H9N2 influenza viruses from Israeli poultry: a five-year outbreak

Since 2000, hundreds of H9N2 viruses have been isolated from all types of domestic birds. Although H9N2 is a low-pathogenicity virus, disease has been observed in all types of poultry in the field. Clinical signs ranged from very mild disease to high morbidity and mortality when the virus was associated with a secondary pathogen. Because of the wide range of the virus and the great losses it caused, initially a local vaccination program was implemented, but mass vaccination was quickly authorized. A local strain, isolated in 2002 was selected and is currently in use as an inactivated vaccine. An intensive operation is in progress to characterize the isolates. Several genes (hemagglutinin [HA], neuraminidase, nonstructural protein, nucleoprotein, and matrix) were sequenced, revealing three main groups: the first group included two isolates from 2000, the second group included isolates from 2001 to the beginning of 2003, and the third group included all isolates from 2003 to date. The differences between the second and third groups, in a part of the HA gene, ranged from 3.49% to 6.97% (average 4.57%) of the nucleotides. Similar differences were recorded in the other tested genes. These data could indicate the probable introduction of distinct progenitor viruses into the Israeli poultry population. Furthermore, sequencing of the HA protein of some Israeli isolates revealed the presence of L216 in the binding site; this finding was typical of the H9N2 viruses isolated from humans, which raises the possibility of an influence on host specificity and virulence.

Expression of apoptosis and apoptosis-related proteins in microvessels of human ovarian epithelial tumors

We performed an immunohistochemical analysis of apoptosis and the expression of apoptosis-related proteins (ARP) such as Fas and Fas ligand (FasL), bcl-2 and p53 in human ovarian epithelial tumors. Fas and FasL were abundant in endothelial cells of microvessels, and were observed, at times, in the myocytes of small arteries and veins, in parietal or in obstructive thrombi and fibroblasts. Apoptosis was also noticed in the endothelial cells of capillaries and sinuses. The expression of bcl-2 or p53 was rare. We found that the progression of tumor development was accompanied by considerable changes in the microvessels of ovarian tumors. These changes are probably related to the effect of ARP that are expressed by tumor epithelial cells, lymphocytes and macrophages. We suggest that the ARP are released as a result of necrosis of these cells and are taken up by cells of microvessels and by the cellular remnants of blood clots. The effect of tumors on the microvasculature can be regarded as an angiopathy that results in necrosis and hemorrhage within the tumoral tissue and enhances the progression of the malignancy.

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.

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.

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.

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.

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.

Response of the spleen of Balb/c and p53-transgenic mice to low doses of carcinogen and to polyclonal antibodies generated against the soluble 53 kDa protein

BACKGROUND

We have previously reported that p53-transgenic mice are highly sensitive to low doses of a carcinogen and to vaccination with soluble 53 kDa antibodies, compared to normal mice. The splenic manifestation of this strain dependent hypersensitivity was investigated immunohistochemically and morphometrically.

METHODS

The spleen was obtained from Balb/c and human p53 promoter-CAT transgenic mice. Mice had either been treated with the carcinogen dimethylhydrazine (DMH), vaccinated before DMH treatment with polyclonal IgG generated against the soluble 53 kDa protein, or left untreated.

RESULTS

Significant differences in the splenic structures were found between the strains compared, including the area occupied by the white and red pulps, the periarterial lymphoid sheath (PALS) and the marginal zone, and in the number of lymphoblasts and lymphocytes. Exposure to DMH stimulated the immune response, but in transgenic mice the number of B and T lymphocytes and especially helper T lymphocytes was significantly lower than in Balb/c mice. Vaccination followed by DMH injections did not improve the insufficiency of the immune response in transgenic mice. In transgenic mice, the number of B lymphocytes in follicles was almost half and the total number of cells in PALS and the number of T lymphocytes were only 71% and 60% respectively in BALB/c mice. In the marginal zone, macrophages proliferated as lymphocytes decreased.

CONCLUSIONS

Insufficiency of the immune system after exposure to a carcinogen is more pronounced in transgenic mice, and is mainly related to the B-cell system. It may stem from defects in B lymphocytes or from inherent differences in their maturation and regulation. The increase in the number of macrophages, dendritic cells and neutrophils illustrates the compensatory processes that can remedy this developing immune insufficiency.

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.

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.

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.

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.

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.

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'.

Tissue-specific expression of the p53 tumor-suppressor gene in the intestine of transgenic mice exposed to DMH and p53 antibodies

We studied the tissue-specific expression of the p53 gene in different parts of the intestine of mice treated with low doses of a carcinogen and exposed to different p53 antibodies. The human p53 promoter-CAT transgenic mice were immunized with different p53 antibodies (monoclonal - PAb 421 and DO1, and polyclonal - H-p53 and anti-soluble p53 IgG) and then exposed to low doses of dimethylhydrazine (DMH). Enzymatic CAT activity was determined in the ileum and colon 8 weeks later after the final injection of DMH. Expression of the p53 transgene in the normal ileum was twice as high as in the colon. Treatment with DMH significantly decreased the expression of the p53 transgene both in the ileum (from 18% to 100%) and in the colon (from 10% to 52%). Vaccination of mice protected at least in part such a decrease. The most effective results were found after exposure of mice to polyclonal H-p53 and to a lesser extent to anti-p53 IgG. No difference was found in the effects of antibodies on the small and large intestines. We concluded that polyclonal antibodies were more effective than monoclonal ones in protection against anti-p53 action of DMH. The observation of these effects may make it possible to explain the higher antitumor activity of polyclonal antibodies.

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.

The immune response of rat spleen to dietary fibers and to low doses of carcinogen: morphometric and immunohistochemical studies

The effects of high-fiber diets on anticancer immune response are often masked by the effects of high-dose carcinogens. Using low levels of carcinogen the splenic immune response can be evaluated. Colon tumors were induced in rats with low doses of 1, 2-dimethylhydrazine, in the following experimental groups: rats fed with low fiber diet without exposure to carcinogen; rats exposed to the carcinogen and fed with low-fiber diet; rats exposed to carcinogen, and maintained on high-fiber diets, and did not develop tumors; and rats that developed tumors after exposure to carcinogen and maintenance on either low-fiber or high-fiber diets. After 24 weeks their spleens were studied immunohistochemically and morphometrically. In tumor-free rats, low doses of carcinogen caused significant response of the lymphoid system. This was manifested in the intensive blast transformation and in an increase in the number of dendritic cells and macrophages in different structures of the spleen. Dietary fibers activated these processes: the number of Ki-67 positive cells, macrophages and plasma cells increased significantly in the red pulp. A positive correlation was found between the effects of the carcinogen and proliferation of lymphocytes in the white pulp, and to lesser degree between high-fiber diets and lymphocytic abundance in the red pulp. The number of splenic apoptotic lymphocytes decreased in rats exposed to carcinogen. In tumor-bearing rats, immune insufficiency of the splenic responses was seen in the significant decrease of the areas of the mantle layer and the periarterial sheaths, as result of the decreased number of lymphocytes. Dietary fibers reduced the degree of this insufficiency. Even low doses of carcinogen cause a significant splenic immune response. This reaction has a compensatory character with macrophages, B and T cells participating. Addition of any high-fiber diet after the exposure to carcinogen activated the lymphocyte proliferation in the spleen.

Tumor-preventive effects of the soluble p53 antigen on chemically-induced skin cancer in mice

BACKGROUND

The tumor-suppressive effects of the rat soluble p53 antigen on chemically induced skin cancer in mice and the role of the spleen in the immune response to a carcinogen and vaccination were studied.

METHODS

Skin cancer was induced by 9,10-dimethyl-1,2-benzanthracene (DMBA). Vaccination was initiated by injection of liposomes with the soluble p53 antigen (10-12 micrograms/mouse) while boosters were with the p53 mixed with Freund's incomplete adjuvant (two injections). Four months later, the spleen and tumors were removed and examined morphometrically (determination of areas of different spleen's zones) and immunohistochemically (determination of number of B lymphocytes and macrophages, apoptotic index). The following groups of mice were studied: A) control non treated mice; Bl) tumor-free mice treated with a carcinogen; B2) tumor-bearing mice; Cl) tumor-free vaccinated mice exposed to a carcinogen; C2) tumor-bearing vaccinated mice.

RESULTS

Mice exposed to a carcinogen, which were tumor-free, displayed high proliferative activity of the spleenic lymphoid constitutes such as B lymphocytes and macrophages. This was reflected in the remarkable transformation of B lymphocytes in lymphoblasts (blast transformation) and an increase in the area of germinal centers, compared to untreated controls. In tumor-bearing non vaccinated mice, significantly more spleenic apoptotic cells were found than in their tumor-free counterparts. Shrinkage of the mantle layer and a decrease in cellular density of follicles were seen in all carcinogen-treated mice, reflecting the reduced total production of lymphoid cells, and thus the insufficiency of the immune reaction of animals to a carcinogen. A sharp decrease in the apoptotic index in the spleen of tumor-free mice may reflect an inhibition of apoptotic activity of the spleen by a carcinogen. Vaccination with the soluble p53 protein decreased the incidence of tumors and their size, significantly increased the apoptotic index within tumors, and reversed the splenic parameters of immune insufficiency.

CONCLUSIONS

The immune system is active during tumorigenesis. Vaccination with the soluble p53 antigen had positive tumor-suppressive effects. The findings may facilitate the development of vaccines for the prevention of recurrent cancers in humans.

Effects of dietary fiber on the rat intestinal mucosa exposed to low doses of a carcinogen

BACKGROUND

Changes in morphological and immunohistochemical parameters were studied in the rat intestinal mucosa exposed to low doses of a carcinogen and administered with dietary fibers.

METHODS

Tumors were induced by five subcutaneous injections of 1,2-dimethylhydrazine, 10 mg/kg rat, once a week. Rats were fed a semi-synthetic fiber-free diet (control) or a high-fiber diets (15%) derived from cellulose, tomato peels or white grape. The rats were sacrificed 24 weeks after the first carcinogen's injection. The ileum, colon and tumors were removed for the study. Areas of the mucosal stroma and of lymph infiltrations, and mitotic index were studied along with morphological parameters. Immunohistochemical parameters included determination of Ki-67 proliferating protein and apoptotic index.

RESULTS

Areas of the stroma in colon tumors increased in rats fed tomato peels. Changes in areas of lymphoid infiltrates were related to the type of diet and tumor presence. Lymphoid infiltrations were found to be highly developed in the colon area close to tumors, especially in rats fed the white-grape diet. Mitotic index and Ki-67 protein increased significantly in the colon area close to a tumor and in tumors themselves without any relation to the fiber varieties consumed. Changes in the rate of apoptosis were not related to the preventive effect of diets: apoptotic index was high in tumors obtained from rats fed the high-cellulose diet with high tumor-preventive effects and also from rats fed the high-tomato-peel diet with low tumor-preventive effects.

CONCLUSIONS

No morphological changes were found in the ileum of rats exposed to a carcinogen and fed different dietary fibers. In the colon, a carcinogen even in low concentrations inhibited the lymphoid system in the mucosa located far from the tumor or close to the tumor. An increase in the proliferation rate in the colon close to the tumor may reflect the development of precanceromatous processes or may be related to the effect of growth factors expressed by tumor cells. Finding adenoma-like dysplasia near tumors may be possible in early stages of the development of new tumors. In addition, activation of the lymphoid system of the colon following consumption to specific dietary fiber may be a mechanism by which fiber protect against cancer.

Immune response of rat spleen cells to a carcinogen and to vaccination with anti-p53 polyclonal antibodies

BACKGROUND

The tumor-suppressive effects of rabbit anti-p53 antibodies on chemically induced rat colon cancer were demonstrated previously (Cancer J, 10:116-120, 1997).

METHODS

In this communication, the spleen's role in the immune response of rats to cancer and vaccination was evaluated histologically and immunohistochemically. The following groups of rats were studied: a) control non treated rats; b) tumor-free non vaccinated rats treated with a carcinogen; c) tumor-bearing non vaccinated rats; d) tumor-free vaccinated rats exposed to a carcinogen; e) tumor-bearing vaccinated rats.

RESULTS

Exposure to a carcinogen (group 2) caused the appearance of the proliferative and apoptotic changes associated with immune response. They included abundant blast transformation of CD20-positive B lymphocytes, expansion of germinal centers and of periarterial sheaths (CD3-positive T cells), an increase in the number of plasma cells, mitotic and apoptotic cells in the follicles, and in CD25 IL2-depending T cells. The presence of colon tumors (group 3) caused insufficiency of the splenic lymphoid system: blast transformation was weaker, the white pulp area decreased and its devastation was reflected in fewer lymphoid cells. There were less plasma cells in the red pulp, while the number of dendritic cells, CD25+ T cells, macrophages and neutrophils increased sharply, suggesting a compensatory reaction to the severe antigenic effects. Similar, but stronger changes, occurred in tumor-free vaccinated rats (group 4). In tumor-bearing vaccinated rats (group 5), the rate of proliferation change was higher than in group 3, probably as a result of a weaker splenic insufficiency. A strong correlation was found between the number of mitotic, apoptotic or dendritic cells, tumorigenesis and vaccination.

CONCLUSIONS

A sharp increase in the number of dendritic cells in vaccinated tumor-bearing rats suggests that these cells participate in the host's reaction to tumorigenesis. We conclude that vaccination with anti-p53 polyclonal antibodies activates lymph components of the spleen.

Role of apoptosis, proliferating cell nuclear antigen and p53 protein in the immune response of rat colon cells to cancer and vaccination with anti-p53 polyclonal antibodies

BACKGROUND

Previously it was shown that rabbit anti-p53 antibodies can exert tumor-suppressive effects on chemically induced rat colon cancer (Cancer J, 10:116-120, 1997). This work examines the role of some components of the immune system in the response of the rat colon cells to treatment with a carcinogen and anti-p53 antibodies.

METHODS

The following groups of rats were studied: a) control non treated rats; b) tumor-free non vaccinated rats treated with a carcinogen; c) tumor-bearing non vaccinated rats; d) tumor-free vaccinated rats exposed to a carcinogen; e) tumor-bearing vaccinated rats. The manifestation of apoptosis, proliferating cell nuclear antigen (PCNA), mitotic index, T lymphocytes and p53 protein was compared between the different groups of rats.

RESULTS

The apoptotic index and the number of p53-positive cells and T lymphocytes were significantly higher in colon adenocarcinomas obtained from vaccinated rats than in unvaccinated rats. PCNA was lower in tumors from the vaccinated rats, whereas the proliferating cell index was not different between the both groups of rats. An inverse relationship was seen between apoptosis and most other parameters studied. The inverse correlation found between apoptosis and p53 protein in this study demonstrated that apoptosis acts as a p53-independent parameter in chemically induced rat colon cancer.

CONCLUSIONS

Our findings demonstrated that vaccination significantly activated apoptosis in both types of colon tissue, and induced synthesis of p53 protein in tumor tissue. Vaccination with anti-p53 polyclonal antibodies seemed to activate the immune system and to stimulate some of its cellular components responsible for tumor suppression.

Role of apoptosis, proliferating cell nuclear antigen and p53 protein in chemically induced colon cancer in rats fed corncob fiber treated with the fungus Pleurotus ostreatus

The role of apoptosis, proliferative cell nuclear antigen (PCNA) and p53 protein in the preventive effects of dietary fiber treated with the fungus Pleurotus ostreatus on rat-colon tumorigenesis was studied. Tumors were induced by five subcutaneous injections of 1,2-dimethylhydrazine (DMH), 20 mg/kg rat, once a week. Rats were fed a semi-synthetic fiberfree diet (control) or a high-fiber diet (15%) derived from corncob treated or non-treated with the fungus. The rats we sacrificed 24 weeks after the first carcinogenic injection. The fungus treated corn-cob significantly decreased tumor incidence (to 26%) as compared to 44% and 57% in the other dietary groups. The apoptotic index (AI) significantly decreased in malignant tissue as compared to non-tumorous tissue. PCNA and cytoplasmic content of p53 protein exhibited an increasing trend in malignant tissue as compared to benign tissue (at 15% and 18%, respectively). The fungus-treated corncob significantly increased the content of p53 in the cell cytoplasm (to 33%) and its serum levels in tumor-bearing rats (to 38%). The cellular concentration of PCNA decreased to 61% in tumors obtained from rats fed the fungus-treated corncob as compared to controls. A high positive correlation was found between tumor grade and p53 protein in the serum (r = 0.97) or in the cell cytoplasm (r = 0.77) and between tumor grade and PCNA (r = 0.81). An inverse relationship was found between tumor grade and AI (r = -0.63). We found that 15% of corncob fiber alone seems not to be enough to prevent chemically induced tumorigenesis. The corncob fiber (15%) treated with the fungus had a significant protective effect against DMH-induced rat colon cancer, even at 15% and this effect was accompanied by the activation of some cellular mechanisms such as apoptosis, PCNA and p53 protein activation. Incubation of corncob with the fungus Pleurotus os, increased the dietary fiber content up to 78%. Thus corncob inhibits colon cancer development, and, therefore, may considered of potential use to the public.

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.

HPLC determination of serum levels of soluble p53 antigen as a new method for colon cancer detection, and its clinical implication

Previously, we have described a new modification of affinity chromatography columns for isolation of the cytoplasmic, soluble form of tumor-associated antigens (TAA) from the serum of colon cancer patients (Oncol Rep 2: 679-683, 1995). In this communication, we have shown that the main proteins of these TAA were p64 and p53. The correlation coefficient between each of these proteins and the total amount of TAA or total serum protein ranged from 0.55 to 0.93. The serum level of p53 antigen was shown to be related to the tumorigenicity: the correlation and regression coefficients between the serum level of p53 protein and the progress in colon cancer were 0.48 and 0.88, respectively, p<0.001. Therefore, the determination of serum concentration of this protein can serve as a screening tool for cancer detection. The serum level of p53 protein ranges between 0.24 to 0.94 mg/ml in patients with non cancer diseases, and between 1.0 to 2.0 mg/ml in patients with polyposis and in a high risk group, respectively, increases over 2.0 mg/ml in primary colon cancer patients and up to 5.0 mg/ml in cancer patients with metastases. The sensitivity and specificity of our method achieved 92% and 96%, respectively, and accuracy 88%. The presence of p53 protein in the cytoplasm of cells from patients with non cancer diseases may explain why p53 antigen is presented in their sera. Our method can be useful to detect cancer development either as a primary illness or as a recurrent disorder. It is possible to follow up patients with chronic diseases and to detect transformation of these diseases into cancer, or to follow up former cancer patients in order to detect as early as possible incidence of recurrent cancer. It should also be emphasized that our method allows the detection of patients with polyposis or those of high risk groups who exhibit a tendency to develop colon cancer.

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.

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.

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.

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.

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.

Central serous retinopathy (choroidopathy) in pilots

The clinical charts of pilots in the Israeli Airforce were reviewed retrospectively for evidence of central serous retinopathy (CSR). There were 14 pilots with documented CSR identified, with an incidence of 1.3 per 1000 per year. Of 6 pilots who had recurrent attacks, 5 had a decrease of visual acuity during the initial attack to at least 20/30 in the affected eye. On the other hand, in those with visual acuity no worse than 20/25, only 1 of 7 had recurrent attacks (p less than 0.05). We conclude that CSR is a common condition in pilots, and that visual acuity during the initial attack can predict those who will have recurrent disease.