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Biomedical subjects

N Dunbar

Publications and source records attributed to N Dunbar.

At least 19 recordsLinked to original sources
PubMed2001

The effects of knowledge, attitudes, and significant others on decisions to enroll in a clinical trial on osteoporosis: implications for recruitment of older African-American women.

This preliminary study explored the roles of knowledge, attitudes, and significant others on decisions of older African-American women to enroll in a clinical trial involving estrogen and osteoporosis. Sixteen older African-American women (average age 75 years) participated in three focus groups. Twelve of the women had enrolled in the clinical trial and four, although eligible, refused to enroll. Discussions revealed that knowledge of osteoporosis and estrogen and expectations of personal rewards and group benefits from medical research appear to differentiate the women who participated in the clinical trial from those who refused. The women who participated also perceived the research institution as accessible. In addition, assuring full disclosure of testing procedures and test results eased their apprehensions about participation. However, the women who refused to enroll saw no personal benefit and were unwilling to expose themselves, in part because of their age, to the risks of taking estrogen and the uncertain outcomes of the clinical trial. The study illustrates how focus groups can be used to develop multiple strategies to enable recruitment of older African-American women with different demographic characteristics, levels of knowledge, and attitudes toward a disease and medical research.

Black or African American↗
PubMed1997

The health of a group of young Australians in a New South Wales juvenile justice detention centre: a pilot study.

OBJECTIVE: To consider the health profile of a sample of young, largely male Australians as assessed on their admission to a New South Wales Juvenile Justice Detention Centre. METHOD: A retrospective analysis of primary care nurse health records for 100 sequential admissions. RESULTS: Of the 97 males and three females (mean age = 15.9 years), 30 were Aboriginal and 39 did not live with either parent at the time of admission. Respiratory illness, such as bronchitis and asthma were common. These diagnoses were overshadowed by histories of significant physical injury. The sample was at high risk of sexually transmitted disease. Forty-six per cent had prior contact with a mental health professional, 26% reported they had thought of suicide and 9% reported having attempted suicide. There was a high prevalence of substance abuse. CONCLUSION: The health of these young Australians is at risk from every perspective. Improving the quality of their health assessments is an important issue for the clinicians who attend them as individuals and for policy makers who aim to reduce the considerable social and economic cost of juvenile crime. The discussion of these results from one centre has revealed opportunities to make such improvements. There is a need for a gathering of expertise to address the issue, preferably on a national basis.

Adolescent↗
PubMed1997

Neuropsychological Dysfunction in HIV Infection:A Review.

FIfty-six studies which used neuropsychological tests to investigate areas of function affected by central nervous system dysfunction in HIV were reviewed. Only studies which compared the performance of HIV + subjects to HIV - controls using analysis of variance techniques were included. The results are examined in terms of broad neuropsychological function domains, and are examined separately for asymptomatic and symptomatic subjects. Studies which did and did not find significant differences between HIV + and HIV - subjects were compared in terms of various confounding factors such as risk groups, number of tests, sample size and subject characteristics. There was evidence for some dysfunction among subjects who are otherwise asymptomatic in the areas of verbal memory (27% of studies), executive function (43%), motor performance (20%) and information processing (44%). Studies of subjects with more advanced HIV infection showed consistent evidence of abnormal functioning in the areas of verbal (48% of studies) and visual memory (43%), executive functioning (71%), complex attention (62%), motor performance (37%) and information processing (69%). These deficits occurred prior to the onset of clinically apparent dementia. There were no consistent significant differences between studies which did and did not find significant differences between HIV + and HIV - subjects in terms of most of the confounding variables investigated, although studies of ASX subjects were more likely to find differences between HIV + subjects and controls with larger neuropsychological test battereies. However, much of the variation in results due to the neuropsychological tests used. In many cases, tests which relied on functions with a frontal lobe component were more likely to find significant results.

Attention↗
PubMed1996

Predictive markers of AIDS dementia complex: CD4 cell count and cerebrospinal fluid concentrations of beta 2-microglobulin and neopterin.

A predictive marker for AIDS dementia complex (ADC) in a cohort of neurologically asymptomatic human immunodeficiency virus type 1 (HIV-1)-infected patients with < 200 CD4 cells/microL was sought. Patients were assessed neurologically and neuropsychologically at entry. Blood and cerebrospinal fluid (CSF) were taken for assay of beta 2-microglobulin (beta 2M), and neopterin and T cell subsets were assessed from blood. Patients were evaluated every 4 months. Of 37 patients recruited, 35 had sufficient follow-up data. Seventeen patients progressed to ADC stage > or = 1. In univariate analyses, concentrations of CSF beta 2M and neopterin and CD4 cell count were each significantly associated with ADC development. In a multivariate analysis, concentrations of CSF beta 2M remained significant, with levels > 5 mg/L carrying approximately 17 times the risk of ADC. CSF beta 2M and neopterin levels and CD4 cell count are useful in identifying patients at risk of ADC and as such can be used to target high-risk patients so therapy can be optimized.

AIDS Dementia Complex↗
PubMed1996

Pilot study of the efficacy of atevirdine in the treatment of AIDS dementia complex.

OBJECTIVES: To determine the efficacy of the non-nucleoside reverse transcriptase inhibitor atevirdine in the treatment of AIDS dementia complex (ADC). DESIGN: Open label pilot study. METHODS: Ten patients with ADC (stage 1 or 2) who were intolerant to zidovudine or dideoxyinosine, or in whom the antiretrovirals had failed to prevent further decline in CD4 cell levels, were entered into the study. Atevirdine, 1800 mg daily in three divided doses, was given over a 12-week period. Patients were assessed neurologically and neuropsychologically every 4 weeks. Cerebrospinal fluid analysis was performed at entry and at weeks 4 and 12. Technetium-99 exametazine single photon emission computed tomographic cerebral perfusion scans and magnetic resonance imaging brain scans were performed at weeks 0 and 12. RESULTS: Five patients completed the 12 week protocol. Four of these five responded to atevirdine, as judged by quantified neurological and neuropsychological assessments. Atevirdine was well tolerated apart from the development of rash, anxiety, intermittent diarrhoea and fatigue. CONCLUSIONS: These preliminary results suggest that atevirdine is efficacious in the treatment of ADC. Larger blinded studies of this class of drug in the treatment of ADC are required.

AIDS Dementia Complex↗
PubMed1996

Clinical Markers of the Presence of Dementia and Neuropsychological Impairment in HIV Infection.

OBJECTIVE: To identify clinical, laboratory and demographic markers which are associated with the presence of dementia and neuropsychological impairment in severely immunodeficient patients. METHOD: Fifty-nine HIV+ patients participated in the study. Patients were assessed neurologically and neuropsychologically, and a subset of patients underwent lumbar punctures. Logistic regression was used to determine which variables from a set including age, education, IQ, depression, anxiety, CD4 cell counts, haemoglobin, serum and CSF â2 microglobulin and neopterin, constitutional symptoms, past opportunistic infections and use of antiretroviral therapy was associated with the occurrence of dementia and neuropsychological impairment. RESULTS: An increased likelihood of neurological and neuropsychological dysfunction was associated with diarrhoea at some time in the recent past, elevated serum neopterin at the time of assessment, and increased age. A decreased likelihood of impairment was associated with a higher estimated IQ, more years of education, and the presence of an AIDS-defining illness at the time of assessment. CONCLUSION: Recent diarrhoea, elevated serum neopterin, advanced age and low education and IQ can serve as ''signals'' for the presence of neurological and neuropsychological dysfunction.

AIDS Dementia Complex↗
PubMed1994

The transmandibular implant: from progressive bone loss to controlled bone growth.

PURPOSE: In a prospective study, 146 consecutive transmandibular implant (TMI) patients were treated according to revised surgical and prosthetic protocols to induce and control bone growth. Revisions included 1) placement of transosseous posts and cortical screws between the mental foramina so that two threads extended beyond the alveolar crest of the mandible without protruding through the mucosa and 2) fabrication of an implant-borne prosthesis that rested on the retromolar pads with a gap of 2 mm between the denture base and the mucosal tissues in the saddle areas. PATIENTS AND METHODS: Measurements of the height of the mandible were made using a digital millimeter calliper and panoramic radiographs, with the enlargement calculated for each radiograph. The follow-up period ranged from 18 to 51 months. RESULTS: Bone growth was present in 131 of the 146 patients whereas the bone resorption was arrested in the remaining patients. Increase in bony apposition varied from 9 mm in patients with severe mandibular atrophy to 2 mm in patients with mild atrophy. CONCLUSION: The revised surgical and prosthetic protocols for TMI insertion and rehabilitation are advocated to prevent further alveolar resorption and to promote bone growth in patients with mandibular atrophy.

Adult↗
PubMed1994

Neuropsychological function in asymptomatic HIV-1 infection: methodological issues.

There have been conflicting reports as to whether significant neuropsychological deterioration occurs in asymptomatic HIV-1 infection. Comparisons among studies have been hindered by substantial variations in sample size, statistical methods, definitions of neuropsychological abnormality, and attention to potential confounding factors. In this study, the neuropsychological performance of 44 subjects with asymptomatic HIV-1 infection and 41 seronegative (SN) controls was compared using analysis of variance models. Rates of abnormality were also determined using commonly employed impairment criteria. The seropositive (SP) subjects performed comparably to SN controls once differences in full scale IQ were taken into account. Rates of abnormality for HIV-1 SP subjects were estimated at 10%, 17.5%, and 67.5% by three different criteria, and were not significantly different from the rates of the control group. The findings indicated that both premorbid characteristics, and the validity and biases of definitions of impairment should be examined and incorporated into the interpretation of study findings.

Adult↗
PubMed1992

Changes in neuropsychological performance of AIDS-related complex patients who progress to AIDS.

OBJECTIVE: To investigate the changes in neuropsychological performance associated with progression from AIDS-related complex (ARC) to AIDS. DESIGN: A repeated measures design was used to compare three groups: ARC patients who progressed to AIDS (n = 15), those who did not (n = 19) and seronegative controls (n = 16). METHODS: The three groups were compared on tests of memory, information processing, motor performance, attention and conceptual flexibility. Clinical and immunological characteristics were recorded. Rates of neuropsychological impairment among the three groups were calculated and compared. RESULTS: The only significant difference between the groups at baseline was for one measure of motor performance. Repeated measures analysis indicated that there was a differential rate of change for the three subject groups for tasks of motor performance and attention. ARC patients who progressed to AIDS did not differ significantly from the non-progressors, although both groups showed significant deterioration over time compared with seronegative controls. Although there was a tendency for the progressors to have a higher rate of impairment, there were no consistent significant differences between visits. CONCLUSION: There were no significant changes in performance exclusively associated with progression to AIDS.

AIDS-Related Complex↗
PubMed1992

Anxiety, depression and HIV related symptomatology across the spectrum of HIV disease.

Levels of anxiety and depression were assessed for 207 HIV seropositive homosexual/bisexual men (AIDS = 34, ARC = 72, asymptomatic HIV infection = 101), and 36 seronegative controls. Lymphocyte subset enumeration, history of opportunistic infections, and occurrence of HIV-related symptoms were recorded at the time of assessment. No differences between groups were found on age, educational level, state/trait anxiety or depression scores. Neither the number of symptoms reported, their duration, severity, frequency of occurrence, nor the proportion of patients who reported a specific symptom was different between the three HIV seropositive groups. Severity of anxiety and depression was related to the magnitude of symptomatology, but not associated with either degree of immunodeficiency, number of opportunistic infections or diagnostic group. Principal component analysis extracted five symptom factors (cognitive, affective, psychosocial, neurological and physical), none of which predicted state anxiety scores. However, affective and psychosocial symptom factors predicted trait anxiety and depression scores. The results indicate that ratings of anxiety and depression are independent of stage of HIV infection, may be in part mediated by constitutional and physical symptoms of HIV disease, but are primarily associated with the presence of psychological and psychosocial symptoms.

AIDS Dementia Complex↗
PubMed1976

Effect of C. Parvum on immunization with irradiated tumour cells.

S.c. injection of tumour cells or small pieces of tumour irradiated to a dose of 22,000 rad evoked resistance to live challenge with the same tumour (a CBA strain fibrosarcoma induced with methylcholanthrene) 14 days later. This resistance was, however, over-ridden if the challenging inoculum was sufficiently large, and did not develop if the cells were irradiated to 100,000 rad. The resistance evoked by injection of 10(6) irradiated tumour cells was impaired by i.p. injection of 1-4 mg C. parvum 5 days before, and virtually abolished by a similar injection 11 days after, the irradiated cells. The effect of s.c. injection of a mixture of 10(6) irradiated cells and C. parvum 14 days before live challenge depended on the dose of C. parvum. With 0-7 mg the development of resistance was largely but not completely abrogated; 0-35 mg resulted in a lesser degree of abrogation, and 0-09 mg or 0-02 mg had little or no effect.

Animals↗
PubMed1975

Effect of local injection of Corynebacterium parvum on the growth of a murine fibrosarcoma.

Local injection (i.e. injection at the site of tumour inoculation) of strains of C. Parvum which have a significant anti-tumour effect when given systemically (i.e. intravenously or, in the case of subcutaneous tumour transplant, intraperitoneally) strongly inhibits the growth of isogeneic transplants of a fibrosarcoma in intact CBA mice but has little or no effect on subcutaneous transplants of the same tumour in T-cell deprived mice. The anti-tumour effect of local injection of C. parvum, unlike that of systemic injection in this particular tumour system, thus appears to be T-cell dependent.

Animals↗
PubMed1975

A comparative study of anaerobic Coryneforms. Attempts to correlate their anti-tumour activity with their serological properties and ability to stimulate the lymphoreticular system.

Various strains of anaerobic coryneforms and the closely related Propionibacteria have been compared in vivo with respect to their anti-tumour activity. Their effectiveness has been correlated with their serological relationship and to some extent with their ability to stimulate the lymphoreticular system. Organisms belonging to Corynebacterium acnes groups I and II and C. avidum group IV were active anti-tumour agents, although of varying effectiveness. These strains are serologically closely related and all produce a soluble cross-reacting antigen. The single C. granulosum group III strain which we tested, an unclassified coryneform, and the classical Propionibacteria did not cross-react with the main group and had little or no anti-tumour activity. At the high dose (0.7 mg) we used, all strains, whether they inhibited tumour development or not, enhanced clearance of colloidal carbon and stimulated production of an inflammatory peritoneal exudate; at lower dosage the results were too variable to permit valid comparison. At the higher dose anti-tumour activity of a strain appeared to correlate best with ability to produce splenomegally and decrease red cell volume in the blood.

Anaerobiosis↗
PubMed1974

Anti-tumour effect in vitro of lymphocytes and macrophages from mice treated with Corynebacterium parvum.

Cells from the spleen, lymph node, peripheral blood and peritoneal exudate of mice treated with C. parvum were tested for their ability to inhibit tumour growth in vitro. The peritoneal exudate cells from C. parvum treated mice were extremely effective in inhibiting tumour growth whereas the spleen and peripheral blood cells were only moderately so. In contrast, the lymph node cells caused only a modest inhibition of tumour growth at a very high effector to target cell ratio. Spleen cells from normal mice also exerted a moderate anti-tumour effect.

Animals↗