Biomedical subjects

I Roa

Publications and source records attributed to I Roa.

At least 73 records · Page 4Linked to original sources

PubMed1992

[Gastric cancer: epidermal growth factor and epidermal growth factor receptor].

In 19 patients with advanced gastric cancer the expression of epidermal growth factor receptor and epidermal growth factor (EGF) were studied using immunohistochemical techniques. There were 12 males and the mean age of the group was 54.8 years. Most cases belonged in Borrmann's types III or IV. Tumoral cells were positive for EGF receptor in 9 patients (47%), with a strong reaction in 6. Thirteen of 18 subjects were positive for EGF. The reaction for EGF receptor was positive in 20% of 12 patients with intestinal type tumors and in 67% of 7 patients with diffuse tumors. Reaction for EGF was positive in 80% of intestinal type tumors and 64% of diffuse tumors. Simultaneous positive reactions for both antigens was observed in 5 of 18 patients, all with diffuse type tumors. Signet ring cell tumors showed less positivity than less differentiated ones. Thus, the expression of EGF and EGF receptor was higher in our patients with advanced gastric cancer than reported elsewhere.

Adult↗

PubMed1992

[Characteristics of gastric cancer in the IX region of Chile].

The results of a prospective protocol for the management of patients with gastric cancer applied from May 1988 to June 1991 are reported. 123 patients were operated on and a resection performed in 55%. Only 14 patients had incipient tumor and 44 had "curative" surgery. There was a preponderance of non differentiated tumors located high in the stomach. Endoscopy and biopsy were performed in cases with positive diagnosis in 91 and 93%, respectively. The overall actuarial survival rate was 37% at 38 months, rising to 50% for patients undergoing resection and to 82% in patients with "curative" resection.

Adult↗

PubMed1992

[Gallbladder cancer: immunohistochemical expression of CA-19-9, epithelial membrane antigen, dupan-2 and carcinoembryonic antigen].

The immunohistochemical expression of CA19-9, epithelial membrane antigen (EMA), and carcinoembryonic antigen (CEA) was studied in 103 tissue samples of gallbladder cancer and 25 samples of non tumoral gallbladder lesions. CA19-9 and EMA were positive in over 90% of cancers and non tumoral lesions. Dupan-2 expression was observed in 100% of non tumoral lesions and 78% of cancers. CEA expression was observed in 12% of non tumoral lesions and 89% of cancers. The magnitude of immunohistochemical staining was moderate or intense for all antibodies, except Dupan-2. No differences were observed in the location of positive staining in superficial or deep parts of the tumor. In these lesions the positive staining was cytoplasmatic with a granular and irregular pattern; on the contrary, in the non tumoral lesions, staining was seen in the apical parts of the cell. Calculated sensitivity, specificity and positive predictive value for CEA was 89%, 88% and 96% respectively. If future studies disclose a good correlation between serological and immunohistochemical detection of this antigen, its determination would be potentially useful in clinical grounds.

Antigens, Neoplasm↗

PubMed1992

[Immunohistochemical demonstration of pepsinogens I and II in the gallbladder].

The immunohistochemical expression of pepsinogen I (PI) and pepsinogen II (PII) was studied in 103 gallbladder carcinomas, 25 non tumoral gallbladder lesions and 23 gallbladder cancer metastases. PI was positive in 6% of carcinomas and only in 2% of non tumoral contiguous mucosa. PII was positive in 46% of carcinomas and 43% of controls. Metastases were negative for both enzymes. Pyloric gland metaplasia of non tumoral mucosa adjacent to the tumor expressed PII in 68.9% and PI in 3.4% of cases. The same lesion in non tumoral gallbladders was positive for PII in 66.6% of cases, and no case expressed PI. There was no relationship between PI expression and the histological degree of differentiation. Only tumors with serosal or subserosal involvement were positive for PI. PII had a higher expression in early or well differentiated tumors. Tumors with pyloric gland metaplasia in the contiguous non tumoral mucosa expressed PII more frequently. Our results, based on the expression of PI and PII, suggest a relationship between the presence of pyloric gland metaplasia and some types of gallbladder cancer.

Biomarkers, Tumor↗

PubMed1991

Pathological features of renal cell carcinoma incidentally discovered at autopsy.

Renal cell carcinomas incidentally discovered at autopsy (IRCs) were retrospectively analyzed to determine whether they had any pathological features differing from clinical renal cell carcinomas (CRCs): From 7,970 autopsy cases, there were 51 cases (0.65%) of renal cell carcinoma (RC) including 42 men and 9 women (ratio 4.6:1). The mean age of RC cases was 66.3 +/- 12.9 (range of 20 to 91 years). Of the 51 RC cases, approximately half of them (25/51) were IRC cases. No difference was shown in age and sex between IRC and CRC cases. Mean tumor size of IRC was 2.6 +/- 2.5 cm in diameter. This was significantly smaller (P less than 0.01) than that of CRC (7.3 +/- 2.8 cm). Histologically, both grade 1 and clear cell type were significantly more predominant among IRC cases than CRC cases (P less than 0.01 and P less than 0.05, respectively). Only one out of 25 cases of IRC had distant metastasis, as compared to 23 out of 26 CRC cases (88.5%). These pathological features indicate that the incidentally discovered renal cell carcinoma may have less malignant potential than clinical tumors. Unexpectedly, the majority of the IRC cases (88.0%) were associated with advanced neoplasia of other sites, as compared to only 19.0% of CRC cases (P less than 0.01).

Adult↗

PubMed1991

[Immunohistochemical expression of the carcinoembryonic antigen in gallbladder cancer].

Immunohistochemical techniques using monoclonal antibodies were used to investigate the carcinoembryonic antigen (CEA) in gallbladders from 26 patients with gallbladder cancer and 26 patients without cancer, including normal mucosa, areas of pyloric metaplasia and areas identified by the presence of "clear cells". All carcinomas were strongly positive for CEA but 61% of noncancerous samples were also positive. However, only 1 of the last samples was strongly positive. According to histologic type the positivity for CEA in noncancerous samples was 6/11 in normal mucosa, 6/8 in samples with intestinal metaplasia and 1/8 in samples with pyloric metaplasia (p less than 0.05). Thus a negative reaction for CEA is 100% specific for absence of cancer. If mild reactions are disregarded, a strong reaction for CEA is 81% specific for cancer.

Antibodies, Monoclonal↗

PubMed1991

[Stomach neoplasms in the IX Region of Chile: comparison of the anatomo-pathological study of lymph node emptying in 2 periods].

Complete resection of lymph nodes may help achieve a cure in patients with gastric cancer. In this paper we evaluate the yield of a careful search for lymph nodes in fresh tissue obtained immediately after resection. A mean of 42.5 nodes per gastric piece was obtained, which is significantly higher than that previously reported with examination of fixed tissue. The yield was higher for all node groups except the left para-cardial one.

Carcinoma↗

PubMed1991

[Advanced stomach neoplasms: expression of the fixation index of bromodeoxyuridine in vivo].

We studied fixation of bromodeoxyuridine by immunohistochemistry in 17 patients with advanced gastric cancer. Macroscopically, they corresponded to Borman's types III (n = 10), IV (5) I (1) and unclassified (1). 11 patients had a diffuse lesion, 5 an intestinal type lesion and 1 an epidermoid carcinoma. Positive reactions were observed in 27.7% of cells (95% CL 10-48%). No difference was observed in positivity of superficial (29%) or deep areas of the tumor (27%). Greater fixation rates were observed in patients under 50 years, of age compared to older patients. The percentage of positive reactive cells was not related to macroscopic or histologic tumor type. Greater fixation rates were observed in this series compared to those previously reported, suggesting greater proliferation rates in these patients.

Adenocarcinoma↗

PubMed1991

[Nucleolus organizer regions and ploidy pattern of DNA in stomach neoplasms].

We studied 20 gastric adenocarcinoma to determine DNA ploidy pattern by flow cytometry and nucleolar organizer regions by the colloidal silver method. There were 12 diffuse and 8 intestinal type lesions. 11 tumors were classified as diploid and 9 as aneuploid. No correlation was observed between DNA ploidy pattern and mean number of nucleolar organizer regions. The histologic type was significantly related to the number of nucleolar organizer regions (p < 0.01). Poorly differentiated lesions had significantly less nucleolar organizer regions than intestinal type lesions. Lesions with ring cells (n = 6) had similar number of nucleolar organizer regions than poorly differentiated lesions.

Adenocarcinoma↗

PubMed1991

[Inapparent cancer of the gallbladder].

Gallbladder cancer is the most common cancer in the Chilean female population. A prospective histological mapping of cholecystectomy pieces allowed the detection of 37 tumors not evident to the surgeon. Tumoral invasion engaged the mucous membrane in 7, the muscular layer in 8, the subserous layer in 12, the serous membrane in 5 and the surrounding adipose tissue of the gallbladder in 5 cases. 18 pts were reoperated on for resective oncological surgery. In 5 of these cases the ganglia, and in 6 the hepatic tissue behind the gallbladder were involved. Actuarial survival at 38 months was 48% (10 pts have died by the time of this publication). The prognosis of the disease was directly related to histological differentiation and to the degree of tumoral invasion. Gallbladder cancer has a poor prognosis even if the surgeon has no suspicion of the disease and a simple cholecystectomy is by no means a healing therapy.

Adult↗

PubMed1991

[Lithiasis of gallbladder in the IX region. Study of the autopsies in a zone with a high proportion of Mapuche population].

The frequency of gallbladder stones in he IXth Region of Chile with a large indigenous population, was studied in forensic necropsies from 1980 to 1989. Among 2,505 autopsies, 85% were males and 15% females. At least 1 "mapuche" surname occurred in 27% of cases. Stones were found in 34% of females and 12.7% of males. No differences were found between "mapuche" and non mapuche cases. Cholecystectomy had been performed in 2.3% of males and 9.1% of males. These results do not differ from those reported from other regions in Chile.

Adolescent↗

PubMed1990

Operative findings in patients with early forms of gallbladder cancer.

Of 52 patients diagnosed as having gallbladder cancer in a 2-year period, 15 had no evidence of serosal involvement. Four of these 15 patients had tumour confined to the mucosa and did not undergo reoperation while 11 patients underwent lymph node dissection and hepatic wedge resection at a second operation. The correct diagnosis was suspected before the first operation in only one of 11 patients undergoing reoperation; the tumour was found microscopically in seven patients. Of the 11 patients who underwent reoperation, five had lymph node involvement, and three of these patients had both liver and lymphatic involvement. Our results underline the difficulty of establishing the diagnosis of gallbladder cancer before operation and the lack of major morbidity and mortality suggests that there may be value in reoperating on patients found to have gallbladder carcinoma without serosal involvement. Further follow-up is required to assess the long-term value of this approach.

Adult↗

PubMed1990

Peripheral pigmented neuroectodermal tumor of infancy with rhabdomyoblastic differentiation.

A case of a 6-month-old male with a peripheral pigmented neuroectodermal tumor of the right popliteal region is presented. The tumor disclosed neuroblast-like and melanoblast-like cells and on electron microscopy tumor cells with rhabdomyoblastic differentiation. The patient is well and alive and without evidence of disease three years after the initial diagnosis. This unusual case gives further support to the current theory of a common origin for central and peripheral neuroectodermal neoplasms and related entities.

Cell Transformation, Neoplastic↗

PubMed1990

[In situ and invasive cancer of the gallbladder: nucleolar organizer regions].

We studied samples from gallbladders of 10 subjects with invasive and 10 with in situ carcinoma of this organ. The number of nucleolar organizer regions, as revealed by colloidal silver staining, was at least 4 times larger in cancer samples than in control ones. Mean number of nucleolar organizer regions for invasive lesions was higher than for in situ ones (11.6 +/- 2.3 vs 9.4 +/- 1.3, p less than 0.04). The study of cellular markers may be helpful in establishing the preneoplastic nature of gallbladder lesions.

Adenocarcinoma↗

PubMed1990

[Neoplasms of Vater's papilla: study of nucleolar organizer regions].

We analyzed the number and aspect of nucleolar organizer regions in 11 specimens from ampullary carcinoma, by means of silver colloidal staining. The number of regions was higher than that found in intestinal villi but similar to that in cripti. The size of the regions was larger than any of those mentioned above. These elements may contribute to evaluate endoscopic samples in the diagnosis of ampullary lesions.

Adult↗

PubMed1990

[Association of gallbladder and Vater's ampulla neoplasms. Report of a case].

A 54 year old female was operated on for ampullary carcinoma diagnosed by retrograde cholangiography. Histologic study of the gallbladder resected at operation revealed another carcinoma at that location. Pancreato-duodenectomy plus a double segmental resection of liver was performed. The patient remains in good condition 11 months after operation.

Adenocarcinoma↗

PubMed1990

[The pathological findings in patients reoperated on for gallbladder cancer].

We reviewed the pathological data from 20 patients who were reoperated on for gallbladder cancer. Diagnosis was made in all from the histological analysis of the removed gallbladder. Mean age was 54. Tumor infiltration extended to the muscular layer in 6, to the subserosa in 9 and to the serosa in 5 patients. At surgery, local hepatic resection and lymph node dissection were performed. Tumoral involvement was limited to the liver in 2 patient, to lymph nodes in 3 and extended to both in the remaining. The first lymph node barrier was involved in 40%, the second in 15% and the tumor extended to the third barrier in 10%. These data suggest that hepatic and lymph node involvement occur early in gallbladder cancer and explain the poor prognosis of this malignancy.

Adult↗

PubMed1990

[Gallbladder cancer: anatomic and anatomo-pathologic considerations].

Gallbladder cancer is a common neoplasia in Chile. Subclinical forms constitute 30 to 50% of all cases and poorly differentiated lesions are more common in Chile than elsewhere. Traditional grading of this neoplasia according to the degree of wall infiltration neglects important aspects such as the discontinuity of the muscular layer, heterogeneity of the subserosa, microinvasion of the mucosa and Rokitansky-Aschoff sinuses. All of these factors may influence prognosis. Surgical biopsy of liver and lymph nodes in cases without infiltration of the mucosa has revealed up to 60% rate of hepatic infiltration and a somewhat lower on for lymph nodes. We have designed a study that will evaluate the importance of all these factors in the prognosis of gallbladder cancer in our institution.

Adenocarcinoma↗