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Biomedical subjects

H Lee

Publications and source records attributed to H Lee.

At least 775 records · Page 43Linked to original sources
PubMed1988

Time-lapse photographic study of neural tube closure defects caused by xylocaine in the chick.

Sequential changes in the morphology of early chick embryos were, for the first time, photographically recorded. Embryos were explanted at stage 8 (four-somite) or 9- (six-somite) of development using New's technique and grown in nutrient medium (thin albumen) with or without a teratologic dose (200 micrograms/ml) of xylocaine. They were photographed using a Nikon Diaphot inverted microscope equipped with both phase-contrast optics and photomicrographic accessories maintained in an incubator. It was found, among other things, that a characteristic neural tube closure defect often seen in the midbrain and anterior portion of the hindbrain of xylocaine (200 micrograms/ml)-treated chick embryos was a consequence of failure of the neural tube to withstand the tension generated by the rapidly expanding cephalic region, which occurred, regardless of the stage at explanation, when corresponding control embryos had advanced to stage 10+ (11-somite) of development.

Abnormalities, Drug-Induced↗
PubMed1988

Antimutagenic activity of extracts from anticancer drugs in Chinese medicine.

The antimutagenic activities of extracts of 36 commonly used anticancer crude drugs from Chinese herbs were studied by using the Salmonella/microsomal system in the presence of picrolonic acid or benzo[a]pyrene to test whether they contain direct or indirect antimutagens. Each crude drug was extracted with boiling water for 2 h, the method which is commonly used by Chinese people to prepare the drug for oral intake. The extracts of Pteris multifida P. showed the highest antimutagenic activity against picrolonic acid-induced mutation. The extracts of 6 other different kinds of Chinese herbs were shown to have a moderate antimutagenic activity against picrolonic acid-induced mutation, and they are: Actinidia chinensis P., Artemisia lavendulaefolia DC. and Crotalaria sessiflora L., Prunella vulgaris L., Paris polyphylla S. and Ampelopsis brevipedunculata T. The extracts of Smilax china L., Prunella vulgaris L. and Actinidia chinensis P. were demonstrated to inhibit the mutagenicity of benzo[a]pyrene completely. The 12 other kinds of extracts of Chinese herbs which had a moderate antimutagenic activity against benzo[a]pyrene were: Pteris polyphylla S., Ampelopsis brevipedunculata T., Duchesnea indica F., Gossypium herbaceum L., Lithospermum erythrorrhizon SZ., Artemisia lavendulaefolia DC., Selaginella doederleinii H., Dianthus superbus L., Centipeda minima ABA., Curcuma zedoaria R., Marsdenia tenacissima WA. and Kalopanax septemlobus K. Among them, there were 5 kinds of crude drugs, Actinidia chinensis P., Artemisia lavendulaefolia DC., Prunella vulgaris L., Paris polyphylla S. and Ampelopsis brevipedunculata T., containing antimutagenic factors against both picrolonic acid- and benzo[a]pyrene-induced mutation.

Antineoplastic Agents, Phytogenic↗
PubMed1988

Induction of chromosomal aberrations in rat bone marrow cells and mutations in Salmonella typhimurium by benz[a]anthracene derivatives.

Benz[a]anthracene (BA) and its derivatives containing methyl and/or ethyl groups in the 7 and/or 12 positions were tested for their ability to induce chromosome aberrations (CA) in rat bone marrow cells and for their mutagenicity to Salmonella typhimurium TA100 or TA98. The incidence of aberrant cells induced by the BA derivatives, given in lipid emulsion as a single-pulse dose of 50 mg/kg body weight into the caudal vein, was in the order: DMBA greater than EMBA greater than MEBA greater than other BA derivatives = control. The alkyl groups, at least 1 methyl group, at the 7 and 12 positions of BA seemed to be necessary to induce CA, although DEBA having ethyl groups at both the 7 and 12 positions of BA did not induce CA. DMBA or EMBA induced not only gaps and breaks but also exchanges and multiple CA, while the CA induced by other BA derivatives consisted of only gaps and breaks. 7MBA and 12MBA which exhibit carcinogenic activity intermediate between that of DMBA and BA induced few CA in the present system. However, the correlation coefficient between the logarithm incidence of aberrant cells and the carcinogenicity index calculated from the data of 9 BA derivatives including both 7MBA and 12MBA was 0.792. The relative mutagenicities of the BA derivatives with TA100 in the presence of hepatic S9 from polychlorinated biphenyl (PCB)-treated rats were in the order: BA greater than 7MBA greater than DMBA greater than 12MBA greater than 7EBA greater than EMBA greater than MEBA greater than 12EBA = DEBA = control. The results with TA98 were essentially the same as those with TA100. The results with TA100 in the presence of hepatic S9 from phenobarbital (PB)-treated rats were in the order: DMBA greater than 12MBA greater than 7MBA greater than 7EBA greater than BA greater than EMBA = MEBA greater than 12EBA = DEBA = control. These findings reveal no obvious relation between the mutagenic activities of the BA derivatives with the PCB-S9 or PB-S9 activating systems and their capacities to induce CA or their reported carcinogenicities. The incidence of CA induced by the dihydrodiols implicated as the metabolic precursors of the active diol epoxide metabolites of several of these BA derivatives was also tested. BA 3,4-dihydrodiol, like BA itself, induced few CA. However, the corresponding dihydrodiols of DMBA, 12MBA and 7MBA, induced relatively high levels of CA.(ABSTRACT TRUNCATED AT 400 WORDS)

Alcohols↗
PubMed1988

A metabolite of the carcinogen 7,12-dimethylbenz[a]anthracene that reacts predominantly with adenine residues in DNA.

Four 7,12-dimethylbenz[a]anthracene--deoxyribonucleoside adducts formed in mouse epidermis in vivo arise from the syn dihydrodiol epoxide metabolite of this carcinogen. With the synthetic syn dihydrodiol epoxide it was possible to identify three of these as deoxyadenosine adducts and to establish their structures. These three adducts account for the large majority of DNA adduct arising from this metabolite in vivo. The in vivo metabolite is unusual, therefore, in that it reacts almost exclusively with adenine residues in DNA while most carcinogen metabolites react preferentially with guanine residues.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1988

Recurrent cutaneous Langerhans cell histiocytosis in infancy.

We report two infants, aged 4 and 9 months, respectively, who had recurrent cutaneous lesions of Langerhans cell histiocytosis confirmed by immunohistochemical and ultrastructural studies. The lesions were confined to the skin and appeared as transient papules on the trunk in both patients. Since neither showed evidence of internal organ involvement or further recurrences of the skin lesions during follow-up periods of 22 and 24 months, respectively, no therapy was given. These cases may be considered as an uncommon benign variant of the Langerhans cell proliferative disorder.

Female↗
PubMed1988

Carbohydrate specificity of the galactose-recognizing receptor of rat peritoneal macrophages.

The galactose-recognizing system of rat peritoneal macrophages mediates the binding and uptake of desialylated blood cells and glycoproteins. To characterize the specificity of this receptor, binding studies were performed with various galactose derivatives as competitive inhibitors and sialidase-treated erythrocytes or asialoorosomucoid as ligands for receptors, which were either membrane-bound or isolated after solubilization. From the results obtained it can be concluded that galactose is recognized via its hydrophobic and/or hydrophilic regions, formed by the accumulation of OH-functions on one side and of H-atoms on the other ("side effect"), whereas the binding partner or the anomeric configuration of galactose has no significant influence. Although it became apparent that not a single hydroxyl group of the sugar is responsible for binding, the hydroxyl at C-4 seems to be most important, followed by the OH-group at C-3. Those at C-1, C-2 and C-6 do not play a great role. This order of importance ("position effect") was found with galactose, derivatized by methylation or otherwise, and with diastereomers of galactose. Whereas the recognition of a single galactose residue leads to weak binding only, an appropriate arrangement of several of these ligands in one molecule results in an enormous increase in the binding strength of each galactose residue. This "cluster effect" was observed not only with membrane-bound but also with solubilized receptor. However, the binding of asialoorosomucoid by the latter was better inhibited with free galactose, when compared with the membrane-bound receptor.

Animals↗
PubMed1988

Review of primary tumors of the diaphragm.

A case report of a man with a huge, left-sided diaphragmatic rhabdomyosarcoma is presented. The mass was attached to the lung, pericardium, left phrenic nerve, sternum, and chest wall. Enbloc resection of the tumor was done with primary repair of the diaphragmatic defect. Only three reported cases of primary diaphragmatic rhabdomyosarcoma were found in the literature.

Diaphragm↗
PubMed1987

The hemodynamic response of the conscious pregnant guinea pig to nicotine.

The hemodynamic response to continuous intravenous infusion of nicotine, at 4.5 and 18 micrograms/min, was measured using radiolabeled microspheres in nine chronically catheterized pregnant guinea pigs. These gave serum nicotine levels of 72.3 +/- 6.6 ng/ml and 315 +/- 32 ng/ml (mean +/- SEM), respectively. During low-dose nicotine infusion there was no significant change in cardiac output, its distribution, or uteroplacental blood flow. During high-dose nicotine infusion, cardiac output fell from 257.8 +/- 30.9 ml/min to 212.7 +/- 19.3 ml/min (p less than 0.05) and uteroplacental blood flow fell from 31.2 +/- 3.1 ml/min to 22.3 +/- 2.4 ml/min (p less than 0.05). During control, low-dose, and high-dose periods, serum epinephrine levels rose from control value of 60.2 +/- 2.6 to 98.9 +/- 35 and 1200 +/- 295 pg/ml (p less than 0.05 low dose versus high dose) and serum norepinephrine levels did not change significantly during nicotine infusion. Hence at nicotine levels 20 times but not at two to five times those seen in smokers, modest reductions in cardiac output and uteroplacental blood flow were observed.

Animals↗
PubMed1987

Phenotypic heterogeneity and recycling capacity of natural killer cells in normal human pregnancy.

Natural killer (NK) cells have the ability to kill a variety of target cell types and the possibility that such cells could mount an effective attack on the developing fetus has not been discounted. The present study extends previous work showing that maternal NK reactivity against K562 target cells (TC) is reduced during pregnancy. Here we demonstrate using cytotoxicity assays at both the population and single cell level that, although depressed in number, maternal NK cells exhibiting the capacity to kill K562 TC are as lytically active in their ability to recycle and destroy multiple TC as NK cells from non-pregnant females. Moreover, two colour immunofluorescence analysis of the NK cell-associated markers Leu-7 and Leu-11b indicates that, in addition to a reduction in the absolute number of TC conjugate-forming cells, pregnant females present in their peripheral blood a larger proportion of TC-binding Leu-7+11- cells. These cells may be lytically immature. Small changes in NK cell profile and activity in maternal peripheral blood may be indicative of much more significant changes at the feto-maternal interface. It is, however, clear that pregnant females retain a population of highly active NK cells, thus minimising the possibility of immunocompromise.

Adult↗
PubMed1987

Cytotoxic activity and phenotypic analysis of natural killer cells in early normal human pregnancy.

Peripheral blood lymphocytes taken from healthy women planning a pregnancy and then at various intervals up to the 16th week of pregnancy were assayed for natural killer (NK) cell activity against K562 target cells both in a 51Cr-release assay and in a single cell cytotoxicity assay. Results indicated a depression in NK activity from the earliest stages of pregnancy. The target binding capacity of the effector cells remained unimpaired up to 16 weeks, but a significant reduction in the post-binding lytic potential was observed, which parallelled the drop in cytotoxicity as assayed by the 51Cr-release method. The ability of individual effector cells to recycle and kill multiple targets remained essentially unimpaired. Analysis of lymphocyte subpopulations using the monoclonal antibodies anti-Leu-7 and anti-Leu-11b, which recognize NK cell-associated antigens, showed a significant reduction in the proportion of the mature, lytically active Leu-7-11+ cells capable of both binding and lysing K562 target cells. The suggestion that the depression in cytotoxicity may be associated with the reduction in the Leu-7-11+ subpopulation is supported by the high correlation levels observed between the proportion of Leu-7-11+ cells and target cell lysis.

Antibodies, Monoclonal↗
PubMed1987

Aerosol inhalation teaching device.

To facilitate teaching of inhalation technique to children, we have developed an aerosol inhalation teaching device by modifying the jacket of a canister nebulizer so that inhalation is accompanied by a horn sound and a flashlight is turned on when the canister is actuated. The device was evaluated in 33 children with asthma who had either never used a canister nebulizer (13 patients) or used incorrect technique (20 patients). The inhalation technique was first taught with conventionally, that is, verbal directions and demonstration with a canister nebulizer for 10 minutes. Only 10 (30%) of 33 children learned the technique. The remaining 23 were then taught with the special device. Twenty of 23 learned the technique within 10 minutes, but three others took longer. In a second study, 22 children, 11 of whom were beginners and 11 incorrect users, were instructed with the teaching device from the beginning. Seventeen (77%) learned the technique within 10 minutes; five others took longer. Most children can be taught the aerosol inhalation technique with this easily constructed device.

Adolescent↗
PubMed1987

Metabolism and DNA adduct formation of benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene in fish cell lines in culture.

The metabolic activation of the carcinogens benzo[a]pyrene (BP) and 7,12-dimethylbenz[a]anthracene (DMBA) was examined in cell lines derived from bluegill fry (BF-2), rainbow trout (RTG-2) and brown bullhead (BB). All three cell lines metabolized BP (0.5 microgram/ml medium) almost completely to water-soluble metabolites within 120 h, but the maximum amount of BP bound to DNA ranged from only 5 pmol/mg DNA in the BF-2 cells to 17 in the BB cells and 44 in the RTG-2 cells. The major BP-DNA adduct in the BB and BF-2 cells was that formed by reaction of (+)-anti-BP-7,8-diol-9,10 epoxide [(+)anti-BPDE] with deoxyguanosine. This adduct was also present in the RTG-2 cell DNA, but there were larger amounts of unidentified polar BP-DNA adducts. Exposure of the cells to [3H]BP-7,8-diol, a metabolic precursor of (+)anti-BPDE, resulted in binding of 1.5, 12 and 35 pmol BP per mg DNA in the BF-2, BB and RTG-2 cells, respectively. More than 90% of the BP-7,8-diol added to the BF-2 cultures was recovered as a glucuronic acid conjugate, but the RTG-2 cells formed more glutathione conjugates than glucuronide conjugates. The BB cells formed both types of conjugates at a slower rate for more than 75% of the 7,8-diol was recovered unchanged after 24 h. The three cell lines differed in the proportion of a 0.1 microgram/ml dose of DMBA metabolized in 48 h: the values ranged from 47% in the BF-2 cells to 78% in the BB cells and 97% in the RTG-2 cells. The amount of DMBA bound to DNA ranged from 4.7 to 8.6 pmol/mg DNA in the three cell lines: DMBA-3,4-diol-1,2-epoxide (DMBADE) adducts were present in the BB cell DNA, but no significant amounts of DMBADE-DNA adducts were detected in the RTG-2 or BF-2 cell DNA. These results demonstrate that fish cell cultures can activate BP to an ultimate carcinogenic metabolite, (+)anti-BPDE, but the level of binding of this metabolite to DNA is much lower than that which occurs in rodent embryo cell cultures. In BF-2 cell cultures formation of BP-7,8-diol-glucuronide effectively prevents the activation of this diol to (+)anti-BPDE. A substantial proportion of the BP-7,8-diol is also metabolized to glucuronide and glutathione conjugates in BB and RTG-2 cells. DMBA also binds to DNA at very low levels in these fish cell cultures. Thus effective conjugation of diols and their metabolites by fish cell lines appears to greatly reduce metabolic activation of hydrocarbons through the bay-region diol epoxide pathway that predominates in mammalian cell cultures.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1987

A new method for the preparation of 'double-fixed', quick-frozen, freeze-substituted cells for whole-cell transmission electron microscopy.

A method is described in which quick-frozen, freeze-substituted, cultured cells can be prepared for whole-cell transmission electron microscopy (WCTEM). This method is simple and reliable and can be carried out in most laboratories without special equipment. Cells grown of Formvar-carbon-coated nickel grids are quick-frozen in Freon 22, freeze-substituted in an ethanolic solution of glutaraldehyde, post-fixed in osmium tetroxide and critical-point-dried. The quality of ultrastructural preservation using this 'double fixation' protocol is comparable to that of conventional WCTEM. However, the combination of quick-freezing and WCTEM has the decided advantage over conventional WCTEM in that cellular activities are arrested almost instantaneously. Thus, this new method could potentially yield a more faithful representation of cytoarchitecture and is especially useful for studies on the structural basis of rapid cytoplasmic events which may remain undetected when using conventional fixation methods.

Cells, Cultured↗
PubMed1987

Some Properties of Extracellular Acetylxylan Esterase Produced by the Yeast Rhodotorula mucilaginosa.

The red yeast Rhodotorula mucilaginosa produced an esterase that accumulated in the culture supernatant on induction with triacetin. The enzyme was specific for substrates bearing an O-acetyl group, but was relatively nonspecific for the rest of the molecule, which could consist of a phenol, a monosaccharide, a polysaccharide, or an aliphatic alcohol. The esterase was more active against acetylxylan and glucose beta-d-pentaacetate than were a number of esterases from plant and animal sources, when activities on 4-nitrophenyl acetate were compared. The enzyme exhibited Michaelis-Menten kinetics and was active over a broad pH range (5.5 to 9.2), with an optimum between pH 8 and 10. In addition, the enzyme retained its activity for 2 h at 55 degrees C. The yeast that produced the enzyme did not produce xylanase and, hence, is of interest for the production of acetylxylan esterase that is free of xylanolytic activity.

Journal Article↗
PubMed1987

Evaluation of inhalation aids of metered dose inhalers in asthmatic children.

Many patients have incorrect aerosol inhalation technique with metered dose inhalers (MDI). Several inhalation aids have been developed and marketed for these patients. Even those who have correct inhalation technique may benefit from these devices. We compared bronchodilator efficacy of two puffs of albuterol aerosol administered either directly from a MDI mouthpiece, or from an inhalation aid (InspirEase, Aerochamber, Aerosol Bag) in 20 children who had previously demonstrated proper inhalation technique. The children received two puffs of aerosol from a MDI in each of two modalities tested each day on four different days (double blind). One modality contained albuterol aerosol and the other placebo. Pulmonary function was tested before and at 15, 30, 60, 120, and 180 minutes after treatment. Forced expiratory volume in 1 second (FEV1) increased similarly after all four modes of administration. Six patients who had incorrect inhalation technique benefited from the three inhalation aids. The aerosol bag and InspirEase produced slightly greater bronchodilator response than the Aerochamber. The inhalation aids are useful devices for those who have incorrect inhalation technique, but those who have correct technique do not derive any benefit from these devices.

Adolescent↗