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S Dale

Publications and source records attributed to S Dale.

At least 19 recordsLinked to original sources
PubMed1992

Pronuclear, cleavage and blastocyst histories in the attempted preimplantation diagnosis of the human hydatidiform mole.

We report a study of fertilization, syngamy and embryonic development in 14 oocytes from a woman with four previous pregnancies involving complete hydatidiform moles. Serial observations of pronuclear movements and syngamy were compared to those in a group of 10 multipronucleate embryos from other patients. One embryo and possibly two others developed normally or near-normally. The others displayed immediate cleavage or had one or three pronuclei. The tripronucleate eggs displayed various anomalous forms of growth. The unipronucleate eggs passed through a double form of syngamy, which might have involved chromosome doubling, and could have developed as androgenetic diploids. We suggest a hypothesis to explain these unusual observations.

Adult↗
PubMed1992

Identification of DNA sequences flanking the breakpoint of human t(14q21q) Robertsonian translocations.

We have employed molecular probes and in situ hybridization to investigate the DNA sequences flanking the breakpoint of a group of t(14q21q) Robertsonian translocations. In all the families studied, the probands were patients with Down syndrome who carried a de novo t(14q21q) translocation. The DNA probes used were two alphoid sequences, alphaRI and alphaXT, which are specific for the centromeres of chromosomes 13 and 21 and of chromosomes 14 and 22, respectively; a satellite III sequence, pTRS-47, which is specific for the proximal p11 region of chromosomes 14 and 22; and a newly defined satellite III DNA, pTRS-63, which is specific for the distal p11 region of chromosome 14. The two alphoid probes detected approximately the same amount of autoradiographic signal on the translocated chromosomes as was expected for chromosomes 14 and 21 of the originating parent, suggesting that there has been no loss of these centromeric sequences during the translocation events. Results with the two satellite III probes indicated that the domain corresponding to pTRS-47 was retained in the translocated chromosomes, whereas the domain for pTRS-63 was lost. These results have allowed us to place the translocation breakpoint between the pTRS-47 and pTRS-63 domains within the p11 region of chromosome 14.

Autoradiography↗
PubMed1991

Duplications of the X chromosome in males: evidence that most parts of the X chromosome can be active in two copies.

We have analysed two duplications of the X chromosome in male patients using chromosome replication and DNA methylation patterns as determinants of the functional status of the duplicated segments. In both cases, the large duplicated regions, Xq12-q22 and Xq26.3-qter, were not inactivated. A review of previously reported male cases revealed that these duplications were also not subject to inactivation. Taken together, the examined duplications cover almost the entire X chromosome except the pericentromeric region and Xq25-26. Thus, most regions of the X chromosome can be present in two functional copies without lethal consequences.

Blotting, Southern↗
PubMed1991

Autoantibodies in primary biliary cirrhosis: analysis of reactivity against eukaryotic and prokaryotic 2-oxo acid dehydrogenase complexes.

Six components of the mammalian 2-oxo acid dehydrogenase complexes have previously been identified as M2 autoantigens in primary biliary cirrhosis. In this report, we present data showing that both polypeptide-specific and cross-reacting antibodies are present in patients' sera. Antibodies reacting with E2 of the pyruvate dehydrogenase complex cross-react with protein X but not with any other mammalian antigen. The main immunogenic region on protein X has been localized to within its single lipoyl domain. Polypeptide-specific antibodies bind to E1 alpha and E1 beta of the pyruvate dehydrogenase complex. Antibodies reacting with the E2 polypeptides of the 2-oxoglutarate dehydrogenase complex and branched-chain 2-oxo acid dehydrogenase complex show some cross-reactivity but do not recognize any of the antigens of the pyruvate dehydrogenase complex. Antibodies against the E2 component of the mammalian pyruvate dehydrogenase complex cross-react effectively with the corresponding protein from yeast but not with E2 from Escherichia coli. Antibody titer against mammalian antigens is significantly higher than against the bacterial antigens, arguing against a bacterial origin for primary biliary cirrhosis.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1991

Nurse, is it ME? Understanding myalgic encephalomyelitis.

Ignored or dismissed for years, myalgic encephalomyelitis (ME) is now recognised as a genuine illness, and sufferers are recommended strict rest until the symptoms of the virus subside. Public understanding of ME is still uncertain, and nurses are ideally placed to provide practical information and support.

Counseling↗
PubMed1990

Digital amputations in neuropathic feet.

A retrospective study was performed on 26 patients who had undergone 27 digital amputations. All of the patients in the study had marked neuropathy. Sixty-five percent of the feet developed new ulcerations following initial hallux amputations, with 53% of the ulcerations occurring at distal digital sites. Fifty-three percent of the patients who had undergone hallux amputations required further amputations secondary to new ulcerations. In contrast, only 10% of the feet with initial lesser digit amputations developed new ulcerations. The authors discuss the biomechanics involved and the possible therapy for preventing these ulcerations and amputations.

Alcoholism↗
PubMed1990

Tomography using a rotating slant-hole collimator and a large number of projections.

A tomographic method using a limited-view angle has been evaluated. In studies using a gamma camera and a rotating 30-degree slant-hole (RSH) collimator, 64 projection images were registered. A special filtered backprojection technique was used for reconstruction of section images parallel to the collimator face. Resolution within such sections was 0.6 cm, 3 cm from the collimator face and 1.3 cm at 18 cm. Depth resolution was 2.2 cm at 3 cm and 5.1 cm at 18 cm. Spacing between section images was regular and geometric distortion negligible. Short-axis section images of a myocardium in vivo were qualitatively comparable or better than those obtained with single-photon emission computed tomography. Degradation in the posterior wall due to attenuation and scatter was less. Section images of the facial bones and a hip joint further demonstrated the tomographic capability of the method.

Algorithms↗
PubMed1990

Thallium-201 myocardial tomography with a rotating slant-hole collimator and a large number of projections.

Tomographic imaging of the myocardium was performed using a gamma camera and a 30-degree rotating slant-hole collimator to register 64 projections from a restricted-view angle. Section images were reconstructed with a two-dimensional filtered backprojection technique. Performance in terms of resolution, effects of misalignment, and three-dimensional activity distribution was evaluated in phantom studies. In a limited clinical study, ten consecutive patients were imaged both with single-photon emission computed tomography (SPECT) and the method described. In the new method, the camera was orientated in the 30 degrees left anterior oblique position with 15 degrees cranial tilt. Due to the short distance from the myocardium to the camera, resolution within reconstructed section images was high, the noise level was comparatively low, and the mean activity level in the posterior wall was significantly higher (p less than 0.005) than in SPECT.

Heart↗
PubMed1989

Centromeric alpha satellite DNA amplification and translocation in an unusually large chromosome 14p+ variant.

We report cytogenetic and molecular studies on a family that carries, in the father, an unusually large chromosome 14p+ variant [WSi-var(14)(p+)] and, in one of his children, a translocation [DSi-der(14)] involving the variant chromosome. Increase in the size of WSi-var(14)(p+) was estimated to be approximately 35% that of a normal chromosome 14. Presence of extra chromosomal material in this variant chromosome was demonstrated by G-banding using trypsin and staining with Leishman, G-banding using bromodeoxyuridine (BrdU) and Giemsa, and R-banding using BrdU and Giemsa. This material was positive using C-banding with BaOH and staining with Giemsa and negative in DAPI/distamycin staining, suggesting that it contained repetitive DNA but probably not of the types found in the heterochromatic regions of chromosomes 1, 9, 15, 16, and Y. Staining of the nucleolus organiser region (NOR) with AgNO3 indicated the retention of the NOR in WSi-var(14)(p+) but not in DSi-der(14). In situ hybridisation of metaphase cells with an alpha satellite DNA probe specific for human acrocentric chromosomes demonstrated a significantly increased amount of centromeric alpha sequences in WSi-var(14)(p+). Most or all of the extra alpha sequences were retained in DSi-der(14), indicating translocation near the very distal end of the enlarged region. The extra alpha satellite DNA material may have originated through amplification of some centromeric segments. The possible role of the amplified DNA in chromosomal translocations is discussed.

Chromosome Banding↗
PubMed1989

Amplification of satellite III DNA in an unusually large chromosome 14p+ variant.

A phenotypically normal male (WSm) was found to have an unusually large short arm of chromosome 14. Increase in the size of this variant chromosome [Wsm-var(14)] was estimated to be approximately 30% that of a normal chromosome 14 by G-banding using trypsin and staining with Leishman. The extra chromosomal material was positive in CBG staining (C-banding using BaOH and staining with Giemsa), suggesting the presence of repetitive DNA. In situ hybridisation using repetitive probes demonstrated this material to be strongly positive for satellite III DNA, and negative for Y-specific heterochromatic DNA. Hybridisation with an alpha DNA probe specific for human acrocentric chromosomes indicated the retention of the centromere, and the absence of alpha DNA in the extra chromosomal material. We propose the origin of the extra chromosomal material in WSm-var(14) to be a result of amplification of contiguous satellite III DNA that is normally present in the short arm of chromosome 14. This variant chromosome does not appear to be associated with the abnormal phenotype in WSm's daughter who is mentally retarded and carries a t(1;?)(q41;?) translocation of chromosome 1.

Chromosome Banding↗
PubMed1989

A study of tolerance to the psychomotor effects of indomethacin in healthy volunteers.

We have examined the effect of single dose indomethacin 50 mg on objective measurements of psychomotor function and whether this effect is altered by pretreatment with indomethacin 25 mg t.i.d. for 7 days in 10 healthy volunteers (5 male, 5 female; age 20-54 y). One hour after a single dose of indomethacin 50 mg there was significant impairment of psychomotor function (critical flicker fusion frequency threshold and choice reaction time) (Wilcoxon p less than 0.05). Pretreatment with indomethacin 25 mg t.i.d. for 7 days prevented this impairment. Thus we conclude that tolerance occurs over the course of a week to the psychomotor effects of indomethacin.

Adult↗
PubMed1986

Purification and characterization of a major allergen from the house dust mite Dermatophagoides farinae.

A major allergen from an extract of the house dust mite, Dermatophagoides farinae, was shown to be extremely heterogenic with respect to charge. A slightly basic component of this allergen with a pI of 8, was purified by isoelectric focusing in two steps. The purified component, denoted antigen 19/20 IIa, seemed to be representative for the allergenic activity of the major allergen. The amino acid analysis suggested that antigen 19/20 IIa had a molecular weight of 9400 and contained one residue of galactosamine. SDS polyacrylamide gel electrophoresis did indicate a somewhat higher molecular weight of 14,500. Antibodies against the purified component cross-reacted with a crude extract of the mite Dermatophagoides pteronyssinus.

Allergens↗
PubMed1985

Ectomography--a tomographic method for gamma camera imaging.

In computerised gamma camera imaging the projections are readily obtained in digital form, and the number of picture elements may be relatively few. This condition makes emission techniques suitable for ectomography--a tomographic technique for directly visualising arbitrary sections of the human body. The camera rotates around the patient to acquire different projections in a way similar to SPECT. This method differs from SPECT, however, in that the camera is placed at an angle to the rotational axis, and receives two-dimensional, rather than one-dimensional, projections. Images of body sections are reconstructed by digital filtration and combination of the acquired projections. The main advantages of ectomography--a high and uniform resolution, a low and uniform attenuation and a high signal-to-noise ratio--are obtained when imaging sections close and parallel to a body surface. The filtration eliminates signals representing details outside the section and gives the section a certain thickness. Ectomographic transverse images of a line source and of a human brain have been reconstructed. Details within the sections are correctly visualised and details outside are effectively eliminated. For comparison, the same sections have been imaged with SPECT.

Brain↗
PubMed1985

Characterization of IgE and IgG antibody responses to Dermatophagoides farinae in rats.

Rats (Brown Norway/Wistar Fu) that were pretreated or not pretreated with cyclophosphamide were immunized with varying amounts of Dermatophagoides farinae allergen extract with alum as adjuvant. Sera were analysed by RAST and by crossed radioimmunoelectrophoresis (CRIE). The highest IgE antibody responses were recorded in animals pretreated with cyclophosphamide that had received low immunizing doses of antigen. The IgE antibody pattern in CRIE was, however, not influenced by the dose of antigen or by cyclophosphamide pretreatment. The IgG pattern in CRIE closely resembled the IgE pattern, demonstrating a similar specificity of the antibody responses of the two isotypes. This indicates non-class specific control of the specificity of antibody responses.

Animals↗