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A 53-year-old woman with severe coronavirus disease 2019 (COVID-19) pneumonia was admitted and treated with intravenous unfractionated heparin for thromboprophylaxis under general anesthesia with mechanical ventilation. She developed right hemiparesis after hospitalization due to a large hemorrhagic infarction. Her platelet count decreased from 243,000/μL at administration to 121,000/μL. Anti-platelet factor 4-heparin antibody testing was positive according to a latex immunoturbidimetric assay. She was therefore diagnosed with heparin-induced thrombocytopenia. We immediately stopped the heparin and started argatroban; the platelet count recovered, and thrombosis did not relapse. Physicians should consider heparin-induced thrombocytopenia as a cause of ischemic stroke in patients with COVID-19 infection.

Objective Various neurological manifestations have been increasingly reported in coronavirus disease 2019 (COVID-19). We determined the neurological features and long-term sequelae in hospitalized COVID-19 patients. Methods We retrospectively studied 95 consecutive hospitalized patients with COVID-19 between March 1 and May 13, 2020. Acute neurological presentations (within two weeks of the symptom onset of COVID-19) were compared between 60 non-severe and 35 severely infected patients who required high-flow oxygen. In the 12 ventilated patients (the most severe group), we evaluated neurological complications during admission, subacute neurological presentations, and neurological sequelae (51 and 137 days from the onset [median], respectively). Results Of the 95 patients (mean age 53 years old; 40% women), 63% had acute neurological presentations, with an increased prevalence in cases of severe infections (83% vs. 52%, p

Recently, 5G wireless communications system has been deployed in 28 GHz band. Due to high propagation loss of EM waves, there are few paths which can reach receiving antenna when a blockage exists. In order to increase number of propagation paths and increase EM coverage for the system, checkerboard structures for diffusing EM waves emitted from transmitting antenna has been designed. The EM diffusion performance for different number of scattering elements was numerically evaluated and it was found that EM diffusion performance can be significantly improved by inverting the reflection phase of one element in the checkerboard pattern.

We retrospectively examined the differences between paramedic triage and final diagnosis in the cases that were transported to our hospital between May 2016 and March 2019. About 30% of the patients with suspected stroke were diagnosed other than stroke. Some of the patients without suspected stroke were diagnosed with large vessel occlusion and were treated with mechanical thrombectomy. The time from arrival at the hospital to treatment was significantly longer in the patients without suspected stroke than with suspected stroke. To achieve a better prehospital care, we need to accept a wide range of stroke mimics, and to continuously feedback the paramedics about the importance of paralysis, cortical symptoms in stroke.

5G mobile communication systems use electromagnetic (EM) waves in the 28 GHz. The EM waves are scattered in a specular direction with sharp beam width by walls and radio waves in this frequency band is large propagation loss. If there are object for shielding EM waves between the receiver and transmitter inside the room, the quality of the wireless communication systems is deteriorated because of the received antenna can receive neither direct waves, reflected nor scattered waves. In this research, an EM scattering wall will be designed on the basic of array antenna theory to reduce unreachable area and to improve the quality of wireless communications in the room. Finally, the performance of the designed EM scattering wall is evaluated in terms of diffusion coefficients.

Background We experienced two cases of ischemic stroke resulting from carotid artery occlusion associated with acute type A aortic dissection (ATAAD), in which carotid artery stenting before the surgery for ATAAD resulted in good clinical outcomes. Case 1 description: A 63-year-old woman was hospitalized for conscious disturbance, right hemiparesis, and total aphasia. Computed tomography of the head showed no abnormal findings. Computed tomography angiography showed ATAAD and bilateral common carotid artery occlusion. Surgery was not indicated for ATAAD because of a poor prognosis of ischemic stroke. However, carotid artery stenting of the left common carotid artery occlusion was successfully performed, and her neurological findings improved. The patient underwent hemiarch replacement for ATAAD on the day after carotid artery stenting. Her final modified Rankin Scale was 1. Case 2 Description: A 57-year-old woman was hospitalized for mild left hemiparesis. Magnetic resonance imaging showed right watershed infarction and right common carotid artery occlusion. Computed tomography angiography showed ATAAD. After hospitalization, conscious disturbance appeared and left hemiparesis worsened. Ischemic stroke indicated a poor prognosis for revascularization by surgery for ATAAD. Thus, carotid artery stenting of the right common carotid artery occlusion was performed. The patient’s neurological findings improved and she underwent hemiarch replacement for ATAAD at 19 days after carotid artery stenting. Her final modified Rankin Scale was 1. Conclusions In the present cases, although ischemic stroke was serious and precluded surgical indication for ATAAD, carotid artery stenting before surgery for ATAAD resulted in good clinical outcomes. Performing carotid artery stenting before surgery for ATAAD is challenging but achievable, and is a valid treatment option depending on the individual cases.

Background and Purpose: Efficacy of mechanical thrombectomy for acute cerebral large vessel occlusion depends on time from symptom onset to reperfusion. While time to treatment in hospital has been optimized in these days, it is not well-known about improving time in pre-hospital when suspected stroke. We sought to analyze time from emergency medical services (EMS) dispatch to arterial puncture in stroke patients eligible for mechanical thrombectomy. Methods: We analyzed time components from EMS dispatch to puncture in patients with acute large vessel occlusion within 6 hours from onset treated with mechanical thrombectomy between April 2015 and December 2018. We assessed the associated factors with each time component and patient outcomes. Results: Consecutive 195 patients were included in this analysis. The median EMS dispatch-to-scene, on-scene, transport, door-to-puncture (DTP), and scene-to-puncture (STP) times were 4, 16, 12, 40, and 70 minutes, respectively. Percentage of favorable outcomes were significantly higher in patients with STP within 60 minutes (57.5% vs 35.8%, p Conclusions: Reducing time in pre-hospital and in-hospital interact with each other. Education program and use of direct call from EMS contributed to reducing these times.

Background Meningovascular neurosyphilis, a form of early neurosyphilis, can cause infectious arteritis, which can be complicated by cerebral infarction. High-resolution vessel wall imaging (HR-VWI) is one of the techniques used to directly visualize the vessel wall. Herein, we present a rare case of meningovascular neurosyphilis, in which intracranial arterial vasculitis was evaluated using HR-VWI. Case presentation A 22-year-old man with no medical history of any condition was brought to the emergency room with one day history of right upper and lower extremity weakness. Diffusion-weighted magnetic resonance (MR) imaging showed a high signal from the left putamen to the corona radiata, and MR angiography showed stenosis of the right internal carotid artery (ICA) and the bilateral middle cerebral arteries (MCAs). HR-VWI showed thickening, along with smooth, intense, and concentric enhancement of the right ICA and the bilateral MCAs. The patient was diagnosed with neurosyphilis based on the findings of the blood tests and cerebrospinal fluid examination. The patient's symptoms gradually improved after treatment with intravenous penicillin G and oral antiplatelet agents. HR-VWI, performed approximately 6 months after the treatment, revealed improvement in the contrast enhancement of the vessel wall and the vascular stenosis. Conclusion To the best of our knowledge, this is the first report of meningovascular neurosyphilis that evaluated the course of treatment using HR-VWI. Our report highlights the effectiveness of HR-VWI to determine the effects of treatment on meningovascular neurosyphilis.

Precipitation processes play a critical role in the longevity and spatial distribution of stratocumulus clouds through their interaction with the vertical profiles of humidity and temperature within the atmospheric boundary layer. One of the difficulties in understanding these processes is the limited amount of observational data. In this study, robust relations among liquid water path (LWP), cloud droplet number concentration (Nd) and cloud base rain rate (Rcb) from three subtropical stratocumulus decks are obtained from A-Train satellite observations in order to obtain a broad perspective on warm rain processes. Rcb has a positive correlation with LWP/Nd and the increase of Rcb becomes larger as LWP/Nd increases. However, the increase of Rcb with respect to LWP/Nd becomes more gradual in regions with larger Nd, which indicates the relation is moderated by Nd. These results are consistent with our theoretical understanding of warm rain processes and suggest that satellite observations are capable of elucidating the average manner of how precipitation processes are modulated by LWP and Nd. The sensitivity of the auto-conversion rate to Nd is investigated by examining pixels with small LWP in which the accretion process is assumed to have little influence on Rcb. The upper limit of the dependency of auto-conversion rate on Nd is assessed from the relation between Rcb and Nd, since the sensitivity is exaggerated by the accretion process, and was found to be a cloud droplet number concentration to the power of −1.44 ± 0.12.

An 80-year-old woman had an aortic valve replacement 1 month before admission and took warfarin for transient atrial fibrillation. She developed a disturbance of consciousness and left hemiplegia. On admission, the right radial artery was slightly palpable. Head MRI images showed a hyper-intense area in the right middle cerebral artery territory. MRA images showed an occlusion of the right M1 distal site and decreased signal at the right internal carotid artery. Contrast CT images of the ascending aorta showed an embolus in the innominate artery. She was diagnosed with an innominate artery saddle embolus and occlusion of the right cerebral artery due to cardiac embolism. She was treated with a heparin infusion and warfarin. She recovered consciousness and from hemiplegia gradually. Recanalization of the innominate artery and right cerebral artery was confirmed. In cases where the radial artery is slightly palpable, it is necessary to consider an innominate artery saddle embolus in addition to aortic dissection.

In recent year, 5th-generation mobile communication system is developed. In the system, 24-28 [GHz] frequency will be used. Mobile devices such as smartphone are used in the vicinity of a head in a talking mode; therefore, some EM wave exposure to a human head will be localized. In order to evaluate the positive effect of human health, animal experimental studies are necessary. In order to realize local exposure during smartphone using for the animal experiments, local exposure antennas [1] [2] are required. In this research, local exposure antenna is proposed. The working frequency of this research is 26.5 [GHz].

We report the case of a 27-year-old woman with acute internal carotid artery occlusion long after carotid artery revascularization by vein graft. She presented with sudden unconsciousness and left hemiparesis. Her right carotid artery was revascularized with an ipsilateral internal jugular vein graft during a carotid body tumor resection 10 years ago. Computed tomography angiography revealed a right internal carotid artery terminus occlusion. Intravenous rt-PA and mechanical thrombectomy were performed, resulting in successful recanalization. Her neurological symptoms gradually recovered. When examining the embolic source, carotid ultrasonography for the vein graft showed intimal thickening, some high-echoic plaques, and lumen dilation, but no thrombus was observed. Color Doppler imaging showed laminar flow at the graft. Angiography after thrombectomy also showed pooling of contrast at the vein graft. We suspected that the blood flow stagnation at the vein graft induced thrombus formation; therefore, anticoagulation therapy was initiated. One year later, she was independent without recurrence of stroke, and anticoagulation therapy was replaced with aspirin because she went abroad. However, a carotid ultrasonography exam the following year revealed a huge thrombus at the graft. Anticoagulation therapy was resumed; subsequently, the thrombus decreased. In conclusion, we could monitor the long-term change in the vein graft by ultrasonography. Moreover, anticoagulation therapy was more effective.

In this days, the next generation wireless communication system such as 5th generation mobile communication is developed. In the system, higher frequency band such as 28 GHz will be used. On the other hand, mobile devices such as smartphone are used in the vicinity of a head in a talking mode, therefore, some EM wave exposure to a human head will be local exposure. In order to evaluate the positive effecton human health, an animal experimental study is necessary. In order to realize local exposure during mobile phone using for the animal experiment, an EM wave local exposure antenna is required. In the animal experiments, electromagnetic wave energy absorption should be focused on a head region of laboratory small animals. In this paper, our developed local exposure system including an antenna for the animal experiment is reported. The working frequency of this system is 26.5 GHz.

We propose a patch antenna for animal experiments. The proposed devise is operated with the fifth generation of mobile communication at 26.5 GHz. In this study, we consider the target exposure area to be a superficial of a rat brain. Then, we verify the effectives of the proposed antenna for local exposure by simulation analysis.

Background and Purpose: Endovascular therapy (EVT) for acute ischemic stroke (AIS) is now proven by pivotal randomized controlled trials (RCTs) to produce clinically large benefits. In early 2015, following publication of these RCTs, we implemented a new institutional acute stroke care protocol to improve outcomes of patients with AIS, especially by reducing onset-to-reperfusion (OTR) time. We sought to analyze the temporal trends in EVT for AIS at our hospital and evaluate the effect of this intervention. Methods: We analyzed the temporal trends in EVT for AIS and compared patients who underwent EVT for AIS in the pre intervention (April 2010 - March 2015) and post intervention (April 2015 - March 2017) period. Using univariate methods and multivariable logistic regression, we assessed the associated factors with favorable outcomes. Results: Among 2657 patients with AIS, 322 (12.1%) underwent EVT. The mean age was 74.4 and the median baseline NIHSS was 19. The percentage of patients with EVT significantly increased from 9.7% pre intervention to 18.0% post intervention. Patients over 90 years old, with M2 occlusion, and received IV-tPA were significantly increased in post intervention period (P Conclusions: EVT for AIS accelerated markedly in the two years following RCTs publication and our new institutional acute stroke care protocol reduced DTP and OTR times. Reducing OTR times was associated with improving patient outcomes.

This paper describes the printed dipole antenna impedance that is calculated using the ideal reflection phase of the AMC. Moreover, the optimum reflection phase of the AMC reflector for best relative bandwidth is described. From the result, the wide RBW was realized by the low distance of the printed dipole antenna and RBW PMC = 20∼30%. Moreover, the printed dipole antenna distance that had the widest RBW was shown.

The present study has carried out numerical analysis for turbulent flow developing in a sinuous duct with a square sectioned at Reynolds number of 4×104. The sinuous duct was formed from three 180 degree bends with 80 mm hydraulic diameter and 160 mm mean radius of curvature. Straight ducts of 80 and 30 hydraulic diameter long are attached to the inlet and outlet planes of the sinuous duct, respectively. In calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulence precisely, and boundary-fitted coordinate system was introduced as the method of coordinate transformation. Calculated results were compared with the experimental data measured by hot-wire velocimeter. As a result of the comparison, it was found that the present method was able to reproduce the main features of streamwise mean-velocity and secondary flow although the agreement was certainly not perfect in all detail. As a great discrepancy, it is pointed out that the calculated intensity of the secondary flow near 90 degree of second and third bend shows greater value than the experimental data. Moreover, the pressure-driven, Reynolds stress-driven and centrifugal forces which generates the secondary flow, are evaluated quantitatively by using momentum transport equation. It is clarifyed that Reynolds stress-driven force also plays an important role near 90 degree of second and third sinuous duct.

Numerical simulation has been performed for developing turbulent flow in S-shaped duct with a square section at a Reynolds number of 4×104. The S-duct was formed from two 22.5 degree bends with 40 mm hydraulic diameter and 280 mm mean radius of curvature. Straight ducts with hydraulic diameters of 7.5 and 50 are attached to the inlet and outlet planes of the S-duct, respectively. In calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulent flow precisely, and a boundary-fitted coordinate system was introduced for coordinate transformation. The calculated results were compared with the experimental data using a laser Doppler velocimeter. In particular, the distributions of Reynolds stresses are compared in this report. As a result of comparison with the experimental data, it was found that the present method can accurately predict contours of streamwise normal stress which show the active generation of turbulence near the outer wall of the second bend. Moreover, it was clarified by estimating the production term that the high value of streamwise normal stress near the outer wall of the second bend is responsible for the velocity gradient of streamwise mean velocity with respect to the radial direction. The profiles of other normal stresses and shear stress are also predicted using the anisotropic turbulent model without great discrepancy.

A numerical study has been performed on turbulent flow developing in a 90 deg curved duct of retangular cross section and an aspect ratio of 6. The ratio of bend mean radius of curvature to hydraulic diameter is 2.04 and straight ducts of 7.5 and 25.5 width are attached to the inlet and outlet of the bend, respectively. In addition to this straight duct. two-dimensional lateral contraction of the wind tunnel with an area ratio of 6 is considered as the numerical domain as well as the experimental apparatus. Calculated results were compared with the experimental data measured for Reynolds stress components in detail. In this calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulence precisely, and a boundary-fitted coordinate system was introduced as the method of coordinate transformation. As a result of this examination, the present method can predict normal and shear stresses distributions of the inlet straight duct but cannot reproduce the characteristic destabilizing effect and shows an increase in the turbulence intensity close to the outer wall in the curved duct. The discrepancy may be caused by use of the wall function as the boundary condition. In the outlet straight duct. the calculated value of normal and shear stresses are smaller than those of the experiments.

A numerical analysis of developing turbulent flow in a diffuser with S-shaped centerline at a Reynolds number of 4×104 has been carried out. The diffuser exit-to-inlet area ratio was 1.5, the inlet cross section was square, 40mm×40mm, and was expanded on both curved surfaces to an exitplane section of 40mm×60mm. The S-shaped curvature was formed from two 22.5 degree bends of 280mm mean radius of curvature. Straight ducts 0.3m and 2m long were attached to the inlet and outlet planes of the S-shaped diffuser, respectively. In the calculation, an algebraic Reynolds stress model was adopted for predicting anisotropic turbulence precisely, and a boundary-fitted coordinate system was introduced for coordinate transformation. Calculation results for mean velocity were compared with the experimental data. In addition, the difference in flow between the S-shaped diffuser and the S-shaped duct is presented with calculation results. Using by the present method, we found that the flow at the inlet shows a "core" flow located near the inner wall of the first bend, and a region of low velocity fluid which has accumulated at the exit of the diffuser was observed. It was also found that the secondary flow patter of the S-shaped diffuser was similar to that of the S-shaped duct in the first bend but differed from it in the second bend.

A numerical analysis has been carried out for developing turbulent flow in a diffuser with S-shaped centerline at a Reynolds number of 4×104. The diffuser exit-to-inlet area ratio was 1.5 and the inler cross section was square, 40mm×40mm, and expanded on both curved surfaces to an enitplane section of 40mm×60mm. The S-shaped curvature was formed from two 22.5 degree bends of 280mm mean radius of curvature. Straight ducts 0.3m and 2m long are attached to the inlet and outlet planes of the S-shaped diffuser, respectively. In the calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulence precisely, and a boundary-fitted coordinate system was introduced as the method of coordinate transformation. Special attention is paid to the comparison of Reynolds stresses between calculation results and experimental data. In addition, the difference in turbulent structure between S-shaped diffuser and S-shaped duct is presented by invariant analysis using the calculation results. The present method can be used accurate prediction of the characteristic features of normal and shear stresses. Invariant maps of the S-shaped diffuser show that the turbulent structure transforms anisotropic turbulent flow into a two-dimensional turbulent flow. Moreover, the calculation results suggent that the turbulence level of the S-shaped diffuser increases more actively than does that of the S-shaped duct.

A numerical analysis has been carried out of developing turbulent flow in S-shaped duct with a square cross section at a Reynolds number of 4×104. The S-duct was formed from two 22.5 degree bends with 40 mm hydraulic diameter and 280 mm mean radius of curvature. Straight ducts with hydraulic diameters of 7.5 and 50 are attached to the inlet and outlet planes of the S-duct, respectively. In calculation, an algebraic Reynolds stress model was adopted in order to predict anisotropic turbulence precisely, and boundary-fitted coordinate system was introduced as the method of coordinate transformation. Calculated results were compared with the experimental data obtained using a laser Doppler velocimeter. As a result of the calculation, it was predicted without conflict with the experimental data that the flow at the inlet shows a "core" flow located nearer the inner wall of the first bend and a region of low-velocity fluid accumulated at the exit of the S-duct is observed. Moreover, the transition from the secondary flow of the first kind to that of the second kind is examined in the outlet straight duct. It was found that after reaching a maximum value near the S-duct outlet, the secondary flow decays and gradually transforms to the secondary flow of the second kind at a hydraulic diameter of about 18 from the bend outlet.

A high gain and low-profile antenna can be realized by using an AMC (Artificial Magnetic Conductor) reflector that has PMC (Perfect Magnetic Conductor) characteristics. Since a configuration of the AMC reflector must be adjusted for each antenna, studies on the configuration of the optimum AMC reflector are not enough yet. This paper describes the optimum AMC reflector configuration for high directive gain and low-profile dipole antenna with the AMC reflector. Here, the arranged unit cell area and the thickness of the AMC reflector are considered. The AMC treated in this paper are composed of the patch or loop type FSS (Frequency Selective Surface) and the ground plane. It is shown that the area of the arranged unit cell is one of the important factors to obtain the high directive gain. Moreover, it is shown that the high directive gain dipole antenna with the AMC reflector can be realized by the optimum area of the arranged unit cell.

A numerical analysis has been performed on developing turbulent flow in a square-sectioned 180 deg bend. The ratio of bend mean radius of curvature to hydraulic diameter is 3.375 and a straight duct 6 hydraulic diameters long is attached to the inlet plane of the bend. In calculation, an algebraic stress model was adopted in order to predict Reynolds stresses precisely, and a boundary-fitted coordinate system was introduced as the method of coordinate transformation. Calculated results were compared with the experimental data available. Moreover, the influence of boundary layer thickness at the bend entry is examined using the calculated results. As a result of this study, we conclude that the present method can predict well the mean flow velocity as well as its a minimum and the measured spike velocity in streamwise velocity fluctuations near the symmetry at 90 deg. Furthermore the calculated results confirm that thinner entry boundary layers in the turbulent flow give rise to lower cross-stream velocity. As a characteristic feature, it is pointed out that the secondary flow breaks down into several eddies in the place of the classical single vortex structure when the boundary layers are thin. Therefore, distorted contour lines of streamwise flow appear at angles greater than 90 deg where the secondary flow begins to break down.

食品の劣化や褐変に関与する金属含有の酸化還元酵素を中心に,酵素に対する超臨界二酸化炭素(SC-CO2)の影響を調べた.各種酵素の水溶液にSC-CO2を圧力10-20MPa,温度35℃で0-120分および20時間導入したところ,カタラーゼ,ペルオキシダーゼ,ポリフェノールオキシダーゼは,SC-CO2処理により容易に活性が低下した.その効果は時間が長くなるほど,また圧力が高いほど顕著であった.一方,リパーゼやピルビン酸デカルボキシラーゼはSC-CO2処理による著しい活性の低下は見られなかった.以上より,酵素の種類によりSC-CO2に対する感受性が異なることが明らかとなった.このことは,SC-CO2処理の条件(温度や圧力)を適当に選択することにより,食品中の特定の酵素だけを失活させることが可能なことを示唆した.

The unfolding of alpha-momorcharin was systematically investigated using steady-state and time-resolved tryptophan fluorescence, circular dichroism and 8-anilino-1-naphthalenesulfonic acid (ANS) binding. These spectroscopic studies demonstrated that alpha-momorcharin unfolded through a compact folded intermediate state. The content of alpha-helix was increased, Trp192 approached closer to the side of active site and its rotational motion was restricted by being equilibrated with 2-3 M of guanidine hydrochloride. Furthermore, the binding of ANS with alpha-momorcharin was more suppressed to show that the hydrophobic parts would not be accessed to the protein surface but rather be sealed off in this specific conformation state. These results suggest that the structure of alpha-momorcharin holds the more compact conformation as an incipient state for unfolding, which is the sharp contrast to beta-momorcharin that gives the characteristics of the generally known molten globule state.

Nine species of benthic dinoflagellates collected in subtropical waters were cultured, extracted, and tested for mouse lethality, ichthyotoxicity, and hemolytic activity. Hemolytic activity was detectable in all species, but the activities of Amphidinium carteri, A. klebsi, and Gambierdiscus toxicus were outstanding. G. toxicus showed the most potent mouse lethality. Two hemolytic constituents of A. carteri were determined to be mono- and di-galactoglycerolipids. Maitotoxin, produced by G. toxicus, was suggested to have a molecular weight of 3402 ± 2 (m/z). Two potent toxins against mice were isolated from Prorocentrum lima and identified as okadaic acid and 5-methylene-6-hydroxy-2-hexen-1-okadaate.

Five species of dinoflagellates and three microalgae of benthic habitat collected in French Polynesia were grown in unialgal state and tested for toxicity on mice and for hemolytic activity. Two diethyl ether soluble toxins (PL toxin-I, II) and one fast-acting toxin soluble in 1-butanlo (PL toxin-III) were found in Prorocentrum lima. The chromatographic behaviors of PL toxin-I and II closely resembled those of scaritoxin and ciguatoxin prepared from ciguateric fishes. Potent hemolytic substance was present in Amphidinium sp. This species was also toxic to mice. No remarkable activity was detected in the following species: Coolia monotis, Amphidinium sp.-2, and Gymnodinium sp. (dinoflagellates); Chloococcopsis sp. and Isochrysis sp. (blue-green algae); and Nitzschia panduriformis (diatom).

Two diethyl ether soluble toxins (PL toxin-I, II) and one 1-butanol soluble toxin (PL toxin-III) were isolated from a benthic marine dinoflagellate Prorocentrum lima. The major toxic component, PL toxin-II, was purified by several steps of column chromatography to yield colorless crystals: mp. 156-158°C, [α]20D+23° Physical and chemical data pointed to a molecular formula C44H68O13 having four hydroxyls, one carboxyl, seven ether linkages, three olefins, and five methyls in the molecule. A further examination of its properties and a comparison with an authentic specimen established that PL toxin-II is identical with okadaic acid, recently isolated as a cytotoxic component of two sponges Halichondria okadai and H. melanodocia.