PubMed Health⌕ Search

Biomedical subjects

M A Marcial

Publications and source records attributed to M A Marcial.

At least 19 recordsLinked to original sources
PubMed1996

Gastric fundic gland polyps: a morphological study including mucin histochemistry, stereometry, and MIB-1 immunohistochemistry.

Fundic gland polyps are benign lesions, composed of a disorderly arrangement of normal gastric corpus cell types, that occur in a large proportion of patients with familial adenomatous polyposis (FAP) but also develop sporadically in non-FAP patients as well. In this study, the authors evaluated and compared the endoscopic, histological, mucin histochemical, and microscopic stereologic features of 77 fundic gland polyps (FGPs) (15 FAP; 62 non-FAP) to determine if FAP-associated and sporadic lesions are histologically distinct. The authors also analyzed the distribution of mitotically active cells and smooth muscle cells in these lesions using MIB-1 and smooth muscle alpha-actin immunohistochemistry in an effort to determine the pathogenesis of these lesions. The results show that, compared with non-FAP cases, FAP patients with FGPs have a lower male-to-female ratio, a younger mean age at diagnosis, and a higher proportion of cases with multiple polyps. However, no differences were detected between FAP and non-FAP-associated FGPs with respect to any endoscopic, morphological, mucin histochemical, or stereometric features. Eighty-six percent of FGPs showed an increase in smooth muscle content, often in a pericystic distribution. MIB-1-positive proliferative cells were observed not only in the foveolar stem cell region, as expected, but also in the epithelium lining the microcysts and in the gland buds located directly adjacent to the microcysts. The authors conclude that FAP and non-FAP-associated FGPs are histologically identical, and propose that proliferation and subsequent differentiation of aberrantly located proliferative cells in these lesions may explain the histogenesis of FGPs.

Adult↗
PubMed1995

Pathology of androgen deprivation therapy in prostate carcinoma. A comparative study of 173 patients.

BACKGROUND: Leuprolide, an agonist of luteinizing hormone-releasing hormone (LH-RH), and flutamide, an antiandrogen, increasingly are being used in the treatment of clinically localized prostate cancer. Only two small series (of 23 and 12 patients) have been published on the distinctive pathologic changes induced in the prostate by androgen deprivation therapy with discrepancies on the presence of squamous metaplasia, necrosis, and possible tumor destruction by combined androgen deprivation therapy. METHODS: One hundred and thirteen radical prostatectomy specimens obtained after at least 3 months of leuprolide-flutamide androgen inhibition therapy and 60 nonhormonally treated prostates in randomly selected clinical Stage T2 prostate adenocarcinoma patients were entirely sectioned. Distinctive histologic findings were tabulated and their statistical value determined. RESULTS: Resection margins of excision were involved by tumor in 43% of untreated and in 19% of androgen-deprived patients. Characteristic changes in androgen-inhibited nontumor glands included atrophy, basal cell prominence, vacuolated luminal cell layer, and squamous and transitional cell metaplasia. Prostatic intraepithelial neoplasia (PIN) was observed in 35% of treated patients. The presence of small tumor glands separated by stroma was the most frequently noted effect of androgen deprivation on prostate adenocarcinoma; pyknosis and branching empty spaces were less frequent. Large clear tumor cells within an inflammatory response was a third histologic pattern. Apparently unaltered tumor areas were observed in 43% of prostates exposed to androgen deprivation therapy. CONCLUSIONS: Androgen deprivation therapy results in histologically distinctive changes that can be recognized in both nonneoplastic and neoplastic prostate tissue. Residual tumor was present in all 113 treated radical prostatectomy specimens. In addition to glandular shrinkage, therapy was associated with statistically significant reductions in the frequency of high grade PIN and extension of cancer to prostate specimen margins of excisions.

Androgen Antagonists↗
PubMed1995

Endometriosis of the appendix with decidual polyp formation: a rare cause of acute appendicitis during pregnancy.

We report a case of a 28-year-old female, Grava 2, Para I, Ab. 0, who presented acute abdominal pain on the 21st week of her gestation. A diagnosis of acute appendicitis was entertained and an appendectomy performed. The pathologic specimen revealed an inflamed appendix with endometriosis and a marked decidual reaction. A decidual polyp, which occluded most of the appendiceal lumen, is proposed as a rare cause of acute appendicitis during pregnancy.

Abdomen, Acute↗
PubMed1994

Adult paratesticular tumors: report of two cases.

Paratesticular tumors are uncommon tumors, most being found incidentally at autopsy. The most common benign paratesticular tumor is the adenomatoid tumor. A somewhat less frequent benign paratesticular tumor, papillary cystadenoma, accounts for approximately 33 percent of all the primary epididymal tumors and is frequently seen in patients with Von Hippel-Lindau disease. Malignant tumors are rare. Of these, rhabdomyosarcoma is the most frequent. Seen almost exclusively in the pediatric population, paratesticular rhabdomyosarcomas account for 7 percent of childhood rhabdomyosarcomas. We describe two cases of paratesticular tumors in adults: a papillary cystadenoma of the epididymis in a 72-year old male, and an incidental rhabdomyosarcoma in a 49-year old male.

Aged↗
PubMed1993

Fundic gland polyps: prevalence and clinicopathologic features.

We evaluated prospectively all gastroscopic examinations performed at two institutions for a period of 24 months with the aim of studying fundic gland polyps in our patient population. Forty-four patients with fundic gland polyps of the stomach were identified among 5554 patients who underwent endoscopy, for a prevalence of 0.8% in our patient population. Twelve additional patients with fundic gland polyps were identified through our surgical pathology referral practice. The patients' ages ranged from 27 to 82 yr, with an average age of 53 +/- 13 yr. The vast majority of the patients were female, with a female-to-male ratio of approximately 5:1. The polyps averaged 2.3 +/- 1.2 mm in size. An average of four polyps per patient were seen, with a range of one to 11.

Adult↗
PubMed1993

Colorectal carcinoma: a pathologic and immunopathologic study.

Lewis-related blood group antigens are carbohydrate determinants carried on surface glycoproteins and glycolipids of erythrocytes and some epithelial cells. Their expressions in colorectal mucosa has been considered either as a marker of differentiation antigens or of tumor associated antigens. We prospectively studied Lewis-related blood group antigens in patients undergoing colectomy for colonic adenocarcinoma. Immunohematological studies were performed on preoperative blood samples and ABO and Lewis blood groups were determined. Tissue samples were obtained from the adenocarcinoma and from the adjacent non-neoplastic mucosa. The degree of tumor differentiation (grade of the tumor) was analyzed on hematoxylin and eosin stained slides. Immunoperoxidase staining was performed using antibodies against A, B, Le(a), Le(b), Le(x), and Le(y) antigens. The staining results of the colonic carcinoma were compared with those of the non-neoplastic mucosa and with the patient's red blood cell Lewis phenotype. A total of 22 patients were studied, 12 males and 10 females, with an average age of 64 +/- 12 years. There were 12 modified Dukes B and 10 modified Dukes C carcinomas. Le(a), a marker of differentiation antigens, was expressed in the non-neoplastic mucosa of 82% of the specimens. Le(y), a marker of tumor associated antigens, was detected in 77% of the carcinomas while expressed only in 18% of the adjacent non-neoplastic mucosa. Le(x), supposedly a marker for tumor aggressiveness, was found in 55% of the carcinomas. However, it was virtually absent in the five carcinomas which did not invade the pericolic tissues.

Adenocarcinoma↗
PubMed1993

Pathology of pulmonary hypertension and schistosomiasis mansoni.

We report a case of a 33-year-old woman with grade IV pulmonary hypertension and end stage cor pulmonale secondary to chronic schistosomiasis (bilharziasis). The pathophysiology and morphologic features are discussed. Schistosomiasis is an important etiology to consider in the differential diagnosis of pulmonary hypertension.

Adult↗
PubMed1990

Gastric campylobacter-like organisms and active antral gastritis in Puerto Rico.

We attempted to verify if the reported association of gastric campylobacter like organisms (GCLO) with active antral gastritis holds true in our population. All patients undergoing elective upper endoscopy were eligible for the study unless they had a history of gastric cancer or previous antrectomy. Biopsy specimens from 100 consecutive patients were examined blindly for the presence of inflammatory activity and/or intestinal metaplasia. The presence of GCLO was determined by the acridine orange fluorescence technique. A total of 131 antral biopsies examined were classified as either normal, active gastritis, chronic gastritis with activity and chronic gastritis without activity. GCLO were identified in 84% of the biopsies with inflammatory activity (active gastritis and chronic gastritis with activity). However, GCLO were found only in 11% of those biopsies with chronic gastritis without activity. It is therefore our conclusion that the previously reported association of GCLO with active gastritis holds true for our population.

Biopsy↗
PubMed1989

Serum cholesterol levels in Puerto Rican volunteer blood donors.

The blood samples of four hundred and fifty eight healthy volunteer blood donors were analyzed to determine their serum lipid profile. Based on these lipoprotein analyses, it was concluded that approximately 12% of the sampled population was in a high risk group for coronary heart disease.

Blood Donors↗
PubMed1989

Biliary tract disease due to Fasciola hepatica: report of a case.

We report a case of a 23 year old woman who presented with symptoms of biliary tract disease to our University Hospital in Bayamón, Puerto Rico. A diagnosis of chronic cholelithiasis was made and the patient was taken to surgery. An adult Fasciola hepatica was recovered from the common bile duct. We review the pathobiology of this uncommon zoonosis.

Adult↗
PubMed1987

Structural features of the apical and tubulovesicular membranes of rodent small intestinal tuft cells.

Tuft cells are present in most columnar epithelia derived from endoderm including the small intestine. They are characterized by long, wide apical microvilli and an extensively developed cytoplasmic tubulovesicular system. We examined in detail the structural features of the apical plasma membrane of small intestinal tuft cells from adult guinea pigs, rats, and adult and suckling mice with freeze-fracture and conventional transmission electron microscopy methods and utilized cationized ferritin and horseradish peroxidase as tracers to determine whether tuft cells endocytose macromolecules. The microvillus membrane of intestinal tuft cells has few P-face intramembrane particles, displays little alkaline phosphatase activity, and is highly enriched in cholesterol. Tuft cell tight junctions resemble those of absorptive cells in strand count and strand-to-strand crosslinks but, unlike those of absorptive cells, they display many abluminal free-ending strands. Tuft cells of adult and suckling mouse intestine show no evidence of internalization of cationized ferritin or, in suckling mice, uptake of horseradish peroxidase. We conclude that the microvillus membrane of small intestinal tuft cells is protein-poor but cholesterol-rich and that small intestinal tuft cells do not endocytose macromolecules in bulk from the intestinal lumen.

Animals↗
PubMed1987

Analysis of absorptive cell occluding junction structure-function relationships in a state of enhanced junctional permeability.

Junctional strand count, the number of individual junctional strands which intersect a perpendicular, has been widely used as a morphological estimate of the ability of an occluding junction to resist passive transjunctional molecular flow. Such junctional analysis, which requires the study of freeze fracture replicas, has been useful in studies of occluding junction structure function relationships in unperturbed epithelia and in intestinal epithelia under conditions which lead to increases in junctional resistance. It is unclear if the above junctional structure-function correlates also exist in intestinal or in other epithelia under conditions which result in a state of enhanced junctional permeability. To gain further insight into occluding junction structure-function relationships under such conditions, we utilized an in vivo hypertonic perfusion model previously shown to result in the transfer of luminal macromolecules into the paracellular space of small intestinal villus epithelium. After a 1-hour perfusion with either 600 mOsmoles or 750 mOsmoles mannitol solutions, the macromolecule horseradish peroxidase diffusely filled the paracellular spaces of the upper half of villi. However, analysis of thin sections showed that only junctions at the tip of villi were leaking this tracer. Freeze fracture analysis revealed occluding junction structural abnormalities most marked at the villus tip thus corresponding to the site of transjunctional horseradish peroxidase leak. The most frequent abnormality noted was loss of strand-strand crosslinking and dilation of the interstrand compartments. At such sites, wide unobstructed channels could be traced through much of the junction. However, the apical junctional strand was never noted to display unequivocal discontinuities. Subsequent in vitro studies of perfused tissues revealed that dose dependent decreases in transepithelial resistance and junctional charge selectivity were induced by hypertonic mannitol perfusions. These studies indicate that: paracellular localization of a luminally applied tracer may result from a transjunctional leak at a distant site with subsequent lateral diffusion of the marker; traditional junctional strand count-function relationships may not hold in states which lead to the rearrangement of junctional architecture; and, at least the apical junctional strand may become permeable to macromolecules without the introduction of morphologically detectable strand discontinuities as assessed by routine freeze fracture techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Intrahepatic biliary cystadenoma. Clinical, radiological, and pathological findings.

A 24-year-old white woman presented with abdominal discomfort associated with a firm, nonpulsatile hepatic mass. Radiological examination, which included radionuclide liver scan, abdominal ultrasonography, computed tomography, and hepatic angiography, demonstrated a large, globular, multilocular cyst arising from the left lobe of the liver. A left hepatic lobectomy was performed, and gross examination of the specimen confirmed the cystic nature of the lesion. Histologically, the multiple locules were lined by a single layer of tall cuboidal to columnar cells, which were comparable to those of native biliary tract epithelium. There was little evidence of cellular pleomorphism, and invasion into the underlying mesenchymal stroma was not present. A diagnosis of intrahepatic biliary cystadenoma was made. The clinical, radiological, and pathological findings of this neoplasm are presented and its differential diagnosis discussed.

Adult↗