Biomedical subjects

R Purcell

Publications and source records attributed to R Purcell.

At least 19 recordsLinked to original sources

PubMed2003

Prognostic importance of survivin in breast cancer.

Survivin is a member of the inhibitor of apoptosis (IAP) family, and is also involved in the regulation of cell division. Survivin is widely expressed in foetal tissues and in human cancers, but generally not in normal adult tissue. This study examined the expression of surviving protein in a series of 293 cases of invasive primary breast carcinoma. Survivin immunoreactivity was assessed using two different polyclonal antibodies, and evaluated semiquantitatively according to the percentage of cells demonstrating distinct nuclear and/or diffuse cytoplasmic staining. Overall, 60% of tumours were positive for survivin: 31% demonstrated nuclear staining only, 13% cytoplasmic only, and 16% of tumour cells demonstrated both nuclear and cytoplasmic staining. Statistical analysis revealed that survivin expression was independent of patient's age, tumour size, histological grade, nodal status, and oestrogen receptor status. In multivariate analysis, nuclear survivin expression was a significant independent prognostic indicator of favourable outcome both in relapse-free and overall survival (P<0.001 and P=0.01, respectively). In conclusion, our results show that survivin is frequently overexpressed in primary breast cancer. Nuclear expression is most common and is an independent prognostic indicator of good prognosis.

Adult↗

PubMed2001

Comparative genomics of Listeria species.

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Adaptation, Physiological↗

PubMed2001

Stalking: new constructions of human behaviour.

OBJECTIVE: In the last decade stalking has emerged as a significant social problem, which now constitutes a specific form of criminal offence in most English-speaking nations. This paper examines why stalking has become a major social problem and why it should be of particular concern to mental health professionals. METHOD: Using the extant literature, the history of the emergence of stalking as social, legal and behavioural science discourses is presented. An attempt is made to understand the social and cultural forces which shaped our current understanding of the phenomenon of stalking. RESULTS: Stalking flourishes in a variety of contexts; the social conditions conducive to such behaviour include greater instability in intimate relationships, a culture of blame and entitlement and a growing social anxiety that emphasizes vulnerability to crime and suspicion regarding the intentions of strangers. Stalking is now an established category whose utility is in directing social, legal and health energies to support victims and relieve stalkers of their burden of pursuit. CONCLUSIONS: Stalking is a curious construction born of a range of tensions in contemporary culture but has proved to be a useful label and a useful concept. In part due to the emergence of the concept of stalking, laws are now available to protect, and services increasingly geared to support, the victims of persistent harassment.

Female↗

PubMed2001

A study of women who stalk.

OBJECTIVE: The authors examined whether female stalkers differ from their male counterparts in psychopathology, motivation, behavior, and propensity for violence. METHOD: Female (N=40) and male (N=150) stalkers referred to a forensic mental health clinic were compared. RESULTS: In this cohort, female stalkers were outnumbered by male stalkers by approximately four to one. The demographic characteristics of the groups did not differ, although more male stalkers reported a history of criminal offenses. Higher rates of substance abuse were also noted among the male stalkers, but the psychiatric status of the groups did not otherwise differ. The duration of stalking and the frequency of associated violence were equivalent between groups. The nature of the prior relationship with the victim differed, with female stalkers more likely to target professional contacts and less likely to harass strangers. Female stalkers were also more likely than male stalkers to pursue victims of the same gender. The majority of female stalkers were motivated by the desire to establish intimacy with their victim, whereas men showed a broader range of motivations. CONCLUSIONS: Female and male stalkers vary according to the motivation for their pursuit and their choice of victim. A female stalker typically seeks to attain a close intimacy with her victim, who usually is someone previously known and frequently is a person cast in the professional role of helper. While the contexts for stalking may differ by gender, the intrusiveness of the behaviors and potential for harm does not.

Adolescent↗

PubMed2000

Same-gender stalking.

Although stalkers most commonly target victims of the opposite gender, the results of larger and less selective studies suggest that same-gender stalking occurs with greater frequency than formerly thought. This study reviews the exiguous literature on same-gender stalking and presents the findings from a clinical study of 29 same-gender stalking cases that were referred to a forensic psychiatry center. The demographic characteristics, behavior, motivations, and psychopathology of same-gender stalkers are compared with a sample of 134 opposite-gender stalkers. The two groups were similar in many respects, with some discrepancies evident in the prior relationship between victim and stalker, harassment methods, and stalking motives. The impact of same-gender stalking on its victims is examined, and the implications of these findings are discussed.

Adolescent↗

PubMed1999

Viral clearance without destruction of infected cells during acute HBV infection.

Viral clearance during hepatitis B virus (HBV) infection has been thought to reflect the destruction of infected hepatocytes by CD8(+) T lymphocytes. However, in this study, HBV DNA was shown to largely disappear from the liver and the blood of acutely infected chimpanzees long before the peak of T cell infiltration and most of the liver disease. These results demonstrate that noncytopathic antiviral mechanisms contribute to viral clearance during acute viral hepatitis by purging HBV replicative intermediates from the cytoplasm and covalently closed circular viral DNA from the nucleus of infected cells.

Acute Disease↗

PubMed1999

Tourette's and comorbid syndromes: obsessive compulsive and attention deficit hyperactivity disorder. A common etiology?

Tourette's syndrome (TS), a neuropsychiatric movement disorder that manifests itself in childhood, is often associated with comorbid symptomatology, such as obsessions, compulsions, hyperactivity, distractibility, and impulsivity. Epidemiological studies suggest that a substantial number of TS patients develop clinical levels of obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD). This review aims to provide an integrated account of the three disorders in terms of their comorbidity. Neuroimaging studies suggest that all three disorders involve neuropathology of the basal-ganglia thalamocortical (BGTC) pathways: TS in the sensorimotor and limbic BGTC circuits; OCD in the prefrontal and limbic BGTC pathways; and ADHD in the sensorimotor, orbitofrontal, and limbic BGTC circuits. The pattern of comorbidity and other evidence indicates that the TS gene(s) may be responsible for a spectrum of disorders, including OCD and ADHD, but also that the disorders OCD and ADHD can exist in their own right with their own etiologies.

Attention Deficit Disorder with Hyperactivity↗

PubMed1999

Impairment of olfactory identification in obsessive-compulsive disorder.

BACKGROUND: Olfactory identification ability has been associated with processing in the orbitofrontal cortex (OFC), an area that has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD). Although olfactory sensitivity is normal in patients with OCD, no study has investigated olfactory identification in this disorder. METHODS: A group of 20 subjects with OCD and 23 age- and education-matched controls performed a standardized test of olfactory identification. They also performed computerized tests of spatial memory span, spatial working memory and spatial recognition memory that have been shown previously to be sensitive to cognitive deficits in patients with OCD. RESULTS: Performance on the olfactory identification task, spatial recognition task and spatial span task was significantly worse in the OCD group than controls. CONCLUSIONS: While impairment in spatial cognition is consistent with previous studies of OCD, its significance for brain-behaviour models of OCD is unclear. However, the finding of abnormal olfactory identification in patients with OCD is consistent with the hypothesis that there is a disruption to processing at the level of the OFC in the disorder.

Adult↗

PubMed1999

Abnormalities of internally generated saccades in obsessive-compulsive disorder.

BACKGROUND: We aimed to utilize tests of saccadic function to investigate whether cognitive abnormalities in obsessive-compulsive disorder (OCD) arise from a dysfunction of inhibitory processes or whether they reflect a more general difficulty in guiding behaviour on the basis of an internal representation of task goal. METHODS: Twelve patients with OCD and 12 matched controls performed a visually-guided saccade task, a volitional prosaccade task and an antisaccade task. The latency and gain of saccades was compared between groups for the three saccade tasks. The number of antisaccade errors was also calculated and compared between groups. RESULTS: There was no difference for antisaccade error rates between the groups. The latency of visually guided saccades did not differ between groups, however the latency of both volitional prosaccades and antisaccades was significantly slower in the patients with OCD than in controls. The difference in latency between volitional prosacades and antisaccades, however, was equal between groups. CONCLUSIONS: These results suggest that patients with OCD have an abnormality in guiding behaviour on the basis of an internal representation of the task goal, rather than a problem with inhibiting reflexive behaviour.

Adult↗

PubMed1999

Study of stalkers.

OBJECTIVE: This clinical study ws devised to elucidate the behaviors, motivations, and psychopathology of stalkers. METHOD: It concerned 145 stalkers referred to a forensic psychiatry center for treatment. RESULTS: Most of the stalkers were men (79%, N = 114), and many were unemployed (39%, N = 56); 52% (N = 75) had never had an intimate relationship. Victims included ex-partners (30%, N = 44), professional (23%, N = 34) or work (11%, N = 16) contacts, and strangers (14%, N = 20). Five types of stalkers were recognized: rejected, intimacy seeking, incompetent, resentful, and predatory. Delusional disorders were common (30%, N = 43), particularly among intimacy-seeking stalkers, although those with personality disorders predominated among rejected stalkers. The duration of stalking was from 4 weeks to 20 years (mean = 12 months), longer for rejected and intimacy-seeking stalkers. Sixty-three percent of the stalkers (N = 84) made threats, and 36% (N = 52) were assaultive. Threats and property damage were more frequent with resentful stalkers, but rejected and predatory stalkers committed more assaults. Committing assault was also predicted by previous convictions, substance-related disorders, and previous threats. CONCLUSIONS: Stalkers have a range of motivations, from reasserting power over a partner who rejected them to the quest for a loving relationship. Most stalkers are lonely and socially incompetent, but all have the capacity to frighten and distress their victims. Bringing stalking to an end requires a mixture of appropriate legal sanctions and therapeutic interventions.

Adolescent↗

PubMed1999

Stalking: false claims of victimisation.

BACKGROUND: False allegations of victimisation although uncommon are important to recognise. This paper examines those who falsely claim to have been the victims of stalking. AIMS: To highlight the phenomenon of false victims of stalking. METHOD: Twelve individuals who falsely claimed to be victims of stalking were compared with a group of 100 true stalking victims. RESULTS: False stalking victims presented for help earlier than real victims and were less likely to claim harassment via letters. They reported equivalent levels of violence directed at themselves but seldom claimed others were attacked. Five types of false claimants were recognisable. False victims consumed more medical services than genuine stalking victims and they were more likely to be embroiled in legal action. They reported similar levels of distress with suicidal ruminations in over 40%. CONCLUSIONS: The current interest in stalking is promoting false claims of being stalked. Early identification of these cases and appropriate intervention are essential to both minimising abuses of resources available to true victims and equally to ensure appropriate care for those who express their own disordered state in false claims of victimisation.

Adult↗

PubMed1998

Human class I supertypes and CTL repertoires extend to chimpanzees.

Using an in vitro peptide stimulation strategy, two chimpanzees that were acutely infected by the hepatitis B virus (HBV) produced peripheral blood CTL responses to several HBV-encoded epitopes that are known to be recognized by class I-restricted CTL in acutely infected humans. One animal responded to three HBV peptides that, in humans, are restricted by HLA-A2; the other animal responded to three peptides that are restricted by HLA-B35 and HLA-B51, members of the HLA-B7 supertype in man. The peptides recognized by each chimp corresponded with the ability of its class I molecules to bind peptides containing the HLA-A2 and HLA-B7 supermotifs. Similar, apparently class I-restricted CTL responses to some of these peptides were also detected in occasional HBV-uninfected chimps. These results demonstrate that the CTL repertoire overlaps in humans and chimps and that the HLA-A2 and HLA-B7 supertypes extend to the chimpanzee. Based on these results, the immunogenicity and efficacy of vaccines designed to induce CTL responses to human HLA-restricted viral epitopes may be testable in chimpanzees.

Amino Acid Sequence↗

PubMed1998

Cognitive deficits in obsessive-compulsive disorder on tests of frontal-striatal function.

BACKGROUND: Although neuropsychological and neuroimaging studies of obsessive-compulsive disorder (OCD) have implicated the frontal cortex and subcortical structures in the pathophysiology of the disorder, few studies have examined cognitive function in patients with OCD on tasks validated in the assessment of frontal lobe and subcortical dysfunction. METHODS: The accuracy and latency of executive and visual memory function was assessed in 23 nondepressed OCD patients and 23 normal healthy controls matched for age, sex, education, and estimated IQ. RESULTS: The patients with OCD performed within the normal range on tasks of short-term memory capacity, delay dependent visual memory, pattern recognition, attentional shifting, and planning ability; however, specific cognitive deficits related to spatial working memory, spatial recognition, and motor initiation and execution were observed in the patient group. These deficits were not correlated with aspects of the patients' intellectual functioning or comorbid psychological symptoms, suggesting that the impairments were related to the specific clinical features of OCD. CONCLUSIONS: Patients with OCD showed specific cognitive deficits on tasks of executive and visual memory function. The pattern of impaired performance in these patients was qualitatively similar to the performance of patients with frontal lobe excisions and subcortical pathology on the same test battery, suggesting that the underlying pathophysiology of the disorder could best be conceptualized as reflecting dysfunction of frontal-striatal systems.

Adult↗

PubMed1998

Neuropsychological deficits in obsessive-compulsive disorder: a comparison with unipolar depression, panic disorder, and normal controls.

BACKGROUND: The neuropsychological dysfunction associated with obsessive-compulsive disorder (OCD) has similarities to the deficits reported in other affective or anxiety disorders. We directly compared cognitive function in patients with OCD with that in matched patients with unipolar depression and panic disorder and healthy control subjects to establish the specific nature of neuropsychological deficits in OCD. METHODS: Thirty patients with OCD, 30 patients with panic disorder, 20 patients with unipolar depression, and 30 controls completed a computerized neuropsychological battery that assessed the accuracy and latency of executive, visual memory, and attentional functions. RESULTS: The groups did not differ according to age, years of education, or estimated IQ. However, we found group differences in cognitive performance. The patients with OCD were impaired on measures of spatial working memory, spatial recognition, and motor initiation and execution. In contrast, performance of these tasks by patients with panic disorder or depression did not differ from that of controls. There were no group differences for performance on the measures of planning, cognitive speed, pattern recognition, and delayed matching to sample, although patients with depression were impaired for attentional set shifting. CONCLUSIONS: Neuropsychological deficits were observed in patients with OCD that were not observed in matched patients with panic disorder or unipolar depression. As such, the cognitive dysfunction in OCD appears to be related to the specific illness processes associated with the disorder.

Adult↗

PubMed1997

The hepatitis C virus: overview.

Our knowledge of hepatitis C virus (HCV) dates only from 1975, when non-A, non-B hepatitis was first recognized. It was not until 1989 that the genome of the virus was first cloned and sequenced, and expressed viral antigens used to develop serological assays for screening and diagnosis. HCV is in a separate genus of the virus family Flaviviridae. It is a spherical enveloped virus of approximately 50 nm in diameter. Its genome is a single-stranded linear RNA molecule of positive sense and consists of a 5' noncoding region, a single large open reading frame, and a 3' noncoding region. The open reading frame encodes at least three structural and six nonstructural proteins. The genome is characterized by significant genetic heterogeneity, based on which HCV isolates can be classified into six major genotypes and more than 50 subtypes. Even individual isolates of HCV are genetically heterogeneous (quasispecies diversity). Genetic heterogeneity of HCV is greatest in the amino-terminal end of the second envelope protein (hypervariable region 1). This region may represent a neutralization epitope that is under selective pressure from the host's humoral immune response. Infection with HCV proceeds to chronicity in more than 80% of cases, and even recovery does not protect against subsequent re-exposure to the virus. The development of a broadly protective vaccine against HCV will therefore require a better understanding of the molecular biology and immune response to this virus.

Animals↗

PubMed1997

Powered functional endoscopic sinus surgery.

The use of powered instrumentation in functional endoscopic sinus surgery has been a revolutionary development in the surgical treatment of chronic sinusitis. Several studies have demonstrated the safety, efficacy, and ease of use of this new technique. To provide support and coordinate the surgical process in powered functional endoscopic sinus surgery procedures, perioperative nurses must have an appreciation for its specific equipment handling and for appropriate patient care. This article describes a specific protocol that perioperative nurses can use to facilitate efficient and safe surgical environments for patients who undergo powered endoscopic sinus surgery procedures.

Chronic Disease↗

PubMed1997

Neuropsychological function in young patients with unipolar major depression.

BACKGROUND: While neuropsychological studies have consistently reported impaired cognition in elderly patients with unipolar depression, studies of cognitive function in younger patients with depression have produced equivocal results. The aim of this study was to examine the presence and nature of cognitive deficits in young patients with depression. METHODS: Neuropsychological function was assessed in 20 young patients with unipolar depression, in comparison to 20 age-, education- and IQ- matched controls. Subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were employed, as this battery has proved sensitive to deficits in middle-aged and elderly patients with depression. RESULTS: The patients were not impaired for short-term memory capacity, spatial working memory, planning ability, cognitive speed, delayed matching to sample or recognition memory. Compared to controls, the patients showed impaired subsequent movement latencies on the Tower of London task, suggesting deficits in the ability to sustain motor responses in depression. The depression group were also impaired on the task of attentional set shifting, requiring more trials to criterion at the intradimensional stage of the task and being more likely to fail the task at the extradimensional shift stage than controls. Further analysis indicated that half of the depression group failed to complete all stages of the set shifting task. These patients were more likely to have required in-patient hospitalization at some time during their illness. CONCLUSIONS: These results indicate that there are specific cognitive deficits in young patients with depression and that their presence may be related to a history of hospitalization.

Adolescent↗

PubMed1995

Acute viral hepatitis in Saudi Arabia: seroepidemiological analysis, risk factors, clinical manifestations, and evidence for a sixth hepatitis agent.

We conducted a prospective, descriptive cohort study of all 217 cases of acute viral hepatitis (AVH) seen in adults during 1992 at the sole hospitals with infectious disease departments in the second and third largest cities in the Kingdom of Saudi Arabia. In addition, we undertook a nested case-control study. Our goals were (1) to determine the causes, demographics, risk factors, and clinical characteristics of AVH in the Kingdom; (2) to evaluate the reliability of diagnostic tests for acute hepatitis C and E; and (3) to assess the relative importance, characteristics, and risk factors of a sixth hepatitis agent, non-A-E. All cases and controls completed a questionnaire. Cases provided blood samples for studies of serum bilirubin, alanine and aspartate aminotransferases, and antibody to hepatitis viruses as well as genome detection studies. The results of serological and molecular tests were used to categorize each case as hepatitis A, B, C, D, E, or non-A-E. Historical, clinical, and laboratory determinants were statistically analyzed by comparisons between groups with different types of AVH and controls. Analysis of risk factors suggested that hepatitis C and D were parenterally transmitted, while hepatitis A, E, and non-A-E were not; the route of transmission of hepatitis B was unclear. Hepatitis E was strongly associated with living or traveling on the Indian subcontinent. The clinical disease caused by all six agents was indistinguishable. The putative sixth agent caused 13% of cases. The second-generation tests for antibody to HCV and HEV were relatively reliable for the diagnosis of AVH.

Acute Disease↗