Abstract P4-08-24: Prognostic significance of preoperative neutrophil-to-lymphocyte ratio in postmenopausal breast cancer patients

Background: Several studies have shown the association between high neutrophil-to-lymphocyte ratio (NLR) and poor prognosis in various cancer types, including breast cancer. On the other hand, menopausal status, which is an important consideration in breast cancer treatment, has been shown to be associated with changes in NLR levels. The purpose of the present study was to clarify the prognostic significance of preoperative NLR, especially in postmenopausal breast cancer patients.

Patients and methods: Between October 2003 and December 2014, 1868 women underwent surgery without neoadjuvant systemic therapy for primary breast cancer in our department. The optimal cutoff value of preoperative NLR was determined using receiver operating characteristic curve analysis. The patients were divided into two groups based on the NLR cutoff value of 3.34: High NLR (NLR value ≥ 3.34) and Low NLR (NLR value < 3.34). Correlations between clinicopathological characteristics and preoperative NLR were analyzed, and relapse-free survival (RFS) and overall survival (OS) were estimated.

Results: Among the 1868 patients, 286 (15.3%) and 1582 (84.7%) patients were classified into High NLR and Low NLR, respectively. Although the patients in High NLR was younger (p=0.0023), there were no significant correlations between NLR and all other prognostic factors, such as tumor size, lymph node status, and histological grade. High NLR was associated with tendency to shorter RFS (p=0.0583) and shorter OS (p=0.0303). In postmenopausal patients (n=1177), significant correlations were observed between High NLR and shorter RFS and OS (p=0.0002 and p=0.0011). However, NLR was not correlated with RFS and OS in premenopausal patients (n=691). Although the postmenopausal patients with relapsed cancer had higher NLR levels than those without relapse (p=0.0252), NLR levels were not correlated with relapse occurrence in premenopausal patients. Both univariate (p=0.0009) and multivariate (p=0.0015) analyses revealed that High NLR as well as larger tumor size, lymph node metastases, and higher histological grade was significantly associated with relapse in postmenopausal patients. Moreover, in postmenopausal patients, subgroup analysis according to cancer subtype revealed that High NLR was correlated with shorter RFS only in patients with hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer (p=0.0009), in those without adjuvant chemotherapy (p=0.0034) but not in those with adjuvant chemotherapy.

Conclusion: Elevated preoperative NLR is an independent predictor of poor prognosis in postmenopausal but not premenopausal patients with breast cancer. In postmenopausal patients, adjuvant chemotherapy may improve prognosis in patients with HR-positive/HER2-negative breast cancer, especially in those with elevated preoperative NLR.

Citation Format: Ijichi H, Tajiri W, Masuda T, Koga C, Tanaka J, Nakamura Y, Okamoto M, Tokunaga E. Prognostic significance of preoperative neutrophil-to-lymphocyte ratio in postmenopausal breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-24.

Abstract P2-09-33: Not presented

This abstract was not presented at the symposium.

Left lobe living donor liver transplantation in adults

Adult left lobe (LL) living donor liver transplantation (LDLT) has not generally been recognized as a feasible procedure because of the problem of graft size. The objectives of this study were to assess the feasibility and short- and long-term results of adult LL LDLT in comparison with right lobe (RL) LDLT. Data on 200 consecutive LL LDLTs, including five retransplants, were retrospectively compared with those of 112 RL LDLTs, in terms of survival, complications and donor morbidity. The mean graft weight to standard volume ratio of LL grafts was 38.7% whereas that of RL grafts was 47.6% (p < 0.0001). The 1-, 5- and 10-year patient survival rates of LL LDLT were 85.6%, 77.9% and 69.5%, respectively, which were comparable to those of RL LDLT (89.8%, 71.3% and 70.7%, respectively). The incidence of small-for-size syndrome was higher in LL LDLT (19.5%) than in RL LDLT (7.1%) (p < 0.01). The overall donor morbidity rates were comparable between LL (36.0%) and RL (34.8%), whereas postoperative liver function tests and hospital stay were significantly better (p < 0.0001) in LL donors. In conclusion, adult LL LDLT has comparable outcomes to that of RL LDLT. LL LDLT is viable and is the first choice in adult LDLT.

Deceleration of regenerative response improves the outcome of rat with massive hepatectomy

Small residual liver volume after massive hepatectomy or partial liver transplantation is a major cause of subsequent liver dysfunction. We hypothesize that the abrupt regenerative response of small remnant liver is responsible for subsequent deleterious outcome. To slow down the regenerative speed, NS-398 (ERK1/2 inhibitor) or PD98059 (selective MEK inhibitor) was administered after 70% or 90% partial hepatectomy (PH). The effects of regenerative speed on liver morphology, portal pressure and survival were assessed. In the 70% PH model, NS-398 treatment suppressed the abrupt replicative response of hepatocytes during the early phase of regeneration, although liver volume on day 7 was not significantly different from that of the control group. Immunohistochemical analysis for CD31 (for sinusoids) and AGp110 (for bile canaliculi) revealed that lobular architectural disturbance was alleviated by NS-398 treatment. In the 90% PH model, administration of NS-398 or PD98059, but not hepatocyte growth factor, significantly enhanced survival. The abrupt regenerative response of small remnant liver is suggested to be responsible for intensive lobular derangement and subsequent liver dysfunction. The suppression of MEK/ERK signaling pathway during the early phase after hepatectomy makes the regenerative response linear, and improves the prognosis for animals bearing a small remnant liver.

Estimation of standard liver volume for Japanese adults

INTRODUCTION

Accurate pretransplant estimation of the recipient's standard liver volume (SLV) is important. The purpose of this study was to compare reported formulas for clinical estimation of liver volume among Japanese adults.

METHODS

We reviewed data on 70 healthy adults (46 men, 24 women, ages 20 to 65 years old) evaluated for living donor liver transplantation. Liver volume (LV) was measured using two- or three-dimensional computed tomography volumetry (CTV). The formulas of DeLand (LV = 1020 x body surface area [BSA] - 220), Urata (LV = 706.2 x BSA + 2.4), Noda (LV = 50.12 x BW(0.78)), Heinemann (LV = 1072.8 x BSA - 345.7), Vauthey (LV = 18.51 x BW + 191.8) and Yoshizumi (LV = 772 x BSA) were applied to estimate LV. We calculated the differences for individual donors betwen CTV and LV estimated by each formula.

RESULTS

Mean LVs as estimated by the formulae of DeLand and Heinemann et al were significantly greater (P < .01) than the mean CTV, while LV estimated by the formula of Urata was significantly less (P < .05) than the CTV. The formulas of DeLand and Heinemann overestimated LV, while the formula of Urata underestimated it. The formulae of Noda et al and Yoshizumi et al tended to underestimate the LV when the CTV was greater than 1600 cm(3). When the Yoshizumi formula was applied, the number of donors with an acceptable difference (+/-15%) between CTV and estimated LV was 55 (78.6%).

CONCLUSIONS

The Yoshizumi formula was applicable, especially for patients with a BSA < 2.0, whereas the well-known Urata formula made LV underestimates.

Feasibility of left lobe living donor liver transplantation between adults: an 8-year, single-center experience of 107 cases

Operative mortality for a right lobe (RL) donor in adult living donor liver transplantation (LDLT) is estimated to be as high as 0.5-1%. To minimize the risk to the donor, left lobe (LL)-LDLT might be an ideal option in adult LDLT. The aim of the study was to assess the feasibility of LL-LDLT between adults based on a single-center experience of 107 LL-LDLTs performed over 8 years. The mean graft weight of LL grafts was 452 g, which amounted to 40.5% of the estimated standard liver volume of the recipients. The overall 1-, 3- and 5-year patient survival rates in LL-LDLT were 81.4, 76.9 and 74.7%, respectively, which were comparable to those of RL-LDLT. Twenty-six grafts (24.3%) were lost for various reasons with three losses directly attributable to small-for-size graft syndrome. Post-operative liver function and hospital stay in LL donors were significantly better and shorter than that in RL donors, while the incidence of donor morbidity was comparable between LL and RL donors. In conclusion, LL-LDLT was found to be a feasible option in adult-to-adult LDLT. Further utilization of LL grafts should be undertaken to keep the chance of donor morbidity and mortality minimal.

The hepatitis B virus X protein enhances AP-1 activation through interaction with Jab1

Hepatitis B virus X protein (HBx) has many cellular functions and is a major factor in hepatitis and hepatocellular carcinoma caused by HBV infection. A proteomic approach was used to search for HBx-interacting proteins in order to elucidate the molecular mechanism of hepatocarcinogenesis. HBx was attached to myc and flag tags (MEF tags) and expressed in 293T cells; the protein complex formed within the cells was purified and characterized by mass spectrometry. COP9 signalosome (CSN) subunits 3 and 4 were subsequently identified as HBx-interacting proteins. In addition, CSN subunit 5, Jun activation domain-binding protein 1 (Jab1), was shown to be a novel cellular target of HBx. In vivo and in vitro interactions between HBx and Jab1 were confirmed by standard immunoprecipitation and GST pull-down assays. An analysis of HBx deletion constructs showed that amino acids 30-125 of HBx were responsible for binding to Jab1. Confocal laser microscopy demonstrated that HBx was mainly localized in the cytoplasm, while Jab1 was found mainly in the nucleus and partially in the cytoplasm, and that the two proteins colocalized in the cytoplasm. The cotransfection of HBx and Jab1 resulted in substantial activator protein 1 (AP-1) activation and knockdown of endogenous Jab1 attenuated AP-1 activation caused by HBx. In addition, the coexpression of HBx and Jab1 potentiated phosphorylation of JNK, leading to the subsequent phosphorylation of c-Jun, whereas the level of c-Jun and JNK phosphorylation induced by HBx was decreased in Jab1 knockdown cells. These results suggest that the interaction between HBx and Jab1 enhances HBx-mediated AP-1 activation.

Living donor liver transplantation for hepatocellular carcinoma: a special reference to a preoperative des-gamma-carboxy prothrombin value

BACKGROUND

Des-gamma-carboxy prothrombin (DCP) is a sensitive marker related to vascular invasion of hepatocellular carcinoma (HCC). The aim of this study was to clarify the risk factors of HCC recurrence in living donor liver transplantation (LDLT) with special reference to preoperative DCP values.

METHODS

Forty consecutive adult HCC patients who underwent LDLT were examined for a correlation between the DCP value and vascular invasion. Risk factors for recurrence were also investigated using clinicopathological variables including preoperative DCP levels.

RESULTS

The incidence of positive histological vascular invasion in patients with DCP values above 300 mAU/mL was higher than that with those with DCP value below 300 mAU/mL. Other significant risk factors for recurrence were over 5 cm tumor diameter, not meeting the Milan criteria, AFP value >400 ng/mL, histological vascular invasion, poorly differentiated histology, and male gender. Among the patients who did not meet the Milan criteria, those with both no more than 5 cm of tumor diameter and no more than 300 mAU/mL DCP exhibited a good prognosis.

CONCLUSIONS

A high DCP value, namely >300 mAU/mL correlated with histological vascular invasion and was one of the strongest prognostic variables. Therefore, special attention should be paid to HCC patients with high DCP values. No correlation between the number of tumor nodules and recurrence was found; therefore, the Milan criteria may require revision regarding the number of tumor nodules.

Is graft size a major risk factor in living-donor adult liver transplantation?

Graft size is known to be a major risk factor in living donor adult liver transplantation (LDALT). The aim of this study is to reassess whether graft size is a critical factor in LDALT or not. A series of 75 LDALTs excluding auxiliary transplantation and ABO blood-type incompatible transplantation were analyzed. The patients were divided into two groups, according to graft volume (GV) and standard liver volume (SLV): group 1 (small-size group) (GV/SLV: <40%), and group 2 (non-small-size group) (> or =40%). Perioperative clinical data were compared between the two groups, including graft survival and postoperative complications. These parameters were also compared under the conditions of cirrhotic recipients. No difference in graft survival was found between the two groups. No difference was found in incidence of postoperative complications, such as intractable ascites and persistent hyperbilirubinemia. Even in cirrhotic patients with Child-Pugh's class C, there was no difference in graft survival between the two groups. Risk factors related to graft loss were a preoperative urgent status due to chronic liver disease, pre-operative hyperbilirubinemia of over 10 mg/dl, and ABO blood type of not identical but compatible combination between donor and recipient. Graft size is not always considered to be a major risk factor in LDALT, although the number of patients was small in this study. Therefore, a left-lobe graft, even a "small-for-size" graft for adult recipients, remains a feasible option in LDALT.

False positive uptake of metaiodobenzylguanidine in hepatocellular carcinoma

We present the case of a patient who showed increased accumulation of (123)I-metaiodobenzylguanidine (MIBG) in hepatocellular carcinoma, leading to a false presumptive diagnosis of intrahepatic neuroendocrine tumour. The increase in uptake was not seen on images obtained 4 h after tracer injection but was evident on those taken after 24 h, suggesting slower washout from the liver tumour than from non-tumoural liver parenchyma. Our observations indicate that a non-neuroendocrine malignant tumour may exhibit high accumulation of MIBG associated with prolonged retention.

Systematic analysis of the TGF-beta-Smad signaling pathway in gastrointestinal cancer cells

The transforming growth factor-beta (TGF-beta)-Smad signaling pathway has an important role in carcinogenesis. To study the frequency and mechanism of functional impairment of this pathway in human gastrointestinal cancers, we used a reporter assay to examine the response of 38 cell lines (11 colorectal, 9 pancreatic, 10 gastric, and 8 hepatic cancers) to TGF-beta. We then analyzed TGF-beta type II receptor (T beta RII) gene, immunoblots of Smad4, and restoration of the pathway by rescuing T beta R or Smad. We observed impaired signaling in 91% of colorectal, 67% of pancreatic, and 40% of gastric cancer cell lines, but in none of the hepatic cancer cells. We suggest that this pathway does not function as a tumor suppressor in hepatic carcinogenesis. The impairment is due to inactivation of T beta RII and Smad4 in colorectal and pancreatic cancers. However, because the signal was not recovered by rescuing T beta R or Smad genes in TGF-beta-response-defective gastric cancer cell lines, we suggest that novel molecules or mechanisms are involved in the impaired pathway in some gastric cancers.

Frameshift mutations at mononucleotide repeats in RAD50 recombinational DNA repair gene in colorectal cancers with microsatellite instability

To identify additional genes targeted for microsatellite instability (MSI), we search for human genes which contain mononucleotide repeats in their coding region, selected 7 genes (RAD50, DNA-PKcs, FLASH, Apaf-1, XPG, CtIP, and MLSN1), and analyzed frameshift mutations in them. Here we report that 60% (3 out of 5) of human colorectal cancer cell lines exhibiting a high frequency of MSI (MSI-H) and 46% (6 out of 13) of MSI-H primary colorectal tumors had mutations in the (A)9 repeat of RAD50 recombinational repair gene. In contrast, no frameshift mutations were found in any of the 5 MSI-negative colorectal cancer cell lines, 8 colorectal tumors exhibiting a low frequency of MSI (MSI-L), or 28 MSI-negative colorectal tumors. No mutations were found in the mononucleotide repeats of 6 other genes, even in MSI-H cancers. These results suggest that RAD50 frameshift mutations may play a role in the tumorigenesis of MSI-H colorectal cancers.

Molecular cloning and characterization of a human homologue of TBPIP, a BRCA1 locus-related gene

Here we clone the human homologue of TBPIP [Tat binding protein 1(TBP-1)-interacting protein]. TBPIP is a molecule that has been cloned from mouse as a cofactor of TBP-1. Eighty-eight per cent of the deduced amino acid sequence of human TBPIP coincides with that of mouse TBPIP. CAT assay reveals that human TBPIP could interact with human TBP-1, then enhance the function of TBP-1 on HIV (human immunodeficiency virus)-Tat-mediated transactivation. Our radiation hybrid mapping indicates that TBPIP is located on chromosome 17q12-21. A DNA database search uncovers that an apparent part of TBPIP has been obtained as a BRCA1 locus-related gene (OV-4) and mapped onto chromosome 17q12-21. Interestingly, the nucleotide structure of human TBPIP is very similar to that of the GT198 gene, which has been cloned from a human breast cancer cell line and also mapped onto the BRCA1 locus. Since a very high rate of gene mutation is observed in the BRCA1-related region in breast cancers and expression of authentic GT198 mRNA could not be confirmed in either BT-474 (other kind of human breast cancer cell line) or normal human testis (where the strong expression of GT198 mRNA is reported), it is likely that GT198 is a mutated form of human TBPIP.

[Report of two cases with idiopathic true exfoliation of the lens capsule--histopathological and electron microscopical study]

True exfoliation is a delamination of the superficial or all layers of the anterior lens capsule, appearing as a transparent membrane in the anterior chamber. It is a rare occurrence and most of the reported cases have been associated with histories of exposure to excessive heat, ocular trauma, or intraocular inflammation. We report two cases of idiopathic true exfoliation without any contributory history. In one case, the lens was surgically removed intracapsularly, and served for histological study and scanning and transmission electron microscopy. The anterior fourth of the capsule was delaminated. Underlying epithelial cells showed nonspecific senile changes.

[Scanning and transmission electron microscopic studies of the ultrastructure of the corneal endothelium in developing human eye]

The ultra-microstructure of the human corneal endothelium was examined by scanning and transmission electron microscopy. The samples were corneas of 26 human eyes taken from fetuses of 5-22 weeks gestation and a newborn 10 months after birth. Corneal endothelium appeared at the seventh or eighth week after gestation. Initially, they formed an irregular structure of two to three layers. From the 17th week of gestation they formed a single layer, and assumed the form of a cuboidal epithelium. Scanning and transmission electron microscopy showed numerous microvilli protruding towards the anterior chamber. Within the microvilli uniform microtubules were observed. By the 20th week, these microvilli disappeared, and subsequently, a single long narrow cilium appeared in the center of each cell. Each cilium had an axial filament complex structure. This cilium involuted as development progressed, and was barely visible by the 10th month after birth. The significance of this cilium is not clear.

[A juvenile case of mesenchymal chondrosarcoma originating from soft tissue in the orbit]

Mesenchymal chondrosarcoma is a very rare occurrence in the orbit. A 10-year-old girl presented with right exophthalmos. Computed tomography revealed a round tumor inside the muscular cone of the right orbit. There was a sign of slight calcification inside the tumor. The tumor was surgically removed by the Krönlein-Berke procedure. Histopathological examination showed undifferentiated mesenchymal cells and cartilage tissue. A recurrent tumor was found in the same location 34 months after the surgery, which was removed by frontal approach saving the globe with normal function. Histopathology of the recurrent tumor revealed a slight difference from the primary tumor, showing hemangiopericytoma pattern without cartilage components. Immunohistochemical studies of the primary and recurrent tumors showed their cells to be positive for antifactor VIII and S-100, and negative for myoglobin and monoclonal antibody to muscle actin. Electron microscopically these undifferentiated cells had large nucleus and very scanty cytoplasm, mostly containing glycogen granules. This is probably the first description of a juvenile case of mesenchymal chondrosarcoma originating from soft tissue in the orbit.

A double-blind comparative study of doxazosin and prazosin in the treatment of essential hypertension

Two hundred sixty-six patients took part in a multicenter comparative study of doxazosin and prazosin. Both drugs produced a significant reduction (p less than 0.001) in blood pressure and no increase in heart rate. Blood pressure was considered "markedly decreased" or "decreased" in 70.8% of patients treated with doxazosin and 70.0% of patients treated with prazosin. No statistically significant between-group differences in antihypertensive efficacy were observed. Both doxazosin and prazosin were well tolerated; seven patients (5.6%) in each group had the therapy withdrawn.

Central attenuation of aortic baroreceptor reflex in prehypertensive DOCA-salt-loaded rats

To determine whether the arterial baroreceptor reflex can act to oppose the development of hypertension, deoxycorticosterone acetate (DOCA)-salt hypertension was produced in sinoaortic-denervated and sham-operated rats. Systolic blood pressure measured by tail cuff started to increase in both sinoaortic-denervated and sham-operated rats 7 days after DOCA treatment, and the hypertension developed identically in both denervated and sham-operated rats. These findings suggest that the baroreceptor reflex cannot act against the development of hypertension. To determine whether the baroreceptor reflex is attenuated before the development of hypertension, bradycardiac and sympathoinhibitory responses to i.v. injections of norepinephrine were examined. Bradycardic and sympathoinhibitory responses were significantly smaller in DOCA-salt-treated rats in both prehypertensive (5th day after DOCA-salt treatment) and hypertensive stages (21st day after treatment). In urethane-anesthetized DOCA-loaded and control rats on the 5th day after treatment, aortic depressor nerve stimulation elicited frequency-dependent depressor and bradycardic responses accompanied by inhibition of sympathetic nerve activity in both DOCA-loaded and control rats. However, those responses were significantly smaller in DOCA-loaded rats than in control rats. These results suggest that the central component of the baroreceptor reflex mediated by the aortic depressor nerve is impaired before hypertension develops and that this impairment may contribute to the development of hypertension in DOCA-salt-treated rats.

[Transmitral blood flow velocity patterns evaluated by pulsed Doppler echocardiography in diagnosing transient myocardial ischemia]

To evaluate the influences of transient myocardial ischemia on transmitral blood flow velocity patterns, pulsed Doppler echocardiography was performed during coronary artery occlusion in 10 anesthetized open-chest dogs, and also during esophageal pacing or the administration of dipyridamole in 79 patients with coronary artery disease (CAD), and in 19 control subjects. During occlusion of the coronary artery, an abrupt decrease in the peak velocity of the rapid filling wave (R) was noted within one min simultaneously with rapid decrease of % wall thickening in the ischemic regions. The peak velocity of atrial filling was augmented compensatorily. Although the transmitral blood flow velocity pattern did not change in the controls with esophageal pacing, changes similar to those which were obtained during experimental studies were demonstrated in CAD patients. There were no significant differences between transmitral blood flow velocity patterns of patients with multivessel disease and those with single vessel disease. Ischemic changes in transmitral blood flow velocity patterns were not demonstrated in patients with mitral regurgitation. Sublingual nitroglycerin normalized post-pacing abnormal blood flow velocity patterns. In contrast, after the intravenous administration of 0.56 mg/kg of dipyridamole, R and A were increased and the A/R ratio was unchanged both in CAD patients and the control groups. Deceleration time, or the half time, was prolonged during both provocation tests in CAD patients, and these changes were transient and were restored within several min. Furthermore, they were noted more frequently than was the development of ST depression on ECG, or chest pain. These findings indicate that the transmitral blood flow velocity patterns obtained by pulsed Doppler echocardiography are useful for detecting transient myocardial ischemia, though they have limitations in diagnosing the extent of coronary artery disease.

Devices external pulse generator: a reliable temporary pacemaker?

Two cases of malfunctioning APC (American Pacemaker Company) Devices pacemakers are reported. Two patients with sick sinus syndrome were temporarily paced using APC Devices pacemaker models EC 4542 and EV 4543 respectively, which showed transient increase (53% and 83% of the preset rate, respectively) in pacing rate. The sudden increase of the pacing rate might be the pacemaker's design to switch to fixed-rate pacing at nominally 25% higher than the selected rate in the presence of an excessive level of electrical interference. However, the increased rate was much faster than the interference rate. Great caution should be paid when APC Devices pacemaker is to be used.

[Evaluation of right ventricular function in severe left ventricular failure: comparison of old myocardial infarction with dilated cardiomyopathy]

To evaluate right ventricular (RV) function in severe left ventricular (LV) failure, we measured RV and LV ejection fractions (EF) in 18 patients with old myocardial infarction (OMI) and in 18 with dilated cardiomyopathy (DCM) using cardiac blood pool scintigraphy. In patients with OMI, RVEF was significantly greater in stage II LV failure than in stage III (functional class of the New York Heart Association, 47 +/- 8% and 28 +/- 12%, respectively: p less than 0.01), and this correlated well with exercise tolerance by bicycle ergometer and mean pulmonary artery pressure (r = 0.83 and r = -0.71, respectively). In patients with DCM, however, there was no correlation between RVEF and these indexes. After the oral administration of denopamine (beta 1 effector), both RVEF and LVEF increased in patients with OMI (35 +/- 13% to 45 +/- 12%, and 27 +/- 9% to 30 +/- 10%: p less than 0.01), but they did not change significantly in patients with DCM. These results indicate that RVEF in patients with OMI correlates well with subjective symptoms, exercise tolerance and RV afterload, but these correlations were not apparent in patients with DCM. We concluded that RV function in cases of severe LV failure has a different meaning between OMI and DCM.

Evidence for a digitalis-like substance in the hypothalamopituitary axis in rats: implications in the central cardiovascular regulation associated with an excess intake of sodium

The origin and the physiological role of an endogenous digitalis-like substance were investigated by measuring both the digoxin-like substance by a digoxin radioimmunoassay (RIA) and the inhibitory activity on the ouabain sensitive Na+,K+-ATPase in rats. The digitalis-like substance was in high concentration in the pituitary, and in decreasing concentration in the hypothalamus, adrenal and the other organs as measured by RIA using an antibody raised from a goat. However, the adrenal showed the highest content of digitalis-like substance as measured by the antibody raised from a rabbit. The plasma level markedly decreased during a 2-week sodium-loading, and the adrenal content decreased markedly on hypophysectomy as measured with the rabbit-antibody. Therefore, the substance measured with the rabbit-antibody must be one of ACTH-dependent adrenal steroids. The inhibitory activity on the Na+,K+-ATPase was high in the pituitary gland, and was decreased in order of the adrenal, hypothalamus and other organs. The 2-week sodium-loading increased both the content in the pituitary gland and the output in the urine, and decreased the hypothalamic content. Immunohistochemical staining of the hypothalamus with the antibody revealed that the immunoreactivity is restricted to the neurons of the paraventricular nucleus, supraoptic nucleus, magnocellular accessory nuclei and extended their fibers reaching to the inner layer of the median eminence. To determine the role of the substance in the brain, the crude extract dissolved in artificial cerebrospinal fluid was injected into the lateral ventricle; vasopressor responses, tachycardia and hyperactivity of the splanchnic nerve lasting for more than 30 min were recorded, which resembled the responses to ouabain injected similarly.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathophysiological role of dopamine on the development of hypertension in rats

The aim of the study is to investigate the pathophysiological role of dopamine (DA) in the development of hypertension in DOCA-salt hypertensive rats and spontaneously hypertensive rats (SHRs). The augmentation of dopaminergic activity by chronic administration of bromocriptine, a DA agonist, suppressed the increase of blood pressure in DOCA-salt hypertensive rats. In contrast, suppression of dopaminergic activity by chronic administration of carbidopa, an inhibitor of dopa decarboxylase, accelerated the development of hypertension in SHRs, and this acceleration was also increased by salt loading. Increased urinary excretion of norepinephrine (NE) by DOCA-salt treatment was suppressed by the treatment of bromocriptine. In contrast, administration of carbidopa and salt loading in SHRs resulted in an increase in renal NE content and in urinary NE and epinephrine (E) excretion and a decrease in urinary sodium excretion. These results suggest that dopaminergic activity participate in the development of hypertension and decreased dopaminergic activity accelerates the development of hypertension in hypertensive rats mainly through the enhancement of peripheral sympathetic nerve activity.

[Right ventricular systolic and diastolic functions assessed by 81mKr scintigraphy and relation to ventricular septal ischemia]

Right ventricular (RV) systolic and diastolic functions were assessed in patients with previous anteroseptal myocardial infarction to ascertain the influence of interventricular septal ischemia on RV function. Gated right ventriculography with continuous infusion of krypton-81 m was performed in 12 normal subjects and 28 patients with infarction but without significant stenosis of the right coronary artery. Furthermore, RV contractile reserve by postextrasystolic potentiation was evaluated by gated radionuclide ventriculography with 99mTc-HSA. The patients with anteroseptal infarction were divided into two groups by the presence or absence of three hours' redistribution in the septal region on exercise thallium-201 myocardial scintigraphy. Two indices of systolic function (ejection fraction and the peak ejection rate) and three indices of diastolic function (1/3 diastolic filling rate, the peak filling rate and time to the peak filling rate) were derived from the right ventricular time-activity curve and its derivative curve. There was no difference in systolic function among normal subjects and patients with or without redistribution. However, diastolic function was impaired only in the patients without redistribution. The RV contractile reserve in the patients without redistribution was less than in those with it. Thus, RV systolic function was maintained in the patients with anteroseptal infarction, but contractile reserve deteriorated only in severe septal ischemia. Similarly, diastolic function was maintained in mild septal ischemia, but impaired in severe septal ischemia. We concluded that RV systolic and diastolic functions are closely related to interventricular septal ischemia.

Centrally induced vasopressor responses to ouabain in DOCA-salt hypertensive rats

To investigate the effect of inhibition of cerebral Na+, K+-ATPase on cardiovascular regulation ouabain was injected into the lateral ventricle or the posterior hypothalamus in either conscious or urethane anaesthetised, deoxycorticosterone-salt hypertensive (DOCA) and sham operated (sham) rats. Ouabain injected intracerebroventricularly produced dose dependent vasopressor responses and tachycardia in the conscious rat; the magnitude of the pressor response was consistently larger in DOCA than in sham rats. In anaesthetised rats the pressor responses were accompanied by corresponding increases in abdominal sympathetic nerve activity. Thus the magnitude of the pressor responses, tachycardia, and the increases in nerve activity was again significantly greater in DOCA than in sham rats. Intrahypothalamic injections of ouabain produced pressor responses that were accompanied by consistent increases in both heart rate and abdominal sympathetic nerve activity in anaesthetised rats. In contrast to the intracerebroventricular injections the percentage increases from baseline blood pressure were significantly greater in sham than in DOCA rats at 5 min after injection. These results indicate that the centrally induced vasopressor response to ouabain, via the periventricular or bulbospinal system or both, is increased in DOCA-salt hypertensive rats whereas the pressor mechanism via the posterior hypothalamus is suppressed in DOCA rats.

[Clinical utility of spatial color mapping vectorcardiography in diagnosing myocardial infarction: comparison with 201Tl scintigraphy]

The feasibility of spatial color mapping vectorcardiography in diagnosing the site and extent of the old myocardial infarct was evaluated in comparison with 201T1 scintigraphy. Vectorcardiographic data made by Frank's technique were entered in the personal computer and the QRS complexes were plotted over 112 points crossing the latitude of each 20 (from 20N to 80S) degrees and longitude of each 20 degrees from 20W to 20E on the spherical body. Eight colors were assigned according to the direction of the QRS vector. To construct a territorial map, the apical, then, the septal, anterior, lateral, inferior and posterior portions were determined from the normal 201Tl scintigrams. Myocardial images obtained in the anterior, left anterior oblique and lateral projections were analyzed by the circumferential profile curve. Diagnostic specificity for infarction was greater than 60%, and especially high (90%) in the anterior, apical and lateral regions, but relatively low (50%) in the septal, inferior and posterior regions. Accuracies exceeded 64%. The infarcted areas assessed by spatial color vectorcardiography agreed with those assessed by 201T1 myocardial scintigraphy. Thus, spatial color vectorcardiography was simple and useful for diagnosing the site and extent of myocardial infarction.

[The source and significance of increased urinary dopamine excretion during sodium loading in rats]

To investigate the source and physiological significance of urinary free dopamine (f-DA) in high sodium diet (8% NaCl) loading, the effects of renal denervation and administration of carbidopa, an inhibitor of peripheral dopa decarboxylase, on urinary f-DA excretion were studied in male Wistar rats. Carbidopa was orally administered in a dose of 20mg/kg every 12h. To ascertain the extent of denervation, kidney norepinephrine was measured. Catecholamines were assayed by HPLC with electrochemical detection. Urinary f-DA and sodium excretion were significantly increased in response to the added NaCl. There were few effects of renal denervation on urinary excretion of f-DA and sodium in high sodium diet loading, whereas carbidopa caused a significant fall not only in urinary f-DA excretion but also in urinary sodium excretion. A highly significant correlation was also found between sodium excretion and f-DA excretion on the 5th day of carbidopa treatment. The data indicates that urinary f-DA in a high sodium diet is mainly derived from the renal tubular cells but not from renal nerves and that f-DA may be an important natriuretic hormone.

Effect of inhibition of Na+-K+ ATPase on the prostacyclin generation of cultured human vascular endothelial cells

Prostacyclin (PGI2) generation of cultured human vascular endothelial cells (VEC) was observed coincidentally with the increase of 45Ca net influx. Ca ionophore A23187 enhanced not only PGI2 generation and 45Ca net influx but also 45Ca efflux. PGI2 generation was completely abolished by the pretreatment with Ca++ immobilizer, TMB-8. A Na+-K+ ATPase inhibitor, ouabain increased 45Ca net influx, but decreased 45Ca efflux, and enhanced PGI2 generation. These observation indicate that PGI2 generation of VEC may be regulated by not only Ca++ but also Na+, and it was suggested that enhanced PGI2 generation by ouabain might be derived from the increased cytosolic Ca++concentration by the decreased Ca++ efflux, and it was considered to be originated from the suppression of Na+-Ca++ exchange systems by the increased intracellular Na+ concentration via inhibition of Na+-K+ ATPase activity by ouabain. Enhancement of PGI2 generation of VEC by the increased ouabain like substances (OLS) in hypertension is suspected to be beneficial on the maintenance of vascular homeostasis.

Regulation of prostacyclin generation by angiotensin converting enzyme related substances in cultured human vascular endothelial cells

The regulation of prostacyclin (PGI2) generation by angiotensin I-converting enzyme (ACE) related substances was investigated using cultured human vascular endothelial cells. Angiotensin I (AI) or bradykinin (BK) increased PGI2 generation and ACE activity, while the ACE inhibitor, captopril decreased both of them, and angiotensin II (AII) did not show any effect. The increasing rate of PGI2 generation induced by AI or BK was not affected by the pretreatment with captopril. These results suggest that the accumulation of AI or BK via the inhibition of ACE by captopril did not cause the enhancement of PGI2 generation. Rather, it was proposed that the enhanced PGI2 generation by AI or BK might be regulated by ACE activation derived from these substances, as an autoregulation mechanism.

Involvement of dopamine in development of hypertension in spontaneously hypertensive rat: effect of carbidopa, inhibitor of peripheral dopa decarboxylase

The demonstration of acceleration of hypertension was investigated in spontaneously hypertensive rats (SHR) treated with carbidopa, inhibitor of peripheral dopa decarboxylase. Oral administration of carbidopa to young SHR for 4 weeks accelerated significantly (P less than 0.05) development of hypertension as compared to SHR treated with vehicle. Urinary excretion of dopamine (DA) (P less than 0.01) and renal content of DA (P less than 0.02) were significantly decreased by carbidopa treatment. Urinary excretion of sodium (P less than 0.05) was significantly decreased and renal content of norepinephrine (NE) (P less than 0.01) was significantly increased by carbidopa. Urinary excretion of NE and epinephrine (E) did not change during the experimental period. Negative correlation between systolic blood pressure and urinary excretion of sodium (P less than 0.05) or dopamine (P less than 0.01) and positive correlation between systolic blood pressure and renal content of NE (P less than 0.05) were significantly observed in both groups of SHR treated with carbidopa and with vehicle for 4 weeks. These results suggest that decreased DA biosynthesis in peripheral tissues accelerates development of hypertension mediated by decrease of natriuresis and enhanced release of NE in the kidneys of SHR. DA plays an important role in regulation of blood pressure, and reduced dopaminergic mechanisms enhance blood pressure in SHR.

Effect of decreased dopamine synthesis on the development of hypertension induced by salt loading in spontaneously hypertensive rats

To clarify role of dopamine in the development of hypertension, the effect of a dopamine synthesis inhibitor on blood pressure and urinary output of catecholamines was investigated in spontaneously hypertensive rats (SHR) fed with high sodium diet. Rats were orally given carbidopa, an inhibitor of peripheral DOPA decarboxylase, or the vehicle for 4 weeks. Carbidopa administration accelerated significantly the development of hypertension as compared to the control SHRs with the vehicle. Carbidopa administration resulted in a significant decrease of urinary excreted sodium, urinary dopamine and renal content of dopamine. Conversely, carbidopa administration resulted in a significant increase of urinary excreted norepinephrine, urinary epinephrine and renal content of norepinephrine as compared with control SHRs. These results suggest that decreased dopamine synthesis in kidneys and probably other peripheral tissue accelerates the development of hypertension, mediated by a decrease of natriuresis and an enhancement of sympatho-adrenomedullary activity. Dopamine plays an important role in its protective action against the development of hypertension enhanced by salt loading, and decreased dopaminergic mechanisms accelerated hypertension in SHR.

Role of renal nerves and dopamine on prostaglandin E release from the kidney of rats

The aim of the study is to investigate the role of renal nerves and dopamine (DA) on urinary excretion of prostaglandin E (PGE) released from kidney with or without salt loading in rats. After excessive intake of high Na, urinary excretions of PGE and DA enhanced as compared with those of basal Na. In rats with renal denervation, urinary excretion of PGE and norepinephrine decreased in salt loading, and urinary Na excretion increased. Urinary PGE excretion was also enhanced by treatment of bromocriptine accompanying with augmented natriuresis. Urinary PGE excretion was suppressed by treatment of carbidopa, which also suppressed the urinary excretion of DA. These results suggest that the renal adrenergic nerve and tubular DA in kidney play an important role on the release of PGE and that these mechanisms in PGE release from kidney augment in salt loading.

Attenuation of hypothalamo-sympathetic hyperactivity by renal denervation in experimental hypertensive rats

To clarify the effect of renal nerves on hypothalamic cardiovascular regulation in hypertension, posterior hypothalamus was electrically stimulated in renal denervated SHR (RD-SHR) and DOCA hypertensive (RD-DOCA) rats during recording blood pressure and sympathetic nerve activity. In urethane anesthetized SHR, mean blood pressure was not different between RD- and sham-operated SHR 48 hours after denervation, but two weeks later, blood pressure was lower in RD-SHR. Pressor and sympathetic nerve responses to hypothalamic stimulation were partly attenuated 48 hours after denervation, but two weeks later, attenuation was strong. The development of hypertension was abolished during two weeks observation in RD-SHR. In DOCA hypertensive rats, the development of hypertension was significantly inhibited by renal denervation. Pressor and sympathetic nerve responses to hypothalamic stimulation were significantly diminished in RD-DOCA rats. Water intake and urine volume was identical in both groups. These results suggest that renal denervation inhibited the development of hypertension accompanied with the inhibition of hypothalamo-sympathetic nerve system, furthermore, it is indicated that hypothalamic cardiovascular regulation controlled by afferent renal nerve could contribute to the development of hypertension in SHR and DOCA hypertensive rats.

Central effect of captopril on baroreflex

To clarify effect of converting enzyme inhibitors (CEI) on heart rate regulation, captopril (2 mg/kg) was injected intravenously (i.v.) with or without pretreatment of atropine and also responses to intracisternal (i.c.) injections were examined. Captopril induced bradycardia with lowering blood pressure, and this bradycardia was abolished by pretreatment of atropine. Reduction of heart rate by i.c. injection of captopril was significantly larger than those of i.v. injection. Furthermore, to determine whether CEI can modify baroreflexes centrally, the aortic depressor nerve (ADN) was stimulated electrically in captopril treated rats. Vasodepressor and sympatho-inhibitory responses induced by ADN stimulation were significantly attenuated by captopril, while the bradycardiac response was not changed. These findings suggest that captopril attenuated centrally vasodepressor and sympatho-inhibitory responses of the baroreflex and activated centrally cardiac vagal efferent activity.

[Left ventricular function during atrial fibrillation assessed by left ventricular function curve using ECG-gated blood pool scintigraphy]

Cardiac function is difficult to assess in patients with atrial fibrillation due to the widely fluctuating cycle lengths resulting in variable ventricular hemodynamics. With respect to ECG-gated blood pool scintigraphy, distortion of the time activity curve occurs due to a summation of irregular cycle lengths. Therefore, performing such a study has been regarded meaningless. To evaluate left ventricular function during atrial fibrillation using scintigraphic technique, a new processing algorithm was devised to make multiple gated images which are discriminated by the preceding R-R interval, and left ventricular filling and function curves were established. The left ventricular filling curve, obtained by plotting end-diastolic volume against the preceding R-R intervals demonstrated an impairment of blood filling in cases of mitral stenosis and constrictive pericarditis, which resolved after mitral commissurotomy in case of mitral stenosis. The left ventricular function curve, established by plotting stroke volume against end-diastolic volume, was analyzed according to indices such as "slope" and "position". Both of these indices were significantly reduced in relation to the severity of heart failure according to the NYHA's functional classification and cardiomegaly on chest radiography. On individual comparisons of underlying diseases, the indices decreased in the following order; lone atrial fibrillation, hyperthyroidism, aging, hypertension, mitral valve disease, ischemic heart disease, dilated cardiomyopathy and aortic regurgitation. The indices correlated closely with ejection fraction. In cases of mitral regurgitation, however, the function curves were situated to the right and above those of lone atrial fibrillation and decreased in slope despite the fairly well-maintained ejection fraction. After treatment with digitalis and/or diuretics, the function curves shifted to the left and upward. In conclusion, left ventricular filling and function curves based on a newly-devised algorithm of ECG-gated blood pool scintigraphy are of considerable clinical value in evaluating cardiac performance in patients with atrial fibrillation. They are widely applicable to the assessment of therapeutic and interventional effects.

Augmented vasodepressor and sympathetic responses to intracerebroventricular injections of diltiazem, a calcium channel blocker, in DOCA-salt hypertensive rats

The role of the calcium ion in central cardiovascular regulation was investigated by injecting a calcium channel blocker, diltiazem, intracerebroventricularly (i.c.v.) in urethane-anaesthetized, DOCA-salt hypertensive rats. This produced a fall in blood pressure and bradycardia with corresponding decreases in abdominal sympathetic nerve activity. However, a similar amount of diltiazem injected intravenously (i.v.) did not affect abdominal sympathetic nerve activity despite an accompanying vasodepression. The responses to i.v. injections of diltiazem were not different between the two groups; however, the magnitude of the blood pressure fall, bradycardia and sympathetic inhibition with i.c.v. injections was greater in the DOCA rats than in the sham-operated animals. These results suggest that diltiazem causes the central nervous system to decrease the sympathetic nerve outflow. The augmented central vasodepressor responses to diltiazem in DOCA-salt hypertensive rats may indicate that calcium metabolism in the central nervous system is disrupted and that this is of importance in the pathogenesis of DOCA-salt hypertension in rats.

Hypotensive responses to centrally administered taurine in DOCA-salt hypertensive and spontaneously hypertensive rats

The present study was designed to investigate the short-term effects of intracerebroventricularly-administered taurine in DOCA-salt hypertensive (DOCA), spontaneously hypertensive (SHR) and their respective normotensive control rats anesthetized with urethane. Blood pressure, heart rate and sympathetic nerve activity were consistently decreased following the injection of taurine 150 micrograms per rat in hypertensive rats as well as in normotensive controls of the two groups. Percent changes from the baselines in blood pressure, heart rate and sympathetic nerve activity were significantly larger in DOCA-salt hypertensive rats than those in sham operated rats. In contrast, percent changes in blood pressure and sympathetic nerve activity were not significantly different between spontaneously hypertensive rats and normotensive wistar kyoto rats. These result show that the responses of blood pressure, heart rate and sympathetic nerve activity to intracerebroventricular taurine are different between spontaneously hypertensive rats and DOCA-salt hypertensive rats. It appears that augmented vasodepressor responses to taurine in DOCA-salt hypertensive rats, as compared to spontaneously hypertensive rats, are due to enhanced inhibition of the sympathetic outflow.

Evidence for a digitalis-like substance in the hypothalamo-pituitary axis in rats

The origin of an endogenous digitalis-like substance in rats was investigated. The tissue content of the substance measured by radio-immunoassay was highest in the pituitary gland, with a decreasing gradient through the hypothalamus, forebrain, cerebellum, brain stem, heart, liver and kidney. Sodium loading decreased the content in the hypothalamus and increased the urinary excretion of the substance. The urinary output of the substance decreased after electrical lesions of the anteroventral third ventricle in the brain. The content increased in the hypothalamus and decreased in the plasma when the axonal flow of neurosecretion was interrupted with intracerebroventricular injections of colchicine. These results suggest that the digitalis-like substance could be produced in the hypothalamus and secreted from the pituitary gland like vasopressin, and that sodium loading increases the turnover of the substance in the hypothalamus.

Attenuated development of hypertension by chronic administration of bromocriptine in Doca-salt hypertensive rats

The aim of the study was to investigate whether or not the development of hypertension is influenced by chronic treatment with bromocriptine and/or domperidone. Rats treated with DOCA-salt were divided into 4 groups: control with vehicle, bromocriptine, bromocriptine with domperidone, and domperidone. Increased blood pressure by DOCA-salt treatment was significantly suppressed by treatment with bromocriptine and this bromocriptine suppression was significantly blocked by treatment with domperidone. Increased urinary excretion of norepinephrine by DOCA-salt treatment was significantly suppressed by bromocriptine and the inhibiting effect of bromocriptine disappeared with domperidone. In the four groups of rats, there were significant correlations between systolic blood pressure and urinary excretion of norepinephrine, systolic blood pressure and urinary excretion of epinephrine, and urinary excretion of dopamine and sodium. These results suggest that the chronic effect of bromocriptine is to suppress development of DOCA-salt hypertension, mainly through peripheral mechanisms which are involved in the decreased release of norepinephrine.

Hypotension and hypothalamic depression produced by intracerebroventricular injections of GABA in spontaneously hypertensive rats

To determine the central effects of 4-Amino-n-butyric acid (GABA), pressor and sympathetic nerve responses to electrical stimulation of the ventromedial hypothalamus were recorded following the intracerebroventricular (ICV) injection of GABA. In normotensive Wistar rats, anesthetized with urethane, ICV injections of GABA (50-200 micrograms) reduced sympathetic nerve activity, arterial blood pressure, and heart rate in a dose-dependent manner. Graded electrical stimulation of the ventromedial hypothalamus (50, 100, 150 microA) increased not only mean blood pressure but also the rate of sympathetic nerve firing, and both responses were attenuated by GABA pretreatment (100, 200 micrograms, ICV). In spontaneously hypertensive rats (SHR), ICV-injected GABA also reduced sympathetic and cardiovascular activity, but the magnitude of depressor responses was significantly larger in SHR than in normotensive Wister Kyoto controls (WKY). Pressor and sympathetic nerve responses elicited by ventromedial hypothalamic stimulation were initially larger in SHR than in WKY, but upon subsequent ICV injection of GABA, hypothalamic responsiveness in SHR was inhibited more prominently and became comparable to that in WKY. These results suggest that by depressing hypothalamic function, centrally injected GABA decreases sympathetic nerve activity to thereby lower blood pressure and heart rate, and in SHR, ICV-injected GABA reversed hypothalamo-sympathetic hyperactivity and thus attenuated hypertension.