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Biomedical subjects

L Ferguson

Publications and source records attributed to L Ferguson.

At least 19 recordsLinked to original sources
PubMed2000

Ascaris suum, an intestinal parasite, produces morphine.

The parasitic worm Ascaris suum contains the opiate alkaloid morphine as determined by HPLC coupled to electrochemical detection and by gas chromatography/mass spectrometry. The level of this material is 1168 +/- 278 ng/g worm wet weight. Furthermore, Ascaris maintained for 5 days contained a significant amount of morphine, as did their medium, demonstrating their ability to synthesize the opiate alkaloid. To determine whether the morphine was active, we exposed human monocytes to the material, and they immediately released nitric oxide in a naloxone-reversible manner. The anatomic distribution of morphine immunoreactivity reveals that the material is in the subcuticle layers and in the animals' nerve chords. Furthermore, as determined by RT-PCR, Ascaris does not express the transcript of the neuronal mu receptor. Failure to demonstrate the expression of this opioid receptor, as well as the morphine-like tissue localization in Ascaris, suggests that the endogenous morphine is intended for secretion into the microenvironment.

Animals↗
PubMed2000

The potential to use PspA and other pneumococcal proteins to elicit protection against pneumococcal infection.

Pneumococcal proteins, alone, in combination with each other, or in combination with capsular polysaccharide-protein conjugates may be useful pneumococcal vaccine components. Four proteins with a potential for use in vaccines are PspA, pneumolysin, PsaA, and PspC. In a mouse model of carriage, PsaA and PspC were the most efficacious vaccine proteins. Of these, PsaA was the best at eliciting protection against carriage. However, a combination of PspA and pneumolysin may elicit stronger immunity to pulmonary infection and possibly sepsis than either protein alone. Recently, a phase one trial of a recombinant family 1 PspA was completed in man. PspA was observed to be safe and immunogenic. Injection of 0.1 ml of immune serum diluted to 1/400 was able to protect mice from fatal infection with S. pneumoniae. Under these conditions, pre-immune serum was not protective. The immune human serum protected mice from infections with pneumococci expressing either of the major PspA families (1 and 2) and both of the pneumococcal capsular types tested: 3 and 6.

Adult↗
PubMed1998

Randomized trial of pamidronate in patients with thyroid cancer: bone density is not reduced by suppressive doses of thyroxine, but is increased by cyclic intravenous pamidronate.

Patients taking suppressive doses of T4 are thought to have accelerated bone loss and increased risk of osteoporosis. We therefore randomize 55 patients taking suppressive doses of T4 to treatment with pamidronate (APD) 30 mg i.v. every 3 months for 2 yr (APD/T4), or placebo (placebo/T4). Patients had measurements of bone mineral density (BMD) of the spine, hip, radius, and total body every 6 months for 2 yr. There was no significant bone loss at any site in the placebo/T4 group. Ninety five percent confidence intervals excluded a rate of bone loss > 0.89%/yr for the spine and > 0.31%/yr at the total hip. When men were excluded from the analysis, there still was no significant bone loss for the placebo/T4 group, and confidence intervals did not change. The APD/T4 group showed increases in spine (4.3%, P = 0.0001), total hip (1.4%, P < 0.05), and trochanteric (3.0%, P = 0.0001) BMDs. In conclusion, premenopausal women and men on suppressive therapy with T4 do not lose bone rapidly, and are not at increased risk of developing osteoporosis. A regimen of 30 mg APD given every 3 months for 2 yr causes significant suppression of bone resorption and increases in BMD, and may be an acceptable alternative treatment for osteoporosis in patients who cannot tolerate oral bisphosphonates.

Adult↗
PubMed1998

Early changes in biochemical markers of bone turnover predict the long-term response to alendronate therapy in representative elderly women: a randomized clinical trial.

Although the antiresorptive agent alendronate has been shown to increase bone mineral density (BMD) at the hip and spine and decrease the incidence of osteoporotic fractures in older women, few data are available regarding early prediction of long-term response to therapy, particularly with regard to increases in hip BMD. Examining short-term changes in biochemical markers incorporates physiologic response with therapeutic compliance and should provide useful prognostic information for patients. The objective of this study was to examine whether early changes in biochemical markers of bone turnover predict long-term changes in hip BMD in elderly women. The study was a double-blind, placebo-controlled, randomized clinical trial which took place in a community-based academic hospital. One hundred and twenty community-dwelling, ambulatory women 65 years of age and older participated in the study. Intervention consisted of alendronate versus placebo for 2.5 years. All patients received appropriate calcium and vitamin D supplementation. The principal outcome measures included BMD of the hip (total hip, femoral neck, trochanter, and intertrochanter), spine (posteroanterior [PA] and lateral), total body, and radius. Biochemical markers of bone resorption included urinary N-telopeptide cross-linked collagen type I and free deoxypyridinoline; markers of bone formation included serum osteocalcin and bone-specific alkaline phosphatase. Long-term alendronate therapy was associated with increased BMD at the total hip (4.0%), femoral neck (3.1%), trochanter (5.5%), intertrochanter (3.8%), PA spine (7.8%), lateral spine (10.6%), total body (2.2%), and one-third distal radius (1.3%) in elderly women (all p < 0.01). In the placebo group, bone density increased 1.9-2.1% at the spine (p < 0.05) and remained stable at all other sites. At 6 months, there were significant decreases in all markers of bone turnover (-10% to -53%, p < 0.01) in women on alendronate. The changes in urinary cross-linked collagen at 6 months correlated with long-term bone density changes at the hip (r = -0.35, p < 0.01), trochanter (r = -0.36, p < 0.01), PA spine (r = -0.41, p < 0.01), and total body (r = -0.34, p < 0.05). At 6 months, patients with the greatest drop in urinary cross-linked collagen (65% or more) demonstrated the greatest gains in total hip, trochanteric, and vertebral bone density (all p < 0.05). A 30% decrease in urinary cross-linked collagen at 6 months predicted a bone density increase of 2.8-4.1% for the hip regions and 5.8-6.9% for the spine views at the 2.5-year time point (p < 0.05). There were no substantive associations between changes in biochemical markers and bone density in the placebo group. Alendronate therapy was associated with significant long-term gains in BMD at all clinically relevant sites, including the hip, in elderly women. Moreover, these improvements were associated with early decreases in biochemical markers of bone turnover. Early dynamic decreases in urinary cross-linked collagen can be used to monitor and predict long-term response to bisphosphonate therapy in elderly women. Future studies are needed to determine if early assessment improves long-term patient compliance or uncovers poor compliance, thereby aiding the physician in maximizing the benefits of therapy.

Aged↗
PubMed1997

Efficacy of moxidectin, ivermectin and albendazole oral drenches for suppression of periparturient rise in ewe worm egg output and reduction of anthelmintic treatment for lambs.

Sixty multiparous crossbred ewes which had lambed within three days in the first week of April 1996, were divided into four groups. Each group consisted of 15 ewes plus 12 pairs of twins and three single lambs. Group 1 was left untreated, group 2 was treated with albendazole 2.5 per cent drench, group 3 received moxidectin 0.1 per cent drench and group 4 received ivermectin 0.08 per cent drench. The ewes in each group were dosed with their anthelmintic on April 4 (day 0) before being turned out to separate equal-sized paddocks within the same field on the following morning. The field had been used for grazing sheep annually for many years and was considered to be contaminated with infective larvae of the common gastrointestinal nematodes infecting sheep in the region. Faecal samples were collected every two weeks from the ewes and lambs until July 25 (day 112). The lambs in each group were dosed with the anthelmintic used for their dams on day 42, and the dose was repeated when more than 50 per cent of the lambs in any group had a faecal egg count of more than 200 eggs per gram (epg). The total faecal egg output of the treated ewes over days 14 to 70, compared with that of the untreated control group, was reduced by 78.9 per cent by the moxidectin drench, by 47.6 per cent by ivermectin, and by 21.5 per cent by albendazole. The lambs in the groups treated with moxidectin and ivermectin required only one treatment on day 42 before reaching finishing weight; those in the albendazole-treated group were treated twice and the control group once. The faecal egg outputs of the lambs from day 42 until the end of the experiment on day 112 were reduced by 75 per cent by the moxidectin drench, by 48.5 per cent by ivermectin, and by 9 per cent by albendazole. There were no significant differences between the rates of weight change of either ewes or lambs in any of the groups.

Albendazole↗
PubMed1997

Diurnal variation of bone mineral turnover in elderly men and women.

The diurnal variation of markers of bone mineral metabolism have been documented in pre- and early postmenopausal women. Such rhythms have clinical implications for timing of sample collection and assessment of therapeutic intervention. To examine the diurnal variation of bone turnover in the elderly, we examined markers of bone formation [serum osteocalcin (OC) and bone-specific alkaline phosphatase (B-ALP)]; a marker of bone resorption (urinary N-telopeptide cross-linked collagen type 1 [NTX]); and serum calcium and parathyroid hormone (PTH) over 24 hours. Subjects were healthy community-dwelling elderly who were on no medications known to significantly alter bone mineral metabolism. Subjects included 14 women [74 +/- 6 years (mean +/- SD)] and 14 men (80 +/- 5 years). Over the 24-hour sampling period, mean serum OC, B-ALP, and calcium values were similar in elderly men and women. However, mean serum PTH was significantly higher in elderly men compared with women (P < 0.05). The magnitude of the diurnal variation of urinary NTX was significantly higher in women compared with men (P < 0.05). There was a significant diurnal variation for serum OC, B-ALP, calcium, PTH, and urinary NTX in both elderly men and women. The magnitude of the diurnal variation was approximately 10-20% of mean value for OC and B-ALP, 30% for PTH, and up to 40% for urinary NTX. We conclude that there is significant diurnal variation in the markers of bone mineral metabolism for elderly men and women. The peak value, which on average would be 20% higher than the mean value for urinary NTX, highlights the importance of the timing of sample collection for appropriate interpretation of therapeutic response. In addition, gender-related differences, including relatively higher levels of serum PTH and lower levels of urinary NTX in elderly men, may help explain differences in rates of bone loss in this age group.

Age Factors↗
PubMed1997

Modulation of the potency of promutagens and direct acting mutagens in bacteria by inhibitors of the multidrug resistance mechanism.

Multiple drug resistance (MDR) mechanisms are known to limit the effectiveness of some cancer chemotherapies, probably through enhancing P-glycoprotein-mediated drug efflux from mammalian cells. Similar mechanisms appear to act in other organisms, including bacteria, and may affect not only the toxicity but also the mutagenicity of certain chemicals. At least in some experimental situations, MDR can be overcome through concomitant treatment of the cells with various types of inhibitors. Two MDR inhibitors, verapamil, a calcium channel blocker, and trifluoperazine, a calmodulin inhibitor, were assayed for their ability to modulate the potency of nine mutagens with varying mechanisms of action in various Salmonella typhimurium his- strains. Neither verapamil nor trifluoperazine affected the direct mutagenicity of sodium dichromate and 2-methoxy-6-chloro-9[3-(2-chloroethyl)amino-propyl-amino] dihydrochloride (ICR 191) or the S9-mediated mutagenicity of benzo[a]pyrene and 2-amino-3,4-dimethyl-amidazo[4,5-f]quinoline (MeIQ). Both modulators enhanced the direct mutagenicity of doxorubicin. Moreover, trifluoperazine sharply increased the S9-mediated mutagenicity of cyclophosphamide and 2-aminofluorene, while it consistently decreased the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). The contrasting effect towards the aromatic amine 2-aminofluorene and the heterocyclic amine Trp-P-2, representative of important chemical families responsible for the bacterial mutagenicity of cigarette smoke, may explain the observed lack of influence of trifluoperazine on the mutagenicity of a cigarette smoke condensate. These observations extend the known range of chemical types whose mutagenicity can be modulated by inhibitors of MDR and suggest that there may be value in adding MDR inhibitors, especially trifluoperazine, to optimize the detection of mutagenicity by certain types of chemicals in the Salmonella/mammalian microsome mutagenicity test.

Acridines↗
PubMed1996

Mechanisms and targets involved in maternal and paternal age effects on numerical aneuploidy.

Trisomy in the human appears to be predominantly associated with maternal age. The maternal-age effect, however, shows considerable variability across affected chromosomes. Chromosome-specific variation has been reported in the shapes of the maternal-age-effect curves, including very small effects for the large chromosomes (groups A and B), linear increases (chromosome 16), and exponential increases (chromosome 21). There is also variation among chromosomes in whether the segregation errors occur predominantly at maternal meiosis I, meiosis II, and/or postfertilization mitotic divisions. There is also limited epidemiological evidence for a paternal-age effect, which was recently supported by the findings of age-related increases in sperm aneuploidy using fluorescence in situ hybridization methods. The paternal-age effect is considerably smaller than the maternal and is more likely to involve meiotic II errors of the sex chromosomes, whereas the maternal-age effect is more likely to arise from meiotic I errors producing autosomal trisomies. These and other differences suggest that constitutional aneuploidy arises by multiple mechanisms that may affect (1) the nature and timing of an initiating lesion affecting the oocyte or sperm; (2) the cellular physiology of the time of the nondisjunction event at meiosis I, II, or postfertilization; and (3) the selection against specific chromosomal aneuploidies during embryonic development. Multidisciplinary research is needed to understand the maternal and paternal-age effects on aneuploidy, to (1) identify and characterize the genes that control meiosis, recombination, and segregation; (2) identify the micro-environmental factors around the oocyte and mole germ cells that are involved in the age effects; (3) develop a laboratory animal model for the age effects; (4) characterize the role of genetics, physiology, and environmental toxicology for the paternal-age effects; and (5) identify cohorts of men and women of differing ages who have been exposed to high doses of candidate aneugens and conduct epidemiological investigations of aneuploidies transmitted to their offspring.

Adult↗
PubMed1994

Casemix issues for nursing.

The diagnosis-related groups (DRGs) patient classification system provides information about the type and volume of acute inpatients treated, as well as the length of stay and cost of treatment. Nurses have been involved in casemix development in Australia, providing advice to government departments on nursing issues; researching the relative cost of nursing patients in one diagnosis-related group compared with another; budgeting nursing resources for casemix treated; and using casemix information to change practices to achieve more efficient use of resources and maintain quality of care. Casemix information allows nurses to contribute to the management of clinical services in partnership with other clinicians and managers.

Australia↗