Terms Of International Units Research Articles

Molecular diagnosis of Cytomegalovirus infection: clinical performance of the Aptima transcription-mediated amplification assay toward conventional qPCR chemistry on whole blood samples.

In this paper, we describe the clinical performance of a novel transcription-mediated amplification (TMA) assay for the detection and quantification of human Cytomegalovirus (HCMV) DNA from whole blood samples. This is a pivotal analysis in immunocompromised patients [transplanted, HIV-positive, and Hematopoietic Stem Cell (HSC) recipients], and molecular tests with high sensitivity and specificity are necessary to evaluate the HCMV viral load in these patients. To our knowledge, this is the first in-depth evaluation of TMA chemistry for HCMV diagnosis on whole blood samples. Moreover, also technical aspects of this assay make it suitable for clinical diagnostics.

A study of reported factor IX use around the world

Replacement therapy has significantly improved the life expectancy and lifestyle of people with haemophilia. The objectives of this article were to study the reported factor IX (FIX) use on a country-by-country basis and address the following question: Does the reported FIX use vary by national economies? We obtained data on the reported number of international units (IUs) of FIX used for 90 countries from the Marketing Research Bureau and the World Federation of Hemophilia. Results show that the reported FIX use varies considerably across national economies, even among the wealthiest of countries.Trends suggest that the reported FIX usage increases with increasing economic capacity and has been increasing over time. Trends also suggest that consumption of FIX has been increasing at a greater rate in high income countries. Given these trends, there will likely be an overall increase in the amount of FIX concentrates used in the treatment of haemophilia B. We also found that FIX use both in terms of IUs per capita and IUs per person provide a complete picture of the level of haemophilia care within a country. Such information is critical for planning efforts of national healthcare agencies to determine realistic budget priorities and pharmaceutical manufacturers to determine adequate production levels of FIX concentrates. By improving the data collection and surveillance of FIX use for the treatment of people with haemophilia B, we can identify trends and needs of patients and highlight best treatment practices among countries.

Bacillus thuringiensis—product standardisation

At present, all accepted methods for standardisation are based on bioassay against living insects. These methods are slow, expensive and require a large number of ‘standard’ insects. Potency is expressed in terms of International Units per gram or per milligram. However, it must be recognised that there is only one International Standard and the standardised applies only to Trichoplusia ni as the target. Many other methods have been described but none are acceptable. Bt producing companies are at present attempting to come to agreement over standards and procedures to be used in the future.

Standardization of Serum Ceruloplasmin Concentrations in International Enzyme Units with o-Dianisidine Dihydrochloride as Substrate

Abstract We describe a method for calculating the absorptivity (in terms of substrate consumed) of the colored solution obtained when o-dianisidine dihydrochloride is oxidized by ceruloplasmin. By oxidizing o-dianisidine dihydrochloride with known amounts of hydrogen peroxide we could determine that the molar reacting ratio of o-dianisidine to hydrogen peroxide is 2:1. So calculated, absorptivity is 9.6 ml µmol-1 cm-1, the figure used to estimate ceruloplasmin oxidase activity in terms of International Units.

Antibody Response to a Human Diploid Cell Rabies Vaccine

An experimentally killed rabies virus vaccine prepared in a human diploid cell strain (WI-38)-Wyeth rabies vaccine (WRV)-was used by various injection schedules in two separate studies to define more closely in human volunteer subjects an effective vaccination schedule for pre- or postexposure immunization, particularly for donors of rabies-hyperimmune plasma. To permit valid comparisons between our results and those of other workers, antibody levels achieved were expressed in terms of international units (IU) per milliliter of serum. Antibody response of previously nonvaccinated persons were only modest after a single dose of WRV, never reaching a level higher than 0.80 IU/ml over a 56-day testing period. Moreover, antibody was not detected at 0.16 IU/ml before the 14th day, either after a single dose or after two doses given 3 days apart. The best response followed four doses of WRV given within 4 weeks. This schedule resulted in the highest rate of seroconversion to the >/=6 IU/ml antibody level required of potential rabies-immune plasma donors. Giving the first vaccine dose in aluminum hydroxide diluent did not enhance the antibody response. There was a definite suggestion in the various injection schedules that higher and more sustained antibody levels were reached when the interval between the first and second vaccine doses was longest. The greater immunogenicity of WRV as compared with duck embryo vaccine was best demonstrated by the fact that a single booster dose of duck embryo vaccine to previously vaccinated individuals resulted in only a sevenfold antibody rise during the following 56 days, whereas a booster dose of WRV elicited a 69-fold rise. Al(OH)(3) in the first dose of WRV had no effect, but the enhancing effect of a longer interval between vaccine doses was noted once again; 20 of 20 subjects who received three doses of WRV with 4 weeks between doses developed good levels of rabies antibody, and 19 exceeded 6 IU/ml.

Immunochemical analysis of parasporal crystal digests of Bacillus thuringiensis as an index of insecticidal activity

An immunoelectrophoretic method is described for analyzing alkali parasporal crystal digests of Bacillus thuringiensis preparations (Dipel TM). There were two distinct immunoprecipitate peaks (A and B) in the direction of the anode. The higher A peak had no correlation with the bioactivity of B. thuringiensis samples, whereas, the height of the B peak was directly proportional to the bioactivity. There was excellent agreement between the immunoassay and the bioassay of insecticidal potency in terms of international units.

Urinary prolactin excretion in man.

PROLACTIN was the first pituitary hormone to be prepared in crystalline form (1), and various methods have been successfully used to extract it from pituitary tissue and to assay the material thus obtained. However, with one exception (2), no assay of prolactin excreted in human urine in terms of international units has been reported. The purpose of this paper is to present a method of extraction and assay of prolactin excreted in human urine, together with some of the results of assays in patients. Extraction procedure 1. Precipitation: To a 24-hour urine specimen, refrigerated during collection, are added 1 per cent by weight of sodium chloride and four volumes of 96 per cent ethyl alcohol. If the urine is not acid, it is acidified to litmus with acetic acid before addition of the alcohol. The precipitate is allowed to settle over night in the refrigerator, and collected by decantation and centrifugation. The precipitate is washed twice with 96 per cent alcohol, twice with ether, and dried. 2. Dialysis:...

Chorionic gonadotropin in the blood and urine during early pregnancy

Since the development and use of biologic tests for pregnancy, there has been a considerable accumulation of uncoordinated data recording the time of appearance of chorionic gonadotropin in the urine and serum of women after fertilization. The appearance of this hormone has been variously recorded at “a few days after implantation of the ovum”4, 13 to “two weeks after the expected but missed menstrual period.”3, 5, 14, 23 Browne and Venning dated the appearance of chorionic gonadotropin in the urine of women after fertilization at ten to thirteen days after the elevation of urinary pituitary gonadotropin associated with ovulation.6, 8, 9, 11, 12, 13, 21 With such a paucity of accurate reports dealing with the time of the first appearance of chorionic gonadotropin in the urine and serum of pregnant women, there has been an accompanying lack of serial quantitative surveys of hormone levels during early pregnancy. In the few recorded cases,6, 8, 16, 17, 20, 24, 25 serial assays were begun at forty to fifty days after the first day of the last normal menstrual period. Thus, there is a void in knowledge of the hormone levels between fertilization and the forty-day to fifty-day interval.The purpose of this investigation is to establish the time of first appearance of human chorionic gonadotropin in the urine and serum of women after fertilization and to determine quantitatively the concentrations of hormone throughout early pregnancy. In contrast to most previous reports, in which values are expressed in terms of one or another animal unit, this report will present values expressed in terms of international units. Although it is not possible to compare such values with previous ones, or for that matter to make comparisons among the previously reported values in terms of absolute amounts, the fluctuation curve of hormonal excretion can be compared relatively.

Quantitative studies on the production, destruction, and elimination of chorionic gonadotropin in normal pregnancy

The levels of chorionic serum gonadotropin in normal pregnancy have been determined in 112 patients in terms of International Units. A characteristic curve for this hormone has been obtained, agreeing in both pattern and absolute values with those reported by others. An analysis of the factors which might influence the characteristic hormonal pattern indicates that the renal function with respect to the hormone remains constant during normal pregnancy, that the extrarenal disposal of the hormone accounts for more than 90 per cent of the circulating hormone, and that probably the fluctuating character of hormonal level in serum or urine depends entirely on changes in rates of production of hormone during pregnancy.

The Provitamin A Requirement of Hens ,

IN JUNE, 1944, the Committee on Animal Nutrition of the National Research Council published a report prepared by the sub-committee on poultry nutrition, entitled, “Recommended Nutrient Allowances for Poultry.” The allowances formulated were based on experimental work reported in the literature. Some time earlier, in October, 1943, the present experiment was started to determine the requirement of the laying hen for provitamin A from vegetables sources, for egg production, hatchability, and low mortality.The allowances for vitamin A in terms of International Units per pound of feed recommended by the sub-committee on poultry nutrition are as follows: starting chicks, 1,200; growing chicks, 1,800; and laying and breeding hens, 3,300. To provide for loss during a reasonable period of storage, a margin of safety for vitamin A or provitamin A of 66% was included. Without the margin of safety, the calculated allowances are as follows: for starting chicks, 720; for growing .

Recovery of Carotene and Vitamin A from Butter when Cows were Fed Unlimited Quantities of Green Rye

To simulate pasturage conditions, three cows, two Ayrshires and one Holstein, were fed all the fresh green rye they would consume for 16 days. During the last 3 days the carotene ingested daily, and the carotene and vitamin A output in the milk were computed. Dialy intake of carotene averaged 3.507 gm. equivalent to nearly 6,000,000 international units of vitamin A. The butter produced had an average carotene content per pound of 4700 international units, and 8490 units as vitamin A, making a total vitamin A value of 13,190 international units. Of the carotene ingested daily only an average of 0.086% was recovered daily as carotene in the butter and only an average of 0.154% as vitamin A, or a total of 0.24% in terms of international units. The percentage of the total vitamin A value in the butter due to carotene was quite uniform for the three cows, averaging 35.5%. The data seem to indicate that when excessive amounts of carotene are fed, the ratio of carotene to vitamin A in the butter becomes rather constant at about 1 to 2, at least with Holsteins and Ayrshires (high vitamin A and low carotene breeds).