The efficacy and safety of alteplase treatment in patients with acute ischemic stroke with unknown time of onset: -Real world data

INTRODUCTION

Treatment with alteplase for acute ischemic stroke patients with an unknown time of onset is safe and effective. However, clinical trials have some selection bias. The purpose of this study was to clarify the efficacy and safety of alteplase treatment in patients with unknown time of onset in a real-world clinical setting.

METHODS

We included consecutive patients with acute ischemic stroke visited within 4.5 h of onset or symptom recognition. We divided patients into two groups: onset clear group (C-group) and unknown time of onset group (U-group). We treated patients with an unknown time of onset if the DWI-FLAIR mismatch was positive. We calculated the prevalence of alteplase treatment in each group and compared prognosis between the two groups.

RESULTS

Six hundred thirty-two patients arrived within 4.5 h of onset or symptom recognition. Of these, 446 patients (71 %) were in the C-group and 186 (29 %) in the U group. Alteplase treatment was performed in 35 % of patients in the C group and in 18 % in the U group (p < 0.001). Favorable outcomes at 90 days in patients treated with alteplase were comparable between the C group (52 %) and the U group (53 %) (p = 0.887). All hemorrhagic complications, including non-symptomatic hemorrhagic transformation, occurred in 11 of 157 patients (7 %) in the C-group and one of 34 patients (3 %) in the U-group (p = 0.696).

CONCLUSION

In a real-world clinical setting, alteplase treatment was performed safe in 18% of patients with an unknown time of stroke onset based on patient selection using the DWI-FLAIR mismatch.

Various effects of nutritional status on clinical outcomes after intracerebral hemorrhage

Although the assessment of nutrition is essential for stroke patients, detailed associations between nutritional status at admission, subsequent complications, and clinical outcomes in patients with acute intracerebral hemorrhage (ICH) are unclear. We aimed to elucidate these associations using the Controlling Nutritional Status (CONUT) score. Consecutive patients with acute ICH were investigated. Nutritional status was evaluated using the CONUT score, calculated from the serum albumin level, lymphocyte count, and total cholesterol level. Subsequent complications, such as hemorrhage expansion (HE) during the acute stage and aspiration pneumonia during hospitalization, were evaluated. Poor outcome was defined as a modified Rankin Scale score of ≥ 3 at 3 months. Of the 721 patients, 49 had HE, 111 had aspiration pneumonia, and 409 had poor outcomes. Patients with HE had significantly lower total cholesterol levels than those without HE. Patients with aspiration pneumonia had significantly lower albumin levels, lower lymphocyte counts, and higher CONUT scores than those without aspiration pneumonia. Patients with poor outcomes had significantly lower albumin levels, lower lymphocyte counts, lower total cholesterol levels, and higher CONUT scores than those with good outcomes. Multivariable logistic analysis showed that higher CONUT scores were independently associated with poor outcome (odds ratio, 1.28; 95% confidence interval, 1.09-1.49; P = 0.002) after adjusting for baseline characteristics, HE, and aspiration pneumonia. Each component of CONUT was a useful predictor of subsequent complications. Malnutrition, determined using the CONUT score, was independently associated with poor outcomes in patients with ICH after adjusting for these complications.

cnm-Positive Streptococcus mutans and diffusion-weighted imaging hyperintensities in acute intracerebral hemorrhage

BACKGROUND

Strains of Streptococcus mutans expressing the cell surface collagen-binding protein, Cnm, encoded by cnm (cnm-positive S. mutans), are associated with hypertensive intracerebral hemorrhage (ICH) and the occurrence of cerebral microbleeds (CMBs). Small diffusion-weighted imaging (DWI) hyperintensities in patients with acute ICH are also associated with CMBs. However, the association between cnm-positive S. mutans and DWI hyperintensities is unclear. Hence, this study aimed to investigate the association between cnm-positive S. mutans and DWI hyperintensities in patients with acute ICH.

METHODS

Patients with acute ICH were prospectively registered at three hospitals. Dental plaque specimens were collected within 4 days after admission, and cnm-positive S. mutans was detected using the polymerase chain reaction. Magnetic resonance imaging at 14 ± 5 days after admission was used to evaluate DWI hyperintensities and CMBs.

RESULTS

A total of 197 patients were enrolled in this study. cnm-positive S. mutans was detected in 30 patients (15.2%), and DWI hyperintensities were observed in 56 patients (28.4%). Patients with cnm-positive S. mutans had a higher frequency of DWI hyperintensities (50.0% vs 24.6%; p = 0.008) and a higher number of CMBs (5.5 vs 1.5; p < 0.001) than those without cnm-positive S. mutans. Multivariable logistic analysis revealed that the presence of cnm-positive S. mutans was independently associated with DWI hyperintensities (OR 2.38; 95% CI 1.01-5.61; p = 0.047) after adjusting for several confounding factors.

CONCLUSION

This study found an association between the presence of cnm-positive S. mutans and DWI hyperintensities in patients with acute ICH.

Abstract TP159: Unilateral Spatial Neglect as an Independent Prognostic Factor for Poor Fim Efficiency in Patients With Mild to Moderate Ischemic Stroke

Background and Purpose: Unilateral spatial neglect (USN) is often observed in ischemic stroke patients suffered their right parietal lobe. USN is an obstacle to undergo rehabilitation smoothly, then might influence the recovery of activities of daily living (ADL) after stroke. We aimed to clarify the association between the presence of USN after ischemic stroke and the ADL improvement.

Methods: Consecutive patients with first-ever ischemic stroke and left limb paralysis who admitted to within 7 days from onset during February 2011 and March 2019 were included. Patients met the following criteria were excluded: mRS ≥3 before onset, NIHSS >15 on admission, without left limb paralysis, and missing NIHSS or functional independence measure (FIM) score on admission. Multiple regression analysis was performed to investigate the association between FIM efficiency score of acute phase and following factors: age, sex, acute reperfusion therapy (using an intravenous infusion of recombinant tissue plasminogen activator and/or endovascular therapy), FIM score on admission, and other clinical characteristics. All data were collected retrospectively using our electrical health record.

Results: 721 ischemic stroke patients with left limb paralysis (320 women, median age 76) were included. Median FIM efficiency score was significantly lower in patients with USN than without USN (n=240, 481; 0.83 vs 1.63, respectively). Multiple regression analysis showed that USN, age, and acute reperfusion therapy were significant prognostic factors of FIM efficiency (coefficient and 95% confidence interval [CI]: -0.135 [-0.771 to -0.153], -0.106 [-0.022 to -0.002], and 0.224 [0.136 to 0.305], respectively).

Conclusions: USN significantly influence the recovery of ADL after ischemic stroke. Clinicians should adequately evaluate USN after stroke and undergo USN-specific rehabilitation for them to optimize the effect of post-stroke rehabilitation. USN-specific rehabilitation might lead to better FIM efficiency.

Warm Front Passage on the Previous Day Increased Ischemic Stroke Events

BACKGROUND AND PURPOSE

The influence of a weather front passage is rarely evaluated on stroke events. We hypothesized that a weather front passage on the stroke onset day or during the previous days may play an important role in the incidence of stroke.

METHODS

A multicenter retrospective study was conducted to evaluate the frequency of stroke events and their interaction with weather front passages. Consecutive acute stroke patients (n = 3935, 73.5 ± 12.4 years, 1610 females) who were admitted to 7 stroke hospitals in 3 cities from January 2012 to December 2013 were enrolled in this study. Multivariate Poisson regression models involving time lag variables were used to compare the daily rates of stroke events with the day of a weather front passage and the previous 6 days, adjusting for considerable influences of ambient temperature and atmospheric pressure.

RESULTS

There were a total of 33 cold fronts and 13 warm fronts that passed over the 3 cities during the study period. The frequency of ischemic stroke significantly increased when a warm front passed on the previous day (risk ratio 1.34, 95% confidence interval 1.07-1.69, P= .016).

CONCLUSIONS

This study indicated that a weather front passage on the previous days may be associated with the occurrence of stroke.

Off-Site Indoor Localization Competitions Based on Measured Data in a Warehouse

The performance of indoor localization methods is highly dependent on the situations in which they are used. Various competitions on indoor localization have been held for fairly comparing the existing indoor localization methods in shared and controlled testing environments. However, it is difficult to evaluate the practical performance in industrial scenarios through the existing competitions. This paper introduces two indoor localization competitions, which are named the "PDR Challenge in Warehouse Picking 2017" and "xDR Challenge for Warehouse Operations 2018" for tracking workers and vehicles in a warehouse scenario. For the PDR Challenge in Warehouse Picking 2017, we conducted a unique competition based on the data measured during the actual picking operation in an actual warehouse. We term the dead-reckoning of a vehicle as vehicle dead-reckoning (VDR), and the term "xDR" is derived from pedestrian dead-reckoning (PDR) plus VDR. As a sequel competition of the PDR Challenge in Warehouse Picking 2017, the xDR Challenge for Warehouse Operations 2018 was conducted as the world's first competition that deals with tracking forklifts by VDR with smartphones. In the paper, first, we briefly summarize the existing competitions, and clarify the characteristics of our competitions by comparing them with other competitions. Our competitions have the unique capability of evaluating the practical performance in a warehouse by using the actual measured data as the test data and applying multi-faceted evaluation metrics. As a result, we successfully organize the competitions due to the many participants from many countries. As a conclusion of the paper, we summarize the findings of the competitions.

Proposal on Drone Control Device with Tactile Display

In order to support the tele-operation of drone, a new devise that can be controlled easily and intuitively, is proposed. The proposed devise also can display the feedback information from drone by tactile display, and it employs two visualization modes, first one is to display the difference between the drone’s direction and control direction by using the position of violators. Second one is to display the difference between the drone’s direction and control direction by using various frequencies. Through the experimental comparisons, the effectiveness of the proposed system is confirmed.

Abstract WP267: Controlling Nutritional Status Score Predicts 3-Month Functional Outcome in Patients With Acute Ischemic Stroke

Background: Malnutrition is an independent risk factor of poor outcome in acute ischemic stroke patients, but the indicator of malnutrition has not been well-established. The Controlling Nutritional Status (CONUT) score is reported to be a useful prognostic value of malnutrition in the cardiovascular diseases and malignant tumors. We investigated the relationship between the CONUT score and functional outcomes in acute ischemic stroke patients.

Method: Acute ischemic stroke patients (n=264, 70±12 years old) within 7 days of stroke onset were consecutively studied. The CONUT score was calculated from the serum albumin, total peripheral lymphocyte count and total cholesterol and the CONUT score ≥5 was defined as malnutrition. In the present study, we obtained the blood samples for the CONUT score within 2 days after admission. The primary outcome was evaluated from the 3-month functional status: poor outcome as a modified Rankin Scale (mRS) score ≥ 3 and good outcome as a mRS score <3.

Results: Of the total enrolled cohort, 230 patients (87.1%) were assessed for the functional outcomes. The patients with poor outcome (n=85) were older, lower body mass index (BMI), and more frequently had atrial fibrillation, chronic heart failure and anemia, and less frequently had dyslipidemia and current smoking. In addition, the CONUT score and National Institutes of Health Stroke Scale (NIHSS) score at admission were significantly higher in the patients with poor outcome. As the CONUT score was higher, the proportion of patients with poor functional outcome increased, and the poor functional outcome exceed 70% when the score was ≥ 5. Univariate logistic analyses showed that the CONUT score ≥5 was significantly associated with poor outcome at 3 months (odds ratio [OR] 6.05, 95% confidence interval [CI] 2.95-13.09, P<0.001). After multivariate analysis, the CONUT score ≥5, initial NIHSS score, and current smoking were independently associated with poor outcome (OR 4.15, 95% CI 1.52-11.67, P=0.005, OR 1.23, 95%CI 1.15-1.34, P<0.001, OR 0.14, 95%CI 0.03-0.53, P=0.002, respectively).

Conclusion: The CONUT score at admission is expected to be a useful prognostic marker of a 3-month functional outcome in acute ischemic stroke patients.

Alpha-2-macroglobulin as a Promising Biological Marker of Endothelial Function

Aims: Alpha-2-macroglobulin (α₂MG) is thought to be associated with inflammatory reactions and procoagulant properties that might cause ischemic stroke. Endothelial dysfunction plays an important role in atherosclerosis development and in the occurrence of cardiovascular events. In this study, we investigated whether serum α₂MG levels, endothelial function, and endothelial progenitor cell (EPC) number were associated in patients with chronic stroke or cardiovascular risk factors.

Methods: Patients with a history of stroke or any established cardiovascular risk factors were enrolled in this study (n = 102; 69 men, 70.1 ± 9.2 years). Endothelial function was assessed by flow-mediated dilation (FMD). EPC numbers (CD34+/CD133+) were measured using flow cytometry (n = 91). Serum α₂MG levels were measured by nephelometry.

Results: Patients in the highest tertile of serum α₂MG levels were older (P = 0.019) and more frequently exhibited dyslipidemia (P = 0.021). Univariate-regression analysis revealed that increased α₂MG levels were negatively associated with FMD values (r = −0.25; P = 0.010), whereas increased EPC numbers were positively associated (r = 0.21; P = 0.044). Multivariate-regression analysis adjusted for male gender, hypertension, and severe white-matter lesions showed that serum α₂MG levels were independently associated with FMD values (standardized partial regression coefficient [β] −0.185; P = 0.033), although not significantly associated with EPC numbers.

Conclusion: Serum α₂MG levels might reflect endothelial dysfunction evaluated by FMD in patients with chronic stroke or cardiovascular risk factors.

Binding of 11C-Pittsburgh compound-B correlated with white matter injury in hypertensive small vessel disease

OBJECTIVE

¹¹C-Pittsburgh compound-B (¹¹C-PIB) positron emission tomography (PET) is used to visualize and quantify amyloid deposition in the brain cortex in pathological conditions such as Alzheimer's disease (AD). Intense ¹¹C-PIB retention is also observed in the white matter (WM) of both healthy individuals and AD patients. However, the clinical implications of this retention in brain WM have not been clarified. We investigated the relationship between the extent of white matter lesions (WMLs) and the binding potential of ¹¹C-PIB (BP_ND) in the WM in patients with hypertensive small vessel disease. We further examined the relationship between the extent of WMLs and BP_ND in WML and in normal-appearing white matter (NAWM).

METHODS

Twenty-one hypertensive vasculopathy patients, without AD and major cerebral arterial stenosis and/or occlusion, were enrolled (9 women, 68 ± 7 years). Regions of WML and NAWM were extracted using magnetization-prepared rapid gradient-echo and fluid-attenuated inversion recovery of magnetic resonance images. Volumes of interest (VOIs) were set in the cortex-subcortex, basal ganglia, and centrum semiovale (CS). BP_ND in the cortex-subcortex, basal ganglia, CS, WML, and NAWM were estimated on ¹¹C-PIB PET using Logan graphical analysis with cerebellar regions as references. The relationships between WML volume and BP_ND in each region were examined by linear regression analysis.

RESULTS

BP_ND was higher in the CS and basal ganglia than in the cortex-subcortex regions. WML volume had a significant inverse correlation with BP_ND in the CS (Slope = -0.0042, R ²  = 0.44, P < 0.01). For intra WM comparison, BP_ND in NAWM was significantly higher than that in WML. In addition, although there were no correlations between WML volume and BP_ND in WML, WML volume was significantly correlated inversely with BP_ND in NAWM (Slope = -0.0017, R ²  = 0.26, P = 0.02).

CONCLUSIONS

¹¹C-PIB could be a marker of not only cortical amyloid-β deposition but also WM injury accompanying the development of WMLs in hypertensive small vessel disease.

Temporal Trends in Stroke Severity and Prior Antithrombotic Use Among Acute Ischemic Stroke Patients in Japan

BACKGROUND

Few existing stroke registries allow for evaluation of stroke severity, stroke subtype and antithrombotic usage prior to stroke onset over a given time period. The present study aimed to elucidate temporal trends in initial presenting stroke severity, stroke subtype and prior antithrombotic use over a 12-year period in a Japanese multicenter stroke registry.

METHODS AND RESULTS

We included 71,017 acute ischemic stroke patients (72±12 years old; 27,445 women) from the Japan Standard Stroke Registry Study (JSSRS) who were admitted to 94 hospitals between 2001 and 2012. The mean age of stroke onset increased gradually over time (P<0.001). Cardioembolic stroke patients (n=19,247) exhibited more severe NIHSS scores when compared with those with non-cardioembolic stroke (n=50,427). The proportion of cardioembolic stroke patients tended to increase over time, rising from 25.9% in 2001-2002 to 30.2% in 2011-2012 (P<0.001). Among the cardioembolic stroke patients, the frequency of prior anticoagulant use significantly increased from 15.6% in 2001-2002 to 24.8% in 2011-2012 (P<0.001). The frequency of prior antiplatelet use increased from 2001-2002 to 2007-2008 but decreased after 2007-2008. Among both cardioembolic and non-cardioembolic stroke patients, initial stroke severity at admission decreased over time, particularly after 2008.

CONCLUSIONS

In this Japanese study, the mean age of ischemic stroke onset increased, while the initial neurological severity at presentation decreased, over a 12-year period. (Circ J 2016; 80: 2033-2036).

Cerebral blood flow and metabolism associated with cerebral microbleeds in small vessel disease

OBJECTIVE

Cerebral microbleeds (CMBs), probably reflecting microangiopathy, have not yet sufficiently been examined in association with cerebral blood flow (CBF) and metabolism. We investigated the relationships between CMBs, and CBF and metabolism in symptomatic small vessel disease.

METHODS

We enrolled 22 patients with symptomatic small vessel disease without severe stenosis (>50 %) in major cerebral arteries. Volumes of white matter lesions (WMLs) and number of CMBs were assessed on images of fluid-attenuated inversion recovery and gradient-echo T2*-weighted magnetic resonance imaging, respectively. Patients were divided into two groups according to the median number of CMBs (group I <5, n = 10; group II ≥5, n = 12). Parametric images of CBF, cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction and cerebral blood volume were estimated using positron emission tomography and (15)O-labeled gases. The functional values in the cortex-subcortex, basal ganglia, and centrum semiovale were compared between the two groups.

RESULTS

Volumes of WMLs of group II were larger than those of group I (median: 38.4; range: 25.1-91.5 mL vs. median: 11.3; range: 4.2-73.4 mL, p = 0.01). In the centrum semiovale, the mean CBF of group II was significantly lower than that of group I (12.6 ± 2.6 vs. 15.6 ± 3.3 mL/100 g/min, p = 0.04). In the other regions, there were no significant differences in either CBF or CMRO2 between the two groups.

CONCLUSIONS

Our study indicated that increases in the number of CMBs with larger volumes of WMLs were associated with cerebral ischemia in the deep white matter in patients with symptomatic small vessel disease.

Abstract T P178: Cerebral Blood Flow and Metabolism Associated with Cerebral Microbleeds in Patients with Non-cardioembolic Stroke Without Major Cerebral Arterial Stenosis

Background and Purpose: Cerebral microbleeds (CMBs) are associated with not only higher age but also extensive white matter lesions (WMLs), indicating that CMBs could be a reflection of microangiopathy. CMBs have not yet been examined in association with cerebral blood flow (CBF) and metabolism. The purpose of this study was to clarify the relationships of CMBs with WMLs volume, and CBF and metabolism in patients with ischemic stroke.

Methods: We enrolled 19 patients who had past history of non-cardioembolic stroke without severe stenosis (>50%) in major cerebral arteries (69±7 years, 9 women). We measured WMLs volume and counted the number of CMBs on a 1.5-T magnetic resonance imaging (MRI) scanner. CBF, cerebral blood volume, oxygen extraction fraction and cerebral metabolic rate of oxygen were measured with 15 O-labeled gas positron emission tomography (PET). We set 36 regions of interest (ROIs) in the cortex-subcortex regions, basal ganglia and centra semiovale in each patient on MRI. MRI was superimposed on PET images and 4 parameters of each ROI were calculated.

Results: CMBs existed in 14 out of 19 patients (median 5; range 0-39). Patients were divided into 2 groups according to the number of CMBs; less than 5 as the group I (n=9) and 5 or more as the group II (n=10). WMLs volume of the group II was larger than that of the group I (median 38.4 with range of 25.1-91.5 vs. 10.0 with 4.2-73.4 ml, p=0.020). In the centra semiovale, CBF of the group II was significantly lower than that of the group I (12.5±2.5 vs. 15.7±3.5 ml/100g/min, p=0.031). In the other regions, there were no significant differences in all 4 parameters of PET between the 2 groups.

Conclusions: We showed that the increases in the number of CMBs could indicate cerebral ischemia in the deep white matter of patients with non-cardioembolic stroke without major cerebral arterial stenosis.

Abstract WMP75: Is Glycemic Control With Sliding Scale Insulin Therapy Safe For Diabetic Patients With Acute Ischemic Stroke?

Backgroundand Purpose: There is no established glycemic control for acute ischemic stroke. Patients’ outcomes may be deteriorated by strict glycemic control with sliding-scale insulin therapy (SSIT) via hypoglycemia. We aimed to investigate baseline characteristics, frequency of hypoglycemia and outcome in diabetic patients who received SSIT in acute ischemic stroke.

Methods: Consecutive ischemic stroke patients with diabetes mellitus (DM) admitted to our hospital within 7 days of onset from 2008 through 2010 were studied. DM was defined as having prior diabetic medications, fasting plasma glucose (PG) of 126mg/dl, 2-h PG of ≥200 mg/dl during a 75g OGTT, random PG of ≥200 mg/dl, or HbA1c (NGSP) of ≥6.5%. Physicians in charge decided whether the patient was treated with sliding scale insulin therapy (SSIT) at admission. Hypoglycemia was defined as having PG of ≤80 mg/dl during hospitalization. Favorable outcome was defined as mRS 0-1 at 3 months.

Results: Of a total 258 ischemic stroke patients with DM (193 men, 72 ± 10 yo), 130 (96 men, 71±10 yo) received SSIT (SSIT group) and the remaining 128 (97 men, 73±9 yo) did not (N group). Patients in the SSIT group more frequently took prior diabetic medication (72% vs 53%, p=0.001), had higher initial PG (199±85 mg/dl vs 156±78 mg/dl, p<0.001), higher HbA1c (7.8±1.9% vs 6.8±1.2%, p<0.001) and higher initial NIHSS [median 4 (IQR 2-7) vs. 3 (IQR 1-5), p=0.028] than those in the N group. Hypoglycemia tended to be more common (15% vs 7%, p=0.050) and favorable outcome tended to be less common (43% vs 54%, p=0.081) in the SSIT group than in the N group. In the SSIT group, 19 patients showing hypoglycemia were older (76±8 years vs 71±10 years, p=0.031), more frequently took prior diabetic medication (95% vs 68%, p=0.015), and had lower admission levels of PG (163±68 mg/dl vs 206±86 mg/dl, p=0.040) and HbA1c (6.9±1.3% vs 7.9±2.0%, p=0.035) than those in the remaining 111 patients without hypoglycemia.

Conclusions: Acute ischemic stroke patients with prior diabetic medication, poor glycemic control before onset and severer stroke symptom often received SSIT. Hypoglycemia was found in one seventh of patients treated with SSIT. We have to be careful especially when aged patients or diabetic medication users receive SSIT.

Immunostaining of thymidylate synthase and p53 for predicting chemoresistance to S-1/cisplatin in gastric cancer

High expression of thymidylate synthase (TS) and inactivation of p53 are allegedly associated with chemoresistance. The authors evaluated TS and p53 expression in gastric cancer treated with neoadjuvant S-1/cisplatin chemotherapy. Paraffin sections of pretreatment biopsy and surgical specimens from 41 gastric cancers were immunostained for TS and p53 protein after appropriate antigen retrieval. Fifty-one cases without neoadjuvant chemotherapy were also studied. In the pretreatment biopsies, high expression of TS was seen in 8% of the histologic responders, in 28% of the nonresponders and in 31% of the controls. High expression of p53 was observed in 56% of the nonresponders, but in 8% of the responders and in 29% of the controls (P<0.01 and P<0.05, respectively). The TS- and/or p53-high phenotype was seen in 76% of the nonresponders and in 54% of the controls, but in 8% of the responders (P<0.0001 and P<0.005, respectively). The data of the surgical specimens were consistent with those of the pretreatment biopsies. These results suggest that immunostaining for TS and p53 protein is useful for pretreatment selection of gastric cancer patients unresponsive to S-1/cisplatin chemotherapy.

Phosphorylation sites of myelin basic protein by a catalytic fragment of non-receptor type protein-tyrosine kinase p72syk and comparison with those by insulin receptor kinase

Myelin basic protein has been used as a model substrate for determination of substrate recognition motif of various protein kinases. In this report phosphorylated sites of bovine brain myelin basic protein were studied with a catalytic fragment of protein-tyrosine kinase p72syk. Three of four tyrosine residues in myelin basic protein were phosphorylated by this kinase. Major phosphorylated site was 134Y and minor phosphorylated sites were 68Y and 127Y. As the phosphorylation site by p56lck was only 68Y, the recognition motif of p72syk was quite different from that of p56lck. Furthermore, the fact that elution pattern on HPLC of the phosphopeptides obtained by insulin receptor kinase was different from that by p72syk suggested that the recognition motif of p72syk was also different from that of insulin receptor kinase. These results may suggest that each protein-tyrosine kinase has a specific substrate recognition motif.

Identification of the phosphorylation sites of H2B histone by a catalytic fragment of p72syk from porcine spleen

Phosphorylated sites of calf thymus H2B histone were investigated with a catalytic fragment of 72 kDa protein-tyrosine kinase (p72syk). Three of five tyrosine residues in H2B histone can be phosphorylated by this kinase. In this analysis, H2B histone was thoroughly phosphorylated in vitro with [gamma-32P]ATP and the kinase, and then digested with a lysylendopeptidase. The resulting radioactive phosphopeptides were separated by a reverse-phase column on high performance liquid chromatography. Subsequent sequential Edman degradation of the purified phosphopeptides revealed that 40Y, 83Y and 121Y were phosphorylated. 121Y is the major phosphorylated residue in H2B histone. No phosphorylation was detected in 37Y and 42Y. Although the consensus sequence was not defined from these analyses, our data suggest that higher-order structure(s) in addition to primary one may participate in recognition of H2B histone by this protein kinase.

Possible endogenous substrate proteins for cytosolic protein-tyrosine kinase from porcine spleen

1. Endogenous phosphate acceptor proteins by cytosolic protein-tyrosine kinase from porcine spleen (CPTK-40) were studied using subcellular fractions of porcine spleen and supernatant fraction of rat various tissues. 2. At least 13 phosphate acceptor proteins ranging from 94 to 26 kDa were observed in all but mitochondrial subcellular fractions. 3. Among the supernatant fraction of rat tissues, brain, testis and spleen contained many phosphate acceptor proteins. 4. The most heavily phosphorylated band of around 55 kDa which was commonly recognized among various tissues was confirmed as tubulin by the immunoreactivity with anti-tubulin antibody. 5. The results obtained in this paper indicate that CPTK-40 has the potential to catalyze the phosphorylation of numerous endogenous proteins including tubulin.

Phospholipids differently modulate the activity of cytosolic protein-tyrosine kinase from porcine spleen

Effect of membrane phospholipids on the activity of cytosolic protein-tyrosine kinase from porcine spleen (CPTK-40) has been studied. Using poly(Glu Na, Tyr)4:1 as a substrate, phosphatidylethanolamine, phosphatidylcholine and phosphatidylserine had stimulatory effects on that phosphorylation activity, however phosphatidic acid had inhibitory and phosphatidylinositol had no effects. Similar results were obtained using[Val5]angiotensin II as a substrate. On the other hand using basic protein (H2B histone and myelin basic protein) as substrates, phosphatidic acid stimulated the activity of CPTK-40, while phosphatidylinositol inhibited the activity. Phosphatidylethanolamine, phosphatidylcholine and phosphatidylserine caused different effect on the activity of CPTK-40 depending on the substrate employed. However using acidic protein (tubulin and casein) as substrates, the activity of CPTK-40 was neither stimulated nor inhibited by any phospholipids. These results suggest that phospholipids may modulate the activity of CPTK-40.

Functional specificity of guanosine 3':5'-monophosphate-dependent and adenosine 3':5'-monophosphate-dependent protein kinases from silkworm

Adenosine 3':5'-monophosphate-dependent protein kinase partially purified from silkworm pupae shows identical functional activities with those of mammalian protein kinases; the insect and mammalian kinases are completely exchangeable in the phosphorylation of muscle glycogen phosphorylase kinase and glycogen synthetase resulting in the activation and inactivation of the respective enzymes. In contrast, guanosine 3':5'-monophosphate-dependent protein kinase obtained from the same organism is totally inactive in this role and phosphorylates different, mainly seryl and some threonyl, residues of acceptor proteins. Substrates of the latter kinase intimately involved in the regulation of biological processes have remained unknown.