The HAL3-PPZ1 dependent regulation of nonsense suppression efficiency in yeast and its influence on manifestation of the yeast prion-like determinant [ISP(+)

The efficiency of stop codons read-through in yeast is controlled by multiple interactions of genetic and epigenetic factors. In this study, we demonstrate the participation of the Hal3-Ppz1 protein complex in regulation of read-through efficiency and manifestation of non-Mendelian anti-suppressor determinant [ISP(+)]. Over-expression of HAL3 in [ISP(+)] strain causes nonsense suppression, whereas its inactivation displays as anti-suppression of sup35 mutation in [isp(-)] strain. [ISP(+)] strains carrying hal3Delta deletion cannot be cured from [ISP(+)] in the presence of GuHCl. Since Hal3p is a negative regulatory subunit of Ppz1 protein phosphatase, consequences of PPZ1 over-expression and deletion are opposite to those of HAL3. The observed effects are mediated by the catalytic function of Ppz1 and are probably related to the participation of Ppz1 in regulation of eEF1Balpha elongation factor activity. Importantly, [ISP(+)] status of yeast strains is determined by fluctuation in Hal3p level, since [ISP(+)] strains have less Hal3p than their [isp(-)] derivatives obtained by GuHCl treatment. A model considering epigenetic (possibly prion) regulation of Hal3p amount as a mechanism underlying [ISP(+)] status of yeast cell is suggested.     

Mechanical and microstructural properties of hybrid poly(ethylene glycol)-soy protein hydrogels for wound dressing applications

Biomimetic hydrogel made of poly(ethylene glycol) and soy protein with a water content of 96% has been developed for moist wound dressing applications. In this study, such hybrid hydrogels were investigated by both tensile and unconfined compression measurements in order to understand the relationships between structural parameters of the network, its mechanical properties and protein absorption in vitro. Elastic moduli were found to vary from 1 to 17 kPa depending on the composition, while the Poisson's ratio (approximately 0.18) and deformation at break (approximately 300%) showed no dependence on this parameter. Further calculations yielded the crosslinking concentration, the average molecular weight between crosslinks (M(C)) and the mesh size. The results show that reactions between PEG and protein create polymeric chains comprising molecules of PEG and protein fragments between crosslinks. M(C) is three times higher than that expected for a "theoretical network." On the basis of this data, we propose a model for the 3D network of the hydrogel, which is found to be useful for understanding drug release properties and biomedical potential of the studied material.     

New data on Microphallus breviatus Deblock & Maillard, 1975 (Microphallidae: Digenea) with emphasis on the evolution of dixenous life cycles of microphallids

Infection by intramolluscan stages of Microphallus breviatus Deblock & Maillard, 1975 are common in Hydrobia ventrosa mudsnails in Iceland. Cercariae encyst inside the daughter sporocysts and develop there into metacercariae that become infective for the definitive hosts which are probably charadriiform waders. The adult stage was obtained in 1-day-old chicks that were experimentally infected with metacercariae from naturally infected hydrobians. New data are presented on the morphology and biology of the cercariae, and the adult is described for the first time. Comparisons are made between M. breviatus and closely related species. Differential diagnosis of M. breviatus is given. The morphological specializations in larvae of the hermaphroditic generation of the microphallids accompanying transition from trixenous life cycles to dixenous ones are considered, and the applicability of the term “life-cycle truncation” to microphallids with dixenous life cycles is discussed. Also, reasons for the broad distribution of dixenous life cycles within the family Microphallidae are reviewed.     

Trabecular metal acetabular components in primary total hip arthroplasty

Background and purpose — Trabecular metal (TM) cups have demonstrated favorable results in acetabular revision and their use in primary total hip arthroplasty (THA) is increasing. Some evidence show that TM cups might decrease periprosthetic infection (PPI) incidence. We compared the survivorship of TM cups with that of other uncemented cups in primary THA, and evaluated whether the use of TM cups is associated with a lower risk of PPI.

Patients and methods — 10,113 primary THAs with TM cup and 85,596 THAs with other uncemented cups from 2 high-quality national arthroplasty registries were included. The mean follow-up times were 3.0 years for the TM cups and 3.8 years for the other uncemented cups.

Results — The overall survivorship up to 8 years for TM cups and other uncemented cups was 94.4% and 96.2%, respectively (p = < 0.001). Adjusting for relevant covariates in a Cox regression model the TM cups had a persistently higher revision risk than other uncemented cups (HR =1.5, 95% CI 1.4–1.7, p = < 0.001). There was a slightly higher, though not statistically significant, revision rate for PPI in the TM group (1.2, 95% CI 1.0–1.6, p = 0.09).

Interpretation — Risk of revision for any reason was higher for the TM cup than for other uncemented cups in primary THA. In contrast to our hypothesis, there was no evidence that the revision rate for PPI was lower in the TM cup patients. Regardless of the promising early and mid-term results for TM cups in hip revision arthroplasty, we would like to sound a note of caution on the increasing use of the TM design, especially in uncomplicated primary THAs, where uncemented titanium cups are considered to provide a reliable outcome.     

Binaural interactions of electrically and acoustically evoked responses recorded from the inferior colliculus of guinea pigs

Binaural interactions within the inferior colliculus (IC) elicited by electric and acoustic stimuli were investigated in this study. Using a guinea pig model, binaural acoustic stimuli were presented with different time delays, as were combinations of binaural electric and acoustic stimuli. Averaged evoked potentials were measured using electrodes inserted into the central nucleus of the IC to obtain the binaural interaction component (BIC), computed by subtracting the sum of the two monaural responses from the binaural response. The BICs to acoustic-acoustic stimulation and electric-acoustic stimulation were found to be similar. The BIC amplitude increased with stimulus intensity, but the shapes of the delay functions were similar across the levels tested. The gross-potential data are thus consistent with the thesis that the central auditory system processes binaural electric and acoustic stimuli in a similar manner. These results suggest that the binaural auditory system can process combinations of electric and acoustic stimulation presented across ears and that evoked gross potentials may be used to measure such interaction.     

Does BMI influence hospital stay and morbidity after fast-track hip and knee arthroplasty?

Background and purpose — Body mass index (BMI) outside the normal range possibly affects the perioperative morbidity and mortality following total hip arthroplasty (THA) and total knee arthroplasty (TKA) in traditional care programs. We determined perioperative morbidity and mortality in such patients who were operated with the fast-track methodology and compared the levels with those in patients with normal BMI.

Patients and methods — This was a prospective observational study involving 13,730 procedures (7,194 THA and 6,536 TKA operations) performed in a standardized fast-track setting. Complete 90-day follow-up was achieved using national registries and review of medical records. Patients were grouped according to BMI as being underweight, of normal weight, overweight, obese, very obese, and morbidly obese.

Results — Median length of stay (LOS) was 2 (IQR: 2–3) days in all BMI groups.

30-day re-admission rates were around 6% for both THA (6.1%) and TKA (5.9%), without any statistically significant differences between BMI groups in univariate analysis (p > 0.4), but there was a trend of a protective effect of overweight for both THA (p = 0.1) and TKA (p = 0.06).

90-day re-admission rates increased to 8.6% for THA and 8.3% for TKA, which was similar among BMI groups, but there was a trend of lower rates in overweight and obese TKA patients (p = 0.08 and p = 0.06, respectively). When we adjusted for preoperative comorbidity, high BMI in THA patients (very obese and morbidly obese patients only) was associated with a LOS of >4 days (p = 0.001), but not with re-admission. No such relationship existed for TKA.

Interpretation — A fast-track setting resulted in similar length of hospital stay and re-admission rates regardless of BMI, except for very obese and morbidly obese THA patients.     

Processing of facial emotion in the human fusiform gyrus

Electrophysiological and fMRI-based investigations of the ventral temporal cortex of primates provide strong support for regional specialization for the processing of faces. These responses are most frequently found in or near the fusiform gyrus, but there is substantial variability in their anatomical location and response properties. An outstanding question is the extent to which ventral temporal cortex participates in processing dynamic, expressive aspects of faces, a function usually attributed to regions near the superior temporal cortex. Here, we investigated these issues through intracranial recordings from eight human surgical patients. We compared several different aspects of face processing (static and dynamic faces; happy, neutral, and fearful expressions) with power in the high-gamma band (70-150 Hz) from a spectral analysis. Detailed mapping of the response characteristics as a function of anatomical location was conducted in relation to the gyral and sulcal pattern on each patient's brain. The results document responses with high responsiveness for static or dynamic faces, often showing abrupt changes in response properties between spatially close recording sites and idiosyncratic across different subjects. Notably, strong responses to dynamic facial expressions can be found in the fusiform gyrus, just as can responses to static faces. The findings suggest a more complex, fragmented architecture of ventral temporal cortex around the fusiform gyrus, one that includes focal regions of cortex that appear relatively specialized for either static or dynamic aspects of faces.     

Sequential Turning Acquisition and Reconstruction (STAR) method for four-dimensional imaging of cyclically moving structures

Optical coherence tomography allows for dynamic, three-dimensional (3D+T) imaging of the heart within animal embryos. However, direct 3D+T imaging frame rates remain insufficient for cardiodynamic analysis. Previously, this limitation has been addressed by reconstructing 3D+T representations of the beating heart based on sets of two-dimensional image sequences (2D+T) acquired sequentially at high frame rate and in fixed (and parallel) planes throughout the heart. These methods either require additional hardware to trigger the acquisition of each 2D+T series to the same phase of the cardiac cycle or accumulate registration errors as the slices are synchronized retrospectively by pairs, without a gating signal. Here, we present a sequential turning acquisition and reconstruction (STAR) method for 3D+T imaging of periodically moving structures, which does not require any additional gating signal and is not prone to registration error accumulation. Similarly to other sequential cardiac imaging methods, multiple fast image series are consecutively acquired for different sections but in between acquisitions, the imaging plane is rotated around the center line instead of shifted along the direction perpendicular to the slices. As the central lines of all image-sequences coincide and represent measurements of the same spatial position, they can be used to accurately synchronize all the slices to a single inherent reference signal. We characterized the accuracy of our method on a simulated dynamic phantom and successfully imaged a beating embryonic rat heart. Potentially, this method can be applied for structural or Doppler imaging approaches with any direct space imaging modality such as computed tomography, ultrasound, or light microscopy.