Shape matters: Near-field fluid mechanics dominate the collective motions of ellipsoidal squirmers

Microswimmers show a variety of collective motions. Despite extensive study, questions remain regarding the role of near-field fluid mechanics in collective motion. In this paper, we describe precisely the Stokes flow around hydrodynamically interacting ellipsoidal squirmers in a monolayer suspension. The results showed that various collective motions, such as ordering, aggregation, and whirls, are dominated by the swimming mode and the aspect ratio. The collective motions are mainly induced by near-field fluid mechanics, despite Stokes flow propagation over a long range. These results emphasize the importance of particle shape in collective motion.

Ablation of the p16(INK4a) tumour suppressor reverses ageing phenotypes of klotho mice

The p16^INK4a tumour suppressor has an established role in the implementation of cellular senescence in stem/progenitor cells, which is thought to contribute to organismal ageing. However, since p16^INK4a knockout mice die prematurely from cancer, whether p16^INK4a reduces longevity remains unclear. Here we show that, in mutant mice homozygous for a hypomorphic allele of the α-klotho ageing-suppressor gene (kl^kl/kl), accelerated ageing phenotypes are rescued by p16^INK4a ablation. Surprisingly, this is due to the restoration of α-klotho expression in kl^kl/kl mice and does not occur when p16^INK4a is ablated in α-klotho knockout mice (kl^−/−), suggesting that p16^INK4a is an upstream regulator of α-klotho expression. Indeed, p16^INK4a represses α-klotho promoter activity by blocking the functions of E2Fs. These results, together with the observation that the expression levels of p16^INK4a are inversely correlated with those of α-klotho throughout ageing, indicate that p16^INK4a plays a previously unrecognized role in downregulating α-klotho expression during ageing.

The protein p16^INK4a promotes senescence in tissue stem cells and thereby contributes to organismal ageing. Here the authors reveal that p16^INK4a also downregulates expression of a-klotho, thereby revealing an additional ageing-promoting function of 16^INK4a that is independent from its role in senescence.

Therapeutic trial of hematological disorders with intermittent administration of high-dose 1-alpha-hydroxyvitamin D3

Aplastic anemia and myelodysplastic syndrome were successfully treated with an intermittent administration of high-dose 1 alpha-hydroxy-vitamin D3, an active analogue of 1,25-dihydroxyvitamin D3. This effect was considered to be through the differentiation-inducing and immunomodulatory actions of 1,25-dihydroxyvitamin D3. The only adverse effect was hypercalciuria which was controllable by decreasing the dose.

Physiology of salivary secretion

The aim of the present work was to explain the mechanism of the acinar secretion of the salivary gland during stimulation. The following items were discussed and concluded. (1) The acinus is the majority of cells being the powerful transport system of the fluid from interstitial side to lumen. (2) Osmotic flow was clarified being a cause of water transport, in which the osmolality gradient across the acinus epithelium was initiated by a preceded salt transport. (3) The grades of osmotic gradient, of hydraulic conductivity, and of semipermeable property of gland epithelia were described. (4) On salt transport during stimulation, Na+ inflow across the basal plasma membrane and Na+ extrusion across the luminal membrane of the acinus cell were discussed with respect to the electrochemical gradient and ionic flow. From the electrophysiological work and the ionic distribution of the salivary gland, it is concluded that massive Na+ inflow and K+ outflow across the basal plasma membrane was a passive process due to an increase of permeability to those ion during stimulation, but the process of Na+ extrusion across the plasma membranes of the luminal side of the cell as well as of the secretory granules was active. (5) The electrochemical gradient for Na+ and K+ at the basal plasma membrane which had an important role for passive Na+ and K+ transport may be maintained by ouabain-sensitive Na+-K+ pump as most other cells. (6) A model for salt transport across the acinar cell was proposed. Intracellular Na+ due to passive Na+ inflow may activate cooperatively the Na(Cl) transport system at luminal plasma membrane and membrane of secretory granules in high levels of (Na+)in. Though it also activated the Na+ -K+ transport at the basal plasma membrane in any level of (Na+)in. (7) Energetics for the ion transport of gland was discussed with a transport-work rate equation as well as oxygen consumption in secretory state. It is assumed that the energy in active transport at the luminal plasma membrane requires more than the dissipated energy in passive process at the basal plasma membrane. The energy for active transport across the luminal plasma membrane may be corresponded to a main part of oxygen consumption for ion transport across the overall epithelium. (8) The phenomena of osmotic flow coupling with salt flow and of passive ionic flow coupling with electrochemical gradient which is maintained by Na+ -K+ pump may be an expression of production and utilization of negative entropy which is a characteristic of biological membrane.

Living situations associated with poor dietary intake among healthy Japanese elderly: the Ohasama Study

BACKGROUND

Rapid increases in life expectancy have led to concurrent increases in the number of elderly people living alone or those forced to change living situations. Previous studies have found that poor dietary intake was common in elderly people living alone. However, there have been few studies about the dietary intake in elderly people living in other situations, particularly those living with family other than a spouse (nonspouse family), which is common in Japan.

OBJECTIVE

To examine the differences in dietary intake by different living situations in elderly Japanese people. We analyzed the data of 1542 healthy residents in the town of Ohasama aged 60 years and over who had completed self-administered questionnaires.

METHODS

The dietary intake was measured using a validated 141-item food frequency questionnaire. Multiple regression models with robust (White-corrected) standard errors were individually fitted for nutrients and foods by living situation.

RESULTS

In men, although the presence of other family was correlated with significantly lower intake of protein-related foods, e.g., legumes, fish and shellfish, and dairy products, these declines were more serious in men living with nonspouse family. Conversely, in men living alone the intake of fruits and vegetables was significantly lower. In women, lower intakes of fruit and protein-related foods were significantly more common in participants living with nonspouse family than those living with only a spouse.

CONCLUSION

These findings revealed that elderly people living alone as well as those living with family other than a spouse had poor dietary intake, suggesting that strategies to improve food choices and skills for food preparation could promote of healthy eating in elderly Japanese people.

The real impact of telaprevir dosage on the antiviral and side effects of telaprevir, pegylated interferon and ribavirin therapy for chronic hepatitis C patients with HCV genotype 1

Triple therapy with telaprevir, pegylated interferon and ribavirin has been reported to improve antiviral efficacy but have potentially severe adverse effects in patients with chronic hepatitis C. To avoid the severe effects of telaprevir, lowering the dose has been suggested. However, impact of dosage changes on antiviral and adverse effects remains unclear. One hundred and sixty-six Japanese patients with HCV genotype 1 were treated with triple therapy. The drug exposure of each medication was calculated by averaging the dose actually taken. The overall SVR rate was 82%. The telaprevir discontinuation rate was 26%. The factors associated with discontinuation were an older age (≥65 y.o.) and a higher average dose during treatment. The telaprevir discontinuation rates were 42%, 25% and 14% in patients at ≥35, 25-35 and <25 mg/kg/day of telaprevir and 58% in older patients at ≥35 mg/kg/day of TVR. The factors associated with SVR were treatment-naïve, relapse to previous treatment, higher average telaprevir dose during treatment and completion of treatment. The SVR rate was higher, at 91%, in patients at 25-35 mg/kg/day of telaprevir than the 71% and 78% observed in those at <25 and ≥35 mg/kg/day of drug. In Japanese patients, a mean telaprevir dose of 25-35 mg/kg/day during treatment can augment its efficacy in triple therapy for patients with HCV genotype 1.

[Calcified amorphous tumor of the right atrium after open heart surgery; report of a case]

A 37-year-old woman, who had undergone surgery of atrial septal defect (ASD) at 12-year-old, developed bradycardia and referred to our hospital. Transthoracic echocardiography revealed high echoic tumor in the right atrium. The image of the tumor was of low intensity by T2 weighted magnetic resonance imaging (MRI) and floating mass with a stalk to the right atrium in cine MRI. She underwent tumor resection under cardiopulmonary bypass. Histopathologilal examination of the tumor was calcified amorphous tumor. The postoperative course was uneventful.

Retrospective study of changes in the sensitivity of the oral mucosa: sagittal split ramus osteotomy (SSRO) versus intraoral vertical ramus osteotomy (IVRO)

We investigated changes in the sensitivity of cutaneous points and the oral mucosa after sagittal split ramus osteotomy (SSRO) and assessed the differences between SSRO and intraoral vertical ramus osteotomy (IVRO). The subjects included in this study were 46 patients with mandibular prognathism who underwent IVRO (88 rami) and 30 patients who underwent SSRO (59 rami). An objective evaluation of the neurosensory status of each patient was completed preoperatively and at 1, 4, 8, 12, and 24 weeks postoperatively. Other variables studied for each patient included sex, age, magnitude of mandibular setback, and amount of blood loss during surgery. We found that a neurosensory recovery occurred earlier in the oral mucosa than at cutaneous points. The number of oral mucosa points showing reduced neurosensory function and neurosensory disturbance after SSRO was significantly higher than after IVRO at 1, 4, and 8 weeks (P<0.05). The nerve recovery observed after SSRO was delayed for a longer period than that noted in our previous study of IVRO. In conclusion, we found changes in sensitivity at cutaneous points and the oral mucosa after SSRO and assessed the differences between SSRO and IVRO.

Lateral migration of a spherical capsule near a plane wall in Stokes flow

Lateral migration is the motion of a particle perpendicular to the direction of the surrounding flow. One of the factors leading to the lateral migration of a deformable particle in Stokes flow is the presence of a nearby wall. We numerically investigate the lateral migration of a capsule in a near-wall simple shear flow using a boundary integral method coupled with a finite element method. We find that asymmetrical deformation of the capsule induced by the wall is correlated with a reduction in the lift velocity relative to the lift velocity predicted by a far-field analytical solution. A combination of this asymmetrical deformation, which decreases the lift velocity, and an increase in the value of the capsule stresslet near the wall, which works to increase the lift velocity, leads to a migration velocity that is nearly independent of capillary number and membrane constitutive law at large deformation near the wall.

Risk factors for hepatocellular carcinoma in hepatitis C patients with normal alanine aminotransferase treated with pegylated interferon and ribavirin

Pegylated interferon (Peg-IFN) plus ribavirin combination therapy is effective in patients with hepatitis C virus (HCV) infection and normal alanine aminotransferase levels (NALT). However, it remains unclear whether the risk of hepatocellular carcinoma (HCC) incidence is actually reduced in virological responders. In this study, HCC incidence was examined for 809 patients with NALT (ALT ≤ 40 IU/mL) treated with Peg-IFN alpha-2b and ribavirin for a mean observation period of 36.2 ± 16.5 months. The risk factors for HCC incidence were analysed by Kaplan-Meier method and Cox proportional hazards model. On multivariate analysis among NALT patients, the risk of HCC incidence was significantly reduced in patients with sustained virological response (SVR) or relapse compared with those showing nonresponse (NR) (SVR vs NR, hazard ratio (HR): 0.16, P = 0.009, relapse vs NR, HR: 0.11, P = 0.037). Other risk factors were older age (≥65 years vs <60 years, HR: 6.0, P = 0.032, 60-64 vs <60 years, HR: 3.2, P = 0.212) and male gender (HR: 3.9, P = 0.031). Among 176 patients with PNALT (ALT ≤ 30 IU/mL), only one patient developed HCC and no significant risk factors associated with HCC development were found. In conclusion, antiviral therapy for NALT patients with HCV infection can lower the HCC incidence in responders, particularly for aged and male patients. The indication of antiviral therapy for PNALT (ALT ≤ 30 IU/mL) patients should be carefully determined.

Crosstalk between the Rb pathway and AKT signaling forms a quiescence-senescence switch

Cell-cycle arrest in quiescence and senescence is largely orchestrated by the retinoblastoma (Rb) tumor-suppressor pathway, but the mechanisms underlying the quiescence-senescence switch remain unclear. Here, we show that the crosstalk between the Rb-AKT-signaling pathways forms this switch by controlling the overlapping functions of FoxO3a and FoxM1 transcription factors in cultured fibroblasts. In the absence of mitogenic signals, although FoxM1 expression is repressed by the Rb pathway, FoxO3a prevents reactive oxygen species (ROS) production by maintaining SOD2 expression, leading to quiescence. However, if the Rb pathway is activated in the presence of mitogenic signals, FoxO3a is also inactivated by AKT, thus reducing SOD2 expression and consequently allowing ROS production. This situation elicits senescence through irreparable DNA damage. We demonstrate that this pathway operates in mouse liver, indicating that this machinery may contribute more broadly to tissue homeostasis in vivo.