Prolactin can stimulate general protein synthesis in human breast cancer cells (MCF-7) in long-term culture

Prolactin significantly stimulated protein synthesis rates in a human breast cancer cell line, MCF-7. Total protein per culture also increased to 148% of controls. Proteins precipitated from cell homogenates at pH 4.65 in the presence of calcium ions were resolved by sodium dodecyl sulfate- polyacrylamide gel electrophoresis. The specific radioactivity for almost every polypeptide band increased as a result of protlactin treatment. Cell-type specificity for this prolactin action was indicated by the failure of two other human cell lines (HBL-100 and HEL) to respond similarly. This report is the first demonstration that prolactin has the capability to stimulate general protein synthesis in human breast cancer cells in long-term culture.     

Deoxyribonucleic Acid Relationships Among Marine Vibrios

The deoxyribonucleic acid (DNA) relationships of 80 strains identified either as Vibrio parahaemolyticus, V. alginolyticus, and V. anguillarum, or as allied marine vibrios were delineated by DNA-DNA competition experiments as well as by measuring the thermal stabilities of the DNA-DNA duplexes formed in direct binding studies. The tested strains included isolates from Japan, Europe, and the United States. The V. parahaemolyticus and V. alginolyticus groups showed an average of 67% homology to one another and 30% to strains of V. anguillarum. Significantly, a number of the isolates from the Pacific Northwest which had been previously identified as V. parahaemolyticus based on morphological, biochemical, and serological evidence were shown either to be strains of V. anguillarum or to belong to as yet unnamed groups. Most strains isolated from diseased salmon in the Pacific Northwest proved to be virtually identical with V. anguillarum type C by DNA homology experiments, thereby differentiating them from similar strains isolated from diseased herring and occasionally from salmon. The latter Pacific Northwest isolates fell into two distinct genotypic groups. A plot of the per cent homology by competition versus the difference in the thermal stabilities of heterologous and homologous duplexes (DeltaT(m,e)) between the same DNA species shows a linear decline in homology of 4.25% per degree of DeltaT(m,e). The use of this relationship for estimating the percentage of the mispaired bases distinguishing DNA preparations directly from competition experiments is discussed.     

Time-dependent changes of calcium influx and efflux rates in rabbit skeletal muscle sarcoplasmic reticulum

Unfractionated and low buoyant density sarcoplasmic reticulum vesicles released calcium spontaneously after ATP- or acetyl phosphate-supported calcium uptake when internal Ca²⁺ was stabilized by the use of 50 mM phosphate as calcium-precipitating anion. This spontaneous calcium release could not be attributed to falling Ca²⁺ concentration outside the vesicles (Ca₀²⁺), substrate depletion, ADP accumulation, nonspecific membrane deterioration or the attainment of a high vesicular calcium content. Instead, spontaneous calcium release was directly proportional to Ca₀²⁺ at the time that calcium content was maximal. A causal relationship between high Ca₀²⁺ and spontaneous calcium release was suggested by the finding that elevation of Ca₀²⁺ from less than 1 μM to 3–5 μM increased the rate and extent of calcium release.The spontaneous calcium release was due both to acceleration of calcium efflux and slowing of calcium influx that was not accompanied by a significant change in the rate of ATP hydrolysis. Neither reversal of the transmembrane KCl gradient nor incubation with cation and proton ionophores abolished the spontaneous calcium release. The persistence of calcium release under conditions where the membrane was permeable to both anions and cations makes it unlikely that this phenomenon is due to a changing transmembrane potential.     

The latex agglutination test versus counterimmunoelectrophoresis for rapid diagnosis of bacterial meningitis

A modified latex agglutination (LA) test was compared with Gram-staining and counterimmunoelectrophoresis (CIE) for the rapid detection in the cerebrospinal fluid (CSF) of antigen to Haemophilus influenzae type b, Neisseria meningitidis groups A, B and C, Escherichia coli K1, Streptococcus pneumoniae and group B streptococci, seven frequent causes of bacterial meningitis in children. Of 50 CSF samples from patients with culture-proven bacterial meningitis 90% were correctly shown by the LA test to contain antigen of the responsible organism. Gram-staining revealed organisms in 80% of 45 of these samples. In 75% of the 40 samples that were of sufficient volume for CIE, positive results for the appropriate antigen were obtained. The concentration of antigen detected in the CSF by the LA test varied from undetectable to 800 000 ng/ml. Patients with a high concentration (more than 2000 ng/ml or a positive result at dilutions of CSF over 1/8) were significantly more likely to have a poor response to therapy (two died and two had persistent pleocytosis or bacteria in the CSF) than patients with a lower concentration (4/16 v. 0/18, P < 0.05). After appropriate therapy was begun the concentration of antigen fell dramatically, but measurable amounts of antigen persisted in the CSF for up to 6 days. The LA test detected bacterial antigen at concentrations 2 to 70 times below the lower limit detected by CIE. In seven additional patients who had received antibiotics before lumbar puncture was performed the LA test detected antigen from meningitis-causing bacteria even though cultures of the CSF were sterile. In another 145 patients who did not have meningitis the results of the LA test were negative. The LA test, done as described in this article, is easier to perform than CIE and should be a useful addition to the diagnostic tests carried out on the CSF of any patient suspected of having meningitis.     

A SURVEY FOR 1,3,6,7-TETRAHYDROXY-C-GLYCOSYLXANTHONES EMPHASIZING THE “PRIMITIVE” LEPTOSPORANGIATE FERNS AND THEIR ALLIES

A survey for 1,3,6,7-tetrahydroxy-C-glycosylxanthones of representative species within the primitive vascular plants, emphasizing the leptosporangiate ferns, has indicated a limited distribution of these compounds within three leptosporangiate families: Hymenophyllaceae, Aspleniaceae and Marsileaceae. In the Hymenophyllaceae the distribution of these compounds appears to be a useful criterion for segregating species of Mecodium from other species of Hymenophyllum (sensu lato) and suggests that the tubulate vs. the valvate indusial condition may not be an ideal character for separating all species of Hymenophyllum (s.l.) from those of Trichomanes (s.l.). These compounds appear useful for delimiting several species of Elaphoglossum section Pachyglossa and support a relationship among the Aspleniaceae, Athyriaceae, and Elaphoglossaceae. Their presence in Marsilea also raises questions as to the origin of this group of plants.     

Pharmacologic identification of muscarinic receptors in the pylorus of the cat by binding of [3H]-quinuclidinyl benzilate

Muscarinic receptors in the smooth muscle of the cat pylorus (pyloric sphincter) were identified by binding of the ligand (±) [³H]-quinuclidinyl benzilate ([³H]-QNB). Receptor related binding of [³H]-QNB reached steady-state in thirty minutes at 37°C, was saturable, showed pharmacologic specificity and was stereoselective. An apparent equilibrium dissociation constant, K_D, of 1.9 ± 0.3 nM and maximum receptor concentration of 122 ± 13 femtomoles per mg of protein (means ± S.E.M.) were determined from Scatchard plots of [³H]-QNB binding. Hill coefficients of 0.99 and 1.01 indicated the absence of cooperative interactions. The muscarinic antagonists atropine and propantheline inhibited binding with IC₅₀ values in the nanomolar range, whereas bethanechol was over four orders of magnitude less potent. Noncholinergic agents had little or no effect on [³H]-QNB binding. The $\text{levo}$ isomer of QNB was about seventy times more effective at inhibiting binding than its $\text{dextro}$ isomer while $\text{dextro}$ benzetimide was greater than two thousand fold more active than $\text{levo}$ benzetimide. The isomers of another anticholinergic compound, tropicamide, also competed for [³H]-QNB binding sites in a stereoselective manner, the $\text{levo}$ isomer being eighty-five times more potent than the $\text{dextro}$ isomer.     

Seven furanoeremophilanes from three Senecio species

The investigation of two further Senecio species and the re-investigation of S. inaequidens afforded, in addition to known compounds, seven new furanoeremophilane derivatives. Six of these are closely related to cacalol, a sesquiterpene type which predominates in the species investigated.     

Iron mobilization from ferritin by chelating agents

The release of iron from horse spleen ferritin by the chelating agents desferrioxamine B, rhodotorulic acid, 2,3-dihydroxybenzoate, 2,2′-bipyridyl and pyridine-2-aldehyde-2-pyridyl hydrazone (Paphy) has been studied in vitro. Ferritin prepared by classical procedures involving thermal denaturation releases its iron less effectively than ferritin isolated by a modified procedure that avoids this step. Desferrioxamine B and rhodotorulic acid are the most effective in releasing iron from both preparations of ferritin. When FMN is added, iron release by desferrioxamine B, rhodotorulic acid, and 2,3-dihydroxybenzoate was effectively blocked, whereas both bipyridyl and Paphy showed a marked simulation. A substantial increase in iron release was also observed for bipyridyl and Paphy with ascorbate; a less important increase was noted for rhodotorulic acid. EDTA exerted a marked inhibition of iron release from ferritin with rhodotorulic acid, 2,3-dihydroxybenzoate, bipyridyl, and Paphy. The effects of citrate and oxalate on iron release by the chelators was small. The effect of the concentration of flavin on iron release from ferritin by bipyridyl and desferrioxamine B have been studied. Desferrioxamine is unable to mobilize FeII from ferritin following reduction by reduced FMN, whereas bipyridyl can rapidly complex the ferrous iron. The results are discussed in the context of our current concepts of storage iron mobilization in the treatment of iron overload.     

Hydration, thermoregulation, and performance effects of two sport drinks during soccer training sessions

In the present study, we aimed to compare the thermoregulatory response and soccer-specific training performance aspects of two commercially available sport drinks, both of similar carbohydrate concentration, but one containing 5.2% glycerol. Ten players participated in two similar outdoor training sessions and were randomly assigned to each of two drinks: a carbohydrate (C) beverage or a carbohydrate-glycerol (CG) beverage. Players consumed 500 mL of C or CG 30 minutes pre-exercise and at half-time. Pre- and postexercise body mass, core temperature (CT), and heart rate (HR) were recorded, and urine and blood samples were taken. No difference was observed between days for wet bulb globe temperature (session 1: 17.0 +/- 1.1 degrees C, session 2: 16.9 +/- 1.1 degrees C; P = 0.944). The degree of dehydration (% Delta BM) was greater after the C trial (P = 0.041). Similarly, percent change in plasma volume was greater in the C trial (P = 0.049). No overall main affect was observed between CT and mean exercise HRs during either training session (CT: P = 0.350; mean HR: P = 0.256), and there was no difference observed between groups in time to failure during the session-ending fatigue test (P = 0.547). Ingestion of a CG beverage provided players with better hydration than C alone. However, if training sessions are short (<75 minute), with adequate time for recovery, both drinks are sufficient for maintaining performance intensities during soccer-specific training.