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Biomedical subjects

K J Kim

Publications and source records attributed to K J Kim.

At least 127 records · Page 7Linked to original sources
PubMed1997

Renovascular hypertension in children with moyamoya disease.

OBJECTIVES: To examine the incidence, clinical and radiologic findings, and response to treatment of renovascular hypertension (RVHT) in moyamoya disease (MMD). METHODS: A retrospective analysis of medical records in six RVHT cases (8.3%) among 72 MMD patients observed from November 1987 to December 1995. RESULTS: The age at onset of MMD ranged from 9 months to 7 years 1 month (mean, 3.3 years). The most common initial manifestation of MMD was transient ischemic attack. Hypertension was detected between 4 years 4 months and 12 years 3 months (mean, 7.87 years). Unstimulated plasma renin activity was elevated in all six cases. Renal ultrasonography and captopril technetium 99m-labeled dimercaptosuccinic acid scan showed abnormal findings in four of five and in three of four available studies, respectively. However, both imaging studies showed abnormal findings only in the most severely affected kidneys even with bilateral renal artery stenosis. Renal arteriography revealed bilateral lesions in three of the patients and unilateral lesions in the others. Renal angioplasty was performed in four cases but was successful in only one and partially successful in another. A renal artery specimen obtained during renal autotransplantation showed intimal fibroplasia. At the last follow-up, one patient had normal blood pressure without the use of antihypertensive agents, but the other five patients needed this medication to control blood pressure. CONCLUSION: Because RVHT may be more commonly associated with MMD than has hitherto been appreciated, it is recommended that blood pressure be carefully followed and that diagnostic procedures for RVHT be carried out in hypertensive patients with MMD.

Adolescent↗
PubMed1997

Large amounts of polyethylene debris in the interface tissue surrounding bipolar endoprostheses. Comparison to total hip prostheses.

A histologic and biochemical comparison of interface membranes around femoral components of bipolar endoprostheses (n = 17) and total hip prostheses (n = 17) inserted without cement was conducted. The patients' profiles were similar in both groups with respect to age, sex, primary diagnosis, weight, and the interval between primary and revision arthroplasty. Macroscopically, marked circumferential abrasion of the polyethylene insert in the retrieved bipolar cups was noted. Histologic analysis revealed significantly larger amounts of polyethylene debris in the bipolar group. The membranes from the bipolar group also produced significantly greater amounts of prostaglandin E2 (P < .05). The inflammatory membranes associated with large amounts of polyethylene debris may have contributed to aseptic loosening and osteolysis in patients with a bipolar hip prosthesis.

Collagenases↗
PubMed1997

Size-dependent dextran transport across rat alveolar epithelial cell monolayers.

The transport of dextrans (approximately 4 to approximately 150 kDa) across an in vitro model of the alveolar epithelial barrier was studied to determine the effects of molecular size on pulmonary absorption of macromolecular drugs. Fluorescein isothiocyanate (FITC)-labeled dextrans (FDs) with average molecular weights (all in kDa) of 3.86 (FD4), 9 (FD10), 19.8 (FD20), 40.5 (FD40), 71.6 (FD70), and 156.9 (FD150) were utilized as model macromolecular drugs. Unidirectional fluxes of FDs at 37 and 4 degrees C were measured from the appearance rates of FD in the receiver fluid of open-circuited monolayers (>2000 omega-cm2) of rat alveolar epithelial cells. Apparent permeability coefficients (P(app)) were estimated from the observed flux and the corresponding concentration gradient of FD. Results showed that FD fluxes were the same in both apical-to-basolateral (AB) and opposite (BA) directions at each molecular weight studied. The P(app) was not significantly different at 0.5 and 1.0 mg/mL FD40 donor concentrations. The FD P(app) (x 10(-8)cm/s) decreased gradually from 1.35 for FD4 to 0.32 for FD40, indicating an apparent inverse relationship between P(app) and molecular weight of FD. By contrast, P(app) was about the same at 0.13 for both FD70 and FD150. When experimental temperature was lowered to 4 degrees C, P(app) decreased by approximately 40% for FDs of 4 through 40 kDa, whereas the decrease in P(app) was by approximately 80% for larger FDs of both 70 and 150 kDa. Moreover, these FDs were found to be relatively intact (approximately 90%) in either receiver fluid after 5-h flux experiments without detectable levels of metabolites in the respective donor fluid, suggesting that alveolar epithelial cells allow translocation of FDs intact across the barrier. Equivalent pore analysis, assuming restricted diffusion of FDs of 4-40 kDa via cylindrical, water-filled pores across the cell monolayer revealed a population of large equivalent pores with approximately 5.6 nm radius. These data suggest that smaller macromolecules (radius <5 nm) traverse the alveolar epithelial barrier via paracellular pathways, and that larger (i.e., radius > or = 6 nm) macromolecules likely cross the barrier via other pathways (e.g., pinocytosis).

Absorption↗
PubMed1997

Polar solute transport across the pigmented rabbit conjunctiva: size dependence and the influence of 8-bromo cyclic adenosine monophosphate.

PURPOSE: To characterize the conjunctival permeability to polar solutes ranging from 182 to 167,000 daltons in molecular weight (m.w.). METHODS: Solute transport across the excised pigmented rabbit conjunctiva with a baseline transepithelial electrical resistance (TEER) of 1,285 +/- 46 ohm.cm2 was evaluated in the modified Ussing chamber under open-circuit conditions. The model solutes were mannitol (m.w. 182), 6-carboxyfluorescein (m.w. 376), and fluorescein isothiocyanate-labeled dextrans (FD4, m.w. 4,400-FD150, m.w. 167,000). RESULTS: For a given solute, the apparent permeability coefficient (Papp) was independent of solute concentration and direction of transport. As expected, the Papp decreased with solute size, from 27.7 x 10(-8) cm/sec for mannitol to 0.31 x 10(-8) cm/sec for FD150. When the experimental temperature was lowered from 37 degrees C to 4 degrees C. Papp decreased by approximately 50% for FD4 through FD40 and by > 80% for both FD70 and FD150. Equivalent pore analysis, assuming restricted solute diffusion via cylindrical, water-filled pores across the isolated tissue, revealed a radius of 5.5 nm at a pore density of 1.9 x 10(8) pores per cm2. The addition of 1 mM 8-bromo cyclic adenosine monophosphate (8-BrcAMP), known to stimulate Cl- secretion and decrease TEER, to the mucosal side of the conjunctiva increased the transport of mannitol, FD4, and FD40 by 28%, while not affecting FD150 transport. CONCLUSIONS: Our findings suggest that polar solutes up to FD40 traverse the conjunctival epithelial barrier primarily by restricted diffusion through equivalent pores of 5.5 nm radius and that solute movement is affected by reduction of TEER. On the other hand, polar solutes of the FD70 or larger may cross the barrier primarily via non-diffusional pathways such as non-specific endocytosis.

Animals↗
PubMed1997

Kinetic evidence for Na(+)-glucose co-transport in the pigmented rabbit conjunctiva.

PURPOSE: To obtain kinetic evidence for the existence of a Na(+)-coupled glucose co-transport process on the mucosal (tear) side of the pigmented rabbit conjunctiva. METHODS: The excised pigmented rabbit conjunctiva was mounted in the modified Ussing chamber for measurement of 22Na and 3H-3-O-methyl-D-glucose (3-O-MG) fluxes. RESULTS: In the presence of 5 mM glucose, the conjunctival tissue showed net Na+ absorption in the mucosal-to-serosal direction at an approximate rate of 0.15 microEq/cm2/h. This net Na+ absorption was abolished by serosally added 0.5 mM ouabain, but not affected by mucosally added 0.1 mM or 1 mM amiloride. There was a 40-60% reduction in net Na+ absorption under the glucose-free condition or in the mucosal presence of 0.5 mM phlorizin. Moreover, serosally added ouabain and mucosally added phlorizin (both at 0.5 mM) significantly decreased the 3-O-MG permeability coefficient in the mucosal-to-serosal direction by about 70%, whereas mucosally instilled 0.1-1.0 mM amiloride was without any effect. Three-O-MG absorption in the mucosal-to-serosal direction appeared to be coupled with Na+ transport with a 1:1 stoichiometry. In addition, this process exhibited temperature dependency, saturability, and directionality. CONCLUSION: Our findings are consistent with Na(+)-glucose cotransport as being one of the mechanisms for mucosal Na+ entry into the epithelial cells of the pigmented rabbit conjunctiva.

3-O-Methylglucose↗
PubMed1997

Identification of the binding site in intercellular adhesion molecule 1 for its receptor, leukocyte function-associated antigen 1.

Intercellular adhesion molecule 1 (ICAM-1, CD54) is a member of the Ig superfamily and is a counterreceptor for the beta 2 integrins: lymphocyte function-associated antigen 1 (LFA-1, CD11a/CD18), complement receptor 1 (MAC-1, CD11b/CD18), and p150,95 (CD11c/CD18). Binding of ICAM-1 to these receptors mediates leukocyte-adhesive functions in immune and inflammatory responses. In this report, we describe a cell-free assay using purified recombinant extracellular domains of LFA-1 and a dimeric immunoadhesin of ICAM-1. The binding of recombinant secreted LFA-1 to ICAM-1 is divalent cation dependent (Mg2+ and Mn2+ promote binding) and sensitive to inhibition by antibodies that block LFA-1-mediated cell adhesion, indicating that its conformation mimics that of LFA-1 on activated lymphocytes. We describe six novel anti-ICAM-1 monoclonal antibodies, two of which are function blocking. Thirty-five point mutants of the ICAM-1 immunoadhesin were generated and residues important for binding of monoclonal antibodies and purified LFA-1 were identified. Nineteen of these mutants bind recombinant LFA-1 equivalently to wild type. Sixteen mutants show a 66-2500-fold decrease in LFA-1 binding yet, with few exceptions, retain binding to the monoclonal antibodies. These mutants, along with modeling studies, define the LFA-1 binding site on ICAM-1 as residues E34, K39, M64, Y66, N68, and Q73, that are predicted to lie on the CDFG beta-sheet of the Ig fold. The mutant G32A also abrogates binding to LFA-1 while retaining binding to all of the antibodies, possibly indicating a direct interaction of this residue with LFA-1. These data have allowed the generation of a highly refined model of the LFA-1 binding site of ICAM-1.

Animals↗
PubMed1997

Effects of Mycobacterium tuberculosis on the bioelectric properties of the alveolar epithelium.

To investigate the hypothesis that Mycobacterium tuberculosis penetrates the alveolar epithelium by downregulating its barrier properties, we evaluated the interactions between M. tuberculosis and rat alveolar epithelial cell monolayers that are believed to share electrophysiologic properties of the human alveolar epithelium. Nonproteinaceous components of M. tuberculosis caused marked declines in electrical resistance and equivalent short-circuit current of the alveolar epithelial cell monolayers, indicating a reduction in the capacity to maintain tight intercellular junctions and to actively reabsorb sodium. M. tuberculosis elicited production of TNF-alpha mRNA and protein by alveolar epithelial cells, and the effects of recombinant TNF-alpha on the bioelectric properties of the alveolar epithelial paralleled those of M. tuberculosis. Furthermore, the effects of M. tuberculosis on alveolar epithelial resistance were abrogated by neutralizing anti-TNF-alpha antibodies. These results indicate that M. tuberculosis elicits production of TNF-alpha, which in turn reduces the bioelectric barrier properties of the alveolar epithelium. These findings provide insight into potential mechanisms by which M. tuberculosis establishes infection and disease in the lung.

Animals↗
PubMed1997

Effects of 'crack' cocaine on pulmonary alveolar permeability.

BACKGROUND: Lung clearance of 99mTc-labeled diethylenetriamine pentaacetate (DTPA) is a sensitive test of altered alveolar epithelial permeability that has been found to be increased in smokers of tobacco, as well as a small number of healthy smokers of crack cocaine, suggesting the possibility of subclinical crack-related lung injury. STUDY OBJECTIVE: To evaluate further whether habitual smoking of cocaine alone alters alveolar permeability, whether crack smoking adds to or potentiates the effects of tobacco and/or marijuana, and whether experimental cocaine smoking acutely alters DTPA lung clearance. DESIGN: Observational cohort study (habitual cocaine smoking) and single-blind crossover study (experimental cocaine administration). SUBJECTS: Fourteen habitual smokers of cocaine alone (CS), 19 smokers of cocaine and tobacco (CTS), 3 smokers of cocaine and marijuana, 12 smokers of cocaine, tobacco, and marijuana (CMTS), and 5 smokers of marijuana plus tobacco (MTS). Results obtained in the crack-smoking subjects were compared with data previously obtained in 10 nonsmokers (NS), 9 smokers of tobacco alone (TS), 10 smokers of marijuana alone (MS), and 4 additional MTS. METHODS: Subjects underwent measurements of DTPA radioaerosol lung clearance after refraining from marijuana and/or cocaine for > 12 h and from tobacco for >2 h. Ten of the 48 crack users were tested on two days 1 to 2 weeks apart within 2 h of experimental smoking of three physiologically active or inactive doses (total 98.8+/-15.5 or 8.5+/-2.5 mg, respectively) of cocaine base. Lung clearance half-times (T1/2) were computed from time-activity curves for each lung. RESULTS: T1/2 values for each lung in CS and MS were comparable to those of NS, while TS, MTS, CTS, and CMTS had significantly shorter clearance rates than NS (p<0.01; three-way analysis of variance). No additive or interactive effects on T1/2 were noted among tobacco, cocaine, and/or marijuana. No acute effect of experimental cocaine smoking on T1/2 was noted. CONCLUSION: Whereas regular smoking of tobacco alone or with other substances increases alveolar epithelial permeability, habitual smoking of cocaine and/or marijuana has no measurable effect on alveolar permeability in the absence of tobacco nor any additive effect to that of tobacco alone.

Adult↗
PubMed1997

Molecular analysis of hypoxanthine guanine phosphoribosyltransferase (HPRT) gene in five Korean families with Lesch-Nyhan syndrome.

Lesch-Nyhan syndrome is caused by the complete deficiency of hypoxanthine guanine phosphoribosyl-transferase (HPRT). By the analysis of genomic DNA and mRNA using the polymerase chain reaction (PCR) technique coupled with direct sequencing, five independent mutations in HPRT genes have been identified in Korean Lesch-Nyhan families. Two novel mutations and three previously reported mutations have been found in five independent families. Heterozygous carriers were detected in all the families, and prenatal diagnosis was carried out in two families.

Exons↗
PubMed1997

The factors related to recurrence after transcatheter arterial embolization for the treatment of hemoptysis.

OBJECTIVES: Massive hemoptysis is a major clinical problem associated with high morbidity and mortality. Transcatheter arterial embolization is widely used for the treatment of massive hemoptysis, but it was reported that the recurrence rate after embolization is 12-54% in the previous studies. We evaluated the therapeutic effect of transcatheter arterial embolization for the treatment of massive hemoptysis and the factors related to recurrence. METHODS: We reviewed 51 patients (M:F = 36:15) of transcatheter arterial embolization for the treatment of massive hemoptysis from Jan 1988 to Dec 1994, retrospectively. RESULTS: After arterial embolization, immediate successful control (< 1 wk) of massive hempotysis was achieved in 48 of 51 patients (94.1%) and recurrence of hemoptysis was observed in 17 of 51 patients (33.3%) during the follow-up period. The patients with non-bronchial artery hemoptysis and multiple artery bleeding had increased tendency of recurrence (77.7%). On the previous history of hemoptysis, the patients with massive hemoptysis (> 400 ml/24hr) or frequent history of hemoptysis had increased tendency of recurrence (87.5%, 72.7%). CONCLUSION: Transcatheter arterial embolization is a useful and safe procedure for immediate control in massive hemoptysis. However, the patients with this procedure had a potentiality for recurrence. We suggest that close follow-up and caution will be needed in the patients with multiple artery bleeding or with large amounts of hemoptysis or with previous episodes more than 3 times.

Adult↗
PubMed1997

Blunt traumatic rupture of the diaphragm: sonographic diagnosis.

Ultrasonographic features of seven patients with diaphragmatic rupture due to blunt trauma were analyzed. The ruptures occurred at the left hemidiaphragm in four patients and at the right in three. Direct ultrasonographic findings were as follows: disrupted diaphragm in four patients; nonvisualized diaphragm in three patients; floating diaphragm in two patients; and herniation of the liver or bowel loops through the diaphragmatic defect in three patients. Indirect sonographic findings included pleural effusion or subphrenic fluid collection in five patients and splenic laceration in one. Although the number of patients was limited, ultrasonography was very useful for the diagnosis of diaphragmatic rupture.

Adult↗
PubMed1997

MR of childhood metachromatic leukodystrophy.

PURPOSE: To investigate the MR findings of childhood metachromatic leukodystrophy (MLD). METHODS: Nine MR imaging studies in seven children (five girls and two boys, 10 to 32 months old) with MLD were evaluated retrospectively for the extent and progression of white matter abnormalities and the presence of contrast enhancement. RESULTS: All seven cases showed symmetric, confluent high signal intensity on T2-weighted images in the periventricular white matter and centrum semiovale. A posterior predominance of white matter abnormalities was noted in all cases. Although initially spared from demyelination in all cases, in one case, the subcortical U fibers were later involved in demyelination of follow-up MR studies. Other sites of involvement were the genu (n = 5) and splenium (n = 6) of the corpus callosum, the posterior limbs of the internal capsule (n = 5), the descending pyramidal tracts (n = 4), the claustrum (n = 4), and the cerebral white matter (n = 2); diffuse brain atrophy was seen in two cases. No enhancement of the lesion was seen on any of the five postcontrast examinations. A "tigroid" pattern, previously described in cases of Pelizaeus-Merzbacher disease, was noted in the centrum semiovale in six cases. CONCLUSION: In late-infantile MLD, demyelination is more prominent in the occipital region. In addition to demyelination of the periventricular white matter, common manifestations include a "tigroid" pattern and involvement of the corpus callosum, the internal capsule, and the corticospinal tract.

Brain↗
PubMed1996

Release of leukemia inhibitory factor in primate sepsis. Analysis of the role of TNF-alpha.

Leukemia inhibitory factor (LIF), a pleiotropic cytokine with many biologic effects overlapping with those of IL-6, has been implicated in the pathogenesis of sepsis. We here analyzed the kinetics of LIF in 13 baboons challenged with a lethal (n=6) or sublethal (n=7) dose of Escherichia coli. In addition, to assess the role of TNF-alpha in the induction of LIF in vivo, seven baboons were studied that had either received a bolus injection of recombinant human TNF-alpha (100 micrograms/kg, n=3), or to whom 15 mg/kg of an anti-TNF mAB before lethal E. coli challenge was administered (n=4). LIF levels increased 2 h after E coli challenge, and reached maximum values at 4 and 8 h after a sublethal (4.4 +/- 1.6 ng/ml) or lethal (40.9 +/- 3.8 ng/ml) dose, respectively. TNF-alpha injection induced a modest rise in LIF concentrations, peaking after 6 h (228 +/- 46 pg/ml). Circulating LIF correlated with plasma levels of IL-6, both after E. coli challenge (Spearman Rank coefficient of correlation (r) = 0.849, p<0.001), as well as upon TNF-alpha injection (r=0.863, p<0.001). Moreover, the E. coli-induced release of either cytokine was reduced 6- to 10-fold after pretreatment with anti-TNF mAb, except in one nonsurviving animal, which exhibited a progressive increase of LIF and IL-6 levels despite the absence of TNF immunoreactivity. These results show that TNF-alpha is an intermediate factor in concerted release of LIF and IL-6 in vivo, and indicate that the enhanced elaboration of these cytokines may predict disease outcome in severe sepsis.

Animals↗
PubMed1996

Vascular endothelial growth factor promotes tumor dissemination by a mechanism distinct from its effect on primary tumor growth.

Tumor growth is dependent on new blood vessel formation. Inhibition of vascular endothelial growth factor (VEGF), an endothelial cell mitogen and angiogenic factor secreted by a variety of tumors and tumor cell lines, is sufficient to inhibit primary tumor growth. In the present study, we examined the effect of inhibiting VEGF on tumor cell micrometastasis. A transfectant of A431 (a human epidermoid carcinoma cell line) expressing chloramphenicol acetyltransferase (CAT) was injected s.c. into severe combined immunodeficiency (scid) mice, which were then sacrificed after 6 weeks. The presence of A431 metastases at distant sites was demonstrated by detection of CAT activity in whole-organ lysates. Treatment of animals with VEGF-neutralizing antibodies not only inhibited primary tumor growth but also suppressed metastases, as determined by CAT activity in organ lysates. In experiments to determine the mechanism by which anti-VEGF antibody inhibited metastasis, control animals were sacrificed when their tumors had reached the same size as tumors in VEGF antibody-treated animals. Metastases were uniformly present in these control animals. These findings show that inhibition of VEGF alone is sufficient to prevent tumor growth and dissemination in vivo. The inhibitory effect on metastases appears to be distinct from that on primary tumor growth.

Animals↗
PubMed1996

Activation of osteoclast-mediated bone resorption by the supernatant from a rabbit synovial cell line in response to polyethylene particles.

It is unknown whether the soluble factors produced from cells activated by wear particles in the fibrous tissue around failed joint prostheses really activate osteoclastic bone resorption. In this study, the activation of osteoclast-mediated bone resorption by the products from a rabbit synovial cell line (HIG-82) stimulated by various particles was investigated using rabbit unfractionated bone cells cultured on a dentin slice. The HIG cells were challenged with the following laboratory-made particles: high-density polyethylene (PE), cobalt alloy (Co-Cr), titanium alloy (Ti6Al4V), pure titanium (Ti), and sintered hydroxyapatite (HA). The size of each particle was < 2 microns. The supernatants from HIG cells cultured with the appropriate concentration of wear particles were added to unfractionated bone cells on a dentin slice, and then resorbed areas were determined for each particle. Interestingly, resorbed areas significantly increased only when the culture medium from HIG cells with PE particles was added to unfractionated bone cells. This study demonstrates that PE particles stimulate the rabbit synovial cells to produce soluble factors that induce osteoclast-mediated bone resorption. Moreover, this experimental model is a useful method sensitively to evaluate the effects of soluble factors from the cells stimulated by particulate biomaterials from joint prostheses on osteoclastic bone resorption.

Animals↗