Technical note Communication: Frequency of cage changing and weight gain in rats

We have studied the influence of the frequency of cage changing on body weight gain in young female rats over a 2-week period. Rats were subjected to either true or sham cage changing so as to balance for possible effects of handling. Cage changing once every day or once every three days caused significantly lower rates of weight gain in the first but not second week of study than did cage changing once every 14 days. It is suggested tentatively that stress associated with cage changing is responsible for the observed growth inhibiting effect

Usoda skrb vzbujajočih onesnaževal v jezerih, nastalih v vrtačah, Florida, ZDA

Zakrasele karbonatne platforme, kot je Florida, zaznamujejo hitra stopnja infiltracije, visoka prepustnost podlage in neposredna povezava z vodonosniki prek številnih vrtač. Kombinacija teh fizikalnih lastnosti prispeva k visoki občutljivosti podtalnice in vodonosnikov na kontaminacijo s skrb vzbujajočimi sintetičnimi kemikalijami. Uporaba greznic spodbuja vnos teh onesnaževal v okolje. Da bi proučili vpliv kemikalij na kraško pokrajino, so bili vzorci vode, sedimenta in vegetacije odvzeti v jezeru, nastalem v vrtači in obdanem s stanovanji, ki so opremljena z greznicami. Glavno vprašanje tega raziskovalnega projekta je, kaj se dogaja z onesnaževali iz grezničnih odplak v vodnem zajetju vrtače. Za analizo vzorcev je bila izvedena masna spektrometrija s tekočinsko kromatografijo. Ugotovljeno je bilo, da je sorazmerna količina kemikalij odvisna od 1) hidrofobnosti in polarnosti spojine, 2) mesta vzorčenja, 3) topografskega gradienta in 4) za vegetacijo, povezanosti vrste vzorca s sedimentom. Hidrogeološke študije so pokazale, da so vrtače na tem območju povezane z vodonosnikom, ki je pod njimi. Posledično skrb vzbujajoča onesnaževala predstavljajo tveganje za onesnaženje podtalnice. Ta študija je prikaz razmer v sušni sezoni Floride, to je najverjetneje obdobje z najmanjšo kontaminacijo. Vzorčenje bi bilo treba opraviti v tudi deževnem obdobju, ko izpiranje onesnaževal iz greznic lahko poveča koncentracije onesnaževal, tako v jezeru kot v vodonosnikih, kar je posebno problematično zaradi uporabnosti vode iz vodnjaka v prehranske namene. Čeprav je bila študija izvedena na Floridi, verjamemo, da so naše ugotovitve in priporočila splošno uporabni, saj se greznice uporabljajo v številnih kraških predelih sveta.Highly karstified carbonate platforms such as Florida are characterized by rapid infiltration rates, highly permeable bedrock and the direct connection to the below aquifer through the high density of sinkholes. This combination of physical features makes the groundwater and aquifers highly vulnerable to contamination from synthetic chemicals commonly referred to as contaminants of emerging concern (CECs). The use of septic tanks, otherwise referred to as onsite water treatment systems (OWTS), promotes the introduction of CECs into the environment. In order to study the impacts of CECs from OWTS on a karst landscape, water, sediment, and vegetation samples were collected in a sinkhole lake surrounded by residential housing using this waste disposal method. The main question of this research project is what is the fate of CECs from OWTSs effluent within the catchment of a sinkhole lake? Liquid chromatograph mass spectrometry was used to analyze the samples for the presence of CECs. It was found that the relative quantity of CECs in the individual constituents is dependent upon 1) the hydrophobicity and polarity of the individual compound, 2) the specific sampling site, 3) the topography gradient, and 4) for vegetation, the connectedness of the sample type to the sediment. Hydrogeological studies have found that the sinkholes of the area are all connected to the below aquifer. Consequently, these CECs pose a risk of the contamination of the groundwater. This study is a temporal snapshot, that being the dry season of Florida which is most likely the time of lowest CEC contamination. It is imperative that sampling extend into the wet season when flushing of CECs from the OWTS may increase their concentrations in both the lake but also the aquifers especially since residents use well water as their source of potable water. While this study is based in Florida, we strongly suspect that our findings and recommendations are applicable more generally as OWTS are used throughout the many karst regions of the world

Technical note Communication: Frequency ofchanging solid-walled cages does not affect pentobarbitone-induced sleeping time in rats and mice

The effects on pentobarbitone-induced sleeping time of daily cage changing or once every three days versus no changing for 15 days, was investigated in mice and rats, respectively. The animals were housed individually in cages with solid floors and a layer of wood shavings as bedding. Sleeping times were not affected by the frequency of cage changing

A questionnaire-based inventory of the orbital puncture method in the Netherlands

To contribute to the assessment of the degree of discomfort in rodents as caused by orbital puncture, we made an inventory in the Netherlands on the basis of an inquiry. Orbital puncture is being performed in laboratory rodents more than 45000 times a year. Usually, ether is used as anaesthetic. In about two-third of the institutes where orbital puncture is being performed, complications are noted. In I to 5 % of the animals punctured blindness can occur. In more than half of the instituteswhere orbital puncture is being performed there are objections to this technique. Which are essentially of an emotional/ethical nature

Wood gnawing in mice is not associated with open-field behaviour

The question was addressed whether in two strains of mice the amount chewed off supplied balsa wood is correlated with one of six measured aspects of open-field behaviour. For individual mice there were no significant correlations. This may either relate to a different nature of wood gnawing and open-field behaviour or to the observed low degree of stability of these behaviours in individual animals

Diterpenes from coffee beans decrease serum levels of lipoprotein(a) in humans: results from four randomized controlled trials

Objective: Unfiltered coffee raises serum LDL cholesterol in humans, owing to the presence of the diterpenes cafestol and kahweol. Norwegians with a chronic high intake of unfiltered coffee also had elevated serum levels of lipoprotein(a), an LDL-like particle which is insensitive toward dietary interventions. We now experimentally studied the influence of coffee diterpenes on lipoprotein(a) levels. Design: Four randomised controlled trials. Subjects: Healthy, normolipidemic volunteers. Interventions: Coffee, coffee oil, and pure diterpenes for 4-24 weeks. Main outcome measures: The circulating level of lipoprotein(a). Results: In 22 subjects drinking five to six strong cups of cafetiere coffee per day, the median fall in lipoprotein(a) was 1.5 mg/dL after two months (P=0.03), and 0.5 mg/dL after half a year (P>0.05), relative to 24 filter coffee drinkers. Coffee oil doses equivalent to 10-20 cups of unfiltered coffee reduced lipoprotein(a) levels by up to 5.5 mg/dL (P<0.05) in two separate trials (n=12-16 per group). A purified mixture of cafestol and kahweol, as well as cafestol alone, were also effective in reducing Lp(a) levels (n=10). Averaged over the four trials, each 10 mg/d of cafestol (plus kahweol)?the amount present in two to three cups of cafetiere coffee?decreased Lp(a) levels by 0.5 mg/dL or 4% from baseline values after four weeks (n=63). Conclusions: Coffee diterpenes are among the few dietary exceptions shown to influence serum lipoprotein(a) levels. However, the Lp(a)-reducing potency of coffee diterpenes may subside in the long run, and their adverse side effects preclude their use as lipoprotein(a)-reducing agents. Sponsorship: Supported by the Netherlands Heart Foundation through grant No. 900-562-091 of the Netherlands Organization of Scientific Research (NWO), plus supplemental funding by the Institute for Scientific Information on Coffee

Orbital bleeding in rats while under diethylether anaesthesia does not influence telemetrically determined heart rate, body temperature, locomotor and eating activity when compared with anaesthesia alone

The question addressed was whether orbital bleeding in rats, while under diethylether anaesthesia, affects their locomotor activity, body core temperature, heart rate rhythm and eating pattern. Roman High Avoidance (RHA) and Roman Low Avoidance (RLA) rats were used to enhance generalization of the results. Orbital bleeding when the rats were under diethylether anaesthesia was compared with diethylether anaesthesia alone. To take into account any effects of handling, the rats were also subjected to sham anaesthesia. The RHA rats urinated more during anaesthesia, needed more time to recover from the anaesthesia and showed a greater endocrine stress response to diethylether anaesthesia when compared with the RLA rats. During anaesthesia, the RHA rats showed a greater fall of body temperature and bradycardia than did the RLA rats. Diethylether anaesthesia reduced locomotor activity in the RHA rats, but had no effect in the RLA rats. In neither RHA nor RLA rats did anaesthesia plus orbital puncture, versus anaesthesia alone, influence body temperature, heart rate rhythm, locomotor and eating activity. The lack of effect of orbital puncture occurred both in the short term (within 2 h) and long term (within 48 hours) and thus this study indicates that orbital puncture had, at least with respect to variables measured in the present study, no effect superimposed on that of diethylether anaesthesia

Thyroid function and deiodinase activities in rats with marginal iodine deficiency

The hypothesis tested was whether marginal iodine deficiency for a period of 6 wk affects iodothyronine deiodinase activities in liver and brain of rats. Male rats were fed purified diets either deficient or sufficient in iodine; the diets were fed on a restricted basis (60% of ad libitum intake). Body weight gain of the two groups was comparable. Iodine deficiency was evidenced by increased thyroid weight (26%), reduced urinary iodine excretion (80%), and reduced plasma T4 concentrations (22%). Activities of liver type I and brain type III deiodinase were unchanged, but the activity of type II deiodinase in brain was increased (28%) in the iodine-deficient rats. Food restriction per se significantly lowered T3 (30%) and T4 (22%) concentrations in plasma and decreased type III deiodinase activity in brain (30%). These results indicate that in marginal iodine deficiency the activities of hepatic type I deiodinase and brain type III deiodinase are unchanged, whereas that of brain type II deiodinase is increased