Population pharmacokinetics of Amisulpride in Chinese patients with schizophrenia with external validation: the impact of renal function

Introduction: Amisulpride is primarily eliminated via the kidneys. Given the clear influence of renal clearance on plasma concentration, we aimed to explicitly examine the impact of renal function on amisulpride pharmacokinetics (PK) via population PK modelling and Monte Carlo simulations. Method: Plasma concentrations from 921 patients (776 in development and 145 in validation) were utilized. Results: Amisulpride PK could be described by a one-compartment model with linear elimination where estimated glomerular filtration rate, eGFR, had a significant influence on clearance. All PK parameters (estimate, RSE%) were precisely estimated: apparent volume of distribution (645 L, 18%), apparent clearance (60.5 L/h, 2%), absorption rate constant (0.106 h-1, 12%) and coefficient of renal function on clearance (0.817, 10%). No other significant covariate was found. The predictive performance of the model was externally validated. Covariate analysis showed an inverse relationship between eGFR and exposure, where subjects with eGFR= 30 mL/min/1.73 m2 had more than 2-fold increase in AUC, trough and peak concentration. Simulation results further illustrated that, given a dose of 800 mg, plasma concentrations of all patients with renal impairment would exceed 640 ng/mL. Discussion: Our work demonstrated the importance of renal function in amisulpride dose adjustment and provided a quantitative framework to guide individualized dosing for Chinese patients with schizophrenia.

Simultaneous measurement of amino acid enantiomers in the serum of late-life depression patients using convenient LC–MS/MS method with Nα-(5-fluoro-2,4-dinitrophenyl)-l-leucinamide Derivatization

D-amino acids may be indicators of late-life depression but separation and quantification of enantiomers which differ only by optical rotation sign remain challenging due to their identical physical and chemical properties. A convenient LC-MS/MS method was developed for the simultaneous measurement of l- and d-amino acids based on the chiral derivatization reagent, N^α-(5-fluoro-2,4-dinitrophenyl)-L-leucinamide, and conventional octadecylsilane reversed-phase column. Methanol was used as the extraction solvent and a single-step derivatization reaction using volatile triethylamine eliminated the requirement for desalination prior to LC-MS/MS. Simultaneous separation and identification of 21 amino acids and the enantiomeric compositions of the 18 chiral proteogenic entities were achieved. Low limits of detection (0.03-4.0 nM), wide linear range (0.01-20 μM), good precision (RSDs < 10 %) and negligible matrix effects indicated the suitability of the method. Application of the method to the quantification of serum chiral amino acids in late-life depression patients (n = 40) and controls (n = 35) found a total of 17 L-amino acids, 14 D-amino acids, DL-asparagine, glycine and γ-aminobutyric acid. The statistical evaluation showed significant differences of glycine, L-threonine and D-methionine between late-life depression patients and controls, indicating that these are potential biomarkers of late-life depression.

Population pharmacokinetics of buprenorphine and naloxone sublingual combination in Chinese healthy volunteers and patients with opioid use disorder: Model-based dose optimization

The sublingual combination of buprenorphine (BUP) and naloxone (NLX) is a new treatment option for opioid use disorder (OUD) and is effective in preventing drug abuse. This study aimed to explore rational dosing regimen for OUD patients in China via a model-based dose optimization approach. BUP, norbuprenorphine (norBUP), and NLX plasma concentrations of 34 healthy volunteers and 12 OUD subjects after single or repeated dosing were included. A parent-metabolite population pharmacokinetics (popPK) model with transit compartments for absorption was implemented to describe the pharmacokinetic profile of BUP-norBUP. In addition, NLX concentrations were well captured by a one-compartment popPK model. Covariate analysis showed that every additional swallow after the administration within the observed range (0-12) resulted in a 3.5% reduction in BUP bioavailability. This provides a possible reason for the less-than-dose proportionality of BUP. There were no differences in the pharmacokinetic characteristics between BUP or NLX in healthy volunteers and OUD subjects. Ethnic sensitivity analysis demonstrated that the dose-normalized peak concentration and area-under-the-curve of BUP in Chinese were about half of Puerto Ricans, which was consistent with a higher clearance observed in Chinese (166 L / h vs. 270 L / h ). Furthermore, Monte Carlo simulations showed that an 8 mg three-times daily dose was the optimized regimen for Chinese OUD subjects. This regimen ensured that opioid receptor occupancy remained at a maximum (70%) in more than 95% of subjects, at the same time, with NLX plasma concentrations below the withdrawal reaction threshold (4.6  n g / m L ).

[Analysis of brain perfusion single-photon emission tomography images using an easy Zscore imaging system for early diagnosis of Alzheimer's disease]

OBJECTIVE

To analyze single-photon emission tomography (SPECT) images of cerebral blood flow perfusion using an easy Z-score imaging system (eZIS) and explore the value of SPECT and eZIS in early diagnosis of Alzheimer's disease (AD).

METHODS

We retrospectively analyzed the clinical data of 71 subjects undergoing brain perfusion SPECT examination in our department from September, 2018 to September, 2020 and identified 31 eligible subjects for this study. Among these subjects, according to the NIA-AA criteria (2011 edition), 12 were diagnosed with mild cognitive impairment due to AD (MCI) and 11 with AD dementia stage (AD); 8 elderly subjects were healthy without cognitive impairment (NC). All these subjects underwent brain perfusion SPECT, and eZIS-assisted analysis was used to obtain the index values (severity, range and ratio). The differences in the severity, extent and ratio among the 3 groups were compared, and the diagnostic efficacy of single and joint analysis of the 3 indexes for early AD was analyzed.

RESULTS

There was no significant difference in gender, age and education level among the 3 groups (P>0.05). Compared with those in NC group, the Mini Mental State Examination Scale (MMSE) scores were significantly lowered in AD group and MCI group; the MMSE score was significantly lower in AD group than in MCI group (P < 0.05). The patients with AD had significantly greater disease severity and extent than those with MCI group; the severity, range and ratio in both AD group and MCI group were significantly higher than those of NC group, but the ratio did not differ significantly between AD group and MCI group (P>0.05). In single index analysis, severity had the highest diagnostic performance (AUC=0.911) and sensitivity (87.0%); the diagnostic performance and sensitivity of joint analysis were better than those of single analysis, and joint analysis of range and ratio showed high diagnostic performance (AUC=0.948) and sensitivity (87.0%).

CONCLUSION

The analysis of brain perfusion SPECT using an eZIS program can be useful for early diagnosis of AD.

von Willebrand factor promotes platelet-induced metastasis of osteosarcoma through activation of the VWF-GPIb axis

•

Immunohistochemistry results directly show VWF is increased during tumor progression.

•

VWF is expressed as low molecular weight multimer in OS cell line SAOS2.

•

VWF promotes platelet-induced metastasis of OS through VWF-GPIb pathway.

von Willebrand factor (VWF) is exclusively expressed in endothelial cells (ECs) and megakaryocytes, which plays a crucial role in the initiation of arterial thrombosis. Recent studies have shown that VWF is also expressed in osteosarcoma (OS) cells and participates in adhesion of cancer cells to platelets, thus promoting metastasis of OS cells. However, it is unclear how OS cell-derived VWF-platelet interaction contributes to the metastasis of OS. We hypothesized that the interaction is mediated by the binding between VWF A1 and GPIbα of platelets, a molecular mechanism similar to that of thrombosis. The increased expression of VWF in SAOS2 cells may contribute to the enhancement of platelet adhesion through the VWF-GPIb pathway, which could promote the migration and invasion capacities of SAOS2 cells in vitro. Antibodies that block the pathway could significantly inhibit the platelet-induced metastasis of OS cells. Our results suggest a theoretical basis for the development of new anti-OS metastasis drugs, and further enrich the mechanism of OS metastasis.

Optimization of acquisition parameters for reduced-dose thoracic CT: A phantom study

PURPOSE

The purpose of this study was to analyze the impact of different options for reduced-dose computed tomography (CT) on image noise and visibility of pulmonary structures in order to define the best choice of parameters when performing ultra-low dose acquisitions of the chest in clinical routine.

MATERIALS AND METHODS

Using an anthropomorphic chest phantom, CT images were acquired at four defined low dose levels (computed tomography dose index [CTDI_vol]=0.15, 0.20, 0.30 and 0.40mGy), by changing tube voltage, pitch factor, or rotation time and adapting tube current to reach the predefined CTDI_vol-values. Images were reconstructed using two different levels of iteration (adaptive statistical iterative reconstruction [ASIR®]-v70% and ASIR®-v100%). Signal-to-noise ratio (SNR) as well as contrast-to-noise ratio (CNR) was calculated. Visibility of pulmonary structures (bronchi/vessels) were assessed by two readers on a 5-point-Likert scale.

RESULTS

Best visual image assessments and CNR/SNR were obtained with high tube voltage, while lowest scores were reached with lower pitch factor followed by high tube current. Protocols favoring lower pitch factor resulted in decreased visibility of bronchi/vessels, especially in the periphery. Decreasing radiation dose from 0.40 to 0.30mGy was not associated with a significant decrease in visual scores (P<0.05), however decreasing radiation dose from 0.30mGy to 0.15mGy was associated with a lower visibility of most of the evaluated structures (P<0.001). While image noise could be significantly reduced when ASIR®-v100% instead of ASIR®-v70% was used, the visibility-scores of pulmonary structures did not change significantly.

CONCLUSION

Favoring high tube voltage is the best option for reduced-dose protocols. A decrease of SNR and CNR does not necessarily go along with reduced visibility of pulmonary structures.

Measurement and analysis of maxillary anterior teeth color in the chinese population

Background

To measure the difference in the crown color of the maxillary anterior teeth in the Chinese population, to study its potential regularity, and to provide a reference for the colorimetry of oral anterior teeth restoration.

Material and Methods

Using VITA Easyshade Advance4.0 spectrophotometer (the colorimetric system is CIE-1976-L*a*b*), adult patients who were treated in Sanming Integrated Medicine Hospital, Fujian Province, China, from January 2022 to June 2022 160 patients (88 males, 72 females, aged 20-60 years) were used as the survey subjects, and the L*a*b* of 1/3 of the crowns of 6 anterior teeth (central incisors, lateral incisors, canines) were measured Value, statistical analysis was performed with SPSS 26.0 software.

Results

The mean L* values of maxillary central incisors, lateral incisors, and canines in the Chinese population were: (73.02±4.41), (69.96±4.70), (65.14±4.21); the mean a* values were: (-0.54±4.21) 0.35), (0.22±0.63), (1.40±0.62), and the mean values of b* were: (14.50±3.23), (18.60±3.94), (23.64±3.30). 1. There was no significant difference in L*a*b* value between left and right symmetrical teeth with the same name (P>0.05). 2. There was no statistical difference in the L*a*b* value between genders (P>0.05), 3. There was a statistical difference in L*a*b* value between different tooth positions (P< 0.05). 4. There were significant differences in L*a*b* values in different age groups (P< 0.05).

Conclusions

1. The color of the labial crown of maxillary anterior teeth in the Chinese population is related to different age groups and tooth positions but not gender. 2. In the Chinese population, the color of the maxillary anterior teeth on the labial side gradually decreased from the central incisor to the distal end of the dental arch while the chroma gradually increased. 3. With age increase, the L* and a* values of the upper central incisors, upper lateral incisors, and upper canines gradually decrease, and the b* value gradually increases. The teeth became darker, more yellow, and redder. 4. In the clinical colorimetry of the upper anterior teeth, the contralateral tooth with the same name is preferred. Suppose the tooth with the same name is missing at the same time. In that case, when using the adjacent teeth as a reference, the different brightness and chroma between the central incisors, lateral incisors, and canine teeth should be compared. Change trend to determine. 5. A uniform tooth color should not be selected for anterior restoration, and age should be considered when choosing a color for the patient. Key words:Upper anterior teeth, Crown color, CIE-1976-L*a*b*, spectrophotometric colorimeter.

Development of a population pharmacokinetic model of olanzapine for Chinese health volunteers and patients with schizophrenia

OBJECTIVE

Olanzapine is an atypical antipsychotic drug commonly used for the treatment of schizophrenia. However, there are still many complications associated with the use of olanzapine, and researchers continually strive to improve the handling of data from regular therapeutic drug monitoring (TDM). The objective of this study is to optimise the individualised treatment of olanzapine by establishing a population pharmacokinetics (PopPK) model in Chinese patients with schizophrenia.

METHODS

This study integrates an extensive collection of concentration data from healthy volunteers after a single dose and a less extensive collection of samples from patients undergoing TDM. A PopPK model was developed using non-linear mixed-effects modelling. Potential covariates, including the olanzapine manufacturer and patient gender and age, were assessed during model development. A total of 616 plasma concentration levels from 22 healthy male individuals in China and 458 concentration levels from 112 male and 122 female patients with schizophrenia undergoing TDM at 12 hospitals in China were included in the analysis. The concentration profile could be best described using a two-compartment model with first-order absorption and elimination.

RESULTS

The absorption rate (Ka) of olanzapine ranged from 2.85 h-1 to 5.39 h-1 for the different formulations. The typical absorption time delay was 0.877 hour. Body weight had a considerable effect on the apparent volume of the centre compartment and showed a power relationship.

CONCLUSIONS

A PopPK model of olanzapine in Chinese patients with schizophrenia was developed in this study. After determining the PK parameters of olanzapine, the results suggested that body weight exhibited a considerable impact effect on VC/F. The impact of subjects and formulations requires further study. The PopPK model established in this study is likely to provide some information for the individualised therapy of olanzapine.

TRIAL REGISTRATION NUMBER

ChiCTR-TRC-10000934; Results.

The In Vitro Effect of Ticlopidine on Fibrinogen and Factor VIII Binding to Human Platelets

The mode of action of the antiplatelet agent ticlopidine is not yet fully understood. Its multiple effects on platelet function include prolongation of the bleeding time, reduction in primary and secondary Waves of ADP-induced aggregation and inhibition of collagen and thrombin-induced aggregation. We have studied the in vitro effects of ticlopidine on fibrinogen binding induced by ADP and adrenaline as well as factor VIII/vWF binding induced by ristocetin.

125I-fibrinogen binding was measured in suspensions of freshly washed normal platelets stimulated by 10 μM ADP or 10 μM adrenaline. The binding of 125I-factor VIII/vWF in the presence of 1 mg/ml ristocetin was measured in both washed and paraformaldehyde-fixed platelets. Ticlopidine at final concentrations of 200, 100, 50 and 25 μM inhibited both ADP and adrenaline-induced fibrinogen binding in a dose-dependent manner. The mean % inhibition of ADP-induced fibrinogen binding was 82, 73, 42 and 32 respectively. The mean % inhibition of adrenaline induced fibrinogen binding was 86, 82, 60 and 35 respectively. In contrast, the factor VIII/vWF binding was unaffected by ticlopidine at all concentrations except at 200 μM using fresh platelets where a slight inhibition (19%) was observed.

These results suggest that ticlopidine either inhibits platelet activation and consequently fibrinogen binding, or inhibits the binding directly, presumably by having an effect on the specific configuration of the platelet membrane required for normal fibrinogen binding.

Clinical and molecular insights into Glanzmann's thrombasthenia in China

Glanzmann's thrombasthenia (GT) is a rare bleeding disorder characterized by spontaneous mucocutaneous bleeding. The disorder is caused by quantitative or qualitative defects in integrin αIIbβ3 (encoded by ITGA2B and ITGB3) on the platelet and is more common in consanguineous populations. However, the prevalence rate and clinical characteristics of GT in non-consanguineous populations have been unclear. We analyzed 97 patients from 93 families with GT in the Han population in China. This analysis showed lower consanguinity (18.3%) in Han patients than other ethnic populations in GT-prone countries. Compared with other ethnic populations, there was no significant difference in the distribution of GT types. Han females suffered more severe bleeding and had a poorer prognosis. We identified a total of 43 different ITGA2B and ITGB3 variants, including 25 previously unidentified, in 45 patients. These variants included 14 missense, 4 nonsense, 4 frameshift, and 3 splicing site variants. Patients with the same genotype generally manifested the same GT type but presented with different bleeding severities. This suggests that GT clinical phenotype does not solely depend on genotype. Our study provides an initial, yet important, clinical and molecular characterization of GT heterogeneity in China.

Exome sequencing identifies highly recurrent somatic GATA2 and CEBPA mutations in acute erythroid leukemia

Acute erythroid leukemia (AEL), characterized by a predominant erythroid proliferation, is a subtype of acute myelogenous leukemia. The genetic basis of AEL remains poorly defined. Through whole-exome sequencing, we identified high frequencies of mutations in CEBPA (32.7%), GATA2 (22.4%), NPM1 (15.5%), SETBP1 (12.1%) and U2AF1 (12.1%). Structure prediction analysis revealed that most of the GATA2 mutations were located at the DNA-binding N-terminal zinc-finger near the DNA-binding interface, suggesting that mutations could result in at least partial inactivation of GATA2 protein. On co-transfection of a GATA-responsive reporter construct together with plasmids expressing either GATA2 wild-type or GATA2 ZF1 mutants (P304H, L321P and R330X) in 293T cells, we found a reduced transcriptional activation in cells transfected with GATA2 mutants. To determine whether reduced GATA2 function is involved in leukemogenesis of AEL, we transfected 32D cells with GATA2 mutants and evaluated the impact of GATA2 mutations on erythroid differentiation. Our data revealed an increased expression of erythroid-related antigens Ter-119, β-globin and βh1-globin, as well as increased hemoglobin positivity in 32D cells transfected with GATA2 mutants compared with control cells. Our results suggest that the decline of GATA2 resulting from mutations contributes to the erythroid commitment, differentiation and the development of AEL.

The glycoprotein Ibalpha-von Willebrand factor interaction induces platelet apoptosis

BACKGROUND

The interaction of glycoprotein (GP) Ibalpha with von Willebrand factor (VWF) initiates platelet adhesion, and simultaneously triggers intracellular signaling cascades leading to platelet aggregation and thrombus formation. Some of the signaling events are similar to those occurring during apoptosis, however, it is still unclear whether platelet apoptosis is induced by the GPIbalpha-VWF interaction.

OBJECTIVES

To investigate whether the GPIbalpha-VWF interaction induces platelet apoptosis and the role of 14-3-3zeta in apoptotic signaling.

METHODS

Apoptotic events were assessed in platelets or Chinese hamster ovary (CHO) cells expressing wild-type (1b9) or mutant GPIb-IX interacting with VWF by flow cytometry or western blotting.

RESULTS

Ristocetin-induced GPIbalpha-VWF interaction elicited apoptotic events in platelets, including phosphatidylserine exposure, elevations of Bax and Bak, gelsolin cleavage, and depolarization of mitochondrial inner transmembrane potential. Apoptotic events were also elicited in platelets exposed to pathologic shear stresses in the presence of VWF; however, the shear-induced apoptosis was eliminated by the anti-GPIbalpha antibody AK2. Furthermore, apoptotic events occurred in 1b9 cells stimulated with VWF and ristocetin, but were significantly diminished in two CHO cell lines expressing mutant GPIb-IX with GPIbalpha truncated at residue 551 or a serine-to-alanine mutation at the 14-3-3zeta-binding site in GPIbalpha.

CONCLUSIONS

This study demonstrates that the GPIbalpha-VWF interaction induces apoptotic events in platelets, and that the association of 14-3-3zeta with the cytoplasmic domain of GPIbalpha is essential for apoptotic signaling. This finding may suggest a novel mechanism for platelet clearance or some thrombocytopenic diseases.

Two novel monoclonal antibodies to VWFA3 inhibit VWF-collagen and VWF-platelet interactions

BACKGROUND

The interaction of collagen-von Willebrand factor (VWF)-GPIb is essential for platelet adhesion, especially under high shear conditions. VWF, which acts as a bridge between platelets and exposed subendothelium, interacts with collagen through its A3 domain, which is a new target for the antithrombotic agent.

OBJECTIVE

To develop functional blockers that specifically inhibit VWF-dependent adhesion of platelets to collagen under high shear stress.

METHODS

To develop murine antihuman VWF A3 monoclonal antibodies (mAbs) by standard hybridoma technology, and characterize their abilities to block interactions between VWF A3 and collagen as well as platelet function.

RESULTS

Thirty anti-VWF-A3 mAbs were obtained. Among them, two mAbs, designated as SZ-123 and SZ-125, were found to inhibit VWF-collagen type III interaction. SZ-123 and SZ-125 inhibited the binding of purified human VWF (1.5 or 3 mug mL(-1)) to human placenta collagen type III (IC(50) = 0.07 +/- 0.02 and 0.15 +/- 0.03 mug mL(-1), respectively) or to calf skin collagen type III (IC(50) = 0.48 +/- 0.06 and 0.51 +/- 0.07 mug mL(-1), respectively) coated on plates. Under flow shear condition (1000 s(-1)), SZ-123 and SZ-125 inhibited platelet adhesion on human placenta collagen- or calf skin collagen-coated surfaces. Both mAbs also inhibited platelet aggregation induced by ristocetin, botrocetin or bovine plasma.

CONCLUSIONS

SZ-123 and SZ-125 inhibited VWF-collagen and VWF-platelet interactions.

ADAMTS-13 plasma level determination uncovers antigen absence in acquired thrombotic thrombocytopenic purpura and ethnic differences

BACKGROUND

The recently discovered plasma enzyme ADAMTS-13 cleaves the A2-domain of von Willebrand factor (VWF). A defective cleaving protease results in unusually large VWF multimers, which cause thrombotic thrombocytopenic purpura (TTP).

AIM

Analysis of the ADAMTS-13 antigen levels in TTP patients compared with normal donors.

METHODS

An antigen ELISA test was built, based on high affinity anti-ADAMTS-13 monoclonal antibodies, which were generated using genetic immunization.

RESULTS

Specificity of the ADAMTS-13 antigen test was confirmed, as (i) plasma from a patient with acquired TTP but presenting without inhibitor did not contain antigen and (ii) the binding of recombinant ADAMTS-13 was inhibited by increasing amounts of normal plasma. The assay is sensitive as it can detect antigen levels as low as 1.6% of normal. The concentration in normal pooled human plasma was determined (1.03 +/- 0.15 microg mL(-1)) and arbitrarily set to 1 U mL(-1). The antigen levels in congenital TTP samples (34 +/- 21 mU mL(-1), n = 2), as well as in samples from patients with acquired TTP (231 +/- 287 mU mL(-1), n = 11), were clearly reduced when compared with normal Caucasian donors (951 +/- 206 mU mL(-1), n = 16). Remarkably, normal Chinese donors have a significantly lower antigen titer (601 +/- 129 mU mL(-1), n = 15), when compared with normal Caucasians.

CONCLUSIONS

Our results show that acquired TTP patients suffer mainly from ADAMTS-13 antigen depletion, thereby indicating the importance of ADAMTS-13 antigen determination in diagnosis and patient follow-up.

Platelet-derived VWF-cleaving metalloprotease ADAMTS-13

The adhesion ligand von Willebrand factor (VWF) is synthesized and stored in vascular endothelial cells and megakaryocytes/platelets. As in endothelial cells, platelet VWF also contains ultra-large (UL) multimers that are hyperactive in aggregating platelets. ULVWF in platelet lysates of thrombin-stimulated platelets was only detected in the presence of EDTA, suggesting that ULVWF is cleaved by a divalent cation-dependent protease. A recent study shows that platelets contain the VWF-cleaving metalloprotease ADAMTS-13, but its activity remains unknown. In this study, we show that platelet lysates cleave endothelial cell-derived ULVWF under static and flow conditions. This activity is inhibited by EDTA and by an ADAMTS-13 antibody from the plasma of a patient with acquired TTP. ADAMTS-13 was detected in platelet lysates and on the platelet surface by four antibodies that bind to different domains of the metalloprotease. Expression of ADAMTS-13 on the platelet surface increases significantly upon platelet activation by the thrombin receptor-activating peptide, but not by ADP. These results demonstrate that platelets contain functionally active ADAMTS-13. This intrinsic activity may be physiologically important to prevent the sudden release of hyperactive ULVWF from platelets and serves as the second pool of ADAMTS-13 to encounter the increase in ULVWF release from endothelial cells.

Identification of six novel MYH9 mutations and genotype-phenotype relationships in autosomal dominant macrothrombocytopenia with leukocyte inclusions

The autosomal dominant macrothrombocytopenia with leukocyte inclusions, May-Hegglin anomaly (MHA), Sebastian syndrome (SBS), and Fechtner syndrome (FTNS), are rare platelet disorders characterized by a triad of giant platelets, thrombocytopenia, and characteristic Döhle body-like leukocyte inclusions. The locus for these disorders was previously mapped on chromosome 22q12.3-q13.2 and the disease gene was recently identified as MYH9, the gene encoding the nonmuscle myosin heavy chain-A. To elucidate the spectrum of MYH9 mutations responsible for the disorders and to investigate genotypephenotype correlation, we examined MYH9 mutations in an additional 11 families and 3 sporadic patients with the disorders from Japan. Korea, and China. All 14 patients had heterozygous MYH9 mutations, including three known mutations and six novel mutations (three missense and three deletion mutations). Two cases had Alport manifestations including deafness, nephritis, and cataracts and had R1165C and E1841K mutations, respectively. However, taken together with three previous reports, including ours, the data do not show clear phenotype-genotype relationships. Thus, MHA, SBS, and FTNS appear to represent a class of allelic disorders with variable phenotypic diversity.

The Sma I polymorphism in the von Willebrand factor gene associated with acute ischemic stroke

The von Willebrand factor (vWF) is a highly multimerized glycoprotein that promotes platelet adhesion and aggregation at a high shear rate, and also acts as a carrier of coagulation factor VIII. vWF has been identified as a risk factor for recurrent myocardial infarction in the general population. It has been reported that two polymorphisms of vWF gene promoter and the Thr789Ala polymorphism in vWF gene are associated with arterial thrombosis. The Sma I polymorphism is located in intron 2 of vWF gene. The relevance of this polymorphism to thrombotic disease was investigated by genotypic identification in two case-control studies: 107 patients with acute ischemic stroke, 49 patients with acute myocardial infarction (AMI), and 113 health controls age- and race-matched for each patient. Twenty-eight (26.2%) of the 107 patients with acute ischemic stroke, 8 (16.3%) of 49 patients with AMI, and 11 (9.7%) of 113 controls were found to be homozygous for CC genotype, respectively. The prevalence of the CC genotype in acute ischemic stroke was significantly higher than that of the normal controls (odds ratio [OR]=3.29, 95% confidence interval [CI]=1.54-7.01,.01>P>.001). However, the prevalence of the CC genotype in AMI was not significantly different from that of the normal controls (OR=1.81, 95% CI=0.68-4.82,.30>P>.20). Plasma vWF:Ag was also determined by enzyme-linked immunosorbent assay (ELISA) on the frozen plasma of 122 subjects. The mean plasma vWF:Ag levels of the controls, patients with acute ischemic stroke, and AMI were 0.468, 0.584, and 0.783 U/ml, respectively. The mean level of plasma vWF:Ag did not differ significantly between controls and patients with acute ischemic stroke (P=.195), but had significantly difference between controls and patients with AMI (P=.001). No association was found between the Sma I polymorphism and vWF plasma levels in controls, patients with acute ischemic stroke, or the AMI group (one-way ANOVA, P=.323, P=.315, P=.96). Results show that the Sma I polymorphism is strongly associated with increased risk of acute ischemic stroke, however, no association was observed between this polymorphism and AMI. This polymorphism of vWF may represent a newly identified risk factor for acute ischemic stroke in Chinese. Whether it is the real functional variant associated with acute ischemic stroke remains to be elucidated.

Spontaneous platelet aggregation with congenital giant platelet containing large granules and thick membrane

Inherited giant platelet disorders are a heterogeneous group of disorders. In the current study, a patient was reported with moderate bleeding tendency, giant platelets, and spontaneous platelet aggregation, which were not affected by the administration of aspirin or ticlopidine. The electron microscopy of platelets showed a black and thick plasma membrane with crystal-like fine hairs in the exterior coat and more large and variously shaped granules in the cytoplasm. The expression of glycoprotein (GP) Ib, GP IIb, and GP IIIa on platelet surface was normal, and no mutations in genes for GP Ib alpha, GP Ib beta, and GP IX were detected. These phenomena are so distinguishable from those of Mondreal platelet syndrome and other hereditary giant platelet disorders, that we propose that this patient probably has a novel platelet disorder, which has not yet been reported.

Detection of soluble urokinase receptor by immunoradiometric assay and its application in tumor patients

It has recently been found that tumor cells express large amounts of urokinase receptor (uPAR) on their surface and that the blood soluble uPAR (suPAR) level in cancer patients is increased. However, the significance of suPAR in tumor progression is still unclear. To investigate the significance of suPAR in evaluating clinical status of solid tumor patients, an immunoradiometric assay (IRMA) based on using two monoclonal antibodies (McAbs) to different epitopes of uPAR was established to determine the serum levels of suPAR in normal individuals and solid tumor patients. The detectable range of this suPAR IRMA was 1.95-500 microg/l. The affinity constant was 4.75x10(9) l/mol. The mean rate of recovery was 101.3%, and the mean coefficients of variation for intra- and interassay were 6.40+/-2.57% (mean+/-S.D., n = 11) and 10.48+/-2.65% (n = 5), respectively. The serum suPAR levels were 2.71+/-1.12 microg/l in 62 normal individuals, 3.71+/-1.69 microg/l in 30 patients with benign tumors, and 5.82+/-2.27 microg/l in 124 patients with malignant tumors. The serum suPAR levels of these two types of tumor patients were increased in comparison with that of normal individuals (P values less than.01 and.001). The extent of their increase in malignant tumors was much greater than in benign tumors (P < .001). The serum suPAR levels of patients with malignant tumors were correlated with tumor invasion, metastasis, and surgical intervention. Our data suggest that IRMA for suPAR could be a sensitive and specific assay and that the serum suPAR level would be a valuable index for evaluating the condition and prognosis of tumor patients in clinic.