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Biomedical subjects

A Crowe

Publications and source records attributed to A Crowe.

At least 19 recordsLinked to original sources
PubMed2006

Use of icodextrin 4% solution in the prevention of adhesion formation following general surgery: from the multicentre ARIEL Registry.

INTRODUCTION: Intra-abdominal adhesions occur in many patients following major abdominal surgery and represent a serious burden to patients and healthcare providers. The multicentre ARIEL (Adept Registry for Clinical Evaluation) Registry was established to gather clinical experiences in the use of icodextrin 4% solution, an approved adhesion-reduction agent, during routine general surgery. PATIENTS AND METHODS: General surgeons from five European countries completed anonymised data collection forms for patients undergoing laparotomy or laparoscopy. Surgeons recorded patient demographics, use of icodextrin 4% solution and adverse events, and made subjective assessments of ease of use and patient acceptability with the agent. RESULTS: The general surgery registry included 1738 patients (1469 laparotomies, 269 laparoscopies). Leakage of fluid from the surgical site did not appear to be affected by icodextrin 4% solution and was classified as 'normal' or 'less than normal' in most patients (laparotomies 86%, laparoscopies 88%). Overall, satisfaction with ease of use was rated as 'good' or 'excellent' by the majority of surgeons (laparotomies 77%, laparoscopies 86%). Patient acceptability was also good, with ratings of 'as expected' or 'less than expected' in most cases for both abdominal distension (laparotomies 90%, laparoscopies 91%) and abdominal discomfort (laparotomies 91%, laparoscopies 93%). Adverse events occurred in 30.6% of laparotomy patients and 16.7% of laparoscopy patients; the most common events were septic/infective events (4.2% and 3.4% in the laparotomy and laparoscopy groups, respectively). Anastomotic wound-healing problems were reported in 7.6% of patients in the subset of laparoscopy patients undergoing anastomotic procedures (n = 66). DISCUSSION: Volumes of icodextrin 4% solution used as an irrigant and instillate were in line with recommendations. Surgeons considered the agent to be easy to use and acceptable to patients. The reported frequencies of adverse events were in line with those published in the literature for surgical procedures, supporting the good safety profile of this agent. CONCLUSIONS: Icodextrin 4% solution can be used in a wide range of surgical procedures. In combination with good surgical technique, it may play an important role in adhesion reduction.

Glucans↗
PubMed2001

Differences in gait parameters at a preferred walking speed in healthy subjects due to age, height and body weight.

The objective of our cross-sectional study was to investigate the changes associated with age and gender in walking speed, stride length and cadence of healthy women and men over the adult age range, and establish the effects of anthropometric indices such as height and body weight. We examined 118 women and 121 men (age range, 19-90 years). Subjects walked at their preferred speed over a 12-meter walkway crossing two Kistler force plates: cadence was calculated from heel strike times recorded from the Kistler force plates; walking speed was measured using an infrared reflecting system; and stride length was calculated from the walking speed and cadence. Older healthy subjects had lower values for walking speed and stride length than younger subjects. While there is little difference in the percentage reduction between women and men over the adult age range. the absolute values for walking speed are lower in women than men at all ages. In women, the percentage of explained variance for decline in walking speed was 30%, and for decline in stride length 400%. If body weight was also taken into account, the percentage of explained variance for walking speed was 37%, and for stride length 59%. A similar calculation for men yields 34% for decline in walking speed, and 42% for decline in stride length. Cadence was not associated with age, height and body weight. The standard errors for the estimates of walking speed in both women and men, respectively, are reduced by 8% and 3% using the multiple regression technique. The corresponding standard errors for stride length were reduced by, respectively, 19% and 13% if height in either sexes, or height and body weight in women, were taken into account. In conclusion, preferred walking speed and stride length decline with age in healthy people. Lower values found in old healthy subjects partly contributed to the difference in height and body weight between old and young subjects. Cadence was not correlated with age, height and body weight.

Adult↗
PubMed2000

Relationships between physical performance measures, age, height and body weight in healthy adults.

OBJECTIVE: we measured muscle strength and functional mobility in healthy men and women over the adult age range to investigate the changes with age and sex, and to establish the effects of the anthropometric indices height and weight. DESIGN: cross-sectional study. SUBJECTS AND METHODS: we recruited 74 healthy women (mean age 49.0, range 20-90) and 81 healthy men (mean age 51.6, range 20-90). We measured maximum isometric knee extension strength, handgrip strength and explosive leg extensor power. We assessed functional mobility quantitatively with the timed 'get up and go' test and the modified Cooper test. RESULTS: older subjects had lower values for muscle strength and muscle power than young subjects. Times for the timed 'get up and go' test were longer and distances in the modified Cooper test shorter. At about the age of 55, women showed an acceleration in the decline of isometric knee extension strength and handgrip strength (between 20 and 55 years, knee strength decreased by 10.3% and handgrip strength decreased by 8.2%, between 55 and 80 years the decreases were 40.2% and 28% respectively). Men showed a more gradual declines over the adult age range, with decreases in knee and handgrip strength of 24% and 19.6% between 20 and 55 years, and 23% and 17.4% between 55 and 80 years. The age-related decline is partly associated with differences in height and body weight. Women had higher correlations between muscle strength and functional mobility tests than men. CONCLUSIONS: muscle strength and functional mobility decline with age in healthy people; in women we observed an accelerated decrement in muscle strength above the age of 55. Lower values in healthy old subjects are partly associated with differences in height and body weight.

Adult↗
PubMed1999

Absorption and intestinal metabolism of SDZ-RAD and rapamycin in rats.

The new immunosuppressive agent, SDZ-RAD, and its analog rapamycin were examined for intestinal absorption, metabolism, and bioavailability in Wistar rats. Intestinal first-pass metabolism studies from rat jejunum showed that at 0.5 mg of SDZ-RAD/kg rat, 50% of the parent compound was metabolized in the intestinal mucosa, and this decreased to around 30% when SDZ-RAD was increased to 5.0 mg/kg rat. Results for rapamycin at the low dose were similar to those for SDZ-RAD, but at the higher dose only 1 to 14% of the total rapamycin absorbed was metabolized by the intestine. After i.v. administration of 1 mg/kg SDZ-RAD or rapamycin, the area under the concentration curve (AUC) for rapamycin was twice that of SDZ-RAD, resulting in a systemic clearance of 6.2 ml/min and 3.0 ml/min for SDZ-RAD and rapamycin, respectively. However, the AUC for oral absorption was similar for the two compounds: 140 and 172 ng*h/ml for SDZ-RAD and rapamycin, respectively. Because blood clearance was faster for SDZ-RAD after i.v. administration, the absolute oral bioavailability for SDZ-RAD was 16% compared with 10% for rapamycin. Overall, the data suggest that intestinal first pass is a major site of metabolism for SDZ-RAD and rapamycin and that intestinal absorption of SDZ-RAD was much faster than that of rapamycin. This allowed it to counteract the combined actions of faster systemic clearance and increased intestinal metabolism, resulting in comparable absolute exposure when given orally. Also, the coadministration of cyclosporin A with SDZ-RAD was shown to dramatically increase blood AUCs for SDZ-RAD, probably through saturating intestinal metabolism mechanisms.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1998

In vitro and in situ absorption of SDZ-RAD using a human intestinal cell line (Caco-2) and a single pass perfusion model in rats: comparison with rapamycin.

PURPOSE: To compare the intestinal absorption and active efflux protein susceptibility of a new immunosuppressive agent (SDZ-RAD) with that of its analog rapamycin. METHODS: Caco-2 cell monolayers were used to examine bidirectional transport of the two compounds at low micromolar concentrations. Single pass rat intestinal perfusion was also used to examine steady state permeability. RESULTS: Rapamycin and SDZ-RAD showed a distinct preference for transport in the basolateral to apical direction of Caco-2 monolayers as efflux was >20 times greater than apical to basolateral transport. Efflux of SDZ-RAD was completely inhibited by verapamil while efflux of rapamycin was mostly inhibited by verapamil and partially inhibited by probenecid. Passive permeability was shown to be 20 x 10(-6) cm/sec for SDZ-RAD and 10 x 10(-6) cm/sec for rapamycin. In situ rat studies also showed the permeability of rapamycin to be half that of SDZ-RAD with permeabilities of 12.6 X 10(-6) for rapamycin and 24.8 x 10(-6) cm/sec for SDZ-RAD. CONCLUSIONS: SDZ-RAD and rapamycin are strong substrates for P-gp-like mediated efflux. Rapamycin is also partially removed from cells by a second efflux system that is not responsive to SDZ-RAD. When these efflux pumps are inhibited SDZ-RAD is likely to be absorbed across the intestine at a faster rate than rapamycin.

Animals↗
PubMed1998

Spatial-temporal analysis of mobility over the adult age range using the Postural-Locomotor-Manual Test.

BACKGROUND: Mobility measurements were performed on healthy adult subjects to investigate changes over the adult age range and to obtain reference values. METHODS: Ninety-five males (19-90 years, mean 58.2) and 122 females (19-90 years, mean 51.8) were measured using the commercially available Postural-Locomotor-Manual Test (PLM-test). Subjects are required to perform a standard maneuver that is recorded using an optoelectronic technique. RESULTS: Older subjects carried out all phases of the maneuver more slowly than younger subjects. At about the age of 50 years, females showed a more rapid slowing down. Males showed a more gradual decrease over the adult age range. CONCLUSION: The PLM-test provides a fairly simple noninvasive method of assessing motor performance. However, it is important to separate male and female data in the determination of reference values.

Adult↗
PubMed1998

Renal transplantation following renal failure due to urological disorders.

BACKGROUND: Renal allograft outcome, during an 8 year period (1985-1992), has been assessed in 56 renal transplants performed in 55 patients who had end-stage renal failure as a consequence of urological abnormalities. The abnormalities were: primary vesicoureteric reflux (VUR) or renal dysplasia (26 patients); posterior urethral valves (PUV) (15); neuropathic bladders (6); vesico-ureteric tuberculosis (5); bladder exstrophy (3); and prune belly syndrome (1). Six patients had augmented bladders, and eight transplants were performed in seven patients with urinary diversions. RESULTS: Overall, 1 and 5 year actuarial graft survival was 89 and 66%, with mean creatinine of 154 micromol/l +/- 11 (SE) and 145 +/- 9 respectively. Patients with abnormal bladders or conduits (n = 28) had worse graft function than those with normal bladders (n = 28) although graft survival was not significantly different in the two groups at 1 and 5 years: 93 and 75% with normal bladders vs 86 and 57% with abnormal systems. Symptomatic urinary tract infections were common in the first 3 months after transplantation (63%); fever and systemic symptoms occurred in 39% with normal bladders and 59% with abnormal bladders. Urinary tract infection directly contributed to graft loss in six patients with abnormal bladders, but had no consequences in those with normal bladders. CONCLUSIONS: Abnormal bladders must be assessed urodynamically before transplantation, and after transplantation adequacy of urinary drainage must be re-assessed frequently. Prophylactic antibiotics are now given for the first 6 months and urinary tract infections must be treated promptly. With these measures, good results, similar to those of patients without urological problems, can be obtained.

Adolescent↗
PubMed1997

The facet orientation circle. A new parameter for facet joint angulation in the lower lumbar spine.

STUDY DESIGN: A descriptive quantitative evaluation was done of the transverse orientation of the lower lumbar facet joints as measured by computed tomography scanning. OBJECTIVES: To evaluate a new parameter for facet joint angulation in the transverse plane (the "facet orientation circle") and to obtain reference values for this new parameter. SUMMARY OF BACKGROUND DATA: In other studies, both in vitro and in vivo, the angulation of the facet joints has been measured in degrees relative to the frontal or sagittal plane. These methods have some limitations. The parameter used in the present study has not been described in the literature. METHODS: Lower lumbar facet joint orientation was measured in 212 vertebral levels of 123 consecutive patients using the facet orientation circle parameter. Patients with degenerative or developmental abnormalities of the lumbar spine were excluded, as were those with technically inadequate computed tomography studies. RESULTS: Mean facet orientation circle diameters (+/-SD) were: L3-L4, 43.7 +/- 10.5 mm; L4-L5, 63.8 +/- 26.4 mm; and L5-S1, 82.3 +/- 23.5 mm. Differences between right and left sides were: L3-L4, 6.3 +/- 7.1 mm; L4-L5, 13.9 +/- 25.3 mm; and L5-S1, 17.9 +/- 16.2 mm, intra-observer variability was 2.3%. CONCLUSIONS: Measurement of facet joint angulation using the facet orientation circle is possible and reproducible. The morphometric data presented may be useful as a reference for biomechanical and clinical research of facet joint orientation and asymmetry.

Adolescent↗
PubMed1997

Effect of dietary cadmium on iron metabolism in growing rats.

Little is known regarding the interactions between iron and cadmium during postnatal development. This study examined the effect of altered levels of dietary iron and cadmium loading on the distribution of cadmium and iron in developing rats ages 15, 21, and 63 days. The uptake of iron, transferrin, and cadmium into various organs was also examined using 59Fe, [125I]transferrin, and 109Cd. Dietary cadmium loading reduced packed cell volume and plasma iron and nonheme iron levels in the liver and kidneys, evidence of the inducement of an iron deficient state. Dietary iron loading was able to reverse these effects, suggesting that they were the result of impaired intestinal absorption of iron. Cadmium loading resulted in cadmium concentrations in the liver and kidneys up to 20 microg/g in rats age 63 days, while cadmium levels in the brain reached only 0.16 microg/g, indicating that the blood-brain barrier restricts the entry of cadmium into the brain. Iron loading had little effect on cadmium levels in the organs and cadmium feeding did not lower tissue iron levels in iron loaded animals. These results suggest that cadmium inhibits iron absorption only at low to normal levels of dietary iron and that at high levels of intake iron and cadmium are largely absorbed by other, noncompetitive mechanisms. It was shown that 109Cd is removed from the plasma extremely quickly irrespective of iron status and deposits mainly in the liver. One of the most striking effects of cadmium loading on iron metabolism was increased uptake of [125I]transferrin by the heart, possibly by disrupting the process of receptor-mediated endocytosis and recycling of transferrin by heart muscle.

Absorption↗
PubMed1997

Comparison of free range and graded exercise testing.

Previous studies with athletes have demonstrated greater physiologic responses during free range (FR) compared with graded (GXT) exercise testing. Since the sensitivity of clinical exercise testing depends upon the magnitude of physiologic responses, we sought to determine whether FR might provoke greater responses than GXT in nonathletic individuals and patients. Healthy, physically active nonathletes and clinically stable CHD patients (N = 12) performed GXT on cycle ergometer (15 W + 15 W.min-1) and FR (minimal time for 75 kJ task) on a cycle ergometer. A starting power output was recommended for FR, but the patients were free to pedal at their own rates. During FR, VO2max (36.5 +/- 10.1 vs 34.1 +/- 9.4 mL.min-1.kg-1), HRmax (156 +/- 25 vs 144 +/- 27 beats.min-1), double product (31.4 +/- 4.9 vs 29.1 +/- 5.9) and VEmax (111 +/- 26 vs 94 +/- 17 L.min-1) were all significantly greater than during cycle GXT. The mean peak power output during GXT (180 +/- 45 W) was not significantly different than the mean power output during FR (204 +/- 45 W). During FR, successive "0.5 mile laps" (approximately 12.5 kJ) were accomplished at power outputs of 217 +/- 45, 217 +/- 52, 192 +/- 60, 194 +/- 65, 199 +/- 63, and 207 +/- 63 W. No patient experienced angina or ECG changes during either FR or GXT. The patients uniformly reported that FR felt like "hurrying" in the real world. Some patients had to make large reductions in their power output in mid ride to allow recovery from a too aggressive start, much as they would in the real world. We conclude that FR exercise provides a clinically useful method of exercise testing that is not only more like real world exercise patterns but also provokes greater physiologic responses than are achievable during conventional GXT.

Adult↗
PubMed1996

The effects of iron loading and iron deficiency on the tissue uptake of 64Cu during development in the rat.

This study examined the uptake of 64Cu by the brain, liver and other organs during development in rats aged 15, 21 and 63 days fed low, normal and high iron diets, using either a solution of 64CuCl2 chelated with nitrilo-triacetic acid (NTA) or 64Cu-ceruloplasmin (64Cu-Cp). 64Cu-NTA uptake was higher in the brain, spleen, kidneys, femurs and red cells at 15 days than at the later ages, while the liver took up most of the 64Cu in 63-day-old rats over the 2 h of the study. The brain had similar levels of 64Cu-NTA uptake at 15 and 21 days, even though liver uptake significantly increased, suggesting that Cu-NTA uptake by the brain increases from 15 to 21 days. The brain took up a greater percent of the injected dose of 64Cu-Cp than 64Cu-NTA yet, in either case, brain uptake was lower than that of the other organs. Iron loaded rats had significantly higher uptake of non-ceruloplasmin-bound 64Cu in all the organs examined, for at least one of the three ages, when compared with control rats. However, iron deficiency produced little change. Iron loading has a greater effect on 64Cu-Cp uptake than 64Cu-NTA, decreasing 64Cu uptake in the brain, liver, kidneys and femurs. Iron deficiency only increased 64Cu-Cp uptake in the liver. These results suggest that the mechanism of copper uptake by the liver is still maturing during suckling in the rat, and that ceruloplasmin receptor numbers are down regulated by iron loading, thus providing evidence of a new link between iron and copper metabolism.

Animals↗
PubMed1996

Fate and impact of pesticides applied to potato cultures: the Nicolet River basin.

The fate of cash-crop (potato) pesticides was monitored from the fields on which they were applied to the nearby streams. The investigation took place in the Nicolet River basin in the province of Quebec, Canada. The main pesticides under study were aldicarb, fenvalerate, metribuzin, and phorate. Aldicarb was never detected in any of the samples. The other pesticides were all detected in soils at low concentrations. Only fenvalerate and metribuzin were detected in tile drain. Metribuzin concentrations of up to 0.25 microgram/g were detected in the soil giving rise to a concentration of 1.3 micrograms/liter in tile drain and 47.1 micrograms/liter in surface runoff. Low concentrations of metribuzin up to 0.41 microgram/liter were detected in the nearby streams. The CREAMS model simulating pesticide movement in the fields overestimated metribuzin losses in the runoff at a concentration of 107 micrograms/liter. The subsurface EXPRES model using a PRZM time series adequately estimated a metribuzin field subsurface runoff concentration of 0.5 microgram/liter. According to the Canadian Water Quality Guideline for the protection of aquatic life, the concentrations of pesticides found in surface waters of this potato-growing region of Quebec do not have a potential to impact on the aquatic life in these systems.

Aldicarb↗
PubMed1996

Interactions between tissue uptake of lead and iron in normal and iron-deficient rats during development.

Environmental lead intoxication, which frequently causes neurological disturbances, and iron deficiency are clinical problems commonly found in children. Also, iron deficiency has been shown to augment lead absorption from the intestine. Hence, there is evidence for an interaction between lead and iron metabolism which could produce changes in lead and iron uptake by the brain and other tissues. These possibilities were investigated using 15-, 21-, and 63-old rats with varying nutritional iron and lead status. Dams were fed diets containing 0 or 3% lead-acetate and 0.2% lead-acetate in the drinking water. After weaning, 0.2% lead-acetate in the drinking water became the sole source of dietary lead. Measurements were made of tissue lead and nonheme iron levels and the uptake of 59Fe after intravenous injection of transferrin-bound 59Fe. Iron deficiency was associated with increased intestinal absorption of lead as indicated by blood and kidney lead levels in rats exposed to dietary lead. However, iron deficiency did not increase lead deposition in the brain, and in all rats brain lead levels were relatively low (< 0.1 microgram/g). Lead concentrations in the liver were below 2 micrograms/g, whereas kidneys had almost 20 times this concentration. Animals with iron deficiency had lower liver iron levels and had increased brain 59Fe uptake in comparison to control rats. However, iron levels in brain and kidneys were unaffected by lead intoxication regardless of the animal's iron status. 59Fe uptake rates were also unaffected by lead, but increased rates of uptake were apparent in iron-deficient rats. Lead did increase liver iron levels in all iron-adequate rats, but iron deficiency had little effect. It is concluded that, compared with other tissues, the blood-brain barrier largely restricts lead uptake by the brain and that the uptake that does occur is unrelated to the iron status of the animal. Also, the level of lead intoxication produced in this investigation did not influence iron uptake by the brain and kidneys, but liver iron stores could be increased if iron levels were already adequate.

Aging↗
PubMed1996

Iron and copper interact during their uptake and deposition in the brain and other organs of developing rats exposed to dietary excess of the two metals.

This study examined the effect of iron and copper loading on rat brain, liver, kidney, femur, blood and plasma concentrations of these metals and iron transport into the organs during development. Dams were fed control diets or iron-loaded diets (20 g/kg carbonyl iron) with either distilled water or copper-loaded water (350 mg/L) beginning at d 20 of pregnancy. The weanlings also had access to the diets and water supply and were examined at 15, 21 and 63 d of age. The iron content of the liver was 17- to 30-fold greater in iron-loaded rats than in controls, whereas liver, kidney and plasma copper levels generally were lower. Iron loading alone did not increase brain iron concentrations, suggesting the blood-brain barrier is already developed at birth. However, dual loading of iron and copper resulted in elevated concentrations of brain non-heme iron and copper in 15- and 63-d-old rats compared with animals loaded with iron alone. These results suggest that brain iron uptake mechanisms may be different when excess copper is present. Liver non-heme iron was also greater in copper-loaded rats, irrespective of iron status. However, kidney iron concentrations generally were not affected by dietary copper. In rats fed the copper-containing diet, the uptake of iron into brain and liver was significantly lower than in those fed the control diet, suggesting that copper loading can decrease iron uptake into organs. It is concluded that combined dietary supplementation with iron and copper can alter the metabolism of each metal. These changes are age and organ dependent. Developing rats may be very susceptible to these combined overload states because significant effects are seen in early adulthood.

Animals↗
PubMed1995

Characterization of human gait by means of body center of mass oscillations derived from ground reaction forces.

Ground reaction forces from two force plates are used to determine the cyclic oscillations of the body center of mass while walking at preferred speed. Good approximations to the oscillations may be obtained from formulae containing just the first- and second-order Fourier coefficients of the combined left-right ground reaction forces taken over a complete walking cycle. The symmetric components of the oscillations have consistent mutual phase relations for normal subjects, so that the amplitudes alone can be used as sufficient parameters to characterize the body center of mass oscillations. The analytical technique enables detection of small but consistent gait asymmetries.

Adolescent↗
PubMed1994

Effects of chelators on iron uptake and release by the brain in the rat.

The iron chelators desferrioxamine (DFO), pyridoxal isonicotinoyl hydrazone (PIH), 2,2'-bipyridine, diethylenetriamine penta-acetic acid (DTPA) and 1,2 dimethyl-3-hydroxy pyrid-4-one (CP20) were analysed for their ability to change 59Fe uptake and release from the brain of 15- and 63-day rats either during or after intravenous injection of 59Fe-125I-transferrin. DTPA was the only chelator unable to significantly reduce iron uptake into the brain of 15-day rats. This indicates that iron is not released from transferrin at the luminal surface of brain capillary endothelial cells. CP20 was able to reduce iron uptake in the brain by 85% compared to 28% with DFO. Only CP20 was able to significantly reduce brain iron uptake in 63 day rats. Once 59Fe had entered the brain no chelator used was able to mediate its release. All of the chelators except CP20 had similar effects on femur iron uptake as they did on brain uptake, suggesting similar iron uptake mechanisms. It is concluded that during the passage of transferrin-bound iron into the brain the iron is released from transferrin within endothelial cells after endocytosis of transferrin.

2,2'-Dipyridyl↗