A quantitative assessment of the functional recovery of flexion of the elbow after nerve transfer in patients with a brachial plexus injury.

AIMS: Improvements in the evaluation of outcome after nerve transfers are required. The assessment of force using the Medical Research Council (MRC) grades (0 to 5) is not suitable for this purpose. A ceiling effect is encountered within MRC grade 4/5 rendering this tool insensitive. Our aim was to show how the strength of flexion of the elbow could be assessed in patients who have undergone a re-innervation procedure using a continuous measurement scale. METHODS: A total of 26 patients, 23 men and three women, with a mean age of 37.3 years (16 to 66), at the time of presentation, attended for review from a cohort of 52 patients who had undergone surgery to restore flexion of the elbow after a brachial plexus injury and were included in this retrospective study. The mean follow-up after nerve transfer was 56 months (28 to 101, standard deviation (sd) 20.79). The strength of flexion of the elbow was measured in a standard outpatient environment with a static dynamometer. RESULTS: In total, 21 patients (81%) gained MRC grade 4 strength of flexion of the elbow. The mean force of flexion was 7.2 kgf (3 to 15.5, sd 3.3). CONCLUSION: This study establishes that the dynamometer may be used for assessing the strength of flexion of the elbow in the outpatient department after nerve reconstructive surgery. Cite this article: Bone Joint J 2016;98-B:1517-20.

Mycolactone-mediated neurite degeneration and functional effects in cultured human and rat DRG neurons: Mechanisms underlying hypoalgesia in Buruli ulcer.

BACKGROUND: Mycolactone is a polyketide toxin secreted by the mycobacterium Mycobacterium ulcerans, responsible for the extensive hypoalgesic skin lesions characteristic of patients with Buruli ulcer. A recent pre-clinical study proposed that mycolactone may produce analgesia via activation of the angiotensin II type 2 receptor (AT2R). In contrast, AT2R antagonist EMA401 has shown analgesic efficacy in animal models and clinical trials for neuropathic pain. We therefore investigated the morphological and functional effects of mycolactone in cultured human and rat dorsal root ganglia (DRG) neurons and the role of AT2R using EMA401. Primary sensory neurons were prepared from avulsed cervical human DRG and rat DRG; 24 h after plating, neurons were incubated for 24 to 96 h with synthetic mycolactone A/B, followed by immunostaining with antibodies to PGP9.5, Gap43, ß tubulin, or Mitotracker dye staining. Acute functional effects were examined by measuring capsaicin responses with calcium imaging in DRG neuronal cultures treated with mycolactone. RESULTS: Morphological effects: Mycolactone-treated cultures showed dramatically reduced numbers of surviving neurons and non-neuronal cells, reduced Gap43 and ß tubulin expression, degenerating neurites and reduced cell body diameter, compared with controls. Dose-related reduction of neurite length was observed in mycolactone-treated cultures. Mitochondria were distributed throughout the length of neurites and soma of control neurons, but clustered in the neurites and soma of mycolactone-treated neurons. Functional effects: Mycolactone-treated human and rat DRG neurons showed dose-related inhibition of capsaicin responses, which were reversed by calcineurin inhibitor cyclosporine and phosphodiesterase inhibitor 3-isobutyl-1-Methylxanthine, indicating involvement of cAMP/ATP reduction. The morphological and functional effects of mycolactone were not altered by Angiotensin II or AT2R antagonist EMA401. CONCLUSION: Mycolactone induces toxic effects in DRG neurons, leading to impaired nociceptor function, neurite degeneration, and cell death, resembling the cutaneous hypoalgesia and nerve damage in individuals with M. Ulcerans infection.

Nerve injuries associated with supracondylar fractures of the humerus in children: our experience in a specialist peripheral nerve injury unit.

AIMS: We aimed to identify the pattern of nerve injury associated with paediatric supracondylar fractures of the humerus. PATIENTS AND METHODS: Over a 17 year period, between 1996 and 2012, 166 children were referred to our specialist peripheral nerve injury unit. From examination of the medical records and radiographs were recorded the nature of the fracture, associated vascular and neurological injury, treatment provided and clinical course. RESULTS: Of the 166 patients (111 male, 55 female; mean age at time of injury was seven years (standard deviation 2.2)), 26 (15.7%) had neurological dysfunction in two or more nerves. The injury pattern in the 196 affected nerves showed that the most commonly affected nerve was the ulnar nerve (43.4%), followed by the median (36.7%) and radial (19.9%) nerves. A non-degenerative injury was seen in 27.5%, whilst 67.9% were degenerative in nature. Surgical exploration of the nerves was undertaken in 94 (56.6%) children. The mean follow-up time was 12.8 months and 156 (94%) patients had an excellent or good clinical outcome according to the grading of Birch, Bonney and Parry. CONCLUSION: Following paediatric supracondylar fractures we recommend prompt referral to a specialist unit in the presence of complete nerve palsy, a positive Tinel's sign, neuropathic pain or vascular compromise, for consideration of nerve exploration. TAKE HOME MESSAGE: When managed appropriately, nerve recovery and clinical outcomes for this paediatric population are extremely favourable. Cite this article: Bone Joint J 2016;98-B:851-6.

Paediatric hand fractures.

This retrospective study reviews the demographics, morphology and management of paediatric hand fractures. Notes of all children with hand injuries attending a plastic surgery paediatric trauma clinic over a one-year period were reviewed. Non-bony injuries were excluded. A total of 303 fractures in 283 patients were included. Fracture incidence rose after the age of seven, peaking at 14 years of age; 76% of fractures occurred in males. Sporting injuries accounted for 47% of fractures. Physeal fractures were present in 39% of cases. Open fractures accounted for only 4% of all fractures. Management was primarily conservative. Only 5% of cases required surgical fixation; 6% of patients experienced complications.

Isolated scaphoid fracture with anterosuperior dislocation of the proximal fragment.

Isolated fracture of the scaphoid with an associated anterosuperior dislocation of the proximal fragment is an extremely rare injury. We present two cases where open reduction and internal fixation through a palmar and dorsal approach was performed. No instances of non-union, necrosis of the proximal fragment of the scaphoid or scapholunate dissociation were noted during a mean follow-up period of 18 months. Clinical results (active motion, power grip, DASH) following such injury and intervention are presented. The aetiology of this rare injury is discussed.

The MD-medical doctorate or mandatory doctorate?

The introduction in the UK of the Calman Registrar training scheme envisaged seamless progression from Senior House Officer (SHO) grade through to Consultancy. Within this framework research was acknowledged to be a valuable (but optional) part of the training programme, as laid out by the 'Orange Guide' to Specialist Registrar (SpR) Training [A Guide to Specialist Registrar Training 1998; HM Press]. Time is provided for this activity within the SpR training scheme, but it is becoming increasingly evident that the majority of formal research (towards post graduate degrees) is being carried out by so-called 'gap' SHO's in order to gain entry into Higher Surgical Training (HST) programmes [Ann R Coll Surg Engng 81 (1999) 182], [Br J Plast Surg 55 (2002) 463-468]. With this in mind, a survey of all Plastic Surgery SHO's in the UK was undertaken to assess the extent of clinical research undertaken by individuals, and the perceived need for formal research for career progression.

Functional outcomes following surgical repair of wrist extensor tendons.

The long term results following the repair of open injuries to extensors carpi radialis longus and brevis and extensor carpi ulnaris have not previously been reported. A retrospective case note review was performed and patients were called back for assessment following surgical repair. Grip strength and pinch strength were reduced by 9.9% (p=0.017) and 11.5% (p=0.049). Wrist movement was also reduced. This demonstrates that the division of these tendons should not be regarded as trivial as they may have long-term adverse effects on wrist function. Information gained from this study may be beneficial in patient education at the time of injury and may provide useful information when preparing medico legal reports.

Genetic and physical characterization of proBA genes of the marine bacterium Vibrio parahaemolyticus.

Intracellular proline pools have been implicated in the halotolerance of many organisms. To examine this relationship in a moderately halotolerant marine bacterium, Vibrio parahaemolyticus, proline biosynthesis genes were cloned in various plasmids. Some genetic and structural properties of those genes were examined. Subcloning showed that about 3.1 kilobases of V. parahaemolyticus DNA could complement proA and proB but not proC mutations of Escherichia coli. The same fragment would also complement some Pro- mutants of V. parahaemolyticus. Gamma-delta insertion mutagenesis of this subcloned fragment indicated that proB and proA genes of V. parahaemolyticus might be transcribed from different promoters. Two other genes, phoE and gpt, which map closely to the proBA genes in E. coli, were also found to be in close proximity to the proBA genes of V. parahaemolyticus.

Salt tolerance of lactose-grown Vibrio parahaemolyticus carrying Escherichia coli lac genes.

Lac- strains of Vibrio parahaemolyticus were converted to Lac+ on receiving a hybrid plasmid containing the lactose utilization genes of Escherichia coli K-12. A V. parahaemolyticus strain containing this hybrid plasmid exhibited optimal growth rates on glucose and other carbon sources in the presence of 0.2 to 0.4 M NaCl. Growth of the same strain on lactose was inhibited at similar concentrations of NaCl. The altered growth rate responses in lactose medium appeared to be attributable to effects of NaCl on the activity of lactose permease, and possibly on that of beta-galactosidase, rather than on the levels of these enzymes in V. parahaemolyticus cells.

Shuttle cloning vectors for the marine bacterium Vibrio parahaemolyticus.

Two cosmid cloning vectors containing lambda cos sequences and a 42-base-pair multipurpose cloning sequence were constructed. pAD22 also contains a 1.4-kilobase TRP-ARS fragment from Saccharomyces cerevisiae. These cosmids transformed Escherichia coli and S. cerevisiae cells and could be mobilized into Vibrio parahaemolyticus strains with a conjugative plasmid, pRK2013. The cosmid pAD22 was genetically and structurally stable during passage through V. parahaemolyticus and E. coli strains.

Photorepair of ultraviolet-induced petite mutational damage in Saccharomyces cerevisiae requires the product of the PHR1 gene.

A wild-type (phr+) diploid yeast strain showed photorepair of petite mutational damage, whereas a photoreactivation-deficient (phr1/phr1) diploid strain did not, indicating that the PHR1 gene product was required for mitochondrial photorepair.

The Pasteur effect and catabolite repression in an oxidative yeast, Kluyveromyces lactis.

The presence of the Pasteur effect in Kluyveromyces lactis grown in glucose was shown by azide-stimulated glucose fermentation. Extracts from these cells contained ATP-sensitive phosphofructokinase activity. Cells grown on succinate oxidized glucose slowly at first without azide-stimulated rates of fermentation. Phosphofructokinase in these cells was ATP-insensitive. The activity of NAD+-isocitrate dehydrogenase in cell extracts did not require AMP activation. These results suggested the presence of a Pasteur effect in glucose-grown but not in succinate-grown K. lactis, mediated by (a) ATP inhibition of phosphofructokinase (b) possibly via feedback control of glucose transport, but not by AMP activation of isocitrate dehydrogenase. Azide inhibition of the Pasteur effect during growth of the cells did not lead to catabolite repression of respiratory activity. The results therefore suggest that the Pasteur effect does not inhibit the development of a Crabtree effect in oxidative yeasts.

The absence of DNA photoreactivation enzyme in yeast mitochondria.

Mitochondria isolated from haploid yeast cells by spheroplast lysis were purified by flotation on renografin gradients. Electron micrographs and respiratory control ratios revealed that the purified mitochondria were still intact and functional. Assays for photoreactivation enzyme using as substrate [3H]-thymine-labeled Escherichia coli DNA were performed on crude and purified mitochondrial preparations. While the crude preparation contained high amounts of photoreactivation enzyme, it appeared to be associated with contaminating nuclei. The purified mitochondria lacked any photoreactivation enzyme activity. We suggest that yeast mitochondria do not normally contain photoreactivation enzyme.

Evidence for an inducible glucose transport system in Kluyveromyces lactis.

To find the cause of delayed glucose oxidation in succinate-grown Kluyveromyces lactis, glucose transport was studied in glucose- and in succinate-grown cells. The initial rate of 2-deoxyglucose (2-dGlc) accumulation, as well as the appearance of 2-deoxyglucose 6-phosphate, was higher in the glucose-grown cells. In both cell types, 2-dGlc was apparently transported in the free form to be phosphorylated intracellularly. In glucose-grown cells the level of free 2-dGlc in the pool was always less than the external concentration. Exchange transport in starved, poisoned cells loaded with unlabeled 2-dGlc was 140-fold greater in glucose- than in succinate-grown cells, probably beacuse of the presence of an inducible transport component. The development of the increased rate of transport in a succinate-grown uracil-requiring auxotroph after transfer to glucose depends on the presence of uracil.