The Differential Regulation of Human Telomerase Reverse Transcriptase and Vascular Endothelial Growth Factor May Contribute to the Clinically More Aggressive Behavior of P63-Positive Breast Carcinomas

p63, a p53 homologue, is a myoepithelial cell marker in the normal mammary gland but p63-positive neoplastic cells may be found in up to 11% of invasive breast carcinomas. This study aims to verify the relationship between p63 expression and several clinicopathological features and tumor markers of clinical significance in breast pathology including key regulators of the cell cycle, oncogenes, apoptosis-related proteins, metalloproteinases and their inhibitors. Immunohistochemistry with 27 primary antibodies was performed in 100 formalin-fixed paraffin-embedded samples of invasive ductal carcinomas. p63-positive cells were found in 16% of carcinomas. p63-positive carcinomas were poorly differentiated, hormone receptor-negative neoplasms with a high proliferation rate. p63 also correlated with advanced pathological stage, tumor size, and the expression of human telomerase reverse transcriptase (hTERT), tissue inhibitor of matrix metalloproteinase 1 (TIMP1) and vascular endothelial growth factor (VEGF). The expression of TIMP1 suggests that the anti-proteolytic stimuli may be preponderant in p63-positive carcinomas. hTERT activity is associated with nodal metastases and cellular proliferation. VEGF regulates angiogenesis, which is also a fundamental event in the process of tumor growth and metastatic dissemination. Thus, the differential regulation of hTERT and VEGF in p63-positive breast carcinomas may contribute to the clinically more aggressive behavior of these neoplasms.

The Expression of p63 and Cytokeratin 5 in Mixed Tumors of the Canine Mammary Gland Provides New Insights into the Histogenesis of These Neoplasms

Cytokeratin 5 and p63 have been described as basal and myoepithelial cell markers in human breast. Mixed tumors of the canine mammary gland have been associated with a myoepithelial origin. Cytokeratin 5 expression has not been evaluated in these tumors. We investigated the relation between cytokeratin 5 and p63 double-immunohistochemical expression in 23 mixed tumors of the canine mammary gland (10 benign mixed tumors and 13 carcinomas arising from benign mixed tumors) and their origin. Cytokeratin 5 and p63 co-expression was observed in myoepithelial cells of benign mixed tumors, as well as in squamous differentiation of carcinoma arising from benign mixed tumors. Though a few interstitial spindle cells of the mesenchymal components expressed both p63 and cytokeratin 5, the basal epithelial cells were labeled only by cytokeratin 5. The co-expression of p63 and cytokeratin 5 in myoepithelial cells and squamous differentiation suggest that, like in human breast, cytokeratin 5 can also be considered a myoepithelial- and squamous-cell differentiating marker in canine tumors. The presence of some interstitial spindle cells stained for p63 and cytokeratin 5 might be associated with a myoepithelial origin of the mesenchymal component of mixed tumors of the canine mammary gland. Moreover, contrary to p63, basal epithelial cells were labeled by cytokeratin 5, indicating that cytokeratin 5 may not represent an exclusive myoepithelial cell marker but also a basal epithelial cell marker in canine mixed tumors. According to these data, basal epithelial cells may be related to the origin of the epithelial component of mixed tumors of the canine mammary gland.

Liver HLA-G expression is associated with multiple clinical and histopathological forms of chronic hepatitis B virus infection

As the mechanisms leading to the persistence of hepatitis B virus (HBV) infection are poorly understood and as the histocompatibility leucocyte antigen (HLA)-G is well described as a tolerogenic molecule, we evaluated HLA-G expression in 74 specimens of HBV liver biopsies and in 10 specimens obtained from previously healthy cadaver liver donors. HBV specimens were reviewed and classified by the METAVIR score, and HLA-G expression was assessed by immunohistochemistry. No HLA-G expression was observed in control hepatocytes. In contrast, 57 (77%) of 74 HBV specimens showed soluble and membrane-bound HLA-G expression in hepatocytes, biliary epithelial cells or both. No associations between the intensity of HLA-G expression and patient age or gender, HBeAg status, severity of liver fibrosis, and grade of histological findings were observed. Although significance was not reached (P = 0.180), patients exhibiting HLA-G expression presented a higher median HBV DNA viral load (10⁵ copies/mL) than those who did not express HLA-G (10(3.7) copies/mL). These results indicate that HLA-G is expressed in most cases of chronic HBV infection in all stages and may play a role in the persistency of HBV infection.

The use of light-emitting diodes to stimulate mitochondrial function and liver regeneration of partially hepatectomized rats

The biostimulating effect of laser radiation has been observed in many areas of Medicine. However, there are still several questions to be answered, among them the importance of light coherence in the stimulatory process. In the present study, we used light-emitting diodes (LED) to promote the stimulation of liver regeneration after partial hepatectomy in rats. Fourteen male Wistar rats weighing 200-250 g were submitted to partial hepatectomy (70%) followed by LED light irradiation (630 nm) of the remaining part of the liver at two doses, i.e., 10 (N = 7) and 140 (N = 7) J/cm(2). A group irradiated with laser, 590 nm (N = 7, 15 J/cm(2)) was performed for the study of proliferating cell nuclear antigen-labeling index. Data are reported as mean +/- SEM. Statistical comparisons of the groups were performed by analysis of variance for parametric measurements followed by the Bonferroni post-test, with the level of significance set at P < 0.05. Respiratory mitochondrial activity was increased in the irradiated groups (states 3 and 4; P < 0.05), with better results for the group exposed to the lower LED dose (10 J/cm(2)). The proliferating cell nuclear antigen-labeling index, by immunohistochemical staining, was similar for both LED-exposed groups (P > 0.05) and higher than for the control group (P < 0.05). The cell proliferation index obtained with LED and laser were similar (P > 0.05). In conclusion, the present results suggest that LED irradiation promotes biological stimulatory effects during the early stage of liver regeneration and that LED is as effective as laser light, independent of the coherence, divergence and cromaticity.

Effect of hyperbaric oxygen on liver regeneration in a rat model

Hyperbaric oxygen therapy is a treatment that has been gradually implemented for the treatment of several pathologic conditions. The present study evaluated the effect of hyperbaric oxygen therapy for hepatic regeneration and its relationship to mitochondrial function. Male Wistar rats underwent partial hepatectomy (70%) and subsequently underwent two sessions of hyperbaric oxygen (90 minutes each, at a pressure of 2 ATA). The animals were sacrificed at 24 and 48 hours after surgery. Hepatic regeneration was evaluated by the dry weight of the remaining liver, the hepatic regeneration rate, the hepatic DNA content, and the hepatocyte proliferation rate using the "proliferating cell nuclear antigen" (PCNA) content. Function of the mitochondria was evaluated by its oxygen consumption during respiratory states 3 and 4, its respiratory control ratio (RCR), its membrane potential, as well as its osmotic swelling. We also measured serum levels of aminotransferases. The results revealed an increased dry weight of the remaining liver, regeneration rate, and DNA content at 24 and 48 hours after hepatectomy. The hepatocyte proliferation rate was significantly higher among animals treated with hyperbaric oxygen therapy at 48 hours after surgery. There was no significant difference in aminotransferase levels. Mitochondrial respiration revealed reduced oxygen consumption in state 3 after 48 hours. These results demonstrated that hyperbaric oxygen stimulates hepatic regeneration at 24 and 48 hours after 70% hepatectomy. The effect of hyperbaric oxygen on hepatic tissue occurs without tissue damage and protects mitochondria after 48 hours.

Therapeutic Effect of Hyperbaric Oxygen in Hepatic Artery Thrombosis and Functional Cholestasis After Orthotopic Liver Transplantation

Among the postoperative complications, hepatic artery thrombosis can occur in up to 10% of adult orthotopic liver transplants and intervention is indicated when this occurs within 30 days by retransplantation. Primary graft dysfunction, which can occur in up to 30% of the cases and is another potential complication, although reversible, has a relatively high mortality rate. Hyperbaric therapy, an efficient mode of tissue oxygenation, is being used in an increasing number of clinical situations. We report here two cases where hyperbaric oxygen therapy greatly benefited patients with complications after orthotopic liver transplantation: one with hepatic artery thrombosis and the other with primary graft dysfunction. Both patients showed rapid clinical recovery with gradual reduction of liver and canalicular enzymes soon after commencing hyperbaric oxygen therapy.

Expression of checkpoint kinase 2 in breast carcinomas: correlation with key regulators of tumor cell proliferation, angiogenesis, and survival

Checkpoint kinase 2 (Chk2) is a cell-cycle-checkpoint kinase that may act as a tumor suppressor gene due to its important role in DNA damage signaling and cell cycle regulation. The role of Chk2 expression in mammary tumorigenesis, however, is still poorly understood. This study was designed to assess the relationship between the expression of Chk2 and well-established prognostic factors, including disease-free-survival and overall survival; and several regulators of cell proliferation and invasiveness in breast carcinomas, including oncogenes, tumor suppressor genes, apoptosis-related proteins, and angiogenesis-related markers. Immunohistochemistry with 27 primary antibodies was performed in 100 formalin-fixed paraffin-embedded samples of not otherwise specified invasive ductal carcinomas. Clinical data were retrieved from medical files. In normal mammary parenchyma adjacent to the tumors Chk2 stained the nuclei of epithelial cells. Downexpression of Chk2 protein was observed in 23 carcinomas and correlated with advanced disease. Among the regulators of tumor cell proliferation and invasiveness analyzed, the downexpression of Chk2 correlated only with reduced expression of p27 and telomerase. There was no difference between the overall survival and disease-free survival rates according to Chk2 status. In conclusion, Chk2 correlated with reduced expression of h-TERT and p27, but not with angiogenic factors. Chk2 expression also did not interfere in the outcome of the patients.

p63 correlates with both BRCA1 and cytokeratin 5 in invasive breast carcinomas: further evidence for the pathogenesis of the basal phenotype of breast cancer

AIMS

To study the expression of p63, cytokeratin (CK) 5 and CK8/18 in invasive ductal carcinomas and their relationship with BRCA1 and other pathological and immunohistochemical features of clinical significance.

METHODS AND RESULTS

Immunohistochemistry with the antibodies p63, CK5, CK8/18, BRCA1, oestrogen receptor, progesterone receptor, p53, c-erbB-2 and Ki67 was performed in 102 formalin-fixed paraffin-embedded samples of invasive ductal carcinomas. The CK5+ cases were submitted to a double-immunolabelling study with p63. There was a strong relationship between CK5 and p63 expression and both markers were associated with hormonal receptor-negative high-grade carcinomas with high proliferative rate. Furthermore, there was coexpression of CK5 and p63 in neoplastic cells, indicating that p63, like CK5, is a marker of the basal phenotype of breast cancer. There was a strong relationship between reduced expression of BRCA1 with both p63 and CK5 expression as well as an inverse correlation between p63 and CK8/18 expression, suggesting that loss of p63 expression is required for the transition between a basal to a luminal phenotype of breast carcinoma.

CONCLUSIONS

Since p63 is thought to be a marker of stem cells and may act as an oncogene, our data support the idea that BRCA1 acts as stem cell regulator.

Trends of accuracy of clinical diagnoses of the basic cause of death in a university hospital

AIMS

To determine the agreement between clinical and necropsy diagnoses of the basic cause of death, and to compare the results with those obtained in a previous study carried out at the same university hospital.

METHODS

In total, 4828 necropsies, performed between 1990 and 1995 in the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo, Brazil, were reviewed. Examinations were concluded at the macroscopic part of the necropsy in nearly 35% of the cases. Statistical analysis was carried out using the kappa coefficient comparing the clinical diagnosis and the diagnosis obtained after necropsy. The jackknife method was used to identify comparable kappa values for the comparison of the two periods.

RESULTS

Compared with the 1978-80 period, a significant increase in diagnostic agreement was seen for the group submitted to complete necropsy, whereas no similar increase was detected when only the macroscopic step was analysed.

CONCLUSIONS

There was a discrete tendency to an improved correlation between clinical and postmortem data stated by full necropsy analysis. The findings show that microscopic analysis remains important to confirm the cause of death in many cases. Diagnostic discrepancies remained high, and therefore complete necropsy continues to be an essential instrument for the assessment of clinical diagnosis.

Does the correlation between EBNA-1 and p63 expression in breast carcinomas provide a clue to tumorigenesis in Epstein-Barr virus-related breast malignancies?

Several investigators have identified Epstein-Barr virus (EBV) particles in breast carcinomas, a fact that supports a role for EBV in mammary tumorigenesis. The possible mechanism involved in this process is not clear. The present study was carried out in an attempt to determine whether there is a relationship between latent infection with EBV and p53 and p63 expression in breast carcinomas. Immunohistochemistry developed with 3.3-diaminobenzidine tetrahydrochloride was performed in 85 formalin-fixed paraffin-embedded breast carcinomas using anti-EBV EBNA-1, anti-p63, anti-p53, anti-estrogen receptor (ER) and anti-progesterone receptor (PR) antibodies. The cases were selected to represent each of the various histologic types: intraductal carcinoma (N=12), grade I invasive ductal carcinoma (N=15), grade II invasive ductal carcinoma (N=15), grade III invasive ductal carcinoma (N=15), tubular carcinoma (N=8), lobular carcinoma (N=10), and medullary carcinoma (N=10). The ductal breast carcinomas were graded I, II and III based on the Scarff-Bloom and Richardson grading system modified by Elston and Ellis. One slide containing at least 1000 neoplastic cells was examined in each case. ER, PR, p63, p53 and EBNA-1 were positive in 60, 40, 11.8, 21.2 and 37.6% of carcinomas, respectively. There was a correlation between EBNA-1 and p63 expression (P<0.001), but not between EBNA-1 and p53 (P=0.10). These data suggest a possible role for p63 in the mammary tumorigenesis associated with Epstein-Barr virus infection.

Expression of class ? glutathione-S-transferase in human liver and its association with hepatopathies

We studied the distribution of GSTM1 phenotypes in 611 individuals from an ethnically mixed sample of the Brazilian population who died from various causes. No influence of age, gender, or ethnicity was detected on the phenotypic distribution. In a sub-sample of 66 alcoholic individuals compared with 399 non-alcoholics there was almost a doubling of the odds ratio for GSTM1(0) individuals in the alcoholic category. The incidence of hepatopathies was higher in this group as well, and we observed a significant association of the null phenotype with cirrhosis. An excess of null phenotypes (374/611) was observed, and the allelic distribution was: GSTM1*A = 0.168, *B = 0.089, and *0 (null) = 0.743.

Spectral response for laser enhancement in hepatic regeneration for hepatectomized rats

BACKGROUND AND OBJECTIVES

The low intensity laser therapy (LILT) has been widely used in all medical fields due to its therapeutic effects in reparative process, pain relief, and biostimulation. Even though there is a therapeutic window of wavelengths for clinical application, little has been done concerning the frequency spectrum response to biological effects. In this work, we investigate the dependence of different wavelengths irradiation in the enhancement of the tissue regeneration after partial hepatectomy in Wistar rats.

STUDY DESIGN/MATERIALS AND METHODS

The proliferating cell nuclear antigen (PCNA) labeling index and the respiratory control (oxygen consumption in extracted mitochondria) were the tests used to evaluate the liver regeneration after laser irradiation with different wavelengths.

RESULTS AND CONCLUSIONS

The results show a correlated spectral response that can be explained based on the combined effect of light penetration on biological tissues and the biomolecular excitation efficiency for each wavelength used.

Topical application of benzalkonium chloride to the stomach serosa increases gastric emptying time, acid secretion, serum gastrin and size of the mucosa

AIM

In the present study we evaluated the effects of gastric myenteric denervation using benzalkonium chloride (BAC) on the time for gastric emptying, as well as gastric secretion, and mucosal epithelial cell size and population in rats.

METHODS AND RESULTS

Wistar rats were treated with topical serosal application of BAC to the stomach. Control animals received saline. Ninety days after surgery, gastric emptying time, gastric acid secretion and serum gastrin levels were studied. Next, the animals were sacrificed and the stomachs were removed, fixed in formalin and histologically processed for histomorphometry of the height, area and volume of the glandular portion, and volume and population of mucous, chief, parietal, G- and labelled cells. BAC animals showed a significant delay in gastric emptying and an increase in gastric acid secretion and serum gastrin levels. These animals also presented a significant reduction of myenteric neuron number, hypertrophy of parietal and chief cells, hyperplasia of G cells and an increase in the gastric mucosa area.

CONCLUSION

The absence of the myenteric plexus seems to protect the stomach from the hyperplastic effects of hypergastrinemia. Gastric food stasis may act as a factor triggering morphological and functional alterations of the gastric epithelium. Although gastric food stasis is a common finding in medical practice, its physiopathological consequences are poorly understood and have not been frequently discussed in the literature.

No reduction with ageing of the number of myenteric neurons in benzalkonium chloride treated rats

The number of myenteric neurons may be reduced by topical serosal application of benzalkonium chloride (BAC). We studied the effects of ageing in the population of neurons that survive after the application of BAC. Ten treated and ten control animals were killed at intervals of 2, 6, 12 and 18 months after the surgery. We performed myenteric neurons counting in serially cut histological preparations of the descending colon. The control animals revealed a continuous loss of myenteric neurons number with increasing of age. Interestingly, contrary to control animals, the BAC-treated rats presented no neuron loss with ageing at any experimental time. The reasons for their survival with ageing could be related to a neuroplasticity phenomenon.

Limitations of fine-needle aspiration cytology to diagnose metaplastic carcinoma of the breast

Metaplastic carcinoma is a very rare breast neoplasm that is often confused with benign and others malignant entities on both clinical and conventional histopathologic basis. Three cases of metaplastic carcinoma of breast are presented. The difficulties found on fine needle aspiration cytology and the limitations of this procedure are discussed as well the main features of this tumor.

Laser enhancement in hepatic regeneration for partially hepatectomized rats

BACKGROUND AND OBJECTIVE

The bio-stimulation effect of laser has been observed in many areas of Medicine. However, there are a few works which investigate its use for liver regeneration. Most of their results were inconclusive due to the use of high power lasers. This work was carried out to investigate the bio-stimulation effect of laser in liver regeneration using low power lasers.

STUDY DESIGN/MATERIALS AND METHODS

We used Wistar male rats, which were irradiated with laser light (wavelength 590 nm and intensity of 50 mW/cm(2)) for 5 minutes after 70% hepatectomy. The respiratory mitochondrial activity, the serum level of aminotransferase and the PCNA were measured.

RESULTS

Our results show a dramatic increase in the mitochondrial activity for the laser treated group at 24 hours after the hepatectomy.

CONCLUSIONS

We conclude that the laser promotes a bio-stimulation effect on the early stages of liver regeneration without any detectable damage of the cells.

EFEITOS DO PRÉ-CONDICIONAMENTO HEPÁTICO EM RATOS CIRRÓTICOS, SUBMETIDOS À ISQUEMIA E REPERFUSÃO HEPÁTICA RESULTADOS PRELIMINARES

Baseando-se nos efeitos estimuladores do metabolismo energético pelo pré-condicionamento isquêmico (PCI) no tecido hepático, estudou-se dois grupos de ratos cirróticos submetidos a isquemia de 20 min e reperfusão de 120 min, após o PCI ou não respectivamente, determinando assim o valor do seu uso no prolongamento da manobra de Pringle e na regeneração hepática na hepatectomia.

Angiotensin-converting enzyme inhibition by lisinopril enhances liver regeneration in rats

Bradykinin has been reported to act as a growth factor for fibroblasts, mesangial cells and keratinocytes. Recently, we reported that bradykinin augments liver regeneration after partial hepatectomy in rats. Angiotensin-converting enzyme (ACE) is also a powerful bradykinin-degrading enzyme. We have investigated the effect of ACE inhibition by lisinopril on liver regeneration after partial hepatectomy. Adult male Wistar rats underwent 70% partial hepatectomy (PH). The animals received lisinopril at a dose of 1 mg kg body weight(-1) day(-1), or saline solution, intraperitoneally, for 5 days before hepatectomy, and daily after surgery. Four to six animals from the lisinopril and saline groups were sacrificed at 12, 24, 36, 48, 72, and 120 h after PH. Liver regeneration was evaluated by immunohistochemical staining for proliferating cell nuclear antigen using the PC-10 monoclonal antibody. The value for the lisinopril-treated group was three-fold above the corresponding control at 12 h after PH (P<0.001), remaining elevated at approximately two-fold above control values at 24, 36, 48 (P<0.001), and at 72 h (P<0.01) after PH, but values did not reach statistical difference at 120 h after PH. Plasma ACE activity measured by radioenzymatic assay was significantly higher in the saline group than in the lisinopril-treated group (P<0.001), with 81% ACE inhibition. The present study shows that plasma ACE inhibition enhances liver regeneration after PH in rats. Since it was reported that bradykinin also augments liver regeneration after PH, this may explain the liver growth stimulating effect of ACE inhibitors.

EVOLUÇÃO DA FIBROSE BILIAR SECUNDÁRIA EM RATOS TRATADOS MEDIANTE DERIVAÇÃO BÍLIO-DUODENAL OU BÍLIO-JEJUNAL COM ALÇA DE ROUX MEDINDO 5, 10 E 15 CM

A modalidade de derivação bílio-digestiva empregada no tratamento da colestase extra-hepática crônica pode influenciar na reparação das lesões hepáticas. Avaliou-se o desempenho das derivações bílio-duodenal e bílio-jejunal em Y de Roux com alça exclusa de diferentes comprimentos na reparação das lesões morfológicas e funcionais do fígado de ratos com fibrose biliar secundária. Foram utilizados ratos Wistar, com 15 dias de obstrução biliar, alocados em 5 grupos de 6 animais. O grupo OB caracterizou as alterações da fibrose biliar. Os animais remanescentes foram tratados mediante derivação com o duodeno (grupo DBD), e com o jejuno, em alça exclusa de 5cm (grupo DBJ5), 10cm (grupo DBJ10) e 15cm (grupo DBJ15), sendo reavaliados 3 meses depois. Outros 6 animais foram submetidos à intervenção simulada e considerados grupo controle (IS). Todos animais foram submetidos à avaliação morfométrica do fígado, análise bioquímica do sangue e microbiológica da bile, estudo da função mitocondrial hepática e verificação do peso úmido do fígado e do baço. Na análise estatística adotou-se o nível de significância de 5%. Houve aumento significativo do peso estimado, em g/Kg de peso corporal, dos ductos biliares, da fibrose e dos hepatócitos nos animais do grupo OB (medianas de 1,30; 10,03 e 37,0) em relação aos animais controles (IS) (medianas de 0,03; zero e 29,37). Após tratamento, ocorreu regressão significativa do peso estimado dos ductos biliares e da fibrose, com valores medianos de 0,22 e 0,22 para o grupo DBD, 0,45 e 3,31 para o grupo DBJ5 e 0,22 e 5,0 para o grupo DBJ15. Houve regressão significativa do peso estimado dos hepatócitos apenas nos grupos derivados com o jejuno, com valores medianos de 31,93; 24,46 e 28,52. Ocorreu aumento significativo do peso úmido do fígado e do baço no grupo OB (medianas em g/Kg de peso corporal de 49,85 e 5,71) em relação ao grupo IS (30,0 e 3,04). Houve regressão significativa do peso do fígado em todos os tratamentos e do peso do baço nos animais tratados com derivação bílio-jejunal, (valores medianos de 35,59 e 2,53 para DBJ5, 37,54 e 2,82 para DBJ10 e 32,73 e 2,93 para DBJ15). Após o tratamento, surgiram infiltrado inflamatório misto, nos espaços portais, refluxo enterobiliar e contaminação bacteriana da bile. Houve aumento significativo no consumo de oxigênio pela mitocôndrias hepáticas nos estados 3 e 4 no grupo OB (medianas de 101,55 e 31,05 nanoátomos de O2/mgprot./min), em relação ao grupo IS (medianas de 57,22 e 15,51). Após o tratamento, normalizou-se o consumo energético apenas nos animais do grupo DBJ15 (medianas de 52,38 e 14,8). O desempenho da derivação bíilio-jejunal indica a importância de avaliar alternativas que possam minimizar o contato do conteúdo entérico com a via biliar.

Porphyria cutanea tarda in Brazilian patients: association with hemochromatosis C282Y mutation and hepatitis C virus infection

OBJECTIVE

Porphyria cutanea tarda (PCT) is commonly associated with iron overload and hepatitis C virus (HCV) infection. Association between hemochromatosis C282Y or H63D mutations and PCT has been observed, although not uniformly, and iron overload is also commonly found in chronic HCV hepatitis. The aim of the present study was to investigate the frequency of C282Y and H63D mutations and HCV infection in Brazilian patients with PCT and their relationship with iron overload.

METHODS

Twenty-three patients (19 men) aged 39.6 +/- 11.1 yr were studied. All had dermatological lesions of PCT and high levels of urinary uroporphyrin. HCV infection and iron overload were investigated. DNA samples were analyzed for the presence of HFE mutations.

RESULTS

The frequency of C282Y was significantly higher in PCT patients than in 278 healthy individuals (17.4% vs 4%, odds ratio = 5.1, 95% confidence interval 1.5-17.6, p = 0.02), whereas no difference was observed regarding the H63D mutation (30.4% vs 31%, odds ratio = 1, 95% confidence interval 0.4-2.4, p = 1). Biochemical tests in PCT patients showed iron overload with transferrin saturation = 47.3 +/- 20.7% and ferritin = 566.8 +/- 425 ng/ml. Fifteen of 23 (65.2%) patients had HCV infection and alcohol ingestion was observed in 17 of 23 (73.9%).

CONCLUSIONS

PCT patients exhibited evidence of iron overload, a high frequency of HCV, and an association with C282Y mutation. These data further support the notion that both acquired and inherited factors contribute to the occurrence of PCT, and indicate that screening for C282Y may be justified in PCT patients.

Effect of myenteric denervation on intestinal epithelium proliferation and migration of suckling and weanling rats

The effects of myenteric denervation on the cell kinetics of the intestinal epithelium of suckling and weanling rats were investigated. The myenteric plexus of an ileal segment was partially ablated by serosal application of benzalkonium chloride (BAC) in three groups of rats: those that underwent surgery at 13 days and were killed 15 (13/28-day-old) or 23 (13/36-day-old) days after treatment, and those that were operated at 21 days (21/36-day-old) and were killed 15 days after treatment. The extent of denervation was assessed in whole-mount preparations. The cell bodies of myenteric neurones were stained by NADH-diaphorase histochemical technique. Cell proliferation was estimated by the mitotic index (MI) and morphometric analysis of villus and crypt lengths using an image analysis system. Thickness of the muscle layers was also assessed by morphometry. Cell migration on the villi was estimated by the position of the leading labelled cell 24 h after tritiated thymidine injection. The number of neurones was reduced by around 80% in rats operated at 13 days, and reduced by 98% in those operated at 21 days. The thickness of the muscle layers was increased in all groups of treated animals. MI was significantly higher 15 days after BAC-treatment in the 13/28 group. Morphological changes in the intestinal mucosa were observed 15 days after BAC-treatment, when there was an increase in villus height (13/28 group) and crypt depth (13/28 and 21/36 groups). Cell migration rate was accelerated in the 21/36 group. No differences where found in the 13/36 group. These results show the strong effect of myenteric ablation on cell proliferation and migration in the ileal epithelium in the first 15 days of treatment in suckling and in weanling rats, and the subsequent recovery of intestinal mucosa homeostasis later on.

Are haemochromatosis mutations related to the severity of liver disease in hepatitis C virus infection?

It has been proposed that iron overload may adversely affect liver disease outcome. The recent identification of 2 mutations in the HFE gene related to hereditary haemochromatosis (Cys282Tyr and His63Asp) provided an opportunity to test whether they are associated with hepatic iron accumulation and the activity and severity of liver disease in hepatitis C virus (HCV) infection. We investigated the prevalence of HFE mutations in 135 male patients with chronic HCV hepatitis, and correlated genotype distribution with different parameters of iron status and the activity and severity of liver disease. Of these 135 patients, 6 (4.4%) carried Cys282Tyr and 32 (23.7%) carried His63Asp, frequencies which were similar to those observed in healthy controls. Serum iron levels and transferrin saturation (but not ferritin levels or liver iron content) were significantly higher in carriers than in non-carriers of HFE mutations. No difference was observed in serum ALT, AST and GGT levels between carriers and non-carriers. Finally, scores for necroinflammatory activity and fibrosis in the liver were significantly higher in HFE carriers than in non-carriers. Patients with chronic HCV infection carrying HFE mutations tend to present more evident body iron accumulation and a higher degree of necroinflammatory activity and fibrosis in the liver. HFE gene mutations might be an additional factor to be considered among those implicated in the determination of a worse prognosis of the liver disease in chronic HCV infection.

Denture-induced fibrous inflammatory hyperplasia: a retrospective study in a school of dentistry

PURPOSE

The aim of this study was to investigate the denture-induced fibrous inflammatory hyperplasia (FIH) that occurs around the borders of an ill-fitting denture, in relation to frequency of the lesion, age and sex distribution, length of denture use, and frequency of dysplasia.

MATERIALS AND METHODS

A comprehensive review of FIH diagnosed in patients wearing dentures by the oral pathology diagnostic service at the University of São Paulo over 26 years (1971 to 1996) was undertaken, based on retrospective analysis of the oral histopathologic files.

RESULTS

The frequency of FIH was 15% of the total number of pathologies diagnosed at the service of oral pathology in that period. The disorder occurred predominantly in the fifth and sixth decades of life and more often among females, at a proportion of 5:1. The frequency of FIH was higher for a length of denture use of between 1 and 10 years. Dysplasia was found in 4% of cases.

CONCLUSION

The knowledge of some aspects of FIH, especially the possible histologic alteration of dysplasia, supports the importance of the diagnosis and treatment of the lesion and suggests that any excised tissue should be submitted to histopathologic evaluation. Education and regular review of patients who have worn dentures are essential if the development of FIH is to be prevented.

Immunolocalisation of myosin-V in the enteric nervous system of the rat

We show here the localisation of myosin-V in whole mount preparations of the mucous-submucous and the muscular layers of rat small intestine by using an affinity purified antibody specific to the tail domain of myosin-V. Myosin-V immunostaining was intense in the submucous and myenteric nervous plexuses, allowing the visualisation of neuronal cell bodies and fibres. Western blots of total muscle layers homogenates detected with the same antibody revealed a single band of the expected size for myosin-V. Understanding the cellular localisation and function of this class of myosin is an important challenge and the accessibility and simplicity of the enteric nervous system as compared to the central nervous system, makes the digestive tract an attractive model for studying possible functional roles of myosin-V in neurotransmission and neuroplasticity.

Abnormal uroporphyrin levels in chronic hepatitis C virus infection

A strong association between hepatitis C virus (HCV) infection and porphyria cutanea tarda (PCT) has been observed, but the implications of the viral infection in the metabolism of porphyrins in patients without clinical manifestations of PCT are not known. The levels of porphyrin in plasma and uroporphyrin (URO) and coproporphyrin (COPRO) in 24-hour urine were measured in 156 patients with chronic HCV infection showing no clinical evidence of PCT. Levels of URO higher than the upper limit were observed in 35 of 156 patients (22.4%). The range and the mean values +/- standard deviation were 26-1,196 microg/24 hours and 82 +/- 204 microg/24 hours. Increased levels of COPRO and plasma porphyrin were observed in 12 of 156 patients (7.7%) and 2 of 156 patients (1.3%) respectively. There were no differences between patients with increased URO levels and patients with normal URO levels in terms of gender, age, risk factors for HCV infection, alcohol abuse, or hepatitis B viral infection. Transferrin saturation (p = 0.040), gamma glutamyl transpeptidase (p < 0.0001), aspartate aminotransferase (p = 0.006), and alanine aminotransferase (p = 0.040) were significantly higher in patients with abnormal URO than in patients with normal URO. The frequency of cirrhosis was higher, but not significantly different, in patients with increased URO (16.7%) compared with patients with normal URO (3.8%). The authors demonstrated that even without a clinical manifestation of PCT it is possible to detect abnormalities in the metabolism of porphyrins in patients with chronic HCV infection. The implications of these findings deserve additional investigation.

Nitric oxide is involved in the lesions of the peripheral autonomic neurons observed in the acute phase of experimental Trypanosoma cruzi infection

Our aim was to investigate the possible involvement of nitric oxide (NO) in peripheral denervation during the acute phase of murine experimental Trypanosoma cruzi infection. Wistar male rats were infected with the Y strain of T. cruzi. One group of animals was also treated with the NO synthase inhibitor N-nitro-l-arginine. A group of uninfected animals was the control. At the 18th day of infection the animals were sacrificed. Quantification of neurons in the colon and heart and tissue parasitism in the heart was performed. Serum concentration of nitrate was measured and a histochemical technique for assessing NADPH-diaphorase activity in the colon was also performed. The infected animals presented a statistically significant decrease in the number of peripheral neurons in the colon and heart and a 2-fold increase in serum NO(3) concentration compared with controls. The animals treated with N-nitro-l-arginine showed almost an absence of NO(3) concentration in the serum and did not show loss of neurons compared with controls. These treated animals displayed a 15-fold increase in tissue parasitism compared with nontreated infected animals. The NADPH-diaphorase activity was much more intense in the muscle layers of the colon of the infected animals than in those of the controls. Taken together, these data suggest that NO is involved in the peripheral denervation observed in the acute phase of experimental T. cruzi infection.

Intrinsic myenteric denervation: a new model to increase the intestinal absorptive surface in short-bowel syndrome

INTRODUCTION

Short-bowel syndrome (SBS) is caused by resection of massive portions of the small intestine and is characterized by symptoms related to malabsorption, of which severe weight loss is the most apparent. Surgical treatments for SBS are not yet satisfactory. In rats, the myenteric denervation by benzalkonium chloride (BAC) leads to development of megaileum with visceral dilatation and mucosal hyperplasia and increases the intestinal transit time. Such operation in the remaining intestinal segment after massive small bowel resection could increase the duration of contact between luminal nutrients and ileal mucosal epithelium, and furthermore, it could increase the superficial area of the mucosa. Thus, our aim in this study was to evaluate the epithelial morphology and body weight changes of animals after intrinsic ileal denervation associated with extensive small intestine resection.

MATERIAL AND METHODS

Wistar rats were submitted to resection of 80% of small intestinal length (Group R). Another group (B) of animals also received topical serosal application of BAC 0.3%. Control animals were submitted to simulated surgery (Group C). Animals were weighed weekly and sacrificed after 90 days. Intestinal walls were collected for histological procedure and morphometry.

RESULTS

At the end of the experimental period all groups showed weight increase, which was reduced in the R group (P < 0.01). Interestingly, the denervated Group B showed a marked increase in weight, similar to the control animals. Morphometric analysis of the mucosal layer area showed a major increase in mucosal surface area, mainly in Group B.

CONCLUSIONS

Our results showed that the ileal intrinsic denervation associated with massive intestinal resection induced an increase in the superficial absorptive area and was able to improve the postsurgical conditions for the animals, with accentuated weight increase. This procedure may be a useful model for further studies related to the role of the enteric nervous system on intestinal adaptations after extensive resections and may provide a new approach for the surgical treatment of short-bowel syndrome.

Proliferative activity of denture-induced fibrous inflammatory hyperplasia analyzed by proliferating cell nuclear antigen labeling index

PURPOSE

Denture-induced fibrous inflammatory hyperplasia (FIH) occurs around the borders of an ill-fitting denture. There has been no report in the literature concerning epithelial proliferative activity in FIH. The purpose of this study was to observe the labeling of proliferating cell nuclear antigen (PCNA) and evaluate its clinicopathologic results.

MATERIALS AND METHODS

The labeling index (LI) was assessed by using the PCNA, a nuclear protein synthesized mainly in the G1-S stages of the cell cycle that could be detected immunohistochemically by the monoclonal antibody PC10. The PCNA LI was assessed in FIH specimens, in clinically normal specimens 1 cm from the FIH margin (adjacent group), and in clinically normal specimens located at least 2 cm from the adjacent group; the last were considered the control group.

RESULTS

The mean PCNA LI values in the basal, parabasal, and overall epithelial layers were similar in FIH and in the adjacent group and were significantly higher than in the control group.

CONCLUSION

These data support the importance of the surgical treatment of FIH with wide excision (about 1 cm) since the clinically normal tissue around the lesion could be histologically altered.

Plasma-kallikrein clearance during liver regeneration after partial hepatectomy in the rat

AIMS/BACKGROUND

The liver clears circulating plasma-kallikrein through a receptor-mediated endocytosis process: an initial fast phase is followed by a slow exponential phase.

METHODS

To determine whether the clearance rate of plasma-kallikrein is affected during liver regeneration, we perfused isolated rat livers with rat plasma-kallikrein (rPK) at 0, 1, 2, 3 and 7 days after partial hepatectomy or sham operation.

RESULTS

Liver regeneration was followed by the expression of the proliferating-cell nuclear antigen (PCNA) labeling index. The serum concentration of alpha2-macroglobulin, an acute phase protein in rats, was measured. At day 1, the fast phase of rPK clearance rate increased in hepatectomized rats when compared with day 0 (4.9+/-0.4 and 3.7+/-0.4 mU/g liver min, p<0.05). However, at day 2, the rPK fast phase clearance rate dropped significantly (2.6+/-0.2, p<0.05), when compared with day 1. No difference was found among the sham groups at different days of hepatectomy. These changes seem to be independent of the acute phase reaction. The regenerative liver weight increased continuously during the observation period. PCNA expression increased significantly after hepatectomy, with maximal PCNA-labeling indices at days 1 and 2, declining thereafter.

CONCLUSION

The rPK fast phase clearance rate changes during liver regeneration, with a zenith occurring when PCNA labeling index is maximal (day 1) and a nadir occurring at the mitotic phase (day 2).

Effect of a necrogenic dose of diethylnitrosamine on vitamin E-deficient and vitamin E-supplemented rats

In order to evaluate the effects of a necrogenic dose of diethylnitrosamine (DEN) on vitamin E-deficient and vitamin E-supplemented rats, a single dose of the drug (200 mg/kg body weight) was injected intraperitoneally at the end of 10 weeks of treatment with the diets. The hepatic necrosis and lipoperoxidation provoked by DEN were evaluated 24, 48, 72 and 120 hours after the injection and were found to be more intense in the deficient group (thiobarbituric acid reactive substances (TBARS): 5.20 +/- 1.48 nmol/mg protein; necrosis volume: 68.99 +/- 8.36%; P < 0.05) during the second period. Also, in the same group and during the same period, mean plasma and hepatic vitamin E concentrations and mean liver glutathione concentration were the lowest detected, suggesting the occurrence of antioxidant consumption due to the toxic action of DEN. In contrast to vitamin E deficiency, which permitted the drug to exert stronger toxic effects, 20-fold supplementation with vitamin E did not provide additional protection against the lipoperoxidation and necrosis provoked by DEN (P < 0.05). The results suggest that other mechanisms in addition to lipoperoxidation provoked by free radicals originating from the metabolism of nitrosamines by the cytochrome P-450-dependent enzymatic system may be involved in the hepatotoxic action of these substances.

The relationship between myenteric neuronal denervation, smooth muscle thickening and epithelial cell proliferation in the rat colon

The effects of myenteric neuronal denervation on smooth muscle thickening and epithelial cell proliferation were studied in the descending colon of rats treated by serosal application of 2 mM benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaCl). The animals were divided into six groups of 13 animals each and killed 10, 45 and 120 days after BAC treatment. A significant reduction in neuron number was observed in the myenteric plexus of animals treated with BAC, as well as smooth muscle thickening and an increase in crypt cell population, crypt cell production per crypt and a decrease in cell cycle time. These findings permit us to conclude that a relationship may exist between the increase of epithelial cell proliferation, smooth muscle thickening and myenteric neuron denervation in the descending colon caused by BAC, the latter probably playing an important role in the integration of the other two.

Megaesophagus in rats

The objective of this study was to determine whether myenteric denervation of the abdominal esophagus using benzalkonium chloride (BAC) leads to esophageal achalasia with changes of the muscle propria and epithelial cell proliferation. The treatment led to megaesophagus 3 months after BAC application. Denervation of the esophagus induced muscle hypertrophy and increased epithelial cell proliferation. The imbalance of the neurotransmitters may play a role in these morphokinetic changes.

Disaccharidase levels in normal epithelium of the small intestine of rats with iron-deficiency anemia

Iron-deficiency anemia is the nutritional deficiency most frequently occurring throughout the world, which manifests as a complex systemic disease involving all cells, affecting enzyme activities and modifying protein synthesis. In view of these considerations, the objective of the present study was to determine the effects of iron-deficiency anemia on disaccharidases and on the epithelial morphokinetics of the jejunal mucosa. Newly weaned male Wistar rats were divided into 4 groups of 10 animals each: C6w received a standard ration containing 36 mg elemental iron per kg ration for 6 weeks; E6w received an iron-poor ration (5-8 mg/kg ration) for 6 weeks; C10w received an iron-rich ration (36 mg/kg ration) for 10 weeks; E10w received an iron-poor ration for 6 weeks and then an iron-rich ration (36 mg/kg) for an additional 4 weeks. Jejunal fragments were used to measure disaccharidase content and to study cell proliferation. The following results were obtained: 1) a significant reduction (P < 0.001) of animal weight, hemoglobin (Hb), serum iron and total iron-binding capacity (TIBC) in group E6w as compared to C6w; reversal of the alterations in Hb, serum iron and TIBC with iron repletion (E10w = C10w); animal weights continued to be significantly different in groups E10w and C10w. 2) Sucrase and maltase levels were unchanged; total and specific lactase levels were significantly lower in group E6w and this reduction was reversed by iron repletion (E10w = C10w). 3) The cell proliferation parameters did not differ between groups. On the basis of these results, we conclude that lactase production was influenced by iron deficiency and that this fact was not related to changes in cell population and proliferation in the intestinal mucosa.

The relationship between megacolon and carcinoma of the colon: an experimental approach

'Carcinoma of the colon does not occur in cases of megacolon' is an axiom held by Brazilian physicians working in endemic areas for Chagas' disease. The objective of the present study was to test this axiom experimentally by submitting rats with experimental megacolon to a carcinogen which causes carcinoma of the colon. Eighty young male Wistar rats received serosal application of either saline (0.9% NaCl) or 2 mM benzalkonium chloride (BAC) to the distal colon. Ten months later randomly chosen saline and BAC rats were injected weekly with dimethylhydrazine (DMH) for 20 weeks. Non-DMH-treated rats from both original groups were maintained, for a total of four experimental groups. Three months after the injections all surviving rats were killed. At autopsy the presence of absence of carcinomas along the colon was recorded. The induction of megacolon was evaluated by morphometry of the wall from the distal colon and myenteric denervation was assessed by neuron counts. An increase of at least 2-fold in distal colon wall thickness confirmed the induction of megacolon in BAC-treated rats. Neuronal counts from BAC and control rats not treated with DMH showed an average denervation of 63%. The number of distal colon carcinomas in BAC+DMH-treated rats was significantly lower than that in DMH-treated rats. These findings appear to contradict the traditional concept of carcinogenesis of the colon. The clinical axiom was reproduced experimentally.

Reduction of epidermal cell proliferation in skin lesions in lepromatous leprosy is greater than in indeterminate and tuberculoid leprosy lesions

We have compared epidermal cell proliferation in skin biopsies from areas with lesions to contralateral areas without lesions in patients with indeterminate, tuberculoid and lepromatous leprosy. Cell proliferation was determined as the percentage of labeled cells in the basal and suprabasal epidermal layers, using autoradiographic preparations of skin biopsies taken 1 hr after a 3H-thymidine intradermal injection. We have found a significant reduction in epidermal cell proliferation in areas with lesions in the three groups of patients. The greatest reduction occurred in lepromatous patients. In lesions of patients with indeterminate or tuberculoid leprosy, the reduction was the same, and in both groups it was smaller than in lepromatous patients. In the areas without lesions, the index of labeled cells was similar to that of "normal" skin of nonleprosy patients. In the contralateral unaffected areas from leprosy patients and in "normal" skin from nonleprosy patients, as well as in affected areas from patients with indeterminate leprosy, epidermal cell labeling was greater in the suprabasal layer than in the basal layer. In lesions of lepromatous patients, cell labeling was greater in the basal layer than in the suprabasal layer. Our findings suggest that the reduction of epidermal cell proliferation in leprosy patients is restricted to the cell-mediated immune response, more intense in lepromatous leprosy. It does not seem to be related to denervation, which is greater in tuberculoid leprosy.

Effect of chronic ethanol consumption on the activities of residual small bowel brush-border enzymes after proximal jejunum resection in the rat

Ethanol consumption has a toxic effect on the epithelium of the small bowel, but enterocyte maturity is very difficult to measure under these circumstances. However, when ethanol intake is combined with enterectomy, enterocyte immaturity is greater, permitting an easier separation of these two effects. In a group of rats (13 male Wistar rats weighing approximately 220 g) fed a liquid diet containing 35% ethanol for 4 weeks after resection of the proximal jejunum, the residual small intestine brush border maltase, sucrase, and lactase activities were similar to those of a pair-fed control group (13 animals). However, alkaline phosphatase activity was decreased in the mucosa and in the enterocyte brush border, probably because of the lower activity of this enzyme in the jejunum-ileum remnant of the alcoholic group.

[Gastrointestinal endocrine cells: brief history and main identification methods under light microscopy]

The gastrointestinal tract shows a wide spectrum of endocrine cells diffusely distributed along the mucosa, interspersed among the exocrine cells. These cells share several features such as the capacity to produce a series of peptides. Despite the development of digestive endocrinology, especially in the last decade and with respect to the biochemical knowledge and cellular localization of gastrointestinal regulatory peptides, their functional significance and their role in digestive phisiopathology remain partially unknown. This review represents a summary of the principal information about morphological and histochemical features, embryologic origin, historical data, methods of identification and types of endocrine cells, of gastrointestinal tract.

Experimental megaileum

Typical megaileum occurred in young male Wistar rats three months after ileum myenteric plexus denervation. An average of 58.4% denervation of the Auerbach plexus was obtained by serosal application of benzalkonium chloride (0.2% v/v). Denervation was assessed by ganglion cell counts in an 8 nm ring-shaped histological sectfrom the midportion of the treated segment. A morphometric study showed that the increased thickness of the megaileum wall was due to muscle hypertrophy and mucosal hyperplasia. The potential usefulness of this model of megaileum is emphasized.

Casein, hydrolyzed casein, and amino acids that simulate casein produce the same extent of mucosal adaptation to massive bowel resection in adult rats

We determined the effect of the extent of protein polymerization on the intestinal hyperplastic adaptation of adult male Wistar rats after 80% resection of the jejunal-ileal segment. Rats received one of four chemically defined solid diets prepared by using casein, two casein hydrolysates of different peptide size distributions, or free amino acids simulating casein and identical in all other components for 12 d, starting 3 d after surgery. Semipaired feeding was used to ensure that the same quantity of food was ingested by each group and as a consequence, nitrogen and energy intakes were reduced to 63% of that obtained with ad libitum feeding of the casein diet to intact rats. No significant differences were demonstrable in food ingestion, weight gain, nitrogen balance, or morphometric data for the remaining jejunal and ileal segments (number of cells/villus, number of cells/crypt, and crypt cell mitosis rate). These data demonstrate that the extent of polymerization of the protein nitrogen source did not affect the hyperplastic adaptative process of the rat. Additional studies in humans are necessary to determine whether intact protein diets can be used first as a nitrogen source in nutritional support of patients with a nonspecific hyperplastic response to surgical resection before the use of expensive hydrolysates and the more expensive amino acid mixtures.

Ileum brush border alkaline phosphatase activity in an experimental model of chronic alcoholism after small bowel proximal resection in the rat

Literature reports that chronically ingested ethanol induces changes in the morphology of the small bowel mucous membranes. It has a topical toxic effect on the epithelium of the proximal jejunum and a blood-borne effect on the epithelium of the ileum because its absorption is almost complete in the stomach, duodenum and proximal jejunum. In addition there are also reports showing stimulation of enterocyte proliferation after segmental intestine resection. In this report we compare a group of rats submitted to resection of the proximal jejunum and fed a liquid diet containing 35% of the total calories intake as ethanol for four weeks to its control pair-fed group. In both groups we studied the mucosal alkaline phosphatase (APase) activity by histochemical as well as biochemical methods. We found a decreased APase activity in the homogenate of the intestinal mucous membrane in the alcoholic group and a reduced enzymatic activity in the brush border of the ileum enterocytes, as demonstrated by histochemical qualitative and densitometric assays. The result suggests that this change in APase activity of the brush border may represent enterocyte immaturity induced by long-standing ethanol intake in the remnant ileum after proximal resection.