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Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 577 records · Page 32Linked to original sources
PubMed1991

Participation of the parasympathetic nervous system in the development of activity-stress ulcers.

The present study investigates the effects of truncal vagotomy and drug treatment, comprising atropine methylbromide and chlorisondamine, on the development of activity-stress ulcers in rats. To induce gastric lesions, female rats were housed individually in activity-wheel cages and subjected to a food-restricted schedule of only 1 hr food availability per day. Bilateral truncal vagotomy significantly prevented gastric ulceration, while those rats with vagotomy showed more running activity than sham-operated rats. Daily treatment with either methylatropine (3 and 6 mg/kg, s.c.) or chlorisondamine (2 and 4 mg/kg, i.p.) also significantly decreased the severity of lesions without a significant reduction in running activity. This evidence suggests that the development of activity-stress ulcers is mainly due to the hyperactivity of the peripheral parasympathetic nervous system.

Animals↗
PubMed1991

Effects of long-term high-fiber diet on macrovascular changes and lipid and glucose levels in STZ-induced diabetic SD rats.

The effects of long-term high-fiber diet on lipid and glucose levels and the histological changes in the coronary arteries and thoracic aorta in STZ-induced diabetic SD rats were investigated. During the first 4 weeks of the study period, all diabetic rats were given regular chow plus water after which, all were grouped according to the following diet regimen: group II, no added cholesterol and glucomannan; group III, no added cholesterol but with glucomannan supplement, group IV, with added cholesterol but no glucomannan supplement; and group V, with both cholesterol and glucomannan supplements. 15% weight of glucomannan and 1.5% weight of cholesterol in regular rat chow were used as supplements when indicated. Non-diabetic rats which received only regular chow served as the control group (group I). In the 18th week all rats were sacrificed and weight gain, glucose, total cholesterol, HDL-cholesterol, triglyceride and lipid peroxidase concentrations were determined. Selected portions of the heart and thoracic aorta were histologically examined. Weight gain was higher in rats supplemented with glucomannan than in those without glucomannan supplements, but the difference is not significant. A lowering tendency in glucose levels was likewise observed. Furthermore, total cholesterol and HDL-cholesterol levels were lower and higher, respectively in diabetic rats receiving glucomannan. Although the triglyceride levels were similar in all rats, lipid peroxidase levels were significantly lower in rats with high-fiber diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Reconstruction of finger and elbow function after complete avulsion of the brachial plexus.

Simultaneous reconstruction of elbow and finger function with free muscle and nerve transfers after complete avulsion of the brachial plexus (nerve roots C5 to T1) and its long-term results are presented. The basic procedure combined free or vascular pedicle latissimus dorsi muscle transfer with reinnervation by the spinal accessory nerve to obtain elbow and finger flexion, intercostal nerve transfer of the radial nerve to activate elbow and wrist extensors, and suture of the supraclavicular nerve or intercostal sensory rami to the median nerve to restore hand sensibility. Six patients had some or all of these procedures. Postoperative follow-up ranged from 2 to 5 years. Elbow function was restored completely, and some finger flexion was achieved in all cases, although a dynamic splint was necessary to straighten the digits. Patients have continued to improve in grasp power and finger control. This procedure appears to be promising for the restoration of basic hand function in severely handicapped patients.

Accessory Nerve↗
PubMed1991

Determination of instantaneous and average blood flow rates from digital angiograms of vessel phantoms using distance-density curves.

We have developed a new method for quantitation of blood flow rates based on determination of the spatial shift of the distribution of contrast material in opacified vessels in digital angiograms that are acquired while the contrast material proceeds through the vessel. The distance that the contrast material travels during the time between image acquisitions is determined by comparison of density-vs.-distance curves, which represent the distribution of contrast material along the length of the vessel in the respective images. The flow rate between image acquisitions is calculated by multiplication of the distance traveled by the frame rate and the vessel cross-sectional area. Therefore, for high-frame-rate acquisitions, "instantaneous" flow rates can be determined. In these vessel-phantom studies, the root-mean-square (RMS) difference between instantaneous flow rates measured with our technique and those measured with an electromagnetic method was 2.9 ml/sec; the RMS difference for average flow rates was 0.8 ml/sec.

Absorptiometry, Photon↗
PubMed1991

Effect of heart-size parameters computed from digital chest radiographs on detection of cardiomegaly. Potential usefulness for computer-aided diagnosis.

Heart size is an important and useful diagnostic parameter in chest radiographs. However, there is a large variation in the subjective judgment of cardiac enlargement (cardiomegaly). To reduce this subjective element, the authors are developing an automated system for quantitative analysis of heart size in digital chest radiographs. Four hundred chest radiographs were reviewed initially by two radiologists and were classified into two groups: those with and those without cardiomegaly. Another radiologist reviewed 47 images which were not classified consistently in the initial review. The authors used these radiographs to construct a database for determination of cardiomegaly. Numerous parameters related to heart size were obtained in a semiautomated analysis of these radiographs, and the use of each parameter for detection of cardiomegaly was evaluated by means of receiver operating characteristic analysis. The authors also examined whether the accuracy would be improved when they applied multivariate analysis to a pair of parameters. From the analyses of the individual parameters, the automatically determined cardiothoracic ratio was found to be the single most effective measure for detecting cardiomegaly in chest radiographs. However, multivariate analysis provided results superior to those with an individual parameter.

Cardiomegaly↗
PubMed1991

Free vascularized thin corticoperiosteal graft.

This paper describes a new thin corticoperiosteal graft harvested from the medial condylar and supracondylar areas of the femur. It is based on the articular branch of the descending genicular artery and vein and consists of periosteum with a thin (0.5 to 1.0 mm) layer of outer cortical bone. By retaining the cortex, the cambium layer is preserved, and this is thought to have a better osteogenic capacity than vascularized periosteal grafts. This graft was used to treat six patients with fracture nonunion of the upper extremity in which conventional treatment had failed. Uneventful bony union was achieved in all patients within 10 weeks.

Adult↗
PubMed1991

Direct comparison of conventional and computed radiography with a dual-image recording technique.

To compare the image quality of computed radiographic (CR) with conventional screen-film images, the authors used a dual-image recording technique. Images were simultaneously acquired with a conventional screen-film combination and a storage-phosphor imaging plate loaded into a single cassette. Wiener spectra and modulation transfer function were compared for both image types. A preliminary observer performance test was conducted with chest images obtained with the dual-image recording technique on portable and fixed equipment. Analysis of physical parameters and observer test results suggests that the conventional screen-film system can provide slightly superior image quality, although the CR system has some advantage in bedside applications.

Confidence Intervals↗
PubMed1991

Data compression: effect on diagnostic accuracy in digital chest radiography.

High-resolution digital images make up very large data sets that are relatively slow to transmit and expensive to store. Data compression techniques are being developed to address this problem, but significant image deterioration can occur at high compression ratios. In this study, the authors evaluated a form of adaptive block cosine transform coding, a new compression technique that allows considerable compression of digital radiographs with minimal degradation of image quality. To determine the effect of data compression on diagnostic accuracy, observer tests were performed with 60 digitized chest radiographs (2,048 x 2,048 matrix, 1,024 shades of gray) containing subtle examples of pneumothorax, interstitial infiltrate, nodules, and bone lesions. Radiographs with no compression, with 25:1 compression, and with 50:1 compression ratios were presented in randomized order to 12 radiologists. The results suggest that, with this compression scheme, compression ratios as high as 25:1 may be acceptable for primary diagnosis in chest radiology.

Humans↗
PubMed1991

Lymphocyte subpopulations and function in childhood IgA nephropathy.

In order to examine T lymphocyte function in childhood IgA nephropathy, 13 patients and 10 age-matched control subjects were studied. T lymphocyte function was examined in terms of in vitro immunoglobulin synthesis by peripheral blood mononuclear cells (PBMC) and CD4-depleted (suppressor-rich) and CD8-depleted (helper-rich) PBMC in both unstimulated and pokeweed mitogen (PWM) and Staphylococcus aureus Cowan I (SAC) stimulated cultures. T lymphocyte subpopulations were examined by two-color immunofluorescence analysis using Fluorescein-Activated Cell Sorter (FACS). Children with IgA nephropathy showed (1) a significant increase in IgA synthesis by PBMC with or without mitogen stimulation, (2) a significant increase in IgG and IgA synthesis by CD4-depleted (suppressor-rich) PBMC, (3) a significant increase in IgG and IgA synthesis by CD8-depleted (helper-rich) PBMC, and (4) a significant decrease in suppressor-inducer T cells (Leu3a+Leu8+). These results suggest that a decrease in suppressor-inducer T cells, impaired suppressor T cell function and hyperactivity of helper T cell function are responsible for the increase in IgA production in children with IgA nephropathy.

Adolescent↗
PubMed1991

Systemic histopathology of rats with CCl4-induced hepatic cirrhosis.

Systemic histopathological examinations were carried out on rats with CCl4-induced hepatic cirrhosis. Moderate congestion in the spleen, prominent oedema in the focal acinar cell degeneration in the pancreas, marked haemorrhage and phagocytosis of haemosiderin by macrophages in the pancreaticoduodenal lymph node, appearance of monocytes bearing haemosiderin-like granules in the pulmonary arteries and cardiac right atrium, and focal segmental glomerulosclerosis were consistently observed in rats with hepatic cirrhosis. In addition, a marked increase in number of target cells and the appearance of a small number of monocytes bearing haemosiderin-like granules were also commonly found in the peripheral blood smears of these animals. These findings are considered to be important in the use of the CCl4-induced model of hepatic cirrhosis in the rat.

Animals↗
PubMed1991

Lesions in the central nervous system of DBA/2 mice infected with the D variant of encephalomyocarditis virus (EMC-D).

The central nervous system (CNS) of DBA/2 mice inoculated i.p. with the D variant of encephalomyocarditis virus (EMC-D) (10(3) PFU/head) was examined up to 28 days postinoculation (28 DPI). The virus titer of CNS reached a maximum level at 4 DPI, and infectious viruses became undetectable by 28 DPI. Histopathologically, degeneration of neurons with virus antigens was observed in St. pyramidale hippocampi, Nuc. amigdaloideus corticalis and St. granulosum cerebelli of the brain and in Cornu ventrale of the thoracic to lumbar spinal cord at 6 DPI. In addition, in the spinal cord, demyelination was found in Funiculus ventralis and Funiculus lateralis at 6 DPI and it progressed to form spongiosis at 10 DPI. In correspondence with these virological and histopathological findings, hind limb paralysis developed in some mice at 6 DPI, and its incidence increased markedly to about 60% at 10 DPI.

Animals↗
PubMed1991

Acute infection of encephalomyocarditis (EMC) virus in Syrian hamsters.

One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters.

Acute Disease↗
PubMed1991

Histochemical study on the bile duct system of normal Mongolian gerbils.

The bile duct system of normal Mongolian gerbils was examined histochemically. The luminal surface membrane and apical cytoplasm of the biliary and gallbladder epithelial cells were stained with periodic acid-Schiff (PAS), alcian blue, pH 2.5 (AB) and high iron diamine (HID)-AB, and many epithelial cells of the common bile duct and gallbladder had weakly PAS-positive granular material in their supranuclear cytoplasm. Lectin-histochemically, these cells had binding sites to Concanavalia ensiformis (ConA), Dolichos biflorus (DBA), Glycine max (SBA), Ulex europeas-I (UEA-I), and Triticum vulgaris (WGA). On the other hand, the periductal glandular epithelial cells were not stained by any histochemical stainings. In addition to these light microscopic findings, the electron microscopic findings based on the periodic acid-silver methenamine method and avidin-biotin colloidal gold method for DBA and WGA suggested that the biliary and gallbladder epithelial cells of Mongolian gerbils secreted mucin with terminal sialic and sulfonic acid residues and that the lectin binding activity of mucin secreted from these cells was similar to that of mucin secreted from the periductal glandular epithelial cells of mice and rats.

Animals↗
PubMed1991

Comparative studies of some functional and morphological parameters in the livers of germfree, conventional and ex-germfree mice.

Some parameters of hepatic function and morphology were studied to compare germfree (GF) and conventional (CV) BALB/c mice. The levels of lipid peroxide (LPO) and aniline-hydroxylase (AH) activity in the livers and the serum total cholesterol (TC), triglyceride (TG) and phospholipid (PL) were significantly lower in GF than in CV 8-week-old mice. There were no significant differences in the histology and lectin-histochemistry of the livers in the GF and CV mice. On the other hand, in ex-GF mice which were induced by housing 4-week-old GF mice together with age-matched CV mice, the levels of LPO and AH activity in the liver and the serum TC, TG and PL contents increased rapidly within the first week and then approached values almost identical to those in CV mice 4 weeks later (i.e. at 8 weeks of age). The histologic picture of the liver was similar among the GF, CV and ex-GF mice.

Aniline Hydroxylase↗
PubMed1991

A microfluorometric method for simultaneous measurement of changes in cytosolic free calcium concentration and pH in single cardiac myocytes.

We describe a new system to measure changes in cytosolic free Ca concentration ([Ca2+]i) and pH (pHi) simultaneously using the dyes fura-2 and BCECF, and a random access camera with computer-operated synchronously-changing excitation and emission filters. Fluorescence intensities for fura-2 and BCECF were recorded from rat cardiac myocytes and calibrated in vivo using multiple-point determinations. [Ca2+]i and pHi were 88.6 +/- 32.8 nM and 7.16 +/- 0.12, respectively.

Animals↗