The Pathogenesis of Purpura Hemorrhagica With Especial Reference to the Part Played by Blood-Platelets

Abnormal Platelet Functions in β Thalassaemia

“…The following examinations were performed on all patients: complete blood count, platelet count (Brecher & Cronkite 1950), bleeding time (Duke 1912) and clot retraction (MacFarlane 1939). Platelet factor 111 availability was determined in 6 T. maj. patients according t o the method of Hardisty & Hutton (1965).…”

Bleeding Time Tables

“…BT > 20m by both methods 2) vW factor and factor VIII/vW factor do not correlate with BT, evidence of clinical bleeding, BUN, or creatinine prolonged BT and low platelet counts compared to term and preterm infants 1) median 9.5m (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14] 2) weak correlation between BT and aggregating ability of collagen from these patients mean BT increased 1) mean BT longer in females in all subgroups 2) BT longer in younger controls (not statistically significant)…”

“…3) "'grey' zone" to 10m upper limit of 7m stresses need for using average of multiple determinations 104/145 comparisons agreed within 0.5m 26 4 Duke, 13 Ivy, 27 Macfarlane (Ivy); duplicate readings separated in time (Ivy) and near in time (Duke and Macfarlane); no mention of screening for aspirin ingestion; population consisted of normal volunteers and some patients with purely local lesions, to examine the effects of bed rest; red haired people especially recruited; ANOVA of results healthy volunteers studied in Amsterdam (3) and Utrecht (3); platelet count and aggregation studies standardized longitudinal or transverse incision with automatic lancet; wound then covered with sterile transparent plastic cube, with 25° C water flowing through it; rate and time of bleeding observed group 1: normal volunteers; group 2: rubber industry workers during routine medical visit normal volunteers; measured once in each arm studies in 2 centers (Amsterdam, Utrecht) of 40 subjects each (sex ratio 1:1); BT before and 24h after 20 mg/kg ASA; multiple other platelet function studies well subjects; made incision using both lancet and automatic plunger in each subject; looked at Duke (blotting every 30s), Ivy (blotting every 30s), Ivy (blotting every 15s), and automated method (30 subjects in each of these 4 studies); also did correlation between duplicate readings in 90 individuals, dividing them into 3 chronological groups of 30 each normal subjects; 4 tests each over several weeks 1) systematic difference between operators 2) correlation between ears 3) σ declines until age 40-60, then climbs (similar to pattern of BT itself) 4) correlation between BT and σ Ivy: 1) longer BT than in Ivy study, presumed due to deeper cut 2) significant temporal variability within individuals 3) significant constitutional differences in BT between individuals 4) no evidence of connection of constitutional differences with age, hair color, physical constitution, or skin thickness, elasticity or temperature Macfarlane: similar to Ivy…”

Vitamin K-reversible hypoprothrombinemia in rats. I. Sex differences in the development of hypoprothrombinemia and the effects of beta-lactam antibiotics.

“…Animals in the control group were given physiological saline at 3.6 ml/kg/day, intravenously. The bleeding time of these animals was determined ac cording to the method of Duke (14). At the end of the experiments, the animals were placed under ether anesthesia, and blood samples were withdrawn from the vena cava with a disposable syringe containing 1/10 volume of 3.8% sodium citrate solution.…”