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Biomedical subjects

M J Booth

Publications and source records attributed to M J Booth.

18 recordsLinked to original sources
PubMed2005

Simple optimization procedure for objective lens correction collar setting.

We present a new method for setting a coverglass correction collar on an objective lens. Axial scans across the interface between the specimen volume and the slide are used together with a quantitative function of merit to determine the optimum setting of the correction collar. The method, which simplifies the adjustment for the user and reduces photobleaching, was implemented within the software environment of a scanning microscope system.

Journal Article↗
PubMed2004

Transfection-free and scalable recombinant AAV vector production using HSV/AAV hybrids.

Adeno-associated virus (AAV) vectors are highly efficient tools for use in gene therapy. Current production methods rely on plasmid transfection and are not generally considered amenable to scale-up. To improve recombinant AAV (rAAV) vector production in terms of both final titre and simplicity, we constructed recombinant herpes simplex virus (HSV) vectors, either disabled (ICP27 deleted) or nondisabled, encoding the AAV rep and cap genes. We also integrated an rAAVGFP construct into the nondisabled vector and also into a second pair of HSV vectors (disabled and nondisabled) not expressing rep and cap. Transgene incorporation and expression was confirmed by Southern and Western blot, respectively. Optimal double-infection ratios were established for disabled and nondisabled pairs of rep/cap-expressing and rAAVGFP-containing vectors, resulting in up to 1.55 x 10(12) rAAV capsids and 4 x 10(8) expression units from approximately 1 x 10(7) BHK producer cells. Functionality of the prepared vector was confirmed by the detection of abundant green fluorescent protein (GFP) expression following injections of rAAV preparations into the rat brain. This paper therefore describes a simple, efficient, and transfection-free rAAV production process based on the use of HSV and not relying on a proviral cell line that, with appropriate scale-up, could yield quantities of rAAV sufficient for routine clinical use.

Animals↗
PubMed2004

Low-cost, frequency-domain, fluorescence lifetime confocal microscopy.

We describe the theory and implementation of a frequency-domain fluorescence lifetime confocal microscope using switched diode laser illumination. Standard, communications-type, radio-frequency electronics are used to provide inexpensive modulation references and to perform phase-sensitive detection. This allows the rapid acquisition of fluorescence intensity and lifetime images and their display in real time. We show fluorescence lifetime images of bead objects and fluorescence lifetime images of biological specimens from a single confocal scan.

Electronics↗
PubMed2004

Simulation of specimen-induced aberrations for objects with spherical and cylindrical symmetry.

Wavefront aberrations caused by the refractive index structure of the specimen are known to compromise signal intensity and three-dimensional resolution in confocal and multiphoton microscopy. However, adaptive optics can measure and correct specimen-induced aberrations. For the design of an adaptive optics system, information on the type and amount of the aberration is required. We have previously described an interferometric set-up capable of measuring specimen-induced aberrations and a method for the extraction of the Zernike mode content. In this paper we have modelled specimen-induced aberrations caused by spherical and cylindrical objects using a ray tracing method. The Zernike mode content of the wavefronts was then extracted from the simulated wavefronts and compared with experimental results. Aberrations for a simple model of an oocyte cell consisting of two spherical regions and for a model of a well-characterized optical fibre are calculated. This simple model gave Zernike mode data that are in good agreement with experimental results.

Animals↗
PubMed2004

Measurement of specimen-induced aberrations of biological samples using phase stepping interferometry.

Confocal or multiphoton microscopes, which deliver optical sections and three-dimensional (3D) images of thick specimens, are widely used in biology. These techniques, however, are sensitive to aberrations that may originate from the refractive index structure of the specimen itself. The aberrations cause reduced signal intensity and the 3D resolution of the instrument is compromised. It has been suggested to correct for aberrations in confocal microscopes using adaptive optics. In order to define the design specifications for such adaptive optics systems, one has to know the amount of aberrations present for typical applications such as with biological samples. We have built a phase stepping interferometer microscope that directly measures the aberration of the wavefront. The modal content of the wavefront is extracted by employing Zernike mode decomposition. Results for typical biological specimens are presented. It was found for all samples investigated that higher order Zernike modes give only a small contribution to the overall aberration. Therefore, these higher order modes can be neglected in future adaptive optics sensing and correction schemes implemented into confocal or multiphoton microscopes, leading to more efficient designs.

Animals↗
PubMed2001

Refractive-index-mismatch induced aberrations in single-photon and two-photon microscopy and the use of aberration correction.

We examine the effects of aberrations induced by a refractive index mismatch on the signal level and resolution of single-photon (1-p) and two-photon (2-p), conventional and confocal scanning microscopes. In particular, we consider the aberrations introduced by an interface between oil/glass and water. Resolution is defined in terms of enclosed fluorescence, rather than full-width half-maximum, revealing more useful information for heavily aberrated point spread functions (PSFs). It is shown that, at large focusing depths, the resolution of 2-p conventional and 1-p confocal microscopes are almost identical. The benefits of aberration correction are examined by removing Zernike aberration modes. With aberration correction, the best resolution is found for 1-p confocal and 2-p confocal modes. An approximation based upon geometrical optics is also introduced which shows that the axial resolution of heavily aberrated PSFs is roughly proportional to focusing depth.

Microscopy, Fluorescence↗
PubMed2001

Temporary remission of disseminated paecilomycosis in a German shepherd dog treated with ketoconazole.

Disseminated mycosis caused by Paecilomyces varioti in a female German shepherd dog presented with chronic forelimb lameness is described. Radiographs of the swollen carpal joint revealed geographic lysis of the radial epiphysis. Diagnosis was based on cytological demonstration of fungal hyphae and chlamydiospores, as well as fungal culture of fluid obtained by arthrocentesis. Temporary remission was characterised by markedly improved clinical signs and laboratory parameters, following treatment with ketoconazole. The dog was euthanased 9 months after the initial diagnosis, following the diagnosis of multifocal discospondylitis. This appears to be the longest described period of temporary remission obtained with treatment in dogs with paecilomycosis. Clinical, clinicopathological and necropsy findings of this disease in another German shepherd dog are briefly described.

Animals↗
PubMed2000

Strategies for the compensation of specimen-induced spherical aberration in confocal microscopy of skin.

We consider various strategies for confocal imaging of human skin which seek to reduce the effects of the specimen-induced aberrations. We calculate the spherical aberration introduced by the stratified structure of skin and show how the confocal signal is affected when attempting to image at various depths within the dermis. Using simple methods it is shown how images might be improved by compensating for the induced aberration. The methods include the use of an iris to reduce the pupil area, changing the refractive index of the immersion medium and using a lens with variable coverglass correction.

Artifacts↗
PubMed1998

Continuous wave excitation two-photon fluorescence microscopy exemplified with the 647-nm ArKr laser line.

We report on efficient two-photon fluorescence imaging in beam scanning microscopy by exciting UV dyes at the 647-nm line of a continuous wave ArKr mixed gas laser. For a numerical aperture of 1.4 (oil), we used an illumination power of up to 210 mW at the sample. High-resolution images were obtained for DAPI-labelled cell nuclei within 4-60 s. Our method is a simple two-photon alternative to UV confocal imaging with the potential of becoming a very useful feature of laser scanning microscopy.

Animals↗
PubMed1998

Nurse anesthetist reaction to the unexpected or untimely death of patients in the operating room.

Certified registered nurse anesthetists (CRNAs) experience the unexpected death of the their patients much differently than other nurses. Unlike all other nurses, they are held directly responsible for maintaining their patients' physiologic parameters in the face of surgical and pharmacologic insults and not only for selecting the types of anesthetic and adjuvant drugs but also for manipulating their doses on a minute-to-minute basis. Four factors significantly enhance their stress: the presence of an unrescinded advance medical directive and/or do not resuscitate order; the harvesting of vital organs; psychologic factors, including distractions, errors in clinical judgment, fatigue, boredom, or lack of vigilance; and legal threats. Unless CRNAs have significant coping skills firmly in place, any of these stresses may cause them to deteriorate physically, emotionally, or professionally.

Attitude of Health Personnel↗
PubMed1998

Atypical dermoid sinus in a chow chow dog.

A case of multiple dermoid sinuses in the dorsal cervical and craniothoracic regions in an adult chow chow dog is described. One sinus did not open on the skin surface. This is the first reported case of the condition in this breed and the first time absence of the sinus opening on the skin is described. The use of the term pilonidal sinus to describe this condition is challenged.

Animals↗
PubMed1998

Malignant fibrous histiocytoma of the deep peri-articular tissue of the stifle in a dog.

A Belgian shepherd dog aged 4 years and 9 months was presented with acute onset of non-weight bearing lameness and stifle effusion of the left hind limb, caused by the deep form of a malignant fibrous histiocytoma originating in the deep musculature and fascia surrounding the stifle joint. The tumour progressed rapidly in the tissues along the femoral diaphysis with marked periosteal new bone formation. Cytology of a stifle joint aspirate revealed numerous large polygonal neoplastic cells with considerable anisocytosis and anisokaryosis. These cells were present in clusters, with cytoplasmic projections between the cells, but occasionally also occurred singly. Several cells contained multiple cytoplasmic vacuoles and occasional giant cells were also encountered. Adequate tumour-free margins were not possible with radical limb amputation and the dog was euthanased. Macroscopically the tumour appeared as an extensive pale tan, firm mass with scattered small haemorrhages and foci of yellow discolouration. Histologically the tumour consisted of dense neoplastic expanses or multiple nodules, composed of spindle-shaped fibroblastic cells, polygonal histiocytic cells or cell clusters and scattered giant cells with 2-3 nuclei. The polygonal neoplastic cells were frequently present around and invading lymphatics and blood vessels, causing neoplastic emboli. This is the 1st report of the clinical behaviour, radiography and cytology of the deep form of malignant fibrous histiocytoma in the dog.

Animals↗
PubMed1997

Identification of serine/threonine protein kinases secreted by Trichinella spiralis infective larvae.

Serine/threonine protein kinase activity was identified in excretory/secretory (ES) products of Trichinella spiralis infective larvae, via phosphorylation of exogenous and endogenous substrates. Protein kinase activity was identified as an authentic secretory product via blockade of release into culture medium by brefeldin A. Enzyme activity was reductant-dependent, and the relative resistance to a panel of inhibitors suggested that it could not be readily assigned to any of the major documented subfamilies of serine/threonine protein kinases. There was no evidence for protein tyrosine kinase activity in ES products. The major phosphorylated proteins in this compartment resolved at 50 and 55 kDa by SDS-PAGE, and are therefore designated pp50/55. These proteins contained mainly phosphoserine, and appear to represent differentially glycosylated variants of a 35 kDa polypeptide, modified via the addition of three and four N-linked oligosaccharides, respectively. An autophosphorylation assay following separation by SDS-PAGE identified two protein kinases of 70 and 135 kDa in ES products.

Animals↗
PubMed1995

Detection of chromosome 11 alterations in blood and bone marrow by interphase cytogenetics in mantle cell lymphoma.

The t(11;14)(q13;q32) translocation is a consistent chromosome change in mantle cell lymphomas. This study investigates the application of fluorescent in situ hybridization (FISH) with chromosome painting probes for interphase cytogenetic analysis in patients with mantle cell lymphomas. Chromosome 11 paints have been able to show splitting of the chromosome signal consistent with the t(11;14) translocation in interphase cells from bone marrow and blood of patients with mantle cell lymphomas. These include some in clinical remission. The chromosome probes conjugated with fluorescent molecules are hybridized with patient's DNA allowing the easy detection of chromosome 11 abnormalities with fluorescent-light microscopes. Interphase FISH has a higher sensitivity and is quicker than standard metaphase cytogenetics. This may be beneficial in rapid detection of chromosome 11 abnormalities, assisting in the diagnosis of mantle cell lymphomas. In addition, detection of a clonal population of cells is possible.

Bone Marrow↗
PubMed1991

Report of the National Commission on Nurse Anesthesia Education. The past, present and future of accreditation.

The role of accreditation in regulating the educational community is looked at in relation to the impact educators, university administrators, professional associations and governmental agencies have had on its effectiveness. Accreditation is viewed as a tool educational institutions can use to assess their actions and as a vehicle for initiating change when it is needed.

Accreditation↗
PubMed1991

Current and future perspectives regarding the framework for nurse anesthesia education: within the framework of allied health departments.

The pros and cons of relocating collegiate nurse anesthesia programs to colleges of nursing, medicine or allied health are examined from the standpoint of a program that has already made such a move. Educators generally feel that such movement is appropriate, because of the academic enrichment it brings to the nurse anesthesia profession, a factor that far outweighs any confusion over degrees that might result.

Education, Nursing, Graduate↗