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PubMed2001

[Small ovarian cysts in postmenopause: assessment of their malignant potential with vaginal ultrasonography and tumor marker Ca125 titration].

BACKGROUND: The aim of this study was to determine the risk of malignancy in cystic ovarian tumors < 10 cm in diameter in asymptomatic postmenopausal women. METHODS: All cystic ovarian tumors, detected by abdominal and transvaginal sonography screening, in asymptomatic postmenopausal women were evaluated with respect to size and morphology. Follow-up data were available both on patients undergoing surgery and on those who elected to be followed without operative intervention. Titration of the tumoral marker Ca125 was carried out, too. RESULTS: Unilocular cystic tumors were detected in 32 of 352 postmenopausal patients (9%), of 45-65 years of age arrived at the "Centre for diagnosis and therapy of menopausal diseases" of the III Divisione di Ginecologia e Ostetricia della Seconda Università degli Studi di Napoli from the 1st January to the 31st December 1999. All tumors were < 10 cm in diameter and 98% were < 5 cm in diameter; just one tumor was hardly > 5 cm in diameter (5.8), 14 of these cystic ovarian tumors (49%) resolved spontaneously within 60 days while 18 (51%) persisted. Seven patients with persistent cystic ovarian tumors underwent operative tumor removal. Five of these patients had serous cystadenoma and 2 other women had cystoadenofibroma. Not even one case of ovarian carcinoma was found in this group. The remaining 11 patients with unilocular cystic ovarian tumors underwent sonography control every 3 months for one year and no one of these patients developed ovarian carcinoma. In all these patients the dosage of the tumoral marker Ca125 remained under the suspicious threshold of malignant ovaric tumor (Ca125 = 35 U/ml). CONCLUSIONS: Unilocular cystic ovarian tumors < 5 cm in diameter in asymptomatic postmenopausal women were associated with minimal risk for ovarian cancer. In contrast, complex ovarian cysts wall abnormalities or solid areas are associated with a significant risk for malignancy. These date are important in determining therapeutic optimal strategies in these patients.

Aged↗

PubMed1975

Titration of a brucella protein allergen in sheep sensitized with Brucella melitensis.

A protein allergen extracted from a rough strain of B. melitensis was titrated in sheep sensitized by vaccination with the attenuated B. melitensis strain Rev. I. Single doses of allergen were given per animal by the intradermal or palpebral routes. Doses over a 100-fold range produced delayed hypersensitivity reactions of similar magnitude by both routes. The most suitable method for application in the field was a dose of 50 mug given by the palpebral route (0.5 ml subcutaneously in the upper eyelid) with readings taken 48 hours after inoculation. Sheep vaccinated with H 38 adjuvant vaccine for 6 to 9 months showed positive reaction to the allergic test, whereas non-vaccinated non-infected sheep showed no reactions. No increase in agglutinations titers following allergic test was observed in either Rev. I or H 38 vaccinated sheep.

Allergens↗

PubMed1975

Isobaric titration of readine monolayers: kinetics of hydrolysis of glycerides by pancreatic lipase B.

The rate of lipolytic enzyme-catalyzed reactions yielding water-soluble products can be measured by isobaric titration. The method is based upon the measurement of the amount of substrate that must be added to a monalayer to maintain constant surface pressure during the course of the enzymatic reaction. The rate constants determined for the hydrolysis of trioctanion and 1,2-diotanoin by pancreatic lipase were identical with those determined by the variable surface pressure method and by a radioactive substrate technique. This direct titrimetric method has a wider dynamic range and more versatility for following surface reactions that previously described systems.

Animals↗

PubMed1975

An inexpensive device for sample stirring in VSU Zeiss spectrophotometers. Its use for kinetic measurements and active site titrations with immobilized enzymes.

The construction of a simple and effective sample stirring device for commercial spectrophotometers and its use for continuous kinetic measurements and active site titrations with immobilized enzymes is described. Sepharose-bound leucine aminopeptidase and trypsin were selected as model enzymes to test the performance of the magnetic stirring equipment. Kinetic parameters of insolubilized leucine aminopeptidase using L-leucine p-nitroanilide as substrate and the catalytic site concentration of matris-bound trypsin using p-nitrophenyl p'-guanidinobenzoate as active site titrant could be evaluated without significant interference from the turbidity of the stirred Sepharose suspension. The problem of grinding of the support material could be overcome. Both unbound native and carrier-fixed enzyme may be reacted under identical conditions with similar convenience and sensitivity.

Animals↗

PubMed2002

Iodine--iodide reference electrode for potentiometric titrations of bases in acetic acid.

The suitability of the half-cell Pt/I2, KI in glacial acetic acid as reference electrode for potentiometric titrations of weak bases in the same medium was investigated. This electrode is easily prepared. It has been found very convenient in use and performing at least as well as the best electrodes used for the same purpose. Some phenomenological aspects of the behaviour of the above half-cell, of interest for the use as the reference electrode in the laboratory practice have been observed, that show important differences respect aqueous medium and other organic solvents.

Acetic Acid↗

PubMed2002

[Comparative titration of three antivenin serums used against sub-Saharan African snakes].

The standardisation of serotherapy is necessary in Africa mainly because of the frequency of envenomations and the lack of alternative treatments. Comparative titrations of FAV-Afrique (Aventis Pasteur), Polyvalent serum (Serum Institute of India = SII) and Polyvalent antivenin (South African Vaccine Fabricants Ltd = SAIMR) were carried out on venoms of Echis ocellatus from Cameroun, E. ocellatus from Mali, E. leucogaster and Naja melanoleuca. The 50% protective doses (ED50) of the antivenoms were given according either to i) the in vitro method which consists of inoculating 5 batches of 5 mice with a mixture containing 3 DL50 of venom and increasing volumes of antivenom incubated for 30 mn at 37 degrees C and ii) the in vivo method which consists of successive administration of venom and then antivenom after a 30 to 60 mn interval. The three antivenoms showed a similar efficacy against all the Echis venoms. Interestingly, the SAIMR proved to be effective against the venom of E. leucogaster and E. ocellatus although no venom of Echis was used to immunise horses during the preparation of antivenom. Conversely, this paraspecificity did not exist with the Naja melanoleuca venom against which FAV Afrique showed a higher efficacy. The electrophoresis pattern of FAV-Afrique performed on acetate gel strips showed only one protein fraction (76 g.l-1), whereas both the SII and SAIMR antivenoms showed four fractions whose protein concentrations was respectively 64 g.l-1 and 145 g.l-1.

Africa South of the Sahara↗

PubMed2002

Titration of KATP channel expression in mammalian cells utilizing recombinant baculovirus transduction.

A variety of transfection approaches have been used to deliver plasmids encoding ion channel genes into cells. We have used the baculovirus transduction system, BacMam, to demonstrate transient expression of multi-subunit KATP channels in CHO-K1 and HEK-293 EBNA cells using sulfonylurea receptor 1 (SUR), SUR2A, SUR2B, and KIR 6.2 genes. [3H]-glyburide binding, patch clamp, and DiBAC4(3) measurements of membrane potential changes were used to monitor channel expression. BacMam delivery of each SUR isoform with KIR6.2 was demonstrated based on its pharmacological profiles. Expression levels of SUR1 and KIR6.2 were titrated by varying the viral concentration or time of virus addition, with functional activity measured in as little as 4-6 hours posttransduction. Further increases in BacMam virus induced sufficient KATP expression to dominate membrane potential without pharmacological opening of the channel. Independently altering treatment with virus containing either the SUR1 or KIR6.2 gene revealed interactions among subunits during formation of functional channels in the plasma membrane. This study demonstrates the utility and versatility of BacMam as a valuable gene delivery tool for the study of ion channel function.

ATP-Binding Cassette Transporters↗

PubMedDate not supplied

Potentiometric/turbidometric titration of antiperspirant actives.

A titration procedure that simultaneously monitors the pH and turbidity of an antiperspirant solution during neutralization with sodium hydroxide was developed to characterize antiperspirant actives. Aluminum chloride, aluminum chlorohydrate (ACH), and aluminum zirconium glycine complex (AZG) gave distinctive pH/turbidity profiles. The activated forms of aluminum chlorohydrate (ACH') and aluminum zirconium glycine complex (AZG') produced more turbidity than the non-activated forms. On an equimolar basis, AZG' produced more turbidity than any of the antiperspirant actives tested.

Deodorants↗

PubMed1975

Antiglobulin test for titration of antilymphocyte globulin.

An antiglobulin assay, derived from the indirect Coombs' reaction has been adapted to the titration of antilymphocyte globulin (ALG). Ten different ALG preparations have been investigated by this test and titres obtained are satisfactorily correlated with skin allograft survival in monkeys, rosette inhibition and mixed lymphocyte reaction inhibition. The antiglobulin test has also proved to be valuable for the monitoring of ALG-therapy in patients as well as for studying the mode of action of this potent immunosuppressive agent.

Agglutination Tests↗

PubMed1961

Antistreptolysin-O: its interaction with streptolysin-O, its titration and a comparison of some standard preparations.

The quantitative determination of antistreptolysin-O in the serum of a patient is frequently used as an aid in the presumptive diagnosis of a recent streptococcal infection. Difficulties have been experienced in obtaining consistently reproducible results, when large numbers of sera are tested, with accurate titration methods simple enough to be used routinely in a serological laboratory.An investigation of the streptolysin-antistreptolysin reaction has revealed that the time of interaction at 37 degrees C routinely in use in this test is very critical. Results are presented suggesting that this critical effect is due to the instability of the toxin, which is possibly attacked by the active proteinase present in streptolysin preparations. It was possible to develop a modified method using twofold dilutions of serum and a 50% haemolysis endpoint under conditions where proteinase has little effect on the toxin. This method has proved satisfactory in routine laboratory use with large numbers of sera.A quantitative comparison of various standard antistreptolysin preparations available throughout the world revealed a reasonable constancy of absolute value when compared with the original Todd standard. Differences in their neutralization reactions with streptolysin-O were, however, apparent.

Antistreptolysin↗

PubMed1992

Urinary salt titrator stick: a useful and quick estimate of dietary sodium intake?

Repeated measures of urinary salt excretion are the best compromise between reliability and convenience for estimating dietary salt intake. In order to assess the accuracy of the Uropaper urinary salt titrator stick (giving discrete readings of 4, 6, 8, 10, 12 or 14 g/l of NaCl), 312 urine samples were analysed both with the stick and with an ion-selective electrode. There was a good stick-electrode correlation in all the 312 samples (r = 0.84). With a tolerance of +/- 1 g/l, the percentages of correct estimations dropped from 82% to 33% with increasing concentrations of NaCl in the urinary sample. For NaCl concentrations greater than 8 g/l (137 mmol/l) the error in the stick measurement consisted almost exclusively of overestimation of the electrode readings. These results were unaffected by the concentration of urinary potassium. No discrepancies were found among three different readers. This stick is easy to use and measures, with reasonable accuracy, low urinary NaCl concentrations. It could be useful for self-monitoring during low NaCl diets.

Administration, Oral↗

PubMed2004

A comparison of skin endpoint titration and skin-prick testing in the diagnosis of allergic rhinitis.

Among the many methods of allergy diagnosis are intradermal testing (IDT) and skin-prick testing (SPT). The usefulness of IDT has been called into question by some authors, while others believe that studies demonstrating that SPT was superior might have been subject to bias. We conducted a study to compare the validity of SPT and IDT--specifically, the skin endpoint titration (SET) type of IDT--in diagnosing allergic rhinitis. We performed nasal provocation testing on 62 patients to establish an unbiased screening criterion for study entry. Acoustic rhinometric measurements of the nasal responses revealed that 34 patients tested positive and 28 negative. All patients were subsequently tested by SET and SPT. We found that SPT was more sensitive (85.3 vs 79.4%) and more specific (78.6 vs 67.9%) than SET as a screening procedure. The positive predictive value of SPT was greater than that of SET (82.9 vs 75.0%), as was the negative predictive value (81.5 vs 73.0%). None of these differences was statistically significant; because of the relatively small sample size, our study was powered to show only equivalency. The results of our study suggest that the information obtained by the SET method of IDT is comparable to that obtained by SPT in terms of sensitivity, specificity, and overall performance and that both SET and SPT correlate well with nasal provocation testing for ragweed. Therefore, the decision as to which to use can be based on other factors, such as the practitioner's training, the desire for quantitative results, the desire for rapid results, and the type of treatment (i.e., immunotherapy or pharmacotherapy) that is likely to be chosen on the basis of test results.

Adult↗

PubMed1997

Comparison of hemagglutination and solid phase titration methods for determination of critical prenatal antibody titers.

The hemagglutination (HA) tube method is the standard method for determination of antibody titer in prenatal samples. Most facilities use a titer between 8 and 32 as their definition of a critical value when amniocentesis may be considered. This study determined if there is a relationship between the results of HA tube and solid phase (SP) titers performed on the same sample. Forty-six paired samples containing known antibody were titrated by both HA tube and SP methods and the results subjected to data analysis. We conclude that there is a strong correlation between HA tube and SP methods in titer end points; i.e., SP was greater than or equal to HA in every case. In addition, the appropriate critical SP titer is 64, which is at least equivalent to an HA critical titer of 16.

Journal Article↗

PubMed2005

Coulometric titration of ketotifen in tablets.

A method for the determination of ketotifen involving its reaction with iodine in an alkaline medium is presented. In coulometric titration using biamperometric end-point detection 0.25-2 micromol (77-618 microg) of ketotifen was successfully determined. The elaborated method was applied to the determination of ketotifen in drugs.

Algorithms↗

PubMed1999

[The hydrogen bond between 5-(2-carboxyphenyl)-10, 15, 20-triphenylporphyrin and amino acid ester--study with UV-Vis titration and 1H-NMR].

The hydrogen bonds between the hydrogen of pyrrols in 5-(2-carboxyphenyl)-10,15,20-triphenylporphyrin and the oxygen of the carboxyl group of amino acid ester were confirmed by UV-Vis spectroscopic titration method and 1H-NMR. When amino acid ester was added to o-TPPCO2H solution in CHCl3, the Soret and Q and red-shifted dramatically and several isobestic points could be observed in UV-Vis spectra. In 1H-NMR, the signal of the hydrogen atoms of pyrrole in o-TPPCO2H (-2.78 ppm) decreased and a new signal in 0.260 ppm emerged, when o-TPPCO2H mixed with L-PheOEt at 1 : 1 (mol/mol).

Amino Acids↗

PubMed2005

Problems in the interpretation of nonaqueous titrations.

Most phenomena (like promoting and leveling as well as differentiating effects) of common nonaqueous titrations can be explained by the Brönsted's concept combined with the hydrogen bond theory but some open problems are shown in connection with the use of formic acid and/or acetic anhydride.

Acetic Anhydrides↗

PubMed2005

Characterisation of high-rate acidogenesis processes using a titration and off-gas analysis sensor.

The characteristics of the glucose degradation by acidogenesis processes were investigated both in a long-term operating laboratory-scale continuously stirred tank reactor and in short-term experiments utilising a titration and off-gas analysis (TOGA) sensor. The results obtained from continuous-flow experiments in both reactors demonstrated that the TOGA sensor can be applied as a useful tool for the study of acidogenesis processes under steady-state and dynamic conditions. No significant effect from the culture transfer could be detected in the study with the TOGA sensor. Furthermore, the variation of gas production rate could be monitored at real time by the TOGA sensor. The experiments showed that the distribution of acidogenic products in the liquid and the gas phase was significantly influenced by the hydraulic retention time at least in the short term.

Bacteria, Anaerobic↗

PubMed2005

Anhydrous formic acid and acetic anhydride as solvent or additive in nonaqueous titrations.

The use and importance of formic acid and acetic anhydride (Ac2O) is increasing in nonaqueous acid-base titrations, but their interaction with the solutes is poorly understood. This paper attempts to clarify the effect of the solvents; NMR and spectrophotometric investigations were done to reveal the interactions between some bases and the mentioned solvents. Anhydrous formic acid is a typical protogenic solvent but both the relative permittivity and acidity are higher than those of acetic acid (mostly used in assays of bases). These differences originate from the different chemical structures: liquid acetic acid contains basically cyclic dimers while formic acid forms linear associates. Ac2O is obviously not an acidic but an aprotic (very slightly protophilic) solvent, which supposedly dissociates slightly into acetyl (CH3CO+) and acetate (AcO-) ions. In fact, some bases react with Ac2O forming an associate: the Ac+ group is bound to the delta- charged atom of the reactant while AcO- is associated with the delta+ group at appropriate distance.

Acetic Anhydrides↗