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Biomedical subjects

A J Collins

Publications and source records attributed to A J Collins.

At least 19 recordsLinked to original sources
PubMed1992

Structured approach to the investigation of anaemia in patients with rheumatoid arthritis.

A group of 28 patients with rheumatoid arthritis who were severely anaemic were investigated for iron deficiency. On the basis of bone marrow studies, the patients were divided into two groups, those with and those without signs of stainable iron in the marrow. This grouping did not distinguish between the severity of their rheumatoid arthritis measured by clinical parameters. Measurement of the red cell count and biochemical parameters in the peripheral blood showed a statistical difference in red cell size, haemoglobin content, and iron binding capacity between the two groups. The statistical variation of these parameters, however, did not allow these measurements to predict bone marrow iron deficiency in any subject. Investigation of the upper gastrointestinal tract by endoscopy showed that acute macroscopic lesions were infrequently associated with anaemia. It was concluded that anaemia in association with rheumatoid arthritis may mimic iron deficiency anaemia, and that simple investigations of the peripheral blood do not accurately show the iron status of the reticuloendothelial system in the presence of a chronic inflammatory disease. For the investigation of severe anaemia in rheumatoid arthritis, bone marrow assessment of iron status should be performed as the initial investigation. In addition, iron deficient patients require investigation of the lower and the upper gastrointestinal tract.

Administration, Oral↗
PubMed1991

The comparative pharmacokinetics of acemetacin in young subjects and elderly patients.

Single and multiple dose pharmacokinetics of acemetacin in 10 young healthy subjects and 10 elderly patients with osteoarthritis were studied. Peak plasma concentrations of acemetacin and its metabolite, indomethacin, were found between 2.4 and 4 h after an oral dose of the drug. After dosing to steady state (7 days), the mean plasma elimination half-life for acemetacin was 1.1 h and 1.0 h, and for indomethacin 7.1 h and 7.2 h in the young and elderly groups respectively. Statistical analysis of tmax, AUC, plasma t1/2 and residual drug concentrations for acemetacin or indomethacin revealed no significant differences (P greater than 0.05) between young subjects and elderly patients after acute or chronic dosing. The results suggest that drug accumulation did not occur in the elderly subjects over the time period studied and that, on pharmacokinetic grounds, dose adjustment in the elderly is unlikely to be required.

Adult↗
PubMed1991

Renal failure in disasters.

This article focuses on the steps that both search and rescue teams and advanced medical teams may use to reduce the potential for acute renal failure from crush injury in disasters and provides guidelines for the deployment of dialytic resources in the disaster setting.

Acute Kidney Injury↗
PubMed1990

Galactose inhibits lactase expression by mouse jejunal enterocytes.

Present work uses a combination of quantitative cytochemistry and measurements of cell migration rates to describe galactose effects on lactase expression by mouse enterocytes. Mice fed galactose were found to eat less, weigh less and drink more than mice maintained on a low-carbohydrate isocalorific diet. The enterocyte migration rate in these mice was also only one third of that determined in low-carbohydrate-fed animals. The rate at which lactase activity increased in the brush border membrane of migrating enterocytes was 3-times greater in low-carbohydrate- compared with galactose-fed mice. The time during which this increase persisted was, however, 3-times less in low-carbohydrate-fed animals. The maximum rate of sucrase-maltase appearance, measured as control in these experiments, remained unaffected by galactose feeding. Galactose effects on lactase expression might in part result from mice being unable to metabolise this substrate. Previously it has been stated that galactose increases lactase biosynthesis in rat intestine (Koldovsky, O., Bustamonte, S. and Yamada (1981) In Mechanisms of intestinal adaptation (Robinson, J.W.L., Dowling, R.H. and Ricken, E.O., eds.), pp. 153-156, MTP Press, Lancaster). This result is discussed in relation to the opposite finding reported in the present work for mouse jejunal enterocytes. The need to relate enzyme appearance to age and developmental state of enterocytes in this type of study is also emphasized.

Animals↗
PubMed1990

Changing risk factor demographics in end-stage renal disease patients entering hemodialysis and the impact on long-term mortality.

Patient survival on hemodialysis has previously been shown to be associated with the presence of comorbid conditions on entrance. Significant comorbid conditions are atherosclerotic heart disease (ASHD), cerebral vascular disease (CVD), nonskin malignancies, chronic obstructive pulmonary disease, diabetes mellitus, and age on entrance to dialysis. Changes in annual mortality have been noted in the United States and at the Regional Kidney Disease Program. The increase in annual mortality was analyzed to determine the impact of risk factors during the time intervals 1976 to 1982 and 1983 to 1987. Patients with no major risk factors have longer survival rates and lower deaths per 1,000 treatment-months from 1983 to 1987 compared with 1976 to 1982. Diabetics have survival rates and deaths per 1,000 treatment-months that are comparable up to age 75. However, over age 75, diabetics have lower survival rates and higher death rates. The presence of comorbid conditions in the diabetic group is high and may account for the increased death rate. The percent of diabetics entering the program has increased from 29% to 48% over the intervals. Nondiabetics with comorbid conditions on entrance had higher deaths per 1,000 treatment-months from 1983 to 1987 compared with 1976 to 1982 across all age categories. Risk factor analysis shows that nondiabetics with major risks are entering with increasing numbers and continuation of comorbid conditions that impact death rates. Peripheral vascular disease, originally not significantly associated with death on dialysis, has dramatically increased from 18% to 60% in nondiabetics with comorbid conditions. In the patients over age 60 with comorbid conditions, 75% of patients now entering dialysis have peripheral vascular disease (PVD). In summary, major shifts in the hemodialysis population have occurred. Diabetics entering dialysis now account for almost 50% of all patients, with the older group having more comorbid conditions. This change alone would increase the annual mortality rate. Patients with comorbid conditions now enter with a higher prevalence of multiple comorbid conditions, which would increase the annual mortality rate. Nondiabetics without comorbid conditions now have better survival across all age categories compared with the previous data. PVD, with its current high prevalence, needs to be reevaluated as a significant risk factor for death on hemodialysis. Therefore, the increase in the annual gross mortality rate is highly predicted based on the change in the diabetic population and the increase in single and multiple comorbid conditions in the nondiabetic population.

Adolescent↗
PubMed1990

Body fluid spaces and blood pressure in hemodialysis patients during amelioration of anemia with erythropoietin.

Blood pressure (BP) may increase in hemodialysis patients during treatment of anemia with recombinant human erythropoietin (r-HuEPO). Since fluid volume is a determinant of BP in dialysis patients, changes in body fluid spaces during r-HuEPO therapy could affect BP. Thus, 51Cr-labeled red blood cell (RBC) volume, inulin extracellular fluid (ECF) volume, and urea total body water (TBW), as well as cardiac output, plasma renin activity (PRA), and plasma aldosterone concentration were determined postdialysis before and after r-HuEPO therapy in patients in whom changes in BP could be managed by ultrafiltration alone. Eleven patients entered the study: one had a renal transplant and two required addition of antihypertensive drug therapy and were excluded; eight, of whom two required antihypertensive drug therapy following the study, were included in the analyses. Results revealed an increase in predialysis hemoglobin from 67 to 113 g/L (6.7 to 11.3 g/dL) (P = 0.001) during 18 +/- 6 weeks of therapy. Predialysis diastolic BP increased from 80 to 85 mm Hg (P = 0.07), while postdialysis diastolic BP was unchanged at 73 mm Hg. 51Cr-RBC volume increased, from 0.7 to 1.3 L (P = 0.004). ECF tended to decrease, from 13.7 to 10.8 L (P = 0.064), while TBW decreased to a similar extent, but not significantly, 34.3 to 31.2 L (P = 0.16). Postdialysis ECF volume was positively correlated with mean arterial BP at baseline (r = 0.89, P = 0.007) and after therapy (r = 0.74, P = 0.035). However, the regression lines for this relationship were different (P = 0.022) before and after therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Sugar-dependent selective induction of mouse jejunal disaccharidase activities.

1. Sugar-containing diets chosen not to affect intestinal structure or enterocyte turnover have been fed to mice previously maintained on a low carbohydrate diet in order to determine their ability to induce disaccharidase enzymes in the small intestine. 2. Glucose-, fructose- and 3-O-methyl-glucose-containing diets increased sucrase and maltase but not lactase activities in mouse jejunal homogenates. These effects were either absent or negligible in more distal regions of the small intestine. 3. Placing mice on glucose-, fructose- or 3-O-methyl-glucose-containing diets was further shown, by quantitative cytochemistry, to cause a 1.6-, 2.6- and 3.2-fold increase in the initial rate at which alpha-glucosidase activity (sucrase + maltase) appeared in the brush-border membrane of developing enterocytes. 4. The time during which alpha-glucosidase activity increased in enterocyte brush-border membranes fell from 30 h for low carbohydrate fed mice to 21, 19 and 17 h in mice fed glucose, fructose and 3-O-methyl-glucose respectively. Change of diet had no effect on the kinetics of lactase expression by developing enterocytes. 5. Maximal alpha-glucosidase activity detected in enterocyte brush-border membranes is equal to RT, where R is the initial rate of enzyme appearance and T is the time during which this rate operates. The ability of sugars to increase R selectively, but only at the expense of T, defines unexpected limits to the capacity of enterocytes to adapt to changes in luminal nutrition. 6. The above results are discussed in relation to other aspects of enterocyte differentiation recently subjected to quantitative analysis. The need to standardize other aspects of intestinal physiology and redefine the energy content of diets containing non-metabolizable substrates in this type of work is also emphasized.

3-O-Methylglucose↗
PubMed1988

Coronary artery bypass surgery in patients on maintenance dialysis: long-term survival.

Coronary artery bypass grafting (CABG) can be performed with acceptable risk and results in symptomatic improvement in patients with end-stage renal disease (ESRD). However, the effect of CABG on long-term survival in these patients is unknown. We retrospectively identified 39 patients (group 1) with ESRD who underwent CABG for intractable angina between January 1975 and February 1987 while on maintenance dialysis. Thirty-nine dialysis patients (group 2) were also retrospectively selected for comparison and matched for age, sex, year of initiation, length of time on dialysis, and presence of diabetes mellitus and atherosclerotic heart disease at initiation of dialysis. Using life-table analysis, survival probability (with 95% confidence limits) was determined from the time of CABG for group 1 or after an equivalent period of time on dialysis for group 2. Two life-table analyses were performed; one with study end-points of death, withdrawal (renal transplantation, transfer to other dialysis facilities, and reoperation), and alive on dialysis; and a second with identical end points except that noncardiac deaths were treated as withdrawals. Coronary arteriography revealed severe three vessel disease, left ventricular dysfunction, and segmental wall motion abnormalities in most patients. A mean (+/- SD) of 2.56 +/- 0.75 vessels were bypassed with an operative mortality (30 days) of 2.6%. Mean follow-up after CABG in group 1 was 34.9 +/- 30.1 months, and in most patients functional classification improved. Mean follow-up for group 2 was 17.2 +/- 15.2 months. Two-year survival was 91.7% in group 1 and 51.4% in group 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1988

A prospective endoscopic study of the effect of Orudis and Oruvail on the upper gastrointestinal tract, in patients with osteoarthritis.

The effect of ketoprofen, a nonsteroidal anti-inflammatory drug, was tested on the upper gastrointestinal tract (UGIT) in patients with osteoarthritis. The drug was given in two forms; as simple ketoprofen (Orudis) and as a slow release preparation (Oruvail), when the drug was not released into the stomach, but into the small intestine. These formulations were compared with indomethacin for endoscopically proven damage to the UGIT. Orudis and Oruvail produced similar damage to previously normal UGITs over 56 days; each formulation produced about a 50% incidence of ulceration and inflammation. Indomethacin, by comparison produced less damage. The results suggested that the direct action of ketoprofen (barrier breaking effect) adds little to the mechanism of gastric cytotoxicity of this drug, which may be assumed to be predominantly caused by a systemic effect of ketoprofen on gastric cytoprotective mechanisms.

Administration, Oral↗
PubMed1988

Anaemia in patients with arthritis: are simple investigations helpful?

The level of haemoglobin, serum iron, total iron binding capacity and ferritin were measured in patients with rheumatological conditions who were anaemic at the time of upper gastrointestinal endoscopy. These parameters were similar in patients with or without lesions of their upper gastrointestinal tract, and in patients with a positive or negative faecal occult blood result. Lesions of the upper gastrointestinal tract were not more frequent in patients with a microcytic anaemia when compared to those with a normocytic anaemia, nor were they found more frequently in patients with a positive faecal occult blood test. Lesions visible at upper gastrointestinal endoscopy are not an important cause of microcytic anaemia in patients with arthritis. The finding that patients with normocytic anaemia are more likely to proceed to lower bowel examination than patients with microcytic anaemia is a reflection of the difficulty in interpretation of these simple haematological tests and showed they were unhelpful in determining which patients warrant investigation of the lower bowel. The frequency of further investigation of the lower bowel was significantly reduced by a positive endoscopy report, irrespective of the nature of the lesion, but was not significantly increased by finding faecal occult blood. We suggest that patients with arthritis selected for investigation of possible gastrointestinal blood loss should follow an organized plan of investigation that includes examination of both upper and lower bowel, and which should proceed uninfluenced by pro tem results. Unfortunately the selection of patients for such further investigation is hampered by a lack of simple discriminatory tests.

Aged↗
PubMed1988

Intra-articular apatite deposition in mixed connective tissue disease: crystallographic and technetium scanning characteristics.

An acute arthritis in a patient with mixed connective tissue disease (MCTD) was found to be associated with intra-articular deposition of carbonated hydroxyapatite crystals. A technetium hydroxymethylene diphosphonate bone scan showed intense uptake in the delayed phase scan of the affected joints. Synovial fluid analysis demonstrated uptake of the radiopharmaceutical drug directly onto the crystals.

Adult↗
PubMed1987

Systemic absorption of oral vancomycin in patients with renal insufficiency and antibiotic-associated colitis.

The systemic absorption of orally administered vancomycin was evaluated in five patients (six occasions) with moderate to severe renal insufficiency and documented antibiotic-associated colitis. The patients' ages ranged from 28 to 63 years and weights varied from 50.0 to 76.2 kg. Vancomycin doses were 125 mg (one case), 250 mg (three cases), and 500 mg (two cases) every six hours. Multiple serum concentrations were obtained (range four to 19) during the seven- to 28-day courses of vancomycin therapy. Vancomycin serum concentrations were detectable in five of the six cases as soon as two hours after the first dose, and plateaued within four days. A linear relationship between daily dose and the vancomycin serum concentration was observed (r = .8575, P less than .01). Routine monitoring of vancomycin serum concentrations in adult patients may not be necessary unless high dose (greater than 2 g/d) or prolonged therapy (greater than ten days) is required.

Administration, Oral↗
PubMed1987

Upper gastrointestinal findings and faecal occult blood in patients with rheumatic diseases taking nonsteroidal anti-inflammatory drugs.

An upper gastrointestinal endoscopic examination was performed, following a test for faecal occult blood, on a group of 108 patients with rheumatic complaints. The majority of the group studied had rheumatoid arthritis (RA) and 50% of the total group were anaemic. Every patient was taking a single nonsteroidal anti-inflammatory drug (NSAID). When the finding of blood in the faeces was compared with findings in the upper gastrointestinal tract, approximately half the subjects with ulcerative and inflammatory lesions had a positive test for blood. However, 50% of the subjects with an apparently normal upper gastrointestinal tract had a positive test for blood in the stool and these comprised the largest group of those examined. It was concluded that the finding of a positive faecal occult blood in such subjects is a poor indicator of ulcerative or inflammatory lesions of the upper gastrointestinal tract. The possible reasons for a finding of blood in the stool of patients taking NSAID who apparently have a normal upper gastrointestinal tract is discussed.

Anti-Inflammatory Agents, Non-Steroidal↗