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Biomedical subjects

K M Kim

Publications and source records attributed to K M Kim.

At least 199 records · Page 11Linked to original sources
PubMed1989

Primary carcinoid tumor of the larynx.

A case of laryngeal carcinoid in a 54-year-old Korean female is reported and discussed. This tumor is extremely rare in the larynx and there have been just over twenty cases reported in the literature to date. The case showed an initial histologic finding of epithelial dysplasia and was finally confirmed to be a carcinoid tumor. Laryngeal carcinoids are often atypical histologically and may be misdiagnosed as undifferentiated carcinoma. An electron microscopic study revealed neurosecretory-type granules. Although the patient underwent a total laryngectomy and radical neck dissection, multiple hepatic metastasis was noted postoperatively.

Carcinoid Tumor↗
PubMed1988

Postnatal changes in plasma burst-promoting activity (BPA) levels in preterm infants.

Two-stage cell culture assays were used to determine burst-promoting activity (BPA) levels in the plasma of untransfused premature infants during the early anaemic period. The plasma BPA levels decreased during the early phase of the postnatal fall in haemoglobin and the mean plasma BPA levels at 2 and 4 weeks of age were significantly lower (24 +/- 9% and 20 +/- 14%) than those of normal adults (53 +/- 17%). After 8 weeks of age, plasma BPA levels increased markedly in correlation with the recovery of erythropoiesis. Inhibitors of erythroid colony growth were not significantly elevated in the plasma of premature infants. These results suggest that BPA may act as a regulator of erythropoiesis in preterm infants along with erythropoietin.

Adult↗
PubMed1988

IgE receptor-bearing lymphocytes in allergic and nonallergic children.

Using a monoclonal anti-human IgE receptor (Fc epsilon R) antibody, the percentage of Fc epsilon R(+) cells among peripheral blood lymphocytes in children with or without allergic disorders was determined. The percentage of Fc epsilon R(+) cells in 63 nonallergic children was 4.3 +/- 1.5%, which did not vary with age and was equal to that of adults (4.2 +/- 1.2%). Allergic younger children (0-2 yr) showed a significantly higher percentage of Fc epsilon R(+) cells (7.7 +/- 3.0%) than nonallergic younger children (0-2 yr) (4.0 +/- 1.3%, p less than 0.001). Similarly, in allergic younger children, serum IgE levels (geometric mean = 58.9 IU/ml) were also significantly higher than those of nonallergic younger children (geometric mean = 2.0 IU/ml) (p less than 0.01). A positive correlation between the percentages of Fc epsilon R(+) cells and serum IgE levels was observed (Spearman rank = 0.88, p less than 0.01] in eight allergic younger children (0-2 yr) with serum IgE levels higher than 100 IU/ml. The increase in the percentage of Fc epsilon R(+) cells in allergic younger children (0-2 yr) was not a secondary phenomenon caused by serum IgE because serum IgE levels in these children were much lower than the concentration at which IgE enhance Fc epsilon R expression on lymphocytes. In conclusion, Fc epsilon R(+) lymphocytes may play a regulatory role in IgE synthesis in allergic younger children (0-2 yr).

Adolescent↗
PubMed1988

Regulation of Fc epsilon receptor expression on a human monoblast cell line U937.

Fc epsilon receptor (Fc epsilon R) expression on several human cell lines (U937, RPMI 8866, HL 60, THP-1, and Molt 4) and its regulation were examined by immunofluorescent analysis using a monoclonal anti-human Fc epsilon R antibody, H107. Phorbol ester (PMA), recombinant gamma interferon (IFN-gamma) and H107 itself enhanced Fc epsilon R expression on a FC epsilon R positive cell line U937, whereas these reagents did not induce FC epsilon R expression on the Fc epsilon R negative cell lines, Molt 4, HL 60 and THP-1. Dexamethasone not only suppressed by 50% the spontaneous Fc epsilon R expression on U937 cells but also completely inhibited the enhancement of their Fc epsilon R expression on U937 cells induced by PMA, IFN-gamma or H107. Dexamethasone caused a little suppression of Fc epsilon R expression by RPMI 8866 cells. The results showed that Fc epsilon R expression on a human monoblast cell line U937 was up- or down-regulated by a variety of physiological or pharmacological agents. These experimental systems provide a good model for the investigation of the regulatory mechanisms of Fc epsilon R expression.

Antibodies, Monoclonal↗
PubMed1988

Low burst-promoting activity (BPA) production by cord mononuclear cells is due to functional immaturity of monocytes.

Cord blood mononuclear cells produced lower burst-promoting activity (BPA) than adult peripheral blood mononuclear cells when stimulated with phytohemagglutinin (PHA). In order to examine the cellular basis of the low production of BPA by PHA-stimulated cord blood mononuclear cells in the context of the functional immaturity of T cells or monocytes, we studied BPA production by T cells or monocytes from cord blood and adult peripheral blood. Cord T cells produced as much BPA as adult T cells. Monocytes themselves did not produce significant BPA at the concentration used in this experiment (1 x 10(5)/ml). BPA production by adult T cells was significantly enhanced by the presence of autologous monocytes. BPA production by cord T cells was also enhanced by the presence of adult monocytes but not by that of cord monocytes. Cord monocytes did not enhance BPA production by adult T cells either. These results indicate that cord monocytes are primarily responsible for the low BPA production by PHA-stimulated cord mononuclear cells.

Erythropoiesis↗
PubMed1988

Biomaterial-associated calcification: pathology, mechanisms, and strategies for prevention.

Deposition of calcium-containing apatite mineral occurs widely in association with cardiovascular and noncardiovascular medical devices and biomaterials, is the leading cause of failure of contemporary bioprosthetic heart valves, and limits the functional lifetime of experimental (and potentially clinical) mechanical blood pumps and polymeric heart valves. Calcification of bioprosthetic tissue is primarily intrinsic, related to cuspal connective tissue cells and fragments, and collagen. In contrast, the predominant site of calcific crystals on flexing polymeric surfaces in blood pumps or valve prostheses is extrinsic, associated with adherent cells, thrombus, or pseudointima. Pathologic calcification shares key features with physiologic skeletal mineralization, including crystal initiation through the mediation of cell membranes, usually in the form of extracellular vesicles. This suggests a unified hypothesis for normal and abnormal mineralization. Several approaches are being studied experimentally for the inhibition of bioprosthetic heart valve calcification. Controlled-release diphosphonate therapy, perhaps in conjunction with an anticalcification cuspal pretreatment, appears most effective. Research objectives in biomaterial-associated calcification include (1) development of animal models, (2) determination of initial crystal nucleation events and sites, (3) elucidation of the relative roles of host, implant, and mechanical determinants, and (4) development of approaches for the inhibition of mineralization.

Assisted Circulation↗
PubMed1987

Establishment of a common acute lymphoblastic leukemia cell line (LC4-1) and effects of phorbol myristate acetate (PMA) on the surface antigen expression of the cell line.

A common acute lymphoblastic leukemia (ALL) cell line, designated LC4-1, was established from peripheral blood mononuclear cells of a patient with acute non-T-cell ALL. LC4-1 cells were characteristically positive for Ia, B4, and common ALL antigens (CALLA), but negative for B2, Tac, T3, T4, T8, T11, and M1 antigens and E-rosette formation. Approximately 30% of LC4-1 cells expressed detectable amounts of B1 antigens. LC4-1 cells expressed neither Epstein-Barr-virus-associated nuclear antigen (EBNA), cytoplasmic immunoglobulins (cIg) nor surface immunoglobulins (sIg). Gene rearrangements had already occurred in LC4-1 in the D-J region of immunoglobulin heavy chain genes, but not in T-cell receptor (beta-chain) genes, suggesting that LC4-1 is a progenitor cell line of B-cell lineage earlier than pre-B-cells. The expression of cell surface antigens of LC4-1 was changed by treatment with 4-phorbol 12-myristate 13-acetate (PMA) (0.1 ng/ml) for 2 days. Before treatment with PMA, about 98% of LC4-1 cells were positive for B4, CALLA, and Ia. However, following treatment they lost CALLA expression without any change in expression of Ia and B4. There was no change in B1-positive population. The change in surface antigens on LC4-1 cells seems to be due to differentiation induced in the cells by PMA. These results support the hypothesis that CALLA is a differentiation antigen and suggest one possible differentiation pathway for pre-B-cells.

Antibodies, Monoclonal↗
PubMed1987

The significance of gastric bile reflux seen at endoscopy.

We evaluated the significance of bile seen in the stomach at the time of endoscopy. Twenty-three percent of 110 consecutive patients undergoing elective panendoscopy were found to have bile in their stomachs. Gastric biopsies were obtained from these patients. To assess the significance of bile reflux, the patients underwent a quantitative gastric bile analysis on two separate days. On day 1, gastric juice was aspirated by nasogastric suction, and bile acid concentrations were measured. On day 2, bile reflux into the stomach was quantitated by scintiscan measurement of gastric nucleotide after intravenous administration of 99mTc-DISIDA. Approximately half the patients with bile reflux showed histologic evidence of mucosal injury. However, fewer than half with histologic injury had significant bile reflux when measured by quantitative methods. There was no correlation among the gastric bile acid concentration, degree of histologic injury, or severity of endoscopic changes. We conclude that finding bile reflux at endoscopy is probably of no clinical significance.

Bile Reflux↗
PubMed1987

Laryngeal pacemaker using a temperature sensor in the canine.

With the use of a temperature sensor that would detect temperature changes during the respiratory cycle in the pharynx, electrical stimulation of the posterior cricoarytenoid muscle was achieved in dogs whose recurrent laryngeal nerves were artificially paralyzed. Due to the temperature difference between inspiratory and expiratory air flow, a trigger pulse was generated at the beginning of inspiration. The stimulation pulse following the trigger pulse stimulated the electrodes inserted into the posterior cricoarytenoid muscles. In all five canines, obvious abduction of the vocal folds synchronized with inspiration was observed during electrical pacing.

Animals↗
PubMed1987

Regulation of IgE receptor expression on human peripheral blood lymphocytes by lymphocytosis promoting factor (LPF), lectins and dexamethasone.

Using a monoclonal anti-human Fc epsilon R antibody (H107), we found that lymphocytosis promoting factor (LPF), phytohaemagglutinin (PHA-P) and Concanavalin A (Con A) could induce Fc epsilon R, detected by immunofluorescence study, on normal human peripheral blood lymphocytes without IgE. The number of Fc epsilon R bearing lymphocytes was increased by stimulation with 3, 10 and 10 micrograms/ml of LPF, PHA-P and Con A, respectively, from 6.0 +/- 3.0/1000 cells to 26.0 +/- 7.9, 54.0 +/- 6.7 and 24.8 +/- 7.1/1000 cells, respectively. Although the induction of Fc epsilon R occurred neither in the separated T-enriched fraction (TEF) nor the T-depleted fraction (TDF), it recovered when the two fractions were mixed. The cell free supernatants from TEF stimulated with LPF or PHA-P could increase Fc epsilon R(+) cells in TDF, whereas those from TDF failed to increase them in TEF. The results suggest that the induction of Fc epsilon R occurs mainly on B lymphocytes by the soluble factor(s) formed by T cells stimulated with LPF or PHA-P. The induction of Fc epsilon R by stimulants was completely inhibited by 10(-6) M dexamethasone. It was demonstrated that the effects of dexamethasone on lymphocytes were dual: one was on B cells to inhibit responsive increases of Fc epsilon R, and the other was on T cells to suppress the formation of the soluble factor(s) which induced Fc epsilon R on B cells.

Dexamethasone↗
PubMed1986

Calcification in aging canine aortic valve.

Aging changes of aortic valves are thought to underlie the mechanism of calcification, which leads to calcific aortic stenosis in humans. The study of calcification in the aging valvular connective tissue has been hindered by the lack of a suitable animal model. In search of the model, canine aortic valves demonstrated age changes including calcification remarkably similar to those in humans. The mechanism of calcification was studied in the aortic valves of aged Beagles by electron microscopy. Fibroblasts in the canine aortic valves showed the most prominent age changes. The cells accumulated numerous residual bodies and appeared to disintegrate. The resultant membranous cellular degradation products which sequestered in the extracellular space were the nidi of calcification. It appeared that the membrane of cell debris played an important role in calcification. Canine aortic valve is an ideal model for the study of calcification in relation to aging of the valvular connective tissue.

Aging↗
PubMed1985

Sodium orthophosphate hydrate (NA3PO4.12H2O): a new type of human urinary stone.

In a series of electron microscopic studies of human urinary stones, a stone composed of sodium orthophosphate hydrate was identified. The stone was recovered from a patient who succumbed to advanced renal failure. A massive failure of the sodium pump, which cotransports phosphate across the brush border membrane of the proximal tubules is thought to be responsible for such an exceptional stone. This appears to be the first description of sodium phosphate crystal in a human urinary stone. Electron microscopy is a useful tool for stone analysis.

Aged↗
PubMed1985

X-ray microanalysis of urinary stones, a comparison with other methods.

A previous study of urinary stones by a combined electron microscopy demonstrated the potential of scanning electron microscopy and X-ray analysis as an analytic tool for urinary stones. Electron diffraction was chosen for the final confirmation of crystals in the study. Although electron diffraction is highly accurate for this purpose, it is desirable to establish the sensitivity of X-ray analysis for the identification of stone components relative to the more commonly used methods. Eighty six consecutive urinary stones were analyzed by X-ray analysis and the findings were compared with those of X-ray diffraction, infrared spectrometry and chemical analysis. The results indicate that X-ray analysis exceeds X-ray diffraction and infrared spectroscopy in its sensitivity for the identification of stone components several fold. This was largely due to the inability of the latter methods to detect apatite in more than half of the apatite containing stones. The findings in X-ray analysis had the best correlation with chemical analysis, which was applied mainly to the detection of apatite. X-ray analysis is particularly suited for the detection of rare and minor inorganic components of urinary stones such as silica and gypsum, and is obviously one of the most powerful tools for the analysis of urinary stones. Further application of X-ray analysis to urinary stone is likely to discern rare inorganic components of urinary stones overlooked by other methods.

Calcium Oxalate↗
PubMed1985

Placental calcification: ultrastructural and X-ray microanalytic studies.

Calcification is common in human placentas and is widely recognized as a normal part of maturation and aging of this organ. Eleven human placentas were studied by light and electron microscopy to elucidate the mechanism of placental calcification. Earliest mineral deposits were seen along the trophoblastic basement membrane of the chorionic villi undergoing fibrinoid degeneration. Transmission electron microscopic examination revealed crystalline deposits within small membrane-bound vesicles; the latter appear to be derived from degenerating cells and were particularly numerous within the basement membrane. X-ray microanalysis of these deposits revealed calcium and phosphorus peaks and the pattern of calcium hydroxyapatite was noted by electron diffraction. This pattern of calcification, i.e., precipitation of calcium hydroxyapatite in association with extracellular membrane bound vesicles, is similar to that seen in physiologic and pathologic calcifications of other tissues.

Calcification, Physiologic↗