[Evaluation of an education program of patients undergoing oral anticoagulation treatment]

OBJECTIVE

To evaluate the therapeutic impact of an education program on patients undergoing oral anticoagulation treatment, within the hospital of Annecy (France).

MATERIAL AND METHODS

Groups of 10 patients were invited to participate to two meetings. The education was carried out by two nurses. Thanks to this prospective study, we compare the population before and after education in terms of treatment knowledge and stability.

RESULTS

Within 9 months 88 patients have been included, amongst which 55 have attended the two meetings. The average of correct answers to the knowledge evaluation questionnaire distributed before and after 6 months of education were, respectively, 6.63/12, 10.09/12 (P < 0.0001). Through INR controls within the 6 months preceding (424 controls) and the 6 months following the education (619 controls), we observe: an increase of the total INR average in therapeutic zone, from 45% to 61% (P < 0.0001); a decrease of the difference average per patient between the INR value observed and the one targeted: 0.54 before education, 0.40 after education (P = 0.0016); at last, the average phasing per patient under the therapeutic zone increases after education, from 49% to 65% (P < 0.001).

CONCLUSION

The education improves objectively the knowledge of patient undergoing AVK. If the size of patient sample is not large enough to prove any consequence on hemorrhagic or thrombotic complications, the education program still improves significantly the treatment stability.

A psychometric analysis of the Needs Assessment Checklist (NAC)

DESIGN

Consecutive series, psychometric validation study.

OBJECTIVE

To evaluate the psychometric reliability and validity of a clinically focused measure of rehabilitation outcome, known as the Needs Assessment Checklist (NAC).

SETTING

Tertiary care, spinal cord injury centre (National Spinal Injuries Centre), Stoke Mandeville Hospital, UK.

PARTICIPANTS

In total, 43 spinal cord injured (SCI) in-patients (38 male and five female). During this study all patients actively participated in a comprehensive, multidisciplinary Goal Planning and Needs Assessment Rehabilitation Programme.

INTERVENTION

Test-retest and concurrent assessment, conducted in one administration, within a week of routine clinical assessment. Reliability analyses were performed examining the NAC's internal consistency, test-retest reliability, and concurrent validity.

MAIN OUTCOME MEASURES

The NAC is a rehabilitation outcome measure, specifically developed for the SCI population, which is used to assess patient attainment in core rehabilitation areas at mobilisation and prior to discharge. The Spinal Cord Independence Measure (SCIM) and Hospital Anxiety and Depression Scale (HADS) were also employed as comparable benchmark assessment measures with established psychometric properties. Patient comments were gained during this administration, rating the NAC with regard to its usefulness, clarity, and personal relevance.

RESULTS

Reliability analyses yielded high internal consistency coefficients (mean alpha = 0.8587, SD = 0.918). All subscales performed above the specified level (0.7). The mean item-internal validity correlation for NAC subscales was 0.5921 (SD = 0.1411). Test-retest correlations ranged between 0.694 (Bladder Management) and 0.904 (Skin Management) (P < or = 0.01). The mean percentage of agreement between clinical and test-retest assessment over all NAC subscales was 75.5% (SD = 5.01%). Concurrent validity analyses correlating individual subscale scores with SCIM and HADS subscales produced high correlations between 0.850 (Activities of Daily Living with SCIM Self-Care, P < or = 0.01) and -0.466 (Psychological Issues with HADS-Depression, P < or = 0.01). Significant differences were identified between injury category within NAC subscales; however, this was not consistent. The NAC achieved high patient ratings, attaining mean ratings of seven (out of 10) for usefulness, and eight for its clarity and personal relevance.

CONCLUSION

The findings of this study indicate that the NAC is a psychometrically reliable and valid clinical measure of rehabilitation outcome.

N-terminal pro B type natriuretic peptide, but not the new putative cardiac hormone relaxin, predicts prognosis in patients with chronic heart failure

OBJECTIVE

To determine whether the plasma concentration of the putative new cardiac hormone relaxin is predictive of clinical outcome in patients with chronic heart failure (CHF).

DESIGN

Plasma relaxin and N-terminal pro B type natriuretic peptide (NT pro BNP) concentrations were measured in 87 patients admitted in an emergency with CHF caused by left ventricular systolic dysfunction. These were related to death and death or readmission with CHF over the following year.

SETTING

Western Infirmary, Glasgow, UK.

MAIN OUTCOME MEASURES

Plasma concentrations of relaxin and NT pro BNP; time to death or hospitalisation caused by heart failure.

RESULTS

Plasma concentrations of both relaxin and NT pro BNP were greatly increased. Of the 43 patients with NT pro BNP above the group median concentration, 23 (53%) died and 30 (70%) died or were hospitalised with CHF. Among the 44 with concentrations below the median, these numbers were 5 (11%) and 12 (27%), respectively (p < 0.0001 and p < 0.0001, respectively). Plasma NT pro BNP concentration remained an independent predictor of an adverse clinical outcome in a multivariate analysis. Of the 42 patients with a relaxin concentration above the median, 13 (31%) died and 20 (48%) died or were hospitalised. Below the median, these numbers were 15 of 45 (33%) and 22 of 45 (49%) (p = 0.76 and p = 0.84, respectively).

CONCLUSIONS

NT pro BNP is a powerful and independent predictor of outcome in CHF, whereas relaxin, also secreted by the heart in increased amounts in CHF, is not.

Functional outcomes of pediatric liver transplantation

The functional status and health-related quality of life (HRQOL) of children who survive liver transplantation (LT) have not been well documented. The purpose of this study was to determine the functional status and HRQOL in this population using a validated measure for children, the Child Health Questionnaire-Parent Form 50 (CHQ-PF50).

METHODS

The CHQ-PF50 instrument was completed by the parents of 55 children who agreed to participate in a mailing survey. Subscale scores for the sample were compared with those of a published normal population (n = 391).

RESULTS

Study sample characteristics were: 87% Caucasian, 54.5% female, mean age at survey was 9.6 years (range, 5-17 years). Responding caregivers were 95% biologic parents and 93% female. Compared with the normal population, LT recipients had lower subscale scores for general health perceptions (P < 0.0005), emotional impact on parents (<0.0005) and disruption of family activities (0.0005). The mean physical summary score of the LT recipients was lower than that of the normal population 48.1 +/- 12.1 (P = 0.005), but the mean psychosocial summary score was similar 48.8 +/- 11.9 (P = 0.156). Within the LT population, the original diagnosis (biliary atresia vs. other), type of LT (living donor vs. cadaveric), age at LT, z score for height, and hospital days did not significantly influence any of the subscale scores.

CONCLUSIONS

Children who have survived LT have functional outcomes in the physical domain that are lower than those of normal children. Self-esteem and mental health in this group appeared normal. The parents in this sample experienced more emotional stress and disruption of family activities than did parents in a normal population.

Comparative analysis of goal achievement during rehabilitation for older and younger adults with spinal cord injury

OBJECTIVE

To evaluate rehabilitation outcome in a representative sample of older and younger SCI patients.

DESIGN

Case series, consecutive sample, survey.

SETTING

Tertiary care, spinal cord injury unit (National Spinal Injuries Centre), Stoke Mandeville Hospital.

PARTICIPANTS

One hundred and forty-seven male and 45 female newly injured in-patients (consisting of 152 younger adults, age range=16 to 54, and 40 older adults, age range=55 to 85) admitted between 1995 and 1999.

INTERVENTION

All patients were actively participating in a comprehensive, multidisciplinary Goal Planning and Needs Assessment rehabilitation programme.

MAIN OUTCOME MEASURE

The Needs Assessment Checklist. Specifically designed and developed for the spinal cord injured population, this clinical assessment tool provides a way of assessing and ensuring that rehabilitation programmes are geared toward each patient's individual needs, providing the patient with the skills appropriate to their level of lesion. As part of ongoing psychometric analyses of the Needs Assessment Checklist, internal consistency reliability coefficients are reported for this measure.

RESULTS

The type and cause of injury for the older adult group in this study was comparable with previous research. Older adults' rehabilitation gains were comparable to those of the younger age group. Younger adults were more mobile initially after their injury. However, when the two groups were matched for injury characteristics etc. the only differences in final outcome between older and younger adults were in skin management ability. Both groups showed significant improvements in all areas of need in the period between mobilisation and entering the pre-discharge ward.

CONCLUSION

These results highlight important considerations for the rehabilitation of older adults and emphasise the need for active, individually tailored rehabilitation programmes. There are specific areas of need (i.e. skin management) where older adults do not achieve comparable levels of independence. Special attention needs to be paid to the problems presented by SCI older adults and efforts should be made to better prepare rehabilitation professionals to adapt to age specific differences.

Recent advances in angiotensin II signaling

Angiotensin II (Ang II) is a multifunctional hormone that influences the function of cardiovascular cells through a complex series of intracellular signaling events initiated by the interaction of Ang II with AT1 and AT2 receptors. AT1 receptor activation leads to cell growth, vascular contraction, inflammatory responses and salt and water retention, whereas AT2 receptors induce apoptosis, vasodilation and natriuresis. These effects are mediated via complex, interacting signaling pathways involving stimulation of PLC and Ca2+ mobilization; activation of PLD, PLA2, PKC, MAP kinases and NAD(P)H oxidase, and stimulation of gene transcription. In addition, Ang II activates many intracellular tyrosine kinases that play a role in growth signaling and inflammation, such as Src, Pyk2, p130Cas, FAK and JAK/STAT. These events may be direct or indirect via transactivation of tyrosine kinase receptors, including PDGFR, EGFR and IGFR. Ang II induces a multitude of actions in various tissues, and the signaling events following occupancy and activation of Ang receptors are tightly controlled and extremely complex. Alterations of these highly regulated signaling pathways may be pivotal in structural and functional abnormalities that underlie pathological processes in cardiovascular diseases such as cardiac hypertrophy, hypertension and atherosclerosis.

Studies on the putative interactions between the organophosphorus insecticide Phosmet and recombinant mouse PrP and its implication in the BSE epidemic

It has been suggested that exposure of cattle to the ectoparasiticide Phosmet in the 1980s caused a conformational change in the cellular prion protein (PrP(C)) to form the BSE prion (PrP(SC)), which initiated the epidemic of bovine spongiform encephalopathy (BSE). Recombinant mouse cellular prion (r[mouse]PrP(C)) was exposed to the organophosphorus pesticide Phosmet in vitro and the conformation of the prion before and after exposure was monitored using circular dichroism (CD) spectroscopy, utilizing synchrotron radiation at the Council for the Central Laboratory of the Research Councils (CLRC) facilities at Daresbury, UK. Metabolites of Phosmet, generated in situ by rat microsomes, were investigated in the same way, to determine whether they might initiate the conformational change due to their high chemical reactivity. Our studies showed that exposure of r[mouse]PrP(C) to Phosmet or microsomes-generated metabolites of Phosmet did not result in the conformational change in the protein from alpha-helix to beta-pleated sheet that is characteristic of the PrP(C) to PrP(SC) conversion and, therefore, Phosmet is very unlikely to have initiated the BSE epidemic by a simple direct mechanism of conformational change in the prion protein.

"Diastolic heart failure" or heart failure caused by subtle left ventricular systolic dysfunction?

OBJECTIVES

To determine whether patients with suspected heart failure but preserved systolic function, as determined by conventional echocardiographic measures (often said to have "diastolic heart failure), might have subtle left ventricular systolic dysfunction detectable by a new measure of left ventricular systolic function-left ventricular systolic atrioventricular plane displacement.

DESIGN

Observational study.

SETTING

Direct access echocardiography.

PATIENTS

147 patients with suspected heart failure referred by general practitioners.

MEASUREMENTS

Echocardiographic assessment of conventional measures of left ventricular systolic function (fractional shortening, ejection fraction (by Simpson's biplane method) and "eyeball" assessment) and measurement of left ventricular systolic atrioventricular plane displacement.

RESULTS

Between 21% and 33% of patients with "normal" left ventricular systolic function by conventional methods were found to have abnormal left ventricular systolic atrioventricular plane displacement.

CONCLUSIONS

Approximately one quarter of patients with suspected heart failure but preserved systolic function by conventional methods have abnormal atrioventricular plane displacement. These patients with suspected heart failure but preserved systolic function by conventional echocardiographic measures may have heart failure caused by subtle systolic dysfunction rather than isolated "diastolic heart failure".

Angiotensin receptors: signaling, vascular pathophysiology, and interactions with ceramide

Angiotensin II (ANG II) is a pleiotropic vasoactive peptide that binds to two distinct receptors: the ANG II type 1 (AT(1)) and type 2 (AT(2)) receptors. Activation of the renin-angiotensin system (RAS) results in vascular hypertrophy, vasoconstriction, salt and water retention, and hypertension. These effects are mediated predominantly by AT(1) receptors. Paradoxically, other ANG II-mediated effects, including cell death, vasodilation, and natriuresis, are mediated by AT(2) receptor activation. Our understanding of ANG II signaling mechanisms remains incomplete. AT(1) receptor activation triggers a variety of intracellular systems, including tyrosine kinase-induced protein phosphorylation, production of arachidonic acid metabolites, alteration of reactive oxidant species activities, and fluxes in intracellular Ca(2+) concentrations. AT(2) receptor activation leads to stimulation of bradykinin, nitric oxide production, and prostaglandin metabolism, which are, in large part, opposite to the effects of the AT(1) receptor. The signaling pathways of ANG II receptor activation are a focus of intense investigative effort. We critically appraise the literature on the signaling mechanisms whereby AT(1) and AT(2) receptors elicit their respective actions. We also consider the recently reported interaction between ANG II and ceramide, a lipid second messenger that mediates cytokine receptor activation. Finally, we discuss the potential physiological cross talk that may be operative between the angiotensin receptor subtypes in relation to health and cardiovascular disease. This may be clinically relevant, inasmuch as inhibitors of the RAS are increasingly used in treatment of hypertension and coronary heart disease, where activation of the RAS is recognized.

Permeabilization of model lipid membranes by Bacillus sphaericus mosquitocidal binary toxin and its individual components

The high larvicidal effect of Bacillus sphaericus (Bs), a mosquito control agent, originates from the presence of a binary toxin (Bs Bin) composed of two proteins (BinA and BinB) that work together to lyse gut cells of susceptible larvae. We demonstrate for the first time that the binary toxin and its individual components permeabilize receptor-free large unilamellar phospholipid vesicles (LUVs) and planar lipid bilayers (PLBs) by a mechanism of pore formation. Calcein-release experiments showed that LUV permeabilization was optimally achieved at alkaline pH and in the presence of acidic lipids. BinA was more efficient than BinB, BinB facilitated the BinA effect, and their stoichiometric mixture was more effective than the full Bin toxin. In PLBs, BinA formed voltage-dependent channels of approximately 100-200 pS with long open times and a high open probability. Larger channels (> or =400 pS) were also observed. BinB, which inserted less easily, formed smaller channels (< or =100 pS) with shorter mean open times. Channels observed after sequential addition of the two components, or formed by their 1:1 mixture (w/w), displayed BinA-like activity. Bs Bin toxin was less efficient at forming channels than the BinA/BinB mixture, with channels displaying the BinA channel behavior. Our data support the concept of BinA being principally responsible for pore formation in lipid membranes with BinB, the binding component of the toxin, playing a role in promoting channel activity.

Electrical cardioversion for atrial fibrillation: outcomes in "real-life" clinical practice

BACKGROUND

There is currently considerable debate with regard to the optimal management of atrial fibrillation/flutter (AF), including the long-term success of electrical cardioversion and the duration of anti-coagulation thereafter. The aim of this study was to investigate the current management and outcomes of electrical cardioversion in unselected patients in ordinary clinical practice.

METHODS

A prospective, observational study of 111 consecutive patients with AF who had been referred for electrical cardioversion was undertaken in a large teaching hospital. After cardioversion, patients were followed-up for 12 months or until death if this occurred earlier.

RESULTS

Sinus rhythm was restored immediately in 96 of 111 (86%) patients. Only 54 of 88 (61%) patients in sinus rhythm at discharge remained in this rhythm at 1 month. Of these 54, a further 21 (39%) had relapsed into AF by 12 months. Independent predictors of sinus rhythm at discharge were younger age (for a difference of 5 years, odds ratio=1.54; 95% confidence interval 1.04 to 1.16; P=0.002) and absence of hypertension (1.73, 1.22-1.91; P=0.015). The presence of sinus rhythm at discharge (6.4, 1.6-25.3; P=0.007) was an independent predictor of sinus rhythm at 1 month, whereas older age was a negative predictor (0.96, 0.92-1.0; P=0.05). Health-related quality of life improved at 1 and 12 months in those patients who remained in sinus rhythm compared to those who remained in AF.

CONCLUSIONS

Though electrical cardioversion for AF has a high initial success rate only a minority of patients remained in sinus rhythm 1 year. The common practice of discontinuing anticoagulant treatment in patients in sinus rhythm at 1 month may be unsafe. Long-term maintenance of sinus rhythm is, however, associated with better health-related quality of life.

Aspartic proteases of Plasmodium falciparum and other parasitic protozoa as drug targets

All parasitic protozoa contain multiple proteases, some of which are attracting attention as drug targets. Aspartic proteases are already the targets of some clinically useful drugs (e.g. chemotherapy of HIV infection) and a variety of factors make these enzymes appealing to those seeking novel antiparasite therapies. This review provides a critical analysis of the current knowledge on Plasmodium aspartic proteases termed plasmepsins, proposes a definitive nomenclature for this group of enzymes, and compares these enzymes with aspartic proteases of humans and other parasitic protozoa. The present status of attempts to obtain specific inhibitors of the parasite enzymes that will be useful as drugs is outlined and suggestions for future research priorities are proposed.

Functional characterization of alpha1-adrenoceptor subtypes in human subcutaneous resistance arteries

The functional characteristics of the alpha1-adrenoceptor subtypes in human resistance arteries are still not clear. We recently reported that the alpha1A-adrenoceptor predominantly mediates contraction to norepinephrine in human skeletal muscle resistance arteries. In this study we extended these investigations to human subcutaneous resistance arteries. Arterial segments were isolated from the inguinal subcutaneous fat and mounted on a small vessel wire myograph. Potencies of agonists and antagonists were examined. N-[5-(4,5-dihydro-1H-imidazol-2yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl]methanesulphonamide (A-61603) was found to be 10- and 54-fold more potent than norepinephrine and phenylephrine, respectively. Brimonidine (UK 14304) evoked significantly smaller contractile responses than norepinephrine and phenylephrine, showing the presence of a small population of alpha2-adrenoceptors in these arteries, and this was confirmed by the studies with selective alpha1- and alpha2-adrenoceptor antagonists prazosin and (8aR,12aS,13aS)-5,8,8a,9,10,11,12,12a,13a-decahydro-3-methoxyl-12-(ethylsulphonyl)-6H-isoquino[2,1-g][1,6]-naphthyridine (RS 79948). Prazosin, 5-methyl-urapidil, and 2-[2,6-dimethoxyphenoxyethyl]aminomethyl)-1,4-benzodioxane (WB 4101) shifted the potency of norepinephrine concentration dependently giving pA2 values of 9.4, 8.9, and 10.1, respectively, showing the presence of the alpha1A-subtype in these arteries. Pretreatment with 1 and 10 microM chloroethylclonidine did not affect the potency of and maximum responses to norepinephrine, ruling out the presence of the alpha1B-subtype in these arteries. 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione (BMY 7378, 10 and 100 nM) did not affect the potency of norepinephrine but a small shift was observed by 1 microM BMY 7378, giving a pK(B) value of 7.1, much less than that reported for the alpha1D-subtype. These results suggest the predominant involvement of alpha1A-adrenoceptor in the contractile responses to norepinephrine in these arteries. The physiological role of this subtype in the maintenance of peripheral arterial resistance is yet to be confirmed.

Economics of chronic heart failure

Chronic heart failure (CHF) is now recognized as a major and escalating public health problem. The costs of this syndrome, both in economic and personal terms, are considerable. The prevalence of CHF is 1-2% and appears to be increasing, in part because of ageing of the population. Economic analyses of CHF should include both direct and indirect costs of care. Healthcare expenditure on CHF in developed countries consumes 1-2% of the total health care budget. The cost of hospitalization represents the greatest proportion of total expenditure. Optimization of drug therapy represents the most effective way of reducing costs. Recent economic analyses in the Netherlands and Sweden suggest the costs of care are rising.

Fatty acid status of women of reproductive age

OBJECTIVE

Healthy foetal and infant development is dependent on an adequate maternal supply of essential and polyunsaturated fatty acids (PUFA). While there are published data on the fatty acid status of pregnant women, there are few on the status of non-pregnant women of reproductive age. The aims of this study were to test the hypotheses that the fatty acid status of non-pregnant women is affected by socio-economic status and anthropometric, behavioural and obstetric factors.

DESIGN

Observational study

METHODS

One-hundred and thirty-five women of child-bearing age (mean 29.8 y, s.d. 6.92) were invited to provide a blood sample and to answer a questionnaire, of whom 114 were included in the study. Plasma and red cell total fatty acids were measured as their methyl esters by gas chromatography mass spectrometry.

RESULTS

On multivariate analyses, use of hormonal contraception was independently associated with lower plasma polyunsaturated fatty acids (difference between means -2.76, 95% confidence interval (-4.64, -0.88), P=0.0034), whereas cigarette smoking was associated with higher red cell oleic acid (0.74 (0.18, 1.29), P=0.0094). Fish intake was associated with higher red cell total n-3 fatty acids (0.62 (0.27, 0.85), P=0.0014).

CONCLUSIONS

We have reported data on the range of the fatty acids of plasma and red blood cells (RBC) total lipids of 114 healthy women of reproductive age. These data provide further information on how socio-economic, anthropometric, behavioural and obstetric factors may be relevant to female and nutrition and health.

SPONSORSHIP

University of Glasgow.

Validation of the Crisis in Family Systems-Revised, a contemporary measure of life stressors

The objectives of this study were to establish the validity of the Crisis in Family Systems-Revised, a recently developed measure of contemporary life stressors, using the same validation technique as in the original validation and to provide further evidence of construct validity by assessing its relationship to socioeconomic status and residential location. We conducted 124 in-person interviews with parents in three outpatient pediatric asthma clinics affiliated with an academic medical center. The design was cross-sectional and correlational. Total count of life stressors accounted for 19% of the variance in scores on the Center for Epidemiologic Studies-Depression. Respondents using Medicaid and living in the city experienced more objective stressors, but the proportions of stressors rated as negative or positive (Valence), and ongoing (Chronicity) were fairly constant across subsamples, as was the Difficulty rating. Psychologists and health and mental health services researchers are in need of constructs relevant to contemporary society and its issues and tools to measure these constructs. Life stressors appears to be such a construct and the Crisis in Family Systems-Revised a measure with considerable utility.

Serious adverse events experienced by patients with chronic heart failure taking spironolactone

In patients with chronic heart failure, spironolactone added to conventional treatment may lead to serious and, occasionally, fatal hyperkalaemia. In some cases this seems to happen because spironolactone causes diarrhoea. Four cases involving men with New York Heart Association functional class III heart failure are presented. As these cases revealed, close monitoring of blood chemistry is mandatory after starting spironolactone, and patients should be advised to stop spironolactone immediately if diarrhoea develops.

The frequency of homozygous deletion of a developmentally regulated Vh gene (Humhv3005) is increased in patients with chronic idiopathic thrombocytopenic purpura

Little is known of the genetic factors that may contribute to the development of chronic idiopathic thrombocytopenic purpura (cITP). We have previously shown that a developmentally regulated Vh gene (Humhv3005) is absent in 10/41 (24%) of patients with systemic lupus erythematosus while it is absent in only 7/88 (8%) of normal controls. This finding suggests that a homozygous deletion of an Ig variable (V) gene may alter the immune system and thus predispose the host to an autoimmune disorder. We have analyzed the same gene in 44 patients with cITP and found that Humhv3005 and like genes were absent in a higher percentage of patients (14 of 44, 31.8%) than they were absent in either normals (7/88, 8%, p = 0.002) or thrombocytopenic patients without cITP (6/53, 11.3%, p = 0.042); the hv3005 deletion frequency in the latter group did not differ from that in normals (P = 0.74). These data suggest that deletions of Humhv3005 and/or highly homologous Vh genes may predispose individuals to the development of cITP, and may contribute toward production of pathogenic antiplatelet antibodies.

Effects of urotensin II in human arteries and veins of varying caliber

BACKGROUND

-Urotensin II (UII) is the ligand for the GPR14 receptor and the most potent vasoconstrictor in the cynomolgus monkey. UII also contracts rat thoracic aorta. We studied the effect of human UII (hUII) in human blood vessels Methods and Results-Small subcutaneous resistance arteries, internal mammary arteries, saphenous veins, and small subcutaneous veins were studied using standard techniques. Subcutaneous resistance arteries constricted in response to norepinephrine (maximum tension, 2.84+/-0.38 mN/mm; the concentration required to produce 50% of the maximum response [EC(50)], 0.52+/-0.07 micromol/L) and endothelin-1 (maximum tension, 4.19+/-0.93 mN/mm; EC(50), 1.6+/-0.1 nmol/L). hUII did not contract these arteries, internal mammary arteries, or either type of vein, but it was a potent vasoconstrictor in rat thoracic aorta (maximum tension, 2.36+/-0.2 mN/mm; EC(50), 1.13+/-0.36 nmol/L).

CONCLUSIONS

-hUII has no vasoconstrictor action in human arteries and veins of different sizes and vascular beds. Marked species differences in the actions of UII question its importance in human cardiovascular regulation.

A calreticulin-like molecule from the human hookworm Necator americanus interacts with C1q and the cytoplasmic signalling domains of some integrins

Calreticulin was recently identified as a hookworm (Necator americanus) allergen, implying secretion, and contact with cells of the immune system, or significant worm attrition in the tissues of the host. As human calreticulin has been shown to bind to and neutralize the haemolytic activity of the complement component C1q, and to be putatively involved in integrin-mediated intracellular signalling events in platelets, it was of interest to determine whether a calreticulin from a successful nematode parasite of humans, with known immune modulatory and antihaemostatic properties, exhibited a capacity to interfere with complement activation and to interact with integrin domains associated with cell signalling in platelets and other leucocytes. We can now report that recombinant calreticulin failed to demonstrate significant calcium binding capacity, which is a hallmark of calreticulins in general and may indicate inappropriate folding following expression in a prokaryote. Nevertheless, recombinant calreticulin retained sufficient molecular architecture to bind to, and inhibit the haemolytic capacity of, human C1q. Furthermore, recombinant calreticulin reacted in surface plasmon resonance analysis (SPR) with peptides corresponding to cytoplasmic signalling domains of the integrins alphaIIb and alpha5, in a calcium independent manner. SPR was also used to ratify the specificity of a polyclonal antibody to hookworm calreticulin, which was then used to assess the stage specificity of expression of the native molecule (in comparison with reverse transcriptase-polymerase chain reaction), to indicate its apparent secretion, and to purify native calreticulin from worm extracts by affinity chromatography. This development will allow the functional tests described above to be repeated for native calreticulin, to ascertain its role in the host-parasite relationship.