An experimental examination of the effects of alcohol consumption and exposure to misleading postevent information on remembering a hypothetical rape scenario

We experimentally examined the effects of alcohol consumption and exposure to misleading postevent information on memory for a hypothetical interactive rape scenario. We used a 2 beverage (alcohol vs. tonic water) × 2 expectancy (told alcohol vs. told tonic) factorial design. Participants (N = 80) were randomly assigned to conditions. They consumed alcohol (mean blood alcohol content = 0.06%) or tonic water before engaging in the scenario. Alcohol expectancy was controlled by telling participants they were consuming alcohol or tonic water alone, irrespective of the actual beverage they were consuming. Approximately a week later, participants were exposed to a misleading postevent narrative and then recalled the scenario and took a recognition test. Participants who were told that they had consumed alcohol rather than tonic reported fewer correct details, but they were no more likely to report incorrect or misleading information. The confidence-accuracy relationship for control and misled items was similar across groups, and there was some evidence that metacognitive discrimination was better for participants who were told that they had consumed alcohol compared with those told they had tonic water. Implications for interviewing rape victims are discussed.

Age-related differences in spontaneous trait judgments from facial appearance

We tested whether there are age-related declines in detecting cues to trustworthiness, a skill that has been demonstrated to be rapid and automatic in younger adults. Young (M _age = 21.2 years) and older (M _age = 70.15 years) adults made criminal appearance judgments to unfamiliar faces, which were presented at a duration of 100, 500 or 1,000 ms. Participants' response times and judgment confidence were recorded. Older were poorer than young adults at judging trustworthiness at 100 ms, and were slower overall in making their judgments. Further, the cues (i.e. perceptions of anger, trustworthiness and happiness) underlying criminality judgments were the same across age groups. Judgment confidence increased with increasing exposure duration for both age groups, while older adults were less confident in their judgments overall than their young counterparts. The implications are discussed.

The own-race bias in child and adolescent witnesses

This study investigated the own-race bias in British school children using an eyewitness paradigm. Some 319 participants viewed films of two similar staged thefts, one that depicted a Caucasian culprit and the other an Asian culprit, and then after a delay of 2–3 days, viewed a line-up for each culprit. One hundred and seventy-six of the participants were Caucasian and 143 were Asian. There were also two age groups: 164 were aged 7–9 years and 152 were 12–14 years. There was a significant own-race bias for Caucasian participants from both age groups that resulted in more correct identifications for the own-race culprit from target present line-ups and more false identifications for the target absent line-ups. Asian participants from both age groups showed no own-race bias and performed equally accurately for culprits of both races. Measures of inter-racial contact were associated with correct responses for other-race targets and revealed that the majority of Caucasian participants in the current sample had very little contact with Asians, whereas the majority of Asian participants had high levels of contact with Caucasians.

The Effects of Alcohol Intoxication on Accuracy and the Confidence-Accuracy Relationship in Photographic Simultaneous Line-ups

Acute alcohol intoxication during encoding can impair subsequent identification accuracy, but results across studies have been inconsistent, with studies often finding no effect. Little is also known about how alcohol intoxication affects the identification confidence-accuracy relationship. We randomly assigned women (N = 153) to consume alcohol (dosed to achieve a 0.08% blood alcohol content) or tonic water, controlling for alcohol expectancy. Women then participated in an interactive hypothetical sexual assault scenario and, 24 hours or 7 days later, attempted to identify the assailant from a perpetrator present or a perpetrator absent simultaneous line-up and reported their decision confidence. Overall, levels of identification accuracy were similar across the alcohol and tonic water groups. However, women who had consumed tonic water as opposed to alcohol identified the assailant with higher confidence on average. Further, calibration analyses suggested that confidence is predictive of accuracy regardless of alcohol consumption. The theoretical and applied implications of our results are discussed.

Receiver operating characteristic analysis of age-related changes in lineup performance

In the basic face memory literature, support has been found for the late maturation hypothesis, which holds that face recognition ability is not fully developed until at least adolescence. Support for the late maturation hypothesis in the criminal lineup identification literature, however, has been equivocal because of the analytic approach that has been used to examine age-related changes in identification performance. Recently, receiver operator characteristic (ROC) analysis was applied for the first time in the adult eyewitness memory literature to examine whether memory sensitivity differs across different types of lineup tests. ROC analysis allows for the separation of memory sensitivity from response bias in the analysis of recognition data. Here, we have made the first ROC-based comparison of adults' and children's (5- and 6-year-olds and 9- and 10-year-olds) memory performance on lineups by reanalyzing data from Humphries, Holliday, and Flowe (2012). In line with the late maturation hypothesis, memory sensitivity was significantly greater for adults compared with young children. Memory sensitivity for older children was similar to that for adults. The results indicate that the late maturation hypothesis can be generalized to account for age-related performance differences on an eyewitness memory task. The implications for developmental eyewitness memory research are discussed.

The impact of beliefs about face recognition ability on memory retrieval processes in young and older adults

This study examined whether beliefs about face recognition ability differentially influence memory retrieval in older compared to young adults. Participants evaluated their ability to recognise faces and were also given information about their ability to perceive and recognise faces. The information was ostensibly based on an objective measure of their ability, but in actuality, participants had been randomly assigned the information they received (high ability, low ability or no information control). Following this information, face recognition accuracy for a set of previously studied faces was measured using a remember-know memory paradigm. Older adults rated their ability to recognise faces as poorer compared to young adults. Additionally, negative information about face recognition ability improved only older adults' ability to recognise a previously seen face. Older adults were also found to engage in more familiarity than item-specific processing than young adults, but information about their face recognition ability did not affect face processing style. The role that older adults' memory beliefs have in the meta-cognitive strategies they employ is discussed.

Intoxicated witnesses and suspects: an archival analysis of their involvement in criminal case processing

Research about intoxicated witnesses and criminal suspects is surprisingly limited, considering the police believe that they are quite ubiquitous. In the present study, we assessed the involvement of intoxicated witnesses and suspects in the investigation of rape, robbery, and assault crimes by analyzing cases that were referred by the police to a prosecutor's office. Results indicated that intoxicated witnesses and suspects played an appreciable role in criminal investigations: Intoxicated witnesses were just as likely as sober ones to provide a description of the culprit and to take an identification test, suggesting criminal investigators treat intoxicated and sober witnesses similarly. Moreover, intoxicated suspects typically admitted to the police that they had consumed alcohol and/or drugs, and they were usually arrested on the same day as the crime. This archival analysis highlights the many ways in which alcohol impacts testimony during criminal investigations and underscores the need for additional research to investigate best practices for obtaining testimony from intoxicated witnesses and suspects.

Controlled release recombinant human interferon-α2b for treating patients with chronic hepatitis C genotype 1: a phase 2a clinical trial

Better convenience and tolerability and sustained therapeutic concentrations might improve interferon (IFN) treatment for chronic hepatitis C virus (HCV) infection. In an open-label, randomized study, controlled release free (chemically unmodified) recombinant human IFN-α(2b) in poly(ether-ester) microspheres (CR-rhIFN-α(2b)), was injected at doses of 160, 320, 480 or 640 μg every 2 weeks for 12 weeks with concomitant weight-based oral ribavirin in 32 treatment-naïve patients with chronic HCV genotype 1. Treatment was well tolerated, with 31 patients (97%) successfully completing the study. Full doses of CR-rhIFN-α(2b) were administered on 96% of scheduled occasions. Flu-like symptoms were generally mild and brief. Injection site reactions developed in 13 patients (41%), and neutropenia occurred in six of eight patients receiving 640 μg. In the 320, 480 and 640 μg groups, 62-75% of patients achieved a ≥2 log(10) HCV RNA reduction by 4 weeks and 88-100% by 12 weeks. For those groups, the pooled median time to ≥2 log(10) reduction was 11 days (95% confidence interval, 7-35 days). In those groups, viral reduction below the limit of detection was accomplished in 25% of patients by 4 weeks and in 62% by 12 weeks. The 160-μg dose was less potent. After CR-rhIFN-α(2b) injection, stable plateau levels of serum IFN-α(2b) were generally reached within 72 h. Treatment-emergent neutralizing antibodies to IFN-α(2b) were observed in one patient. No antibodies to host plant proteins were detected. CR-rhIFN-α(2b) with ribavirin cotherapy was well tolerated and displayed potent early antiviral activity in patients with chronic HCV genotype 1.

Reducing misinformation effects in older adults with cognitive interview mnemonics

We examined the effect of a prior Modified Cognitive Interview on young and older adults' recall of a short film of a staged crime and subsequent reporting of misinformation. Participants viewed the film followed the next day by misinformation presented in a postevent summary. They were then interviewed with either a Modified Cognitive Interview or a control interview followed by a recognition memory test. A Modified Cognitive Interview elicited more correct details and improved overall accuracy compared to a control interview in both age groups, although the young adults recollected three times more correct information in a Modified Cognitive Interview than the older adults. In both age groups, correct recollections of person and action details were higher in a Modified Cognitive Interview than a control interview. Importantly, older adults who were interviewed with a Modified Cognitive Interview were not susceptible to misinformation effects.

Signal transduction in larval trematodes: putative systems associated with regulating larval motility and behaviour

The multi-host lifestyle of parasitic trematodes necessitates their ability to communicate with their external environment in order to invade and navigate within their hosts' internal environment. Through recent EST and genome sequencing efforts, it has become clear that members of the Trematoda possess many of the elaborate signal transduction systems that have been delineated in other invertebrate model systems like Drosophila melanogaster and Caenorhabditis elegans. Gene homologues representing several well-described signal receptor families including receptor tyrosine kinases, receptor serine tyrosine kinases, G protein-coupled receptors and elements of their downstream signalling systems have been identified in larval trematodes. A majority of this work has focused on the blood flukes, Schistosoma spp. and therefore represents a narrow sampling of the diverse digenean helminth taxon. Despite this fact and given the substantial evidence supporting the existence of such signalling systems, the question then becomes, how are these systems employed by larval trematodes to aid them in interpreting signals received from their immediate environment to initiate appropriate responses in cells and tissues comprising the developing parasite stages? High-throughput, genome-wide analysis tools now allow us to begin to functionally characterize genes differentially expressed throughout the development of trematode larvae. Investigation of the systems used by these parasites to receive and transduce external signals may facilitate the creation of technologies for achieving control of intramolluscan schistosome infections and also continue to yield valuable insights into the basic mechanisms regulating motility and behaviour in this important group of helminths.

Receptor-ligand interactions and cellular signalling at the host-parasite interface

Although the effects of trematode infection on snail host physiology or host responses on parasite development have been well described in the literature, very little is known regarding the underlying mechanisms and specific molecules responsible for mediating those effects. It is presumed that many host-parasite interactions are communicated through receptor-mediated events, in particular those involving haemocytic immune responses to invading parasites, larval motility and migration through host tissues, and larval acquisition of host molecules either as nutrients or critical developmental factors. The intent of this chapter is to review current knowledge of molecules (both receptors and their ligands or counter-receptors) involved in molecular communication at the interface between larval trematodes, especially the mother or primary sporocyst stage, and host cells/tissues in intimate proximity to developing larvae. Information to date suggests that the molecular exchange at this interface is a highly complex and dynamic process, and appears to be regulated in specific cases. Topics discussed will focus on snail cell receptor interactions with the sporocyst tegument and its secretions, host cell-cell and cell-substrate adhesion receptors and their related signal transduction pathways, and sporocyst tegumental surface receptors and ligands involved in the binding of soluble host molecules.

Protein kinase C regulation of cell spreading in the molluscan Biomphalaria glabrata embryonic (Bge) cell line

Cellular adhesion and spreading are critical components involved in the processes of cell and tissue development, and immune responses in molluscs, but at present, little is known regarding the signaling pathways involved in these basic cellular functions. In the present study, the molluscan Biomphalaria glabrata embryonic (Bge) cell line was used as an in vitro model to study the signal transduction pathways regulating molluscan cell adhesion and spreading behavior. Western blot analysis using antibodies specific to mitogen-activated protein kinase (MAPK) revealed the presence of an MAPK-like immunoreactive protein in Bge cells, that was phosphorylated upon exposure to phorbol myristate acetate (PMA). Moreover, Bge cell treatment with inhibitors of protein kinase C (PKC), Ras and MAPK kinase (Mek) suppressed PMA-induced expression of activated MAPK, suggesting that PKC-, Ras- and Mek-like molecules may be acting upstream of MAPK. Similarly, in vitro Bge cell-spreading assays were performed in conjunction with the same panel of inhibitors to determine the potential involvement of PKC, Ras and Mek in cellular adhesion/spreading. Results revealed a similar pattern of inhibition of cell-spreading behavior strongly implying that the Bge cell spreading also may be regulated through a MAPK-associated signal transduction pathway(s) involving proteins similar to PKC, Ras and Mek.

Local adenovirus-mediated delivery of hirudin in a rabbit arterial injury model

Intravascular delivery of an E1/E3 deleted adenovirus encoding the hirudin protein reduces neointimal formation in the rat arterial injury model. Given the interspecies variability in response to adenoviral vectors, we tested this same construct in the hirudin-sensitive cholesterol-fed rabbit arterial balloon injury model. We hypothesized that local delivery of an E1/E3-deleted adenovirus encoding hirudin (Ad-Hir) in addition to early hirudin infusion would limit neointimal formation compared to early hirudin alone.

METHODS AND RESULTS

Local delivery of Ad-Hir, 2.5 x 10(10) PFU/ml, using a double balloon catheter [n = 6 vessels (v)] produced a 79% reduction in vessel wall thrombin activity at 48 h after balloon angioplasty (BA) compared with vehicle (Veh, n = 6v; p = 0. 05). In chronic experiments, hypercholesterolemic rabbits underwent femoral BA, and received either early hirudin alone (n = 9v) or early hirudin plus locally delivered Ad-Hir (early hirudin + Ad-Hir; n = 9v), an E1/E3-deleted adenovirus encoding beta-galactosidase (early hirudin + AdGal; n = 7v), or Veh (early hirudin + Veh; n = 10v). Early hirudin + Ad-Hir did not limit the arterial response to injury versus the other groups at 4 weeks after BA. Plaque area, cross-sectional luminal area narrowing by plaque, and T cell infiltration were significantly increased in the adenovirus- versus non-adenovirus-treated arteries. Plaque area correlated with T cell density.

CONCLUSION

Following BA in cholesterol-fed rabbits, local transduction with A-Hir produced a marked reduction in vessel wall-associated thrombin activity. However, this strategy increased rather than decreased the arterial response to BA injury. Our results suggest that the lack of therapeutic effect resulted from adenovirus-stimulated plaque formation, possibly resulting from a T cell-mediated inflammatory response.

Early plus delayed hirudin reduces restenosis in the atherosclerotic rabbit more than early administration alone: potential implications for dosing of antithrombin agents

BACKGROUND

A 2-hour infusion of r-hirudin at the time of balloon angioplasty limits restenosis in atherosclerotic rabbits. Because thrombin activity in the vessel wall after angioplasty remains high for 48 to 72 hours, we hypothesized that a second infusion of hirudin at 24 hours would reduce restenosis more than early treatment alone.

METHODS AND RESULTS

Femoral atherosclerosis was induced in 35 rabbits by air desiccation injury and a high-cholesterol diet. At the time of angioplasty, rabbits were randomly assigned to 1 of 4 groups: controls: heparin bolus, saline infusion at 24 hours; early hirudin: hirudin bolus+2 hours' infusion, saline infusion at 24 hours; delayed hirudin: heparin bolus, hirudin infusion+/-bolus at 24 hours; and early+delayed hirudin: hirudin bolus+2 hours' infusion, hirudin infusion+/-bolus at 24 hours. Rabbits were euthanized after 28 days. The early+delayed hirudin treatment group had less loss of minimal lumen diameter by angiography at 28 days. By histomorphometry, cross-sectional area narrowing by plaque was least in the early+delayed treatment group compared with controls (P=0.0001), early hirudin (P=0.01), or delayed hirudin (P=0.001). The early+delayed hirudin group also had a significant reduction in absolute plaque area and an improvement in lumen area compared with the other groups. No differences were observed between treatment groups with respect to the cross-sectional area encompassed by the internal or external elastic laminae.

CONCLUSIONS

Combined early+delayed administration of hirudin significantly reduces angiographic restenosis and cross-sectional area narrowing by plaque compared with early or late treatment alone. These results suggest that restenosis after balloon angioplasty is markedly influenced by thrombin-mediated events not only occurring early but also extending beyond the first 24 hours in this model.

Transcatheter regional urokinase therapy in the management of inferior vena cava thrombosis

PURPOSE

To study the efficacy of local infusion of urokinase (UK) in the treatment of symptomatic inferior vena cava (IVC) thrombosis.

MATERIALS AND METHODS

Eight patients (five men and three women) who ranged in age from 19 years to 75 years (mean, 56 years) with symptomatic IVC thrombosis underwent local catheter-directed infusion of UK with use of up to three access sites. Infrarenal IVC thrombus and iliac vein thrombus was identified in all patients. Four patients had extension of thrombus proximal to the renal veins. Seven of eight patients had at least one risk factor for IVC thrombosis: hypercoagulable state (n = 3), IVC filter (n = 3), malignancy (n = 2), recent surgery (n = 2), and oral contraceptive use (n = 1). No serious procedure-related complications were encountered, although one patient died 5 days after UK therapy of pulmonary failure due to advanced lung cancer. UK was infused for an average of 79 hours (range, 24-140 hours) and a mean total dose of 7.4 million U of UK (range, 2.9-14.4 million U). Adjunctive balloon angioplasty was performed in three patients. No vascular stents were placed. Clinical and/or radiographic follow-up was obtained in all eight patients.

RESULTS

Thrombolysis was successful in seven of eight (88%) IVCs with no or minimal residual thrombus. The remaining seven patients had no lower extremity swelling 2-24 months (mean, 11 months) after the procedure. Three of seven patients had computed tomographic or venographic follow-up (mean, 9 months; range, 1.5-15 months), demonstrating unchanged or improved IVC patency.

CONCLUSIONS

Transcatheter regional infusion of UK for re-establishing venous patency in acute IVC thrombosis appears to be effective with good short-term and mid-term clinical benefit.

Establishing an institution-specific therapeutic range for heparin

The relationship between heparin concentration and activated partial thromboplastin time (aPTT) in pooled plasma was compared with that in patient samples to assess the feasibility of using heparin-spiked pooled plasma in determining a therapeutic range for aPTT. Blood samples were taken from 32 patients who had been receiving intravenous unfractionated heparin sodium for more than 24 hours. The samples were stored at -70 degrees C until anti-Xa assay within three months of collection. Pooled normal plasma was spiked with unfractionated heparin sodium to produce nominal anti-Xa concentrations of 0, 0.05, 0.1, 0.2, and 0.5 unit/mL. Heparin concentrations and a aPTT values were measured, and the relationship between the two was determined by linear regression. For the ex vivo samples, the range of aPTT values corresponding to therapeutic heparin concentrations of 0.3-0.7 anti-Xa unit/mL was 64-106 seconds, which corresponds to an aPTT range of 2.3-3.9 times the mean of the normal range (compared with the traditionally defined therapeutic range of 1.5-2.5 times the control value). For the in vitro samples, the aPTT range corresponding to heparin concentrations of 0.3-0.7 unit/mL was 121-256 seconds, which corresponds to an aPTT range of 4.4-9.4 times the mean of the normal range. Each institution should establish a therapeutic aPTT range by calibrating aPTT values against heparin concentrations from blood samples of patients receiving intravenous heparin.

The inhibitor antibody response is more complex in hemophilia A patients than in most nonhemophiliacs with factor VIII autoantibodies. Recombinate and Kogenate Study Groups

Approximately 25% of hemophilia A patients infused with factor VIII (fVIII) mount an immune response, which leads to its inactivation. Anti-fVIII autoantibodies are also seen rarely in individuals with normal fVIII. We have previously demonstrated that some anti-A2 and anti-C2 domain antibodies are fVIII inhibitors and that many patients have additional inhibitors with a fVIII light chain (LCh) epitope outside C2. Because the contribution of the different antibodies to the plasma inhibitor titer had been examined in a limited number of patients (14), we report in this study a more extensive analysis of 55 plasmas. The dominant inhibitors in 62% (13 of 21) of autoantibody plasmas were directed only against C2 or A2, but not both, whereas this pattern was found in only 15% (5 of 34) of hemophilic plasmas. In addition, anti-A2 inhibitors were present in 71% (24 of 34) of hemophilic plasmas, but only 33% (7 of 21) of autoantibody plasmas. These results demonstrated that the inhibitor response in hemophiliacs was more complex and the epitope specificity was somewhat different. A comparison of hemophiliacs treated only with plasma fVIII or recombinant fVIII showed no significant differences in the complexity of the inhibitor response, as > or = 2 different inhibitor antibodies were present in 78% (18 of 23) of the former and 82% (9 of 11) of the latter. In contrast, the major inhibitors in 35% (8 of 23) of hemophiliacs treated with plasma fVIII were directed against C2 and another LCh epitope within residues 1649-2137, but not A2, while none (0 of 11) treated with recombinant fVIII had this pattern.

Cholinergic, serotoninergic and peptidergic components of the nervous system of Haematoloechus medioplexus (Trematoda, Digenea), characterised by cytochemistry

Cholinergic, serotoninergic and peptidergic neuronal pathways have been demonstrated in whole-mount preparations of the frog-lung digenean trematode, Haematoloechus medioplexus, using enzyme cytochemical methodologies and indirect immunocytochemical techniques in conjunction with confocal scanning laser microscopy. All 3 classes of neuroactive substance were found throughout both central and peripheral elements of a well-developed orthogonal nervous system. Peptidergic immunoreactivity was particularly strong, using antisera directed to native flatworm neuropeptides, neuropeptide F, and FMRF amide-related peptides (FaRPs), and there was significant overlap in the staining with that for cholinergic components. The serotoninergic system appeared quite separate, with the staining localised to a different set of neurons.

Infectivity and growth of Echinostoma revolutum (Froelich, 1802) in the domestic chick

Infectivity and growth studies in domestic chicks were carried out on a strain of Echinostoma revolutum isolated from Lymnaea elodes snails in Indiana, U.S.A. Of 21 chicks, each fed 40 +/- 10 cysts of Echinostoma revolutum, 16 (64%) were infected with a total of 269 (32%) worms from approximately 840 cysts. Worms were found only in the ceca and rectum at 2-14 days p.i. In vivo excysted metacercariae were obtained in the lower ileum and ceca at 4 h p.i. Excysted metacercariae averaged 0.2 mm in length and 0.02 mm2 in body area. Worm length averaged 1.3 mm on day 6, 2.3 mm on day 8 and 3.6 mm on day 14. Mean body area averaged 0.29 mm2 on day 6, 0.62 mm2 on day 8 and 1.93 mm2 on day 14. Worms first became ovigerous on day 12. Growth of E. revolutum in the chick was delayed compared to previous findings on E. trivolvis, a closely related species of 37-collar-spined echinostome in the E. revolutum complex.

Vaccination with fixed feline immunodeficiency virus (FIV) infected cells: protection, breakthrough and specificity of response

Infection of cats with feline immunodeficiency virus (FIV), a naturally occurring lentivirus infection of cats which causes an AIDS-like disease, has generated considerable interest as an animal model for HIV vaccination. This paper reports on experiments performed to examine the potential of a fixed infected cell vaccine to confer protection against intraperitoneal challenge with cell-free FIV. The cell vaccine was highly immunogenic and elicited antibody responses to virus core antigen, p24, high virus neutralizing (VN) antibody titres, and antibodies which recognized cellular components of the vaccine. Whilst protection, assessed by the inability to detect infectious virus by virus isolation or polymerase chain reaction, against homologous but not heterologous FIV isolates was apparent up to week 12 post-challenge, when cats were monitored longer up to week 50 post-challenge a breakthrough in vaccine protection against homologous virus was observed. Protection could not be correlated with levels of antibody to p24 or VN antibody titres. In contrast with simian immunodeficiency virus vaccine studies in macaques there was no clear evidence that antibodies recognizing cellular components of the vaccine, including MHC class I and II antigens, conferred any protective effect following challenge. These results indicate that long-term post-challenge monitoring for infection is essential in lentivirus vaccine trials.

Arterial thrombin activity after angioplasty in an atherosclerotic rabbit model: time course and effect of hirudin

BACKGROUND

A 2-hour infusion of the direct thrombin inhibitor hirudin at the time of balloon angioplasty limits restenosis in the focally atherosclerotic rabbit. Although short-term administration of hirudin may have a prolonged biological effect, the effect of hirudin on vessel thrombin activity has not been previously studied in an animal model of angioplasty. We hypothesized that a short intravenous infusion of hirudin would result in prolonged inhibition of arterial wall-associated thrombin activity (ATA) after angioplasty.

METHODS AND RESULTS

Sixty-one rabbits received recombinant hirudin (r-hirudin)(1 mg/kg bolus plus 1 mg x kg(-1) x h(-1)x2hours) or bolus heparin (controls, 150 U/kg) intravenously at the time of femoral balloon angioplasty. ATA was measured through exposure of arterial segments ex vivo to fibrinogen and conducting an assay for fibrinopeptide A (FPA). ATA was low in nonballooned, atherosclerotic vessels (FPA=0.5+/-0.3 ng x mL(-1) x mg(-1)) but increased significantly at 24 hours after angioplasty in the heparin group (3.7+/-0.9 ng x mL(-1) x mg(-1), P<.01 versus baseline, n=9) but not in the hirudin group (FPA = 1.4+/-0.3; P=NS versus baseline, P<.02 versus heparin controls, n=8). The time course of ATA after angioplasty was assessed in 44 rabbits. Thrombin activity peaked at 48 hours and declined to baseline at 72 hours and 7 days. FPA values between the heparin and r-hirudin groups were similar at these later time points.

CONCLUSIONS

A 2-hour intravenous infusion of r-hirudin suppressed ATA measured 24 hours after angioplasty in the focally atherosclerotic rabbit. This prolonged biological effect may account, in part, for the reduction in restenosis seen in this model.

D-dimer testing and acute venous thromboembolism. A shortcut to accurate diagnosis?

D-dimer fragments can be measured easily in plasma and whole blood, and the presence or absence of D-dimer could be useful in the diagnostic evaluation of venous thromboembolism. We systematically reviewed the English literature for articles that compared D-dimer results with those of other tests for deep venous thrombosis or pulmonary embolism. Twenty-nine studies were selected for detailed review, and we noted wide variability in assay performance, heterogeneity among subjects, and failure to define absence or presence of venous thromboembolism by a comprehensive criterion standard for diagnosis. These methodologic problems limit the generalizability of the published estimates of D-dimer accuracy for deep venous thrombosis or pulmonary embolism, and the clinical utility of this potentially important test remains unproved.

Accuracy of laboratory and portable monitor international normalized ratio determinations. Comparison with a criterion standard

BACKGROUND

Portable instruments that measure the prothrombin time and automatically calculate the international normalized ratio (INR) with the use of a drop of whole blood have simplified the treatment of patients who are receiving warfarin therapy. The accuracy of these portable monitors has never been determined by comparing INR results with a criterion (gold) standard INR determination.

METHODS

Duplicate whole-blood INR determinations were made with two commercially available portable INR monitors. Duplicate frozen-plasma samples were measured with four different thromboplastin reagents, each with a different international sensitivity index. The criterion standard INR was determined by using an international reference thromboplastin and the manual tilt-tube technique. Agreement was evaluated by determining how accurately laboratory and monitor INR determinations matched criterion standard values in designating a sample to be within or outside of currently recommended INR target ranges.

RESULTS

Two of the laboratory methods, which used relatively sensitive thromboplastins, showed close agreement with the criterion standard, whereas two laboratory methods that used less sensitive thromboplastin reagents showed poor agreement. Both of the portable monitors fell between these extremes. The two best laboratory methods ere significantly better (P < .003) than both monitors, which in turn were better (P < .003) than the remaining two laboratories.

CONCLUSIONS

There is large interlaboratory variation in the accuracy of INR determinations. Laboratory methods that used insensitive (high international sensitivity index) thromboplastins performed poorly. Accuracy of monitor measurements appears satisfactory.

Failure of the synthetic androgen, danazol, to increase protein S levels and prevent thrombosis in a patient with severe protein S deficiency

A 34-year-old man with recurrent deep and superficial thromboses was found to have severe protein S deficiency. Treatment with both warfarin and adjusted-dose subcutaneous heparin failed to completely prevent thrombosis. Based on reports of increases in the endogenous anticoagulants (protein C, protein S, antithrombin III and plasminogen) with synthetic androgen therapy, the patient was treated with danazol for 8 weeks. Although the levels of antithrombin III, protein C and plasminogen increased, no change in the levels of total or free protein S or C4b binding protein was observed. Treatment was discontinued at 8 weeks when the patient developed a recurrence of superficial thrombophlebitis. The role of synthetic androgens in the treatment of patients with inherited thrombotic disorders is reviewed and potential reasons for treatment failure in this patient are discussed.

Transfusion therapy in acquired coagulopathies

Acquired coagulopathies, such as are observed in patients with liver disease, uremia, and acute disseminated intravascular coagulation, are complex disorders usually involving a combination of deficiency of multiple coagulation factors, platelet dysfunction, and thrombocytopenia. Transfusion of specific blood products, such as fresh-frozen plasma, platelets, and cryoprecipitate, may be effective in the treatment and prevention of hemorrhage in patients with these disorders; however, the optimal regimens continue to be defined. Because the risks of virus transmission along with hemolytic and allergic reactions continue to accompany blood product transfusions, nontransfusional forms of treatment of acquired coagulopathies, such as desmopressin acetate, antifibrinolytic agents, and aprotinin, have assumed greater roles in the treatment of these hemostatic disorders. Much work remains to define better the most effective and safest approach to the treatment of the acquired coagulopathies.

Life-long bleeding diathesis: effect of orthotopic liver transplantation

Proper regulation of the fibrinolytic system is critical to the prevention of both thrombosis and hemorrhage. Patients with inherited or acquired excess fibrinolysis may have a bleeding tendency, usually characterized by delayed and posttrauma or postoperative bleeding. The liver plays many roles in this regulation, including the synthesis of plasminogen, alpha 2-antiplasmin (alpha 2-AP) and plasminogen activator inhibitor-1 (PAI-1), and the clearance of tissue-plasminogen activator (t-PA). Inherited deficiencies of alpha 2AP, PAI-1 and inherited excess t-PA associated with clinically significant bleeding have been reported. The authors describe a patient with a life-long bleeding diathesis who demonstrated evidence of excess t-PA. One of two daughters also had a bleeding tendency and demonstrated excess t-PA. The patient developed cirrhosis and underwent orthotopic liver transplantation. Following transplantation, all fibrinolytic parameters returned to normal, and the bleeding diathesis appeared to no longer exist. The effect of liver transplantation on this patient's fibrinolytic abnormalities and the effect of cirrhosis on this patient's laboratory evaluation are discussed.

Transient lupus anticoagulant associated with prothrombin deficiency: unusual cause of bleeding in a 5-year-old girl

PURPOSE

We present the association of a lupus anticoagulant with hypoprothrombinemia in a 5-year-old girl, who presented with ecchymoses and a hematoma. This coagulopathy should be included in the differential of bleeding in the previously healthy children.

PATIENTS AND METHODS

Coagulation and immunology laboratory evaluation was performed at the time of presentation with bleeding and 2 months later, after complete clinical recovery.

RESULTS

A 5-year-old girl presented with ecchymoses and a hematoma after after an upper respiratory illness. Laboratory evaluation showed prolongation of both the prothrombin time (PT) and activated partial thromboplastin time (aPTT) due to the presence of a strong lupus anticoagulant associated with a decreased level of prothrombin (15 U/dl). Hypocomplementemia was also detected. Bruising resolved spontaneously, and the PT and aPTT gradually normalized. Reevaluation 2 months later showed that the lupus anticoagulant had disappeared and the prothrombin deficiency was markedly improved.

CONCLUSIONS

This case demonstrates that transient lupus anticoagulants must be included in the differential for bleeding in young children. Also, in children with lupus anticoagulants, neither the association of hypoprothrombinemia nor the presence of evidence of activation of the immune system appears to predict whether a patient will have or develop systemic lupus erythematosus.

An autoantibody to human plasma prekallikrein blocks activation of the contact system

A patient without a history of bleeding or thromboembolism presented with an activated partial thromboplastin time (aPTT) of 55.1 s (normal 24-38 s). Incubation of the patient plasma with an equal volume of normal plasma failed to correct the aPTT, suggesting the presence of an inhibitor. The MRVVT (modified Russell Viper venom time) was normal, and the anti-cardiolipin antibody titres were not elevated, indicating that the presence of a lupus anticoagulant was unlikely. Plasma prekallikrein (PK) measured by a coagulant assay (2 U/dl) was very low, but PK was in the low normal range (approximately 65%) when measured by an enzymatic assay (amidolytic) or by an antigenic assay (ELISA). The purified patient IgG reacted with purified PK, the heavy chain, and the 28 kD fragment of the heavy chain, indicating that it contained an autoantibody to PK. The purified IgG did not directly inhibit the amidolytic activity of kallikrein, but it did inhibit the activation of PK to kallikrein by activated factor XII. Activation of the contact system by dextran sulphate, as reflected by the cleavage of HK on a Western blot, was inhibited when the patient IgG was added to pooled normal plasma. The antibody appears to be oligoclonal with IgG1 being most abundant, followed by IgG4. This report appears to be the first of a spontaneously occurring antibody to prekallikrein.

Plasmin modulates the thrombin-evoked calcium response in C6 glioma cells

Extracellular proteinases may be selectively targeted to cell surfaces by specific receptors or binding sites. In previous studies, we have characterized cellular binding sites for plasminogen and plasmin on rat C6 glioma cells. In this investigation, we studied the response of C6 cells to alpha-thrombin and plasmin by measuring the rapid kinetics of free intracellular Ca2+ concentrations ([Ca2+]i). Thrombin produced a strong, concentration-dependent rise in [Ca2+]i with an onset within 3 s and peak levels achieved in less than 10 s. A similar response was also evoked by an SFLLRN-containing thrombin-agonist peptide. C6 cells did not respond to plasmin (25 nM-1.5 microM). By contrast, pretreatment of C6 cells with 100 nM plasmin significantly inhibited the [Ca2+]i response to thrombin and the thrombin-agonist peptide. The peak [Ca2+]i response to thrombin, in cells pretreated with plasmin, was reduced by approx. 50%. The effect of plasmin on the cellular response to thrombin was selective, as pretreatment of the cells with plasmin did not affect the [Ca2+]i response to platelet-activating factor. Di-isopropylphosphorylplasmin and plasminogen did not inhibit the cellular response to thrombin, indicating that plasmin activity is required and that occupancy of cellular plasmin(ogen)-binding sites alone is insufficient. These studies demonstrate that plasmin does not directly induce a response in C6 cells, but may affect cellular function by specifically modulating the thrombin response.

Significant hyponatremia following DDAVP administration in a healthy adult

We report the development of significant hyponatremia (121 mEq/L) following three daily intravenous doses of desmopressin acetate (DDAVP; 18 micrograms; 0.3 micrograms/kg) in a healthy adult with moderate von Willebrand's disease. Previous reports suggest that clinically important hyponatremia due to DDAVP administration only occurs in the very young, those receiving hypotonic intravenous fluids or those given multiple frequent (e.g., every 8-12 hours) doses of DDAVP. None of these conditions was present in this case. Consideration should be given to monitoring serum sodium levels and fluid balance in patients receiving more than a single dose of DDAVP, even in the absence of previously reported risk factors for the development of hyponatremia.

Artifactual prolongation of the activated partial thromboplastin time mimicking a coagulopathy. A lesson relearned

A markedly prolonged activated partial thromboplastin time (APTT) was observed in a 61-year-old woman with bruising and a decreasing hematocrit. Coagulation laboratory evaluation was sought to determine the cause of the prolonged APTT and bleeding. Evaluation demonstrated that, rather than identifying a coagulopathy, the APTT prolongation was most likely artifactual. The APTT was actually very short. With a combination of a relatively strong activating APTT reagent (Dade Actin; Dade, Miami, FL) and a fixed lag phase in the automated coagulation instrument (16 seconds), the clot formed before the instrument began to read. Thus, during the period of observation (120 seconds), no change in optical density was observed. This was interpreted by the laboratory as "> 120 seconds." This case reminds those involved in the performance and interpretation of APTTs of the importance of a manual or visual method of verifying markedly prolonged APTTs.

Standardizing the prothrombin time. Calibrating coagulation instruments as well as thromboplastin

Recently, indications for anticoagulation with warfarin have increased, prothrombin time (PT) monitoring at offices and homes has become available, and the international sensitivity index (ISI) has been recognized as a means of adjusting for differences in thromboplastins to standardize warfarin sodium dosing. However, different coagulation instruments may yield differences in PTs even after correcting for the ISI by means of the international normalized ratio (INR) (INR = [PT measured ISI/PT normal]). Because the PTs and INRs from our Anticoagulation Clinic (portable PT monitor, ISI = 2.04, normal PT = 12.0 seconds) differed from the hospital reference laboratory (ISI = 2.01, normal PT = 12.0 seconds) despite nearly identical ISIs and equivalent control or normal PTs, we systematically compared the two systems. During a 3-month period, we studied two groups of 50 consecutive patients who had been receiving a stable dose of warfarin. After a single venipuncture, PTs and INRs were measured independently, and regression lines were calculated. Within each group, the results from the different instruments were not identical, but they were highly correlated. In comparing INRs, the regression lines for the separate and combined groups were as follows: group 1 monitor INR = 0.49 reference INR + 0.81, r = .94; group 2 monitor INR = 0.57 reference INR + 0.86, r = .88; and combined monitor INR = 0.49 reference INR + 0.95, r = .89. Only 82% of the differences for all samples were within 1.0 INR units. We concluded that the instrumentation effect may be clinically meaningful, and coagulation instruments as well as thromboplastins should be calibrated to standardize warfarin therapy.

Vaginal telangiectasias: unusual presentation of the Osler-Weber-Rendu syndrome

BACKGROUND

The Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia) is an autosomal dominant disorder of blood vessels associated with mucocutaneous telangiectasis and arteriovenous malformations of internal organs.

CASE

A 23-year-old woman was found on routine gynecologic examination to have asymptomatic vaginal telangiectasias, a previously unreported initial site of involvement in this syndrome.

CONCLUSION

The finding of asymptomatic vaginal telangiectasias on routine pelvic examination should alert the clinician to the possibility of the Osler-Weber-Rendu syndrome.

Binding of anisoylated Lys-plasminogen streptokinase activator complex to cells in culture

Anisoylated Lys-plasminogen streptokinase activator complex (APSAC) was purified from Eminase by chromatography on Superose-12. Purified APSAC did not significantly deacylate within 4 h at 4 degrees C in solution as determined by hydrolysis of D-Val-L-leu-L-lys-p-nitroanilide HCl (S-2251). At 37 degrees C, maximum amidase activity developed in 120 min; epsilon-amino-n-caproic acid (EACA) did not affect the apparent rate of APSAC deacylation but stabilized the streptokinase-plasmin(ogen) complex (SkPl) which formed. APSAC bound to C6 glioma cells and human umbilical vein endothelial cells (HUVECs) in culture. Binding as completely inhibited by EACA suggesting an essential role for the plasminogen kringle domains. Cell-associated APSAC deacylated to form active SkPl which hydrolyzed S-2251 and D-Val-Leu-Lys-7-amino-4-methyl coumarin. The rate of APSAC deacylation was increased when the APSAC was cell-associated. APSAC that was initially bound to C6 cells or HUVECs also activated 125I-plasminogen. This activity may have reflected cell-associated APSAC or APSAC but dissociated into solution. Plasmin was recovered bound to cells and in solution. These studies demonstrate that APSAC associates with cell-surfaces and retains activity. In the circulation, cell-surfaces may provide a significant pharmacologic compartment for intravenously administered APSAC.

Acquired antithrombin III deficiency: replacement with antithrombin III concentrates in a patient with protein S deficiency accelerates response to therapy

A 33-year-old man with inherited protein S deficiency and a 20-year history of deep and superficial venous thrombosis was admitted for treatment of extensive, acute, superficial venous thrombosis of the left lower extremity. Clinical response to intravenous heparin was very slow. After discovery of acquired antithrombin III deficiency superimposed on the protein S deficiency, he was given antithrombin III concentrates with the intravenous heparin. His response to therapy was accelerated. The development of acquired antithrombin III deficiency in patients with venous thrombosis may slow the response to standard anticoagulant therapy. Therapy of the thrombosis may be improved with administration of antithrombin III concentrates.

Fibrinogenolytic and fibrinolytic activity of cell-associated plasmin

Binding of plasmin(ogen) to rat C6 glioma cells is saturable and kringle-domain dependent. This interaction was studied as a model of plasmin(ogen) receptor interactions in nucleated mammalian cells. Apparent 125I-plasmin dissociation from C6 cell binding sites was slow; however, the dissociation rate was increased when the solution contained diisopropyl phosphoryl-plasmin (0.3 microM), fibrinogen (0.16 or 0.8 mg/ml), 1.08 mM D-Val-L-Leu-L-Lys-p-nitroanilide-HCl (S-2251), or epsilon-amino-n-caproic acid (EACA, 5.0 mM). EACA promoted the most rapid dissociation of plasmin. C6 cell-associated plasmin and plasmin in solution demonstrated similar amidase activity. Only specifically bound plasmin (75% of total binding) was active against S-2251. Plasmin that was initially bound to C6 cells digested fibrinogen in a time- and plasmin concentration-dependent manner. alpha 2-Antiplasmin (alpha 2AP, 0.1 microM) completely inhibited fibrinogenolysis by plasmin that was initially C6- or human umbilical vein endothelial-cell associated. Since alpha 2AP reacts selectively with plasmin in solution (minimally with plasmin bound to cells), fibrinogen digestion by cell-associated plasmin probably occurred only after the plasmin dissociated into solution. Crosslinked fibrin clots were formed in uniform layers over C6 cells. If the cells were incubated with plasmin before addition of fibrinogen and thrombin, the clots were rapidly lysed. alpha 2AP incompletely inhibited fibrinolysis when added after fibrin polymerization (44% inhibition with 0.1 microM alpha 2AP). Fibrinolysis was completely inhibited when alpha 2AP was added before fibrin polymerization. These studies suggest that plasmin must first dissociate from cellular binding sites to mediate fibrinogenolysis or fibrinolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Fatal disseminated Conidiobolus coronatus infection in a renal transplant patient

A case of fatal disseminated fungal infection due to Conidiobolus coronatus in a patient with a renal transplant is described. This organism, known to cause localized infections in otherwise healthy individuals in the tropics, is now recognized as a cause of fatal infection in immunosuppressed hosts. Histologically, localized infections are characterized by lack of vessel invasion and the presence of an eosinophilic sleeve around fungal elements, called the Splendore-Hoeppli phenomenon. The histologic findings in the present case were more typical of mucormycosis, and the correct diagnosis was established only after the organism was isolated and identified in culture.

Atherosclerosis and unstable angina in Bernard-Soulier syndrome

Platelets and von Willebrand factor play pathogenetic roles in atherosclerosis and acute coronary artery ischemic syndromes. Patients with Bernard-Soulier Syndrome are deficient in several platelet membrane glycoproteins, including glycoprotein Ib (GpIb). Glycoprotein Ib is the primary platelet receptor for von Willebrand factor and plays a critical role in the initiation of thrombus formation. Glycoprotein Ib, but also GpIIb/IIIa, mediates the adhesion of platelets to damaged endothelium, particularly at the high shear stresses found in small or diseased arteries. A patient with Bernard-Soulier syndrome is described who developed coronary artery atherosclerosis and unstable angina requiring coronary artery bypass grafting. The implications of this experiment in nature on the contribution of platelets and platelet GpIb and GpIIb/IIIa receptors to the development of atherosclerosis and unstable angina are discussed.

Anemia of renal failure. Use of erythropoietin

Chronic renal failure is almost invariably accompanied by symptomatic anemia. It has been demonstrated that the primary cause of this anemia is inadequate production of erythropoietin by the diseased kidneys. The isolation of erythropoietin, followed by the cloning and expression of the human erythropoietin gene, made possible clinical trials of rHuEPO in uremic patients. rHuEPO produced dramatic increases in the hematocrit in almost all patients treated and also ameliorated many symptoms, such as lethargy, dizziness, and poor appetite, that had long been attributed to the effect of uremic toxins. Adverse effects of treatment with rHuEPO noted in the early clinical trials included hypertension, seizures, arteriovenous fistula or shunt thrombosis, and hyperkalemia. Further study of rHuEPO has shown that many of these side effects may be no more frequent in patients receiving rHuEPO than in other uremic patients not receiving rHuEPO. Reduction of the rHuEPO dosage and subcutaneous administration produce less rapid increases in the hematocrit and may lessen the incidence and severity of these side effects. rHuEPO therapy places great demands on both the body's iron stores and the capacity to rapidly transfer iron from storage sites to the erythroid progenitor cells. Thus, almost all patients treated with rHuEPO become iron deficient and require oral or parenteral iron replacement. Response to rHuEPO in uremic patients is diminished if the anemia is complicated by iron deficiency, inflammatory disorders, aluminum overload, or deficiency of folate or vitamin B12. rHuEPO therapy is safe and effective in the treatment of the anemia of chronic renal failure. The use of rHuEPO leads to enhanced quality of life and eliminates the need for red cell transfusions. In addition to hemodialysis patients, predialysis patients and those on CAPD benefit from and are candidates for rHuEPO therapy.