Biomedical subjects

Y Tendler

Publications and source records attributed to Y Tendler.

At least 19 recordsLinked to original sources

PubMed2000

Melatonin and colon carcinogenesis. III. Effect of melatonin on proliferative activity and apoptosis in colon mucosa and colon tumors induced by 1,2-dimethylhydrazine in rats.

Forty-eight two-month-old outbred female LIO rats were injected weekly with a single dose of 1,2-dimethylhydrazine (DMH; 21 mg/kg of body weight) administered s.c. for 15 consecutive weeks. From the day of the 1st injection of the carcinogen the part of rats were given five days a week during the night time (from 18.00 h to 08.00 h) melatonin dissolved in tap water, 20 mg/l. 10 rats were treated similarly with solvents and served as control. The experiment was terminated 6 months after the first injection of the carcinogen. Colon tumors (mainly adenocarcinomas) developed in a hundred percent of rats exposed both to DMH or to DMH plus melatonin. However, descending colon carcinomas were observed in 65 % of rats exposed to DMH plus melatonin against 100% in those exposed to DMH alone (p < 0.01). The multiplicity of colon tumors was also reduced in rats under the influence of melatonin. This effect is correlated with the significant inhibitory effect of the pineal hormone on mitotic index and with stimulating effect of melatonin on the relative number of apoptotic cells (TUNEL-method) in colon tumors. Long-term treatment with melatonin was followed also by the decrease in the area of lymphoid infiltrates in the colon mucosa of tumor-bearing rats.

1,2-Dimethylhydrazine↗

PubMed2000

Quantification of p53 expression in the nervous system.

The transcription factor p53 is a short lived protein that is thought to be associated with cellular proliferation and apoptosis. In the current study, we present a protocol to measure p53 expression across both the central and peripheral nervous systems of transgenic and parental mice using the enzyme linked immuno-substrate assay (ELISA), chloramphenicol acetyl transferase reporter assay (CAT) and immunohistochemistry approaches. The profiles of the ELISA tissue data of CD1 mice were compared to the CAT assay data of the p53-promoter-driven CAT gene transgenic mice. Subsequently, high resolution immunohistochemical analysis of positive tissues in both mouse strains were evaluated. As the p53 protein is apparently subject to high turnover, the comparison of the more stable CAT data to the pan p53 ELISA assay should effectively complement each other in identifying which nervous system structures express p53. ELISA analysis alone could give ambiguous data. Immunohistochemical studies confirmed and further defined p53 expression in several regions of the nervous system. Significantly, p53 promoter-driven CAT expression was visualized in the Purkinje cells of the cerebellum and in the cornea as well as in the retina of the eye. This approach for the analysis of very short half-life proteins in the nervous system should be transferable to the study of other proteins.

Animals↗

PubMed2000

Transplacental effects of maternal feeding with high fat diets on lipid exchange and response of the splenic lymphoid system in mice offspring exposed to low doses of carcinogen.

We studied whether feeding pregnant female mice with different fats affects lipid exchange and activity of the splenic lymphoid system in offspring exposed to low doses of carcinogen. Female mice were fed diets with either 7% or 15% corn oil or olive oil. The 4-week-old offspring of these mice were transferred to a chow diet, and exposed to a low dose of the carcinogen, dimethylbenz(a)antracene (2 mg/kg). Results of experiments were studied 5 months later. Concentrations of polyunsaturated linoleic and oleic acids were determined in the blood and liver of mothers and offspring. The activity of the splenic immune system in offspring was studied using immunohistochemical methods for evaluating the number of different types of lymphocytes (B and T cells), mitotic and apoptotic indexes and the number of Fas-positive lymphocytes. Serum concentrations of the fatty acids examined were unchanged in the blood of the mothers and their offspring. Concentration of both linoleic and oleic acids was significantly higher in the liver of mothers fed the 15% olive-oil or corn-oil diets. This high level was maintained in linoleic acid in offspring of mothers fed the 15% olive-oil diet. Spleen weight was higher in offspring of mothers fed a 15% corn-oil diet compared to those fed the 7% corn-oil diet. The 15% olive-oil diet slightly decreased the weight of the spleen compared to counterparts fed the 15% corn-oil diet. Immunohistochemical studies showed that the olive diet, partially of 15%, significantly stimulated B-cell blast transformation. The finding reflects the reaction of B lymphocyte-producing splenic zones to the carcinogenic effect, though to a weak extent. T lymphocyte-producing zones did not respond to the diets studied, probably due to the weak carcinogenic effect and lack of tumor appearance. The Fas activity of both B and T cells in the spleen was stimulated by the carcinogen and enhanced by feeding the mothers on the olive-oil diet. Maternal feeding with a diet rich in olive oil before pregnancy results in stimulation of morphological and functional attributes of the splenic immune system of the offspring, particularly related to producing of B lymphocytes.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed2000

Apoptosis and apoptosis-related proteins (Fas, Fas ligand, Blc-2, p53) in lymphoid elements of human ovarian tumors.

Different types of lymphocytes have different roles in tumor suppression. Thus, their expression of apoptosis-related proteins (ARP - Fas and Fas ligand, bcl-2, p53) in lymphocytes and their apoptosis were analyzed immunohistochemically in ovarian tumors of different grades. Ovaries without oncologic disorders had few lymphocytes, mainly T cells, and no ARP. Benign cysts presented features of weak immune reaction: small lymphoid infiltration and few lymphocytes. The ARP were present in 13.7% to 23.5% of the lymphocytes, and apoptosis was rare. In borderline tumors, expansion of lymphoid infiltrates and increased density of lymphocytes resulted in a tenfold rise in total lymphocytes, reflecting intensification of the immune response. Most lymphocytes were T cells (92%) predominated by CD8+ cells that were in direct contact with tumor epithelial cells. ARP species were found in 47% to 65% of the lymphocytes, and apoptosis in 2.2%. In carcinomas with ligh lymphoid infiltration, lymphocytes were 2.5 times more abundant, and the apoptotic index as well as the number of CD20+ and CD25+ lymphocytes rose sharply, whereas bcl-2 positive lymphocytes decreased to 8% of their number in borderline tumors. In carcinomas with low lymphoid infiltration, the total lymphocyte count decreased eightfold compared to carcinomas with high lymphoid infiltration, reflecting the deep subcompensation of the lymphoid system. Few p53-positive lymphocytes were found in the carcinomas. In conclusion, we found a positive correlation between apoptosis and the numbers of CD4+ or CD8+ lymphocytes in epithelial ovarian tumors. This correlation could reflect the antitumor activity of T cells. However, the high expression of ARP studied by immune cells at the vicinity of the tumor ARP reveals the lymphoid vulnerability to apoptosis, resulting in devastation of the lymphoid tissue, and consequently in tumor progression.

Adenocarcinoma↗

PubMed2000

Apoptosis and apoptosis-related proteins (Fas, Fas ligand, bcl-2, p53) in macrophages of human ovarian epithelial tumors.

Apoptosis and the apoptosis-related proteins (ARP) (Fas, Fas ligand (FasL), bcl-2 and p53) were analyzed in macrophages of different human ovarian epithelial tumors. Few macrophages were found in ovaries of women without oncologic disorders. In ovarian benign cysts, macrophagic density reached 4.9+/-1.2 per 50,000 microm2, most were present in lymphoid-macrophagic infiltrates of the sub-epithelial stroma (3.7+/-0.5% of the area of a slide), and 23.4% were Fas and FasL positive. In borderline tumors, the expanse of lymphoid infiltrates increased to 15.6% of the area of a slide, and the number of macrophages increased 2.4-fold compared to benign cysts. Of the macrophages, 83-88% expressed Fas and FasL, few had bcl-2 and CD25 receptors, and isolated ones were apoptotic. In carcinomas with high lymphoid-macrophagic infiltration, the infiltrate occupied 17.5% of the slide and macrophages amounted to 12.1+/-1.5/50,000 microm2. Many macrophages were in regions of grouping apoptosis of tumor epithelial cells and significantly fewer expressed Fas, FasL and bcl-2. Macrophages destroyed by apoptosis accounted for 4.6%. In carcinomas with low lymphoid-macrophageal infiltration, the area of the last was 5.1% of the slide. There were 8.6+/-0.8 macrophages/50,000 microm2, mainly at the margins of zones of necrosis and of tumor cells' grouping apoptosis. Extensive macrophagic infiltration into tumor parenchyma is one way by which the host immune system destroys tumors. Fas and FasL appear in macrophages of benign cysts, but in borderline tumors and in carcinomas with low infiltration their concentration increases sharply, to 79.8% and 96.6%, respectively. In 4.5% of these cells, apoptosis of macrophages was seen. The findings suggest that macrophages participate in the transfer of ARP to tumor epithelial cells, thereby inducing their apoptosis, but undergoing the simultaneous apoptosis.

Aged↗

PubMed1999

Tissue-specific p53 expression in the nervous system.

P53 is a transcription factor that has been found to be expressed in association with cell proliferation and apoptosis. Previously, bacterial chloramphenicol acetyl transferase (CAT) enzymatic expression was predominantly found in the testes of p53 promoter driven-CAT transgenic mice. In the current study, we extended this study to survey p53 expression across both the central and peripheral nervous systems of the same strain of transgenic mice as well as their parental strain. High levels of p53 promoter driven-CAT activity was observed in the cerebellum, hippocampus, hypothalamus, pons, thalamus and upper cerebral spine. Furthermore, we consistently found unexpectedly high levels of p53 promoter-driven CAT expression in the eyes. These observations were reinforced by p53 protein analysis using a p53 pan ELISA assay. Immunohistochemical studies confirmed and further defined p53 expression in several regions of the nervous system. Significantly, p53 promoter-driven CAT expression was visualized in the Ammon horn of the hippocampus, in the Purkinje cells of the cerebellum and in the cornea as well as in the retina of the eye. Furthermore, strong p53 protein expression was found in the cornea of the parental mouse strain. p53 ELISA demonstrated a profile of p53 protein concentration, which correlate well with the high p53 promoter-driven CAT activities observed in the cerebellum, hindbrain, hypothalamus, thalamus, hippocampus, whole eyes as well as with the low CAT activities observed in the cortex and spinal cord. In both of these assays considerable p53 promoter activity and p53 protein levels were found in post-mitotic non-dividing cells.

Animals↗

PubMed1999

Contaminant eluted from solid-phase plasmid affinity-purification protocol columns is not found using liquid-phase methods and can be prevented.

The preparation of high quality plasmid DNA is a necessary requirement for most molecular biology applications. We compared four different large plasmid preparation protocols, which were based on either a liquid-phase approach (Triton lysis) or purification of alkaline lysis bacterial extracts followed by supercoiled plasmid purification on affinity columns. Two host Escherichia coli strains, JM 109 and INValphaF', were used to grow the test plasmids for comparison of product plasmid DNA produced from the four different plasmid isolation methods. While the DNA grown in E. coli strain JM109, prepared by liquid-phase Triton lysis was appropriately restricted by 12 restriction enzymes, this was not the case for any of the JM109-grown DNA purified by any of the affinity column solid-phase approaches. In contrast to this, when the plasmid DNA was grown in E. coli strain INValphaF', most restriction enzymes cut DNA appropriately, irregardless of the plasmid preparation protocol used. It seems that an impurity commonly eluted with the DNA from all three of the solid-phase DNA columns had an equal effect on the above enzymes using the common host strain JM109, but not strain INValphaF'.

Chromatography, Affinity↗

PubMed1999

Diagnosis of chlamydial infection by direct enzyme-linked immunoassay and polymerase chain reaction in patients with acute follicular conjunctivitis.

BACKGROUND: Acute follicular conjunctivitis is a clinical diagnosis common to multiple etiologies, of which chlamydial infection requires specific antibiotic treatment. PURPOSE: This prospective study was designed to evaluate Chlamydia trachomatis as the cause of acute follicular conjunctivitis by two sensitive tests: direct enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). METHODS: Conjunctival scrapings from patients presented with untreated acute follicular conjunctivitis were examined by ELISA and PCR, and patients were followed up for prolongation of the disease course. RESULTS: All 36 consecutive patients presented with acute follicular conjunctivitis were negative for Chlamydia trachomatis by ELISA and PCR. None of the patients had a prolonged course of more than 4 weeks or required treatment with systemic antibiotics as would be expected from chlamydial infection. CONCLUSIONS: Chlamydia trachomatis was probably not responsible for the acute follicular conjunctivitis in this series, and ELISA and PCR may not be cost effective for evaluation of acute follicular conjunctivitis due to chlamydial infection. Further evaluation of the cost effectiveness of these tests is required in chronic follicular conjunctivitis.

Acute Disease↗

PubMed1999

Morphological and morphometric studies of the splenic antitumor immune response, elicited by liposome-covered soluble p53 kDa antigen, in chemically-induced rat colon cancer.

We evaluated the splenic morphometric changes in rats treated with carcinogen to study development of anti-cancer immune response. When liposome-covered soluble 53 kDa antigen (s53) was injected into these rats, significant tumor-suppression was seen and the percentage of tumor-free animals rose from 15.4% in non-vaccinated rats to 53.8%. In the spleens of carcinogen treated rats that did not develop tumors, activity of B lymphocytes increased significantly. This was manifested by the expansion of the germinal centers to 50.9% of the follicular area reflecting depletion of B cells, and the decrease of the mantle layer to 48.9% of the follicles. A similar picture was seen with T lymphocytes: the area of the marginal zone decreased to 55.2% of the T zone of the white pulp, and that of the periarterial lymph sheaths (PALS) to 33.6%. In tumor-bearing rats features of the immune decompensation were seen: the germinal centers increased to 96.5% of the follicular area, and the mantle layer and PALS decreased significantly. Vaccination prevented these effects, especially in tumor-bearing rats: the PALS occupies 30.4% of the white pulp and the marginal zone 56.1%, and the mantle layer occupied 58.1% of the follicular zone. Similar changes were found in vaccinated rats without tumors reflecting the compensatory character of the immune reaction in vaccinated rats. In conclusion, we found that treatment with carcinogen followed by vaccination with the s53-liposomes complex stimulated the activity of the splenic B, and to a lesser degree the T systems.

Animals↗

PubMed1999

Effects of low doses of carcinogen and different antibodies on the splenic lymphoid system of p53 transgenic mice: morphometric and immunohistochemical studies.

The role of the splenic immune system in the development of high sensitivity of p53 transgenic mice to low doses of carcinogen and vaccination was investigated immunohistochemically and morphometrically. Spleens were obtained from human p53 promoter-chloramphenicol acetyl transferase transgenic mice, grouped as follows: 1, untreated controls; 2, exposed to dimethylhydrazine (DMH); 3, and 4, vaccinated with polyclonal antibodies to soluble-53 kDa protein (s53); 5, vaccinated with monoclonal PAb DO1; 6, vaccinated with monoclonal PAb 421; 7, vaccinated with polyclonal alphaH-p53 antibody. Mice in groups 4-7 were treated with DMH after the course of vaccination. Six months later all the mice were tumor-free, but effects of the low dose carcinogen were distinct in the splenic immune system. They were mainly manifested in blast transformation: the total number of lymphocytes and lymphoblasts decreased to 56.5% of the controls. The total of lymphoid cells in the follicles (B zone) and periarterial lymph sheath (T zone) declined, reflecting moderate insufficiency of the spleen's lymphoid system. Vaccination of transgenic mice with antibodies to soluble-p53 elicited mainly a B system response, with lesser T system involvement. Only few signs of B system insufficiency were found in these mice. Vaccination of mice with different antibodies, with subsequent carcinogen treatment, caused changes in the spleen that were similar to those described for DMH alone, but varied with different anti-p53 antibodies. Vaccination with polyclonal antibodies to soluble-p53, or with monoclonal antibodies PAb DO1 or PAb 421, stimulated the splenic activity of T system, and therefore can decrease the tumorigenic effect of carcinogens.

1,2-Dimethylhydrazine↗

PubMed1999

Apoptosis and apoptosis-related proteins in the epithelium of human ovarian tumors: immunohistochemical and morphometric studies.

BACKGROUND: The origin of malignant ovarian tumors is the subject of considerable controversy, which may be resolved by elucidation of molecular mechanisms of tumorigenesis. Therefore we have undertaken the study of apoptosis in these tumors. METHODS: Apoptosis and the expression of its related proteins, Fas, Fas ligand (FasL), bcl-2 and p53, in epithelial cells of human ovarian tumors of different histological grades, were determined immunohistochemically and morphometrically. RESULTS: Apoptosis-related proteins were absent from ovarian epithelia of patients afflicted with non-cancerous diseases. In ovarian tumors, the distribution of individual proteins varied, and depended on the grade and type of tumor. Fas and FasL were highly expressed in all tumors, while epithelial cells expressing bcl-2 were abundant in benign tumors, but their numbers significantly dwindled with the progression of malignancy. Cells expressing p53 were found in borderline tumors, and their numbers increased with malignancy, inverse of bcl-2 expression. Apoptotic tumor cells were scarce in borderline tumors and abundant in carcinomas. Grouping apoptosis was found in approximately 60% of the carcinomas. CONCLUSIONS: The initial development of ovarian tumors is accompanied by high epithelial expression of Fas, FasL and bcl-2 proteins, while apoptosis and p53 proteins are detected only at later stages of tumorigenesis.

Apoptosis↗

PubMed1999

Transplacental effects of IgG generated against soluble 53 kDa protein on the splenic lymph system of rat progeny exposed to carcinogen: rate of apoptosis, proliferation of lymphocytes and expression of Fas and Fas ligand proteins.

BACKGROUND: We have previously shown that vaccination with IgG generated against the soluble 53 kDa (s53) protein modified the splenic response to carcinogens. Here we studied whether such immunization could affect the splenic lymphatic system of the offspring. METHODS: Offspring of normal female rats or of rats immunized with anti-s53 IgG were exposed to a carcinogen (dimethyl-benz(a)antracene). After 4 months, their spleens were resected and evaluated immunohistochemically for lymphocyte proliferation, apoptosis and apoptosis-related proteins (Fas and Fas ligand), in tumor-free and tumor-bearing animals. RESULTS: Spleens of progeny of unvaccinated rats had a significant decrease in the areas of follicles, germinal centers and the mantle layer after exposure to carcinogens, while maternal vaccination resulted in a significant expansion of the progeny's splenic follicles and germinal centers, the zones of B cell proliferation. The area of periarterial lymph sheaths (PALS) expanded in these offspring, reflecting activation of the T-zone. Maternal vaccination also resulted in a significant rise of Fas ligand-positive lymphocytes in the follicles and PALS of their tumor-free offspring. Tumorigenesis stimulated the Fas activity of B and T cells in the spleens, and this was much enhanced by maternal vaccination. CONCLUSIONS: Maternal vaccination before pregnancy results in altered morphological and functional attributes of the splenic immune system of the offspring. This increased immunoreactivity could reduce the risk of tumors in progeny of vaccinated mothers.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1996

Heparin induces apoptosis in human peripheral blood neutrophils.

Programmed cell death, by apoptosis, has been shown to play an important role in the regulation of haemopoiesis. Using trypan blue exclusion for distinguishing intact membranes, flow cytometry for detection of sub G1 peak and in situ terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL), this study shows that heparin induces apoptosis in vitro in human peripheral blood neutrophils. The known anti-proliferative effect of heparin in several in vitro cell systems has therefore to be interpreted in the light of apoptosis. In addition, apoptosis may help explain the anti-inflammatory effects resulting from the interaction between vessel wall heparan sulphate and chemoattracted peripheral blood neutrophils.

Apoptosis↗

PubMed1996

Comparative study of the role of serum levels of p53 antigen and its tumor cell concentration in colon cancer detection.

The role of serum levels of p53 antigen in detection of colon cancer was studied in different groups of cancer and noncancer patients and was compared with the results of immunohistochemical analyses. The p53 antigen was isolated from the human serum as a cytoplasmic fraction using the recently described new type of columns for affinity chromatography, gel fiberglass columns (Zusman and Zusman, 1995). Its concentration was detected by high performance liquid chromatography. The serum level of the p53 antigen significantly increased in cancer patients (3.6 mg ml(-1)) as compared to its concentration in patients with benign tumors (1.7 mg ml(-1)) or in patients with noncancer disorders (0.49 mg ml(-1)), and this was found to be a result of higher concentration of p53 protein in tumor cells. Coefficient of correlation between cellular concentration of p53 protein and its serum level was 0.44 in noncancer lesions and 0.48 in cancer patients. Serum levels of p53 antigen was shown to be highly active either in patients with noncancer lesions or in patients with cancer (r = 0.46 and 0.51 respectively), whereas the cell determination of p53 protein was effective only among noncancer patients (r = 0.61) but not in cancer patients (r = 0.22). The findings suggests that serum determination of p53 antigen can perhaps reveal this oncoprotein already in the early stages of cancer or even predict the putative development of cancer. The possibility to use the serum-levels of p53 antigen in the follow up patients with chronic diseases and to detect transformation of these diseases into cancer, or monitoring former cancer patients in order to detect as early as possible the incidence of recurrent cancer is discussed.

Antigens, Neoplasm↗

PubMed1995

Immunohistochemical detection of p53 protein expression in HPV-induced condyloma acuminatum.

Immunohistochemical peroxidase staining for p53 protein was performed on 22 condyloma acuminatum tissue samples from patients infected with human papillomavirus (HPV). The purpose of our study was to understand the benign character of this syndrome. The patients studied were infected by HPV type 6 and 11. Two monoclonal antibodies, PAbs DO-1 and 240, were used to detect the p53 protein. Overexpression of wild-type p53 was found in the nuclei of the basal cell layers. In healthy tissues and non-infected patients no p53 protein expression was detected. We would like to speculate that infection with HPVs and their viral protein E7, which is implicated in disruption of normal growth, may regulate the induction of wild-type p53 over-expression, as is known for DNA-damaging agents such as UV- or X-radiation.

Adolescent↗

PubMed1994

Histochemical studies of progressive p53 mutations during colonic carcinogenesis in Sprague-Dawley rats induced by N-methyl-N-nitro-nitrosoguanidine or azoxymethane.

We studied the increasing expression of the p53 tumor suppressor gene in Sprague-Dawley rats, chemically induced to develop colon cancer. p53 expression was evaluated histochemically at various stages of tumor progression (during a period of 40 weeks) that can be followed by colonic hyperproliferation labeled by 3H-thymidine incorporation. We found that high level nuclear expression of p53 protein correlates with progression of malignancy in carcinogen-induced animals, whereas cytoplasmic staining is related to the onset and early development of malignancy.

Adenocarcinoma↗

PubMed1987

Serum cholesterol levels three years before and after viral hepatitis.

The serum cholesterol levels 3 years before and 3 years after an acute episode of hepatitis in 12 men aged 21-36 were compared to those in 22 age-matched controls. Serum cholesterol increased significantly during the acute icteric phase of the illness and remained elevated for 3 years after recovery. We conclude that cholesterol metabolism does not return to the prehepatitic state even 3 years after recovery.

Adult↗

PubMed1987

Asymptomatic microscopic hematuria in pilots.

Pilots were examined in order to determine whether the cumulative incidence or point prevalence of asymptomatic microscopic hematuria is associated with air duty. The cumulative incidence of recurrent microscopic hematuria over a 12-15-year period was 11.3%(17/151) in fighter pilots, 10.0%(8/80) in helicopter pilots, and 13.8% (11/80) in transport pilots. Similarly, the point prevalence of microscopic hematuria in those who had flown the day prior to the urinalysis was no higher than found in the control group. We conclude that air duty does not cause microscopic hematuria either chronically or during the day after the stress of air flight.

Adult↗