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Biomedical subjects

M Beaumont

Publications and source records attributed to M Beaumont.

At least 19 recordsLinked to original sources
PubMed2003

Caffeine or melatonin effects on sleep and sleepiness after rapid eastward transmeridian travel.

We measured the effects of slow-release caffeine (SRC) and melatonin (Mlt) on sleep and daytime sleepiness after a seven-time zone eastbound flight. In a double-blind, randomized, placebo-controlled study, each of three groups of nine subjects was given either 300 mg SRC on recovery day 1 (D1) to D5 (0800) or 5 mg Mlt on preflight D-1 (1700), flight day D0 (1600), and from D1 to D3 (2300), or placebo (Pbo) at the same times. Nighttime sleep was evaluated by polysomnography and daytime sleepiness from measurements of sleep latencies and continuous wrist actigraphy. Compared with baseline, we found a significant rebound of slow-wave sleep on night 1 (N1) to N2 under Pbo and Mlt and a significant decrease in rapid eye movement sleep on N1 (Pbo) and N1-N3 (Mlt). Sleepiness was objectively increased under Pbo (D1-D6) and Mlt (D1-D3). SRC reduced sleepiness but also tended to affect sleep quality until the last drug day. In conclusion, both drugs have positive effects on some jet lag symptoms after an eastbound flight: SRC on daytime sleepiness, and Mlt on sleep.

Adult↗
PubMed2003

Therapy-related acute promyelocytic leukemia.

PURPOSE: To analyze patient cases of therapy-related acute promyelocytic leukemia (tAPL), occurring after chemotherapy (CT), radiotherapy (RT) or both for a prior disorder, diagnosed during the last 20 years in three European countries. PATIENTS AND METHODS: The primary disorder and its treatment, interval from primary disorder to tAPL, characteristics of tAPL, and its outcome were analyzed in 106 patients. RESULTS: Eighty of the 106 cases of tAPL were diagnosed during the last 10 years, indicating an increasing incidence of tAPL. Primary disorders were predominantly breast carcinoma (60 patients), non-Hodgkin's lymphoma (15 patients), and other solid tumors (25 patients). Thirty patients had received CT alone, 27 patients had received RT alone, and 49 patients had received both. CT included at least one alkylating agent in 68 patients and at least one topoisomerase II inhibitor in 61 patients, including anthracyclines (30 patients), mitoxantrone (28 patients), and epipodophyllotoxins (19 patients). Median interval from primary disorder to tAPL diagnosis was 25 months (range, 4 to 276 months). Characteristics of tAPL were generally similar to those of de novo APL. With treatment using anthracycline-cytarabine-based CT or all-trans-retinoic acid combined with CT, actuarial survival was 59% at 8 years. CONCLUSION: tAPL is not exceptional, and develops usually less than 3 years after a primary neoplasm (especially breast carcinoma) treated in particular with topoisomerase II-targeted drugs (anthracyclines or mitoxantrone and less often etoposide). Characteristics and outcome of tAPL seem similar to those of de novo APL.

Adult↗
PubMed2003

The knowledge of healthcare professionals with regard to the treatment and prevention of head lice.

This study examined the knowledge and practice of healthcare professionals regarding the prevention and treatment of head lice 18 months after dissemination of local guidelines. A self-administered postal questionnaire was sent to all primary healthcare professionals (general practitioners and practice nurses), community healthcare professionals (community paediatricians, health visitors and school nurses) and pharmacists in South Staffordshire health district, UK. The overall response rate was 48% (range 24-63%). Compared to other groups: community healthcare professionals were more likely to refer to the guidelines and have adequate knowledge of treatment and prevention; pharmacists were least likely to refer to the guidelines; and primary healthcare professionals were most likely to have poor knowledge about prevention and treatment. Overall, healthcare professionals' knowledge regarding prevention methods was significantly better than their knowledge of treatment methods (63% vs. 5%, P <0.00001). In conclusion, the results of this study suggest that healthcare professionals' knowledge of control methods for head lice varies widely and is sub-optimal and may contribute to ineffective head lice control.

Adult↗
PubMed2002

Flavouring composition prepared by fermentation with Bacillus spp.

Fermented foodstuffs and condiments remain a key constituents of diets throughout many parts of Asia and Africa. In cases where the process of fermentation evolved for the development of taste or aroma, it often resulted in enhanced nutrition, stabilisation of the original raw materials, and detoxification of anti-nutrient factors. Several fermented products rely on the participation of various Bacillus species, including Bacillus natto and B. subtilis. Often, the finished products are of a very local character and exhibit sensory properties resulting from unique flora and processing technologies applied in small scale, home-based fermentations. Fermentation with B. natto and B. subtilis can produce very characteristic aromas in fermented products such as natto and dawadawa (also referred to as daddawa). Moreover, the hydrolytic capabilities of these microorganisms can result in a precursor-rich environment, which is useful for subsequent reactions leading to flavour production. A 1995 patented process demonstrated the ability to produce a fermented flavouring composition with the use of Bacillus spp. Hydrolysed protein obtained after fermentation with Bacillus spp. is mixed with reactive flavour precursors, which are subsequently heated to induce flavour formation and can be dried to a powder format. The product of this patented process imparts a basic meaty flavour, with a reduced yet characteristic dawadawa-like aroma. This paper briefly summarises some of the characteristics and uses of traditional dawadawa and illustrates alternatives described in the patent for the production of a process flavour base. Issues and considerations for the industrialisation of a fermentation process are briefly discussed, as well as some future opportunities for development and exploitation of traditional fermentation technology.

Bacillus↗
PubMed2001

Resynchronization of hormonal rhythms after an eastbound flight in humans: effects of slow-release caffeine and melatonin.

The aim of this work was to investigate the potential chronobiotic properties of slow-release caffeine, in comparison with melatonin, on resynchronization of endogenous melatonin and cortisol secretions after an eastbound flight by jet incurring a time loss of 7 h. A group of 27 reservists of the US Air Force received either slow-release caffeine (300 mg), melatonin (5 mg) or placebo before, during and/or after the transmeridian flight. Saliva and urine were sampled before the flight in the United States (from day -2 to day 0) and after the flight in France (from day 1 to day 10). Saliva was collected once a day on waking to determine saliva melatonin and cortisol concentrations. In addition, concentrations of caffeine in saliva were determined three times a day and of 6-sulphatoxymelatonin in urine collected overnight to check that the treatment regimes had been complied with. From day 3 to day 5, post-flight saliva melatonin concentrations were significantly different from control values in the placebo group only. During treatment with melatonin, the mean urinary 6-sulphatoxymelatonin concentration in the melatonin group was more than twice as high as in the two other groups. In the slow-release caffeine group and the melatonin group, mean saliva cortisol concentrations were significantly lower than control from day 2 to day 5, whereas the placebo group had a mean saliva cortisol concentration significantly lower than the control value from day 2 to day 9. In conclusion, these results indicate that administration of slow-release caffeine, as well as of melatonin, allows a faster resynchronization of hormone rhythms during the 4 days following an eastbound flight incurring the loss of 7 h.

Adjuvants, Immunologic↗
PubMed2001

A report of an outbreak of Shigellosis in a primary school in Staffordshire.

This paper describes the management of an outbreak of Shigellosis, reported in the national media, in a village school in Staffordshire. The issues encountered by the outbreak team during the management of this incident have re-affirmed the need for public and environmental health departments to work closely with educational bodies to develop clear and consistent action plans for the management of communicable disease outbreaks. The management of communicable disease in schools, the workplace and other settings should be addressed, possibly as a component of local health improvement plans.

Child↗
PubMed2001

Slow release caffeine and prolonged (64-h) continuous wakefulness: effects on vigilance and cognitive performance.

Some long work or shift work schedules necessitate an elevated and prolonged level of vigilance and performance but often result in sleep deprivation (SD), fatigue and sleepiness, which may impair efficiency. This study investigated the effects of a slow-release caffeine [(SRC) at the daily dose of 600 mg] on vigilance and cognitive performance during a 64 h continuous wakefulness period. Sixteen healthy males volunteered for this double-blind, randomised, placebo controlled, two-way crossover study. A total of 300-mg SRC or placebo (PBO) was given twice a day at 21:00 and 9:00 h during the SD period. Vigilance was objectively assessed with continuous electroencephalogram (EEG), the multiple sleep latency tests (MSLT) and wrist actigraphy. Cognitive functions (information processing and working memory), selective and divided attention were determined with computerised tests from the AGARD-NATO STRES Battery (Standardised Tests for Research with Environmental Stressors). Attention was also assessed with a symbol cancellation task and a Stroop's test; alertness was appreciated from visual analogue scales (VAS). Tests were performed at the hypo (02:00-04:00 h, 14:00-16:00 h) and hypervigilance (10:00-12:00 h, 22:00-00:00 h) periods during SD. Central temperature was continuously measured and safety of treatment was assessed from repeated clinical examinations. Compared with PBO, MSLT showed that SRC subjects were more vigilant from the onset (P=0.001) to the end of SD (P < 0.0001) whereas some cognitive functions were improved till the thirty third of SD but others were ameliorated through all the SD period and alertness was better from the thirteenth hour of SD, as shown by Stroop's test (P=0.048). We showed that 300-mg SRC given twice daily during a 64-h SD is able to antagonize the impairment produced on vigilance and cognitive functions.

Adult↗
PubMed2001

Genetic diversity and introgression in the Scottish wildcat.

This paper describes a genetic analysis of wild-living cats in Scotland. Samples from 230 wild-living Scottish cats (including 13 museum skins) and 74 house cats from England and Scotland were surveyed for nine microsatellite loci. Pelage characteristics of the wild-living cats were recorded, and the cats were then grouped into five separate categories depending on the degree to which they conformed to the characteristics attributed to Felis silvestris Schreber, 1775. Allele frequency differences between the morphological groups are greater than those among the three house cat samples. Analysis of genetic distances suggests that more of the differences between individuals can be explained by pelage than geographical proximity, and that pelage and geographical location are not confounded. Ordination of the genetic distances suggests two main groups of wild-living cats, with intermediates, and one group is genetically very similar to the house cats, while the other group contains all cats taxonomically identified as wildcat based on morphology. A genetic mixture analysis gives similar results to the ordination, but also suggests that the genotypes of a substantial number of cats in the wildcat group are drawn from a gene pool with genotypes in approximately equilibrium proportions. We argue that this is evidence that these cats do not have very recent domestic ancestry. However, from the morphological data it is highly likely that this gene pool also contains a contribution from earlier introgression of domestic cat genes.

Animals↗
PubMed2001

Genetic identification of wild and domestic cats (Felis silvestris) and their hybrids using Bayesian clustering methods.

Crossbreeding with free-ranging domestic cats is supposed to threaten the genetic integrity of wildcat populations in Europe, although the diagnostic markers to identify "pure" or "admixed" wildcats have never been clearly defined. Here we use mitochondrial (mt) DNA sequences and allelic variation at 12 microsatellite loci to genotype 128 wild and domestic cats sampled in Italy which were preclassified into three separate groups: European wildcats (Felis silvestris silvestris), Sardinian wildcats (Felis silvestris libyca), and domestic cats (Felis silvestris catus), according to their coat color patterns, collection localities, and other phenotypical traits, independently of any genetic information. For comparison, we included some captive-reared hybrids of European wild and domestic cats. Genetic variability was significantly partitioned among the three groups (mtDNA estimate of F(ST) = 0.36; microsatellite estimate of R(ST) = 0.30; P < 0.001), suggesting that morphological diversity reflects the existence of distinct gene pools. Multivariate ordination of individual genotypes and clustering of interindividual genetic distances also showed evidence of distinct cat groups, partially congruent with the morphological classification. Cluster analysis, however, did not enable hybrid cats to be identified from genetic information alone, nor were all individuals assigned to their populations. In contrast, a Bayesian admixture analysis simultaneously assigned the European wildcats, the Sardinian wildcats, and the domestic cats to different clusters, independent of any prior information, and pointed out the admixed gene composition of the hybrids, which were assigned to more than one cluster. Only one putative Sardinian wildcat was assigned to the domestic cat cluster, and one presumed European wildcat showed mixed (hybrid) ancestry in the domestic cat gene pool. Mitochondrial DNA sequences indicated that three additional presumed European wildcats might have hybrid ancestry. These four cats were sampled from the same area in the northernmost edge of the European wildcat distribution in the Italian Apennines. Admixture analyses suggest that wild and domestic cats in Italy are distinct, reproductively isolated gene pools and that introgression of domestic alleles into the wild-living population is very limited and geographically localized.

Alleles↗
PubMed1999

Positive pressure generation by pneumatic and electronic O2 regulators: a bench experimental evaluation.

BACKGROUND: The introduction of advanced anti-G protection into agile fast fighter aircraft may result in the regular use of positive pressure breathing (PPB) for G protection by aircrew. Since PPB results in an external additional work of breathing (WoB), we compared the mechanical performance of the pneumatic and electronic O2 regulators designed for "Mirage 2000" and "Rafale" aircraft. HYPOTHESIS: Since mask pressure is regulated by the electronic device in relation to flow, mask pressure will remain constant throughout the respiratory cycle, so that PPB-related additional WoB will be less with the electronic regulator. METHODS: In a bench dynamic study performed with a sinusoidal pump, we measured variations in mask pressure (deltaP) and calculated WoB at 0, 3 and 6 kPa of PPB (0, 30 and 60 cm H2O, respectively), for 0.5, 1 and 2 L of volume and for 10, 15 and 20 cycles per minute of respiratory rate. RESULTS: We found that, compared with the pneumatic device, inspiratory and expiratory WoB with the electronic device were respectively lower by approximately 25% (p < 0.05) and by approximately 10% (NS) at 3 and 6 kPa of PPB, for all respiratory conditions. Nevertheless, we also observed remaining variations in mask pressure with the electronic regulator, due to complex impedance of the inspiratory circuit, since the device uses the pressure measured into the regulator. CONCLUSIONS: We concluded that the electronic control of mask pressure is relatively efficient but that the device would be improved by placing the site of the pressure measurement into the mask.

Aerospace Medicine↗
PubMed1998

Microsatellites reveal heterosis in red deer.

The fitness consequences of inbreeding and outbreeding are poorly understood in natural populations. We explore two microsatellite-based variables, individual heterozygosity (likely to correlate with recent inbreeding) and a new individual-specific internal distance measure, mean d2 (focusing on events deeper in the pedigree), in relation to two measures of fitness expressed early in life, birth weight and neonatal survival, in 670 red deer calves (Cervus elaphus) born on the Isle of Rum between 1982 and 1996. For comparison, we also analyse inbreeding coefficients derived from pedigrees in which paternity was inferred by molecular methods. Only 14 out of 231 calves (6.1%) had non-zero inbreeding coefficients, and neither inbreeding coefficient nor individual heterozygosity was consistently related to birth weight or neonatal survival. However, mean d2 was consistently related to both fitness measures. Low mean d2 was associated with low birth weight, especially following cold Aprils, in which foetal growth is reduced. Low mean d2 was also associated with low neonatal survival, but this effect was probably mediated by birth weight because fitting birth weight to the neonatal survival model displaced mean d2 as an explanatory variable. We conclude that in the deer population fitness measures expressed early in life do not show evidence of inbreeding depression, but they do show evidence of heterosis, possibly as a result of population mixing. We also demonstrate the practical problems of estimating inbreeding via pedigrees compared with a direct marker-based estimate of individual heterozygosity. We suggest that, together, individual heterozygosity and mean d2, estimated using microsatellites, are useful tools for exploring inbreeding and outbreeding in natural population.

Age Factors↗
PubMed1998

Genetic and environmental factors affecting bone mineral density in large families.

This study assessed whether relatives with low bone mineral density (BMD) could be identified in five large families using historical, biochemical, and genetic markers for osteoporosis. Fifty of 65 relatives had their bone density and bone turnover markers measured, together with an assessment of their risk factors for osteoporosis. Only 33% (5/15) of siblings, 50% (6/12) of children and 43% (10/23) of nephews and nieces had entirely normal BMD. There was no difference in life-style risk factors for osteoporosis, history of previous fractures or body mass index between normal subjects and those with osteopenia or osteoporosis. Osteopenic individuals had a significantly higher than normal osteocalcin value. Within families, there was no clear association between BMD and any of the genetic markers (vitamin D receptor gene polymorphisms, COL 1A1 and COL 1A2 polymorphisms of the collagen gene), either alone or in combination. The addition of genetic markers to the other risk factors for low BMD did not improve the prediction of BMD. In conclusion, we suggest that the presence of osteoporosis in a first degree relative should be one of the clinical indications for bone density measurement as the individuals at risk would not be picked up by other methods.

Adult↗
PubMed1998

Gravity effects on upper airway area and lung volumes during parabolic flight.

We measured upper airway caliber and lung volumes in six normal subjects in the sitting and supine positions during 20-s periods in normogravity, hypergravity [1.8 + head-to-foot acceleration (Gz)], and microgravity ( approximately 0 Gz) induced by parabolic flights. Airway caliber and lung volumes were inferred by the acoustic reflection method and inductance plethysmography, respectively. In subjects in the sitting position, an increase in gravity from 0 to 1. 8 +Gz was associated with increases in the calibers of the retrobasitongue and palatopharyngeal regions (+20 and +30%, respectively) and with a concomitant 0.5-liter increase in end-expiratory lung volume (functional residual capacity, FRC). In subjects in the supine position, no changes in the areas of these regions were observed, despite significant decreases in FRC from microgravity to normogravity (-0.6 liter) and from microgravity to hypergravity (-0.5 liter). Laryngeal narrowing also occurred in both positions (about -15%) when gravity increased from 0 to 1.8 +Gz. We concluded that variation in lung volume is insufficient to explain all upper airway caliber variation but that direct gravity effects on tissues surrounding the upper airway should be taken into account.

Adult↗
PubMed1997

Effects of chest wall counterpressures on lung mechanics under high levels of CPAP in humans.

We assessed the respective effects of thoracic (TCP) and abdominal/lower limb (ACP) counterpressures on end-expiratory volume (EEV) and respiratory muscle activity in humans breathing at 40 cmH2O of continuous positive airway pressure (CPAP). Expiratory activity was evaluated on the basis of the inspiratory drop in gastric pressure (DeltaPga) from its maximal end-expiratory level, whereas inspiratory activity was evaluated on the basis of the transdiaphragmatic pressure-time product (PTPdi). CPAP induced hyperventilation (+320%) and only a 28% increase in EEV because of a high level of expiratory activity (DeltaPga = 24 +/- 5 cmH2O), contrasting with a reduction in PTPdi from 17 +/- 2 to 9 +/- 7 cmH2O . s-1 . cycle-1 during 0 and 40 cmH2O of CPAP, respectively. When ACP, TCP, or both were added, hyperventilation decreased and PTPdi increased (19 +/- 5, 21 +/- 5, and 35 +/- 7 cmH2O . s-1 . cycle-1, respectively), whereas DeltaPga decreased (19 +/- 6, 9 +/- 4, and 2 +/- 2 cmH2O, respectively). We concluded that during high-level CPAP, TCP and ACP limit lung hyperinflation and expiratory muscle activity and restore diaphragmatic activity.

Adult↗
PubMed1997

[Russian intra vehicular space suit and cold protection].

During space flights, astronauts use equipment allowing protection against many environmental factors. During tests realised in Russia, space suit efficiency was evaluated particularly concerning cold protection capacity in cold water (3 degrees C) and in cold air (-30 degrees C). Obtained results prove that this equipment allows to prevent hypothermia in cold water and ensure thermal comfort in cold air.

Cold Temperature↗
PubMed1996

Effect of zolpidem on sleep and ventilatory patterns at simulated altitude of 4,000 meters.

The purpose of this study was to assess the effect of zolpidem 1 0 mg, a new imidazopyridine hypnotic drug, on sleep and respiratory patterns at a simulated altitude of 4,000 meters. Eight male subjects spent three nights in a decompression chamber. The first study night was spent at the ambient pressure corresponding to sea level. The two other nights were spent at a simulated altitude of 4,000 meters with either zolpidem or a placebo in random order according to a double-blind, crossover design. All subjects showed periodic breathing (PB) during sleep at simulated high altitude. Furthermore, altitude was associated with decreases in total sleep time (TST), slow-wave sleep (SWS), and REM sleep, and with significant increases in Stage 1 duration and in the arousal index. Most arousals were synchronous with the hyperpneic phase of PB. The main finding of our study is that zolpidem improved sleep characteristics at high altitude, inducing a decrease in sleep onset latency (placebo, 22 +/- 12 min versus zolpidem, 10 +/- 6 min), an increase in SWS duration (placebo, 46 +/- 28 min versus zolpidem, 69 +/- 28 min), and a reduction in the arousal index during SWS (placebo, 7.4 +/- 4.1 per h versus zolpidem: 2.4 +/- 1.0 per h). Furthermore, none of the respiratory parameters were significantly affected by zolpidem in any sleep stage. In conclusion, zolpidem improved sleep quality at high altitude without adversely affecting respiration.

Adult↗
PubMed1995

Plasma ammonia concentration in brown trout in soft acidic water and its relationship to decreased swimming performance

Adult brown trout (300&shy;600 g) were acclimated for 2 weeks to an artificial soft water (Ca2+, 50 &micro;mol l-1) and maintained at either 5 &deg;C (October to March) or 15 &deg;C (May to August). Following insertion of a cannula into the dorsal aorta under MS-222 anaesthesia and a recovery period of 2 days, the fish were exposed to a 4 day episode of sub-lethal copper levels at pH 5 or kept at control conditions of pH 7 without copper. The copper concentrations had been predetermined by toxicity testing and were approximately 0.47 &micro;mol l-1 at 5 &deg;C and 0.08 &micro;mol l-1 at 15 &deg;C. At 5 &deg;C, a group of fish was also exposed to approximately 0.08 &micro;mol l-1 copper at pH 5. Plasma total ammonia (Tamm) concentration was significantly elevated by exposure to copper and pH 5. In resting trout exposed to the appropriate sub-lethal copper concentration at pH 5, Tamm was six and 7.5 times greater at 5 and 15 &deg;C, respectively, than those of control trout at the respective temperatures. Although unconfirmed, an elevation of ammonia production alone seems unlikely to account for such substantial increases. From previous studies, there is little evidence of impairment of respiratory gas exchange in trout exposed to these copper concentrations and yet, in the acidic test waters, the gradient of NH3 partial pressure between fish and water was 5.5&shy;6 times greater than that under control conditions. Swimming performance determined by the critical swimming speed (Ucrit) was reduced by copper and acid exposure, and a significant relationship existed between Ucrit and the plasma ammonia concentration of exercised trout. Ammonium ions influence several key enzymes involved in energy metabolism, and elevated ammonia levels might, therefore, reduce the capacity of muscle to exercise. Alternatively, ammonia may have affected the nervous coordination of exercise either centrally or by disrupting peripheral motor innervation.

Journal Article↗