Masayuki Kishida

Involvement of activin/BMP system in development of human pituitary gonadotropinomas and nonfunctioning adenomas

Roles of activin/bone morphogenetic protein (BMP) system in the pathogenesis of human pituitary adenoma remain unknown although these factors stimulate follicle-stimulating hormone (FSH) secretion in the normal pituitary. Here we demonstrated that type-I and -II subunit mRNAs of activin/BMP receptors are expressed in Pit-1-negative FSH-producing (FSH-oma) and nonfunctioning pituitary adenomas (NF-oma). Basal levels of serum FSH standardized by luteinizing hormone (LH) were markedly high in FSH-omas in contrast to NF-omas. However, gonadotropin-releasing hormone (GnRH)-induced increment of FSH standardized by that of LH was not changed in FSH-omas, suggesting that imbalanced FSH secretion by FSH-oma is not attributable to GnRH regardless of the expression of GnRH receptor. Although activin betaA subunit was detected in neither adenoma, the betaB subunit was expressed highly in FSH-omas and, to lesser extent, in NF-omas. As for BMPs, BMP-6 and -7 were detected in NF-omas while BMP-4 and -15 were not detected in either type of adenoma. In the presence of pituitary activin/BMP system, the levels of co-expressing follistatin mRNA in the tumors were reduced in FSH-oma compared with NF-oma, suggesting that endogenous follistatin is involved in FSH overproduction through inhibition of activin/BMP system independently of GnRH.

The role of nitric oxide and the renin-angiotensin system in salt-restricted Dahl rats

To elucidate the role of nitric oxide (NO) and renin-angiotensin system (RAS) in the development of salt-sensitive hypertension, we investigated the pressor responses and renal histologic changes after long-term inhibition of endogenous NO synthesis in Dahl-Iwai salt-sensitive (DS) and salt-resistant (DR) rats under salt-re-stricted conditions that exaggerate RAS activation. Male DS and DR rats (6 weeks old) were fed with a low-salt (0.3%) diet for 5 weeks. NG-nitro-L-arginine (L-NA; dissolved in 60 mg/L deionized water), an arginine analogue acting as a NO-inhibitor, was also administered for 5 weeks. L-NA administration induced a gradual increase in systolic blood pressure (SBP) in both strains, and the pressor response in DS rats was apparently more enhanced relative to that in DR rats. Urinary nitrate plus nitrite (u-NOx) excretion was decreased by L-NA, with a significant negative correlation between SBP and u-NOx excretion in DS rats but not in DR rats. Plasma renin activity and urinary aldosterone level were significantly increased in L-NA-treated DS rats on week 5. Marked histologic changes with glomerular sclerosis and increased proteinuria and urinary N-acetyl-beta-glucosaminidase excretion were found in L-NA-treated DS rats but not DR rats. Competitive RT-PCR of mRNA extracted from the glomeruli revealed that angiotensin II type 1 receptor (AT1R) mRNA level was significantly lower in DS rats than in DR rats at week 2, and that L-NA administration significantly reduced glomerular AT1R level of DS rats at week 5, possibly because of downregulation. Our results showed that, even under sodium restriction, the pressor response and renal injury induced by chronic NO inhibition were markedly more enhanced in DS rats than in DR rats, which indicates that depletion of NO participates in both the development of hypertension and glomerular injury in DS rats through a potential activation of RAS irrespective of sodium loading. These data suggest that endogenous NO is an essential determinant of salt-sensitive hypertension in DS rats.

Percutaneous Radiofrequency Ablation for Treatment of Hepatocellular Carcinoma in the Caudate Lobe

OBJECTIVE This study aimed to evaluate the efficacy and safety of percutaneous radiofrequency ablation (RFA) for the treatment of hepatocellular carcinoma (HCC) in the caudate lobe, where RFA is considered to be difficult. MATERIALS AND METHODS Of a total of 810 patients treated by ultrasound-guided radiotherapy between July 2002 and May 2010, medical records of 50 consecutive patients with HCC in the caudate lobe were reviewed in this retrospective study. Twenty-two tumors were found to be in the paracaval portion and 28 in the Spiegel lobe. We retrospectively reviewed the procedures, treatment effect, and complications. RESULTS For all paracaval tumors and eight Spiegel lobe tumors, we used the intercostal approach, and for the remaining Spiegel tumors (n = 20) we used the pass-the-left approach. We found that all tumors were successfully treated, and the local recurrence rate after 2 years was 12%. Cases of mortality or major complications after RFA were absent. CONCLUSION RFA appears to be an effective treatment modality for HCC in the caudate lobe.

Radiofrequency Ablation for the Treatment of Hepatocellular Carcinoma with Decompensated Cirrhosis

Background: Radiofrequency ablation (RFA) is used to treat early-stage hepatocellular carcinoma (HCC), but is sometimes avoided in patients with decompensated liver cirrhosis because of the possible side effect of deterioration of liver function. Aims: In this study, we report the safety and effects of RFA for treating HCC patients with Child-Pugh B/C liver cirrhosis. Methods: Sixty-six consecutive HCC patients with Child-Pugh B/C cirrhosis, who were treated by RFA, were enrolled in this study. We analyzed patient outcomes, the complications of RFA, and changes in liver function and tumor markers. Results: Fifty-six patients were classified as Child-Pugh class B, and 10 were classified as class C. The overall survival rates in patients with Child-Pugh B and C cirrhosis were 82 and 83% at 1 year and 47 and 31% at 3 years, respectively. Serum total bilirubin (T.Bil), albumin, prothrombin time, ascites, and encephalopathy were unchanged at 1, 3, and 6 months after RFA in patients with Child-Pugh B cirrhosis; however, serum T.Bil levels increased significantly at 6 months after RFA in 6/10 (60%) patients with Child-Pugh C cirrhosis. Hemothorax and rupture of esophageal varices were observed in 2 patients; however, there were no complications related to poor liver function. Conclusion: RFA is a useful modality for treating HCC in patients with poor liver function such as Child-Pugh B and C, but careful monitoring after RFA must be needed.

Differential effect of chronic inhibition of calcium channel and angiotensin II type 1-receptor on aldosterone synthesis in spontaneously hypertensive rats.

We have investigated the in vivo effect of chronic blockade of Ca(2+)-channels and angiotensin II type 1 (AT(1))-receptors on aldosterone (Aldo)-synthesis in the adrenal glands of spontaneously hypertensive rats (SHR). Male SHR were administered Ca(2+)-antagonist, amlodipine (10 mg/kg per day) or AT(1)-receptor-antagonist, TCV-116 (1 mg/kg per day) from 7 until 11 weeks of age. Systolic blood pressure (SBP) and heart rate (HR) were significantly higher in SHR than Wistar-Kyoto (WKY) rats. Both treatments resulted in equivalent and significant reduction in SBP in SHR. Aldo-secretion in SHR, which was significantly higher than in WKY rats, was profoundly suppressed by TCV-116 compared with amlodipine. Both treatments resulted in thickening of the zona glomerulosa, which immunohistochemically contains Aldo, at the end of therapy. Competitive reverse transcription-polymerase chain reaction (RT-PCR) showed that CYP11A (P450scc) mRNA regulating the first step of Aldo-synthesis was significantly reduced from week 9 of age by amlodipine, and that CYP11B2 (P450aldo) mRNA regulating the last step of Aldo-synthesis was potently suppressed from 9 weeks of age by TCV-116. Our results indicate that chronic treatment with different antihypertensive agents directly modulates adrenocortical aldosterone synthesis in SHR in vivo via different mechanisms.

Percutaneous Radiofrequency Ablation for Intermediate-Stage Hepatocellular Carcinoma

Objectives: Radiofrequency ablation plays a key role in the treatment of early-stage hepatocellular carcinoma. However, it is not recommended for intermediate-stage hepatocellular carcinoma. The objective of this study was to clarify the efficacy and safety of radiofrequency ablation for treating intermediate-stage hepatocellular carcinoma. Methods: We examined the outcome of 65 consecutive patients who were treated with radiofrequency ablation with or without transarterial chemoembolization for intermediate-stage hepatocellular carcinoma. Results: With a median follow-up of 37 months, overall survival rates of 65 cases at 1, 3, 5, and 7 years were 90, 70, 51, and 36%, respectively. Multivariate analysis of clinical parameters revealed that the multicentric occurrence (MC)/intrahepatic metastasis (IM) was the only significant prognostic factor for overall survival (hazard ratio, 4.9; 95% confidence intervals, 2.1-11.4). Tumor size and tumor number were not significant factors for survival. The overall survival rates of patients with MC (n = 33) at 1, 3, 5, and 7 years were 97, 90, 80, and 59%, respectively; those for patients with IM (n = 32) were 86, 55, 14, and 8%, respectively (p < 0.0001). Two cases (4.9%) had complications of hemothorax and diaphragmatic burn; however, no major complications were observed. Conclusion: Radiofrequency ablation is safe and effective for the treatment of intermediate-stage hepatocellular carcinoma, especially for patients with MC.

Relationship between adrenomedullin and vasopressin-aquaporin system under general anesthesia.

Aim: The roles of adrenomedullin (AM) in body fluid balance under general anesthesia were investigated. Methods: Time course changes in plasma osmolality, AM, arginine vasopressin (AVP), and urinary aquaporin 2 (AQP2) in 17 patients undergoing abdominal surgery under general anesthesia were examined. Results: Increases in plasma AM levels were observed in parallel with increases in the levels of urinary AQP2/creatinine (Cr) before induction and 90 and 180 min after initiation of anesthesia. Significant correlations between plasma AM and urinary AQP2/Cr (r = 0.62, p < 0.0001) as well as urinary AVP/Cr and AQP2/Cr (r = 0.60, p < 0.0001) were uncovered. Multivariate stepwise analysis identified plasma AM as the critical independent factor affecting urinary AQP2/Cr level. Conclusion: A novel correlation of AM and AQP2 which overlays an AVP-AQP2 system may play a key role in fluid homeostasis during general anesthesia.

Chronic treatment with amlodipine modulates adrenocortical angiotensin II receptors in spontaneously hypertensive rats.

We investigated the effects of long-term treatment with calcium-antagonist, amlodipine, on angiotensin II receptors in the adrenal cortex of spontaneously hypertensive rats (SHR). Seven-week-old male SHR were treated with oral amlodipine (10 mg/kg/day) or vehicle (saline) for four weeks. Age-matched normotensive Wistar-Kyoto (WKY) rats were treated with the vehicle similar to control SHR. Systolic blood pressure (SBP) showed time-dependent increase in SHR but not in WKY rats, while amlodipine treatment significantly reduced the high SBP in SHR. Plasma renin activity was serially increased in SHR, which was further enhanced by amlodipine treatment. But the plasma aldosterone level which was increased in SHR was not changed by amlodipine. Competitive reverse transcriptase-polymerase chain reaction showed that the level of adrenocortical angiotensin II type 1 receptor (AT1R) mRNA progressively decreased in vehicle-treated SHR compared to WKY rats and that 4-week course of amlodipine treatment significantly increased AT1R mRNA in SHR to levels comparable to those in WKY rats. Amlodipine treatment reduced the level of adrenocortical angiotensin II type 2 receptor (AT2R) mRNA in SHR from 8 weeks of age. Thus, chronic amlodipine treatment differently modulates both adrenocortical AT1R and AT2R in SHR in a possibly direct manner.

Hypothyroidism associated with anti-human chorionic gonadotropin antibodies secondarily produced by gonadotropin therapy in a case of idiopathic hypothalamic hypogonadism

We report a 22-yr-old male patient with idiopathic hypothalamic hypogonadism who showed secondary resistance to gonadotropin (Gn) therapy over 3 yr after successful treatment with hCG combined with human menopausal Gn. The patient simultaneously developed subclinical hypothyroidism. Endocrine examination revealed low levels of testosterone (0.3 ng/ml), free T4 (0.91 ng/dl), and increased levels of TSH (31.1 μU/ml) in the serum. Serum autoantibodies to thyroid gland were all negative. Interestingly, thyroid function was improved after discontinuation of Gn therapy. In vitro assays by immunoprecipitation using 125I-hCG or 125I-TSH elucidated the presence of anti-hCG antibody in the serum 13 months after commencement of Gn therapy but anti-TSH antibody was not detected in the serum. Furthermore, the anti-hCG antibody specifically bound to hCG but not to other glycoproteins including TSH and FSH based on a competitive displacement assay. Bioassays using porcine thyroid cells revealed that the serum γ-globulin fraction enables the suppression of cyclic AMP (cAMP) synthesis stimulated by TSH. Our findings suggest that anti-hCG and/or anti-idiotypic hCG antibodies induced by hCG therapy impaired TSH-dependent cAMP production through interfering with binding of TSH to its receptor, and this resulted in subclinical hypothyroidism in this patient.

Differential glomerular response to continuous infusion of vasopressin in spontaneously hypertensive rats and Wistar–Kyoto rats

To determine the difference of glomerular response to exogenous vasopressin (VP) in vivo between normotensive and hypertensive rats, we examined the effects of 14-day continuous infusion of VP (1.0 ng/kg/min) on the physiological and histological aspects in 7-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. VP infusion did not result in significant changes in systolic blood pressure, heart rate, serum electrolytes, serum creatinine, urinary protein and N-acetyl-beta-glucosaminidase levels in both strains of rats. VP infusion significantly reduced daily urine volume associated with significant concentration of the urine in WKY rats but not SHR. Kidney and heart weights did not differ significantly after VP infusion between both strains. Glomerular mesangial expansion was significantly enhanced in VP infused SHR, but glomerular cellularity was not different between both strains following treatment. Competitive reverse transcription-polymerase chain reaction revealed that the level of glomerular transforming growth factor (TGF)-beta1 mRNA was significantly higher in SHR than WKY rats, and that this difference was significantly augmented after VP infusion in SHR. VP infusion, however, did not change the level of glomerular mRNAs of platelet-derived growth factor (PDGF) B-chain in both strains. Then, exogenous VP infusion contributes to the glomerular mesangial expansion in SHR, which involved overexpression of glomerular TGF-beta1 without any pressor effect. In contrast, the significant changes of glomerular expansion and TGF-beta1 level were not shown in WKY rats. These findings suggest that the glomerular response to the exogenous VP is preferentially enhanced in SHR.