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Biomedical subjects

T Burt

Publications and source records attributed to T Burt.

At least 19 recordsLinked to original sources
PubMed2005

Sertraline in generalized anxiety disorder: efficacy in treating the psychic and somatic anxiety factors.

OBJECTIVE: The objective was to study the efficacy of sertraline on symptoms of psychic and somatic anxiety in patients suffering from moderate-to-severe generalized anxiety disorder (GAD). METHOD: Out-patients with DSM-IV GAD were randomized to 12 weeks of double-blind treatment with placebo. The psychic and somatic anxiety factors of the Hamilton Anxiety Rating Scale (HAM-A) and the Quality of Life, Enjoyment, and Satisfaction Questionnaire were analyzed. RESULTS: Treatment with sertraline resulted in significantly greater last observation carried forward (LOCF)-endpoint improvement than placebo on both the HAM-A psychic and somatic anxiety factors. At LOCF-endpoint, all items on the HAM-A psychic factor were more improved on sertraline than placebo, as were three of seven items on the somatic factor. Reduction of secondary depressive symptoms was more correlated with endpoint improvement in quality of life than either psychic- or somatic anxiety. CONCLUSION: Sertraline treatment demonstrated efficacy for both the psychic and somatic anxiety symptoms of GAD.

Adult↗
PubMed2004

The practical application of reflectance spectrophotometry for the demonstration of haemoglobin and its degradation in bruises.

AIMS: To develop a non-invasive method to demonstrate the presence of haemoglobin and its degradation products in bruises in live human subjects for the purposes of objectively assisting in the determination of the age of a bruise. METHODS: The cuvette holder unit of a Cary 100 Bio UV-Visible Spectrophotometer was replaced with the manufacture's fibre optic cable and optical reflectance probe. The probe was placed on the skin surface. The absorption spectrum from 780 to 380 nm was collected and transformed into the first derivative. Calculation of the first derivative permits absorption attributed to haemoglobin degradation (primarily to bilirubin, but also haemosiderin) to be separated from absorption by haemoglobin. First derivative and colorimetry values, expressed as CIEL*a*b data, were derived from scans of 50 bruises. RESULTS: The fibre optic cable and probe allowed the spectrophotometer to collect reproducible absorption spectra of bruises in the skin of living subjects. A bruise at three days has greater negative first derivative values at 480 and 490 nm than does a fresh bruise, indicating the local degradation of haemoglobin. Correlation between the first derivative and the CIEL*a*b "b" values in a series of bruises indicates that the yellow colour in a bruise is proportional to the amount of local haemoglobin breakdown. CONCLUSION: The ability to demonstrate the presence of haemoglobin and measure its degradation in bruises in living human subjects by a non-invasive method has not been described previously, and may be of use in the objective ageing of bruises for forensic purposes.

Bilirubin↗
PubMed2001

The identification and characterization of hydrazinyl urea-based antibacterial agents through combinatorial chemistry.

An effort to identify novel inhibitors of peptidoglycan synthesis with antibacterial activity resulted in the discovery of a series of biaryl urea-based antibacterial agents through isolation of a by-product from a mixture-based combinatorial library of semi-carbazones and subsequent parallel synthesis efforts. The compounds were shown to possess broad spectrum antibacterial activity against gram-positive drug resistant pathogens, and showed apparent specificity for disruption of the bacterial cell wall biosynthesis pathway.

Anti-Bacterial Agents↗
PubMed2001

The effects of vagus nerve stimulation on cognitive performance in patients with treatment-resistant depression.

BACKGROUND: Chronic vagus nerve stimulation (VNS) is effective in the management of treatment-resistant epilepsy. Open-trial evidence suggests that VNS has clinically significant antidepressant effects in some individuals who experience treatment-resistant major depressive episodes. However, limited information regarding the effects of VNS on neurocognitive performance exists. OBJECTIVE: The primary aim of this study was to determine whether VNS leads to neurocognitive deterioration. METHOD: A neuropsychological battery was administered to 27 patients with treatment-resistant depression before and after 10 weeks of VNS. Thirteen neurocognitive tests sampled the domains of motor speed, psychomotor function, language, attention, memory, and executive function. RESULTS: No evidence of deterioration in any neurocognitive measure was detected. Relative to baseline, improvement in motor speed (finger tapping), psychomotor function (digit-symbol test), language (verbal fluency), and executive functions (logical reasoning, working memory, response inhibition, or impulsiveness) was found. For some measures, improved neurocognitive performance correlated with the extent of reduction in depressive symptoms, but VNS output current was not related to changes in cognitive performance. CONCLUSIONS: Vagus nerve stimulation in treatment-resistant depression may result in enhanced neurocognitive function, primarily among patients who show clinical improvement. Controlled investigation is needed to rule out the contribution of practice effects.

Adolescent↗
PubMed2000

Vagus nerve stimulation: a new tool for brain research and therapy.

Biological psychiatry has a long history of using somatic therapies to treat neuropsychiatric illnesses and to understand brain function. These methods have included neurosurgery, electroconvulsive therapy, and, most recently, transcranial magnetic stimulation. Fourteen years ago researchers discovered that intermittent electrical stimulation of the vagus nerve produces inhibition of neural processes, which can alter brain electrical activity and terminate seizures in dogs. Since then, approximately 6000 people worldwide have received vagus nerve stimulation for treatment-resistant epilepsy. We review the neurobiology and anatomy of the vagus nerve and provide an overview of the vagus nerve stimulation technique. We also describe the safety and potential utility of vagus nerve stimulation as a neuroscience research tool and as a putative treatment for psychiatric conditions. Vagus nerve stimulation appears to be a promising new somatic intervention that may improve our understanding of brain function and has promise in the treatment of neuropsychiatric disorders.

Brain↗
PubMed2000

Donepezil and related cholinesterase inhibitors as mood and behavioral controlling agents.

Acetylcholinesterase inhibitors (ChEIs) enhance neuronal transmission by increasing the availability of acetylcholine in muscarinic and nicotinic receptors. This effect is believed to be responsible for the beneficial and protective effects of ChEIs on cognition in patients with Alzheimer's disease (AD). Effects of ChEIs on mood and behavior have also been reported. Earlier observations were limited by the exclusive availability of intravenous forms of administration, the short half-life of the formulations, and the high frequency of peripheral side effects. The introduction, in recent years, of better tolerated and less invasive compounds has rekindled the interest in cholinergic central nervous system mechanisms and has given rise to studies in areas other than cognition. The ChEI donepezil has been involved in the largest number of studies and positive reports. Preliminary observations suggest the possible value of ChEIs in the management of behavioral dysregulation, apathy, irritability, psychosis, depression, mania, tics, and delirium and in the diagnosis of depression, panic, and personality disorders.

Affect↗
PubMed2000

Learning and memory in bipolar and unipolar major depression: effects of aging.

OBJECTIVE: The goal of this study was to examine the effects of aging on neuropsychological functions in bipolar and unipolar major depression. BACKGROUND: Earlier studies suggested that neurocognitive deficits in mood disorder patients correlate with duration and severity of illness and also that bipolar disorder has a more virulent course than unipolar disorder. We hypothesized that elderly patients with bipolar disorder will demonstrate greater neurocognitive dysfunction than young patients with bipolar disorder and elderly patients with unipolar disorder. METHOD: A battery of tests of general intelligence and learning and memory was administered to 79 inpatients with major depression referred for electroconvulsive therapy. With patients 60 years of age and older defined as elderly, there were 29 young and 24 elderly unipolar patients and 13 young and 13 elderly bipolar patients. RESULTS: Unipolar and bipolar patients did not differ in measures of general intelligence or global cognitive status. Generally, across tests of memory, young bipolar patients exhibited the best performance and elderly bipolar patients exhibited the poorest performance. CONCLUSIONS: The results suggest that over the course of their illness, patients with bipolar disorder experience greater deterioration in memory functions than patients with unipolar disorder. Longitudinal studies are required to support the preliminary findings of this cross-sectional study.

Adult↗
PubMed1999

Mania associated with St. John's wort.

BACKGROUND: St. John's wort, the popular herbal remedy touted as an antidepressant, is generally thought to be benign, with few reported side effects. Given its possible efficacy as an antidepressant, evaluation of its propensity to cause affective switching should be evaluated. METHODS: This report presents two cases of mania temporally associated with the use of St. John's wort (hypericum). RESULTS: As with other antidepressant agents, St. John's wort may precipitate hypomania, mania, or an increased cycling of mood states, particularly in patients with occult bipolar disorder. CONCLUSIONS: Because the majority of people who take this popular over-the-counter preparation do so without formal psychiatric evaluations, risk of hypericum-induced mania may be significant. Physicians should screen patients for a history of hypomania or mania before recommending use of St. John's wort for depression.

Adult↗
PubMed1999

Donepezil in treatment-resistant bipolar disorder.

BACKGROUND: A considerable percentage of patients with bipolar disorder do not respond or do not tolerate conventional treatment. Cholinesterase (ChE) inhibitors have been suggested to possess depressogenic and antimanic properties. METHODS: We report a case series of treatment-resistant bipolar patients (n = 11) to whom we administered the ChE inhibitor donepezil. Four patients met criteria for current manic episode, 5 for mixed episode, 1 for hypomanic episode, and 1 for major depressive episode. Donepezil was added to current medication on an openlabel basis. Ratings were based on a retrospective chart review. RESULTS: Of the 11 patients, 6 (54.5%) demonstrated marked improvement (improvement in CGI-S > or = 2), 3 (27.2%) demonstrated slight improvement, 1 did not respond, and 1 did not tolerate the medication. Among those patients who had marked improvement (i.e., responders, n = 6), improvement was observed within 2 weeks or less in 5 of them (83%). Patients experienced only minor side effects. CONCLUSIONS: These pilot data suggest the efficacy and safety of donepezil in the treatment of bipolar disorder. To our knowledge this is the first published report on the use of donepezil in the treatment of mood disorders. Controlled, randomized, double-blind studies are necessary to validate these preliminary observations.

Adult↗
PubMed1998

Medial smooth muscle cell loss in arterial allografts occurs by cytolytic cell induced apoptosis.

OBJECTIVE: Experimental arterial allografts, used as models of chronic rejection, undergo marked loss of smooth muscle cells (SMC) from their media prior to the development of occlusive, intimal proliferative lesions. Medial SMC loss has been described in human heart transplants, and may be related to the development of occlusive coronary lesions which are the hallmark of chronic rejection. This SMC loss does not exhibit the characteristics of necrotic cell death. We sought to determine whether medial SMC loss in arterial allografts occurs by apoptosis. We further investigated these allografts for cytolytic cell-derived inducers of apoptosis, Finally, we compared two different strain combinations to assess the impact of varying histoincompatability on medial SMC loss. METHODS: Evidence for internucleosomal DNA degradation, which is characteristic of apoptosis, was sought by the in situ terminal deoxynucleotidyl transferase nick end labelling (TUNEL) method carried out on Lewis to Fisher rat femoral artery transplants (disparate at minor loci only) and Brown Norway to Lewis aortic transplants (fully disparate at major and minor loci). Isografts (Lewis to Lewis) served as controls. In a separate series of experiments graft mRNA was extracted and analysed by reverse transcription-polymerase chain reaction (RT-PCR) with primers for molecular inducers of apoptosis (TNF-alpha, Fas ligand, perforin, and granzyme-B) which are derived from cytolytic cells known to be present in allografts. RESULTS: Allograft media contained large numbers of TUNEL stained nuclei in both strain combinations. Neither isografts nor ungrafted femoral artery segments stained positive for apoptosis. RT-PCR on whole allografts in both strain combinations revealed sustained upregulation of perforin, granzyme-B, Fas-ligand and TNF-alpha mRNA concomitant with medial SMC loss. Autografts demonstrated sustained up regulation of TNF-alpha, and perforin, but only brief upregulation of granzyme-B, and no upregulation of Fas-ligand. CONCLUSIONS: These data strongly suggest that medial SMC loss in allograft arteriopathy occurs by apoptosis. Further, RT-PCR data indicate that cytolytic cell-derived inducers of apoptosis are upregulated in these grafts and may be accountable for medial SMC apoptotic cell death. Finally, fully-disparate (Brown Norway to Lewis) and minor-only incompatible (Lewis to Fisher) strain combinations both resulted in marked intimal proliferation, medial SMC loss by apoptosis, and similar patterns of expression of cytolytic cell derived inducers of apoptosis. Insofar as intimal proliferative lesion-formation may be dependent on medial damage (as in arterial-injury models), understanding the mechanism of medial SMC loss may provide a novel therapeutic approach to human cardiac transplant arteriopathy.

Animals↗
PubMed1997

Further evidence for visual landmark involvement in the pigeon's familiar area map

In previous experiments suggesting that previewing visual landscapes speeds homing from familiar release sites, restricted access to olfactory cues may have artefactually encouraged homing pigeons, Columba liviato resort to visual landmark orientation. Since evidence for the role of visual landmarks in wide-ranging avian orientation is still equivocal, Braithwaite & Guilford's (1991, Proc. R. Soc. Lond. Ser. B245, 183-186) 'previewing' experiments were replicated: birds were allowed or denied visual access to a familiar site prior to release, but allowed ample access to olfactory cues. In experiment 1, allowing birds to preview familiar sites for 5 min prior to release enhanced homing speeds by about 12%. In experiment 2, modified to reduce between-day effects on variation, previewing enhanced homing speeds by about 16%. These experiments support the conclusion that visual landmarks remote from sight of the loft are an important component of the familiar area map, although the nature of the landmarks and how they are encoded remain to be determined.

Journal Article↗
PubMed1997

The Family Environment Scale: reliability and normative data for an adolescent sample.

The Family Environment Scale has been used extensively in family research since first being published. However, despite its appeal both conceptually and empirically, doubts have been raised over the scale's reliability. This article presents normative and reliability data for the Family Environment Scale from a large, combined sample of adolescents. Means and standard deviations were generally found to be in line with those reported in the scale's manual; however, estimates of internal consistency for most subscales could be considered inadequate for research purposes.

Adolescent↗
PubMed1996

Cognitive deficits in Machado-Joseph disease.

Cognitive function was examined in 6 patients with genetically confirmed Machado-Joseph disease (MJD) and 15 age- and ethnically matched controls using a series of subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB), a touch screen-based testing system previously validated in a number of movement and neurodegenerative disorders. The MJD patients had deficits in visual attentional function that were characterized by a slowing of the processing of visual information when task demands were high and an inability to shift attention to previously irrelevant stimulus dimensions to discriminate between complex stimuli. Tests of learning and visual memory were normal. These results demonstrate that specific cognitive deficits occur in patients with MJD, independent of motor dysfunction, and these deficits may reflect disruption to frontosubcortical pathways.

Adult↗
PubMed1996

Machado-Joseph disease in east Arnhem Land, Australia: chromosome 14q32.1 expanded repeat confirmed in four families.

Four kindreds of east Arnhem Land Australian aboriginal people from Groote Eylandt and adjacent communities display symptoms of a similar spinocerebellar degeneration (multiple-system degenerative disease). The familial pattern indicates an autosomal dominant inheritance, though with varying penetrance in different families. This condition is clinically and pathologically consistent with Machado-Joseph disease (MJD), and there is the possibility of Portuguese ancestry. These families exhibit anticipation, particularly in the case of paternal inheritance, with those with earlier age of onset presenting a clinical pattern consistent with MJD type I. There was no expansion of the CAG repeat region of the SCA1 gene in these families. The demonstration of expansion of the CAG repeat on chromosome 14q32.1 in all four families confirms the diagnosis of MJD.

Australia↗
PubMed1994

1H-NMR measurement of fractional dissociation of imidazole in intact animals.

The alphastat hypothesis states that intracellular acid-base status is regulated to maintain constancy of the fractional dissociation of intracellular protein and enzyme imidazole-histidine (alpha-imidazole). A major drawback of this theory has been the lack of a means to directly measure alpha-imidazole in intact animals. We developed a method for directly measuring alpha-imidazole in intact unanesthetized animals using 1H-nuclear magnetic resonance spectroscopy (NMR). We measured carnosine alpha-imidazole of white skeletal muscle from intact unanesthetized newts at three body temperatures (10, 20, and 30 degrees C). alpha-Imidazole remained constant, approximately 0.56, with alterations in body temperature, whereas intracellular pH (pHi) changed significantly (-0.015 U/degrees C), affirming the validity of the imidazole alphastat hypothesis for this tissue. This method was also used to determine the pK values of the imidazole moiety of carnosine and the imidazole moiety alone over a temperature (T) range 4-40 degrees C. The pK values of carnosine differed from those of imidazole, but the delta pK/delta T was the same. pHi was also determined using 31P-NMR and found to be the same as that calculated from carnosine alpha-imidazole values. Therefore Pi and carnosine share a similar pHi environment. We describe a novel technique to directly measure alpha-imidazole in intact tissue.

Animals↗