Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human monocyte-like cell line, U-937, is known to differentiate into macrophage-like cells following stimulation with phorbol myristate acetate (PMA) or interferon-gamma (IFN-gamma). The activated cells have been reported to have enhanced capacity to synthesize C2, C3, Factors B and H. Here, U-937 cells were used as a model system to investigate the effects of immunomodulatory agents on the biosynthesis of Factor P by monocytoid cells. Non-stimulated U-937 cells progressively secreted increasing amounts of Factor P over a 72-hr culture period. The secreted Factor P was hemolytically active. The daily production of Factor P was nearly linear (approx. 2.1 +/- 0.2 ng/10(6) cells; mean +/- SEM). Factor P synthesis was reversibly inhibited by cycloheximide indicating de novo synthesis. Both secreted Factor P and Factor P in normal plasma contained Factor P of heterogeneous molecular sizes and eluted from Sephacryl S-300 gel filtration column as a broad peak (mol. wt 250-800 kDa). The synthesis of Factor P by U-937 cells was augmented 1.8-, 2.1- and 2.5-fold respectively following induction with PMA (30 ng/ml), IFN-gamma (100 U/ml) and LPS (0.1 microgram/ml). Metabolic labeling of U-937 cells and autoradiograms of SDS-PAGE analysis of Factor P immunoprecipitates demonstrated a 54 kDa band in the culture supernate, co-migrating with purified 125I Factor P. Intracellular Factor P however had an apparent mol. wt that was 4000 kDa smaller than secreted Factor P. Thus U-937 cells synthesize a precursor Factor P subunit polypeptide chain which undergoes post-synthetic glycosylation and polymerization to give rise to the oligomers characteristic of native Factor P in fresh plasma. Our data also demonstrate that Factor P synthesis by monocytic cells can be enhanced by immunomodulatory factors or mediators that are generally found at sites of inflammation and immune response.
Mol Immunol 1988 Dec
PMID:Biosynthesis of complement factor P (properdin) by the human pre-monocyte cell line (U-937). 323 19

Freeze-fracture methods were used to study the sarcoplasmic reticulum and surface membranes in muscles from rats after chronic administration of triiodothyronine (150 micrograms/kg daily, for 1 to 20 days). The major effect of the hormone on the sarcoplasmic reticulum was to increase the numbers of indentations in the terminal cisternae in parallel with an increase in the speed of the isometric twitch. The indentations increased from 7.3 +/- 0.2 to 10.6 +/- 0.1 (mean +/- 1 SEM)/micron of terminal cisternae in the fast-twitch extensor digitorum longus (EDL) and from 0.9 +/- 0.1 to 4.4 +/- 0.1/micron in slow-twitch soleus fibers. The increase in indentation density in both types of muscle occurred within 10 days of the commencement of hormone injection. During the same period there was a small reduction in the density of intramembrane particles in the plasmalemma and a significant increase in the number of caveolae, from 14.6 +/- 0.25 to 20.4 +/- 0.3/micron2 in EDL fibers, and from 22.9 +/- 0.3 to 28.6 +/- 0.3/micron2 in soleus. The increase in caveolae density was coincident with an increase in the area of T-tubule membrane. The results provide further evidence that the indentations in the terminal cisternae play a functional role in muscle activation and that the caveolae are the surface openings of transverse tubules.
J Ultrastruct Mol Struct Res 1986 Feb
PMID:A freeze-fracture study of extensor digitorum longus and soleus muscle fibers from thyrotoxic rats. 378 25

Calmodulin levels were measured by radioimmuno-assay in freshly isolated and cultured psoriatic human scalp hair follicle cells. The mean value +/- SEM for calmodulin was 1.97 +/- 0.15 ng calmodulin micrograms-1 protein for 16 control subjects whereas calmodulin levels were significantly increased in psoriatic hair follicles, 2.93 +/- 0.26 ng calmodulin micrograms-1 protein (uninvolved skin) for 18 patients and 3.09 +/- 0.21 ng calmodulin micrograms-1 protein for involved skin derived hair follicles for 17 of these patients. In vitro, 3-week-old cultures of psoriatic keratinocytes contained less DNA and more calmodulin per DNA than their normal counterparts. When 6 week-old cultures of psoriatic and control hair follicle keratinocytes were compared, this difference disappeared. These results are related to the state of differentiation of these cultures.
Mol Biol Rep 1986
PMID:Psoriatic hair follicle cells. IV. Calmodulin levels in freshly isolated and cultured human scalp hair follicle cells. 380 3

The osmotic behavior of control lymphocytes (CL) and polymorphonuclears (CPMN) was compared with that of cells from patients with chronic lymphocytic leukemia (CLL) and chronic myelocytic leukemia (CML), using the method of gradual dialysis against distilled water. The results were evaluated with a fragiligraph, and by scanning (SEM) and transmission (TEM) electron microscopy. The fragiligraphy curves showed that CLL cells are more resistant to osmotic pressure than the CL, whereas the curves for CPMN and CML cells showed an overlap. Surface alterations in CL appeared as early as 1 min of dialysis, while in CLL cells the membrane did not show major alterations even after 5 min of dialysis. CPMN also showed alterations earlier than CML cells, but this difference was not as prominent as in the case of lymphocytes and was observed for a maximum of 3 min of dialysis. The internal structure of the cells was altered earlier than the surface membrane and this was expressed mainly in the nucleus in both control and leukemic cells. Also in this respect, the internal structure of CL was altered earlier than that of CLL cells, whereas no major differences were observed between CPMN and CML cells.
Virchows Arch B Cell Pathol Incl Mol Pathol 1982
PMID:SEM and TEM studies on the osmotic behavior of control and leukemic lymphocytes and polymorphonuclears. 612 53

Isolated rat hepatocytes in early primary culture were incubated in the presence of three substituted nitroimidazoles currently of clinical interest as tumour radiosensitisers. The effects of 3h treatments with Misonidazole (MISO), Desmethylmisonidazole (DESMISO) and the basic compound Ro 03-8799 were monitored both directly from treatment and following a 24h 'recovery' period. Morphological changes were observed by SEM and TEM and included effects on the plasma membrane and the nucleus. The plasma membrane of DESMISO and 03-8799 treated cells was characterised by blebbed regions not present in control cultures, and considered indicative of an early toxic insult. Blebs were most evident in 03-8799 treated hepatocytes where they often contained coils of endoplasmic reticulum within the ground plasma. Blebbed areas were less evident 24h after the removal of the drugs from surviving cells. An increased aggregation of peripherally located heterochromatin within the nucleus was the other main morphological alteration induced by nitroimidazole treatment. This was again more prevalent in 03-8799 and DESMISO exposures; and particularly in cells demonstrating membrane damage. Parallel viability studies indicated an efficacy of the nitroimidazole towards rat liver parenchymal cells in primary culture of Ro 03-8799 greater than DESMISO greater than MISO. This fitted the order predicted from the morphological findings and from previously published clinical data. The validity of monitoring structural parameters as a means of initially indicating lesion sites following drug treatments in the hepatocyte cytotoxic screening model is considered.
Virchows Arch B Cell Pathol Incl Mol Pathol 1984
PMID:Morphological changes in rat hepatocytes in primary culture induced by Misonidazole, desmethylmisonidazole and Ro 03-8799. 614 29

A microradioimmunoassay for cAMP was developed in order to analyse the effects of alpha-adrenergic agonists on vasopressin (AVP)-induced cAMP cell accumulation in single pieces of microdissected medullary (MCT) and cortical (CCT) rat collecting tubules. Under the experimental conditions chosen (4 min of incubation in the presence of a phosphodiesterase inhibitor), no cAMP could be detected either in the bathing solution or in non-stimulating samples of tubule. In MCT, 10(-6) M AVP stimulated cAMP generation up to 128.3 +/- 9.0 (SEM) fmoles per mm of tubule per 4 min, N = 11. The response was dose-dependent with a KA value below 10(-10) M AVP. The addition of norepinephrine (NE) (10(-5) M in the presence of propranolol) suppressed the larger part of the response to AVP (from 92% with 2 X 10(-11) M AVP to 76% with 10(-6) M AVP); the addition of 10(-7) M NE still reduced by 59% the MCT response to 10(-10) M AVP (26.2 +/- 5.9 vs. 64.0 +/- 6.4 fmoles/mm, N = 3). In CCT, 10(-5) M NE reduced by 84% the cAMP generation induced by 10(-10) M AVP (8.8 +/- 2.0 vs. 54.2 +/- 3.5 fmoles/mm, N = 3). This inhibitory action of NE against the AVP effect in CCT was mimicked by 10(-7) M clonidine; in MCT it was suppressed by phentolamine and yohimbine, but not by prazosin, suggesting that alpha 2-adrenoreceptors are involved. On the other hand, the addition of the alpha-agonists to the incubation solution produced no inhibition of the cAMP cell accumulations induced by glucagon, calcitonin and isoproterenol in CCT, or glucagon in MCT, an observation demonstrating that alpha 2-adrenergic agonists selectively inhibit vasopressin-dependent cAMP generation by these nephron segments.
Mol Cell Endocrinol 1984 Oct
PMID:Inhibition of alpha 2-adrenergic agonists on AVP-induced cAMP accumulation in isolated collecting tubule of the rat kidney. 614 67

The concentration of thyroid hormone nuclear receptors varies from one tissue to another, the anterior pituitary (AP) gland possessing the highest. Since 3,5,3',1-triiodothyronine (T3) controls within a narrow range the secretion of TSH from the pituitary gland, this study was carried out to establish whether T3 modulates its own pituitary nuclear receptors and if so, whether this modulation is correlated with the thyroidal status and TSH secretion. Salt-solubilized T3 nuclear receptors were measured in the AP gland of thyroidectomized and intact adult male rats as well as in thyroidectomized rats treated with T3. In intact male rats the maximum binding capacity of pituitary T3 nuclear receptors (MBC-T3nR), determined by Scatchard analysis, was 578 +/- 45 fmoles T3/mg protein or 27 +/- 3 fmoles T3/AP (mean +/- SEM, n = 19). 2 weeks after thyroidectomy there was a marked decrease in serum T3 and T4 concentrations as well as in the MBC-T3nR (231 +/- 26 fmoles T3/mg protein or 9.3 +/- 1.2 fmoles T3/AP, n = 7) which was still observed 8 and 16 weeks after thyroidectomy. The affinity constant (Ka) of T3 for its pituitary nuclear receptors was significantly greater in thyroidectomized rats than in intact rats (3.61 +/- 0.70 vs. 1.09 +/- 0.15 X 10(10) M-1, P less than 0.001). To test whether treatment with T3 would restore a normal MBC-T3nR, 2-week thyroidectomized rats were injected with T3(0.5 micrograms/100 g b.w.) and killed 10 min, 1, 3, 15 or 24 h after T3 injection. 10 min after T3 injection MBC-T3nR was not altered but it returned to normal values 1 h after injection (441 +/- 97 fmoles T3/mg protein) and was maintained so for at least 3 h. 15 h after T3 injection MBC-T3nR was again decreased in spite of serum T3 levels that were twice as high as in normal rats. In contrast, when T3 was injected at the dose of 1.0 micrograms/100 g b.w. the MBC-T3nR was maintained within the normal range as long as 24 h after the injection (428 +/- 125 fmoles T3/mg protein) with serum T3 concentrations that were twice the normal levels (1.27 +/- 0.06 vs. 0.67 +/- 0.01 ng/ml). These results support the hypothesis that T3 modulates the concentration of its own nuclear receptors in the rat pituitary gland. The absence of any effect of T3 10 min after injection is suggestive of an effect of T3 on the synthesis of its receptors rather than on an alteration of unoccupied receptors that would require T3 for adequate configuration and detection. This modulation of pituitary T3 receptors by T3 may provide an additional mechanism of regulation of TSH secretion in thyroid insufficiency.
Mol Cell Endocrinol 1983 Dec
PMID:Modulation of thyroid hormone nuclear receptor levels by L-triiodothyronine (T3) in the rat pituitary. 631 85

[125I]hCG binding to thecal tissue from healthy bovine follicles was examined and compared to [125I]hCG binding to other bovine ovarian tissues. [125I]hCG bound specifically to theca interna but not to theca externa. Binding to theca interna was a time- and temperature-dependent process, the rate of association obeying second-order kinetics with calculated rate constants of 1.97 +/- 0.13 X 10(5) and 0.85 +/- 0.04 X 10(5) 1 M-1 sec-1 at 37 and 22 degrees C, respectively. The dissociation of [125I]hCG from theca interna was a slow biphasic process with only 40% of specifically bound [125I]hCG being liberated after 8 h at 37 degrees C. Unlabelled hCG and LH, but not FSH, prolactin, GH, TSH or GnRH, inhibited [125I]hCG binding to theca interna. The specific binding of [125I]hCG to theca interna was saturable and equilibrium binding data produced a linear plot when fitted to the Woolf equation. The equilibrium dissociation constant (Kd) and maximum binding capacity (Bmax) calculated from Woolf plots were 0.21 +/- 0.02 nM (mean +/- SEM) and 34 +/- 4 fmoles/mg protein, respectively. Constants for [125I]hCG binding to granulosa cells and luteal tissue, respectively, were 0.29 +/- 0.02 and 0.31 +/- 0.04 nM for the Kd values and 32 +/- 6 and 116 +/- 13 fmoles/mg protein for the Bmax values. [125I]hCG binding constants for small (less than 8 mm dia.) and large (greater than or equal to 8 mm dia.) follicles (healthy or atretic) were not significantly different. In addition, there was no difference in the [125I]hCG binding constants of healthy and atretic follicles (large or small).(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Endocrinol 1984 Feb
PMID:[125I]hCG binding to bovine thecal tissue from healthy and atretic antral follicles. 632 71

Adipocytes from old rats (greater than 450 g) were separated into 2 populations with mean cell volumes of 201 +/- 14 and 813 +/- 41 pl (mean +/- SEM, 20 observations) by filtering through nylon mesh (64 microns diameter) and compared with adipocytes from young rats (less than 150 g) with a mean adipocyte volume of 154 +/- 20 pl (14 observations). Large adipocytes had more insulin receptors per cell but less per unit of surface area. They internalized greater amounts of insulin than small cells in the presence or absence of bacitracin and chloroquine, although the proportion of bound hormone which was internalized was similar in all 3 groups. Down-regulation of the insulin receptor was evident in large and small adipocytes after incubation in the presence of 10(-7)M insulin. Large cells degraded insulin (extracellularly and intracellularly) at significantly greater rates than small cells whether expressed per cell or per unit of surface area. Small cells from old rats had essentially identical properties to small cells from young rats in all parameters examined. The results suggest that the decreased surface density of insulin receptors observed in large adipocytes from old rats is due to size rather than age and that the decreased insulin sensitivity of large adipocytes is not due to an inability to internalize insulin or down-regulate its receptors but may be due to increased rates of insulin degradation.
Mol Cell Endocrinol 1984 Jul
PMID:Effects of cell volume on insulin binding, internalization and degradation in rat adipocytes. 638 Nov 72

Monoclonal antibodies generated against normal and leukemic human leukocytes were tested for their differential reactivity with leukemia and lymphoma cell lines as well as with circulating lymphoid and myeloid leukemic cells by means of immuno-scanning electron microscopy (immuno-SEM). Anti-T (OKT3), anti-mu-chain, anti-CALLA (J5), anti-BA-1, anti-BA-2, and anti-nonlymphoid (Mol) monoclonal antibodies were covalently conjugated to polystyrene latex microspheres (immunolatex), using a two-step glutaraldehyde reaction, and subsequently incubated with the various cell types. Cultured B-type Burkitt lymphoma cells (Daudi) and chronic lymphocytic leukemia (CLL) cells displayed extensive labeling with monoclonal anti-mu, anti-B1, and anti-BA-1 immunolatex conjugates, while cultured malignant T cells (HD-Mar) showed positive labeling with OKT3 immunolatex alone. Cultured myelomonocytic cells (GDM-1) and cells obtained from patients with acute myeloblastic (AML) and monoblastic leukemia (AMoL) labeled only with anti-Mol immunolatex, while cultured promyelocytic cells (HL-60) displayed far less labeling with this conjugate. Common-type acute lymphoblastic leukemia (C/ALL) cells were labeled predominantly with the J5 (anti-CALLA) and anti-BA-2 immunolatex conjugates. Evidence is presented indicating that immuno-SEM employing monoclonal antibodies is a reproducible technique which may be used in the study of leukocyte maturation and may provide additional information in the classification of poorly differentiated leukemias.
 ...
PMID:Utilization of monoclonal antibodies and immuno-scanning electron microscopy for the positive identification of human leukemic cells. 658 Nov 72


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