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Biomedical subjects

D Roberts

Publications and source records attributed to D Roberts.

At least 307 records · Page 17Linked to original sources
PubMed1989

Three-dimensional reconstruction of the foot from computed tomography scans.

Recently developed computer programs create a new type of image from the sections created in computed tomography. These images look like actual photographs of internal structures. The authors describe the process of three-dimensional reconstruction in nonmathematical terms, and provide examples of its use in imaging the bones of the foot. They demonstrate the technique's ability to resolve small details, and its usefulness in displaying articular surfaces.

Computer Graphics↗
PubMed1989

Venous thrombosis in the neck. The role of real time ultrasound.

Real time ultrasound is being increasingly used in the diagnosis of venous thrombosis. We have studied its role in six patients with jugular and/or subclavian vein thrombosis and conclude that ultrasound is a useful, non-invasive first line imaging technique and may negate the need for venography in this small but important group of patients.

Adult↗
PubMed1988

Growth and morbidity in children in a remote aboriginal community in north-west Australia.

As part of a wider social and environmental impact study, we have investigated the current state of health and nutrition in children who were living in a remote Aboriginal community in far north-west Australia. There was evidence of widespread mild-to-moderate malnutrition and a high prevalence of infections, particularly of the respiratory and gastrointestinal tracts, and trachoma. Low birth weight was significantly associated with the presence of undernutrition at five years of age. Our results suggest that malnutrition in utero during infancy and in early childhood and the factors which cause it may impair the growth of young Australian Aborigines permanently.

Anthropometry↗
PubMed1988

Tn10 transposition promotes RecA-dependent induction of a lambda prophage.

We present evidence that Tn10 transposition, or a closely correlated event, induces expression of bacterial SOS functions. We have found that lambda prophage induction is increased in Escherichia coli lambda lysogens containing increased Tn10 transposase function plus single or multiple copies of an appropriate pair of transposon ends. This increase occurs by the normal pathway for prophage induction, which involves RecA-mediated cleavage of the phage lambda repressor protein. We also present evidence that Tn10 promotes induction of expression of the E. coli sfiA gene. Tn10 transposes by a nonreplicative mechanism. We propose that the signal for RecA protease activation and SOS induction is generated by degradation of the transposon donor molecule and suggest that SOS induction is biologically important in helping a cell undergoing transposition to repair and/or recover from damage to the transposon donor chromosome.

Bacteriophage lambda↗
PubMed1988

A genetic analysis of the rose-gespleten region (68C8-69B5) of Drosophila melanogaster.

We describe a genetic analysis of the region 68C8-69B5 defined by Df(3L)vin-7. We have induced 35 new lethal mutations in this region, which together with 20 existing lethal mutations, visible mutations, genes identified by protein products and one gene deduced from complementation data fall into 37 complementation groups in this 35-band interval. Using existing and newly induced deficiencies we have assigned these to 11 intervals defined by deficiency breakpoints. Those mutations which fell in the same breakpoint interval as the Lsp-2 gene, which codes for the abundant larval serum protein 2, were the subject of detailed study. None was rescued by the active Lsp-2 gene transformed on to chromosome II and we conclude that, as yet, we have no lethal mutations of Lsp-2.

Animals↗
PubMed1988

Reduction of post-thoracotomy pain by cryotherapy of intercostal nerves.

In a prospective study, 144 patients undergoing thoracotomy were randomized to two groups: In 71 cases cryoanalgesia was applied intraoperatively to the intercostal nerves above and below the incision to relieve postoperative pain, and 73 (control group) received bupivacaine-adrenaline intercostal blockade at the end of the operation. The amount of administered narcotic and mild analgesics, the visual analogue pain scores, the need for further intercostal blockade and the number of postoperative bronchoscopies to clear retained secretion were significantly less in the cryoanalgesia group than in the controls. There were no late nerve complications after cryoanalgesia, which is recommended for routine use in thoracotomy.

Analgesia↗
PubMed1988

Cutaneous microcirculation and blood rheology following cardiopulmonary bypass. Laser Doppler flowmetric and blood cell rheologic studies.

In 23 patients undergoing coronary artery bypass grafting, measurements of cutaneous blood flow were made with laser doppler flowmetry. Simultaneously blood was sampled for measurement of red cell filtration rate (RFR) and plasma-white cell filtration rate (P-WFR). The cutaneous blood flow showed significant overall reduction postoperatively. When the saphenous vein or internal mammary artery was used as bypass graft, the reduction in skin blood flow at the sites from which the vessels were taken was significantly greater than in contralateral, undisturbed sites. RFR and P-WFR were also significantly reduced postoperatively, and these changes showed significant concomitance with the fall in laser doppler flow (LDF%). On postoperative day 6 there was some improvement in LDF% and RFR but further slight deterioration in P-WFR. The study indicated that surgical trauma locally reduces cutaneous blood flow and that trauma to blood cells following cardiopulmonary bypass can contribute to this reduction.

Cardiopulmonary Bypass↗
PubMed1988

Association between arrhythmias and reduced red cell deformability following cardiopulmonary bypass.

In 56 patients undergoing open-heart surgery, trauma to the red cells (reduced deformability) during cardiopulmonary bypass (CPB) was monitored by estimating reduction in red cell filtration rate (RFR). Treatment-requiring arrhythmias (atrial tachyarrhythmia and ventricular tachycardia) appearing more than 24 hours postoperatively were associated with RFR reduction after CPB. The incidence of arrhythmia was 31% in the patients with less than 25% fall in RFR, 53% in those with greater than 25% fall and 81% when the RFR reduction was greater than 75%. RFR fall preceded appearance of arrhythmia.

Arrhythmias, Cardiac↗
PubMed1988

Dispensing by the community pharmacist: an unstoppable decline?

After posing the question ;Is your chemist really necessary?' this article demonstrates that the original role of the retail chemist - the preparation and safe dispensing of medicines - has become eroded. Furthermore, it is shown that the proposed new community roles are currently being carried out by other members of the primary care team. Finally, it is argued that the retail pharmacist may not give value for money and that doctor dispensing is a less expensive and safer alternative.

Community Pharmacy Services↗
PubMed1988

Potential for fecundin to influence the reproductive performance of merino ewes in Western Australia.

Four experiments were conducted at different locations in Western Australia to evaluate the effectiveness of immunizing young (maiden, 1 1/2 year old) and adult Merino ewes with Fecundin to improve their reproductive performances. The ovulation rates of immunized maiden ewes was increased (0.06-0.30) above that of untreated ewes in both experiments 1 and 2. However, there were no significant improvements in the marking percentages for the immunized ewes with the differences between the untreated and immunized ewes ranging from -16.4 to 5.8%. In comparison with untreated ewes immunization 6 and 2 weeks before the start of joining depressed ewe fertility by 26.1% whereas immunization 8 and 4 weeks before the start of joining did not significantly affect fertility. The availability of oat grain ad libitum prior to parturition and during early lactation did not improve the survival of lambs born to immunized ewes. In experiments 3 and 4 immunization of adult Merino ewes increased their ovulation rates (0.41-0.63) above untreated controls and tended to increase the proportion of pregnant ewes which had multiple pregnancies (from -2.3 to 34.2%). The responses at the end of lambing were variable (from -19.8 to 37.5% lambs marked) with high lamb mortalities occurring in some experiments. There was no adverse effect on the reproductive performances following consecutive annual immunizations over 3 years and the absence of treatment for 1 year did not prevent a response in the following year.

Aging↗
PubMed1988

Induction of delayed-type hypersensitivity responses to PPD: dendritic cells in synergy with 5-hydroxytryptamine can substitute for macrophages.

We describe the use of 5-hydroxytryptamine (5HT) as an adjuvant in the induction of the delayed-type hypersensitivity (DTH) response to purified protein derivative (PPD). Based upon our previous studies with antigen-pulsed macrophages (M phi), we have shown that both the Day 2 early (2 hr) reaction and the Day 3 (24 hr) reaction are augmented if 5HT is incorporated into the priming injection. Furthermore, we have confirmed that in contrast to M phi, antigen-pulsed dendritic cells (DC) fail to prime the early (2 hr) component of DTH. However, DC do prime the early response if injected along with 5HT. A peripheral 5HT antagonist, ICS 205-930, inhibits both the M phi-mediated and the 5HT/DC-primed reactions. These findings support the hypothesis that DTH reactions require a cascade of both inflammatory and immunological signals, and that in mice vascular permeability mediated via 5HT is important in the early phase of the reaction.

Adjuvants, Immunologic↗
PubMed1987

Infertile or childless by choice? A multipractice survey of women aged 35 and 50.

Eleven general practitioners examined the medical records of all women on their lists born in 1950 (617 patients) and 1935 (533 patients) to determine the prevalence of childlessness and specialist consultations about infertility. Eighty eight (14.3%) of the women born in 1950 and 41 (7.7%) of those born in 1935 were childless. Sixty eight women born in 1950 (11.0%) and 17 born in 1935 (3.2%) were considered childless by choice. Involuntary childlessness was found in 20 (3.3%) of the women born in 1950 and 24 (4.5%) born in 1935. Forty two (6.8%) of the women born in 1950 had consulted a specialist about infertility as compared with 19 (3.6%) born in 1935. This study found a significant increase in voluntary childlessness among the younger women; there was no evidence of a change in the prevalence of involuntary childlessness despite the increasing demand for specialist referral, which appeared to be made by women who were parous or destined to become so.

Adult↗
PubMed1987

Effect of indomethacin on arterial oxygenation in critically ill patients with severe bacterial pneumonia.

The effect of indomethacin (1 mg/kg) on gas exchange was studied in ten patients with hypoxaemic respiratory failure precipitated by bacterial pneumonia. Mean arterial oxygen tension (PaO2) improved significantly (79 +/- 16 mm Hg to 98 +/- 20 mm Hg) but the response varied between patients: five showed substantial responses (27-42 mm Hg), three lesser responses (7-9 mm Hg), and two no response. Similar changes were found in the alveolar-arterial oxygen gradient and the ratio of PaO2 to fractional inspired oxygen concentration. In two responders studied further, PaO2 had fallen to baseline values 4-6 h later and a repeat indomethacin challenge again increased PaO2 by greater than 25 mm Hg with concomitant changes in pulmonary shunt. There were no significant changes in the other gas-exchange or haemodynamic variables measured and there was no clear reason for the variability in response to indomethacin. These results suggest a role for products of the cyclo-oxygenase pathway of arachidonic acid metabolism in the pathogenesis of hypoxaemia in patients with severe bacterial pneumonia.

Acute Disease↗