Keizo Sato

High-performance liquid chromatographic determination of cephalosporin antibiotics using 0.3 mm I.D. columns

Four cephalosporins, cefazolin, ceftizoxime, cefaloridine and cefaclor, were determined using a novel microbore high-performance liquid chromatographic system designed to be entirely compatible with direct liquid interfacing (DLI) for mass spectrometric analysis. The chromatographic support was a 5-micron C18 column of 0.3 mm I.D., compared with the usual microbore column diameters of 1-2 mm. The mobile phase contained no buffers or salts which may have caused column blocking or mobile phase crystallization, and the use of a concentration column allowed the injection of large volumes of analyte (up to 500 microliters). The assay was reproducible, the relative standard deviations being less than 20% within-day and between-day for all the drugs. The detection limit for cefaloridine and cefazolin was 1 ng and for cefaclor and ceftizoxime 5 ng.

Positive- and negative-ion mass spectrometry of 24 benzodiazepines

Abstract Positive-ion electron impact (PIEI), positive-ion chemical ionization (PICI) and negative-ion chemical ionization (NICI) mass spectra of 24 benzodiazepines are presented. In the PIEI mode, peaks due to M, M − H, M − CO and a liberated R 3 -phenyl ring appeared in many compounds. The peaks at mz M − 47 and mz 56 or 70 were characteristic for nitro- and oxazolo-compounds, respectively. In the PICI mode, most spectra showed the base peaks due to M + H and small peaks due to M + C 2 H 5 ; small peaks due to M − R 1 or M − R 1 + 2H also appeared for many compounds. For the nitro-compounds, peaks at mz M − 29 commonly appeared. For the oxazolo-compounds, peaks due to the loss of the R 3 -phenyl ring appeared. In the NICI mode, either molecular or [M − H] − quasi-molecular anions were the base peaks in 10 compounds. Small anions at mz M + 15 (M − H + O) also appeared in many compounds. Anions due to liberated halogens were observed for most compounds; bromine gave its base peaks. An procedure for benzodiazepines from human urine and plasma, and their separation by gas chromatography (GC) with a wide-bore capillary column are also presented to serve for their actual identification by GC/mass spectrometry (MS). The wide-bore capillary column was useful to prevent the drugs from decomposition.

A practical method for the accurate determination of methemoglobin in blood containing carboxyhemoglobin

Kinetics of the oxidation of carboxyhemoglobin (HbCO) by potassium ferricyanide was studied photometrically in a weakly acid solution. An increase in the absorbance at 630 nm reached a maximum within 10 min when over a 100-fold excess of ferricyanide to hemoglobin iron was used. A slight decrease in the absorbance was observed after completion of the reaction when over a 500-fold excess of the reagent was used. In the presence of 0.4% Sterox SE, the absorbance began to decrease without complete oxidation. From these findings, a simple, rapid and accurate method for the determination of methemoglobin (Met-Hb) in blood was devised. The method was compared with two other methods, using 11 blood samples containing various amounts of HbCO, and proved to be suitable for blood containing elevated HbCO as well as for ordinary blood.

Enzyme-linked immunosorbent assay for determination of plasma thyroglobulin and its application to postmortem diagnosis of mechanical asphyxia

A high sensitive enzyme-linked immunosorbent assay (ELISA) for determination of plasma thyroglobulin was devised and applied to the postmortem diagnosis of mechanical asphyxia. The sensitivity of the present ELISA was 5 ng/ml. All of the 15 victims who died from causes other than mechanical asphyxia showed plasma thyroglobulin levels lower than 200 ng/ml (99.8 +/- 37.9 ng/ml), while 12 out of 14 victims of mechanical asphyxia showed the levels higher than 200 ng/ml (2100 +/- 3450 ng/ml in 14 victims). Thus, the present ELISA appears to be useful for postmortem diagnosis of mechanical asphyxia.

Long-term storage of blood samples as whole blood at extremely low temperatures for methemoglobin determination

Changes in methemoglobin (Met-Hb) concentrations during storage of whole blood and a hemolysate at refrigerated or various freezing temperatures were examined using experimentally prepared blood samples. When whole blood was stored at 3 degrees C, rapid reduction of Met-Hb was observed in the nitrite-treated blood whereas neither reduction nor formation of Met-Hb was observed in the untreated and heated blood within 7 days. When hemolysate was stored at 3 degrees C, Met-Hb concentrations were stable within a few days regardless of the initial values. However, slight autoxidation was observed 7 days after storage in the untreated and heated blood. When whole blood was stored at various freezing temperatures, Met-Hb concentrations were practically stable until at least 30 days at -80 degrees C or -196 degrees C regardless of the initial values, although considerable autoxidation was observed at -30 degrees C especially in the blood containing small amounts of Met-Hb. Based on the results obtained, a new method was devised for long-term storage of whole blood at extremely low temperatures for Met-Hb determinations.

A simple spectrophotometric method for the determination of carboxyhemoglobin in blood

The spectrophotometric method for the determination of carboxyhemoglobin (HbCO) in blood reported by Fretwurst and Meinecke was modified so as to give the same values of percentage HbCO (HbCO%) as those determined by the oxygen electrode method. Values of HbCO% of nine practical samples determined by both the oxygen electrode method and the present method were nearly identical regardless of the presence of methemoglobin (Met-Hb) in blood. The present method is suitable for forensic practice.

Kinetic analysis of the shift of aerobic to anaerobic metabolism in rats during acute cyanide poisoning

Abstract Blood concentrations of cyanide, lactate, glucose, oxypurines and allantoin were determined in rats sampled at 10 min after the intraperitoneal administration of various concentrations of potassium cyanide. Lactate and oxypurines in plasma increased biquadratically with increase in the cyanide concentration in blood. The concentrations of cyanide for half maximal effect were 1.63 μg/ml for lactate and 2.09 μg/ml for oxypurines. Plasma glucose increased quadratically with increase in the cyanide concentration, and the marked increase was observed where plasma lactate concentration became near maximal. Plasma allantoin concentrations were not significantly changed throughout the experiments. The present results indicate that determination of plasma oxypurines as well as lactate is an excellent parameter for tissue hypoxia.

Identification of human urinary stains by enzyme-linked immunosorbent assay for human uromucoid

An enzyme-linked immunosorbent assay (ELISA) of the sandwich type for identification of human urinary stains using commercially available anti-human uromucoid was developed. When experimentally prepared urinary stains of humans and animals, 2 by 2 cm in area, were subjected to analysis, human stains could be differentiated from animal ones except chimpanzee and Old World monkey ones. Stains of other human body fluids showed negative reactions. The reactions did not decrease when human urinary stains were stored at room temperature for three months. The present ELISA provides a useful presumptive test for urinary stains of human origin.

Detection of Thyroglobulin in Bloodstains as an Aid in the Diagnosis of Mechanical Asphyxia

Mechanical forces applied to the neck region are known to release certain amounts of thyroglobulin into circulation. In this experiment, an attempt was made to detect thyroglobulin in bloodstains as an aid in the diagnosis of mechanical asphyxia. Experimental bloodstains containing thyroglobulin at concentrations of 1, 2, 5 and 10 mu g/mL were prepared on a sheet of filter paper. Small pieces of bloodstains, measuring approximately 2.4 cm2 in area, were extracted with 0.1 mL of distilled water and the extracts were tested against an antihuman thyroglobulin serum by precipitation-electrophoresis. Bloodstains containing more than 1 mu g/mL of thyroglobulin formed distinct precipitin lines for up to one month of storage, while bloodstains containing more than 5 mu g/mL of thyroglobulin formed distinct precipitin lines for up to three months of storage. The present results suggest that the bloodstains can be utilized in the diagnosis of mechanical asphyxia.

Determination of total hemoglobin in forensic blood samples with special reference to carboxyhemoglobin analysis.

For the determination of total hemoglobin (Hb) in blood containing elevated carboxyhemoglobin (COHb), a newly developed reagent containing a 100-fold concentration of ferricyanide (20 g/l) and a 2-fold concentration of Sterox SE was compared with a standard reagent (0.2 g/l ferricyanide), the reagent of van Kampen and Zijlstra, using forensic blood samples and experimentally heated blood samples. There were no significant differences between the spectra of hemiglobincyanide (HiCN) solution produced with our reagent and the van Kampen and Zijlstra reagent using experimentally heated blood samples. Although the spectra of HiCN changed gradually with increased heating time and with the passage of time after mixing, the absorbance at 540 nm (A540) did not change until at least 120 min for both the reagents. When forensic blood samples containing elevated COHb were mixed with the van Kampen and Zijlstra reagent, total-Hb concentrations determined 5 min after mixing were 10-20% higher than those determined after 180 min. The overestimates of total Hb determined after 5 min resulted in comparable underestimates of percentage saturation of COHb (COHb%) when COHb% was obtained from the ratio of COHb content, determined by gas chromatogrpahy, to total-Hb concentration in blood. However, there was an extremely good correlation between the values of total Hb in forensic blood samples determined with the van Kampen and Zijlstra reagent after 180 min and those determined with our reagent after 5 min. From the results obtained, our reagent proved to be suitable for the determination of total Hb in forensic science practice.