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Biomedical subjects

S Holme

Publications and source records attributed to S Holme.

At least 73 records · Page 4Linked to original sources
PubMed1989

Evaluation of 99mtechnetium/51chromium post-transfusion recovery of red cells stored in saline, adenine, glucose, mannitol for 42 days.

An in vivo and in vitro study of 42-day saline, adenine, glucose, mannitol (SAGM) red cells (Terumo Corporation, Elkton, Md.) was conducted using 20 volunteers to document in vivo efficacy and analyze the validity of the 99mTc/51Cr technique. In vivo autologous post-transfusion recovery was measured by a double-label procedure involving the use of 99mTc-labeled freshly drawn red cells to quantify recipient blood volume and 51Cr to document both post-transfusion 24-hour recovery (PTR) and red cell survival. As an internal control, 5 of the 20 donors studied had red cell volumes estimated by the 125I-albumin (RISA) plasma volume technique on a separate occasion. For comparison, PTR was also calculated according to the single-label 51Cr protocol in which recipient blood volume was estimated by extrapolation from circulating 51Cr-labeled red cell activity 5-15 min after infusion. After 42 days of storage, PTR averaged 78 +/- 6% with the double-label 99mTc/51Cr technique and 81 +/- 5% with the single-label (51Cr alone), confirming a small difference between the two techniques. Correlation between the two techniques was high, r = 0.81, though the average 3% difference between them was significant (p less than 0.05). Red cell volumes of the 5 donors measured by both the 99mTc-red cell method and the 125I-albumin method exhibited excellent correlation, r = 0.96, and averaged 1,961 +/- 420 ml and 2,048 +/- 381 ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1988

Elevated levels of PA IgG in thrombocytopenic patients are not related to the presence of microthrombocytes or megathrombocytes.

Platelet-associated (PA) IgG levels were measured on peripheral blood samples from 63 thrombocytopenic patients with the use of fluorescein isothiocyanate (FITC)-conjugated anti-IgG antibody. Test specificity was investigated by examining the influence of variables such as the platelet count in platelet-rich plasma (PRP), platelet loss after the assay procedure, and platelet size distribution (including the percentage of microthrombocytes and megathrombocytes) on the PA IgG levels. Additionally, PA IgG levels were compared with PA albumin levels and with levels of nonspecific adherence of FITC anti-IgG by the platelets to ascertain if elevated levels were specific. Elevated PA IgG levels showed only significant correlations (P less than 0.05) with a mean platelet size below normal range and to increased PA albumin levels but not to PRP count, platelet loss after assay procedure, the percentage of microthrombocytes and megathrombocytes, and nonspecific adherence of FITC anti-IgG.

Albumins↗
PubMed1988

Increased levels of platelet associated IgG in patients with thrombocytopenia are not confined to any particular size class of platelets.

Patients with immune thrombocytopenia have an increased percentage of microthrombocytes/platelet fragments and megathrombocytes. It has been suggested that increased levels of platelet associated IgG (PA-IgG) found in these patients might be related to the presence of this abnormal platelet size distribution. In this study we used flow cytometry to investigate the distribution of PA-IgG within a population of platelets and, in particular, we examined the relationship between platelet size and PA-IgG determined simultaneously on individual platelets. Platelet samples from 10 normals and 31 thrombocytopenic patients were studied. PA-IgG was estimated using immunofluorescent FITC anti-IgG antibody. Binding of FITC anti-IgG to the platelets was quantitated in the flow cytometer as relative mean fluorescence (RMF) which was calibrated against values (in fg/plt of FITC anti-IgG) obtained by spectrofluorometry after solubilization of the platelets. A high correlation (r = 0.89) was found between flow cytometric RMF value and spectrofluorometric FITC anti-IgG values. The flow cytometric studies showed that platelet samples with abnormally elevated levels of FITC anti-IgG (greater than 1.7 fg/plt) not only have a higher percentage of platelets with elevated FITC anti-IgG, but that these platelets also have increased levels of FITC anti-IgG as compared to platelets from normal samples. Platelet size was measured by the amount of forward light scatter in the flow cytometer. A low but significant correlation (r = 0.33 +/- 0.12) was found between size (FALS) and fluorescent signals in samples with elevated FITC anti-IgG. The contribution of 10% of the smallest platelets by FALS and 10% of the largest platelets by FALS to the total levels of flow cytometer platelet fluorescence in these samples was only 4.4% and 19.4% respectively which was not higher than obtained with samples with normal levels of FITC anti-IgG. In conclusion, this study showed that increased levels of PA-IgG found among thrombocytopenic patients were not confined to any particular size class of platelets.

Blood Platelets↗
PubMed1988

Light scatter and total protein signal distribution of platelets by flow cytometry as parameters of size.

The use of flow cytometry for determination of platelet size was investigated by measurement of forward-angle light-scatter (FALS) signals and the fluorescent right-angle signals from platelets incubated with the fluorescent protein dye fluorescein isothiocyanate (FITC). Both FALS and fluorescence signals displayed a unimodal log normal pattern of distributions that were almost identical to distributions obtained by resistive particle sizing. As measured on 12 platelet samples from normal individuals, FALS, FITC, and resistive particle size data exhibited a high degree of fit to log normal distributions as shown by the coefficients of determination (R2), which were 0.9962 +/- 0.0035, 0.9966 +/- 0.0056, and 0.9987 +/- 0.0012, respectively. The geometric standard deviation (GSD), reflecting the heterogeneity of the FALS, FITC, and resistive particle size signals, was almost identical: 1.69 +/- 0.03, 1.67 +/- 0.04, and 1.69 +/- 0.02, respectively, for spherical platelets from normal individuals. Platelet FALS signal distributions were compared with Coulter resistive particle size distributions by using platelet samples from 12 normal patients and 27 patients with thrombocytopenia. Significant correlation was found between mean FALS and mean resistive particle size (r = 0.83) and between GSD of FALS and GSD of resistive particle size (r = 0.74) with the platelet samples from the 39 subjects studied. These studies, which document the high degree of correspondence among these three independent measurements of platelet size, based on three entirely different principles, strongly suggest that platelet size is log normal distributed and that the GSD value shown above reflects actual heterogeneity in size. The FALS signal distribution was, however, found to be markedly influenced by changes in platelet shape and internal structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1987

Improved in vivo and in vitro viability of platelet concentrates stored for seven days in a platelet additive solution.

An additive solution has been developed for storage of platelet concentrates (PC) which sustains improved in vivo and in vitro viability after 7 d of storage in second generation oxygen permeable containers. This platelet additive solution is a protein-free physiologic salt solution fortified with citrate, bicarbonate and glucose. The in vivo quality of the PC was evaluated by autologous radiolabelling with Indium-111-oxine to measure recovery and survival by multiple hit analysis. The in vitro quality was evaluated by total ATP content, hypotonic shock response and extent of shape change with ADP. Ten paired studies were performed with PC from the same donor being stored for 7 d at 22 degrees C in both CPDA-1 plasma and the additive solution. Mean recoveries and survivals were found to be substantially higher with PC stored in the additive solution than with PC stored in CPDA-1 plasma (51.0 +/- 7.8% and 144.1 +/- 15.9 h versus 36.6 +/- 10.7% and 110.4 +/- 31.6 h). The differences were statistically significant (P less than 0.001). The results of the in vitro assays described above parallelled the in vivo results, with statistically significantly superior results (P less than 0.01) for all parameters of PC stored in the additive solution. This study is the first to show that PC quality may be improved and storage extended using an additive solution.

Adenine↗
PubMed1987

Platelet storage lesion in second-generation containers: correlation with platelet ATP levels.

The nature of platelet lesion occurring with storage of platelet concentrates (PC) in second-generation containers was investigated using various storage media and storage periods up to 14 days. In CPD-plasma (control medium), the changes which occurred progressively during storage were loss of discoid shape, microscopic platelet aggregate formation, fragmentation and the appearance of disintegrated, 'balloon' forms. By day 14 less than 10% of the platelets were discoid in shape, the platelet count had decreased by 23%, and there was a 5-fold increase in the amount of lactate dehydrogenase in plasma. Associated with this was a decrease in the platelet oxygen consumption rate, D(O2), loss of cellular ATP and extent of ADP-induced shape change, and a decrease in the hypotonic shock response. These parameters decreased at a similar rate, with a 50% decrease (t1/2) at days 7-9. They correlated highly with each other during storage and also with a fall in pH. At day 14 of storage, mean pH was 6.1 +/- 0.3. To evaluate the effect of pH stabilization during storage, 4 mEq sodium bicarbonate was added to PC in CPD-plasma. Although pH maintenance was much improved, 7.2-6.6 during 14 days of storage, the same in vitro lesions developed, although more slowly. The t1/2 of the same parameters was prolonged for approximately two days. When PC were stored in a plasma-free physiologic salt solution whose salt composition was similar to CPD-plasma, the t1/2 of the parameters increased to 11-15 days of storage, although the platelets eventually developed the same in vitro lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1987

Familial bleeding disorder associated with deficiencies in platelet signal processing and glycoproteins.

Aggregation responses to low concentrations of ADP, epinephrine, collagen and cationophore A23187 in platelets from two family members with marked bleeding tendencies were virtually absent, whereas shape change with ADP was normal. The contribution to factor X activation by collagen-treated platelets was markedly decreased. Glycoproteins IIb and III were also significantly reduced. The patients' platelets had normal stores of secretable constituents, but secretion of adenine nucleotides and acid hydrolases in response to low concentrations of thrombin and A23187 was drastically reduced compared to normal platelets; secretion of platelet factor 4 was normal. Agonist concentrations that normally produce maximal responses induced only partial aggregation and secretion in the patients' platelets. After prelabelling with [3H]arachidonate thrombin caused less changes in the [3H]phosphatidylinositol, [3H]phosphatidylcholine and free [3H]arachidonate in platelets from the patients than in platelets from normals. We conclude that the patients' platelets have an impairment in part of the signal processing mechanism that is common for all agonists and responses. This platelet abnormality, which has a superficial resemblance to thrombasthenia, represents a hitherto undescribed qualitative platelet disorder.

Adenosine Diphosphate↗
PubMed1986

Morphological changes associated with pH changes during storage of platelet concentrates in first-generation 3-day container.

The platelet injury and loss of viability that has been shown to occur with storage of platelet concentrates (PC) under conditions with increasing or falling pH were examined using scanning and transmission electron microscopy. After storage, samples were taken for measurement of pH value, platelet count and size distribution, release of lactate dehydrogenase (LDH) into plasma, and for SEM and TEM. Increased levels of LDH were observed in PC with pH above 7.3 and below 6.1. In PC with pH above 7.3 this was related to an increased number (23%) of platelets that were lysed or had a swollen disintegrated internal structure (balloons) as seen with TEM. SEM and Coulter counter studies also showed that platelet fragmentation and formation of microvesicles were prominent in PC with pH above 7.3. The electron microscopic pictures confirmed previous suggestions that platelet disc-to-sphere transformation and cytoplasmic swelling occur when pH falls below 6.7-6.8 during storage. SEM studies showed that concomitant with this change, folds and bulky projections appeared on the platelet surface. In PC with pH below 6.1 the morphological change was irreversible with the appearance of more than 90% lysed and balloon platelets. In conclusion, these studies suggest that the loss of viability observed with PC with pH above 7.3 or below 6.1 after storage is related to an increased percentage of lysed and balloon platelets.

Blood Platelets↗
PubMed1986

Morphological changes associated with pH changes during storage of platelet concentrates.

The platelet injury and loss of viability that has been shown to occur with storage of platelet concentrates (PC) under conditions with increasing or falling pH were examined using scanning and transmission electron microscopy. After storage of PC in first (PL-146) and second generation containers (PL-1240 and PL-732), samples were taken for measurement of pH value, platelet count and size distribution, release of lactate dehydrogenase (LDH) into plasma, and for SEM and TEM. After storage of 83 PC in first generation containers for 4 days increased levels of LDH were observed in PC with pH above 7.3 (n = 2) and below 6.1 (n = 4). The electron microscopic pictures confirmed previous suggestions that platelet disc-to-sphere transformation and cytoplasmic swelling occur when pH falls below 6.7-6.8 during storage. In PC with pH below 6.1 the morphological change was irreversible with the appearance of more than 90% lysed and balloon platelets. In PC with pH above 7.3 because of low platelet concentration this was related to an increased number of platelets that were lysed of had a swollen disintegrated internal structure (balloons) as seen with TEM. SEM and Coulter counter studies also showed that platelet fragmentation and formation of microvesicles were prominent in PC with pH above 7.3. Second generation containers maintained the pH during 5-day-storage at higher levels but had enhanced risk of pH increase. A strong tendency for the platelets to become alkaline upon subsequent storage could be demonstrated as a result of excessive forces or prolonged centrifugation during the second spin of the preparation procedure. Whereas the platelet injury caused by low pH is easy to recognize because of the absence of swirling the morphological changes associated with high pH cannot be detected directly.

Acid-Base Equilibrium↗
PubMed1984

Effect of phospholipase C (Bacillus cereus) on freshly isolated and 4-day-stored human platelets.

Phospholipase C (from Bacillus cereus) was used to study fresh and stored human platelets. Provided that the enzyme was inactivated before lipid extraction, no significant degradation of phospholipid in fresh cells was noted, even when platelets were activated or induced to change shape by ADP, collagen or thrombin. With platelets isolated from concentrates stored for transfusion for 4 days at 22 degrees C, membrane phospholipids were degraded by the enzyme to an extent depending on the pH in the platelet concentrate at day 4 of storage. The extent of phospholipid hydrolysis in platelets correlated well with the extent of release of lactate dehydrogenase during storage, with both being minimal for platelets from concentrates of final pH 6.5-6.9. Under non-lytic conditions, phosphatidylcholine was the phospholipid most degraded (40%), with no significant degradation of phosphatidylserine being detected. Storage does not seem to alter the distribution of phospholipids at the external leaflet of the plasma membrane.

Bacillus cereus↗
PubMed1984

The effect of albumin bound polyunsaturated fatty acids on human platelets.

Platelet rich plasma (PRP) was incubated at 22-24 degrees C for 24 hr with various polyunsaturated fatty acids (PUFA), bound to albumin, to determine whether changes in the FA composition of the platelet phospholipids might induce changes in platelet behavior and in platelet structural integrity. The PUFA tested were linoleic (18:2 w6), linoleic (18:3 w3), dihomo-gamma linolenic (20:3 w6), arachidonic (20:4 w6) and eicosapentaenoic acids (20:5 w3). Only PRP incubated with 20:3 w6 and 20:5 w3 incorporated significant amounts of these FA into the platelet phospholipids and showed inhibition of aggregation and TxB2 production with collagen. However, the inhibition was not due to the incorporation of these FA's into the phospholipids as observed by washing and resuspension of the FA incorporated platelets in control plasma, or to any change in structural integrity. It is suggested that the effect of 20:3 w6 and 20:5 w3 on aggregation is due to metabolites of these FA's released from the platelets.

Albumins↗
PubMed1984

Platelet metabolism during storage of platelet concentrates at 22 degrees C.

The development of methods for storing platelet concentrates (PCs) at 22 degrees C for transfusion has been predominantly empiric, with minimal knowledge of metabolic events occurring during storage. It is known that a decrease in pH due to accelerated production of lactic acid in hypoxic conditions is a major cause for loss of platelet viability. In the current studies, we have measured metabolic parameters such as O2 and glucose consumption rates and CO2 and lactic acid production rates. We have also determined the O2 and CO2 transport capacities of various containers and the buffering capacity of plasma. The O2 consumption rate was 1.10 +/- 0.16 (SD) nmol/min/10(9) platelets. In well-oxygenated systems, lactic acid formation was 1.74 +/- 0.12 nmol/min/mL PC for PCs with a platelet count of 1 to 2 X 10(9)/mL; and 0.52 mol of glucose was consumed per 1 mol lactic acid produced. In a completely oxygen-free system, lactic acid production increased 5-8-fold. These calculations suggest that 85% of energy generation is derived through oxidative metabolism and that glucose may not be the primary substrate for this metabolism. Bicarbonate concentration, initially 22.1 +/- 1.6 mEq/L, decreased 1.41 +/- 0.18 nEq/min/mL PC for PCs with counts 1 to 2 X 10(9) platelets/mL. The loss of bicarbonate was caused by displacement by lactic acid and as a consequence of spontaneous CO2 efflux from the container. CO2 production, 2.3 +/- 0.4 nmol/min/10(9) platelets, was derived from oxygen consumption and the CO2 liberated from bicarbonate as it was consumed. A rapid fall in pH to levels below 7.0 (22 degrees C) took place when the bicarbonate concentration fell below 5 mEq/L as lactate concentrations reached 20 to 25 mmol/L. A further increase in lactate concentration from 25 mmol/L to 40 mmol/L correlated with a further fall in pH to 5.8. Thus, the ultimate storage life of a PC is determined by continuous lactate production and the fixed buffering capacity of plasma and by the glucose concentration of the PC. With knowledge of these parameters, methods for predicting pH as a function of time, platelet count, and O2 and CO2 transport capability of the container have been developed as guidelines for future work.

Bicarbonates↗
PubMed1984

Studies of the platelet density abnormality in myeloproliferative disease.

We have previously shown that the extinction (optical density) of normal fresh platelets correlates closely with their apparent volume as determined with the Coulter counter and that platelets from patients with myeloproliferative disorders (MPD) have a decrease in extinction relative to their apparent volume. In this study we show that the reduction in extinction of MPD platelets correlates with a decrease in platelet density and with a decrease in the refractive index of the platelet hyaloplasm. To explore the abnormality of the hyaloplasm, we incubated normal and MPD platelets in plasma from blood anticoagulated with K3-ethylenediaminetetraacetate (EDTA). Normal platelets responded with marked swelling, as shown by an increase in apparent Coulter volume and by corresponding decreases in density, extinction, and refractive index of hyaloplasm. The magnitude of these changes was markedly less with MPD platelets. Ultrastructural studies by others have indicated that the swelling effect of EDTA results from dilatation of intracellular channels such as the surface-connected canalicular system and that these structures occupy more of the interior of MPD platelets than in the case of normal platelets. One hypothesis to explain our findings is that MPD platelets circulate with dilated internal channels that are unable to dilate further with EDTA. In addition, we previously found that MPD platelets display an increased dispersion (geometric standard deviation) of their apparent Coulter volumes. In this study we show that the dispersion abnormality correlates with the density abnormality and that the increase in dispersion is not confined to a subpopulation of abnormal light platelets; rather, it is present in all density subpopulations. All of our data are consistent with the view that the abnormalities in density and dispersion originate at the time of shedding from the megakaryocyte.

Blood Platelets↗
PubMed1983

Effect of intravenous carbenicillin, cefoxitin and cefamandole on ADP-induced platelet aggregation and shape change.

The effect of a large daily dose of i.v. carbenicillin, cefoxitin and cefamandole on platelet aggregation with adenosine diphosphate (ADP) and the effect of carbenicillin on ADP induced shape change were evaluated. Six volunteers received carbenicillin 100 mg/kg every 4 hours. Three of them also received cefoxitin 3 gm every 6 hours and cefamandole 2 gm every 4 hours. All treatments were separated by 14 days. Prior to treatment, as well as 1 and 24 hours after the last dose of antibiotic, citrated platelet-rich plasma was tested for the extent of aggregation at a series of ADP concentrations. As previously reported by several groups, carbenicillin decreased the sensitivity of platelets in their aggregation response to ADP. Thus, the concentration of ADP needed to obtain 50% of maximal aggregation response was increased 3.5 +/- 1.7 (S.D.) fold. In addition, when measured separately, the sensitivity of platelets in their shape change response to ADP was decreased to a similar degree. The concentration of ADP needed to produce 50% of maximal shape change response was 2.8 +/- 1.6 (S.D.) fold higher after carbenicillin treatment. The results are in accordance with previous in vitro studies suggesting that carbenicillin interferes with the initial phase of platelet activation. Cefoxitin and cefamandole had no apparent effect on platelet aggregation.

Adenosine Diphosphate↗
PubMed1983

Platelets and coagulation in patients with familial hypercholesterolemia (type IIa).

Seventeen subjects with hypercholesterolemia (type IIa) were compared with 11 normocholesterolemic family members (controls) with similar dietary habits. The type IIa subjects had a shorter bleeding time. Beta-thromboglobulin in plasma and thromboxane B2 and malondialdehyde released from platelets before and after stimulation with collagen or thrombin were similar. No differences in platelet sensitivity to adenosine diphosphate, thrombin or collagen were observed. Gel-filtered platelets from type IIa subjects had a tendency to spontaneous aggregation and lower procoagulant activity. Platelet sensitivity to prostacyclin was slightly higher in type IIa subjects. No differences in a series of coagulation parameters were observed between the groups. This study has shown some deviations from normal in platelets from subjects with familial hypercholesterolemia. These changes may contribute to the increased tendency to occlusive vascular diseases in such subjects.

Adult↗
PubMed1983

Effects of cod liver oil on platelets and coagulation in familial hypercholesterolemia (type IIa).

Patients with familial hypercholesterolemia (type IIa) were given 30 ml cod liver oil (CLO) as dietary supplement daily for 6 weeks. The effects on platelets, bleeding time, coagulation and blood and platelet lipids were examined. The major findings were a reduced collagen-induced platelet aggregation and a decrease in thrombin-stimulated thromboxane B2 generation in platelets in vitro. The primary bleeding time was not significantly prolonged. Statistically significant increase in eicosapentaenoic acid/arachidonic acid ratios in the main platelet phospholipids were also observed. These changes did not correlate with any of the changes in platelet behavior observed after CLO intake. The serum total and HDL cholesterol and triglycerides were not altered during the trial.

Adult↗
PubMed1983

Platelet storage at 22 degrees C for transfusion: interrelationship of platelet density and size, medium pH, and viability after in vivo infusion.

Previous studies have suggested that there are two characteristic storage lesions that develop during storage of PC at 22 degrees C with constant agitation in containers constructed from PVC plastic. One occurs only in PC with high platelet count in which there is a fall in pH due to hypoxic conditions within the container. This storage lesion is characterized by an increase in apparent mean volume as determined by Coulter Counter and a change in platelet shape from disc to sphere. The other is observed in PC with low platelet counts; in these, a major pH fall does not occur. Under these conditions, there is a decrease in the apparent mean volume and an increase in the dispersion of the size distribution determined by Coulter Counter. The cause of this storage lesion is uncertain. However, it appears to be more pronounced with some forms of agitation than with others. In the current studies, we have attempted to clarify further the nature of these two storage lesions. We now show that during fall in pH of PC to levels below 6.8, the increase in apparent platelet volume corresponds well with a decrease in platelet density and refractive index, both consistent with cellular swelling due to influx of extracellular fluid. We were previously unable to determine whether this lesion was due to pH fall per se or to the associated hypoxic conditions. In the current study, platelets stored under a nitrogen atmosphere for as long as 7 days show no swelling or shape change when the pH is kept above 6.8, suggesting that the damage is due to pH fall per se. In previous studies of the second storage lesion, which occurs without pH fall, we have found that the increase of the dispersion of the Coulter volume distribution correlates with loss of in vivo viability measured as percent recovery after labelling with chromium-51. In this study, we show that the increase in dispersion results from the presence of a population of abnormally light platelets. Since this light population labels normally with chromium-51, we hypothesize that it contains the cells which fail to circulate after in vivo infusion. In three infusions of thrombocytopenic patients, we support this hypothesis by showing that the abnormal light population does not circulate in vivo and that the dispersion of the apparent volume distribution of the circulating cells is normal.

Blood Platelets↗