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► A combination of laser desorption and supersonic jet-cooling is used to produce base pairs of adenine nucleosides. ► Stacked base-pair structure of N6,N6-dimethyladnosine is ...identified by IR vibrational spectroscopy. ► Anharmonic vibrational calculation is employed to analyze the vibrational mode coupling in the stacked base pair.
We have employed a laser desorption technique combined with supersonic-jet cooling for producing base pairs of adenine nucleosides, adenosine (Ado) and N6,N6-dimethyladenosine (DMAdo) under low-temperature conditions. The resulting base pairs are then ionized through resonant two-photon ionization (R2PI) and analyzed by time-of-flight mass spectrometry. It is found that dimers of these adenine nucleosides are stable, especially in the case of DMAdo, with respect to those of the corresponding bases, i.e., adenine and N6,N6-dimethyladenine. Structural analysis of the DMAdo dimer is performed based on the IR–UV double resonance measurements and theoretical calculations. The result demonstrates that the dimer possesses a stacked structure being stabilized by the formation of hydrogen-bonding network involving the two sugar groups. The occurrence of the frequency shift and broadening is explained satisfactorily based on the anharmonic coupling of the OH stretching modes with specific bending modes and low-frequency modes of base and sugar moieties.
Fundamental vibrations of the chromophore in the membrane protein bacteriorhodopsin (BR), a protonated Schiff base retinal, have been studied for decades, both by resonance Raman and by infrared (IR) ...difference spectroscopy. Such studies started comparing vibrational changes between the initial BR state (all-
retinal) and the K intermediate (13-
retinal), being later extended to the rest of intermediates. They contributed to our understanding of the proton-pumping mechanism of BR by exploiting the sensitivity of fundamental vibrational transitions of the retinal to its conformation. Here, we report on new bands in the 2,500 to 1,800 cm
region of the K-BR difference FT-IR spectrum. We show that the bands between 2,500 and 2,300 cm
originate from overtone and combination transitions from C-C stretches of the retinal. We assigned bands below 2,300 cm
to the combination of retinal C-C stretches with methyl rocks and with hydrogen-out-of-plane vibrations. Remarkably, experimental C-C overtone bands appeared at roughly twice the wavenumber of their fundamentals, with anharmonic mechanical constants ≤3.5 cm
, and in some cases of ∼1 cm
. Comparison of combination and fundamental bands indicates that most of the mechanical coupling constants are also very small. Despite the mechanical quasi-harmonicity of the C-C stretches, the area of their overtone bands was only ∼50 to ∼100 times smaller than of their fundamental bands. We concluded that electrical anharmonicity, the second mechanism giving intensity to overtone bands, must be particularly high for the retinal C-C stretches. We corroborated the assignments of negative bands in the K-BR difference FT-IR spectrum by ab initio anharmonic vibrational calculations of all-trans retinal in BR using a quantum-mechanics/molecular mechanics approach, reproducing reasonably well the small experimental anharmonic and coupling mechanical constants. Yet, and in spite accounting for both mechanical and electrical anharmonicities, the intensity of overtone C-C transitions was underestimated by a factor of 4-20, indicating room for improvement in state-of-the-art anharmonic vibrational calculations. The relatively intense overtone and combination bands of the retinal might open the possibility to detect retinal conformational changes too subtle to significantly affect fundamental transitions but leaving a footprint in overtone and combination transitions.
It has been reported that Modic change of the lumbar spine endplate includes three types: i.e. . edema or inflammation for type 1, fatty marrow change for type 2 and sclerotic change for type 3. ...Basically, type 1 Modic change may be related to the chronic low back pain. There are two kinds of the treatment for the type 1 Modic change to heal the pain : the anti-inflammatory drugs, and intra-discal injection of steroid. When the inflammatory change would be intractable, surgical intervention is needed. The gold standard for the surgical intervention is the segmental fusion of the affected level. The fusion surgery may cause the adjacent degeneration ; thus, motion preservation surgery is better, if possible. Our department started the motion preservation full-endoscopic intradiscal debridement surgery for this pathology, since some of the type 1 Modic change may be chronic discitis by P. Acnes. In this paper, we describe the first patient of type 1 Modic change who was successfully treated by the full-endoscopic intra-discal debridement and drainage under the local anesthesia. We named this procedure as transforaminal full-endoscopic disc cleaning surgery (FEDC). Finally, pathology, conservative and surgical intervention of Modic change was discussed. J. Med. Invest. 68 : 1-5, February, 2021
We have conducted combined time-resolved ATR-FTIR and proton conductivity measurements of a sulfonated block poly(arylene ether sulfone ketone) membrane, to be called a SPE-bl-1 membrane hereafter, ...during the hydration/dehydration cycle at room temperature. The result was discussed in comparison with the Nafion NRE211 membrane. Dissociation of the sulfonic acid groups and conductivity change were interpreted in terms of different states of water in the membrane characterized by δ(HOH) bands at 1705 and 1637 cm–1, respectively. The former is assigned to hydrated protons produced by the dissociation followed by hydration. Proton conductivity increases significantly, over 0.1–0.2 S cm–1, after the dissociation is completed at the initial stage of hydration, which is common to both membranes. The 1637 cm–1 band contains contributions from the water in the proton conduction channels as well as some water which is hydrogen bonded to the polar groups in the SPE-bl-1 membrane such as ether (COC), sulfonyl (OSO), and carbonyl (CO). The presence of the latter water lowers the effectiveness of the water in promoting proton conduction in the membrane. It is concluded that incomplete dissociation of the sulfonic acid groups coupled by the lower effectiveness is contributing to the lower proton conductivity of SPE-bl-1 than Nafion NRE211 at low hydration levels.
In lumbar interbody fusion procedure, the beneficial effects of sagittal alignment improvement and an increase in disc height in lateral lumbar interbody fusion (LLIF) have recently been reported. On ...the other hand, in posterior lumbar interbody fusion (PLIF), number of good results from sagittal alignment improvement and an increase in disc height have also been reported. In this study, we compared the results between LLIF and PLIF.We compared cases of LLIF (49 cases) and PLIF (42 cases) at the L4-5 level, in our hospital between February 2014 and August 2017. These cases included cases of multiple disc level fixation; we did not distinguish how many disc levels were fixed. The average age was 70.4 years in LLIF cases and 70.7 years in PLIF cases. We analyzed the lordotic angle and disc height gained through the procedures and bone union at one year after surgery in both LLIF and PLIF cases at the L4-5 level.The average postoperative lordotic angle and disc height at the anterior disc rim of LLIF cases were significantly larger than those of PLIF cases. Furthermore, the increased lordotic angle and disc height at the anterior and posterior disc rim of LLIF cases were also significantly larger than those of PLIF cases. At one year after surgery, the average lordotic angle and disc height at the anterior disc rim of LLIF cases was larger than that of PLIF cases. On the other hand, the decrease in lordotic angle and disc height at the anterior disc rim of LLIF cases was larger than that of PLIF cases. Furthermore, the rate of bone union in LLIF cases was lower than that in PLIF cases at one year after surgery.In this study, improvement in the lordotic angle and disc height was more in LLIF cases than in PLIF cases. On the other hand, we should pay attention to the loss of lordotic angle and disc height, and the bone union in LLIF cases.
Lateral Lumbar Interbody Fusion (LLIF) has been getting popular. Anterior column realignment (ACR) is also to be introduced in Japan. However, potential complications due to the specificity of this ...technique has been arising. The purpose of this study is to investigate anatomical features of the anterior part of segmental artery to prevent the injury on LLIF and ACR tequnique.Thirty patients who underwent CT angiography for the purpose of the preparation of spine surgery were included in this study. Whether segmental artery may across the disc at anterior part were investigated. If the segmental artery across the disc, the distance from most lateral side of the disc to the intersection point of the disc was measured to investigate the depth of anterior retractor can insert safely. The distance from branching part of aorta to the intersection point of the disc was also measured to know the reason why the segmental artery intersect the disc.One hundred eighteen of 221 (53.4%) segmental artery from L1 to L5 have intersect the disc at anterior part, 49 of 55 at L1/2, 47 of 58 at L2/3, 20 of 58 at L3/4 and 2 of 44 at L4/5. The distance from most lateral side of the disc to the intersection point of the disc was 25.8 mm in average. The distance from branching site of aorta to the intersection point of the disc was 8.2 mm in average.Anterior part of segmental artery at disc level has not been reported, but to insert the anterior retractor or to do ACR technique, it is very important to know many of segmental arteries intersect the disc at anterior part of disc especially at L1/2, L2/3 and L3/4.
•Crosslink connectors provide improved biomechanical strength.•However, crosslink connectors have not been able to be placed for atlantoaxial fixation surgery.•We applied crosslink connectors on the ...screw heads (OHXL) during the Goel/Harms procedure.•Bone union was investigated with OHXL or without it using computed tomography.•Applying crosslink connectors provides earlier bony fusion than without crosslinks.
The goal of fixation surgery for atlantoaxial instability is to achieve solid bony fusion. Achieving bony fusion as early as possible is beneficial for patients. Although placement of a transverse cross-link connector (XL) provides greater biomechanical strength, XLs have not been able to be placed when performing the Goel/Harms procedure. Recently, placing a XL on the screw head (on-the-head XL OH-XL) has become a viable option during the Goel/Harms procedure. However, there is little evidence demonstrating whether applying an OH-XL achieves early solid bony union.
A matched-control study was conducted to investigate whether placing an OH-XLs in C1/2 fixation surgery provides earlier bone union or not. Eighteen patients who underwent atlantoaxial fusion with OH-XLs (X-group), and 17 age and sex-matched patients without OH-XLs (NX-group) were compared. Bony union was assessed using reconstructed sagittal and coronal computed tomography images.
Six months after surgery, six patients in the X-group and one patient in the NX-group achieved bony union (p = .0338). One year after surgery, 14 patients in the X-group and 4 patients in the NX-group achieved bone union (p = .0010). Two years after surgery, 17 patients in the X-group and 9 patients in the NX-group achieved bony union (p = .0011).
This is the first report of the clinical application of OH-XLs for the Goel/Harms procedure. OH-XLs yield earlier bony fusion; thus, placing OH-XLs is beneficial for atlantoaxial fixation surgery using lateral mass screws of the atlas.
Introduction: Adult spinal deformity surgery has become popular in recent years, and the incidence of proximal junctional kyphosis as post-surgical complication has increased. In this study, we ...focused on postoperative changes of the fixed upper anteversion in adult spinal deformity surgery and investigated the relationship with various spine parameters, including cervical spine alignment.Methods: We assessed 24 patients (mean age, 73.2 years; 5 men, 19 women) who corrected adult spinal deformity by fixing from pelvis to middle or lower thoracic vertebra, between December 2013 and February 2018 at our hospital. Various spinal parameters from the standing whole spine X-rays at the time of before operation, immediately after operation, and 1 year after operation (e.g., PI, PT, SS, LL, SVA, TK, T1slope, C2-7 angle, C2-7SVA) were measured. The patients were divided into two groups based on their surgical outcome: Group A is the patients whose fixed upper end tilt angle increased by more than 5° from immediately after surgery to 1 year after surgery and Group B is those in whom there was no such increase.Results: The results demonstrated a significant difference in the preoperative fixed upper end anteversion between Group A and B. However, there was no significant difference in the fixed upper anteversion immediately after the operation.Conclusions: The results suggest that, in cases with greater preoperative fixed upper end tilt angle, despite surgical correction of the inclination, the fixed upper end tilt angle might increase again in the post-surgical period, thereby increasing the possibility of proximal junctional kyphosis occurrence.
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