Lipid peroxidation assessment of free radical production following release of obstructive uropathy

PURPOSE

To identify if free radicals were released following relief of ureteric obstruction.

MATERIALS AND METHODS

Free radical production was assessed by a high performance liquid chromatography assay of malondialdehyde (MDA) in a 24-hour complete unilateral ureteric obstruction model in Wistar rats.

RESULTS

In the first experiment, a rise greater than 20% above prerelease levels in renal venous malondialdehyde levels was observed at 8, 15, 22, and 30 minutes following release. At 45 and 60 minutes, levels were similar to the prerelease levels. In the second experiment, renal venous samples taken before release and at 10 and 20 minutes after release in control and obstructed groups (n = 7) identified a significant difference (T = 10 minutes p = 0.006 and T = 20 minutes p = 0.045). A significant MDA rise following release occurred only in the obstructed group (obstruction group; MDA level T = 0 min. 1.01 mumol/l. +/- 0.13, T = 10 min. 2.12 mumol/l. +/- 0.3 p = 0.016, T = 20 min. 2.09 mumol/l. +/- 0.28 p = 0.016.

CONTROL GROUP

T = 0 min. 1.13 mumol/l. +/- 0.23, T = 10 min. 1.05 mumol/l. +/- 0.18 p = 0.95, T = 20 min. 1.23 mumol/l. +/- 0.19 p = 0.67). In the third experiment, an attempt was made to block free radical release with allopurinol. No statistical difference between the control and obstructed groups with allopurinol was noted at 20 minutes after release. A Kruskal Wallace two-way analysis identified a significant difference between experiments two and three at both time periods (p = 0.049).

CONCLUSION

This study suggests, for the first time, that free radicals are released after relief of ureteric obstruction and that this release is partially attenuated by allopurinol pretreatment.

cDNA cloning and characterisation of a maize homologue of the MCM proteins required for the initiation of DNA replication

A central question in cell cycle regulation is how DNA replication is initiated and executed only once in each cell cycle. The cell cycle-regulated assembly of specific initiation protein complexes at chromosomal origins appears to specify the initial sites and timing of DNA replication, and to restrict this process to only one round in the somatic cell cycle. Among the enzymes involved in origin activation, the MCM proteins play a conserved key role. In particular, MCM3 homologues have been shown to be components of the DNA replication licensing activity in yeast and vertebrates. In spite of our detailed knowledge of the regulation of the initiation of DNA synthesis in yeast, there is virtually no information available on the molecules involved in origin activation in higher plants. We have isolated a cDNA from maize root apices, termed ROA (Replication Origin Activator), encoding a protein which shares a high degree of homology with the MCM3 subfamily of MCM proteins. Analysis of gene organisation by Southern blotting shows 2-4 copies per haploid genome of closely related ROA sequences and the presence of further less related sequences in a multigene family. The steady-state levels of ROA mRNA are under developmental control, being relatively high in proliferative tissues such as the root apex, the developing cob and the coleoptile, and are strongly correlated with that of the histone H4 transcript. In situ hybridisation analysis in the root apex reveals that ROA mRNA expression is limited to specific subpopulations of cycling cells, which is typical of cell cycle-regulated expression. The isolation of nearly identical sequences from barley and Arabidopsis by the polymerase chain reaction indicates that MCM-related proteins are conserved in higher plants.

Mechanisms of immune suppression in patients with head and neck cancer: influence on the immune infiltrate of the cancer

Freshly excised human head and neck cancers (219 primary cancers; 64 metastatic lymph node cancers) were analyzed for the immune inhibitory mediators released from the cancer tissues and the immune infiltrate within the tumor. Significant levels of the immune inhibitory mediators transforming growth factor-beta (TGF-beta), prostaglandin E2 (PGE2) and interleukin-10 (IL-10) were released from these cancers. Also released was granulocyte-macrophage colony-stimulating factor (GM-CSF), whose secretion was associated with an intratumoral presence of CD34+ cells. We have previously shown that CD34+ cells within human head and neck cancers are immune inhibitory granulocyte-macrophage progenitor cells. The presence of TGF-beta, PGE2 and IL-10 was associated with a reduced content of CD8+ T-cells within the cancers. The CD4+ cell content appeared to be less affected by these immune inhibitory mediators. Instead, parameters indicative of CD4+ cell function (p55 IL-2 receptor expression, release of IL-2 and IFN-gamma) were diminished in cancers that released higher levels of TGF-beta, IL-10 and GM-CSF and had a higher CD34+ cell content. Furthermore, metastatic cancers released higher levels of the soluble immune inhibitory mediators and lower levels of IFN-gamma and IL-2 than did primary cancers, although CD34+ cells were similarly present in both primary and metastatic cancers. Our results show that human head and neck cancers have a multiplicity of non-mutually exclusive mechanisms of immune suppression that are most prominently associated with reduced CD8+ cell influx and reduced influx and altered function of intratumoral CD4+ cells.

Vitamin D3 treatment of tumor bearers can stimulate immune competence and reduce tumor growth when treatment coincides with a heightened presence of natural suppressor cells

By secreting granulocyte-macrophage colony-stimulating factor (GM-CSF), Lewis lung carcinoma tumors induce immune suppressive granulocyte-macrophage progenitor cells. Treating mice having established tumors and high levels of suppressor activity with vitamin D3 eliminated suppressor activity, increased anti-tumor immunity, induced an immune stimulatory cell population, and reduced tumor growth. When instead, the vitamin D3 treatment was initiated earlier, when implanted tumors first became detectable and when natural suppressor activity was less prominent, the treatment had no effect. Thus, vitamin D3 treatment can stimulate the immune competence of tumor bearers when treatment is targeted to coincide with a heightened presence of GM-CSF-induced suppressor cells.

Protein kinase A regulates Lewis lung carcinoma adherence to extracellular matrix components and spontaneous metastasis

Tumor cell adhesion to and migration through the extracellular matrix (ECM) can influence their capacity to disseminate. Since prior studies with Lewis lung carcinoma (LLC) tumors had shown metastatic clones to have more protein kinase A (PKA) activity than nonmetastatic clones, the present study assessed if PKA regulates the interaction between tumor and the ECM, and how this may be associated with the metastatic capacity of the tumor cells. This was accomplished with the use of metastatic (LLC-LN7) and nonmetastatic (LLC-C8) variants that had been stably transfected to overexpress the PKA Calpha subunit or to have blocked PKA activity. Cells with increased PKA activity were less adherent to vitronectin, laminin, and collagen I, and could more readily migrate through these ECM components than could transfectants with reduced PKA activity. PKA did not regulate adhesion to or migration through fibronectin, and did not appear to be associated with changes in expression of surface integrins. In addition to modulating tumor adhesion and migration in vitro, PKA activation caused an increased formation of metastases from s.c. tumors, but did not regulate formation of experimental metastases by i.v. injected tumor cells. These results suggest that PKA signaling is important for modulating the tumor-ECM interaction and can facilitate tumor transit from the primary tumor site.

Immune modulation by interleukin-12 in tumor-bearing mice receiving vitamin D3 treatments to block induction of immunosuppressive granulocyte/macrophage progenitor cells

Lewis lung carcinoma (LLC-LN7) tumors stimulate myelopoiesis and increase the presence of granulocyte/macrophage (GM) progenitor cells having natural suppressor activity. Treatment of these tumor-bearing mice with interleukin-12 (IL-12) resulted in minimal immune modulation. The objective of this study was to determine whether eliminating natural suppressor activity would allow for immune stimulation by IL-12. Treatment of LLC-LN7 tumor-bearing mice with vitamin D3 eliminated natural suppressor activity. In mice that were first treated with vitamin D3 and then also with IL-12, there was stimulation of splenic T cell proliferation in response to immobilized anti-CD3 plus IL-2. In addition, spleen and lymph node cells from vitamin-D3/IL-12-treated tumor-bearing mice became stimulated in response to autologous tumor to produce interferon gamma (IFN gamma), although IL-2 production was not stimulated. A prominent effect of the combined vitamin-D3/IL-12 treatment regimen was the synergistic augmentation of autologous tumor-specific cytolytic activity within the regional lymph nodes. The generation of these tumor-specific effector cells required the presence of the tumor mass since such activity was not elicited in the lymph nodes of mice from which the tumors had been surgically excised. The results of this study show that, after treatment of tumor bearers with vitamin D3 to eliminate GM-suppressor cells, IL-12 can induce select regional antitumor immune responses, particularly IFN gamma production and cytolysis by regional lymph node cells of autologous tumor.

Suppression of T cell proliferation by tumor-induced granulocyte-macrophage progenitor cells producing transforming growth factor-beta and nitric oxide

Production of high levels of granulocyte-macrophage CSF (GM-CSF) by LLC-LN7 tumors results in myelopoietic stimulation and an increase in cells having natural suppressor (NS) activity. Prior studies showed these NS cells could be isolated from the bone marrow of tumor-bearing mice with an Ab (ER-MP12) that recognized GM-progenitor cells. The present study showed these cells to also be in the spleen, lymph node, and tumor, and that treatment of tumor-bearing mice with low doses of IFN-gamma plus TNF-alpha reduced the frequency of E-MP12+ cells. Studies focused on characterizing the intratumoral ER-MP12+ cells and the mechanism by which they suppress T cell proliferation. When isolated and seeded in soft agar with CSF-containing LLC-LN7 supernatants, the ER-MP12+ cells grew into colonies, most of which contained both granulocytic and monocytic cells. Tumor-derived ER-MP12+ cells and their culture supernatants were suppressive to T cell proliferation. Among the factors produced by ER-MP12+ cells were TGF-beta, nitric oxide (NO), IL-10, and prostaglandin E2 (PGE2). However, it was TGF-beta and NO that mediated the suppression of T cell proliferation by ER-MP12+ cells. Intratumoral ER-MP12+ cells could be maintained as suppressive blastlike cells for at least 4 days in cultures containing CSFs, but adding IFN-gamma plus TNF-alpha to these cultures caused their differentiation mainly into nonsuppressive TNF-alpha-secreting monocytic cells. These results show that intratumoral ER-MP12+ cells having homology to GM-progenitor cells suppress T cell function by producing TGF-beta and NO. IFN-gamma/TNF-alpha treatment stimulates their differentiation and shift from production of TGF-beta and NO to production of TNF-alpha.

Suppression of T cell proliferation by tumor-induced granulocyte-macrophage progenitor cells producing transforming growth factor-beta and nitric oxide

Production of high levels of granulocyte-macrophage CSF (GM-CSF) by LLC-LN7 tumors results in myelopoietic stimulation and an increase in cells having natural suppressor (NS) activity. Prior studies showed these NS cells could be isolated from the bone marrow of tumor-bearing mice with an Ab (ER-MP12) that recognized GM-progenitor cells. The present study showed these cells to also be in the spleen, lymph node, and tumor, and that treatment of tumor-bearing mice with low doses of IFN-gamma plus TNF-alpha reduced the frequency of E-MP12+ cells. Studies focused on characterizing the intratumoral ER-MP12+ cells and the mechanism by which they suppress T cell proliferation. When isolated and seeded in soft agar with CSF-containing LLC-LN7 supernatants, the ER-MP12+ cells grew into colonies, most of which contained both granulocytic and monocytic cells. Tumor-derived ER-MP12+ cells and their culture supernatants were suppressive to T cell proliferation. Among the factors produced by ER-MP12+ cells were TGF-beta, nitric oxide (NO), IL-10, and prostaglandin E2 (PGE2). However, it was TGF-beta and NO that mediated the suppression of T cell proliferation by ER-MP12+ cells. Intratumoral ER-MP12+ cells could be maintained as suppressive blastlike cells for at least 4 days in cultures containing CSFs, but adding IFN-gamma plus TNF-alpha to these cultures caused their differentiation mainly into nonsuppressive TNF-alpha-secreting monocytic cells. These results show that intratumoral ER-MP12+ cells having homology to GM-progenitor cells suppress T cell function by producing TGF-beta and NO. IFN-gamma/TNF-alpha treatment stimulates their differentiation and shift from production of TGF-beta and NO to production of TNF-alpha.

Prostaglandin E2-protein kinase A signaling and protein phosphatases-1 and -2A regulate human head and neck squamous cell carcinoma motility, adherence, and cytoskeletal organization

Human head and neck squamous cell carcinoma (HNSCC) cultures were established from cancers of two patients. These cells were used to study if phosphorylation reactions by protein kinase A (PKA) and dephosphorylation reactions by protein phosphatases-1 and -2A (PP-1/2A) regulate tumor motility and adhesion to extracellular matrix components, and if this might be associated with cytoskeletal reorganization. Both cultures were motile and adherent to collagen I, fibronectin, vitronectin and laminin. Motility and adhesiveness was dependent on production of prostaglandin E2 PGE2 and on PKA activation. Blocking PP-1/2A activity with okadaic acid resulted in a PKA-dependent increase in m otility and, in some instances, adhesiveness by the HNSCC cells. The okadaic acid-induced increase in motility and adhesiveness coincided with a reduction in filamentous actin. These data suggest PKA and PP-1/2A have opposing effects in regulating the motility, adherence, and actin polymerization.

Bi-directional stimulation of adherence to extracellular matrix components by human head and neck squamous carcinoma cells and endothelial cells

Head and neck squamous cell carcinoma (HNSCC) cultures were established from two patients to determine if cancer and endothelial cells bi-directionally regulate their adherence to extracellular matrix components (ECM), an important process for tumor vascularization and metastasis. Soluble products from endothelial cells transiently enhanced adherence by HNSCC to ECM and increased surface levels of beta 1 and beta 4 integrins, although not beta 3. HNSCC products enhanced endothelial cell adherence to fibronectin and laminin, and beta 1 and beta 4 expression. These data show bi-directional enhancement of adherence to ECM and integrin expression among endothelial and tumor cells, which may facilitate metastasis and neovascularization.

The involvement of metabotropic glutamate receptors and their intracellular signalling pathways in sustained nociceptive transmission in rat dorsal horn neurons

The excitatory responses of individual dorsal horn neurons to cutaneous brush, repeated application of the C-fibre-selective chemical algogen, mustard oil, or to ionophoretic (1S,3R)-ACPD [a metabotropic glutamate receptor (mGluR) agonist] were monitored by extracellular recording. We have previously shown that the responses of dorsal horn neurons to mustard oil are inhibited by several selective antagonists of mGluRs. Effects of ionophoresis of the mGluR antagonists (R,S)-CHPG and L-AP3 and a range of selective inhibitors of intracellular signalling pathways were examined on evoked responses here. The results suggest that protein kinase C, phospholipase A2 and perhaps Ca2+/calmodulin kinase II play a role in mediating the sustained elevated activity of dorsal horn neurons that is incrementally elicited by repeated application of mustard oil, but probably make little contribution to sustained brush-evoked activity. Concurrence in the sensitivity of mustard oil- and (1S,3R)-ACPD-evoked activity to (R,S)-CHPG, L-AP3 and to inhibitors of intracellular signalling pathways, suggests that mGluRs are an important origin of these intracellular signals required for sustained nociception.

Treating tumor-bearing mice with vitamin D3 diminishes tumor-induced myelopoiesis and associated immunosuppression, and reduces tumor metastasis and recurrence

Metastatic Lewis lung carcinoma (LLC-LN7) tumors that secrete granulocyte/macrophage-colony-stimulating factor (GM-CSF) stimulate myelopoiesis and induce bone marrow-derived immunosuppressor cells that are homologous to granulocyte/macrophage progenitor cells. In vitro treatment of the LLC-LN7 cells with 1 alpha,25-dihydroxyvitamin D3 reduced tumor cell production of suppressor-inducing activity, although suppressor-inducing activity could be restored by reconstituting the tumor supernatants with recombinant GM-CSF. Treatment of mice having LLC-LN7 tumors with vitamin D3 reduced tumor production of GM-CSF and the frequency of myeloid progenitor cells. This was associated with a reduction in immunosuppressor activity and an increase in T cell function. Vitamin D3 treatment of mice having palpable tumors transiently retarded tumor growth, but caused a prominent reduction in tumor metastasis. Treating mice with vitamin D3 after tumor excision resulted in a reduction in the tumor-induced myelopoietic stimulation and associated immunosuppressive activity, and enhanced T cell function. These mice had a markedly reduced incidence of tumor recurrence. The results of this study suggest that vitamin D3 treatment of mice with GM-CSF-secreting tumors can interrupt the myelopoiesis-associated immunosuppressor cascade and, in turn, reduce tumor metastasis and recurrence.

Circadian characteristics of interleukin-6 in blood and urine of clinically healthy men

The cytokine interleukin-6 (IL-6) is a multi-functional small peptide molecule that is produced by various types of lymphoid and non-lymphoid cells and plays a central role in hematopoiesis, host defense mechanisms, and acute phase reactions, including regulation of inflammatory and immune responses. A high-sensitivity ELISA assay was applied to serum (S) and urine (U) samples available from 10 men (median age = 50y, range = 46-71y) in order to compare circadian characteristics of IL-6 between assays and in 2 biological fluids. S and U samples were collected at 3-h intervals for 24hrs beginning at 19:00h on May 14, 1993 (8 samples/subj) and frozen at -25 degrees C until analysis. IL-6 in U was adjusted for time & volume (pg/hr) and assigned to midpoint of collection interval. A significant time-effect was found by ANOVA and a high-amplitude circadian rhythm was detected by the least-squares fit of a 24-hr &/or 24+12-hr cosine for each assay. Higher serum IL-6 values were detected throughout the night, with a peak at 01:00h, and lower values throughout the day, with a nadir at 10:00h. In contrast, IL-6 values in urine were highest during the day, with a major peak in the afternoon at 17:30h and a minor peak at 08:30h, and lowest values overnight, with a nadir at 23:30h. Of interest, the rhythm in urinary IL-6 concentration (pg/ml) was more prominent than hourly excretion rate (pg/hr). Thus, endogenous IL-6 (and possibly other cytokine) levels may be significantly influenced by their large and predictable day-night variations and the biological fluid used.

Ineffective immune enhancement by IL-12 in tumor-bearing mice whose immune depression is mediated by suppressive granulocyte-macrophage progenitor cells

Lewis lung carcinoma (LLC-LN7) tumors stimulate myelopoiesis and induce immunosuppressive granulocyte-macrophage (GM)-progenitor cells. Treating mice having palpable tumors with IL-12 enhanced the frequency of GM-progenitors and did not diminish GM-suppressor activity. Proliferation of splenic T-cells of tumor-bearers to Con-A or to anti-CD3 plus IL-2 was suppressed; this was not enhanced by IL-12 treatment. Also not stimulated was T-cell secretion of IL-2 in response to autologous tumor, or the intratumoral T-cell content. IL-12 slightly increased splenic IFN-gamma secretion, and increased cytotoxicity of lymph node (but not spleen) cells toward autologous tumor. In these tumor-bearing mice that were immune depressed as a result of GM-suppressor cells, immune modulatory effects of IL-12 were marginal and did not affect tumor size or metastasis.

Circadian characteristics of circulating interleukin-6 in men

BACKGROUND

The cytokine interleukin-6 (IL-6) is a multifunctional small-peptide molecule that is produced by various types of lymphoid and nonlymphoid cells. It plays a central role in hematopoiesis, host defense mechanisms, and acute-phase reactions, including regulation of inflammatory and immune responses.

METHODS

Because a circadian time structure has been shown to characterize nearly every biologic function tested in human beings, including some cytokines, we sought to investigate the 24-hour pattern of circulating IL-6 in a group of 11 clinically symptom-free men (median age, 50 years; range, 46 to 72 years). Blood samples were obtained every 3 hours for 24 hours (eight samples per subject), and serum was frozen until analysis for IL-6 with a solid-phase ELISA.

RESULTS

Average IL-6 values ranged from 1.66 to 5.38 pg/ml, with lowest to highest values within 24 hours ranging from 1.20 to 7.58 pg/ml (120% to 531%) between subjects. On average, values were greater than the mean throughout the night, with a peak at 01:00 hours and less than the mean throughout the day, with a nadir at 10:00 hours. A significant time effect was found by analysis of variance; and a high-amplitude circadian rhythm was described by the least-squares fit of a 24-hour cosine (p < 0.001; amplitude, 41% +/- 5%; acrophase, 02:16 +/- 00:28 hours). In addition, a positive correlation between mean IL-6 levels and age was found (r = 0.63, p = 0.037).

CONCLUSIONS

Because monitoring of endogenous cytokine levels is suggested for assessing immune function and pathologic condition, clinical decisions and immunotherapies may be significantly influenced by the large and predictable day-night variations in endogenous cytokine production and bioactivity.

Immune parameters of mice bearing human head and neck cancer

A xenogeneic human head and neck squamous cell carcinoma (HNSCC) model in immunocompetent mice was evaluated for its requirement of cyclosporine for progressive tumor growth. Tumor growth and T cell functions were assessed in mice receiving cyclosporine treatment for various lengths of time. Tumor cells were injected s.c. on day 1 and cyclosporine was injected i.p. daily on days 1, 1-7, 1-14, 1-21, or for the entire 28 days of tumor growth. All mice developed tumors. These tumors were confirmed to be squamous carcinomas of human origin histologically and by positive staining for human MHC class I antigen expression. Tumors were largest in mice that received cyclosporine for days 1-21 or days 1-28. Increased tumor size was associated with increased serum levels of tumor-reactive antibodies, an increased intratumoral frequency of CD4+ and CD8+ cells, but a diminished production of interleukin-2 (IL-2) by the tumor infiltrate. Also correlating with increasing tumor size was splenomegaly, a decline in the frequency, but not the absolute levels, of splenic CD4+ and CD8+ cells, and a diminished capacity to proliferate in response to concanavalin A and to be stimulated to secrete IL-2. The HNSCC tumors contributed to the immune decline since T cell functions were more depressed in the tumor bearers than in control mice receiving only cyclosporine treatment. These results demonstrate that human HNSCC tumor xenografts can grow in mice even with limited cyclosporine treatment, and that the survival of these xenografts may, in part, be due to a tumor-induced decline in select T cell functions.

Production of nitric oxide and transforming growth factor-beta in developing and adult rat brain

Nitric oxide (NO) has been suggested to have a neurotoxic role in the brain, while transforming growth factor-beta (TGF-beta) has been considered to be a suppressor of inflammatory cytokine release. The amounts of these modulators that are released by rat brain cultures were measured for tissue obtained from rats of different maturational age groups: weanling (3 weeks), young (3 months), and middle-aged (12 months) rats. Basal levels of brain-derived NO increased with age. This was attributed to brain microglial-derived NO. Culturing of the brain tissue with LPS or PGE2 further increased the amount of NO elaborated from brain cultures of 3-week-old and 3-month-old rats to a level that was similar to the high amounts detected in unstimulated brain cultures from 12-month-old rats. Stimulation of brain cultures from 12-month-old rats did not further enhance NO levels. In contrast to the maturation-associated increase in NO production, levels of brain-derived bioactive TGF-beta declined with age. LPS and PGE2 increased the amount of bioactive TGF-beta released by brain cultures of each rat age group, but there nevertheless remained an age-related reduction in active TGF-beta levels. These results suggest a possible developmental association between an enhancement of brain-derived NO and a concomitant decline in brain TGF-beta.

Regulation of Lewis lung carcinoma invasion and metastasis by protein kinase A

Metastatic Lewis lung carcinoma (LLC-LN7) cells have increased protein kinase A (PKA) activity and are more invasive in vitro than are non-metastatic (LLC-C8) cells. To determine whether PKA mediates the in vitro invasiveness and in vivo metastatic capabilities of these tumor cells, the LLC variants were stably transfected to over-express the C alpha subunit of PKA, and thus to have increased PKA activity, or to express a mutant cAMP-resistant PKA R1 alpha subunit which blocks PKA activation. Wild-type LLC-LN7 tumor cells were invasive in vitro and in vivo, recurred after tumor excision and metastasized to the lungs. However, they lost these properties after transfection to express the mutant R1 alpha that blocks PKA activation. The non-invasive, non-recurring and non-metastatic LLC-C8 cells gained the capacity to invade, to recur following tumor excision and to metastasize when transfected to express the PKA C alpha subunit.

Regulation of cytoskeletal organization in tumor cells by protein phosphatases-1 and -2A

Non-metastatic Lewis lung carcinoma cells (LLC-C8) become more motile when protein phosphatases (PP-1 and -2A) are inhibited by okadaic acid, attaining the same level of motility as metastatic LLC (LLC-LN7) variants. This stimulation of LLC-C8 motility was tempered when protein kinase A activity was inhibited. We examined whether the okadaic acid-stimulated LLC-C8 motility was associated with alterations in the cytoskeletal organization so that these non-metastatic cells acquire the rounded morphology and diffuse cytoskeletal organization previously described for metastatic LLC-LN7 cells. Non-metastatic LLC-C8 are typically adherent during culture, achieving a spread morphology. Treatment of non-metastatic LLC-C8 cells with okadaic acid resulted in a contraction of most of their extended processes, formation of spikes and membrane blebs within 10 min, and complete cell rounding within 20 min for most of the cells. While the overall level of F-actin was minimally affected by the okadaic acid, its uniform distribution shifted to localization toward the periphery of the rounded cells, often concentrating at a single focus. Immunofluorescent staining for vimentin showed a similar shift to the cell periphery and similar capping. After okadaic acid treatment, the filamentous network of microtubules in non-metastatic LLC-C8 cells disappeared and was replaced with a diffusely staining distribution of beta-tubulin. These results show that PP-1 and -2A maintain cytoskeletal organization and that inhibition of this control reduces cytoskeletal organization and increases tumor cell motility.

Treating tumor-bearing mice with low-dose gamma-interferon plus tumor necrosis factor alpha to diminish immune suppressive granulocyte-macrophage progenitor cells increases responsiveness to interleukin 2 immunotherapy

Production of granulocyte-macrophage (GM) colony-stimulating factor by murine metastatic Lewis lung carcinoma cells (LLC-LN7) increases the number and distribution of GM progenitor cells that are suppressive to T cell responsiveness to interleukin 2 (IL-2). The presence of these GM suppressor cells can be diminished by treatment of LLC-LN7-bearing mice with low doses of 100 units IFN-gamma plus 10 units tumor necrosis factor alpha (TNF-alpha). The aim of this study was to determine whether treatment of LLC-LN7-bearing mice with IFN-gamma/TNF-alpha to diminish GM suppressor cell presence would increase the responsiveness to IL-2 immune stimulatory therapy (100-1000 IU, twice daily for 5 days). Treatment first with IFN-gamma/TNF-alpha and then also with low dose IL-2 increased both the numbers of CD4+ and CD8+ cells within the tumor and the levels of their expression of the p55 IL-2 receptor. These intratumoral T cells also had an increased cytolytic capacity toward autologous tumor cells and an increased capacity to proliferate and secrete IL-2. Such effects were observed to a lesser extent in mice that were treated with either IFN-gamma/TNF-alpha alone or with low doses of IL-2 only. The combination treatment regimen of IFN-gamma/TNF-alpha and then IL-2 was also significantly more effective at reducing the size of the primary tumor and the formation of metastatic lung nodules than were the individual treatments. These results show that treatment to minimize the presence of GM suppressor cells enhances the effectiveness of IL-2 to stimulate anti-tumor immune responses and to diminish tumor growth and metastasis.

Circadian rhythmometry of serum interleukin-2, interleukin-10, tumor necrosis factor-alpha, and granulocyte-macrophage colony-stimulating factor in men

Serum levels of four cytokines [tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-10 (IL-10)] were measured in nine diurnally active healthy adult male subjects at 3-h intervals during a 24-h period. Statistical evaluation by analysis of variance and/or the least- squares fit of a cosine model revealed significant 24-h rhythms for each cytokine. Although the amount of IL-2 in the serum was low, the levels fluctuated to form a single peak at approximately noon. In contrast, the other three cytokines exhibited a biphasic temporal pattern. In subjects with detectable TNF-alpha levels, the first peak occurred at 07:30 and the second at 13:30. IL-10 levels also exhibited a biphasic pattern, with one peak at 07:30 and the second 12 h later at 19:30. GM-CSF levels were last to rise, first peaking at approximately 13:30 and then again at 19:30. These results suggest temporal patterns that are unique for each cytokine, generally with daytime highs and nighttime lows.

Mechanisms of immune suppression in patients with head and neck cancer: presence of CD34(+) cells which suppress immune functions within cancers that secrete granulocyte-macrophage colony-stimulating factor

Production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by murine tumors has been shown to induce immune suppressive cells having homology with GM progenitor cells. The purpose of this study was to determine if human head and neck cancers secrete GM-CSF, if this is associated with an intratumoral presence of similar cells expressing the hematopoietic progenitor cell antigen CD34, and if such CD34(+) cells suppress functions of intratumoral T cells. This was evaluated with fresh head and neck cancers, and in some instances regional lymph nodes and control tissue. Ten of the 14 squamous cell carcinomas (SCCs) studied secreted greater than 5 ng GM-CSF/g tissue. GM-CSF was not secreted in significant levels by either the other cancer types or by control normal muscle. Each of the high GM-CSF-secreting SCCs, but none of the cancers that did not secrete GM-CSF, contained cells expressing the hematopoietic progenitor cell antigen CD34 that had the capacity to grow into colonies in soft agar. Available regional lymph nodes from patients with high GM-CSF-producing cancers also contained CD34(+) cells. Depletion of CD34(+) cells from dissociated cancers increased interleukin 2 secretion by the intratumoral lymphocytes while addition of the CD34(+) cells to dissociated cancers reduced interleukin 2 production, indicating that the presence of CD34(+) cells within GM-CSF-producing head and neck SCCs results in suppressed functional competence of lymphocytes within the SCCs. These results show that GM-CSF-secreting SCCs contain cells expressing the hematopoietic antigen CD34 which are inhibitory to the capacity of lymphocytes within the SCCs to secrete interleukin 2.

Serotonin regulation of T-cell subpopulations and of macrophage accessory function

The role of serotonin as an immune modulator was investigated by measuring the functional competence of T cells from control mice versus from mice whose intracellular stores of serotonin had been depleted by pretreatment with p-chlorophenylalanine (PCPA). While the proportions of splenic CD4+ and CD8+ T cells isolated from control and PCPA-treated mice were similar, the level of expression of the alpha-chain interleukin-2 receptor (IL-2R) was reduced on splenic CD4+ cells but not on CD8+ cells. Culture with the T-cell mitogen concanavalin A (Con A) failed to induce expression of the IL-2R on either CD4+ or CD8+ cells of PCPA-treated mice, although IL-2R was induced on control cells. The proliferative response to Con A by these spleen cells from PCPA-treated mice was also reduced compared to that by control spleen cells. Both expression of IL-2R and proliferation in response to Con A by spleen cells from serotonin-depleted mice were increased or completely restored by supplementation of the cultures with serotonin. Studies to identify the mechanisms for the reduction in T-cell activation when serotonin levels were reduced implicated a defect in the capacity of macrophages from PCPA-treated mice to provide accessory help for T-cell activation. Splenic macrophages from control mice were able to restore the blastogenic capability of lymphocytes from PCPA-treated mice, although macrophages from PCPA-treated mice were unable to support normal lymphocyte blastogenesis unless the cultures were supplemented with serotonin. These results show the requirement of autologous serotonin for optimal T-cell activation and suggest the importance of serotonin in macrophage accessory function for T-cell activation.

Eicosanoids and the immunology of cancer

Studies in both cancer patients and in animal tumor models have shown that immune defenses can mediate destruction of tumor, but these defenses are often functioning at a suppressed or suboptimal level. Frequently, prostaglandins, mainly PGE2, have been implicated in this tumor-associated subversion of immune function, with immune reactivities to tumor typically being enhanced by prostaglandin synthesis inhibitor. Both the tumor and tumor-induced host immune suppressive macrophages have the capacity to suppress immune functions through their production of PGE2. Although the inhibitory functions have been more widely studied, recent evaluations of the effects of PGE2 have led to the surprising realization that not all of the PGE2's effects are inhibitory to immune function. Summarized below are some of the well characterized inhibitory effects of PGE2, as well as the lesser studied stimulatory effects of PGE2 toward the effector cells that are considered to be important in the immune defense against cancer.

Local anaesthesia for inguinal herniorrhaphy--a neglected technique

Ninety-nine inguinal herniorrhaphies were performed under local anaesthetic blockade between 1980 and 1988. This represents 32% of this surgical teams herniorrhaphy operations. A follow-up interview was possible in 82 patients. Satisfaction was expressed by 77 patient (94%) although six of the interviewed patients (7.4%) had moderate/significant discomfort during the procedure. Four of the 99 patients (4%) developed a wound infection.