Effect of Mouth Rinses with Fluoride and Trimetaphosphate on Enamel Erosion: An in vitro Study

The effect of mouth rinses containing fluoride (100 mu g/ml) and sodium trimetaphosphate (TMP) on enamel erosion was evaluated in vitro. Bovine enamel blocks were subjected to erosive challenges 4 times per day for 5 min, followed by treatment with placebo, 225 mu g F/ml, 100 mu g F/ml, 100 mu g F/ml and TMP (0.2, 0.4 and 0.6%) solutions (30 s) and storage in artificial saliva, over a duration of 5 days. TMP groups showed lower enamel wear than fluoride-only and placebo groups (p < 0.05). Addition of TMP at a TMP:NaF molar proportion between 1.24:1 and 3.72:1 to a solution containing 100 mu g F/ml presented a greater protective effect under erosive conditions than a solution containing 225 mu g F/ml, in the absence of TMP. Copyright (C) 2011 S. Karger AG, Basel

An improved mouth-piece to prevent environmental contamination during radioaerosol inhalation procedures

The literature suggests that environmental contamination is common during labeled aerosol inhalation procedures in nuclear medicine. We have tested an adherent mask to prevent environmental contamination in 70 procedures. Two groups of patients were evaluated, Group 1 (60 inhalation cases in which the mask was used) presented no environmental contamination in 95% of the procedures (means of 553 dpm and 596 dpm before and after inhalation, p > 0.05, mean of the differences before/after inhalation 6.95, SD = 21.2 dpm) and the only 3 cases in which contamination did occur concerned bearded men; Group 2 (10 inhalation cases in which the mask was not used) showed large increases of environmental radioactive levels in 70% of the procedures (means of 601 dpm and 2,756 dpm before and after inhalation, p < 0.05, mean of the differences 3,066, SD = 2,98 dpm), We conclude that such a mask is very helpful in avoiding environmental contamination during radioaerosol inhalation procedures.

Extensive antigenic and genetic variation among foot-and-mouth disease type A viruses isolated from the 1994 and 1995 foci in São Paulo, Brazil

Nine foot-and-mouth disease virus (FMDV) type A isolates recovered from the field FMD foci in São Paulo State, Brazil, during 1994 and 1995 (a period preceding the last reported focus of FMD in 1996 in this state) were compared among themselves and with the reference vaccine strain A(24)Cruzeiro. The techniques used were sandwich ELISA, virus neutralization (VN), polyacrylamide gel electrophoresis (PAGE) of the structural polypeptides and direct sequencing of the VP1-coding region (1D gene). Results of VN were recorded as serological relationships R and those from ELISA were expressed as percentage of the homologous reaction r. ELISA and VN gave comparable results (correlation coefficient, 0.936) allowing assignment of these field viruses to four groups which were distinct from the A(24)Cruzeiro strain. PAGE and ID nucleotide sequencing were also able to distinguish between these viruses. The high level:of genetic and antigenic variation found when comparing the A(24)Cruzeiro vaccine strain and type A strains recovered, from the last identified foci of FMD came from a formerly endemic area where vaccination with polyvalent vaccines (O(1)Campos, A(24)Cruzciro and C(3)Indaial) had been extensively applied. The similarity between the results of the serological and genetic analyses suggest that the antigenic differences found are mainly located in the 1D protein. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Survey for Foot-and-mouth Disease in the Endangered Marsh Deer (Blastocerus dichotomus) from Marshlands of the Parana River Basin, Brazil

Habitat fragmentation and diseases have resulted in a decline of the marsh deer (Blastocerus (dichotomus) throughout its South American range. Our objectives were to determine whether marsh deer intended for translocation from a region of the Rio Parana Basin had been infected previously by foot-and-mouth disease virus (FMDV) and whether they were carrying virus We captured marsh deer from June to October 1998 and collected blood from 108 animals and esophageal-pharyngeal fluid from 53 Serum was tested for antibodies against three FMDV serotypes (O, A, and C) by liquid-phase-blocking sandwich enzyme-linked immunosorbent assay (ELISA) Esophageal-pharyngeal fluid was tested for FMDV RNA by reverse transcription polymerase chain reaction (RT-PCR) and inoculation into three successive baby hamster kidney (BHK-21) cell subcultures, followed by RT-PCR of cultures We detected low log(10) titers (range 1 0-1 5) to FM DV subtype A(24) Cruzeiro in 19 of 108 sampled marsh deer, but failed to isolate FMDV or detect FMDV RNA in any samples we conclude that marsh deer from our study site were unlikely to carry FMDV, however, as a preventive measure, the 19 animals with titers for FMDV were not sent to FMDV-free Brazilian states

Changes in abiotic characteristics of water in the Paranapanema River and three lateral lagoons at mouth zone of the Jurumirim Reservoir during the flood period, São Paulo, Brazil

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

Plankton richness and abundance in several different hydrological situations in lakes lateral to a river: a case study in the mouth zone of a tributary into a tropical reservoir.

A descriptive analysis of the responses of plankton from lakes lateral to a river in its mouth zone into a tropical reservoir to water level variations is presented. Three situations were reported: 1) a comparison of species richness and diversity and of algae population abundance in prolonged drought and in periods of connection of lakes to the river, 2) the spatial distribution of abundance and richness of Rotifera species in four isolated water bodies formed by fragmentation of a lateral lake during a period of prolonged drought and in the same areas during a period of integrity as an ecosystem, 3) the variability of total zooplankton and Cladocera densities at the end of the isolation period of a lateral lake and after the recovery of connection with the river and in a year of continuous connection with the lotic ecosystem. Various idiosyncrasies were observed in connected lateral lakes, like the surface hydrologic connectivity, a primary factor in species richness modifcations and a secondary controlling factor of plankton abundance. Underground hydrologic connectivity, through the river[forward arrow] lake water fux during the high-water period and lake [forward arrow] river during drought period, appears to have an important role in richness and abundance variations of planktonic populations in the lake isolated from the river.

Regulation of breathing and body temperature of a burrowing rodent during hypoxic-hypercapnia

Burrowing mammals usually have low respiratory sensitivity to hypoxia and hypercapnia. However, the interaction between ventilation (V), metabolism and body temperature (Tb) during hypoxic-hypercapnia has never been addressed. We tested the hypothesis that Clyomys bishopi, a burrowing rodent of the Brazilian cerrado, shows a small ventilatory response to hypoxic-hypercapnia, accompanied by a marked drop in Tb and metabolism. V, Tb and O-2 consumption (VO2) of C. bishopi were measured during exposure to air, hypoxia (10% and 7% O-2), hypercapnia (3% and 5% CO2) and hypoxic-hypercapnia (10% O-2 + 3% CO2). Hypoxia of 7% but not 10%, caused a significant increase in V, and a significant drop in Tb. Both hypoxic levels decreased VO2 and 7% O-2 significantly increased V/VO2. Hypercapnia of 5%, but not 3%, elicited a significant increase in V, although no significant change in Tb, VO2 or V/VO2 was detected. A combination of 10% O-2 and 3% CO2 had minor effects on V and Tb, while VO2 decreased and V/VO2 tended to increase. We conclude that C. bishopi has a low sensitivity not only to hypoxia and hypercapnia, but also to hypoxic-hypercapnia, manifested by a biphasic ventilatory response, a drop in metabolism and a tendency to increase V/VO2. The effect of hypoxic-hypercapnia was the summation of the hypoxia and hypercapnia effects, with respiratory responses tending to have hypercapnic patterns while metabolic responses, hypoxic patterns. (C) 2004 Elsevier B.V. All rights reserved.

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.

Effects of temperature and hypercapnia on ventilation and breathing pattern in the lizard Uromastyx aegyptius microlepis

In most reptiles, the ventilatory response to hypercapnia consists of large increases in tidal volume (V-T), whereas the effects on breathing frequency (f(R)) are more variable. The increased V-T seems to arise from direct inhibition of pulmonary stretch receptors. Most reptiles also exhibit a transitory increase in ventilation upon removal of CO2 and this post-hypercapnic hyperpnea may consist of changes in both V-T and f(R). While it is well established that increased body temperature augments the ventilatory response to hypercapnia, the effects of temperature on the post-hypercapnic hyperpnea is less described. In the present study, we characterise the ventilatory response of the agamid lizard Uromastyx aegyptius to hypercapnia and upon the return to air at 25 and 35 degreesC. At both temperatures, hypercapnia caused large increases in V-T and small reductions in f(R), that were most pronounced at the higher temperature. The post-hypercapnic hyperpnea, which mainly consisted of increased fR, was numerically larger at 35 compared to 25 degreesC. However, when expressed as a proportion of the levels of ventilation reached during steady-state hypercapnia, the post-hypercapnic hyperpnea was largest at 25 degreesC. Some individuals exhibited buccal pumping where each expiratory thoracic breath was followed by numerous small forced inhalations caused by contractions of the buccal cavity. This breathing pattern was most pronounced during severe hypercapnia and particularly evident during the post-hypercapnic hyperpnea. (C) 2002 Published by Elsevier B.V.

Role of the post-hepatic septum on breathing during locomotion in Tupinambis merianae (Reptilia : Teiidae)

Tupinambis merianae increased minute ventilation by increasing both tidal volume and breathing frequency during sustained locomotion at 0.17 m s(-1). Animals in which the post-hepatic septum (PHS) had been surgically removed were not able to increase tidal volume during locomotion. Tegus without PHS compensated, in part, by increasing breathing frequency above the levels observed for tegus with intact PHS, but minute ventilation remained less than in the control animals. The rate of oxygen consumption and the air convection requirement, however, were not significantly different between animals with and without PHS, nor at the tested speeds was endurance affected by the removal of the PHS. These data suggest that the PHS facilitates ventilation by acting as a mechanical barrier, preventing the viscera from moving cranially during physical exertion.

Cardiorespiratory responses to hypoxia in the African catfish, Clarias gariepinus (Burchell 1822), an air-breathing fish

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

The contribution of air breathing to aerobic scope and exercise performance in the banded knifefish Gymnotus carapo L.

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

Locus coeruleus noradrenergic neurons and CO2 drive to breathing

The Locus coeruleus (LC) has been suggested as a CO2 chemoreceptor site in mammals. In the present study, we assessed the role of LC noradrenergic neurons in the cardiorespiratory and thermal responses to hypercapnia. To selectively destroy LC noradrenergic neurons, we administered 6-hydroxydopamine (6-OHDA) bilaterally into the LC of male Wistar rats. Control animals had vehicle (ascorbic acid) injected (sham group) into the LC. Pulmonary ventilation (plethysmograph), mean arterial pressure (MAP), heart rate (HR), and body core temperature (T-c, data loggers) were measured followed by 60 min of hypercapnic exposure (7% CO2 in air). To verify the correct placement and effectiveness of the chemical lesions, tyrosine hydroxylase immunoreactivity was performed. Hypercapnia caused an increase in pulmonary ventilation in all groups, which resulted from increases in respiratory frequency and tidal volume (V-T) in sham-operated and 6-OHDA-lesioned groups. The hypercapnic ventilatory response was significantly decreased in 6-OHDA-lesioned rats compared with sham group. This difference was due to a decreased V-T in 6-OHDA rats. LC chemical lesion or hypercapnia did not affect MAP, HR, and T-c. Thus, we conclude that LC noradrenergic neurons modulate hypercapnic ventilatory response but play no role in cardiovascular and thermal regulation under resting conditions.