Lumbrical Muscles Neural Branching Patterns: A Cadaveric Study With Potential Clinical Implications.

BACKGROUND: Lumbrical muscles originate in the palm from the 4 tendons of the flexor digitorum profundus and course distally along the radial side of the corresponding metacarpophalangeal joints, in front of the deep transverse metacarpal ligament. The first and second lumbrical muscles are typically innervated by the median nerve, and third and fourth by the ulnar nerve. A plethora of lumbrical muscle variants has been described, ranging from muscles' absence to reduction in their number or presence of accessory slips. The current cadaveric study highlights typical and variable neural supply of lumbrical muscles. MATERIALS: Eight (3 right and 5 left) fresh frozen cadaveric hands of 3 males and 5 females of unknown age were dissected. From the palmar wrist crease, the median and ulnar nerve followed distally to their terminal branches. The ulnar nerve deep branch was dissected and lumbrical muscle innervation patterns were noted. RESULTS: The frequency of typical innervations of lumbrical muscles is confirmed. The second lumbrical nerve had a double composition from both the median and ulnar nerves, in 12.5% of the hands. The thickest branch (1.38 mm) originated from the ulnar nerve and supplied the third lumbrical muscle, and the thinnest one (0.67 mm) from the ulnar nerve and supplied the fourth lumbrical muscle. In 54.5%, lumbrical nerve bifurcation was identified. CONCLUSION: The complex innervation pattern and the peculiar anatomy of branching to different thirds of the muscle bellies are pointed out. These findings are important in dealing with complex and deep injuries in the palmar region, including transmetacarpal amputations.

The Propeller Myocutaneous Flap of the Upper Eyelid: Anatomical Study and its Clinical Implication.

BACKGROUND: The reconstruction of the upper eyelid and the periorbital region is a challenge for the surgeon. The aims of this reconstruction are to guarantee protection to the eyeball, maintain the visual field, and restore the function of the eyelid without damaging other anatomical structures. In this study, the authors describe the use of a propeller myocutaneous flap based on the small vertical branches of marginal, peripheral ed superficial arcade, for the reconstruction of the upper eyelid or periorbital region. MATERIALS AND METHODS: The authors enrolled 3 patients (Caucasian), between 2018 and 2019, and subjected to reconstructive surgery with the propeller myocutaneous flap of the periorbital region at the Plastic Surgery Unit of the University of Messina. The vascularization of the flap was demonstrated through an anatomical study conducted on cadavers at the dissection laboratories of the University of Bordeaux 2. RESULTS: The authors have shown that the myocutaneous flap represents a valid alternative for loss of substance coverage and reconstruction of the upper eyelid or periorbital region, allowing the achievement of a good aesthetic and functional result. FOLLOW UP: Patients were followed up at 3-6-12 months. No complications were reported (flap retraction, periocular region deformity, donor site morbidity). Furthermore, at the last visit, the scars were almost invisible. CONCLUSIONS: The use of the propeller myocutaneous flap of the upper eyelid is a valid reconstructive alternative to the standard techniques described so far for the reconstruction of the periorbital region.

The Use of a Hypoallergenic Dermal Matrix for Wrapping in Peripheral Nerve Lesions Regeneration: Functional and Quantitative Morphological Analysis in an Experimental Animal Model.

INTRODUCTION: The aim of this research was to test, in an animal model, the nerve regeneration technique with a hypoallergenic acellular dermal matrix used to wrap the microsurgical neural suture. MATERIALS AND METHODS: Two groups of rats received the cut of limb right median nerves. The regeneration technique considers for both groups an end-to-end nerve suture. In the experimental group (A) was used also a wrapping protocol by a conduit of collagen matrix currently used in oral surgery. The animals underwent functional grasping tests (at 1, 3, 5, and 7 months) and a histological and quantitative analysis of distal nerve was performed at the end of experimental time. RESULT: After seven months, the grasping test reveals functional recovery in each tested animal; this improvement is more evident in Group A. The fibers appear well organized with restored myelin sheaths in both groups. Group A showed a great quantity of connective tissue surrounding the nerve. The quantitative morphology analysis in both groups shows a similar fibers density, fiber diameter, and myelin thickness. The differences between the groups in axon mean diameter are significant. In Group A M/d, D/d, and g-ratio is significantly higher compared to control group. CONCLUSIONS: Histological and functional assessments show a functional recovery of the injured nerve in the test groups, stressed by the results of the grasping tests and the meaningful increasing in fiber diameter and higher g-ratio. Moreover, a connective tissue cuff distinguishes the distal portion of the injured nerve. Considering the easy availability and handling of the material used in this study we can conclude that this experimental technique can be considered as a valid alternative to protect nerves in nerve wrap surgery.

Anterolateral Thigh Flap in a Chicken Model: A Novel Perforator Training Model.

BACKGROUND: Preclinical training in perforator flap harvesting is typically conducted on living animal models; however, repeated training is not possible with these models because of ethical and/or economical constraints. We describe an anterolateral thigh flap (ALT flap) training model using chicken thigh that seems to be an appropriate training model prior, for example, to raise a perforator flap in a living rat or swine model. METHODS: A total of 10 chicken legs were used in this study. Six chicken legs were anatomically dissected to confirm the presence of the perforator and to identify the main vascular tree. In four chicken legs, a skin flap was planned based on the perforator and intramuscular dissection was performed under magnification. RESULTS: The perforator was identified in all dissections and was consistently found 3 cm above the line extending from the patella to the head of the femur in its third proximal. Proximally, the mean diameter of the artery and vein was 0.56 (σ = 0.04) and 0.84 (σ = 0.06) mm, respectively. The mean dissection time to raise the flap was 88 (σ = 7) min. CONCLUSION: This is the first description of a nonliving biological simulation model for training in perforator flap dissection that mimics an ALT flap. As an ex vivo chicken model, it is a cost effective and readily accessible model suitable for repeated practice.

Novel mutations of dystrophin gene in DMD patients detected by rapid scanning in biplex exons DHPLC analysis.

Mutations in the dystrophin gene result in both Duchenne and Becher muscular dystrophies (DMD and BMD). Approximately 65% of all mutations causing DMD are deletions (60%) or duplications (5%) of large segments of this gene, spanning one exon or more. Due to the large size of the dystrophin gene (79 exons), finding point mutations has been prohibitively expensive and laborious. Recent studies confirm the utility of pre-screening methods, as denaturing high-performance liquid chromatography (DHPLC) analysis in the identification of point mutations in the dystrophin gene, with an increment of mutation detection rate from 65% to more than 92%. Here we suggest an alternative and convenient method of DHPLC analysis in order to find mutations in a more rapid and less expensive way by introducing the analysis of 16 couples of dystrophin amplicons, in biplex exons DHPLC runs. Using this new protocol of biplex exons DHPLC screening, new mutations were identified in four male patients affected by DMD who had tested negative for large DNA rearrangements.

Antiproliferative activity of melatonin by transcriptional inhibition of cyclin D1 expression: a molecular basis for melatonin-induced oncostatic effects.

Melatonin is endowed with a growth inhibitory effect in MCF-7 breast cancer cells whose mechanism has been related to an antiestrogenic activity exerted by inhibition of binding of the estradiol-estrogen receptor complex to its DNA responsive element. Looking for downstream gene determinants of this effect, we performed a transcriptome profiling by high-density microarrays of estrogen-treated MCF-7 cells exposed or not to melatonin. We found that cyclin D1 was one of the main downregulated genes by melatonin. Validation experiments clearly confirm that in MCF-7 cells the estrogen-induced growth inhibitory activity of melatonin is consistently associated with inhibition of estrogen-elicited cyclin D1 induction. This effect is almost purely transcriptional. Reporter gene assays indicate that the same portion of the cyclin D1 promoter which confers estrogen sensitivity, encompassing a potential cAMP responsive element binding site, is repressed by melatonin. Transcriptional downregulation of cyclin D1 is the key molecular event for melatonin's antiproliferative activity, as this activity can be completely and selectively rescued by transient cyclin D1 overexpression. Finally, we provide indirect evidence that the effect of melatonin on the cyclin D1 promoter is mediated by the c-jun and ATF-2 proteins, known to bind the minimal estrogen-sensitive cyclin D1 promoter element. These findings establish for the first time a molecular link between melatonin and its effects on the cell cycle, providing at the same time a rationale for its use in adjuvant chemotherapy.