Chronotype delay and sleep disturbances shaped by the Antarctic polar night.

Chronotype is a reliable biomarker for studying the influence of external zeitgebers on circadian entrainment. Assessment of chronotype variation in participants exposed to extreme photoperiods may be useful to investigate how changes in light-dark cycle modulate the circadian system. This study aimed to examine chronotype and sleep changes during a winter campaign at the Argentine Antarctic station Belgrano II. A sample of 82 men who overwintered in Antarctica completed the Munich Chronotype Questionnaire during March (daylight length: 18.6 h), May (daylight length: 2.8 h), July (daylight length: 0 h), September (daylight length: 14.5 h), November (daylight length: 24 h). The main results showed a decrease in sleep duration and a delay in chronotype and social jetlag during the polar night, highlighting the influence of social cues and the impact of the lack of natural light on circadian rhythms.

How Sleep Research in Extreme Environments Can Inform the Military: Advocating for a Transactional Model of Sleep Adaptation.

PURPOSE OF REVIEW: We review the literature on sleep in extreme environments. Accordingly, we present a model that identifies the need for mitigating interventions to preserve sleep quality for military deployments. RECENT FINDINGS: Situational factors that affect sleep in extreme environments include cold temperatures, isolated and confined areas, fluctuating seasonality, photoperiodicity, and extreme latitudes and altitudes. Results vary across studies, but general effects include decreased total sleep time, poor sleep efficiency, and non-specific phase delays or phase advances in sleep onset and sleep architecture. Considering habitability measures (e.g., light or temperature control) and individual differences such as variable stress responses or sleep need can mitigate these effects to improve mood, cognition, and operational performance. Although the situational demands during military missions inevitably reduce total sleep time and sleep efficiency, mitigating factors can attenuate sleep-related impairments, hence allowing for optimal mission success and personnel safety.

Physical sleeping environment is related to insomnia risk and measures of readiness in US army special operations soldiers.

BACKGROUND: US military service members have characteristically poor sleep, even when 'in garrison' or at one's home base. The physical sleeping environment, which is often poor in military-provided housing or barracks, may contribute to poor sleep quality in soldiers. The current study aimed to assess whether the sleeping environment in garrison is related to sleep quality, insomnia risk and military readiness. METHODS: Seventy-four US army special operations soldiers participated in a cross-sectional study. Soldiers were queried on their sleeping surface comfort and the frequency of being awakened at night by excess light, abnormal temperatures and noise. Subjective sleep quality and insomnia symptoms were also queried, via the Pittsburgh Sleep Quality Index and Insomnia Severity Index, respectively. Lastly, measures of soldier readiness, including morale, motivation, fatigue, mood and bodily pain, were assessed. RESULTS: Soldiers reporting temperature-related and light-related awakenings had poorer sleep quality higher fatigue and higher bodily pain than soldiers without those disturbances. Lower ratings of sleeping surface comfort were associated with poorer sleep quality and lower motivation, lower morale, higher fatigue and higher bodily pain. Each 1-point increase in sleeping surface comfort decreased the risk for a positive insomnia screen by 38.3%, and the presence of temperature-related awakenings increased risk for a positive insomnia screen by 78.4%. Those living on base had a poorer sleeping environment than those living off base. CONCLUSION: Optimising the sleep environment-particularly in on-base, military-provided housing-may improve soldier sleep quality, and readiness metrics. Providers treating insomnia in soldiers should rule out environment-related sleep disturbances prior to beginning more resource-intensive treatment.

Italian Huntington disease patients--data and tissue bank.

We have collected clinical and genetic data on Huntington disease (HD) patients and their families over the last 5 years at the Unit of Neurogenetics, IRCCS Neuromed of Pozzilli (IS), Italy. Data on 854 mutation carriers are included in the data bank, together with a large number of DNA samples, blood, and other tissues. In particular, lymphoblastoid cell lines from 100 patients, including subjects carrying very rare genetic conditions (CAG mutation homozygosity, juvenile and infantile onset, pre-mutations) have been established. For all these initiatives ethical approval from the bioethics committee was obtained. We wish to extend this initiative to all families, investigators, and institutions within and, possibly outside, the Italian border in an attempt to enlarge the bank and to institute a HD Research Roster.

Hip fracture in nursing homes: an Italian study on prevalence, latency, risk factors, and impact on mobility.

Hip fracture may cause and/or complicate institutionalization. We undertook this study to define its overall prevalence among the residents of four nursing homes in Central Italy as well as its latency and impact on mobility when it occurred within institutions. We also performed a case control analysis with the aim of identifying potential risk factors for hip fracture in nursing home. Among the 211 residents (160 women, mean age 82.2 +/- 9.29 years, and 51 men, mean age 77.1 +/- 8.9 years), 42 were hip fracture cases, with a prevalence of almost 20%, and a female/male ratio of 6/1.23 fractures preceded institutionalization; of these 19 (17 females and 2 males) occurred within the nursing homes (mean age 83.2 +/- 6.3 years). The average interval between institutionalization and fracture was 74.2 months. The impact of hip fracture on mobility was relevant. The percentage of residents ambulating autonomously fell from 95% to 32% among those who had fractured. Fractured subjects were characterized by worse mobility and function than unfractured subjects, while comorbidity, cognitive functions, and use of psychotropic drugs were similar. Prefracture mobility of fractured subjects was better than that of age-and sex-matched residents who had never fractured their hip. Regarding hip fracture in our nursing home population we can conclude that (1) hip fracture is one of the main causes of institutionalization; (2) in most cases hip fracture occurred late in the course of the nursing home stay; (3) the functional impact of the fracture was relevant when it occurred in institutions. We also suggest that preserved mobility may represent an additional risk factor for hip fracture in nursing homes.

Impact of the earthquake of September 26, 1997 in Umbria, Italy on the socioenvironmental and psychophysical conditions of an elderly population.

The consequences of natural disasters on the social and health status of older people have not been deeply considered. The aim of this study was to evaluate the socioenvironmental and psychophysical conditions of an elderly population after a devastating earthquake. A randomly selected group of 332 older people (> or =64 years) was selected among 1548 eligible subjects living in the city of Nocera Umbra four months after an earthquake of 5.6 magnitude on the Richter scale. Three geriatricians evaluated the study subjects by means of a structured interview, and standardized scales, which considered physical and mental status, mood and anxiety, and self-perception of well-being, as well as the characteristics of family composition and social interactions. Of the study subjects, 11.1% lived alone, and 33.4% with the spouse only. Most were self-sufficient in the basic activities of daily life. Musculoskeletal diseases and hypertension were the most frequently observed pathologies in this geriatric population. In addition, 47.9% of the subjects lived in temporary houses; this group more frequently suffered from hypertension, and had a higher score of comorbidity as measured by Cumulative Illness Rating Scale (CIRS) compared to people who remained at home. People living in the pre-fabricated huts also showed a higher score on the Geriatric Depression Scale and the Hamilton scale for anxiety, and complained more often of their health status, evaluated as self-perception of well-being, when compared to the home dwellers. Although all the studied subjects suffered from the discomforts caused by the earthquake, the precariousness of living in temporary houses, whose structural characteristics do not take the needs of elderly subjects into account, could justify the higher distress experienced by persons housed in the huts. These observations suggest that, after natural disasters, emergency programs should be more adapted to elderly people, whose needs and expectations are often different from those of young adults.

Age-related cortical bone loss at the metacarpal.

In order to evaluate in vivo the entity of endosteal and periosteal changes with age in the two sexes, and their relative contribution to age-related cortical bone loss, we undertook a cross-sectional study on a population of normal Caucasian subjects. The group included 189 women and 107 men who were studied by photodensitometry and radiogrammetry of the second metacarpal bone, derived from the same standard hand X-ray. Of the subjects, 134 were 65 years of age or older (75 women and 59 men). Metacarpal bone mineral density (BMD) correlated with age in both sexes, with an annual bone loss rate of 0.5% in women and 0.15% in men. In the over 65 group, correlation was significant only in women, who underwent an acceleration in the rate of bone loss (1% per year). Marrow cavity width (M), cortical index at the second metacarpal shaft (MI) and external width (W) all correlated with age in both sexes, although generally better in the female than in the male sex. M almost doubled from the fourth to the ninth decade in women and increased 50% in men. In the same age interval, MI showed an annual decrease of 0.49% in females and 0.33% in males. In the over 65 group, cortical thinning rate was significant in women (0.39% per annum) but not in men (0.14% per annum), whereas correlation of W was not significant in either sex. Finally, MI correlated with BMD in the whole study population and in the over 65, with a female prevalence in correlation strength maintained throughout life. The following conclusions can be derived for metacarpal aging: (1) an acceleration in cortical bone loss occurs in females after age 65; (2) age-related growth in periosteal diameter, although significant in the whole population, is negligible in the elderly of both sexes; (3) age-related cortical bone loss is generally more dependent on cortical thinning in women than in men.

The effect of dental prophylaxis instruments on the surface roughness of metals used for metal ceramic crowns.

Prophylactic instruments may cause surface deterioration of metal crown margins, which could cause or aid the retention and accumulation of plaque. In this investigation, highly polished metal disks of high content gold (RX Y), low content gold (Aspen), silver palladium (RX 91), and nickel-chrome alloy (REX III) had their surfaces tracked with an explorer, hand scaler, curette, and a Dentsply Cavitron instrument. The surface roughness was measured with a profilometer. The results indicate that the high content gold was the least resistant to surface deterioration and the ultrasonic scaler caused the most surface deterioration to all the metals.

Cells of origin and topographic organization of corticospinal neurons in the guinea pig by the retrograde HRP method.

In the guinea pig, horseradish peroxidase (HRP) was injected in the cervical or lumbar enlargements of the spinal cord in order to examine the origin and topographical organization of corticospinal (CS) neurons. The cortex was divided into granular and agranular regions to attempt correlations with the location of labeled CS neurons. These, of all sizes, are found only in pyramidal layer V of both kinds of cortical regions and could be seen as single, grouped or organized in clusters of 3-5 or more cells. The soma diameters of HRP CS neurons ranged from 13 to 49 microns. The largest labeled cells were present in the medial part of both agranular and granular cortices and included the giant pyramidal neurons which were found only in the rostromedial agranular cortex. The predominating intermediate-size cells were mostly present in lateral granular areas. The smaller cells were distributed in rostrolateral agranular and caudal granular regions. Morphological evidence suggests that an aggregation in clusters of labeled neurons and the different groups of CS neurons identified in different cortical areas may have additional differences in organization with respect to their precise topographical relations and functional properties. Neurons projecting to cervical levels were more abundant compared to projecting to the lumbar spinal cord, being distributed widely more lateral and anterior on the hemisphere to cortical neurons projecting to lumbar enlargement. These were located only medially on the dorsal surface of the brain. The two groups of labeled neurons were distributed in both agranular and granular cortices and occur adjacent to each other with only a narrow strip of overlap. The findings i.e. laminar organization, the pyramidal shape of CS neurons of all sizes, the presence of clusters and the somatotopic distribution of CS neurons seen in the guinea pig are discussed in comparison with equivalent findings on the corticospinal tract (CST) system of other species. The presence of labeled neurons within the cortex on both sides following unilateral HRP injections in the spinal cord points to a bilateral origin of the CST. This finding is discussed on the basis of the present study and previous autoradiographic findings.

The distribution of descending brain stem projections to spinal cord in the guinea pig. A horseradish peroxidase study.

In the guinea pig brain stem neurons projecting to the spinal cord were identified by the horseradish peroxidase (HRP) method. Following lumbar injection labelled neurons were found in the RF, VL, R, MNV, TMNV, RTP, NR, PVG, LH and DMH. The distribution of HRP-positive neurons following cervical injection was roughly the same as that observed after lumbar injection except for the presence of labelled cells in the NSNV and their absence in the MNV and TMNV.