ACTION OF DIETHYLSTILBOESTROL ON MOUSE VAGINAL SIALIC ACIDS (I)

1969 ◽  
Vol 62 (4) ◽  
pp. 657-662 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Acid Concentration ◽  
Dose Response ◽  
Response Curve ◽  
Sialic Acids ◽  
Mucous Cells ◽  
Total Sialic Acid ◽  
Close Relationship ◽  
Dose Dependent

ABSTRACT Diethylstilboestrol administered in lower doses than necessary to induce full vaginal cornification in spayed mice, resulted in vaginal mucification. The thickness of the layer of mucous cells was found to be dose dependent; it was low in the controls, reached a maximum at a dose of 0.02 μg, but full cornification and absence of mucification was present at 0.05 μg. Sialic acid was present in the mucoproteins, and determination of the total amount of sialic acid per vagina showed a close relationship to the histologically evaluated degree of mucification. The ratio between total sialic acid per vagina and vaginal weight (»sialic acid concentration«) gave a dose response curve with a λ value of −0.061. The possibility of using this parameter for oestrogen assay is discussed.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

Immunoassay of low concentrations of albumin in urine by latex particle counting.

1988 ◽  
Vol 34 (2) ◽  
pp. 416-418 ◽  
Author(s):  
C L Cambiaso ◽  
D Collet-Cassart ◽  
M Lievens
Keyword(s):  
Detection Limit ◽  
Dose Response ◽  
Response Curve ◽  
Latex Particle ◽  
Urinary Albumin ◽  
Diagnostic Systems ◽  
Particle Counting ◽  
Low Concentrations ◽  
The Impact

Abstract We describe here a nonisotopic immunoassay, based on particle-counting technology, for the determination of urinary albumin. The assay takes only 35 min and has been fully automated on the IMPACT (Acade Diagnostic Systems, Brussels, Belgium) machine. The system measures albumin within a linear range between 6.25 and 50 mg/L and has a detection limit of 0.4 mg/L. Analytical recoveries at three concentrations ranged between 96% and 102%. Within-run precision ranged from 1.6% to 9.5%. The method was compared with a commercial nephelometric immunoassay system and a correlation coefficient of 0.996 was found for 216 urine samples. No antigen excess affects the shape of the curve in our system, whereas in nephelometry a 3 g/L solution of albumin starts to decrease the dose-response curve.

CHANGES IN PLATELET SURVIVAL AND SIALIC ACID CONCENTRATION IN PLASMODIUM BERGEI INFECTED RATS

1987 ◽  
Author(s):  
E M Essien ◽  
A L Inyang
Keyword(s):  
Sialic Acid ◽  
Acid Concentration ◽  
Wistar Rats ◽  
Severe Thrombocytopenia ◽  
Control Value ◽  
Total Sialic Acid ◽  
Platelet Survival ◽  
Immune Mediated ◽  
The Difference ◽  
Survival Studies

Reduced circulating platelet count sometimes to thrombocytopenic levels in man and normally severe thrombocytopenia in animals are well known features of acute Plasmodium falciparum or experimental P. bergei infections in these respective organisms. Suggested mechanism(s), disseminated intravascular coagulation or immune mediated mechanism, thought to be involved in these observations are disputed. Shortened platelet survival has been reported in man.We now present data on platelet survival and total platelet sialic acid concentration in P. bergei-infected Wistar rats. A total of 52 rats were used. For the platelet survival studies each of the 8 suckling test animals was infected by intraperi-toneal route with mouse-passaged P. bergei 4-5 days before inaction of Cr-labelled homologous rat platelets (50 μCi Na51 CrC4/rat) the platelets being obtained from adult Wistarrats. Blood samples were then collected 2 hr after the injection (zero hr sample) and subsequently at 17.0, 42.5 and 66 hr s.Platelet recovery and survival curves were determined on these samples. It was found dat fewer platelets (as % recovery) were obtained from each infected rat sample compared with control, the difference was significant in the 42.5 and 66 hr samples: 7.9 ± 8.1 (test) vs 41.4 ± 15.2% (C) for 42.5 hr and 2.8 ±4.1 (t) vs 26.8 ± 6.2% (C) for the 66 hr samples (p < 0.005 for each). For sialic acid determinations, 40 suckling Wistar rats (30 test, 10 control) were treated as for survival studies.At identical periods, blood was collected, washed platelets obtained, lysed and protein and total sialic acid determined by Lowry (1951) and Aminoff (1961) methods respectively. Total sialic acid of 7.02 ± 4.21 nM/mg protein at 42.5 hrs and 4.8 ± 2.14 at 66 hrs were significantly less than control value of 11.43 nm/mg protein and also showed a negative correlation (r = -0.95) with % parasitaemia.It is concluded that P. bergei infection causes a reduction in total platelet sialic acid with resultant significant shortening of the platelet life span.

scholarly journals Differential proliferative responses of cultured Schwann cells to axolemma- and myelin-enriched fractions. I. Biochemical studies.

1984 ◽  
Vol 99 (6) ◽  
pp. 2309-2313 ◽  
Author(s):  
J E Yoshino ◽  
M P Dinneen ◽  
B L Lewis ◽  
J H Meador-Woodruff ◽  
G H Devries
Keyword(s):  
Schwann Cells ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Hill Coefficient ◽  
Maximal Response ◽  
Response Curves ◽  
Cultured Schwann Cells ◽  
Rat Brainstem ◽  
Dose Dependent

Cultured rat Schwann cells were treated for 72 h with axolemma- and myelin-enriched fractions prepared from rat brainstem. [3H]Thymidine was added to the cultures 48 h before the termination of the experiment. Although, both fractions produced a dose-dependent uptake of label into Schwann cells, the shape of the dose response curves and rates at which [3H]thymidine was incorporated were different. The axolemma-enriched fraction produced a sigmoid dose response curve with a Hill coefficient of 2.05. The dose response curve for myelin rose sharply and saturated at a level that was approximately 50% of the maximal response observed with axolemma. Schwann cells that had been treated with axolemma exhibited little change in the rate of [3H]thymidine incorporation from 36-72 h after the addition of the membranes. In contrast, Schwann cells accumulated label three times faster during the 48-72-h period following the addition of myelin to the cultures when compared with the rate during the preceding 12-h interval. Furthermore, the mitogenic activity of the myelin-enriched fraction was decreased by the addition of ammonium chloride, a lysosomal inhibitor, whereas the activity of the axolemmal fraction was not impaired.

Reversible and irreversible interactions of DIDS with the human electrogenic Na/HCO3 cotransporter NBCe1-A: role of lysines in the KKMIK motif of TM5

2007 ◽  
Vol 292 (5) ◽  
pp. C1787-C1798 ◽  
Author(s):  
Jing Lu ◽  
Walter F. Boron
Keyword(s):  
Voltage Clamp ◽  
Dose Response ◽  
Response Curve ◽  
Xenopus Oocytes ◽  
Transmembrane Segment ◽  
Initial Value ◽  
Irreversible Inhibition ◽  
Electrode Voltage

Others have shown that H2DIDS reversibly and covalently binds to the first lysine (K) in the SKLIK motif at the extracellular end of transmembrane segment 5 of the Cl-HCO3 exchanger AE1. Here we mutated K558, K559, and/or K562 in the homologous KKMIK motif of human NBCe1-A. We expressed constructs in Xenopus oocytes, and used a two-electrode voltage clamp to test the sensitivity of the NBC current (−160 to +20 mV) to DIDS. A 30-s DIDS exposure decreased the current at 0 mV, and a subsequent albumin wash returned the current to the initial value (less any irreversible DIDS inhibition), permitting the determination of a complete dose-response curve on a single oocyte. For all constructs, the reversible DIDS inhibition of the NBC current decreased at more negative voltages. The apparent inhibitory constant for reversible DIDS binding increased in the sequence RRMIR < KKMIK ( wt, ∼40 μM) < NKMIK ≅ NKMIN ≅ KKMIN < KNMIN ≅ KNMIK < NNMIK < NNMIN (∼400 μM) < DDMID < EEMIE (∼800 μM). Thus the second K is the most important for reversible DIDS blockade. Nevertheless, these mutations had relatively little effect on slope conductance in the absence of DIDS. For KKMIK, RRMIR, NKMIK, KKMIN, KNMIK, and NNMIN, the rates of irreversible inhibition by DIDS roughly parallel the apparent affinities for reversible DIDS binding. The rate was extremely low for DDMID. The fitted maximal inhibitions were 80–91% for the first five constructs, and 66% for NNMIN. Thus DIDS probably reversibly binds before irreversibly reacting with NBCe1-A. Finally, tenidap blocks not only KKMIK, but also NNMIN and EEMIE.

scholarly journals SIALIC ACIDS ON THE PLASMA MEMBRANE OF CULTURED HUMAN LYMPHOID CELLS

1972 ◽  
Vol 53 (2) ◽  
pp. 466-473 ◽  
Author(s):  
Steven A. Rosenberg ◽  
Albert B. Einstein
Keyword(s):  
Cell Cycle ◽  
Sialic Acid ◽  
Sialic Acids ◽  
Lymphoid Cells ◽  
Limited Time ◽  
Total Sialic Acid ◽  
Human Lymphoid Cell ◽  
G2 Phase ◽  
Lymphoid Cell Lines ◽  
Synchronized Cultures

From 61 to 92% of the total sialic acid of a variety of human lymphoid cell lines maintained in tissue culture is present on the cell surface as measured by its susceptibility to cleavage by Clostridium perfringens neuraminidase. These cells contain from 1.22 x 108 to 6.99 x 108 molecules of surface sialic acid per cell. In synchronized cultures synthesis of surface sialic acid occurs only during a limited time in the late G2 phase of the cell cycle. The amount and density of surface sialic acid vary considerably throughout the cell cycle.

scholarly journals Development of a feed-intake model for evaluation of toxins associated with endophyte-infected fescue

2007 ◽  
Vol 13 ◽  
pp. 403-405
Author(s):  
P.A. Eichen ◽  
S.L. Raney ◽  
G.E. Rottinghaus ◽  
D.E. Spiers
Keyword(s):  
Dose Response ◽  
Feed Intake ◽  
Response Curve ◽  
Fescue Toxicosis ◽  
Small Reduction ◽  
Future Studies ◽  
Specific Effects ◽  
Keywords Rat ◽  
Reliable Model ◽  
Dose Dependent

Feed intake of rats may serve as a sensitive respondent to toxins found in endophyte-infected fescue. Unfortunately, there have been few controlled studies of feed intake to create a reliable model. In the present study, rats were fed diets containing different amounts of endophyte-infected fescue (E+) and ergovaline (EV; a primary toxin associated with fescue toxicosis) to develop a dose-response curve for feed intake. Dose-dependent reduction in feed intake was observed, with a decrease even at the lowest concentration of EV. Involvement of ergotamine (i.e. another toxin in E+) in fescue toxicosis-induced reduction in intake was evaluated by adding it to diets. In contrast to EV treatment, there was only a small reduction in feed intake with ergotamine, followed by rapid recovery to pretreatment levels. A more effective paradigm for evaluating the effect of different toxins on feed intake and potential treatments may be a restricted feed regimen. Rats placed on a 2-h restricted-feed program of ground commercial chow followed by E+ diet show a decrease in both feed intake and growth. Future studies will refine this routine to identify specific effects of toxins found in endophyte-infected fescue on feed intake. Keywords: rat, fescue toxicosis, feed intake

Evaluation of cinnamamide as an avian repellent: Determination of a dose-response curve

1995 ◽  
Vol 44 (4) ◽  
pp. 335-340 ◽  
Author(s):  
Richard W. Watkins ◽  
Elaine L. Gill ◽  
Julie D. Bishop
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve

Advances in and Limitations of Up-and-down Methodology

2007 ◽  
Vol 107 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Nathan L. Pace ◽  
Mario P. Stylianou ◽  
David C. Warltier
Keyword(s):  
Statistical Methods ◽  
Dose Response ◽  
Response Curve ◽  
Dose Response Curve ◽  
Binary Response ◽  
Target Dose ◽  
Anesthesia Research ◽  
Tolerance Distribution ◽  
Probability Of Response

Abstract Sequential design methods for binary response variables exist for determination of the concentration or dose associated with the 50% point along the dose–response curve; the up-and-down method of Dixon and Mood is now commonly used in anesthesia research. There have been important developments in statistical methods that (1) allow the design of experiments for the measurement of the response at any point (quantile) along the dose–response curve, (2) demonstrate the risk of certain statistical methods commonly used in literature reports, (3) allow the estimation of the concentration or dose—the target dose—associated with the chosen quantile without the assumption of the symmetry of the tolerance distribution, and (4) set bounds on the probability of response at this target dose. This article details these developments, briefly surveys current use of the up-and-down method in anesthesia research, reanalyzes published reports using the up-and-down method for the study of the epidural relief of pain during labor, and discusses appropriate inferences from up-and-down method studies.

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