Sources of Ca2+ in relation to generation of acetylcholine-induced endothelium-dependent hyperpolarization in rat mesenteric artery

1. The aim of the present study was to identify the sources of Ca²⁺ contributing to acetylcholine (ACh)-induced release of endothelium-derived hyperpolarizing factor (EDHF) from endothelial cells of rat mesenteric artery and to assess the pathway involved. The changes in membrane potentials of smooth muscles by ACh measured with the microelectrode technique were evaluated as a marker for EDHF release.
2. ACh elicited membrane hyperpolarization of smooth muscle cells in an endothelium-dependent manner. The hyperpolarizing response was not affected by treatment with 10 μM indomethacin, 300 μM N^G-nitro-L-arginine or 10 μM oxyhaemoglobin, thereby indicating that the hyperpolarization is not mediated by prostanoids or nitric oxide but is presumably by EDHF.
3. In the presence of extracellular Ca²⁺, 1 μM ACh generated a hyperpolarization composed of the transient and sustained components. By contrast, in Ca²⁺-free medium, ACh produced only transient hyperpolarization.
4. Pretreatment with 100 nM thapsigargin and 3 μM cyclopiazonic acid, endoplasmic reticulum Ca²⁺-ATPase inhibitors, completely abolished ACh-induced hyperpolarization. Pretreatment with 20 mM caffeine also markedly attenuated ACh-induced hyperpolarization. However, the overall pattern and peak amplitude of hyperpolarization were unaffected by pretreatment with 1 μM ryanodine.
5. In the presence of 5 mM Ni²⁺ or 3 mM Mn²⁺, the hyperpolarizing response to ACh was transient, and the sustained component of hyperpolarization was not observed. On the other hand, 1 μM nifedipine had no effect on ACh-induced hyperpolarization.
6. ACh-induced hyperpolarization was nearly completely eliminated by 500 nM U-73122 or 200 μM 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, inhibitors of phospholipase C, but was unchanged by 500 nM U-73343, an inactive form of U-73122. Pretreatment with 20 nM staurosporine, an inhibitor of protein kinase C, did not modify ACh-induced hyperpolarization.
7. These results indicate that the ACh-induced release of EDHF from endothelial cells of rat mesenteric artery is possibly initiated by Ca²⁺ release from inositol 1,4,5-trisphosphate (IP₃)-sensitive Ca²⁺ pool as a consequence of stimulation of phospholipid hydrolysis due to phospholipase C activation, and maintained by Ca²⁺ influx via a Ni²⁺- and Mn²⁺-sensitive pathway distinct from L-type Ca²⁺ channels. The Ca²⁺-influx mechanism seems to be activated following IP₃-induced depletion of the pool.

     

Propofol combined with epidural anesthesia for a patient complicated with myelodysplastic syndrome (MDS)

A 55 year-old-female with myelodysplastic syndrome (MDS) underwent hemi-colectomy. We planned to avoid the use of nitrous oxide, because of its myelo suppressive effects. Therefore, we maintained the anesthesia with propofol combined with epidural anesthesia. After the surgical operation, the patient developed no hematological complications.     

Metastatic seeding of bile duct carcinoma in the transhepatic catheter tract: Report of a case

We describe herein the case of a 51-year-old woman in whom metastatic tumor seeding of the percutaneous transhepatic biliary drainage tract occurred following a pancreatoduodenectomy for carcinoma of the distal common bile, duct. An abdominal computed tomography scan done 6 months after the initial operation detected a hepatic lesion located at the site of the previous percutaneous transhepatic biliary drainage tract. Implantation of bile duct carcinoma in the drainage tract was diagnosed, and the recurrent tumor was successfully resected by performing a subsegmentectomy of segment 3 and removal of the adjacent abdominal wall. At present, 5 years and 4 months after the second resection, the patient is in good health without any signs of recurrence. This case report demonstrates that an aggressive surgical approach should be performed for tumor seeding of a transhepatic biliary catheter tract.     

Pulmonary small cell carcinoma associated with sarcoid reactions: Report of a case

A 45-year-old male was admitted to our hospital for investigation of a nodular shadow in segment 5 of the right lung on a chest computed tomogram. A right middle lobectomy with mediastinal lymph node dissection was performed under a diagnosis of lung cancer, and histologic examination confirmed small cell carcinoma. There were sarcoid reactions in the resected lymph nodes and the lung parenchyma, but no signs of systemic sarcoidosis were evident. Sarcoid reactions are rarely observed in the regional lymph nodes draining malignant tumors. Moreover, while they are most common in squamous cell carcinoma of the lung, they extremely rare in small cell carcinoma. To our knowledge, this is only the third report of this unusual entity in the English and Japanese literature.     

Functional regulation by dopamine receptors of serotonin release from the rat hippocampus: in vivo microdialysis study

The functional regulation by dopamine (DA) receptors of serotonin (5-HT) release from the rat hippocampus was investigated by use of in vivo microdialysis. Dialysate 5-HT levels were reduced by co-perfusion of 10 M tetrodotoxin (TTX) and were elicited by K⁺ (60 and 120 mM) stimulation in a concentration-dependent manner. Local perfusion (10 M) and peripheral administration (20 mg/kg, i.p.) of fluoxetine produced increases in 5-HT levels. These results indicate that the spontaneous 5-HT levels in the rat hippocampus can be used as indices of neuronal origin from the serotonergic nerve terminals. The nonselective dopamine (DA) receptor agonist apomorphine (1, 10 and 100 M), when perfused through the probe over a period of 40 min, increased 5-HT release in a concentration-dependent manner. Apomorphine-induced (100 M) increases in 5-HT release was abolished by pretreatment with the selective D₂ receptor antagonist, S(–)-sulphide (1 and 10 M), but not prevented by pretreatment with the selective D₁ receptor antagonist, R(+)-SCH-23390 (R(+)-7-chloro-8-hydroxy-3-methyl-l-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine) (1 M). S(–)-Sulpiride and R(+)-SCH-23390 by themselves did not alter the spontaneous 5-HT levels. The 5-HT release was elevated by perfusion of the selective DA reuptake inhibitor GBR 12909 (1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-[3-phenylpropyl]piperazine)(1, 10 and 100 M), indicating the possibility of not only exogenous but also endogenous DA-mediated facilitatory effects on 5-HT release in vivo. The 5-HT release was also elevated by perfused (±)-PPHT ((±)-2-(N-phenylethyl-N-propyl)-amino-5-hydroxytetralin)(1, 10 and 100 M), the selective D₂ receptor agonist, in a concentration-dependent manner. On the other hand, (±)-PPHT (100 M) failed to increase 5-HT release in catecholamine (CA)-lesioned rats pretreated with 6-hydroxydopamine (6-OHDA)(200 g/rat, i.c.v.). The (±)-PPHT-induced (100 M) increase in 5-HT release was prevented not only by pretreatment with 10 M S(–)-sulphide but also by pretreatment with the ₂-adrenoceptor antagonist idazoxan (10 M). These findings suggest that the functional regulation of 5-HT release via D₂ receptors exists in the rat hippocampus. Furthermore our results indicate that the facilitatory effect of 5-HT release via D₂ receptors may be mediated indirectly by noradrenergic neurons, but not mediated directly through D₂ receptors located on serotonergic nerve terminals.     

Pterion and epipteric bones in Japanese adults and fetuses, with special reference to their formation and variations]

The formation and variations of the pterion and epipteric bones were examined in total of 614 Japanese skulls. The materials used consisted of 258 skulls of Japanese fetuses ranging from the fourth to the ninth month, 20 skulls of Japanese juveniles from the third month to 17 years of age, and 336 skulls of Japanese adults from 20 to 89 years of age. For the skulls examined the incidence of ossification in the fetal sphenoidal fontanelle was 3.6% on each side, whereas epipteric bones were observed in more than 10% of the juvenile and adult pteria. Great variation was seen in the form of the adult pterion. The most common form was a sphenoparietal contact in which the pteria were classified into usual (306 pteria), high (119), low (21), and narrow (32) types Another form of this type, a frontal process of the temporal bone without contact with frontal bone, was found in five pteria. The form of frontotemporal contact is classified into two types: One is with a frontal process of the temporal bone (17 pteria), and another is a K-shaped contact referred to as "stellate" (four). The two types were observable in adult skulls of all ages, although the fused pteria and fusing epipteric bones were most often seen in cases over 40 years of age. The results suggest that the pterion formation has two phases, the first occurring before the occlusion of sphenoidal fontanelle, and the second starting after 40 years of age.     

Behavioral and pharmacological studies of juvenile stroke-prone spontaneously hypertensive rats as an animal model of attention-deficit/hyperactivity disorder]

The present study was undertaken to evaluate juvenile stroke-prone spontaneously hypertensive rats (SHRSP) as an animal model of attention-deficit/hyperactivity disorder (AD/HD). Juvenile SHRSP showed significant increases in horizontal ambulatory activity and vertical rearing activity in the open field as compared with genetic control Wistar-Kyoto rats (WKY). Anxiety-related behavior assessed by elevated plus-maze as an index of impulsivity, the entries into open arms and the spent time in the open arms of SHRSP were significantly higher than those of WKY. Spontaneous alternation behavior requiring attention and working memory in the Y-maze was significantly impaired in male, but not female, SHRSP when compared with sex-matched WKY. Hippocampal long-term potentiation formation, a cellular model of learning and memory, was not impaired in SHRSP. Methylphenidate, a first choice psychostimulant for AD/HD, significantly alleviated the hyperactivity in SHRSP. However, intense impulsivity of SHRSP was not improved by methylphenidate. Methylphenidate dose-dependently and significantly ameliorated the impaired spontaneous alteration behavior in male SHRSP. These results suggest that juvenile male SHRSP manifest problematic behavior resembling ADHD, namely inattention, hyperactivity and impulsivity. Methylphenidate alleviates the behavioral symptoms of hyperactivity and inattention. Thus, juvenile male SHRSP might be a useful behavioral animal model of AD/HD, from behavioral and pharmacological perspectives.     

Cerebellar hemorrhage after coil embolization for a ruptured vertebral dissecting aneurysm

BACKGROUND: We present a case of ruptured vertebral dissecting aneurysm that exhibited cerebellar hemorrhage after successful embolization of the vertebral artery including the dissected site. CASE PRESENTATION: A 59-year-old man suffered a sudden onset of severe occipital headache when he looked up. Computed tomography demonstrated subarachnoid hemorrhage. Angiography revealed a right vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery. Endovascular embolization of the aneurysm was performed with preservation of the posterior inferior cerebellar artery. The next day, the patient suffered a cerebellar hemorrhage in the vermis. The intracranial pressure was controlled by external ventricular drainage. The patient was discharged with mild cerebellar ataxia and bilateral abducens nerve palsy. CONCLUSION: In a case of vertebral dissecting aneurysm distal to the posterior inferior cerebellar artery, blood circulation in the vertebral arterial system may change after embolization of the aneurysm. In our case, the preserved posterior inferior cerebellar artery might have been hemodynamically stressed postoperatively, resulting in cerebellar hemorrhage. Therefore, strict control of blood pressure is essential in the acute stage after occlusion of the aneurysm.     

Primary Endodermal Sinus Tumor of the Vulva: A Case Report and Review of the Literature

Background.Extragonadal endodermal sinus tumors arising in the external genitalia represent an exceedingly rare malignancy in women. Six cases of endodermal sinus tumors of the vulva have been reported to date, with three cases failing to respond to conservative surgery and vincristine-based chemotherapy. We report a seventh case of vulvar endodermal sinus tumor that was treated with radical surgery and platinum-based chemotherapy.Case.RT is an 18-year-old female who presented with a vulvar mass that was diagnosed as endodermal sinus tumor at the time of biopsy. She was subsequently treated with modified radical vulvectomy and ipsilateral groin lymphadenectomy, followed by bleomycin, etoposide, and cisplatin chemotherapeutic regimen. She has since remained free of disease for 18 months as evidenced by serum α-fetoprotein and physical exam at 18 months.Conclusions.Vulvar endodermal sinus tumors represent a very small number of germ cell tumors in women. Based on the previous accounts, this disease appears to be more fatal than endodermal sinus tumor arising at other sites. These tumors also have a predilection for local metastasis. Due to the previous accounts, we chose to treat this patient with radical surgery and platinum-based chemotherapy. This treatment regimen has resulted in a disease-free state for 18 months.     

The change in tenascin expression in mouse uterus during early pregnancy

Purpose: Our aim was to examine the changes in spatiotemporal tenascin (TN) expression in mouse uterus during early pregnancy, when the uterine tissue undergoes a tremendous restructuring. Methods: Using immunohistochemistry and in situ hybridization, the changes in distribution of TN protein in mouse uterine tissues in pregnancy Day 0 through Day 5 were analyzed. Results: Immunoreactive TN and TN mRNA were expressed in the basement membrane of the epithelium as well as in the smooth muscle layer, and their distribution shifted from the subbasement region on Day 0–3 to the smooth muscle layer on Days 4 and 5. Conclusions: These results indicate that TN expression in the uterus during early pregnancy is spatiotemporally different and may be regulated by a different mechanism.