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H S Lin

Publications and source records attributed to H S Lin.

At least 91 records · Page 5Linked to original sources
PubMed1988

Development and characterization of monoclonal antibodies to murine macrophage colony-stimulating factor.

The macrophage-specific CSF (CSF-1), purified from murine L cell-conditioned medium, supports the in vitro proliferation and survival of various murine mononuclear phagocyte colony-forming cells. In this report we describe the production and functional characterization of two monoclonal antibodies (mAb) to CSF-1 obtained from rat X rat hybridomas. These two mAb are functionally distinct and recognize different epitopes on CSF-1. The mAb 5A1 binds to and inhibits the biologic function of CSF-1, and the second mAb (D24) binds CSF-1 but does not neutralize its biologic activity. The mAb 5A1 inhibits colony formation of tissue mononuclear phagocyte colony-forming cells as well as the committed bone marrow stem cells for both granulocytes and monocytes. The extent of colony inhibition by mAb 5A1 is dependent on the tissue origin of colony-forming cells. CSF-1 complexed with mAb 5A1 does not bind to its cell surface receptor of peritoneal exudate macrophages, and mAb 5A1 does not complex with cell-bound CSF-1. Although both bone marrow cell-derived macrophages and J774.1 macrophages bind CSF-1, mAb 5A1 inhibits the proliferation of only bone marrow cell-derived macrophages. The non-neutralizing mAb D24 does not block binding of CSF-1 to its cellular receptor, and it recognizes cell-bound CSF-1.

Animals↗
PubMed1987

A centrosomal inclusion (striped nebulous body) in pinealocytes of the golden hamster.

Electron microscopy has revealed the presence of a special cytoplasmic body in the centrosomal area of pinealocytes of the golden hamster, Mesocricetus auratus. It consists of branching electron-dense ribbons embedded in a flocculent matrix of moderate electron density, and is tentatively named the 'striped nebulous body' (SNB). The dense ribbon usually appears as a thick band accompanied by a parallel thin one to one side. The SNB is not bounded by a membrane, and is roughly round or kidney-shaped. Closely associated with the SNB are centrioles, microtubular sheaves and striated fibrils, the latter two being centriolar derivatives. The observations suggest that the SNB might be formed by the amalgamation of these microtubular sheaves and striated fibrils. In golden hamsters, pinealocytes often have multiple centrioles and centriolar derivatives. The SNB of adult hamsters is seen in the pinealocytes of both sexes, irrespective of the season of the year and the activity of the pineal gland. The functional significance of this body remains to be studied.

Animals↗
PubMed1987

Effect of effervescent buffered aspirin on prostaglandin synthesis by human gingival fibroblasts.

Cultured human gingival fibroblasts were incubated with 14C-arachidonic acid (AA) at 37 degrees C for 2 hours. The metabolites formed were extracted from the cell-free medium in methanol, separated and identified by thin layer chromatography, using two solvent systems that allowed resolution of cyclooxygenase and lipoxygenase products. The predominant cyclooxygenase products were PGE2 and 6-keto-PGF1 alpha. PGA2, PGF2 alpha, PGD2, 15-keto-PGE2, TXB2 were also detected in smaller amounts. No detectable radioactivity corresponding to lipoxygenase products 5-HETE, 12-HETE, and 15-HETE was found. Incubation of fibroblasts with effervescent buffered aspirin (EBA) (.02%, .04%, .06%), or sodium bicarbonate, citric acid and aspirin, individually, (in concentrations equivalent to those present in EBA) resulted in stimulation of synthesis of PGs except PGE2 which was inhibited by EBA and aspirin.

Arachidonic Acid↗
PubMed1987

Brain L-glutamate decarboxylase: purification and subunit structure.

Glutamate decarboxylase (GDCase; L-glutamate-1-carboxy-lyase, EC 4.1.1.15) was purified from whole rat brain approximately equal to 1300-fold to apparent homogeneity with a specific activity of 2.4 units per mg of protein by a combination of column chromatographies on DEAE-cellulose, hydroxylapatite, and gel filtration, and preparative nondenaturing polyacrylamide gel electrophoresis. The purified preparation contained a single protein band that comigrated with GDCase activity in three diverse analyses: nondenaturing regular (5%) and gradient (3.6-25%) polyacrylamide gel electrophoresis and isoelectric focusing at pH 4-7. The native molecular mass was calculated to be 120 +/- 10 kDa from gradient polyacrylamide gel electrophoresis and 110 +/- 10 kDa from gel filtration. Under the treatment with NaDodSO4 and 2-mercaptoethanol, GDCase dissociated into two subunits of 40 +/- 2 and 80 +/- 4 kDa, as estimated from NaDodSO4 gel electrophoresis. However, only a 40-kDa subunit was detected when GDCase was treated with 4 M urea plus NaDodSO4 and 2-mercaptoethanol, suggesting that the 80-kDa subunit is the dimer of the 40-kDa subunit. In immunoblotting, polyclonal antibodies against GDCase reacted with both 40- and 80-kDa subunits, while monoclonal antibody reacted with only 80-kDa subunits. The isoelectric point of the native enzyme was 5.4. The Km for glutamate was 1.59 X 10(-3) M. In addition to L-glutamate, cysteine sulfinic acid was also decarboxylated at approximately equal to 10% of the rate of glutamate. The pH optimum was fairly broad, with a maximum at approximately equal to 7.3. The enzyme was strongly inhibited by carbonyl-trapping agents, sulfhydryl reagents, thiol compounds, and beta-methylene-DL-aspartate.

Animals↗
PubMed1987

Prostaglandin synthesis by squamous carcinoma cells of head and neck, and its inhibition by non-steroidal anti-inflammatory drugs.

The purpose of this study was to determine the nature and amounts of prostaglandins (PGs) produced by squamous carcinoma cells (SCC) and the sensitivity of these cells to non-steroidal anti-inflammatory drugs. SCC of four lines of the tongue and one line of facial epidermis of humans were incubated in phosphate buffer solution with 14C-arachidonic acid (AA). Radioactive metabolites in aqueous methanol were chromatographed on Sep-Pack C18 cartridges, separated and quantitated by means of TLC, autoradiography, and liquid scintillation counting. The results showed that cyclooxygenase products, PGs, were the major products formed by all cell lines, and PGE2 was predominant among the PGs detected. Two radioactive bands corresponding to PGF2 alpha and three unseparated standards of PGA2, 15-keto-PGE2, and 13,14-dihydro-15-keto-PGE2 were detected in lesser amounts. Very small amounts of the lipoxygenase products 12- and 15-HETE were found. The concentrations of indomethacin, ibuprofen and aspirin required to inhibit 50% of PGE2 synthesis (IC50) by SCC lines were .008-.080, .080-6.4 and 32-88 microM, respectively.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1987

Fine structural and cytochemical studies on the hamster subcommissural organ.

The subcommissural organ (SCO) of the golden hamster (Mesocricetus auratus) was studied by conventional electron microscopy, freeze-fracture technique, zinc-iodide-osmium (ZIO) and acid phosphatase cytochemical reactions. The ultrastructure of hamster SCO cells shows a few flattened cisternae of rough endoplasmic reticulum (ER) without dilated ones in the cytoplasm. The Golgi apparatus is very well developed. Freeze-fracture studies also indicate only short profiles of flattened ER in the cytoplasm endorsing the absence of dilated ER cisternae. After the treatment with ZIO mixture, reaction products were observed over flattened cisternae of the ER and the nuclear envelope. The Golgi apparatus was also reactive toward the ZIO mixture. Acid phosphatase activities are localized in the inner one or two saccules of the Golgi apparatus and dense bodies. From these results we suggest that (1) hamster SCO cells do not accumulate secretory material in the cytoplasm in the form of discrete secretory granules or dilated cisternae of ER, and (2) hamster SCO cells may possess extremely high secretory activity or may not be actively involved in secretory function at all as in rats or other rodents.

Acid Phosphatase↗
PubMed1987

Immunocytochemical studies on prolactin cells in the adenohypophysis of the golden hamster.

Mammotrophs or prolactin (PRL) cells were identified in the adenohypophysis of adult golden hamsters by immunocytochemical techniques with a polyclonal anti-PRL, that was proved to be specific to PRL by the dot immunoblotting test. Postembedding immunostaining was performed on Araldite thin sections by immunoperoxidase and immunogold methods. PRL cells were classified into three types according to the different size of the secretory granules. The Type A cells were usually small and angular or oval in shape, and had secretory granules ranging in diameter from 100-230 nm, and showed poorly developed organelles. The Type B and C cells were larger and round or ovoid in shape, contained larger granules, 230-280 nm and 280-570 nm, respectively, and displayed well developed organelles. Immunoreactive PRL cells in the male pituitaries were far less numerous than in the nonpregnant female glands, and were mostly of the Type A and B, whereas in the female the Type C and B cells predominated. In pregnant females, Type C cells became activated and increased in number, while the other two types decreased in proportion. In lactating females, Type A and B cells significantly increased in number at the expense of the Type C cells; meanwhile, the exocytosis of secretory granules was frequently found in all types of PRL cells. The present findings suggest that Type C and B PRL cells, especially the former, are potent in producing and releasing PRL and highly responsive to various physiological stimuli, while Type A cells are probably relatively inert in synthetic activity.

Animals↗
PubMed1987

Self-renewal of pulmonary alveolar macrophages: evidence from radiation chimera studies.

Radiation-induced chimeric mice were used to study the origin of pulmonary alveolar macrophages. Unlike in other studies, these radiation chimeras were prepared by using a special fractionated irradiation regimen to minimize the killing of alveolar macrophage colony-forming cells, putative local stem cells. For this study CBA mice with or without T6 chromosome marker were used. Under this experimental condition, the majority of alveolar macrophages in mitosis are of host origin even after 45 weeks. These data suggest that alveolar macrophages are a self-renewing population under normal steady-state conditions.

Animals↗
PubMed1987

Immunocytochemical identification of growth hormone cells in the adenohypophysis of the golden hamster.

Somatotrophs or growth hormone (GH) cells in the adenohypophysis of golden hamsters were identified by immunocytochemical staining with polyclonal rabbit anti-human GH. They were oval or columnar in shape, and had secretory granules of two size ranges, 90-150 nm and 280-320 nm, which were present in the same cells; no subtypes of GH cells were observed. Secretory granules were located in the peripheral portion of the cytoplasm or concentrated at the vascular pole of the cell. Flattened cisternae of the rough endoplasmic reticulum in parallel array and a moderately developed Golgi apparatus were often found in the cytoplasm. No sex difference was noticed in the population ratio of GH cells. Immunocytochemical staining with anti-GH or anti-prolactin (PRL) antibodies on separate adjacent sections revealed that the GH and PRL were stored in two different cell types.

Animals↗
PubMed1987

Three dimensional visualization of the Golgi apparatus and endoplasmic reticulum in the subcommissural organ cells with high voltage electron microscopy.

Fine structure and stereo-images of the Golgi apparatus and endoplasmic reticulum (ER) in the subcommissural organ (SCO) cells were visualized by the application of zinc-iodide osmium tetroxide (ZIO) impregnation, conventional electron microscopy and high voltage electron microscopy (HVEM). The Golgi apparatus in the SCO cells of rats, gerbils and hamsters consisted of flattened saccules stacked in parallel array. It showed a selective staining toward ZIO mixture and might form a complex network of tubular structures because of the presence of numerous fenestrations in the flattened Golgi saccules. The cytoplasm of the SCO cells in the rat and gerbil was crowded by dilated cisternae of the ER with a few flattened profiles. In the hamster SCO cells, however, the dilated cisternae of the ER were not observed. Flattened cisternae of ER in all species studied showed a positivity for ZIO impregnation and formed a complex tubular network, whereas dilated cisternae of the ER in the rats and gerbils did not show any reactivity. It was thus determined that the observation of thin and thick sections selectively stained with appropriate reagent for defined cellular organelles under conventional electron microscopy and HVEM offered valuable information about three-dimensional organization of the cell. A definite species-specific variation of SCO ultrastructure and cytochemistry was also demonstrated.

Animals↗
PubMed1986

Production and characterization of polyclonal and monoclonal antibodies to rat brain L-glutamate decarboxylase.

Specific monoclonal and polyclonal antibodies to rat brain glutamate decarboxylase (GAD) were produced and characterized. Polyclonal antibodies against GAD were raised in rabbits by injecting a total of 70-210 micrograms of purified GAD i.m. The specificity of anti-GAD serum was established from a variety of tests including Ouchterlony immunodiffusion, immunoelectrophoresis, immunoprecipitation, dot immunoassay, ELISA tests and Western immunoblottings. In immunodiffusion and immunoelectrophoresis tests using partially purified GAD preparations and anti-GAD serum a single, sharp precipitin line corresponding to GAD activity was obtained. Quantitative immunoprecipitation of GAD activity was achieved using anti-GAD IgG and Staphylococcus aureus. Specificity of the antiserum was further indicated from a dot immunoassay and ELISA tests in which the intensity of the reaction product was proportional to the amount of GAD protein present. In the Western immunoblotting experiments using partially purified GAD preparations only two protein bands corresponding to the position of the two subunits of GAD were stained by anti-GAD IgG, further supporting the specificity of polyclonal antibodies against GAD. In addition to polyclonal antibodies, several specific GAD-antibodies-producing clones were also obtained by the hybridoma technique. The specificity of monoclonal antibodies against GAD were established from the following criteria: positive on ELISA test using homogeneous GAD as antigen; formation of GAD--anti-GAD IgG complex as indicated from gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis; and specific recognition of GAD subunit in a partially purified GAD preparation in Western immunoblotting test. Monoclonal antibodies were further characterized by immunohistochemical localization of known GABAergic neurons and their processes in the cerebellum and retina.

Animals↗
PubMed1986

Modulation of tissue mononuclear phagocyte clonal growth by oxygen and antioxidant enzymes.

We have investigated the effects both of oxygen concentrations below that of ambient air in the gas phase and antioxidant enzymes on the clonal growth of various tissue mononuclear phagocyte colony-forming cells in vitro. The degree of enhancement in growth is dependent on the source of these colony-forming cells. Clonal growth of colony-forming cells from peritoneal exudate was enhanced both by lowering the oxygen tension and using three antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase). The optimal concentration of oxygen was 6%. Colony-forming cells from alveolar spaces failed to respond to either the reduction in oxygen tension or the addition of antioxidant enzymes to the culture dishes. The optimal concentration of oxygen for the clonal growth of blood monocytes was 6%. However, clonal growth was enhanced more in soft agar than in liquid culture. Our data also suggest that at least part of the growth-enhancing effect of hemolysate may be attributable to its ability to decrease oxygen toxicity.

Animals↗
PubMed1985

Biosynthesis of prostaglandins and hydroxy fatty acids in primary squamous carcinomas of head and neck in humans.

The metabolism of [14C]arachidonic acid into cyclooxygenase and lipoxygenase products by homogenates of primary squamous carcinomas of head and neck in 12 patients was studied in vitro. The lipoxygenase pathway was predominant in all samples. The major metabolites were 12-hydroxy-5,8,11-14-eicosatetraenoic acid, (12-HETE) and 15-HETE. 5-HETE, 5,12-diHETE, 8-HETE and 9-HETE were also detected. The cyclooxygenase products detected were in the following order: PGE2 greater than PGF2 alpha greater than TxB2 greater than 15-keto-PGE2 greater than 6-keto-PGF1 alpha greater than PGD2. Literature review of the biological activities of these oxygenated metabolites of arachidonic acid suggest important modulatory roles in the pathophysiology of head and neck cancer.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1985

Isolation and purification of an endogenous brain ligand for benzodiazepine receptor(s).

An endogenous brain ligand which competes with 3H-flunitrazepine for the binding to benzodiazepine receptor has been isolated and purified to homogeneity. The purification procedures involve the liberation of the ligand into the high speed supernatant followed by ultrafiltration through a PM10 membrane (exclusion limit: 10,000-dalton) column chromatographies on Sephadex G-50, Bio-Rad P2 and finally with three times reversed phase HPLC using C18 columns. The purified endogenous ligand is heat stable, insensitive to DNAase or RNAase and contains about 5-10% amino acid residues. It has an absorption maximum at 220 nm and a minor peak at 313 nm. The exact chemical structure is unknown.

Animals↗
PubMed1985

Effects of dose rate and dose fractionation of irradiation on pulmonary alveolar macrophage colony-forming cells.

We have studied the effects of dose rate and dose fractionation on murine pulmonary alveolar macrophage colony-forming cells (AL-CFC). The dose-response curve of AL-CFC to ionizing irradiation has a Dq of about 100 rad, reflecting the cells' ability to repair sublethal damage. For comparison, we investigated the effect of dose schedule on the committed bone marrow stem cells for both granulocytes and monocytes (GM-CFC) since their dose-response curve has a very small shoulder. We compared the results of dose rates of 3 and 10 rad/min to those obtained with a dose rate of 85 rad/min. We determined survival after giving 100, 300, and 500 rad either in vivo or in vitro. A significant dose rate effect was observed. To study the effect of dose fractionation, a total of 600 rad was given either as a single fraction, three fractions of 200 rad on 3 consecutive days, or six fractions of 100 rad in 3 days. The most dramatic effect was seen in the group that received six 100-rad fractions. No reduction in the number of AL-CFC was seen in this group. In sharp contrast, only a minimal dose schedule effect was observed with GM-CFC.

Animals↗