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Biomedical subjects

K Miki

Publications and source records attributed to K Miki.

At least 397 records · Page 22Linked to original sources
PubMed1986

Immunoblotting analysis of plasma protein processing in the secretory pathway of rat liver: identification of proteolytic conversion sites of complement pro-C3 and prohaptoglobin.

Using an immunoblotting technique, we have studied the processing of plasma proteins in subcellular fractions of rat liver including rough and smooth microsomes and the Golgi subfractions. Each subcellular fraction was directly subjected to SDS-polyacrylamide gel electrophoresis and analyzed by immunoblotting with antibodies against alpha 1-protease inhibitor, haptoglobin, and the third component of complement (C3) in combination with 125I-protein A or 125I-rabbit anti-(goat IgG)-IgG. The results demonstrated that proteolytic processing of precursors of complement C3 and haptoglobin occurs in different compartments along the secretory pathway; conversion of prohaptoglobin takes place in the endoplasmic reticulum, while that of pro-C3 occurs in the Golgi complex. The processing in oligosaccharide chains of glycoproteins was also analyzed. The Golgi fraction was characterized by the presence of the mature 56 kDa alpha 1-protease inhibitor, which was indistinguishable from the serum alpha 1-protease inhibitor in SDS-polyacrylamide gel electrophoresis. In contrast, the immature 51 kDa form was the only form of alpha 1-protease inhibitor found in the microsomal fraction. Similar results were obtained for the beta subunit of haptoglobin; the immature 33 kDa form was detected in the microsomal fraction, while the mature 36 kDa form was found in the Golgi fraction. Taken together, these results identified the intracellular sites where these plasma proteins are modified by selective proteolysis and/or glycosylation.

Animals↗
PubMed1986

Peripheral circulatory responses to 96 h of hypoxia in conscious sinoaortic-denervated sheep.

Conscious sheep exposed to 4 days of eucapnic hypoxia (arterial PO2 40 Torr, arterial PCO2 33 Torr) respond with sustained increases in heart rate, cardiac output, and coronary, cerebral, and respiratory muscle blood flows (Respir. Physiol. 59: 197-211, 1985). In the present investigation, seven adult ewes were studied during similar levels of hypoxia (arterial PO2 40 Torr, 4 days) after chronic section of the carotid sinus and aortic depressor nerves to determine the contribution of the arterial chemoreceptors to these responses. Ventilation and arterial PCO2 did not change, indicating that ventilatory acclimation did not occur. O2 consumption decreased by 24%. Cardiac output (thermodilution) increased by 12% for only 24 h, heart rate increased by 44-69% above normoxic levels for only 72 h, and stroke volume was unchanged. Systemic arterial pressure was unchanged, whereas pulmonary arterial pressure rose by 56%. Coronary flow (radio-labeled microspheres) increased from 155 +/- 50.4 (SE) to 299 +/- 81 ml X min-1 X 100 g-1 at 24 h and then declined to normoxic levels by 96 h. Cerebral flow rose from 62 +/- 6.5 to between 85 +/- 14.4 and 124 +/- 43.5 ml X min-1 X 100 g-1 for 96 h. These results indicate that the arterial chemoreflexes or reflexes secondary to increased ventilation are responsible for the continued elevation of heart rate, cardiac output, and coronary flow during eucapnic hypoxia.

Animals↗
PubMed1986

Plasma volume changes during head-out water immersion in conscious dogs.

Blood volume (51Cr-erythrocyte dilution method), hematocrit, and arterial (Pa), central venous (Pv), plasma colloid osmotic (IIpl), and interstitial fluid hydrostatic (Pcps, Guyton's capsule method) pressures were measured continuously to determine the kinetics of the transvascular fluid shift during 100 min of water immersion (WI) at 37 degrees C in six splenectomized dogs. Urine flow increased by 180% above control levels (P less than 0.05) by 30 min of WI. Plasma volume (PV) started to increase at 5 min of WI and rose by 7.2% (P less than 0.05) above control levels by 35 min of WI, and then it decreased gradually. PV returned to control levels immediately after WI. Plasma protein concentration and IIpl decreased significantly by 0.2 g/100 ml and 1.2 mmHg, respectively, at 35 min of WI, while plasma osmolality and Na+ concentration were constant. Pa and Pv increased (P less than 0.05) by 25 and 12 mmHg, respectively. Mean capillary pressure, which was calculated from Pa, Pv, and an estimated pre-to-postcapillary resistance ratio of 5-12, increased by 13-14 mmHg while Pcps increased (P less than 0.05) by 17 and 26 mmHg at upper hindlimb and lower forelimb, respectively. The changes in mean capillary pressure and IIpl tend to promote capillary filtration in WI; however, the greater elevation of Pcps more than offsets these forces and leads to a net transvascular shift into the plasma compartment.

Animals↗
PubMed1986

Atrial natriuretic factor and renal function during head-out water immersion in conscious dogs.

The potential role of atrial natriuretic factor (ANF) in the renal response to head-out water immersion (WI) was studied. Five female mongrel dogs, trained to stand for 100 min in air followed by 100 min of thermoneutral WI at 37 degrees C or 200 min in air (timed control, TC), were chronically instrumented with arterial and venous catheters. The animals were hydrated with a volume of 0.45% NaCl solution equivalent to 2% of their body weight. Prehydration levels of arterial ANF were 243 +/- 15 (SE), and venous ANF levels were 211 +/- 21 pg/ml. WI resulted in an increase in urine flow from 0.7 +/- 0.1 ml/min to a peak flow of 2.2 +/- 0.3 ml/min (P less than 0.05). On immersion, plasma venous and arterial ANF levels increased significantly by 29 and 21% from the preimmersion values of 183 +/- 14 and 222 +/- 20 pg/ml, respectively. The arterial-venous difference for plasma ANF was maintained at 35 +/- 14 pg/ml (P less than 0.05) during WI; therefore venous sampling may suffice as a measure of circulating ANF levels. Sodium excretion increased linearly during WI to a peak value of 228 +/- 32 mu eq/min from a base line of 52 +/- 12 mu eq/min (P less than 0.05). These data indicate that peripheral tissues extract ANF and that WI is a physiological stimulus for the release of ANF. However, the time course and magnitude of the changes in plasma ANF and urine sodium excretion during WI are not comparable, and other mechanisms are likely responsible for the WI natriuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Gastric and intestinal phenotypic expressions of human signet ring cell carcinomas revealed by their biochemistry, mucin histochemistry, and ultrastructure.

Gastric and intestinal phenotypic expression in 37 surgically obtained primary signet ring cell carcinomas, five of their metastases to lymph nodes, and three signet ring cell carcinomas transplanted into nude mice were determined by biochemical, mucin, histochemical, and ultrastructural studies. Crude extracts of cancer tissues were used for measurements of pepsinogen isozymes, sucrase, aminopeptidase (microsomal), and alkaline phosphatase. Histochemical staining of mucin by paradoxical concanavalin A, the galactose oxidase-Schiff sequence and sialidase-galactose oxidase-Schiff, and the periodate-borohydride technique/potassium hydroxide/periodic acid-Schiff procedure was performed. The procedures allowed clear definition of pyloric gland, surface mucous, small and large intestinal goblet, and intestinal absorptive cell types. Of 40 specimens examined, 19 consisted entirely of gastric-type cells, and three entirely of intestinal-type cells. The others consisted of mixtures of gastric and intestinal-type cells. The observed high incidence of intestinal-type cells in signet ring cell carcinomas suggested that intestinal-type cells develop independently from intestinal metaplasia within signet ring cell carcinomas (diffuse-type gastric cancers), which probably originate from nonmetaplastic gastric mucosa.

Adenocarcinoma, Mucinous↗
PubMed1985

Multiple molecular forms of diarylpropane oxygenase, an H2O2-requiring, lignin-degrading enzyme from Phanerochaete chrysosporium.

Three different molecular forms of the H2O2-requiring heme enzyme, diarylpropane oxygenase, were isolated from the extracellular medium of Na-acetate buffered, agitated cultures of Phanerochaete chrysosporium. Forms I, II, and III were separated by DEAE-Sepharose and further purified on Sephadex G-100. Absorption maxima of the native, reduced, and a variety of ligand complexes of the three enzyme forms are essentially identical, indicating similar heme environments. All forms also have similar, but not identical, reactivity. The homogeneous proteins oxidized a diarylpropane, an olefin, a beta-aryl ether dimer, a phenylpropane, phenylpropane diols, and veratryl alcohol. Identical products were produced from each form. However, the specific activities of the three homogeneous enzymes for veratryl alcohol oxidation were 18.75, 11.80, and 8.48 mumol min-1 mg-1. In the presence of one equivalent of H2O2 the Soret maximum of diarylpropane oxygenase II shifted from 408 to 418 nm, and two additional maxima appeared at 526 and 553 nm, indicating the presence of an Fe(IV)-oxo species equivalent to horseradish peroxidase II. This oxidized species could be reduced back to the native form by veratryl alcohol and several reducing agents (e.g., Na2S2O4, NH2NH2, thiourea, or NADH). The molecular weights of diarylpropane oxygenases I, II, and III were approximately 39,000, 41,000, and 43,000, respectively. The major form (II) (85% of the activity) contained approximately 6% neutral carbohydrate. The affinity of the forms for concanavalin A-agarose suggests that they all are glycoenzymes.

Basidiomycota↗
PubMed1985

Effects of intravitreal administration of steroids on experimental subretinal neovascularization in the subhuman primate.

To elucidate the role of inflammation in the occurrence of experimental subretinal neovascularization caused by high-intensity laser photocoagulation, we investigated the effects of vitreal infusion of steroids on laser lesions in a primate model. Dexamethasone, with or without triamcinolone, was infused continuously for two weeks through an indwelling cannula system. The animals were followed up clinically for up to eight weeks. The frequency of subretinal neovascularization in the steroid-treated animals was significantly lower than that in a control group of untreated animals. Although steroids have multiple effects, these results suggest that the inflammatory response, possibly macrophage infiltration, may plan an important role in the occurrence of subretinal neovascularization in our experimental model.

Animals↗
PubMed1985

Intraocular cannula for continuous, chronic drug delivery. Histopathologic observations and function.

An indwelling cannula for drug delivery was implanted in rabbit eyes. Rabbits were followed up for as long as 1 1/2 years after surgery. They showed almost no adverse effects as a result of the implantation, and cannula patency was demonstrated by the injection of fluorescein sodium through the cannula at various times following surgery. Histopathologic studies using light and electron microscopy were performed at various times to determine the effect of cannula implantation on the eye. Cellular proliferation along the cannula after 1 1/2 years was limited to the region immediately adjacent to the wound and rarely extended to the surrounding retina or ciliary body. The proliferative tissue at the wound site originated mainly from the episclera; the retina and the choroid at the posterior fundus remained intact. Photoreceptor cell metabolism was studied by light microscopic autoradiography following intraocular injection of tritiated leucine to assess photoreceptor outer-segment renewal. Autoradiography showed normal receptor uptake of leucine. A broad band of radioactive labeling of the outer segments resulted from continuous, chronic drug delivery, while a narrow band of labeling resulted from a single intravitreous injection. These data indicate that the cannula system continuously delivered tritiated leucine into the vitreous cavity. We believe that the implanted intraocular cannula, which allows continuous drug delivery on a relatively long-term basis, will be a valuable technique for research and possibly clinical studies.

Animals↗
PubMed1985

Intraocular cannula for chronic drug delivery. Method and clinical observation.

An intraocular cannula system for chronic drug delivery was designed and tested in rabbits. The cannula was inserted through the pars plana and the tip positioned in the vitreous cavity (distal tip) in a site close to the retinal area of interest. The cannula was stabilized by a silicone plate that was sutured to the sclera. The proximal end of the cannula was attached to a larger diameter silicone tubing which served as a connector to the reservoir for chronic drug delivery. Rabbit eyes with implanted cannulas were followed clinically and electrophysiologically for up to one and a half years. They showed almost no adverse effects as a result of the implantation and cannula patency was demonstrated by the injection of sodium fluorescein through the cannula at various times following surgery. We believe that the implanted intraocular cannula, which allows chronic drug delivery, will be a valuable asset for research and possibly clinical studies.

Animals↗
PubMed1985

Peripheral circulatory responses to 96 hours of eucapnic hypoxia in conscious sheep.

Conscious sheep acclimatizing to hypoxia (PaO2 40 mm Hg, PaCO2 24 mm Hg) respond with increases in cardiac output (Qco) and cerebral blood flow lasting for 24 and 48 h, respectively. Coronary flow increases in a sustained fashion, while there are progressive decreases in renal, splenic and pancreatic flows. In the present study, 5 adult ewes were exposed to similar levels of normobaric hypoxia (PaO2 40 mm Hg) but the PaCO2 was maintained at eucapnic levels (32 mm Hg). VE increased (+210%) while VO2 decreased by 35%. Ventilatory sensitivity to CO2 was unchanged. Qco (thermodilution) was elevated for 96 h (+20%) as stroke volume was maintained at normoxic levels and heart rate increased (+36%). Pulmonary artery pressure increased (+35%) along with plasma catecholamine levels (+116-196%). There were sustained elevations of cerebral flow (radiolabelled microspheres) from 79.1 (+/- 9.2 SEM) to 121.6 ml X min-1 X 100 g-1 (+/- 10.8), coronary flow from 183 (+/- 22.1) to 373 ml X min-1 X 100 g-1 (+/- 46.3), diaphragm flow (+400%) and intercostal muscle flow (+186%) with no apparent redistribution of Qco. Therefore, the cardiac and peripheral circulatory response patterns are altered significantly in eucapnic hypoxia. The rate of O2 delivery to brain and several abdominal viscera is higher.

Animals↗
PubMed1985

An indwelling cannula system for the primate eye.

An indwelling cannula system was designed as an instrument for chronic drug infusion into the vitreous cavity and tested in the cynomolgus monkey eye with repeated injections or continuous infusion using a pumping device. The cannula was passed through the pars plana and its tip situated in the vitreous cavity close to the macular area. Clinical observations up to 18 months did not reveal any adverse effects due to implantation. Histopathological observations from 1 week to 18 months after surgery revealed tissue proliferation around the cannula was minimal and localized only at the wound site, where proliferative tissue originated from the episclera and ciliary epithelium. Retina and choroid at the posterior pole showed normal morphology. Light microscopic autoradiograms demonstrated the function of this system. Injections of tritiated leucine through the cannula resulted in narrow bands of radioactive labelling of the photoreceptor outer segments corresponding to each injection. In contrast, chronic delivery using the pumping device resulted in a diffuse and wide band of labelling. These results strongly suggest that this system did not adversely affect the eye and that repeated intravitreal injections or chronic drug delivery into the vitreous are feasible using this system. Furthermore, autoradiographic results suggest that the drugs infused into the vitreous cavity spread readily into the retina.

Animals↗
PubMed1985

Cholagogic effect of ginger and its active constituents.

The effect of bile secretion in rats was examined in order to clarify the stomachic action of ginger and also to investigate its active constituents. The results showed that mainly the acetone extracts of ginger, which contain essential oils and pungent principles, caused an increase in the bile secretion. Further analyses for the active constituents of the acetone extracts through column chromatography indicated that [6]-gingerol and [10]-gingerol, which are the pungent principles, are mainly responsible for the cholagogic effect of ginger.

Animals↗
PubMed1985

Spontaneous glomerular IgA deposition in ddY mice: an animal model of IgA nephritis.

It was found that ddY mice derived from non-inbred dd-stock mice brought from Germany before 1920 and then raised in Japan developed spontaneously IgA dominant deposition in the glomerular mesangium. In this report we give a detailed natural history of the renal pathology of those mice. The animals were fed rodent laboratory chow and sacrificed in groups of 9 to 10 at 6, 10, 16, 24, 28, 40, and 59 weeks of age. The bladder urine was analyzed, serum immunoglobulins were measured, and the kidney specimens were evaluated with light, fluorescent, and electron microscopy. Proteinuria was (plus) to (2 plus) after 28 weeks and (2 plus) to (3 plus) at 59 weeks with negative hematuria. Mesangial cell proliferation began to appear at 16 weeks, then progressed to a definite proliferative glomerulonephritis. At 59 weeks an additional increase of the mesangial matrix occurred. By immunofluorescence, there were IgG of (2 plus), IgM (plus) to (2 plus), IgA (plus) and C3 (plus) in the glomeruli until 28 weeks. However, IgA started to be dominant at 40 weeks and the glomerular pattern was IgA (2 plus) to (3 plus), IgG (plus) to (2 plus), IgM (+/-) to (plus) and C3 (plus) to (2 plus) at 59 weeks. Polyclonal IgA and IgG2a among immunoglobulins steeply rose at 40 weeks, and at 59 weeks IgA increased by 850%, IgG2a by 280%, IgG1 by 170%, IgG2b by 90%, and IgM by 60%, as compared with their level at 6 weeks. There was no anti-nuclear antibody. Thus, ddY mice, at least after the age of 40 weeks, can be used as a new animal model for spontaneous IgA nephritis. The probable origin of IgA is also discussed.

Animals↗
PubMed1985

Gene structures of low-neurovirulent vaccinia virus LC16m0, LC16m8, and their Lister original (LO) strains.

Vaccinia viruses LC16m0 and LC16m8 are temperature-sensitive and low-neurovirulent variants derived from the Lister (Elstree) (LO) strain. Analyses of genome DNAs by digestion with restriction endonucleases and cross-hybridization of the digested fragments revealed that LC16m0 and LC16m8 possess a new XhoI site in addition to the 14 XhoI sites of LO. This new site is located at about 12 X 10(6) daltons from the right terminal end. There was no significant difference in the genome structures between the LC16 variants and LO except the new XhoI site and their terminal fragments which were not identified in LO owing to their heterogeneity. With HindIII digested fragments, there was no difference among the three viruses. This complete mapping raised the possibility that the putative gene responsible for temperature sensitivity and neurovirulence is located at the region of the XhoI site found in LC16m0 and LC16m8.

Cloning, Molecular↗
PubMed1985

Serum ferritin as a marker of thyroid hormone action on peripheral tissues.

Serum ferritin measurements were evaluated as a marker of thyroid hormone action on peripheral tissues. Mean serum ferritin concentrations were not significantly different in euthyroid, thyrotoxic, and hypothyroid subjects due to a wide spread in ferritin levels among individuals. Intraindividual changes in serum ferritin, however, occurred with changing thyroid function. All 18 patients with thyrotoxic Graves' disease had a decrease in serum ferritin levels when they became euthyroid during antithyroid drug therapy. Furthermore, a significant intraindividual correlation between serum levels of ferritin and T4 or T3 was found in 2 patients with thyrotoxic Graves' disease in whom levels were measured serially throughout the course of therapy. Similarly, serum ferritin levels increased in all 12 hypothyroid patients with Hashimoto's disease when euthyroidism was achieved with L-T4 therapy. Administration of 75 micrograms T3 daily for 1 week to 11 euthyroid subjects resulted in a 23-243% (mean +/- SD, 117 +/- 70%) increase in serum ferritin above basal values. In contrast, in 3 patients with thyroid hormone resistance, the same treatment produced rises in serum ferritin concentrations of only 2%, 5%, and 15%. Our data suggest that alterations in thyroid status in a given individual produce changes in serum ferritin levels. Measurement of this protein before and after T3 therapy may prove useful in the diagnosis of thyroid hormone resistance.

Adult↗