Effects of water dilution, housing, and food on rat urine collected from the metabolism cage

The objective of the study reported here was to investigate three factors that may affect the amounts of water consumed and urine excreted by a rat in the metabolism cage: water dilution, housing, and food. Young F344/N rats (eight per group) were used for all experiments. Food was withheld from rats before each 16-h urine collection, then rats were transferred into a metabolism cage. For trial A (water dilution), urine was collected from rats supplied with dyed water (0.05%, vol/vol). This was repeated three times over a 2-week period. Dye in water or urine was quantified, using a spectrophotometer. For trial B (housing), rats were individually housed in wire cages for 3 weeks before the first urine collection. Then they were group housed in the solid-bottom cage (four per cage). After 2 weeks of acclimation, urine collection was repeated. For trial C (food), one group of rats was provided with food, the other was not, during urine collection. About 8% of urine samples of small volume (< or = 3 ml) from trial A were contaminated with drinking water up to 13% of volume. The average urine volume associated with individual housing was approximately twice as large as that associated with group housing. When food was provided during urine collection, rats consumed similar amounts of water but excreted significantly smaller amounts of urine than did rats without food. It was concluded that water dilution of a urine sample from a sipper bottle is relatively small; rats individually housed in wire caging before urine collection can consume and excrete a larger quantity of water, compared with rats group housed in solid-bottom cages; and highly variable urine volumes are, in part, associated with lack of access to food during urine collection.     

Peripheral Blood Lymphocyte Typing as a Useful Tool to Objectify the Oral Mucosa Patch Test in the Diagnosis of Allergic Contact Mucositis to Nickel

Nickel (Ni) exposure through the intestinal mucosa may cause a hypersensitivity reaction recently defined as allergic contact mucositis (ACM). This condition is identifiable by the oral mucosa patch test (omPT), a qualitative and subjective examination that requires clinical expertise. Our aim was to evaluate if a peripheral blood lymphocyte typing performed before and after the omPT for Ni may be able to objectify this examination for diagnostic purposes. Thirty patients with symptoms referable to the ingestion of Ni-rich foods were subjected to omPT for Ni. Before and after the omPT, each patient underwent blood sampling for the typing of total lymphocytes and their subsets (T, T helper or Th, T cytotoxic or Tc, B, natural killer or NK). Statistical analysis was performed by Student t test and receiver operating characteristic (ROC) curve analysis. According to the omPT outcomes, 18 patients were defined as Ni-sensitive and the remaining 12 as controls. In Ni-sensitive patients, the number of total, T, Th, Tc, and B lymphocytes/μL whole blood increased after the omPT (p?<?0.0001 for the first three, p?=?0.0004 and p?=?0.0001 for the last two lymphocyte types). No omPT-dependent lymphocyte increase was observed in controls. The post/pre omPT cell ratio, especially if calculated for Th lymphocytes, appears to be an effective index for diagnostic purposes (sensitivity?=?100 %, specificity?=?83.3 %, Youden index?=?0.833, area under curve (AUC)?=?0.926, p?<?0.0001). In conclusion, the peripheral blood lymphocyte typing with calculation of post/pre omPT cell ratio has the potential to support the omPT in diagnosing ACM, with the advantage of providing quantitative and objective data.     

Coupling of organotypic brain slice cultures to silicon-based arrays of electrodes.

Fetal or early postnatal brain tissue can be cultured in viable and healthy condition for several weeks with development and preservation of the basic cellular and connective organization as so-called organotypic brain slice cultures. Here we demonstrate and describe how it is possible to establish such hippocampal rat brain slice cultures on biocompatible silicon-based chips with arrays of electrodes with a histological organization comparable to that of conventional brain slice cultures grown by the roller drum technique and on semiporous membranes. Intracellular and extracellular recordings from neurons in the slice cultures show that the electroresponsive properties of the neurons and synaptic circuitry are in accordance with those described for cells in acutely prepared slices of the adult rat hippocampus. Based on the recordings and the possibilities of stimulating the cultured cells through the electrode arrays it is anticipated that the setup eventually will allow long-term studies of defined neuronal networks and provide valuable information on both normal and neurotoxicological and neuropathological conditions.     

Linkage of a Triple Helix-Forming Oligonucleotide to Amsacrine-4-carboxamide Derivatives Modulates the Sequence-Selectivity of Topoisomerase II-Mediated DNA Cleavage

Abstract

Amsacrine-4-carboxamide-oligonucleotide conjugates were synthesized and studied for their capacity to form DNA triple helices and to alter human topoisomerase II binding and cleavage properties. The intercalating agent was attached to the 3′- or the 5′-end of a 24 nt triple helix-forming oligonucleotide via linkers of different lengths. The stability of these DNA triple helices was investigated by gel retardation and melting temperature studies using a synthetic 70 bp DNA duplex target. The effect of the conjugates on DNA cleavage by topoisomerase II was evaluated using the 70 bp duplex and a 311 bp restriction fragment containing the same triple helix site. The conjugate with the amsacrine derivative linked to the 3′ end of the TFO via a hexaethylene glycol linker modulates the extent of DNA cleavage by topoisomerase II at specific sites.     

Transfusion-transmitted diseases other than AIDS and hepatitis.

Although the major diseases transmitted by transfusion today are AIDS and hepatitis, many others also are known. These include CMV, syphilis, Chagas disease, babesiosis, parvovirus B19, malaria, Epstein-Barr infection, and many others that have been reported only once or twice. Reducing the risk of transfusion-transmitted diseases is a problem for donor centers where donor screening and laboratory testing for possible carriers is undertaken. Physicians should be aware that the potential for disease transmission is always present when transfusions are administered.     

Exercise training and responsiveness of isolated coronary arteries.

Exercise is associated with release of catecholamines and vasoactive intestinal polypeptides. Recurrent exposure to catecholamines modifies the sensitivity of adrenoceptors. To test the hypothesis that exercise training may affect the sensitivity of the epicardial coronary arteries, we performed studies on isolated coronary arteries from male dogs capable of running on a treadmill. The animals were separated randomly into two groups: sedentary and exercise training. After 11 wk, rings of left circumflex and left anterior descending coronary arteries were studied in vitro. Contractions to alpha 1-adrenergic agonists (norepinephrine and phenylephrine) were not affected by exercise training. During contractions with prostaglandin F2 alpha, endothelium-dependent relaxations to alpha 2-adrenergic agonists (norepinephrine and UK 14304) were not reduced significantly by exercise training. The concentration-relaxation curves to beta-adrenergic agonists (norepinephrine, isoproterenol, and epinephrine) were shifted to the right after training. The concentration-response curves to vasoactive intestinal polypeptide, but not that to substance P, were shifted to the right in rings with endothelium from exercise-trained animals. These findings demonstrate a decrease in responsiveness of canine vascular smooth muscle to beta-adrenergic agonists and to vasoactive intestinal polypeptide after exercise training.