Mutational profile of TP53 in esophageal squamous cell carcinoma associated with chagasic megaesophagus

Chaga's disease is an important communicable neglected disease that is gaining wider attention due to its increasing incidence worldwide. Achalasia due to chagasic megaesophagus (CM), a complication of this disease, is a known-yet, poorly understood-etiological factor for esophageal squamous cell carcinoma (ESCC) development. In this study, we aimed to perform the analysis of TP53 mutations in a series of Brazilian patients with ESCC that developed in the context CM (ESCC/CM), and to compare with the TP53 mutation profile of patients with benign CM and patients with nonchagasic ESCC. Additionally, we intended to correlate the TP53 mutation results with patient's clinical pathological features. By polymerase chain reaction (PCR) followed by direct sequencing of the hotspot regions of TP53 (exon 5 to 8), we found that TP53 mutations were present in 40.6% (13/32) of the ESCC/CM group, 45% (18/40) of the nonchagasic ESCC group, and in only 3% (1/33) of the benign CM group. Missense mutations were the most common in the three groups, yet, the type and mutated exon mutation varied significantly among the groups. Clinically, the groups exhibited distinct features, with both cancer groups (ESCC and ESCC/CM) been significantly associated higher consumption of alcohol and tobacco, older age, worse Karnofsky performance status, poor outcome than the patients with benign CM. No significant association was found between TP53 mutation profile and clinical-pathological features in any of the three groups. We describe first the time the analysis of TP53 mutations in ESCC that developed in the context of CM, and the observed high frequency of mutations, suggest that TP53 also plays an important role in the tumorigenic process of this unexplored etiological condition.

Treatment of achalasia: lessons learned with Chagas' disease

Chagas' disease (CD) is highly prevalent in South America. Brazilian surgeons and gastroenterologists gained valuable experience in the treatment of CD esophagopathy (chagasic achalasia) due to the high number of cases treated. The authors reviewed the lessons learned with the treatment of achalasia by different centers experienced in the treatment of Chagas' disease. Preoperative evaluation, endoscopic treatment (forceful dilatation and botulinum toxin injection), Heller's myotomy, esophagectomy, conservative techniques other than myotomy, and reoperations are discussed in the light of personal experiences and review of International and Brazilian literature. Aspects not frequently adopted by North American and European surgeons are emphasized. The review shows that nonadvanced achalasia is frequently treated by Heller's myotomy. Endoscopic treatment is reserved to limited cases. Treatment for end-stage achalasia is not unanimous. Esophagectomy was a popular treatment in advanced disease; however, the morbidity/mortality associated to the procedure made some authors seek different alternatives, such as Heller's myotomy and cardioplasties. Minimally invasive approach to esophageal resection may change this concept, although few centers perform the procedure routinely.

Real time PCR strategy for the identification of major lineages of Trypanosoma cruzi directly in chronically infected human tissues

Two evolutionary lineages, called Trypanosoma cruzi I and II, have been identified in T. cruzi, the etiologic agent of human Chagas disease. Here, we describe a molecular strategy for direct genetic typing of these major groups of T. cruzi directly in human tissues. The protocol is based on heminested PCR amplification of the D7 region of the 24Salpha ribosomal DNA (rDNA), followed by identification of the products using denaturation curves in real time PCR. The repetitive nature of the gene, and the heminested PCR format insured the high sensitivity necessary to detect the presence of the very scarce T. cruzi DNA present in the chronically infected human tissues. There is 80% DNA sequence homology between the two 24Salpha rDNA alleles that define the T. cruzi I and II groups, sufficient to produce different thermal denaturation curves with melting temperature (TM) values of 81.7+/-0.43 and 78.2+/-0.33 degrees C (mean+/-SEM). Using this technical approach, we analysed tissue samples (esophagi, hearts and colon) from 25 different patients with the gastrointestinal or cardiac forms of Chagas disease; in all of them we found only the presence of T cruzi II. Previous epidemiological and immunological findings had already led to the idea that chronic human infections occurring in Brazil and Argentina might be primarily due to T. cruzi II strains, but all the evidence available had been indirect. Our findings provide definitive proof of this hypothesis and will also allow the establishment of which group of T. cruzi is responsible for Chagas disease in other countries.

Assessment of pulmonary function in patients before and after laparoscopic and open esophagogastric surgery

BACKGROUND

Laparoscopy is a technique used in various surgical procedures. Few studies in the literature compare stress between laparoscopic and open surgery used for esophagogastric surgical procedures. Pulmonary function is known to be significantly affected in open surgeries, increasing postoperative morbidity and mortality. The current study aimed to assess pulmonary function in patients before and after open and laparoscopic esophagogastric surgery.

METHODS

For this study, 75 patients were divided into two groups: 50 patients undergoing laparoscopy and 25 patients undergoing open surgery. The following parameters were determined by spirometry before and after surgery: forced expiratory volume in the first second (FEV(1)), forced vital capacity (FVC), and forced expiratory flow in the midexpiratory phase (FEF(25-75%)).

RESULTS

A decrease in FEV(1,) FVC, and FEF((25-75%)) was observed in the two groups on postoperative days 2, 3, and 4, as compared with the preoperative period. Likewise, FEV(1) and FVC showed a significant reduction on postoperative days 2, 3, and 4 in the patients who underwent to open surgery, but only on the day 2 in those who underwent to laparoscopic surgery. A significant decrease in FEF((25-75%)) was observed only on postoperative day 2 in the group that underwent open surgery. Significant differences in FEV(1) between the groups were observed on postoperative days 2, 3, and 4. No significant difference in FVC was noted between the groups, and a difference in FEF((25-75%)) was observed only on postoperative day 4.

CONCLUSIONS

Postoperative pulmonary dysfunction was more important for the patients undergoing open surgery than for those undergoing laparoscopic surgery.

Relationship between Trypanosoma cruzi and human chagasic megaesophagus: blood and tissue parasitism

The persistence of Trypanosoma cruzi in tissue and blood of 52 patients in the digestive form of chronic Chagas disease was studied. These patients had chagasic megaesophagus and underwent corrective surgery. Parasitologic (xenodiagnosis, hemoculture, or both), histopathologic (hematoxylin and eosin, and peroxidase-anti-peroxidase staining), and molecular (polymerase chain reaction [PCR] followed by slot-blot hybridization) tests were used in the analysis. The presence of T. cruzi, its genomic fragments, or its antigens could be detected in 98% (51 of 52) of the patients. The parasite was randomly identified in 76.9% of esophageal tissues and in 90.4% by PCR and in 73.1% by parasitologic methods from the blood. Fifty percent (26 of 52) of tissue samples had inflammation, 80.8% of which was associated with the parasite. Trypanosoma cruzi was also identified unassociated with inflammatory alterations. Higher tissue parasitism and intense inflammatory processes were observed in esophageal tissue from patients with Grade IV megaesophagus. These data demonstrate that in the digestive form of Chagas' disease, particularly in cases of megaesophagus, T. cruzi is frequently found, both in blood and tissues and may contribute to the pathogenic mechanisms involved.

Fast events in protein folding: structural volume changes accompanying the early events in the N-->I transition of apomyoglobin induced by ultrafast pH jump

Ultrafast, laser-induced pH jump with time-resolved photoacoustic detection has been used to investigate the early protonation steps leading to the formation of the compact acid intermediate (I) of apomyoglobin (ApoMb). When ApoMb is in its native state (N) at pH 7.0, rapid acidification induced by a laser pulse leads to two parallel protonation processes. One reaction can be attributed to the binding of protons to the imidazole rings of His24 and His119. Reaction with imidazole leads to an unusually large contraction of -82 +/- 3 ml/mol, an enthalpy change of 8 +/- 1 kcal/mol, and an apparent bimolecular rate constant of (0.77 +/- 0.03) x 10(10) M(-1) s(-1). Our experiments evidence a rate-limiting step for this process at high ApoMb concentrations, characterized by a value of (0. 60 +/- 0.07) x 10(6) s(-1). The second protonation reaction at pH 7. 0 can be attributed to neutralization of carboxylate groups and is accompanied by an apparent expansion of 3.4 +/- 0.2 ml/mol, occurring with an apparent bimolecular rate constant of (1.25 +/- 0.02) x 10(11) M(-1) s(-1), and a reaction enthalpy of about 2 kcal/mol. The activation energy for the processes associated with the protonation of His24 and His119 is 16.2 +/- 0.9 kcal/mol, whereas that for the neutralization of carboxylates is 9.2 +/- 0.9 kcal/mol. At pH 4.5 ApoMb is in a partially unfolded state (I) and rapid acidification experiments evidence only the process assigned to carboxylate protonation. The unusually large contraction and the high energetic barrier observed at pH 7.0 for the protonation of the His residues suggests that the formation of the compact acid intermediate involves a rate-limiting step after protonation.

Leiomyosarcoma of the esophagus in a patient with chagasic megaesophagus: case report and literature review

Leiomyosarcoma constitutes approximately 0.5% of the malignant neoplasias of the esophagus and its association with megaesophagus has not been described. We report on a case of a woman with dysphagia that was slowly progressive from the age of 19 due to chagasic megaesophagus. The woman was subjected to cardiomyotomy at the age of 49. She presented a rapid worsening of the dysphagia due to leiomyosarcoma at the age of 61, and was subjected to subtotal esophagectomy with cervical esophagogastroplasty. She developed pulmonary and hepatic metastases 14 months after surgery and died six months later.

Decreased CD4(+) circulating T lymphocytes in patients with gastrointestinal chagas disease

The gastrointestinal form of Chagas disease is characterized by lumenal enlargement and wall thickening of the esophagus and/or colon. Very little is known about the involvement of the immune system in the development of the gastrointestinal form of the disease. In this paper we describe our initial observations on the phenotypic analysis of peripheral blood mononuclear cells from patients with the gastrointestinal form of Chagas disease. A significant decrease in the absolute number of CD3(+) T cells as well as in CD19(+) B lymphocytes was observed. However, the most striking observation was an inversion of the CD4/CD8 ratio, contrasting with results from cardiac chagasic patients in whom the ratio is normal. A decrease of the percentage of CD4(+)CD28(+) cells and an increase in the expression of HLA-DR both on CD4(+) and on CD8(+) cells suggest that although these T cells express activation markers their function may be altered by the lack of CD28 expression.

Evidence for survival and metabolic activity of encapsulated xenogeneic hepatocytes transplanted without immunosuppression in Gunn rats

BACKGROUND

Hepatocyte transplantation could be an alternative to whole organ transplantation to correct enzymatic disorders. To this end, it would be of major importance to use xenogeneic cells without immunosuppression. The aim of this study was to investigate the survival and metabolic activity of encapsulated xenogeneic hepatocytes in the absence of immunosuppression. For this purpose, we used Gunn rats genetically incapable of bilirubin conjugation.

METHODS

Xenogeneic (from guinea pigs) and allogeneic (from Lewis rats) hepatocytes (2x10(7)) were isolated, macroencapsulated in hydrogel hollow fibers made with an acrylonitrile-sodium methallyl-sulfonate copolymer, and transplanted into the peritoneum of Gunn rats without any immunosuppression. Plasma bilirubin levels were evaluated weekly. Bilirubin conjugates in bile and cell morphology were studied after 5 and 12 weeks, respectively.

RESULTS

In Gunn rats transplanted with xenogeneic hepatocytes, a significant decrease in the serum bilirubin level was observed between 3 and 9 weeks after transplantation when compared with controls transplanted with empty hollow fibers: it fell to 62% of the initial level at weeks 5-7 (P < 0.01). A comparable result was observed in Gunn rats transplanted with encapsulated allogeneic cells. Bilirubin conjugates were observed in bile samples of rats transplanted with encapsulated hepatocytes. After explantation, hollow fibers appeared intact with minimal fibrosis. Cell viability and hepatocyte morphology were preserved.

CONCLUSIONS

These results indicate that macroencapsulated xenogeneic hepatocytes can survive and remain functional for more than 2 months when transplanted in vivo in the absence of any immunosuppression.

Transplantation of allogeneic hepatocytes without immunosuppression: long-term survival

BACKGROUND

Hepatocyte transplantation could be an alternative to whole liver transplantation. Allogeneic hepatocytes are rejected if transplanted without immunosuppression. The aim of this study was to transplant allogeneic hepatocytes in the peritoneum and to protect them from rejection by encapsulation in a new semipermeable membrane.

METHODS

Rat hepatocytes were encapsulated in hydrogel-based hollow fibers, obtained from AN69 copolymer, before being transplanted into the peritoneum of rats. Outcome of allogeneic hepatocytes encapsulated in hollow fibers was compared with that of syngeneic hepatocytes encapsulated in hollow fibers, with that of free allogeneic hepatocytes, and with allogeneic hepatocytes encapsulated in hollow fibers left open. Cell viability was assessed by erythrosin exclusion, structure by electron microscopy, and function by albumin release.

RESULTS

Up to 90 days, viability of allogeneic hepatocytes in hollow fibers was greater than 80%. The structure remained normal at electron microscopy. Albumin release was 16.5 +/- 0.3 micrograms/24 hr/10(6) hepatocytes (day 15), 14.2 +/- 2.0 micrograms/24 hr/10(6) hepatocytes (day 30), 8.8 +/- 0.1 micrograms/24 hr/10(6) hepatocytes (day 60), and 11.4 +/- 0.3 micrograms/24 hr/10(6) hepatocytes (day 90). Free hepatocytes and hepatocytes in hollow fibers left open did not survive at day 15.

CONCLUSIONS

Viability and function of encapsulated allogeneic hepatocytes were maintained up to 90 days after transplantation, without immunosuppression.