Osteoblast response (initial adhesion and alkaline phosphatase activity) following exposure to a barrier membrane/enamel matrix derivative combination.

BACKGROUND AND OBJECTIVE: The enamel matrix derivative (EMD) has been used in combination with barrier membranes to optimize regeneration in vertical osseous defects. However, the osteoblast response when exposed to the EMD/barrier membrane combination has not yet been evaluated. The osteoblast behavior when exposed to a combination of regenerative materials must be evaluated to fully understand their effect on bone regeneration. Therefore, the present study was undertaken to estimate the initial adhesion and alkaline phosphatase (ALP) activity of an osteoblast cell line (SaOS-2) when exposed to four commercially available resorbable membranes and determine if the addition of EMD had any modulatory effect on osteoblast behavior. MATERIALS AND METHODS: 5 x 104 SaOS-2 cells between passages 7-10 were cultured in two 24-well culture plates. Plate A was used for the adhesion assay and Plate B was used for the ALP assay. A MTT (3-[4, 5-dimethylthiazolyl-2]-2, 5-diphenyltetrazolium bromide) assay was done after 24 hours to determine the adhesion of the osteoblastic cells to four barrier membranes: 1) a non cross-linked porcine Type I and III collagen membrane (BG), 2) a weakly cross-linked Type I collagen membrane (HG), 3) a glutaraldehyde cross-linked bovine Type I collagen (BM), and 4) a resorbable polymer membrane (CP). Osteoblast differentiation was studied using an ALP assay with p-nitro phenyl phosphate as the substrate at 24 hours, 72 hours, and 1 week. A total of 50 microg/ml of EMD dissolved in 10 mM acetic acid was added into each well and the entire experimental protocol outlined above was repeated. RESULTS: The osteoblast adhesion to collagen barriers showed a statistically insignificant reduction following the addition of EMD. Adhesion to the polymer barrier, although significantly lower when compared with collagen barriers, was unaffected by the addition of EMD. ALP activity after 1 week among the various groups was as follows: EMD alone (75.59+/-2.5)>EMD/BG(64.78+/-3.04)>EMD/HG(55.40+/-3.89) approximately EMD/BM(54.75+/-4.17)>BG (51.32+/-2.76)>HG(49.92+/-2.4)>BM(48.14+/-1.4)>Control(46.29+/-1.39)>EMD/CP (37.46+/-3.54)>CP(32.12+/-1.49) CONCLUSION: There was no additive effect on osteoblast adhesion/ALP activity following exposure to an EMD/polymer combination. EMD/collagen positively influences osteoblast differentiation in a time dependent manner.

A general review of competition genetic effects with an emphasis on swine breeding

A review of previous studies is presented on estimates of genetic parameters and responses to selection with traditional breeding approaches, on correlations between agonistic behavior and growth performance, and on theoretical frameworks for selection incorporating interactions among individuals and on practical methods for incorporating competition effects in breeding programs.

Le traitement traditionnel de l'ulcere de Buruli au Benin

The purpose of this tra n s ve rs ve qualitat ive study on traditional treatment for Buruli ulcer in Benin was to track the tre atment itinera ry of pat i e n s ; the main phases of traditional treatment; cost and effi c a cy of such tre atment ; and the knowledge and skills of traditional practitioners. A total of 20 traditional practitioners; 35 patients treated by traditional therapy; and 35 patients treated by surgery were included. Findings showed that both traditional and surgical treatment was sought at a late stage. Reasons determining the type of tre atment chosen included religion; access to adequate care facilities; constraints involved in surgical treatment; duration of hospitalization; and fear of scarring. The four main steps in traditional treatment were diagnosis; removal of necrotic tissue; wound care; and exorcism. The cost of traditional treatment was high not only in c u rre n cy but also by payment in kind (e.g.; live s t o ck and land). Although it is perfo rmed with patient consent; t raditional tre atment presents a number of risks. Information campaigns are necessary to inform populations about available treatments and the possible risks associated with each modality. Care centers must do more to lessen the constraints involved in surgical treatment both in terms of duration of hospitalization and cosmetic outcome

Carbon monoxide: from toxin to endogenous modulator of cardiovascular functions

Carbon monoxide (CO) is a pollutant commonly recognized for its toxicological attributes, including CNS and cardiovascular effects. But CO is also formed endogenously in mammalian tissues. Endogenously formed CO normally arises from heme degradation in a reaction catalyzed by heme oxygenase. While inhibitors of endogenous CO production can raise arterial pressure, heme loading can enhance CO production and lead to vasodepression. Both central and peripheral tissues possess heme oxygenases and generate CO from heme, but the inability of heme substrate to cross the blood brain barrier suggests the CNS heme-heme oxygenase-CO system may be independent of the periphery. In the CNS, CO apparently acts in the nucleus tractus solitarii (NTS) promoting changes in glutamatergic neurotransmission and lowering blood pressure. At the periphery, the heme-heme oxygenase-CO system can affect cardiovascular functions in a two-fold manner; specifically: 1) heme-derived CO generated within vascular smooth muscle (VSM) can promote vasodilation, but 2) its actions on the endothelium apparently can promote vasoconstriction. Thus, it seems reasonable that the CNS-, VSM- and endothelial-dependent actions of the heme-heme oxygenase-CO system may all affect cardiac output and vascular resistance, and subsequently blood pressure

Evaluation of the optimal inoculation of leishmania major culture-derived stationary phase promastigotes required to assess protective immune status in the vervet monkey model

"Vervet monkeys have been shown to be resistant to a homologous challenge of Leishmania major after an active infection followed by self cure responses. Confirmation of the protective immune status of such animals was demonstrated by exposing a group of 4 monkeys to multiple infected sandfly challenge. Two animals revealed small transient nodule formation while in the remaining two; no signs or symptoms were obvserved. In order to ascertain the level of promastigote challenge which was equivalent to such a ""natural"" fly challenge; 3 additional groups of immune vervet monkeys were challenged with 1x103; 1x104 and 105 stationary phase culture promastigotes in the presence of salivary gl and lysates. In all groups; there was no lesion development whatsoever. A second challenge of 1x106; 1x107 and 4x107 in these same animal groups; revealed self healing nodules in the group inoculated with 1x106 promastigotes whilst in the remaining 2 groups challeged at the higher levels; there was nodule formation which progressed to ulceration. A challenge dose of 1x105 culture promastigotes was thus considered to be optimal since this level of challenge in naive animals was demonstrated to result in ulcer formation when inoculated with salivary gland lysates."

Identification of Phlebotomine Sandfly Bloodmeals from Baringo District; Kenya; by Direct Enzyme-Linked Immunosorbent Assay (ELISA)

Direct enzyme-linked immunosorbent assay (ELISA) was used to identify the sources of 356 phlebotomine sandfly bloodmeals from Baringo District; Rift Valley Province; Kenya. Some bloodmeals had been stored for over 4 years before being analysed. Of the 356 sandflies; 62.9 were phlebotomus martini; 14.8 Sergentomyia antennatus; 10.0 S. schwetzi; 6.0 S. clydei; 1.9 S. adleri; 1.6 P. duboscqi; 1.4 S. africanus; and 0.8 S. bedfordi. Out of 224 P. martini bloodmeals; host source was identified for 69. The order of host prefernce for P. martini was: goat 28.5; rabbit 22.7 human 8.9 and other 8.9. Evidence of mixed feeding was shown by 16 sandflies comprising 4 species; 12 of these were P. martini. The most effective methods for trapping bloodfed P. martini; were sticky paper traps in termite hills; followed by light-traps. Of the 224 P. martini trapped; 58.9 were collected with paper traps in termite hills; and 22.7 with light traps. The role played by the 3 most popular hosts for P. martini should be investigated to ascertain whether they act as reservoirs in the transmission of visceral leishmaniasis in Kenya

Use of 99mTc-sulfur colloid to assess lymphatic dysfunction in filarial infection.

Investigations of lymphatic dysfunction in animals infected with filarial parasites has been hampered by a paucity of techniques to measure efficiency of lymphatic drainage. In this study a 99mTc-sulfur colloid technique was used to assess the efficiency of lymphatic drainage in Patas monkeys infected with filarial nematodes. In all 15 uninfected hind limbs there was rapid and consistent appearance of labeled colloid in the primary lymph node (popliteal) and subsequently in the secondary nodes (abdomino-pelvic) in 11 of 15 limbs. In contrast, in all eight limbs tested 1-9 months after infection there was reduced rate of migration of the colloid and initial appearance in the abdomino-pelvic region: subsequent accumulation was seen in the popliteal region in only four of the limbs. This data indicated that lymphatic vessels were blocked and that collateral vessels channeled the colloid to the secondary lymph nodes. The lymph flow patterns demonstrated by the isotope technique were supported at autopsy.