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Biomedical subjects

D J Bower

Publications and source records attributed to D J Bower.

12 recordsLinked to original sources
PubMed1994

Round atelectasis as a complication of Legionnella pneumonia.

Round atelectasis is a rare lung pseudotumor that is most commonly associated with asbestos-related pleural disease but can result from a variety of chronic pleural diseases. We describe a patient who developed round atelectasis over a period of only several months following an acute pleuropulmonary illness caused by Legionnella pneumophila.

Humans↗
PubMed1989

Homozygous protein C deficiency: early treatment with warfarin.

We present a case of homozygous protein C deficiency with neonatal purpura fulminans and disseminated intravascular coagulopathy (DIC) starting shortly after birth. In addition, the infant had vitreal eye hemorrhages and intraparenchymal brain infarction, apparently as intrauterine events. Within 15 hours of institution of fresh frozen plasma (FFP) infusions the DIC resolved and the progression of purpura fulminans reversed. Warfarin (0.4 mg/kg/day) was started on the fifth day of life, followed by gradual tapering of the FFP infusions. There were no recurrences of purpura, areas of skin necrosis healed without the need for skin grafting, and the areas of brain infarction resolved without apparent sequelae. The eye and brain lesions may be intrauterine events and appear to be a regular feature of this syndrome. Family studies are essential to establish the diagnosis, although there may be no family history of thromboembolic events, as in this case. Homozygous protein C deficiency is a rare disorder, but one in which early recognition and intervention may be lifesaving. Ours is the youngest patient yet reported to be treated with warfarin anticoagulation. We were thus able to avoid the complications of long-term plasma therapy as well as the potential thrombotic complications of central venous catheter placement.

Female↗
PubMed1987

Chromosome organisation in polyploid mouse trophoblast nuclei.

At least one-third of mouse trophoblast cells undergo endoreduplication during the first half of gestation. It has been suggested that the endoreduplicated chromosomes may be polytenised. Here it is shown, using in situ hybridisation to the alpha-1 antitrypsin genes, which map at a unique site, that while there is a tendency for duplicated chromosomes to cluster, this does not involve the complete fusion of replicated chromatids found in fully polytene chromosomes, and in a substantial proportion of homologues the sites on the chromosome arms corresponding to these genes are widely separated. The centromeres do not fuse into a single chromocentre but the possibility is not ruled out that individual chromosomes may be polytenised in the centromeric region. Evidence is also presented showing that endoreduplication in trophoblast nuclei is not accompanied by the formation of new prekinetochore structures, in contrast to the situation in polyploid mouse liver and C127 cells.

Animals↗
PubMed1986

Characterization of a polypeptide associated with coated vesicles and the cytoskeleton which is recognized by a CREST serum.

Serum from an individual with the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dismotility, sclerodactyly, telangiectasia) reacts not only with kinetochores, but also with a cytoplasmic, phosphorylatable polypeptide, which is shown by immunofluorescence in whole cells and immunoelectronmicroscopy in sections to be associated with actin stress fibres in cultured mammalian cells. The antigen shows some variation in molecular weight between species, estimated by immunoblotting to range from 68 to 76 kD between mouse, Chinese hamster, sheep and human cells. Much of the polypeptide copurifies with coated vesicles, of which approx. 5% bound antibody from the serum, as detected by immunogold electronmicroscopy.

Actins↗
PubMed1985

Cellular heterogeneity in the expression of the delta-crystallin gene in non-lens tissue.

RNA transcripts of the delta-crystallin genes, which code for the major chicken lens protein, have been detected at low levels in many non-lens tissues. Here it is demonstrated by in situ hybridisation that these transcripts are concentrated at a high level in small, infrequent clusters of cells in many non-lens tissues. While the nuclei of these cells are very heavily labelled, there is only light labelling of the cytoplasm. The unlabelled cells surrounding the labelled clusters are of similar morphology and staining properties as the labelled cells, and all have the characteristic morphology of cells of the embryonic tissue used. With the exception of neural retina, it is not yet known whether the labelled clusters are found in specific locations in the tissues, or whether they arise at random.

Animals↗
PubMed1983

Chicken lens delta-crystallin gene expression and methylation in several non-lens tissues.

RNA sequences coding for the most abundant chicken lens proteins, delta-crystallin, were detected at very low levels in day old post hatch chick lung, heart, kidney and liver, and in 6 day embryo headless bodies. The pattern of cytosine methylation within the CCGG sequences of the delta-crystallin genes was also examined and shown to vary in several non-lens tissues, from several stages of development. Embryonic neural retina, which expresses a higher level of delta-crystallin RNA than the above tissues, is no less methylated in the sites studied than the tissues which have no association with the eye, and is actually more heavily methylated than the kidney. Thus no obvious correlation was found between undermethylation and gene expression.

Animals↗
PubMed1982

Cytoplasmic RNA sequences complementary to cloned chick delta-crystallin cDNA show size heterogeneity.

Double-stranded complementary DNA (cDNA) sequences were prepared from day-old chick lens total polysomal RNA and inserted into the unique PstI restriction site of the plasmid pBR322. Colonies containing sequences complementary to abundant lens poly(A)-containing RNA sequences were identified by using lens 32P-labelled cDNA. Some of these clones have been characterized as containing delta-crystallin mRNA coding sequences by genomic DNA blot hybridization and RNA blot hybridizations. Hybridization of labelled DNA from such clones to RNA blots detected four size classes of delta-crystallin RNA sequences, although Southern blots indicated that there are probably only two delta-crystallin genes.

Animals↗
PubMed1981

Nonprotein neurotoxins.

Nonprotein neurotoxins are continuing to play a major role as molecular probes in studying nervous processes. They also have clinical importance as some of them, such as saxitoxin and its analogues, are the source of public health problems, or have potential use in therapy. This review covers clinical, biological, pharmacological, and chemical aspects of certain nonprotein neurotoxins, with emphasis on three well-known ones: tetrodotoxin, saxitoxin, and batrachotoxin. The distribution of the toxins is discussed as well as their symptomatology, treatment of affected patients, and effects of their structures on their physiological activity. With so many outstanding problems remaining in neuropharmacology, the study of nonprotein neurotoxins thrives as a fertile area of research.

Animals↗