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Biomedical subjects

D W Harris

Publications and source records attributed to D W Harris.

At least 19 recordsLinked to original sources
PubMed2001

Can we use video images to triage pigmented lesions?

BACKGROUND: Advances in telemedicine permit consultations where the doctor and patient are at different sites. OBJECTIVES: To determine whether this technology could be used to triage referrals of pigmented lesions to a dermatology out-patient clinic, and thereby assist in managing the ever increasing number of lesions being referred. METHODS: When patients attended clinic, a clinical diagnosis of their pigmented lesion was made and recorded. A still image of each lesion was subsequently taken from a video camera using a PC card, and stored. These images were subsequently viewed in conjunction with the general practitioner's referral information and designated as 'warrants referral' or 'does not warrant referral'. For each lesion this decision was compared with the clinical diagnosis made during the live consultation in the clinic (the 'gold standard'). Clinical diagnoses designated as warranting referral were malignant melanoma, basal cell carcinoma, keratoacanthoma, atypical naevus and pyogenic granuloma (due to the potential clinical confusion with amelanotic melanoma). Lesions that were not considered to warrant referral included benign melanocytic naevus, seborrhoeic keratosis, dermatofibroma, congenital naevus, solar lentigo, actinic keratosis and various other benign conditions. RESULTS: In total, 819 lesions were evaluated, resulting in a mean sensitivity of 81% and specificity of 73% for the technique. CONCLUSIONS: We feel that the overall sensitivity of 81% is encouraging as regards the use of such a technique as a triage tool, but that the inability to examine the whole patient or palpate the lesions is a major drawback in the safe triage of patients with pigmented lesions.

Adolescent↗
PubMed2001

Can we safely diagnose pigmented lesions from stored video images? A diagnostic comparison between clinical examination and stored video images of pigmented lesions removed for histology.

Rapid expansion of communication technology has permitted the clinician to perform a consultation with a patient located at a different site. Assuming adequate diagnostic accuracy, it could theoretically be possible to use telemedical techniques as a triage tool. Images of pigmented lesions sent by the primary care physician could be viewed by the consultant dermatologist, and those with banal lesions spared from attending clinic. Previous studies assessing diagnostic accuracy of images of lesions have used 'face-to-face' diagnoses as the 'gold standard'. We set out to compare diagnostic accuracy of image examination compared with that of clinical examination, using histological examination as the diagnostic benchmark. We found that pigmented lesions may be diagnosed as accurately by stored video image evaluation as by conventional clinical examination. None of the malignant skin tumours was misdiagnosed as benign in either group. Whilst these results are encouraging in terms of the clinical safety of store-and-forward imaging, the inability to examine the whole patient or to palpate the lesions may limit the acceptability of the technique severely. Further evaluation of the cost : benefit ratio of such a system to the health care provider must be undertaken before considering this technique as a potential adjunct to managing outpatient referrals.

Adolescent↗
PubMed1999

Mental health outcomes in dually diagnosed individuals with mental retardation assessed with the MMPI-168(L): case studies.

Recently it has been shown that oral administration of the MMPI-168(L), with simplified explanations of the items provided when needed, can reveal information related to personality and psychopathology in many individuals with mental retardation. The results of repeated administrations of the inventory to 7 clients residing in an institutional setting over a period exceeding 3 years in some cases are presented here. It is argued that results obtained by repeated administration the MMPI-168(L) can reveal information concerning changes in mental health status for many individuals with mental retardation.

Adolescent↗
PubMed1998

Analysis of multiplexed short tandem repeat (STR) systems using capillary array electrophoresis.

The profiling of polymorphic short tandem repeat (STR) markers is being applied to human identification, parentage testing and genetic mapping. Reliable genotyping of these markers is facilitated by polymerase chain reaction (PCR) amplification and high-resolution electrophoretic separation. Capillary array electrophoresis (CAE) offers very rapid, high-resolution separation of the amplified DNA and potential for automated sample processing not realized employing conventional slab-gel electrophoresis. The use of CAE to type DNA samples amplified at 11 genetic loci in multiplex profiles is presented. Two sets totaling 208 samples were amplified in a multiplex fashion using AmpFlSTR-Blue or AmpFlSTR-Green I and analyzed in a blind study using CAE. With the exception of one sample, the CAE genotyping results were in complete agreement with results obtained using a single-capillary system or two slab-gel electrophoresis systems. The sample, genotype TH01 7/10, migrated similar to TH01 6.3/9.3 allele sizes, which suggested a potential band migration shift. The recommended approach to such an observation is to analyze the sample again. The sample was rerun and correct genotype verified. Allelic ladder samples were analyzed multiple times by CAE to determine sizing accuracy and precision. The sizing of over 240 allelic ladder samples yielded an average within-run precision of +/- 0.13 bp and between-run precision of +/- 0.21 bp for fragments up to 350 bp. The CAE protocols permit processing of up to 96 multiplex STR samples in under 70 min.

Alleles↗
PubMed1997

Rapid sizing of polymorphic microsatellite markers by capillary array electrophoresis.

Genetic mapping and DNA sequencing projects could potentially be completed more rapidly by using capillary array electrophoresis (CAE) systems running 48-96 capillaries simultaneously. Currently, multiplex polymerase chain reaction (PCR) and multicolor fluorescent dye-labeling strategies are used to generate DNA profiles containing 18-24 genotypes per sample. By using 4-color fluorescence detection and these multiplex PCR strategies, a CAE system has the capacity to generate up to 5.5 million genotypes per year. CAE offers extremely fast, high-resolution separation of DNA and more automated sample processing than conventional systems because the labor-intensive slab-gel pouring and sample-loading steps are eliminated. We used a prototype CAE system in an ongoing linkage analysis study of inherited deafness in Mediterranean families. CA-repeat markers linked to deafness susceptibility genes on chromosomes 7, 11 and 13 were analyzed and DNA profiles generated which contain 6 markers per color. Fragment sizes of over 28,000 short tandem repeat alleles and 3200 CA-repeat alleles have been determined by CAE. An average sizing precision of +/- 0.12 base pairs (bp) for fragments up to 350 bp was realized in 1-h runs. In addition, a versatile non-denaturing matrix was used to separate DNA sizing standards, restriction digests, and multiplex PCR samples. Application of this matrix to Duchenne muscular dystrophy exon deletion screening is also described. These CAE approaches should facilitate rapid genotyping of microsatellite markers and subsequent identification of disease-causing mutations.

Base Sequence↗
PubMed1997

Short tandem repeat typing by capillary array electrophoresis: comparison of sizing accuracy and precision using different buffer systems.

Polymorphic microsatellite markers are widely used in gene discovery and mapping, human identification, agricultural genetics, and diagnosis of triplet-repeat expansion disorders. Reliable genotyping of these markers requires polymerase chain reaction (PCR) amplification and very-high-resolution electrophoresis. Capillary array electrophoresis offers extremely fast, high-resolution separation of DNA and more automated sample processing because labor-intensive slab-gel pouring and sample loading are eliminated. We report a simple, reliable procedure for preparing PCR samples for electrokinetic injection into capillaries using a 96-well tray and float dialysis. We developed an improved sizing standard for genotyping and used it to evaluate systematically the sizing accuracy and precision of low-viscosity, replaceable matrix formulations. Our study sizing over 28,000 alleles yielded an average precision of +/- 0.12 bp for fragments up to 350 bp. Low-viscosity formulations permit low-pressure matrix injection (40 psi) and a turnaround time of 70 min for 48-96 samples.

Alleles↗
PubMed1997

Versatile low-viscosity sieving matrices for nondenaturing DNA separations using capillary array electrophoresis.

The high-resolution separation of double-stranded DNA (dsDNA) has important applications in physical mapping strategies and in the analysis of polymerase chain reaction (PCR) products. Although high-resolution separations of dsDNA by capillary electrophoresis (CE) have been reported, pulsed fields were required to achieve complete resolution of DNA fragments beyond 23 kilobase pairs (kbp). Here, we report a single formulation to separate a broad range (80 bp-40 kbp) of DNA fragments without the use of pulsed fields. We used a low-viscosity sieving medium (ca. 5 cP, at 25 degrees C) based on polyethyleneoxide (PEO) to separate DNA fragments up to 40 kbp. The matrix contained a mixture of 0.5% PEO (Mn 10(6)) to separate fragments up to 1.5 kbp, combined with 0.1% PEO (Mn 8 x 10(6)) to separate fragments between 1-40 kbp, within a single run. All PEO matrix formulations tested were compatible with a variety of intercalating dyes and with two different capillary wall coating methods. We obtained a detection limit of 25 fg of a 200 bp DNA quantitation standard using Vistra Green in the matrix. Resolution was best using short injection times (5 s or less) and low field strengths (approximately 100 V/cm). Sample runs were complete in 70 min, and use of the capillary array electrophoresis (CAE) system permitted high-throughput DNA analysis. The size range separated is approximately 10 times greater than with conventional slab gel separations.

Coloring Agents↗
PubMed1996

Development of a high-volume in situ mRNA hybridization assay for the quantification of gene expression utilizing scintillating microplates.

A high-volume plate-based in situ hybridization assay has been developed, utilizing Amersham Cytostar-T scintillating microplates. This assay reliably detects specific mRNA transcripts at the level of 10-20 copies per cell. Radiolabeled antisense riboprobes specific for c-fos and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as well as nonhomologous vector-derived control probes were used to compare mRNA levels in quiesced rat A10 smooth muscle cells after stimulation with platelet-derived growth factor (PDGF). Maximal c-fos induction occurred following stimulation of A10 cells with 30 ng/ml of PDGF, corresponding to a signal from the c-fos probe of 700 cpm. The nonhomologous control background of 50 cpm and the GAPDH signals of 1700 cpm were independent of stimulation with PDGF or serum. Using PDGF, at 30 ng/ml, quiesced cells were stimulated at various times to provide an induction time course for c-fos mRNA which peaked at 30 min and returned to basal levels within 2 h. Comparison with parallel Northern blotting experiments showed this in situ assay to be at least 20-fold more sensitive and much more rapid to perform.

Animals↗
PubMed1996

Skin surface lipids in HIV-positive patients with and without seborrheic dermatitis.

BACKGROUND: Seborrheic dermatitis (SD) is a frequent complication of infection with the human immunodeficiency virus (HIV). Most studies examining the cause of SD have concentrated on the roles of Pityrosporum ovale and sebaceous lipids. Previous studies of skin surface lipid from patients with SD have produced conflicting results, with some authors reporting an abnormal lipid composition and others finding little or no abnormality. METHODS: The composition of skin surface lipid was studied in 15 HIV-positive and 10 HIV-negative men with SD, in 14 HIV-positive men without SD, and in 16 unaffected controls. Total lipids were extracted from unaffected forehead skin into petroleum ether and separated into lipid classes by thin layer chromatography. The lipid classes were quantitated by densitometry after charring with sulfuric acid. RESULTS: Patients, HIV-positive with SD, had significantly lower proportions of free fatty acid (FFA) and higher levels of triglyceride than normal controls. Patients, HIV-positive without SD, had a significantly increased proportion of FFA compared to HIV-positive patients with SD. Patients with SD, both HIV-positive and HIV-negative, had a similar pattern of skin surface lipid. Levels of FFA were lower and those of triglyceride higher than in the patients unaffected by SD, whether HIV-positive or not. There was no significant difference found between groups in free cholesterol, wax esters, and squalene. CONCLUSIONS: Abnormalities of skin surface lipid composition may play a part in the development of SD in both HIV-positive and HIV-negative men.

Adult↗
PubMed1996

Pharmacological characterization of U-101387, a dopamine D4 receptor selective antagonist.

Dopamine D2-like receptors play an important role in the pharmacotherapy of psychotic disorders. Molecular and cellular techniques have identified distinct gene products (D2-long, D2-short, D3 and D4) displaying the D2 receptor pharmacology. However, the contribution of each subtype in antipsychotic effects of or their physiological role remain unclear. Here we describe the pharmacological effects of a selective D4 antagonist, U-101387. U-101387 displayed moderately high affinity (Ki = 10 nM) and selectivity for the dopamine D4.2 receptor expressed in clonal cell lines. It lacked measurable affinity for not only other dopamine receptors but also noradrenalin, serotonin and histamine receptor families (Ki > 2000 nM). It fully and dose-dependently antagonized quinpirole-induced cAMP inhibition (without producing any effect by itself) in stably transfected cells. U-101387 also displayed excellent oral bioavailability, brain penetration and other pharmacokinetic characteristics. Unlike classical neuroleptics (e.g., haloperidol), U-101387 neither blocked acute behavioral effects of amphetamine or apomorphine nor did it alter spontaneous locomotion by itself. Additionally, U-101387 was without effect in behavioral and biochemical tests predictive of extrapyramidal and neuroendocrine side effects. Consistent with the lack of autoreceptor function of D4, acute administration of U-101387 failed to alter dopamine neuronal firing by itself or reverse the inhibition produced by dopamine agonists and to affect monoamine turnover in areas innervated by the mesencephalic or hypothalamic dopamine neurons. However, U-101387 potently induced c-fos mRNA expression in the infralimbic/ventral prelimbic cortex to a level similar to that produced by the atypical antipsychotic, clozapine. This is consistent with the predominantly cortical distribution of the D4 receptor. Taken together, these results demonstrate that the D4-selective antagonist, U-101387, produces effects that are distinct from those of the nonselective D2 antagonists as well as D3-preferring agents. U-101387 offers a unique tool to understand the role of dopamine D4 receptors in diseases involving central dopamine systems.

Amphetamines↗
PubMed1994

The Southern blot. An update.

This article is devoted to the recent advances made in the Southern blotting technique, which is used for the detection of gel-fractionated DNA molecules following transfer to a membrane. The latest practical improvements made to the techniques of Southern blotting, probe labeling, and hybridization are discussed. Among the most significant advances are: new membranes, transfer methods, probe labeling, and rapid hybridization. Detailed protocols show the application of these improvements in this widely used technique.

Biotechnology↗
PubMed1994

Rapid staining with carcinoembryonic antigen aids limited excision of extramammary Paget's disease treated by Mohs surgery.

Extensive extramammary Paget's (EMPD) disease of the perineum in a 68-year-old man was treated by Mohs surgery. To facilitate identification of involved tissue a rapid staining carcinoembryonic antigen was used. This technique proved a useful adjunct to conventional hemotoxylin-eosin (H&E) stains. It was especially useful in highlighting involvement in areas of marked dysplasia/artifact where discrimination is often difficult. It is recommended that such a technique offers considerable benefits over H&E staining when confronted by such tissue morphology.

Aged↗
PubMed1994

Characterization of U-92016A as a selective, orally active, high intrinsic activity 5-hydroxytryptamine1A agonist.

The purpose of the present study was to characterize U-92016A [(+)-R)-2-cyano-N,N-dipropyl-8-amino-6,7,8,9-tetrahydro-3H-benz[e] indole] as a 5-hydroxytryptamine (5-HT)1A receptor agonist and to compare its activity with that of standard 5-HT1A receptor agonists. U-92016A binds with high affinity to human 5-HT1A receptors expressed in Chinese hamster ovary cells (Ki = 0.2 nM). Radioligand binding studies also indicate that U-92016A is selective for the 5-HT1A receptor over other biogenic amine receptors. In Chinese hamster ovary cells expressing the human 5HT1A receptor, U-92016A decreased the forskolin-induced increase in cyclic AMP synthesis and had an intrinsic activity of 0.82 relative to 5-HT. U-92016A potently decreased rectal temperature in mice. The maximum temperature decrease was significantly greater than that observed for 8-hydroxy-di-n-propyl aminotetralin, buspirone, gepirone, ipsapirone or flesinoxan. U-92016A also elicited the 5-HT-mediated syndrome in rats and resulted in a dose-related decrease in 5-hydroxytryptophan accumulation. The compound also decreased arterial blood pressure in spontaneously hypertensive rats and inhibited sympathetic nerve activity in cats. In these assays U-92016A displayed excellent potency and a long duration of action. U-92016A also inhibited the firing of dorsal raphe 5-HT neurons and was active in two social interaction assays. The p.o. bioavailability of U-92016A was calculated to be 45%. Taken together, these data indicate that U-92016A is a metabolically stable, p.o. active 5-HT1A receptor agonist with an exceptionally high degree of intrinsic activity.

5-Hydroxytryptophan↗
PubMed1992

Efficacy of traditional Chinese herbal therapy in adult atopic dermatitis.

There has been considerable interest in traditional Chinese herbal therapy (TCHT) as a new treatment for atopic dermatitis. To establish the efficacy and safety of this treatment, a daily decoction of a formula containing ten herbs that has been found to be beneficial in open studies was tested in a double-blind placebo-controlled study. 40 adult patients with longstanding, refractory, widespread, atopic dermatitis were randomised into two groups to receive 2 months' treatment of either the active formulation of herbs (TCHT) or placebo herbs, followed by a crossover to the other treatment after a 4-week washout period. The main outcome measures were extent and severity of erythema and surface damage as judged by standardised body scores. The patients' own assessments of the overall response to treatment were also sought. The geometric mean score for erythema at the end of active treatment was 12.6 (95% confidence interval [CI] 5.9 to 22.0) and at the end of the placebo phase was 113 (65 to 180). The geometric mean score for surface damage was 11.3 (5.8 to 21.8) and 111.0 (68 to 182), respectively. The 95% CI for the mean geometric ratio for the two values with active treatment was 0.04 to 0.22 for erythema (p less than 0.0005) and 0.04 to 0.27 for surface damage (p less than 0.0005). Of the 31 patients who completed the study and expressed a preference, 20 preferred that phase of the trial in which they received TCHT whereas 4 patients preferred placebo (p less than 0.02). There was a subjective improvement in itching (p less than 0.001) and sleep (p less than 0.078) during the TCHT treatment phase. No side-effects were reported by the patients although many commented on the unpalatability of the decoction. TCHT seems to benefit patients with atopic dermatitis. Palatability of the treatment needs to be improved and its safety assured.

Administration, Oral↗