Whole blood NAD and NADP concentrations are not depressed in subjects with clinical pellagra

Population surveys for niacin deficiency are normally based on clinical signs or on biochemical measurements of urinary niacin metabolites. Status may also be determined by measurement of whole blood NAD and NADP concentrations. To compare these methods, whole blood samples and spot urine samples were collected from healthy subjects (n = 2) consuming a western diet, from patients (n = 34) diagnosed with pellagra and attending a pellagra clinic in Kuito (central Angola, where niacin deficiency is endemic), and from female community control subjects (n = 107) who had no clinical signs of pellagra. Whole blood NAD and NADP concentrations were measured by microtiter plate-based enzymatic assays and the niacin urinary metabolites 1-methyl-2-pyridone-5-carboxamide (2-PYR) and 1-methylnicotinamide (1-MN) by HPLC. In healthy volunteers, inter- and intra-day variations for NAD and NADP concentrations were much lower than for the urinary metabolites, suggesting a more stable measure of status. However, whole blood concentrations of NAD and NADP or the NAD:NADP ratio were not significantly depressed in clinical pellagra. In contrast, the concentrations of 2-PYR and 1-MN, expressed relative to either creatinine or osmolality, were lower in pellagra patients and markedly higher following treatment. The use of the combined cut-offs (2-PYR <3.0 micromol/mmol creatinine and 1-MN <1.3 micromol/mmol creatinine) gave a sensitivity of 91% and specificity of 72%. In conclusion, whole blood NAD and NADP concentrations gave an erroneously low estimate of niacin deficiency. In contrast, spot urine sample 2-PYR and 1-MN concentrations, relative to creatinine, were a sensitive and specific measure of deficiency

Low and deficient niacin status and pellagra are endemic in postwar Angola

BACKGROUND: Outbreaks of pellagra were documented during the civil war in Angola, but no contemporary data on the incidence of pellagra or the prevalence of niacin deficiency were available. OBJECTIVE: The objective was to investigate the incidence of pellagra and the prevalence of niacin deficiency in postwar Angola and their relation with dietary intake, poverty, and anthropometric status. DESIGN: Admissions data from 1999 to 2004 from the pellagra treatment clinic in Kuito, Angola, were analyzed. New patients admitted over 1 wk were examined, and urine and blood samples were collected. A multistage cluster population survey collected data on anthropometric measures, household dietary intakes, socioeconomic status, and clinical signs of pellagra for women and children. Urinary excretion of 1-methylnicotinamide, 1-methyl-2-pyridone-5-carboxymide, and creatinine was measured and hemoglobin concentrations were measured with a portable photometer. RESULTS: The incidence of clinical pellagra has not decreased since the end of the civil war in 2002. Low excretion of niacin metabolites was confirmed in 10 of 11 new clinic patients. Survey data were collected for 723 women aged 15-49 y and for 690 children aged 6-59 mo. Excretion of niacin metabolites was low in 29.4% of the women and 6.0% of the children, and the creatinine-adjusted concentrations were significantly lower in the women than in the children (P < 0.001, t test). In children, niacin status was positively correlated with the household consumption of peanuts (r = 0.374, P = 0.001) and eggs (r = 0.290, P = 0.012) but negatively correlated with socioeconomic status (r = -0.228, P = 0.037). CONCLUSIONS: The expected decrease in pellagra incidence after the end of the civil war has not occurred. The identification of niacin deficiency as a public health problem should refocus attention on this nutritional deficiency in Angola and other areas of Africa where maize is the staple

Abdominal muscle fatigue following exercise in chronic obstructive pulmonary disease

<p>Abstract</p> <p>Background</p> <p>In patients with chronic obstructive pulmonary disease, a restriction on maximum ventilatory capacity contributes to exercise limitation. It has been demonstrated that the diaphragm in COPD is relatively protected from fatigue during exercise. Because of expiratory flow limitation the abdominal muscles are activated early during exercise in COPD. This adds significantly to the work of breathing and may therefore contribute to exercise limitation. In healthy subjects, prior expiratory muscle fatigue has been shown itself to contribute to the development of quadriceps fatigue. It is not known whether fatigue of the abdominal muscles occurs during exercise in COPD.</p> <p>Methods</p> <p>Twitch gastric pressure (TwT10Pga), elicited by magnetic stimulation over the 10^ththoracic vertebra and twitch transdiaphragmatic pressure (TwPdi), elicited by bilateral anterolateral magnetic phrenic nerve stimulation were measured before and after symptom-limited, incremental cycle ergometry in patients with COPD.</p> <p>Results</p> <p>Twenty-three COPD patients, with a mean (SD) FEV₁40.8(23.1)% predicted, achieved a mean peak workload of 53.5(15.9) W. Following exercise, TwT₁₀Pga fell from 51.3(27.1) cmH₂O to 47.4(25.2) cmH₂O (p = 0.011). TwPdi did not change significantly; pre 17.0(6.4) cmH₂O post 17.5(5.9) cmH₂O (p = 0.7). Fatiguers, defined as having a fall TwT10Pga ≥ 10% had significantly worse lung gas transfer, but did not differ in other exercise parameters.</p> <p>Conclusions</p> <p>In patients with COPD, abdominal muscle but not diaphragm fatigue develops following symptom limited incremental cycle ergometry. Further work is needed to establish whether abdominal muscle fatigue is relevant to exercise limitation in COPD, perhaps indirectly through an effect on quadriceps fatigability.</p

Respiratory muscle strength as a predictive biomarker for survival in amyotrophic lateral sclerosis

Rationale: Biomarkers for survival in amyotrophic lateral sclerosis (ALS) would facilitate the development of novel drugs. Although respiratory muscle weakness is a known predictor of poor prognosis, a comprehensive comparison of different tests is lacking. Objectives: To compare the predictive power of invasive and noninvasive respiratory muscle strength assessments for survival or ventilator-free survival, up to 3 years. Methods: From a previously published report respiratory muscle strength measurements were available for 78 patients with ALS. Time to death and/or ventilation were ascertained. Receiver operating characteristic analysis was used to determine the cutoff point of each parameter. Measurements and Main Results: Each respiratory muscle strength assessment individually achieved statistical significance for prediction of survival or ventilator-free survival. In multivariate analysis sniff trans-diaphragmatic and esophageal pressure, twitch trans-diaphragmatic pressure (Tw Pdi), age, and maximal static expiratory mouth pressure were significant predictors of ventilation-free survival and Tw Pdi and maximal static expiratory mouth pressure for absolute survival. Although all measures had good specificity, there were differing sensitivities. All cutoff points for the VC were greater than 80% of normal, except for prediction of 3-month outcomes. Sequential data showed a linear decline for direct measures of respiratory muscle strength, whereas VC showed little to no decline until 12 months before death/ventilation. Conclusions: The most powerful biomarker for mortality stratification was Tw Pdi, but the predictive power of sniff nasal inspiratory pressure was also excellent. A VC within normal range suggested a good prognosis at 3 months but was of little other value

Effect of acute hypoxia on respiratory muscle fatigue in healthy humans

<p>Abstract</p> <p>Background</p> <p>Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue.</p> <p>Methods</p> <p>Twelve healthy males performed three 15-min isocapnic hyperpnoea tests (85% of maximum voluntary ventilation with controlled breathing pattern) in normoxic, hypoxic (SpO₂= 80%) and hyperoxic (FiO₂= 0.60) conditions, in a random order. Before, immediately after and 30 min after hyperpnoea, transdiaphragmatic pressure (P_di,tw) was measured during cervical magnetic stimulation to assess diaphragm contractility, and gastric pressure (P_ga,tw) was measured during thoracic magnetic stimulation to assess abdominal muscle contractility. Two-way analysis of variance (time x condition) was used to compare hyperpnoea-induced respiratory muscle fatigue between conditions.</p> <p>Results</p> <p>Hypoxia enhanced hyperpnoea-induced P_di,twand P_ga,twreductions both immediately after hyperpnoea (P_di,tw: normoxia -22 ± 7% vs hypoxia -34 ± 8% vs hyperoxia -21 ± 8%; P_ga,tw: normoxia -17 ± 7% vs hypoxia -26 ± 10% vs hyperoxia -16 ± 11%; all <it>P </it>< 0.05) and after 30 min of recovery (P_di,tw: normoxia -10 ± 7% vs hypoxia -16 ± 8% vs hyperoxia -8 ± 7%; P_ga,tw: normoxia -13 ± 6% vs hypoxia -21 ± 9% vs hyperoxia -12 ± 12%; all <it>P </it>< 0.05). No significant difference in P_di,twor P_ga,twreductions was observed between normoxic and hyperoxic conditions. Also, heart rate and blood lactate concentration during hyperpnoea were higher in hypoxia compared to normoxia and hyperoxia.</p> <p>Conclusions</p> <p>These results demonstrate that hypoxia exacerbates both diaphragm and abdominal muscle fatigability. These results emphasize the potential role of respiratory muscle fatigue in exercise performance limitation under conditions coupling increased work of breathing and reduced O₂transport as during exercise in altitude or in hypoxemic patients.</p

Infiltration et alimentation des aquifères alluviaux : détermination du coefficient d'infiltration dans la Combe de Savoie - Alpes françaises

La présente étude est un essai d'évaluation du bilan hydrologique d'une plaine alluviale pour une période de cinq ans (19721976) de mesures. Plus particulièrement, le but de cette étude est de déterminer le coefficient d'infiltration d'une plaine alluviale afin de pouvoir mesurer l'infiltration dans cette région. Ayant choisi une plaine alluviale (Combe de Savoie) du bassin de l'Isère, nous étudierons la géologie des différentes formations alluviales de cette plaine. Nous essayerons de déterminer les différents facteurs de l'hydrologie et de la climatologie du domaine d'étude (précipitations.évapotranspiration, climat). Nous examinerons le comportement hydrogéologique de la nappe aquifère contenue dans les alluvions (les différents types d'alimentation, de circulation et de variations de la nappe). Nous exposerons les données géophysiques existantes concernant notre région et pour calculer le coefficient d'infiltration, nous choisirons trois secteurs différents où nous évaluerons ce facteur. Après, nous tâcherons de déterminer le coefficient d'infiltration de l'ensemble du bassin. Ayant mesuré le coefficient d'infiltration, nous déterminerons l'infiltration et nous établirons le bilan hydrologique de notre région. Enfin, nous essayerons d'établir une relation entre les précipitations et l'infiltration de ce bassin (par méthode statistique) afin d'établir la loi des variations de cette dernière en fonction de la pluie.Pas de résum

Inspiratory and expiratory muscle function under load

Available from British Library Document Supply Centre- DSC:DXN061043 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Inspiratory muscle maximum relaxation rate measured from submaximal sniff nasal pressure in patients with severe COPD

Background: Slowing of the inspiratory muscle maximum relaxation rate (MRR) is a useful index of severe inspiratory muscle loading and potential fatigue and has been measured from the oesophageal pressure during sniffs in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study was to investigate whether it is possible to measure MRR and detect slowing using sniff nasal pressure in patients with COPD and to investigate the relationship between sniff oesophageal and sniff nasal MRR. Methods: Eight patients with severe COPD (mean FEV(1) 0.7 l; 26% predicted) were studied. Each subject performed submaximal sniff manoeuvres before and after walking to a state of severe dyspnoea on a treadmill. Oesophageal and gastric pressures were measured using balloon tipped catheters and nasal pressure was measured using an individually modelled nasal cast. MRR (% pressure fall/10 ms) was determined for each sniff and any change following exercise was reported as percentage of baseline to allow comparison of sniff nasal and oesophageal MRR. Results: At rest the mean (SE) sniff Poes MRR was 7.1 (0.3) and the mean Pnasal MRR was 8.6 (0.1). At 1 minute following exercise there was a mean decrease in sniff Poes MRR of 33.7% (range 20.7–53.4%) and a mean decrease in sniff Pnasal MRR of 28.2% (range 8.1–52.8%). The degree of slowing and time course of recovery was similar, with both returning to baseline values within 5–10 minutes. A separate analysis of the sniff pressures using only the nasal pressure traces demonstrated a similar pattern of slowing and recovery. Conclusions: It is possible to detect slowing of the inspiratory muscles non-invasively using sniff nasal pressures in patients with COPD. This could be a useful technique with which to measure severe and potentially fatiguing inspiratory muscle loading, both in clinical settings and during exercise studies