A Bibliometric Analysis of the Field of Computer-Assisted Orthopedic Surgery during 2002-2021.

Background: This study aimed to investigate the characteristics of research articles and research trends in computer-assisted orthopedic surgery (CAOS) by conducting bibliometric analyses. Methods: CAOS-related research articles published in international journals from 2002 to 2021 were collected using the PubMed database and analyzed using the bibliometric method. Their publication year, journal name, corresponding author's country name, and the number of citations of all collected articles were noted. Contents of the articles were analyzed to evaluate the time point and anatomical site at which the digital technique was applied. Further, the 20-year period was divided into two halves of 10 years each to analyze the research trends. Results: A total of 639 CAOS-related articles were identified. An average of 32.0 CAOS-related articles were published annually, with an average of 20.6 and 43.3 published in the first half and second half, respectively. Of all articles, 47.6% were published in the top 10 journals, and 81.2% were written in the top 10 countries. The total numbers of citations were 11.7 and 6.3 in the first and second halves, respectively, but the average annual number of citations was higher in the second half than in the first one. Articles on application of digital techniques during surgery were 62.3% and those on pre-surgery application were 36.9%. Further, articles in the knee (39.0%), spine (28.5%), and hip and pelvis (21.5%) fields accounted for 89.0% of the total publications. But the increase in publications in the said period was highest in the fields of the hand and wrist (+1,300.0%), ankle (+466.7%), and shoulder (+366.7%). Conclusions: Over the last 20 years, the publication of CAOS-related research articles in international journals has grown steadily. Although the knee, spine, hip, and pelvis fields account for most CAOS-related research, research in new fields is also increasing. This study analyzed the types of articles and trends in CAOS-related research and provided useful information for future research in the field of CAOS.

Surgery-related anxiety on geriatric patients undergoing total knee arthroplasty: a retrospective observational study.

BACKGROUND: The prevalence of anxiety in patients undergoing total knee arthroplasty (TKA) and its association with postoperative functions are well known; however, the levels of anxiety or anxiety-related characteristics are unknown. This study aimed to investigate the prevalence of clinically significant state anxiety in geriatric patients undergoing TKA for osteoarthritis (OA) of the knee and to evaluate the anxiety-related characteristics experienced by these patients pre- and post-operatively. METHODS: This retrospective observational study recruited patients who had undergone TKA for knee OA using general anesthesia between February 2020 and August 2021. The study participants were geriatric patients older than 65 years who had moderate or severe OA. We evaluated patient characteristics including age, sex, body mass index, smoking status, hypertension, diabetes, and cancer. We assessed their levels of anxiety status using the STAI-X which comprises 20-item scales. Clinically meaningful state anxiety was defined as a total score of 52 or higher. An independent Student's t-test was used to determine differences of STAI score between subgroups in terms of patient characteristics. And patients were asked to complete questionnaires, which assessed four areas: (1) the main cause of anxiety; (2) the most helpful factor in overcoming anxiety before surgery; (3) the most helpful factor in reducing anxiety after surgery; and (4) the most anxious moment during the entire process. RESULTS: The mean STAI score of patients who underwent TKA was 43.0 points and 16.4% of patients experienced clinically significant state anxiety. The current smoking status affect STAI score and the proportion of patients with clinically meaningful state anxiety. The most common cause of preoperative anxiety was the surgery itself. Overall, 38% of patients reported that they experienced the greatest level of anxiety when the surgeon had recommended TKA in the outpatient clinic. The trust in the medical staff before surgery and the surgeon's explanations after surgery helped the most in reducing anxiety. CONCLUSIONS: One in six patients before TKA experience clinically meaningful state anxiety, and about 40% of patients experience anxiety from the time they are recommended for surgery. Patients tended to overcome anxiety before TKA through trust in the medical staff, and the surgeon's explanations after surgery was found to be helpful in reducing anxiety.

Fabrication of a Tailored, Hybrid Extracellular Matrix Composite.

The extracellular matrix (ECM) is a network of connective fibers that supports cells living in their surroundings. Native ECM, generated by the secretory products of each tissue's resident cells, has a unique architecture with different protein composition depending on the tissue. Therefore, it is very difficult to artificially design in vivo architecture in tissue engineering. In this study, a hybrid ECM scaffold from the basic structure of fibroblast-derived cellular ECMs is fabricated by adding major ECM components of fibronectin (FN) and collagen (COL I) externally. It is confirmed that while maintaining the basic structure of the native ECM, major protein components can be regulated. Then, decellularization is performed to prepare hybrid ECM scaffolds with various protein compositions and it is demonstrated that a liver-mimicking fibronectin (FN)-rich hybrid ECM promoted successful settling of H4IIE rat hepatoma cells. The authors believe that their method holds promise for the fabrication of scaffolds that provide a tailored cellular microenvironment for specific organs and serve as novel pathways for the replacement or regeneration of specific organ tissues.

Does spiked tibial cement spacer reduce spacer-related problems in two-stage revision total knee arthroplasty for infection?

PURPOSE: Articulating cement spacers are frequently used in staged approaches for infected total knee arthroplasty (TKA). This study investigated whether a tibial cement spacer (TCS) with spikes could reduce spacer-related problems in two-stage revision TKA (R-TKA). METHODS: A total of 27 patients (27 knees; 10 men and 17 women) who underwent two-stage R-TKA for infected TKA were retrospectively analyzed. Group A comprised 12 patients who used TCS with spikes added to the bottom surface, whereas group B consisted of 15 patients who used conventional TCS with a flat bottom. For each group, plain radiographs were obtained after cement spacer implantation and before R-TKA to measure mediolateral (ML) translation and TCS's tilting angle. Patients' demographic data, ML translation of the TCS, and changes in the TCS's tilting angle between the groups were analyzed. RESULTS: The mean ML translation was significantly lower in group A than that in group B (1.7 mm vs. 5.4 mm, p = 0.04). The mean change in the tilting angle was significantly lower in group A than that in group B (4.5° vs. 19.4°, p = 0.047). CONCLUSION: The spiked TCS in two-stage R-TKA provides superior stability compared to the TCS with a conventional design.

An Accelerated Wound-Healing Surgical Suture Engineered with an Extracellular Matrix.

A suture is a ubiquitous medical device to hold wounded tissues together and support the healing process after surgery. Surgical sutures, having incomplete biocompatibility, often cause unwanted infections or serious secondary trauma to soft or fragile tissue. In this research, UV/ozone (UVO) irradiation or polystyrene sulfonate acid (PSS) dip-coating is used to achieve a fibronectin (FN)-coated absorbable suture system, in which the negatively charged moieties produced on the suture cause fibronectin to change from a soluble plasma form into a fibrous form, mimicking the actions of cellular fibronectin upon binding. The fibrous fibronectin coated on the suture can be exploited as an engineered interface to improve cellular migration and adhesion in the region around the wounded tissue while preventing the binding of infectious bacteria, thereby facilitating wound healing. Furthermore, the FN-coated suture is found to be associated with a lower friction between the suture and the wounded tissue, thus minimizing the occurrence of secondary wounds during surgery. It is believed that this surface modification can be universally applied to most kinds of sutures currently in use, implying that it may be a novel way to develop a highly effective and safer suture system for clinical applications.

State-Anxiety in Geriatric Patients Undergoing Surgical Treatment for Femoral Neck or Intertrochanteric Fractures.

INTRODUCTION: Geriatric patients with hip fractures often experience unexpected falls and they may have unfamiliar and unpleasant experiences within a brief period. This study aimed to investigate the prevalence and levels of preoperative anxiety in patients undergoing surgical treatment for hip fractures, and to determine the anxiety-related characteristics experienced by patients during the period before and after surgery. MATERIALS AND METHODS: We recruited a total of 75 geriatric patients who underwent surgical treatment for hip fractures and returned complete questionnaires. We used the State-Trait Anxiety Inventory (STAI)-X type to measure state-anxiety and defined a total score of 52 or higher as clinically meaningful state-anxiety. And, we investigated main cause of anxiety, moment of the highest level of anxiety, and the most helpful factor in overcoming anxiety before surgery and in reducing anxiety after surgery. RESULTS: The mean STAI score was 47.2 points and one-third of the patients experienced various levels of clinically meaningful state-anxiety. The most common cause of preoperative anxiety was the surgery itself and patients experienced the greatest level of anxiety from the night preceding the surgery to the day of the surgery. Further, patients' trust in the medical staff prior to surgery and the surgeon's explanation after the surgery were the most key factors in overcoming anxiety. CONCLUSION: This study investigates the state-anxiety of geriatric patients undergoing surgery for hip fractures and presents important findings which can help in developing evidence-based interventions to improve the experience of patients undergoing hip surgeries.

Trends in knee surgery research in the official journal of the Korean Knee Society during the period 1999-2018: a bibliometric review.

BACKGROUND: We applied bibliometric tools to original articles published in the official journal of the Korean Knee Society between 1999 and 2018 to identify their characteristics related to knee surgery and to examine the changes in research trends in the last 20 years. METHODS: Over a 20-year period, 579 original articles were published in the journal Knee Surgery and Related Research (KSRR). We analyzed the title, keywords, and abstract of the article to analyze the research topics and assigned original articles to seven surgical categories as follows: total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), high tibial osteotomy (HTO), arthroscopy, surgery for cruciate ligament, revision surgery, and other surgery. To analyze the trends in research, we divided the study period into two equal parts of 10 years each, examined the percentage of articles in each decade, and analyzed topic trends using the growth rate. RESULTS: Among the original articles, 86 on the topic of non-surgery were excluded, and 493 original articles related surgical research were included. Articles related to surgery accounted for 85.2% of the total original articles published annually. By period, this was 85.6% in the first half and 84.8% in the late half (p = 0.76). A total of 493 original articles related to surgery, with the largest number of TKA-related research at 52.1%. In the study period, the largest increase in the percentage of articles was on the topic of HTO surgery, by 149%. The topics of UKA and revision surgery increased by 95.3% and 33.9%. The topic of TKA increased by 5.9% and the topic of surgery for cruciate ligament decreased by 18.7%. The topic of arthroscopy showed the largest decrease, by 47.6%. CONCLUSIONS: The bibliometric findings of this study suggest that the majority of surgery-related original articles published in KSRR during the last 20 years involved research about TKA surgery, and the greatest relative increase over the study period involved research about HTO surgery. The authors expect that the analysis of characteristics and research trends of original articles published in KSRR will provide useful information about KSRR for future researchers.

Isolation, cultivation, and genome analysis of proteorhodopsin-containing SAR116-clade strain Candidatus Puniceispirillum marinum IMCC1322.

Strain IMCC1322 was isolated from a surface water sample from the East Sea of Korea. Based on 16S rRNA analysis, IMCC1322 was found to belong to the OCS28 sub-clade of SAR116. The cells appeared as short vibrioids in logarithmic-phase culture, and elongated spirals during incubation with mitomycin or in aged culture. Growth characteristics of strain IMCC1322 were further evaluated based on genomic information; proteorhodopsin (PR), carbon monoxide dehydrogenase, and dimethylsulfoniopropionate (DMSP)-utilizing enzymes. IMCC1322 PR was characterized as a functional retinylidene protein that acts as a light-driven proton pump in the cytoplasmic membrane. However, the PR-dependent phototrophic potential of strain IMCC1322 was only observed under CO-inhibited and nutrient-limited culture conditions. A DMSP-enhanced growth response was observed in addition to cultures grown on C1 compounds like methanol, formate, and methane sulfonate. Strain IMCC1322 cultivation analysis revealed biogeochemical processes characteristic of the SAR116 group, a dominant member of the microbial community in euphotic regions of the ocean. The polyphasic taxonomy of strain IMCC1322 is given as Candidatus Puniceispirillum marinum, and was confirmed by chemotaxonomic tests, in addition to 16S rRNA phylogeny and cultivation analyses.

Iatrogenic Medial Collateral Ligament Injury by Valgus Stress During Arthroscopic Surgery of the Knee.

PURPOSE: To evaluate the radiographic and clinical follow-up results of iatrogenic medial collateral ligament (MCL) injuries caused by valgus stress during arthroscopic surgery of the knee. METHODS: This study retrospectively evaluated 15 knees in 15 patients (8 female and 7 male patients), with a mean age of 58 years (range, 45-66 years), with iatrogenic MCL injuries caused by valgus stress during arthroscopic surgery of the knee. All patients were treated conservatively without an immobilizer or brace. The mean follow-up period was 24 months (range, 18-51 months). Evaluations included magnetic resonance imaging immediately postoperatively, as well as physical examinations and valgus stress radiographs (at 0° and 30° of knee flexion) 6 weeks after surgery and at final follow-up. RESULTS: Postoperative magnetic resonance imaging in all patients showed increased signal intensity, swelling, and partial loss of continuity at the meniscofemoral portion of the MCL. Physical examination showed mild tenderness in only 1 patient after 6 weeks and none at final follow-up. Valgus stress tests and valgus stress radiographs showed no significant differences between the injured and uninjured knees at 6 weeks postoperatively and at final follow-up (P > .05). CONCLUSIONS: Iatrogenic MCL injuries during arthroscopic knee surgery could be treated successfully without a splint or brace. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Photosynthetic artificial organelles sustain and control ATP-dependent reactions in a protocellular system.

Inside cells, complex metabolic reactions are distributed across the modular compartments of organelles. Reactions in organelles have been recapitulated in vitro by reconstituting functional protein machineries into membrane systems. However, maintaining and controlling these reactions is challenging. Here we designed, built, and tested a switchable, light-harvesting organelle that provides both a sustainable energy source and a means of directing intravesicular reactions. An ATP (ATP) synthase and two photoconverters (plant-derived photosystem II and bacteria-derived proteorhodopsin) enable ATP synthesis. Independent optical activation of the two photoconverters allows dynamic control of ATP synthesis: red light facilitates and green light impedes ATP synthesis. We encapsulated the photosynthetic organelles in a giant vesicle to form a protocellular system and demonstrated optical control of two ATP-dependent reactions, carbon fixation and actin polymerization, with the latter altering outer vesicle morphology. Switchable photosynthetic organelles may enable the development of biomimetic vesicle systems with regulatory networks that exhibit homeostasis and complex cellular behaviors.

Growth retardation of Escherichia coli by artificial increase of intracellular ATP.

Overexpression of phosphoenolpyruvate carboxykinase (PCK) was reported to cause the harboring of higher intracellular ATP concentration in Escherichia coli, accompanied with a slower growth rate. For systematic determination of the relationship between the artificial increase of ATP and growth retardation, PCKWT enzyme was directly evolved in vitro and further overexpressed. The evolved PCK67 showed a 60% greater catalytic efficiency than that of PCKWT. Consequently, the PCK67-overexpressing E. coli showed the highest ATP concentration at the log phase of 1.45 µmol/gcell, with the slowest growth rate of 0.66 h(-1), while the PCKWT-overexpressing cells displayed 1.00 µmol/gcell ATP concentration with the growth rate of 0.84 h(-1) and the control had 0.28 µmol/gcell with 1.03 h(-1). To find a plausible reason, PCK-overexpressing cells in a steady state during chemostat growth were applied to monitor intracellular reactive oxygen species (ROS). Higher amount of intracellular ROS were observed as the ATP levels increased. To confirm the hypothesis of slower growth rate without perturbation of the carbon flux by PCK-overexpression, phototrophic Gloeobacter rhodopsin (GR) was expressed. The GR-expressing strain under illumination harbored 81% more ATP concentration along with 82% higher ROS, with a 54% slower maximum growth rate than the control, while both the GR-expressing strain under dark and dicarboxylate transporter (a control membrane protein)-expressing strain showed a lower ATP and increased ROS, and slower growth rate. Regardless of carbon flux changes, the artificial ATP increase was related to the ROS increase and it was reciprocally correlated to the maximum growth rate. To verify that the accumulated intracellular ROS were responsible for the growth retardation, glutathione was added to the medium to reduce the ROS. As a result, the growth retardation was restored by the addition of 0.1 mM glutathione. Anaerobic culture even enabled the artificial ATP-increased E. coli to grow faster than control. Collectively, it was concluded that artificial ATP increases inhibit the growth of E. coli due to the overproduction of ROS.

Light-driven Na(+) pump from Gillisia limnaea: a high-affinity Na(+) binding site is formed transiently in the photocycle.

A group of microbial retinal proteins most closely related to the proton pump xanthorhodopsin has a novel sequence motif and a novel function. Instead of, or in addition to, proton transport, they perform light-driven sodium ion transport, as reported for one representative of this group (KR2) from Krokinobacter. In this paper, we examine a similar protein, GLR from Gillisia limnaea, expressed in Escherichia coli, which shares some properties with KR2 but transports only Na(+). The absorption spectrum of GLR is insensitive to Na(+) at concentrations of ≤3 M. However, very low concentrations of Na(+) cause profound differences in the decay and rise time of photocycle intermediates, consistent with a switch from a "Na(+)-independent" to a "Na(+)-dependent" photocycle (or photocycle branch) at ∼60 µM Na(+). The rates of photocycle steps in the latter, but not the former, are linearly dependent on Na(+) concentration. This suggests that a high-affinity Na(+) binding site is created transiently after photoexcitation, and entry of Na(+) from the bulk to this site redirects the course of events in the remainder of the cycle. A greater concentration of Na(+) is needed for switching the reaction path at lower pH. The data suggest therefore competition between H(+) and Na(+) to determine the two alternative pathways. The idea that a Na(+) binding site can be created at the Schiff base counterion is supported by the finding that upon perturbation of this region in the D251E mutant, Na(+) binds without photoexcitation. Binding of Na(+) to the mutant shifts the chromophore maximum to the red like that of H(+), which occurs in the photocycle of the wild type.

Cyanobacterial light-driven proton pump, gloeobacter rhodopsin: complementarity between rhodopsin-based energy production and photosynthesis.

A homologue of type I rhodopsin was found in the unicellular Gloeobacter violaceus PCC7421, which is believed to be primitive because of the lack of thylakoids and peculiar morphology of phycobilisomes. The Gloeobacter rhodopsin (GR) gene encodes a polypeptide of 298 amino acids. This gene is localized alone in the genome unlike cyanobacterium Anabaena opsin, which is clustered together with 14 kDa transducer gene. Amino acid sequence comparison of GR with other type I rhodopsin shows several conserved residues important for retinal binding and H+ pumping. In this study, the gene was expressed in Escherichia coli and bound all-trans retinal to form a pigment (λmax  = 544 nm at pH 7). The pKa of proton acceptor (Asp121) for the Schiff base, is approximately 5.9, so GR can translocate H+ under physiological conditions (pH 7.4). In order to prove the functional activity in the cell, pumping activity was measured in the sphaeroplast membranes of E. coli and one of Gloeobacter whole cell. The efficient proton pumping and rapid photocycle of GR strongly suggests that Gloeobacter rhodopsin functions as a proton pumping in its natural environment, probably compensating the shortage of energy generated by chlorophyll-based photosynthesis without thylakoids.

Symptomatic mucoid degeneration of the anterior cruciate ligament.

PURPOSE: Mucoid degeneration of the anterior cruciate ligament (ACL) is a little-known entity. The aim of this study was to detail the clinical, radiological, arthroscopic and pathological findings of this condition and to report clinical outcomes following arthroscopic partial excision of the ACL. METHODS: Between 1999 and 2009, 80 knees in 78 patients were diagnosed as having mucoid degeneration of the ACL based on MRI and clinical findings, and subsequently underwent arthroscopic treatment. Of these, 68 knees in 66 patients, with a median age of 51 years (range, 35-75 years), were followed-up for at least one year. RESULTS: All patients had insidious onset of knee pain, while 56 knees (82 %) had associated extension deficits and 36 knees (53 %) had restricted flexion. MRI findings typically showed diffuse thickening and increased signal intensity of the ACL. Arthroscopic examination revealed notch impingement and bulging of hypertrophied ACL into lateral compartments. Associated lesions included meniscal tears in 33 knees and chondral lesions of at least Outerbridge grade 2 in 56 knees. All knees underwent arthroscopic partial excision of the hypertrophied ACL, with three undergoing preoperative and 30 undergoing concomitant meniscectomies. Pain relief was achieved in 58 of 62 knees (94 %) following partial excision of the ACL. Extension deficits were normalized in 49 of 56 knees (88 %), and restricted flexion was normalized in 33 of 36 affected knees (92 %). Four knees of four patients had postoperative symptoms of anterior instability. CONCLUSIONS: Pain and limitation of motion due to mucoid degeneration of the ACL can be improved by arthroscopic partial excision of the ACL with or without notchplasty. However, one potential complication is the development of postoperative symptoms of anterior instability. LEVEL OF EVIDENCE: Retrospective study, Level IV.

3D CT analysis of femoral and tibial tunnel positions after modified transtibial single bundle ACL reconstruction with varus and internal rotation of the tibia.

INTRODUCTION: We analyzed the location of femoral and tibial tunnels by three-dimensional (3D) CT reconstruction images after modified transtibial single bundle (SB) anterior cruciate ligament (ACL) reconstruction, creating a femoral tunnel with varus and internal rotation of the tibia. MATERIAL AND METHODS: Data from 50 patients (50 knees) analyzed by 3D CT after modified transtibial SB ACL reconstructions were evaluated. 3D CT images were analyzed according to the quadrant method by Bernard at the femur and the technique of Forsythe at the tibia. RESULTS: The mean distance of the femoral tunnel center locations parallel to the Blumensaat's line was 29.6%±1.9% along line t measured from the posterior condylar surface. The mean distances perpendicular to the Blumensaat's line were 37.9%±2.5% along line h measured from the Blumensaat's line. At the tibia, the mean anterior-to-posterior distance for the tunnel center location was 37.8%±1.2% and the mean medial-to-lateral distance was 50.4%±0.9%. DISCUSSION: The femoral and tibial tunnels after modified transtibial SB ACL reconstruction creating a femoral tunnel with varus and internal rotation of the tibia (figure-of-4 position) were located between the anatomical anteromedial and posterolateral footprints.

Relation between mucoid degeneration of the anterior cruciate ligament and posterior tibial slope.

PURPOSE: The purpose was to analyze the association between posterior tibial slope (PTS) and mucoid degeneration of the anterior cruciate ligament (ACL). METHODS: From October 1999 to May 2010, 84 arthroscopies were performed in 82 patients (18 men and 64 women) with mucoid degeneration of the ACL. The mean patient age was 53 years (range, 25 to 75 years). In addition to this patient group (group I), the study included a control group without mucoid degeneration of the ACL that was randomly matched for age, sex, body mass index, left or right side, and associated lesions (group II). For each group, the diagnosis was made by use of magnetic resonance imaging and arthroscopy, and a plain lateral radiograph was used to measure the PTS. RESULTS: The mean PTS was 13.5° ± 2.6° (range, 8.2° to 19.5°) in group I and 9.4° ± 2.5° (range, 4.8° to 15.5°) in group II. The mean PTS in group I was significantly greater than that in group II (P < .001). For group I, the mean PTS of the involved knee was significantly greater than that of the uninvolved contralateral knee (P = .044). There were no differences according to age, sex, left or right side, body weight, and body mass index (P > .05). CONCLUSIONS: Mucoid degeneration of the ACL was found to be associated with an increased PTS. The patients with mucoid degeneration of the ACL had a greater mean PTS than matched control patients (13.5° v. 9.4°, P < .001). LEVEL OF EVIDENCE: Level III, diagnostic study of nonconsecutive patients without consistently applied gold standard.

ATP regeneration system using E. coli ATP synthase and Gloeobacter rhodopsin and its stability.

Great efforts in using non-photosynthetic bacteria as light-utilizing bacteria for producing biomaterials have been developed recently as increasing interest in renewable resources such as light energy. With respect to producing bio-materials industrially such as food ingredients and amino acids, huge amount of adenosine-5'-triphosphate (ATP) is required. In this work, we developed a bio-ATP-synthesis system using ATP synthase of Escherichia coil as a biocatalyst and a microbial rhodopsin which is from primitive cyanobacteria, Gloeobacter violaceus. Gloeobacter rhodopsin (GR) is a light-driven proton pump. Besides electro-chemical gradient produced by cellular respiration system, GR produces a proton gradient using light illumination which is used in additional driving force of synthesizing ATP by ATP synthase. Inverted membrane vesicle was prepared so that it could be incorporated with both of GR and ATP synthase and produced ATP in the exterior side of the vesicle in the presence of light. Since inverted membrane vesicle does not contain precursors for ATP, we added ADP and inorganic phosphate (P(i)). Then, we measured the amounts of ATP produced by ATP synthase in the presence of light. As the average value of 6 samples, 4.79 x 10(-2) micromole of ATP produced for 1 microg of GR per minute. Also, we measured again after 7 days and 65 days, respectively, in order to check the stability of the bio-ATP-synthesis system. Amount of ATP produced decayed double-exponentially and an expected value of half-life of the system was 1.5 days and 39.7 days. Our results demonstrate that ATP was regenerated successfully by using GR and ATP synthase. However, the stability of ATP synthase should be increased to use this system industrially in the near future.

High-flexion total knee arthroplasty improves flexion of stiff knees.

PURPOSE: High-flexion knee prosthesis designs are generally thought to be of benefit only in patients with a satisfactory preoperative flexion angle. The aim of the study was to evaluate whether high-flexion designs were indeed worthless in osteoarthritis patients with severe preoperative flexion limitation. METHODS: The postoperative maximum flexion was compared in osteoarthritis patients with a preoperative maximum flexion of 100° or less, using LPS and LPS-flex implants (NexGen®; Zimmer, Warsaw, IN) in total knee arthroplasties. Data on 39 knees in the LPS group and 41 in the LPS-flex group, with a minimum of 2 years of follow-up, were reviewed retrospectively, focused on the postoperative maximum flexion. RESULTS: Two years after operation, the LPS-flex group had a mean postoperative maximum flexion of 131±10° (range, 105-140°), which was significantly higher than the 121±12° (range, 95-140°) in the LPS group (P<0.001). In the LPS-flex group, about half of the knees (n=18, 44%) could achieve a maximum flexion of 140° postoperatively, but in the LPS group only five knees (13%) achieved a maximum flexion of 140°. CONCLUSION: Despite a different period of the operation between groups, this study suggested that osteoarthritis patients with severe preoperative flexion limitation could achieve more postoperative gain in flexion when a high-flexion prosthesis was used, compared to the flexion obtained using a standard prosthesis.

Cyanobacterial phytochrome Cph2 is a negative regulator in phototaxis toward UV-A.

We investigated the wavelength dependence and photon-fluence rate response relationship for phototaxis of wild-type and a cyanobacterial phytochrome 2 (cph2) mutant in cyanobacterium Synechocystis sp. PCC 6803. Compared to wild-type, the cph2 mutant exhibited maximal activity for positive phototaxis at the near-UV spectral range. Two cysteine to serine substitutions in two chromophore-binding domains showed a similar cph2 mutant phenotype under UV-A. Epistasis of a pixJ mutation over a cph2 mutation implied that pixJ gene acts downstream of the cph2 gene with respect to UV-A-induced positive phototaxis. Therefore, we suggest that Cph2 is essential for the inhibition of positive phototaxis toward UV-A.