Platelet preservation. I. The use of decrease in light absorbance as a screening method in cryopreservation studies on human platelets.
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Blood Platelets↗
Biomedical subjects
J Odink
Publications and source records attributed to J Odink.
Platelet preservation. II. The response of human platelet suspensions to hypotonic stress.
1. Platelet suspensions were exposed to hypotonic stress. Several parameters of the changes in light absorbance were investigated i.a. the initial decrease in absorbance (A min), the maximal rate of the recovery process (V max), and the value of the absorbance two hours after mixing the platelet suspension with the hypotonic solution. 2. The ratio V max/A min appeared to be independent of both platelet concentration and, within a specific range, decrease in osmolarity. 3. Cryoprotectants appeared to disturb the response to hypotonic stress. 4. Cryopreservation caused a decrease in the light absorbance of the platelet suspension, of A min, and of the recovery process.
Absorption↗
Platelet preservation. III. The influence of dimethylsulfoxide and cooling conditions on serotonin uptake velocity and response to hypotonic stress of human platelets.
1. Serotonin uptake velocity of human platelets was found to be reversibly inhibited by the presence of dimethylsfulfoxide (DMSO). 2. Incubation of platelet concentrates in the presence of DMSO for 90 minutes at room temperature decreased serotonin uptake velocity and response to hypotonic stress. 3. The serotonin uptake velocity was not substantially influenced by the temperature of incubation with DMSO. 4. The best recovery of serotonin uptake velocity after cryopreservation in the presence of DMSO was observed when DMSO was added quickly before cooling and removed quickly after thawing. 5. No significant differences were observed in serotonin uptake velocity and response to hypotonic stress cryopreservation in the presence of DMSO when cooling rates were varied from 2 to 10 degrees C/min.
Blood Platelets↗
Experiments on the preparation of blood components with the IBM 2991 blood cell processor.
Experiments were carried out with the IBM 2991 Blood Cell Processor in order to study the sedimentation behaviour of blood cells from human ACD blood during centrifugation. Based on this behaviour procedures were developed for plasmapheresis and leucapheresis using the Blood Cell Processor. Accumulation of platelets was observed to occur at the plasma-cell interface during centrifugation at 1,000 g; this led to the development of a one-step method for the preparation of platelet concentrates.
Blood Cell Count↗
The interaction of the lipase inhibitor orlistat with ethanol in healthy volunteers.
OBJECTIVES: The primary objective was to investigate the possible interference of ethanol on the orlistat effect on inhibition of dietary fat absorption and the possible interference of orlistat on the pharmacokinetics of ethanol. Secondary objectives were to assess the tolerability during concomitant dosing of orlistat and ethanol and to determine the ethanol effect on plasma levels of orlistat. METHODS: This was a double-blind, placebo-controlled, parallel, randomized study performed in 30 (three parallel groups of ten subjects each) healthy normal weight male subjects between the ages of 20 and 30 years. A 5-day run-in period to accustom subjects to a standardized diet of 2500 kcal/day (30% fat) and to establish baseline fecal fat excretion was followed by a 6-day treatment period. Subjects were randomly assigned to one of three treatment groups (A = orlistat 120 mg t.i.d. and ethanol placebo, B = orlistat 120 mg t.i.d. and 40 g ethanol qd on days -1 and 6, and 40 g bid on days 1-5, and C = orlistat placebo tid and 40 g ethanol qd on days -1 and 6, and 40 g b.i.d. on days 1 5). Serial blood samples were collected for determination of ethanol serum concentrations at specified times over 5 h after each dose of ethanol on days -1 and 6, and for determination of orlistat plasma concentrations on days 1, 3, 5, and 6. Feces were collected quantitatively on days -5 through 8 for analysis of fecal fat. RESULTS: The means of baseline-corrected fecal fat excretion values were comparable: 23.7 g for group A (orlistat) and 22.7 g for group B (orlistat and ethanol). No significant difference was found regarding ethanol pharmacokinetic parameters between treatments with orlistat and placebo. No apparent differences existed between the number of plasma samples with measurable orlistat concentrations in groups A and B. CONCLUSION: Concomitant ingestion of social amounts of ethanol did not alter the inhibitory effect of orlistat on dietary fat absorption during short-term treatment (6 days) with orlistat. Short-term treatment with orlistat had no significant influence on ethanol pharmacokinetics.
Adult↗
Amino acids and glucose in human cerebrospinal fluid after acute ischaemic brain damage.
In the search for potential biochemical markers of value for prognosis after acute hypoxic brain damage, amino acids and glucose were assessed in the cerebrospinal fluid (CSF) and glucose in blood. Samples were taken by lumbar puncture 4, 28, 76 and 172 h after resuscitation from 20 patients and once from 10 control patients. Eight of the resuscitated patients recovered neurologically but 12 remained comatose. The concentrations of alanine (P less than 0.001) and phenylalanine (P less than 0.035) differed most in 4-h samples between the groups. The concentration of alanine was higher in all patient groups with hypoxic brain damage as compared to the controls, the concentrations in patients dying within 76 h (disabled-s group) being higher than in the recovered patients. Phenylalanine in the disabled-s group was significantly higher than the control value. Furthermore, there were significant differences between various patient groups in the concentrations of glutamine, isoleucine, leucine, lysine, serine, tyrosine and valine. When taking into account the permeability of the BBB to these amino acids, alanine, valine and isoleucine most clearly represent brain amino acid metabolism. CSF glucose in the control group and in the recovered patients was lower than in patients dying within 76 h.
Acute Disease↗
Platelet preservation V. Survival, serotonin uptake velocity, and response to hypotonic stress of fresh and cryopreserved human platelets.
The survival in vivo of 51Cr-labeled autologous human platelets, the serotonin uptake velocity, and the response to hypotonic stress were determined both before and after cryopreservation. Changes in platelet survival corresponded to changes in serotonin uptake velocity and response to hypotonic stress. No correlation was observed between the values of the survivla in vivo, the serotonin uptake velocity, and the response to hypotonic stress within the separate suspensions of fresh and cryopreserved platelets. There was no indication that hypercoagulability was induced by infusion of small amounts of cryopreserved platelets.
Blood Platelets↗
Platelet preservation. IV. Preparation and cryopreservation of platelet concentrates from fresh and overnight-stored human blood.
Two methods were used for the preparation of platelet concentrates from fresh and overnight-stored human ACD blood. In a two-step method prostoglandin E1 was added to platelet rich plasma and the mixture was centrifuged to obtain platelet concentrate. The IBM 2991 Blood Cell Processor was used in a one-step method. The concentrates were stored in the frozen state. Concentrates prepared with the two-step method had a higher platelet recovery and a lower leukocyte contamination than did concentrates prepared with the one-step method. Based on serotonin uptake volocity, response to hypotonic stress and available platelet factor 3, no essential differences were observed between platelet concentrates prepared from fresh and overnight-stored blood. Concentrates prepared with the one-step method had a higher serotonin uptake velocity than those prepared with the two-step method. This did not result in a better recovery after cryopreservation.
Blood Cell Count↗
Circadian and circatrigintan rhythms of biogenic amines in premenstrual syndrome (PMS).
Circadian and circatrigintan (menstrual) rhythms in biogenic amines were studied in premenstrual syndrome (PMS). Selection of patients and controls was based on assessment of Menstrual Distress Questionnaires (MDQs). Patients showed a clear increase in menstral tension symptoms in the week before menstruation, both during selection and during the study. In the group of control subjects, there was hardly any increase in average MDQ symptoms during the late luteal phase. Diurnal urine and nocturnal urine were collected on days 5, 11, 17, 21, and 25 of the cycle. Blood was sampled from subjects in supine position through an intravenous (iv) catheter the morning after urine collection. Patients showed a higher tryptophan (Trp) and epinephrine (Epi) level in plasma, higher excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) in urine and a larger volume of 24-hr urine. Excretion of norepinephrine (NE) in 24-hr urine showed a linear increase during the cycle, while excretion of dopamine (DA) showed a quadratic pattern, being lowest at day 17. Homovanillic acid (HVA) and MHPG gave cubic patterns, i.e., an increase during the follicular phase, followed by a decrease after ovulation and a subsequent increase in the late luteal phase. Plasma Epi showed a linear decline during the cycle in patients, but not in control subjects. Excretion of NE, Epi, vanilmandelic acid (VMA), and HVA in urine was higher during the day than at night. The results of this study suggest that the metabolism of biogenic amines in patients suffering from PMS differs from that in control subjects, but that, except for plasma Epi, changes do not parallel the actual presence of PMS symptoms.
3,4-Dihydroxyphenylacetic Acid↗
Biogenic amines in anorexia nervosa: circadian rhythm in urinary excretion and influence of posture and physical task load on plasma catecholamines.
To investigate the sympathetic response in anorexia nervosa (AN) patients to stimuli occurring in normal life, biogenic amines were studied in 10 female outpatients. As control groups 10 lean and 10 normal weight healthy female subjects were included. It was hypothesized that the lean control group would have intermediate values between the AN patients and the normal weight controls. The AN patients and the lean controls had a mean underweight of 33.1% and 13.7%, respectively. For the excretion in 24-hr urine, differences among the groups were observed for several compounds, unexpectedly the values being lowest for the patients and highest for the lean controls. Furthermore, the lean controls had a higher excretion of a number of compounds in diurnal than in nocturnal urine, whereas this effect was absent or reversed for the AN patients and intermediate for the normal weight controls. Plasma norepinephrine was highest in the patients and lowest in the lean controls. The catecholamine response to postural changes and physical exercise did not differ among the groups. The results obtained indicate neither a (linear) relationship between underweight and the metabolism of biogenic amines nor a disturbed response to sympathetic stimulation in AN, but suggest an altered metabolism of biogenic amines in patients suffering from AN.
3,4-Dihydroxyphenylacetic Acid↗
Influence of dietary composition on the inhibition of fat absorption by orlistat.
Orlistat, a potent and selective inhibitor of gastrointestinal lipases, is designed for the treatment of obesity. The effect of orlistat on dietary fat absorption, when it was administered with diets differing in fibre content (high and low) and accessibility of fat (intra- and extracellular fat), was investigated in 32 hospitalized healthy males, according to an open, two-factorial study design. The subjects were randomly allocated to one of four parallel groups of equal size: A = intracellular fat, high fibre (28 g/day); B = extracellular fat, high fibre; C = extracellular fat, low fibre (9 g/day); or D = intracellular fat, low fibre. After a 5-day run-in period to accustom the volunteers to the standardized diet (2500 kcal and 84 g fat per day) and to establish baseline faecal fat parameters, they received 80 mg orlistat, three times daily mid-way through each meal for 8 days. Faeces were collected to measure total fat and free fatty acid excretions. The mean baseline-corrected excretion (% of dietary fat) in groups A, B, C and D, respectively, was 37.0, 30.4, 30.3 and 34.5 for total fat, and 6.5, 4.3, 2.6 and 3.9 for free fatty acids. The 95% confidence intervals for the difference between the means for high fibre and low fibre groups and for intracellular fat and extracellular fat groups, respectively, were 1.4 +/- 4.9 and 5.5 +/- 4.9 for total fat, and 2.2 +/- 3.1 and 1.9 +/- 3.1 for free fatty acids. The statistically significant difference (P < 0.05) in total faecal fat between intracellular fat and extracellular fat groups, in absolute terms < 5 g fat/day, was not regarded as clinically relevant. Under the conditions of this study, dietary fibre content and accessibility of fat had no relevant effect on the inhibition of fat absorption by orlistat.
Adult↗