Adrenal and circulating renin-angiotensin system in stroke-prone hypertensive rats.

The plasma and adrenal renin-angiotensin system in stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto (WKY) rats were examined in animals at 5, 11, 18, and 25 weeks of age. Plasma active renin was significantly increased in 18- and 25-week-old SHRSP with impaired renal function, whereas there was no difference in the plasma prorenin level or renal renin content between the two strains at all ages examined. Thus, the rate of activation of prorenin seems to be enhanced in the kidney of SHRSP with malignant hypertension. Adrenal renin contents were severalfold higher in SHRSP than WKY rats at all ages. However, adrenal angiotensin peptides were not increased in SHRSP aged 5 and 11 weeks. In 18-week-old SHRSP, adrenal angiotensin II (Ang II) and III (Ang III) levels were fourfold and 1.8-fold higher, respectively, than in WKY rats, accompanied by 1.5-fold higher plasma aldosterone. Increased adrenal angiotensin and plasma aldosterone were also found in 25-week-old SHRSP. Zonal distribution studies indicated that the elevated Ang II and III in SHRSP were derived mainly from the capsular tissue (the zona glomerulosa). To examine the contribution of circulating angiotensin to the adrenal angiotensin content, effects of bilateral nephrectomy on adrenal angiotensin and renin were examined in 18-week-old rats. At 24 hours after nephrectomy, plasma angiotensin, prorenin, and active renin were decreased to almost negligible concentrations. Conversely, in both adrenal capsular and decapsular tissues of SHRSP and WKY rats, neither angiotensin nor renin was significantly decreased after nephrectomy. These results suggest that the increase in adrenal capsular Ang II contents in SHRSP may be partly due to an enhanced local production of Ang II.     

Role of endothelium-derived hyperpolarizing factor in ACE inhibitor-induced renal vasodilation in vivo

Although the angiotensin-converting enzyme (ACE) inhibitor-induced bradykinin enhances nitric oxide (NO) release, bradykinin may also stimulate the production of an additional vasodilator, endothelium-derived hyperpolarizing factor (EDHF). This study examined the role of EDHF in mediating the NO-independent action of ACE inhibitors in canine renal microcirculation in vivo. We used intravital CCD camera videomicroscopy that allowed direct visualization of renal microcirculation in superficial and juxtamedullary nephrons in an in vivo, in situ, and relatively intact setting. In the presence of E4177 (an angiotensin receptor blocker), cilazaprilat (30 microg/kg) had no effect on diameter of superficial afferent arterioles (Aff), but it increased renal contents of bradykinin and nitrate plus nitrite, and it elicited dilation of juxtamedullary Aff (from 24.0+/-0.2 to 28.2+/-0.8 microm), juxtamedullary efferent arterioles (Eff) (from 24.2+/-0.2 to 28.0+/-0.8 microm), and superficial Eff (from 18.2+/-0.2 to 19.7+/-0.2 microm). These changes in diameters were prevented by N(alpha)-adamantaneacetyl-d-Arg-[Hyp(3),Thi(5,8),D-Phe(7)]bradykinin, a bradykinin receptor antagonist. The pretreatment with nitro-l-arginine methylester (l-NAME) plus E4177 eliminated the dilator response of juxtamedullary/superficial Eff and the increase in renal nitrate plus nitrite levels induced by cilazaprilat. In contrast, in the presence of E4177+l-NAME, cilazaprilat still caused 8%+/-3% dilation of juxtamedullary Aff, which was completely eliminated by proadifen, a cytochrome-P450 and K(Ca) channel blocker. Collectively, the ACE inhibitor exerts multiple vasodilator mechanisms, including the inhibition of angiotensin II formation; blockade of angiotensin II activity appears to be a dominant mechanism in superficial Aff, whereas the bradykinin-induced NO acts on superficial Eff and juxtamedullary Aff/Eff. Furthermore, a putative EDHF is an additional mechanism for the ACE inhibitor-induced vasodilation of juxtamedullary Aff in vivo.     

A patient undergoing pancreaticoduodenectomy in whom involved common hepatic artery anomalously arising from the superior mesenteric artery was removed and reconstructed

Identifying anatomical variations of the celio-mesenteric arterial branches is important when performing pancreaticoduodenectomy. A relatively rare variation is the common hepatic artery entirely originated as a branch of the superior mesenteric artery. This type of variation is termed hepatomesenteric trunk type common hepatic artery, in which an accessory left hepatic artery arising from the celiac trunk is absent. Preservation of hepatomesenteric trunk type common hepatic artery is indispensable during pancreaticoduodenectomy because fatal hepatic injury or leak of hepaticojejunostomy can occur. The present case report shows a patient with pancreatic head tumor in whom hepatomesenteric trunk type common hepatic artery was involved by the tumor. The patient underwent pancreaticoduodenectomy during which the involved hepatomesenteric type common hepatic artery was removed and reconstructed using saphenous venous grafts. Histopathological examination showed double cancers which were composed of an advanced ductal adenocarcinoma of the pancreas and early bile duct adenocarcinoma. The patient is alive 18 months after the surgery without recurrence.     

Coronary stent implantation in patients with a single coronary artery--a report of 3 cases

An isolated single coronary artery is a rare congenital anomaly and a cause of cardiac ischemia, congestive heart failure, and sudden cardiac death. Reported here are 3 cases of single coronary artery with acute myocardial infarction in which coronary stenting was performed. Also reported are the coronary blood flow patterns of the right coronary artery arising from the single left coronary artery.     

Differential roles of hypothalamic serotonin receptor subtypes in the regulation of prolactin secretion in the turkey hen

In the turkey, exogenous serotonin (5-hydroxytryptamine, 5-HT) increases prolactin (PRL) secretion by acting through the dopaminergic (DAergic) system. In the present study, infusion of the 5-HT_2C receptor agonist, (R)(−)-DOI hydrochloride (DOI), into the third ventricle stimulates PRL secretion, whereas the 5-HT_1A receptor agonist, (+/−)-8-OH-DPAT hydrobromide (DPAT), inhibits PRL secretion. Using the immediate-early gene, c-fos, as an indicator of neuronal activity, in situ hybridization histochemistry showed preferential c-fos co-localization within tyrosine hydroxylase immunoreactive neurons (the rate limiting enzyme in DA synthesis) in the areas of the nucleus preopticus medialis (POM) and the nucleus premammillaris (PMM), in response to DPAT and DOI, respectively. To clarify the involvement of 5-HT_1A and 5-HT_2C receptors in PRL regulation, their mRNA expression was determined on hypothalamic tissue sections from birds in different reproductive stages. A significant difference in 5-HT_1A receptor was observed, with the POM of hypoprolactinemic short day and photorefractory birds showing the highest expression. 5-HT_2C receptors mRNA did not change during the reproductive cycle. The data presented support the notion that DA neurons in the PMM and POM mediate the stimulatory and inhibitory effects of 5-HT, respectively, on PRL secretion and the 5-HTergic system can both stimulate and inhibit PRL secretion.     

A Case of Intestinal Obstruction Caused by Prominent Kyphosis Resulting in Compression of the Intestine by the Costal Arch

An 85-year-old woman with no history of abdominal surgery complained of abdominal pain and vomiting and was referred to us with a diagnosis of intestinal obstruction a few days later. Upon admission to our facility, she presented with marked abdominal swelling and prominent kyphosis. Because of the kyphosis, most of the dilated bowel was compressing her thoracic cavity. No obvious strangulation or free air was observed via abdominal computed tomography imaging. We attempted decompression using a nasogastric tube, but the symptoms persisted. Surgery was performed 2 days after admission. The origin of the obstruction was a compression of the ileocecal region by the costal arch. The bowel was discolored, and thus surgically excised. There were no major postsurgical complications other than a mild wound infection. Until now, there have been no reports of advanced kyphosis inducing ileus, but there are concerns of an increase in similar cases as society continues to age.