[Effect of preoperative chemotherapy for bulky N2 non-small-cell lung cancer]

The effect of chemotherapy as the adjuvant therapy to bulky N2 disease (stage IIIA) non-small-cell lung cancer was examined. From January 1992 to December 1996, 464 patients with non-small-cell lung cancer underwent surgery. Seven patients (1.5%) with N2 disease (stage IIIA) received two cycles of preresectional cisplatin and vindesin chemotherapy, followed by standardized surgical resection (Group A). 46 patients (9.9%) had pathological N2 disease (T1-3, M0) after surgery (Group B). In Group A a complete resection was accomplished in two patients (28.6%), and five patients had incomplete resection with a deseased margin, followed thoracic irradiation 60 to 75 Gy. In three patients in Group A the N2 disease was pathologically downstaged to N1 or N0 disease. Overall survival at five years in Group A and in Group B was 48% and 39%, and median survival time was 49 months and 38 months. Although complete resection rate was lower in Group A (28.6%) than in Group B (78.2%), there was no significant difference between five year survival and median survival time in Group A and Group B. These data may be thought to suggest that induction chemotherapy in Group A was effective on occult micrometastatic disease.

Improved human islet isolation by a tube method for collagenase infusion

BACKGROUND

Collagenase infusion into the pancreatic duct is an essential step in human islet isolation. We developed a new method for ductal canulation and collagenese infusion.

METHODS

A total of 53 pancreata were divided into two groups: group 1 (n=23), the new tube method, and group 2 (n=30), the standard angiocatheter method. In group 1, a polyethylene tube was inserted into the duct and pushed to the tail. The tail was first expanded, followed by expansion of the body and then the head, by pulling out the tube.

RESULTS

Total islet number and number/g pancreas (mean+/-SE) were significantly higher in group 1 (481,123+/-43,218 and 8,010+/-722) (mean+/-SE) than in group 2 (300,974+/-35,122 and 5,090+/-515, P<0.01). Total islet equivalent number and islet equivalent number per gram pancreas were also significantly higher in group 1 (319,176+/-39,354 and 5,455+/-652) than in group 2 (202,022+/-23,331 and 3,722+/-468, P<0.04). Islet purity and fragmentation showed no differences between the groups.

CONCLUSIONS

The tube method improved islet yields. We recommended this method for human islet isolation.

Myelin deficiencies in both the central and the peripheral nervous systems associated with a SOX10 mutation

We describe an unique patient presenting with severe leukodystrophy compatible with Pelizaeus-Merzbacher disease and peripheral neuropathy consistent with Charcot-Marie-Tooth disease type 1 in addition to Waardenburg-Hirschsprung syndrome. A novel mutation was identified in her SOX10 gene, which encodes a transcription factor preferentially expressed in the late embryonic glial cell lineage and in mature myelin-forming cells of both the central nervous system and peripheral nervous system, as well as in the early neural crest cells. Heterozygous SOX10 loss-of-function mutations have been reported in patients with Waardenburg-Hirschsprung syndrome and its murine model, Dominant megacolon. However, neither Waardenburg-Hirschsprung syndrome patients nor Dominant megacolon mice have dysmyelinating features, suggesting the question of how SOX10 acts in the glial lineage in vivo. The novel mutation described herein does not disrupt the coding region but extends the peptide and hence is likely to act as a dominant-negative allele. Our findings indicate that dysfunction of SOX10 may lead to deficiency of myelination in the central nervous system and peripheral nervous system as well as hypopigmentation and enteric aganglionosis.

Exercise-induced rise in arterial potassium in patients with chronic heart failure

OBJECTIVES

In patients with chronic heart failure (CHF), exercise is frequently associated with skeletal muscle fatigue and breathlessness due to heightened ventilatory response. The exercise-induced rise in potassium, which is released from the exercising skeletal muscle, has been implicated in ventilatory control during exercise. The aim of the present study was to determine whether the exercise-induced rise in arterial potassium is altered in patients with CHF and to examine the relationship between increased exercise ventilation and exercise-induced hyperkalemia in patients with CHF.

METHODS AND RESULTS

We evaluated 88 patients with CHF (25 patients were in class I, 35 in class II, and 28 in class III according to the New York Heart Association functional classification) and 14 normal subjects. Subjects performed symptom-limited ergometer exercise while expired gas, arterial blood gas, and arterial potassium were analyzed. The increases in ventilation (deltaV(E)), effective alveolar ventilation (deltaVA), and carbon dioxide output (deltaV(CO2)) from rest to peak exercise decreased as the severity of CHF advanced. The ratio of deltaV(E) to deltaV(CO2) was significantly elevated in class III patients, although there was no difference in the ratio of deltaVA to deltaV(CO2) among the four groups. Rest and exercise arterial P(CO2) did not differ among the four groups and was controlled within the normal range. The increase in arterial potassium (deltaK+) from rest to peak exercise was markedly reduced as the severity of CHF advanced: (mean +/- SD) 1.70+/-0.32 mmol/L in normal subjects; 1.46+/-0.27 mmol/L in class I patients; 1.15+/-0.24 mmol/L in class II patients; and 0.78+/-0.24 mmol/L in class III patients. The ratios of deltaVA or deltaV(CO2) to deltaK+ were not different among the four groups. The ratio of deltaV(E) to deltaK+, however, was significantly greater in patients in class III than in normal subjects or patients in class I or II.

CONCLUSIONS

The deltaK+ from rest to peak exercise was markedly reduced as the severity of CHF advanced. The increased exercise ventilation due to increased physiologic dead space in severe CHF was not accompanied by the corresponding augmentation of exercise-induced hyperkalemia. Exercise-induced hyperkalemia does not contribute to the increased ventilatory drive to keep normal arterial P(CO2) during exercise in the presence of increased physiologic dead space in severe CHF.

Absence of plasma protease-antiprotease imbalance in the formation of saccular cerebral aneurysms

OBJECTIVE

We examined the hypothesis that a plasma protease-antiprotease imbalance contributes to the formation of saccular cerebral aneurysms and the suggestion that the assay of these enzymes might be a screening tool for people at higher risk for aneurysm formation.

METHODS

From June 1997 through May 1998, the plasma leukocyte elastase, which is an important proteolytic enzyme, and alpha-antitrypsin and alpha2-macroglobulin, which are important antiproteolytic enzyme plasma proteins, were examined in 18 patients with ruptured aneurysms, 9 patients with unruptured aneurysms, and 22 controls.

RESULTS

The elastase:alpha1-antitrypsin ratio and the elastase:alpha2-macroglobulin ratios were significantly higher in patients with ruptured aneurysms within 24 hours after subarachnoid hemorrhage (SAH) than in the controls. The protease-antiprotease imbalance depended on the elevation of the elastase level, which might be correlated with leukocytosis after SAH. The elastase level decreased to the control level 3 months after the onset of SAH. No significant difference in the elastase:alpha1-antitrypsin and elastase:alpha2-macroglobulin ratios was observed between the patients with unruptured aneurysms and the controls.

CONCLUSION

These results do not support the hypothesis that a plasma protease-antiprotease imbalance is a potential marker to predict the formation of saccular cerebral aneurysms. The increase in plasma elastase levels in patients with ruptured aneurysms might be attributable to leukocytosis after SAH.

[Effect of vasodilators on femoral-to-radial arterial pressure gradient after cardiopulmonary bypass]

In 57 adult patients undergoing valve replacement surgery or valve plastic surgery, pressure gradient between the femoral and radial artery was evaluated after cardiopulmonary bypass (CPB). During CPB, the rectal temperature was kept at mild or moderate hypothermia. Nitrates and prostaglandin E1 were administered in all patients during operation. Patients were divided into two groups; Group A of 31 patients who had history of hypertension and received some vasodilators up to the operation, and Group B of 27 patients who had no history of such medication. There was no difference in patient's characteristics, anesthetic time, CPB time and aortic cross clamping time between the two groups. There was a significant difference between the pre-CPB and post-CPB in hematocrit data. Systemic vascular resistance (SVR) decreased significantly from the pre-CPB level to the post-CPB level. There was no significant difference between Group A and Group B in SVR, but a higher femoral-to-radial artery pressure gradient was observed in Group A until the end of operation. Hypertension and the use of vasodilator change the tone of peripheral blood vessels and intensify femoral-to-radial artery pressure gradient after CPB.

A case of vasospastic angina presenting Brugada-type ECG abnormalities

An electrophysiological study and a provocative test of coronary artery spasm was attempted in a 68-year-old man who was having syncopal attacks and chest pain. His electrocardiogram had the characteristics of Brugada syndrome and ventricular fibrillation (VF) was induced by programmed electrical stimulation. ST-segment elevation became exaggerated by procainamide, which could not prevent the induction of VF. Coronary angiography revealed no stenotic lesions, and spasm in the left coronary artery was induced by intracoronary administration of acetylcholine with similar chest pain to that experienced before. Under treatment with diltiazem and flecainide, which suppressed the induction of VF, the patient experienced no recurrence of symptoms despite persistent ST-segment elevation. No previous reports have described coronary spasm associated with Brugada-type ECG abnormalities, and patients with syncope should be evaluated carefully.

Left ventricular free wall rupture in acute fulminant myocarditis during long-term cardiopulmonary support

A 77-year-old woman with acute myocarditis developed cardiogenic shock soon after admission and was given mechanical cardiopulmonary support. Echocardiography revealed severe global left ventricular hypokinesia. After 5 days of mechanical support, left ventricular wall motion gradually began to improve, but the patient died of cardiac tamponade on day 13. At necropsy, a free wall rupture was found where the apical akinetic area bordered the basal portion, an area which had shown better wall motion. Left ventricular free wall rupture in acute myocarditis has not been reported, but this case indicates that it may occur in fulminant myocarditis when a cardiopulmonary support system is used.

Self-assembly of synthetic glycolipid/water systems

Glycolipids (amphiphiles that bear oligosaccharides as their hydrophilic headgroups) are of importance both scientifically and technically. This review describes recent advances in our understanding of the molecular correlations in phase behavior in aqueous glycolipids over the past several years. In the first part, we discuss how headgroup stereochemistry affects the phase behavior of glycolipids both in two- and three-dimensional systems. In the second part, we discuss the effects of alkyl chain structure and phase behavior of phytanyl-chained glycolipid/water systems. The physical properties of glycolipid/water systems depend strongly on the inter-headgroup interactions that are related to such factors as stereochemistry (conformation) and size of headgroups, type of sugar residues involved, alkyl chain structure, etc. Thus, apart from the conventional concept like 'hydrophilic/lipophilic balance', explicit accounts of headgroup interactions are crucial to control the particular glycolipid/water system concerned. This is in marked contrast to the conventional amphiphile/water systems where the inter-headgroup interactions are in most cases simply repulsive.

Occurrence of ganglioside GD3 in neoplastic astrocytes. An immunocytochemical study in humans

GD3 immunocytochemical analysis was performed in 25 human specimens obtained by autopsy and biopsy from patients with astrocytomas, anaplastic astrocytomas, cerebellar astrocytomas and glioblastoma multiforme (GM), using the ABC method. Extraction of the ganglioside fraction from GM was used for thin-layer chromatography (TLC) analysis to confirm the specificity of anti-GD3 monoclonal antibody (DSG-1). Normal astrocytes were not immunoreactive for GD3. Neoplastic astrocytes of low- to high-grade tumours were GD3 immunoreactive. In GM, the multinucleated giant cells were also immunoreactive. All immunoreactivity present was within the cytoplasm. In TLC analysis, enzyme immunostaining of gangliosides from GM with DSG-1 showed only one positive band, which had the same TLC migration rate as GD3, indicating that GD3 of the ganglioside fraction from GM is the antigen detected by DSG-1. The presence of GD3 within the cytoplasm of neoplastic astrocytes showing invasive and proliferative properties, is of considerable interest. The implications and possible significance of the presence of GD3 in the cytoplasm in glioma cells are discussed.

Hypotension induced by exercise is associated with enhanced release of adenyl purines from aged rat artery

To determine whether the antihypertensive effects of exercise are associated with release of ATP and its metabolites from arteries, we assayed blood pressure and the release of adenine nucleotides and nucleosides from the caudal arteries of exercised and sedentary aged hypercholesterolemic rats. Exercise on a treadmill for 12 wk significantly decreased the rise in systolic and diastolic blood pressure by 7.5 and 15.9%, respectively, with advanced age. The concentrations of oleic, linoleic, and linolenic acids in the caudal artery decreased significantly with exercise, demonstrating an association between exercise and the unsaturation index of caudal arterial fatty acids. The amounts of total adenyl purines released by the arterial segments from exercised rats, both spontaneously and in response to norepinephrine, were significantly greater by 80.0 and 60.7%, respectively, than those released by tissues from sedentary rats. These results suggest that exercise alters the membrane fatty acid composition in aged rats as well as the release of ATP from vascular endothelial cells and that these factors are associated with the regression of the rise in blood pressure normally observed with advanced age.

Cerebral blood flow in patients with normal pressure hydrocephalus

Mean cerebral blood flow (CBF) of the whole brain was measured in 48 patients who underwent cerebrospinal fluid shunt surgery for normal pressure hydrocephalus (NPH) by performing first-pass radionuclide angiography using 99Tcm-hexamethylpropylene amine oxime. Patients were divided according to outcome into an 'excellent' improvement group, a 'good' improvement group, a 'fair' improvement group and a 'poor' improvement group. Patients with excellent and good improvement had a preoperative mean CBF of 40.4 +/- 3.9 ml.100 g-1.min-1 and 37.1 +/- 5.5 ml.100 g-1.min-1, respectively, both of which were significantly (P < 0.005) higher than that in 11 patients who showed fair improvement (30.8 +/- 3.2 ml.100 g-1.min-1) and six patients who showed poor improvement (31.8 +/- 2.5 ml.100 g-1.min-1). Patients with a clinical improvement after shunting had an increased postoperative mean CBF. We conclude that patients with a preoperative mean CBF of over 35 ml.100 g-1.min-1 can show favourable improvement after a shunting procedure, and that the preoperative mean CBF of 32 ml.100 g-1.min-1 can be considered the critical level for treatment.

Induction of protective T cells against Listeria monocytogenes in mice by immunization with a listeriolysin O-negative avirulent strain of bacteria and liposome-encapsulated listeriolysin O

Only listeriolysin O (LLO)-producing strains of Listeria monocytogenes generate protective immunity in mice. Based on the findings that endogenous gamma interferon (IFN-gamma) production was induced only by such strains and that purified LLO could induce IFN-gamma from NK cells, we have postulated that LLO may play a pivotal role in the induction of Th1-type protective T cells, which are highly dependent on IFN-gamma. In this study, mice were immunized with L. monocytogenes ATCC 15313, an LLO-nonproducing avirulent strain, along with LLO encapsulated in liposome (LLO-liposome). LLO-liposome was highly potent in the induction of various cytokines, including IFN-gamma. Immunization of mice with either LLO-liposome or the viable strain ATCC 15313 alone did not induce protection against challenge infection. In contrast, the combination of LLO-nonproducing bacteria plus LLO-liposome induced a significant level of protective immunity mediated mainly by Th1-type cells capable of producing a large amount of IFN-gamma in an antigen-specific manner. The protection afforded by the combination was not dependent on LLO-specific cytotoxic T cells. These results support the idea that the inability of an LLO-nonproducing avirulent strain or killed bacteria to induce the generation of protective T cells is due not to the lack of a central T-cell epitope(s) but to the lack of ability to induce the production of endogenous cytokine during the early stage of immunization; the results also suggest that an appropriate use of LLO at least in an animal model may be effective in the induction of antigen-specific Th1-dependent protective immunity to various kinds of intracellular parasitic bacteria.

Demonstration of ganglioside GD3 in human reactive astrocytes

Astrocytes are the cells that actively participate in the process of lesion repair in the central nervous system (CNS), and reactive astrocytosis of varying degrees becomes apparent with time in any pathological condition occurring in the normally developed postnatal CNS. Ganglioside GD3 (II3a(NeuAca2-8NeuAc)-LacCer, GD3) in reactive astrocytes from autopsied patients with Creutzfeldt-Jakob disease (CJD) and old cerebral infarction was investigated immunocytochemically, using mouse IgM anti-GD3 monoclonal antibody (DSG-1). Reactive astrocytes in CJD and cerebral infarction demonstrated GD3-immunoreactivity within the cytoplasm. Normal astrocytes were negative. The present data raise the possibility that GD3 in reactive astrocytes has biological implications for the properties of the cells, such as cellular motility.

The hypotensive effect of docosahexaenoic acid is associated with the enhanced release of ATP from the caudal artery of aged rats

Fish oils have been shown to lower blood pressure in hypertensive subjects. To determine the mechanism of this hypotensive effect, we examined the effects of docosahexaenoic acid (DHA), one of the (n-3) polyunsaturated fatty acids in fish oil, on blood pressure and on the release of adenyl purines, such as ATP, ADP, AMP and adenosine, from the caudal arteries of aged rats. Aged female Wistar rats (100 wk) were fed a high cholesterol diet and were administered intragastrically ethyl all-cis-4,7,10,13,16,19-docosahexaenoate [300 mg/(kg.d)] for 12 wk (DHA group) or vehicle alone (control group). Compared with the controls, rats supplemented with DHA had significantly greater (10.1%) DHA concentrations in the caudal arteries. This was associated with more total (n-3) arterial fatty acids, a greater unsaturation index of arterial fatty acids, 43.9% lower plasma noradrenaline levels and the repression of the elevation in blood pressure observed with advancing age. The amount of purines released, both spontaneously and in response to noradrenaline, from arterial segments of DHA-supplemented rats was significantly higher than that released from tissues of control rats. Regression analysis revealed significant negative relationships between the total amount of purines released from the artery and the systolic (SBP) and diastolic (DBP) blood pressures. These results suggest that in aged rats, supplementation with DHA alters the membrane fatty acid composition as well as the amount of ATP released from vascular endothelial cells and decreases plasma noradrenaline, and that these factors may ameliorate the rise in blood pressure normally associated with advancing age.

Long-term supplementation with a high cholesterol diet decreases the release of ATP from the caudal artery in aged rats

We examined the effects of high cholesterol (HC) diet on the spontaneous and noradrenaline-induced release of ATP, ADP, AMP and adenosine from caudal arteries and on the plasma levels of these adenyl purines in aged (100-week-old) Wistar rats. Administration of this diet for 12 weeks significantly reduced spontaneous and noradrenaline (1 micromol/L)-evoked release of adenyl purines from the caudal arteries relative to rats given the control diet The unsaturation index of fatty acids (UI), which gives the average number of double bonds, of both the plasma and the caudal artery was significantly less in the HC diet-fed rats than in those fed the control diet. The HC diet for 12 weeks produced a slight but significant increase in systolic and diastolic blood pressure with advancing age. Regression analysis revealed a significant inverse relationship between the total amount of purines released from the artery and diastolic blood pressure, and also a positive relationship between the total amount of purines released and the UI of the caudal artery. These results suggest that the high cholesterol diet decreased the release of adenyl purines from the caudal arteries of aged rats, leading to an increase in blood pressure.

Analysis of exploratory eye movement in a patient with lupus psychosis

The psychiatric and cognitive condition of a patient with lupus psychosis was evaluated. Using a device that detects the corneal reflection of infrared light, the patterns of eye tracking movements were recorded before the onset of lupus psychosis, after remission, and again 1 year later. Electroencephalographic findings and cerebrospinal fluid levels of both interferon alpha and interleukin-6 were also obtained longitudinally. Electroencephalographic findings and clinical signs were correlated to the levels of interferon alpha in cerebrospinal fluid. Analysis of exploratory eye movements revealed marked decreases in the number of eye fixation, mean eye-scanning length and total eye-scanning length. Even though the lupus psychosis resolved and the electroencephalographic findings became normal, the eye movement patterns showed remaining deterioration. It was concluded that analysis of exploratory eye movements in patients with systemic lupus erythematosus may be useful in diagnosing lupus psychosis, and may also present a diagnostic clue to subclinical lupus psychosis.

Optimum tube voltage for chest radiographs obtained by psychophysical analysis

Many kinds of x-ray films having various characteristic curves have been developed for chest radiographs. In general, a phototiming device for determination of a mAs value which gives a proper exposure has been used for a chest radiography. For each film, however, the x-ray tube voltage has been determined by the subjective evaluation of radiologists or radiological technologists. In this paper, we propose a new method for determining the optimum tube voltage for chest radiographs using psychophysical analysis. The optimum density and the optimum density range of a screen/film system are obtained from the gradient curve of film and the minimum perceptible contrast delta Dmin [Acta Radiol. Diagnos. 4, 463-476 (1966)]. The optimum tube voltage, by which the lowest density of a mediastinum and the highest density of a lung field just cover the optimum density range, is obtained using the x-ray photon spectrum and sensitivity spectrum of the screen. This objective method does not depend on personal subjective evaluation, therefore it is available for the determination of optimum tube voltage for chest radiographs to be observed by many doctors of various departments.

[Usefulness of CT-guided aspiration biopsy in combination with rapid cytology for diagnosis of benign pulmonary lesions]

PURPOSE

To evaluate the diagnostic accuracy of computed tomography (CT)-guided aspiration biopsy in combination with rapid cytology for benign pulmonary lesions.

MATERIALS AND METHODS

We performed percutaneous aspiration biopsy under CT guidance in combination with a rapid cytologic examination in 91 patients with pulmonary lesions. A 21-gauge modified Menghini needle coaxially placed through an 18-gauge needle was used in this procedure. Thirty-one lesions that were confirmed as a benign pulmonary lesion histologically, serologically, bacteriologically and/or clinically were evaluated in this study.

RESULTS

In 28(90.3%) of 31 lesions, sufficient material for cytologic diagnosis was obtained from the aspiration biopsy. Specific benign diagnosis for benign disease was obtained in 13 lesions (41.9%), while nonspecific diagnosis for benign disease was obtained in 15 lesions (48.4%). The overall accuracy of the rapid cytological examination was 90.3%. Pneumothorax developed in 17 patients (54.8%), with 7 patients (22.6%) requiring chest tube drainage. Only one patient complained of mild hemoptysis, which subsided with hemostatic agents.

CONCLUSION

Percutaneous aspiration biopsy combined with a rapid cytologic diagnosis provides a high degree of accuracy in the diagnosis of benign pulmonary lesions.

[Clinical evaluation of Dumon stent for tracheobronchial stenosis due to advanced esophageal carcinoma]

We inserted Dumon stent to 13 patients with tracheobronchial stenosis due to advanced or recurrent esophageal carcinoma. Severe dyspnea was improved in 11 patients except for 2 patients with bilateral recurrent nerve palsy. 3 cases who had radiation therapy or chemotherapy lived over 150 days. We inserted esophageal stent in 4 cases. 2 patients died due to hemoptysis after 156 days and 35 days. We conclude that Dumon stent is one of the useful treatments in order to improve quality of life and prognosis of advanced or recurrent esophageal carcinoma.

Effect of percutaneous transvenous mitral commissurotomy on postexercise breathlessness as determined by ventilation during recovery from constant workload exercise

We evaluated the effect of percutaneous transvenous mitral commissurotomy (PTMC) on ventilatory variables and dyspnea during recovery from a 6-minute submaximal constant workload exercise, and showed that the decrease in postexercise ventilation after PTMC was closely related to improvement in postexercise dyspnea after PTMC. Ventilation during recovery from submaximal constant workload exercise is related to postexercise breathlessness and can be used to assess the effectiveness of therapeutic interventions.

[Formation of genetic polymorphism in connection with phylogenesis and microevolution of the domestic dog Canis familiaris L]

The analysis of genetic relationships between numerous breeds and populations of domestic dogs of Asian and European origin was performed by studying their polymorphism for 14 loci of biochemical markers. Phylogenetic positions of different breed groups, related to one another and to ancestral forms from the center of domestication, were elucidated. Directions of gene flow in the formation of breed as well as dynamics and vectors of the forming genetic structure in microevolution of this extremely polytypic species, were established.

Specification of motor neuron identity by the MNR2 homeodomain protein

Sonic hedgehog signaling controls the differentiation of motor neurons in the ventral neural tube, but the intervening steps are poorly understood. A differential screen of a cDNA library derived from a single Shh-induced motor neuron has identified a novel homeobox gene, MNR2, expressed by motor neuron progenitors and transiently by postmitotic motor neurons. The ectopic expression of MNR2 in neural cells initiates a program of somatic motor neuron differentiation characterized by the expression of homeodomain proteins, by neurotransmitter phenotype, and by axonal trajectory. Our results suggest that the Shh-mediated induction of a single transcription factor, MNR2, is sufficient to direct somatic motor neuron differentiation.

Comparison of arrhythmogenicity of atrial pacing at several right atrial pacing sites: evaluation of canine atrial electrograms during atrial pacing and arrhythmogenicity for atrial fibrillation

The changes in the duration of atrial electrograms and the appearance of AF during atrial pacing were compared among five atrial pacing sites in dogs to clarify the arrhythmogenicity of atrial pacing at different atrial pacing sites. In seven mongrel dogs (15-20 kg), the right atrial surface was exposed by right thoracotomy. Atrial electrograms were recorded via bipolar electrodes with an interelectrode distance of 1.2 mm at four right atrial sites: (1) the high right atrium (HRA), (2) the mid-right atrium (MRA), (3) the low right atrium (LRA), and (4) the center of the pectinate muscle (PM). The duration of the atrial electrograms at these four recording sites were measured during atrial pacing with fixed cycle lengths of 200, 150, and 120 ms delivered at five atrial sites: (1) the HRA, (2) the inferior vena cava (IVC), (3) the right atrial appendage (RAA), (4) Bachman's bundle (BB), and (5) the atrial septum (AS). In each dog, the atrial pacing with the 120-ms cycle length was performed five times at each pacing site to evaluate the inducibility of AF. When AF was induced, the atrial recording site which first showed a fragmented atrial electrogram was considered the initiation site of the AF. AF was induced during 9 of 35 episodes of atrial pacing at the HRA site, 11 of 35 at the IVC site, 5 of 35 at the RAA site, 3 of 35 at the BB site, and none at the AS site. The initiation site of AF was in the HRA site in 11 of 28 episodes of induced AF, in the MRA site in 9 of 28, and in the LRA site in 8 of 28. At each recording site, the shorter the paced cycle length, the longer the duration of the atrial electrogram regardless of the pacing site. During the atrial pacing with the 200-ms cycle length, the HRA pacing resulted in the shortest duration of the atrial electrogram at each recording site in comparison with the other pacing sites. However, during atrial pacing at the two shorter paced cycle lengths, the duration of the atrial electrogram was shorter during the pacing at the BB or AS sites in comparison with the other three pacing sites, i.e., the HRA, IVC, and RAA sites. These results were the same for all atrial recording sites, but the prolongation of the atrial electrogram was most prominent at the HRA and MRA recording sites, which are most likely initiation sites of the induced AF. In the canine atria, (1) the initiation sites of AF were likely to be the HRA, MRA, or LRA sites in comparison with the PM site; and (2) the atrial pacing at the BB or AS sites was considered less arrhythmogenic for AF than the pacing at the HRA, LRA, or RAA sites.

Liposome drug delivery system for murine neuroblastoma

PURPOSE

The effects of liposome-infused doxorubicin on C-1300 murine neuroblastoma were studied. The liposome surface was covered with polyethylene glycol to avoid migration toward the reticuloendothelial system and to prolong its presence in the bloodstream. Liposome-infused doxorubicin hydrochloride (DXR), an anthracycline was used as an anticancer antibiotic substance.

METHODS

Each A/J mouse was transplanted with 1 x 10(5) C-1300 murine neuroblastoma cells subcutaneously in the thigh. The experiment was conducted when the maximum tumor dimension was 1 cm. The control group was given only physiological saline solutions, the second group was given DXR alone, and the third group received liposome-infused DXR (Lip-DXR). The survival and doubling times were measured. One, 12, and 24 hours after the injection, the DXR concentration in the cardiac tissues was measured for statistical comparison.

RESULTS

The survival time of the mice was found to be 27+/-5.10 days in the control group, 31.40+/-3.15 days in the DXR group, and 43.86+/-2.13 days in the Lip-DXR group. The Lip-DXR group showed the longest survival time. The tumor-doubling time was found to be 9.07+/-2.30, 10.75+/-3.49, and 19.80+/-3.26 days, for each group, respectively. When comparing the DXR concentration in the heart tissues, the Lip-DXR-administered mice showed significantly lower DXR accumulation in the cardiac tissues after 1 and 12 hours than the DXR-administered mice.

CONCLUSION

This study proved that liposome-infused DXR could be used effectively on murine neuroblastoma (C-1300 tumor cell model) and may reduce the incidence of cardiac toxicity as compared with DXR alone.

Cerebral blood flow measurement in patients with impaired consciousness: usefulness of 99mTc-HMPAO single-photon emission tomography in clinical practice

The relationship between impairment of consciousness and quantitative cerebral blood flow (CBF) was investigated. The mean CBF of the whole brain was measured by the Patlak-plot method using technetium-99m hexamethylpropylene amine oxime single-photon emission tomography (99mTc-HMPAO SPET) in patients with the following diseases: cerebral infarction, intraparenchymal haemorrhage, subarachnoid haemorrhage, brain tumour and cerebral contusion. The clinical symptoms were evaluated according to the severity of impaired consciousness, aphasia and dementia. Four hundred and eighty-five CBF measurements were performed. Patients with alert consciousness showed an age-related decline in mean CBF. Patients with aphasia showed a significant reduction in mean CBF compared with those without aphasia. Impaired consciousness was proportional to reduction in mean CBF regardless of types of pathology, and the size of lesion did not influence the mean CBF. Patients with dementia showed a significant reduction in mean CBF proportional to the severity of dementia. The quantitative measurement of CBF using 99mTc-HMPAO SPET is reliable in clinical evaluations.

The contributions of reactive oxygen intermediates and reactive nitrogen intermediates to listericidal mechanisms differ in macrophages activated pre- and postinfection

The contribution of reactive oxygen intermediates (ROI) and reactive nitrogen intermediates (RNI) to the killing of Listeria monocytogenes by macrophages activated by addition of spleen cells from listeria-immune mice plus specific antigen was examined. When macrophages were infected with L. monocytogenes and then spleen cells were added, there was not as big a difference in listericidal activity between macrophages cultured with normal spleen cells and those cultured with immune spleen cells as expected. In this culture system, RNI was mainly involved in the macrophage intracellular killing. In macrophages first activated and then infected, a significant level of enhanced killing was observed. Blockade of ROI production drastically affected the enhanced killing ability, while inhibition of RNI production had a negligible effect. Thus, the contributions of ROI and RNI to listericidal mechanisms of macrophages were different between macrophages activated at pre- and postinfection stages.

A follow up study of myocardial involvement in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)

OBJECTIVE

To investigate cardiac function in patients with mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) and clarify the clinical features of cardiomyopathy in MELAS.

PATIENTS

11 consecutive patients with MELAS (mean age at initial examination 11.3 years, range 4 to 16 years) were enrolled in the study. Six were followed for more than five years.

RESULTS

On echocardiographic examination, three patients showed increased left ventricular end diastolic posterior wall thickness (LVPWTd), exceeding 140% of the normal value. Four patients, including these three, had an ejection fraction of less than 50%, and two also had increased left ventricular end diastolic volume (LVEDV) exceeding 140% of the normal value (%N). The LVPWTd%N was correlated positively with the LVEDV%N (R = 0.669, p < 0.05) and negatively with the ejection fraction (R = -0.6701, p < 0.05). One patient died of heart failure aged 22 years.

CONCLUSIONS

The cardiomyopathy in MELAS is characterised by an abnormally thick left ventricular wall with progressive dilatation and poor left ventricular contraction developing over several years, indicating hypertrophic cardiomyopathy advancing to dilated cardiomyopathy.

Administration of killed bacteria together with listeriolysin O induces protective immunity against Listeria monocytogenes in mice

It is known that only listeriolysin O (LLO)-producing Listeria monocytogenes strains are able to induce protective immunity, but the underlining relationship between LLO produced by virulent strains and generation of protective immunity in the infected host remains poorly understood. In the present study, it was found that LLO gene expression was only detected in the mice infected with virulent strain which was able to induce protective immunity, while non-virulent strains or killed bacteria were not able to generate protective immunity. When mice were immunized with LLO plus killed bacteria in the presence of incomplete Freund's adjuvant, the protective immunity was partially generated, and adoptive transfer experiment confirmed that this protection was antigen specific. Reverse-transcription polymerase chain reaction revealed that LLO plus killed bacteria induced the expression of interferon-gamma (IFN-gamma) and interleukin-12 (IL-12). Our results also showed CD4+ T cells were the principal cells constituting protective immunity. Taken together, it may be concluded that LLO produced from virulent strains of L. monocytogenes was essential for the generation of protective immunity, and that LLO plus killed bacteria induced IFN-gamma and IL-12 expression which resulted in the generation of protective immunity.

Progression to moderate or severe mitral regurgitation after percutaneous transvenous mitral commissurotomy using stepwise inflation technique

Progression to moderate or severe mitral regurgitation (MR) was studied after Inoue balloon percutaneous transvenous mitral commissurotomy (PTMC) using the stepwise inflation technique, performed at increments of 1 mm of balloon diameter, in 49 consecutive patients with rheumatic mitral stenosis (aged from 32-73 years; 8 males, 41 females). The patients were classified on the basis of the degree of MR after PTMC, compared with that before PTMC, into either Group A, development of moderate or more severe (> or = grade 2) MR (n = 8) or Group B, no increase in MR or development of mild (grade 1) MR (n = 41). Progression to moderate or severe MR was significantly associated only with advanced age (60 +/- 8 vs 52 +/- 10 years, p < 0.05) and narrower mitral valve area (0.87 +/- 0.35 vs 1.11 +/- 0.29 cm2, p < 0.05), but other characteristics before PTMC were similar in both groups. There was no difference between the two groups in the total number and degree of balloon inflation. Immediately before the final inflation, the left atrial mean pressure and v wave pressure were decreased in smaller degrees in Group A compared with Group B (-2 +/- 2 vs -5 +/- 4 mmHg, p < 0.05; -2 +/- 2 vs -6 +/- 6 mmHg, p < 0.05, respectively). Thus, the stepwise inflations require careful monitoring of changes in the left atrial pressure and waveform to recognize the aggravation of MR, especially in older patients with severe stenosis. Patients who do not have a significant drop in left atrial mean pressure and v wave pressure during stepwise inflations of the balloon might be at risk of development of moderate or severe MR after further dilations.

Killing mechanism of Listeria monocytogenes in activated macrophages as determined by an improved assay system

Exposure of Listeria monocytogenes to gentamicin 5 mg/L for 4 h resulted in the killing of most extracellular bacteria, but had no effect on the survival of bacteria inside macrophages. Higher concentrations of gentamicin caused a reduction in the number of intracellular bacteria. This effect was associated with cellular uptake of gentamicin, but was unaffected by activation of macrophages by interferon-gamma and lipopolysaccharide. In experiments in which exposure to gentamicin 5 mg/L for 4 h was used to kill extracellular bacteria, killing by activated macrophages was impaired when O2- production was inhibited by superoxide dismutase, but not when nitric oxide production was blocked by NG-monomethyl-L-arginine. These data suggest that the reactive oxygen intermediates are more important than nitric oxide in the killing of L. monocytogenes, at least in macrophages activated in vitro.

Reentrant ventricular tachycardia. Interpretations of electrophysiologic findings and its applications

Monomorphic sustained ventricular tachycardia (MSVT) was revisited in relation to the electrophysiologic findings and their relation to the drug efficacy. Old myocardial infarction is less common cause of MSVT in Japan, and the majority (about 2/3) of MSVT is unrelated to coronary artery disease but, the mechanism shared a common mechanism: reentry with an excitable gap as others. The reentrant mechanism was supported from the inducibility, the terminability of VT by electrical stimulation, and by the ability to entrain with rapid pacing. In MSVT associated with underlying heart diseases, diseased myocardium showed low amplitude and fragmented electrograms and the area was considered to participate as the central common pathway of reentrant circuit. The area of slow pathway showed a decremental conduction or all-or-nothing conductive property. The width of the excitable gap seemed to be determined by the maximal conductive frequency but not by the duration of action potential: effective refractory period. As to the drug efficacy, there was no baseline characteristics in predicting the efficacy. However, the significant narrowing of the width of the excitable gap was associated with the drug efficacy and VT became non-inducible after addition of the same drug. The response pattern of the excitable gap to specific drug including class III, was not predictable. Further electropharmacological studies will be warranted.

Involvement of 26-kDa membrane-bound tumour necrosis factor precursor in bidirectional feedback regulation on 17-kDa tumour necrosis factor production after stimulation by lipopolysaccharide

The authors have previously shown that 26-kDa membrane-bound tumour necrosis factor precursor (proTNF) on the cell-surface of primed human monocytic cell line THP-1 is involved in positive feedback regulation of lipopolysaccharide (LPS)-dependent TNF-production. Here, we provide direct evidence for modulation of responsiveness of the THP-1 cells against LPS by membrane-bound pro-TNF. When THP-1 cells were cocultivated with a heterogeneous cell line (proTNF/3T3 cells) which constitutively expressed membrane-bound proTNF, LPS-dependent TNF-production by THP-1 cells was significantly suppressed and the normal level was restored by the presence of anti-TNF antibody during cocultivation. The proTNF-3T3-induced decline of TNF-production of THP-1 was observed primarily at the mRNA level, although no difference was observed in the mRNA level of interleukin 1 beta, another LPS-inducible cytokine. These results suggest that proTNF could also be involved in the negative feedback regulation of LPS-dependent TNF-production through cell-to-cell contact. The augmentation of LPS-dependent TNF-production accompanied by the production of endogenous proTNF induced by exogenous agent was inhibited by protein kinase C inhibitor, whereas proTNF/3T3-induced suppression of TNF-production could not be restored to the normal level. It thus seems possible that proTNF might act on macrophages as a bidirectional regulator of its production by THP-1 cells depending on co-induced signals.

Adolescent case of Alexander disease: MR imaging and MR spectroscopy

A 17-year-old male was diagnosed as having Alexander disease from the clinical manifestations (psychomotor deterioration and megalencephaly), neuroradiologic findings (frontal dominant leukodystrophy), and elevation of alpha B-crystallin and heat shock protein 27 in the cerebrospinal fluid. He exhibited increased attenuation on computed tomography and T1 and T2 shortening on magnetic resonance imaging in the bilateral basal ganglia and thalamus. Some paramagnetic substances might be deposited in the basal ganglia and thalamus in the late stage of Alexander disease, at least 8 years after onset.

Antihypertensive effect of all-cis-5,8,11,14,17-icosapentaenoate of aged rats is associated with an increase in the release of ATP from the caudal artery

Fish oils have been shown to lower blood pressure in hypertensive subjects. All-cis-5,8,11,14,17-icosapentaenoate (EPA), one of the omega-3 polyunsaturated fatty acids, is known to be one of the major active components in fish oil that has beneficial effects on the cardiovascular system. However, little is known about the antihypertensive effect of EPA alone on blood pressure. In the present study, we have determined the spontaneous and noradrenaline-evoked release of ATP, ADP, AMP, and adenosine from caudal arteries of aged (100 weeks old) Wistar rats which were fed a standard diet or a high cholesterol diet, treated with EPA. Dietary EPA administration increased plasma and caudal arterial EPA concentrations and repressed increases in blood pressure with advancing age in both aged rats with and without hypercholesterolemia. In addition, noradrenaline (1 micromol/l) evoked a significantly greater release of purines from the caudal arteries of EPA-administered aged rats compared to both sets of control rats. Regression analysis revealed a significant relationship between the total amount of purines released from the artery and blood pressure. These results suggest that administration of EPA to aged rats increases the release of ATP from the vascular endothelial cells, leading to repression of the blood pressure rise seen with advancing age.

Procainamide induced change of the width of the zone of entrainment and its relation to the inducibility of reentrant ventricular tachycardia

Procainamide depresses conduction velocity and prolongs refractoriness in myocardium responsible for reentrant VT, but the mechanism by which the induction of VT is suppressed after procainamide administration remains to be determined. In the present study, the relationship between electrophysiological parameters and the noninducibility of VT was assessed during procainamide therapy with a special reference to the change of an excitable gap. Clinically documented monomorphic sustained VT was induced in 30 patients and, utilizing the phenomenon of transient entrainment, the zone of entrainment was measured as the difference between the cycle length of VT and the longest paced cycle length interrupting VT (block cycle length) which was determined as the paced cycle length decreased in steps of 10 ms, and used as an index of the excitable gap. The effective refractory period was measured at the pacing site and the paced QRS duration was used as an index of the global conduction time in the ventricle. The cycle length of VT, the block cycle length, and the width of the zone of entrainment were determined and compared between the responders and nonresponders. In 15 patients, these parameters were determined at the intermediate dose and related to subsequent noninducibility at the final dose. At the final doses of procainamide, VT was suppressed in 8 (26.7%) of 30 patients. However, the cycle length of VT, the block cycle length, and the width of the zone of entrainment were unable to predict the drug efficacy, i.e., noninducibility. The change in the effective refractory period at the pacing site or the width of the paced QRS duration was not different between the responders and nonresponders. Among the variables, only the width of the zone of entrainment showed a significant narrowing in the responders at the intermediate dose of procainamide, and it was smaller than that of the nonresponders. The significant narrowing of the width of the zone of entrainment was associated with the subsequent noninducibility of VT at the final dose. The present study showed that the baseline cycle length of VT, the block cycle length, the drug induced change of the effective refractory period, or the paced QRS duration was not a predictor of the noninducibility after procainamide administration. However, a significant narrowing of the width of the zone of entrainment at the intermediate dose was associated with the noninducibility of VT at the final dose.

Three-dimensional computed tomography imaging of a frontal skull base fracture

A 7-year-old boy presented with recurrent meningitis after head trauma. Coronal computed tomography (CT) revealed prolapse of the intracranial soft tissue into the right ethmoidal sinus, leading to the diagnosis of right frontal skull base fracture. Three-dimensional CT with bone windows provided a lifelike image of the fracture lateral to the right olfactory groove. This image was most useful in the preoperative planning of the repair surgery.

Stretch-induced contraction of rabbit isolated pulmonary artery and the involvement of endothelium-derived thromboxane A2

1. The mechanism of stretch-induced contraction of the intrapulmonary artery of rabbit was studied with special regard to the endothelium-dependence and production of prostanoids. 2. Isolated intrapulmonary artery of rabbits in ring form produced contraction when stretched slowly up to 180% of its initial muscle length (= 100%) at a rate of 0.44 mm s-1, with a stimulus period of 5 min. 3. The stretch-induced contraction was attenuated by the mechanical removal of the endothelium, inhibitors of cyclo-oxygenase such as aspirin and indomethacin, [1S-[1 alpha,2 alpha (Z),3 alpha,4 alpha]]-7-[3-[[2-[(phenylamino)carbonyl] hydrazino]methyl]-7-oxabicyclo[2.2.1]hept-2-y1]-5-heptenoic acid (SQ 29,548), which is a thromboxane A2/prostaglandin H2 receptor antagonist, or by ozagrel, an inhibitor of thromboxane A2 synthase. 4. Biochemical assay indicated that the production of thromboxane B2, a stable metabolite of thromboxane A2, was increased 17 times in response to stretch only when the endothelium was intact. The production of thromboxane B2 was also inhibited by aspirin or ozagrel. 5. The production of 6-keto prostaglandin F1 alpha, a stable metabolite of prostacyclin, was also increased in response to stretch in the preparation with intact endothelium. However, ozagrel showed no apparent effect on the production of 6-keto prostaglandin F1 alpha. 6. These results suggest that a mechanical stimulus like stretch can act on endothelial cells of rabbit pulmonary artery to cause contraction by activation of arachidonic acid metabolism via the cyclooxygenase pathway and subsequent release of thromboxane A2 and/or an increase in the ratio of thromboxane A2/prostacyclin.

Extensive interbreeding occurred among multiple matriarchal ancestors during the domestication of dogs: evidence from inter- and intraspecies polymorphisms in the D-loop region of mitochondrial DNA between dogs and wolves

To test the hypothesis that the domestic dogs are derived from several different ancestral gray wolf populations, we compared the sequence of the displacement (D)-loop region of the mitochondrial DNA (mtDNA) from 24 breeds of domestic dog (34 individual dogs) and 3 subspecies of gray wolf (Canis lupus lupus, C.l. pallipes and C.l. chanco; 19 individuals). The intraspecific sequence variations within domestic dogs (0.00-3.19%) and within wolves (0.00-2.88%) were comparable to the interspecific variations between domestic dogs and wolves (0.30-3.35%). A repetitive sequence with repeat units (TACACGTA/GCG) that causes the size variation in the D-loop region was also found in both dogs and wolves. However, no nucleotide substitutions or repetitive arrays were specific for domestic dogs or for wolves. These results showed that there is a close genetic relationship between dogs and wolves. Two major clades appeared in the phylogenetic trees constructed by neighbor-joining and by the maximum parsimony method; one clade containing Chinese wolf (C.l. chanco) showed extensive variations while the other showed only slight variation. This showed that there were two major genetic components both in domestic dogs and in wolves. However, neither clades nor haplotypes specific for any dog breed were observed, whereas subspecies-specific clades were found in Asiatic wolves. These results suggested that the extant breeds of domestic dogs have maintained a large degree of mtDNA polymorphisms introduced from their ancestral wolf populations, and that extensive interbreedings had occurred among multiple matriarchal origins.

Specific attenuation of the pressure-induced contraction of rat cerebral artery by herbimycin A

In order to determine whether protein tyrosine kinase mechanisms are involved in pressure-induced contraction, we compared effects of three structurally unrelated tyrosine kinase inhibitors and orthovanadate, a tyrosine phosphatase inhibitor, on the pressure-induced contraction of the posterior cerebral artery isolated from rats. The change in vessel diameter was continuously measured with a width analyzer. Herbimycin A inhibited the pressure-induced contraction, while it only slightly inhibited contractions produced by potassium chloride or 9,11-dideoxy-11alpha,9alpha-epoxymethano prostaglandin F2alpha (U46619). Genistein inhibited not only the pressure-induced contraction but also the U46619-induced one. Tyrphostin 23 significantly attenuated contractions in response to three different stimuli, i.e., pressure, potassium chloride and U46619. Orthovanadate potentiated the pressure-induced contraction. These results suggest that herbimycin A is a specific and potent inhibitor of the pressure-induced contraction and that a protein tyrosine kinase mechanism may play an important role in the genesis of the pressure-induced contraction of the rat cerebral artery.