A critical role of Ca2+/calmodulin-dependent protein kinase II in coupling between evening and morning circadian oscillators in the suprachiasmatic nucleus.

Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) is widely expressed in the brain and is involved in various functions, including memory formation, mood and sleep. We previously reported that CaMKIIα is involved in the circadian molecular clock. Mice lacking functional CaMKIIα (K42R mice) exhibited a gradual increase in activity time (α decompression) of running-wheel (RW) activity due to a lengthened circadian period (τ) of activity offset under constant darkness (DD). In the present study, to investigate the functional roles of CaMKIIα in behavioural rhythms, we measured RW and general movements simultaneously under prolonged DD. Tau became longer as the relative intensity of behaviour activity within an activity time shifted from activity onset towards activity offset. In some K42R mice, α was gradually expanded with a marked reduction of RW activity, while general movements persisted without noticeable decline, which was followed by an abrupt shortening of α (α compression) with differential phase shifts of the activity onset and offset and recovery of RW activity. These results suggest that an internal coupling between the oscillators controlling activity onset and offset is bidirectional but with different strengths. The α compression occurred recurrently in 38% of K42R mice examined with an average interval of 37 days in association with attenuation of RW activity but never in the wild-type (WT) mice. Consistent with behavioural rhythms, the circadian period of the PER2::LUC rhythm in the cultured suprachiasmatic nucleus (SCN) slice was significantly longer in K42R than in WT. These findings are best interpreted by assuming that a loss of functional CaMKIIα attenuates the coupling between the onset and offset oscillators.

Two oscillatory components detected by forced splitting of the sleep-wake cycle in humans.

The sleep-wake cycle of human subjects was artificially split into two episodes by imposing an 8-h light and 4-h dark cycle (LD 8:4) twice a day for 7 days, which was followed by a 3-day free-running session. Sleep was permitted only in the dark period. The subjects in the ordinary group were exposed to ordinary light (ca. 500 lx) in the 8-h light period, and those in the bright light group to bright (ca. 5,000 lx) and ordinary light alternatively with bright light after the first dark period (2400-400). Split sleeps persisted in the free-running session with the major episode around the first dark period and the minor episode around the second dark period. By contrast, circadian melatonin rhythm in the free-running session significantly phase delayed in the ordinary light group, but phase advanced in the bright light group, keeping the melatonin rhythm unsplit. The length of nocturnal melatonin secretion (NMS) was significantly shortened in the bright light group. Interestingly, the falling phase of NMS advanced significantly further than the rising phase. Such a difference was not detected in the ordinary light group. Similar differences were observed in the body temperature rhythm. These findings indicated oscillatory mechanisms underlying split sleeps distinct from the circadian pacemaker and suggested an involvement of different circadian oscillators in the rising and falling phases of NMS, which is consistent with the dual oscillator model proposed for the circadian system of nocturnal rodents.NEW & NOTEWORTHY The present study demonstrated that human sleep was separated into two essentially identical components, which persisted under constant conditions, suggesting circadian oscillator underlying split-sleep episodes. The study also indicated differential light sensitivities in the rising and falling phases of circadian melatonin rhythm, indicating the involvement of two different oscillators. These results consisted of the evening and morning dual-oscillator hypothesis for the circadian pacemaker and the hierarchical model for the pacemaker and sleep-wake cycle.

Comparison of limb outcomes between bypass surgery and endovascular therapy in dialysis-dependent and -independent patients with chronic limb-threatening ischemia.

OBJECTIVE: To examine limb salvage (LS) and wound healing in dialysis-dependent and -independent patients with chronic limb-threatening ischemia (CLTI) after infrainguinal bypass surgery or endovascular therapy (EVT). METHODS: We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) stage 2 to 4 between 2015 and 2020. The primary endpoint was LS. The secondary endpoint included wound healing, amputation-free survival (AFS), periprocedural complications, and 2-year survival. Comparison of these outcomes were made after propensity score matching. RESULTS: We analyzed 252 dialysis-dependent (318 limbs) and 305 dialysis-independent (354 limbs) patients. Propensity score matching extracted 202 pairs with no significant differences in characteristics. The LS rate in bypass surgery was better than that in EVT in dialysis-dependent patients (P < .001). There was no significant difference in the LS rates between bypass surgery and EVT in dialysis-independent patients (P = .168). The wound healing rate of bypass surgery was better than that of EVT both dialysis-dependent and -independent patients with CLTI. The AFS rate of bypass surgery was better than that of EVT in dialysis-dependent patients (P < .001). There was no significant difference in the AFS rates between bypass surgery and EVT in dialysis-independent patients (P = .099). There was no significant difference in the occurrence of Clavien-Dindo ≥ IV and V between bypass surgery and EVT in dialysis-dependent and -independent patients. Age ≥75 years, serum albumin levels <3.5 g/dL, and non-ambulatory status were risk factors for 2-year mortality in dialysis-dependent patients. The 2-year survival rates in dialysis-dependent patients with risk factors of 0, 1, 2, and 3 were 82.5%, 67.1%, 49.5%, and 10.2%, respectively (P < .001). CONCLUSIONS: For LS and wound healing, bypass surgery was preferred for revascularization in dialysis-dependent patients with WIfI stage 2 to 4. Although dialysis dependency was one of the risk factors for 2-year mortality, dialysis-dependent patients, who have 0 to 1 risk factors, may benefit from bypass surgery, as 2-year survival of >50% is expected.

Infra-inguinal bypass surgery vs endovascular revascularization for chronic limb-threatening ischemia in average- and high-risk patients.

OBJECTIVE: This study aimed to evaluate treatment outcomes after bypass surgery or endovascular therapy (EVT) in average- and high-risk patients with chronic limb-threatening ischemia (CLTI). METHODS: We retrospectively analyzed multicenter data of patients who underwent infra-inguinal revascularization for CLTI between 2015 and 2022. A high-risk patient was defined as one with estimated 30-day mortality rate ≥5% or 2-year survival rate ≤50%, as determined by the Surgical Reconstruction vs Peripheral Intervention in Patients With Critical Limb Ischemia (SPINACH) calculator. The amputation-free survival (AFS), limb salvage (LS), wound healing, and 30-day mortality were compared separately for the average- and high-risk patients between the bypass and EVT with propensity score matching. RESULTS: We analyzed 239 and 31 propensity score-matched pairs in the average- and high-risk patients with CLTI. In the average-risk patients, the 2-year AFS and LS rates were 78.1% and 94.4% in the bypass group and 63.0% and 87.7% in the EVT group (P < .001 and P = .007), respectively. The 1-year wound healing rates were 88.6% in the bypass group and 76.8% in the EVT group, respectively (P < .001). The 30-day mortality was 0.8% in the bypass surgery and 0.8% in the EVT group (P = .996). In the high-risk patients, there was no differences in the AFS, LS, and wound healing between the groups (P = .591, P = .148, and P = .074). The 30-day mortality was 3.2% in the bypass group and 3.2% in the EVT group (P = .991). CONCLUSIONS: Bypass surgery is superior to EVT with respect to the AFS, LS, and wound healing in the average-risk patients. EVT is a feasible first-line treatment strategy for high-risk patients with CLTI undergoing revascularization, based on the lack of significant differences in the 2-year AFS rate, between the bypass surgery and EVT cohorts.

Influence of inframalleolar modifier P0/P1 on wound healing in bypass surgery vs endovascular therapy in patients with chronic limb-threatening ischemia.

OBJECTIVE: This study aimed to compare the influence of inframalleolar (IM) P0/P1 on wound healing in bypass surgery vs endovascular therapy (EVT) in patients with chronic limb-threatening ischemia (CLTI). METHODS: We retrospectively analyzed the multicenter data of patients who underwent infra-inguinal revascularization for CLTI between 2015 and 2022. IM P represents target artery crossing into foot, with intact pedal arch (P0) and absent or severely diseased pedal arch (P1). The endpoints were wound healing, limb salvage (LS), and postoperative complications. RESULTS: We analyzed 66 and 189 propensity score-matched pairs in the IM P0 and IM P1 cohorts, respectively. In the IM P0 cohort, the 1-year wound healing rates were 94.5% and 85.7% in the bypass surgery and EVT groups, respectively (P = .092), whereas those in the IM P1 cohort were 86.2% and 66.2% in the bypass surgery and EVT groups, respectively (P < .001). In the IM P0 cohort, the 2-year LS rates were 96.7% and 94.1% in the bypass surgery and EVT groups, respectively (P = .625), and those in the IM P1 cohort were 91.8% and 81.5% in the bypass surgery and EVT groups, respectively (P = .004). No significant differences were observed between the bypass surgery and EVT in terms of postoperative complication rates in either the IM P0 or P1 cohorts. CONCLUSIONS: Bypass surgery facilitated better wound healing and LS than EVT in patients with IM P1. Conversely, no differences in wound healing or LS were observed between groups in patients with IM P0. Bypass surgery should be considered a better revascularization strategy than EVT in patients with tissue loss and IM P1 disease.

Validation of JCLIMB, SPINACH, and VQI Calculators for Prediction of Two Year Survival in Patients With Chronic Limb Threatening Ischaemia After Infra-Inguinal Surgical or Endovascular Revascularisation.

OBJECTIVE: This study aimed to evaluate three survival prediction models: the JAPAN Critical Limb Ischaemia Database (JCLIMB), Surgical Reconstruction Versus Peripheral Intervention in Patients With Critical Limb Ischaemia (SPINACH), and Vascular Quality Initiative (VQI) calculators. METHODS: Multicentre data of patients who underwent infrainguinal revascularisation for chronic limb threatening ischaemia between 2018 and 2021 were analysed retrospectively. The prediction models were validated using a calibration plot analysis with the intercept and slope. The discrimination was evaluated using area under the curve (AUC) analysis. The observed two year overall survival (OS) was evaluated by the Kaplan - Meier method. The two year OS predicted by each model at < 50%, 50 - 70%, and > 70% was defined as high, medium, and low risk, respectively. RESULTS: A total of 491 patients who underwent infra-inguinal revascularisation were analysed. The rates of surgical revascularisation, endovascular therapy, and hybrid therapy were 26.5%, 70.1%, and 5.5%, respectively. The average age was 75.6 years, and the percentages of patients with diabetes mellitus and dialysis dependent end stage renal disease were 66.6% and 44.6%, respectively. The tissue loss rate was 85.7%. The intercept and slope were -0.13 and 1.18 for the JCLIMB, 0.11 and 0.82 for the SPINACH, and -0.15 and 1.10 for the VQI. The AUC for the two year OS of JCLIMB, SPINACH, and VQI were 0.758, 0.756, and 0.740, respectively. The observed two year OS rates of low, medium, and high risk using the JCLIMB calculator were 80.1%, 61.1%, and 28.5%, respectively (p < .001), using the SPINACH calculator were 81.0%, 57.0%, and 38.1%, respectively (p < .001), and using the VQI calculator were 77.8%, 45.8%, and 49.6%, respectively (p < .001). CONCLUSION: The JCLIMB, SPINACH, and VQI survival calculation models were useful, although the OS predicted by the VQI model appeared to be lower than the observed OS.

Treatment Outcomes in Octogenarians with Chronic Limb-Threatening Ischemia after Infrainguinal Bypass Surgery or Endovascular Therapy.

BACKGROUND: This study aimed to analyze the clinical outcomes after revascularization for chronic limb-threatening ischemia (CLTI) in patients aged ≥ 80 years and < 80 years. METHODS: We retrospectively analyzed multicenter data of 789 patients who underwent infrainguinal revascularization for CLTI between 2015 and 2021. The end points were 2-year overall survival (OS), amputation-free survival (AFS), limb salvage (LS), and postoperative complications. RESULTS: A total of 90 patients aged ≥ 80 years and 200 patients aged < 80 years underwent bypass surgery (BSX), and 205 patients aged ≥ 80 years and 294 patients aged < 80 years underwent endovascular therapy (EVT). Before the propensity score matching, multivariate analyses showed that age ≥ 80 years, lower body mass index and serum albumin levels, nonambulatory status, and end-stage renal disease were independent risk factors for 2-year mortality in the BSX and EVT groups. After propensity score matching, the 2-year OS was better in the < 80 years cohort than in the ≥ 80 years cohort in both the BSX and EVT groups (P = 0.018 and P = 0.035, respectively). There was no difference in the 2-year LS rates between the < 80 years and the ≥ 80 years cohorts in both the BSX and EVT groups (P = 0.621 and P = 0.287, respectively). According to the number of risk factors, except for age ≥ 80 years, there was no difference in the 2-year AFS rates between the < 80 years and ≥ 80 years cohorts for the BSX and EVT groups with 0-1 risk factor (P = 0.957 and P = 0.655, respectively). However, the 2-year AFS rate was poor, especially in the ≥ 80 years cohort in the BSX with 2-4 risk factors (P = 0.015). The Clavien-Dindo ≥ IV complication rates tended to be higher in the ≥ 80 years cohort than in the < 80 years cohort only in the BSX with 2-4 risk factors (P = 0.056). CONCLUSIONS: Patients with CLTI aged ≥ 80 years had poorer OS than those aged < 80 years. However, there was no difference in LS between the ≥ 80 years and < 80 years cohorts in both the BSX and EVT groups. Although age ≥ 80 years was associated with poorer OS, patients with 0-1 risk factor may benefit from revascularization, including BSX, because no difference was observed in AFS or Clavien-Dindo ≥ IV complications.

Differential responses to artificial photoperiods of the rising and falling phases of human melatonin rhythm are consistent with a dual oscillator hypothesis.

Circadian rhythms and sleep-wake cycles were measured in volunteers staying singly in temporal isolation unit where they were exposed to artificial short and long light-dark (LD) cycles for 7 days. The long day consisted of 16-h light and 8-h dark (LD 16:8) and the short day consisted of 8-h light and 16-h dark (LD 8:16). During the light period, bright light of approximately 5,000 lux was given from the ceiling and during the dark period there was no illumination. Sleep was monitored by bed sensors, wrist actiwatch, and polysomnography (PSG) on the first and last nights of the schedule. Sleep length was significantly longer under LD 8:16 than under LD 16:8 and the sleep quality estimated by PSG was worse under LD 8:16 than under LD 16:8, which were comparable to natural seasonality in sleep. The circadian rhythm in plasma melatonin was measured in dim light (10 lux) before and after the LD exposures. The nocturnal melatonin secretion (NMS) was significantly longer after LD 8:16 than after LD 16:8 due to differential phase shifts of the rising and falling phases of NMS. After LD 8:16, the falling phase was much advanced than the rising phase, whereas after LD 16:8 the rising phase was much delayed than the falling phase, resulting in the NMS compression. These results indicate that the light sensitivity in terms of phase shifting is different in the two circadian phases, supporting a dual oscillator hypothesis with different phase-response curves for light in the human circadian system.NEW & NOTEWORTHY The present study demonstrated differential light responsiveness of the rising and falling phases of nocturnal melatonin secretion in human subjects exposed to artificial long (LD 16:8) and short days (LD 8:16) and suggested the involvement of different oscillators under these phases. The findings well mimicked the seasonality of the circadian rhythms in nature and consisted with the evening/morning dual oscillator hypothesis proposed originally for nocturnal rodents, providing a new concept for the human circadian system.

Treatment outcomes between bypass surgery and endovascular therapy in patients with chronic limb-threatening ischemia classified as bypass-preferred category based on Global Vascular Guidelines.

OBJECTIVE: The aim of this study was to examine outcomes between bypass surgery and endovascular therapy (EVT) in patients with chronic limb-threatening ischemia (CLTI), classified as bypass-preferred according to the Global Vascular Guidelines (GVG). METHODS: We retrospectively analyzed the multi-center data of patients who underwent infrainguinal revascularization for CLTI with Wound, Ischemia, and foot Infection (WIfI) Stage 3 to 4 and Global Limb Anatomical Staging System (GLASS) Stage III, which is classified as bypass-preferred category by the GVG between 2015 and 2020. The endpoints were limb salvage and wound healing. RESULTS: We analyzed 301 patients and 339 limbs following 156 bypass surgeries and 183 EVTs. The 2-year limb salvage rates were 92.2% in the bypass surgery group and 76.3% in the EVT group, respectively (P < .01). The 1-year wound healing rates were 86.7% in the bypass surgery group and 67.8% in the EVT group (P < .01). Multivariate analysis shows decreased serum albumin level (P < .01), increased wound grade (P = .04), and EVT (P < .01) were risk factors for major amputation. Decreased serum albumin level (P < .01), increased wound grade (P < .01), GLASS infrapopliteal grade (P = .02), inframalleolar (IM) P grade (P = .01), and EVT (P < .01) were risk factors for impaired wound healing. Subgroup analysis of limb salvage in patients after EVT, decreased serum albumin level (P < .01), increased wound grade (P = .03), increased IM P grade (P = .04), and congestive heart failure (P < .01) were risk factors for major amputation. According to scoring by existence of these risk factors, 2-year limb salvage rates following EVT were 83.0% and 42.8% for the total score of 0 to 2 and of 3 to 4, respectively (P < .01). CONCLUSIONS: Bypass surgery provides better limb salvage and wound healing in patients with WIfI Stage 3 to 4 and GLASS Stage III, which is classified as bypass-preferred category by the GVG. In patients after EVT, serum albumin level, wound grade, IM P grade, and congestive heart failure were related to major amputation. Although bypass surgery may be considered as initial revascularization procedure in patients classified as bypass-preferred category, in case that EVT has to be selected, relatively acceptable outcomes can be expected in patients with less of these risk factors.

Global Limb Anatomic Staging System Inframalleolar Modifier Predicts Limb Salvage and Wound Healing in Patients with Chronic Limb Threatening Ischaemia Undergoing Endovascular Infrainguinal Revascularisation.

OBJECTIVE: This study aimed to analyse the influence of the Global Anatomic Staging System (GLASS) and inframalleolar (IM) disease on the treatment outcomes of patients with chronic limb threatening ischaemia (CLTI) who undergo endovascular treatment (EVT) METHODS: Data of patients who underwent infrainguinal endovascular therapy (EVT) for CLTI between 2015 and 2019 at two centres were analysed retrospectively. The endpoints were major amputation, major adverse limb events (MALE), and wound healing. RESULTS: Overall, 276 patients and 340 limbs were analysed. The number of revascularisations for an infrapopliteal lesion was 48 (70.6%), 63 (63.0%), and 142 (82.6%) in the GLASS I, GLASS II, and GLASS III stages, respectively (p < .001). There was no statistically significant difference in limb salvage among the GLASS stages (p = .78). The limb salvage rates at one year were 94.6%, 88.0%, and 70.0% in the IM P0 P1, and P2 groups, respectively (p < .001). Multivariable analysis showed that Wound, Ischemia, and foot Infection (WIfI) stage, and IM grade were risk factors for major amputation. The freedom from MALE rates at two years were 60.5%, 45.3%, and 41.1% in the GLASS I, II, and III stages, respectively (p = .003) and 64.1%, 43.5%, and 18.4% in the IM P0, P1, and P2 groups, respectively (p < .001). Multivariable analysis demonstrated that WIfI stage, GLASS stage, IM grade, and infrapopliteal revascularisation were risk factors for MALE. There was no significant difference in wound healing among GLASS I - III (p = .75). The wound healing rates at 365 days were 78.6%, 68.6%, and 42.0% in the IM P0, P1, and P2 groups, respectively (p = .065). Multivariable analysis showed that WIfI stage and IM P2 were risk factors for incomplete wound healing. CONCLUSION: GLASS IM was associated with major amputation, MALE, and wound healing, while GLASS stage was associated with only MALE.

Risk Factors for Major Amputation in Chronic Limb-Threatening Ischemia Patients Classified as Wound, Ischemia, and Foot Infection Stage 4 following Infrainguinal Revascularization.

BACKGROUND: To evaluate limb salvage outcomes and risk factors for major amputation in chronic limb-threatening ischemia (CLTI) patients classified as stage 4 per the wound, ischemia, and foot infection (WIfI) classification following infrainguinal revascularization. METHODS: We retrospectively analyzed multicenter data of patients who had undergone infrainguinal revascularization for CLTI between 2015 and 2020. The endpoint was secondary major amputation defined as an above- or below-knee amputation following infrainguinal revascularization. RESULTS: We analyzed 243 patients with CLTI and 267 limbs. Bypass surgery was performed in 14 (25.5%) and 120 (56.6%) limbs from the secondary major amputation and limb salvage groups, respectively (P < 0.01). Endovascular therapy (EVT) was performed in 41 limbs (74.5%) in the secondary major amputation group and 92 limbs (43.4%) in the limb salvage group (P < 0.01). The average serum albumin levels were 3.0 ± 0.6 and 3.4 ± 0.5 g/dL in the secondary major amputation and limb salvage groups, respectively (P < 0.01). The percentage of congestive heart failure (CHF) was 36.4% and 14.2% in secondary major amputation and limb salvage groups, respectively (P < 0.01). The number of limbs with infra-malleolar (IM) P0, P1, and P2 were 4 (7.3%), 37 (67.3%), and 14 (25.5%), respectively, in the secondary major amputation group and 58 (27.4%), 140 (66.0%), and 14 (6.6%), respectively, in the limb salvage group (P < 0.01). Limb salvage rates at 1 year were 91.0% and 68.6% in the bypass and EVT groups, respectively (P < 0.01). Limb salvage rates at 1 year in patients with IM P0, P1, and P2 were 91.8%, 79.9%, and 53.1%, respectively (P < 0.01). Multivariate analysis revealed that serum albumin level [hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.36-0.89; P = 0.01], hypertension (HR, 0.39; 95% CI, 0.21-0.75; P < 0.01), CHF (HR, 2.10; 95% CI, 1.09-4.05; P = 0.03), wound grade (HR, 1.72; 95% CI, 1.03-2.88; P = 0.04), IM P (HR, 2.08; 95% CI, 1.27-3.42; P < 0.01), and EVT (HR, 3.31; 95% CI, 1.77-6.18; P < 0.01) as independent risk factors for secondary major amputation being required. CONCLUSIONS: Among CLTI patients with WIfI stage 4, the limb salvage rate was poor in those with IM P1-2 following infrainguinal EVT. Low serum albumin levels, CHF, high wound grade, IM P1-2, and EVT were independent risk factors for CLTI patients requiring major amputation.

Bypass Surgery Provides Better Outcomes Compared with Endovascular Therapy in Patients with Chronic Limb-Threatening Ischemia Classified as Indeterminate Category According to the Global Vascular Guidelines.

BACKGROUND: The present study aimed to determine the preferred initial revascularization procedure between bypass surgery and endovascular therapy (EVT) in patients with chronic limb-threatening ischemia (CLTI) categorized as indeterminate according to the Global Vascular Guidelines (GVG). METHODS: We retrospectively analyzed the multicenter data of patients who underwent infrainguinal revascularization for CLTI categorized as indeterminate according to the GVG between 2015 and 2020. The end point was the composite of relief from rest pain, wound healing, major amputation, reintervention, or death. RESULTS: A total of 255 patients with CLTI and 289 limbs were analyzed. Of the 289 limbs, 110 (38.1%) and 179 (61.9%) underwent bypass surgery and EVT, respectively. The 2-year event-free survival rates with respect to the composite end point were 63.4% and 28.7% in the bypass and EVT groups, respectively (P < 0.01). Multivariate analysis revealed that increased age (P = 0.03); decreased serum albumin level (P = 0.02); decreased body mass index (P = 0.02); dialysis-dependent end-stage renal disease (P < 0.01); increased Wound, Ischemia, and foot Infection (WIfI) stage (P < 0.01); Global Limb Anatomic Staging System (GLASS) III (P = 0.04); increased inframalleolar grade (P < 0.01); and EVT (P < 0.01) were independent risk factors for the composite end point. In the WIfI-GLASS 2-III and 4-II subgroups, bypass surgery was superior to EVT with regard to 2-year event-free survival (P < 0.01). CONCLUSIONS: Bypass surgery is superior to EVT in terms of the composite end point in patients classified as indeterminate according to the GVG. Bypass surgery should be considered an initial revascularization procedure, especially in the WIfI-GLASS 2-III and 4-II subgroups.

A fixed single meal in the subjective day prevents free-running of the human sleep-wake cycle but not of the circadian pacemaker under temporal isolation.

Effects of a fixed single meal per day were examined on the circadian pacemaker and sleep-wake cycle in subjects under temporal isolation. When the time of single meal was allowed to take at any time of day (ad-lib meal), the sleep-wake cycle as well as the circadian rhythms in plasma melatonin, cortisol, and core body temperature were significantly phase-delayed in 8 days. On the other hand, when the time of meal was fixed at 1800 h in local time (RF meal), the phase-shift of sleep-wake cycle was not significant while those of the circadian rhythms were significant. The differential effects of a fixed single meal schedule were confirmed in most individual subjects. There was no evidence for the prefeeding increase in plasma cortisol and leptin levels under the fixed single meal schedule. The plasma ghrelin level was apparently high before meal in both ad-lib and RF meal groups, which was, however, likely sculptured by a nonspecific prandial drop and gradual increase after meal intake. Single meal augmented the prandial increase of plasma insulin levels by four to five times. These findings indicate that a single meal at a fixed time of the day during the subjective day failed to prevent the human circadian pacemaker but prevented the sleep-wake cycle from free running for at least 8 days under temporal isolation, suggesting that mealtime was a potent nonphotic time cue for the human sleep-wake cycle.

Isolated giant true intercostal artery aneurysm with arteriovenous fistula: A case report.

OBJECTIVES: Intercostal artery aneurysm (IAA) is a very rare condition. Interestingly, only one study reported a case of intercostal aneurysm caused by an arteriovenous fistula (AVF). Here, we report the case of a patient with non-ruptured isolated giant true IAA caused by an AVF (size, 28 × 41 mm). METHODS: Treatment options for IAA include open surgery and endovascular treatment (EVT). We chose EVT, as it is minimally invasive. The right 11th intercostal artery and aneurysm diverged from the aorta. Two outflow arteries, one inflow artery, and an AVF from the aneurysm were confirmed, and coil embolization was performed. The artery of Adamkiewicz did not communicate with the right 11th intercostal artery. We performed angiography and confirmed occlusion of IAA with endoleak. RESULTS: There were no clinical findings indicative of spinal cord infarction after treatment. The patient did not develop complications and was discharged the day after treatment. Endoleak was not observed on computed tomography angiography findings at 1 month after treatment. CONCLUSIONS: In our patient, an AVF might have caused IAA. Endovascular treatment for non-ruptured isolated giant IAA is a safe and minimally-invasive treatment. We found that performing EVT is beneficial when the size of the IAA exceeds 30 mm.

CaMKII is essential for the cellular clock and coupling between morning and evening behavioral rhythms.

Daily behavioral rhythms in mammals are governed by the central circadian clock, located in the suprachiasmatic nucleus (SCN). The behavioral rhythms persist even in constant darkness, with a stable activity time due to coupling between two oscillators that determine the morning and evening activities. Accumulating evidence supports a prerequisite role for Ca(2+) in the robust oscillation of the SCN, yet the underlying molecular mechanism remains elusive. Here, we show that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) activity is essential for not only the cellular oscillation but also synchronization among oscillators in the SCN. A kinase-dead mutation in mouse CaMKIIα weakened the behavioral rhythmicity and elicited decoupling between the morning and evening activity rhythms, sometimes causing arrhythmicity. In the mutant SCN, the right and left nuclei showed uncoupled oscillations. Cellular and biochemical analyses revealed that Ca(2+)-calmodulin-CaMKII signaling contributes to activation of E-box-dependent gene expression through promoting dimerization of circadian locomotor output cycles kaput (CLOCK) and brain and muscle Arnt-like protein 1 (BMAL1). These results demonstrate a dual role of CaMKII as a component of cell-autonomous clockwork and as a synchronizer integrating circadian behavioral activities.

GABAergic mechanisms in the suprachiasmatic nucleus that influence circadian rhythm.

The mammalian central circadian clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN contains multiple circadian oscillators which synchronize with each other via several neurotransmitters. Importantly, an inhibitory neurotransmitter, γ-amino butyric acid (GABA), is expressed in almost all SCN neurons. In this review, we discuss how GABA influences circadian rhythms in the SCN. Excitatory and inhibitory effects of GABA may depend on intracellular Cl- concentration, in which several factors such as day-length, time of day, development, and region in the SCN may be involved. GABA also mediates oscillatory coupling of the circadian rhythms in the SCN. Recent genetic approaches reveal that GABA refines circadian output rhythms, but not circadian oscillations in the SCN. Since several efferent projections of the SCN have been suggested, GABA might work downstream of neuronal pathways from the SCN which regulate the temporal order of physiology and behavior.

Ultradian calcium rhythms in the paraventricular nucleus and subparaventricular zone in the hypothalamus.

The suprachiasmatic nucleus (SCN), the master circadian clock in mammals, sends major output signals to the subparaventricular zone (SPZ) and further to the paraventricular nucleus (PVN), the neural mechanism of which is largely unknown. In this study, the intracellular calcium levels were measured continuously in cultured hypothalamic slices containing the PVN, SPZ, and SCN. We detected ultradian calcium rhythms in both the SPZ-PVN and SCN regions with periods of 0.5-4.0 hours, the frequency of which depended on the local circadian rhythm in the SPZ-PVN region. The ultradian rhythms were synchronous in the entire SPZ-PVN region and a part of the SCN. Because the ultradian rhythms were not detected in the SCN-only slice, the origin of ultradian rhythm is the SPZ-PVN region. In association with an ultradian bout, a rapid increase of intracellular calcium in a millisecond order was detected, the frequency of which determined the amplitude of an ultradian bout. The synchronous ultradian rhythms were desynchronized and depressed by a sodium channel blocker tetrodotoxin, suggesting that a tetrodotoxin-sensitive network is involved in synchrony of the ultradian bouts. In contrast, the ultradian rhythm is abolished by glutamate receptor blockers, indicating the critical role of glutamatergic mechanism in ultradian rhythm generation, while a GABAA receptor blocker increased the frequency of ultradian rhythm and modified the circadian rhythm in the SCN. A GABAergic network may refine the circadian output signals. The present study provides a clue to unraveling the loci and network mechanisms of the ultradian rhythm.

Ileocolic arterial aneurysm associated with segmental arterial mediolysis: A case report.

OBJECTIVES: Segmental arterial mediolysis is a rare disease that most commonly affects the superior mesenteric artery among abdominal arteries. However, aneurysms involving the ileocolic arterial branch of the superior mesenteric artery are extremely rare. Here, we describe the treatment of a patient with an ileocolic arterial aneurysm suspected to have occurred secondary to segmental arterial mediolysis. METHODS: We confirmed the diagnosis of ileocolic arterial aneurysm, which showed the characteristic "string-of-beads" appearance of the distal main trunk of the superior mesenteric artery on angiography. We performed endovascular coil embolization for the aneurysm, and for both the inflow and outflow vessels. After confirming that the aneurysm was no longer visible, the treatment was completed. RESULTS: There were no clinical findings suspicious of ischemic enteritis or intestinal necrosis after embolization. We confirmed that the ileocolic arterial aneurysm was not observed on computed tomography angiography one month after treatment. CONCLUSIONS: While development of an ileocolic arterial aneurysm associated with segmental arterial mediolysis is very rare, it is at a high risk of sudden rupture. Therefore, coil embolization is a useful intervention in such patients and can be implemented based on the size and morphology of the aneurysm.

Weak coupling between intracellular feedback loops explains dissociation of clock gene dynamics.

Circadian rhythms are generated by interlocked transcriptional-translational negative feedback loops (TTFLs), the molecular process implemented within a cell. The contributions, weighting and balancing between the multiple feedback loops remain debated. Dissociated, free-running dynamics in the expression of distinct clock genes has been described in recent experimental studies that applied various perturbations such as slice preparations, light pulses, jet-lag, and culture medium exchange. In this paper, we provide evidence that this "presumably transient" dissociation of circadian gene expression oscillations may occur at the single-cell level. Conceptual and detailed mechanistic mathematical modeling suggests that such dissociation is due to a weak interaction between multiple feedback loops present within a single cell. The dissociable loops provide insights into underlying mechanisms and general design principles of the molecular circadian clock.

Synchronous circadian voltage rhythms with asynchronous calcium rhythms in the suprachiasmatic nucleus.

The suprachiasmatic nucleus (SCN), the master circadian clock, contains a network composed of multiple types of neurons which are thought to form a hierarchical and multioscillator system. The molecular clock machinery in SCN neurons drives membrane excitability and sends time cue signals to various brain regions and peripheral organs. However, how and at what time of the day these neurons transmit output signals remain largely unknown. Here, we successfully visualized circadian voltage rhythms optically for many days using a genetically encoded voltage sensor, ArcLightD. Unexpectedly, the voltage rhythms are synchronized across the entire SCN network of cultured slices, whereas simultaneously recorded Ca2+ rhythms are topologically specific to the dorsal and ventral regions. We further found that the temporal order of these two rhythms is cell-type specific: The Ca2+ rhythms phase-lead the voltage rhythms in AVP neurons but Ca2+ and voltage rhythms are nearly in phase in VIP neurons. We confirmed that circadian firing rhythms are also synchronous and are coupled with the voltage rhythms. These results indicate that SCN networks with asynchronous Ca2+ rhythms produce coherent voltage rhythms.