Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Temporal Profiles of Symptom Scores After Palliative Radiotherapy for Bleeding Gastric Cancer With Adjustment for the Palliative Prognostic Index: An Exploratory Analysis of a Multicentre Prospective Observational Study (JROSG 17-3)

AIMS

Although palliative radiotherapy for gastric cancer may improve some symptoms, it may also have a negative impact due to its toxicity. We investigated whether symptoms improved after radiotherapy with adjustment for the Palliative Prognostic Index (PPI) considering that patients with limited survival tend to experience deterioration of symptoms.

MATERIALS AND METHODS

This study was an exploratory analysis of the Japanese Radiation Oncology Study Group study (JROSG 17-3). We assessed six symptom scores (nausea, anorexia, fatigue, shortness of breath, pain at the irradiated area and distress) at registration and 2, 4 and 8 weeks thereafter. We tested whether symptoms linearly improved after adjusting for the baseline PPI. Shared parameter models were used to adjust for potential bias in missing data.

RESULTS

The present study analysed all 55 patients enrolled in JROSG 17-3. With time from registration as the only explanatory variable in the model, a significant linear decrease was observed in shortness of breath, pain and distress (slopes, -0.26, -0.22 and -0.19, respectively). Given that the interaction terms (i.e. PPI × time) were not significantly associated with symptom scores in any of the six symptoms, only PPI was included as the main effect in the final multivariable models. After adjusting for the PPI, shortness of breath, pain and distress significantly improved (slope, -0.25, -0.19 and -0.17; P < 0.001, 0.002 and 0.047, respectively). An improvement in fatigue and distress was observed only in patients treated with a biologically effective dose ≤14.4 Gy.

CONCLUSION

Shortness of breath, pain and distress improved after radiotherapy. Moreover, a higher PPI was significantly associated with higher symptom scores at all time points, including baseline. In contrast, PPI did not seem to influence the improvement of these symptoms. Regardless of the expected survival, patients receiving radiotherapy for gastric cancer can expect an improvement in shortness of breath, pain and distress over 8 weeks. Multiple-fraction radiotherapy might hamper the improvement in fatigue and distress by its toxicity or treatment burden.

Purification and Some Chemical Properties of Thrombin-Like Enzyme from Trimeresurus Flavoviridis Venom

There has been no previous report indicating whether thrombin-like enzyme is contained in the venomof Trimeresurus flavoviridis whichhas the strongest toxic effect in the case of Habu bite. The presentstudy was undertaken to clarify the existence of thrombin-like enzyme in Trimeresurus flavoviridis venom. As a starting material, lyophilized crude venom of Trimeresurus flavoviridis was used, and ammonium sulphate fractionation, gel filtration using Sephadex G-25, Sephadex G-150 and arginine-Sepharose affinity chromatography were carried out to separate and purify a thrombin-like enzyme from the crude venom. The enzyme was purified to a 137-fold increase in specific activity and the purified preparation revealed a single band on SDS-PAGE. The molecular weight of the enzyme was estimated to be 65,000-70,000 daltons by means of SDS-PAGE and gel filtration, and its isoelectric point was pH 4.5-5.5. Furthermore, the optimal pH of the enzyme was in the range of pH 8.0 to 8.5. Some of the differences in enzymatic properties between this enzyme and bovine thrombin were studied. The snake enzyme could coagulate only rabbit plasma and convert only purified rabbit fibrinogen to fibrin gel. In addition, this thrombin-like enzyme released only fibrinopeptide A from purified rabbit fibrinogen and did not release fibrinopeptide B.

Investigations of water-extractability of As in excavated urban soils using sequential leaching tests: Effect of testing parameters

Excavated soils with low-level As contamination obtained from construction projects during city development have been of great concern in Japan. Water-extractable As represents the most easily mobilized and ecotoxicologically relevant fraction in the soil environment. In the present study, the water-extractability of As in excavated alkaline urban soils was assessed using sequential leaching tests (SLTs) with a focus on the effects of test parameters. In addition, the potentially water-leachable As over an extremely long period was assessed using the pollution potential leaching index (PPLI), from which one can estimate the number of extractions required to reduce the As in the cumulative leachates to below the Japanese environmental standard (10 μg L^-1). Total As concentrations varied from 6.75 to 79.4 mg kg^-1, and As was continuously detectable among replicate SLT experiments. The water-extractable As obtained in the first step of the SLT accounted for 0.41%-7.60% of total As (average: 2.36%), while the cumulative released As in the SLTs corresponded to 1.30%-21.6% of the total (average: 10.6%). The variability of the water-soluble fractions was sensitive to the test conditions. The shaking time at each SLT step had the largest effect on the As water-extractability; followed by sample storage, shaking speed and shaking interruption. A longer shaking time in the standard leaching test of excavated soils is suggested for regulatory purposes in Japan. The use of the PPLI concept for quick estimation of the potential As leachability from excavated soils was supported by the good reproducibility of PPLI results obtained from SLTs under different test parameters.

Pollution potential leaching index as a tool to assess water leaching risk of arsenic in excavated urban soils

Leaching of hazardous trace elements from excavated urban soils during construction of cities has received considerable attention in recent years in Japan. A new concept, the pollution potential leaching index (PPLI), was applied to assess the risk of arsenic (As) leaching from excavated soils. Sequential leaching tests (SLT) with two liquid-to-solid (L/S) ratios (10 and 20Lkg^-1) were conducted to determine the PPLI values, which represent the critical cumulative L/S ratios at which the average As concentrations in the cumulative leachates are reduced to critical values (10 or 5µgL^-1). Two models (a logarithmic function model and an empirical two-site first-order leaching model) were compared to estimate the PPLI values. The fractionations of As before and after SLT were extracted according to a five-step sequential extraction procedure. Ten alkaline excavated soils were obtained from different construction projects in Japan. Although their total As contents were low (from 6.75 to 79.4mgkg^-1), the As leaching was not negligible. Different L/S ratios at each step of the SLT had little influence on the cumulative As release or PPLI values. Experimentally determined PPLI values were in agreement with those from model estimations. A five-step SLT with an L/S of 10Lkg^-1 at each step, combined with a logarithmic function fitting was suggested for the easy estimation of PPLI. Results of the sequential extraction procedure showed that large portions of more labile As fractions (non-specifically and specifically sorbed fractions) were removed during long-term leaching and so were small, but non-negligible, portions of strongly bound As fractions.

Potential for leaching of arsenic from excavated rock after different drying treatments

Leaching of arsenic (As) from excavated rock subjected to different drying methods is compared using sequential leaching tests and rapid small-scale column tests combined with a sequential extraction procedure. Although the total As content in the rock was low (8.81 mg kg(-1)), its resulting concentration in the leachate when leached at a liquid-to-solid ratio of 10 L kg(-1) exceeded the environmental standard (10 μg L(-1)). As existed mainly in dissolved forms in the leachates. All of the drying procedures applied in this study increased the leaching of As, with freeze-drying leading to the largest increase. Water extraction of As using the two tests showed different leaching behaviors as a function of the liquid-to-solid ratio, and achieved average extractions of up to 35.7% and 25.8% total As, respectively. Dissolution of As from the mineral surfaces and subsequent re-adsorption controlled the short-term release of As; dissolution of Fe, Al, and dissolved organic carbon played important roles in long-term As leaching. Results of the sequential extraction procedure showed that use of 0.05 M (NH4)2SO4 underestimates the readily soluble As. Long-term water extraction removed almost all of the non-specifically sorbed As and most of the specifically sorbed As. The concept of pollution potential indices, which are easily determined by the sequential leaching test, is proposed in this study and is considered for possible use in assessing efficacy of treatment of excavated rocks.

Plasma CD147 reflects histological features in patients with lupus nephritis

OBJECTIVE

A glycosylated transmembrane protein, CD147, has been implicated in regulating lymphocyte responsiveness and leukocyte recruitment. As lupus nephritis (LN) often follows a relapsing-remitting disease course, accurate understanding of the disease activity would be extremely helpful in improving prognosis. Unfortunately, neither clinical nor serological data can accurately reflect the histological features of LN. The present study investigated whether CD147 can accurately predict pathological features of LN.

METHODS

Plasma and spot urine samples were collected from 64 patients who underwent renal biopsy between 2008 and 2011. Disease activity for LN tissues was evaluated using the biopsy activity index, and compared to levels of biomarkers including CD147.

RESULTS

In LN tissues, CD147 induction was striking in injured glomeruli and infiltrating inflammatory cells, but not in damaged tubules representing atrophy. Plasma CD147 levels accurately reflected the histological disease activity. However, prediction using a single molecule would be quite difficult because of the complex pathogenesis of LN. The diagnostic accuracy of multiplex parameters indicated that the combination including plasma CD147 might yield excellent diagnostic abilities for guiding ideal LN therapy.

CONCLUSION

Plasma CD147 levels might offer useful insights into disease activity as a crucial biomarker in patients with LN.

Accurate determination of patient-specific boundary conditions in computational vascular hemodynamics using 3D cine phase-contrast MRI

In the patient-specific vascular CFD, determination of the inlet and outlet boundary conditions (BCs) is an important issue for a valid diagnosis. The 3D cine phase-contrast MRI (4D Flow) velocimetry is promising for this issue; yet, its measured velocities contain relatively large error and are not admissible as the BCs without any correction. This paper proposes a novel correction method for determining the BCs accurately using the 4D Flow velocimetry. First, we reveal that the error of the velocity measured by the 4D Flow at each measurement voxel is large but is distributed symmetrically. Secondly, our method pays attention to the incompressibility of the blood and the fact that the volume flow rate (VFR) in each vessel is constant on any cross sections. We reveal that the average of the cross-sectional VFRs integrated from many measurement voxel in each vessel is accurate despite the large error. Finally, we propose the novel correction method, which applies a smoothing to the measured velocities on each inlet or outlet boundary with a low-pass filter and then corrects them with the VFR. The results of the several phantom studies are presented to validate the accuracy of our method. A demonstrative analysis for an actual aneurysm is also presented to show the feasibility and effectiveness of our method.

Minimally invasive removal of a recurrent lumbar herniated nucleus pulposus by the small incised microendoscopic discectomy interlaminar approach

In this report, we introduce two cases of recurrent herniated nucleus pulposus (HNP) at L5-S1 that were successfully removed using the small incised microendoscopic discectomy (sMED) technique, proposed by Dezawa and Sairyo in 2011. sMED was performed via the interlaminar approach with a percutaneous endoscope. The patients had previously underdone microendoscopic discectomy for HNP. For the recurrent HNP, the sMED interlaminar approach was selected because the HNP occurred at the level of L5-S1; the percutaneous endoscopic transforaminal approach was not possible for anatomical reasons. To perform sMED via the interlaminar approach, we employed new, specially made devices to enable us to use this technique. In conclusion, sMED is the most minimally invasive approach available for HNP, and its limitations have been gradually eliminated with the introduction specially made devices. In the near future, percutaneous endoscopic surgery could be the gold standard for minimally invasive disc surgery.

Endoscopic removal of herniated nucleus pulposus migrated dorsally to the dural sac

A herniated nucleus pulposus (HNP) migrated dorsally to the dural sac is a rare condition. Here, we present a case, in which the HNP was removed with minimally invasive spinal endoscopy. A 54-year-old man presented complaining of left leg pain and paresis. Neurologic findings and an MRI suggested an epidural tumor or a dorsally migrated HNP compressing the S1 nerve root and dural sac. With a spinal endoscope, careful laminotomy of caudal L5 and cranial S1 was made. En bloc flavectomy exposed a mass covered with a thin capsule. The mass was identified as a dorsally migrated HNP. After complete HNP fragment removal, the dural sac and S1 nerve root were decompressed. Immediately postoperative, the leg pain subsided and motor function normalized, although the patient complained of numbness at the S1 dermatome area. In summary, a large HNP that had migrated dorsally to the dural sac was successfully removed endoscopically.

Polymer parallel optical waveguide with graded-index rectangular cores and its dispersion analysis

A low-loss and high-bandwidth polymer parallel optical waveguide with graded-index (GI) rectangular cores is fabricated for high-speed and high-dense optical interconnections. We demonstrate that the near-parabolic index profile formed in the rectangular-shaped core GI waveguide exhibits superior properties similar to those of GI circular core waveguides we previously reported. In particular, we focus on the modal dispersion in the GI polymer waveguides with rectangular cores by showing experimental results. In this paper, the GI rectangular cores are fabricated using the preform method. However, conventional photo-lithography and imprinting processes are viable to fabricate a similar waveguiding structure, by which fabrication of a printed circuit board embedding this waveguide would become feasible.

Visualization of hemodynamics in a silicon aneurysm model using time-resolved, 3D, phase-contrast MRI

We performed time-resolved 3D phase-contrast MR imaging by using a 1.5T MR scanner to visualize hemodynamics in a silicon vascular model with a middle cerebral aneurysm. We ran an aqueous solution of glycerol as a flowing fluid with a pulsatile pump. Time-resolved images of 3D streamlines and 2D velocity vector fields clearly demonstrated that the aneurysm had 3D complex vortex flows within it during systolic phase. This technique provided us with time-resolved 3D hemodynamic information about the intracranial aneurysm.

Aberrant expression of β- and γ-catenin is an independent prognostic marker in oral squamous cell carcinoma

Alteration in expression of E-cadherin and catenins is associated with loss of differentiation, acquisition of an invasive phenotype and poor clinical outcome in many types of cancer. To identify molecular prognostic markers, membrane expression levels of E-cadherin, and alpha-, beta- and gamma-catenin in biopsy samples (n=135) of oral squamous cell carcinoma (OSCC) were evaluated immunohistochemically in relation to preoperative tumour-related features, clinical course and prognostic value, and were found to be significantly correlated with an endophytic growth pattern and pathologically proved lymph-node metastasis. Alteration of expression of E-cadherin, and alpha-, beta- and gamma-catenin was also significantly correlated with poor disease-specific 5-year survival (P=0.0096, 0.0434, 0.0005 and 0.0005, respectively). Multivariate Cox proportional hazard regression analysis showed that alteration of beta- and gamma-catenin expression was a significantly independent prognostic parameter for survival (P=0.0112 and 0.0088, respectively), as was the case with endophytic growth pattern and advanced N-category. These results indicate that patients with OSCC and absent or reduced membrane expression of beta- and gamma-catenin should be considered a high-risk group for regional lymph-node metastasis and poor prognosis.

Isolation of bound thrombin consisting of thrombin and fibrin N-terminal fragment from clot lysate

It has been reported that thrombin is liberated from fibrin clots by the action of fibrinolytic enzymes. It has also been reported that the liberated thrombin complexes with fibrin fragment E or (DD)E, which are denoted as bound thrombin. However, bound thrombin has not been isolated from clot lysate, and the structural characteristics of isolated bound thrombin have not been specified. In this study, we attempted to isolate the bound thrombin from clot lysate and to clarify its structural features. Rabbit fibrinogen was clotted with bovine thrombin, and clot lysate was prepared with urokinase. The bound thrombin was isolated from clot lysate by serial chromatography using a Sepharose 4B column immobilizing an anti-bovine thrombin antibody and a Sepharose 4B column immobilizing an anti-rabbit fibrinogen antibody. SDS-PAGE under unreduced conditions demonstrated that there were two different protein bands in the isolated bound thrombin. On a C4 reverse-phase HPLC, the bound thrombin from clot lysate was resolved by 4 M urea into alpha-thrombin and a fibrin fragment, the N-terminal regions of which were identified as alpha-, beta- and gamma-chains. Thus, in the bound thrombin, thrombin molecule would bind to rabbit fibrin fragment consisting of N-terminal central domain.

Bound thrombin-induced upregulation of myosin heavy chain isoform, SMemb messenger RNA expression in cultured rabbit vascular smooth muscle cells

To investigate whether bound thrombin can induce modulation of SMemb expression in vascular smooth muscle (VSM) cells, messenger RNA (mRNA) expression was measured by in situ hybridization (ISH) and reverse transcription-polymerase chain reaction (RT-PCR) in cultured rabbit aortic VSM cells. To test the concentration- and time-dependent effect of bound thrombin on the expression of SMemb, confluent VSM cells were incubated for 48 h in 10% FBS-DMEM containing 0, 3, 10 and 30 units/ml of bound thrombin. In addition, the confluent VSM cells were incubated for 6, 12, 24 and 48 h in 10% FBS-DMEM containing 10 units/ml of bound thrombin. Consequently, bound thrombin significantly increased SMemb mRNA in a concentration- and time-dependent manner. When compared with the effect of rabbit fibrinogen (10 microg/ml) and native thrombin (10 units/ml), SMemb mRNA was significantly increased by bound thrombin and was slightly increased by native thrombin, but not by fibrinogen. Other myosin heavy chain (MHC) isoform (SM1 and SM2) mRNA expressions were not changed by fibrinogen, native thrombin or bound thrombin. ISH revealed that there was no significant difference in the expression of MHC mRNAs among fibrinogen, native thrombin or bound thrombin. Western blot analysis demonstrated that the SMemb protein level was significantly increased by 2.5-fold by bound thrombin. When the clot-forming activities in cultured medium containing native thrombin or bound thrombin were measured from 0.5 to 48 h, the activity of bound thrombin declined more slowly than that of native thrombin. In conclusion, bound thrombin could upregulate the expression of SMemb mRNA and protein in cultured VSM cells and the activity of bound thrombin was maintained for longer than that of native thrombin in culture medium.

The nucleotide sequence of dinitrophenyl-specific IgE and Fc(epsilon)RI alpha-subunit obtained from FE-3 hybridoma cells

FE-3 cells were established by Hanashiro et al. by hybridizing mouse myeloma cells (Sp2/0-Ag14/SF) with rat spleen cells that were freshly isolated from Brown-Norway rats sensitized with DNP-As. FE-3 cells can constitutively secrete IgE without stimulation by cytokines. Our preliminary experiments demonstrated that the IgE secretion was decreased at 3 days after start of culture and the addition of exogenous IgE into culture media depressed the secretion of IgE. Thus, we hypothesized that the IgE production in FE-3 cells may be regulated by a signal transduction through the binding of IgE to its high affinity receptor (Fc(epsilon)RI) or to an IgE binding protein on the cell surface. In this study, we aimed to identify the nucleotide sequence of IgE FE-3 and compared with those of mouse IgE and IgE IR162 to find a structural heterogeneity in the Fc region of IgE FE-3. We also tested if the mRNA of Fc(epsilon)RI was expressed in FE-3 cells using the reverse transcriptase-polymerase chain reaction (RT-PCR) method with the combination of sequencing analysis. Consequently, the cDNA sequence of IgE FE-3 was identical to that of the CH3 and CH4 domains in the epsilon-chain of rat IgE IR162, whereas the cDNA of Fc(epsilon)RI was identical to that of mouse, suggesting that the genes of IgE FE-3 and Fc(epsilon)RI was derived from that of rat spleen cells and mouse myeloma cells, respectively.

A monoclonal antibody against bovine thrombin reacting to the C-terminal side of thrombin

We succeeded in producing a monoclonal antibody (MAb) against bovine thrombin. The MAb belonged to mouse IgG(1), and its light chain consisted of kappa-chain. The MAb reacted with bovine and human thrombins, which were coated by coupling to poly-lysine-coated wells with glutaraldehyde, but did not react with the thrombin-like enzyme, habutobin. Furthermore, the MAb did not react with thrombin which was coated to plates without poly-lysine and glutaraldehyde. The concentration of thrombin in ovalbumin solution (10 mg/mL) could be measured by means of the enzyme-linked immunosorbent assay (ELISA) double sandwich method using the MAb and polyclonal antibody. Thrombin added to defibrinated plasma could not be detected by means of the ELISA double sandwich method using the present MAb, and this may be due to the AT-III activity in the defibrinated plasma. Postclotting thrombin could be detected by means of the ELISA-double sandwich method using the MAb. It is suggested, from the results of our experiments, that the MAb obtained reacted in a limited fashion to the C-terminal of bovine thrombin.

Expression of p16, nm23-H1, E-cadherin, and CD44 gene products and their significance in nasopharyngeal carcinoma

OBJECTIVE

The present study was aimed to determine whether p16/MTS1, nm23-H1, E-cadherin, and CD44 proteins were expressed in nasopharyngeal carcinoma (NPC) and whether those expressions were pathologically significant in the progress of NPC.

METHOD

We examined non-cancerous nasopharyngeal mucosa (20 cases) and NPC (80 cases) using immunohistochemistry with six different types of monoclonal antibodies against p16, nm23-H1, E-cadherin, CD44H, CD44v3, and CD44v6 proteins.

RESULTS

The results showed that 1) the rates of positive p16 protein expression and of preserved E-cadherin protein expression in NPC were significantly lower than those in non-cancerous tissue (P <.01); 2) no significant difference in the rate of positive expression of nm23-H1, CD44H, CD44v3, and CD44v6 proteins were observed between non-cancerous nasopharyngeal mucosa and NPC; 3) no significant difference in the expression of those proteins were found by respective correlation analyses of sex, stage, and size of primary tumor in NPC; and 4) no significant difference in the rates of positive expression of CD44H, CD44v3, and CD44v6 proteins were observed in NPC between with and without lymph node metastasis, indicating that those gene products did not correlate with lymph node metastasis in NPC. However, there were inverse correlations between the expression of p16, nm23-H1, or E-cadherin protein and lymph node metastasis (P <.05), indicating that the expression of p16, nm23-H1, and E-cadherin gene were related to the carcinogenesis and tumor progression of NPC.

CONCLUSION

Detecting the expressions of those gene products may provide clinically valuable information for therapeutic strategy and for predicting the prognosis of patients with NPC.

Analysis of IgE turnover in non-sensitized and sensitized rats

BACKGROUND

Although the levels of immunoglobulin E (IgE) in the circulating blood are often elevated in patients with allergic diseases, such levels cannot always be considered as pathognomonic signs of allergy. The induction of allergic reactions in the tissue was inferred to be related to the amount of IgE passing through the vascular wall.

AIMS

We attempted to clarify which compartment, the intravascular or extravascular, plays an important role in the regulation of the turnover of rat IgE.

METHODS

The level of DNP-specific rat IgE in the serum was estimated by IgE-capture enzyme-linked immunosorbent assay, and the turnover of IgE was analyzed from its pharmacokinetic parameters.

RESULTS

The transfer rate constants from the central to tissue compartment (Kct) were larger than those from the tissue to central compartment (Ktc) irrespective of the sensitized state. The value of the distribution volume of the tissue compartment (Vt) was larger than that of the distribution volume of the central compartment (Vc) irrespective of the sensitized state.

CONCLUSIONS

These Findings suggest that the short half-life of rat IgE in the circulation could be attributable to the distribution of IgE from the intravascular to the extravascular compartment.

Hematological studies on DIC-like findings observed in patients with snakebite in south China

To clarify the characteristics of the hematological disturbances evoked by snakebite, we measured the antithrombin III (AT-III) activity, alpha2-plasmin inhibitor (alpha2-PI) activity, fibrinogen concentration (Fg) and level of fibrin degradation products (FDP) in 21 patients envenomed by several snakes in south China between August 1998 and October 1999. The hematological changes observed were as follows: the mean activities of AT-III were decreased in patients bitten by Ophiophagus hannah (Oh.), Bungarus fasciatus (Bf.), Hydrophis cyanocinctus (Hc.), Rhabdophis subminiatus (Rs.), and Trimeresurus stejnegeri (Ts.), while those of alpha2-PI were decreased in all patients in the present study; Fg was not detectable in the case of Rs. bite, and the Fg concentration after Ts., Oh., Hc. and Bf. bites also decreased markedly thereby increasing the mean levels of FDP in all patients. It thus appeared that DIC-like syndrome was caused in patients envenomed by snakebite. In the present study, we found that patients who were bitten by Rs., which is still being classified as a non-venomous snake, exhibited complete defibrinogenation and severe hemorrhage without any evidence of severe multiple organ damage. We also found that patients with Ts. bite showed marked hemostatic disturbance without severe multiple organ damage. It is considered that such a discrepancy between the hematological findings and clinical symptoms could be a characteristic phenomenon of the DIC-like syndrome induced by snakebite, especially by Rs. and Ts. bites.

Nanosized Ni/SiO2 catalyst prepared by homogeneous precipitation in wet silica gel

A Ni/SiO2 catalyst was prepared by homogeneous precipitation of nickel hydroxide in a sol-gel-derived wet silica gel. The preparation process consists of two successive steps: gelation of silica in the presence of nickel nitrate and urea at 50 degrees C, followed by aging at higher temperature, typically at 80 degrees C, to decompose the urea. The decomposition of urea increases the pH of the solution in the wet gel, leading to the concurrence of structural rearrangement of silica gel and deposition of nickel species. As a result, the structure of the silica changes from a ramified polymeric network into particle aggregates that entrap the nickel cations in the particles. The resulting Ni/SiO2 contains large mesopores that have high thermal stability up to 1000 degrees C and highly dispersed Ni metal particles with typical crystallite size of 4 nm even at high Ni content at 20 wt%.

An autopsy case of the schizophrenic 32 years after lobotomy

An autopsy case is reported here of a 69-year-old patient with schizophrenia, who was known retrospectively to have had a prefrontal lobotomy 32 years previously. The patient was diagnosed as schizophrenic at the age of 24 and the lobotomy was undertaken 13 years later. The patient was recently found outside in a dehydrated condition and admitted to a general hospital, where he died of respiratory failure. Bilateral cystic lesions were found in the deep white matter of the frontal lobe. The cyst walls consisted of glial fibrous tissues, and severe demyelination with axonal destruction was diffusely observed in the white matter of the frontal lobe. In the thinner frontal cortex without arcuate fibers (U fibers) close to the cavities, cytoarchitectural abnormalities were observed. In the thalamic nuclei marked retrograde degeneration and astrocytic gliosis were observed. The detailed neuropathological findings of a lobotomized schizophrenic brain are reported here. It is proposed that one should be reminded of a lobotomized brain if bilateral cysts are found.

Lack of tyrosine protein kinase regulation of L-type Ca2+ channel current in transfected cells stably expressing alpha1C-b Subunit

Tyrosine protein kinase (Tyr-PK) regulation of L-type Ca2+ channel (CaL) current was studied in COS-7 cells expressing vascular smooth muscle-type alpha1C-b with no auxiliary subunit by using a whole-cell voltage clamp. The averaged peak amplitude of CaL currents was -0.33 +/- 0.03 at holding potential of -60 mV. Na(3)VO(4), genistein and phosphorylated p60(c-src) peptide had no effect on the current. Thus the alpha1C-b subunit may not be involved in Tyr-PK regulation of CaL current.

The relationship between microvessel density, the expression of vascular endothelial growth factor (VEGF), and the extension of nasopharyngeal carcinoma

OBJECTIVE

The present study was aimed at clarifying whether the microvessel density (MVD) and the expression of vascular endothelial growth factor (VEGF) were related to the degree of local invasion and metastasis in nasopharyngeal carcinoma (NPC).

STUDY DESIGN

We measured the MVD and examined whether VEGF was expressed in NPC tissue using histological study combined with immunohistochemistry.

METHODS

MVD and VEGF expression was measured in 73 specimens of NPC, 15 benign tumors of nasopharyngeal region, and 20 nasopharyngeal tissue without tumor. MVD and VEGF expression in NPC was compared between a metastasis group (49 specimens) and a non-metastasis group (24 specimens).

RESULTS

Both MVD and VEGF expression were markedly increased in NPC tissue as compared with those in benign tumors of nasopharyngeal region. Both MVD and VEGF expression in NPC tissue with metastasis were statistically significantly increased as compared with those in NPC without metastasis. Therefore, the invasion and metastasis of NPC cells were closely related to MVD and the expression of VEGF in NPC tissue.

CONCLUSION

The metastatic potency of NPC tissue and the prognosis of the patients with NPC can be estimated by measuring MVD and the expression of VEGF in NPC tissue. Drugs that have inhibitory actions on angiogenesis could be useful to prevent metastasis of NPC cells in the patients.

Enhanced phospholipase C activity in the cultured skin fibroblast obtained from patients with coronary spastic angina: possible role for enhanced vasoconstrictor response

OBJECTIVES

We measured phospholipase C (PLC) activity in the cultured skin fibroblasts obtained from patients with and without coronary spasm and examined its correlation with coronary artery vasomotility.

BACKGROUND

Coronary artery vasomotility is enhanced in coronary spastic angina (CSA), but no information is available for the intracellular signaling. In spontaneously hypertensive rats, PLC activity in the skin fibroblasts has been shown to be enhanced.

METHODS

Skin fibroblasts obtained from 24 patients with CSA-14 with organic coronary artery disease (CAD) and 12 control subjects--were cultured by the explant method. Activity of PLC was determined by incubating the membrane fraction with 3H-phosphatidyl inositol bisphosphate and by quantifying 3H-inositol trisphosphate. In patients with CSA and control subjects, the relations between PLC activity and coronary artery basal tone and constrictor response to intracoronary acetylcholine (ACh) were examined.

RESULTS

Activity of PLC (pmol/protein [mg] per min) was 1.74+/-0.19 in patients with CSA; 0.90+/-0.12 in patients with CAD; and 0.65+/-0.07 in control subjects (p<0.001, patients with CSA vs. patients with CAD and control subjects; p = NS, patients with CAD vs. control subjects). According to the Lineweaver-Burk plot, Michaelis constant (micromol/liter) of PLC was 28+/-4 in patients with CSA; 49+/-14 in patients with CAD; and 56+/-10 in control subjects (p<0.05, patients with CSA vs. control subjects), whereas the maximal velocity was not different between the three groups. There were significant positive correlations between PLC activity and both basal tone (p = 0.0108) and response to ACh (p = 0.0053). Western blot analysis using membrane fraction demonstrated that 89% of PLC isoenzymes detected was of the delta1 isoform.

CONCLUSIONS

Because the PLC activity measured was genetically defined and was positively correlated with coronary artery vasomotility, enhanced PLC activity may be involved in the pathogenesis of coronary spasm.

Hemostatic disturbances observed in patients with snakebite in south China

To investigate the hematological disorders after snakebite, we measured the maximum platelet aggregation rate (MAR), antithrombin III (AT-III) activity, alpha(2)-plasmin inhibitor (alpha(2)-PI) activity, concentration of fibrinogen (Fg) and fibrin degradation products (FDP) in 25 samples from 17 patients with snakebite in south China. The results obtained in the patients before application of antivenom and patients with Ophiophagus hannah (Oh.) bite were as follows: (1) the mean MAR values were significantly decreased in the case of the snakebites from Vipera russellii (Vr.) and Trimeresurus mucrosquamatus (Tm.); (2) the mean activities of AT-III were decreased in all patients in the present study; 3) the mean activities of alpha(2)-PI were significantly decreased in patients bitten by Deinagkistrodon acutus (Da.), Agkistrodon halys (Ah.), Vr., Trimeresurus stejnegeri (Ts.), Tm. and Naja naja atra (Nn.); (4) the mean concentrations of Fg were markedly decreased in patients bitten by Da., Ah., Vr., Ts. and Tm.; and (5) the mean levels of FDP were significantly increased in cases of Da., Vr. and Ts. bite, but not in Ah., Tm., Nn. and Oh. bite. The results of the present study indicate that disorders of platelet aggregation and the coagulation-fibrinolysis system are liable to occur in patients with snakebite from Da., Ah., Vr., Ts., Tm. and Nn. Furthermore, it appeared that disseminated intravascular coagulation (DIC) was evoked in some patients. Specific antivenom was found to be useful for improving the hemostatic disturbances after snakebite from Ah. and Nn.

Radical scavenging properties of novel benzopyran derivatives, TA248 and TA276, and effects of the compounds on ischemic/reperfused myocardium in dogs

Characteristics of novel benzopyran derivatives, TA248 and TA276, and their effects on myocardial contraction in ischemic/reperfused hearts in dogs were examined. TA248 and TA276 inhibited NADPH-dependent lipid peroxidation induced by Fe(3+) in the rat brain homogenate. Both compounds reduced *O(2-) produced by xanthine-xanthine oxidase system in a dose-dependent manner. TA276 scavenged.OH generated by Fenton reaction in a dose-dependent manner. TA248 also inhibited the.OH production, but the effect was neither complete nor dose dependent. Myocardial contraction was assessed as segment shortening of the left ventricular wall in pentobarbital-anesthetized open-chest dogs. The segment shortening was decreased by the left anterior descending coronary artery ligation (ischemia) and returned by release of the ligated artery (reperfusion). The segment shortening did not recover fully during reperfusion. Either TA248 or TA276 injected 10 min before ischemia improved the recovery of myocardial contraction during reperfusion. Both compounds preserved the level of ATP in the 60-min reperfused myocardium. However, the level of lipid peroxides was not changed by TA248 and TA276. TA248 and TA276 may protect myocardium against ischemic/reperfusion insult, partly because of their free radical scavenging activity, but no significant change in myocardial lipid peroxide level was observed.

Actin filament disruption inhibits L-type Ca(2+) channel current in cultured vascular smooth muscle cells

To clarify interactions between the cytoskeleton and activity of L-type Ca(2+) (Ca(L)) channels in vascular smooth muscle (VSM) cells, we investigated the effect of disruption of actin filaments and microtubules on the L-type Ca(2+) current [I(Ba(L))] of cultured VSM cells (A7r5 cell line) using whole cell voltage clamp. The cells were exposed to each disrupter for 1 h and then examined electrophysiologically and morphologically. Results of immunostaining using anti-alpha-actin and anti-alpha-tubulin antibodies showed that colchicine disrupted both actin filaments and microtubules, cytochalasin D disrupted only actin filaments, and nocodazole disrupted only microtubules. I(Ba(L)) was greatly reduced in cells that were exposed to colchicine or cytochalasin D but not to nocodazole. Colchicine even inhibited I(Ba(L)) by about 40% when the actin filaments were stabilized by phalloidin or when the cells were treated with phalloidin plus taxol to stabilize both cytoskeletal components. These results suggest that colchicine must also cause some inhibition of I(Ba(L)) due to another unknown mechanism, e.g., a direct block of Ca(L) channels. In summary, actin filament disruption of VSM cells inhibits Ca(L) channel activity, whereas disrupting the microtubules does not.

Habutobin recognizes Thr(7) in the sequence of fibrinopeptide A of rabbit fibrinogen

Habutobin, a thrombin-like enzyme from Trimeresurus flavoviridis venom, cleaves only the Arg(16)-Gly(17) bond in the rabbit Aalpha chain and releases fibrinopeptide A (FPA). To investigate the role of amino acid residues in the rabbit FPA sequence upon habutobin action, we examined the inhibitory effects of FPA and peptides containing partial sequences of FPA on the habutobin action. Fibrinopeptides from rabbit, human, bovine and dog were isolated and rabbit FPA was fragmented using dilute HCl. Rabbit FPA inhibited the action of habutobin although FPA from human, bovine and dog did not. Among the fragments of rabbit FPA, a heptapeptide Aalpha 3-9, the N-terminal region of rabbit FPA, competitively inhibited the release of FPA by habutobin, whereas the C-terminal hexapeptide of FPA (Aalpha 11-16) exerted no effect on the habutobin action. Synthetic tripeptides Ser-Thr-Phe corresponding to Aalpha 6-8 and Ala-Thr-Phe also inhibited the habutobin action, but Ser-Asp-Phe and Ala-Thr-Gly did not. It is concluded that habutobin would recognize the region around Thr(7)-Phe(8) in the sequence of rabbit FPA (Aalpha 1-16) prior to the cleavage of the Arg(16)-Gly(17) bond.

Molecular cloning of three homoeologous cDNAs encoding orthologs of the maize KNOTTED1 homeobox protein from young spikes of hexaploid wheat

The plant knotted1 (kn1)-like homeobox genes are known to play important roles in the maintenance of shoot apical meristem (SAM), determination of cell fate and differentiation of vegetative tissues. To study structural diversity of the three homologous loci encoding a KN1-like homeobox protein in the hexaploid wheat genome, we isolated clones from a cDNA library of young spikes of Japanese common wheat cultivar 'Norin 26'. Three different but highly homologous cDNAs were isolated and their sequences were determined. The mean homology of the deduced amino acid sequences was 96% as compared to the barley ortholog KNOX3. The wheat kn1-like homeobox proteins named WKNOX1 are encoded by a single set of homologous genes on the homologous group 4 chromosomes in the three component genomes of common wheat, i.e. 4A, 4B and 4D. The nucleotide sequence data and the Southern blot pattern suggested that the three homologous loci of wknox1 genes are highly conserved through polyploid evolution of wheat. They were expressed in SAM-containing shoots and young spikes but not in developed leaves, glumes and lemmas and callus tissues. The ectopic expression of the wknox1 was observed in lemma of wheat Hooded (Hd) mutants. The result suggested that the Hd gene is a dominant allele of the wknox1 locus on chromosome 4A.

Long-term outcome of chronic hepatitis B in adolescents or young adults in follow-up from childhood

BACKGROUND

It has not yet been defined whether children with chronic hepatitis B are likely to develop severe liver disease in the future. The purpose of this study was to evaluate the evolution of chronic hepatitis B acquired in childhood.

METHOD

Fifty-two children in the age range of 0 to 15 years who were positive for hepatitis B surface antigen and hepatitis B e antigen in serum for at least 6 months were enrolled in this study. In the majority of the 52 children, hepatitis B virus infection was acquired by perinatal transmission. All 52 showed abnormal liver function test findings for more than 6 months before enrollment, and the subjects were followed up longitudinally for 3 to 22 years (mean, 11 years). They are now more than 15 years of age (15-27 years old).

RESULTS

During the follow-up period, 26 (50%) children had spontaneous seroconversion to anti-hepatitis B e. Serum levels of alanine aminotransferase normalized in these 26 children. In one child of these children, hepatocellular carcinoma developed at the age of 21 years, 16 years after seroconversion, although his liver function profiles remained normal. The other 26 children remained hepatitis B e antigen positive, most with unchanged biochemical features. Sixteen (62%) children among these 26 children were treated with interferon-alpha. Eleven (69%) children had seroconversion to anti-hepatitis B e within the first year after the cessation of therapy. Hepatocellular carcinoma developed in 1 of these 11 children at the age of 16 years, 6 years after interferon therapy. Thus, hepatocellular carcinoma developed in two children in an anti-hepatitis B e positive phase.

CONCLUSION

All children carrying hepatitis B surface antigen should be observed carefully to monitor the possible development of hepatocellular carcinoma, especially in the antihepatitis B e-positive phase after spontaneous seroconversion or even after interferon treatment.

Salt-induced exacerbation of morning surge in blood pressure in patients with essential hypertension

The morning surge in blood pressure (BP) is related to the morning occurrence of lethal cardiovascular events. We tested the hypothesis that salt intake may be associated with the morning surge in BP in essential hypertension. Seventy-six patients were admitted and placed on a low salt diet (2 g/day) for 7 days followed by a high salt diet (20-23 g/day) for another 7 days. At the end of each salt diet, 24-h ambulatory BP and heart rate monitorings and head-up tilt (HUT) test were performed. Patients whose average mean BP (MBP) was increased by more than 10% by salt loading were assigned to the salt-sensitive (SS) group (n = 37); the remaining patients, whose MBP was increased by less than 10%, were assigned to the non-salt-sensitive (NSS) group (n = 39). The increase in ambulatory MBP during 6.30-8.00 am above the baseline (2.00-4.00 am) was significantly enhanced by salt loading in the NSS group (P < 0.05), but not in the SS group. The coefficient of variation of 24-h MBP and heart rate was increased by salt loading only in the NSS group. The significant elevation of plasma noradrenaline concentration after awakening, which was noted during the low salt diet period, was unchanged during the high salt diet period in the NSS group, but abolished in the SS group. Salt loading enhanced HUT-induced decrease in systolic BP without affecting the heart rate response only in the NSS group. We conclude that the morning surge in BP is enhanced by salt loading in the NSS type of essential hyper- tension, presumably by the excessive activation of the sympathetic nervous system. Journal of Human Hypertension (2000) 14, 57-64.

Participation of angiotensin II and bradykinin in contractile function in dog stunned myocardium

We examined the effects of enalapril and 4'-[(1, 4'-dimethyl-2'-propyl-[2,6'-bi-1H-enzimidazole]-1'-yl)methyl]-[1, 1'-biphenyl]-2-carboxylic acid (BIBR-277), an angiotensin II receptor antagonist, on contractile dysfunction in the stunned myocardium. Dogs were subjected to 20-min ligation of the coronary artery, followed by 60-min reperfusion. Saline, enalapril (1 mg/kg or 3 mg/kg), or BIBR-277 (3 mg/kg) was injected i.v. 10 min before ligation. D-Arginyl-L-arginlyl-L-prolyl-trans-4-hydroxy-L-prolylglycyl -3-(2-thi enyl)-L-alanyl-L-seryl-D-1,2,3, 4-tetrahydro-3-isoquinolinecarbonyl-L-(2alpha, 3beta, 7abeta)-octahydro-1H-indole-2-carbonyl-L-arginine (Hoe-140), a bradykinin B(2) receptor antagonist, at 300 microg/kg was injected i. v. 10 min before drug injection. Contractile function was assessed on the basis of percentage segment shortening (%SS). ATP levels were measured in 60-min reperfused hearts. %SS significantly decreased during ischemia, and recovered during reperfusion, although the %SS was significantly less than the pre-ischemic level. Both enalapril at either dose and BIBR-277 significantly enhanced %SS recovery during reperfusion, an effect which was associated with a tendency toward energy preservation. Hoe-140 completely abolished the effect of enalapril at either dose, while it did not modify that of BIBR-277. Inhibition of angiotensin II formation and bradykinin breakdown may be separately related to the improvement of myocardial stunning.

Urokinase-type plasminogen activator and plasminogen activator inhibitor antigen in tissue extracts of paranasal sinus mucous membranes affected by chronic sinusitis and antrochoanal polyps

We examined the effect of pH on the extraction of urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor-1 (PAI-1) from paranasal sinus mucous membrane associated with chronic sinusitis and antrochoanal polyps. The specific activity of u-PA extracted with buffer at pH 7.4 was stronger than that extracted with buffer at pH 4.2. The antigen level of u-PA extracted with the acidic buffer was significantly higher than that extracted with the neutral buffer. In contrast, the difference in antigen levels of PAI-1 extracted with the acidic buffer and neutral buffer was not significant. Based on these results, we inferred that the u-PA-PAI-1 complex was extracted by the acidic buffer and the activity of u-PA was therefore decreased.

Determination of concentrations of flecainide in human serum by high-performance liquid chromatography on a fluorocarbon-bonded silica gel column

An optimized method for the determination of flecainide in serum is presented. Extraction using a solid-phase C18 column and chromatography on a stabilized fluorocarbon-bonded silica gel column effectively separate flecainide from an internal standard (a positional isomer of flecainide). The HPLC apparatus and conditions were as follows: analytical column, Fluofix 120N; sample solvent, 20 microl; column temperature, 40 degrees C; detector, Shimadzu RF-5000 fluorescence spectrophotometer (excitation wavelength = 300 nm, emission wavelength = 370 nm); mobile phase, 0.06% phosphoric acid containing 0.1% tetra-n-butyl ammonium bromide-acetonitrile (75:25, v/v); flow-rate, 1.0 ml/min. The standard curves for flecainide were linear in the concentration range examined (10-2000 ng/ml). The regression equation was y = 0.08+0.0078x (r = 0.9998). The minimum detectable amount of flecainide was approximately 5 ng/ml. In the within-day study, the precision coefficients of variation were 2.66, 2.18, 2.54, 2.72, 2.88, 2.24, and 3.29% for the 10, 50, 100, 200, 500, 1000, and 1500 ng/ml standards, respectively. The absolute recovery rates of flecainide at each concentrations were 94-100%. The method described provides analytical sensitivity, specificity and reproducibility suitable for both biomedical research and therapeutic drug monitoring.

Multielement compositions of marine phytoplankton samples from coastal areas of Japan by instrumental neutron activation analysis

Phytoplankton samples were collected during spring bloom of diatoms from three coastal areas of Japan using a NORPAC P-25 net (25-micron opening) with a NGG52 prenet (335-micron opening), and 25 major and trace elements have been analyzed by INAA. Concentration ranges of analyzed phytoplankton samples are much wider than the concentration ranges compiled by Bowen (1979) except for As, and data of marine phytoplankton samples for Br, Sb, Hf, Sc, La, Ce, Sm, and Eu were not included in the compilation. The 25 analyzed elements have been categorized into three groups: elements showing positive correlation with Br, positive correlation with Al, and no positive correlation with Br or Al. The marine phytoplankton samples have been plotted on a Masuzawa-Koyama-Terazaki (MKT) plot and it proved that the MKT plot is applicable to marine phytoplankton samples.