Hydration of human nails investigated by NIR-FT-Raman spectroscopy.

The human nail, although it is usually stable against outer influences, becomes soft and flexible after soaking in water. Frequent washing increases brittleness of nails. Hydration of nails is thought to be the most important factor influencing the physical properties of nails and possibly acts through changes in keratin structure. Here NIR-FT-Raman has been used to examine molecular structural changes of intact moisten nails. Raman spectra were obtained both in vitro from nail samples and in vivo before and after soaking in water. The water uptake of normal nail samples during the first 15 min was reflected in the increasing intensity ratio of the nu(OH)/nu(CH(2)) bands. A saturating effect appeared soon after 10 min which is explained by a defined water holding capacity. R(nu) representation of the low frequency range of the Raman spectra showed that mainly bound water is found both in dry and in wet nails. This implies water-protein interaction. Protein backbone vibration at 932 cm(-1) indicating alpha-helical proteins increased in intensity in the wet nails. The nu(S-S) which is sensitive to changes in conformation of proteins showed a 4% higher intensity. Additional protein-water interactions could lead to a slight change of the dihedral angle of the C-S-S-C bonds and to geometric changes in coiling behavior of the alpha-helical protein. Suggesting a separation between matrix proteins and fiber proteins giving them a greater freedom of flexibility. The in vivo spectra detected from the distal part of the nail resembled spectra in vitro. Raman spectra of the proximal part of the nail showed that it was fully saturated with water. The proximal part of the nail did not show changes in water content and protein structure during nail moisturizing in the Raman spectra. Our results suggest that the softening of the nail following hydration may be due to changed matrix protein molecular structure induced by water.     

Delayed primary reconstruction of subtotal nail bed loss using a split-thickness nail bed graft on decorticated bone

Split-thickness nail bed grafting is the accepted method of treatment for injuries involving loss of nail bed tissue. The nail bed of the great toe may be used without donor-site morbidity, and nail bed grafting may be combined with other procedures for fingertip reconstruction. A case of fingertip avulsion injury with loss of the nail plate, nail bed, and periosteum over the exposed distal phalanx of the thumb was reconstructed by a split-thickness nail bed graft placed directly on granulating decorticated bone. The length, appearance, and function of the injured dominant thumb were preserved.     

Yellow-nail syndrome: report of three cases.

The yellow nail syndrome, a combination of yellow discolouration of and dystrophic changes in the nails, pleural effusions and lymphedema, is thought to be relatively rare; to date 44 cases have been reported. Of a further three patients with this syndrome, one had all three features, one had the yellow nails alone and the other had pleural effusions and lymphedema without classic nail changes. Each had recurrent lower respiratory tract infections; and of all 47, chronic pulmonary infections occurred in approximately one quarter and were frequently associated with chronic sinus infections. The underlying abnormality is presumed to be a congenital defect of the lymphatics, but so far this has not been demonstrated to be the cause of the nail changes, the pathogenesis of which remains obscure.     

A search for longitudinal variations in trace element levels in nails of Alzheimer’s disease patients

Levels of Br, Hg, K, and Zn were determined by INAA in the nails of Alzheimer’s disease (AD) patients at 6-mo intervals for up to 3 yr. These elements have been shown to be imbalanced in AD nail. Bromine showed no trends. Mercury tended to decrease in nail with increasing age of patient, and with the duration and severity of the dementia. Potassium and Zn tended to increase with these came factors. Hence, progressive changes in trace-element levels do occur in AD nail, although imbalances are detected even in the earliest sampled stages of the disease.     

Congenital curved nail of the fourth toe

Five cases of congenital curved nail of the fourth toe are reported. Patients included four males and one female; four cases were bilateral, and one was unilateral. There were no other significant associated anomalies of the extremities, and only the fourth toes were affected. The features of the deformity are a curved nail and hypoplasia of the soft tissue and bone of the distal phalanx of the fourth toe. This anomaly may be transmitted autosomally and is unique in that it may be of mesodermic origin.     

Human nail stem cells are retained but hypofunctional during aging

The nail is a continuous skin appendage. Cells located around the nails, which display coordinated homeostatic dynamics and release a flow of stem cells in response to regeneration, have been identified in mice. However, very few studies regarding human nail stem cells exist in the literature. Using specimens isolated from humans, we detected an unreported population of cells within the basal layer of postnatal human nail proximal folds (NPFs) and the nail matrix around the nail root. These cells were multi-expressing and expressed stem cell markers, such as keratin 15 (K15), keratin 14 (K14), keratin 19 (K19), CD29, CD34, and leucine-rich repeat-containing G protein-coupled receptor 6 (Lgr6). These cells were very similar to mouse nail stem cells in terms of cell marker expression and their location within the nail. We also found that the putative nail stem cells maintained their abundance with advancing age, but cell proliferation and nail growth rate were decreased on comparison of young and aged specimens. To summarize, we found a putative population of stem cells in postnatal human nails located at NPFs and the nail matrix. These cells may have potential for cell differentiation and be capable of responding to injury, and were retained, but may be hypofunctional during aging.     

Titanium,Sinusitis, and the Yellow Nail Syndrome

Yellow nail syndrome is characterized by nail changes, respiratory disorders, and lymphedema. In a yellow nail patient with a skeletal titanium implant and with gold in her teeth, we found high levels of titanium in nail clippings. This study aims to examine the possible role of titanium in the genesis of the yellow nail syndrome. Nail clippings from patients with one or more features of the yellow nail syndrome were analyzed by energy dispersive X-ray fluorescence. Titanium was regularly found in finger nails in patients but not in control subjects. Visible nail changes were present in only half of the patients. Sinusitis with postnasal drip and cough was the most common complaint. The dominant source of titanium ions was titanium implants in the teeth or elsewhere. The titanium ions were released through the galvanic action of dental gold or amalgam or through the oxidative action of fluorides. In other patients the titanium was derived from titanium dioxide in drugs and confectionary. Stopping galvanic release of titanium ions or canceling exposure to titanium dioxide led to recovery. In one patient with a titanium implant, the symptoms recurred after renewed exposure to titanium. Yellow nail syndrome is caused by titanium     

Loads acting in an intramedullary nail during fracture healing in the human femur.

The form and function of the musculo-skeletal system is closely related to the forces acting in its components. Significant forces are present in the long bones, but their magnitudes have so far only been estimated from mathematical models. Fracture fixation by means of metal implants provides an opportunity to measure the implant-born forces and to estimate the long bone forces before healing occurs. The load changes during fracture healing may provide additional information. Therefore, a telemetrized, interlocking femoral nail for wireless transmission of forces and moments acting across the fracture site was developed. The design was based on the geometry and material of a 16 mm AO nail with a circular, closed cross-section allowing full protection of the electronic circuits from the body fluids. After careful testing, it was implanted in a 33-year-old patient who had sustained a multifragmentary fracture of the left femur. Measurements at a rate of approx. 0.4 Hz were performed in different patient postures between the 2nd and 26th postoperative week. Significant axial forces and bending moments were measured during several activities such as sitting, unsupported leg elevation and partial weight bearing in a standing position. Forces orthogonal to the nail axis remained small. The reductions of the implant loads due to fracture consolidation were in the order of 50%. Dynamization of the nail did not change the forces. Even though the telemetry system did not allow for dynamic measurements and the results presented here provide data from one subject only, the new information will be useful with respect to implant design, biomechanics of fracture fixation and evaluation of healing progression.     

“INGROWN” NAILS AND OTHER TOENAIL PROBLEMS—Surgical Treatment

Appropriate office treatment for “ingrown” or deformed toenails can bring quick and lasting relief. The principle is the removal of the portion of the nail that irritates. For mild problems, a buried nail corner or spur may be successfully trimmed away without anesthesia. More extensive infection requires a nerve block anesthetic of the toe and removal of a wide triangle of deformity with nail edge and the mass of heaped up granulations.Chronic or recurrent infection is often associated with some abnormality of the nail. It usually saves time and suffering in the long run to remove a third or so of the width of the nail together with its matrix or “root.” Sharp dissection is relatively easy and far more dependable than other methods of removal or destruction of the matrix. The matrix of the entire nail can be removed just as easily to eliminate such problems as the grossly thickened nail of onychogryphosis.     

The Use of Snail Gut Cytase in Fluorescent Banding Studies on Plant Chromosomes

The fluorescent bands produced in chromosomes by quinacrine derivatives, although highly acid-labile, have been shown to be resistant to digestion by snail gut cytase. This enzyme may therefore be used to soften plant root-tips and so facilitate the production of flat, unbroken mitotic-metaphase plates for fluorescent-banding studies. The roots are fixed in 3:1 absolute alcohol:glacial acetic acid then thoroughly washed in water. The washed roots are then dipped in undiluted cytase and digested for either 2 hrs at room temperature or overnight in a domestic refrigerator. Next they are squashed on a slide and stained in 0.5% aqueous quinacrine hydrochloride for 10-15 minutes at pH 6.2. After washing in three changes of water they are mounted in water. The coverslips are sealed on with clear nail varnish.     

Fingernail deformities secondary to ganglions of the distal interphalangeal joint (mucous cysts)

Twenty-six nail deformities secondary to ganglions of the distal interphalangeal joint were retrospectively reviewed to assess the important aspects of their management. The patients' ages ranged from 41 to 79 years. The long and index fingers were most commonly involved. A depression or groove was present in 23 of 26 digits reviewed. Two had gross disruption of the nail. Fifty-eight percent of the cysts had spontaneously drained or had been drained by the patient or a physician preoperatively. Degenerative arthritic changes were seen in 87 percent of those with x-rays or a radiology report available. Most underwent surgical removal of the cyst and debridement of associated osteophytes of the distal interphalangeal joint. The cyst was located above the germinal matrix in all but two digits. Osteophytes were found in all 20 digits in which the joint was explored. No recurrences were seen in those available for postoperative follow-up (22 of 25). Normal nail growth was found in 14 of 22, although follow-up was short in one. All eight postoperative nail deformities were quite mild and of little concern to the patient. There was no correlation between preoperative cyst drainage and aesthetic postoperative nail growth. Nail removal at the time of surgery appeared to be unnecessary unless the nail was grossly disrupted.     

Quantitative trace element analysis of human nails with external beam PIXE

External beam PIXE (Particle Induced X-ray Emission) analysis with a proton beam of 2.4 MeV was used to study trace element concentrations in human nails. The suitability of PIXE analysis regarding nail samples without any pretreatment besides washing was investigated. The main emphasis has been on the ability to obtain absolute concentration values and a new accurate method for nail sample standardization has been developed. Concentration values for the elements Ca, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, and Pb were determined from human nail samples. A comparison was made with nail samples taken from different fingers and toes to monitor intraindividual variation, and nails of different healthy individuals to get a view of the interindividual differences. The concentrations were also measured in relation to time in order to observe any possible short-term changes. The results are compared with the previous studies reported in the literature. The nail analysis is also compared to hair analysis in terms of detection limits, number of elements determinable, and standardization of the results.     

Induction of hard keratin expression in non-nail-matrical keratinocytes by nail-matrical fibroblasts through epithelial-mesenchymal interactions

Epithelium in the nail matrix is different from that at other body sites, in terms of clinical and histological appearance. Hard keratins are exclusively expressed in the nail matrix and bed and the hair apparatus, and hard keratin is considered a differentiation marker of these sites. Whether the expression of hard keratin in non-nail-matrical keratinocytes could be induced by nail-matrical fibroblasts was examined. Skin equivalents were constructed in three ways; ventral keratinocytes (from the ventral side of the digit) were cocultured with ventral fibroblasts (group A), ventral keratinocytes were cocultured with nail-matrical fibroblasts (group B), and nail-matrical keratinocytes were cocultured with ventral fibroblasts (group C). Immunohistochemical examinations with anti-hard keratin antibody (HKN-7) revealed hard keratin expression in groups B and C. HKN-7-positive cells were distributed continuously in the entire epithelial strata or in the suprabasal layer in group B, whereas HKN-7-positive cells were distributed spottily in group C. This study indicates extrinsic hard keratin induction in non-nail-matrical keratinocytes by nail-matrical fibroblasts and suggests that non-nail-matrical epidermal grafts may be effective in the treatment of deepithelized nail injuries. In addition, it is possible that lost nails could be reconstructed with grafts of "tissue-engineered" nail equivalent.     

Effect of long-term therapy with sodium valproate on nail and serum trace element status in epileptic children

Antiepileptic drugs could cause changes in the trace element status of the body. Valproic acid (VPA) is a very effective anticonvulsant agent widely used in the management of various forms of epilepsy. Nail trace element content is a reliable index of trace element nutritional status of the body. To determine whether some of the side effects of antiepileptic drugs could be the result of zinc (Zn) depletion within tissues, Zn concentrations as well as copper (Cu) concentrations in nail and serum in 59 children having various types of epilepsy receiving valproate and 31 controls were assessed. Although serum Zn level in epileptic patients was found to be decreased, there was no difference in nail samples when compared to controls. There was a statistically significant increase in nail Cu level in epileptic patients when compared to controls. On the other hand, serum Cu levels were not different between the groups. Although none of our patients showed any symptoms of Cu elevation and Zn depletion, we should pay attention to potential body trace element changes in patients with epilepsy under VPA treatment. In conclusion, our results indicate that serum trace metal homeostasis might be affected by VPA therapy, but not by the convulsive disorder itself.     

Free nonvascularized composite nail grafts: an institutional experience

Free, nonvascularized composite nail grafts have been reported as a successful method to reconstruct nail deformities due to congenital anomalies or traumatic defects. The authors performed a decade review of their experience with nine patients who had had 10 free, nonvascularized composite nail grafts. Patient demographics, mechanism of injury, timing, site of reconstruction, and amount of nail to be replaced were all recorded. Results of nail growth in reconstructed nails were judged as excellent, good, fair, or poor on the basis of the appearance of the nail. The majority of reconstructed nails had half or more of the nail bed replaced. The 10 cases (mean follow-up of 1.8 years) that were reported had two excellent, three good, two fair, and three poor outcomes. There was no apparent relation between the successful outcome of the procedure and patient age, timing of reconstruction, or amount of nail bed replaced. Although the authors' experience suggests the unpredictable nature of this type of graft, it should be considered for patients who desire nail reconstruction and are not candidates for ablative or vascularized nail complex transfer procedures.     

Glycation of Nail Proteins: From Basic Biochemical Findings to a Representative Marker for Diabetic Glycation-Associated Target Organ Damage

Background

Although assessment of glycated nail proteins may be a useful marker for monitoring of diabetes, their nature and formation are still poorly understood. Besides a detailed anatomical analysis of keratin glycation, the usefulness of glycated nail protein assessment for monitoring diabetic complications was investigated.

Methods

216 patients (94 males, 122 females; mean age ± standard deviation: 75.0 ± 8.7 years) were enrolled. Glycation of nail and eye lens proteins was assessed using a photometric nitroblue tetrazolium-based assay. Following chromatographic separation of extracted nail proteins, binding and nonbinding fractions were analyzed using one-dimensional gel electrophoresis. Using a hand piece containing a latch-type-bur, a meticulous cutting of the nail plate into superficial and deep layers was performed, followed by a differential analysis of fructosamine.

Results

Using SDS PAGE, four and two bands were identified among the nonglycated and glycated nail fraction respectively. Significantly lower fructosamine concentrations were found in the superficial nail layer (mean: 2.16 ± 1.37 μmol/g nails) in comparison with the deep layer (mean: 4.36 ± 2.55 μmol/g nails) (P<0.05). A significant higher amount of glycated eye lens proteins was found in diabetes mellitus patients (mean: 3.80 ± 1.57 μmol/g eye lens) in comparison with nondiabetics (mean: 3.35 ± 1.34 μmol/g eye lens) (P<0.05). A marked correlation was found between glycated nail and glycated eye lens proteins [y (glycated nail proteins) = 0.39 + 0.99 x (eye lens glycated proteins); r² = 0.58, P<0.001]. The concentration of glycated eye lens proteins and the HbA1c level were found to be predictors of the concentration of glycated nail proteins.

Conclusions

Glycation of nail proteins takes place in the deep layer of finger nails, which is in close contact with blood vessels and interstitial fluid. Glycation of nail proteins can be regarded as a representative marker for diabetic glycation-associated target organ damage.     

Development and evolution of the mammalian limb: adaptive diversification of nails, hooves, and claws

SUMMARY Paleontological evidence indicates that the evolutionary diversification of mammals early in the Cenozoic era was characterized by an adaptive radiation of distal limb structures. Likewise, neontological data show that morphological variation in distal limb integumentary appendages (e.g., nails, hooves, and claws) can be observed not only among distantly related mammalian taxa but also among closely related species within the same clade. Comparative analysis of nail, claw, and hoof morphogenesis reveals relatively subtle differences in mesenchymal and epithelial patterning underlying these adult differences in distal limb appendage morphology. Furthermore, studies of regulatory gene expression during vertebrate claw development demonstrate that many of the signaling molecules involved in patterning ectodermal derivatives such as teeth, hair, and feathers are also involved in organizing mammalian distal limb appendages. For example, Bmp4 signaling plays an important role during the recruitment of mesenchymal cells into the condensations forming the terminal phalanges, whereas Msx2 affects the length of nails and claws by suppressing proliferation of germinal epidermal cells. Evolutionary changes in the form of distal integumentary appendages may therefore result from changes in gene expression during formation of mesenchymal condensations ( Bmp4 , posterior Hox genes), induction of the claw fold and germinal matrix ( shh ), and/or proliferation of epidermal cells in the claw matrix ( Msx1 , Msx2 ). The prevalence of convergences and parallelisms in nail and claw structure among mammals underscores the existence of multiple morphogenetic pathways for evolutionary change in distal limb appendages.     

Nail lengthening and fingertip amputations

Fingertip injuries can be treated in different ways, including shortening with primary closure, skin grafts, and local or distant flaps. Nail bed involvement complicates fingertip reconstruction and may influence the choice of treatment. Local flaps can usually replace the pulp and provide a satisfactory functional and aesthetic result, whereas reconstruction of the fingernail apparatus is more difficult. In the period between 1998 and 2001, 12 fingertip injuries with nail bed involvement were treated with a combination of local flaps (Tranquilli-Leali and Venkataswami flaps) and the eponychial flap. The eponychial flap described by Bakhach is a backward cutaneous translation flap that lengthens the nail plate and restores a good appearance of the nail apparatus. This technique is simple to use and can be used with different flaps for pulp reconstruction.     

Development of a locking femur nail for mice

We herein report on a novel locking intramedullary nail system in a murine closed femur fracture model. The nail system consists of a modified 24-gauge injection needle and a 0.1-mm-diameter tungsten guide wire. Rotation stability was accomplished by flattening the proximal and distal end of the needle. Torsional mechanical testing of the implants in osteotomized cadaveric femora revealed a superiority of the locking nail (3.9+/-1.0 degrees rotation at a torque of 0.9 Nmm, n=10) compared to the unmodified injection needle (conventional nail; 52.4+/-3.2 degrees, n=10, p<0.05). None of the implants, however, achieved the rotation stability of unfractured femora (0.3+/-0.5 degrees, n=10). In a second step, we tested the feasibility of the in vivo application of the locking nail to stabilize a closed femoral midshaft fracture in C57BL/6 mice. Of interest, none of the 10 animals showed a dislocation of the locking nail over a 5-week period, while 3 of 4 animals with conventional nail fracture stabilization showed a significant pin dislocation within the first 3 days (p<0.05). Mechanical testing after 5-weeks stabilization with the locking nail revealed an appropriate bone healing with a torque at failure of 71.6+/-3.4% and a peak rotation before failure of 68.4+/-5.3% relative to the unfractured contralateral femur. With the advantage that closed fractures can be fixed with rotation stability, the herein introduced model may represent an ideal tool to study bone healing in transgenic and knockout mice.     

Does the nail bed really regenerate?

From observations of nail bed injuries, the regeneration of the nail bed seemed evident. The nail bed regenerated well in the presence of the nail matrix and poorly in its absence, suggesting that the nail bed regenerated from the nail matrix. Full-thickness skin graft or flap coverage of nail bed defects resulted in the good nail bed regeneration. The nail bed grew back, pushing the graft or the flap distally. The regenerated nail beds were about 70 percent of normal size in guillotine-type amputations and about 90 percent in the presence of an intact distal phalanx. The difference between full- and split-thickness skin grafts seemed to be adherence to the phalangeal bone, the former giving way to the advancing nail bed and the latter staying in the way. In addition, the destination of the moving nail bed cells was discussed.