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Biomedical subjects

A Kim

Publications and source records attributed to A Kim.

At least 55 records · Page 3Linked to original sources
PubMed2000

Blood fatty acid composition of pregnant and nonpregnant Korean women: red cells may act as a reservoir of arachidonic acid and docosahexaenoic acid for utilization by the developing fetus.

Relative fatty acid composition of plasma and red blood cell (RBC) choline phosphoglycerides (CPG), and RBC ethanolamine phosphoglycerides (EPG) of pregnant (n = 40) and nonpregnant, nonlactating (n = 40), healthy Korean women was compared. The two groups were of the same ethnic origin and comparable in age and parity. Levels of arachidonic (AA) and docosahexaenoic (DHA) acids were lower (P < 0.05) and palmitic and oleic acids higher (P < 0.0001) in plasma CPG of the pregnant women. Similarly, the RBC CPG and EPG of the pregnant women had lower AA and DHA (P < 0.05) and higher palmitic and oleic acids (P < 0.01). The reduction in DHA and total n-3 fatty acids in plasma CPG of the pregnant women was paralleled by an increase in docosatetraenoic (DTA) and docosapentaenoic (DPA) acids of the n-6 series and in DPA/DTA ratio. In the RBC phospholipids (CPG and EPG) of the pregnant women, DTA and DPA acids of the n-6 series and DPA/DTA ratio did not increase with the decrease of the n-3 metabolites (eicosapentaenoic acid, DPA, and DHA) and total n-3. Since pregnancy was the main identifiable variable between the two groups, the lower levels of AA and DHA in RBC CPG and EPG of the pregnant women suggest that the mothers were mobilizing membrane AA and DHA to meet the high fetal requirement for these nutrients. It may also suggest that RBC play a role as a potential store of AA and DHA and as a vehicle for the transport of these fatty acids from maternal circulation to the placenta to be utilized by the developing fetus.

Adult↗
PubMed2000

Quantitative description of the workload associated with airway management procedures.

STUDY OBJECTIVES: To measure the workload associated with specific airway management tasks. SETTING AND INTERVENTION: Written survey instrument. PATIENTS: 166 Stanford University and 75 University of California, San Diego, anesthesia providers. MEASUREMENTS AND MAIN RESULTS: Subjects were asked to use a seven-point Likert-type scale to rate the level of perceived workload associated with different airway management tasks with respect to the physical effort, mental effort, and psychological stress they require to perform in the typical clinical setting. The 126 subjects completing questionnaires (overall 52% response rate) consisted of 43% faculty, 26% residents, 23% community practitioners, and 8% certified registered nurse-anesthetists (CRNAs). Faculty physicians generally scored lower workload measures than residents, whereas community practitioners had the highest workload scores. Overall, workload ratings were lowest for laryngeal mask airway (LMA) insertion and highest for awake fiberoptic intubation. Airway procedures performed on sleeping patients received lower workload ratings than comparable procedures performed on awake patients. Direct visualization procedures received lower workload ratings than fiberoptically guided procedures. CONCLUSIONS: These kinds of data may permit more objective consideration of the nonmonetary costs of technical anesthesia procedures. The potential clinical benefits of the use of more complex airway management techniques may be partially offset by the impact of increased workload on other clinical demands.

Adult↗
PubMed2000

A large "footprint" at the boundary of the human beta-globin locus control region hypersensitive site-2.

The 5'-boundary region of the human beta-globin locus control region hypersensitive site-2 (HS-2) was examined for protein-DNA interactions. The HS-2 is an erythroid specific DNase I hypersensitive site that extends for approximately 600 bp. Erythroid K562 cells and non-erythroid HeLa cells were damaged by bleomycin and hedamycin--these agents are able to "footprint" nucleosome cores and proteins bound to DNA. The fragments generated by DNA damage were amplified by the ligation-mediated polymerase chain reaction with primers specific for the 5'-boundary region of HS-2 and examined at base pair resolution on DNA sequencing gels. The intensity of damage in intact cells was compared with that in purified DNA. The comparison between intact cells and purified DNA revealed a protected region of 226 bp with bleomycin and 182 bp with hedamycin in K562 cells. The length of the protected region was consistent with the presence of a nucleosome core. We postulate that an erythroid-specific protein binds next to the positioned nucleosome at the boundary of HS-2 to prevent sliding of the nucleosome into the hypersensitive site--this would also account for the large size of the protected region. HeLa cells (lacking a hypersensitive site in the beta-globin cluster) did not have an area of protection in this region.

Anthraquinones↗
PubMed2000

Pregnancy reduces arachidonic and docosahexaenoic in plasma triacylglycerols of Korean women.

Plasma triacylglycerol (TG) fatty acid composition of healthy non-pregnant and non-lactating women, expectant mothers and their term neonates from Seoul, South Korea was investigated. They were ethnically homogeneous and the women had comparable age and parity. Blood samples were obtained at recruitment, third trimester and birth from the non-pregnant women, expectant mothers and neonates respectively. Percent levels of linoleic and arachidonic acids and n-6 metabolites and total n-6 were significantly lower in the pregnant women than in the non-pregnant (p < 0.0001). Similarly, there were lower levels of alpha-linolenic (p = 0.033), eicosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 (p < 0.0001) in the expectant mothers. Compared with their mothers, the neonates had higher proportions of dihomo-gamma-linolenic, arachidonic, docosatetraenoic and docosapentaenoic acids and n-6 metabolites (p < 0.0001) and lower linoleic acid (p < 0.0001). Of the n-3 series, alpha-linolenic acid was lower (p < 0.0001) and eicosapentaenoic, docosapentaenoic and docosahexaenoic acids and n-3 metabolites and total n-3 higher (p < 0.0001) in the neonates compared with their mothers. The study reveals that pregnancy is associated with a reduction in the relative levels of plasma triacylglycerol arachidonic and docosahexaenoic acids. Moreover, it indicates that the decline is a manifestation of selective transfer of these fatty acids to the developing fetus.

Adult↗
PubMed2000

The progression of mediastinal lymphangioma in utero.

We describe a case of mediastinal lymphangioma that suddenly progressed in utero. The initial sonographic impression was one of pericardial effusion while the follow-up examination revealed a mediastinal cystic mass. At 35 weeks of gestation preterm labor occurred. An ultrasound examination performed at this time demonstrated the mediastinal cyst with internal hemorrhage and fetal hydrops. The cystic mass was resected 5 days after birth. The diagnosis of lymphangioma was made from histological examination. The infant was followed up for 18 months and remained well. We recommend frequent prenatal sonographic follow-up when a localized fluid collection is, shown in the mediastinum.

Adult↗
PubMed2000

Renal tubulointerstitial injury from ureteral obstruction in the neonatal rat is attenuated by IGF-1.

BACKGROUND: The administration of insulin-like growth factor-1 (IGF-1) has been shown to ameliorate the renal injury resulting from ischemic acute renal failure. As there are a number of similarities between acute renal failure and obstructive nephropathy, we examined the effects of IGF-1 on the renal cellular response to unilateral ureteral obstruction (UUO) in the neonatal rat. METHODS: Forty-five rats were subjected to UUO or sham operation within the first 48 hours of life and received IGF-1 (2 mg/kg/day) or saline for the following three or seven days, after which kidneys were removed for study by morphometry and immunohistochemistry. To determine the effects of UUO on endogenous expression of IGF-1 and its receptor, six additional rats were subjected to UUO or sham operation, and mRNA was measured by solution hybridization. RESULTS: There was no effect of seven days of UUO on the renal expression of endogenous IGF-1 or its receptor. Moreover, seven days of exogenous IGF-1 did not improve the suppression of nephrogenesis, the delay in glomerular maturation, or the reduction in tubular proliferation induced by ipsilateral UUO. However, in the obstructed kidney, IGF-1 reduced tubular expression of vimentin, apoptosis, and tubular atrophy by 38 to 50% (P < 0.05). In addition, IGF-1 also decreased renal interstitial collagen deposition in the obstructed kidney by 44% (P < 0.05). Following three days of UUO, the administration of IGF-1 also reduced tubular apoptosis (P < 0.05), but did not alter tubular proliferation. CONCLUSIONS: IGF-1 has a profound salutary effect on the tubular and interstitial response to UUO in early development, without affecting glomerular injury or development. These results suggest that IGF-1 may have therapeutic potential in the management of congenital obstructive nephropathy.

Animals↗
PubMed2000

Scintigraphic findings in peroneal tendonitis: a case report.

A case report of radionuclide bone scan findings in a patient with peroneus brevis tendonitis is presented. Peroneal tendonopathy is a common cause of lateral ankle pain. Although magnetic resonance imaging (MRI) findings have been described in the literature, we know of no other detailed report of three-phase bone scan findings, which we believe can provide an alternate means to diagnose this condition. The positive findings consist of a curvilinear band of increased activity that corresponded to the anatomic position of the peroneus brevis tendon and was detected only on the first two phases of the study.

Adult↗
PubMed2000

Brain injury and cerebrovascular fibrin deposition correlate with reduced antithrombotic brain capillary functions in a hypertensive stroke model.

Hemostasis factors may influence the pathophysiology of stroke. The role of brain hemostasis in ischemic hypertensive brain injury is not known. We studied ischemic injury in spontaneously hypertensive rats in relation to cerebrovascular fibrin deposition and activity of different hemostasis factors in brain microcirculation. In spontaneously hypertensive rats subjected to transient middle cerebral artery occlusion versus normotensive Wistar-Kyoto (W-K) rats, infarct and edema volumes were increased by 6.1-fold (P < 0.001) and 5.8-fold (P < 0.001), respectively, the cerebral blood flow (CBF) reduced during middle cerebral artery occlusion (MCAO) by 55% (P < 0.01), motor neurologic score increased by 6.9-fold (P < 0.01), and cerebrovascular fibrin deposition increased by 6.8-fold (P < 0.01). Under basal conditions, brain capillary protein C activation and tissue plasminogen activator activity were reduced in spontaneously hypertensive rats compared with Wistar-Kyoto rats by 11.8-fold (P < 0.001) and 5.1-fold (P < 0.001), respectively, and the plasminogen activator inhibitor-1 antigen and tissue factor activity were increased by 154-fold (P < 0.00001) and 74% (P < 0.01), respectively. We suggest that hypertension reduces antithrombotic mechanisms in brain microcirculation, which may enhance cerebrovascular fibrin deposition and microvascular obstructions during transient focal cerebral ischemia, which results in greater neuronal injury.

Animals↗
PubMed2000

Threshold of induced transparency in the relativistic interaction of an electromagnetic wave with overdense plasmas

An exact analytical investigation of the stationary solutions describing the interaction between high-intensity laser radiation and an overdense plasma is presented. Both the relativistic and striction nonlinearities are taken into account, and their joint action gives rise to a solitary solution. This solution clearly shows that there exists an inherent limit of the induced transparency on the density of the overdense plasma in order to obtain a stationary physical solution. Furthermore, it is found that the striction nonlinearity tends to create a strong peaking of the plasma electron density, which suppresses the laser penetration and significantly enhances the threshold intensity for induced transparency.

Journal Article↗
PubMed2000

Nckbeta adapter regulates actin polymerization in NIH 3T3 fibroblasts in response to platelet-derived growth factor bb.

The SH3-SH3-SH3-SH2 adapter Nck represents a two-gene family that includes Nckalpha (Nck) and Nckbeta (Grb4/Nck2), and it links receptor tyrosine kinases to intracellular signaling networks. The function of these mammalian Nck genes has not been established. We report here a specific role for Nckbeta in platelet-derived growth factor (PDGF)-induced actin polymerization in NIH 3T3 cells. Overexpression of Nckbeta but not Nckalpha blocks PDGF-stimulated membrane ruffling and formation of lamellipoda. Mutation in either the SH2 or the middle SH3 domain of Nckbeta abolishes its interfering effect. Nckbeta binds at Tyr-1009 in human PDGF receptor beta (PDGFR-beta) which is different from Nckalpha's binding site, Tyr-751, and does not compete with phosphatidylinositol-3 kinase for binding to PDGFR. Microinjection of an anti-Nckbeta but not an anti-Nckalpha antibody inhibits PDGF-stimulated actin polymerization. Constitutively membrane-bound Nckbeta but not Nckalpha blocks Rac1-L62-induced membrane ruffling and formation of lamellipodia, suggesting that Nckbeta acts in parallel to or downstream of Rac1. This is the first report of Nckbeta's role in receptor tyrosine kinase signaling to the actin cytoskeleton.

3T3 Cells↗
PubMed2000

Expression of cyclooxygenase-1 and -2 in rheumatoid arthritis synovium.

The aim of this study was to investigate the expression and localization of cyclooxygenase-1 and -2 (COX-1 and COX-2) in synovial tissues from patients with rheumatoid arthritis (RA). Synovial tissues from 9 patients with RA and 5 patients with osteoarthritis (OA) were examined for COX-1 and COX-2 expressions by immunohistochemical staining using 2 polydonal COX-1 and COX-2 antibodies. In RA synovia, synovial lining cells showed intense immunostaining for COX-1, whereas slight to moderate staining was observed in inflammatory cells, stromal fibroblast-like cells and vascular endothelial cells. There was no significant difference in COX-1 expression between RA and OA synovia. The localization of COX-2 expression dearly differed from that of COX-1 expression, being most intense in inflammatory cells. However, there was no difference in COX-1 and COX-2 expressions between RA and OA synovial tissues. Our observations support that inflammatory mechanisms modulated by COX-1 and COX-2 in chronic RA synovium might be similar to those in chronic OA synovium.

Adult↗
PubMed1999

Calpain inhibitors protect auditory sensory cells from hypoxia and neurotrophin-withdrawal induced apoptosis.

Inhibitors of calpain have been shown to protect nerve growth factor (NGF)-deprived ciliary ganglion neurons and hypoxic cortical neurons. Calpains have been identified in the cochlea and are active during ischemic injury. Since apoptosis can be initiated by loss of neurotrophic support, hypoxia, and ototoxins (e.g., cisplatin, CDDP), the role of calpain inhibitors under these conditions was examined in auditory hair cells and neurons. Dissociated spiral ganglion neuron (SGN) cell cultures and organ of Corti explants from P3 rats were used to test the efficacy of calpain inhibitors as otoprotective molecules. Our results indicate that calpain inhibitor I, calpain inhibitor II, and leupeptin all provided significant protection of SGNs against neurotrophin-withdrawal and hypoxia-induced apoptosis. The increase in neuronal survival ranged from 2.16 to 2.31 times greater than in untreated neurotrophin-withdrawn SGN cell cultures. BOC-Asp(Ome)-Fluoromethyl Ketone (B-D-FMK), a general caspase inhibitor, increased neuronal survival 2.16 times more. Neuronal survival rates were from 1.88 to 2.27 times greater than in untreated, hypoxic neurons and hair cell survival rates were from 1.98 to 2.03 times greater than untreated, hypoxic organ of Corti explants. However, protection of auditory hair cells and neurons from CDDP-induced damage (10 and 6 micrograms/ml, respectively) was limited with any of these calpain inhibitors. Apoptotic pathways initiated by neurotrophin-deprivation and ototoxic stress (e.g., CDDP) have been shown to be different. Our results agree with this finding, with neurotrophin-withdrawal and hypoxia, but not CDDP damage-induced apoptosis being calpain-dependent.

Animals↗
PubMed1999

Inhibition of initiation of simian virus 40 DNA replication in vitro by the ursodeoxycholic acid and its derivatives.

In this study, the effects of the ursodeoxycholic acid (UDCA), and its derivatives, on DNA replication were examined using simian virus (SV40) DNA replication in vitro. We found that UDCA and its derivatives inhibited SV40 DNA replication, and predominantly inhibited the initiation stage of DNA replication. UDCA and its derivatives inhibited the DNA cleavage by topoisomerase I (topo I). Among them, HS-1183 significantly reduced the activity of topo I. UDCA, at 100 microM, significantly reduced polymerase alpha-primase (pol alpha-primase) activity, but HS-1030 and HS-1183 showed a weak inhibitory effect. The ssDNA binding activity of replication protein A (RPA) was little affected by UDCA and HS-1030, but was weakly inhibited by HS-1183. Based on their properties, we suggest that UDCA and its derivatives might inhibit some molecules that is required to establish replication forks during the initiation reaction and their cytotoxicity might be related to the inhibitory effect they have on this fundamental cellular process.

Antineoplastic Agents↗
PubMed1999

Protein-DNA footprinting of the human epsilon-globin promoter in human intact cells using nitrogen mustard analogues and other DNA-damaging agents.

Nitrogen mustard analogues, bleomycin and dimethyl sulphate (DMS) have been used as probes of protein-DNA interactions in intact human cells. The sites of damage have been determined at base pair resolution in the single copy epsilon-globin gene promoter in erythroid K562 cells, non-erythroid HeLa cells and purified DNA. Exponential amplification of gene-specific damage fragments was achieved using the ligation-mediated polymerase chain reaction (LMPCR) technique and analysed on DNA sequencing gels. A comparison of the relative damage band intensities between purified DNA and intact cells revealed several significant differences - both protection (footprint) and enhancement. These differences occurred at putative transcription factor binding sites and hence are thought to be due to protein-DNA interactions. A major feature of the band intensity ratio plots was the footprint observed at the CCAAT box binding motif as revealed by nitrogen mustard analogues. Enhanced band intensity (hypersensitivity) was displayed at the 5'- and 3'-ends of the CCAAT box in K562 cells - this feature was absent in HeLa cells and in vitro reconstitutions. A footprint was found at the GATA-1 motif in K562 cells that was also absent in non-expressing HeLa cells. Footprints were also evident at the TATA box, CACC box and the epsilonF1 DNA binding motif in K562 cells.

Bleomycin↗
PubMed1999

Pharmacodynamics of insulin in polyethylene glycol-coated liposomes.

To reduce the injection frequency and toxicity of intravenously administered protein drugs, it is necessary to develop safe and sustained injectable delivery systems. In this study, to evaluate liposomes as safe and sustained injectable delivery systems of proteins, we chose insulin as a model protein drug and tested its incorporation efficiency and pharmacodynamics in various liposomes with and without polyethylene glycol (PEG)-derivatized phospholipid. The liposomes coated with PEG showed 3-fold higher efficiency of insulin incorporation than did the liposomes without PEG. Moreover, among the liposomes coated with PEG, dipalmitoylphosphocholine (DPPC) liposomes showed higher incorporation efficiency than did dimyristoylphosphocholine (DMPC) liposomes. For pharmacodynamic study, insulin (2 IU/kg) was administered in various formulations, such as insulin alone in phosphate-buffered saline and insulin in the DPPC liposomes with and without PEG, to streptozotocin-treated diabetic rats. The pharmacodynamics of insulin alone, however, could not be measured due to the immediate death of rats caused by hypoglycemic shock. In contrast, all the rats treated with liposomal insulin survived, probably by the sustained release of insulin from liposomes. Pharmacodynamics of liposomal insulin showed that PEG-coated liposomes induced the lowest level of blood glucose-the nadir-1 h later than did the liposomes without PEG. These results indicate that PEG-coated liposomes could be developed as a relatively safe and sustained injectable delivery system for insulin with improved incorporation efficiency. Moreover, it is suggested that the liposomes coated with PEG might have a potential as safe injectable delivery systems for other protein and peptide drugs.

Animals↗
PubMed1999

Human endogenous retrovirus with a high genomic sequence homology with IDDMK(1,2)22 is not specific for Type I (insulin-dependent) diabetic patients but ubiquitous.

AIMS/HYPOTHESIS: It has been reported recently that a novel human endogenous retroviral gene, insulin-dependent diabetes mellitus (IDDM)K(1,2)22, was expressed in the plasma of Type I diabetic patients but not in that of nondiabetic control subjects. This investigation was initiated to determine the specificity of the selective expression of IDDMK(1,2)22 in diabetic patients. METHODS: We isolated the total RNA from the plasma and lymphocytes of 13 new onset Type I diabetic patients and 10 normal control subjects and amplified it by reverse transcriptase polymerase chain reaction. We then determined the presence of IDDMK(1,2)22 with a specific primer set, U3/R-poly(A), used in a recent report and the 5 'SAg/3 'SAg primer set recognizing the putative superantigen encoding the region of the IDDMK(1,2)22 envelope (env) gene. In addition, we carried out nested PCR of the U3/R-poly(A) polymerase chain reaction product using U3N/R primers. RESULTS: We found no difference in the presence of the polymerase chain reaction products between diabetic patients and all nondiabetic subjects tested. Sequencing of the U3/R-poly(A) polymerase chain reaction products showed that the exact sequence of IDDMK(1,2)22 was not present in any of the samples tested, neither in the plasma of diabetic patients nor in that of nondiabetic control subjects. Endogenous retroviral sequences with 90-93% sequence homology to IDDMK(1,2)22 were, however, equally present in both the diabetic and nondiabetic subjects. CONCLUSION/INTERPRETATION: We conclude that a human endogenous retroviral gene with high sequence homology with IDDMK(1,2)22 is not specific for diabetic patients but, rather, is ubiquitous.

Base Sequence↗
PubMed1999

The hemodynamics of steal syndrome and its treatment.

A 61-year-old man developed steal syndrome after creation of a transposed basilic vein arteriovenous fistula (AVF) resulting in rest pain and ischemic ulcers in the fingertips. Our initial surgically created stenosis reduced the diameter by 32% and the area by 56%, and increased the radial artery pressure from 52 to 78 mmHg, with relief of symptoms. Within 3 weeks his symptoms reappeared. Repeat measurements did not explain his return of symptoms. A second area of stenosis was created in the AVF, with a diameter reduction of 75%, and an area reduction of 94%. His symptoms resolved, and his ulcers healed. The hemodynamics of the AVF and the steal syndrome were evaluated by duplex imaging and Doppler pressure assessment. A greater stenosis increased the radial artery pressure from 78 to 140 mmHg while maintaining flow through the AVF. Rather than increasing the degree of stenosis at the first site, we created a second area of stenosis. Hemodynamically, this would be additive to the first without the risk of creating a high-grade stenosis that could thrombose the AVF. Increasing the resistance in the AVF will decrease flow in the AVF and, ultimately, increase flow to the hand.

Aged↗