Comparability of serum and plasma concentrations of haemostasis activation markers.

Since serum and plasma D-dimer concentrations correlate very well, we evaluated the comparability of other haemostasis activation markers in plasma and serum. Prothrombin fragment F1+2, fibrin monomer and D-dimer concentrations were measured with commercially available immunoassays in serum and plasma. Serum to plasma ratios were evaluated to determine the direct (prothrombin fragment F1+2) and indirect (fibrin monomer, D-dimer) downstream influence of prothrombinase on the serum to plasma comparability. Prothrombin fragment F1+2 serum and plasma concentrations did not correlate (R2 = 0.09, ns), while an unexpected high degree of correlation was found for fibrin monomer (R2 = 0.66, p < 0.001), and, as expected, a very good correlation was found for D-dimer (R2 = 0.94, p < 0.001). Median serum to plasma ratios decreased from prothrombin fragment F1+2 (16.26) to fibrin monomer (2.24, p < 0.001) and D-dimer (1.00, p < 0.001), following a highly linear relationship (R2 = 0.93) Plasma and serum concentrations of the evaluated markers correlate the better the farther from prothrombinase activity the respective marker is generated. Serum is not suitable for prothrombin fragment F1+2 measurements, whereas fibrin monomer serum concentrations seem of value for research applications. With the used assay, serum seems an appropriate matrix for clinical D-dimer measurements. This would considerably simplify testing strategies. Validation in further clinical trials is needed.     

Thrombin generation during cardiopulmonary bypass: the possible role of retransfusion of blood aspirated from the surgical field

BACKGROUND: In spite of using heparin-coated extracorporeal circuits, cardiopulmonary bypass (CPB) is still associated with an extensive thrombin generation, which is only partially suppressed by the use of high dosages of heparin. Recent studies have focused on the origins of this thrombotic stimulus and the possible role of retransfused suctioned blood from the thoracic cavities on the activation of the extrinsic coagulation pathway. The present study was designed to find during CPB an association between retransfusion of suctioned blood from the pericardium and pleural space, containing activated factor VIIa and systemic thrombin generation. METHODS: Blood samples taken from 12 consenting patients who had elective cardiac surgery were assayed for plasma factor VIIa, prothrombin fragment 1+2 (F1+2), and thrombin-antithrombin (TAT) concentrations. Blood aspirated from the pericardium and pleural space was collected separately, assayed for F1+2, TAT, and factor VIIa and retransfused to the patient after the aorta occlusion. RESULTS: After systemic heparinization and during CPB thrombin generation was minimal, as indicated by the lower than base line plasma levels of F1+2, and TAT after correction for hemodilution. In contrast, blood aspirated from the thoracic cavities had significantly higher levels of factor VIIa, F1+2, and TAT compared to the simultaneous samples from the blood circulation (P < 0.05). Furthermore, after retransfusion of the suctioned blood (range, 200-1600 mL) circulating levels of F1+2, and TAT rose significantly from 1.6 to 2.9 nmol/L (P = 0.002) and from 5.1 to 37.5 μg/L (P = 0.01), respectively. The increase in both F1+2, and TAT levels correlated significantly with the amount of retransfused suctioned blood (r = 0.68, P = 0.021 and r = 0.90, P = 0.001, respectively). However, the circulating factor VIIa levels did not correlate with TAT and F1+2 levels. CONCLUSIONS: These data suggest that blood aspirated from the thoracic cavities during CPB is highly thrombogenic. Retransfusion of this blood may, therefore, promote further systemic thrombin generation during CPB.     

正常妊娠妇女血中活化的蛋白C抵抗、狼疮样抗凝物质与血栓前状态分子标志物测定

目的研究活化的蛋白 Ｃ抵抗（Ａｃｔｉｖａｔｅｄ ｐｒｏｔｅｉｎ Ｃ ｒｅｓｉｓｔａｎｃｅ，ＡＰＧＲ）在正常妊娠中的发生情况，探讨狼疮抗凝物质（Ｌｕ－ｐｕｓ－ｌｉｋｅ ａｎｔｉｃｏａｇｕｌａｎｔ，ＬＡ）对妊娠性 ＡＰＣ－Ｒ的影响及二者与凝血酶生成、继发性纤溶的关系。方法采用 ＡＰＴＴ－ＡＰＣ法检测ＡＰＣ－Ｒ、ｄＲＶＶＴ法测定ＬＡ水平，并用 ＥＬＩＳＡ法测定了凝血酶原片段Ｆ１＋２和Ｄ－二聚体（Ｄ－ｄｉｍｅｒ，Ｄ－Ｄ）的含量。结果检测３０例正常妇女对照（ＮＣ）和５０例正常妊娠妇女，ＮＣ组ＡＰＣ－Ｒ比率为２．８８±０．３７，ＮＰ组为２．０４±０．３１（ＡＰＣ－Ｒ阳性率为４２％）；ＮＣ组 ＬＡ阳性率为 ０， ＮＰ组为 ３６．７％； ＮＣ组 Ｆ１＋２为（０．７３４ ± ０．４２） ｎｍｏｌ／Ｌ， ＮＰ组为（ １．０５ ± ０．６９） ｎｍｏｌ／Ｌ； ＮＣ组Ｄ－Ｄ为（０．４８±０．０５）ｍｇ／Ｌ，ＮＰ组为（０．６３±０．１１）ｍｇ/Ｌ；ＮＰ组的ＡＰＣ比率、Ｆ１＋２和Ｄ－Ｄ的测定结果均较ＮＣ组有显著性差异。结论妊娠可能发生与ＬＡ升高有关的ＡＰＣ－Ｒ，并导致了凝血酶激活物生成增加以及凝血酶、纤溶酶的激活和继发性纤溶的发生。     

Effect of gamma irradiation with 30 Gy on the coagulation system in leukoreduced fresh-frozen plasma

BACKGROUND: The aim of this study was to investigate the effect of gamma irradiation with 30 Gy on the coagulation system in leukoreduced fresh-frozen plasma (FFP). STUDY DESIGN AND METHODS: In 74 FFP units that had been stored for 352 +/- 103 days below -30 degrees C, the following variables were determined in parallel in an irradiated and not irradiated half: prothrombin time (PT); activated partial thromboplastin time (APTT); thrombin time; antithrombin III; protein C; protein S; von Willebrand factor antigen; ristocetin cofactor; plasminogen-alpha(2)-antiplasmin; the coagulation factors fibrinogen, factor (F)II, FV, FVII, VIII, F IX, FX, FXI, FXII, FXIII, and activated factor XII (FXIIa); D-dimer; fibrin monomer; thrombin-antithrombin complex; prothrombin fragment 1 + 2 (F1+2); plasmin-alpha(2)-antiplasmin complexes (PAPs); and platelet factor 4. The FVII activity ratio was assayed to quantify activation of FVII. RESULTS: Irradiation with 30 Gy resulted in a reduction of APTT (35.0 +/- 4.1 sec vs. 34.4 +/- 4.1 sec; p = 0.00000006) and PT (89.8 +/- 8.2% vs. 90.7 +/- 8.0%; p = 0.002) and a significant increase of the activities of the coagulation factors FII, FV, FVII, F IX, FX, and FXII. FVIII activity decreased from 118 +/- 31 to 116 +/- 32 percent (p = 0.02). Activation of the coagulation system was shown by an increase in the FVII activity ratio (1.19 +/- 0.29 vs. 1.31 +/- 0.34; p = 0.0000001), FXIIa (0.81 +/- 0.50 ng/mL vs. 0.90 +/- 0.51 ng/mL; p = 0.006), and F1+2 (1.19 +/- 0.20 nmol/L vs. 1.24 +/- 0.20 nmol/L; p = 0.000005) after irradiation with 30 Gy, whereas an increase of PAP (16.2 +/- 11.5 ng/mL vs. 20.2 +/- 12.0 ng/mL; p = 0.0004) demonstrated activation of the fibrinolytic system. No negative influence of irradiation with 30 Gy on inhibitors of coagulation was observed. CONCLUSION: Gamma irradiation of leukoreduced FFPs with 30 Gy results in a significant but very weak activation of the coagulation and fibrinolytic system in FFPs.     

Characteristics of high-affinity and low-affinity adenosine binding sites in human cerebral cortex

The binding characteristics of human brain cortical membrane fractions were evaluated to test the hypothesis that there are A1 and A2 adenosine binding sites. The ligands used were 2-chloro[8-3H]adenosine and N6-[adenine-2,8-3H]cyclohexyladenosine. Binding of chloroadenosine to human brain cortical membranes was time dependent, reversible, and concentration dependent. The dissociation constant (Kd) calculated for chloroadenosine by Scatchard analysis of equilibrium data was 280 nmol/L, with a maximum binding (Bmax) of 1.6 pmol/mg protein, suggesting a single class of binding sites. The specificity of chloroadenosine binding was assessed by the ability of adenosine analogues to compete for binding sites. With this approach, the apparent Kd was estimated to be 0.74 mumol/L for 5'-N-ethylcarboxamideadenosine, 1 mumol/L for cyclohexyladenosine, and 13 mumol/L for N6-(L-2-phenylisopropyl)adenosine. Isobutylmethylxanthine and theophylline, receptor antagonists, had apparent Kd values of 84 mumol/L and 105 mumol/L, respectively. Hill slope factors ranged from 0.3 to 0.6. Chloroadenosine binding to human brain cortical membranes approached equilibrium at 90 minutes, with a t 1/2 of 10 minutes. The kob was 0.080/min, and the k1 was 7.5 X 10(4)/min/mol/L. Reversibility of chloroadenosine binding at equilibrium was completed at approximately 10 minutes, with a k2 value of 0.074/min. The Kd calculated from the rate constants was 990 nmol/L. Cyclohexyladenosine binding was concentration dependent. The Kd calculated for cyclohexyladenosine via Scatchard analysis of equilibrium data was 5 nmol/L with a Bmax of 0.35 pmol/mg protein. Cyclohexyladenosine binding was displaced by three known receptor agonists: N6-(L-2-phenylisopropyl)adenosine (Kd 4 nmol/L), 2-chloroadenosine (Kd 10 nmol/L) and 5'-N-ethylcarboxamideadenosine (Kd 6 nmol/L).(ABSTRACT TRUNCATED AT 250 WORDS)     

Systemic absorption of inhaled epinephrine

To determine the systemic absorption of epinephrine when it is given by inhalation, six normal volunteers were given 15 puffs, followed by 30 puffs, of epinephrine from a pressurized aerosol (160 micrograms epinephrine/puff). The peak mean (+/- SE) plasma epinephrine levels were 1.50 (+/- 0.61) and 4.22 (+/- 1.93) nmol/L 1 minute after each dose, respectively. The effect on physiologic finger tremor correlated with the plasma epinephrine level and returned to baseline 20 minutes after taking the higher dose. There was a small fall in mean plasma potassium levels of 0.45 mmol/L and a small rise in plasma glucose levels of 0.81 mmol/L. On a separate occasion an injection of 0.3 ml of 1/1000 (300 micrograms) epinephrine was given subcutaneously to the same individuals. This caused a peak plasma epinephrine level of 2.43 (+/- 0.47) nmol/L at 10 minutes, and this was still raised at 2.05 (+/- 0.41) nmol/L after 40 minutes. The maximum fall in the mean plasma potassium level was 0.43 mmol/L after the injection.     

Anticoagulation with low-molecular-weight heparin (dalteparin) in plasmapheresis therapy: initial experience

BACKGROUND: In contrast to other extracorporeal treatments no established regime exists for anticoagulation with low-molecular-weight heparin (LMWH) in plasmapheresis therapy. A study was conducted to investigate whether LMWH (dalteparin-Na) is suitable as an effective anticoagulant in plasmapheresis therapy. STUDY DESIGN AND METHODS: Eleven patients with autoimmune neurological diseases and the necessity for a plasmapheresis therapy were enrolled. A capillary membrane filter was used. A total of 2000 mL of human plasma was isovolumetrically exchanged per plasmapheresis cycle. The anticoagulation was accomplished with a single bolus of LMWH (dalteparin) of 80 to 90 IU per kg of body weight. The system was visually monitored. Anti-factor (F)Xa activity, thrombin-antithrombin III complex (TAT), and prothrombin fragment 1+2 (F 1+2) were determined at regular intervals. Samples were taken from the collected plasma pool to determine the loss of LMWH during the plasmapheresis procedure. RESULTS: All plasmapheresis cycles with LMWH were successful without complications. Approximately 40 percent of the initially administered LMWH bolus was lost by the large porous filter during the plasmapheresis. The anti-FXa values were determined to be 0.5 IU per mL during the entire plasmapheresis. TAT values were elevated (TAT median, 14.3 microg/L). F 1+2 values measured before the filter cartridge remained within the normal range for the entire plasmapheresis cycle (<1.2 nmol/L) and were increasingly elevated after the filter. CONCLUSION: Our initial experiences with LMWH for anticoagulation in plasmapheresis indicate that a body weight adjusted dose of LMWH (dalteparin) is suitable for anticoagulation in plasmapheresis therapy. No complications were observed. The data are encouraging. Further investigations will show if and how the present anticoagulation regime could be further optimized.     

125I radioimmunoassay for 17 alpha-hydroxyprogesterone in plasma, for diagnosing and managing congenital adrenal hyperplasia

This rapid, inexpensive, and sensitive radioimmunoassay (RIA) for plasma 17 alpha-hydroxyprogesterone involves radioiodination. A single extraction with toluene/hexane removes an average 93% of the hormone from 0.1 mL of plasma. The extract is evaporated and the hormone is estimated by a simple, precise, and accurate 125I RIA involving a specific rabbit antiserum. A suspension of dextran-coated charcoal is used to separate free and bound steroid. Inter- and intra-assay CVs were less than 15 and less than 10%, respectively, and the sensitivity was 3 pg per assay tube. The regression equation for data on 17 alpha-hydroxyprogesterone added to steroid-free plasmas was y = 0.94x + 2.2 (r = 0.99). However, the turnaround time is only one-half to one-tenth that for most 3H RIA (3 h vs 6 to 30 h). The ranges of values found for plasma from normal subjects, treated and untreated patients with congenital adrenal hyperplasia, and infants with newly detected congenital adrenal hyperplasia were, respectively, 1 to 11, 0 to 20, 30 to 620, and 270 to 4900 nmol/L.     

A sensitive high-temperature electrothermal atomic absorption analysis for Rb+ in erythrocytes and plasma of normal and hypertensive persons

This method for determination of Rb+ in human plasma and erythrocytes by graphite-furnace atomic absorption spectrophotometry has a sensitivity of 29 nmol/L for plasma, 12 nmol/L for erythrocytes. The detection limit is 24 nmol/L for plasma, 4.8 nmol/L for erythrocytes. This assay is approximately 30-fold more sensitive than previously reported techniques involving atomic absorption spectrophotometry, enabling use of smaller samples. The rubidium signal is linear with concentration up to 1.2 mumol/L, and addition of other cations to the matrix produces only minor alterations in the Rb+ signal. We measured plasma and erythrocytic Rb+ concentrations in healthy subjects and in patients with untreated essential hypertension. In both, our values are similar to those previously reported for healthy individuals.     

Aging-associated changes in indices of thrombin generation and protein C activation in humans. Normative Aging Study.

In view of the known association of vascular disease with increasing age, we have conducted an analysis of hemostatic system activity with respect to perturbations induced by aging phenomena. We have utilized an immunochemical assay for prothrombin fragment F1 + 2 to quantify Factor Xa activity upon prothrombin in the plasma of 199 healthy males between the ages of 42 and 80. The levels of F1 + 2 in this population generally increased as a function of age (P less than 0.0001). The metabolic behavior of this marker was determined in 10 individuals greater than 65 yr of age with varying levels of F1 + 2, which ranged from 1.28 to 5.85 nM. The elevations in the concentration of this component were not due to diminished clearance of the fragment. Radio-immunoassays for fibrinopeptide A (FPA) and the protein C activation peptide (PCP) were subsequently employed to measure thrombin activity upon fibrinogen and thrombin-thrombomodulin activity upon protein C, respectively, in 82 members of this population ranging in age from 42 to 80. Significant positive correlations were again observed between increasing age and the level of F1 + 2 (P less than 0.0001) as well as FPA (P less than 0.01) and PCP (P less than 0.002). The results of this cross-sectional study indicate that many apparently normal males of increasing age with normal immunologic levels of antithrombin III and protein C exhibit a biochemical defect that denotes the presence of an acquired prethrombotic state.     

Suppression of hemostatic system activation by oral anticoagulants in the blood of patients with thrombotic diatheses.

RIAs for hemostatic system activation were employed to study patients who were anticoagulated with warfarin. The mean prothrombin fragment F1 + 2 concentration in stably anticoagulated individuals without an inherited thrombotic diathesis (mean prothrombin time [PT] ratio [PT of patient/PT of normal plasma pool] = 1.74) was 0.231 nM as compared with a mean plasma F1 + 2 level of 1.68 nM for a nonanticoagulated control group (P less than 0.0001). The initiation of oral anticoagulants in two subjects who did not exhibit protein C deficiency led to a paradoxical increase in F1 + 2 levels during the first day of therapy. We have also shown that a relatively low intensity regimen of warfarin (PT ratio less than 1.2) may reduce elevated concentrations of F1 + 2 into the normal range in patients with a history of recurrent thromboembolism. The mean F1 + 2 level in antithrombin-deficient individuals on warfarin was significantly elevated (mean = 0.714 nM) as compared with that in anticoagulated subjects with protein C deficiency (mean = 0.205 nM) or in those without an inherited thrombotic disorder (P less than 0.01) at equivalent levels of intensity of oral anticoagulation. We therefore conclude that the effect of warfarin on hemostatic system activation is modulated by the endogenous heparan sulfate-antithrombin mechanism.     

心理应激对不同行为类型者血浆环核苷酸含量的影响

背景在分子生物学基础上探讨冠心病发病中介机制研究的较少,而从这一水平上研究冠心病的发病机制十分有利于其预防和控制.目的了解不同行为类型应激者血浆环核苷酸变化,为探讨心理行为因素引起冠心病的中介机制的研究提供前瞻性资料.设计前瞻性研究.地点、对象和方法通过问卷从300名志愿者中随机筛选出A型行为与B型行为高考生各19人为研究对象,考前80d和考前1d分别于1630～1700取潍坊一中A、B型行为学生静脉血,检测血浆环核苷酸含量,观察心理应激(应激源为高考)对不同行为类型者血浆环核苷酸含量的影响.主要观察指标应激前后血浆环核苷酸含量.结果应激前A型行为高考生的血浆环一磷酸腺苷(cAMP)含量[(15.46±3.56)nmol/L]显著高于B型行为的高考生[(12.09±2.78)nmol/L],差异有非常显著性意义(t=3.25,P＜0.01);应激后,A型行为高考生的cAMP,cAMP/环一磷酸鸟苷(cGMP)降低[分别为(10.911±3.950),(5.526±1.488)nmol/L],与应激前比较,差异有显著性意义(t=12.25,8.14,P＜0.001),cGMP升高了[(2.962±0.764)nmol/L](t=-906,P＜0.001);B型行为高考生的cAMP,cAMP/cGMP降低[分别为(7.379±1.762),(3.677±1.488)nmol/L](t=7.42,7.56,P＜0.001);cGMP升高了[(2.280±0.685)nmol/L](t=-7.52,P＜0.001);A型行为考生cAMP,cAMP/cGMP下降幅度显著大于B型行为高考生(t=3.56,3.83,P＜0.001).结论高考应激对A型行为高考生血浆环核苷酸含量影响显著大于B型行为高考生.     

Detection of protein C activation in humans

We have developed a radioimmunoassay (RIA) for the dodecapeptide that is liberated from protein C when this zymogen is activated by thrombin bound to thrombomodulin present on the vascular endothelium. The protein C activation peptide (PCP) was synthesized using the solid-phase method of Merrifield. Antisera were raised in rabbits to the synthetic analogue coupled to bovine serum albumin with glutaraldehyde. The antibody population obtained was used together with a 125I-labeled tyrosinated ligand and various concentrations of unlabeled PCP to construct a double antibody RIA capable of measuring as little as 10 pM of this component. We have established that the synthetic dodecapeptide has the same immunoreactivity as the native peptide and that the reactivity of protein C is less than 1/2,000 that of PCP on a molar basis. The extremely low levels of peptide in normal individuals as well as the nonspecific contributions of plasma constituents to the immunoreactive signal, necessitated the development of a procedure by which the PCP could be reproducibly extracted from plasma and concentrated approximately 20-fold. This methodology permitted us to demonstrate that the plasma PCP levels in 17 normal donors averaged 6.47 pM, and that elevations up to 180 pM were observed in individuals with evidence of disseminated intravascular coagulation. The validity of these measurements of protein C activation is supported by the fact that, in both of these situations, the RIA signal migrates on reverse-phase high pressure liquid chromatography in a manner identical to that of the native dodecapeptide. We have also noted that the mean PCP concentration in seven patients fully anticoagulated with warfarin averaged 2.61 pM. Our studies also show that PCP is cleared from the plasma of primates with a t1/2 of approximately 5 min. Given that the t1/2 of activated protein C is estimated to be 10-15 min, the latter enzyme appears to exert its effects on the activated cofactors of the coagulation system at concentrations considerably less than 1.0 nM.     

Evidence for activation of the coagulation system in migraine with aura

Migraine with aura has been shown to be an independent risk factor for stroke. Although the precise mechanism of migraine-related stroke is not known, risk factors for hypercoagulability have been found in migraineurs. Prothrombin factor 1.2 (F1.2) is a cleavage product of prothrombin. Elevated plasma F1.2 has been shown to be a sensitive and a specific marker of ongoing thrombin generation, and thus may serve as an indicator of hypercoagulability. In this study we determined plasma F1.2 levels in 35 patients with migraine (22 with aura and 13 without aura) and in 24 healthy age- and sex-matched volunteers. Elevated F1.2 levels were found in 11 of 22 (50%) patients with migraine with aura (1.25-3.5 nmol/l). None of the patients with migraine without aura nor any of the healthy volunteers had elevated plasma F1.2 levels (normal < 1.1 nmol/l). We conclude that prothrombin F1.2 levels are elevated in a significant number of patients with migraine with aura but not in patients with migraine without aura. This finding suggests that there is activation of the clotting system in certain patients with migraine with aura.     

An automated biotin—streptavidin procedure for progesterone evaluation

An automated biotin-streptavidin procedure for measuring progesterone in serum is described. The method is linear up to 98.3 nmol/L and the calibration curve is stable for at least 14 days. The lower limit of progesterone detection is 0.70 nmol/L. Although serum is the preferred specimen, progesterone levels can be measured in EDTA, heparin, or citrated plasma. There is no interference from samples with monoclonal proteins or from hemoglobin and bilirubin at concentrations of 9.62 g/L and 899 mumol/L, respectively. Lipemic samples will lower the progesterone levels. Total imprecision of the method in the range of 19-80.4 nmol/L gave CVs between 4.6 and 7.3%. Progesterone values obtained with this biotin-streptavidin procedure agreed with those obtained by the DPC RIA assay (r = 0.991). The biotin-streptavidin procedure can be used as an alternative to RIA for measurement of progesterone.     

Effect of diazepam on adenosine 3',5'-cyclic monophosphate (cAMP) plasma levels in anesthetized patients

BACKGROUND: It has been previously demonstrated that diazepam inhibits the cyclic nucleotide phosphodiesterase type 4 isozyme (PDE4). PDE enzymes mediate the hydrolysis of the nucleotide adenosine 3',5'-cyclic monophosphate (cAMP). OBJECTIVE: The aim of this study was to determine whether IV administration of diazepam affects cAMP plasma levels in anesthetized patients. METHODS: In this prospective study, patients scheduled to undergo elective myocardial revascularization surgery with anesthetization with etomidate (0.3 mg/kg), fentanyl (total dose 20-25 microg/kg), and cisatracurium (150 microg/kg), supplemented with sevoflurane (2% in an oxygen/air mixture), were randomly assigned to 1 of 3 groups to receive diazepam (0.28 mg/kg IV), diazepam vehicle (alcohol and propylene glycol IV), or saline. Before the start of the surgical procedure, at 5 and 10 minutes after administration of diazepam, vehicle, or saline, blood samples were obtained for determination of the diazepam, cAMP, and catecholamine levels. RESULTS: Ten patients received diazepam, 10 received vehicle, and 5 received saline. The mean (SEM) arterial serum concentrations of diazepam were 2.1 (0.2) microg/mL and 1.1 (0.4) microg/mL, respectively, at 5 and 10 minutes after administration. cAMP plasma levels increased from mean (SEM) baseline values of 30.0 (1.7) nmol/L to 35.5 (1.5) nmol/L (P < 0.05) and 43.1 (1.7) nmol/L (P < 0.05) at 5 and 10 minutes, respectively, after diazepam administration. No significant changes in cAMP plasma levels were observed compared with the mean (SEM) baseline value of 32.0 (1.7) nmol/L at 5 minutes (31.8 [1.3] nmol/L) and 10 minutes (30.9 [1.4] nmol/L) after vehicle administration. Epinephrine plasma concentration increased from a mean (SEM) baseline value of 0.13 (0.02) ng/mL to 0.22 (0.02) ng/mL (P < 0.05) at 10 minutes after administration of vehicle and 0.21 (0.02) ng/mL (P < 0.05) at 10 minutes after administration of diazepam. CONCLUSION: In this preliminary study, diazepam increased cAMP plasma levels in anesthetized patients, presumably through inhibition of PDE4 activity.     

Possible role of vascular intima for generation of coagulant activity in patients undergoing coronary thrombolysis with recombinant tissue-type plasminogen activator. A randomized, placebo-controlled study.

In our present placebo-controlled study on recombinant tissue-type plasminogen activator (rt-PA) and heparin treatment of patients with acute ischaemic heart disease (IHD), we studied the extent of fibrin resolution and generation of coagulant activity. In rt-PA treated patients the lysis of fibrin in vivo (median 60 nmol of fibrin--estimated as fibrinogen equivalents) was significantly higher (p less than 0.02) than can be accounted for solely by lysis of a coronary thrombus (approximately 2 nmol) and circulating soluble fibrin (median 15 nmol). We observed a 200% increase of plasma concentrations of both prothrombin fragment 1 + 2 (p less than 0.001) and thrombin-antithrombin III complexes (p less than 0.001) as a consequence of rt-PA treatment, indicating that the coagulant activity is primarily caused by a physiological activation of the coagulation system. We conclude that an important contribution to the activation of coagulation in patients undergoing coronary thrombolysis is lysis of fibrin deposited widespread on the vascular intima, and that this process causes an intimal-dependent activation of the coagulation system.     

The effect of oral contraceptives on plasma-free and salivary cortisol and cortisone

The effect of a low estrogen oral contraceptive (OC) on glucocorticoid levels in plasma and saliva as well as glucocorticoid binding was studied in 23 healthy women using 30 micrograms ethinyl estradiol (EE2) + 150 micrograms desogestrel (Marvelon) (II). Fifteen healthy females with normal menses served as controls (I). Blood and salivary samples were taken between 9.00 and 9.30 a.m. on the 18th day of menstrual or pill cycle. Assay accuracy had been optimised by applying extraction and chromatographic purification before radioimmunoassay (RIA) of cortisol and cortisone in both plasma and salivary samples. Free steroid assays were performed by applying the same procedure to equilibrium dialysates obtained after dialysing plasma against an equal volume of buffer, instead of measuring tracer distribution. Corticosteroid Binding Globulin (CBG) was measured by a commercial RIA. As expected, CBG as well as plasma total cortisol were elevated in the pill group. Interestingly both plasma free and salivary cortisol were higher than in controls (free cortisol I: 18.0 +/- 7.95 nmol/l; II: 32.3 +/- 9.03 nmol/l; salivary cortisol I: 9.2 +/- 3.88 nmol/l; II: 18.8 +/- 6.92 nmol/l. Salivary cortisol closely parallelled plasma free cortisol both within and between the groups, though at a much lower level (about 50%). Free cortisone was slightly lower in the pill group (I: 10.8 +/- 2.55 nmol/l; II 8.5 +/- 1.86 nmol/l) whereas salivary cortisone was 2.3 (I) and 4.4 (II) times higher than plasma free cortisone and tended to follow the plasma free and salivary cortisol pattern, both within and between the study groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dementia in subjects with atrial fibrillation: hemostatic function and the role of anticoagulation

BACKGROUND: Atrial fibrillation (AF) is associated with cognitive impairment and dementia, perhaps through encouraging a prothrombotic state and cardioembolism. OBJECTIVES: We wished to test the hypotheses that hemostatic function is altered in subjects with AF who develop dementia, and that long-term warfarin anticoagulation is protective against this complication. PATIENTS AND METHODS: Recruitment was from an observational cohort study of AF. Baseline assessment included measurement of plasma fibrinogen, fibrin D-dimer, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin complexes (TAT), von Willebrand factor and tissue plasminogen activator. We assessed cognitive function after 3 years' follow-up using the 13-item modified Telephone Interview for Cognitive Status (TICSm) and the short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). RESULTS: Of the 218 subjects assessed, 145 (66%) were prescribed warfarin. Forty-nine (22%) met TICSm/IQCODE criteria for dementia. D-dimer, F1+2 and TAT levels were higher in AF subjects with dementia compared with those without (medians 81 vs. 60 ng mL(-1), P = 0.008; 0.76 vs. 0.49 nmol L(-1), P = 0.006; and 1.78 vs. 1.44 microg L(-1), P = 0.003, respectively). These associations became of borderline statistical significance following adjustment for age. Logistic regression showed a trend towards warfarin use being independently associated with reduced prevalence of dementia (odds ratio 0.52, P = 0.08). CONCLUSIONS: We found evidence of increased thrombin generation and fibrin turnover in subjects with AF and dementia compared with those without dementia. Long-term warfarin use may be protective against the development of dementia in subjects with AF.     

Multiple plasma exchanges successfully maintain a young adult patient with Crigler-Najjar syndrome type I

Plasmapheresis has been shown to reduce total and free bilirubin levels in acute exacerbations of Crigler-Najjar syndrome, type I (CNS-TI), but its effectiveness in long-term management has not been reported. An 18-year-old (yo) male with CNS-TI, who required prolonged daily high-intensity phototherapy to prevent cerebral nervous system symptoms, developed increasingly frequent bouts of confusion, nausea, and vomiting associated with free bilirubin concentrations (fbcs) greater than 10-15 nmol/L. Pending consideration of orthotopic liver transplantation, plasma exchange (approximately 3 liters per procedure) was begun in 12/84 using the IBM/COBE 2997 with 5% albumin as replacement fluid. Frequency of treatments was guided by twice weekly fbcs, with plasma exchange for fbc greater than 10-15 nmol/L. Pre-exchange and postexchange fbcs ranged from 27.5 to 11 nmol/L and 9.2 to 2 nmol/L, respectively. Seventy-two exchanges were performed over a 28 month period. Irreversible CNS damage did not occur, and the patient underwent successful liver transplantation in April of 1987, with complete correction of his metabolic disorder. He remains well 18 months following transplantation.