Damage to protein synthesis concurrent with lipid peroxidation in rat liver slices: effect of halogenated compounds, peroxides, and vitamin E1

Protein synthesis and lipid peroxidation were evaluated in rat liver slices incubated in the presence of oxidants and protein synthesis inhibitors. Protein synthesis by rat liver slices was evaluated by [3H]leucine incorporation into the trichloroacetic acid (TCA)-insoluble material, and lipid peroxidation was evaluated by thiobarbituric acid-reactive substances (TBARS) released into the incubation medium. Protein synthesis inhibition by bromotrichloromethane (BrCCl3) or t-butyl hydroperoxide (t-BOOH) depended on the incubation time and oxidant concentration. [3H]Leucine incorporation was decreased to 20 and 47% of control values and TBARS were enhanced from the control value of 16.9 to 45.3 and 62.5 nmol/g of liver by incubation for 1 h with 1 mM BrCCl3 and t-BOOH, respectively. Following incubation, both protein synthesis damage and lipid peroxidation were decreased in control and oxidant-treated slices prepared from rats injected with 200 mg of DL-alpha-tocopherol/kg of body wt. Release of lactate dehydrogenase was not enhanced by oxidant treatment. Protein synthesis inhibitors reversibly decreased [3H]leucine incorporation, but the effect of oxidants on protein synthesis was irreversible. Cumene hydroperoxide and methyl ethyl ketone peroxide, but not hydrogen peroxide, damaged protein synthesis and induced lipid peroxidation. The ability of carbon tetrabromide, benzyl chloride, bromoform, bromobenzene, carbon tetrachloride, chloroform, dichloromethane, and bromochloromethane to inhibit protein synthesis was correlated with their ability to induce lipid peroxidation, and with their LD50. The results suggest that oxidant-induced lipid peroxidation and protein synthesis damage occurred concurrently, and that protein synthesis inhibition may be involved in cell injury or death mediated by free radicals.     

In situ hybridization of semithin Epon sections with BrdU labelled oligonucleotide probes

Summary We recently described a nonradioactive method for in situ hybridization with 5-bromo-2-deoxyuridine (BrdU) labelled oligonucleotide probes. An antibody to BrdU and immunocytochemistry were used in order to detect the hybridization signal. We have now applied this method to semithin Epon sections, in order to hybridize consecutive sections through single cells with different probes and to stain them with antibodies to neuropeptides. It could be shown that Epon embedding preserves mRNA well. In the present study we used a BrdU labelled synthetic oligonucleotide probe complementary to a fragment of the vasopressin precursor and an antibody to Arg-vasopressin. Vasopressin mRNA was demonstrable in a fraction of the vasopressin immunoreactive neurons in the magnocellular nuclei. In addition some of the magnocellular neurons showed either hybridization or vasopressin immunostaining only, perhaps indicating different stages of synthetic and secretory activity. The method described seems to be a valuable tool for studying synthetic activity in peptidergic neurons on a single cell level. The method might also have potential for in situ hybridization on the electronmicroscopical level.     

A ‘Problematic fossil’ revealed:Pycnoporidium ? eomesozoicum Flügel, 1972 (Late Triassic,Tethys)—not an enigmatic alga but a strophomenid brachiopod (Gosaukammerella n.g.)

Summary The microproblematicumPycnoporidium ? eomesozoicum Flügel, 1972, from Upper Triassic reefs of the Alpine-Mediterranean region, Turkey Oman and Iran (originally interpreted as possible alga) represents the type species of a new strophomenid brachiopod genus (Gosaukammerella n.g.). The genus is characterized by a very small, millimeter-sized plano-convex shell, whose ventral valve is attached to the substratum (mainly sponges) by symmetrically arranged outgrowths developing from a pseudopunctate, lamellose foliated shell wall and composed of densely spaced subparallel ‘tubes’ comparable with productide spines secreted by papillose extensions of the mantle.Gosaukammerella seems to be the only reliable candidate for the existence of post-Paleozoic strophomenid (productid ?) brachiopods. Gosaukammerella eomesozoica is restricted to possibly cryptic, shaded reef environments inhabited predominantly by sponges serving as substrates for micromorphic brachiopods.     

Extremely short 20-33 nucleotide introns are the standard length in Paramecium tetraurelia.

Paramecium tetraurelia has the shortest known introns as its standard intron length. Sequenced introns vary between 20 and 33 nucleotides in length. The intron sequences were discovered in genomic sequences coding for a variety of different proteins, including phosphatases, kinases, and low-molecular weight GTP-binding proteins. All intron sequences begin with the conserved dinucleotide GT and end with the conserved dinucleotide AG. The sequences are more AT rich than the Paramecium coding sequences. The identified sequences were confirmed as introns by sequencing several cDNA fragments. We report here analysis of the characteristics of 50 separate introns, including size, base composition, and a consensus sequence.     

Use of recombinant interferon-α in Human Immunodeficiency Virus (HIV)-infected individuals

Rationale and objective Interferon alpha (IFN-) has anti-retroviral activity and is a possible HIV infection-limiting factor. The aim of this work is to prevent or delay disease progression in asymptomatic Human Immunodeficiency Virus (HIV) carriers.Design and interventions Recombinant IFN alpha-2b (3×10⁶ IU 3 times weekly) was compared. to no treatment (control) in a randomized trial. Endpoints were: (i) appearance of any CDC group IV symptoms and (ii) disease progression (which excluded shifts to group IVC2 or reversible IVA, or IVB). The trial lasted from October 1987 to February 1992.Setting The trial was performed at the Santiago de las Vegas sanatorium, a specialized institution for the care of HIV-infected and AIDS patients.Population Subjects were anti-HIV-1 seropositive, Western blot-confirmed, asymptomatic (CDC group II), or with generalized lymphadenopathies (CDC group III). The groups had 79 (control) and 71 (IFN) patients.Main results Long-term IFN- treatments significantly reduced the proportion of patients who shifted to any group IV (control: 46/79; IFN: 14/71;p<0.001) or developed AIDS (control: 27/79; IFN: 12/71;p<0.05). IFN also delayed progression to AIDS (95% confidence interval for 0.5 probability of progression) from 67–83 to 116–180 months after infection. The IFN group had significantly less opportunistic infections and non-infectious complications. CD4 cell count and hemoglobin decreased in the control but not in the IFN group. Fewer IFN-treated patients developed positive serum HIV antigen detection.Conclusion IFN alpha treatment during the early stages of infection seems to be beneficial to the patients.Abbreviations CI confidence interval - AIDS Acquired Immunodeficiency syndrome - HIV Human Immunodeficiency Virus - IFN Interferon - CDC Center for Disease Control (USA) - SD standard deviation     

Fluorescent detection-polymerase chain reaction (FD-PCR) assay on microwell plates as a screening test for salmonellas in foods

This study evaluates a polymerase chain reaction assay coupled with a fluorescent detection in microwell plates for salmonellas in food samples. Chelex 100-extracted cultures and bulk and processed food samples were used as templates for a PCR assay in microwell plates, with a primer pair that amplifies a 206 bp segment of IS 200 . The PCR products were then denatured by heat and transferred to CovaLink NH plates (Nunc) to which capture oligonucleotides were covalently bound. Hybridization was performed for 1 h at 55°C, the microwells were washed and an alkaline phosphatase-labelled probe, complementary of an internal sequence of the PCR product, was added. After stringent washes, 100 μl of 1 mmol 1^-1 AttoPhos^TM (JBL Scientific) was then added to the wells and the fluorescence measurement system (Millipore). The level of detection of the assay was as low as 1–10 cfu. A total of 172 food samples were tested, both by culture and FD-PCR. Of these 53 were culture positive and 119 culture negative. The sensitivity of the FD-PCR assay was 100% and the specificity was 90.1%. Positive and negative predictive values were 82.8 and 100%, respectively. Based on the results obtained in this study it appears that the FD-PCR. assay described here can be useful to screen a large number of food samples for contamination by salmonellas.     

Intercellular junctions in the uterine epithelium of Salamandra salamandra (L.) (Amphibia,Urodela)

Summary Intercellular junctions in the uterine epithelium of the ovoviviparous urodele Salamandra salamandra were studied in pregnant and non-pregnant females by freeze-fracture technique. Junctional complexes consist of zonulae occludentes (tight junctions) and numerous maculae adhaerentes (desmosomes); z. adhaerentes and nexuses (gap junctions) could not be identified. Tight junctions are of the flexible type exhibiting loosely interconnected fibrils. The fibrillary network appears stretched more often in pregnant females possibly due to the mechanical stress of pregnancy. The structure and occurrence of the junctions identified, especially that of the tight junctions, is discussed with regard to the functions of the uterus during pregnancy.Zusammenfassung Mit Hilfe der Gefrierbruchtechnik wurden im Uterus-epithel trächtiger und nichtträchtiger Feuersalamanderweibchen (Salamandra salamandra) Zonulae occludentes und Maculae adhaerentes, jedoch keine Z. adhaerentes sowie Nexus identifiziert. Die Z. occludentes sind flexibel. Ihr fibrilläres Netzwerk ist bei trächtigen Weibchen öfter gestreckt; das ist möglicherweise auf die stärkere Ausdehnung des Uterusgewebes während der Trächtigkeit zurückzuführen. Das Vorkommen der verschiedenen Kontakt-strukturen, namentlich das der Z. occludentes, wird im Hinblick auf die Funktionen des Uterus während der Trächtigkeit diskutiert.We are indebted to Mrs. K. Ott for excellent technical assistance and to Miss Dr. U. Beigel for linguistic help     

Chromium content in human milk,Cow's milk,and infant formulas

Chromium was measured by Electrothermal Atomic Absorption Spectrometry in human milk, cow's milk, and infant formulas. The mean levels found were 1.56, 0.83, and 4.84 (13%) μg/L, respectively. According to our data, the daily intake for the Spanish neonates is lower than the Recommended Dietary Allowances (RDAs) (10–40 μg/d) for this element.