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Biomedical subjects

J Trojan

Publications and source records attributed to J Trojan.

At least 55 records · Page 3Linked to original sources
PubMed1998

Treatment of hepatocellular carcinoma with the cellular tumor vaccines generated by in vitro modification of tumor cells with non gene transfer approaches.

Anti-tumor immune responses are mediated primarily by T cells. Down regulation of major histocompatibility complex (MHC) and the molecules that costimulate the immune responses is associated with defective signaling of tumor cells for T cell activation. In vitro fusion of autologous tumor cells with antigen presenting cells (APCs) or treatment of tumor cells with a combination of cytokines significantly increased the expression of MHC class I and adhesion molecules on tumor cell surfaces that costimulate host immune responses. The hybrid cells generated by fusion of tumor cells with APCs and the tumor cells treated in vitro with a combination of cytokines and pre-incubated with a bispecific monoclonal antibody (bi-Mab) cross-linking antigen on tumor cells to CD28 on T cells, become immunogenic and able to stimulate naive T cells with generation of tumor specific cytotoxic T cells both in vitro and in vivo. Immunization with the modified tumor cells elicits an immune response mediated by both CD4+ and CD8+ T cells. This response protected against a parental tumor cell challenge and cured established tumors. The approach was effective in both low immunogenic and non-immunogenic tumor systems. Modification of tumor cells with tumor:APC fusion or the two-step procedure may provide a strategy for development of tumor vaccines that is effective for cancer immunotherapy.

Animals↗
PubMed1998

Induction of apoptosis in rat hepatocarcinoma cells by expression of IGF-I antisense c-DNA.

BACKGROUND/AIMS: We have developed a gene therapy strategy based on the observation that insulin-like growth factor I (IGF-I) is necessary for the acquisition and maintenance of the transformed phenotype in hepatocarcinoma. This strategy consists in transfecting the rat hepatoma cell line with an episomal vector expressing the antisense IGF-I c-DNA under the control of the metallothionein I promoter inducible by zinc, decreasing therefore the level of IGF-I in these cells. The transfected clones lost their tumorigenic properties, and were able to induce, in vivo, the regression of an established tumor in syngeneic rats. To understand the loss of tumorigenic properties of these transfected clones, we have quantified, by different approaches, the number of apoptotic cells according to the level of IGF-I expression. METHODS: IGF-I antisense synthesis in transfected cells was stimulated using zinc. We then characterized and quantified apoptosis, in these transfected clones, by morphological and DNA fragmentation analyses, flow cytometry and comet assay. RESULTS: We have demonstrated that IGF-I inhibits the development of apoptosis in parental cells, that the transfected clones are able to restore the spontaneous apoptotic programme, and that apoptosis increases massively when overexpression of IGF-I antisense is caused by zinc stimulation of the metallothionein I promoter. CONCLUSION: The present results allow us to conclude that the level of apoptotic pathway in liver cell lines is directly related to the amount of IGF-I deficiency.

Animals↗
PubMed1998

Rapid microsatellite analysis of paraffin embedded tumour specimens from patients with hereditary non-polyposis colorectal cancer.

In screening for hereditary non-polyposis colorectal cancer (HNPCC)--an autosomal dominant disorder characterised by mutations in mismatch repair genes--detection of microsatellite instability is an important diagnostic criterion. The mono- or dinucleotide repeat DNA sequences are usually amplified from formalin fixed, paraffin embedded tissue by polymerase chain reaction after numerous time consuming steps including deparaffinisation, DNA extraction, and purification. A rapid single step method for direct DNA analysis is described, based on preincubation of paraffin embedded tissue with Triton X-100 followed by DNA amplification with fluorescence labelled primers and electrophoresis in an automated sequencer. This procedure allows precise allele sizing and analysis of genetic instability, is more efficient and time saving, reduces the risk of contamination, and is therefore of particular interest in screening for HNPCC.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1998

Modulation of human thyrotropin oligosaccharide structures--enhanced proportion of sialylated and terminally galactosylated serum thyrotropin isoforms in subclinical and overt primary hypothyroidism.

Enhanced sialylation of thyrotropin (TSH) prolongs its metabolic clearance rate and thus increases the hormone's in vivo bioactivity. This has been shown for hypothyroid rats and for recombinant human TSH, but there are few data on the sialylation of human serum TSH. The aim of this work was to further study sialylated human serum TSH, its precursors bearing terminal galactose residues, and the role of pharmacological doses of thyrotropin-releasing hormone (TRH) on their secretion under different degrees of primary hypothyroidism. We analyzed serum TSH in patients with subclinical (n = 9) and overt primary hypothyroidism (n = 13) compared with euthyroid individuals (n = 12) and human standard pituitary TSH (IRP 80/558). Blood was drawn before and 30 min after intravenous administration of 200 micrograms TRH, and TSH was purified by immunoaffinity concentration. The content of sialylated (sialo-) TSH and isoforms bearing terminal galactose (Gal-TSH, asialo-Gal-TSH) was measured by Ricinus communis (RCA 120) affinity chromatography in combination with enzymatic cleavage of sialic acid residues. TSH immunoreactivity was measured by an automated second generation TSH immunoassay. Pituitary TSH contained 16.5 +/- 0.8% Gal-TSH. In euthyroid individuals the proportion of Gal-TSH was 14.6 +/- 1.9%, whereas TSH in patients with subclinical and overt primary hypothyroidism contained 23.9 +/- 3.5% (P < 0.05 vs euthyroid individuals) and 21.1 +/- 1.7% Gal-TSH respectively. The mean ratio of asialo-Gal TSH was 23.8 +/- 0.6% for pituitary TSH, 35.7 +/- 4.2% in euthyroid individuals, 48.0 +/- 3.3% in patients with subclinical, and 61.5 +/- 3.8% (P < 0.001 vs euthyroid individuals) in patients with overt primary hypothyroidism. For pituitary TSH the calculated proportion of sialo-TSH was 6.5 +/- 0.2%, for euthyroid individuals 20.3 +/- 2.8%, for patients with subclinical hypothyroidism 24.1 +/- 3.0%, and for patients with overt primary hypothyroidism 40.7 +/- 3.0% (P < 0.001 vs euthyroid individuals). The proportions of Gal-TSH, asialo-Gal-TSH, and sialo-TSH did not differ significantly before and after TRH administration in the individuals studied. Our data show that patients with subclinical and overt primary hypothyroidism have a markedly increased proportion of serum TSH isoforms bearing terminal galactose and sialic acid residues, which may represent a mechanism for the further stimulation of thyroid function. Pharmacological doses of TRH cause an increased quantity of TSH to be released, but do not significantly alter the proportion of sialylated or terminally galactosylated TSH isoforms.

Adult↗
PubMed1998

Limited value of fluorine-18-fluorodeoxyglucose PET for the differential diagnosis of focal liver lesions in patients with chronic hepatitis C virus infection.

AIM: The differentiation of HCC from liver metastasis or benign disorders by imaging studies based upon morphological aspects may be difficult. METHOD: In order to evaluate the role of tumour metabolism, we performed FDG-PET (whole-body PET and transmission-corrected regional scans of the liver as well as the SUV determined 60 min after injection of FDG) in ten consecutive patients with HCV-associated focal liver lesions. Definite diagnosis was established after ultrasound-guided liver biopsy followed by histopathological examination. These results were compared with ultrasound, computed tomography, serum anti-p53, and p53 protein expression. RESULTS: The histologic examination revealed a HCC in five patients, regenerative nodules in three patients, and liver metastasis (primary malignancy: one adenocarcinoma and one neuroendocrine tumour) in the remaining two patients. Three of ten lesions were detectable by FDG-PET: two HCCs and one metastatic adenocarcinoma. Seven lesions were not distinguishable by FDG-PET (three HCCs, three regeneration nodules and one metastatic neuroendocrine tumour). In each patient hepatic lesions were visible either by ultrasound or CT. Both tumours (metastatic adenocarcinoma, moderately well-differentiated HCC) with the strongest expression of p53 also presented with highly increased FDG uptake. CONCLUSIONS: FDG-PET is not superior to ultrasound or CT and therefore does not allow the non-invasive differentiation of HCV-associated focal liver lesions. Tissue-diagnosis by means of liver-biopsy followed by histopathological examination remains the gold-standard for the differentiation of HCV-related liver lesions. The finding of the relationship of p53 protein overexpression with the SUV needs further confirmation.

Adult↗
PubMed1997

Immediate recovery of psychomotor function after patient-administered nitrous oxide/oxygen inhalation for colonoscopy.

BACKGROUND AND STUDY AIMS: Previous studies have shown that patients inhaling-self-administered nitrous oxide/oxygen as a sedative/analgesic medication for colonoscopy were ready to leave the endoscopy unit on average sooner than those given conventional intravenous premedication. The aim of this study was to define the time course of recovery after nitrous oxide/oxygen sedation or intravenous opiate/benzodiazepine premedication for colonoscopy. PATIENTS AND METHODS: Consecutive colonoscopy patients were randomized to receive either a 50% nitrous oxide/oxygen mixture (n = 12), or pethidine 25-50 mg and midazolam 2.5 mg (n = 15), or no sedation (n = 10). Psychomotor function was assessed by multiple-choice reaction time, hand-eye co-ordination, and letter deletion tests before and at 15-minute intervals after colonoscopy, with the assessment carried out by an observer blinded to the sedation regime. RESULTS: The mean duration and tolerance of the procedure were similar in the three study groups. Patients receiving nitrous oxide/oxygen mixture were judged (by clinical observation) to recover more quickly than those given conventional sedation (median 8 min, range 3- 25 min, vs. median 16 min, range 3-50 min). Recovery, as judged by a return to baseline in psychomotor function tests, was complete within 30 minutes in all patients receiving the nitrous oxide/oxygen mixture, compared to 50 minutes in those given conventional intravenous sedation. CONCLUSIONS: The rapid recovery observed with nitrous oxide/oxygen sedation for colonoscopy suggests that it is safe for patients to travel unescorted after the procedure. Driving may also be safe soon after nitrous oxide/oxygen sedation, but this requires further clarification.

Analgesia, Patient-Controlled↗
PubMed1996

Presence of MHC-I and B-7 molecules in rat and human glioma cells expressing antisense IGF-I mRNA.

Tumor cells frequently express the insulin-like growth factor I (IGF-I). Recently we demonstrated that rat glioma cells when transfected with a vector encoding antisense IGF-I cDNA lost tumorigenicity and induced a tumor specific immune response involving CD8+ lymphocytes. Here we show that the cultured transfected cell lines, rat C-6 glioma, human primary glioma and mouse teratocarcinoma, expressed an increased level of MHC-I and of co-signaling B-7 molecules. This increased expression of MHC-I and B-7, demonstrated by 51Cr release complement dependent cytoxicity assay and by immunostaining flow cytometry analysis, could contribute to the final immune recognition of glioma immunogenicity.

Animals↗
PubMed1996

[Immunotherapy of tumors expressing IGF-I].

Recently we demonstrated that rat glioma cells when transfected with a vector encoding antisense IGF-I c-DNA lost tumorigenicity and induced a tumor specific immune response involving CD8+ lymphocytes. Here we showed, using immunostaining flow cytometry analysis, that the transfected cell lines, rat C-6 glioma and rat LF hepatoma, expressed an increase level of MHC-class I, and even the amount of MHC-I was found to be higher in the transfected hepatoma, than in the transfected glioma cells. This increased expression of MHC-I could contribute to the final immune recognition of tumour immunogenicity.

Animals↗
PubMed1995

Expression of serum albumin and of alphafetoprotein in murine normal and neoplastic primitive embryonic structures.

Alphafetoprotein (AFP), a major serum protein synthesized during the embryo-fetal and postnatal period (in the yolk sac, then in the liver), is also an oncoprotein. The intracellular presence of AFP and of serum albumin (SA) in normal and neoplastic neural crest and neural tube derivatives was previously demonstrated. In this work we have studied the comparative expression of AFP and SA in primitive neuroectoblastic structures of mouse embryos (6 and 7 days "post coitum") and mouse teratocarcinomas (derived from the PCC4 cell line). Using immunofluorescence technique, antibodies to SA gave a positive reaction in embryos of 7 days, while AFP was not detected during this period. By mRNA in situ hybridization, SA mRNA gave a strong signal in both 6 and 7 day embryos, whereas AFP mRNA gave a weak signal only in 7-day embryos. The distribution of SA and AFP and their mRNAs was investigated in primitive neuroectoblastic structures of the teratocarcinomas by in situ hybridization and immunostaining. Only SA protein was detectable by immunostaining. SA mRNA gave a strong signal in differentiating structures as well as in undifferentiated cell clusters. AFP mRNA was observed only in differentiating structure. Dot-blot hybridization indicated that the level of SA transcripts was at least 6-fold higher than that of AFP transcripts in the teratocarcinomas investigated. In teratocarcinoma-bearing mice injected intraperitoneally with 125I-radiolabeled SA and AFP, significant accumulations of both SA and AFP were demonstrated in the tumors, SA being about 3-fold higher than that of AFP after normalization to quantity of uptake in liver. External in vivo photoscanning confirmed this relationship of accumulated radiolabeled proteins. The last observation could be useful in vivo for diagnosis of teratocarcinoma. We conclude that the expression of SA relative to AFP and the external cellular uptake of SA relative to AFP are similar in normal embryonic developing tissues and in the corresponding morphologically neoplastic tissues of the teratocarcinomas. The same SA:AFP relationship constitutes an oncofetal marker of primitive neuroectoblastic structures.

Animals↗
PubMed1995

Serum thyrotropin (TSH) heterogeneity in euthyroid subjects and patients with subclinical hypothyroidism: the core fucose content of TSH-releasing hormone-released TSH is altered, but not the net charge of TSH.

The aims of the present study were to determine the influence of brief subclinical hypothyroidism on the isoforms of serum thyrotropin (TSH) and to examine the net charge of TSH in different metabolic states. Sera were obtained from euthyroid subjects (n = 7) and from patients with subclinical hypothyroidism (n = 8) before and 30 min after the intravenous administration of 200 micrograms thyrotropin-releasing hormone (TRH). The TSH from human pituitary extracts (IRP 68/38), basal and TRH-stimulated serum TSH was immunoconcentrated and further analysed by isoelectric focusing (IEF) and lentil lectin affinity chromatography. TSH immunoreactivity was determined in each specimen or fraction with an automated highly sensitive chemiluminometric TSH assay. We found that basal TSH in subclinical hypothyroidism, and TRH-released TSH in euthyroidism and in subclinical hypothyroidism is distributed in a similar neutral to acidic pattern, which significantly differs from the more alkaline to neutral isoform pattern of intrapituitary TSH (P < 0.05). IEF analysis of pituitary standard TSH revealed 3 major peaks (pI values 7.5; 6.6; 5.8) whereas in most euthyroid or subclinically hypothyroid subjects 5 peaks were found. Lentil lectin affinity chromatography revealed that TRH-released TSH in euthyroid subjects has more core fucose residues than TSH from patients with subclinical hypothyroidism (64.6 +/- 6.7 vs 12.5 +/- 2.7%, P < 0.0001). Thus pituitary standard TSH seems to be less mature material than circulating TSH. Perhaps no alteration in the IEF pattern of TSH was detected during early hypothyroidism because sialylation of TSH was increasing as sulfatation was decreasing. Nevertheless, a change in the core fucose content of TSH was detectable by lentil analysis.

Adult↗
PubMed1994

Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation.

Teratocarcinoma is a germ-line carcinoma giving rise to an embryoid tumor with structures derived from the three embryonic layers: mesoderm, endoderm, and ectoderm. Teratocarcinoma is widely used as an in vitro model system to study regulation of cell determination and differentiation during mammalian embryogenesis. Murine embryonic carcinoma (EC) PCC3 cells express insulin-like growth factor I(IGF-I) and its receptor, while all derivative tumor structures express IGF-I and IGF-II and their receptors. Therefore the system lends itself to dissect the role of these two growth factors during EC differentiation. With an episomal antisense strategy, we define a role for IGF-I in tumorigenicity and evasion of immune surveillance. Antisense IGF-I EC transfectants are shown to elicit a curative anti-tumor immune response with tumor regression at distal sites. In contrast, IGF-II is shown to drive determination and differentiation in EC cells. Since IGF-I and IGF-II bind to type I receptor and antisense sequence used for IGF-II cannot form duplex with endogenous IGF-I transcripts, it follows that this receptor is not involved in determination and differentiation.

Animals↗
PubMed1994

[Diagnosis, therapy and screening of multiple endocrine neoplasia type I (MEN I) in four endocrinologic centers].

BACKGROUND: Multiple endocrine neoplasia type I (MEN I) is a hereditary disease characterised by involvement of several endocrine organs (parathyroid, anterior pituitary, pancreatic islet cells and other). In order to build up a German MEN I-register a questionnaire was developed. PATIENTS: In four centres we diagnosed 29 cases of MEN I (average age 53 years, range 27 to 72 years, 21 women, eight men). RESULTS: In 25 patients (86%) we found a primary hyperparathyroidism, in 15 patients (52%) an adenoma of the anterior pituitary (seven patients with growth hormone-secreting adenomas, five patients with prolactinomas, two patients with hormone-inactive and one patient with an ACTH-secreting adenoma), in ten patients (34%) a neoplasm of the pancreatic islet cells (six patients with gastrinomas, four patients with insulinomas and two patients with multihormone tumors) and in ten patients (34%) other endocrine tumors (five carcinoid tumors, three adenomas of the adrenal cortex, one papillary thyroid carcinoma and one thymic tumor). In nine cases nephrolithiasis was the leading symptom of primary hyperparathyroidism. All female patients with prolactinomas developed secondary amenorrhea. In three cases gastrinomas caused duodenal ulcers and three insulinomas were detected by fasting hypoglycemia. A primary hyperparathyroidism was most frequently combined with an adenoma of the anterior pituitary (21%). Detailed screening of 13 families early revealed MEN I in eleven cases. CONCLUSIONS: The manifestation of an endocrine disease in MEN I should initiate further diagnostics. Having established the diagnosis of MEN I, a meticulous work-up of all family members is warranted. The set-up of a register by the successfully tested questionnaire will support these activities and facilitate further research of new genetic markers, follow-up and treatment.

Adult↗