[Analysis of nasal and exhaled nitric oxide concentration in nasal polyposis]

Nitric oxide (NO) is implicated in the pathophysiology of inflammatory airway diseases. It has been identified as a potential marker of airway inflammation.

OBJECTIVE

The purpose of the study was to assess the concentrations of nasal NO in upper and lower airways in nasal polyposis patients.

PATIENTS

18 nasal polyposis patients (14 men, 4 women) and 21 control subjects (7 men, 14 women), all non asthmatic non smokers, without respiratory infections were prospectively studied.

METHODS

They included nasal obstruction scoring, nasal endoscopic grading, allergy testing, nasal cytology, flow-volume spirometry and measurement of nasal (NNO) and exhaled NO (ENO) concentrations. NO was measured by a chemiluminescence NO Analyser (Sievers 280). NNO was analysed by aspiration with a constant flow of 3 l/mn. ENO was analysed during a slow expiration (50 ml/s) against a constant resistance of 10 cm H2O.

RESULTS

NNO was significantly (p<0,001) decreased in NP group (596.4 +/- 102.06 ppb) compared to control group (2 251.6 +/- 288.6 ppb). ENO was significantly (p<0.05) increased in NP group (45.4 +/- 14.1 ppb) compared to control group (11.2 +/- 1.16 ppb). NNO and ENO were not significantly different between atopic and non-atopic NP patients. NNO concentrations was inversely correlated with the values of nasal endoscopic grading. No correlation was found between NNO concentrations and respectively nasal obstruction scoring and eosinophil count in nasal mucosa.

CONCLUSION

Further studies are necessary to understand the pathophysiology of decreasing NNO and increasing ENO in nasal polyposis. In particular, ENO could be consider as a biologic marker of lower airway inflammation in nasal polyposis.

Impaired fasting glycaemia and undiagnosed diabetes: prevalence, cardiovascular and behavioural risk factors

BACKGROUND

Early discovery of type 2 DM (NIDDM) is essential. The diagnostic criteria of DM have been recently modified (FBG 126 vs 140 mg/dl) and the characteristics of undiagnosed subjects in large populations must be defined. At the same time subjects with impaired FBG need to be studied mainly for their cardiovascular complications.

METHODS

During 14 months, 61,724 male and female subjects (mean age 40) were explored in the French Institute for Health Protection (I.R.S.A). Clinical data, FPG, CV risk factors and dietary habits collected. Cut-off value for FPG: 110-125 mg/dl (IFG) (G2), 126-139 mg/dl defining undiagnosed diabetes with no history of diabetes. Subjects with FPG >=140 mg/dl (G4) former ADA/WHO criteria for diabetes and with the new criteria (FPG: 126-139 mg/dl) (G3) were compared to IFG (G2) and controls<110 mg/dl (G1).

RESULTS

With the new criteria (>=126 mg/dl) the prevalence of unknown diabetes in the cohort was 1.2% accounting for 41% of the overall prevalence of the disease (known + unknown). This is nearly 2.5 times more than with the previous criteria, > 140 mg/dl, (1.2 vs 0.5%). In G2/G1 and G3/G2 highest FPG had higher BMI, H/W ratio, heart rate (male only G3/G2), BP, gamma GT (role of alcohol in males), uric acid and TG. A role of absence of breakfast, low dairy products consumption is found. No difference between G4 and G3 found.

CONCLUSION

These results support the new criteria of FPG 126 mg/dl and suggest that it would be necessary to investigate and prevent cardiovascular risk factors as soon as fasting glycaemia is found to be over 110 mg/dl. Nutritional and behavioural education should be given at this early stage of the disease.

Strictureplasty in Crohn's disease: short- and long-term follow-up

Strictureplasty for obstructive Crohn's disease is still controversial because lesions are left in place and the suture is performed on a diseased bowel. Many surgeons prefer to perform bowel resection, hoping for fewer complications and a lower recurrence rate. In this paper, the authors reports their strictureplasty experience. They performed a systematic retrospective review of the patients suffering from Crohn's disease who underwent strictureplasties during a 10-year period in the abdominal surgery department of the University Hospital of Liège Sart Tilman, and studied the short- and long-term clinical results of 68 strictureplasties performed in 18 patients. Median follow-up was 63 months (range 12 to 144). Mortality was 0% and septic morbidity was 11% (one wound abscess and one leakage). Among the 16 patients available for the latest follow-up, symptomatic stenotic recurrence had to be medically treated in hospital for 4 patients (25%) with a recurrence delay range of 19 to 49 months. Stenosis recurrence needed re-intervention in one patient 48 months after surgery: stenosis occurred at a distance from the corrected site. These results confirmed that strictureplasty is a safe and efficient procedure in selected patients undergoing surgery for obstructive Crohn's disease.

Dy-complexes as high field T2 contrast agents: influence of water exchange rates

Dy complexes can act as suitable negative (T2) contrast agents for Magnetic Resonance Imaging (MRI). As clinical MRI moves toward higher fields, tuning of the exchange rate of coordinated water molecules will become necessary to optimize the r2 relaxivity. For Dy complexes, this will require lengthening of the water residence time, a strategy opposite that required to optimize the r1 relaxivity of Gd complexes. However, very slow water exchange can be deleterious. This is illustrated here by a Dy complex that is characterized by a very slow water exchange. This complex, Dy-DOTA-4AmCE, is compared with several Dy-DTPA derivatives known for their efficacy as T2 contrast agents at high magnetic fields.

Intrathoracic blood supply of the left vagus and recurrent laryngeal nerves

The arteries and veins of the left vagus (VN) and left recurrent laryngeal (RLN) nerves from the thoracic inlet to the subaortic region are described following vascular casting with red colored latex in 6 adult fresh non-embalmed cadavers. In all specimens the anterior bronchoesophageal artery supplied at least one vessel to the VN and RLN in the subaortic region. For the RLN other arterial sources were arteries arising from the aortic arch in 1 specimen, the subclavian artery in 3 specimens, the first intercostal artery in 1 specimen, and the inferior thyroid artery in all specimens. For the VN other arterial sources were arteries arising from the aortic arch in 2 specimens and the inferior thyroid artery in 1 specimen. For both the VN and RLN the veins were located under the pleura and directed towards the internal thoracic vein anteriorly and the thoracic intercostal veins posteriorly. In conclusion, the inferior thyroid artery at the thoracic inlet for the RLN and the anterior bronchoesophageal artery are the more consistent vessels supplying the VN and RLN. Vascular damage occurring during mediastinal lymph node excision to the VN and RLN, especially in the subaortic region, may explain postoperative vocal fold paralysis.

[The best of 2001. Arterial hypertension]

Last year, in 2001, the results of several major clinical trials have been published, concerning hypertensive patients with type 2 diabetes (IRMA, RENAAL and IDNT studies) and patients with previous strokes. Angiotensin II antagonists (irbesartan and losartan) are able to reduce the rate of progression of diabetic nephropathy in hypertensive patients with type 2 diabetes. This preventive effect occurs independently of the stage of renal dysfunction (early stage in IRMA, patent nephropathy in RENAAL and advanced nephropathy in IDNT). The PROGRESS study shows that the decrease in blood pressure, in response to an ACE inhibitor/diuretic bitherapy (perindopril/indapamide), in patients with previous minor stroke or transient ischaemic attack, reduces significantly the risk of recurrent stroke.

Folding of the rabbit hemorrhagic disease virus capsid protein and delineation of N-terminal domains dispensable for assembly

Rabbit hemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV) are caliciviruses that produce severe symptoms and are lethal to rabbits and hares. The folding of the capsid protein was studied by determination of the antigenic pattern of chimeric capsid proteins, composed of regions from RHDV and EBHSV capsid proteins. The anti-RHDV monoclonal antibody (MAb) E3, which is known to bind an external conformational epitope, recognized the RHDV C-terminal region. The anti-RHDV MAb A47, which binds a buried epitope, recognized the RHDV N-terminal region. Using a pGEX expression library, we more precisely mapped the MAb A47 epitope on a 31 residues length peptide, between residue 129 and 160 of the VP60, confirming its location in the N-terminal part of the protein. These results demonstrate that the C-terminal part of the protein is accessible to the exterior whereas the N-terminal domain of the protein constitutes the internal shell domain of the particle. With the aim of using virus-like particles (VLPs) of RHDV as epitope carriers or DNA transfer vectors, we produced in the baculovirus system three proteins, DeltaN1, DeltaN2 and DeltaN3, truncated at the N terminus. The DeltaN1 protein assembled into VLPs, demonstrating that the first 42 amino acid residues are not essential for capsid assembly. In contrast, DeltaN2, from which the first 75 residues were missing, was unable to form VLPs. The small particles obtained with the DeltaN3 protein lacking residues 31 to 93, located in the immunodominant region of the RHDV capsid protein, indicate that up to 62 amino acid residues can be eliminated without preventing assembly.

Local pulse pressure is a major determinant of large artery remodelling

1. The aim of the present brief review is to show that the pulsatile component of blood pressure is a stronger determinant of large artery remodelling than the steady component (i.e. mean blood pressure). 2. Pulse pressure, which is a strong determinant of cardiovascular events, including coronary heart disease and stroke, is increased when large arteries stiffen. Local pulse pressure, measured with applanation tonometry in normotensives and patients with essential hypertension, explains a significant part of the variance of intima-media thickness at the site of the carotid artery, a proximal elastic artery, whereas mean blood pressure does not contribute. Local pulse pressure has no influence on intima-media thickness at the site of the radial artery, a distal muscular artery that undergoes very little stroke change in diameter. 3. The decrease in carotid pulse pressure is also a major determinant of the regression of carotid intima-media thickness after antihypertensive treatment. Local pulse pressure can influence not only intima-media thickness, but also internal diameter. Indeed, there is a significant association between the lumen enlargement of the ascending aorta in patients with Marfan syndrome and pulse pressure. In addition, carotid pulse pressure is positively correlated with carotid internal diameter in normotensives and hypertensives, and the decrease in carotid internal diameter during long-term antihypertensive treatment is influenced by the decrease in carotid pulse pressure and not by the reduction in mean blood pressure. 4. We suggest that the effects of pulse pressure on large artery remodelling may explain part of its predictive value on cardiovascular events.

Clinical benefit of very-low-dose perindopril-indapamide combination in hypertension

OBJECTIVE

To review the efficacy and safety of the very-low-dose combination of 2 mg perindopril and 0.625 mg indapamide in essential hypertension.

STUDY SELECTION

The five main studies from the European registration file were performed in hypertensive outpatients and included two phase II double-blind randomised dose-ranging studies, and three phase III double-blind randomised studies (one study comparing placebo with each of the components, one long-term study over 15 months and one study comparing the combination and losartan).

MAIN OUTCOME MEASURES

Decreases in systolic (SBP) and diastolic (DBP) blood pressures measured at trough with a mercury sphygmomanometer, an automatic device (Omron), and 24 h ambulatory blood pressure measurements (ABPM).

RESULTS

The combination 2 mg perindopril and 0.625 mg indapamide was selected from the dose-finding studies. Twelve weeks after participants in the randomised studies were allocated to groups, the reductions in SBP, measured with an Omron device, were 12.3 +/- 15.0 mmHg with the combination, 8.0 +/- 16.5 mmHg with 2 mg perindopril (P = 0.001), 9.4 +/- 14.3 mmHg with 0.625 mg indapamide (P = 0.023), and 2.1 +/- 16.8 mmHg with placebo (P < 0.001) (mean +/- SD; all P values are for comparisons with the combination). The reductions in DBP were 6.8 +/- 9.2 mmHg, 5.0 +/- 9.5 mmHg (P = 0.02), 4.7 +/- 8.2 mmHg (P = 0.004), and 2.4 +/- 9.6 mmHg (P < 0.001) in the combination, 2 mg perindopril, 0.625 mg indapamide and placebo groups, respectively. During the long-term study, among 235 patients who achieved initial blood pressure normalisation with the fixed combination, 79.8% sustained their normalisation over 1 year, with no significant difference regarding safety criteria: the occurrence of adverse drug reactions per patient per year was 0.37 and 0.28 in the combination and placebo groups, respectively. A significantly (P < 0.05) larger blood pressure decreasing effect on nocturnal mean SBP (by ABPM) was demonstrated for the combination compared with that achieved with losartan, with no difference in safety.

CONCLUSIONS

The proven efficacy on DBP and SBP, and the good safety profile, confirm that the new low-dose combination of 2 mg perindopril and 0.625 mg indapamide is a valuable option in the first-line treatment of hypertension.

Compressibility of the carotid artery in patients with pseudoxanthoma elasticum

The arterial wall has generally been considered as noncompressible in in vitro studies. However, compressibility of the arterial wall (CAW) has never been studied in vivo in humans. Large interstitial proteoglycans play a major role in sustaining the compression generated by pulsatile forces. The aims of the present study were to develop an experimental methodology for the assessment of CAW in vivo in humans and to study CAW in patients with pseudoxanthoma elasticum (PXE), a genetic disease characterized by proteoglycan accumulation and fragmented, swollen, and calcified elastic fibers in connective tissues. We studied 19 female patients with PXE and 15 normal female control subjects matched for age and blood pressure. A high-resolution echo-tracking system was used for the continuous determination of internal diameter and wall thickness at the site of the common carotid artery. Matrices of the radiofrequency signal were analyzed with a dedicated software to measure carotid wall cross-sectional area every 4 milliseconds during 4 to 6 cardiac cycles. CAW was calculated as the stroke change in cross-sectional area. CAW was 44% higher in patients with PXE than in control subjects (6.8+/-2.6% versus 4.7+/-2.7%, respectively; P<0.05). In control subjects, CAW decreased with age in a linear manner (r=-0.75, P<0.01). In PXE patients, the relationship with age was not homogeneous: CAW tended to increase with age before 40 years (P=0.07) and significantly decreased with age in older patients (P<0.01). Carotid geometry and elastic properties did not differ between PXE patients and control subjects. In conclusion, CAW was measurable in vivo and noninvasively in humans. The higher CAW of PXE patients compared with that of control subjects suggests that proteoglycans are important determinants of compressibility.

Mechanical strength of the isolated carotid artery in SHR

We have previously reported an adaptation of arterial wall elasticity in spontaneously hypertensive rats (SHR) that involves an increase in both fibronectin/alpha5beta1-integrin complexes and smooth-muscle elastic lamellae connections. We examined the mechanical strength (MS) of the carotid artery in relation to its elastic properties, its elastin/collagen content, and the structure of the internal elastic lamina. MS was defined as the in vitro intraluminal pressure and wall stress that produces rupture of the vascular wall. Intact carotid arteries from 3-month-old normotensive rats (Wistar-Kyoto, WKY) and SHR were cannulated on a specially designed device and adjusted to their in situ length. A slowly increasing static pressure was applied until wall rupture occurred to determine the static mechanical behavior and MS. Static elasticity was similar in SHR and WKY, as were the rupture pressure (2740+/-90 versus 2740+/-40 mm Hg) and wall stress at rupture (11.5+/-1.0 versus 12.8+/-0.4 MPa), indicating equivalent MS in both groups. Histological examination showed several wall ruptures and dissociation of lamellar units that did not differ significantly between the 2 groups. Confocal microscopy showed that the size of fenestrations of the internal elastic lamina and the fraction of area occupied by them were reduced 3-fold in SHR. We have demonstrated that static elasticity of the arterial wall and mechanical strength are similar in carotid arteries from SHR and WKY.

Vocal cord dysfunction after left lung resection for cancer

OBJECTIVES

To evaluate the prevalence, the impact-related postoperative complications and the risk factors of vocal cord dysfunction (VCD) after left lung resection for cancer.

METHODS

From February 1996 to April 1999, a review of prospectively gathered data was performed on 99 consecutive patients who underwent a pneumonectomy (n=50) or a lobectomy (n=49) with a mediastinal lymph node dissection. A fiber optic laryngeal examination was performed preoperatively for all patients and within the first week postoperatively in patients with symptom(s) or sign(s) of VCD or respiratory complications.

RESULTS

Thirty-one patients (31%) had a postoperative VCD (group VCD) and 68 (68%) did not (group non-VCD). Mortality rate was 19% in group VCD and 9% in group non-VCD (P=0.13). Group VCD patients developed more pulmonary complications (P=0.014) and cardiac complications (P<0.001) compared to group non-VCD patients. A higher rate of reintubation (P=0.005), pneumonia (P=0.06), arrhythmia (P=0.002), cardiac failure (P<0.001) was noticeable in group VCD and may account for the higher rate of complications in this group. Using multivariate analysis, preoperative radiotherapy (P=0.001) and pneumonectomy (P=0.008) were predictive of postoperative VCD. Hospital stay was 22+/-16 days in group VCD and 13+/-9 days in group non-VCD (P<0.002).

CONCLUSION

VCD is a frequent event that can lead to dramatic pulmonary complications. We would recommend to track it and to treat it as early as possible.

Expression of presumed specific early and late factors associated with liver regeneration in different rat surgical models

Experiments performed on the portal branch ligation (PBL) model indicate that early changes observed after surgery are not related to the regenerative process because they also occur in atrophying lobes. To further confirm the lack of specificity of the early events and to exclude the influence of circulatory factors released by proliferating lobes on their occurrence, we investigated this response after sham operation (SO) and portacaval shunt (PCS), a model characterized by liver atrophy. We also attempted to determine expression of later events associated specifically with regeneration, ie, expression of p53 or c-Ha-ras, or inhibition of proliferation, ie, interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) after partial (PH) and temporary partial (TPH) hepatectomy, SO and PCS. Nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription 3 (STAT3) DNA binding were assessed by electrophoretic mobility shift assay (EMSA), interleukin-6 (IL-6) mRNA by reverse transcription-polymerase chain reaction (RT-PCR), c-myc and c-jun mRNAs by Northern blot analysis at 0.5 and 2 hours, p53 and c-Ha-ras mRNAs by Northern blot analysis at 8 and 24 hours, and IL-1beta and TGF-beta1 by RT-PCR at 24 hours. The early response including an increase of NF-kappaB, STAT3, IL-6, and immediate-early genes expression was present after PH, PCS, and SO. In SO, slight differences were observed in comparison with PH: no NF-kappaB p65/p50 DNA binding was observed, only three of six SO rats were positive for IL-6, and immediate-early genes induction showed differences in the intensity of the response. At later times, p53 mRNA increased at 8 hours after PH and TPH, c-Ha-ras mRNA at 24 hours after PH, and IL-1beta mRNA at 24 hours after PCS. Early events are not specifically associated with the reduction of liver mass or with the regenerative process, are not predictive of future cell fate, and are most likely related to surgical stress. p53 and c-Ha-ras induction is closely associated with cell cycle progression whereas IL-1beta, but not TGF-beta1, appears to be one of the negative growth regulators that might play an important role in atrophy.

Rab3a controls exocytosis in cholecystokinin-secreting cells

The expression of rab3A and rab3D isoforms in the enteroendocrine, cholecystokinin-secreting, cell lines STC-1 and GLUTag is here demonstrated. In contrast, rab3B is undetectable in these two cell lines, and rab3C is only slightly expressed in GLUTag cells. Using a transient co-transfection system with human growth hormone as reporter protein, we show that overexpression of the GTPase-deficient mutant rab3AQ81L, but not rab3DQ81L, significantly decreases human growth hormone secretory responses to various agonists in STC-1 cells. These results indicate that endocrine cell lines of intestinal origin express rab3A and rab3D proteins, but the GTP-bound form of rab3A only acts as a negative modulator in the control of cholecystokinin secretion from STC-1 cells.

[Effect of acupuncture on radial artery hemodynamics. Two controlled studies in pre-exposed and naive healthy subjects]

Palpation of the radial pulses is one of the most important techniques in traditional Chinese medicine. Two double-blind randomised trials of the effects of real and sham acupuncture on radial artery hemodynamics were conducted in 19 patients regularly exposed to acupuncture (sensitised subjects), and in 8 healthy subjects devoid of previous exposure (naive subjects), respectively. Radial artery diameter and pulse waveform was measured with a high-resolution echotracking system and aplanation tonometry, respectively, before and during a 20-minute's acupuncture period. In sensitised patients, arterial diameter significantly increased during real acupuncture, compared to the sham group (+7.5 +/- 2.8% vs -2.9 +/- 2.7%, respectively; p < 0.01). By contrast, in naive subjects, arterial diameter did not change during real or sham acupuncture. In both populations, no significant difference was observed between real and sham acupuncture, concerning the time-course of blood pressure, radial artery distensibility and pressure waveform. Our results demonstrate that real acupuncture can determine an objective vasodilatation of the radial artery in patients regularly exposed to acupuncture, but not in naive subjects.

[Reversible hypokinetic cardiomyopathy revealing severe hypocalcemia]

Dilated cardiomyopathy may be primary or secondary. Although some causes are well known, such as toxic substances (alcohol, chemotherapy...) or viral infections, biochemical abnormalities are much less common. The authors report the case of a 58 year old woman with no previous history admitted to hospital for an inaugural episode of cardiac failure. The ECG showed sinus tachycardia with a long QT interval (560 mm) and a dilated hypokinetic cardiomyopathy with a left ventricular ejection fraction of 20%. The aetiological investigation showed severe hypocalcaemia (0.66 mmol/L) related to primary hypoparathyroidism. This is an important cause to remember because its treatment leads to correction of the cardiac disease, usually within weeks.

Mechanical properties and structure of carotid arteries in mice lacking desmin

OBJECTIVE

Our aim was to determine in desmin homozygous mutant mice the viscoelastic properties, the mechanical strength and the structure of the carotid artery.

METHODS

To assess the viscoelastic properties of large arteries, we have performed an in vivo analysis of the diameter-, and distensibility-pressure curves of the common carotid artery (CCA) in homozygous (Des -/-), heterozygous (Des +/-) and wild-type (Des +/+) mice. To evaluate the mechanical strength, we have measured the in vitro intraluminal pressure producing the rupture of the carotid artery wall. The structure analysis of the arterial wall was based on histology and electronic microscopy.

RESULTS

A lower distensibility and an increase of arterial wall viscosity were observed in Des -/- compared with Des +/+. Arterial thickness of Des -/- was similar to those of Des +/+, without changes in elastin and collagen contents. Electron microscopy revealed that the perimeter of cellular fingerlike-projections was smaller in Des -/-, indicating that the cells have lost part of their connections to the extracellular matrix. The rupture pressure was significantly lower in Des -/- (1500+/-200 mmHg) compared with Des +/+ (2100+/-80 mmHg) indicating a lower mechanical strength of the vascular wall. No significant difference was found between Des +/- and Des +/+.

CONCLUSION

The desmin is essential to maintain proper viscoelastic properties, structure and mechanical strength of the vascular wall.

Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients

Although various studies reported that pulse pressure, an indirect index of arterial stiffening, was an independent risk factor for mortality, a direct relationship between arterial stiffness and all-cause and cardiovascular mortality remained to be established in patients with essential hypertension. A cohort of 1980 essential hypertensive patients who attended the outpatient hypertension clinic of Broussais Hospital between 1980 and 1996 and who had a measurement of arterial stiffness was studied. At entry, aortic stiffness was assessed from the measurement of carotid-femoral pulse-wave velocity (PWV). A logistic regression model was used to estimate the relative risk of all-cause and cardiovascular deaths. Selection of classic risk factors for adjustment of PWV was based on their influence on mortality in this cohort in univariate analysis. Mean age at entry was 50+/-13 years (mean+/-SD). During an average follow-up of 112+/-53 months, 107 fatal events occurred. Among them, 46 were of cardiovascular origin. PWV was significantly associated with all-cause and cardiovascular mortality in a univariate model of logistic regression analysis (odds ratio for 5 m/s PWV was 2.14 [95% confidence interval, 1.71 to 2.67, P<0.0001] and 2.35 [95% confidence interval, 1.76 to 3.14, P<0.0001], respectively). In multivariate models of logistic regression analysis, PWV was significantly associated with all-cause and cardiovascular mortality, independent of previous cardiovascular diseases, age, and diabetes. By contrast, pulse pressure was not significantly and independently associated to mortality. This study provides the first direct evidence that aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in patients with essential hypertension.

Albumin-bound MRI contrast agents: the dilemma of the rotational correlation time

Human serum albumin (HSA) binds numerous molecules, among which are suitably designed MRI contrast agents. The rotational tumbling of the protein is thus one of the parameters likely to affect the in vivo relaxivity of these agents. Literature unveils discrepancies about the value of the rotational correlation time (tau(R)) of HSA. In the present work, the tau(R) of this protein has been determined by studying the deuterium relaxation rate of small molecules known for their strong binding to HSA (warfarin and 4-hydroxycoumarin). Values of approx. 20-22 ns are obtained at 310 K in a 4% HSA solution and are in good agreement with the theoretical predictions.

Deuterium NMR study of the MP-2269: albumin interaction--a step forward to the dynamics of non-covalent binding

MP-2269, the Gd(III) complex of 4-pentylbicyclo[2.2.2]octane-1-carboxyl-di-L-aspartyl-lysine-derived-DTPA, is a small Gd-agent that binds non-covalently to serum albumin in vivo to assume the enhanced relaxivities associated with macromolecular agents, (due in part to increased rotational correlation time, tau(R)). To further explore the fundamental parameters that govern the dynamics of water proton relaxation enhancement by this prototypical albumin-binding agent, the rotational correlation time (tau(R)) for the deuterated La(III) analog of MP-2269 has been independently measured in the presence and absence of 4% albumin using 2H-NMR approaches. The diamagnetic La(III) analog of MP-2269 was deuterated at the alpha-position of the carbonyl groups. 2H-NMR studies were conducted at 7.05T (46 MHz) and 310 degrees K on a Bruker NMR spectrometer. Spectral deconvolution permitted calculation of transverse relaxation rates, 1/T(2), from the NMR linewidths and subsequently, tau(R). The results yielded a tau(R) of the albumin bound complex of approximately 8 ns. This value is intermediate between those earlier estimated by 17O-NMR ( approximately 1 ns) and 1H-NMRD ( approximately 20-50 ns) and significantly shorter than that of albumin. The 2H-NMR study results also indicate that the exchange between free and albumin-bound forms of the La(III) analog is slow (exchange lifetimes >1 ms). This slow exchange does not affect the water residence lifetimes (tau(M) 140-280 ns).

Community assessment in a vertically integrated health care system

OBJECTIVES

In this report, the authors present a representative case of the implementation of community assessment and the subsequent application of findings by a large, vertically integrated health care system.

METHODS

Geographic information systems technology was used to access and analyze secondary data for a geographically defined community. Primary data included a community survey and asset maps.

RESULTS

In this case presentation, information has been collected on demographics, prevalent health problems, access to health care, citizens' perceptions, and community assets. The assessment has been used to plan services for a new health center and to engage community members in health promotion interventions.

CONCLUSIONS

Geographically focused assessments help target specific community needs and promote community participation. This project provides a practical application for integrating aspects of medicine and public health.

Fenestrations of the carotid internal elastic lamina and structural adaptation in stroke-prone spontaneously hypertensive rats

Our aim was to determine the structural factors that determine the mechanical adaptation of the carotid arterial wall in stroke-prone hypertensive rats (SHRSP). Distensibility-pressure and elastic modulus-stress curves assessed by in vivo echo-tracking measurements indicated a reduction in arterial stiffness in 13-week-old SHRSP compared with Wistar-Kyoto rats (WKY). Elastin and collagen contents determined biochemically were not different between SHRSP and WKY. Confocal microscopy showed that the mean area of fenestrations and fraction of area occupied by fenestrations of the internal elastic lamina (IEL) were smaller in SHRSP than in WKY, which indicated a reduction in stress-concentration effects within the IEL. Immunohistologic staining of EIIIA fibronectin isoform and total fibronectin (also as determined by Western blot) was greater in SHRSP, which suggested increased cell-matrix interactions. We suggest that these structural modifications of the vascular wall play a synergistic role in the mechanical adaptation to a high level of stress in SHRSP.

Slow clearance gadolinium-based extracellular and intravascular contrast media for three-dimensional MR angiography

The objective of this study was to assess two new slow-clearance contrast media with extracellular and intravascular distribution for magnetic resonance angiography (MRA). Extracellular Gd-DTPA-BC(2)glucA and intravascular Gd(DO3A)(3)-lys(16) were developed within the European Biomed2 MACE Program and compared with two reference compounds, intravascular CMD-A2-Gd-DOTA and extracellular GdDOTA, in 12 rats. Pre- and post-contrast three-dimensional MR (TR/TE = 5 msec/2.2 msec; isotropic voxel size 0.86 mm(3)) was acquired for 2 hours. Signal-to-noise enhancement (DeltaSNR) was calculated. Two minutes after injection, all contrast media provided strong vascular signal enhancement. The DeltaSNR for Gd-DTPA-BC(2)glucA, Gd(DO3A)(3)-lys(16), CMD-A2-Gd-DOTA, and GdDOTA were 13.0 +/- 1.8, 25.0 +/- 3.2, 25.0 +/- 4.0, and 18.0 +/- 3.4, respectively. Gd-DTPA-BC(2)glucA, Gd(DO3A)(3)-lys(16), and CMD-A2-Gd-DOTA cleared slowly from the circulation, whereas GdDOTA cleared rapidly. Vascular DeltaSNR at 2 hours were 2.9 +/- 0.6, 25.0 +/- 3.2, 25.0 +/- 4.0, and 0.4 +/- 1.0. Gd(DO3A)(3)-lys(16) provided strong vascular and minor background enhancement, and thus may be useful for MRA or perfusion imaging. Gd-DTPA-BC(2)glucA produces persistent enhancement of extracellular water, and thus may allow quantification of extracellular distribution volume and assessment of myocardial viability.

Stereospecific binding of MRI contrast agents to human serum albumin: the case of Gd-(S)-EOB-DTPA (Eovist) and its (R) isomer

The water proton relaxation rate enhancement of the hepatospecific Gd-(S)-EOB-DTPA (Eovist) and of its (R) isomer in aqueous solutions free of protein, in serum and in 4% human serum albumin solution, are compared. In the absence of proteins, both compounds exhibit, as expected, the same proton relaxivity, as measured by the nuclear magnetic relaxation dispersion (NMRD) profiles. In serum and albumin solution, non-covalent binding of the paramagnetic complexes to macromolecules is observed. Both isomers are likely to bind to the same site of human serum albumin, but the affinity of the (S) isomer is larger than for the (R) isomer.

Effects of acupuncture on radial artery hemodynamics: controlled trials in sensitized and naive subjects

Palpation of the radial pulses is an important technique in traditional Chinese medicine. Two double-blind randomized trials of the effects of real and sham acupuncture on radial artery hemodynamics were conducted in 19 patients regularly exposed to acupuncture (sensitized subjects) and in 8 healthy subjects devoid of previous exposure (naive subjects), respectively. Radial artery diameter and pulse waveform were measured with a high-resolution echotracking system and aplanation tonometry, respectively, before and during a 20-min acupuncture period. In sensitized patients, arterial diameter significantly increased during real acupuncture, compared with the sham group (+7.5 +/- 2.8 vs. -2.9 +/- 2.7%, respectively; P < 0.01). By contrast, in naive subjects, arterial diameter did not change during real or sham acupuncture. In both populations, no significant difference was observed between real and sham acupuncture, concerning the time course of blood pressure, radial artery distensibility, and pressure waveform. Our results demonstrate that real acupuncture is associated with an objective vasodilatation of the radial artery in patients regularly exposed to acupuncture, but not in naive subjects.

Stability of MRI paramagnetic contrast media: a proton relaxometric protocol for transmetallation assessment

RATIONALE AND OBJECTIVES

The suitability of paramagnetic complexes as magnetic resonance contrast agents depends on various factors such as their relaxivity, stability, selectivity, and the inertness toward transmetallation by endogenous ions. The transmetallation of a series of 18 gadolinium complexes by the Zn2+ ion was studied in vitro by proton relaxometry.

METHODS

Transmetallation was analyzed through the evolution of the paramagnetic longitudinal relaxation rate of water protons at 37 degrees C in pH = 7 phosphate buffer solutions containing 2.5 mmol/L of the gadolinium complexes and 2.5 mmol/L zinc chloride. The measurements were performed at 0.47 T over a period of at least 3 days.

RESULTS

The results confirm the high stability of macrocyclic systems and a high sensitivity of Gd-diethylenetriamine-pentaacetic acid (DTPA) derivatives to transmetallation by Zn2+ ions. The decreasing order of stability with respect to metal exchange is as follows: Gd-macrocyclics > Gd-C-functionalized DTPA > Gd-DTPA > primary and secondary Gd-DTPA bisamides. The ternary bisamide analyzed in this study [Gd-DTPA-1,11-bisbismethylamino-1,11-dioxo-3,6,9-triaza-3,6,9-tris(carboxymethyl)undecane] is more stable than the parent compound Gd-DTPA.

CONCLUSIONS

A simple relaxometric protocol has been successfully developed to study the in vitro transmetallation process of gadolinium complexes. The importance of the functionalization and substitution of the DTPA-like complexes is clearly shown.

Detection of avian oncogenic Marek's disease herpesvirus DNA in human sera

The avian herpesvirus Marek's disease virus (MDV) has a worldwide distribution and is responsible for T-lymphoma in chickens. The question as to whether MDV poses a public health hazard to humans was first raised when the virus was isolated in 1967. However, no irrefutable results have been obtained in immunological and virological studies. We used a nested-PCR to detect MDV DNA in human serum samples. A total of 202 serum samples from individuals exposed and not exposed to poultry was tested by nested-PCR for a target sequence located in the MDV gD gene. The assay system was specific and sensitive, making it possible to detect a single copy of the target sequence. Forty-one (20%) of the 202 serum samples tested positive for MDV DNA. The prevalence of MDV DNA was not significantly different in the group exposed to poultry and the group not exposed to poultry. There was also no difference due to age or sex. Alignment of the 41 gD sequences amplified from human sera with eight gD sequences amplified from MDV-infected chicken sera showed a maximum nucleotide divergence of 1.65%. However, four 'hot-spot' mutation sites were identified, defining four groups. Interestingly, two groups contained only human MDV-gD sequences. The status of the MDV genome detected in human blood is discussed.

Gene transfer using recombinant rabbit hemorrhagic disease virus capsids with genetically modified DNA encapsidation capacity by addition of packaging sequences from the L1 or L2 protein of human papillomavirus type 16

The aim of this study was to produce gene transfer vectors consisting of plasmid DNA packaged into virus-like particles (VLPs) with different cell tropisms. For this purpose, we have fused the N-terminally truncated VP60 capsid protein of the rabbit hemorrhagic disease virus (RHDV) with sequences which are expected to be sufficient to confer DNA packaging and gene transfer properties to the chimeric VLPs. Each of the two putative DNA-binding sequences of major L1 and minor L2 capsid proteins of human papillomavirus type 16 (HPV-16) were fused at the N terminus of the truncated VP60 protein. The two recombinant chimeric proteins expressed in insect cells self-assembled into VLPs similar in size and appearance to authentic RHDV virions. The chimeric proteins had acquired the ability to bind DNA. The two chimeric VLPs were therefore able to package plasmid DNA. However, only the chimeric VLPs containing the DNA packaging signal of the L1 protein were able efficiently to transfer genes into Cos-7 cells at a rate similar to that observed with papillomavirus L1 VLPs. It was possible to transfect only a very limited number of RK13 rabbit cells with the chimeric RHDV capsids containing the L2-binding sequence. The chimeric RHDV capsids containing the L1-binding sequence transfer genes into rabbit and hare cells at a higher rate than do HPV-16 L1 VLPs. However, no gene transfer was observed in human cell lines. The findings of this study demonstrate that the insertion of a DNA packaging sequence into a VLP which is not able to encapsidate DNA transforms this capsid into an artificial virus that could be used as a gene transfer vector. This possibility opens the way to designing new vectors with different cell tropisms by inserting such DNA packaging sequences into the major capsid proteins of other viruses.

Early down-regulation of cytochrome P450 3A and 2E1 in the regenerating rat liver is not related to the loss of liver mass or the process of cellular proliferation

AIMS/BACKGROUND

Conflicting data have been reported concerning the modification of cytochrome P450 expression in the regenerating liver. Ligation of branches of the portal vein (PBL) perfusing 70% of the liver parenchyma, which produces regeneration and atrophy within the same liver, constitutes an ideal model to study the relative specificity of the early events in the regenerating liver and their relationship to the loss of liver mass.

METHODS

In this PBL model and in sham models, we studied the expression and the metabolic activities of two major cytochromes, CYP3A and CYP2E1, and the expression of inducible nitric oxide synthase protein (iNOS). They were simultaneously measured in the atrophying and regenerating liver lobes following PBL using Western Blot and HPLC methods.

RESULTS

The metabolic activities of both cytochromes were transiently and simultaneously down-regulated in the regenerating and atrophying lobes during the first 2-5 h after PBL. No significant modification was observed at the protein level. In contrast, iNOS protein was significantly induced in both lobes. Similar results were observed after sham operation.

CONCLUSIONS

The reduction of these CYP activities in both lobes after PBL and in sham livers suggests that other mechanisms than the regenerating process itself or the reduction of the liver mass might account for such down-regulation during the early phase of liver regeneration. The activation of nitric oxide (NO) and/or pro-inflammatory cytokine production provides clues to pathways liable to affect the CYP activities in the regenerating liver.

[Local pulse pressure and regression of arterial wall hypertrophy during antihypertensive treatment. CELIMENE study. The Celiprolol Intima-Media Enalapril Efficacy study]

BACKGROUND

Local Pulse Pressure (PP) is an independent determinant of carotid artery wall thickness, stronger than mean BP. The present study was designed to assess whether a beta-adrenoceptor antagonist or an ACE inhibitor-based treatment was able to reduce carotid artery wall hypertrophy through the reduction in carotid PP rather than by lowering mean BP, and whether the influence of local PP reduction could also be detected at the site of a muscular artery, the radial artery.

METHODS AND RESULTS

Ninety-eight essential hypertensive patients were randomised to 9 months of double-blind treatment with either celiprolol or enalapril. Arterial parameters were determined with high resolution echotracking systems. PP was measured locally with PP applanation tonometry, and independently of mean BP. After 9 month's treatment, mean BP, carotid PP and intima-media thickness (IMT) decreased significantly, with no difference between the tow groups. The reduction in carotid pression pulsée, but not in mean BP, was a major independent determinant of the reduction in carotid IMT. Radial artery IMT and PP decreased significantly with both treatments. However, the reduction in radial artery IMT was not related to the changes in radial artery PP.

CONCLUSION

The regression of carotid artery wall hypertrophy during long-term antihypertensive treatment was dependent on the reduction in local PP rather than on the lowering of mean BP. The effect of PP lowering on IMT reduction was observed at the site of an elastic artery but not at the site of a muscular artery.

[Assessment of the management of arterial hypertension in a population of (type 2) diabetic patients undergoing hospitalization. Diabetes and prognostic factors in the control of arterial hypertension]

The control of hypertension in diabetic hypertensive patients prevents micro and macroangiopathy complications. Our prospective study was designed to evaluate the level of treatment of hypertension in type II diabetic patients at the time of referral to our endocrinology unit and after a mean follow-up of 9.2 months. Five hundred and sixty four patients (sex ratio: 1.15, mean age of 56 +/- 13, mean BMI of 28 +/- 15, mean duration of diabetes of 11.3 +/- 9.9) were referred to our unit. Among these, 42% had an antihypertensive drug (58% under monotherapy, 42% under combinations) and 92% had a documented history of CHD. Glycemic and blood pressure controls were stable during follow-up. HbA1c remained unchanged (8.95% at admission, 8.8% at 9 months) BP decreased from 143/84 +/- 26/13 mmHg to 142/82 +/- 23/13 mmHg. Fifty six percent reached a BP goal of 140/90 mmHg whereas 42% achieved a BP goal of 130/85 mmHg at 9 months compared to respectively 56% and 39% at admission. A multivariate logistic regression analysis showed that initial value of SBP (p < 0.0001), age (p < 0.0001), BMI (p = 0.006), HbA1c (p = 0.018) were independent factors of non control of hypertension. In conclusion, follow-up of hypertension diabetic patients would be focussed on identified and modifiable factors.

Local pulse pressure and regression of arterial wall hypertrophy during long-term antihypertensive treatment

BACKGROUND

Local pulse pressure (PP) is an independent determinant of carotid artery wall thickness, stronger than mean blood pressure (BP). The present study was designed to assess whether a beta-adrenoceptor antagonist-based or an ACE inhibitor-based treatment was able to reduce carotid artery wall hypertrophy through a reduction in carotid PP rather than by lowering mean BP and whether the influence of local PP reduction could also be detected at the site of a muscular artery, the radial artery.

METHODS AND RESULTS

Ninety-eight essential hypertensive patients were randomized to 9 months of double-blind treatment with either celiprolol or enalapril. Arterial parameters were determined with high-resolution echo-tracking systems. PP was measured locally with applanation tonometry and independently of mean BP. After 9 months of treatment, mean BP, carotid PP, and intimal-medial thickness (IMT) decreased significantly, with no difference between the 2 groups. The reduction in carotid PP but not in mean BP was a major independent determinant of the reduction in carotid IMT. Radial artery IMT and PP decreased significantly with both treatments. However, the reduction in radial artery IMT was not related to the changes in radial artery PP.

CONCLUSIONS

The regression of carotid artery wall hypertrophy during long-term antihypertensive treatment was dependent on the reduction in local PP rather than on the lowering of mean BP. The effect of PP lowering on IMT reduction was observed at the site of an elastic artery but not at the site of a muscular artery.

Intrinsic stiffness of the carotid arterial wall material in essential hypertensives

We have previously shown that the decrease in large artery distensibility observed in patients with essential hypertension (HT group) was primarily due to an increase in distending pressure and not to hypertension-associated structural modifications of the artery, suggesting a functional adaptation of the wall material. To evaluate the elastic properties of the wall material of the common carotid artery, we determined Young's incremental elastic modulus (Einc) in the HT group and in normotensive subjects (NT group) as a function of blood pressure and circumferential wall stress. In 102 HT patients with never-treated essential hypertension and 40 age- and gender-matched NT subjects, the Einc-pressure and Einc-stress curves were calculated from intima-media thickness and from diameter and pressure waveforms, determined with echo tracking and aplanation tonometry, respectively. The "effective" stiffness of the wall material, determined through Einc calculated at mean blood pressure, was significantly higher in the HT than in the NT group. The "intrinsic" stiffness of the wall material, determined through Einc calculated at a common circumferential wall stress, did not differ between the 2 groups. However, when each group (HT and NT) was analyzed according to tertiles of age, the "intrinsic" stiffness of the arterial wall material was increased only in younger HT patients. In middle-aged and older HT patients, the intrinsic mechanical properties of the carotid arterial wall material were unchanged, and the increased stiffness of the common carotid artery in the HT group was due primarily to the increased level of blood pressure. These results also indicate that the deleterious effects of aging and hypertension on "intrinsic" stiffness are not additive.

Antihypertensive effects of fasidotril, a dual inhibitor of neprilysin and angiotensin-converting enzyme, in rats and humans

The aim of this study was to assess the antihypertensive activity of fasidotril, a dual inhibitor of neprilysin (NEP) and angiotensin I-converting enzyme (ACE), in various models of hypertension in rats (spontaneously hypertensive rats [SHR]; renovascular Goldblatt 2-kidney, 1-clip rats; and deoxycorticosterone acetate [DOCA]-salt hypertensive rats) and in patients with mild-to-moderate essential hypertension. Fasidotril treatment (100 mg/kg PO twice daily for 3 weeks) resulted in a progressive and sustained decrease in systolic blood pressure (-20 to -30 mm Hg) in SHR and Goldblatt rats compared with vehicle-treated rats and prevented the progressive rise in blood pressure in DOCA-salt hypertensive rats. After a 4-week placebo run-in period, 57 patients with essential hypertension were included in a randomized double-blind, placebo-controlled, parallel-group study and received orally either fasidotril (100 mg twice daily) or placebo for 6 weeks. Blood pressure was measured during the 6 hours after the first intake and then at trough (12 hours after the last intake) on days 7, 28, and 42. The first dose of fasidotril had no significant effect on blood pressure. After 42 days, compared with placebo, fasidotril lowered supine systolic and diastolic blood pressures by 7.4/5.4 mm Hg and standing blood pressure by 7.6/6.8 mm Hg. Fasidotril, a dual NEP/ACE inhibitor, was an effective oral antihypertensive agent during chronic treatment in high-renin renovascular rats, normal-renin SHR, and low-renin DOCA-salt hypertensive rats and in patients with essential hypertension.

Association between the apolipoprotein E polymorphism and arterial wall thickness in asymptomatic adults

OBJECTIVES

The polymorphism of the apolipoprotein E gene (epsilon2, epsilon3, epsilon4) affects plasma cholesterol but the relationship with artery wall thickness has indicated contradictory results. This study investigated the relationship between apolipoprotein E polymorphism and vascular phenotypes of the carotid and radial arteries, two arterial sites differently affected by atherosclerosis.

METHODS

We studied a cohort of 320 Caucasian subjects (age 49 +/- 12 years) without evidence of cardiovascular disease. Structural (internal diameter and wall thickness) and functional phenotypes (compliance, distensibility) were evaluated for the common carotid and the radial arteries using high resolution echo-tracking devices. Genotypes of apolipoprotein E were determined by allele-specific oligonucleotides hybridization. Because of the relative low frequency of some apolipoprotein E genotypes, they were designated as E2 (epsilon2/epsilon2, epsilon2/epsilon3), E3 (epsilon3/epsilon3), and E4 (epsilon4/epsilon4, epsilon3/epsilon4).

RESULTS

Apolipoprotein E allele frequencies were epsilon2 = 0.08, epsilon3 = 0.79, epsilon4 = 0.13. Subjects with epsilon4 allele had the highest levels of total serum cholesterol and low density lipoprotein cholesterol; subjects with epsilon2 allele had the lowest levels (P < 0.001). Considering carotid hypertrophy as intima-media thickness > 660 microm, and radial hypertrophy as intima-media thickness > 260 microm, a logistic regression model testing determinants of arterial hypertrophy (age, gender, weight, systolic blood pressure, smoking habits, and total serum cholesterol) observed a significant and positive association between carotid hypertrophy and epsilon2 allele carriers (P= 0.03). In contrast, no association was found between hypertrophy and apolipoprotein E genotypes for the radial artery. No association was observed between the apolipoprotein E genotypes and functional artery parameters.

CONCLUSIONS

In subjects without any evidence of cardiovascular disease, the presence of the epsilon2 allele is related to wall hypertrophy in carotid artery despite favourable effect on the lipid profile.

[Auditing of drug use practices in anesthesia]

OBJECTIVES

Internal pharmaceutical practice guidelines were produced in a department of anaesthesia of a University hospital in 1995, after a preliminary evaluation showing controversial and expensive practices. After approval, these recommendations were circulated to all members of the department. Phase I of this study was started 18 months later, to evaluate the compliance of anaesthetists with these guidelines.

STUDY DESIGN

Prospective survey.

METHOD

An audit was performed by a research assistant pharmacist, previously trained, who compared anaesthetic agents and fresh gas flows used during anaesthetics with those recommended in the internal guidelines.

RESULTS

Implementation of guidelines was observed in more than 90% of cases for all agents studied, except for non-depolarizing neuromuscular relaxants. Relaxants of intermediate duration were used in 52% of cases with an expected surgery duration of more than 90 min, in opposition to the guidelines stating that pancuronium should have been administered in such circumstances. These results were presented and discussed. Slight changes in the guidelines (especially concerning monitoring of neuromuscular blockade) were made and evaluated again, using the same method (Phase II). A small but significant improvement was seen with induction agents (use of propofol in non-approved situations: 5 versus 0%, P = 0.03), while a non significant trend toward better implementation of guidelines was seen with non-depolarizing agents (use of pancuronium in surgery of expected duration > 90 min: phase I vs phase II = 47 vs 52%, NS; use of pancuronium in surgery of expected duration < 90 min: phase I vs phase II = 3.5 vs 0%, NS).

CONCLUSION

This study suggests that implementation of internal guidelines is easy when clinical indications of the agents are not controversial.

[Treatment of border-line dilatation of the ascending aorta using the Robicsek intervention]

The technique and the results of the external contention of the dilated ascending aorta by the application of an external Dacron graft are reported. This technique, without replacing the usual graft interposition, can efficiently and expeditiously treat borderline dilatation of the ascending aorta, as frequently encountered in aortic valve disease. If the sinotubular junction is not dilated, this technique may stop the aneurysmal evolution of the ascending aorta.

Association between local pulse pressure, mean blood pressure, and large-artery remodeling

BACKGROUND

The aim of the present study was to determine the respective influences of local pulse pressure and mean blood pressure on arterial remodeling in humans at 2 arterial sites: a central, predominantly elastic artery (the common carotid artery) and a peripheral muscular artery (the radial artery).

METHODS AND RESULTS

Forty-three healthy subjects and 124 never-treated hypertensive patients were included in the study. Intima-media thickness and internal diameter of the carotid and radial arteries were noninvasively determined with high-definition echo-tracking devices. Pulse pressure was measured locally with applanation tonometry. Multivariate regression models including mean blood pressure and local pulse pressure were established in the whole population. Carotid internal diameter and intima-media thickness were strongly influenced (P<0.0001) by carotid pulse pressure but not by mean blood pressure or brachial pulse pressure, independently of age and sex. Radial artery internal diameter was correlated with age but not with mean blood pressure or radial pulse pressure. Radial artery intima-media thickness was correlated with mean blood pressure (P<0.001) but not with radial pulse pressure.

CONCLUSIONS

Carotid pulse pressure was a strong independent determinant of carotid artery enlargement and wall thickening, whereas mean blood pressure and brachial pulse pressure were not, indicating the prominent influence of local pulsatile mechanical load on arterial remodeling. These relationships were observed at the site of an elastic artery but not at the site of a muscular artery, suggesting the contribution of cyclic stretching to the pulse pressure-induced arterial remodeling.

[Molecular and cellular determinants of arterial stiffness: role of cell-matrix connections]

Increased large artery stiffness is believed to be a cardiovascular risk factor independent from mean arterial pressure. The mechanical properties of large arteries depend not only on the amounts of their main constituents (elastin, collagen, and smooth muscle cells) but also on the spatial organization and mechanical interactions among these components. These interactions may be mediated by extracellular matrix adhesion proteins and their membrane receptors or integrins. From a mechanical viewpoint, a key element may be the dense plaque, which is composed of cytoskeletal proteins linked to matrix proteins via membrane integrin receptors. Integrin expression in normal and diseased blood vessels is currently the focus of active research. In humans, hypertension-related arterial hypertrophy is not associated with an increase in intrinsic arterial wall stiffness. Aortic fibronectin expression is increased in spontaneously hypertensive rats (SHRs). By increasing cell-matrix anchoring, fibronectin may contribute to protect arterial wall components from the increased mechanical loads associated with hypertension. In atherosclerosis, the increase in cell-matrix anchoring plays a key role in preventing atheroma plaque rupture. To determine the exact role of adhesion molecules in arterial stiffness, there is a need for studies involving use of specific anti-integrin agents and of transgenic animal models.

[Hypertrophy of the arterial wall and arterial rigidity]

The purpose of this article is to review the relations between hypertension-induced hypertrophy and stiffness of the arterial wall. Arterial remodeling was assessed based on the geometrical (lumen and arterial wall thickness) and functional (distensibility and Young's elastic modulus) properties of large and medium-sized arteries in hypertensive and normotensive subjects. Several clinical and animal studies have shown that arterial wall hypertrophy, which normalizes circumferential wall stress, does not increase the elastic modulus of arterial wall material during chronic essential hypertension. The structural changes associated with hypertension and those associated with aging have opposite effects on arterial distensibility at a given transmural pressure (isobaric distensibility): arterial distensibility increases with hypertension and decreases with aging. Thus, hypertension cannot be considered equivalent to aging. The structural and functional changes in arterial wall material associated with hypertension-induced hypertrophy may explain why medium-sized arteries maintain their distensibility characteristics despite a distending pressure increase; these changes may not be associated with an intrinsic (isobaric) decrease in the distensibility of large arteries.

Central pulse pressure is a major determinant of ascending aorta dilation in Marfan syndrome

BACKGROUND

In patients with Marfan syndrome (MFS), brachial pulse pressure (PP) has been recognized as a risk factor for aortic dilatation, leading to aortic dissection, the main cause of premature death. However, the relationships between aortic PP, aortic stiffness, and aortic root dilation have not been investigated. Our main objective was to determine whether central PP, which takes into account wave reflections and aortic stiffness, is a better determinant of ascending aorta diameter than brachial PP in MFS patients.

METHODS AND RESULTS

Twenty patients with confirmed MFS and 20 age- and sex-matched control subjects were included in this cross-sectional, noninvasive study. Elastic properties of the abdominal aorta and common carotid, common femoral, and radial arteries were calculated from the pulsatile changes in arterial diameter and pressure. The ascending aorta diameter, measured with conventional echocardiography, was 37% larger in MFS than in control subjects (P<0.001). Arterial distensibility was 38% lower in MFS than in control subjects at the site of the abdominal aorta (P<0.01) but not at other sites (common carotid, common femoral, and radial arteries). Independently of age and body surface area, ascending aorta diameter was positively correlated with carotid PP in MFS (P<0. 01) and negatively in control subjects (P<0.01) but was not correlated with brachial PP and mean blood pressure.

CONCLUSIONS

In patients with MFS, local PP, estimated from carotid PP, was a major determinant of ascending aorta diameter, whereas brachial PP was not. Increased arterial stiffness was confined to the aorta.

[Methods for exploring arteries in humans: application to the study of estrogens]

In recent years, two concepts--endothelial dysfunction and arterial remodelling--have emerged as keys to the understanding of the pathophysiology of the arterial system. The clinical investigation of endothelial dysfunction and arterial remodelling became a requisite for understanding the effects of any drug acting on the arterial wall, such as oestrogens during oestrogen replacement therapy. In this paper, we describe the various non-invasive methods for studying the geometry and the function of large and small arteries. Recent technological and methodological improvements allow this investigation to be carried out with satisfactory repeatability, and to be applied to clinical pharmacology. We also discuss the few studies which have applied these methods to the study of the effect of oestrogens on the arterial system and we suggest a physiological schema for an integrative mechanism of action.

Incremental conductance levels of GABAA receptors in dopaminergic neurones of the rat substantia nigra pars compacta

1. Molecular and biophysical properties of GABAA receptors of dopaminergic (DA) neurones of the pars compacta of the rat substantia nigra were studied in slices and after acute dissociation. 2. Single-cell reverse transcriptase-multiplex polymerase chain reaction confirmed that DA neurones contained mRNAs encoding for the alpha3 subunit of the GABAA receptor, but further showed the presence of alpha4 subunit mRNAs. alpha2, beta1 and gamma1 subunit mRNAs were never detected. Overall, DA neurones present a pattern of expression of GABAA receptor subunit mRNAs containing mainly alpha3/4beta2/3gamma3. 3. Outside-out patches were excised from DA neurones and GABAA single-channel patch-clamp currents were recorded under low doses (1-5 microM) of GABA or isoguvacine, a selective GABAA agonist. Recordings presented several conductance levels which appeared to be integer multiples of an elementary conductance of 4-5 pS. This property was shared by GABAA receptors of cerebellar Purkinje neurones recorded in slices (however, with an elementary conductance of 3 pS). Only the 5-6 lowest levels were analysed. 4. A progressive change in the distribution of occupancy of these levels was observed when increasing the isoguvacine concentration (up to 10 microM) as well as when adding zolpidem (20-200 nM), a drug acting at the benzodiazepine binding site: both treatments enlarged the occupancy of the highest conductance levels, while decreasing that of the smallest ones. Conversely, Zn2+ (10 microM), a negative allosteric modulator of GABAA receptor channels, decreased the occupancy of the highest levels in favour of the lowest ones. 5. These properties of alpha3/4beta2/3gamma3-containing GABAA receptors would support the hypothesis of either single GABAA receptor channels with multiple open states or that of a synchronous recruitment of GABAA receptor channels that could involve their clustering in the membranes of DA neurones.

Sub-Tenon's block: the effect of hyaluronidase on speed of onset and block quality

The role of hyaluronidase on the onset time and quality of single quadrant sub-Tenon's block was studied in a prospective, randomized, double-blind controlled manner. One hundred and twenty consecutive patients undergoing cataract surgery under local anaesthesia received a sub-Tenon's block with either of two local anaesthetic solutions. One consisted of 2% plain lignocaine 3 ml with 0.5% plain bupivacaine 2 ml. The other consisted of 2% lignocaine 1 ml containing 150 i.u. per ml of hyaluronidase with 2% plain lignocaine 2 ml and 0.5% plain bupivacaine 2 ml. The development of akinesia and the resulting block quality were assessed. Akinesia scores were lower at all time intervals and were significantly lower (P < 0.05) up to 9 minutes after block in the hyaluronidase group. However, block quality as assessed by the surgeon was not significantly different between the groups. The addition of 150 IU hyaluronidase significantly speeds up the onset of surgical anaesthesia produced by a sub-Tenon's block.

[Impact of essential hypertension on the arteries]

Arterial remodeling has emerged as a key-concept in the pathophysiology of hypertension and its vascular damage. In any given arterial territory, hypertension-induced remodeling is characterized by an increased intima-media thickness, independently of the lumen and wall cross-sectional areas. Functional consequences of hypertension-induced arterial remodeling depend upon the caliber of the artery, and thus upon its function. In essential hypertension, the 2 major functional consequences of large artery remodeling are the long-term enhancement of atherosclerosis and the shorter-term preservation of elastic properties. The functional consequences of resistive arteries remodeling can be either deleterious (structural increase in peripheral vascular resistances, hyperreactivity to vasomotor stimuli, and decrease in perfusion reserve of target organs) or rather compensatory (changes in the autoregulation of regional perfusions).