Role of activation of PIP5Kgamma661 by AP-2 complex in synaptic vesicle endocytosis

Synaptic vesicles (SVs) are retrieved by clathrin-mediated endocytosis at the nerve terminals. Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] drives this event by recruiting the components of the endocytic machinery. However, the molecular mechanisms that result in local generation of PI(4,5)P2 remain unclear. We demonstrate here that AP-2 complex directly interacts with phosphatidylinositol 4-phosphate 5-kinase gamma661 (PIP5Kgamma661), the major PI(4,5)P2-producing enzyme in the brain. The beta2 subunit of AP-2 was found to bind to the C-terminal tail of PIP5Kgamma661 and cause PIP5Kgamma661 activation. The interaction is regulated by PIP5Kgamma661 dephosphorylation, which is triggered by depolarization in mouse hippocampal neurons. Finally, overexpression of the PIP5Kgamma661 C-terminal region in hippocampal neurons suppresses depolarization-dependent SV endocytosis. These findings provide evidence for the molecular mechanism through which PIP5Kgamma661 locally generates PI(4,5)P2 in hippocampal neurons and suggest a model in which the interaction trigger SV endocytosis.

Changes in respiratory physiological dead space and compliance during non-abdominal, upper abdominal and lower abdominal surgery under general anaesthesia

BACKGROUND AND OBJECTIVE

To evaluate the temporal changes in respiratory physiological dead space and dynamic compliance of the respiratory system during non-abdominal, upper abdominal and lower abdominal surgery under general anaesthesia with intermittent positive pressure ventilation.

METHODS

Thirty-four adult patients were studied (non-abdominal surgery, n = 8; upper abdominal surgery, n = 13 and lower abdominal surgery in lithotomy position, n = 13). Physiological dead space was measured using the single breath carbon dioxide test. The physiological dead space to tidal volume ratio (VD/VT), dynamic compliance of respiratory system, expiratory tidal volume and respiratory rate were measured 10 min after tracheal intubation, and 30, 60 and 120 min later.

RESULTS

In lower abdominal surgery group, VD/VT was significantly increased at 120 min compared with 0 min (P = 0.005) and 30 min (P = 0.009). There were no significant differences in VD/VT between the three groups at any time point. Compliance decreased significantly in patients with upper abdominal (120 min) and lower abdominal surgery (60 and 120 min), but there were no significant changes during non-abdominal surgery.

CONCLUSIONS

We found that the VD/VT increased in patients undergoing lower abdominal surgery in lithotomy and head down tilt, and compliance decreased in those undergoing upper abdominal and lower abdominal surgery over time.

Clinical manifestations of influenza a myocarditis during the influenza epidemic of winter 1998-1999

OBJECTIVES

The clinical features of myocarditis that developed during the influenza epidemic of winter 1998-1999 were investigated to emphasize the need for medical attention to this disease.

METHODS

Nine patients were treated under diagnoses of acute myocarditis during the winter of 1998-1999. Five (two males and three females, mean age 52 +/- 18 years) were examined with myocarditis associated with influenza A. The diagnosis of influenza A myocarditis was based on electrocardiographic and echocardiographic abnormalities, increased creatine kinase levels and at least a four-fold increase in influenza A virus titers using paired sera.

RESULTS

All patients had preceding flu-like symptoms and fever. Cardiac involvement developed between 4 and 7 days after the onset of influenza symptoms. Dyspnea progressively worsened in three patients, one went into shock and one had persistent fever, cough and mild dyspnea without apparent cardiac symptoms. Three patients had ST elevation associated with Q waves and one had complete left bundle branch block. The creatine kinase levels were abnormally increased and global wall motion of the left ventricle on echocardiography was decreased in all patients. Two patients had diagnoses of fulminant myocarditis. One patient died of pneumonia following cerebral infarction, but the left ventricular dysfunction normalized in the remaining four patients.

CONCLUSIONS

Cardiac involvement occurred between 4 and 7 days after the onset of influenza symptoms, and worsening dyspnea was the most common symptom. Electrocardiography, echocardiography and creatine kinase levels should be checked to determine the potential for cardiac involvement when patients present with suspected influenza associated with worsening dyspnea or prolonged weakness. Increasing the awareness of influenza myocarditis may help in the earlier identification and treatment of this disease during influenza epidemics.

[Recurrent pulmonary embolism from left subclavian thrombosis: a case report]

A 38-year-old woman was admitted to our hospital because of pulmonary thromboembolism. Thrombolysis therapy resulted in initial improvement in symptoms and laboratory data. However, 4 months later, pulmonary thromboembolism recurred despite antiplatelet and anticoagulation therapy. Contrast venography and venous ultrasonography of both upper and lower extremities revealed subtotal occlusion and venous thrombosis of the left subclavian vein with collateral vessels, but no evidence of lower extremity venous thrombosis. She had no history of subclavian venous catheterization, neoplasm, hypercoagulability or other predisposing cause of thrombus formation. Operative ligation of the left subclavian vein was performed at the junction with the internal jugular vein. White thrombus was identified within the venous lumen. She was well without recurrent pulmonary thromboembolism or venous insufficiency for 10 months after the operation. Surgical interruption of the subclavian vein may be effective to prevent recurrent pulmonary thromboembolism in patients with recurrent pulmonary thromboembolism due to venous thrombosis of the upper extremity despite therapeutic anticoagulation.

[One-hour protocol stress myocardial scintigraphy: prospective study of diagnostic accuracy for the detection of coronary artery stenosis]

A one-hour protocol for stress myocardial scintigraphy using technetium-99m-tetrofosmin (Tc-tetrofosmin) was compared with coronary arteriography for the detection of coronary artery stenosis in 90 consecutive patients without prior myocardial infarction, revascularization procedure or vasospastic angina. Tc-tetrofosmin stress myocardial scintigraphy acquired a rest image 20 min after intravenous administration of Tc-tetrofosmin (185 MBq, 1/5 vial) using a three-head gamma camera collecting 20-sec views over 360 degrees. The stress test using bicycle ergometer was performed and administration of Tc-tetrofosmin (740 MBq, 4/5 vial) was repeated at the peak stress point. The stress image was acquired 15 min after the second injection with 5-sec views over 360 degrees. Coronary arteriography revealed the presence of significant coronary artery stenosis (> 75%) in 56 vessels of 45 patients, including 35 patients with single-vessel disease, 5 with two-vessel disease, 2 with three-vessel disease, and 3 with left main trunk disease. The overall sensitivity and specificity for the detection of coronary artery disease by visual analysis were 91.1% and 77.8%, respectively, and by quantitative analyses (using bull's-eye method) were 95.6% and 91.1%, respectively. The individual stenotic vessel sensitivities in the right coronary artery, left anterior descending artery, and left circumflex artery were 84.6%, 90.9%, and 78.6%, respectively. The specificities were 97.3%, 95.9%, and 100.0%, respectively. These results suggest that stress myocardial scintigraphy using the present new protocol is a promising approach for the detection of coronary artery stenosis.

Effect of pacing rate in pacing therapy in hypertrophic obstructive cardiomyopathy

The effects of dual-chamber pacing therapy in patients with hypertrophic obstructive cardiomyopathy (HOCM) have been reported in short- and long-term studies. Almost all of these studies have reported that the key factor in pacing therapy is the setting of the atrioventricular (AV) interval. However, studies focusing on the effects of pacing rate on the hemodynamic state are rare. In this study, cardiac catheterization was performed in 2 patients during temporary pacing at various rates and AV intervals. When the pacing rate was increased slightly (to 70-90/min), AV sequential pacing decreased peak subaortic pressure gradient and increased systolic aortic pressure without increase in pulmonary capillary wedge pressure, left ventricular end-diastolic pressure, and the time constant of isovolumetric relaxation. In another case, of a patient who became refractory to AV sequential pacing therapy at an optimum AV interval, pacing at a slightly higher rate relieved syncope. Thus, AV sequential pacing therapy performed at a slightly higher rate than normal in a patient with HOCM may lead to a decreased subaortic pressure gradient and relief of symptoms without noticeable deterioration in cardiac function.

Rapidly-growing ectopic pituitary adenoma within the sphenoid sinus--case report

A 75-year-old male with left abducens nerve paresis presented with an ectopic pituitary adenoma invading the posterior wall of the sphenoid sinus. The sphenoidal mass grew rapidly for 6 months with left ophthalmoplegia and was partially removed via the transsphenoidal approach. The histological examination showed a benign pituitary adenoma, but the MIB-1 proliferating cell index was 6.8%, reflecting the clinically malignant behavior. The symptom gradually improved without tumor regrowth over 1.5 years after conventional irradiation.

An autopsy case of diffuse malignant mesothelioma of the pericardium

A report is presented of an autopsy case of a 71-year-old Japanese man with a diffuse malignant epithelial mesothelioma of the pericardium with massive pericardial effusion and a thickened pericardium. He had no history of exposure to asbestos. He suffered severe heart failure and later died. Autopsy revealed that the tumor had developed over the pericardium. Microscopically, the tumor cells were arranged in an epithelial form, and histochemically, the cytoplasm of these cells contained glycogen and hyaluronic acid. The tumor tissue showed immunohistochemical positivity for cytokeratin, epithelial membrane antigen, vimentin, cancer antigen 125, thrombomodulin, mesothelial antigen, muscle actin and human milk fat globule. In contrast, all the tumor cells were negative for human carcinoembryonic antigen and epithelial antigen. Ultrastructurally, the tumor cells had long, thin microvilli, abundant intermediate filaments, intracytoplasmic lumina and long desmosomes. It is considered that the patient had a typical malignant epithelial mesothelioma of the pericardium.

Total capsular calcification in a prolactinoma--case report

A 42-year-old male presented with a prolactin-producing pituitary adenoma with an atypical radiological appearance. The tumor was incidentally found by magnetic resonance imaging, which demonstrated a cystic tumor in the enlarged and partially empty sella turcica. Computed tomography revealed the tumor was surrounded by calcification with an egg-shell appearance. The serum prolactin level was 37 ng/ml. The operative finding was a calcified shell-containing cystic tumor. Immunohistochemical staining revealed prolactin-positive cells. The combination of the unusual calcification, and enlarged and partially empty sella was considered to be a sequela of spontaneous degeneration of the tumor.

[A technique for removal of entrapped intra-aortic balloon catheter through the left axillary artery]

A case of intra-aortic balloon pumping (IABP) entrapment in which the ruptured catheter could be removed through the left axillary artery was reported. A 68-year-old man was admitted with persistent chest pain, and because of his poor cardiac condition, an IAB catheter was inserted by the Seldinger technique. During attempted extraction of the IAB catheter resistance was encountered and it turned out to be entrapped. Then a guide-wire was passed through the IAB lumen to the left axillary artery, the artery was exposed, and the tip of the guide-wire and IAB catheter were led to the arteriotomy site. After the balloon was dissected, the IAB catheter could be removed through the axillary artery. Finally, left femoro-left branchial artery bypass was performed with e-PTFE graft because of the arterial injury and ischemia of the involved arm. The patient recovered from this episode.

Illumination of mastoid air cell for suboccipital craniotomy: technical note

The mastoid air cell was illuminated to estimate the location of the sigmoid sinus in 12 cases of a retrosigmoid suboccipital craniotomy for cerebellopontine angle tumors. A special illuminator system was designed, and the tip of the illuminator was placed inside the external auditory canal. The posterior margin of the illuminated air cell was delineated on the outer surface of the skull after the skin flap was turned and the position of the sigmoid sinus was estimated with reference to the preoperative computed tomographic scan. The posterior margin of the mastoid air cell in an axial slice, including the internal auditory canal, usually exists within the breadth of the sigmoid sinus. A gap between the posterior margin of the mastoid air cell and the position of the sigmoid sinus was easily corrected by the computed tomographic finding. This method was found to be simple and reliable in performing the suboccipital craniotomy with safety and exactness.

[The experiences of a large amount of steroid therapy for symptomatic vasospasm after subarachnoid hemorrhage: clinical analysis of 21 cases]

Among 48 cases of subarachnoid hemorrhage, 21 cases (43.8%) showed symptomatic vasospasm. We attempted treatment, using a large amount of steroid therapy for them in accord with our own protocol. In the 21 cases who received steroid therapy for symptomatic vasospasm, 18 cases (85.7%) showed improvement of their symptoms. This was especially evident in about 8 cases where the steroid effect was remarkable. There was a serious side effect, GI--tract bleeding, in one case. Although the effect of the steroid therapy was evident for slight or moderate spasm cases, 5 severe spasm cases responded poorly. We concluded that a large amount of steroid therapy was effective for slight or moderate symptomatic vasospasm cases, and that in severe ones possibly another therapy combined with steroid therapy would be necessary.

[Generalized choreic movement associated with subarachnoid hemorrhage]

A case of generalized choreic movement associated with subarachnoid hemorrhage is reported. A 71 year-old hypertensive woman suddenly developed severe headache 14 days before admission. Consciousness disturbance and involuntary movement involving the face and upper extremities appeared about 8 days after onset. The involuntary motion was diagnosed as generalized choreic movement. CT scans showed subarachnoid hemorrhage with ventricular dilatation and periventricular lucency involving bilateral caudate nuclei. On admission the patient was stuporous with Hunt & Kosnik Grade 4. She showed involuntary choreic movement in both arms, trunk and face; hemiparenis and hyperreflexia were absent. An angiography revealed a right internal carotid-anterior choroidal artery aneurysm with vasospasm. After clipping the aneurysm in the following day, the consciousness disturbance and choreic movement gradually improved. By eight days after operation, the choreic movement completely disappeared. An MRI showed lacunar infarcts in the bilateral basal ganglia, predominantly in the caudate nuclei. In our case, the choreic movement is supposed to have been caused by impaired circulation in the bilateral corpora striata due to vasospasm and hydrocephalus after subarachnoid hemorrhage, in addition to the preexisting lacunar infarcts in the basal ganglia. This is claimed to be the first reported case of generalized choreic movement in associated with subarachnoid hemorrhage, which improved after surgery.

Diurnal change of plasma atrial natriuretic peptide concentrations in patients with congestive heart failure

Diurnal change of plasma atrial natriuretic peptide (ANP) concentration was observed in 14 patients with congestive heart failure (CHF) and in eight healthy control subjects. Blood pressure, heart rate, and plasma concentration of ANP were obtained at intervals of 4 hours beginning immediately after midnight. In the CHF group, plasma ANP concentrations at the time of blood sampling were all higher than those in the control group. Patients with severe CHF had higher plasma ANP concentrations than those in patients with less severe CHF. Plasma ANP concentration in the control group was highest at 4:00 AM and was lowest at 4:00 PM. The percent change of ANP secretion (% delta ANP): [(ANP at 4:00 AM-ANP at 4:00 PM)/ANP at 4:00 PM] x 100%, increased in the control group, while it decreased in the CHF group. Moreover, % delta ANP was much lower in patients with severe CHF than it was in patients with less severe CHF. There was a possible relation between the severity of CHF and the increase of ANP secretion associated with the relative diminution of nocturnal ANP secretion. Thus the present data imply that the diurnal change in ANP was lost in patients with CHF.

[Successful chemotherapy in undescended testicular and extragonadal germ cell tumors: report of 2 cases]

Two patients with advanced germ cell tumor who entered complete remission following intensive combination chemotherapy, radiation therapy and surgical intervention are reported. A 28-year-old businessman presented with abdominal pain and masses associated with an elevated HCG level for which he underwent exploratory laparotomy. Large retroperitoneal masses were found and microscopical examination of the masses were revealed seminoma. Three courses of combination chemotherapy consisting of CDDP, VLB and PEP were given to the patient followed by radiation therapy to the parailiac, paraaortic, mediastinal and supraclavicular lymph nodes with boost irradiation to the paraaortic lymph nodes where the large masses were located. The other patient was a 21-year-old student who developed sharp precordial chest pain which proved to be due to a large mediastinal mass accompanied by an elevated AFP level. He was treated with radiation therapy to the mediastinum, surgical resection and combination chemotherapy. However, he showed recurrence in the lungs associated with rising AFP levels, and was given a salvage chemotherapy consisting of 3 courses of CDDP, ADR, PEP and Etoposide. Both patients were successfully treated with combined modalities of treatment including intensive chemotherapy and have been off therapy without recurrence for over 12 and 4 months, respectively.