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Biomedical subjects

S K Landas

Publications and source records attributed to S K Landas.

At least 37 records · Page 2Linked to original sources
PubMed1993

Occurrence of melanin in pheochromocytoma.

Melanin or a melanin-like pigment was observed in six of 19 pheochromocytomas. The intracellular pigment was Fontana-positive, bleach-labile dark brown to black material and distinct from coincidental hemosiderin and lipochrome. Ultrastructural components of the pigmented tumors include melanosomes and premelanosomes. Two patients with pigmented tumors had associated von Hippel-Lindau syndrome, and one had neurofibromatosis. The occurrence of melanin and melanosomes in pheochromocytoma has not been previously reported in the English literature. It is probably a reflection of the neural crest origin of this neoplasm.

Adrenal Gland Neoplasms↗
PubMed1992

Airway injury in swine confinement workers.

OBJECTIVE: To determine whether work-related respiratory symptoms are indicative of underlying lung disease among swine confinement workers and, if so, to identify whether respiratory changes were more indicative of airway or of interstitial lung injury. DESIGN: Nested case-control study within a population-based longitudinal study. SETTING: University hospital. PARTICIPANTS: Study participants were randomly selected from a group of 207 swine confinement workers followed longitudinally. Of these, 43 workers with respiratory symptoms were identified, and 31 were randomly selected for inclusion in this study. Three control groups (swine confinement workers, neighbor farmers, and blue collar workers) without work-related respiratory symptoms were frequency-matched by age, sex, and smoking status to the symptomatic swine confinement workers. MEASUREMENTS: Spirometry and lung volumes, diffusing capacity of carbon monoxide, chest radiograph, methacholine airway challenge, and bronchoalveolar lavage were done. An endobronchial biopsy was done in the last 27 participants evaluated. RESULTS: Although spirometric measures of airflow were similar between the symptomatic swine confinement workers and the three control groups, swine confinement cases were found to have significant elevations in residual volume (126.5 +/- 28.2 L) when compared to swine confinement controls (115.4 +/- 38.4 L; P less than or equal to 0.05), neighborhood farmer controls (101.1 +/- 29.4 L; P less than or equal to 0.005), and blue collar controls (106.4 +/- 30.4 L; P less than or equal to 0.05). Swine confinement cases also had an enhanced airway response to inhaled methacholine and had thickening of the epithelial basement membrane of the lobar bronchi. No parenchymal injury was observed in the swine confinement cases. CONCLUSIONS: Our findings suggest that swine confinement workers who have work-related respiratory symptoms are at risk for airway, but not parenchymal, lung injury, and that spirometry may not accurately reflect the extent of airway injury.

Adult↗
PubMed1992

Extraskeletal myxoid chondrosarcoma of the pleura. Report of a case clinically simulating mesothelioma.

A primary extraskeletal myxoid chondrosarcoma of the pleura that clinically mimicked a malignant mesothelioma in a 66-year-old man with a history of asbestos exposure is described. Although exceedingly rare in this location, the characteristic histologic features, immunohistochemical reactivities, and ultrastructural features support the diagnosis of extraskeletal myxoid chondrosarcoma. Many ferruginous (asbestos) bodies consistent with the exposure history were found in the lung tissue sections and confirmed by energy-dispersive spectrometry. This case demonstrates an unusual pleural primary neoplasm associated with asbestos.

Aged↗
PubMed1992

Histological and angiographic effects of a pulsed holmium:YAG laser in normal and atherosclerotic human coronary arteries and aorta.

OBJECTIVE: The aims were (1) To determine the histological and angiographic effects of holmium:YAG laser energy delivered through clinical multifibre laser catheters on fresh cadaveric coronary arteries; and (2) to relate the placement of optical fibres in the catheter to patterns of tissue ablation in cadaveric aorta. METHODS: Eight fresh cadaveric hearts and segments of aorta were used. Hearts were mounted on a new pressure perfusion device. The laser catheter was delivered over a guidewire in the lumen until it met an area of resistance. The coronary artery lumen was perfused at approximately 100 mm Hg mean pressure. These arterial areas were identified on angiography, marked, and then exposed to laser energy in the range 600-3000 mJ.mm-2. Normal and atherosclerotic areas of fresh cadaveric aortic strips were exposed to increasing laser energies using either constant or increasing fluence. Coronary arteries were pressure perfused with formalin for 18-24 h at 100 mm Hg mean pressure, and aortic strips were immersed in 5% formalin. Light and scanning electron microscopy studies were carried out. RESULTS: There were no perforations or dissections by angiography in the fresh coronary arteries. One of 15 normal coronary artery segments and 10 of 16 of the pressure perfused, fixed, atherosclerotic coronary artery segments showed thermal changes associated with atherosclerotic plaque ablation. In aortic tissue, thermal effects extended 0 to 0.6 mm lateral to the ablated crater. Acoustic effects were seen only in the aortic strips after ablation at fluences > 1000 mJ.mm-2. The "dead spaces" around the optical fibres in the catheter resulted in significant amounts of coagulated tissue fragments remaining in the crater. CONCLUSIONS: Holmium:YAG laser energy delivered through multifibre catheters ablated atherosclerotic tissue in coronary arteries with minimal damage to the normal walls. The cadaveric coronary artery perfusion apparatus is useful for assessing catheter delivery and mobility and the effects of laser energy on the coaxially orientated normal and atherosclerotic coronary arterial wall.

Aorta↗
PubMed1992

Lipogranulomas and gold in the liver in rheumatoid arthritis.

Liver biopsies have been performed routinely as part of a protocol to evaluate methotrexate therapy in severe rheumatoid arthritis. All patients in the study had failed standard medical therapy, including gold treatment. Twenty-three of 41 patients (56%) had well-formed lipogranulomas (LGs) in the lobules, compared with an incidence of approximately 5% in our general biopsy population. Twenty-seven of 41 patients (66%) had a unique pigment in their livers. In 20 of these, the pigment was in LGs; in the seven patients with pigment not associated with lobular LG, it was found in lipid droplets in portal triads. The pigment varied from irregular pale brown granules slightly larger than those of hemosiderin, to smaller black round granules. Lipogranuloma-associated pigment of this type is an unusual finding, reminiscent of argyria. There was a variable appearance upon polarization, the black granules at times being strikingly refractile. There was a positive correlation between the prominence of LG and the quantity of pigment. The pigment resembled that described with gold deposition in other tissues. Radiographic microanalysis of both brown and black granules was performed in three cases. Characteristic spectra (energy-dispersive spectroscopy) demonstrated the presence of gold in each case. Silver was not identified. The high incidence of LG may reflect the frequent administration of gold in an oily vehicle. Gold may remain trapped in the liver for a prolonged time. Thus far, we have not detected any adverse effect from the presence of LG-associated gold.

Arthritis, Rheumatoid↗
PubMed1992

Ultrafast computed tomography in experimental pulmonary embolism.

Computed tomography (CT) has proven useful in the diagnosis of central pulmonary embolism; however, its ability to detect peripheral emboli has not been established. The authors evaluate the usefulness of ultrafast CT (UFCT) in detecting experimental peripheral pulmonary emboli. Three Gelfoam emboli measuring 0.7 x 1.5 cm were introduced into the pulmonary arteries of each of seven dogs, and contiguous, 3-mm, axial UFCT images from the lung apex to the base were obtained after the administration of a contrast bolus. After scanning, the dogs were killed, and the locations of the emboli were determined by a pulmonary pathologist blinded to the imaging results. Concomitantly, the locations of the emboli on the UFCT images were determined by consensus of three chest radiologists blinded to the autopsy results. All 21 emboli were identified on UFCT images; the locations of the emboli corresponded exactly with the autopsy findings. The authors conclude that UFCT can reliably detect Gelfoam emboli in second- to fourth-division pulmonary vessels. Further studies are needed to determine if in vivo blood clots can be similarly visualized.

Animals↗
PubMed1992

Diagnosis of pulmonary arteriovenous malformation by ultrafast chest computed tomography in Rendu-Osler-Weber syndrome with cerebral ischemia--a case report.

Pulmonary arteriovenous malformations occur in 15-20% of patients with Rendu-Osler-Weber syndrome and can be the source of paradoxical emboli causing cerebral ischemia, septic emboli leading to brain abscesses, or polycythemia causing hyperviscosity and cerebral ischemia. The diagnosis of these malformations may be elusive, since classic clinical or radiologic findings may be absent in some patients. The authors report a patient with Rendu-Osler-Weber syndrome with cerebral ischemia who had normal findings from a pulmonary examination and chest roentgenogram. An ultrafast computed tomography scan of the chest demonstrated, however, a pulmonary arteriovenous malformation in the right upper lobe that was successfully resected. Ultrafast computed tomography of the chest is a relatively noninvasive method of screening for a pulmonary arteriovenous malformation in a patient with Rendu-Osler-Weber syndrome and otherwise unexplained neurologic symptoms.

Arteriovenous Malformations↗
PubMed1992

Post-mortem observations of a recent radiofrequency catheter ablation site.

The acute and chronic gross and microscopic morphologic changes present in myocardium after radiofrequency catheter ablation have been previously described in animal experiments. Acute changes have also been described in four cadaveric human specimens. We describe post-mortem observations of a recent radiofrequency catheter ablation site in a patient who underwent successful ablation for refractory ventricular tachycardia. Our gross and microscopic observations are similar to those previously described in animal experiments and confirm that the animal experimental results can be extrapolated to human hearts. As the use of radiofrequency becomes more prevalent as an alternative treatment for refractory cardiac tachycardias, pathologists will be called upon to identify post-mortem the lesions described. These lesions can be specifically identified, which can serve as a useful verification for this procedure.

Aged↗
PubMed1991

Black thyroid: a pitfall for aspiration cytology.

Black thyroid discoloration following long-standing use of minocycline has been reported. Morphologic findings of aspiration cytology of these lesions was first reported from The Ohio State University. This abstract describes a second case of black thyroid that was preceded by aspiration cytology. In both cases, thyroidectomies were performed based on "indeterminate" fine-needle aspiration cytology (FNAC). Degenerative changes in follicular epithelial cells in black thyroid causes nuclear hyperchromasia and chromatin clumping, which may be mistaken for neoplasia. Pigment present in follicular epithelial cells and macrophages may be obscured by pigments with similar microscopic appearances, such as hemosiderin. A clinical history of the chronic use of a tetracycline derivative should alert the pathologist to the possibility of black thyroid. Diagnosis may be made by applying special stains on the cell block. The pigment stains with Melanin stain (Fontana) and bleaches with potassium permanganate. In the light of increasing use of FNAC of the thyroid gland and the large number of patients who received tetracycline therapy in the last two decades, it is likely that some practicing cytopathologists may experience this pitfall.

Adult↗
PubMed1991

Pleomorphic melanoma mimicking sarcoma.

Malignant melanoma may display a wide variety of unusual morphologic patterns that simulate unrelated neoplasms. The diagnostic approach to such complex and morphologically divergent lesions requires thorough and extensive scrutiny not only by routine light microscopy, but also by immunohistochemical and ultrastructural evaluation. We have reported the case of a patient with a mass on the heel exhibiting complex morphology that illustrates the value of such a systematic approach.

Diagnosis, Differential↗
PubMed1991

Evidence that epidermal alloantigen Epa-1 is an immunogen for murine heart as well as skin allograft rejection.

Epa-1 is a non-H-2 mouse alloantigen defined by MHC-restricted, CD8+ cytotoxic T cells. In vitro it is a strong determinant for the lysis of epidermal cells, fibroblasts, and macrophages but not lymphocytes, and in vivo it functions as a target for skin allograft rejection and cutaneous graft-versus-host reactions. Genetically, Epa-1 appears to be the nonpolymorphic manifestation of a loss mutation. The establishment of C3H.Epa-1 (Epa), an Epa-1+ congenic strain on the Epa-1- C3H/HeJ (C3H) inbred strain background, facilitated the investigation of the role of Epa-1 in skin and heart allograft rejection. C3H females and males rejected first-set Epa skin grafts with median survival times (MSTs) of 20 and 30 days, respectively. However, there was a strong factor of immunization, because all second-set skin allografts were rejected by hosts of both sexes within 10 days. In contrast, all Epa hosts of both sexes permanently accepted C3H skin allografts, consistent with Epa-1 arising from a loss mutation. C3H hosts of both sexes rejected primarily vascularized first-set Epa heart allografts in similar tempo to first-set Epa skin allografts, with MSTs of about 30 days. However, in contrast to the accelerated rejection of skin allografts, sensitized C3H hosts rejected Epa heart allografts in chronic fashion, with some transplants showing very prolonged survival. Thus, Epa-1 is a relatively strong determinant of skin allograft rejection but a weaker determinant of heart allograft rejection.

Animals↗
PubMed1991

Mica-associated pulmonary interstitial fibrosis.

We present the clinical and biopsy findings of a 63-yr-old white male with interstitial pulmonary fibrosis and a long history of extensive exposure to mica while working in the rubber industry. The patient presented 30 yr after the initial exposure with complaints of progressive shortness of breath and a chronic nonproductive cough. Pulmonary function testing revealed restrictive lung function with a mild reduction in the total lung capacity (80% of predicted) and a moderate-to-severe reduction in the diffusing capacity of carbon monoxide (50% of predicted). The chest radiogram and high-resolution chest CT scan showed diffuse fibrosis and focal honeycombing involving the upper and lower lung zones bilaterally. Bronchoalveolar lavage revealed 20% neutrophils in the lavage fluid with abundant rectangular flaking crystals. Open-lung biopsy exhibited extensive fibrosis and architectural remodeling with abundant sheets and fragments of engulfed polarizable crystalline material. Energy-dispersive spectroscopy and electron diffraction studies confirmed the material to have the features of mica. Asbestos and other silicates were not identified. The documentation of prolonged exposure to mica, the clinical and radiographic features of severe interstitial fibrosis, and the histopathologic delineation of the interstitial lesion, including spectroscopic and crystallographic verification of crystalline mica, support the causal relationship between mica and interstitial fibrosis.

Aged↗
PubMed1991

Glial fibrillary acidic protein expression in pleomorphic adenoma, chordoma, and astrocytoma. A comparison of three antibodies.

Glial fibrillary acidic protein (GFAP) is a major constituent of glial cytoplasmic intermediate filaments. Glial fibrillary acidic protein expression has been accepted as a marker of astroglial differentiation or origin. However, GFAP expression has been demonstrated in a variety of normal and neoplastic tissues outside the central nervous system, including pleomorphic adenomas, chordomas, bone, and cartilage. It has been postulated that coexpression of GFAP and vimentin in neoplastic myoepithelial cells in pleomorphic adenomas reflects early chondroid differentiation. Glial fibrillary acidic protein expression in chondromyxoid and chordoid tumors was studied in formaldehyde solution-fixed, paraffin-embedded sections of 20 pleomorphic adenomas and 10 chordomas by the immunoperoxidase method with the use of commercially available monoclonal (n = 2) and polyclonal (n = 1) antibodies. All pleomorphic adenomas and chordomas demonstrated expression of GFAP with the use of the polyclonal antibody (Biomeda Corp [Foster City, Calif]). Variable expression of GFAP was present in 90% (18/20) and 70% (14/20) of pleomorphic adenomas, and in 20% (2/10) and 0% of chordomas, with the use of the two monoclonal preparations (Dakopatts [Glostrup, Denmark] and BioGenex Laboratories [San Ramon, Calif]), respectively. Normal brain tissue and eight astrocytomas were used as "controls" to compare staining intensity and quality between the polyclonal and monoclonal anti-GFAP antibodies. Glial fibrillary acidic protein positivity with the polyclonal antibody was more intense than that with either monoclonal antibody despite similar (congruent) distributions of tumor cell types that were stained in control brain and astrocytoma tissues. The GFAP polyclonal antibody was more frequently immunoreactive than the monoclonal antibodies, particularly in cells that exhibited chondroid differentiation. These findings may have practical application in surgical pathology.

Antibodies, Monoclonal↗
PubMed1991

Immunohistochemical distinction of classic and chondroid chordomas.

Chondroid chordomas are cartilage-rich neoplasms, most often located in the spheno-occipital region, that have a better prognosis than classic chordomas. The immunohistochemical features of 19 classic and chondroid chordomas were studied retrospectively using avidin-biotin-complex (ABC) immunoperoxidase histochemistry on formalin-fixed, paraffin-embedded tissue. Of the 19 tumors, all located in the spheno-occipital region, 5 exhibited predominantly chondroid morphologic features. The 14 classic chordomas showed the following pattern of antigen expression (percent of tumors positive): epithelial membrane antigen (EMA) 100%, AE 1/3 (a "cocktail" of monoclonal antibodies directed against low and high molecular weight epidermal cytokeratins) 100%, DP keratin (DPK) 100%, vimentin 100%, S100 86%, neuron specific enolase (NSE) 100%, carcinoembryonic antigen (CEA) 57%, and HMB-45 (an anti-melanoma-associated antibody) 57%. The five chondroid chordomas exhibited the following pattern: EMA 0%, AE 1/3 0%, DPK 0%, vimentin 100%, S100 100%, NSE 100%, CEA 0%, and HMB-45 0%. The focal, weak HMB-45 positivity (performed on the index case because of a clinical concern of metastatic melanoma) seen in 57% of the classic chordomas is a previously unreported finding. This finding suggests either that classic chordomas are capable of HMB-45 expression or that this antibody has broader reactivity than previously recognized. The lack of cytokeratin, EMA, and CEA expression by the chondroid chordomas is similar to chondrosarcomas as reported in the literature and dissimilar to the classic chordoma group. These immunohistochemical findings suggest that chondroid chordomas may more validly be classified as low grade chondrosarcomas.

Adolescent↗
PubMed1990

Nonpigmented papillary carcinoma in a black thyroid gland.

A case of papillary thyroid carcinoma occurring in a 27-year-old man with black thyroid syndrome is reported. The tumor, in contrast to the remaining thyroid, was not pigmented. The significance and potential utility of the differential pigmentation are discussed.

Adult↗