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Biomedical subjects

N Tomiyama

Publications and source records attributed to N Tomiyama.

At least 55 records · Page 3Linked to original sources
PubMed1994

High-resolution CT and pulmonary function tests in collagen vascular disease: comparison with idiopathic pulmonary fibrosis.

To estimate whether the lung abnormalities seen in collagen vascular diseases (CVD) were similar or distinct to those seen in idiopathic pulmonary fibrosis (IPF), and to ascertain whether the extent of the abnormalities on high-resolution CT (HRCT) correlated with pulmonary function, we reviewed HRCT findings and pulmonary function test results of 64 patients with either CVD (n = 55) or IPF (n = 9). Response to corticosteroid treatment was also evaluated in 20 of the 64. High incidence of honeycomb lesion was observed in IPF (9/9, 100%) and in progressive systemic sclerosis (PSS) (11/14, 79%). CVD, except for PSS, had a low incidence of honeycomb lesion (27%). On the other hand, incidence of ground-glass shadow in CVD (47/55, 85%) was the same as that in IPF (8/9, 89%). Diffusing capacity significantly correlated with the extent of all parenchymal abnormalities in all CVD and IPF, with honeycomb lesion in PSS, and with ground-glass shadow or air-space consolidation in CVD except for PSS (r < -0.7, P < 0.001). In all 15 cases in which corticosteroid therapy was effective, no honeycomb lesions were seen. Collagen vascular disease, except for PSS, had a different pattern of disease than IPF. The morphologic changes seen on HRCT correlated well with pulmonary function in CVD.

Collagen Diseases↗
PubMed1994

Interpretation of subtle interstitial lung abnormalities: conventional versus film-digitized radiography.

PURPOSE: To evaluate the reliability of film-digitized radiography in detection of subtle interstitial lung abnormalities. MATERIALS AND METHODS: The differences in interpretation of conventional screen-film (SF) and film-digitized (FD) radiographs obtained in 80 patients were studied. Forty patients with subtle interstitial lung abnormalities and 40 patients with no lung abnormalities were selected. SF radiographs of all patients were digitized (spatial resolution, 0.175 mm; 2,000 x 2,000 pixels; 10 bits). Five chest radiologists and five residents evaluated the images with a five-level scale of confidence. Results were evaluated with receiver operating characteristic techniques. RESULTS: For the entire group, no statistically significant differences in performance were found between SF and FD radiographs. Chest radiologists performed better on SF radiographs (P = .003). For residents, no statistically significant differences were observed between the modalities. CONCLUSION: FD radiographs may be inadequate compared with SF radiographs in the diagnosis of subtle interstitial lung abnormalities.

Adult↗
PubMed1994

Neurons with high-frequency discharge in the central nervous system in chronic pain.

Prior to implantation of the thalamic- or motor cortex-stimulating electrodes for relieving chronic pain, extracellular unitary activity was recorded and local microstimulation was done, by using microelectrodes, mainly in the ventral caudal nucleus of the thalamus. A significant number of high frequency discharge neurons (hyperactive neurons) were recorded and showed three types of discharge patterns with different interval histograms. In animal experiments, unilateral dorsal root sectioning from C5 to Th1 of male Wistar rats was made according to the method of Lombard et al[4]. One to three months after the operation, cellular activity was recorded from the contralateral thalamic nuclei (VP, zona incerta), lemniscus medialis and striatum. Hyperactive neurons were recorded from the thalamic nuclei and lemniscus medialis. The firing patterns and distribution of hyperactive neurons in these animals were very similar to those of humans. Hyperactive neurons were examined via electrical stimulation of and/or iontophoretical application of chemical substances. Hyperactive neurons were unaffected by electrical stimulation of the nucleus raphe dorsalis and locus ceruleus. However, sensorimotor cortical stimulation showed a reduction of firing in the hyperactive neurons. Iontophoretic application of glutamate showed increase in firing and GABA showed remarkable firing suppression. These results suggested that hyperactive neurons of the thalamic nuclei receive a facilitatory effect from the sensorimotor cortex with little influence from adrenergic or serotonergic systems, and these neurons have a relationship to the glutamatergic and GABAergic fibers or receptors.

Action Potentials↗
PubMed1994

[Sequential change of cerebral angiography in a case of cerebral angiitis following herpes zoster ophthalmicus].

Delayed neurological symptoms and signs following herpes zoster ophthalmicus (HZO) such as "Delayed contralateral hemiplegia with HZO" are supposed to be due to ipsilateral intracranial angiitis and ischemic disorder. We experienced a rare case with ipsilateral cerebral hemorrhage following HZO. Under the diagnosis of cerebral angiitis associated with HZO, we treated her conservatively and observed sequential change of angiography for four months. A 54-year-old female, who had been treated for systemic lupus erythematosus (SLE), developed HZO on left ophthalmic nerve area. Seven weeks after the onset of HZO, she complained of headache, mild right hemiparesis, and disturbance of consciousness. Computed tomography revealed subcortical hemorrhage at the left temporo-occipital lobe. Cerebral angiography showed vascular irregularities such as segmental narrowing and sausage-like dilation on proximal portion of the ipsilateral anterior, middle and posterior cerebral arteries. Same findings were seen on peripheral portions of the posterior cerebral artery on the same side. Moreover sequential angiograms showed appearance of an aneurysm in the left middle cerebral artery (M2 potion). Under the diagnosis of cerebral angiitis associated with HZO, she was treated with antiviral agents, antiplatelet drugs, steroid and stellate ganglion block. Those irregularities were found to diminish on the sequential angiograms, and the aneurysm disappeared four month later.

Cerebral Angiography↗
PubMed1993

Interpretation of subtle interstitial lung abnormalities: conventional versus storage phosphor radiography.

To evaluate the reliability of storage phosphor radiography (SR) in diagnosis of subtle interstitial lung abnormalities, the differences among radiologists in interpreting conventional screen-film radiographs and full-size and minified SR images obtained in 80 patients were studied. Forty patients had subtle interstitial lung abnormalities and 40 had no lung abnormalities. Seven chest radiologists and seven residents evaluated the images by using a five-point presence of abnormality scale. Results were evaluated with receiver operating characteristic technique. For all observers, no significant differences were observed among the three image types. For the chest radiologists, significant differences were observed between conventional radiographs and the two SR formats (P < .01). Furthermore, perceptual accuracy was best with conventional radiographs evaluated by chest radiologists. Overall performance with SR and conventional radiography was identical for diagnosis of abnormalities, but detection performance was significantly dependent on observer experience (P < .01 for chest radiologists and P > .01 for residents). For chest radiologists, critically important information may be lost with commercially available SR.

Adolescent↗
PubMed1993

Focal organizing pneumonia: CT appearance.

PURPOSE: To clarify the computed tomographic (CT) features of focal organizing pneumonia. MATERIALS AND METHODS: The authors retrospectively studied CT scans of 18 patients with histologically proved focal organizing pneumonia. Chest radiographs in all 18 patients suggested bronchogenic carcinoma. RESULTS: Seventeen of the 18 lesions (94%) had an irregular margin, 10 (56%) had satellite lesions, nine (50%) had a pleural tag, and nine (50%) had an air bronchogram. The pneumonia could be classified into three types: Type A (n = 5) was a small round mass (pleural tag, n = 4). Type B (n = 7) was an oval mass with broad contact with the pleura (satellite lesions and convergence of peripheral vessels, n = 6). Type C (n = 6) was an oval mass along the bronchovascular bundle (satellite lesions, n = 3; pleural tag, n = 4). CONCLUSION: The CT features of focal organizing pneumonia show wide variation, and some type B and C lesions are suggestive of benign lesions. However, other lesions may be difficult to differentiate from bronchogenic carcinoma even with CT.

Adult↗
PubMed1993

Mechanism of gravity-dependent atelectasis. Analysis by nonradioactive xenon-enhanced dynamic computed tomography.

RATIONALE AND OBJECTIVES: The physiologic mechanism of gravity-dependent atelectasis (GDA), a common finding identified during anesthesia, is not well understood. The purpose of this study was to determine whether an inherent reduction in alveolar volume or a reduction in alveolar ventilation is the more important causative factor for the development of GDA in an experimental animal model. METHODS: After uniform reduction of lung volume in ten rabbits by artificially induced pneumoperitoneum, dynamic inhalation computed tomography (CT) was performed using 50% nonradioactive xenon in oxygen. Time-CT attenuation value curves were fitted to an exponential function, CT value = a - b x e(-kt), and K value, which is proportional to the alveolar ventilation/alveolar volume ratio, was calculated by regression analysis. RESULTS: Gravity-dependent atelectasis occurred only in 5 of 10 rabbits. In this group, K values in the dorsal regions increased before the appearance of GDA. No significant change in K values in the ventral regions was observed. CONCLUSION: One mechanism of GDA may be a preferential reduction in alveolar volume without small airway collapse rather than alveolar volume loss secondary to decreased ventilation.

Animals↗
PubMed1992

Sjogren syndrome: comparison of sialography and ultrasonography.

Ultrasonography and sialography of parotid glands were prospectively performed on 30 patients with Sjogren syndrome and follow-up ultrasonography was done on 12 patients. Ultrasonography revealed multiple hypoechoic areas (MHA) 2 mm to 5 mm in diameter within the glands in 43% of the patients with intermediate severity of the disease, either homogeneous or slightly nonhomogeneous parotid glands in patients with early stage of the disease, and marked nonhomogeneous glands in patients with advanced diseases. Follow-up ultrasonography showed MHA in one patient, reduction in nonhomogeneity in another three, and no interval changes in the remaining cases. Pathologic studies suggested that MHA represent enlarged parotid lobules replaced by lymphocytic infiltration. We suggest that MHA are characteristic of Sjogren syndrome and that ultrasonography is useful in following the course of the disease and response to treatment.

Female↗
PubMed1992

Thyroid nodules associated with Hashimoto thyroiditis: assessment with US.

Sonographic findings in 109 thyroid nodules in 104 patients with Hashimoto thyroiditis were retrospectively analyzed. Sixty patients underwent ultrasound (US)--guided fine-needle aspiration (FNA) biopsy (65 nodules, 24 palpable, 27 surgically confirmed), 14 of whom also underwent palpation-guided FNA (14 nodules, all palpable, all surgically confirmed). Forty-four patients (44 nodules, 25 palpable) underwent diagnostic US followed up with surgery. US-guided FNA helped differentiate between benign (n = 11) and malignant (n = 16) diseases (sensitivity, 100%). Two papillary carcinomas were falsely diagnosed as Hashimoto thyroiditis with palpation-guided FNA. Eight malignancies were not palpable, and correct diagnosis was obtained with US-guided FNA. Hyperechoic nodules were usually benign, and isoechoic nodules had a low frequency (13%) of malignancy. Most carcinomas were found in hypoechoic masses, and almost all lymphomas were found in markedly hypoechoic masses. Lymphoma was indistinguishable from pseudotumor in Hashimoto thyroiditis or adenomatous hyperplasia at US. US-guided FNA is helpful in making the histologic diagnosis in thyroid nodules associated with Hashimoto thyroiditis. US-guided FNA is clinically beneficial because it can help select patients who need surgery, avoiding unnecessary surgery for patients with nonneoplastic disorders.

Adenoma↗
PubMed1992

CT findings in lymphangitic carcinomatosis of the lung: correlation with histologic findings and pulmonary function tests.

The purpose of this study was to analyze the CT findings in lymphangitic carcinomatosis and to determine how the abnormalities seen on CT correlated with histologic findings and the results of pulmonary function tests. Accordingly, we reviewed CT findings in 20 proved cases and correlated them with histologic findings and with results of pulmonary function tests (available in 11). Special attention was given to the extent and degree of thickening of the peripheral and/or axial interstitium as seen on CT. In 15 of 20 patients, CT scans showed marked thickening of axial interstitium and subtle or no thickening of peripheral interstitium (four diffuse and 11 localized). In three cases, CT showed marked thickening of both axial and peripheral interstitium (two diffuse and one localized). In two cases, CT showed marked thickening of peripheral interstitium and subtle or no thickening of axial interstitium (one diffuse and one localized). These CT findings correlated with the pathologic findings. Marked impairment of vital capacity and alveolar-arterial oxygen gradient was observed in three patients (one with diffuse and peripheral interstitial thickening and two with diffuse and both peripheral and axial interstitial thickening). We conclude that CT findings in patients with lymphangitic carcinomatosis are variable and that marked impairment of pulmonary function occurs in patients with diffuse and peripheral interstitial thickening. Marked impairment of pulmonary function can be predicted from CT findings.

Adult↗
PubMed1992

CT appearance of pulmonary tuberculosis in diabetic and immunocompromised patients: comparison with patients who had no underlying disease.

OBJECTIVE: It has been stated, but not adequately assessed, that pulmonary tuberculosis in diabetic or immunocompromised patients often has an atypical pattern and distribution. To evaluate the CT features of pulmonary tuberculosis in diabetic or immunocompromised patients compared with patients without underlying disease, we performed this retrospective study. MATERIALS AND METHODS: We reviewed conventional CT scans (n = 100) and high-resolution CT scans (n = 16) of the chest in 110 adult patients with active postprimary tuberculosis. Seventy-one patients had no underlying disease, 31 had diabetes mellitus, and eight were immunocompromised. RESULTS: In patients who had no underlying disease, 44 had nodular opacities, 11 had consolidation, and 13 had consolidation with associated loss of volume. Characteristic features of tuberculosis in this group of patients included segmental distribution (97%), satellite lesions (93%), single cavity within any given lesion (95%), and tendency toward architectural distortion and loss of volume. In diabetic and immunocompromised patients, 15 had nodular opacities, seven had consolidation, and 15 had consolidation with associated loss of volume. Diabetic and immunocompromised patients had a high prevalence of nonsegmental distribution (30%) and multiple small cavities within any given lesion (44%). Unusual localization of tuberculosis, including disease confined to the basal segments of the lower lobes, anterior segment of the upper lobes, or right middle lobe, occurred equally in both groups (17% and 18%). CONCLUSION: We conclude that diabetic and immunocompromised patients have a higher prevalence of multiple cavities within any given lesion (p < .01) and of nonsegmental distribution (p < .01) than do patients without underlying disease.

Adult↗
PubMed1991

[Chest radiograph of foreign bodies in the tracheobronchial tree].

Chest radiographs in 14 children with foreign bodies in the tracheobronchial trees were evaluated retrospectively. The most common causative materials were nuts, and both main bronchi were most commonly involved. The initial chest radiographs that were used for analysis were obtained one hour to 50 days after aspiration or onset of symptoms. Of the nine cases in which chest radiographs were taken within 7 hours after aspiration, six showed hyperlucency with (three cases) or without overinflation (three cases) in the affected lungs, and the other three showed normal chest radiographs. Two patients had indeterminate diagnoses on chest radiographs at inspiration: one patient underwent chest radiographs at expiration and the other underwent fluoroscopy. Air-trapping was demonstrated in both patients. Of another five cases in which chest radiographs were taken 18 hours after aspiration of a foreign body, three cases showed atelectasis or consolidation and the other two showed hyperlucent lung. From these observations, hyperlucent lung indicates an early stage of the disorder while atelectasis or consolidation indicates a fairly advanced stage. In patients with clinically suspected foreign bodies, we advocate that additional examinations be performed to establish a final diagnosis, even when chest radiographs are normal or indeterminate.

Bronchi↗
PubMed1991

Carcinoma of the esophagus: CT vs MR imaging in determining resectability.

MR imaging and CT were performed prospectively in 35 patients with esophageal carcinoma to determine the resectability of the primary tumors, because at our institution patients with resectable tumors have surgery regardless of the presence of distant metastases. Tumors with evidence of aortic or tracheobronchial invasion on MR or CT were considered to be unresectable. Tracheobronchial invasion was diagnosed when the tumor extended into the lumen of the airway, and aortic invasion was diagnosed when the triangular fat space between the esophagus, aorta, and spine adjacent to the primary tumor was obliterated. Two patients were excluded because of suboptimal MR images produced by motion artifacts. Pathologic proof was obtained from either surgery or autopsy in 31 patients. Of these, six patients (19%) had proved unresectable tumors (three aortic invasion and three tracheobronchial invasion). In all six cases, these features were correctly detected with both MR and CT. One patient had false-positive findings on MR and CT. An indeterminate diagnosis was obtained with MR in three patients and with CT in four patients. These incorrect or indeterminate results were all related to the diagnosis of aortic invasion. No patient had a false-negative result. When indeterminate diagnoses were considered false-positive, sensitivity, specificity, and accuracy for resectability were 100%, 84%, and 87%, respectively, for MR and 100%, 80%, and 84%, respectively, for CT. We conclude that MR and CT have nearly the same accuracy in predicting resectability of tumors in patients with esophageal carcinoma.

Adenocarcinoma↗
PubMed1986

Effects of magnesium and sodium ions on the outer membrane permeability of cephalosporins in Escherichia coli.

Both Mg2+ and Na+ stimulated the outer membrane permeation of negatively charged cephalosporins in Escherichia coli without any significant alteration of the permeation of a zwitterionic cephalosporin. Such stimulation was not observed in an E. coli mutant lacking porins. The stimulation was caused by the direct interaction between the cations and the porin pores, which resulted in a decrease in cation selectivity of both the Omp F and Omp C porin pores.

Bacterial Outer Membrane Proteins↗
PubMed1985

Difference in pathway of Escherichia coli outer membrane permeation between penicillins and cephalosporins.

The differences in the outer membrane permeation between two major subgroups of beta-lactam antibiotics were studied. The permeation of cephalosporins was closely related to porin channels in the outer membrane. In contrast, the outer membrane permeation of penicillins did not decrease in porin-deficient mutants and, in Rd-type mutants, their permeability became proportional to the hydrophobicity of the molecules. The activation enthalpy of the penicillin permeation was significantly larger than that of cephalosporins. These observations indicate that penicillins can use the hydrophobic region for the major route of outer membrane passage whereas the cephalosporin permeation is restricted to the pathway via the porin pore.

Ampicillin↗
PubMedDate not supplied

Nonpalpable lymph nodes of the neck: assessment with US and US-guided fine-needle aspiration biopsy.

Ultrasound (US) and US-guided fine-needle aspiration biopsy (FNA) were performed in 91 nonpalpable neck nodes of 70 patients, 98% of which had known malignancy. Various sonographic findings were evaluated for predicting malignancy. The accuracy of US-guided FNA for detecting malignancy was 88%, with 96% sensitivity and 94% specificity. The ratio of minimal to maximal axial diameters of a node was most valid for predicting malignancy with US. A ratio of more than 0.55 yielded the highest accuracy (80%) (92% sensitivity, 63% specificity). Addition of any other factors to this criterion did not improve its accuracy. US and US-guided FNA are accurate for the assessment of nonpalpable neck nodes. Lymph nodes with a round configuration should be biopsied in patients with known malignancy.

Adolescent↗