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At least 109 records · Page 6Linked to original sources
PubMed1981

Physicochemical characterization of the human nail: I. Pressure sealed apparatus for measuring nail plate permeabilities.

Diffusion characteristics of the nail plate are necessary in providing the baselines for rational topical management of nail infections. In order to develop such baselines a unique stainless steel diffusion cell has been designed. The cell permits the exposure of 0.38 cm2 of nail plate to a bathing medium which is stirred by small motors mounted above the cell. The diffusion of water, methanol and ethanol at constant temperature (37 degrees C), has been examined over periods up to 4 h. Average permeability coefficients of water, methanol and ethanol were determined as 16.5 +/- 5.9 X 10(-3) cm hr-1, 5.6 X 10(-3) cm hr-1 and 5.8 +/- 3.1 X 10(-3) cm hr-1 respectively. Moreover rates of diffusion across the nail were inversely proportional to nail thickness. Based on methanol data, nail plate barrier property appears stable for long periods of aqueous immersion.

Diffusion↗
PubMed2005

Immunology of the human nail apparatus: the nail matrix is a site of relative immune privilege.

The nail apparatus is constantly exposed to environmental damage. It requires effective immune responses to combat infection, while avoiding the loss of nail production and regeneration by autoaggressive immunity. By immunohistology, we define here previously unknown characteristics of the normal human nail immune system (NIS). Compared with other regions of nail epithelium, human leukocyte antigen (HLA)-A/B/C expression is prominently down regulated on both keratinocytes and melanocytes of the proximal nail matrix (PNM), whereas HLA-G(+) is upregulated here. Together with the expression of macrophage migration inhibitory factor in PNM, this may serve to inhibit an natural killer (NK) cell attack on major histocompatibility complex (MHC) class Ia-negative PNM. PNM also displays strong immunoreactivity for potent, locally generated immunosuppressants such as transforming growth factor-beta1, alpha-melanocyte stimulating hormone, insulin-like growth factor-1, and adrenocorticotropic hormone, exhibits unusually few CD1a(+), CD4(+), or CD8(+), NK, and mast cells. Finally, MHC class II and CD 209 expression on CD1a(+) cells in and around the PNM is reduced, indicating diminished antigen-presenting capacity. Thus, the NIS strikingly differs from the skin immune system, but shows intriguing similarities to the hair follicle immune system, including the establishment of an area of relative immune privilege in the PNM. This nail immune privilege may offer a relative safeguard against autoimmunity. But, the localized intraepithelial defect of innate and adaptive immunity in the PNM revealed here also may impede effective anti-infection defense.

Antigens, CD↗
PubMed1995

The allergens of nail polish. (I). Allergenic constituents of common nail polish and toluenesulfonamide-formaldehyde resin (TS-F-R).

Nail polish that has completely dried on the fingernails contains water-soluble components that attain the skin during extensive but transient contact. This was proven by water extraction of thin layers of nail polish that had been painted onto glass plates and allowed to dry for 3 days. Comparing the isolated fractions and compounds with known nail polish ingredients revealed that the water-soluble substances are para- and ortho-toluenesulfonamide, dibutyl phthalate and 3 constituents of toluenesulfonamide-formaldehyde resin (TS-F-R), which is the basic material of almost all nail polishes sold worldwide. 12 female patients with proven nail polish allergy were patch tested with 21 nail polish components, including those isolated. Only 2 fractions were positive. These contained a monomer and a dimer created during condensation of TS-F-R. Their structures were elucidated. The 3rd compound, a trimer, remained negative, except in 1 case.

Allergens↗
PubMed1997

In-vitro permeability of the human nail and of a keratin membrane from bovine hooves: penetration of chloramphenicol from lipophilic vehicles and a nail lacquer.

Lipophilic vehicles and especially nail lacquers are more appropriate for topical application on the nail than aqueous systems because of their better adhesion. This work has, therefore, studied the penetration through the human nail plate of the model compound chloramphenicol from the lipophilic vehicles medium chain triglycerides and n-octanol and from a lacquer based on quaternary poly(methyl methacrylates) (Eudragit RL). The results were compared with data obtained with a keratin membrane from bovine hooves. If the swelling of the nail plate or the hoof membrane is not altered by use of lipophilic vehicles, the maximum flux of the drug is independent of its solubility in the vehicle and is the same as that from a saturated aqueous solution. These vehicles are not able to enter the hydrophilic keratin membrane because of their non-polar character and so cannot change the solubility of the penetrating substance in the barrier. If the concentration of the drug in the nail lacquer is sufficiently high, the maximum flux through both barriers equals that from aqueous vehicles or even exceeds it because of the formation of a supersaturated system. Penetration through the nail plate follows first order kinetics after a lag-time of 400 h. The course of penetration through the hoof membrane is initially membrane-controlled and later becomes a matrix-controlled process because of the membrane's greater permeability. Chloramphenicol is dissolved in the lacquer up to a concentration of 31%. The relative release rates from these solution matrices are independent of the drug concentration but they decrease on changing to a suspension matrix. These results show that drug flux is independent of the character of the vehicle and that penetration of the drug is initially membrane-controlled and changes to being matrix-controlled as the drug content of the lacquer decreases.

1-Octanol↗
PubMed1996

Levels of fluconazole in normal and diseased nails during and after treatment of onychomycoses in toe-nails with fluconazole 150 mg once weekly.

Thirty-six patients with onychomycoses of their toe-nails were included in a double-blind, parallel-group comparative study of fluconazole 150 mg once weekly and griseofulvin 1,000 mg once daily for 12 months, or earlier if cured. Every month during treatment and in cured patients 3 and 6 months after stop of treatment one toe-nail was clipped and serum samples were taken. In patients treated with fluconazole the concentration of fluconazole was measured in serum and nails. We found a very high concentration of fluconazole in nails (peak 8.54 micrograms/g) and the nail concentration was statistically significantly higher than serum concentrations (p < 0.001). In cured patients fluconazole was still present in high concentrations 3 (1.7 micrograms/g) and 6 (1.4 micrograms/g) months after stop of treatment. These results indicate that fluconazole should be effective in the treatment of onychomycosis in a dose of 150 mg once weekly. The results also indicate that the treatment period could be shortened because fluconazole is still present in high concentrations 6 months after stop of therapy. The concentration of fluconazole found in nails is much higher than that found in the case of terbinafine and itraconazole, indicating that fluconazole should be at least as effective as these drugs in the treatment of tinea unguium.

Antifungal Agents↗
PubMed2000

Anterograde femoral nailing with a reamed interlocking titanium alloy nail.

Intramedullary nailing has become the gold standard for treatment of femoral diaphyseal fractures. Between March 1995 and December 1998 we performed 40 intramedullary nailings using the ACE femoral nail (De Puy). The patients were followed for an average of 27.9 months (range: 6-54 months). The mean age was 33.2 years (range: 17-87 years); the sex distribution was 33 males and 7 females. All fractures were unilateral (right 18, left 22). Most of the fractures were caused by traffic accidents (35), the others originated from sports, work and gunshot (1). Thirty-five fractures were closed and 5 were open: 1 was grade I, 2 were grade II and 2 grade IIIa according to Gustilo's classification. According to the AO classification 18 fractures were type A, 13 type B and 9 type C. The majority of patients had associated injuries: neurotrauma 2, chest trauma 2, and other fractures e.g. of the clavicula, lumbar spine, patella, tibia. Immediate surgery was performed in 34 cases, delayed surgery in 6 cases. All fractures were treated on a fracture table, with closed reduction, reaming of the intramedullary canal, proximal and distal locking and intraoperative control of rotation and length. The mean time to healing was 17.85 weeks (range: 18-50 weeks). The following complications were observed: 3 delayed unions, which united after dynamisation, one malunion, which required corrective osteotomy, and one nonunion, which healed after exchange nailing. We encountered no rotational deformity and no clinically relevant shortening. Six nails were removed due to irritation by locking screws. These results are comparable with those of larger series in the literature with other types of interlocking nails. The union rate in this series was 97.5%.

Adolescent↗
PubMed1998

Unreamed nailing of tibial fractures with the solid tibial nail.

In 1993 a solid 7.5-mm tibial nail was developed and is composed of a wrought stainless steel alloy. In a preclinical testing series its static and dynamic mechanical properties proved to be superior to other small diameter nails. The clinical application of the Solid Tibial Nail in 70 cases of acute tibial diaphyseal fractures showed promising results. Neither severe intraoperative complications nor infections were observed. The entire series, including seven Grade I, eight Grade II, four Grade IIIA, and nine Grade IIIB open fractures, revealed a union rate of 95% at 6 months postoperative. After dynamization in one case and reaming and renailing in three cases, the fractures with delayed healing progressed to union within the following 3 months. There was no need for bone grafting in any of the cases. Locking screw breakage was observed in 10 (14%) cases 8 to 24 weeks postoperatively. This did not lead to any additional complications. No nail failures were observed. The excellent results of unreamed nailing with the Solid Tibial Nail consequently led to its use as the primary method of treatment for tibial fractures associated with soft tissue injury at the authors' institution.

Adolescent↗
PubMed2003

[Taking a biopsy, treating ingrown nails. Minor nail surgery in general practice].

Prior to any surgical operation on fingernails or toenails a diagnosis, or at least a suspected diagnosis, must be established. Suitable material for histopathology can be obtained by various methods: lateral longitudinal biopsy, matrix biopsy, and nail bed or nail wall biopsy. Of the surgical options, nail extraction is rarely indicated, and if at all, should be only partial. In the presence of trauma, a careful examination should be made for fracture of the terminal phalanx; where necessary, the matrix and bed must be sutured. Advanced onychogryposis is treated by applying carbolic acid to the matrix. In the case of ingrown toenails and, where applicable, "tubular nails", surgical nail paring is indicated whenever conservative measures fail.

Biopsy↗
PubMed1981

Nail growth direction revisited. Why do nails grow out instead of up?

In some investigations Kligman has been thought to have shown that the cul-de-sac in which the nail is formed determines that it should grow outward instead of upward. However, results obtained during the course of nail surgery for chronic paronychia and electron microscopic studies, along with genetic evidence, fail to confirm his observation on the effect of the proximal nail fold on nail growth direction. The whole subject of direction of nail growth remains questionable and worthy of further consideration.

Humans↗
PubMed1986

Longitudinal nail biopsy in evaluation of acquired nail dystrophies.

We reviewed longitudinal nail biopsies performed at Henry Ford Hospital on patients with acquired nail dystrophies to see whether the procedure did, indeed, provide useful diagnostic information and to see which microscopic features were most helpful in histopathologic diagnosis. Clinical diagnoses included psoriasis, lichen planus, Darier's disease, isolated longitudinal defects, and diffuse thickening. We found that clinical diagnosis could be supported by histopathologic findings in eight of twenty cases of acquired nail dystrophy. Specifically, we were able to make a diagnosis of psoriasis in four cases, lichen planus in three cases, and Darier's disease in one case. The other twelve cases showed nonspecific eczematous changes. We conclude that the longitudinal nail biopsy may be a useful diagnostic tool in certain cases of acquired nail dystrophy.

Biopsy↗
PubMed2000

Yellow nail syndrome: the nail that grows half as fast grows twice as thick.

We report a case of a 51-year-old man with yellow nail syndrome (YNS).1 During a 23-week period of study, the dynamics of thumbnail growth were compared between one affected thumb and the normal contralateral thumb. Longitudinal nail growth was normal (0.46 mm/week) in the normal thumb and double that of the affected thumb (0.23 mm/week). Thickness of nail at the free edge in the affected thumb (0.97 mm) was twice that of the normal thumb (0.57 mm). Within the nail plate in the dorso-ventral axis there were 50% more cells in the affected thumb (358) in comparison with the contralateral control (242). This case illustrates that rate of longitudinal growth does not necessarily reflect nail plate production.

Humans↗
PubMed1997

Nail-Tutor: an image-based personal computer program that teaches the anatomy, patterns of pathology, and disorders of the nails.

Despite the clinical relevance of the nails, the interpretation of the appearance of the nails is often neglected by clinicians and in medical training programs. To help overcome this we developed Nail-Tutor(TM), a personal computer program based on approximately 150 images that systematically teaches the anatomy, patterns of pathology, and diseases of the nails and tests the user's understanding of the material in the program. Nail-Tutor(TM) is intended for medical students, residents, other healthcare trainees, general practitioners, and dermatologists and requires approximately 3 hours to use. The program has a number of advantages over textbook-based instruction and supervised instruction. It does not require an instructor or textbook. In addition it uses animation to show an important anatomic relationship, graphic overlays to unambiguously point out key features of images, it can show key images side by side for comparison, and an examination to evaluate learning objectives. The program can be used as a stand-alone teaching module, a supplement to traditional instruction, a source for continuing education, or as a reference.

Computer-Assisted Instruction↗
PubMed1983

Intertrochanteric fractures: a comparison between fixation with a two-piece nail plate and Ender's nails.

The progress of 182 patients who presented with intertrochanteric fractures was followed over a six month period. Eighty-seven patients were treated using Thornton/McLaughlin nail plates and 95 were treated using Ender's intramedullary nails. Each fracture was classified according to radiological position and mechanical stability. The results show that the more unstable fractures are more likely to develop unsatisfactory results. Post operatively, the different mechanical complications have been recorded at various stages. Those fractures fixed with a nail plate tended to develop varus deformity resulting from either bony collapse around the implant or implant failure, whereas those fixed with Ender's nails did not develop deformity at the fracture site but encountered distal migration of the nails at the knee. The use of a classification system in predicting post operative mechanical complications is considered, and the comparative merits and disadvantages of the two fixation systems is discussed, with suggestions for improvement in operative technique.

Aged↗
PubMed1984

Callus characteristics following intramedullary nailing with stainless steel or epoxy-carbon nails.

Biological mechanical improvements of osteosynthesis make intramedullary nailing an attractive alternative to bone plate fixation. However, little is known about stress shielding induced by intramedullary implantation of a nail. To evaluate the effect of the nail rigidity on bone healing, mid-metatarsal osteotomies were performed in sheep and fixed with either stainless steel or epoxy-carbon composite V-shaped nails. Mechanical and histomorphometric features of the callus were evaluated 4 months postoperatively. No statistical difference between the two groups were demonstrated for either mechanical or microstructural characteristics. The presence of a fibrous membrane filling the bone/nail interface and allowing sliding micromotions of the implants and the much smaller effect of nail rigidity, as compared to bone plate after implantation, were assumed to be the main reason for this uniformity. At this stage of healing, bone characteristics were more related to a nonspecific (vascular) bone remodeling phenomenon than to a stress-shielding effect.

Animals↗
PubMed1985

[Defective shaft positioning in medullary nailing as a result of play of the nail--a biomechanical analysis].

The influence of the nail wall thickness on the stress distribution is shown for the AO-nail as well as the Küntscher-nail. The quality of the analytical solution is proved by demonstrating that the presence of the slot in the nail does not shift the bending stresses merely. The gap between nail and bone is shown to be responsible for misalignments in the fracture.

Biomechanical Phenomena↗