Water as Veneering Modeling Liquid Affects Microhardness of Glassy Matrix Veneering Ceramic.

PURPOSE/AIM: To evaluate the effect of different veneering liquids used for modeling on microhardness, fracture toughness and biaxial flexural strength of a glass-veneering ceramic. MATERIAL AND METHODS: The manufacturer recommended modeling liquid (ML), distilled water (DW), isopropyl alcohol (IA), 0.5% (P05), 1% (P1), and 2% (P2) polyethylene glycol solutions were mixed with feldspathic ceramic powder to form disc-shaped samples (n=20, 15 mm × 1.2 mm). After sintering, samples were mirror-polished and subjected to Vickers indentation (n=5) for measurement of microhardness and fracture toughness. The remaining 15 samples from each group were subjected to biaxial flexural strength. Data were subjected to one-way ANOVA and Weibull analysis. RESULTS: The microhardness was affected by veneering liquid (p=0.002): DW promoted higher microhardness values than ML and IA. Fracture toughness (p=0.301) and flexural strength (p=0.930) were not affected by the veneering liquid but Weibull parameters were affected. All groups presented surface pores under high magnification. CONCLUSION: Even though the use of DW led to higher values of surface microhardness than the ML, all obtained values are inside the range of enamel microhardness values reported in the literature. Such parameters may affect antagonist wear and should be reported in clinical trials.

Bordetella pertussis infection in paediatric healthcare workers.

An increased incidence of pertussis has been observed recently in adults, and healthcare workers (HCWs) are considered a risk group for transmission to infants. Prevalence of recent pertussis infection was assessed in HCWs from a paediatric department of a tertiary care hospital in Brazil. Serum pertussis toxin IgG antibodies were measured by enzyme-linked immunosorbent assay. Of 388 HCWs included in the analysis, 6.4% had serology suggestive of recent infection. Medical residents [odds ratio (OR): 4.15; 95% confidence interval (CI): 1.42-12.14; P = 0.009] and those working >40 h a week (OR: 3.29; 95% CI: 1.17-9.26; P = 0.024) had increased risk of pertussis infection.

Analysis of the mechanism of action of the Brazilian type (Agamma-195 C --> G) of hereditary persistence of fetal hemoglobin.

We report an in vitro expression study of the Agamma-globin gene promoter containing the Agamma-195 C --> G mutation that causes the Brazilian type of hereditary persistence of fetal hemoglobin (HPFH). To demonstrate that this mutation results in increased promoter strength, we evaluated the mutant promoter linked to the hypersensitive site-2 of the locus control region with the luciferase reporter gene system and examined protein interactions by eletrophoretic mobility shift assay. The transient expression was studied in three cell lines: K562, HEL and 293, and indicated increased promoter activity of the promoter containing the Brazilian mutation in all cell lines. The protein-DNA interaction showed that, in contrast to the Agamma-198 T --> C mutation which has increased affinity for the Sp1 protein and creates a motif that behaves like a novel CACCC box in the gamma promoter, the Brazilian HPFH mutation decreases the affinity at the Sp1 protein and does not act as a CACCC motif. These results suggest that this mutation may act to increase the Agamma-globin chain production. In addition, the mechanism by which this increased production occurs is different to that of the -198 mutation. Other proteins may be involved in the overexpression of the gamma-globin chain and/or may be dependent upon the DNA structure.

Characteristics of nasal T/NK-cell lymphoma among Brazilians.

Nasal T/NK-cell lymphomas are highly associated with Epstein-Barr virus (EBV). They are more frequent in Asia than in Western countries. In Central and South America there are few studies about nasal T/NK-cell lymphoma and they have shown a strong predominance of this phenotype in Native American descents, supporting the hypothesis of a racial predisposition for the disease. We studied the lymphomas involving midline facial region at a Brazilian institution. T/NK cell lymphomas (16/25) were more frequently found compared to B lymphomas (9 cases, all B large cell). T/NK cell lymphomas involved predominantly the nasal region. Histologically they showed angioinvasion and necrosis. All of them were positive for CD3 and CD56 and showed numerous tumor cells labeled by EBER-1. Although disease was localized in 61% at diagnosis, there was no tendency to cure. The racial distribution of patients with T/NK-cell phenotype was similar to that found in B-cell lymphomas. EBV was more frequently found in adenoids than in palatine tonsils. In inflammatory lesions of the nasal and palatal regions EBV was not found. In the present study the relative frequency of T/NK versus B cell sinonasal lymphomas was high and similar to that observed in other Latin American countries. However, there was not any racial association with T/NK-cell phenotype and the tumor showed an agressive behavior similar to that reported in Asia. The high frequency of EBV-positive lymphocytes in nasopharyngeal lymphoid tissue (adenoids) suggests that they could serve as a reservoir for the virus.

Thyroid dysgenesis caused by PAX8 mutation: the hypermutability with CpG dinucleotides at codon 31.

We identified a novel mutation (CGC to T GC) at codon 31 of the Paired box 8 gene, an important transcription factor in the development of the thyroid gland. Mutations at this codon have been independently reported in 2 cases (CGC to CA C). These transitions are considered typical CpG-consequence mutations and account for hypermutability at this position.

[Surgical treatment of colorectal cancer. 10-year experience at the INCMNSZ]. / Tratamiento quirúrgico del cáncer colorrectal. Experiencia de 10 años en el INCMNSZ.

OBJECTIVE: To analyze the short- and long-term outcomes of the surgical treatment for colorectal cancer at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ) in Mexico City. BACKGROUND: Colorectal cancer is the second most frequent malignant tumor of the digestive tract in Mexico. Its incidence is rising, and its identification in early stages is important to offer a curative surgical treatment. METHODS: Retrospective, descriptive observational trial. We studied 165 patients who underwent colorectal surgery for treatment of cancer between 1985 and 1994 at the INCMNSZ. We compared the variables of patients and the surgical procedures and their relationship with morbidity and mortality with 5-year survival. RESULTS: Survival was greater in curative-attempting procedures of the colon than of the rectum (p < 0.05). Survival rate was also greater in earlier stages of the disease at the moment of diagnosis. Surgical morbidity occurred in 30% due to wound infections in most cases. Mortality rate was 3.6%, while the main cause was sepsis. Patients > 65 years of age had a higher mortality rate. Rectal surgery had higher morbidity than colonic surgery. CONCLUSIONS: Detecting patients at earlier stages of the disease is required to offer them a curative-attempting surgery procedure. Stage at moment of diagnosis correlates with survival rates. Age was a risk factor for surgical mortality, and rectal surgery, a risk factor for morbidity.

Conventional chemotherapy for acute myeloid leukemia: a Brazilian experience.

CONTEXT: Young patients affected by acute myeloid leukemia (AML) achieve complete remission (CR) using conventional chemotherapy in about 55-85%. However, 30% of patients fail to achieve CR and the remission duration is often only about 12 months. More intensive treatment after CR seems to be necessary in order to maintain CR and obtain a definitive cure. In Brazil, few reports have been published on this important subject. OBJECTIVE: The aim of this study was to describe a Brazilian experience in the treatment of "de novo" acute myeloid leukemia (AML) in younger adult patients (age < 60 years). DESIGN: Retrospective analysis. SETTING: University Hospital, Hematology and Hemotherapy Center, State University of Campinas, Brazil. PARTICIPANTS: Newly diagnosed cases of "de novo" AML in the period from January 1994 to December 1998 were evaluated retrospectively, in relation to response to treatment, overall survival (OS) and disease free survival (DFS). Cases with acute promyelocytic leukemia (APL) were also included in this analysis. RESULTS: On the basis of an intention to treat, 78 cases of AML, including 17 cases of APL, were evaluated. The overall median follow-up was 272 days. The complete remission (CR) rate was 63.6% in the AML group (excluding APL) and 78% in the APL group. The 5-year estimated disease-free survival (DFS) was 80% for the APL group and 34% for the AML group (P = 0.02). The 5-year estimated overall survival (OS) was 52% for the APL group and 20.5% for the AML group, respectively (P = NS). Relapse was observed in 12/39 (30.7%) patients with AML and 1/11 (9%) with APL. CONCLUSIONS: These results are similar to those reported in the literature. However, relapse and mortality rates remain high, and a search for more aggressive strategies in order to prevent relapse is recommended.

Toxic pseudomembranous colitis in a patient with ulcerative colitis.

UNLABELLED: Toxic colitis is a severe disease that may be caused by several inflammatory and/or infectious diseases. Ulcerative colitis is one of the most frequent causes of toxic colitis in the United States. Toxic megacolon complicating Clostridium difficile colitis is a rare occurrence with significant morbidity and mortality. CASE REPORT: A 52-year-old male presented with rectal bleeding and tenesmus. He had been treated for amebiasis with metronidazole, and had improved. Two weeks later, symptoms recurred, and he was referred to our hospital. A sigmoidoscopy and biopsies demonstrated mucosal ulcerative colitis. He underwent treatment with systemic prednisone, mesalamine, and hydrocortisone enemas with adequate response. He was asymptomatic for 2 months, but later presented with a tender abdomen and rectal bleeding. Plain abdominal and thorax films showed colonic distention and free intraperitoneal air. Emergency laparotomy was performed, and an inflamed and distended colon, with free inflammatory liquid in the peritoneum, was found. A total abdominal colectomy with temporary ileostomy and Hartmann's pouch was performed. The histopathology analysis demonstrated a Clostridium difficile pseudomembranous colitis. CONCLUSION: The presence of toxic megacolon due to Clostridium difficile in patients with ulcerative colitis is a rare complication that may be suspected in patients with initial relapse who are on antibiotics.

[Quality of the presentation of free research papers in the National Congress of Gastroenterology: Morelia-1997]. / Calidad de presentación de los trabajos libres de investigación en el Congreso Nacional de Gastroenterología: Morelia-1997.

BACKGROUND: The quality of the presentation of a free paper in a medical congress is not necessarily related to the quality of the methodology. OBJECTIVE: To analyze the quality of the presentation of the free papers in the National Congress of Gastroenterology in Mexico (Morelia-1997). METHODS: A prospective study was designed to evaluate the following aspects: Limitation to time assigned, adequate use and design of slides, and mentioning of the main methodologic characteristics. RESULTS: There was a high quality of presentation in the majority of papers. The most frequent problems identified, amenable to improvement, were non-limitation to assigned time (24%), as well as problems in the design of slides (too many lines/columns in 32% and excessive number in 23%). CONCLUSIONS: The knowledge of the results may help to improve the presentations of the free papers in the national congresses of gastroenterology.

[Total proctocolectomy with ileo-anal reservoir in "J". Experience at the Salvador Zubirán National Institute of Nutrition]. / Proctocolectomía total con anastomosis ileo-anal de reservorio en "J". Experiencia en el Instituto Nacional de la Nutrición Salvador Zubirán.

BACKGROUND: Total proctocolectomy with ileal pouch-anal anastomosis (TPCIAA) is the procedure of choice for patients with Ulcerative Colitis and Familial Adenomatous Polyposis. The frequency of presentation of both diseases is low in Mexico, therefore the experience with the surgical procedure is limited. OBJECTIVE: To analyze the operative morbidity and mortality and long-term functional results in a series of patients operated upon with the TPCIAA in a referral center in Mexico. MATERIAL AND METHODS: Retrospective analysis of 44 consecutive patients operated upon from 1987 through 1997. The operation included resection of the anal transitional zone, handsewn anastomosis of a "J" pouch, and diverting ileostomy in all cases. Operative morbidity and mortality, and long-term functional results and complications were determined. RESULTS: Mean age was 33 +/- 15 years. There were 52% women and 48% men. Diagnoses were ulcerative colitis in 59% and familial polyposis in 36%. Global morbidity was 39%, and mortality 2%. With a mean follow-up of 24 months, mean number of bowel movements was 4, 10% of patients had diurnal spotting, 30% nocturnal spotting, and no patient had gross incontinence. Three patients presented pouchitis with adequate response to antibiotics. Two patients presented long-term pouch fistulas that did not require pouch excision. CONCLUSIONS: The TPCIAA is a feasible operation with acceptable rates of morbidity and mortality and satisfactory functional results.

A surface plasmon resonance assay for the binding of Amaranthus hypochondriacus var. Mexico lectin to glycoprotein.

We have used the analytical system based on surface plasmon resonance to monitor the interaction between Amaranthus hypochondriacus var. Mexico lectin and four different fetuins; fetuin, asialofetuin, agalactofetuin, and agalactosaminofetuin. Agalactofetuin and agalactosaminofetuin were prepared by enzymic digestion of asialofetuin using jack bean beta-galactosidase or endo-alpha-N-acetylgalactosaminidase from Diplococcus pneumoniae. Ligands were immobilized onto a sensor surface via amide linkages. The lectin interacted most strongly with asialofetuin, but not with agalactosaminofetuin. The binding of the lectin to asialofetuin was inhibited by N-acetylgalactosamine or Gal beta 1-->3GalNAc in a dose-dependent manner.

[Retrorectal tumors]. / Tumores retrorrectales.

OBJECTIVES: To analyze the clinical presentation, and diagnostic and therapeutic implications in patients with retro-rectal tumors. METHODS: This paper reports two patients. Both patients had constipation and change in bowel habits, and the physical examination revealed the retro-rectal neoplasia. One of the patients had rectal intra-luminal invasion due to a schwannoma and underwent a transanal excision, with subsequent recurrence that required a combined abdomino perineal resection due to invasion of the tumor to the anorectal angle. The second patient had a teratoma and had a good outcome after a trans-sacral resection of the neoplasia. CONCLUSIONS: Clinical suspicion is imperative to diagnose these rare tumors. Treatment of choice is complete resection of the tumor. Localization of the neoplasia, as evidenced by image studies will help to decide the best surgical approach.

Fulminant amebic colitis: analysis of 55 cases.

UNLABELLED: Fulminant amebic colitis is a rare disease with high morbidity and mortality. PURPOSE: This study was designed to identify the most frequent clinical and histopathologic features of fulminant amebic colitis and to analyze results of surgical treatment and the existence of risk factors for mortality. MATERIALS AND METHODS: A retrospective analysis was conducted of clinical and histopathologic data of 55 patients with fulminant amebic colitis. Data were obtained from the files of autopsies and surgical operations that had been performed at a referral center in Mexico from 1943 through 1994. RESULTS: Median age was 52 (range, 18-79) years. There were 34 men (62 percent) and 21 women (38 percent). Diabetes mellitus and chronic alcoholism were the most frequent diseases in association with fulminant amebic colitis (40 and 31 percent, respectively). The most frequent clinical manifestations were abdominal pain, diarrhea, rectal bleeding, and fever. There was a coexistent amebic liver abscess in 54 percent of patients. The main histopathologic characteristics were necrosis, presence of trophozoites, and acute and/or chronic inflammation. Of 25 patients who underwent surgery, only six survived (operative mortality, 76 percent; overall mortality, 89 percent). The variables that correlated with mortality were longer duration of symptoms, lower count of leukocytes, nonsurgical treatment, nonresective surgical procedure, hospital admission before 1971, and invasion of trophozoites into or through the muscularis. CONCLUSIONS: The results may help to obtain an earlier diagnosis and establish proper treatment of fulminant amebic colitis.

Active hypothalamic-pituitary-gonadal axis in an infant with X-linked adrenal hypoplasia congenita.

To evaluate the hypothalamic-pituitary-gonadal axis in an infant with adrenal hypoplasia congenita, we measured the serum levels of testosterone and performed a luteinizing hormone-releasing hormone stimulation test. The diagnosis was made because of the presence of a mutation, A300V, in the DAX-1 gene. The results demonstrated an active hypothalamic-pituitary-gonadal axis, with adult-level testosterone of 266 ng/dl on day 0, and maintenance of testosterone concentration in the 100 to 250 ng/dl range for 140 days as expected. The luteinizing hormone-releasing hormone lest was compatible with an active pituitary gland with a luteinizing hormone peak of 13.1 IU/L and a follicle-stimulating hormone of 5.0 IU/L We conclude that the DAX-1 mutation does allow a normal reproductive axis at birth. We speculate that sometime between infancy and puberty this mutation in the DAX-1 gene leads to an inability to activate the reproductive axis from its childhood suppression; thus puberty will not develop in this infant.

[Surgical treatment of colonic volvulus. 10-year experience at the Instituto Nacional de la Nutrición Salvador Zubirán]. / Tratamiento quirúrgico del vólvulus colónico. Experiencia de 10 años en el Instituto Nacional de la Nutrición Salvador Zubirán.

OBJECTIVES: To analyze morbidity-mortality and results of surgical treatment for colonic volvulus. METHODS: Retrospective review of 33 patients who underwent surgical treatment for colonic volvulus from 1986 through 1996. RESULTS: Mean age was 62 +/- 20 years (SD) with predominance of female sex (2:1). There were 25 cases of sigmoid volvulus (76%), 7 in the cecum (21%) and 1 in the transverse colon (3%). Colonic necrosis and/or perforation were most frequently seen in the right and transverse colon (50%) than in the sigmoid (4%) (P < 0.002). Operative morbidity was 45% with mortality of 21%. Age was the only variable statistically significant for operative morbidity (52 +/- 23 years in patients without morbidity vs 71 +/- 17 years in patients with morbidity, P = 0.02). Surgical procedures for sigmoid volvulus were resection in 13 and fixation in 12. Recurrence after fixation was 38% to 12 months and 69% to 24 months (Kaplan-Meier), with associated mortality of 50%. There was no recurrence after resections. Treatment for cecal volvulus was cecopexy in 4 cases, with one recurrence; and right hemicolectomy without recurrence. CONCLUSIONS: The results should encourage resective procedures in sigmoid volvulus because the risk of recurrence after fixation is high and the morbidity-mortality is similar. Elderly patients are more susceptible to complications.

Purification and characterization of a lectin from Amaranthus hypochondriacus var. Mexico seeds.

A lectin from Amaranthus hypochondriacus var. Mexico (AHML) was purified by affinity chromatography using asialofetuin-Sepharose 4B. AHML is specific for N-acetyl-D-galactosamine as are the other Amaranthus lectins. AHML has no carbohydrate moiety and requires no metal ion for the hemagglutination activity. The pI of AHML is 6.8. AHML has a native molecular mass of 45.0 kDa and is composed of homo-subunits having molecular masses of 36.8 kDa.

Case report of primary squamous carcinoma of the rectum.

PURPOSE: To report a patient with primary squamous carcinoma of the rectum. CASE REPORT: A 40-year-old woman with hematochezia and change in bowel habits was studied. The main laboratory finding was a mild anemia. A barium enema and a proctoscopy revealed a rectal neoplasm at eight cm from the anal verge. A transendoscopic biopsy demonstrated an squamous rectal carcinoma. A transrectal ultrasound and CT scan of the abdomen revealed a big rectal mass with transmural affection and possible involvement of the lymph nodes. The carcinoembriogenic antigen (CEA) was high (32 ng/mL). The patient underwent radiotherapy with 46 Gy, and 5-fluorouracil as radiosensitizer. Three months later, a new CT scan showed significant reduction of the size of the mass, and the patient underwent a very low anterior resection with double-stapled anastomosis. The analysis of the specimen showed a squamous carcinoma of the mid-rectum, invading through the wall without lymph node affection and with proximal, distal, and radial margins free of tumor. The CEA returned to normal after surgery (1.3 ng/mL). The patients is alive and without evidence of disease 18 months after the operation. CONCLUSION: Primary squamous carcinoma of the rectum is a rare disease, and surgery seems to be a good option of treatment, with the possibility of sphincter preservation depending upon the location of the tumor.

[Mucocele of the vermiform appendix]. / Mucocele del apéndice vermiforme.

BACKGROUND: Mucocele is a cystic dilatation of the vermiform appendix that contains mucous material. It may be caused by benign or malignant diseases. AIM: To report and discuss four cases with mucocele. REPORT OF CASES: The main clinical manifestations were abdominal pain and changes in the bowel habits. In two cases, appendiceal mucocele was an incidental finding in the diagnostic work-up or operation for acute diverticulitis and acute cholecystitis, respectively. The diagnostic approach included barium enema and CT scan of the abdomen. In three cases, the mucocele was secondary to mucinous cystadenoma; two of them had a preoperative diagnosis of mucocele and underwent colonic preparation and right hemicolectomy, one patient underwent appendectomy alone. The remaining case underwent appendectomy alone, was found to have mucinous adenocarcinoma, and underwent a right hemicolectomy in a second operation. Postoperative outcome was adequate in all cases. CONCLUSION: Mucocele of the vermiform appendix is a rare disease. An appendectomy is an adequate treatment for benign disease. If malignant disease is demonstrated, a right hemicolectomy should be performed.

[Surgical alternatives in the treatment of chronic unspecific ulcerative colitis]. / Alternativas quirúrgicas para el tratamiento de la colitis ulcerativa crónica inespecífica.

BACKGROUND: Newer techniques for surgical treatment of chronic ulcerative colitis have been developed. PURPOSE: This review article analyzes the current surgical alternatives, attempting to define their role in the overall management of patients with chronic ulcerative colitis. RESULTS: Non-restorative total proctocolectomy with permanent ileostomy remains as the gold-standard operation for chronic ulcerative colitis. Restorative total proctocolectomy, with or without excision of the anal transitional zone, is becoming one of the most widely used procedures for this disease. It avoids a permanent ileostomy, and permits good functional results in the majority of patients. Subtotal proctocolectomy, with a Hartmann Pouch may be an adequate procedure in patients operated upon on emergency basis, to permit an ileo-anal pouch in a subsequent operation. Colectomy with ileo-rectal anastomosis, and creation of a continent ileostomy are procedures that should be limited to selected candidates. CONCLUSIONS: Currently, total proctocolectomy with ileo-anal pouch seems to be the operation of choice in the majority of patients, but the preoperative general status is important to define the best surgical alternative for each patient.