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Biomedical subjects

A Yoshida

Publications and source records attributed to A Yoshida.

At least 649 records · Page 36Linked to original sources
PubMed1992

Retinal blood flow alterations associated with scleral buckling and encircling procedures.

The bidirectional laser Doppler technique and monochromatic photography were used to measure the absolute blood flow rate in the major temporal retinal arteries in seven patients following unilateral scleral buckling and encircling procedures, and in two patients before and after removal of scleral buckling elements. In the seven patients who had undergone uncomplicated scleral buckling procedures the arterial flow rates were on average 50% lower (p = 0.01) in the surgically treated eyes than in the contralateral eyes. Removal of scleral buckling elements in two patients produced increases of 73% and 44% in arterial blood flow rates.

Adult↗
PubMed1992

Ocular circulatory changes following scleral buckling procedures.

The effect of segmental scleral buckling (SB) on ocular circulation was evaluated by measurements of the ocular pulse amplitude (PA) and the ophthalmic artery pressure (OAP). In this study the OAP was defined as the intraocular pressure (IOP) at which the PA disappeared during increasing IOP. Twenty four patients with unilateral rhegmatogenous retinal detachment who underwent SB of varying extent were studied; the unoperated fellow eyes served as controls. Both the OAP and the ophthalmic perfusion pressures (OAP minus IOP) decreased significantly (p < 0.01) as the area of SB treatment increased. Follow-up measurements showed that the OAP was relatively lower up to 3 months postoperatively than after 3 months, and then remained stable. Our results indicated that SB affects the ocular pulse measurements and may decrease ocular blood flow because of decreased ophthalmic perfusion pressure, probably due to increased choroidal vascular resistance, and that the greater the extent of the SB treatment, the greater the possibility of decreased ocular blood flow.

Adult↗
PubMed1992

Gastrointestinal examinations with digital radiography.

Basic imaging properties and clinical usefulness of an upgraded digital radiography system were evaluated. The system, which has 1,024 x 1,024 and 2,048 x 2,048 matrices, was upgraded with smaller focal spots (0.3 and 0.8 mm) and reduced thickness of the photoconductive layer of the video camera. Screen-film and digital images (with and without postprocessing) of the upper and lower gastrointestinal (GI) tract were used in the clinical evaluation. Overall modulation transfer functions of the upgraded digital system were comparable to those of the screen-film system, especially at the lower spatial frequency. Threshold contrasts of the two systems were similar despite a 50% reduction in incident exposure for the digital system. For the upper GI tract, digital images processed with unsharp masking techniques were comparable in quality to screen-film images before and after upgrade of the system. For the lower GI tract, screen-film images were better than digital images, except for those produced with a 2,048 x 2,048 matrix with unsharp masking. Further evaluation of the system for examination of other parts of the body seems warranted.

Digestive System↗
PubMed1992

Detection of thyroid-stimulating antibody in patients with inflammatory thyrotoxicosis.

The detection of thyrotropin-binding inhibitory immunoglobulins (TBII) and/or thyroid-stimulating antibody (TSAb) has been reported in some patients with painless thyroiditis (PT) or subacute thyroiditis (SAT). However, its mechanism is unknown. TBII and TSAb measured using cultured FRTL-5 thyroid cells were evaluated in 18 patients with PT, 11 patients with SAT and a patient with SAT-like symptoms. In PT, we detected both TBII and TSAb activities in only 1 patient. This case had first come to our attention with subclinical hypothyroidism and had already had weakly positive TSAb activity (205.9%) 1 year before the present onset of PT. This patient had a transient thyrotoxicosis with a low uptake (24 h) of 123I (4.3%) and 821.0% TSAb activity, and subsequently developed a transient subclinical hypothyroidism. Even after 2 years, she still had positive TSAb activity (382.3%). In SAT, TBII and TSAb activities were not detected during the courses of any patients. A patient with transient thyrotoxicosis, who had a high uptake (30 min) of 99mTc (5.6%) and SAT-like symptoms (painful tenderness on right thyroid lobe and markedly accelerated erythrocyte sedimentation rate), showed positive activities of TBII (34.9%) and TSAb activity (1,366.9%). Histological findings by thyroid needle biopsy performed in the thyrotoxic phase showed coexistence of granulomatous inflammatory changes and hyperplasia with papillary folds of some residual follicular cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Two cases of persistent hypouricemia associated with diabetes mellitus.

Two patients with diabetes mellitus had persistent hypouricemia due to increased urate clearance; the degree of the apparent renal hypouricemia with uricosuria was quite mild. At the onset of diabetes, their serum urate levels were normal. Even after good diabetes control in both cases, hypouricemia continued. Based on the pharmacological evaluation in both patients, pyrazinamide administration could partially decrease urate clearance, however, suppression by pyrazinamide was less than in normal subjects, and probenecid increased urate clearance. These results suggest that the present cases had a renal abnormality affecting tubular presecretory reabsorption of urate, which might be due to diabetes mellitus.

Aged↗
PubMed1992

Retinal oxidation activity and biological role of human cytosolic aldehyde dehydrogenase.

The major cytosolic aldehyde dehydrogenase isozyme (ALDH1) exhibits strong activity for oxidation of retinal to retinoic acid, while the major mitochondrial ALDH2 and the stomach cytosolic ALDH3 have no such activity. The Km of ALDH1 for retinal is about 0.06 mumol/l at pH 7.5, and the catalytic efficiency (Vmax/Km) for retinal is about 600 times higher than that for acetaldehyde. Thus, ALDH1 can efficiently produce retinoic acid from retinal in tissues with low retinal concentrations (< 0.01 mumol/l). The gene for ALDH1 has hormone response elements. These findings suggest that the major physiological substrate of human ALDH1 is retinal, and that its primary biological role is generation of retinoic acid resulting in modulation of cell differentiation including hormone-mediated development.

Aldehyde Dehydrogenase↗
PubMed1992

Single-dose kinetics of primidone in human subjects: effect of phenytoin on formation and elimination of active metabolites of primidone, phenobarbital and phenylethylmalonamide.

Effect of repetitive administration of phenytoin (PHT) on the single-dose pharmacokinetics of primidone (PRM) was investigated in 3 healthy male subjects. The peak concentration of unchanged PRM was achieved at 12 and 8 h after the administration of PRM in the absence and the presence of PHT, respectively. The elimination half-life of PRM was decreased from 19.4 +/- 2.2 (mean +/- S.E.) to 10.2 +/- 5.1 h (p < 0.05) and the total body clearance was increased from 24.6 +/- 3.1 to 45.1 +/- 5.1 ml/h/kg (p < 0.01) in the presence of PHT. No significant change was observed for the apparent volume of distribution between the two treatments. In the absence of PHT, the measurable amount (> or = 0.1 mumol/l) of phenobarbital (PB) and phenylethylmalonamide (PEMA) did not appear in the serum until 5.3 and 1.3 h after the PRM administration, and the peak concentrations of PB and PEMA were achieved at 52 and 36 h, but the concentrations of both metabolites were very low (PB 1.3 mumol/l; PEMA 1.7 mumol/l). In the presence of PHT, within 0.8 and 0.5 h after the administration of PRM, the derived PB and PEMA appeared in the serum. About a 6-fold increase in the peak concentrations of both the metabolites were observed (PB 8.2 mumol/l; PEMA 11.0 mumol/l). No significant changes were observed for the elimination half-lives of both PB and PEMA in the absence and presence of PHT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Molecular cloning and sequencing of the extracellular pectate lyase II gene from Erwinia carotovora Er.

Erwinia carotovora Er produces three extra-cellular pectate lyases (PL I, II, and III). The gene for pectate lyase II (pelII) of E. carotovora Er was cloned and expressed both in Escherichia coli and E. carotovora Er. Localization experiments in E. coli showed that PL II was exclusively in the cytoplasmic space, while PL II was excreted into the culture medium. The complete nucleotides of the pelII gene were sequenced and found to include one open reading frame of 1122 bp coding for a protein of 374 amino acid residues. From comparison of the N-terminal amino acid sequence between the purified PL II and the deduced protein from the nucleotide sequence we reached the conclusion that the mature protein is composed of 352 amino acids with a calculated molecular weight of 38,169 and is preceded by a typical signal sequence of 22 amino acid residues. PL II had 90.1% and 82.9% homologies with PL I and PL III in amino acid sequence, respectively.

Amino Acid Sequence↗
PubMed1992

Recombinant human growth hormone stimulates B cell immunoglobulin synthesis and proliferation in serum-free medium.

In order to investigate the effects of growth hormone on human B cells, we studied immunoglobulin synthesis and [3H]-thymidine uptake by B cell lines, IM-9, GM-1056 and CBL, and purified tonsil B cells. Cells were cultured in a serum- and albumin-free medium, Cosmedium-001 to exclude interaction between a certain growth-promoting substance and any unknown substances that serum may contain. GH enhanced IgG synthesis and [3H]-thymidine uptake by IM-9 cells, IgA synthesis by GM-1056 cells and IgM synthesis by CBL cells in a dose-dependent fashion. This was not a non-specific effect of protein in GH, since equivalent or higher concentrations of proteins such as bovine serum albumin, interleukin-2, interleukin-5, granulocyte/macrophage colony-stimulating factor, or erythropoietin did not stimulate B cell lines. Moreover, the rabbit anti-GH antibody blocked the enhancing effect of GH, while normal rabbit antibody failed to do so. GH also enhanced immunoglobulin synthesis (IgG and IgM) and thymidine uptake by Staphylococcus aureus Cowan strain I-activated tonsil B cells. These results indicate that GH has a direct stimulating effect on B cells, and, in addition to its endocrinological function, GH may also act as an immunoregulatory cytokine.

B-Lymphocytes↗
PubMed1992

Renal handling of urate in two patients with hyperuricemia and primary hyperparathyroidism.

Two patients with primary hyperparathyroidism had hyperuricemia due to the decrease in urate clearance. In analysis by 4-component model system, the tubular secretion of urate commonly decreased without changes in either filtered urate or presecretory reabsorption of urate. Both patients had a reduction of urea clearance, and both parathyroidectomy in the former case and intravenous infusion of saline in the latter case could reduce the serum urate level associated with the increase in the ratio of urate clearance to creatinine clearance. It is of interest that the former case with a higher serum urate level had a relatively higher postsecretory reabsorption, even with the decrease in tubular secretion of urate. However, the latter patient with a lower serum urate level had a decrease in postsecretory reabsorption of urate in proportion to the decrease in tubular secretion. These results suggest that in hyperuricemia patients with primary hyperparathyroidism, the reduction of tubular urate secretion via hypoperfusion of the capillary network is typically present, however, the severity of the hyperuricemia might be dependent on the dysfunction of the postsecretory reabsorption of urate.

Aged↗
PubMed1992

Human B-cell growth-inhibitory activity of eosinophil cationic protein.

The effect of eosinophil cationic protein (ECP) upon proliferation of human B cell lines or purified B cells was studied. ECP inhibited proliferation of the human lymphoblastoid cell lines CBL and GM-1056 at doses of 0.1-5 ng/mL during 2-4 days of culture. The inhibitory effect of ECP was reversible and not due to toxic damage. Moreover, inhibition could be blocked by anti-ECP serum while the control serum failed to do so. Of various cytokines tested--including interleukin (IL)-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6; interferon (IFN)-alpha or IFN-gamma--IL-4 reduced the inhibition, while other cytokines failed to do so. The reduction of inhibition was specific to IL-4 since reduction by IL-4 was blocked by anti-IL-4 antibody but not by the control antibody. ECP also inhibited proliferation of tonsillar small resting B cells stimulated with anti-mu antibody plus low molecular weight B-cell growth factor (BCGF) or of large activated B cells. In contrast, ECP had no effect on proliferation of unstimulated small resting B cells. This inhibition was also reduced by IL-4 specifically. These results indicate that ECP may also act as a B-cell regulating factor.

B-Lymphocytes↗
PubMed1992

[Lupus anticoagulant].

Lupus anticoagulant (LAC) is an acquired inhibitor of prothrombin activator complex, which probably interferes with the phospholipid portion. Characteristically, LAC prolongs the partial prothrombin time, but only slightly prolongs the prothrombin time. It is a paradoxical fact that LAC is characterized by thrombosis. It was initially described in patients with SLE, but recently, it has been described as occurring with other autoimmune disorders. Patients with LAC have been treated with steroid and aspirin, anti platelet agents or warfarin. Steroid and aspirin therapy has been reported useful for habitual abortion associated with LAC. In our study, 11 patients, whose prior pregnancies resulted in habitual abortion (41 abortions), received intentional prednisolone (40 mg/day) and aspirin (81 mg/day) therapy before further pregnancies. The doses of both agents were decreased gradually, and the therapy with prednisolone (10-15 mg/day) and aspirin (40.5 mg/day) was maintained during the pregnancy period. The outcome of pregnancy was successful in 7 out of 10 pregnancies. To evaluate the relationship between LAC and glomerulopathy, we examined the renal biopsy from 5 LAC cases without SLE. In pathological findings, there were 3 of with mild proliferative GN and 2 cases of minor glomerular abnormality. There were no characteristic findings in LAC nephropathy.

Abortion, Habitual↗
PubMed1992

Cyclic AMP-dependent phosphorylation of the rat brain ryanodine receptor.

Phosphorylation of the rat brain ryanodine receptor was studied using a monoclonal antibody, Ry-1, against the cardiac ryanodine receptor. A large polypeptide with the same SDS-PAGE mobility as that of the canine cardiac receptor was detected in rat brain membranes by immunoblotting. The brain ryanodine receptor was solubilized from the microsomal membranes with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS), and more than 85% of the solubilized receptor was immunoprecipitated by Ry-1. Immunoprecipitated receptors were phosphorylated by cAMP-dependent protein kinase. The ryanodine receptor was also expressed in cultured fetal rat brain neurons and was phosphorylated by treating the cells with dibutyryl cAMP. The number of cells showing a caffeine-induced Ca2+ transient was increased significantly in the phosphorylating condition. These results suggest that the Ca channel activity of the brain ryanodine receptor is regulated by cAMP-dependent phosphorylation.

Animals↗
PubMed1992

Infection of Chang cells with hepatitis C virus using hepatic biopsy specimens from patients with chronic hepatitis (type C).

The presence of hepatitis C virus sequence was detected in liver tissue extracts by the polymerase chain reaction (PCR) method using primers of non-coding region in six out of eight cases with chronic hepatitis seropositive for Chiron's antibody. Subsequently, liver extracts from these cases were added to cell cultures of Chang cells for 3 days. The liver extracts of the six cases positive for PCR appeared to infect the Chang cells.

Adult↗
PubMed1992

Urinary coagulation-fibrinolysis, kallirein-kinin systems and kininase in cases of preclampsia.

Urinary kallikrein and kallikrein activity significantly decreased in cases of preeclampsia (u-kall./CRE.index 42.39 +/- 9.66 ng/mg, u-kall. act./CRE.index 0.26 +/- 0.06 ng/min/mg), and urinary kininase II and kininase activity significantly increased (u-kininase/CRE.index 10.91 +/- 1.26 x 10(-3) IU/min/mg, u-kininase act./CRE.index 506.37 +/- 178.45 pg/min/mg) when compared with those of normal gravidas from 28 weeks to 42 weeks of gestation (u-kall./CRE.index 189.31 +/- 14.17 ng/mg, u-kall. act./CRE index 1.08 +/- 0.10 ng/min/mg, u-kininase/CRE.index 6.24 +/- 0.31 x 10(-3) IU/min/mg, u-kininase act./CRE.index 15.64 +/- 0.10 pg/min/mg). Urinary FPA, B beta 5-42, alpha 2-PI, and alpha 2PI-plasmin-complex (PIC) significantly increased in preeclampsia (u-FPA/CRE.index 23.59 +/- 8.47 ng/mg, u-B beta/CRE.index 105.26 +/- 29.30 ng/mg, u-alpha 2PI/CRE.index 121.53 +/- 43.57 ng/mg, u-PIC/CRE index 278.39 +/- 60.50 ng/mg) when compared with those of normal control group (u-FPA/CRE.index 0.92 +/- 0.04 ng/mg, u-B beta/CRE.index 12.15 +/- 0.44 ng/mg, u-alpha 2PI/CRE.index 4.18 +/- 0.33 ng/mg, u-PIC/CRE.index 5.98 +/- 1.15 ng/mg). Urinary urokinase markedly increased and urinary D-dimer was detected in severe cases of preeclampsia (u-UK/CRE.index 58.20 +/- 43.69 ng/mg, u-D-dimer 54.76 +/- 9.89 ng/ml) when compared with those of normal control group. These findings suggest that deficiency in urinary kinin excretion may induce hypertension in addition to the changes of urinary coagulation-fibrinolysis system that represents the occurrence of either the endothelial cell injury in the glomerulus or the renal tulbular damage in mild cases of preeclampsia, eventually resulting in the intra-renal vascular coagulation.

Female↗
PubMed1992

Stimulation of corticosterone secretion by dietary histidine in rats.

1. Liver glycogen accumulated within 3 days after the initiation of a histidine-excess diet. Serum corticosterone increased and serum insulin decreased, but plasma glucagon remained unchanged. 2. When 2 mmol (310 mg) of histidine was administered to fasted rats, serum corticosterone increased after 5 hr and tended to be higher 9 hr after administration. 3. Liver glycogen tended to accumulate after 5 hr and had accumulated significantly after 9 hr.

Adrenal Glands↗