SU1418615A1 - Method of determining volume of extracellular fluid - Google Patents

Abstract

This invention relates to methods for studying the chemical and physical properties of biological materials. The purpose of the invention is to reduce the morbidity and simplify the method. Sodium bromide is administered orally, and then a blood sample is applied to a substrate of microporous ash-free material. After drying, the sample is irradiated. The concentration of bromine in the blood is determined and the extracellular fluid volume is calculated. A semiconductor detector is used to record the x-rays of bromine.

Description

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The invention relates to medicine to methods for studying the chemical and physical properties of biological materials, namely the volume of extracellular fluid, which can be used in clinical cardiology, nephrology, traumatology, aerospace medicine and, in particular, in space flight conditions.

The aim of the invention is to reduce the morbidity and simplify the method in mass clinical dynamic studies.

The goal is achieved by the method of determining the volume of extracellular fluid, including the introduction of bromine, into the body is administered orally 0.0014-0.014 g / kg body weight of non-radioactive sodium salt of sodium bromide, a blood sample of 10 to 50 µl is taken from a finger, the sample is applied to a substrate of fine microporous ash-free material, dried, irradiated with a sample of photons or charged particles, and the intensity of the excited characteristic bromine radiation determines the concentration of bromine in the blood and calculates by volume of the extracellular fluid by the following formula:

ovzh o ,,

.k.

where Q is the amount of stable bromine administered to the body, mg i C c is the concentration of bromine in the blood

mg / ml

H - hematocrit,%, 0.86 - Olesen coefficient, which takes into account the content of proteins in plasma and the absorption of bromine by erythrocytes. PRI me R 1. A test subject weighing 70 kg received 10 ml of a 10% aqueous solution of sodium bromide. After 6 h of short-circuit of the finger, two blood samples with a volume of 10 µl each were taken using a scarifier and a micropipette. One sample was used to determine hematocrit (H) by the standard procedure. H 40%. Another sample was applied to a substrate of a thin microporous ashless filter in the form of a disk with a diameter of 20 mm fixed in a ring holder made of aluminum.

The substrate with blood samples was dried at 20 ± 2 ° С for 2 h.

The dried samples were irradiated with X-ray tube REIS-I Svetlana. A voltage of 32 kV, a current of 80 µA, a filter for excitation radiation of 150 µA Ag. To register a characteristic x-ray.

bromine radiation used a silicon semiconductor detector SLP-10185 (ORTEC) with a resolution of 185 eB on the 5.9 kzV line with the main amplifier 422 (ORTEC). The spectrum of the characteristic radiation of bromine with an energy of 11.9 keV was recorded and processed on a multichannel amplitude analyzer of impulses LP-4900 with a microprocessor. Time

spectrum measurement 300 s. The statistical error of determining the intensity K of the characteristic x-ray line of bromine is less than 1%. Bromine concentration

in the blood sample in terms of mg / ml, it was 0.0277, and in the plasma with uch, the hematocrit of 40% was 0.04t2. extracellular fluid was 16.8 liters. Example 2. Irradiation of the sample

blood photons.

A test weighing 70 kg received 10 ml of a 1.0% aqueous solution of NaBr. After 6 hours, two blood samples with a volume of 10 µl each were taken from the finger with the aid of scarifiers and micropipettes. One sample was used to determine hematocrit (H) according to a standard procedure. H 40%. Another sample was applied to a substrate of a thin microporous ashless filter in the form of a disk with a diameter of 20 mm fixed in a ring holder made of aluminum. Blood sample supports were dried at 20t2 ° C for 2 h.

The dried samples were irradiated with gamma-quanta (photons) with an energy of 22 eV from

radionuclide source

t

activity 3, Bq (100 MKI). To register the characteristic

An X-ray radiation spectrometer was used, which includes a Si (Li) semiconductor detector, a pulse amplifier, a multichannel amplitude portable analyzer and a digital recorder. The duration of the measurement of each sample is 5 min. The statistical error of determining the intensity K — the characteristic X-ray line of bromine is less than 1%. The concentration of bromine in the blood sample in terms of mg / ml was equal to 0.0462 in terms of hematocrit, 40% in plasma. The volume of extracellular fluid was

16.8l.

Example 3. Irradiation of a blood sample with charged particles.

A test weighing 70 kg received 10 ml of a 10% aqueous solution of sodium bromide. After 6 hours, two blood samples with a volume of 10 µl each were taken from a finger using a scarifier and a micropipette. One sample was used to determine hematocrit by the standard procedure. H 40%. Another sample was applied to the substrate from a thin microporous ashless filter in the form of a disk with a diameter of 20 mm fixed in a ring holder made of aluminum. Substrates with blood samples were dried when over. The dried samples were irradiated with protons (charged particles) with an energy of 1.5–3 meV, obtained on a Van-der-Graaf EG-8 electrostatic accelerator. Silicon semiconductor detector SLP-10185 (ORTEC) with a discharge of 185 eV on the line 5.9 K5; B with the main amplifier 422 (DRTEC) was used to record the characteristic X-rays of bromine. Spectrum of characteristic radiation of bromine with energy

11.9 keV were recorded and processed on a multi-channel amplitude pulse analyzer with a microprocessor. The spectrum measurement time is 300 s. The statistical error in determining the cd line of the characteristic x-ray radiation, bromine is less than 1%. The plasma concentration of bromine in terms of mg / ml was 0.0277, and in plasma, taking into account the hematocrit, 40% - 0.0462. The volume of extracellular fluid was 16.8 liters. ,:

 When using the proposed method in comparison with the known, the amount of injected into the body is reduced.

sodium bromide (10 times), which reduces the time for repeated determination of the volume: extracellular fluid in one person, decreases the invasiveness, because instead of venipuncture is removed from the finger, the volume of blood for analysis decreases by 40-300 times, the complexity of the method decreases: only two simple operations — digging out with an automatic pipette and drying at room temperature, makes it possible to conduct mass clinical and prophylactic studies, since the method of drawing blood from a finger and preparing a sample the analysis is very simple and does not require considerable effort and specially trained personnel.

Claims (1)

Invention Formula The method of determining the volume of extracellular fluid, including the oral administration of bromine into the body as an indicator, blood sampling, determination of the concentration of bromine, that is, in order to reduce the morbidity and simplify the method in mass clinical dynamic studies, from the finger, in part of the sample, hematocrit is determined, another part is applied to a substrate of microporous ash-free material, irradiated with photons, charged particles or X-rays, according to the intensity of the excitation optical radiation is determined by the concentration of the bromine in blood samples, and the volume of extracellular fluid OVZH determined by the formula ovzh 0,86 (-l IH4 / l, C (where H is hematocrit,% j Q - the amount of bromine introduced into the body, mg; C is the concentration of bromine in blood samples, mg / ml.