A new enzyme-linked immunosorbent assay recognizing both rat and human activated coagulation Factor XII (FXIIa)

Papageorgiou, Peter C.; Yeo, Erik; Backx, Peter H.; Floras, John S.

doi:10.1016/j.jim.2012.01.002

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Assuming that a rat has ~15 ml of blood containing ~40 μg/ml of FXII zymogen [ 20 ] (600 μg for a 300 g rat), the total dose of β-FXIIa infused over 60 min (5.1 μg/kg of body weight; 1.53 μg for a 300 g rat), which represents ~0.26% of its total FXII zymogen, can be considered to lie well within its physiological range. Alternatively, based on the Beer–Lambert law, where concentration is proportional to absorbance, the circulating FXIIa levels (0.86±0.05 A 550 units) were approximately <0.63% of the total FXII zymogen content (1.37±0.09 A 550 units; RAT a diluted 1:100) [ 21 ].…”

Section: Methodsmentioning

confidence: 99%

“…Plasma was separated and stored at −80°C in approximately 100 μl aliquots for analysis. Plasma β-FXIIa was measured using a novel FXIIa ELISA that employs mAb (monoclonal antibody) 201/9 which binds to conformational epitopes on the heavy chain of β-FXIIa and exhibits no cross-reactivity with FXII zymogen or FXIIa–inhibitor complexes [ 21 ]. Adrenaline and noradrenaline concentrations were determined using HPLC with electrochemical detection [ 22 ].…”

Section: Methodsmentioning

confidence: 99%

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Activated plasma coagulation β-Factor XII-induced vasoconstriction in rats

et al. 2012

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By inducing BK (bradykinin)-stimulated adrenomedullary catecholamine release, bolus injection of the β-fragment of activated plasma coagulation Factor XII (β-FXIIa) transiently elevates BP (blood pressure) and HR (heart rate) of anaesthetized, vagotomized, ganglion-blocked, captopril-treated bioassay rats. We hypothesized that intravenous infusion of β-FXIIa into intact untreated rats would elicit a qualitatively similar vasoconstrictor response. BN (Brown Norway) rats received for 60 min either: (i) saline (control; n=10); (ii) β-FXIIa (85 ng/min per kg of body weight; n=9); or (iii) β-FXIIa after 2ADX (bilateral adrenalectomy; n=9). LV (left ventricular) volume and aortic BP were recorded before (30 min baseline), during (60 min) and after (30 min recovery) the infusion. TPR (total peripheral resistance) was derived from MAP (mean arterial pressure), SV (stroke volume) and HR. Saline had no haemodynamic effects. β-FXIIa infusion increased its plasma concentration 3-fold in both groups. In adrenally intact rats, β-FXIIa infusion increased MAP by 6% (5±2 mmHg) and TPR by 45% (0.50±0.12 mmHg/ml per min), despite falls in SV (−38±8 μl) and HR [−18±5 b.p.m. (beats/min)] (all P<0.05). In 2ADX rats, β-FXIIa had no HR effect, but decreased SV (−89±9 μl) and MAP (−4±1 mmHg), and increased TPR by 66% (0.59±0.15 mmHg/ml per min) (all P<0.05). After infusion, adrenally intact rats exhibited persistent vasoconstriction (MAP, 10±1 mmHg; TPR, 0.55±0.07 mmHg/ml per min; both P<0.05), whereas in 2ADX rats, MAP remained 5±1 mmHg below baseline (P<0.05) and TPR returned to baseline. End-study arterial adrenaline (epinephrine) concentrations in the three groups were 1.9±0.6, 9.8±4.1 and 0.6±0.2 nmol/l respectively. Thus, in neurally intact lightly anaesthetized untreated rats, β-FXIIa infusion induces both adrenal catecholamine-mediated and adrenally independent increases in peripheral resistance.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Activated plasma coagulation β-Factor XII-induced vasoconstriction in rats

et al. 2012

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“…From these values SV, CO and TPR were derived, as previously described [9]. Subsequently, blood ($500 ml) was collected for FXIIa analysis using a rat ELISA without cross-reactivity with FXII zymogen or FXIIa:inhibitor complexes [24]. A second ($500 ml) sample was collected for plasma epinephrine (E) and norepinephrine (NE) determination [25].…”

Section: Experimental Designmentioning

confidence: 99%