The Circadian System Contributes to Apnea Lengthening across the Night in Obstructive Sleep Apnea

STUDY OBJECTIVE

To test the hypothesis that respiratory event duration exhibits an endogenous circadian rhythm.

DESIGN

Within-subject and between-subjects.

SETTINGS

Inpatient intensive physiologic monitoring unit at the Brigham and Women's Hospital.

PARTICIPANTS

Seven subjects with moderate/severe sleep apnea and four controls, age 48 (SD = 12) years, 7 males.

INTERVENTIONS

Subjects completed a 5-day inpatient protocol in dim light. Polysomnography was recorded during an initial control 8-h night scheduled at the usual sleep time, then through 10 recurrent cycles of 2 h 40 min sleep and 2 h 40 min wake evenly distributed across all circadian phases, and finally during another 8-h control sleep period.

MEASUREMENTS AND RESULTS

Event durations, desaturations, and apnea-hypopnea index for each sleep opportunity were assessed according to circadian phase (derived from salivary melatonin), time into sleep, and sleep stage. Average respiratory event durations in NREM sleep significantly lengthened across both control nights (21.9 to 28.2 sec and 23.7 to 30.2 sec, respectively). During the circadian protocol, event duration in NREM increased across the circadian phases that corresponded to the usual sleep period, accounting for > 50% of the increase across normal 8-h control nights. AHI and desaturations were also rhythmic: AHI was highest in the biological day while desaturations were greatest in the biological night.

CONCLUSIONS

The endogenous circadian system plays an important role in the prolongation of respiratory events across the night, and might provide a novel therapeutic target for modulating sleep apnea.

Impairment of host resistance to helminthes with age in murine small intestine

Age-associated alterations of Th2 immune responses against nematode parasites are largely unknown. We investigated primary and memory responses against two types of gastrointestinal nematode parasites, Heligmosomoides polygyrus (Hp) and Nippostrongylus brasiliensis (Nb), in aged mice. The small intestinal gene expression of Th2 cytokines was almost unchanged after primary (Nb and Hp) and secondary infection (Hp) in aged mice in contrast to strongly increased small intestinal gene expression of Th2 cytokines in young (3-month-old) mice. Mucus production decreased (Nb), and worm expulsion was impaired (Nb and Hp) compared with the young mice. Immunofluorescent staining revealed that after Hp infection, the number of alternatively activated macrophages, which are induced by Th2 cytokines, was lower in the aged mice. On the other hand, the number of CD4(+) T cells recruited to the worm cysts was normal compared with the young mice. These results suggest that migration of CD4(+) T cells to the host-parasite interface is not affected by ageing. Alterations in Th2 immune responses in aged mice might be due to inappropriate or insufficient activation of CD4(+) T cells in the submucosa.

Preparation of polybenzoxazole nanofibers by a downsizing process

Poly(p-phenylene benzobisoxazole) (PBO) nanofibers were prepared from commercially available PBO fiber by a simple downsizing process for the first time.

Evaluation of nanodispersion of iron oxides using various polymers

In order to create Fe2O3 and Fe2O3·H2O nanoparticles, various polymers were used as dispersing agents, and the resulting effects on the dispersibility and nanoparticulation of the iron oxides were evaluated. It was revealed that not only the solution viscosity but also the molecular length of the polymers and the surface tension of the particles affected the dispersibility of Fe2O3 and Fe2O3·H2O particles. Using the dispersing agents 7.5% hydroxypropylcellulose-SSL, 6.0% Pharmacoat 603, 5.0% and 6.5% Pharmacoat 904 and 7.0% Metolose SM-4, Fe2O3 nanoparticles were successfully fabricated by wet milling using Ultra Apex Mill. Fe2O3·H2O nanoparticles could also be produced using 5.0% hydroxypropylcellulose-SSL and 4.0 and 7.0% Pharmacoat 904. The index for dispersibility developed in this study appears to be an effective indicator of success in fabricating nanoparticles of iron oxides by wet milling using Ultra Apex Mill.

Facile preparation of aramid nanofibers from Twaron fibers by a downsizing process

We introduce a simple preparation procedure for aramid nanofibers from Twaron fibers by using a downsizing process.

Immunocytochemical study of parvalbumin, calbindin D-28k, and calretinin in the superficial dorsal horn of the rat spinal cord following unilateral hindpaw inflammation

The effect of noxious stimulation on the immunore-activity of the calcium-binding proteins parvalbumin (PV), calbindin-D-28k (CB) and calretinin (CR) was investigated in the superficial dorsal horn of lumbar levels L5-L3 of the rat spinal cord. Freund's adjuvant was injected unilaterally into the hindpaw to induce inflammation. Immunohistochemical techniques were utilized to investigate changes in the calcium-binding proteins 2h and 1, 2, 4, and 7 days after injection. At 24h after injection, a decrease in the intensity of fluorescence of PV-immunoreactive (IR) fibers was observed in the superficial layer (substantia gelatinosa) of the ipsilateral dorsal horn (L5-L3) in most animals. Comparatively fewer animals exhibited changes in the CB- and CR-IR fibers, except at the L3 level 2 days after, and at the L4 level 7 days after the hindpaw injection. After the peak response, at 24h in most animals, there was a decline in the number of responders at 2 days and no differences were noted at 4 days. However, at 7 days, there was again an increase in the number of animals revealing diminished fluorescence intensity in the ipsilateral substantia gelatinosa. Changes in immunoreactivity of calcium binding proteins in the interneurons of the superficial lumbar dorsal horn may reflect hyperactivity within these neurons following noxious stimulation.

Delaying embryo development by storing at 4°C for synchronization to recipients in microinjection technique in rabbits

Short-term storage of embryos at low temperature induces developmental arrest of the embryo and would appear to be a valuable aid in embryo-transfer techniques to avoid wasting embryos. Embryo storage at 4°C was examined to allow synchronization with embryo-transfer recipients using the microinjection technique. Superovulation was induced in female Japanese White donor rabbits four days before mating with males. At the same time, control recipients were injected with human chorionic gonadotropin (hCG) to allow synchronization (R1); the hCG injections were delayed by 24 h in the experimental group (R2). DNA constructs for expressing human C-reactive protein or apolipoprotein AII were microinjected into the male pronuclei of the ova. The microinjected embryos were immediately transferred to recipients (R1) or stored at 4°C in phosphate-buffered saline containing 10% fetal bovine serum. After 17-20 h, the stored embryos were incubated at 37°C for one hour, and the morphologically normal embryos were transferred to recipients (R2). In the R1 rabbits, 855 embryos were transferred to 29 recipients, and 72.4% of the recipients became pregnant. Seven of the 84 offspring were transgenic. In the R2 rabbits, 478 embryos were transferred to 16 recipients, and 62.5% of the recipients became pregnant. Two of the 39 offspring were transgenic. There were no differences in pregnancy rate, litter size and transgenic integration rate between R1 and R2. These results suggest that the short-term 4°C storage of microinjected embryos can be a valuable method for synchronization with recipients, and reducing wastage of embryos and the sacrifice of rabbits.

Dental abnormalities in Schimke immuno-osseous dysplasia

Described for the first time in 1971, Schimke immuno-osseous dysplasia (SIOD) is an autosomal-recessive multisystem disorder that is caused by bi-allelic mutations of SMARCAL1, which encodes a DNA annealing helicase. To define better the dental anomalies of SIOD, we reviewed the records from SIOD patients with identified bi-allelic SMARCAL1 mutations, and we found that 66.0% had microdontia, hypodontia, or malformed deciduous and permanent molars. Immunohistochemical analyses showed expression of SMARCAL1 in all developing teeth, raising the possibility that the malformations are cell-autonomous consequences of SMARCAL1 deficiency. We also found that stimulation of cultured skin fibroblasts from SIOD patients with the tooth morphogens WNT3A, BMP4, and TGFβ1 identified altered transcriptional responses, raising the hypothesis that the dental malformations arise in part from altered responses to developmental morphogens. To the best of our knowledge, this is the first systematic study of the dental anomalies associated with SIOD.

Design of the polarization multi-pass Thomson scattering system

A novel configuration of the multi-pass Thomson scattering (TS) system is proposed to improve the time resolution and accuracy of electron temperature measurements by use of a polarization control technique. This configuration can realize a perfect coaxial multi-passing at each pass, and the number of round trips is not limited by the optical configuration. To confirm the feasibility of the new method, we installed this system in the GAMMA 10 plasma system. As a result, the integrated scattering signal of the double-pass configuration is about two times larger than that of the single-pass configuration. These results are in good agreement with the design.

Development of polarization-controlled multi-pass Thomson scattering system in the GAMMA 10 tandem mirror

In the GAMMA 10 tandem mirror, the typical electron density is comparable to that of the peripheral plasma of torus-type fusion devices. Therefore, an effective method to increase Thomson scattering (TS) signals is required in order to improve signal quality. In GAMMA 10, the yttrium-aluminum-garnet (YAG)-TS system comprises a laser, incident optics, light collection optics, signal detection electronics, and a data recording system. We have been developing a multi-pass TS method for a polarization-based system based on the GAMMA 10 YAG TS. To evaluate the effectiveness of the polarization-based configuration, the multi-pass system was installed in the GAMMA 10 YAG-TS system, which is capable of double-pass scattering. We carried out a Rayleigh scattering experiment and applied this double-pass scattering system to the GAMMA 10 plasma. The integrated scattering signal was made about twice as large by the double-pass system.