Biomedical subjects

L A Guarda

Publications and source records attributed to L A Guarda.

At least 19 recordsLinked to original sources

PubMed2001

Down-regulation of prostasin serine protease: a potential invasion suppressor in prostate cancer.

BACKGROUND: Prostasin is a serine protease predominantly expressed in normal prostate epithelial cells. The biological function of prostasin has not been determined. METHODS: Western blot and RT-PCR analyses were used to examine the expression of prostasin in prostate cancer cell lines. Immunohistochemistry was used to evaluate prostasin protein expression in human prostate cancer. An in vitro Matrigel invasion assay was used to test the invasiveness of prostate cancer cell lines forced to express recombinant prostasin. RESULTS: Both prostasin protein and mRNA were found to be expressed in normal human prostate epithelial cells and a non-invasive human prostate cancer cell line, the LNCaP, but neither was found in invasive human prostate cancer cell lines DU-145 and PC-3. Prostasin mRNA expression was absent in invasive prostate cancer cell lines of a transgenic mouse model. Immunohistochemistry analysis showed that prostasin protein expression is down-regulated in high-grade prostate cancer. Transfection of DU-145 and PC-3 cells with a full-length human prostasin cDNA restored prostasin expression and reduced the in vitro invasiveness by 68 and 42%, respectively. CONCLUSIONS: Our data indicate that prostasin may be implicated in normal prostate biology and is able to suppress prostate cancer invasion in vitro.

Blotting, Western↗

PubMed1992

Simultaneous fine-needle aspiration of thyroid lesions and regional cervical lymph nodes: clinicopathologic implications.

Occasionally patients with thyroid nodules to be evaluated by fine-needle aspiration (FNA) biopsy also present with regional cervical lymphadenopathy. Aspiration biopsies should be performed on both the thyroid and nodal lesions. This approach will yield important information about whether the lesions are related, with profound impact on further workup, management, prognosis, and staging.

Aged↗

PubMed1991

Anaplastic thyroid carcinoma: cytomorphology and clinical implications of fine-needle aspiration.

Four cases of anaplastic carcinoma of the thyroid were diagnosed in 1,519 thyroid aspirates. All patients had unilateral or diffuse nodular enlargement of the thyroid. One patient had a concurrent grade 1 mucinous carcinoma of the ovary. Cytologically, the neoplasms were characterized by pleomorphic giant or spindle cells with multilobulated, single or multiple nuclei. The chromatin pattern was clumped with prominent parachromatin clearing, and there were multiple prominent nucleoli. Associated papillary and follicular structures were recognized in two aspirates. All cytologic preparations were considered diagnostic of malignancy. Examination of histologic material revealed the same elements identified cytologically on the aspiration smears. Three patients died shortly after diagnosis due to massive local tumor growth in the neck. One patient, who received radiation therapy, had a prolonged survival of 30 mo, but died then of local neck recurrence. The cytologic features of anaplastic carcinoma parallel their histologic appearance. Histologic confirmation of cytologically diagnosed anaplastic carcinoma is not necessary.

Adult↗

PubMed1990

Intraoperative cytologic diagnosis: evaluation of 370 consecutive intraoperative cytologies.

Three-hundred and seventy intraoperative cytologies are presented and compared with synchronously performed frozen sections. Cytologic smears and frozen sections were misinterpreted in 1.6% and 0.8% of cases, respectively; the rate of diagnostic errors between the two techniques is comparable given the lack of experience with intraoperative cytology at the beginning of the study. Intraoperative cytology is a suitable technique for a variety of lesions, but it is most helpful in the field of neuro-oncological pathology, certain infectious diseases, lesions of the hematopoietic system, and most epithelial tumors. Cytologic smears afford better morphologic preservation and detail than frozen sections. Techniques are outlined and discussed. Diagnostic criteria of selected cases are presented, and pitfalls are analyzed.

Brain Neoplasms↗

PubMed1990

Hand and digital ischemia due to arteriosclerosis and thromboembolization in young adults: pathologic features with clinical correlations.

Twenty young adult patients with hand and digital ischemia were found to have obstructive arterial disease. All patients were surgically explored, and the occluded vessels were resected and by-passed. Eighteen patients had obstruction at the level of the distal ulnar artery and palmar arch, and 12 had obstruction of the common digital and digital proper arteries. Occlusive arteriosclerotic lesions were found in all patients; these lesions were characterized by prominent fibromuscular intimal plaques with superimposed thrombosis. Six patients had also thromboembolism to distal digital vessels. Vasculitis, calcifications, cholesterol deposits, and atheromatous emboli were not observed. Five patients had transmural neovascularization of the lesions in a similar manner to that described in coronary artery lesions. Obstructive lesions due to fibromuscular intimal proliferation with associated thrombosis and/or distal thromboembolization affecting arteries of hands and digits appear to be an important lesion that can affect young patients.

Adolescent↗

PubMed1988

Cytology of pleural effusions in rheumatoid arthritis.

Rheumatoid pleural effusions are relatively uncommon. The cytologic examination of such effusions can be diagnostic of the underlying disease; this is of great clinical significance when the rheumatoid condition has not been diagnosed prior to the pleural involvement. The diagnostic cytologic abnormalities include large elongated and multinucleated giant cells and macrophages in a background of granular and necrotic debris. The cytologic characteristics parallel the histologic features of pleural rheumatoid nodules.

Adult↗

PubMed1987

Gangliocytic paraganglioma of the duodenum: report of cytologic, histologic, immunohistochemical, and ultrastructural features of a case.

A case of gangliocytic paraganglioma of the duodenum is reported, including light microscopic, ultrastructural, and immunohistochemical characteristics. The cytologic appearance, as might be seen in fine-needle aspiration smears, indicates a neoplasm with three cellular components (epithelioid, ganglion, and spindle cells) seen histologically by light and electron microscopy.

Duodenal Neoplasms↗

PubMed1987

Inflammatory and lymphoid lesions of the thyroid gland. Cytopathology by fine-needle aspiration.

The cytopathologic characteristics of the inflammatory and lymphoid thyroid lesions as seen in fine-needle aspirate smears of 103 patients are reviewed, with emphasis on pitfalls and association with other neoplasms. The cytologic diagnoses were as follows: subacute thyroiditis, 3; Hashimoto's thyroiditis (HT) with or without Hürthle cell nodule, 77; HT and Hürthle cell tumor, 2; HT and follicular neoplasm, 3; HT and papillary carcinoma, 5; lymphoma, 3; HT and nodular colloid goiter, 10. Fourteen patients were operated. Five erroneous diagnoses were uncovered; inexperience was the main reason for the mistakes. The greatest diagnostic difficulties are encountered in cases of Hürthle cell nodules and malignant lymphoma, but mistakes are likely to disappear after reasonable experience. Thyroid antibodies are of no help in sorting diagnostic problems, because a positive titer is only corroborative evidence of underlying HT and does not rule out an associated tumor. Conversely, a negative titer does not discard the diagnosis of HT. The association of nodular colloid goiter and HT is depicted. Problems of sampling and staining technic are discussed.

Adenocarcinoma↗

PubMed1987

Influence of needle biopsy on management of thyroid nodules: reasons to expand its use.

We have implemented a fine needle biopsy program, evaluating 426 satisfactory biopsies in 436 patients with thyroid nodules. Benign disease was diagnosed in 345 patients (232 with benign nodular goiter, 98 with lymphocytic thyroiditis, three with granulomatous thyroiditis, and 12 with cysts). Neoplasm was diagnosed in 81 patients (61 with follicular neoplasm, 12 with papillary carcinoma, three with medullary carcinoma, three with anaplastic carcinoma, one with metastatic carcinoma, and one with lymphoma). Of the 43 patients who later proved to have cancer, 24 had follicular carcinoma, 12 papillary carcinoma, one medullary carcinoma, three anaplastic carcinoma, one metastatic carcinoma, and two lymphoma. (Eight patients refused surgery or were operated upon elsewhere and lost to follow-up.) Cancer was found in 54% of patients sent to surgery. Follicular carcinoma cannot presently be separated from follicular adenoma by needle biopsy, and surgery will continue to be required in these patients (14%); however, thyroid biopsy greatly decreased the need for surgery in other patients. Erroneous diagnoses, mainly due to inexperience, decreased after the first year. A multidisciplinary approach involving the thyroidologist and cytopathologist is important, as is the close clinical follow-up of patients with nodules thought to be benign. The safety of needle biopsy, its low cost, and the accuracy of the procedure when compared to other clinical tests for thyroid nodules make it well worth the effort to make this test more widely available.

Adenocarcinoma↗

PubMed1986

Cardiac myxomas. An immunohistochemical study using endothelial, histiocytic, and smooth-muscle cell markers.

Previous immunohistochemical studies of cardiac myxomas are few in number, limited in scope and, in part, discrepant. We studied the immunoreactivity of five cardiac myxomas for factor VIII-related antigen, Ulex europaeus agglutinin I, smooth-muscle myosin, alpha 1-antitrypsin, and alpha 1-antichymotrypsin. Positive staining was present in all five tumors with each cell marker used, but varied according to the area of tumor examined. The result of this study provides further evidence of the cellular heterogeneity in these tumors that probably originate by differentiation of multipotential mesenchymal cells.

Antigens↗

PubMed1985

Primary lymphoma of the liver. Ten cases and a review of the literature.

Ten adult white patients (21-75 years old; six women, four men) presented with large cell lymphoma of the liver. Each complained of abdominal pain and/or an abdominal mass, and five had B-symptomatology of weight loss, fever (one patient), and night sweats (three patients). At laparotomy (eight patients) or by computerized tomography, liver-spleen scan and lymphangiogram (two patients with percutaneous liver biopsy only), the liver was the sole site of involvement, although subsequent staging procedures revealed bone marrow involvement in three patients. Initial biopsy interpretation was incorrect in four cases which were diagnosed as poorly differentiated carcinoma. Although uncommon, the differential diagnosis of primary liver lymphoma should be entertained when patients present with solitary (three cases) or multiple (six cases) liver defects, particularly when alpha-fetoprotein and carcinoembryonic antigen levels are normal. One patient had diffuse hepatomegaly. Treatment included biopsy (eight patients) or resection (two patients) followed by combination chemotherapy. All patients are alive from 0 to over 10 years (mean, 2.4; median, 1.8 years): six in complete remission, two with less than 6-months follow-up, and two with recurrent lymphoma. Examination of this group of patients along with 19 cases identified in the literature suggests that this is a more treatable disease than primary liver carcinoma.

Adult↗

PubMed1984

Bone marrow biopsies in patients with the acquired immunodeficiency syndrome.

Bone marrow biopsy findings in 32 homosexual patients with the acquired immunodeficiency syndrome (AIDS) or prodromal AIDS are described. A high incidence (38 per cent) of nonparatrabecular lymphohistiocytic infiltrations containing irregular small lymphocytes was observed, as well as the presence of diffuse bone marrow damage with plasmacytosis (22 per cent), decreased or absent stainable iron (50 per cent), and histologically identifiable pathogenic organisms (6 per cent). Morphologically, the lymphohistiocytic infiltrations are indistinguishable from bone marrow involvement by peripheral T-cell lymphoma, which may cause confusion, especially when a concurrent lymph node biopsy is difficult to interpret. On deeper sectioning, a specimen from one patient assumed a more granulomatous appearance. Specimens from two patients with small, poorly formed noncaseating granulomas contained demonstrable organisms.

Acquired Immunodeficiency Syndrome↗

PubMed1984

Acquired immune deficiency syndrome: postmortem findings.

The autopsies of 13 male homosexuals with acquired immune deficiency syndrome (AIDS) were reviewed. All patients had laboratory evidence of cellular immune dysfunction. The most common diagnoses made were disseminated cytomegalovirus infection in 12 patients and Kaposi's sarcoma in 10. All patients infected with cytomegalovirus had pulmonary compromise. The adrenal glands and gastrointestinal tract also were involved often by cytomegalovirus. Cytomegalovirus infection of organs uncommonly affected such as heart, meninges, cerebrum, and peripheral nerves was documented in two patients. Skin most frequently was involved by Kaposi's sarcoma, followed by gastrointestinal tract and lymph nodes. Two patients had visceral and/or nodal Kaposi's sarcoma with no skin compromise. Other important diagnoses were Pneumocystis carinii pneumonia, cryptosporidiosis, fungal infections, toxoplasmosis, and brain lymphoma. The cause of death was due to one or more infections in most patients. Kaposi's sarcoma did not contribute substantially to the cause of death, except in one patient with massive multifocal and multiorgan involvement.

Acquired Immunodeficiency Syndrome↗

PubMed1984

Chemotherapy-induced histologic changes in Wilms' tumors.

The nephrectomy specimens of 21 patients with Wilms' tumor who received preoperative chemotherapy consisting of vincristine and actinomycin D, alone or in combination, were studied pathologically; 1 patient also received radiation therapy. Pathological material from 20 randomly selected patients with Wilms' tumor who did not receive preoperative chemotherapy was reviewed and used as a control. Twenty tumors were of favorable histology, and one was unfavorable; all control tumors were of favorable histology. The histological changes were diffuse. The most marked changes occurred in the undifferentiated stroma of 18 tumors: the stroma was edematous; had a fibrovascular background, granulation tissue, and histiocytes; and lacked atypical cells. The blastematous nodules were reduced in size and necrotic or undergoing necrosis in 5 cases. Differentiated elements, including glomeruloid, tubular, and rhabdomyoblastic components, were unaffected. Vascular changes, consisting of fibrinoid necrosis, thrombosis, and acute inflammation were prominent in 15 instances. Two tumors of favorable histology, including one that was a rhabdomyomatous Wilms' tumor, and the tumor of unfavorable histology were unchanged by the therapy. In contrast, the histological changes present in only 4 of the control group, while similar, were rather minimal and focal. This evaluation helps to define the susceptibility of the different elements in Wilms' tumor to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1983

Clear cell islet cell tumor.

A patient with an islet cell tumor presented initially with a supra-renal mass that histologically had an extensive clear cell component. Electron microscopic and immunocytochemical findings were essential to prove that the extrapancreatic mass with clear cells was an unusual metastatic manifestation of an islet cell tumor. Both the pancreatic and extrapancreatic tumor cells contained neurosecretory granules and produced vasoactive intestinal polypeptide and substance P. The clear cell morphology was due to the accumulation of lipid and glycogen and cytoplasmic swelling.

Adenoma, Islet Cell↗

PubMed1983

Lymphadenopathy in homosexual men. Morbid anatomy with clinical and immunologic correlations.

This is a study of the histopathologic features of lymph nodes removed from eleven young, homosexual men, all of whom presented with lymph node enlargement of more than 3 months' duration, accompanied, in the majority of cases, by fever and weight loss. Reactive follicular and sinusoidal hyperplasia were the main findings in 10 patients. The medullary sinuses were packed with monomorphic round sinusoidal cells associated with neutrophils. In one of the 10 patients, granulomas packed the subcapsular sinuses, especially. Another patient presented with lymphoid-depleted nodes with absent germinal centers and a prominent vascular skeleton; this latter feature made it difficult to distinguish this picture from the nodal form of Kaposi's sarcoma. All patients had a history of sexual promiscuity and used "recreational" drugs. Nine of 10 patients had deficient cellular immunity and inverted T-cell helper/suppressor ratios. The only patient with normal cellular immunity had nodal granulomas. Humoral immunity was normal in all patients.

Adult↗

PubMed1983

Collagenous colitis.

Collagenous colitis is a newly described entity that clinically manifests itself as watery diarrhea of long-standing duration. The main histopathologic characteristic is the presence of a collagen band immediately beneath the colonic surface epithelium. Ultrastructurally, the collagen is deposited beneath the basement membrane, which is intact. Pathogenetically, an aberrant function of the pericryptal fibroblastic sheath may be involved.

Cathartics↗

PubMed1983

Paravaginal wolffian duct (mesonephros) adenocarcinoma: a light and electron microscopic study.

This is a report of an adenocarcinoma of mesonephric origin studied by light microscopy, electron microscopy, and immunocytochemistry. Unlike previous reports, our lesion was located paravaginally and not in the leaves of the broad ligament or in the cervix. The light microscopic features are similar to those of previous cases in the literature. Although not specific, the ultrastructural features of the tumor are similar to those of mesonephric structures and different from those of müllerian structures. The diagnosis always should be considered when a tumor occurs at the site where mesonephric remnants may be found and after exclusion of a carcinoma of other pelvic organs or a metastasis from a primary neoplasm elsewhere.

Adult↗