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Biomedical subjects

L Dixon

Publications and source records attributed to L Dixon.

At least 19 recordsLinked to original sources
PubMed2002

The spectrum of DNA damage in human sperm assessed by single cell gel electrophoresis (Comet assay) and its relationship to fertilization and embryo development.

BACKGROUND: The integrity of sperm DNA is important for the success of natural or assisted fertilization, as well as normal development of the embryo, fetus and child. ICSI, by bypassing sperm selection mechanisms, increases the risk of transmitting damaged DNA and the significance of this requires investigation. METHODS: DNA damage in sperm from an unselected group of 60 men undergoing IVF treatment was measured by single cell gel electrophoresis (Comet assay) and correlated with semen and treatment cycle parameters. RESULTS: Wide spectra of sperm DNA damage were found both within and between men but no specific subgroups were identified. Semen and treatment cycle parameters were not different in men grouped according to high or low sperm DNA damage. However, regression analysis showed that DNA damage was positively associated with age (29-44 years), abnormal sperm and motility and negatively associated with sperm concentration. In ICSI cycles DNA damage was positively associated with impairment of post-fertilization embryo cleavage. CONCLUSIONS: This study contributes to the evidence of DNA damage within sperm. High loads of DNA damage measured by the Comet assay were predictive of failure of embryo development after ICSI. As it is likely that sperm with DNA damage contributed to successful fertilization and in-vitro development, potential adverse effects remain to be clarified.

Adult↗
PubMed2002

Tetracycline rapidly reaches all the constituent cells of uropathogenic Escherichia coli biofilms.

We have developed a method for visualizing Escherichia coli cells that are exposed to tetracycline in a biofilm, based on a previous report that liposomes containing the E. coli TetR(B) protein fluoresce when exposed to this antibiotic. By our method, cells devoid of TetR(B) also exhibited tetracycline-dependent fluorescence. At 50 microg of tetracycline ml(-1), planktonic cells of a uropathogenic E. coli (UPEC) strain developed maximal fluorescence after 7.5 to 10 min of exposure. A similar behavior was exhibited by cells in a 24- or 48-h UPEC biofilm, as examined by confocal laser microscopy, regardless of whether they lined empty spaces or occupied densely packed regions. Further, a comparison of phase-contrast and fluorescent images of corresponding biofilm zones showed that all the cells fluoresced. Thus, all the biofilm cells were exposed to tetracycline and there were no pockets within the biofilm where the antibiotic failed to reach. It also appeared unlikely that niches of reduced exposure to the antibiotic existed within the biofilms.

Anti-Bacterial Agents↗
PubMed2002

Chlamydia trachomatis infection and non-gonococcal urethritis in homosexual and heterosexual men in Edinburgh.

In 1998, when ligase chain reaction testing for chlamydial infection was introduced in our clinic in Edinburgh, routine clinic protocol included the testing of all heterosexual, but not homosexual, men for urethral chlamydial infection. We audited all new homosexual and bisexual male attendees with a diagnosis of chlamydial infection or non-gonococcal urethritis (NGU) in 1999, together with heterosexual men with the same diagnoses attending in alternate months of the same year. Urethral Chlamydia trachomatis infection was detected in 14.6% (350/2402) of heterosexual men and 2.4% (11/465) of homosexual men tested. Fifty percent of chlamydial infections were asymptomatic. In this population 44% (84/190) of NGU in heterosexual men is attributable to C. trachomatis as opposed to only 10% (6/59) of that in homosexual men. These rates of chlamydial infection differ from previous reports in Scotland and recent studies from the USA. Our clinic protocol has been revised to include routine testing for chlamydial infection in all men.

Ambulatory Care↗
PubMed2001

Sequence polymorphism in the human melanocortin 1 receptor gene as an indicator of the red hair phenotype.

We describe a minisequencing protocol for screening DNA samples for the presence of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which are associated with the red hair phenotype. A minisequencing profile which shows homozygosity for one of these mutations or the presence of two different mutations would strongly indicate that the sample donor is red haired. The absence of any red hair causing mutations would indicate that the sample donor does not have red hair. We report the frequencies of MC1R variants in the British red haired population.

Forensic Medicine↗
PubMed2001

Reason for medical hospitalization among adult alcohol and drug abusers.

This study attempts to identify the associations between types of substance use and particular medical problems as causes of acute hospital admission on an inpatient substance abuse consultation service. Records of all consultations performed from 1994 to 1998 were analyzed. A total of 4,526 complete records were available. Cocaine (p < .01), heroin (p < .001), and injection drug (p < .001) users were more likely to be admitted to the hospital for infection. Both alcohol (p < .001) and marijuana (p < .001) users were more likely to be hospitalized for trauma related injuries. Individuals that used alcohol were also more likely to be admitted for the treatment of gastrointestinal disorders (p < .001). Clinicians who treat patients with these diagnoses should have a high index of suspicion of co-morbid substance use disorders. Effective treatment of substance use disorders can lead to a decrease in medical morbidity, improved outcomes for individual patients, and decreased costs for the health care system.

Adult↗
PubMed2001

Differences in rates of depression in schizophrenia by race.

The purpose of this study was to determine whether demographic and clinical factors are associated with a diagnosis of depression among persons with schizophrenia and to determine the association of depression with subjective quality of life. A consecutively admitted sample of psychiatric inpatients diagnosed with schizophrenia (n = 123) were assessed for depression and quality of life. Logistic regression was used to determine factors associated with a diagnosis of depression. Multiple regression analyses were used to determine the relationship between depression and quality of life. The odds of being diagnosed with depression were seven times greater in Caucasians than in African-Americans, and three times greater in persons who were ever married. Depression was significantly associated with reduced life satisfaction in Caucasians but not African-Americans. This suggests the importance of race as a predictor of a diagnosis of depression in schizophrenia and the possibility of underdiagnosis of depression among African-Americans. The absence of the expected association between depression and quality of life in African-Americans casts doubt on the validity of the depression diagnosis using conventional diagnostic tools.

Adult↗
PubMed2001

The impact of health status on work, symptoms, and functional outcomes in severe mental illness.

This study evaluated the relationships between self-ratings of physical role functioning and general health, two components of the MOS SF-36, and a variety of demographic, quality of life, clinical, functional, and attitudinal variables in a cohort of adults living with severe and persistent mental illness (SPMI). We hypothesized that poorer self-perceptions of physical functioning and general health would be significantly related to more severe symptoms and poorer functioning and quality of life. Study subjects were 218 adults with SPMI enrolled in a randomized controlled trial comparing two vocational interventions for persons who were unemployed. Hierarchical regression analysis was used to determine whether psychiatric symptoms, poorer self-perceptions of role limitations due to physical health problems and overall general health independently contributed to more severe symptoms and poorer functioning and quality of life. Psychiatric symptoms were inversely related to size of social network and satisfaction with safety. Increased role limitations were associated with reduced medication compliance, general life satisfaction, and satisfaction with health, daily activities, and safety. Reduced general health was significantly associated with reduced work motivation, self-esteem, current inability to work, self-report of functioning, and almost all subjective life satisfaction domains. Within this group of people with severe mental illness, psychiatric symptoms were minimally associated with outcomes. Physical role limitations contributed more, and an integrated global measure of overall health perception was most important. If we are to help persons with severe mental illness maximize their quality of life and functioning, our clinical interventions should employ an approach that appreciates and recognizes the importance of the patients' experience of a holistic and integrated experience of health.

Adult↗
PubMed2001

African swine fever virus protein p54 interacts with the microtubular motor complex through direct binding to light-chain dynein.

Dynein is a minus-end-directed microtubule-associated motor protein involved in cargo transport in the cytoplasm. African swine fever virus (ASFV), a large DNA virus, hijacks the microtubule motor complex cellular transport machinery during virus infection of the cell through direct binding of virus protein p54 to the light chain of cytoplasmic dynein (LC8). Interaction of p54 and LC8 occurs both in vitro and in cells, and the two proteins colocalize at the microtubular organizing center during viral infection. p50/dynamitin, a dominant-negative inhibitor of dynein-dynactin function, impeded ASFV infection, suggesting an essential role for dynein during virus infection. A 13-amino-acid domain of p54 was sufficient for binding to LC8, an SQT motif within this domain being critical for this binding. Direct binding of a viral structural protein to LC8, a small molecule of the dynein motor complex, could constitute a molecular mechanism for microtubule-mediated virus transport.

African Swine Fever Virus↗
PubMed2001

Correlates of long-term unemployment among inner-city adults with serious and persistent mental illness.

This study identified demographic, clinical, and vocational rehabilitation-related correlates of long-term unemployment among 219 adults with severe mental illness. Fifty-one percent of the sample had been unemployed five or more years before enrollment. Older age, a diagnosis of psychosis, severity of negative symptoms, and more previous hospitalizations were all significantly related to long-term unemployment. Gender, race, education, substance disorder diagnosis, severity of negative symptoms, and vocational training experience were not. The findings underscore the relevance of clinical and neurocognitive impairments to long-term unemployment and point to the need to critically reevaluate the effectiveness of traditional vocational rehabilitation services.

Adult↗
PubMed2001

Implementing evidence-based practices for persons with severe mental illnesses.

Extensive empirical research, summarized in several reviews and codified in practice guidelines, recommendations, and algorithms, demonstrates that several pharmacological and psychosocial interventions are effective in improving the lives of persons with severe mental illnesses. Yet the practices validated by research are not widely offered in routine mental health practice settings. As part of an effort to promote the implementation of evidence-based practice, the authors summarize perspectives on how best to change and sustain effective practice from the research literature and from the experiences of administrators, clinicians, family advocates, and services researchers. They describe an implementation plan for evidence-based practices based on the use of toolkits to promote the consistent delivery of such practices. The toolkits will include integrated written material, Web-based resources, training experiences, and consultation opportunities. Special materials will address the concerns of mental health authorities (funders), administrators of provider organizations, clinicians, and consumers and their families.

Community Mental Health Services↗
PubMed2001

Implementing evidence-based practices in routine mental health service settings.

The authors describe the rationale for implementing evidence-based practices in routine mental health service settings. Evidence-based practices are interventions for which there is scientific evidence consistently showing that they improve client outcomes. Despite extensive evidence and agreement on effective mental health practices for persons with severe mental illness, research shows that routine mental health programs do not provide evidence-based practices to the great majority of their clients with these illnesses. The authors define the differences between evidence-based practices and related concepts, such as guidelines and algorithms. They discuss common concerns about the use of evidence-based practices, such as whether ethical values have a role in shaping such practices and how to deal with clinical situations for which no scientific evidence exists.

Combined Modality Therapy↗
PubMed2001

Use and costs of ambulatory care services among Medicare enrollees with schizophrenia.

OBJECTIVE: The objective of this study was to identify predictors of the use and cost of ambulatory care services among Medicare recipients with schizophrenia. METHODS: The design was a cross-sectional analysis of Medicare claims in 1991. The study subjects were a 5 percent random sample of all persons in the United States who had at least one Medicare service claim in 1991 and who were diagnosed as having schizophrenia in any care setting. Outcome measures included use and cost of any ambulatory care service, individual therapy, psychiatric somatotherapy, group therapy, or family therapy. RESULTS: For nearly 25 percent of the total sample of 12,440, no claims were filed for ambulatory care services in 1991. The mean+/-SD number of ambulatory care visits during the year was 7.9+/-21. The most frequently used type of therapy was individual therapy (5+/-14 visits). The mean+/-SD yearly cost of care for persons who received ambulatory care services was $470+/-$1,028. Among persons under 65 years of age, Caucasians were about 1.5 times as likely as African Americans to have received an ambulatory care service and 1.3 times as likely to have received individual therapy. Persons who were 65 or older were less likely to have received any service. Among service recipients, costs of care were lower for African Americans and for older people. CONCLUSIONS: The use of Medicare-funded ambulatory care services by persons with schizophrenia varied by race and age. Further investigation is required to determine whether subgroups of individuals who do not have additional insurance coverage or access to services are receiving substandard care.

Aged↗
PubMed2001

Evidence-based practices for services to families of people with psychiatric disabilities.

Family psychoeducation is an evidence-based practice that has been shown to reduce relapse rates and facilitate recovery of persons who have mental illness. A core set of characteristics of effective family psychoeducation programs has been developed, including the provision of emotional support, education, resources during periods of crisis, and problem-solving skills. Unfortunately, the use of family psychoeducation in routine practice has been limited. Barriers at the level of the consumer and his or her family members, the clinician and the administrator, and the mental health authority reflect the existence of attitudinal, knowledge-based, practical, and systemic obstacles to implementation. Family psychoeducation dissemination efforts that have been successful to date have built consensus at all levels, including among consumers and their family members; have provided ample training, technical assistance, and supervision to clinical staff; and have maintained a long-term perspective.

Evidence-Based Medicine↗
PubMed2001

Predictors of dissemination of family psychoeducation in community mental health centers in Maine and Illinois.

OBJECTIVE: The aim of this study was to determine whether it is possible at the time of staff training to predict whether a mental health center will succeed in implementing family psychoeducation services. METHODS: Fifteen mental health agencies in Maine and 51 in Illinois in which clinicians and administrators were trained in multifamily psychoeducation were studied. Participants were surveyed immediately after their initial training sessions and nine months later. Participants' demographic characteristics, agency characteristics, and principal components derived from the survey data were analyzed to identify factors associated with implementation of family psychoeducation services. RESULTS: The regression model successfully predicted which sites would succeed. Success was more likely at sites where the treatment model was viewed more positively at the outset, where real and perceived resource limitations were addressed, where inducements to implementation were seen as less important, and where attention was paid to the difference between new and existing treatment methods. Nearly all the Maine sites (14, or 93 percent) implemented multifamily psychoeducation services, whereas only five of the Illinois sites (10 percent) implemented this form of treatment. The Maine trainees were less skeptical about family psychoeducation and more interested in receiving supervision and consultation. In Maine there was wide-ranging and local consensus before and during implementation, and more federal funding was available than in Illinois. CONCLUSIONS: Surveys of clinicians allowed prediction of which sites would successfully implement family psychoeducation services. Consensus building and funding appeared to be critical to successful outcomes.

Adult↗
PubMed2001

Pilot study of the effectiveness of the family-to-family education program.

This study assessed the efficacy of the Family-to-Family Education Program, a structured 12-week program developed by the National Alliance for the Mentally Ill. A total of 37 family members who participated in the program were evaluated by an independent research team of trained family member assessors at baseline, after completing the program, and six months after program completion. After completing the program, the participants demonstrated significantly greater family, community, and service system empowerment and reduced displeasure and worry about the family member who had a mental illness. These benefits were sustained at six months.

Adult↗
PubMed2001

Variables associated with disparities in treatment of patients with schizophrenia and comorbid mood and anxiety disorders.

OBJECTIVE: The study compared self-reported comorbid affective and anxiety disorder diagnoses and treatments of African-American and Caucasian subjects in a large sample of patients who had a diagnosis of schizophrenia. METHODS: A total of 685 patients receiving treatment for schizophrenia were interviewed as part of the Schizophrenia Patient Outcomes Research Team study. The associations of race with past and current diagnoses and with current treatment for depression, mania, and anxiety disorders were assessed with multivariate analyses. RESULTS: African Americans were significantly less likely than Caucasians to report having a past or current diagnosis of depression, manic-depression, or anxiety disorder and to be receiving current treatment for these disorders. Gender, education, and marital status were also associated with presence of a comorbid diagnosis and receipt of treatment. CONCLUSIONS: The study suggests the possibility of racial and other disparities in the diagnosis and treatment of patients with schizophrenia and comorbid affective and anxiety disorders. Although various causal explanations are plausible, all point toward the need for enhanced cross-cultural competence at all levels of mental health care, especially in the diagnosis and treatment of comorbid psychiatric illnesses.

Adult↗
PubMed2001

Urinary diversions: a review of nursing care.

The nurse plays an important part in the preoperative and postoperative management of the patient with a urinary diversion. Although urinary diversion as a surgical alternative has been performed since the mid 1800s, improvements in technique and management over the past 10 years warrant discussion. Three types of urinary diversion procedures are discussed along with suggestions for optimal nursing management during the postoperative period.

Humans↗