Brachial or wrist blood pressure in obese patients : which is the best ?

RESUME L'obésité et l'hypertension atteignent des niveaux épidémiques aussi bien dans les pays industrialisés que dans ceux en voie de développement. La coexistence de ces deux pathologies est associée à un risque cardiovasculaire augmenté. Traditionnellement on mesure la pression artérielle (PA) au bras au moyen d'un brassard qui détermine la pression systolique et diastolique en utilisant soit la méthode auscultatoire ou oscillométrique. L'utilisation d'un brassard de taille standard chez le patient avec un tour de bras augmenté peut surestimer la pression artérielle. Il semble même qu'il existe un rapport idéal entre le tour de bras, et la taille du brassard La mesure à domicile de la pression artérielle avec des appareils validés donne des valeurs de la PA valables. Plusieurs appareils existent sur le marché et depuis quelques années les appareils de mesure de la PA au poignet font leur apparition sur le marché. Cette étude vise à comparer chez des sujets sains et obèses les valeurs de PA obtenues au poignet avec celles obtenues au bras en utilisant deux appareils validés l'OMRON HEM 705-CP et l'OMRON R6. L'OMRON HEM 705-CP permet l'utilisation soit d'un brassard standard (13x30 cm) ou d'un brassard large (16x38 cm), et l'OMRON R6 mesure la PA au poignet. Nous avons comparé un groupe de sujets obèses [Body Mass Index (BMI) >35kg/m2] avec un groupe de sujets sains (BMI <25kg/m2). Ont été exclues de l'étudé les personnes prenant un traitement antihypertenseur ainsi que celles souffrant d'arythmies. La PA a été mesurée en position assise avec le bras gauche sur une table à hauteur du coeur. Un brassard large a été employé pour les sujets obèses et un brassard standard pour les sujets sains. Trois mesures ont été effectuées, la première après une pause de 5 min et chacune des suivantes avec un intervalle de 2 min. La pression d'inflation maximale a été fixée à 170 mmHg. Nous avons utilisé la formule proposée par Marks LA et al pour déterminer si le rapport entre la taille des brassards fournis avec l'OMRON .HEM 705-CP et le tour de bras de nos sujets était optimal (taille du brassard = 9.34 x log10 taille du bras). Nos résultats ne montrent pas de différence statistiquement significative de la PA diastolique entre les deux groupes, qu'elle soit mesurée au bras ou au poignet. La PA systolique mesurée au bras s'est par contre avérée significativement plus basse chez les sujets obèses que chez les sujets sains. Aucune différence n'a été trouvée lorsque la mesure est effectuée au poignet. En utilisant la formule fournie par Marks le rapport entre taille du brassard (large chez les obèses) et tour de bras a été de 10.30±30 chez les sujets obèses et 9.630.45 chez les sujets sains (p<0.001). Le rapport entre tour de bras et brassard chez les sujets obèses est nettement au-dessus de la valeur optimale, ce qui suggère une possible sous-estimation de la PA systolique chez ces sujets. Ces résultats suggèrent qu'il existe un risque de sous-estimer la PA chez le patient obèse lors de l'utilisation d'un brassard large. Cette erreur pourrait être réduite par l'utilisation d'appareils de mesure au poignet. validés chez le sujet obèse.

Cardiac hypertrophy, low blood pressure, and low aldosterone levels in mice devoid of the three circadian PAR bZip transcription factors DBP, HLF, and TEF.

The cardiovascular system is under the control of the circadian clock, and disturbed circadian rhythms can induce cardiovascular pathologies. This cyclic regulation is probably brought about by the circadian expression of genes encoding enzymes and regulators involved in cardiovascular functions. We have previously shown that the rhythmic transcription of output genes is, in part, regulated by the clock-controlled PAR bZip transcription factors DBP (albumin D-element Binding Protein), HLF (Hepatic Leukemia Factor), and TEF (Thyrotroph Embryonic Factor). The simultaneous deletion of all three PAR bZip transcription factors leads to increased morbidity and shortened life span. Here, we demonstrate that Dbp/Tef/Hlf triple knockout mice develop cardiac hypertrophy and left ventricular dysfunction associated with a low blood pressure. These dysfunctions are exacerbated by an abnormal response to this low blood pressure characterized by low aldosterone levels. The phenotype of PAR bZip knockout mice highlights the importance of circadian regulators in the modulation of cardiovascular functions.

Detection of metabolite induction in fungal co-cultures on solid media by high-throughput differential ultra-high pressure liquid chromatography-time-of-flight mass spectrometry fingerprinting.

Access to new biological sources is a key element of natural product research. A particularly large number of biologically active molecules have been found to originate from microorganisms. Very recently, the use of fungal co-culture to activate the silent genes involved in metabolite biosynthesis was found to be a successful method for the induction of new compounds. However, the detection and identification of the induced metabolites in the confrontation zone where fungi interact remain very challenging. To tackle this issue, a high-throughput UHPLC-TOF-MS-based metabolomic approach has been developed for the screening of fungal co-cultures in solid media at the petri dish level. The metabolites that were overexpressed because of fungal interactions were highlighted by comparing the LC-MS data obtained from the co-cultures and their corresponding mono-cultures. This comparison was achieved by subjecting automatically generated peak lists to statistical treatments. This strategy has been applied to more than 600 co-culture experiments that mainly involved fungal strains from the Fusarium genera, although experiments were also completed with a selection of several other filamentous fungi. This strategy was found to provide satisfactory repeatability and was used to detect the biomarkers of fungal induction in a large panel of filamentous fungi. This study demonstrates that co-culture results in consistent induction of potentially new metabolites.

Circadian glomerular function: from physiology to molecular and therapeutical aspects.

Life on earth is rhythmic by essence due to day/night alternation, and many biological processes are also cyclic. The kidney has a special role in the organism, controlling electrolytes and water balance, blood pressure, elimination of metabolic waste and xenobiotics and the production of several hormones. The kidney is submitted to changes throughout 24 h with periods of intense activity followed by calmer periods. Filtration, reabsorption and secretion are the three components determining renal function. Here, we review circadian changes related to glomerular function and proteinuria and emphasize the role of the clock in these processes.

Association between growth and blood pressure during the life course in children and adolescents

Background: Little is known on the relative importance of growth at different periods between birth and adolescence on blood pressure (BP). Objective: To assess the association between birth weight, change in body weight (growth) and BP across the entire span of childhood and adolescence. Methods: School-based surveys were conducted annually between 1998 and 2006 among all children in four school grades (kindergarten, 4th, 7th, and 10th year of compulsory school) in the Seychelles, Indian Ocean. Height and weight and BP were measured. Three cohorts of children examined twice were analyzed: 1606 children surveyed at age 5.5 and 9.1, 2557 at age 9.2 and 12.5, and 2065 at age 12.5 and 15.5, respectively. Weights at birth and at one year were extracted from medical files. Weights were expressed as Z-scores and growth was defined as a change in weight Z-scores (corresponding to weight centile crossing). The association between BP (at age 5.5, 9.2, 12.5, and 15.5) and weight at different times was assessed by linear regression. Using results of regression models of BP on all successive weights, life course plots were drawn by plotting regression coefficients against age at which weight was measured. The figure shows a life course plot of systolic BP in boys aged 15.5. Results: Without adjustment for current weight (at the time of BP measurement), birth weight was not associated with current BP, irrespective of age, excepted for girls at age 15.5 for whom a modest positive association was found. When adjusted for current weight, birth weight was negatively and modestly associated with current BP. BP was strongly associated with current weight, irrespective of age. Life course plots showed that BP was strongly associated with growth during the few preceding years but not with growth during earlier years, except for growth during the first year of life which tended to be associated with systolic BP. Conclusions: Our findings suggest that BP during childhood and adolescence is mainly determined by current body weight and recent growth.

Upward hypertension trends: changes in blood pressure or in antihypertensive treatment?

Comment on: Cutler JA, Sorlie PD, Wolz M, Thom T, Fields LE, Roccella EJ. Trends in hypertension prevalence, awareness, treatment, and control rates in United States adults between 1988-1994 and 1999-2004. Hypertension. 2008 Nov;52(5):818-27. PMID: 18852389.

Blood pressure-independent cardiac hypertrophy induced by locally activated renin-angiotensin system.

Cardiac hypertrophy is frequent in chronic hypertension. The renin-angiotensin system, via its effector angiotensin II (Ang II), regulates blood pressure and participates in sustaining hypertension. In addition, a growing body of evidence indicates that Ang II acts also as a growth factor. However, it is still a matter of debate whether the trophic effect of Ang II can trigger cardiac hypertrophy in the absence of elevated blood pressure. To address this question, transgenic mice overexpressing the rat angiotensinogen gene, specifically in the heart, were generated to increase the local activity of the renin-angiotensin system and therefore Ang II production. These mice develop myocardial hypertrophy without signs of fibrosis independently from the presence of hypertension, demonstrating that local Ang II production is important in mediating the hypertrophic response in vivo.

Reactive rise in blood pressure upon cuff inflation: cuff inflation at the arm causes a greater rise in pressure than at the wrist in hypertensive patients.

OBJECTIVE: Cuff inflation at the arm is known to cause an instantaneous rise in blood pressure, which might be due to the discomfort of the procedure and might interfere with the precision of the blood pressure measurement. In this study, we compared the reactive rise in blood pressure induced by cuff inflation when the cuff was placed at the upper arm level and at the wrist. PARTICIPANTS AND METHODS: The reactive rise in systolic and diastolic blood pressure to cuff inflation was measured in 34 normotensive participants and 34 hypertensive patients. Each participant was equipped with two cuffs, one around the right upper arm (OMRON HEM-CR19, 22-32 cm) and one around the right wrist (OMRON HEM-CS 19, 17-22 cm; Omron Health Care Europe BV, Hoofddorp, The Netherlands). The cuffs were inflated in a double random order (maximal cuff pressure and position of the cuff) with two maximal cuff pressures: 180 and 240 mmHg. The cuffs were linked to an oscillometric device (OMRON HEM 907; Omron Health Care). Simultaneously, blood pressure was measured continuously at the middle finger of the left hand using photoplethysmography. Three measurements were made at each level of blood pressure at the arm and at the wrist, and the sequence of measurements was randomized. RESULTS: In normotensive participants, no significant difference was observed in the reactive rise in blood pressure when the cuff was inflated either at the arm or at the wrist irrespective of the level of cuff inflation. Inflating a cuff at the arm, however, induced a significantly greater rise in blood pressure than inflating it at the wrist in hypertensive participants for both systolic and diastolic pressures (P<0.01), and at both levels of cuff inflation. The blood pressure response to cuff inflation was independent of baseline blood pressure. CONCLUSIONS: The results show that in hypertensive patients, cuff inflation at the wrist produces a smaller reactive rise in blood pressure. The difference between the arm and the wrist is independent of the patient's level of blood pressure.

The effect of positive airway pressure during pre-oxygenation and induction of anaesthesia upon duration of non-hypoxic apnoea

Résumé de l'étude. L'application d'une pression positive (PEEP) pendant la phase d'induction d'une anesthésie générale peut prévenir la formation d'atélectasies pulmonaires. Ceci pourrait permettre d'accroître la durée d'apnée non hypoxique par l'augmentation de la capacité pulmonaire résiduelle fonctionnelle (CRF). Nous avons étudié le bénéfice de l'application d'une PEEP durant la phase d'induction d'une anesthésie générale sur la durée d'apnée avant que la saturation périphérique en oxygène atteigne 90%. Quarante patients ASA I-II ont été randomisés en deux groupes distincts. - Dans le groupe PEEP (n=20), les patients ont été pré-oxygénés durant 5 minutes avec une Fi02 à l00% par l'intermédiaire d'un appareil de CPAP (6cmH2O). Après induction de l'anesthésie, les patients furent ventilés mécaniquement (PEEP 6cmH2O) durant 5 minutes supplémentaires. - Dans le groupe ZEEP (n=20), aucune pression positive (ni CPAP, ni PEEP) ne fut utilisée. La durée d'apnée pour atteindre une saturation périphérique de 90% fut mesurée. La durée d'apnée non hypoxique était plus longue dans le groupe PEEP par rapport au groupe ZEEP (599 +/- 135 s vs 470 +/- 150 s, p= 0,007). Nous concluons que l'application d'une pression positive durant la phase d'induction d'une anesthésie générale chez l'adulte prolonge la durée d'apnée non hypoxique de plus de 2 minutes.

Transcutaneous carbon dioxide pressure for monitoring patients with severe croup.

In a prospective investigation of 17 children with severe croup, we analyzed the effect of epinephrine inhalations and mild sedation with chloral hydrate on transcutaneous carbon dioxide pressure (tcPCO2), pulse oximetry measurements, and croup scores. There was a highly significant reduction (p less than 0.001) in the tcPCO2 values and croup scores after inhalation of epinephrine. The changes in the tcPCO2 values correlated with the clinical findings. Mild sedation also significantly improved the croup scores but failed to influence the tcPCO2 values. There was not statistically significant difference in pulse oximetry saturation, fraction of administered oxygen, heart rate, or respiratory rate before and after inhalation of epinephrine or chloral hydrate administration. Monitoring tcPCO2 appears to be a reliable and objective tool for managing patients with upper airway obstruction, whereas croup scores may be misleading.

Profiling of steroid metabolites after transdermal and oral administration of testosterone by ultra-high pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry.

The screening of testosterone (T) misuse for doping control is based on the urinary steroid profile, including T, its precursors and metabolites. Modifications of individual levels and ratio between those metabolites are indicators of T misuse. In the context of screening analysis, the most discriminant criterion known to date is based on the T glucuronide (TG) to epitestosterone glucuronide (EG) ratio (TG/EG). Following the World Anti-Doping Agency (WADA) recommendations, there is suspicion of T misuse when the ratio reaches 4 or beyond. While this marker remains very sensitive and specific, it suffers from large inter-individual variability, with important influence of enzyme polymorphisms. Moreover, use of low dose or topical administration forms makes the screening of endogenous steroids difficult while the detection window no longer suits the doping habit. As reference limits are estimated on the basis of population studies, which encompass inter-individual and inter-ethnic variability, new strategies including individual threshold monitoring and alternative biomarkers were proposed to detect T misuse. The purpose of this study was to evaluate the potential of ultra-high pressure liquid chromatography (UHPLC) coupled with a new generation high resolution quadrupole time-of-flight mass spectrometer (QTOF-MS) to investigate the steroid metabolism after transdermal and oral T administration. An approach was developed to quantify 12 targeted urinary steroids as direct glucuro- and sulfo-conjugated metabolites, allowing the conservation of the phase II metabolism information, reflecting genetic and environmental influences. The UHPLC-QTOF-MS(E) platform was applied to clinical study samples from 19 healthy male volunteers, having different genotypes for the UGT2B17 enzyme responsible for the glucuroconjugation of T. Based on reference population ranges, none of the traditional markers of T misuse could detect doping after topical administration of T, while the detection window was short after oral TU ingestion. The detection ability of the 12 targeted steroids was thus evaluated by using individual thresholds following both transdermal and oral administration. Other relevant biomarkers and minor metabolites were studied for complementary information to the steroid profile, including sulfoconjugated analytes and hydroxy forms of glucuroconjugated metabolites. While sulfoconjugated steroids may provide helpful screening information for individuals with homozygotous UGT2B17 deletion, hydroxy-glucuroconjugated analytes could enhance the detection window of oral T undecanoate (TU) doping.

Birth weight, weight change, and blood pressure during childhood and adolescence: a school-based multiple cohort study.

OBJECTIVE: We assessed the association between birth weight, weight change, and current blood pressure (BP) across the entire age-span of childhood and adolescence in large school-based cohorts in the Seychelles, an island state in the African region. METHODS: Three cohorts were analyzed: 1004 children examined at age 5.5 and 9.1 years, 1886 children at 9.1 and 12.5, and 1575 children at 12.5 and 15.5, respectively. Birth and 1-year anthropometric data were gathered from medical files. The outcome was BP at age 5.5, 9.1, 12.5 or 15.5 years, respectively. Conditional linear regression analysis was used to estimate the relative contribution of changes in weight (expressed in z-score) during different age periods on BP. All analyses were adjusted for height. RESULTS: At all ages, current BP was strongly associated with current weight. Birth weight was not significantly associated with current BP. Upon adjustment for current weight, the association between birth weight and current BP tended to become negative. Conditional linear regression analyses indicated that changes in weight during successive age periods since birth contributed substantially to current BP at all ages. The strength of the association between weight change and current BP increased throughout successive age periods. CONCLUSION: Weight changes during any age period since birth have substantial impact on BP during childhood and adolescence, with BP being more responsive to recent than earlier weight changes.