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PubMed1986

Oscillating platelet counts in healthy individuals: experimental investigation and quantitative evaluation of thrombocytopoietic feedback control.

Peripheral platelet counts of 5 healthy women and 5 healthy men were studied over 54 to 100 d to assess whether statistically significant fluctuations could be detected. Low amplitude fluctuations were found in 7 of the 10 individuals with mean periods of 28.3 +/- 3.4 d, using autocorrelation analysis. To understand the origin of such fluctuations, a simple linear feedback model of thrombocytopoiesis was formulated and quantitatively analyzed. This model, together with literature data on platelet-turnover in healthy individuals and patients with idiopathic thrombocytopenic purpura (ITP), predicts states in which oscillations are likely to occur and explains these as a result of optimum tuning of the feedback system to respond quickly to disturbances in the platelet pool. Both in healthy individuals and patients with cyclic thrombocytopenia, the typical periods of the fluctuations predicted by the model of about 25 d are in good agreement with the data.

Adult↗

PubMed1983

A comparison of platelet count and acute phase proteins in the measurement of disease activity in rheumatoid arthritis.

Platelet count (PC) was compared with standard acute phase reactants (ESR, plasma viscosity and C-reactive protein) and clinical measurements to assess its usefulness as a measure of disease activity in 165 patients with active rheumatoid arthritis. Although PC was elevated (greater than 400 X 10(9) 1(-1) in 45% of patients and was seen to fall under the influence of second-line drugs, it was considered to be unsuitable as an indication of disease activity since levels fall for reasons other than disease improvement.

Anti-Inflammatory Agents↗

PubMed2005

[Effects of local carbon ion irradiation on survival and peripheral blood leukocyte and platelet counts of tumor-bearing mice].

OBJECTIVE: To investigate the effects of local carbon ion irradiation on the length of survival and peripheral blood leukocyte and platelet counts of mice inoculated with pulmonary tumor cells. METHODS: Thirty tumor-bearing mice were randomly divided into control group (tumor-bearing but without carbon ion irradiation, n=10), 12 Gy group (n=10) and 24 Gy group (n=10). The right hind limbs of the mice, where the tumor cells were inoculated, were irradiated with carbon-ion beams at a single dose in 12 Gy and 24 Gy groups, and those of the control group received no irradiation. The peripheral blood leukocytes and platelets of the mice in all the 3 groups were counted immediately before and 7 and 14 days after irradiation, respectively, with the survival time of the mice recorded. RESULTS: There was no significant difference in the survival time of the mice between the 3 groups. The peripheral blood leukocyte counts in all groups increased after irradiation, no significant difference was noted between the two irradiation the groups and the control group. Irradiation at 24 Gy resulted in significant increase in peripheral blood platelet count on the 14th day (P=0.032, F=4.062), but no such increment was observed in the other 2 groups or on day 7 in the 24 Gy group. CONCLUSION: Local carbon ion irradiation may not produce significant effects on the length of survival and hemogram of the tumor-bearing mice.

Animals↗

PubMed2006

[Hemolysis, elevated liver enzymes, and low platelet count syndrome].

HELLP (hemolysis, elevated liver enzymes, and low platelet count) syndrome is a severe, life-threatening pregnancy pathology, which occurs in 0.2-0.8% of all pregnancies, and approximately 10% (2-20%) of pregnancies are complicated with severe preeclampsia. This syndrome usually develops in the third trimester of pregnancy in preeclamptic patients, sometimes it occurs in the second trimester of pregnancy, and very rarely HELLP syndrome may develop within 48-72 hours after delivery. Diagnosis is complicated as there are no specific clinical signs, therefore, this syndrome may be confused with other pathologies like acute fatty liver of pregnancy, idiopathic thrombocytopenia, hemolytic uremic syndrome, appendicitis, and etc. The patients with HELLP syndrome should be treated in the tertiary care hospital, where appropriate diagnostics and multidisciplinary help for mother and fetus can be assured. When the syndrome was described for the first time, L. Weinstein recommended prompt delivery as the only possible treatment. Current studies show that conservative treatment of patients with HELLP syndrome is safe, without an increase in morbidity and mortality. That is why now many authors agree that treatment approach should be based on the estimated gestational age and the condition of the mother and fetus.

Adult↗

PubMed2006

Utility of a whole blood single platelet counting assay to monitor the effects of tirofiban in patients with acute coronary syndromes scheduled for coronary intervention.

This study aimed to establish the utility of a whole-blood single-platelet counting (WBSPC) assay, a measure of microaggregation, in monitoring the effects of tirofiban, comparing this with optical aggregometry (OA) and the Ultegra TRAP cartridge system (UTC), measures of macroaggregation. Fifty-nine patients with acute coronary syndrome scheduled for coronary angiography +/- angioplasty were studied. WBSPC assay (ADP 0.3-100 microM, Sysmex KX21 analyzer), OA (ADP 20 microM) and UTC were performed: before starting tirofiban; 30 min, 4 and 24 h after starting tirofiban; and 1 and 2 h after stopping tirofiban. Thirty minutes after starting tirofiban, there was substantial inhibition of platelet aggregation (40 +/- 30%; WBSPC, 2 minutes after addition of ADP 30 microM) and this remained stable at 4 and 24 h. OA (86 +/- 17%; inhibition of maximal aggregation, ADP 20 microM) and UTC (93 +/- 7%) showed marked inhibition with less inter-individual variation. There was no significant correlation between OA and UTC results (R(2) = 0.006), but fair correlation between OA and WBSPC results (R(2) = 0.37). Greater inhibition of macroaggregation (OA and UTC) was seen compared to microaggregation (WBSPC) such that WBSPC was more discriminating in the therapeutic range when macroaggregation was often completely inhibited. A WBSPC assay of platelet microaggregation shows promise for monitoring GPIIb/IIIa antagonists.

Acute Disease↗

PubMed2005

Serum albumin and platelet count but not portal pressure are predictive of death in patients with Child-Pugh A hepatitis C virus-related cirrhosis.

AIM: The presence of esophageal varices has been reported to be a prognostic factor in patients with compensated hepatitis viral C induced cirrhosis. We studied the prognostic value of hepatic venous pressure gradient in addition to epidemiological and clinical parameters in these patients. METHODS: Among patients with Child-Pugh A hepatitis C induced cirrhosis, prospectively followed in two Parisian centres, 100 had measurement of occluded and free hepatic venous pressures. We evaluated hepatic venous pressures as a predictive factor of death by Cox models (survival) and Fine and Gray models (liver-deaths). RESULTS: Median hepatic occluded pressure and gradient were 21.5 (15-24) and 13 mm Hg (9-15), respectively. The median duration of follow-up was 85 months (range: 70-112); 38 deaths or liver transplantation were registered. Hepatic venous pressure gradient was not significantly related to survival in the studied population but as a continuous variable was predictive of death from liver disease. On multivariable analysis serum albumin <40 g/L and platelet count <90,000 /mm(3) were the only selected prognostic factors. CONCLUSION: Hepatic venous pressure gradient has a limited value for assessing the prognosis of patients with Child-Pugh A hepatitis C virus induced cirrhosis; prognosis is accurately predicted by serum albumin and platelet count.

Aged↗

PubMed1997

Age and platelet count: a simple index for predicting the presence of histological lesions in patients with antibodies to hepatitis C virus. METAVIR and CLINIVIR Cooperative Study Groups.

The aim of this study was to identify clinical and biological factors associated with histological lesions in patients with chronic hepatitis C and to construct a simple diagnostic index. A database consisting of 500 patients with untreated biopsy-proven chronic non-A non-B hepatitis was used. Liver biopsies were reviewed, blind, by a panel of pathologists. Patients were classified according to the presence of necroinflammatory lesions (histological activity) and fibrosis. The diagnostic value of nine clinical and 10 biological factors was assessed using logistic regression analysis, sensitivity, specificity and predictive values, and a score was constructed combining the most significant factors identified. The validation used an independent population of 120 patients. Serum platelet concentration and age were the two main factors significantly and independently correlated with the presence of fibrosis and/or histological activity. A simple score referred to as AP, combining age and platelet count, varied from 0-10. For the presence of significant histological disease (moderate to severe necroinflammatory lesions and/or septal fibrosis to cirrhosis), an AP score of 6 or more had a specificity of 0.93 and a sensitivity of 0.52%. In the validation population, the area under the curve was 0.690 +/- 0.085, not significantly different from that of the first population, 0.763 +/- 0.043. Hence, a simple score combining age and platelet count enabled the accurate prediction of the presence of activity and fibrosis in patients infected with the hepatitis C virus. When this score reached 6, liver biopsy could be avoided owing to its high predictive value. However, the negative predictive value was not high enough to prevent a liver biopsy in patients with a lower score.

Adult↗

PubMed1986

The effect of serial therapeutic plasmapheresis on platelet count, coagulation factors, plasma immunoglobulin, and complement levels.

One hundred therapeutic plasmaphereses were carried out at biweekly intervals in seven patients, without morbidity or mortality, using the IBM 2997 blood fraction separator. In standardised procedures, 1.5 times the calculated plasma volume was replaced with an electrolyte solution containing 4% salt-free human albumin. Anticoagulation was achieved using a whole venous blood to acid-citrate dextrose ratio of 11 to 1. Median flow rates, plasma collection, and procedure times were respectively 40 ml/minute, 20 ml/minute, and 3 hours. Haemoglobin and total white cell counts were not significantly affected by the procedures. In contrast, platelet count, fibrinogen, immunoglobulin levels, total haemolytic complement, as well as C3 and C4 fractions fell, and the prothrombin and partial thromboplastin times were lengthened by the exchanges. All these measurements had returned to normal within 24 hours, apart from the fibrinogen, which took between 48 and 72 hours, and the immunoglobulin level, which required 35 days to return to baseline. In a further patient, more detailed studies (n = 13) were carried out to characterise the behaviour of antithrombin III and factor VIII. Both levels were markedly reduced immediately following the procedure and, like fibrinogen, had returned to normal within 48 hours. These data indicate that in an isovolemic plasmapheresis there was a transient but rapidly reversible effect on all the factors studied, with fibrinogen level, antithrombin III, and factor VIII returning more slowly to normal than the others, and immunoglobulin levels responding the slowest. None of these changes was associated with clinically significant haemostatic abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗

PubMed1984

Effects of Escherichia coli endotoxin on leukocyte and platelet counts, fibrinogen concentrations, and blood clotting in colostrum-fed and colostrum-deficient neonatal calves.

Effects of a single IV injection of Escherichia coli endotoxin on hemogram and clotting function were compared in colostrum-fed and colostrum-deficient neonatal calves. Before endotoxin administration, the 2 groups of calves only differed in their prothrombin times. After endotoxin administration, there were significant differences (P less than 0.005) between colostrum-fed and colostrum-deficient calves in total leukocyte, segmented neutrophil, nonsegmented neutrophil, and lymphocyte (P less than 0.05) counts and partial thromboplastin time. Significant time dependent changes were observed in the aforementioned parameters and in platelet count and fibrinogen concentration. Seemingly, colostrum feeding improved the calf's ability to respond to endotoxin challenge exposure probably because of improved granulopoietic activity.

Animals↗

PubMed1989

Coulter S Plus STKR histograms detect spurious elevation of leucocyte and platelet counts associated with cryoglobulinaemia.

Abnormalities in the size frequency histogram generated by the Coulter S Plus STKR at room temperature raised the possibility of the presence of a cryoglobulinaemia in a man admitted to the hospital with pneumonia. The leucocyte and platelet counts generated by the Coulter S Plus STKR were higher when counts were done at room temperature than counts done at 37 degrees C. Further investigation of the patient revealed the presence of Non-Hodgkin's Lymphoma which had not been suspected on clinical grounds. The importance of testing samples at 37 degrees C, where an abnormality in the Coulter S Plus STKR histogram has been detected at room temperature, is emphasized.

Aged↗

PubMed2000

Blunted rise in platelet count in critically ill patients is associated with worse outcome.

OBJECTIVE: To test the hypothesis that a low rate of change of platelet counts (PCs) after admission to the intensive care unit (ICU) is associated with mortality. Low PCs are known to be associated with disease severity in critically ill patients, but the relevance of time-dependent changes of PCs has not been investigated. DESIGN: Retrospective study. SETTING: A 12-bed surgical ICU of a university hospital. PATIENTS: All adult patients admitted to the ICU for at least 4 days during a 7-yr period. INTERVENTIONS: At admission, Acute Physiology and Chronic Health Evaluation scores were calculated. PCs and leukocyte counts were analyzed from admission to day 10. The daily rise of the PCs (deltaPC/deltat from day 2 to day 10 was calculated. Rates for 30-day mortality as well as hospital mortality were determined. MEASUREMENTS AND MAIN RESULTS: A total of 1,415 admissions were studied. Median PCs (interquartile range) initially decreased and subsequently increased, with a higher PC in 1,203 survivors than in 212 nonsurvivors from day 2 onward (302 [range,181-438] x 10(3)/mm3/day vs. 129 [range, 62-228] x 10(3)/mm3 at day 10; p < 0.001). After stratification of patients per type of surgery, within each group PC was also higher in survivors. Mean deltaPC/deltat was more than five times higher in survivors compared with nonsurvivors: 30 +/- 46 x 10(3)/mm3/day vs. 6 +/- 28 x 10(3)/mm3/day (p < 0.001). The area under the receiving operating characteristic curve of deltaPC/deltat for 30-day survival was 0.743 compared with 0.728 for the Acute Physiology and Chronic Health Evaluation. Leukocyte counts showed marginal differences between nonsurvivors and survivors. CONCLUSION: A blunted or absent rise in PCs in critically ill patients is associated with increased mortality. deltaPC/deltat is a readily available and simple parameter to improve assessment of critically ill patients.

APACHE↗

PubMed1987

Correlative patterns of neutrophil and platelet counts during very early remission of acute myeloblastic leukemia.

Patterns of recovery for peripheral blood neutrophils and platelets were analyzed in 65 patients with acute myeloblastic leukemia (AML) undergoing their first course of induction chemotherapy. Specifically, for every patient linear correlation coefficients (r values) were computed for neutrophils versus platelet counts every three days from Day 12 to 27 of therapy. Correlations were designated as "significant" if r greater than or equal to 0.82 (p less than or equal to 0.05). Patients who would enter complete remission with the first course of therapy were significantly more likely to have significant neutrophil-platelet correlations in the recovery phase than patients who did not achieve remission with the first course or who would have resistant disease (76% versus 20% and 76% versus 15%, respectively, both p less than 0.001). Although these data are preliminary and retrospective they nonetheless demonstrate a trend that may prove useful for patient monitoring if proven correct by formal studies. A prospective investigation examining neutrophil and platelet correlations within a defined period of early hematologic recovery is indicated to assess if such parameters have early prognostic value for the prediction of remission in individual patients receiving induction therapy for AML.

Bone Marrow↗

PubMed1975

On the "easy bruising" syndrome with normal platelet count. A study of 75 patients.

Seventy-five consecutive patients with normal platelet counts were investigated for "easy bruising." All had a normal coagulation profile, and all except four were women. None were on aspirin or other antiplatelet agents. Two specific groups could be delineated. In type I (44 patients, mean age, 35), platelet function was normal to supranormal. Megathrombocyte number was elevated in 60% of patients and correlated with the presence of antiplatelet antibody in 30% of patients. In type II (31 patients, mean age, 34), platelet function was abnormal: impaired epinephrine aggregation (primary and secondary wave) in 97%, impaired connective tissue aggregation in 77%, and impaired ADP aggregation in 42%. Megathrombocyte number was elevated in 71%, and antiplatelet antibody was present in 38% of patients. The "easy bruising" syndrome can be differentiated into two categories: type I, in which a platelet abnormality is unlikely, and type II, in which a platelet abnormality exists. Elevated incidence of antiplatelet antibody in both groups suggests a possible autoimmune cause.

Adenosine Diphosphate↗

PubMed1993

Platelet counts in thalassemic children before and after splenectomy.

Even though thrombotic risks in thalassemia patients from standpoints of platelet dysfunction and coagulation factors are controversial, they are in favor of thrombosis due to thrombocytosis. From the study of 74 cases of thalassemia in children, marked thrombocytosis occurred during day 8 to 4 months during which one should be aware of the thrombosis. However, none of thalassemia children had acute thrombosis even at platelet counts of 1.6 million/microliters.

Blood Platelets↗

PubMed1990

Electrochemical treatment of cancer. IV: Leukocyte and platelet counts in peripheral blood after electrochemical treatment of solitary lung neoplasms.

The effects on hematological parameters in peripheral blood was measured by electronic cell counting after electrochemical treatment (n = 11), after electrochemical treatment with concomitant intraneoplastic injection of the chemotherapeutic agent doxorubicin (Adriamycin) (n = 13), and after electrochemical treatment with concomitant intravenous infusion of Adriamycin (n = 2). After treatment, a reduction in lymphocyte count (p less than 0.01) and an increase in total leukocyte count (p less than 0.01) was observed. There was a trend that during treatment the platelet count was reduced.

Adult↗

PubMed1993

Neurological state, infarct size and clinical outcome are related to early platelet count decrease in stroke.

We performed this study in order to verify the existence of a correlation between early platelet count reduction and initial neurological impairment, infarct extension and mortality or clinical outcome in an established ischemic cerebral infarction. The results demonstrate that the platelet consumption and/or accumulation in the infarct area, expressed by circulating platelet decrease, is related to the severity of neurological involvement, infarct size and poor clinical outcome.

Aged↗

PubMed1990

Enhanced anaphylatoxin and terminal C5b-9 complement complex formation in patients with the syndrome of hemolysis, elevated liver enzymes, and low platelet count.

Complement activation was studied in ten consecutive pregnant women developing hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) and ten other women with normal pregnancies. Blood samples for anaphylatoxin (C3a/C3a desArg and C5a/C5a desArg) and terminal C5b-9 complement complex determinations were drawn at delivery and 24 hours and 7 days later. Women developing HELLP syndrome had higher plasma levels of anaphylatoxins with delivery than did women with uneventful pregnancies. The plasma levels of terminal C5b-9 complement complexes at the time of delivery were increased as compared with levels 1 and 7 days after delivery in women with HELLP syndrome. The plasma concentrations of the anaphylatoxins and the terminal C5b-9 complement complexes returned to normal levels within 1 week after delivery in the HELLP group. The formation of C5b-9 complement complex indicates that the terminal part of the complement cascade has been activated and that C5a has been formed and eliminated. Complement activation with release of anaphylatoxins and terminal C5b-9 complement complexes may be one etiologic factor behind the elevated blood pressure, hemolysis, liver insufficiency, and platelet consumption seen in these patients.

Adult↗

PubMed2003

von Willebrand factor and platelet count in ruptured abdominal aortic aneurysm repair.

OBJECTIVE: von Willebrand factor (vWF) is essential for the formation of platelet aggregates at sites of vascular endothelial cell (EC) injury. Peri-operative thrombocytopenia is associated with poor outcome in ruptured abdominal aortic aneurysm (AAA) repair. This prospective study examines the relationship between vWF and platelet count (PC) in ruptured AAA repair. METHODS: plasma vWF antigen, PC and C-reactive protein (CRP) were measured pre-operatively, and immediately before and 5 min after aortic clamp release, and on post-operative days 1 and 2 in 20 patients (18 men and 2 women of median age 74, range 63-86, years) with ruptured AAA. RESULTS: elevated vWF was present in 13 (65%) patients pre-operatively, and 14 of 16 (88%) survivors at 24 h post-operatively. All patients demonstrated an intra-operative fall in vWF. There was no significant difference in vWF levels between survivors and non-survivors. PC was below the normal range in 8 (40%) patients pre-operatively and all patients at 24 h. Eighteen (90%) patients demonstrated an intro-operative fall in PC. PC was significantly lower in non-survivors pre-operatively (p=0.007), immediately before (p=0.009) and 5 min (p=0.009) and 24 h (p=0.02) after clamp release. There was a significant positive correlation between vWF and PC pre-operatively (r= +0.48, p=0.033), and immediately before (r= +0.47, p=0.044) and 5 min after clamp release (r= +0.5, p=0.043). There was a significant positive correlation between peak vWF level and the greatest fall in PC (r= +0.65, p=0.006). There was a significant negative correlation between vWF and CRP and operative blood loss; and between PC and CRP, operative blood loss and aortic clamp time. CONCLUSIONS: these data demonstrate that EC activation, the acute phase protein response, operative blood loss and aortic clamp time all contribute to the peri-operative fall in PC in patients with ruptured AAA. The peri-operative fall in circulating levels of vWF and PC may represent consumption secondary to macro- and microvascular thrombus formation. The resultant procoagulant state may partly explain the association between low PC and poor outcome in ruptured AAA.

Aged↗