A novel automated multi-cycle magnetic solid-phase extraction coupled to LC-MS/MS to study the disorders of six functional B vitamins in patients with gastroenterology and hyperhomocysteinemia

B vitamins are essential for human life and their disorders can cause a variety of diseases. Solid-phase extraction (SPE) coupled to LC-MS/MS is a preferred technique for determining multiple B vitamins, however, their complexity in real biological matrices makes it hard to achieve satisfactory recovery and accuracy when simultaneous detection. In this study, a novel automated multi-cycle magnetic SPE (MSPE) coupled to the LC-MS/MS method was established using a mixed-mode anion exchange magnetic adsorbent for the simultaneous extraction of six functional B vitamins, including methylmalonic acid, riboflavin, pantothenic acid, 4-pyridoxic acid, folic acid, and 5-methyltetrahydrofolate. After three consecutive MSPE cycles, the recoveries of all analytes were between 51.5% and 89.6%. The method exhibited excellent sensitivity and linearity, with a dynamic range of 200-fold (R > 0.99 for all analytes), exceptional accuracy (ranging between 95.4% and 105.6%) and precision (with RSDs ≤ 6.2%) without significant matrix effects or interferences. Compared to manual SPE method, the automated multi-cycle MSPE method has better feasibility and greater vitamin coverage. It shows a high correlation with the manual method for the detection of 5-methyltetrahydrofolate and folate (R > 0.99). A study of patients from the gastroenterology department showed that those undergoing surgery and those with malignancies may be at risk of folate deficiency. In addition, patients with hyperhomocystinemia had higher levels of methylmalonic acid and lower levels of 5-methyltetrahydrofolate, which correlated with homocysteine levels (R = 0.404 and -0.311, respectively) and showed dose-response relationships. This method is highly automated and cost-effective, with minimal systematic error, making it suitable for the analysis of clinical samples.

A phase I study comparing the pharmacokinetics and safety of HS628 (tocilizumab biosimilar) and reference tocilizumab in healthy male subjects

This study aimed to evaluate the pharmacokinetic (PK) similarity of the proposed biosimilar HS628 compared with the reference tocilizumab (Actemra®) and also to demonstrate similar safety and immunogenicity profiles in healthy Chinese male subjects. Eighty eligible subjects were randomized into two treatment groups in a 1:1 ratio to receive a single intravenous infusion of HS628 or tocilizumab at 4 mg/kg over 60 min. Blood samples were collected at the scheduled time points for PK and immunogenicity analysis. PK biosimilarity was determined using the standard bioequivalence criteria 80%-125%. A total of 77 subjects received the study drug and completed the study. The main PK parameters were similar for the test and reference groups. The ratio of geometric least-squares means (GMR) and its 90% CIs for AUC0-t , AUC0-∞ , and Cmax between the test group and reference group were 1.06 (1.00-1.12), 1.07 (1.00-1.14), and 1.04 (0.99-1.10), respectively, which were fully within the predefined bioequivalent range of 80%-125%. The incidence of treatment-emergent adverse events (TEAEs) was similar for HS628 and tocilizumab (p > 0.05). The most common TEAEs were decreased fibrinogen, decreased neutrophils, pharyngalgia, oral ulcer, decreased leukocytes, and increased erythrocyte sedimentation rate. The results of the present study provide strong evidence to support the PK similarity and bioequivalence of HS628 and tocilizumab. The safety and immunogenicity profiles of HS628 were also shown to be similar to those of the reference tocilizumab.

A single-dose, randomized crossover study in healthy Chinese subjects to evaluate pharmacokinetics and bioequivalence of two capsules of calcium dobesilate 0.5 g under fasting and fed conditions

OBJECTIVES

To compare the rate and extent of absorption of a launched generic calcium dobesilate capsule versus the branded reference formulation under fasting and fed conditions in healthy Chinese subjects, and to assess their bioequivalence and tolerability.

METHODS

This single-dose, open-label, randomized-sequence, 2-period crossover bioequivalence study was conducted on healthy Chinese volunteers aged 18 to 45 years. Subjects received a single 0.5 g dose of calcium dobesilate capsule under fasting or fed conditions, with a 3-day washout period between doses of the test (T) and reference (R) formulations. Blood samples were collected before and up to 24 hours after administration. The plasma concentration of calcium dobesilate was determined by a validated Liquid chromatography-tandem mass spectrometry method. Non-compartmental analysis was applied to identify the pharmacokinetic (PK) properties. The primary PK parameters including the maximal plasma concentration (Cmax), the area under the plasma concentration-time curve (AUC0-t), and the AUC extrapolated to infinity (AUC0-inf) were used for bioequivalence evaluation.

RESULTS

The mean of PK parameters for T and R capsules under fasting (fed) condition were: Cmax, 13.57 (6.71) and 12.59 (7.25) μg/mL; AUC0-t, 97.32 (79.74) and 96.97 (80.71) h*μg/mL; AUC0-inf, 101.68 (88.01) and 101.64 (87.81) h*μg/mL. The 90% confidence intervals (CIs) of GMRs under fasting (fed) condition were: Cmax, 97.91%-116.62% (88.63%-96.53%); AUC0-t, 97.15%-104.00% (96.58%-101.39%); and AUC0-inf, 97.19%-102.89% (98.67%-103.99%). These 90% CIs were all within the bioequivalence range of 80%-125%. All adverse events were mild.

CONCLUSION

In this study, the T calcium dobesilate 0.5 g capsule was bioequivalent to the reference product under both fasting and fed conditions. Taking food would slow down its rate and reduce its amount of absorption. Both formulations were generally well tolerated.

Effect of food on the single-dose pharmacokinetics and tolerability of savolitinib in Chinese healthy volunteers

The aim of this study was to investigate the effect of a high-fat and high-calorie meal on the single-dose pharmacokinetics (PK) and tolerability of savolitinib. The study included two phases: safety run-in phase and food effect assessment phase. In the safety run-in phase, 9 healthy male volunteers were divided into three groups to be administered a single oral dose of savolitinib tablets at 200, 400, and 600 mg. In the food effect assessment phase, 16 healthy male volunteers received a single 600 mg dose of savolitinib tablets following an overnight fast or a high-fat and high-calorie breakfast prior to dosing. Blood samples were collected at the designated time points for pharmacokinetic analysis. Safety and tolerability were assessed throughout the study by clinical assessments and adverse events (AEs). A total of 25 healthy male volunteers were enrolled in the study, including 9 in the safety run-in phase and 16 in the food effect assessment phase. In the food effect assessment phase, the geometric mean ratios (90% confidence interval) for savolitinib dosed under the fed condition compared with that dosed under the fasting condition were 102.7% (84.9%, 124.2%) and 117.1% (103.9%, 131.9%) for C_max and AUC_0-inf of savolitinib, respectively. The T_max was delayed significantly (p = 0.023) under fed condition. The most common AEs possibly related to the study drug were dizziness, nausea, and emesis. The study indicated that a high-fat and high-calorie meal has no clinically relevant impact on the PK and bioavailability of savolitinib in healthy male volunteers.

[The association between single nucleotide polymorphism of interleukin-1β gene rs1143627 site and susceptibility to active tuberculosis]

Objective: To investigate the relationship between single nucleotide polymorphism (SNP) of IL-1β gene and susceptibility to tuberculosis. Methods: A case-control study was conducted in Shenzhen Third People's Hospital from January 2012 to December 2014. A total of 1 533 patients with active tuberculosis were enrolled, including 1 432 cases of pulmonary tuberculosis[920 males and 512 females, mean age (37±14) years] and 101 cases of extrapulmonary tuberculosis [60 males and 41 females, mean age (35±13) years]. At the same time, 1 445 healthy controls (882 males and 563 females, mean age (37±20) years) were selected. The genotypes of rs1143627, rs1143623, rs16944 and rs2853550 of IL-1β gene were detected by time-of-flight mass spectrometry. The allele frequencies of rs1143627 T>C (-31) were compared between patients with pulmonary tuberculosis and those with extrapulmonary tuberculosis. Fifty-three patients with active tuberculosis [male 32, female 21, mean age (37±15) years] were randomly selected, and the correlation between SNP alleles and tuberculosis severity was analyzed before and after treatment. Results: Time-of-flight mass spectrometry effectively detected the genotypes of 4 SNP loci. Among the 4 SNP loci, only the allele frequency of -31 locus was significantly different between the active tuberculosis group and the control group. The allele frequency of rs1143627 T locus in active tuberculosis group was 53.3%(1 634/3 066), which was significantly higher than that in the healthy control group 48.7%(1 407/2 890; OR=1.20, 95%CI=1.09-1.33, P=0.001 6) .The frequencies of the other 3 SNP alleles were not significantly different between the active tuberculosis group and the control group. The frequencies of the other 3 SNP alleles were 59% (1 821/3 066) and 60% (1 732/2 890) for rs1143623 G allele, 51% (1 574/3 066) and 52% (1 499/2 890) for rs16944 G allele, and 64% (1 964/3 066) and 65% (1 875/2 890) for rs2853550 T allele respectively. Stratified analysis showed that the frequency of the -31 T allele in patients with extrapulmonary tuberculosis (62.9%, 127/202) was significantly higher than that in patients with pulmonary tuberculosis (52.6%,1 507/2 864) (OR=1.53; 95% CI=1.13-2.05; P=0.005).The HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 26.6, 13.9 and 13.3 respectively before anti-tuberculosis treatment, and after 2 years of anti-tuberculosis treatment, the HRCT scores of patients with rs1143627 TT, TC and CC genotypes were 14.7, 6.6 and 5.4 respectively, which indicated that TB patients with rs1143627T allele were associated with more severe pulmonary disease. Conclusion: The SNP of IL-1β-31T>C was associated with susceptibility to active tuberculosis, and T allele was the susceptible gene and individuals carrying T allele were more likely to develop extrapulmonary tuberculosis.

Influence of salmonid aquaculture activities on a rock-cliff epifaunal community in Jervis Inlet, British Columbia

Benthic video surveys were carried out at two marine finfish aquaculture and associated reference sites in Jervis Inlet (JI), British Columbia. Substrate composition, epifaunal diversity, mat-forming taxa (primary indicators: opportunistic polychaete complexes (OPCs) and sulfide-oxidizing bacteria) and waste pellets were quantitatively assessed. Hard-bottom substrates were dominated by rock wall, skeletal sponge matrix, graded bedrock, rock-veneer, and cobble. Aquaculture waste outputs (modelled depositional carbon fluxes and observations of waste feed/faecal pellets) were correlated with benthic organic enrichment indicators (OPC and sulfide-oxidizing bacteria). Sulfide-oxidizing bacteria varied in abundance up to a modelled depositional carbon flux of ~2gCm^-2day^-1 where it sustained 50% areal coverage. Glass sponges revealed an inverse relationship with aquaculture waste outputs and sulfide-oxidizing bacteria. Plumose anemones and shrimp showed a low frequency of occurrence at reference sites; however, they were abundant within the near-field zone of the aquaculture sites associated with a higher modelled carbon flux. Future research should focus on the response of various taxa to depositional gradients and their potential role as secondary indicators of aquaculture activities associated with rock-cliff communities.

The prevalence of latent tuberculosis infection in rural Jiangsu, China

OBJECTIVES

Diagnosis and interventional treatment of latent tuberculosis (TB) infection (LTBI) are important components in tuberculosis control. But systematic studies regarding the epidemic of LTBI are still rare in China. The objective of this study was to assess the prevalence and risk factors associated with LTBI based on the results of a domestic TB-specific gamma interferon (IFN-γ) release assay (TB-IGRA) in rural Jiangsu, China.

STUDY DESIGN

Cross-sectional study of subjects registered in eight villages in Jiangsu, China.

METHODS

This study was conducted in 2012 in eight villages. After recruitment, individuals with active TB or a history of TB were excluded. The TB-IGRA was performed for diagnosis of LTBI.

RESULTS

2169 of 2185 subjects met the requirement and were analysed in this study. 524 (24.3%) had a positive result, and positive rate gradually increased with age (P for trend <0.001). Multivariate analyses showed that increasing age, male gender and a history of TB exposure were risk factors associated with LTBI. Bacillus Calmette-Guérin (BCG) vaccination did not reduce the risk of TB infection in participants (aged ≥20 years).

CONCLUSIONS

The findings of this study demonstrate that the prevalence of LTBI in China might be overestimated by tuberculin skin test compared with IFN-γ release assay (IGRA). The degree of TB exposure is related to Mycobacterium tubercuium (MTB) infection, and BCG vaccination offers little protection against MTB infection in adults. The early and effective detection and treatment of active TB patients, and screening and intervention for LTBI patients with a high risk of developing active TB could be cost-effective methods for TB control in China.

LC-MS/MS Method for Serum Creatinine: Comparison with Enzymatic Method and Jaffe Method

Accurate quantification of creatinine (Cre) is important to estimate glomerular filtration rate (GFR). Differences among various methods of Cre quantification were previously noted. This study aims to develop a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for serum Cre and compare this method with clinical routine methods. LC-MS/MS analysis was performed on API 4000 triple quadrupole mass spectrometer coupled with an Agilent 1200 liquid chromatography system. After adding isotope-labeled Cre-d3 as internal standard, serum samples were prepared via a one-step protein precipitation with methanol. The LC-MS/MS method was compared with frequently used enzymatic method and Jaffe method. This developed method, with a total run time of 3 min, had a lower limit of quantification of 4.4 μmol/L, a total imprecision of 1.15%–3.84%, and an average bias of 1.06%. No significant matrix effect, carryover, and interference were observed for the LC-MS/MS method. The reference intervals of serum Cre measured by LC-MS/MS assay were 41–79 μmol/L for adult women, and 46–101 μmol/L for adult men. Using LC-MS/MS as a reference, the enzymatic method showed an average bias of -2.1% and the Jaffe method showed a substantial average bias of 11.7%. Compared with the LC-MS/MS method, significant negative bias was observed for the enzymatic and Jaffe methods in hemolytic and lipimic samples. We developed a simple, specific, and accurate LC-MS/MS method to analyze serum Cre. Discordance existed among different methods.

Feasibility study of the pharmacology of local application of amifostine (WR-2721) to the buccal mucosa in guinea pigs

BACKGROUND/AIMS

We have undertaken this study to investigate the feasibility of topical application of the radioprotective compound WR-2721 to the buccal mucosa.

METHODS

Saliva samples were collected from 5 volunteers and were reconstituted in 3 amifostine solutions. Measurements of amifostine and WR-1065 contents were performed at 6 different time points. Young-adult guinea pigs were topically administered amifostine 50 and 100 mg to each buccal mucosa. At 0, 15 and 30 min after application, the blood samples obtained from the heart and the buccal tissues were prepared for the analysis of amifostine and WR-1065.

RESULTS

There was no significant difference between the 3 concentrations of amifostine in saliva in vitro at any of the 6 study time points (p > 0.05). No WR-1065 was detected in saliva. In the guinea pigs from groups A and B, there were significant differences in concentrations of amifostine and WR-1065 in the tissues between the 0-min and 15-min subgroups and between the 0-min and 30-min subgroups (p < 0.05). The concentrations of amifostine and WR-1065 from the 15-min and 30-min subgroups did not differ statistically (p > 0.05).

CONCLUSIONS

It is feasible to administer topical amifostine (WR-2721) to mucosa to prevent radiation-induced oral mucositis, and systemic absorption is negligible. Relatively high concentrations of amifostine in human saliva in vitro were maintained, although some inconsistent changes are observed.

Human telomerase RNA gene (TERC) gain and polysomy of chromosome 3 in cervicovaginal liquid-based pap preparations: a fluorescence in situ hybridization study

PURPOSE. This study investigated human telomerase RNA gene (TERC) gain and polysomy of chromosome 3 in cervicovaginal liquid-based pap preparations in Guilin, China, and assessed the relationship between FISH findings and clinical diagnoses. METHODS. Slides prepared from 63 liquid-based preparations with cytologic diagnoses of negative for squamous intraepithelial lesion or malignancy (NILM n = 9), atypical squamous cells of undetermined significance (ASCUS, n = 18), low-grade squamous intraepithelial lesion (LSIL, n = 14), high-grade squamous intraepithelial lesion (HSIL, n = 9), and cervical squamous cell carcinoma (SCCA, n = 13) were analyzed for TERC gain and polysomy of chromosome 3 using a commercially available two-color FISH probe. The results of the cytologic analysis and those of concurrent or subsequent biopsies, when available, were compared with the FISH findings. The Mann-Whitney test was used to assess associations between FISH findings and diagnoses. RESULTS. TERC gain and polysomy of chromosome 3 were significantly associated with the cytologic diagnosis (p? 0.001). Patients with HSIL or SCCA cytology diagnoses had a significantly higher percentage of cells with TERC gain and polysomy of chromosome 3 than did patients with NILM, ASCUS or LSIL cytologic diagnoses. Those abnormal cases with CIN1 histological diagnosis had a significantly lower percentage of cells with TERC gain and polysomy of chromosome 3 than did patients with a CIN2, CIN3 and SCCA histological diagnosis. CONCLUSIONS. TERC gain and polysomy of chromosome 3 may be important associated genetic events in cervical intraepithelial neoplasia and carcinoma. FISH is a potential tool for the diagnoses of uterine cervix disease.

[The detection of virus antigen in the lower respiratory tract of the patients with lung cancer]

OBJECTIVE

To find out about the viral infection situation of lower respiratory tract of the patients with lung cancer.

METHODS

The excretion from the surface of bronchiogenic carcinoma was brushed under fibrobronchoscopy. The respiratory virus antigen was detected and analysed by reagent kit produced by the 262nd Hospital of Beijing Military Region.

RESULTS

The respiratory virus antigen was positive in eight cases of lung cancer group, the positive rate was 17.4%(8/46), it was significantly higher than that in non-lung cancer group (P < 0.05). Among them, there were one case of influenza virus A, two cases of influenza virus B, two cases of para-influenza 1,3, two cases of adenovirus and one case of respiratory syncytial virus. The carcinoma accompanied with viral infection were 4,3,1, cases in order of squamous carcinoma, small cell lung carcinoma and adenocarcinoma.

CONCLUSION

The results showed that a relationship existed between lung cancer and viral infection of respiratory tract statistically. The viral infection increased in patients with lung cancer, this is worthy to pay attention to.

p53 overexpression and downregulation of inter-alpha-inhibitor are associated with hyaluronidase enhancement of TNF cytotoxicity in L929 fibroblasts

Degradation of extracellular matrix by hyaluronidase increases murine L929 cell sensitivity to tumor necrosis factor (TNF) cytotoxicity. Seeding and culturing L929 cells onto the matrix of serum fetuin and the hyaluronate-binding inter-alpha-inhibitor resulted in inhibition of hyaluronidase-enhanced TNF killing, suggesting that the release of these proteins from hyaluronidase-degraded matrix confers cellular TNF susceptibility. Metabolic labeling studies showed that hyaluronidase mediated de novo protein synthesis and down regulated several proteins in L929 cells. Specifically, hyaluronidase upregulated p53 protein expression (>200%) but down regulated a p85 inter-alpha-inhibitor-like protein (>90%) in L929 cells, whereas it had no effect on the protein levels of ICH-1, Bcl-xL, Bcl-2, Fas ligand, CAS (cellular apoptosis susceptible protein), TIAR (an RNA-binding protein) and alpha-tubulin. Conceivably, hyaluronidase enhancement of TNF sensitivity in L929 cells is p53-dependent and the matrix inter-alpha-inhibitor contributes a protective role against TNF cytotoxicity.

[Factors influencing morale among the elderly in long-term care]

The purpose of this research was to investigate the factors which influence morale among the elderly in long-term care. The sampling criteria for subjects were that they were (1) 65 years old or older and were residents or care recipients at a nursing home, day care or home care center which participated in the experimental project in Department of Health; (2) able to understand the Mandarin or Taiwanese language; (3) capable of verbal communication; and (4) family caregivers whose elder family met the above three requirements. A total sample of 174 subjects consisting of 87 elderly and 87 caregivers were chosen. Research findings revealed: the mean score for morale for elderly in this study was 11.71 out of range 2-19. Except for birthplace and caring models, there was no significant difference among the elderly. The elderly born in Taiwan had significantly higher morale than those born in Mainland China. The elderly in day care had significantly higher morale than those in home care and nursing homes. No significant difference was found among family caregivers, except for family caregivers who had changed their job due to the demands of caring for elderly relations. Elderly in this situation showed significantly lower morale in the elderly whose family caregivers did not change jobs. Correlation analysis showed a positive relationship between the elderly's level of daily activity and their morale level. Higher morale in the elderly was also found to be positively related to perceived higher levels of social support in family caregivers. In multiple regression, morale among the elderly was used as the criterion variable, while the variables of birth place, functional status, caregivers' perceived social support, home care, nursing home, changed job, never having had a job, caregivers' sex caregivers' educational level were used as predictors. The explanation variance achieved using the above research model was 30.78%. Recommendations derived from this study include suggesting the establishment of community adult day care centers to facilitate the elderly being able to stay within their communities, and to provide mental support for caregivers.

Analysis on decay rate of vibration following impact to human dry skull with and without mouthguards

The modal analysis on vibration in the human dry skull with and without mouthguards was performed in order to clarify which elasticity modulus of the material and what form of the mouthguard are best. Nine different mouthguards were prepared for this study from three materials with different elasticity moduli amd three different forms: Soft MOLTENO (registered) mouthguards of long, middle, and short forms. Regular MOLENTO (registered) mouthguards of long, middle and short forms, and Hard MOLENTO(registered) mouthguards of long, middle and short forms. Thirty-five measurement points were established on the skull. The main measurement system was composed of a 512-D Vibration Generator, LV-1300 Laser-Doppler Vibrometer, CF-6400 FFT Analyzer, PC-9821Xn personal computer, and Vibrant PC modal analysis software. The decay rate was calculated to evaluate effectiveness of the absorption of vibration of the skull with and without mouthguards when stress was put on the skull. The results showed that he skull fitted with the long and middle mouthguards made of regular MOLTENO (registered) had a higher decay rate than the skull w the mouthguard, and that the material properties of the mouthguards influenced the absorption of the skull vibration more intensively that did the forms of the mouthguards.

A new method of purification and sensitive bioassay of platelet-activating factor (PAF) in human whole blood

There is no satisfactory assay procedure of PAF in human whole blood in terms of sensitivity, reproducibility and simplicity. This is due to coexisting lipids from plasma and cellular membranes which inhibit measurement of PAF in various assay procedures, including bioassay. In the present study, an attempt was made to eliminate these interfering lipid inhibitors from blood samples. Lipids in human whole blood were extracted according to the method of Bligh & Dyer and the organic layer was dried under a stream of nitrogen. Then, the dried organic layer was dissolved in diethyl-ether and the solution was kept at -20 degrees C which was then centrifuged. The resulting supernatant was then applied to an anion-exchange column and the PAF fraction was obtained by step-wise gradient elution. The fraction was further purified by normal phase HPLC. Then PAF in the final sample was determined by sensitive bioassay using rabbit platelets containing fibrinogen and epinephrine. The recovery rate of PAF throughout this procedure was constant and satisfactory (37.4 +/- 9.7%), which was confirmed using [3H]-PAF. The lower limit of the present assay was estimated to be 5pg in 1 ml of blood and it was sensitive enough to detect PAF in blood samples from healthy volunteers and patients with sepsis or liver cirrhosis. Furthermore, attempts were made to compare the sensitivity and the recovery of our method with these of a commercially available radioimmunoassay (RIA) kit for PAF. However, it was not possible to detect any amount of authentic PAF added to whole blood.

[Effect of yin and qi tonifying herbs on hyperthyroid model of yin-deficient rats]

The article reports the effect of Yin and Qi tonifying herbs (Radix Rehmanniae, Radix Ophiopogonis and Pseudostellaria Heterophylla) on hyperthyroid model of Yin-deficient rats. The model rats were made Yin-deficient by injecting thyroxine. Observation showed that after injection, indexes such as anus temperature, oxygen consumption, weight, diet, activity, general conditions, triiodothyronine (T3) and thyroxine (T4) in serum were markedly changed. It is thus suggested that the Yin and Qi tonifying mixture of the above three herbs can regulate and correct Yin-deficiency in hyperthyroid model of Yin-deficient rats.

Species differences in platelet aggregation induced by platelet-activating factor (PAF)

Species differences in platelet aggregation induced by platelet-activating factor (PAF) were investigated by using the same procedure of platelet preparation and biological assay. Washed platelets of six different species (horses, dogs, rats, rabbits, sheep and guinea pigs) were prepared employing the same method and platelet aggregation was induced by C16-PAF. Horse platelets were most sensitive to PAF (8.0 x 10(-12) M) and rabbit platelets activated by 5.0 x 10(-11) M PAF were also sensitive enough to detect PAF in clinical samples.

Simple and rapid measurement of platelet-activating factor (PAF) in whole blood

A simple assay of platelet-activating factor (PAF) in whole blood was developed, employing acetone extraction and thin layer chromatography (TLC) purification of blood sample. The activity of acetylhydrolase present in blood sample was almost completely suppressed by ice-cold acetone extraction, and other inhibitory substances interfering the activity of PAF were effectively removed from the acetone extract by TLC. Then, the treated samples were subjected to a conventional PAF bioassay using rabbit platelets. The recovery rate of PAF by the above procedure was constant and feasible (46-48%). The lower limit of the present assay was estimated to be 1.0 x 10(-10) M. Employing the present method, it was able to determine the amount of PAF in blood (1.2-6.0 x 10(-10) M) of 6 out of 14 septic patients, while no significant PAF activity was detected in the samples from 6 healthy subjects. These results indicate a potential application of the present method in the clinical assay of PAF in blood.