Polyurethane and PTFE membranes for guided bone regeneration: Histopathological and ultrastructural evaluation

Objective: The purpose of this study was to research a membrane material for use in guided bone regeneration. Study design: In this study, 25 male Wistar rats were used to analyze the biocompatibility and degradation process of biomembranes. The morphological changes in subcutaneous implantations were assessed after 7, 14, 21, 28 and 70 days. The materials were made of polyurethane polymer (AUG) obtained from vegetal oil (Ricinus communis) and polytetrafluoroethylene membrane (PTFE). The surface characteristics of the physical barriers in scanning electronic microscopic (SEM) were also evaluated. Results: In both groups, the initial histological analysis showed moderate inflammatory infiltrate, which was predominantly polymorphonuclear. There was also a presence of edema, which was gradually replaced by granulation tissue, culminating in a fibrous capsule. In the AUG group, some multinucleated giant cells were present in the contact interface, with the space previously occupied by the material. However, membrane degradation was not observed during the period studied. According to the present SEM findings, porosity was not detected in the AUG or PTFE membranes. Conclusion: The researched material is biocompatible and the degradation process is extremely slow or may not even occur at all.

Biocompatibility of a chlorhexidine local delivery system in a subcutaneous mouse model

Objective: This study aimed evaluating histologically and histomorphometrically the response of the conjunctive tissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. Study Design: In this research 35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip. In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and a polytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations were assessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze the comparisons among observation periods and to allow the comparison among groups. Results: Differences were found in the analysis of the inflammatory response when comparing the tested materials (p values <= 0.05). In test group was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic around material. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From 10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagic infiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observed initially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatory infiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cells situated at contact interface with the coating was examined since 3-day and persisted until 21-day. Conclusion: The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore, at conditions of this study was not biocompatible.

Época de colheita e capacidade germinativa de sementes de Tibouchina mutabilis (Vell.) Cogn. (Melastomataceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Description and relationships of Otothyropsis marapoama, a new genus and species of hypoptopomatine catfish (Siluriformes: Loricariidae) from rio Tietê basin, southeastern Brazil

Otothyropsis marapoama, novo gênero e espécie, é descrito baseado em espécimes recentemente coletados em um riacho de cabeceira da porção media do rio Tietê, um rio da bacia do alto rio Paraná no sudeste do Brasil. O novo táxon pertence a um clado que inclui também os gêneros Schizolecis, Otothyris e Pseudotothyris. Otothyropsis marapoama é considerado o grupo-irmão de Pseudotothyris e Otothyris baseado principalmente na presença de vários caracteres derivados da cápsula da bexiga natatória e ossos associados. Vários caracteres pedomórficos compartilhados por Pseudotothyris e Otothyris e seu significado filogenético para a posição deste novo gênero são discutidos.

RADIOGRAFIA E MACROSCOPIA do JOELHO APÓS ESTABILIZAÇÃO EXTRA-ARTICULAR UTILIZANDO FÁSCIA LATA, FIO DE POLIÉSTER TRANÇADO OU FIO DE POLIAMIDA PARA CORREÇÃO da RUPTURA do LIGAMENTO CRUZADO CRANIAL em CÃES

A ruptura do ligamento cruzado cranial é uma das principais doenças ortopédicas que afetam os cães. Muitas técnicas cirúrgicas foram descritas no intuito de aliviar a dor, restaurar a estabilidade biomecânica do joelho e prevenir a progressão da osteoartrite. Fáscia lata, fio de poliéster trançado e fio de poliamida foram empregados na estabilização do joelho após excisão do ligamento cruzado cranial em cães, os quais foram submetidos à avaliação radiográfica e macroscópica da articulação. Neste estudo, foram utilizados 18 cães com massa corporal superior a 15Kg (peso médio - 19,67kg), separados em 3 grupos eqüitativos correspondentes a cada técnica, avaliados durante 30 e 60 dias. Ao exame radiográfico, independentemente de grupo, os cães apresentaram evidência de efusão articular moderada a severa, distensão da cápsula articular e, na maioria dos casos, ausência de sinais de doença articular degenerativa. Ao exame macroscópico da articulação do joelho observou-se espessamento da cápsula articular e tecidos moles periarticulares, erosão da cartilagem articular dos côndilos femorais em todos os grupos e afrouxamento dos fios nos cães submetidos às técnicas de estabilização extra-articular com fio de poliéster trançado e fio de poliamida.

Lipossarcoma esplênico em um cão

O presente trabalho visa relatar um caso de lipossarcoma canino, por se tratar de uma rara neoplasia em cães. Um cão, fêmea, Fila Brasileiro, 9 anos de idade com 47kg apresentou anorexia, vômito e apatia. A palpação abdominal revelou massa na região mesogástrica, e o paciente morreu antes da celiotomia exploratória. À necrópsia, constatou-se massa medindo 10 x 10 x 13cm aderida ao baço. O diagnóstico histológico foi lipossarcoma.

Virulence Factors IN Fungi of Systemic Mycoses

Fatores de virulência em fungos de micoses sistêmicaFungos patogênicos causadores de micoses sistêmicas possuem vários fatores que permitem seu crescimento nas condições adversas oferecidas pelo hospedeiro, propiciando o estabelecimento da relação parasitária e contribuindo no processo de doença. Esses fatores são conhecidos como fatores de virulência auxiliando no desenvolvimento da infecção e interferindo com a patogênese das micoses. O presente trabalho avalia os fatores de virulência em fungos patogênicos como Blastomyces dermatitidis, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum e Paracoccidioides brasiliensis, em relação à termotolerância, dimorfismo, componentes da parede celular ou cápsula, bem como a produção de enzimas. Os fatores de virulência auxiliam na aderência, colonização, disseminação e habilidade do fungo para resistir a ambientes hostis e escapar dos mecanismos da resposta imune do hospedeiro.Tanto os fatores de virulência apresentados por diferentes fungos, como os mecanismos de defesa oferecidos pelo hospedeiro requerem ação e interação de processos complexos, cujo conhecimento permitirá a melhor compreensão da patogenia das micoses sistêmicas.

Evaporative cooling and cutaneous surface temperature of Holstein cows in tropical conditions

Foram estudados os efeitos da temperatura cutânea (Ts) sobre a taxa de termólise por evaporação cutânea (Es) de vacas Holandesas cronicamente expostas ao sol, considerando a pigmentação do pelame. Dezesseis vacas puras de origem foram medidas quanto à evaporação e à temperatura cutâneas às 13 h, após 6 horas de exposição ao sol, no mesmo local (flanco, pescoço e glúteo) e considerando separadamente as malhas negras e as brancas. A evaporação cutânea foi medida por meio de cápsula ventilada. Nas áreas negras a taxa de sudação (138,9 ± 8,5 g.m-2.h-1), a taxa de termólise por evaporação cutânea (93,3 ± 5,7 W.m-2) e a temperatura da superfície cutânea (33,1 ± 0,2°C) foram maiores que nas áreas brancas (109,5 ± 9,7 g.m-2.h-1, 73,6 ± 6,5 W.m-2 e 32,6 ± 0,2°C, respectivamente). Há uma relação exponencial entre evaporação e temperatura cutâneas, que pode ser representada pela equação Es = 31,5+3,67 exp{(Ts-27,9)/2,19115}, com coeficiente de determinação r²=0,68. A taxa de termólise por evaporação cutânea permanece quase constante (cerca de 48 W.m-2) até que a temperatura cutânea atinge aproximadamente 31°C.

Glycosaminoglycans in components of the rabbit eye: synthesis and characterization

Purpose. To trace the eye components involved in proteoglycan synthesis and to characterize the sulfated glycosaminoglycans which are associated to these macromolecules.Methods. Sodium [S-35]-sulfate was injected intravitreally and the rabbits were killed at different time intervals after the injection. The glycosaminoglycans of choroid, ciliary body, cornea, iris, lens capsule, retina and sclera were extracted and processed for estimations of their specific activities, and for electrophoresis plus autoradiography with or without previous treatment with specific enzymes. In addition, methacrylate sections of the eyes were analysed by autoradiography.Results. The peak of specific activities of the glycosaminoglycans of all eye components occurred at 2 days after the intravitreal injection of [S-35]-sulfate. The autoradiography of the agarose gels revealed three types of glycosaminoglycans, namely, heparan-, chondroitin- and dermatan sulfate, only in the retina. The other eye components contained heparan sulfate and either chondroitin or dermatan sulfate. Tissue autoradiography together with the biochemical techniques contributed to unravel the origin of the glycosaminoglycans in the eye components.Conclusions. The results of the present investigation have shown that heparan sulfate, contrasting to chondroitin sulfate and dermatan sulfate, is synthesized in all eye components studied and that the glycosaminoglycan composition differs according to the tissue of origin.

Sensible and latent heat loss from the body surface of Holstein cows in a tropical environment

The general principles of the mechanisms of heat transfer are well known, but knowledge of the transition between evaporative and non-evaporative heat loss by Holstein cows in field conditions must be improved, especially for low-latitude environments. With this aim 15 Holstein cows managed in open pasture were observed in a tropical region. The latent heat loss from the body surface of the animals was measured by means of a ventilated capsule, while convective heat transfer was estimated by the theory of convection from a horizontal cylinder and by the long-wave radiation exchange based on the Stefan-Boltzmann law. When the air temperature was between 10 and 36 degrees C the sensible heat transfer varied from 160 to -30 W m(-2), while the latent heat loss by cutaneous evaporation increased from 30 to 350 W m(-2). Heat loss by cutaneous evaporation accounted for 20-30% of the total heat loss when air temperatures ranged from 10 to 20 degrees C. At air temperatures > 30 degrees C cutaneous evaporation becomes the main avenue of heat loss, accounting for approximately 85% of the total heat loss, while the rest is lost by respiratory evaporation.

Effect of pancreas transplantation on the prevention of nephropathy in alloxan-induced diabetic rats

We studied the effects of pancreas transplantation on kidney lesions of rats with alloxan-induced diabetes. Ninety inbred male Lewis rats were randomly assigned to 3 experimental groups: group NC included 30 non-diabetic control rats, group DC included 30 alloxan-induced diabetic control rats, and group PT included 30 alloxan-induced diabetic rats that received pancreas transplants from normal donor Lewis rats. Each group was further divided into 3 subgroups of 10 rats which were sacrificed at 1, 3, and 6 months of follow-up, respectively. Clinical and laboratory parameters during these periods were documented. The kidneys of 5 rats in each subgroup were studied and 50 glomeruli and tubules from each kidney were analyzed by light microscopy by two different investigators in a double-blind study. There was progressive glomerular basement membrane thickening (GBMT), mesangial enlargement (ME), and Bowman's capsule thickening (BCT) in kidneys of rats in the 3 experimental groups during follow-up. These alterations were significantly higher in DC rats (GBMT: 1.99 +/- 0.31; ME: 2.00 +/- 0.33; BCT: 1.88 +/- 0.27) when compared to NC(GBMT: 1.54 +/- 0.30; ME: 1.56 +/- 0.47; BCT: 1.36 +/- 0.35) and PT rats (GBMT: 1.49 +/- 0.29; ME: 1.57 +/- 0.36; BCT: 1.35 +/- 0.28) at 6 months (P<0.01). The extent of GBMT, ME, and BCT observed in DC rats at 1 and 3 months was not significantly different from NC and PT rats. The amount of kidney lesions in PT rats was similar to that of NC rats and lower than those of DC rats at 6 months (P<0.01). In addition, Armanni-Ebstein lesions of the tubules (AE) and tubular lumen protein (PRO) observed in DC rats were not present in NC or PT rats. We conclude that pancreas transplantation in alloxan-induced diabetic rats prevents the development of kidney lesions beginning at 6 months after transplantation.

Intra-articular pressure profiles of the cadaveric equine fetlock joint in motion

The study of the influence of motion and initial intra-articular pressure (IAP) on intra-articular pressure profiles in equine cadaver metatarsophalangeal (MTP) joints was undertaken as a prelude to in vivo studies, Eleven equine cadaver MTP joints were submitted to 2 motion frequencies of 5 and 10 cycles/min of flexion and extension, simulating the condition of lower and higher (double) rates of passive motion. These frequencies were applied and pressure profiles generated with initial normal intra-articular pressure (-5 mmHg) and subsequently 30 mmHg intra-articular pressure obtained by injection of previously harvested synovial fluid.The 4 trials performed were 1) normal IAP; 5 cyles/min; 2) normal IAP; 10 cycles/min; 3) IAP at 30 mmHg; 5 cycles/min and 4) IAP at 30 mmHg; 10 cycles/min. The range of joint motion applied (mean +/- s.e.) was 67.6 +/- 1.61 degrees with an excursion from 12.2 +/- 1.2 degrees in extension to 56.2 +/- 2.6 degrees in flexion, Mean pressure recorded in mmHg for the first and last min of each trial, respectively, were 1) -5.7 +/- 0.9 and -6.3 +/- 1.1; 2) -5.3 +/- 1.1 and -6.2 +/- 1.1; 3) 58.8 +/- 8.0 and 42.3 +/- 7.2; 4) 56.6 +/- 3.7 and 40.3 +/- 4.6. Statistical analyses showed a trend for difference between the values for the first and last minute in trial 3 (0.05>P<0.1) with P = 0.1 and significant difference (P = 0.02) between the mean IAP of the first and last min in trial 4. The loss of intra-articular pressure associated with time and motion was 10.5, 16.9, 28.1 and 28.9% for trials 1-4, respectively. As initial intraarticular pressure and motion increased, the percent loss of intra-articular pressure increased.The angle of lowest pressure was 12.2 +/- 1.2 (mean +/- s.e.) in extension in trials 1 and 2, In trials 3 and 4, the lowest pressures were obtained in flexion with the joints at 18.5 +/- 2.0 degrees (mean +/- s.e.). This demonstrated that the joint angle of least pressure changed as the initial intra-articular pressure changed and there would not be a single angle of least pressure for a given joint.The volume of synovial fluid recovered from the MTP joints in trial 3 compared to 4 (trials in which fluid was injected to attain IAP of 30 mmHg) was not significantly different, supporting a soft tissue compliance change as a cause for the significant loss of intra-articular pressure during the 15 min of trial 4.The pressure profiles generated correlate well with in vivo values and demonstrated consistent pressure profiles. Our conclusions are summarised as follows:1. Clinically normal equine MTP joints which were frozen and then later thawed were found to have mostly negative baseline intra-articular pressures, as would be expected in living subjects,2. Alternate pressure profiles of the dorsal and plantar pouch at baseline intra-articular pressure document the presence of pressure forces that would support 'back and forth' fluid movement between joint compartments. This should result in movement of joint fluid during motion, assisting in lubrication and nutrition of articular cartilage,3. If joint pressure was initially greater than normal (30 mmHg), as occurs in diseased equine MTP joints, joint motion further increased joint capsule relaxation (compliance) and, therefore, reduced intra-articular pressure.4. Peak intra-articular pressures reached extremely high values (often >100 mmHg) in flexion when initial pressure was 30 mmHg. Joint effusion pressures recorded for clinical MCP joints are frequently 30 mmHg. These IAP values are expected to produce intermittent synovial ischaemia in clinical cases during joint flexion.5, Additional in vivo studies are necessary to confirm our conclusions from this study and to identify the contributions of fluid absorption and the presence of ischaemia in a vascularised joint.

Use of topical mitomycin C in myoplasty of the medial rectus muscle of rabbits

To possibly reduce postoperative adhesions that occur after ocular myoplasties, we investigated the topical effects of 0.04% mitomycin C on the repaired areas of the medial rectus muscle using an equine renal capsule preserved in 98% glycerin for reinforcement of the sutures. Twenty-four rabbits, divided into two groups of 12 animals each [untreated (control) and treated group (MMC)], were submitted to surgical rupture of the medial rectus muscle of one eye and repair of the defect 24 h later with sutures and an equine renal capsule. Post-operative prophylactic treatment of the two groups consisted of the administration of eye drops containing neomycin, polymyxin B and dexamethasone at regular 6-h intervals for eight consecutive days and daily rinsing with physiological saline. MMC animals received additional treatment with topical 0.04% mitomycin C every 6 h for 14 consecutive days. Slit lamp biomicroscopy showed greater irritation of the ocular surface in MMC animals during the first days post operatively. Adhesions were observed at 15 and 30 days of assessment in the two groups, but were more extensive in control animals at 60 days. Histopathology revealed inflammatory exudation in both groups, which was greater in MMC animals. Mitomycin C (0.04%) instilled at 6-h intervals for 14 consecutive days reduced the occurrence of fibrosis in the myoplastic areas. However, the equine renal capsule was found to be of little benefit for the reinforcement of myoplasties.

Macro- and microstructure of the superior cervical ganglion in dogs, cats and horses during maturation

The superior cervical ganglion (SCG) provides sympathetic input to the head and neck, its relation with mandible, submandibular glands, eyes (second and third order control) and pineal gland being demonstrated in laboratory animals. In addition, the SCG's role in some neuropathies can be clearly seen in Horner's syndrome. In spite of several studies published involving rats and mice, there is little morphological descriptive and comparative data of SCG from large mammals. Thus, we investigated the SCG's macro- and microstructural organization in medium (dogs and cats) and large animals (horses) during a very specific period of the post-natal development, namely maturation (from young to adults). The SCG of dogs, cats and horses were spindle shaped and located deeply into the bifurcation of the common carotid artery, close to the distal vagus ganglion and more related to the internal carotid artery in dogs and horses, and to the occipital artery in cats. As to macromorphometrical data, that is ganglion length, there was a 23.6% increase from young to adult dogs, a 1.8% increase from young to adult cats and finally a 34% increase from young to adult horses. Histologically, the SCG's microstructure was quite similar between young and adult animals and among the 3 species. The SCG was divided into distinct compartments (ganglion units) by capsular septa of connective tissue. Inside each ganglion unit the most prominent cellular elements were ganglion neurons, glial cells and small intensely fluorescent cells, comprising the ganglion's morphological triad. Given this morphological arrangement, that is a summation of all ganglion units, SCG from dogs, cats and horses are better characterized as a ganglion complex rather than following the classical ganglion concept. During maturation (from young to adults) there was a 32.7% increase in the SCG's connective capsule in dogs, a 25.8% increase in cats and a 33.2% increase in horses. There was an age-related increase in the neuronal profile size in the SCG from young to adult animals, that is a 1.6-fold, 1.9-fold and 1.6-fold increase in dogs, cats and horses, respectively. on the other hand, there was an age-related decrease in the nuclear profile size of SCG neurons from young to adult animals (0.9-fold, 0.7-fold and 0.8-fold in dogs, cats and horses, respectively). Ganglion connective capsule is composed of 2 or 3 layers of collagen fibres in juxtaposition and, as observed in light microscopy and independently of the animal's age, ganglion neurons were organised in ganglionic units containing the same morphological triad seen in light microscopy. Copyright (c) 2007 S. Karger AG, Basel.