THU0231 IL-2 DRIVES THE CONVERSION OF T FOLLICULAR HELPER TO T FOLLICULAR REGULATORY CELLS THROUGH EPIGENETIC MODIFICATION IN SYSTEMIC LUPUS ERYTHEMATOSUS

Background:

Systemic lupus erythematosus (SLE) is a complex polygenic autoimmune disease characterized by immune-system aberrations. Among several types of immune cells, T follicular helper (Tfh) cells promote autoantibody production, whereas T follicular regulatory (Tfr) cells suppress Tfh-mediated antibody responses.(1)

Objectives:

To identify the characteristics of Tfr cells and to elucidate the mechanisms of conversion of Tfh cells to Tfr cells, we probed the phenotype of T helper cells in patients with SLE and underlying epigenetic modifications by cytokine-induced signal transducer and activators of transcription (STAT) family factors.

Methods:

Peripheral blood mononuclear cells from SLE patients (n=44) and healthy donors (HD; n=26) were analyzed by flow cytometry. Memory Tfh cells were sorted and cultured under stimulation with T cell receptor and various cytokines. Expression of characteristic markers and phosphorylation of STATs (p-STATs) were analyzed by flow cytometry and quantitation PCR. Histone modifications were evaluated by chromatin immunoprecipitation.

Results:

The proportion of CXCR5+FoxP3+Tfr cells in CD4+T cells tended to increase (2.1% vs 1.7%, p=0.17); however, that of CD4+CD45RA-FoxP3hiactivated Tfr cells in Tfr cells was decreased (4.8% vs 7.1%, p<0.05), while CD4+CD45RA-FoxP3lownon-suppressive Tfr cells was increased (50.1% vs 38.2%, p<0.01) in SLE compared to HD. The percentage of PD-1hiactivated Tfh cells was significantly higher in SLE compared to HD (15.7% vs 5.9%, p<0.01). Furthermore, active patients had a higher ratio of activated Tfh/Tfr cells compared to inactive patients. In vitro study showed that IL-2, but not other cytokines such as TGF-β1, IL-12, IL-27, and IL-35, induced the conversion of memory Tfh cells to functional Tfr cells characterized by CXCR5+Bcl6+Foxp3hipSTAT3+pSTAT5+cells. The loci ofFOXP3at STAT binding sites were marked by bivalent histone modifications. After IL-2 stimulation, STAT5 directly bound on FOXP3 gene loci accompanied by suppressing H3K27me3. Finally, we found that serum level of IL-2 was decreased in SLE and that stimulation with IL-2 suppressed the generation of CD38+CD27+B cells by ex vivo coculture assay using Tfh cells and B cells isolated from human blood.

Conclusion:

Our findings indicated that the regulatory function of Tfr cells is impaired due to the low ability of IL-2 production and that IL-2 restores the function of Tfr cells through conversion of Tfh cells to Tfr cells in SLE. Thus, the reinstatement of the balance between Tfh and Tfr cells will provide important therapeutic approaches for SLE.

References:

[1]Deng J, Wei Y, Fonseca VR, et al. T follicular helper cells and T follicular regulatory cells in rheumatic diseases. Nat Rev Rheumatol. 2019; 15 (8): 475-90.

Disclosure of Interests: :

He Hao: None declared, Shingo Nakayamada Grant/research support from: Mitsubishi-Tanabe, Takeda, Novartis and MSD, Speakers bureau: Bristol-Myers, Sanofi, Abbvie, Eisai, Eli Lilly, Chugai, Asahi-kasei and Pfizer, Yamagata Kaoru: None declared, Naoaki Ohkubo: None declared, Shigeru Iwata: None declared, Yoshiya Tanaka Grant/research support from: Asahi-kasei, Astellas, Mitsubishi-Tanabe, Chugai, Takeda, Sanofi, Bristol-Myers, UCB, Daiichi-Sankyo, Eisai, Pfizer, and Ono, Consultant of: Abbvie, Astellas, Bristol-Myers Squibb, Eli Lilly, Pfizer, Speakers bureau: Daiichi-Sankyo, Astellas, Chugai, Eli Lilly, Pfizer, AbbVie, YL Biologics, Bristol-Myers, Takeda, Mitsubishi-Tanabe, Novartis, Eisai, Janssen, Sanofi, UCB, and Teijin

Efficacy and safety of anti-CD20 antibody rituximab for patients with refractory systemic lupus erythematosus

Objective

We examined the efficacy and safety of rituximab in patients with refractory systemic lupus erythematosus (SLE).

Methods

The study enrolled 63 SLE patients who were treated with rituximab between 2002 and 2015. The participants underwent a battery of tests before treatment and at one year. Treatment ranged from two to four times at 500 or 1000 mg.

Results

Baseline characteristics were males:females = 6:57, age 33.9 years, and disease duration 87.2 months. The primary endpoint: The rate of major clinical response (MCR) was 60% while the partial clinical response (PCR) was 25%. Thirty of 36 (83%) patients with lupus nephritis (WHO II: 2, III: 5, IV: 22, V: 4, IV+V: 2, not assessed: 1) and 22 of 24 patients (92%) with neuropsychiatric SLE, who could be followed at one year, showed changes from BILAG A or B score to C or D score at one year. Multivariate analysis identified high anti-dsDNA antibody and shorter disease duration as significant determinants of MCR at one year. Repeat examination was conducted at five years. Primary failure was recorded in 8.8% and secondary failure in 32.4% (time to relapse: 24.4 months). Rituximab was well tolerated although 65 adverse events, mostly infections, were recorded within one year.

Conclusion

Rituximab is potentially efficacious for the treatment of patients with refractory SLE.

Middle-term results of endovascular aneurysm repair in Japan: does intraoperative endovascular management against the hostile aneurysmal neck prevent the proximal type I endoleak?

AIM

Endovascular aneurysm repair (EVAR) was first approved in Japan in 2007. In order to avoid the learning curve generally seen in the initial stages of implementation, we have aimed for procedural perfection. As the proximal type I endoleak (EL) is associated with a higher risk of late conversion and rupture, so we have treated the intraoperative type I EL scrupulously. The hostile neck, which is known to be a risk for perigraft leakage, is the focus of this study. We showed both the middle-term results of EVAR in our country and the possible necessity of intraoperative management for the hostile neck.

METHODS

From a consecutive series of 134 patients who underwent EVAR of abdominal aortic aneurysms, 129 cases in which contrast agent was used intraoperatively were selected. All cases had at least 12-month follow-up postoperatively (12-40 months). Of the 129 selected cases, 49 cases (37%) that did not fulfill the commercially recommended criteria of the aneurysmal neck (length <15 mm and angle >60° of the aneurysm or >45° of the suprarenal aorta) were assigned to the off-label group. The other 80 cases were assigned to the on-label group. We carefully observed the completion angiography and when we found or suspected a type I EL, we performed a re-touch up, changed to a non-compliant balloon, and used a supportive device, such as a PalmazTM stent or aortic cuffs, in sequence.

RESULTS

No postoperative type I ELs were detected within the follow-up period. Intraoperative type I ELs were detected more frequently in the off-label group (51%) than the on-label group (20%) (P<0.01). The rate of type I EL in the off-label group in terms of the neck length criteria (11/14 cases) was higher than that in the on-label group (30/115 cases) (P<0.01). In terms of the neck angle, patients in the off-label group had a greater tendency to develop the type I EL than those in the on-label group (18/42 vs. 23/87 cases) (P=0.06).

CONCLUSION

Off-label usage regarding aneurysmal neck length and angle tends to be incomplete without additional procedures. Conversely, various techniques, including non-compliant balloon usage and aortic stenting or cuffs, produce good results for the intraoperative type I EL. We found a relationship between the neck condition and the intraoperative type I EL, and showed the importance of strictly obeying our simple algorithm against the proximal type I EL.

Winter lipid depletion of juvenile walleye pollock Theragra chalcogramma in the Doto area, northern Japan

Seasonal variation in body size and nutritional condition of juvenile walleye pollock Theragra chalcogramma was examined to elucidate the mechanism underlying their first-winter survival on the continental shelf of the Doto area, northern Japan, based on monthly samples collected over 2 years. Stored lipid mass was highest during autumn, but 93% (2004) and 80% (2005) of lipids were exhausted by the onset of winter. Lipid levels in the winter of 2004 remained low (7-14% of the autumnal maximum), and there was reduced growth rate until the spring, whereas in 2005 lipid levels were higher and more variable (10-46% of the maximum) and some growth occurred. An analysis of the allometric relationships between body size and stored energy showed that larger individuals accumulated disproportionately more energy in the autumn, but the advantage disappeared prior to the winter. In January 2004, stored lipid energy was low throughout the Doto continental shelf relative to the continental slope area. These results suggest that winter feeding opportunities on the shelf are severely limited but not completely absent. Previous studies have shown that winter temperatures on the shelf are lower than those in the slope area. It is possible that juvenile T. chalcogramma survive winter on the shelf without a high level of pre-winter lipid storage because the occasional feeding in the cold shelf water benefits energy conservation.

Deduced primary structure of two forms of vitellogenin in Japanese common goby (Acanthogobius flavimanus)

Complete nucleotide sequences of two forms of vitellogenin (Vg) cDNA in Japanese common goby were determined from a liver cDNA library of E(2)-treated male fish. These two Vg cDNAs contained complete open reading frames encoding 1664 and 1238 amino acid residues including signal peptides, respectively. From comparison of the deduced amino acid sequences of both Vgs and the partial amino acid sequences of the yolk proteins, the longer sequence was concluded to be cDNA of the Vg-530 and the shorter one was that of the Vg-320 of the Japanese common goby which were reported in our previous paper. The deduced sequence of Vg-530 without signal peptide was arranged by lipovitellin heavy-chain (LvH), phosvitin (Pv), lipovitellin light-chain (LvL), and beta'-component beta'-c) domains from the N-terminus, and showed a range of 40-45% sequence identity to those of other fish. Furthermore, the deduced sequence of Vg-320 showed no obvious Pv domain, has a shortened C-terminal coding region after the LvH domain, and showed a close similarity to the phosvitin-less Vg of zebrafish. Moreover, biochemical analysis of the yolk proteins verified that Vg-530 cleaves into the Lv-Pv complex (molecular mass: 470 kDa) and beta'-c (33 kDa), while Vg-320 showed no change when incorporated into oocytes. The present study demonstrated the existence of the two different forms of Vgs at both the cDNA and protein level, and showed molecular alteration of the two Vgs during vitellogenesis. Two Vg sequence data will aid in designing nucleotide probes for detecting Vg gene expressions as a biomarker of environmental estrogens.

Activated cAMP-response element-binding protein regulates neuronal expression of presenilin-1

Upon binding to the cAMP-response element of a gene's promoter, the transcription factor known as cAMP-response element-binding protein (CREB) facilitates transcription of many different neuronal genes including those involved with synaptic function. Based on our previous reports of gene structure (GenBank accession number AF029701 ), we now demonstrate that activated CREB binds to the proximal promoter of the human presenilin-1 (PS-1) gene to activate PS-1 transcription in rat and in human neuronal cells. Specific stimulation of the N-methyl-d-aspartate subtype of neuronal glutamate receptors activates CREB and results in increased PS-1 expression. Similarly, treatment with brain-derived neurotrophic factor activates CREB and increases PS-1 expression in a dose-dependent fashion. By using adenovirus vectors expressing dominant negative forms of CREB, we were able to show that induction of PS-1 expression requires the activation of CREB. Conversely, constitutive expression of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) results in activation of CREB and increased PS-1 expression that can be blocked by the addition of selective MEK inhibitors. Our findings suggest a hypothesis where stimulation of N-methyl-d-aspartate receptors signals CREB activation to enhance PS-1 gene product expression that contributes to normal neuronal functions.

Apolipoprotein E4 stimulates cAMP response element-binding protein transcriptional activity through the extracellular signal-regulated kinase pathway

Inheritance of the epsilon4 allele of the apolipoprotein E gene (APOE4) is a major risk factor for the development of Alzheimer's disease (AD). Although the association between APOE4 and AD is well documented, the mechanism by which apolipoprotein E exerts an isoform-specific effect on neurons in disease is unknown. In this report, we demonstrate that apoE4 stimulates the transcriptional activity of cAMP-response element-binding protein (CREB) by activating the extracellular signal-regulated kinase (ERK) cascade in rat primary hippocampal neurons. In contrast, apoE3 was unable to stimulate CREB transcriptional activity and unable to activate the ERK pathway. Elevation of intracellular Ca(2+) levels are also involved because treatment with receptor-associated protein, nifedipine, MK801, removal of Ca(2+) from the medium and dantrolene all served to inhibit calcium elevation and attenuate the activation of CREB. Treatment with an apoE peptide was also found to facilitate transcription of the CREB-dependent genes, c-fos and Bcl-2. In contrast to treatment with apoE3, our findings suggest apoE4 and apoE-peptide induce a novel signaling pathway.

Serial change in the atrial transport function after the radial incision approach

BACKGROUND

The left atrial transport function recovers slowly over several months after the maze procedure (Maze), but remains at a low level even during the long-term postoperative period. Because the Maze leaves an insufficient left atrial transport function, patients may still be prone to thromboembolism after the Maze. The radial incision approach (Radial) has been shown to preserve greater atrial transport function than does the Maze in the early postoperative period.

METHODS

To examine the serial change in the atrial transport function after the Radial, out of 32 patients who underwent the Radial, 15 patients were assessed by transthoracic Doppler echocardiography 1, 3, 6, and 12 months after surgery. The atrial filling fraction and peak A/E velocity ratio were determined from the flow-velocity spectra across the mitral and tricuspid valves. The incidence of thromboembolic events was examined in 21 patients who were followed for more than 3 months after the Radial. The data were compared with data obtained from 13 patients after (41 +/- 6 months) the Maze III procedure.

RESULTS

The left atrial transport function after the Radial increased within 3 months to a significantly greater level than did that after the Maze in the longterm. The atrial filling fraction was 28.2% +/- 7.9% at 3 months after the Radial and 15.1% +/- 4.0% at 41 months after the Maze (p < 0.01). The peak A/E ratio was 0.52 +/- 0.18 at 3 months after the Radial and 0.25 +/- 0.07 at 41 months after the Maze (p < 0.01). This increased atrial transport function was maintained for an extended period after the Radial. There were no thromboembolic events in any of the patients after the Radial or Maze, irrespective of postoperative anticoagulant therapy.

CONCLUSIONS

The Radial approach prevents thromboembolism by restoring sufficient atrial transport function more effectively and faster than does the Maze.

Is median sternotomy invasive? A comparison between minimally invasive direct coronary artery bypass and off-pump bypass

Although minimally invasive direct coronary artery bypass (MIDCAB) eliminates the need for median sternotomy and cardiopulmonary bypass, its indications are limited. Conversely, coronary artery bypass without cardiopulmonary bypass (off-pump bypass) enables complete surgical revascularization under an optimal surgical field established by median sternotomy, even if patients have multivessel disease. The present study was designed to determine the invasiveness of median sternotomy by comparing 11 patients who underwent MIDCAB and 5 who underwent off-pump bypass between May 1997 and April 1998. There were no significant differences between the MIDCAB group and the off-pump group in age, being 57 +/- 11 vs 66 +/- 8 years old, the operative time, being 321 +/- 149 vs 441 +/- 205 min, the number of grafts, being 1.0 vs 1.4/patient, peak creatine kinase (CK) values, being 662 +/- 436 vs 609 +/- 56 IU/l, the peak CK-muscle-brain values, being 12 +/- 9 vs 16 +/- 5 IU/l, and the postoperative blood loss, being 369 +/- 198 vs 541 +/- 204 ml. Although there was no significant difference in peak C-reactive protein, at 17 +/- 5 vs 20 +/- 2 mg/dl, the periods declining within the normal ranges were shorter in the MIDCAB group than in the off-pump group, at 7 +/- 1 vs 15 +/- 2 days (P > 0.01). The hospital stay was almost the same in both groups, at 16 +/- 8 vs 26 +/- 14 days. These findings suggest that off-pump bypass is more invasive than MIDCAB, which may be attributed to the median sternotomy.

Importance of preoperative marking for minithoracotomy and for internal thoracic artery harvesting in minimally invasive direct coronary artery bypass grafting

Minimally invasive direct coronary artery bypass has the potential to cause an anastomotic failure because of a limited exposure of the operative field and the difficulty of internal thoracic artery harvesting. In the present study, the importance of preoperative marking for an accurate minithoracotomy location and a successful internal thoracic artery harvest was assessed. A paperclip was placed on the left nipple and a chest X-ray was performed in the supine position. By aligning the position of the paperclip to the location of the left anterior descending coronary artery from a coronary arteriogram frontal view, the intercostal space for the minithoracotomy was thus determined. Marking the incisional intercostal space during preoperative left internal thoracic arteriography revealed the number and location of the internal thoracic artery branches at the beginning of the harvest. This preoperative marking technique allowed for a more adequate exposure of the operative field and an easier internal thoracic artery harvest which therefore contributed to an improvement in the operative results.

Spontaneous closure of a large tracheal fistula due to descending necrotizing mediastinitis

We present a case of a 77-year-old man who had a large tracheal fistula due to descending necrotizing mediastinitis. He underwent long-term care with a respirator after mediastinal drainage operations. The fistula was covered spontaneously with the anterior wall of the esophagus 1.5 months postoperatively.

Role of off-pump coronary artery bypass grafting in patients with malignant neoplastic disease

Although the long-term benefits of conventional coronary artery bypass grafting (CABG) are obvious, postoperative morbidity and mortality and the length of recovery associated with cardiopulmonary bypass are the main concerns of cardiac surgeons and cardiologists. The aim of this study was to demonstrate the effectiveness and advantage of the off-pump CABG for patients with concomitant malignant disorders requiring myocardial revascularization. From March 1997 to February 1999, 51 patients underwent off-pump CABG. Of these, there were 9 patients who had concomitant malignant disease requiring noncardiac surgery: gastric cancer (4), urinary bladder cancer (2), cholangioma (1), lung cancer (1) and colon cancer (1). Off-pump CABG was performed through a sternotomy, left thoracotomy or subxiphoid incision. Five patients received single grafting and 4 received double. The mean operative time for the off-pump CABG was 167 min. The total amount of bleeding during the off-pump CABG was 450-890 ml. Simultaneous noncardiac operations were carried out in 5 patients. The other 4 patients underwent subsequent operations for the malignancy uneventfully. In contrast, of the 4 patients with concomitant malignant disorders who underwent standard CABG during the period before the use of off-pump CABG, 2 died without undergoing the subsequent noncardiac operation. Off-pump CABG is quite efficient and is of great advantage in patients with malignancy who require myocardial revascularization in addition to noncardiac surgery for the cancer.

Two forms of vitellogenin, yielding two distinct lipovitellins, play different roles during oocyte maturation and early development of barfin flounder, Verasper moseri, a marine teleost that spawns pelagic eggs

Two forms of vitellogenin (Vg), Vg A and Vg B, were identified in serum from estrogen-treated barfin flounder (Verasper moseri). Structural changes of lipovitellins (Lvs) derived from the two Vgs were examined during vitellogenesis and oocyte maturation. Two Lvs, vLv A and vLv B, were identified electrophoretically and immunologically in postvitellogenic oocytes. Each appeared to be composed of distinct heavy chains (vLvH A, M(r) 107,000, and vLvH B, M(r) 94,000) and light chains (vLvL A, M(r) 30,000, and vLvL B, M(r) 28,000) when analyzed by SDS-PAGE. Results from N-terminal amino acid sequencing and Western blotting using antisera to vLvH A and vLvH B verified that there are two Vg polypeptides in serum from estrogen-treated fish, Vg A (M(r) 168,000) and Vg B (M(r) 175,000), which give rise to vLvH A-vLvL A and vLvH B-vLvL B, respectively. N-terminal sequencing revealed two sequences for both phosvitin and beta'-component, supporting the concept of duality for all three classes of Vg-derived yolk proteins. During oocyte maturation, native dimeric vLv B was dissociated into a native M(r) 170,000 monomer (oLv B). Meanwhile, vLv A was extensively cleaved including complete degradation of vLvH A into free amino acids. We propose that the quantitative ratio of vLv A to vLv B in postvitellogenic oocytes regulates the buoyancy of the spawned pelagic eggs by controlling availability of free amino acids which function as osmotic effectors during oocyte hydration. The vLv A/vLv B ratio likely also controls the proportional availability of different types of nutrients, free amino acids versus Lv, for use during embryonic development.

Combined non-cardiac operations with minimally invasive direct coronary artery bypass grafting

We report two cases in which Minimally invasive direct coronary artery bypass grafting was followed by other non-cardiac operations in the same operative setting. A left internal thoracic artery-to-left anterior descending artery anastomosis was constructed through a left anterior thoracotomy in both patients. Immediately after Minimally invasive direct coronary artery bypass grafting, one patient underwent a pancreatoduodenectomy for a biliary duct carcinoma and the other patient received a prosthetic graft replacement for an abdominal aortic aneurysm. Minimally invasive direct coronary artery bypass grafting is advantageous in patients with significant coronary artery disease who have to undergo other non-cardiac surgeries.

Angiotensin II type 2 receptor is upregulated in human heart with interstitial fibrosis, and cardiac fibroblasts are the major cell type for its expression

The expression pattern of angiotensin (Ang) II type 2 receptor (AT2-R) in the remodeling process of human left ventricles (LVs) remains poorly defined. We analyzed its expression at protein, mRNA, and cellular levels using autopsy, biopsy, or operation LV samples from patients with failing hearts caused by acute (AMI) or old (OMI) myocardial infarction and idiopathic dilated cardiomyopathy (DCM) and also examined functional biochemical responses of failing hearts to Ang II. In autopsy samples from the nonfailing heart group, the ratio of AT1-R and AT2-R was 59% and 41%, respectively. The expression of AT2-R was markedly increased in DCM hearts at protein (3.5-fold) and mRNA (3.1-fold) levels compared with AMI or OMI. AT1-R protein and mRNA levels in AMI hearts showed 1.5- and 2.1-fold increases, respectively, whereas in OMI and DCM hearts, AT1-R expression was significantly downregulated. AT1-R-mediated response in inositol phosphate production was significantly attenuated in LV homogenate from failing hearts compared with nonfailing hearts. AT2-R sites were highly localized in the interstitial region in either nonfailing or failing heart, whereas AT1-R was evenly distributed over myocardium at lower densities. Mitogen-activated protein kinase (MAPK) activation by Ang II was significantly decreased in fibroblast compartment from the failing hearts, and pretreatment with AT2-R antagonist caused an additional significant increase in Ang II-induced MAPK activity (36%). Cardiac hypertrophy suggested by atrial and brain natriuretic peptide levels was comparably increased in OMI and DCM, whereas accumulation of matrix proteins such as collagen type 1 and fibronectin was much more prominent in DCM than in OMI. These findings demonstrate that (1) AT2-R expression is upregulated in failing hearts, and fibroblasts present in the interstitial regions are the major cell type responsible for its expression, (2) AT2-R present in the fibroblasts exerts an inhibitory effect on Ang II-induced mitogen signals, and (3) AT1-R in atrial and LV tissues was downregulated during chronic heart failure, and AT1-R-mediated functional biochemical responsiveness was decreased in the failing hearts. Thus, the expression level of AT2-R is likely determined by the extent of interstitial fibrosis associated with heart failure, and the expression and function of AT1-R and AT2-R are differentially regulated in failing human hearts.

Blood macrophage colony-stimulating factor and thrombin-antithrombin III complex concentrations in pregnancy and preeclampsia

Macrophage colony-stimulating factor (M-CSF) is a characteristic cytokine that plays an essential role in placenta maintenance, and thrombin-antithrombin III complex (TAT) is a hemostatic marker that is remarkably altered both in normal pregnancy and in preeclampsia. The present study was designed in order to show various levels of M-CSF and TAT in pregnancies. Peripheral blood was collected from 49 subjects, of whom 31 were normal pregnant women consisting of the four groups (namely 10th, 20th, 30th, and 38th weeks of gestation), 13 were preeclamptic pregnant women (37th week of gestation; mean blood pressure, 158/99 mm Hg), and 5 were nonpregnant controls. We compared blood M-CSF and TAT levels among them. Results showed that blood M-CSF and TAT levels increased significantly with gestational age. Furthermore, the ratio of increase in M-CSF was significantly lower than that in TAT in normal pregnant women compared with controls. In contrast, the ratio of increase in M-CSF was significantly higher than that in TAT in preeclamptic women compared with normal pregnant women. These results concerning the ratio of increase in M-CSF and TAT have not been reported. These findings show that M-CSF level increases significantly in preeclampsia even in its earlier stage, exhibiting a systolic blood pressure of less than 160 mm Hg.

Angiotensin type 2 receptors are reexpressed by cardiac fibroblasts from failing myopathic hamster hearts and inhibit cell growth and fibrillar collagen metabolism

BACKGROUND

Angiotensin (Ang) II type 1 receptor (AT1-R) induces cardiomyocyte hypertrophy and fibroblast proliferation, whereas the physiological role of AT2-R in cardiac remodeling remains poorly defined.

METHODS AND RESULTS

Using Bio14.6 cardiomyopathic (CM) hamsters, we found that AT2-R sites were increased by 153% during heart failure compared with F1B controls. AT1-R numbers were increased by 72% in the hypertrophy stage and then decreased to the control level during heart failure. Such differential regulation of AT2-R and AT1-R during heart failure was consistent with changes in the respective mRNA levels. Autoradiography and immunocytochemistry revealed that both AT2-R and AT1-R are localized at higher densities in fibroblasts present in fibrous regions. Surrounding myocardium predominantly expressed AT1-R, but the level of expression was less than that in fibrous regions. Cardiac fibroblasts isolated from CM hearts during heart failure but not from control hamsters expressed AT2-R (30 fmol/mg protein). Using the cardiac fibroblasts expressing AT2-R, we found that Ang II stimulated net collagenous protein production by 48% and pretreatment with an AT2-R antagonist, PD123319, evoked a further elevation (83%). Ang II-induced synthesis of fibronectin and collagen type I were enhanced by 40% and 53%, respectively, by pretreatment with PD123319. Ang II-induced DNA synthesis (assessed by [3H]thymidine uptake) was significantly increased by PD123319, and the AT2-R agonist CGP42112A reduced the serum-stimulated increase in cell numbers by 23%. Treatment with an AT1-R antagonist, TCV116, for 20 weeks inhibited progression of interstitial fibrosis by 28%, whereas with 44-week PD123319 treatment but not 20-week treatment, the extent of the fibrous region was increased significantly, by 29%.

CONCLUSIONS

These findings demonstrate that AT2-R is re-expressed by cardiac fibroblasts present in fibrous regions in failing CM hearts and that the increased AT2-R exerts an anti-AT1-R action on the progression of interstitial fibrosis during cardiac remodeling by inhibiting both fibrillar collagen metabolism and growth of cardiac fibroblasts.

[Usefulness of magnetic resonance imaging for managing patients with prosthetic carbon valve in the mitral position]

The safety, findings and clinical usefulness of magnetic resonance (MR) imaging were assessed in patients with a prosthetic carbon valve in the mitral position. In vitro deflection, heating and image distortion due to the magnetic field of a 1.5 tesla MR machine were examined in three carbon valves (CarboMedics, St. Jude Medical and Björk-Shiley valves). In vivo MR imaging of the left ventricular horizontal long-axis, vertical long-axis and short-axis views was performed by electrocardiographically synchronized spin echo and field (gradient) echo techniques in eight patients with prosthetic mitral carbon valves, consisting of six CarboMedics valves, one St. Jude Medical valve and one Björk-Shiley valve. No deflection and significant heating was seen in all three valves in vitro. Although little image distortion was shown in the CarboMedics and St. Jude Medical valves, a small distortion toward the frequency encoded direction was seen in the Björk-Shiley valve but caused no difficulty in assessing the surrounding images. Four of the eight patients had normal sinus rhythm and the other four had atrial fibrillation. The prosthetic valves were depicted as signal voids in the images taken by both spin echo and field echo techniques in vivo. Clear structural information with little image distortion of the adjacent tissues of the prosthetic valves were obtained in all patients, although the image of the Björk-Shiley valve which contained stainless steel in the frame had a slightly stronger distortion than those of the CarboMedics and St. Jude Medical valves which contained titanium. The stainless wire suture material used to close the sternal incision was depicted as a signal void, and the areas of the signal loss were larger in the images taken by the field echo technique than those by the spin echo technique. The images taken by the spin echo technique in patients with atrial fibrillation had reduced quality due to the irregularity of repetition time. Cine MR imaging by the field echo technique showed physiological mitral regurgitant jets as signal loss within the flowing blood, which appeared as high signal intensity, bidirectionally in the bileaflet mechanical valve and unidirectionally in the monoleaflet mechanical valve. An abnormal cavity was seen behind the basal left ventricular myocardium in one patient with a CarboMedics valve. The wall of the abnormal cavity was disrupted abruptly and the rest of the wall consisted of pericardium and adjacent tissue in the image taken by the spin echo technique. The image taken by the field echo technique showed an abnormal jet flow from the basal part of the left ventricular cavity into the abnormal cavity, which was compatible with left ventricular pseudoaneurysm. Two-dimensional echocardiography and Doppler color flow mapping disclosed the abnormal cavity and the abnormal flow inside, but failed to show the connection between the left ventricle and the cavity due to reverberation of the ultrasound signal by the prosthetic valve. These findings suggest that MR imaging is a safe and promising method to assess the complications and valvular function in patients with a prosthetic carbon valve in the mitral position.

Increased nitric oxide production and inducible nitric oxide synthase activity in colonic mucosa of patients with active ulcerative colitis and Crohn's disease

It is postulated that an enhanced production of nitric oxide by inflamed intestine plays a role in the pathophysiology of active inflammatory bowel disease. In this study, systemic NOx concentrations and colonic nitric oxide synthase activity were determined in patients with ulcerative colitis or Crohn's disease. The relationship between these two parameters and disease activity, as well as differences in nitric oxide synthase activity between ulcerative colitis and Crohn's disease, were areas of specific focus. Patients with active ulcerative colitis and Crohn's disease had significantly elevated plasma NOx concentrations; a positive correlation was found between NOx values and inducible nitric oxide synthase activities in the active mucosa of these patients. In active ulcerative colitis, levels of inducible nitric oxide synthase were significantly elevated in both normal and inflamed mucosa, although inducible nitric oxide synthase activity was higher in the latter. These colonic inducible nitric oxide synthase activities correlated well with the results of endoscopic and histologic grading of inflammation. There was no increase in constitutive nitric oxide synthase activity in patients with active ulcerative colitis. However, constitutive nitric oxide synthase activity was significantly increased in the inflamed mucosa in patients with Crohn's disease. In Crohn's disease, elevated inducible nitric oxide synthase activity was found in both normal and inflamed mucosa, with no significant difference between the tissues. Such differences in nitric oxide production in the colonic mucosa possibly reflect the significant differences in the pathophysiology and characteristic clinical features between ulcerative colitis and Crohn's disease.

Amelioration of chronic inflammation by ingestion of elemental diet in a rat model of granulomatous enteritis

The beneficial effect of elemental diet (ED) in the treatment of Crohn's disease is reported, although the exact mechanism for this remains to be elucidated. In this study the effects of ED on intestinal inflammation were investigated in a rat model of granulomatous enteritis. Intestinal inflammation was induced by a single intramural injection of peptidoglycan-polysaccharide (PG-PS) from group A streptococci into rat ileal Peyer's patches. A single injection of PG-PS in combination with fibrinogen, which retains PG-PS at the injection site, induced severe granulomatous inflammation associated with mucosal ulceration. Immunohistochemical study and immunocytochemical analysis of the cell suspension from Peyer's patches showed accumulation of macrophages and an increase in interleukin-2 receptor (IL-2R)-positive T cells after PG-PS treatment. Chemiluminescence (ChL) activity and nitrite and nitrate (NOx) levels in the mesenteric venous blood as well as Ca(2+)-independent (inducible) nitric oxide synthase (NOS) activity in Peyer's patches were increased by PG-PS treatment. In rats fed with ED, both macroscopic and histologic damage scores were significantly decreased as compared with those in rats fed with the control diet. ED inhibited the increase in the numbers of macrophages and IL-2R-positive T cells in Peyer's patches. Increased ChL activity, NOx levels, and Ca(2+)-independent NOS activity were also reduced significantly by feeding with ED. These data suggest that ED reduces progression of PG-PS-induced chronic intestinal inflammation by modulating activation of T cells, production of nitric oxide, and generation of oxygen free radicals.

Down-regulation by cAMP of angiotensin II type 2 receptor gene expression in PC12 cells

The rat angiotensin II type 2 receptor (AT2-R) gene was isolated, and cis-regulatory regions in its 5'-flanking area were analyzed. Primer extension and RNase protection analyses revealed a single transcriptional initiation site at the position 24 bp downstream of the TATA box. The 5'-flanking region of AT2-R contained several cis-regulatory elements, such as AP-1, AP-2, C/EBP, NF-1, NF-IL6, NF-kappa B, and glucocorticoid- and cAMP-responsive elements (CRE). The treatment of PC12 cells with dibutyryl cAMP caused a marked decrease (90%) in the AT2-R mRNA level, which was blocked by the inhibitor of protein kinase A and did not require new protein synthesis. The protein level was also reduced 84% after a 24-h exposure to cAMP and the binding affinity was unchanged. The half-life of the AT2-R mRNA decreased -66% by cAMP as compared with control (18.4 +/- 0.4 h). Deletion and mutation analyses of the 5'-flanking region (1.2 Kb) revealed that there were one negative (-1,199 to -739) and two positive cis-regulatory regions (-739 to -436 and -59 to +45), and that the CRE motif located at -426 repressed (-23%) the promoter activity of the rat AT2-R gene. The region between -59 and +45 containing TATA box and AP-2 site accounted for 70% of the promoter activity. These findings indicate that the promoter activity of the rat AT2-R gene is modulated by several cis-regulatory regions and that cAMP markedly downregulates the expression of the AT2-R mainly by inducing AT2-R mRNA destabilization rather than CRE-mediated inhibition of the gene transcription. Thus, humoral factors that transduce cAMP as an intracellular signal may modulate AT2-R-mediated function of Ang II by reducing AT2-R expression.

Mechanical stretch induces enhanced expression of angiotensin II receptor subtypes in neonatal rat cardiac myocytes

Mechanical stress plays a pivotal role in the development of cardiac hypertrophy during hemodynamic overload, and angiotensin (Ang) II secreted from stretched myocytes plays an important role in mechanical stretch-induced hypertrophy. In the present study, we examined stretch-induced expression of Ang II receptors in an in vitro stretch model using 1-day-old rat myocytes. Both Ang II type 1 receptor (AT1-R) and type 2 receptor (AT2-R) mRNA levels were upregulated by myocyte stretching with similar time courses: significant increases were evident 6 hours after stretching, maximal levels (2.8- and 3.3-fold, respectively) were observed at 12 hours, and these were sustained for up to 18 hours. Ang II receptor expression in fibroblast-rich cultures was not affected by stretching. Conditioned medium in which myocytes were stretched for 12 hours significantly downregulated AT1-R and AT2-R mRNA levels in recipient myocytes, and this effect was almost completely blocked by AT1-R antagonists but not AT2-R antagonists. Stretch-induced expression of AT1-R and AT2-R mRNAs was further increased by 27% and 31%, respectively, after pretreatment with AT1-R antagonists, suggesting that Ang II secreted from stretched myocytes downregulates both AT1-R and AT2-R. Western blot and binding assays showed that the number of AT1-Rs and AT2-Rs increased by 2.4- and 2.6-fold, respectively, without affecting receptor affinities. Inositol phosphate response to 0.5 mumol/L Ang II was enhanced 2.1-fold in stretched myocytes. Nuclear runoff assays and treatment with actinomycin D revealed that stretch-induced upregulation of AT1-R was mainly due to increased transcription, whereas that of AT2-R resulted from a stabilizing effect on AT2-R mRNA metabolism. Stretch-induced changes in levels of Ang II receptors were inhibited by genistein but not by H-7, staurosporin, and protein kinase C depletion or by BAPTA-AM. Exposure to cycloheximide did not affect stretch-induced changes. These findings indicate that nonsecretory pathways activated by myocyte stretching upregulate the expression of Ang II receptor subtypes transcriptionally and posttranscriptionally through mechanisms involving stretch-activated tyrosine kinases independently of de novo protein synthesis and that the AT1-R-mediated action of Ang II is functionally enhanced in stretched cardiac myocytes.

[Three-dimensional reconstructed magnetic resonance imaging for diagnosing persistent left superior vena cava: comparison with magnetic resonance angiography and plain chest radiography]

The usefulness of low-cost, three-dimensional (3D) images reconstructed from magnetic resonance (MR) imaging for investigating persistent left superior vena cava was assessed and compared to the diagnostic accuracy of chest radiography. MR imaging by the spin-echo technique and MR angiography were performed in 10 patients with this anomaly diagnosed previously by contrast echocardiography and radionuclide angiocardiography. Four patients had complicating cardiac anomalies, one with postoperative atrial septal defect, one with postoperative ventricular septal defect, one with atrial septal defect and partial anomalous pulmonary venous return, and one with aortic coarctation and patent ductus arteriosus. Multisectional and multiphasic MR images were used for the 3D-reconstruction of the cardiovascular and mediastinal structures with a NeXT workstation and a 3D-kit. The 3D-reconstructed MR imaging clearly showed the persistent left superior vena cava and the anatomical relationship with the other cardiovascular and mediastinal structures in all 10 patients. Vascular shadows were observed outside the upper left border of the aortic arch on the chest radiographs in seven patients, and the 3D-reconstructed MR images revealed these shadows to be compatible with superior caval vein. The ratios of the diameter between the left and right superior venae cavae with and without the left innominate vein were 0.63 +/- 0.14 (mean +/- SD) and 0.94 +/- 0.08, respectively. Three-dimensional reconstructed MR imaging is a useful method for recognizing persistent left superior vena cava and precise examination of the chest radiographs often allowed detection of the vascular shadows caused by this anomaly.

[Gadolinium-diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging of dilated cardiomyopathy: clinical significance of abnormally high signal intensity of left ventricular myocardium]

This study investigated the clinical significance of abnormally high signal intensity in the left ventricular myocardium on gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced magnetic resonance (MR) imaging in patients with dilated cardiomyopathy. Gd-DTPA enhanced MR imaging, Tl-201 myocardial single photon emission computed tomography (SPECT), Tc-99m radionuclide angiocardiography, M-mode echocardiography, electrocardiography and chest radiography were performed in 18 patients with dilated cardiomyopathy. The left ventricle was divided into five areas, the anteroseptal, anterolateral, inferoseptal, posterolateral and apical areas. Five patients (group A) had 0-2 and 13 patients (group B) had 3-5 high signal intensity areas. High signal intensity areas were demonstrated in 19 of 90 areas (21%) before Gd-DTPA enhancement and 50 of 90 areas (56%) after enhancement. Fifteen of 34 areas (44%) with abnormal Tl-201 uptake showed high signal intensity before Gd-DTPA enhancement and 31 (91%) showed high signal intensity after enhancement. Fifteen areas without abnormal Tl-201 uptake also showed high signal intensity after enhancement. Left ventricular ejection fraction (LVEF) and percent fractional shortening (%FS) in group B were lower than those in group A. LVEF(r = 0.78) and %FS (r = 0.82) were significantly correlated with the number of high signal intensity areas. Systolic left ventricular dimension was larger in group B than that in group A, and a significant correlation (r = 0.62) between systolic left ventricular dimension and the number of high signal intensity areas was found. There was no significant difference in right ventricular ejection fraction, left ventricular peak filling rate, diastolic left ventricular dimension, left ventricular thickness, cardiothoracic ratio or SV1+RV5 or 6 between group A and B. There was no correlation of peak filling rate, diastolic left ventricular dimension, cardiothoracic ratio or SV1+RV5 or 6 with the number of high signal intensity areas. These results suggest that abnormal high signal intensity on Gd-DTPA enhanced MR imaging may reflect myocardial degeneration, necrosis or fibrosis, and the high signal intensity predicts the severity of left ventricular dysfunction in dilated cardiomyopathy.

Regulation of angiotensin II type 2 receptor gene by the protein kinase C-calcium pathway

In the present study, rat angiotensin II type 2 (AT2) receptor expression was upregulated in confluence-arrested PC12 cells compared with expression in proliferating cells. Treatment with cycloheximide inhibited the increase in mRNA levels in confluent cells. The state of growth arrest by serum deprivation was associated with increased expression of the AT2 receptor, which was markedly suppressed by exposure to the active phorbol ester 12-O-tetradecanoylphorbol 13-acetate and the calcium ionophore A23187. Similar inhibitions were also observed in myocytes isolated from neonatal rat heart. The change in AT2 mRNA levels by serum deprivation was due to the increase in the gene transcription rate. The effect of 12-O-tetradecanoylphorbol 13-acetate was mediated through decreases in gene transcription and mRNA stability, whereas A23187 affected mRNA stability. Vasoactive substances with the protein kinase C-calcium pathway, such as norepinephrine and angiotensin II, also downregulated the AT2 mRNA level in myocytes. These findings indicate that the expression of AT2 receptor in PC12 cells is regulated in a growth state-dependent manner, which is involved in confluence-induced new protein synthesis, thus providing a means by which cells can modulate their responsiveness to external angiotensin II stimulus. The activation of protein kinase C or calcium mobilization modifies this regulatory mechanism, suggesting that neurotransmitters or vasoactive substances with the protein kinase C-calcium pathway at least in part affect neuronal activity or blood pressure control by downregulating AT2 receptor expression.

[Clinical significance of abnormal high signal intensity of left ventricular myocardium by gadolinium-diethylenetriaminepenta-acetic acid enhanced magnetic resonance imaging in hypertrophic cardiomyopathy]

The significance of abnormal high signal intensity observed in left ventricular myocardium by gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) enhanced magnetic resonance (MR) imaging in hypertrophic cardiomyopathy (HCM) patients was assessed by comparison with T1-weighted MR imaging, thallium-201 (201Tl) myocardial scintigraphy, radionuclide angiocardiography, M-mode echocardiography, electrocardiography, and chest radiography. The 16 patients were divided into three groups: 8 patients (group I) with abnormal high signal intensity before and after Gd-DTPA enhancement, 4 (group II) with abnormal high signal intensity only after enhancement and 4 (group III) without abnormal high signal intensity. Thallium-201 myocardial single photon emission computed tomography (SPECT) showed 4 of the 8 patients in group I, 3 of the 4 patients in group II and only 1 of the 4 patients in group III had abnormalities of regional 201Tl uptake in the left ventricular myocardium. No significant difference in left ventricular ejection fraction (LVEF) was seen between groups I, II, and III (64 +/- 13%, 67 +/- 17% and 71 +/- 7%, respectively) although three patients of group I had LVEF of less than 55%. Left ventricular peak filling rates (PFR) of groups I and II were significantly lower than that of group III (1.90 +/- 0.44, 2.41 +/- 0.43 and 3.37 +/- 0.48 EDV/sec, respectively). Group I had larger end-diastolic left ventricular dimension (LVDd), significantly larger end-systolic left ventricular dimension (LVDs), and smaller % fractional shortening (%FS) than group III (49 +/- 4 vs 42 +/- 6 mm, 31 +/- 5 vs 22 +/- 4 mm, and 38 +/- 8 vs 49 +/- 4%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid HPLC assay with coulometric detection for norepinephrine and 3-methoxy-4-hydroxyphenylglycol in the mouse brain

For the rapid assay of norepinephrine (NE) and its major metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG) in the mouse brain, we developed a simple method using isocratic HPLC with coulometric detection. This method permits NE and MHPG assay within 5 min in one chromatographic run. Within-run coefficients of variation for NE and MHPG in the working standard solution were 0.8% and 0.6% (n = 50), respectively. The detector responses were linear from 0.025 to 100 pmol for NE and from 0.05 to 100 pmol for MHPG in the working standard solution. Using this method, the NE and MHPG concentrations were measured in discrete brain areas of the mouse prior treatment with or without alpha-methyl-p-tyrosine or N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4).

Prolonged survival in a patient with a single ventricle without pulmonary stenosis

Prolonged survival of the patient with a single ventricle is rare. We report the case of a 57-year-old man who has type A3 of Van Praagh's classification of single ventricle with pulmonary hypertension without pulmonary stenosis. Favorable streaming, a large bulboventricular foramen, and intact atrioventricular valves may have contributed to his long-term survival.

Alteration of mucosal immunity after long-term ingestion of an elemental diet in rats

The effects of an elemental diet on lymphocyte transport in intestinal lymph and immune responses of gut-associated lymphoid tissue were investigated in rats. The control animals were fed a conventional diet. After 4 week of feeding, the total calorie intake and body weight gain showed no differences between the two groups. The number and total area of Peyer's patches and the ratio of height of villi to height of crypt showed no significant differences between the two groups. The rate of lymph flow in intestinal lymphatics showed no significant change in treated animals compared with the control rats. However, an elemental diet induced a significant decrease in lymphocyte flux in intestinal lymphatics compared with that in control rats. Lymphocyte subsets in intestinal lymph revealed a significant decrease in CD3-positive cells, especially CD4-positive cells in the elemental diet-treated group. A significant decrease in the number of immunoglobulin A-containing cells and a decreased CD4/CD8 ratio in T-cell subsets were observed in the lamina propria of ileal mucosa in the elemental diet-treated group by morphometric analysis in the immunohistochemical study. Specific antibody-secreting cells in intestinal lymph were also investigated after rats were intraduodenally primed with cholera toxin and challenged with the same toxin after an interval of 2 weeks. No significant difference was seen between the two groups in any of the numbers of anti-cholera toxin immunoglobulin-secreting cells in any immunoglobulin A, immunoglobulin G, or immunoglobulin M class as determined by the enzyme-linked immunospot assay.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo effect of chronic administration of vasoactive intestinal peptide on gut-associated lymphoid tissues in rats

The in vivo effects of chronic administration of vasoactive intestinal peptides (VIP) on the lymphoid cell traffic and the population and function of cells in intestinal lymph and gut-associated lymphoid tissues were examined in rats. VIP was continuously infused from the superior mesenteric artery in rats at a dose of 10 ng/min/kg body weight for 96 h. Lymphocyte transport through intestinal lymph was significantly reduced by VIP without any changes in lymph flow. When lymphocyte subpopulation was examined in intestinal lymph, T cell subsets were decreased with a dominant reduction in the population of helper T cells. T cell subsets were also decreased in mesenteric lymph nodes, but in this case suppressor/cytotoxic T cell subsets were mainly reduced. Despite of the decrease in lymphocyte transport through intestinal lymph and changes of lymphocyte subpopulation, proliferative response of lymphocytes from intestinal lymph and mesenteric lymph nodes to phytohemagglutinin did not show any significant alteration after administration of VIP. By histochemical study on the lamina propria of the small intestine, the population of pan T cells, especially helper T cells, was demonstrated to be significantly decreased after VIP treatment. There was also a marked decrease in the number of immunoglobulin (Ig) A-containing cells in the lamina propria of the small intestine in VIP-treated rats, while no significant changes were seen in the number of IgG and IgM-containing cells. Our present results showed the possibility that a long-term alteration of serum VIP levels could affect the dynamics of immune effector cells and IgA production in gut-associated lymphoid tissues.

Right ventricular ejection fraction during exercise in patients with recent myocardial infarction: effect of the interventricular septum

To investigate the effect of interventricular septum (IVS) on right ventricular function during exercise, radionuclide angiocardiography was performed in 50 patients with recent myocardial infarction. Twenty-five patients had involvement of IVS according to thallium uptake in IVS (group I), and 25 patients were free of IVS involvement (group II). Although there was no statistical difference between the two groups in right ventricular ejection fraction (EF) at rest (45% +/- 10% vs 48% +/- 8%), patients in group I had significantly lower left ventricular (LV) EF (40% +/- 11% vs 53% +/- 11%, p < 0.01) and larger LV end-diastolic volume (129 +/- 46 vs 106 +/- 31 ml, p < 0.05) than those in group II. All parameters increased significantly during exercise in both groups, but patients in group I had significantly lower exercise right ventricular EF (50% +/- 10% vs 56% +/- 9%, p < 0.05), LVEF (44% +/- 11% vs 56% +/- 13%, p < 0.01), and larger LV end-diastolic volume (155 +/- 44 vs 129 +/- 37 ml, p < 0.05) than those of group II. Significant correlations were observed between right ventricular EF and LV end-diastolic volume at rest and during exercise (r = -0.48, p < 0.05, and r = -0.68, p < 0.01, respectively) in group I, but right ventricular EF correlated with LVEF only at peak exercise (r = 0.65, p < 0.01). In contrast, right ventricular EF did not correlate with any variables at rest or during exercise in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of fatty acid absorption on bidirectional release of immunoglobulin A into intestinal lumen and intestinal lymph in rats

Effects of absorption of long and middle chain fatty acids on IgA secretion into the intestinal lumen and intestinal lymph and the factors which evoke changes in IgA secretion during the absorptive process were examined in rat small intestine. Bidirectional secretion of IgA from the intestinal mucosa into the intestinal lumen and intestinal lymph was continuously observed in the control condition. Perfusion of oleic acid (a long-chain fatty acid) micelle into the jejunal loop induced a significant increase in IgA output into the intestinal lymph. In contrast, lymphatic output of IgA was significantly decreased when oleic acid micelle was administered intraduodenally. Absorption of octanoic acid, a middle-chain fatty acid, did not produce any significant changes in IgA output into either direction. CR1505, a CCK-receptor antagonist, significantly attenuated the oleic acid-induced increase in IgA secretion into the intestinal lumen, but did not affect the oleic acid-induced decrease in lymphatic IgA secretion. Pluronic L-81, an inhibitor of chylomicron formation and secretion, significantly attenuated the decrease in IgA output into the intestinal lymph during oleic acid absorption without affecting the luminal IgA output. The rate of release of IgA into the intestinal lumen is stimulated by absorption of long-chain fatty acids possibly through the influence of locally released CCK, while the transport process of IgA into lymphatics is controlled by a different mechanism which is closely correlated with the intracellular formation and secretion of chylomicron.

[Gadolinium-DTPA magnetic resonance imaging in the diagnosis of left atrial myxoma in the elderly]

A 85-year-old woman consulted our hospital with general fatigue, palpitation and chest discomfort changing with different postures. Her electrocardiogram showed sinus tachycardia, atrial premature beats and left atrial overload. 53% cardiothoracic ratio, slightly protruding third arch of the cardiac silhouette and dilated pulmonary artery were seen on the chest X-ray. Two dimensional echocardiography revealed a mass in the left atrium although the quality of echocardiography was suboptimal due to her thoracic deformity. There was no uptake of T1-201 or Ga-67 by the mass. The four-chamber view of Tc-99m ECG-gated SPECT radionuclide angiocardiography showed a filling defect in the left atrium. The T1 weighted magnetic resonance imaging revealed a left atrial mass with relatively low signal intensity. After intravenous injection of Gadolinium-DTPA the signal intensity of the mass increased significantly and the contrast of the mass was improved. The size of the mass was 4 x 4 x 3 cm with a stalk connecting to the interatrial septum. These findings were compatible with left atrial myxoma. Gadolinium-DTPA magnetic resonance imaging is useful in diagnosing left atrial myxoma because it provides information on the size, anatomical location, relationship with other cardiovascular structures and even the characteristics of the mass.

Successful surgical management of thoracic aortic aneurysm in a right-sided aortic arch

A 24-year-old woman with a multilocular sacciform aneurysm in a right-sided aortic arch was successfully treated by aneurysmorrhaphy. Although the cause of the aneurysm could be attributed to congenital factors, its growth was considered to be related to the features of the right-sided aortic arch; strong haemodynamic forces were caused by sharp curving of the aorta which started from an unusually high position and subsequently had a decreased radius.

Natural history of left ventricular function in patients with uncomplicated acute myocardial infarction

To investigate the serial changes of the infarcted and the noninfarcted areas, first-pass radionuclide angiocardiography was performed in 16 patients with uncomplicated anterior myocardial infarction (MI) at four weeks, one year, and two years after the onset of MI. Global ejection fraction (EF) and regional EF of the infarcted area improved significantly from four weeks to one year after MI (from 39 +/- 16 to 44 +/- 16 percent, 23 +/- 3 to 29 +/- 5 percent, both p < 0.01), but did not change from one year to two years after MI. Regional EF of the noninfarcted area and left ventricular end-diastolic and end-systolic volume did not change during the study period. There was a significant relation in the direction of the changes of global EF and regional EF of the infarcted area during the first year after MI, whereas no relation was observed between the changes of global EF and regional EF of the noninfarcted area. A greater improvement in regional EF of the infarcted area was observed in seven patients who had spontaneous recanalization compared with nine patients with totally occluded coronary arteries. Thus, a significant improvement in cardiac function, mainly due to the increase in regional EF of the infarcted area, was observed during the first year after MI, which was related to patency of coronary artery.

Primary embryonal carcinoma of the retroperitoneum

A 32-year-old man with primary embryonal carcinoma of the retroperitoneum, a very rare condition, is reported. The disease took an acute course with rapid enlargement of cervical and inguinal lymph nodes, and high serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) values were observed. His testes were, however, intact. Remarkable tumor regression was achieved by systemic combination chemotherapy with cisplatin, vinblastine, and bleomycin (PVB therapy). This chemotherapy is beneficial even in advanced cases. In the two years since therapy, no recurrence has been observed.

[Total arch replacement for dissecting aneurysm using permanent bypass to the supra-aortic branches and left-heart bypass]

The patient was a 36-year-old women with Marfan syndrome who had received graft replacement of ascending aorta for Stanford-type A dissecting aneurysm two years ago. She was re-operated on for residual arch and descending aortic dissection. We have found that it was Simple and effective to perform total arch replacement by using permanent bypass to the three principal supra-aortic branches and left-heart bypass.

Increased proliferative response of lymphocytes from intestinal lymph during long chain fatty acid absorption

The effect of long chain and medium chain fatty acid absorption on transport and mitogen-induced blast transformation of lymphocytes in intestinal lymphatics was investigated. Intestinal lymph was collected from mesenteric lymph duct cannulated rats maintained in Bollman's cage. Following the intraduodenal administration of oleic acid (long chain fatty acid) or octanoic acid (medium chain fatty acid), only oleic acid produced a significant increase in lymphocyte flux and enhanced proliferative response of lymphocyte in intestinal lymph, without significant alteration of lymphocyte subsets. These changes appeared to be closely correlated with the appearance of radiolabelled oleic acid. Absorption of a medium chain fatty acid, octanoic acid, most of which appeared to be transported to portal blood, did not produce a significant elevation of lymphocyte flux or increased proliferative response of lymphocyte in intestinal lymph. Pluronic L-81, which is a potent inhibitor of the intracellular formation and secretion of chylomicron, significantly attenuated the increased lymphocyte flux and suppressed the enhancement of lymphocyte responsiveness to PHA in intestinal lymph after stimulation by oleic acid administration. There is a possibility that lymphocyte transport and proliferative response in intestinal lymph during oleic acid absorption are closely related to the process of chylomicron formation and secretion to lymphatics in the intestinal mucosa.

Pharmacological properties of ceruletide in the vertical and horizontal locomotor activities of mice

To clarify the pharmacological properties of ceruletide (CER) and cholecystokinin-octapeptide (CCK-8) with respect to vertical (VLA) and horizontal (HLA) locomotor activities of mice, effects of pretreatment with CER (0.5, 5, and 50 micrograms/kg, IP) and CCK-8 (5, 50, and 500 micrograms/kg, IP) on apomorphine (0.1 mg/kg, SC)- and clonidine (0.1 mg/kg, SC)-induced hypo-VLA and -HLA and on apomorphine (1 mg/kg, SC)-induced hyper-VLA and -HLA were examined. CER and CCK-8 had a dose-dependent inhibitory effect on VLA and HLA in intact mice. Pretreatment with CER had a biphasic effect (increase and decrease) on apomorphine- and clonidine-induced hypo-VLA, as well as an effect on apomorphine-induced hypo-HLA, a decreased effect on clonidine-induced hypo-HLA, and a decreased effect on apomorphine-induced hyper-VLA and -HLA. On the other hand, pretreatment with CCK-8 had no effect on apomorphine- and clonidine-induced hypo-VLA and -HLA and a decreased effect on apomorphine-induced hyper-HLA but not on hyper-VLA. These results suggest that for apomorphine- and clonidine-induced locomotion in mice CER has pharmacological properties different from those of CCK-8.

[Radionuclide assessment of left ventricular diastolic function in patients with mitral stenosis before and after percutaneous transvenous mitral commissurotomy; use of list mode method in patients with atrial fibrillation]

To evaluate the effect of percutaneous transvenous mitral commissurotomy (PTMC), equilibrium radionuclide angiocardiography was performed in eight patients with mitral stenosis who had atrial fibrillation. Accurate cardiac function in patients with atrial fibrillation is difficult to assess, since the wide fluctuation of cardiac cycle makes the ventricular hemodynamics variable. A new processing algorithm was devised to make multiple gated images discriminated from a heart rate distribution histogram. We obtained about 1,000 beats data by list mode acquisition, and processed a heart rate distribution histogram. The data in the area +/- 5% of the most frequent heart rate were converted into frame mode and a representative time activity curve was derived. Mitral valve area calculated by echocardiography increased from 1.3 +/- 0.5 to 2.0 +/- 0.6 (cm2) significantly (p less than 0.01). The mean transmitral pressure gradient measured by catheterization decreased from 12.4 +/- 5.9 to 4.9 +/- 3.7 (mmHg) significantly (p less than 0.01) and the clinical symptoms improved in all patients. The change in left ventricular ejection fraction from 43 +/- 9 to 48 +/- 13 (%) was not statistically significant, but peak filling rate (PFR) derived from the time activity curve increased from 1.5 +/- 0.3 to 2.0 +/- 0.4 (EDV/sec) significantly (p less than 0.01). Thus PFR is a noninvasive parameter that can evaluate the effect of PTMC.

Adverse reactions to lipiodol ultra fluid: report of an accidental case

A 25-year-old Japanese woman experienced pulmonary edema, shock, encephalopathy and silent pancreatitis after hysterosalpingography using lipiodol ultra fluid, because the contrast media flowed directly into the blood stream from endometrium injured by several curettages for termination of pregnancy. Total iodine concentrations in plasma and urine decreased exponentially and their half-life was 16.12 and 13.04 days, respectively. Clear correlations were observed between the iodine concentration in plasma and the amelioration of both electroencephalogram and neuropsychic abnormalities. Adverse reactions of oil-soluble contrast media are also discussed.