Does adding intravenous fentanyl to caudal block in children enhance the efficacy of multimodal analgesia as reflected in the plasma level of catecholamines?

BACKGROUND AND OBJECTIVE: Several studies showed that single analgesic modality management can attenuate perioperative stress, but little is known about the effect of multimodal analgesia on catecholamine responses to surgical trauma in children. METHODS: Fifty children (American Society of Anesthesiologists Grade I or II) were randomly allocated to one of two groups: one received general anaesthesia and a caudal block (control group), and one group was given general anaesthesia, caudal block and intravenous (i.v.) fentanyl 2 microg kg(-1) (fentanyl group). Plasma epinephrine and norepinephrine concentrations were measured three times during the perioperative period: at induction time (T(0)), at the end of surgery (T(1)) and when the children were fully awake in the postanaesthesia care unit (T(2)). RESULTS: There was a significant reduction in the catecholamine levels in the two groups when (T(1)) and (T(2)) were compared with T(0). When plasma epinephrine levels (at T(0), T(1) and T(2)) between the two groups were compared, a statistically significant reduction at T(2) was obtained in the fentanyl group, when compared with the control group. However, plasma norepinephrine levels showed no statistically significant difference between the two groups (at T(0), T(1) and T(2)). CONCLUSION: These findings suggest that the multimodal analgesic approach of adding i.v. low-dose fentanyl to a caudal block may decrease the plasma epinephrine release in children undergoing inguinal herniotomy.

Increased C-reactive protein levels in the polycystic ovary syndrome: a marker of cardiovascular disease.

The polycystic ovary syndrome (PCOS), one of the most common reproductive abnormalities, shares some components of the metabolic cardiovascular syndrome. Therefore, PCOS patients may represent the largest group of women at high risk for the development of early-onset cardiovascular disease (CVD) and/or diabetes. C-reactive protein (CRP) is a strong independent predictor of future CVD and/or stroke. Only one small published study has looked for such an association (17 PCOS patients vs. 15 controls). The objective of this study was to compare the levels of CRP and other risk factors of CVD in a large group of PCOS patients and controls. CRP measurements were undertaken in 116 PCOS patients and 94 body mass index-matched controls with regular menstrual cycles. Whereas 36.8% of the PCOS patients had CRP levels above 5 mg/liter, only 9.6% of the controls exhibited high CRP levels (P < 0.001). The mean +/- SD was 5.46 +/- 7.0 in the PCOS group vs. 2.04 +/- 1.9 mg/liter in the control (P < 0.001). The body mass index, white blood cell count, TSH, glucose, cholesterol, and homocysteine levels were not significantly different between the two groups. CRP levels are elevated in patients with PCOS and may be a marker of early cardiovascular risk in these patients. High CRP levels may explain why some PCOS women may possibly be at an increased risk for the development of early-onset CVD. Consequently, whether treatment regimens directed toward lowering CVD risk factors should be more aggressive for those PCOS women with increased CRP levels, awaits further clinical experience.

Association between fasting glucose and C-reactive protein in middle-aged subjects.

AIMS: C-reactive protein (CRP), a marker of subclinical inflammation, predicts the occurrence of coronary heart disease in healthy subjects. Hyperglycaemia is known to stimulate the release of inflammatory cytokines from various cell types and can lead to the induction and secretion of acute-phase reactants by adipocytes. The aim of the present study was to determine the relation between glycaemic status and CRP in healthy subjects. METHODS: We studied the relation of high-sensitivity CRP to fasting glucose and other components of the metabolic syndrome in a population-based cross-sectional study (n = 1000; age 50 +/- 9 years). RESULTS: Plasma CRP levels increased continuously from the lowest quartile of normal fasting glucose level to impaired fasting glucose and to diabetes (ln CRP 0.47 +/- 0.09, 0.95 +/- 0.12, and 1.11 +/- 0.13, respectively; Ptrend < 0.0001). Increasing CRP with higher fasting glucose levels was apparent even among subjects with fasting glucose in the normal range (Ptrend = 0.039), and subjects with fasting glucose level in the upper quartile of normal fasting glucose had higher CRP levels compared with subjects in the lower quartile (P = 0.035). There was a positive crude correlation between CRP and smoking, post-menopausal hormone use, body mass index, fasting glucose, triglycerides, hypertension, and uric acid (r = 0.11-0.36, P = 0.002-0.0001). A negative correlation was found between CRP and HDL-cholesterol (r = 0.12, P < 0.0001) and physical activity (r = 0.11, P = 0.002). After adjustment for potential confounders in a stepwise multivariate linear regression model, fasting glucose remained significantly and independently related to CRP levels (correlation coefficient 0.06; 95% confidence interval 0.014-0.11, P = 0.011). CONCLUSIONS: Fasting glucose is significantly and positively associated with plasma CRP in middle-aged subjects. CRP levels increase continuously across the spectrum of fasting glucose, beginning in the lowest quartile of normal fasting glucose. This finding suggests that a proinflammatory effect may contribute to the adverse cardiovascular outcome associated with diabetes, impaired fasting glucose, and increasing glucose levels within the normal range.

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.

Does the addition of fentanyl to bupivacaine in caudal epidural block have an effect on the plasma level of catecholamines in children?

We evaluated the effect of adding fentanyl to bupivacaine, compared with bupivacaine alone, on the stress response. The effect was evaluated by determining blood levels of epinephrine (E) and norepinephrine (NE) in pediatric patients receiving caudal epidural blocks. Sixty children, 1-8 yr of age, scheduled for elective herniorrhaphy, were randomly allocated to two groups of 30 patients each. Group A received inhaled anesthesia and caudal epidural block with bupivacaine 0.25% alone, 1.0 mL/kg. Group B received identical anesthesia; however, fentanyl 1 microg/kg was added to the bupivacaine in the caudal block. Blood samples for E and NE plasma levels were drawn at induction time (H(0)), at the end of surgery (H(1)), and in the postanesthesia care unit (H(2)). In both groups, there was a significant decrease in the E and NE plasma levels, when comparing H(1) and H(2) with H(0) within the same group (P < 0.001). There were no significant differences in the E and NE plasma levels between the two groups at H(0), H(1), and H(2) (P = 0.5, P = 0.12, P = 0.5, respectively). Pain scores (modified Children's Hospital of Eastern Ontario Pain Score) were also similar in both groups (P = 0. 19). This study suggests that adding fentanyl 1 microg/kg to bupivacaine in the caudal epidural block in children does not influence plasma levels of E and NE, nor does it improve the analgesic intensity of the caudal block.

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.

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.

Neuroactive steroids: their mechanism of action and their function in the stress response.

Steroids are usually identified as genomic regulators, yet recently a body of evidence has accumulated demonstrating specific plasma membrane effects, as well as coordinative effects, of some steroids on both membrane and intracellular receptors. The resulting rapid (<1 min) modulation of cellular activity has strongly suggested a non-genomic, and possibly modulatory, role for certain steroid compounds, and dramatic effects on membranes of excitable as well as other tissues have been demonstrated. Steroid synthesis and metabolism have been shown to exist in the CNS, and the effects have been seen in both the central and peripheral nervous systems. The major groups of neuroactive steroids, and their metabolites, have been progesterone, deoxycorticosterone, and some androgens, notably dihydroxyepiandrosterone (DHEA). These compounds show increased concentrations both in blood and in the brain following stress and they have also been associated with anxiolytic effects and antiepileptic activity. In the periphery, some of these compounds show remarkable inhibitory effects on the secretion of catecholamines and other neurotransmitters. The mechanism for the majority of the effects of these steroids is via their effect on receptor-mediated binding to ligand-gated ion channels. Activation of the GABAA receptor complex, resulting in the opening of its central chloride channel, is the major target of the neuroactive steroids, resulting in re-polarization of the plasma membrane and inhibition of further neuronal firing. The anxiolytic, anti-convulsant and sedative-hypnotic actions of these neuroactive steroids have resulted in their being used as therapeutic agents for the treatment of anxiety, epilepsy, insomnia, and possibly for the alteration of pain thresholds.

Transcription of actin, cyclophilin and glyceraldehyde phosphate dehydrogenase genes: tissue- and treatment-specificity.

Studies involving RNA transcription, in varying biological systems, usually necessitate a term of transcriptional reference. Traditionally, the transcription of the gene of interest was compared to a constitutively expressed 'control' gene. Run-on transcription analysis was undertaken to evaluate and compare the transcription of three frequently used 'control genes' (beta-actin, cyclophilin and glyceraldehyde-3-phosphate dehydrogenase), in nine rat tissues. Similarities, but also clear and highly significant differences, were found in the transcription profiles of these three genes. There was significantly greater transcription for uterine glyceraldehyde-phosphate dehydrogenase compared to all other tissues tested, while both cyclophilin and glyceraldehyde-phosphate dehydrogenase were significantly elevated in the adrenal cortex. Upon cholinergic agonist treatment, both beta-actin and glyceraldehyde-phosphate dehydrogenase RNA expression were greatly induced in the adrenal medulla (41- and 94-fold, respectively), while cyclophilin transcription was not altered. In another treatment paradigm, surgical ovariectomy, only uterine glyceraldehyde-phosphate dehydrogenase transcription was significantly reduced. While, all three of these genes are assumed to be constitutively expressed throughout the body and hence used as normalization controls, the current study questions these accepted terms of reference. As cyclophilin transcription was not affected in both treatment paradigms, it should be considered more seriously as a RNA normalization control.

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.

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.

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.

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.

Effect of caudal block on the plasma adrenaline and noradrenaline concentrations in paediatric patients undergoing ilioinguinal herniorrhaphy.

This study compared the effect of two anaesthetic techniques on the catecholamine levels in children undergoing ilioinguinal herniorrhaphy. Forty male paediatric patients ASA class I were allocated randomly to one of two groups: the control group (n = 20) received general anaesthesia including intravenous fentanyl; and the caudal group (n = 20) received caudal anaesthesia with bupivacaine 0.25% 1 mL kg-1 combined with general anaesthesia but without opioids. Plasma adrenaline and noradrenaline concentrations were measured at induction, at the end of surgery and in the post-anaesthesia care unit (PACU). In the caudal group, there were significant decreases in the adrenaline and noradrenaline concentrations at the end of surgery and in the PACU compared with baseline concentrations. In the control group, there was a significant increase in PACU concentrations of adrenaline and noradrenaline compared with baseline concentrations. These findings suggest that the addition of a caudal block to general anaesthesia in children undergoing ilioinguinal herniorrhaphy decreases significantly the neurohormonal responses to surgery.

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.

Specificity of polyclonal anti-p53 IgG for isolation of the soluble p53 antigen from human serum.

The possibility to use anti-p53 IgG for isolation of the soluble p53 antigen as a serological tumor marker has been shown in our previous studies. In order to prove the specificity of such IgG, we compared the effectiveness of columns with anti-p53 IgG and IgG isolated from non-treated rabbits (regular IgG). The gel fiberglass (GFG) columns for affinity chromatography were prepared separately with both types of IgG. The same serum was percolated simultaneously through both columns and the results of elution were compared. The total concentration of tumor-associated antigens (TAA) eluted from the serum of cancer patients was similar in both TAA mixtures isolated either with anti-p53 IgG or with the regular IgG. Differences are manifest in the content of total proteins and amount of each eluted protein: a mixture eluted with the regular IgG contains several proteins whereas the anti-p53 IgG isolated only two proteins, p64 and p53. The amount of the soluble p53 antigen isolated from the cancer serum was significantly higher when it was isolated with anti-p53 IgG. The method developed in our laboratory was shown to be highly specific both to isolate proteins related to cancer (p53) and non-cancer disorders (p64). Data presented in this report show that such specificity can be achieved only if the anti-p53 IgG is used: the regular IgG obtained from non-treated animals isolate many proteins among which the concentration of specific p53 protein is lost.

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.

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.

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.