Search PubMed⌕ Search

Biomedical subjects

W Den Otter

Publications and source records attributed to W Den Otter.

At least 55 records · Page 3Linked to original sources
PubMed1994

Specific T-cell factors that initiate cellular immune responses are produced by CD4-, CD8-, V beta 8- lymphocytes and are present in nude mice.

The antigen-specific suppressor inducer T-cell factors (TsiF) specific macrophage-arming factor (SMAF) and mast cell-arming T-cell factor (MTCF) are produced by lymphocytes that have a Thy 1+, Lyt-1+, CD4-, CD8-, and V beta 8- phenotype. The SMAF- and MTCF-producing lymphocytes are positive for the monoclonal antibody (mAb) 14-30, which is directed against TsiF and also binds SMAF and MTCF. The SMAF-producing lymphocytes are negative for mAb 14-12, which is directed against suppressor effector T-cell factors. The MTCF-producing lymphocytes are probably CD3+. The CD3 phenotype of SMAF-producing lymphocytes could not be established in the biological assays. Lymphocytes mediating the classical (24 hr) delayed-type hypersensitivity (DTH) response are Thy 1+, CD3+, CD4+, CD8-, V beta 8+. SMAF- and MTCF-producing lymphocytes were also detected in congenitally athymic (nude) mice. We conclude from these results that (i) the subset of lymphocytes (CD4-, CD8-, V beta 8-) that produces SMAF and MTCF (and is involved in the initiation of the cellular immune response) is different from the subset (CD4+, V beta 8+) that exerts effector functions, like DTH or cell-mediated immunity. (ii) In case of a CD3+ phenotype of SMAF- and MTCF-producing lymphocytes, this CD3+, CD4-, CD8- phenotype together with their presence in nude mice suggests that these lymphocytes may bear a gamma delta T-cell receptor (TCR), although an alpha beta TCR positive phenotype cannot be excluded. (iii) Since SMAF- and MTCF-producing lymphocytes bind mAb 14-30, these TsiF can be associated with the plasma membrane of the lymphocytes by which they are produced.

Animals↗
PubMed1994

Effects of sequential intravesical administration of mitomycin C and bacillus Calmette-Guérin on the immune response in the guinea pig bladder.

It has been suggested that intravesical treatment with mitomycin C (MMC) before instillation of bacillus Calmette-Guérin (BCG) improves the antitumor activity of BCG in human bladder cancer. Therefore, we studied the immunological effects of sequential intravesical treatment with MMC and BCG in the guinea pig. Four weekly intravesical instillations with MMC preceded six weekly intravesical BCG instillations. The delayed-type hypersensitivity (DTH) skin reaction evoked by tuberculin purified protein derivative (PPD) in guinea pigs receiving BCG intravesically appeared slightly earlier in animals pretreated intravesically with MMC than in phosphate-buffered saline (PBS)-pretreated animals. However, after completing BCG instillations no differences in DTH reaction were observed between these treatment groups. The extent of the local inflammatory reaction in the bladder wall, as well as the parameters measured in the draining iliacal lymph nodes (i.e., the weight, the number of leukocytes, and the composition of leukocyte subpopulations), did not differ in animals treated with BCG alone or in combination with MMC. A slight increase in the MHC class II expression on the bladder urothelium was shown if MMC and BCG treatment was combined. The adherence of mycobacteria to the bladder wall, measured using 3H-labeled mycobacteria, dit not differ between MMC/BCG- and BCG-treated animals. We conclude that MMC does not enhance the immune response against mycobacteria. Therefore, we hypothesize that a possible increased antitumor activity by the combination of MMC and BCG might be due to separate, rather than synergistic, effects of the drugs, namely a cytostatic effect of MMC on tumor cells and a local immune response in the bladder evoked by BCG.

Administration, Intravesical↗
PubMed1994

Local bacillus Calmette-Guérin therapy for bovine vulval papilloma and carcinoma.

Thirty cows from a pedigree Friesian dairy herd with bovine vulva papilloma and carcinoma were treated by intralesional injections of live bacillus Calmette-Guérin (BCG). This treatment induced total regression of all of six carcinomas. Whilst, after treatment, limited regression was also observed in advanced papillomas, BCG has little or no effect on the early stages of papillomas. This is the first study of BCG therapy in this type of cancer.

Animals↗
PubMed1994

Antitumor effect of locally injected low doses of recombinant human interleukin-2 in bovine vulval papilloma and carcinoma.

In many human clinical trials and in various animal tumor models, the antitumor effect of high doses of systemically applied interleukin-2 (IL-2) is tested. Our studies focused on the effects of low doses of locally injected IL-2. In this paper, the effect of local injection of low doses of IL-2, i.e. a total dose of 25,000-50,000 units, into papillomas or carcinomas of the bovine vulva is described. In 19 out of 23 (83%) cows treated with IL-2 an effect on the tumor load was observed; in three of these animals, complete regression was obtained. In the majority of cases, regression was not restricted to the tumors injected with IL-2.

Animals↗
PubMed1993

An avaII restriction fragment length polymorphism in the insulin-like growth factor II gene and the occurrence of smooth muscle tumors.

To detect a previously described AvaII restriction fragment length polymorphism (RFLP) in the human insulin-like growth factor II (IGF-II) gene we used the polymerase chain reaction (PCR) and genomic sequencing. The RFLP is located in exon 9 of the IGF-II gene at nucleotide 820 (GenBank accession number X07868) as a C-->T transition. Digestion with AvaII reveals a two-allele polymorphism, an a allele in which the AvaII site is not present, and a b allele. In healthy Dutch persons (n = 26), the frequency of the a allele was 62%. A similar a allele frequency was found in groups of Japanese (53%, n = 65) and Chinese (54%, n = 84), while in a French group the frequency was significantly lower (25%, n = 52). In Dutch individuals that had developed benign (n = 11; all women) and malignant (n = 9; 2 women and 7 men) smooth muscle tumors, a significantly higher frequency of 83% for the a allele was found. Since there was no difference between the presence of the a and b alleles in normal and tumor tissue of the same individual, the higher a allele frequency was not due to mutation in the IGF-II gene or loss of heterozygosity. There was no correlation between the presence of the a allele and expression of the IGF-II gene. The data reveal a correlation between homozygosity for the a allele and the occurrence of smooth muscle tumors. Women homozygous for the IGF-II a allele are more prone to develop a leiomyoma than women who are heterozygous or homozygous for the b allele. Furthermore, in both women and men the risk for leiomyosarcomas seems to be higher in a allele homozygotes.

Alleles↗
PubMed1993

Human natural killer cells: a convenient purification procedure and the influence of cryopreservation on cytotoxic activity.

The recognition of natural killer cells as a lymphoid subpopulation with a distinct set of surface markers has led to the development of a variety of antibody-based purification methods. In this paper we describe a rapid, three-step negative selection protocol for the purification of human natural killer (NK) cells from the mononuclear cell fraction, which is obtained by the centrifugation of peripheral blood on Ficoll-Paque. Subsequently, monocytes and B lymphocytes are removed by adherence to nylon wool and T lymphocytes by panning with anti-CD3. With this procedure, CD3-, CD16/56+ NK cells are purified about five-fold, from 12 +/- 3% in the starting population to a final purity of 61 +/- 11%. A further increase to > or = 70% is obtained, if an extra Ficoll centrifugation step is included. The recovery of NK cells (50%) is significantly higher than is usually achieved by previously described procedures. Furthermore, we show that activation of cytotoxicity, with concomitant changes in target specificity, occurs when frozen/thawed NK effector cells are kept in culture in order to regain their pre-freezing cytotoxicity levels.

Cell Separation↗
PubMed1993

Dualistic effects of cis-diammine-dichloro-platinum on the anti-tumor efficacy of subsequently applied recombinant interleukin-2 therapy: a tumor-dependent phenomenon.

The efficacy with which disseminated SL2 and P815 tumors, in syngeneic DBA/2 mice, can be eradicated with low-dose recombinant interleukin-2 (rIL-2) therapy is about equal. Treatment (i.p.) of DBA/2 mice, injected i.p. with SL2 or P815 cells on day 0, with rIL-2 (Proleukin) on days 10 to 14 results in a cure rate of 50 to 60% in each case. The in vitro sensitivity of SL2 and P815 cells to cis-diammine-dichloro-platinum [II] (cisplatin) is also comparable, although P815 appears to be slightly more sensitive. In vivo, however, therapy with cisplatin is far less effective against P815 than against SL2. In the DBA/2-SL2 model, at all doses tested, combination therapy with cisplatin (administered on day 2) and rIL-2 (administered on days 10-14) resulted in anti-tumor efficacy greater than that of either drug separately. In contrast, in the DBA/2-P815 model, cisplatin decreased the anti-tumor efficacy of subsequently applied rIL-2 therapy. As the only difference between the 2 tumor models is the tumor itself, the success of combination therapy with cisplatin and rIL-2 was dependent on tumor characteristics. We suggest that in these 2 tumor models, neither the sensitivity of these tumors to cisplatin nor their growth and dissemination patterns were responsible for the contrasting results of combination therapy in these models. Instead, tumor-dependent immune-modulating effects of cisplatin may be the cause of these effects. These immune-modulating effects may comprise (a) effects of cisplatin on the tumor cells, resulting in changes in their susceptibility to immune effector cells, or changes in their immunogenicity; (b) activating or suppressive effects of cisplatin on immune effector cells; or (c) a combination of these effects. These effects could then either synergize or antagonize with the immune activating properties of rIL-2.

Animals↗
PubMed1993

Detection of calcitonin and calcitonin gene-related peptide mRNA in human medullary thyroid carcinoma. A retrospective study.

In situ hybridization finds many applications in modern pathology. In many cases, special attention is paid to the processing of the tissues prior to in situ hybridization. In order to investigate the value of RNA in situ hybridization (RISH) in retrospective studies, we performed RISH for calcitonin and calcitonin gene-related peptide (CGRP)-I and -II mRNA in eight medullary thyroid carcinomas processed in 1981-1983. RISH was successful with radioactive calcitonin and CGRP-I probes. With biotinylated probes, only calcitonin-specific probes gave adequate results. The concentrations of CGRP mRNA were probably too low to be detected by non-radioactive RISH. The results of RISH were correlated with the immunohistochemical localization of the polypeptides. The results matched in all cases except one, where hybridization for calcitonin mRNA was found, but no immunoreactive calcitonin polypeptide. We conclude that RISH can be successfully used for retrospective analysis, even after long storage of tissue embedded in paraffin.

Calcitonin↗
PubMed1993

Locoregional therapy with polyethylene-glycol-modified interleukin-2 of an intradermally growing hepatocellular carcinoma in the guinea pig induces T-cell-mediated antitumor activity.

Therapy with repeated intratumoral and perilymphatic administration of relatively low doses of polyethylene-glycol(PEG)-modified interleukin-2 (IL-2) in the syngeneic guinea pig line 10 (L10) hepatocarcinoma results in significant local tumor growth inhibition and a delay in development of regional lymph node metastases of more than 3 weeks when compared to controls. Occasionally animals are cured of tumor. The mechanism of this antitumor activity was studied. The antitumor activity of locoregionally administered PEG-IL-2 was abrogated by pretreatment with polyclonal anti-thymocyte serum, indicating that the observed tumor growth inhibition was a T-cell-mediated phenomenon. Besides the locoregional tumor growth inhibition, a systemic effect was recorded as the growth of a second tumor cell inoculum at the contralateral side was inhibited as well. Furthermore, those animals cured after PEG-IL-2 therapy developed specific immunity against the L10 tumor and this immunity could be transferred to naive animals by spleen cells. Immunohistological observations of the tumor site revealed a slight increase of helper and cytotoxic T cell subpopulations after PEG-IL-2 therapy. More pronounced, however, was the rise in number of eosinophilic granulocytes present in the stroma surrounding the tumor cells. Involvement of cytotoxic cells in the antitumor effects of PEG-IL-2 could not be demonstrated: regional lymph node cells and spleen cells obtained immediately after therapy (day 15) or on day 21 showed no cytotoxic activity in vitro against L10, K562, Daudi and line 1 (L1) target cells. In conclusion, locoregional therapy with PEG-IL-2 induced a a systemic T-cell-mediated antitumor response. As no cytotoxic T cell activity was measured, however, the underlying mechanism is most likely a T-helper response. Eosinophils at the tumor site may be tumoricidal but further experiments must reveal the role of these cells in the PEG-IL-2-induced tumor regression.

Animals↗
PubMed1993

Critical factors for liposome-incorporated tumour-associated antigens to induce protective tumour immunity to SL2 lymphoma cells in mice.

Physical and immunogenic properties of reconstituted membranes designed for the presentation of tumour-associated antigens (TAA) to the immune system are described. Proteins and lipids of crude membranes of SL2 murine lymphosarcoma cells were partially solubilized with octylglucoside. Reconstituted membranes, consisting mainly of unilamellar vesicles with a diameter of 0.03-0.15 microns, were formed by detergent removal and were purified by floatation in a discontinuous sucrose gradient to remove non-lipid-bound protein. Subcutaneous immunization of syngeneic mice with reconstituted membranes or with purified reconstituted membranes induced protection against an intraperitoneal challenge with 10(3) viable SL2 cells. Reconstituted membranes were more immunogenic than crude membranes in immunoprotection experiments when compared on the basis of protein dose. Detergent removal was required to obtain an immunogenic presentation form of SL2 membrane antigens and to avoid toxicity associated with the detergent. Reconstitution of SL2 membranes in the presence of exogenous phospholipid slightly increased the fraction of protein that associated with the reconstituted membranes. However, the immunogenicity of the solubilized membrane TAA was not significantly affected by the presence of exogenous phospholipid. The reconstitution procedure described may be useful in identifying membrane factors required for the induction of immune responses against TAA. The versatility of the system may be employed to develop safe alternatives for whole-cell vaccines.

Animals↗
PubMed1993

Interleukin-2 in cancer treatment: disappointing or (still) promising? A review.

The central question to discuss in this review is whether the results of interleukin-2 (IL-2) treatment are still disappointing or again promising. Although in the (recent) past application of high doses of systemically applied rIL-2 has led to some success, the overall results are not as one had hoped. Considering these poor results it seems clear that the application of high systemic doses rIL-2 was not a good choice. IL-2 has been used more or less as a chemotherapeutic compound in the highest tolerable dose. This has led to a great number of unwanted toxic side-effects. In addition, these doses mainly stimulated nonspecific lymphokine-activated killer activity through low-affinity IL-2 receptors, which does not lead to systemic immunity. On the other hand, several groups have shown that application of intratumoral low doses of IL-2 can be highly effective against cancer and without toxic side-effects. Significant tumor loads constituting up to 6% of the total body weight of a mouse were eradicated after treatment with low-dose rIL-2 given locally. Furthermore local treatment can lead to eradication of a tumor at a distant site. This type of therapy is effective in many systems namely against different tumor types in mice, hepatocellular carcinoma in guinea-pigs and vulval papilloma and carcinoma and ocular carcinoma in cattle. Low-dose IL-2 is very effective in experimental animals if it is given relatively late after inoculation of the tumor cells. In other words, it seems necessary that some sort of immune reaction has started or is developing before low doses of rIL-2 effectively stimulate it. In fact there is strong evidence that T lymphocytes, both CD4+ and CD8+ cells, are directly involved in the process leading to induction of specific immunity. In our opinion rIL-2 therapy should therefore aim at the stimulation of such (originally weak) specific immune reaction. Under these conditions also systemic immunity can be induced. In conclusion, application of rIL-2 as a modality for cancer treatment is still promising. High priority should be given to a further delineation of the mechanisms involved after local application. The method of giving IL-2 systemically in the highest tolerable dose should be abandoned. Specific stimulation of the immune system by low-dose rIL-2 is a much more promising option.

Animals↗
PubMed1993

Histological analysis of IL-2 induced regression of murine solid SL2-tumors.

When DBA/2 mice are inoculated both intraperitoneally (i.p.) and subcutaneously (s.c.) with syngeneic SL2 lymphoma cells and treated i.p. on day 10-14 with 20,000 units IL-2/day, about 50% of the mice reject both the ascitic tumour and the s.c. tumour. During IL-2 therapy large areas of necrosis appear in the solid SL2 tumours between day 12 and 15. Immunohistochemical studies show that only a small number of infiltrating cells is present in the tumours. The percentage of macrophages (MHC-II+) in the tumours is about 1 and the percentage of T-lymphocytes (alpha beta-TCR+) about 0.5. No differences in the numbers of infiltrating cells are seen in untreated and IL-2 treated tumour bearing mice. The tumour surrounding infiltrate consists mainly of mononuclear cells: about 50% macrophages, 20% CD8+ cells, and 15% CD4+ cells. No tumour-infiltrating cells were found that express the IL-2 receptor. We conclude that direct cytotoxic activity of tumour infiltrating cells cannot account for the rapid occurrence of necrosis. When L3T4+ cells were eliminated by treating the mice with alpha-L3T4 monoclonal antibodies before tumor inoculation and treatment with rIL-2, tumor eradication did not occur. So, L3T4+ helper T-cells are essential for IL-2-mediated tumour regression. Exogenous rIL-2 is not directly responsible for the induced tumour regression. A significant stagnation of intratumoural bloodflow is observed after histological analysis; yet it still needs to be determined whether this is the primary cause or consequence of the observed necrosis.

Animals↗
PubMed1993

Interleukin-2-containing liposomes: interaction of interleukin-2 with liposomal bilayers and preliminary studies on application in cancer vaccines.

Interleukin-2 (IL-2) incorporation in liposomes was studied under different conditions. Information was obtained on the mechanism of interaction of glycosylated recombinant IL-2 with liposomal bilayers. This information was utilized to formulate liposomes with high levels of incorporated IL-2. Multilamellar vesicles were prepared by hydration of a lipid film with an IL-2 solution. The incorporation efficiency, measured with a bioassay after forced release of IL-2 from the vesicles, was strongly dependent on the charge of the liposomes and the pH and ionic strength of the hydration medium. Negatively charged liposomes composed of phosphatidylcholine/phosphatidylglycerol (9:1) and prepared with IL-2 dissolved in 10 mM NaAc/270 mM glycerol, 0.1% BSA, pH 5, showed the highest incorporation efficiency (81%) among the investigated preparations. This type of liposome was selected for further study. Electrostatics play a crucial role in the process of IL-2 association with this type of liposome. Initial studies concerning induction of protective tumor immunity by immunization with reconstituted membranes with muramyl tripeptide phosphatidylethanolamine indicate that coinjection of IL-2-containing liposomes provided a significant enhancement of the immune response.

Animals↗
PubMed1993

Growth of cultured human glioma tumour cells can be regulated with histamine and histamine antagonists.

The 50% survival time for low grade astrocytomas is 50 months and for high grade astrocytomas it is 13 months, underlining the need for new therapies. Several reports show that in vivo histamine antagonists cause retardation of tumour growth in some animal models and prolonged survival in cancer patients. Therefore we have tested the growth modulating effects of histamine and histamine antagonists on human glioma cultures. Twelve freshly excised human gliomas were cultured and tested for their in vitro sensitivity to histamine and histamine antagonists. Four continuous glioma cell lines were used to confirm the glioma-specificity of the effects observed in the primary cell lines. In low serum concentration (0 or 1%) the growth of 5/9 primary glioma-derived cultures could be stimulated with 0.2 mM histamine, and in 4/5 cases with 0.2 microM histamine. One mM of the histamine H2-receptor antagonist cimetidine could inhibit the growth of 4/5 primary glioma cultures when tested in 1% human AB serum, and of 6/13 cases when tested in 1% FCS. Lower concentrations (down to 1 microM) were less effective. The histamine H1-receptor antagonist pyrilamine gave variable results. The specificity of the effects is indicated by the absence of a generalised toxic effect, by the observation that the antagonist-induced inhibition could be reversed with histamine, and by the correlation of the obtained cimetidine-induced growth inhibition with the maximal growth rate of the primary cell lines in 10% FCS. The observed cimetidine-induced inhibition of the in vitro proliferation of gliomas suggests that cimetidine is a relevant candidate for the in vivo growth inhibition of these tumours.

Adult↗
PubMed1993

Cell surface glycoconjugates as possible target structures for human natural killer cells: evidence against the involvement of glycolipids and N-linked carbohydrate chains.

Natural killer (NK) cells can spontaneously kill various malignant cells, but the susceptibility towards NK cells differs greatly among different types of tumour cells. The molecules, which are recognized by NK cells, have not yet been identified, but there is ample evidence that target cell surface glycoconjugates are involved in the interaction with NK cells. In this report, we show that the recognition of K562 target cells by human NK cells depends on the presence of protein-bound determinants, implying that glycolipids are not the primary target structures on K562 cells. The NK susceptibility of K562 cells was not altered by enzymic removal of various cell surface carbohydrates or oligosaccharides, mostly related to N-linked carbohydrate chains. Treatment of K562 cells with 1-deoxynojirimycin and 1-deoxymannojirimycin, inhibitors of N-glycan processing, resulted in drastic alterations in the carbohydrate phenotype of the cell surface, as could be shown by flow cytometric analysis of the lectin-binding properties of the cells. Despite these clear changes in N-glycosylation, the NK susceptibility of K562 cells remained unaffected. Summarizing, the results described in this report show that potential target structures for NK cells are protein bound, but the involvement of a specific (N-linked) carbohydrate determinant in the interaction between NK cells and target cells could not be established.

1-Deoxynojirimycin↗
PubMed1993

Involvement of the omental lymphoid organ in the induction of peritoneal immunity against tumor cells.

The omental lymphoid organ (OLO) is a part of the greater omentum composed of vascularized spots containing lymphocytes, plasma cells and macrophages located in a regular pattern between fat cells. To gain insight in the involvement of the OLO in the induction of immunity against tumor cells in the peritoneal cavity, we studied the penetration of tumor cells into the OLO after intraperitoneal, subcutaneous and intravenous injection. Furthermore we analyzed the tumoricidal activity of macrophages isolated from the OLO. Our results indicate that the OLO is only infiltrated by tumor cells directly from the peritoneal cavity, but not by subcutaneously or intravenously injected tumor cells unless they have reached the peritoneal cavity. Bromodeoxy-uridine labelled tumor cells can be detected in the OLO within 10 min after i.p. injection. The penetration is facilitated by the induction of fenestrations between the mesothelial cells (lining the OLO) after intraperitoneal injection of the tumor cells. These fenestrations can also be seen after nonspecific stimulation of the peritoneal cavity. Macrophages isolated from the OLO of mice immunized against syngeneic as well as allogeneic tumor cells express a significant cytotoxicity, which (at least in the syngeneic situation) precedes the cytotoxicity of the macrophages isolated from the peritoneal cavity. In conclusion, our data support the hypothesis that immune reactions against intraperitoneally injected tumor cells are initiated in the OLO leading to 'peritoneal immunity' against these tumor cells.

Animals↗
PubMed1993

Application of a mixed imaging sequence for MR imaging characterization of human breast disease.

Single slice MR images were obtained from 9 normal breasts, 17 breasts with benign tumors, and 11 breasts with malignant tumors using an interleaved (mixed) spin echo (SE) inversion-recovery (IR) imaging sequence. SE and IR MR images were synthesized with variable repetition, echo and inversion times from the mixed sequence data. These images were used to qualitatively evaluate the contrast possibilities available when imaging the breast with MR imaging. Proton T1 and T2 relaxation times were determined for normal breast tissues and malignant and benign breast tumors from pure T1 and T2 images calculated using the mixed sequence data. The mean T1 value in benign tumors of 1,049.02 +/- 40.31 was found to be significantly longer (p < 0.0001) than the mean value of malignant tumors (876.09 +/- 27.83) and normal tissues (795.64 +/- 21.12). The value of T2 in benign tumors (89.15 +/- 8.33) was significantly longer (p < 0.01) than the value of T2 in normal tissues (62.82 +/- 4.06). The mixed sequence can be applied to improve image contrast between malignant tumors, benign tumors, and normal tissues of the breast and can potentially differentiate between these tissues in vivo.

Breast Diseases↗