The low fertility of repeat-breeder cows during summer heat stress is related to a low oocyte competence to develop into blastocysts

It was hypothesized the lower fertility of repeat-breeder (RB) Holstein cows is associated with oocyte quality and this negative effect is enhanced during summer heat stress (HS). During the summer and the winter, heifers (H; n = 36 and 34, respectively), peak-lactation (PL; n = 37 and 32, respectively), and RB (n = 36 and 31, respectively) Holstein cows were subjected to ovum retrieval to assess oocyte recovery, in vitro embryonic developmental rates, and blastocyst quality [terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and total cell number]. The environmental temperature and humidity, respiration rate, and cutaneous and rectal temperatures were recorded in both seasons. The summer HS increased the respiration rate and the rectal temperature of PL and RB cows, and increased the cutaneous temperature and lowered the in vitro embryo production of Holstein cows and heifers. Although cleavage rate was similar among groups [H = 51.7% +/- 4.5 (n = 375), PL = 37.9% +/- 5.1 (n = 390), RB = 41.9% +/- 4.5 (n = 666)], blastocyst rate was compromised by HS, especially in RB cows [H = 30.3% +/- 4.8 (n = 244) vs. 23.3% +/- 6.4 (n = 150), PL = 22.0% +/- 4.7 (n = 191) vs. 14.6% +/- 7.6 (n = 103), RB = 22.5% +/- 5.4 (n = 413) vs. 7.9% +/- 4.3 (n = 177)]. Moreover, the fragmentation rate of RB blastocysts was enhanced during the summer, compared with winter [4.9% +/- 0.7 (n = 14) vs. 2.2% +/- 0.2 (n = 78)] and other groups [H = 2.5% +/- 0.7 (n = 13), and PL = 2.7% +/- 0.6 (n = 14)] suggesting that the association of RB fertility problems and summer HS may potentially impair oocyte quality. Our findings provide evidence of a greater sensitivity of RB oocytes to summer HS.

Cell cycle and apoptosis in normal and cloned bovine near-term placentae

The bovine maternal epithelium is composed of cuboidal cells interspersed with low columnar cells having centrally located nuclei. Bovine trophoblast is composed of two cell types: mononuclear trophoblastic and giant trophoblastic cells that can have two or more nuclei. Number of apoptotic cells and proliferative cells are variable in both cell populations. This study compared tissue growth and apoptosis by flow cytometry in the cell population found at distinct placental regions (central region of placentomes, <= 1-cm microplacentomes and the interplacentomal region) between normal and cloned near-term bovine pregnancies. After a morphological comparison between regions and groups (controls vs. clones), a lesser proportion of diploid to tetraploid cells was observed in the central region of placentomes and in microplacentomes from cloned-derived pregnancies. In addition, cloned animals had a fewer apoptotic cells in the central region of the placentome and in interplacentomal region and a greater proliferative capacity in all regions (cells in G(2)/M) near term as opposed to control animals. These results may reveal the existence of a relationship between such changes in the proportions of uterine and trophoblastic epithelial cells at the end of pregnancy and normal placental function. This could be related to faulty placentation in early pregnancy, placental insufficiency during pregnancy or lack of placental and/or fetal maturation in late pregnancy, which may contribute to someof the abnormalities after in vitro embryo manipulations, such as poor preparation and initiation of parturition, prolonged gestation and lesser post-natal survival in some cloned animals. (C) 2008 Elsevier B.V. All rights reserved.

Peripartum Haemodynamic Status of Bitches with Normal Birth or Dystocia

There has been limited investigation of parturition in the bitch and there is little information published on clinical and obstetrical examination other than opinion and anecdote. While there are substantial data on haemodynamic and vascular changes during normal parturition in humans, little is known about the physiological events in the dog. This study was aimed at maternal haemodynamic changes occurring during normal parturition and to investigate how these were modified in bitches with dystocia (DYST) treated either medically or via assisted delivery and caesarean operation. Three groups of 10 bitches were investigated; those with normal parturition, those with DYST corrected by manipulative assistance or caesarean operation and those with uterine inertia treated by oxytocin administration. Heart rate, systolic and diastolic blood pressure, electrocardiogram and blood glucose concentration were measured pre-partum, intra-partum, immediately after parturition and 1 h later. Heart rate was high at all times throughout the study and the majority of bitches had normal sinus rhythm. Blood pressure was generally within the normal range, and although systolic and diastolic blood pressure was highest during the intra-partum period and sometimes during the immediate post-partum period, there were no significant differences between groups. All bitches had blood glucose concentrations within the normal range throughout the study although pre-partum concentrations were statistically lower than many of the other time periods. The study provides useful physiological data that will facilitate monitoring and clinical management of bitches throughout normal parturition and DYST.

Neonatal Clinical Evaluation, Blood Gas and Radiographic Assessment After Normal Birth, Vaginal Dystocia or Caesarean Section in Dogs

This study aimed to standardize signs and diagnostic criteria of respiratory function in newborn puppies delivered normally or after dystocia and caesarean operation. A total of 48 neonates were allocated into groups: eutocia (n = 20), dystocia (n = 8), caesarean (c)-section (n = 20). Neonatal health was assessed using the Apgar score and body temperature was determined at 0, 5 and 60 min after delivery. Venous blood gases (pO(2) and SO(2)) was measured immediately and 60 min after delivery, and a thoracic radiograph was made between 0 and 5 min of life. The c-section group had significantly lower Apgar scores at birth and 5 min. Hypothermia was present at 5 min in the eutocia and c-section groups, and at 60 min in all groups. The eutocia group had an irregular respiratory pattern in 78% of puppies at birth, 27.7% at 5 min and 21% at 60 min compared with 87.5%, 62.5% and 12.5% of the pups in the dystocia group where there was irregular respiratory rhythm, moderate to intense respiratory sounds with agonic episodes. The c-section group had respiratory alterations in 70%, 45% and 16% of puppies at 0, 5 and 60 min, respectively. Radiographic abnormalities were present in 17% of the pups in the eutocia group, 25% of the pups in the dystocia group and 30% of the pups in the c-section group, respectively. The c-section group had significantly lower SO(2) values at 60 min than at birth. All puppies had hypoxaemia, but a significant decrease was observed in the c-section group. Newborn puppies had tissue hypoxia and irregular respiratory pattern at birth. Caesarean-section puppies had lower vitality; however, all developed satisfactory Apgar scores at 5 min of life, regardless of the obstetric condition.

Acid-Base Changes in Canine Neonates Following Normal Birth or Dystocia

There are limited data concerning blood gas parameters in neonatal dogs. Knowledge of the normal physiology may facilitate effective therapeutic intervention and potentially reduce neonatal mortality. This study examined acid-base parameters in pups born at normal parturition (n = 27) compared with those born after obstetrical assistance or caesarean operation (n = 13) and those born following oxytocin (OXY) administration for treatment of uterine inertia (n = 11). Pups were subjected to an objective scoring method of neonatal health adapted from use in humans (the Apgar score) at birth and again at 5 and 60 min after birth. Venous blood samples were collected at 5 and 60 min after birth for evaluation of blood gas parameters. At birth, all pups had low Apgar scores and a mixed acidosis. The base excess was lowest for pups delivered after OXY administration. The Apgar score improved for all pups after 5 min of birth and there was an improvement in carbon dioxide tension, base excess and venous blood pH at 1 h, although in all pups a metabolic acidosis persisted. These data provide an important insight into neonatal physiology and the variability of blood gas parameters in pups born at normal and abnormal parturition and provide the basis for clinical decision making following dystocia.

Hepatic function evolution in dogs anesthetized with Zolazepam/Tiletamine

The hepatic effects of the anesthetic association zolazepam/tiletamine were investigated in dogs by analyzing the serum concentration of hepatic enzymes. Ten healthy dogs were divided into two groups of five, group I (GI) and group II (GII). The animals of GI received a single dose of 6,6 mg/kg of zolazepam/tiletamine, by intramuscular (IM) injection. GII dogs received 6,6 mg/kg of zolazepam/tiletamine by the IM route; after a period of 50 - 80 minutes the animals received two additional doses (3,3 mg/kg) by intravenous administration[SAH1]. The hepatic function were analyzed by monitoring the serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl-transferase (GGT). Four blood samples were collected in different moments during the analyses: M0, before the first application of the drug; and M1 to M4. M1 through M3 was collected with intervals of 20 minutes before M0, while M4 was obtained 24 hours after M1. The normality of the obtained results was analyzed by Kolmogorov-Smirnov Test; while the Tukey`s test compared the means, using a level of significance of 5% for both statistical analyses. The mean values of all enzymes evaluated were within normal limits for both experimental groups, without any significant statistical alteration being observed between and within these groups. These results demonstrated that the association of zolazepam/tiletamine at the dosage of 6.6 mg/kg, followed by two applications additional of 3.3 mg/kg resulted in elevation of the evaluated hepatic enzymes without exceeding the physiologic values. Additionally, a single application of 6.6 mg/kg of zolazepam/tiletamine by the intramuscular route resulted in lower values when compared to three applications.

Differences in thermoregulatory ability between slick-haired and wild-type lactating Holstein cows in response to acute heat stress

Animals inheriting the slick hair gene have a short, sleek, and sometimes glossy coat. The objective of the present study was to determine whether slick-haired Holstein cows regulate body temperature more effectively than wild-type Holstein cows when exposed to an acute increase in heat stress. Lactating slick cows (n = 10) and wild-type cows (n = 10) were placed for 10 h in an indoor environment with a solid roof, fans, and evaporative cooling or in an outdoor environment with shade cloth and no fans or evaporative cooling. Cows were exposed to both environments in a single reversal design. Vaginal temperature, respiration rate, surface temperature, and sweating rate were measured at 1200, 1500, 1800, and 2100 h (replicate 1) or 1200 and 1500 h (replicate 2), and blood samples were collected for plasma cortisol concentration. Cows in the outdoor environment had higher vaginal and surface temperatures, respiration rates, and sweating rates than cows in the indoor environment. In both environments, slick-haired cows had lower vaginal temperatures (indoor: 39.0 vs. 39.4 degrees C; outdoor 39.6 vs. 40.2 degrees C; SEM = 0.07) and respiration rate (indoor: 67 vs. 79 breaths/min; outdoor 97 vs. 107 breaths/min; SEM = 5.5) than wild-type cows and greater sweating rates in unclipped areas of skin (indoor: 57 vs. 43 g.h(-1)/m(2); outdoor 82 vs. 61 g.h(-1)/m(2); SEM = 8). Clipping the hair at the site of sweating measurement eliminated the difference between slick-haired and wild-type cows. Results indicate that slick-haired Holstein cows can regulate body temperature more effectively than wild-type cows during heat stress. One reason slick-haired animals are better able to regulate body temperature is increased sweating rate.

Heat Release, Time Required, and Cleaning Ability of Mtwo R and ProTaper Universal Retreatment Systems in the Removal of Filling Material

Introduction: This ex vivo study evaluated the heat release, time required, and cleaning efficacy of MTwo (VDW, Munich, Germany) and ProTaper Universal Retreatment systems (Dentsply/Maillefer, Ballaigues, Switzerland) and hand instrumentation in the removal of filling material. Methods: Sixty single-rooted human teeth with a single straight canal were obturated with gutta-percha and zinc oxide and eugenol-based cement and randomly allocated to 3 groups (n = 20). After 30-day storage at 37 degrees C and 100% humidity, the root fillings were removed using ProTaper UR, MTwo R, or hand files. Heat release, time required, and cleaning efficacy data were analyzed statistically (analysis of variance and the Tukey test, alpha = 0.05). Results: None of the techniques removed the root fillings completely. Filling material removal with ProTaper UR was faster but caused more heat release. Mtwo R produced less heat release than the other techniques but was the least efficient in removing gutta-percha/sealer. Conclusions: ProTaper UR and MTwo R caused the greatest and lowest temperature increase on root surface, respectively; regardless of the type of instrument, more heat was released in the cervical third. Pro Taper UR needed less time to remove fillings than MTwo R. All techniques left filling debris in the root canals. (I Endod 2010;36:1870-1873)

Evaluation of pH and Calcium Ion Release of Root-end Filling Materials Containing Calcium Hydroxide or Mineral Trioxide Aggregate

Introduction: To evaluate calcium ion release and pH of Sealer 26 (S26) (Dentsply, Rio de Janeiro, RJ, Brazil), white mineral trioxide aggregate (MTA), Endo CPM Sealer (CPM1) (EGEO SRL Bajo licencia MTM Argentina SA, Buenos Aires, Argentina), Endo CPM Sealer in a thicker consistency (CPM 2), and zinc oxide and eugenol cement (ZOE). Methods: Material samples (n = 10) were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 3, 6,12,24, and 48 hours and 7,14, and 28 days, the water pH was determined with a pH meter, and calcium release was assessed by atomic absorption spectrophotometry. An empty tube was used as the control group. Results: The control group presented a pH value of 6.9 at all studied periods and did not show the presence of calcium ion. S26 presented greater hydroxyl ion release up to 12 hours (p < 0.05). From 24 hours until 28 days, S26, MTA, CPM1, and CPM2 had similar results. in ail periods, ZOE presented the lowest hydroxyl ion release. CPM1, followed by CPM2, released the most calcium ions until 24 hours (p < 0.05). Between 48 hours and 7 days, CPM1 and CPM2 had the highest release. A greater calcium ion release was observed for CPM2, followed by CPM1 at 14 days and for S26, CPM1, and CPM2 at 28 days. ZOE released the least calcium ions in all periods. Conclusion: Sealer 26, MTA, and Endo CPM sealer at normal or thicker consistency release hydroxyl and calcium ions. Endo CPM sealer may be an alternative as root-end filling material. (J Endod 2009;35:1418-1421)

Tooth-wear patterns in adolescents with normal occlusion and Class II Division 2 malocclusion

Introduction: In this study, we investigated tooth-wear patterns in adolescents with either normal occlusion or Class II Division 2 malocclusion. Methods: The sample consisted of dental casts from 165 subjects that were divided into 2 groups: 115 normal occlusion subjects (mean age, 14.3 years) and 50 complete Class II Division 2 subjects (mean age, 13.9 years). Dental wear was assessed by using a modified version of the tooth wear index. The 2 groups were compared with the Mann-Whitney test for the frequency and severity of wear on each surface of each group of teeth. The level of statistical significance was set at 5%. Results: The normal occlusion group statistically had greater tooth wear on the incisal surfaces of the maxillary lateral incisors and the incisal surfaces of the maxillary canines than did the Class II Division 2 malocclusion group. The malocclusion group showed statistically greater tooth wear on the labial surfaces of the mandibular lateral incisors, the occlusal surfaces of the maxillary premolars and first molars, the occlusal surfaces of the mandibular premolars, the palatal surfaces of the maxillary second premolars, and the buccal surfaces of the mandibular premolars and first molars than did the normal occlusion group. Conclusions: Subjects with normal occlusion and those with complete Class II Division 2 malocclusions have different tooth-wear patterns. Tooth wear on the malocclusion subjects should not be considered pathologic but, rather, the consequence of different interocclusal arrangements. (Am J Orthod Dentofacial Orthop 2010;137:730.e1-730.e5)

Tooth-wear patterns in subjects with Class II Division 1 malocclusion and normal occlusion

Introduction: The aim of this study was to investigate the prevalence of tooth wear in adolescents with Class II malocclusion, compared with those with normal occlusion. Methods: The sample consisted of dental casts obtained from 310 subjects, divided into 3 groups: group 1, 110 subjects with normal occlusion (mean age, 13.51 years); group 2, 100 complete Class II Division 1 patients (mean age, 13.44 years); and group 3, 100 half-cusp Class II Division 1 patients (mean age, 13.17 years). Dental wear was assessed by using a modified version of the tooth-wear index. The 3 groups were compared by means of the Kruskal-Wallis and Dunn tests, considering the frequency and the severity of wear on each surface of each group of teeth. The level of statistical significance was set at 5%. Results: The normal occlusion group had statistically greater tooth wear on the palatal surfaces of the maxillary central incisors and the incisal surfaces of the maxillary canines than the corresponding surfaces in both Class II malocclusion groups. The complete and half-cusp Class II Division 1 malocclusion groups had statistically greater tooth wear on the occlusal surfaces of the maxillary second premolar and first molar, the occlusal surfaces of the mandibular premolars, and the buccal surfaces of the mandibular posterior teeth compared with the normal occlusion group. The half-cusp Class II Division 1 malocclusion group had significantly greater tooth wear on the incisal surfaces of the mandibular incisors compared with the complete Class II Division 1 malocclusion group. Conclusions: Subjects with normal occlusion and complete or half-cusp Class II Division 1 malocclusions have different tooth-wear patterns. Tooth wear on the malocclusion subjects should not be considered pathologic but rather consequent to the different interocclusal tooth arrangement. (Am J Orthod Dentofacial Orthop 2010; 137: 14. e1-14.e7)

Speech intelligibility with and without noise in individuals exposed to electronic music

Audiometry is the main way with which hearing is evaluated, because it is a universal and standardized test. Speech tests are difficult to standardize due to the variables involved, their performance in the presence of competitive noise is of great importance. Aim: To characterize speech intelligibility in silence and in competitive noise from individuals exposed to electronically amplified music. Material and Method: It was performed with 20 university students who presented normal hearing thresholds. The speech recognition rate (SRR) was performed after fourteen hours of sound rest after the exposure to electronically amplified music and once again after sound rest, being studied in three stages: without competitive noise, in the presence of Babble-type competitive noise, in monotic listening, in signal/ noise ratio of + 5 dB and with the signal/ noise ratio of 5 dB. Results: There was greater damage in the SRR after exposure to the music and with competitive noise, and as the signal/ noise ratio decreases, the performance of individuals in the test also decreased. Conclusion: The inclusion of competitive noise in the speech tests in the audiological routine is important, because it represents the real disadvantage experienced by individuals in daily listening.

Evaluation of distances between the mandibular teeth and the alveolar process in Brazilians with normal occlusion

Introduction: The aims of this study were to evaluate the distances between the mandibular permanent teeth and the alveolar process in Brazilians with normal occlusion and to compare them with normal American values. Methods: We used 59 mandibular casts from untreated subjects who had permanent dentition and the 6 keys to normal occlusion. A computer program was used to calculate the distances between the dental reference points and the alveolar process for each tooth. The mean values were then compared to the normal values by applying the Student t test at a significance level of 0.05. Results: The results showed a progressive increase of these distances from the anterior region (incisors) to the posterior region (molars), from 0.00 to 2.49 mm. All measurements had statistically significant differences from the American sample, except for the values for canines and first premolars. Conclusions: Brazilians with normal occlusion have more lingual crown positions for the incisors, second premolars, and molars compared with Americans with normal occlusion. Although these findings were statistically significant, they are unlikely to be clinically significant. (Am J Orthod Dentofacial Orthop 2010; 137: 308.e1-308.e4)