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At least 433 records · Page 24Linked to original sources
PubMed2005

Brittle nail syndrome: a pathogenesis-based approach with a proposed grading system.

Brittle nail syndrome is a heterogeneous abnormality, characterized by increased fragility of the nail plate. Brittle nails affect about 20% of the population and women are affected twice as frequently as men. The vast majority of patients experience brittle nails as a significant cosmetic problem and a substantial number indicate that these nail abnormalities are painful, impair daily activities, and may have a negative impact on occupational abilities. Pathogenic factors leading to brittle nails are factors that impair intercellular adhesion of the corneocytes of the nail plate or factors that cause a pathologic nail formation by involving the matrix. Clinical features of brittle nail syndrome are onychoschizia and onychorrhexis: the impairment of intercellular adhesive factors of the nail plate is expressed as onychoschizia, whereas the involvement of the nail matrix is expressed as onychorrhexis. Although impairment of life quality has not been evaluated for patients with brittle nail syndrome, the reduction of life quality in other nail problems has been studied and is evident. A proposed scoring system of key features of brittle nails is presented, and therapeutic approaches focussed on the pathogenic factors are discussed.

Diagnosis, Differential↗
PubMed1983

[Surgical interventions on the nail: indications and contraindications].

Nail surgery might be performed for diagnostic and therapeutic reasons. A diagnostic biopsy is indicated for unclear disturbances of nail formation, atypical inflammations, suspicious pigmentations and neoplasias of the nail organ. The following alterations have to be absolutely treated by surgery: solitary pigmented streaks, tumors, ingrowing nails (stage III), panaritium and traumatic injuries of the nail organ. Relative surgical indications are onychogryposis, nail mycoses, discolorations due to chromogenic bacteria and subungual warts, as well as large subungual haematomas, longitudinal split nails and recalcitrant chronic paronychias. However, there are some contraindications for surgical intervention especially for simple avulsions of the nail plate. With malformed nails due to matrix diseases, large scars of the nail bed or ingrowing nails, an extraction of the nail plate does not have any healing effect. Instead repeated nail extractions may cause thickening and overcurvature of the nail.

Biopsy↗
PubMed2005

Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures in adults.

BACKGROUND: Two types of implants used for the surgical fixation of extracapsular hip fractures are cephalocondylic intramedullary nails, which are inserted into the femoral canal proximally to distally across the fracture, and extramedullary implants. OBJECTIVES: To compare cephalocondylic intramedullary nails with extramedullary implants (e.g. the sliding hip screw) for extracapsular hip fractures in adults. SEARCH STRATEGY: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (June 2005), the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, the UK National Research Register, orthopaedic journals, conference proceedings and reference lists of articles. SELECTION CRITERIA: All randomised and quasi-randomised controlled trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures. DATA COLLECTION AND ANALYSIS: Both authors independently assessed trial quality and extracted data. Wherever appropriate, results were pooled. MAIN RESULTS: Predominantly older people with mainly trochanteric fractures were treated in the 32 included trials. Twenty trials, involving 3646 people, compared the Gamma nail with the sliding hip screw (SHS). The Gamma nail was associated with an increased risk of operative and later fracture of the femur and an increased reoperation rate. There were no major differences between implants in the wound infection, mortality or medical complications. Data were inadequate for other outcomes. Five trials, involving 623 people, compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group: all cases of operative and later fracture of the femur occurred in this group. Results for post-operative complications, mortality and functional outcomes were similar in the two groups. Two trials involving 314 people showed no difference in fracture fixation complications, reoperation, wound infection and length of hospital stay for proximal femoral nail (PFN) compared with the SHS. Single trial comparisons (experimental mini-invasive static intramedullary nail compared with the SHS: 60 participants; Kuntscher-Y nail with the SHS: 230 participants; Gamma nail and the Medoff sliding plate: 217 participants) failed to provide sufficient evidence to establish differences between implants in outcome. Two trials, involving 65 people with reverse and transverse fractures at the level of the lesser trochanter, found intramedullary nails (Gamma nail or PFN) were associated with better intra-operative results and fewer fracture fixation complications than extramedullary implants (a 90-degree blade plate or dynamic condylar plate) for these fractures. AUTHORS' CONCLUSIONS: Given the lower complication rate of the SHS in comparison with intramedullary nails, SHS appears superior for trochanteric fractures. Further studies are required to determine if different types of intramedullary nail produce similar results, or if intramedullary nails have advantages for selected fracture types (for example, subtrochanteric fractures).

Adult↗
PubMed1999

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.

Humans↗
PubMed1994

Characterization of nail matrix melanocytes with anti-PEP1, anti-PEP8, TMH-1, and HMB-45 antibodies.

BACKGROUND: The normal nail matrix contains quiescent melanocytes with a peculiar arrangement and behavior. OBJECTIVE: Our purpose was to identify nail matrix melanocytes with antibodies that recognize melanocytic cells in tissue sections. METHODS: We used the polyclonal antibodies anti-PEP1 and anti-PEP8 and the monoclonal antibody TMH-1, which recognize melanocytic enzymes, and the monoclonal antibody HMB-45, which reacts with melanoma cells and fetal melanocytes, but not with normal adult melanocytes. Nail matrix specimens were obtained from longitudinal specimens of eight white patients with ingrown toenails. Specimens from normal adult forearm skin were used as controls. RESULTS: All nail specimens gave similar results. Dendritic melanocytes were more numerous in the distal than in the proximal nail matrix. They were not restricted to the basal layer, but were also found in the suprabasal layers of the nail matrix epithelium. Melanocytes were seen both a single dendritic cells among the nail matrix keratinocytes and as small clusters that appeared irregularly distributed along the length of the nail matrix. Each cluster usually consisted of three to four cells. CONCLUSION: Even if normally quiescent, nail matrix melanocytes possess the key enzymes responsible for the formation of melanin. The suprabasal location of nail matrix melanocytes may be a consequence of the distribution of adhesion molecules in the nail epithelium. In fact, in the nail matrix alpha 2, alpha 3, and beta 1 integrins are not only expressed on the basal, but also on the fourth to fifth suprabasal layers, with suprabasal expression gradually decreasing from distal to proximal matrix. The behavior of nail matrix keratinocytes may cause the peculiar arrangement and behavior of nail matrix melanocytes.

Antibodies, Monoclonal↗
PubMed1997

Knee pain after tibial nailing.

OBJECTIVE: To determine the incidence and natural history of knee pain following tibial nailing. DESIGN: A retrospective analysis of patients treated by tibial nailing evaluating a consecutive series of patients with isolated tibial shaft fractures. SETTING: A level one trauma center in Vancouver, British Columbia. PATIENTS: A group of 107 consecutive patients with 110 tibial fractures treated by interlocking tibial nailing. INTERVENTION: Patients were contacted and interviewed by the authors. Clinical records and radiographs were analysed. MAIN OUTCOME MEASUREMENTS: Incidence of knee pain; time of onset; relationship of nail position on radiographs to knee pain; relationship to knee pain to site of nail insertion; response to nail removal. RESULTS: At a mean follow-up period of thirty-two months (12-58 months), sixty-one (57%) patients (63 of 110 knees) had developed anterior knee pain. There was no correlation between nail protrusion and knee pain. Insertion of the nail through the patella tendon was associated with a higher incidence of knee pain compared to the paratendon site of nail insertion (77% and 50% respectively). Of patients with knee pain, 80% (49/61) required nail removal. At a mean duration of 16 months following nail removal, pain was completely relieved in 22 patients and partially relieved in 17. In the remaining 10 patients, there was no improvement. CONCLUSIONS: Based on this data, we would recommend a parapatellar tendon incision for nail insertion, and nail removal for those patients with a painful knee. The causes of knee pain after tibial nailing are multi-factorial and require further study.

Adolescent↗
PubMed2005

Efficacy of triamcinolone acetonide in various acquired nail dystrophies.

The treatment of nail disorders is currently an unsatisfying exercise. Isolated nail involvement generally does not warrant any systemic therapy. At the same time, treatment is requested because of significant cosmetic and functional handicap. Intralesional triamcinolone acetonide (TA) in the proximal nail fold was evaluated as a treatment modality in 30 patients with twenty-nail dystrophy, 14 with nail lichen planus, and 6 with nail psoriasis. The number of involved nails varied from 1-20, and 1-10 nails were treated with TA. Fourteen patients discontinued treatment after 1-2 sittings. Out of the 28 patients completing the treatment protocol, 16 showed 75-100% improvement. Predominant side effects included pain, subungual hematoma formation, proximal nail fold hypopigmentation, and atrophy. TA given as a single injection in the proximal nail fold produced good improvement in a significant number of patients completing the treatment protocol. Lower concentrations of TA (5 mg/ml) were quite effective in treating various dermatoses affecting the nail unit. Our technique had fewer side effects than needle-less injection or multiple injection techniques. Careful attention to injection technique further minimized the side effects associated with the procedure. Sixteen patients completed the six-month follow-up and a relapse of nail changes was seen in 10. The relapses were equally responsive to retreatment. TA injected into the proximal nail fold area is a useful, cheap and efficacious treatment for dermatoses affecting the nail unit.

Adolescent↗
PubMedDate not supplied

In vitro biomechanical comparison of solid and tubular interlocking nails in neonatal bovine femurs.

This study biomechanically evaluates solid and tubular interlocking nails in bovine neonatal femurs. Paired femurs from 40 neonatal dairy calves were obtained for mechanical testing. Intact femurs and four combinations of experimentally manipulated femurs (intact or ostectomized femurs with either a solid or tubular interlocking nail) were tested in craniocaudal and lateromedial bending, eccentric axial compression, and external torsion to evaluate composite rigidity, local/gap stiffness, and load to failure (compression and torsion only). In torsional composite rigidity, femurs with tubular interlocking nails were more complaint than intact femurs or intact femurs with solid interlocking nails (P < .001). Ostectomized femurs with solid interlocking nails were similar to intact femurs with tubular interlocking nails. Within femurs with tubular interlocking nails, ostectomized femurs were more compliant than intact femurs (P < .0001). In craniocaudal and lateromedial bending rigidity, ostectomized femurs were more complaint than intact femurs, regardless of interlocking nail type (P < .001). Within ostectomized femurs, tubular interlocking nails were more complaint than solid interlocking nails in craniocaudal bending (P < .05) and there was a similar trend in lateromedial bending (P = .06). In eccentric axial compression, local/gap stiffness was significantly greater in intact femurs compared with intact femurs with solid (48% of intact bone) or tubular (45% of intact bone) interlocking nails and ostectomized femurs with solid (18% of intact bone) or tubular (11% of intact bone) interlocking nails (P < .0001). In torsional testing, local/gap stiffness was not significantly different between intact femurs and intact femurs with interlocking nails, but was significantly lower in ostectomized femurs with solid (2% of intact bone) and tubular (0.2% of intact bone) interlocking nails (P < .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1999

Drug permeation through the three layers of the human nail plate.

The in-vitro permeation characteristics of a water soluble model drug, 5-fluorouracil, and a poorly water soluble model drug, flurbiprofen, were investigated through three layers of the human nail plate (namely, the dorsal, intermediate and ventral nail plates), using a modified side-by-side diffusion cell. The dorsal-filed nail plate, the ventral-filed nail plate and the dorsal-and-ventral-filed nail plate were prepared to known thicknesses and then used with the full-thickness nail plate to investigate the permeation characteristics of each single layer. Most of the lipids in the human nail plate were found in the dorsal and ventral layers. The rank orders of the permeation fluxes for 5-fluorouracil and flurbiprofen were both: dorsal-and-ventral-filed nail plate > dorsal-filed nail plate > ventral-filed nail plate > full-thickness nail plate. With respect to 5-fluorouracil permeation through each single layer, the permeability coefficient of the intermediate layer was higher than those of other single layers. However in the case of flurbiprofen, the permeability coefficient of the ventral layer was higher than other single layers. The diffusion coefficients of 5-fluorouracil and flurbiprofen in the dorsal layer were the lowest of any single layer. The drug concentration in each layer was estimated using each respective permeation parameter. The drug concentration in the nail plate was observed to be dependent on the solubility and the flux of the drug. From these findings, we suggest that the human nail plate behaves like a hydrophilic gel membrane rather than a lipophilic partition membrane and that the upper layer functions as the main nail barrier to drug permeation through its low diffusivity against the drugs.

Diffusion↗
PubMed1996

Quantification of regional matrix nail production.

The relative nail producing capacity of different regions within the nail matrix has not been quantified. In order to do this, the number of nail plate cells in the dorsoventral axis of 12 human great toenails was counted at five sites in the longitudinal axis, and compared with direct measurements of nail plate thickness at the same sites. The mean number of nail cells in the nail plate reached a maximum at the lunula, with no further increase along the length of the nail bed. At the mid-point between the proximal tip of the germinal matrix and lunula, mean cell numbers achieved 81% of the value at the lunula. Mean nail thickness was only 90% of its maximum at the lunula, with a further significant increase (P = 0.02) between the lunula and end of the nail bed. These observations suggest that the proximal nail matrix is the main source of nail within the matrix. This is consistent with clinical experience where distal matrix surgery has a low potential for scarring in comparison with proximal matrix surgery. The additional finding of increased nail thickness, but not cell numbers, along the nail bed make it likely that cells within the nail plate change shape as they move distally.

Adolescent↗
PubMed1998

Biomechanical comparison of antegrade and retrograde nailing of humeral shaft fracture.

A pair-controlled study was conducted to compare biomechanical properties of antegrade and retrograde nailing of humeral fractures. First, six paired fresh anatomic specimen humeri were used to compare the properties of humeri fractured at the middle to distal diaphyses junction that were nailed from the retrograde approach with the Humeral Locked nail with those of contralateral intact humeri. An 18 additional pairs were divided into three equal groups by distal, proximal, or mid-diaphysis location of a standardized 5-mm bone defect to simulate unstable fractures. The retrograde and antegrade nailings were performed in each pair in a random manner. Nail and bone constructs were tested for bending stiffness by nondestructive three-point bending and for torsional stiffness by destructive torsional tests. Compared with intact humeri, fractured humeri fixed with nails had 28.6% posteroanterior and 31.4% mediolateral bending stiffness, 22.5% torsional stiffness, and 43.3% failure torque. For distal fractures, retrograde nailing showed significantly more initial stability and higher bending and torsional stiffness; for proximal fractures, antegrade nailing showed similar properties. For middle to distal diaphyses junction fractures, retrograde and antegrade nailing were indistinguishable. The defect created as an entry portal for retrograde nailing reduced the bone strength only 11.1%. These results suggest that retrograde nailing, which is less detrimental to shoulder function than is antegrade nailing, is an acceptable alternative treatment for humeral shaft fractures. In addition, nailing from the short to the long bone segments can improve mechanical properties of the fixation construct because of better nail and bone interface purchase.

Biomechanical Phenomena↗
PubMed2004

The successful treatment of Trichophyton rubrum nail bed (distal subungual) onychomycosis with intermittent pulse-dosed terbinafine.

BACKGROUND: The standard treatment of Trichophyton rubrum nail bed onychomycosis (or distal subungual onychomycosis [DSO]) with daily terbinafine for 12 weeks involves treating for a fixed period shorter than the time required for complete replacement of the nail bed and overlying nail plate by normal growth. The same total amount of terbinafine pulse-dosed for approximately 12 months would treat the patient until normal replacement of the mycotic nail bed has occurred. OBJECTIVES: To determine the effectiveness of intermittent administration of oral terbinafine (250 mg/d for 7 consecutive days every 2-4 months) to cure DSO and to determine the maximum effective treatment interval. DESIGN: A prospective, nonrandomized, open study of sequential groups of office patients. SETTING: A private dermatology practice. METHODS: A sequence of 4 groups of office patients with DSO (n = 10-20 each) were treated with pulse-dosed terbinafine for 7 consecutive days at intervals of 2, 3, and 4 months, respectively. In each group, treatment was continued until the distally advancing new nail bed and nail had completely removed the mycotic defect or failure of fungistasis was detected. MAIN OUTCOME MEASUREMENT: Results were determined by monthly evaluation. Cure was noted as complete replacement of the mycotic nail bed and overlying nail plate (ascertained by monthly metric measurements of the mycosis-free nail bed and overlying nail place distal to the proximal nail fold). Treatment failure was noted when the mycosis-free proximal portion of the nail bed failed to increase in correspondence with the distally directed movement of the nail bed and overlying nail. RESULTS: Thirty-nine (93%) of the 42 patients in the first 3 groups were cured (95% binomial confidence interval, 67%-100%) with no evidence of decrease in efficacy. However, the group of patients who received the 7-day pulse treatment every 4 months experienced significantly more failures (P<.01), and cures dropped to 10 of 17 cases. CONCLUSION: Terbinafine is an effective treatment for DSO when pulse-dosed for 7 days every 3 months but not every 4 months.

Administration, Oral↗
PubMed2005

The effect of locked distal screws in retrograde nailing of osteoporotic distal femur fractures: a laboratory study using cadaver femurs.

OBJECTIVES: To examine the effects of locked distal screws in retrograde nails used in unstable osteopenic distal femur fractures. DESIGN: Biomechanical testing of paired human cadaveric femurs. INTERVENTION: Seven matched pairs of embalmed, moderately osteopenic cadaver femurs were instrumented with 12-mm intramedullary nails in a statically locked, retrograde fashion. One femur of each pair had locked distal screws and the other femur had unlocked distal screws. A 2.5-cm gap of bone was cut nine centimeters from the distal condyles to simulate an unstable fracture. The locked distal screw nails were compared to unlocked distal screw nails for collapse of the fracture gap, medial-lateral and anterior-posterior translation of the nail within the fracture site, and fracture angulation. The femurs were axially loaded, cycled, and then loaded to failure. MAIN OUTCOME MEASURES: Motion at the fracture site with axial cyclic loading and site of failure when loaded to failure. RESULTS: After cycling, both locked distal screw and unlocked distal screw nails demonstrated several millimeters medial and anterior translation within the fracture site and approximately 1 mm collapse of the fracture gap. Although no statistically significant differences were found, the locked distal screw nails had less anterior and medial translation, angulation, and collapse of the fracture gap after cycling. Loads to failure were similar for both locked distal screw and unlocked distal screw nails. It was noted that proximal femur failure occurred at the level of the proximal screw hole in the nail at the subtrochanteric level in 7 (4 locked distal screws and 3 unlocked distal screw groups) of the 14 samples. Four other samples failed through the intertrochanteric region (2 locked distal screw and 2 unlocked distal screw groups) and the remainder within the distal fragment by fracture of the femur along the medial cortex. CONCLUSIONS: Although most differences in fixation stability were not significant, the locked distal screw nails exhibited less fracture collapse and anterior and medial translation of the nail at the fracture site than the unlocked distal screw nails. The degree of varus angulation after cyclic loading was also less for the locked distal screw nails. The length of the nail chosen should avoid having proximal locking screws distal to the lesser trochanter, thus averting proximal femur stress risers and fractures.

Bone Screws↗
PubMed1991

[Bundle nailing of forearm fractures. Indications and results].

Hackethal developed the nailing procedure named after him in 1959. The rationale of Hackethal nailing is an elastic jamming, which can only be achieved by obeying four rules: jamming of the nails in the cortical window, jamming then in the waist of the medullary cavity, spreading the bunch of nails in the metaphysis and filling up the conus of the medullary cavity with short nails. We confined Hackethal nailing to closed and first-degree open fractures of the 2nd-5th sixth of the shaft of the forearm. If closed reduction and nailing were impossible, we performed a plate fixation (AO), in second- or third-degree open fractures we treated with fixators (Orthofix). In a 13-year period we performed Hackethal bundle nailing in 65 patients with 115 fractures. In 54% patients surgery was performed within the first 8 hours following admission. We used two or three nails passing the fracture and one short nail. Except for 1 case, in which we needed a plaster of Paris, we achieved rational stability. On average, the nails were removed after 11.5 months. The healing and complication rates were assessed by follow-up examination of 49 patients. The results were excellent and good in 71.5% patients, satisfactory 11.4% and poor in 17.1%. Complications consisted of a 2.1% infection rate (osteitis), 3.1% non-union, 2.1% with a synostosis, 1% refracture (during removal of the nails) and 3.1% migration of nails, combined with tendon rupture. We have seen 1 case with metallosis. In conclusion with our confined spectrum of indications Hackethal nailing is a low-risk method, which leads to a rational stability and early bone healing.

Adult↗
PubMed1996

[Systemic complications in intramedullary nailing].

Today intramedullary nailing is the treatment of choice in stabilizing femoral and tibial diaphysial fractures because of its superior bone healing compared to other forms of osteosyntheses. By interlocking, the indication can be extended to all fractures in which interlocking bolts can be fixed in the proximal and distal main fragment. Küntscher's principle of elastic clamp has changed to intramedullary splinting. With that method reaming is limited to a few reaming processes, and unreamed nailing has become possible. Today implants start at a diameter of 9 mm. The diameter of implants of all manufacturers is less than a few years ago. Since the importance of embolization by increasing the intramedullary pressure as a result of reaming is accepted, the question arises concerning the clinical relevance of embolization if reaming is restricted and unreamed nails are applied. In our own investigations, relevant intravasation of bone marrow content appeared only in reamed femoral nailing. The bone marrow cavity of the tibia is smaller, the configuration of the tibia allows more back-streaming of the content, and the venous drainage system in the distal tibia is much less extensive than in the supracondylar area. All pulmonary complications in the literature are reported after nailing of femoral fractures. Therefore, systemic complications in intramedullary nailing are only a problem in femoral fractures. The pathophysiological connection between intramedullary pressure increases and pulmonary impairment is not clarified in detail. Relevant content of the bone marrow cavity is not only bone marrow, but also the blood with which the marrow cavity is refilled after each reaming process and which passes into the circulation during the following reaming. This blood is activated concerning coagulation. By reaming, the pathogenic content of the bone marrow cavity is embolized, which can become clinically relevant if cofactors are present. Cofactors are volume deficit, shock, lung contusion and pre-existing pulmonary impairment. These conditions can never be excluded before primary stabilization after trauma. Today the importance of systemic complications during unreamed nailing is controversial. Our experimental and echocardiographic investigations clearly show that the velocity of the nail into the bone marrow cavity and the gap between the nail and cortical bone at the entrance in the distal fragment determine the amount of embolized material. By carefully inserting the nail and choosing thin nails with a correct length, which can gain stability by fixation in the condylar area and not by clamping in the distal fragment, echocardiography reveals only minimal embolization. Therefore unreamed nailing is the treatment of choice, if the situation of the patient allows the procedure of nailing in itself. Multitrauma patients in shock or with unstable circulation should be stabilized primarily with external fixation. After consolidation, early change to an intramedullary nail should be performed.

Embolism, Fat↗
PubMed2002

Drug delivery to the nail following topical application.

The absorption of drugs into the nail unit, following topical application to the nail plate, is highly desirable to treat nail disorders, such as onychomycosis (fungal infections of the nail). Nail permeability is however quite low and limits topical therapy to early/mild disease states. In this paper, the recent research into ungual drug delivery is reviewed. The nail unit and the two most common diseases affecting the nail--onychomycosis and nail psoriasis--are briefly described to set the scene and to give an overview of the nature and scope of the problem. The factors, which affect drug uptake and permeation through the nail plate such as solute molecular size, hydrophilicity/hydrophobicity, charge, and the nature of the vehicle, are then discussed, followed by ways of enhancing drug transport into and through the nail plate. Finally, drug-containing nail lacquers which, like cosmetic varnish, are brushed onto the nail plates to form a film, and from which drug is released and penetrates into the nail, are reviewed.

Administration, Topical↗
PubMed1997

Anatomic distribution of melanocytes in normal nail unit: an immunohistochemical investigation.

Very few histologic reports describe normal melanocytes of the nail unit. Previous studies predominantly address the distal nail matrix melanocytes; we found no review of nail-bed melanocytes in the literature. The proximal nail matrix melanocytes are difficult to identify; the cells cannot be identified by L-DOPA staining. More recently, their scarcity was confirmed by immunohistochemistry with a large panel of antibodies directed against melanocytes. We wished to detect the proximal nail matrix dormant melanocytes and compare their density and distribution with that of the other melanocytes in the distal matrix and nail bed and to establish criteria of normality that may help clarify the pathologic features of benign nevoid melanonychia in the nails of whites. A panel of five monoclonal antibodies (MoAbs), including HMB45 and TRP1 directed against antigens localized in early melanosomal vesicles, was investigated in frozen sections of six nail specimens from whites. Both vertical and horizontal sections were assessed to determine the presence of dormant melanocytes. Results showed that the proximal nail matrix melanocytes were clearly identified with MoAbs HMB45 and tyrosinase-related protein-1 (TRP-1). By contrast, melanocytes stained by MoAb against tyrosinase and L-DOPA reaction were evident, especially in the distal matrix. With MoAb TRP-1, the epithelial sheets showed counts of approximately 217+/-84/mm2 in the proximal matrix and of 132+/-34/mm2 in the distal matrix; the nail bed counts were only 45+/-25/mm2. The split epithelial sheets had 103+/-17/mm2 L-DOPA-positive melanocytes in the distal third of the matrix, but only a few of them were detected in the proximal matrix and none were noted in the nail bed. We clearly identified proximal nail melanocytes using MoAb HMB45 and TRP1. The total number of matrix melanocytes can be estimated as approximately 217/mm2. In proximal matrix, the dormant melanocytes compartment was predominant. In the distal matrix, two compartments were identified: a functionally differentiated and a dormant compartment. Contrary to classical opinion, longitudinal melanonychia originates more frequently in the distal matrix, not secondary to the larger melanocyte density but because only the distal matrix contains an active melanin synthesis compartment. Furthermore, the superficial distribution of proximal nail melanocytes in vertical sections showed a histologic feature that may simulate the pagetoid pattern of melanoma in situ.

Aged↗
PubMed1996

Proliferative compartments in the normal nail unit.

The main distinction between the germinal matrix and the nail bed is that the former is the origin of all or most of the nail plate and the latter provides an epithelial surface to which the emerging nail can adhere. It has been argued that the nail bed may contribute substance to the nail plate and it is likely that if this was the case, epithelial proliferation in the nail bed would match that in the germinal matrix by a proportion appropriate to its contribution. We have measured the labelling index (LI) in the three major anatomical sites of the nail unit using two antibodies to antigens expressed in cycling cells. Using Ki-67 (MIB-1) and proliferating cell nuclear antigen (PCNA) as markers of cell proliferation we have defined the LI in the germinal matrix (MIB-1: 22.1%, PCNA: 33%), nail bed (MIB-1: 0.75%, PCNA: 1%) and digit pulp (MIB-1: 16.8%, PCNA: 17.4%). This suggests a low degree of proliferation in normal nail bed consistent with a minimal or non-existent contribution to the nail plate. This may change in hyperkeratotic nail dystrophies, where the nail bed LI is raised (MIB-1: 31%, PCNA: 29%), illustrating how nail bed behaviour can alter with disease.

Adolescent↗