Retinotopic and nonretinotopic field potentials in cat visual cortex

Two types of field potentials were identified in cat visual cortex using contrast reversal of oriented bar gratings: a short-latency fast-local component with a retinotopic organization similar to that seen with single-unit discharges at the same cortical site, and a slow, nonretinotopic component with a longer peak latency. The slow-distributed component had an extensive receptive field mapped by measuring the amplitude of binary kernels and showed strong inhibitory interactions within the receptive field. The peak latency of the slow-local component increased with distance from the retinotopic center, suggesting a possible conduction delay. Both components showed some orientation bias depending on the laminar location, but the bias could be independent of the orientation preferred by single units in the immediate vicinity. The present findings indicate that locally generated field potentials reflect cortical mechanisms for nonlinear integration over wide areas of the visual field.

Determination of trace amounts of urea by using flow injection with chemiluminescence detection

Reaction between urea and hypobromite in alkaline solution was found to produce chemiluminescence with a maximum wavelength at 510 nm. A simple chemiluminescence detection method was used for the determination of urea in human urine and natural aqueous samples, which combined this chemiluminescence reaction with a flow injection analysis system. The relative standard deviation for 5 x 10(-7) mol dm-3 urea is 1.9% (n = 6), and the detection limit is 9.0 x 10(-8) mol dm-3 (3Sr). As this chemiluminescence reaction is very fast, a double concentric tube mixer connected directly to the chemiluminescence cell was used to mix urea solution and hypobromite solution. Alkylamines, carboxylic acids and most amino acids do not interfere in the determination. Ammonium ion interferes, but the sensitivity for ammonium ion is only 1% of that for urea. The interference from ammonium ion was removed sufficiently by using an on-line cation-exchange column.

[Lobectomy under thoracoscopic guidance]

From September '92 to November '93, 15 lobectomies were performed under thoracoscopic guidance. After a thoracoport was inserted through the seventh intercostal space to conduct the operation utilizing a monitor, a six to ten cm incision was made in the fifth intercostal space. The pulmonary arteries and veins were divided after stapling with an Endo GIA or Roticulator 30-VIII. The lobar bronchus was stapled with a Roticulator 30-3.5, 30-4.8 or an Endo TA and affected lobes were resected. In cases of lung cancer, lymph node dissection has become possible as well due to the improvement of endoscopic instrumentation.

[A case of multifocal eosinophilic granuloma presenting as a rib tumor]

A 19-year-old man was hospitalized because of left chest pain. He had a tumor in the left fifth rib with tenderness. Partial resection of the fifth rib was performed. Pathological examination showed granuloma with infiltration of histiocyte-like cells and eosinophils, and S-100 staining was positive. Therefore, the rib tumor was diagnosed as eosinophilic granuloma. Thereafter, the patient had recurrent bone lesions of the mandible, temporal bone, zygomatic bone, scapula, right eleventh rib, and tibia. Radiation therapy was effective for local treatment of each bone lesion. Moreover, pulmonary lesion was suspected on roentgenographic study. However, he had no respiratory symptoms and there was no significant change on roentgenographic findings over six years. It was considered that follow up for detection of bone and pulmonary lesions should be continued in this case.

Right ventricular performance is impaired by full assist of left heart bypass. Analysis of right ventricular performance against change in afterload in heart failure models

The purpose of this study was to assess right ventricular (RV) performance during left heart bypass (LHB) and to determine the optimum LHB driving conditions to preserve RV performance. LHB was established with a centrifugal pump in eight mongrel dogs weighing 11-19 kg. Failing heart models were induced by normothermic aortic clamping for 20 min. RV volume was measured by a conductance catheter, and RV performance was evaluated by two parameters. One was the slope of the RV end-systolic pressure-volume relationship (ESPVR) as a load independent index, and the other was the peak RV pressure (PRVP)-RV stroke volume (RVSV) relationship as a "force-velocity relationship." These parameters were measured during varying assist ratios of LHB at 0% to 100% of pulmonary artery flow, and varying afterload as induced by bilateral intrapulmonary balloon inflation. In failing hearts, RV ESPVR showed an inverse correlation, with the assist ratio of LHB significantly decreasing from 4.23 +/- 1.35 (mmHg/ml) to 3.52 +/- 1.30 (mmHg/ml; P < 0.05) after 100% LHB assist. The correlation between PRVP and RVSV also was inversely linear, the slope of this correlation becoming significantly steeper after 100% LHB assist compared to that without LHB (-0.131 +/- 0.042 vs. -0.051 +/- 0.038, P < 0.005). These two slopes intersected, and this intersection was considered the critical point of afterload above which RVSV was decreased by LHB compared to that without LHB. In addition, reducing the assist ratio made the slope of the PRVP-RVSV correlation significantly more gentle (70%: -0.072 +/- 0.037 vs. 100%: -0.131 +/- 0.042, P < 0.05), with the intersection of the two slopes shifting rightward (i.e., higher afterload). Consequently, the critical level of afterload at 70% LHB assist was significantly higher than that at 100% LHB assist (70%: 38.1 +/- 6.9 vs. 100%: 29.2 +/- 6.8, P < 0.05). Therefore, RV performance against afterload was improved by reducing the assist ratio of LHB. This study demonstrates that RV performance is impaired by full LHB assist if the RV afterload is above the critical level, and that reducing the assist ratio may improve RV performance against afterload.

Diagnostic usefulness of MR imaging for pedunculated hepatocellular carcinoma

Pedunculated hepatocellular carcinoma (HC) is an uncommon tumor of the liver. We present the case of a 56-year-old man with pedunculated HC arising from the lower surface of the liver. We recommend sagittal magnetic resonance imaging, which offers a superior choice of scanning planes, in the diagnosis of pedunculated HC.

Bioabsorbable struts made from poly-L-lactide and their application for treatment of chest deformity

Poly-L-lactide, a polymer of lactic acid, shows slow degradation in living tissue. Poly-L-lactide plate of high molecular weight maintains more than 90% of its initial mechanical properties for more than 3 months after implantation. Using struts made from poly-L-lactide plate, we performed chest wall reconstruction in 56 patients: for postoperative chronic sternal dehiscence in 23 and sternal elevation for pectus excavatum in 33 cases. The postoperative external appearances of the anterior chest were improved in comparison with the preoperative state in all cases. The internal features were evaluated by computed tomographic scan. Neither postoperative wound infection nor respiratory complication was observed, and no tendency for regression of the anterior chest occurred in any of the patients. In 3 of 56 cases (5.4%; one in the sternal dehiscence group and two in the pectus excavatum group), it was necessary to remove part of the strut because of overgrowth of granulation tissue around the implanted material after 4, 12, and 13 postoperative months, respectively. In the pectus excavatum group, the computed tomographic evaluations showed that poly-L-lactide strut maintained sufficient strength to support the thoracic wall 5 months after implantation. These findings suggest that the bioabsorbable poly-L-lactide strut is a promising material for surgical treatment of chest deformity.

[Treatment of hemopneumothorax under thoracoscopic guidance: a case report]

A 32-year-old man was admitted to our hospital complaining of chest pain and increasing dyspnea. Chest X-ray on admission revealed a collapsed lung and an air fluid line in the left hemithorax. Shock developed following drainage of 1,500 ml hemorrhagic pleural fluid. Following blood transfusion, emergency surgery was carried out. At operation under thoracoscopic guidance, a bleeding artery originating from the apex of the thoracic cavity and a bulla on the upper lobe were noted. The artery was successfully ligated with surgical clip, and the bulla was resected using EndoGIA. This case report indicates that hemopneumothorax can be safely operated on under thoracoscopic guidance after the patient has recovered from shock by adequate blood transfusion.

Pigmented ameloblastic fibro-odontoma with melanophages

A case of pigmented ameloblastic fibro-odontoma in the mandible of a 9-year-old Japanese girl is reported. In this tumor, melanin was widely distributed in the nests of the odontogenic epithelial component, and an aggregation of large round melanophages with a large amount of melanin similar to nevus cells was observed in the areas of the connective tissue component. A considerable number of dendritic cells that were considered to be melanocytes were scattered in the epithelial nests. This is the first case of pigmented odontogenic tumor that showed such extensive pigmentation with an aggregation of melanophages.

[A surgical case of achalasia with empyema]

A 57-year-old man who had been complicated with achalasia for thirty years was admitted because of back pain and low grade fever. Chest X-p and Chest CT showed consolidation in the left lower lung field. His respiratory condition was diagnosed as lung abscess preoperatively. After systemic chemotherapy, surgical management was done for both achalasia and this inflammatory respiratory disease. In the operation by left thoracotomy, it was revealed that this case had empyema, not lung abscess. Thus decortication of left lung and esophagomyotomy were performed simultaneously. In the treatment of achalasia, respiratory complications due to aspiration may appear. In addition, it is sometimes difficult to distinguish empyema from lung abscess preoperatively. Therefore much care should be taken during operation in order to treat these respiratory diseases.

[Clinical application of the thoracic balloon for postpneumonectomy patients]

Pneumonectomy may result in complications such as continuous intrathoracic bleeding and mediastinal shift. We used a thoracic balloon made of silicone rubber in 15 postpneumonectomy patients in an attempt to prevent such complications. Two types of thoracic balloons were used in our series. Type 1 thoracic balloon is a simple balloon requiring cooperation with a drainage tube, and Type 2 is a combination balloon and drainage tube. During surgery, air was injected into the thoracic balloon through an air filter. After removal of the thoracic balloon, infusion of sulfur hexafluoride, SF 6, into the thoracic cavity was performed on the 7th to 10th postoperative days. Placement of thoracic balloons in the pleural space after pneumonectomy is a simple, safe and useful method of preventing both intrathoracic bleeding and mediastinal shift.

[Postoperative lung function in patients with funnel chest]

We evaluated the postoperative lung function determined by spirometry in 54 patients with funnel chest (48 males and 6 females: age range, 4-18 years). Thirty-one patients had sternal turnover as corrective surgery, while 23 had sternal elevation with absorbable PLA (polylactic acid) strut. The mean value of vital capacity as a percentage of predicted (%VC) was 97.3% before operation. %VC was decreased at 3 months (80.5%), 6 months (87.4%), 12 months (82.8%), 24 months (85.9%), and 36 months (77.7%) after the operation (p < 0.01). In patients who had sternal elevation, %VC was decreased at 3 months but not at 6 months, 12 months, 24 months, or 36 months after the operation, while %VC was decreased at any point after the operation in patients who had sternal turnover. No significant changes were seen in forced expiratory volume in one second as a percentage of predicted (FEV1.0%), nor in the ratio of residual volume to total lung capacity (RV/TLC). In conclusion, sternal elevation with PLA strut is a better corrective surgery for funnel chest than sternal turnover, because of its less lung function loss after the operation.

Gingival leiomyomatous hamartoma: immunohistochemical and ultrastructural observations

A rare case of leiomyomatous hamartoma of the gingiva is reported and the immunohistochemical and ultrastructural features described. A polypoid mass which presented with the appearance of a congenital epulis was located in the midline of the maxillary alveolar ridge of a two-year-old boy. Histologically, the mass was without a capsule and was composed mainly of irregularly arranged fasciculi of large spindle cells resembling smooth muscle cells. The immunohistochemical staining for desmin was strongly positive in these cells. Many nerve fibers were intermingled with them. Ultrastructurally, the cytoplasm was filled with thin filaments associated with dense patches. Numerous pinocytotic vesicles were present on the cytoplasmic membrane. These findings indicated that the mass consisted mainly of mature smooth muscle cells. The clinical and histological features suggest that the smooth muscle cells in the lesion are of hamartomatous or choristomatous origin, in contrast to true leiomyoma or granular cell congenital epulis.

[Hemodynamic changes in acute pancreatitis]

Hemodynamics studies were carried out from days 1-5 following the onset of illness in 7 patients with severe pancreatitis (group A) and in 7 patients with moderate pancreatitis (group B). Patients in both groups had a higher cardiac index (CI) and a lower systemic vascular resistance (SVR) than normal patients during 5 days of illness, and patients in group A had a higher CI of 5.38 +/- 0.841 x min/m2 and lower SVR of 889 +/- 234dyn.sec/cm5 than those in group B on day 4. Patients in group A had a lower pulmonary vascular resistance than normal patients on days 1, 3, and 4, but those in group B did not show this hemodynamic change. Group A patients had a higher pulmonary wedge pressure of 11.9 +/- 8.4mmHg and depressed left ventricular stroke work index of 59.8 +/- 17.8g.m/m2 as compared with group B (5.6 +/- 3.4mmHg, 77.7 +/- 23.6g./m2, respectively). These findings indicate that a hyperdynamic hemodynamic state may exist in the early stages of moderate and severe pancreatitis and myocardial depression may be evident in severe pancreatitis.

A standardized method of using nude mice for the in vivo screening of antitumor drugs for human tumors

Human tumors transplanted into nude mice have long been used to assess the effectiveness of antitumor drugs and yet there is still no established standard method in preclinical practice for screening new antitumor drugs in vivo using nude mice. Thus, a cooperative study on the feasibility of a human tumor/nude mouse system for the in vivo screening of drugs was conducted by the Japanese Research Society for Chemosensitivity of Cancer. Two human stomach cancers, H-111 and SC-6-JCK, and one human colon cancer, Co-4, were transplanted serially into nude mice and used as gastrointestinal tract tumors with stable tumor growth. The appropriate dosage of six well-known antitumor drugs [mitomycin C (MMC), cyclophosphamide (CPA), nimustine hydrochloride 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), cis-platinum (II) diaminodichloride (CDDP), adriamycin (ADM) and 5-fluorouracil (5-FU)] in human tumor-bearing nude mice was determined based on the maximum tolerance dose of the drug. The respective dosages were 6 mg/kg of MMC x 1 (i.p.), 120 mg/kg of CPA x 1 (i.p.), 30 mg/kg of ACNU x 1 (i.p.), 8 mg/kg of CDDP x 1 (i.p.), 8 mg/kg of ADM x 1 (i.v.), and 50 mg/kg of 5-FU q4d x 3 (i.p.). Three weeks after treatment, drug effectiveness was judged by the tumor growth inhibition rate. Treatment with these appropriate doses appeared to show the maximum effect of the respective drugs on the tumor-bearing nude mice.(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical treatment of metastatic lung tumors]

From January 1970 to March 1991, 72 operations in 55 patients (31 males and 24 females) with metastatic lung tumors were performed in our department. Their cumulative survival rates was 25.5% at five years. With analysis of the various prognostic factors, patients both with solitary metastases and without lymph node metastases had a good prognoses. However, even in patients with recurrent lung metastatic tumors, long time survival was achieved with reoperation in two patients. We concluded that reoperation with or without effective chemotherapies was effective in selected patients.

Plasma levels of superoxide dismutase and its isomers in patients with chronic renal disease

To evaluate the significance of Cu,Zn-superoxide dismutase (SOD) in chronic renal disease, we evaluated the plasma SOD activity and analyzed the plasma Cu,Zn-SOD isomers employing gel column chromatography. The plasma SOD activity was determined as the biological activity using the nitrite method and the Cu,Zn-SOD concentration was assayed from the immunological activity using enzyme-linked immunosorbent assay (ELISA). The subjects comprised 185 patients with chronic glomerular disease and 20 hemodialysis patients. Plasma from 170 healthy persons was employed as a control. Both the plasma biological activity and plasma level of Cu,Zn-SOD determined by ELISA were elevated in patients with chronic glomerular disease. In hemodialysis patients, a marked increase in Cu,Zn-SOD level (ELISA) was noted in comparison with the increase in SOD biological activities. Gel column chromatography demonstrated a marked increase in Cu,Zn-SOD monomer which was enzymatically inactive. From these results, we conclude that a marked elevation of the plasma level of Cu,Zn-SOD in hemodialysis patients was caused by an increase in the enzymatically inactive Cu,Zn-SOD monomer.

[Bullectomy utilizing EndoGIA under thoracoscopic guidance]

We report 5 cases of pneumothorax successfully treated with an endoscopic GIA stapling device (EndoGIA) under thoracoscopic guidance. There were no complications such as air leak or bleeding, and patients were discharged 2 to 7 days after operation. Surgical procedure utilizing EndoGIA has been proved to have advantages such as less pain, early return to normal activity and more cosmetic incision.

Suppression of plasma endothelin-1 level by alpha-human atrial natriuretic peptide and angiotensin converting enzyme inhibition in normal men

The effect of synthetic alpha-human atrial natriuretic peptide (alpha-hANP) on plasma endothelin-1 (ET-1) level was examined in 6 healthy subjects. Intravenous infusion of alpha-ANP (0.1 micrograms/kg/min) resulted in significant falls in plasma renin activity and aldosterone, but without effect on ET-1 level. An angiotensin converting enzyme inhibitor, captopril, increased plasma renin activity and decreased aldosterone, respectively. However, plasma ET-1 levels were not modified by captopril. In cases with alpha-hANP infusion after captopril (25 mg, p.o.,), the renin-angiotensin-aldosterone system was further inhibited compared with the first group, and ET-1 at 60 min was significantly suppressed from the baseline. These data suggest that alpha-hANP when combined with captopril brings about the suppression of plasma ET-1 concentrations in men.

Functional integrity of hepatocyte canalicular membrane transport of taurocholate and bilirubin diglucuronide in Eisai hyperbilirubinuria rats

Eisai hyperbilirubinuria rats (EHBR) are characterized by conjugated hyperbilirubinemia, and impaired or defective excretion of bilirubin, reduced glutathione and other organic anions from hepatocytes. Hepatocyte canalicular membrane vesicles (CMV) from EHBR and normal SD rats were studied with regard to taurocholate (TC) transport driven by ATP or a membrane potential and bicarbonate-stimulated bilirubin diglucuronide (BDG) transport. ATP-dependent uptake or association of BDG with CMV was also studied in both strains of rats. No significant differences in the uptake of TC and BDG by CMV were observed. This indicates the functional integrity of the canalicular transporters for both organic anions in EHBR. Biliary excretion of taurolithocholic acid sulfate (TLCS) is defective in EHBR. However, TLCS inhibited ATP-dependent TC uptake by SD rat CMV competitively, which may be against the hypothesis that a common organic anion carrier is defective in canalicular membranes of jaundiced rats.

Studies on pyridonecarboxylic acids. 1. Synthesis and antibacterial evaluation of 7-substituted-6-halo-4-oxo-4H-[1,3]thiazeto[3,2-a]quinoline-3- carboxylic acids

A series of [1,3]thiazeto[3,2-a]quinoline-3-carboxylic acids and their esters were prepared and evaluated for antibacterial activity. The derivatives with a hydrogen or methyl group at C-1, fluorine at C-6, and piperazinyl or 4-methyl-1-piperazinyl group at C-7 showed superior in vitro antibacterial activity, and the derivatives with 4-methyl-1-piperazinyl group at C-7 had potent in vivo activity. Compound 29a (NM394) showed excellent in vitro antibacterial activity and low toxicity but poor absorption from the gastrointestinal tract. Compound 29ee (NM441), an N-[(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl] derivative of 29a, was found to possess a favorable pharmacokinetic profile and oral activity superior to that of ciprofloxacin in experimental animals.

[Changes of plombage-operations in respiratory surgery]

The first plombage-operation for pulmonary tuberculosis was by Dr. Nagaishi (1947) and Dr. Wilson, who developed the plombage method employing hollow polymethylmethacrylate spheres. Although the method presented a relatively effective option at a time when no effective drugs were available, its use was discontinued because of such complications as lung injury, cavity-perforation, and empyema. Therefore, soft elastic resin materials, such as those used in sponge-plombage and air-plombage, replaced the hard resin materials. Each plombage method is associated with a certain medical historical period, in Japan. Still the "Kinchyu" method was used. However, the complication of chronic empyema with bronchopleural fistula was difficult to treat. A notable recent method is the pedicled omentum plombage method, which is effective in the treatment of patients who have not responded to standard operations. Finally there was surely a clinical significance in each medical historical period.