Seasonal cycle of nitrogen and phytoplankton biomass in a well-mixed coastal system (Eastern English Channel)

The hydrological structure of the French coastal part of the eastern English Channel is strongly linked with tidal regimes and riverine input. Two distinct water masses are separated by a frontal area and drift along the coast in SW–NE direction. These two water masses are well-mixed during the entire year. We studied the seasonal dynamic of nitrogenous nutrients, chlorophyll a and organic particulate carbon and nitrogen at two stations, characteristic of these water masses, during the year 1994. Results show (i) a winter stock of nitrate and ammonium, (ii) a pre-bloom period corresponding to the use of ammonium, (iii) a high bloom period of short duration using nitrate, (iv) a post-bloom period with little phytoplanktonic activity probably limited by nutrients other than nitrogen and (v) an autumnal period of reconstitution of stock. The essential difference between the two stations is the importance of winter stock of nutrients and of bloom chlorophyll a concentration, with the coastal station richer than the offshore one. An assumption about the nitrogen available for new production in this area gives a value of 57% of the winter stock of inorganic nitrogen.     

Localization of the CDKN4/p27Kip1 gene to human chromosome 12p12.3

CDKN4/p27Kip1 is a cyclin-dependent kinase (Cdk) inhibitor implicated in G1 phase arrest, which negatively regulates G1 phase progression in response to TGF, and might represent a tumor suppressor gene. We report here the chromosomal assignment of the human CDKN4 gene to chromosome 12p12.3 in close proximity to highly polymorphic microsatellite markers.     

Potentiation of antitumor effects of tumor necrosis factor α and interferon γ by macrophage-colony-stimulating factor in a MmB16 melanoma model in mice

The efficacy of systemic infusion of recombinant human macrophage-colony-stimulating factor (M-CSF) in combination with local treatment with human recombinant tumor necrosis factor (TNF) and mouse recombinant interferon (IFN) was studied in vivo on a subclone of B16 melanoma (MmB16) in mice. Short-term intravenous administration of M-CSF at a dose of 10⁶ units daily had no antitumor effect in vivo. Similarly, local treatment of tumor with TNF (5 g daily) did not produce any therapeutic effect. However, simultaneous administration of the same dose of TNF with IFN (1000 units daily) resulted in a synergistic effects manifested by the retardation of tumor growth. Addition of systemic infusion of M-CSF to the local therapy with TNF and IFN induced further augmentation of antitumor efficacy and delayed progression of MmB16 melanoma. The strengthened antitumor effect of combination therapy including M-CSF, TNF and IFN was most probably due to the increased release of monocytes from the bone marrow, their recruitment into the site of tumor growth and subsequent local stimulation of their antitumor activity.     

Histochemical enzyme pattern of microfilaria of Setaria cervi

The present study deals with the histochemical localization of glucose-6-phosphatase, malic dehydrogenase and aldolase in the microfilaria of Setaria cervi. Marked activity of glucose-6-phosphatase was observed in the cephalic cells, excretory and anal pores, G-cells and Innenk?rper. Malic dehydrogenase activity was noted throughout the body (including cuticle) of the microfilaria except for Innenk?rper. Intense aldolase activity was observed in the excretory pore and G-cells only. Muscle cells and anal pore were negative for this enzyme.     

Generation of human plaque-forming cells in culture: tissue distribution, antigenic and cellular requirements.

A system for the induction of specific, hemolytic plaque-forming cells from normal human lymphocytes in vitro (HcPFC) has been established and cells from various normal lymphoid tissues have been investigated. Normal values for anti-SRBC HcPFC responses in cultures of 107 Ficoll-Hypaque separated lymphocytes range from 2000 (bone marrow) to 7000 (spleen) and 15,000 (tonsillar and peripheral blood lymphocytes). HcPFC responses to ovalbumin were lower by factor of 2 to 4. Anti-SRBC as well as anti-ovalbumin responses required the cooperation of T lymphocytes and IgM-bearing B lymphocytes and the magnitude of the response was antigen dose dependent. Addition of adherent cells as well as of 2-mercaptoethanol enhanced the response. On the basis of the data obtained in experiments examining the role of B and T lymphocytes, a tentative model of cellular interaction has been postulated, suggesting a major role for antigen concentration in the modulation of the response via reactive T lymphocytes.     

Comparison of auramine-rhodamine B and acridine orange for staining of acid-fast bacteria.

In cooperation of 6 laboratories in Czechoslovakia and in the GDR, the efficiency of auramine-rhodamine B (AR) and acridine orange (AO) (short-time method) for staining of acid-fast bacilli was compared. Whereas a former comparison of AR and AO (original method) pointed out the superiority of AR, the investigation of both methods used as short-time procedures showed significantly more acid-fast rods after using AO. The number of "false positive" results was somewhat higher on AR staining. However the results depend not only on the method used but also on the procedure of staining and the optical equipment, and they are essentially influenced by the experience and proficiency of the microscopist. Taking into account the results of both studies both auramine-rhodamine B and acridine orange can be proposed for the staining of slides for microscopical detection of acid-fast rods. In case of AO, the short-time method is superior to the original long-time procedure.     

Effect of diamfenetide on experimental infections of Fasciola hepatica in lambs: anthelmintic and clinical investigations.

The activity of diamfenetide (N,N'-[oxybis(2,1-ethan diyloxy-4,1-phenylene)] bis acetamide) was studied in lambs experimentally inoculated with Fasciola hepatica. The drug was given orally at a dose level of 100 mg/kg either 1,3,5,7, or 9 weeks postinoculation. It was 100% effective 1, 3, and 5 weeks postinoculation, 73% effective 7 weeks postinoculation, and 57% effective 9 weeks postinoculation. Serum gamma-glutamyl transpeptidase activity remained normal in all lambs for 5 weeks after infection; it then began to increase in infected, untreated lambs at 6 weeks, and had increased 5- to 6-fold 9 weeks postinoculation in infected lambs. This enzyme activity was the most sensitive hematologic parameter used in this test to detect hepatobiliary damage by the parasite. The drug was well tolerated at the dose level used.     

应用气-质联用仪测定三种螺旋藻中的甾醇成分

应用GLC/MS联用仪对室内培养的钝顶螺旋藻(Spirulina platensis (Nordstedt) Geitler)、极大螺旋藻(S.maxima (Stechell & Gardiner) Geitler)和盐泽螺旋藻(S.subsalsa Oerst)的甾醇成分进行了测定。从钝顶螺旋藻和盐泽螺旋藻中共分出11个相同的甾醇组分:胆甾醇、胆甾烷醇、芸苔甾醇、麦角甾醇、海绵甾醇、菜子甾醇、豆甾醇、24-乙基-Δ~(5,7,22)-胆甾醇、β-谷甾醇、异岩藻甾醇和4α,23,24-三甲基Δ~(5,22)-胆甾醇;从极大螺旋藻中只分离出8个甾醇组分。其中胆甾醇含量最高。4α,23,24-三甲基-Δ~(5,22)-胆甾醇为蓝藻中首次报导。     

Labile conformation of type 2 Cu2+ centres in human ceruloplasmin.

1. The investigation of human ceruloplasmin by spectral methods (EPR and spectrophotometry) demonstrated that type 2 Cu2(+)-containing centres occur not in one, but in two stable forms, differing in EPR and optical spectra. The differential optical spectra of these forms were recorded and the differences in molar absorption coefficients determined. 2. By the EPR method, it was shown that both forms of these centres exist in the blood serum of control donors, as well as in the serum of patients. The relative content of these forms depends on the organism physiological state or on the presence of some pathological condition. 3. The ferroxidase activity of ceruloplasmin against hemoglobin was proved spectrophotometrically. The involvement of other serum proteins in this process cannot be ruled out. The conformational state of ceruloplasmin molecules plays an essential role in its oxidase activity.