Concomitant Lengthening Research Articles

Perfusion computer tomography of the kidneys. Research technique. Perfusion indicators in the norm: case-control

INTRODUCTION: Perfusion computed tomography (PCT) is a contrast research technique that allows one to assess blood flow in the cortical and medulla layers of the renal parenchyma at the level of the microcirculatory bed, the influence of additional renal vessels and stenoses of the renal arteries on hemodynamics in the renal parenchyma.OBJECTIVE: To optimize the technique of perfusion computed tomography of the kidneys. Determine the most informative indicators of perfusion in the renal parenchyma in the norm. Assess the relationship between perfusion parameters and the number of renal vessels, the presence of renal artery stenosis.MATERIALS AND METHODS: PCT was performed in 46 patients with no anamnestic and clinical laboratory data on kidney disease who were undergoing examination for other pathological conditions, including 35 patients aged from 20 to 90 years (average age — 63.1 years) without hemodynamically significant stenosis and 11 patients aged from 64 to 94 years (mean age 80.3 years) with renal artery stenosis of 50% or higher. Perfusion indices were calculated using maximum slope and deconvolution algorithms, kinetic curves were plotted on a time-density graph, and color parametric maps.RESULTS: A quantitative assessment of perfusion parameters in the cortical and medulla of the kidneys, a qualitative analysis of the state of its parenchyma on color parametric maps, and the shapes of kinetic curves on the time-density graph were analyzed. Changes in perfusion parameters were established depending on the age, number and condition of the renal vessels.DISCUSSION: In the renal cortical layer, there was a predominance of indicators of blood flow velocity (BF), blood flow volume (BV), the rate of increase in the density of the contrast agent (CM) in the tissue (MSI), capillary wall permeability (PS) and lower values of the average transit time of the contrast agent (MTT) and the time to reach the maximum contrast agent density in the tissue (TTP) in comparison with the medulla. On the color parametric maps BF, BV, MSI, the cortical layer was characterized by intense red coloring, the medulla — yellow-green, on the TTP map green and blue coloring of the layers was determined, respectively. In elderly patients, there was a decrease in BF, BV with a concomitant lengthening of TTP in the cortical layer without changes in coloring on color parametric maps. On the density-time graph, the kinetic curve of the cortical layer was characterized by the appearance of a peak 10 seconds after the onset of the peak value in the abdominal aorta with further continuation of the curve in the form of a plateau; the kinetic curve of the medulla was characterized by a gradual moderate rise in the curve from 15 seconds after the start of scanning without the formation of peaks values.CONCLUSION: PCT is an informative method for quantitative and qualitative assessment of perfusion in the renal parenchyma.

Medializing Calcaneal Osteotomy for progressive collapsing foot deformity alters the three-dimensional subtalar joint alignment

BackgroundA medializing calcaneal osteotomy (MCO) is considered as one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the post-operative hind- and midfoot alignment, alternations of the subtalar joint alignment remained obscured by superposition on plain radiography. Therefore, we aimed to assess the hind-, midfoot- and subtalar joint alignment pre- compared to post-operatively using 3D weightbearing CT (WBCT) imaging. MethodsSeventeen patients with a mean age of 42 ± 17 years were retrospectively analyzed. Inclusion criteria consisted of PCFD deformity corrected by a medializing calcaneal osteotomy (MCO) as main procedure and imaged by WBCT before and after surgery. Exclusion criteria were patients who had concomitant calcaneal lengthening osteotomies, mid-/hindfoot fusions, hindfoot coalitions, and supramalleolar procedures. Image data were used to generate 3D models and compute the hindfoot (HA), midfoot (MA) - and subtalar joint (STJ) alignment in the coronal, sagittal and axial plane, as well as distance maps. ResultsPre-operative measurements of the HA and MA improved significantly relative to their post-operative equivalents p < 0.05). The post-operative STJ alignment showed significant inversion (2.8° ± 1.7), abduction (1.5° ± 1.8), and dorsiflexion (2.3° ± 1.7) of the talus relative to the calcaneus (p < 0.05) compared to the pre-operative alignment. The displacement between the talus and calcaneus relative to the sinus tarsi increased significantly (0.6 mm±0.5; p < 0.05). ConclusionThis study detected significant changes in the sagittal, coronal, and axial plane alignment of the subtalar joint, which corresponded to a decompression of the sinus tarsi. These findings contribute to our clinical practice by demonstrating the magnitude of alteration in the subtalar joint alignment that can be expected after PCFD correction with MCO as main procedure.

Near-Unity Superradiant Emission from Delocalized Frenkel Excitons in a Two-Dimensional Supramolecular Assembly.

We demonstrate three general effective strategies to mitigate non-radiative losses in the superradiant emission from supramolecular assemblies. We focus on J-aggregates of 5,5',6,6'-tetrachloro-1,1'-diethyl-3,3'-di(4-sulfobutyl)-benzimidazolocarbocyanine (TDBC) and elucidate the nature of their nonradiative processes. We show that self-annealing at room temperature, photo-brightening, and the purification of the dye monomers all lead to substantial increases in emission quantum yields (QYs) and a concomitant lengthening of the emission lifetime, with purification of the monomers having the largest effect. We use structural and optical measurements to support a microscopic model that emphasizes the deleterious effects of a small number of impurity and defect sites that serve as non-radiative recombination centers. This understanding has yielded a room temperature molecular fluorophore in solution with an unprecedented combination of fast emissive lifetime and high QY. We obtain superradiant emission from J-aggregates of TDBC in solution at room temperature with a QY of 82% coupled with an emissive lifetime of 174 ps. This combination of high QY and fast lifetime at room temperature makes supramolecular assemblies of purified TDBC a model system for the study of fundamental superradiance phenomena. High QY J-aggregates are uniquely suited for the development of applications that require high speed and high brightness fluorophores such as devices for high speed optical communication.

Isolated Talonavicular Arthrodesis as Treatment for Flexible Progressive Collapsing Foot Deformity: A Case Series

Category: Hindfoot; Other Introduction/Purpose: Progressive collapsing foot deformity (PCFD) remains a challenging condition for foot and ankle surgeons to treat. While there exists more clarity on the treatment for end-stage rigid deformities involving PCFD, there is still significant debate over different surgical treatment options for the flexible collapsing foot. Common surgical corrections for flexible PCFD include the 'All-American Procedure' popularized by Manoli in the 1990s. Isolated talonavicular (TN) arthrodesis has also been described for the treatment of flexible PCFD. The primary objective of this study was to evaluate clinical and radiographic outcomes in patients with AAFD treated with isolated tri-planar corrective TN arthrodesis. A secondary objective was to establish whether there is a correlation between radiographic outcomes and clinical outcomes. Methods: Fifty-four patients (59 feet) from July 2013 to October 2020 with flexible PCFD underwent surgical treatment with isolated TN arthrodesis. Patients with other arthrodesis or hindfoot osteotomies were excluded. Concomitant gastrocnemius lengthening and toe deformity correction procedures were not an exclusion criterion. Weight-bearing radiographs were performed pre- and postoperatively, with Meary angle (or lateral talo-first metatarsal angle) and calcaneal pitch measured on lateral view. The degree of TN coverage on antero-posterior (AP) radiographs were measured with the TN coverage angle and the degree of first ray angular deformity was measured using Simmon angle (or AP talo-first metatarsal angle). Angles were measured by a foot and ankle fellow. The Foot &amp; Ankle Ability Measure (FAAM) and Veterans-Rand 12 Item Health Survey (VR- 12) were used to clinically evaluate the patient. Results: Thirty-seven females and seventeen males were evaluated with a mean age 61 years at the time of surgery and an average length of follow up of 19 months. There were significant improvements in deformity correction found in this study. Radiographically, the lateral radiographs demonstrated Meary angle correction from 27 degrees pre-operatively to 9 degrees post- operatively (p&lt;0.001) and calcaneal pitch improving from 15 degrees pre-operatively to 18 degrees post operatively (p&lt;.001). AP radiographic analysis demonstrated TN coverage angle improving from 35 degrees pre-operatively to 5 degrees post-operatively (p&lt;0.001) and Simmon angle improving from 20 degrees pre-operatively to 6 degrees, post-operatively (p&lt;.001). The only statistically significant improvement in clinical outcomes was in the FAAM score (pre-operative score 48.48, post-operative score 58.45 (p&lt;.001)). Conclusion: Isolated TN arthrodesis is a viable option for multi-planar deformity correction in patients with flexible PCFD. Not only did it provide significant improvements in radiographic alignment, it also provided improved functional outcomes as demonstrated on FAAM scores. Comparative studies with other surgical treatment techniques such as the 'All-American Procedure' should be performed to determine which is the best technique for patients with flexible PCFD.

Concomitant Achilles Tendon Lengthening with Transmetatarsal Amputation for the Prevention of Late Forefoot Ulceration.

Late development of forefoot ulcers is a common finding after transmetatarsal amputation (TMA). The primary aim of this study was to examine whether concomitant prophylactic Achilles tendon lengthening (ATL) was associated with a reduction in the incidence of forefoot ulcers postoperatively. A retrospective chart review was performed by 2 authors to identify patients who underwent TMA over a period of 5.5 years from January 1, 2015, through July 31, 2020. They identified 110 feet in 107 patients; the 83 patients (85 feet) who had ≥120 days of follow-up were used for the study. Follow-up was performed with telephone calls (80 patients) or during the last office visit (3 patients). Those who were contacted by telephone were asked if they developed an ulcer after healing from the original surgery. Mean follow-up time was 672 ± 258 days for the 30 feet with concomitant Achilles lengthening and 663 ± 434 days for the 55 feet without Achilles lengthening. Demographic data were analyzed for association with late development of forefoot ulceration. Eighty-five feet were included in the analysis. Late forefoot ulcers developed in 35% of feet that had a TMA alone (n = 55) compared with 3% of feet who received a concomitant ATL (n = 30; p < 0.001); the 2 groups had similar mean follow-up times. Mean time to ulcer development was 587 ± 420 days in the 19 patients without Achilles lengthening. Of the patients who developed late forefoot ulcers, 47% also developed osteomyelitis, and 16% went on to proximal amputation. Patients who developed forefoot ulcers were younger (55 ± 12 versus 63 ± 11 years of age; p = 0.006) than those who did not. ATL at the time of TMA is associated with a reduction in the risk of later development of forefoot ulcers, especially in younger patients. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Single session per oral endoscopic myotomy and trans oral incisionless fundoplication – can we prevent reflux in patients with achalasia?

Background and study aims The rate of gastroesophageal reflux disease (GERD) after per oral endoscopic myotomy (POEM) is concerning. Endoscopic anti-reflux methods, such as Trans Oral Incisionless Fundoplication (TIF), are crucial for the long-term success of POEM, especially if they can be performed in the same session. Methods We completed a proof-of-concept canine pilot study (n = 6) to assess safety and feasibility of POEM and TIF in a single session (POEM-TIF). Subsequently, POEM-TIF was also performed in patients with achalasia (n = 5). Herein, we report on the safety, technical and clinical success of the first-in-human cases with symptom follow-up at 1, 3 and 6 months and pH testing at 6 months. Results POEM was completed successfully in six canines (3 anterior and 3 posterior myotomies), followed by TIF in the same session. Necropsy and extensive testing demonstrated no evidence of mucosal injury and no leaks. The reconstructed valve was 220 to 240 degrees, 3 to 4 cm in length, and resulted in concomitant esophageal lengthening (2–5 cm). Using similar principles, the first-in-human cases were performed without intraprocedural or delayed adverse events. pH testing at 6 months showed that four of five patients had no evidence of GERD (DeMeester > 14.72), and in one case, there was evidence of esophagitis. Conclusions Single session POEM-TIF appears to be safe and feasible. Early clinical human data suggests that it may be able to reduce post POEM GERD, however the additional secondary benefits such as lengthening and straightening of the esophagus, may prove to be equally important for the long-term success of POEM.

Intramedullary Antibiotic Depot Does Not Preclude Successful Intramedullary Lengthening or Compression.

The challenging problem of long bone infection and limb length difference cannot be addressed using only an antibiotic-coated nonmagnetic static nail. The combined use of resorbable calcium sulfate and magnetic lengthening nails offers a possible solution to this dilemma, as well as for infected nonunions that require compression. We present a combined technique to treat or prevent infection using femoral or tibial intramedullary antibiotic delivery with an absorbable calcium sulfate depot and concomitant internal lengthening or compression using a nail. Adequate débridement is required in cases of established infection and is a prerequisite for this technique.

Plantar Foot Ulcer Recurrence in Neuropathic Patients Undergoing Percutaneous Tendo-Achilles Lengthening

Equinus contracture carries 3- and 4-fold associations with diabetes and plantar foot ulceration, respectively. Percutaneous tendo-Achilles lengthening is a useful method to alleviate peak plantar pressure resulting from equinus. We aimed to evaluate the effectiveness of percutaneous tendo-Achilles lengthening and estimate the relative longevity of the approach in reducing ulcer recurrence. The medical records of patients with equinus contracture who underwent percutaneous tendo-Achilles lengthening from 2010 to 2017 were reviewed. Included patients presented with plantar ulcers and a gastroc-soleus equinus of any angle <10° of ankle dorsiflexion with the affected knee extended and flexed. Patients who received concomitant tendon lengthening procedures (including anterior tibial tendon or flexor digitorum longus) were excluded. Outcome measures included time to wound healing, time to ulcer recurrence, and development of transfer lesion. Ninety-one patients underwent percutaneous tendo-Achilles lengthening with subsequent pedal ulceration without concomitant procedures. A total of 69 (75.8%) patients had a plantar forefoot ulcer, 7 (7.7%) had midfoot ulcers, 5 (5.5%) had hindfoot ulcers, and 3 (3.3%) had ulcers in multiple locations. Seven patients received prophylactic tendo-Achilles lengthening. At a mean follow-up of 31.6 months (±26), 66 (78.6%) wounds healed at a median 12.9 weeks. A total of 29 patients (43.9%) experienced ulcer recurrence at a mean of 12 months. Twelve patients (13%) experienced a transfer lesion at a mean of 16.6 months. Tendo-Achilles lengthening can be an effective adjunctive approach to achieve wound healing and reduce long-term ulcer recurrence in patients with equinus contracture and neuropathic plantar foot ulcers. A relengthening procedure may be needed within approximately 12 months from index surgery.

Medial Patellofemoral Ligament Reconstruction and Lateral Retinacular Lengthening in the Skeletally Immature Patient

Patellar instability remains a ubiquitous and troublesome problem in orthopaedics and represents a challenge in the pediatric population. Reconstruction of the medial patellofemoral ligament (MPFL) has become a mainstay of patellar instability management in recent years. As with any procedure at or around the physes, there is concern among surgeons regarding safe placement of hardware and drilled tunnels. The authors describe a technique for anatomic MPFL reconstruction with the aid of fluoroscopic guidance to maintain a “safe zone” without violating the distal femoral physis. This technique allows for reliable MPFL reconstruction in the skeletally immature population with concomitant lateral lengthening, while requiring only minor deviations from the procedure in a skeletally mature patient.

Follow-up Study on the Effects of Tendon Transfers and Open Reduction on Moderate Glenohumeral Joint Deformity in Brachial Plexus Birth Injury.

Soft-tissue contractures about the shoulder in patients with brachial plexus birth injury are common and can lead to progressive shoulder displacement and glenohumeral dysplasia. Open or arthroscopic reduction with musculotendinous lengthening and tendon transfers have become the standard of care. The clinical function and radiographic joint remodeling beyond the first 2 years after surgery are not well understood. We performed a follow-up study of 20 patients with preexisting mild to moderate glenohumeral joint deformity who had undergone open glenohumeral joint reduction with latissimus dorsi and teres major tendon transfers and concomitant musculotendinous lengthening of the pectoralis major and/or subscapularis. Prospective collection of Modified Mallet and Active Movement Scale (AMS) scores and radiographic analysis of cross-sectional imaging for glenoid version, humeral head subluxation, and glenohumeral joint deformity classification were analyzed for changes over time. The average duration of radiographic follow-up was 4.2 years (range, 2 to 6 years). The mean glenoid version improved from -31.8° to -15.4° (p < 0.0001). The mean percentage of the humeral head anterior to the middle of the glenoid (PHHA) improved from 9.6% to 30.4% (p < 0.0001). The mean glenohumeral joint deformity score improved from 3.7 to 2.1 (p < 0.0001). All parameters showed the greatest magnitude of improvement between preoperative measurements and 1 year of follow-up. There were no significant changes beyond the 1-year time point in the Mallet scores, AMS scores, or radiographic outcome measures, possibly because of insufficient power, although trends of improvement were noted for some outcomes. No decline in outcome measures was found during the study period. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Excision of distal ulnar exostosis: A case series and literature review

BackgroundMultiple Hereditary Exostoses with distal ulnar exostosis often results in forearm deformity and functional restrictions. Literature reported variable outcomes and frequent complications with an aggressive approach of ulna lengthening. The role of distal ulnar exostosis excision remained uncertain with contradictory effect in restoring growth. Our study aimed to report our outcome of simple excision and compare with the reported results in literature. MethodRetrospective review was carried out in patients with distal ulnar exostoses excision who were operated from 2003 to 2011. Patients with less than 3 years of follow-up, radial head dislocation or subluxation, or within 3 years of skeletal maturity were excluded. Clinical outcome including range of forearm rotation was documented. Radiological outcomes including radial articular angle, carpal slip, ulnar variance and radial bowing were measured. The results were analysed statistically and compared with literature. ResultsFive cases were included in our study. All had excision of exostosis, and one case had additional ulnar lengthening. Mean age of operation was 10.4 years. Mean follow-up time was 72 months. Improvement was shown in the range of pronation, radial articular angle, carpal slip and ulnar variance, in the cases with simple excision alone. Improvements were mostly achieved at the first postoperative year. However, for the case with concomitant lengthening, ulna shortened relatively with growth, and complications were reported. This phenomenon is in keeping with the literature finding. ConclusionSimple excision of distal ulnar exostosis improves forearm rotation and provides some restoration of growth in skeletally immature patients with Masada type I deformity.

δ-Acidity of benzene in [(benzene)RuII(N-N)Cl]+. Crystal structures, nuclear magnetic resonance spectra and nucleus independent chemical shifts

The ligands L1 and L2 are 1:1 condensates of acetylacetone and 2-hydrazinopyridine and 2-hydrazinobenzothiazole respectively. Reactions of these ligands with [RuCl2(C6H6)]2 in 2:1 M proportions in the presence of excess NH4PF6 yield two complexes − dark red [(C6H6)Ru(L1)Cl]PF6 (1) and yellow [(C6H6)Ru(L2)Cl]PF6 (2). Their X-ray crystal structures have been determined. They are 1:1 electrolytes in dimethylsulfoxide (dmso). The bonding in the complexes involves significant back donation from the filled dxy orbital of the metal to the empty π∗ orbital of coordinated benzene, as confirmed by the visualization of the HOMOs in 1 and 2 obtained from the density functional theory (DFT) calculations. As a consequence, in the 1H NMR spectra in dmso-d6 the benzene protons are shifted to lower values of 6.23 (in 1) and 6.37 (in 2) from 7.26 ppm of the free benzene. Thus the protons of the ligated benzene become less deshielded compared to free benzene. Further a concomitant lengthening of the CC bonds in the coordinated benzene by ∼0.04 Å is observed. A pseudo-octahedral geometry of Ru(II) in 1 and 2 is stipulated from a d-d transition which gives the 10 Dq value of 24,500 in 1 and 24,000 cm−1 in 2. The NICS(0) value, an index of aromaticity, calculated at the center of the benzene ring by GIAO method at BP86/LanL2DZ level, of −6.53 ppm in free benzene becomes more negative in 1 (−20.36 ppm) and 2 (−21.45 ppm). Thus coordinated benzene becomes more aromatic from the point of view of NICS. In addition when NICS is varied as a function of the distance (up to 0.8 Å) above the center of the benzene ring, it increases in complexes 1 and 2 whereas in unbound benzene it decreases.

Tracing L-vocalisation in early Scots

This paper provides novel evidence for the frequency and spatio-temporal distribution of the earliest instances of Scots L-vocalisation. This so-called “characteristic Scots change” (McClure 1994: 48) entails the loss of coda-/l/ following back vowels, with concomitant vocalic lengthening or diphthongisation (e.g. OE healf > OSc hawff; OE bolster > OSc bouster; OE full > OSc fow, cf. Johnston 1997: 90). Using data from the Linguistic Atlas of Older Scots (LAOS), spanning 1380-1500, we reassess the claims for the emergence of L-vocalisation in the early 15th century (Aitken & Macafee 2002: 101-4) and for its completion by the beginning of the 16th (cf. Stuart-Smith et al. 2006, Bann & Corbett, 2015). Based on attestations of -less forms and reverse spellings, we map the spread of -loss over time and space. Emphasis is placed on the relative chronologies and lexical and geographic distributions of the change in different phonological contexts, including morpheme-final, pre-labial, pre-velar and (more lexically sporadic) pre-alveolar. Particular attention is also paid to the under-explored /l/~O alternation in borrowed items from (Norman) French (cf. realme~reaume ‘realm’) and their potential influence on the development of coda-/l/ in Scots. The results show low-level presence of the phenomenon throughout our corpus, but no signs of a categorical change in any of the target contexts.

Assessment of different basis sets and DFT functionals for the calculation of structural parameters, vibrational modes and ligand binding energies of Zr4O2(carboxylate)12 clusters

Different basis sets and functionals in the framework of Density Functional Theory (DFT) were assessed for an accurate prediction of structural parameters and vibrational modes of the cluster Zr4O2(methacrylate)12. A basis set of at least triple-ξ quality is necessary to accurately model the geometry and the IR spectra. Bond distances are best reproduced with hybrid functionals, while IR frequencies are best described by the generalized gradient approximation family of functionals. LDA functionals give the highest GGA functionals the lowest ligand binding energies. Increasing the amount of Hartree Fock exchange in the hybrid functionals results in higher binding energies. Binding energies of ligands in different positions of Zr4O2(methacrylate)12 were calculated. The ligand binding energy decreases when the H atoms in an acetate ligand are successively replaced by F atoms with concomitant lengthening of the Zr–O bond. A chelating acetylacetonate ligand shows a higher ligand binding energy than chelating carboxylate ligands.

International multicentre psychometric evaluation of patient-reported outcome data for the treatment of Peyronie's disease.

To compare patient-reported outcomes (PROs) of surgical correction of Peyronie's disease (PD) with the Nesbit procedure, plaque incision and grafting, and the insertion of a malleable penile implant after surgical correction of penile curvature. We performed a retrospective review of men who underwent surgical correction of PD between January 2010 and December 2012 at six international centres. Treatment-related PROs and satisfaction were evaluated with a non-validated questionnaire. The response rate to the questionnaire was 70.9%, resulting in a study cohort of 206 patients. The Nesbit procedure, plaque incision with grafting, or implantation of a malleable penile prosthesis was performed in 50, 48, and 108 patients, respectively. Overall, 79.1% reported a subjective loss of penile length due to PD preoperatively (range 2.1-3.2 cm). Those patients treated with a malleable penile implant reported the greatest subjective penile length loss, due to PD. A subjective loss of penile length of >2.5 cm resulted in reduced preoperative sex ability. Postoperatively, 78.0%, 29.2% and 24.1% patients in the Nesbit, grafting, and implant groups reported a postoperative, subjective loss of penile length (range 0.4-1.2 cm), with 86.3%, 78.6%, and 82.1% of the patients in each group, respectively, being bothered by the loss of length. Penile length loss due to PD affects most patients. Further penile length loss due to the surgical correction leads to bother among the affected patients, irrespective of the magnitude of the loss. The Nesbit procedure was associated with the highest losses in penile length. In patients with PD and severe erectile dysfunction, a concomitant lengthening procedure may be offered to patients to help overcome the psychological burden caused by the loss of penile length.

Alkenyl‐Alkynylgermanes Functionalised by Lewis Acids: Intramolecular Aluminium– and Gallium–Alkyne Interactions and Potential Ge–C Bond Activation

AbstractTreatment of various diethynylgermanes, (R1)2Ge(C≡C–R2)2 (R1 = C6H5, CH3; R1–R1 = C6H4–C6H4; R2 = CH3, CMe3, nBu, C6H5), with equimolar quantities of di(tert‐butyl)aluminium or ‐gallium hydride, R2E–H (E = Al, Ga), afforded mixed alkenyl‐alkynylgermanes, (R1)2Ge(C≡C–R2)[C{E(CMe3)2}=C(H)–R2], by reduction of one of their C≡C triple bonds. The alkenyl groups have a cis arrangement of H and Al or Ga atoms across the C=C double bonds, which reflects the kinetically favoured situation. The cis/trans isomerisation is probably prevented from yielding thermodynamically favoured trans isomers; this is a result of an intramolecular bonding interaction between the α‐carbon atoms of the remaining ethynyl groups and the coordinatively unsaturated metal atoms. The higher Lewis acidity of Al compared to Ga results in relatively short Al···C(ethynyl) contacts (&gt;231.2 pm) and a concomitant lengthening of the Ge–C bonds.

The significance of serum phosphate level on healing index and its relative effects in skeletally immature and mature patients with hypophosphatemic rickets.

The aim of this study was to find out the ideal cut-off level of phosphate for safe healing when deformity correction and concomitant lengthening are indicated in the two different skeletal maturity groups of patients with rickets. Thirty-nine hypophosphatemic rickets patients were selected for the study and were divided into two groups: 27 skeletally immature (group IM) and 12 skeletally mature (group M). The outcomes were evaluated with respect to the healing index (HI), laboratory findings, and complications with the mean follow-up of 5.1 years (range, 3.1–7.9). The healing index (HI) of group IM was 1.44 month/cm and HI of group M was 1.68 month/cm. The negative correlation between the level of serum phosphate and HI in group M (coefficient = −0.94) was evaluated to be less than the correlation in group IM (coefficient = −0.50), indicating that the HI is more likely to be affected by serum phosphate in group M than in group IM. Preoperative serum phosphate levels of 2.3 mg/dL and 2.6 mg/dL were analyzed to be the cut-off values of group IM and group M, respectively, in which the cut-off points divided the series into two groups having the most significantly different HI.

Hydrometallation of amino-trialkynylsilanes--intramolecular M-N interactions (M = Al, Ga) and potential activation of Si-N bonds.

Hydrometallation of a pyrrolidyl functionalised trialkynylsilane, H8C4N-Si(C≡C-CMe3)3, with equimolar quantities of H-M(CMe3)2 (M = Al, Ga) resulted in the formation of mixed alkenyl-dialkynylsilanes (3a, 3b) which have a Lewis-acidic Al or Ga atom in the geminal position to the Si atom and form four-membered M-N-Si-C heterocycles by a strong interaction of the amine N atoms with the Lewis-acidic metal atoms. This interaction results in a concomitant lengthening and weakening of the Si-N bonds. Dual hydrometallation afforded alkynyl-dialkenylsilanes (4a, 4b) with two Lewis-acidic metal atoms. Al-N and Ga-N interactions to one of the Lewis-acidic centres led again to the formation of M-N-Si-C heterocycles. The second Al atom of 4a interacted with C-H bonds of the vinylic tert-butyl group, while the Ga atom of 4b was coordinated to the α-C atom of the remaining alkynyl substituent. Dual hydrometallation of the corresponding pyrrolyl-trialkynylsilane resulted in compounds with different structures (5a, 5b) due to the delocalisation of the lone pair of electrons at nitrogen in the aromatic ring. One metal atom is coordinated to the α-C atom of the alkynyl group, and the other has close contact to a C-H bond of the pyrrole ring. The synthesis of 4b gave an unprecedented bicyclic by-product (6) which has a Ga-H-Ga 3c-2e bond. It was formally formed by hydrogallation of the trialkyne with the sesquihydride [H2Ga-CMe3]2[H-Ga(CMe3)2]2 and was also obtained by the selective reaction with this starting material.

A study of the proarrhythmogenic effect of acute left ventricular afterload increase: insights from a novel closed chest/pericardium model

Purpose: To determine whether acute LV afterload increase is an additive risk factor in sudden cardiac death. Prior studies of mechano-electric coupling during acute afterloading were limited to open chest/pericardium preparations or ex vivo models. The aim of this study was to determine the interrelationships of an acute LV afterload challenge with the induction, presence and disappearance of delayed after depolarizations (DADs). Methods: Systolic blood pressure was raised by 30% during 5 to 10 beats by acute balloon inflation (2-3ml) in the mid-descending aorta. Echo guidance was used to position a contact electrode catheter to record monophasic action potentials (MAPs). Concomitant 12 lead ECG was recorded. Endocardial MAP registration was performed during 30 pressure challenges in 3 consecutive pigs. Results: In all cases MAP duration and MAP amplitude slightly decreased during the acute pressure challenge (242±6 to 237±6 ms, p<0.001 ; 21.8±0.9 to 21.3±0.8 mV, p<0.05) with a concomitant lengthening of the RR interval (521±9ms to 570±13ms, p<0.001). With balloon release these changes normalized over several beats. Moreover, acute afterloading caused beat-to-beat appearance of DADs during 16/30 pressure challenges (figure A, asterisks). In 10/30 these DADs caused premature ventricular complexes (PVCs) (figure B) and in 1/30 short non-sustained ventricular tachycardia. Conclusion: The feasibility of MAP registration in a near to physiological closed chest/pericardium model of acute LV pressure overload was demonstrated. Furthermore, a beat-to-beat development of DADs was demonstrated during acute pressure overload giving rise to PVCs, with immediate disappearance during pressure release.

Spectroscopic Studies of the Mononuclear Non-Heme FeII Enzyme FIH: Second-Sphere Contributions to Reactivity

Factor inhibiting hypoxia-inducible factor (FIH) is an α-ketoglutarate (αKG)-dependent enzyme which catalyzes hydroxylation of residue Asn803 in the C-terminal transactivation domain (CAD) of hypoxia-inducible factor 1α (HIF-1α) and plays an important role in cellular oxygen sensing and hypoxic response. Circular dichroism (CD), magnetic circular dichroism (MCD), and variable-temperature, variable-field (VTVH) MCD spectroscopies are used to determine the geometric and electronic structures of FIH in its (Fe(II)), (Fe(II)/αKG), and (Fe(II)/αKG/CAD) forms. (Fe(II))FIH and (Fe(II)/αKG)FIH are found to be six-coordinate (6C), whereas (Fe(II)/αKG/CAD)FIH is found to be a 5C/6C mixture. Thus, FIH follows the general mechanistic strategy of non-heme Fe(II) enzymes. Modeling shows that, when Arg238 of FIH is removed, the facial triad carboxylate binds to Fe(II) in a bidentate mode with concomitant lengthening of the Fe(II)/αKG carbonyl bond, which would inhibit the O2 reaction. Correlations over α-keto acid-dependent enzymes and with the extradiol dioxygenases show that members of these families (where both the electron source and O2 bind to Fe(II)) have a second-sphere residue H-bonding to the terminal oxygen of the carboxylate, which stays monodentate. Alternatively, structures of the pterin-dependent and Rieske dioxygenases, which do not have substrate binding to Fe(II), lack H-bonds to the carboxylate and thus allow its bidentate coordination which would direct O2 reactivity. Finally, vis-UV MCD spectra show an unusually high-energy Fe(II) → αKG π* metal-to-ligand charge transfer transition in (Fe(II)/αKG)FIH which is red-shifted upon CAD binding. This red shift indicates formation of H-bonds to the αKG that lower the energy of its carbonyl LUMO, activating it for nucleophilic attack by the Fe-O2 intermediate formed along the reaction coordinate.