Typical and atypical smooth muscle cells (TSMCs and ASMCs, respectively) and interstitial cells (ICs) within the pacemaker region of the mouse renal pelvis were examined using focused ion beam scanning electron (FIB SEM) tomography, immunohistochemistry and Ca imaging. Individual cells within 500-900 electron micrograph stacks were volume rendered and associations with their neighbours established. 'Ribbon-shaped', Ano1 Cl channel immuno-reactive ICs were present in the adventitia and the sub-urothelial space adjacent to the TSMC layer. ICs in the proximal renal pelvis were immuno-reactive to antibodies for Ca3.1 and hyperpolarization-activated cation nucleotide-gated isoform 3 (HCN3) channel sub-units, while basal-epithelial cells (BECs) were intensely immuno-reactive to Kv7.5 channel antibodies. Adventitial to the TSMC layer, ASMCs formed close appositions with TSMCs and ICs. The T-type Cachannel blocker, Ni (10-200 μM), reduced the frequency while the L-type Ca channel blocker (1 μM nifedipine) reduced the amplitude of propagating Ca waves and contractions in the TSMC layer. Upon complete suppression of Ca entry through TSMC Ca channels, ASMCs displayed high-frequency (6 min) Ca transients, and ICs distributed into two populations of cells firing at 1 and 3 min, respectively. IC Ca transients periodically (every 3-5 min) summed into bursts which doubled the frequency of ASMC Ca transient firing. Synchronized IC bursting and the acceleration of ASMC firing were inhibited upon blockade of HCN channels with ZD7288 or cell-to-cell coupling with carbenoxolone. While ASMCs appear to be the primary pacemaker driving pyeloureteric peristalsis, it was concluded that sub-urothelial HCN3(+), Ca3.1(+) ICs can accelerate ASMC Ca signalling.

When exposed to sublethal high temperatures, budding yeast cells can survive for a period of time; however, a sufficient amount of ubiquitin is necessary for this survival. To understand the nature of the stress, we examined the morphological changes in yeast cells, focusing on the vacuoles. Changes in vacuolar morphology were notable, and ruffled vacuolar membranes, accelerated invaginations of vacuolar membranes, and vesicle-like formations were observed. These changes occurred in the absence of Atg1, Atg9 or Ivy1 but appeared to require endosomal sorting proteins, such as Vps23, Vps24 or Pep12. Furthermore, the serial sections of the vacuoles analysed using an electron microscopic analysis revealed that spherical invaginated structures were linked together in a vacuole. Because degradation of cell surface proteins is induced from heat stress, fusion of endosomal and vacuolar membranes might occur frequently in heat-stressed cells, and yeast cells might be able to cope with a rapid increase in vacuolar surface area by such invaginations.

This study aimed to leverage computer vision (CV) technology to develop a technique for quantifying postural control. A conventional quantitative index, occupational therapists’ qualitative clinical evaluations, and CV-based quantitative indices using an image analysis algorithm were applied to evaluate the postural control of 34 typically developed preschoolers. The effectiveness of the CV-based indices was investigated relative to current methods to explore the clinical applicability of the proposed method. The capacity of the CV-based indices to reflect therapists’ qualitative evaluations was confirmed. Furthermore, compared to the conventional quantitative index, the CV-based indices provided more detailed quantitative information with lower costs. CV-based evaluations enable therapists to quantify details of motor performance that are currently observed qualitatively. The development of such precise quantification methods will improve the science and practice of occupational therapy and allow therapists to perform to their full potential.

Polydimethylsiloxane (PDMS) is a commonly used silicone elastomer with broad applications. Particularly for bioengineering use, PDMS is treated with oxygen plasma with which its surface is oxidized to allow positive interaction with water and live cells. In exchange for the acquisition of hydrophilicity, the oxidized PDMS becomes mechanically brittle so that resulting formation of cracks affects the system in various ways. However, tensile strength (TS), which is an inherent capacity of a material to withstand tensile loads before breaking and is thus a key parameter limiting the use of the material, remains unclear regarding oxidized PDMS. Here we determine the TS of oxide layers created on the surface of PDMS based on micro-stretch experiments using a custom-made device. We show that the surface layer displays cracks upon tensile loading of small strains of within 10% to have a TS of ~10–100 kPa, which is approximately two orders of magnitude lower than that of unmodified PDMS. We further show that the TS sharply decreases with oxidation duration to become highly brittle, while the thickness of the resulting oxide layer finally reaches a plateau even with prolonged plasma treatment. Consequently, we suggest that gradual surface modification of PDMS takes place only within a finite region even with prolonged plasma treatment, as distinct from previously held assumptions. These quantitative data provide critical design information for the oxide layer of plasma-hydrophilized PDMS.

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