[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.