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Biomedical subjects

A Angeles-Angeles

Publications and source records attributed to A Angeles-Angeles.

At least 19 recordsLinked to original sources
PubMed2002

Laparoscopic approach to fever of unknown origin.

BACKGROUND: Fever of unknown origin (FUO) is difficult to diagnose. Laparotomy is needed to establish the etiologic diagnosis in some patients. The aim of this study was to analyze the feasibility, safety, and success rate of a protocolized laparoscopy in patients with FUO. METHODS: An extensive clinical evaluation was performed before surgery. Laparoscopy included inspection of the abdominal cavity, wedge and tru-cut liver biopsies, lymph node biopsy, splenectomy, and bone marrow biopsy. Histologic analysis, permanent section analysis, and cultures were obtained. RESULTS: The study involved 15 patients with a mean age of 43.6 +/- 14.5 years. The mean operative time was 122 +/- 60 min. Minor complications occurred in 9% of the patients. One patient bled after surgery and underwent reoperation. There was no operative mortality. An etiologic diagnosis was made in 66% of the patients, and laparoscopy helped to rule out intraabdominal pathology in four additional patients, giving a total success rate of 93%. CONCLUSION: Protocolized laparoscopy in patients with FUO is safe, feasible, and accurate.

Feasibility Studies↗
PubMed2001

Histologic diagnosis of primary hyperparathyroidism: a concordance analysis between three pathologists.

Primary hyperparathyroidism (HPT) is caused by a parathyroid adenoma, hyperplasia or carcinoma. Difficulties for the histologic diagnosis of abnormal parathyroid tissue are widely recognized. The aim of the study was to evaluate the reproducibility of the morphologic criteria through a concordance study among three pathologists. Representative slides of 40 patients with biochemically primary HPT stained with hematoxylin and eosin were blindly reviewed by three pathologists. Each pathologist established the diagnosis of adenoma or hyperplasia and assessed the presence of fat cells, a rim of normal tissue, a fibrous capsule, the number of cellular types, the lobular pattern, and the characteristics of the blood vessel's wall. A concordance analysis was then performed. Mean age of the group was 55 +/- 14 yr, 7 were males and 33 females. The concordance analysis among the three pathologists for the differential diagnosis between adenoma and hyperplasia, showed a Kappa index of 0.5. Kappa index for the presence of fat cells was 0.56, for the presence of a rim of normal tissue 0.47, and for the number of cellular types 0.29. The concordance for the differential diagnosis between parathyroid adenoma and hyperplasia in this study was low.

Adenoma↗
PubMed2000

Carcinoid tumors of the extrahepatic bile ducts: a study of seven cases.

The authors report seven patients with carcinoid tumors of the extrahepatic bile ducts (EHBDs). All patients were women, with an average age at diagnosis of 49.8 years (range, 37-67 yrs). The most common presenting symptom was painless jaundice with or without pruritus. Although one patient had peptic ulcer disease before the onset of obstructive jaundice, none had systemic endocrine manifestations. These neoplasms were most often located in the common bile duct. Grossly, the carcinoid tumors were usually nodular and poorly demarcated, and ranged from 1.1 to 2.7 cm in size. Only one of the neoplasms was polypoid. Microscopically, the tumors had a trabecular or nesting pattern with occasional tubule formation, and were composed of relatively small cells with granular chromatin. All of the neoplasms expressed chromogranin and two expressed synaptophysin. Three expressed serotonin and two of the three were also immunoreactive for pancreatic polypeptide or somatostatin. Two tumors were focally positive for gastrin and one of these two tumors was also positive for serotonin and pancreatic polypeptide. All seven carcinoid tumors showed no immunoreactivity for p53, and assays for p53 loss of heterozygosity analysis were negative in two, suggesting that p53 mutations do not play a role in the pathogenesis of EHBD carcinoids. A mutation in codon 12 of K-ras was found in one carcinoid tumor whereas two of two showed immunoreactivity for Dpc4 protein. In view of the small number of carcinoids studied, the importance of these findings in the pathogenesis of these tumors is unclear. Ultrastructural examination of three of the tumors revealed numerous membrane-bound, round neurosecretory granules. Clinically, these lesions had an indolent course. Even in the presence of lymph node metastases (noted in two patients), all of the patients remained disease free 2 to 11 years (average follow up, 6.6 yrs) after segmental resection or pancreaticoduodenectomy (Whipple's procedure). Because carcinoid tumors of the EHBD are of low malignant potential, they should be separated from the more common adenocarcinomas in this location.

Adult↗
PubMed1999

High prevalence of a 30-base pair deletion in the Epstein-Barr virus (EBV) latent membrane protein 1 gene and of strain type B EBV in Mexican classical Hodgkin's disease and reactive lymphoid tissue.

Depending on geographic location and patient age Hodgkin's disease (HD) is associated with Epstein-Barr virus (EBV), mostly type A EBV, in 20% to 100%. The highest prevalence occurs in children of developing countries. Molecular analysis of the oncogene coding for the latent membrane protein 1 (LMP-1) revealed a 30-base pair (bp) deletion in up to 46% of EBV-positive HD. We investigated the presence of EBV in a series of Mexican classical HD (n = 57) and reactive lymphoid tissues (n = 20) from a private and a public hospital with special emphasis on the prevalence of the 30-bp deletion and the type of EBV. EBV infection was analyzed at the cellular level by Epstein-Barr encoded early RNA transcripts (EBER) in situ hybridization (ISH) and by LMP-1 protein immunohistochemistry (IHC). Molecular analysis of the LMP-1 gene configuration was performed by polymerase chain reaction (PCR) with primers spanning the site of the deletion and subsequent Southern and/or dot blot hybridization using wild-type and deletion-specific probes. The prevalence of type A and type B EBV was investigated by PCR-analysis for divergence in the coding region of Epstein-Barr nuclear antigen (EBNA)-2. EBV was detected in Hodgkin- and Reed-Sternberg cells (H-RS) by LMP-1 IHC and/or EBER ISH in 35/57 (61%) Mexican HD including 18/32 (56%) with nodular sclerosis, 15/20 (75%) with mixed cellularity and 2/4 (50%) with lymphocyte depletion. In addition, LMP-1 gene sequences were detected by PCR in 9 cases of HD without LMP/EBER expression by H-RS cells and in 17/20 (85%) reactive lymph nodes, supposedly originating from rare latently infected B cells. Surprisingly, the 30-bp LMP-1 deletion was found in 28/35 (80%) EBV-positive HD. This deletion, however, was also found in all 9 (100%) HD with H-RS cells negative for EBV and in 10/17 (59%) reactive lymph nodes. Thus, the overall LMP-1 del prevalence in reactive tissue is 73% (19/26). Typing of EBV was successful in 26 cases of EBV-positive HD, 10 of these were infected by type B EBV (38%). Of the reactive lymphoid tissue, 9 (47%) were infected by type A, and 10 (53%) by type B; All 20 cases (100%) associated with type B, whether neoplastic or reactive, displayed the LMP-1 del variant compared with 18/25 (72%) infected by type A EBV. To our knowledge, this is the highest incidence for both the LMP-1 deletion variant and the infection by type B EBV in HD reported so far worldwide. Our data suggest that EBV infection contributes to the pathogenesis of the majority of Hodgkin's disease cases in Mexico. The specific tumorigenic role of the LMP-1 deletion variant, however, is doubtful with regard to its high frequency in nonneoplastic lesions. Moreover, type B infection frequently occurs in Mexican HD and reactive lymphoid tissue and is consistently associated with the deletion variant pointing to a pathogenetic role of this combined genotype.

Adolescent↗
PubMed1999

Obstructive jaundice as the first clinical manifestation of a metastatic malignant melanoma in the ampulla of vater.

The authors report a patient with obstructive jaundice as the first clinical manifestation of a primary malignant melanoma metastatic in the ampulla of Vater. After the histologic diagnosis of the metastases was made, the primary tumor was located in the skin of the back. Obstruction jaundice secondary to ampullary obstruction due to metastatic melanoma has only been reported twice, and in neither case was jaundice the first symptom of the disease.

Ampulla of Vater↗
PubMed1999

Oral manifestations as a hallmark of malignant acanthosis nigricans.

We present a case of malignant acanthosis nigricans (AN) that initially manifested in the oral cavity. In the present report, the patient had typical clinical and histological findings of oral and esophageal AN, with subtle skin changes, associated with a gallbladder adenocarcinoma. The importance of the clinical oral examination is emphasized because the recognition of oral lesions led to the diagnosis of AN and to the following detection of the internal malignancy. Since the tumours associated with AN are highly malignant, it is of the utmost importance to recognize the skin and mucous membrane changes in adults.

Acanthosis Nigricans↗
PubMed1998

A clinicopathologic variant of intramucosal early gastric cancer with widespread dissemination: report of three cases.

We describe the clinicopathological characteristics and postmortem findings of three cases of intramucosal early gastric cancer (EGC) selected from nine cases of our series to characterize its unusual clinical behavior. All patients were treated at the Instituto Nacional de la Nutricion in Mexico City between January 1986 and December 1995. The following features were the most salient of the three cases: (1) The tumors were constituted by only few nests of intramucosal cells; two of them were signet-ring cell carcinomas and the other one was of the intestinal type. (2) Grossly, all tumors were inconspicuous. (3) All the patients had a short clinical course and in none of them the clinical diagnosis was suspected. (4) A wide dissemination was found at autopsy; additionally, in two of the cases, extensive lymphatic and venous thrombi and multiple secondary hemorrhages were found. (5) In all patients, the symptoms and deaths were caused by the metastases. No cases as early as those reported here were found either in the Japanese or in Western literature. Although larger series of EGC should be studied in our country, these findings suggest that at least in Mexico there is a group of EGC with unusual aggressive behavior.

Adenocarcinoma↗
PubMed1998

Primary intestinal non-Hodgkin's lymphoma and Epstein-Barr virus: high frequency of EBV-infection in T-cell lymphomas of Mexican origin.

Epstein-Barr virus is universally associated with endemic Burkitt's lymphoma (BL) and undifferentiated nasopharyngeal carcinoma and can be detected in a significant proportion of cases of Hodgkin's disease (HD) and peripheral T-cell lymphoma, but only rarely in sporadic B-NHL. The frequency of EBV-positivity in certain neoplasms shows important geographic variations. Both HD and sporadic BL from Latin America have shown higher rates of EBV-association than cases from Western countries. In T-NHL, the frequency of EBV-positivity is influenced by the site of the primary tumor and the phenotype of the neoplastic cells. Nasal and nasal-type T-NHL, which show a T/NK-cell phenotype with expression of CD56 are virtually always EBV-associated, whereas only a proportion of nodal, gastrointestinal and pulmonary T-NHL are EBV-infected. A recent investigation of primary intestinal lymphomas of Mexican origin demonstrated EBV-positivity in all examined cases of T-NHL and BL and a proportion of other B-NHLs. The presence of EBV was independent of the presence or absence of enteropathy. Two of 6 cases studied showed CD56 expression. The high rate of EBV-positivity independent of histologic subtype is in contrast to the low to intermediate rates of EBV-positivity found in cases of intestinal T-NHL from Western countries and indicates that geographic differences in the frequency of EBV-association of lymphoid neoplasms might also extend to a fraction of peripheral T-cell lymphomas.

Burkitt Lymphoma↗
PubMed1998

Post-transplantation lymphoproliferative disorders in Mexico: an aggressive clonal disease associated with Epstein-Barr virus type A.

Post-transplantation lymphoproliferative disorders (PT-LPDs) are a complication of immunosuppression with variable clinical behavior and frequent Epstein-Barr virus (EBV) association. There is geographic variation in the association of EBV with certain tumors and a lack of studies of PT-LPDs from developing countries, so we decided to study in detail a series of PT-LPDs from Mexico to identify similarities and differences between populations in Mexico and those in Europe and the United States. We used paraffin-embedded tissue from eight PT-LPDs (six from men, two from women) that arose after renal transplantation. Clinical data, morphologic features, and clonality on the basis of immunoglobulin (Ig) light chain restriction, as well as polymerase chain reaction (PCR) for Ig heavy chain genes, were studied. The presence of EBV was investigated with PCR, immunohistochemical analysis for latent membrane protein (LMP)-1, and in situ hybridization for EBV early RNA transcripts. In addition, the subtype of EBV based on the EBNA 2A and 2B genes and the presence of a 30-bp deletion in the LMP-1 gene were investigated by PCR. Seven (87.5%) of eight cases presented with gastrointestinal involvement; five patients died. Three cases were polymorphic PT-LPDs, four were monomorphic large cell lymphomas (one diffuse large cell, three immunoblastic), and one was unclassifiable. All showed a B-cell phenotype, with a clonal population demonstrated in seven of the eight cases. Tumor cells expressed EBERs in all of the cases and LMP-1 in six of seven evaluable cases. Seven of seven cases showed EBV subtype A. Two (25%) of eight cases had the 30-bp LMP-1 deletion. This study shows that PT-LPDs in Mexico are clonal disorders associated with EBV subtype A. In contrast to series from Europe and the United States, our cases showed a significantly higher incidence of gastrointestinal tract involvement (P < .001), and a lower incidence of the 30-bp LMP-1 deletion, although this was not statistically significant (P < .28).

Adult↗
PubMed1997

Primary non-Hodgkin's lymphoma of the intestine: high prevalence of Epstein-Barr virus in Mexican lymphomas as compared with European cases.

Recent studies in Western European populations have shown that peripheral T-cell non-Hodgkin's lymphomas (T-NHLs) are associated with Epstein-Barr virus (EBV) in a higher percentage than sporadic B-cell NHL (B-NHLs), and that the frequency of EBV-positivity might be influenced by the primary site of the tumor. Because of the geographic differences in EBV expression in Burkitt's lymphoma (BL) and Hodgkin's disease (HD), and the lack of studies of sporadic NHL from developing countries, we decided to survey the presence of EBV in a series of primary intestinal lymphomas from patients in Mexico and in Western Europe, and to analyze whether EBV status is influenced by tumor phenotype, and geographic or ethnic determinants. Paraffin-embedded tissue from 43 primary intestinal NHLs (19 cases from Mexico and 24 from Western Europe) were examined, including 17 high grade B-NHLs, 9 low grade B-NHLs, and 17 T-NHLs; 6 of which were enteropathy associated T-cell lymphomas. The distribution of histologic subtypes was similar in both groups. The presence of EBV was investigated with a combined approach using a nested polymerase chain reaction technique as well as immunohistochemistry for latent membrane protein-1 and in situ hybridization for EBV early RNA transcripts (EBER 1/2) RNAs. The median age of the Mexican patients was significantly lower than the median age of the European patients (32 v 62 years). This difference was most pronounced in patients with T-cell lymphoma (24 v 63 years). EBER-positive tumor cells were detected in 13 of the 43 (30%) cases of primary intestinal lymphoma, including 5 of 26 sporadic B-NHL (3 high grade and 2 low grade), and 8 of 17 T-NHL, all of which were classified as pleomorphic, medium and large cell. The rates of EBV-positivity were markedly different for European and Mexican cases. Whereas 7 of 7 (100%) T-NHL and 5 of 12 (42%) sporadic B-NHL of Mexican origin were EBER-positive, only 1 of 10 T-NHL and 0 of 14 sporadic B-NHL from Europe showed EBER expression in tumor cells. Latent membrane protein was positive in only 2 of 43 cases, 1 of which was an EBER-negative high grade B-NHL from Mexico that showed intact total mRNA in control hybridization. CD30 expression was found in 4 of 8 EBV-positive T-NHL and in none of the EBV-positive B-NHL. In contrast to European cases, intestinal NHLs from Mexico show a very high frequency of EBV-positivity, which is not limited to T-NHL, but includes a significant proportion of B-NHL. This study strongly suggests that similar to HD and probably BL, there are important epidemiologic differences in EBV association in intestinal T-cell NHL between European and Mexican populations. These differences might be the result of environmental factors, for example, earlier contact with childhood viruses on intestinal lymphomagenesis.

Adolescent↗
PubMed1997

Efficacy of fine-needle aspiration biopsy of thyroid nodules: experience of a Mexican institution.

In most centers only selected patients with high risk thyroid nodules undergo thyroid surgery, and fine needle aspiration biopsy (FNA) is used to select patients for surgical treatment. The aim of the present study was to evaluate the impact of FNA on the management of thyroid nodules at our institution. A total of 872 patients who underwent FNA over a period of 7 years were retrospectively analyzed. There were 66 men and 806 women with a mean age of 40 +/- 15 years. Altogether 549 patients presented with a thyroid nodule and 323 with multinodular disease. The sensitivity and specificity of FNA were 90.0% and 99.8%, respectively. The positive and negative predictive values were 98% and 99%, respectively, and the accuracy was 99%. Our results are in agreement with those of other reports establishing that FNA of the thyroid is safe, reliable, and effective for differentiating benign from malignant nodules.

Adolescent↗
PubMed1996

Papillary thyroid carcinoma in Mexican patients: clinical aspects and prognostic factors.

The present study characterizes papillary thyroid carcinoma (PTC) in a Mexican patient sample and evaluates potential prognostic factors for recurrence. Clinical records of 229 patients with PTC were analyzed. Surgical specimens were rereviewed and DNA ploidy determined. Cox logistic regression was used to explore prognostic factors. Mean age +/- SD of the patients was 42 +/- 16 years, with a male/female ratio of 24:205. A thyroid mass was the initial manifestation in 99%. Extrathyroid invasion occurred in 45% and nodal metastases in 38%. Mean size +/- SD of the tumors was 3 +/- 2 cm. By flow cytometry 88% of the tumors were DNA euploid and 12% aneuploid. Complete tumor resection was achieved in 83% with an operative mortality of 0.4%. Postoperative hormone suppression was administered in 65% and remnant 131I thyroid ablation in 84%. The 10-year recurrence-free survival was 85%. In the group of patients with tumors totally removed and without distant metastases, none of the 14 evaluated variables demonstrated statistical significance as an independent prognostic factor for recurrence. However, the group of patients in whom a combination of the following factors was present--age > or = 40 years, tumor size > or = 3 cm, local invasion, and lymph node metastases--showed a higher incidence of tumor recurrence.

Adult↗
PubMed1995

Gastrinoma of the common bile duct: immunohistochemical and ultrastructural study of a case.

Primary endocrine neoplasms of intra- and extrahepatic biliary ducts are very rare. We describe the first case of a primary endocrine tumor of the common bile duct producing gastrin. A 53-year-old woman had a 3-year history of recurrent duodenal and gastric ulcers as well as obstructive jaundice. A small neoplasm was found in the lower third of the common bile duct, which showed diffuse gastrin production and focal synthesis of serotonin and pancreatic polypeptide by immunohistochemistry and electron microscopy. Although serum gastrin was within normal levels (90 ng/ml), symptoms of peptic acid disease could have been related to hypergastrinemia, since gastric and duodenal ulcers healed after surgical removal of the tumor. She has remained asymptomatic for 8 months.

Cholestasis↗
PubMed1995

Association of Epstein-Barr virus latent membrane protein and Hodgkin's disease in Mexico.

Epstein-Barr virus (EBV) has been demonstrated in association with Hodgkin's disease (HD) in approximately 40 to 50% of cases in series from North America, Europe, and Japan. However, few data are available concerning this association in developing countries. Recent studies, including mostly a pediatric population from Peru and a pediatric population from Honduras, showed a higher percentage of EBV positivity compared with those in developed countries. To determine the prevalence of EBV in Hodgkin's disease in a Mexican adult population, we analyzed 50 formalin-fixed, paraffin-embedded cases of HD by a three-step technique using a monoclonal antibody to the latent membrane protein of EBV. All the cases were confirmed immunophenotypically as HD (CD15+ and/or CD30+, CD45-). Reed-Sternberg cells and variants were positive for LMP in 35 cases (70%). The staining was found both on the cell surface and/or within the cytoplasm with enhancement of the Golgi area. EBV latent membrane protein was found in 1/1 case (100%) of diffuse lymphocyte-predominant HD, 10/20 cases (50%) of nodular-sclerosis, 18/22 cases of mixed-cellularity (81%), and 6/7 (86%) cases of lymphocyte-depleted HD. Our results show a high prevalence of EBV in HD in this Mexican adult population. All histologic subtypes of HD in the population analyzed appear to be strongly associated with EBV, in contrast to the strong association of mixed cellularity HD in developed countries. Patient age and gender were not predictive of the presence of EBV.

Adolescent↗
PubMed1991

Primary carcinoid of the common bile duct. Immunohistochemical characterization of a case and review of the literature.

A 39-year-old woman with a primary carcinoid of the common bile duct is presented. The tumor showed argyrophilia; and, by immunohistochemical studies, chromogranin, serotonin, and somatostatin were demonstrated. The patient has no symptoms 42 months after surgical treatment. To the authors' knowledge, this is the first report of a carcinoid of the common bile duct as studied by immunohistochemistry. When six choledochal carcinoids were reviewed, the following characteristics were observed: in none of the cases were endocrine symptoms present; women were affected more frequently than men; the carcinoids occurred in younger patients than did adenocarcinomas; metastases were present in half of the patients; and, as a group, carcinoids seemed to have a better prognosis than adenocarcinomas in this location.

Adult↗
PubMed1990

Comparative demographic and autopsy findings in acquired immune deficiency syndrome in two Mexican populations.

In order to identify the characteristics of the acquired immune deficiency syndrome (AIDS) as it occurs in Mexico, a comparative study of the demographic and pathological findings of the first 58 patients who died of AIDS and were autopsied at two Mexican hospitals, Hospital General de Mexico (HG) and Instituto Nacional de la Nutricion (INN), was performed. The patient population consisted of 52 men and 6 women. Their socioeconomic status (SES) was estimated using the occupational prestige and level of education as indicators. As in the U.S.A., most patients (72%) were male homosexuals/bisexuals (HMS/BSX). However, nine patients (31%) at the HG could not be assigned to any of the currently known risk groups. Comparison of the SES of the two series revealed a significantly higher number of poor patients at HG (81 vs. 17%). For the whole group, the most frequent infections were caused by cytomegalovirus (CMV) (65%), Mycobacterium tuberculosis (28%), Pneumocystis carinii (24%), and Toxoplasma gondii (17%). Kaposi's sarcoma (KS) was found in 41% of the cases. The frequency of toxoplasmosis was higher in poor patients (30 vs. 8%, odds ratio of 5.5, 95% confidence limits of 0.83, 39.34, p = 0.04) while the reverse situation was true for KS (18 vs. 61%, odds ratio of 0.14, 95% confidence limits of 0.04, 0.55, p = 0.001). For KS, this difference persisted when only HMS/BSX patients were compared. In conclusion, dissimilarities observed in the frequency of some AIDS-associated diseases in different institutions appear to be mainly influenced by the SES of the patients.

Acquired Immunodeficiency Syndrome↗