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C F Zukoski

Publications and source records attributed to C F Zukoski.

At least 37 records · Page 2Linked to original sources
PubMed1990

Identification of prolactin-like proteins synthesized by normal murine lymphocytes.

Cultured murine lymphoid cells release a PRL-like immunoreactive (IR) protein which may be important in immunity, as anti-PRL antisera inhibit lymphocyte proliferation in vitro. We examined culture supernatants (SNs) and cell lysates from concanavalin A (Con A) activated murine thymocytes to identify these proteins. Western blot analysis of cell lysates revealed three specifically-stained PRL-IRs. A doublet of bands at 35.6 and 33.6 kDa was associated with the particulate fraction of the cell. These PRL-IRs were present in lymphocytes independently of mitogen stimulation. In contrast, a 22 kDa PRL-IR was only produced in mitogen stimulated cells, and was specifically immunoprecipitated with anti-PRL antiserum. In addition, all three PRL-like IRs incorporated 35S-methionine in vitro, indicating that they are synthesized by these cells. Only the 22 kDa PRL-like protein was present in culture medium from stimulated cells, suggesting that this may be the PRL bioactivity previously demonstrated in SNs from murine lymphocytes.

Animals↗
PubMed1987

Concanavalin A-stimulated murine splenocytes produce a factor with prolactin-like bioactivity and immunoreactivity.

Culture supernatants from concanavalin A activated murine splenic mononuclear cells (splenocytes) were assayed for prolactin-like molecules using the Nb2 node lymphoma bioassay and immunostaining procedures. Con A stimulated splenocytes produced a factor with prolactin-like immunoreactivity that was mitogenic for Nb2 lymphoma cells. This factor first appeared in culture supernatants with the onset of lymphocyte mitogenesis and its activity was proportional to the number of cells cultured. In addition, splenocyte proliferation was inhibited by antiserum to rat prolactin, and this inhibition was partially reversed by added hormone. These findings show that murine splenocytes produce a substance with prolactin-like activity and suggest that this factor is essential for lymphocyte proliferation.

Animals↗
PubMed1987

Prolactin-dependent mitogenesis in Nb 2 node lymphoma cells: effects of immunosuppressive cyclopeptides.

Prolactin (PRL)-stimulated ornithine decarboxylase (ODC) activity and subsequent proliferation are inhibited by the cyclopeptides cyclosporine (CsA) and didemnin B (DB) in Nb 2 node lymphoma cells. Similar concentrations of these agents also inhibit 125I-PRL binding, suggesting that their inhibitory effects on these PRL-dependent physiologic responses are mediated at least in part at the level of PRL receptor interactions. The phorbol ester TPA stimulated ODC activity and [3H]thymidine incorporation to 54% and 31% that of a near-optimal mitogenic concentration of PRL (10 ng/ml), suggesting that mitogenesis in these cells is coupled to some degree to the activation of protein kinase C (PKC). The calcium ionophore A23187 increased ODC activity only slightly and actually decreased [3H]thymidine incorporation to a value below the "cells only" controls. The addition of TPA plus A23187 did not further enhance the effects of TPA to elevate ODC activity and [3H]thymidine incorporation. However, A23187 significantly elevated PRL-stimulated ODC activity with a subsequent inhibition of [3H]thymidine incorporation, suggesting a block of entry into S phase. Both cyclopeptides decreased the elevation of ODC activity in G1 phase of cell cycle in response to PRL, suggestive of a site of action for these agents in early G1, a conclusion compatible with their ability to inhibit PRL binding to these cells. Addition of CsA or DB 2 hr after PRL had no effect on PRL-stimulated ODC activity detectable at 6 hr, but addition of either as late as 6 hr still affected the extent of mitogenesis. This is in line with the requirement for PRL to be present in the culture medium for a minimum of 3 to 6 hr to invoke a maximal effect on mitogenesis. Addition of either cyclopeptide after the cells were in S phase had no effect on the extent of [3H]thymidine incorporation. An inhibitor of the cyclooxygenase pathway (indomethacin) enhanced both PRL-stimulated ODC activity and proliferation, whereas inhibition of the lipoxygenase pathway by NDGA attenuated only proliferation, suggesting that in Nb 2 cells, products of the lipoxygenase pathway may contribute to the mechanism of PRL-stimulated mitogenesis. Because Nb 2 lymphoma cells were derived from estrogenized rats, estrogen was tested as a mitogen. By itself it was not mitogenic, but in conjunction with PRL, estradiol-17 beta elevated the ODC response and inhibited proliferation. Inhibitors of PKC known to have minimal effects on RNA synthesis, quercetin and gossypol, totally inhibited both the elevations of ODC activity and [3H]thymidine incorporation in response to PRL in Nb 2 lymphoma cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Didemnin B--an immunosuppressive cyclic peptide that stimulates murine hemagglutinating antibody responses and induces leukocytosis in vivo.

Didemnin B (DB) is a cyclic peptide with potent immunosuppressive activity in vitro and in the murine graft-versus-host-reaction (GVHR), the only measure of in vivo immunity tested in our prior studies. Because continued production of mature leukocytes by bone marrow and an intact antibody response are crucial to defense against infection in immunosuppressed patients, we have evaluated the effects of DB on these processes as well. Anti-sheep red blood cell (SRBC) hemagglutinating antibody (hAb) production was induced by i.p. injection of 5 x 10(7) SRBC in CB6F1 mice (5/group) treated with vehicle or DB once/day for six days. Serum was collected on day 7 and hAb titers measured by SRBC agglutination. Control antibody titers were 1/16, while animals receiving DB doses of 0.025, 0.05, 0.10, and 0.20 mg/kg/day yielded titers of 1/37, 1/74, 1/56, and 1/74, respectively. This stimulation of hAb production (4.6 x control) was confirmed by a second experiment. We then studied DB effects (0.1 mg/kg/day x 6 days) on serum hAb titers in separate groups of five mice at 7, 10, 15, and 20 days postimmunization. Control hAb titers were 1/110 on day 7, then dropped to 1/60 on days 10, 15, and 20. DB-treated animals had titers of 1/130 on day 7, and 1/170 on days 10-20. These data show that DB treatment in vivo causes a persisting increase in anti-SRBC hAb titers. Evaluation of DB effects on proliferation and antibody secretion in vitro by three hybridoma cell lines showed a potent inhibition of cell replication but stimulation of antibody production on a per-cell basis in each clone (+26%-+900%, range), suggesting a direct effect on Ig synthesis. During our first in vivo DB studies (0.1 mg/kg/day x 7 days) in mice, we noted that peripheral blood white counts were elevated on day 8 to 21.3 +/- 2.1 x 10(3)/mm3 compared with control (vehicle only) levels of 13.6 +/- 2.0 x 10(3)/mm3 (P less than .01). Kinetic studies showed that by 24 hr after a single i.p. injection of DB (1.0 mg/kg), blood leukocyte, granulocyte, and lymphocyte counts were elevated by 2.5-, 3-, and 2-fold, respectively, but declined rapidly thereafter. 3H-thymidine incorporation (4 hr) by freshly harvested bone marrow leukocytes from DB-treated mice (0.025, 0.05, and 0.10 mg/kg/day x 7 days) was enhanced up to 40% over control (P less than .05), while bone marrow cellularity was increased 200% (P less than .01).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Prolactin stimulation of ornithine decarboxylase and mitogenesis in Nb2 node lymphoma cells: the role of protein kinase C and calcium mobilization.

The tumor promotor 12-O-tetradecanoylphorbol-13-acetate (TPA) in combination with calcium ionophores has been shown to bypass the requisite antigen- or lectin-induced signal for lymphocyte mitogenesis. This suggests that protein kinase C activation and calcium mobilization may be early events required for lymphocyte proliferation. Therefore, the relationship(s) of protein kinase C activation and calcium mobilization to ornithine decarboxylase induction and cellular proliferation were examined in a rat node lymphoma cell line (Nb2) which is dependent upon prolactin (PRL) for mitogenesis. TPA enhanced PRL-stimulated Nb2 node lymphoma cell ornithine decarboxylase induction and [3H]thymidine incorporation. Addition of a calcium ionophore (A23187) to cultures containing TPA plus PRL increased ornithine decarboxylase above PRL alone or PRL plus TPA but inhibited proliferation compared to the PRL plus TPA regimen. Exposure of cells to TPA or TPA plus A23187 increased [3H]thymidine incorporation in a similar manner to that demonstrated for low-dose PRL. However, optimal concentrations were only 20-25% as effective as mitogens as was optimal PRL. Protein kinase C and calmodulin antagonists inhibited PRL-stimulated ornithine decarboxylase induction and proliferation. Ca2+ chelation or cation channel antagonism inhibited both PRL-stimulated responses. The cyclic AMP analogue, 8Br-cAMP, inhibited PRL-stimulated ornithine decarboxylase activity as well as cellular proliferation processes assessed by [3H]thymidine incorporation. Finally, tumor-promoting phorbol esters inhibited 125I-rPRL binding. These data strongly suggest that protein kinase C activation and calcium mobilization are requisite events for PRL-stimulated ornithine decarboxylase induction and cellular proliferation in Nb2 node lymphoma cells. An additional component that is linked to alterations in K+ channeling is also implicated. These data support a role for protein kinase C in PRL-coupled mitogenesis. However, other critical Ca2+ and/or ion-induced events are also required.

Animals↗
PubMed1985

Dynamic organ culture of precision liver slices for in vitro toxicology.

The lack of a reproducible method for the production of thin tissue slices has hindered the use of liver slices as an in vitro tool for hepatotoxicity studies. Fresh human, rat, and rabbit liver was processed using a mechanical slicer. With this instrument, precision (5% of thickness) liver slices in the submillimeter range could be produced at a rapid rate. Slices were prepared from fresh livers in chilled, oxygenated buffer to minimize trauma. Following incubation for up to 20 h in a dynamic organ culture system, histology of incubated slices suggested that 250 m precision-cut slices were optimum in regard to morphology relative to liver slices incubated under conventional organ culture conditions. Addition of bromobenzene to the culture showed time-dependent hepatotoxicity based on two classic parameters of cell degeneration. Histological evidence is presented which suggests the usefulness of this system for hepatotoxicity studies and the production of focal necrosis in vitro.

Animals↗
PubMed1985

Didemnin B: a new immunosuppressive cyclic peptide with potent activity in vitro and in vivo.

Didemnin B (DB) is a 7-amino-acid, cyclic polypeptide with potent (10(7)-10(10)M) antiproliferative effects in vivo and in vitro against a variety of viruses and tumor cell lines. Because lymphocyte blastogenesis is essential for many immune responses, DB appeared likely to exert immunosuppressive effects as well. Using primary cultures of murine (Balb/c) splenic mononuclear cells to evaluate this possibility, we found that DB was a potent (IC50 = 190 ng/ml) inhibitor of lymphocyte protein synthesis, although RNA synthesis and cell viability were unaffected. However, it markedly inhibited blastogenesis stimulated by concanavalin A (IC50 = 50 pg/ml), lipopolysaccharide (IC50 = less than 100 pg/ml) and alloantigen (IC50 = less than 10 pg/ml) when added to cultures immediately after stimulation. DB added later, at the time of thymidine labeling was much less potent (1/46-1/1430), suggesting that the lymphocyte activation process is particularly sensitive to this agent. Our finding that alloantigen-driven proliferation was exquisitely sensitive to DB (greater than 90% inhibition at 10 pg/ml) led us to test its effects in vivo using the Simonsen parental-to-F1 graft-versus-host reaction (GVHR). Treatment of graft recipients with 0.05, 0.10, and 0.20 mg DB/kg/day for 7 days produced 51%, 40%, and 60% inhibition of splenomegaly induced by the GVHR, and treatment with 0.3 mg/kg/day on days 1, 2, 4, and 6 inhibited 71%. These data show that the in vitro inhibition of alloantigen-driven blastogenesis by DB was reproduced by in vivo treatment as well, even across major histocompatibility differences. This leads us to conclude that DB has potent immunosuppressive activity both in vitro and in vivo.

Animals↗
PubMed1983

A rational approach to serious blunt hepatic injury.

Based on our cumulative experience in patients with serious blunt liver trauma, hepatic resection is seldom necessary where cross-clamping the hepatoduodenal ligament (portal triad) effectively stops parenchymal hemorrhage. Oversewing or "hemo-clipping" of intrahepatic disrupted vascular tributaries combined, when appropriate, with lobar hepatic arterial ligation and transposition of an omental pedicle graft into the "fracture" defect is usually sufficient treatment. On the other hand, avulsion of hepatic veins and/or tears of the retrohepatic vena cava require major hepatic resection primarily for exposure. But even in conjunction with internal vena caval bypass shunts, the mortality with this injury remains high.

Adolescent↗
PubMed1982

The potential impact of digital video subtraction angiography on screening for renovascular hypertension.

The success of digital video subtraction angiography (DVSA) in screening hypertensive patients for renal artery stenosis and the apparent value of percutaneous transluminal angioplasty (PTA) prompted re-evaluation of the philosophy of indiscriminate medical therapy for newly discovered cases of hypertension. DVSA was diagnostic in 87% of cases. The cost of screening for renovascular hypertension by DVSA and treatment by PTA when feasible is about the same as that of medical therapy. Considering the problems of noncompliance and drug side effects associated with medical antihypertensive therapy, DVSA screening for renovascular hypertension in a broader population seems both medically and economically sound.

Angiography↗
PubMed1982

Evaluation of potential renal donors and renal allograft recipients: digital video subtraction angiography.

Digital video subtraction angiography is a safe, easily performed, outpatient procedure that was applied to evaluating the arterial anatomy of 11 potential renal donors and 22 examinations of 19 renal allograft recipients. Digital intravenous angiography depicted the number and position of renal arteries preoperatively in renal donors and excluded renal arterial or parenchymal disease. It accurately defined transplant arterial stenoses and demonstrated the status of the intrarenal circulation. No morbidity nor decreased renal function resulted. Digital video subtraction angiography has become the procedure of choice for these referrals at this institution.

Adult↗
PubMed1980

Red cell electrophoretic mobility test for early diagnosis of multiple sclerosis.

We have confirmed the red cell electrophoretic mobility-unsaturated fatty acid test for multiple sclerosis, which involves measuring the change in electrophoretic mobility of erythrocytes in Medium 199 upon the addition of linoleic acid. Using defibrinated blood samples, the average decrease in the mobility of red cells upon the addition of linoleic acid of 57 multiple sclerosis patients was 6.7 +/- 2.1% and that of 23 normal control subjects was .09 +/- 1.2% (p less than 0.001). In addition, blood anticoagulated with trisodium citrate was found to give similar test results, and such preparations were found to be simpler and quicker to use.

Electrophoresis↗
PubMed1980

The physical and functional heterogeneity of circulating lymphocyte populations.

There is a considerable heterogeneity amongst populations of both fixed and circulating lymphocytes other than that determined by the organs from which these cells originate. The functional differences with which these cells are endowed during their primary differentiation are further modified by the changing environments they encounter during their life and by reassortitive processes occurring during their migration. The range of inductive and modulating stimuli applied to the free-floating and fixed lymphoid cell populations in different parts of the lymphatic apparatus is changing continually and this leads to patterns of cell differentiation which persist for variable periods of time. The experience of a variety of environmental interactions gives the lymphocyte a range of reactive options which are denied to those cells held in fixed relationships with other cells. As a consquence there is no predictable equivalence in the morphological or functional attributes of different lymphocyte populations present in different parts of the lymphatic system.

Animals↗