Embryotoxicity and Fertility Study with Halothane Subanesthetic Concentration in Rats

The effect of 9 ppm halothane, a subanesthetic concentration, was studied on the reproductive ability and pregnancy outcome in white rats. Pregnant females were exposed for 4 h per day during the whole gestation period. Male animals were subjected to halothane inhalation for 4 h daily, 5 days per week for 6 or 8 months. In the exposed females higher rates were established for early interruption of pregnancy (all implants dead) and for embryonic death in the later periods of intrauterine life compared to controls. Deciduomata were found in 22.22% ( P <0.05) of pregnant treated females. Control females mated to exposed males showed a higher incidence of preimplantation loss (36.36% ( P<0.05 ) of those mated with males exposed for 6 months had deciduomata). Decreased fertility in males, expressed particularly in the 8-month treated group, was also demonstrated (13.33% inseminated females, compared to 35% in the control group).     

Traditional bowel preparation versus osmotic agent mannitol for preoperative colonic cleansing in elective colorectal surgery

BACKGROUND: The need for mechanical cleansing of the bowel before elective colorectal surgery is generally accepted. There are various methods for preparation in use today, but it is still controversial which of them is superior to the others. AIM: To determine whether there is a significant difference in postoperative infectious wound complications rate between the traditional bowel preparation and oral lavage with the osmotic agent Mannitol. METHODS: A retrospective study from January 1997 to June 2000 was performed. Patients who underwent elective surgery for colorectal carcinomas were divided into two groups according to the method of colonic cleansing that was used. The traditional bowel preparation was performed with 30.0 cc Castor oil given per os in the day before the operation and three soap enemas (Group I). Patients from the other group (Group II) were given 500 cc 10% Mannitol in the day before the operation. RESULTS: There were 154 patients in Group I and 36 patients in Group II. Infectious wound complications developed in 26 patients from Group I versus 13 patients from Group II. The difference was statistically significant (16.9% vs. 36.1%, p < 0.01). The differences in the incidence of anastomotic leaks and mortality rate between the two groups were without statistical significance. CONCLUSION: The use of Mannitol is associated with increase in the postoperative infectious wound complications and therefore should be avoided as colonic cleansing method in elective colorectal surgery.     

Surgical treatment of chronic mandibular dislocation--report of a case

Chronic dislocation of the temporomandibular jaw (TMJ) can result from lax joint ligaments and parafunctioning joints; it can also be a consequence of a systemic connective tissue disorder. The authors report a case of hypermobile joint syndrome in combination with mitral valve prolapse. The case was managed by osteosynthesis using modified titanium plate.     

Nasal and sleep cycle--possible synchronization during night sleep

Regular cyclic changes in nostril airflow due to a nasal congestion and decongestion are known in literature as nasal cycle. Registration of breathing from each nostril separately gives possibility to registrate moments of alternative change of airflow of nostrils and periods of nasal cycle. This registration during night sleep shows that the length of these periods are about 1.5h, 3.0 h and 4.5h. The length of these periods are multiple of mean length of sleep cycle--about 1.5h. The alternative change of airflow through nostrils occurs through some of REM stages of the sleep. This shows, that during the night sleep becomes synchronization of nasal and sleep cycles in some of the REM phases of sleep. As a result--length of periods of the nasal cycle are one or more length of sleep cycle.     

Simultaneous application of intravenous fat emulsion and charcoal hemoperfusion in quetiapine overdose case

The simultaneous application of intravenous fat emulsion and charcoal hemoperfusion in the case of severe quetiapine poisoning is described. The initial blood concentration of quetiapine was 5.9 µg/mL and rapid deterioration in the patient status was observed. When a lipid emulsion was infused a fast blood pressure recovery occurred which allows to perform extracorporeal clearance using charcoal hemoperfusion. At the end of the procedure the quetiapine concentration was decreased down to 1.5 µg//mL and fast recovery of the patient was observed.     

Characterization of Train-Induced Vibration and its Effect on Fecal Corticosterone Metabolites in Mice

Excessive environmental vibrations can have deleterious effects on animal health and experimental results, but they remain poorly understood in the animal laboratory setting. The aims of this study were to characterize train-associated vibration in a rodent vivarium and to assess the effects of this vibration on the reproductive success and fecal corticosterone metabolite levels of mice. An instrumented cage, featuring a high-sensitivity microphone and accelerometer, was used to characterize the vibrations and sound in a vivarium that is near an active railroad. The vibrations caused by the passing trains are 3 times larger in amplitude than are the ambient facility vibrations, whereas most of the associated sound was below the audible range for mice. Mice housed in the room closest to the railroad tracks had pregnancy rates that were 50% to 60% lower than those of mice of the same strains but bred in other parts of the facility. To verify the effect of the train vibrations, we used a custom-built electromagnetic shaker to simulate the train-induced vibrations in a controlled environment. Fecal pellets were collected from male and female mice that were exposed to the simulated vibrations and from unexposed control animals. Analysis of the fecal samples revealed that vibrations similar to those produced by a passing train can increase the levels of fecal corticosterone metabolites in female mice. These increases warrant attention to the effects of vibration on mice and, consequently, on reproduction and experimental outcomes.Abbreviations: FCM, fecal corticosterone metabolites; LPSC, Linus Pauling Science CenterTo reduce confounding variables, many laboratory conditions are standardized (light cycle duration, air quality, temperature, and relative humidity) to a narrowly defined acceptable range.¹⁰ Environmental sound and vibration in animal vivaria are two potentially overlooked factors that could have detrimental impacts on the ability of researchers to produce consistent experimental results. The Guide for the Care and Use of Laboratory Animals suggests that activities that produce sound and vibration in animal rooms should be minimized, citing the potential for animal distress and altered research results.¹⁰ The effect of sound on the physiology and behavior of mice is widely recognized and can range from mild distress to reduced reproductive efficiency and audiogenic seizures in some strains of mice.^25,36 The hearing range of mice is speculated to range from 1 to 100 kHz in contrast to human hearing, which is between 20 Hz and 20 kHz.^7,13 It is important to note, however, that the hearing range of mice is a subject of debate because of an inability to accurately determine the true lower and upper bounds of mouse hearing.¹³ Some researchers indicate that the lower frequency limit for the hearing of mice is at 2.3 kHz, whereas others state that the greatest hearing sensitivity in mice occurs between 12 to 24 kHz.^7,37 The disparity between the hearing range of mice and that of humans has led to the speculation that humans may overestimate how loud or bothersome certain sounds are to laboratory mice.²⁶Whereas the hearing ranges of laboratory mice have been quantified,^7,13,37 there are no published data on a specific perception threshold for vibration in mice. However, information pertaining to the pathologic or physiologic effects seen with whole-body vibration at several amplitudes and frequencies has been reported.^{3–5,16,27,34,35} In rats, whole-body vibration increased plasma corticosterone and brain serotonin levels at 0.4 × g and 20 Hz.¹ Increased adrenal weight and decreased gastric emptying time were observed at 2.0 to 2.4 × g and 5 to 15 Hz.^28,30 In mice, whole-body vibration decreased adipogenesis,²⁷ and increased bone formation at 0.1 to 0.3 m/s² and up to 90 Hz,^27,34,35 suggesting that vibration at those levels is biologically significant. In terms of reproduction as well as deformities, vibration has been reported to increase rates of fetal resorption and cleft palate and has been linked to cannablism.^14,16Vibration in the form of ‘shaker stress’ has been reported as a stress model, in which customized cages are mounted on a shaking platform with a 2- to 3-cm stroke at 60 to 150 cycles per minute.^3,4,18 Shaker stress is a pain-free stimulus that has been shown to cause reproducible changes in blood pressure, heart rate, sympathetic activity, and stress hormone secretion.^6,18Despite the well-documented evidence of stress induction due to whole-body vibration in rodents, little information exists regarding the effects of environmental vibration on laboratory mice in standard housing conditions. One study²⁰ investigated the vibrations produced by various heavy machinery during building construction and compared them with the resonant frequencies of three anatomic locations in several species, including mice, rats, and humans. The authors concluded that particular vibration frequency ranges are more likely to affect rats and mice as compared with humans.²⁰ More research is needed to encompass the various vibration scenarios that occur in the laboratory setting—only then can standards be formulated to control and mitigate this biologic stressor.Laboratory animal vivaria are constructed to suit the needs of the institution in regard to proximity to other research facilities, campus land-use planning, and land restrictions. As a result, laboratory animal housing can be located near subways, trains, or highways, all of which might transmit vibrations at magnitudes and frequencies that cause stress in rodents. As a case in point, the Laboratory Animal Resources Center at Oregon State University is located approximately 30 m from an active railroad track. On average, 4 trains of various lengths pass the building each afternoon.The closest animal room to the train tracks developed problems with abnormally high rates of cannibalism or neglect of pups. After investigating other potential causes such as temperature variations, light–dark cycles, and diet, we hypothesized that the vibrations from the train were a significant factor. The reproductive success of the same set of mice improved after they were moved from a flat wire rack to a single motor-ventilated rack. The ventilated racks hold cages in place with a cage clip and therefore might decrease cage-to-rack vibration. In addition, ventilated racks are much heavier than are wire racks and have an air intake and exhaust system that generates its own constant minor background vibrations; these factors may contribute to a dampening or partial masking of the potentially more startling short-duration, intense train-induced vibrations. Similar high rates of preweaning mortality have not occurred at the other main rodent housing facility on campus, the Linus Pauling Science Center (LPSC), which is a state-of-the-art science facility that was constructed in 2011 and lies approximately 490 m away from the railroad tracks. The differences in mouse reproductive success between the facilities and rack types prompted us to investigate the effects of environmental vibration.Vibrations and sound are disturbances that travel through a medium. Vibrations often move through a solid medium, whereas sound passes through a gaseous or liquid one, such as air or water. The disturbances caused by vibrations and sound can often be represented by a wave model. Waves oscillate with a specific frequency and have particular amplitudes, which change as the waves propagate from the source. For this study, it is important to know the frequency and amplitude of the waves that are measured to categorize their effects. Certain wave frequencies and amplitudes may be more detrimental to the health of the mice. The majority of the energy produced by trains moving on the ground surface is conveyed by Rayleigh waves.^23,29 Such vibration waves usually have a frequency between 2 to 80 Hz, frequencies that can disturb people.^23,29 Regarding sound, the energy generated at the source travels through the air as a longitudinal or pressure wave.²⁴ The ears of humans and mice are designed to process a broad frequency range, and a decibel scale is used to indicate sound pressure in a concise manner.The specific goal of the current study was to characterize the effects of train-associated vibration and sound on laboratory mice housed on flat racks. During the preliminary observational part of the study, the vibrations from trains were characterized in terms of magnitude and frequency. In addition, the reproductive success of mice housed in a vibration-prone room in the vivarium was monitored. To further explore the effects of train-induced vibration more objectively, the second part of the study exposed a set of mice to environmental vibration in a controlled setting. To create controlled vibrations, an electromagnetic shaker was designed and constructed to induce vibrations similar to those produced by the trains passing the vivarium. The mice were monitored by measuring fecal corticosterone metabolites (FCM). We hypothesized that mice exposed to train vibrations have elevated FCM.