Inhibition of diquat-induced lipid peroxidation and toxicity in precision-cut rat liver slices by novel antioxidants

The ability of the novel antioxidants U-74,006F and U-78,517G and a known antioxidant (N,N'-diphenyl-p-phenylenediamine, (DPPD)) to inhibit chemically induced (diquat dibromide) oxidative stress was examined in precision-cut liver slices. Previous studies in rat liver microsomes demonstrated the ability of these antioxidants to inhibit lipid peroxidation without preventing redox cycling of diquat. Diquat (1 mM) initiated lipid peroxidation in liver slices prepared from F344 rats. A 30-min preincubation with antioxidants inhibited formation of thiobarbituric acid reactive substances to control levels; ethane evolution, when elevated, was also inhibited by antioxidants. The toxicity of diquat (100 microM-3 mM) was evaluated in liver slices; 1 and 3 mM diquat caused decreases in intracellular K+ and intracellular LDH. Preincubation with antioxidants substantially decreased the toxicity of diquat as indicated by K+ and LDH. Diquat significantly decreased total glutathione levels in the slices; the antioxidants did not significantly inhibit this diquat-dependent effect. In summary, diquat, a compound which undergoes redox cycling and produces oxidative stress, was shown to produce lipid peroxidation, glutathione depletion, and toxicity in liver slices. Two experimental antioxidants, a 21-aminosteroid (U-74,006F) and a trolox-amine (U-78,517G) as well as a known antioxidant (DPPD) were shown to be effective in preventing lipid peroxidation and reducing the subsequent toxicity.     

Metastatic angiosarcoma with thrombocytopenia and intratumoral indium-111-platelet deposition.

A 66-yr-old woman with cutaneous angiosarcoma of the face presented with thrombocytopenia and metastases to the skeleton. Scintigraphic imaging with 111In-oxine-labeled autologous platelets demonstrated localization of radiolabeled platelets at sites of metastatic tumor. This imaging study suggests intratumoral destruction of platelets by the metastases of the malignant vascular tumor as the cause of the patient's thrombocytopenia.     

Epidemiological study ofCryptosporidium parvum in sera of persons from Germany

Summary In a seroprevalence study including 495 sera from persons of all age-groups, the presence of anti-Cryptosporidium parvum antibodies was evaluated in an enzyme immunoassay. Despite the fact thatC. parvum is only found in approximately 2% of patients with diarrhea in Germany, specific antibodies could be detected in 15.4% of all samples. This figure indicates that a substantial proportion of the German population has been confronted with this parasite and it raises the question of whetherC. parvum is a potential health risk to the general population. An erratum to this article is available at .     

Murine infection model for maintenance and amplification of Cryptosporidium parvum oocysts.

Propagation of Cryptosporidium parvum is problematic because in vitro development of the parasite is poor and animals are only briefly susceptible as neonates. At present oocysts of the parasite are usually procured by passage in neonatal sheep or cattle. In the present study, large numbers of oocysts of C. parvum could be isolated following infection of dexamethasone-treated adult C57BL/6 mice. The amount of immunosuppressive drug and the regimen of administration were critical for successful maintenance of the parasite, however. Routinely, 10 mice (age, 8 to 12 weeks) were injected four times on alternate days with 1.0 mg of dexamethasone, and the last injection was given on the same day as oral inoculation with 10(6) oocysts. By using a simplified procedure for oocyst purification from mouse feces, approximately 10(9) oocysts were obtained. This model is inexpensive and comparatively safe to handle, and the numbers of animals inoculated can be varied to obtain the required number of oocysts. Thus, this murine infection model would be a suitable alternative to the use of neonatal calves or sheep for efficient oocyst propagation.     

Paracoccidioides brasiliensis (Lutz, 1908) isolated by hemoculture in a patient with the acquired immunodeficiency syndrome (AIDS)]

A case of an AIDS patient with positive blood culture for Paracoccidiodes brasiliensis is reported. The patient was a 29-years-old male born in Nova Londrina (Paraná State, Brazil) who presented splenomegaly and fever of unknown origin. Three blood cultures were performed, each one of them for aerobic bacteria, mycobacteria and fungi. Cultures for aerobic bacteria and mycobacteria were negative. However, the yeast phase P. brasiliensis was isolated from two cultures in BHI agar, 20 days after inoculation in Negroni medium. The patient was classified in group V according to the Centers for Disease Control (CDC) criteria for AIDS, due to a Pneumocystis carinii pneumonia. Treatment was discontinued due to an individual decision of the patient on the second dose of amphotericin B. This antibiotic was replaced by ketoconazole in the daily dose of 800 mg. The patient died one year after the isolation of P. brasiliensis on blood culture.     

Spatial contrast sensitivity of the tree shrew

Spatial contrast sensitivity functions (CSFs) were measured for 3 tree shrews. Our two-alternative forced-choice discrimination paradigm required the animals to discriminate a vertical sine-wave luminance grating from a homogeneous field of the same size (16 degrees) and mean luminance (35 cd/m2). Spatial frequencies tested ranged from 0.1 to 2.0 c/deg and grating contrast was varied trial-by-trial using a modified staircase technique. Small between-subject variations in the shape of the CSFs appeared to be correlated with our estimates of refractive error for each animal. In general, the CSFs were of the typical band-pass type with peak sensitivity occurring at approximately 0.7 c/deg. Estimates of grating acuity derived from the CSFs ranged from 1.2 to 2.4 c/deg and are within the limitations set by the eye size and retinal anatomy of the tree shrew.     

Radiographic identification of simulated carious lesions in relation to fillings with Adaptic Radiopaque®

The purpose of the present study was to elucidate the possible significance of the radiopacity of a composite restorative material for the radiographic identification of filling deficiencies. Class III cavities of varied size and shape were prepared at 28 proximal surfaces of 14 extracted human canines. All cavities were filled with Adaptic Radiopaque®. Simulated secondary or recurrent carious lesions were produced in 16 of the cavities by insertion of small amounts of radiolucent wax prior to filling. Each tooth was radiographed under standardized conditions using 15 different angulations. The 210 radiographs were interpreted by three observers without knowledge of the distribution of the deficiencies. They made 78.7% correct diagnoses, 18.7% false positive and 2.6% false negative diagnoses. The sensitivity of the method was 95.4, but the specificity was only 56.5. The results indicate that radiopacity of a composite resin is of a certain, although limited, value in detecting secondary and recurrent carious lesions. Regarding the high number of false positive diagnoses the radiographic findings should as far as possible be verified by a clinical examination. A majority of the false positive diagnoses could be explained by an inhomogeneous structure of the fillings.     

A new anesthetic protocol in experimental ocular surgery in rabbits

The authors describe a new anaesthetic protocol for laboratory rabbits. The surgery consists in an extracapsular lens extraction with intraocular lens implantation in the bag. The anaesthetic protocol requires: an intravenous induction with ketamine (20.2 mg/kg +/- 5) and midazolam (0.65 mg/kg +/- 0.3) and after an oral endotracheal intubation with a simple method, and at last maintaining halothane anaesthesia with a concentration between 3 and 4%. 45 anaesthesia were performed: the average time of the anaesthesia was 77 min +/- 16. No rabbit died because of this anaesthesia. The anaesthesia was a success for the surgeon who could operate in the best working conditions.     

Computer Aided Monitor-Data Processing (CAMP)

A computer aided monitor-data processing system (CAMP-System) was developed in order to get a consistent and comprehensive database which can very precisely reflect intra-operative haemodynamic courses. The goal of the present study was to introduce a new method to scan and to gauge haemodynamic courses and to demonstrate its superiority over the traditional way of data processing based on a handwritten anaesthesia protocol. Methods. The computerized system was applied to a study which was designed to investigate the influence of ketanserin (K) vs. urapidil (U) on haemodynamic stability during cardiac operations. Twenty male patients scheduled for myocardial revascularization received either 20 mg K or 30 mg U. Heart rate, central venous, arterial and pulmonary artery pressures were measured and on-line recorded every 20 seconds by the computer record system. In the handwritten protocol these variables were registered at eight pre-defined time points. Computerized data processing (including artifact depletion and data condensation) was compared to the results evaluated from the handwritten protocol. Results. While the only significant differences in the handwritten protocol were slightly higher values of pulmonary artery pressures in group K, the computer analysis revealed a number of further differences. Higher maximum and a less stable time course of HR in group K in the pre-bypass phase and lower mean and standard deviation of MAP during cardiopulmonary bypass. Conclusion. Computerized data processing including automatic artifact suppression and data condensation was able to reveal differences in the course of haemodynamic variables that cannot be detected in a conventional handwritten protocol.