Accelerometer-based gait characteristics and their discrimination of gait independence in inpatients with subacute stroke

BACKGROUND

Gait analysis using inertial measurement devices can identify multifaceted gait disorders after a stroke. Although the usefulness of gait assessment using inertial measurement devices has been reported, its accuracy in discriminating gait independence in patients hospitalized for subacute stroke has not yet been validated.

RESEARCH QUESTION

Can trunk acceleration indices discriminate between dependent and independent walking in patients with subacute stroke?

METHODS

Thirty-five patients with subacute stroke (mean ± standard deviation, 75.5 ± 9.8 years, 19 males), who were able to understand instructions, had a premorbid modified Rankin scale <3, and were able to walk 16 m straight ahead under supervision were included. The stride regularity, harmonic ratio, and normalized root mean square of trunk accelerations were measured in three directions (mediolateral, vertical, and anterioposterior) during comfortable walking. The Functional Ambulation Categories were used as the dependent variable to classify the patients into two groups (dependent and independent walking groups), and each trunk acceleration index was used as the independent variable to calculate the area under the curve using receiver operating characteristic curves.

RESULTS

Twelve patients were in the dependent group and 23 were in the independent group. The normalized root mean square in both the mediolateral and vertical directions were excellent discriminators of walking independence, with an area under the curve greater than 0.8. The cutoff values (sensitivity/specificity) were 2.20 m2/s2 (0.783/0.833) and 2.82 m2/s2 (0.739/0.833), respectively.

SIGNIFICANCE

The magnitude of vertical and lateral acceleration during gait in patients with subacute stroke, has excellent accuracy in discriminating between dependent and independent gaits. The results of this study will be useful for inexperienced clinicians working with stroke patients presenting with gait disturbances to accurately determine gait independence based on objective data.

Clinical prediction rules for multi surfaces walking independence using the Berg Balance Scale or Mini-Balance Evaluation Systems Test in persons with stroke

BACKGROUND

A Clinical prediction rule (CPR) for determining multi surfaces walking independence in persons with stroke has not been established.

OBJECTIVES

To develop a CPR for determining multi surfaces walking independence in persons with stroke.

METHODS

This was a multicenter retrospective analysis of 419 persons with stroke. We developed a Berg Balance Scale (BBS)-model CPR combining the BBS, comfortable walking speed (CWS) and cognitive impairment, and a Mini-Balance Evaluation Systems Test (Mini-BESTest)-model CPR combining the Mini-BESTest, CWS, and cognitive impairment. A logistic regression analysis was conducted with multi surfaces walking independence as the dependent variable and each factor as an independent variable. The identified factors were scored (0, 1) based on reported cutoff values. The CPR's accuracy was verified by the area under the curve (AUC). We used a bootstrap method internal validation and calculated the CPR's posttest probability.

RESULTS

The logistic regression analysis showed that the BBS, CWS, and cognitive impairment were factors in the BBS model, and the Mini-BESTest was a factor in the Mini-BESTest model. The CPRs were 0-3 points for the BBS model and 0-1 points for the Mini-BESTest model. The AUCs (bootstrap mean AUC) of the CPR score were 0.89 (0.90) for the BBS model and 0.72 (0.72) for the Mini-BESTest model. The negative predictive value (negative likelihood ratio) was 97% (0.054) for CPR scores < 2 for the BBS model and 94% (0.060) for CPR scores < 1 for the Mini-BESTest model.

CONCLUSIONS

The CPR developed herein is useful for determining multi surfaces walking independence.

Item distribution of the Berg Balance Scale in older adults with Hip fracture: a Rasch analysis

INTRODUCTION

Balance impairment occurs after a hip fracture, but the characteristics of the impairment are not clear.

OBJECTIVE

To investigate the uni-dimensionality, fit statistics, and item difficulty of the Berg Balance Scale (BBS) in older adults with hip fracture by conducting a Rasch analysis.

METHODS

This was an observational cross-sectional study. The 254 participants were all ≥ 65 years old and had been hospitalized for rehabilitation after a unilateral hip fracture incurred during a fall. We collected their BBS scores at the time of hospital discharge and conducted a Rasch analysis to examine the uni-dimensionality, fit statistics, and item difficulty.

RESULTS

The principal component analysis (PCA) of the Rasch model demonstrated that the BBS is uni-dimensional. The information-weighted mean square (MnSq) fit statistic was within the range of fit criteria for all items. The underfit item of the outlier-sensitive MnSq fit statistics was "Standing unsupported eyes closed" with the MnSq of 2.06. The difficult items were in order of logits: "Standing on one leg" (logits = 4.01); "Step tool" (logits = 2.74); and "Turn 360°" (logits = 2.61).

CONCLUSION

The BBS is uni-dimensional and conforms with the Rasch model. The BBS most difficult items for older adults with a hip fracture required one-legged support and dynamic balance.

Minimal detectable change in inertial measurement unit-based trunk acceleration indices during gait in inpatients with subacute stroke

Gait analysis using inertial measurement units (IMU) provides a multifaceted assessment of gait characteristics, but minimal detectable changes (MDC), the true change beyond measurement error, during gait in patients hospitalized with subacute stroke has not been clarified. This study aimed to determine the MDC in IMU-based trunk acceleration indices during gait in patients hospitalized with subacute stroke. Nineteen patients with subacute stroke (mean ± SD, 75.4 ± 10.9 years; 13 males) who could understand instructions, had a pre-morbid modified Rankin Scale < 3 and could walk straight for 16 m under supervision were included. As trunk acceleration indices, Stride regularity, harmonic ratio (HR), and normalized root mean square (RMS) during gait were calculated on three axes: mediolateral (ML), vertical (VT), and anterior-posterior (AP). MDC was calculated from two measurements taken on the same day according to the following formula: MDC = standard error of measurement × 1.96 × 2. The MDCs for each trunk acceleration index were, in order of ML, VT, and AP: 0.175, 0.179, and 0.149 for stride regularity; 0.666, 0.741, and 0.864 for HR; 4.511, 2.288, and 2.680 for normalized RMS. This finding helps determine the effectiveness of rehabilitation interventions in the gait assessment of patients with stroke.

Minimal important change in the Berg Balance Scale in older women with vertebral compression fractures: A retrospective multicenter study

BACKGROUND

Vertebral compression fractures, which are commonly associated with older age and osteoporotic fractures, have an increased risk of re-fracture. Therefore, improving balance is important to prevent falls. The minimal important change (MIC) has been recommended for interpreting clinically meaningful changes in rating scales. The MIC of the Berg Balance Scale (BBS) for use in older women with vertebral compression fractures has not been established.

OBJECTIVE

To identify the MIC of the BBS that can be used in older women with vertebral compression fractures using predictive modeling methods and the receiver-operating characteristic (ROC)-based method.

DESIGN

A retrospective longitudinal multicenter study.

PATIENTS

Sixty older women (mean age ± standard deviation: 84.1 ± 7.0 years) with vertebral compression fractures who were unable to ambulate independently on a level surface.

METHODS

A change of one point in the Functional Ambulation Category (FAC) was used as an anchor to calculate the MIC of the BBS based on the change between admission and discharge. We calculated the MIC for the women whose FAC score improved by ≥1 point. We used three anchor-based methods to examine the MIC: the ROC-based method (MICROC ), the predictive modeling method (MICpred ), and the MICpred -based method adjusted by the rate of improvement and reliability of transition (MICadj ).

RESULTS

Thirty-nine women comprised the "important change" group based on their FAC score improvement. In this group, the MICROC (95% confidence interval [CI]) value of the BBS was 10.0 points (5.5-15.5), with an area under the curve of 0.71. The MICpred (95% CI) value was 9.7 (8.1-11.0), and the MICadj (95% CI) was 7.0 (5.5-8.5) points.

CONCLUSION

For women with vertebral compression fractures who are unable to ambulate independently, a 7.0-point improvement in the BBS score may be a useful indicator for reducing the amount of assistance required for walking.

Predictive discriminative accuracy of walking abilities at discharge for community ambulation levels at 6 months post-discharge among inpatients with subacute stroke

[Purpose] This study aimed to compare the predictive accuracy of walking ability at discharge among subacute stroke inpatients at 6 months post-discharge in terms of community ambulation level and establish optimal cut-off values. [Participants and Methods] This prospective observational study included 78 patients who completed follow-up assessments. Patients were classified into three groups based on the Modified Functional Walking Category (household/most limited community walkers, least limited community walkers, and unlimited community walkers) obtained by telephone survey at 6 months post-discharge. Predictive accuracy and cut-off values for discriminating among groups were calculated from 6-minute walking distance and comfortable walking speed measured at the time of discharge using receiver operating characteristic curves. [Results] Between household/most limited and least limited community walkers, 6-minute walking distance and comfortable walking speed offered similar predictive accuracy (area under the curve, 0.6-0.7), with cut-off values of 195 m and 0.56 m/s, respectively. Between least limited and unlimited community walkers, the areas under the curve were 0.896 for 6-minute walking distance and 0.844 for comfortable walking speed, with cut-off values of 299 m and 0.94 m/s, respectively. [Conclusion] Walking endurance and walking speed among inpatients with subacute stroke provided superior predictive accuracy for unlimited community walkers at 6 months post-discharge.

Relationship between gait regularity and harmony, and gait speed at discharge in inpatients with subacute stroke

[Purpose] Accelerometry indices are a promising and simple method to quantify gait stability. However, the long-term relationship between gait stability and walking ability in patients with stroke has not been fully investigated. The purpose of this study was to longitudinally examine the relationship between gait regularity and harmony at admission and gait speed at discharge in inpatients with subacute mild stroke. [Participants and Methods] Sixteen patients with subacute stroke (median age, 69.5 years [1st-3rd interquartile range, 58.0-73.8 years]; 13 males) were enrolled in the study. A Spearman's rank correlation coefficient was calculated for step regularity, stride regularity, the harmonic ratio at admission, and the walking speed at discharge. We also calculated the partial rank order correlation, controlling for balance ability. [Results] The vertical step regularity, harmonic ratio, and anterior-posterior harmonic ratio were all positively correlated with the walking speed at discharge. Positive correlations with vertical step regularity and harmonic ratio were found in partial rank order correlations when controlled for balance ability. [Conclusion] Vertical step regularity and gait harmony had predictive validity for discharge gait speed in patients with subacute stroke.

The minimal clinically important difference of the mini-balance evaluation systems test in patients with early subacute stroke

BACKGROUND

There is insufficient evidence regarding the minimal clinically important difference (MCID) of the Mini-Balance Evaluation Systems Test (Mini-BESTest).

OBJECTIVE

To determine the MCID of the Mini-BESTest in patients with early subacute stroke.

PATIENTS AND METHODS

In this prospective cohort study, the Mini-BESTest score of 50 patients with stroke was obtained within 1 week of their admission, their Mini-BESTest and Global Rating of Change Scale (GRCS) scores were obtained at discharge. The GRCS scores were reported by both the patients and their physical therapists. We evaluated the correlation between the Mini-BESTest change scores and the GRCS by determining Spearman's rank correlation coefficient. The MCID was calculated using 0.5× standard deviation (SD) for the distribution method and the change difference and receiver operating curve (ROC) for the anchor method.

RESULTS

The mean (SD) number of days between evaluations was 15.4 (4.8), and the Mini-BESTest score at admission was 17.7 (5.2) and 23.1 (3.5) at discharge. The correlation between the GRCS and the change in the Mini-BESTest score was 0.28 (p = .04) for the patients and 0.54 (p < .001) for the therapists. The MCID based on the distribution method was 3 points for 0.5× SD. The MCID values based on the anchor method were 2.3 for the change difference and 0.5 for the ROC in the patient-rated GRCS, and 4.2 for the change difference and 4.5 for the ROC in the physical therapist-rated GRCS.

CONCLUSIONS

The MCID based on the anchor method was 4.2-4.5 points, and the MCID based on the distribution method was 2.3 points.

Minimal clinically important difference of the Berg Balance Scale and comfortable walking speed in patients with acute stroke: A multicenter, prospective, longitudinal study

OBJECTIVE

To determine the minimal clinically important difference between the Berg Balance Scale and comfortable walking speed in acute-phase stroke patients.

DESIGN

Multicenter, prospective, longitudinal study.

SETTING

Inpatient acute stroke rehabilitation.

SUBJECTS

Seventy-five patients with acute stroke, mean (SD) age 71.7 (12.2) years.

INTERVENTION

Inpatients with acute stroke were assessed with the Berg Balance Scale and comfortable walking speed before and after rehabilitation. Physiotherapy was conducted to improve balance and gait over a 2-week period: an average of 40 min/day on weekdays and 20 min/day on weekends and holidays.

MAIN MEASURES

The patients' Berg Balance Scale, comfortable walking speed, Global Rating of Change scale (patient-rated and physiotherapist-rated), and motor score of the Functional Independence Measure were obtained. Minimal clinically important differences were estimated using both anchor- (receiver operating characteristic curves and change difference) and distribution-based approaches (minimal detectable change and 0.5× the change score [SD]).

RESULTS

The baseline scores were 31.2 (18.9) for the Berg Balance Scale and 0.79 (0.35) m/s for comfortable walking speed. The minimal clinically important difference in the Berg Balance Scale was 6.5-12.5 points by the anchor-based approach and 2.3-4.9 points by the distribution-based approach. The minimal clinically important difference in comfortable walking speed was 0.18-0.25 m/s by the anchor-based and 0.13-0.15 m/s by the distribution-based approach.

CONCLUSIONS

A change of 6.5-12.5 points in the Berg Balance Scale and 0.18-0.25 m/s in the comfortable walking speed is required in these measurements' anchor-based minimal clinically important differences to be beyond measurement error, and to be perceptible by both patients and clinicians.

Relationship of the brief-balance evaluation systems test with physical functioning and activities of daily living: A cross-sectional study among hospitalized acute stroke patients

BACKGROUND: The Brief-Balance Evaluation Systems Test (Brief-BESTest) has the potential to be used effectively for interventions on specific balance components. However, it has not been utilized for acute stroke cases. OBJECTIVE: This study determined the characteristics of the distribution of the Brief-BESTest scores of patients who suffered acute stroke and examined its relationship with physical function and activities of daily living ability. METHODS: The Brief-BESTest, sub-items of Stroke Impairment Assessment Set (SIAS), and Functional Independence Measure (FIM) were conducted among 41 hospitalized acute stroke patients (71.3±9.5 years, 32 males). The skewness of the Brief-BESTest and Spearman’s rank correlation (ρ) between Brief-BESTest, SIAS, and FIM were analyzed. RESULTS: The skewness of the total score of the Brief-BESTest was -0.038. There were no ceiling or floor effects. The total score of the Brief-BESTest had a weak positive correlation with the SIAS lower extremity motor function (ρ= 0.457) and muscle tone (ρ= 0.374), and the total score on FIM (ρ= 0.365). Each sub-item of the Brief-BESTest was associated with different physical functions. CONCLUSIONS: The Brief-BESTest was unaffected by floor and ceiling functions among hospitalized acute stroke patients, and different physical functions were associated with each balance component.

Cut-off values and sub-items of the Berg Balance Scale for walking-aid use in hospitalized older adults with a hip fracture: a retrospective analysis

OBJECTIVE

To identify the Berg Balance Scale (BBS) values that can be used to discriminate the use of a walking aid and the BBS sub-items that reveal the differences in the use of walking aids among hospitalized older adults with a hip fracture.

METHODS

The cases of 77 older adults (age 80.8 ± 7.5 years) with a hip fracture who were able to walk independently in the hospital were retrospectively analyzed. A receiver operating characteristic curve (AUC) analysis was used to identify BBS scores that optimized the identification of subjects with different levels of aids. The BBS sub-items identifying differing among the walking aids were identified by a classification and regression tree analysis.

RESULTS

The BBS scores were highest for no aid, a cane, and a walker, in that order. The ability to walk without an aid and the ability to walk without a walker showed moderate AUCs (0.824 and 0.865) with cutoff values of 51.5 and 45.5 points, respectively. The sub-items identified were Turning 360° (4 vs. < 4 points) as the best discriminator for using/not using a cane and Stool Stepping (≥ 2 vs. < 2 points) for using a cane or walker.

CONCLUSION

The BBS is useful for determining whether to discontinue the use of a walker in individuals with a hip fracture.

Development of Cut-off Values on the Berg Balance Scale for Predicting Walking Independence in Older Adults with Hip Fracture

Objectives:

The aim of the current study was to identify a cut-off value for predicting walking independence at discharge in older adults with hip fracture based on their Berg Balance Scale (BBS) score at admission to a convalescent rehabilitation ward.

Methods:

This was a retrospective, multicenter, observational study of 187 older adults with hip fractures (mean age 83.7, range 66–97 years). Data was collected on the patients’ age, sex, treatment, and physical function evaluation. An ordinal logistic regression analysis was used to identify predictors associated with the degree of independence in walking at discharge. Receiver operating characteristic curves were used to estimate cut-off values to predict independent and supervised walking at discharge based on the BBS score at admission. The accuracy of the classification was assessed using the area under the curve (AUC).

Results:

The BBS score at admission was a significant factor predicting the degree of walking independence at discharge (odds ratio = 1.09, 95%CI: 1.06–1.11). The cut-off values of the BBS score at admission for predicting independent walking and supervised walking at discharge were 28 points (AUC = 0.76, 95%CI: 0.69–0.83) and 21 points (AUC = 0.84, 95%CI: 0.77–0.91), respectively.

Conclusions:

The BBS scores of older adults with hip fracture on admission to a rehabilitation ward are useful for predicting the degree of independence in walking at discharge and can help to structure therapy according to the predicted degree of independence.

Minimal clinically important difference of the Berg Balance Scale score in older adults with hip fractures

PURPOSE

The minimal clinically important difference (MCID) is the smallest clinically significant difference in treatment identified as crucial to the patient. There is no known MCID for the Berg Balance Scale (BBS), which measures balance function in patients with hip fractures. We aimed to calculate the MCID of the BBS in older adults with hip fractures.

MATERIALS AND METHODS

This is a retrospective multicenter clinical study that included 187 older adults with hip fractures. MCID was calculated using functional ambulation categories (FACs), which were used as anchors for the change in BBS scores between admission and discharge. MCID was calculated as an improvement for more than one point and as a substantial change for improvement for more than two points in the FAC.

RESULTS

MCID of the BBS was 11.5 points and that of the substantial change was 18.5 points, with an area under the curve of 0.76 and 0.81, respectively.

CONCLUSIONS

MCID for the BBS was 11.5 points in older adults with hip fractures. In addition, an improvement of more than 18.5 points in BBS can be considered a substantial change. These values may be useful in determining meaningful balance function improvement.Implications for rehabilitationHip fractures are a common injury for the older adults, and improvement in gait function has a bearing on prognosis.The effectiveness of meaningful rehabilitation is possible to determine by clarifying the minimal clinically important difference in balance function, which is important for the acquisition of gait.An improvement of 11.5 points or more on the Berg Balance Scale in an older adult with a hip fracture is considered a meaningful effect.

The minimal clinically important difference in Berg Balance Scale scores among patients with early subacute stroke: a multicenter, retrospective, observational study

Background: Balance dysfunction is common in stroke patients. The Berg Balance Scale (BBS) is useful for evaluating the balance function of stroke patients, and it can estimate the minimal clinically important difference (MCID) in balance. BBS scores differ among stroke patients depending on whether they require walking assistance. The MCID should thus be estimated separately for patients who require assistance and those who do not.Objectives: To estimate the MCID of individuals who have had an early subacute stroke and require a walking aid and those who do not, to assist the clinical determination of the effectiveness of therapy.Methods: This was a retrospective clinical analysis of 80 early subacute stroke patients. We estimated the MCID by using the Functional Ambulation Categories (FAC) as anchors for changes in BBS scores during a 1-month period. The MCID was estimated based on a cutoff score for separating the patients who achieved a FAC change ≥1 point on receiver operator characteristic curves. The area under the curve (AUC) was used to measure the discrimination accuracy. The MCID was estimated for the patients who needed walking assistance and those who did not.Results: The estimated MCID of BBS scores in the assisted-walking group was 5 points and the AUC was 0.84 (p < .01); the corresponding values in the unassisted-walking group were 4 points and 0.62 (p = .26).Conclusions: For early subacute stroke patients who require assistance to walk, a 5-point improvement in the BBS score is a useful indicator for reducing the amount of assistance.

High expression of ABCG2 induced by EZH2 disruption has pivotal roles in MDS pathogenesis

Both proto-oncogenic and tumor-suppressive functions have been reported for enhancer of zeste homolog 2 (EZH2). To investigate the effects of its inactivation, a mutant EZH2 lacking its catalytic domain was prepared (EZH2-dSET). In a mouse bone marrow transplant model, EZH2-dSET expression in bone marrow cells induced a myelodysplastic syndrome (MDS)-like disease in transplanted mice. Analysis of these mice identified Abcg2 as a direct target of EZH2. Intriguingly, Abcg2 expression alone induced the same disease in the transplanted mice, where stemness genes were enriched. Interestingly, ABCG2 expression is specifically high in MDS patients. The present results indicate that ABCG2 de-repression induced by EZH2 mutations have crucial roles in MDS pathogenesis.

Removing arsenic from groundwater in Cambodia using high performance iron adsorbent

In Cambodia, groundwater has been contaminated with arsenic, and purification of the water is an urgent issue. From 2010 to 2012, an international collaborative project between Japan and Cambodia for developing arsenic-removing technology from well water was conducted and supported by the foundation of New Energy and Industrial Technology Development Organization, Japan. Quality of well water was surveyed in Kandal, Prey Veng, and Kampong Cham Provinces, and a monitoring trial of the arsenic removal equipment using our patented amorphous iron (hydr)oxide adsorbent was performed. Of the 37 wells surveyed, arsenic concentration of 24 exceeded the Cambodian guideline value (50 μg L(-1)), and those of 27 exceeded the WHO guideline for drinking water (10 μg L(-1)). Levels of arsenic were extremely high in some wells (>1,000-6,000 μg L(-1)), suggesting that arsenic pollution of groundwater is serious in these areas. Based on the survey results, 16 arsenic removal equipments were installed in six schools, three temples, two health centers, four private houses, and one commune office. Over 10 months of monitoring, the average arsenic concentrations of the treated water were between 0 and 10 μg L(-1) at four locations, 10-50 μg L(-1) at eight locations, and >50 μg L(-1) at four locations. The arsenic removal rate ranged in 83.1-99.7%, with an average of 93.8%, indicating that the arsenic removal equipment greatly lower the risk of arsenic exposure to the residents. Results of the field trial showed that As concentration of the treated water could be reduced to <10 µg L(-1) by managing the As removal equipment properly, suggesting that the amorphous iron (hydr)oxide adsorbent has high adsorbing capacity for As not only in the laboratory environment but also in the field condition. This is one of the succeeding As removal techniques that could reduce As concentration of water below the WHO guideline value for As in situ.

Safety and efficacy of water-in-oil-in-water emulsion vaccines containing Newcastle disease virus haemagglutinin-neuraminidase glycoprotein

Subunit vaccines containing haemagglutinin-neuraminidase (HN) glycoprotein of Newcastle disease virus (NDV), formulated as water-in-oil-in-water (W/O/W) emulsions, were prepared. First, the suitable constituents of a W/O/W emulsion adjuvant were investigated with polyvalent vaccines using NDV, infectious bronchitis virus and Haemophilus paragallinarum. The W/O/W emulsion adjuvant, composed of the antigen in phosphate-buffered saline (PBS), liquid paraffin, squalene, diglyceryl monooleate, polysorbate 80 and PBS in a 30:25:10:5:2:28 ratio, induced a good antibody response with less adverse local reactions. HN protein of NDV was expressed by an improved baculovirus expression vector, a hybrid nucleopolyhedrovirus (HyNPV) between Autographa californica NPV and Bombyx mori NPV,and was prepared from silkworm pupae infected with the recombinant baculovirus, HyNPV-HN. Then, the W/O/W emulsion vaccine containing HN protein was prepared using the aforementioned constituents. Chickens showed 100, 100 and 80% protection against challenge exposure to virulent NDV at 4 weeks after vaccination with W/O/W emulsion vaccines containing 30, 6 and 3% of HyHPV-HN-infected pupae, respectively. The vaccines containing HN protein did not induce adverse local reactions at the site of injection. The subunit vaccine for NDV containing HN protein expressed in the recombinant baculovirus-infected pupae, formulated as a W/O/W emulsion vaccine composed of the antigen in PBS, liquid paraffin, squalene, diglyceryl monooleate, polysorbate 80 and PBS in a 30:25:10:5:2:28 ratio, was therefore found to be safe and effective.

An incidentally discovered small and asymptomatic para-aortic paraganglioma

Preoperative diagnosis of asymptomatic paraganglioma is difficult due to the lack of specific symptoms. In this report, we present a rare case of a small and asymptomatic para-aortic paraganglioma. A 34-year-old woman who complained of back pain was admitted for further examination. No abnormal findings were observed on physical or laboratory examinations. An abdominal CT scan and an abdominal MRI incidentally noted a mass about 3 cm in diameter adjacent to the right edge of the inferior vena cava. The following aortic angiography showed the tumor with a feeding artery diverting directly from the aorta. The tumor was completely resected by laparotomy. The resected tumor, 3 x 3 x 3 cm in size, was soft, dark-reddish and encapsulated. Immunohistochemical examinations showed that it was positive for neuron-specific enolase, chromogranin A and adrenocorticotropin. Under these findings, the diagnosis of para-aortic paraganglioma was determined. Seven years after the operation, she remains asymptomatic and free of disease.

Methylenetetrahydrofolate reductase C677T is not associated with expression of pyrimidine metabolic enzyme genes in colorectal cancer

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may influence the chemosensitivity of colorectal cancers to fluorouracil (5-FU) by increasing intracellular 5,10-methylenetetrahydrofolate. The effect of this polymorphism on the expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) and thymidine phosphorylase (TP) in colorectal cancer was investigated. The MTHFR C677T polymorphism was analysed and TS, DPD, OPRT and TP mRNA expression was measured in tumour and adjacent normal mucosal tissue. In all patients, the genotypes of the tumour and normal tissues were identical. No differences were found in the expression of TS, DPD or TP mRNA by genotype in either tumour or normal tissue. Although the OPRT mRNA level in tumour tissue was not associated with the genotype, normal mucosa with the TT genotype showed a significantly higher OPRT mRNA level than mucosa with other genotypes. The MTHFR C667T polymorphism is not associated with intratumoural expression of TS, DPD, OPRT or TP.

Effects of a kappa-receptor agonist U-50488 on bulbar respiratory neurons and its antagonistic action against the mu receptor-induced respiratory depression in decerebrate cats

The function of kappa receptor-mechanisms in bulbar respiratory network was investigated in decerebrate cats. Intravenous injection of U-50488 (0.3-3.0 mg/kg) dose-dependently decreased the phrenic nerve discharge and shortened inspiration and expiration. U-50488 caused hyperpolarization, and decreased input resistance and the action potential discharge in respiratory neurons. The effects of U-50488 were antagonized by nor-binaltorphimine. DAMGO (0.3 mg/kg, i.v.) decreased the phrenic discharge and prolonged inspiration and expiration. U-50488 partially reversed the respiratory depression induced by DAMGO. These results suggest that the activation of K receptors by itself depresses the central respiratory activity, while it opposes the mu receptor-mediated respiratory depression.

Treatment of ruptured hepatocellular carcinoma

BACKGROUND

The problem of whether surgical or conservative treatment is indicated for ruptured hepatocellular carcinoma (HCC) has not been analyzed from the viewpoint of long-term development of hepatitis viral infection from liver fibrosis to liver cirrhosis. Although transcatheter arterial embolization (TAE) for hemostasis followed by two-stage hepatectomy has been established as the best treatment for ruptured HCC, there still remain difficulties in the treatment of some patients.

METHODS

Twelve patients with ruptured HCC who were surgically or conservatively treated were retrospectively analyzed in terms of modality of treatment, liver function, extension of HCC, complications, survival rate, and cause of death.

RESULTS

Tumor rupture can occur either in the early phase or in the terminal phase during the development from liver fibrosis to liver cirrhosis, while tumor rupture occurs at the advanced stage in terms of HCC extension. TAE for emergent hemostasis or prevention of re-bleeding was performed in ten patients, while TAE was contraindicated in one patient and emergent laparotomy for hemostasis was performed in one patient. In four patients, elective extended surgical resection was performed, because liver function was evaluated as clinical stage 1 according to the General rules for the clinical and pathological study of primary liver cancer of the Liver Cancer Study Group of Japan. In seven patients, conservative or medical treatment was selected, because liver function was evaluated as poor. The surgically treated group, who could tolerate extensive operation, survived longer than the conservatively treated group.

CONCLUSIONS

While TAE remains the best method to employ for hemostasis, it still has limitations. Hence, we should be mindful of other possible modalities for hemostasis and their outcomes. Rupture of HCC at an early phase in the development of liver fibrosis is a good indication for elective surgical treatment and should be distinguished from rupture in the terminal phase of liver cirrhosis, which should be treated conservatively. Although elective surgical treatment can be performed in selected patients, tumor size and location of HCC, in addition to liver function, should be taken into consideration.

Glutamic acid decarboxylase-immunoreactivity of bulbar respiratory neurons identified by intracellular recording and labeling in rats

To distinguish the GABAergic neuron in the ventral respiratory group (VRG) of rats, immunohistochemical staining of glutamic acid decarboxylase (GAD) was performed in neurons that had been individually identified by in vivo intracellular recording and labeling with neurobiotin. A total of five types of respiratory neurons were identified and labeled; augmenting inspiratory (aug-I, n=12), decrementing or early inspiratory (early-I, n=3), inspiration-expiration phase spanning or late inspiratory (late-I, n=3), decrementing expiratory or postinspiratory (PI, n=8), and augmenting or stage 2 expiratory (E2, n=3). In addition, expiration-inspiration phase-spanning or pre-inspiratory neurons (pre-I, n=2) were recorded, but not labeled. The membrane potential trajectory of each neuron type resembled that previously described in cat, suggesting a comparable neuronal organization between the two species. According to the axonal arborization, those labeled neurons were further classified as propriobulbar (6 aug-I, all early-I, all late-I, and 3 PI), bulbospinal (2 aug-I and all E2) and cranial-motor neurons (4 aug-I and 5 PI). GAD-immunoreactivity was consistently detected in the propriobulbar neurons, while it was not seen in cranial-motor and bulbospinal neurons. In addition, GAD-immunoreactive varicosities were found surrounding the somatic and dendritic surface of all labeled neurons. The present results illustrate that the propriobulbar types of early-I, aug-I, late-I and PI neurons are GABAergic inhibitory neurons and virtually all types of respiratory neurons receive GABAergic inputs in the rat's VRG.

Extreme discrepancy between macroscopic diagnosis and pathological findings of gallbladder cancer treated by hepatopancreatoduodenectomy

Diagnosis of gallbladder cancer in terms of invasion depth and spread is an important factor in determining cumulative survival after surgical treatment. However, diagnostic methods available at present occasionally fail to judge staging correctly. We report a case of gallbladder cancer which showed extreme discrepancy between the preoperative macroscopic and imaging diagnosis (positive direct invasion to the liver and invasion to the bile duct and duodenum through the serosal layer; S3, Hinf3, Binf2, and stage IV by the Japanese Society of Biliary Surgery classification) and the pathological findings (limited in vasion within the subserosal layer; ss, hinf0. binf0, and stage II). This discrepancy allowed us to perform curative treatment by hepatopancreatoduodenectomy, including extended right lobectomy of the liver, external bile duct resection, resection of the mesocolon, and lymph node dissection. Surgeons should aim for curability of advanced gallbladder cancer by radical resection until accurate methods for the preoperative diagnosis of cancer spread are available, because the clinical picture may be modified by inflammatory changes.

Induction of hepatocellular carcinoma with high metastatic potential in WS/Shi rats: discovery of an inbred strain highly susceptible to the liver carcinogen N-nitrosomorpholine

We investigated the susceptibility of three inbred strains of rats to the hepatocarcinogen, N-nitrosomorpholine (NNM), to establish a spontaneous metastatic model of hepatocellular carcinoma (HCC). WS/Shi. SD/gShi, and F344/DuCrj rats were given 0.02% NNM in drinking water for 8 weeks and thereafter left without any treatment. The experiment ceased at week 20, because mortality markedly increased after this time point in WS/Shi rats. Liver weight was highest in WS/Shi rats among the three strains examined. The incidence of HCC was 15/15 (100%) in WS/Shi rats, 1/16 (6%) in SD/gShi rats, and 13/16 (81%) in F344/DuCrj rats surviving after NNM treatment. Metastasis to the lung was observed in HCC-bearing rats at an incidence of 13/15 (87%) in WS/Shi, 1/1 in SD/gShi, and 6/13 (46%) in F344/DuCrj. Four-week administration of NNM resulted in a significantly higher BrdU-labeling index of hepatocytes in WS/Shi rats than in the other strains. These findings indicated that WS/Shi is the most sensitive strain to NNM and may be the most suitable strain for use as a spontaneous metastatic model of HCC among the strains of rats examined in the present study.

Effect of liquid paraffin on antibody responses and local adverse reactions of bivalent oil adjuvanted vaccines containing newcastle disease virus and infectious bronchitis virus

Effects of liquid paraffin on antibody responses and local adverse reactions after intramuscular injection of oil adjuvanted vaccines containing Newcastle disease (ND) and infectious bronchitis (IB) virus were investigated in chickens. Each vaccine was prepared with a liquid paraffin such as Carnation, Crystol 52 and Lytol. These vaccines induced sustained antibody responses against ND and IB. Among local adverse reactions, Lytol induced granulomatous reactions and abscesses, but Carnation and Crystol 52 did not. The residual weight of liquid paraffin at the injection site decreased in the order Carnation, Crystol 52, Lytol. Crystol 52 was composed of relatively few short-chain hydrocarbons (i.e., <n-C16H34) and long-chain hydrocarbons (i.e., >n-C20H42). The vaccine with liquid paraffin mainly composed of n-C16H34-n-C20H42 was suggested to induce fewer adverse reactions.

Local Fibrinolysis for Middle Cerebral Artery Embolism Criteria for the Indication by Evaluation of Residual Cerebral Blood Flow and the Results

We summarize our clinical experience of the local fibrinolysis for the middle cerebral artery (MCA) embolism. We added residual CBF factors of the ischemic territories to the usual criteria for the indication of fibrinolysis by Xe-SPECT CBF measurement. Forty-nine cases of local fibrinolysis for MCA embolism were reviewed and the results were compared with the conservative medical treatment cases.

Angiographical improvements were achieved in 38 cases (76%, full reopening 17/49, partial reopening 21/49) and favorable outcomes (good recovery at GOS) were obtained in 32 cases (65%) at three months follow-up outcome. In comparison with the conservative medical treatment, fibrinolysis was superior at good recovery rate, severe disability rate and the resulted large infarction rate with statistical significance.

We concluded that the local fibrinolysis with evaluation of the residual CBF of the ischemic territories achieved good results and outcomes and superior to the conservative medical treatment at some points. To keep the therapeutic time window, it is necessary to include the CBF factor to the criteria for the indication of this treatment.

Immunoreactivity for glutamic acid decarboxylase and N-methyl-D-aspartate receptors of intracellularly labeled respiratory neurons in the cat

In adult cats, immunofluorescence images of glutamic acid decarboxylase (GAD) and N-methyl-D-aspartate (NMDA) receptors were achieved in the ventral respiratory group (VRG) neurons, which had been individually identified by in vivo intracellular recording and labeling with neurobiotin. Among augmenting inspiratory (aug-I), postinspiratory (post-I), and augmenting expiratory (aug-E) neurons labeled, GAD-immunoreactivity was demonstrated only in those neurons that were not antidromically activated (NAA) by stimulation of the vagus nerve and the C2-C3 spinal cord. Substantial immunoreactivity for NMDA receptors was presented in virtually all types of neurons, but lesser reactivity in aug-E bulbospinal neurons. These results suggest that the aug-I, post-I, and aug-E types of NAA neurons are gamma-aminobutyric acid (GABA)ergic and that NMDA receptors distribute in lesser degree in aug-E bulbospinal neurons than in other types of VRG neurons.

Extrahepatic large hepatocellular carcinoma with peritoneal dissemination: multimodal treatment, including four surgical operations

We report a patient with extrahepatically growing large hepatocellular carcinoma (HCC) associated with disseminated intraabdominal tumor and spontaneous tumor bleeding who was treated with four operations, transcatheter arterial embolization, systemic chemotherapy, and hyperthermia. It took 12 months for the multimodal treatment to normalize the alpha-fetoprotein (AFP) level, and remission continued for 6 months. We performed the fourth surgical treatment for a recurrent abdominal tumor involving the small intestine and mesentery, but the patient died 26 months after the first admission. Multimodal treatment, including repeat surgical treatments, for such advanced HCC should be encouraged, to prolong life and to maintain quality of life.

Severe complications of mediastinal pancreatic pseudocyst: report of esophagobronchial fistula and hemothorax

We report two patients with alcoholic pancreatic pseudocyst which communicated to the mediastinal space through the aortic hiatus, in one patient resulting in hypotensive shock due to hemothorax, and in the other, resulting in esophagobronchial fistula via the mediastinal cyst. The first patient was successfully treated by radical resection of the pancreatic body and tail, and the spleen, with an ultrasonic scalpel, although inflammatory changes caused by pancreatitis were so prominent that the splenic vein was occluded. The second patient could not be treated surgically, because the superior mesenteric vein had been occluded by chronic pancreatitis; he died of respiratory failure and sepsis due to aspiration pneumonia, despite receiving medical treatment.

Relationship between antigen release and antibody response of infectious coryza water-in-oil-in-water emulsion vaccines

The relationship between the antigen release from formulations in vitro and the antibody response after administration of water-in-oil-in-water (W/O/W) emulsion vaccines containing Haemophilus paragallinarum (Hpg) was studied in chickens. Increases of sorbitan sesquioleate volume in the formulation led to slower antigen release and tended to induce higher hemagglutination-inhibition (HI) antibody titers. In addition, the vaccines prepared with internal aqueous phase:oil phase:external aqueous phase (A:O:A) ratios of 3:4:3 and 3:3:4 also showed slower release of antigen and higher HI antibody titer compared with those of an A:O:A ratio of 3:2:5. Vaccines prepared with polyoxyethylene (POE)(10) hydrogenated castor oil or POE(40) hydrogenated castor oil instead of sorbitan sesquioleate showed higher release and lower antibody HI titers. As a result, HI antibody titers at 6 wk after vaccination were inversely related to antigen release, as determined by the release test. The correlation coefficient was 0.942. In infectious coryza W/O/W emulsion vaccines, the slow release of antigen from the formulation induced and maintained high HI antibody titers of Hpg.

Aldosterone overproduction and CYP11B2 mRNA overexpression in vessels of spontaneously hypertensive rats

Aldosterone is synthesized in extra-adrenal tissues such as blood vessels and brain. Damage to blood vessels could play a crucial role in perpetuating hypertension. In this study, we determined both aldosterone production and aldosterone synthase gene-CYP11B2 mRNA expression in vessels of spontaneously hypertensive rats (SHR). The results showed that aldosterone was overproduced in the vasculature of SHR, by means of ex vivo mesenteric artery perfusion, HPLC, and RIA, and that CYP11B2 mRNA expression was upregulated in aortas of SHR, confirmed by RT-PCR and Southern blot.

Adjuvanticity and inflammatory response following administration of water-in-oil emulsions prepared with saturated hydrocarbons in chickens

Water-in-oil emulsions containing bovine serum albumin (BSA) as a model antigen were prepared using aliphatic saturated hydrocarbons with carbon number from 12 to 18, and were tested in chickens. Straight-chain hydrocarbons induced higher antibody titers against BSA after administration than branched-chain hydrocarbons. n-C16H34 and n-C18H38 maintained high antibody titers even at 32 weeks after administration, compared with n-C12H26, n-C14H30 and n-C15H32. n-C12H26 and n-C14H30 raised concentrations of sialic acid and creatine kinase in plasma, both of which are important markers of inflammatory responses, immediately after administration. n-C16H34 and n-C18H38 did not raise the values of these markers. These results indicated that n-C16H34 and n-C18H38 induced elevated and sustained immune responses without severe adverse reactions in chickens.

Relation between antigen release and immune response of oil adjuvanted vaccines in chickens

The relationship between release properties of the model antigen, bovine serum albumin (BSA), from formulations in vitro and immune response after administration of various oil adjuvanted vaccines containing liquid paraffin was examined in chickens. The vaccine prepared at an hydrophile-lipophile-balance (HLB) number of 4.8 showed slower release of BSA and higher immune response on injected chickens than that with an HLB number of 6.0. Decreases of aqueous volume ratio in the formulation also led to slower release of BSA and higher immune response. The slower release rate of BSA showed higher ELISA antibody titer even at 20 weeks after vaccination. The ELISA antibody titer inversely was related to the constant release rate, k, calculated from the in vitro release test. The correlation coefficient was 0.863. The immune response of oil adjuvanted vaccines containing Haemophilus paragallinarum agreed well with these results with BSA. Our results indicated that a stronger and more prolonged immune response of oil adjuvanted vaccines was achieved by slower release rate of antigen from the formulation. In addition, there was a good correlation between immune response and the value of k.

Neuropharmacology of control of respiratory rhythm and pattern in mature mammals

This review summarizes the current understanding of the neurotransmitters and neuromodulators that are involved, firstly, in respiratory rhythm and pattern generation, where glutamate plays an essential role in the excitatory mechanisms and glycine and gamma-aminobutyric acid mediate inhibitory postsynaptic effects, and secondly, in the transmission of input signals from the central and peripheral chemoreceptors and of motor outputs to respiratory motor neurons. Finally, neuronal mechanisms underlying respiratory modulations caused by respiratory depressants and excitants, such as general anesthetics, benzodiazepines, opioids, and cholinergic agents, are described.

11beta-hydroxysteroid dehydrogenase in human vascular cells

Aldosterone selectivity in mineralocorticoid target tissues is mainly due to 11beta-hydroxysteroid dehydrogenase (11betaHSD), which converts cortisol to its inactive metabolite cortisone in humans. The defect of dehydrogenase activity would thus allow type 1 mineralocorticoid receptor (MR) to be occupied mostly by cortisol. It has been postulated that 11betaHSD type 2 (11betaHSD2) plays a significant role in conferring ligand specificity on the MR. We have demonstrated the diminished dehydrogenase activity in resistance vessels of genetically hypertensive rats. However, the mechanism that could link impaired vascular 11betaHSD activity and elevated blood pressure has been unclear. In this study, we showed the enzyme activity in human coronary artery smooth muscle cells. Glucocorticoids and mineralocorticoids increase vascular tone by up-regulating the receptors of pressor hormones such as angiotensin II (Ang II). Next, we found that physiological concentrations of a cortisol-induced increase in Ang II binding were significantly enhanced by the inhibition of dehydrogenase activity with an antisense DNA complementary to 11betaHSD2 mRNA, and the enhancement was partially but significantly abolished by a selective aldosterone receptor antagonist. This may indicate that impaired dehydrogenase activity in vascular wall results in increased vascular tone by the contribution of cortisol, which acts as a mineralocorticoid. In congenital 11betaHSD deficiency and after the administration of 11betaHSD inhibitors, suppression of dehydrogenase activity in the kidney has been believed to cause renal mineralocorticoid excess, resulting in sodium retention and hypertension. These results show that vascular 11betaHSD activity could influence blood pressure without invoking renal sodium retention.

Contribution of NMDA receptors to activity of augmenting expiratory neurons in vagotomized cats

To identify the NMDA receptor-mediated mechanism in augmenting expiratory (E2) neurons, the effects of systemic and local application of dizocilpine on spontaneous and evoked postsynaptic potentials (PSPs) were investigated in decerebrate and vagotomized cats. Intravenously applied dizocilpine reduced the inhibitory PSPs during inspiration and stage 1 expiration, but had little effect on the excitatory PSPs during stage 2 expiration. Iontophoresed dizocilpine caused a continuous hyperpolarization throughout the respiratory cycle. Dizocilpine had no effect on vagally evoked PSPs. These results suggest that the NMDA mechanisms are involved presynaptically in periodic postsynaptic inhibitions and postsynaptically in tonic excitation in E2 neurons.

Synaptic interactions between respiratory neurons during inspiratory on-switching evoked by vagal stimulation in decerebrate cats

To elucidate neuronal mechanisms underlying phase-switching from expiration to inspiration, or inspiratory on-switching (IonS), postsynaptic potentials (PSPs) of bulbar respiratory neurons together with phrenic nerve discharges were recorded during IonS evoked by vagal stimulation in decerebrate and vagotomized cats. A single shock stimulation of the vagus nerve applied at late-expiration developed an inspiratory discharge in the phrenic neurogram after a latency of 79+/-11 ms (n = 11). Preceding this evoked inspiratory discharge, a triphasic response was induced, consisting of an early silence (phase 1 silence), a transient burst discharge (phase 2 discharge) and a late pause (phase 3 pause). During phase 1 silence, IPSPs occurred in augmenting inspiratory (aug-I) and expiratory (E2) neurons, and EPSPs in postinspiratory (PI) neurons. During phase 2 discharge, EPSPs arose in aug-I neurons and IPSPs in PI and E2 neurons. These initial biphasic PSPs were comparable with those during inspiratory off-switching evoked by the same stimulation applied at late-inspiration. In both on- and off-switching, phase-transition in respiratory neuronal activities started to arise concomitantly with the phrenic phase 3 pause. These results suggest that vagal inputs initially produce a non-specific, biphasic response in bulbar respiratory neurons, which consecutively activates a more specific process connected to IonS.

alphaPIX nucleotide exchange factor is activated by interaction with phosphatidylinositol 3-kinase

p21-activated kinase (PAK) is a common effector protein of the small GTPases Cdc42 and Rac, leading to the activation of downstream mitogen activated protein kinases. PAK also mediates polarized cytoskeletal changes induced by these GTPases. The recently identified PAK-interacting exchange factor (PIX) acts as a guanine nucleotide exchange factor on Rac, and colocalizes with PAK in a focal complex, but little is known about the associated signaling cascades, including upstream activators of PIX. In this study, we show that one of the isoforms of PIX, alphaPIX, is activated by signaling cascades from the platelet-derived growth factor (PDGF) receptor and EphB2 receptor, and from integrin-induced signaling through phosphatidylinositol 3-kinase (PI3-kinase). alphaPIX is activated by forming a complex with these receptors either via association with PAK and Nck, or direct association with the p85 regulatory subunit of PI3-kinase. Synthetic phosphoinositide and membrane targeted PI3-kinase augmented the alphaPIX activity in vivo. In Xenopus, aggregates of mesodermal cells derived from embryos microinjected with alphaPIX significantly increased the peripheral spreading on fibronectin substrate in response to PDGF through PI3-kinase. These results indicate that alphaPIX is activated by PI3-kinase, and is involved in the receptor mediated signaling leading to the activation of the kinase activity of PAK, and the migration of mesodermal cells on extracellular matrix.

GABA(A) receptor-mediated inspiratory termination evoked by vagal stimulation in decerebrate cats

To identify the GABAergic inhibitory mechanisms involved in inspiratory termination or off-switching (IOS), the effects of a specific enhancer of GABA(A) receptors, midazolam, and an antagonist, bicuculline, on vagally evoked inspiratory inhibitions and IOS were investigated in decerebrate cats. Stimulation of vagal afferents at late inspiration provoked either reversible inspiratory inhibition or IOS, depending on the stimulus intensity. Each response occurred at a constant latency (phase 1). The reversible response was triphasic, consisting of an early (phase 2) inhibition, a brief (phase 3) excitation and a late (phase 4) inhibition in the phrenic neurogram, and early (phase 2) IPSPs, brief (phase 3) EPSPs and late (phase 4) IPSPs in bulbar inspiratory (I) neurones. With an increasing stimulus intensity, phase 4 inhibitions were increased in amplitude and duration, leading to IOS. Midazolam (0.1 mg/kg i.v.) increased more selectively phase 4 IPSPs than phase 2 IPSPs in I neurones, and decreased the threshold for evoking IOS by producing an earlier and larger phase 4 IPSPs. Bicuculline (1.0 mg/kg i.v.) had an opposite effect. These results suggest that the late inhibitory response evoked by vagal stimulation in the I neuronal pool organizes an initial phase of IOS which is mediated by GABA(A) receptors.

Related changes in sympathetic activity, cerebral blood flow and intracranial pressure, and effect of an alpha-blocker in experimental subarachnoid haemorrhage

We investigated the changes in sympathetic nerve activity (SNA) and cerebral blood flow (CBF) with or without increase in intracranial pressure (ICP) in the acute stage of experimental subarachnoid haemorrhage (SAH). ICP was increased or controlled by rapid or slow injection of blood and saline, and the effect of an alpha-blocker, phentolamine, was also investigated in each condition. Following marked increase in ICP induced by rapid injection of blood or saline, increase in intracranial and general SNA and decrease in CBF were observed. Both changes were significantly decreased in magnitude by prior administration of phentolamine. When increase in ICP was not induced, by slow injection of blood, both SNA and CBF decreased, and these changes were alleviated by phentolamine. However, when increase in ICP was not induced by saline, neither SNA nor CBF significantly changed. These findings suggest that marked increase in ICP is the primary cause of the pathological changes occurring immediately after SAH, and that the decrease in CBF in mild SAH without increase in ICP is caused by blood itself. Administration of an alpha-blocker may be effective in improving the abnormal sympathetic nervous system induced by marked increase in ICP.

NMDA receptor-mediated inspiratory off-switching in pneumotaxic-disconnected cats

The pneumotaxic center is thought to govern inspiratory off-switching (IOS), and blockade of N-methyl-D-aspartate (NMDA) receptors by dizocilpine impairs IOS causing apneusis. The present study is to examine whether the NMDA receptor-mediated IOS mechanism functions in the medullary respiratory network after disconnecting the pneumotaxic center. In decerebrate and vagotomized cats, the nucleus parabrachialis medialis (NPBM) and vagus nerves were stimulated to evoke IOS and a dorsal pontine transection was performed while the central respiratory activity was recorded in phrenic neurogram. The transection eliminated the NPBM-stimulated IOS but not the vagally evoked IOS, and developed two types of respiration; eupnea in 12 and apneusis in six out of 18 cats. Apneustic respiration was not changed into eupneic one by changing the end-tidal CO2 level. In animals displaying eupnea after the transection, dizocilpine (0.3 mg/kg i.v.) produced apneusis, characterized by a prolonged inspiration, a shortened stage 1 expiration and an unchanged stage 2 expiration. Dizocilpine caused no further change in the apneustic pattern induced by the transection. The present results suggest that the medullary respiratory network is able to generate a eupneic respiration after disconnecting the pontine pneumotaxic center, and the NMDA mechanism plays an important role in the medullary respiratory network.