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Biomedical subjects

H S Lin

Publications and source records attributed to H S Lin.

At least 127 records · Page 7Linked to original sources
PubMed1982

Differentiation of various mononuclear phagocyte colony-forming cells by hypotonic lysis.

Various classes of murine mononuclear phagocyte colony-forming cells (CFU) present in peritoneal exudate, alveolar spaces, and blood are capable of extensive proliferation and form colonies in vitro. In this study, the sensitivity to hypotonic lysis of the proliferative capacity of various classes of mononuclear phagocyte CFC as well as three cell lines was investigated. The results showed that alveolar CFC (AL-CFC) and a macrophage cell line J774 are most resistant to hypotonic conditions, and the committed stem cells for both granulocytes and macrophages (GM-CFC) and blood monocytes (BL-CFC) are most sensitive to hypotonic conditions. Within 7 min all GM-CFC and BL-CFC are killed but less than 5% of AL-CFC are killed. Peritoneal exudate CFC (PE-CFC) displayed intermediate sensitivity since 50% of them were killed within 7 min in the hypotonic conditions. These data suggest that various classes of mononuclear phagocyte CFC can be distinguished from each other by their ability to resist hypotonic lysis.

Animals↗
PubMed1981

Conversion of monocytes to cells capable of anchorage-independent growth in vitro.

We investigated the time-course involved in the conversion of mouse blood monocytes in vitro in cells capable of anchorage-independent growth. Two criteria were used to define when monocytes were fully converted to cells similar to mononuclear phagocytes present in inflammatory exudate, such as thioglycollate medium (TM)-elicited peritoneal exudate. They were the production of high levels of plasminogen activators and an ability to undergo anchorage-independent growth. Resident peritoneal macrophages were used as controls and for comparison. Our studies indicated that monocytes, but not resident peritoneal macrophages, could be converted to cells similar to TM-elicited mononuclear phagocytes after 2 d in culture.

Agar↗
PubMed1981

Effect of epinephrine on prostaglandin E2 and cyclic AMP levels in gingiva of patients with chronic periodontitis.

The levels of prostaglandin E2 (PGE2) and cyclic AMP (cAMP) in human gingival samples were determined by means of radioimmunoassay after incubation with epinephrine (10(-6)M) at different time intervals. The levels of PGE2 and cAMP reached a maximum in the control and hormone treated samples after 80 and 40 minutes, respectively. Epinephrine seemed to affect a lesser increase in PGE2 and a greater increase in cAMP values in gingival tissues when compared with control samples. When the data were analysed, there was statistically significant differences found between the control and hormone treated samples regarding both PGE2 and cAMP.

Chronic Disease↗
PubMed1981

Metabolism of 1,3-bis(2-chloroethyl)-1-nitrosourea by rat hepatic microsomes.

The in vitro metabolism of the anticancer agent 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) has been studied in male Fischer 344 rat liver microsomal preparations. The previously identified product. 1,3-bis(2-chloroethyl)urea (BCU), has been shown to be the major metabolite. Stable isotope labeling and mass spectral analysis of isolated metabolites indicate that BCU is formed exclusively from the metabolic denitrosation of BCNU. The rate of BCNU chemical decomposition in rat liver microsomal preparations deficient in NADPH and the metabolic disappearance rate in preparations containing added NADPH were measured and compared with the measured rate of metabolic formation of BCU under the same conditions. The rate of NADPH-dependent BCNU metabolism and BCU formation are equal within experimental error. BCNU was found to inhibit the rat liver 9000 g supernatant metabolism of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU).

Animals↗
PubMed1981

The relationship between inflammation and cAMP level in human gingiva.

The levels of cAMP were measured by means of radioimmunoassay in 20 gingival samples free from inflammatory cells and 43 samples with moderately dense and dense aggregations of inflammatory cells. The average values were found to be 340 +/- 44 and 552 +/- 59 pmol/gm wet tissue, respectively. The increase in cAMP levels in inflammation is suggested to be modulated by an increase in endogenous prostaglandin synthesis and could be one of the natural mechanisms by which the host protects itself from dangerous consequences of unregulated immune response.

Cyclic AMP↗
PubMed1981

Biosynthesis of prostaglandin E2 and F2 alpha in gingiva of patients with chronic periodontitis.

The biosynthesis of radioactive prostaglandin E2 (PGE2) and F2 alpha from (1-14C) arachidonic acid has been demonstrated in the microsomal fraction of gingiva of patients with chronic periodontitis in vitro. 14C corresponding to unmetabolized arachidonic acid in three separate incubations was 83, 66, and 83%, and that corresponding to both PGE2 and PGF2 alpha was 8, 22, and 9% of the total radioactivity recovered after chromatography. The ratios of PGE2 to PGF2 alpha were found to be 6:1, 6:1, and 3:1, respectively.

Arachidonic Acids↗
PubMed1981

Prostaglandins in gingiva of patients with periodontal disease.

Prostaglandin E and F were measured simultaneously by radioimmunoassay in extracts of gingiva of patients with chronic periodontal disease. The mean values of PGE and PGF in 27 gingival samples were 42.2 +/- 4.9 and 52.6 +/- 6.8 pmol/gm wet tissue weight, respectively. The correlation coefficient (r) between the two groups of PGs was a positive 0.42, significant at P less than 0.05.

Adult↗
PubMed1980

Protein mediated chemical reactions of chloroethylnitrosoureas.

The rates of chemical degradation of chloroethylnitrosoureas in serum are significantly higher than in aqueous buffer at the same pH and temperature. This rate enhancement is shown to be produced by a non-specific protein mediated chemical reaction that involves the formation of a protein-chloroethylnitrosourea (CENU) complex. Purified human serum albumin catalyzed reactions have been studied and Vm- and Km-values obtained for 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea (MeCCNU). The rate of 1-(2-chloroethyl)-3-(2,6-dioxo-3-piperidyl)-1-nitrosourea (PCNU) decomposition is not enhanced by serum proteins. Formation of a protein-BCNU complex can be inhibited by salicylic acid and dodecanoic acid, two compounds that have a high albumin binding affinity. Reaction product analysis indicates that the only BCNU reaction catalyzed by albumin is conversion to active 2-chloroethylazohydroxide and 2-chloroethylisocyanate intermediates. Formation of these reactive species at the protein surface leads to a high proportion of covalent bond formation to the protein. These results emphasize the complex and structure specific factors that may affect the biodistribution, antitumor activity and toxicity of members of the chloroethylnitrosourea class of cancer chemotherapeutic agents.

Alkylating Agents↗
PubMed1980

Enhancement of the growth of blood monocytes in agar cultures by haemolysates.

Mouse blood monocytes grow well in liquid but poorly in agar medium. In this study the effect of haemolysate on the clonal growth of blood monocytes in agar cultures was investigated. The results suggested that haemolysate from mouse or rat red blood cells contains a factor(s) that can render the murine blood monocytes able to grow well in agar culture (anchorage-independent growth). The mechanism of action of the enhancing factor(s) is discussed.

Animals↗
PubMed1980

Peritoneal exudate mononuclear phagocyte colony-forming cells: their proliferative state in vivo and sensitivity to cytotoxic agents.

We investigated the proliferative state of peritoneal exudate macrophage colony-forming cells (PE-CFC) by exposing them to [3H]thymidine with a high specific activity in vitro and by administering cytosine arabinoside and methotrexate in vivo. Since [3H]TdR had no appreciable killing effect on PE-CFC and since the drug treatment caused no reduction in the appearance of PE-CFC, we concluded that the majority of PE-CFC, if not all, are not in active cell cycle. The production of PE-CFC was, however, suppressed by the administration of nitrogen mustard, cyclophosphamide, BCNU and vinlastine.

Animals↗
PubMed1980

Cyclic AMP and prostaglandins in periodontal disease.

Since inflamed gingiva contain significantly higher levels of endogenous PGs (8) and cAMP than normal gingiva and since exogenous PGs have been shown to stimulate endogenous cAMP synthesis in gingiva in vitro, we suggest that the increase in the endogenous cAMP levels found in the inflamed tissue may be attributable to the increase in endogenous PGs. Cyclic AMP has been reported to stabilize the lysosomal membranes of inflammatory cells; hence, the increase in cAMP formation in inflammation seems to be associated with an endogenous compensatory protective mechanism which is able to stop immune or allergic reactions (9, 10).

Chronic Disease↗
PubMed1979

Secretion of plasminogen activator by bone marrow-derived mononuclear phagocytes and its enhancement by colony-stimulating factor.

We have studied the production of plasminogen activator (PA) by mononuclear phagocytes derived from mouse bone marrow precursor cells (CFU-C) in culture. Bone marrow-derived macrophages (BMDM) obtained after 6-8-d cultivation in a liquid medium containing L-cell-conditioned medium (LCM), a source of colony stimulating factor (CSF), showed a high level of fibrinolytic activity comparable to that of thioglycollate medium-induced peritoneal macrophages (TPM) and at least 20-fold higher than that of resident peritoneal macrophages (RPM). Fibrinolysis was a result of active secretion of PA into the culture medium and plaques of caseinolysis could be detected by an overlay assay over all macrophage colonies formed after cloning of bone marrow cells in culture. When the fibrinolytic activity of BMDM harvested at different times was investigated, it was found that the level of PA activity of a given BMDM population correlated well with the incidence of cells (5-15 percent) able to proliferate and form colonies in agar after 7-14 d, somewhat more slowly than CFU-C. This correlation between the level of PA secretion and the incidence of agar colony-forming cells was also found with other mononuclear phagocyte populations. Active fibrinolysis and slow growing colony-forming cells were observed at the same time as adherent macrophages appeared, 2-3 d after the start of bone marrow culture, they persisted for 10 d before declining. Some of the factors which influenced PA production by BMDM were examined. Fibrinolysis could be enhanced two- to fourfold by exposing the cells for 4 h to concanavalin A (Con A), to medium conditioned by Con A-stimulated spleen cells and to LCM, but not by phagocytosis of latex particles. The substance in LCM that stimulated PA production appeared to be identical to CSF. Mononuclear phagocyte targets differed in their response to LCM, which stimulated fibrinolysis readily in BMDM, to a lesser extent in TPM and not at all in RPM. We conclude that CSF stimulates both proliferation and fibrinolytic activity in BMDM and that the level of macrophage activation, as defined by PA production, can be further enhanced by lymphokines. Induction of PA in BMDM provides a rapid and sensitive assay for measuring the activity of CSF and defining its role in macrophage activation.

Animals↗
PubMed1979

Cytochemical studies on cytoplasmic granular elements in the hamster pineal gland.

The pineal gland of adult golden hamsters (Mesocricetus auratus) was studied by various cytochemical methods at the electron microscopic level: (1) the modified chromaffin reaction specific for 5-hydroxytryptamine (5-HT), (2) argentaffin reaction, (3) zinc-iodide-osmium (ZIO) mixture reaction and (4) acid phosphatase reaction. In the pinealocytes, the dense-cored vesicles (80-160 nm in diameter) show both chromaffinity and argentaffinity, while the population of dense bodies (150-400 nm in diameter) is reactive to ammoniacal silver solution and ZIO mixture but not to the modified chromaffin reaction. After incubation for demonstration of acid phosphatase activity, reaction products are localized in some, but not all, of the dense bodies, in some of the small vesicles in the Golgi region and in one or two inner Golgi saccules. In nerve fibers in the pineal gland, small granulated vesicles are also reactive to the modified chromaffin reaction and ZIO mixture. Based upon these cytochemical results the following conclusions have been reached: (1) dense cored vesicles in the pinealocytes and small granulated vesicles in the nerve fibers of the hamster pineal gland contain 5-HT, and (2) the population of dense bodies in the pinealocytes is heterogeneous, some are lysosomes and the other are possibly the granules responsible for the secretion of pineal peptides.

Animals↗
PubMed1979

A dense-cored filamentous body in Leydig cells of the golden hamster.

A unique cytoplasmic structure has been observed in Leydig cells of the golden hamster. It consists of a laminar core made up of electron dense material surrounded by a filamentous matrix of lower density, and is tentatively called a dense-cored filamentous body (DCFB). DCFBs vary in overall size and in configuration of the centrally disposed dense lamina. They are typically located in the vicinity of the centrosome and the Golgi complex. The body has no limiting membrane, and may be in contact with virtually every type of organelle. The DCFB is well developed in active Leydig cells, whereas it is small in the quiescent stage of the secretory cell. It is likely that the DCFB is a constant organelle in the hamster Leydig cell and may be involved in the physiological function of the Leydig cell, which remains to be specified.

Animals↗
PubMed1979

Ultrastructural localization of monoamines in nerve fibers of the pineal gland in golden hamsters.

Nerve terminals in the pineal glands of control, parachlorophenylalanine (PCPA)-, reserpine- and nialamide-administered hamsters were studied with glutaraldehyde-dichromate (GD) and formaldehyde-glutaraldehyde-dichromate (FGD) techniques in the electron microscope. In control pineals treated with the FGD or GD technique, clusters of electron dense reactive particles with a diameter of 20-30 nm, and mainly located in the perivascular space, were identified as dense cores of the small granulated vesicles (SGVs) in the pineal nerve fibers. After the administration of PCPA, the reactive cores were greatly decreased in number in the FGD-treated pineal blocks, whereas a lot of clusters of reactive cores were observed in the perivascular space in GD-treated specimens. After reserpine treatment, no reactive structures were revealed by GD or FGD technique. Reactive cores appeared to be increased in number and in electron density in GD- or FGD-treated pineals of hamsters after administration of nialamide. From the observations, it is concluded that the dense cores of SGVs in the pineal nerve fibers contain both primary catecholamines and 5-hydroxytryptamine although it was not determined whether both amines are located in the same or separate vesicles.

Animals↗