Platelet activating factor induces expression of early response genes c-fos and TIS-1 in human epidermoid carcinoma A-431 cells

The effect of platelet activating factor (PAF) on the induction of early response genes was investigated in A-431 cells (human epidermal carcinoma cells). PAF induced a transient expression of c-fos and TIS-1 mRNA in a time- and dose-dependent manner. As low as 10(-10) M PAF caused detectable expression of these genes with a maximum observed at 10(-7) M. In the presence of cycloheximide, increases in the gene expression were noticeable at 20 min and peaked between 30-60 min. A lack of induction with lyso-PAF, an inactive PAF metabolite, confirmed the specificity of PAF towards this expression. The cells pretreated with CV-6209, a PAF receptor antagonist, did not show any induction of these genes by PAF. It is concluded that PAF causes induction of the early response genes c-fos and TIS-1 in a structurally specific and receptor dependent manner. This finding offers a new role for PAF at the nuclear level and may have important implications in the long term effects of PAF in pathophysiological conditions.     

Seasonal carbon isotope discrimination in a grassland community

Summary Grassland communities of arid western North America are often characterized by a seasonal increase in ambient temperature and evaporative demand and a corresponding decline in soil moisture availability. As the environment changes, particular species could respond differently, which should be reflected in a number of physiological processes. Carbon isotope discrimination varies during photosynthetic activity as a function of both stomatal aperture and the biochemistry of the fixation process, and provides an integrated measure of plant response to seasonal changes in the environment. We measured the seasonal course of carbon isotope discrimination in 42 grassland species to evaluate changes in gas exchange processes in response to these varying environmental factors. The seasonal courses were then used to identify community-wide patterns associated with life form, with phenology and with differences between grasses and forbs. Significant differences were detected in the following comparisons: (1) Carbon isotope discrimination decreased throughout the growing season; (2) perennial species discriminated less than annual species; (3) grasses discriminated less than forbs; and (4) early flowering species discriminated more than the later flowering ones. These comparisons suggested that (1) species active only during the initial, less stressful months of the growing season used water less efficiently, and (2) that physiological responses increasing the ratio of carbon fixed to water lost were common in these grassland species, and were correlated with the increase in evaporative demand and the decrease in soil moisture.     

Some factors that influence the plasma lipoprotein 1H NMR spectra of normal and cancer patients: an oncolipid test?

Selected factors have been evaluated in order to determine their influences on the plasma lipoprotein proton NMR spectra of normal and cancer patients. The variables were donor''s diet (fasting/non-fasting), temperature and time of sample storage, processing procedure, centrifugation speed, and water pre-saturation time. Plasma samples from fasting individuals that were placed immediately on ice, spun at 1,000 and 3,000 g for 15 minutes, and the proton NMR spectrum acquired with the Carr-Purcell Meiboom-Gill (CPMG) pulse sequence, using a two-second water pre-saturation time, consistently gave reproducible results. Resonances attributed to lactate were minimized under these processing conditions. Centrifugation speed and pre-saturation time did not affect the average line width; however, donor fasting state, processing temperature, and storage time did alter the line width. Most important, blood chemistry analysis revealed an inverse correlation between triglyceride levels and average methyl and methylene line widths. Thus, these factors alone caution against the indiscriminate use of proton NMR spectra to differentiate plasma from normal and cancer patients.     

Glucocorticoid effects on zinc transport into colostrum and milk of lactating cows

Colostrum Zn concentrations were measured in eight randomly selected Holstein dairy cows. Overall mean Zn concentrations were highest within 12 h postpartum (257 +/- 14 microM, mean +/- SEM), fell to 141 +/- 8 microM by 24 h, and then declined at a linear rate of 30 microM/d during the following 48 h. Zn concentrations at 3 d (82 +/- 5 microM) were not different from 150-d milk samples (72 +/- microM). In a second experiment, 32 early-gestation cows were blocked by stage of lactation into four groups in a randomized block design and injected with 0, 15, 30, or 45 mg of dexamethasone. Milk and blood samples were collected at 0, 12, and 24 h after injection and analyzed for Zn, and for fat, protein, and lactose in milk. Cows administered 0 and 15 mg of dexamethasone showed no difference in milk Zn concentrations compared to pretreatment measurements; however, milk Zn concentrations in cows administered 30- and 45-mg doses increased significantly. Plasma cortisol decreased in the dexamethasone-treated cows. Plasma Zn and milk fat, protein, and lactose did not change. These data indicate that glucocorticoids can mediate Zn uptake and transport by the mammary glands of lactating cows and suggest that the high Zn concentration in colostrum could be a result of the preparturient surge of cortisol.     

Three new species of Bychowskyella Achmerow, 1952 (Monogenea) from Peninsular Malaysia

Three new and one previously described species of Bychowskyella Achmerow, 1952 were collected from the gills of four species of freshwater catfish in Peninsular Malaysia. They are Bychowskyella teysmanni n. sp. from Clarias teysmanni (Bleeker, 1857) (Clariidae), Bychowskyella sisoris n. sp. from Glyptothorax major (Boulenger, 1894) (Sisoridae), Bychowskyella baueri n. sp. from Silurichthys hasselti (Bleeker, 1858) (Siluridae), and Bychowskyella tchangi Gussev, 1976 from Clarias macrocephalus Gunther, 1864 (Clariidae). B. teysmanni n. sp. differs from B. tchangi in having two pairs of large marginal hooks. B. sisoris n. sp. is unique in possessing two onchia, while B. baueri n. sp. differs from previously described Bychowskyella species in the structure of the dorsal onchium. C. macrocephalus is a new host record for B. tchangi in Peninsular Malaysia.     

Purification and properties of intracellular fructosyl transferase fromAureobasidium pullulans

Intracellular frustosyl transferase was purified fromAureobasidium pullulans C-23 by ethanol fractionation, CM-Sephadex chromatography and preparative disc gel electrophoresis. It was shown to be homogeneous on disc polyacrylamide gel electrophoresis, with a molecular size of 190kDa. The pI value of the enzyme was about 3.7. The enzyme has aK _m value of 0.43 mM for sucrose and was optimally active at pH 5.0 and 60°C. The enzyme was stable from pH 2.5 to 12. It was almost completely inhibited by 5mM Hg²⁺ but was not significantly affected by other cations. The transferase was inactivated by treatment with the tryptophan-specific reagentN-bromosuccinimide and the tyrosine-specific reagent, I₂, suggesting that tryptophan and tyrosine residues are probably located at or near the active site of the enzyme.     

Audit of compliance with antenatal protocols.

OBJECTIVE--To assess the implementation of action protocols dictated by antenatal risk factors noted at the initial (booking) antenatal visit. DESIGN--Retrospective study of 2000 women delivered between 1 March 1990 and 29 March 1991. SETTING--Maternity department of a district general hospital supporting a multiethnic population in inner London. MAIN OUTCOME MEASURES--Comparison of clinical actions performed against those dictated by the department''s protocols. Analysis according to clinical importance, gestation at booking, maternal age, parity, birth order, ethnic origin, and certainty of gestational age. RESULTS--Interobserver agreement between the two auditors was good (kappa statistic for risk factors detected, 0.78; for actions generated, 0.80). Of the 15,658 actions dictated by department protocols, 3673 (23.5%) were actually performed by the clinicians. The 63 combinations of risk factors and actions believed by consultants to be of particular clinical importance had an action rate of 28.3% compared with 18.6% for those considered less important (p < 0.001). Mothers who first visited the hospital antenatal clinic at or before 24 weeks'' gestation had 25.2% of relevant protocols fulfilled (p < 0.001). Compliance was significantly improved in women aged 36 or over (32.4%), black women (24.9%), and cases of uncertain gestation (24.5%). Parity and birth order were not associated with an altered action rate. Ethnic origin deemed as "other" (than white, black, Asian, or oriental) or "unknown" was associated with poor compliance (19.3%). CONCLUSIONS--Compliance to a set of agreed protocols was poor even though a computer system was available and a protocol manual had been distributed. Protocols were more likely to be implemented in women who booked early and in some groups of women deemed at high risk including older mothers, black women, and those denoted as having uncertain gestational age.     

Carbonisation of oil palm trunks at moderate temperatures

Thousands of tonnes of dry oil palm trunks will be produced annually in Malaysia after about 1990. A project was initiated to study the feasibility of converting palm trunks into charcoal. Carbonisation was done at terminal temperatures of 400–550°C with holding times of 1–3 h and at two heating rates. From laboratory-scale pyrolysis studies, it was found that holding time does not affect the quantity and quality of the charcoal produced, while heating rate has a minor influence. However, as terminal temperature increases, both yield and volatile content decrease while the fixed carbon content increases. The calorific value and ash contents are independent of the parameters studied and their respective values are 4032 kcal/kg and 37.2%. Since the calorific value is low and the ash content high, it is concluded that oil palm trunks are not suitable for the production of charcoal fuel.     

Binding protein dependent transport of C4-dicarboxylates in Rhodobacter capsulatus

The characteristics of malate transport into aerobically grown cells of the purple photosynthetic bacterium Rhodobacter capsulatus were determined. A single transport system was distinguished kinetically which displayed a K_t value of 2.9 ± 1.2 μM and V_max of 43 ± 6 nmol · min^-1 · mg^-1 protein. Competition experiments indicated that the metabolically related C4-dicarboxylates succinate and fumarate are also transported by this system. Malate uptake was sensitive to osmotic shock and evidence from the binding of radiolabelled malate and succinate to periplasmic protein fractions indicated that transport is mediated by a dicarboxylate binding protein. The activity of the transport system was studied as a function of external and internal pH and it was found that a marked activation of uptake occurred at intracellular pH values greater than 7. The use of a high affinity binding protein dependent system to transport a major carbon and energy source suggests that Rhodobacter capsulatus would be capable of obtaining growth sustaining quantities of C4-dicarboxylates even if these were present at very low concentrations in the environment.     

Lymphocyte activation and serine-esterase induction following recombinant interleukin-2 infusion for lymphomas and acute leukaemias

Summary C57BL mice inoculated with radiation leukemia virus (RadLV) develop preleukemic cells long before the onset of leukemia. These cells are potentially immunogenic but fail to elicit an immune response in the host because of the appearance of virus-specific suppressor T cells. We have studied the effect of polysaccharide K (PSK) on the generation of RadLV-specific cell-mediated immune responses in vitro. Long-term exposure to PSK in culture potentiated the ability of immunized T cells to respond to a RadLV-induced lymphoma. It also abrogated the suppressive activity of suppressor T cells and simultaneously boosted the ability of reactive T cells to respond. The dual immunostimulating activity of PSK resulted in the generation of T cytotoxic lymphocytes that could lyse lymphoma cells in vitro. The results suggest that PSK could be used as a prophylactic immune response modifier in preleukemia.