Halogen- and hydrogen-bonded self-assembled fibrillar networks of substituted 1,3:2,4-dibenzylidene-D-sorbitols (DBS)

Substituting the sole primary hydroxyl group of the low molecular weight organogelator (LMOG), 1,3:2,4-dibenzylidene-D-sorbitol (DBS), with a halogen atom (Cl, Br, or I; i.e., 6-Cl-DBS, 6-Br-DBS, or 6-I-DBS) drastically alters the supramolecular self-assembled fibrillar network (SAFiN) that forms when the molecules aggregate. The SAFiN varies depending on the solvent properties, impacting the role of non-covalent hydrogen- and halogen-bonding interactions along and between fibers. The halogenated DBS derivatives have more coherent crystalline fibers than DBS, with larger length-to-width aspect ratios. High-resolution synchrotron powder X-ray diffraction of each wet-state gel in toluene and DFT optimization obtained complete structures for the three halogenated DBS derivatives in their SAFiNs. The presence of a halogen atom reduces the reliance on hydrogen bonding by enabling new halogen bonding interactions that impact the self-assembly behavior, especially in solvents of higher polarity. For 6-I-DBS and 6-Br-DBS, the primary forces driving molecular self-assembly are C-H⋯π and intermolecular halogen-to-halogen interactions, and there is one unique molecule in each unit cell. However, the Cl atoms of 6-Cl-DBS are not close, and its SAFiN structures rely more on hydrogen bonding. As a result, the enhanced hydrogen bonding, electronic differences among the halogens, and spatial factors allow its unit cell to include two independent molecules of 6-Cl-DBS.

Comparison of static and dynamic in vitro digestibility and bioaccessibility of palm-based emulsions and correlation to a human study: effects of triacylglycerol crystallinity

The static and dynamic TIM-1 in vitro digestibility of similarly sized Span 60 o/w emulsions containing either liquid palm olein droplets (PO) or palm stearin (PS) droplets tempered to contain different levels of crystallinity (i.e., PS-SE (maximum), PS-SE-INT (intermediate), and PS-LE (undercooled)) were explored. Static in vitro digestion experiments included particle size analysis, and emulsion digestibility and bioaccessibility were compared between the static and dynamic models, respectively. β-carotene (BC, 0.1 wt%) was also incorporated in the emulsions to determine the influence of triacylglycerol (TAG) crystallinity on BC bioaccessibility and stability during storage under accelerated lighting conditions. TAG crystallinity altered the colloidal fat crystal network properties and ultimately impacted lipid digestion, attenuating early static in vitro lipolysis for the PS emulsions compared to the PO emulsion. This correlated well with TIM-1 bioaccessibility trends and with results from our results of a previous human study wherein the rise in postprandial TAG was delayed when healthy men consumed PS-SE versus PS-LE. The presence of crystalline TAG modestly accelerated BC degradation, and did not improve preservation nor alter BC in vitro bioaccessibility.

605 Group and Save Sampling in Total Knee and Hip Arthroplasty: Is It Necessary?

Aim

To induce a change in practice with regard to pre-op G&S sampling. This is common practice in elective orthopaedics. Transfusion rates are negligible. Therefore, omitting this practice can reduce the financial burden on the Trust.

Method

Patient's undergoing elective primary total knee or hip arthroplasty over a 1-year period were retrieved from a database. Data regarding pre/post-op haemoglobin levels and transfusion status was obtained from patient case notes and Trust ICE pathology reporting system.

Results

There were a total of 454 patient's (251 undergoing TKR, 203 undergoing THR). Four patient's (1.6%) in the TKR group and 11 patient's (5.4%) in the THR group required transfusion. Of these patient's, 5 had cardiac problems and 6 had pre-operative anaemia.

Conclusions

Routine G&S sampling is unnecessary in the majority of cases and should only be reserved for certain cases (patient's with significant cardiac problems and those with a transfusion history). Patient's with pre-operative anaemia should have optimisation of haemoglobin level prior to the procedure.

Functional outcomes of conservatively managed acute ruptures of the Achilles tendon

AIMS

This prospective cohort study aims to determine if the size of the tendon gap following acute rupture of the Achilles tendon shows an association with the functional outcome following non-operative treatment.

PATIENTS AND METHODS

All patients presenting within two weeks of an acute unilateral rupture of the Achilles tendon between July 2012 and July 2015 were considered for the study. In total, 38 patients (nine female, 29 male, mean age 52 years; 29 to 78) completed the study. Dynamic ultrasound examination was performed to confirm the diagnosis and measure the gap between ruptured tendon ends. Outcome was assessed using dynamometric testing of plantarflexion and the Achilles tendon Total Rupture score (ATRS) six months after the completion of a rehabilitation programme.

RESULTS

Patients with a gap ≥ 10 mm with the ankle in the neutral position had significantly greater peak torque deficit than those with gaps < 10 mm (mean 23.3%; 7% to 52% vs 14.3%; 0% to 47%, p = 0.023). However, there was no difference in ATRS between the two groups (mean score 87.2; 74 to 100 vs 87.4; 68 to 97, p = 0.467). There was no significant correlation between gap size and torque deficit (τ = 0.103), suggesting a non-linear relationship. There was also no significant correlation between ATRS and peak torque deficit (τ = -0.305).

CONCLUSION

This is the first study to identify an association between tendon gap and functional outcome in acute rupture of the Achilles tendon. We have identified 10 mm as a gap size at which deficits in plantarflexion strength become significantly greater, however, the precise relationship between gap size and plantarflexion strength remains unclear. Large, multicentre studies will be needed to clarify this relationship and identify population subgroups in whom deficits in peak torque are reflected in patient-reported outcome measures. Cite this article: Bone Joint J 2017;99-B:87-93.

Ultrasonographic findings after Achilles tenotomy during Ponseti treatment for clubfeet: Is ultrasound a reliable tool to assess tendon healing?

INTRODUCTION

Several studies have claimed ultrasound to be useful and accurate in assessing the healing phase of Achilles tendons after tenotomy during Ponseti treatment for clubfoot deformity. The purpose of our study was to assess the healing process of Achilles tendons ultrasonographically after tenotomy as part of Ponseti clubfoot management and to assess the effects of previously not considered ultrasound properties (anisotropy, partial volume effect), and whether these practical considerations affect accurate measurements which have been claimed possible in previous studies.

MATERIALS AND METHODS

We monitored the post-tenotomy healing process in 15 patients (22 tendons) using high frequency ultrasound for a minimum of six months (range 6-14 months). The scanning was discontinued once a tendon looked normal or when the appearance remained unchanged between scans. We also studied nine patients (11 tendons) who had undergone Achilles tenotomies up to seven years previously (range 34-83 months).

RESULTS

In the immediate postoperative period, ultrasound showed large variations in the distance of the tenotomy from the calcaneum as well as the obliquity and completeness of the surgical division. We encountered pitfalls in the use of ultrasound to define healing stages that were not described previously. Sonography was inaccurate and subjective in assessing both completeness of the surgical division and tendon measurements. Despite ultrasonographically proven incomplete tendon division in 63 % of cases, the clinical effect of an immediate increase of passive foot dorsiflexion from the pretenotomy position with an obvious palpable tendon gap was achieved in all patients. At the end of the study, 65 % of tendons did not achieve a normal appearance.

CONCLUSIONS

We do not think that routine ultrasound studies are of any value as an adjunct to clinical assessment intra- and post-operatively. It can give misleading information regarding the need to complete the tenotomy, which may increase risks associated with a further pass of the scalpel blade.

Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk

OBJECTIVE

Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis.

METHODS

34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis.

RESULTS

28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II-IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000.

CONCLUSION

These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients.

ADVANCES IN KNOWLEDGE

The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis.