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Biomedical subjects

A Todd

Publications and source records attributed to A Todd.

18 recordsLinked to original sources
PubMed1995

Deletion analysis of minimal sequence requirements for autonomous replication of ors8, a monkey early-replicating DNA sequence.

We have generated a panel of deletion mutants of ors8 (483 bp), a mammalian autonomously replicating DNA sequence, previously isolated by extrusion of nascent monkey (CV-1) DNA from replication bubbles active at the onset of S phase. The deletion mutants were tested for replication function by the DpnI resistance assay, in vivo, after transfection into HeLa cells, and in vitro. An internal fragment of 186-bp that is required for autonomous replication function of ors8 was identified. This fragment, when subcloned into pBR322 and similarly tested, was capable of autonomous replication in vivo and in vitro. The 186-bp fragment contains several repeated sequence motifs, such as the ATTA and ATTTAT motifs, occurring three and five times, respectively, the sequences TAGG and TAGA, occurring three and seven times, respectively, two 5'-ATT-3' repeats, a 44-bp imperfect inverted repeat (IR) sequence, and an imperfect consensus binding element for the transcription factor Oct-1. A measurable sequence-directed DNA curvature was also detected, coinciding with the AT-rich regions of the 186-bp fragment.

Animals↗
PubMed1994

Autonomous replication in vivo and in vitro of clones spanning the region of the DHFR origin of bidirectional replication (ori beta).

Plasmids containing the origin of bidirectional replication (ori beta) of the Chinese hamster dihydrofolate reductase-encoding gene (DHFR) were tested for autonomous replication in vivo and in vitro. The results show that plasmids pX24 and pneoS13, that contain a 4.8- and a 11.5-kb fragment, respectively, spanning the ori beta region, are able to replicate autonomously in human cells and in a cell-free system that uses human cell extracts. Another plasmid, pX14, containing a 4.8-kb fragment that is immediately adjacent to the ori beta region, also replicated in these two assays.

Animals↗
PubMed1993

The Edinburgh Postnatal Depression Scale: validation for an Australian sample.

One hundred and three post-partum women completed the Edinburgh Postnatal Depression Scale (EPDS) and were interviewed using the Diagnostic Interview Schedule. A cut-off score of 12.5 on the Edinburgh Postnatal Depression Scale identified all nine women who reached criteria for major depression. At this threshold the sensitivity (the percentage of true "cases" identified) of the EPDS was 100%, its specificity (the percentage of true "non-cases" identified as such) 95.7% and its positive predictive value (the percentage of all those tested as positive who were correctly identified as such) 69.2%. Although this study supported the validity of the EPDS, a replication of this study on a larger sample is suggested.

Adult↗
PubMed1991

Pigeon breeders' lung: pigeon intestinal mucin, an antigen distinct from pigeon IgA.

Antigens identified by indirect immunofluorescence staining and specific for sera from patients with pigeon breeders' lung or healthy pigeon breeders, have been isolated from pigeon intestinal mucus. Two antigenic peaks, one pigeon intestinal mucin and the other IgA, were separated by equilibrium centrifugation of water-soluble mucus in a caesium chloride density gradient. Antigenic positive material was identified by a modified double-sandwich ELISA, by inhibition of haemagglutination of turkey erythrocytes and by gel diffusion. Antigenic-positive material co-fractionated on gel-filtration with purified intact and papain digested pigeon mucin, both free of IgA. These studies demonstrate antibodies to two quite different antigens are associated specifically with sera from pigeon breeders, a novel antigen pigeon intestinal mucin and the previously documented pigeon IgA.

Animals↗
PubMed1989

Acute traumatic lateral patellar dislocation.

An unusual case of acute extra-articular patellar dislocation is described in which the patella dislocated laterally, rotated 90 degrees about its vertical axis, and wedged against the lateral femoral condyle. Closed reduction in the emergency department failed and operative intervention was required.

Adolescent↗
PubMed1988

The transfer of zinc across the term dually perfused human placental lobule.

Net zinc transfer between fetal and maternal circulation has been described in the in vitro perfused lobule of the human term placenta. The transfer results in a 3 microM differential between fetal and maternal perfusates which is comparable to estimated values in vivo. Tissue zinc concentration is more than 10 times perfusate concentration and is correlated with zinc flux across the fetal borders of the lobule. Open-circuit studies on net transport of zinc, and upon flow of 65Zn relative to tritiated water (3H2O), indicate these fluxes depend upon the non-protein-bound (free) zinc gradient across the fetal-facing membranes. On the other hand movement across the maternal surface is not related to diffusion gradients of free zinc and is either independent of, or inversely related to, the level of tissue zinc. It is concluded that the uptake of zinc from the maternal perfusate may be coupled to metabolism, whereas its transfer to fetal circulation is linked to the level of free zinc in the tissue.

Female↗
PubMed1986

Amebic infections in asymptomatic homosexual men, lack of evidence of invasive disease.

A survey for enteric infections in 140 asymptomatic homosexual men who attended a community clinic revealed a high prevalence of infection with Entamoeba histolytica (27.1 per cent) and Giardia lamblia (15.7 per cent). In contrast, the prevalence of elevated indirect hemagglutination (IHA) titers (greater than or equal to 1:128), which indicate invasive amebiasis, was low (5.7 per cent). Our findings suggest that only a limited amount of invasive amebic disease is occurring in this group of homosexual men.

Adolescent↗
PubMed1980

Fibre size distribution in the elbow joint nerve of the cat.

The elbow joint nerve, a small branch of the musculocutaneous nerve in the cat, was investigated with low power transmission electron microscopy. By taking a series of overlapping photographs a montage was constructed of the cross section appearance of the complete nerve. Thus, a complete count of the number and sizes of myelinated and unmyelinated fibres was obtained. Two peaks in the distribution of myelinated fibres were consistently found, one at 2-5 micrometers and the other at 8-11 micrometers. The number of unmyelinated fibres was much larger than the number of myelinated fibres, with an average ratio of 4.4:1. This proportion of unmyelinated fibres is higher than that found by earlier workers, but is comparable with that in other peripheral nerves.

Animals↗
PubMed1979

Antianaphylactic agents. 1. 2-(Acylamino)oxazoles.

The synthesis and biological properties of 35 2-(acylamino)oxazoles are described. The majority of the compounds inhibit the release of slow-reacting substance of anaphylaxis (SRS-A) in vitro from sensitized guinea pig chopped lung. In addition, several of the compounds inhibited the release of SRS-A from passively sensitized human chopped lung and protected guinea pigs from the effects of anaphylaxis in a modified Herxheimer test.

Anaphylaxis↗
PubMedDate not supplied

Radiological management of renal trauma.

The radiological and surgical management of renal trauma patients has changed considerably in recent years, partly because of the increasing availability of high technology facilities. This article reviews the imaging examinations employed in the assessment of patients with suspected renal trauma.

Diagnostic Imaging↗
PubMedDate not supplied

Lead in bone: storage site, exposure source, and target organ.

The primary site of lead storage is in bone but relatively little attention has focused on this physiological compartment. Recent advances in measurement technology now permit the direct in vivo quantitative measurement of lead in bone, and this measure has great use in clinical and epidemiologic studies. Lead in bone is not a physiological sink, but can be mobilized back into the circulation in response to normal or pathological changes in mineral metabolism. Bone lead may be a significant source of target organ exposure under certain conditions, such as pregnancy, kidney disease, and menopause. Finally, the accumulation of lead in bone cells may have toxic consequences for bone status, and some of the mechanisms by which lead could affect bone mineral metabolism may also play a role in other target organ effects of lead.

Bone and Bones↗