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D Pugh

Publications and source records attributed to D Pugh.

At least 19 recordsLinked to original sources
PubMed2006

Hyper-Rayleigh scattering as a means of monitoring crystal nucleation in solution.

Hyper-Rayleigh scattering is revealed as a very sensitive monitor of cluster formation in solution, and as a means of studying the mechanism of crystal nucleation in molecular species. Two compounds are selected with particularly high second harmonic generation (SHG) powers in the crystalline state and experimental conditions are defined allowing the measurement of the beta value for one of these as 18+/-1x10(-30) esu. It is found to agree with current theoretical prediction of 20x10(-30) esu. In the more powerful of these, two photon induced fluorescence is found to be partly responsible for the SHG. The solubilities of both compounds in methanol are measured and it is observed that these differ by a factor of ten. When the solution concentration is increased beyond 45% of the saturation value, the quadratic coefficient exhibits non-linear behaviour with respect to concentration. Additionally, the widths of the distributions of the HRS signals increase initially with concentration as expected, but, beyond 45% saturation concentrations, these narrow again. These phenomena are interpreted as indicators of cluster formation in these solutions well below saturation concentrations. A future experimental design is proposed in which the coherent component will yield information on the organisation of the molecules in such clusters.

Journal Article↗
PubMed2004

Pharmacokinetics of ceftiofur in llamas and alpacas.

Pharmacokinetic studies of antibiotics in South American camelids are uncommon, therefore drugs are often administered to llamas and alpacas based on dosages established in other domestic species. The disposition of ceftiofur sodium was studied in llamas following intramuscular administration and in alpacas following intravenous and intramuscular administration. Eleven adult llamas were given ceftiofur sodium by intramuscular injection. Each animal received either a standard dose of 2.2 mg/kg or an allometrically scaled dose ranging from 2.62 to 2.99 mg/kg in a crossover design. Ten adult alpacas were given ceftiofur sodium by intravenous and intramuscular injections. Each animal received a standard dosage of 1 mg/kg or an allometrically scaled dose ranging from 1.27 to 1.44 mg/kg i.v., and 1.31-1.51 mg/kg i.m. Blood samples were collected at 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24, 36, 48, and 72 h after administration of the ceftiofur. Pharmacokinetic parameters of ceftiofur in llamas and alpacas were similar following i.m. dosing at both dose levels. The only differences noted were in the total AUC between dose levels, but the AUC/dose values were not different. A sequence effect was noted in the alpaca data, which resulted in lower AUCs for the second dose when the i.v. dose was given first, and with higher AUCs for the second dose when the i.m. dose was given first. Overall, ceftiofur pharmacokinetics in llamas and alpacas are similar, and also very similar to reported parameters for sheep and goats.

Animals↗
PubMed2003

Leptin, tumor necrosis factor-alpha (TNF), and CD14 in ovine adipose tissue and changes in circulating TNF in lean and fat sheep.

Four studies were designed to determine whether 1) tumor necrosis factor-alpha (TNF) and the Lipopolysaccharide (LPS) binding ligand, CD14, are produced by sheep adipose tissue; 2) nutritional reserves and/or short-term fasting affect circulating concentrations of TNF; 3) there is a relationship between TNF and metabolic factors in sheep; and 4) inflammation alters circulating concentrations of leptin. In Exp. 1 and 2, ewes were assigned, based on ultrasonic assessments of last-rib subcutaneous fat measurements to fat (fat thickness > 1 cm; mean = 1.52 +/- 0.03 cm) or thin (fat thickness < 1 cm; mean = 0.25 +/- 0.03 cm) groups. Fat and thin ewes were assigned to fed or fasted groups for a total of four groups (fed-fat; fasted-fat; fed-thin; fasted-thin). Fed-ewes had ad libitum access to feed, and fasted-ewes were prohibited feed 48 h before initiation of sample collection. In Exp. 1, subcutaneous fat samples were collected from just above the last rib for detection of TNF and CD14 mRNA, and immunoreactivity. Tumor necrosis factor-alpha-like immunoreactivity in adipocytes was sparse, more pronounced in cells in fed-ewes than fasted-ewes, and localized to membranes between adjacent cells in nucleated regions. Immunoreactivity for CD14 was minimally observed but present in adipocytes and widely expressed in infiltrating monocytes and epithelial vascular cells. Leptin was detected in adipocytes. In Exp. 2, plasma samples collected every 6 h for 24 h were analyzed for plasma concentrations of TNF. Fat ewes had greater plasma concentrations of TNF than thin ewes (P = 0.039). In Exp. 3, wethers were injected i.v. with interleukin-1beta or TNF. Blood samples were collected every 15 min for 8 h following injection. Plasma concentration of leptin was not affected by treatment (P > 0.39). In Exp. 4, wethers were injected with LPS. Blood samples were collected every 15 min for 8 h following injection. Plasma concentration of leptin was not altered by LPS (P > 0.20). These results provide evidence: 1) of TNF-like immunoreactivity within fat tissue; 2) that elements within fatty tissues have CD14 that may allow adipocyte function to be directly affected by LPS; 3) that plasma concentrations of leptin are not altered by LPS treatment; and 4) that circulating concentrations of TNF are elevated with obesity in sheep.

Adipose Tissue↗
PubMed2000

Flight nursing down under: a perspective.

The purpose of this paper is to describe in the broadest sense the scope of flight nursing practice in the Western Australian context. The Royal Flying Doctor Service--Western Operations provides aeromedical and associated health services, through primary health clinics to persons living in remote and rural areas of Western Australia. Flight nurses provide a significant contribution to fulfilling the core business of the Royal Flying Doctor Service, and in doing so demonstrate that they are able to combine the diversity and speciality that is flight nursing, with the challenges not only of the aviation environment, but of the diversity and remoteness of the physical environment that they may find themselves in.

Aerospace Medicine↗
PubMed1995

Swallowing dysfunction after cardiac operations. Associated adverse outcomes and risk factors including intraoperative transesophageal echocardiography.

The frequency, importance to patient outcomes, and independent predictors of postoperative swallowing dysfunction documented by barium cineradiography were examined in 869 patients undergoing cardiac operations over a 12-month period. Swallowing dysfunction was diagnosed in 34 patients (4% incidence) and was associated with documented pulmonary aspiration in 90% of these patients, increased frequency of pneumonia (p < 0.0001), need for tracheostomy (p = 0.0002), length of stay in the intensive care unit (p = 0.0001), and duration of hospitalization after the operation (p = 0.0001). Independent predictors of postoperative swallowing dysfunction determined by multivariate logistic regression included age (p < 0.001), length of tracheal intubation after the operation (p = 0.001), and intraoperative use of transesophageal echocardiography (p = 0.003). Dysfunctional swallowing after cardiac operations, a serious complication significantly related to postoperative respiratory morbidity and extended length of hospitalization, is more common in older patients. An association between intraoperative use of transesophageal echocardiography and swallowing dysfunction was also observed in our patients.

Aged↗
PubMed1992

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antimicrobial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml respectively; corresponding data for chloramphenicol were 2 ug/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 ug/ml and 0.98 ug/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1992

Cassia alata and the preclinical search for therapeutic agents for the treatment of opportunistic infections in AIDS patients.

In our search for therapeutic agents from natural sources with potential for the treatment of opportunistic infections in patients afflicted with acquired immunodeficiency syndrome (AIDS), we investigated antibacterial and antifungal activities of water extracts of Cassia alata (C. alata). The extracts are traditionally used in Ivory Coast, West Africa to treat bacterial infections caused by Escherichia coli (E. coli), and fungal infections caused by Candida albicans (C. albicans) and dermatophytes. Our working hypothesis was that the extract contains active ingredient(s) which can be isolated, identified and developed into useful antibacterial/antifungal agents for the treatment of opportunistic infections in patients with AIDS. We used the broth dilution and agar dilution methods. Specifically, we focused on E. coli and C. albicans and the effectiveness of the extracts was evaluated relative to those of standard antibacterial agent chloramphenicol and antifungal agent amphotericin B. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the water extract of C. alata against E. coli were 1.6 mg/ml and 60 mg/ml, respectively; corresponding data for chloramphenicol were 2 micrograms/ml and 10 micrograms/ml. Similarly, the MIC and minimum fungicidal concentration (MFC) for the extract against C. albicans were 0.39 mg/ml and 60 mg/ml in contrast to 0.58 micrograms/ml and 0.98 micrograms/ml for amphotericin B. From the dose-response curve plots, the extract had an IC50 of 31 mg/ml for E. coli and 28 mg/ml for C. albicans. The data suggest that C. alata extracts contain agent(s) which have therapeutic potential and might be useful if isolated and developed for the treatment of opportunistic infections of AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1988

Limited cardiopulmonary resuscitation: the ethics of partial codes.

The ethics of limited resuscitative efforts or partial code orders has been the subject of considerable disagreement. The customary objection to partial code orders is that they are ineffective in sustaining life and are intended to deceive the patient and/or patient's family into believing that resuscitation is possible when, in fact, the patient's death is imminent. This article suggests that the ethics and acceptability of partial code orders depend on their intent and that the motivation for partial code orders may differ substantially.

Attitude of Health Personnel↗
PubMed1984

Multiple evanescent white dot syndrome. I. Clinical findings.

We examined 11 young patients with unilateral ocular findings that included multiple white dots at the level of the retinal pigment epithelium (RPE) or the deep retina, vitreal cells, RPE granularity in the macula, reduced visual acuity, electroretinogram (ERG) and early receptor potential (ERP) amplitudes, and fluorescein leakage from disc capillaries and late staining of the RPE. Recovery of visual function included a dramatic improvement in ERG and ERP amplitudes over several weeks. The etiology of this syndrome remains uncertain; there is no definite evidence of systemic involvement.

Adolescent↗
PubMed1984

Multiple evanescent white dot syndrome. II. Electrophysiology of the photoreceptors during retinal pigment epithelial disease.

We performed electrophysiologic studies of photoreceptor function in three patients with multiple evanescent white dot syndrome. During the acute stage, while the visual acuity was impaired, the electroretinogram (ERG) a-wave and the early receptor potential (ERP) amplitudes were profoundly decreased. The ERP regeneration times, determined for one subject, were prolonged. These findings suggest that photoreceptor function was impaired (abnormal a-wave), the effective visual pigment optical density of the outer segments was markedly reduced (ERP amplitude), and visual pigment regeneration was abnormal (ERP regeneration kinetics). During the recovery stage, the ERG and ERP amplitudes and visual acuity returned to normal. Our patients' disease seemed to be primarily of the retinal pigment epithelium (RPE). The decreased visual pigment density and prolonged regeneration kinetics emphasize the physiologic dependence of the sensory retina on the RPE.

Acute Disease↗
PubMed1981

Collagen degradation in an experimental inflammatory lesion: studies on the role of the macrophage.

Collagen degradation was investigated in experimental inflammatory lesions made by implanting fluorescein-collagen sponges into sensitised rats for four days, before transferring them into culture medium. The breakdown of the collagenous structure in vitro by invading cells was inhibited by steroids and related anti-inflammatory drugs whereas non-steroidal anti-inflammatory drugs were without effect. Inhibitors of the lysosomal proteinases were variably effective with chloroquine giving total inhibition, leupeptin and TLCK partial inhibition and aurothioglucose showing no effect. Histochemical studies were made of the distribution of cathepsin B. Beta-glucuronidase and N-acetyl-glucosaminidase in macrophages attached to a collagen substratum. Measurements with specific microelectrodes showed that the microenvironment at the surface of activated macrophages was markedly acidic with values of pH less than 5 between attached cells and collagen substratum. Such conditions would be hostile to neutral collagenases and favour acid (lysosomal) proteinases.

Acetylglucosaminidase↗
PubMed1980

Isolation, synthesis, and pharmacology of metabolites of 1-(3,4-dichlorobenzyl)-3,4,5,6-tetrahydro-2(1H)-pyrimidone.

The metabolism of 1-(3,4-dichlorobenzyl)-3,4,5,6-tetrahydro-2(1H)-pyrimidone, an antianxiety/antidepressant agent, in dogs is reported. Two metabolites, 3-[1-(3,4-dichlorobenzyl)-1-ureido]propanoic acid and 1-(3,4-dichlorobenzyl)uracil, were isolated, characterized, and synthesized. Neither metabolite was acutely toxic, and they did not exhibit antidepressant or antianxiety/anticonvulsant activity.

Animals↗
PubMed1979

The induction of germ tubes in Candida albicans by an intrinsic factor.

The formation of germ tubes in Candida albicans can be initiated by variations in the growth medium and in other environmental factors. Cell-to-cell interaction can also be an essential factor in cell morphogenesis. The crowding together of blastopores of some strains of C. albicans stimulates the development of germ tubes without the addition of extrinsic factors.

Candida albicans↗
PubMed1978

The surface layer of Candida albicans.

The surface of Candida albicans is covered by a mucus layer secreted by the cell. Excess mucus secretion accumulates between the cells, and contains protein, polysaccharides and secreted enzymes. In mature cultures dead cells are trapped in the mucus, and the accumulated mucus and cell debris facilitate the formation of plaque, and the penetration of C. albicans into infected host tissues.

Acid Phosphatase↗