Ambient hypoxia enhances the loss of muscle mass after extensive injury.

Hypoxia induces a loss of skeletal muscle mass and alters myogenesis in vitro, but whether it affects muscle regeneration in vivo following injury remains to be elucidated. We hypothesized that hypoxia would impair the recovery of muscle mass during regeneration. To test this hypothesis, the soleus muscle of female rats was injured by notexin and allowed to recover for 3, 7, 14, and 28 days under normoxia or hypobaric hypoxia (5,500 m) conditions. Hypoxia impaired the formation and growth of new myofibers and enhanced the loss of muscle mass during the first 7 days of regeneration, but did not affect the final recovery of muscle mass at 28 days. The impaired regeneration under hypoxic conditions was associated with a blunted activation of mechanical target of rapamycin (mTOR) signaling as assessed by p70(S6K) and 4E-BP1 phosphorylation that was independent of Akt activation. The decrease in mTOR activity with hypoxia was consistent with the increase in AMP-activated protein kinase activity, but not related to the change in regulated in development and DNA response 1 protein content. Hypoxia increased the mRNA levels of the atrogene muscle ring finger-1 after 7 days of regeneration, though muscle atrophy F box transcript levels remained unchanged. The increase in MyoD and myogenin mRNA expression with regeneration was attenuated at 7 days with hypoxia. In conclusion, our results support the notion that the enhanced loss of muscle mass observed after 1 week of regeneration under hypoxic conditions could mainly result from the impaired formation and growth of new fibers resulting from a reduction in protein synthesis and satellite cell activity.

Effect of hypoxia exposure on the recovery of skeletal muscle phenotype during regeneration.

Hypoxia impairs the muscle fibre-type shift from fast-to-slow during post-natal development; however, this adaptation could be a consequence of the reduced voluntary physical activity associated with hypoxia exposure rather than the result of hypoxia per se. Moreover, muscle oxidative capacity could be reduced in hypoxia, particularly when hypoxia is combined with additional stress. Here, we used a model of muscle regeneration to mimic the fast-to-slow fibre-type conversion observed during post-natal development. We hypothesised that hypoxia would impair the recovery of the myosin heavy chain (MHC) profile and oxidative capacity during muscle regeneration. To test this hypothesis, the soleus muscle of female rats was injured by notexin and allowed to recover for 3, 7, 14 and 28 days under normoxia or hypobaric hypoxia (5,500 m altitude) conditions. Ambient hypoxia did not impair the recovery of the slow MHC profile during muscle regeneration. However, hypoxia moderately decreased the oxidative capacity (assessed from the activity of citrate synthase) of intact muscle and delayed its recovery in regenerated muscle. Hypoxia transiently increased in both regenerated and intact muscles the content of phosphorylated AMPK and Pgc-1α mRNA, two regulators involved in mitochondrial biogenesis, while it transiently increased in intact muscle the mRNA level of the mitophagic factor BNIP3. In conclusion, hypoxia does not act to impair the fast-to-slow MHC isoform transition during regeneration. Hypoxia alters the oxidative capacity of intact muscle and delays its recovery in regenerated muscle; however, this adaptation to hypoxia was independent of the studied regulators of mitochondrial turn-over.

WHOLE GENOME TARGETED ENRICHMENT AND SEQUENCING OF HUMAN-INFECTING CRYPTOSPORIDIUM spp.

Cryptosporidium spp. are protozoan parasites that cause severe illness in vulnerable human populations. Obtaining pure Cryptosporidium DNA from clinical and environmental samples is challenging because the oocysts shed in contaminated feces are limited in quantity, difficult to purify efficiently, may derive from multiple species, and yield limited DNA (<40 fg/oocyst). Here, we develop and validate a set of 100,000 RNA baits (CryptoCap_100k) based on six human-infecting Cryptosporidium spp. (C. cuniculus, C. hominis, C. meleagridis, C. parvum, C. tyzzeri, and C. viatorum) to enrich Cryptosporidium spp. DNA from a wide array of samples. We demonstrate that CryptoCap_100k increases the percentage of reads mapping to target Cryptosporidium references in a wide variety of scenarios, increasing the depth and breadth of genome coverage, facilitating increased accuracy of detecting and analyzing species within a given sample, while simultaneously decreasing costs, thereby opening new opportunities to understand the complex biology of these important pathogens.

WHOLE GENOME TARGETED ENRICHMENT AND SEQUENCING OF HUMAN-INFECTING CRYPTOSPORIDIUM spp.

Cryptosporidium spp. are protozoan parasites that cause severe illness in vulnerable human populations. Obtaining pure Cryptosporidium DNA from clinical and environmental samples is challenging because the oocysts shed in contaminated feces are limited in quantity, difficult to purify efficiently, may derive from multiple species, and yield limited DNA (<40 fg/oocyst). Here, we develop and validate a set of 100,000 RNA baits (CryptoCap_100k) based on six human-infecting Cryptosporidium spp. ( C. cuniculus , C. hominis , C. meleagridis , C. parvum , C. tyzzeri , and C. viatorum ) to enrich Cryptosporidium spp. DNA from a wide array of samples. We demonstrate that CryptoCap_100k increases the percentage of reads mapping to target Cryptosporidium references in a wide variety of scenarios, increasing the depth and breadth of genome coverage, facilitating increased accuracy of detecting and analyzing species within a given sample, while simultaneously decreasing costs, thereby opening new opportunities to understand the complex biology of these important pathogens.

Comparison of four-year toxicities and local control of ultra-hypofractionated vs moderate-hypofractionated image guided prostate radiation with HDR brachytherapy boost: A phase I-II single institution trial.

Purpose/Objectives: To analyze the long term efficacy and safety of an ultra-hypofractionated (UHF) radiation therapy prostate treatment regimen with HDR brachytherapy boost (BB) and compare it to moderate-hypofractionated regimens (MHF). Materials/Methods: In this single arm, prospective monocentric study, 28 patients with intermediate risk prostate cancer were recruited in an experimental treatment arm of 25 Gy in 5 fractions plus a 15 Gy HDR BB. They were then compared to two historical control groups, treated with either 36 Gy in 12 fractions or 37.5 Gy in 15 fractions with a similar HDR BB. The control groups included 151 and 311 patients respectively. Patient outcomes were reported using the International Prostate Symptom Score (IPSS) and Expanded Prostate Index Composite (EPIC-26) questionnaires at baseline and at each follow-up visit. Results: Median follow-up for the experimental arm was 48.5 months compared to 47 months and 60 months compared to the 36/12 and 37,5/15 groups respectively. The IPSS and EPIC scores did not demonstrate any significant differences in the gastrointestinal or genitourinary domains between the three groups over time. No biochemical recurrence occurred in the UHF arm as defined by the Phoenix criterion. Conclusion: The UHF treatment scheme with HDR BB seems equivalent to standard treatment arms in terms of toxicities and local control. Randomized control trials with larger cohorts are ongoing and needed to further confirm our findings.

Pitfalls in target mRNA quantification for real-time quantitative RT-PCR in overload-induced skeletal muscle hypertrophy.

Quantifying target mRNA using real-time quantitative reverse transcription-polymerase chain reaction requires an accurate normalization method. Determination of normalization factors (NFs) based on validated reference genes according to their relative stability is currently the best standard method in most usual situations. This method controls for technical errors, but its physiological relevance requires constant NF values for a fixed weight of tissue. In the functional overload model, the increase in the total RNA concentration must be considered in determining the NF values. Here, we pointed out a limitation of the classical geNorm-derived normalization. geNorm software selected reference genes despite that the NF values extensively varied under experiment. Only the NF values calculated from four intentionally selected genes were constant between groups. However, a normalization based on these genes is questionable. Indeed, three out of four genes belong to the same functional class (negative regulator of muscle mass), and their use is physiological nonsense in a hypertrophic model. Thus, we proposed guidelines for optimizing target mRNA normalization and quantification, useful in models of muscle mass modulation. In our study, the normalization method by multiple reference genes was not appropriate to compare target mRNA levels between overloaded and control muscles. A solution should be to use an absolute quantification of target mRNAs per unit weight of tissue, without any internal normalization. Even if the technical variations will stay present as a part of the intergroup variations, leading to less statistical power, we consider this method acceptable because it will not generate misleading results.

A polysomnographic study of daytime sleepiness in myotonic dystrophy type 1.

OBJECTIVES: To assess contributors to excessive daytime sleepiness (EDS) in myotonic dystrophy type 1 (DM1), to characterise subjects with sleep-onset REM periods (SOREMPs), and to verify whether self-reported instruments and respiratory function tests can predict multiple sleep latency test (MSLT) and sleep-disordered breathing. METHODS: A sample of 43 DM1 patients without selection bias underwent polysomnography (PSG) for two consecutive nights and MSLT, completed a sleep diary and Epworth Sleepiness Scale (ESS), and were assessed for respiratory function and narcolepsy symptoms. RESULTS: ESS scores (ES) > or =11 and MSLT mean sleep latency (MSL) < or =8 min were found in 21 (50.0%) and 19 (44.2%) subjects, and either in 30 (69.8%) subjects. ES did not relate to MSL. Subjects with subjective sleepiness (ES> or =11) reported more cataplexy-like and sleep paralysis symptoms, longer habitual sleep times, and higher sleep efficiency and REM sleep per cent than those without. Subjects with objective sleepiness (MSL< or =8 min) had a higher stage 4 sleep per cent. Subjects with > or =2 SOREMPs (25.6%) showed higher muscular impairment, lower MSL, higher ES, and more cataplexy-like symptoms than those with < or =1 SOREMP. Apnoea-hypopnoea index (AHI) > or =5, predominantly obstructive, was found in 37 (86.0%) subjects, and AHI >30 in 12 (27.9%). Neither subjective nor objective sleepiness could be explained by AHI, nor satisfactorily predicted by daytime respiratory abnormalities. CONCLUSIONS: DM1 entails frequent EDS but with different phenotypes and distinct mechanisms involved. The high prevalence of daytime sleepiness and severe sleep apnoeas found in this study supports the routine use of clinical sleep interviews, PSG and MSLT in DM1, and emphasises the need for more randomised trials of psychostimulants.

Determinants of undernutrition in rural communities of a protected area in Gabon.

OBJECTIVE: To understand how access to natural resources may contribute to nutrition. DESIGN: In each of the two major seasons, data were collected during a 7 d period using observations, semi-structured interviews, anthropometric measures and a weighed food consumption survey. SETTING: Four rural communities selected to represent inland and coastal areas of the Gamba Complex in Gabon. SUBJECTS: In each community, all individuals from groups vulnerable to malnutrition, i.e. children aged 0-23 months (n 41) and 24-59 months (n 63) and the elderly (n 101), as well as women caregivers (n 96). RESULTS: In most groups, household access to natural resources was associated with household access to food but not with individual nutritional status. In children aged 0-23 months, access to care and to health services and a healthy environment were the best predictors of length-for-age (adjusted R2: 14%). Health status was the only predictor of weight-for-height in children aged 24-59 months (adjusted R2: 14%). In women caregivers, household food security was negatively associated with nutritional status, as was being younger than 20 years (adjusted R2: 16%). Among the elderly, only nutrient adequacy predicted nutritional status (adjusted R2: 5%). CONCLUSION: Improving access to care and health for young children would help reverse the process of undernutrition. Reaching a better understanding of how the access of individuals to both food and other resources relate to household access could further our appreciation of the constraints to good nutrition. This is particularly relevant in women to ensure that their possibly important contribution to the household is not at their own expense.

Nutritional status and dietary adequacy in rural communities of a protected area in Gabon.

OBJECTIVE: As part of a larger study designed to understand how to protect the food and nutrition security of individuals living in a protected area of Gabon, we assessed their nutritional status and its relationship to dietary adequacy and health status. DESIGN: A 7 d food consumption survey was conducted during each of the two major seasons using a weighing method. Data were also collected on weight, height and health of individuals as well as on sociodemographic characteristics and potential determinants of the nutrition situation. SETTING: Four rural communities were intentionally selected to represent both inland and coastal settings and access to food markets. SUBJECTS: Approximately 500 individuals representing over 90% of the population of these communities participated in the survey during each season. RESULTS: Undernutrition was present in the area, particularly among children <5 years of age and the elderly. Health was generally good and under-fives were most frequently ill. Energy, Fe and vitamin A requirements of individuals were generally not satisfied; the opposite was true for protein. The estimated prevalence of inadequate intakes of energy and vitamin A was very high in most age groups. Global nutrient adequacy was associated with nutritional outcome. CONCLUSIONS: Individuals do not eat enough and breast-feeding practices are poor. Many suffer from undernutrition, particularly young children and the elderly. The results confirm the need to investigate the determinants of this poor nutrition situation to ensure that protection of natural resources will not be associated with harm to the well-being of the population.

Brain stem NO modulates ventilatory acclimatization to hypoxia in mice.

The objective of our study was to assess the role of neuronal nitric oxide synthase (nNOS) in the ventilatory acclimatization to hypoxia. We measured the ventilation in acclimatized Bl6/CBA mice breathing 21% and 8% oxygen, used a nNOS inhibitor, and assessed the expression of N-methyl-d-aspartate (NMDA) glutamate receptor and nNOS (mRNA and protein). Two groups of Bl6/CBA mice (n = 60) were exposed during 2 wk either to hypoxia [barometric pressure (PB) = 420 mmHg] or normoxia (PB = 760 mmHg). At the end of exposure the medulla was removed to measure the concentration of nitric oxide (NO) metabolites, the expression of NMDA-NR1 receptor, and nNOS by real-time RT-PCR and Western blot. We also measured the ventilatory response [fraction of inspired O(2) (Fi(O(2))) = 0.21 and 0.08] before and after S-methyl-l-thiocitrulline treatment (SMTC, nNOS inhibitor, 10 mg/kg ip). Chronic hypoxia caused an increase in ventilation that was reduced after SMTC treatment mainly through a decrease in tidal volume (Vt) in normoxia and in acute hypoxia. However, the difference observed in the magnitude of acute hypoxic ventilatory response [minute ventilation (Ve) 8% - Ve 21%] in acclimatized mice was not different. Acclimatization to hypoxia induced a rise in NMDA receptor as well as in nNOS and NO production. In conclusion, our study provides evidence that activation of nNOS is involved in the ventilatory acclimatization to hypoxia in mice but not in the hypoxic ventilatory response (HVR) while the increased expression of NMDA receptor expression in the medulla of chronically hypoxic mice plays a role in acute HVR. These results are therefore consistent with central nervous system plasticity, partially involved in ventilatory acclimatization to hypoxia through nNOS.

Lipids and stroke: a paradox resolved.

BACKGROUND: Although dyslipidemia is a well established risk factor for coronary artery disease, its relationship to ischemic cerebrovascular disease has remained unclear, perhaps because of the heterogeneous nature of strokes. METHODS: In a case-control study, we measured the serum concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, serum triglycerides, and lipoprotein(a) levels and determined the apolipoprotein E phenotype and serum ferritin level in 90 consecutive systematically investigated patients with stroke or transient ischemic attack of atherothrombotic origin. Ninety age-, sex-, and community-matched subjects served as controls. RESULTS: Plasma total cholesterol (5.99 vs 5.45 mmol/L [232 vs 211 mg/dL], P=.003), low-density lipoprotein cholesterol (3.96 vs 3.45 mmol/L [153 vs 133 mg/dL], P=.004), and serum triglyceride (2.09 vs 1.82 mmol/L [8] vs 70 mg/dL], P=.03) levels were significantly higher among the patients with atherothrombotic strokes and transient ischemic attacks than among the control subjects. The inverse was true for high-density lipoprotein cholesterol (1.07 vs 1.18 mmol/L [41 vs 46 mg/dL], P=.02) levels. No significant differences were found in lipoprotein(a) levels or in the distribution of apolipoprotein E phenotypes or allele frequency. Serum ferritin levels did not differ significantly between patients and control subjects. CONCLUSIONS: Elevated low-density lipoprotein cholesterol and triglyceride levels are significant independent risk factors in patients with proven atherothrombotic cerebrovascular disease manifesting as stroke or transient ischemic attack. The level of stored serum iron, as reflected by serum ferritin levels, does not correlate with the presence of atherothrombotic cerebrovascular or coronary disease.

Protection of islets of Langerhans from antibodies by microencapsulation with alginate-poly-L-lysine membranes.

Microencapsulation of islets has been proposed to prevent their immune destruction following transplantation. An indirect immunofluorescence technique has been developed and used to study the permeability of the alginate-poly-L-lysine microcapsules to antibodies. Wistar rat islets were incubated with the R2D6 monoclonal mouse IgM antibody against rat islets, microencapsulated, and incubated with fluorescein-labeled goat IgG antibodies against mouse IgG and IgM. For the negative controls, the first antibody was omitted or both antibodies were omitted. The positive controls included islets incubated with both antibodies before they were encapsulated. Our study demonstrated that the alginate-poly-L-lysine membranes are not permeable to IgG when poly-L-lysine of molecular weights ranging from 21,000 to 390,000 are used. This simple immunofluorescence technique demonstrated the nonpermeability of the microcapsules to IgG, and could be useful for the initial evaluation of new types of membranes.

Method for the quantification of alginate in microcapsules.

Alginate is a key reagent in the preparation of microcapsules for cell transplantation. To address the question of the intracapsular alginate concentration, a sensitive assay has been developed to quantify the alginate content of microcapsules. The method is based on the metachromatic change induced by alginate binding to the dye, 1,9-dimethyl methylene blue (DMMB). The assay has a high sensitivity and precision. It covers a wide concentration range enabling the measurement of alginate in dilute supernatants as well as in microcapsules. For the latter, the membrane is initially dissolved by incubating the microcapsules in an alkaline medium. The effect of potentially interfering substances (poly-L-lysine (PLL), citrate, chloride, sodium) and of pH has been studied. Poly-L-lysine interfered with the assay at pH 6.5 but not at pH 13. Interference by sodium augmented with increasing sodium concentration and reached a plateau at 200 mM. This problem was overcome by routinely adjusting all samples to 500 mM sodium. The other substances tested had a negligible effect on the assay. The reliable measurement of alginate with this new assay will allow the optimization of the intracapsular alginate concentration.

Randomized, controlled trial of amitriptyline versus placebo for adolescents with "treatment-resistant" major depression.

OBJECTIVE: To assess the response to a serotonergic/noradrenergic tricyclic antidepressant, amitriptyline (AMI), in a group of adolescents with treatment-resistant major depressive disorder (MDD). METHOD: Twenty-seven depressed adolescents admitted to a state hospital underwent a 10-week randomized, controlled trial with a flexible dose of AMI or placebo. RESULTS: There were no differences between patients taking AMI (n = 13) and placebo (n = 14). Both treatment groups showed approximately 70% to 80% improvement on the clinical outcome measurements, and 65% to 70% showed functional improvement. At the end of the protocol, 30% of patients still fulfilled criteria for MDD and had impaired functioning. Patients taking AMI experienced significantly more dry mouth and tachycardia. The final AMI dose was 173.1 mg/day +/- 56.3 mg/day; blood levels were 226.2 ng/mL +/- 80.8 ng/mL. CONCLUSIONS: No significant differences were found between AMI and placebo, in part because of the high placebo response rate. Although both treatment groups showed substantial response, at the end of treatment a substantial proportion of patients still had MDD of subsyndromal symptoms of depression. This and other studies of tricyclic antidepressants question the use of this medication as first-line treatment for youths with MDD.

Alzheimer's disease: preliminary study of spatial distribution at birth place.

Alzheimer's disease (AD) is a neurodegenerative disorder which is characterized by a progressive loss of memory and the alteration of cognitive functions. At least three chromosomal segments have been associated with early-onset AD in genetic linkage studies. These results argue for a certain degree of heterogeneity in the genetic origin of some forms of AD, although environmental risk factors cannot be ruled out in late-onset AD. In this preliminary study, we analyzed the geographical distribution of the birth places of a sample of 235 AD cases born in a defined region of Quebec (Canada), between 1895 and 1935. We wished to test the hypothesis that risk factors acting at, or around birth place and time play a role in the etiology of AD. The field of study was divided into rural and urban areas. A reference population of live births was used to compute a measure of odds ratio (OR). The OR results showed a statistically significant excess of AD cases in the rural area as compared to the reference population. When stratified for sex, the OR results showed a global excess of female AD cases in both the rural and the urban areas. For men, only the urban area presented a statistically significant deficit. We also analyzed the structures of the genealogical kinships of the rural and urban sub-groups. Although AD cases from the rural sub-group were more closely related to each other than those from the urban one, removal of the kin pairs from the OR analysis seemed to have little effect on the rural/urban distribution of cases. Therefore, the OR results would not appear to be due primarily to a difference in the kinship structures of the two sub-groups. This could mean that some risk factors for AD afflict women more strongly than men, the effect being different depending on the urban or rural origin. However, potential biases such as a higher rate of report for women, differential migration between birth places or a differential mortality ratio between sexes could produce spurious results in the direction of what we have observed in this preliminary study.

Temporal intermittent rhythmic delta activity (TIRDA) in the diagnosis of complex partial epilepsy: sensitivity, specificity and predictive value.

Temporal interictal rhythmic delta activity or TIRDA was found in 45 of the 127 recordings of patients with complex partial epilepsy (CPE) referred for both awake and sleep EEG. TIRDA was more abundant during drowsiness and light sleep; it occurred more characteristically as trains of 50-100 microv sinusoidal or saw-toothed 1-4Hz activity, recorded predominantly from anterior temporal regions. When occurring bilaterally and independently, TIRDA varied from side to side. TIRDA is often found in association with anterior temporal spikes or sharp waves (TS) particularly during sleep, as observed in 43 out of 45 EEGs. TIRDA can nevertheless occur as an isolated abnormality, as noted in two sleep and 12 awake study recordings. Because of its high specificity and positive predictive value over a large range of prevalence, TIRDA should be singled out as an accurate interictal indicator of CPE. In patients with isolated TIRDA, the cost of prolonged EEG recording during sleep for the purpose of activating TS has to be weighed against the yield of eventually confirming the obvious.

[Factors of successful breast feeding in New Brunswick: information and compatible working conditions]. / Facteurs de réussite de l'allaitement maternel au Nouveau-Brunswick: information et conditions de travail compatibles.

Although breastmilk is the best food source for the first six months of life, breastfeeding rates at three and six months of age in New Brunswick are quite low. To determine action priorities to increase the duration of breastfeeding, we tried to identify its most important determining factors. Data were obtained from the 431 breastfeeding mothers in a representative sample of 777 infants born after a normal pregnancy. The mother's knowledge about breastfeeding is the most valuable factor that explains breastfeeding duration, followed by the compatibility of the mother's employment with breastfeeding. Interventions directed at improving either of these two factors should be encouraged particularly among mothers of lower socioeconomic status who breastfeed for shorter periods of time.

Who breastfeeds in New Brunswick, when and why?

We studied infant feeding in a representative sample of primiparous mothers of six-month-old infants in New Brunswick in 1982-83. At birth, 56% of infants were breastfed, decreasing to 31% at three months and 16% at six months; fewer were breastfed, and this for shorter periods of time, among the French population, those of lower socio-economic status or younger mothers. Most of the mothers who did not breastfeed did not attend prenatal classes and almost half had decided before their pregnancy to breastfeed or not. Most mothers breastfed because they felt their milk was better. Bottlefeeding mothers were mainly motivated by its convenience.