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Biomedical subjects

S Akamine

Publications and source records attributed to S Akamine.

At least 19 recordsLinked to original sources
PubMed2002

Circulating nitrite anions are a directly acting vasodilator and are donors for nitric oxide.

Inhaled nitric oxide (NO) is a pulmonary vasodilator, but also acts systemically, causing negative cardiac inotropic effects and a fall in systemic vascular resistance. Circulating metabolites of NO are presumed to be responsible. We questioned the role of nitrite anions and the manner in which they might contribute to these effects. Nitrite and nitrate anions coexist in blood, while circulating levels of dissolved NO are very low. Nitrate anions are not biologically active, but nitrite anions may have a biological role through the release of NO. In vitro, at 37 degrees C and in aerated Krebs bicarbonate solution, the steady-state concentration of dissolved NO was proportional to the concentration of NO in the gas. Nanomolar concentrations of dissolved NO coexisted with micromolar concentrations of nitrite anions. The idea of an equilibrium between the two in solution was also supported by the observed release of NO from nitrite anions in the absence of gas. With rings of precontracted pig pulmonary arteries (prostaglandin F(2alpha); 10 micromol/l), the steady-state concentration of dissolved NO causing 50% relaxation (EC(50)) was 0.84+/-0.25 nmol/l, corresponding to a gaseous concentration of 2.2 p.p.m. The EC(50) of nitrite was 4.5+/-0.7 micromol/l, a concentration normally found in plasma. The estimated concentration of dissolved NO derived from this nitrite was 4.5 pmol/l, some 100 times lower than would be needed to cause relaxation. The rate of exhalation of NO was increased and pulmonary vascular resistance was reduced by the addition of nitrite solution to the perfusate of isolated perfused and ventilated pig lungs, but only when millimolar concentrations were achieved. Thus circulating nitrite anions are a direct vasodilator, only being a carrier of effective amounts of "free" NO at higher than physiological concentrations.

Analog-Digital Conversion↗
PubMed2001

Completion pneumonectomy for recurrent or second primary lung cancer.

OBJECTIVE: We studied 8 patients undergoing completion pneumonectomy for recurrent or second primary lung cancer. METHODS: Subjects were men who averaged 62 years of age. Of these 6 had p-stage I, and 2 p-stage II disease at initial operation. At the second operation, we diagnosed 3 with second primary lung cancer and 5 with recurrent lung cancer. We predicted postoperative pulmonary function by calculating the predicted forced expiratory volume in 1.0 second (FEV1.0) from residual numbers of subsegments after completion pneumonectomy. All predicted FEV1.0 in our 8 cases ranged from 544 to 926 (773 +/- 144) ml/m2. RESULTS: Six patients experienced postoperative complications and morbidity was 75%. One patient undergoing completion sleeve pneumonectomy after radiation therapy for local carina recurrence died on 7th postoperative day due to anastomotic dehiscence and pneumonia. Overall operative mortality was 12.5% (1/8). Four remain alive and actuarial 5-year survival was 37.5%. CONCLUSIONS: Careful consideration is needed in determining operative indications for completion pneumonectomy for patients after radiation therapy. Patients with recurrent squamous cell carcinoma who have p-stage I disease at initial operation and those with second primary lung cancer and p-stage I or II disease can expect relatively a long-term survival, and we concluded that completion pneumonectomy could be conducted in these cases with a satisfactory prognosis.

Adenocarcinoma↗
PubMed2001

The optimal stimulation site for chronic stimulation of the subthalamic nucleus in Parkinson's disease.

To determine the optimal stimulation site within the subthalamic nucleus (STN), monopolar stimulation of four electrode contacts and the resulting effects on parkinsonian symptoms were evaluated in 10 consecutive patients. The UPDRS score for rigidity and akinesia improved significantly after stimulation at each of the contacts, compared to the pre-evaluation state (Fisher's test, p < 0.05). The most significant improvement was obtained after stimulation at contact-2 (rigidity: 74.4 +/- 20.4%, akinesia: 53.7 +/- 14.3%) (Fisher's test, p < 0.001). Contact-2 was located at the dorsal border of the STN at a mean distance of 0.3 +/- 0.7 mm. DBS at the dorsal border of the STN, where the stimulation affects the neurons as well as their axonal fibers, produces the greatest clinical improvement in parkinsonian symptoms.

Brain Mapping↗
PubMed2001

[Results of carinal resection for primary lung cancer].

Carinal resection for primary lung cancer was clinical evaluated. Carinal resection was performed in 18 patients. Thirteen patients underwent carinal resection and the other 5 sleeve or wedge pneumonectomy. The carinal reconstruction was of montage type in 10 patients and the double-barrel type in 2. There were 2 operative deaths, postoperative mortality rate was 11.1%. The 5-year survival for 16 patients excluding the 2 operative deaths was 38.8%. The 5-year survivals were 41.7% and 21.4% for N0 and N2 disease, respectively. Selected patients with localized lesion without mediastinal lymph node metastasis are the candidate for carinal resection and reconstruction.

Adult↗
PubMed2001

[A case of primary racemose hemangioma of bronchial artery with recurrent hemoptysis].

A 42-year old man was admitted to our hospital because of hemoptysis. Bronchial arteriography revealed a tortuous and dilated left bronchial artery with a shunt formation between the bronchial and pulmonary arteries. Bronchial artery embolization using a sponge was performed three times to treat the hemoptysis, but all attempts failed. The patient therefore underwent left lower lobectomy, after which no hemoptysis was observed. Histopathologically, the resected tissue showed no inflammatory change. Interestingly, abnormal vessels resembling arteriovenous malformations were also found. Although the embolization therapy was effective in several reported cases, we concluded that surgery was required for this patient with persistent hemoptysis because of the development of collaterals and a bronchial-pulmonary artery shunt.

Adult↗
PubMed2000

[Prolactinoma in a child showing high MIB-1 labeling index: a case report].

We report a very rare case of a prolactin secreting pituitary tumor (prolactinoma) which occurred in a 12-year-old boy. The tumor showed an extremely high MIB-1 index. The clinical implication in the postoperative management of childhood prolactinoma is discussed. The patient showed right third nerve palsy, and MRI revealed a pituitary tumor invading the right cavernous sinus. Preoperative hormonal evaluation showed a very high prolactin level (2800 ng/ml). The patient underwent transsphenoidal surgery, and the third nerve palsy disappeared just after the procedure. MIB-1 index obtained by using immunostaining was 18.9%. Postoperative prolactin level remained high (2200 ng/ml), and the patient was treated with 10 mg/day of bromocriptine. Prolactinomas in children with high MIB-1 index show resistance to treatment with bromocriptine. In the postoperative management of a childhood prolactinoma, it should be considered how to control sufficiently high serum prolactin level to expect sexual development while preserving other normal residual pituitary functions. If control with bromocriptine, fails radiation treatment should be adopted with careful observation of the increase in height and the progress of sexual development of the patient.

Bromocriptine↗
PubMed1999

Twenty-four-hour preservation in gamma-hydroxybutyrate improves lung function in a canine single-lung allotransplantation.

BACKGROUND: We investigated the effect of gamma-hydroxybutyrate (GHB) when added to the low-potassium University of Wisconsin (LPUW) solution used for the preservation of canine lung for 24 hr. We also examined the effect of pretreatment of donor and recipient dogs with GHB on lung function after transplantation. METHODS: Two groups were investigated. In the LPUW group, donor lungs were flushed with LPUW solution without GHB. In the GHB group, donor and recipient dogs were pretreated with GHB, and donor lungs were flushed with LPUW containing GHB. RESULTS: Posttransplant graft function was best in the GHB group. At 1 hr after reperfusion, PaO2 in the GHB group (475.7+/-96.2 mmHg) was significantly higher than in the LPUW group (188.3+/-102.7 mmHg, P<0.05). Furthermore, the use of GHB resulted in a significant increase in lung compliance (28.3+/-6.5 ml/cm H2O) compared with LPUW group (21.5+/-2.8 ml/cm H2O). CONCLUSIONS: Our results suggest that GHB is potentially useful for functional improvement of hypothermically preserved canine lung allografts after reperfusion.

Adenosine↗
PubMed1999

Extended resection for lung cancer invading mediastinal organs.

We analyzed 49 patients with non-small-cell lung cancer invading mediastinal organs such as the left atrium (15), superior vena cava (13), trachea (11), aorta (5), thoracic vertebral body (4) and esophagus (1). Lung resection included lobectomy (37), pneumonectomy (8) and limited resection (4). Twenty-seven patients underwent carina- or bronchoplasty. Complete resection was possible in 35 patients. Operative mortality was 12% and overall 5-year survival was 13%. Median survival time was 519 days. Factors significantly affecting survival were the completeness of resection, node status, and histological type. Five-year survival was 18% with complete resection and 0% with incomplete resection (p < 0.0001). Five-year survival for patients with squamous cell carcinoma was 36% and for those with other types of lung cancer, 0% (p < 0.02). Five-year survival for patients classified pathologically as N0 or N1 was 36% and, for those classified as N2 or N3, 0% (p < 0.05). We concluded that aggressive resection for lung cancer invading the mediastinal organs involves a high mortality rate, making selectivity important. Patients undergoing complete resection, classified as N0 or N1, and having squamouse cell carcinoma may benefit most from surgery.

Adult↗
PubMed1999

Thymic cystectomy through subxyphoid by video-assisted thoracic surgery.

In this paper we present a new technique for thymic cystectomy by video-assisted thoracic surgery. The thoracoscope was inserted using a Vein Harvest (Ethicon Endo-Surgery Co, Ltd, Cincinnati, OH) through a 5-cm subxyphoid incision. A Harmonic Scalpel (Ethicon Endo-Surgery) and Cherry Dissector (Ethicon Endo-Surgery) were used for dissection. The thymic cyst was successfully removed through the incision without thoracotomy. The advantage of this technique is that it is less invasive than video-assisted thoracic surgery through the thorax, removing the need for a thoracotomy.

Aged↗
PubMed1999

[Endovascular treatment of ruptured intracranial aneurysms using platinum coils in patients over 80 years of age].

Endovascular treatment of intracranial aneurysms using plantinum coils was performed in 10 patients over 80 years of age. The patients ranged in age from 81 to 96 years. Preoperative Hunt and Kosnik grading revealed one patient in grade I, 4 in grade II, 3 in grade III, and 2 in grade IV. The aneurysms were located in the internal carotid artery in 6 patients, in the anterior communicating artery in 1, and in the middle cerebral artery in 3 respectively. Intra-aneurysmal occlusion was accomplished in 8 patients with total or subtotal occlusion in 6 and partial occlusion in 2. In one patient with a peripheral middle cerebral artery aneurysm, the parent artery was occluded just proximal to the aneurysm. In the remaining one patient in grade III, an aneurysm associated with wide neck could not be occluded because of coil protrusion into the parent artery. In 9 patients who were successfully treated, all five patients in grade I or II and one in grade III resulted in good outcome, but the other three patients in grade III and IV showed poor outcome. No evidence of recurrent hemorrhage was noted during the follow-up period ranging from 2 months to 4 years. Endovascular coil embolization is a useful therapeutic alternative for treating ruptured intracranial aneurysms in patients over 80 years of age, especially those in Grade I or II.

Aged↗
PubMed1999

[Endoscopic resection of the thoracic sympathetic trunk for the treatment of frequent syncopal attack of idiopathic long QT syndrome].

A 22 year old man was diagnosed as having Jervell and Lange-Nielsen syndrome (JLNS), which includes a prolonged QTc, congenital neural deafness, and syncopal attacks or sudden death. In spite of medication with beta blocker, syncopal attack increased in frequency since his sister suddenly had died of JLNS. Because left stellate ganglion block improved the QTc dispersion, left cardiac sympathectomy was scheduled under the video-assisted thoracic surgery. After the premedication with midazolam, anesthesia was induced with thiamylal, and maintained with nitrous oxide, sevoflurane, and fentanyl. Serious arrhythmias were not observed throughout the perioperative period. Sympathetic trunk was successfully resected from the top of 1st ganglion to the bottom of 4th ganglion of left thoracic sympathetic trunk. Horner's sign did not appear after the surgery. Although the shortening of QTc was not significant, QTc dispersion during exercise was improved, and syncopal attack was not observed until 6 months after the surgery.

Adult↗
PubMed1998

Minimizing the inhaled dose of NO with breath-by-breath delivery of spikes of concentrated gas.

BACKGROUND: Pulmonary vasodilatation with a 100 ppm concentration of NO given as a short burst of a few milliliters at the beginning of each breath (NOmin) was compared with conventionally inhaled NO, in which a full breath of 40 ppm of NO was inhaled (NOCD). METHODS AND RESULTS: NOmin was studied in 16 patients with severe pulmonary hypertension and in 16 isolated porcine lungs with experimentally induced pulmonary hypertension. We compared volumes of 8 to 38 mL of 100 ppm NO in N2 injected at the beginning of each breath with conventional inhalation of 40 ppm NO in air. NOCD and NOmin were studied in 4 pigs after inhibition of NO synthase with NG-nitro-L-arginine methyl ester (1 to 2 mg/kg IV) had raised the pulmonary vascular resistance index (PVRI) from 4.4+/-0.8 to 10. 0+/-1.6 mm Hg. L-1. min-1. kg-1. A similar comparison was made in 7 isolated porcine lungs after the thromboxane analogue U46619 (10 pmol. L-1. min-1) increased the mean PVRI from 4.6+/-0.8 to 12.2+/-1. 3 mm Hg. L-1. min-1. kg-1. Patients' mean PVRI was reduced from 29. 2+/-3.7 to 24.0+/-3.1 with NOmin and 24.5+/-3.3 mm Hg. L-1. min-1. m-2 (mean+/-SEM) with NOCD. In isolated porcine lungs, there was the same reduction of PVRI for NOmin and NOCD between 12.7% and 34.8%. CONCLUSIONS: A small volume of NO inhaled at the beginning of the breath was equally effective as NOCD but reduced the dose of NO per breath by 40-fold, which ranged from 1.2x10(-8) (0.4 microg) to 1. 6x10(-7) mol/L (4.8 microg) compared with 5.3x10(-7) (16 microg) to 1.2x10(-6) mol/L (36 microg) per breath with NOCD.

Administration, Inhalation↗
PubMed1998

Treatment of pulmonary hypertension with the continuous infusion of a prostacyclin analogue, iloprost.

OBJECTIVE: To compare prostacyclin with an analogue, iloprost, in treatment of severe pulmonary hypertension. PATIENTS: Eight patients with severe pulmonary hypertension: primary in five, thromboembolic pulmonary hypertension in three. METHODS: All patients underwent right heart catheterisation. Mean (SEM) right atrial pressure was 9.9 (2.2) mm Hg, mean pulmonary artery pressure 67.4 (3.0) mm Hg, cardiac index 1.75 (0.13) l/min/m2 and mixed venous oxygen saturation 59.1(3.1)%. Continuous intravenous epoprostenol (prostacyclin, PGI2) or iloprost was given for phase I (three to six weeks); the patients were then crossed over to receive the alternate drug in an equivalent phase II. MAIN OUTCOME MEASURES: Exercise tolerance was measured at baseline and at the end of phase I and II with a 12 minute walk; distance covered, rest period, percentage drop in arterial oxygen saturation (delta Sao2%) and percentage rise in heart rate (delta HR%). RESULTS: Walking distance covered rose from (mean (SEM)) 407.5 (73) to 591 (46) m with PGI2 (p = 0.004) and to 602.5 (60) m while on iloprost (p = 0.008). Rest period decreased from 192 (73) seconds at baseline to 16 (16) seconds with PGI2 (p = 0.01) and to 58 (34) seconds with iloprost (p = 0.008). Delta HR% was 37.5(6)% at baseline, 35(3)% on PGI2, and 24(6)% on iloprost (p = 0.04). CONCLUSIONS: Both intravenous PGI2 and iloprost caused significant improvement in exercise tolerance. Iloprost offers an alternative to PGI2 treatment of severe pulmonary hypertension.

Adult↗
PubMed1998

[Long-term survival in terms of DNA-RNA contents in breast cancer].

Fifty-nine primary breast cancers were analyzed by flow cytometric cellular DNa-RNA contents stained by acridine orange simultaneous DNA-RNA double staining. Forty-three cases (72.9%) out of 59 had abnormal stemlines (DNA aneuploidy), and 16 normal ones (DNA diploidy). RNA indices widely ranged from 1.41 to 9.02 (2.99). There was no correlation between DNA indices and RNA indices. The patients with DNA diploidy had a better prognosis than those with DNA aneuploidy, but the differences were not significant. The patients with a high RNA index of more than 4.0 had a significantly poorer prognosis than those with an index of less than 4.0. Those results suggest that RNA contents, and DNA contents are independent prognostic factors, and especially RNA contents may be a good prognostic factor in long-term survival in breast cancer.

Breast Neoplasms↗
PubMed1998

[Chest wall reconstruction after resection of malignant chest wall tumors].

Full-thickness chest wall resection is performed for complete removal of primary and secondary malignant chest wall tumors. Large defects of the chest wall after resection must be repaired to maintain adequate ventilation, to protect important intrathoracic structures, and to preserve cosmetic integrity. Various materials have been utilized over the years to replace the rigid chest wall. At present, Marlex mesh and a composite of Marlex mesh and methylmethacrylate are frequently used to reconstruct rigid chest wall defects. On the other hand, to replace the soft part of the chest wall and cover the rigid materials, pedicled muscle flaps, myocutaneous flaps, or omentum are used. Major pedicled flaps include the pectoralis major, rectus abdominis and latissimus dorsi muscular, and musculocutaneous flaps. Techniques are now available to repair any chest wall site, and to restore chest continuity in patients whose tumors are curatively resected.

Humans↗