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Biomedical subjects

D K Ryan

Publications and source records attributed to D K Ryan.

7 recordsLinked to original sources
PubMed1997

3-(4-Carboxybenzoyl)quinoline-2-carboxaldehyde, a reagent with broad dynamic range for the assay of proteins and lipoproteins in solution.

This paper describes the application of 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA), a sensitive fluorogenic reagent for detection of amines, to the assay of proteins in solution. The sensitivity and dynamic range of CBQCA in the determination of protein concentration is modulated by the number of accessible amines present in the protein assayed. Thus, this method bears the same limitations as other reagents used in fluorogenic assays based on fluorescent amine adducts such as those obtained with fluorescamine or o-phthaldialdehyde, or of other spectrophotometric methods, where the color development is determined by the abundance in the protein of certain amino acids. However, in comparison to other fluorescence-based protein detection methods, CBQCA has proven to be an extremely sensitive reagent with a very broad, essentially linear dynamic range, capable of detecting from 10 ng to 150 micrograms of protein (in a 100- to 200-microL assay volume). The CBQCA reagent also functions well in the presence of substances, such as lipids, known to interfere in many other protein determination methods.

Benzoates↗
PubMed1997

Routine diagnosis of large granular lymphocytic leukaemia by Southern blot and polymerase chain reaction analysis of clonal T cell receptor gene rearrangement.

AIMS: To compare the polymerase chain reaction (PCR) assay with standard Southern blot (SB) hybridisation for the detection of clonal T cell receptor (TCR) gene rearrangements in large granular lymphocyte (LGL) proliferations; to evaluate the reliability and practicality of the methods for routine diagnostic use; and to determine the sensitivity of the PCR method. METHODS: Blood lymphocytes were isolated from 12 patients with persistent CD3+CD8+ lymphocytosis with LGL morphology. Clonal rearrangements of the TCR gene were demonstrated by SB hybridisation with a TCR beta constant probe, and by PCR amplification of portions of the TCR beta and TCR gamma genes. RESULTS: Monoclonal TCR beta gene rearrangements were detected in eight patients (67%) by PCR analysis and five patients (42%) by SB hybridisation. PCR analysis also showed that seven patients (58%) had monoclonal TCR gamma gene rearrangements. All cases which had TCR beta clonal rearrangements shown by SB hybridisation were similarly identified by PCR. Sensitivity tests suggested that the TCR beta PCR technique was capable of detecting clonality in as little as 50 pg of DNA. The TCR beta primers could detect one clonal cell in approximately 200 or more normal cells (< 0.5%), a sensitivity level that at least doubles that of the SB hybridisation technique. CONCLUSIONS: The use of PCR technology proved to be superior to SB hybridisation for the routine investigation of suspected cases of LGL leukaemia. Nine patients (75%) in this study were found to have TCR beta and/or TCR gamma monoclonal gene rearrangements. This approach is ideal for distinguishing between reactive and clonal LGL proliferation in a routine diagnostic laboratory.

Blotting, Southern↗
PubMed1993

Gut contents: a significant contaminant of Mytilus edulis whole body metal concentrations.

Ingested matter can have a significant effect on whole body metal concentration measurements in Mytilus edulis. Depuration of mussels in clean seawater for 36 h prior to dissection eliminates most of these contaminating gut contents. Depuration followed by metal analyses is the most direct method of determining mussel tissue metal bioburdens. After being transplanted into a plume of primary treated sewage effluent in Salem Harbor, Massachusetts for 32 days, Al, Cr, and Fe concentrations in depurated mussels were significantly lower than those determined for either non-depurated mussels or for depurated mussels to which fecal concentrations of Al, Cr, and Fe were added back in. Although mathematical methods developed by both Ouellette (1978) and Boehm et al. (1988) could be applied to non-depurated mussels in order to correct for errors associated with gut metal contamination, these indirect methods were not as reliable as depuration prior to analysis.

Animals↗
PubMed1990

Effect of intraocular lens optic design on posterior capsular opacification.

Secondary capsular opacification is a common complication of extracapsular cataract extraction. We have done a retrospective study of 1,040 consecutive posterior chamber implants using four optic designs. The annual incidence of capsular opacification requiring capsulotomy was calculated to see if the optic design was a possible factor. The laser ridge and laser "peg" optics each had a cumulative capsulotomy rate of over 40.0% at three years and the convex-plano optic, over 40.0% at five years. Optics of plano-convex/biconvex designs had a cumulative capsulotomy rate of 5.0% at three years and 6.5% at five years. These results strongly suggest that capsular opacification is retarded when there is broad adhesion of the lens optic to the posterior capsule.

Aged↗
PubMed1986

Comparative studies of host-cell reactivation, cellular capacity and enhanced reactivation of herpes simplex virus in normal, xeroderma pigmentosum and Cockayne syndrome fibroblasts.

Host-cell reactivation (HCR) of UV-irradiated herpes simplex virus type 2 (HSV-2), capacity of UV-irradiated cells to support HSV-2 plaque formation and UV-enhanced reactivation (UVER) of UV-irradiated HSV-2 were examined in fibroblasts from 4 patients with Cockayne syndrome (CS), 5 with xeroderma pigmentosum and 5 normals. All UV-survival curves for HSV-2 plaque formation showed 2 components. HCR was similar to normal for the XP variant strain and the 2 CS strains tested, but substantially reduced in the 4 excision-deficient XP strains. The capacity of UV-irradiated fibroblasts to support HSV-2 plaque formation was determined by UV-irradiating fibroblast monolayers with various doses of UV and 48 h later, infecting the monolayers with unirradiated HSV-2. The D37 values for the delayed-capacity curves so obtained were in the range 8.6-12.4 J/m2 for the normal strains, 2.8-3.2 J/m2 for the CS strains, 6.7 J/m2 for an XP variant strain and between 0.3 and 1.5 for the XP excision-deficient strains tested. These results indicate that delayed capacity for HSV-2 plaque formation is a more sensitive assay than HCR in the detection of cellular DNA-repair deficiency for XP and CS. For the examination of UVER, fibroblasts were irradiated with various UV doses and subsequently infected with either unirradiated or UV-irradiated HSV and scored for plaque formation 2 days later. UVER expression was maximum when the delay between UV-irradiation of the cells and HSV infection was 48 h. The magnitude of UVER expression was also found to be dependent on the UV dose to the cells and increased with increasing UV dose to the virus. Using a UV dose to the virus resulting in a plaque survival of about 10(-2) on unirradiated cells, the the maximum UVER factor had a mean value of 1.3 for the normal strains following a dose of 15 J/m2 to the cells. Somewhat higher UVER values were found for all the patient strains tested and resulted from lower UV doses to the cells than for normal strains. Maximum UVER factors for the CS strains ranged from 2.2 to 3.3 at a dose of 5 J/m2 to the cells, for the XP excision-deficient strains; 2.1 to 2.6 at doses of 0.5 to 2.5 J/m2 to the cells and for the XP variant strain tested; 2.5 at UV dose of 10 J/m2 to the cells.

Adolescent↗
PubMedDate not supplied

Temporary blindness associated with traumatic asphyxia.

Traumatic asphyxia is an uncommon syndrome of craniocervical cyanosis, facial petechiae, and subconjunctival hemorrhages following severe crush injury to the thorax. Ocular manifestations of the syndrome have rarely been reported. A 42-year-old male sustained temporary blindness in association with traumatic asphyxia. Completely normal vision returned within 24 hours of injury. The pathogenesis of this unique finding probably involves transient retinal vein hypertension and reflex vasospasm in the retina.

Adult↗