PubMed Health⌕ Search

Biomedical subjects

P J Campbell

Publications and source records attributed to P J Campbell.

At least 19 recordsLinked to original sources
PubMed2006

Randomized clinical trial to investigate the effectiveness of teflubenzuron for treating sea lice on Atlantic salmon.

A double-blind, randomized control clinical trial was performed to investigate the effectiveness of teflubenzuron in controlling sea lice Lepeophtheirus salmonis on farmed Atlantic salmon Salmo salar. A total of 40 sea cages from 3 commercial cage sites in Atlantic Canada were used in this Good Clinical Practice (GCP) trial. The teflubenzuron was administered in the feed at a dosage of 10 mg kg(-1) biomass d(-1) for 7 d. Medicated and control cages were matched by site, cage size, and pre-treatment mean lice counts using cages as the unit of concern. Post-treatment lice counts and staging of developmental stages were performed at 1 and 2 wk after the end of treatment. Chalimus stages in medicated cages were significantly lower than in control cages at 1 wk (79% reduction in mean lice counts, p < 0.001), and at 2 wk (53% reduction, p < 0.001). Mobile (pre-adult and adult) stages were also significantly reduced in medicated cages at 1 wk (69% reduction, p < 0.01), and at 2 wk (40% reduction, p < 0.01) post-treatment, respectively. Teflubenzuron was proven effective for reducing lice burdens on salmon despite the low parasite levels experienced during the trial and the recruitment of lice from the untreated cages. The use of cage as the unit of concern was an important design component of this trial.

Administration, Oral↗
PubMed2006

Historical control clinical trial to assess the effectiveness of teflubenzuron for treating sea lice on Atlantic salmon.

A historical control clinical trial was performed to assess the effectiveness of teflubenzuron in controlling sea lice Lepeoptheirus salmonis burdens on farmed Atlantic salmon Salmo salar over time. The study site comprised 9 sea cages, all of which were treated. The teflubenzuron was administered in the feed, at a dosage of 10 mg kg(-1) biomass d(-1), over a treatment period of 7 d. At 1 wk post-treatment, sea lice chalimus and mobile stages were reduced by 92 and 74% (both p < 0.001), respectively. At 2 wk post-treatment, chalimus stages were reduced by 41% and mobile stages 61% (both p < 0.001) compared to pre-treatment levels. At 3 wk post-treatment, chalimus stages were still 36% (p < 0.001) lower than pre-treatment levels, but mobile stages had increased to above pre-treatment levels. Our results show that the effects of teflubenzuron are limited to a 3 wk duration, but that with appropriate management, farms could benefit from these reduced lice burdens for longer periods.

Administration, Oral↗
PubMed2001

Replacement of fish oil with rapeseed oil in diets of Atlantic salmon (Salmo salar) affects tissue lipid compositions and hepatocyte fatty acid metabolism.

Duplicate groups of Atlantic salmon post-smolts were fed five practical-type diets in which the added lipid was 100% fish oil [FO; 0% rapeseed oil (0% RO)], 90% FO + 10% RO (10% RO), 75% FO + 25% RO (25% RO), 50% FO + 50% RO (50% RO) or 100% RO, for a period of 17 wk. There were no effects of diet on growth rate or feed conversion nor were any histopathological lesions found in liver, heart, muscle or kidney. The greatest accumulation of muscle lipid was in fish fed 0% RO, which corresponded to significantly lower muscle protein in this group. The highest lipid levels in liver were found in fish fed 100% RO. Fatty acid compositions of muscle lipid correlated with RO inclusion in that the proportions of 18:1(n-9), 18:2(n-6) and 18:3(n-3) all increased with increasing dietary RO (r = 0.98-1.00, P < 0.013). The concentrations of eicosapentaenoic acid [20:5(n-3)] and docosahexaenoic acid [22:6(n-3)] in muscle lipid were significantly reduced (P < 0.05), along with total saturated fatty acids, with increasing dietary RO. Diet-induced changes in liver fatty acid compositions were broadly similar to those in muscle. Hepatic fatty acid desaturation and elongation activities, measured using [1-(14)C] 18:3(n-3), were increased with increasing dietary RO. Limited supplies of marine fish oils require that substitutes be found if growth in aquaculture is to be maintained such that fish health and product quality are not compromised. Thus, RO can be used successfully as a substitute for fish oil in the culture of Atlantic salmon in sea water although at levels of RO >50% of dietary lipid, substantial reductions occur in muscle 20:5(n-3), 22:6(n-3) and the (n-3)/(n-6) polyunsaturated fatty acid (PUFA) ratio, which will result in reduced availability of the (n-3) highly unsaturated fatty acids that are beneficial for human health.

Animals↗
PubMed1999

HEPTEST: a suitable method for monitoring heparin during pregnancy.

Methods of monitoring heparin in pregnancy are problematic. The aim of this study was to assess the plasma HEPTEST as a rapid and reliable test for heparin monitoring in pregnancy. HEPTEST, activated partial thromboplastin time (APTT) and chromogenic anti-Xa assays were performed on individual heparin-spiked plasma samples from two groups: normal non-pregnant women (n = 6) and normal pregnant women during the third trimester (n = 6). Heparin activity curves were established in plasma from both groups for low (< 0.3 IU/ml), intermediate (0.3-0.7 IU/ml) and high (> 0.7 IU/ml) heparin concentrations and validated by comparison with the anti-Xa chromogenic assay. Both the APTT and HEPTEST demonstrated good correlation with anti-Xa levels across all heparin concentrations in both plasma groups (r range = 0.879-0.945). In comparison with the APTT, the HEPTEST showed better correlation with anti-Xa levels at low concentrations of heparin (r values 0.933 vs. 0.772, respectively). For both the APTT and HEPTEST there were significant differences between the clotting times in pregnant and non-pregnant plasma at a number of heparin concentrations. This data supports the plasma HEPTEST as an acceptable alternative to the chromogenic anti-Xa assay for monitoring heparin thromboprophylaxis in pregnancy.

Adult↗
PubMed1998

Continuous and intermittent infusion of coagulation factor concentrates in patients undergoing surgery: a single centre Australian experience.

BACKGROUND: Haemophilia patients require large doses of coagulation factor concentrates to optimise haemostasis at the time of surgery. The superior pharmacokinetic profile of continuous infusion over intermittent bolus administration may be more advantageous. AIMS: We report our experience using coagulation factor concentrates delivered by continuous infusion in patients undergoing surgery. METHODS: A retrospective case notes review of all patients treated by continuous infusion at Royal Prince Alfred Hospital (RPAH) over a two year period and a comparison of two cohorts of patients undergoing orthopaedic surgery using either continuous infusion or bolus factor VIII (FVIII) replacement therapy. Patients received a pre-operative bolus of factor concentrate (AHF, Immunine or Recombinate) followed by a continuous infusion calculated according to weight, clearance and target plasma concentration. RESULTS: Twenty-one (19 M, two F) with haemophilia or von Willebrand's disease underwent 26 surgical procedures between July 1995 and July 1997. The mean total consumption of concentrate per patient was 36,676 units (range 6750-82,000) infused over a mean period of 7.6 days (range one-16). One patient experienced minor surgical bleeding on treatment and one patient developed severe bleeding into the replaced joint off infusion requiring additional boluses of treatment. In a separate analysis, ten of these patients who underwent major orthopaedic surgery were compared to a historic cohort (n = 8) of patients who received bolus injections for similar types of operations. CONCLUSIONS: Coagulation factor concentrates delivered by continuous infusion have major clinical and economic advantages in the surgical management of patients with haemophilia.

Adult↗
PubMed1998

Randomised controlled trial of cisapride in feed intolerance in preterm infants.

AIM: To assess the efficacy of cisapride in reducing the time required to establish enteral feeds in preterm infants. METHODS: A randomised, double blind, placebo controlled trial was conducted of 34 infants of < or = 32 weeks of gestation, assigned to receive either cisapride 0.2 mg/kg/dose four times daily (n = 18) or placebo (n = 16). RESULTS: The time taken by the babies to tolerate full enteral feeds was not significantly different between the groups (median 9.5 days vs 10 days). There was a significantly lower incidence of large gastric residuals and regurgitation in the treated group compared with the placebo group. The number of episodes of large gastric residuals per infant was also significantly less. No adverse effects were noted. CONCLUSION: The routine use of cisapride in preterm infants cannot be recommended to decrease the time to establish enteral feeds. Its use may be justified for clinically significant gastric stasis or regurgitation.

Cisapride↗
PubMed1997

Splenic regrowth in sickle cell anaemia following hypertransfusion.

We describe five adult patients with sickle cell anaemia (SS) who developed clinical, radiological and histological evidence of splenic regrowth while receiving regular blood transfusions. Five patients, all homozygous SS, range 23-34 years, were commenced on hypertransfusion therapy. Three patients were transfused because of severe recurrent vaso-occlusive crises, one for chronic sickle lung and one in an attempt to prevent deterioration of renal function. The mean duration of hypertransfusion prior to documentation of splenic regrowth was 52 months (range 12-97 months). Two patients developed significant hypersplenism. One patient had clinically-apparent splenomegaly and four patients had splenomegaly documented on ultrasound. Splenic regrowth in hypertransfused adults with sickle cell anaemia is not infrequent and may have important clinical implications.

Adult↗
PubMed1997

Human immunodeficiency virus seroprevalence and risk behaviors in patients attending sexually transmitted disease clinics in Alberta.

OBJECTIVE: To investigate the dissemination of human immunodeficiency virus (HIV) and hepatitis C infection in association with sexually transmitted diseases (STDs), sexual practices, and injection drug use. All eligible men and women attending two STD clinics in Alberta, Canada, from May 1994 to May 1995 were studied. STUDY DESIGN: Anonymous, unlinked serosurveys were performed using leftover sera drawn for routine syphilis, hepatitis B, or HIV testing. Self-administered questionnaires collected a wide range of data: demographic, sexual behaviors, condom use, STD history, the exchange of drugs or money for sex, and drug and alcohol use. RESULTS: HIV seroprevalence in the overall sample group (n = 6,668) was 1.5%. Univariate analysis showed significant relationships for age between 30 years and 49 years, men having sex with men, injection drug use regardless of sexual orientation, history of STD, anal sex, and exchanging money or drugs for sex. At the multivariate level, only men having sex with men, injection drug use, and age more than 30 years remained predictive of HIV infection. The prevalence of hepatitis C was 3.4% with significant associations being injection drug use and exchanging money or drugs for sex. CONCLUSION: The behavioral associations between sex practices, injection drug use, and HIV and hepatitis C seroprevalence warrant ongoing investigation. Continuing prevention programs targeted at safer sex practices (particularly for men having sex with men) and the use of clean needles are needed.

Adolescent↗
PubMed1997

Hyperdynamic therapy: the nurse's role in the treatment of cerebral vasospasm.

The onset of subtle diffuse ischemic neurological deficits often associated with cerebral vasospasm is a major cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage. The exact etiology of cerebral vasospasm is unclear. Increasing intravascular volume, decreasing blood viscosity and inducing hypertension may help prevent or diminish neurological deficits from cerebral vasospasm by improving cerebral blood flow. An intensive multidisciplinary approach is necessary with the role of the neuroscience nurse being pivotal. An understanding of the subtle neurological changes suggestive of cerebral vasospasm and its effects leads to early recognition, and allows for rapid institution of therapy.

Adult↗
PubMed1997

Decrease in CD4 lymphocyte counts with rest; implications for the monitoring of HIV infection.

Measurement of the CD4 lymphocyte count is widely used as a prognostic marker and guide for the institution of antiretroviral therapy in patients infected with HIV (human immunodeficiency virus). CD4 counts are known to fluctuate with strenuous physical activity and diurnal variation but there is no information on the effects of rest or normal daily activity. We investigated the effects of rest on the absolute CD4 lymphocyte count in 20 healthy laboratory workers. Blood samples were obtained in 20 subjects upon arrival in the laboratory (CD4 0), following 30 and 60 min rest (CD4 30 and CD4 60 respectively) and 8 h into a normal working day (CD4 8). A significant decrease in the CD4 lymphocyte count was observed following 60 min rest; mean CD4 count at 0 min 1060 x 10(6)/L, mean CD4 count at 60 min 660 x 10(6)/L (P = 0.0017). These results demonstrate a significant effect of rest on CD4 lymphocyte counts in healthy volunteers. This biological variation may be important in HIV-infected patients and needs to be addressed by further studies.

Activities of Daily Living↗
PubMed1995

A practical guide to intensive insulin therapy.

In a landmark study, the Diabetes Control and Complications Trial proved that intensive insulin therapy (IIT) reduced the incidence and severity of the microvascular complications of insulin-dependent diabetes mellitus. Retinopathy, nephropathy, and neuropathy were all improved by IIT. The trial was conducted by endocrinologists experienced in the management of IIT. However, only a small minority of patients with diabetes are cared for by endocrinologists; the vast majority receive their care from primary care physicians. In this article, the authors describe the practical aspects of IIT for those physicians unfamiliar with IIT but who want to offer the benefits of this therapy to patients with diabetes. The authors define suitable candidates for IIT, describe the initiation and management of IIT, and emphasize the potential complications of this therapy. Severe hypoglycemia is the major risk of ITT, and caution must be used to reduce the incidence of this dangerous complication.

Diabetes Mellitus, Type 1↗
PubMed1995

Immunogenicity of oral poliovirus vaccine administered in mass campaigns versus routine immunization programmes.

Reported are the results of a study to investigate the immunogenicity of oral poliovirus vaccine (OPV) when administered in mass campaigns compared with that following routine immunization programmes. For this purpose, paired sera were collected from a cohort of children before and after a mass vaccination with OPV in Morocco in 1987. Serum samples and information on vaccination status and other confounding factors that could influence antibody responses to OPV were collected. Neutralizing antibody titres to poliovirus types 1, 2 and 3 were determined using a standardized assay. OPV doses administered exclusively during the mass campaign were consistently associated with higher type-specific seroprevalence rates than the same number of doses administered in the routine programme. These findings could not be attributed to differences in confounding factors. Enhanced secondary spread of vaccine virus may have occurred but could not be demonstrated because of limitations in the study design. Mass campaigns appear to be highly effective in raising the dose-related poliovirus type-specific immunity of the population above that achieved by the routine immunization programme. Our findings support the continued use of mass campaigns as an adjunct to routine programmes in order to both enhance and catalyse current efforts to achieve the global eradication of poliomyelitis by the year 2000.

Antibodies, Viral↗
PubMed1994

Fuel and energy metabolism in fasting humans.

Fuel and energy homeostasis was examined in six male volunteers during a 60-h fast by using a combination of isotopic tracer techniques ([3-3H]glucose, [2H5]glycerol, [1-14C]palmitate, and L-[1-13C]leucine) and indirect calorimetry. Plasma glucose concentration and hepatic glucose production decreased by 30% with fasting (5.2 +/- 0.1 to 3.8 +/- 0.2 mmol/L and 11.8 +/- 0.5 to 8.2 +/- 0.6 mumol.kg-1.min-1, respectively, both P < 0.001) and glucose oxidation declined approximately 85% (P < 0.01). Lipolysis and primary (intraadipocyte) free fatty acid (FFA) reesterification increased 2.5-fold (1.7 +/- 0.2 to 4.2 +/- 0.2 mumol.kg-1.min-1 and 1.5 +/- 0.4 to 4.2 +/- 0.8 mumol.kg-1.min-1, respectively, both P < 0.05). This provided substrate for the increase in fat oxidation (from 2.7 +/- 0.3 to 4.3 +/- 0.1 mumol.kg-1.min-1, P < 0.01), which contributed approximately 75% of resting energy requirements after the 60-h fast and increased the supply of glycerol for gluconeogenesis. Proteolysis and protein oxidation increased approximately 50% during fasting (P < 0.01 and P < 0.05, respectively). We conclude that the increase in FFA reesterification with fasting modulates FFA availability for oxidation and maximizes release of glycerol from triglyceride for gluconeogenesis.

Adipose Tissue↗
PubMed1994

Fat metabolism in human obesity.

Excessive fat turnover and oxidation might cause the insulin resistance of carbohydrate metabolism in obese humans. We studied the response of free fatty acid (FFA) metabolism in lean and obese volunteers to sequential insulin infusions of 4, 8, 25, and 400 mU.m-2.min-1. The insulin dose-response curves for suppression of FFA concentration, FFA turnover ([1-14C]palmitate), and lipolysis ([2H5]glycerol) were shifted to the right in the obese subjects (insulin concentrations that produced a half-maximal response, lean vs. obese: 103 +/- 21 vs. 273 +/- 41, 96 +/- 11 vs. 264 +/- 44, and 101 +/- 23 vs. 266 +/- 44 pM, all P < 0.05), consistent with insulin resistance of FFA metabolism in obesity. After the overnight fast, FFA turnover per fat mass was decreased in obese subjects (37 +/- 4 vs. 20 +/- 3 mumol.kg fat mass-1.min-1, P < 0.01) as the result of suppression of lipolysis by the hyperinsulinemia of obesity and an increased fractional reesterification of FFA before leaving the adipocyte (primary FFA reesterification; 0.14 +/- 0.03 vs. 0.35 +/- 0.06, P < 0.05). Nevertheless, FFA turnover per fat-free mass (FFM) was also greater in the obese volunteers (8.5 +/- 0.7 vs. 11.0 +/- 1.0 mumol.kg FFM-1.min-1, P < 0.05) but only as the result of increased reesterification of intravascular FFA (secondary reesterification; 1.8 +/- 0.5 vs. 4.8 +/- 1.1 mumol.kg FFM-1.min-1, P < 0.01), since FFA oxidation was the same in the two groups throughout the insulin dose-response curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Differential effects of hyperglycemia and hyperinsulinemia on leucine rate of appearance in normal humans.

To determine the independent effects of insulin and glucose on the rate of appearance of leucine in humans, five normal volunteers were studied using a pancreatic clamp with sequential insulin infusions of 1.8, 3.6 and 7.2 pmol kg/min-1. On each of three separate occasions, the plasma glucose level was maintained at 5.0, 9.4 or 14 mM. The rate of appearance of leucine was similar at each insulin infusion rate regardless of the ambient glucose concentration or the glucose infusion rate. These studies demonstrate that during insulin and glucose infusion, insulin, but neither the plasma glucose concentration nor the rate of glucose utilization, primarily regulates leucine flux (a reflection of endogenous whole body proteolysis) in normal humans.

Adult↗
PubMed1993

Regulation of free fatty acid metabolism by glucagon.

Glucagon may regulate FFA metabolism in vivo. To test this hypothesis, six healthy male volunteers were infused with somatostatin, to inhibit endogenous hormone secretion, and insulin, glucagon, and GH to replace endogenous secretion of these hormones. In the hypoglucagonemia experiments, the glucagon infusion was omitted, and in the hyperglucagonemic experiments glucagon was infused at 1.3 ng/kg.min, to produce physiological hyperglucagonemia. In two sets of control experiments, glucagon was infused at 0.65 ng/kg.min, in order to maintain peripheral euglucagonemia, and the plasma glucose concentrations were clamped at the levels observed in either the hypo- or hyperglucagonemic experiments. Rates of FFA and glycerol (an index of lipolysis) appearance (Ra) were estimated with the isotope dilution method using [1-14C]palmitate and [2H5] glycerol. Plasma glucagon concentrations decreased during the hypoglucagonemic experiments (85 +/- 12 vs. 123 +/- 22 ng/L, P < 0.05) and increased during the hyperglucagonemic experiments (186 +/- 20 vs. 125 +/- 15 ng/L, P < 0.05), whereas other hormone concentrations remained the same. Hypoglucagonemia resulted in equivalent suppression of FFA Ra (3.7 +/- 0.2 vs. 5.9 vs. 0.3 mumol/kg.min, P < 0.01) and glycerol Ra (1.2 +/- 0.2 vs. 2.2 +/- 0.5 mumol/kg.min, P < 0.05). Similarly, hyperglucagonemia resulted in equivalent stimulation of FFA Ra (5.2 +/- 0.4 vs. 3.7 +/- 0.3 mumol/kg.min, P < 0.05) and glycerol Ra (1.5 +/- 0.3 vs. 1.1 +/- 0.1 mumol/kg.min, P < 0.05). These results indicate that glucagon has a physiological role in the regulation of FFA metabolism in vivo.

Adult↗