were not pursued. CONCLUSIONS: We speculate that hypersomnia may be a non-specific homeostatic coping response to stress and thus to the non-melancholic depressive disorders, but that this pattern is overruled by an early morning wakening pattern in the more biological depressive sub-types as the individual ages, perhaps reflecting a noradrenergic contribution.

Adult↗

PubMed2005

Cranial venous outflow obstruction and pseudotumor Cerebri syndrome.

The pathophysiology of PTS including idiopathic intracranial hypertension or 'BIH', remains controversial. The older literature frequently referred to pathology in the cerebral venous drainage but more modern imaging techniques (CT and early MR) failed to reveal gross venous pathology. The role of impaired cranial venous outflow has recently been re-examined in the light of new methods of investigation (advanced MR venography and direct microcatheter venography with manometry) and of treatment (venous sinus stenting). Venous sinus obstruction in PTS is a more common factor in the pathogenesis of the condition than previously recognised. Venous obstruction may be primary, that is, it is the underlying aetiological factor in PTS. Venous sinus obstruction may also be secondary to raised CSF pressure which may exacerbate problems with intracranial compliance and raised CSF pressure. Early experience with venous stenting suggests that it may be a helpful treatment for patients with PTS but more experience and longer follow-up is required to define the subgroups of patients for whom it is most appropriate.

Cerebral Veins↗

PubMed2005

Reduced litter sizes following 48-h of prenatal exposure to 5 nT to 10 nT,0.5 Hz magnetic fields: implications for sudden infant deaths.

To test the hypothesis that a narrow intensity band of geomagnetic activity contributes to Sudden Infant Death, 32 pregnant rats were exposed for two to three days before expected parturition either to a coil that generated 0.5 Hz sine-wave, 5 to 10 nanoTesla magnetic fields, or to a reference coil (<1 nT) in the same room. The field was off for 30 min every 4 h during the exposure. The orientation of the coils was perpendicular in space and activated alternately in four blocks of experiments. The litters born to the exposed mothers contained significantly fewer pups (M = 14.1,SD= 2.1) than those exposed to the control conditions (M = 16.2, SD = 2.7). There were significantly fewer numbers of males and fewer numbers of females in litters exposed to the fields generated in the east-west and north-south directions, respectively. These results support the hypothesis that a specific temporal configuration of brief periods of geomagnetic activity can produce an increased incidence of nonvital fetuses, neonates, or infants.

Animals↗

PubMed2005

Self-harming in depressed patients: pattern analysis.

OBJECTIVE: As deliberate self-harm (DSH) is a common concomitant of depressive disorders, we undertook a study examining the relevance of possible determinants and correlates of DSH. METHOD: Three separate samples of depressed outpatients were studied to determine consistency of identified factors across samples, with principal analyses involving gender, age and diagnosis-matched DSH and non-DSH subjects. RESULTS: Across the samples, some 20% of subjects admitted to episodes of DSH. Women reported higher rates and there was a consistent trend for higher rates in bipolar patients. Univariate analyses examined the relevance of several sociodemographic variables, illicit drug and alcohol use, past deprivational and abusive experiences, past suicidal attempts and disordered personality functioning. Multivariate analyses consistently identified previous suicide attempts and high 'acting out' behaviours across the three samples, suggesting the relevance of an externalizing response to stress and poor impulse control. CONCLUSIONS: Results assist the identification and management of depressed patients who are at greater risk of DSH behaviours.

Adult↗

PubMed2005

Progressing a spectrum model for defining non-melancholic depression.

OBJECTIVE: To further develop a 'spectrum model' for non-melancholic disorders that encompasses underlying personality styles and clinical patterning. METHOD: In a sample of patients with non-melancholic depression, we studied four personality constructs influencing risk to depression, assessing associational strength and specificity between personality scores and symptom and coping response patterns. RESULTS: Analyses refined four personality dimensions (anxious worrying, irritability, social inhibition, and self-centredness) for testing the model. For all dimensions, personality style was specifically linked with a mirroring 'coping' response. Quantification of specific links allowed development of a spectrum model for the non-melancholic depressive disorders in which underpinning personality style showed some specific links with the clinical 'pattern' of symptoms and coping repertoires. CONCLUSION: The model has the capacity to assist clinical assessment, identify aetiological personality influences and allow specific treatment effects for the heterogeneous non-melancholic depressive disorders to be determined.

Adaptation, Psychological↗

PubMed2005

Antenatal screening for the prediction of postnatal depression: validation of a psychosocial Pregnancy Risk Questionnaire.

OBJECTIVE: To assess the predictive value of an antenatal index of risk for postnatal depression (PND). METHOD: Participants returned the Pregnancy Risk Questionnaire (PRQ; 18 antenatal items) and the Edinburgh Depression Scale (EDS) at a mean of 32 weeks gestation; the EDS was then mailed out at 2 and 4 months postpartum to ascertain those women who were screened positive (score>2), i.e. probable cases of depression. Only those returning the EDS at 2 and/or 4 months were included in the study (n=1296). Women who screened positive (n=322; 24.8%) were contacted and of these, 245 completed the Auto-Composite International Diagnostic Interview (CIDI) and form the basis of our primary analyses. RESULTS: A CIDI diagnosis of major depression was found in 5.3% women at either 2 or 4 months. In this population, the optimal PRQ cut-off was >or=46 at which point sensitivity was 44% and specificity 92%. At this cut-off 9.9% tested positive (for risk of PND) on the PRQ with a positive predictive value (PPV) of 23.5%. Of 1079 women who scored below 46 on the PRQ, 3.2% were cases of CIDI depression while of those 119 scoring 46 or above, 23.5% were CIDI cases at 2 or 4 months postpartum, yielding an odds ratio of 9.18. CONCLUSION: Using a cut-off of >or=46, the PRQ is better than previously reported tools in the antenatal prediction of PND with respect to sensitivity and specificity, while like other studies PPV remains limited. The PRQ allows identification of high and low risk groups and thus has applicability in both the research and clinical settings.

Adult↗

PubMed2004

Is the female preponderance in major depression secondary to a gender difference in specific anxiety disorders?

BACKGROUND: While a female preponderance in unipolar depression is a consistent finding in community-based studies, determinants remain speculative. This study aimed to examine whether a female preponderance in certain anxiety disorders drives a gender difference in depression. METHOD: The relevant data from the National Comorbidity Study (NCS) are analysed. RESULTS: We observed a biphasic pattern in the emergence of a female preponderance in the depressive and anxiety disorders, with an initial pre-pubertal or early adolescent onset, and after attenuation in early to middle adulthood, re-emergence in mid- to late-adulthood. Analyses focused on determinants of the initial female preponderance. Female gender, presence of an anxiety disorder and variable ages of onset in the anxiety disorder all contributed to the increased chance of an initial depressive episode. Some specificity in linking the onset of depressive temporally in early adolescence with two anxiety disorders was demonstrated, specifically generalized anxiety disorder and panic disorder. CONCLUSIONS: The separate anxiety disorders and their age of onset had variable links with depression, but female gender remained a significant predictor of depression after accounting for the effects of prior anxiety.

Adolescent↗

PubMed2004

Studies in NZB IL-10 knockout mice of the requirement of IL-10 for progression of B-cell lymphoma.

NZB mice develop an age-related malignant expansion of a subset of B cells, B-1 cells, with autocrine production of IL-10. IL-10, a pleiotropic cytokine with anti-inflammatory properties, is a potent growth and survival factor for malignant B cells. To further examine the in vivo requirement for IL-10 in the development and expansion of malignant B-1 clones in NZB mice, we developed a strain of homozygous IL-10 knockout (KO) mice on an NZB background. The NZB IL-10 KO mice develop peritoneal B-1 cells with approximately the same frequency as heterozygous and wild-type littermates. In contrast, the development of malignant B-1 cells in the peripheral blood and spleen, observed in wild-type NZB, rarely occurred in the NZB IL-10 KO. Phenotypic analysis of surface marker expression in splenic B cells indicated that, in contrast to the NZB with malignant B-1 splenic lymphoma, the surface marker expression of NZB IL-10 KO splenic B cells indicated that the majority of the B cells were typical B-2 cells. In the absence of IL-10, spontaneously activated B cells and antiapoptotic gene expression were reduced and lymphoma incidence was decreased. These results indicate that IL-10 is a critical factor for the progression of this B-cell malignant disease.

Animals↗

PubMed2004

Studying personality characteristics in bipolar depressed subjects: how comparator group selection can dictate results.

OBJECTIVE: To examine the extent to which identification of any distinct personality characteristics in bipolar subjects are influenced by selection of the comparison diagnostic group. METHOD: Scores were compared on several general measures of personality style and, additionally, the prevalence of disordered personality functioning was examined in a sample of 198 non-psychotic depressed subjects, 39 with bipolar depression and 159 with unipolar depression. RESULTS: When the bipolar subjects were separately compared with unipolar subjects, and to sub-sets of those with clinically and DSM-IV defined melancholic and non-melancholic depression, quite differing results were suggested. In essence, clinically-defined melancholic subjects had the least personality psychopathology in comparison with the non-melancholic and bipolar subjects. CONCLUSION: Whether subjects with bipolar disorder have any distinct personality characteristics or over-represented co-morbid personality disorders remains quite unclear when reference is made to the literature. We suggest that inconsistencies across studies may reflect choice and representation of depressive sub-types within the unipolar comparator group.

Adult↗

PubMed2004

ZD9331 as second- or third-line therapy in patients with advanced colorectal cancer: a phase II multicenter trial.

This study investigated the efficacy and tolerability of ZD9331 as second- or third-line treatment for patients with advanced colorectal cancer (aCRC). One hundred patients were recruited to the study: 45 in group 1 (failed first-line 5-FU-based regimen) and 55 in group 2 (failed first-line 5-FU-based regimen and second-line irinotecan). Patients received ZD9331 as a 30-minute intravenous infusion on days 1 and 8 of a 3-week cycle, and treatment continued until disease progression (PD) or withdrawal. After a median of 4 cycles of treatment, there were no objective responses in group 1 (N = 37), 25 (67.6%) patients had a best overall response of stable disease (SD), and 12 (32.4%) had PD. After a median of 3 cycles of treatment, there were 2 (4.5%) partial responses in group 2 (N = 44), 21 (47.7%) patients had a best overall response of SD, 20 (45.4%) had PD, and 1 (2.3%) had clinical progression. At data cut-off, 59.5% and 77.3% of patients in groups 1 and 2, respectively, had PD. The main adverse events were neutropenia (69%), fatigue (53%), nausea (46%), and diarrhea (40%), and most (72.3%) were grade I/II. ZD9331 demonstrated minimal antitumor activity, and manageable toxicity, in the second- or third-line treatment of aCRC.

Adult↗

PubMed2004

Measuring disordered personality functioning: to love and to work reprised.

OBJECTIVE: Current limitations to diagnosing and measuring the personality disorders encouraged a set of studies seeking to provide an alternate approach to modeling and measuring disordered personality function. METHOD: A large set of self-reported descriptors of disordered personality function were factor analyzed in a sample of patients with clinician-diagnosed personality dysfunction, generating 11 lower-order and two higher-order constructs. Subjects and non-clinical controls also completed a measure of personality styles underpinning formalized personality disorder groupings. Properties of the refined self-report (SR) measure were assessed in an independent sample of patients with a clinically diagnosed personality disorder. RESULTS: Limitations in 'cooperativeness' and 'coping' formed the higher-order constructs defining disordered personality function, with these constructs relevant to all personality styles. Analyses of SR, corroborative witness (CW) and clinician-rated data in an independent sample supported measuring disordered personality function by our derived 20-item SR measure, and exposed limitations to clinician-based assessment. CONCLUSION: Study findings build to a multi-axial strategy for measuring personality disorder, involving separate dimensional assessment of both disordered personality function and of personality style.

Adaptation, Psychological↗

PubMed2004

Geophysical variables and behavior: XCIX. Reductions in numbers of neurons within the parasolitary nucleus in rats exposed perinatally to a magnetic pattern designed to imitate geomagnetic continuous pulsations: implications for sudden infant death.

Correlational analyses have shown a moderate strength association between the occurrence of continuous pulsations, a type of geomagnetic activity within the 0.2-Hz to 5-Hz range, and the occurrence of Sudden Infant Deaths. In the present study, rats were exposed continuously from two days before birth to seven days after birth to 0.5-Hz pulsed-square wave magnetic fields whose intensities were within either the nanoTesla or microTesla range. The magnetic fields were generated in either an east-west (E-W) or north-south (N-S) direction. At 21 days of age, the area of the parasolitary nucleus (but not the solitary nucleus) was significantly smaller, and the numbers of neurons were significantly less in rats that had been exposed to the nanoT fields generated in the east-west direction or to the microTesla fields generated within either E-W or N-S direction relative to those exposed to the N-S nanoTesla fields. These results suggest nanoTesla magnetic fields, when applied in a specific direction, might interact with the local geomagnetic field to affect cell migration in structures within the brain stem that modulate vestibular-related arousal and respiratory or cardiovascular stability.

Animals↗

PubMed2003

Gender differences in response to differing antidepressant drug classes: two negative studies.

BACKGROUND: A recent US study presented data suggesting that depressed women are more likely to respond to selective serotonin reuptake inhibitor (SSRI) than tricyclic (TCA) antidepressant drug therapies. We have undertaken replication studies in two independent databases. METHOD: We have examined for gender differences in SSRI and TCA antidepressant response in both retrospective and prospective naturalistic uncontrolled studies, and in subsets of melancholic and non-melancholic depressed subjects. As the US study had indicated that women under the age of 40 years were particularly likely to show a differential response to SSRIs, we examined for age, gender and interactional effects. In addition, we examined for differential SSRI and TCA responsiveness in a subset of patients who had received drugs from both classes. RESULTS: We failed to find evidence of women having a preferential response to SSRI medication or, conversely, of men having a superior response to TCA medication. Older age, however, was associated with a superior TCA response and younger age with a superior SSRI response. CONCLUSION: As few studies have examined for differential gender and age effects in response to narrow action and broad action antidepressant drugs across major depressive subtypes, gender differential effects remain to be established.

Adult↗

PubMed2003

Modern diagnostic concepts of the affective disorders.

OBJECTIVE: To review critically alternative models of depression. METHOD: Contrasting historical models are noted and some results of a study overviewing a temperament-based model for the non-melancholic disorders are presented. RESULTS: Limitations to all models are considered. CONCLUSION: As depression can present as a mood state, a syndrome, a disorder and as a disease, it is unwise to assume that a single model will suffice. A pure temperament diathesis model of non-melancholic depression is unlikely to be sufficient and would benefit from testing of additional personality constructs.

Affect↗

PubMed2003

An Australian validation study of the temperament and character inventory.

OBJECTIVE: To assess the validity of the temperament and character inventory (TCI) measure in an Australian sample. METHOD: A sample of depressed subjects completed the TCI and a measure assessing personality disorder constructs (PDCs), while family members and psychiatrists also returned PDC ratings. RESULTS: Factor analyses generally supported the TCI constructs, when the temperament and character scales were analysed separately. Self-reported PDC scores were validated against corroborative witness ratings and used to assess the TCIs concurrent validity. Validation analyses supported all TCI temperament scales, but the Self-transcendence Character scale was unassociated with PDC scores. The remaining two character scales (i.e. cooperativeness and self-directedness) were non-specifically associated with all PDC scores. CONCLUSION: Study results support the validity of the TCI scales, but question the best model for conceptualizing the TCI. It is suggested that two character scales quantify disordered functioning, while temperament scales quantify style, constructs that may be inter-related or independent in individual subjects.

Adult↗