Search PubMed⌕ Search

Biomedical subjects

H Naito

Publications and source records attributed to H Naito.

At least 163 records · Page 9Linked to original sources
PubMed1996

[Pylorus-preserving gastrectomy for early gastric cancer].

Pylorus-preserving gastrectomy (PPG) was originally proposed by Maki et al for gastric ulcer. Recently this operation with lymph node dissection has been adopted for patients with early gastric cancer locating at antrum and body of the stomach in Japan. But standard procedure of this operation has not been established yet. Grade of lymph node dissection, preservation of pyloric branch and indication criteria are fairly dependent on each surgeon when PPG is applied for gastric cancer. Although the results of this operation is not accumulated enough, it is considered that this operation may have benefits for decrease of postoperative chronic morbidity with acceptable cancer curativity as compared to conventional distal gastrectomy, Billroth-I procedure.

Gastrectomy↗
PubMed1996

Modified procedure with a surgical stapler for construction of a Pavlov pouch in dogs.

An aim of this study was to establish a simple method for the construction of a Pavlov pouch that is free of fistula formation between the main part of the stomach and the pouch, yet preserves maximal vagal innervation. The Pavlov pouch (vagally innervated gastric pouch) was constructed from the greater curvature of the gastric corpus at the level of the splenic hilus in four dogs. The plane between the mucosal and seromuscular layers was dissected bluntly along the medial margin of the pouch. A surgical stapler was introduced into the space between the mucosal and seromuscular layers, and the pouch was completely separated from the main part of the stomach enterically at the mucosal level but remained connected via the seromuscular layers. All dogs survived the operation and lost minimal weight; fistulas were not found between the remnant stomach and the pouch at necropsy 6 to 8 weeks later. Gastric acid secretion for 30 to 90 min after insulin-induced hypoglycemia, which increases vagal tone, was significantly increased compared to that before insulin injection, confirming preservation of vagal innervation to the pouch. Our technique to create a Pavlov pouch is superior to the methods reported previously because of its simplicity, lower prevalence of fistula formation, and reliable preservation of vagal innervation to the pouch.

Animals↗
PubMed1996

[Verification of accuracy of several algorithms to quantitate left ventricular regional wall motion: a study using cine MR imaging with myocardial tagging].

To verify the accuracy of several algorithms used to quantitate left ventricular (LV) regional wall motion, five volunteers were examined by cine MR imaging with presaturation myocardial tagging in short-axis and 4-chamber sections. Three algorithms for the wall motion analysis, radial, centerline, and originally developed "modified-Hildreth" methods, were applied to the cine MR images, and dissociation of the end-systolic position of the tags estimated by each algorithm from the true position was examined. The modified-Hildreth method was comparable in accuracy to the other methods for estimating end-systolic tag position. Significantly worse estimation of the tag position by the three algorithms occurred in the 4-chamber section compared with the short-axis section (p < 0.001, 0.005), indicating difficulties in the wall motion analysis of "long-axis" LV images. Among the algorithms, the centerline method showed the highest accuracy of the estimation in the 4-chamber section, and the modified-Hildreth method was the best in the short-axis section. In the 4-chamber section, correction of the position of end-diastolic and end-systolic images around the luminal centroids improved the estimation (p < 0.01, 0.05). Tagging cine MR imaging was proved to be useful for determining the most suitable algorithm for quantitative wall motion analysis of LV images obtained from conventional angiocardiography and other imaging modalities.

Adult↗
PubMed1995

Frequent mutations of Ki-ras codon 12 in N-bis (2-hydroxypropyl)-nitrosamine-initiated thyroid, kidney and lung tumors in Wistar rats.

N-Bis (2-hydroxypropyl) nitrosamine (DHPN) is a very potent mutagen and wide spectrum carcinogen in rodents. In the present study, we investigated mutational activation of the Ki-ras gene in eight thyroid, five kidney (four mesenchymal and one transitional cell lesion) and two lung tumors induced with DHPN. Mutations were identified using single-strand conformation polymorphism, restriction fragment length polymorphism and DNA sequencing analysis. All of the 15 neoplasms could be shown to have mutations in codon 12 (GGT-->GAT). These results suggest that Ki-ras mutations are frequent events during the development of DHPN-induced carcinomas in these organs. In a separate experiment, moreover, we analyzed the presence of Ki-ras mutations in various tissues 8 weeks after DHPN treatment. One of five thyroid tissues treated with DHPN was found to have the same characteristic mutation, suggesting that it may represent an early event during carcinogen-induced tumor formation in the thyroid.

Animals↗
PubMed1995

Neonatal damage to neocortex abolishes the anxiolytic action of diazepam in adult rats.

A neonatal cerebral cortical lesion was made in rats and the effects of diazepam on ultrasonic isolation calls in pups and footshock-elicited ultrasonic distress calls in young adult rats were assessed. There was no indication that the cortical lesion influenced the production of the ultrasonic distress calls in either pups or adults. Diazepam attenuated the ultrasonic isolation calls in all the pups with and without cortical lesion, and the distress calls in normal adult rats. However, diazepam failed to exert the effect in rats which received a neonatal cortical lesion. 8-Hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), another anxiolytic, was effective to diminish the distress calls even in the adult rats which had had the neonatal damage to the cortex. These findings indicate that the intact cerebral cortex is not always required for production of ultrasonic distress calls; however, the development of the neuronal mechanism involving benzodiazepine receptors to inhibit the ultrasonic expression of anxiety or fear in adult rats is dependent on the integrity of the cerebral cortex.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1995

Haemodynamic, diuretic and hormonal responses to prostaglandin E1 infusion in halothane anaesthetized dogs: comparison among epidural lidocaine, epidural fentanyl and epidural saline.

Deliberate hypotension decreases blood loss and transfusion but it may be accompanied by adverse effects due either to the hypotensive agents themselves or to haemodynamic alterations. Prostaglandin E1 (PGE1) has the advantage of a diuretic effect coupled with systemic hypotension. To elucidate the mechanisms by which PGE1 induces diuresis we compared the haemodynamic, diuretic and hormonal responses to PGE1 infusion simultaneously with epidural lidocaine (EP-L n = 7), epidural fentanyl (EP-F n = 8) or epidural saline (CONT n = 7) in halothane anaesthetized mongrel dogs. All groups developed a decrease in mean arterial pressure during PGE1 infusion (from 105 +/- 24 to 77 +/- 18 mmHg in EP-L; 106 +/- 19 to 79 +/- 13 mmHg in the EP-F; and 129 +/- 14 to 106 +/- 18 mmHg in the CONT groups (mean +/- SD)) (P < 0.05). In the EP-F and CONT groups urinary output increased during PGE1 infusion (from 4.31 +/- 1.89 to 6.15 +/- 2.03 ml.min-1 and 2.71 +/- 1.23 to 4.48 +/- 1.66 ml.min-1 (P < 0.05), respectively) and was accompanied by increases in renal blood flow (from 87.0 +/- 40.7 to 111.0 +/- 42.8 ml.min-1 and from 121.6 +/- 46.6 to 158.4 +/- 64.9 ml.min-1 (P < 0.05), respectively) and in fractional excretion of sodium (FENa) (from 4.78 +/- 3.88 to 7.63 +/- 5.20% in CONT group).(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1995

Intragastric capsaicin stimulates colonic motility via a neural reflex in conscious dogs.

BACKGROUND & AIMS: Capsaicin is known to contract smooth muscles and to have an excitatory action on thin, primary afferent neurons. The aim of this study was to test the hypothesis that intragastric capsaicin may have an excitatory effect on colonic motility. METHODS: Mongrel dogs equipped with five strain-gauge force transducers on the colon (C1-C5) were used. In 5 dogs, the effect of intragastric capsaicin (0.05, 0.1, 0.3, and 0.5 mg/kg) on colonic motility in the presence or absence of the cholinergic blockers atropine and hexamethonium was studied. In 4 dogs, the effect of capsaicin (0.5 mg/kg) administration into a vagally innervated or denervated gastric pouch on colonic motility was investigated. RESULTS: Motility at C2-C3, C1-C3, and C1-C5 was significantly increased by 0.1, 0.3, and 0.5 mg/kg of capsaicin, respectively. The excitatory effect of capsaicin on colonic motility was inhibited by atropine and hexamethonium. Colonic motility at C1-C4 was significantly increased by capsaicin administration into a vagally innervated pouch but was not affected by capsaicin administration into a vagally denervated pouch. CONCLUSIONS: These results indicate that intragastric capsaicin predominantly stimulates motility in the proximal half of the colon through neural pathways, probably through a vagovagal reflex, but sympathetic involvement cannot be excluded.

Animals↗
PubMed1995

Failure to detect dopaminergic neuroblastoma in a mass-screening system.

Dopaminergic neuroblastoma comprised 12% of the patients under 1 year of age, and 83% of the older ones. Seven cases were missed by the mass-screening system performed at age 6 months and were detected after 16 months. Three of these advanced cases were positive only for dopamine. These findings supports our second mass-screening system using dopamine evaluation at age 14 months.

Age Factors↗
PubMed1995

The comparison of epidural fentanyl, epidural lidocaine, and intravenous fentanyl in patients undergoing gastrectomy.

This study was conducted prospectively to compare the effect of epidural fentanyl (EP-F), epidural lidocaine (EP-L), and intravenous fentanyl (IV-F) on hemodynamic and hormonal responses to surgery and postoperative analgesic requirement in 30 patients undergoing gastrectomy during isoflurane anesthesia. An epidural catheter was placed via the T8-9 interspace. Group EP-F received fentanyl 2 micrograms/kg in 10 mL saline, and Group EP-L, 10 mL 1.5% lidocaine, epidurally; Group IV-F was given fentanyl, 2 micrograms/kg, IV. Fifty percent of the original dose was repeated every hour. Hemodynamic data and plasma hormonal levels were compared between those before and those at 1 h after skin incision. The total number of analgesic administrations within the first 48 h postoperatively were compared. Group EP-L developed more frequent episodes of hypotension. Group IV-F required higher isoflurane concentrations and the plasma epinephrine levels increased more than in Groups EP-F and EP-L. In Groups EP-L and IV-F, the plasma antidiuretic hormone (ADH) level increased more than in Group EP-F. In Groups EP-F and IV-F, the plasma cortisol and adrenocorticotropic hormone (ACTH) levels increased more than in Group EP-L. The use of postoperative analgesics was significantly less in Group EP-F. In conclusion, in Group EP-F, attenuated hormonal responses to surgery was accompanied with less hypotension and postoperative analgesic requirements were reduced.

Adjuvants, Anesthesia↗
PubMed1995

Significance of dipyridamole loading in ultrafast x-ray computed tomography for detection of myocardial ischemia. A study in patients with Kawasaki disease.

BACKGROUND AND RATIONALE: To examine the significance of dipyridamole loading as a stress in ultrafast computed tomography (CT) to improve the detection of left ventricular myocardial ischemia. METHODS: Thirty-eight patients with coronary arterial involvement of Kawasaki disease and 18 control subjects received cardiac ultrafast CT with intravenous long-bolus iodinated contrast injection; dipyridamole was loaded in 40 examinations. Early (first-pass) and late (4 minutes) M/Ls (ratio of postcontrast incremental increases in the left ventricular myocardial [M] and luminal [L] CT number) were analyzed. RESULTS: Dipyridamole induced a prominent increase in early M/L of the normal myocardium in control subjects (no loading: 26.8%, dipyridamole: 39.2%; P < 0.001) with small influence on late M/Ls. In ischemic or infarcted myocardium in Kawasaki disease, dipyridamole early M/Ls (20.4%, 16.0%) and late M/Ls showed no difference from corresponding values without loading. Using early M/L with dipyridamole, sensitivity and specificity for detection of ischemic abnormalities were 89% and 100%, respectively. CONCLUSIONS: Dipyridamole-loaded first-pass contrast ultrafast CT was proven to have excellent detectability for myocardial ischemia comparable with stress thallium scintigraphy.

Adolescent↗
PubMed1995

Spinal anesthesia attenuates myocardial ischemia during coronary artery spasm induced by intraaortic methacholine in rats.

Coronary artery spasm is not rare in patients with coronary artery disease, but the influence of regional anesthesia on spasm-induced myocardial ischemia is not known. We investigated the effects of spinal anesthesia on myocardial ischemia during coronary artery spasm in rats, and compared these with the effects of an alpha- and beta-adrenergic antagonist, and an alpha-adrenergic agonist. An intraaortic catheter was inserted via the right internal carotid artery so that the tip of the catheter was placed near the coronary ostium. An intrathecal catheter was placed at lumbar level. Coronary spasm was induced by the intraaortic injection of methacholine, and we identified the thresholds of myocardial ischemia, defined as the dose of methacholine that induced ST-segment elevation. Subsequently, the thresholds were determined after spinal anesthesia, and after the intraaortic injection of phentolamine and propranolol. The thresholds of myocardial ischemia increased significantly after intrathecal bupivacaine. In contrast, the threshold did not change after the injection of phentolamine. The thresholds increased significantly after the injection of propranolol. Methoxamine significantly decreased the threshold of ischemia. These results demonstrated that spinal anesthesia attenuated myocardial ischemia during methacholine-induced coronary spasm. This effect was equivalent to that of propranolol.

Adrenergic alpha-Agonists↗
PubMed1995

Assessment of right ventricular regional contraction and comparison with the left ventricle in normal humans: a cine magnetic resonance study with presaturation myocardial tagging.

OBJECTIVE: Right ventricular regional contractility has been thought to be difficult to assess precisely. Cine magnetic resonance imaging with presaturation myocardial tagging was employed to quantitate the contraction of the right ventricular free wall and to identify normal performance compared with the left ventricle. METHODS: Nine normal volunteers, aged 27-39 years, were examined in a 1.5 Tesla superconductive magnet, and short axis and four-chamber sections at the mid-ventricular level were imaged with cine magnetic resonance sequences. Tags, applied at end diastole as two parallel black lines, intersected the mid-portion of the free wall, dividing it into upper, centre, and lower segments in the short axis section, and anterior, middle, and posterior segments in the four-chamber section. From a series of cine magnetic resonance images at 50 ms intervals over a cardiac cycle, end diastolic, and early, mid-, and end systolic images were chosen for calculation of the endocardial, epicardial, and mean percent fractional shortening (%FS) in the six segments. RESULTS: There was (1) a gradual increase in %FS in systole in both sections (P < 0.001, < 0.005); (2) a poor transmural gradient of contractility; (3) a predominance of meridional shortening (whole length, mean end systolic %FS (SD): short axis, 17.4 (3.1)%; four-chamber, 30.1 (4.1)%; P < 0.001) in contrast to dominant circumferential shortening in the left ventricular lateral wall; (4) lower predominance of contractility in the short axis section (P < 0.001), and a middle dip of contractility in the four-chamber section (P < 0.005). CONCLUSIONS: Heterogeneity of contractility was closely correlated with the myocardial fibre architecture, and with wall stress determined by its thickness and curvature. It was proved that right ventricular regional function could be analysed non-invasively using cine magnetic resonance imaging with myocardial tagging.

Adult↗
PubMed1995

Fractal analysis of interstitial lung abnormalities in chest radiography.

A computerized method for analyzing interstitial lung abnormalities seen on chest radiographs was investigated. The method includes two main steps: (a) extraction of linear opacities on chest radiographs and (b) calculation of the fractal dimension. Extraction of linear opacities uses the processes of four-directional Laplacian-Gaussian filtering, binarization, and linear opacity judgment. The fractal dimensions in the processed images are then calculated by using the box-counting algorithm. The accuracy of the computerized method in differentiating between normal and abnormal lung tissue was tested on digitized chest radiographs (0.175 mm pixel, 10-bit) of 100 randomly selected patients. One hundred regions of interest (ROIs) from radiographs of 50 patients with interstitial lung abnormalities and 100 ROIs from radiographs of 50 patients with normal lungs were analyzed. The fractal dimensions obtained from the ROIs in lungs with interstitial abnormalities were significantly higher compared with those from ROIs in normal lungs (mean, 1.67 +/- 0.10 vs 1.44 +/- 0.12, respectively; P < .001). This result indicates that fractal analysis is useful in distinguishing interstitial lung abnormalities from normal lung tissue on chest radiographs.

Adult↗
PubMed1995

Clinical evaluation of pulmonary nodules with single-exposure dual-energy subtraction chest radiography with an iterative noise-reduction algorithm.

PURPOSE: To compare the clinical usefulness of the single-exposure dual-energy subtraction method with an iterative noise-reduction algorithm. MATERIALS AND METHODS: Fourteen radiologists read three sets of images from 44 patients: original computed radiographic images only, original computed radiographic images plus conventional bone-subtracted images, and original computed radiographic images plus iterative noise-reduced bone-subtracted images. Twenty-two patients had one or more (maximum, five) pulmonary nodules; 22 had no pulmonary nodules. Observer performance was evaluated by means of calculation of the average area under the alternative free-response receiver operating characteristic curves (A1). RESULTS: Compared with the original computed radiographic image only, detection of nodules was significantly better with both the original computed radiographic image plus iterative bone-subtracted image (A1 = 0.72 +/- 0.02 and 0.66 +/- 0.02, respectively; P = .01) and the original computed radiographic image plus conventional bone-subtracted image (A1 = 0.66 +/- 0.02 and 0.61 +/- 0.01, respectively; P = .03). CONCLUSION: The iterative noise-reduction algorithm is superior to conventional methods in detection of pulmonary nodules.

Adolescent↗
PubMed1995

[Gastric emptying of semi-solid meal in normal man with special reference to relationship between plasma acetoaminophen concentrations and gastric emptying time].

Correlation between gastric emptying time measured by a radioisotope method and plasma acetoaminophen level was studied in 11 preoperative early gastric cancer in semisolid meal. A significant correlation was found between both gastric emptying half-time and plasma acetoaminophen level at 30, 45 minutes after ingestion of meal, and plasma acetoaminophen level at maximum. We conclude that acetoaminophen analysis is useful to measure gastric emptying at semisolid meal.

Acetaminophen↗
PubMed1995

Gastric mucosal phosphatidylcholine hydroperoxide increases during cold water-immersion restraint stress in rats.

To know the role of lipid peroxidation in the pathogenesis of stress-induced gastric mucosal lesions, we performed the present study. Both gastric mucosal lesions and gastric mucosal phosphatidylcholine hydroperoxides (PCOOH) levels during cold water-immersion restraint (CWIR) stress were measured by the chemiluminecence-HPLC method in Sprague-Dawley rats. Ulcer indices increased time-dependently during the stress. Gastric mucosal PCOOH levels also significantly increased and reached a peak level (250% of untreated level) after 2 hr of stress. These results suggest that lipid peroxidation may play an important role in the pathogenesis of gastric mucosal lesions induced CWIR stress.

Animals↗