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Biomedical subjects

T Kim

Publications and source records attributed to T Kim.

At least 217 records · Page 12Linked to original sources
PubMed1992

[Image-transmission using 64 kbps-ISDN (Integrated Services Digital Network) and mini-PACS].

We carried out the image-transmission using 64kbps-ISDN between two image workstations (IWS) of mini-PACS installed at the Department of Radiology, Osaka Teishin Hospital and the Kashiwa Works, Hitachi Medical Corporation. The distance between Osaka and Kashiwa is about 600 km. The subtraction of two images before and after transmission revealed no change of the data of the image during transmission. For 1/2 compression image, the times of image-transmission of 256 x 256, 320 x 320 and 512 x 512 matrix were 9, 17 and 33 second, respectively. The efficiency of image-transmission was about 80%. Using ISDN, we can make an accurate, rapid and cheap image-transmission.

Computer Communication Networks↗
PubMed1992

Expression of protease nexin-II in human dorsal root ganglia. A correlative immunocytochemical and in situ hybridization study.

Protease nexin-II (PN-II) is a potent chymotrypsin inhibitor that forms SDS-stable inhibitory complexes with epidermal growth factor binding protein, the gamma-subunit of nerve growth factor, and trypsin, and represents the secreted form of the amyloid beta-protein precursor (APP) that contains the Kunitz-type protease inhibitor domain. To determine the expression of PN-II within the peripheral nervous system, human dorsal root ganglia were processed for immunocytochemistry using well-characterized monoclonal antibodies against PN-II and for in situ hybridization studies using 35S-RNA PN-II probes for both APP751 and APP770. Highly specific immunoperoxidase staining of PN-II was demonstrated within the cytoplasm of dorsal root ganglia neurons and their processes in cryostat (fresh frozen) and vibratome (paraformaldehyde-fixed) sections. In situ hybridization using an anti-sense 35S-RNA PN-II probe demonstrated the presence of intense neuronal labeling. Labeling was not observed when the corresponding sense 35S-RNA PN-II probe was used. Although the precise functional role of PN-II/APP is not clear, the accumulation of amyloid beta-protein within the neuropil appears to be one of the earliest events in the pathogenesis of Alzheimer's disease (AD). Thus knowledge of the cell populations expressing the PN-II/APP gene would certainly be helpful for studies of the molecular mechanisms leading to the morphological and functional changes of AD. The results of this study clearly establish the expression of PN-II and its mRNA within the dorsal root ganglia neurons and their processes, and provide another point of departure for studies of the molecular mechanisms underlying the deposition of amyloid beta-protein and its relationships to the formation of neuritic plaques and neurofibrillary tangles.

Amyloid beta-Protein Precursor↗
PubMed1992

The effect of contaminant source momentum on a worker's breathing zone concentration in a uniform freestream.

Several factors affecting breathing zone concentration were examined in a paint spray booth by using a tracer gas method. The variables in the study include contaminant momentum, the presence of a flat plate downstream of the worker, the distance between the contaminant source and the body, and the worker's motion. A dramatic reduction in breathing zone concentration was observed when the spray gun emitted contaminants with high momentum. Reductions of 30-50% were observed because of the other variables. The source momentum effect was studied, subsequently, in a wind tunnel by measuring the breathing zone concentration of a mannequin with various flows through jets of different diameter, at varying freestream velocities. A functional relationship was determined between nondimensional breathing zone concentration and contaminant source momentum. This relationship is supported by numerical simulations. The effect of contaminant momentum on the near-wake flow field is discussed in conjunction with results from the numerical simulations.

Air Movements↗
PubMed1992

Blockade of natural and neuropeptide Y-induced carbohydrate feeding by a receptor antagonist PYX-2.

Neuropeptide Y (NPY injected into the paraventricular nucleus (PVN) of rats has a potent stimulatory effect specifically on carbohydrate intake. This study examined the behavioral effects of a newly synthesized NPY antagonist, PYX-2. After PVN injection of PYX-2 (50-900 pmoles) alone, a strong dose-dependent reduction in spontaneous carbohydrate intake at the onset of the dark cycle was observed in freely-feeding rats. Moreover, at even lower doses (12.5 and 25.0 pmoles), PYX-2 also blocked the stimulatory action of PVN NPY (100 pmoles) on carbohydrate ingestion. These results provide the first evidence for the existence of endogenous NPY receptors in mediating the action of exogenous NPY in the hypothalamus. They also constitute a crucial step in demonstrating a physiological function of these PVN NPY receptors specifically in controlling carbohydrate ingestion at the onset of the natural feeding cycle.

Anesthesia↗
PubMed1992

Effect of ciclosporin on cardiac output and regional blood flow in rats: ciclosporin-induced nephropathy and its prevention with calcium channel blocker.

The effect of ciclosporin (CS) on cardiac output (CO) and regional blood flow was studied using the microsphere method in heminephrectomized rats with and without renal arterial clamping prior to the administration of CS. The effect of a calcium (Ca) channel blocker, verapamil, was also examined on CS-induced nephropathy. CS at a dose of 40 mg/kg per day was given orally using a gastric tube for 7 days. Verapamil was given in the drinking water for 7 days. Significant increases in blood urea nitrogen (BUN) and serum creatinine (sCr) with a significant decrease in renal inulin clearance (CIn) were noted after 7 days of CS administration in both intact and ischemic-kidney groups, indicating the development of CS-induced nephropathy. The ischemic-kidney group showed a significantly severe nephropathy as compared with the intact-kidney group. As for change in CO and regional blood flow, CS caused a significant decrease in CO, renal blood flow (RBF) and brain blood flow, while hepatic arterial blood flow and muscular blood flow significantly increased. The renal outer cortical blood flow decreased markedly while the inner cortical blood flow remained unchanged. Although verapamil slightly but significantly decreased mean arterial blood pressure in CS-treated rats, CO and its distribution did not change. BUN and sCr were not significantly ameliorated in the intact-kidney group. However, in the ischemic-kidney group, verapamil caused a significant improvement in RBF, ameliorating CS-induced elevation of BUN and sCr, and a decrease in CIn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Determination of the acid dissociation constants for WR-1065 by proton NMR spectroscopy.

The acid dissociation constants for N-(2-mercaptoethyl)-1,3-diaminopropane (WR-1065) were determined in D2O by 360- and 500-MHz NMR spectroscopy. Results obtained at 0.21 M initial ionic strength and 26 degrees C were corrected to 25 degrees C yielding pKD1 = 8.28 +/- 0.04, pKD2 = 9.88 +/- 0.07, and pKD3 = 11.58 +/- 0.03. Correction of these values for the effect of the deuterium isotope upon the ionization reaction yielded dissociation constants in water of pKH1 = 7.69 +/- 0.09, pKH2 = 9.35 +/- 0.09, and pKH3 = 11.10 +/- 0.08. Analysis of the changes in chemical shift with pD indicated that the first ionization occurs largely through ionization of the thiol group (approximately 67%) and to a lesser extent the secondary ammonium group (approximately 30%), whereas the third ionization involves mainly the secondary ammonium group (approximately 65%) and to a lesser extent the primary ammonium group (approximately 30%). Estimates of the microscopic pK values for WR-1065 were also obtained from the results.

Hydrogen-Ion Concentration↗
PubMed1991

Secondary hemorrhage in traumatic hyphema.

We analyzed the records of 132 patients hospitalized between July 1986 and February 1989 for management of traumatic hyphema. The incidence of secondary hemorrhage was compared between patients treated with or without systemic administration of aminocaproic acid in addition to an otherwise identical protocol. Results among patients who were examined within one day of injury disclosed a 4.8% secondary hemorrhage rate in aminocaproic acid-treated patients (three of 63 patients) compared with a 5.4% rate in the patients not treated with aminocaproic acid (three of 56 patients, P = .31). All six patients sustaining secondary hemorrhage recovered visual acuities of 20/40 or better, with five of six patients achieving 20/20 visual acuities. A separate group of 13 patients who were examined more than one day after injury were found to have a secondary hemorrhage rate of 38.5% (five of 13 patients). Macular injury, not secondary hemorrhage, was most often responsible among those patients suffering permanent visual loss. In this study of a predominantly white population, patients had a relatively low incidence of secondary hemorrhage and did not demonstrate detectable benefit from aminocaproic acid administration. Because of the recognized side effects and cost of treatment, further analysis to determine which patients will benefit from treatment with aminocaproic acid is indicated.

Adolescent↗
PubMed1991

Effects of adrenalectomy on macronutrient selection patterns in the rat.

The present studies examined the effects of adrenalectomy (ADX) on nutrient selection of rats over the 24-h period, as well as during the first 2 h of the nocturnal feeding cycle. Results indicate that ADX, in rats showing generally similar preferences for carbohydrate and fat, equally suppresses intake of both of these nutrients over the 24-h period. The relative impact of ADX on carbohydrate and fat intake may shift depending upon baseline, with carbohydrate-preferring rats showing a stronger decrease in intake of this diet after ADX and fat-preferring rats exhibiting a greater decline in fat intake after ADX. Acute injections of corticosterone (CORT) and aldosterone (ALDO) are both found to restore carbohydrate as well as fat intake to ADX rats over the 24-h period. However, in the first 2 h of the dark feeding cycle, carbohydrate intake is found to be selectively suppressed after ADX, and CORT injection (0.5 and 2.0 mg/kg, SC) restores carbohydrate intake during this early dark period, while producing a small increase in fat intake only at the higher dose. This is in contrast to ALDO administration at dark onset, which has a stronger stimulatory effect on fat intake in the ADX rat but does not fully restore carbohydrate intake. These findings indicate that CORT and ALDO have differential effects on nutrient intake in ADX rats particularly at the onset of the dark cycle, and it is suggested that these effects are mediated, respectively, by the type I and type II steroid receptor systems in the brain.

Adrenal Glands↗
PubMed1991

Airflow pattern around a worker in a uniform freestream.

The effect of boundary layer separation on worker exposure is an important factor in the design of local exhaust ventilation. Three-dimensional airflow around a mannequin is examined by using flow visualization techniques and hot-film anemometry. Above the chest, a downwash effect is noted; from the chest to the elbows, a combination of downwash and vortex shedding is observed; and from the waist to the hip, vortex shedding appears to be dominant. A coherent vertical flow structure is observed close to the body. Vortex shedding frequency is determined by using hot-film anemometry. The dimensions of the reverse flow region and the area of the vortices are estimated from flow visualization videos.

Humans↗
PubMed1991

Modeling a worker's exposure from a hand-held source in a uniform freestream.

The phenomenon of boundary layer separation can be an important factor in determining a worker's exposure to toxic airborne pollutants. A conceptual model was developed to understand this phenomenon and to predict the average concentration in the reverse flow region downstream of a worker in a uniform freestream. Subsequently, the assumptions of this model were tested experimentally in wind tunnel studies. On the basis of these results, a revised model is presented and validated by using a tracer gas method. The revised model provides a reasonable estimate of the average concentration in the reverse flow region of the mannequin. Empirical models are presented that relate both the average concentration in the reverse flow region and the breathing zone concentration to the body dimensions and the freestream air velocity. Applications and limitations of the results are discussed.

Air Movements↗
PubMed1991

Human complement component factor B rescues HIV-1-infected leukemic T cells from cytopathic death.

The addition of 5-10% of fresh normal human serum (NHS) from normal individuals into a culture of primarily HIV-1-infected CD4+ leukemic T-cell lines CEM and MT4 was found to rescue the infected cells from cytopathic death, enabling the cells to achieve growth within 10 days. The HIV-1-infected cells cultured in ordinary medium with fetal calf serum (FCS) all died within 10 days. The effect of NHS was ascribed to human complement component factor B and one or more factor B-dependent heat-labile co-factors. The cells which survived in the presence of NHS rapidly lost surface expression of CD4 and became completely resistant to rechallenge by HIV-1. Viral genomes were dramatically reduced in surviving cells within 30 days, and one cell-line CEM completely expelled them during this period. The results suggest that factor B has protective and potential therapeutic significance in HIV-1 infection.

CD4 Antigens↗
PubMed1991

Autonomic regulation of subsidiary atrial pacemakers during exercise.

Cardiac responses to graded treadmill exercise were compared in conscious dogs before and after excision of the sinoatrial node (SAN) and adjacent tissue along the sulcus terminalis. The chronotropic and dromotropic responses to dynamic exercise were compared with and without selective muscarinic (atropine) and/or beta-adrenergic (timolol) blockade. With the SAN intact, cardiac acceleration was prompt during onset of exercise and in proportion to work intensity. Immediately after SAN excision (1-7 days), pacemaker activity exhibited marked instability in rate and pacemaker location, with rapid shifts between atrial and junctional foci. Soon thereafter (1-2 wk), subsidiary atrial pacemakers (SAPs) assumed the primary pacemaker function. Although the SAP foci demonstrated stable heart rates and atrioventricular (AV) intervals at rest and during exercise, heart rates at rest and during steady-state exercise were reduced 34% from corresponding levels in the SAN-intact state, both with and without selective autonomic blockade. For control of dromotropic function, animals with SAP foci showed pronounced shortening in AV interval in conjunction with exercise that was further exacerbated by pretreatment with atropine. Eight weeks after excision of the primary SAN pacemakers, direct electrophysiological mapping localized the SAP foci to either the inferior right atrium along the sulcus terminalis or the dorsal cranial right atrium (in or near Bachmann's bundle). Animals with SAPs localized to the inferior right atrium had a more marked suppression in heart rate with a corresponding greater decrease in AV interval during exercise than dogs with SAP foci identified within the dorsal cranial right atrium.

Animals↗
PubMed1991

[Effects of verapamil on cyclosporine. A (CsA)-induced nephropathy in ischemic kidney model in rats: changes in systemic hemodynamics and hepatic and renal microsomal cytochrome P-450].

We have examined the effect of verapamil on CsA-induced nephropathy by measurement of systemic hemodynamics including each organ blood flow using the microsphere method in ischemic kidney model of hemi-nephrectomized Wistar rats. Hepatic and renal microsomal cytochrome P-450 contents and their enzyme activities were measured to study the correlation between CsA-induced nephropathy and induction of hepatic and renal microsomal cytochrome P-450. All rats were hemi-nephrectomized (l-nephrectomy) and were classified into the following 6 groups: 1) control groups, 2) CsA at a dose of 40 mg/kg per day orally for 7 days (CsA group), 3) Oral administration of verapamil for 7 days in the CsA group (CsA + V group), 4) 20 min clamping of the remaining right kidney pedicle (Ischemic, Is group), 5) CsA was administered in the Is group (Is + CsA group), 6) Addition of verapamil to CsA in the Is + CsA group (Is + CsA + V group). Verapamil was given in the drinking water and the average dose calculated from the amount of drinking was 4.7 +/- 1.0 mg/kg per day and 5.2 +/- 0.7 mg/kg per day for the CsA + V group and the Is + CsA + V group, respectively. CsA caused significant increases in BUN and serum creatinine (sCr) with a significant decreases in renal inulin clearance (CIn) in all groups. When compared with the Is group, CsA caused significant decreases in cardiac output and all organ blood flow especially in renal blood flow with significant increases in BUN and sCr in the Is + CsA group.2+ degree of nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Bone marrow transplantation for advanced acute leukemia: a pilot study of high-energy total body irradiation, cyclophosphamide and continuous infusion etoposide.

Leukemic relapse following bone marrow transplantation (BMT) for acute leukemia is the most common cause of treatment failure. Because a more intensive pre-transplant preparative regimen may prevent disease recurrence we have designed a novel intensive conditioning regimen for BMT using high-energy total body irradiation (total dose 850 cGy; energy 24 MV; midplane received dose rate 26 cGy/min; day -6) followed by cyclophosphamide (dose 50 mg/kg/day; schedule 2-h infusion; days -5, -4, -3) and continuous infusion high-dose etoposide (dose 500 mg/m2/day; schedule: 22-h infusion; days -5, -4, -3). Between February 1987 and December 1988, 45 patients with advanced acute leukemia received transplants using this regimen. Twenty-five purged auto-transplants were done for B-lineage (n = 18), T-lineage (n = 6) or biphenotypic (n = 1) acute lymphoblastic leukemia, with 12 in remission and 13 in relapse at the time of transplantation. Of these, nine had non-relapse deaths and 16 have relapsed between 1 and 19 months (median 3 months) following transplantation. Of note all the T-lineage patients relapsed including two transplanted in remission and five transplanted in relapse. Nineteen patients received histocompatible allogeneic transplants and one underwent syngeneic transplantation. Of seven patients with acute lymphoblastic leukemia transplanted in refractory relapse, three have had an overt relapse, three died of interstitial pneumonitis and only one survives disease free 15 months after transplantation. Of 13 patients with acute non-lymphocytic leukemia and variants (11 who were transplanted in relapse) three died without relapse, three have relapsed and seven survive disease free from 9 to 27 months (median 20 months) after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗