Artificial vision with wirelessly powered subretinal electronic implant alpha-IMS

This study aims at substituting the essential functions of photoreceptors in patients who are blind owing to untreatable forms of hereditary retinal degenerations. A microelectronic neuroprosthetic device, powered via transdermal inductive transmission, carrying 1500 independent microphotodiode-amplifier-electrode elements on a 9 mm² chip, was subretinally implanted in nine blind patients. Light perception (8/9), light localization (7/9), motion detection (5/9, angular speed up to 35 deg s⁻¹), grating acuity measurement (6/9, up to 3.3 cycles per degree) and visual acuity measurement with Landolt C-rings (2/9) up to Snellen visual acuity of 20/546 (corresponding to decimal 0.037 or corresponding to 1.43 logMAR (minimum angle of resolution)) were restored via the subretinal implant. Additionally, the identification, localization and discrimination of objects improved significantly (n = 8; p < 0.05 for each subtest) in repeated tests over a nine-month period. Three subjects were able to read letters spontaneously and one subject was able to read letters after training in an alternative-force choice test. Five subjects reported implant-mediated visual perceptions in daily life within a field of 15° of visual angle. Control tests were performed each time with the implant''s power source switched off. These data show that subretinal implants can restore visual functions that are useful for daily life.     

Variations in enzyme activity in stomach and pancreatic tissue and digesta in piglets around weaning

A study was performed to investigate the effect of weaning at 4 weeks of age on the activity of digestive enzymes in the stomach and pancreatic tissue and in digesta from 3 days prior to weaning to 9 days postweaning in 64 piglets. In stomach tissue the activity of pepsin and gastric lipase was determined. Pepsin activity declined abruptly after weaning but 5 days postweaning the weaning level was regained and in the gastric contents no change in pepsin activity was observed. Weaning did not influence the activity of gastric lipase. The activity of eight enzymes and a cofactor was measured in pancreatic tissue. The effect of weaning on the enzyme activity was highly significant for all enzymes except elastase. The activity of all enzymes remained at the weaning level during day 1–2 postweaning followed by a reduction of the activity. The activity of trypsin, carboxypeptidase A, amylase and lipase exhibited minimum activity 5 days postweaning. Trypsin activity increased to the preweaning level on day 7–9 whereas the activity of the others increased but did not reach the preweaning level. The activity of chymotrypsin, carboxypeptidase B and carboxyl ester hydrolase decreased during the entire experimental period. In digesta no effect of weaning was observed on the activity of amylase and trypsin. The activity of chymotrypsin was reduced after weaning in the proximal third of the small intestine and lipase and carboxyl ester hydrolase activity was reduced in the middle and distal parts of the small intestine after weaning. The present study shows that the activities of the digestive enzymes in the pancreatic tissue are affected by weaning. Even though the pancreatic secretion cannot be judged from these results they show that the enzymes respond differently to weaning. In general the activity of the digestive enzymes in pancreatic tissue is low on day 5 postweaning which in interaction with other factors may increase the risk of developing postweaning diarrhoea.     

Human PIEZO1 Ion Channel Functions as a Split Protein

PIEZO1 is a mechanosensitive eukaryotic cation-selective channel that rapidly inactivates in a voltage-dependent manner. We previously showed that a fluorescent protein could be encoded within the hPIEZO1 sequence without loss of function. In this work, we split the channel into two at this site and asked if coexpression would produce a functional channel or whether gating and permeation might be contained in either segment. The split protein was expressed in two segments by a bicistronic plasmid where the first segment spanned residues 1 to 1591, and the second segment spanned 1592 to 2521. When the “split protein” is coexpressed, the parts associate to form a normal channel. We measured the whole-cell, cell-attached and outside-out patch currents in transfected HEK293 cells. Indentation produced whole-cell currents monotonic with the stimulus. Single channel recordings showed voltage-dependent inactivation. The Boltzmann activation curve for outside-out patches had a slope of 8.6/mmHg vs 8.1 for wild type, and a small leftward shift in the midpoint (32 mmHg vs 41 mmHg). The association of the two channel domains was confirmed by FRET measurements of mCherry on the N-terminus and EGFP on the C-terminus. Neither of the individual protein segments produced current when expressed alone.     

Does small-sided-games’ court area influence metabolic,perceptual, and physical performance parameters of young elite basketball players?

The purpose of this study was to investigate the effect of court size on physiological responses and physical performance of young elite basketball players. Twelve male basketball players (18.6 ± 0.5 years; 88.8 ± 14.5 kg; 192.6 ± 6.5 cm) from an under-19 team performed two small-sided games (matches) with different court areas (28x15 m and 28x9 m; 28x15 and 28x9 protocols). The number of players (3x3) was kept the same in each protocol. The players performed a repeated-sprint ability (RSA) test before and after each match. Blood lactate concentration was collected before (pre) and after (post) the matches, and the session rating of perceived exertion (session-RPE) was determined 30 minutes after the match. Best and mean time in the RSA test were not different between the 28x15 and the 28x9 match protocols (p > 0.05). A significant difference was observed for lactate concentration from pre- to post-match (p < 0.05) in both protocols (28x15 and 28x9); however, there was no significant interaction between protocols. A similar session-RPE mean score (28x15: 7.2 ± 1.4 and 28x9: 6.6 ± 1.4) was detected for both protocols (p > 0.05, ES=0.41). In summary, the results of the current study suggest that the different court areas induced similar responses. Although there was no significant difference in effort perception, players tended to perceive a greater effort in the larger court size.     

Comparison of effects of static,proprioceptive neuromuscular facilitation and Mulligan stretching on hip flexion range of motion: a randomized controlled trial

The aim of this study was to compare the effects of static stretching, proprioceptive neuromuscular facilitation (PNF) stretching and Mulligan technique on hip flexion range of motion (ROM) in subjects with bilateral hamstring tightness. A total of 40 students (mean age: 21.5±1.3 years, mean body height: 172.8±8.2 cm, mean body mass index: 21.9±3.0 kg · m^-2) with bilateral hamstring tightness were enrolled in this randomized trial, of whom 26 completed the study. Subjects were divided into 4 groups performing (I) typical static stretching, (II) PNF stretching, (III) Mulligan traction straight leg raise (TSLR) technique, (IV) no intervention. Hip flexion ROM was measured using a digital goniometer with the passive straight leg raise test before and after 4 weeks by two physiotherapists blinded to the groups. 52 extremities of 26 subjects were analyzed. Hip flexion ROM increased in all three intervention groups (p<0.05) but not in the no-intervention group after 4 weeks. A statistically significant change in initial–final assessment differences of hip flexion ROM was found between groups (p<0.001) in favour of PNF stretching and Mulligan TSLR technique in comparison to typical static stretching (p=0.016 and p=0.02, respectively). No significant difference was found between Mulligan TSLR technique and PNF stretching (p=0.920). The initial–final assessment difference of hip flexion ROM was similar in typical static stretching and no intervention (p=0.491). A 4-week stretching intervention is beneficial for increasing hip flexion ROM in bilateral hamstring tightness. However, PNF stretching and Mulligan TSLR technique are superior to typical static stretching. These two interventions can be alternatively used for stretching in hamstring tightness.     

The association between sociodemographic,hormonal, tubo-ovarian factors and bacterial count in Chlamydia and Mycoplasma infections with infertility

Aim: To determine if there is an association between the Chlamydia and Mycoplasma infections with socio-demographic and clinical factors, and also with infertility. Methods: We conducted a study on 100 infertile married women and 100 control group, and collected data on the socio-demographic, hormonal and tubo-ovarian factors. The results of the endocervical swabs were analyzed for Mycoplasma and Chlamydia infection, the bacterial counts were also determined. Results: The percentage positivity to infection was significantly more among the infertile group compared to the control group, and also significantly more among the age group <30 years old. The positivity for infection with Chlamydia and/or Mycoplasma was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Further sub-analysis of the infertile group showed that positivity to Chlamydia and/or Mycoplasma infection was significantly correlated to hormonal factors, ovarian factors, irregular menstruation, and previous abortion. Regression analysis showed that hormonal, ovarian factors, and irregular menstruation were the most significant factors in the positivity to Chlamydia and Mycoplasma infection. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion. Conclusion: Infection to Chlamydia and Mycoplasma is associated to younger age (?30 years old), and occurs in the infertile women. There is an interplay between infection in younger women, irregular menstruation, hormonal, and tubo-ovarian factors with infertility. Bacterial count was significantly correlated with age, history of irregular menstruation, and history of previous abortion.     

Sucrose Synthase: Expanding Protein Function

Sucrose synthase (SUS: EC 2.4.1.13), a key enzyme in plant sucrose catabolism, is uniquely able to mobilize sucrose into multiple pathways involved in metabolic, structural, and storage functions. Our research indicates that the biological function of SUS may extend beyond its catalytic activity. This inference is based on the following observations: (a) tissue-specific, isoform-dependent and metabolically-regulated association of SUS with mitochondria and (b) isoform-specific and anoxia-responsive interaction of SUS with the voltage-dependent anion channel (VDAC), the major outer mitochondrial membrane protein. More recent work shows that both VDAC and SUS are also localized to the nucleus in maize seedling tissues. Their intricate regulation under anoxia indicates that these two proteins may have a role in inter-compartmental signaling.Key Words: sucrose synthase, mitochondria, nucleus, localization, voltage-dependent anion channel (VDAC), non-catalytic rolesThe biochemical function of a protein is encoded within its primary sequence and can often be deciphered by simple in vitro assays. The cellular or organismal function of a protein is frequently the same as its biochemical activity. However, for many proteins, the biological function cannot be easily derived based on its biochemical function. This appears to be particularly true when the gene encoding the protein has a history of duplication and is represented by a family of paralogs. In maize and other species, sucrose synthase (SUS) isoforms are almost identical in their catalytic properties.^1,2 However, the characteristic phenotypes of mutants in specific isoforms suggest that the isoforms contribute to vastly different organismal functions.^2–4 Our interest is to identify the range of functions that maize SUS isoforms may have and elucidate the molecular basis of this functional diversity. Although expression divergence and consequent variation in their cellular abundance significantly contributes to this diversity,⁵ other factors such as intracellular distribution, post-translational modifications and interacting partners,^3,4,6,7 seem to be equally critical for the functional diversification of different SUS isoforms.Our study, spurred by a bioinformatics prediction, opened up a new facet of SUS biology, in that the protein may have organelle-based functions.⁸ Our analysis indicated that two of the three maize SUS isoforms (SH1 and SUS1) partly localize to mitochondria and nuclei, compartments not related to sucrose metabolism. In addition to this isoform-specificity, the compartmentation of SUS isoforms is influenced by developmental as well as environmental cues. Furthermore, its isoform-specific interaction with the voltage-dependent anion channel (VDAC) and an apparent conservation of SUS mitochondrial targeting across plant species suggest that SUS may have novel, noncatalytic biological functions. Our recent work shows that along with SUS, VDAC is also localized to the nucleus and these two proteins are inversely regulated in these two compartments under anoxic stress, indicating SUS-VDAC interaction may play a role in inter-compartmental signaling (Fig. 1).Open in a separate windowFigure 1Current working model of SUS-VDAC interactions in maize root tip cells. Prolonged anoxia leads to de-oligomerization of VDAC and the release of SUS from mitochondria, resulting in the migration of SUS to the nucleus. We hypothesize that the nuclear accumulation of SUS signals the induction of cell death pathway leading to the death of the root tip in anoxic maize seedlings. The insets show the primary root tip and a part of the axis from aerobic and anoxic seedlings. The root tip death is indicated by Evans Blue staining pattern of the anoxic root. ≠ = SUS. □ = VDAC.SUS mitochondrial localization also provided us an opportunity to reinterpret the phylogeny of sucrose metabolism. The proposed origin of sucrose metabolism is equivocal between the proteobacterial and cyanobacterial lineages.^9,10 Our discovery of SUS inside mitochondria, absence of plastid-bound SUS or plastid-targeting information in any of the plant SUS proteins and occurrence of mitochondrial targeting information in proteobacterial SUS orthologs strongly support a proteobacterial origin of plant sucrose synthases.⁸ Based on a genome-wide analysis of E. coli proteins, Lucattini et al.¹¹ proposed that mitochondrial targeting information may have been derived from the preexisting sequences of the endosymbiont proteins. We hypothesize that, in addition to the structural features needed for mitochondrial association, the functional basis of SUS-VDAC interaction may have been recruited by plants from the prokaryotic SUS genes. Based on striking similarities between bacterial and mitochondrial porins in their structure as well as regulation by purine nucleotides and their role in the host-cell death as modulated by cellular ATP levels, Frade and Michaelidis¹² speculated that the eukaryotic programmed cell death may have been a consequence of acquiring aerobic metabolism via the endosymbiotic process. Is organellar SUS a part of this acquisition?