PubMed Health⌕ Search

Biomedical subjects

N Matsunaga

Publications and source records attributed to N Matsunaga.

At least 19 recordsLinked to original sources
PubMed1997

Thin-section oblique CT with 25 degrees cranially tilted images. Evaluation of pulmonary tumors adjacent to the interlobar fissures.

PURPOSE: Thin-section oblique CT with cranially tilted axial scans can provide better visualization of the interlobar fissures than thin-section CT with conventional axial scans. The purpose of this study was to evaluate the usefulness of oblique CT scans for pulmonary tumors adjacent to the interlobar fissures. MATERIAL AND METHODS: Cranially tilted and conventional axial images were obtained by thin-section CT in 10 patients with solitary pulmonary tumors adjacent to the interlobar fissures. Conventional CT with a 2-mm collimation and thin-section oblique CT with a 25 degrees cranial tilt were obtained. RESULTS: The images obtained by thin-section oblique scanning visualized the relationship between the pulmonary tumor and the interlobar fissures in all 10 patients, whereas in 6 patients the thin-section conventional images did not. The pulmonary tumors in these 6 patients included all 5 that were adjacent to the minor fissures. CONCLUSION: Thin-section oblique CT may be more useful than thin-section conventional CT in evaluating the relationship between pulmonary tumors and the minor fissures.

Adenocarcinoma↗
PubMed1997

SPECT with In-111 autologous platelets to detect residual splenic tissue in two patients with relapsed thrombocytopenia.

In two patients with relapsed thrombocytopenia, the authors used SPECT with In-111 labeled autologous platelets to identify residual splenic tissue after splenectomy. One case involved a previously splenectomized patient with idiopathic portal hypertension, while the other had relapsed chronic idiopathic thrombocytopenic purpura (ITP). In both patients, SPECT showed a higher In-111 uptake in the splenic tissues compared with planar images. In the patient with ITP, a small accessory spleen had been overlooked on abdominal CT because of post-operative changes, but it was identified by superimposition of SPECT/CT images. These cases indicate that In-111 platelet SPECT is useful in detecting and localizing residual accessory splenic tissue associated with relapsed thrombocytopenia.

Adult↗
PubMed1997

Radionuclide angiography and ventilation/perfusion studies in two patients with systemic arterial supply to the basal segment of the left lung.

The findings of radionuclide studies in two adult men with systemic arterial supply to the basal segment of the left lung without sequestration are reported. Radionuclide angiography with Tc-99m human serum albumin-diethylenetriamine showed that the lung was perfused by the systemic circulation rather than by the pulmonary artery. Ventilation and perfusion scans with Xe-133 and Tc-99m MAA showed a V/Q mismatch in this area, suggesting the presence of normal bronchial communication without a pulmonary arterial supply. These results also suggest the presence of a left-to-left shunt in the well-ventilated lung in this area. MRI and conventional angiography showed an aberrant artery arising from the descending thoracic aorta, supplying the basal segment of the left lung without a pulmonary artery. In both patients, left lower lobectomy showed normal alveobronchial structures without sequestration. Radionuclide angiography and ventilation/perfusion imaging appear to be reliable noninvasive methods for diagnosing this rare anomaly with a left-to-left shunt.

Adult↗
PubMed1997

Radionuclide imaging in emphysema after lung volume reduction surgery.

Three dimensional (3D) surface displays of dynamic Xe-133 and Tc-99m MAA SPECT were performed to evaluate regional lung function in two patients with pulmonary emphysema before and after thoracoscopic lung volume reduction surgery. The 3D displays were reconstructed using a color-illuminated, surface-rendering technique. For the Xe-133 studies, a fusion display of 3D equilibrium (EQ) and 3-minute washout (WO) images was used to show the distribution of Xe-133 retention, which were transparently seen within the entire lung contours delineated by the EQ image. In both patients, these 3D displays allowed an overview of the localized poorly functioning lungs with Xe-133 retention or reduced perfusion with geometric realism. The location and extent were more easily comprehended on the displays compared to the slice-by-slice presentations of tomograms. Postoperatively, the displays efficiently revealed restored function in the remaining lungs. The 3D surface displays of the two SPECT procedures providing topographic information of regional lung function appears to contribute to the treatment strategy of this surgery.

Aged↗
PubMed1997

Characterization of hepatic adenoma with atypical appearance on CT and MRI by radionuclide imaging.

The appearance of hepatic adenomas on CT and MRI are highly variable because of their varied histopathology, and images of adenomas are at times indistinguishable from those of other hepatic tumors. The authors present two patients with hepatic adenomas with extremely atypical CT and MRI manifestations demonstrating a "nodule-in-nodule" appearance. Radionuclide imaging in both patients showed decreased Ga-67 uptake in the adenomas compared to normal liver, negative colloid (Tc-99m phytate) uptake in the adenomas, and early uptake and subsequent retention of Tc-99m PMT. This correctly characterized the unique histopathologic features of the resected tumors. Radionuclide imaging using a combination of radiotracers may play an important role in aiding the diagnosis of this rare benign tumor, despite variable CT and MRI appearances.

Adenoma, Liver Cell↗
PubMed1997

Three-dimensional surface displays of perfusion SPET in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery.

A modified, three-dimensional display was applied to 99Tcm-macroaggregated albumin (99Tcm-MAA) SPET to help assess the effect of thoracoscopic lung volume reduction surgery (LVRS) on regional lung perfusion. Surface-rendered three-dimensional images for 99Tcm-MAA and xenon-133 (133Xe) equilibrium (EQ) SPET were obtained in 11 patients with pulmonary emphysema before and after LVRS. A single three-dimensional fusion display of both images was then reconstructed, and the perfused lungs were transparently visible through the lung contours delineated by the three-dimensional 133Xe EQ image. The extent of preserved perfusion in the lung (the perfusion index) was estimated using the ratio (%) of the total pixel numbers of the segmented perfusion data to those of the 133Xe lung volume data. The three-dimensional fusion display provided an overview of the distribution of hypoperfusion in the lungs with geometric realism and enhanced the perception of anatomic size and configuration compared with multiple tomograms and three-dimensional perfusion images without superimposition of three-dimensional 133Xe image. Post-operatively, it displayed restored perfusion in the remaining lungs, and changes in the perfusion index correlated with %FEV1 (r = 0.731, P = 0.0001) more closely than the perfusion data alone (r = 0.593, P < 0.01). This method is useful for directing LVRS and assessing its effectiveness, as it provides precise tomographic information on regional perfusion.

Aged↗
PubMed1997

Visualization of frontal postural hypoperfusion in patients with Takayasu arteritis with upright 99Tcm-HMPAO brain SPET.

Takayasu arteritis is a chronic inflammatory angiopathy involving the cerebral arteries. We performed upright and supine 99Tcm-HMPAO brain single photon emission tomography (SPET) to investigate the cerebral perfusion pattern in eight patients with Takayasu arteritis, and we compared the results with those acquired using 123I-IMP and acetazolamide in six patients. SPET images were evaluated visually and semi-quantitatively. Hypoperfusion was visually detected in all eight patients during the provocative upright test with 99Tcm-HMPAO, and in three of six tested using acetazolamide and 123I-IMP. Semiquantitative analysis revealed that the mean cortical-to-cerebellar ratio in the upright position was significantly changed compared to that in the supine position in the right frontal area (from 0.86 +/- 0.07 to 0.91 +/- 0.09; P < 0.05). Change was also seen in the left frontal area (from 0.85 +/- 0.08 to 0.91 +/- 0.08; P < 0.05). No significant change was seen in other cortical areas with the upright test or in any areas with the acetazolamide test. We postulate that reduced arterial compliance may cause frontal postural hypoperfusion in patients with Takayasu arteritis due to poor functioning of autoregulation and arterial stenosis or occlusion. We conclude that the provocative upright test with 99Tcm-HMPAO brain SPET can detect abnormal patterns of cerebral perfusion in patients with Takayasu arteritis that might be missed by brain SPET using 123I-IMP and acetazolamide.

Acetazolamide↗
PubMed1997

Ventilation abnormalities in obstructive airways disorder: detection with pulmonary dynamic densitometry by means of spiral CT versus dynamic Xe-133 SPECT.

PURPOSE: To evaluate pulmonary dynamic densitometry (PDD) by means of spiral computed tomography (CT) for detection of ventilation abnormalities in obstructive airways disorders compared with dynamic xenon-133 single photon emission CT. MATERIALS AND METHODS: Eight-second spiral CT was performed during two to three respiratory cycles in six healthy volunteers, 19 patients with airways disorder, and six patients with restrictive lung disease. The data sets were reconstructed as 36 1-second temporally overlapping images at 0.2-second intervals, and regional PDD curves were displayed. Regional ventilation was assessed by means of Xe-133 clearance time. RESULTS: Normal lungs showed smooth, sinusoidal PDD curves with maximal amplitude in lung attenuation change (MALAC) of 54.9 HU +/- 24.5, whereas lungs with obstructive airways disorders with prolonged Xe-133 clearance showed significantly diminished MALAC (31.6 HU +/- 20.1, P < .0001), accompanied by irregularity, asynchronous phase, and deterioration of normal ventral-to-dorsal gradients in MALAC and lung attenuation. Lungs with restrictive diseases without prolonged Xe-133 clearance did not show statistically significant reduction in MALAC. In a total of 251 lung regions, regional MALAC correlated inversely with Xe-133 clearance time (r = -.842). CONCLUSION: PDD by means of spiral CT is acceptable for the detection of ventilation abnormalities in obstructive airways disorder.

Adult↗
PubMed1997

Gallbladder disease: appearance of associated transient increased attenuation in the liver at biphasic, contrast-enhanced dynamic CT.

PURPOSE: To evaluate the frequency, location, and appearance of transient increased attenuation in the liver during arterial-phase helical or incremental computed tomography (CT) in patients with gallbladder disease without hepatic extension. MATERIALS AND METHODS: Findings in dynamic CT examinations in 31 patients with surgically proved gallbladder disease not extending into the liver and in 31 control patients without gallbladder disease were retrospectively reviewed and correlated with findings in other imaging examinations. RESULTS: Areas of transient increased hepatic attenuation (n = 27) were identified in 22 of 31 patients with gallbladder disease and in only one of 31 control patients. The difference in these findings was statistically significant (P < .001). In the 27 areas of transient increased hepatic attenuation, these findings were categorized as curvilinear or nodular attenuation adjacent to the gallbladder fossa in 13 (48%), segmental or subsegmental attenuation in segment IV and/or V in seven (26%), lobar attenuation in the left lobe (segments II-IV) in four (15%), and nodular attenuation seen as an early enhancing "pseudolesion" in segment IV in three (11%). Hepatic angiography performed in 10 of the 22 patients showed early depiction of the dilated cystic vein (n = 8) and direct communication with the portal branches (n = 2). CONCLUSION: Transient increased attenuation in the liver had a variable appearance at dynamic arterial-phase CT in most patients with gallbladder disease. This attenuation was most likely due to increased blood flow from the hepatobiliary system.

Adult↗
PubMed1997

Abdominal aortic aneurysm: rupture associated with the high-attenuating crescent sign.

PURPOSE: To determine the histopathologic features of the ruptured abdominal aortic aneurysm associated with the high-attenuating crescent sign on computed tomographic (CT) scans and to suggest a possible mechanism for the rupture. MATERIALS AND METHODS: Histopathologic examination was performed with specimens from six patients with a ruptured aneurysm associated with the high-attenuating crescent sign and from eight patients with a nonruptured aneurysm and in whom the high-attenuating crescent sign was not present. RESULTS: Acute hemorrhage in the mural thrombus or aneurysmal wall coincident with the high-attenuating crescent sign was present in all six patients with a ruptured aneurysm. Clefts with seeping blood in the mural thrombus were seen in four patients with a ruptured aneurysm; intact specimens of the mural thrombus were not obtained in two patients because the hemorrhagic thrombus was fragile. Clefts with seeping blood were scattered from the inner to the outer layers of the mural thrombus. In the eight patients with uncomplicated aneurysm, no hemorrhage in the mural thrombus or aneurysmal wall was noted, and no clefts were seen. CONCLUSION: The cause of high-attenuating crescents in a ruptured aneurysm may be attributed to hemorrhage in the mural thrombus or in the aneurysmal wall.

Adult↗
PubMed1997

Inhibition of GH releasing factor (GRF)-induced GH secretion by intraruminal infusion of volatile fatty acids (VFA) in sheep.

A VFA mixture solution containing acetate, propionate and butyrate (the molar ratio of acetate, propionate and n-butyrate = 61.7:24.3:14.0) was infused into the rumen at various rates (53.5, 107 and 214 mumol kg-1 min-1) over 6 h to examine the effects on basal and growth hormone-releasing factor (GRF, 0.25 micrograms kg-1)-induced increase in secretion of GH, insulin, glucagon and somatostatin (SRIF) in five castrated male sheep. Intraruminal infusion of the VFA mixture into the 18-h-fasted animals at the rates of 53.5, 107 and 214 mumol kg-1 min-1 finally raised the total intraruminal VFA concentration from 91.4 to 100.2 (P > 0.05), 175.9 (P < 0.05) and 234.5 (P < 0.05) mmol l-1, respectively. A preliminary experiment showed that an infusion rate of 107 mumol kg-1 min-1 mimics the postprandial increase in ruminal VFA. The basal plasma GH concentrations (2 to 4 h after the start of VFA infusion) and the area under the profiles for GH release in response to the intravenous GRF injection, which was done 4 h after the start of VFA infusion, were significantly decreased by the VFA infusion rates of 107 and 214 mumol kg-1 min-1. Furthermore, the VFA infusion noticeably increased basal plasma concentrations of insulin, but it scarcely changed the basal levels of glucagon, SRIF and glucose. From these results we conclude that an increase in the ruminal VFA concentration, even within the physiological range, would suppress GH secretion from the ovine anterior pituitary, and that the postprandial rise in the ruminal VFA concentration may be one of the factors normally suppressing GH secretion in sheep.

Animals↗
PubMed1997

Competitive enzyme immunoassay for bovine growth hormone.

We developed an enzyme immunoassay (EIA) for bovine GH (bGH) which is based on indirect competitive immunoassay in culture medium from a bovine pituitary cell culture. 40 microliters cell culture samples (or bGH standard) and bGH antibody (rabbit anti-bGH) were added to the 96 well microplate coated with secondary antibody (Goat anti-rabbit IgG), and incubated for 24 h at 37 degrees C. Biotin-label bGH was added and incubated further for 24 h at 37 degrees C, and biotinylated bGH was linked with streptoavidin-peroxidase. Substrates for peroxidase were added to the plate and incubated for 1 h at 4 degrees C. The enzyme reaction was stopped with 4N H2SO4, and the absorbency at 450 nm was measured with an ELISA Reader. The coefficients of intra-assay and inter-assay variations were 4.13 approximately 7.59% and 3.71 approximately 8.27%, respectively. The regression equation and correlation coefficients with the radioimmunoassay (RIA) were y(RIA) = 1.9986 x (EIA) - 1.3921 and 0.9701 (n = 27), respectively. Collectively, the present assay provides a reliable alternative to RIA and offers the major advantage of eliminating radioactive reagents and counting equipment.

Animals↗
PubMed1997

Mechanisms of action of growth hormone-releasing peptide-2 in bovine pituitary cells.

We conducted this study to investigate the mechanisms of action of growth hormone-releasing peptide-2 (D-Ala-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2; GHRP-2) in bovine anterior pituitary primary cell culture. Doses of GHRP-2 from 10(-13) to 10(-7) M) increased (P < .05) GH secretion. The GHRP-2 (10(-7) M) and GH-releasing factor (GRF; 10(-7) M) administered together had an additive effect on the release of GH (P < .05). Somatostatin (1 microM) decreased GH secretion in response to GHRP-2 and(or) GRF (P < .05). Secretion of GH in response to GHRP-2 was blocked (P < .01) by a GRF receptor antagonist (.1 microM). Nifedipine (10 microM), a voltage-dependent Ca2+ channel blocker, inhibited (P < .01) GHRP-2-stimulated GH release. The GH release in response to GHRP-2 and 4 beta-phorbol-12-myristate-13-acetate (10(-7) M), a protein kinase C activator, was additive (P < .01). Forskolin (30 microM), a cAMP elevating agent, further stimulated (P < .01) the GH release in response to GHRP-2. Bovine GH concentrations in culture media were assayed by indirect competitive enzyme immunoassay. These results showed that GHRP-2 1) stimulates GH secretion from bovine pituitary cells, 2) may partially act via GRF receptor, 3) has GH secretion activity caused by Ca2+ influx via Ca2+ channels, and 4) may increase GH secretion via protein kinase C and cAMP pathways.

Animals↗
PubMed1997

No desensitization of the growth hormone (GH) response between GH-releasing peptide-2 and GH-releasing factor in calves.

We investigated the desensitization caused by growth hormone (GH)-releasing peptide-2 (D-Ala-D-beta Nal-Ala-Trp-D-Phe-Lys-NH2; GHRP-2) in vivo using calves. The GHRP-2 (12.5 micrograms.kgBW-1.h-1) or GH-releasing factor (GRF; .125 microgram.kgBW-1.h-1) were infused for 180 min into four calves, each followed by either GHRP-2 (12.5 micrograms/kg BW) or GRF (.125 microgram/kg BW) injection after 60 min. All treatments were given to all of the calves. The continuous infusion of GHRP-2 did not attenuate the GH secretion caused by a GRF bolus, and vice versa. Continuous exposure to GHRP-2 attenuated the GH secretion caused by a GHRP-2 bolus. In an additional experiment, two repetitive injections of GHRP-2 (12.5 micrograms/kg BW) at 1-, 2-, 3-, or 4-h intervals were administered. Attenuation of the GH response caused by GHRP-2 was maintained until 4 h. These results suggest that GHRP-2 is not cross-desensitized with GRF and that the mechanisms by which they cause GH release may be different in calves.

Animals↗
PubMed1997

[Usefulness of 3-D dynamic pulmonary xenon-133 SPECT for thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema].

Six patients with pulmonary emphysema scheduled to undergo thoracoscopic lung volume reduction surgery (TLVRS) were evaluated by three-dimensional (3-D) dynamic pulmonary xenon-133 SPECT. Serial 30-second dynamic SPECT data for equilibrium and washout (for 5 min) were acquired using a continuous repetitive rotating acquisition mode with a triple-detector SPECT system. SPECT data were reconstructed to 3-D images with a color, surface-rendering technique, and a 3-D fusion image of the 3-min washout image over the equilibrium image was obtained. Regional ventilation was visually assessed on the fusion 3-D images and quantified by xenon-133 half-washout time (T1/2) and mean transit time (MTT). The 3-D fusion image localized and lateralized the worst diseased sites with xenon-133 retention. Xenon-133 retention, T1/2 and MTT were reduced on these images in five patients with improved pulmonary function tests following TLVRS. However, xenon-133 retention was greater in one with asynchronous diaphragm movement after TLVRS. This modality will assist TLVRS in determining the lung resection target and in evaluating the treatment effect.

Endoscopy↗