Effects of Aromaticity in Cations and Their Functional Groups on the Low-Frequency Spectra and Physical Properties of Ionic Liquids.

We have critically investigated the low-frequency spectra of six ionic liquids (ILs) consisting of systematically different cations having benzyl moieties or comparable-sized saturated cyclohexylmethyl groups, by means of femtosecond Raman-induced Kerr effect spectroscopy (fs-RIKES). The target ionic liquids are bis(trifluoromethylsulfonyl)amide ([NTf2](-)) salts of the 1-benzyl-3-methylimidazolium ([BzMIm](+)), 1-benzyl-1-methylpyrrolidinium ([BzMPyrr](+)), 1-benzylpyridinium ([BzPy](+)), 1-cyclohexylmethyl-3-methylimidazolium ([CHxmMIm](+)), 1-cyclohexylmethyl-1-methylpyrrolidinium ([CHxmMPyrr](+)), and 1-cyclohexylmethylpyridinium ([CHxmPy](+)) cations. The primary purpose of this study is to clarify the effects of charged and neutral aromatic moieties on the low-frequency spectrum and bulk properties such as liquid density, surface tension, shear viscosity, glass transition temperature, and melting point. We found that ILs with benzyl groups have larger surface tensions than those with the same cation bearing the cyclohexylmethyl group. The trend in the glass transition temperatures, comparing ILs having the same side group, is pyridinium > imidazolium > pyrrolidinium. The effects of a single aromatic moiety on the shear viscosity are inconclusive, although the viscosities of the ILs with aromatic moieties on both the cation and the benzyl group, i.e., [BzMIm][NTf2] and [BzPy][NTf2], are substantially lower than those of the other ILs at room temperature, as a consequence of their higher fragilities. In the low-frequency Kerr spectra in the frequency range of approximately 0.1 to 200 cm(-1) measured by fs-RIKES, the ILs possessing two aromatic groups show the largest relative intensity of the nuclear response to the electronic response. Both the charged and neutral aromatic rings show signals due to the ring libration; the neutral one appears at a lower frequency than the charged one. The relationship between the first moment of the broad low-frequency spectrum band and the bulk parameter consisting of the square root of the surface tension divided by the liquid density is obeyed by the cyclohexylmethyl derivatives whether the cation is aromatic or not, but not by the ILs with the neutral aromatic benzyl group. Quantum chemistry calculations have been also performed to understand the vibrational modes of the ionic species in the ILs.

Secondary surgeries after digital replantations: a case series.

We evaluated the injuries, survival rats, and secondary surgeries of patients who had undergone finger replantation or revascularization between October 2005 and July 2010. The 70 digits came from 43 patients (average age, 46 years; range, 19 to 78 years; 37 men). Overall replantation survival rate was 94%; 93% (27/29) for complete amputations and 95% (39/41) for near-amputations. In all, 39 digits from 21 patients required 48 secondary surgeries; skin grafts, tenolysis, joint fusion, bone graft, osteotomy, and web plasty. The more proximal or more severe the injuries, the higher the need of secondary surgeries. The most common surgery soon after replantation was skin coverage; the most common after two months was tendon surgery. Primary repair must be adequate to restore the function and appearance of amputated digits; however, the possible need for secondary surgeries must be kept in mind to avoid restricting the options for secondary procedures.

Preventing postoperative congestion in reverse pedicle digital island flaps when reconstructing composite tissue defects in the fingertip: a patient series.

For reconstructing an injured fingertip, a reverse pedicle digital island flap can restore excellent function and appearance. However, postoperative flap congestion may lead to flap necrosis. We tested a method for dissecting the vascular pedicle to prevent congestion and to provide more reliable results. Between August 2002 and December 2010, we reconstructed 14 fingertips in 13 patients (average age, 43 years; range, 24 to 68 years; 9 men). Through a small zigzag incision, the digital artery and a 4-mm-wide subcutaneous venous network were elevated in retrograde fashion to facilitate venous drainage. All flaps healed completely without severe congestion or necrosis. Slight flexion contractures remained in the PIP (mean, 12°) and DIP (mean, 14°) joints. Our procedure is simpler and more reliable than other techniques, such as adding a narrow skin bridge to the pedicle or a venous anastomosis to prevent venous congestion, and it assures the survival of the flap.

Rhenium-catalyzed regio- and stereoselective addition of two carbon units to terminal alkynes via carbon-carbon bond cleavage of ß-keto sulfones.

Treatment of ß-keto sulfones with terminal alkynes gave unsaturated δ-keto sulfones in good to excellent yields under rhenium catalysis. In this reaction, the insertion of the alkynes into the nonstrained carbon-carbon single bond between the α- and ß-positions of the ß-keto sulfones proceeded smoothly, and (Z)-isomers were produced with high regio- and stereoselectivities.

Diploid endosperm formation in Tulipa spp. and identification of a 1:1 maternal-to-paternal genome ratio in endosperms of T. gesneriana L.

Most Liliaceae plants have the tetrasporic Fritillaria-type embryo sac and normally form diploid embryos and pentaploid endosperms derived from a 4:1 maternal-to-paternal genome ratio (4m:1p) after double fertilization. Here we characterize embryo sac and endosperm formation in Tulipa spp. of Liliaceae. Chromosome analysis using seeds derived from 2x x 2x crosses of Tulipa gesneriana (2n = 2x = 24) identified diploid chromosome number in the endosperm. Similarly, flow cytometric analysis confirmed diploid endosperm formation in T. gesneriana, T. fosteriana (2n = 2x = 24) and T. greigii (2n = 2x = 24). To further study the possible mechanism of diploid endosperm formation, we made interploidy crosses of triploid (2n = 3x = 36) x diploid in which aneuploid seeds with various chromosome numbers (2n = 25-36) were produced. Again, flow cytometric analysis confirmed the same ploidy level in both embryos and endosperms at all aneuploidy levels, suggesting that only a single haploid polar nucleus contributes to endosperm formation at fertilization. Histological observation further confirmed the physical separation of two polar nuclei by a large vacuole in the Fritillaria-type embryo sac of T. gesneriana that appeared to prevent the fusion of the two polar nuclei that originated at the micropylar and chalazal ends before fertilization. Taken together, these results indicate that diploid endosperms (1m:1p) are normally formed in Tulipa spp. by fusion of the micropylar polar nucleus (n) and a spermatid (n) but not by normal triple fusion. We also show that tulip endosperm partially overcomes the triploid block mechanism that occurs in interploidy crosses. Based on these observations, the possible role of triple nuclear fusion in double fertilization is discussed.

A Blauth IIIB hypoplastic thumb reconstructed with a vascularised metatarso-phalangeal joint transfer: a case report with 28 years of follow up.

We reconstructed the Blauth-IIIB hypoplastic right thumb of a 16-year-old girl with a vascularised metatarso-phalangeal (MTP) joint from her second toe combined with a dorsalis-pedis flap. Abduction was provided with an abductor policis long tendon advancement, and adduction, with an extensor indicis proprius tendon transfer. Opponoplasty was performed one year later using the flexor sublimis (IV) tendon. The transferred joint remained functional and non-osteoarthritic 28 years later. Radial and palmar abduction of the reconstructed thumb was 45 degrees and 75 degrees respectively. The index, middle, and ring fingers could oppose the thumb, however she grasped small objects between her index and middle fingertips. If a pollicisation using the index finger is not accepted, the reconstruction described here is one of the surgical options. However donor-foot morbidity is not negligible. Currently, we use a proximal-interphalangeal joint transfer with an opponoplasty using an abductor digiti minimi as a first choice, when planning a reconstruction of preserved hypoplasic thumb.

Predicting functional recovery and return to work after mutilating hand injuries: usefulness of Campbell's Hand Injury Severity Score.

PURPOSE: We investigated the effect of severity and form of mutilating hand injuries on functional recovery and return to work, and the usefulness of an injury-severity score in predicting these outcomes. METHODS: We reexamined patients in whom finger amputation or near amputation had been treated with replantation or revascularization at our institution at least 3 years earlier. We evaluated radiographs, sensory recovery, finger range of motion, skin temperature, and current overall hand function to calculate Tamai and Quick Disabilities of the Arm, Shoulder, and Hand scores, and recorded return-to-work status, duration of treatment, and time away from work. We determined injury level, number of involved fingers, type of injury, and Campbell's Hand Injury Severity score (HISS) from the medical record. RESULTS: The average age of the 50 enrolled patients was 43 years (range, 18-69 years); average follow-up was 7.8 years (range, 3.1-15.3 years). More proximal injuries, more involved fingers, and more complicated injury predicted poorer functional recovery. HISS was highly correlated with Tamai's score (r = -0.77; p<.001) and moderately correlated with the Quick Disabilities of the Arm, Shoulder, and Hand score (r = 0.39; p = .009). HISS was only moderately correlated with length of treatment (r = 0.32; p<.05) and with time away from work (r = 0.34; p<.05). Mean HISS among the 3 return-to-work groups differed remarkably. When HISS was <50, 11 of 12 patients returned to their original jobs; when it was between 50 and 150, 17 of 23 patients were able to return; and when it was >150, only 4 of 15 were able to return to work. CONCLUSIONS: Given the current surgical care of patients with mutilated hand injuries, HISS determined at the time of injury can adequately predict functional outcome and return to work status. Larger studies will be necessary to validate these findings.

Effect of suture material and bone quality on the mechanical properties of zone I flexor tendon-bone reattachment with bone anchors.

PURPOSE: To compare the initial biomechanical properties of zone I flexor tendon to bone repairs performed using pull-out and anchor techniques and to investigate the effect of bone quality and suture materials on the strength of anchor repairs. METHODS: Using computed tomography, we measured bone mineral density and cortical thickness of the distal phalanx of 60 cadaver fingers (mean age, 77 years). Flexor digitorum profundus tendons were then transected at their insertion sites and repaired using a 4-strand grasping suture and either pull-out or anchor fixation. For pull-out repair (n = 20), the suture strands (Supramid 3-0; S. Jackson, Inc., Alexandria, VA) were passed through the distal phalanx and tied over a dorsal button. For anchor repair, 2 bone anchors were inserted into the distal phalanx, and tendons were grasped using either Supramid (n = 21), Ethibond (Ethicon, Inc., Somerville, NJ; n = 10), or FiberWire suture (Arthrex Inc., Naples, FL; n = 9) (all 3-0). Mechanical properties of the repaired tendon-bone constructs were determined in linear, load-to-failure loading and correlated with bone characteristics. RESULTS: The FiberWire-anchor repair group had the best combination of mechanical properties, with ultimate force to failure no different from the pull-out repairs but with greater stiffness and reduced displacement. Pull-out suture repairs had significantly higher ultimate force-to-failure values than did Ethibond-anchor and Supramid-anchor repairs (p < .01). However, pull-out repairs had significantly reduced stiffness and greater displacement at 20 N force than did anchor repairs from all groups (p < .05). Both bone mineral density and cortical thickness correlated significantly with ultimate force (p < .01). Almost all anchors pulled out for bone mineral density below 420 mg/cm(3) or cortical thickness less than 0.31 mm, which occurred only for specimens aged greater than 75 years. CONCLUSIONS: The mechanical properties of the double Mitek bone anchors were sensitive to both suture material and bone quality. FiberWire-anchor repairs provided the best combination of mechanical properties. Pull-out suture repairs had good strength but poor stiffness. Anchor fixation may be contraindicated in patients greater than 75 years because of poor bone quality.

Damaging fatigue loading stimulates increases in periosteal vascularity at sites of bone formation in the rat ulna.

Bone formation in a variety of contexts depends on angiogenesis; however, there are few reports of the vascular response to osteogenic skeletal loading. We used the rat forelimb compression model to characterize vascular changes after fatigue loading. The right forelimbs of 72 adult rats were loaded cyclically in vivo to one of four displacement levels, to produce four discrete levels of ulnar damage. Rats were killed 3-14 days after loading, and their vasculature was perfused with silicone rubber. Transverse histological sections were cut along the ulnar diaphysis. We quantified vessel number, average vessel area, total vessel area, and bone area. On day 3, we observed a dramatic periosteal expansion near the ulnar midshaft, with significant increases in periosteal vascularity; total vessel area was increased 250-450% (P < 0.001). Vascularity remained elevated on days 7 and 14. Vessel number and average vessel area were not correlated (P = 0.09) and contributed independently to total vascular increases. Bone area was not increased on day 3 but on days 7 and 14 was increased significantly in all displacement groups (P < 0.01) due to periosteal woven bone formation. Vascular and bone changes depended on longitudinal location (P < 0.001), with peak increases 2 mm distal to the midshaft. Vascular and bone changes also depended on displacement level (P < 0.005), with greater increases at higher levels of fatigue displacement. We conclude that skeletal fatigue loading induces a rapid increase in periosteal vascularity, followed by an increase in bone area. The angiogenic-osteogenic response is spatially coordinated and scaled to the level of the mechanical stimulus.

Alendronate prevents bone loss and improves tendon-to-bone repair strength in a canine model.

Previously we showed a loss of bone and a concomitant decrease in mechanical properties in the first 21 days after flexor tendon insertion site injury and repair in a canine model. The goal of this short-term study was to suppress bone loss after insertion site repair using alendronate in an attempt to prevent the reduction in biomechanical properties. Flexor tendons of the second and fifth digits of the right forelimbs of canines were injured and repaired. Dogs received a daily oral dose of alendronate (2 mg/kg). One digit in each dog also received a local dose of alendronate in the bone tunnel at the time of surgery. The repair was evaluated for bone mineral density (BMD) and biomechanical properties and compared to data from a previous study in which no alendronate was used. Alendronate was effective in protecting the distal phalanx from resorption during tendon-to-bone healing (BMD was 94 and 104% of control for systemic alendronate and for systemic plus local alendronate, respectively). Alendronate treatment prevented much of the decrease in ultimate load that occurs in the first 21 days. Without treatment, ultimate load was 42% of control. With systemic alendronate treatment and systemic plus local alendronate treatment, ultimate load was 78 and 69% of control, respectively. Failure mode was significantly different when comparing alendronate treatment to repair alone. A lower incidence of suture pull through was found in alendronate treated dogs, suggesting less tendon degeneration. Ultimate load can be improved in association with preventing the bone loss that normally occurs during the early period following tendon-to-bone repair. These initial short-term data demonstrate the potential for a clinical treatment that could enhance tendon-to-bone healing.

Early healing of flexor tendon insertion site injuries: Tunnel repair is mechanically and histologically inferior to surface repair in a canine model.

Orthopedic injuries often require surgical reattachment of tendon to bone. Tendon ends can be sutured to bone by direct apposition to the bone surface or by placement within a bone tunnel. Our objective was to compare early healing of a traditional surface versus a novel tunnel method for repair of the flexor digitorum profundus (FDP) tendon insertion site in a canine model. A total of 70 tendon-bone specimens were analyzed 0, 5, 10 or 21 days after injury and repair, using tensile and range of motion mechanical testing, histology and densitometry. Ultimate force (a measure of repair strength) did not differ between surface and tunnel repairs at day 0. Both repair types had reduced strength at 10 and 21 days compared to 0 days, indicative of deterioration of suture grasping strength (tendon softening). At 21 days, tendons repaired in a bone tunnel had 38% lower ultimate force compared to surface repairs (p = 0.017). Histological findings were comparable between repair groups at 5 and 10 days but differed at 21 days, when we saw evidence of maturation of the tendon-bone interface in the surface repairs compared to an immature fibrous interface with no evidence of tendon-bone integration in the tunnel repairs. After accounting for bone removed by the tunnel, no difference in bone mineral density or trabecular bone volume existed between surface and tunnel repairs. If the results of our animal study extend to healing of the human FDP insertion, they indicate that FDP tendons should be reattached to the distal phalanx by suture to the cortical surface rather than suture in a bone tunnel.

Functional and cosmetic results of fingertip replantation: anastomosing only the digital artery.

In fingertip amputations, conventional stump plasty provides an almost acceptable functional result. However, replanting fingertips can preserve the nail and minimize loss of function. We investigated the functional and cosmetic results of fingertip replantation at the terminal branch of the digital artery. Outcomes were nailbed width and distal-segment length; sensory recovery; and range of motion (ROM) of thumb-interphalangeal (IP) or finger-distal interphalangeal (DIP) joints, and total active motion (TAM) of the replanted finger. Of 15 fingertips replanted after only arterial anastomosis, 13 were successful, and 12 were studied. After a median of 1.3 years, mean nailbed widths and distal-segment lengths were 95.4% and 93.0%, respectively, of the contralateral finger. Average TAM and ROM of the thumb-IP or finger-DIP joints were 92.0% and 83.0% of normal, respectively. Semmes-Weinstein results were blue (3.22 to 3.61) in 4 fingers and purple (3.84 to 4.31) in 8; the mean result from the 2-point discrimination test was 5.9 mm (range, 3 to 11 mm). Thus, amputated fingertips should be aggressively replanted.

Long-term clinical and neurologic recovery in the hand after surgery for severe cubital tunnel syndrome.

PURPOSE: Functional outcomes of cubital tunnel surgery may decline as the severity of preoperative ulnar neuropathy increases. When functional recovery will be adequate, or whether tendon transfers should be required, may be unclear. We investigated the extent of functional recovery, the duration of the recovery process, and the necessity of restoring intrinsic muscle function in patients with severe cubital tunnel syndrome after surgery. METHODS: We retrospectively studied outcomes after cubital tunnel release in 15 patients with marked intrinsic muscle atrophy, claw-hand deformity, immeasurable (electrically silent) sensory and motor nerve conduction velocities, and Semmes-Weinstein test (SWT) results ranging from purple (3.84-4.31) to red (4.56-6.65). We evaluated subjective (numbness and activities of daily living [ADL] disturbances), objective (manual muscle testing [MMT] of index-finger abduction, and SWT), and neurophysiologic (nerve conduction velocity) outcomes. Overall functional outcome was evaluated by Akahori's criteria. RESULTS: At a median follow-up evaluation of 4.5 years all outcomes had improved. Numbness was gone in 5 patients and greatly reduced in 9 patients; 6 patients reported slight difficulties in ADLs; and 9 patients had no difficulties. Motor nerve conduction velocity was measurable (mean, 35.3 m/s) in all 15 patients and sensory nerve conduction velocity was measurable (mean, 43.4 m/s) in 12. Recoveries in nerve conduction velocities persisted beyond 2 years. The SWT results were blue (3.22-3.61) in 6 patients, purple (3.84-4.31) in 8 patients, and red (4.56-6.65) in 1 patient. MMT of index finger abduction was grade 4 or 5 in 11 of 15 patients. Half the patients over 70 years old, however, were grade 3 or less. Akahori's criteria were excellent in 3 patients, good in 6 patients, and fair in 6 patients. CONCLUSIONS: Patients with severe intrinsic muscle atrophy and absent motor and sensory nerve conduction velocities can expect satisfactory long-term functional results after surgery. Function continues to improve beyond 2 years. Restoring index finger abduction is not always necessary for ADLs, although recovery requires several years and is poorer in the elderly.

Distal nerve elongation vs nerve grafting in repairing segmental nerve defects in rabbits.

Segmental nerve defects have been repaired with nerve grafts. However, regenerating fibers must go through two coaptation sites, and donor site morbidities are inevitable. We elongated the distal nerve segment using a tissue expander and reconnected the nerve. We compared these results with those of nerve grafting. Nerve injury models were created in the median nerves of both forelimbs in 27 rabbits. The right nerve was repaired by elongation, and the left by tibial nerve grafting. The length of the elongation was the same as that of the graft in each animal. Eight rabbits had a 10-mm segment repaired, 9 had a 15-mm segment repaired, and 10 had a 20-mm segment repaired. Evaluated outcomes were nerve conduction velocity, contractile force of the flexor muscle, axons number, and fiber diameter. The elongated and grafted groups did not differ substantially on any outcome. Distal nerve elongation could be an alternative to nerve grafting for repairing large nerve defects.

Proximal nerve elongation vs nerve grafting in repairing segmental nerve defects in rabbits.

If segmental nerve defects could be repaired by elongating the proximal or distal segments, nerve grafting might be unnecessary. We elongated a 40-mm proximal segment of an injured median nerve, in the rabbit right forelimb, at a rate of 1 mm/day for 10 days in 10 rabbits and for 15 days in another 10. On the left forelimb of the same rabbits, a 10- for 15-mm segment of the median nerve was removed, and a 10- for 15-mm segment, respectively, of the tibial nerve was grafted in its place. Four months after the initial surgery, nerve conduction velocity (NCV), contractile strength of the flexor digitorum superficialis (FDS), axon count, and axon diameter did not differ significantly between the 10-mm groups but were better in the 15-mm grafted group. Elongating the proximal nerve segment may be an alternative to grafting in repairing segmental defects of less than 10 mm.