Influence of Bioactive Glass and/or Acellular Dermal Matrix on Bone Healing of Surgically Created Defects in Rat Tibiae: A Histological and Histometric Study

The purpose of this study was to histologically analyze the influence of bioactive glass and/or acellular dermal matrix on bone healing in surgically created defects in the tibiae of 64 rats (Rattus norvegicus, albinus, Wistar). Materials and Methods: A 4-mm X 3-mm unicortical defect was created on the anterolateral surface of the tibia. Animals were divided into 4 groups: C, control; BG, the defect was filled with bioactive glass; ADM, the defect was covered with acellular dermal matrix; and BG/ADM, the defect was filled with bioactive glass and covered with acellular dermal matrix. Animals were sacrificed at 10 or 30 days postoperatively, and the specimens were removed for histologic processing. The formation of new bone in the cortical area of the defect was evaluated histomorphometrically. Results: At 10 and 30 days postoperatively, groups C (39.65% +/- 5.63% / 63.34% +/- 5.22%) and ADM (38.12% +/- 5.53 / 58.96% +/- 7.05%) presented a larger amount of bone formation compared to the other groups (P<.05). In the same periods, groups BG (13.10% +/- 6.29% / 29.5% +/- 5.56%) and BG/ADM (20.72% +/- 8.31% / 24.19% +/- 6.69%) exhibited statistically similar new bone formation. However, unlike the other groups, group BG/ADM did not present a significant increase in bone formation between the 2 time points. Conclusion: Based on these results, it can be concluded that all of the materials used in this study delayed bone healing in non-critical-size defects. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:811-817

Análise histológica em tecido epitelial sadio de ratos Wistar (in vivo) irradiados com diferentes intensidades do ultrassom

CONTEXTUALIZAÇÃO: O Ultrassom (US) é um dos recursos físicos amplamente utilizado e pesquisado nos tratamentos de fisioterapia. Sabe-se que diante de uma escassa literatura sobre efeitos do US em tecidos sadios, muitos profissionais fisioterapeutas acabam realizando aplicações infundadas de métodos e parâmetros. OBJETIVO: Avaliar possíveis alterações histológicas e morfométricas do tecido sadio in vivo de ratos Wistar irradiados com diferentes intensidades de US. MÉTODOS: Trinta ratos da linhagem Wistar, distribuídos aleatoriamente em cinco grupos de seis animais cada foram tratados na região dorsal do lado direito numa área de 4cm². O lado esquerdo serviu como controle. O tratamento foi feito durante quatro dias com 2 minutos de irradiação. Verificou-se a intensidade de saída com dosímetro de precisão antes das aplicações. Analisou-se a histologia e a morfometria por meio do software Image Tool. RESULTADOS: Observou-se um discreto infiltrado inflamatório e adelgaçamento das fibras da derme, principalmente dos grupos irradiados com 1.5 e 2W/cm². Notou-se também um aumento na espessura da epiderme nas amostras dos animais irradiados. Para avaliar os resultados quantitativos, utilizou-se como análise estatística ANOVA one way e o teste post hoc de Tukey. Na espessura da epiderme, obtiveram-se diferenças significativas entre grupo controle e os grupos irradiados com 1.0, 1.5 e 2.0W/cm². CONCLUSÃO: Sob ação do US nas doses maiores houve alterações na epiderme e derme, respectivamente, o aumento da espessura e proliferação com adelgaçamento das fibras colágenas, o que alerta para possíveis implicações do uso do US em estética.

S-100 dendritic cells in normal and Dermatobia hominis infested cattle skin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The inguinal macroglands of the frog Physalaemus nattereri (Leptodactylidae): structure, toxic secretion and relationship with deimatic behaviour

Amphibian skin is characterized by the presence of mucous glands, related to cutaneous breathing, reproduction and water balance, and granular glands, related to the production of toxins used in defence. In some species the granular glands can form accumulations in certain regions of the body. This is the case for inguinal macroglands of the leptodactylid frog Physalaemus nattereri, where these structures form a pair of black discs associated with deimatic behaviour. The morphology of the inguinal macroglands and their secretion were studied in this species and correlated to deimatic behaviour. The inguinal macroglands are formed from elongated granular glands that, in contrast with the granular glands of the rest of the skin, have small spherical granules with a proteinic content. In the dermis of the whole body, except for the inguinal macroglands and the inguinal region, a well-developed calcified dermal layer is observed. During deimatic behaviour these macroglands discourage a potential predator from attacking, but if visual cues are insufficient and the predator persists in the attack, atoxic secretion is eliminated in its mouth. This elimination is favoured by the absence of a calcified dermal layer in the macroglands, which makes the dermal region softer than the rest of the dorsal skin.

Histopathology of tick-bite lesions in naturally infested capybaras (Hydrochoerus hydrochaeris) in Brazil

In the present work features of tick-bite lesions were evaluated in capybaras naturally infested with Amblyomma cajennense and Amblyomma dubitatum ticks. Gross appearance of tick bite site was characterized by a mild swelling and erythema. Microscopic examination revealed the cement cone, a tube-like homogenous eosinophilic mass penetrating deep into the dermis. This structure was surrounded in the dermis by a cellular infiltrate and free eosinophilic granules and was associated to edema of variable intensity. Necrosis was a common feature deep in the dermis particularly at the far end of the eosinophilic tube. Hyperplasia, cellular edema and occasionally necrosis of keratinocytes could be seen at both sides of the ruptured epidermis. Cellular infiltrate was constituted overwhelmingly by polymorphonuclear leukocytes with eosinophilic granules. In capybaras cells with such features can be either eosinophils or heterophils (pseudoeosinophils), the latter being the equivalent of neutrophils of other mammals. Ultrastructural analysis of the cellular infiltrate revealed the predominance of heterophils over eosinophils. Mononuclear cells and mast cells and, in lesser numbers, basophils were also seen at skin attachment sites. The presence of heterophils in the reaction of capybaras against Amblyomma ticks is an outstanding feature but its role in the reaction to the tick is not known. It is however speculated that capybara heterophils might be associated with a more permissive environment for tick feeding and pathogen transmission as already shown for the equivalent cell type, the neutrophil, in the reaction of the dog against the Rhipicephalus sanguineus tick.

Dermal mast cell counts in F2 Holstein x Gir crossbred cattle artificially infested with the tick Boophilus microplus (Acari : Ixodidae)

The role of dermal mast cells (DMC) in the host resistance to ticks has been studied but it is not totally explained yet. Studies have proposed that zebuine cattle breeds, known as highly resistant to ticks, have more DMC than taurine breeds. In the present study, we compared the number of adult female ticks Boophilus microplus and the mast cells' countings in the skin of F-2 crossbred Gir x Holstein cattle, before and after tick infestation. F-2 crossbred cattle (n = 148) were divided into seven groups and artificially infested with 1.0 x 10(4) B. nticroplus larvae and, 21 days afterwards, adult female-fed ticks attached to the skin were counted. Skin biopsies were taken and examined under light microscopy with a square-lined ocular reticulum in a total area of 0.0625 mm(2) in both the superficial and deep dermis. Results demonstrated that infested F-2 crossbred cattle acquired resistance against the cattle-tick B. microplus probably associated to an increase in the dermal mast cell number. It is concluded that the tick infestation may lead to an environmental modification in the dermis of parasitized hosts due to the massive migration of mast cells or their local proliferation.

Hereditary equine regional dermal asthenia in three related Quarter horses in Brazil

Hereditary equine regional dermal asthenia belongs to a group of inherited, congenital connective tissue dysplasias usually described as hyperelastosis cutis, cutaneous asthenia, dermatosparaxis, or Ehlers-Danlos-like syndrome. This report presents the clinical and histological features of three related Quarter horses affected with regional dermal asthenia. These horses had bilateral asymmetric lesions of the trunk and lumbar regions, where the skin was hyperextensible. Handling of the skin elicited a painful response and superficial trauma led to skin wounds. The skin was thinner than normal in the affected areas, with thickened borders and harder fibrotic masses (pseudotumours). The histopathological findings included thinner and smaller collagen fibrils, and a loose arrangement of collagen fibres in the middle, adventitial and deep dermis. Masson's trichrome and Calleja stains did not reveal any abnormality of collagen and elastic fibres. Electron microscopy showed no abnormalities. As in human patients, pseudotumour histopathological findings included fibroplasia and neovascularization. The pedigree chart of these animals supports an autosomal recessive type of inheritance, which has been suggested by other studies. This is the first report of this disease in Brazil. Its clinical and histological features resemble those described in horses affected with this condition in the United States.

Expression of human leucocyte antigen-G primarily targets affected skin of patients with psoriasis

P>BackgroundThe nonclassical human leucocyte antigen (HLA)-G molecule has been well recognized as a tolerogenic molecule and few studies have evaluated the role of the molecule in inflammatory cutaneous autoimmune diseases.ObjectivesTo evaluate the expression of HLA-G in skin specimens of patients with psoriasis and to analyse its correlation with epidemiological and clinical variables.MethodsThirty untreated patients with psoriasis and 32 healthy individuals were enrolled. Immunohistochemistry was applied to identify HLA-G expression in formalin-fixed paraffin-embedded cutaneous skin biopsies.ResultsSoluble and membrane-bound HLA-G expression was detected in 30 (90%) of the skin specimens from patients presenting clinical and histopathological features of psoriasis. Although infiltrating lymphomononuclear cells of the dermis exhibited HLA-G expression, the epidermis was primarily targeted. HLA-G expression was also observed in 27% (three of 11) of the specimens that exhibited no clinical and histopathological features of psoriasis (nonaffected areas). In contrast, skin specimens obtained from healthy individuals exhibited no HLA-G expression (P < 0 center dot 0001). The intensity of HLA-G expression was not associated with type I/II psoriasis, Psoriasis Area and Severity Index score or clinical forms.ConclusionsAs the HLA-G molecule was consistently expressed in affected and, to a lesser extent, in nonaffected areas of untreated patients with psoriasis, irrespective of the severity of the clinical variants, one may hypothesize that the presence of HLA-G may be responsible, at least in part, for the regulation of autoimmune effector cells.

The fine structure of the swine sweat gland. II. The coiled ducts

The duct of the swine sweat gland crosses the dermis and epidermis in sequence. The cells of the dermic segment seem to be related with cellular secretion and absorption. In the epidermic segment of the duct the whole morphology of the cells resembles the cellular morphology of the epidermic cells.

Rhabdomyosarcoma in a congenital pigmented nevus

A 7-month-old boy had a giant pigmented lesion involving the trunk and thighs that exhibited many hyperpigmented hairy and verrucous nevi. One of the nevi ulcerated and on histological examination consisted of pleomorphic rhabdomyosarcoma cells that stained for muscle-specific actin (HHF-35), desmin, and myoglobin. Around the tumor, in the dermis, benign pigmented nevus cells were observed. The occurrence of malignant tumors, other than malignant melanoma, in pigmented nevi is rarely described.

Acellular dermal tissue study: an ultrastructural evaluation of human and porcine derived tissues in a rat model

The purpose of this study was to evaluate the host response of a human and a porcine derived acellular dermal tissue (ADT) implanted in the subcutaneous tissue of a rat model. Two subcutaneous pockets were surgically created along the dorsal midline of 25 rats (5 rats/group). The human ADT was placed superiorly and the porcine ADT, inferiorly. The animals were sacrificed at 07, 15, 30, 60 and 180 postoperative days (PO) and the ADTs and surrounding soft tissues were assessed for ultrastructural evaluation by transmission electron microscopy. The ultrastructural findings were similar in both materials. Normal collagen and elastic fibers bundles were observed during all experimental moments, as well as macrophages presenting cytoplasmic enlargements digesting cellular portions after 15 PO. From 30 until 180 PO, vacuolar structures filled with an amorphous, electron-transparent substance, were present inside and outside the fibroblasts. Both human and porcine ADT showed similar pattern of ultrastructural response when implanted in the subcutaneous tissue of rats. The porcine ADT appears as a good alternative to be used as a biomaterial.

A comparison of human and porcine acellular dermal tissues in the subcutaneous space of a rat model

The study compared the host response to a human and a porcine acellular dermal tissue implanted in the subcutaneous space of a rat model. The human and porcine acellular grafts were surgically implanted in the subcutaneous tissue of rats (5 rats/group) and the materials were evaluated at 7, 15, 30, 60 and 180 postoperative days (PO). The histological immune response was quantified using a digital image analysis system, which evaluated the number of vessels present in the implants and in the surrounding soft tissue, the area of inflammatory cell infiltration in the grafts, the width of the capsular formation present around the tissues and the area of implants absorbed. The data were submitted to statistical analysis. Light microscopy showed mononuclear cellular infiltration, the presence of a capsular formation surrounding the grafts and the presence of vacuolar structures (optically empty spaces) inside the implants. The image analysis comparing both materials showed significant inflammatory cells in the human graft at 15 and 30 PO, thicker capsular formation in the porcine tissue at 60 PO, increased number of vessels inside the implants and in the surrounding tissues in the porcine graft and a similar absorption pattern in both materials at 180 PO. The histological findings showed that both tissues were well-tolerated when implanted in the subcutaneous tissue of rats, allowing us to consider the porcine acellular dermal graft as a provisional alternative material for reconstructive plastic surgery. Copyright © 2005 Taylor & Francis LLC.

Effect of collagenase ointment on a radiofrequency induced abrasive wound

• Aim: Radiofrequency is one of the methods used to treat wrinkles and skin lesions, but its application may result in an abrasive wound. The purpose of this study was to evaluate the effect of collagenase ointment on the epithelial healing of an abrasive wound induced by a radiofrequency system. • Methods: An abrasive wound was produced using radiofrequency at the dorsal midline of 30 guinea pigs, which were randomly divided into 2 groups: one group were treated with saline solution and the other group treated with collagenase ointment; both used twice daily. The animals were sacrificed at 1, 7, 15, 30 and 60 postoperative days. Macroscopic, histological and morphometric evaluations were performed and the results were submitted to statistical analysis. • Results: The animals treated with collagenase ointment presented accelerated healing process and less inflammatory cell infiltration than the saline solution treated animals from one to fifteen postoperative days. Morphometric evaluation showed a thicker epidermis and a thinner dermis layer in the saline solution group at one and seven postoperative days, but significant differences between both groups were not observed at thirty and sixty postoperative days. • Conclusion: According to our results the use of collagenase ointment may accelerate the healing process of a radiofrequency induced abrasive wound.

Evaluation of skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion

Several dermocosmetic bases even without active substances, can increase the cutaneous hydration, resulting in a beneficial effect to the skin. The evidence and interpretation of possible hydration effect of formulations in the skin can be carried through by means of histopathological and histomorphometrical evaluation, a time that allows the analysis of the epithelial tissue, of dermis and also of the cellular characteristics. The objective of this research was to evaluate the skin hydration after exposition to the aqueous and hydroalcoholic bases and silicone emulsion. Swines had areas submitted to treatments during 15 days with three different formulations (F1 - aqueous gel, F2 - hydroalcoholic gel and F3 - silicone emulsion). By means of histometric and histopathological techniques were gotten the thickness of the epidermis and stratum corneum. Comparison of means was done using ANOVA followed by the Tukey test. The F1 provoked significant increase in the thickness of the epidermis. The formulaton F2 provoked significant reduction in the thickness of the epidermis and stratum corneum. F3 not presented significant difference in this structures. According to the study, the type of base chosen intervenes with the skin hydration.

Influence of apoptosis on the cutaneous and peripheral lymph node inflammatory response in dogs with visceral leishmaniasis

In canine visceral leishmaniasis (CVL), the abnormalities most commonly observed in clinical examination on the animals are lymphadenomegaly and skin lesions. Dogs are the main domestic reservoir for the protozoon Leishmania (L.) chagasi and the skin is the main site of contamination by the vector insect. Some protozoa use apoptosis as an immunological escape mechanism. The aim of this study was to correlate the presence of apoptosis with the parasite load and with the inflammatory response in the skin and lymph nodes of dogs naturally infected with Leishmania (L.) chagasi. Thirty-three dogs from the municipality of Araçatuba (São Paulo, Brazil) were used, an endemic area for CVL. Muzzle, ear and abdominal skin and the popliteal, subscapular, iliac and mesenteric lymph nodes of symptomatic (S), oligosymptomatic (O) and asymptomatic (A) dogs were analyzed histologically. The parasite load and percentage apoptosis were evaluated using an immunohistochemical technique. Microscopically, the lymph nodes presented chronic lymphadenitis and the skin presented plasmacytic infiltrate and granulomatous foci in the superficial dermis, especially in the ear and muzzle regions. The inflammation was most severe in group S. The parasite load and apoptotic cell density were also greatest in this group. The cause of the lymphoid atrophy in these dogs was correlated with T lymphocyte apoptosis, thus leaving the dogs more susceptible to CVL. The peripheral lymph nodes presented the greatest inflammatory response. Independent of the clinical picture, the predominant inflammatory response was granulomatous and plasmacytic, both in the skin and in the peripheral lymph nodes. The ear skin presented the greatest intensity of inflammation and parasite load, followed by the muzzle skin, in group S. The ear skin area presented a non-significant difference in cell profile, with predominance of macrophages, and a significant difference from group A to groups O and S. It was seen that in these areas, there were high densities of parasites and cells undergoing apoptosis, in group S. The association between apoptosis and parasite load was not significant in the lymph nodes, but in the muzzle regions and at the ear tips, a positive correlation was seen between the parasite load and the density of cells undergoing apoptosis. The dogs in group S had the highest parasite load and the greatest number of apoptotic cells, thus suggesting that the parasite had an immune evasion mechanism, which could be proven statistically in the skin. © 2012 Elsevier B.V.