Resting spore formation ofLeptocylindrus danicus (Bacillariophyceae) during short time-scale upwelling and its significance as predicted by a simple model

Resting spore formation during short time-scale upwelling and its significance were investigated in the field and by a simple theoretical model. Field observations of spore formation ofLeptocylindrus danicus were made off Izu Peninsula, Japan. A rapid increase in ratio of resting spore to vegetative cell numbers indicated thatL. danicus formed resting spores quickly as a response to nutrient depletion in the upwelled water, although only a very low number of resting spores was found in the upwelling. A simple model was constructed to investigate the possible advantages of spore formation during short time-scale upwelling. This showed that there is a critical time-scale for resting spore formation to be advantageous. The nutrient depletion period of the upwelling off Izu was shorter than the critical time-scale determined by the model. Rapid-sinking of resting spores may increase further the critical time-scale, unless spores return with upwelling water. For short time-scale upwelling, the vegetative cell may be better suited than the resting spore for enduring a short period of nutrient depletion. Contribution from Shimoda Marine Research Center, University of Tsukuba, No. 475.     

Immunological detection of low-density lipoproteins modified by malondialdehyde in vitro or in vivo

We describe an ELISA technique able to recognize malondialdehyde-modified low-density lipoproteins (LDL). For this purpose we produced antibodies to malondialdehyde-LDL, specific for the malondialdehyde modification of LDL; these antibodies recognized essentially malondialdehyde-LDL. Coating ELISA plates with the antibodies to malondialdehyde-LDL and using peroxidase-labelled antibodies to LDL, which reveal only apolipoprotein B, we obtained an accurate method of detecting malondialdehyde-modified apolipoprotein B. Preliminary studies demonstrated that this method allows the detection of lipoproteins containing malondialdehyde-modified apolipoprotein B in the serum of patients with cardiovascular diseases.     

Lack of association and linkage between HLA and familial polyposis coli

Summary We investigated possible association of and linkage between HLA and familial polyposis coli (FPC). In 182 individuals from 66 pedigrees of FPC and 108 individuals from a normal population, HLA-A,-B, and-C antigens were determined. When the frequencies of HLA antigens in 66 unrelated patients and in normal controls were compared, no association of FPC with HLA was observed. For the linkage analysis, HLA haplotypes of 17 affected sib pairs were investigated by the affected sib pair method. The number of pairs which shared two, one, and no haplotypes identical by descent was not significantly different from the number expected with random occurrence (P>0.95). Finally, seven families were analyzed using Morton's sequential test. A maximum lod score of-0.056 at a recombination fraction of 0.4, and a lod of-3.089 at a recombination fraction of 0.05 were obtained. Therefore, there is neither an association of nor linkage between FPC and HLA.     

Lung burden of green nickel oxide aerosol and histopathological findings in rats after continuous inhalation

There are few inhalation studies of nickel carcinogenesis. In this study, Wistar male rats were exposed to green nickel oxide (NiO(G)) aerosols (mass median aerodynamic diameter, 0.6 μm) for 7 h/d, 5 d/wk for up to 12 mo. The average exposure concentration was controlled at 0.3 and 1.2 mg/m³ during the exposure. For histopathological examination and measurement of the nickel concentration in rat organs, the rats were sacrificed at 3, 6, and 12 mo of exposure and 8 mo clearance period following 12 mo of exposure. The nickel content in rat lungs that was observed up to 2.6 mg after 12 mo exposure, was proportional to the exposure concentration during the exposure. The clearance of the nickel from the lungs was very slow and the biological half time was determined 7.7 mo. Although the rats were exposed continuously to NiO(G), for 12 mo and kept for 8 mo clearance period, there were no malignant tumors in any of the exposed animals.     

Electron microscopical findings with special reference to cancer in rats caused by inhalation of nickel oxide

A special exposure system was used for the inhalation of nickel oxide (NiO) aerosol by Wistar male rats. The median aerodynamic diameter and the geometric standard deviation were 1.2 μm and 2.2, respectively. A histopathological study of the rats was performed immediately, and at intervals of 12 and 20 mo after a 1-mo expsoure to NiO. Electron microscopy showed that localization of NiO particles was restricted to the lungs and that each particle had been engulfed by the alveolar macrophages. Type II pneumocytes and nonciliated bronchiolar epithelial cells (Clara cells), as well as numerous tubular myelin (surfactant) in the alveoli were prominent. In rats dissected after 12 mo, clusters of NiO particles were still present within the terminal bronchioli, alveolar walls, and lysosomes of the alveolar macrophages. Pools of tubular myelin were observed in the peribron-chial lymphatics. The Clara cells, which project into the lumen of bronchioli, showed active secretion and were filled with smooth en-doplasmic reticulum (SER) in the apical cytoplasm. In the experimental group sacrificed after 20 mo, one rat had papillary adenocarcinoma and two rats showed adenomatosis in the peripheral portion of the lung, but none in the upper respiratory tract.     

Disinfection of Aerosolized Pathogenic Fungi on Laboratory Surfaces: II. Culture Phase

The effect of several fungicides on laboratory surfaces contaminated with the culture (spore) phase of aerosolized Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum was ascertained. The culture (spore) phase was more resistant to the action of the fungicides than was the tissue (yeast) phase. The addition of a wetting agent increased the efficiency of several fungicides. The time required for disinfection with a given concentration of fungicide, or the concentration required to disinfect within a given time, can be determined by interpolating the plotted graphs.     

Effects of DSP-4 on monoamine and monoamine metabolite levels and on beta adrenoceptor binding kinetics in rat brain at different times after administration

Effects of DSP-4 on noradrenaline (NA), 3-methoxy-4-hydroxyphenyl glycol (MHPG), serotonin (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) levels and on beta adrenoceptor binding kinetics (Bmax and K_D) in rat hippocampus, cortex and hypothalamus were studied between 24 hours and 14 days after systemic administration. Beta adrenoceptor numbers in hippocampus and cortex, but not in hypothalamus, were significantly increased after DSP-4. No significant changes in K_D values were observed in hypothalamus, but significant increases in this parameter were measured in hippocampus and cortex. NA and MHPG levels were significantly decreased in all three brain regions, but MHPG/NA ratios were increased in hippocampus, decreased in cortex and unchanged in hypothalamus. Very prominent increases in 5-HIAA levels were observed in all three brain regions, but only at one day after DSP-4. The greatest increases in 5-HIAA levels occurred in the hippocampus, but this effect of DPS-4 appeared to be slightly diminished by pre-treatment with fluoxetine. In cortex and hippocampus 5-HT levels were slightly, but significantly decreased after DSP-4.     

White rhinoceros range size in the south-western Kruger National Park

White rhinoceros range size was ascertained telemetrically in the south-western Kruger National Park. The mean annual range size of territorial males was 9.86 km² compared to 22.83 km² for adult females. White rhinoceros females' summer wet season range was larger (21.44 km²) than the winter dry season range (11.64 km²). It is argued that abundant field-water during the wet season enables animals to range further from permanent water supplies and to utilize larger foraging areas. White rhinoceros have core areas in their individual ranges that usually are situated along riverbanks in the preferred grazing regions. These core areas also include some favourite resting spots on high-lying areas. White rhinoceros range sizes in the south-western Kruger National Park were similar to those of other reserves with comparable white rhinoceros densities. In the Umfolozi Game Reserve, which has a higher white rhinoceros density than the Kruger National Park, the individual ranges are much smaller.     

Detection of S-Phase Cells in Smear Cytology Using in Vitro Bromodeoxyuridine Labeling

A technique Is described for rapid detection of S-pha?e cells of tumor tissues in smear specimens using bromodeoxyuridine (BrdU) immunostaining. Mouse NR-S1 tumors and human tumor specimens were prepared for smear cytology after incubation in RPMI 1640 culture medium containing 200 μM BrdU at 37 °C under 3 atm for 1 hr. Samples were fixed in 70% ethanol for 30 min and used immediately or air dried for 30 min. Samples were then denatured in either 4 N HC1 or 0.07 N NaOH to prepare partially single-stranded DMA. Fixation with air drying for 30 min followed by 30 min in 70% ethanol and 1 min denaturation with 0.07 N NaOH resulted in satisfactory staining quality. Cultured tumor specimens were processed for routine paraffin sections after smears were made for cytology. The labeling indices of the smear specimens and of the paraffin sections gave similar results. This technique should be useful in evaluating the cell proliferative potential of tumor tissue in smear cytology without processing paraffin sections.