[Rejuvenate, it's as old as the hills ]. / Rajeunir, c'est vieux comme le monde .

Legends and myths regarding eternal youth exist since Antiquity. Prior to the 19th century those wishing to rejuvenate used baths or blood injections, searching to the Fountain of Youth or calling for an alchemist claiming to have found the Elixir of Youth. In the 19th century, Charles Edouard Brown Séquard (1819-1894), after the discovery of the function of the endocrinal glands and testicular secretions, inject himself with an extract from guinea pigs and dogs. He found himself rejuvenated! In the beginning of the 20th century, several surgeons transplanted human testicles coming from death row prisoners inmates or voluntary donors. The transplantation of monkey testicles by Serge Voronoff (1866-1951) had a important aftermath and more than 300 similar interventions took place. The simple ligation of the vas deferens (vasectomy) was recommended by Eugen Steinach (1866-1944). Sigmund Freud was one of the "beneficiaries". Steinach also advised the irradiation of the ovaries for female rejuvenation. In 1935, Alexis Carrel (1873-1944) and Charles Lindbergh (1902-1974) built a pump to feed and regenerate targeted organs. The discovery of pluripotent stem cells and senolytic molecules are building up new hopes on the matter.

The C-terminus of amelogenin enhances osteogenic differentiation of human cementoblast lineage cells.

BACKGROUND AND OBJECTIVES: Amelogenin proteins are the major constituent of developing extracellular enamel matrix and are believed to have an exclusively epithelial origin. Recent studies have suggested that amelogenins might induce the differentiation and maturation of various cells, including cementoblast lineage cells. However, the residues comprising the active site of amelogenin remain unclear. The purpose of this study was to identify the active site region of amelogenin by studying the effects of amelogenin fragments on the osteogenic differentiation of cementoblasts. MATERIAL AND METHODS: Amelogenin fragments lacking the C-terminus (rh163) and N-terminus (rh128) and a fragment consisting of the C-terminal region of rh174 (C11 peptide) were synthesized and purified. Human cementoblast lineage cells were cultured in osteogenic differentiation medium and treated with 0, 10, 100 or 1000 ng/mL of rh163, rh128 or C11 peptide. The mRNA levels of bone markers were examined by real-time polymerase chain reaction analysis. Alkaline phosphatase activity and calcium deposition were also determined. Mineralization was evaluated by alizarin red staining. RESULTS: The osteogenic differentiation of human cementoblast lineage cells was significantly enhanced by treatment with rh128 or C11 peptide, whereas rh163 had no significant effect as compared with untreated controls. CONCLUSIONS: The C-terminus of amelogenin promotes the osteogenic differentiation of human cementoblast lineage cells, indicating the possible utility of C11 peptide in periodontal tissue regeneration.

Treatment of unstable proximal interphalangeal joint fractures with hemi-hamate osteochondral autografts.

The primary aim of this study was to assess the clinical and radiological results after hemi-hamate resurfacing arthroplasty in patients with acute or chronic unstable fractures of the base of the middle phalanx and to describe technical features that can facilitate the surgical procedure. Hemi-hamate arthroplasties were done in 19 patients (mean age 39 years) with an isolated fracture at the base of the middle phalanx that involved more than 40% of the articular surface. We assessed ten chronic cases (treated >6 weeks after fracture) and nine acute ones (<6 weeks) at a mean of 24 months. Pain scores, QuickDASH scores, grip strengths, range of motion and radiological findings were recorded at follow-up. At follow-up, the mean active flexion at the proximal interphalangeal joint was to 83° with a mean fixed flexion of 17° (active range of motion 66°). The mean active distal interphalangeal motion was 41°. The mean visual analogue scale score was 1.1. The mean QuickDASH score was 11. The mean pinch strength was 82% of the opposite side. Radiographs revealed one partial graft lysis. LEVEL OF EVIDENCE: IV.

Ulnar nerve transposition using a mini-invasive approach: case series of 30 patients.

The treatment of ulnar nerve compression at the elbow remains controversial. No single technique has yet proven its superiority. We describe a technique combining the advantages of the mini-invasive approach with those of transposition. We present the results of 30 patients, of mean age 52 years, who underwent anterior subcutaneous transposition of the ulnar nerve using a mini-invasive approach with a follow-up of more than six months. The incision measures 3 cm. The results were evaluated by measuring pain intensity, quick disabilities of the arm shoulder and hand (DASH), grip strength and pinch, and McGowan score, pre- and post-operatively. All parameters were improved post-operative. The mean pain score went from 5.5 to 4, the quick DASH from 48 to 38, mean grip strength from 28 to 31 kg, and mean pinch strength from 4.7 to 6.4 kg. The McGowan score was also improved; pre-operatively, there were 16 patients at stage III, seven patients stage II, seven patients stage I, and post-operatively there was one patient stage III, three patients stage II, 16 patients stage I, and 10 patients stage 0. Analysis of our series shows that a 3 cm incision without endoscopy allows subcutanous transposition, with results at least as good as those with other techniques. The advantages of our technique are that it is easy, has a limited approach, preserves blood supply, allows placement of the nerve in a favourable environment, and decreases nerve stretching during elbow flexion.

Successful thumb reconstruction after tumor resection by immediate toe transfer in a 67-year-old patient: case report and literature review.

Age is a limiting factor for microsurgery. We report the case of a 67-year-old patient with a malignant tumor on the right thumb, treated by amputation and immediate reconstruction by partial transfer of the hallux, with an excellent result, but venous swelling at the fourth day that required a controlled bleeding for 3 days. In the light of this observation, we think that there is no age limit for reconstruction of a thumb by toe transfer, either cosmetically or functionally.

Photosynthetic performance of invasive Pinus ponderosa and Juniperus virginiana seedlings under gradual soil water depletion.

Changes in climate, land management and fire regime have contributed to woody species expansion into grasslands and savannas worldwide. In the USA, Pinus ponderosa P.&C. Lawson and Juniperus virginiana L. are expanding into semiarid grasslands of Nebraska and other regions of the Great Plains. We examined P. ponderosa and J. virginiana seedling response to soil water content, one of the most important limiting factors in semiarid grasslands, to provide insight into their success in the region. Photosynthesis, stomatal conductance, maximum photochemical efficiency of PSII, maximum carboxylation velocity, maximum rate of electron transport, stomatal limitation to photosynthesis, water potential, root-to-shoot ratio, and needle nitrogen content were followed under gradual soil water depletion for 40 days. J. virginiana maintained lower L(s), higher A, g(s), and initial F(v)/F(m), and displayed a more gradual decline in V(cmax) and J(max) with increasing water deficit compared to P. ponderosa. J. virginiana also invested more in roots relative to shoots compared to P. ponderosa. F(v)/F(m) showed high PSII resistance to dehydration in both species. Photoinhibition was observed at approximately 30% of field capacity. Soil water content was a better predictor of A and g(s) than Psi, indicating that there are other growth factors controlling physiological processes under increased water stress. The two species followed different strategies to succeed in semiarid grasslands. P. ponderosa seedlings behaved like a drought-avoidant species with strong stomatal control, while J. virginiana was more of a drought-tolerant species, maintaining physiological activity at lower soil water content. Differences between the studied species and the ecological implications are discussed.

[Michel Latarjet (1913-1999), surgeon explorer!]. / Michel Latarjet (1913-1999), chirurgien explorateur !

In 1954, Michel Latarjet, anatomist and surgeon of Lyon, developed an original surgical technique to treat the unstable shoulder . This technique since kept his name: "Latarjet". He was a character in 1000 facets: highly skilled anatomist, skillful surgeon, talented sportsman, accomplished musician, big traveler, and many others... An eclectic life, symbol of an abundant XXth century.