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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 343 records · Page 19Linked to original sources
PubMed1988

Acidosis-induced glucose intolerance is not prevented by adrenergic blockade.

The determinants of the altered glucoregulation in acidosis were investigated in anesthetized dogs. Because CO2 rapidly equilibrates and its effects are mediated by pH changes, CO2 inhalation was examined. Plasma acid-base composition, glucose, insulin, glucagon, and blood flows were evaluated before and after an intravenous glucose load (1.2 +/- 0.1 g/kg body wt) in normal and acidotic dogs with flow probes and catheters chronically implanted in the portal circulation. A simultaneous infusion of phentolamine (5 micrograms.kg-1.min-1), propranolol (3.5 micrograms.kg-1.min-1), both, or none was used. All acidemic dogs had lower hepatic extraction of insulin and greater hyperglycemia after the glucose challenge; thus the adrenergic system is not critical for these responses. Because arterial insulin levels were either normal (propranolol) or increased (all others) in acidosis, insulin resistance was likely. Insulin infusion (2 and 4 mU.kg-1.min-1) with euglycemic clamp and [3-3H]glucose documented that acidemia decreases peripheral glucose utilization and the insulin suppression of hepatic glucose production. Acidemia also enhances plasma glucagon levels, yet this effect plays a limited role in the observed hyperglycemia.

Acid-Base Equilibrium↗
PubMed1988

Histamine release from human leukocytes by platelet-activating factor.

Platelet-activating factor (PAF) was found to induce histamine release from human basophils in mixed leukocytes in the presence of cytochalasin B. The reaction was rapid and dependent on temperature. The release was lower at a high concentration of PAF and was inhibited by EDTA, suggesting a noncytolytic mechanism. CV-3988, a PAF antagonist, inhibited the reaction dose-dependently. PAF acted as an IgE-independent stimulus, but PAF-induced histamine release from leukocytes of allergic asthmatics, who had elevated serum IgE levels, was significantly higher than that from leukocytes of controls. These results suggest that PAF-induced histamine release is useful for studying the role of PAF in the pathogenesis of allergic disorders including bronchial asthma.

Adult↗
PubMed1988

Coronary angiography of Kawasaki disease with the coronary vasodilator dipyridamole: assessment of distensibility of affected coronary arterial wall.

The authors evaluated the distensibility of the coronary arterial wall by pharmacoangiography with intravenous administration of dipyridamole in 38 patients with Kawasaki disease. In the acute stage of the illness, the coronary arteries were evaluated for aneurysms by two-dimensional echocardiography. After the acute stage of the illness, selective coronary cineangiographies were performed by Seldinger's method under general anesthesia before and after intravenous administration of 0.6 mg/kg of dipyridamole for four minutes. The calibers of aneurysms and normal appearing segments of coronary arteries, at most 7 segments in 1 patient, were measured before and after dipyridamole administration on the high-quality cineangioanalyzer and percentages of coronary arterial dilatation were calculated. In 14 cases without evidence of coronary arterial lesions, the distensibility was 10.2 +/- 4.7% (mean +/- SD). The distensibility of 32 aneurysms in 16 cases was 0.6 +/- 1.1% and was significantly decreased (p less than 0.001). In 24 cases with coronary arterial lesions, aneurysms, stenosis, or obstruction, the distensibility of normal appearing segments of coronary arteries was 4.5 +/- 4.9% and was significantly decreased (p less than 0.001). This method is useful in evaluating distensibility and appears to be effective in detecting pathologic changes of the coronary arterial wall, even if it appears normal in shape. The patient with previously diseased coronary arteries should be kept under careful longterm surveillance.

Acute Disease↗
PubMed1988

An analysis of in vitro T cell responsiveness in nontuberculous mycobacterial infection.

In vitro cell-mediated immunity was examined in patients infected with nontuberculous mycobacteria, Mycobacterium avium-intracellulare complex in Japan. Peripheral blood lymphocytes of patients, as compared with those of tuberculous patients or tuberculin-positive healthy donors, showed depressed in vitro blastogenic responses to purified protein derivative of tuberculin (PPD), not only to PPDs of Mycobacterium tuberculosis but also to PPD-B and PPD-Y of M intracellulare and M kansasii, respectively. Nonspecific lymphocyte blastogenic responses to concanavalin A, phytohemagglutinin and pokeweed mitogen were normal. Analysis of defective in vitro PPD-induced lymphocyte blastogenic responses in these patients revealed that PPD-induced interleukin 2 (IL-2) production was impaired whereas PPD-induced IL-2 responsiveness was normally developed after PPD stimulation. Therefore, addition of exogenous recombinant human IL 2 substantially recovered the in vitro depressed PPD-induced blastogenic responses in these patients with nontuberculous mycobacterial infection.

Cells, Cultured↗
PubMed1988

Plain chest radiograph with computed radiography: improved sensitivity for the detection of coronary artery calcification.

The ability of computed radiography (CR) with photostimulable phosphor to detect coronary artery calcification (CAC) was compared with conventional radiography with the film-screen method. Posteroanterior and lateral chest radiographs were reviewed that had been obtained with both methods in 77 patients with a variety of heart diseases. Cineangiography confirmed that 31 patients had CAC (left CAC in 31 patients, right CAC in 11) and that 46 patients had no CAC. For left CAC, the sensitivity of CR was 71%, significantly higher than that of conventional radiography (32%, p less than .01). For right CAC, the sensitivity of CR was only 27%, but that of conventional radiography was 0%. The specificities in detecting CAC were similar for both methods (CR, 96%; conventional method, 100%). Fine anatomic details of calcified foci were seen more clearly on CR. Chest imaging with the CR system is a promising method for detecting CAC.

Adolescent↗
PubMed1988

[Intramedullary invasion by a cervical cystic neurinoma--a case report].

This report examines a case involving a huge cystic cervical neurinoma existing extra- and intramedullary. The histogenesis of intramedullary neurinoma, pathohistogenesis of large intratumoral cyst are discussed. The role of Magnetic Resonance Imaging (MRI) in the diagnosis of spinal tumors is also discussed. A 23-year-old male was admitted to our ward or having tetraparesis. On admission, spastic tetraparesis and sensory disturbance below level C 2 were noticed. Electrophysiological examinations suggested a left-dominant intraspinal lesion. Conventional radiological examinations revealed widened cervical spinal canal, swelling of the spinal cord at level C 6-7, left extramedullary mass at level C 5, and a complete block at level C 4. MRI disclosed intramedullary tumor existing from the medulla oblongata to the lower cervical including macrocysts, and an extramedullary tumor on the left at level C 3-5. Surgical exploration was made and both of intra- and extramedullary tumors were confirmed to be neurinoma. The postoperative course was favourable. The patient was able to walk with aids, and was referred to the rehabilitation center 6 months after the operation. In histological investigations, the major components of the tumors were typically Antoni-A type neurinoma, and an abundant hemosiderin deposits. There were many hyalinized whorling portions around the cysts. Though spinal neurinoma is the most common spinal tumor, the intramedullary neurinoma is extremely rare. Only 31 cases have been reported as far as we could investigated. The histogenesis of this type of lesion is still unsettled.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Biochemical, histological, and biomechanical analyses of canine tendon.

To define the matrix composition and architecture of canine flexor tendon, and to correlate tissue structure with applied mechanical loading, five anatomical regions of flexor tendon were studied. Histologically, two prominent fibrocartilaginous areas were observed on concave aspects of the tendon. The location of the major fibrocartilaginous area at the metacarpophalangeal joint correlated well with the region predicted by biomechanical modeling to be under greatest compressive loads during standing and claw movement. Comparative biochemical analysis showed an elevated water content, a five-fold higher hexuronic acid content, and a larger hydroxylysine/hydroxyproline ratio in this region relative to that for more tendinous areas. The major glycosaminoglycan component of fibrocartilaginous areas was chondroitin sulfate, whereas in other areas dermatan sulfate and hyaluronic acid dominated. Cell density and DNA analyses indicated a slightly higher cellularity for fibrocartilaginous areas and the region of vinculum insertion. These data document the existence of discrete areas of specialization within the flexor tendon that appear to be an adaptation to nutritional and mechanical factors.

Animals↗
PubMed1987

Effect of postnatal age on the ultrastructure of six anatomical areas of canine flexor digitorum profundus tendon.

We report findings of a transmission electron microscopic study comparing the morphological appearance of cells and extracellular matrix of two fibrocartilaginous regions of canine flexor digitorum profundus (FDP) tendon with that for typical tendinous regions. In addition, we determined the size distribution of collagen fibrils in six anatomical areas of the tendon from animals of three different ages. Average collagen fibril diameters for each of the six anatomical sites of 11-week-old FDP tendon were consistently different from that for older tissue. As growth proceeds, fibrils in tendinous regions almost double in size and take on a broad bimodal distribution. Collagen diameters in fibrocartilaginous areas do not increase, but rather decrease in size with age. Finally, the cells and associated pericellular matrix of fibrocartilaginous areas of adolescent and mature FDP tendon are ultrastructurally distinct from those of typical tendinous regions. On the contrary, the cellular morphology of 11-week-old tendon was invariant regardless of the anatomical region examined. In summary, fibrocartilage of canine FDP tendon, although not evident at 11 weeks of age, is well established by 6-12 months after birth and is the result of cellular and extracellular matrix specialization.

Aging↗
PubMed1987

Nasal dermal sinus and dermoid cyst with intrafalcial extension. Case report and review of literature.

Congenital nasal dermal sinus is an unusual lesion which comprises about 11%-12% of all cranial dermal sinuses. The sinus tract seldom extends intracranially and an associated intrafalcial inclusion cyst is extremely rare. The authors report a case of nasal dermal sinus and dermoid cyst with intrafalcial extension in a boy aged 1 year 4 month. Previous reports of this rare lesion are reviewed and the possible pathogenesis discussed.

Dermoid Cyst↗
PubMed1987

Recombinant human interleukin-2 reverses in vitro-deficient cell-mediated immune responses to tuberculin purified protein derivative by lymphocytes of tuberculous patients.

In vitro lymphocyte proliferative response to purified protein derivative of tuberculin (PPD) was investigated in patients with tuberculosis. Peripheral blood lymphocytes (PBL) from patients with advanced, refractory tuberculosis showed a significantly depressed response compared with the response of PBL from patients with newly diagnosed tuberculosis (P less than 0.01). A further characterization of this low responsiveness to PPD revealed that PBL from these advanced tuberculous patients failed to generate interleukin-2 (IL-2) in response to PPD stimulation. IL-2 receptor (Tac antigen) expression on the surface of T cells after PPD stimulation was also impaired, although to a lesser extent, in the patients with advanced, refractory tuberculosis. We attempted to overcome the depressed in vitro response observed in PBL from patients with advanced, refractory tuberculosis and found that the addition of exogenous, recombinant IL-2 returned the depressed PPD-induced PBL proliferation in these patients to the level of response observed in PBL from patients with newly diagnosed tuberculosis. The addition of recombinant IL-2 also had a restorative effect (up regulation) in vitro on the partly impaired PPD-induced IL-2 receptor expression by PBL from the patients with advanced, refractory tuberculosis. Our results suggest that recombinant IL-2 may offer a novel approach to the therapy of advanced, drug-resistant tuberculosis.

Humans↗
PubMed1987

Age-related change in ketone body metabolism: diminished glucagon effect on ketogenesis in adult rats.

The age-related changes in plasma ketone body levels and related substances such as carnitine and FFA of normal and streptozotocin diabetic rats, as well as its effects on glucagon-induced ketogenesis in isolated perfused rat livers, were examined in this study. The degree of increase of acetoacetate (AcAc) in adult rats (50-week-old) after a 36-h fasting period in both normal and diabetic rats was significantly smaller than that of young rats (8-week-old). Plasma total carnitine tended to decrease with aging. On the other hand, the plasma levels of FFA and glucagon in fasted adult rats were significantly higher than those in young rats. In parallel with the in vivo observation, the basal output of AcAc, but not 3-hydroxybutyrate, from adult rat livers was significantly smaller than that of the young normal and diabetic rats. The level of glucagon-stimulated AcAc output from the young rat liver was significantly higher than that from the adult rat liver in both the normal and diabetic rats. This study demonstrates that the hepatic unresponsiveness to glucagon in terms of its ketone body production by aging may be one of the major causes of hyperosmolar nonketotic coma in elderly people.

3-Hydroxybutyric Acid↗
PubMed1987

Postprandial changes in plasma ketone body and carnitine levels in normal and non-insulin-dependent diabetic subjects.

We have examined changes in plasma ketone bodies and their related metabolites after the ingestion of a mixed meal in normal and NIDDM (non-insulin-dependent diabetes mellitus) using a highly sensitive colorimetric method. In normal subjects, fasting plasma acetoacetic acid (AcAc) and 3-beta-hydroxybutyric acid (3-OHB) concentrations were 40.2 +/- 2.9 and 21.3 +/- 4.0 microM, respectively. The total carnitine level in fasting plasma was 48.2 +/- 3.2 microM and acyl/free was 0.34 +/- 0.12. These values did not change significantly after the meal. In diabetic subjects, fasting AcAc and 3-OHB levels were 57.9 +/- 3.5 and 97.9 +/- 14.7 microM, respectively and these values especially 3-OHB, decreased almost to the normal level by 4 h after the meal. The total carnitine level in the fasting plasma of diabetics was 48.7 +/- 2.8 microM and acyl/free was 0.58 +/- 0.09. Such characteristics were observed when their plasma glucose had been completely normal for more than 10 days. In patients treated with sulfonylurea, the fasting ketone body level, especially 3-OHB, was significantly lower than that of diabetics treated with insulin or diet alone, whereas the fasting plasma glucose level and its postprandial increase were higher than those of the others. These results demonstrate that measurement of the plasma ketone body (especially 3-OHB) level is a sensitive tool for monitoring the metabolic status of NIDDM.

Adult↗
PubMed1987

Postprandial glucose, insulin and glucagon responses to meals with different nutrient compositions in non-insulin-dependent diabetes mellitus.

Postprandial glycaemic and hormone responses to meals with different nutrient compositions and their heterogeneity were evaluated in 16 non-insulin-dependent diabetic patients and 5 healthy volunteers. Five kinds of nutrient stimulation--75 g glucose, a Japanese mixed meal (400 kcal, carbohydrate 60%, protein 14%, fat 26%), a high protein meal (300 kcal, C 26%, P 64%, F 10%), a high fat meal (300 kcal, C 23%, P 5%, F 72%) and 20 g iv glucose--was given to each subject. On the average, in both normal and diabetic subjects, the increases in plasma glucose (PG) and insulin (IRI) were the largest with the oral glucose load and the smallest with the high protein meal. The ratio of increase in IRI and PG (sigma delta IRI/sigma delta PG) was the highest with the high protein meal and the lowest with the oral glucose load. sigma delta IRI with the high protein meal and the high fat meal were the same in normal and diabetic subjects. However, each of the 16 NIDDM patients and 5 normal volunteers exhibited a different pattern of response to the nutrient stimuli and no definite subgroup could be classified. There was no correlation between metabolic responses and family history of diabetes mellitus, duration of diabetes, body mass index and fasting plasma glucose. The present results suggest the nearly intact capacity of insulin secretion in NIDDM in response to a high protein or high fat meal and the difficulty of subclassification in NIDDM according to the glycaemic and hormone responses to the different nutrient stimuli.

Adult↗
PubMed1987

Hormone release from pancreatic islets perfused from venous side.

Directional blood flow in pancreatic islets may be important for regulation of islet hormone release. We therefore perfused an isolated canine pancreas via the celiac artery (arterial perfusion) and then via the portal vein (venous perfusion) in the same pancreas. Basal insulin and glucagon levels and their rate of release in response to 10 mM arginine, 11 mM glucose, 500 pg/ml somatostatin, or 500 pg/ml glucagon were similar under both conditions. However, the inhibition of glucagon release due to somatostatin and its recovery after the cessation of somatostatin infusion was poor in the case of venous perfusion. The basal somatostatin level and its release in response to 10 mM arginine, 11 mM glucose, and 500 pg/ml glucagon during venous perfusion was significantly higher than that during arterial perfusion. From these results, it is speculated that the directional blood flow in pancreatic islets may not be essential for regulation of hormone release from the canine pancreas or that such directionality does not exist in canine pancreatic islets, and that a considerable portion of released somatostatin may be taken up by the pancreas located downstream--probably in the exocrine pancreas.

Animals↗