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Comparison of propranolol and hydrochlorothiazide for thr initial treatment of hypertension. I. Results of short-term titration with emphasis on racial differences in response. Veterans Administration Cooperative Study Group on Antihypertensive agents.

We compared hydrochlorothiazide and propranolol hydrochloride for monotherapy of hypertension by a double-blind study of 683 men who were titrated to less than 90 mm Hg diastolic BP or to 640 mg of propranolol or 200 mg of hydrochlorothiazide. Propranolol reduced systolic BP from 146.0 +/- 14.4 (SD) to 134.8 +/- 16.3 mm Hg and diastolic BP from 101.6 +/- 4.6 to 90.5 +/- 7.5 mm Hg. Hydrochlorothiazide lowered both systolic BP more effectively from 146.5 +/- 15.8 to 128.8 +/- 12.2 mm Hg and diastolic BP from 101.3 +/- 4.5 to 89.4 +/- 6.5 mm Hg. In blacks, hydrochlorothiazide lowered systolic BP 20.3 +/- 14.3 mm Hg v 8.2 +/- 12.2 mm Hg for propranolol; hydrochlorothiazide reduced diastolic BP 13.0 +/- 7.0 mm Hg v 9.5 +/- 7.0 for propranolol. In whites, the systolic BP reductions were 15.3 +/- 12.0 mm Hg for hydrochlorothiazide v 13.2 +/- 13.1 mmn Hg for propranolol; diastolic BPs were 10.9 +/- 5.7 mm Hg for hydrochlorothiazide and 12.6 +/- 6.6 mm Hg for propranolol. In blacks treated with hydrochlorothiazide, 71.3% achieved diastolic BP of less than 90 mm Hg, v 53.5% with propranolol. There was no racial difference in dose response to propranolol, but blacks required much less hydrochlorothiazide to achieve control. We conclude that in this short-term study propranolol was as efficacious as hydrochlorothiazide in whites, but the latter was more effective than propranolol in blacks.

Adult↗

[Production and titration of a vaccine against the infectious encephalomyelitis of poultry].

A vaccine was produced against infectious encephalomyelitis of day-old chicks infected cerebrally with strain Calnek 1143. It is a brain suspension from killed birds that have shown disease symptoms, treated with penicillin and streptomycin and stored at -20 degrees C. Experiments were carried out to titrate the vaccine through determining the minimum infective dose for day-old chicks treated with 0.1 cm3 each of it, orally, as obtained from tenfold dilutions. It was found that birds do not manifest clinically the disease, however, with birds killed 20--25 days following infection there have been characteristic histologic changes speaking of infectious encephalomyelitis. The minimum infective dose of the various batches of vaccine have been found to range from 10(-3) to 10(-5)/cm3. Applied under the conditions of the practice the vaccine has proved harmless, contributing to eradication of the disease on the infected farms.

Animals↗

[Potentiometric titration in biological studies].

The employment of the potentiometric titration method for determination of the nature and concentration of ionized groups in synthetic polyelectrolytes, biopolymers and in membrane fragments of the cell has been considered. The interpretation of the results of potentiometric investigations in the biological system is complicated because of a neglection of the electrostatic factor and differentiation of molecular and supramolecular, structural changes affecting the availability of ionogenic groups. The method, however, provides an important information concerning the character and, particularly, the mechanisms of structural changes in biosystems and in their components under the influence of different factors.

Animals↗

Canine distemper virus titration in ferret peritoneal macrophages.

The sensitivity of a ferret peritoneal macrophage fluorescent antibody technique for assay of various strains of canine distemper virus was investigated. The macrophage system was compared with established methods of titration in canine kidney cell culture, Vero cell culture, and embryonated chicken eggs. It was found to be as sensitive as and in several instances more sensitive than the established methods.

Animals↗

Effects of thioridazine (Mellaril) on titrating delayed matching-to-sample performance of mentally retarded adults.

The effects of thioridazine on the performance of a titrating delayed matching-to-sample discrimination by four retarded adults was investigated. Trials began with the center of three response panels illuminated by one of three colors. The delay between depression of the center response panel and presentation of the two comparison stimuli on the side response panels varied according to the accuracy of the subjects' performance. The primary dependent variable was the limit of delay, defined as the longest delay at which the subject emitted four consecutive correct responses in a 30-minute session. The subjects' chronic doses of thioridazine were reduced systematically in a multiple baseline across-subjects design. For all of the subjects, the limit of delay increased after, and only after, reductions in the daily thioridazine dose had been implemented. Results indicated that the withdrawal of chronically administered thioridazine resulted in increased accuracy in a delayed matching-to-sample task, suggesting strongly that the drug impairs performance of this discrimination.

Adult↗

Comparative titration of Anaplasma marginale antibodies by card agglutination and complement-fixation tests.

The card agglutination test for anaplasmosis was improved so that bovine serum could be titrated for Anaplasma antibodies. The modified test was validated when its results on 1 set of serum samples were compared with the results furnished by the complement-fixation test on the same set. The samples tested were from cows inoculated with an Anaplasma vaccine or with either 1 of 2 virulent strains of Anaplasma marginale. A correlation coefficient of 0.60 was calculated between the values of the titers furnished by the 2 tests, and regression equations were calculated and used to estimate the serum titer in 1 test from a titer measured in the other. The results indicate that the simple card agglutination test can yield titers comparable with those of the complement-fixation test.

Agglutination Tests↗

[Detection of urinary organic acids by gradual titration of pH 2,0-7,4. Significance for the assessment of the litho-protective characteristic of the examined urine].

The role of organic acids in urine is not sufficiently known until today. From our detailed in vitro studies it can be concluded that some of them are highly efficacious in the inhibition of Ca-oxalate and Ca-phosphate crystal growth. Moreover, some of them showed, as acids and as salts, a strong lytic effect on stone-forming crystals and native stone-material. By the oral application to rats, concentrations preventing any precipitation out of meta- and instable Ca-oxalate solutions could be achieved. The renal excretion was controlled by the stepwise titration of preacidified urinary samples from pH 2.0 to 7.4 and the lithoprotective character of urine estimated by the Ca2+-binding capacity.

Animals↗

Titration of rat liver with digitonin: a well defined short term damage of cellular metabolism.

Carefully performed pulse titration of the isolated rat live in the course of continuous erythrocyte free perfusion with small amounts of digitonin causes a short term permeability of liver cell plasma membranes with concomitant short lived release of intracellular low or high molecular compounds such as ATP or lactate dehydrogenase. Gluconeogenesis from lactate being completely inhibited during this period restores within about one minute up to a level that depends on the amount of perfused digitonin. The described experimental model is suggested to be useful for the measurement of cytoplasmic metabolites under physiological conditions. It moreover offers the possibility to import foreign substances into liver cells that normally do not penetrate liver cell plasma membranes.

Adenosine Triphosphate↗

Intragastric titration of peptone-stimulated gastric acid secretion.

Fourteen male patients with duodenal ulcer were stimulated by a 10% peptone meal, and acid secretion was measured by continuous intragastric titration. The results were compared to the effects of intravenous infusion of pentagastrin given in a dose of 6.0 microgram/kg-hour on gastric acid secretion in the same 14 patients. Acid secretion reached the peak in the third 15-min period after peptone instillation and it was similar to that peak acid output/15 min produced by infusion of pentagastrin. Acid secretion in response to peptone in the second hour gradually diminished towards the basal level, on the contrary, during i.v. infusions of pentagastrin the acid secretion was well sustained. The acid response to peptone solution or pentagastrin infusion did not differ significantly in the first hour, but in the second hour the difference was significant. It is concluded that the gastric acid secretion induced by peptone is comparable to the effect of the highest dose of pentagastrin infusion only in the first hour. Reproducibility of gastric response to peptone and to pentagastrin infusion was very good (r = 0.79 and 0.87, respectively).

Adult↗

[Determination of the sulfate ion content in antibiotic sulfate salts by a complexometric titration method].

A possibility of assaying antibiotic sulfates, such as gentamicin, kanamycin, monomycin, neomycin, ristomycin, streptomycin, florimycin and polymyxin M sulfates for sulfate ions by titration with barium chloride in the presence of chlorphosphonaso-III, a metal indicator immediately in the salt solutions or after elimination of the cation by means of ion exchange (sulfocation exchange resins in H+-form) was tested. The procedure was shown to be adequate to the classical weight method.

Anti-Bacterial Agents↗

[A new protein titrator tape for self-assessment by outpatients with proteinuria].

ł- have invented a new dipstick (protein titrator tape) for measuring the volume of protein excreted in the 24-hour urine. The principle of the method is based on the protein error of indicators with the modification of a conventional dipstick test. The dipstick consists of two thick filter papers, containing differently adjusted pH indicators of tetrabromphenol blue, making it possible to detect a wide range of protein concentrations in the urine using a standard color chart that includes twenty color blocks. Two hundred and ninety outpatients had their urine samples assessed with this method as well as with the pyrogallol red test as a comparative study for quantitative measurement of protein concentrations. The new-type dipstick method exhibited good correlation with the results of the pyrogallol red test, especially in the range of protein concentrations from 50 mg/dl to 400 mg/dl, showing the linear equation of "y (Pyrogallol red) = 10.5 + 0.99 x (Dipstick) (r = 0.91, P < 0.01)". Although there was good correlation with the pyrogallol red test at higher concentrations from 400 mg/dl to 1,000 mg/dl, the dipstick method tended to exhibit lower concentrations than those indicated by the counterpart method. The rate of consistency between observers was quite high. This new-type dipstick method will offer a reliable method for patients or their family to assess their protein excretion in the urine every 24 hours at home using a portable urine sampling device.

Adult↗

[In vivo titration of tetanus antitoxins].

The theoretical background and the practical techniques of assay of tetanus antibodies on mice by the L+ toxine procedure, is precisely described in detail. Basing the arguments on certain aspects of the method, the accuracy of the test is estimated and its reproducibility is assessed, in terms of both in vivo and in vitro titrations.

Animals↗

Killed poliovirus antigen titration in humans.

To establish the antigen content of a killed poliovirus vaccine sufficiently potent to induce immunity with one or two doses and to establish a reference standard vaccine which has been tested under field conditions, a titration was carried out in infants to determine the amount of each of the three antigenic types of poliovirus vaccine required to induce seroconversion with a single dose. It has been observed that over a critical range of antigen concentration there is an essentially linear relationship between antibody response and quantity of antigen administered. More than 90 percent of the groups studied had detectable antibody after receiving single injections of 80, 8 and 64 D-antigen units of Types I, II and III, respectively. Four-fold less antigen for each of the three types was less effective. The implications of these findings for an efficient immunization procedure are discussed.

Antibodies, Viral↗

Intravenous nicardipine for the treatment of severe hypertension. A dose-titration infusion to therapeutic response.

Intravenous nicardipine titration, starting with 10 mg/hr and increased slowly every 4 minutes by the rate 1 mg/hr until target supine DBP of 90 mmHg was achieved, was a very effective and safe method for patients with very severe hypertension. All patients had their BP under good control with few adverse effects. Although the heart rate rose significantly there were only four cases with palpitation and one case with chest pain which spontaneously recovered without sequele.

Adult↗

Thermodynamic analysis of biotin binding to avidin. A high sensitivity titration calorimetric study.

Titration calorimetric studies on the binding of biotin to avidin were performed in phosphate buffered saline, pH 7.4. From the temperature dependence of the binding enthalpy (delta H), the delta Cp value was determined. While the delta H value of -23.4 kcal/mol at 25 degrees C is in close agreement with the previously determined value of -22.5 kcal/mol (Suurkusk, J. & Wadso, I. (1972) Eur. J. Biochem. 28, 438-441), the delta Cp value of -461 cal/mol biotin/K is significantly at variance with the value of -237 cal/mol biotin/K obtained in the previous study. A comparison of the thermodynamic data obtained for the avidin-biotin system with that of the streptavidin-biotin system revealed that the higher binding affinity of avidin for biotin is due to a smaller (negative) entropy of binding.

Animals↗

[Improving the laboratory diagnosis of rabies and titration of rabies viruses].

For primary isolation and titration of street strains of the rabies virus from brains of suspected animals, an assay prepared on the cell culture BHK-21/C 13 (rabies infection test - RTCIT) was used. The above assay proved to be reliable and its sensitivity proved to be comparable to the standard mouse inoculation test. Through this test, the results were obtained within 24 to 48 hrs on Lab-Tek tissue culture chamber/slides. It was found out that DEAE-dextran added to the cell culture only slightly increased the invasiveness of the virus in the samples tested. The method described herein is able to substitute the mouse inoculation test (MIT). In our laboratory, 20 vaccination strains of the rabies virus Vnukovo-32/107 and 25 street strains of the rabies virus (delivered from the field) - original fox brain suspensions. And 10 brain suspensions were negative when tested in laboratory conditions (by PMIF, RTCIT as well as by MIT methods).

Animals↗

[Experimentation with a new simplified proof of the classic Rantz and Randall technic and of an automatic titrator for rapid determination of the antitreptolysin titre].

One thousand human sera have been tested for O-streptolysin antibodies, using classic Rantz and Randall technic and a simplified proof, based upon a single initial serum dilution 1 : 200 and the determination of five titers, corresponding to 250-332-500-666-1000 antistreptolysin units/ml. The semplified proof has the advantage over the classic technic, to lower down to a half, routinary work. The use of Titrator Sclavo, greatly reduces the time involved in the performance of both tests.

Animals↗